Artículos de revistas sobre el tema "Dunbar's model"

Abstract With attention to representations of the land and labor in the postslavery agricultural South of the nadir—a period when American apartheid was at its most violent—this essay uses Paul Laurence Dunbar’s plantation poems and W. E. B. Du Bois’s cotton novel, The Quest of the Silver Fleece (1911), to explore counternarratives of black subjecthood. Agriculture’s focus on productive collaborations with the nonhuman, on cycles of decay and rebirth, and on the potential for self-determination provides a generative vocabulary for conceptualizing nadir-era experiences of the human. Under this model, literature provides a venue wherein the legacies of the plantation might be imaginatively transposed from a Jim Crow necropolitics of violent constraint and dispossession into vectors of agropolitical possibility. To that end, the essay uses Dunbar and Du Bois to propose potentially radical processes of black subject formation wherein physical and imaginative instances of reclamation give rise to fresh mergers of epistemic and embodied selfhood.

Background/aims In the conduct of phase I trials, the limited use of innovative model-based designs in practice has led to an introduction of a class of “model-assisted” designs with the aim of effectively balancing the trade-off between design simplicity and performance. Prior to the recent surge of these designs, methods that allocated patients to doses based on isotonic toxicity probability estimates were proposed. Like model-assisted methods, isotonic designs allow investigators to avoid difficulties associated with pre-trial parametric specifications of model-based designs. The aim of this work is to take a fresh look at an isotonic design in light of the current landscape of model-assisted methods. Methods The isotonic phase I method of Conaway, Dunbar, and Peddada was proposed in 2004 and has been regarded primarily as a design for dose-finding in drug combinations. It has largely been overlooked in the single-agent setting. Given its strong simulation performance in application to more complex dose-finding problems, such as drug combinations and patient heterogeneity, as well as the recent development of user-friendly software to accompany the method, we take a fresh look at this design and compare it to a current model-assisted method. We generated operating characteristics of the Conaway–Dunbar–Peddada method using a new web application developed for simulating and implementing the design and compared it to the recently proposed Keyboard design that is based on toxicity probability intervals. Results The Conaway–Dunbar–Peddada method has better performance in terms of accuracy of dose recommendation and safety in patient allocation in 17 of 20 scenarios considered. The Conaway–Dunbar–Peddada method also allocated fewer patients to doses above the maximum tolerated dose than the Keyboard method in many of scenarios studied. Overall, the performance of the Conaway–Dunbar–Peddada method is strong when compared to the Keyboard method, making it a viable simple alternative to the model-assisted methods developed in recent years. Conclusion The Conaway–Dunbar–Peddada method does not rely on the specification and fitting of a parametric model for the entire dose-toxicity curve to estimate toxicity probabilities as other model-based designs do. It relies on a similar set of pre-trial specifications to toxicity probability interval-based methods, yet unlike model-assisted methods, it is able to borrow information across all dose levels, increasing its efficiency. We hope this concise study of the Conaway–Dunbar–Peddada method, and the availability of user-friendly software, will augment its use in practice.

We address the connection between conceptual knowledge and cognitive control using a neural network model. This model extends a widely held theory of cognitive control [Cohen, J. D., Dunbar, K., & McClelland, J. L. On the control of automatic processes: A parallel distributed processing model of the Stroop effect. Psychological Review, 97, 332-361, 1990] so that it can explain new empirical findings. Leveraging other computational modeling work, we hypothesize that representations used for task control are recruited from preexisting representations for categories, such as the concept of color relevant to the Stroop task we model here. This hypothesis allows the model to account for otherwise puzzling fMRI results, such as increased activity in brain regions processing to-be-ignored information. In addition, biologically motivated changes in the model's pattern of connectivity show how global competition can arise when inhibition is strictly local, as it seems to be in the cortex. We also discuss the potential for this theory to unify models of task control with other forms of attention.

Extensive empirical evidence suggests that there is a maximal number of people with whom an individual can maintain stable social relationships (the Dunbar number). We argue that this arises as a consequence of a natural phase transition in the dynamic self-organization amongNindividuals within a social system. We present the calculated size dependence of the scaling properties of complex social network models to argue that this collective behavior is an enhanced form of collective intelligence. Direct calculation establishes that the complexity of social networks as measured by their scaling behavior is nonmonotonic, peaking around 150, thereby providing a theoretical basis for the value of the Dunbar number. Thus, we establish a theory-based bridge spanning the gap between sociology and psychology.

Electrical submersible pump (ESP) operation is compromised by free gas, resulting in premature pump failure and production losses in new wells. It is essential to detect the onset of abnormal operations. We develop a model that predicts abnormal ESP operation when the free gas level increases in the pump. The model compares operation parameters with the parameters of normal operating ranges; it shuts down the ESP when necessary. We used a Schlumberger PIPESIM software (version 2017.01) to perform nodal analysis technique; we tested the model using the other multiphase correlation model and field case studies (where the gas problem in ESP was reported). We employ a homogenous model to calculate the differential pump pressures at various gas volume fractions. Nodal analysis of the intake and discharge point predicted the commencement of abnormal ESP conditions and the associated parameters (critical gas fraction, minimum operating pump intake pressure, and pump discharge pressure). The model results were similar to other surging correlation models (e.g., Romero, Dunbar, Turpin, Cirilo, and Zhou models); they were also identical to field case studies. We identify three performance stability phases when an ESP is exposed to free gas. These are the normal and abnormal operating ranges, as well as the ESP shutdown condition. Modeling permits careful monitoring of ESP operations that can be compromised by free gas.

Zusammenfassung. In diesem Überblick werden Ergebnisse zum komplexen Problemlösen dargestellt, die anhand von linearen Systemen gewonnen wurden. Zuerst wird definiert, was lineare Systeme sind. Die Ergebnisse werden getrennt nach Personen- oder Aufgabenmerkmalen aufgeführt. Als Personenmerkmale wurden die Variablen Motivation, Intelligenz und Strategien untersucht, Aufgabenmerkmale waren Semantische Einkleidung, Zielspezifität, Hypothesentesten und Wissenserwerb. Zur Integration der Ergebnisse in ein theoretisches Modell wird auf das Zwei-Räume-Modell von Klahr und Dunbar (1988) verwiesen.

Phonetic category acquisition involves a distributional learning mechanism (Maye, Werker, and Gerken 2002). Some researchers suggest that phonetic category acquisition is only the first step in a two-step model of phonological acquisition by modelling these two steps separately (Guenther and Gjaja, 1996; Boersma, Escudero, and Hayes, 2003; Peperkamp, Pettinato, and Dupoux 2003; Peperkamp, Calvez, Nadal, and Dupoux 2006), while others have argued for a one-step model (Dillon, Dunbar, and Idsardi 2013). This experimental study maps the learning trajectory of three groups of adult learners: (1) a group exposed to a bimodal frequency distribution where both halves of the bimodal distribution occur in complementary environments (Bimodal-Comp group), (2) a group exposed to a bimodal frequency distribution where both halves of the bimodal distribution occur in non-complementary environments (Bimodal-NonComp group), and (3) a group exposed to a monomodal frequency distribution (Monomodal group). This study finds support for a one-step model of phoneme acquisition, with the Bimodal-Comp group having lower sensitivities to critical stimuli than even the Monomodal group at all three exposure times tested.

The modelling of financial markets presents a problem which is both theoretically challenging and practically important. The theoretical aspects concern the issue of market efficiency which may even have political implications (Cuthbertson, 1996), whilst the practical side of the problem has clear relevance to portfolio management (Elton and Gruber, 1995) and derivative pricing (Hull, 1997). Up till now all market models contain "smart money" traders and "noise" traders whose joint activity constitutes the market (De Long et al., 1990; Bak et al., 1997). On a short time scale this traditional separation does not seem to be realistic, and is hardly acceptable since all high-frequency market participants are professional traders and cannot be separated into "smart" and "noise". In this paper we present a "microscopic" model with homogenuous quasi-rational behaviour of traders, aiming to describe short time market behaviour. To construct the model we use an analogy between "screening" in quantum electrodynamics and an equilibration process in a market with temporal mispricing (Ilinski, 1997; Dunbar, 1998). As a result, we obtain the time-dependent distribution function of the returns which is in quantitative agreement with real market data and obeys the anomalous scaling relations recently reported for both high-frequency exchange rates (Ghashghaie et al., 1996, S&P500 (Mantegna and Stanley, 1994) and other stock market indices (Bouchaud and Sornette, 1994; Matacz, 1997).

Shifts in chaplain requests from patients and families and lack of engagement by staff in now traditional support forms in the COVID-19 context suggest that new insights and resourcing are needed. This exploratory translational study suggests that the evolutionary psychology of R. I. M. Dunbar and the social neuroscience of J. T. Cacioppo, his collaborators, and successors and their concerns for human loneliness have potential for use in development of effective healthcare chaplaincy practice in the COVID-19 context.

ABSTRACT Understanding patterns of biodiversity in microbial communities is severely constrained by the difficulty of adequately sampling these complex systems. We illustrate the problem with empirical data from small surveys (200-member 16S rRNA gene clone libraries) of four bacterial soil communities from two locations in Arizona. Among the four surveys, nearly 500 species-level groups (Dunbar et al., Appl. Environ. Microbiol. 65 : 662-1669, 1999 ) and 21 bacterial divisions were documented, including four new candidate divisions provisionally designated SC1, SC2, SC3, and SC4. We devised a simple approach to constructing theoretical null models of bacterial species abundance. These null models provide, for the first time, detailed descriptions of soil bacterial community structure that can be used to guide experimental design. Models based on a lognormal distribution were consistent with the observed sizes of the four communities and the richness of the clone surveys. Predictions from the models showed that the species richness of small surveys from complex communities is reproducible, whereas the species composition is not. By using the models, we can now estimate the required survey scale to document specified fractions of community diversity. For example, documentation of half the species in each model community would require surveys of 16,284 to 44,000 individuals. However, quantitative comparisons of half the species in two communities would require surveys at least 10-fold larger for each community.

Dog bites are a public health concern that also implicates animal welfare, with negative outcomes such as rehoming or euthanasia for the animals responsible. Previous research has shown that the severity of dog-bite injuries reflects multiple factors, including the degree of inhibition exhibited by dogs and how people behave towards dogs. This study utilizes an objective dog bite injury assessment tool: The Dunbar aggression scale. Trained officers employed by The City of Calgary systematically use the Dunbar scale whenever investigating dog-bite complaints. We analyzed The City of Calgary’s administrative data on confirmed dog-bite injuries in people, 2012–2017, with a multivariable generalized ordered logistic regression model. Severe dog-bite injuries occurred more frequently in the family home than in any other setting. Young children, youths and older adults were at higher risk of more serious bites than adults. There has been a decreasing trend in the probability of a high or medium severity bite, and an increasing trend in the probability of a low severity bite since 2012. These results indicate that greater public awareness regarding dog-bite injuries is needed. Consideration should be given to campaigns targeted towards different demographics, including older adults, to provide an understanding of dog behaviour and to emphasize the need to supervise children closely in the presence of all dogs at all times, including family dogs in the home environment. Given that dog-bite injuries are not just a public health issue, but also an animal welfare issue, we endorse One Health responses in educational campaigns, policy development, and professional practice.

A History of the Small Arms Made by the Sterling Armament Company: Excellence in Adversity Reviewed by: Jack Shanley Peter Laidler, James Edmiston & David Howroyd. Barnsley: Pen & Sword, 2020. ISBN 978-15-26773-30-2. xv + 352 pp., 32 col. illus., 350 b. & w. illus. £40. Winchester Model 1895: Last of the Classic Lever Actions Reviewed by: Danny Michael Rob Kassab & Brad Dunbar. Boca Raton: Buffalo Cove Publishing, 2019. ISBN 978-0-578-46655-2. 432 pp., numerous col. illus. $89.99. Firearms of the Texas Rangers: From the Frontier Era to the Modern Age Reviewed by: Patrick Senft Doug Dukes. Denton: University of North Texas Press, 2020. ISBN 978-1-574-41810-1. 640 pp., 182 b. & w. illus. $45.

Several models of the evolution of religion claim that ritual creates “religion” and gives it a positive evolutionary role. Robert Bellah suggests that the evolutionary roots of ritual lay in the play of animals. For Homo sapiens, Bellah argues, rituals generate a world of experience different from the world of everyday life, and that different world of experience is the foundation of later religious developments. Robin Dunbar points to trance dancing as the original religious behavior. Trance dancing both alters ordinary consciousness and generates trance experiences that will give rise to religious concepts and also, through the production of endorphins, bonds people into tight-knit social groups whose social bonding gives them a survival advantage. The role of ritual in social bonding has been well established through the research on the production of endorphins by synchronized activity and the role of endorphins in social bonding. The role of ritual in generating religious experience has been much less developed. Drawing on the extensive research on the ways in which bodily activity can impact and transform our sensory and cognitive processes, and the ways in which sensory and cognitive processes are neurologically connected with somatic processes, this article will propose one neuropsychological model of how ritual activity might give rise to religion. Starting from bodily activity means that here religion will be understood more as a set of practices and less as a set of beliefs. Theological implications of this model will be discussed.

In this work we interpret the Einstein-Hilbert (EH) Lagrangian of gravitation as the first term of a low-energy effective theory similar to those considered in the chiral Lagrangian approach to low-energy hadron physics or the electroweak chiral Lagragians describing the symmetry breaking sector of the Standard Model (SM). Starting from the one-loop computation of the elastic gravitongraviton scattering amplitude by Dunbar and Norridge, we unitarize the IR regularized partial waves by using the Inverse Amplitude Method (IAM). This method enlarges the regime of applicability of the perturbative results to higher energies of the order of the Plank scale MP and allows for the possibility of poles in the second Riemann which have the natural interpretation of dynamical resonances. In this work we look for these possible resonances for the ++++ and −−−− helicity channels and the J = 0, 2 and 4 partial waves.

Nations in the bubble of social reality: language and all that In the last century and a half scholars from different disciplines began to distinguish between material reality (the universe), the biosphere, and social reality (the semiosphere), as three important heuristic categories. In the latter half of the 20th century, the philosophers John L. Austin and John Searle proposed that language and its use enable humans to generate social reality. They also analyzed the mechanisms of the process. From another perspective, the evolutionary anthropologist Robin Dunbar offered an explanation of how language was selected in the process of human evolution, and argued that its primary function is group-building, that is, the generation of social cohesion. Drawing on these insights, the article proposes that the dilemma of whether nations exist objectively or are subjective entities can be resolved by analyzing this problem in the light of Searle’s distinction between ontological objectivity / subjectivity and epistemic objectivity / subjectivity. Narody w koronie rzeczywistości społecznej widziane z perspektywy językaOd półtora stulecia badacze z zakresu różnych dyscyplin zaczęli wyraźnie rozróżniać pomiędzy rzeczywistością materialną (tj. wszechświatem, ogółem bytów materialnych), biosferą oraz rzeczywistością społeczną (semiosferą), jako powiązanymi ze sobą trzema kategoriami analizy heurystycznej. W drugiej połowie XX stulecia filozofowie języka John L. Austin i John Searle dali tezę, iż to język oraz jego użycie pozwala ludziom generować rzeczywistość społeczną. Obydwaj również badali mechanizmy rządzące tym procesem generacji. Z kolei psycholog ewolucyjny Robin Dunbar przedstawił model wyjaśniający, jak język (tzn. biologiczna zdolność językowa) został wyselekcjonowany w procesie ewolucji. Na tej podstawie postawił on tezę, iż prymarną funkcją języka jest umożliwianie budowania grup ludzkich, czyli innymi słowy, generowanie potrzebnej ku temu spójności społecznej. Korzystając z powyżej wymienionych ustaleń, artykuł proponuje nowe podejście do szeroko dyskutowanej kwestii czy narody istnieją obiektywnie lub są subiektywnymi bytami, analizując to zagadnienie w świetle zaproponowanego przez J. Searle’a rozróżnienia pomiędzy ontyczną obiektywnością/subiektywnością a epistemiczną obiektywnością/subiektywnością.

Während die Akzeptanz und positive Wirkung videofallbasierten Lernens empirisch belegt ist (Schrader et al. 2010), ist die Frage, unter welchen Bedingungen wissenschaftlich abgesicherte Videofallarbeitskonzepte in die Aus- und Weiterbildungspraxis von (angehenden) Lehrpersonen integriert werden können, wenig untersucht (Digel und Hetfleisch 2013). In der vorliegenden Studie werden aus authentischen Experimentierphasen von Schülerinnen und Schülern in Kleingruppen im naturwissenschaftlichen Unterricht interaktive Videovignetten erstellt, die in Lehrveranstaltungen im Master eingesetzt sowie zur individuellen Nutzung auf einer Lehr-Lernplattform zur Verfügung gestellt werden. Die Studierenden beobachten, beschreiben und analysieren die videografierten Situationen im Event-Sampling und entwickeln Handlungsalternativen. Sie nutzen hierbei ein Kategoriensystem, das auf dem SDDS-Modell basiert (Klahr und Dunbar 1988; Klahr 2000). Die Analysen der Studierenden werden mit Expertenratings verglichen. Die Ergebnisse zeigen, dass auf Basis dieser videobasierten Lerngelegenheiten die Diagnosekompetenz von Lehramtsstudierenden der naturwissenschaftlichen Fächer in Bezug auf die experimentellen Problemlösefähigkeiten von Schülerinnen und Schülern bereits in der universitären Ausbildungsphase angebahnt werden kann. Die einzelfallgestützte, qualitative Auswertung der Lernprozessanalysen zeigt eine zunehmende Reflexionsbreite, die jedoch noch nicht durchgängig am SDDS-Modell bzw. Kategoriensystem begründet wird (Reflexionstiefe).

Social business moves beyond linear, process-driven organizations to create new, dynamic, networked businesses that focus on customer value. Enterprise network (EN) is used to support social business by maximizing current and future opportunities and facilitate network-enabled processes, which can lead to value co-creation. EN is a multi-level hypergraph model with enterprises, employees, products and other related entities. In this paper the authors refine the EN model and present the foundation of EN to support social businesses. Then they introduce a case study on China automobile supply network (CASN). For the similarity with social networks, they verify power-law and small world theories in EN with statistical results on this data set. These theories are fitful in EN, but some new characteristics exist. The structure of EN consists of star-shaped clusters and the authors extract ego networks taking suppliers and manufacturers as the ego respectively. With the structure and distribution features of EN, they present the enterprise business similarity analysis method based on common-neighbors. And they also introduce the tentative work to detect Dunbar circles in EN. To analyze the data in a more intuitional and effective way, the authors use some data visualization tools to process the data in EN.

One key issue in bilingualism is how bilinguals control production, particularly to produce words in the less dominant language. Language switching is one method to investigate control processes. Language switching has been much studied in comprehension, e.g., in lexical decision task, but less so in production. Here we first present a study of language switching in Italian–English adult bilinguals in a naming task for visually presented words. We demonstrate an asymmetric pattern of time costs to switch language, where participants incurred a greater time cost to switch into naming in their dominant language (Italian). In addition, costs were greater where the stimuli were interlingual cognates or homographs than words existing in only one language, implicating lexical competition as a source of the cost. To clarify the operation of control processes, we then present two connectionist models of bilingual naming, based on the previous models of Seidenberg and McClelland (1989), Cohen, Dunbar and McClelland (1990), Gilbert and Shallice (2002), and Karaminis and Thomas (2010). Crucially, both models acquired their differential language dominance via an experience-dependent learning process. The models embody different assumptions about the language control processes that produce the switch cost. We consider which processing assumptions are sufficient to explain asymmetric language switch costs and word class effects on language switching in individual word reading, as well as generating novel predictions for future testing.

Background Facing growing accountability pressures, Teacher Work Samples (TWSs) as a model of performance-based assessment is of growing significance in teacher education. Developed at Western Oregon University and widely adopted and adapted, proponents claim that the model is “real,” “natural,” “meaningful,” and “helpful” (G. R. Girod, 2002). Research Questions The study addresses three questions: (1) How do sample raters understand their responsibilities? (2) What are the underlying interactive rules and strategies used by raters to achieve their aims, and how are they employed? (3) What issues or concerns should teacher educators interested in using TWS methods address as they seek to demonstrate candidate quality and program value? Research Design Conversation analysis, ethnomethodology. Data Collection and Analysis Ten TWS scoring conversations conducted by four teams were recorded and analyzed to identify interactive rules and strategies. Scoring teams were composed of one tenure-track elementary teacher education faculty member and one clinical teacher education faculty member. Excerpts from a TWS case judged marginal are presented and analyzed. Findings From the case, a set of interactive rules (tenure-track faculty speak first; the efficiency and equivalence rules; and scorers are prepared) and strategies (splitting the difference; rubric simplification; previewing scores; and rubric stretching) are identified, and implications of their use are discussed for assessment validity, fairness, content quality and coverage, meaningfulness, and cognitive complexity (R. L. Linn, E. L. Baker, & S. B. Dunbar, 1991). Conclusions This study raises a number of concerns about the expectations for and use of Teacher Work Samples and cautions about their use for high-stakes assessment.

Abstract The classical model of hematopoiesis states that differentiation proceeds from hematopoietic stem cells (HSC) to mature blood cells via specified multipotent and bipotent progenitors, such as the common myeloid progenitor (CMP), common lymphoid progenitor (CLP), erythrocyte-megakaryoctye progenitor and granulocyte-monocyte progenitor. However, recent studies question this assumption and suggest that these intermediates are neither required nor prevalent. As an example, analyses of binarized data from murine barcoding experiments (Perie et al, Cell Reports, 2014) raise the possibility that hematopoiesis progresses via a random loss of potentials rather than discrete steps. Additionally, Notta et al (Science, 2015) showed that oligopotent progenitor cells form only a negligible component in the hierarchy by studying the distribution of progenitors in human marrow, leading them to infer that HSC and earliest multipotent progenitors differentiate directly into unipotent cells. Although these data challenge fundamental beliefs, the quantitative contributions of HSC and progenitors to cell lineages could not be tracked in individual mice or persons over time. We developed a statistical method to infer the rates and probabilities of cell fate decisions in a class of stochastic branching models and used this to analyze sequence data from a rhesus macaque transplanted with lentivirally barcoded CD34+ HSC and progenitor cells. The macaque's blood granulocytes (Gr), monocytes (Mo), B cells, T cells, and NK cells were tracked over 30 months. Our quantitative framework is based on computing correlations between pairs of observable mature blood cell types across all independently barcoded lineages. The method also accounts for experimental uncertainties intrinsic to blood sampling, cell purification and PCR amplification. Specifically, our approach relies on a loss function estimator that minimizes residuals between empirical pairwise correlations across barcode lineages and analytical model-based correlations derived generally for continuous-time multi-type branching processes. We integrate over sampling distributions accounting for noise in experimental protocol and CBC counts. Candidate models represent possible hematopoietic structures and allow an arbitrary number of progenitor and mature cell types descended from each HSC. We identify best-fitting fate decision rates and initial marking levels with corresponding confidence intervals via nonlinear least squares and can assess whether a given model is statistically consistent with the data. This is the first statistical method to our knowledge for fitting stochastic models of hematopoiesis to lineage barcoding time-series, and together with the rhesus macaque data, enables quantitative analysis of in vivo dynamics in a large animal model. Using this new approach, we confirmed the major finding in Wu et al. (Cell Stem Cell, 2014) of a distinct NK cell ontogeny, i.e., that CD16+ blood NK cells do not overlap in origin with T and B cell lineages. We estimate that 13.9% of HSC and 86.1% of progenitors were initially barcoded, which is consistent with the finding by Wu that the percentage of blood cells expressing GFP stabilized at 13% after 6 months. Additionally, we estimate that HSC self-renew approximately once every 12 weeks, which is consistent with the range estimated in previous primate studies based on telomere studies (Shepherd, Blood, 2007). These initial analyses help validate our method. We then showed that Gr and Mo cells derive from a common precursor in vivo (correlation ρ ≈.9 across time). We also estimated progenitor differentiation rates and showed that Gr and Mo cells are produced up to 10- to 100-fold more rapidly than T, B and NK cells, and that each progenitor committed to the Gr/Mo lineage (i.e., CFUGM) produces thousands of mature cells per day. Importantly, we tested models requiring an ordered differentiation through defined intermediaries and found that they did not suitably fit the data compared to models allowing for non-restricted pathways. Together these analyses challenge the classic model of blood cell differentiation and provide new insights into the structure of hematopoiesis. Disclosures Dunbar: GSK/Novartis: Research Funding.

Desegregation in the south had many goals, among them was creating equitable opportunities for students in schools. Much of the literature on desegregation efforts are focused on general education and little research has been done on the effects it had on school orchestra programs. Orchestra programs in Texas schools have had a historically strong presence, but opportunities for Black string players had been rare and limited by segregation. It wasn’t until 1963 that Black students could participate in Texas All-State ensembles and 1968 before school ensemble competitions were integrated. Newspaper articles, archives, and voices of individuals that lived through these experiences were examined to gain a better understanding of what occurred during the time of desegregation in Texas schools. The predominantly Black orchestra program at Dunbar High School in Lubbock thrived despite segregation; however, it would later struggle to recover after integration plans were enacted. In an effort to satisfy desegregation laws, Black students and teachers were bussed to white schools dissolving the Black nucleus that contributed to their previous success. A historical examination of Texas string orchestra programs, competitions, and lived experiences of Black stakeholders revealed issues surrounding representation and the importance of strong role models in music.

Abstract Introduction: Mutations of the tumor suppressor p53 are detected up to 80% of esophageal squamous cell carcinoma (ESCC) cases, which in turn correlate with high metastatic rates and poor prognosis. To understand the mutant p53-mediated mechanisms in promoting ESCC metastasis, we conducted RNA-Seq and cytokine array on isogenic primary and metastatic tumor cells harvested from our mouse model of esophageal cancer harboring Trp53R172H/-, in which we have identified Colony stimulating factor 1 (Csf1) to be upregulated. Our goal is to investigate the role and mediators of CSF1 signaling through its cognate receptor CSF1R by which missense p53 mutations can promote tumor invasion and lung metastasis in ESCC. Methods: We have utilized novel L2-Cre; LSL-Trp53R172H; Rosa26LSL-YFP mice and isolated tumor cells to model metastatic ESCC. We conducted ChIP-Seq analysis for p53 on tumor cells derived from lung metastases in our mouse models. Furthermore, we have genetically and pharmacologically targeted CSF1/CSF1R signaling axis to assess its role in ESCC tumor invasion and lung metastasis. In addition to studying tumor intrinsic mechanisms, we have established quantitative multiplex immunofluorescence (qmIF) and flow cytometry approaches to characterize the changes in tumor microenvironment (TME). Results And Discussion: We demonstrate that metastatic ESCC has increased Csf1 expression compared to primary tumors, and this is dependent upon p53 mutation status, which is reinforced by the TCGA data and patient-derived tissue microarrays (TMAs). The overlay of the RNA-Seq with the ChIP-Seq analysis indicates that Csf1 is a direct gene target of p53-R172H with enriched binding motifs. Furthermore, based on the proximity ligation assay (PLA) with murine ESCC tumor cells, bromodomain and extra-terminal motif (BET) protein BRD4 interacts with p53-R172H to induce Csf1 expression. We show that the BRD4-CSF1 axis fosters tumor invasion, subcutaneous tumor growth and metastatic burden in a mutant p53 background. In accordance, upon inhibiting this signaling pathway in the tail-vein injection lung metastasis models, we have identified reduced expression of CD31+ cells and decreased infiltration of F4/80+CD163+ and F4/80+CD206+ M2-polarized macrophages at the metastatic tumor sites, indicating that the CSF1/CSF1R pathway plays a critical role in shaping the pro-metastatic and immunosuppressive TME. Finally, analysis of the esophageal cancer datasets reveals that specific p53 mutations are associated with markedly differential overall survival rates and Csf1 expression. Based upon these results, we are generating human and murine esophageal cells with distinct DNA contact and conformational p53 mutations via base editing. Conclusion: We have demonstrated novel roles and mechanisms of mutant p53-dependent CSF1/CSF1R signaling pathway in fostering ESCC tumor invasion and lung metastasis that may be applicable to other squamous cell cancers. We believe this can open up new avenues for therapeutic applications. Citation Format: Gizem Efe, Qiaosi Tang, Katherine M. Cunningham, Kensuke Sugiura, Karen Dunbar, Kausik Regunath, Kensuke Suzuki, Andres J. Klein-Szanto, Lois Resnick-Silverman, James J. Manfredi, Carol L. Prives, Anil K. Rustgi. Mutant p53-mediated CSF1/CSF1R signaling promotes tumor invasion and lung metastasis in esophageal squamous cell carcinoma [abstract]. In: Proceedings of the AACR Special Conference: Cancer Metastasis; 2022 Nov 14-17; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_2):Abstract nr B014.

A series of large-scale genomic studies has reported that clonally expanded hematopoietic cells bearing somatic mutations are increasingly prevalent with age, even in the absence of cytopenias, myelodysplasia, or leukemia. Individuals with acquired somatic mutations at a variant allele frequency (VAF) of at least 2% in genes recurrently mutated in hematologic malignancies not meeting criteria for any known hematologic disorders have been labeled as manifesting "age-related clonal hematopoiesis (ARCH)". Dominant negative or loss-of-function (LOF) mutations in genes encoding for epigenetic modifier enzymes such as DNMT3A, TET2, and ASXL1 are most common in ARCH, and individuals with ARCH are at a greater risk for cardiovascular diseases as well as hematologic malignancies. However, the relationships between these mutations, clonal expansion, and clinical outcomes are not fully elucidated due to difficulties in studying individuals with ARCH longitudinally over time in the absence of an overt clinical abnormality, and extrapolating from murine models that may not closely recapitulate human hematopoietic physiology. Since non-human primates (NHP) have a high similarity in HSPC and marrow properties to humans, and we have identified typical spontaneous ARCH mutations in aged macaques not yet identified in aged mice, we sought to generate a rhesus macaque model of human ARCH utilizing CRISPR/Cas9 technology to investigate clonal behavior and intervention strategies. We delivered a gRNA pool targeting the three most frequently mutated genes in human ARCH with Cas9 in the form of ribonucleoprotein (RNP) into HSPCs obtained from three young adult macaques, targeting a low efficiency, and the edited HSPCs were reinfused into autologous animals following total body irradiation. All macaques engrafted promptly after transplantation and maintained normal blood counts. Up to three years of long-term follow-up revealed reproducible and significant expansion of multiple HSPC clones with heterozygous TET2 LOF mutations, compared to the limited expansion of clones carrying DNMT3A and ASXL1 mutations, reaching a VAF almost 25% with doubling time of 7.5 months in circulating granulocytes of the first macaque (ZL26, Fig 1A). Although there were differences in population doubling rates between individuals, the three macaques shared the general pattern of a gradual but dramatic expansion of TET2-mutated clones, with most of the expanding indels resulting in frameshifts predicted to result in LOF. These data suggest a single mutation in TET2 is sufficient for clonal expansion, and that other intrinsic and/or extrinsic factors can regulate the pace of TET2 clonal expansion. Bone marrow of these macaques exhibited hypercellularity and myeloid-predominant skewing without dysplastic changes compared with macaques of similar age previously transplanted with HSPCs edited at non-ARCH loci. Furthermore, RNA-seq indicated that TET2-disrupted myeloid colony-forming units (CFUs) and mature cells exhibited a distinct hyperinflammatory gene expression profile. Indeed, CD14+CD163+ macrophages purified from all three ARCH macaques exhibited hyperinflammatory function, with upregulated NLRP3 inflammasome activity and increased IL-6 signaling. We hypothesized that interrupting the vicious cycle of clonal expansion driven by and driving inflammation could halt the expansion of TET2-mutated clones. To address this, we treated the animal with the fastest TET2-mutant clonal expansion (ZH63) with tocilizumab, an antibody blocking IL-6 signaling, starting 13 months after transplantation and continuing for 4 months. The TET2 mutated allele frequency in granulocytes declined by 30% by the end of the treatment and began to increase again after withdrawal (Fig 1B), suggesting that interruption of the IL-6 axis removes the selective advantage of mutant HSPCs and this repressive effect is specific to the TET2-mutant genotype. In summary, our CRISPR/Cas9-engineered rhesus macaque ARCH model recapitulates human ARCH and uncovers the impact of TET2 LOF on hematopoiesis and inflammation, as well as demonstrates the suppressive effect of IL-6 axis blockade in TET2-mutant clonal expansions. This robust NHP model will be further utilized for examining the pathophysiology of ARCH and testing of potential therapeutic interventions. Disclosures Dunbar: Novartis: Research Funding.

Háttér Dunbar társas agy hipotézise szerint az emberi intelligencia és beszédképesség az evolúció során elsősorban azért fejlődött ki olyan magas szinten, hogy az egyén átlássa és kezelni tudja a mintegy 150 főt magában foglaló csoportokban kialakuló bonyolult kapcsolati rendszereket. Kutatásunkban azt vizsgáltuk, hogy a nagy csoporton belüli, szoros kapcsolatokból álló kisebb csoportok mérete összefüggésben áll-e a személy kötődési stílusával. Ugyanakkor kíváncsiak voltunk arra is, hogy a vonás jellegű kötődési stílus hogyan függ össze a szociális hálóban található személyek — alterek — iránti kötődéssel, valamint arra, hogy az ego-nak az egyes altertípusokhoz való kötődésében találhatók-e eltérések. Módszerek Vizsgálatunkat egy 200 személyt magában foglaló mintán végeztük, akik online töltötték ki kérdőívünket. A kapcsolati háló feltérképezéséhez megkértük a résztvevőket, hogy soroljanak fel minden olyan személyt, akivel személyes kapcsolatban voltak az elmúlt hónapban. Ezután az egyes kapcsolatok értékelését kértük különféle dimenziók mentén, például hogy milyen gyakran találkoznak személyesen, érzelmileg menynyire állnak közel egymáshoz, és hogy hogyan értékelik kapcsolatuk kötődési jellemzőit. Ezenkívül a személyek saját magukra vonatkozóan is kitöltötték az ECR-R kérdőívet. Eredmények Szignifikáns pozitív kapcsolatot találtunk az ECR-R szorongást mérő alskáláján elért pontszám és a szimpátiacsoport mérete között. Az ECR-R két alskálája szignifikáns kapcsolatban van az összalteren mért ego-alter kötődési stílusokkal: minél alacsonyabb az ECR-R szorongás és elkerülés alskáláján elért érték, annál magasabb az ego-alter szinten mért, az egyes alterekhez való biztonságos kötődés, és annál alacsonyabb a bizonytalan kötődés értéke. Az ego-szinten mért és az ego-alter szinten mért kötődés összefüggései altertípusonként vizsgálva eltérést mutatnak. Következtetések A kötődési kapcsolat biztonságossága összefüggést mutat a kapcsolati háló szerkezetével, és annak méretével is, s mint ilyen fontos jellemzője lehet a kapcsolati háló szerveződésében megfigyelhető egyéni különbségeknek. Az általános, vonás jellegű kötődési stílus eltérő módon határozza meg a szociális háló egyes kapcsolati típusába tartozó személyekhez való kötődést. Az egyes altertípusokhoz fűződő eltérő kötődés arra utal, hogy a vizsgált személyek több, eltérő kötődési modellt használnak különböző személyes kapcsolataik értékelésekor, ami felnőttek körében megkérdőjelezi a monotropikus modell érvényességét.

Abstract Background: Hematopoietic stem cell (HSC) gene therapy is a new treatment paradigm that can potentially provide lifelong protection against HIV-1 infection. The basic principle is to genetically modify a patient's own HSC such that the progeny, including CD4+T cells and macrophages, are resistant to HIV-1. Given the expected low levels of the anti-HIV gene-marked cells in clinical studies, it is critical to understand how the vast number of HSC, each bearing a unique phenotype, and their mature progeny contribute to maintaining homeostatic regulation in HIV gene therapy settings. We have recently published novel and detailed insights about the long-term behavior patterns of individual HSC followed for 4 to 12 years post-transplant in our nonhuman primate (NHP) model of lentiviral gene therapy, revealing for the first time in primates the precise time point of HSC repopulation and the functional heterogeneity of HSCs (Kim, Cell Stem Cell, 2014; Goyal, BMC Biology, 2015). Consistent clonal behavior patterns have been observed in human gene therapy (Biasco, Cell Stem Cell, 2016), demonstrating the clinical relevance of our data. Here, in order to develop a systems-level understanding of HSC clonal dynamics in anti-HIV therapy settings requiring efficient immune recovery from T lymphopenia, we further analyzed HSC clonal repopulation after T-cell depletion in one of our NHP animals. Our study generated systems-level datasets useful for understanding the parameters of T-cell repopulation and homeostatic regulation in anti-HIV therapy, as well as other therapies requiring efficient immune recovery from disease- or treatment-induced T lymphopenia. Subjects and Methods: The HSC clonal behaviors in animal 95E132 have been well characterized for 16 years post-transplant. At the 16-year time point, this animal was treated with 8 doses (25 ug/kg/dose) of an anti-CD3e immunotoxin over 4 days. Hematopoietic recovery after T-cell depletion was monitored by a complete blood count, multi-color flow cytometry analysis, TCRv_ spectratyping, and a high-throughput lentiviral-tagging assay (Kim, Journal of Virology, 2010). HSC subtypes and their clonal behaviors were determined based on the clonal profiling of blood lineages, including CD4, CD8, CD20, CD14, and CD18 cells, over time. Results: The peripheral CD3+ T cells recovered in 2-3 months (Fig. 1B). Cytotoxic (CD8+) T-cell recovery was faster than that of T-helper cells. Effector and memory T cells expanded promptly after T-cell depletion, whereas the na•ve T cells had not recovered more than one year after CD3e-immunotoxin treatment. Clonal profiling analysis revealed a few dominant clones in the recovered T-cell compartment, while showing no notable clonal fluctuation in the CD18+ granulocytes over time (Fig. 1C-D). TCRv_ spectratyping showed a skewed T-cell receptor repertoire even a year after immunotoxin treatment. Conclusion: Our data can bolster our understanding of hematopoietic regulation in patients recovering from T lymphopenia. The data showed skewed a T-cell receptor repertoire and clonal dominance in the recovered T-cells after immunotoxin treatment in an aged animal, suggesting that T-cell recovery had occurred primarily as a result of peripheral T-cell expansion. A systems-level, clonal dynamics study of this extreme form of homeostatic regulation provides unique opportunities to identify and characterize the regenerative pathways, as well as the obstacles, that emerge in the process of restoring homeostasis after disease- or treatment-induced T-cell depletion. Figure 1 A. Hematopoietic recovery after CD3e-immunotoxin treatment (red arrow) was assessed at the clonal level. B. CD3+ T cells were effectively ablated by immunotoxin treatment. The T-cell percentage rebounded to the normal range by 2-3 months. C. A ternary diagram showing Myeloid-biased (black circles), Balanced (red circles), and Lymphoid-biased (green circles) HSC subtype clones. The relative position of a circle in the diagram indicates the lineage output potential toward G/M (granulocyte/monocyte), B-cell, and T-cell. The size of a circle indicates the relative frequency of a clone. D. The relative frequencies of the HSC clones in T-cell, B-cell, Granulocytes, and monocytes are shown at 1 month before (-1M), 1 month (1M) and 3 month (3M) immunotoxin treatment. The individual clones (circles) are located at the identical positions in C. Figure 1. A. Hematopoietic recovery after CD3e-immunotoxin treatment (red arrow) was assessed at the clonal level. B. CD3+ T cells were effectively ablated by immunotoxin treatment. The T-cell percentage rebounded to the normal range by 2-3 months. C. A ternary diagram showing Myeloid-biased (black circles), Balanced (red circles), and Lymphoid-biased (green circles) HSC subtype clones. The relative position of a circle in the diagram indicates the lineage output potential toward G/M (granulocyte/monocyte), B-cell, and T-cell. The size of a circle indicates the relative frequency of a clone. D. The relative frequencies of the HSC clones in T-cell, B-cell, Granulocytes, and monocytes are shown at 1 month before (-1M), 1 month (1M) and 3 month (3M) immunotoxin treatment. The individual clones (circles) are located at the identical positions in C. Disclosures Dunbar: GSK/Novartis: Research Funding. Chen:Calimmune: Membership on an entity's Board of Directors or advisory committees.

Abstract Recent advances in CRISPR/Cas9 technology allowing precise genome editing at a site of interest have enabled relevant human disease modeling and the development of corrective gene therapies for various genetic disorders. Paroxysmal nocturnal hemoglobinuria (PNH) is a hematological disorder linked to acquired somatic loss-of-function mutations disrupting the X-linked PIG-A gene in hematopoietic stem and progenitor cells (HSPC), characterized by the clinical triad of intravascular hemolysis, thrombosis and bone marrow failure, as well as clonal expansion of HSPC defective in glycosylphophatidylinositol(GPI)-linked proteins, due to loss of PIG-A enzymatic activity. There have been many attempts to model PNH utilizing conditional knockout strategies in mice, but these do not recapitulate the hemolytic phenotype or clonal dominance. Whether clonal expansion is intrinsic to PIG-A deficient HSPC or extrinsic, resulting from relative protection of PIG-A deficient HSPC and progeny cells from immune attack, is unclear. To explore the pathophysiologic mechanisms of PNH HSPC clonal expansion, we generated a relevant non-human primate model for PNH, utilizing autologous transplantation of HSPC edited with CRISPR/Cas9 at the PIG-A locus. The most efficient guide RNAs (gRNAs) targeting several sites within PIG-A exon 2 locus on the X chromosome, where most of mutations occur in patients with PNH, were selected based on efficiency of editing as screened in FRhK-4 cell lines and mobilized macaque CD34+ HSPC. Compared to editing of the control AAVS1 locus and other genes of interest, editing of all PIG-A locus sites was relatively inefficient. Autologous HSPC were transduced with ribonucleotide protein (RNP) complexes of Cas9 protein and selected gRNAs targeting either PIG-A or the AAVS1 "safe harbor" site, as an internal control, followed by transplantation into one female (ZI35) and one male (ZL19) macaque, respectively. Both animals engrafted promptly and clones acquiring the PNH loss-of-function phenotype, defined by loss of binding of FLAER, a fluorescent compound that binds to all GPI anchors, and loss of expression of lineage-specific GPI-linked proteins (CD24 for granulocytes and CD14 for monocytes) were stably maintained at levels of 0.2-0.4% for up to 19 months post-transplantation, with no evidence for intrinsic clonal expansion of PIG-A edited cells (Fig. 1A). Upon targeted deep sequencing, 0.4-1% insertions and deletions (INDELs) induced by CRISPR/Cas9 were detected, and the predominant INDEL type was identified as a single base deletion at the +1 or -1 positions of the target site consistently in granulocytes and other mature hematopoietic lineage cells from peripheral blood (PB), suggesting that initial mutations occurred in long-lasting HSPCs rather than short-term progenitor cells. Furthermore, as the PIG-A gene is located on X chromosome, we sought to investigate the difference in genome editing efficiency depending on the number of X alleles or activation state. Note that the expected INDEL frequency in completely PIG-A deficient sorted FLAERneg cells would be 100%, however, large deletions or rearrangements are not detected by standard deep sequencing methodologies. Interestingly, the mutation frequencies in total granulocytes and more importantly in sorted FLAER negative PNH cells were always much higher in male (ZL19) macaque cells than in female (ZI35) macaque cells (Fig. 1B and C). Consistently, gene editing PIG-A allele efficiency with CRISPR/Cas9 was also higher in human male B-lymphoblastoid cell lines (LCL) compared to female cells, 23.2% versus 16.6% (n=5), respectively. The finding that edited allele frequency was consistently lower in sorted FLAERneg female than male cells suggests that editing of the active X allele may be favored, potentially due to poor accessibility of inactive loci to editing machinery. In conclusion, we have successfully established a rhesus macaque model for PNH utilizing autologous transplantation of CRISPR/Cas9 edited HSPC. To date, we found no evidence for intrinsic expansion of PIG-A deficiency HSPC and hematopoietic progeny. This modeling approach could be utilized for further investigation of extrinsic or intrinsic factor responsible for clonal expansion. Furthermore, our findings provide a better insight into the relationship between CRISPR/Cas9 editing efficiency and active versus inactive X-linked genes. Figure 1. Figure 1. Disclosures Dunbar: National Institute of Health: Research Funding.

Abstract GATA2 deficiency is a rare, inherited or sporadic genetic disorder characterized by variable onset of a pleomorphic constellation of immune, hematologic and lymphatic abnormalities linked to heterozygous mutations in the Gata2 gene. Patients develop monocyte, B cell, NK cell and dendritic cell deficiencies resulting in vulnerabilities to unusual infections. Patients with GATA2 deficiency also frequently progress to bone marrow failure, myelodysplastic syndrome and/or acute myelogenous leukemia. GATA proteins are transcription factors with central roles in early embryonic development and lineage specification. GATA2 is a master regulator of hematopoiesis, implicated in the initial generation and maintenance of hematopoietic stem cells (HSC). Murine models recapitulate the human phenotype incompletely: GATA2 heterozygous knockout mice do not manifest loss of monocyte, B cells or NK cells; however, serial repopulation assays show decreased engraftment potential. Direct studies of primary HSC from patients with GATA2 deficiency are challenging due to the generally hypocellular marrow. We hypothesized that human pluripotent stem cells, particularly patient-specific iPSC, could be used to study potential developmental defects in GATA2 deficiency, overcoming a lack of primary HSC. In order to gain insights into the impact of human GATA2 deficiency on hematopoietic differentiation, we compared the single cell transcriptomes of HSPC differentiated from (i) iPSCs from a patient with GATA2 deficiency due to a mutation p.R337X (c.1009C>T) (ii) isogenic iPSCs created via homology-directed repair of Gata2 p.R337X, (iii) iPSCs from a healthy control and (iv) isogenic Gata2 heterozygous mutant iPSCs with monoallelic frameshift mutations in the second zinc finger domain. Mesodermal and hematopoietic differentiation was performed under feeder-free, defined media conditions. At day 0, iPSCs were plated in mesodermal induction media containing VEGF, SCF, Activin A and Y27632 in STEMdiff APEL media. Mesodermal induction was continued until day 4, when embryoid bodies were cultured in hematopoietic specification media with SCF, FLT3L, IL3, IL6, G-CSF and BMP4 until day 16, when CD34+CD45+ iPSC-derived hematopoietic stem and progenitor cells (iHSC) were enumerated and sorted by fluorescence-activated cell sorting. Single cell RNA-seq was performed using the 10XGenomics Chromium platform and primary analysis via CellRanger. Scater was used to filter outlier cells. Seurat as used to compute multiple manifold alignment and differential gene expression. Cell classification, pseudotemporal ordering and branch point analysis were performed with monocle. URD was used to calculate confirmatory diffusion maps and pseudotemporal ordering. We analyzed 7,855 iHSPC (2952 from GATA2-deficient patient, 241 isogenic iHSPCs after repair of Gata2 mutation, 2,605 from a healthy volunteer and 2,057 from isogenic heterozygous Gata2 knockout iHSPCs) after filtering of outliers. We computed multiple manifold alignment to mitigate batch effects. Differential gene expression across Gata2 mutation status found that 42 out of 102 (42%) target genes of GATA2 (c.f. TRANSFAC database of curated transcription factor targets) were differentially expressed with adjusted p-values less than 0.05. Semi-supervised classification of cell-types and pseudotemporal ordering via monocle revealed two branch points, consistent with developmental branchings at the level of CLP and CMP multipotent progenitors. The numbers of cells along each branch was found to be statistically different (χ2=30.07, p-value = 3e-7) with the biggest differences noted in the lymphoid branch (state 4). Differential gene expression in this branch revealed a differential up-regulation of Notch1, CD69 and FKBPs and differential down-regulation of CD14. In conclusion, iPSC/iHSPC differentiation models combined with single cell transcriptome analysis may be a valuable tool to identify pathways responsible for impaired hematopoietic/lymphatic development in GATA2 deficiency. Figure. Figure. Disclosures Dunbar: National Institute of Health: Research Funding. Winkler:National Institute of Health: Research Funding.

Abstract The classical model of hematopoietic hierarchies is being reconsidered, based on data from in vitro assays and single cell expression profiling. Recent experiments suggest that erythroid and megakaryocytic lineages might differentiate directly from multipotent hematopoietic stem/progenitor cells (HSPC) or from a highly biased subpopulations of HSPC, rather than transiting through a common MEP or CMP. We examined the clonal ontogeny of the erythroid lineage using genetic barcoding of rhesus macaque HSPC (Wu Cell Stem Cell, 2014; Koelle Blood, 2017), allowing quantitative and sensitive tracking of the in vivo clonal output of thousands of individual HSPC over time following autologous transplantation. CD34+ HSPC were lentivirally-transduced with a high diversity barcode library, with the barcode in an expressed region of the provirus, allowing barcode retrieval from DNA or RNA, with each barcode representing an individual HSPC clone. CD34+ HSPC were purified from bone marrow(BM) of 3 macaques at 3-45 months post-transplant, and plated in CFU assays. 240 colonies each of CFU-E, CFU-G and CFU-GM were plucked individually, and each colony type was pooled before DNA extraction for barcode retrieval, along with purification and barcode retrieval from concurrent BM CD34+ cells and both blood and BM T cells (T), B cells (B), granulocytes (Gr), and monocytes (Mono). The majority of barcodes retrieved from pooled CFU-E were also detected in pooled CFU-G and CFU-GM, along with purified T cells, B cells, Mono and Gr, suggesting a shared unbiased precursor pool. A small fraction of clones unique to CFU-E were identified, however, unique clones were also detected in CFU-G and in CFU-GM pools, likely reflecting low frequency clones that were to be represented randomly in the pooled CFU of each lineage. To overcome the sampling bias inherent in colony assays on any reasonable colony number, we FACS purified CD71+/CD45- nucleated maturing erythroid lineage cells (nRBC) from the BM, and compared nRBC to other lineages purified concurrently from the same BM sample. There was very high correlation of barcode contributions between BM nRBC and other BM-produced lineages, with the highest correlation between nRBC and both Gr and Mono (r> 0.9), whether at earlier or later time points. We investigated whether RNA barcode retrieval could be utilized for clonal tracking, allowing analysis of anucleate circulating RBC and thus a more global analysis of hematopoiesis compared to local BM production at a limited number of sites. We have reported that clonal output from individual HSPC remains highly geographically restricted within the BM for months-years post-transplant. We compared fractional contributions of DNA and RNA barcodes retrieved from the same sample of each lineage. There was very high correlation between DNA and RNA barcode contributions to T, B, NK, Gr and Mono lineages (r= 0.85±0.04), suggesting the differentiation pathway for these lineages does not impact significantly on expression level of barcodes from the proviral promoter, and RNA fractional contributions in these lineages reflect the clonal representation of cells in a sample. However, nRBC DNA and RNA barcode contributions were less closely related (r= 0.62), suggesting that erythroid differentiation was more likely to alter expression from loci in a manner disconnecting RNA barcode expression from clonal representation of cells in a sample, and suggesting that RNA barcode retrieval may not be ideal for comparing erythroid cells to other lineages. However, tracking RNA barcodes can be used to assess clonal stability in circulating RBC over time, and revealed very stable clonal contributions to erythropoiesis for as long as 4 years post-transplant. Finally, we used RNA barcode retrieval to compare clonal contributions between circulating platelets and other lineages. Whether DNA or RNA was used for T, B, Gr, and Mono clonal mapping, at steady state platelet RNA barcodes were clonally closely related to other lineages. But preliminary data suggests that a unique set of clones is newly recruited to contribute only to platelets following inflammatory stimuli. The presence of a separate pool of platelet-biased HSPC contributing following inflammation has been suggested by prior in vitro assays, but our model may provide the first clonal in vivo confirmation of a unique inflammation-related platelet-biased HSPC pool. Disclosures Dunbar: Novartis/GSK to institute: Research Funding.

Abstract Abstract 2957 Poster Board II-933 We recently reported the development of an acute myeloid leukemia in a rhesus macaque transplanted with autologous CD34+ cells transduced with a murine stem cell virus-derived replication defective retrovirus vector expressing only marker genes under control of the strong MCSV LTR. This animal had an unusual clonal reconstitution pattern the first year following transplant, with a single transduced myeloid progenitor cell clone accounting for up to 80% of then normal myelopoiesis (Kelly, 2003). The same vector-containing clone then transformed to AML five years following transplantation, and each tumor cell was shown to contain two vector insertions, one localized 20 kb upstream the CDw92 gene on chromosome 9, and the second localized in the first intron of BCL2A1 on chromosome 15 (Seggewiss, 2006), a gene belonging to the anti-apoptotic BCL2 family not previously linked to myeloid leukemia. BCL2A1 was highly expressed in the tumor cells. This tumor was the first hematopoietic malignancy reported in a recipient of primitive cells transduced with a replication-incompetent vector containing only marker genes, and suggested that BCL2A1 could have potent effects on hematopoiesis. To further investigate the impact of the BCL2A1 gene product on normal and malignant hematopoiesis, we cloned the murine and human HA-tagged BCL2A1 cDNAs into lentiviral vectors and transduced the murine BaF3 hematopoietic cell line as a model to study the impact of expression of these proteins in vitro. We confirmed the role of BCL2A1 as an anti-apoptotic protein. The proliferation and survival of the BaF3 cells is dependant on IL-3. Upon removal of IL-3 from the media, BaF3 cells underwent an arrest in the G1 phase of the cycle. Untransduced cells or cells transduced with the empty lentiviral vector were 45% apoptotic, but this fraction decreased to 30 and 15% respectively with the cells transduced with murine and human BCL2A1. Similar results were obtained in murine 32Dcl3 cells and human UT7/Epo-S1 cells, two cells line that are respectively dependant on IL-3 and erythropoietin. In order to study the in vivo impact of BCL2A1 on hematopoiesis, C57/bl6 (Ly5.2) mice have been transplanted with primary bone marrow cells (from C57/bl6 (Ly5.1)) transduced with the BCL2A1 and control vectors, and have been followed for in vivo expansion of transduced clones and development of leukemia. The mice cohort consisted of 5 MOCK controls, 15 control vector expressing GFP only, and 15 murine BCL2A1. We frequently checked the blood counts and analyzed the lineage of blood by FACS. Mice transplanted with marrow cells transduced with the BCL2A1 vector had higher overall marking levels in the blood compared to the vector control (80% vs. 10% cells GFP+ respectively). Interestingly, preliminary histopathology revealed that 7 mice from the BCL2A1 group, but none of the control groups developed a further to be classified very poorly differentiated hematologic malignancy consisting of circulating blasts, splenomegaly, and lymphadenopathy. Cells responsible for this fatal disease were not stained by markers used for FACS analysis or by immunohistochemistry. The median overall survival was significantly different for mice treated with the vector (420 days) and mice treated with BCL2A1 (328 days). The median disease free survival was more striking as the median could not be defined for the vector while it was of 397 days for BCL2A1. Two hundred and fifty three days after the transplantation we selected 3 primary mice from BCL2A1 and vector control groups to perform secondary transplant. Less than a month after reinfusion all BCL2A1 mice developed a disease characterized by high white blood cell counts with a majority of undifferenciated cells, as well as splenomegaly, and hepatomegaly. These results were repeated in a second set of secondary transplant carried out 289 days after transplantation confirming that the disease is transplantable. The preliminary histopathology findings showed a similar phenotype to the lymphatic malignancy seen in the primary mice. In conclusion, we have confirmed the anti-apoptotic role of BCL2A1, and we are now investigating its role in hematopoiesis and leukemogenesis. We are investigating the exact phenotype of the disease seen in primary and secondary mice in order to clarify the role of BCL2A1 as a survival factor. Disclosures: Dunbar: ASH: Honoraria.

ASSESSMENT OF PARALLEL SIGNALING PATHWAYS IN UTERINE MYOCYTES STIMULATED WITH VARIOUS SMOOTH MUSCLE AGONISTS H.N. Aguilar, B.F. Mitchell 1 TRACTOGRAPHY: A NOVEL TECHNIQUE TO IMAGE FIBER TRACTS OF THE SPINAL CORD Fahad Alkherayf, Eve Tsai, Arturo Cardenas-Blanco, Alain Berthiaume, Brien Benoit, John Sinclair 1 MODULATION OF OSTEOCLASTOGENESIS IN INFLAMMATORY JOINT DISEASES H. Allard-Chamard, M. Durant, A.J. de Brum-Fernandes, G. Boire, S.V. Komarova, S.J. Dixon, S.M. Sims, R. Harison, M.F. Manolson 2 “THE RIGHT THING TO DO? A CRITICAL ANALYSIS OF PUBLIC HEALTH ETHICS, RIGHTS DISCOURSE, AND THE EXPANSION OF ANTIRETROVIRAL THERAPY (ART)” Berkhout, SG, Anderson, S, Tyndall, MW 2 COST-EFFECTIVENESS OF IMMEDIATE BASELINE COMPUTED TOMOGRAPHY VS. MAGNETIC RESONANCE IMAGING OF ACUTE ISCHEMIC STROKE IN ONTARIO PATIENTS WHO PRESENT WITH SYMPTOMS SUGGESTIVE OF STROKE KR Burton, G. Mery 3 CHITOSAN-MEDIATED FGF18 DELIVERY FOR ASSISTED BONE REPAIR A. Carli, M. Lavertu, C. Gao, A. Merzouki, M.D. Buschmann, J.E. Henderson, E.J.Harvey 3 ACTIVE PI3K-AKT SIGNALING PROMOTES THE METASTATIC POTENTIAL OF ASCITES-DERIVED EPITHELIAL OVARIAN CANCER CELLS Correa RJM, Ramos-Valdes Y, Bertrand M, Lanvin D, Préfontaine M, Sugimoto AK, Lewis JD, Shepherd TG, DiMattia GE 4 MECHANISMS OF K65R, D67N, K103N, V106M AND M184V RESISTANCE DEVELOPMENT IN SUBTYPE-B AND C HIV-1 Dimitrios Coutsinos, Cedric F. Invernizzi, Daniela Moisi, Maureen Oliveira, Hongtao Xu, Bluma G. Brenner, Mark A. Wainberg 4 A MODEL TO DETERMINE FACTORS INVOLVED IN THE INDUCTION OF AN IN VIVO CTL RESPONSE Dissanayake D, Ohashi PS 5 P63 ANTAGONIZES P53 TO PROMOTE THE SURVIVAL OF EMBRYONIC NEURAL PRECURSOR CELLS Sagar B. Dugani, Annie Paquin, Masashi Fujitani, David R. Kaplan, Freda D. Miller 5 SPINAL LOCOMOTOR NETWORK MODULATION BY ENDOGENOUS SEROTONIN IN THE ISOLATED NEONATAL MOUSE SPINAL CORD Dunbar MJ, Whelan PJ 6 THE TUMOR PROMOTING AND REPRESSING EFFECTS OF INTEGRIN-LINKED KINASE ARE DIFFERENTIATED BY JNK1 IN HUMAN CANCER CELLS Adam David Durbin, Gregory Edward Hannigan, David Malkin 6 INCREASED EXCITATION IN MICE OVER-EXPRESSING NEUROLIGIN-1 IS ASSOCIATED WITH IMPAIRED LONG-TERM POTENTIATION AND LEARNING AND MEMORY Brennan D Eadie, Timal Kannangara, Regina Dalhaus, Rochelle M Hines, Yu-Tian Wang, Alaa El-Husseini, Brian R Christie 7 A NOVEL ROLE FOR CDK5/P35 IN MEDULLOBLASTOMA FORMATION Friesen AN, Shin J, Law V, Lee YS, Mckinnon P, Lee KY 7 ALTERED PSYCHOSOCIAL BEHAVIOUR AND STRESS RESPONSE FOLLOWING ‘MINOR’ STROKE IN THE RAT Krista Hewlett, Meighan Kelly, Dale Corbett 8 TUMOUR PATHOLOGY PREDICTS MICROSATELLITE INSTABILITY IN COLORECTAL CANCER AJ Hyde, D Fontaine, S Stuckless, RC Green, A Pollett, M Simms, P Parfrey, HB Younghusband 8 PROTEINASE-ACTIVATED RECEPTOR-2 (PAR2) IS A POTENTIAL TARGET FOR THE ANTI-INFLAMMATORY EFFECTS OF INSULIN Eric Hyun, Rithwick Ramachandran, Nicolas Cenac, Steeve Houle, Amit Saxena, Roland S. Liblau, Morley Hollenberg, Nathalie Vergnolle 9 CHEMOSENSITIVE PROPERTIES OF THE VENTRAL MEDULLA IN VITRO Kalf Daniel J, Wilson Richard JA 9 NOVEL DOPAMINE RECEPTOR-N TYPE CALCIUM CHANNEL INTERACTIONS: POTENTIAL THERAPEUTIC TARGETS FOR DISORDERS ASSOCIATED WITH ABERRANT DOPAMINERGIC SIGNALLING Alexandra E. Kisilevsky, Sean J. Mulligan, Christophe Altier, Mircea C. Iftinca, Diego Varela, Chao Tai, Lina Chen, Shahid Hameed, Jawed Hamid, Brian A. MacVicar, Gerald W. Zamponi 10 TRUNCATION OF THE C-TERMINAL DOMAIN OF CONNEXIN43 INCREASES INFARCT VOLUME DURING STROKE Kozoriz MG, Bechberger JF, Bechberger GR, Suen MWH, Moreno AP, Maass K, Willecke K, Naus CC 10 EVALUATION OF THE DELIVERABILITY AND TOLERABILITY OF INTENSIVE WEEKLY DOUBLET ADJUVANT CHEMOTHERAPY IN NON SMALL CELL LUNG CANCER M. Sara Kuruvilla, Lorraine Martelli-Reid, J. R. Goffin, A. Arnold, Peter M. Ellis 11 A POLICY-ORIENTED SYSTEMATIC REVIEW OF THE SAFETY AND EFFICACY OF ENDOSCOPIC THERAPIES FOR THE TREATMENT OF BARRETT’S ESOPHAGUS Lau D, Menon D, Stafinski T, Topfer LA, Walker J 11 THE SRC-LIKE ADAPTOR PROTEIN, SLAP, PLAYS A ROLE IN MONOCYTE-DERIVED DENDRITIC CELL MATURATION Larissa Liontos, L Dragone, A Weiss, C J McGlade 12 SWEET PEE: A NEW MOUSE MODEL FOR GLOMERULOCYSTIC KIDNEY DISEASE AND GLUCOSURIA J Ly, J Rossant, L Oxborne, C McKerlie, A Flenniken, S Quaggin 12 CARDIOGENIC SHOCK IN ASPHYXIATED NEONATE PIGLETS: IS COMBINATION INOTROPE THERAPY BETTER THAN HIGH-DOSE DOPAMINE? N. Manouchehri, P.-Y. Cheung, C. Joynt, T. Churchill, D. Bigam 13 THE RELATIONSHIP BETWEEN FLOW-MEDIATED DILATION, HYPEREMIC SHEAR STRESS, AND VARIOUS ANTHROPOMETRIC INDICES OF OBESITY Martin BJ, Title LM, Verma S, Charbonneau F, Buithieu J, Lonn EM, Anderson TJ 13 RAPID LOCALIZATION OF NEUTROPHILS TO SITES OF CELL DEATH BY MAC1-DEPENDENT ADHESION AND INTRAVASCULAR CRAWLING McDonald B, Menezes GB, Kubes P 14 THE ROLE OF SHIP-1 IN CEACAM1-MEDIATED HOST RESPONSES TO NEISSERIA GONORRHOEAE INFECTION Gordon G McSheffrey, S D Gray-Owen 14 USING VOLTAGE-SENSITIVE DYES TO RECORD BRAIN ACTIVITY IN NATURALLY MOVING MICE McVea DA, Mohajerani MH, Fingas M, Murphy TH 15 POTENTIAL MECHANICAL INFLUENCE IN MICROVASCULAR PATHOLOGY IN THE ACL DEFICIENT RABBIT KNEE Daniel Miller 15 OSTEOBLAST MECHANOSENSITIVITY: THE ROLE OF HYDROSTATIC PRESSURE Kenneth A. Myers, Timothy Douglas, Ricarda Hess, Justin Parreno, Jerome B. Rattner, Dieter Scharnweber, Nigel G. Shrive, David A. Hart 16 ENDOTHELIAL PROGENITOR CELLS FOR HEALING AND ANGIOGENESIS IN A SEGMENTAL BONE DEFECT MODEL: A COMPARISON WITH MESENCHYMAL STEM CELLS Nauth A, Li R, Schemitsch EH 16 DELAY OF DNA METHYLATION IN PERINATAL MALE GERM CELLS IN THE ABSENCE OF DNMT3L RESULTING IN INFERTILITY Kirsten Niles, Sophie La Salle, Christopher Oakes, Jacquetta Trasler 17 INVESTIGATING CRMP4 FUNCTION IN CNS NERVE REGENERATION S. Ong Tone, S. Kanagal, A. Wilson, Y.Z. Alabed, A. Di Polo, A.E. Fournier 17 A NOVEL, DNA DAMAGE-DEPENDENT REGULATORY PATHWAY FOR AKT IN VIVO Andrew J. Perrin, W. Brent Derry 18 CHOP AS A TARGET FOR PRESERVATION OF TRANSPLANTED ISLET GRAFT MASS Potter K, Dai L, Verchere CB 18 TREATMENT OF ACHILLES TENDINOPATHY R Ram, C Patel, D Wiseman, W Meeuwisse, JP Wiley 19 PLACENTAL LACTOGEN FUNCTION IN POST-IMPLANTATION MURINE PREGNANCY Saara M. Rawn, James C. Cross 19 DECODING NEURAL SIGNALS FROM MULTIELECTRODE ARRAYS IN THE PRIMATE DORSOLATERAL PREFRONTAL CORTEX Sachs A.J, Pieper F, Martinez-Trujillo J.C. 20 THE ROLE OF TRANSFORMING GROWTH FACTOR ALPHA IN A MOUSE MODEL OF OSTEOARTHRITIS Usmani S.E, Appleton C.T.G., Welch I.D, Beier F. 20 SKIN-DERIVED STEM CELLS ACT AS FUNCTIONAL SCHWANN CELLS WHEN TRANSPLANTED INTO LESIONED PERIPHERAL NERVE Sarah K. Walsh, Rajiv Midha 21 TLR4 MEDIATES SUSCEPTIBILITY TO STREPTOZOTOCIN-INDUCED DIABETES C Westwell-Roper, G Soukhatcheva, MJH Hutton, JP Dutz, CB Verchere 21 A FUSION OF GMCSF AND IL-21 (GIFT-21) POTENTLY INDUCES INFLAMMATION AND APOPTOSIS THROUGH SIGNALS DOWNSTREAM OF THE IL-21R ALPHA CHAIN Patrick Williams, Shala Yuan, Jessica Cuerquis, Elena Birman, Kathy Ann Forner, Jacques Galipeau 22

AbstractBased on the research done by Dunbar and the resulting Social Brain Hypothesis, the present study introduced a mathematical model for the development of follower numbers and the number of followed accounts regarding users/influencers of Social Media platforms. Under very simple assumptions the mathematical model suggests that an universal upper bound to follower and followed numbers exists. The theoretical upper bound is then empirically validated by using a representative data set of 255 influencers on Instagram from the field of women’s fashion. The follower numbers show convergence to a common boundary for the years 2018 to 2019 and stagnation for 2019 to 2020, while the number of followed accounts show stagnation for 2018 to 2019 and convergence for 2019 and 2020. The model in conjunction with its empirical validation therefore provides the mathematical background to establish the socio-biological Social Brain Hypothesis in the field of influencer marketing in regards to Social Media platforms.

AbstractWe discuss the structure of human relationship patterns in terms of a new formalism that allows to study resource allocation problems where the cost of the resource may take continuous values. This is in contrast with the main focus of previous studies where relationships were classified in a few, discrete layers (known as Dunbar’s circles) with the cost being the same within each layer. We show that with our continuum approach we can identify a parameter $$\eta $$ η that is the equivalent of the ratio of relationships between adjacent circles in the discrete case, with a value $$\eta \sim 6$$ η ∼ 6 . We confirm this prediction using three different datasets coming from phone records, face-to-face contacts, and interactions in Facebook. As the sample size increases, the distributions of estimated parameters smooth around the predicted value of $$\eta $$ η . The existence of a characteristic value of the parameter at the population level indicates that the model is capturing a seemingly universal feature on how humans manage relationships. Our analyses also confirm earlier results showing the existence of social signatures arising from having to allocate finite resources into different relationships, and that the structure of online personal networks mirrors those in the off-line world.

This paper describes a study in which the pattern of distribution of the number of friends among users of the Vkontakte social network among residents of eight large cities of the CIS (Moscow, St. Petersburg, Almaty, Novosibirsk, Tashkent, Kiev, Yekaterinburg, Pavlodar) was studied. Experimental data show that this distribution is of a similar nature for all selected cities. A semi-empirical model was built, on the basis of which an explicit form of theoretical dependence was obtained, describing the nature of the distribution of the number of mutual contacts (“friends”) of users of social online networks. It is shown that this theoretical dependence agrees with satisfactory accuracy with experimental data for a sufficiently large sample of cities. It is established that the Dunbar number, which is included in the dependencies considered as a control parameter, is a characteristic of the communication environment of each specific city and correlates with the population of the city.

An enduring problem in the assembly of Laurentia is uncertainty about the nature and timing of magmatism, deformation, and metamorphism in the Paleoproterozoic Wisconsin magmatic terranes, which have been variously interpreted as an intra-oceanic arc, foredeep or continental back-arc. Resolving these competing models is difficult due in part to a lack of a robust time-frame for magmatism in the terranes. The northeast part of the terranes in northern Wisconsin (USA) comprise mafic and felsic volcanic rocks and syn-volcanic granites thought to have been emplaced and metamorphosed during the 1890−1830 Ma Penokean orogeny. New in situ U-Pb geochronology of igneous zircon from the volcanic rocks (Beecher Formation), and from two tonalitic plutons (the Dunbar Gneiss and Newingham Tonalite) intruding the volcanic rocks, yielded crystallization ages ranging from 1847 ± 10 Ma to 1842 ± 7 Ma (95% confidence). Thus, these rocks record a magmatic episode that is synchronous with bimodal volcanism in the Wausau domain and Marshfield terrane farther south. Our results, integrated with published data into a time-space diagram, highlight two bimodal magmatic cycles, the first at 1890−1860 Ma and the second at 1845−1830 Ma, developed on extended crust of the Superior Craton. The magmatic episodes are broadly synchronous with volcanogenic massive sulfide mineralization and deposition of Lake Superior banded iron formations. Our data and interpretation are consistent with the Penokean orogeny marking west Pacific-style accretionary orogenesis involving lithospheric extension of the continental margin, punctuated by transient crustal shortening that was accommodated by folding and thrusting of the arc-back-arc system. The model explains the shared magmatic history of the Pembine-Wausau and Marshfield terranes. Our study also reveals an overprinting metamorphic event recorded by reset zircon and new monazite growth dated at 1775 ± 10 Ma suggesting that the main metamorphic event in the terranes is related to the Yavapai-interval accretion rather than the Penokean orogeny.

Abstract The development Open Source Software fundamentally depends on the participation and commitment of volunteer developers to progress on a particular task. Several works have presented strategies to increase the on-boarding and engagement of new contributors, but little is known on how these diverse groups of developers self-organise to work together. To understand this, one must consider that, on one hand, platforms like GitHub provide a virtually unlimited development framework: any number of actors can potentially join to contribute in a decentralised, distributed, remote, and asynchronous manner. On the other, however, it seems reasonable that some sort of hierarchy and division of labour must be in place to meet human biological and cognitive limits, and also to achieve some level of efficiency. These latter features (hierarchy and division of labour) should translate into detectable structural arrangements when projects are represented as developer-file bipartite networks. Thus, in this paper we analyse a set of popular open source projects from GitHub, placing the accent on three key properties: nestedness, modularity and in-block nestedness –which typify the emergence of heterogeneities among contributors, the emergence of subgroups of developers working on specific subgroups of files, and a mixture of the two previous, respectively. These analyses show that indeed projects evolve into internally organised blocks. Furthermore, the distribution of sizes of such blocks is bounded, connecting our results to the celebrated Dunbar number both in off- and on-line environments. Our conclusions create a link between bio-cognitive constraints, group formation and online working environments, opening up a rich scenario for future research on (online) work team assembly (e.g. size, composition, and formation). From a complex network perspective, our results pave the way for the study of time-resolved datasets, and the design of suitable models that can mimic the growth and evolution of OSS projects.

Hotspots of Cultural InnovationIn the 1960s, a long list of poets, writers, and musicians flocked to the Chelsea Hotel, 222 West 23rd Street, New York (Tippins). Among them Bob Dylan, who moved in at the end of 1964, Leonard Cohen, who wrote Take This Longing dedicated to singer Nico there, and Patti Smith who rented a room there together with Robert Mapplethorpe in 1969 (Smith; Bell; Simmons). They all benefited not just from the low rents, but also from the close, often intimate, presence of other residents who inspired them to explore new creative paths. Around the same time, across the Atlantic, the Indica Bookshop and Gallery, 6 Mason’s Yard, London played a similar role as a meeting place for musicians, artists and hangers-on. It was there, on the evening of 9 November 1966, that John Lennon attended a preview of Yoko Ono's first big solo exhibition, Unfinished Paintings and Objects. Legend has it that the two met as Lennon was climbing up the ladder of Ono’s installation work ‘Ceiling Painting’, and reaching out to a dangling magnifying glass in order to take a closer look at the single word ‘YES’ scribbled on a suspended placard (Campbell). It was not just Lennon’s first meeting with Yoko Ono, but also his first run into conceptual art. After this fateful evening, both Lennon’s private life and his artistry would never be the same again. There is already a rich body of literature on the geography of music production (Scott; Kloosterman; Watson Global Music City; Verboord and Brandellero). In most cases, these studies deal with the city or neighbourhood scales. Micro-geographies of concrete places are rarer, with some notable exceptions that focus on recording studios and on specific venues (cf. Gibson; Watson et al.; Watson Cultural Production; van Klyton). Our approach focuses on concrete places that act more like third spaces – something in between or even combining living and working. Such places enable frequent face-to-face meetings, both planned and serendipitous, which are crucial for the exchange of knowledge. These two spaces represent iconic cultural hotspots where innovative artists, notably (pop) musicians, came together in the 1960s. Because of their many famous visitors and residents, both spaces are well documented in (auto)biographies, monographs on art scenes in London and New York, as well as in newspapers. Below, we will explore how these two spaces played an important role at a time of cultural revolution, by connecting people and scenes to the micro geography of concrete places and by functioning as nodes of knowledge exchange and, hence, as milieus of innovation.Art Worlds, Scenes and Places The romantic view that artists are solitary geniuses was discarded already long ago and replaced by a conceptualization that sees them as part of broader social configurations, or art worlds. According to Howard Becker (34), these art worlds consist “of all the people necessary to the production of the characteristic works” – in other words, not just artists, but also “support personnel” such as sound engineers, editors, critics, and managers. Without this “resource pool” the production of art would be virtually impossible. Art worlds are also about the consumption of art. The concept of scene has been used to articulate the local processes of taste making and reputation building, as they “provide ways of social belonging attuned to the demands of a culture in which individuals increasingly define themselves” (Silver et al. 2295). Individuals who share certain aesthetic preferences come together, both socially and spatially (Currid) and locations such as cafés and nightclubs offer important settings where members of an art world may drink, eat, meet, gossip, and exchange knowledge. The urban fabric provides an important backdrop for these exchanges: as Jane Jacobs (181) observed, “old ideas can sometimes use new buildings. New ideas must come from old buildings.” In order to function as relational spaces, these amenities have to meet two sets of conditions. The first set comprises the locational characteristics, which Durmaz identifies as centrality and proximity. The second set relates to socio-economic characteristics. From an economic perspective, the amenity has to be viable– either independently or through patronage or state subsidies. Becoming a cultural hotspot is not just a matter of good bookkeeping. The atmosphere of an amenity has to be tolerant towards forms of cultural and social experimentation and, arguably, even transgression. In addition, a successful space has to have attractors: persons who fulfil key roles in a particular art world in evaluation, curation, and gatekeeping. To what extent did the Indica Gallery and the Chelsea Hotel meet these two sets of conditions in the 1960s? We turn to this question now.A Hotel and a GalleryThe Indica Gallery and the Chelsea Hotel were both highly central – the former located right in the middle of St. James’s in the central London Borough of Westminster (cf. Kloosterman) and the latter close to Greenwich Village in Manhattan. In the post-war, these locations provided a vacant and fertile ground for artists, who moved in as firms and wealthier residents headed for the green suburbs. As Ramanathan recounts, “For artists, downtown New York, from Chambers Street in Tribeca to the Meatpacking District and Chelsea, was an ideal stomping ground. The neighbourhoods were full of old factories that had emptied out in the postwar years; they had room for art, if not crown molding and prewar charm” (Ramanathan). Similarly in London, “Despite its posh address the area [the area surrounding the Indica Gallery] then had a boho feel. William Burroughs, Brion Gysin and Anthony Blunt all had flats in the same street.” (Perry no pagination). Such central locations were essential to attract the desired attention and interest of key gatekeepers, as Barry Miles – one of Indica’s founding members - states: “In those days a gallery virtually had to be in Mayfair or else critics and buyers would not visit” (Miles 73). In addition, the Indica Gallery’s next-door neighbour was the Scotch of St James club. The then up and coming singer Marianne Faithfull, married to Indica founder John Dunbar, reportedly “needed to be seen” in this “trendy ‘in’ club for the new rock aristocracy” (Miles 73). Undoubtedly, their cultural importance was also linked to the fact that they were both located in well-connected budding global cities with a strong media presence (Krätke).Over and above location, these spaces also met important socio-economic conditions. In the 1960s, the neighbourhood surrounding the Chelsea Hotel was in transition with an abundance of available and affordable space. After moving out of the Chelsea Hotel, Patti Smith and Robert Mapplethorpe (Smith) had no difficulty finding a cheap loft to rent nearby. Rates in the Chelsea Hotel – when they were settled, that is - were incredibly low to current standards. According to Tippins (350), the typical Chelsea Hotel room rate in 1967 was $ 10 per week, which would amount to some $ 67.30 per week in 2013. Again, a more or less similar story can be told for the Indica Gallery. When Barry Miles, Peter Asher and John Dunbar founded the Gallery in September 1965, the premises were empty and the rent was low: "We paid 19 quid a week rent" according to John Dunbar (Perry). These cheap spaces provided fruitful economic conditions for cultural experimentation. Innovative relational spaces require not only accessibility in spatial and financial terms, but also an atmosphere conducive to cultural experimentation. This implies some kind of benevolent, preferably even stimulating, management that is willing and able to create such an atmosphere. At the Chelsea Hotel and Indica Gallery alike, those in charge were certainly not first and foremost focused on profit maximisation. Instead they were very much active members of the art worlds themselves, displaying a “taste for creative work” (Caves) and looking for ways in which their spaces could make a contribution to culture in a wider sense. This holds for Stanley Bard who ran the Chelsea Hotel for decades: “Working besides his father, Stanley {Bard} had gotten to know many of these people. He had attended their performances and exhibitions, read their books, and had been invited to their parties. Young and malleable, he soon came to see the world largely from their point of view” (Tippins 166). Such affinity with the artistic scene meant that Bard was more than accommodating. As Patti Smith recalls (100), “you weren’t immediately kicked out if you got behind on the rent … Mostly everybody owed Bard something”. While others recall a slightly less flexible attitude towards missed rents - “… the residents greatly appreciated a landlord who tolerated everything, except, quite naturally, a deficit” (Tippins 132) – the progressive atmosphere at the Chelsea was acknowledged by many others. For example, “[t]he greatest advantage of life at the Chelsea, [Arthur] Miller had to acknowledge, was that no one gave a damn what anyone else chose to do sexually” (Tippins 155).Similarly at the Indica Gallery, Miles, Asher and Dunbar were not first and foremost interested in making as much money as possible. The trio was itself drawn from various artistic fields: John Dunbar, an art critic for The Scotsman, wanted to set up an experimental gallery with Peter Asher (half of the pop duo Peter & Gordon) and Barry Miles (painter and writer). When asked about Indica's origins, Dunbar said: "There was a reason why we did Indica in the first place: to have fun" (Nevin). Recollections of the Gallery mention “a brew pot for the counterculture movement”, (Ramanathan) or “a haven for the free-wheeling imagination, a land of free expression and cultural collaboration where underground seeds were allowed to take root” (Campbell-Johnston).Part of the attraction of both spaces was the almost assured presence of interesting and famous persons, whom by virtue of their fame and appeal contributed to drawing others in. The roll calls of the Chelsea Hotel (Tippins) and of the Indica Gallery are impressive and partly overlapping: for instance, Allen Ginsberg was a notable visitor of the Indica Gallery and a prominent resident of the Chelsea Hotel, whereas Barry Miles was also a long-term resident of the Chelsea Hotel. The guest books read as a cultural who-is-who of the 1960s, spanning multiple artistic fields: there are not just (pop) musicians, but also writers, poets, actors, film makers, fashion designers, and assorted support personnel. If innovation in culture, as anywhere else, is coming up with new combinations and crossovers, then the cross-fertilisation fostered by the coming together of different art worlds in these spaces was conducive to these new combinations. Moreover, as the especially the biographies of Bob Dylan, Paul McCartney, Leonard Cohen, and Patti Smith testify, these spaces served as repositories of accessible cultural capital and as incubators for new ideas. Both Leonard Cohen and Patti Smith benefited from the presence of Harry Smith who curated the Anthology of American Music at the Chelsea Hotel. As Patti Smith (115) recalls: “We met a lot of intriguing people at the Chelsea but somehow when I close my eyes to think of them, Harry is always the first person I see”. Leonard Cohen was also drawn to Harry Smith: “Along with other assorted Chelsea residents and writers and music celebrities who were passing through, he would sit at Smith’s feet and listen to his labyrinthine monologue” (Simmons 197).Paul McCartney, actively scanning the city for new and different forms of cultural capital (Miles; Kloosterman) could tap into different art worlds through the networks centred on the Indica Gallery. Indeed he was credited with lending more than a helping hand to Indica over the years: “Miles and Dunbar bridged the gap between the avant-garde rebels and the rock stars of the day, principally through their friendship with Paul McCartney, who helped to put up the shop’s bookshelves, drew its flyers and designed its wrapping paper. Later when Indica ran into difficulties, he lent his friends several thousands of pounds to pay their creditors” (Sandbrook 526).Sheltered Spaces Inevitably, the rather lenient attitude towards money among those who managed these cultural breeding spaces led them to serious financial difficulties. The Indica Gallery closed two years after opening its doors. The Chelsea Hotel held out much longer, but the place went into a long period of decline and deterioration culminating in the removal of Stanley Bard as manager and banishment from the building in 2007 (Tippins). Notwithstanding their patchy record as viable business models, their role as cultural hotspots is beyond doubt. It is possibly because they offered a different kind of environment, partly sheltered from more mundane moneymaking considerations, that they could thrive as cultural hotspots (Brandellero and Kloosterman). Their central location, close to other amenities (such as night clubs, venues, cafés), the tolerant atmosphere towards deviant lifestyles (drugs, sex), and the continuous flow of key actors – musicians of course, but also other artists, managers and critics – also fostered cultural innovation. Reflecting on these two spaces nowadays brings a number of questions to the fore. We are witnessing an increasing upward pressure on rents in global cities – notably in London and New York. As cheap spaces become rarer, one may question the impact this will have on the gestation of new ideas (cf. Currid). If the examples of the Indica Gallery and the Chelsea Hotel are anything to go by, their instrumental role as cultural hotspots turned out to be financially unsustainable against the backdrop of a changing urban milieu. The question then is how can cities continue to provide the right set of conditions that allow such spaces to bud and thrive? As the Chelsea Hotel undergoes an alleged $40 million dollar renovation, which will turn it into a boutique hotel (Rich), the jury is still out on whether central urban locations are destined to become - to paraphrase John Lennon’s ‘In my life’, places which ‘had their moments’ – or mere repositories of past cultural achievements.ReferencesAnderson, P. “Watch this Space.” Sydney Morning Herald, 19 Apr. 2014.Becker, H.S. Art Worlds. Berkeley: University of California Press, 1982.Bell, I. Once upon a Time: The Lives of Bob Dylan. Edinburgh/London: Mainstream Publishing, 2012.Brandellero, A.M.C. The Art of Being Different: Exploring Diversity in the Cultural Industries. Dissertation. Amsterdam: University of Amsterdam, 2011.Brandellero, A.M.C., and R.C. 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Abstract Background We evaluated utilization of emtricitabine/tenofovir disoproxil fumarate or tenofovir alafenamide (F/TDF, F/TAF) among PN after the approval of F/TAF for PrEP in the US. Methods EMR and dispensing data from Trio Health HIV Research Network were used for this retrospective observational study. The study included HIV-negative PN ≥ 18 years with first dispense of daily oral PrEP (≥30-day supply) between 10/19-5/21 followed for ≥6 mo; individuals with hepatitis B or post-exposure prophylaxis were excluded. Prescription adherence, measured as proportion of days covered (PDC; mean and proportion with PDC ≥50, 70, and 80%) and time to regimen discontinuation (no drug >3 mo) or switch (TRD; Kaplan-Meier analysis) were compared between regimens. Characteristics associated with PDC and time to first regimen stop (switch/discontinuation) were evaluated using generalized linear regression and Cox proportional hazard models, respectively. Results Of 1330 PrEP starts, 86% (1144) were dispensed F/TAF vs 14% F/TDF (186). Baseline characteristics differed by regimen [Table 1]. While PDC was similar for both regimens, F/TAF had higher number of dispenses and mean days supplied vs F/TDF; mean days of follow-up were similar [Table 1]. F/TAF users had longer TRD (mean 20.2 vs 8.5 mo, Log-rank p< .001); median TRD was 3.9 mo for F/TDF and not reached for F/TAF [Figure 1]. A higher proportion of PN on F/TDF discontinued (46% vs 24% F/TAF) and switched (26% vs 2% F/TAF) their regimen (both p< .001). After accounting for gender, race, payer, age, high-risk behavior, F/TDF had a higher risk of discontinuation or switch (HR=4.9 CI 3.9-6.2); Black race was also associated with higher risk of discontinuation or switch [Table 2]. Results were similar when considering only discontinuation (censoring at time of switch or loss to follow up). Older age was identified as the primary driver of PDC controlling for other factors [Table 2]. Table 1.Characteristics of PN Individuals Dispensed Oral PrEP After October 2019 and PDC on First PrEP RegimenFigure 1.Time to PrEP Regimen Discontinuation or Switch (TRD, months)Table 2.Risk of First Oral PrEP Regimen Discontinuation or Switch and Characteristics Associated with Higher PDC Conclusion In this study PN adults dispensed F/TAF had greater number of dispenses, mean days supplied, and were less likely to discontinue or switch from F/TAF compared to F/TDF. Older age was the primary driver of increased PDC when considering other factors, including demographics, insurance and regimen. Disclosures Rick A. Elion, MD, Gilead Sciences: Advisor/Consultant|Trio Health: Employee|ViiV: Advisor/Consultant Joshua Gruber, PhD, Gilead Sciences: Employee Janna Radtchenko, MBA, Trio Health: Employee Megan Dunbar, PhD, Gilead Sciences: Employee Kenneth H. Mayer, MD, Gilead: Advisor/Consultant|Merck: Advisor/Consultant|ViiV: Advisor/Consultant Gregory Huhn, MD, MPHTM, Eli Lilly: Advisor/Consultant|Eli Lilly: Grant/Research Support|Gilead: Advisor/Consultant|Gilead: Grant/Research Support|Jannsen: Advisor/Consultant|Jannsen: Grant/Research Support|Merck: Advisor/Consultant|Viiv: Advisor/Consultant|Viiv: Grant/Research Support Karam Mounzer, MD, Epividian: Advisor/Consultant|Gilead Sciences: Advisor/Consultant|Gilead Sciences: Grant/Research Support|Janssen: Advisor/Consultant|Janssen: Grant/Research Support|Merck: Advisor/Consultant|Merck: Grant/Research Support|Trio Health: Advisor/Consultant|ViiV: Advisor/Consultant|ViiV: Grant/Research Support Anthony Mills, MD, Gilead Sciences: Advisor/Consultant|Gilead Sciences: Grant/Research Support|Merck: Advisor/Consultant|Merck: Grant/Research Support|ViiV: Advisor/Consultant|ViiV: Grant/Research Support.