603 research outputs found
Holographic Shear Viscosity in Hyperscaling Violating Theories without Translational Invariance
In this paper we investigate the ratio of shear viscosity to entropy density,
, in hyperscaling violating geometry with lattice structure. We show
that the scaling relation with hyperscaling violation gives a strong constraint
to the mass of graviton and usually leads to a power law of temperature,
. We find the exponent can be greater than two
such that the new bound for viscosity raised in arXiv:1601.02757 is violated.
Our above observation is testified by constructing specific solutions with UV
completion in various holographic models. Finally, we compare the boundedness
of with the behavior of entanglement entropy and conjecture a relation
between them.Comment: 38 pages, 8 figures: 1 appendix added, 2 figures added, 1 references
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WaveAttack: Asymmetric Frequency Obfuscation-based Backdoor Attacks Against Deep Neural Networks
Due to the popularity of Artificial Intelligence (AI) technology, numerous
backdoor attacks are designed by adversaries to mislead deep neural network
predictions by manipulating training samples and training processes. Although
backdoor attacks are effective in various real scenarios, they still suffer
from the problems of both low fidelity of poisoned samples and non-negligible
transfer in latent space, which make them easily detectable by existing
backdoor detection algorithms. To overcome the weakness, this paper proposes a
novel frequency-based backdoor attack method named WaveAttack, which obtains
image high-frequency features through Discrete Wavelet Transform (DWT) to
generate backdoor triggers. Furthermore, we introduce an asymmetric frequency
obfuscation method, which can add an adaptive residual in the training and
inference stage to improve the impact of triggers and further enhance the
effectiveness of WaveAttack. Comprehensive experimental results show that
WaveAttack not only achieves higher stealthiness and effectiveness, but also
outperforms state-of-the-art (SOTA) backdoor attack methods in the fidelity of
images by up to 28.27\% improvement in PSNR, 1.61\% improvement in SSIM, and
70.59\% reduction in IS
Towards Generalist Robots: A Promising Paradigm via Generative Simulation
This document serves as a position paper that outlines the authors' vision
for a potential pathway towards generalist robots. The purpose of this document
is to share the excitement of the authors with the community and highlight a
promising research direction in robotics and AI. The authors believe the
proposed paradigm is a feasible path towards accomplishing the long-standing
goal of robotics research: deploying robots, or embodied AI agents more
broadly, in various non-factory real-world settings to perform diverse tasks.
This document presents a specific idea for mining knowledge in the latest
large-scale foundation models for robotics research. Instead of directly using
or adapting these models to produce low-level policies and actions, it
advocates for a fully automated generative pipeline (termed as generative
simulation), which uses these models to generate diversified tasks, scenes and
training supervisions at scale, thereby scaling up low-level skill learning and
ultimately leading to a foundation model for robotics that empowers generalist
robots. The authors are actively pursuing this direction, but in the meantime,
they recognize that the ambitious goal of building generalist robots with
large-scale policy training demands significant resources such as computing
power and hardware, and research groups in academia alone may face severe
resource constraints in implementing the entire vision. Therefore, the authors
believe sharing their thoughts at this early stage could foster discussions,
attract interest towards the proposed pathway and related topics from industry
groups, and potentially spur significant technical advancements in the field
A dinuclear copper complex: bisÂ(ÎŒ-4-aminoÂbenzoato)bisÂ[aqua(1,10-phenanthroline)copper(II)] dichloride bis(4-aminoÂbenzoic acid) dihydrate
The title complex, [Cu2(C7H6NO2)2(C12H8N2)2(H2O)2]·2C7H7NO2·2H2O, consists of a dinuclear [Cu2(C7H6NO2)2(C12H8N2)2(H2O)2]2+ cation, two Clâ anions, two 4-aminoÂbenzoic acid molÂecules and two disordered water molÂecules (site occupancy factors 0.5). The Cu(II) ion adopts a distorted square-pyramidal geometry formed by two N atoms from the 1,10-phenanthroline ligand and two O atoms of the two 4-aminoÂbenzoic acid ligands and one water O atom. The CuâŻCu separation is 3.109â
(2)â
Ă
. A twofold axis passes through the mid-point of the CuâŻCu vector
Drug-herb interactions between Scutellaria baicalensis and pharmaceutical drugs : insights from experimental studies, mechanistic actions to clinical applications
Whilst the popular use of herbal medicine globally, it poses challenges in managing potential drug-herb interaction. There are two folds of the drug-herb interaction, a beneficial interaction that may improve therapeutic outcome and minimise the toxicity of drug desirably; by contrast, negative interaction may evoke unwanted clinical consequences, especially with drugs of narrow therapeutic index. Scutellaria baicalensis Georgi is one of the most popular medicinal plants used in Asian countries. It has been widely used for treating various diseases and conditions such as cancer, diabetes, inflammation, and oxidative stress. Studies on its extract and bioactive compounds have shown pharmacodynamic and pharmacokinetic interactions with a wide range of pharmaceutical drugs as evidenced by plenty of in vitro, in vivo and clinical studies. Notably, S. baicalensis and its bioactives including baicalein, baicalin and wogonin exhibited synergistic interactions with many pharmaceutical drugs to enhance their efficacy, reduce toxicity or overcome drug resistance to combat complex diseases such as cancer, diabetes and infectious diseases. On the other hand, S. baicalensis and its bioactives also affected the pharmacokinetic profile of many drugs in absorption, distribution, metabolism and elimination via the regulatory actions of the efflux pumps and cytochrome P450 enzymes. This review provides comprehensive references of the observed pharmacodynamic and pharmacokinetic drug interactions of Scutellaria baicalensis and its bioactives. We have elucidated the interaction with detailed mechanistic actions, identified the knowledge gaps for future research and potential clinical implications. Such knowledge is important for the practice of both conventional and complementary medicines, and it is essential to ensure the safe use of related herbal medicines. The review may be of great interest to practitioners, consumers, clinicians who require comprehensive information on the possible drug interactions with S. baicalensis and its bioactives
Novel Microfiber Sensor and Its Biosensing Application for Detection of hCG Based on a Singlemode-Tapered Hollow Core-Singlemode Fiber Structure
A novel microfiber sensor is proposed and demonstrated based on a singlemode-tapered hollow core -singlemode (STHS) fiber structure. Experimentally a STHS with taper waist diameter of 26.5 Όm has been fabricated and RI sensitivity of 816, 1601.86, and 4775.5 nm/RIU has been achieved with RI ranges from 1.3335 to 1.3395 , from 1.369 to 1.378, and from 1.409 to 1.4175 respectively, which agrees very well with simulated RI sensitivity of 885, 1517, and 4540 nm/RIU at RI ranges from 1.3335 to 1.337, from 1.37 to 1.374, and from 1.41 to 1.414 . The taper waist diameter has impact on both temperature and strain sensitivity of the sensor structure: (1) the smaller the waist diameter, the higher the temperature sensitivity, and experimentally 26.82 pm/°C has been achieved with a taper waist diameter of 21.4 Όm; (2) as waist diameter decrease, strain sensitivity increase and 7.62 pm/ΌΔ has been achieved with a taper diameter of 20.3 Όm. The developed sensor was then functionalized for human chorionic gonadotropin (hCG) detection as an example for biosensing application. Experimentally for hCG concentration of 5 mIU/ml, the sensor has 0.5 nm wavelength shift, equivalent to limit of detection (LOD) of 0.6 mIU/ml by defining 3 times of the wavelength variation (0.06 nm) as measurement limit. The biosensor demonstrated relatively good reproducibility and specificity, which has potential for real medical diagnostics and other applications
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