15,800 research outputs found

    Influence of statistical fluctuations on K/Ï€K/\pi ratios in relativistic heavy ion collisions

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    The influence of pure statistical fluctuations on K/Ï€K/\pi ratio is investigated in an event-by-event way. Poisson and the modified negative binomial distributions are used as the multiplicity distributions since they both have statistical background. It is shown that the distributions of the ratio in these cases are Gaussian, and the mean and relative variance are given analytically.Comment: 6 pages in RevTeX, 3 eps figures include

    Ground State Structure and Low Temperature Behaviour of an Integrable Chain with Alternating Spins

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    In this paper we continue the investigation of an anisotropic integrable spin chain, consisting of spins s=1s=1 and s=12s=\frac{1}{2}, started in our paper \cite{meissner}. The thermodynamic Bethe ansatz is analysed especially for the case, when the signs of the two couplings cˉ\bar{c} and c~\tilde{c} differ. For the conformally invariant model (cˉ=c~\bar{c}=\tilde{c}) we have calculated heat capacity and magnetic susceptibility at low temperature. In the isotropic limit our analysis is carried out further and susceptibilities are calculated near phase transition lines (at T=0T=0).Comment: 22 pages, LaTeX, uses ioplppt.sty and PicTeX macro

    Hard-Loop Effective Action for Anisotropic Plasmas

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    We generalize the hard-thermal-loop effective action of the equilibrium quark-gluon plasma to a non-equilibrium system which is space-time homogeneous but for which the parton momentum distribution is anisotropic. We show that the manifestly gauge-invariant Braaten-Pisarski form of the effective action can be straightforwardly generalized and we verify that it then generates all n-point functions following from collisionless gauge-covariant transport theory for a homogeneous anisotropic plasma. On the other hand, the Taylor-Wong form of the hard-thermal-loop effective action has a more complicated generalization to the anisotropic case. Already in the simplest case of anisotropic distribution functions, it involves an additional term that is gauge invariant by itself, but nontrivial also in the static limit.Comment: 12 pages. Version 3: typo in (15) corrected, note added discussing metric conventions use

    Discussion: behaviour of jacked and driven piles in sandy soil

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    Behaviour of jacked and driven piles in sandy soil

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    As an alternative to conventional dynamic pile installation methods, pile jacking is an environmentally friendly technique that could become more widely accepted. Great concern has arisen over the performance of jacked piles as compared with that of driven piles. This paper describes a comprehensive field study that was aimed at investigating the differences and similarities between the behaviour of jacked H-piles and that of driven H-piles. The instrumented piles, varying in length from 32 to 55 m and having a design capacity of up to 3540 kN, were installed in residual soils whose properties are close to silty sands. The load test results indicate that the shaft resistance of jacked piles is generally suffer and stronger than that of driven piles, but the base resistance of jacked piles is weaker than that of driven piles. At a load level of twice the design capacity, the percentage of pile head load carried by base varies from 2% to 10% for jacked piles, with a mean value of 6%; for driven piles the percentage varies from 6% to 61% with a mean value of 38%. The back-calculated values of the shaft friction coefficient, β, were found to be in a range of 0.25-0.6 for both jacked and driven piles. A correlation was also observed between the ultimate shaft friction and the mean standard penetration test N value (N̄), which suggests that the shaft friction can be taken as 1.5N̄ to 2N̄ (kPa) for both jacked and driven H-piles.published_or_final_versio

    Development of a SMA-fishing-line-McKibben bending actuator

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    High power-to-weight ratio soft artificial muscles are of overarching importance to enable inherently safer solutions to human-robot interactions. Traditional air driven soft McKibben artificial muscles are linear actuators. It is impossible for them to realize bending motions through a single McKibben muscle. Over two McKibben muscles should normally be used to achieve bending or rotational motions, leading to heavier and larger systems. In addition, air driven McKibben muscles are highly nonlinear in nature, making them difficult to be controlled precisely. A SMA(shape memory alloy)–fishing–line–McKibben (SFLM) bending actuator has been developed. This novel artificial actuator, made of a SMA-fishing-line muscle and a McKibben muscle, was able to produce the maximum output force of 3.0 N and the maximum bending angle (the rotation of the end face) of 61°. This may promote the application of individual McKibben muscles or SMA-fishing-line muscles alone. An output force control method for SFLM is proposed, and based on MATLAB/Simulink software the experiment platform is set up, the effectiveness of control system is verified through output force experiments. A three-fingered SFLM gripper driven by three SFLMs has been designed for a case study, which the maximum carrying capacity is 650.4 ± 0.2 g

    The 2016 Planned Giving Study

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    Charitable bequests and other planned gifts have historically played a significant role in the funding of higher education institutions. Prominent institutions such as Harvard University, Johns Hopkins University, and the Julliard School have been established as a direct result of bequests, and these gifts continue to have a profound impact today. The field of planned giving has become more sophisticated over time. However, the complexity of various planned giving vehicles and the comparatively long time period required for planned gifts to be formalized make it difficult for researchers to systematically track and examine planned giving behavior. Existing studies, therefore, heavily rely on self-reported survey data or tax returns. This study is one of the first efforts that seek to understand the changing landscape of planned giving and to explore donor life-cycle trajectories at higher education institutions. This whitepaper is the first in what is hoped to be a series of reports based upon data on planned gifts and donors in the field of higher education. The whitepaper discusses findings from five case-study universities located across the U.S. As the study expands the sample to include more universities and colleges in the next phase, this report series will offer richer data and insights into more underexplored, yet important, questions in planned giving

    A small synthetic molecule functions as a chloride–bicarbonate dual-transporter and induces chloride secretion in cells

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    A C2 symmetric small molecule composed of L-phenylalanine and isophthalamide was found to function as a Cl−/HCO3− dual transporter and self-assemble into chloride channels. In Ussing-chamber based short-circuit current measurements, this molecule elicited chloride-dependent short-circuit current (Isc) increase in both Calu-3 cell and CFBE41o-cell (with F508del mutant CFTR) monolayers.postprin
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