Soybean crop area estimation by Modis/Evi data

The objective of this work was to develop a procedure to estimate soybean crop areas in Rio Grande do Sul state, Brazil. Estimations were made based on the temporal profiles of the enhanced vegetation index (Evi) calculated from moderate resolution imaging spectroradiometer (Modis) images. The methodology developed for soybean classification was named Modis crop detection algorithm (MCDA). The MCDA provides soybean area estimates in December (first forecast), using images from the sowing period, and March (second forecast), using images from the sowing and maximum crop development periods. The results obtained by the MCDA were compared with the official estimates on soybean area of the Instituto Brasileiro de Geografia e Estatística. The coefficients of determination ranged from 0.91 to 0.95, indicating good agreement between the estimates. For the 2000/2001 crop year, the MCDA soybean crop map was evaluated using a soybean crop map derived from Landsat images, and the overall map accuracy was approximately 82%, with similar commission and omission errors. The MCDA was able to estimate soybean crop areas in Rio Grande do Sul State and to generate an annual thematic map with the geographic position of the soybean fields. The soybean crop area estimates by the MCDA are in good agreement with the official agricultural statistics.

Estimation of Aedes aegypti (Diptera: Culicidae) population size and adult male survival in an urban area in Panama

Traditional mosquito control strategies rely heavily on the use of chemical insecticides. However, concerns about the efficiency of traditional control methods, environmental impact and emerging pesticide resistance have highlighted the necessity for developing innovative tools for mosquito control. Some novel strategies, including release of insects carrying a dominant lethal gene (RIDL®), rely on the sustained release of modified male mosquitoes and therefore benefit from a thorough understanding of the biology of the male of the species. In this report we present the results of a mark-release-recapture study aimed at: (i) establishing the survival in the field of laboratory-reared, wild-type male Aedes aegypti and (b) estimating the size of the local adult Ae. aegypti population. The study took place in Panama, a country where recent increases in the incidence and severity of dengue cases have prompted health authorities to evaluate alternative strategies for vector control. Results suggest a life expectancy of 2.3 days for released male mosquitoes (confidence interval: 1.78-2.86). Overall, the male mosquito population was estimated at 58 males/ha (range 12-81 males/ha), which can be extrapolated to an average of 0.64 pupae/person for the study area. The practical implications of these results are discussed.

Estimation of surface area and pore volume of activated carbons by methylene blue and iodine numbers

Data of methylene blue number and iodine number of activated carbons samples were calibrated against the respective surface area, micropore volume and total pore volume using multiple regression. The models obtained from the calibrations were used in predicting these physical properties of a test group of activated carbon samples produced from several raw materials. In all cases, the predicted values were in good agreement with the expected values. The method allows extracting more information from the methylene blue and iodine adsorption studies than normally obtained with this type of material.

Circulation of antibodies against yellow fever virus in a simian population in the area of Porto Primavera Hydroelectric Plant, São Paulo, Brazil

Yellow fever (YF) is an acute viral infectious disease transmitted by mosquitoes which occurs in two distinct epidemiological cycles: sylvatic and urban. In the sylvatic cycle, the virus is maintained by monkey's infection and transovarian transmission in vectors. Surveillance of non-human primates is required for the detection of viral circulation during epizootics, and for the identification of unaffected or transition areas. An ELISA (enzyme-linked immunosorbent assay) was standardized for estimation of the prevalence of IgG antibodies against yellow fever virus in monkey sera (Alouatta caraya) from the reservoir area of Porto Primavera Hydroelectric Plant, in the state of São Paulo, Brazil. A total of 570 monkey sera samples were tested and none was reactive to antibodies against yellow fever virus. The results corroborate the epidemiology of yellow fever in the area. Even though it is considered a transition area, there were no reports to date of epizootics or yellow fever outbreaks in humans. Also, entomological investigations did not detect the presence of vectors of this arbovirus infection. ELISA proved to be fast, sensitive, an adequate assay, and an instrument for active search in the epidemiological surveillance of yellow fever allowing the implementation of prevention actions, even before the occurrence of epizootics.

Estimation of Genetic Divergence and Gene Flow between Culex pipiens and Culex quinquefasciatus (Diptera: Culicidae) in Argentina

Allele frequencies at seven polymorphic loci controlling the synthesis of enzymes were analyzed in six populations of Culex pipiens L. and Cx. quinquefasciatus Say. Sampling sites were situated along a north-south line of about 2,000 km in Argentina. The predominant alleles at Mdh, Idh, Gpdh and Gpi loci presented similar frequencies in all the samples. Frequencies at the Pgm locus were similar for populations pairs sharing the same geographic area. The loci Cat and Hk-1 presented significant geographic variation. The latter showed a marked latitudinal cline, with a frequency for allele b ranging from 0.99 in the northernmost point to 0.04 in the southernmost one, a pattern that may be explained by natural selection (FST = 0.46; p < 0.0001) on heat sensitive alleles. The average value of FST (0.088) and Nm (61.12) indicated a high gene flow between adjacent populations. A high correlation was found between genetic and geographic distance (r = 0.83; p < 0.001). The highest genetic identity (IN = 0.988) corresponded to the geographically closest samples from the central area. In one of these localities Cx. quinquefasciatus was predominant and hybrid individuals were detected, while in the other, almost all the specimens were identified as Cx. pipiens. To verify the fertility between Cx. pipiens and Cx. quinquefasciatus from the northern- and southernmost populations, experimental crosses were performed. Viable egg rafts were obtained from both reciprocal crosses. Hatching ranged from 76.5 to 100%. The hybrid progenies were fertile through two subsequent generations

Drosophilids (Diptera) from an Atlantic Forest Area in Santa Catarina, Southern Brazil

The present work aims at knowing the faunal composition of drosophilids in forest areas of southern Brazil. Besides, estimation of species richness for this fauna is briefly discussed. The sampling were carried out in three well-preserved areas of the Atlantic Rain Forest in the State of Santa Catarina. In this study, 136,931 specimens were captured and 96.6% of them were identified in the specific level. The observed species richness (153 species) is the largest that has been registered in faunal inventories conducted in Brazil. Sixty-three of the captured species did not fit to the available descriptions, and we believe that most of them are non-described species. The incidence-based estimators tended to give rise to the largest richness estimates while the abundance based give rise to the smallest ones. Such estimators suggest the presence from 172.28 to 220.65 species in the studied area. Based on these values, from 69.35 to 88.81% of the expected species richness were sampled. We suggest that the large richness recorded in this study is a consequence of the large sampling effort, the capture method, recent advances in the taxonomy of drosophilids, the high preservation level and the large extension of the sampled fragment and the high complexity of the Atlantic Rain forest. Finally, our data set suggest that the employment of estimators of richness for drosophilid assemblages is useful but it requires caution.

The efficiency of different estimation methods of hydro-physical limits

The soil water available to crops is defined by specific values of water potential limits. Underlying the estimation of hydro-physical limits, identified as permanent wilting point (PWP) and field capacity (FC), is the selection of a suitable method based on a multi-criteria analysis that is not always clear and defined. In this kind of analysis, the time required for measurements must be taken into consideration as well as other external measurement factors, e.g., the reliability and suitability of the study area, measurement uncertainty, cost, effort and labour invested. In this paper, the efficiency of different methods for determining hydro-physical limits is evaluated by using indices that allow for the calculation of efficiency in terms of effort and cost. The analysis evaluates both direct determination methods (pressure plate - PP and water activity meter - WAM) and indirect estimation methods (pedotransfer functions - PTFs). The PTFs must be validated for the area of interest before use, but the time and cost associated with this validation are not included in the cost of analysis. Compared to the other methods, the combined use of PP and WAM to determine hydro-physical limits differs significantly in time and cost required and quality of information. For direct methods, increasing sample size significantly reduces cost and time. This paper assesses the effectiveness of combining a general analysis based on efficiency indices and more specific analyses based on the different influencing factors, which were considered separately so as not to mask potential benefits or drawbacks that are not evidenced in efficiency estimation.

Estimation of soil moisture in the root-zone from remote sensing data

Field-based soil moisture measurements are cumbersome. Thus, remote sensing techniques are needed because allows field and landscape-scale mapping of soil moisture depth-averaged through the root zone of existing vegetation. The objective of the study was to evaluate the accuracy of an empirical relationship to calculate soil moisture from remote sensing data of irrigated soils of the Apodi Plateau, in the Brazilian semiarid region. The empirical relationship had previously been tested for irrigated soils in Mexico, Egypt, and Pakistan, with promising results. In this study, the relationship was evaluated from experimental data collected from a cotton field. The experiment was carried out in an area of 5 ha with irrigated cotton. The energy balance and evaporative fraction (Λ) were measured by the Bowen ratio method. Soil moisture (θ) data were collected using a PR2 - Profile Probe (Delta-T Devices Ltd). The empirical relationship was tested using experimentally collected Λ and θ values and was applied using the Λ values obtained from the Surface Energy Balance Algorithm for Land (SEBAL) and three TM - Landsat 5 images. There was a close correlation between measured and estimated θ values (p<0.05, R² = 0.84) and there were no significant differences according to the Student t-test (p<0.01). The statistical analyses showed that the empirical relationship can be applied to estimate the root-zone soil moisture of irrigated soils, i.e. when the evaporative fraction is greater than 0.45.

Estimation of transpiration of the 'Valencia' orange young plant using thermal dissipation probe method

Most studies on measures of transpiration of plants, especially woody fruit, relies on methods of heat supply in the trunk. This study aimed to calibrate the Thermal Dissipation Probe Method (TDP) to estimate the transpiration, study the effects of natural thermal gradients and determine the relation between outside diameter and area of xylem in 'Valencia' orange young plants. TDP were installed in 40 orange plants of 15 months old, planted in boxes of 500 L, in a greenhouse. It was tested the correction of the natural thermal differences (DTN) for the estimation based on two unheated probes. The area of the conductive section was related to the outside diameter of the stem by means of polynomial regression. The equation for estimation of sap flow was calibrated having as standard lysimeter measures of a representative plant. The angular coefficient of the equation for estimating sap flow was adjusted by minimizing the absolute deviation between the sap flow and daily transpiration measured by lysimeter. Based on these results, it was concluded that the method of TDP, adjusting the original calibration and correction of the DTN, was effective in transpiration assessment.

Estimation of evaporation in the Banabuiú dam, in the state of Ceará, Brazil, by different combined methods, derived from the Penman equation

The state of Ceará, Brazil, has 75% of its area covered by Brazilian semiarid, with its peculiar features. In this state, the dams are constituted in water structure of strategic importance, ensuring, both in time and space, the development and supply of water to population. However, construction of reservoirs results in various impacts that should be carefully observed when deciding on their implementation. One of the impacts identified as negative is the increased evaporation, which constitutes a major component of water balance in reservoirs, especially in arid regions. Several methods for estimating evaporation have been proposed over time, many of them deriving from the Penman equation. This study evaluated six different methods for estimating evaporation in order to determine the most suitable for use in hydrological models for water balance in reservoirs in the state of Ceará. The tested methods were proposed by Penman, Kohler-Nordenson-Fox, Priestley-Taylor, deBruim-Keijman, Brutsaert-Stricker and deBruim. The methods presented good performance when tested for water balance during the dry season, and the Priestley-Taylor was the most appropriate, since the data from de simulated water balance with evaporation estimated by this method were the closest of the water balance data observed from measures of reservoir level and the elevation-volume curve provided by the Company of Management of Water Resources of the state of Ceará - COGERH.

Estimation of alluvial recharge in the semiarid

In areas where there is irrigated agriculture, the recuperation of water reserves in alluvial aquifers may occur preferentially due to precipitation. Recharging can be evaluated from variation information of water depth measured in piezometers or observation wells. Thus, the aim of this research is to study the recharge in the alluvial aquifer formed by the Mimoso temporary stream in the semiarid region of Pernambuco (PE), Brazil, using the method of the fluctuation of the water level. This system is typical on the Brazilian Northeast semiarid region, using groundwater for domestic supply and for irrigation on small scale agriculture. Monthly potentiometric levels and rainfall data were used. The selected period for the study, from January 2002 to October 2009, involved extreme events of flooding and droughts as well as regular years, providing a better understanding of the behavior of the alluvial recharge. It was found that the system responds significantly to precipitation events. It was also observed that even with different soil textures in the study area, recharge factors were not significantly different. The study provided a better understanding of the behavior of aquifer recharge and its relationship with the soil and the rainfall events in the region.

Nasolaringoscopia ou laringotraqueoscopia: qual o melhor exame para avaliação da via aérea infantil?

É comum crianças com quadro de desconforto respiratório alto, sendo importante uma avaliação através de endoscopia da via aérea. OBJETIVO: Avaliar qual o melhor exame para via aérea infantil. MATERIAIS E MÉTODOS: Estudo retrospectivo com 16 crianças do ambulatório de via aérea infantil do Setor de Otorrinolaringologia Pediátrica da UNICAMP, com história de stress respiratório, submetidas à nasolaringoscopia e laringotraqueoscopia de março de 2001 a março de 2004. Dados coletados foram equiparados e comparados. RESULTADOS: Foram avaliadas 16 crianças, sendo a indicação mais comum do exame avaliação de traqueotomia prolongada em 10 pacientes (62%), seguida de avaliação de estenose subglótica em três casos (31,3%). Em 44% dos exames houve falha da NL em mostrar lesões em subglote. CONCLUSÃO: A avaliação endoscópica da via aérea infantil em crianças com dificuldade respiratória é essencial para o diagnóstico. Concluímos que todas as crianças com patologia de via aérea superior devem ser submetidas à nasolaringoscopia inicialmente, a qual é um exame barato, de fácil execução e que fornece dados importantes inclusive a respeito da funcionalidade da laringe. No entanto, se houver suspeita de patologia subglótica ou traqueal, ou ainda quando os dados nasolaringoscopia não são condizentes com exame físico, é essencial a realização da laringotraqueoscopia.

Estudo dos limiares eletrofisiológicos das vias aérea e óssea em crianças com até 2 meses de idade

O diagnóstico diferencial de perdas auditivas com potencial evocado auditivo de tronco encefálico por via aérea e por via óssea em crianças pequenas tem sido pouco estudado no Brasil. OBJETIVO: Comparar as respostas do potencial evocado auditivo de tronco encefálico por vias aérea e óssea em crianças de até 2 meses de idade sem perdas auditivas. FORMA DE ESTUDO: Clínico prospectivo com coorte transversal. MATERIAL E MÉTODO: Foram avaliadas 12 crianças que passaram na triagem auditiva, por meio do potencial evocado auditivo de tronco encefálico por via aérea e via óssea. A via óssea foi realizada sem mascaramento contralateral. As respostas foram comparadas e analisadas por meio do teste de McNemar e pela análise de variância com medidas repetidas. RESULTADOS: Não houve diferença estatística no limiar eletrofisiológico por via aérea e via óssea (p>0,05). O tempo de latência por via óssea foi estatisticamente maior do que o tempo de latência por via aérea (p=0,000). CONCLUSÃO: Houve concordância no registro do Potencial Evocado Auditivo de Tronco Encefálico captado por vias aérea e óssea nas intensidades próximas ao limiar auditivo; a latência da onda V registrada por via óssea foi estatisticamente maior que a registrada por via aérea.

Avaliação da obstrução da via aérea superior através da videonasofaringoscopia: comparação da manobra de Müller com o sono induzido

A nasofaringoscopia com realização de Manobra de Müller é freqüentemente utilizada para determinar o local da obstrução na via aérea superior. No entanto, sua utilidade é controversa, uma vez que é realizada com o paciente acordado e pode não reproduzir os fenômenos obstrutivos que ocorrem durante o sono. OBJETIVOS: Comparar o grau de obstrução faríngea nas regiões retropalatal e retrolingual que ocorrem durante a manobra de Müller com aquelas que ocorrem durante o sono induzido. MATERIAL E MÉTODOS: Estudo prospectivo de 8 pacientes (3 homens e 5 mulheres) com idade (média ±desvio padrão) de 48,6 ± 9,2 anos de idade através de videonasofaringoscopia durante a manobra de Müller e durante o sono induzido por midazolam endovenoso. RESULTADOS: Observamos obstrução retropalatal similar durante a manobra de Müller e sono induzido (média + desvio padrão 3,13 + 0,99 e 2,75 + 0,46, respectivamente, p= 0,234). Em contraste, a obstrução retrolingual foi significantemente menor durante a manobra de Müller (média + desvio padrão 0,63 + 1,06 e 2,63 + 1,30, respectivamente, p= 0,005). CONCLUSÃO: O método do sono induzido foi seguro sob as condições de monitorização adotadas, tendo detectado maior ocorrência de colapso retrolingual do que a manobra de Müller.

The effect of leaf area reduction on corn plants during the reproduction phase

Reduction in leaf area in corn plants during reproduction changes physiological metabolism and consequently the accumulation of dry matter in grains. The aim of this work was to study changes in agronomic characteristics caused by defoliation in corn during the reproduction phase. The experiment was carried out in Uberlândia, Minas Gerais state, in the agricultural year 2007/2008. The experiment was arranged in a randomized block design, consisting of seven treatments: control without defoliation, removal of two apical leaves, removal of four apical leaves, removal of all leaves above spike, removal of four intermediate leaves, removal of all leaves below spike, and removal of all plant leaves, with five repetitions. The genotype used for the evaluations was hybrid NB 7376. Defoliation was carried out when plants were at the growth stage R2. The variables assessed were: yield, density of spikes and corncobs, root resistance and stem integrity. When all leaves above the spike were removed, grain yield was reduced by 20%. Corncob density, stem integrity and root resistance to uprooting were also affected. Spike density was only affected when all plant leaves were removed. The leaf area remaining physiologically active above the spike was found to be most efficient in terms of grain yield.