856 resultados para Condições de otimalidade
Resumo:
In this paper the theoretical fundamentals related to the introduction of NNT (No Net Translation) and NNR (No Net-Rotation) conditions in the realization of a referential are presented. Moreover, aspects related to the implementation are also presented, with special emphasis on the realization from VLBI data, where only scale information is available.
Resumo:
This study presents the results obtained in a field experiment carried out at Glicério, Northwest of São Paulo state, Brazil, whose objective was to analyze changes of selected soil physical properties and water infiltration rates on a Yellow-Red Latosol, under three different management conditions. The experimental design was arranged as completely randomized split-block with twelve treatments, which corresponded to four depths (0-0.05 m; 0.05-0.10 m; 0.10-0.20 m and 0.20-0.40 m) and three conditions of soil use and management with four replications. The soil surface conditions were: conventional tillage (one disking with moulboard plus two levelling passes with harrow), nine months before starting filed experiences; recent conventional tillage (also one disking with moulboard plus two levelling passes with harrow) and native forest. The conventional tillage areas were cropped for about fifteen years with annual cultures. The considered soil general physical properties were: macroporosity, microporosity, total porosity, bulk density, soil moisture and penetration resistance and, in addition; soil water infiltration rates were also recorded. According to our results, differences on general soil physical properties and infiltration rates appeared when both tilled sub-treatments and native forest were compared. Both, plots recently prepared by conventional tillage and those prepared by tillage but left nine months in rest, presented a statistically significant decrease of constant (final) water infiltration rates of 92.72% and 91.91% when compared with native forest plots.
Resumo:
The influence of luminosity and of the use of refuges on the initial development of Steindachneridion sp. Garavello (Siluriforme: Pimelodidae) larvae was evaluated. A thousand larvae 18.02 mm high and 62.2 mg weight were used in an entirely randomized design, with five treatments and four replicates, in 35 L-aquarium during 22 days. The treatments consisted on the following environments: darkness without refuges, clear with artificial refuge, darkness with artificial refuge, clear with natural refuge and clear without refuge. All larvae received the same feeding during the experiment. The best survival rates were found for darkness without refuges, clear with artificial refuge and clear without refuge, with 84, 76 and 70%, respectively. The best development was in darkness and without refuges. The treatment darkness with artificial refuge provided significant differences in relation to the other treatments as far as survival and weight are concerned, showing high heterogeneity for weight. Environment without refuges are the most appropriate for the larval development of this specie.
Resumo:
Eggs and nymphs originated from couples of Rhodnius prolixus obtained from nymphs of the 5th instar were used for biological cycle and biometric studies. The following biological cycle parameters were determined under a temperature of 28°C and relative humidity, varying between 52 - 94% : medium period of incubation: 13.01 days; rate of eggs eclosion: 77.6%; medium period of development of the 1st, 2nd, 3rd, 4 th, 5th instar nymphs : 19.33, 19.09, 20.38, 24.37, 38.14 days, respectively; percentual of deaths in the nymph instar: 26.70, 14.00, 18.26, 17.02, 35.47% respectively; percentual of changes per instar nymphs; 73.30, 86.03, 81.73, 82.97, 64.52%, respectively. Biometric measurements performed, showed that in all the instars the abdomen is the largest segment. In the four first instars, the head is larger than the thorax. In the fifth instar, the head and thorax present are about the same size.
Resumo:
The efficacy of the first ovulation of the breeding season was determined through the response of first pre-ovulatory follicle of the breeding season to hCG, embryo recovery rate, viability of recovered embryos, serum concentrations of progesterone, and response of first CL to PGF 2α. Thirteenth mares that were in vernal transition were accompanied until the first pre-ovulatory follicle was detected. At this moment, the ovulation was induced with 2,500 IU hCG (IV) and the mares were inseminated every other day until ovulation. Seven days after the ovulation, embryo recovery was performed and the progesterone concentration was determined. After detection of the first pre-ovulatory follicle of breeding season with ≥ 25mm, it took 14.92 ± 10.80 days for the follicle to reach the preovulatory size and 18.00 ± 11.08 days to ovulation. After administration of hCG, 11/13 mares ovulated in 48 hours. These follicles growth 2.19 ± 0.86 mm/day on average. Nine of 13 mares (69.2%) produced embryos and all were considered viable after morfological evaluation and fluorescence exams. The CL appeared competent producing 7.39 ± 2.11 ng/ml P 4 on average, and responding to PGF 2α. According to these results the first ovulatory cycle of the year can be utilized to produce viable embryos.
Resumo:
The balance of liming and fertilization practice with nitrogen and zinc could affect the production of the pasture. Thus, the present work has as objective to evaluate the residual effect of the application of calcareous rock, nitrogen, and zinc on the dry matter production of Brachiaria decumbens, during three cuts. For this, an experiment was installed in Selvíria, Brazil, on a distrofic red Latosol, from october 1997 to may 1998. The experimental design was randomized blocks, in a factorial project 3×3×2, with four repetitions. The treatments were three doses of nitrogen: 0, 50, and 100 kg/ha, three doses of lime: 0, 267, and 556 kg/ha, corresponding to 41, 50, and 60% of the levels of base saturation, respectively, and two doses of zinc 0 and 5 kg/ha, applied in the first year and reapplied in the second year, except for the limestone. Four cuts were done in the grass at 10 cm of height, with intervals of 49 days, to obtain the dry matter production. The limestone application in the first year did not provide to residual effect on the production of Brachiaria decumbens. However, the nitrogen fertilization increased the dry matter production of the grass. The application of zinc in the first year and the reapplication in the second year did not result in a productive response of B. decumbens. © 2009 Instituto Nacional de Investigaciones Agricolas INIA.
Resumo:
The analysis of the physical medium in hydrographic basins requires knowledge of the processes involved and characteristics of variables at different geographic scales. Considering the principle that the micro-basins can be categorized, they are then considered territorial units of ideal work for the analysis of hydrologic conditions. The objective of this work was to compare water resources of four hydrographic basins' with different land use and occupation. Five sampling points along the drainage network of hydrographic basins of first order of magnitude and a sampling point in the river mouth of M1 and M4 micro-basins were established. The water collections occurred at monthly intervals from August, 2006 to August, 2007. Temperature (°C), turbidity (NTU), odor, pH, electric conductivity (μS cm-1), dissolved oxygen (mg/L), total dissolved solids (ppm) and total phosphorous (mg/L) were the variables evaluated in the study. The highest variability of the parameters was found in hydrographic basins M2 and M3. The characterization of the hydrologic conditions of the hydrographic micro-basins indicated that agricultural activities, including cultural practices of anthropic activities affect water resources.
Resumo:
Although the management of the coffee crop is well established in Brazil, there is still room for its improvement in relation natural resources available in each region, aiming the increase in productivity. Here are presented results regarding the fate of the fertilizer nitrogen (N) applied to a coffee plantation related to the prevailing soil water conditions. Soil water balances are discussed, which allowed evaluation of the root distribution, determinations of the crop coefficient and of the soil water conditions during the development of the crop. Approximately, 60% of the root system was distributed in the 0-0.3 m soil layer and the average crop coefficient was 1.1 for 3 to 5 year old plants. Using an N label, the 15N, it was possible to study the distribution of N in the plant and in the soil and establishes general N balances, which also include losses like leaching and volatilization. After two years of ammonium sulfate application, at rates of 280 (1st year) and 350 (2nd year) kg.ha-1 of N, in four equal application performed during the period of positive growth rate, the recuperation of fertilizer N were 19.1% by the aerial plant part and 9.4% by the roots, 12.6% remained in the soil and 11.2% in the litter; 0.9% was lost by volatilization and 2.3% by leaching; 26.3% was exported through harvesting and 18.2% remained in non evaluated compartments. From the applied 630 kg.ha -1 of N during the two years, 180 kg.ha -1 of N were found in the plant (shoot and root), which corresponds to 28.6%; 150 kg.ha -1 of N remained available for the next years(soil and litter), and only 20 kg.ha -1 of N were effectively lost (volatilization and leaching).
Resumo:
In the present investigation were evaluated the sanitary conditions of poultry and several types of sausages retailed in Botucatu, São Paulo, Brazil for the determination of the most probable number of coliforms at 45°C/g besides the research of Salmonella using traditional methodology and PCR. In order to do so, 50 samples of poultry and 75 of sausages were collected from nine different establishments in the city, in the period of April to November of 2006. Of the 50 samples of chicken meat, 35 (70%) were out of the microbiologic parameters, according to Brazilian Sanitary Resolution RDC no 12 of Anvisa (>104 coliforms at 45°C/g). In this Resolution, the research of Salmonella is not demanded, but 4 samples (8%) presented the pathogen using the traditional methodology. That presence was confirmed by PCR, which was also positive in another 23, in a total of 27 positive samples (54%). Among 75 samples of sausages, 30 (40%) were out of the allowed limits, with 7 positive samples for Salmonella, using traditional methodology. However, if we consider PCR test, the number of positive samples increases to 42 (56%). Adding this number to coliforms microbiological limits, 86.7% of the analyzed sausages were inappropriate for the consumption.
Resumo:
In areas where human activities, as agriculture, are developed land use contributes to physical, chemical and biological characteristics of water. This study aimed to identify physical and chemical variations of the water monitoring network in 4 first magnitude watersheds with different land use/occupation in the hydrographic basin of the Glori Farm Creek in the city of Taquaritinga, State of Sao Paulo, from February to July, 2005. The methodology consisted of weekly sample water collections to naalyze turbidity, temperature, dissolved oxygen, pH and electric conductivity. The characterization of the hydrological conditions of the watersheds showed that agricultural activities, including the productive system of the sugarcane cultivation, have affected the quality of water resources.
Resumo:
The aim of this research was to evaluate the white mold severity (Sclerotinia sclerotiorum (Lib.) of Bary), bean production components and yield (Phaseolus vulgaris L.), variety Perola, according to the application of procimidone fungicide (Sialex 500), through fungigation (center pivot) and automotive sprayer (Uniport). The study was carried under field production commercial conditions, in Primavera do Leste - MT - Brazil. The experiment consisted of 5 treatments (with 4 repetitions of 4 ha each), all with two procimidone applications (1.2 kg ha-1 each application, same as, 0.6 kg a.i. per hectare) to the 42 and 52 days after seeding. The water depths of 5.5 and 11.0 mm were tested in the application through central pivot (this had your checked uniformity), providing volumes of 55.000 and 110.000 L ha-1, respectively, and the volumes of 120 and 200 L ha-1 in the automotive sprayer. The severity of disease was evaluated by the percentage of the area affected by plant damage using diagramatic grade scale of white mold severity, as described by Azevedo (1998). The values were used to calculate the area under the disease progress curve (AUDPC). They were also analyzed, the number of the fungus apothecia during the crop cycle and the residual sclerotias weight in harvest. On this occasion, it was also evaluated the crop yield parameters: number of plants per plot (final stand), pods per plant, grains per pod, medium weight of 200 grains and productivity of grains. The AUDPC values, apothecia to 42, 49 and 56 days after seeding, sclerotias in 2 soil kg and the crop productivity parameters were submitted to the variance analysis and Tukey Test at 0.05 of probability. This test was also applied in the comparison among the different fungicide application methods, independent of spray volumes in each one. The statistical processing was accomplished by STAT program. The results showed that weren't differences among application techniques studied in relation to productivity parameters, however, best white mold control, smaller apothecia number to 49 and 56 days after seeding and smaller weight of residual sclerotias in the harvest were obtained with the fungigation, independently of the spray volume used.
Resumo:
The objective of this study was to evaluate pig fasting time at the farm (FT= 9, 12, 15 or 18 hours) and pig position into the pig lorry compartment on pork quality through liquid drip loss (DLL), pH1 evaluated at 45 minutes post slaughter and pHu evaluated 24 hours post slaughter. One hundred ninety two females, weighing 133±11 kg, from two farms were used. Pig locations were evaluated on truck compartment considering front, middle and rear (TCL) position and top or botton decks (LUD). The following effects were considered in the statistical model: block (BL= farm), FT, TCL, LUD and the interaction between BL and FT. The FT affected significantly the pH1 of Longissimus dorsi (LD) muscle, and pHu of Semispinalis capitis (SC), Longissimus dorsi (LD) and Semimembranosus (SM) muscles. Fasting time at farm equal or shorter than 12 hours resulted in carcasses with lower pHu values at LD and SM muscles and fasting time above 15 hours resulted in higher pHu on SC. There were no observed effect (p>0.05) of the evaluated sources of variation on DLL. TCL affected pH1 of SC, LD and SM muscles, and pHu of LD and SM muscles. Pigs located in middle or rear position in the lorry had no difference in pH1 of the evaluated muscles. But pigs located in the middle position of the lorry had greater values of pHu on LD and SM. It is stated that pigs fasting time at farm need to be close to 15 hours in aim of obtain higher frequency of pHu values in the normal range (5.55
Resumo:
Incluye Bibliografía
Resumo:
The use of cover crops in the soil causes changes in soil attributes influencing in a series of hydro-physical processes, which also modify the ability of soil to support the many activities that it is intended. Thus, the objective of this study was to evaluate the effect of cover crops on physical attributes of the soil. For this, an experiment was carried out on a Typic Hapludox, Jaboticabal State, Brazil, using cover crops of millet, sunn hemp, jack bean, lab-lab and black velvet bean in no-tillage and fallow area (spontaneous vegetation). The characteristics evaluated were the bulk density, macroporosity, microporosity, total porosity, aggregate stability, penetration resistance and organic matter. The incorporation of cover crops has proved to be a beneficial practice for the physical attributes of the soil, allowing a greater aggregate stability compared to fallow in the depth of 0-0.05 m. All cover crops presented values of soil penetration resistance below the critical value of 2 MPa.
Resumo:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)