564 research outputs found
The geometric correlations of leptonic mixing parameters
Leptonic mixing patterns are usually extracted on the basis of groups or
algebraic structures. In this paper, we introduce an alternative geometric
method to study the correlations between the leptonic mixing parameters. At the
3{\sigma} level of the recent global fit data of neutrino oscillations, the
distribution of the scatter points of the angles between the vectors of the
magnitude of the leptonic mixing matrix is analysed. We find that the scatter
points are concentrated on several special regions. Using the data in these
regions, correlations of the leptonic mixing angles and the Dirac CP violating
phase are obtained. The implications of the correlations are shown through the
predicted flavor ratio of high-energy astrophysical neutrinos (HANs) at Earth.Comment: 15 pages, 7 figure
Improve Noise Tolerance of Robust Loss via Noise-Awareness
Robust loss minimization is an important strategy for handling robust
learning issue on noisy labels. Current approaches for designing robust losses
involve the introduction of noise-robust factors, i.e., hyperparameters, to
control the trade-off between noise robustness and learnability. However,
finding suitable hyperparameters for different datasets with noisy labels is a
challenging and time-consuming task. Moreover, existing robust loss methods
usually assume that all training samples share common hyperparameters, which
are independent of instances. This limits the ability of these methods to
distinguish the individual noise properties of different samples and overlooks
the varying contributions of diverse training samples in helping models
understand underlying patterns. To address above issues, we propose to assemble
robust loss with instance-dependent hyperparameters to improve their noise
tolerance with theoretical guarantee. To achieve setting such
instance-dependent hyperparameters for robust loss, we propose a meta-learning
method which is capable of adaptively learning a hyperparameter prediction
function, called Noise-Aware-Robust-Loss-Adjuster (NARL-Adjuster for brevity).
Through mutual amelioration between hyperparameter prediction function and
classifier parameters in our method, both of them can be simultaneously finely
ameliorated and coordinated to attain solutions with good generalization
capability. Four SOTA robust loss functions are attempted to be integrated with
our algorithm, and comprehensive experiments substantiate the general
availability and effectiveness of the proposed method in both its noise
tolerance and performance.Comment: arXiv admin note: text overlap with arXiv:2002.0648
Salvia miltiorrhiza aqueous root extract plays an important role in improving locomotor activity in rats with spinal cord injury
Purpose: To investigate the activity of the aqueous root extract of Salvia miltiorrhiza (S. miltiorrhiza) (Lamiaceae), collected from Anhui Province, China, for the treatment of spinal cord injury (SCI) in Sprague-Dawley (SD) rats.Methods: In total, 30 adult rats were selected and divided into three groups; normal control, untreated and treated. Aqueous root extract of S. miltiorrhiza was introduced intraperitoneally to the treated group. Basso, Beattie and Bresnahan rating scale (BBB) was used to evaluate improvement in locomotor activity after SCI. Total RNA was extracted from tissue sections using Sepasol (NacalaiTesque) and RNA samples were reverse-transcribed using M-MLV reverse transcriptase. BioSense SC-810 Gel Documentation System and Gel-Pro 3.1 software were employed for the analysis of band intensity.Results: A significant reduction in SCI cavity area was observed in the S. miltiorrhiza extract-treated group, relative to the untreated group, after 11 days (0.10 ± 0.05 mm2 treated vs. 0.30 ± 0.01 mm2 untreated). Treatment with root extract also improved the BBB scores; the treated group scored 15, compared to a score of 8 for the untreated group. In addition, the degradation of neurons at the site of injury in the spinal cord was reduced in the treated group compared to the untreated group. Treatment with S. miltiorrhiza aqueous root extract also significantly increased the expression of platelet-derived growth factor-B (PDGF-B) mRNA (p < 0.01).Conclusion: These data suggest that, in addition to other pharmacological activities, S. miltiorrhiza extract has therapeutic potential for the treatment of neuronal degeneration following SCI.Keywords: Salvia Miltiorrhiza, Neurons, Spinal cord injury, Locomotor capacity, Platelet-derived growth factor-B, Basso, Beattie and Bresnahan rating scal
Blood Pressure Reduction Combining Baroreflex Restoration for Stroke Prevention in Hypertension in Rats
Blood pressure reduction is an important and effective strategy in stroke prevention in hypertensives. Recently, we found that baroreflex restoration was also crucial in stroke prevention. The present work was designed to test the hypothesis that a combination of blood pressure reduction and baroreflex restoration may be a new strategy for stroke prevention. In Experiment 1, the effects of ketanserin (0.3, 1, 3, 10 mg/kg), amlodipine (0.3, 1, 2, 3 mg/kg) and their combination (1 + 0.3, 1 + 1, 1 + 2, 1 + 3 mg/kg) on blood pressure and baroreflex sensitivity (BRS) of stroke-prone spontaneously hypertensive rats (SHR-SP) were determined under conscious state. It was found that both amlodipine and ketanserin decreased blood pressure dose-dependently. Ketanserin enfanced BRS from a very small dose but amlodipine enfanced BRS only at largest dose used. At the dose of 1 + 2 mg/kg (ketanserin + amlodipine), the combination possessed the largest synergism on blood pressure reduction. In Experiments 2 and 3, SHR-SP and two-kidney, two-clip (2K2C) renovascular hypertensive rats received life-long treatments with ketanserin (1 mg/kg) and amlodipine (2 mg/kg) or their combination (0.5 + 1, 1 + 2, 2 + 4 mg/kg). The survival time was recorded and the brain lesion was examined. It was found that all kinds of treatments prolonged the survival time of SHR-SP and 2K2C rats. The combination possessed a significantly better effect on stroke prevention than mono-therapies. In conclusion, combination of blood pressure reduction and baroreflex restoration may be a new strategy for the prevention of stroke in hypertension
On Safeguarding Privacy and Security in the Framework of Federated Learning
Motivated by the advancing computational capacity of wireless end-user
equipment (UE), as well as the increasing concerns about sharing private data,
a new machine learning (ML) paradigm has emerged, namely federated learning
(FL). Specifically, FL allows a decoupling of data provision at UEs and ML
model aggregation at a central unit. By training model locally, FL is capable
of avoiding data leakage from the UEs, thereby preserving privacy and security
to some extend. However, even if raw data are not disclosed from UEs,
individual's private information can still be extracted by some recently
discovered attacks in the FL architecture. In this work, we analyze the privacy
and security issues in FL, and raise several challenges on preserving privacy
and security when designing FL systems. In addition, we provide extensive
simulation results to illustrate the discussed issues and possible solutions.Comment: This paper has been accepted by IEEE Network Magazin
NĂ©el Spin Currents in Antiferromagnets
Ferromagnets are known to support spin-polarized currents that control various spin-dependent transport phenomena useful for spintronics. On the contrary, fully compensated antiferromagnets are expected to support only globally spin-neutral currents. Here, we demonstrate that these globally spin-neutral currents can represent the NĂ©el spin currents, i.e., staggered spin currents flowing through different magnetic sublattices. The NĂ©el spin currents emerge in antiferromagnets with strong intrasublattice coupling (hopping) and drive the spin-dependent transport phenomena such as tunneling magnetoresistance (TMR) and spin-transfer torque (STT) in antiferromagnetic tunnel junctions (AFMTJs). Using RuO2 and Fe4GeTe2 as representative antiferromagnets, we predict that the NĂ©el spin currents with a strong staggered spin polarization produce a sizable fieldlike STT capable of the deterministic switching of the NĂ©el vector in the associated AFMTJs. Our work uncovers the previously unexplored potential of fully compensated antiferromagnets and paves a new route to realize the efficient writing and reading of information for antiferromagnetic spintronics
Zinc-blende and wurtzite GaAs quantum dots in nanowires studied using hydrostatic pressure
We report both zinc-blende (ZB) and wurtzite (WZ) crystal phase
self-assembled GaAs quantum dots (QDs) embedding in a single GaAs/AlGaAs
core-shell nanowires (NWs). Optical transitions and single-photon
characteristics of both kinds of QDs have been investigated by measuring
photoluminescence (PL) and time-resolved PL spectra upon application of
hydrostatic pressure. We find that the ZB QDs are of direct band gap transition
with short recombination lifetime (~1 ns) and higher pressure coefficient
(75-100 meV/GPa). On the contrary, the WZ QDs undergo a direct-to-pseudodirect
bandgap transition as a result of quantum confinement effect, with remarkably
longer exciton lifetime (4.5-74.5 ns) and smaller pressure coefficient (28-53
meV/GPa). These fundamentally physical properties are further examined by
performing state-of-the-art atomistic pseudopotential calculations
- …