A Generalized Log-Normal Model for Grouped Survival Data

It is common to have experiments in which it is not possible to observe the exact lifetimes but only the interval where they occur. This sort of data presents a high number of ties and it is called grouped or interval-censored survival data. Regression methods for grouped data are available in the statistical literature. The regression structure considers modeling the probability of a subject's survival past a visit time conditional on his survival at the previous visit. Two approaches are presented: assuming that lifetimes come from (1) a continuous proportional hazards model and (2) a logistic model. However, there may be situations in which none of the models are adequate for a particular data set. This article proposes the generalized log-normal model as an alternative model for discrete survival data. This model was introduced by Chen (1995) and it is extended in this article for grouped survival data. A real example related to a Chagas disease illustrates the proposed model.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Comparison of Methods for the Identification of Coagulase-negative Staphylococci

Coagulase-negative staphylococci (CNS) species identification is still difficult for most clinical laboratories. The scheme proposed by Kloos and Schleifer and modified by Bannerman is the reference method used for the identification of staphylococcal species and subspecies; however, this method is relatively laborious for routine use since it requires the utilization of a large number of biochemical tests. The objective of the present study was to compare four methods, i.e., the reference method, the API Staph system (bioMérieux) and two methods modified from the reference method in our laboratory (simplified method and disk method), in the identification of 100 CNS strains. Compared to the reference method, the simplified method and disk method correctly identified 100 and 99% of the CNS species, respectively, while this rate was 84% for the API Staph system. Inaccurate identification by the API Staph method was observed for Staphylococcus epidermidis (2.2%), S. hominis (25%), S. haemolyticus (37.5%), and S. warneri (47.1%). The simplified method using the simple identification scheme proposed in the present study was found to be efficient for all strains tested, with 100% sensitivity and specificity and proved to be available alternative for the identification of staphylococci, offering, higher reliability and lower cost than the currently available commercial systems. This method would be very useful in clinical microbiology laboratory, especially in places with limited resources

Predictive factors of mortality in pediatric patients with acute renal injury associated with sepsis,

Abstract: Objective: To evaluate the prognosis factors of children with sepsis and acute kidney injury. Methods: This was a retrospective study of children with sepsis and acute kidney injury that were admitted to the pediatric intensive care unit (PICU) of a tertiary hospital. A multivariate analysis was performed to compare risk factors for mortality. Results: Seventy-seven children (47 males) were retrospectively studied, median age of 4 months. Mean length of hospital stay was 7.33 ± 0.16 days, 68.9% of patients received mechanical ventilation, 25.9% had oligo-anuria, and peritoneal dialysis was performed in 42.8%. The pRIFLE criteria were: injury (5.2%) and failure (94.8%), and the staging system criteria were: stage 1 (14.3%), stage 2 (29.9%), and stage 3 (55.8%). The mortality rate was 33.7%. In the multivariate analysis, the risk factors for mortality were PICU length of stay (OR = 0.615, SE = 0.1377, 95% CI = 0.469-0.805, p = 0.0004); invasive mechanical ventilation (OR = 14.599, SE = 1.1178, 95% CI = 1.673-133.7564, p = 0.0155); need for dialysis (OR = 9.714, SE = 0.8088, 95% CI = 1.990-47.410, p = 0.0049), and hypoalbuminemia (OR = 10.484, SE = 1.1147, 95% CI = 1.179-93.200, p = 0.035). Conclusions: The risk factors for mortality in children with acute kidney injury were associated with sepsis severity

Predictive factors of mortality in pediatric patients with acute renal injury associated with sepsis

Objective: To evaluate the prognosis factors of children with sepsis and acute kidney injury. Methods: This was a retrospective study of children with sepsis and acute kidney injury that were admitted to the pediatric intensive care unit (PICU) of a tertiary hospital. A multivariate analysis was performed to compare risk factors for mortality. Results: Seventy‐seven children (47 males) were retrospectively studied, median age of 4 months. Mean length of hospital stay was 7.33 ± 0.16 days, 68.9% of patients received mechanical ventilation, 25.9% had oligo‐anuria, and peritoneal dialysis was performed in 42.8%. The pRIFLE criteria were: injury (5.2%) and failure (94.8%), and the staging system criteria were: stage 1 (14.3%), stage 2 (29.9%), and stage 3 (55.8%). The mortality rate was 33.7%. In the multivariate analysis, the risk factors for mortality were PICU length of stay (OR = 0.615, SE = 0.1377, 95% CI = 0.469‐0.805, p = 0.0004); invasive mechanical ventilation (OR = 14.599, SE = 1.1178, 95% CI = 1.673‐133.7564, p = 0.0155); need for dialysis (OR = 9.714, SE = 0.8088, 95% CI =1990‐47.410, p = 0.0049), and hypoalbuminemia (OR = 10.484, SE =1.1147, 95% CI = 1.179‐93.200, p = 0.035). Conclusions: The risk factors for mortality in children with acute kidney injury were associated with sepsis severity

Enxertia e água de irrigação carbonatada no transporte de 15N e na produção do tomateiro Grafting and carbonated irrigation water in transport of 15N and in the tomato production

Estudaram-se os efeitos da aplicação de CO2, via água de irrigação, e da enxertia do tomateiro no transporte de 15N e na produção do tomateiro. Os tratamentos foram arranjados em delineamento inteiramente ao acaso no esquema fatorial 2 x 2 (com e sem CO2 na água de irrigação e tomateiro enxertado e pé-franco). A injeção do CO2 na água iniciou-se aos 34 dias após o transplante das mudas (DAT) e se prolongou em todas as irrigações. A aplicação do sulfato de amônio com abundância em átomos de 15N de 3,13% nas plantas destinadas à análise foi feita aos 45 DAT quando as plantas estavam em plena frutificação. Após 14 dias da aplicação do fertilizante (15N ) as plantas foram colhidas, lavadas, secadas e enviadas ao laboratório, para análise do 15N nos seus tecidos. Os resultados demonstraram que o CO2 e a enxertia não alteraram o transporte de 15N na planta. A produção de frutos comerciais foi maior quando se aplicou CO2 na água.<br>The effects of CO2 application through irrigation water, and of grafting in transport of 15N and in the tomato production, were studied. These treatments were arranged in a 2 x 2 factorial scheme (with and without CO2 in irrigation water and grafted and non-grafted tomato), in a completely randomized design, with four replications. The injection of CO2 into the water began at 34 days after transplant of seedlings (DAT) and continued for all irrigations. The application of the sulfate of ammonium with abundance in atoms of 15N of 3.13% in plants destined to analysis was done at 45 DAT when the plants were in the middle of fructification. After 14 days of fertilizer (15N ) application the plants were harvested, washed, dried and sent for analysis of 15N in plant tissue. The results demonstrated that CO2 and the grafting did not alter the transport of 15N in the plant. The production of commercial fruits was larger when CO2 was applied in water