Cotton root volume and root dry matter as function of high soil bulk density and soil water stress

Soil compaction reduces root growth, affecting the yield, especially in the Southern Coastal Plain of the USA. Simulations of the root restricting layers in greenhouses are necessary to develop mechanisms which alleviate soil compaction problems. The selection of three distinct bulk densities based on the Standard Proctor Test is also an important factor to determine which bulk density restricts root penetration. This experiment was conducted to evaluate cotton (Gossypium hirsutum L.) root volume and root dry matter as a function of soil bulk density and water stress. Three levels of soil density (1.2, 1.4, and 1.6 g cm-3), and two levels of water content (70 and 90% of field capacity) were used. A completely randomized design with four replicates in a 3×2 factorial pattern was used. The results showed that mechanical impedance affected root volume positively with soil bulk density of 1.2 and 1.6 g cm-3, enhancing root growth (P>0.0064). Soil water content reduced root growth as root and shoot growth was higher at 70% field capacity than that at 90% field capacity. Shoot growth was not affected by the increase in soil bulk density and this result suggests that soil bulk density is not a good indicator for measuring mechanical impedance in some soils.

Interaction between wave and coastal structure: Validation of two lagrangian numerical models with experimental results marine 2011

Numerical modeling of the interaction among waves and coastal structures is a challenge due to the many nonlinear phenomena involved, such as, wave propagation, wave transformation with water depth, interaction among incident and reflected waves, run-up / run-down and wave overtopping. Numerical models based on Lagrangian formulation, like SPH (Smoothed Particle Hydrodynamics), allow simulating complex free surface flows. The validation of these numerical models is essential, but comparing numerical results with experimental data is not an easy task. In the present paper, two SPH numerical models, SPHysics LNEC and SPH UNESP, are validated comparing the numerical results of waves interacting with a vertical breakwater, with data obtained in physical model tests made in one of the LNEC's flume. To achieve this validation, the experimental set-up is determined to be compatible with the Characteristics of the numerical models. Therefore, the flume dimensions are exactly the same for numerical and physical model and incident wave characteristics are identical, which allows determining the accuracy of the numerical models, particularly regarding two complex phenomena: wave-breaking and impact loads on the breakwater. It is shown that partial renormalization, i.e. renormalization applied only for particles near the structure, seems to be a promising compromise and an original method that allows simultaneously propagating waves, without diffusion, and modeling accurately the pressure field near the structure.

Checklist of freshwater ichthyofauna from coastal streams of Juréia-Itatins Reserve, Southeastern Brazil

The Juréia-Itatins Ecological Station (JIES) is one of the few protected areas in the state of São Paulo, which harbor a significant portion of the Atlantic forest. Although there is high diversity and endemism of fish species in this region, knowledge of the ichthyofauna in JIES is incipient. A total of 4,809 specimens belonging to six orders, 15 families and 31 species were captured during April 2009 to February 2010, using electrofishing, gillnets and traps. The family Characidae was predominant, mainly due to the abundance of freshwater species such as Astyanax ribeirae, Mimagoniates microlepis, and Hollandichthys multifasciatus. Although the estuarine regions were rarely sampled in this study, six brackish water species were captured. In this study, nine species previously unknown from JIES were discovered. Five endangered fish species, endemic to the Atlantic forest, occur at JIES, thus the presence of protected areas, as a conservation measure, is particularly relevant. © 2013 Check List and Authors.

The effects of water molecules on the electronic and structural properties of peptide nanotubes

The self-assembly of short amino acid chains appears to be one of the most promising strategies for the fabrication of nanostructures. Their solubility in water and the possibility of chemical modification by targeting the amino or carboxyl terminus give peptide-based nanostructures several advantages over carbon nanotube nanostructures. However, because these systems are synthesized in aqueous solution, a deeper understanding is needed on the effects of water especially with respect to the electronic, structural and transport properties. In this work, the electronic properties of l-diphenylalanine nanotubes (FF-NTs) have been studied using the Self-Consistent Charge Density-Functional-based Tight-Binding method augmented with dispersion interaction. The presence of water molecules in the central hydrophilic channel and their interaction with the nanostructures are addressed. We demonstrate that the presence of water leads to significant changes in the electronic properties of these systems decreasing the band gap which can lead to an increase in the hopping probability and the conductivity. © the Owner Societies 2013.

Microbiological responses to depuration and transport of native and exotic clams at optimal and stressful temperatures

The microbiological responses of two bivalves species from Tagus estuary, Venerupis pullastra (native clam) and Ruditapes philippinarum (exotic clam) were investigated during 48h of depuration and subsequent simulated transport in semi-dry conditions at two temperatures (4 and 22°C) until reaching 50% lethal time (LT50). Regardless of temperature and species, the maintenance of clams in water for 48h (depuration period) did not affect LT50 during transport. R.philippinarum showed higher survival rates than V.pullastra, always reaching LT50 later, especially at 4°C. Significant differences between clams' species were found in almost all microbiological parameters. This can be related with clams' biological activity and habitat environmental conditions since both clams do not coexist in Tagus estuary. Depuration was efficient to reduce the bacterial load, particularly Escherichia coli, but not efficient to remove Vibrio spp. In both species, the growth of Vibrio spp. was inhibited at 4°C, whereas exponential growth occurred at 22°C. Total viable counts significantly increased in most treatments, while E.coli counts significantly decreased to undetected levels, except for non-depurated R.philippinarum simulated transported at 4°C. Thus, this study highlights the importance of clams depuration for at least 24h in polluted estuarine areas, followed by transport at low temperatures (4°C). © 2013 Elsevier Ltd.

Disentangling the influences of habitat structure and limnological predictors on stream fish communities of a coastal basin, southeastern Brazil

Em ambientes de riacho, fatores relacionados à estrutura dos habitats e limnologia interagem regulando os padrões de transferência de energia e matéria, afetando a composição da comunidade de peixes. Em bacias costeiras do sudeste do Brasil as características limnológicas e estrutura dos habitats diferem entre riachos de águas claras e pretas. Os primeiros são compostos por uma variedade de tipos de substrato, possuem velocidades de corrente mais elevadas e baixa condutividade, enquanto os últimos apresentam substrato arenoso, baixas velocidades de corrente e águas escuras e ácidas. Neste trabalho analisamos a importância relativa da estrutura dos habitats e das variáveis limnológicas como preditores dos padrões de composição em comunidades de peixes de riachos. Oito riachos de primeira a terceira ordem foram amostrados na planície costeira da bacia do rio Itanhaém. Capturamos 34 espécies e verificamos que a composição das comunidades foi influenciada por fatores estruturais e limnológicos, sendo os primeiros mais importantes. Uma fração de variação que não pode ser totalmente decomposta, deve-se à influência conjunta da limnologia e estrutura dos habitats. Algumas das espécies restritas aos riachos de águas pretas provavelmente apresentam adaptações fisiológicas e comportamentais para lidar com os baixos níveis de pH. Quando foram examinados somente os riachos de águas claras, toda a variação explicada na composição da comunidade de peixes foi atribuída aos fatores estruturais, devido a preferências específicas por diferentes características de hábitats.

Rest stops during road transport: Impacts on performance and acute-phase protein responses of feeder cattle

Angus x Hereford steers (n = 42) and heifers (n = 21) were ranked by gender and BW on d 0 of the experiment and randomly assigned to 1 of 3 treatments: 1) no transport and full access to feed and water (CON); 2) continuous road transport for 1,290 km (TRANS), or 3) road transport for 1,290 km, with rest stops every 430 km (STOP; total of 2 rest stops). Treatments were applied from d 0 to 1 of the experiment. Cattle from TRANS and STOP treatments were transported in separate commercial livestock trailers, within a single 2.1 x 7.2 m compartment, but through the exact same route. During each rest stop, STOP cattle were unloaded and offered mixed alfalfa-grass hay and water for ad libitum consumption for 2 h. Upon arrival of STOP and TRANS on d 1, cattle were ranked by sex and BW within each treatment and assigned to 21 feedlot pens (7 pens/treatment; 2 steers and 1 heifer/pen). Full BW was recorded before (d -1 and 0) treatment application and at the end of experiment (d 28 and 29). Total DMI was evaluated daily from d 1 to 28. Blood samples were collected on d 0 (before loading of TRANS and STOP cattle), 1 (immediately after unloading of TRANS and STOP cattle), 4, 7, 10, 14, 21, and 28. Body weight shrink from d 0 to d 1 was reduced (P < 0.01) in CON compared to TRANS and STOP, and reduced in STOP compared to TRANS. Mean ADG was greater (P < 0.05) in CON compared to TRANS and STOP, but similar (P = 0.68) between TRANS and STOP. No treatment effects were detected (P >= 0.18) on hay, concentrate, and total DMI. Mean G: F was greater (P = 0.05) in CON compared to STOP, tended to be greater (P = 0.08) in CON compared to TRANS, and similar (P = 0.85) between TRANS and STOP. Plasma cortisol concentrations were greater (P <= 0.04) in TRANS compared to CON and STOP on d 1, and greater (P = 0.04) in TRANS compared to CON on d 4. Serum NEFA concentrations were greater (P < 0.01) in TRANS compared to CON and STOP on d 1, and greater (P <= 0.05) in TRANS compared to CON on d 4 and 7. Mean plasma ceruloplasmin concentrations were similar (P = 0.19) among treatments. Plasma haptoglobin concentrations were greater (P <= 0.04) in TRANS compared to CON and STOP on d 1, and in STOP compared to CON on d 1. In conclusion, inclusion of rest stops during a 1,290-km transport prevented the increase in circulating cortisol and alleviated the NEFA and haptoglobin response elicited by transport, but did not improve feedlot receiving performance of transported cattle.

Modelagem do transporte de sedimentos na alta Bacia do Córrego Cachoeirinha (Rio Claro, SP) através do software Soil and Water Assessment Tool (SWAT)

This study aimed to simulate and evaluate the sediment transport in Upper Basin Stream Cachoeirinha in Rio Claro, SP, and compare the results with previous studies performed in the same basin. The modeling software used in this study was Soil and Water Assessment Tool (SWAT), which is a very comprehensive tool that discusses many physical processes. In this work, the hydrosedimentological processes were treated, aiming to understand the sediment production and transport. The Basin Stream Cachoeirinha has an area with predominantly agricultural use, especially sugar cane. The database for inclusion in software was constructed from the following elements: climatic, topographical, soil type and use and land cover of the area, also including the parameters of Modified Universal Soil Loss Equation (MUSLE). The analysis was conducted for a period of 16 years (1994-2010), which is the range of data available from CEAPLA. The results were analyzed in terms of annual runoff and sediment yield. The average sediment delivery in the simulation was 0.94 t/ha/year, while the maximum annual contribution was 7.28 t/ha/year

Chlorophyll a fluorescence in Annona emarginata (Schltdl.) H. Rainer plants subjected to water stress and after rehydration

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Extrinsic factors affecting water absorption in chilling of broiler chicken carcasses

Brazil occupies an outstanding position as a producer and exporter of chicken meat, and the maintenance and expansion of this position require a constant evolution, especially in variables which determine quality. An important quality parameter of poultry meat is the amount of water absorbed by the carcass during processing. In Brazil, carcasses chilling is done by immersion in chilled water. In this process, the carcass is rehydrated and the water lost during transport and initial operations is replaced. At this stage, some care is needed to prevent the absorption of water upper than the level allowed by Brazilian law. This project aimed to evaluate extrinsic factors that can influence the absorption of water by the chicken meat. For this, 144 Cobb chickens divided into 24 groups of six birds were used. At 42 days of age, one chicken of each group, with weight ranging up to 10% more or less from the average of the group, was slaughtered in an experimental pilot scale abattoir where slaughter procedures were conducted under strictly controlled conditions. The chilling procedure was performed following a completely randomized design with factorial arrangement 3x2, where the factors were: three temperatures in the first section of the chilling system (4, 10 and 16ºC) and two degrees of water hardness (hard and soft water), with six treatments and four replications. Brazilian law provides that the water temperature in the first section of the chiller must not be higher than 16ºC, and the length of the carcasses in this section shall not exceed 30 minutes. All carcasses remained in the first section of the chiller for 30 minutes and then were transferred to another tank with water at 4ºC, remaining there until reaching 7ºC. The carcasses were weighed before and after chilling, to evaluate the percentage of water absorbed. The water absorption was influenced by the initial temperature of the water in the chiller and by the water hardness. When initially immersed in water at 4ºC, carcasses water absorption averaged 2.70%, a significantly lower absorption than the values found for the carcasses that were initially immersed in water at 16ºC, 3.83% (p<0.05). The carcasses immersed in water at 10ºC had mean water absorption of 3.66%, not differing from the means observed in the other two treatments (p>0.05). In hard water, the average water absorption was 2.46% and, in soft water, 4.33% (p<0.05). In all treatments, the water absorption did not exceed the limit established by Brazilian legislation, which is a maximum of 8%. This information is important to control the absorption of water by carcasses in chicken meat processing, preventing consumers from being harmed.

Feeding and reproductive dynamics of the damselfish, Stegastes fuscus in the coastal reefs of northeastern Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)