77 resultados para Bio-economic index
Resumo:
BACKGROUND: Defoliation by Anticarsia gemmatalis (Hubner), Pseudoplusia includens (Walker), Spodoptera eridania (Cramer), S. cosmioides (Walker) and S. frugiperda (JE Smith) (Lepidoptera: Noctuidae) was evaluated in four soybean genotypes. A multiple-species economic threshold (ET), based upon the species` feeding capacity, is proposed with the aim of improving growers` management decisions on when to initiate control measures for the species complex. RESULTS: Consumption by A. gemmatalis, S. cosmioides or S. eridania on different genotypes was similar. The highest consumption of P. includens was 92.7 cm(2) on Codetec 219RR; that of S. frugiperda was 118 cm(2) on Codetec 219RR and 115.1 cm(2) on MSoy 8787RR. The insect injury equivalent for S. cosmoides, calculated on the basis of insect consumption, was double the standard consumption by A. gemmatalis, and statistically different from the other species tested, which were similar to each other. CONCLUSIONS: As S. cosmioides always defoliated nearly twice the leaf area of the other species, the injury equivalent would be 2 for this lepidopteran species and 1 for the other species. The recommended multiple-species ET to trigger the beginning of insect control would then be 20 insect equivalents per linear metre. (C) 2010 Society of Chemical Industry
Resumo:
The objective of this work was to evaluate the economic feasibility of cowpea irrigation in Piaui State Brazil. Water balances were carried out on a daily basis using the Thornthwaite and Mather (1955) method, for 165 sites, considering twelve sowings dates and available water capacity in the soil of 20, 40 and 60 mm. The net revenues were estimated with a probability of occurrence of 75%, later being spatialized to Piaui State. Cowpea irrigation was shown to economically viable for all sowing dates, irrespective of the available water capacity. Net revenues varied among several regions of the State, in function of the sowing date and available water capacity in the soil. Considering a planning strategy for Piaui State, sowing on February, I was shown to be most favorable, because it enabled higher net revenue values, covering larger areas of the State.
Resumo:
The aim of this work was to study the diversity of the fauna of plant-parasitic nematodes in preserved areas of the Amazon forest, Mato Grosso state (MT), and to assess the effect of agricultural land use on plant-parasitic nematode communities. Soil and root samples were collected in each location in the late spring during the rainy season of 2005, in two areas of primary vegetation in Nova Maringa (Northwest) and Guaranta do Norte (North) and two adjacent areas planted with teak trees (Tectona grandis) and pasture (Brachiaria brizantha). Four-teen taxa of plant-parasitic nematodes were identified at species level: Discocriconemella degrissei, D. limitanea, Dolichodorus minor, Helicotylenchus erythrinae, H. pseudorobustus, Meloidogyne exigua, M javanica, Mesocriconema ornata, Paratrichodorus minor, Pratylenchus loosi, P zeae, Rotylenchus caudaphasmidius, Xiphinema ensiculiferum and X luci (for the first report of this in Brazil) and five at genus level (Atalodera sp., Hemicriconemoides sp., Meloidogyne sp., Paratylenchus sp., and Trophotylenchulus sp). These taxa, mainly those from primary vegetation, belong to families with different parasitic behavior, probably due to great plant diversity in the Amazon forest. Comparison between the two preserved areas revealed low index of similarity, as a consequence of the endemic flora in the Amazon forest, and no similarity was observed between preserved native vegetation and adjacent cultivated areas, demonstrating the high influence of agricultural activity on the plant-parasitic nematode communities. There is evidence of recent introduction of plant-parasitic nematodes in these cultivated areas; therefore measures should be taken to prevent the loss of economic sustainability in Amazonian soils. Keywords: abundance, Amazonia, diversity, Brachiaria brizantha, plant-parasitic nematode fauna, Tectona grandis.
Resumo:
Understanding resource capture can help design appropriate species combinations, planting designs and management. Leaf area index (LAI) and its longevity are the most important factors defining dry matter production and thus growth and productivity. The ecophysiological modifications and yield of rubber (Hevea spp.) in an agroforestry system (AFS) with beans (Phaseolus vulgaris L.) were studied. The experiment was established in Southeast-Brazil, with three rubber cultivars: IAN 3087, RRIM 600 and RRIM 527. The AFS comprised double rows of rubber trees along with beans sown in autumn and winter seasons in 1999. There was about 50% higher rubber yield per tree in the AFS than the rubber monoculture. Trees within the AFS responded to higher solar radiation availability with higher LAI and total foliage area, allowing its greater interception. All three cultivars had higher LAI in the AFS than monoculture, reaching maximum values in the AFS between April and May of 3.17 for RRIM 527; 2.83 for RRIM 600 and 2.28 for IAN 3087. The maximum LAI values for monocrop rubber trees were: 2.65, 2.62 and 1.99, respectively, for each cultivar. Rubber production and LAI were positively correlated in both the AFS and monoculture but leaf fall of rubber trees in the AFS was delayed and total phytomass was larger. It is suggested that trees in the AFS were under exploited and could yield more without compromising their life cycle if the tapping system was intensified. This shows how knowledge of LAI can be used to manage tapping intensity in the field, leading to higher rubber yield.
Resumo:
Our objective was to develop a methodology to predict soil fertility using visible near-infrared (vis-NIR) diffuse reflectance spectra and terrain attributes derived from a digital elevation model (DEM). Specifically, our aims were to: (i) assemble a minimum data set to develop a soil fertility index for sugarcane (Sarcharum officinarum L.) (SFI-SC) for biofuel production in tropical soils; (ii) construct a model to predict the SFI-SC using soil vis-NIR spectra and terrain attributes; and (iii) produce a soil fertility map for our study area and assess it by comparing it with a green vegetation index (GVI). The study area was 185 ha located in sao Paulo State, Brazil. In total, 184 soil samples were collected and analyzed for a range of soil chemical and physical properties. Their vis-NIR spectra were collected from 400 to 2500 nm. The Shuttle Radar Topographic Mission 3-arcsec (90-m resolution) DEM of the area was used to derive 17 terrain attributes. A minimum data set of soil properties was selected to develop the SFI-SC. The SFI-SC consisted of three classes: Class 1, the highly fertile soils; Class 2, the fertile soils; and Class 3, the least fertile soils. It was derived heuristically with conditionals and using expert knowledge. The index was modeled with the spectra and terrain data using cross-validated decision trees. The cross-validation of the model correctly predicted Class 1 in 75% of cases, Class 2 in 61%, and Class 3 in 65%. A fertility map was derived for the study area and compared with a map of the GVI. Our approach offers a methodology that incorporates expert knowledge to derive the SFI-SC and uses a versatile spectro-spatial methodology that may be implemented for rapid and accurate determination of soil fertility and better exploration of areas suitable for production.
Resumo:
Impaired immune system by environmental stressors can lead fishes to be more susceptible to diseases that limit the economic development of aquaculture systems. This study was set out to determine the effect of six levels of mannan oligosaccharides (MOS; ActiveMOS((R)); Biorigin, Lencois Paulista, Sao Paulo, Brazil) on the performance index and hematology of Nile tilapia, Oreochromis niloticus juveniles. Fish (13.62 g) were randomly distributed into 18 plastic aquaria (300 L; 20 fishes per aquarium) and fed during 45 d with a commercial diet supplemented with 0, 0.2, 0.4, 0.6, 0.8, and 1% dietary MOS, in a totally randomized design trial (n = 3); biometrical and hematological data were collected and analyzed. There were no significant differences in hematological parameters between fish fed control and MOS supplementation diets, and daily feed consumption (FC) decreased (P < 0.05) with increasing levels of dietary MOS. Dietary MOS did not increase leukocyte count and presented negative effects on FC of Nile tilapia. At 0.4% MOS supplementation, the individual weight gain was higher in absolute values but not different (P > 0.05) compared to control diet.
Resumo:
The leaf area index (LAI) of fast-growing Eucalyptus plantations is highly dynamic both seasonally and interannually, and is spatially variable depending on pedo-climatic conditions. LAI is very important in determining the carbon and water balance of a stand, but is difficult to measure during a complete stand rotation and at large scales. Remote-sensing methods allowing the retrieval of LAI time series with accuracy and precision are therefore necessary. Here, we tested two methods for LAI estimation from MODIS 250m resolution red and near-infrared (NIR) reflectance time series. The first method involved the inversion of a coupled model of leaf reflectance and transmittance (PROSPECT4), soil reflectance (SOILSPECT) and canopy radiative transfer (4SAIL2). Model parameters other than the LAI were either fixed to measured constant values, or allowed to vary seasonally and/or with stand age according to trends observed in field measurements. The LAI was assumed to vary throughout the rotation following a series of alternately increasing and decreasing sigmoid curves. The parameters of each sigmoid curve that allowed the best fit of simulated canopy reflectance to MODIS red and NIR reflectance data were obtained by minimization techniques. The second method was based on a linear relationship between the LAI and values of the GEneralized Soil Adjusted Vegetation Index (GESAVI), which was calibrated using destructive LAI measurements made at two seasons, on Eucalyptus stands of different ages and productivity levels. The ability of each approach to reproduce field-measured LAI values was assessed, and uncertainty on results and parameter sensitivities were examined. Both methods offered a good fit between measured and estimated LAI (R(2) = 0.80 and R(2) = 0.62 for model inversion and GESAVI-based methods, respectively), but the GESAVI-based method overestimated the LAI at young ages. (C) 2010 Elsevier Inc. All rights reserved.
Resumo:
By allowing the estimation of forest structural and biophysical characteristics at different temporal and spatial scales, remote sensing may contribute to our understanding and monitoring of planted forests. Here, we studied 9-year time-series of the Normalized Difference Vegetation Index (NDVI) from the Moderate Resolution Imaging Spectroradiometer (MODIS) on a network of 16 stands in fast-growing Eucalyptus plantations in Sao Paulo State, Brazil. We aimed to examine the relationships between NDVI time-series spanning entire rotations and stand structural characteristics (volume, dominant height, mean annual increment) in these simple forest ecosystems. Our second objective was to examine spatial and temporal variations of light use efficiency for wood production, by comparing time-series of Absorbed Photosynthetically Active Radiation (APAR) with inventory data. Relationships were calibrated between the NDVI and the fractions of intercepted diffuse and direct radiation, using hemispherical photographs taken on the studied stands at two seasons. APAR was calculated from the NDVI time-series using these relationships. Stem volume and dominant height were strongly correlated with summed NDVI values between planting date and inventory date. Stand productivity was correlated with mean NDVI values. APAR during the first 2 years of growth was variable between stands and was well correlated with stem wood production (r(2) = 0.78). In contrast, APAR during the following years was less variable and not significantly correlated with stem biomass increments. Production of wood per unit of absorbed light varied with stand age and with site index. In our study, a better site index was accompanied both by increased APAR during the first 2 years of growth and by higher light use efficiency for stem wood production during the whole rotation. Implications for simple process-based modelling are discussed. (C) 2009 Elsevier B.V. All rights reserved.
Resumo:
Governments are promoting biofuels and the resulting changes in land use and crop reallocation to biofuels production have raised concerns about impacts on environment and food security. The promotion of biofuels has also been questioned based on suggested marginal contribution to greenhouse gas emissions reduction, partly due to induced land use change causing greenhouse gas emissions. This study reports how the expansion of sugarcane in Brazil during 1996-2006 affected indicators for environment, land use and economy. The results indicate that sugarcane expansion did not in general contribute to direct deforestation in the traditional agricultural region where most of the expansion took place. The amount of forests on farmland in this area is below the minimum stated in law and the situation did not change over the studied period. Sugarcane expansion resulted in a significant reduction of pastures and cattle heads and higher economic growth than in neighboring areas. It could not be established to what extent the discontinuation of cattle production induced expansion of pastures in other areas, possibly leading to indirect deforestation. However, the results indicate that a possible migration of the cattle production reached further than the neighboring of expansion regions. Occurring at much smaller rates, expansion of sugarcane in regions such as the Amazon and the Northeast region was related to direct deforestation and competition with food crops, and appear not to have induced economic growth. These regions are not expected to experience substantial increases of sugarcane in the near future, but mitigating measures are warranted.
Resumo:
Researchers working with thermal comfort have been using enthalpy to measure thermal energy inside rural facilities, establishing indicator values for many situations of thermal comfort and heat stress. This variable turned out to be helpful in analyzing thermal exchange in livestock systems. The animals are exposed to an environment which is decisive for the thermoregulatory process, and, consequently, the reactions reflect states of thermal comfort or heat stress, the last being responsable for problems of sanity, behavior and productivity. There are researchers using enthalpy as a qualitative indicator of thermal environment of livestock such as poultry, cattle and hogs in tropical regions. This preliminary work intends to check different enthalpy equations using information from classical thermodynamics, and proposes a direct equation as thermal comfort index for livestock systems.
Resumo:
Background: The pathophysiology of spontaneous abortion is complex and may involve the interaction of genetic and environmental factors. We evaluated the predictors of spontaneous abortion in Brazilian pregnant women. The effects of age, gestational age. body mass index (BMI), cigarette smoking, alcohol ingestion, use of multivitamins and concentrations of vitamins (folate, cobalamin and vitamin 136) and vitamin-dependent metabolites were analyzed. Methods: Study population included 100 healthy women that attended pre-natal care in 2 health centers of Sao Paulo, Brazil, and in whom pregnancy outcome was known. Folate and cobalamin status was measured in blood specimens collected between 4 and 16 weeks. The genotypes for 8 gene polymorphisms were evaluated by PCR-RFLP. Results: Eighty-eight women had normal pregnancy outcome (Group 1), while 12 experienced a miscarriage after blood collection (Group 2). Increased methylmalonic acid (MMA) concentrations were found in Group 2 (median [25th-75th percentile]=274 [149-425] nmol/l) relative to Group 1 (138 [98-185]) (P<0.01). No differences between the groups were observed for serum cobalamin, serum or red cell folate, and serum total homocysteine or allele frequencies for 8 polymorphisms. In a conditional logistic regression analysis including age, gestational age, serum creatinine, MMA, cystathionine, body mass index (BMI), cigarette smoking, alcohol ingestion and use of multivitamins the risk of abortion was significantly associated with MMA (OR [95% CI] = 3.80 [1.36, 10.62] per quartile increase in MMA), BMI (OR [95% CI] = 5.49 [1.29,23.39] per quartile) and gestational age (OR [95% CI] = 0.10 [0.01, 0.77] per increase of interval in gestational age). Conclusions: Increased serum MMA and BMI concentrations are associated with spontaneous abortion in Brazilian women. (C) 2009 Elsevier B.V. All rights reserved.
Resumo:
The purposes of this work were: (1) to comparatively evaluate the effects of hypromellose viscosity grade and content on ketoprofen release from matrix tablets, using Bio-Dis and the paddle apparatuses, (2) to investigate the influence of the pH of the dissolution medium on drug release. Furthermore, since direct compression had not shown to be appropriate to obtain the matrices under study, it was also an objective (3) to evaluate the impact of granulation on drug release process. Six formulations of ketoprofen matrix tablets were obtained by compression, with or without previous granulation, varying the content and viscosity grade of hypromellose. Dissolution tests were carried out at a fixed pH, in each experiment, with the paddle method (pH 4.5, 6.0, 6.8, or 7.2), while a pH gradient was used in Bio-Dis (pH 1.2 to 7.2). The higher the hypromellose viscosity grade and content were, the lower the amount of ketoprofen released was in both apparatuses, the content effect being more expressive. Drug dissolution enhanced with the increase of the pH of the medium due to its pH-dependent solubility. Granulation caused an increase in drug dissolution and modified the mechanism of the release process.
Resumo:
In this study, 20 Brazilian public schools have been assessed regarding good manufacturing practices and standard sanitation operating procedures implementation. We used a checklist comprised of 10 parts ( facilities and installations, water supply, equipments and tools, pest control, waste management, personal hygiene, sanitation, storage, documentation, and training), making a total of 69 questions. The implementing modification cost to the found nonconformities was also determined so that it could work with technical data as a based decision-making prioritization. The average nonconformity percentage at schools concerning to prerequisite program was 36%, from which 66% of them own inadequate installations, 65% waste management, 44% regarding documentation, and 35% water supply and sanitation. The initial estimated cost for changing has been U.S.$24,438 and monthly investments of 1.55% on the currently needed invested values. This would result in U.S.$0.015 increase on each served meal cost over the investment replacement within a year. Thus, we have concluded that such modifications are economically feasible and will be considered on technical requirements when prerequisite program implementation priorities are established.
Resumo:
This study is an integral part of a research project which seeks the establishment of protocols for the production of standardized herbal dried extracts emphasizing the spouted bed drying. This thesis was conducted at faculty of Pharmaceutical Science of Ribeiro Preto/University of So Paulo, Brazil, under supervision of Prof. Dr. Wanderley Pereira Oliveira*, defended on September 28, 2007.
Resumo:
This paper contributes to the literature on balance-of-payments constrained growth by investigating how structural change identified with changes in the sectoral composition of exports and imports affects the external constraint We test both the original and a multisectoral version of Thirlwall`s law for a sample of Latin American and Asian countries The original Thirlwall s law is found to hold for all sample countries except South Korea, whereas the multisectoral analogue holds for all of them As the sectoral composition of exports and imports is found to matter for growth we analyze the evolution of each country`s weighted trade income elasticities