3,274 research outputs found
HD 174005: another binary classified as lambda Boo
We demonstrate that HD 174005, a star recently classified as belonging to the
lambda Boo group, is in reality a double lined spectroscopic binary; at some
phases, the observed composite spectrum may be similar to that of a single star
with weak metal lines.Comment: Accepted by A&
Investigation into the limits of perturbation theory at low Q^2 using HERA deep inelastic scattering data
A phenomenological study of the final combined HERA data on inclusive deep
inelastic scattering (DIS) has been performed. The data are presented and
investigated for a kinematic range extending from values of the four-momentum
transfer, , above 10 GeV down to the lowest values observable at
HERA of = 0.045 GeV and Bjorken , = 6
10. The data are well described by fits based on perturbative quantum
chromodynamics (QCD) using collinear factorisation and evolution of the parton
densities encompassed in the DGLAP formalism from the highest down to
of a few GeV. The Regge formalism can describe the data up to 0.65 GeV. The complete data set can be described by a new fit
using the ALLM parameterisation. The region between the Regge and the
perturbative QCD regimes is of particular interest.Comment: 38 pages, 13 figure
Can conventional forces really explain the anomalous acceleration of Pioneer 10/11 ?
A conventional explanation of the correlation between the Pioneer 10/11
anomalous acceleration and spin-rate change is given. First, the rotational
Doppler shift analysis is improved. Finally, a relation between the radio beam
reaction force and the spin-rate change is established. Computations are found
in good agreement with observational data. The relevance of our result to the
main Pioneer 10/11 anomalous acceleration is emphasized. Our analysis leads us
to conclude that the latter may not be merely artificial.Comment: 9 pages, no figur
Axes determination for segmented true-coaxial HPGe detectors
A fast method to determine the crystallographic axes of segmented
true-coaxial high-purity germanium detectors is presented. It is based on the
analysis of segment-occupancy patterns obtained by irradiation with radioactive
sources. The measured patterns are compared to predictions for different axes
orientations. The predictions require a simulation of the trajectories of the
charge carriers taking the transverse anisotropy of their drift into account.Comment: 18 pages, 1 table, 31 figures; included background contribution to
the occupancy patterns and systematic uncertainties, results slightly change
Characterization of the first true coaxial 18-fold segmented n-type prototype detector for the GERDA project
The first true coaxial 18-fold segmented n-type HPGe prototype detector
produced by Canberra-France for the GERDA neutrinoless double beta-decay
project was tested both at Canberra-France and at the Max-Planck-Institut fuer
Physik in Munich. The main characteristics of the detector are given and
measurements concerning detector properties are described. A novel method to
establish contacts between the crystal and a Kapton cable is presented.Comment: 21 pages, 16 Figures, to be submitted to NIM
Individualisation of time-motion analysis : a method comparison and case report series
© Georg Thieme Verlag KG. This study compared the intensity distribution of time-motion analysis data, when speed zones were categorized by different methods. 12 U18 players undertook a routine battery of laboratory- and field-based assessments to determine their running speed corresponding to the respiratory compensation threshold (RCT), maximal aerobic speed (MAS), maximal oxygen consumption (vVO 2max ) and maximal sprint speed (MSS). Players match-demands were tracked using 5 Hz GPS units in 22 fixtures (50 eligible match observations). The percentage of total distance covered running at high-speed (%HSR), very-high speed (%VHSR) and sprinting were determined using the following speed thresholds: 1) arbitrary; 2) individualised (IND) using RCT, vVO 2max and MSS; 3) individualised via MAS per se; 4) individualised via MSS per se; and 5) individualised using MAS and MSS as measures of locomotor capacities (LOCO). Using MSS in isolation resulted in 61 % and 39 % of player's % HSR and % VHSR, respectively, being incorrectly interpreted, when compared to the IND technique. Estimating the RCT from fractional values of MAS resulted in erroneous interpretations of % HSR in 50 % of cases. The present results suggest that practitioners and researchers should avoid using singular fitness characteristics to individualise the intensity distribution of time-motion analysis data. A combination of players' anaerobic threshold, MAS, and MSS characteristics are recommended to individualise player-tracking data
A Stellar Rotation Census of B Stars: from ZAMS to TAMS
Two recent observing campaigns provide us with moderate dispersion spectra of
more than 230 cluster and 370 field B stars. Combining them and the spectra of
the B stars from our previous investigations (430 cluster and 100
field B stars) yields a large, homogeneous sample for studying the rotational
properties of B stars. We derive the projected rotational velocity ,
effective temperature, gravity, mass, and critical rotation speed for each star. We find that the average is significantly lower
among field stars because they are systematically more evolved and spun down
than their cluster counterparts. The rotational distribution functions of
for the least evolved B stars show that lower mass B
stars are born with a larger proportion of rapid rotators than higher mass B
stars. However, the upper limit of that may separate
normal B stars from emission line Be stars (where rotation promotes mass loss
into a circumstellar disk) is smaller among the higher mass B stars. We compare
the evolutionary trends of rotation (measured according to the polar gravity of
the star) with recent models that treat internal mixing. The spin-down rates
observed in the high mass subset () agree with predictions, but
the rates are larger for the low mass group (). The faster spin
down in the low mass B stars matches well with the predictions based on
conservation of angular momentum in individual spherical shells. Our results
suggest the fastest rotators (that probably correspond to the emission line Be
stars) are probably formed by evolutionary spin up (for the more massive stars)
and by mass transfer in binaries (for the full range of B star masses).Comment: 44 pages, 10 figures, accepted for publication in Ap
Coping with multiple adversities: Men who sought medico-legal care because of physical violence from a partner or ex-partner.
Objectives: To describe male victims of physical violence by an intimate partner who consulted a medico-legal unit, and information available on their perpetrators; to characterize the violent events and their contexts. Little research exists on male victims of physical intimate partner violence seeking medical care. Method: Based on Heise’s ecological framework, mixed methods were used to analyze quantitative and qualitative data collected during 122 medico-legal consultations attended by 115 men who sustained physical violence by an intimate partner from 2006–2012. Results: Quantitative and quantitative data collected from male victims concurred in showing that many of such victims, as well as their partners, faced at the time of the assault multiple adversities and challenges at individual and relationship levels. Among male victims, 26% had no paid job. Among perpetrators, 34% were third-country nationals subject to restricted residence permits. Health issues, worries about money or work combined with complex and conflictive family situations were often in the background of violent events. In a few cases, however, male victims reported no other problems than their partner’s assault. Conclusions: Our findings point out gender-specific aspects of female-to-male physical partner violence. The most common feature is that violence was experienced as one among several adversities. Even though wounds sustained by male victims were not necessarily severe, their emotional suffering was frequent. When underage children were involved, their situation was particularly noteworthy. Interventions with male victims of intimate partner violence should include protection of minors as a priority and as an incentive for fathers to seek help
THE RELATIONSHIP BETWEEN MUSCULOSKELETAL STRENGTH, PHYSIOLOGICAL CHARACTERISTICS, AND KNEE KINESTHESIA FOLLOWING FATIGUING EXERCISE
Fatiguing exercise may result in impaired functional joint stability and increased risk of unintentional injury. While there are several musculoskeletal and physiological characteristics related to fatigue onset, their relationship with proprioceptive changes following fatigue has not been examined. The purpose of this study was to establish the relationship between musculoskeletal and physiological characteristics and changes in proprioception, measured by threshold to detect passive motion (TTDPM), following fatiguing exercise. Twenty, physically active females participated (age: 28.65 ± 5.6 years, height: 165.6 ± 4.3 cm, weight: 61.8 ± 8.0 kg, BMI: 22.5± 2.3 kg/m2, BF: 23.3 ± 5.4%). During Visit 1, subjects completed an exercise history and 24-hour dietary questionnaire, and body composition, TTDPM familiarization, isokinetic knee strength, and maximal oxygen uptake/lactate threshold assessments. During Visit 2, subjects completed TTDPM and isometric knee strength testing prior to and following a fatiguing exercise protocol. Wilcoxon signed rank tests determined TTDPM and isometric knee strength changes from pre- to post- fatigue. Spearman’s rho correlation coefficients determined the relationship between strength and physiological variables with pre- to post-fatigue changes in TTDPM and with pre-fatigue and post-fatigue TTDPM in extension and flexion (α=0.05). No significant differences were demonstrated from pre-fatigue to post-fatigue TTDPM despite a significant decrease in isometric knee flexion strength (P<0.01) and flexion/extension ratio (P<0.05) following fatigue. No significant correlations were observed between strength or physiological variables and changes in TTDPM from pre- to post-fatigue in extension or flexion. Flexion/extension ratio was significantly correlated with pre-fatigue TTDPM in extension (r=-0.231, P<0.05). Peak oxygen uptake was significantly correlated with pre-fatigue (r=-0.500, P<0.01) and post-fatigue (r=-0.520, P<0.05) TTDPM in extension. No significant relationships were demonstrated between musculoskeletal and physiological characteristics and changes in TTDPM following fatigue. The results suggest that highly trained individuals may have better proprioception, and that the high fitness level of subjects in this investigation may have contributed to absence of TTDPM deficits following fatigue despite reaching a high level of perceptual and physiological fatigue. Future studies should consider various subject populations, other musculoskeletal strength characteristics, and different modalities of proprioception to determine the most important contributions to proprioceptive changes following fatigue
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