260 research outputs found
Producción de bovinos en la Argentina : de carne somos
Fil: Demarco, Diego. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias; ArgentinaFil: de la Orden, Jorge L. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias; ArgentinaFil: Cervini, Lourdes M. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias; ArgentinaFil: Gil, Susana. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias; ArgentinaA pesar que desde 1990 el stock ganadero ha permanecido relativamente estancado,\nfundamentalmente por la competencia de la actividad agrícola, con mejores márgenes\neconómicos, Argentina sigue siendo un importantísimo productor de carne vacuna, de\nexcelente calidad, el octavo exportador mundial y, por supuesto, el líder en el consumo\nper cápita
Diversidade genética de bovinos de corte por meio de marcadores microssatélites.
Uma alternativa para atender a demanda do mercado por carne de qualidade é a utilização de cruzamentos entre raças zebuínas e taurinas adaptadas. Assim, as raças Bonsmara, Caracu e Senepol (taurinas adaptadas), Angus (taurina não-adaptada) e Nelore (zebuína) foram analisadas utilizando cinco marcadores microssatélites para avaliar a diversidade genética existente dentro e entre as raças e orientar a sua utilização em cruzamentos. Foram analisados 127 touros Bonsmara, Caracu, Senepol, Angus e Nelore e as frequências alélicas foram utilizadas para estimar diversidade gênica, conteúdo de polimorfismo informativo, probabilidade de exclusão e uma matriz de distância genética Euc1ideana. Considerando a média das distâncias Euclideanas, calculadas individualmente para cada marcador, a maior distância genética foi observada entre as raças Angus e Nelore (0,62) e as menores entre Caracu e as demais raças taurinas adaptadas (0,41 e 0,35 para Bonsmara e Senepol, respectivamente). Entre as taurinas adaptadas, a Bonsmara foi a que apresentou a menor distância em relação ao Angus (0,50) e a maior em relação ao Nelore (0,59). A raça Caracu apresentou distância intermediária para Angus (0,53) e Nelore (0,55). As raças Bonsmara e Caracu apresentaram distância genética, em média, 8,3% maior que a raça Senepol para matrizes Angus X Nelore, proporcionando uma expectativa de maior heterose quando cruzadas com estas matrizes
Determination of Tetracycline in Environmental Water Samples at a Graphite-Polyurethane Composite Electrode
A bare graphite-polyurethane composite was evaluated in the tetracycline (TC) determination in natural water samples. Using differential pulse voltammetry (DPV), a linear response was observed in the range of 4.00-40.0 mu mol L-1 with limit of detection of 2.80 mu mol L-1, without the need of surface renewing between successive runs. During the tetracycline determination in water samples, recoveries between 92.6 and 100% were found. The results for TC determination in water samples after a pre-concentration stage agreed with spiked value at a 95% confidence level according to student t-test.O eletrodo compósito grafite-poliuretana foi avaliado na determinação de tetraciclina (TC) em amostras de água natural. Utilizando voltametria de pulso diferencial (DPV), uma resposta linear foi observada no intervalo de 4,00-40,0 µmol L-1 com limite de detecção de 2,80 µmol L-1, sem necessidade de renovação da superfície entre medidas sucessivas. Durante determinação de tetraciclina em amostras de água, foram obtidas recuperações entre 92,6 e 100%. Os resultados para determinação de TC em amostras de água após a etapa de pré-concentração concordam com valor adicionado em um nível de confiança de 95% de acordo com o teste t-student.Brazilian agency Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Brazilian agency Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) [Proc. 08/02590-1, 10/11080-7
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Synthesis of hectorite-TiO2 and kaolinite-TiO2 nanocomposites with photocatalytic activity for the degradation of model air pollutants
We studied the synthesis and photocatalytic activity of small-sized TiO{sub 2} supported on hectorite and kaolinite. Deposition of TiO{sub 2} on the clay mineral surface was conducted by using a sol-gel method with titanium isopropoxide as precursor. Anatase TiO{sub 2} particles formation was achieved by hydrothermal treatment at 180 C. Material characterization was conducted using XRD, SEM, XPS, ICP-OES, BET and porosimetry analysis. Efficiency in synthesizing clay-TiO{sub 2} composites depended strongly on the clay mineral structure. Incorporation of anatase in hectorite, an expandable clay mineral, was found to be very significant (> 36 wt.% Ti) and to be followed by important structural changes at the clay mineral surface. Instead, no major structural modifications of the clay were observed for kaolinite-TiO{sub 2}, as compared with the untreated material. Photocatalytic performance of clay-TiO{sub 2} composites was evaluated with ATR-FTIR following the oxidation of adsorbed toluene and d-limonene, two model air pollutants. In either case, the photocatalytic removal efficiency of these hydrophobic substrates by the synthesized clay-TiO{sub 2} composites was comparable to that observed using pure commercial TiO{sub 2} (Degussa P25)
Combining Native and Malted Triticale Flours in Biscuits: Nutritional and Technological Implications
Triticale-based biscuits were formulated with increasing substitution levels (i.e., 0, 25, 50, 75, and 100% w/w) of malted triticale flour (MTF). The products were analyzed for technological and nutritional characteristics, including the evaluation of the in vitro starch digestion. The results indicated that the substitution of triticale flour with MTF increased (p < 0.05) the total dietary fiber and ash contents. Total starch decreased (p < 0.05) when the level of MTF increased in the formulation, causing an increase in reducing sugars and an increase in the starch hydrolysis index and in the in vitro predicted glycemic index (pGI). The hardness and spread ratio values of biscuits decreased (p < 0.05) with increasing levels of MTF in the recipe. The lightness of doughs and biscuits decreased (p < 0.05) with increasing MTF levels. Overall, MTF could be used to formulate biscuits with higher dietary fiber content than native triticale flour and a medium to high in vitro glycemic index value as a function of the substitution level
Distilled grape pomace as a functional ingredient in vegan muffins: effect on physicochemical, nutritional, rheological and sensory aspects
Wheat-based vegan muffins were formulated with increasing levels (0, 5 and 10 g per 100 g substitutes to flour) of dried grape pomace powder obtained after distillation (DGPP). The DGPP-muffins showed a greater (P < 0.05) total dietary fibre and a lower (P < 0.05) total starch content to the control. The inclusion of DGPP influenced (P < 0.05) both the batter's rheological properties and the baked muffins' technological characteristics, including the baking loss, the volume, the firmness, the spread ratio and the colour. The in vitro antioxidant activity and the phenolic content increased (P < 0.05) following DGPP inclusion. The untargeted phenolic profiling by UHPLC-HRMS revealed an (P < 0.05) increase of several phenolic classes (i.e. free and bound fractions) following the inclusion of DGPP in the recipe. Flavonoids, mainly anthocyanins, were the most abundant compounds. A quantitative descriptive sensory analysis detected the DGPP-vegan muffins showed good sensory acceptability. The vegan muffin with 5 g per 100 g of DGPP obtained the highest overall acceptability score by the panellists
Permselective ion electrosorption of subnanometer pores at high molar strength enables capacitive deionization of saline water
Capacitive deionization with porous carbon electrodes is an energy-efficient water treatment technique limited to the remediation of only brackish water due to the severe efficiency drop at high molar strength. Combining experiment and simulation, our work demonstrates the ability of subnanometer pores for permselective ion electrosorption, which enables capacitive deionization for saline media with high concentrations. Molecular dynamics simulations reveal the origin of permselective ion electrosorption in subnanometer pores at high molar strength. Within the subnanometer range, carbon pores with smaller size become more ionophobic and then express a higher ability of permselective ion electrosorption. This can be understood by the effects of the pore size on the microstructure of in-pore water and ions and the nanoconfinement effects on the ion hydration. These findings provide a new avenue for capacitive deionization of saline water (seawater-like ionic strength) to enable the application of highly concentrated saline media by direct use of porous carbons
The role of anandamide during pregnancy : A short tale about the endocannabinoid system
The success of any species depends on its reproductive efficiency. Sexual procreation is initiated by interactions between a sperm and an egg leading to fertilization. The fertilized egg (embryo) undergoes several mitotic cell divisions, ultimately producing the blastocyst. The nurturing of an offspring within the body and production of a live birth is an enduring task, requiring safeguard regulatory systems at various critical steps. At the moment, there is still a significant knowledge gap in understanding the mechanisms by which a successful pregnancy is achieved. It is difficult to define the hierarchical landscape of the molecular pathways during human pregnancy, because of experimental difficulties and ethical restrictions on research with human embryos. It is hoped that experiments on mice and other animal models that bear certain reproductive similarities with humans combined with those feasible experiments in humans would generate meaningful information to address this critical issue. A deeper insight into these processes will help to generate new ideas and concepts for improving fertility and pregnancy-associated health issues in humans. During the last years, several studies have provided evidence that lipid mediators are important signaling molecules in coordinating a series of events during pregnancy. Increasing evidence points toward the pathophysiological significance of endocannabinoids, a group of bioactive lipid-signaling molecules, in both female and male fertility.Sociedad Argentina de Fisiologí
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