Métodos para avaliar a qualidade fisiológica de sementes de arroz

Aiming to evaluate the efficiency of different methods to determine the physiological quality of rice seeds, two groups of 10 lots each of the varieties BR-IRGA 409 and BR-IRGA 410 were used. Seed quality was determined through seed water content, weight of 1,000 seeds, germination and vigor tests: first germination counting, classification of seedling vigor, accelerated aging, modified cold test, seedling growth and weight and field emergence. It was concluded that the modified cold test and classification of seedling vigor are capable of stratifying different rice samples according to their vigor and are positively correlated with field emergence. The accelerated aging, under 42'C and 100% relative humidity of air conditions stratifies the samples in relation to seed vigor. The tests of seedling growth and weight, when eliminating abnormal seedlings and non-germinated seeds, are not capable of stratifying rice seed samples as a function of seed vigor.Com o objetivo de avaliar a eficiência de diferentes métodos para a determinação da qualidade fisiológica de sementes de arroz, foram utilizados dois grupos de dez lotes de sementes, das variedades BR-IRGA 409 e BR-IRGA 410. A qualidade dos lotes foi determinada através do teor de água, peso de mil sementes, teste de germinação e dos testes de vigor: primeira contagem de germinação, classificação do vigor de plântulas, envelhecimento acelerado, teste de frio modificado, tamanho e massa seca de plântulas e emergência no campo. Concluiu-se que os testes de frio modificado e classificação do vigor de plântulas são capazes de estratificar diferentes lotes de arroz pelo vigor e se correlacionam positivamente com a emergência no campo. O teste de envelhecimento acelerado, sob as condições de 42'C e 100% de umidade relativa do ar, durante 120 horas, estratifica lotes de arroz , em função do vigor das sementes. Os testes de tamanho e massa seca de plântulas, quando eliminam as plântulas anormais e sementes não germinadas, não são capazes de estratificar lotes de sementes de arroz, em função do vigor

Efeito do tratamento com fontes de zinco e boro na germinação e vigor de sementes de milho

The experiment was carried during the period of march 1992 to november 1992, to study the effects of maize seed treatment with zinc, boron and pesticides, on the germination and vigour during storage. The experimental design was a complete randomized 3x2x6 fatorial with four replicátions. The treatments were three storage periods (zero, four and eight month), pesticides treatments with or without, and six sources of zinc and boron (control, Zn-Biocrop, B-Biocrop, Organic-B, Zn-Biocrop -I- B-Biocrop and Zn-Biocrop + Organic-B), in the dose 2.50g of the Zn and 0.l5g of the B/kg of seeds. The results show that Zn-Biocrop maintain high germination and vigour for eight month of storage. The boron treatment (B-Biocrop and Organic-B) showed a low germination and vigour.Foi conduzido um experimento no Departamento de Fitotecnia da Universidade Federal de Santa Maria, RS, no período de março a novembro de 1992, com o objetivo de verificar o efeito da aplicação de fontes de zinco e boro em sementes de milho tratadas ou não com defensivos agrícolas. Adotou-se o esquema fatorial 3x2x6, em delineamento inteiramente casualizado, com quatro repetições. Os tratamentos constaram de avaliações em três épocas (logo após o tratamento, quatro e oito meses depois), utilização de sementes de milho com e sem tratamento fítossanitário, combinados com seis fontes de zinco e boro (testemunha, Zn-Biocrop, B-Biocrop, E-Orgânico, Zn-Biocrop + B-Biocrop e Zn-Biocrop + B-Orgânico), nas doses únicas de 2,50g Zn e de 0,15g B/kg de sementes. Os resultados obtidos mostram que a aplicação da fonte Zn-Biocrop não prejudica a germinação e o vigor, pelo período de oito meses de armazenamento. O tratamento de sementes com boro (B-Biocrop e B-Orgânico) diminui a germinação e o vigor

Differential influences of early growth and social factors on young children's cognitive performance in four low-and-middle-income birth cohorts (Brazil, Guatemala, Philippines, and South Africa)

Background: Studies relating childhood cognitive development to poor linear growth seldom take adequate account of social conditions related to both, leading to a focus on nutrition interventions. We aimed to assess the roles of both biological and social conditions in determining early childhood cognition, mediated by birthweight and early linear growth. Methods: After exploratory structural equation modelling to identify determining factors, we tested direct and indirect paths to cognitive performance through birthweight and child height-for-age at 2 years, assessed between 4 and 8.5 years of age among 2448 children in four birth cohort studies in low-and-middle-income countries (Brazil, Guatemala, Philippines and South Africa). Determinants were compared across the cohorts. Findings: Three factors yielded excellent fit, comprising birth endowment (primarily maternal age and birth order), household resources (crowding, dependency) and parental capacity (parental education). We estimated their strength together with maternal height in determining cognitive performance. Percentage shares of total effects of the four determinants show a marked transition from mainly biological determinants of birth weight (birth endowment 34%) and maternal height (30%) compared to household resources (25%) and parental capacity (11%), through largely economic determinants of height at 2 years (household resources (60%) to cognitive performance being predominantly determined by parental capacity (64%) followed by household resources (29%). The largely biological factor, birth endowment (maternal age and birth order) contributed only 7% to childhood cognitive performance and maternal height was insignificant. In summary, the combined share of social total effects (household resources and parental capacity) rises from 36∙2% on birth weight, to 78∙2% on height for age at 24 m, and 93∙4% on cognitive functioning. Interpretation: Across four low- and middle-income contexts, cognition in childhood is influenced more by the parental capacity of families and their economic resources than by birth weight and early linear growth. Improving children's cognitive functioning requires multi-sectoral interventions to improve parental education and enhance their economic wellbeing, interventions that are known to improve also early childhood growth

On Asymptotic Expansion in the Random Allocation of Particles by Sets

We consider a scheme of equiprobable allocation of particles into cells by sets. The Edgeworth type asymptotic expansion in the local central limit theorem for a number of empty cells left after allocation of all sets of particles is derived.Comment: 15 page

Mapping geographical inequalities in childhood diarrhoeal morbidity and mortality in low-income and middle-income countries, 2000–17 : analysis for the Global Burden of Disease Study 2017

Background Across low-income and middle-income countries (LMICs), one in ten deaths in children younger than 5 years is attributable to diarrhoea. The substantial between-country variation in both diarrhoea incidence and mortality is attributable to interventions that protect children, prevent infection, and treat disease. Identifying subnational regions with the highest burden and mapping associated risk factors can aid in reducing preventable childhood diarrhoea. Methods We used Bayesian model-based geostatistics and a geolocated dataset comprising 15 072 746 children younger than 5 years from 466 surveys in 94 LMICs, in combination with findings of the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017, to estimate posterior distributions of diarrhoea prevalence, incidence, and mortality from 2000 to 2017. From these data, we estimated the burden of diarrhoea at varying subnational levels (termed units) by spatially aggregating draws, and we investigated the drivers of subnational patterns by creating aggregated risk factor estimates. Findings The greatest declines in diarrhoeal mortality were seen in south and southeast Asia and South America, where 54·0% (95% uncertainty interval [UI] 38·1–65·8), 17·4% (7·7–28·4), and 59·5% (34·2–86·9) of units, respectively, recorded decreases in deaths from diarrhoea greater than 10%. Although children in much of Africa remain at high risk of death due to diarrhoea, regions with the most deaths were outside Africa, with the highest mortality units located in Pakistan. Indonesia showed the greatest within-country geographical inequality; some regions had mortality rates nearly four times the average country rate. Reductions in mortality were correlated to improvements in water, sanitation, and hygiene (WASH) or reductions in child growth failure (CGF). Similarly, most high-risk areas had poor WASH, high CGF, or low oral rehydration therapy coverage. Interpretation By co-analysing geospatial trends in diarrhoeal burden and its key risk factors, we could assess candidate drivers of subnational death reduction. Further, by doing a counterfactual analysis of the remaining disease burden using key risk factors, we identified potential intervention strategies for vulnerable populations. In view of the demands for limited resources in LMICs, accurately quantifying the burden of diarrhoea and its drivers is important for precision public health