Descrição e discriminação de formas de nervuras foliares utilizando a representação polinomial cúbica de Hermite

This paper describes a method for leaf vein shape characterization using Hermite polynomial cubic representation. The elements associated with this representation are used as secondary vein descriptors and their discriminatory potential are analyzed based on the identification of two legume species (Lonchocarpus muehlbergianus Hassl. and L. subglaucescens Mart, ex Benth.). The elements of Hermite geometry influence a curve along all its extension allowing a global description of the secondary vein course by a descriptor of low dimensionality. The obtained results shown the analyzed species can be discriminated by this method and it can be used in addition to commonly considered elements in the taxonomic process.

Folhas verdes, folhas secas, fibra do colmo e a clarificação do caldo de cana-de-açúcar

The presence of vegetal impurities in sugarcane delivered to sugarmills as green and dry leaves is a problem not only because they are non-value materials to be processed along with sugarcane stalks, but also because they can rise the color of the clarified juice and, consequently, the color of the sugar produced, with a reduction of its quality for the market. Another problem is the mud volume sedimented in the clarifiers, which also can result in a larger recirculation and greater volume of filtrate juice, with higher losses of sucrose and utilization of the vacuum rotary filters. The objective of this work was to observe the effect of the presence of green and dry leaves on sugarcane juice clarification, related to a control treatment with the addition of fiber extracted from the stalks. The experiments were planned based on the addition of quantities of fibrous sources in order to formulate samples with absolute increase of 0.25 , 0.50 and 0.75 percentual points over the fiber content of the sugarcane stalks (control treatment). The juice clarification was conducted with a laboratory clarifier. The clarified juice color and the mud volume were evaluated. The presence of green leaves caused higher color and mud volume due to the extraction of non-sucrose components of the leaves. Soluble compounds of dry leaves were also extracted, though not detected by juice analysis. The addition of the fiber extracted from the stalks did not induce alterations in the clarification process.

Produção de massa seca, relação folha/colmo e alguns índices de crescimento do Brachiaria brizantha cv. Xaraés cultivado com a combinação de doses de nitrogênio e potássio

Objetivou-se avaliar a produção de massa seca das folhas, a relação folha/colmo e alguns índices de crescimento do capim-xaraés submetido a doses de nitrogênio (N) e potássio (K). O experimento foi conduzido em casa-de-vegetação no período de novembro/2004 a fevereiro/2005. Adotou-se esquema fatorial 4 ´ 3, perfazendo 12 combinações, as quais foram distribuídas em delineamento experimental inteiramente casualizado, com quatro repetições, perfazendo um total 48 unidades experimentais. Foram utilizadas quatro doses de N (0, 75, 150 e 225 mg dm-3) e três doses de K (0, 50 e 100 mg dm-3). Verificou-se efeito das doses de N na produção de massa seca das folhas e na produção de massa seca total, em todos os cortes, com maior produção nas doses mais elevadas de N, ao passo que o K influenciou essas variáveis apenas no segundo corte. A relação folha/colmo, a RAF, a AFE e a RPF somente foram significativas no terceiro corte da planta. Os efeitos das doses de foram decrescentes sobre essas variáveis, enquanto as doses de K agiram de modo antagônico às doses de N sobre a RAF e AFE.

Isotopic view of vegetation and carbon and nitrogen cycles in a cerrado ecosystem, southeastern Brazil

Carbon and nitrogen biogeochemical cycles in savannas are strongly regulated by the seasonal distribution of precipitation and pulses of nutrients released during the wetting of the dry soil and are critical to the dynamics of microorganisms and vegetation. The objective of this study was to investigate the spatial and temporal variability of C and N isotope ratios as indicators of the cycling of these elements in a cerrado sensu stricto area, within a protected area in a State Park in the state of São Paulo, Brazil. The foliar δ13C and δ15N values varied from -33.6 to -24.4 ‰ and -2.5 to 4.5 ‰, respectively. The δ13C values showed a consistent relationship with canopy height, revealing the importance of structure of the canopy over the C isotopic signature of the vegetation. Carbon isotopic variations associated with the length of the dry season indicated the importance of recent fixed C to the integrated isotopic signature of the leaf organic C. The studied Cerrado species showed a depleted foliar δ15N, but a wide range of foliar Nitrogen with no difference among canopy heights. However, seasonal variability was observed, with foliar δ15N values being higher in the transition period between dry and rainy seasons. The variation of the foliar C and N isotope ratios presented here was consistent with highly diverse vegetation with high energy available but low availability of water and N.

Validation of the Deardorff model for estimating energy balance components for a sugarcane crop

The quantification of the available energy in the environment is important because it determines photosynthesis, evapotranspiration and, therefore, the final yield of crops. Instruments for measuring the energy balance are costly and indirect estimation alternatives are desirable. This study assessed the Deardorff's model performance during a cycle of a sugarcane crop in Piracicaba, State of São Paulo, Brazil, in comparison to the aerodynamic method. This mechanistic model simulates the energy fluxes (sensible, latent heat and net radiation) at three levels (atmosphere, canopy and soil) using only air temperature, relative humidity and wind speed measured at a reference level above the canopy, crop leaf area index, and some pre-calibrated parameters (canopy albedo, soil emissivity, atmospheric transmissivity and hydrological characteristics of the soil). The analysis was made for different time scales, insolation conditions and seasons (spring, summer and autumn). Analyzing all data of 15 minute intervals, the model presented good performance for net radiation simulation in different insolations and seasons. The latent heat flux in the atmosphere and the sensible heat flux in the atmosphere did not present differences in comparison to data from the aerodynamic method during the autumn. The sensible heat flux in the soil was poorly simulated by the model due to the poor performance of the soil water balance method. The Deardorff's model improved in general the flux simulations in comparison to the aerodynamic method when more insolation was available in the environment.

Ontogenesis of stomata in Velloziaceae: paracytic versus tetracytic?

In Velloziaceae, the number of subsidiary cells has been used to characterize species and support groups. Nevertheless, the homology of the stomatal types have not been scrutinized. Stomatal ontogenesis of Vellozia epidendroides and V. plicata, assigned to have tetracytic stomata, and of V. glauca and Barbacenia riparia, assigned to have paracytic stomata, were investigated. In the four species studied, stomata followed perigenic development. Subsidiary cells arise from oblique divisions of neighbouring cells of the guard mother cell (GMC). These cells are elongated and parallel to the longer axis of the stoma. Polar cells show wide variation, following the shape and size of the epidermal cells in the vicinity. Hence, these cells cannot be called subsidiary cells. This wide variation is due to a much higher density of stomata in some regions of the leaf blade. This distribution of stomata forces the development of short polar cells, leading to an apparently tetracytic stomata. In regions of low concentration of stomata, higher spatial availability between the GMCs allows the elongation of polar cells, leading to evident paracytic stomata. Therefore, the four studied species are considered braquiparacytic, questioning the classification of stomata into tetracytic and paracytic in Velloziaceae.

Allometric models for estimating the phytomass of a secondary Atlantic Forest area of southeastern Brazil

The purpose of this study was to develop and validate equations to estimate the aboveground phytomass of a 30 years old plot of Atlantic Forest. In two plots of 100 m², a total of 82 trees were cut down at ground level. For each tree, height and diameter were measured. Leaves and woody material were separated in order to determine their fresh weights in field conditions. Samples of each fraction were oven dried at 80 °C to constant weight to determine their dry weight. Tree data were divided into two random samples. One sample was used for the development of the regression equations, and the other for validation. The models were developed using single linear regression analysis, where the dependent variable was the dry mass, and the independent variables were height (h), diameter (d) and d²h. The validation was carried out using Pearson correlation coefficient, paired t-Student test and standard error of estimation. The best equations to estimate aboveground phytomass were: lnDW = -3.068+2.522lnd (r² = 0.91; s y/x = 0.67) and lnDW = -3.676+0.951ln d²h (r² = 0.94; s y/x = 0.56).

Modelos preditores da fitomassa aérea da Floresta Baixa de Restinga

Este estudo teve como objetivo desenvolver modelos preditores de fitomassa epigéa da vegetação arbórea da Floresta Baixa de Restinga. Foram selecionadas 102 árvores de 29 espécies ocorrentes na área de estudo e 102 indivíduos de jerivá (Syagrus romanzoffiana (Cham.) Glassman), distribuídos proporcionalmente entre as classes de diâmetro da vegetação arbórea. As árvores foram cortadas, ao nível do solo e foram medidos a altura total e o diâmetro à altura do peito (DAP) de cada árvore. As folhas foram separadas do lenho e a massa fresca da porção lenhosa e foliar medidas separadamente. Amostras de cada fração foram secas a 70 °C, até peso constante, para determinação da massa seca das árvores. Os modelos foram desenvolvidos através de análise de regressão linear, sendo a variável dependente a massa seca (MS) das árvores e as variáveis independentes a altura (h), o diâmetro a altura do peito (d) e as relações d² h e d² h multiplicada pela densidade da madeira (ρ d² h). Os modelos desenvolvidos indicam que o diâmetro explica grande parte da variabilidade da fitomassa das árvores da restinga e a altura é a variável explanatória da equação específica para o jerivá. Os modelos selecionados foram: ln MS (kg) = -1,352 + 2,009 ln d (R² = 0,96; s yx = 0,34) para a comunidade vegetal sem jerivá, ln MS (kg) = -2,052 + 0,801 ln d² h (R² = 0,94; s yx = 0,38) para a comunidade incluindo o jerivá, e ln MS (kg) = -0,884 + 2,40 ln h (R² = 0,92; s yx = 0,49) para o jerivá.

A casa e a roça: socioeconomia, demografia e agricultura em populações quilombolas do Vale do Ribeira, São Paulo, Brasil

Este estudo tem como objetivos caracterizar o perfil demográfico e socioeconômico de nove comunidades remanescentes de quilombos no vale do Ribeira, estado de São Paulo, e identificar os principais fatores responsáveis pelas mudanças recentes nos seus padrões de subsistência. Desde a formação das primeiras aglomerações de escravos libertos e foragidos no século XVIII, as relações estabelecidas entre estas populações com as cidades próximas e com o mercado regional têm vivenciado momentos de retração e de expansão, adaptando-se e ajustando-se a novas mudanças políticas e socioeconômicas. Nas últimas cinco décadas, o impacto de fatores externos na aceleração das mudanças nos padrões de subsistência locais parece ter tido um aumento significativo. Os resultados mostram que as restrições impostas pela legislação ambiental, os conflitos de terra, a construção de uma rodovia na região, a crescente inserção no mercado regional e a atuação de órgãos governamentais e não-governamentais de desenvolvimento são os principais fatores responsáveis pelas mudanças observadas no sistema agrícola de corte e queima e, conseqüentemente, na organização socioeconômica destas populações.

Impact on human health of particulate matter emitted from burnings in the Brazilian Amazon region

OBJECTIVE: To analyze the impact on human health of exposure to particulate matter emitted from burnings in the Brazilian Amazon region. METHODS: This was an ecological study using an environmental exposure indicator presented as the percentage of annual hours (AH%) of PM2.5 above 80 μg/m3. The outcome variables were the rates of hospitalization due to respiratory disease among children, the elderly and the intermediate age group, and due to childbirth. Data were obtained from the National Space Research Institute and the Ministry of Health for all of the microregions of the Brazilian Amazon region, for the years 2004 and 2005. Multiple regression models for the outcome variables in relation to the predictive variable AH% of PM2.5 above 80 μg/m3 were analyzed. The Human Development Index (HDI) and mean number of complete blood counts per 100 inhabitants in the Brazilian Amazon region were the control variables in the regression analyses. RESULTS: The association of the exposure indicator (AH%) was higher for the elderly than for other age groups (β = 0.10). For each 1% increase in the exposure indicator there was an increase of 8% in child hospitalization, 10% in hospitalization of the elderly, and 5% for the intermediate age group, even after controlling for HDI and mean number of complete blood counts. No association was found between the AH% and hospitalization due to childbirth. CONCLUSIONS: The indicator of atmospheric pollution showed an association with occurrences of respiratory diseases in the Brazilian Amazon region, especially in the more vulnerable age groups. This indicator may be used to assess the effects of forest burning on human health.

Air pollution and hospital admissions for respiratory diseases in the subequatorial Amazon: a time series approach

The objective of the study is to evaluate the effect of the daily variation in concentrations of fine particulate matter (diameter less than 2.5µm - PM2.5) resulting from the burning of biomass on the daily number of hospitalizations of children and elderly people for respiratory diseases, in Alta Floresta and Tangará da Serra in the Brazilian Amazon in 2005. This is an ecological time series study that uses data on daily number of hospitalizations of children and the elderly for respiratory diseases, and estimated concentration of PM2.5. In Alta Floresta, the percentage increases in the relative risk (%RR) of hospitalization for respiratory diseases in children were significant for the whole year and for the dry season with 3-4 day lags. In the dry season these measurements reach 6% (95%CI: 1.4-10.8). The associations were sig-nificant for moving averages of 3-5 days. The %RR for the elderly was significant for the current day of the drought, with a 6.8% increase (95%CI: 0.5-13.5) for each additional 10µg/m3 of PM2.5. No as-sociations were verified for Tangara da Serra. The PM2.5 from the burning of biomass increased hospitalizations for respiratory diseases in children and the elderly.

Quantification and source identification of atmospheric particulate polycyclic aromatic hydrocarbons and their dry deposition fluxes at three sites in Salvador Basin, Brazil, impacted by mobile and stationary sources

The present work has aimed to determine the 16 US EPA priority PAH atmospheric particulate matter levels present in three sites around Salvador, Bahia: (i) Lapa bus station, strongly impacted by heavy-duty diesel vehicles; (ii) Aratu harbor, impacted by an intense movement of goods, and (iii) Bananeira village on Maré Island, a non vehicle-influenced site with activities such as handcraft work and fisheries. Results indicated that BbF (0.130-6.85 ng m-3) is the PAH with highest concentration in samples from Aratu harbor and Bananeira and CRY (0.075-6.85 ng m-3) presented higher concentrations at Lapa station. PAH sources from studied sites were mainly of anthropogenic origin such as gasoline-fueled light-duty vehicles and diesel-fueled heavy-duty vehicles, discharges in the port, diesel burning from ships, dust ressuspension, indoor soot from cooking, and coal and wood combustion for energy production.

Massa das sementes de Tecoma stans L. Juss. ex Kunth (Bignoniaceae): efeitos na emergência e desenvolvimento de suas plântulas no sol e na sombra

The aim of this study was to evaluate the effect of Tecoma stans L. Juss. ex Kunth seeds mass on initial emergence, growth and, seedling development under different light conditions. The seeds were separated in four mass classes and sowed in four replicates of 24 seeds for each class, under full sun and canopy shade. Under sun environment was observed a greater percentage of emergence. Heavy seeds presented the greater percentage of emergence under both environments, but a greater rate was observed under canopy shade. One month after the start of experiments, the seedlings at the shade environment presented 100% of mortality. The growth and development seedlings under full sun were noticed for five months. In this period, only in the first three months was possible to observe the effects of Tecoma stans seeds mass on capacity of seedlings to acquire dry mass. The seedlings biomass partitions were similar among the tested mass class. The seedlings of smaller mass tended to a high specific leaf area in relation to the seedlings from large seeds, mainly in the first three months, resulting in a great acquisition of dry mass by these seedlings. In the fourth month, the specific leaf area did not present any tendency. Because the biggest seeds to give rise seedlings with best initial development than smallest seeds can be considered as species reproductive strategy. To produce seeds of different sizes also can be considered as way of species to spread in many microhabitats.

Queimadas de cana-de-açúcar: Avaliação de efeitos na qualidade do ar e na saúde respiratória de crianças

Pesquisa em Espírito Santo do Turvo (SP) analisou poluição atmosférica causada por queima de cana-de-açúcar e saúde respiratória de crianças. Realizaram-se medições de PM10, PTS e NO2, durante safra, em 2004 e 2005, em pátio de escola, e aplicou-se questionário para avaliar morbidade respiratória referida dos alunos. No município, há cultivo de cana, queimada no pré-corte e usina próxima à área urbana. Resultados dos questionários foram comparados àqueles obtidos em Juquitiba (SP) previamente. As medições de poluentes, realizadas em dias em que havia queima de cana, estiveram abaixo dos padrões de qualidade do ar. Entretanto, foram indicadas altas prevalências de sintomas e doenças respiratórias.

Queimadas nos canaviais e perspectivas dos cortadores de cana-de-açúcar em Macatuba, São Paulo

A lei nº 11.241/2002 do estado de São Paulo proíbe a queima de cana-de-açúcar pré-colheita devido ao alto impacto que a fumaça desse processo causa na saúde coletiva e no meio ambiente. De modo gradativo, a previsão inicial era de que a proibição fosse efetiva em 2031. Posteriormente, acordo entre governo do Estado e União da Indústria de Cana-de-açúcar (Unica), estabeleceu redução do prazo para 2017. A cana-de-açúcar, quando não queimada, exige muito mais esforço dos cortadores, diminuindo a produtividade do corte manual em comparação às máquinas colheitadeiras. A ausência das queimadas traz benefícios à saúde e ao meio ambiente, no entanto, pouco ainda se sabe a respeito das consequências da mecanização para a mão de obra rural nos canaviais. Este artigo busca analisar esse quadro de incerteza sobre o que ocorrerá do ponto de vista dos cortadores de cana e o reconhecimento das consequências da lei em suas vidas. Durante a safra de cana de 2006, foram aplicados questionários a 40 cortadores de cana, de diferentes idades e gênero, no bairro Jardim América, em Macatuba-SP, em suas casas ou na rua. Perguntas qualitativas e quantitativas que abordavam temas socioeconômicos, de saúde, reconhecimento da lei e perspectivas de trabalho. Os entrevistados apresentaram um dilema entre o ar limpo e a perspectiva de trabalho. Muitos se apresentaram indecisos e sem incentivos a trabalhar em outros setores, apesar de grande parte gostar do local onde vive e se interessar por continuar a trabalhar na agricultura