994 resultados para Brazil and U.S.A


Relevância:

90.00% 90.00%

Publicador:

Resumo:

ABSTRACT The external morphology of immature stages of Zaretis strigosus (Gmelin, [1790]) and Siderone galanthis catarina Dottax and Pierre, 2009 comb. nov. from southern Brazil are described. Additionally, morphology of the adults and sequences of the mitochondrial gene cytochrome oxidase, subunit I, were analyzed in order to evaluate the taxonomy of Siderone galanthis Hübner, [1823]. Immatures were collected on Casearia sylvestris (Salicaceae) in Curitiba, Paraná, and Balneário Barra do Sul, Santa Catarina, Brazil, and reared at the laboratory. Morphological descriptions and illustrations are provided, based on observations through stereoscopic and optic microscopes attached to camera lucida; results are compared and discussed and immature stages of some other species of Charaxinae. The results indicates that the morphology of the immature stages of the studied species differ greatly from other Anaeini, representing a distinct lineage of leafwings butterflies. Morphology and molecular evidence indicate that S. nemesis mexicana Dottax and Pierre, 2009 and S. nemesis catarina Dottax and Pierre, 2009 are conspecific with S. galanthis (Cramer, 1775); additionally, S. thebais C. Felder and R. Felder 1862, S. nemesis var. confluens Staudinger, 1887, S. nemesis f. leonora Bargmann, 1928 and S. nemesis f. exacta Bargmann, 1929 are synonymized with S. galanthis galanthis (Cramer, 1775).

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Soybean is a major grain crop in Brazil, and yields can be considerably improved by inoculation with selected Bradyrhizobium strains. However, the incompatibility between inoculation and seed treatments with fungicides and micronutrients represents a major barrier to the achievement of high rates of biological N2 fixation. Inoculation practices that can alleviate the negative effects of agrochemicals must therefore be found and in-furrow inoculation seems to be an attractive alternative. This study reports the results of seven field experiments conducted in three growing seasons in Brazil; three in soils previously cropped with inoculated soybean (> 10(4) cells g-1 of soil of Bradyrhizobium), and four in areas where the crop was sown for the first time (< 10² cells g-1 of soil of Bradyrhizobium). The compatibility with fungicides and micronutrients was compared in seeds inoculated with peat or liquid inoculants, or treated with different doses of liquid inoculant in-furrow. In areas with established Bradyrhizobium populations, seed-applied agrochemicals did generally not affect nodulation, but also did not increase yields, while inoculation always increased N grain accumulation or yield, and N fertilizer decreased both nodulation and yield. Where soybean was sown for the first time, the seed treatment with agrochemicals affected nodulation when applied together with peat or liquid inoculant. In-furrow inoculation alleviated the effects of seed treatment with agrochemicals; the best performance was achieved with high Bradyrhizobium cell concentrations, with up to 2.5 million cells seed-1.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

The occurrence of Umbric Ferralsols with thick umbric epipedons (> 100 cm thickness) in humid Tropical and Subtropical areas is a paradox since the processes of organic matter decomposition in these environments are very efficient. Nevertheless, this soil type has been reported in areas in the Southeast and South of Brazil, and at some places in the Northeast. Aspects of the genesis and paleoenvironmental significance of these Ferralsols still need a better understanding. The processes that made the umbric horizons so thick and dark and contributed to the preservation of organic carbon (OC) at considerable depths in these soils are of special interest. In this study, eight Ferralsols with a thick umbric horizon (UF) under different vegetation types were sampled (tropical rain forest, tropical seasonal forest and savanna woodland) and their macromorphological, physical, chemical and mineralogical properties studied to detect soil characteristics that could explain the preservation of high carbon amounts at considerable depths. The studied UF are clayey to very clayey, strongly acidic, dystrophic, and Al-saturated and charcoal fragments are often scattered in the soil matrix. Kaolinites are the main clay minerals in the A and B horizons, followed by abundant gibbsite and hydroxyl-interlayered vermiculite. The latter was only found in UFs derived from basalt rock in the South of the country. Total carbon (TC) ranged from 5 to 101 g kg-1 in the umbric epipedon. Dichromate-oxidizable organic carbon represented nearly 75 % of TC in the thick A horizons, while non-oxidizable C, which includes recalcitrant C (e.g., charcoal), contributed to the remaining 25 % of TC. Carbon contents were not related to most of the inorganic soil variables studied, except for oxalate-extractable Al, which individually explained 69 % (P < 0.001) of the variability of TC in the umbric epipedon. Clay content was not suited as predictor of TC or of the other studied C forms. Bulk density, exchangeable Al3+, Al saturation, ECEC and other parameters obtained by selective extraction were not suitable as predictors of TC and other C forms. Interactions between organic matter and poorly crystalline minerals, as indicated by oxalate-extractable Al, appear to be one of the possible organic matter protection mechanisms of these soils.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Soil organic matter (SOM) plays an important role in carbon (C) cycle and soil quality. Considering the complexity of factors that control SOM cycling and the long time it usually takes to observe changes in SOM stocks, modeling constitutes a very important tool to understand SOM cycling in forest soils. The following hypotheses were tested: (i) soil organic carbon (SOC) stocks would be higher after several rotations of eucalyptus than in low-productivity pastures; (ii) SOC values simulated by the Century model would describe the data better than the mean of observations. So, the aims of the current study were: (i) to evaluate the SOM dynamics using the Century model to simulate the changes of C stocks for two eucalyptus chronosequences in the Rio Doce Valley, Minas Gerais State, Brazil; and (ii) to compare the C stocks simulated by Century with the C stocks measured in soils of different Orders and regions of the Rio Doce Valley growing eucalyptus. In Belo Oriente (BO), short-rotation eucalyptus plantations had been cultivated for 4.0; 13.0, 22.0, 32.0 and 34.0 years, at a lower elevation and in a warmer climate, while in Virginópolis (VG), these time periods were 8.0, 19.0 and 33.0 years, at a higher elevation and in a milder climate. Soil samples were collected from the 0-20 cm layer to estimate C stocks. Results indicate that the C stocks simulated by the Century model decreased after 37 years of poorly managed pastures in areas previously covered by native forest in the regions of BO and VG. The substitution of poorly managed pastures by eucalyptus in the early 1970´s led to an average increase of C of 0.28 and 0.42 t ha-1 year-1 in BO and VG, respectively. The measured C stocks under eucalyptus in distinct soil Orders and independent regions with variable edapho-climate conditions were not far from the values estimated by the Century model (root mean square error - RMSE = 20.9; model efficiency - EF = 0.29) despite the opposite result obtained with the statistical procedure to test the identity of analytical methods. Only for lower soil C stocks, the model over-estimated the C stock in the 0-20 cm layer. Thus, the Century model is highly promising to detect changes in C stocks in distinct soil orders under eucalyptus, as well as to indicate the impact of harvest residue management on SOM in future rotations.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

The soil penetration resistance is an important indicator of soil compaction and is strongly influenced by soil water content. The objective of this study was to develop mathematical models to normalize soil penetration resistance (SPR), using a reference value of gravimetric soil water content (U). For this purpose, SPR was determined with an impact penetrometer, in an experiment on a Dystroferric Red Latossol (Rhodic Eutrudox), at six levels of soil compaction, induced by mechanical chiseling and additional compaction by the traffic of a harvester (four, eight, 10, and 20 passes); in addition to a control treatment under no-tillage, without chiseling or additional compaction. To broaden the range of U values, SPR was evaluated in different periods. Undisturbed soil cores were sampled to quantify the soil bulk density (BD). Pedotransfer functions were generated correlating the values of U and BD to the SPR values. By these functions, the SPR was adequately corrected for all U and BD data ranges. The method requires only SPR and U as input variables in the models. However, different pedofunctions are needed according to the soil layer evaluated. After adjusting the pedotransfer functions, the differences in the soil compaction levels among the treatments, previously masked by variations of U, became detectable.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Phosphorus (P) applications to vineyards can cause P accumulation in the soil and maximize pollution risks. This study was carried out to quantify the accumulation of P fractions in sandy soils of vineyards in southern Brazil. Soil samples (layers 0-5, 6-10 and 11-20 cm) were collected from a native grassland area and two vineyards, after 14 years (vineyard 1) and 30 years (vineyard 2) of cultivation, in Santana do Livramento, southern Brazil, and subjected to chemical fractionation of P. Phosphorus application, especially to the 30-year-old vineyard 2, increased the inorganic P content down to a depth of 20 cm, mainly in the labile fractions extracted by anion-exchange resin and NaHCO3, in the moderately labile fraction extracted by 0.1 and 0.5 mol L-1 NaOH, and in the non-labile fraction extracted by 1 mol L-1 HCl, indicating the possibility of water eutrophication. Phosphorus application and grapevine cultivation time increased the P content in the organic fraction extracted by NaHCO3 from the 0-5 cm layer, and especially in the moderately labile fraction extracted by 0.1 mol L-1 NaOH, down to a depth of 20 cm.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Program from the dedication ceremony of the new U.S. 61 between Interstate 80 and U.S. 30 near De Witt. This section provides motorists with a safe and convenient four-lane highway.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

ABSTRACT An alternative for recovery of areas degraded by coal mining is revegetation with rapidly growing leguminous trees, which often do not establish in low fertility soils. The objective of this study was to evaluate the efficiency of native rhizobia isolated from coal mining areas in the nodulation and growth of leguminous trees. We isolated 19 strains of rhizobia from a degraded soil near Criciúma, SC, Brazil, and evaluated the nodulation and growth-promoting capacity of the inoculated isolates for bracatinga (Mimosa scabrella), maricá (M. bimucronata) and angico-vermelho (Parapiptadenia rigida). Isolates UFSC-B2, B6, B8, B9, B11 and B16 were able to nodulate bracatinga, providing average increases of 165 % in shoot dry matter, with a significant contribution to N accumulation. Isolates UFSC-B5, B12, and M8 favored nodulation and growth of maricá, especially isolate UFSC-B12, which promoted increases of 370 % in N accumulation compared to treatment with N fertilizer. All strains were inefficient in promoting growth and N uptake by angico-vermelho. In conclusion, isolation and use of selected rhizobia for bracatinga and maricá plant inoculation can contribute to the growth and accumulation of N, with prospects for use in programs for revegetation of degraded soils in coal mining areas.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Abstract In this study, chromosomal inversion polymorphism data for a natural population of Drosophila subobscura from a swampy region near the town of Apatin (Serbia) were compared with data for the same population collected approximately 15 years earlier. The pattern of chromosomal inversion polymorphism changed over time. There were significant increases in the frequency of characteristic southern latitude ("warm" adapted) chromosomal arrangements and significant decreases in the frequency of characteristic northern latitude ("cold" adapted) chromosomal arrangements in the O and U chromosomes. The chromosomal arrangements O3+4 and O3+4+22 (derived from the O3+4 arrangement)showed significant increases in 2008 and 2009 with regard to the 1994 sample. There was also a significant increase (~50%) in the U1+2 arrangement, while U1+8+2 (a typical southern arrangement) was detected for the first time. Since the Apatin swampy population ofD. subobscura has existed for a long time in a stable habitat with high humidity that has not been changed by man our results indicate that natural selection has produced chromosomal changes in response to the increase in temperature that has occurred in the Balkan Peninsula of central southeastern European. Key words: chromosomal inversions, Drosophila subobscura, global warming, karyotypes.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

In the last 50 years, we have had approximately 40 events with characteristics related to financial crisis. The most severe crisis was in 1929, when the financial markets plummet and the US gross domestic product decline in more than 30 percent. Recently some years ago, a new crisis developed in the United States, but instantly caused consequences and effects in the rest of the world.This new economic and financial crisis has increased the interest and motivation for the academic community, professors and researchers, to understand the causes and effects of the crisis, to learn from it. This is the one of the main reasons for the compilation of this book, which begins with a meeting of a group of IAFI researchers from the University of Barcelona, where researchers form Mexico and Spain, explain causes and consequences of the crisis of 2007.For that reason, we believed this set of chapters related to methodologies, applications and theories, would conveniently explained the characteristics and events of the past and future financial crisisThis book consists in 3 main sections, the first one called "State of the Art and current situation", the second named "Econometric applications to estimate crisis time periods" , and the third one "Solutions to diminish the effects of the crisis". The first section explains the current point of view of many research papers related to financial crisis, it has 2 chapters. In the first one, it describe and analyzes the models that historically have been used to explain financial crisis, furthermore, it proposes to used alternative methodologies such as Fuzzy Cognitive Maps. On the other hand , Chapter 2 , explains the characteristics and details of the 2007 crisis from the US perspective and its comparison to 1929 crisis, presenting some effects in Mexico and Latin America.The second section presents two econometric applications to estimate possible crisis periods. For this matter, Chapter 3, studies 3 Latin-American countries: Argentina, Brazil and Peru in the 1994 crisis and estimates the multifractal characteristics to identify financial and economic distress.Chapter 4 explains the crisis situations in Argentina (2001), Mexico (1994) and the recent one in the United States (2007) and its effects in other countries through a financial series methodology related to the stock market.The last section shows an alternative to prevent the effects of the crisis. The first chapter explains the financial stability effects through the financial system regulation and some globalization standards. Chapter 6, study the benefits of the Investor activism and a way to protect personal and national wealth to face the financial crisis risks.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

PURPOSE OF REVIEW: Mycoplasma hominis and Ureaplasma urealyticum may colonize the human genital tract and have been associated with adverse pregnancy outcomes. Chorioamnionitis, spontaneous preterm labour and preterm premature rupture of membranes are significant contributors to neonatal morbidity and mortality. However, as these bacteria can reside in the normal vaginal flora, there are controversies regarding their true role during pregnancy and thus the need to treat these organisms. RECENT FINDINGS: We review here the recent data on the epidemiology of mycoplasmas and their clinical role during pregnancy. The association of these organisms with preterm labour has been suggested by many observational studies, but proof of causality remains limited. PCR is an excellent alternative to culture to detect the presence of these organisms, but culture allows antibiotic susceptibility testing. Whether antimicrobial treatment of mycoplasma-colonized pregnant patients can effectively reduce the incidence of adverse pregnancy outcomes warrants further investigations. SUMMARY: The role of Mycoplasma spp. and U. urealyticum in adverse pregnancy outcomes is increasingly accepted. However, sole presence of these microorganisms in the vaginal flora might be insufficient to cause pathological issues, but their combination with other factors such as bacterial vaginosis or cervical incompetence may be additionally needed to induce preterm birth.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

The enzyme beta-glucosidase hydrolyses the isoflavone glucosides developing aglycones, which are compounds with anticancer effects, that are also related with the astringency observed in soybean flavor. Due to the importance of this enzyme, a study was carried out to determine beta-glucosidase activity in soybean (Glycine max (L.) Merrill) cultivars with different contents of isoflavone glucosides (enzyme substrate). The enzyme activity was determined in 51 soybean cultivars sowed in Londrina (latitude 23ºS), in Paraná State, Brazil, and in the cultivar IAS 5 from soybean production regions of different Brazilian states. Among the cultivars, a range of variability of 176.1 to 96.3 units of enzyme activity (cultivars IAC-2 and Embrapa 2, respectively) was observed. A significant variability among cultivars could suggest genetic differences. In the states of Rio Grande do Sul, Paraná and Mato Grosso do Sul, the cultivar IAS 5 presented similar average of beta-glucosidase activity: 132.1, 131.9 and 132.5 units, respectively. Among locations in the states, the cultivar IAS 5 presented a variability for enzyme activity from 138.8 to 124.8 units, which were statistically different. In spite of statistics, the numerical values were not too different to assume that environmental conditions affected enzyme activity. A non-significative correlation for isoflavone glucoside concentrations and enzyme activity was observed among cultivars.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

The objective of this work was to verify if reflected energy of soils can characterize and discriminate them. A spectroradiometer (Spectral reflectance between: 400-2,500 nm) was utilized in laboratory. The soils evaluated are located in Bauru region, SP, Brazil, and are classified as Typic Argiudoll (TR), Typic Eutrorthox (LR), Typic Argiudoll (PE), Typic Haplortox (LE), Typic Paleudalf (PV) and Typic Quartzipsamment (AQ). They were characterized by their spectral reflectance as for descriptive conventional methods (Brazilian and International) according to the types of spectral curves. A method for the spectral descriptive evaluation of soils was established. It was possible to characterize and discriminate the soils by their spectral reflectance, with exception for LR and TR. The spectral differences were better identified by the general shape of spectral curves, by the intensity of band absorption and angle tendencies. These characteristics were mainly influenced by organic matter, iron, granulometry and mineralogy constituents. A reduction of iron and clay contents, which influenced higher reflectance intensity and shape variations, occurred on the soils LR/TR, PE, LE, PV and AQ, on that sequence. Soils of the same group with different clay textures could be discriminated. The conventional descriptive evaluation of spectral curves was less efficient on discriminating soils. Simulated orbital data discriminated soils mainly by bands 5 and 7.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

The objectives of this study were to establish DRIS norms for sugarcane crop, to compare mean yield, foliar nutrient contents and variance of nutrient ratios of low- and high-yielding groups and to compare mean values of nutrient ratios selected as the DRIS norms of low- and high-yielding groups. Leaf samples (analyzed for N, P, K, Ca, Mg, S, Cu, Mn and Zn contents) and respective yields were collected in 126 commercial sugarcane fields in Rio de Janeiro State, Brazil and used to establish DRIS norms for sugarcane. Nearly all nutrient ratios selected as DRIS norms (77.8%) showed statistical differences between mean values of the low- and high-yielding groups. These different nutritional balances between the low- and high-yielding groups indicate that the DRIS norms developed in this paper are reliable. The DRIS norms for micronutrients with high S²l /S²h ratio and low coefficient of variation found can provide more security to evaluate the micronutrient status of sugarcane.

Relevância:

90.00% 90.00%

Publicador:

Resumo:

Over three years the postharvest quality of 'Marli' peaches harvested from the integrated (IFP) and conventional production (CFP) systems was evaluated. The peaches were harvested from commercial orchards of Prunus persica at two locations close to the city of São Jerônimo, RS, Brazil, and stored at 0.5°C for 10, 20 or 30 days. The peaches were evaluated at harvest, at retrieval from storage and after ripening periods at 20°C. No differences in fruit weight losses were determined. Decay incidence was low, and no differences were detected amongst systems in both 2001 and 2002 seasons, but in the 2000 season CFP peaches were more decayed. Flesh firmness of peaches from the IFP system were greater than CFP fruits in the years 2000 and 2001. In 2002, firmness changed little during storage and ripening. Peaches from the IFP in 2000 had higher titratable acidity and lower soluble solids. In the 2000 season, flesh browning was observed in decayed fruits, always at ripening after 20 or 30 days of cold storage Chilling injuries such as browning, woolliness and leatheriness ocurred in 2002. There were no differences amongst systems related to peach quality.