504 research outputs found

    A Third Report on the Experiments with Programs for the Simulation of Large Scale Automata on a Digital Computer

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    Control Systems Laboratory changed its name to Coordinated Science LaboratoryContract DA-36-039-SC-5669

    The significance of sample mass in the analysis of steroid estrogens in sewage sludges and the derivation of partition coefficients in wastewaters

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    Optimization of an analytical method for determination of steroid estrogens, through minimizing sample size, resulted in recoveries >84%, with relative standard deviations <3% and demonstrated the significance of sample size on method performance. Limits of detection were 2.1–5.3 ng/g. Primary sludges had estrogen concentrations of up to one order of magnitude less than those found in biological sludges (up to 994 ng/g). However, partition coefficients were higher in primary sludges (except estriol), with the most hydrophobic compound (ethinylestradiol) exhibiting the highest Kp value, information which may be of value to those involved in modeling removal during wastewater treatment

    Berry Curvature in Graphene: A New Approach

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    In the present paper we have directly computed the Berry curvature terms relevant for Graphene in the presence of an \textit{inhomogeneous} lattice distortion. We have employed the generalized Foldy Wouthuysen framework, developed by some of us \cite{ber0,ber1,ber2}. We show that a non-constant lattice distortion leads to a valley-orbit coupling which is responsible to a valley-Hall effect. This is similar to the valley-Hall effect induced by an electric field proposed in \cite{niu2} and is the analogue of the spin-Hall effect in semiconductors \cite{MURAKAMI, SINOVA}. Our general expressions for Berry curvature, for the special case of homogeneous distortion, reduce to the previously obtained results \cite{niu2}. We also discuss the Berry phase in the quantization of cyclotron motion.Comment: Slightly modified version, to appear in EPJ

    Determination of steroid estrogens in wastewater by high performance liquid chromatography-tandem mass spectrometry

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    This paper discusses the requirement for, and presents an analytical procedure for, the determination of four unconjugated steroid hormones and a conjugated steroid (estrone-3-sulfate) in wastewaters. The method quantifies the steroids by LC/MS/MS following solid phase extraction and a two stage clean-up procedure. Samples were extracted using C18 cartridges and eluates were then purified by gel permeation chromatography, followed by a further clean-up step on an aminopropyl cartridge. The limits of detection achieved were 0.2 ng l-1 for estriol, 17β-estradiol and 17α-ethinylestradiol, and 0.1 ng l-1 for estrone and the conjugate. The robustness of the method was demonstrated by achieving recoveries of >83% for all steroids in settled sewage and final effluent samples with relative standard deviations of 0.5 - 12%. The method was used to analyse a range of samples from a wastewater treatment works in south east England which demonstrated a >80% removal for estrone, estradiol and estriol with little impact on concentrations of ethinylestradiol or the conjugate

    Sociality predicts individual variation in the immunity of free-ranging rhesus macaques

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    This work was supported by CONICYT-Chilean scholarship [number 72190290], NIH grant [number R01AG060931] to N.S-M., L.J.N.B. and J.P.H., NIH grant [number R00AG051764] to N.S-M., NIH grant [number MH118203] to L.J.N.B.. and M.L.P, and NSF grant [number 1800558] to J.P.H. and Susan Anton. The CPRC is supported by the National Institutes of Health. An Animal and Biological Material Resource Center Grant [P40OD012217] was awarded to UPR from the Office of Research Infrastructure Programs (ORIP), and a Research Facilities Construction Grant [C06OD026690] was awarded for the renovation of CPRC facilities after Hurricane Maria.Social integration and social status can substantially affect an individual's health and survival. One route through which this occurs is by altering immune function, which can be highly sensitive to changes in the social environment. However, we currently have limited understanding of how sociality influences markers of immunity in naturalistic populations where social dynamics can be fully realized. To address this gap, we asked if social integration and social status in free-ranging rhesus macaques (Macaca mulatta) predict anatomical and physiological markers of immunity. We used data on agonistic interactions to determine social status, and social network analysis of grooming interactions to generate measures of individual variation in social integration. As measures of immunity, we included the size of two of the major organs involved in the immune response, the spleen and liver, and counts of three types of blood cells (red blood cells, platelets, and white blood cells). Controlling for body mass and age, we found that neither social status nor social integration predicted the size of anatomical markers of immunity. However, individuals that were more socially connected, i.e., with more grooming partners, had lower numbers of white blood cells than their socially isolated counterparts, indicating lower levels of inflammation with increasing levels of integration. These results build upon and extend our knowledge of the relationship between sociality and the immune system in humans and captive animals to free-ranging primates, demonstrating generalizability of the beneficial role of social integration on health.Publisher PDFPeer reviewe

    Trade-offs between sociality and gastrointestinal parasite infection in the context of a natural disaster

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    This work was supported by ANID-Chilean scholarship [number 72190290], the National Institutes of Health Grants [R01AG060931] to N.S-M., L.J.N.B. and J.P.H., [R00AG051764] to N.S-M, [R01MH118203] to M.L.P., M.J.M, L.J.N.B. and N.S-M., [R01MH096875] to M.L.P., L.J.N.B. and M.J.M., [U01MH121260] to N.S-M., M.L.P. and M.J.M., a European Research Council Consolidator Grant to L.J.N.B. [Friend Origins - 864461].Parasites and infectious diseases constitute important challenges particularly for group-living animals. Social contact and shared space can both increase parasite transmission risk, while individual differences in social capital can help prevent infections. For example, high social status individuals and those with more or stronger affiliative partnerships may have better immunity and, thus, lower parasitic burden. To test for health trade-offs in the costs and benefits of sociality, we quantified how parasitic load varied with an individual's social status, as well as with their affiliative relationships with weakly and strongly bonded partners, in a free-ranging population of rhesus macaques, Macaca mulatta. We found that high status was associated with a lower risk of protozoa infection at older ages compared to younger and low-status animals. Social resources can also be protective against infection under environmentally challenging situations, such as natural disasters. Using cross-sectional data, we additionally examined the impact of a major hurricane on the sociality - parasite relationship in this system and found that the hurricane influenced the prevalence of specific parasites independent of sociality. Overall, our study adds to the growing evidence for social status as a strong predictor of infection risk and highlights how extreme environmental events could shape vulnerability and resistance to infection.Peer reviewe

    Development of the Critical Thinking Toolkit (CriTT): a measure of student attitudes and beliefs about critical thinking

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    Critical thinking is an important focus in higher education and is essential for good academic achievement. We report the development of a tool to measure critical thinking for three purposes: (i) to evaluate student perceptions and attitudes about critical thinking, (ii) to identify students in need of support to develop their critical thinking, and (iii) to predict academic performance. Seventy-seven items were generated from focus groups, interviews and the critical thinking literature. Data were collected from 133 psychology students. Factor Analysis revealed three latent factors based on a reduced set of 27 items. These factors were characterised as: Confidence in Critical Thinking; Valuing Critical Thinking; and Misconceptions. Reliability analysis demonstrated that the sub-scales were reliable. Convergent validity with measures of grade point average and argumentation skill was shown, with significant correlations between subscales and validation measures. Most notably, in multiple regression analysis, the three sub-scales from the new questionnaire substantially increased the variance in grade point average accounted for by measures of reflective thinking and argumentation. To sum, the resultant scale offers a measure that is simple to administer, can be used as a diagnostic tool to identify students who need support in developing their critical thinking skills, and can also predict academic performance

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

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    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
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