In STEM education and careers, underrepresented minorities (URMs) experience higher attrition than non‐URM counterparts. Informal educational experiences, such as outreach, have been identified to increase URM awareness and enrollment in STEM. The objectives of this work were to (1) elucidate the current state of racial and ethnic diversity in medical physics and (2) provide a community‐focused framework for building effective outreach programs geared toward K‐12 URM students and their families.Strongly disagree to 5 = Strongly agree) that home events increased their career interests in medicine and physics and interest in pursuing STEM coursework.Self‐reported racial and ethnic identity data from the American Association of Physicists in Medicine (AAPM) members were obtained to identify the percentage of URM members. Outreach programming was developed for home or away events. Home events occurred at the University of Wisconsin–Madison Department of Medical Physics; away events occurred at public community institutions that served URM and economically disadvantaged populations. Demonstrations, hands‐on activities, and presentations covered radiation detection, radiotherapy, medical imaging, and medical physics career paths. High school students were asked about their awareness of medical physics prior to outreach events. Likert‐scale surveys evaluated student level of agreement  and were inspired to pursue more STEM courses (73.1%) after the program.Our medical physics outreach program demonstrates a means of increasing awareness and interest around medical physics, particularly for underrepresented individuals. This article addresses gaps in the literature for how to create and implement effective, community‐focused medical physics outreach programs. Additionally, AAPM's most recent diversity statement (PP 30‐B) affirms racial and ethnic diversity as a strength of workforce and efforts to increase diversity in medical physics through active outreach and mentorship are desirable.These initiatives and challenges are not unique to the field of medical physics. Discussions on the importance of DEI have included the enhanced ability for teams to solve complex problems more efficiently, and address how the untapped economic resource prevailing from underrepresented minorities (URMs), inclusive of women, racial and ethnic minorities, and persons with disabilities, may address the projected supply and demand issues within STEM workforces.Community engagement with science through outreach has been shown to be an effective way to increase awareness of various opportunities within science and build relationships with the larger nonscientific community.Although opportunities such as AAPM's Diversity Recruitment through Education and Mentoring summer program have been designed to support URM undergraduate STEM students, specific efforts to increase awareness of and interest in medical physics for a broader student population as documented in the literature are minimal. Fagerstrom et al. demonstrated active‐learning outreach lessons geared toward middle school students that can easily be implemented in community settings .The purpose of this article is to (1) elucidate the current state of racial and ethnic diversity in medical physics through demographic data from professional physics societies and (2) provide a community‐focused framework for building an effective outreach program geared toward K‐12 URM students and their families. Our overall goal was to increase awareness of and interest in medical physics for traditionally underrepresented K‐12 students and build relationships with the larger community. This work may serve as a guide to other medical physicists who hope to directly engage with their communities about the richness of our field and applicability to everyone's lives.2To provide a surrogate measure of URMs in medical physics, self‐reported racial and ethnic demographic data were obtained from the AAPM membership database from 2014 to 2020 courtesy of AAPM HQ. As a means of characterizing entry into medical physics, the percentage of physics bachelor degrees awarded to URMs was obtained from publicly available data from the American Physical Society (APS).With the support of our department, the University of Wisconsin–Madison (UW–Madison) Department of Medical Physics, a graduate student‐led Medical Physics Outreach Committee was formed with the expressed mission of “increas[ing] the visibility of medical physics by teaching community members about the role of physics in medicine as well as the educational and career opportunities in physics‐based careers. [The] focus is directed to the next generation of curious thinkers, especially underrepresented groups in medical physics, by engaging them in conversation and hands‐on medical physics activities.” The Outreach Committee was thus charged with developing activities, choosing engagement opportunities, and organizing outreach events. A generalized workflow of performing an outreach event is provided in Figure Home events were structured to be 3.5‐h‐long field trips, accounting for about half of a school day for participating students. Home events started with a half hour introductory session including an introduction from the department chair, testimonials from current medical physics graduate student volunteers (“volunteers”) about their education and career paths, and a brief overview of the agenda of the field trip. At the conclusion of this session, folders including the agenda, notepad, and pen were distributed to each guest student and teacher participant (“participants”). Visiting participants were then divided into four equally sized, small groups (about four to six participants per group) to rotate through the demonstration stations . Following the full rotation through four prepared demonstration stations , all participants rejoined for an hour‐long lunch and discussion session. During this time, volunteers were encouraged to join participants for lunch. In this way, less structured discussion and time for reflection were facilitated.The Outreach Committee partnered with the Madison Metropolitan School District's Personalized Pathways Program, a local high school improvement strategy with the goal of closing opportunity and achievement gaps,® treatment planning system  was used to explain contouring, treatment planning with conventional linear accelerators, and unique aspects of helical tomotherapy. A hands‐on demo performing megavoltage computed tomography (CT) scans of two phantoms was used to describe image‐guided radiotherapy. The first iteration used a gelatin phantom, made from a low‐cost brain‐shaped gelatin mold (<$5) with a ping pong ball embedded to mimic a resection cavity. The second iteration used a multipurpose chest phantom N1 “LUNGMAN”  with a golf ball inserted to mimic a lung lesion.Home events incorporated as many hands‐on demos as possible at the UW–Madison Department of Medical Physics within a 2‐h window—the target audience being high school students with a foundation of basic physics, biology, and/or medicine. A demo‐heavy tour was created, given its well‐documented positive impact on persistence in STEM education for secondary students.Strongly disagree to 5 = Strongly agree) with the following statements: (1) “As a result of this field trip, my career interests in medicine increased”; (2) “As a result of this field trip, my career interests in physics increased”; and (3) “As a result of this field trip, I am inspired to pursue more STEM courses.” Additionally, high school student participants were asked to provide free‐form text feedback to the questions, “What was your favorite learning experience during the trip and why?” and “What changes would you recommend to make your visit more interesting or effective?” for continual quality improvement of the event.Following all demos, high school student participants were asked to complete surveys using Google Forms to evaluate previous awareness of medical physics and program effectiveness, defined by measuring the event's impact on students’ interest in medicine, physics, and STEM. Three questions were asked on a 5‐point Likert scale in their level of agreement  to detect low levels of radiation from the uranium glaze of red Fiestaware™ produced circa 1930 .A primary outreach lead trained all graduate student volunteers prior to each home and away event to ensure consistent demo, activity, and talk execution. For home events, an hour‐long training was scheduled for all volunteers to discuss outreach best practices and the appropriate level of information for high school students. From experience, best practice guidelines include knowing your audience, connecting content in a way that is meaningful to your audience, and limiting lecture time to promote discussion and hands‐on investigation. Volunteers were assigned to a specific demo station based on expressed interest. During the training session, volunteers assigned to the same demo station were provided time to discuss with each other the plans for the station. The volunteers of each demo station were also tasked with providing a take‐home summary page of their station for the visiting students. For most away events, very minimal training was required. New volunteers were typically trained on‐site during preparation and setup time. They were given the opportunity to first observe an experienced volunteer interact with the audience. Every event was attended by at least one primary outreach lead to ensure volunteers felt supported in engaging with the attendees and to maintain consistency between events.3R2 = 0.94). Of the available membership data, the average percentage of AAPM members identifying as a URM was 10.7%, increasing at a rate of 0.2% per year (R2 = 0.59). The specific distribution of URM and non‐URM AAPM members as a function of year is presented by stacked bar charts in Figure R2 = 0.99).The average response rate of AAPM membership self‐reported racial and ethnic identity data from 2014 to 2020 was 23.6%, increasing at a rate of 2.5% per year (n = 2) and 95.2% (n = 40) were home and away events, respectively. In contrast to home events, the estimated one‐on‐one interaction time between volunteers and participants was approximately 3 min. Overall, 34 different medical physics graduate students volunteered with the Outreach Committee, 19 of whom volunteered at least twice. The average number of volunteers at away events was 2, meanwhile the average number of volunteers for home events was 13. Pictures of demos from both home and away events are provided in Figures Table 5.2% n = 0 were hoThe response rate of the 41 high school students participating in the two home events was 63.4% (26). Home event demographics and survey results from these respondents are presented in Figures 4N = 5487) reported medical physics was a rewarding career (92%) and that they were willing to recommend the profession to others as a career (85%).Medical physics by its nature relies on the diversity of STEM to perform tasks like noninvasive imaging to look inside the human body or treat diseases such as cancer. As indicated by a study from the Center for Health Workforce conducted between 2009 and 2010, a large sample of medical physicists in the United States  were not aware of medical physics; furthermore, this statistic may even be inflated due to social desirability bias of knowledge in this captive audience and/or due to participants geographic proximity to our graduate program.Opportunities for creation and growth of medical physics outreach programs are numerous. For events hosting large groups  such as in many away events, the short interaction times limited the means of program evaluation. In the case of away events with smaller groups, assessments similar to the work by Poole et al. were used for the purpose of program improvement and volunteer training development.In terms of away events, preliminary experiences required coordination to borrow equipment . By merely demonstrating high‐volume interactions through photographs, the Outreach Committee was able to secure a portable ultrasound system on loan from a vendor for dedicated outreach purposes. Communicating these efforts with the rest of the department encouraged faculty and staff to share or loan equipment for demonstrations and activities. These events would not have been possible without the support of the department at large. Anecdotally, graduate student outreach volunteers frequently remarked that participating as volunteers felt personally rewarding and generated enthusiasm for volunteering at upcoming events. Identifying the opportunities for growth, subsequent needs of an outreach program, and identifying volunteers and community partners are crucial for effective execution.https://www.aapm.org/education/ERG/PUBLICED/). Two additional resources for creating effective science outreach programs are included for convenience: (1) Bevan et al. with the Center for Advancement of Informal Science Education highlight important considerations and intentions when developing a science outreach programIn translating medical physics outreach to the broader community, it is important to recognize and identify the resources and community in which one finds themselves. Regarding resources, the majority of the equipment used in outreach programming are accessible from clinics, universities, or are of low cost. However, it is recognized that the use of clinical equipment at away events may not be feasible. In these circumstances decommissioned, nonclinical equipment used for qualitative demonstrations may be a more viable option. As it pertains to home events, the UW–Madison Department of Medical Physics represents a unique institution, with a variety of equipment dedicated for research. Consequently, challenges pertaining to patient privacy pose less of a barrier in this environment for outreach program implementation as compared to a clinic. When translating home events to clinical environments, permission slips could include language to maintain HIPAA compliance, notably the importance of patient privacy and asking students to refrain from photography during their visit. It is worth noting the increased number of average volunteers at home events is a testament to the additional work and support that home events require. As it pertains to away events, medical physicists who find themselves in rural communities or far from community centers have challenges identifying community events and/or partners similar to those indicated in this article. To overcome these obstacles, away events can occur at ubiquitous public institutions such as libraries and schools or existing STEM networks such as the National Girls Collaborative Project can be used to identify larger ongoing STEM efforts in one's own community.5Community‐focused medical physics outreach programs for K‐12 students are effective at introducing and inspiring students to pursue careers in STEM and medicine. In alignment with AAPM's strategic goals and placing importance on DEI, outreach programs such as these also foster good community relationships and hold space for discussion and exploration, contributing to participants’ perceptions of science and STEM literacy. Although facilities at large academic institutions present unique opportunities, implementation of medical physics outreach programs from individuals or smaller institutions is quite feasible. As individuals, we play a role in shaping the field we want to see and influence the next generation of medical physicists.The authors declare no conflict of interest.AS and CL designed the project. AS, SJ, and CL contributed to acquisition of data. AS and SJ performed data analysis. AS drafted the manuscript. All authors read, revised, and approved the final manuscript.


Extracellular vesicles (EVs), mainly exosomes and microvesicles, are bilayer lipids containing biologically active information, including nucleic acids and proteins. They are involved in cell communication and signalling, mediating many biological functions including cell growth, migration and proliferation. Recently, EVs have received great attention in the field of tissue engineering and regenerative medicine. Many in vivo and in vitro studies have attempted to evaluate the chondrogenesis potential of these microstructures and their roles in cartilage regeneration. EVs derived from mesenchymal stem cells (MSCs) or chondrocytes have been found to induce chondrocyte proliferation and chondrogenic differentiation of stem cells in vitro. Preclinical studies have shown that exosomes derived from MSCs have promising results in cartilage repair and in cell‐free therapy of osteoarthritis. This review will focus on the in vitro and in vivo chondrogenesis and cartilage regeneration of EVs as well as their potential in the treatment of osteoarthritis. They are divided into three major groups: hyaline, fibrous and elastic cartilages. Hyaline cartilage is the most frequent form and is found in synovial joints, ribs, nose, trachea, bronchi, etcOsteoarthritis (OA) is characterized by progressive cartilage damage and is the most prevalent cartilage‐related disease. OA mainly affects elderly people and is more prevalent in women than men.2The secretome includes extracellular vesicles (EVs) and is secreted from many cell types.+ lymphocytes and increase the secretion of inflammatory cytokines.Exosomes are present in the synovial fluid (SF); however, the quantity and compositions of SF‐exosomes and more importantly their functions are changed in cartilage‐related diseases. Studies have shown a higher levels of exosomes in patients with early and late‐stage OA than in the normal population.Recently, many studies have evaluated the potential use of exosomes as diagnostic markers as well as carriers of genes for the therapeutic purpose.3et al showed that MSC‐derived exosomes promote proliferation and chondrogenic differentiation of tendon stem/progenitor cells (TSPCs) into mature chondrocytes.et al showed that MSC‐derived exosomes and microparticles can protect osteoarthritis‐derived murine chondrocytes in vitro and in vivo. It was found that exosomes from murine bone marrow–derived MSCs (BM‐MSCs) increased the expression of chondrocyte markers including aggrecan and type II collagen. On the other hand, exosomes inhibited the expression of immune and inflammatory elements responsible for cartilage degradation such as matrix metalloproteinases (MMPs). The exosome‐activated chondrocytes were not able to activate CD4+ and CD8+ T lymphocytes and B lymphocytes in vitro.et alIn the field of cartilage tissue engineering, iPS and various sources of MSCs have been widely used to differentiate into mature chondrocytes.et alIt is well known that exosomal miRNAs mediate many functions of exosomes such as cell proliferation and differentiation as well as inhibition of cell apoptosis.et al evaluated the expression pattern of exosomal microRNAs during chondrogenesis of human bone marrow stem cells (hBMSCs). They found that 35 miRNAs are up‐regulated during chondrogenesis including miR‐320c. Subsequently, they transfected hBMSCs with miR‐320c and found that hBMSC‐320c‐Exos are more powerful in chondrocyte proliferation and chondrogenic differentiation of hBMSCs.Hao Sun Chondrocyte‐derived exosomal miR‐8485 was also found to induce BM‐MSC differentiation into chondrocytes. miR‐8485 targets GSK3B (glycogen synthase kinase 3 beta) that finally activates Wnt/β‐catenin pathway and promotes stem cell differentiation into chondrocytes.et al used blood‐circulating exosomes to transfer miR‐140 into rabbit BM‐MSCs. They showed that exosomes themselves or in a combination with miR‐140 promote chondrogenic differentiation of rabbit BM‐MSCs. Of note, miR‐140 increased the chondrogenic inductivity of exosomes.In the other study, Gi Won Lee 4MSCs have been known to promote cartilage repair and chondrocyte differentiation through a paracrine effect via cytokine secretion. These factors including transforming growth factor beta (TGF‐β) and hepatocyte growth factor (HGF) constitute a major part of MSCs secretome.4.1et al implanted rabbit CPC (cartilage progenitor cell)‐alginate subcutaneously in mice. Thereafter, exosomes derived from chondrocytes (CC‐Exos) or BMSCs (BMSC‐Exos) were found to be transplanted at the site of implantation. Twelve weeks following implantation, stable cartilage tissue with a high amount of collagen deposition and low vascular ingrowth was observed.et al, KGN‐preconditioned small EVs induced transplanted hUCMSCs to differentiate into functional chondrocytes in rabbits with full‐thickness cartilage defects. This induction was attributed to the overexpression of miR‐381‐3p in KGN‐sEVs.Besides the in vitro chondrogenesis role of EVs, some studies have tried to evaluate their potential in the induction of chondrocyte differentiation in animal models. Chen et al showed that the controlled release of BMSC‐Exos at rat tendons induces the proliferation, migration and differentiation of endogenous tendon stem/progenitor cells (TSPCs) in rat patellar tendon defect model. Following the exosomes‐fibrin injection, a neo‐tendon with a high expression of mohawk, tenomodulin and type I collagen was formed at the site of the defect.et al also showed that the human MSC‐derived exosomes induce the proliferation of chondrocytes and inhibit their apoptosis in an OA rat model. They showed that non‐coding RNAs including lncRNAs and miRNAs are involved in this phenomenon.et al reported that miR‐92a‐3p‐overexpressing exosomes enhance in vivo chondrogenesis and inhibit cartilage degradation by targeting WNT5A in collagenase‐induced mouse model of OA.et alYu 4.2et al following MSCs‐exosome injection, suggesting the role of exosomes in increasing chondrocytes proliferation in an immunocompetent rat osteochondral defect model. Notably, no inflammation and destructive immune reactions were observed in the rats treated with human MSC‐derived exosomes, showing the importance of cell‐free therapy using EVs.et al reported that the exosomes derived from human MSCs are capable to induce chondrocyte proliferation and inhibit cell apoptosis in the collagenase‐induced rat model of OA.The inflammation and oxidative stress in OA cause ECM and cell destruction and loss. Thus, an increase in cell numbers and subsequently an increase in ECM biosynthesis can reduce the OA‐related complications.et al confirmed the role of the CD73‐Akt/Erk pathway in exosome‐mediated cell proliferation. They showed that the blocking of this pathway by a CD73 inhibitor (AMPCP) and theophylline (an antagonist of adenosine receptor) decreases the number of chondrocytes; however, the matrix synthesis remains unchanged.et al also showed that exosomes derived from MSCs inhibit chondrocyte apoptosis via p38, ERK and Akt pathways, thereby increasing the chondrocyte frequency.Mechanistically, exosomes have been found to mediate cell proliferation through Akt and Erk1/2 signalling pathways,4.3et al showed an elevated intracellular ATP level in exosome‐treated chondrocytes,The destruction and dysfunction of mitochondria decrease cell bioenergetics and play a major role in the pathogenesis of OA. It is shown that chondrocytes from OA patients have a lower level of bioenergetics due to reduced mitochondrial biogenesis and decreased mitochondrial electron transport chain (ETC) proteins. A study by Zheng and coworkers showed that exosomes from primary chondrocytes cultured in normal culture contain more mitochondrial proteins than those derived from OA inflammatory environments.4.4+ regenerative M2 macrophages support the chondrocyte functions, while CD86+ M1 macrophages produce a high amount of pro‐inflammatory cytokines including IL‐1β and TNF‐α.Inflammation is known to be involved in the initiation and development of OA disease.et al showed that exosomes derived from human embryonic stem cell–derived MSCs induce more infiltration of M2 macrophages into the synovial fluid in an immunocompetent rat model.et al also reported that exosomes derived from amniotic fluid stem cells (AFSC) change the polarization of macrophages into M2 type. They showed that either MSCs or their exosomes reduce the inflammatory cytokines in an animal model.Since inflammation plays a major role in the pathogenesis of OA, inhibiting inflammatory responses could be helpful in cartilage repair.5et al tried to define the expression pattern of exosomal miRNAs during chondrogenesis of BM‐MSCs. They analysed and compared the exosomal miRNAs in BM‐MSCs before and after chondrogenic induction. The microarray data showed that more than 140 miRNAs differentially express by over a twofold change. It was indicated that the expression levels of miR‐1246, miR‐1290, miR‐193a‐5p, miR‐320c and miR‐92a are highly up‐regulated, while the expression levels of miR‐377‐3p and miR‐6891‐5p are dramatically down‐regulated. They also found that the exosomes derived from miR‐320c‐overexpressed MSCs are more potent than normal MSC exosomes in chondrocyte proliferation and matrix deposition.Exosomal miRNAs have been found to induce the proliferation and differentiation of stem/progenitor cells into chondrocytes.6Many studies indicated the potential role of exosomes in chondrogenesis and cartilage regeneration. Exosomes derived from both chondrocytes and MSCs have been found to induce the differentiation of progenitors and stem cells into mature chondrocytes in vitro. These exosomes have also a capability in the induction of cartilage endogenous stem/progenitor cells to migrate, proliferate and differentiate into chondrocytes in vivo. Exosomes derived from MSCs increase the chondrocyte proliferation and bioenergetics level in the damaged cartilage. They also increase the level of anti‐inflammatory and immunoregulatory cytokines and molecules, and decrease the level of inflammatory cytokines. Therefore, the use of exosomes from MSCs, as a cell‐free therapeutic option, has a great potential in the treatment of OA and other diseases characterized by cartilage damage and chondrocyte loss. However, more studies are needed to evaluate the exact mechanisms of exosomes during cartilage repair. Nevertheless, there are some limitations that should be further considered. The efficient isolation and purification of exosomes are still a challenging task. In some cases, the atrophy of cartilage has been observed following MSC‐derived exosome transplantation. Moreover, sufficient cartilage regeneration is challenging when exosomes from various sources were transplanted.We wish to confirm that there are no known conflicts of interest associated with this publication and there has been no significant financial support for this work that could have influenced its outcome.


In social species, reproductive success and rates of dispersal vary among individuals resulting in spatially structured populations. Network analyses of familial relationships may provide insights on how these parameters influence population‐level demographic patterns. These methods, however, have rarely been applied to genetically derived pedigree data from wild populations.Rangifer tarandus caribou) in Saskatchewan, Canada, to inform recovery efforts. We collected samples from 933 individuals at 15 variable microsatellite loci along with caribou‐specific primers for sex identification. Using network measures, we assess the contribution of individual caribou to the population with several centrality measures and then determine which measures are best suited to inform on the population demographic structure. We investigate the centrality of individuals from eighteen different local areas, along with the entire population.Here, we use parent–offspring relationships to construct familial networks from polygamous boreal woodland caribou , assessing the contribution of individual caribou to the population with several centrality metrics and determine which metrics are best suited to inform on population demographic structure. The familial network revealed that boreal caribou in Saskatchewan form a complex, interconnected social network, and identified areas of higher fitness levels and social cohesion across the range in support of population monitoring and recovery efforts.Network analyses of familial relationships may provide insights on how fitness influences population‐level demographic patterns in socially structured populations. Here, we use networks to reconstruct parent‐offspring relationships and create a familial network from polygamous boreal woodland caribou ( Then, we create a spatial familial network to identify local area networks with varying distributions of centrality measures, determining whether high centrality measures and edge‐to‐node ratios at the fine scale correspond to high centrality in the full network. Spatially analyzing familial networks is inherently difficult due to the presence of inferred individuals, whose spatial locations are unknown. By using the centrality measures from the aspatial network in the spatial network of individuals, the network connections to the inferred individuals can be brought into a spatial framework. We also assess the structure and cohesiveness within the full network using edge removal to identify boundaries that run between subgroups . 1,970 were successfully scored (average success rate of 91.4%), and 933 unique individuals were identified Table . We used3.13.1.1We identified 18 local area networks in order to determine the cohesiveness and centrality of individuals. The local areas with the lowest edge‐to‐node ratios were all located in the northern part of the Boreal Shield, with the high edge‐to‐node ratio areas found further south in the western part of the Boreal Plains and southern part of the Boreal Shield Figure . We founWhen bringing in the first neighbors of all individuals within a local area, the high edge‐to‐node ratio areas formed a tighter cluster of individuals than in the low edge‐to‐node ratio areas. Including first neighbors in the area with the highest edge‐to‐node ratio (Canoe Lake) increased the ratio to 1.14 and connected 73.6% of individuals into one cluster Figure . A large3.1.2Individuals from high edge‐to‐node ratio local areas were located more centrally within the full family network and clustered with other individuals from the same local area. Individuals from low edge‐to‐node ratio local areas were dispersed throughout the network and primarily found on the outer edges of the network Figure . AlthougRemoval of edges with high betweenness did not alter the overall network structure Figure . Most ed4Network analyses have been used in biological and ecological studies to quantify and explore the structure of populations across numerous taxa , with higher fitness females having higher fecundity and earlier offspring date of birth than lower fitness females  defined by an association index , with edges representing observed relationships, forming an interaction network ; Formal analysis (lead); Investigation (lead); Methodology (lead); Software (lead); Visualization (lead); Writing‐original draft (lead); Writing‐review & editing . Micheline Manseau: Conceptualization ; Data curation ; Formal analysis (supporting); Funding acquisition (lead); Investigation (supporting); Methodology (lead); Project administration ; Supervision (lead); Validation (supporting); Writing‐review & editing (lead). Paul Wilson: Conceptualization (supporting); Data curation ; Funding acquisition (lead); Project administration (lead); Resources ; Supervision ; Writing‐review & editing .https://doi.org/10.5061/dryad.zkh189385This article has earned an Open Data badge for making publicly available the digitally‐shareable data necessary to reproduce the reported results. The data is available at Supplementary MaterialClick here for additional data file.


Accountability is of universal interest to the business ethics community, but the emphasis to date has been primarily at the level of the industry, organization, or key individuals. This paper unites concepts from relational and felt accountability and team dynamics to provide an initial explanatory framework that emphasizes the importance of social interactions to team accountability. We develop a measure of team accountability using participants in the USA and Europe and then use it to study a cohort of 65 teams of Irish business students over three months as they complete a complex simulation. Our hypotheses test the origins of team accountability and its effects on subsequent team performance and attitudinal states. Results indicate that initial team accountability is strongly related to team trust, commitment, efficacy, and identifying with the team emotionally. In established teams, accountability increases effort and willingness to continue to collaborate but did not significantly improve task performance in this investigation. Accountability is prevalent in the ethics literature because it makes people attend to the relevant prescriptions for conduct and provides a mechanism for the social control of behavior in accord with those prescriptions  that addresses limitations in existing accountability measurements . Based on our results, our third contribution is to establish collective team accountability as a coherent emergent state and to demonstrate its relationship with team trust, commitment, affective identification, and team efficacy. Our fourth contribution addresses practical concerns about collective accountability. Presumably getting collective accountability ‘right’ matters because it should inhibit social loafing, increase performance, and reduce turnover intentions, all outcomes that are valued by organizations. We therefore examine whether team accountability indeed predicts collective effort, task performance, and willingness to work together again (Study 2).An often made point in the ethics literature and observations of business practices is that even the most carefully conceived accountability mechanisms do not always lead to accountable behaviors by individuals or organizations , rather than an objective state of affairs .Our research process therefore started by developing and validating a team accountability questionnaire that could work across organizational levels. In a conceptually valid measure of shared team accountability the primary accountability actor is the group , the audience to whom the team is accountable includes its members, and the content assesses collective expectations about explaining and justifying team decision processes and performance, as well as team dynamics related to relational accountabilities. We followed deductive scale development processes to generate an initial set of items Hinkin,  because individual accountability literature might not fully capture the ongoing team member interactions we had theorized were essential to formal accountability demands being interpreted and internalized. For that reason we wrote five additional items specific to team processes that would reinforce perceptions of being accountable to each other.A search of the accountability literature identified 120 individual accountability items that could be shifted to the level of the team by changing the referent from ‘I’ to ‘we’ and by changing the content to reflect shared expectations Chan, . We whitidentification . Participants responded to an electronic survey link. Items were assessed by participants indicating the extent to which they agreed or disagreed with a given statement where 1 = strongly disagree to 7 = strongly agree.α) of 0.90. Item means and correlations with theoretically related scales are reported in Table SPSS was used to evaluate the most suitable items from our list of 27 possible candidates. Redundant items and those that exhibited low inter-item correlations were discarded. We screened out accountability items that correlated too highly or not enough with team trust, identification, commitment, and viability. Corrected item-scale correlations were inspected and several more cuts were made to ensure retained team accountability items were representative of the whole theoretical domain. The eight selected items of the Team Accountability Questionnaire (TAQ) indicate a coefficient alpha  to examine the convergent and discriminant validity of the TAQ. Large samples are always beneficial; however, when factors are well defined or their number is limited, small sample size EFA can yield reliable solutions  which indicates a solid factor  of the measure is 0.86 in this sample.Each respondent reported on the accountability behaviors of their particular leadership team. The eight items from the piloted questionnaire were slightly modified to suit the organizational context . Response options ranged from 1 = strongly disagree to 5 = strongly agree. Coefficient alpha  to examine the convergent and discriminant validity of the TAQ. 217 participants were recruited from an online commercial survey pool  and received $1.00 in compensation for completing our questionnaire. The average age in the sample is 39 years. Slightly more than half of the participants were female and 28 percent consider themselves minority. Participants have been with their current employer for an average of eight years and with their primary team for an average of 16 months. Eight-eight percent indicated they interact daily or hourly with their team members.α = 0.88), trust was measured with four items  = 20.77, n.s., comparative fit index (CFI) = 0.99, and standardized root mean square residual (SRMR) = 0.02  = 143.83, CFI = 0.93, SRMR = 0.05) fits the data much better than a single-factor model (Δ χ2(1) = 231.31, p < 0.001). Similarly a two-factor model of team accountability and team commitment (χ2(64) = 163.06, CFI = 0.94, SRMR = 0.05) fits the data better than a single-factor model (Δ χ2(1) = 176.198, p < 0.001).A two-factor model of team accountability and team trust . Taken together, these results suggest that team accountability as measured by the TAQ is a unique construct.As part of our CFAs, we also explored the correlation between latent variables and found the latent variables to be related but not overly so . Participants were randomly assigned to a team. Membership was further stratified by gender and nationality to ensure each team included a randomly assigned woman and international student. All teams had 4 to 5 members except one team with only 3 members. These teams operated under identical formal accountability structures, were given the same team task, started and worked together for the same amount of time, and had similar resources at their disposal. Naturally controlling for these contextual features was deemed more valuable in testing our hypotheses about collective accountability than the external validity gained by conducting our research in a professional setting, particularly when business students have the requisite understanding to respond knowledgeably to basic issues such as their own team dynamics . Average team performance in the final quarter of the stimulation was 62.5 . Due to skewness and kurtosis, the square root of the data is used in our analyses of financial performance. Several teams operated at a loss, so a constant was added to the original data to ensure the lowest value was equal to one prior to taking the square root.We used financial performance in the simulation to operationalize overall Effort as a measure of team effectiveness was measured as the time the team invested in the task. The simulation platform collected this data through the time each team member spent actively on the platform. We divided time spent on the platform by team size to account for the number of persons available to contribute to the task. During the fourth quarter, the average team member was spending 12.0 h on the platform , and during the final quarter, the average team member was spending 10.6 h on the platform . A logarithmic transformation was implemented as the data were markedly positively skewed.SPSS was used to test our hypotheses. Analyses are reported at the level of the team unless noted otherwise. The rationale for this approach is that we are predicting team-level outcomes from team-level inputs as that matches our theoretical viewpoint of team accountability. We recognize that there is room for debate over whether this is the most accurate way to represent accountability at the beginning of the team lifecycle as some teams may have crystalized collective perceptions more quickly than others; however, our measurement and conceptualizations were at the team level so we report those analyses. Also, in the study environment teams received clear, uniform, and periodically reinforced formal accountability expectations which should have accelerated the sharedness of group accountability perceptions. In general, we found that relationships between constructs are stronger at the individual level than at the team level, so using team-level data yields more conservative estimates. Table β = 5.83, SE = 0.08, t = 74.95, p < 0.001), the descriptive statistics indicates that average accountability across the subsample of 46 teams with complete data does not vary much with time, i.e., Time 1 Mean = 5.83, Time 2 Mean = 5.83 and Time 3 Mean = 5.88. An evaluation of the accountability within these 46 teams indicates that neither the linear nor quadratic polynomial growth rates are significant in explaining team changes in accountability over time. Random coefficient modeling with time as a repeated measurement at Level 1 and team membership as a Level 2 effect suggests that accountability does not appear to change much over time within teams. Bliese , commitment (r = 0.45), affective identification (r = 0.58), and collective efficacy (r = 0.55) during the initial stages of team collaboration. The first hypothesis is therefore supported. Formative team accountability perceptions are part and parcel of other positive emerging team attitudes.Hypothesis 1 states that initial team accountability during team development should emerge hand in hand with team (a) trust, (b) affective identification, (c) commitment, and (d) collective efficacy. The data indicate a strong positive relationship between initial team accountability perceptions and trust (r = 0.85), therefore we added them together in a single linear composite to reduce collinearity. Regression results are reported in Table Our next set of hypotheses examined the ability of ‘established’ accountability at the project midpoint to predict subsequent team outcomes. We assumed that end point values of the dependent variables are in part a function of their midpoint values at time 2. For example, final performance is in some ways constrained by midpoint performance. Although including lagged dependent variables often decreases coefficient estimates for the independent variable of primary interest and has been argued to unduly suppress the explanatory power of the independent variable, we included interim trust, commitment, performance, and effort as lagged dependent variables to provide a less biased test of the hypothesized relationship between accountability and subsequent team effectiveness and attitudes . The strongest predictors of team performance are previous performance (β = 0.36) and effort (β = 0.43). In support of Hypothesis 3, we found team accountability is associated with a significant increase in team effort .Hypotheses 2 and 3 predict positive effects of team accountability on team performance and effort. Hypothesis 2 does not receive strong support. Our data find that accountability is positively related to subsequent team performance, but is not a statistically significant predictor when added to a model that includes midpoint performance . Support for Hypothesis 5 is mixed. Accountability is positively associated with later trust (H5a) but this effect is not statistically significant  when added to model with midpoint trust and commitment. The strongest predictor of trust is previous trust and commitment (β = 0.39). Although support is limited for Hypothesis 5a, Hypothesis 5b is supported: midpoint team accountability predicts subsequent team commitment .2The data support Hypothesis 4, that team accountability is associated with greater viability (Our approach follows a relational understanding of accountability because we position team accountability as an emergent understanding of how things are done on a team that depends in large part on multiple evolving subjectivities rather than formal accountability structures. We agree with the view that a team is a ‘forum’ for moral tensions that often must be worked through by the members themselves Sewell, . Our datFollowing a team over time allows us to develop a construct of team accountability that embraces the social processes through which ‘thick’ ethical norms are socially constituted (Islam & Greenwood, Two results were unexpected. First, collective team accountability did not predict trust when we included lagged variables. Our inquiry was not intended to identify the strongest predictor of trust, but rather to test whether accountability measurably increased subsequent trust. One explanation for the lack of a relationships is statistical, namely that interim trust and accountability are highly correlated predictors and this makes it difficult for accountability to add predictive value in the hierarchical model. A more theoretical explanation is that once teams are up and running, trust is established and the strongest predictor of future trust is trust itself.A second unanticipated result is that accountability did not meaningfully predict financial performance when previous performance and effort were included as predictors. Fostering a sense of collective accountability is often intended as a managerial tool for driving organizational objectives and reducing loafing behaviors. In our study, team accountability exhibited stronger ties to emergent and affective team states than to subsequent performance. In other words, accountability expectations are not a performance panacea, although they do encourage greater time investment in shared goals and precede measurable improvements in some dimensions of concrete task performance.outside the control of the team (de Leede et al., It is possible our results were limited by the number of teams in our sample size or by using a single number to encapsulate performance, but our interpretation is that ultimate performance is often somewhat Accountability is a sprawling theme that crosses disciplinary and methodological boundaries. The primary contribution of this study is to weave together philosophical ethics, management, and social psychology theories to explain the emergence, coherence, and consequences of teams developing a sense of accountability. By uniting a philosophical understanding of relational accountability (Painter-Morland, Journal of Business Ethics in 2020 surfaced 183 abstracts for original research on accountability published since 1982. Over half of this work has been published in the past 10 years, suggesting an increase in scholarly interest. However, only two of these articles specifically examined ethical issues related to the accountability of teams (de Leede et al., Detailed learning about team accountability matters because autonomous and empowered teams are increasingly seen as the basic building block of agile organizations (Deloitte, Two practical limitations to understanding the intricacies of team accountability are the lack of an appropriate measurement instrument and the use of phantom or ephemeral teams (Hall et al., Our findings highlight that even within a highly structured accountability environment, accountability varies. Accountability policies and procedures are filtered through a subjective lens so managers should not expect teams to react identically to the same policies and procedures. For example, formal accountability features are often open to misinterpretation despite frequent verbal and written cues (Patchan et al., Our findings also suggest that initial levels of group accountability persist, so managers should support initial team interactions because they may count ‘extra’ in forming shared perceptions. If you seek a direct lever to improve team performance, look elsewhere, particularly when future performance is contingent on performance at previous levels. Accountability appears to serve the team best by increasing effort, viability, and deepening commitment.and evaluative (Islam & Greenwood, This study maps new territory and as such merits refinement and extension. We examine the relationship between relational accountability and team dynamics which is an essential step, but developing team accountability as a ‘thick’ rather than ‘thin’ ethical concept requires being descriptive We also call for expanded outcome variables beyond the usual suspects. Based on research that connects workplace cultures of love and anger to employee loneliness (Ozcelik & Barsade, Future theory building could build bridges between shared team accountability and the formalistic or utilitarian ethical orientation of a team (Adler et al., Unraveling the connection between leadership and collective accountability is also worth exploring. We utilized self-managed teams in which leadership emerges organically. However, in organizations with hierarchical structures and leader/subordinate relationships, team accountability may arise as a substitute for strong team leadership, or strong leadership may be the driving force behind initial differences in team accountability perceptions. Furthermore, teams are likely to develop different types of accountability perceptions depending on the quality of their relationship with an external leader. For example, when mutual respect is absent or lost, a leader is more likely to lean on formal control mechanisms. In response, the team may limit accountability perceptions to the obligations specified. In contrast, when a team and leader form an emotional attachment and have positive mutual regard, accountability perceptions are more likely to be internalized (Erdogan et al., Accountability as a shared team characteristic has been explicitly incorporated into our theorizing and the subsequent measurement strategy is aligned with this conceptualization, i.e., the TAQ is based on a referent shift model and many of our analyses use the team mean Chan, . This apA strength of our research design is that we are able to examine accountability over the team’s lifespan in a highly controlled situation with fixed external accountability measures and leadership, identical performance challenges and timelines, objective measurement of performance and effort, and by teams of similar demography, size and experience. The effects of these factors would have been difficult to control for in a corporate setting, but the simulation and academic context we use cannot realistically mirror the intensity of ‘real world’ accountabilities. Team accountability may well be reliably predictive of task performance when performance accompanies meaningful financial and professional implications or is measured along multiple dimensions rather than reduced to a single metric as in this study. Future research should explore the connection between team accountability and performance in contexts with higher stakes.This paper unites concepts from relational and felt accountability and team dynamics to provide an initial explanatory framework of team accountability and a measurement instrument that can be used in practice and research to continue this work. If accountability is the glue that holds together organizations, and teams are the organizational unit of necessity and choice, then perceptions of team accountability are worthy of intense attention across disciplines.


Non‐biological childhood mortality sex ratios may reflect community sex preferences and gender discrimination in health care.We assessed the association between contextual factors and gender bias in under‐five mortality rates (U5MR) in low‐ and middle‐income countries.Full birth histories available from Demographic and Health Surveys and Multiple Indicator Cluster Surveys (2010‐2018) in 80 countries were used to estimate U5MR male‐to‐female sex ratios. Expected sex ratios and their residuals (difference of observed and expected) were derived from a linear regression model, adjusted for overall mortality. Negative residuals indicate more likelihood of discrimination against girls, and we refer to this as a measure of potential gender bias. Associations between residuals and national development and gender inequality indices and with survey‐derived child health care indicators were tested using Spearman's correlation.Mortality residuals for under‐five mortality were not associated with national development, education, religion, or gender inequality indices. Negative residuals were more common in countries where boys were more likely to be taken to health services than girls .Countries where girls were more likely to die than boys, accounting for overall mortality levels, were also countries where boys were more likely to receive health care than girls. Further research is needed to understand which national characteristics explain the presence of gender bias, given that the analyses of development levels and gender equality did not discriminate between countries with or without excess mortality of girls. Reporting on child mortality separately by sex is required to enable such advances. Which national characteristics—including indicators of levels of development, gender inequality, or gender bias in childcare—can predict male‐to‐female sex ratios in under‐five mortality, after adjusting for total morality level?Sex ratios in under‐five mortality rates vary around the world, according to overall levels and causes of mortality, and to the presence of gender bias. Contextual factors associated with sex differentials in mortality have been explored, but so far studies failed to take overall mortality levels into account.After adjustment for total mortality, higher‐than‐expected female mortality was found in countries where there was also evidence of gender bias in care‐seeking for common illnesses.1Sex differences in mortality are observed along the life cycle in association with various biological and social factors.Under circumstances where boys and girls are equally valued and health care is evenly available to both sexes, boys have higher mortality rates than girls due to biological differences.The survival advantage of girls becomes more evident as overall mortality falls because perinatal causes and malformations, which represent the leading causes of death when mortality is low, predominate among male infants.Documentation of sex ratios according to mortality levels can be used to identify where potential gender bias in childhood mortality exists. Over the past decades, different approaches and methods have been used for assessing the presence of excess female deaths based on overall or male mortality rates.Some authors explored multiple contextual factors associated with sex differentials in childhood mortality, including socio‐economic development level and measures of gender discrimination, but failed to take the overall level of mortality into account in their analyses.In this article, we address an issue that has not been previously investigated in the literature in multiple countries. After adjusting sex ratios by overall under‐five mortality rates, we assessed whether differences between observed and expected sex ratios may be predicted by national indices of development and gender inequalities, or by survey‐based measures of gender bias in child health care.22.1http://dhsprogram.com and http://mics.unicef.org, respectively), which had information on full birth histories for women of reproductive age.We analysed data from nationally representative Demographic and Health Surveys (DHS) and Multiple Indicator Cluster Surveys (MICS) carried out in LMICs from 2010 onwards. For countries with more than one survey, we selected the most recent. These surveys collect comparable data across countries based on standard questionnaires. We aimed to include all surveys with public‐domain data sets available on the DHS and MICS websites  and Gender Inequality Index (GII), from UNDPBecause information on contextual variables is not available for all calendar years, we used data for the closest year to the mid‐point of the 10‐year interval over which births were studied in each survey, that is 5 years before the survey date.The assessment of factors potentially associated with gender bias in U5MR was complemented by analyses using child health care indicators available from the same surveys used for mortality estimates, in order to investigate whether the sex ratio in mortality could be related to the sex ratio in health care utilization. The following indicators were analysed: (a) care‐seeking for common childhood symptoms: proportion of children under 5 years of age who presented with symptoms of pneumonia , fever, or diarrhoea in the 2 weeks prior to the interview and were taken to an appropriate health care provider ; (b) full immunization coverage: proportion of children aged 12 to 23 months who received at any age all the following vaccines: one dose of BCG , three doses of DPT  or tetravalent/pentavalent vaccine, three doses of polio, and at least one dose of measles ; and (c) postnatal care for babies: proportion of last‐born children under 2 years of age who received any health check‐up within two days after birth.2.4Linear regression was used to model the association between U5MR sex ratio and total U5MR (for both sexes combined). The analyses included all countries for which mortality data were available. Sex ratio residuals were estimated for each country as the difference between observed and predicted values from the regression model. We refer to residuals as a measure of potential gender bias, as positive values indicate higher mortality than expected among boys than girls, which we interpret as a lower likelihood of discrimination against girls. Negative residuals signal higher‐than‐expected female mortality and thus indicate the presence of potential gender bias disadvantaging girls.Next, we tested the association of covariates with the above‐mentioned residuals, using Spearman's correlation coefficient due to the non‐normal distribution of the variables.2.5Sensitivity analysis is presented in the supplementary materials and includes estimates of sex ratio residuals for countries according to the methods proposed by Alkema et al.Additional sensitivity analyses included repeating the main correlation analysis for a subset of 52 countries with information on all explanatory variables with 70 or more data points, thus excluding four of the original set of 22 variables.All analyses were carried out in Stata 15 . The agencies responsible for the surveys provide in each data set the sampling weights, based on selection probability, and adjusted for non‐response, which ensure the representativeness of the sample and are used to correct for the under‐ or over‐sampling of different strata during sample selection. The country‐ and sex‐specific mortality rates estimated from these data sets account for the complex survey design, including sampling weights and the clustered nature of the data. More information about the estimation and use of sampling weights is available elsewhere.2.6Ethical clearance was obtained by the national agencies responsible for each survey and all identifying data are omitted guaranteeing participants’ anonymity.3A total of 82 countries had information on mortality rates by sex. We removed two countries identified as outliers from the analyses for U5MR (Albania and Armenia); the results for the complete data set including these two countries are presented in the Supplementary Materials Figure  and the Figure P‐value of .124, presenting no evidence that residuals were not normally distributed. Supplementary Figure Potential gender bias against girls is observed when residuals are negative, reflecting lower‐than‐expected sex ratios after adjustment for total U5MR, that is fewer deaths of boys and more deaths of girls than would be expected. Residuals of U5MR sex ratios ranged from −43.7 to 34.5 . Skewness and kurtosis test for normality showed a The rank correlation coefficients between the residuals with explanatory variables at national level are presented in Table Next, we tested associations between the residuals and sex ratios for three child health care indicators derived from the same surveys. There was no evidence of associations with sex ratios in postnatal care or full immunization coverage. However, the male‐to‐female ratio in care‐seeking for common diseases  was associated with mortality residuals in the expected direction (Figure 44.1Our findings confirm prior research showing that the male‐to‐female sex ratio in mortality is inversely associated with overall U5MR level.4.2We presented a novel approach by quantifying potential gender bias through residuals of the sex ratio for mortality, adjusted for overall mortality level. When residuals are positive, the mortality of boys is higher than would be expected based on the mortality of girls, thus suggesting that gender bias against girls is unlikely. Our approach incorporates variability in sex ratios due to causes of death and adjusts for the biological female advantage in survival. Instead of using a fixed value for the expected sex ratio, we were able to model such ratios according to the overall mortality level, leading to estimates of expected sex ratios for a set of LMICs and allowing us to calculate residuals.4.3Some limitations ought to be recognized. Estimation of mortality rates for children is based upon maternal recall of births and deaths obtained in household sample surveys and may be affected by recall bias, misdating errors, and omission.It is also interesting to highlight the case of Armenia, found to be an outlier in the distribution of sex ratios by overall mortality. The country presents a low fertility rate, low mortality level, and documented discrimination against girls.Additionally, some degree of survival bias may exist when assessing coverage with child health interventions, because these questions are asked for children who are still alive, and gender bias in mortality may have already happened. Childhood mortality sex ratios may also be affected by sex‐selective abortions, which would restrict the number of unwanted births of girls, and ensure higher survival among those girls who are born.4.4Our exploratory analysis and selection of possible drivers of gender bias in mortality were based on two previous studies. Using data from LMICs in the 1980s, Tabutin and WillemsRegarding the education indicator, the direction of the association agrees with the literature. Results from Sub‐Saharan Africa and South Asia indicate that as maternal education increases, so does the male‐to‐female mortality ratio.Another indicator that might reflect women's position in society is the mean age at first marriage. In our analyses, we found that countries with an older average age at marriage may show less evidence of gender bias against girls in mortality. A correlation in the same direction had been reported previously, by Tabutin and Willems.Our finding of higher‐than‐expected mortality residuals may be interpreted as representing either neglect of girls, or improved care for boys. The correlation with gender‐specific care‐seeking suggests that higher rates for boys account, at least in part, for the observed mortality differences. These findings are also corroborated by our previous analysis of gender bias in care‐seeking practices in 60 DHS,In our sensitivity analyses, we calculated residuals using the equations proposed in previous studies for estimating sex differences in under‐five mortality.5In conclusion, our results confirm the importance of reporting on child mortality separately by sex and contribute to the existing literature by updating previous research on the association of mortality sex ratios and contextual factors. Contrary to our original set of hypotheses, national characteristics were not correlated with mortality residuals, except for higher care‐seeking for boys than for girls.Further research is needed to refine the analyses of explanatory factors for gender‐specific mortality.Supplementary MaterialClick here for additional data file.


With the dramatic increase of electron accumulation at the LaTiO3/SrTiO3 surface, providing a substantial surge of work function mismatch across the FeSe/oxide interface, the charge transfer and the superconducting gap in the monolayer FeSe are found to remain markedly robust. This unexpected finding indicate the existence of an intrinsically anchored “magic” doping within the monolayer FeSe systems.The enhanced superconductivity in monolayer FeSe on titanates opens a fascinating pathway toward the rational design of high‐temperature superconductors. Utilizing the state‐of‐the‐art oxide plus chalcogenide molecular beam epitaxy systems  3/SrTiO3 heterostructures with varied LaTiO3 thicknesses are synthesized by molecular beam epitaxy in‐situ connected to a synchrotron angle‐resolved photoemission spectroscope. The electron accumulation at the LaTiO3/SrTiO3 surface provides a substantial surge of work‐function mismatch across the FeSe/oxide interface, but the charge transfer and superconducting gap of FeSe remain remarkably robust, indicating an intrinsically anchored “magic” doping in FeSe.Monolayer FeSe/LaTiO TC) has been a central theme of material science research. A remarkable triumph is the monolayer FeSe grown on SrTiO3 , in which superconductivity is significantly enhanced compared to its bulk form. Experimental evidence so far suggests that the source of elevated TC is twofold: extra electron doping and interfacial mode coupling. The role of interfacial coupling effect has been extensively discussed in the literature.The quest for raising superconducting transition temperature TC has beeTC are obtained. Comparing these phase diagrams, two important pieces of information can be drawn. First, there exists a superconductor–insulator transition in a higher doping regime. Remarkably, transport measurements with Li intercalation exhibit apparent phase‐separation features across this transition, indicative of a first‐order phase transition instead of a continuous one. Second, a sharp discreteness of possible TC’s is found in the continuous tuning of Li doping, and the discreteness is smoothed with additional disorders, such as replacing Fe with Cu, S with Se, or increasing the size of dopant atoms . Although the spatially average carrier concentration is fixed by such doping method, in the presence of disorder, the carrier density distribution is often inhomogeneous. These observations call for a doping method for FeSe without the introduction of impurity dopants.To study the doping effect, researchers have employed alkaline metal  atom adsorption for bulk and multilayer FeSe. Due to the low ionization energy, alkali metal dosing or intercalation acts as a charge injector. Doping level can be tuned and phase diagrams of  Interestingly, the majority of reported high‐quality monolayer FeSe films grown on different types of perovskite titanate substrates, including STO(100), STO(110), and BaTiO3 with varied dielectric and work function properties, exhibit similar levels of doping (≈ 0.10–0.12 electrons per Fe atom). For increasing the doping ability of the substrate, the LaTiO3 (LTO)/STO heterostructure is an excellent candidate. LTO provides Ti3+ and forms a 2D electron gas (2DEG) accumulated at the surface of the LTO/STO heterostructure, indicating a lowered surface work function. When growing 1UC FeSe on top of LTO/STO, we would be able to provide an additional chemical potential difference across the interface for charge transfer to FeSe from LTO/STO, while maintaining other properties similar to 1UC FeSe/STO without introducing additional disorders due to the structural similarity between STO and LTO. Different from testing different perovskite substrates for FeSe arbitrarily, we can precisely control the thickness for LTO and thus provide the essential systematics. The in situ synchrotron angle‐resolved photoemission spectroscope (ARPES) can unambiguously determine the doping of FeSe by Fermi surface volume. Avoiding the use of Li or other alkaline atom adsorption, we can rule out any possibility of Li ordering. Importantly, the insertion of LTO systematically controls the interfacial work function difference for charge transfer, which is thermodynamically distinct from alkaline metal dosing or intercalation, where the number of electrons injected is proportional to the number of adsorption atom number.Monolayer FeSe grown on STO substrate is doped by interfacial charge transfer.19 Intin situ connected molecular beam epitaxy (MBE) chambers, then examine the low‐temperature electronic structure of the grown films byin situ ARPES in Stanford synchrotron radiation lightsource (SSRL). By varying LTO thickness, we find that the itinerant electron density at the surface of the LTO/STO heterostructure surges to more than 4 × 1014 cm−2, but surprisingly neither the doping nor the superconducting gap of 1UC FeSe film grown on it exhibit noticeable changes. Our results show that the superconductivity in 1UC FeSe thin films is robust and accompanied with an anchored “magic” doping level.In this work, we systematically synthesize 1UC FeSe films on LTO/STO heterostructures in two separate but in situ reflective high energy electron diffraction (RHEED). The STO buffer layer is grown using a shuttered approach for deposition of different elements. To grow LTO, we use a shuttered approach with on‐the‐fly adjustment of the shutter times layer‐by‐layer to maximize the RHEED intensity oscillations. We then transfer the LTO films in situ to a separate chalcogenide MBE chamber for the growth of 1UC FeSe. After vacuum post‐annealing, the samples are transferred in situ to the ARPES chamber at SSRL beamline 5‐2 for measurement. We control the annealing conditions identical for different samples to avoid annealing‐related variation. More details of growth and measurement conditions can be found in Supporting Information.We grow LTO films on STO substrates after the growth of STO buffer layers in a shutter‐controlled oxide MBE chamber, monitored by elements.25 To FigureΓ are ≈75 meV below Fermi level, and the bottom of electron bands at M is about 55 meV below Fermi level  photons until saturation, yet the electrons measured in LTO/STO exceed that of STO substrate by far even before such exposure to high‐energy photons, as shown in Supporting Information.To probe this artificial structure systematically, we measure 1UC FeSe grown on LTO films with different thickness, as shown in Figure 29 TheFigure xy, dyz, and dxz bands in the ARPES Fermi surface maps . Electron density quickly increases as the LTO film thickness changes from 0UC (bare STO) to 3UC, and reaches a plateau of ≈5 × 1014 cm−2 for 3UC and thicker LTO films. The saturation behavior is consistent with numerical simulation in Supporting Information. Electron density observed from the surface‐sensitive ARPES for thinner LTO films are lower, due to the electron redistribution between LTO and the STO layers. LTO films have effectively lower work functions, thus certain amount of itinerant electrons will be transferred to the STO layers. When LTO films are thicker, the interface between LTO and STO, where the charge transfer occurs, becomes deeper and less influential to the surface, resulting in an increased and saturated observable electron density. Based on the simulation in the Supporting Information, with the dense electron accumulation for LTO thicker than 3UC, the surface work function of the LTO/STO is lowered by ≈ 0.7 V.We summarize our results in 14 and 1.58 × 1014 cm−2, and the gap is mostly between 12 to 16 meV.In sharp contrast, the electron density as measured by ARPES Fermi surface maps and superconducting gap at low temperature for 1UC FeSe/LTO/STO films remain nearly unchanged with different LTO thickness, as plotted in Figure  Yet, this requires a blockage of electron tunneling between FeSe and the oxide substrate so that the work function across the interface does not need to be balanced. This is highly unlikely since it contradicts direct experimental evidence of charge transfer. As electrons move across the interface between FeSe and the titanate substrate, an energy equilibrium state would be established by the redistribution of electrons. Here, we increase the electron density in titanate substrates to ≈ 5 × 1014 cm−2, much larger than the typical electron density of monolayer FeSe/STO, not only effectively creating metal–metal contact, but also greatly lowered the effective work function of the substrate surface. Note that the nature of metal‐metal contact is insensitive to interface details such as terminations. After FeSe is grown on LTO/STO, for balancing additional work function difference across the interface, FeSe electron density would be expected to be much higher than the case on STO substrates (see more details in Supporting Information). Therefore, the ARPES measured unchanged doping of 1UC FeSe/LTO/STO points to some unusual intrinsic properties of FeSe.As the doping level is anchored for 1UC FeSe despite large changes in the substrate, an immediate implication could be that the doping is from the monolayer FeSe film itself alone, such as Se vacancies.33 Yet where discrete TC changes are observed as Li is continuously intercalated , further doping brings the system into an insulator with marked discreteness in transport measurements. The superconductor–insulator phase transition is also observed in K dosing experiments on multilayer FeSe thin films. The doping for maximal TC (≈ 45 K) is ≈ 0.11 electrons/Fe atom, similar to the case of 1UC FeSe on STO or LTO. Above this doping, the system gradually transitions into an insulating phase. The major difference between the Li and K experiments is the level of discreetness. The K experiment seems to be a smoothed version of the Li experiment. In our work, we find an unusually anchored doping level despite strong interface electron accumulation as a “clean” doping channel, since we do not introduce extra disorder by ad‐atoms or vacancies. Moreover, as a method of varying interfacial work function difference rather than direct injection of electrons (as in Li or K experiments), by LTO insertion we have not observed obvious signatures of the insulating phase nor phase separation. These results are summarized in Figure Similar phenomenon of robust superconductivity is also seen in the Li‐intercalated FeSe thin flake experiment,18 whe However, in the FeSe/LTO/STO system, the extra work function difference, which would facilitate higher electron transfer at the interface in a trivial case, need to exceed a critical potential barrier originated from the theoretical first‐order phase transition to transit into the insulating phase. Our observation of an anchored doping and absence of the insulating features suggests such critical potential barrier is still higher than the increased work function difference built by LTO insertion. Even if small amount of insulating phase would exist and form phase separations due to finite temperature, only the ≈ 0.11 doping superconducting phase would be visible by ARPES, and the minor portion of insulating phase would be hard to discern by APRES due to the low intensity and the defuse nature of the spectra. This scenario might also explain why most reported high‐quality monolayer FeSe films grown on different types of perovskite titanate substrates “magically” exhibit similar ≈ 0.11 doping in ARPES, which coincidentally corresponds to the maximum TC found in doped multilayer systems. In the cases of K/Cs dosing or excess Se, additional disorders are introduced and the discreteness is smoothed, making the transitions more continuous and less first‐order‐like. This leads to a continuous change in Fermi surface volume and TC. Interestingly, the TC evolution with Na intercalation represents an intermediately smoothed case between Li and K.Our results of a “magic” anchored doping on 1UC FeSe despite large variation in substrate carrier density, combined with the studies listed above, show that the doping of FeSe is far from being fully understood. Below we propose a scenario that could possibly explain the unique phenomena of FeSe doping levels. In theory, there might exists a first‐order phase transition between a superconducting phase with a maximum possible doping of ≈ 0.11 and an insulating phase at a higher doping governed by a yet concealed order for FeSe. In real material, true first‐order phase transition may not exist with the presence of disorder, but by approaching the “clean” limit, first‐order‐like behaviors, such as phase separations, could be observed. Thus, electron injection higher than ≈ 0.11 by Li dosing to FeSe could have formed phase separations between the superconducting phase and the insulating phase.18 How Therefore, the largely unchanged superconducting gap of FeSe on LTO with different thicknesses suggests that the relevant interfacial coupling at FeSe/oxide interface are strongly selective for the phonon modes involved.Another aspect of our results is the largely invariant superconducting gap under great change of itinerant electron density in the substrate. For the interfacial electron–phonon coupling with phonon modes in directions parallel to the surface, dense itinerant 2DEG on LTO surface can provide strong screening effect. However, because the in‐plane motion of carriers in the substrate cannot screen the charge transfer induced electric field that is perpendicular to the interface, we expect the extra carriers in LTO cannot screen the long‐wavelength longitudinal optical phonon modes associated with ionic vibrations that are also perpendicular to the interface and modulating the interfacial electric field. It is precisely this type of phonon which is suggested to enhance the superconductivity in 1UC FeSe/STO system.39 Thein situ oxide and chalcogenide MBE systems that are directly coupled to the synchrotron ARPES, we have systematically studied the electronic structure 1UC FeSe on LTO/STO heterostructures. We find that the doping level and enhanced superconductivity of the monolayer FeSe is exceptionally robust in spite of substantial increase of electron density in the substrate. The indicated anchored “magic” doping level suggests a unique underlying material property, posing a challenging target for theoretical and computational materials science research.In conclusion, empowered by the The authors declare no conflict of interest.Supporting InformationClick here for additional data file.


Volcanic eruptions are one of the largest natural disturbances and are followed by the establishment of novel plant and animal communities in terrestrial ecosystems. However, the role of pre‐eruption vegetation in the establishment of arthropod communities after volcanic disturbances is currently unknown. Here, we asked whether the legacy of pre‐eruption vegetation mediates the community structure of ground‐dwelling arthropods after volcanic disturbances. The 2015 eruption in Kuchinoerabu‐jima Island, southwest Japan, caused two types of disturbances [a pyroclastic flow and a lahar ] in three types of forests . We hypothesized that pre‐eruption vegetation would influence the community structure of ground‐dwelling arthropods after the disturbance, and we expected that these effects from vegetation would be more prevalent for the less severe disturbances. The total abundance of ground‐dwelling arthropods decreased more in the lahar than the pyroclastic flow, and arthropod species composition showed a greater change after the lahar. These findings suggest that the lahar disturbance was more severe than the pyroclastic disturbance. Contrary to expectations, the difference in the arthropod species composition among the vegetation types was greatest after the lahar. After the pyroclastic flow, leaf litter remained to some degree with all the vegetation types. After the lahar disturbance, however, although the litter in the cedar forests remained, the litter disappeared completely from broad‐leaved and black pine forests. The disappearance of litter from these two forest types after the lahar may be responsible for the greater difference in arthropod species composition among the vegetation types. This study shows that the legacy effects of pre‐eruption vegetation on terrestrial arthropod communities after volcanic disturbance were different depending on the type of disturbance. Focusing on the role of pre‐eruption biotic factors would contribute to a better understanding of the recovery processes of terrestrial ecosystems after large natural disturbances. Our paper found that the legacy of pre‐eruption vegetation influenced the community structure of ground‐dwelling arthropods after volcanic disturbances. Moreover, counterintuitively, these legacy effects of vegetation were more evident for the more severe disturbances. This figure shows how biological legacy of forests remains after receiving the volcanic disturbances. For this purpose, we conducted a field survey to monitor arthropod communities at sites with different combinations of three disturbance conditions, namely undisturbed, the pyroclastic flow, and the lahar, and three vegetation types: evergreen broad‐leaved forest, black pine forest, and cedar forest. Since the vegetation structure plays a critical role in shaping the associated terrestrial arthropod communities  Does the community structure of ground‐dwelling arthropods differ, after a volcanic disturbance, depending on pre‐eruption vegetation types? (2) If so, does the prevalence of legacy effects relating to pre‐eruption vegetation types differ between the two types of volcanic disturbances ? (3) What factors are responsible for and mediate the legacy effects of pre‐eruption vegetation on arthropod communities?22.1This study was conducted in late October both 2016 and 2017 at the Mukaehama and Maeda areas, in a cove of mid‐west Kuchinoerabu‐jima Island  forest, and cedar (Cryptomeria japonica) forest . Pictures of forests receiving the volcanic disturbances are given in Figure The vegetation of the Mukaehama and Maeda areas consisted primarily of three types of forest stands: evergreen broad‐leaved forest mainly consisting of 2.2To examine whether the community structures of ground‐dwelling arthropods differed depending on the conditions of the volcanic disturbance and the vegetation type, we surveyed ground‐dwelling arthropod communities in the Mukaehama area after the volcanic disturbance. By using pitfall traps, we monitored arthropod communities at nine types of sampling sites, which were the full combinations of the three conditions of volcanic disturbance  and the three vegetation types . We arbitrarily selected five points in each combination as sampling sites, comprising 45 points in total Figure . The minAlong with the biotic monitoring, we also assessed two environmental parameters: relative light intensity and deposited litter depth. We measured the light intensity at each sampling site at 10–11 a.m. in 2017 using illuminant meters . We simultaneously measured the light intensity in an open area next to each sampling site as a control and calculated the relative light intensity (%) as (light intensity at a sampling site / control light intensity) × 100. The depth of the litterfall was measured by inserting a measuring device into the litter layer.2.3J’. The J’ value ranged from 0 to 1. The higher the J’ value is, the higher the evenness in the community. For each community property, we constructed a mixed model containing disturbance condition  and vegetation type  and their interaction as explanatory variables. Site identity and year were included as random effects. We assumed a negative binomial error distribution for total abundance and normal error distributions in relation to species richness and evenness. When assuming a normal error distribution, the data were ln(x)‐transformed to meet the assumption of normality and homoscedasticity when necessary. The significance of each term was tested using type III likelihood ratio tests for the negative binomial model and type III F tests with Kenward–Roger degrees of freedom for the normal models, followed by Tukey tests among different disturbance conditions and different vegetation types within each disturbance condition. Note that rarefied richness and evenness may be elevated in the disturbed sites only because the abundant taxa in the undisturbed sites were decreased by disturbances. In addition, the presence of one colony of colonial species  could cause the capture of hundreds or thousands of individuals, perhaps leading to distorted results. Therefore, we performed additional analyses for the above community properties in which Formicidae, which was the most abundant family (see Results), was omitted from the data to confirm whether this family compromised the results . The negative binomial and normal models were constructed using the packages “glmmTMB” version 1.0.2.1 ‐transformed before calculating the Bray–Curtis dissimilarity. To obtain biplots of taxa and sites from the NMDS, we overlaid vectors representing correlations between the counts of each family at each site and the site scores along the NMDS ordination axes ‐transformed abundance of each feeding guild as a response variable and disturbance condition, vegetation type, feeding guild, and their interactions were explanatory variables. Year and site identity were included as random effects. A normal error distribution was chosen because any generalized methods  failed to fit our data well. When the disturbance × vegetation × guild interaction was significant (as examined by F test with Kenward–Roger degrees of freedom), we judged that the composition of the feeding guilds differed among vegetation types and that these differences depended on disturbance condition. Additionally, we constructed similar models for each disturbance condition separately and then tested the significance of the vegetation × guild interaction by F tests to examine if the composition of feeding guilds differed among vegetation types for different disturbance conditions.To visualize whether and how disturbance conditions and vegetation types altered the species compositions of ground‐dwelling arthropods, we performed nonmetric multidimensional scaling (NMDS) with Bray–Curtis dissimilarity. The data were log.The lahar decreased the total abundances of ground‐dwelling arthropod communities more than did the pyroclastic flow Figure . The totJ’) of ground‐dwelling arthropods were not diminished but were even increased slightly by the volcanic disturbances, although species density  was slightly lowered at the lahar sites . The ground‐dwelling arthropod communities of undisturbed sites and the sites in the pyroclastic flow and the lahar were located along NMDS axis 1 from left to right in this order. The vegetation type also influenced the species composition , and its effects depended on the conditions of the volcanic disturbance . The species composition at undisturbed sites was located at different positions in the multivariate species space among different vegetation types, while the compositions at the sites in the pyroclastic flow that had different vegetation types were not clearly separated from each other compared to that at undisturbed sites . Pairwise comparison revealed that there were no significant differences in the residuals among vegetation types at the sites in the pyroclastic flow but that the cedar forest sites in the lahar were significantly different relative to the broad‐leaved and pine forest sites in the lahar  decreased in their abundance Figure , while tF16,344.0 = 8.63, p < .001). The abundance rank of each guild was omnivores, carnivores, detritivores, herbivores, and scavengers in general. However, detritivore abundance was high at the undisturbed cedar sites, suggesting the effects of vegetation type on the feeding guild composition within the undisturbed sites . In contrast with the undisturbed sites, within the sites in the pyroclastic flow, the distribution of feeding guilds no longer significantly differed among vegetation types . Furthermore, within the sites in the lahar, the statistically significant effect of vegetation type on feeding guild composition was also suggested, but F statistics suggested that the significance of the effect was weaker than that within the undisturbed sites . Specifically, detritivores, herbivores, and scavengers almost disappeared from the broad‐leaved and black pine forest sites, whereas they were still present at cedar forest sites  and litter depth . Relative light intensities at the sites in the pyroclastic flow and lahar were considerably higher than that at undisturbed sites , which depended on volcanic disturbance , the effects were not as obvious as the effects of disturbance , depending on disturbance condition  and Agrypnus miyamotoi (Elateridae), which are generalist carnivores and/or scavengers. In general, arthropods that initially colonize bare ground and become dominant are not primary consumers but rather secondary or higher order consumers  which increased in terms of their abundance along NMDS axis 1 Figures  and S6. In this study, the arthropod species compositions at the sites in the pyroclastic flow were plotted between those of the undisturbed sites and the sites in the lahar on the NMDS ordination Figure . The 15 4.2Our study clearly showed that the legacy of vegetation types influenced the species compositions of ground‐dwelling arthropods after volcanic disturbances and that these legacy effects were more prevalent at the sites in the lahar compared to the pyroclastic flow Figure . The legThere are at least two possible reasons why cedar forests retained leaf litter even at the sites affected by the lahar. First, leaves that fell from canopies after the disturbance may have generated the litter deposits. At the sites in the lahar, trees from all the forest types died while standing, and while leaf litter could fall from dead standing trees in any type of forest, cedars are known to produce more litter from their canopies compared to broad‐leaved trees and black pines Yoshida, . The chaUnlike the lahar sites, the species compositions of arthropod communities at the pyroclastic flow sites were similar among the different types of vegetation Figure . This su4.3Volcanic disturbances are one of the largest natural disturbances, and their consequences for communities and ecosystems are diverse and complex. Moreover, since volcanic disturbances are relatively rare events, it is difficult to make generalities about whether and how the ecosystems receiving volcanic disturbances recover their predisturbance states or shift to alternative states. In this context, the effects of biological legacies on disturbed communities and ecosystems have been suggested to be key to understanding ecosystem resilience against natural disturbances, because biological legacies could act as “memories” of predisturbance conditions  the legacy of pre‐eruption vegetation certainly influenced the community structure of ground‐dwelling arthropods and (2) the type of volcanic disturbance differently altered the legacy effects of pre‐eruption vegetation types on the arthropod communities. Previous studies examining the effects of volcanic eruptions on terrestrial arthropods rarely considered the biological legacies of pre‐eruption biotic factors. Moreover, there are few studies examining the community‐level effects of volcanic eruptions on arthropods. In this context, our study emphasizes the need for considering community properties and the legacy of vegetation structures for a more comprehensive understanding of arthropod responses to volcanic eruptions. Given the importance of ground‐dwelling arthropods for ecosystem function Lal, , these sWe declare no conflict of interest.Kyohei Iida: Conceptualization (lead); Data curation (lead); Formal analysis ; Investigation (lead); Methodology ; Visualization ; Writing‐original draft . Daisuke Hayasaka: Conceptualization (supporting); Funding acquisition (lead); Project administration (lead); Resources (lead); Supervision (lead); Validation ; Writing‐original draft (supporting). Yuya Suzuki: Data curation (supporting); Investigation (supporting); Writing‐review & editing . Taizo Uchida: Conceptualization (supporting); Writing‐review & editing . Takuo Sawahata: Conceptualization (supporting); Funding acquisition (supporting); Project administration ; Resources (supporting); Validation ; Writing‐review & editing . Koya Hashimoto: Conceptualization (supporting); Formal analysis ; Methodology ; Visualization ; Writing‐original draft .Appendix S1Click here for additional data file.