2,131 research outputs found
Anharmonic mixing in a magnetic trap
We have experimentally observed re-equilibration of a magnetically trapped
cloud of metastable neon atoms after it was put in a non-equilibrium state.
Using numerical simulations we show that anharmonic mixing, equilibration due
to the collisionless dynamics of atoms in a magnetic trap, is the dominant
process in this equilibration. We determine the dependence of its time on trap
parameters and atom temperature. Furthermore we observe in the simulations a
resonant energy exchange between the radial and axial trap dimensions at a
ratio of trap frequencies \omega_r / \omega_z = 3/2. This resonance is
explained by a simple oscillator model.Comment: 9 pages, 6 figure
Coenzyme Q10 dose-escalation study in hemodialysis patients: safety, tolerability, and effect on oxidative stress.
BackgroundCoenzyme Q10 (CoQ10) supplementation improves mitochondrial coupling of respiration to oxidative phosphorylation, decreases superoxide production in endothelial cells, and may improve functional cardiac capacity in patients with congestive heart failure. There are no studies evaluating the safety, tolerability and efficacy of varying doses of CoQ10 in chronic hemodialysis patients, a population subject to increased oxidative stress.MethodsWe performed a dose escalation study to test the hypothesis that CoQ10 therapy is safe, well-tolerated, and improves biomarkers of oxidative stress in patients receiving hemodialysis therapy. Plasma concentrations of F2-isoprostanes and isofurans were measured to assess systemic oxidative stress and plasma CoQ10 concentrations were measured to determine dose, concentration and response relationships.ResultsFifteen of the 20 subjects completed the entire dose escalation sequence. Mean CoQ10 levels increased in a linear fashion from 704 ± 286 ng/mL at baseline to 4033 ± 1637 ng/mL, and plasma isofuran concentrations decreased from 141 ± 67.5 pg/mL at baseline to 72.2 ± 37.5 pg/mL at the completion of the study (P = 0.003 vs. baseline and P < 0.001 for the effect of dose escalation on isofurans). Plasma F2-isoprostane concentrations did not change during the study.ConclusionsCoQ10 supplementation at doses as high as 1800 mg per day was safe in all subjects and well-tolerated in most. Short-term daily CoQ10 supplementation decreased plasma isofuran concentrations in a dose dependent manner. CoQ10 supplementation may improve mitochondrial function and decrease oxidative stress in patients receiving hemodialysis.Trial registrationThis clinical trial was registered on clinicaltrials.gov [NCT00908297] on May 21, 2009
Can Europe recover without credit?
Data from 135 countries covering five decades suggests that creditless recoveries, in which
the stock of real credit does not return to the pre-crisis level for three years after the GDP
trough, are not rare and are characterised by remarkable real GDP growth rates: 4.7 percent
per year in middle-income countries and 3.2 percent per year in high-income countries.
However, the implications of these historical episodes for the current European situation are
limited, for two main reasons. First, creditless recoveries are much less common in highincome
countries, than in low-income countries which are financially undeveloped. European
economies heavily depend on bank loans and research suggests that loan supply played a
major role in the recent weak credit performance of Europe. There are reasons to believe that,
despite various efforts, normal lending has not yet been restored. Limited loan supply could
be disruptive for the European economic recovery and there has been only a minor
substitution of bank loans with debt securities. Second, creditless recoveries were associated
with significant real exchange rate depreciation, which has hardly occurred so far in most of
Europe. This stylised fact suggests that it might be difficult to re-establish economic growth
in the absence of sizeable real exchange rate depreciation, if credit growth does not return
Approaching Bose-Einstein condensation of metastable neon:Over 10<sup>9</sup> trapped atoms
We present an experimental study of the loading of a magneto-optical trap (MOT) from a brightened and slowed beam of metastable neon atoms. The unprecedented high numbers of 9×10920Ne and 3×109 22Ne metastable atoms are trapped under unconventional trap conditions as compared to metastable helium traps, such as low intensity and small detuning. These cause the MOT to have an extraordinarily large volume on the order of 1cm3 and a typical peak density of 1010 atoms/cm3. A simple Doppler model is discussed which explains why the optimum is found under these conditions. The model includes the seventh beam necessary for the last slowing step before loading
The Left Hand Second to Fourth Digit Ratio (2D:4D) Does Not Discriminate World-Class Female Gymnasts from Age Matched Sedentary Girls
INTRODUCTION: The second to fourth-digit-ratio (2D:4D), a putative marker of prenatal androgen action and a sexually dimorphic trait, has been suggested to be related with sports performance, although results are not univocal. If this relation exists, it is most likely to be detected by comparing extreme groups on the continuum of sports performance. METHODS: In this study the 2D:4D ratio of world-class elite female artistic gymnasts (n = 129), competing at the 1987 Rotterdam World-Championships was compared to the 2D:4D ratio of sedentary age-matched sedentary girls (n = 129), alongside with other anthropometric characteristics including other sexually dimorphic traits such as an androgyny index (Bayer & Bayley) and Heath-Carter somatotype components (endomorphy, mesomorphy, ectomorphy) using AN(C)OVA. 2D:4D was measured on X-rays of the left hand. RESULTS: Left hand 2D:4D digit ratio in world class elite female gymnasts (0.921±0.020) did not differ significantly from 2D:4D in age-matched sedentary girls (0.924±0.018), either with or without inclusion of potentially confounding covariates such as skeletal age, height, weight, somatotype components or androgyny index. Height (161.9±6.4 cm vs 155.4±6.6 cm p<0.01), weight (53.9±7.6 kg vs 46.2 6.3 kg p<0.01), BMI (20.51±2.41 kg/m(2) vs 19.05±1.56 kg/m(2)), skeletal age (15.2±1.1 y vs 14.5±1.2 y p>0.01), somatotype components (4.0/3.0/2.9 vs 1.7/3.7/3.2 for endomorphy (p<0.01), mesomorphy (p<0.01) and ectomorphy (p<0.05) respectively) all differed significantly between sedentary girls and elite gymnasts. As expressed by the androgyny index, gymnasts have, on average, broader shoulders relative to their hips, compared to the reference sample. Correlations between the 2D:4D ratio and chronological age, skeletal age, and the anthropometric characteristics are low and not significant. CONCLUSION: Although other anthropometric characteristics of sexual dimorphism were significantly different between the two samples, the present study cannot discriminate sedentary girls from world-class female gymnasts by means of the left hand 2D:4D ratio
ASSESSING CLIMATE CHANGE IMPACTS AND ADAPTATION STRATEGIES FOR SMALLHOLDER AGRICULTURAL SYSTEMS IN UGANDA
The debate on whether climate change will impact on peoples\u2019
livelihoods and, hence, the need to act is essentially over and has
instead shifted to the development of strategies needed by different
regions and countries to adapt to climate change effects. However,
there is still scanty information necessary to ably address climate
change related issues. There is a considerable knowledge gap with
respect to climate change impact, vulnerability and adaptation to
increased climate variability and change. In this paper, using the
trade off analysis model, the impact of climate change on
peoples\u2019 livelihoods and possible adaptation strategies to
increase the resilience and sustainability of agricultural systems in
three regions of Uganda (central, Masaka and southwest) are analysed.
The results show that 70-97% of households will be adversely affected
by climate change in Uganda. The southwest will be most affected due to
smaller farm sizes and limited livelihood alternatives. There will be
no positive gains from encroaching on swamps, which is one of the
reported adaptation strategies to climate related stresses. Improving
productivity of important crops (bananas for southwest, and sweet
potatoes and bananas for central region), in addition to adoption of
grade cattle will likely be a better adaptation strategy for climate
change.Le d\ue9bat sur le fait que le changement climatique pourra affecter
le mode de vie des populations et, ainsi la n\ue9cessit\ue9
d\u2019agir est arriv\ue9 et consiste \ue0 d\ue9velopper des
strat\ue9gies en rapport avec les besoins de diff\ue9rentes
r\ue9gions et pays pour l\u2019adaptation aux effets du changement
climatique. Cependant, les informations disponibles sont encore
insuffisantes afin d\u2019adresser correctement les probl\ue8mes y
relatifs. Il existe tant de lacunes sur les connaissances en rapport
avec les impacts du changement climatique, la vuln\ue9rabilit\ue9
et l\u2019adaptation \ue0 la variabilit\ue9 et changement
climatique accrus. En utilisant le mod\ue8le du trade off analysis,
cet article a analys\ue9 l\u2019impact du changement climatique sur
le mode de vie des populations et des strat\ue9gies possibles
d\u2019adaptation, afin d\u2019am\ue9liorer la r\ue9silience et
la durabilit\ue9 des syst\ue8mes culturaux dans les trois
r\ue9gions de l\u2019Ouganda (Centre, Masaka et sud- ouest). Les
r\ue9sultats montrent que 70-97% des m\ue9nages seront touch\ue9s
par des effets du changement climatique en Ouganda. Le sud-ouest sera
le plus affect\ue9 par suite de tailles petites de ses exploitations
et son mode de vie \ue0 moyens alternatifs limit\ue9s.
L\u2019invasion des marais ne rapportera aucun gain positif qui est
une des strat\ue9gies d\u2019adaptation indiqu\ue9es au stress
climatique relatif. L\u2019am\ue9lioration de la productivit\ue9
des cultures importantes (bananiers au Sud-ouest, et les patates douces
et le bananier dans la r\ue9gion centrale) en plus de
l\u2019adoption des vaches am\ue9lior\ue9es pourra serait une
meilleur strat\ue9gie d\u2019adaptation au changement climatique
Project 8 Phase III Design Concept
We present a working concept for Phase III of the Project 8 experiment,
aiming to achieve a neutrino mass sensitivity of ( C.L.)
using a large volume of molecular tritium and a phased antenna array. The
detection system is discussed in detail.Comment: 3 pages, 3 figures, Proceedings of Neutrino 2016, XXVII International
Conference on Neutrino Physics and Astrophysics, 4-9 July 2016, London, U
Results from the Project 8 phase-1 cyclotron radiation emission spectroscopy detector
The Project 8 collaboration seeks to measure the absolute neutrino mass scale
by means of precision spectroscopy of the beta decay of tritium. Our technique,
cyclotron radiation emission spectroscopy, measures the frequency of the
radiation emitted by electrons produced by decays in an ambient magnetic field.
Because the cyclotron frequency is inversely proportional to the electron's
Lorentz factor, this is also a measurement of the electron's energy. In order
to demonstrate the viability of this technique, we have assembled and
successfully operated a prototype system, which uses a rectangular waveguide to
collect the cyclotron radiation from internal conversion electrons emitted from
a gaseous Kr source. Here we present the main design aspects of the
first phase prototype, which was operated during parts of 2014 and 2015. We
will also discuss the procedures used to analyze these data, along with the
features which have been observed and the performance achieved to date.Comment: 3 pages; 2 figures; Proceedings of Neutrino 2016, XXVII International
Conference on Neutrino Physics and Astrophysics, 4-9 July 2016, London, U
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