Induced Ginibre ensemble of random matrices and quantum operations

A generalisation of the Ginibre ensemble of non-Hermitian random square matrices is introduced. The corresponding probability measure is induced by the ensemble of rectangular Gaussian matrices via a quadratisation procedure. We derive the joint probability density of eigenvalues for such induced Ginibre ensemble and study various spectral correlation functions for complex and real matrices, and analyse universal behaviour in the limit of large dimensions. In this limit the eigenvalues of the induced Ginibre ensemble cover uniformly a ring in the complex plane. The real induced Ginibre ensemble is shown to be useful to describe statistical properties of evolution operators associated with random quantum operations, for which the dimensions of the input state and the output state do differ.Comment: 2nd version, 34 pages, 5 figure

Estratégias de empresas para a base da pirâmide: estudo de casos múltiplos de grandes empresasnas comunidades pacificadas do Rio de Janeiro

A ausência do Estado nas comunidades de baixa renda do Rio de Janeiro afastou as empresas por décadas, visto que encontravam um ambiente hostil para desenvolver negócios. No entanto, recentemente, estas vêm passando por uma reorganização social e econômica apoiada na política pública de pacificação que visa reduzir a desordem social e atrair o interesse das empresas para as classes C, D e E, descritas na literatura por Prahalad (2004) como de base da pirÂmide (BOP). Neste artigo os autores contribuem para esta literatura ampliando e aprofundando o conhecimento sobre as estratégias de empresas para a BOP, tendo como objetivo analisar as estratégias que as grandes empresas vêm utilizando para atuar nestes mercados. O método de estudo de casos múltiplos foi utilizado com cinco grandes empresas: Light, L’Oréal, Banco do Brasil, Banco Santander e Sebrae, e a análise de conteúdo prescrita por Bardin (2008), com auxílio do software Atlas Ti 7.0, serviu para aprofundar a análise. Os resultados mostram que as empresas vêm disponibilizando novos produtos e serviços, orientação financeira, inclusão bancária, formalização do consumo e dos empreendedores locais, vem adaptando seus modelos de negócios e contribuindo para a integração destes territórios à sociedade formalmente estabelecida. No entanto, observa-se que as empresas que têm atuado de forma mais generosa tem alcançado melhores resultados e que as iniciativas se encontram em estágio inicial, carecendo de maior criatividade, coragem e independência das ações do Estado.The state absence in low-income communities in Rio de Janeiro drove away companies for decades, as they encountered a hostile environment for developing business. However, in recent years, the communities have been undergoing a social and economic reorganization supported by the pacification public policy that aims to reduce social disorder and attract private investment focused on classes C, D and E, described in the literature by Prahalad (2004) as the bottom of the pyramid. In this article, the authors contribute to this literature by broadening and deepening the knowledge about the companies’ strategies for the BOP, intending to analyze the strategies that large companies have been using to operate in these markets. The method was the multiple case studies covering five large companies: Light, L’Oréal, Banco do Brasil, Banco Santander and Sebrae, and the content analysis prescribed by Bardin (2008) guided the analysis using the software Atlas Ti 7.0. The results show that companies are offering new products and services, financial advice, banking services, access to microcredit, development and formalization of consumption and local entrepreneurs, and have been adapting their business models, contributing to the integration of these areas to the rest of the city formally established. However, it is observed that companies that have operated more generously have achieved better results and that initiatives are at an early stage of maturity, lacking more creativity, courage and independence of the state actions

PSAP-Expression in einem primären präsakralen neuroendokrinen Tumor: Verwechslungsmöglichkeit mit einem Prostatakarzinom

Zusammenfassung: Primäre präsakrale neuroendokrine Tumoren sind eine seltene Entität mit weniger als 30 beschriebenen Fällen in der Literatur. Wir berichten hier über einen autoptisch diagnostizierten präsakralen neuroendokrinen Tumor, der aufgrund seiner Lokalisation, Morphologie und immunhistochemischen Positivität für prostataspezifische saure Phosphatase (PSAP) zu Lebzeiten des Patienten als metastasiertes Prostatakarzinom fehldiagnostiziert wurde. Dies ist der erste Fallbericht, der eine Expression von PSAP und des Somatostatinrezeptors in dieser Entität dokumentiert

MRI biomarker assessment of neuromuscular disease progression: a prospective observational cohort study

BACKGROUND: A substantial impediment to progress in trials of new therapies in neuromuscular disorders is the absence of responsive outcome measures that correlate with patient functional deficits and are sensitive to early disease processes. Irrespective of the primary molecular defect, neuromuscular disorder pathological processes include disturbance of intramuscular water distribution followed by intramuscular fat accumulation, both quantifiable by MRI. In pathologically distinct neuromuscular disorders, we aimed to determine the comparative responsiveness of MRI outcome measures over 1 year, the validity of MRI outcome measures by cross-sectional correlation against functionally relevant clinical measures, and the sensitivity of specific MRI indices to early muscle water changes before intramuscular fat accumulation beyond the healthy control range. METHODS: We did a prospective observational cohort study of patients with either Charcot-Marie-Tooth disease 1A or inclusion body myositis who were attending the inherited neuropathy or muscle clinics at the Medical Research Council (MRC) Centre for Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, London, UK. Genetic confirmation of the chromosome 17p11·2 duplication was required for Charcot-Marie-Tooth disease 1A, and classification as pathologically or clinically definite by MRC criteria was required for inclusion body myositis. Exclusion criteria were concomitant diseases and safety-related MRI contraindications. Healthy age-matched and sex-matched controls were also recruited. Assessments were done at baseline and 1 year. The MRI outcomes-fat fraction, transverse relaxation time (T2), and magnetisation transfer ratio (MTR)-were analysed during the 12-month follow-up, by measuring correlation with functionally relevant clinical measures, and for T2 and MTR, sensitivity in muscles with fat fraction less than the 95th percentile of the control group. FINDINGS: Between Jan 19, 2010, and July 7, 2011, we recruited 20 patients with Charcot-Marie-Tooth disease 1A, 20 patients with inclusion body myositis, and 29 healthy controls (allocated to one or both of the 20-participant matched-control subgroups). Whole muscle fat fraction increased significantly during the 12-month follow-up at calf level (mean absolute change 1·2%, 95% CI 0·5-1·9, p=0·002) but not thigh level (0·2%, -0·2 to 0·6, p=0·38) in patients with Charcot-Marie-Tooth disease 1A, and at calf level (2·6%, 1·3-4·0, p=0·002) and thigh level (3·3%, 1·8-4·9, p=0·0007) in patients with inclusion body myositis. Fat fraction correlated with the lower limb components of the inclusion body myositis functional rating score (ρ=-0·64, p=0·002) and the Charcot-Marie-Tooth examination score (ρ=0·63, p=0·003). Longitudinal T2 and MTR changed consistently with fat fraction but more variably. In muscles with a fat fraction lower than the control group 95th percentile, T2 was increased in patients compared with controls (regression coefficients: inclusion body myositis thigh 4·0 ms [SE 0·5], calf 3·5 ms [0·6]; Charcot-Marie-Tooth 1A thigh 1·0 ms [0·3], calf 2·0 ms [0·3]) and MTR reduced compared with controls (inclusion body myositis thigh -1·5 percentage units [pu; 0·2], calf -1·1 pu [0·2]; Charcot-Marie-Tooth 1A thigh -0·3 pu [0·1], calf -0·7 pu [0·1]). INTERPRETATION: MRI outcome measures can monitor intramuscular fat accumulation with high responsiveness, show validity by correlation with conventional functional measures, and detect muscle water changes preceding marked intramuscular fat accumulation. Confirmation of our results in further cohorts with these and other muscle-wasting disorders would suggest that MRI biomarkers might prove valuable in experimental trials. FUNDING: Medical Research Council UK

Muscle MRI reveals distinct abnormalities in genetically proven non-dystrophic myotonias.

We assessed the presence, frequency and pattern of MRI abnormalities in non-dystrophic myotonia patients. We reviewed T1-weighted and STIR (short-tau-inversion-recovery) 3T MRI sequences of lower limb muscles at thigh and calf level in 21 patients with genetically confirmed non-dystrophic myotonia: 11 with CLCN1 mutations and 10 with SCN4A mutations, and 19 healthy volunteers. The MRI examinations of all patients showed hyperintensity within muscles on either T1-weighted or STIR images. Mild extensive or marked T1-weighted changes were noted in 10/21 patients and no volunteers. Muscles in the thigh were equally likely to be affected but in the calf there was sparing of tibialis posterior. Oedema was common in calf musculature especially in the medial gastrocnemius with STIR hyperintensity observed in 18/21 patients. In 10/11 CLCN1 patients this included a previously unreported "central stripe", also present in 3/10 SCN4A patients but no volunteers. Degree of fatty infiltration correlated with age (rho=0.46, p<0.05). Muscle MRI is frequently abnormal in non-dystrophic myotonia providing evidence of fatty infiltration and/or oedema. The pattern is distinct from other myotonic disorders; in particular the "central stripe" has not been reported in other conditions. Correlations with clinical parameters suggest a potential role for MRI as a biomarker

Universal microscopic correlation functions for products of independent Ginibre matrices

We consider the product of n complex non-Hermitian, independent random matrices, each of size NxN with independent identically distributed Gaussian entries (Ginibre matrices). The joint probability distribution of the complex eigenvalues of the product matrix is found to be given by a determinantal point process as in the case of a single Ginibre matrix, but with a more complicated weight given by a Meijer G-function depending on n. Using the method of orthogonal polynomials we compute all eigenvalue density correlation functions exactly for finite N and fixed n. They are given by the determinant of the corresponding kernel which we construct explicitly. In the large-N limit at fixed n we first determine the microscopic correlation functions in the bulk and at the edge of the spectrum. After unfolding they are identical to that of the Ginibre ensemble with n=1 and thus universal. In contrast the microscopic correlations we find at the origin differ for each n>1 and generalise the known Bessel-law in the complex plane for n=2 to a new hypergeometric kernel 0_F_n-1.Comment: 20 pages, v2 published version: typos corrected and references adde

The Influence of Board Structure and Ownership Concentration on GRI Reporting

Purpose – The purpose of this paper is to investigate the relationship between corporate governance structure and GRI reporting. More specifically, the study seeks to analyse board independence, board size and ownership concentration and their relationships with GRI reporting. Design/methodology/approach – The hypotheses of the study were tested in a sample of 287 Brazilian companies listed on the B3, the Brazilian stock exchange, using logistic regression models. Data from 2013 were collected from the Econoinfo and GRI databases. Findings –The findings show that there is a positive relationship between both board independence and GRI reporting and board size and GRI reporting, and a neutral relationship between ownership concentration and GRI reporting. These results indicate that the corporate governance structure influences a company’s decision to engage in social issue and stakeholders’ relationship activities. Originality/value – The contribution of this study is it presents theoretical arguments and empirical evidence regarding the influence of corporate governance structure on CSD beyond the Anglo-Saxon context. The results show that good corporate governance practices cannot be generalized to different contexts