34 resultados para Unconstrained and convex optimization
em Scielo Saúde Pública - SP
Resumo:
Thirty heads with the neck segment of Caiman latirostris were used. The animals were provided from a creation center called Mister Caiman, under the authorization of the Brazilian Institute of Environment and Renewable Natural Resources (Ibama). Animals were sacrificed according to the slaughtering routine of the abattoir, and the heads were sectioned at the level of the third cervical vertebra. The arterial system was washed with cold saline solution, with drainage through jugular veins. Subsequently, the system was filled with red colored latex injection. Pieces were than fixed in 20% formaldehyde, for seven days. The brains were removed, with a spinal cord segment, the duramater removed and the arteries dissected. At the level of the hypophysis, the internal carotid artery gave off a rostral branch, and a short caudal branch, continuing, naturally, as the caudal cerebral artery. This artery projected laterodorsalwards and, as it overpassed the optic tract, gave off its I (the first) central branch. Penetrated in the cerebral transverse fissure, emitting the diencephalic artery and next its II (second) central branch. Still inside the fissure, originated occipital hemispheric branches and a pineal branch. Emerged from the cerebral transverse fissure, over the occipital pole of the cerebral hemisphere. Projected rostralwards, sagital to the cerebral longitudinal fissure, as interhemispheric artery. This artery gave off medial and convex hemispheric branches to the respective surfaces of the cerebral hemispheres, anastomosed with its contralateral homologous, forming the common ethmoidal artery. This artery entered the fissure between the olfactory peduncles, emerging ventrally and dividing into ethmoidal arteries, right and left, which progressed towards the nasal cavities, vascularizing them. The territory of the caudal cerebral artery included the most caudal area of the base of the cerebral hemisphere, its convex surface, the olfactory peduncles and bulbs, the choroid plexuses and the diencephalus with its parietal organs.
Resumo:
The Shadow Moiré fringe patterns are level lines of equal depth generated by interference between a master grid and its shadow projected on the surface. In simplistic approach, the minimum error is about the order of the master grid pitch, that is, always larger than 0,1 mm, resulting in an experimental technique of low precision. The use of a phase shift increases the accuracy of the Shadow Moiré technique. The current work uses the phase shifting method to determine the surfaces three-dimensional shape using isothamic fringe patterns and digital image processing. The current study presents the method and applies it to images obtained by simulation for error evaluation, as well as to a buckled plate, obtaining excellent results. The method hands itself particularly useful to decrease the errors in the interpretation of the Moiré fringes that can adversely affect the calculations of displacements in pieces containing many concave and convex regions in relatively small areas.
Resumo:
The Consumers' interest for products with caloric reduction has increased, and their development is a technological challenge. The consumption of cakes has grown in importance and the demand for dietary products has stimulated the use of sweeteners and the optimization of bakery products. The consumption of fibers is related to chronic diseases prevention. Pumpkin seeds (maximum Cucurbita, L.), rich in fibers, can be used as a source of fiber in food products. A gluten-free diet is not easy to follow since gluten free products are not always available. The objective of this work was to perform a physicochemical characterization of cakes prepared with flours blends (FB) based on Pumpkin Seed Flour (PSF). The cakes were elaborated with FB in the ratios of 30:70 (C30) and 40:60 (C40) of PSF and cornstarch (CS), respectively. The results showed gluten absence and near-neutral pH. The chemical analysis of C30 and B40 showed increase of ashes, lipids, proteins, and insoluble dietary fiber and a decrease in the content of carbohydrates and calories. The chemical composition of C40 presented the greatest content of lipids, proteins, and dietary fibers, the lowest content of calories, and the best physical parameters. Therefore, both products proved suitable for human consumption.
Resumo:
The assessment of spatial uncertainty in the prediction of nutrient losses by erosion associated with landscape models is an important tool for soil conservation planning. The purpose of this study was to evaluate the spatial and local uncertainty in predicting depletion rates of soil nutrients (P, K, Ca, and Mg) by soil erosion from green and burnt sugarcane harvesting scenarios, using sequential Gaussian simulation (SGS). A regular grid with equidistant intervals of 50 m (626 points) was established in the 200-ha study area, in Tabapuã, São Paulo, Brazil. The rate of soil depletion (SD) was calculated from the relation between the nutrient concentration in the sediments and the chemical properties in the original soil for all grid points. The data were subjected to descriptive statistical and geostatistical analysis. The mean SD rate for all nutrients was higher in the slash-and-burn than the green cane harvest scenario (Student’s t-test, p<0.05). In both scenarios, nutrient loss followed the order: Ca>Mg>K>P. The SD rate was highest in areas with greater slope. Lower uncertainties were associated to the areas with higher SD and steeper slopes. Spatial uncertainties were highest for areas of transition between concave and convex landforms.
Resumo:
This paper is a translation from IUPAC nomenclature document by K. Danzer and L. A. Currie (Pure Appl. Chem., 1998, 70(4), 993-1014). Its goal is to establish an uniform and meaningful approach to terminology (in Portuguese), notation, and formulation for calibation in analytical chemistry. In this first part, general fundamentals of calibration are presented, namely for both relationships of qualitative and quantitative variables (relations between variables characterizing certain types analytes of the measured function on the other hand and between variables characterizing the amount or concentration of the chemical species and the intensities of the measured signals, on the other hand). On this basis, the fundamentals of the common single component calibration (Univariate Calibration) which models the relationship y = f(x) between the signal intensities y and the amounts or concentrations x of the analyte under given conditions are represented. Additional papers will be prepared dealing with extensive relationships between several intensities and analyte contents, namely with multivariate calibrations and with optimization and experimental design.
Resumo:
This work describes, through examples, a simple way to carry out experimental design calculations applying an spreadsheets. The aim of this tutorial is to introduce an alternative to sophisticated commercial programs that normally are too complex in data input and output. An overview of the principal methods is also briefly presented. The spreadsheets are suitable to handle different types of computations such as screening procedures applying factorial design and the optimization procedure based on response surface methodology. Furthermore, the spreadsheets are sufficiently versatile to be adapted to specific experimental designs.
Resumo:
Process Analytical Chemistry (PAC) is an important and growing area in analytical chemistry, that has received little attention in academic centers devoted to the gathering of knowledge and to optimization of chemical processes. PAC is an area devoted to optimization and knowledge acquisition of chemical processes, to reducing costs and wastes and to making an important contribution to sustainable development. The main aim of this review is to present to the Brazilian community the development and state of the art of PAC, discussing concepts, analytical techniques currently employed in the industry and some applications.
Resumo:
Thermophilic Bacillus sp. SMIA-2, produced protease when grown on apple pectic, whey protein and corn step liquor medium, whose concentration was varied from 3 to 10 gL-1, according to the central composite design 2³. The experiments were conducted in shaker, at 50 °C, 150 rpm and initial pH 6.5. The results revealed that the culture medium affected both, cell growth and enzyme production. After graphical and numerical optimization procedure, the enzyme production reached its maximum value at 30 h fermentation, reaching, approximately, 70 U protein mg-1, suggesting that this process was partially associated to the growth.
Resumo:
The convenience of the multivariate optimization of SPME procedures through ANOVA calculated using Doehlert designs has been demonstrated for twelve PCBs in the complex matrix of milk. For this study, the main parameters of the extraction were selected and valued through univariate and multivariate optimization. In addition, the analysis of variance allowed identification of the statistically significant variables in this model: high temperature (95 ºC) and ionic strength (36% m/v) proved significant for all the PCBs while intermediate time (70 min) and low methanol concentration (5% v/v) also contributed to the extraction of the majority of these PCBs.
Resumo:
The ferns Anemia tomentosa (Sav.) Sw. var. anthriscifolia (Schrad.) Mickel and Anemia villosa Humb. & Bonpl. ex Willd. are widely associated with vegetation islands on rocky outcrops in Rio de Janeiro. Both species are desiccation tolerant. The leaf anatomy of these species was examined aiming to identify morphological characteristics that would allow the establishment of these species in water-scarce environments. The plants were harvested on "Pedra de Itacoatiara" and prepared according to the usual procedures. The petiole has a uniseriate epidermis with lignified cell walls, conical stegmata, and uniseriate multicelular and glandular trichomes. In A. villosa, the stomata protrude in a respiratory line. Under the epidermis the cells have thick, lignified walls. The parenchyma has phenolic compounds and starch grains. The petiole vascular bundles are surrounded by endodermis with Casparian strips and the xylem is V-shaped (A. villosa) or arc-shaped (A. tomentosa var. anthriscifolia). The leaf blades have a uniseriate epidermis with sinuous anticlinal and convex periclinal walls, conical stegmata and chloroplasts on both surfaces. The leaf margins of A. villosa have lignified cells. The guard cells of the stomata on the abaxial surface are on the same level or are raised above ordinary epidermal cells. Multicelular uniseriate trichomes and glandular hairs were observed. The dorsiventral mesophyll has loosely packed chlorenchyma with arm-shaped and H-shaped cells. The vascular bundles are surrounded by endodermis with Casparian strips and with parenchymatic extensions towards the epidermis. Anatomical results were analyzed considering the interaction of these plants with abiotic factors.
Resumo:
The aim of this work was to assess the influence in the diagnostic value for human hydatid disease of the composition of bovine hydatid cyst fluid (BHCF) obtained from fertile (FC) and non-fertile cysts (NFC). Eight batches from FC and 5 from NFC were prepared and analysed with respect to chemical composition: total protein, host-derived protein, carbohydrate and lipid contents. No differences were observed in the first two parameters but carbohydrate and lipid contents were shown to be higher in batches from FC than in those from NFC. Bands of 38 and 116 kD in SDS-PAGE profiles were observed to be present in BHCF from FC only. Two pools were prepared from BHCF batches obtained from FC (PFC) and NFC (PNFC), respectively. Antigen recognition patterns were analysed by immunoblot. Physicochemical conditions for adsorption of antigens to the polystyrene surface (ELISA plates) were optimized. The diagnostic value of both types of BHCF as well as the diagnostic relevance of oxidation of their carbohydrate moieties with periodate were assessed by ELISA using 42 serum samples from hydatid patients, 41 from patients with other disorders, and 15 from healthy donors. Reactivity of all sera against native antigen were tested with and without free phosphorylcholine. The best diagnostic efficiency was observed using BHCF from periodate-treated PFC using glycine buffer with strong ionic strength to coat ELISA plates.
Resumo:
The vast majority of the 1-2 million malaria associated deaths that occur each year are due to anemia and cerebral malaria (the attachment of erythrocytes containing mature forms of Plasmodium falciparum to the endothelial cells that line the vascular beds of the brain). A "model" system"for the study of cerebral malaria employs amelanotic melanoma cells as the "target"cells in an vitro cytoadherence assay. Using this model system we determined that the optimum pH for adherence is 6.6 to 6.8, that high concentrations of Ca²* (50mM) result in increased levels of binding, and that the type of buffer used influences adherence (Bis Tris > MOPS > HEPES > PIPES). We also observed that the ability of infected erythrocytes to cytoadhere varied from (erythrocyte) donor to donor. We have produced murine monoclonal antibodies against P. falciparum-infected red cells which recognized modified forms of human band 3; these inhibit the adherence of infected erythrocytes to melanoma cells in a doso responsive fashion. Antimalarials (chloroquine, quinacrine, mefloquine, artemisinin), on the other hand, affected adherence in an indirect fashion i.e. since cytoadherence is due, in part to the presence of knobs on the surface of the infected erythrocyte, and knob formation is dependent on intracellular parasite growth, when plasmodial development is inhibited so is knob production, and consequently adherence is ablated.
Resumo:
Nickel, although essential to plants, may be toxic to plants and animals. It is mainly assimilated by food ingestion. However, information about the average levels of elements (including Ni) in edible vegetables from different regions is still scarce in Brazil. The objectives of this study were to: (a) evaluate and optimize a method for preparation of vegetable tissue samples for Ni determination; (b) optimize the analytical procedures for determination by Flame Atomic Absorption Spectrometry (FAAS) and by Electrothermal Atomic Absorption (ETAAS) in vegetable samples and (c) determine the Ni concentration in vegetables consumed in the cities of Lorena and Taubaté in the Vale do Paraíba, State of São Paulo, Brazil. By means of the analytical technique for determination by ETAAS or FAAS, the results were validated by the test of analyte addition and recovery. The most viable method tested for quantification of this element was HClO4-HNO3 wet digestion. All samples but carrot tissue collected in Lorena contained Ni levels above the permitted by the Brazilian Ministry of Health. The most disturbing results, requiring more detailed studies, were the Ni concentrations measured in carrot samples from Taubaté, where levels were five times higher than permitted by Brazilian regulations.
Resumo:
The sampling scheme is essential in the investigation of the spatial variability of soil properties in Soil Science studies. The high costs of sampling schemes optimized with additional sampling points for each physical and chemical soil property, prevent their use in precision agriculture. The purpose of this study was to obtain an optimal sampling scheme for physical and chemical property sets and investigate its effect on the quality of soil sampling. Soil was sampled on a 42-ha area, with 206 geo-referenced points arranged in a regular grid spaced 50 m from each other, in a depth range of 0.00-0.20 m. In order to obtain an optimal sampling scheme for every physical and chemical property, a sample grid, a medium-scale variogram and the extended Spatial Simulated Annealing (SSA) method were used to minimize kriging variance. The optimization procedure was validated by constructing maps of relative improvement comparing the sample configuration before and after the process. A greater concentration of recommended points in specific areas (NW-SE direction) was observed, which also reflects a greater estimate variance at these locations. The addition of optimal samples, for specific regions, increased the accuracy up to 2 % for chemical and 1 % for physical properties. The use of a sample grid and medium-scale variogram, as previous information for the conception of additional sampling schemes, was very promising to determine the locations of these additional points for all physical and chemical soil properties, enhancing the accuracy of kriging estimates of the physical-chemical properties.
Resumo:
In this study, different solutions to extract vitamin C were tested. High-performance liquid chromatography was chosen and the conditions were based on isocratic elution in reverse phase column. Dehydroascorbic acid was determined indirectly after its reduction using dithiothreitol. The use of metaphosphoric acid to stabilize the vitamin C was shown to be required and it was necessary to neutralize the pH of the extract to apply dithiothreitol. The average recovery was 90% in collard and tomato samples. The presence of oil did not interfere in extraction and the methodology can be used to analyze stir fried vegetables.