694 research outputs found
A determination of the molar gas constant R by acoustic thermometry in helium
We have determined the acoustic and microwave frequencies of a misaligned spherical resonator
maintained near the temperature of the triple point of water and filled with helium with carefully
characterized molar mass M = (4.002 6032 ± 0.000 0015) g mol-1, with a relative standard uncertainty
ur(M) = 0.37Ă—10-6. From these data and traceable thermometry we estimate the speed of sound in our
sample of helium at TTPW = 273.16 K and zero pressure to be u0
2 = (945 710.45 ± 0.85) m2 s-2 and
correspondingly deduce the value R = (8.314 4743 ± 0.000 0088) J mol-1 K-1 for the molar gas
constant. We estimate the value k = R/NA = (1.380 6508 ± 0.000 0015) × 10-23 J K-1 for the Boltzmann
constant using the currently accepted value of the Avogadro constant NA. These estimates of R and k,
with a relative standard uncertainty of 1.06 Ă— 10-6, are 1.47 parts in 106 above the values recommended
by CODATA in 2010
Psychopathology in police custody: The role of importation, deprivation and interaction models
People experiencing mental illness are over-represented among police cell detainees, however limited work has sought to investigate the occurrence of psychopathology in police custody. The present study sought to examine the predictive power of personal factors (e.g., history of psychiatric hospitalisation), situational factors (e.g., police cell conditions), and their interactive effects to explain the occurrence of psychopathology in police custody. A total of 150 detainees were recruited from two metropolitan police stations in Melbourne, Australia. Personal factors were significantly associated with psychiatric symptomatology, with situational factors and interaction terms yielding no association. Detainees with preexisting vulnerabilities and those unsatisfied with police cell conditions demonstrated the highest levels of psychopathology. While all detainees experience some difficulties in police cells, it is those with pre-existing vulnerabilities that suffer the most. This may be due to the exacerbation of vulnerabilities by police cell conditions. The implications of these findings for provision of health care services in police cells are discussed
Correlates of criminal victimisation among police cell detainees in Victoria, Australia
People with mental illness are more likely to be crime victims than others; however, little is known about the relationship between offending and victimisation among mentally ill offenders. This study investigated the rates and types of victimisation among people detained in police cells (N = 764), with and without histories of mental illness. Those with mental disorders were 1.56 times (95% CI = 1.11–2.17) more likely to be victims of violent crimes than other detainees. Some subgroups of people with mental disorders were not over-represented as victims, raising the possibility that they were less inclined to report certain types of crimes. Implications are discussed with reference to police practice
Chemical Composition of Agropyron desertorum as Related to Grass Tetany
Grass tetany, a Mg deficiency of ruminants, accounts
for significant economic losses to Western cattlemen during
the spring grazing period on Agropyron desertorum.
This nutritional deficiency may also occur when ruminants
graze other temperate grasses, but the soil-plant-animal
factors leading to the problem are not well understood.
The objective of this study was to provide definitive
data relating seasonal changes in the chemical composition
of forage to the occurrence of grass tetany on semiarid
grasslands.
The field experiment was established on two calcareous
soils where grass tetany had previously occurred. Agropyron
desertorum forage was harvested from both sites
at regular intervals during the spring tetany period in
each of 5 years. The forage samples were analyzed for
mineral elements, N, total water-soluble carbohydrates
(TWSC), higher fatty acids (HFA), ash alkalinity, and
aconitic acid.
High levels of N and HFA, which are known from
other studies to reduce Mg availability to the animal,
coincided with the occurrence of tetany. The low Mg
concentrations measured in the forage probably provided
only marginal levels of available Mg to the grazing
animals. A rapid increase in the ratio of N/TWSC coincided
with the onset of tetany, and may be the primary
factor which indirectly decreases Mg availability and
precipitates the occurrence of tetany. Although the relationship
of the protein/energy imbalance to grass tetany
has been suggested previously, as far as the authors are
aware this is the first time that N/TWSC values obtained
during the growing season have been documented in conjunction
with the occurrence of grass tetany
Seasonal Changes in Trans-aconitate and Mineral Composition of Crested Wheatgrass in Relation to Grass Tetany
Grass tetany (hypomagnesemia) frequently occurs from March through
June in cattle grazing crested wheatgrass in western United States. High levels of trans-aconitate
and/or citrate, K, K/(Ca + Mg) ratios and low Mg in the grass are implicated
in the etiology of the disease. In the moist 1967 season, during periods of "flush"
growth following warming trends, trans-aconitate and K increased while Ca and Mg
decreased in crested wheatgrass. These characteristics may explain the incidence of
grass tetany during periods of "flush" growth. During the dry 1968 season, these
trends were not observed. Growth chamber studies confirmed some of the reasons for
changes in crested wheatgrass composition observed in 1967 and 1968
Hsp70 in mitochondrial biogenesis
The family of hsp70 (70 kilodalton heat shock protein) molecular chaperones plays an essential and diverse role in cellular physiology, Hsp70 proteins appear to elicit their effects by interacting with polypeptides that present domains which exhibit non-native conformations at distinct stages during their life in the cell. In this paper we review work pertaining to the functions of hsp70 proteins in chaperoning mitochondrial protein biogenesis. Hsp70 proteins function in protein synthesis, protein translocation across mitochondrial membranes, protein folding and finally the delivery of misfolded proteins to proteolytic enzymes in the mitochondrial matrix
The relationship of moderate-to-vigorous physical activity to cognitive processing in adolescents: findings from the ALSPAC birth cohort
The aim of this study was to assess the relations of daily moderate-to-vigorous physical activity (MVPA) to cognitive functions in 15-year-old adolescents from the Avon Longitudinal Study of Parents and Children while controlling for aerobic fitness. A sub-sample of 667 adolescents
(M(age) = 15.4 ± 0.16 years; 55 % females) who provided valid data on variables of interest, were used in the analyses. MVPA was objectively assessed using an Actigraph GT1M accelerometer and aerobic fitness was expressed as physical work capacity at the heart rate of 170 beats per minute from a cycle ergometer test. A computerized stop-signal task was used to measure mean reaction time (RT) and standard deviation of RT, as indicators of
cognitive processing speed and variability during an attention and inhibitory control task. MVPA was not significantly related to cognitive processing speed or variability of cognitive performance in hierarchical linear regression models. In simple regression models, aerobic
fitness was negatively related to mean RT on the simple go condition. Our results suggest that aerobic fitness, but not MVPA, was associated with cognitive processing speed under less cognitively demanding task conditions. The results thus indicate a potential global effect of aerobic fitness on cognitive functions in adolescents but this may differ depending on the specific task characteristics
Asymptotic properties of Born-improved amplitudes with gauge bosons in the final state
For processes with gauge bosons in the final state we show how to
continuously connect with a single Born-improved amplitude the resonant region,
where resummation effects are important, with the asymptotic region far away
from the resonance, where the amplitude must reduce to its tree-level form.
While doing so all known field-theoretical constraints are respected, most
notably gauge-invariance, unitarity and the equivalence theorem. The
calculations presented are based on the process , mediated by a
possibly resonant Higgs boson; this process captures all the essential
features, and can serve as a prototype for a variety of similar calculations.
By virtue of massive cancellations the resulting closed expressions for the
differential and total cross-sections are particularly compact.Comment: 23 pages, Latex, 4 Figures, uses axodra
Independent and complementary bio-functional effects of CuO and Ga2O3 incorporated as therapeutic agents in silica- and phosphate-based bioactive glasses
The incorporation of therapeutic-capable ions into bioactive glasses (BGs), either based on silica (SBGs) or phosphate (PBGs), is currently envisaged as a proficient path for facilitating bone regeneration. In conjunction with this view, the single and complementary structural and bio-functional roles of CuO and Ga2O3 (in the 2–5 mol% range) were assessed, by deriving a series of SBG and PBG formulations starting from the parent glass systems, FastOs®BG – 38.5SiO2—36.1CaO—5.6P2O5—19.2MgO—0.6CaF2, and 50.0P2O5—35.0CaO—10.0Na2O—5.0 Fe2O3 (mol%), respectively, using the process of melt-quenching. The inter-linked physico-chemistry – biological response of BGs was assessed in search of bio-functional triggers. Further light was shed on the structural role – as network former or modifier – of Cu and Ga, immersed in SBG and PBG matrices. The preliminary biological performance was surveyed in vitro by quantification of Cu and Ga ion release under homeostatic conditions, cytocompatibility assays (in fibroblast cell cultures) and antibacterial tests (against Staphylococcus aureus). The similar (Cu) and dissimilar (Ga) structural roles in the SBG and PBG vitreous networks governed their release. Namely, Cu ions were leached in similar concentrations (ranging from 10–35 ppm and 50–110 ppm at BG doses of 5 and 50 mg/mL, respectively) for both type of BGs, while the release of Ga ions was 1–2 orders of magnitude lower in the case of SBGs (i.e., 0.2–6 ppm) compared to PBGs (i.e., 9–135 ppm). This was attributed to the network modifier role of Cu in both types of BGs, and conversely, to the network former (SBGs) and network modifier (PBGs) roles of Ga. All glasses were cytocompatible at a dose of 5 mg/mL, while at the same concentration the antimicrobial efficiency was found to be accentuated by the coupled release of Cu and Ga ions from SBG. By collective assessment, the most prominent candidate material for the further development of implant coatings and bone graft substitutes was delineated as the 38.5SiO2—34.1CaO—5.6P2O5—16.2MgO—0.6CaF2—2.0CuO—3.0Ga2O3 (mol%) SBG system, which yielded moderate Cu and Ga ion release, excellent cytocompatibility and marked antibacterial efficacy.publishe
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