481 research outputs found
Prompt neutrinos and intrinsic charm at SHiP
We present a new evaluation of the far-forward neutrino plus antineutrino
flux and number of events from charm hadron decays in a 400 GeV proton beam
dump experiment like the Search for Hidden Particles (SHiP). Using
next-to-leading order perturbative QCD and a model for intrinsic charm, we
include intrinsic transverse momentum effects and other kinematic angular
corrections. We compare this flux to a far-forward flux evaluated with
next-to-leading order perturbative QCD, without intrinsic transverse momentum,
that used the angular distribution of charm quarks rather than the neutrinos
from their decays. The tau neutrino plus antineutrino number of events in the
perturbative QCD evaluation is reduced by a factor of about three when
intrinsic transverse momentum and the full decay kinematics are included. We
show that intrinsic charm contributions can significantly enhance the number of
events from neutrinos from charm hadron decays. Measurements of the number of
events from tau neutrino plus antineutrino interactions and of the muon charge
asymmetry as a function of energy can be used to constrain intrinsic charm
models.Comment: 39 pages, 18 figures; v2 with revisions of text for clarity, version
to be published in JHE
Systematics, biology, ecology And zoogeography of holothurians: Studies on regeneration in the holothurian Holothuria (metriatyla) scabra Jaeger
The histological studies made on regeneration oiHolothuria (Metriatyla) scabra revealed that the alimentary
canal regenerates as a thickening from the original mesentery through mitotic proliferation. The presence of groups
of morula cells at the anterior and posterior remnants, during regeneration suggests their possible role in the
process of wound healing. The circular muscle is formed by the de-differentiation and reorganization of the circular
muscle fibres that are already present. The haemal rudiment is formed within three days as a projection of the
mesenterial thickening. The respiratory tree originates as a solid rudimentary protrubarance from the ruptured
end of the respiratory tree. The rate of regeneration, in all the tissues studied, seems to be more rapid when
compared to that of temperate forms
DeepCut: Object Segmentation from Bounding Box Annotations using Convolutional Neural Networks
In this paper, we propose DeepCut, a method to obtain pixelwise object
segmentations given an image dataset labelled with bounding box annotations. It
extends the approach of the well-known GrabCut method to include machine
learning by training a neural network classifier from bounding box annotations.
We formulate the problem as an energy minimisation problem over a
densely-connected conditional random field and iteratively update the training
targets to obtain pixelwise object segmentations. Additionally, we propose
variants of the DeepCut method and compare those to a naive approach to CNN
training under weak supervision. We test its applicability to solve brain and
lung segmentation problems on a challenging fetal magnetic resonance dataset
and obtain encouraging results in terms of accuracy
A small molecule ApoE4-targeted therapeutic candidate that normalizes sirtuin 1 levels and improves cognition in an Alzheimer's disease mouse model.
We describe here the results from the testing of a small molecule first-in-class apolipoprotein E4 (ApoE4)-targeted sirtuin1 (SirT1) enhancer, A03, that increases the levels of the neuroprotective enzyme SirT1 while not affecting levels of neurotoxic sirtuin 2 (SirT2) in vitro in ApoE4-transfected cells. A03 was identified by high-throughput screening (HTS) and found to be orally bioavailable and brain penetrant. In vivo, A03 treatment increased SirT1 levels in the hippocampus of 5XFAD-ApoE4 (E4FAD) Alzheimer's disease (AD) model mice and elicited cognitive improvement while inducing no observed toxicity. We were able to resolve the enantiomers of A03 and show using in vitro models that the L-enantiomer was more potent than the corresponding D-enantiomer in increasing SirT1 levels. ApoE4 expression has been shown to decrease the level of the NAD-dependent deacetylase and major longevity determinant SirT1 in brain tissue and serum of AD patients as compared to normal controls. A deficiency in SirT1 level has been recently implicated in increased tau acetylation, a dominant post-translational modification and key pathological event in AD and tauopathies. Therefore, as a novel approach to therapeutic development for AD, we targeted identification of compounds that enhance and normalize brain SirT1 levels
Studies on amylase activity of an amylolytic bacterium isolated from estuarine soil
Diverse microscopic, macroscopic and biochemical analysis of a starch degrading amylolytic bacterial strain isolated from the soil sample of Rajakkamangalam estuary, Kanyakumari district, Tamil Nadu, India, revealed its identity to the genus Bacillus. Maximum growth was observed at 12 h when the bacteria was cultured in minimal agar media with 2% starch maintained for 12 h, at 37°C and pH 5.5, 7.5 and 8.5. Highest enzyme action as revealed by glucose production in the media was observed at pH 8.0, temperature 30°C and in the presence of 10 mM calcium (Ca). Enzyme activity gradually got reduced with the addition of increasing concentrations of ethylenediaminetetraacetic acid (EDTA), confirming the need for calcium for enzyme action. The amylase produced in the medium was isolated by centrifugation and partially purified by ammonium sulphate fractionation followed by dialysis.Key words: Amylase, bacteria, amylase activity, pH sensitivity, estuarine soil
Forward production of prompt neutrinos from charm in the atmosphere and at high energy colliders
The high-energy atmospheric neutrino flux is dominated by neutrinos from the
decays of charmed hadrons produced in the forward direction by cosmic ray
interactions with air nuclei. We evaluate the charm contributions to the prompt
atmospheric neutrino flux as a function of the center-of-mass energy
of the hadronic collision and of the center-of-mass rapidity of the
produced charm hadron. Uncertainties associated with parton distribution
functions are also evaluated as a function of . We find that the
coverage of LHCb for forward heavy-flavour production, complemented by the
angular coverage of present and future forward neutrino experiments at the LHC,
bracket the most interesting regions for the prompt atmospheric neutrino
flux. At TeV foreseen for the HL-LHC phase, nucleon collisions in
air contribute to the prompt neutrino flux prominently below ~GeV. Measurements of forward charm and/or forward neutrinos produced in
hadron collisions up to TeV, which might become possible at the
FCC, are relevant for the prompt atmospheric neutrino flux up to
GeV and beyond.Comment: 29 pages, 11 figure
Cross-Cultural Pedagogy: Practical Strategies for a Successful Interprofessional Study Abroad Course
This article discusses some practical strategies for designing and implementing a cross-cultural interprofessional study abroad course, including pre-departure preparation, facilitating small groups with local students, establishing a weekly theme, utilizing role-play and reflective assignments, and implementing meaningful evaluation strategies. These strategies were based on three years of experience and were found to effectively increase students’ cultural competence and self-confidence, as evidenced by student evaluations and results from a focus group conducted one year after the course. Short term study abroad courses with appropriate pedagogical design are significant strategies for health profession programs in the face of growing diversity and globalization
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