988 resultados para Weighted Composition Operators
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PURPOSE: At high magnetic field strengths (B0 ≥ 3 T), the shorter radiofrequency wavelength produces an inhomogeneous distribution of the transmit magnetic field. This can lead to variable contrast across the brain which is particularly pronounced in T2 -weighted imaging that requires multiple radiofrequency pulses. To obtain T2 -weighted images with uniform contrast throughout the whole brain at 7 T, short (2-3 ms) 3D tailored radiofrequency pulses (kT -points) were integrated into a 3D variable flip angle turbo spin echo sequence. METHODS: The excitation and refocusing "hard" pulses of a variable flip angle turbo spin echo sequence were replaced with kT -point pulses. Spatially resolved extended phase graph simulations and in vivo acquisitions at 7 T, utilizing both single channel and parallel-transmit systems, were used to test different kT -point configurations. RESULTS: Simulations indicated that an extended optimized k-space trajectory ensured a more homogeneous signal throughout images. In vivo experiments showed that high quality T2 -weighted brain images with uniform signal and contrast were obtained at 7 T by using the proposed methodology. CONCLUSION: This work demonstrates that T2 -weighted images devoid of artifacts resulting from B1 (+) inhomogeneity can be obtained at high field through the optimization of extended kT -point pulses. Magn Reson Med 71:1478-1488, 2014. © 2013 Wiley Periodicals, Inc.
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The objective of this work was to evaluate the chemical and physical characteristics of grains of soybean (Glycine max) cultivars for food processing. The soybean cultivars evaluated were: grain-type - BRS 133 and BRS 258; food-type - BRS 213 (null lipoxygenases), BRS 267 (vegetable-type) and BRS 216 (small grain size). BRS 267 and BRS 216 cultivars showed higher protein content, indicating that they could promote superior nutritional value. BRS 213 cultivar showed the lowest lipoxygenase activity, and BRS 267, the lowest hexanal content. These characteristics can improve soyfood flavor. After cooking, BRS 267 cultivar grains presented a higher content of aglycones (more biologically active form of isoflavones) and oleic acid, which makes it proper for functional foods and with better stability for processing, and also showed high content of fructose, glutamic acid and alanine, compounds related to the soybean mild flavor. Because of its large grain size, BRS 267 is suitable for tofu and edamame, while small-grain-sized BRS 216 is good for natto and for soybean sprouts production. BRS 216 and BRS 213 cultivars presented shorter cooking time, which may be effective for reducing processing costs.
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The objective of this work was to evaluate the species composition and functional groups of ants in nonagricultural (NA) and in irrigated areas (S, seasonal irrigation; P, irrigation with well water; W, irrigation with wastewater) in an arid agricultural region in central Mexico, throughout 2005 and 2006. A total of 52,358 ants belonging to 6 subfamilies, 21 genera and 39 species was collected using pitfall traps. The species best represented in all plots were: Forelius pruinosus, Pheidole obtusospinosa, Monomorium minimum and Dorymyrmex spp. NA plots recorded the highest density of ants. The highest values for diversity (H') and equitativity (J') were recorded in NA and P plots, while the lowest were recorded in W plots. Cluster analysis showed two different groups regarding species composition: NA-S and W-P. Functional groups recorded were: dominant Dolichoderinae, three species; subordinate Camponotini, five species; hot climate specialists, three species; tropical climate specialists, seven species; cold climate specialists, five species; cryptic species, one species; opportunists, six species; generalized Myrmicinae, nine species. Agricultural activity affects the structure of the ant community with epiedaphic forage, and the constant use of irrigation wastewater in conjunction with intense agricultural practices has negative effect upon species richness of epiedaphic ants.
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INTRODUCTION: Calcium-containing (CaC) crystals, including basic calcium phosphate (BCP) and calcium pyrophosphate dihydrate (CPP), are associated with destructive forms of osteoarthritis (OA). We assessed their distribution and biochemical and morphologic features in human knee OA cartilage. METHODS: We prospectively included 20 patients who underwent total knee replacement (TKR) for primary OA. CaC crystal characterization and identification involved Fourier-transform infra-red spectrometry and scanning electron microscopy of 8 to 10 cartilage zones of each knee, including medial and lateral femoral condyles and tibial plateaux and the intercondyle zone. Differential expression of genes involved in the mineralization process between cartilage with and without calcification was assessed in samples from 8 different patients by RT-PCR. Immunohistochemistry and histology studies were performed in 6 different patients. RESULTS: Mean (SEM) age and body mass index of patients at the time of TKR was 74.6 (1.7) years and 28.1 (1.6) kg/m², respectively. Preoperative X-rays showed joint calcifications (chondrocalcinosis) in 4 cases only. The medial femoro-tibial compartment was the most severely affected in all cases, and mean (SEM) Kellgren-Lawrence score was 3.8 (0.1). All 20 OA cartilages showed CaC crystals. The mineral content represented 7.7% (8.1%) of the cartilage weight. All patients showed BCP crystals, which were associated with CPP crystals for 8 joints. CaC crystals were present in all knee joint compartments and in a mean of 4.6 (1.7) of the 8 studied areas. Crystal content was similar between superficial and deep layers and between medial and femoral compartments. BCP samples showed spherical structures, typical of biological apatite, and CPP samples showed rod-shaped or cubic structures. The expression of several genes involved in mineralization, including human homolog of progressive ankylosis, plasma-cell-membrane glycoprotein 1 and tissue-nonspecific alkaline phosphatase, was upregulated in OA chondrocytes isolated from CaC crystal-containing cartilages. CONCLUSIONS: CaC crystal deposition is a widespread phenomenon in human OA articular cartilage involving the entire knee cartilage including macroscopically normal and less weight-bearing zones. Cartilage calcification is associated with altered expression of genes involved in the mineralisation process.
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Dynamic changes in body weight have long been recognized as important indicators of risk for debilitating diseases. While weight loss or impaired growth can lead to muscle wastage, as well as to susceptibility to infections and organ dysfunctions, the development of excess fat predisposes to type 2 diabetes and cardiovascular diseases, with insulin resistance as a central feature of the disease entities of the metabolic syndrome. Although widely used as the phenotypic expression of adiposity in population and gene-search studies, body mass index (BMI), that is, weight/height(2) (H(2)), which was developed as an operational definition for classifying both obesity and malnutrition, has considerable limitations in delineating fat mass (FM) from fat-free mass (FFM), in particular at the individual level. After an examination of these limitations within the constraints of the BMI-FM% relationship, this paper reviews recent advances in concepts about health risks related to body composition phenotypes, which center upon (i) the partitioning of BMI into an FM index (FM/H(2)) and an FFM index (FFM/H(2)), (ii) the partitioning of FFM into organ mass and skeletal muscle mass, (iii) the anatomical partitioning of FM into hazardous fat and protective fat and (iv) the interplay between adipose tissue expandability and ectopic fat deposition within or around organs/tissues that constitute the lean body mass. These concepts about body composition phenotypes and health risks are reviewed in the light of race/ethnic variability in metabolic susceptibility to obesity and the metabolic syndrome.
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The objective of this work was to quantify the accumulation of the major seed storage protein subunits, β-conglycinin and glycinin, and how they influence yield and protein and oil contents in high-protein soybean genotypes. The relative accumulation of subunits was calculated by scanning SDS-PAGE gels using densitometry. The protein content of the tested genotypes was higher than control cultivar in the same maturity group. Several genotypes with improved protein content and with unchanged yield or oil content were developed as a result of new breeding initiatives. This research confirmed that high-protein cultivars accumulate higher amounts of glycinin and β-conglycinin. Genotypes KO5427, KO5428, and KO5429, which accumulated lower quantities of all subunits of glycinin and β-conglycinin, were the only exceptions. Attention should be given to genotypes KO5314 and KO5317, which accumulated significantly higher amounts of both subunits of glycinin, and to genotypes KO5425, KO5319, KO539 and KO536, which accumulated significantly higher amounts of β-conglycinin subunits. These findings suggest that some of the tested genotypes could be beneficial in different breeding programs aimed at the production of agronomically viable plants, yielding high-protein seed with specific composition of storage proteins for specific food applications.
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The objective of this work was to determine differences in leaf mineral composition between ungrafted and grafted onto (Solanum torvum) eggplant (Solanum melongena), cultivars 'Faselis' and 'Pala', grown in a soil infested with Verticillium dahliae and Meloidogyne incognita, or in a noninfested soil. Grafting increased leaf P and Mn concentrations, and decreased N concentrations, in both soils. Grafting also enhanced leaf Ca concentration of 'Pala', but it did not affect that of 'Faselis' depending on the cropping year. Leaf Mg concentration of grafted plants in infested soil was lower than that of ungrafted ones in noninfested soil. Results showed that, under the same fertilization program, the grafted 'Faselis' plants used the nutrients more efficiently than the 'Pala' ones. Use of S. torvum as a rootstock for 'Faselis' resulted in an effective protection against multiple pathogen infestation. Fertilization may be necessary when grafted 'Faselis' plants are grown in a soil infested with the pathogens, since grafting and infestation generally decrease leaf N, Mg, Ca and Fe concentrations, either by reducing the nutrient concentrations directly or by increasing leaf Mn concentration.
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The objective of this work was to determine the proper levels of protein and energy in diets of Hoplias lacerdae fingerlings. The dietary crude protein (CP) and gross energy (GE) levels for fingerlings of giant trahira were evaluated in a completely randomized 4x3 factorial design with 35, 39, 43 and 47% CP and 4,100, 4,300 and 4,500 kcal kg-1 of GE, and four replicates. The survival rate was 99.22%, and a linear improvement on the performance parameters was detected after increasing diet crude protein levels. Feed conversion ratio decreased with increasing levels of dietary protein and energy in the diets. A significant interaction between crude protein and gross energy was observed over body protein and mineral matter. Body lipid has increased linearly as gross energy in the diet increased. The retention of crude protein and energy showed a linear increasing with rising of crude protein levels in the diet. Crude protein level at 47% provides the best performance and energy retention, independently of the gross energy levels in the diet.
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The addition of some fat co- and by-products to feeds is usual nowadays; however, the regulations of their use are not always clear and vary between countries. For instance, the use of recycled cooking oils is not allowed in the European Union, but they are used in other countries. However, oils recovered from industrial frying processes could show satisfactory quality for this purpose. Here we studied the effects of including oils recovered from the frying industry in rabbit and chicken feeds (at 30 and 60 g/kg, respectively) on the fatty acid (FA) and tocol (tocopherol + tocotrienol) compositon of meat, liver and plasma, and on their oxidative stability. Three dietary treatments (replicated eight times) were compared: fresh non-used oil (LOX); oil discarded from the frying industry, having a high content of secondary oxidation compounds (HOX); and an intermediate level (MOX) obtained by mixing 50 : 50 of LOX and HOX. The FA composition of oil diets and tissues was assessed by GC, their tocol content by HPLC, the thiobarbituric acid value was used to assess tissue oxidation status, and the ferrous oxidation-xylenol orange method was used to assess the susceptibility of tissues to oxidation. Our results indicate that FA composition of rabbit and chicken meat, liver and plasma was scarcely altered by the addition of recovered frying oils to feed. Differences were encountered in the FA composition between species, which might be attributed mainly to differences in the FA digestion, absorption and metabolism between species, and to some physiological dietary factors (i.e. coprophagy in rabbits that involves fermentation with FA structure modification). The α-tocopherol (αT) content of tissues was reduced in response to the lower αT content in the recovered frying oil. Differences in the content of other tocols were encountered between chickens and rabbits, which might be attributable to the different tocol composition of their feeds, as well as to species differences in the digestion and metabolism of tocols. Tissue oxidation and susceptibility to oxidation were in general low and were not greatly affected by the degree of oxidation of the oil added to the feeds. The relative content of polyunsaturated fatty acids/αT in these types of samples would explain the differences observed between species in the susceptibility of each tissue to oxidation. According to our results, oils recovered from the frying industry could be useful for feed uses.
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We supplemented diets with a-tocopheryl acetate (100 mg/kg) and replaced beef tallow (BT) in feeds with increasing doses of n-6- or n-3-rich vegetable fat sources (linseed and sunflower oil), and studied the effects on the fatty acid (FA) composition, the a-tocopherol (aT) content and the oxidative stability of rabbit plasma and liver. These effects were compared with those observed in a previous study in rabbit meat. As in meat, the content of saturated, monounsaturated and trans FA in plasma and liver mainly reflected feed FA profile, except stearic acid in liver, which increased as feeds contained higher doses of vegetable fat, which could be related to an inhibition of the activity of the stearoyl-CoA-desaturase. As linseed oil increased in feeds, the n-6/n-3 FA ratio was decreased in plasma and liver as a result of the incorporation of FA from diets and also, due to the different performance and selectivity of desaturase enzymes. However, an increase in the dose of vegetable fat in feeds led to a significant reduction in the aT content of plasma and liver, which was greater when the fat source was linseed oil. Increasing the dose of vegetable fat in feeds also led to an increase in the susceptibility to oxidation (lipid hydroperoxide (LHP) value) of rabbit plasma, liver and meat and on the thiobarbituric acid (TBA) values of meat. Although the dietary supplementation with a-tocopheryl acetate increased the aT content in plasma and liver, it did not modify significantly their TBA or LHP values. In meat however, both TBA and LHP values were reduced by the dietary supplementation with a-tocopheryl acetate. The plasma aT content reflected the aT content in tissues, and correlated negatively with tissue oxidability. From the studied diets, those containing 1.5% linseed oil plus 1.5% BT and 100 mg of a-tocopheryl acetate/kg most improved the FA composition and the oxidative stability of rabbit tissues.
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Study on the composition and distribution of Phytobenthic Assemblages of Addaia Bay (Menorca, Western Mediterranean)
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OBJECTIVES: To test the validity of a simple, rapid, field-adapted, portable hand-held impedancemeter (HHI) for the estimation of lean body mass (LBM) and percentage body fat (%BF) in African women, and to develop specific predictive equations. DESIGN: Cross-sectional observational study. SETTINGS: Dakar, the capital city of Senegal, West Africa. SUBJECTS: A total sample of 146 women volunteered. Their mean age was of 31.0 y (s.d. 9.1), weight 60.9 kg (s.d. 13.1) and BMI 22.6 kg/m(2) (s.d. 4.5). METHODS: Body composition values estimated by HHI were compared to those measured by whole body densitometry performed by air displacement plethysmography (ADP). The specific density of LBM in black subjects was taken into account for the calculation of %BF from body density. RESULTS: : Estimations from HHI showed a large bias (mean difference) of 5.6 kg LBM (P<10(-4)) and -8.8 %BF (P<10(-4)) and errors (s.d. of the bias) of 2.6 kg LBM and 3.7 %BF. In order to correct for the bias, specific predictive equations were developed. With the HHI result as a single predictor, error values were of 1.9 kg LBM and 3.7 %BF in the prediction group (n=100), and of 2.2 kg LBM and 3.6 %BF in the cross-validation group (n=46). Addition of anthropometrical predictors was not necessary. CONCLUSIONS: The HHI analyser significantly overestimated LBM and underestimated %BF in African women. After correction for the bias, the body compartments could easily be estimated in African women by using the HHI result in an appropriate prediction equation with a good precision. It remains to be seen whether a combination of arm and leg impedancemetry in order to take into account lower limbs would further improve the prediction of body composition in Africans.
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The addition of some fat co- and by-products to feeds is usual nowadays; however, the regulations of their use are not always clear and vary between countries. For instance, the use of recycled cooking oils is not allowed in the European Union, but they are used in other countries. However, oils recovered from industrial frying processes could show satisfactory quality for this purpose. Here we studied the effects of including oils recovered from the frying industry in rabbit and chicken feeds (at 30 and 60 g/kg, respectively) on the fatty acid (FA) and tocol (tocopherol1tocotrienol) compositon of meat, liver and plasma, and on their oxidative stability. Three dietary treatments (replicated eight times) were compared: fresh non-used oil (LOX); oil discarded from the frying industry, having a high content of secondary oxidation compounds (HOX); and an intermediate level (MOX) obtained by mixing 50 : 50 of LOX and HOX. The FA composition of oil diets and tissues was assessed by GC, their tocol content by HPLC, the thiobarbituric acid value was used to assess tissue oxidation status, and the ferrous oxidation-xylenol orange method was used to assess the susceptibility of tissues to oxidation. Our results indicate that FA composition of rabbit and chicken meat, liver and plasma was scarcely altered by the addition of recovered frying oils to feed. Differences were encountered in the FA composition between species, which might be attributed mainly to differences in the FA digestion, absorption and metabolism between species, and to some physiological dietary factors (i.e. coprophagy in rabbits that involves fermentation with FA structure modification). The a-tocopherol (aT) content of tissues was reduced in response to the lower aT content in the recovered frying oil. Differences in the content of other tocols were encountered between chickens and rabbits, which might be attributable to the different tocol composition of their feeds, as well as to species differences in the digestion and metabolism of tocols. Tissue oxidation and susceptibility to oxidation were in general low and were not greatly affected by the degree of oxidation of the oil added to the feeds. The relative content of polyunsaturated fatty acids/aT in these types of samples would explain the differences observed between species in the susceptibility of each tissue to oxidation. According to our results, oils recovered from the frying industry could be useful for feed uses.
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This paper presents a validation study on statistical nonsupervised brain tissue classification techniques in magnetic resonance (MR) images. Several image models assuming different hypotheses regarding the intensity distribution model, the spatial model and the number of classes are assessed. The methods are tested on simulated data for which the classification ground truth is known. Different noise and intensity nonuniformities are added to simulate real imaging conditions. No enhancement of the image quality is considered either before or during the classification process. This way, the accuracy of the methods and their robustness against image artifacts are tested. Classification is also performed on real data where a quantitative validation compares the methods' results with an estimated ground truth from manual segmentations by experts. Validity of the various classification methods in the labeling of the image as well as in the tissue volume is estimated with different local and global measures. Results demonstrate that methods relying on both intensity and spatial information are more robust to noise and field inhomogeneities. We also demonstrate that partial volume is not perfectly modeled, even though methods that account for mixture classes outperform methods that only consider pure Gaussian classes. Finally, we show that simulated data results can also be extended to real data.
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This booklet is a compilation of notes taken during motor grader operators workshops held at some 20 different locations throughout Iowa during the last two years. It is also the advice of 16 experienced motor grader operators and maintenance foremen (from 14 different counties around Iowa), who serve as instructors and assistant instructors at the "MoGo" workshops. The instructors have all said that they learn as much from the operators who attend the workshops as they impart. Motor grader operators from throughout Iowa have shown us new, innovative and better ways of maintaining gravel roads. This booklet is an attempt to pass on some of these "tips" that we have gathered from Iowa operators. It will need to be revised, corrected, and added to based on the advice we get from you, the operators who do the work here in Iowa.