921 research outputs found
mixing constraints on FCNC with a non-universal
The BaBar and Belle collaborations have recently reported evidence for
mixing. This measurement provides the first significant
constraint on FCNC in the up-quark sector for non-universal models.
Attributing the observed mixing to new physics, we comment on the
resulting rare and decays. We also show that a CP violating
semileptonic asymmetry as large as is allowed by the experimental
results.Comment: RevTex, 10 pages, 1 figure. Several typoes correcte
A comparison of the nutritional content and price between dairy and non-dairy milks and cheeses in UK supermarkets : a cross sectional analysis
This work is part of the Strategic Research Program 2016–2021 and is supported by the Scottish Government's Rural and Environment Science and Analytical Services Division (RESAS).Peer reviewe
The Higgs resonance shape in gluon fusion: Heavy Higgs effects
We study the influence of two--loop radiative corrections of enhanced
electroweak strength on Higgs production at the LHC. We consider Higgs
production by the gluon fusion mechanism, with the subsequent decay of the
Higgs boson into a pair of Z bosons, and incorporate the resonance shape
corrections up to order . We take into account the
full process and the
background, as well as the subsequent decay of the Z pair into leptons. We also
discuss the theoretical uncertainty related to the use of the equivalence
theorem in this process
Higgs bosons decay into bottom-strange in two Higgs Doublets Models
We analyze the decays within two Higgs Doublet
Models with Natural Flavor Conservation (2HDM) type I and II. It is found that
the Higgs bosons decay into bottom-strange can lead to a branching ratio in the
range for small and rather
light charged Higgs in the 2HDM type I. When \tan\beta \ga 1, one can easily
reach a branching ratio of the order . In 2HDM type II, without
imposing constraint, the situation is the same as in 2HDM type
I. If constraint on charged Higgs mass ( GeV)
is imposed, we obtain in the range --.
A comparison between the rates of and
is made. It is found that in the fermiophobic scenario,
is still the dominant decay mode.Comment: 16 pages, Latex, 6 eps figures, more numerics, conclusion slightly
modified in 2HDMII. Version to be published in PL
LHC sensitivity to the resonance spectrum of a minimal strongly interacting electroweak symmetry breaking sector
We present a unified analysis of the two main production processes of vector
boson pairs at the LHC, VV-fusion and qqbar annihilation, in a minimal strongly
interacting electroweak symmetry breaking sector. Using a unitarized
electroweak chiral Lagrangian formalism and modeling the final V_L V_L strong
rescattering effects by a form factor, we describe qqbar annihilation processes
in terms of the two chiral parameters that govern elastic V_L V_L scattering.
Depending on the values of these two chiral parameters, the unitarized
amplitudes may present resonant enhancements in different angular
momentum-isospin channels. Scanning this two parameter space, we generate the
general resonance spectrum of a minimal strongly interacting electroweak
symmetry breaking sector and determine the regions that can be probed at the
LHC.Comment: Final version to appear in Phys. Rev. D, including a more detailed
exposition and a few more references. Conclusions and results unchanged. 14
pages, 5 figure
A Cross-layer Framework for Multiobjective Performance Evaluation of Wireless Ad Hoc Networks
International audienceIn this paper we address the problem of finding the optimal performance region of a wireless ad hoc network when multiple performance metrics are considered. Our contribution is to propose a novel cross-layer framework for deriving the Pareto optimal performance bounds for the network. These Pareto bounds provide key information for understanding the network behavior and the performance trade-offs when multiple criteria are relevant. Our approach is to take a holistic view of the network that captures the cross-interactions among interference management techniques implemented at various layers of the protocol stack (e.g. routing and resource allocation) and determines the objective functions for the multiple criteria to be optimized. The resulting complex multiobjective optimization problem is then solved by multiobjective search techniques. The Pareto optimal sets for an example sensor network are presented and analyzed when delay, reliability and energy objectives are considered
A Gene Expression Signature of Invasive Potential in Metastatic Melanoma Cells
BACKGROUND: We are investigating the molecular basis of melanoma by defining genomic characteristics that correlate with tumour phenotype in a novel panel of metastatic melanoma cell lines. The aim of this study is to identify new prognostic markers and therapeutic targets that might aid clinical cancer diagnosis and management. PRINCIPAL FINDINGS: Global transcript profiling identified a signature featuring decreased expression of developmental and lineage specification genes including MITF, EDNRB, DCT, and TYR, and increased expression of genes involved in interaction with the extracellular environment, such as PLAUR, VCAN, and HIF1a. Migration assays showed that the gene signature correlated with the invasive potential of the cell lines, and external validation by using publicly available data indicated that tumours with the invasive gene signature were less melanocytic and may be more aggressive. The invasion signature could be detected in both primary and metastatic tumours suggesting that gene expression conferring increased invasive potential in melanoma may occur independently of tumour stage. CONCLUSIONS: Our data supports the hypothesis that differential developmental gene expression may drive invasive potential in metastatic melanoma, and that melanoma heterogeneity may be explained by the differing capacity of melanoma cells to both withstand decreased expression of lineage specification genes and to respond to the tumour microenvironment. The invasion signature may provide new possibilities for predicting which primary tumours are more likely to metastasize, and which metastatic tumours might show a more aggressive clinical course
Multiple sclerosis impairs regional functional connectivity in the cerebellum
AbstractResting-state functional magnetic resonance imaging (rs-fMRI) has been used to study changes in long-range functional brain connectivity in multiple sclerosis (MS). Yet little is known about how MS affects functional brain connectivity at the local level. Here we studied 42 patients with MS and 30 matched healthy controls with whole-brain rs-fMRI at 3T to examine local functional connectivity. Using the Kendall's Coefficient of Concordance, regional homogeneity of blood-oxygen-level-dependent (BOLD)-signal fluctuations was calculated for each voxel and used as a measure of local connectivity. Patients with MS showed a decrease in regional homogeneity in the upper left cerebellar hemisphere in lobules V and VI relative to healthy controls. Similar trend changes in regional homogeneity were present in the right cerebellar hemisphere. The results indicate a disintegration of regional processing in the cerebellum in MS. This might be caused by a functional disruption of cortico-ponto-cerebellar and spino-cerebellar inputs, since patients with higher lesion load in the left cerebellar peduncles showed a stronger reduction in cerebellar homogeneity. In patients, two clusters in the left posterior cerebellum expressed a reduction in regional homogeneity with increasing global disability as reflected by the Expanded Disability Status Scale (EDSS) score or higher ataxia scores. The two clusters were mainly located in Crus I and extended into Crus II and the dentate nucleus but with little spatial overlap. These findings suggest a link between impaired regional integration in the cerebellum and general disability and ataxia
Computing folding pathways between RNA secondary structures
Given an RNA sequence and two designated secondary structures A, B, we describe a new algorithm that computes a nearly optimal folding pathway from A to B. The algorithm, RNAtabupath, employs a tabu semi-greedy heuristic, known to be an effective search strategy in combinatorial optimization. Folding pathways, sometimes called routes or trajectories, are computed by RNAtabupath in a fraction of the time required by the barriers program of Vienna RNA Package. We benchmark RNAtabupath with other algorithms to compute low energy folding pathways between experimentally known structures of several conformational switches. The RNApathfinder web server, source code for algorithms to compute and analyze pathways and supplementary data are available at http://bioinformatics.bc.edu/clotelab/RNApathfinder
Strong Double Higgs Production at the LHC
The hierarchy problem and the electroweak data, together, provide a plausible
motivation for considering a light Higgs emerging as a pseudo-Goldstone boson
from a strongly-coupled sector. In that scenario, the rates for Higgs
production and decay differ significantly from those in the Standard Model.
However, one genuine strong coupling signature is the growth with energy of the
scattering amplitudes among the Goldstone bosons, the longitudinally polarized
vector bosons as well as the Higgs boson itself. The rate for double Higgs
production in vector boson fusion is thus enhanced with respect to its
negligible rate in the SM. We study that reaction in pp collisions, where the
production of two Higgs bosons at high pT is associated with the emission of
two forward jets. We concentrate on the decay mode hh -> WW^(*)WW^(*) and study
the semi-leptonic decay chains of the W's with 2, 3 or 4 leptons in the final
states. While the 3 lepton final states are the most relevant and can lead to a
3 sigma signal significance with 300 fb^{-1} collected at a 14 TeV LHC, the two
same-sign lepton final states provide complementary information. We also
comment on the prospects for improving the detectability of double Higgs
production at the foreseen LHC energy and luminosity upgrades.Comment: 54 pages, 26 figures. v2: typos corrected, a few comments and one
table added. Version published in JHE
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