4,750 research outputs found

    Clusters and Recurrence in the Two-Dimensional Zero-Temperature Stochastic Ising Model

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    We analyze clustering and (local) recurrence of a standard Markov process model of spatial domain coarsening. The continuous time process, whose state space consists of assignments of +1 or -1 to each site in Z2{\bf Z}^2, is the zero-temperature limit of the stochastic homogeneous Ising ferromagnet (with Glauber dynamics): the initial state is chosen uniformly at random and then each site, at rate one, polls its 4 neighbors and makes sure it agrees with the majority, or tosses a fair coin in case of a tie. Among the main results (almost sure, with respect to both the process and initial state) are: clusters (maximal domains of constant sign) are finite for times t<t< \infty, but the cluster of a fixed site diverges (in diameter) as tt \to \infty; each of the two constant states is (positive) recurrent. We also present other results and conjectures concerning positive and null recurrence and the role of absorbing states.Comment: 16 pages, 1 figur

    Data and performance of an active-set truncated Newton method with non-monotone line search for bound-constrained optimization

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    In this data article, we report data and experiments related to the research article entitled “A Two-Stage Active-Set Algorithm for Bound-Constrained Optimization”, by Cristofari et al. (2017). The method proposed in Cristofari et al. (2017), tackles optimization problems with bound constraints by properly combining an active-set estimate with a truncated Newton strategy. Here, we report the detailed numerical experience performed over a commonly used test set, namely CUTEst (Gould et al., 2015). First, the algorithm ASA-BCP proposed in Cristofari et al. (2017) is compared with the related method NMBC (De Santis et al., 2012). Then, a comparison with the renowned methods ALGENCAN (Birgin and Martínez et al., 2002) and LANCELOT B (Gould et al., 2003) is reported

    Developments in perfect simulation of Gibbs measures through a new result for the extinction of Galton-Watson-like processes

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    This paper deals with the problem of perfect sampling from a Gibbs measure with infinite range interactions. We present some sufficient conditions for the extinction of processes which are like supermartingales when large values are taken. This result has deep consequences on perfect simulation, showing that local modifications on the interactions of a model do not affect simulability. We also pose the question to optimize over a class of sequences of sets that influence the sufficient condition for the perfect simulation of the Gibbs measure. We completely solve this question both for the long range Ising models and for the spin models with finite range interactions.Comment: 28 page

    Influence of posture and coil position on the safety of a WPT system while recharging a compact EV

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    In this study, the human exposure to the magnetic field emitted by a wireless power transfer (WPT) system during the static recharging operations of a compact electric vehicle (EV) is evaluated. Specifically, the influence of the posture of realistic anatomical models, both in standing and lying positions, either inside or outside the EV, is considered. Aligned and misaligned coil configurations of the WPT system placed both in the rear and front position of the car floor are considered as well. Compliance with safety standards and guidelines has proven that reference levels are exceeded in the extreme case of a person lying on the floor with a hand close to the WPT coils, whereas the system is always compliant with the basic restrictions, at least for the considered scenarios

    Chassis influence on the exposure assessment of a compact ev during wpt recharging operations

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    In this study, the external magnetic field emitted by a wireless power transfer (WPT) system and the internal electric field induced in human body models during recharging operations of a compact electric vehicle (EV) are evaluated. The magneticfield is calculated with a hybrid scheme coupling the boundary element method with the surface impedance boundary conditions in order to fit the multiscale open-boundary characteristics of the problem. A commercial software is then used to perform numerical dosimetry. Specifically, two realistic anatomical models, both in a driving position and in a standing posture, are considered, and the chassis of the EV is modeled either as a currently employed aluminum alloy and as a futuristic carbon fiber composite panel. Aligned and misaligned coil configurations of the WPT system are considered as well. The analysis of the obtained results shows that the International Commission on Non-Ionizing Radiation Protection (ICNIRP) reference levels are exceeded in the driving position, especially for the carbon fiber chassis, whereas the system is compliant with the basic restrictions, at least for the considered scenarios

    Stochastic Precedence and Minima Among Dependent Variables

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    The notion of stochastic precedence between two random variables emerges as a relevant concept in several fields of applied probability. When one consider a vector of random variables X1,..,Xn, this notion has a preeminent role in the analysis of minima of the type minj∈AXj for A ⊂{1,…n}. In such an analysis, however, several apparently controversial aspects can arise (among which phenomena of “non-transitivity”). Here we concentrate attention on vectors of non-negative random variables with absolutely continuous joint distributions, in which a case the set of the multivariate conditional hazard rate (m.c.h.r.) functions can be employed as a convenient method to describe different aspects of stochastic dependence. In terms of the m.c.h.r. functions, we first obtain convenient formulas for the probability distributions of the variables minj∈AXj and for the probability of events {Xi=minj∈AXj}. Then we detail several aspects of the notion of stochastic precedence. On these bases, we explain some controversial behavior of such variables and give sufficient conditions under which paradoxical aspects can be excluded. On the purpose of stimulating active interest of readers, we present several comments and pertinent examples

    Evaluating the expression of urokinase and tissue leukocyte being in benign and malignant breast disease

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    Introduction: Our objectives is to show that the expression of uPA leukocyte could be considered, in the future, as a marker of the expression of uPA in the malignant tissue and therefore a potential indicator of prognosis. Methods: We examined the expression of uPa in leukocytes and tissues of three groups of women: with breast cancer; with benign breast lesion and healthy women (control group). We used RT Real Time PCR assay. The expression of urokinase is significantly higher in malignant breast lumps compared to benign lesions. However, in women with carcinoma of the breast, malignant tissue expresses higher amounts of uPA than the healthy counterpart. There are no statistically significant differences in the expression of uPA, between tissues taken from women with benign lesions. The lymphocytes taken from healthy volunteers show a level of expression of uPA significantly lower than the other tested samples Lymphocytes extracted from cancer patients express higher amounts of uPA compared to lymphocytes belonging to women with benign breast lesions. The expression of uPA was compared with the clinical and biological parameters commonly used in clinical practice for the definition of the prognosis. The only exception found, concerns those tumors characterized by the simultaneous negativity for estrogen receptors, progesterone and HER2 (state of triple negative), in which the expression of uPA is very high. Results and conclusions: Our data show that uPA expressed by leukocytes of each individual patient is the mirror image of the one expressed by malignant nodular uPA.Introduction: Our objectives is to show that the expression of uPA leukocyte could be considered, in the future, as a marker of the expression of uPA in the malignant tissue and therefore a potential indicator of prognosis. Methods: We examined the expression of uPa in leukocytes and tissues of three groups of women: with breast cancer; with benign breast lesion and healthy women (control group). We used RT Real Time PCR assay. The expression of urokinase is significantly higher in malignant breast lumps compared to benign lesions. However, in women with carcinoma of the breast, malignant tissue expresses higher amounts of uPA than the healthy counterpart. There are no statistically significant differences in the expression of uPA, between tissues taken from women with benign lesions. The lymphocytes taken from healthy volunteers show a level of expression of uPA significantly lower than the other tested samples Lymphocytes extracted from cancer patients express higher amounts of uPA compared to lymphocytes belonging to women with benign breast lesions. The expression of uPA was compared with the clinical and biological parameters commonly used in clinical practice for the definition of the prognosis. The only exception found, concerns those tumors characterized by the simultaneous negativity for estrogen receptors, progesterone and HER2 (state of triple negative), in which the expression of uPA is very high. Results and conclusions: Our data show that uPA expressed by leukocytes of each individual patient is the mirror image of the one expressed by malignant nodular uPA

    Which is the most accurate diagnostic procedure in Tamoxifen treated breast cancer patients

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    Purpose: The aim of this study was to evaluate the diagnostic accuracy of bi-dimensional (2D) and three-dimensional (3D) transvaginal ultrasound (TVUS), hysterosonography (HSSG) and hysteroscopy in the detection of endometrial pathology in women treated with tamoxifen (TMX) for breast cancer. Methods: Forty-two patients, affected by breast cancer under treatment with TMX, underwent 2D-3D TVUS, HSSG and hysteroscopy completed by biopsy, after abnormal findings following a routine 2D TVUS examination. Results: 3D-TVUS was more accurate than 2D-TVUS in the detection of atrophic endometrium confirmed by biopsy and in the detection of endometrial polyps. HSSG and hysteroscopy detected atrophic endometrium and endometrial polyps significantly better than ultrasound scan. Endometrial carcinoma was detected in two cases, and in both HSSG and hysteroscopy were 100% diagnostic. Conclusion: In TMX treated breast cancer patients, HSSG and hysteroscopy provide more accurate diagnosis than 2D-3D ultrasound in the detection of treatment related endometrial lesions

    APPROPRIATION ART E DIRITTO D&apos;AUTORE

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    Appropriation Art is generally defined as a form of contemporary art which borrows images from popular culture, advertising, the mass media, other artists and elsewhere, and incorporates them into new works of art. By taking these items out of their contexts and presenting them in new forms, combinations, or contexts, artists transform their meaning and force the viewer to reconsider his or her former understandings about a certain image. Appropriation art traces its origins back to Conceptual Art and, before, to the \u201creadymades\u201d of Marcel Duchamp, works (objet tout fait) consisting entirely of everyday objects presented largely unchanged as \u201cart.\u201d The originality and artistic value of these kinds of works lies in the new meaning associated with the work and in the artistic gesture, and not in its external aspect or form. Under a legal perpective, the main question arising out of Appropriation Art is whether the second work is a copy (thus, a counterfeit), a derivative work (requiring the copyright owner\u2019s consent to exploit the work of art) or, instead, a totally new and original work. To answer this question, this dissertation examines whether the appropriation artwork can be considered original under a copyright law standpoint, and analyzes the relationship between the appropriated work and the second work. Sometimes the works of Appropriation Art can be considered lawful as parody, insofar as they transform the meaning of a previous work for comic effect, creating a new artwork. This dissertation also analyzes the transformativeness relevant under the fair use analysis within US copyright system as well as the key fair use Appropriation Art cases handed down by US courts. In particular, the analysis focuses on the Jeff Koons and on the Mattel cases, and addresses the Cariou v. Prince case, relating to the alleged copy by renowned appropriation artist Richard Prince of Cariou\u2019s portraits of Jamaican Rastafarians for use in a series of paintings by Prince titled \u201cCanal Zone\u201d. In this case, the court held that the message behind the use of Cariou\u2019s photos in \u201cCanal Zone\u201d was so different from Cariou\u2019s message in the original portraits that Prince had transformed their meaning and therefore created new art. Italian courts addressed Appropriation Art only in one case, concerning the use by appropriation artist John Baldessari of certain works made by Alberto Giacometti. Finally, it is necessary to analyze Appropriation Art also under a trademark law standpoint, to assess whether appropriation of a mark can be considered trademark infringement
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