15,124 research outputs found
Homotopical Minimal Measures for Geodesic flows on Surfaces of Higher Genus
We study the homotopical minimal measures for positive definite autonomous
Lagrangian systems. Homotopical minimal measures are action-minimizers in their
homotopy classes, while the classical minimal measures (Mather measures) are
action-minimizers in homology classes. Homotopical minimal measures are much
more general, they are not necessarily homological action-minimizers. However,
some of them can be obtained from the classical ones by lifting them to
finite-fold covering spaces. We apply this idea of finite covering to the
geodesic flows on surfaces of higher genus. Let be a compact closed
surface with genus , where is a complete Riemannian metric on .
Consider the positive definite autonomous Lagrangian , whose
Lagrangian system is exactly the complete geodesic
flow on . We show that for each homotopical minimal ergodic measure
that is supported on a nontrivial simple closed periodic trajectory, there is a
finite-fold covering space such that each ergodic preimage of on
is a minimal measure in the classic Mather theory for the Lagrangian
system on
Fractional matching preclusion for butterfly derived networks
The matching preclusion number of a graph is the minimum number of edges whose deletion results in a graph that has neither perfect matchings nor almost perfect matchings. As a generalization, Liu and Liu [18] recently introduced the concept of fractional matching preclusion number. The fractional matching preclusion number (FMP number) of G, denoted by fmp(G), is the minimum number of edges whose deletion leaves the resulting graph without a fractional perfect matching. The fractional strong matching preclusion number (FSMP number) of G, denoted by fsmp(G), is the minimum number of vertices and edges whose deletion leaves the resulting graph without a fractional perfect matching. In this paper, we study the fractional matching preclusion number and the fractional strong matching preclusion number for butterfly network, augmented butterfly network and enhanced butterfly network
The effect of beta-blockers on mortality in patients with heart failure and atrial fibrillation: A meta-analysis of observational cohort and randomized controlled studies
Background: Beta-blockers (BB) are the cornerstone of therapy for heart failure (HF); however, theeffects of these drugs on the prognosis of patients with concomitant atrial fibrillation (AF) remaincontroversial. The objective of this meta-analysis was to evaluate the efficacy of BB on mortality in HFcoexisting with AF.Methods: A systematic search of PubMed, Embase and the Cochrane Library databases wasconducted. Observational cohort studies and randomized controlled trials reporting outcomes ofmortality or HF hospitalizations for patients with HF and AF, being assigned to BB treatment.A non-BB group was also included.Results: A total of 8 clinical studies (5 randomized controlled trials and 3 observational cohort studies)involving 34197 patients were included in the analysis. The pooled analysis demonstrated that BBtreatment was associated with a 22% reduction in relative risk of all-cause mortality in patients withHF and AF (RR: 0.78; 95% CI 0.71–0.86; p < 0.00001; I2 = 27%). The pooled analysis of 5 studiesreported the outcome of HF hospitalization (2774 patients) which showed that BB therapy was not associatedwith a reduction of HF hospitalizations (RR: 0.94; 95% CI 0.79–1.11; p = 0.46; I2 = 38%).Conclusions: Meta-analysis suggests the potential mortality benefit of BB in patients with HF and AF.It was concluded herein that it is premature to deny patients with AF and HF to receive BB therapyconsidering current evidence
GIFD: A Generative Gradient Inversion Method with Feature Domain Optimization
Federated Learning (FL) has recently emerged as a promising distributed
machine learning framework to preserve clients' privacy, by allowing multiple
clients to upload the gradients calculated from their local data to a central
server. Recent studies find that the exchanged gradients also take the risk of
privacy leakage, e.g., an attacker can invert the shared gradients and recover
sensitive data against an FL system by leveraging pre-trained generative
adversarial networks (GAN) as prior knowledge. However, performing gradient
inversion attacks in the latent space of the GAN model limits their expression
ability and generalizability. To tackle these challenges, we propose
\textbf{G}radient \textbf{I}nversion over \textbf{F}eature \textbf{D}omains
(GIFD), which disassembles the GAN model and searches the feature domains of
the intermediate layers. Instead of optimizing only over the initial latent
code, we progressively change the optimized layer, from the initial latent
space to intermediate layers closer to the output images. In addition, we
design a regularizer to avoid unreal image generation by adding a small
ball constraint to the searching range. We also extend GIFD to the
out-of-distribution (OOD) setting, which weakens the assumption that the
training sets of GANs and FL tasks obey the same data distribution. Extensive
experiments demonstrate that our method can achieve pixel-level reconstruction
and is superior to the existing methods. Notably, GIFD also shows great
generalizability under different defense strategy settings and batch sizes.Comment: ICCV 202
2-Amino-4-(2-chloroÂphenÂyl)-7,7-diÂmethyl-5-oxo-5,6,7,8-tetraÂhydro-4H-chromene-3-carbonitrile hemihydrate
The asymmetric unit of the title compound, C18H17ClN2O2·0.5H2O, contains two organic molÂecules and one solvent water molÂecule. In each organic molÂecule, the cycloÂhexene ring adopts an envelope conformation with the C atom connecting the two methyl groups on the flap; the 4H-pyran ring is nearly planar [maximum deviation = 0.113 (3) Å in one molÂecule and 0.089 (3) Å in the other molÂecule] and is approximately perpendicular to the chloroÂphenyl ring [dihedral angle = 86.43 (15)° in one molÂecule and 89.73 (15)° in the other molÂecule]. InterÂmolecular N—H⋯N, N—H⋯O, O—H⋯O and O—H⋯Cl hydrogen bonding is present in the crystal
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