472 research outputs found
Isotopic analysis of faunal material from South Uist, Western Isles, Scotland
This paper reports on the results from stable isotope analysis of faunal bone collagen from a number of Iron Age
and later sites on the island of South Uist, in the Western Isles, Scotland. This preliminary investigation into the isotopic signatures of the fauna is part of a larger project to model the interaction between humans, animals, and the broader environment in the Western Isles. The results demonstrate that the island fauna data fall within the range of expected results for the UK, with the terrestrial herbivorous diets of cattle and sheep confi rmed. The isotopic composition for pigs suggests that some of these animals had an omnivorous diet, whilst a single red deer value might be suggestive of the consumption of marine foods, such as by grazing on seaweed. However, further analysis is needed in order to verify this anomalous isotopic ratio
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Affective Determinants of Physical Activity: A Conceptual Framework and Narrative Review
The literature on affective determinants of physical activity (PA) is growing rapidly. The present paper aims to provide greater clarity regarding the definition and distinctions among the various affect-related constructs that have been examined in relation to PA. Affective constructs are organized according to the Affect and Health Behavior Framework (AHBF), including: (1) affective response (e.g., how one feels in response to PA behavior) to PA; (2) incidental affect (e.g., how one feels throughout the day, unrelated to the target behavior); (3) affect processing (e.g., affective associations, implicit attitudes, remembered affect, anticipated affective response, and affective judgments); and (4) affectively charged motivational states (e.g., intrinsic motivation, fear, and hedonic motivation). After defining each category of affective construct, we provide examples of relevant research showing how each construct may relate to PA behavior. We conclude each section with a discussion of future directions for research
Effect of stress-triaxiality on void growth in dynamic fracture of metals: a molecular dynamics study
The effect of stress-triaxiality on growth of a void in a three dimensional
single-crystal face-centered-cubic (FCC) lattice has been studied. Molecular
dynamics (MD) simulations using an embedded-atom (EAM) potential for copper
have been performed at room temperature and using strain controlling with high
strain rates ranging from 10^7/sec to 10^10/sec. Strain-rates of these
magnitudes can be studied experimentally, e.g. using shock waves induced by
laser ablation. Void growth has been simulated in three different conditions,
namely uniaxial, biaxial, and triaxial expansion. The response of the system in
the three cases have been compared in terms of the void growth rate, the
detailed void shape evolution, and the stress-strain behavior including the
development of plastic strain. Also macroscopic observables as plastic work and
porosity have been computed from the atomistic level. The stress thresholds for
void growth are found to be comparable with spall strength values determined by
dynamic fracture experiments. The conventional macroscopic assumption that the
mean plastic strain results from the growth of the void is validated. The
evolution of the system in the uniaxial case is found to exhibit four different
regimes: elastic expansion; plastic yielding, when the mean stress is nearly
constant, but the stress-triaxiality increases rapidly together with
exponential growth of the void; saturation of the stress-triaxiality; and
finally the failure.Comment: 35 figures, which are small (and blurry) due to the space
limitations; submitted (with original figures) to Physical Review B. Final
versio
Single Spin Asymmetry in Polarized Proton-Proton Elastic Scattering at GeV
We report a high precision measurement of the transverse single spin
asymmetry at the center of mass energy GeV in elastic
proton-proton scattering by the STAR experiment at RHIC. The was measured
in the four-momentum transfer squared range \GeVcSq, the region of a significant interference between the
electromagnetic and hadronic scattering amplitudes. The measured values of
and its -dependence are consistent with a vanishing hadronic spin-flip
amplitude, thus providing strong constraints on the ratio of the single
spin-flip to the non-flip amplitudes. Since the hadronic amplitude is dominated
by the Pomeron amplitude at this , we conclude that this measurement
addresses the question about the presence of a hadronic spin flip due to the
Pomeron exchange in polarized proton-proton elastic scattering.Comment: 12 pages, 6 figure
High non-photonic electron production in + collisions at = 200 GeV
We present the measurement of non-photonic electron production at high
transverse momentum ( 2.5 GeV/) in + collisions at
= 200 GeV using data recorded during 2005 and 2008 by the STAR
experiment at the Relativistic Heavy Ion Collider (RHIC). The measured
cross-sections from the two runs are consistent with each other despite a large
difference in photonic background levels due to different detector
configurations. We compare the measured non-photonic electron cross-sections
with previously published RHIC data and pQCD calculations. Using the relative
contributions of B and D mesons to non-photonic electrons, we determine the
integrated cross sections of electrons () at 3 GeV/10 GeV/ from bottom and charm meson decays to be = 4.0({\rm
stat.})({\rm syst.}) nb and =
6.2({\rm stat.})({\rm syst.}) nb, respectively.Comment: 17 pages, 17 figure
Measurement of Transverse Single-Spin Asymmetries for Di-Jet Production in Proton-Proton Collisions at GeV
We report the first measurement of the opening angle distribution between
pairs of jets produced in high-energy collisions of transversely polarized
protons. The measurement probes (Sivers) correlations between the transverse
spin orientation of a proton and the transverse momentum directions of its
partons. With both beams polarized, the wide pseudorapidity () coverage for jets permits separation of Sivers functions for the valence
and sea regions. The resulting asymmetries are all consistent with zero and
considerably smaller than Sivers effects observed in semi-inclusive deep
inelastic scattering (SIDIS). We discuss theoretical attempts to reconcile the
new results with the sizable transverse spin effects seen in SIDIS and forward
hadron production in pp collisions.Comment: 6 pages total, 1 Latex file, 3 PS files with figure
Measurement of the Bottom contribution to non-photonic electron production in collisions at =200 GeV
The contribution of meson decays to non-photonic electrons, which are
mainly produced by the semi-leptonic decays of heavy flavor mesons, in
collisions at 200 GeV has been measured using azimuthal
correlations between non-photonic electrons and hadrons. The extracted
decay contribution is approximately 50% at a transverse momentum of GeV/. These measurements constrain the nuclear modification factor for
electrons from and meson decays. The result indicates that meson
production in heavy ion collisions is also suppressed at high .Comment: 6 pages, 4 figures, accepted by PR
Changing patterns of eastern Mediterranean shellfish exploitation in the Late Glacial and Early Holocene: Oxygen isotope evidence from gastropod in Epipaleolithic to Neolithic human occupation layers at the Haua Fteah cave, Libya
The seasonal pattern of shellfish foraging at the archaeological site of Haua Fteah in the Gebel Akhdar, Libya was investigated from the Epipaleolithic to the Neolithic via oxygen isotope (d18O) analyses of the topshell Phorcus (Osilinus) turbinatus. To validate this species as faithful year-round palaeoenvironmental recorder, the intra-annual variability of d18O in modern shells and sea water was analysed and compared with measured sea surface temperature (SST). The shells were found to be good candidates for seasonal shellfish forging studies as they preserve nearly the complete annual SST cycle in their shell d18O with minimal slowing or stoppage of growth. During the terminal Pleistocene Early Epipaleolithic (locally known as the Oranian, with modeled dates of 17.2-12.5 ka at 2sigma probability, Douka et al., 2014), analysis of archaeological specimens indicates that shellfish were foraged year-round. This complements other evidence from the archaeological record that shows that the cave was more intensively occupied in this period than before or afterwards. This finding is significant as the period of the Oranian was the coldest and driest phase of the last glacial cycle in the Gebel Akhdar, adding weight to the theory that the Gebel Akhdar may have served as a refugium for humans in North Africa during times of global climatic extremes. Mollusc exploitation in the Latest Pleistocene and Early Holocene, during the Late Epipaleolithic (locally known as the Capsian, c. 12.7 to 9 ka) and the Neolithic (c. 8.5 to 5.4 ka), occurred predominantly during winter. Other evidence from these archaeological phases shows that hunting activities occurred during the warmer months. Therefore, the timing of Holocene shellfish exploitation in the Gebel Akhdar may have been influenced by the seasonal availability of other resources at these times and possibly shellfish were used as a dietary supplement when other foods were less abundant
The development and assessment of a scale to measure the experience of an anorexic voice in anorexia nervosa
The anorexic voice (AV) is defined as a critical internal dialogue which has been implicated in the
development and maintenance of anorexia nervosa (AN). Systematic research to explore this further
requires a valid and reliable measurement tool. This study aimed to develop and assess the validity of
the Experience of an Anorexic VoicE Questionnaire (EAVE-Q). EAVE-Q items were developed and
checked for face and content validity through cognitive interviews with seven individuals diagnosed
with AN. Participants with a diagnosis of AN (N = 148) completed the EAVE-Q, sociodemographic
questions and measures of mood and quality of life to assess internal consistency and construct
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validity. Forty-nine participants completed the EAVE-Q twice more to assess test-retest reliability.
The EAVE-Q had good face and content validity and good acceptability. Principal axis factoring
resulted in an 18-item scale organised into five domains with high internal consistency (α = .70 to α
= .85). Domains correlated significantly with eating disorder symptoms, psychological distress and
quality of life. The EAVE-Q did not discriminate between participants on the basis of body mass index.
Test-retest reliability was moderate. Although the factor structure of the EAVE-Q requires replication
in other AN samples, the EAVE-Q is the first measure of a critical internal dialogue in AN. It is hoped
that it will aid future research to increase understanding of AN and the continued development of
person-centred treatments
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