On Tail Index Estimation based on Multivariate Data

This article is devoted to the study of tail index estimation based on i.i.d. multivariate observations, drawn from a standard heavy-tailed distribution, i.e. of which 1-d Pareto-like marginals share the same tail index. A multivariate Central Limit Theorem for a random vector, whose components correspond to (possibly dependent) Hill estimators of the common shape index alpha, is established under mild conditions. Motivated by the statistical analysis of extremal spatial data in particular, we introduce the concept of (standard) heavy-tailed random field of tail index alpha and show how this limit result can be used in order to build an estimator of alpha with small asymptotic mean squared error, through a proper convex linear combination of the coordinates. Beyond asymptotic results, simulation experiments illustrating the relevance of the approach promoted are also presented

Clinical assessment of the infant and child following perinatal brachial plexus injury.

STUDY DESIGN: Literature review. INTRODUCTION: After perinatal brachial plexus injury (PBPI), clinicians play an important role in injury classification as well as the assessment of recovery and secondary conditions. Early assessment guides the initial plan of care and influences follow-up and long-term outcome. PURPOSE: To review methods used to assess, classify and monitor the extent and influence of PBPI with an emphasis on guidelines for clinicians. METHODS: We use The International Classification of Functioning, Disability, and Health (ICF) model to provide a guide to assessment after PBPI for rehabilitation clinicians. DISCUSSION: With information gained from targeted assessments, clinicians can design interventions to increase the opportunities infants and children have for optimal recovery and to attain skills that allow participation in areas of interest

Sloshing in the LNG shipping industry: risk modelling through multivariate heavy-tail analysis

In the liquefied natural gas (LNG) shipping industry, the phenomenon of sloshing can lead to the occurrence of very high pressures in the tanks of the vessel. The issue of modelling or estimating the probability of the simultaneous occurrence of such extremal pressures is now crucial from the risk assessment point of view. In this paper, heavy-tail modelling, widely used as a conservative approach to risk assessment and corresponding to a worst-case risk analysis, is applied to the study of sloshing. Multivariate heavy-tailed distributions are considered, with Sloshing pressures investigated by means of small-scale replica tanks instrumented with d >1 sensors. When attempting to fit such nonparametric statistical models, one naturally faces computational issues inherent in the phenomenon of dimensionality. The primary purpose of this article is to overcome this barrier by introducing a novel methodology. For d-dimensional heavy-tailed distributions, the structure of extremal dependence is entirely characterised by the angular measure, a positive measure on the intersection of a sphere with the positive orthant in Rd. As d increases, the mutual extremal dependence between variables becomes difficult to assess. Based on a spectral clustering approach, we show here how a low dimensional approximation to the angular measure may be found. The nonparametric method proposed for model sloshing has been successfully applied to pressure data. The parsimonious representation thus obtained proves to be very convenient for the simulation of multivariate heavy-tailed distributions, allowing for the implementation of Monte-Carlo simulation schemes in estimating the probability of failure. Besides confirming its performance on artificial data, the methodology has been implemented on a real data set specifically collected for risk assessment of sloshing in the LNG shipping industry

Reducing the Dangers of Future Dangerousness Testimony: Applying the Federal Rules of Evidence to Capital Sentencing

The United States Supreme Court has long held that the death penalty cannot be imposed arbitrarily, and that during sentencing in capital cases, jurors must be provided with guidelines to assist them in narrowing down the class of individuals for whom the death penalty is appropriate. Typically, this is accomplished through the presentation of aggravating and mitigating evidence. One aggravating factor is a capital offender’s future dangerousness, or the likelihood that the individual will engage in violent institutional misconduct while in prison. Future dangerousness may be assessed using a variety of measures; Hare’s Psychopathy Checklist-Revised (PCL-R), a measure of personality traits associated with psychopathy, is one such measure that informs future dangerousness testimony. However, research suggests that the predictive validity of the PCL-R regarding violent institutional misconduct is weak-to-moderate, and that presentation of such evidence can prejudice jurors such that they will be more likely to assign the death penalty than they would in the absence of such evidence. These findings are concerning, particularly considering the severe social costs and individual rights deprivations associated with the death penalty. This Article will trace the history of Supreme Court capital sentencing decisions, examine the scientific literature regarding the predictive validity and bias potential for PCL-R evidence in capital sentencing, and argue that, in light of this weak literature base and the deleterious impact that misguided capital sentencing can have, applying the Federal Rules of Evidence to capital sentencing contexts may present an effective solution for keeping specious future dangerousness evidence out of the courtroom

Ultrashort pulse laser cutting of glass by controlled fracture propagation

International audienceLaser induced controlled fracture propagation has great potential in cutting brittle materials such as glass or sapphire. In this paper we demonstrate that the use of ultrashort pulse laser sources may be advantageous since it allows to overcome several restrictions of the convenient method

Surgical options for localized and advanced gastrointestinal stromal tumors

The development of imitinab has led to a revolution in the management of gastrointestinal stromal tumors (GIST), but surgical resection remains the cornerstone of treatment for patients with localized disease. The principles to surgical treatment of GIST include careful handling of tissues to prevent tumor rupture and resection to negative margins without the need for wide excision. Minimally invasive techniques have proven equally efficacious provided appropriate oncologic resections are performed. J. Surg. Oncol. 2011; 104:882–887. © 2011 Wiley Periodicals, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/88036/1/21892_ftp.pd

Seat of Choice: The Advantages of Flexible Seating

The focus of this Capstone Project is the advantages of Flexible Seating. This is important because students thrive off of choice in the classroom and Flexible Seating offers many ways for a student’s success. It is argued that teachers should implement Flexible Seating because of the increase in collaboration, student engagement, and overall success. The primary stakeholder perspective chosen was a veteran teacher who has implemented Flexible Seating and their fifth grade class, this is because of their experiences with this classroom design. Three themes emerged from an analysis of the data and were explored as ways to address the issue presented. Based on an analysis of the interviews and the relevant research literature, the researcher used what they learned to formulate an action that responded in a way that inspires, informs, or involves a particular audience

Advanced or metastatic gastrointestinal stromal tumors: Systemic treatment options

Gastrointestinal stromal tumor (GIST), the most common sarcoma arising in the gastrointestinal tract, typically expresses the tyrosine‐kinase receptor, C‐KIT, and contains activating mutation in the c‐kit or platelet‐derived growth factor receptor ( pdgfr ) gene. Recently, development of small molecules that inhibit the kinase activity of mutant C‐KIT and PDGFR proteins has radically changed treatment and prognosis of patients diagnosed with advanced GIST as this molecularly “targeted” therapy has demonstrated remarkable high‐level of activity in this disease. J. Surg. Oncol. 2011; 104:888–895. © 2011 Wiley Periodicals, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/88051/1/21930_ftp.pd