3,671 research outputs found
Neutrino decay as a possible interpretation to the MiniBooNE observation with unparticle scenario
In a new measurement on neutrino oscillation , the
MiniBooNE Collaboration observes an excess of electron-like events at low
energy and the phenomenon may demand an explanation which obviously is beyond
the oscillation picuture. We propose that heavier neutrino decaying
into a lighter one via the transition process
where denotes any light products, could be a natural mechanism. The
theoretical model we employ here is the unparticle scenario established by
Georgi. We have studied two particular modes \nu_\mu\to \nu_e+\Un and
. Unfortunately, the number coming out from
the computation is too small to explain the observation. Moreover, our results
are consistent with the cosmology constraint on the neutrino lifetime and the
theoretical estimation made by other groups, therefore we can conclude that
even though neutrino decay seems plausible in this case, it indeed cannot be
the source of the peak at lower energy observed by the MiniBooNE collaboration
and there should be other mechanisms responsible for the phenomenon.Comment: 14 pages, conclusions are changed; published version for EPJ
Expedited circular dichroism prediction and engineering in two-dimensional diffractive chiral metamaterials leveraging a powerful model-agnostic data enhancement algorithm
A model-agnostic data enhancement (MADE) algorithm is proposed to comprehensively investigate the circular dichroism (CD) properties in the higher-order diffracted patterns of two-dimensional (2D) chiral metamaterials possessing different parameters. A remarkable feature of MADE algorithm is that it leverages substantially less data from a target problem and some training data from another already solved topic to generate a domain adaptation dataset, which is then used for model training at no expense of abundant computational resources. Specifically, nine differently shaped 2D chiral metamaterials with different unit period and one special sample containing multiple chiral parameters are both studied utilizing the MADE algorithm where three machine learning models (i.e, artificial neural network, random forest regression, support vector regression) are applied. The conventional rigorous coupled wave analysis approach is adopted to capture CD responses of these metamaterials and then assist the training of MADE, while the additional training data are obtained from our previous work. Significant evaluations regarding optical chirality in 2D metamaterials possessing various shape, unit period, width, bridge length, and separation length are performed in a fast, accurate, and data-friendly manner. The MADE framework introduced in this work is extremely important for the large-scale, efficient design of 2D diffractive metamaterials and more advanced photonic devices
Collaborative Vehicular Edge Computing Networks: Architecture Design and Research Challenges
The emergence of augmented reality (AR), autonomous driving and other new applications have greatly enriched the functionality of the vehicular networks. However, these applications usually require complex calculations and large amounts of storage, which puts tremendous pressure on traditional vehicular networks. Mobile edge computing (MEC) is proposed as a prospective technique to extend computing and storage resources to the edge of the network. Combined with MEC, the computing and storage capabilities of the vehicular network can be further enhanced. Therefore, in this paper, we explore the novel collaborative vehicular edge computing network (CVECN) architecture. We first review the work related to MEC and vehicular networks. Then we discuss the design principles of CVECN. Based on the principles, we present the detailed CVECN architecture, and introduce the corresponding functional modules, communication process, as well as the installation and deployment ideas. Furthermore, the promising technical challenges, including collaborative coalition formation, collaborative task offloading and mobility management, are presented. And some potential research issues for future research are highlighted. Finally, simulation results are verified that the proposed CVECN can significantly improve network performance
Local Magnetic Field Role in Star Formation
We highlight distinct and systematic observational features of magnetic field
morphologies in polarized submm dust continuum. We illustrate this with
specific examples and show statistical trends from a sample of 50 star-forming
regions.Comment: 4 pages, 3 figures; to appear in the EAS Proceedings of the 6th
Zermatt ISM Symposium "Conditions and Impact of Star Formation from Lab to
Space", September 201
Fractional quantum Hall effect in the absence of Landau levels
It has been well-known that topological phenomena with fractional
excitations, i.e., the fractional quantum Hall effect (FQHE) \cite{Tsui1982}
will emerge when electrons move in Landau levels. In this letter, we report the
discovery of the FQHE in the absence of Landau levels in an interacting fermion
model. The non-interacting part of our Hamiltonian is the recently proposed
topologically nontrivial flat band model on the checkerboard lattice
\cite{sun}. In the presence of nearest-neighboring repulsion (), we find
that at 1/3 filling, the Fermi-liquid state is unstable towards FQHE. At 1/5
filling, however, a next-nearest-neighboring repulsion is needed for the
occurrence of the 1/5 FQHE when is not too strong. We demonstrate the
characteristic features of these novel states and determine the phase diagram
correspondingly.Comment: 6 pages and 4 figure
Magnetic Fields and Massive Star Formation
Massive stars ( \msun) typically form in parsec-scale molecular clumps
that collapse and fragment, leading to the birth of a cluster of stellar
objects. We investigate the role of magnetic fields in this process through
dust polarization at 870 m obtained with the Submillimeter Array (SMA).
The SMA observations reveal polarization at scales of \lsim 0.1 pc. The
polarization pattern in these objects ranges from ordered hour-glass
configurations to more chaotic distributions. By comparing the SMA data with
the single dish data at parsec scales, we found that magnetic fields at dense
core scales are either aligned within of or perpendicular to the
parsec-scale magnetic fields. This finding indicates that magnetic fields play
an important role during the collapse and fragmentation of massive molecular
clumps and the formation of dense cores. We further compare magnetic fields in
dense cores with the major axis of molecular outflows. Despite a limited number
of outflows, we found that the outflow axis appears to be randomly oriented
with respect to the magnetic field in the core. This result suggests that at
the scale of accretion disks (\lsim 10^3 AU), angular momentum and dynamic
interactions possibly due to close binary or multiple systems dominate over
magnetic fields. With this unprecedentedly large sample massive clumps, we
argue on a statistical basis that magnetic fields play an important role during
the formation of dense cores at spatial scale of 0.01 - 0.1 pc in the context
of massive star and cluster star formation.Comment: Accepted for publication in Astrophysical Journa
Pharmacogenetic aspects of the use of tacrolimus in renal transplantation: Recent developments and ethnic considerations
Introduction: Tacrolimus (Tac) is effective in preventing acute rejection but has considerable toxicity and inter-individual variability in pharmacokinetics and pharmacodynamics. Part of this is explained by polymorphisms in genes encoding Tac-metabolizing enzymes and transporters. A better understanding of Tac pharmacokinetics and pharmacodynamics may help to minimize different outcomes amongst transplant recipients by personalizing immunosuppression.Areas covered: The pharmacogenetic contribution of Tac metabolism will be examined, with a focus on recent discoveries, new developments and ethnic considerations.Expert opinion: The strongest and most consistent association in pharmacogenetics is between the CYP3A5 genotype and Tac dose requirement, with CYP3A5 expressers having a ∼ 40-50% higher dose requirement compared to non-expressers. Two recent randomized-controlled clinical trials using CYP3A5 genotype, however, did not show a decrease in acute rejections nor reduced toxicity. CYP3A4∗22, CYP3A4∗26, and POR∗28 are also associated with Tac dose requirements and may be included to provide the expected improvement of Tac therapy. Studies focusing on the intracellular drug concentrations and on calcineurin inhibitor-induced nephrotoxicity also seem promising. For all studies, however, the ethnic prevalence of genotypes should be taken into account, as this may significantly impact the effect of pre-emptive genotyping
Impact of fish consumption on all-cause mortality in older people with and without dementia: a community-based cohort study
BACKGROUND
Increased fish consumption reduces the risk of dementia. However, it is unknown whether fish consumption reduced all-cause mortality in people with dementia. The purpose of the study is to investigate the association of fish consumption with all-cause mortality in older people with dementia versus those without dementia.
METHODS
Using a standard method of the Geriatric Mental State, we interviewed 4165 participants aged ≥ 60 years who were randomly recruited from five provinces in China during 2007-2009 to collect the baseline data of socio-demography, disease risk factors, histories of disease, and details of dietary intakes, and diagnosed dementia (n = 406). They were followed up for vital status until 2012.
RESULTS
The cohort follow-up documented 329 deaths; 61 were in participants with dementia (55.3 per 1000 person-years) and 224 were those without dementia (22.3). In all participants, the risk of all-cause mortality was reduced with fish intake at " ≥ twice a week" (multivariate-adjusted hazard ratio 0.58, 95% CI 0.34-0.96) and at "once a week or less" (0.79, 0.53-1.18) compared to "never eat" over the past two years. In participants without baseline dementia, the corresponding HRs for all-cause mortality were 0.57 (0.33-0.98) and 0.85 (0.55-1.31), while in participants with dementia were 1.36 (0.28-6.60) and 1.05 (0.30-3.66), respectively.
CONCLUSION
This study reveals that consumption of fish in older age reduced all-cause mortality in older people without dementia, but not in people with dementia. Fish intake should be increased in older people in general, prior to the development of dementia in the hope of preventing dementia and prolonging life
Targeting CBLB as a potential therapeutic approach for disseminated candidiasis
We thank J.M. Penninger (University of Toronto) for providing Cblb−/− mice, Y. Iwakura (Tokyo University of Science) for providing Clec4n−/− mice, S. Lipkowitz (National Cancer Institute, US National Institutes of Health) for providing Cblb constructs, X. Lin (MD Anderson Cancer Center) for providing the antibody to mouse dectin-3 and Card9−/− bone marrow cells, P.R. Sundstrom (Dartmouth University) for providing the C. albicans cap1 mutant, and L.D. Chaves (University at Buffalo) for flow cytometric analysis of myeloid cells in the kidneys. We also thank A. Lovett-Racke (Ohio State University) for her advice on in vivo Cblb-knockdown experiments. This work was supported by the US National Institutes of Health (grants R01 AI090901, R01 AI123253, and R21 AI117547; all to J.Z.), the American Heart Association (AHA Great Rivers Associate Grant-in-Aid grant 16GRNT26990004; J.Z.), a start-up fund from the Ohio State University College of Medicine (J.Z.), and the Wellcome Trust (G.D.B.).Peer reviewedPostprin
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