Nonlinear screening and percolative transition in a two-dimensional electron liquid

A novel variational method is proposed for calculating the percolation threshold, the real-space structure, and the thermodynamical compressibility of a disordered two-dimensional electron liquid. Its high accuracy is verified against prior numerical results and newly derived exact asymptotics. The inverse compressibility is shown to have a strongly asymmetric minimum at a density that is approximately the triple of the percolation threshold. This implies that the experimentally observed metal-insulator transition takes place well before the percolation point is reached.Comment: 4 pages, 2 figures. (v2) minor changes (v3) reference added (v4) few more references adde

Improving Underrepresented Minority Student Persistence in STEM.

Members of the Joint Working Group on Improving Underrepresented Minorities (URMs) Persistence in Science, Technology, Engineering, and Mathematics (STEM)-convened by the National Institute of General Medical Sciences and the Howard Hughes Medical Institute-review current data and propose deliberation about why the academic "pathways" leak more for URM than white or Asian STEM students. They suggest expanding to include a stronger focus on the institutional barriers that need to be removed and the types of interventions that "lift" students' interests, commitment, and ability to persist in STEM fields. Using Kurt Lewin's planned approach to change, the committee describes five recommendations to increase URM persistence in STEM at the undergraduate level. These recommendations capitalize on known successes, recognize the need for accountability, and are framed to facilitate greater progress in the future. The impact of these recommendations rests upon enacting the first recommendation: to track successes and failures at the institutional level and collect data that help explain the existing trends

Accounting for ecosystem services – Lessons from Australia for its application and use in Oceania to achieve sustainable development

This paper aims to illustrate the conceptual and practical issues that need to be considered if ecosystem service accounting is to be used to achieve sustainable development in Oceania. Recent international activity has focused on setting international standards for accounting for ecosystem services via the System of Environmental-Economic Accounting (SEEA). This includes defining the assets from which ecosystem services are generated. We examine how ecosystem services are incorporated into accounting and the benefits of doing this. This is done using Australia examples from the Great Barrier Reef region and elsewhere. Key lessons relate to: (1) the practical issues facing the producers of ecosystem accounts, including data availability and quality; (2) the need to account for both ecosystem services and ecosystem assets to assess sustainability, and; (3) explaining how ecosystem accounting can assist with sustainable development via policy as well as the management of specific ecosystem assets.Fujitsu Laboratories, Japan; Australian Government National Environmental Science Program Threatened Species Recovery Hu

High-harmonic generation from a confined atom

The order of high harmonics emitted by an atom in an intense laser field is limited by the so-called cutoff frequency. Solving the time-dependent Schr\"odinger equation, we show that this frequency can be increased considerably by a parabolic confining potential, if the confinement parameters are suitably chosen. Furthermore, due to confinement, the radiation intensity remains high throughout the extended emission range. All features observed can be explained with classical arguments.Comment: 4 pages(tex files), 4 figures(eps files); added references and comment

Generating equations using meta-analyses to predict iodine value of pork carcass back, belly, and jowl fat

Meta-analyses used data from existing literature to generate equations to predict finishing pig back, belly, and jowl fat iodine value (IV) followed by a prospective study to validate these equations. The final database included 24, 21, and 29 papers for back, belly, and jowl fat IV, respectively. For experiments that changed dietary fatty acid composition, initial diets (INT) were defined as those fed before the change in diet composition and final diets (FIN) were those fed after. The predictor variables tested were divided into 5 groups: (1) diet fat composition (dietary % C16:1, C18:1, C18:2, C18:3, essential fatty acid [EFA], UFA, and iodine value product) for both INT and FIN diets; (2) duration of feeding the INT and FIN diets; (3) ME or NE of the INT and FIN diet; (4) performance criteria (initial BW, final BW, ADG, ADFI, and G:F); and (5) carcass criteria (HCW and backfat thickness). PROC MIXED in SAS (SAS Institute, Inc., Cary, NC) was used to develop regression equations. Evaluation of models with significant terms was then conducted based on the Bayesian Information Criterion (BIC). The optimum equations to predict back, belly, and jowl fat IV were: backfat IV =84.83 + (6.87*INT EFA) - (3.90*FIN EFA) - (0.12*INT d) - (1.30*FIN d) - (0.11*INT EFA*FIN d) + (0.048*FIN EFA*INT d) + (0.12*FIN EFA*FIN d) - (0.0132*FIN NE) + (0.0011*FIN NE*FIN d) - (6.604*BF); belly fat IV = 106.16 + (6.21*INT EFA) - (1.50*FIN d) - (0.11*INT EFA*FIN d) - (0.0265*INT NE) + (0.00152*INT NE*FIN d) - (0.0816*HCW) - (6.35*BF); and jowl fat IV = 85.50 + (1.08*INT EFA) + (0.87*FIN EFA) - (0.014*INT d) - (0.050*FIN d) + (0.038*INT EFA*INT d) + (0.054*FIN EFA*FIN d) - (0.0146*INT NE) + (0.0322*INT BW) - (0.993*ADFI) - (7.366*BF), where INT EFA = initial period dietary essential fatty acids, %; FIN EFA = final period dietary essential fatty acids, %; INT d = initial period days; FIN d=final period days; INT NE = initial period dietary net energy, kcal/lb; FIN NE = final period dietary net energy, kcal/lb; BF = backfat depth, in.; ADFI = average daily feed intake, lb; INT BW = BW at the beginning of the experiment, lb. Dietary treatments from the validation experiment (see “Influence of Dietary Fat Source and Feeding Duration on Pig Growth Performance, Carcass Composition, and Fat Quality,†p. 210) consisted of a corn-soybean meal control diet with no added fat or a 3 × 3 factorial arrangement with main effects of fat source (4% tallow, 4% soybean oil, or a blend of 2% tallow and 2% soybean oil) and feeding duration (d 0 to 42, 42 to 84, or 0 to 84). The back, belly, and jowl fat IV equations tended to overestimate IV when actual IV values were less than approximately 65 g/100 g and underestimate belly fat IV when actual IV values were greater than approximately 74 g/100 g or when the blend or soybean oil diets were fed from d 42 to 84. Overall, with the exceptions noted, the regression equations were an accurate tool for predicting carcass fat quality based on dietary and pig performance factors.; Swine Day, Manhattan, KS, November 20, 201

Extracting structural features of rat sciatic nerve using polarization-sensitive spectral domain optical coherence tomography

We present spectral domain polarization-sensitive optical coherence tomography (SD PS-OCT) imaging of peripheral nerves. Structural and polarization-sensitive OCT imaging of uninjured rat sciatic nerves was evaluated both qualitatively and quantitatively. OCT and its functional extension, PS-OCT, were used to image sciatic nerve structure with clear delineation of the nerve boundaries to muscle and adipose tissues. A long-known optical effect, bands of Fontana, was also observed. Postprocessing analysis of these images provided significant quantitative information, such as epineurium thickness, estimates of extinction coefficient and birefringence of nerve and muscle tissue, frequency of bands of Fontana at different stretch levels of nerve, and change in average birefringence of nerve under stretched condition. We demonstrate that PS-OCT combined with regular-intensity OCT (compared with OCT alone) allows for a clearer determination of the inner and outer boundaries of the epineurium and distinction of nerve and muscle based on their birefringence pattern. PS-OCT measurements on normal nerves show that the technique is promising for studies on peripheral nerve injury. © 2012 Society of Photo-Optical Instrumentation Engineers (SPIE)

Influence of dietary fat source and feeding duration on finishing pig growth performance, carcass composition, and fat quality

Citation: Stephenson, E. W., Vaughn, M. A., Burnett, D. D., Paulk, C. B., Tokach, M. D., Dritz, S. S., . . . Gonzalez, J. M. (2016). Influence of dietary fat source and feeding duration on finishing pig growth performance, carcass composition, and fat quality. Journal of Animal Science, 94(7), 2851-2866. doi:10.2527/jas2015-9521A total of 160 finishing pigs (PIC 327 × 1050; initially 45.6 kg) were used in an 84-d experiment to evaluate the effects of dietary fat source and feeding duration on growth performance, carcass characteristics, and carcass fat quality. There were 2 pigs per pen with 8 pens per treatment. The 10 dietary treatments were a corn–soybean meal control diet with no added fat and a 3 × 3 factorial with main effects of fat source (4% tallow, 4% soybean oil, or a blend of 2% tallow and 2% soybean oil) and feeding duration (d 0 to 42, 42 to 84, or 0 to 84). The control corn– soybean meal diet was fed in place of added fat diets when needed for duration treatment purposes. On d 0, 1 pig was identified in each pen and fat biopsy samples of the back, belly, and jowl were collected on d 0, 41, and 81 for fatty acid analysis. At the conclusion of the study, all pigs were harvested, carcass characteristics were determined, and back, belly, and jowl fat samples were collected for analysis. Overall (d 0 to 84), there were no differences among pigs fed the different fat sources for growth and carcass characteristics; however, pigs fed diets with added fat for the entire study had improved (P = 0.036) G:F compared with pigs fed the control diet without added fat. Pigs fed supplemental fat throughout the entire study also had improved (P < 0.05) ADG and G:F as well as heavier d-84 BW (P = 0.006) compared with pigs fed additional fat during only 1 period. Adding fat for the entire study increased (P = 0.032) backfat and tended to reduce (P = 0.079) the fat free lean index compared with pigs fed the control diet without added fat. Added fat also increased (P < 0.05) the iodine value (IV) when compared with pigs fed the control diet. Increasing the feeding duration of soybean oil lowered MUFA and increased PUFA concentrations for all fat depots, whereas these values remained relatively unchanged by the addition of tallow (duration × fat source interactions, P < 0.05). Our study failed to show any feeding period × fat source interactions (P < 0.05) in fatty acid composition or IV for jowl fat, whereas this interaction occurred for belly fat and backfat, which would indicate a longer turnover rate for jowl fat. In conclusion, feeding additional fat improved ADG and G:F; however, feeding soybean oil for an increased duration, either alone or in combination with tallow, negatively affected the fatty acid composition and IV of different fat depots. © 2016 American Society of Animal Science. All rights reserved

Normal and abnormal NHC coordination in cationic hydride iodide complexes of aluminium

We thank the University of St Andrews and the EPSRC UK National Mass Spectrometry Facility (NMSF) at Swansea University.The mixed N-heterocyclic carbene (NHC) complexes NHCAlHxI3-x, where NHC is IDip or IMes ((HCNAr)2C:, Ar = 2,6-iPr2C6H3 = Dip (IDip); or 2,4,6-Me3C6H2 = Mes (IMes)), x = 1 or 2, were either prepared from NHCAlH3 and NHCAlI3 or by halogenation of NHCAlH3 with MeI. Reaction of [(IDip)AlHxI3-x], with x = 0-3, with another equivalent of a IDip afforded either fluxional equilibria in benzene solution for x = 0, no reaction for x = 3, or the new mixed normal-abnormal NHC-coordinated ionic complexes [(IDip)AlH2(aIDip)]I ( 9 ) and [(IDip)AlHI(aIDip)]I ( 10 ), where aIDip is the abnormal IDip carbene tautomer bonded through its 4-position. The molecular structures of 9 and 10 were determined and show slightly shorter Al–C(aIDip) than Al–C(IDip) distances. In addition, a complex containing [(IDip)AlI2(aIDip)]I ( 11 ) was structurally characterized though could not intentionally be synthesised. Possible formation mechanisms for 9 - 11 are discussed and the normal and abnormal IDip coordination to the aluminium(III) centre is believed to occur for steric reasons.PostprintPeer reviewe

Ambient particulate matter air pollution exposure and mortality in the NIH-AARP diet and health cohort

BACKGROUND: Outdoor fine particulate matter (≤ 2.5 μm; PM2.5) has been identified as a global health threat, but the number of large U.S. prospective cohort studies with individual participant data remains limited, especially at lower recent exposures. OBJECTIVES: We aimed to test the relationship between long-term exposure PM2.5 and death risk from all nonaccidental causes, cardiovascular (CVD), and respiratory diseases in 517,041 men and women enrolled in the National Institutes of Health-AARP cohort. METHODS: Individual participant data were linked with residence PM2.5 exposure estimates across the continental United States for a 2000–2009 follow-up period when matching census tract–level PM2.5 exposure data were available. Participants enrolled ranged from 50 to 71 years of age, residing in six U.S. states and two cities. Cox proportional hazard models yielded hazard ratio (HR) estimates per 10 μg/m3 of PM2.5 exposure. RESULTS: PM2.5 exposure was significantly associated with total mortality (HR = 1.03; 95% CI: 1.00, 1.05) and CVD mortality (HR = 1.10; 95% CI: 1.05, 1.15), but the association with respiratory mortality was not statistically significant (HR = 1.05; 95% CI: 0.98, 1.13). A significant association was found with respiratory mortality only among never smokers (HR = 1.27; 95% CI: 1.03, 1.56). Associations with 10-μg/m3 PM2.5 exposures in yearly participant residential annual mean, or in metropolitan area-wide mean, were consistent with baseline exposure model results. Associations with PM2.5 were similar when adjusted for ozone exposures. Analyses of California residents alone also yielded statistically significant PM2.5 mortality HRs for total and CVD mortality. CONCLUSIONS: Long-term exposure to PM2.5 air pollution was associated with an increased risk of total and CVD mortality, providing an independent test of the PM2.5–mortality relationship in a new large U.S. prospective cohort experiencing lower post-2000 PM2.5 exposure levels. CITATION: Thurston GD, Ahn J, Cromar KR, Shao Y, Reynolds HR, Jerrett M, Lim CC, Shanley R, Park Y, Hayes RB. 2016. Ambient particulate matter air pollution exposure and mortality in the NIH-AARP Diet and Health cohort. Environ Health Perspect 124:484–490; http://dx.doi.org/10.1289/ehp.150967

Identifying the drivers and constraints to adoption of IPM amongst arable farmers in UK and Ireland.

Publication history: Accepted - 2 May 2021; Published online - 15 May 2021.BACKGROUND Arable crops in temperate climatic regions such as the UK and Ireland are subject to a multitude of pests (weeds, diseases and vertebrate/invertebrate pests) that can negatively impact productivity if not properly managed. Integrated pest management (IPM) is widely promoted as a sustainable approach to pest management, yet there are few recent studies assessing adoption levels and factors influencing this in arable cropping systems in the UK and Ireland. This study used an extensive farmer survey to address both these issues. RESULTS Adoption levels of various IPM practices varied across the sample depending on a range of factors relating to both farm and farmer characteristics. Positive relationships were observed between IPM adoption and farmed area, and familiarity with IPM. Choice of pest control information sources was also found to be influential on farmer familiarity with IPM, with those who were proactive in seeking information from impartial sources being more engaged and reporting higher levels of adoption. CONCLUSION Policies that encourage farmers to greater levels of engagement with their pest management issues and more proactive information seeking, such as through advisory professionals, more experienced peers through crop walks, open days and discussion groups should be strongly encouraged.We acknowledge the financial and logistical support of the: Scottish Government Strategic Research Programme; Rural Business Research (England); Department of Agriculture, Food and the Marine (Ireland) (RSF 14/S/879); and the Department of Agriculture, Environment and Rural Affairs (Northern Ireland) in enabling the study reported here