Molecular dynamics simulation of the order-disorder phase transition in solid NaNO2_2

We present molecular dynamics simulations of solid NaNO$_2$ using pair potentials with the rigid-ion model. The crystal potential surface is calculated by using an \emph{a priori} method which integrates the \emph{ab initio} calculations with the Gordon-Kim electron gas theory. This approach is carefully examined by using different population analysis methods and comparing the intermolecular interactions resulting from this approach with those from the \emph{ab initio} Hartree-Fock calculations. Our numerics shows that the ferroelectric-paraelectric phase transition in solid NaNO$_2$ is triggered by rotation of the nitrite ions around the crystallographical c axis, in agreement with recent X-ray experiments [Gohda \textit{et al.}, Phys. Rev. B \textbf{63}, 14101 (2000)]. The crystal-field effects on the nitrite ion are also addressed. Remarkable internal charge-transfer effect is found.Comment: RevTeX 4.0, 11 figure

Experimental constraints on the astrophysical interpretation of the cosmic ray Galactic-extragalactic transition region

The energy region spanning from $\sim 10^{17}$ to $\lesssim 10^{19}$ eV is critical for understanding both, the Galactic and the extragalactic cosmic ray fluxes. This is the region where the propagation regime of nuclei inside the Galactic magnetic environment changes from diffusive to ballistic, as well as the region where, very likely, the most powerful Galactic accelerators reach their maximum output energies. In this work, a diffusion Galactic model is used to analyze the end of the Galactic cosmic ray spectrum and its mixing with the extragalactic cosmic ray flux. In particular, we study the conditions that must be met, from the spectral and composition points of view, by the Galactic and the extragalactic fluxes in order to reproduce simultaneously the total spectrum and elongation rate measured over the transition region by HiRes and Auger. Our analysis favors a mixed extragalactic spectrum in combination with a Galactic spectrum enhanced by additional high energy components, i.e., extending beyond the maximum energies expected from regular supernova remnants. The two additional components have mixed composition, with the lowest energy one heavier than the highest energy one. The potential impact on the astrophysical analysis of the assumed hadronic interaction model is also assessed in detail.Comment: 37 pages, 20 figure

Fruit and vegetable intake assessed by repeat 24 h recalls, but not by a dietary screener, is associated with skin carotenoid measurements in children

Accurate measurement of fruit and vegetable (FV) intake is important for nutrition surveillance and evaluation of dietary interventions. We compared two tools for reporting FV intake to objective measurement of skin carotenoids among children. FV cups/day was assessed by repeated 24 h dietary recalls (24H FV) and the National Cancer Institute’s All-Day Fruit and Vegetable Screener (NCI FV). Skin carotenoids were measured by repeated resonance Raman spectroscopy (RRS) of the palm. FV cups were regressed on RRS scores in unadjusted, field-based, and research-setting models with covariates feasible in each scenario. Data were baseline values from children aged 2–12 years in low-income households enrolled in a healthy eating randomized trial in four U.S. states (n = 177). Twenty-four-hour FV cups were associated with skin carotenoids in all models (p < 0.001) but NCI FV cups were not. Predicted RRS scores for discrete 24H FV cups provide a guide to interpretation of RRS in children (2 cups FV intake ~36,000 RRS units), with the research-setting scenario generally providing the narrowest prediction range (+/−1924). When self-reported data are required, 24 h recalls are more accurate than NCI FV screener data; and, when limited time, resources, or literacy must be considered, RRS scores can be quickly obtained and easily interpreted

Replacement of soya bean meal with peas and faba beans in growing/finishing pig diets: effect on performance, carcass composition and nutrient excretion

There is now an increasing debate about the viability of using temperate-grown legumes in pig diets as a potential replacement for imported soya bean meal (SBM) and this is due to food security, sustainability and environmental concerns. Two trials were designed to examine nitrogen (N) retention, growth performance and carcass quality of grower and finisher pigs when fed nutritionally balanced SBM-free diets formulated to contain peas or faba beans at 300 g/kg, compared to an SBM-containing, pulse-free control diet. Trial 1 evaluated N digestibility/retention in four iso-energetic diets, comparing the SBM control with one diet formulated with peas and two with faba bean cultivars; a tannin-containing and a tannin-free variety. This trial employed a four by four Latin Square design with four male pigs housed in metabolism crates, fed twice daily at 0.9 of assumed ad libitum intake over four time periods during grower (30–55 kg) and finisher (55–95 kg) phases. Quantitative faecal and urine collection allowed determination of N coefficient of total tract apparent digestibility, coefficient of apparent metabolisability, and N balance. Results revealed that dietary treatment did not affect these N parameters (P > 0.05) during either the grower or finisher phase. Trial 2 evaluated growth performance (feed intake, daily live weight gain and feed conversion ratio) and carcass quality parameters. Five diets (based on SBM, peas and one of three faba bean cultivars) balanced for standard ileal digestible amino acids and net energy were each fed to eight replicates of individually housed entire male pigs over the same growth phases as Trial 1. The inclusion of three faba bean varieties allowed comparison of animal responses between tannin/tannin-free and spring vs. winter bean cultivars. At ∼95 kg, pigs were slaughtered and a comprehensive range of carcass measurements undertaken. Samples of shoulder backfat were also taken at slaughter to determine skatole and indole concentrations. As with N balance, feeding treatment did not affect performance data. Carcass parameters revealed pigs fed with the pea-based diet had a greater dressing percentage than those animals on faba bean-based diets. Pigs fed with the SBM or pea-based diets also had greater lean meat percentages than those on faba-bean diets. Mean skatole concentrations for all pigs were below the accepted maximum threshold level of 0.2 μg/g. In conclusion, it is suggested that peas and faba beans can be successfully fed in balanced pig diets throughout the grower/finisher periods as alternatives to SBM

Community supported agriculture plus nutrition education improves skills, self-efficacy, and eating behaviors among low-income caregivers but not their children: a randomized controlled trial

Background: Adults and children in the U.S. consume inadequate quantities of fruit and vegetables (FV), in part, due to poor access among households with lower socioeconomic status. One approach to improving access to FV is community supported agriculture (CSA) in which households purchase a ‘share’ of local farm produce throughout the growing season. This study examined the effects of cost-offset (half-price) CSA plus tailored nutrition education for low-income households with children. Methods: The Farm Fresh Foods for Healthy Kids (F3HK) randomized controlled trial in New York, North Carolina, Vermont, and Washington (2016–2018) assigned caregiver-child dyads (n = 305) into cost-offset CSA plus education intervention or control (delayed intervention) groups. Following one growing season of CSA participation, changes in children’s diet quality, body mass index (BMI), and physical activity; caregivers’ nutrition knowledge, attitudes, behaviors, and diet quality; and household food access and security were examined using multiple linear or logistic regression, with adjustment for baseline value within an intent-to-treat (ITT) framework in which missing data were multiply imputed. Results: No significant net effects on children’s dietary intake, BMI, or physical activity were observed. Statistically significant net improvements were observed after one growing season for caregivers’ cooking attitudes, skills, and self-efficacy; FV intake and skin carotenoid levels; and household food security. Changes in attitudes and self-efficacy remained one-year after baseline, but improvements in caregiver diet and household food security did not. The number of weeks that participants picked up a CSA share (but not number of education sessions attended) was associated with improvements in caregiver FV intake and household food security. Conclusions: Cost-offset CSA plus tailored nutrition education for low-income households improved important caregiver and household outcomes within just one season of participation; most notably, both self-reported and objectively measured caregiver FV intake and household food security improved. Households that picked up more shares also reported larger improvements. However, these changes were not maintained after the CSA season ended. These results suggest that cost-offset CSA is a viable approach to improving adult, but not child, FV intake and household food security for low-income families, but the seasonality of most CSAs may limit their potential to improve year-round dietary behavior and food security. Trial registration: ClinicalTrials.gov. NCT02770196. Registered 5 April 2016. Retrospectively registered

Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS

We present the results of a search for new, heavy particles that decay at a significant distance from their production point into a final state containing charged hadrons in association with a high-momentum muon. The search is conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV and an integrated luminosity of 33 pb^-1 collected in 2010 by the ATLAS detector operating at the Large Hadron Collider. Production of such particles is expected in various scenarios of physics beyond the standard model. We observe no signal and place limits on the production cross-section of supersymmetric particles in an R-parity-violating scenario as a function of the neutralino lifetime. Limits are presented for different squark and neutralino masses, enabling extension of the limits to a variety of other models.Comment: 8 pages plus author list (20 pages total), 8 figures, 1 table, final version to appear in Physics Letters

Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio

Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS

The chi_b(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4 fb^-1, these states are reconstructed through their radiative decays to Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes. This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table, corrected author list, matches final version in Physical Review Letter

Measurement of the inclusive isolated prompt photon cross-section in pp collisions at sqrt(s)= 7 TeV using 35 pb-1 of ATLAS data

A measurement of the differential cross-section for the inclusive production of isolated prompt photons in pp collisions at a center-of-mass energy sqrt(s) = 7 TeV is presented. The measurement covers the pseudorapidity ranges |eta|<1.37 and 1.52<=|eta|<2.37 in the transverse energy range 45<=E_T<400GeV. The results are based on an integrated luminosity of 35 pb-1, collected with the ATLAS detector at the LHC. The yields of the signal photons are measured using a data-driven technique, based on the observed distribution of the hadronic energy in a narrow cone around the photon candidate and the photon selection criteria. The results are compared with next-to-leading order perturbative QCD calculations and found to be in good agreement over four orders of magnitude in cross-section.Comment: 7 pages plus author list (18 pages total), 2 figures, 4 tables, final version published in Physics Letters