Applications of Partial Supersymmetry

I examine quantum mechanical Hamiltonians with partial supersymmetry, and explore two main applications. First, I analyze a theory with a logarithmic spectrum, and show how to use partial supersymmetry to reveal the underlying structure of this theory. This method reveals an intriguing equivalence between two formulations of this theory, one of which is one-dimensional, and the other of which is infinite-dimensional. Second, I demonstrate the use of partial supersymmetry as a tool to obtain the asymptotic energy levels in non-relativistic quantum mechanics in an exceptionally easy way. In the end, I discuss possible extensions of this work, including the possible connections between partial supersymmetry and renormalization group arguments.Comment: 11 pages, harvmac, no figures; typo corrected in identifying info on title pag

A BPS Interpretation of Shape Invariance

We show that shape invariance appears when a quantum mechanical model is invariant under a centrally extended superalgebra endowed with an additional symmetry generator, which we dub the shift operator. The familiar mathematical and physical results of shape invariance then arise from the BPS structure associated with this shift operator. The shift operator also ensures that there is a one-to-one correspondence between the energy levels of such a model and the energies of the BPS-saturating states. These findings thus provide a more comprehensive algebraic setting for understanding shape invariance.Comment: 15 pages, 2 figures, LaTe

Properties of Ridges in Elastic Membranes

When a thin elastic sheet is confined to a region much smaller than its size the morphology of the resulting crumpled membrane is a network of straight ridges or folds that meet at sharp vertices. A virial theorem predicts the ratio of the total bending and stretching energies of a ridge. Small strains and curvatures persist far away from the ridge. We discuss several kinds of perturbations that distinguish a ridge in a crumpled sheet from an isolated ridge studied earlier (A. E. Lobkovsky, Phys. Rev. E. 53 3750 (1996)). Linear response as well as buckling properties are investigated. We find that quite generally, the energy of a ridge can change by no more than a finite fraction before it buckles.Comment: 13 pages, RevTeX, acknowledgement adde

Johnson-Kendall-Roberts theory applied to living cells

Johnson-Kendall-Roberts (JKR) theory is an accurate model for strong adhesion energies of soft slightly deformable material. Little is known about the validity of this theory on complex systems such as living cells. We have addressed this problem using a depletion controlled cell adhesion and measured the force necessary to separate the cells with a micropipette technique. We show that the cytoskeleton can provide the cells with a 3D structure that is sufficiently elastic and has a sufficiently low deformability for JKR theory to be valid. When the cytoskeleton is disrupted, JKR theory is no longer applicable

Analysis of state laws on informed consent for clinical genetic testing in the era of genomic sequencing

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143694/1/ajmgc31608_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/143694/2/ajmgc31608.pd

Racial and ethnic disparities in pelvic floor disorder awareness

Objectives: Pelvic floor disorders (PFD) affect the quality of life for many women and can be a significant cause of distress. With the United States’ aging population, PFD are becoming increasingly prevalent. Previous population based studies identified both differences in prevalence and baseline knowledge of PFD by race and ethnicity. These prior studies assessing PFD knowledge were limited to single geographical areas or institutions. We aim to conduct a multicenter study across the United States to better understand the baseline knowledge and perceptions of PFD and its variance across different races and ethnicities. Our goal is to provide data that will help deliver culturally competent information to patients. Materials and Methods: This was a multicenter cross-sectional study involving six sites. Upon initial presentation to a urogynecology clinic, patients were evaluated with the Prolapse and Incontinence Knowledge Questionnaire along with additional questions aimed to assess differences in PFD descriptive language, barriers to care, and attitude towards PFD. Surveys were distributed at participating institutions from October 2019 to February 2021. Statistical analyses were performed with Fisher\u27s exact test and Chi-square test, using p \u3c0.05 for statistical significance. Results: A total of 287 women completed the survey, with 27 excluded due to omission of race and or ethnicity responses. Respondents identified their ethnicity as Hispanic (21.8%) and race as White (70.5%), African American (AA) (19.2%), and Other Women of Color (OWOC) (10.3%). Overall, the mean percent correct for the urinary incontinence (UI) and pelvic organ prolapse (POP) sub-scores were 61.2 ± 28.2 and 60.5 ± 28.2, respectively. AA and OWOC had lower scores compared to White respondents in both UI (AA 60.7 ± 30.1; OWOC 46.8 ± 31.2; W 63.5 ± 26.5; p = 0.018) and POP (AA 55.5 ±30.1; OWOC 48.9 ± 31.0; W 64 ± 26.2; p = 0.011). Hispanic women scored lower in both UI (43.9 ± 29.8 vs 66.5 ± 25.3, p \u3c0.001) and POP (46.2 ± 28.4 vs 66.5 ± 25.3, p\u3c0.001) when compared to non-Hispanic respondents. AA and OWOC had decreased knowledge of POP language compared to White respondents (32.3 ± 30.8 % correct vs 35.4 ± 33.6 % correct vs 50.4 ± 32.9 % correct, p \u3c0.001). This was similar for Hispanic compared to non-Hispanic respondents (33.3 ± 31.2 % correct vs 40.1 ± 32.5 % correct, p\u3c0.001). Responses to UI and POP misconception questions were not different by race or ethnicity. Conclusion: This is the first multicenter, cross-sectional survey of a diverse patient population assessing knowledge and perception of PFD. We observed differences between baseline knowledge and language proficiency of PFD amongst AA, White, and OWOC, as well as between Hispanic and non-Hispanic women. This suggests the presence of racial disparities in women pursuing urogynecologic care and highlights the importance of delivering culturally sensitive information to educate women of diverse backgrounds

Expanding the Description of Spaceflight Effects beyond Bone Mineral Density [BMD]: Trabecular Bone Score [TBS] in ISS Astronauts

Dual-energy x-ray absorptiometry [DXA] is the widely-applied bone densitometry method used to diagnose osteoporosis in a terrestrial population known to be at risk for age-related bone loss. This medical test, which measures areal bone mineral density [aBMD] of clinically-relevant skeletal sites (e.g., hip and spine), helps the clinician to identify which persons, among postmenopausal women and men older than 50 years, are at high risk for low trauma or fragility fractures and might require an intervention. The most recognized osteoporotic fragility fracture is the vertebral compression fracture which can lead to kyphosis or hunched backs typically seen in the elderly. DXA measurement of BMD however is recognized to be insufficient as a sole index for assessing fracture risk. DXA's limitation may be related to its inability to monitor changes in structural parameters, such as trabecular vs. cortical bone volumes, bone geometry or trabecular microarchitecture. Hence, in order to understand risks to human health and performance due to space exposure, NASA needs to expand its measurements of bone to include other contributors to skeletal integrity. To this aim, the Bone and Mineral Lab conducted a pilot study for a novel measurement of bone microarchitecture that can be obtained by retrospective analysis of DXA scans. Trabecular Bone Score (TBS) assesses changes to trabecular microarchitecture by measuring the grey color "texture" information extracted from DXA images of the lumbar spine. An analysis of TBS in 51 ISS astronauts was conducted to assess if TBS could detect 1) an effect of spaceflight and 2) a response to countermeasures independent of DXA BMD. In addition, changes in trunk body lean tissue mass and in trunk body fat tissue mass were also evaluated to explore an association between body composition, as impacted by ARED exercise, and bone microarchitecture. The pilot analysis of 51 astronaut scans of the lumbar spine suggests that, following an ISS mission, DXA BMD and TBS are detecting different effects of ARED exercise and of ARED + Bisphosphonate on the lumbar spine of astronauts. There is emerging evidence associating reduced TBS with terrestrial metabolic bone disorders where a TBS 1.350 is associated with "normal." However, it is not possible to conclude how the spaceflight-induced changes in TBS increase risk for vertebral fractures in the astronaut or if changes in body composition of the trunk region could be an indirect method of assessing exercise effect on bone microarchitecture. More importantly, this pilot analysis demonstrates a new, minimal risk approach for monitoring changes to vertebral bone microarchitecture. This method could help assess the combined skeletal effects of spaceflight with the effects of aging in the astronaut after return to Earth

ABO antigen and secretor statuses are not associated with gut microbiota composition in 1,500 twins

Background: Host genetics is one of several factors known to shape human gut microbiome composition, however, the physiological processes underlying the heritability are largely unknown. Inter-individual differences in host factors secreted into the gut lumen may lead to variation in microbiome composition. One such factor is the ABO antigen. This molecule is not only expressed on the surface of red blood cells, but is also secreted from mucosal surfaces in individuals containing an intact FUT2 gene (secretors). Previous studies report differences in microbiome composition across ABO and secretor genotypes. However, due to methodological limitations, the specific bacterial taxa involved remain unknown.Results: Here, we sought to determine the relationship of the microbiota to ABO blood group and secretor status in a large panel of 1503 individuals from a cohort of twins from the United Kingdom. Contrary to previous reports, robust associations between either ABO or secretor phenotypes and gut microbiome composition were not detected. Overall community structure, diversity, and the relative abundances of individual taxa were not significantly associated with ABO or secretor status. Additionally, joint-modeling approaches were unsuccessful in identifying combinations of taxa that were predictive of ABO or secretor status.Conclusions: Despite previous reports, the taxonomic composition of the microbiota does not appear to be strongly associated with ABO or secretor status in 1503 individuals from the United Kingdom. These results highlight the importance of replicating microbiome-associated traits in large, well-powered cohorts to ensure results are robust

Dietary influence on systolic and diastolic blood pressure in the TwinsUK cohort

Nutrition plays a key role in blood pressure (BP) regulation. Here, we examine associations between nutrient intakes and BP in a large predominantly female population-based cohort. We assessed the correlation between 45 nutrients (from food frequency questionnaires) and systolic BP/diastolic BP (SBP/DBP) in 3889 individuals from TwinsUK not on hypertensive treatments and replicated in an independent subset of monozygotic twins discordant for nutrient intake (17–242 pairs). Results from both analyses were meta-analysed. For significant nutrients, we calculated heritability using structural equation modelling. We identified and replicated 15 nutrients associated with SBP, 9 also being associated with DBP, adjusting for covariates and multiple testing. 14 of those had a heritable component (h2: 27.1–57.6%). Strong associations with SBP were observed for riboflavin (Beta(SE) = −1.49(0.38), P = 1.00 × 10−4) and tryptophan (−0.31(0.01), P = 5 × 10−4), while with DBP for alcohol (0.05(0.07), P = 1.00 × 10−4) and lactose (−0.05(0.0), P = 1.3 × 10−3). Two multivariable nutrient scores, combining independently SBP/DBP-associated nutrients, explained 22% of the variance in SBP and 13.6% of the variance in DBP. Moreover, bivariate heritability analysis suggested that nutrients and BP share some genetic influences. We confirm current understanding and extend the panel of dietary nutrients implicated in BP regulation underscoring the value of nutrient focused dietary research in preventing and managing hypertension

Engagement of Fusiform Cortex and Disengagement of Lateral Occipital Cortex in the Acquisition of Radiological Expertise

The human visual pathways that are specialized for object recognition stretch from lateral occipital cortex (LO) to the ventral surface of the temporal lobe, including the fusiform gyrus. Plasticity in these pathways supports the acquisition of visual expertise, but precisely how training affects the different regions remains unclear. We used functional magnetic resonance imaging to measure neural activity in both LO and the fusiform gyrus in radiologists as they detected abnormalities in chest radiographs. Activity in the right fusiform face area (FFA) correlated with visual expertise, measured as behavioral performance during scanning. In contrast, activity in left LO correlated negatively with expertise, and the amount of LO that responded to radiographs was smaller in experts than in novices. Activity in the FFA and LO correlated negatively in experts, whereas in novices, the 2 regions showed no stable relationship. Together, these results suggest that the FFA becomes more engaged and left LO less engaged in interpreting radiographic images over the course of training. Achieving expert visual performance may involve suppressing existing neural representations while simultaneously developing others