Assessment of changes in the ichthyofauna in a tropical reservoir in south-eastern Brazil: Consequences of global warming?

Increases in temperatures over the last century, more intensively after the eighties, were recorded in several databases for the south-eastern Brazil. These increases are likely to change fish communities in aquatic systems by decreasing abundances, biomass and sizes of some species more sensitive to climate change. Reservoirs may be particularly susceptible to the effects of climate change, as they isolate previously connected areas limiting fish dispersal and migration, as well as increasing water temperature and thermal stratification. We assessed temporal changes in the abundance and biomass of the ichthyofauna in an isolate reservoir (inflowing waters from small tributaries in a highland region) aiming to associate changes with climate effects over three decades (1990, 2000, 2010). Two abundant native species, a loricariid Loricariichthys castaneus (Castelnau, 1855) and a cichlid Geophagus brasiliensis (Quoy & Gaimard, 1824), were selected to assess eventual response to climate changes in their geographical distribution in the Southeast Atlantic Hydrographic Region, considering different carbon emission scenarios using ecological niche models. A decrease in the densities and biomass of the ichthyofauna and of the two selected species were observed in both summer and winter over the three decades, coinciding with increases in temperatures. These decreases were correlated with increases in positive anomalies of temperature, which may be an indicator of climatic changes, although with low explanation of the data variation. The mean size of L. castaneus decreased between the nineties and 2010, whereas no significant trend was found for the size of G. brasiliensis. Our predictions of new area for future adequacy indicated a loss in the distribution area for both species (mainly for G. brasiliensis), considering the most pessimistic scenario for 2050 and 2070, possibly due to climatic changes. Both hydroelectric dams and global warming pose threats to freshwater fish diversity, and both will interact. Changes observed in the fish assemblage over the last decades were essential for an assessment of the consequences of global warming in this type of reservoir combining larger scale studies with future projections.     

Chemical, Sensorial and Rheological Properties of a New Organic Rice Bran Beverage

Rice bran is a solid residue from rice polishing that is used in animal nutrition and rice oil production. Cultivation conditions with agro-toxics, lipids instability, and tendency for mycotoxin contamination restrict its application in human nutrition. Therefore, organic agriculture is an alternative to use the properties of rice bran. Rice bran beverage is a new cereal product from organic rice. This work presents the preliminary results of the chemical and rheological studies of a bath pasteurized rice bran beverage. Compared with integral defatted milk, soy extracts, and brown rice low-fat milk, the rice bran beverage studied in this work presents itself as an important source of minerals and unsaturated lipids. All essential amino acids were found in this product. Glutamic and aspartic acids were predominant. Bath pasteurization at boiling water temperature for 15 and 30 min was adequate for microbiological safety. Refrigeration storage for 20 days, evaluated by pH and acidity variations, was ideal for assessment of the beverage conservation time. The beverage viscosity was of the Newtonian standard behavior, and its viscosity during storage was not a good parameter to evaluate shelf life. Sensory preference tests showed positive perspectives for this new beverage.     

Water quality,trend detection,and causality

This paper begins by discussing the detection of a trend in water quality time series. Using the method of Box and Jenkins, an example of trend identification in sediment loading in the Iowa River is presented. Subsequent to the identification of a trend, an approach is suggested whereby the factors giving rise to the trend can be detected. For the example being considered, it is indicated that the cropping practices in the watershed have a significant impact on the detected trend. Thus, each 1% increase in the area of corn and soybeans planted results in about a 0.42% increase in sediment loading.     

Effect of soil moisture on the release of alachlor from alginate-based controlled-release formulations

The release of alachlor from controlled-release formulations (CRFs) based on alginate-montmorillonite matrices into aqueous polyethylene glycol (PEG) solutions of different concentrations and into a soil at different moisture contents was studied. In distilled water and in PEG-containing solutions displaying -0.1 MPa potential and up, the beads imbibe water and swell. The ensuing increase in weight is about 5%, and the increase in the bead's diameter is about 10%. At water potentials of -0.5 MPa and lower, loss of weight and shrinkage of the beads were observed. The changes in weight and diameter of the alginate-clay beads incubated in a Hamra loamy sand soil at 26.5% moisture content (w/w; -0.18 MPa) were similar to those observed in PEG solutions of >-0.5 MPa moisture potential. The weight and diameter losses observed in the drier soils (12.0 and 7.1% water content; -0.49 and -1.11 MPa) were similar to those in the more concentrated PEG solutions. A decrease in the rate of release of the active ingredient from the beads into soil was observed as the water potential decreased (drier soils). The release of the active ingredient from the investigated CRFs displayed a linear relationship to the square root of time, suggesting a diffusion-controlled-release rate. Data extracted from this relationship enabled the formulation of a mathematical model that correlates rate of release to water content.     

Expression of relaxin receptor LRG7, canine relaxin, and relaxin-like factor in the pelvic diaphragm musculature of dogs with and without perineal hernia

OBJECTIVES: To compare the expression of canine relaxin, relaxin-like factor (RLF), and relaxin receptors within the muscles of the pelvic diaphragm of dogs with perineal hernia (PH) and clinically normal dogs. STUDY DESIGN: In vivo comparative study. ANIMALS: Fifteen client-owned intact male dogs with PH were studied. Four mature intact male dogs with no evidence of perineal pathology served as controls. METHODS: Biopsy samples from the levator ani, coccygeus, and internal obturator muscles were obtained. RNA samples were reverse transcribed and analyzed by real-time PCR for the expression of canine relaxin receptor LRG7, relaxin, and RLF. RESULTS: Significantly higher expression levels of canine relaxin receptors occurred in the musculature of the pelvic diaphragm and internal obturator muscle in dogs with PH compared with normal dogs. Expression of canine RLF revealed no significant difference between dogs with PH and controls. The difference in the expression of canine relaxin between groups was not statistically significant. CONCLUSIONS: Relaxin receptor up-regulation occurs in the coccygeus, levator ani, and internal obturator muscles of dogs with PH. CLINICAL RELEVANCE: The higher expression of relaxin receptors within the muscles of the pelvic diaphragm in dogs with PH suggests that relaxin might play a role in the pathogenesis of PH. Atrophy of these muscles, which predisposes to PH, may be attributable to increased relaxin activity.     

Genetic association between DNA fingerprint fragments and loci controlling agriculturally important traits in avocado (Persea americana Mill.)

Summary Associations between DNA fingerprint fragments and 16 avocado quantitative trait loci were tested for in two avocado tamilies by one way analysis of variance and multiple regression analysis. Based on these two analyses the fragments P4, P8, E2 and E5 in Pinkerton × Ettinger progeny were found to be associated with harvest duration, skin color, skin thickness and skin surface, respectively. The fragments P1, P8, B1 and B4 in the Pinkerton × Bacon progeny (half sibs of the original population) were found to be associated with fruit weight, skin color, seed size and peeling, respectively. Based on the original Pinkerton progeny as well as on the half sibs progeny, the fragment P8 was found to be associated with black-purple fruit skin color.The fragment pattern intensity of DNA pools of progeny having either green or black-purple fruit skin color —supported these data. These results are interpreted as genetic-linkage between the DNA fingerprint fragment P8 and locas (1) regulating fruit skin color in avocado.     

Long-term growth, water consumption and yield of date palm as a function of salinity

Actual measurements of water uptake and use, and the effect of water quality considerations on evapotranspiration (ET), are indispensable for understanding root zone processes and for the development of predictive plant growth models. The driving hypothesis of this research was that root zone stress response mechanisms in perennial fruit tree crops is dynamic and dependent on tree maturity and reproductive capability. This was tested by investigating long-term ET, biomass production and fruit yield in date palms (Phoenix dactylifera L., cv. Medjool) under conditions of salinity. Elevated salinity levels in the soil solution were maintained for 6 years in large weighing-drainage lysimeters by irrigation with water having electrical conductivity (EC) of 1.8, 4, 8 and 12 dS m⁻¹. Salinity acted dynamically with a long-term consequence of increasing relative negative response to water consumption and plant growth that may be explained either as an accumulated effect or increasing sensitivity. Sensitivity to salinity stabilized at the highest measured levels after the trees matured and began producing fruit. Date palms were found to be much less tolerant to salinity than expected based on previous literature. Trees irrigated with low salinity (EC = 1.8 dS m⁻¹) water were almost twice the size (based on ET and growth rates) than trees irrigated with EC = 4 dS m⁻¹ water after 5 years. Fruit production of the larger trees was 35-50% greater than for the smaller, salt affected, trees. Long term irrigation with very high EC of irrigation water (8 and 12 dS m⁻¹) was found to be commercially impractical as growth and yield were severely reduced. The results raise questions regarding the nature of mechanisms for salinity tolerance in date palms, indicate incentives to irrigate dates with higher rather than lower quality water, and present a particular challenge for modelers to correctly choose salinity response functions for dates as well as other perennial crops.     

Long-term study of above- and below-ground biomass production in relation to nitrogen and carbon accumulation dynamics in a grey alder (Alnus incana (L.) Moench) plantation on former agricultural land

In the Northern and Baltic countries, grey alder is a prospective tree species for short-rotation forestry. Hence, knowledge about the functioning of such forest ecosystems is critical in order to manage them in a sustainable and environmentally sound way. The 17-year-long continuous time series study is conducted in a grey alder plantation growing on abandoned agricultural land. The results of above- and below-ground biomass and production of the 17-year-old stand are compared to the earlier published respective data from the same stand at the ages of 5 and 10 years. The objectives of the current study were to assess (1) above-ground biomass (AGB) and production; (2) below-ground biomass: coarse root biomass (CRB), fine root biomass (FRB) and fine root production (FRP); (3) carbon (C) and nitrogen (N) accumulation dynamics in grey alder stand growing on former arable land. The main results of the 17-year-old stand were as follows: AGB 120.8 t ha^?1; current annual increment of the stem mass 5.7 t ha year^?1; calculated CRB 22.3 t ha^?1; FRB 81 ± 10 g m^?2; nodule biomass 31 ± 19 g m^?2; fine root necromass 11 ± 2 g m^?2; FRP 53 g DM m^?2 year^?1; fine root turnover rate 0.54 year^?1; and fine root longevity 1.9 years. FRB was strongly correlated with the stand basal area and stem mass. Fine root efficiency was the highest at the age of 10 years; at the age of 17 years, it had slightly reduced. Grey alder stand significantly increased N and C_org content in topsoil. The role of fine roots for the sequestration of C is quite modest compared to leaf litter C flux.