55 research outputs found
BRST Cohomology is Lie Algebroid Cohomology
In this paper we demonstrate that the exterior algebra of an Atiyah Lie
algebroid generalizes the familiar notions of the physicist's BRST complex. To
reach this conclusion, we develop a general picture of Lie algebroid morphisms
as commutative diagrams between algebroids preserving the geometric structure
encoded in their brackets. We illustrate that a necessary and sufficient
condition for such a diagram to define a morphism is that the two algebroids
possess gauge-equivalent connections. This observation indicates that the set
of Lie algebroid morphisms should be regarded as equivalent to the set of local
diffeomorphisms and gauge transformations. Moreover, a Lie algebroid morphism
being a chain map in the exterior algebra sense ensures that morphic algebroids
are cohomologically equivalent. The Atiyah Lie algebroids derived from
principal bundles with common base manifolds and structure groups may therefore
be divided into equivalence classes of morphic algebroids. Each equivalence
class possesses a representative which we refer to as the trivialized Lie
algebroid, and we show that the exterior algebra of the trivialized algebroid
gives rise to the BRST complex. We conclude by illustrating the usefulness of
Lie algebroid cohomology in computing quantum anomalies. In particular, we pay
close attention to the fact that the geometric intuition afforded by the Lie
algebroid (which was absent in the naive BRST complex) provides hints of a
deeper picture that simultaneously geometrizes the consistent and covariant
forms of the anomaly. In the algebroid construction, the difference between the
consistent and covariant anomalies is simply a different choice of basis.Comment: 24 pages, 1 figure, LaTe
Compassion, Discrimination, and Prosocial Behaviors: Young Diasporic Chinese During the COVID-19 Pandemic
The coronavirus disease 2019 (COVID-19) pandemic has fueled anti-Asian, especially anti-Chinese sentiments worldwide, which may negatively impact diasporic Chinese youths\u27 adjustment and prosocial development. This study examined the association between compassion, discrimination and prosocial behaviors in diasporic Chinese youths during the COVID-19 pandemic. 360 participants participated and completed the multi-country, cross-sectional, web-based survey between April 22 and May 9, 2020, the escalating stage of the pandemic. This study found compassion as prosocial behaviors\u27 proximal predictor, while discrimination independently predicted participation in volunteering, and could potentially enhance the association between compassion and charitable giving. These findings suggest that prosociality among young people is sensitive to social context, and that racial discrimination should be considered in future prosocial studies involving young members of ethnic and racial minorities
Mutations in sphingosine-1-phosphate lyase cause nephrosis with ichthyosis and adrenal insufficiency
Steroid-resistant nephrotic syndrome (SRNS) causes 15% of chronic kidney disease cases. A mutation in 1 of over 40 monogenic genes can be detected in approximately 30% of individuals with SRNS whose symptoms manifest before 25 years of age. However, in many patients, the genetic etiology remains unknown. Here, we have performed whole exome sequencing to identify recessive causes of SRNS. In 7 families with SRNS and facultative ichthyosis, adrenal insufficiency, immunodeficiency, and neurological defects, we identified 9 different recessive mutations in SGPL1, which encodes sphingosine-1-phosphate (S1P) lyase. All mutations resulted in reduced or absent SGPL1 protein and/or enzyme activity. Overexpression of cDNA representing SGPL1 mutations resulted in subcellular mislocalization of SGPL1. Furthermore, expression of WT human SGPL1 rescued growth of SGPL1-deficient dpl1. yeast strains, whereas expression of disease-associated variants did not. Immunofluorescence revealed SGPL1 expression in mouse podocytes and mesangial cells. Knockdown of Sgpl1 in rat mesangial cells inhibited cell migration, which was partially rescued by VPC23109, an S1P receptor antagonist. In Drosophila, Sply mutants, which lack SGPL1, displayed a phenotype reminiscent of nephrotic syndrome in nephrocytes. WT Sply, but not the disease-associated variants, rescued this phenotype. Together, these results indicate that SGPL1 mutations cause a syndromic form of SRNS
Genome-Wide Association Studies in an Isolated Founder Population from the Pacific Island of Kosrae
It has been argued that the limited genetic diversity and reduced allelic heterogeneity observed in isolated founder populations facilitates discovery of loci contributing to both Mendelian and complex disease. A strong founder effect, severe isolation, and substantial inbreeding have dramatically reduced genetic diversity in natives from the island of Kosrae, Federated States of Micronesia, who exhibit a high prevalence of obesity and other metabolic disorders. We hypothesized that genetic drift and possibly natural selection on Kosrae might have increased the frequency of previously rare genetic variants with relatively large effects, making these alleles readily detectable in genome-wide association analysis. However, mapping in large, inbred cohorts introduces analytic challenges, as extensive relatedness between subjects violates the assumptions of independence upon which traditional association test statistics are based. We performed genome-wide association analysis for 15 quantitative traits in 2,906 members of the Kosrae population, using novel approaches to manage the extreme relatedness in the sample. As positive controls, we observe association to known loci for plasma cholesterol, triglycerides, and C-reactive protein and to a compelling candidate loci for thyroid stimulating hormone and fasting plasma glucose. We show that our study is well powered to detect common alleles explaining ≥5% phenotypic variance. However, no such large effects were observed with genome-wide significance, arguing that even in such a severely inbred population, common alleles typically have modest effects. Finally, we show that a majority of common variants discovered in Caucasians have indistinguishable effect sizes on Kosrae, despite the major differences in population genetics and environment
Mutations in KEOPS-Complex Genes Cause Nephrotic Syndrome with Primary Microcephaly
Galloway-Mowat syndrome (GAMOS) is an autosomal-recessive disease characterized by the combination of early-onset nephrotic syndrome (SRNS) and microcephaly with brain anomalies. Here we identified recessive mutations in OSGEP, TP53RK, TPRKB, and LAGE3, genes encoding the four subunits of the KEOPS complex, in 37 individuals from 32 families with GAMOS. CRISPR-Cas9 knockout in zebrafish and mice recapitulated the human phenotype of primary microcephaly and resulted in early lethality. Knockdown of OSGEP, TP53RK, or TPRKB inhibited cell proliferation, which human mutations did not rescue. Furthermore, knockdown of these genes impaired protein translation, caused endoplasmic reticulum stress, activated DNA-damage-response signaling, and ultimately induced apoptosis. Knockdown of OSGEP or TP53RK induced defects in the actin cytoskeleton and decreased the migration rate of human podocytes, an established intermediate phenotype of SRNS. We thus identified four new monogenic causes of GAMOS, describe a link between KEOPS function and human disease, and delineate potential pathogenic mechanisms
The effect of pension wealth on private savings. Results from an extended life cycle model
An extended life cycle model is used to investigate how variation in the level of expected pensions influences non-pension wealth accumulation. We try to explain why the offset effects between pension wealth and private savings are not one to one by accounting for different risks and market imperfections, which includes uninsured risk on earnings, mortality risk, borrowing constraints and bequest motive. The model is calibrated on Norwegian household data from 1992 to 2005. Based on the calibrated model, simulations are performed to explore consequences of introducing these factors. The result shows that by simply accounting these risks and constraints, we can explain most of the departure between empirical findings and theoretical prediction.publishedVersio
Research on Designing an Industrial Product-Service System with Uncertain Customer Demands
The industrial product-service system (iPSS) is a kind of system engineering methodology, integration scheme, and business model to realize service value by adding intangible services in the whole life cycle. However, the design of the system involves many difficulties such as uncertain customer demands, strong subjectivity of the experience design, and long debugging times. Methods for solving upper problems are therefore essential. This paper presents a design model that integrates an improved affinity propagation (AP) clustering algorithm, quality function development (QFD), and axiomatic design (AD). The entire process of designing an iPSS can be split into three steps. First, uncertain customer demands is determined and standardized. Second, the functions of the product-service system are investigated. Finally, the structures of the system are determined. This paper examines the example of the control service of an iPSS for a water heater tank capping press. An improved AP clustering algorithm is used to determine standardized customer demands, the proposed QFD, and an AD integration model to initially establish a mapping between the customer demands domain and the function domain and clarify the design focus. Next, a QFD- and AD-integrated model is constructed to establish a mapping between the function domain and the structure domain and optimize the control scheme through the quality of its risk prediction. Finally the paper verifies that the upper process and methods can guide the design process effectively in production applications
Weyl-Ambient Geometries
Weyl geometry is a natural extension of conformal geometry with Weyl
covariance mediated by a Weyl connection. We generalize the Fefferman-Graham
(FG) ambient construction for conformal manifolds to a corresponding
construction for Weyl manifolds. We first introduce the Weyl-ambient metric
motivated by the Weyl-Fefferman-Graham (WFG) gauge. From a top-down
perspective, we show that the Weyl-ambient space as a pseudo-Riemannian
geometry induces a codimension-2 Weyl geometry. Then, from a bottom-up
perspective, we start from promoting a conformal manifold into a Weyl manifold
by assigning a Weyl connection to the principal -bundle realizing
a Weyl structure. We show that the Weyl structure admits a well-defined initial
value problem, which determines the Weyl-ambient metric. Through the
Weyl-ambient construction, we also investigate Weyl-covariant tensors on the
Weyl manifold and define extended Weyl-obstruction tensors explicitly.Comment: 42 pages, 1 figure; v3: minor typos fixed; published versio
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