The Behavior of HEGY Tests for Quarterly Time Series with Seasonal Mean Shifts

This paper studies the behavior of the HEGY statistics for quarterly data, for seasonal autoregressive unit roots, when the analyzed time series is deterministic seasonal stationary but exhibits a change in the seasonal pattern. As a by-product we analyze also the HEGY test for the nonseasonal unit root, the data generation process being trend stationary too. Our results show that when the break magnitudes are finite the HEGY test statistics are not asymptotically biased towards the non-rejection of the seasonal and nonseasonal unit root hypotheses. However, the finite sample power properties may be substancially affected, the behavior of the tests depending on the type of the break. Hence, our results are also useful to understand and to predict this behavior under several circumstances.seasonality; unit roots; strctural breaks; HEGY tests

Kondo effect under the influence of spin–orbit coupling in a quantum wire

The analysis of the impact of spin–orbit coupling (SOC) on the Kondo state has generated considerable controversy, mainly regarding the dependence of the Kondo temperature T K on SOC strength. Here, we study the one-dimensional (1D) single impurity Anderson model (SIAM) subjected to Rashba (α) and Dresselhaus (β) SOC. It is shown that, due to time-reversal symmetry, the hybridization function between impurity and quantum wire is diagonal and spin independent (as it is the case for the zero-SOC SIAM), thus the finite-SOC SIAM has a Kondo ground state similar to that for the zero-SOC SIAM. This similarity allows the use of the Haldane expression for T K, with parameters renormalized by SOC, which are calculated through a physically motivated change of basis. Analytic results for the parameters of the SOC-renormalized Haldane expression are obtained, facilitating the analysis of the SOC effect over T K. It is found that SOC acting in the quantum wire exponentially decreases T K while SOC at the impurity exponentially increases it. These analytical results are fully supported by calculations using the numerical renormalization group (NRG), applied to the wide-band regime, and the projector operator approach, applied to the infinite-U regime. Literature results, using quantum Monte Carlo, for a system with Fermi energy near the bottom of the band, are qualitatively reproduced, using NRG. In addition, it is shown that the 1D SOC SIAM for arbitrary α and β displays a persistent spin helix SU(2) symmetry similar to the one for a 2D Fermi sea with the restriction α = β.VL acknowledges a PhD scholarship from the Brazilian Agency Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), process 160071/2015-1, and financial support from the Generalitat Valenciana through Grant reference Prometeo 2017/139. MM acknowledges a PhD scholarship from the Brazilian Agency Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES). GBM acknowledges financial support from CNPq, processes 424711/2018-4 and 305150/2017-0. EVA acknowledges financial support from CNPq, process 306000/2017-2

Hemorragia ocular intensa ocasionando cegueira em paciente com estigma falciforme que desenvolveu leptospirose. Relato de caso

This case report describes the findings of a 18 year-old black male from Bahia, a Northeastern state in Brazil, with the sickle cell trait, who developed bilateral hyphema and vitreous hemorrhage with blindness in the course of leptospirosis. The patient started to complain of blurred vision four days after the start of fever and muscular pain and approximately twelve hours after the introduction of penicillin. The severity of the leptospirosis in conjunction with sickle cell trait was considered to be the most likely explanation for this ocular complication.Este relato de caso descreve os achados em homem negro com 18 anos de idade, da Bahia, estado do nordeste do Brasil, com estigma falciforme que desenvolveu hifema bilateral e hemorragia vítrea com cegueira no curso de leptospirose. O paciente começou a se queixar de visão embaçada quatro dias após o início da febre e da dor muscular e aproximadamente 12 horas após o início da penicilina. A gravidade da leptospirose em conjunto com o estigma falciforme foi considerada a mais provável explicação para esta complicação ocular

Sleep in Infants with Congenital Heart Disease

OBJECTIVES: To investigate hypoxia and sleep disordered breathing in infants with congenital heart disease. METHODS: Prospective study. In-hospital full polysomnography was performed on 14 infants with congenital heart disease, age 7 ±1 months, and in 7 normal infants, age 10 ±2 months. Congenital heart disease infants were classified as acyanotic (n=7) or cyanotic (n=7). RESULTS: Nutritional status, assessed by the Gomez classification and expressed as % weight for age, was 70 ±7, 59 ±11 and 94 ±16 in the acyanotic, cyanotic congenital heart disease and control infants, respectively (p<0.001). The respiratory disturbance index (AHI, events per hour) was [median (25-75%)]: 2.5 (1.0-3.4), 2.4 (1.5-3.1) and 0.7 (0.7-0.9) in acyanotic, cyanotic CHD infants and controls, respectively (p=0.013). Almost all congenital heart disease infants (11 out of 14) and only one control infant had an AHI >1 event/hour. The minimum oxygen saturation was 79% (74-82), 73% (57-74) and 90% (90-91) in the acyanotic, cyanotic congenital heart disease infants and controls, respectively (p <0.001). The arousal index (events/hour) was similar among the three groups at 8.4 ±2.4, 10.3 ±8.7 and 6.5 ±3, respectively (p=0.451). CONCLUSIONS: Infants with congenital heart disease frequently present with sleep-disordered breathing associated with oxygen desaturations but not arousals. Therefore, sleep may represent a significant burden to infants with congenital heart disease

Finding Rare, Disease-Associated Variants in Isolated Groups: Potential Advantages of Mennonite Populations

Large-scale genotyping and next-generation sequencing techniques have allowed great advances in the field of molecular genetics. Numerous common variants of low impact have been associated with many complex human traits and diseases, such as bipolar disorder and schizophrenia. Although they may exert a greater impact on risk, few rare disease variants have been found, owing to the greatly increased sample sizes that are typically necessary to demonstrate association with rarer variants. One alternative strategy is to study isolated populations, where historical bottlenecks reduce genetic diversity and some otherwise rare variants may drift to higher frequencies. Here we describe the Mennonite population settlements, considering their history of multiple bottlenecks followed by demographic expansion and a currently widespread geographical distribution. We argue that Mennonite populations are valuable partners for studies seeking genetic variants that exert a high impact on risk for a variety of common disorders, including mental illnesses

Segmentação de pele e reconhecimento de gestos para interação humano-computador

This paper presents the development of a new approach to skin segmentation and hand gesture recognition in order to compose applications for Human Computer Interaction requiring real-time computing. Tests performed indicate the possibility of using the approach with low-cost equipment