Technologies are expected to help older adults age in place, yet little empirical research is available on how seniors develop a need for technologies, how they acquire these technologies, and how these subsequently affect their lives. Aging is complex, dynamic and personal. But how does this translate to seniors’ adoption and acceptance of technology? To better understand origins and consequences of technology acquirement by independent-living seniors, an explorative longitudinal qualitative field study was set up.Living independently can be challenging for seniorsHome visits were made to 33 community-dwelling seniors living in the Netherlands, on three occasions (2012–2014). Semi-structured interviews were conducted on the timeline of acquirements, and people and factors involved in acquirements. Additionally, participants were interviewed on experiences in using technologies since acquirement. Thematic analysis was employed to analyze interview transcripts, using a realist approach to better understand the contexts, mechanisms and outcomes of technology acquirements.Findings were accumulated in a new conceptual model: The Cycle of Technology Acquirement by Independent-Living Seniors (C-TAILS), which provides an integrative perspective on why and how technologies are acquired, and why these may or may not prove to be appropriate and effective, considering an independent-living senior’s needs and circumstances at a given point in time. We found that externally driven and purely desire-driven acquirements led to a higher risk of suboptimal use and low levels of need satisfaction.Technology acquirement by independent-living seniors may be best characterized as a heterogeneous process with many different origins, pathways and consequences. Furthermore, technologies that are acquired in ways that are not congruent with seniors’ personal needs and circumstances run a higher risk of proving to be ineffective or inappropriate. Yet, these needs and circumstances are subject to change, and the C-TAILS model can be employed to better understand contexts and mechanisms that come into play. For years, my suggestion that my mother should get a tablet has fallen on deaf ears. Then, her trusty old PC broke, a friend sang the praises of her own tablet, and the next thing I know, she is Facetiming me.” [ing me.” “The generation that tech forgot” [Older adults are often considered ‘laggards’ and ‘resistant’ when it comes to acquiring technology , 3. Yet, forgot”  demonstr forgot” –6. What Understanding the origins and consequences of seniors’ acquirement of technology is important from both a healthcare (demand) and a business (supply) perspective. All around the world the number of older adults is increasing. In the more developed regions, 24% of the population is already aged 60 years or over, and that proportion is projected to reach 29% in 2030 and 33% in 2050 . Globall“complex issue that is affected by multiple factors” [interplay and dynamics between factors is very limited. As noted by others, we still do not know very much about when, how and why community-dwelling older adults acquire technology [From a business perspective, the older consumer market has, in general, long been considered uninteresting and irrelevant –18. Howefactors” . Severalfactors” , 26, 27.chnology , 28–31. chnology , 30, 32.Previous research among seniors points to several aspects that need to be taken into account, when aiming to understand the origins and consequences of their technology acquirements. First, the older adult population is highly heterogeneous –35. WithThe current study aimed to understand the origins and consequences of technology acquirement by independent-living older adults. We did this by exploring: (1) how and why technologies are acquired by independent-living older adults; and (2) the implications of the ways in which independent-living older adults acquire technologies. In this pursuit, we appreciated that older adults are diverse, that their lives are subject to change, and that their acquirement of technology may be influenced by their family and friends.t1, t2, and t3; 2012–2014). The Ethics Review Board of the Tilburg School of Social and Behavioral Sciences approved the study.To capture both the origins and consequences of technology acquirement, a prospective and explorative longitudinal qualitative field study was carried out –45, whicN = 53, t1). Over the course of the study subsequently 18 and 2 participants dropped out . Reasons for drop out were: not interested in continuing (n = 5), deceased (n = 4), somatic health problems (n = 4), cognitive impairment (n = 2), too busy providing informal care for their partner (n = 2), no longer living independently (n = 2), and lost contact (n = 1). For the study reported here, only individuals who participated in t1, t2 and t3 were included (N = 33).In 2012, a purposive sample of independent-living older adults with different health statuses, living arrangements, and levels of technology experience was recruited. Sources of recruitment were home care providers, a senior volunteer organization, a local tablet computer pilot project, a local shopping center, and word of mouth contacts. Inclusion criteria were: (1) independently living at home, (2) aged 70 or older, (3) Dutch nationality, and (4) no cognitive impairment as measured by the Mini-Mental State Examination (MMSE)  using a t1), informed consent was acquired. Prior to the second and third visit , participants were informed by letter on the research project’s progress, and participants were called to schedule a home visit at their convenience. Home visits were performed by pairs of researchers .At the beginning of the first visit (t1 (September – December 2012) was to understand participants’ lives, and their perceptions and attitudes towards technologies.The aim of the data collection at For this purpose, we performed three types of data collection: (1) background information on educational level, civil status, living arrangement, level of formal and informal care, chronic conditions, subjective health status, frailty as measured by the Tilburg Frailty Indicator (TFI) , and cogt2 (May – July 2013) and t3 (March – June 2014) data collection was aimed at understanding why participants acquired new devices since t1, and at investigating participants’ experiences with new devices after acquirement. First, the same type of background information on participants as in t1 was gathered. Secondly, participants were asked whether they had acquired electronic devices since the last visit. We recorded the date on which each new device was acquired, and the frequency of use at the time of the visit. Lastly, a semi-structured interview on the acquirement of devices was conducted. We were particularly interested in understanding the timeline of acquirements, and the people and factors involved in acquirements. Additionally, participants were interviewed on their experiences in using devices since acquirement, focusing on their satisfaction with the device, and the implications of using it. When a participant had acquired many devices, we selected a number of devices to discuss, aiming to include various types. During the interviews, we took into account the background information that was gathered on each participant, and relevant themes which had emerged in previous interviews with the participant. The topic list used in the interviews was based on the topic list used at t1, and evolved as data collection progressed. In this stage of the data collection, we made sure that at least one of the two visiting researchers had visited the participant before. All interviews were audiotaped and transcribed verbatim by a professional transcription service.At t1 transcripts, two-thirds of the t2 transcripts, and one-third of the t3 transcripts were first coded independently by two different researchers from the pool of six . We aimed to have transcripts analyzed by a researcher who was present at the interview, and a researcher who was not, to fuel discussion. The two researchers discussed their analyses, and produced a single coded version of each transcript. Periodically, these coded transcripts were combined into one Atlas.ti file by SP. This file was used in group sessions in which new codes were discussed, and overarching themes of codes were formed. Soon after the analysis of the t1 transcripts, few new codes were added, which indicated that data saturation was reached with regards to which factors and themes had influenced ownership and level of use of technology. However, in order to understand the dynamics and interplay between these factors and themes over time, an additional phase of data analysis was necessary.Qualitative analysis of transcripts entailed two phases. In the first phase, thematic analysis , 50 was “When a spark is introduced to gun powder, the chemical composition of gun powder (mechanism) results in an explosion (outcome). However, there are no explosions if the context is not right—damp conditions, insufficient powder, not adequately compact, no oxygen present, duration of heat applied is too short (context)” [In phase two of the analysis, the dynamics and interplay between factors and themes were analyzed by SP, KL, HV and EW, using a realist approach , 52. Cenontext)” . The reaontext)” , 55. As ontext)” , systemat1, t2 and t3. On one occasion, a participant felt she was misinterpreted during an interview. This was discussed with the participant, and taken into account during data analysis. On all other accounts, participants had no remarks with regards to the summaries.Member checking took place in two ways. First, in order to promote descriptive and interpretative validity , a summan = 3), deceased (n = 3), and lost contact (n = 2). All participants recognized themselves very well in our descriptions of them and their acquirements of technology. Participants would sometimes add specifics that were in line with our analysis. These were recorded, but did not alter our conclusions.Second, as an additional step, extra home visits were made to participants in June and July 2015. The goal here was to promote theoretical validity , and theIn the following paragraphs, we first describe the characteristics of the sample. Next, we describe the origins  and consequences  of technology acquirements by participants. In our description of the origins of technology acquirement, we discern between the status quo of participants prior to acquirement, decisive developments within that status quo, and acquirement enabling mechanisms. In the last two paragraphs, we describe the number and types of acquirements by participants, and favorable and unfavorable consequences of technology acquirements. In the discussion section, a new conceptual model that captures the aforementioned is presented.t3. The participants’ frailty (TFI) score, which potentially could range between 1 and 15, was lowest at t2, and highest at t3. The participants’ cognitive functioning (MMSE) score, which potentially could range between 0 and 30, remained stable around 28, indicating normal cognitive functioning among participants.The sample consisted of 33 participants who were aged in their seventies and early eighties Table . There wt1 . For participants, wanting to remain independent not only implied being able to look after oneself, but also experiencing freedom to do what you want to do, and not feeling ‘in debt’ towards others such as family members, for example by asking them for help. Concerning the above-mentioned needs, a considerable amount of variation was noticed among participants. First, some participants displayed urgent concerns with regards to meeting experienced or expected challenges, while others mainly linked challenges to other older adults who were ‘worse off’ than they were. Second, while some participants spoke about various needs, other participants’ discussions of needs were restricted to one or two needs that were central to them, and very much on the foreground .Participants mentioned various experienced and/or expected challenges related to living independently. More specifically, participants in various degrees mentioned how important it was for them to stay active, healthy, connected, mobile, independent and/or safe. The need to stay active could entail a number of activities, varying from being able to do housework, to being active in voluntary work. The need to stay connected included the need for social contact with others, but also the need to I find my landline phone convenient… I do not want two… A mobile phone and a landline phone, that is too much for me” (P3). Moreover, the use of technological means competed with the use of non-technological means, for example hiring a housekeeper instead of using a vacuum cleaner, or asking relatives to look something up online in order to avoid personally using a computer. The number and type of means available were dependent on each participant’s specific context. In some cases, participants expressed to be forced to use a technological mean that they were not satisfied with, because they had no alternative.In order to meet their challenges in the domain of independent living, participants employed non-technological and/or technological means . Technological means used by participants included assistive devices , home and personal care appliances , home automation devices , home fitness equipment , ICT devices , telephones , and transportation devices . These technological means were used to various extents by participants. Some devices were part of participants’ routines, while other devices were owned but used sub optimally, as was often the case with for example personal alarm buttons and fitness equipment. Additionally, the use of technological means regularly competed with the use of other technological means: “Analysis showed that through interacting with technological means, participants had formed internal technology related schemas and attitudes. Participants’ technology related schemas contained three sets of beliefs. The first set of beliefs was concerned with the properties of technological means. For example, participants had favorable or unfavorable beliefs concerning the reliability, lifespan, power consumption, and costs of purchase and maintenance of technological means. The second set of beliefs entailed the perceived consequences of using a technological mean. These could involve consequences for the participant as well as consequences for others such as relatives. In many cases, participants perceived both positive and negative consequences of using technological means. For example, for a male participant living alone, using a microwave oven meant that he could remain independent because it allowed him to cook his own meals. At the same time, the fact that he could use a microwave also implicated that his children did not invite him as much for dinner as he would like to. Additionally, many participants did not want to start using assistive technology because they anticipated it would make them appear old or frail (a negative consequence). The third and last set of beliefs was concerned with participants’ self-efficacy in using technological means. Participants frequently made references to their (in)ability to use certain types of devices , and anticipated using them would make them feel frustrated or stressed.“I have always loved everything that is technical” (P9), or a ‘non-technological' person. Whenever participants did not own or use a certain technology , they often stated that they did not perceive a need for it. In these cases, they regularly referred to alternative means that could meet their needs, or they stated that their needs or preferences were not in line with what that particular technology had to offer. The participants’ willingness to invest in technological means entailed both the willingness to commit to a personal effort so that a device could be used, as well as the willingness to invest financially. Some participants were very willing to invest, while others pointed out that they only had a limited amount of energy and money, or were not motivated to try or learn a device: “Frankly, I do not feel like putting in the effort” (P29).With regards to technology related attitudes, three types of attitudes could be discerned: the participants’ interest in technological means, the participants’ perceived need for technological means, and the participants’ willingness to invest in technological means. Concerning participants’ interest in technological means, participants often spoke in general terms as if they were a technology-minded person: “When I got my first stroke, my children told me: mother you have to get a mobile phone! That’s when my daughter gave me one” (P6). Members of the social network also influenced participants because they were (co)users of technology. For example, participants saw the ways in which others used modern technology such as tablet computers and electric bicycles. Additionally, participants’ use of communication devices was induced and maintained by relatives, who frequently e-mailed, texted or called participants.The social network included the participants’ partners, their children, other relatives, and peers. These members of the social network provided participants with advice, and gave practical, financial and/or emotional support. Sometimes, participants mentioned that it was because of the social network that they owned a technological mean, not because they saw a need themselves Although less frequently mentioned, participants were also influenced by the actions of organizations; technology suppliers and stores, home care providers, and agencies that can provide financial compensation . For example, participants frequently recollected that a special offer by a store triggered them to buy a device, and pointed out how important technical support was to them. Some participants were concerned whether they would continue to be reimbursed for assistive devices that they had become accustomed to use . Certain policies of home care organizations also influenced the use of assistive technology, but not other types of technology. For example, some participants received information regarding available assistive devices, and were given the opportunity to try out a number of devices.The last component of the status quo was the physical environment. Participants did not like devices that they considered too intrusive . Additionally, physical circumstances outside of the home such as inaccessible buildings and bad weather conditions sometimes interfered with using mobility aids and means of transport.t1. Over the course of the study (at t2 and t3), participants on average acquired a total of 3 devices. A total of 93 devices were acquired, of which 60 acquirements (65%) were discussed in semi-structured interviews with participants. Analysis showed that each time an acquirement had occurred, there were decisive developments that had taken place, which in turn triggered acquirement-enabling mechanisms. A total of 16 distinct developments within various components of the status quo could be identified . In other cases, multiple decisive developments took place, within multiple components of the status quo. For example, a male participant who had recently become single stated he wanted to have more contact with women . Additionally, he observed how people in his social network used their smartphones to chat and exchange photos with others: “When I see others, I see how easy and enjoyable it is to do that” (P24) . These two developments ultimately led him to acquiring a smartphone.In some acquirements, there was just one decisive development that took place. For example, the breaking down of a routinely used technological mean: In some cases, participants acquired various devices because of various decisive developments. For example, a female participant’s decision to buy a new car (to meet her need of staying mobile), was induced by increased maintenance costs of her old car, and an attractive offer made by her car dealer. The same participant also bought a new laptop. In this case, her decision was induced by her grandchildren who wanted to be able to use Skype, and an increased need to experience new things in life.In other cases, multiple acquirements were induced by a single decisive development, or a single combination of decisive developments. For example, a participant renovated his home, which led him and his wife to acquire several kitchen appliances. Other participants experienced a decrease in their health status, which led to the acquirement of multiple assistive devices.When one or more of the aforementioned decisive developments occurred in the life of a participant, one or more acquirement enabling mechanisms were triggered. These acquirement-enabling mechanisms included motivations to acquire, and resources to acquire Table .Table 4M“At night, there are no buses, and on Sundays either, that means I am stuck here” (P17). Second, participants could be motivated because decisive developments had triggered them into wanting to acquire a certain technology. This type of motivation was activated when a participant became attracted to a technology product because he or she had positive expectations of using it and/or because of attractive pricing of the product: “It was marked down, a special offer. I said: ‘This is worthwhile’”(P33). The third type of motivation entailed participants envisioning themselves as future users of a technological mean. This implicated that the participant saw him or herself as eligible to be a user of a technology, and thus part of its group of users. This also meant that the older adult no longer considered him or herself superior to typical users (‘only old and frail people use that’), or inferior to typical users (‘that is something for people who are younger and smarter than me’).Three types of acquirement enabling motivations could be discerned. First, participants could be motivated to acquire because decisive developments led them to realizing they had a personal problem that needed a solution. For example, a participant mentioned he realized he needed a mobility solution: “I have had to learn: save money first, then shop” (P20). Overall, participants appeared selective when it came to investing effort or energy in activities, including purchasing technology.Looking at the resources needed to acquire devices, two types of resources were necessary: an investment of effort to acquire, and an investment of money to acquire. In many cases, the participants themselves, either with or without their partners, put in effort and money. However, participants had a limited amount of both of these resources at their disposal: “I never would have bought it myself” (P6). In a minority of the cases, participants themselves set the external provision of resources in motion. For example, a participant mentioned to her daughter that she was interested in having a smartphone. Subsequently, her daughter selected and ordered a smartphone for her online, without further consulting the participant.In other cases, the resources to acquire were provided by external sources, predominantly relatives or care organizations. This implicated that, in these cases, participants themselves did not have to invest effort or money in acquiring a technological mean. Typically, when resources were provided externally, no motivations to acquire were triggered in the older adult. For example, a participant was provided with an assistive device by a health care organization without ever considering it before: In other instances, the provision of resources was mixed, meaning that effort and money were put in by internal and external sources combined. In these cases, there was a dialogue and/or cooperation between the participant and external sources, and/or an implicit or explicit division of tasks. For example, a participant and her daughter first discussed how and why the participant used her mobile phone infrequently, and subsequently went out and bought a senior phone together. In this case, the participant invested effort and money, and the participant’s daughter invested effort. Cases where an acquirement was partly reimbursed by for example a municipality are also considered to fall under the category of mixed provision of resources.Over the course of the study, the combination of the status quo, decisive developments within the status quo, and enabling mechanisms influenced various types of acquirements Table .Table 5TOut of the 93 technological means that were acquired by participants, nearly 40% were substitutions, meaning a device was replaced by an identical device. In nearly 29% of the cases, acquirements entailed the addition of a technological mean of a familiar type . The addition of a novel, unfamiliar type of technological mean , was less frequent (16%). This also applied to cases in which a technological mean was replaced by a more advanced or newer variant . These types of acquirements were labeled upgrades, and made up 15% of the acquirements.The prevalence of these types of acquirements differed between participants Table .Table 6PFour out of the 33 participants did not acquire any technological means during the study. Of the participants that did acquire technological means, three of them only acquired one device, all substitutions. Seven participants acquired one or two devices (upgrades and/or familiar additions), and seven other participants acquired three to five devices (a mix of three or four types of acquirement). Furthermore, two participants acquired seven to nine devices over the course of the study (either substitutions or familiar additions).t1 – t2), or between the second and third home visit (t2 – t3). Five of these participants acquired two devices, and five acquired four to six devices.In addition, there were ten participants who only acquired technological means in a single time period, either between the first and second home visit . Additionally, some participants were more willing to try out new things than others. For example, a participant who just bought herself an iPhone: “An open-minded person. I want to participate in society. I do not have to be at the forefront... but I want to experience it” (P14). Lastly, participants differed with regards to how willing they were to ask people in their social network for help in buying technological means. This could lead to the postponement of purchases.First, there were personal dispositions that came into play. Some participants were more impulsive than others. This was reflected in the time it took them to make purchase decisions. Furthermore, participants buying few technologies referred to themselves as being economicalOne thing led to another. Beforehand I was not thinking ‘let’s spend some money’” (P14). This occurred for example when participants were renovating their home, and entered a period of spending. In the case of a buying spree, participants typically mentioned that there was a salesperson who understood their preferences and needs.Second, there were situational conditions that influenced the number and types of acquirements by participants. Looking at the role of technology suppliers and stores, participants were more likely to purchase technological means themselves when there was a familiar store nearby that they could go to themselves. Offering home delivery was also mentioned as being important by participants. In some cases, participants found themselves in a buying spree: ““Well, we went to one store. My son told me ‘Mother, you should know that I do not have the time to visit all the stores with you’” (P6). Furthermore, the participants’ health status could limit the amount of energy they had to engage in acquirements, and it could make other situational conditions more critical .There were also conditions which limited or hindered the acquirement of technological means. For example, some participants mentioned they were swamped with choices, once they had decided that they wanted a certain type of device. In these cases, they did not know which model or brand to buy. When this occurred, several participants reverted to buying the same model as people in their social network. Too many options to choose from was also an important reason why participants did not buy devices online. In addition, the social network could limit or delay acquirements. For example, some participants disagreed with their partner on buying devices. Additionally, a participant reported that her children’s assistance had its limits: After participants acquired technological means, they had various experiences while using them, and new technological means could have various implications for their lives . For example, some participants were satisfied with their new device and used it routinely to satisfy their needs, while others hardly used a new device and did not express being happy with it.Analysis showed that favorable and unfavorable consequences of an acquirement  were strongly linked to how that acquirement had originated . This can be illustrated by scenarios that involve both the origins and consequences of acquirements. A total of 36 distinct scenarios could be derived from the interviews. Scenarios included the specific status quo prior to acquirement, decisive developments within that status quo, triggered motivations and resources to acquire, the type of acquirement that occurred, experiences in using the newly acquired technological mean, and implications for the status quo. Moderating factors  were not included in these scenarios.Table As can be seen in Table In the event of a typical upgrade (row #2), a participant originally used a technological mean routinely, but at the same time was surrounded by people who used a more advanced variant of that mean. In favorable upgrade scenarios, participants ended up with using a more advanced variant of a technological mean that met their needs. In a number of cases, this also resulted in participants gradually or suddenly ceasing to use the previous (older generation) technological mean.Looking at the addition of a familiar type of device (row #3), this typically originated from a status quo in which one or more technological means of a similar type were already used to meet challenges. When an older adult added a familiar device, he or she had an additional technological mean at his or her disposal that could help meet challenges.“I am amazed, you know that? That I have learned how to operate it so quickly, and that I have grown accustomed to it. That I am doing it. I would like to see other nearly 79 year olds do this! Who would have thought?!” (P30).In contrast to a familiar addition, a novel addition (#row 4) typically originated from situations in which a challenge was not met by a technological  mean. This mostly occurred when health or safety challenges were not met. In favorable novel addition scenarios, acquirement led to the fulfilling of previously unmet needs. As an added benefit, participants had a positive experience with a new type of device. As such, their internal technology schemas were more profoundly affected, in comparison to the other less novel types of acquirements. For example, a female participant who acquired her first ICT-device, a tablet computer: While 45 out of the 60 acquirements (75%) were successful in the sense that there were favorable consequences as mentioned above, there were also 15 acquirements (25%) that had unfavorable consequences. As can be seen in four typical unfavorable scenarios in Table In all other scenarios, analysis showed that unfavorable consequences of acquirements were predominantly related to the mechanisms that came into play . Two types of situations increased the chances of unfavorable consequences: (1) ‘externally driven acquirements’ with external or mixed provision of resources, and no or limited triggered motivations to acquire on the part of the older adult, and (2) ‘purely desire-driven acquirements’ with internal provision of resources, and personally wanting to acquire as the only motivation to acquire.Examples of externally driven acquirements are provided in Table Yes, yes, I feel really guilty, for not having used the thing” (P15). Some participants reported that they would think twice, the next time they would feel tempted to buy something.Looking at desire-driven acquirements ; these were acquirements in which participants themselves bought a device, solely because their personal want to acquire was triggered, usually by an attractive offer made by a store. In these cases, acquirements were not the result of an unfavorable status quo, or problems that arose as decisive developments. Participants bought a device because they wanted to, not because they really needed to. In these cases, participants felt ‘fooled into it’, and could feel guilty, such as a female participant who bought a laptop: “The current study sought to provide insight in the origins  and consequences  of technology acquirement by independent-living seniors, by applying a realist approach , 52. OurBecause of our focus on understanding seniors’ technology acquirement in a natural setting, our study is inherently interdisciplinary . ConsequFirst, our results indicate that independent-living seniors’ lives should not be considered static. Rather, independent-living seniors’ lives can be characterized as a changeable system of related components . An important characteristic of the status quo is the balance between seniors’ experienced and/or expected challenges related to independent living, and the technological and non-technological means that they have at their disposal to meet these challenges. As such, our findings are in line with gerontological research on seniors’ perspectives on how to age healthy at home , and theSecond, our findings show that technology acquirements by independent-living seniors are the result of change(s). One or more decisive developments are vital for acquirement to occur, and these developments activate motivations and resources for acquirement. These findings are in contrast with existing technology acceptance models –68, thatan idea, practice or object that is perceived as new by an individual” [If the product can meet an otherwise unmet need, the elderly consumer may be able to overcome the risk of buying an unknown good” [Third, it is worthwhile to compare our findings to classical process models that describe stages of technology adoption  and consividual” . In the ividual” –87. Overividual” , 88. Addividual” , 89. Thiividual” , 89. In ividual” , 89. Thewn good” .Fourth and last, it seems that the motto ‘the customer is always right’ very much applies to older adults. In line with previous research , the vasWith regards to our data collection and our interactions with participants, several limitations need to be discussed. First, our decision to only interview participants on devices that could support activities of daily living, personal health or safety, mobility, communication, and physical activity may have induced a bias. It is important to note that older adults have more needs than those described in the current study, such as the need to be creative, and the need for personal development. Additionally, older adults also buy nonessential goods such as leisure, entertainment, personal care, and luxury goods .Second, our interview data may have been affected by recall bias since we asked our participants to look back in time in order to construct their acquirements of technology. More specifically, research suggests that older adults’ memory for information tends to skew more positive than that of younger adults , causingThird, as the study progressed we noticed that participants increasingly considered us trustworthy and opened up more, which facilitated our data collection. On one occasion, a participant disclosed that her acquirement of technology was influenced by an interview. She noted that the interview had caused her to reflect on her technology use, and that this was one of the reasons for her to acquire a number of technologies. According to her, this was due to the topics we addressed, and not a consequence of our style of interviewing. We subsequently asked all other participants whether they felt we were influencing their acquirement and use of technology. All other participants responded that this was not the case.Looking at our model and findings, there are several areas that could benefit from further research. First, our design focused on exploring why independent-living seniors acquired devices, and not on why they did not. Further research is necessary to understand the context and mechanisms of acquirement processes that are not started, or are aborted. This type of research may also lead to insights on mechanisms that impede acquirement, and mechanisms that limit the enabling mechanisms that we have described.Second, the current study solely describes older adults’ perceptions of their status quo and developments and mechanisms that led to acquirement. Our model could be expanded by also integrating the perspectives of older adults’ spouses and relatives, as well as care organizations they interact with. It would be interesting to integrate their perspectives on the older adults’ status quo, their views on what mechanisms influence acquirement, and their motivations for providing resources for acquirement. This also would entail collecting more information on the size and nature of older adults’ social networks. As others have pointed out, successful aging in place is socially and collaboratively accomplished , 94.Third, our model could benefit from better specifying the role of affect in technology acquirement processes. While emotions were part of the stories told by participants, we feel that using qualitative methods may not be the best way to capture their precise role. Quantitative research, for example by employing scales developed by Bagozzi , may sheFinally, our participants’ views and contexts, as well as their acquirements of technology are likely to be influenced by cultural aspects and the organization of the local and national health care system. Studies in other regions and countries are necessary to determine if our results can be generalized.Independent-living seniors are not only different from each other; they are also different from themselves at different times. This poses problems for those that seek to deploy or implement technologies that aim to support aging in place. It is challenging to present independent-living older adults with relevant and timely offerings.In dealing with the aforementioned issues, the C-TAILS model can be used to facilitate the deployment and allocation of already existing technological solutions for aging in place. In this pursuit, the C-TAILS model can be used for assessing an older individual’s specific status quo, to understand his or her specific needs and circumstances, in order to determine if technologies in line with these needs would be a welcome addition. Ideally, organizations would over time learn what decisive developments and personal motivations influence their independent-living clients’ technology readiness, and organize the allocation of technological solutions to clients accordingly. Using this strategy, the number of ineffective ‘externally driven’ technology acquirements can be reduced, and older adults can be provided with meaningful and welcome technological means to help them age in place.A demand results from the interaction of a person with his or her environment, a segmentation perspective that includes both the person and the situation is needed to explain demand” [Additionally, the C-TAILS model can be of benefit to practice by informing more effective forms of market segmentation, market-research and product design that are more in line with independent-living seniors’ needs and perceptions. Looking at market segmentation, others have noted that dividing a heterogeneous population such as independent-living seniors in subgroups is problematic, even more so if traditional dimensions such as demographics and personal characteristics are used and treated as being static , 96–99.  demand” . Likewis demand” .Technology acquirement by independent-living seniors may be best characterized as a heterogeneous process with many different origins, pathways and consequences. Furthermore, technologies that are acquired in ways that are not congruent with seniors’ personal needs and circumstances run a higher risk of proving to be ineffective or inappropriate. Yet, these needs and circumstances are subject to change, and the C-TAILS model can be employed to better understand contexts and mechanisms that come into play.


Animals that live together in groups often face difficult choices, such as which food resource to exploit, or which direction to flee in response to a predator. When there are costs associated with deadlock or group fragmentation, it is essential that the group achieves a consensus decision. Here, we study consensus formation in emigrating ant colonies faced with a binary choice between two identical nest-sites. By individually tagging each ant with a unique radio-frequency identification microchip, and then recording all ant-to-ant ‘tandem runs’—stereotyped physical interactions that communicate information about potential nest-sites—we assembled the networks that trace the spread of consensus throughout the colony. Through repeated emigrations, we show that both the order in which these networks are assembled and the position of each individual within them are consistent from emigration to emigration. We demonstrate that the formation of the consensus is delegated to an influential but exclusive minority of highly active individuals—an ‘oligarchy’—which is further divided into two subgroups, each specialized upon a different tandem running role. Finally, we show that communication primarily occurs between subgroups not within them, and further, that such between-group communication is more efficient than within-group communication. When individuals live together in groups this challenge becomes even more demanding as, if they are to avoid group fragmentation, they must ensure that they effectively coordinate their individual actions to a single purpose.Temnothorax [Temnothorax ants a key stage in colony emigration—disseminating information about potential nest-sites—is organized via stereotyped physical interactions in which a knowledgeable individual physically leads a naive nestmate back to a new nest site, in what is called a tandem run [Although group living is associated with a range of benefits, the shared occupation of a communal nesting site is also likely to induce costs associated with nest degradation, colony growth and parasitism. Consequently, group-living species often perform an emigration in which the entire society relocates to a new nest site . The mecnothorax –4 and innothorax ,6. In condem run –10. SuchTemnothorax albipennis ants were repeatedly challenged with a difficult consensus-formation task—selecting between two identical nest sites. In order to trace the propagation of information about the available nest sites within the ant population, each ant was tagged with a unique radio-frequency identification (RFID) microchip and the identities of both individuals participating in each tandem run were recorded. By representing each tandem run as a directed link from the leader to the follower, we are able to reconstruct the network of social interactions underpinning the group decision.In this paper, we present a series of experiments in which colonies of The results are divided into three parts. In the first, we show that tandem running activity is concentrated within a minority with a consistent membership. The second section describes the basic topological features of the tandem recruitment networks formed by the minority that participates in tandem running. Finally, we examine how the role specializations of the leader and follower within each tandem pair, interact to determine the quality of the tandem run.2.(a)Temnothorax albipennis ants were collected in September 2011 from the Dorset coast, UK. Colony population sizes ranged between 72 and 113 workers , and all colonies possessed brood of all stages. Prior to the experiments, all ants were individually tagged with RFID micro transponders , according to established protocols [2), ants that removed their tags after the fourth tagging attempt were permanently removed from the colony  of ants per colony).Six colonies of 2). Temnothorax ants behave as though such nests are of poor quality [The colonies were initially housed in small nests (25 × 30 × 1 mm), with a single entrance , and a transparent acetate roof allowing light into the interior nest cavity, fitted with a regular grid of holes , and the three nests arranged into an equilateral-triangle, with the two luxury nests—we term them ‘left’ and ‘right’—placed on either side of the original . During each emigration, a handheld RFID reader was used to record the identity of the nest from which each tandem departed, the associated tandem start and end times, and the identities of both participants. A high-resolution video camera placed above the arena was used to record the emigration and to determine whether each tandem run reached its target nest, or whether it broke up while en route.At the end of each emigration the colony was removed from the arena and re-emigrated into their initial low-quality nest. The above emigration procedure was repeated five times for each colony. To minimize the effects of learning , 7 days (b)d, and the final distance from the end point of the tandem to the goal, d′, that is d − d′ . To arrive at a tandem quality metric that varies in the range 0–1, this difference was then normalized by the initial distance to the target, that is, Q = (d − d′)/d [Q = 1, and unsuccessful tandems Q < 1.Tandem runs sometimes break up before reaching their destination. Nevertheless, partial tandem runs still convey information ,15. Ther − d′)/d . Hence s(c)Q. Accordingly, the number of tandem runs that an ant led and followed respectively define its in- and out-degree centrality, whereas the sum of qualities of the tandem runs it led and followed define its weighted in- and out-degree centrality.The sequence of tandem runs that occurred during an emigration was represented as a static network in which individual ants were represented as nodes, and tandem runs were represented as directed links pointing from the tandem leader to the follower. Links were also weighted according to the tandem quality 3.(a)n = 30 emigrations) of the colony participating. This value is in close agreement with a previous estimate of 35 ± 8% (n = 12) for T. albipennis [n = 6) for T. curvispinosus [n = 30) of the colony engaging in following, and only 12.1 ± 0.8% (n = 30) engaging in leading.Participation in tandem running showed a clear division of labour, with a mean of only 29 ± 1.6% . Comparisons between the original and the synthetic participation records revealed that the observed activity records had significantly more ants common from one emigration to another than the permuted versions (c). Hence, the emigration organizers are a stable minority with a core membership that reliably re-assembles across multiple emigrations, that is, an ‘oligarchy’ [In order to assess the stability of the emigration organizers in ra ants,  performeversions c. Hence,igarchy’ .Figure (b)a; linear mixed-effects model, response; out-degree, predictor; participation latency, random effects; emigration, colony identity and ant identity; effect of latency, β = − 0.0078 ± 0.001, p < 0.00001, in degree; β =−0.0026 ± 0.0006, p < 0.0001). Similarly, participation latency also predicted the weighted out- and in-degree, that is, the summed quality of tandems led and followed . Hence, the ‘first responders’ came to occupy significantly more central positions in the tandem recruitment networks than those that took longer to participate.Representing the sequence of tandem runs as a time-aggregated network revealed the presence of ‘hub’ nodes with high centrality . As tandfigure 3b; LMM, response; log10(Q), effect of number of tandems leader led; β = 0.013 ± 0.0035, p = 0.00023), but no dependence upon the number of times the follower had so far followed . This shows that tandem run quality is primarily determined by the amount of practice that the leader has in the leading role, but not the practice of the follower in the following role.As ants that engaged in several tandem runs had the opportunity to improve their leading or following skills, we next explored the association between tandem run quality and practice. Accordingly, we tested whether the quality of a tandem run depended upon the number of times the leading ant had led so far in that emigration, and the number of times that the follower had followed. Tandem run quality showed a significant positive dependence with the number of times the leading ant had so far led . Hence, we conclude that at least within single emigrations ants specialized upon a single role. Indeed, this specialization is confirmed by the conspicuous ‘hub-and-spokes’ motifs visible in most of the networks  no dependence between the average number of tandems each ant leads and the number it follows, or (ii) a positive dependence, arising from variation in activity levels. In fact, node in- and out-degree displayed a strong negative dependence . Identical patterns were observed when node centrality was defined by the weight of the incident edges, that is, by the summed quality of the tandem runs each ant led or followed . Hence, the neighbours of ants that were particularly active tandem leaders tended to be particularly inactive leaders, whereas the neighbours of particularly active followers tended to be particularly inactive followers.Since correlations between node in- and out-degrees do not provide information about the overall connectivity of the network, we next tested for associations between the centrality of each node, and the centrality of its neighbours. Given the key role of the participation latency in determining an ants' centrality, and given that the first-responders' first few generations of followers would also have ample time to accumulate a large number of tandem runs, we expected that central nodes should neighbour other central nodes. In other words, the networks should display positive degree assortativity. However, in contrast to our expectations the tandem recruitment networks displayed strong negative assortativity for node out-degree, and a weaker negative assortativity for in-degree .As well as varying in terms of their centrality, ants also varied in the extent to which they were biased towards the left or right nest site, as indicated by the number of tandems they led or followed to either site. To assess the extent to which similarly biased individuals were clustered in the recruitment networks, we quantified bias by counting the number of tandem runs to each nest that each ant had been engaged in. Hence, an ant that participated in more tandems to the left than to the right nest was classified as left biased (ants that engaged in the same number of tandems to both nests were classified as unbiased). For each node, we then measured the proportion of its nearest neighbours that shared its nest bias, and repeated this procedure for the second, third and e levels e.Taken together, these results show that the first responders act as ‘nuclei’ around which the network is assembled. These first responders eventually become network hubs, and although they interact relatively little with one another, they nevertheless each accumulate a relatively large number of followers that together constitute a local ‘domain’ of nestmates that share the same nest commitment.(c)t) predicts its behaviour in a later emigration (at t + lag). As each colony underwent five emigrations each separated by 7 days, the pairwise correlations were measured at four different time-lags . Given that division of labour and individual behavioural specialization are universal hallmarks of social organization within colonies of social insects [Temnothorax ants are relatively slow to mature, we predicted that individuals would exhibit strong behavioural persistence across multiple emigrations.Models of nest-site selection in social insects have successfully simulated the formation of a consensus group decision by assuming that all colony members are essentially equivalent, and that all follow the same set of rules of thumb ,18,21–24 insects –28, and a). Somewhat surprisingly, in-degree correlations centred around 0 for all lags, and the statistical significance of these correlations only just exceeded chance levels for the shortest time lag . However, the out-degree correlations exhibited a clear positive bias for all time-lags (c). Therefore, both the order in which the recruitment network is assembled, and the ‘hubness’ of each ant within the network, are preserved from across multiple emigrations. The presence of individual consistency in the number of tandems led and followed further confirms that the negative correlation between the number of tandem runs led and followed within single emigrations (c) is not an artefact of constraints imposed by the finite time required to perform a tandem run.Overall, the correlations were more noisy than predicted. Nevertheless, the participation latency exhibited above-chance correlations—notably so for the longest time lag 32 days; a. Somewh 8 days; b. Howeveime-lags c. Therefgrations c is not (d)Rleading, Rfollowing) was defined as the number of emigrations in which an individual led or followed at least one tandem run. Because leading and following reliability are defined in binary terms (e.g. leading or not leading), reliability reflects the extent to which a given individual can be depended upon to perform a particular task when the opportunity presents itself.In this section, we investigate an additional component of individual behavioural consistency: task reliability, which is the likelihood that an individual performs a given task when it is given an occasion to do so. The reliability for tandem leading and following  (a). Other than individuals that led and followed in every emigration (of which there were none), the rarest category of tandem participant was that of the consistent ‘core’ oligarchy members, that is, ants that always either led or followed , ants that always followed but never led , and ants that always led but never followed . These reliable leaders and followers were also highly effective within their specialized role. Thus, within any given emigration, the most reliable leaders led more tandems than any other category of ant (b), and these tandems were of higher quality than tandems led by less reliable leaders , whereas the most reliable followers followed more tandems than any other category (c), and these tandems were of higher quality than those in which unreliable individuals followed. However, the negative association between following reliability and the quality of tandems led  a. Other y of ant b, and thcategory c, and thleading reliability of leader and follower, ΔRleading = Rleaderleading − Rfollowerleading, which was positive if the leader of the tandem was a more reliable leader than the follower of tandem; and (ii), the signed difference between the following reliability of leader and follower, ΔRfollowing = Rfollowerfollowing − Rleaderfollowing, which was positive if the follower was a more reliable follower than the leader. Accordingly, each tandem run was classified according these two differences , and the counts of the ants in each category were plotted as a joint distribution, ftandObs. Most tandem runs exhibited positive ΔRleading and positive ΔRfollowing values (d). In other words, most tandem runs were composed of a leader that was a more reliable leader than the follower, and a follower that was a more reliable follower than the leader, which is consistent with the presence of assortative matching.As the performance of tandem pair was acutely sensitive to how individuals with different levels of specialization in each role allocated themselves to leading or following duties, we next explored whether ants preferentially assorted with one another within tandem pairs according to their reliability in either role. To test for the presence of such assortative matching, we first characterized each tandem run by measuring the differences between the role reliabilities of leader and follower. Thus, for each tandem run we obtained: (i) the signed difference between the g values d. In othRleading and ΔRfollowing was a real phenomenon, we compared the observed distribution of leader–follower role reliability differences, with that expected in the absence of such matching . These comparisons revealed that the observed distribution exhibited significant bias towards the upper-right quadrant, in which leaders are reliable leaders, and followers reliable followers . Therefore, pairs of tandem running ants are not randomly assembled, but rather their composition is consistent with a division of labour between leading and following specialists.To assess whether this bias towards positive values of Δ4.Decisions made by animal groups may be placed on a continuum, extending from democratic (majority decisions) through oligarchic (minority decisions) to despotic (leader decisions) ,29. We hOur investigations into the topology of the tandem recruitment networks revealed several properties in common with networks generated by the well-known ‘preferential attachment’ model of network growth. In these models, networks are built by sequential addition of new nodes, which are more likely to be connected to the most well-connected of the existing nodes, thus creating a self-reinforcing process in which the ‘rich get richer’ . Like thThe assortative matching between experience and role that we have described in tandem running ants bears a striking resemblance to that seen in foraging stickleback fish in which the joint foraging efficiency of foraging pairs is dependent upon the difference in temperament between the leader and follower . ManipulInterestingly, the presence of an association between specialization and efficiency during tandem running is in contrast to the absence of such an association for foraging, brood transport and nest material collection in a closely related ant . We suggFormica sanguinea, Camponotus sericeus and Diacamma indicum, only a small minority of the workers perform the majority of the recruitment, and the removal of these recruitment specialists severely inhibits the emigration process [These considerations aside, the delegation of the fate of the group to an ‘oligarchy’ probably carries a degree of risk. For example, if the oligarchy members are in some sense special, then the group could be vulnerable to the loss of only one or two oligarchy members. Indeed, in the ants  process ,39. Give process , there i process . Consequ


Here we introduce a toy model of patterning in one spatial dimension, which can be seen as an extension of Wolpert’s paradigmatic “French Flag” model, to patterning by several interacting, spatially coupled genes subject to intrinsic and extrinsic noise. Our model, a variant of an Ising spin system, allows us to systematically explore expression patterns that optimally encode positional information. We find that optimal patterning systems use positional cues, as in the French Flag model, together with gene-gene interactions to generate combinatorial codes for position which we call “Counter” patterns. Counter patterns can also be stabilized against noise and variations in system size or morphogen dosage by longer-range spatial interactions of the type invoked in the Turing model. The simple setup proposed here qualitatively captures many of the experimentally observed properties of biological patterning systems and allows them to be studied in a single, theoretically consistent framework.A crucial step in the early development of multicellular organisms involves the establishment of spatial patterns of gene expression which later direct proliferating cells to take on different cell fates. These patterns enable the cells to infer their global position within a tissue or an organism by reading out local gene expression levels. The patterning system is thus said to encode  Here we are interested in essential conditions for pattern-forming systems to support rich and robust positional specification of cells. Rather than focusing on any particular organism, we analyze a minimal tractable model that can qualitatively reproduce pattering features across a diverse range of biological examples. In the process, we illustrate and formalize a number of concepts pertaining to developmental pattern formation.Shape and size are global properties of organisms and of their constituent parts. Yet organisms develop and grow by processes that are intrinsically local: cell division, fate commitment and differentiation, migration, and death. To coordinate these processes appropriately, cells must reproducibly activate different gene expression programs in a manner that is positionally specified, or One possibility for cells to acquire their position-dependent fates is to establish a field of developmental cues that the cells can “read out” to learn about their individual locations in an organism and hence to appropriately coordinate their behaviors. Often, these cues are gradients of patterning molecules, called morphogens. A morphogen gradient is a chemical “coordinate system” in which the organism’s body plan is drawn ; in thisPatterning strategies need not rely on the existence of signals distributed throughout the organism. Organism or tissue boundaries are intrinsically different from the bulk, and one can envision local biophysical mechanisms that propagate information from the boundary into the bulk to set up a global pattern. The Turing model is an example of this kind, where local rules are expressed as a set of reaction-diffusion equations and the steady-state pattern is determined by the boundary and initial conditions . A TurinChanging focus from systems continuous in space, time, and concentration to discrete setups, one can think of cellular-automata-like models that, starting with a defined initial state at the boundary of a finite domain, propagate that state into the bulk, creating a discrete pattern in a lattice of cells. Similarity to such a local, rule-based mechanism can be found, for instance, in developmental notch signaling , 11.Dictyostelium cells  = 1. Such a pattern is said to convey “one bit” of positional information, an amount sufficient to reliably separate the anterior from the posterior, or odd from even rows of cells; generally, one bit corresponds to the amount gained by an unambiguous answer to an optimally posed yes/no question. In the case of multiple patterning genes, a combination of gene expression states, e.g., {ON, OFF, ON, ON} or {+1, −1, +1, +1}, can be seen as a “codeword” for some particular position. The capacity of this code, independently of how the gene expression patterns are set up or read out, is again given by the first term in 4 = 16 distinct gene expression combinations is used equally often across all locations x in the tissue.Considering a single patterning gene without noise, gene expression achieves maximum positional information by partitioning all S[Px(x)] = log2N for cells that are uniformly distributed over coordinate x, as we assume in our model. This way of writing positional information emphasizes that log2(N) bits is the upper bound on the positional information in a patterning system, which would correspond to an unambiguous identification of every location x based on the expression pattern σ. Positional information is decreased from this bound by the second term in Mutual information is symmetric in its arguments, so that we can rewrite x, given the expression levels σ. It can be shown that the expected error of any estimator Px(x) as the prior distribution of an estimator at position x. The best choice for an estimator of position is the expectation value Px(x). For the uniform Px(x), the variance of x can be expressed by the entropy S[Px(x)]:σ can only decrease the entropy (S[Px(x)] ≥ 〈S[P(x|σ)]〉σ). We assume that P(x|σ) = P(σ|x)Px(x)/P(σ) is the Bayesian inversion of the correct expression state of the system P(σ|x). From S[P(x|σ)]〉σ = log2(N) − I, so that we can finally writeI → log2N bits. This relationship is analogous to the relationship between positional error and positional information for continuous systems , one finds that the term corresponds to a global, all-to-all (long range) negative interaction between any pair of locations in the lattice. Crucially, such a term is an additive addition to an optimized Counter network: because the optimized Counter exhibits the ON / OFF balance already, the new term doesn’t change the Counter state itself, but only makes states deviating from it less likely. Realistically, the strength and range of such interaction cannot be made infinite; the relevant question is therefore whether canalization and scaling can be obtained with a Before proceeding, we give an intuitive account as to why negative long range spatial interactions can be of benefit. A particular property of Counter patterns is their balanced use of m(x) which spans its dynamic range over a default system size of N = 60 lattice sites. We model variations of the system size without scaling of the gradient by cutting the system and the gradient short by 10 lattice sites or extending it by 10 lattice sites at constant value of the morphogen signal in the posterior . Such perturbations can be interpreted as variations in the morphogen dosage, and robustness to such perturbations has been a focus of several experimental studies. ϵ, while in the absence of such interactions the patterns experience large shifts with ϵ.Next, we examine the robustness to systematic perturbations in the morphogen signal in detail. We introduce an additive offset ϵ, and the long range interaction magnitude, To quantify the stability of the pattern, we compute the overlap, In sum, we have shown that “canalization” and “scaling” in our toy model system can be provided by the addition of long range negative spatial interactions. Curiously, these interactions can be added to a previously optimized Counter network without any need to change the optimized parameters, because they do not affect the energy or the identity of the Counter pattern ground state. As in the Turing model, these interactions stabilize the ground state. Unlike the Turing model, however, the Counter pattern itself is generated solely by a joint action of a French Flag-like morphogen signal readout and local gene-gene interactions.ϵ could be measured directly as a low value of information ϵ would not affect the expression patterns. The question is whether to gain robustness one needs to explicitly maximize PI while jointly minimizing ϵ shifts in the morphogen signal considered above).Should the long-range negative interactions that confer robustness also follow from an information optimization principle? Recalling our introductory remarks, robustness to, e.g., morphogen dosage We introduced a tractable toy model of patterning that extends Wolpert’s French Flag model, in which several two-state genes respond to a morphogen signal based on a fixed set of thresholds. Our extension allows these genes to cross-regulate each other, to interact spatially , and to include the effects of both intrinsic noise  and extrinsic noise . A physics equivalent of our model is a set of coupled 1D Ising chains responding to inhomogeneous external field and this link to statistical physics allows us to perform most of our computations exactly. In this well-defined setup we ask which patterns of gene expression encode the maximal amount of positional information; our enquiry is set in an optimization framework, where for each choice of noise magnitude and morphogen signal profile we look for the optimal pattern of gene-gene and spatial interactions, and examine the resulting spatial patterns of gene expression.K binary patterns that can be realized by K genes appears equally often along the spatial coordinate; this combinatorial code for position is, on information-theoretic grounds, the best achievable solution, independently of the patterning model. The Counter pattern can be realized if each patterning gene can be activated at a different threshold, and if the local gene-gene interactions can be adjusted; the optimal interactions are predominantly repressive. Increasing the noise quickly perturbs the Counter pattern, until the optimal pattern switches from Counter to French-Flag-like set of stripes, and finally, to a set of redundant genes that are all activated at the same threshold. Addition of short-range positive spatial interactions of intermediate strength makes the optimal patterns substantially more stable against increasing noise; qualitatively, this effect is analogous to noise averaging due to diffusive coupling in continuous systems. Strong short-range negative interactions generate an alternating pattern of gene expression which robustly separates odd from even rows of cells, a strategy that can yield one additional bit of PI when noise is low.We find that with vanishing noise magnitude, the optimal gene expression pattern is the so-called Counter, where each of the 2Qualitatively new effects emerge if the spatial interactions can be long-ranged. We observe that our discrete, Ising-model-based model exhibits Turing-like patterns whose spatial scale is set by the range of the repressive interactions. Surprisingly, we find that the energy function, optimized to yield Counter patterns with high positional information, can be modified by the addition of strong long-range repressive interactions. This modification does not perturb the Counter pattern, but makes it robust to changes in the morphogen dosage and to changes in system size by producing patterns that approximately scale with system size.Taken together, our analysis allows us to identify elements—the basic building blocks—of positional information: adjustable thresholds as in the French Flag model to differentially drive gene activation; local repressive interactions to generate combinatorial codes for position; short-range positive spatial couplings to enable noise averaging and stabilize the patterns; and long-range negative spatial couplings to provide scaling and robustness via canalization. The optimal patterning system thus combines elements from both the French Flag model with the elements inherent to the Turing mechanism. Furthermore, these elements need not be identified and combined by hand, but emerge from a single information-theoretic optimization principle, and their contribution towards encoding of positional information can be individually quantified.Drosophila, intermediate levels of expression are of crucial importance [The explicit purpose of this work has been to provide conceptual clarity and computational tractability rather than a detailed model of any particular patterning system. In order to achieve our goals, we had to sacrifice several crucial aspects of biological realism. First, real patterning does not happen at equilibrium, but is rather a driven dynamical process evolving from some initial state. Second, as the real patterning mechanisms are dynamic and might involve multiple timescales, noise mitigation mechanisms beyond spatial averaging, e.g., temporal averaging, should be available. Third, the assumption that expression states of patterning genes are binary might be poor. For example, in the gap gene system in portance . On the portance . Furtherportance , 16. An Q do not matter so long as the system has the ability to access patterns that achieve high positional information (which can be found by optimization). Pattern-forming processes can be complicated and can include spatial interactions between nearby cells or even long-range or global interactions. Ultimately, however, these systems generate patterns whose power is quantified by a local quantity, the positional information I, which is sufficient to summarize the limits to readout error. For optimal solutions to the patterning problem, this locality of positional code is crucial: there are many possible pattern-forming systems, but only in a restricted subset do we expect high information about global position to be available locally.Despite these approximations, our model qualitatively recapitulates many aspects of the optimal patterning solutions that have been reported previously in more realistic setups, where the required computations are substantially more complicated –40, 50. S1 AppendixA lower bound on the error of a positional estimator with limited positional information is derived.(PDF)Click here for additional data file.S2 AppendixThe effect of noise in the input field on an Ising model is approximated. Furthermore, methods to compute positional information in an Ising model by transfer matrices and Monte Carlo sampling are outlined.(PDF)Click here for additional data file.S3 AppendixThe positional information in a discrete morphogen field with Gaussian noise is computed.(PDF)Click here for additional data file.


A regular work day for intensivists can be emotionally draining, as we witness suffering, fear, pain, tragedies, unfair treatment of children, death…. We may experience the mental stress of dealing with nursing shortages, increasing family demands, and frustration related to interpersonal conflicts  among other issues . For theSeveral studies involving nearly every medical and surgical specialty indicate, however, that approximately one of every three physicians experiences burnout at any given time. Burnout is characterized by behaviors such as losing enthusiasm for work , treating people as if they were objects , and having a sense that work is no longer meaningful  .moral dilemma in which one is uncertain what ethical action to take, MoD is experienced by those who feel constrained from acting on their ethical judgment. Constraints are still recognized frequently as external, institutional ones . This concept emerged in nursing ethics: “a challenge that arises when one has an ethical or moral judgment about care that differs from those who are in charge” . Thus, inal ones . Internanal ones .perceived is very crucial, since we may feel strongly that an action is unethical while a colleague may feel just as strongly the opposite. It is well known that MoD in pediatric intensive care (PICU) can be linked to aggressive treatment, witnessing repeated suffering, futile care, and high levels of chronic disability post discharge and may be aggravated by work environment issues such as power imbalances, improper communication, decision-making conflicts, unrealistic expectations, lack of resources or personnel, and a high index of medical errors Nourish “moral courage”: an ethical health-care professional will always need moral courage, i.e., be prepared to face tough decisions and confront the uncertainties associated with the resolve to do the right thing despite the consequences faced. This need for moral courage is especially true when the perceived constraints are within ourselves or when we face opposition within our own ranks. The courageous person accepts and assumes moral responsibility for the perceived consequences of his or her action; a physician may master fear without necessarily eliminating it (ating it .2)Seek peer support: this type of sharing, with someone that can understand one’s struggles, has a good listening ear and acknowledges and validates what one is experiencing seems essential for survival in the profession (ofession .3)Take time off: having resting periods, time offs, vacation, and long weekend getaways: these are necessary for one’s well-being. Physical activity, exercise, enjoying nature, and managing stress through mindfulness are strategies shown to increase the capacity to take new challenges with stride (h stride .4)Find another passion: having another interest outside work, even one connected with the field, such as volunteering on medical missions, has been very rewarding for me. Having a favorite sport, a pet, or pursuit  have been cited by many PICU colleagues as their way to recharge and continue on the job. Cultivating a spiritual life, within or outside an organized religion, has been found to be important to sustain one’s motivation and engagement. To focus on what really matters in the work I do – the children and their families – certainly helps me keep going.At the personal, individual level, a general mindset that encompasses the following may be helpful:There is much that can be done to make the PICU a more “morally habitable” place. Given the current levels of reported MoD, health administrators need to attend to this important workplace factor and ensure the support necessary for staff to address it. As practitioners, we ought to develop insight into our feelings and reactions, contribute to an open environment where team work is a healthy practice, and adopt a lifestyle that recharges us for the next difficult case.The author confirms being the sole contributor of this work and approved it for publication.The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Pleiotropy, natural selection and the evolution of senescence. Evolution. 1957; 11:398–411.Imagine that in a research field, which flourishes on funds allocated for getting an answer to a pressing question, the answer is eventually found. There will be no need to support the field any further. Specialists who sacrificed their lives to developing it will be uncompetitive in other fields, which are being developed by other scholars. That is, science, unlike practice, needs questions, not answers, which may have value for science only as far as they provoke further questions. In this regard, the value of the commented opinion paper  is unque“We’re being offered incrementally smaller amounts of survival time at a very high cost…” .Questionable is the practice of extracting quotations out of their full contexts. However, how else can one justify comments on it?“Smaller” and “very high” are quantitative categories. Is there a way to estimate them by numbers? One way is suggested by the Preston curve, which shows cross-country relationships between per capita gross national product (GNP) and life expectancy (LE) . Transfo“A clue about what we should do instead…: … attacking aging itself rather than the diseases associated with it…” .μ captures the probability of death per unit time, C is a population-specific parameter, which does not depend on age (t), μ0 captures the mean initial vulnerability to the causes of death, and γ captures the mean rate of the age-dependent increase in vulnerability, i.e., the demographic rate of aging.How can one know that aging itself rather than something else is attacked? In populations, aging is manifested as a gradually increasing risk of death with increasing age. This relationship is captured by the Gompertz–Makeham law (GML):γ may be regarded as targeting “aging itself.” Treating human mortality and survival patterns according to GML suggests that changes in C rather than in γ are responsible for historical advances in human lifespan , how one should esteem testing numerous putative anti-aging drugs for their applicability to humans? Is not it another way of making people pay for the anti-aging agenda?—This time for research  aimed to check whether prospective products are useful, rather than for ready-to-use products having unproved usefulness. Thus, we have another Faustian bargain, albeit more intricate.Ironically, the most praised “anti-aging” drugs, such as resveratrol, rapamycin, and metformin, are believed to mimic the effects of shifting body energy balance from storage, growth, and self-reproduction to self-maintenance , 12. TheThis is not to say that aging research has turned into scholastic exercises performed for their own sake. Delving into the basic mechanisms of aging does help to find novel therapies, which are likely to be overlooked in studies focused on a specific malady. An example is the story of resveratrol, which apparently fails to culminate in a pill to attack human aging, yet continues by patenting new drugs to attack human diseases .The author confirms being the sole contributor of this work and approved it for publication.The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Dear Editor,The field of complex mixture analysis has advanced significantly in the past two decades, although its history goes much further back. When Dirk Willem van Krevelen developed his now eponymous diagram in 1950 to represent the chemical makeup of coals, he proposed that the chemical nature of samples, including the presence of structural motifs and chemical properties, could be inferred from the elemental ratios of the sample.Since 2003, when the modern van Krevelen diagram was first used to visualise complex MS datasets,m/z 200 and 700. Due to its ubiquity and complexity, SRFA was chosen to demonstrate the capability of the visualisation tools described herein.In the field of complex mixture analysis, a number of methods are available to the enterprising chemist; however, Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) reigns supreme as the ‘gold standard’ technique.With the mass accuracy of FTICR MS spectra in parts‐per‐billion,i‐van Krevelen for short, is generated using the Bokeh Python plotting library.i‐van Krevelen scripts are three text files containing (1) monoisotopic peak assignments, (2) isotopologue peak assignments, (3) remaining unassigned, but detected, peaks. Example input files are included with the suite of presented tools. The Bokeh API allows for the straightforward coding, in Python, of complex JavaScript (JSON) plots as HTML5 Canvas objects. The output from this tool is a standard HTML document compatible with any modern web browser such as Google Chrome, Firefox, or Internet Explorer.We have developed a version of the van Krevelen diagram, which introduces interactivity, and allows the analyst, or reviewer, to interrogate the data in an intuitive way. This interactive van Krevelen, or i‐van Krevelen software is the generation of interactive diagrams including a centroid mass spectrum, van Krevelen, DBE vs carbon number plot and the modified Aromaticity Index vs carbon number plot.The main feature of the The benefits of these features will be immediately obvious to any analytical chemist who has tried to make sense of complex static van Krevelen diagrams of complex mixtures.For example, in a standard van Krevelen plot, numerous points may be superimposed if they share elemental ratios but differ in molecular formulae. As a van Krevelen plot is a specific type of scatter plot, it is susceptible to the same problems as other any other scatter plot, and can be misinterpreted when hundreds or thousands of points are plotted. Whilst the addition of colour and transparency can reduce these problems, they are not eliminated entirely.n most abundant ions – an approach utilised in some previous statistical analyses of complex spectraReducing complex data down to a two‐variable van Krevelen plot inevitably represents a loss of information. In our tool, we have therefore created several 2D plots that are linked together. An example of this layout is shown in Fig. On a second tab of the HTML page, the centroid mass spectrum is plotted with the identified isotopomers, as well as the remaining unassigned peaks. An example of this is shown in Fig. Finally, on a third tab, the data table is presented that is required to generate the plots, and it is also interactively linked to the plots, meaning that selections made on any plot are highlighted in the data table, and vice versa. This data table is downloadable as a text file.et al.;i‐van Krevelen software and other included scripts. The included formula generator is especially useful for determining assignment error thresholds, for example by allowing the user to determine the minimum distance between possible compounds at a given m/z, and thus adding confidence to the assignment.The developed code also includes a number of related Python scripts for: (i) automated batch plotting of publication quality van Krevelen and DBE vs Carbon Number plots; (ii) heteroatomic class distribution calculation and plotting; (iii) an “all‐possible‐formula‐generator”, which calculates a list of possible, logical, chemical formulae as based on work done by Kind i‐van Krevelen package based on the SRFA FTICR MS data can also be found online.Overall, these interactive plots, and their combination, represent a step forward in the analysis of complex mixtures by high‐resolution mass spectrometry. The tools are open‐source and available freely through GitHub with a GNU General Public License v3.0, encouraging others to experiment with and build upon them. The GitHub repositoryFuture work could incorporate the Datashader


During submission, the authors stated that they hadreceived appropriate patient consent, however, the author group has notified the journalthat they have failed to receive the patient's approval.In the artice, “High Dose of Nimustine as an Adding on Treatment for Small-Cell LungCancer with Intracranial Metastasis: a Case Report and LiteratureReview”,