35 research outputs found
Nonperturbative studies of supersymmetric matrix quantum mechanics with 4 and 8 supercharges at finite temperature
We investigate thermodynamic properties of one-dimensional U(N)
supersymmetric gauge theories with 4 and 8 supercharges in the planar large-N
limit by Monte Carlo calculations. Unlike the 16 supercharge case, the
threshold bound state with zero energy is widely believed not to exist in these
models. This led A.V. Smilga to conjecture that the internal energy decreases
exponentially at low temperature instead of decreasing with a power law. In the
16 supercharge case, the latter behavior was predicted from the dual black
0-brane geometry and confirmed recently by Monte Carlo calculations. Our
results for the models with 4 and 8 supercharges indeed support the exponential
behavior, revealing a qualitative difference from the 16 supercharge case.Comment: 16 pages, 7 figures, LaTeX2e, minor corrections in section 3, final
version accepted in JHE
Conformal Quivers and Melting Molecules
Quiver quantum mechanics describes the low energy dynamics of a system of
wrapped D-branes. It captures several aspects of single and multicentered BPS
black hole geometries in four-dimensional supergravity such
as the presence of bound states and an exponential growth of microstates. The
Coulomb branch of an Abelian three node quiver is obtained by integrating out
the massive strings connecting the D-particles. It allows for a scaling regime
corresponding to a deep AdS throat on the gravity side. In this scaling
regime, the Coulomb branch is shown to be an invariant
multi-particle superconformal quantum mechanics. Finally, we integrate out the
strings at finite temperature---rather than in their ground state---and show
how the Coulomb branch `melts' into the Higgs branch at high enough
temperatures. For scaling solutions the melting occurs for arbitrarily small
temperatures, whereas bound states can be metastable and thus long lived.
Throughout the paper, we discuss how far the analogy between the quiver model
and the gravity picture, particularly within the AdS throat, can be taken.Comment: 49 pages, 16 figure
Mutation of Rubie, a Novel Long Non-Coding RNA Located Upstream of Bmp4, Causes Vestibular Malformation in Mice
Background: The vestibular apparatus of the vertebrate inner ear uses three fluid-filled semicircular canals to sense angular acceleration of the head. Malformation of these canals disrupts the sense of balance and frequently causes circling behavior in mice. The Epistatic circler (Ecl) is a complex mutant derived from wildtype SWR/J and C57L/J mice. Ecl circling has been shown to result from the epistatic interaction of an SWR-derived locus on chromosome 14 and a C57L-derived locus on chromosome 4, but the causative genes have not been previously identified. Methodology/Principal Findings: We developed a mouse chromosome substitution strain (CSS-14) that carries an SWR/J chromosome 14 on a C57BL/10J genetic background and, like Ecl, exhibits circling behavior due to lateral semicircular canal malformation. We utilized CSS-14 to identify the chromosome 14 Ecl gene by positional cloning. Our candidate interval is located upstream of bone morphogenetic protein 4 (Bmp4) and contains an inner ear-specific, long non-coding RNA that we have designated Rubie (RNA upstream of Bmp4 expressed in inner ear). Rubie is spliced and polyadenylated, and is expressed in developing semicircular canals. However, we discovered that the SWR/J allele of Rubie is disrupted by an intronic endogenous retrovirus that causes aberrant splicing and premature polyadenylation of the transcript. Rubie lies in the conserved gene desert upstream of Bmp4, within a region previously shown to be important for inner ear expression of Bmp4. We found that the expression patterns of Bmp4 and Rubie are nearly identical in developing inner ears
Extracting black hole physics from the lattice
We perform lattice simulations of N D0-branes at finite temperature in the
decoupling limit, namely 16 supercharge SU(N) Yang-Mills quantum mechanics in
the 't Hooft limit. At low temperature this theory is conjectured to be dual to
certain supergravity black holes. We emphasize that the existence of a
non-compact moduli space renders the partition function of the quantum
mechanics theory divergent, and we perform one loop calculations that
demonstrate this explicitly. In consequence we use a scalar mass term to
regulate this divergence and argue that the dual black hole thermodynamics may
be recovered in the appropriate large N limit as the regulator is removed. We
report on simulations for N up to 5 including the Pfaffian phase, and N up to
12 in the phase quenched approximation. Interestingly, in the former case,
where we may calculate this potentially difficult phase, we find that it
appears to play little role dynamically over the temperature range tested,
which is certainly encouraging for future simulations of this theory.Comment: 36 pages, 7 figure
The Human Phenotype Ontology in 2024: phenotypes around the world
\ua9 The Author(s) 2023. Published by Oxford University Press on behalf of Nucleic Acids Research. The Human Phenotype Ontology (HPO) is a widely used resource that comprehensively organizes and defines the phenotypic features of human disease, enabling computational inference and supporting genomic and phenotypic analyses through semantic similarity and machine learning algorithms. The HPO has widespread applications in clinical diagnostics and translational research, including genomic diagnostics, gene-disease discovery, and cohort analytics. In recent years, groups around the world have developed translations of the HPO from English to other languages, and the HPO browser has been internationalized, allowing users to view HPO term labels and in many cases synonyms and definitions in ten languages in addition to English. Since our last report, a total of 2239 new HPO terms and 49235 new HPO annotations were developed, many in collaboration with external groups in the fields of psychiatry, arthrogryposis, immunology and cardiology. The Medical Action Ontology (MAxO) is a new effort to model treatments and other measures taken for clinical management. Finally, the HPO consortium is contributing to efforts to integrate the HPO and the GA4GH Phenopacket Schema into electronic health records (EHRs) with the goal of more standardized and computable integration of rare disease data in EHRs
CD40L association with protection from severe malaria
CD40 ligand (CD40L), a glycoprotein involved in B cell proliferation, antigen presenting cell activation, and Ig class switching, is important in the immune response to infection. Rare coding mutations in CD40L can lead to life-threatening immunodeficiency but the potential for common variants to alter disease susceptibility remains to be explored. To identify polymorphisms in CD40L, we sequenced 2.3 kb of the 5' flanking region and the first exon of the gene in DNA samples from 36 Gambian females and one chimpanzee. Diversity was lower than the average reported for other areas of the X chromosome, and only two polymorphisms were identified. The polymorphisms were genotyped in DNA samples from 957 Gambian individuals, cases and controls from a study of severe malaria. A significant reduction in risk for severe malaria (OR = 0.52, P = 0.002) was associated with males hemizygous for the CD40L-726C. Analysis by transmission disequilibrium test of 371 cases, for whom DNA from both parents was also available, confirmed the result was not due to stratification (P = 0.04). A similar but non-significant trend was found in females. This preliminary association of a common variant in CD40L with a malaria resistance phenotype encourages further genetic characterization of the role of CD40L in infectious disease