160 research outputs found
First report of a Turnip yellows virus in association with the brassica stunting disorder in South Africa
No abstract available.http://apsjournals.apsnet.org/loi/pdisMicrobiology and Plant Patholog
Higher bone resorption excretion in South Asian women vs. White Caucasians and increased bone loss with higher seasonal cycling of vitamin D: Results from the D-FINES cohort study
Few data exist on bone turnover in South Asian women and it is not well elucidated as to whether Western dwelling South Asian women have different bone resorption levels to that of women from European ethnic backgrounds. This study assessed bone resorption levels in UK dwelling South Asian and Caucasian women as well as evaluating whether seasonal variation in 25-hydroxyvitamin D [25(OH)D] is associated with bone resorption in either ethnic group.
Data for seasonal measures of urinary N-telopeptide of collagen (uNTX) and serum 25(OH)D were analysed from n = 373 women (four groups; South Asian postmenopausal n = 44, South Asian premenopausal n = 50, Caucasian postmenopausal n = 144, Caucasian premenopausal n = 135) (mean (Ā± SD) age 48 (14) years; age range 18ā79 years) who participated in the longitudinal D-FINES (Diet, Food Intake, Nutrition and Exposure to the Sun in Southern England) cohort study (2006ā2007).
A mixed between-within subjects ANOVA (n = 192) showed a between subjects effect of the four groups (P < 0.001) on uNTX concentration, but no significant main effect of season (P = 0.163). Bonferroni adjusted Post hoc tests (P ā¤ 0.008) suggested that there was no significant difference between the postmenopausal Asian and premenopausal Asian groups. Season specific age-matched-pairs analyses showed that in winter (P = 0.04) and spring (P = 0.007), premenopausal Asian women had a 16 to 20 nmol BCE/mmol Cr higher uNTX than premenopausal Caucasian women.
The (amplitude/mesor) ratio (i.e. seasonal change) for 25(OH)D was predictive of uNTX, with estimate (SD) = 0.213 (0.015) and 95% CI (0.182, 0.245; P < 0.001) in a non-linear mixed model (n = 154). This showed that individuals with a higher seasonal change in 25(OH)D, adjusted for overall 25(OH)D concentration, showed increased levels of uNTX. Although the effect size was smaller than for the amplitude/mesor ratio, the mesor for 25(OH)D concentration was also predictive of uNTX, with estimate (SD) = ā 0.035 (0.004), and 95% CI (ā 0.043, ā 0.028; P < 0.001).
This study demonstrates higher levels of uNTX in premenopausal South Asian women than would be expected for their age, being greater than same-age Caucasian women, and similar to postmenopausal Asian women. This highlights potentially higher than expected bone resorption levels in premenopausal South Asian women which, if not offset by concurrent increased bone formation, may have future clinical and public health implications which warrant further investigation. Individuals with a larger seasonal change in 25(OH)D concentration showed an increased bone resorption, an association which was larger than that of the 25(OH)D yearly average, suggesting it may be as important clinically to ensure a stable and steady 25(OH)D concentration, as well as one that is high enough to be optimal for bone health
Manipulating mitochondrial dynamics in the NTS prevents diet-induced deficits in brown fat morphology and glucose uptake
Aims
Brown adipose tissue (BAT) can produce heat by metabolizing glucose and fatty acids. Activation of BAT is controlled by the central nervous system (CNS) through sympathetic innervation. Dysregulation of signalling molecules in selective CNS areas such as the nucleus of tractus solitarius (NTS) are linked with altered BAT activity, obesity and diabetes. High-fat diet (HFD)-feeding increases mitochondrial fragmentation in the NTS, triggering insulin resistance, hyperphagia and weight gain. Here we sought to determine whether changes in mitochondrial dynamics in the NTS can affect BAT glucose uptake.
Main methods
Rats received DVC stereotactic surgery for local brain administration of viruses that express mutated Drp1 genes. BAT glucose uptake was measured with PET/CT scans. Biochemical assays and immunohistochemistry determined altered levels of key signalling molecules and neural innervation of BAT.
Key findings
We show that short-term HFD-feeding decreases BAT glucose uptake. However, inhibiting mitochondrial fragmentation in NTS-astrocytes of HFD-fed rats partially restores BAT glucose uptake accompanied by lower blood glucose and insulin levels. Tyrosine Hydroxylase (TH) revealed that rats with inhibited mitochondrial fragmentation in NTS astrocytes had higher levels of catecholaminergic innervation in BAT compared to HFD-fed rats, and did not exhibit HFD-dependent infiltration of enlarged white fat droplets in the BAT. In regular chow-fed rats, increasing mitochondrial fragmentation in the NTS-astrocytes reduced BAT glucose uptake, TH immune-positive boutons and Ī²3-adrenergic receptor levels.
Significance
Our data suggest that targeting mitochondrial dynamics in the NTS-astrocytes could be a beneficial strategy to increase glucose utilization and protect from developing obesity and diabetes
Exciting, Cooling And Vortex Trapping In A Bose-Condensed Gas
A straight forward numerical technique, based on the Gross-Pitaevskii
equation, is used to generate a self-consistent description of
thermally-excited states of a dilute boson gas. The process of evaporative
cooling is then modelled by following the time evolution of the system using
the same equation. It is shown that the subsequent rethermalisation of the
thermally-excited state produces a cooler coherent condensate. Other results
presented show that trapping vortex states with the ground state may be
possible in a two-dimensional experimental environment.Comment: 9 pages, 7 figures. It's worth the wait! To be published in Physical
Review A, 1st February 199
Development of a Prediction Model for Stress Fracture During an Intensive Physical Training Program:The Royal Marines Commandos
Background
Stress fractures (SF) are one of the more severe overuse injuries in military training and therefore knowledge of potential risk factors is needed to assist in developing mitigating strategies.
Purpose
To develop a prediction model for risk of SF in Royal Marines (RM) recruits during an arduous military training program.
Study Design
Cohort study
Methods
1,082 recruits (age range: 16-33 years) enrolled between September 2009 and July 2010, were prospectively followed through the 32-week RM training program. SF diagnosis was confirmed from a positive X-Ray or Magnetic Resonance Imaging (MRI) scan. Potential risk factors assessed at week-1 included recruit characteristics, anthropometric assessment, dietary supplement use, lifestyle habits, fitness assessment, blood samples, 25(OH)D, bone strength as measured by heel Broadband Ultrasound Attention (BUA), history of physical activity, and previous and current food intake. A logistic least absolute shrinkage selection operator (LASSO) regression with 10-fold cross-validation method was used to select potential predictors among 47 candidate variables. Model performance was assessed using measures of discrimination (c-index) and calibration. Bootstrapping was used for internal validation of the developed model and to quantify optimism.
Results
A total of 86 (8%) volunteer recruits presented with at least one SF during training. Twelve variables were identified as the most important risk factors of SF. Variables strongly associated with SF were age, body weight, pre-training weight bearing (WB) exercise, pre-training cycling and childhood intake of milk and milk products. The c-index for the prediction model was 0.73 (optimism-corrected c-index 0.68), which represents the model performance in future volunteers. Although 25(OH)D and VO2max had only a borderline statistical significant association with SF, the inclusion of these factors improved the performance of the model.
Conclusion
These findings will assist in identifying recruits at greater risk of SF during training, and support interventions to mitigate this injury risk. However, external validation of the model is still required.</p
Post-Newtonian SPH calculations of binary neutron star coalescence. II. Binary mass ratio, equation of state, and spin dependence
Using our new Post-Newtonian SPH (smoothed particle hydrodynamics) code, we
study the final coalescence and merging of neutron star (NS) binaries. We vary
the stiffness of the equation of state (EOS) as well as the initial binary mass
ratio and stellar spins. Results are compared to those of Newtonian
calculations, with and without the inclusion of the gravitational radiation
reaction. We find a much steeper decrease in the gravity wave peak strain and
luminosity with decreasing mass ratio than would be predicted by simple
point-mass formulae. For NS with softer EOS (which we model as simple
polytropes) we find a stronger gravity wave emission, with a
different morphology than for stiffer EOS (modeled as polytropes as
in our previous work). We also calculate the coalescence of NS binaries with an
irrotational initial condition, and find that the gravity wave signal is
relatively suppressed compared to the synchronized case, but shows a very
significant second peak of emission. Mass shedding is also greatly reduced, and
occurs via a different mechanism than in the synchronized case. We discuss the
implications of our results for gravity wave astronomy with laser
interferometers such as LIGO, and for theoretical models of gamma-ray bursts
(GRBs) based on NS mergers.Comment: RevTeX, 38 pages, 24 figures, Minor Corrections, to appear in Phys.
Rev.
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Libraries and open society; Popper, Soros and digital information
This paper examines the role of libraries and information services, in promoting the āopen societyā espoused by Karl Popper and George Soros. After a brief discussion of the nature of an āopen societyā, the paper covers the role played by provision of knowledge and information, of new technology, particularly the Internet, and of critical thinking and digital literacy in the development of this form of society. Conclusions are drawn for the role of libraries and librarians, with seven general principles suggested:
ā¢ provision of access to a wide variety of sources without ānegativeā restriction or censorship
ā¢ provision of āpositiveā guidance on sources, based on open and objective criteria
ā¢ a recognition that a āfree flow of informationā though essential, is not sufficient
ā¢ a recognition that provision of factual information, while valuable, is not enough
ā¢ a need for a specific concern for the effect of new ICTs, and the Internet in particular
ā¢ promotion of critical thinking and digital literacy
ā¢ a need for explicit consideration of the ethical values of librarie
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