João Riboldi

Estudo da sobrevida de pacientes com câncer de mama atendidas no hospital da Universidade Federal de Santa Maria, Rio Grande do Sul, Brasil

This retrospective hospital-based study aimed to describe health conditions and to estimate the survival of 252 patients diagnosed with breast cancer and treated at the Mastology Outpatient Clinic at the University Hospital of the Federal University in Santa Maria, Rio Grande do Sul, Brazil, from 1980 to 2000. Analysis followed the Kaplan-Meier and Cox model. Mean age was 54, and 73.4% of the patients had a histological diagnosis of invasive ductal carcinoma, 63.9% showed no lymph node involvement, and 57.6% were clinical stage II. At the end of the study, 64.7% were alive and free of breast cancer and 5.1% had died of other causes. Five-year survival was 87.7% for all women, and prognostic factors associated with survival were tumor size (HR = 12.03; > 5cm), lymph node involvement (HR = 3.08; N1) and number (HR = 4.66; None), and estrogen (HR = 0.34) and c-erbB-2 (HR = 2.51) receptors. Based on the results, intensive awareness-raising campaigns are vitally important for implementing breast cancer screening to achieve early diagnosis.

Gonadal hormone regulation of glial fibrillary acidic protein immunoreactivity in the medial amygdala subnuclei across the estrous cycle and in castrated and treated female rats

The medial amygdala (MeA) is a sexually dimorphic area that modulates neuroendocrine and behavioral activities and where gonadal hormones play an important role in neuron-glial and synaptic plasticity. Immunohistochemistry was used to identify the astrocytic marker glial fibrillary acidic protein (GFAP) in the different MeA subnuclei--anterodorsal (MeAD), posterodorsal (MePD) and posteroventral (MePV)--of intact female rats in the different phases of the estrous cycle and in ovariectomized females treated with hormonal substitutive therapy. Data semi-quantified by optical densitometry showed that, in the proestrus phase, the GFAP immunoreactivity (GFAP-ir) was higher when compared to the other phases of the estrous cycle (P < 0.02). GFAP-ir was also higher in the MePD than in the MeAD or in the MePV (P < 0. 02). In ovariectomized females, injections of estradiol alone or estradiol plus progesterone increased GFAP-ir in the MePD and in the MePV (P < 0.001), but not in the MeAD (P > 0.3), when compared to control data. These findings suggest that astrocytic GFAP in the MeA subnuclei can be affected either by physiological levels or by hormonal manipulation of the ovarian steroids, which may contribute to the plasticity of local and integrated functional activities of these brain areas in female rats.

Determinantes contextuais da mortalidade neonatal no Rio Grande do Sul por dois modelos de análise

OBJETIVO: Analisar os determinantes da mortalidade neonatal, segundo modelo de regressao logistica multinivel e modelo hierarquico classico. METODOS: Estudo de coorte com 138.407 nascidos vivos com declaracao de nascimento e 1.134 obitos neonatais registrados em 2003 no estado do Rio Grande do Sul. Foram vinculados os registros do Sistema de Informacoes sobre Nascidos Vivos e Mortalidade para o levantamento das informacoes sobre exposicao no nivel individual. As variaveis independentes incluiram caracteristicas da crianca ao nascer, da gestacao, da assistencia a saude e fatores sociodemograficos. Fatores associados foram estimados e comparados por meio da analise de regressao logistica classica e multinivel. RESULTADOS: O coeficiente de mortalidade neonatal foi 8,19 por mil nascidos vivos. As variaveis que se mostraram associadas ao obito neonatal no modelo hierarquico foram: baixo peso ao nascer, Apgar no 1o e 5o minutos inferiores a oito, presenca de anomalia congenita, prematuridade e perda fetal anterior. Cesariana apresentou efeito protetor. No modelo multinivel, a perda fetal anterior nao se manteve significativa, mas a inclusao da variavel contextual (taxa de pobreza) indicou que 15% da variacao da mortalidade neonatal podem ser explicados pela variabilidade nas taxas de pobreza em cada microrregiao. CONCLUSOES: O uso de modelos multiniveis foi capaz de mostrar pequeno efeito dos determinantes contextuais na mortalidade neonatal. Foi observada associacao positiva com a taxa de pobreza, no modelo geral, e com o percentual de domicilios com abastecimento de agua entre os nascidos pre-termos.OBJECTIVE To analyze neonatal mortality determinants using multilevel logistic regression and classic hierarchical models. METHODS Cohort study including 138,407 live births with birth certificates and 1,134 neonatal deaths recorded in 2003, in the state of Rio Grande do Sul, Southern Brazil. The Information System on Live Births and mortality records were linked for gathering information on individual-level exposures. Sociodemographic data and information on the pregnancy, childbirth care and characteristics of the children at birth were collected. The associated factors were estimated and compared by traditional and multilevel logistic regression analysis. RESULTS The neonatal mortality rate was 8.19 deaths per 1,000 live births. Low birth weight, 1- and 5-minute Apgar score below eight, congenital malformation, pre-term birth and previous fetal loss were associated with neonatal death in the traditional model. Elective cesarean section had a protective effect. Previous fetal loss did not remain significant in the multilevel model, but the inclusion of a contextual variable (poverty rate) showed that 15% of neonatal mortality variation can be explained by varying poverty rates in the microregions. CONCLUSIONS The use of multilevel models showed a small effect of contextual determinants on the neonatal mortality rate. There was found a positive association with the poverty rate in the general model, and the proportion of households with water supply among preterm newborns.OBJETIVO: Analizar los determinantes de la mortalidad neonatal, segun modelo de regresion logistica multinivel y modelo jerarquico clasico. METODOS: Estudio de cohorte con 138.407 nacidos vivos con declaracion de nacimiento y 1.134 obitos neonatales registrados en 2003 en Rio Grande do Sul, Sur de Brasil. Se vincularon los registros del Sistema de Informaciones sobre Nacidos Vivos y Mortalidad para el levantamiento de las informaciones sobre exposicion en el nivel individual. Las variables independientes incluyeron caracteristicas del nino al nacer, de la gestacion y asistencia a la salud, y factores sociodemograficos. Factores asociados fueron estimados y comparados por medio del analisis de regresion logistica clasica y multinivel. RESULTADOS: El coeficiente de mortalidad neonatal fue 8,19 por mil nacidos vivos. Las variables que se mostraron asociadas al obito neonatal en el modelo jerarquico fueron: bajo peso al nacer, Apgar en el 1o y 5o minutos inferiores a ocho, presencia de anomalia congenita, prematuridad y perdida fetal anterior. La cesarea presento efecto protector. En el modelo multinivel, la perdida fetal anterior no se mantuvo significativa, pero la inclusion de la variable contextual (tasa de pobreza) indico que 15% de la variacion de la mortalidad neonatal pueden ser explicados por la variabilidad en las tasas de pobreza en cada microrregion. CONCLUSIONES: El uso de modelos multiniveles fue capaz de mostrar pequeno efecto de los determinantes contextuales en la mortalidad neonatal. Se observo asociacion positiva con la tasa de pobreza, en el modelo general, y con el porcentual de residencias con abastecimiento de agua, entre los prematuros.

Empirical models to predict soil nitrogen mineralization

Modelos empiricos sao equacoes matematicas que podem ser ajustadas a resultados experimentais. Esses modelos podem ser utilizados para avaliar ou predizer fenomenos observados ou dados experimentais e auxiliar no desenvolvimento de praticas adequadas de manejo do solo. Desse modo, o presente trabalho teve por objetivo comparar oito modelos matematicos descritos na literatura, utilizando como dados experimentais o N mineralizado de dez solos do Rio Grande do Sul, acumulado durante 32 semanas de incubacao. O N mineralizado foi obtido experimentalmente em um experimento de incubacao, seguido de lixiviacao com CaCl2 0,01mol L-1. O N mineral foi determinado no comeco do periodo de incubacao e ao final da 2a, 4a, 8a, 16a e 32a semanas. Entre os modelos testados, o melhor ajuste do N mineralizado foi obtido com os modelos exponenciais simples, ao passo que a obtencao desses ajustes nos modelos exponenciais duplos esteve condicionado ao aumento de parâmetros na equacao. Em funcao dos resultados observados e das condicoes experimentais, conclui-se que a hipotese em que os modelos exponenciais duplos estao baseados, isto e, na presenca de dois compartimentos de nitrogenio suscetiveis a mineralizacao, foi rejeitada.

Teoria da resposta ao item aplicada ao Inventário de Depressão Beck

The Beck Depression Inventory (BDI), a scale that measures the latent trait intensity of depression symptoms, can be assessed by the Item Response Theory (IRT). This study used the Graded-Response model (GRM) to assess the intensity of depressive symptoms in 4,025 individuals who responded to the BDI, in order to efficiently use the information available on different aspects enabled by the use of this methodology. The fit of this model was done in PARSCALE software. We identified 13 items of the BDI in which at least one response category was not more likely than others to be chosen, so that these items had to be categorized again. The items with greater power of discrimination were sadness, pessimism, feeling of failure, dissatisfaction, self-hatred, indecision, and difficulty of work. The most serious items were weight loss, suicidal ideas, and social withdrawal. The group of 202 individuals with the highest levels of depressive symptoms was comprised by 74% of women and almost 84% had a diagnosis of a psychiatric disorder. The results show gains resulting from use of IRT in the analysis of latent traits.

Contextual determinants of neonatal mortality using two analysis methods, Rio Grande do Sul, Brazil

OBJETIVO: Analisar os determinantes da mortalidade neonatal, segundo modelo de regressao logistica multinivel e modelo hierarquico classico. METODOS: Estudo de coorte com 138.407 nascidos vivos com declaracao de nascimento e 1.134 obitos neonatais registrados em 2003 no estado do Rio Grande do Sul. Foram vinculados os registros do Sistema de Informacoes sobre Nascidos Vivos e Mortalidade para o levantamento das informacoes sobre exposicao no nivel individual. As variaveis independentes incluiram caracteristicas da crianca ao nascer, da gestacao, da assistencia a saude e fatores sociodemograficos. Fatores associados foram estimados e comparados por meio da analise de regressao logistica classica e multinivel. RESULTADOS: O coeficiente de mortalidade neonatal foi 8,19 por mil nascidos vivos. As variaveis que se mostraram associadas ao obito neonatal no modelo hierarquico foram: baixo peso ao nascer, Apgar no 1o e 5o minutos inferiores a oito, presenca de anomalia congenita, prematuridade e perda fetal anterior. Cesariana apresentou efeito protetor. No modelo multinivel, a perda fetal anterior nao se manteve significativa, mas a inclusao da variavel contextual (taxa de pobreza) indicou que 15% da variacao da mortalidade neonatal podem ser explicados pela variabilidade nas taxas de pobreza em cada microrregiao. CONCLUSOES: O uso de modelos multiniveis foi capaz de mostrar pequeno efeito dos determinantes contextuais na mortalidade neonatal. Foi observada associacao positiva com a taxa de pobreza, no modelo geral, e com o percentual de domicilios com abastecimento de agua entre os nascidos pre-termos.OBJECTIVE To analyze neonatal mortality determinants using multilevel logistic regression and classic hierarchical models. METHODS Cohort study including 138,407 live births with birth certificates and 1,134 neonatal deaths recorded in 2003, in the state of Rio Grande do Sul, Southern Brazil. The Information System on Live Births and mortality records were linked for gathering information on individual-level exposures. Sociodemographic data and information on the pregnancy, childbirth care and characteristics of the children at birth were collected. The associated factors were estimated and compared by traditional and multilevel logistic regression analysis. RESULTS The neonatal mortality rate was 8.19 deaths per 1,000 live births. Low birth weight, 1- and 5-minute Apgar score below eight, congenital malformation, pre-term birth and previous fetal loss were associated with neonatal death in the traditional model. Elective cesarean section had a protective effect. Previous fetal loss did not remain significant in the multilevel model, but the inclusion of a contextual variable (poverty rate) showed that 15% of neonatal mortality variation can be explained by varying poverty rates in the microregions. CONCLUSIONS The use of multilevel models showed a small effect of contextual determinants on the neonatal mortality rate. There was found a positive association with the poverty rate in the general model, and the proportion of households with water supply among preterm newborns.OBJETIVO: Analizar los determinantes de la mortalidad neonatal, segun modelo de regresion logistica multinivel y modelo jerarquico clasico. METODOS: Estudio de cohorte con 138.407 nacidos vivos con declaracion de nacimiento y 1.134 obitos neonatales registrados en 2003 en Rio Grande do Sul, Sur de Brasil. Se vincularon los registros del Sistema de Informaciones sobre Nacidos Vivos y Mortalidad para el levantamiento de las informaciones sobre exposicion en el nivel individual. Las variables independientes incluyeron caracteristicas del nino al nacer, de la gestacion y asistencia a la salud, y factores sociodemograficos. Factores asociados fueron estimados y comparados por medio del analisis de regresion logistica clasica y multinivel. RESULTADOS: El coeficiente de mortalidad neonatal fue 8,19 por mil nacidos vivos. Las variables que se mostraron asociadas al obito neonatal en el modelo jerarquico fueron: bajo peso al nacer, Apgar en el 1o y 5o minutos inferiores a ocho, presencia de anomalia congenita, prematuridad y perdida fetal anterior. La cesarea presento efecto protector. En el modelo multinivel, la perdida fetal anterior no se mantuvo significativa, pero la inclusion de la variable contextual (tasa de pobreza) indico que 15% de la variacion de la mortalidad neonatal pueden ser explicados por la variabilidad en las tasas de pobreza en cada microrregion. CONCLUSIONES: El uso de modelos multiniveles fue capaz de mostrar pequeno efecto de los determinantes contextuales en la mortalidad neonatal. Se observo asociacion positiva con la tasa de pobreza, en el modelo general, y con el porcentual de residencias con abastecimiento de agua, entre los prematuros.

Risk factors for low birth weight in Rio Grande do Sul State, Brazil: classical and multilevel analysis

The objective of this study was to identify risk factors for low birth weight in singleton live born infants in Rio Grande do Sul State, Brazil, in 2003, based on data from the Information System on Live Births. The study used both classical multivariate and multilevel logistic regression. Risk factors were evaluated at two levels: individual (live births) and contextual (micro-regions). At the individual level the two models showed a significant association between low birth weight and prematurity, number of prenatal visits, congenital anomalies, place of delivery, parity, sex, maternal age, maternal occupation, marital status, schooling, and type of delivery. In the multilevel models, the greater the urbanization of the micro-region, the higher the risk of low birth weight, while in less urbanized micro-regions, single mothers had an increased risk of low birth considering all live births. Low birth weight varied according to micro-region and was associated with individual and contextual characteristics. Although most of the variation in low birth weight occurred at the individual level, the multilevel model identified an important risk factor in the contextual level.

Infant mortality trends in the State of Rio Grande do Sul, Brazil, 1994-2004: a multilevel analysis of individual and community risk factors

The aim of this study was to analyze the trend in infant mortality rates in the State of Rio Grande do Sul, Brazil, from 1994 to 2004, in a longitudinal ecological study, by means of panel data analysis and multilevel linear regression (two levels: microregion and time) to estimate factors associated with infant mortality. The infant mortality rate decreased from 19.2 per thousand (1994) to 13.7 per thousand (2004) live births, and the principal causes of death in the last five years were perinatal conditions (54.1%). Approximately 47% of the variation in mortality occurred in the microregions, and a 10% increase in coverage by the Family Health Program was associated with a 1 per thousand reduction in infant mortality. A 10% increase in the poverty rate was associated with a 2.1 per thousand increase in infant deaths. Infant mortality was positively associated with the proportion of low birthweight newborns and the number of hospital beds per thousand inhabitants and negatively associated with the cesarean rate and number of hospitals per 100 thousand inhabitants. The findings suggest that individual and community variables display significant effects on the reduction of infant mortality rates.O objetivo deste trabalho foi analisar a tendencia das taxas de mortalidade infantil no Rio Grande do Sul, Brasil, de 1994 a 2004, em estudo ecologico longitudinal, por meio de analise de dados de painel e regressao linear multinivel (dois niveis: microrregiao e tempo) para estimar fatores associados a mortalidade infantil. A taxa de mortalidade infantil reduziu de 19,2‰ (1994) para 13,7‰ (2004) nascidos vivos, e a principal causa de obito, nos ultimos cinco anos, foi afeccoes perinatais (54,1%). Aproximadamente 47% da variacao nas taxas de mortalidade ocorreram nas microrregioes, e 10% de acrescimo na cobertura do Programa Saude da Familia esteve associado a reducao de 1‰ na mortalidade infantil. O aumento de 10% na taxa de pobreza esteve associado com um aumento de 2,1‰ nos obitos infantis. A mortalidade infantil associou-se positivamente com a proporcao de recem-nascidos com baixo peso e numero de leitos hospitalares por mil habitantes e negativamente com a proporcao de cesarianas e numero de hospitais por 100 mil habitantes. Os resultados sugerem que variaveis individuais e contextuais apresentam efeitos significativos na reducao das taxas de mortalidade infantil.

Associação entre métodos de adaptabilidade e estabilidade em milho

Grain yield data were used from 65 maize cultivar trials carried out in the State of the Rio Grande do Sul, Brazil, in the years of 2002/2003, 2003/2004 and 2004/2005, with the objective of comparing the following methods of adaptability and stability analysis: Yates and Cochran, Plaisted and Peterson, Wricke, Annicchiarico, Finlay and Wilkinson, Eberhart and Russell, Tai, Toler, Silva and Barreto, Cruz et al., Huehn, Lin and Binns modified by Carneiro and analysis AMMI. To verify the degree of association between the estimates of adaptability and stability parameters, obtained by the different methods, the Spearman correlation coefficient was used. There is an agreement in the indication of maize cultivars by the methods of Plaisted and Peterson and Wricke, of Annicchiarico and Lin and Binns modified by Carneiro, of Eberhart and Russell and Tai, and of Toler and Silva and Barreto, which counter-indicates their concomitant use. To a lesser degree of association the AMMI analysis agrees with the estimates of the stability parameters, Plaisted and Peterson, Wricke, Eberhart and Russell, Tai, Silva and Barreto and Cruz et al.

Ajuste de modelo para quantificar o efeito de plantas daninhas e época de semeadura no rendimento de soja

Adjustment of model to quantify the effect of weeds and sowing time on soybean yield Abstract - The objective of this work was to adjust and validate a mathematical model based beggarticks (Bidens spp.) and arrowleaf sida (Sida rhombifolia L.) densities, integrating the soybean seeding time after plant cover desiccation as a variable in order to quantify the losses in grain yield. Four experiments were conducted in Passo Fundo and Eldorado do Sul, RS, Brazil. Treatments consisted of beggarticks and arrowleaf sida densities, and soybean seeding times in relation to plant cover desiccation date. In the trials performed with beggarticks, soybean seeding was carried 3, 7, and 11 days after desiccation (DAD) of plant cover, in both locations. In the trials that included arrow leaf sida, soybean seeding was performed 3, 7, and 11 DAD in Passo Fundo, and 20, 24, and 28 DAD in Eldorado do Sul. In order to analyse the data, it was used the rectangular hyperbolic model, which incorporates weed density and its emergence time in relation to the crop. Delaying soybean seeding in relation to plant cover desiccation increased the levels of crop grain yield losses due to weed interference, mainly for beggarticks. The rectangular hyperbolic model can be used to predict soybean grain yield losses for both weed species.