Analyzing the relationship between air temperature and respiratory morbidity in children and the elderly in Porto Alegre, Brazil, before and during the COVID-19 pandemic.

The aim of the study was to analyze the relationship between air temperature data against hospital admissions due to respiratory diseases of children (under five years of age) and the elderly (over 65) in subtropical Porto Alegre, Brazil, comparing outcomes for 3 sequential years, 2018-2020, pre- and post-COVID 19 pandemic. Meteorological and hospital admission (HA) data for Porto Alegre, marked by a Koeppen-Geiger's Cfa climate type with well-defined seasons, were used in the analyses. HA was obtained for respiratory diseases (J00-99, according to the International Classification of Diseases, ICD-10) from the Brazilian DATASUS (Unified Health System database). We performed correlation analysis between variables (HA versus air temperature and heat stress) in order to identify existing relationships and lag effects (between meteorological condition and morbidity). Relative risk (RR) was also obtained for the two age groups during the three years. Results showed that the pandemic year disrupted observed patterns of association between analyzed variables, with either very low or non-existent correlations.

A probability model for the meiosis I non-disjunction fraction in numerical chromosomal anomalies.

Numerical chromosome abnormalities (aneuploidies) are among the most common known causes of mental retardation and the leading cause of pregnancy loss in humans. They primarily arise by the process of meiotic non-disjunction. We still know very little about the contribution of genetic and environmental causes for non-disjunction in humans. In order to increase our understanding of the epidemiology of human trisomies, it is necessary to establish the proportion of cases occurring in the first or second division of meiosis. Trisomic patients will display, in study of microsatellite typed by the polymerase chain reaction (PCR), three fragment peaks of equal intensity, two fragments at an average 2:1 dosage or one individual fragment. In this work we describe a statistical approach for estimation of the fraction of meiosis I non-disjunctions (F) in the absence of the parental information. First we determine a probability model for the number of peaks in a polymorphic microsatellite locus, which is a function of F. Based on this model, we obtain a maximum likelihood estimator for F, using the observed proportion of one, two and three allele patterns in trisomic individuals. Relying on the properties of maximum likelihood theory, we also calculate the asymptotic variance and confidence intervals for F. Owing to the fact that the samples of trisomic patients are limited in number, the use of asymptotic theory may be compromised. Thus, we employ the bootstrap technique to build confidence intervals for F and compare the results with those obtained from the normal theory. This estimator that dispenses the need to study parents opens the possibility of using archival material for comparative epidemiological studies of Down's syndrome and other aneuploidies. In this paper we propose a probability model to estimate the fraction of meiosis I non-disjunction, F, by only using the proportion of allele patterns of trisomy individuals, while traditional methods require typing pericentromeric markers from those affected and their parents.