Exceptional collections and D-branes probing toric singularities

We demonstrate that a strongly exceptional collection on a singular toric surface can be used to derive the gauge theory on a stack of D3-branes probing the Calabi-Yau singularity caused by the surface shrinking to zero size. A strongly exceptional collection, i.e., an ordered set of sheaves satisfying special mapping properties, gives a convenient basis of D-branes. We find such collections and analyze the gauge theories for weighted projective spaces, and many of the Y^{p,q} and L^{p,q,r} spaces. In particular, we prove the strong exceptionality for all p in the Y^{p,p-1} case, and similarly for the Y^{p,p-2r} case.Comment: 49 pages, 6 figures; v2 refs added; v3 published versio

C^2/Z_n Fractional branes and Monodromy

We construct geometric representatives for the C^2/Z_n fractional branes in terms of branes wrapping certain exceptional cycles of the resolution. In the process we use large radius and conifold-type monodromies, and also check some of the orbifold quantum symmetries. We find the explicit Seiberg-duality which connects our fractional branes to the ones given by the McKay correspondence. We also comment on the Harvey-Moore BPS algebras.Comment: 34 pages, v1 identical to v2, v3: typos fixed, discussion of Harvey-Moore BPS algebras update

Whole-genome sequencing reveals host factors underlying critical COVID-19

Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2,3,4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease

Improved image quality using monolithic scintillator detectors with dual-sided readout in a whole-body TOF-PET ring: A simulation study

We have recently built and characterized the performance of a monolithic scintillator detector based on a 32 mm × 32 mm × 22 mm LYSO:Ce crystal read out by digital silicon photomultiplier (dSiPM) arrays coupled to the crystal front and back surfaces in a dual-sided readout (DSR) configuration. The detector spatial resolution appeared to be markedly better than that of a detector consisting of the same crystal with conventional back-sided readout (BSR). Here, we aim to evaluate the influence of this difference in the detector spatial response on the quality of reconstructed images, so as to quantify the potential benefit of the DSR approach for high-resolution, whole-body time-of-flight (TOF) positron emission tomography (PET) applications. We perform Monte Carlo simulations of clinical PET systems based on BSR and DSR detectors, using the results of our detector characterization experiments to model the detector spatial responses. We subsequently quantify the improvement in image quality obtained with DSR compared to BSR, using clinically relevant metrics such as the contrast recovery coefficient (CRC) and the area under the localized receiver operating characteristic curve (ALROC). Finally, we compare the results with simulated rings of pixelated detectors with DOI capability. Our results show that the DSR detector produces significantly higher CRC and increased ALROC values than the BSR detector. The comparison with pixelated systems indicates that one would need to choose a crystal size of 3.2 mm with three DOI layers to match the performance of the BSR detector, while a pixel size of 1.3 mm with three DOI layers would be required to get on par with the DSR detector.RST/Applied Radiation & Isotope

Improved image quality using monolithic scintillator detectors with dual-sided readout in a whole-body TOF-PET ring: A simulation study

We have recently built and characterized the performance of a monolithic scintillator detector based on a 32 mm × 32 mm × 22 mm LYSO:Ce crystal read out by digital silicon photomultiplier (dSiPM) arrays coupled to the crystal front and back surfaces in a dual-sided readout (DSR) configuration. The detector spatial resolution appeared to be markedly better than that of a detector consisting of the same crystal with conventional back-sided readout (BSR). Here, we aim to evaluate the influence of this difference in the detector spatial response on the quality of reconstructed images, so as to quantify the potential benefit of the DSR approach for high-resolution, whole-body time-of-flight (TOF) positron emission tomography (PET) applications. We perform Monte Carlo simulations of clinical PET systems based on BSR and DSR detectors, using the results of our detector characterization experiments to model the detector spatial responses. We subsequently quantify the improvement in image quality obtained with DSR compared to BSR, using clinically relevant metrics such as the contrast recovery coefficient (CRC) and the area under the localized receiver operating characteristic curve (ALROC). Finally, we compare the results with simulated rings of pixelated detectors with DOI capability. Our results show that the DSR detector produces significantly higher CRC and increased ALROC values than the BSR detector. The comparison with pixelated systems indicates that one would need to choose a crystal size of 3.2 mm with three DOI layers to match the performance of the BSR detector, while a pixel size of 1.3 mm with three DOI layers would be required to get on par with the DSR detector.RST/Applied Radiation & Isotope

Restorative Justice and College Student Misconduct

This article reports the findings of a restorative justice program to address student disciplinary problems at Skidmore College. Based on the model of “Community Reparative Boards” developed by the Vermont Department of Corrections for probation cases, the Skidmore Integrity Board is representative board of students, faculty, and staff. The article describes the nature and purpose of the board and reports findings from three recent years of board activity. Copyright Springer Science + Business Media, Inc. 2005organizational change, student misconduct, college judicial board, restorative justice,

Evaluation of Text Clustering Algorithms with N-Gram-Based Document Fingerprints

Abstract. This paper presents a new approach designed to reduce the computational load of the existing clustering algorithms by trimming down the documents size using fingerprinting methods. Thorough evaluation was performed over three different collections and considering four different metrics. The presented approach to document clustering achieved good values of effectiveness with considerable save in memory space and computation time.

PHYSICAL ACTIVITY MEASUREMENT VALIDITY OF MOTION SENSOR TECHNOLOGIES IN LABORATORY SETTINGS

PHYSICAL ACTIVITY MEASUREMENT VALIDITY OF MOTION SENSOR TECHNOLOGIES IN LABORATORY SETTINGS K. Taylor, D.R. Paul, A.K. Martin, S.P. Beitey, S.L. Croston, G. Goc Karp, C.A. Vella FACSM, D. Rosslerova, K.J. Young, E.M. Drake, P.W. Scruggs University of Idaho, Moscow, ID The Institute of Medicine recommends that physical education (PE) engage students in moderate to vigorous physical activity (MVPA) during class; however, there is a paucity of research on practical physical activity (PA) assessment technologies. Purpose: To examine the agreement between simple and complex PA assessment technologies under controlled indoor and outdoor conditions. Methods: Participants (N = 33, 12.61±1.24yr) wore motion sensors (SW200, W4L MVPa 3D, FitStep Pro, GeoPal, MOVband, NL1000, and GT3X+) while walking and jogging on a treadmill and outdoors. Participants walked and jogged on a treadmill (0% grade, 2 min at speeds of 80a, 107b, 134c, and 161dm/min), and 250m outdoor course (self-selected paces). Criterion and predictor measures were observed steps and walk or jog time, and steps and MVPA time, respectively. Absolute-value percent error scores (APES, [[|criterion - predictor|] / criterion] x 100) were computed for each predictor measure. Mean APES were compared against a ≤ 10% (±95% CI) criterion and analyzed by one-way ANOVA (p≤0.05) and Bonferroni post hoc tests. Results: Treadmill APES for steps were not significantly different across all speeds and were ≤ 10% of criterion (lowest APES, 1.69±0.57%[GeoPal]a, 0.86±0.39%[SW200]b, 0.75±0.46%[SW200]c, 0.69±0.53%[SW200]d), except for the MOVband (p \u3c 0.05, 12.25±3.24d). APES for the outdoor walking (0.82±0.21%[MVPa] to 3.85±1.92%[GeoPal]) and jogging (2.04±2.05%[SW200] to 7.12±2.75%[MVPa]) conditions were similar (p \u3e 0.05) and ≤ 10%, except for MOVband (p \u3c 0.05, 10.74±3.67 to 40.34±4.51%). At all treadmill speeds except 80m/min, APES for MVPA were ≤10% of criterion. The NL1000 had the only APES (2.36±1.29%) ≤ 10% at 80m/min and that was significantly different than all others (p\u3c0.05). At 107 and 134m/min, APES were similar across instruments (p \u3e 0.23) and all APES at 161m/min were similar (p \u3e 0.99), except for MVPa (3.77±2.91%, p \u3c 0.03). Two APES were similar (p \u3e 0.99) and ≤ 10% for the outdoor walk (1.84±1.48%[GT3X+], 6.93±5.00%[NL1000]), and two APES (GeoPals) were \u3e 10% for the outdoor jog and the remaining were similar (p \u3e 0.99, 0.49±0.12[GT3X+] to 5.35±2.21%[MVPa]). Conclusions: Results from this study indicate there are multiple practical PA instruments that can validly measure steps and MVPA