We report new measurements of atmospheric methane by the Curiosity rover’s Tunable Laser Spectrometer that is part of the Sample Analysis at Mars suite (TLS-SAM), finding nondetections during two ...daytime measurements of average value 0.05 ± 0.22 ppbv (95% confidence interval CI). These are in marked contrast with nighttime background levels of 0.52 ± 0.10 (95% CI) from four measurements taken during the same season of northern summer. This large day-night difference suggests that methane accumulates while contained near the surface at night, but drops below TLS-SAM detection limits during the day, consistent with the daytime nondetection by instruments on board the ExoMars Trace Gas Orbiter. With no evidence for methane production by the rover itself, we propose that the source is one of planetary micro-seepage. Dynamical modeling indicates that such methane release is contained within the collapsed planetary boundary layer (PBL) at night due to a combination of nocturnal inversion and convergent downslope flow winds that confine the methane inside the crater close to the point where it is released. The methane abundance is then diluted during the day through increased vertical mixing associated with a higher altitude PBL and divergent upslope flow that advects methane out of the crater region. We also report detection of a large spike of methane in June 2019 with a mean
in situ
value over a two-hour ingest of 20.5 ± 4 ppbv (95% CI). If near-surface production is occurring widely across Mars, it must be accompanied by a fast methane destruction or sequestration mechanism, or both.
Summary Background Children and young adults treated with total body or abdominal radiotherapy have an increased risk of insulin resistance and diabetes mellitus. However, little is known of the ...effect of pancreas irradiation on the risk of diabetes. We assessed the relation between radiation exposure and occurrence of diabetes in a large cohort of long-term childhood cancer survivors. Methods We sent a questionnaire to 3468 survivors of a childhood cancer treated in eight centres in France and the UK between 1946 and 1985, of which 2520 were returned. Each self-declaration of diabetes was confirmed by contacting the patients' medical doctors. We estimated the radiation dose received by the tail, head, and body of the pancreas and 185 other anatomical sites during each course of radiotherapy from 1990 to 1995 for each child after reconstruction of the conditions in which irradiation was delivered. We investigated the relation between radiation dose to the pancreas and the risk of a subsequent diabetes diagnosis. Findings 65 cases of diabetes were validated. The risk of diabetes increased strongly with radiation dose to the tail of the pancreas, where the islets of Langerhans are concentrated, up to 20–29 Gy and then reached a plateau for higher radiation doses. The estimated relative risk at 1 Gy was 1·61 (95% CI 1·21–2·68). The radiation dose to the other parts of the pancreas did not have a significant effect. Compared with patients who did not receive radiotherapy, the relative risk of diabetes was 11·5 (95% CI 3·9–34·0) in patients who received 10 Gy or more to the tail of the pancreas. Results were unchanged after adjustment for body-mass index, despite its strong independent effect (p<0·0001), and were similar between men and women. Children younger than 2 years at time of radiotherapy were more sensitive to radiation than were older patients (relative risk at 1 Gy 2·1 95% CI 1·4–4·3 vs 1·4 95% CI 1·1–2·2 in older patients; p=0·02 for the difference). For the 511 patients who had received more than 10 Gy to the tail of the pancreas, the cumulative incidence of diabetes was 16% (95% CI 11–24). Interpretation Our study provides evidence of a dose-response relation between radiation exposure of pancreas and subsequent risk of diabetes. Because of the risks observed and the frequency of diabetes in general population, this finding raises important public health issues. The pancreas needs to be regarded as a critical organ when planning radiation therapy, particularly in children. Follow-up of patients who received abdominal irradiation should include diabetes screening. Funding Ligue Nationale Contre le Cancer, Institut de Recherche en Santé Publique, Programme Hospitalier de Recherche Clinique, Institut National du Cancer, Agence Française de Sécurité Sanitaire et des Produits de Santé, Fondation Pfizer pour la santé de l'enfant et de l'adolescent.
The aim of this study was to investigate the role of radiation dose received to the circle of Willis (WC) during radiation therapy (RT) and of potential dose-response modifiers on the risk of stroke ...after treatment of childhood cancer.
We evaluated the risk factors for stroke in a cohort of 3172 5-year survivors of childhood cancer who were followed up for a median time of 26 years. Radiation doses to the WC and brain structures were estimated for each of the 2202 children who received RT.
Fifty-four patients experienced a confirmed stroke; 39 were ischemic. Patients not receiving RT had a stroke risk similar to that of the general population, whereas those who received RT had an 8.5-fold increased risk (95% confidence interval CI: 6.3-11.0). The excess of incidence of stroke increased yearly. The dose of radiation to the WC, rather than to other brain structures, was found to be the best predictor of stroke. The relative risk was 15.7 (95% CI: 4.9-50.2) for doses of 40 Gy or more. At 45 years of age, the cumulative stroke incidence was 11.3% (95% CI: 7.1%-17.7%) in patients who received 10 Gy or more to the WC, compared with 1% expected from general population data. Radiation doses received to the heart and neck also increased the risk. Surgery for childhood brain cancer was linked to hemorrhagic strokes in these patients.
The WC should be considered as a major organ at risk during RT for childhood brain cancers. The incidence of radiation-induced ischemic stroke strongly increases with long-term follow-up.
The results of a search for pair production of supersymmetric partners of the Standard Model third-generation quarks are reported. This search uses 20.1 fb-1 of pp collisions at sqrt{s}=8 TeV ...collected by the ATLAS experiment at the Large Hadron Collider. The lightest bottom and top squarks (b1 and t1 respectively) are searched for in a final state with large missing transverse momentum and two jets identified as originating from b-quarks. No excess of events above the expected level of Standard Model background is found. The results are used to set upper limits on the visible cross section for processes beyond the Standard Model. Exclusion limits at the 95% confidence level on the masses of the third-generation squarks are derived in phenomenological supersymmetric R-parity-conserving models in which either the bottom or the top squark is the lightest squark. The b1 is assumed to decay via b1->b chi0 and the t via t1->b chipm, with undetectable products of the subsequent decay of the chipm due to the small mass splitting between the chipm and the chi0.
The dynamics of isolated-photon plus jet production in pp collisions at a centre-of-mass energy of 7 TeV has been studied with the ATLAS detector at the LHC using an integrated luminosity of 37 pb-1. ...Measurements of isolated-photon plus jet bin-averaged cross sections are presented as functions of photon transverse energy, jet transverse momentum and jet rapidity. In addition, the bin-averaged cross sections as functions of the difference between the azimuthal angles of the photon and the jet, the photon--jet invariant mass and the scattering angle in the photon--jet centre-of-mass frame have been measured. Next-to-leading-order QCD calculations are compared to the measurements and provide a good description of the data, except for the case of the azimuthal opening angle.
The « LACTAFF » program (2012-2015) aimed at improving the control of goat lactic farmhouse cheese ripening, a technology frequently used by farmers, by producing tools and references for producers ...and the technicians guiding them. Surveys conducted in 49 farms in the 6 main regions producing this kind of cheeses allowed to characterize the great diversity of cheeses, premises, equipment and practices, and to link cheese categories with practices, premises characteristics and air production conditions. In laboratory and experimental dairies, the key role of humidity was quantified during ripening and during drying, in which air speed is even more important. Atmospheric parameters effects on cheeses physicochemical composition and sensory characteristics were quantified for one type of cheeses. Specialist experience of cheese technology, premises design and climate control equipment and technician experience were capitalized at the same time. This project led to the writing of technical documents available online and a book about lactic farmhouse cheeses ripening.
Le programme LACTAFF (2012 – 2015) a eu pour objectif d’améliorer la maîtrise de l’affinage des fromages fermiers lactiques, technologie la plus couramment utilisée à la ferme, en fournissant des outils et des références aux producteurs et aux techniciens qui les accompagnent. Des enquêtes menées dans 49 fermes des 6 principales régions produisant ce type de fromage ont permis de caractériser la grande diversité des fromages fabriqués, des locaux, des équipements et des pratiques et d’établir des liens entre les grandes catégories de fromages et les pratiques, locaux et conditions d’ambiance. Par ailleurs, au laboratoire et en fromageries expérimentales, le rôle clé de l’hygrométrie a été quantifié en affinage, ainsi qu’au séchage où la vitesse d’air joue un rôle encore plus important. Les effets des paramètres d’ambiance sur la composition physico-chimique et les caractéristiques sensorielles des fromages ont été quantifiés pour un type de fromage donné.
A measurement of the top quark electric charge is carried out in the ATLAS experiment at the Large Hadron Collider using 2.05 fb-1 of data at a centre-of-mass energy of 7 TeV. In units of the ...elementary electric charge, the top quark charge is determined to be 0.64 +- 0.02 (stat.) +- 0.08 (syst.) from the charges of the top quark decay products in single lepton ttbar candidate events. This excludes models that propose a heavy quark of electric charge --4/3, instead of the Standard Model top quark, with a significance of more than 8 sigma.
A search is presented for production of a heavy up-type quark (t') together with its antiparticle, assuming a significant branching ratio for subsequent decay into a W boson and a b quark. The search ...is based on 4.7 fb^-1 of pp collisions at sqrt(s)=7 TeV recorded in 2011 with the ATLAS detector at the CERN Large Hadron Collider. Data are analyzed in the lepton+jets final state, characterized by a high-transverse-momentum isolated electron or muon, large missing transverse momentum and at least three jets. The analysis strategy relies on the substantial boost of the W bosons in the t't'bar signal when mt'>=400 GeV. No significant excess of events above the Standard Model expectation is observed and the result of the search is interpreted in the context of fourth-generation and vector-like quark models. Under the assumption of a branching ratio BR(t'->Wb)=1, a fourth-generation t' quark with mass lower than 656 GeV is excluded at 95% confidence level. In addition, in light of the recent discovery of a new boson of mass ~126 GeV at the LHC, upper limits are derived in the two-dimensional plane of BR(t'->Wb) versus BR(t'->Ht), where H is the Standard Model Higgs boson, for vector-like quarks of various masses.
A search is presented for new particles decaying to large numbers (7 to greater or equal to 10) of jets, missing transverse momentum and no isolated electrons or muons. This analysis uses 20.3/fb of ...pp collision data at sqrt(s)=8 TeV collected by the ATLAS experiment at the Large Hadron Collider. The sensitivity of the search is enhanced by considering the number of b-tagged jets and the scalar sum of masses of large-radius jets in an event. No evidence is found for physics beyond the Standard Model. The results are interpreted in the context of various simplified supersymmetry-inspired models where gluinos are pair produced, as well as a mSUGRA/CMSSM model.
In several extensions of the Standard Model, the top quark can decay into a bottom quark and a light charged Higgs boson H+, t to bH+, in addition to the Standard Model decay t to bW. Since W bosons ...decay to the three lepton generations equally, while H+ may predominantly decay into tau+nu, charged Higgs bosons can be searched for using the violation of lepton universality in top quark decays. The analysis in this paper is based on 4.6/fb of proton-proton collision data at sqrt(s) = 7 TeV collected by the ATLAS experiment at the Large Hadron Collider. Signatures containing leptons (e or mu) and/or a hadronically decaying tau (tau_had) are used. Event yield ratios between e+tau_had and e+mu, as well as between mu+tau_had and mu+e, final states are measured in the data and compared to predictions from simulations. This ratio-based method reduces the impact of systematic uncertainties in the analysis. No significant deviation from the Standard Model predictions is observed. With the assumption that the branching fraction B(H+ to tau+nu) is 100%, upper limits in the range 3.2%-4.4% can be placed on the branching fraction B(t to bH+) for charged Higgs boson masses m(H+) in the range 90-140 GeV. After combination with results from a search for charged Higgs bosons in ttbar decays using the tau_had+jets final state, upper limits on B(t to bH+) can be set in the range 0.8%-3.4%, for m(H+) in the range 90-160 GeV.
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