A diverse array of assistive technologies have been developed to help Visually Impaired People (VIP) face many basic daily autonomy challenges. Inertial measurement unit sensors, on the other hand, have been used for navigation, guidance, and localization but especially for full body motion tracking due to their low cost and miniaturization, which have allowed the estimation of kinematic parameters and biomechanical analysis for different field of applications. The aim of this work was to present a comprehensive approach of assistive technologies for VIP that include inertial sensors as input, producing results on the comprehension of technical characteristics of the inertial sensors, the methodologies applied, and their specific role in each developed system. The results show that there are just a few inertial sensor-based systems. However, these sensors provide essential information when combined with optical sensors and radio signals for navigation and special application fields. The discussion includes new avenues of research, missing elements, and usability analysis, since a limitation evidenced in the selected articles is the lack of user-centered designs. Finally, regarding application fields, it has been highlighted that a gap exists in the literature regarding aids for rehabilitation and biomechanical analysis of VIP. Most of the findings are focused on navigation and obstacle detection, and this should be considered for future applications. According to the World Health Organization, about 28% of the global population (2.2 billion) is visually impaired or blind . Vision In addition, there are great advances in miniaturized sensors capable of providing parameters of moving objects, such as position and velocity ,16,17. TAn important factor constraining the development of these assistive technologies is that there are limitations regarding the accuracy of these systems. Another important factor is poor acceptance by the blind community, which is a factor related to the limitation of the visual rehabilitation programs in which these systems should be included .Technologies based on inertial measurement unit sensors (IMU) are used in a large and ever-growing number of applications such as intelligence guidance, mineral exploration, self-driving robots , full-boThere is a large amount of literature on the use of inertial sensors to estimate position and orientation. However, as mentioned before, sensor acquisition in ETAS and other VIP systems developed for navigation and assistance are not primarily IMU-based technologies, although their sensing includes IMUs data. This is due to integration drift, which is a known disadvantage of IMUs that can generate position errors in the dead-reckoning method. To face the drift error, many authors suggest incorporating inertial measurement as part of the acquired sensing and fusing the values with the sensing of optic sensors and global positioning systems (GPS) also to include the drift reduction algorithms, which greatly contribute to a more accurate positioning within IMU data ,57,58. ALiterature searches were performed in the IEEE Xplore (IE), Web of Science (WoS), and PubMed databases. Considering rapid advances in technology, we focused on articles published in the last 5 years (until December 2020) to give an overview of the most recent developments. Searches were performed in IE, WoS, and PubMed on 15 December 2020. Only articles written in English were considered. Our screening was filtered in two stages: a general search and a refinement in the three databases. Terms used in the general search were . For the refinement, the terms were .The following criteria were used to select the articles included in this review: (1) articles with proposed systems including IMU sensor technology with at least one kind of measurement , (2) in the implementation of IoT systems on the developments and (3) rehabilitation or physical monitoring of daily life activities and (4) in publications within experimental results of their developments, including the participation of VIP or blindfolded (BF) volunteers.The initial search resulted in 637 articles . To be included in this review, the aim of an article was required to be a development to aid VIP exclusively; articles regarding navigation, human motion, or PA monitoring not developed for VIP were excluded. After applying the selection criteria and removing duplicates, 40 articles remained to be reviewed .The articles were summarized and divided into four categories according to the inertial sensor used, “sensor input”. The first section discusses nine articles reporting to use accelerometer input, the second section considers four articles that used gyroscope input, the third and four sections discuss 13 articles using both accelerometer and gyroscope input and 14 articles reported that used accelerometer, gyroscope, and magnetometer input.Then, the usability, the application trends, and the artificial intelligence incorporation in the reviewed articles are discussed. Note that in the extension of this section, the role of the inertial measurement unit in each development is highlighted; however, most of the selected articles integrate sensor fusion in which other types of sensors  are used.As shown in The Actigraph Corp wearable accelerometers were used in many clinical trials found in the systematic review. The accelerometers were used to measure PA within the VI community, with a major experimental focus on kids and older adults ,61,62. SX, Y, and Z-axis in order to remove negative values, and a G target value is representative for individual neural network training.Nkechinyere et al.  develope2) was previously settled upon by trial.Vibration or shocks could also be determined by thresholds fixed for each axis. Case in point, within the system of Hirano et al., the vibration of a KXR94-2050 3-axis accelerometer sensor was used to allow blind runners to synchronize and match their running tempo with sighted guides see . The algThe work of  presentsA gyroscope measures angular velocity: the rate of change of the sensor’s orientation. Thus, the integration of gyroscope measurements provides information about the orientation of the sensor. Four articles reported using gyroscope input for different roles within sensor fusion, as shown in Z-axis signal. The sweeping frequency corresponded to the number of complete sweep cycles performed per second. The sweeping speed was defined as the angular velocity during the sweeping period. In addition, the authors experimented with grasping characteristics based on the positions of the thumb and index finger. They added an optoelectronic motion tracking system  to obtain accurate cane orientation angles related to tilt, grip rotation, and sweeping movement.In what can be considered a “rehabilitation” application, the authors of  used theOn a different device proposed to help blind people detect stairs , the gyrWith the gyroscope values, the buzzers also could provide information about the distance from the step as well as the height and depth of the step; in this system, a MPU-6050 IMU was used to obtain the tilt angle. The same sensor was used in , where tOommen et al.  developeAccelerometers and gyroscopes are frequently used together in navigation situations when the position and orientation  of a device or person are of interest. Articles that reported using input from both accelerometers and gyroscopes sensors represented 33% of those reviewed. As expected, all dealt with navigation aid applications. The most frequently cited IMU was the MPU-6050 from TDK InvenSense, which has a Digital Motion Processor (DMP) to the fusion of the three-axis accelerometer and three-axis gyroscope; more details are described in Z-axis of acceleration  is analyzed to identify steps, while the minimum and maximum vertical acceleration signals are retrieved for peak detection and zero crossings. These features helped to evaluate cardinality so the algorithm could be reliable with different users and different walking speeds. Displacement (s) was evaluated using the algorithm proposed by Weinberg for MEMs in 2002 97], thisPose estimation is referred to the estimation of both orientation and position by modeling the accelerometer and gyroscope measurements to the dynamics . In dynaA Kalman filter-based algorithm was implemented by  using thThis KF-based algorithms may not apply to all positioning estimation scenarios; some other non-linear models that are derivatives of the EKF are also suggested by authors to face the estimation accuracy problems of the sensor states . HoweverThe positioning models can be improved with hardware implementation when fused with local markers as in the graph-based PDR model presented by  or the pAs mentioned in the introduction, an important factor constraining the development of systems to aid the VI is the acceptance of these technologies by the visually impaired community. The following section summarizes information from the research articles presented in this systematic review that pertains to the participation of VIP in tests of proposed systems.Apart from the six articles focused on the measurement of PA, which are based on the participation of VI; only eleven of the 34 remaining articles summarized in the review tested proposed systems with VI volunteers or include VI during their experimental phase ,93,95,98Concerning usability questionnaires after prototypes testing, only three of the 40 articles reported questionnaires of experience or qualitative feedback after VI participation in the tests, and two reported grading performance or obtaining qualitative feedback from BF participants. The relatively few questionnaires mentioned solicited feedback information such as ease of use or wearability usefulness; response time; independence and localization; sense of safety; and advice for future modifications . Nor didThe paucity of user feedback reported is alarming. VIP and volunteer feedback are important to the development of such systems; targeted users must be considered during the development process or usability may be compromised.“Navigation and Object recognition” was the most prevalent VIP application and was cited in 38% of systematic review articles (15 articles), as shown in “Navigation only” was the second most cited field of application and was represented in 23% of the reviewed articles. Researchers tended to use IMUs for several tracking purposes in the systems described: primarily PDR, pose estimation, and step detection. Smartphone IMUs were used as input to algorithms in more than half of the articles to provide “simple architecture” solutions. Only one article reported the use of a single IMU measurement (gyroscope) for input, while 78% developed devices or systems that used three measurement inputs: accelerometer, gyroscope, and magnetometer. The authors of one article did not declare the type of sensor input but referred only to “IMU” input. However, given the nature of the extracted data (absolute orientation), it can be assumed input was from at least two sensors. Although the IMUs listed  are reported to be more accurate when compared to smartphone IMUs, one article reported the use of smartphone inertial sensing for “Navigation and Object Detection” as compared to five articles in the “Navigation only” application field.About 33% of the articles were categorized as dealing with “Sports/daily activity” application. We included articles that described or reported research focused on measures of physical activity of VIP, monitoring or improving QoL activities, and systems developed to aid athletes with visual impairments. Research that focuses on monitoring physiological and behavioral patterns with wearable devices, such as inertial sensors, has become more prevalent due to the increasing availability of wearable small devices . WearablThe IMUs in this application field section were used basically to measure PA by wrist-worn accelerometers to monitor daily life activity by using accelerometer sensor input only. For sports, the roles of the inertial sensors depend on the four identified sports: running (sense the foot movements), biking (detect the right edge of the road), swimming (track the direction of gravity), and roller skating (body orientation and head tracking). Fifteen percent of the articles in this section reported the use of smartphone IMU sensing; 46% reported the use of ActiGraph accelerometers. The Bosch BNO055 and BMI055, the KXR94-2050, and the TDK Inversense MPU-9250 were used in different systems in this application field. For input, 61% of the review articles in this application field used accelerometer data exclusively; one reported using a gyroscope, while four used sensor fusions of acceleration and gyroscope.Rehabilitation is the systematic process in which VIP are provided with tools to help them deal with their visual impairments with greater independence and self-confidence. These tools include activities such as learning Braille, learning how to use a cane, sightless feeding of themselves, and optimizing the use of residual vision and teaching skills in order to improve visual functioning in daily life , as wellThe integration of IA architectures was found in twelve of the reviewed assistive technologies; nevertheless, only 17% of these articles (2) used the IMU sensor as input (data feeder). Instead, the rest of the authors used optical sensors from camaras as an algorithm’s input. This is because most of the developments were focused on object detection, object recognition, and obstacle avoidance. In this case, several machine learning architectures were tested, such as decision tress  and clasThe biomechanical research of visually impaired people is an important research field for injury prevention and for evidence-based rehabilitation methodology. Most of the medical research found in the review was focused on evaluating the physical activity of people with visual impairment; however, visual impairment is usually accompanied by age-related degenerative diseases. That is why a part of the literature focused on visual impairment and blindness is dedicated to study the biomechanical analysis, such as parameters of gait and posture ,135,136.Analysis of gait parameters using inertial sensors, on the other hand, has been an important topic found in the literature for more than a decade . This liIn addition, biomechanics and quantification of the long cane for analysis of the motion parameters and performance using inertial sensors is also a research field that can be considered as a new avenue of research and a missing element. Since as shown in the few studies that are found in the literature regarding this topic, a sophisticated 3D motion analysis equipment has been required in both studies to conduct the motion acquisitions for further analysis ,142. HowA limitation to the present review may be the fact that only three databases were included in the systematic article search. We selected three databases that we consider are relevant to the research topic; perhaps more articles addressing the use of inertial sensors in assistive technologies for visually impaired people are found in the literature but did not comply with the eligibility criteria and thus are not included because they are indexed in other databases.Another limitation lies in the fact that there is no qualitative assessment of the selected articles; instead, all the articles found in the review that met the criteria were included for in-depth analysis, including conferences and short papers. As a result, this review provides a comprehensive systematic review of the recent literature, focusing on the discussion of the use of the inertial sensors.A systematic review of research articles was conducted to find system developments that used inertial measurement unit sensors to aid the visually impaired people in assistive technologies. Reviewed articles were categorized according to the type of IMU input used and the role of these IMUs, including pose estimation , identification of human motion, i.e., PA and falling, but also specific roles for each application field such as measurement of the sweeping velocity of a white cane, detection of the right edge of the road for blind bikers, or tracking the direction of gravity when swimming. The major approach of the findings was sensor fusion of accelerometers, gyroscopes, and magnetometers (35%), while the less common approach of the findings was the use of gyroscope input (10%). In addition to the IMU data, sensor fusion in most of the articles included GPS (20%) and optical sensors such as RGB-D (16%) and RGB (15%) cameras as ultrasonic sensors (16%). Second, better precision in navigation and positioning estimation can be achieved when there is a fusion of UWB, line lasers, and velocity sensors in hardware when implementing local markers and deep learning architecture in software development. The smaller errors in navigation reported were due to IMU sensor fusion with an RGB camera sensor and the use of external inertial sensors, for instance, MPU-6050 and VN-100 IMU/AHRS instead of a smartphone inertial sensor, which is less precise. In many of the articles summarized, “simple” architecture of the systems to aid the athletes is observed, suggesting that the use of inertial sensors is quite applicable in this area, only more knowledge of the specific activity is needed to create an assistive system. In addition, by using accelerometers only, ActiGraph IMUs were the most commonly used, due to the function of measure of PA. The results indicate that there are new avenues of research within the integration of AI with the use of inertial sensors as feeders to improve the accuracy of the assistive devices developed as navigation assistance. There are also missing elements in the literature such as technological developments to aid the rehabilitation process, the use of inertial sensors for biomechanical analysis in gait and posture parameters, and also biomechanics of usage of the long cane within VIP. In addition, the results have shown that it is necessary to promote as well the inclusion of technology in these biomedical research areas. Finally, a significant limitation evidenced by this review is the fact that the designed aids for the visually impaired lack user-centered designs. Most of the authors used blindfolded persons instead of actual blind persons during the validation of the developments, and only 8% of the reviewed developments included a usability questionnaire for the VI, which should be considered for future research.


NSR recently talked to Professor Yi-Gang Xu, GIG’s Director, about why the study of the Earth's interior is essential, the current progress of deep Earth science in China, and what makes our planet habitable.The deep Earth is the engine of whole Earth systems and plays a key role in surface evolution and geological hazards. Scientists have been deciphering the internal processes that shape our habitable planet, especially since the formulation of plate tectonics theory. To date, how the deep Earth works remains mysterious. At the end of 2020, the Chinese Academy of Sciences (CAS) started to set up the Center for Excellence in Deep Earth Science, headquartered in the Guangzhou Institute of Geochemistry (GIG), with long-term support for these emerging and interdisciplinary research areas.  NSR: Why does the deep Earth matter?Xu: Earth is the only habitable planet in the Solar System due to two unique characteristics. First, Earth has an active interior, featuring vigorous convection of the mantle and liquid outer core. It is perhaps the core convection that generates and maintains the geomagnetic field, which is so important to the origin and evolution of life. The geomagnetic field forms an invincible barrier blocking solar winds and high-energy particle attacks. At the same time, it prevents the atmosphere from escaping. Nowadays, Earth is middle-aged in terms of its energy budget, whereas the Moon ‘died’ about 3.0 billion years ago. Mars is in its final ‘dying’ stage, and its residual energy is insufficient to maintain its full operation.Second, although nearly all planetary bodies undergo tectonics giving birth to volcanoes, mountains, craters and faults on their surfaces, Earth appears to be the only planet with tectonic plates in the Solar System. Over the past 50 years, geoscientists have made great achievements in understanding our planet's composition, structure and dynamics. The discovery of continental drift and the consequent establishment of plate tectonics theory is definitely one of the most significant scientific breakthroughs of the 20th century. Like quantum mechanics in physics and genetic codes in biology, plate tectonics has revolutionized Earth science. In principle, plate tectonics is elegantly simple and has fundamentally transformed our concept of how the world works. It explains the movements of the Earth’s surface, typically ∼100 km thick, providing a uniform framework for decoding the processes of spreading at ocean ridges, mountain building, earthquakes, volcanoes and mineralization at convergent boundaries. It is highly relevant to human society with regard to atmospheric evolution and climate change over billions of years. More importantly, new discoveries indicate that plate tectonics has played an essential role in setting up life on Earth.Although plate tectonics is limited to our planet's uppermost layer , the ultimate driving force lies in its deep interior, such as mantle convection. In this sense, understanding plate tectonics and Earth's deep interior is indispensable in understanding what makes our planet habitable.NSR: Can you provide an example of how deep processes affect Earth's habitability?Xu: I would like to take large-scale volcanism as an example because volcanoes originate from the deep Earth, and their eruptive materials such as ashes, gases and debris can penetrate diverse surface spheres such as the hydrosphere, biosphere, cryosphere and atmosphere. Consequently, volcanism can be regarded as a vital link between the geodynamic processes in Earth's deep interior and surface system evolution. There are three principal types of volcanism on Earth: mid-oceanic ridge volcanism, subduction-related arc volcanism and intraplate volcanism, in the descending order of eruption volume. The last type of volcanism is emphasized here, despite its subordinate volumes throughout Earth's entire history. If not all, many of these intraplate volcanoes are related to hot spots. They are created by high-temperature mantle plumes that exist below the tectonic plates, probably rooted in the core-mantle boundary region. The Permian Emeishan Flood Basalt in southwest China is such a typical example. It appeared ∼260 million years ago and covered an area of over half a million square kilometers. About 8 million years later, another giant continental flood basalt province, the Siberian Traps, erupted over a very short period between tens of thousands of years and hundreds of thousands. This province covered an area of >2 million square kilometers and produced 4 million cubic kilometers, corresponding to an extremely high rate of eruption. Such devastating volcanic eruptions released countless greenhouse and harmful gases into the atmosphere, significantly increasing Earth's surface temperature  and affecting other parameters that are critical to habitability. A series of processes resulted in the most severe biotic crisis in the Phanerozoic. Over 90% of the oceans’ species, about 70% of vertebrate families on the land, and most land vegetation died off by the end of the Permian ∼250 million years ago.Like quantum mechanics in physics and genetic codes in biology, plate tectonics has revolutionized Earth science.—Yi-Gang XuNSR: This is the largest mass extinction in Earth's history as we know it. Life almost came to an end at that time. In today's world, what is the significance of deep Earth knowledge from a social perspective?Xu: From a social perspective, the human species depends on mineral and energy resources. Industrial civilization has boomed since geoscientists have been able to discover and exploit these natural resources on a large scale. Mineral resources hatch the tools that allow society to provide manufactured goods and fuel to billions of people. The increasing population continually puts more pressure on resource supply. Understanding how the deep Earth works is critical for natural resource exploration and management. In particular, understanding fluid movement within the deep solid Earth can reveal the formation mechanisms and geological characteristics of available resources. Nowadays, geoscientists view the Earth as a whole system and integrate geology, oceanography, hydrology, atmosphere and many other disciplines into the Earth system. The deep Earth lies in our blue planet's center, and has had evolving interactions with the rest of the Earth system over the past 4.5 billion years. Earth's internal processes ultimately modulate most resources, where plate tectonics and plume tectonics provide a basis for understanding the origins and location-scale distributions of mineral and energy deposits. For example, several hundred million tons of copper have been exhumed from plate boundaries around the circum-Pacific region. The world's largest platinum group element (PGE) deposits and Ti-V deposits are respectively associated with the Bushveld Complex in South Africa and Emeishan large igneous province, both of which are mantle plume-related.NSR: What are the goals of deep Earth research and exploration in China?Xu: The goals of deep Earth research and exploration in China are two-fold. On the one hand, it is highly relevant to meet national demands. China's rapid economic development requires a sustainable supply of diverse resources. However, while resource exploration depths in major ore countries now frequently exceed 2000 m, most ore exploration depths in China are <500 m. Maintaining sustainable economic development in China requires the prospection of more resources from the deeper crustal level. High-resolution visualization of the deep lithospheric structure and effective prospecting technology are crucial to meet this national demand.On the other hand, deep Earth research offers potential breakthroughs in Earth science. As I mentioned previously, while the plate tectonics theory is one of the great scientific breakthroughs of the 20th century, it nevertheless only deals with the dynamics of the superficial layer, which is <100 km thick. Although it is known that the driving force of plate tectonics is in the Earth's deep interior, how it operates remains mostly unknown. More knowledge about the structure, composition and dynamics of the deep interior will certainly help refine Earth science theory or even establish a new theory.NSR: Our understanding is only skin-deep. Steady thermal convection in the Earth's mantle cannot explain the rifting of supercontinents. We need additional mechanisms. So, what are we embracing in the post-plate tectonics era?Xu: Following demands for a new science of the Earth, Earth System Science emerged as an ambitious inter- and transdisciplinary collaborative effort in the 1980s. A major success is global change studies, involving the integration of many different disciplines of atmospheric physics and chemistry, physical oceanography, climatology and paleo-environmental reconstruction. We are looking forward to a significant understanding of the interaction between multiple spheres. Nevertheless, the deep integration of the Earth System Science framework is one of the great challenges of our time. The whole of Earth's interior must be included in the Earth system, especially when geological processes through time are taken into account. WhileMore knowledge about the structure, composition and dynamics of the deep interior will certainly help refine Earth science theory or even establish a new theory.—Yi-Gang Xuthe deep Earth is presumably the engine of the Earth system as a whole, it is not yet clear to us how it works and how Earth's deep processes govern the surface system evolution. Considering the prevailing challenges in Earth System Science, we launched a multi-disciplinary strategic priority research program in 2016 with support from the CAS. Aiming to understand how Earth's surface systems interact with its interior processes, the program focuses on the three major aspects of Earth's deep interior: the state of the deep Earth, its internal processes, as well as their connection with Earth's surface systems.NSR: For the past five years (2016–2020), the study of Earth's interior has been one of the Strategic Priority Research Programs (Category B) of CAS—‘linking the Earth's interior processes and surface system evolution’—and it is led by GIG. Could you tell us a bit more about this program?Xu: We are grateful to the CAS headquarters for funding this Strategic Priority Research Program. In my opinion, this represents a major step towards promoting deep Earth exploration in China. The program consists of three sub-projects. Project one aims to probe the constituents and structural heterogeneity of the Earth's deep interior through multiple approaches. These include seismology, mineral physics, computational geochemistry, isotope geochemistry, geo- and paleomagnetism, and comparative planetary science. Project two aims to better understand the interactions between Earth's interior spheres and the surface, and its recycling processes, through plate subduction and mantle plume. Special attention will be paid to the distribution and transportation of volatiles in different spheres and their influences on the physio-chemical properties of the deep mantle and deep dynamic processes. The last project is designed to assess how Earth's surface systems respond to its deep interior processes, especially in terms of the climatic and oceanic changes and their roles in the evolution of life.2 and the dominant mantle oxide O. Last but not least, multiple efforts haveThis year, we are close to concluding the program and summarizing our major achievements. Firstly, our seismic imaging capability has significantly improved, and we are now quantifying the small-scale structural heterogeneity of the deep Earth. Interestingly, the roughness of the 660-km boundary is not equally distributed at the bottom of the mantle transition zone. In other words, there are massive mountains not only lying on the Earth's surface but also hidden inside the Earth. Secondly, about 200 meteorite impact craters have been found on Earth so far. One, the Xiuyan crater, is in the Liaodong Peninsula of China. Here, Dr Ming Chen at GIG discovered natural diamond formation from reactions between COAlthough it is known that the driving force of plate tectonics is in the Earth's deep interior, how it operates remains mostly unknown.—Yi-Gang Xufocused on the causes of the Permian-Triassic boundary (PTB) extinction when nearly 90% of the planet's species were killed. We found that large-scale volcanism and rapidly enhanced continental weathering might have delivered excessive nutrients to oceans, causing marine eutrophication, anoxia, acidification and ecological perturbation, and thus, might ultimately have led to the end-Permian mass extinction.NSR: In addition to scientific progress, what are the main benefits of the operation of this program?Xu: From a managerial point of view, two points are worth mentioning. The first concerns cross-disciplinary interaction: the CAS strategic priority program brings together two different teams that had rarely worked together before, one focusing on the deep interior and the other focusing on the surface system. The collaboration and interaction between these two groups yield some very exciting results and provide new perspectives on Earth system science theory development. The second is that such a program's operation considerably enhances our ability in geophysical exploration, geochemical tracing, geochronological dating and experimental and computational modeling. Both the new philosophy of research and the instrumentation of relevant analytical platforms and simulation devices have considerably promoted deep Earth research in China and have significantly advanced our understanding of the physics, chemistry and dynamics of Earth's interior.I am delighted that this progress has been recognized by the CAS and the National Natural Science Foundation of China (NSFC). In particular, we are setting up the CAS Center for Excellence in Deep Earth Science in Guangzhou. Meanwhile, CAS and NSFC have co-funded strategic research from 2021 to 2035 on Earth's internal processes and habitability. With the help of these new programs, we aim to explore the history of Earth's deep interior in detail as an example of a habitable planet, and from that history, try to deduce the likelihood of similar histories occurring elsewhere in the Universe.NSR: So what makes our planet habitable?Xu: Among all the factors that make a planet habitable, two common substances, carbon dioxide and water, set the tone and play a central role. Our blue planet has evolved not only with the atmosphere, hydrosphere and biosphere but also with the Earth's interior. The origin and evolution of life could not exist on Earth if there were no stable atmosphere and hydrosphere. In the Solar System, the atmosphere of Venus is made up almost entirely of carbon dioxide and is 100 times thicker than that of Earth. Carbon dioxide is second only to water in its greenhouse capacity, making the Venusian surface too hot for life, reaching as high as 470oC. Life seems limited to a temperature range of −15 to about 200oC. Low temperatures cause chemicals to react slowly, interfering with the reactions necessary for life; high temperatures can break apart protein and genetic materials.Carbon dioxide plays an essential role in establishing the surface temperature of Venus. Fortunately, there is very little carbon dioxide currently in the Earth's atmosphere, while the vast majority of carbon has been locked up in the solid Earth. If all Earth's carbon were in the form of gaseous carbon dioxide, Earth's atmospheric pressure could increase by a factor of ∼100. Interestingly, this is comparable with that of Venus, implying that Earth and Venus might have started with almost the same volatile ingredients. Thus far, calcium carbonate is the largest reservoir of carbon dioxide in the Earth's crust. In general, carbonate minerals are more stable than hydrous minerals in subducting plates, and a large amount of carbon could have descended into the deep Earth. To date, the overall carbon budget related to outgassing and subduction through the interaction with Earth's interior remains to be understood.NSR: Calcium carbonate is the main component of seashells on the beach. It is interesting to know that small seashells can lock up a huge amount of carbon dioxide, preventing Earth's surface from overheating. In addition to carbon dioxide, what does water contribute to the habitability of our blue planet?Xu: Water is not as volatile as carbon. Earth-like life needs liquid water as we know it. Much organic matter contains water and undergoes transformations associated with hydration and dehydration. Remember that the human body consists of 60% water, and 71% of our planet's surface is covered by water. As a matter of fact, water might have been present prior to life on Earth and life most likely adapted to involve the abundance of water. The oldest sediments found in Greenland show that water was present as early as 3.8 billion years ago at least. Ancient zircons hold essential clues to the early presence of liquid water as far back as 4.4 billion years. Notably, changes in the sea level can be employed to delimit the surface water budget. The amount of water on the Earth's surface could have remained within a tight range over billions of years, meaning that ocean water on Earth is a balance between outgassing and ingassing water. Water–rock interactions can cause an alteration of the crust to produce water-bearing or CO2-bearing minerals. Through these volatile-rich materials’ subduction, volatiles are returned into Earth's deep interior, which balances the volcanic flux to the atmosphere.It appears that a stable climate that keeps liquid water on the surface is most important for life. It is in part determined by the physics, chemistry and dynamics of the Earth's deep interior. Ultimately, we only know a fraction of what makes our blue planet habitable; lots of mysteries are waiting to be explored and solved.Ultimately, we only know a fraction of what makes our blue planet habitable; lots of mysteries are waiting to be explored and solved.—Yi-Gang XuNSR: Answers to some of these mysteries are hidden in the depths of the Earth. Linking the Earth's internal processes and habitable environments is crucial. What key research directions do you think we should follow in the future?Xu: In order to gain a better understanding of the link between the Earth's interior processes and habitable environments, the core questions we must ask include: what is the role of early Earth processes in shaping our planet? What triggered the major geological events through Earth's history and how did these events shape our planet's evolution? How did the volatiles cycle between the Earth's interior and surface system, and what were their roles in the evolution of life? Are novel chemical reactions at depth a new sort of Earth engine? What are Earth's internal processes, and how do they govern the formation of ore deposits, volcanic eruptions and earthquakes?Details of these exciting unsolved problems will be summarized in a new book on the scientific strategy for the deep Earth sciences, which is due to be published in 2021.


Evidence-based practice in medicine and social policy relies heavily on evidence synthesis. To translate evidence into practical guidelines for low- and middle-income countries, local expertise is essential. The objectives of this study are to assess the change in capacity for conducting evidence synthesis in Africa and to identify key African institutions for regional capacity-building. We take on a network perspective, considering that the position of an institution in the African evidence ecosystem is one constituent of its research capacity.We systematically identified 3548 evidence synthesis publications between 2008 and 2019 with at least one author in Africa from the Web of Science Core Collection. These articles involved 3769 institutions. Longitudinal institution-level collaboration network data were constructed based on co-authorship information. We used social network analysis to examine the institutions’ connectivity and tendency for intra- and interregional collaboration. We also identified the degree- and betweenness-central African institutions and explored the structure and composition of their local network neighbourhoods.The number of African institutions involved in evidence synthesis has increased substantially over the last decade, from 31 in 2008 to 521 in 2019, and so has the number of evidence synthesis publications with authors in Africa. African institutions in the evidence ecosystem have also become more connected during this period. Although the amount of intercontinental collaboration continues to exceed that of regional collaboration, the tendency for African institutions to collaborate with partners in Africa is increasing. We identified seven institutions—in South Africa, Egypt and Uganda—as central to the collaboration networks between 2008 and 2019, all of whom showed a tendency to collaborate across sectors.The development of more regionally based network-building initiatives would help to foster communities of practice and inter-institutional collaboration, strengthening regional research capacity. Moreover, the analysis in this study adds depth beyond a simple bibliometric analysis and illustrates that network analysis could provide a useful tool to evaluate the effectiveness of capacity-building strategies and programmes in the future. With the dramatic increase in academic publishing rates over the past three decades, the clear synthesis of research outcomes has become increasingly important. Evidence synthesis is essential for those outside academia, as it translates results from primary studies to policy-relevant information. For example, systematic reviews can help physicians practice evidence-based medicine  and can While this proliferation of evidence synthesis has largely been driven by researchers in North America and Europe, there is a need to increase the production of evidence synthesis by researchers and institutions in low- and middle-income countries (LMICs) . KnowledThe Africa Evidence Network conducted a survey in 2017 to assess the growing capacity for evidence synthesis in Africa building on the work of Oliver et al. . They foIn Africa, significant work has been done in the past decade to orient regional policy-making toward evidence-based approaches and to lift barriers to the production and use of research evidence –13. For Connecting people is an aim many of the initiatives mentioned above share. Various global development initiatives  have established organizational networks to improve the production and uptake of evidence synthesis and communication between decision-makers and researchers. These evidence networks have been argued to create better understanding, increased capacity, and greater potential for change, and thus to lead to better decision-making . In the Collaboration networks, as measured by co-authorship on scientific papers, depict a rough image of the distribution of social capital in a research field. They have been used to study the growth in research and development of research capacity in LMICs in various areas  the collaboration network connectivity, (2) the level of collaboration of African institutions within and outside Africa, as motivated by the arguments of Boshoff , and (3)We evaluated the development of collaboration on evidence synthesis in Africa between 2008 and 2019 based on co-authorship information from published evidence syntheses that include at least one author affiliated with an African institution. Since we are interested in the development of evidence synthesis capacity of institutions over time, we chose to examine collaboration at the institutional level, rather than the author level. We used social network analysis to study the evidence synthesis collaborations, treating institutions as network nodes which are connected when they share the authorship of a paper , 25.Data were obtained from the Web of Science Core Collection. Given the proliferation of evidence synthesis methods beyond systematic reviews in the last two decades , we searThe search yielded a total of 3648 records, with 51 records removed because they had no affiliation to African countries . The final data set contains 3597 publications and includes studies across disciplinary domains. Approximately 80% of the papers are related to health sciences and medical research (as indicated by the Web of Science research area), as evidence synthesis remains primarily a method used in these fields.For each of the extracted evidence synthesis articles, we recorded the title, authors and the authors’ affiliations for analyses in the statistical software environment R (v3.6.2) . We cleaBased on the 2008 to 2019 co-authorship data, we created institutional-level collaboration networks using the igraph  package Institutions are included in all networks after their first evidence synthesis publication, as from then on we consider them part of the evidence synthesis research system. However, the 2603 institutions that published only in a single year are left out in later years, as they did not play a significant role in the research system. Leaving these institutions out does not substantially affect the results of the analyses discussed below. Forty-nine publications involving more than 20 authors were also excluded, because such collaborations likely do not reflect strong relations between institutions, and for these large collaborations, it is unclear how a publication reflects the evidence synthesis capacity of the institutions involved.After conducting a detailed, country-level analysis of the change in number of institutions involved in evidence synthesis in Africa between 2008 and 2019, and their research output in this field, we studied the evolution of the networks of collaboration on evidence synthesis.Social network analysis provides tools to examine how closely nodes in a network are connected. A detailed description of the measures discussed in this section, as well as other measures of connectivity, can be found in . To measand the average path length within the LCC is small, this indicates that the research community is strongly integrated. Moreover, to examine the influence of non-African institutions on the connectivity of African institutions, we analysed these two measures for both the collaboration networks including and excluding the non-African institutions.Note that even if a network is composed of a single component, it can still show low connectivity.E and I denote the total number of external and internal ties, respectively. In the context of this study, the E-I index is a measure for across-region collaboration. The possible values for this index range from To understand the role of intercontinental collaboration in evidence synthesis in Africa, we identified the collaborations across and within regions for the 10 networks between 2008 and 2019. We refer to collaborative ties between institutions in different regions—in this case, between African and non-African institutions—as external ties. Internal ties are collaborative ties between institutions in the same region. A classical measure of the dominance of external over internal ties (or heterophily) is the E-I index by Krackhardt and Stern , which iregionalization index. The regionalization index The E-I index is a network-level index. However, since we are primarily interested in the collaboration trends of African institutions, we here propose a group-level variation on the E-I index: the The regionalization index is an adaptation of the nationalization index of Binz, Truffer and Coenen , which dThe regionalization index has a more intuitive interpretation: it is 0 if institutions collaborate on average an equal amount with institutions within and outside Africa.v is defined ass and t, and v [v. The betweenness centrality of a node indicates to what extent it serves as a “bridge” between other nodes.To identify institutions that play an important role in the collaboration networks, we calculated the degree and betweenness centrality for all institutions. The degree centrality of a node in a network is defined as the number of edges of that node. Institutions with a high degree centrality—that is, with a large number of collaborative ties—are referred to as “hubs”. The betweenness centrality of a node h node v . The sumAlthough betweenness and degree centrality scores are often correlated (nodes with many ties have more chances to serve as a bridge), nodes with high betweenness centrality do not necessarily have high degree centrality. For example, when an institution links to one institution in each of two otherwise disconnected clusters, its degree centrality is only two, but its betweenness centrality is very high.Degree centrality and betweenness centrality are naturally dependent on network size . Given that nodes in larger networks have more opportunities for connections, the centrality scores of central nodes in large networks are likely to be larger than those of central nodes in smaller networks. Since the collaboration networks we consider here grow in size over time, we also calculated the normalized degree and betweenness centrality scores for each institution, which divide the  centrality score by the maximum centrality score possible for a node in a network with the same number of nodes.3After computing the degree and betweenness centrality scores for all institutions, we identified all African institutions that ranked top three among the African institutions in either of the centrality measures in any of the collaboration networks between 2008–2009 and 2018–2019. We refer to these institutions as the (most) central institutions and analysed how their centrality scores, as well as their numbers of publications, changed over time.Finally, we constructed the local network neighbourhoods  of the most central African institutions based on the 2018–2019 network. The local neighbourhood of an institution is composed of the collaborators of that institution, together with the ties among the collaborators. To understand the kinds of other institutions the central institutions collaborate with, we examined the region and sector  of the institutions in their local network neighbourhoods.Between 2008 and 2019, a total of 3597 evidence synthesis publications appeared, on which at least one individual from an African institution collaborated. These publications involve 4181 institutions from 154 countries. The number of institutions involved per paper ranged between 1 and 103. We excluded the 49 publications (1.4%) with more than 20 authors from further analysis   and greaWe used network analysis to delve deeper into the structure and characteristics of evidence synthesis collaboration in Africa and between African and non-African institutions. We examined the connectivity of the network over time as an indication of the flow of knowledge, expertise and resources between institutions. In addition to growing numbers of collaboration on evidence synthesis, we found increasing integration of the evidence synthesis research community, suggesting greater capacity for knowledge diffusion and resource sharing across institutions. The 2008–2009 network in Fig. To further assess the role of collaboration with non-African institutions in evidence synthesis, we used the E-I index  and propWe used network analysis to highlight institutions that hold central network positions based on both production and collaboration measures. Central institutions contribute to the stability of the network, help connect organizations on the periphery and serve as conduits of knowledge, resources and expertise . Thus, iThe consistently central position of the South African universities in this network reflects a combination of significant investment in research compared to other countries in the region , and a nCairo University and Assiut University in Egypt also held central roles in the network. However, likely due to the economic impacts of the Egyptian Revolution in 2011 , their pMakerere University in Uganda appears with a high betweenness central ranking, particularly from 2011 to 2013, indicating that it acted as a bridge between otherwise disconnected institutions. It has been found that having larger collaboration networks and collaborating with otherwise disconnected peers is correlated with more novel and highly cited research output . At an iFor central institutions in our network, we examined the diversity of sectors represented in their local collaboration networks based on collaborations in 2018–2019, as well as the degree to which they are collaborating with regional partners Fig. . Cairo UOur study relied solely on data from Web of Science. While this database provides thorough multidisciplinary coverage, it may not fully reflect the landscape of African publications, particularly those published in regional journals not indexed in mainstream databases or evidence syntheses not published in the formal peer-reviewed literature. Other databases could be searched to include broader coverage, but many insufficiently capture affiliation data for such an analysis. We also did not do an exhaustive search for all known evidence synthesis methods, but rather relied on our knowledge of the evidence synthesis publishing landscape to search for the most common forms of this type of research. We believe that the addition of other, less common evidence synthesis types would not have had much impact on the results, but this could be explored in future work.In addition, we assumed that the publication of a systematic review or other form of evidence synthesis is a reflection of the capacity of all authors for conducting evidence synthesis. While the contribution of individual authors is not known, and the quality or impact of publications was not considered, we believe our analysis should reflect overall trends at an institutional level and thus can serve as a proxy for institutional capacity.We also recognize that the current work lacks authorship-level contribution from Africa-based researchers. Thus, the results were interpreted based on the authors’ knowledge of co-authorship network analysis, and experience in collaborating on evidence synthesis with international teams and working with colleagues at African institutions to develop and conduct evidence synthesis training programmes. However, the paper lacks the expertise of those deeply familiar with the African research context. While this does not invalidate the results, it may have impacted the depth of interpretation.While we focused on institutions with high degree centrality as potential targets for capacity-building, those engaging in evidence synthesis on the periphery of the network could provide an interesting focus for future research and for investment in capacity-building programmes. Another avenue for future research is the disciplinary differences in evidence synthesis collaboration. Evidence synthesis has increased across disciplines in recent years , and capIn addition, research on the motivations and incentives for collaboration on evidence synthesis, and associated barriers, could provide greater insight for capacity-building strategies. Funders are known to drive the makeup of collaborations, for example, in requirements for interdisciplinary teams or the inclusion of top-tier research institutions , 52. GenOur study indicates that substantial opportunity exists for leveraging existing knowledge of evidence synthesis methods in African institutions and improving regional capacity. Efforts to facilitate local and regional collaborations, train domain experts and methods specialists, and increase sustained access to funding and resources should be key elements of capacity-building programmes.In the context of evidence synthesis, the incentives to publish and collaborate with researchers in the Global North likely continue to outweigh those to collaborate with researchers in other LMICs. Access to research databases and the journal content necessary to carry out comprehensive reviews in addition to funding, publishing opportunities, and high-profile research partnerships are all factors that likely influence decisions to collaborate on evidence synthesis. Despite the dominance of non-African collaborations in our network, collaborations within Africa are also increasing. We note potential for intra-African collaboration on evidence synthesis and an opportunity to build capacity from within, for evidence synthesis relevant to the African context. Initiatives that increase incentives and opportunities for regional collaboration, as well as enable access to necessary resources such as journal content and funding, would serve to strengthen the regional network and build capacity for regionally relevant evidence synthesis.We found little evidence of collaboration with government agencies in these networks. Initiatives to develop more partnerships between universities and government agencies could help inform more policy-relevant evidence synthesis. That said, stakeholder engagement may not be adequately reflected in authorship, and more research is needed to understand the role of government actors in evidence synthesis production. Moreover, further analysis would be needed to determine what is driving these differences in local collaboration networks.Oliver et al.  carried In this study, we used social network analysis to assess the changes in the network of co-authorship on evidence synthesis publications between 2008 and 2019 to shed light on the capacity of African institutions to conduct evidence syntheses and the distribution of social capital within this network. We found the collaboration network to be increasingly connected, with greater involvement of African institutions over time and increasing collaboration amongst African institutions. The network perspective on research capacity in this study revealed key roles played by institutions like Makarere University in Uganda and the University of the Witwatersrand in South Africa in bridging otherwise disconnected institutions and establishing diverse collaborations—findings a simple bibliometric analysis of publication output would have missed. This analysis also complements survey methods, which can elucidate barriers and facilitators to research capacity and highlight the role of stakeholders not reflected in publication authorship. Given the value of regional and cross-sectoral collaboration in building vibrant evidence ecosystems, network analysis could provide a useful tool to evaluate the effectiveness of capacity-building strategies and programmes in the future, as illustrated by this study.Additional file 1. Additional figure and tables.Additional file 2. Dataset.


Caring for persons with Alzheimer's disease can be an extremely difficult experience. To date, there has been a lack of research into the role of intermediary variables in the relationship between caregiver personality and psychosocial functioning. The growing numbers of dementia patients worldwide mean that more people are involved in their care, making research into this area a pressing concern. Both a caregiver's personality and personal resources play a key role in their capacity to cope with stressful situations. In order to determine how personal resources moderate the relationship between personality and burden of care, a total of 100 caregivers of Alzheimer's patients (78 women and 22 men) were asked to complete a set of questionnaires to assess personality, personal resources , as well as their levels of stress, depression, and commitment to care. Structural equation modeling and latent growth analysis suggest that personal resources explain the mechanisms underlying burden of care and moderate its relationship with personality. Our findings indicate that personal resources are a critical predictor of burden of care. Therefore, caregivers must be provided with appropriate support, taking into account their resources and personality profiles. Alzheimer's disease (AD) is a progressive, degenerative disease of the nervous system with many negative consequences. It involves cognitive and functional impairment, gradual loss of memory, and behavioral and neuropsychiatric disturbances, which together lead to a significant decline in the ability to perform routine daily activities , 2. It iExcessive engagement in caregiving leads to poorer physical health , anxietyProvision of long-term care may result in significant caregiver burden, reflected in problems with mental, physical, social, economic, and emotional functioning . ObjectiPersonality seems to play a central role in caregiver burden. Caregivers with less mature personality types, especially high neuroticism, have been shown to be at higher risk of experiencing severe caregiver burden –23. TherDue to the key role of caregivers in the provision of care, it seems of paramount importance to examine factors that may protect against caregiver burden. Previous studies have indicated that sense of coherence (SOC) plays a significant role in alleviating caregiver burden and preventing the development of depressive symptoms –40. OtheThe exact relationships between personal resources and caregiver burden is poorly understood. Among personal resources, social support seems to play a particularly significant role in shaping the sense of burden and the development of depressive symptoms –48. Howevia an individual's conviction about their capacity to act, promotes better coping . We conducted home visits  and institutional visits  that included established demographic interviews and questionnaire sets provided in the same order. The study was conducted according to the guidelines of the Declaration of Helsinki, and approved by the Ethics Committee of Institute of Psychology at University of Szczecin (KB 2/2017). All participants gave written informed consent. Participation in the study was voluntary, confidential, and the personal well-being of the respondents was of utmost importance. Significant inclusion criteria were: having been a carer for a minimum of 2 years and providing at least 8 h of care per week to a patient with Alzheimer's disease. Exclusion criteria were provision of care to a patient with a different type of dementia, death of the patient, and the caregiver being under 18 years old.M = 28.82 (SD = 6.39) hours a week, and whose mean age was M = 55.84 (SD = 13.36) and total duration of care was M = 5.18 years (SD = 4.25). Most respondents (58%) devoted >32 h a week to caring for AD patients, 28% spent 17-32 h, and 14% spent 8-16 h caring. A total of 37 of the AD patients being cared for were in the first stage of the disease, 44 were in the second stage, and 19 were in the third stage of the disease. We defined the stages of AD based on , including 78 women and 22 men, who provided care for based on . The priTo meet our research aims, we selected the relatively more significant personal resources and factors related to caregiver burden: sense of coherence, perceived social support, and generalized sense of self-efficacy. To assess the personality traits of the caregivers, we used the NEO Personality Inventory (NEO-PI-R) . This isr correlation coefficient was used to establish the relationships between the investigated variables (testing the first hypothesis). Correlation analysis was performed with the GNU PSPP-0.10.1-gbe241b program. Partial least squares structural equation modeling (PLS-SEM) in the WarpPLS 6.0 0 program , experience less tension in their relationships with care recipients, are less likely to control their functioning, and more likely to foster their independence. According to the theory of salutogenesis , the avaThe results of our research also demonstrated that an increase in SOC led to weaker relationships between extroversion and guilt and anxious tension and stronger relationships between extroversion and decreased psychosomatic symptoms, tension in relationships with care recipients, supervision, and urging. We also observed that with increased SOC, openness to experience was more associated with a decrease in psychosomatic symptoms, supervision, and all investigated types of stress. In addition, it was more closely linked with increased tension in relations with care recipients and worrying. Furthermore, we found that an increase in SOC was linked to a greater association between conscientiousness and decreased cognitive deficits and thinking about death. Our results are consistent with previous reports, highlighting the key role of SOC in reducing the sense of burden , 42, depThe nature of the relationship between caregiver personality and burden of care is also explained by the moderating effect of perceived social support. We found increased perceived social support to be linked to neuroticism having a stronger relationship with decreased thinking about death and increased guilt and anxious tension. At the same time, it had a weaker relationship with increased psychosomatic symptoms, tension in relations with the patient, worrying, supervision, and urging. On the other hand, increased perceived social support resulted in extroversion having a stronger relationship with decreased psychosomatic symptoms and tension in relations with the patient, as well as increased supervision, and its having a weaker relationship with decreased guilt. Perceived social support also moderated the relationship between openness to experience and conscientiousness and the investigated dimensions of caregiver burden. Openness to experience was more associated with a decrease in psychosomatic symptoms and supervision, as well as an increase in tension in relationships with the patient, worrying, urging, and external and intrapsychic stress. Conscientiousness, on the other hand, was more closely related to decreased thinking about death and increased worrying and urging. At the same time, it was less associated with decreased emotional tension. Previous studies indicate a significant role of social support in reducing care-related stress , 92, 93,The nature of the relationship between caregiver personality and burden of care is also explained by the analyses of the moderating effect of generalized sense of self-efficacy. Our research showed that with increased generalized sense of self-efficacy, neuroticism had a stronger relationship with increased cognitive deficits and decreased thinking about death. We also found extroversion to have a stronger relationship with increased supervision, while agreeableness had a weaker relationship with decreased thinking about death, guilt, and supervision. Along with the increase in self-efficacy, conscientiousness was less related to the increase in tension in relations with the patient and supervision, and more related to decreased cognitive deficits. Studies to date indicate a significant role of self-efficacy in reducing sense of burden –57, 87 aThus, personal resources play an important role in moderating the relationship between personality and burden of care. However, their moderating effects in the studied sample are rather diverse. Our research indicates that personality has both a direct and indirect effect on caregiver burden, in the latter case involving personal resources. Hence, to improve caregivers' functioning and reduce their perceived burden of care, it is essential to take into account their personality traits and the repertoire of personal resources they have at their disposal.This study had several strengths and limitations. First of all, a major limitation is its relatively small sample size. Further research could include larger groups. Nevertheless, this research provokes reflection on the factors that could play a significant role in improving the psychosocial functioning of caregivers. Studies to date tend to focus mainly on the negative consequences of providing care, therefore it seems all the more necessary for further research to shed light on the role of resources in reducing the sense of burden. In the future, this aspect of caregivers' functioning should be addressed using a larger group of respondents. Another important limitation is the relatively small number of male carers. Previous studies show that it is women rather than men who tend to provide care and are mainly responsible for ill persons –97. It tDespite these limitations, the study also had several strengths. First of all, to the best of our knowledge, this study is one of the few that have considered the role of personality components in the development of caregiver burden. One of its major strengths is therefore its approach toward personal resources as important determinants of the relationship between caregiver personality and burden, thus helping to identify factors that can transform or prevent negative consequences of care.Our findings shed further light on the factors that may be construed as critical in shaping perceived burden of care. The results of this study could prove useful for both psychological practice and psychoeducation. Furthermore, this study suggests that the caregiver's personality and personal resources should be considered when developing assistance programs. Proper assessment of a caregiver's personality and personal resources could help identify the most significant contributors to subjective feeling of burden.This study provides evidence that carers with less mature personality types are more likely to be burdened with care, thus confirming the key role of personality components in caregiver burden. In addition, personal resources are an important predictor of burden of care. The nature of the relationship between personality and perceived burden depends on levels of personal resources. Therefore, it seems crucial to properly support caregivers and strengthen their resources. This may have implications for future research. Proper assessment of resources and personality should be an important goal for all psychotherapeutic activities. Identification of the factors that make one vulnerable to increased burden can help in the selection of the most suitable strategies for coping with the demands of care. Therefore, to protect the caregiver against depression and reduce their stress and burden, it seems of utmost importance to undertake all the necessary measures to rebuild or recover any resources that might have been lost or depleted. Such actions can also protect against premature institutionalization of patients. Individual caregiver personality profiles and assessment of personal resources could improve the provision of effective aid to carers.The datasets generated for this study are available on request to the corresponding author.The studies involving human participants were reviewed and approved by Ethics Committee of Institute of Psychology at University of Szczecin (KB 2/2017). The patients/participants provided their written informed consent to participate in this study.AS was the coordinator of the project, was involved in the study design, took part in recruitment of the participants, conducted research, managed the literature searches and analyses, performed the statistical analysis, and wrote the first draft of the manuscript. MB was involved in the study design, was a supervisor, and corrected the manuscript. ET was involved in the study design, took part in recruitment of the participants, managed the literature searches and analyses, performed the statistical analysis, and wrote the first draft of the manuscript. All authors contributed to and have approved the final manuscript.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


The interest in implementing digital pathology (DP) workflows to obtain whole slide image (WSI) files for diagnostic purposes has increased in the last few years. The increasing performance of technical components and the Food and Drug Administration (FDA) approval of systems for primary diagnosis led to increased interest in applying DP workflows. However, despite this revolutionary transition, real world data suggest that a fully digital approach to the histological workflow has been implemented in only a minority of pathology laboratories. The objective of this study is to facilitate the implementation of DP workflows in pathology laboratories, helping those involved in this process of transformation to identify: (a) the scope and the boundaries of the DP transformation; (b) how to introduce automation to reduce errors; (c) how to introduce appropriate quality control to guarantee the safety of the process and (d) the hardware and software needed to implement DP systems inside the pathology laboratory. The European Society of Digital and Integrative Pathology (ESDIP) provided consensus-based recommendations developed through discussion among members of the Scientific Committee. The recommendations are thus based on the expertise of the panel members and on the agreement obtained after virtual meetings. Prior to publication, the recommendations were reviewed by members of the ESDIP Board. The recommendations comprehensively cover every step of the implementation of the digital workflow in the anatomic pathology department, emphasizing the importance of interoperability, automation and tracking of the entire process before the introduction of a scanning facility. Compared to the available national and international guidelines, the present document represents a practical, handy reference for the correct implementation of the digital workflow in Europe. The interest in implementing digital pathology (DP) workflows to obtain whole slide image (WSI) files for diagnostic purposes has increased in the last few years. This is due to the opportunities offered by WSI, e.g., telepathology and image analysis, including computational pathology tools based on artificial intelligence [AI] methods. The increasing performance of technical components and the Food and Drug Administration (FDA) approval of systems for primary diagnosis  led to iSo far, there are several possibilities to transit and to manage “images” in a digital workflow: an LIS-based approach ,13, a scBox 1SummaryDigital pathology is pathology—A holistic approach that comprehends interventions in all stations of work at the pathology laboratory, introducing innovation.Digital pathology is attractive and convenient for pathology laboratories worldwide.Digital pathology represents a safer and more efficient way of working and should be considered the new standard in pathology.Implementation of a digital pathology workflow is the milestone to fully benefit from the potential of WSI and a prerequisite for the application of AI in routine diagnostics.The implementation of digital pathology requires a multidisciplinary approach from the very beginning. The leading team should involve in-house participants  and the hospital’s IT and technical services . IT servIn a fully digital laboratory, the processes and records are electronic file-based, the environment is paperless, with glass slides being substituted at the end of the workflow by WSIs. The optimization of resources, namely time, space, people and instruments, creates conditions for increased efficiency and, consequently, decreased costs. The LEAN approach represents a valuable strategy to optimize the workflow, leading to a more logical distribution of the spaces to minimize staff and sample traffic inside the laboratory. It also allows for a more harmonic and well-planned articulation between human resources and available instruments, which results in time and cost-effectiveness. Although it is not a strict prerequisite for adopting DP, it could further allow for better allocation of resources . This caIndependently of the system employed to manage the WSI , pathology laboratories mainly depend on laboratory information systems (LISs) to support their operations and, ultimately, carry out their patient care mission. For these reasons, one of the crucial points is to ensure the full integration of the systems involved in the digital transition. Although many LISs have evolved with sophisticated and more user-friendly software over the past few decades, supporting a broader range of functions, many others have not evolved, thus preventing possible integration with other technologies deployed in the laboratories. Modern LISs play different roles in all phases of patient testing, including specimen and test order entry, specimen processing and tracking. They track and organize the laboratory’s workflow, mainly through event logs and histology protocols. The maintenance of such logs can follow the default configurations of the system or can be customized by each laboratory to display the most useful information. A typical example of the system’s default configuration for a log  includes accession number, timestamp, patient and specimen data, histology protocol(s) ordered, other stains ordered and comments about the specimen or the request. LISs now incorporate multiple features that, until recently, were either unavailable or required a significant customization effort to be obtained. The Association for Pathology Informatics produced a comprehensive list of basic and advanced LIS features that may be used to evaluate LIS capabilities . MoreoveAutomation and using a robust tracking system can significantly reduce errors related to handwriting transcription and misspelling that can cause samples to be dissociated from a particular patient (“mismatching”). Automation is a “strong recommendation” emanating from these recommendations, as it can benefit both pathology laboratories using DP and those using glass slides for diagnosis. Besides the introduction of a suitable LIS/LIMS that can help monitor the instruments’ performance connected to each sample, further automation can be introduced in the workstations. This includes the reagents used and tracking all the staff that were at any point involved in sample processing by differential log-ins or scanning of individual ID codes at all workstations. The possible automation of workstations obviously depends on budget, existing instruments, and the experience of the technical staff. Devices such as a robotic stainer and a cover-slipper will bring consistent slide quality, avoiding frequent re-staining and ongoing readjustments to scanning protocols. The same is true for the automation of embedding and cutting processes, for which available systems on the market appear promising. However, these are not yet widely used in practice . The goaAs will be further explained in the following sections of this paper, the use of unequivocal 2D barcodes can have many applications in the proposed digital workflow, significantly reducing the operations time and error rates. The impact of such implementation can be noted starting from the accessioning phases, where the sample is assigned its unequivocal code that will be used later during the processing and reporting steps. This can further help in the creation of tissue cassettes, the production of glass slides, automatic requests for additional histologic and IHC stains, as well as in the double-check that should be carried out at every checkpoint to ensure the correspondence among arrived material, grossed specimen, embedded sample and cut sections. This is facilitated by the additional use of barcode readers and by implementing instruments capable of capturing the cut surface directly from the paraffin block see .Quality control of products from a pathology laboratory is essential to guarantee that a patient receives a correct diagnosis. In Europe, the certification and accreditation of laboratories are not equally and uniformly performed across the territory. Instead, many laboratories design their own quality control program, more or less simplified, often involving only segments of sample processing adequate to their intent. Although adopting a quality management system is not strictly required in all countries as a prerequisite for implementing DP workflow, laboratories with a robust system of quality management may find the DP workflow easier to implement as they are already aware of the critical control checkpoints through the analogue workflow. To support those laboratories that are not yet familiar with quality control programs, a detailed description of some suggested checkpoints suitable for adaptation to each laboratory are provided. The checkpoints described here derive from the need to control the performance of a new instrument in the pipeline—the scanner. They also originate from introducing new standard operative procedures (SOPs), tools/instruments and quality control of the processes .Simultaneously, per each workstation, some technical modifications are discussed to facilitate the scanning process and increase the quality of the WSI. We highlight that time loss within the laboratory is frequently motivated by a mismatch of samples and poor sample quality . Investing in a workflow with a good quality of samples that are easy to track decreases the time lost, considering that this loss is very difficult to estimate because it is not generally recorded.Patient IDC IDSpecimen container ID (entry lab)Sample IDsBlock IDsSlide IDsDuring the accessioning phase, samples that arrive at the pathology laboratory are registered in the LIS and given a case number. Analyzing the classical analog accessioning procedures allows for a critical evaluation of the potential issues that can and do happen. Mistakes can occur in the compilation of paper requests from the submitting department or outside hospital . The staff responsible for the accessioning phase can miss discrepancies between the sample/slide and the request or even mismatch this pair. The manual insertion of the specimen/patient data into the LIS can impair the link with the patient profile present in the hospital information system (HIS), generally due to an inappropriate transcription of a patient’s identification data, eventually causing a duplication of patients’ profile, and consuming time. In a laboratory with a DP workflow, laboratory personnel have the possibility of completing these accessioning tasks automatically to minimize the risk of errors. The different identification codes (IDs) used in the various subsequent steps play a crucial role here. Similar to a pyramid or hierarchy, different types of IDs are attributed to the patient, and everything associated with this accessioning event, as follows:Sample/slides arrive in the pathology laboratory with a label containing a code  associated with patient and case data.By scanning the code on the label of the case, the administrative is able to open the digital request on pathology LIS automatically, allowing the automatic synchronization of the information from the hospital system or creating the specific page for cases/patients coming from outside.A case ID for the sample is generated.The case ID is then used in all sorts of assets generated for that case .The administrator can take pictures of both the container and the specimen, and these photos will be attached to the case file.All of the documents received together with the specimen are scanned and attached to the case file or directly transmitted to the LIS digitally .For DP, a mechanism is needed to get the following types of required case information to the administrative and the pathologist: patient ID and demographic information, description of the specimen, clinical history and questions or requests for the pathologist. In the digital pathology laboratory, the accessioning is modified and may include some or all of the following : Sample/After accessioning, cases are ready to be macroscopically analyzed, described and grossed by the pathologist or trained technical staff. As this happens in accessioning, the grossing workstation may be a source of human errors. These errors may include some of the following: wrong assignment of the macroscopic description and grossing of one patient in the paperwork of another patient, loss of manual transcription of specimen descriptions, deterioration of the numbers on the cassettes and incongruences among the sample received, grossed and subsequently processed in the absence of step-by-step picture documentation.The grossing operator  can access the case/patient file by directly scanning the code on the sample container.Pictures are taken of the sample before it is described and grossed, as well as during grossing, and finally of all tissue cassettes with slices; those images are directly linked to the case using the software integration paths between the LIS and the image capture instrument.The grossing operator performs a macroscopic description of the sample through automated speech recognition systems that report the text in the appropriate section of the case/patient file using the software integrations paths between the LIS and the dictation system instrument.The operator can produce cassettes by using a specific printer (preferably laser printer) to assign an identification code corresponding to the particular case, as established during the accessioning and using the software integration paths between the LIS and the printer. The cassettes and marker media should be appropriately tested to demonstrate the indelibility or impossibility of washing away or removing the identification code. The suggested code is 2D , which can include a greater character count (higher data density), require a smaller footprint, and have fewer scan and printer failures than 1D codes.An image of the cassette with the grossed specimen should be obtained at the bench, allowing retrieval of this at the following steps.As in the other workstations, through automation the DP workflow can help reduce to a minimum the human interference needed in the grossing phase. The previously described process would be as follows : The groAfter the grossing phase, cassettes containing the specimens are ready to be processed. At this stage, further checkpoints may be needed to verify that all the cassettes generated at the grossing workstation are present in the rack to be processed. This double-check is still routinely and primarily done manually in most pathology laboratories. In a DP workflow, this task may be carried out by scanning the codes printed in the cassettes of the rack before they are processed and checking if all the produced cassettes are submitted to the subsequent phase, integrating the information in the LIS. During the processing phase, both the instruments and programs used should be preferentially recorded through the employment of an appropriately integrated LIS, allowing for tracking the specimens/cases at this workstation. This system can be further deployed to track the usage of reagents for processing, helping in the safe disposal of these reagents. Moreover, the integration with the LIS can further help aggregate specimens and cassettes in different racks based on their processing time and scanner time/protocol requirements , or even separate specimens processed in different instruments.Once the processed specimen inside the cassettes have arrived at the embedding room, operators (technicians) should be able to access the pictures taken during the grossing phase by simply scanning the barcode . This wiThe sectioning workstation is a time-consuming phase of the laboratory flow where errors are frequent. Here, the automation can facilitate the technician’s work bringing increased control, fewer errors, and resulting in less time spent. The sectioning workstation is complex and requires the rapid manipulation of specimens and instruments in a consecutive way. The introduction of a slide printer, a code reader, a desktop interface, and similar devices can be initially perceived as a further complication of this step. Checkpoints can be installed at this workstation depending on the laboratory’s needs and may prevent important errors . MoreoveOnce in the staining workstation, the slides produced in the digital workflow are identified through their code to define which staining protocol they should follow, as per internal LIS prerecorded indications, using automated staining platforms. As in the previous step, the staining process should follow the highest qualitative standards to reduce possible modifications that can interfere with the scanning phase . For this purpose, implementing an internal checkpoint with daily controls and/or external quality control can help assess the quality of stained slides . AutomatPlease refer to After the sectioning and scanning phases, blocks and slides can be appropriately archived to be retrieved whenever is necessary. This task has been historically performed manually by operators (technicians or laboratory assistants), leading to loss and misplacement of blocks/slides, with obvious medico-legal consequences. Moreover, the wide practice of consulting archival material by all the laboratory workers, including residents and students for didactic purposes, can further complicate the correct positioning of these specimens. Based on these observations, the full integration with the LIS and the presence of unique identifiers, both on the blocks and glass slides, allow an automated archiving of all the biological material, as well as its safe and unbiased retrieval if needed . For archiving of the WSI, please refer to the data retention policy . The following section focuses on the possible impact of such a choice on DP workflow implementation. According to the LEAN approach, as previously stated in chapter 2, the positioning of the scanners should follow the logic of an automated workflow and thus be placed as close as possible to the staining and cover-slipping stations, making their implementation in the entire process easier and smooth ,7. The tThe scanning process.Virtual slide quality control.However, a few comments are needed. Overall, scanning during working hours should be preferred for practical and logistical reasons. If there are problems with the scanning process, it might be better to avoid scanning after working hours. For example, it has been reported that the mean scanning time in a routine environment is about 6 min for scanning a slide at an equivalent of 40 × magnification . TherefoThe first part mainly consists of loading/unloading slides in the scanner and taking snapshots to ensure that the instrument captures all the material on the glass. On the other hand, the quality control phase is equally important and may be time-consuming, encompassing all the quality check procedures of the final WSI and related data. The points discussed above pertain to “regular” scanners for bright field microscopy. Other “special” scanners exist, e.g., those for dark field microscopy , as well as those for whole mount slides (macro slides). Because of their highly specific fields of application , they arSeveral validation studies for WSI have been published, and most show broad concordance between the conventional microscope and the digital diagnosis ,36. RegaThis path for the implementation of WSI for primary diagnosis has been followed by different laboratories worldwide ,37,38. S2). Some FDA-approved built-in solutions for digital pathology employ medical-grade displays. However, the minimum requirements for DP monitors are still debated, and there is no consensus on how to assess their quality. External sources of variability further complicate this matter, such as the distance from the monitor and the illumination conditions of the room, which makes unbiased comparisons among the different devices available more difficult. This heterogeneity, and the large variety of supply in the digital market, has been recently reviewed [The typical pathologist workstation is composed of one computer and two monitors. One monitor displays the LIS showing patient data and different dashboards with the possibility to access the patient’s documents or slides. The other monitor is dedicated to the visualization of the WSIs or other images. Several documents have already described all of the features needed to implement the visualization instruments in DP, namely, monitor quality, brightness and contrast, color depth, fidelity and profiles ,41. Manyreviewed . Many coAfter digitization, the produced WSI should be checked to ensure appropriate image quality to avoid any technical interference with the final diagnosis. Although most of the routine slides (about 90%), if properly processed, should not present scanning problems, some special slides  would benefit from dedicated scanning protocols and could be affected by more digitization issues. On the other hand, a minority of the “routine” slides (about 10%) could still be affected by scanning issues, stressing the need to adopt alternative protocols to obtain WSI from these challenging samples. This is based mainly on the assessment of focus quality, which can be partly assisted by the automated metric implemented in some available scan systems but should be performed on every slide to decide whether to rescan the sample. This can be done systematically by the lab personnel  for every scanning set before assigning the case to a pathologist. Alternatively, the pathologist can perform this check once after case review, requesting a rescan of a glass slide similar to the way that an additional recut or a special stain is ordered in the LIS. However, under real-life conditions, the entire manual check could be rather time-consuming and troublesome, especially in light of the need for subsequent deployment of image analysis algorithms. For this reason, automation of this phase is highly recommended. It can further speed up the digital transition process, ensuring an adequate quality of the scanned slide for potential subsequent AI analyses . SupposeA critical assumption with using WSI in clinical settings is that scanned slides are completely accurate digital representations of glass slides. Therefore, it is of paramount importance that all tissue fragments present on glass slides be recognized and captured for review on the resulting digital slides.The overview (rendering the macro/slide label files) that is a low-resolution snapshot of the entire glass slide.The “digital image” of the glass slide generated by a microscope camera  often acquired at the chosen magnification.Typically, two main different images are generated during the digitization process:Many WSI devices include systems to detect tissue samples on a slide to limit scanning to relevant tissue-containing areas. For example, some scanners are programmed to omit the blank areas on the slide during the scanning process, where tissue is presumed to be absent, to speed up the process and generate files of smaller size. However, sometimes the tissue detection mechanism can fail to identify small or pale pieces of tissue automatically , or the user may not appropriately select the region containing the entire tissue analyzable. This may lead to potential errors that can cause serious discrepancies between the tissue present on the glass slide and the WSI. In this setting, overview images can help avoid such errors and represent a valuable tool for quality assessment purposes . The macOther possible sources of tissue coverage errors can result from inappropriate placement of tissue sections on the glass slide , which can fall outside the area recognized by the scanner. To address this issue, it is also essential to check the technical specifications of the scanner, specifically regarding the predefined detectable area that could be insufficient to cover the entirety of the physical glass slide containing tissue. These issues can be addressed by following the point-by-point indications reported above on the sectioning and cover-slipping checkpoints. Finally, very few cases with concordant WSI and macro images can still hide discrepancy issues with the entire amount of tissue sent for the analysis in the lab. This could be addressed by the manual, analog comparison of the tissue block with the macro images and the WSI, as suggested in the relative checkpoint in At the end of the scanning process, one of the most important steps is correctly assigning the digitized slides to the appropriate case/patient. As already mentioned, during the scanning phase a macro image is generated representing a snapshot of the entire glass slide that usually includes the slide label with identifiers . As per other steps mentioned in Data retention policies and image storage solutions for WSIs still represent open and debated topics, and no strict recommendations have been provided yet, although some suggestions and indications can be found in different documents and guidelines . GeneralClosely related to the retention policy is the appropriate storage of the images: where, how, and which slides must be stored is still an unresolved issue with multiple possibilities that can be adapted to each laboratory’s needs. Regarding the solutions available on the actual storage of the WSIs, organized and redundant storage solutions  are preferred to simple external/internal hard drives, considered negligent by some authors . The posIt has to be underlined that digital pathology storages need to be built to be interoperable and useful. This requires high-quality datasets, seamless communication across IT systems and standard data formats . InteropThe process of DP implementation has designs and consequences that are distinct in each pathology laboratory. Monitoring the effects of the digital transformation of the laboratory is good practice. It may include an analysis of the following parameters before and after the implementation: results of quality control, turn-around time, workload for technicians and pathologists, ergonomics of each workstation, and the general satisfaction of the staff. For validation and quality control of the implemented digital workflow, we direct the reader to the recommendations already in use ,33,40.Having a digital repository that contains clinical and histological information can lay the foundation for using numerous computational pathology tools. The application of image analysis algorithms can allow the identification of specific cell or tissue compartments  for quantification  as well as for classification purposes  . Some prThe present recommendations represent a European guidance for transitioning from a classic, “analogue” to a completely digital workflow in every anatomic pathology department. Ten basic principles  resulted