6,370 research outputs found
A technique for automatic real time scoring of several simultaneous sleep electroencephalograms
Automatic real-time scoring of simultaneous sleep electroencephalogram
Sticky Leverage
We develop a tractable general equilibrium model that captures the interplay between nominal long-term corporate debt, inflation, and real aggregates. We show that unanticipated inflation changes the real burden of debt and, more significantly, leads to a debt overhang that distorts future investment and production decisions. For these effects to be both large and very persistent, it is essential that debt maturity exceeds one period. We also show that interest rate rules can help stabilize our economy
Embeddings in Spacetimes Sourced by Scalar Fields
The extension of the Campbell-Magaard embedding theorem to general relativity
with minimally-coupled scalar fields is formulated and proven. The result is
applied to the case of a self-interacting scalar field for which new embeddings
are found, and to Brans-Dicke theory. The relationship between Campbell-Magaard
theorem and the general relativity, Cauchy and initial value problems is
outlined.Comment: RevTEX (11 pages)/ To appear in the Journal of Mathematical Physic
Diels–Alder Reactions During the Biosynthesis of Sorbicillinoids
The sorbicillinoids are a class of biologically active and structurally diverse fungal polyketides arising from sorbicillin. Through co-expression of sorA, sorB, sorC, and sorD from Trichoderma reesei QM6a, the biosynthetic pathway to epoxysorbicillinol and dimeric sorbicillinoids, which resemble Diels–Alder-like and Michael-addition-like products, was reconstituted in Aspergillus oryzae NSAR1. Expression and feeding experiments demonstrated the crucial requirement of the flavin-dependent monooxygenase SorD for the formation of dimeric sorbicillinoids, hybrid sorbicillinoids, and epoxysorbicillinol in vivo. In contrast to prior reports, SorD catalyses neither the oxidation of 2',3'-dihydrosorbicillin to sorbicillin nor the oxidation of sorbicillinol to oxosorbicillinol. This is the first report that both the intermolecular Diels–Alder and Michael dimerization reactions, as well as the epoxidation of sorbicillinol are catalysed in vivo by SorD. © 2020 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA
Cosmological Perturbations in Brane-World Theories: Formalism
We develop a gauge-invariant formalism to describe metric perturbations in
five-dimensional brane-world theories. In particular, this formalism applies to
models originating from heterotic M-theory. We introduce a generalized
longitudinal gauge for scalar perturbations. As an application, we discuss some
aspects of the evolution of fluctuations on the brane. Moreover, we show how
the five-dimensional formalism can be matched to the known four-dimensional one
in the limit where an effective four-dimensional description is appropriate.Comment: 16 pages, no figure, matches version to appear in PR
Interesting consequences of brane cosmology
We discuss cosmology in four dimensions within a context of brane-world
scenario.Such models can predict chaotic inflation with very low reheat
temperature depending on the brane tension. We notice that the gravitino
abundance is different in the brane-world cosmology and by tuning the brane
tension it is possible to get extremely low abundance. We also study
Affleck-Dine baryogenesis in our toy model.Comment: 5 pages, Trivial changes to match the published versio
Dealloying of Platinum-Aluminum Thin Films Part II. Electrode Performance
Highly porous Pt/Al thin film electrodes on yttria stabilized zirconia
electrolytes were prepared by dealloying of co-sputtered Pt/Al films. The
oxygen reduction capability of the resulting electrodes was analyzed in a solid
oxide fuel cell setup at elevated temperatures. During initial heating to 523 K
exceptionally high performances compared to conventional Pt thin film
electrodes were measured. This results from the high internal surface area and
large three phase boundary length obtained by the dealloying process. Exposure
to elevated temperatures of 673 K or 873 K gave rise to degradation of the
electrode performance, which was primarily attributed to the oxidation of
remaining Al in the thin films.Comment: 5 pages, 4 figure
D=7 / D=6 Heterotic Supergravity with Gauged R-Symmetry
We construct a family of chiral anomaly-free supergravity theories in D=6
starting from D=7 supergravity with a gauged noncompact R-symmetry, employing a
Horava-Witten bulk-plus-boundary construction. The gauged noncompact R-symmetry
yields a positive (de Sitter sign) D=6 scalar field potential. Classical
anomaly inflow which is needed to cancel boundary-field loop anomalies requires
careful consideration of the gravitational, gauge, mixed and local
supersymmetry anomalies. Coupling of boundary hypermultiplets requires care
with the Sp(1) gauge connection required to obtain quaternionic Kahler target
manifolds in D=6. This class of gauged R-symmetry models may be of use as
starting points for further compactifications to D=4 that take advantage of the
positive scalar potential, such as those proposed in the scenario of
supersymmetry in large extra dimensions.Comment: 43 pages, plain Latex; Clarification of discussion and references
adde
A Call to Reflect on Evaluation Practices for Failure Detection in Image Classification
Reliable application of machine learning-based decision systems in the wild
is one of the major challenges currently investigated by the field. A large
portion of established approaches aims to detect erroneous predictions by means
of assigning confidence scores. This confidence may be obtained by either
quantifying the model's predictive uncertainty, learning explicit scoring
functions, or assessing whether the input is in line with the training
distribution. Curiously, while these approaches all state to address the same
eventual goal of detecting failures of a classifier upon real-life application,
they currently constitute largely separated research fields with individual
evaluation protocols, which either exclude a substantial part of relevant
methods or ignore large parts of relevant failure sources. In this work, we
systematically reveal current pitfalls caused by these inconsistencies and
derive requirements for a holistic and realistic evaluation of failure
detection. To demonstrate the relevance of this unified perspective, we present
a large-scale empirical study for the first time enabling benchmarking
confidence scoring functions w.r.t all relevant methods and failure sources.
The revelation of a simple softmax response baseline as the overall best
performing method underlines the drastic shortcomings of current evaluation in
the abundance of publicized research on confidence scoring. Code and trained
models are at https://github.com/IML-DKFZ/fd-shifts
Brain Phosphorus Magnetic Resonance Spectroscopy Imaging of Sleep Homeostasis and Restoration in Drug Dependence
Numerous reports have documented a high occurrence of sleep difficulties in drug-dependent populations, prompting researchers to characterize sleep profiles and physiology in drug abusing populations. This mini-review examines studies indicating that drug-dependent populations exhibit alterations in sleep homeostatic and restoration processes in response to sleep deprivation. Sleep deprivation is a principal sleep research tool that results in marked physiological challenge, which provides a means to examine sleep homeostatic processes in response to extended wakefulness. A report from our laboratory demonstrated that following recovery sleep from sleep deprivation, brain high-energy phosphates particularly beta–nucleoside triphosphate (beta-NTP) are markedly increased as measured with phosphorus magnetic resonance spectroscopy (MRS). A more recent study examined the effects of sleep deprivation in opiate-dependent methadone-maintained (MM) subjects. The study demonstrated increases in brain beta-NTP following recovery sleep. Interestingly, these increases were of a markedly greater magnitude in MM subjects compared to control subjects. A similar study examined sleep deprivation in cocaine-dependent subjects demonstrating that cocaine-dependent subjects exhibit greater increases in brain beta-NTP following recovery sleep when compared to control subjects. The studies suggest that sleep deprivation in both MM subjects and cocaine-dependent subjects is characterized by greater changes in brain ATP levels than control subjects. Greater enhancements in brain ATP following recovery sleep may reflect a greater disruption to or impact of sleep deprivation in drug dependent subjects, whereby sleep restoration processes may be unable to properly regulate brain ATP and maintain brain high-energy equilibrium. These studies support the notion of a greater susceptibility to sleep loss in drug dependent populations. Additional sleep studies in drug abusing populations are needed, particularly those that examine potential differential effects of sleep deprivation
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