2,229 research outputs found

    The Development of the CMS Zero Degree Calorimeters to Derive the Centrality of AA Collisions

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    The centrality of PbPb collisions is derived using correlations from the zero degree calorimeter (ZDC) signal and pixel multiplicity at the Compact Muon Solenoid (CMS) Experiment using data from the heavy ion run in 2010. The method to derive the centrality takes the two-dimensional correlation between the ZDC and pixels and linearizes it for sorting events. The initial method for deriving the centrality at CMS uses the energy deposit in the HF detector, and it is compared to the centrality derived by the correlations in ZDC and pixel multiplicity. This comparison highlights the similarities between the results of both methods in central collisions, as expected, and deviations in the results in peripheral collisions. The ZDC signals in peripheral collisions are selected by low pixel multiplicity to obtain a ZDC neutron spectrum, which is used to effectively gain match both sides of the ZDC

    What is the Total Deuterium Abundance in the Local Galactic Disk?

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    Analyses of spectra obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) satellite, together with spectra from the Copernicus and IMAPS instruments, reveal an unexplained very wide range in the observed deuterium/hydrogen (D/H) ratios for interstellar gas in the Galactic disk beyond the Local Bubble. We argue that spatial variations in the depletion of deuterium onto dust grains can explain these local variations in the observed gas-phase D/H ratios. We present a variable deuterium depletion model that naturally explains the constant measured values of D/H inside the Local Bubble, the wide range of gas-phase D/H ratios observed in the intermediate regime (log N(H I} = 19.2-20.7), and the low gas-phase D/H ratios observed at larger hydrogen column densities. We consider empirical tests of the deuterium depletion hypothesis: (i) correlations of gas-phase D/H ratios with depletions of the refractory metals iron and silicon, and (ii) correlation with the molecular hydrogen rotational temperature. Both of these tests are consistent with deuterium depletion from the gas phase in cold, not recently shocked, regions of the ISM, and high gas-phase D/H ratios in gas that has been shocked or otherwise heated recently. We argue that the most representative value for the total (gas plus dust) D/H ratio within 1 kpc of the Sun is >=23.1 +/- 2.4 (1 sigma) parts per million (ppm). This ratio constrains Galactic chemical evolution models to have a very small deuterium astration factor, the ratio of primordial to total (D/H) ratio in the local region of the Galactic disk, which we estimate to be f_d <= 1.19 +/-0.16 (1 sigma) or <= 1.12 +/- 0.14 (1 sigma) depending on the adopted light element nuclear reaction rates.Comment: 19 pages, 9 figure

    Relationship between body composition, inflammation and lung function in overweight and obese asthma

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    Background: The obese-asthma phenotype is not well defined. The aim of this study was to examine both mechanical and inflammatory influences, by comparing lung function with body composition and airway inflammation in overweight and obese asthma. Methods: Overweight and obese (BMI 28-40 kg/m2) adults with asthma (n = 44) completed lung function assessment and underwent full-body dual energy x-ray absorptiometry. Venous blood samples and induced sputum were analysed for inflammatory markers. Results: In females, android and thoracic fat tissue and total body lean tissue were inversely correlated with expiratory reserve volume (ERV). Conversely in males, fat tissue was not correlated with lung function, however there was a positive association between android and thoracic lean tissue and ERV. Lower body (gynoid and leg) lean tissue was positively associated with sputum %neutrophils in females, while leptin was positively associated with android and thoracic fat tissue in males. Conclusions: This study suggests that both body composition and inflammation independently affect lung function, with distinct differences between males and females. Lean tissue exacerbates the obese-asthma phenotype in females and the mechanism responsible for this finding warrants further investigation

    Studies of the Ability to Hold the Eye in Eccentric Gaze: Measurements in Normal Subjects with the Head Erect

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    We studied the ability to hold the eyes in eccentric horizontal or vertical gaze angles in 68 normal humans, age range 19-56. Subjects attempted to sustain visual fixation of a briefly flashed target located 30 in the horizontal plane and 15 in the vertical plane in a dark environment. Conventionally, the ability to hold eccentric gaze is estimated by fitting centripetal eye drifts by exponential curves and calculating the time constant (t(sub c)) of these slow phases of gazeevoked nystagmus. Although the distribution of time-constant measurements (t(sub c)) in our normal subjects was extremely skewed due to occasional test runs that exhibited near-perfect stability (large t(sub c) values), we found that log10(tc) was approximately normally distributed within classes of target direction. Therefore, statistical estimation and inference on the effect of target direction was performed on values of z identical with log10t(sub c). Subjects showed considerable variation in their eyedrift performance over repeated trials; nonetheless, statistically significant differences emerged: values of tc were significantly higher for gaze elicited to targets in the horizontal plane than for the vertical plane (P less than 10(exp -5), suggesting eccentric gazeholding is more stable in the horizontal than in the vertical plane. Furthermore, centrifugal eye drifts were observed in 13.3, 16.0 and 55.6% of cases for horizontal, upgaze and downgaze tests, respectively. Fifth percentile values of the time constant were estimated to be 10.2 sec, 3.3 sec and 3.8 sec for horizontal, upward and downward gaze, respectively. The difference between horizontal and vertical gazeholding may be ascribed to separate components of the velocity position neural integrator for eye movements, and to differences in orbital mechanics. Our statistical method for representing the range of normal eccentric gaze stability can be readily applied in a clinical setting to patients who were exposed to environments that may have modified their central integrators and thus require monitoring. Patients with gaze-evoked nystagmus can be flagged by comparing to the above established normative criteria

    Letrozole: A Steroid-Free Estrous Synchronization Method

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    Most bovine estrous synchronization protocols utilize progesterone plus estrogen to control ovulation timing. A drug that inhibits estrogen production (Letrozole) may be an alternative, steroid-free synchronization method (not yet commercially available). However, low estrogen can negatively affect the health of follicles/oocytes and impact fertility. To determine its effects, Letrozole was administered intramuscularly while tracking follicle growth and circulating hormones. Letrozole response was variable. Two of three cows experienced delayed luteolysis/ovulation and extended progesterone production. This preliminary data indicates that Letrozole treatment allows normal follicle progression but drug response may vary and little is known about effects on oocyte quality

    Inclusive b-hadron production cross section with muons in pp collisions at s√=7TeV

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    A measurement of the b-hadron production cross section in proton-proton collisions at s√=7TeVs=7TeV is presented. The dataset, corresponding to 85 nb−1, was recorded with the CMS experiment at the LHC using a low-threshold single-muon trigger. Events are selected by the presence of a muon with transverse momentum pμT>6GeVpTμ>6GeV with respect to the beam direction and pseudorapidity |η μ | < 2.1. The transverse momentum of the muon with respect to the closest jet discriminates events containing b hadrons from background. The inclusive b-hadron production cross section is presented as a function of muon transverse momentum and pseudorapidity. The measured total cross section in the kinematic acceptance is σ(pp → b + X → μ + X′) = 1.32 ± 0.01(stat) ± 0.30(syst) ± 0.15(lumi)μb

    Attainment and maintenance of pubertal cyclicity may predict reproductive longevity in beef heifers

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    We hypothesized the manner that heifers achieve puberty may indicate their future reproductive longevity. Heifers with discontinued or delayed cyclicity during puberty attainment may have irregular reproductive cycles, anovulation, and infertility in their first breeding season contributing to a shorter reproductive lifespan. Therefore, plasma progesterone (P4) was measured from weaning to breeding on 611 heifers born 2012–2017 and four pubertal classifications were identified: (1) Early; P4 ≥ 1 ng/ml \u3c March 12 with continued cyclicity, (2) Typical; P4 ≥ 1 ng/ml ≥ March 12 with continued cyclicity, (3) Start-Stop; P4 ≥ 1 ng/ml but discontinued cyclicity, and (4) Non-Cycling; no P4 ≥ 1 ng/ml. Historical herd records indicated that 25% of heifers achieved puberty prior to March 12th in the 10 years prior to the study. Start-Stop and Non-Cycling yearling heifers were lighter indicating reduced growth and reproductive maturity traits compared with Early/Typical heifers. In addition, Non-Cycling/Start-Stop heifers were less responsive to prostaglandin F2 alpha (PGF2α) to initiate estrous behavior and ovulation to be artificially inseminated. Non-Cycling heifers had fewer reproductive tract score-5 and reduced numbers of calves born in the first 21-days-ofcalving during their first breeding season. Within the Start-Stop classification, 50% of heifers reinitiated cyclicity with growth traits and reproductive parameters that were similar to heifers in the Early/Typical classification while those that remained non-cyclic were more similar to heifers in the Non-Cycling group. Thus, heifers with discontinued cyclicity or no cyclicity during puberty attainment had delayed reproductive maturity resulting in subfertility and potentially a shorter reproductive lifespan

    Concurrent habitat and life history influences on effective/census population size ratios in stream-dwelling trout

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    Lower effective sizes (Ne) than census sizes (N) are routinely documented in natural populations, but knowledge of how multiple factors interact to lower Ne/N ratios is often limited. We show how combined habitat and life-history influences drive a 2.4- to 6.1-fold difference in Ne/N ratios between two pristine brook trout (Salvelinus fontinalis) populations occupying streams separated by only 750 m. Local habitat features, particularly drainage area and stream depth, govern trout biomass produced in each stream. They also generate higher trout densities in the shallower stream by favoring smaller body size and earlier age-at-maturity. The combination of higher densities and reduced breeding site availability in the shallower stream likely leads to more competition among breeding trout, which results in greater variance in individual reproductive success and a greater reduction in Ne relative to N. A similar disparity between juvenile or adult densities and breeding habitat availability is reported for other species and hence may also result in divergent Ne/N ratios elsewhere. These divergent Ne/N ratios between adjacent populations are also an instructive reminder for species conservation programs that genetic and demographic parameters may differ dramatically within species

    Transverse-momentum and pseudorapidity distributions of charged hadrons in pp collisions at s√=0.9 and 2.36 TeV

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    This is the publisher's version, also available electronically from http://link.springer.com/article/10.1007%2FJHEP02%282010%29041.Measurements of inclusive charged-hadron transverse-momentum and pseudorapidity distributions are presented for proton-proton collisions at s√=0.9 and 2.36 TeV. The data were collected with the CMS detector during the LHC commissioning in December 2009. For non-single-diffractive interactions, the average charged-hadron transverse momentum is measured to be 0.46 ± 0.01 (stat.) ± 0.01 (syst.) GeV/c at 0.9 TeV and 0.50 ± 0.01 (stat.) ± 0.01 (syst.) GeV/c at 2.36 TeV, for pseudorapidities between --2.4 and +2.4. At these energies, the measured pseudorapidity densities in the central region, dN (ch)/dη|(|η|)<0.5, are 3:48 ± 0:02 (stat.) ± 0.13 (syst.) and 4:47 ± 0:04 (stat.) ± 0.16 (syst.), respectively. The results at 0.9 TeV are in agreement with previous measurements and confirm the expectation of near equal hadron production in p-bar p and pp collisions. The results at 2.36 TeV represent the highest-energy measurements at a particle collider to date

    Measurement of the Λ(0)(b) lifetime in pp collisions at s√=7 TeV

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    This is the publisher's version, also available electronically from http://link.springer.com/article/10.1007%2FJHEP07%282013%29163.A measurement of the Λ(0)(b) lifetime using the decay Λ(0)(b)→J/ψΛ in protonproton collisions at s√=7 TeV is presented. The data set, corresponding to an integrated luminosity of about 5 fb(−1), was recorded with the CMS experiment at the Large Hadron Collider using triggers that selected dimuon events in the J/ψ mass region. The Λ(0)(b) lifetime is measured to be 1.503 ± 0.052 (stat.) ± 0.031 (syst.) ps
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