126,576 research outputs found
A category of quantum categories
Quantum categories were introduced in [4] as generalizations of both
bi(co)algebroids and small categories. We clarify details of that work. In
particular, we show explicitly how the monadic definition of a quantum category
unpacks to a set of axioms close to the definitions of a bialgebroid in the
Hopf algebraic literature. We define notions of functor and natural
transformation for quantum categories.Comment: Revised and expanded. A lot of diagrams. 40 page
Precise limits from lepton flavour violating processes on the Littlest Higgs model with T-parity
We recalculate the leading one-loop contributions to mu > e gamma and mu ->
eee in the Littlest Higgs model with T-parity, recovering previous results for
the former. When all the Goldstone interactions are taken into account, the
latter is also ultraviolet finite. The present experimental limits on these
processes require a somewhat heavy effective scale ~2.5 TeV, or the flavour
alignment of the Yukawa couplings of light and heavy leptons at the ~10% level,
or the splitting of heavy lepton masses to a similar precision. Present limits
on tau decays set no bounds on the corresponding parameters involving the tau
leptonComment: 41 pages, 11 figures; v3: matches published version in JHE
Phenolic content of Hypodaphnis Zenkeri and its antioxidant effects against fenton reactions’ mediated oxidative injuries on liver homogenate
Under oxidative stress conditions, endogenous antioxidant defenses are unable to completely inactivate the free radicals generated by an excessive production of reactive oxygen species (ROS). This state causes serious cell damage leading to a variety of human diseases. Natural antioxidants can protect cells against oxidative stress. Hypaodaphnis zenkeri (H. zenkiri) is a plant consumed as a spice in the Cameroonian diet, and its bark has been used in traditional medicine for the treatment of several diseases. The present study aims at investigating the antioxidant activity, which includes free radical scavenging and protective properties of an extract from H. Zenkiri against oxidative damage on a liver homogenate. The free radical assays determined the scavenging activities of 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl (OH), nitrite oxide (NO) and 2,2-azinobis(3-ethylbenzthiazoline)-6-sulfonic acid (ABTS) radicals and the enzymes, whose protection was to be considered in the liver homogenate, including superoxide dismutase, catalase, and peroxidase. The antioxidative activities were studied using the ferric reducing antioxidant power (FRAP), reductive activity, and phosphomolybdenum antioxidant power (PAP) methods. In addition, the phenolic contents of the extracts were examined. The results showed that these extracts demonstrated significant scavenging properties and antioxidant activities, with the hydro-ethanolic extract of the bark of H. zenkeri (EEH) being the most potent. This extract had the highest total polyphenol (21.77 ± 0.05 mg caffeic acid (CAE)/g dried extract (DE)) and flavonoids (3.34 ± 0.13 mg quercetin (QE)/g dried extract) content. The same extract had significantly greater protective effects on enzyme activities compared to other extracts. The high performance liquied chromatography (HPLC) profile showed higher levels of caffeic acid, OH-tyrosol acid, and rutin in the leaves compared to the bark of H. zenkeri. In conclusion, the ethanolic and hydro-ethanolic extracts of the bark and leaves from H. zenkeri showed an antioxidant and protective potential against oxidative damage
The Extreme Energy Events HECR array: status and perspectives
The Extreme Energy Events Project is a synchronous sparse array of 52
tracking detectors for studying High Energy Cosmic Rays (HECR) and Cosmic
Rays-related phenomena. The observatory is also meant to address Long Distance
Correlation (LDC) phenomena: the network is deployed over a broad area covering
10 degrees in latitude and 11 in longitude. An overview of a set of preliminary
results is given, extending from the study of local muon flux dependance on
solar activity to the investigation of the upward-going component of muon flux
traversing the EEE stations; from the search for anisotropies at the sub-TeV
scale to the hints for observations of km-scale Extensive Air Shower (EAS).Comment: XXV ECRS 2016 Proceedings - eConf C16-09-04.
Charged Lepton Flavor Violation in a class of Radiative Neutrino Mass Generation Models
We investigate charged lepton flavor violating processes , and conversion in nuclei for
a class of three-loop radiative neutrino mass generation models with
electroweak multiplets of increasing order. We find that, because of certain
cancellations among various one-loop diagrams which give the dipole and
non-dipole contributions in effective vertex and Z-penguin
contribution in effective vertex, the flavor violating processes
and conversion in nuclei become highly
suppressed compared to process. Therefore,
the observation of such pattern in LFV processes may reveal the radiative
mechanism behind neutrino mass generation.Comment: 13 pages, 6 figure
Asymptotic near nucleus structure of the electron-interaction potential in local effective potential theories
In local effective potential theories of electronic structure, the electron
correlations due to the Pauli exclusion principle, Coulomb repulsion, and
correlation-kinetic effects, are all incorporated in the local
electron-interaction potential . In previous work, it has been
shown that for spherically symmetric or sphericalized systems, the asymptotic
near nucleus expansion of this potential is , with being finite. By assuming that the Schr\"odinger and
local effective potential theory wave functions are analytic near the nucleus
of atoms, we prove the following via Quantal density functional theory (Q-DFT):
(i) correlations due to the Pauli principle and Coulomb correlations do not
contribute to the linear structure; (ii) these Pauli and Coulomb correlations
contribute quadratically; (iii) the linear structure is {\em solely} due to
correlation-kinetic effects, the contributions of these effects being
determined analytically. We also derive by application of adiabatic coupling
constant perturbation theory via Q-DFT (iv) the asymptotic near nucleus
expansion of the Hohenberg-Kohn-Sham theory exchange and
correlation potentials. These functions also approach the
nucleus linearly with the linear term of being {\em solely} due
to the lowest-order correlation kinetic effects, and the linear term of
being due {\em solely} to the higher-order correlation kinetic
contributions. The above conclusions are equally valid for systems of arbitrary
symmetry, provided spherical averages of the properties are employed.Comment: 9 pages. Accepted for publication in Phys. Rev.
Is evidence of evidence evidence? Screening-off vs. no-defeaters
I argue elsewhere (Roche 2014) that evidence of evidence is evidence under screening-off. Tal and Comesaña (2017) argue that my appeal to screening-off is subject to two objections. They then propose an evidence of evidence thesis involving the notion of a defeater. There is much to learn from their very careful discussion. I argue, though, that their objections fail and that their evidence of evidence thesis is open to counterexample
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