1,367 research outputs found

    Topological Conformal Dimension

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    We investigate a quasisymmetrically invariant counterpart of the topological Hausdorff dimension of a metric space. This invariant, called the topological conformal dimension, gives a lower bound on the topological Hausdorff dimension of quasisymmetric images of the space. We obtain results concerning the behavior of this quantity under products and unions, and compute it for some classical fractals. The range of possible values of the topological conformal dimension is also considered, and we show that this quantity can be fractional.Comment: 16 pages, revised after referee's reports. To appear in Conformal Geometry and Dynamic

    Weak decay processes in pre-supernova core evolution within the gross theory

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    The beta decay and electron capture rates are of fundamental importance in the evolution of massive stars in a pre-supernova core. The beta decay process gives its contribution by emitting electrons in the plasma of the stellar core, thereby increasing pressure, which in turn increases the temperature. From the other side, the electron capture removes free electrons from the plasma of the star core contributing to the reduction of pressure and temperature. In this work we calculate the beta decay and electron capture rates in stellar conditions for 63 nuclei of relevance in the pre-supernova stage, employing Gross Theory as the nuclear model. We use the abundances calculated with the Saha equations in the hypothesis of nuclear statistical equilibrium to evaluate the time derivative of the fraction of electrons. Our results are compared with other evaluations available in the literature. They have shown to be one order less or equal than the calculated within other models. Our results indicate that these differences may influence the evolution of the star in the later stages of pre-supernova. © 2014. The American Astronomical Society. All rights reserved..Fil: Ferreira, R. C.. Universidade Estadual Do Sudoeste Da Bahía; BrasilFil: Dimarco, A. J.. Universidade Estadual de Santa Cruz, Bahía, Brasil; BrasilFil: Samana, Arturo Rodolfo. Universidade Estadual de Santa Cruz, Bahía, Brasil; BrasilFil: Barbero, César Alberto. Universidad Nacional de La Plata. Facultad de Ciencias Exactas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentin

    The effects of bedrest on crew performance during simulated shuttle reentry. Volume 2: Control task performance

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    A simplified space shuttle reentry simulation performed on the NASA Ames Research Center Centrifuge is described. Anticipating potentially deleterious effects of physiological deconditioning from orbital living (simulated here by 10 days of enforced bedrest) upon a shuttle pilot's ability to manually control his aircraft (should that be necessary in an emergency) a comprehensive battery of measurements was made roughly every 1/2 minute on eight military pilot subjects, over two 20-minute reentry Gz vs. time profiles, one peaking at 2 Gz and the other at 3 Gz. Alternate runs were made without and with g-suits to test the help or interference offered by such protective devices to manual control performance. A very demanding two-axis control task was employed, with a subcritical instability in the pitch axis to force a high attentional demand and a severe loss-of-control penalty. The results show that pilots experienced in high Gz flying can easily handle the shuttle manual control task during 2 Gz or 3 Gz reentry profiles, provided the degree of physiological deconditioning is no more than induced by these 10 days of enforced bedrest

    The Moment Guided Monte Carlo method for the Boltzmann equation

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    In this work we propose a generalization of the Moment Guided Monte Carlo method developed in [11]. This approach permits to reduce the variance of the particle methods through a matching with a set of suitable macroscopic moment equations. In order to guarantee that the moment equations provide the correct solutions, they are coupled to the kinetic equation through a non equilibrium term. Here, at the contrary to the previous work in which we considered the simplified BGK operator, we deal with the full Boltzmann operator. Moreover, we introduce an hybrid setting which permits to entirely remove the resolution of the kinetic equation in the limit of infinite number of collisions and to consider only the solution of the compressible Euler equation. This modification additionally reduce the statistical error with respect to our previous work and permits to perform simulations of non equilibrium gases using only a few number of particles. We show at the end of the paper several numerical tests which prove the efficiency and the low level of numerical noise of the method.Comment: arXiv admin note: text overlap with arXiv:0908.026

    Purification and Characterization of Acinetobacter calcoaceticus 4-Hydroxybenzoate 3-Hydroxylase after Its Overexpression in Escherichia coli

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    4-Hydroxybenzoate 3-hydroxylase [EC 1.14.13.2] from Acinetobacter calcoaceticus was purified to homogeneity following the 40-fold overexpression of this gene (pobA) in Escherichia coli. Overexpression was accomplished by placing the folA gene (encoding trimethoprim-resistant dihydrofolate reductase) directly downstream of the pobA gene, and demanding growth of recombinants on elevated concentration of trimethoprim. Presumably, the surviving variants have undergone a genetic alteration which allowed the overexpression of both folA and pobA. 4-Hydroxybenzoate 3-hydroxylase was purified in two chromatographic steps, characterized biochemically, and its properties were compared to those of its homolog from Pseudomonas fluorescens. The two enzymes differ in their reponse to Cl− ion inhibition. A single ami no acid change in the putative NADPH-binding site is proposed to account for this difference. The inhibitory and catalytic properties of substrate analogs were also examine

    PATHOLOGICAL GAMBLING: AN ASSOCIATION WITH ALEXITHYMIA, PERSONALITY DISORDERS AND CLINICAL SYNDROMES

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    Pathological gambling (PG) is a disorder recently conceptualized as a behavioural addiction, because of its neurobiological, neurophysiological and psychological features (American Psychiatric Association. Diagnostic and statistical manual of mental disorders - 5th ed., 2013; Potenza et al., 2012). PG represents both a social and a sanitary cost, in terms of pharmacological and psychological therapies. The aim of this study was to examine the correlation between personality disorders, clinical syndromes and alexithymia levels in a group of pathological gamblers. Furthermore this study aimed at highlighting a relationship between PG and alexithymia, over and above the relationship between personality disorders, clinical syndromes and PG. Sixty treatment- seeking pathological gamblers and 60 healthy controls were included in the study. Psychological assessment included the South Oaks Gambling Screen (SOGS), the Millon Clinical Multiaxial Inventory (MCMI-III) and the Toronto Alexithymia Scale (TAS-20). Pathological gamblers displayed Axis I disorders, such as anxiety, somatoform symptoms, bipolar symptoms, dysthymia, thought disorders and major depression, as well as Axis II disorders such as depressive, antisocial, sadistic, passive-aggressive, self-defeating and paranoid disorders, and greater alexithymia levels. Alexithymia was detected in PG independently from the presence of other psychiatric disorders. Our data show that comorbid psychiatric disorders have been evidentiated in PG. Interestingly alexithymia is related to PG indipendently from other psychopathological disorders, representing a relevant feature, helpful for assessing PG diagnosis and for orienting to the correct therapeutical strategy. REFERENCES American Psychiatric Association. 2013. American Psychiatric Publishing Potenza et al.,2012Psychoph219(2):469-49

    The Virtues of Abstention: Separation of Powers in Al-Nashiri II

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    (Excerpt) Part I examines various scholarly approaches to judicial deference, then considers deference in the context of military commissions. In Part II, the history of military commissions in the United States is examined, paying particular attention to the extended dialogue among the coordinate federal branches that created the system currently in operation. The decision in Al-Nashiri II not to adjudicate a collateral attack on one of these commissions is the focus of Part III. That Part embraces the underlying jurisdictional challenge at stake in Al-Nashiri II, the development of abstention doctrine generally and as applied to the current commissions, as well as the role judicial deference played in the panel’s decision. Finally, in Part IV, this Note argues that the path of abstention had many virtues in this case and as a rule of law, because it furthered sound separation of powers principles by respecting the considered judgments of Congress and successive Presidents. Part IV first categorizes the type of deference the panel engaged in by abstaining. Next, it considers the effect the decision will have on future collateral attacks on commission proceedings, as federal courts will now review military commission final judgments, just as Congress and the President intended, rather than intervening indiscriminately. This Note argues that this effect will, in turn, preserve the commission system created by Congress—the branch best suited to weigh the intricate national security considerations involved in prosecuting and bringing to justice those who, in their attempt to thwart our military effort, violate the laws of war

    Zygmund graphs are thin for doubling measures

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    The Zygmund functions form an intermediate class between Lipschitz and H\"older functions; their second order divided differences are uniformly bounded. It is well known that for d1d \geq 1 the graph of any Lipschitz function f:RdRf:\R^d \rightarrow \R is thin for doubling measures, and we extend this result to the Zygmund class
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