349 research outputs found
THIAMINE IN FISH AND ITS DEGRADATION DURING THERMAL PROCESSING OF SALTED-BOILED FISH
The existence of different forms of thiamine in the llesh of rainbow trout (Salmo gairdneri) and their losses during thermal processing have been investigated
Synthesis, morphology and properties of segmented poly(ether ester amide)s comprising uniform glycine or ÎČ-alanine extended bisoxalamide hard segments
Segmented poly(ether ester amide)s comprising glycine or ÎČ-alanine extended bisoxalamide hard segments are highly phase separated thermoplastic elastomers with a broad temperature independent rubber plateau. These materials with molecular weights, Mn, exceeding 30 Ă 103 g molâ1 are conveniently prepared by polycondensation of preformed bisesterâbisoxalamides and commercially available PTHF diols. FT-IR revealed strongly hydrogen bonded and highly ordered bisoxalamide hard segments with degrees of ordering between 73 and 99%. The morphology consists of fiber-like nano-crystals randomly dispersed in the soft polymer matrix. The micro-structural parameters of the copolymers were addressed by simultaneous small- and wide-angle X-ray scattering. It is shown that the crystals have strictly identical thickness, which is close to the contour length of the hard segment. The long dimension of the crystals is identified with the direction of the hydrogen bonds. The melting transitions of the hard segments are sharp, with temperatures up to 170 °C. The studied polymers have an elastic modulus in the range of 139â170 MPa, a stress at break in the range of 19â31 MPa combined with strains at break of higher than 800%. The segmented copolymer comprising the ÎČ-alanine based bisoxalamide hard segment with a spacer of 6 methylene groups has a melting transition of 141 °C which is higher than the melting transition of its glycine analogue of 119 °C. Likewise, the fracture stress increased from 22 to 31 MPa when the glycine ester group in the hard segment was replaced with ÎČ-alanine. The improved thermal and mechanical properties of the latter polymers is related to the crystal packing of the ÎČ-alanine based hard segments in the copolymer compared to the packing of the hard segments comprising glycine ester group
Averaging Robertson-Walker Cosmologies
The cosmological backreaction arises when one directly averages the Einstein
equations to recover an effective Robertson-Walker cosmology, rather than
assuming a background a priori. While usually discussed in the context of dark
energy, strictly speaking any cosmological model should be recovered from such
a procedure. We apply the Buchert averaging formalism to linear
Robertson-Walker universes containing matter, radiation and dark energy and
evaluate numerically the discrepancies between the assumed and the averaged
behaviour, finding the largest deviations for an Einstein-de Sitter universe,
increasing rapidly with Hubble rate to a 0.01% effect for h=0.701. For the LCDM
concordance model, the backreaction is of the order of Omega_eff~4x10^-6, with
those for dark energy models being within a factor of two or three. The impacts
at recombination are of the order of 10^-8 and those in deep radiation
domination asymptote to a constant value. While the effective equations of
state of the backreactions in Einstein-de Sitter, concordance and quintessence
models are generally dust-like, a backreaction with an equation of state
w_eff<-1/3 can be found for strongly phantom models.Comment: 18 pages, 11 figures, ReVTeX. Updated to version accepted by JCA
Contribution de la culture des foraminifÚres benthiques à la calibration de proxies paléocéanographiques
Grùce aux connaissances acquises sur les conditions idéales de culture de différentes espÚces de foraminifÚres benthiques, il est désormais possible de réaliser des calibrations de proxies paléocéanographiques en laboratoire. Plusieurs expériences ont déjà été réalisées :
1) Calibration du ÎŽ18O de foraminifĂšres benthiques profonds (Barras et al., 2010)
La culture de Bulimina marginata en conditions contrĂŽlĂ©es Ă diffĂ©rentes tempĂ©ratures (4 Ă 19°C) a permis de dĂ©montrer que lâeffet de la tempĂ©rature sur le ÎŽ18O de cette espĂšce est semblable Ă lâeffet thermodynamique enregistrĂ© pour la calcite inorganique. Nous avons pu mettre en Ă©vidence Ă©galement un effet ontogĂ©nĂ©tique non nĂ©gligeable pour les Ă©tudes de reconstitutions palĂ©oclimatiques.
2) Calibration du Mg/Ca de coquilles de Hyalinea balthica (Rosenthal et al., 2011)
La calcification de nouvelles loges de H. balthica Ă diffĂ©rentes tempĂ©ratures (8, 10 et 13°C) a permis de mesurer, Ă lâaide de lâablation laser ICP-MS, un effet dâenviron 12%/°C sur la concentration en Mg/Ca. Ces rĂ©sultats confirment la calibration in situ rĂ©alisĂ©e pour cette espĂšce qui se trouve avoir une sensibilitĂ© 4 fois supĂ©rieure Ă celle des autres espĂšces benthiques profondes.
3) Effet de la salinitĂ© sur le ÎŽ18O, le Mg/Ca et le Sr/Ca dâune espĂšce cĂŽtiĂšre (Diz et al., 2012)
La culture dâAmmonia tepida en conditions contrĂŽlĂ©es Ă diffĂ©rentes salinitĂ©s (29.8, 32.2, 35.5) nâa pas montrĂ© dâeffet significatif de ce paramĂštre sur la composition isotopique et en Ă©lĂ©ments traces de la calcite. Par contre, ces expĂ©riences ont permis de mettre en Ă©vidence un effet de la taille des individus sur la composition en Sr/Ca et une forte variabilitĂ© des mesures de Mg/Ca entre les coquilles dâindividus ayant calcifiĂ© dans les mĂȘmes conditions.
4) Effet de la nourriture sur le ÎŽ13C dâespĂšces intertidales (Mojtahid et al., 2011)
Des expĂ©riences menĂ©es en laboratoire sur des coquilles adultes de Hyanesina germanica et A. beccarii avec de la nourriture labĂ©lisĂ©e radioactivement (3H et 14C) ont montrĂ© que trĂšs peu de carbone ingĂ©rĂ© est incorporĂ© dans la coquille. Cependant, aucun des spĂ©cimens nâa formĂ© de nouvelles loges pendant les expĂ©riences ce qui ne permet pas une conclusion dĂ©finitive sur lâinfluence de la nourriture sur la signature isotopique de la calcite. Ceci ouvre les portes Ă dâautres expĂ©riences sur des juvĂ©niles avec le mĂȘme protocole qui sâest avĂ©rĂ© trĂšs appropriĂ©.
Ces Ă©tudes ont dĂ©montrĂ© lâutilitĂ© de rĂ©aliser des calibrations de proxies en laboratoire. Nous prĂ©voyons de poursuivre ce travail en travaillant au dĂ©veloppement de nouveaux proxies de palĂ©o-oxygĂ©nation grĂące au programme de recherche rĂ©gional MADONA
An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics
For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types
Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in âs = 7 TeV pp collisions with the ATLAS detector
A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fbâ1 of protonâproton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results
Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC
Measurements of inclusive jet suppression in heavy ion collisions at the LHC
provide direct sensitivity to the physics of jet quenching. In a sample of
lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated
luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with
a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the
transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the
anti-kt algorithm with values for the distance parameter that determines the
nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of
the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp.
Jet production is found to be suppressed by approximately a factor of two in
the 10% most central collisions relative to peripheral collisions. Rcp varies
smoothly with centrality as characterized by the number of participating
nucleons. The observed suppression is only weakly dependent on jet radius and
transverse momentum. These results provide the first direct measurement of
inclusive jet suppression in heavy ion collisions and complement previous
measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables,
submitted to Physics Letters B. All figures including auxiliary figures are
available at
http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02
Driver Fusions and Their Implications in the Development and Treatment of Human Cancers.
Gene fusions represent an important class of somatic alterations in cancer. We systematically investigated fusions in 9,624 tumors across 33 cancer types using multiple fusion calling tools. We identified a total of 25,664 fusions, with a 63% validation rate. Integration of gene expression, copy number, and fusion annotation data revealed that fusions involving oncogenes tend to exhibit increased expression, whereas fusions involving tumor suppressors have the opposite effect. For fusions involving kinases, we found 1,275 with an intact kinase domain, the proportion of which varied significantly across cancer types. Our study suggests that fusions drive the development of 16.5% of cancer cases and function as the sole driver in more than 1% of them. Finally, we identified druggable fusions involving genes such as TMPRSS2, RET, FGFR3, ALK, and ESR1 in 6.0% of cases, and we predicted immunogenic peptides, suggesting that fusions may provide leads for targeted drug and immune therapy
The performance of the jet trigger for the ATLAS detector during 2011 data taking
The performance of the jet trigger for the ATLAS detector at the LHC during the 2011 data taking period is described. During 2011 the LHC provided protonâproton collisions with a centre-of-mass energy of 7 TeV and heavy ion collisions with a 2.76 TeV per nucleonânucleon collision energy. The ATLAS trigger is a three level system designed to reduce the rate of events from the 40 MHz nominal maximum bunch crossing rate to the approximate 400 Hz which can be written to offline storage. The ATLAS jet trigger is the primary means for the online selection of events containing jets. Events are accepted by the trigger if they contain one or more jets above some transverse energy threshold. During 2011 data taking the jet trigger was fully efficient for jets with transverse energy above 25 GeV for triggers seeded randomly at Level 1. For triggers which require a jet to be identified at each of the three trigger levels, full efficiency is reached for offline jets with transverse energy above 60 GeV. Jets reconstructed in the final trigger level and corresponding to offline jets with transverse energy greater than 60 GeV, are reconstructed with a resolution in transverse energy with respect to offline jets, of better than 4 % in the central region and better than 2.5 % in the forward direction
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