294 research outputs found
Energy loss distributions of 7 TeV protons channeled in a bent silicon crystals
The energy loss distributions of relativistic protons axially channeled through the bent <100> Si crystals, with the constant curvature radius, R = 50 m, are studied here. The proton energy is 7 TeV and the thickness of the crystal is varied from 1 mm to 5 mm, which corresponds to the reduced crystal thickness, L, from 2.1 to 10.6, respectively. The proton energy was chosen in accordance with the large hadron collider project, at the European Organization for Nuclear Research, in Geneva, Switzerland. The energy loss distributions of the channeled protons were generated by the computer simulation method using the numerical solution of the proton equations of motion in the transverse plane. Dispersion of the proton scattering angle caused by its collisions with the crystal’s electrons was taken into account. [Projekat Ministarstva nauke Republike Srbije, br. III 45006
Covariant three-body equations in phi^3 field theory
We derive four-dimensional relativistic three-body equations for the case of
a field theory with a three-point interaction vertex. These equations describe
the coupled 2->2, 2->3, and 3->3 processes, and provide the means of
calculating the kernel of the 2->2 Bethe-Salpeter equation. Our equations
differ from all previous formulations in two essential ways. Firstly, we have
overcome the overcounting problems inherent in earlier works. Secondly, we have
retained all possible two-body forces when one particle is a spectator. In this
respect, we show how it is necessary to also retain certain three-body forces
as these can give rise to (previously overlooked) two-body forces when used in
a 2->3 process. The revealing of such hidden two-body forces gives rise to a
further novel feature of our equations, namely, to the appearance of a number
of subtraction terms. In the case of the piNN system, for example, the NN
potential involves a subtraction term where two pions, exchanged between the
nucleons, interact with each other through the pi-pi t-matrix. The necessity of
an input pi-pi interaction is surprising and contrasts markedly with the
corresponding three-dimensional description of the piNN system where no such
interaction explicitly appears. This illustrates the somewhat unexpected result
that the four-dimensional equations differ from the three-dimensional ones even
at the operator level.Comment: 33, FIAS-R-22
Clinical and functional characterisation of a novel TNFRSF1A c.605T > A/V173D cleavage site mutation associated with tumour necrosis factor receptor-associated periodic fever syndrome (TRAPS), cardiovascular complications and excellent response to etanercept treatment.
Objectives: To study the clinical outcome, treatment
response, T-cell subsets and functional consequences of a
novel tumour necrosis factor (TNF) receptor type 1
(TNFRSF1A) mutation affecting the receptor
cleavage site.
Methods: Patients with symptoms suggestive of tumour
necrosis factor receptor-associated periodic syndrome
(TRAPS) and 22 healthy controls (HC) were screened for
mutations in the TNFRSF1A gene. Soluble TNFRSF1A and
inflammatory cytokines were measured by ELISAs.
TNFRSF1A shedding was examined by stimulation of
peripheral blood mononuclear cells (PBMCs) with phorbol
12-myristate 13-acetate followed by flow cytometric
analysis (FACS). Apoptosis of PBMCs was studied by
stimulation with TNFa in the presence of cycloheximide
and annexin V staining. T cell phenotypes were monitored
by FACS.
Results: TNFRSF1A sequencing disclosed a novel V173D/
p.Val202Asp substitution encoded by exon 6 in one
family, the c.194–14G.A splice variant in another and
the R92Q/p.Arg121Gln substitution in two families.
Cardiovascular complications (lethal heart attack and
peripheral arterial thrombosis) developed in two V173D
patients. Subsequent etanercept treatment of the V173D
carriers was highly effective over an 18-month follow-up
period. Serum TNFRSF1A levels did not differ between
TRAPS patients and HC, while TNFRSF1A cleavage from
monocytes was significantly reduced in V173D and R92Q
patients. TNFa-induced apoptosis of PBMCs and T-cell
senescence were comparable between V173D patients
and HC.
Conclusions: The TNFRSF1A V173D cleavage site
mutation may be associated with an increased risk for
cardiovascular complications and shows a strong
response to etanercept. T-cell senescence does not seem
to have a pathogenetic role in affected patients
Local expert experiences and perceptions of environmentally induced migration from Bangladesh to India
This study investigates local expert perceptions of the role of environmental factors, especially in terms of contemporary climate change, in population movements from Bangladesh to India. The aim is to delve into locally held understandings of the phenomenon and to gain a better understanding of these migration processes, which are actively intertwined with local experiences. Both Indian and Bangladeshi experts were interviewed using semi-structured, in-depth interviews in order to explore insights from locally held perceptions and understandings of contextual factors. In total, 10 Bangladeshi and 15 Indian experts were interviewed, covering different disciplines, sectors, regions and job types, together providing a more complete and grounded picture of views of environmentally induced migration in Bangladesh and India. The results show that climate change is perceived by local experts as one of the key factors influencing migration in Bangladesh, both internally and externally. The interviewees, however, placed environmentally induced migration in a broader context of labour and economic migration. In particular, migration for environmental reasons in Bangladesh was evident long before the emergence of climate change as an issue. According to the interviewed experts, this does not preclude increased environmentally induced migration within and from Bangladesh in the future, but its analyses ought to be placed in historical and economical contexts
Development and evaluation of double locus sequence typing for molecular epidemiological investigations of Clostridium difficile.
Despite the development of novel typing methods based on whole genome sequencing, most laboratories still rely on classical molecular methods for outbreak investigation or surveillance. Reference methods for Clostridium difficile include ribotyping and pulsed-field gel electrophoresis, which are band-comparing methods often difficult to establish and which require reference strain collections. Here, we present the double locus sequence typing (DLST) scheme as a tool to analyse C. difficile isolates. Using a collection of clinical C. difficile isolates recovered during a 1-year period, we evaluated the performance of DLST and compared the results to multilocus sequence typing (MLST), a sequence-based method that has been used to study the structure of bacterial populations and highlight major clones. DLST had a higher discriminatory power compared to MLST (Simpson's index of diversity of 0.979 versus 0.965) and successfully identified all isolates of the study (100 % typeability). Previous studies showed that the discriminatory power of ribotyping was comparable to that of MLST; thus, DLST might be more discriminatory than ribotyping. DLST is easy to establish and provides several advantages, including absence of DNA extraction [polymerase chain reaction (PCR) is performed on colonies], no specific instrumentation, low cost and unambiguous definition of types. Moreover, the implementation of a DLST typing scheme on an Internet database, such as that previously done for Staphylococcus aureus and Pseudomonas aeruginosa ( http://www.dlst.org ), will allow users to easily obtain the DLST type by submitting directly sequencing files and will avoid problems associated with multiple databases
Correction: Absence of Zika virus among pregnant women in Vietnam in 2008.
International audienc
Household flood risk reduction in the Czech Republic
This paper uses household surveys in the Bečva River Basin, the Czech Republic to determine the coping and adaptation measures that are implemented for flood risk reduction. In 2012, door-to-door surveys with household residents (N = 304) were completed in areas of high, low, and ostensibly no flood risk. Using a probit model as a regression technique through the statistical software STATA, we explored factors that potentially influence coping and adaptation. Overall, coping and adaptation measures for flooding were not undertaken extensively and the rate of change to adopt measures was slow, even amongst flood-affected households. More work is needed to understand the reasons behind their reticence, especially to confirm how much financial factors are a limiting agent. The regression analysis indicated that more children and more men in the household supported the adoption of adaptation measures. As well, when people perceive that they live in a low or high flood risk zone, the likelihood of taking some adaptation measurements increases compared with the perception of living in a no flood risk zone. Meanwhile, the highest negative correlation was that living in a house elevated off the ground decreases the likelihood of taking other adaptation measurements by 20 %. © 2013 Springer Science+Business Media Dordrecht
Viewpoint paper. Islander mobilities: any change from climate change?
Climate change is stated as being likely to cause the forced movement of millions of people, especially from small island communities. Such statements are not always placed in wider and deeper understandings of mobility and non-mobility. Focusing on island communities, this paper assesses some of the implications inherent in mobility and non-mobility choices related to climate change in comparison to other factors and drivers. Culture and networks are examples of drivers demonstrating that it is not the norm for climate change to dominate mobility and non-mobility choices by islanders. Instead, choices often arise from social factors which, in turn, impact how climate change is and is not addressed. Without denying the major challenges which climate change has previously brought to some islanders and brings to many islanders today, climate change nonetheless brings little substantive change to discussions of islander mobilities
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Discovery and saturation analysis of cancer genes across 21 tumor types
Summary While a few cancer genes are mutated in a high proportion of tumors of a given type (>20%), most are mutated at intermediate frequencies (2–20%). To explore the feasibility of creating a comprehensive catalog of cancer genes, we analyzed somatic point mutations in exome sequence from 4,742 tumor-normal pairs across 21 cancer types. We found that large-scale genomic analysis can identify nearly all known cancer genes in these tumor types. Our analysis also identified 33 genes not previously known to be significantly mutated, including genes related to proliferation, apoptosis, genome stability, chromatin regulation, immune evasion, RNA processing and protein homeostasis. Down-sampling analysis indicates that larger sample sizes will reveal many more genes, mutated at clinically important frequencies. We estimate that near-saturation may be achieved with 600–5000 samples per tumor type, depending on background mutation rate. The results help guide the next stage of cancer genomics
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