929 resultados para By-environment Interaction


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Objectives: the evidence linking low levels of folic acid and orofacial clefting (OFC) is presently equivocal, There is stronger evidence for the role of folic acid supplementation in protection against the occurrence and recurrence of neural tube defects. The present investigation tested the hypotheses that cleft lip, cleft palate, or both are inversely associated with maternal intake of dietary and supplemental vitamins during the periconceptional period and first 4 months of pregnancy in a Brazilian population.Design: A population-based, case-control study of cleft lip with or without cleft palate (CL(P)) and isolated cleft palate (CP) in a Brazilian population. in structured interviews, case histories were taken from the mothers of a consecutive sample of 450 infants born with nonsyndromic OFC,Results: Mothers who had children with CL(P) were less likely to have been supplemented during the periconceptional period. The statistical significance of the difference in prevalence of the use of supplements between mothers of patients and of controls was greater for the CL(P) group: p < .05 for CP and p < .001 for CL(P). Multivariate analysis confirmed this finding of a protective effect for both types of orofacial cleft,Conclusions: the use of vitamin supplements in the first 4 months of pregnancy was suggestive of a protective effect against the occurrence of CP and CL(P) in this population, the significance of an association between multivitamin supplementation and OFC and the possible role of gene/environment interaction are discussed.

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Milk yield, fat yield, and fat percentage during the first three lactations were studied using New York Holsteins that were milked twice daily over a 305-d, mature equivalent lactation. Those data were used to estimate variances from direct and maternal genetic effects, cytoplasmic effects, sire by herd interaction, and cow permanent environmental effects. Cytoplasmic line was traced to the last female ancestor using DHI records from 1950 through 1991. Records were 138,869 lactations of 68,063 cows calving from 1980 through 1991. Ten random samples were based on herd code. Samples averaged 4926 dams and 2026 cytoplasmic lines. Model also included herd-year-seasons as fixed effects and genetic covariance for direct-maternal effects. Mean estimates of the effects of maternal genetic variances and direct-maternal covariances, as fractions of phenotypic variances, were 0.008 and 0.007 for milk yield, 0.010 and 0.010 for fat yield, and 0.006 and 0.025 for fat percentage, respectively. Average fractions of variance from cytoplasmic line were 0.011, 0.008, and 0.009 for milk yield, fat yield, and fat percentage. Removal of maternal genetic effects and covariance for maternal direct effects from the model increased the fraction of direct genetic variance by 0.014, 0.021, and 0.046 for milk yield, fat yield, and fat percentage; little change in the fraction was due to cytoplasmic line. Exclusion of cytoplasmic effects from the model increased the ratio of additive direct genetic variance to phenotypic variance by less than 2%. Similarly, when sire by herd interaction was excluded, the ratio of direct genetic variance to phenotypic variance increased 1% or less.

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The objective was to study the physical attributes of an Oxisol under fallow or planted with tropical grasses under grazing. The experiment was conducted under the experimental design of randomized blocks in split-plot 2 x 5, being five types of use of soil (Brachiaria ruziziensis, Panicum maximum cv. Aries, Brachiaria brizantha cv. MG5, Panicum maximum cv. Mombaca and fallow) and two evaluation periods (after the first and after the second grazing), with four replications. We evaluated the characteristics of soil bulk density, total porosity, microporosity and macroporosity, after the first and second grazing, and soil resistance to penetration after the second grazing. In layer of 0.00 to 0.10 m, the macroporosity was affected by the interaction between types of use and evaluation periods, while the microporosity and total porosity were reduced and the density was increased from first to second evaluation time. In the subsurface layer (0.10-0.20 m), there were significant effect only of evaluation time, on the macroporosity, total porosity and density. The porosity were reduced, while the density increased from first to second evaluation time. No significant effects of types of use of soil on penetration resistance in all layers studied. The maintenance of an Oxisol under fallow or cultivation with tropical grasses subjected to grazing cattle causes a reduction in total porosity and increased density of surface soil layers (0 to 0.10 m) and subsurface (0.10 - 0.20 m), without promoting changes on resistance to penetration mechanics.

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Maternal antibody (MatAb) transfer is important for early chicken survivability. Diet composition and the amount of feed given to breeder pullets during rearing may affect the development of immunity and the transfer of MatAb to progeny, and could affect progeny performance and resistance to disease. The effects of broiler breeder nutrition and feeding management practices were evaluated for the transfer of MatAb to progeny and for spleen and bursa development at hatching in 2 genetic strains (A and B). In this experiment, the levels of MatAb against Newcastle disease virus were assessed by enzyme-linked immunosorbent assays in serum samples taken of pedigreed chicken progeny from hatching to 13 d of age. Chickens were fed corn-and wheat-based diets, as were their parents. The breeder feeding program and diet type altered the Newcastle disease virus MatAb found in progeny at hatching and affected how long these antibodies were maintained in circulation. Bursal follicle size at hatching was influenced by an interaction among all factors evaluated. Percentage of white pulp in the spleen was affected mainly by genetic strain and diet type, but responses varied according to the breeder feeding program. It was concluded that breeder feeding programs influence MatAb transfer and half-life, and may also affect the early development of lymphoid tissues.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Nonperturbative functions that parametrize off-diagonal hadronic matrix elements of the light-cone leading-twist quark operators are considered. These functions are calculated within the proposed relativistic quark model allowing for the nontrivial structure of the QCD vacuum, special attention being given to gauge invariance. Hadrons are treated as bound states of quarks; strong-interaction quark-pion vertices are described by effective interaction Lagrangians generated by instantons. The parameters of the instanton vacuum, such as the effective radius of the instanton and the quark mass, are related to the vacuum expectation values of the quark-gluon operators of the lowest dimension and to low-energy pion observables. © 2000 MAIK Nauka/Interperiodica.

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A study was conducted during 23 days in order to evaluate the impact of floating aquatic macrophyte on the water quality of a fishpond. Water samples were collected in four points, three inside the pond and one in water inlet. Drastic reduction of dissolved oxygen was observed in the pond, down to 0.87 mg/L. No significant differences (P > 0.05) were observed for total CO 2, nitrite and ammonia with respect to inlet water (P1) and inside the pond (P2, P3 e P4). Chlorophyll a displayed an inverse relationship with phosphorus. Among nitrogen compounds, ammonia presented the highest concentrations except in water inlet where nitrate was higher, 513.33 μg/l, as well as the highest conductivity values. The pH was slightly acid. The results obtained showed that the macrophyte cover promoted an adverse effect in the medium. Under control, aquatic plants might impact positively due to its capacity to reduce total phosphorus and nitrate in the water column as observed in this study.

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Heterogeneity of variances for milk yield (MY) was determined for Brazilian and Colombian herds. The herds were grouped as high or low variability within each country, using as criterion the phenotypic standard deviation (PSD) of MY in the contemporary groups of cows, from the first to the sixth calving. Brazilian and Colombian herds with PSD greater than 1,168 kg or 1,012 kg, respectively, were classified as high variability while the herd groups with values lower than those were classified as low variability. The genetic parameters for MY within each herd group were estimated using bivariate analysis in an animal model and the restricted maximum likelihood method with a derivative free algorithm, using 72,280 first lactations of cows, daughters of 1,880 sires. Heterogeneous variances were found, and Brazilian herds with high PSD had the greatest additive and residual genetic variances and heritability coefficients for MY. MY genetic correlation coefficients between herds of high and low variability within each country were 0.96 and 0.93 while between countries they varied from 0.72 to 0.81, suggesting that there was a reclassification of animals in the two countries and also heterogeneity of variances. This phenomenon leads to the questioning of the strategy of imported semen usage and the need to do genetic evaluations to identify sires with greater genetic potential for (sub) tropical environmental conditions.

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Background: Atherosclerotic coronary artery disease (CAD) is a multifactorial process that appears to be caused by the interaction of environmental risk factors with multiple predisposing genes. It is nowadays accepted that increased levels of DNA damage induced by xenobiotics play an important role in the early phases of atherogenesis. Therefore, in this study, we focus on determining whether genetic variations in xenobiotic-metabolizing [glutathione-S-transferase theta 1 (GSTT1), glutathione-S-transferase mu 1 (GSTM1), cytochrome P450 IIEI (CYP2E1)] and DNA repair [X-ray cross-complementing group 1 (XRCC1)] genes might be associated with increased risk for CAD. Methods: A case-control study was conducted with 400 individuals who underwent subjected to coronary angiography. A total of 299 were patients diagnosed with effective coronary atherosclerosis (case group; >20% obstructive lesion), and 101 (control group) were individuals diagnosed as negative for CAD (<20% obstructive lesions). The polymorphism identifications for GSTM1 and GSTT1, and for CYP2E1 and XRCC1 genes were performed by polymerase chain reaction (PCR) amplification and by PCR-RFLP, respectively. Results and conclusions: The XRCC1 homozygous wild-type genotype Arg/Arg for codon 399 was statistically less pronounced in the case subjects (21.4%) than in controls (38.5%); individuals with the variant XRCC1 genotype had a 2.3-fold increased risk for coronary atherosclerosis than individuals with the wild-type genotype (OR=2.3, 95% CI=1.13-4.69). Conversely, no association between GSTM1, GSTT1, and CYP2E1gene polymorphisms and coronary atherosclerosis was detected. The results provide evidence of the role of DNA damage and repair in cardiovascular disease. © 2011 Elsevier Inc. All rights reserved.

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This experiment aimed to evaluate nutrient intake, total and partial digestibility of dry matter (DM), organic matter (OM), crude protein (CP), neutral (NDF) and acid (ADF) detergent fiber and ruminal parameters, ammonia concentration and volatile fatty acids, in beef cattle fed palisade grass (Brachiaria brizantha cv. marandu) at two regrowth ages, 30 and 60 days, at two times of year (January and February). The intake of DM, OM and CP was influenced by forage age of regrowth with high values for 30 days; this was influenced by time of year, being observed in February the higher intake by animals. DM digestibility average was 60.7 and 59.4% for 30 and 60 days of forage regrowth, respectively, however, was observed effect of interaction between regrowth and time of year, the same comportment was observed for OM, averages were 63.9 and 63% for respective ages of regrowth. CP digestibility was higher for 30 days, 70.8%, than for 60 days of regrowth, 57%. The NDF and ADF digestibilities were influenced by the interaction between regrowth and time of year; their average for 60 days of regrowth in January were respectively 54.8 and 48.5%, being the lower values and, in February, the higher values: 64.9 and 60.4%. The ruminal average digestibility was 79.5, 86.2, 99.4 and 96.7% of the total degradable for DM, OM, NDF and ADF, respectively. Effects of regrowth and time of year there were not recorded. Two hours after the morning meal was observed the ammonia ruminal concentration peak. The acetate:propionate: butirate ruminal ratio observed was 74:18:8(%).

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The use and inadequate exploitation of natural resources is restricting the occurrence of aroeira (Myracrodruon urundeuva F.F. & M.F. Allemão), which now is on the FAO list of endangered species. This exploitation causes a decrease in the genetic base of M. urundeuva populations, which makes it difficult to find genotypes with stability and adaptability to different growing conditions. This study aimed at estimating the genetic variation and productivity, stability and adaptability of progenies of a M. urundeuva natural population, from the Ecological Station of Paulo de Faria-SP, under different planting systems. DBH (diameter at breast height) was evaluated in four progeny tests of M. urundeuva: i) planted with Anandenanthera falcata and Guazuma ulmifolia (TP-AMA); ii) single (TP-ASO); iii) planted with annual crops (TP-SAF) and iv) planted with Corymbia citriodora (TP-EUCA), installed in Selvíria-MS. The experimental design consisted of complete randomized blocks with three replications and a variable number of plants per plot in each of the four planting systems. From the joint analysis of the planting systems studied, it was found that: i) there were variations among planting systems particularly in TP-SAF; ii) only in TP-EUCA it was possible to detect variations among the progenies; iii) the effects of the genotype x environment interaction were not significant. Thereby, the harmonic mean of genotypic values (MHVG), the relative performance of genotypic values from the mean of each site (PRVG) and the harmonic mean of the relative performance of genotypic values (MHPRVG) for DBH showed, respectively: progenies with greater stability, adaptability, and stability and simultaneous adaptability within different planting systems. The use of these selection criteria provided a more refined selection of the best progenies of M. urundeuva under the different planting systems studied.

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Includes bibliography

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)