3,445 research outputs found
Horndeski Gravity and the Violation of Reverse Isoperimetric Inequality
We consider Einstein-Horndeski-Maxwell gravity, together with a cosmological
constant and multiple Horndeski axions. We construct charged AdS planar black
holes in general dimensions where the Horndeski anxions span over the planar
directions. We analyse the thermodynamics and obtain the black hole volumes. We
show that the reverse isoperimetric inequality can be violated, implying that
these black holes can store information more efficiently than the Schwarzschild
black hole.Comment: Latex, 25 pages, 1 figure, references adde
Analysis of the Dynamical Behavior of Firms in a Three Layered Modular Assembly Model
This paper formulate an option model considers supplier's reaction as the profit sharing in module production, and analyses it by the agent theory. A dynamic environment in the model of the system of the production of modules of three layers is assumed, and the maker and the supplier are modeled by the technique of Genetic Programming (GP) as an agent who takes the action of selfoptimization. As result, the condition that the agent can exist continuously in the market is requested. In conclusion, violent competition and the selection of the similar agent are found even in the model of the option to consider the profit sharing and the reaction
Ultrafast magnetization enhancement and spin current injection in magnetic multilayers by exciting the nonmagnetic metal
A systematic investigation of spin injection behavior in Au/FM (FM = Fe and
Ni) multilayers is performed using the superdiffusive spin transport theory. By
exciting the nonmagnetic layer, the laser-induced hot electrons may transfer
spin angular momentum into the adjacent ferromagnetic (FM) metals resulting in
ultrafast demagnetization or enhancement. We find that these experimental
phenomena sensitively depend on the particular interface reflectivity of hot
electrons and may reconcile the different observations in experiment.
Stimulated by the ultrafast spin currents carried by the hot electrons, we
propose the multilayer structures to generate highly spin polarized currents
for development of future ultrafast spintronics devices. The spin polarization
of the electric currents carried by the hot electrons can be significantly
enhanced by the joint effects of bulk and interfacial spin filtering. Meanwhile
the intensity of the generated spin current can be optimized by varying the
number of repeated stacking units and the thickness of each metallic layer.Comment: 11 pages, 6 figure
A neglected event in endovascular repair of aortic dissection: acute blood pressure variability during aortic angiography
[Purpose]To investigate acute blood pressure change during aortic angiography in aortic dissection endovascular repair, and analyse the potential risk of this incident.[Method]24 patients with aortic dissection underwent endovascular repair in department of vascular surgery of Changhai hospital between May 2016 and July 2016 were enrolled in this research. Patients were divided into two groups: patients underwent general anesthesia and patients underwent lumbar anesthesia. Blood pressure was monitored by intro-artery catheter. Blood pressure readings were recorded every 10 seconds during the procedure of angiography. Outcome of these patients were observed in hospital. [Result] All patients received endovascular aortic repair, with 19 underwent lumbar anesthesia and 5 underwent general anesthesia. Patients underwent lumbar anesthesia presented temporary blood pressure decrease with average of -11.2±13.4mmHg, while patients underwent general anesthesia presented temporary blood pressure elevation with average of 4.2±6.3mmHg. The Maximum time interval were 26.7±12.7s vs25.8±15.8s, and difference in blood pressure between pre- and post-angiography were 1.53±4.4mmHg vs. 4.6±3.4mmHg, both without significance (P>0.05).[Conclusion] Angiography is an effective factor influencing blood pressure during TEVAR, it’s a potential “trigger” of intra-operative cardiovascular events. Blood pressure should be kept on proper level to avoid cardiovascular events induced by blood pressure variability with angiography. Angiography with General anesthesia has less influence on blood pressure than with lumbar anesthesia
Self-Supervision Can Be a Good Few-Shot Learner
Existing few-shot learning (FSL) methods rely on training with a large
labeled dataset, which prevents them from leveraging abundant unlabeled data.
From an information-theoretic perspective, we propose an effective unsupervised
FSL method, learning representations with self-supervision. Following the
InfoMax principle, our method learns comprehensive representations by capturing
the intrinsic structure of the data. Specifically, we maximize the mutual
information (MI) of instances and their representations with a low-bias MI
estimator to perform self-supervised pre-training. Rather than supervised
pre-training focusing on the discriminable features of the seen classes, our
self-supervised model has less bias toward the seen classes, resulting in
better generalization for unseen classes. We explain that supervised
pre-training and self-supervised pre-training are actually maximizing different
MI objectives. Extensive experiments are further conducted to analyze their FSL
performance with various training settings. Surprisingly, the results show that
self-supervised pre-training can outperform supervised pre-training under the
appropriate conditions. Compared with state-of-the-art FSL methods, our
approach achieves comparable performance on widely used FSL benchmarks without
any labels of the base classes.Comment: ECCV 2022, code: https://github.com/bbbdylan/unisia
Brake or Step On the Gas? Empirical Analyses of Credit Effects on Individual Consumption
Understanding the effects of credit on consumption is crucial for guiding users’ consumption behavior, designing financial marketing strategies, and identifying credit\u27s value in stimulating the economy. Whereas several studies have endeavored on this issue, most simply utilize observations of a single credit channel and/or focus on an overall effect without considering the potentially heterogeneous short-term and long-term consumption changes. This study, leveraging a quasi-experimental design with high-resolution transaction data, examines how people respond to credit in both short- and long-term periods. Results show that credit users’ consumption amount significantly expand by 51.74% after getting access to credit in the short term. However, they ultimately cut their consumption by 4.02% to cope with financial constraints in the long term. We also reveal and quantify the spillover effects of credit on consumption with savings channels. We draw on regulatory focus theory to rationalize the changes on consumers’ consumption behavior after credit activation
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