Aline de Holanda Nunes Maia

Statistical Inference on Associated Fertility Life Table Parameters Using Jackknife Technique: Computational Aspects

Abstract Knowledge of population growth potential is crucial for studying population dynamics and for establishing management tactics for pest control. Estimation of population growth can be achieved with fertility life tables because they synthesize data on reproduction and mortality of a population. The five main parameters associated with a fertility life table are as follows: (1) the net reproductive rate (Ro), (2) the intrinsic rate of increase (rm), 3) the mean generation time (T), (4) the doubling time (Dt), and (5) the finite rate of increase (λ). Jackknife and bootstrap techniques are used to calculate the variance of the rm estimate, which can be extended to the other parameters of life tables. Those methods are computer-intensive, their application requires the development of efficient algorithms, and their implementation is based on a programming language that encompasses quickness and reliability. The objectives of this article are to discuss statistical and computational aspects related to estimation of life table parameters and to present a SAS program that uses jackknife to estimate parameters for fertility life tables. The SAS program presented here allows the calculation of confidence intervals for all estimated parameters, as well as provides one-sided and two-sided t-tests to perform pairwise or multiple comparison between groups, with their respective P values.

Near‐global impact of the Madden‐Julian Oscillation on rainfall

The accuracy of synoptic-based weather forecasting deteriorates rapidly after five days and is not routinely available beyond 10 days. Conversely, climate forecasts are generally not feasible for periods of less than 3 months, resulting in a weather-climate gap. The tropical atmospheric phenomenon known as the Madden-Julian Oscillation (MJO) has a return interval of 30 to 80 days that might partly fill this gap. Our near-global analysis demonstrates that the MJO is a significant phenomenon that can influence daily rainfall patterns, even at higher latitudes, via teleconnections with broadscale mean sea level pressure (MSLP) patterns. These weather states provide a mechanistic basis for an MJO-based forecasting capacity that bridges the weather-climate divide. Knowledge of these tropical and extra-tropical MJO-associated weather states can significantly improve the tactical management of climate-sensitive systems such as agriculture.

Fish exposure to nano-TiO2 under different experimental conditions: Methodological aspects for nanoecotoxicology investigations

The ecotoxicology of nano-TiO2 has been extensively studied in recent years; however, few toxicological investigations have considered the photocatalytic properties of the substance, which can increase its toxicity to aquatic biota. The aim of this work was to evaluate the effects on fish exposed to different nano-TiO2 concentrations and illumination conditions. The interaction of these variables was investigated by observing the survival of the organisms, together with biomarkers of biochemical and genetic alterations. Fish (Piaractus mesopotamicus) were exposed for 96 h to 0, 1, 10, and 100 mg/L of nano-TiO2, under visible light, and visible light with ultraviolet (UV) light (22.47 J/cm(2)/h). The following biomarkers of oxidative stress were monitored in the liver: concentrations of lipid hydroperoxide and carbonylated protein, and specific activities of superoxide dismutase, catalase, and glutathione S-transferase. Other biomarkers of physiological function were also studied: the specific activities of acid phosphatase and Na,K-ATPase were analyzed in the liver and brain, respectively, and the concentration of metallothionein was measured in the gills. In addition, micronucleus and comet assays were performed with blood as genotoxic biomarkers. Nano-TiO2 caused no mortality under any of the conditions tested, but induced sublethal effects that were influenced by illumination condition. Under both illumination conditions tested, exposure to 100 mg/L showed an inhibition of acid phosphatase activity. Under visible light, there was an increase in metallothionein level in fish exposed to 1 mg/L of nano-TiO2. Under UV light, protein carbonylation was reduced in groups exposed to 1 and 10 mg/L, while nucleus alterations in erythrocytes were higher in fish exposed to 10 mg/L. As well as improving the understanding of nano-TiO2 toxicity, the findings demonstrated the importance of considering the experimental conditions in nanoecotoxicological tests. This work provides information for the development of protocols to study substances whose toxicity is affected by illumination conditions.

Evaluation of the diversity of rhizobia in Brazilian agricultural soils cultivated with soybeans

The diversity of rhizobia in agricultural soils planted with soybean (Glycine max L.) and managed under conventional or notillage practices was evaluated by using a combination of trap-host capture and DNA fingerprinting approaches. Fifty-eight rhizobia isolates were captured using pigeonpea (Cajanus cajan L.) as a trap-host and characterised by using the RAPD DNA fingerprinting technique, yielding 25 different RAPD profiles. The application of the Shannon‐Weaver diversity index demonstrated that the diversity of rhizobia was significantly reduced in soil samples from plots cultivated with soybean compared with original uncultivated pasture plots. # 1999 Elsevier Science B.V. All rights reserved.

Características químicas e físico-químicas de pequis da Chapada do Araripe, Ceará

O objetivo deste trabalho foi avaliar a qualidade do pequi. Para isso, frutos maduros colhidos de trinta e cinco pequizeiros (Cariocar coriaceum Wittm.) nativos, provenientes da Chapada do Araripe, Estado do Ceara, foram avaliados quanto as suas caracteristicas quimicas e fisico-quimicas. Na polpa do fruto, foram determinados pH, acidez total titulavel (ATT), solidos soluveis (°Brix), acucares soluveis totais (AST), relacao °Brix/acidez, atividade de agua, proteina, carboidratos totais e valor energetico total; na polpa e amendoa, umidade, lipidios, cinzas e minerais (Ca, Mg, P, K, Cu, Fe, Mn, Na e Zn). As plantas apresentaram grande variabilidade para a maioria das caracteristicas avaliadas. As maiores variabilidades foram observadas para a acidez, acucares totais e proteina. Em relacao aos minerais, a maior variabilidade foi observada para o cobre na polpa e sodio na amendoa. A menor variabilidade foi detectada para a atividade de agua, pH e umidade da polpa, em ordem crescente. Seis plantas destacaram- se por apresentarem percentagem de lipidios (polpa e amendoa) superiores a media deste estudo. A composicao em minerais variou entre as amostras (onze plantas), destacando-se, em termos quantitativos, o potassio na polpa e o fosforo na amendoa. A amendoa e mais rica em minerais do que a polpa. A polpa do pequi, face as caracteristicas de baixa acidez, alto pH e alta atividade de agua, apresenta-se propicia ao desenvolvimento de microrganismos patogenicos e a deterioracao. Alem disso, a presenca de nutrientes, temperatura e a disponibilidade de oxigenio sao fatores importantes que devem ser considerados durante o processamento e armazenamento por favorecerem a oxidacao dos lipidios. Os resultados demonstram a importância nutricional do pequi, principalmente de sua amendoa, pelo elevado teor de lipidios e minerais.

Inferential, Nonparametric Statistics to Assess the Quality of Probabilistic Forecast Systems

Many statistical forecast systems are available to interested users. In order to be useful for decision-making, these systems must be based on evidence of underlying mechanisms. Once causal connections between the mechanism and their statistical manifestation have been firmly established, the forecasts must also provide some quantitative evidence of `quality’. However, the quality of statistical climate forecast systems (forecast quality) is an ill-defined and frequently misunderstood property. Often, providers and users of such forecast systems are unclear about what ‘quality’ entails and how to measure it, leading to confusion and misinformation. Here we present a generic framework to quantify aspects of forecast quality using an inferential approach to calculate nominal significance levels (p-values) that can be obtained either by directly applying non-parametric statistical tests such as Kruskal-Wallis (KW) or Kolmogorov-Smirnov (KS) or by using Monte-Carlo methods (in the case of forecast skill scores). Once converted to p-values, these forecast quality measures provide a means to objectively evaluate and compare temporal and spatial patterns of forecast quality across datasets and forecast systems. Our analysis demonstrates the importance of providing p-values rather than adopting some arbitrarily chosen significance levels such as p < 0.05 or p < 0.01, which is still common practice. This is illustrated by applying non-parametric tests (such as KW and KS) and skill scoring methods (LEPS and RPSS) to the 5-phase Southern Oscillation Index classification system using historical rainfall data from Australia, The Republic of South Africa and India. The selection of quality measures is solely based on their common use and does not constitute endorsement. We found that non-parametric statistical tests can be adequate proxies for skill measures such as LEPS or RPSS. The framework can be implemented anywhere, regardless of dataset, forecast system or quality measure. Eventually such inferential evidence should be complimented by descriptive statistical methods in order to fully assist in operational risk management.

Estimativa da deposição de agrotóxicos por análise de gotas

The available methodologies for analysing the pesticide reaching the target are sophisticated or expensive. The objective of this work was to compare two methods to quantify the pesticide deposition. One of them by droplets analysis and the other by chemical tracer analysis. The droplets of a fungicide spray were sampled using water sensitive papers, slides with oxide magnesium and cards of filter paper. In the droplet analysis method, the volume of spray deposited on a delimited area was estimated considering the diameters of stains or craters, spread factors and droplet density. In the chemical tracer analysis method the volume was calculated by the residue deposited on sampling target and spray concentration. There were no statistic differences in the volumes estimated by the two methods.

Sensitivity of APSIM/ORYZA model due to estimation errors in solar radiation

Crop models are ideally suited to quantify existing climatic risks. However, they require historic climate data as input. While daily temperature and rainfall data are often available, the lack of observed solar radiation (Rs) data severely limits site-specific crop modelling. The objective of this study was to estimate Rs based on air temperature solar radiation models and to quantify the propagation of errors in simulated radiation on several APSIM/ORYZA crop model seasonal outputs, yield, biomass, leaf area (LAI) and total accumulated solar radiation (SRA) during the crop cycle. The accuracy of the 5 models for estimated daily solar radiation was similar, and it was not substantially different among sites. For water limited environments (no irrigation), crop model outputs yield, biomass and LAI was not sensitive for the uncertainties in radiation models studied here.

Caracterização física de frutos do pequizeiro nativos da chapada do Araripe-CE

The study aimed to characterize physically pequi fruits (Caryocar coriaceum Wittm.) of native trees from Chapada do Araripe, situated south of the state of Ceara, in order to quantify the variability among plants and identify genotypes to food industry and breeding programs. Fruits of 35 plants were characterized for 24 physical parameters in the whole fruit, rind, almonds, pulp and seeds. The results (average of 25 fruits) were evaluated via descriptive statistics (measures of central trend and data variability) and methods of multivariate analysis (cluster analysis and main component analysis). The fruits from the plants numbers: 01, 02, 03, 05, 07; 14, 22 and 26 showed the best characteristics for processing. The cluster analysis resulted in the identification of five groups of plants with similar phenotypic characteristics. The results showed that there is considerable variability in the specie.

Bioconcentration factor estimates of polycyclic aromatic hydrocarbons in grains of corn plants cultivated in soils treated with sewage sludge

This study presents a model to simulate the organic substance concentrations in corn grains assuming that the substances in soil solution are absorbed via the transpiration stream by plants growing in soils fertilized with sewage sludge (SS). The model was applied and validated using soil and corn grain samples from a long-term field experiment with six successive yearly applications of SS to the soil. The following polycyclic aromatic hydrocarbons (PAHs) were simulated and evaluated in soil and grain samples: acenaphthene, acenaphthylene, anthracene, benz(a)anthracene, benz(a)pyrene, benz(b)fluoranthene, benz(g,h,i)perylene, benz(k)fluoranthene, chrysene, dibenz(a,h)anthracene, fluoranthene, fluorene, indeno(1,2,3-c,d)pyrene, naphthalene, phenanthrene and pyrene. The PAH bioconcentration factors (BCF) in corn grains ranged from 1.57 to 10.97 L kg(-1). Polycyclic aromatic hydrocarbons with low soil distribution coefficients and high values of transpiration stream concentration factors (TSCF) are more likely to be absorbed by corn plants and accumulated in grains. It was possible to estimate and observe that highly lipophilic PAH molecules (heavy PAHs) show lower accumulative potential in corn grains than the less lipophilic ones (light PAHs). Sewage sludges containing significant concentrations of light PAHs with two, three or four benzene rings should be avoided as fertilizers in alimentary field crops.