1,492 research outputs found

    Scaling in the Lattice Gas Model

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    A good quality scaling of the cluster size distributions is obtained for the Lattice Gas Model using the Fisher's ansatz for the scaling function. This scaling identifies a pseudo-critical line in the phase diagram of the model that spans the whole (subcritical to supercritical) density range. The independent cluster hypothesis of the Fisher approach is shown to describe correctly the thermodynamics of the lattice only far away from the critical point.Comment: 4 pages, 3 figure

    The Upper Extremity Functional Index (UEFI). Cross-cultural adaptation, reliability, and validity of the italian version

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    SUMMARY Introduction. The Italian version of the Upper Extremity Functional Index (UEFI) may help assess shoulder function in patients with shoulder problems, especially athletes. Objective. Translate and cross-culturally adapt UEFI into Italian; verify UEFI validity and reliability in professional and amateur athletes with upper limb musculoskeletal disorders, shoulder, in particular. Methods. This study was conducted with 150 participants with musculoskeletal disorders of the upper limb. UEFI, the short version of the Disability of the Arm, Shoulder and Hand scale (Quick DASH), the Shoulder Pain and Disability Index, and the Short Form-36 Health Survey (SF-36) were administered. Acceptability was assessed in terms of refusal rate, rates of missing responses, and administration time; test-retest reliability was assessed with intraclass correlation coefficient (ICC); internal consistency was assessed with Cronbach’s alpha coefficient, and validity was assessed by Pearson’s correlation coefficients. Results. Cronbach’s alpha coefficients for the UEFI on test and retest were α = 0.979 and α = 0.985, respectively. The average measure ICC was 0.917. The UEFI score demonstrated strong negative correlations with SPADI total score (-0.636), Quick DASH score (-0.685), and SF-36 score (-0.327). Conclusions. The Italian version of UEFI is acceptable, valid, and reliable

    Isotopic composition of fragments in multifragmentation of very large nuclear systems: effects of the chemical equilibrium

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    Studies on the isospin of fragments resulting from the disassembly of highly excited large thermal-like nuclear emitting sources, formed in the ^{197}Au + ^{197}Au reaction at 35 MeV/nucleon beam energy, are presented. Two different decay systems (the quasiprojectile formed in midperipheral reactions and the unique source coming from the incomplete fusion of projectile and target in the most central collisions) were considered; these emitting sources have the same initial N/Z ratio and excitation energy (E^* ~= 5--6 MeV/nucleon), but different size. Their charge yields and isotopic content of the fragments show different distributions. It is observed that the neutron content of intermediate mass fragments increases with the size of the source. These evidences are consistent with chemical equilibrium reached in the systems. This fact is confirmed by the analysis with the statistical multifragmentation model.Comment: 9 pages, 4 ps figure

    Goodness-of-fit tests of Gaussianity: constraints on the cumulants of the MAXIMA data

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    In this work, goodness-of-fit tests are adapted and applied to CMB maps to detect possible non-Gaussianity. We use Shapiro-Francia test and two Smooth goodness-of-fit tests: one developed by Rayner and Best and another one developed by Thomas and Pierce. The Smooth tests test small and smooth deviations of a prefixed probability function (in our case this is the univariate Gaussian). Also, the Rayner and Best test informs us of the kind of non-Gaussianity we have: excess of skewness, of kurtosis, and so on. These tests are optimal when the data are independent. We simulate and analyse non-Gaussian signals in order to study the power of these tests. These non-Gaussian simulations are constructed using the Edgeworth expansion, and assuming pixel-to-pixel independence. As an application, we test the Gaussianity of the MAXIMA data. Results indicate that the MAXIMA data are compatible with Gaussianity. Finally, the values of the skewness and kurtosis of MAXIMA data are constrained by |S| \le 0.035 and |K| \le 0.036 at the 99% confidence level.Comment: New Astronomy Reviews, in pres

    Effects of surface modifications on molecular diffusion in mesoporous catalytic materials

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    In this work, we use pulsed-field gradient (PFG) NMR to probe molecular diffusion of liquids inside mesoporous structures and assess the influence of surface modifications, namely, deposition of palladium (Pd) nanoparticles over alumina (Al2O3) surfaces and passivation of titania (TiO2) surfaces with alkyl chains, on the diffusion pattern

    Fixed-point elimination in the intuitionistic propositional calculus

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    It is a consequence of existing literature that least and greatest fixed-points of monotone polynomials on Heyting algebras-that is, the algebraic models of the Intuitionistic Propositional Calculus-always exist, even when these algebras are not complete as lattices. The reason is that these extremal fixed-points are definable by formulas of the IPC. Consequently, the Ό\mu-calculus based on intuitionistic logic is trivial, every Ό\mu-formula being equivalent to a fixed-point free formula. We give in this paper an axiomatization of least and greatest fixed-points of formulas, and an algorithm to compute a fixed-point free formula equivalent to a given Ό\mu-formula. The axiomatization of the greatest fixed-point is simple. The axiomatization of the least fixed-point is more complex, in particular every monotone formula converges to its least fixed-point by Kleene's iteration in a finite number of steps, but there is no uniform upper bound on the number of iterations. We extract, out of the algorithm, upper bounds for such n, depending on the size of the formula. For some formulas, we show that these upper bounds are polynomial and optimal

    Transient backbending behavior in the Ising model with fixed magnetization

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    The physical origin of the backbendings in the equations of state of finite but not necessarily small systems is studied in the Ising model with fixed magnetization (IMFM) by means of the topological properties of the observable distributions and the analysis of the largest cluster with increasing lattice size. Looking at the convexity anomalies of the IMFM thermodynamic potential, it is shown that the order of the transition at the thermodynamic limit can be recognized in finite systems independently of the lattice size. General statistical mechanics arguments and analytical calculations suggest that the backbending in the caloric curve is a transient behaviour which should not converge to a plateau in the thermodynamic limit, while the first order transition is signalled by a discontinuity in other observables.Comment: 24 pages, 11 figure

    Topology of event distribution as a generalized definition of phase transitions in finite systems

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    We propose a definition of phase transitions in finite systems based on topology anomalies of the event distribution in the space of observations. This generalizes all the definitions based on the curvature anomalies of thermodynamical potentials and provides a natural definition of order parameters. The proposed definition is directly operational from the experimental point of view. It allows to study phase transitions in Gibbs equilibria as well as in other ensembles such as the Tsallis ensemble.Comment: 4 pages, 3 figure

    Secondary consent to biospecimen use in a prostate cancer biorepository

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    BACKGROUND: Biorepository research has substantial societal benefits. This is one of the few studies to focus on male willingness to allow future research use of biospecimens. METHODS: This study analyzed the future research consent questions from a prostate cancer biorepository study (N = 1931). The consent form asked two questions regarding use of samples in future studies (1) without and (2) with protected health information (PHI). Yes to both questions of use of samples was categorized as Yes-Always; Yes to without and No to with PHI was categorized as Yes-Conditional; No to without PHI was categorized as Never. We analyzed this outcome to determine significant predictors for consent to Yes-Always vs. Yes-Conditional. RESULTS: 99.33 % consented to future use of samples; 88.19 % consented to future use without PHI, and among those men 10.2 % consented to future use with PHI. Comparing Yes Always and Yes Conditional responses, bivariate analyses showed that race, family history, stage of cancer, and grade of cancer (Gleason), were significant at the α = 0.05 level. Using stepwise multivariable logistic regression, we found that African–American men were significantly more likely to respond Yes Always when compared to White men (p < 0.001). Those with a family history of prostate cancer were significantly more likely to respond Yes Always (p = 0.002). CONCLUSIONS: There is general willingness to consent to future use of specimens without PHI among men
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