Quantitative study of quasi-one-dimensional Bose gas experiments via the stochastic Gross-Pitaevskii equation

The stochastic Gross-Pitaevskii equation is shown to be an excellent model for quasi-one-dimensional Bose gas experiments, accurately reproducing the in situ density profiles recently obtained in the experiments of Trebbia et al. [Phys. Rev. Lett. 97, 250403 (2006)] and van Amerongen et al. [Phys. Rev. Lett. 100, 090402 (2008)], and the density fluctuation data reported by Armijo et al. [Phys. Rev. Lett. 105, 230402 (2010)]. To facilitate such agreement, we propose and implement a quasi-one-dimensional stochastic equation for the low-energy, axial modes, while atoms in excited transverse modes are treated as independent ideal Bose gases.Comment: 10 pages, 5 figures; updated figures with experimental dat

Phase coherence in quasicondensate experiments: an ab initio analysis via the stochastic Gross-Pitaevskii equation

We perform an ab initio analysis of the temperature dependence of the phase coherence length of finite temperature, quasi-one-dimensional Bose gases measured in the experiments of Richard et al. (Phys. Rev. Lett. 91, 010405 (2003)) and Hugbart et al. (Eur. Phys. J. D 35, 155-163 (2005)), finding very good agreement across the entire observed temperature range ($0.8<T/T_{\phi}<28$). Our analysis is based on the one-dimensional stochastic Gross-Pitaevskii equation, modified to self-consistently account for transverse, quasi-one-dimensional effects, thus making it a valid model in the regime $\mu ~ few \hbar \omega_\perp$. We also numerically implement an alternative identification of $T_{\phi}$, based on direct analysis of the distribution of phases in a stochastic treatment.Comment: Amended manuscript with improved agreement to experiment, following some additional clarifications by Mathilde Hugbart and Fabrice Gerbier and useful comments by the reviewer; accepted for publication in Physical Review

Urinary estrogen metabolites and prostate cancer : a case-control study and meta-analysis

Objective: To investigate prostate cancer (Pca) risk in relation to estrogen metabolism, expressed as urinary 2-hydroxyestrone (2-OHE1), 16α-hydroxyestrone (16α-OHE1) and 2-OHE1 to 16α-OHE1 ratio. Methods: We conducted a case-control study within the Western New York Health Cohort Study (WNYHCS) from 1996 to 2001. From January 2003 through September 2004, we completed the re-call and follow-up of 1092 cohort participants. Cases (n = 26) and controls (n = 110) were matched on age, race and recruitment period according to a 1:4 ratio. We used the unconditional logistic regression to compute crude and adjusted odds ratios (OR) and 95% confident interval (CI) of Pca in relation to 2-OHE1, 16αOHE1 and 2-OHE1 to 16α-OHE1 by tertiles of urine concentrations (stored in a biorepository for an average of 4 years). We identified age, race, education and body mass index as covariates. We also conducted a systematic review of the literature which revealed no additional studies, but we pooled the results from this study with those from a previously conducted case-control study using the DerSimonian-Laird random effects method. Results: We observed a non-significant risk reduction in the highest tertile of 2-OHE1 (OR 0.72, 95% CI 0.25-2.10). Conversely, the odds in the highest tertile of 16α-OHE1 showed a non-significant risk increase (OR 1.76 95% CI 0.62-4.98). There was a suggestion of reduced Pca risk for men in the highest tertile of 2-OHE1 to 16α-OHE1 ratio (OR 0.56, 95% CI 0.19-1.68). The pooled estimates confirmed the association between an increased Pca risk and higher urinary levels of 16α-OHE1 (third vs. first tertile: OR 1.82, 95% CI 1.09-3.05) and the protective effect of a higher 2-OHE 1 to 16α-OHE1 ratio (third vs. first tertile: OR 0.53, 95% CI 0.31-0.90). Conclusion: Our study and the pooled results provide evidence for a differential role of the estrogen hydroxylation pathway in Pca development and encourage further study

The electromagnetic calorimeter of the AMS-02 experiment

The electromagnetic calorimeter (ECAL) of the AMS-02 experiment is a 3-dimensional sampling calorimeter, made of lead and scintillating fibers. The detector allows for a high granularity, with 18 samplings in the longitudinal direction, and 72 sampling in the lateral direction. The ECAL primary goal is to measure the energy of cosmic rays up to few TeV, however, thanks to the fine grained structure, it can also provide the separation of positrons from protons, in the GeV to TeV region. A direct measurement of high energy photons with accurate energy and direction determination can also be provided.Comment: Proceedings of SF2A conference 201

Genetic homogeneity in the deep-sea grenadier Macrourus berglax across the North Atlantic Ocean

Paucity of data on population structure and connectivity in deep sea species remains a major obstacle to their sustainable management and conservation in the face of ever increasing fisheries pressure and other forms of impacts on deep sea ecosystems. The roughhead grenadier Macrourus berglax presents all the classical characteristics of a deep sea species, such as slow growth and low fecundity, which make them particularly vulnerable to anthropogenic impact, due to their low resilience to change. In this study, the population structure of the roughhead grenadier is investigated throughout its geographic distribution using two sets of molecular markers: a partial sequence of the Control Region of mitochondrial DNA and species-specific microsatellites. No evidence of significant structure was found throughout the North Atlantic, with both sets of molecular markers yielding the same results of overall homogeneity. We posit two non-mutually exclusive scenarios that can explain such outcome: i) substantial high gene flow among locations, possibly maintained by larval stages, ii) very large effective size of post-glacially expanded populations. The results can inform management strategies in this by-caught species, and contribute to the broader issue of biological connectivity in the deep ocean

Direct route from ethanol to pure hydrogen through autothermal reforming in a membrane reactor: Experimental demonstration, reactor modelling and design

This work reports the integration of thin (∼3–4 μm thick) Pd-based membranes for H2 separation in a fluidized bed catalytic reactor for ethanol auto-thermal reforming. The performance of a fluidized bed membrane reactor has been investigated from an experimental and numerical point of view. The demonstration of the technology has been carried out over 50 h under reactive conditions using 5 thin Pd-based alumina-supported membranes and a 3 wt%Pt-10 wt%Ni catalyst deposited on a mixed CeO2/SiO2 support. The results have confirmed the feasibility of the concept, in particular the capacity to reach a hydrogen recovery factor up to 70%, while the operation at different fluidization regimes, oxygen-to-ethanol and steam-to-ethanol ratios, feed pressures and reactor temperatures have been studied. The most critical part of the system is the sealing of the membranes, where most of the gas leakage was detected. A fluidized bed membrane reactor model for ethanol reforming has been developed and validated with the obtained experimental results. The model has been subsequently used to design a small reactor unit for domestic use, showing that 0.45 m2 membrane area is needed to produce the amount of H2 required for a 5 kWe PEM fuel-cell based micro-CHP system.The presented work is funded within the FluidCELL project as part of the European Union's Seventh Framework Programme (FP7/ 2007-2013) for the Fuel Cells and Hydrogen Joint Technology Initiative under grant agreement nº 621196

The personal norm of reciprocity

Reciprocity is here considered as an internalized social norm, and a questionnaire to measure individual differences in the internalized norm of reciprocity is presented. The questionnaire, Personal Norm of Reciprocity (PNR), measures three aspects of reciprocity: positive reciprocity, negative reciprocity, and beliefs in reciprocity. The PNR has been developed and tested in two cultures, British and Italian, for a total of 951 participants. A cross-cultural study provides evidence of good psychometric properties and generalizability of the PNR. Data provide evidence for criterion validity and show that positive and negative reciprocators behave in different ways as a function of the valence (positive or negative) of the other's past behaviour, the type of feasible reaction (reward versus punishment), and the fairness of their reaction. Copyright (C) 2002 John Wiley Sons, Ltd

Chronic treatment with statins increases the availability of selenium in the antioxidant defence systems of hemodialysis patients.

Project. Oxidative stress (OS) is enhanced in hemodialysis (HD) patients. Lipid peroxidation and oxidative damage to glycids, proteins and nucleic acids are main consequences of OS and are associated to increased cardiovascular risk. Vitamin E and Glutathione Peroxidase (GSH-Px) represent main antioxidant systems in human cells. Selenium (Se), bound to the active sites of GSH-Px, plays a critical role in this antioxidant defense system. Statins are widely used and extensively investigated in the prevention of cardiovascular disease, notably in high-risk subjects. Several studies suggest that statins show antioxidant effects, protecting low-density lipoproteins from oxidation. Aim of our study was to compare serum Se concentration in ESRD patients on maintenance HD and in homogeneous healthy subjects and to investigate whether chronic assumption of statins may interfere with serum Se concentration in HD patients. Procedure. A total of 103 HD patients and 69 healthy subjects were enrolled; HD patients were then divided into patients who were not treated with statins (group A) and patients who assumed statins since six months at least (group B). Serum Se was determined by atomic absorption spectrometry. Results. Serum Se was significantly lower in HD patients of group A compared to healthy subjects (81.65±19.66mcg/L Vs. 96.47±15.62mcg/L, p<0.0040). However, in HD patients who assumed statins serum Se was significantly higher than in HD patients who did not. (111.83±18.82mcg/L Vs. 81.65±19.66mcg/L, p<0.0001). Conclusions. our results suggest that in HD patients chronic assumption of statins is related to a higher availability of active antioxidant agents and to reduced oxidative stress

Development of a High Temperature CO2 Sorbent Based on Hydrotalcite for a H2-Rich Syngas Production

To adapt hydrotalcite-based sorbents (also known as layered double hydroxides—LDHs) to high-temperature CO2 sorption compatible with tar steam reforming, the addition of CaO was investigated, maintaining the LHDs porosity and accessibility but mostly assuring the CO2 sorption stability during sorption/desorption cycles. In co-precipitation synthesis, the investigated parameters are (i) various interlayer anions with different sizes and valences (carbonate, oxalate, and stearate); (ii) various pH values; (iii) different Mg/Ca molar ratios. The characterization of these modified LDHs by TGA, XRD, N2 adsorption, SEM, sorption capacity, and sorption/desorption stability (cyclic TGA) allowed understanding the effect of the various synthesis parameters and highlighted the effect of oxalate use as the interlayer anion. After calcination of sorbent with Mg/Ca/Al ratio = 1/2/1, typical LDH sand roses were formed both with carbonate and oxalate anions: this former exhibited the highest sorption capacity and accessibility of CaO sites at 600&nbsp;°C, higher than pure CaO. However, the best stability during cycles was obtained with the sorbent from oxalate and Mg/Ca/Al ratio = 1.5/1.5/1 at pH 10 for which comparable sorption results are reached. For these two samples, the observed macro-porosity was associated with the highest specific surface area and pore volume. Graphic Abstract: [Figure not available: see fulltext.]