302 research outputs found
Jet energy measurement with the ATLAS detector in proton-proton collisions at root s=7 TeV
The jet energy scale and its systematic uncertainty are determined for jets measured with the ATLAS detector at the LHC in proton-proton collision data at a centre-of-mass energy of âs = 7TeV corresponding to an integrated luminosity of 38 pb-1. Jets are reconstructed with the anti-kt algorithm with distance parameters R=0. 4 or R=0. 6. Jet energy and angle corrections are determined from Monte Carlo simulations to calibrate jets with transverse momenta pTâ„20 GeV and pseudorapidities {pipe}η{pipe}<4. 5. The jet energy systematic uncertainty is estimated using the single isolated hadron response measured in situ and in test-beams, exploiting the transverse momentum balance between central and forward jets in events with dijet topologies and studying systematic variations in Monte Carlo simulations. The jet energy uncertainty is less than 2. 5 % in the central calorimeter region ({pipe}η{pipe}<0. 8) for jets with 60â€pT<800 GeV, and is maximally 14 % for pT<30 GeV in the most forward region 3. 2â€{pipe}η{pipe}<4. 5. The jet energy is validated for jet transverse momenta up to 1 TeV to the level of a few percent using several in situ techniques by comparing a well-known reference such as the recoiling photon pT, the sum of the transverse momenta of tracks associated to the jet, or a system of low-pT jets recoiling against a high-pT jet. More sophisticated jet calibration schemes are presented based on calorimeter cell energy density weighting or hadronic properties of jets, aiming for an improved jet energy resolution and a reduced flavour dependence of the jet response. The systematic uncertainty of the jet energy determined from a combination of in situ techniques is consistent with the one derived from single hadron response measurements over a wide kinematic range. The nominal corrections and uncertainties are derived for isolated jets in an inclusive sample of high-pT jets. Special cases such as event topologies with close-by jets, or selections of samples with an enhanced content of jets originating from light quarks, heavy quarks or gluons are also discussed and the corresponding uncertainties are determined. © 2013 CERN for the benefit of the ATLAS collaboration
Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector
The inclusive and dijet production cross-sections have been measured for jets
containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass
energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The
measurements use data corresponding to an integrated luminosity of 34 pb^-1.
The b-jets are identified using either a lifetime-based method, where secondary
decay vertices of b-hadrons in jets are reconstructed using information from
the tracking detectors, or a muon-based method where the presence of a muon is
used to identify semileptonic decays of b-hadrons inside jets. The inclusive
b-jet cross-section is measured as a function of transverse momentum in the
range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet
cross-section is measured as a function of the dijet invariant mass in the
range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets
and the angular variable chi in two dijet mass regions. The results are
compared with next-to-leading-order QCD predictions. Good agreement is observed
between the measured cross-sections and the predictions obtained using POWHEG +
Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet
cross-section. However, it does not reproduce the measured inclusive
cross-section well, particularly for central b-jets with large transverse
momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final
version published in European Physical Journal
Cystic Echinococcosis in Spain: Current Situation and Relevance for Other Endemic Areas in Europe
Cystic echinococcosis (CE) remains an important health problem in many regions of the world, both where no control measures have been implemented, and where control programs have been incompletely successful with ensuing re-emergence of the disease. In Spain, official data on CE show an increase in the proportion of intermediate hosts with CE during the last few years, and autochthonous pediatric patients have been reported, a sign of active local transmission of disease. A similar picture emerges from data reported to the European Food Safety Authority by other European countries. Nevertheless, several crucial aspects related to CE that would help better understand and control the disease have not been tackled appropriately, in particular the emergence of infection in specific geographical areas. In this respect, while some data are missing, other data are conflicting because they come from different databases. We review the current situation of CE in Spain compared with areas in which similar problems in the CE field exist, and offer recommendations on how to overcome those limitations. Specifically, we believe that the introduction of national registries for CE with online data entry, following the example set by the European Registry for Alveolar Echinococcosis, would help streamline data collection on CE by eliminating the need for evaluating and integrating data from multiple regions, by avoiding duplication of data from patients who access several different health facilities over time, and by providing much needed clinical and epidemiological data that are currently accessible only to clinicians
Role of the Drosophila Non-Visual Ă-Arrestin Kurtz in Hedgehog Signalling
The non-visual Ă-arrestins are cytosolic proteins highly conserved across species that participate in a variety of signalling events, including plasma membrane receptor degradation, recycling, and signalling, and that can also act as scaffolding for kinases such as MAPK and Akt/PI3K. In Drosophila melanogaster, there is only a single non-visual Ă-arrestin, encoded by kurtz, whose function is essential for neuronal activity. We have addressed the participation of Kurtz in signalling during the development of the imaginal discs, epithelial tissues requiring the activity of the Hedgehog, Wingless, EGFR, Notch, Insulin, and TGFÎČ pathways. Surprisingly, we found that the complete elimination of kurtz by genetic techniques has no major consequences in imaginal cells. In contrast, the over-expression of Kurtz in the wing disc causes a phenotype identical to the loss of Hedgehog signalling and prevents the expression of Hedgehog targets in the corresponding wing discs. The mechanism by which Kurtz antagonises Hedgehog signalling is to promote Smoothened internalization and degradation in a clathrin- and proteosomal-dependent manner. Intriguingly, the effects of Kurtz on Smoothened are independent of Gprk2 activity and of the activation state of the receptor. Our results suggest fundamental differences in the molecular mechanisms regulating receptor turnover and signalling in vertebrates and invertebrates, and they could provide important insights into divergent evolution of Hedgehog signalling in these organisms
Seropositivity rates for agents of canine vector-borne diseases in Spain : a multicentre study
Background: Controlling canine vector-borne diseases (CVBD) is a major concern, since some of these diseases are serious zoonoses. This study was designed to determine seropositivity rates in Spain for agents causing the following five CVBD: leishmaniosis (Leishmania infantum: Li), heartworm (Dirofilaria immitis: Di), ehrlichiosis (Ehrlichia canis: Ec), anaplasmosis (Anaplasma phagocytophilum/Anaplasma platys: An) and Lyme disease (Borrelia burgdorferi: Bb). Methods: Anti-An, -Bb, and -Ec antibodies and the Di antigen were determined using the 4DX SNAPÂź Test (IDEXX Laboratories) and anti-L. infantum (Li) antibodies using the Leishmania SNAPÂź Test (IDEXX Laboratories) in blood and/or serum samples. Results: Among 1100 dogs examined, overall seropositivity rates were: Li (15.7%), Ec (5%), An (3.1%), Di (1.25%) and Bb (0.4%). While seropositivity towards Bb and Di was similar in all geographic regions, rates were significantly higher in the east of Spain (8.3%) for An, significantly higher in the north (20%) for Ec, and significantly higher in the Southeast (46.6%) and South (27.4%), and significantly lower in the north (0%) for Li. No statistical associations were observed between sex and the CVBD analyzed (pââ„â0.05) while the following associations with other variables were detected: a higher seropositivity to Ec (40%) and Bb (6.7%) in dogs under one year of age compared with adults (pâ<â0.05); and a higher seropositivity to An and Li in dogs that lived outdoors versus indoors (pâ=â0.01; pâ<â0.001, respectively). Seropositivity rates of 2.1%, 0%, 1.7%, 0.5% and 4.2% were recorded respectively for An, Bb, Ec, Di and Li in dogs with no clinical signs (nâ=â556) versus 3.8%, 0.6%, 7.5%, 1.8% and 25.9% for those with signs (nâ=â507) suggestive of a CVBD. Conclusion: The data obtained indicate a risk for dogs in Spain of acquiring any of the five CVBD examined. Veterinarians in the different regions should include these diseases in their differential diagnoses and recommend the use of repellents and other prophylactic measures to prevent disease transmission by arthropod vectors. Public health authorities also need to become more involved in the problem, since some of the CVBD examined here also affect humans
Biomarker candidates of neurodegeneration in Parkinsonâs disease for the evaluation of disease-modifying therapeutics
Reliable biomarkers that can be used for early diagnosis and tracking disease progression are the cornerstone of the development of disease-modifying treatments for Parkinsonâs disease (PD). The German Society of Experimental and Clinical Neurotherapeutics (GESENT) has convened a Working Group to review the current status of proposed biomarkers of neurodegeneration according to the following criteria and to develop a consensus statement on biomarker candidates for evaluation of disease-modifying therapeutics in PD. The criteria proposed are that the biomarker should be linked to fundamental features of PD neuropathology and mechanisms underlying neurodegeneration in PD, should be correlated to disease progression assessed by clinical rating scales, should monitor the actual disease status, should be pre-clinically validated, and confirmed by at least two independent studies conducted by qualified investigators with the results published in peer-reviewed journals. To date, available data have not yet revealed one reliable biomarker to detect early neurodegeneration in PD and to detect and monitor effects of drug candidates on the disease process, but some promising biomarker candidates, such as antibodies against neuromelanin, pathological forms of α-synuclein, DJ-1, and patterns of gene expression, metabolomic and protein profiling exist. Almost all of the biomarker candidates were not investigated in relation to effects of treatment, validated in experimental models of PD and confirmed in independent studies
The Beaker phenomenon and the genomic transformation of northwest Europe
From around 2750 to 2500 bc, Bell Beaker pottery became widespread across western and central Europe, before it disappeared between 2200 and 1800 bc. The forces that propelled its expansion are a matter of long-standing debate, and there is support for both cultural diffusion and migration having a role in this process. Here we present genome-wide data from 400 Neolithic, Copper Age and Bronze Age Europeans, including 226 individuals associated with Beaker-complex artefacts. We detected limited genetic affinity between Beaker-complex-associated individuals from Iberia and central Europe, and thus exclude migration as an important mechanism of spread between these two regions. However, migration had a key role in the further dissemination of the Beaker complex. We document this phenomenon most clearly in Britain, where the spread of the Beaker complex introduced high levels of steppe-related ancestry and was associated with the replacement of approximately 90% of Britainâs gene pool within a few hundred years, continuing the east-to-west expansion that had brought steppe-related ancestry into central and northern Europe over the previous centuries
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