Colorful and Quantitative Variations of Krasnosselsky's Theorem

Krasnosselsky's art gallery theorem gives a combinatorial characterization of star-shaped sets in Euclidean spaces, similar to Helly's characterization of finite families of convex sets with non-empty intersection. We study colorful and quantitative variations of Krasnosselsky's result. In particular, we are interested in conditions on a set $K$ that guarantee there exists a measurably large set $K'$ such that every point in $K'$ can see every point in $K$. We prove results guaranteeing the existence of $K'$ with large volume or large diameter.Comment: 12 pages, 4 Figure

How Peer Support Specialists Uniquely Initiate and Build Connection with Young People Experiencing Homelessness

Young people experiencing homelessness are often apprehensive to engage in conventional service systems due to prior mistreatment by providers and others in their lives, as well as stigma associated with accessing services. Even when relationships between service providers and young people are initiated, they often end prematurely. Mutual aid, or peer-to-peer support, has a long and promising history within the mental health field, yet has received little empirical attention in work with young people experiencing homelessness. The present study used participatory qualitative methods to understand how peers uniquely initiate and build connection with young people experiencing homelessness. Through interviews and journaling with peer support specialists and program staff, this study found that peers initiate relationships with young people by becoming familiar faces in youth spaces, identifying themselves as peers, then formalizing relationships with young people. Peers build connection by showing they are on the “same side of the glass” as young people, establishing autonomy and availability over a preset agenda, and creating containers acceptable for failure. Peers, their supervisors, and organizations building mutual aid programs may consider these findings when working to build programs which flexibly and authentically engage young people experiencing homelessness in meaningful relationships

Anthropometric profiles of elite athletes

Quantifying body composition is central to monitoring performance and training in athletes, however limited sport-specific anthropometric reference data, assessed and reported in a standardised manner, is available. This study provides anthropometric profiles in elite male athletes from different sports. Elite male athletes (n = 73) from National squads of boxing (n = 10), cricket (n = 21), swimming (n = 23), hockey (n = 10) and eventing (n = 9) were assessed for body mass, height, eight skinfolds (triceps, subscapular, biceps, iliac crest, supraspinal, abdominal, thigh and medial calf), body circumferences (arm, waist, hip, thigh and calf) and muscle circumferences (arm, thigh, calf) using ISAK standardised guidelines. For all athletes, large variability exists for measures of skinfold thickness at each skinfold site. Swimming (64.6 ± 16.1 mm) and boxing (63.5 ± 16.1 mm) were similar for the sum of eight skinfolds (Σ8SKF) but swimming had lower Σ8SKF compared to cricket (86.1 ± 21.3 mm; p = .011) and eventing (89.9 ± 30.7 mm; p = .028). Hockey (81.9 ± 26.3 mm) and eventing had the most varied Σ8SKF. Thigh body (p=.006) and muscle circumferences (p = .005) were significantly reduced in boxing compared to hockey. No differences were seen between sports for arm (p = .346; ES = .06) and calf (p = .382; ES = .06) muscle circumferences. The anthropometric profiles for elite athletes from various sports during pre-season training will be a useful resource for sports professionals when monitoring and interpreting body composition data. Large variation exists in anthropometric profiles between the different athletes and different sports, highlighting the necessity to have sport-specific normative ranges available to allow optimal monitoring of individual athletes particularly varying across sports as well as age, training status and position

Phylogenomic Analysis Reveals Dynamic Evolutionary History of the Drosophila Heterochromatin Protein 1 (HP1) Gene Family

Heterochromatin is the gene-poor, satellite-rich eukaryotic genome compartment that supports many essential cellular processes. The functional diversity of proteins that bind and often epigenetically define heterochromatic DNA sequence reflects the diverse functions supported by this enigmatic genome compartment. Moreover, heterogeneous signatures of selection at chromosomal proteins often mirror the heterogeneity of evolutionary forces that act on heterochromatic DNA. To identify new such surrogates for dissecting heterochromatin function and evolution, we conducted a comprehensive phylogenomic analysis of the Heterochromatin Protein 1 gene family across 40 million years of Drosophila evolution. Our study expands this gene family from 5 genes to at least 26 genes, including several uncharacterized genes in Drosophila melanogaster. The 21 newly defined HP1s introduce unprecedented structural diversity, lineage-restriction, and germline-biased expression patterns into the HP1 family. We find little evidence of positive selection at these HP1 genes in both population genetic and molecular evolution analyses. Instead, we find that dynamic evolution occurs via prolific gene gains and losses. Despite this dynamic gene turnover, the number of HP1 genes is relatively constant across species. We propose that karyotype evolution drives at least some HP1 gene turnover. For example, the loss of the male germline-restricted HP1E in the obscura group coincides with one episode of dramatic karyotypic evolution, including the gain of a neo-Y in this lineage. This expanded compendium of ovary- and testis-restricted HP1 genes revealed by our study, together with correlated gain/loss dynamics and chromosome fission/fusion events, will guide functional analyses of novel roles supported by germline chromatin

First-Year Medical Student Feedback Regarding the Addition of Online Learning Modules to the Curriculum

Introduction: The first year of the medical student curriculum at the John A. Burns School of Medicine consists of four blocks. The first block–MD1: Health and Illness–is a 9-week introduction to Problem-Based Learning (PBL) and foundational sciences. In response to the COVID-19 pandemic, MD1 introduced online modules (pre-recorded lectures assigned outside of scheduled lecture times) for fall 2020. While student ratings of MD1 were mostly favorable, students expressed specific concerns regarding online modules in MD1 mid-course evaluations. Comments included, “we feel overwhelmed by the length and content in addition to the scheduled lectures we already have” and “we were not huge fans of the online modules”. Additionally, “Q&A and review sessions” corresponding with each online module were scheduled in the second half of MD1 to provide dedicated time for students to meet with instructors. The formats of these sessions were left to the discretion of the instructor, resulting in high variability. Students were surveyed to elaborate their thoughts towards online modules and review sessions. Although this project was done in the context of MD1 online modules, we hope to extend the recommendations to all lectures in the pre-clerkship units. Objectives: The purpose of this study was to identify strengths, areas of improvement, and suggestions regarding online modules assigned in MD1. Methods: A quality improvement online survey was administered in October 2020 to 77 students in the JABSOM Class of 2024. Quantitative and qualitative questions were newly developed based on feedback from the MD1 mid-course evaluations and addressed areas including preferred presentation style, lecture reviews, effective characteristics, and overall sentiment of the online modules. Patterns among the qualitative responses were identified by the authors to recognize student preferences. Results: The survey was completed by 63 (81.8%) students. Of note, 100% of enrolled students earned passing scores on MD1 end-course exams. Students rated their overall feelings about the online modules 5.9±1.5 out of 10. The majority (55.6%) of students preferred practice questions provided and discussed in pre-recorded lectures. Student comments suggested the most effective review session formats were based on instructors’ practice questions or overviews of key lecture slides. Respondents also reported the most effective lectures had exam-like practice questions with explanations and direct connections to MD1 PBL cases. Additionally, respondents recommended scheduling in specific time blocks to watch pre-recorded lectures during school day hours, to more closely mimic live, in-person lectures. Discussion: The prevalence of online learning in medical school curricula has increased, perhaps due to the COVID-19 pandemic. We surveyed the JABSOM Class of 2024 about their MD1 online learning experience and consolidated feedback to the following recommendations. (1) Regarding content, we recommend lecturers (a) relate the material to PBL cases and (b) discuss clinical examples. (2) Regarding practice questions, we recommend lecturers prepare and discuss practice questions during their lectures. (3) Regarding review sessions, we recommend lecturers prepare a summary of both (a) testable, key concepts and (b) additional practice questions. We propose these changes and practices can lead to improved learner satisfaction while maintaining the high standard of learner performance outcomes that faculty and students share. Target Audience: Students and educators, JABSOM Office of Medical Educatio

Comparative analysis of anti-polyglutamine Fab crystals grown on Earth and in microgravity

Huntington's disease is one of nine neurodegenerative diseases caused by a polyglutamine (polyQ)-repeat expansion. An anti-polyQ antigen-binding fragment, MW1 Fab, was crystallized both on Earth and on the International Space Station, a microgravity environment where convection is limited. Once the crystals returned to Earth, the number, size and morphology of all crystals were recorded, and X-ray data were collected from representative crystals. The results generally agreed with previous microgravity crystallization studies. On average, microgravity-grown crystals were 20% larger than control crystals grown on Earth, and microgravity-grown crystals had a slightly improved mosaicity (decreased by 0.03°) and diffraction resolution (decreased by 0.2 Å) compared with control crystals grown on Earth. However, the highest resolution and lowest mosaicity crystals were formed on Earth, and the highest-quality crystal overall was formed on Earth after return from microgravity

The type III secretion system effector SeoC of salmonella enterica subsp. salamae and S. enterica subsp. arizonae ADP-Ribosylates Src and inhibits opsonophagocytosis

Salmonella species utilize type III secretion systems (T3SSs) to translocate effectors into the cytosol of mammalian host cells, subverting cell signaling and facilitating the onset of gastroenteritis. In this study, we compared a draft genome assembly of Salmonella enterica subsp. salamae strain 3588/07 against the genomes of S. enterica subsp. enterica serovar Typhimurium strain LT2 and Salmonella bongori strain 12419. S. enterica subsp. salamae encodes the Salmonella pathogenicity island 1 (SPI-1), SPI-2, and the locus of enterocyte effacement (LEE) T3SSs. Though several key S Typhimurium effector genes are missing (e.g., avrA, sopB, and sseL), S. enterica subsp. salamae invades HeLa cells and contains homologues of S. bongori sboK and sboC, which we named seoC SboC and SeoC are homologues of EspJ from enteropathogenic and enterohemorrhagic Escherichia coli (EPEC and EHEC, respectively), which inhibit Src kinase-dependent phagocytosis by ADP-ribosylation. By screening 73 clinical and environmental Salmonella isolates, we identified EspJ homologues in S. bongori, S. enterica subsp. salamae, and Salmonella enterica subsp. arizonae The β-lactamase TEM-1 reporter system showed that SeoC is translocated by the SPI-1 T3SS. All the Salmonella SeoC/SboC homologues ADP-ribosylate Src E310 in vitro Ectopic expression of SeoC/SboC inhibited phagocytosis of IgG-opsonized beads into Cos-7 cells stably expressing green fluorescent protein (GFP)-FcγRIIa. Concurrently, S. enterica subsp. salamae infection of J774.A1 macrophages inhibited phagocytosis of beads, in a seoC-dependent manner. These results show that S. bongori, S. enterica subsp. salamae, and S. enterica subsp. arizonae share features of the infection strategy of extracellular pathogens EPEC and EHEC and shed light on the complexities of the T3SS effector repertoires of Enterobacteriaceae

Association of Amygdala Development with Different Forms of Anxiety in Autism Spectrum Disorder

Background: The amygdala is widely implicated in both anxiety and autism spectrum disorder. However, no studies have investigated the relationship between co-occurring anxiety and longitudinal amygdala development in autism. Here, the authors characterize amygdala development across childhood in autistic children with and without traditional DSM forms of anxiety and anxieties distinctly related to autism. Methods: Longitudinal MRI scans were acquired at up to four timepoints for 71 autistic and 55 typically developing (TD) children (∼2.5-12 years, 411 timepoints). Traditional DSM anxiety and anxieties distinctly related to autism were assessed at study Time 4 (∼8-12 years) using a diagnostic interview tailored to autism: The Anxiety Disorders Interview Schedule-IV with the Autism Spectrum Addendum. Mixed effects models were used to test group differences at study Time 1 (3.18 years), Time 4 (11.36 years), and developmental differences (age-by-group interactions) in right and left amygdala volume between autistic children with and without DSM or autism distinct anxieties, and TD. Results: Autistic children with DSM anxiety had significantly larger right amygdala volumes compared to TD at both study Time 1 (5.10% increase) and Time 4 (6.11% increase). Autistic children with autism distinct anxieties had significantly slower right amygdala growth compared to TD, autism-no anxiety, and autism-DSM anxiety groups and smaller right amygdala volumes at Time 4 compared to the autism-no anxiety (-8.13% decrease) and autism-DSM anxiety (-12.05% decrease) groups. Conclusions: Disparate amygdala volumes and developmental trajectories between DSM and autism distinct forms of anxiety suggest different biological underpinnings for these common, co-occurring conditions in autism

Spider monkeys rule the roost: Ateline sleeping sites influence rainforest heterogeneity

: The sleeping site behavior of Ateline primates has been of interest since the 1980s, yet limited focus has been given to their influence upon other rainforest species. Here, we use a combination of arboreal and terrestrial camera traps, and dung beetle pitfall traps, to characterize spider monkey sleeping site use and quantify the impact of their associated latrines on terrestrial vertebrate and dung beetle activity. We also characterize the physical characteristics of the sleeping sites and the floristic and soil composition of latrines beneath them. Spider monkey activity at sleeping sites peaked at dawn and dusk and group composition varied by sex of the adults detected. The habitat-use of terrestrial fauna (vertebrates and dung beetles) differed between latrine sites and non-latrine controls, underpinned by species-specific changes in the relative abundance of several seed-dispersing species (such as paca and great curassow). Seedling density was higher in latrines than in non-latrine controls. Although most soil properties were similar between latrines and controls, potassium and manganese concentrations were different. These results suggest that spider monkey sleeping site fidelity leads to a hotspot of ecological activity in latrines and downstream impacts on rainforest floristic composition and diversity

Reduced-Intensity/Reduced-Toxicity Conditioning Approaches Are Tolerated in XIAP Deficiency but Patients Fare Poorly with Acute GVHD

X-linked inhibitor of apoptosis (XIAP) deficiency is an inherited primary immunodeficiency characterized by chronic inflammasome overactivity and associated with hemophagocytic lymphohistiocytosis (HLH) and inflammatory bowel disease (IBD). Allogeneic hematopoietic cell transplantation (HCT) with fully myeloablative conditioning may be curative but has been associated with poor outcomes. Reports of reduced-intensity conditioning (RIC) and reduced-toxicity conditioning (RTC) regimens suggest these approaches are well tolerated, but outcomes are not well established. Retrospective data were collected from an international cohort of 40 patients with XIAP deficiency who underwent HCT with RIC or RTC. Thirty-three (83%) patients had a history of HLH, and thirteen (33%) patients had IBD. Median age at HCT was 6.5 years. Grafts were from HLA-matched (n = 30, 75%) and HLA-mismatched (n = 10, 25%) donors. There were no cases of primary graft failure. Two (5%) patients experienced secondary graft failure, and three (8%) patients ultimately received a second HCT. Nine (23%) patients developed grade II-IV acute GVHD, and 3 (8%) developed extensive chronic GVHD. The estimated 2-year overall and event-free survival rates were 74% (CI 55-86%) and 64% (CI 46-77%), respectively. Recipient and donor HLA mismatch and grade II-IV acute GVHD were negatively associated with survival on multivariate analysis with hazard ratios of 5.8 (CI 1.5-23.3, p = 0.01) and 8.2 (CI 2.1-32.7, p < 0.01), respectively. These data suggest that XIAP patients tolerate RIC and RTC with survival rates similar to HCT of other genetic HLH disorders. Every effort should be made to prevent acute GVHD in XIAP-deficient patients who undergo allogeneic HCT