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41.
Nitrogen transformations occurring in ten soils fertilized with urea were determined during incubation in the laboratory for four weeks. Urea was applied at one rate, but with different placement methods. Urea was applied in solution, as prills with a 1 cm grid spacing and as prills with no spacing. Unfertilized soils and soils amended with KNO3 solution were included as controls.Nitrite accumulated in the majority of soils treated with urea, and the maximum nitrite concentration measured was directly related to initial soil pH. Cumulative gaseous N losses as percentages of applied N were: NH3, 0-59.6; N2, 0-4.9; N2O, 0-9.9; KMnO4-N, 0-1.3; CH3ONO, 0-<0.1. No gaseous N evolution was detected in control treatments. Gaseous N losses were correlated with soil pH (NH3) maximum NO
2
-
concentration (N2, N2O, KMnO4-N) and organic C content (N2, N2O). Fertilizer placement effects were generally not significant and were small in comparison with differences between soils.
Resumo Foram determinadas, durante incubação em laboratório por quatro semanas, as transformações do nitrogênio ocorridas em dez solos fertilizados com uréia. A uréia foi aplicada a um só nivel, mas com diferentes métodos de aplicação: em solução e em grânulos com 1 cm de espaçamento de grade e em grânulos sem espaçamento. Solos não fertilizados e solos corrigidos com solução de KNO3 foram incluidos como controles.O nitrito acumulado na maioria dos solos tratados com uréia e a concentração máxima de nitrito medido foram diretamente relacionados ao pH inicial do solo. As perdas cumulativas de N gasoso tomadas em percentagens de N aplicado foram: NH3, 0-59.6; N2, 0-4.9; N2O; 0-9.9; KMnO4-N, 0-1.3; CH3ONO, 0-<0.1. Não foi detectada liberação de N gasoso nos tratamentos de controle. As perdas de N gasoso foram relacionadas com o pH do solo (NH3), concentração máxima de NO 2 - (N2, N2O, KMnO4-N) e teor de C orgânico (N2, N2O). Efeitos da aplicação de fertilizante não foram de um modo geral significativos e foram pequenos em comparação com as diferenças entre os solos.相似文献
42.
André Lourenço Hugo Plácido da Silva Carlos Carreiras Ana Priscila Alves Ana L. N. Fred 《Multimedia Tools and Applications》2014,70(1):433-460
With the advent of wearable sensing and mobile technologies, biosignals have seen an increasingly growing number of application areas, leading to the collection of large volumes of data. One of the difficulties in dealing with these data sets, and in the development of automated machine learning systems which use them as input, is the lack of reliable ground truth information. In this paper we present a new web-based platform for visualization, retrieval and annotation of biosignals by non-technical users, aimed at improving the process of ground truth collection for biomedical applications. Moreover, a novel extendable and scalable data representation model and persistency framework is presented. The results of the experimental evaluation with possible users has further confirmed the potential of the presented framework. 相似文献
43.
L B Zago S M Friedman N H Slobodianik M L de Portela M E Río J C Sanahuja 《Archivos latinoamericanos de nutrición》1983,33(4):802-813
In order to analyze the interrelationships between free erythrocyte protoporphyrins and the usual iron intake in adult students, biochemical, and hematological values, and dietary daily intake, obtained using the recall method during seven days, were studied. Hematocrit (Hto.), hemoglobin (Hb) and free erythrocyte protoporphyrins (FEP) were determined in a group of 145 female university students, healthy according to the standard parameters of the Buenos Aires University Health Department. Mean iron intake was 23.0 +/- 1.5 mg per day, about 44% being provided by animal sources; 74.5% of the population was within the recommended daily intake according to FAO/WHO; only 0.7% of the population did not cover protein requirements while 35% did not cover energy needs. Hto. and Hb were below normal levels in 7.8% of the population when compared with standards according to ICNND. To obtain information about normal values to FEP, expressed as microgram/100 ml red cells (FEP% r.c.) and FEP/Hb ratio, the group of students with adequate intake of energy and proteins who had normal values for Hb and Hto. was selected. This group, including 94 women, had a mean FEP% r.c. of 15.71 +/- 7.26 and a mean FEP/Hb ratio of 0.44 +/- 0.21. There was observed an inverse correlation between FEP% r.c. and FEP/Hb with total iron intake (r = 0.80 and r = 0.78, respectively) and between FEP% r.c. and Hb concentration (r = 0.81). These results confirm the usefulness of the free erythrocyte protoporphyrins determination as a good index of iron stores and usual intake of this population. 相似文献
44.
The main purpose of the present study was to determine the qualitative and quantiative effect of various infectious epsiodes on the blood serum levels of retinol and retinol-binding protein (RBP). Twenty-four children and 30 adult subjects were studied. The infections studied included chickenpox (n = 7); bronchitis (n = 9) upper respiratory infection (n = 30); tonsillitis (n = 2); diarrhea (n = 2) and one case each of: febrile stomatitis, nonspecific gastrointestinal alteration, urinary infection and shigellosis. In addition to retinol and RBP, the study determined changes in serum carotene, proteins, albumin and globulins. The results clearly demonstrate the marked depressing effect of infections on serum retinol, with a magnitude which in many cases reached more than 20 micrograms/dl, and in others more than 30 micrograms/dl. The RBP levels were significantly correlated with retinol, decreasing proportionally with infection. Serum albumin also decreased in most instances; and the globulin levels of the children, but not of the adults, were significantly higher during the infections. Carotene did not show important variations. The effects were more intense when fever accompanied the infectious episodes. These results are considered of great public health significance, in view of the large majorities, mainly children, who ordinarily subsist with very low serum retinol levels in the underdeveloped regions of the world. As infections attack these underpriviledged children, their serum retinol and RBP levels will likely drop a magnitude similar to that observed in the subjects of this study. They may then reach even more critically deficient retinol levels and be in serious danger of developing a severe acute state of clinical vitamin A deficiency. 相似文献
45.
Raul C. Maranhão Thais B. Cesar Suzana R. Pedroso-Mariani Mario H. Hirata Carlos H. Mesquita 《Lipids》1993,28(8):691-696
A protein-free microemulsion (LDE) with a lipid composition resembling that of low-density lipoprotein (LDL) was used in metabolic
studies in rats to compare LDE with the native lipoprotein. LDE labeled with radioactive lipids was injected into the bloodstream
of male Wistar rats, and plasma kinetics of the labeled lipids were followed on plasma samples collected at regular intervals
for 12 h after injection. The 24-h LDE uptake by different tissues was also measured in tissue samples excised after the animals
had been sacrificed. We found that LDE plasma kinetics were similar to those described for native LDL [fractional clearance
rate (FCR) of cholesteryl ester, 0.42±0.11 h−1]. The major site for LDE uptake was the liver, and the tissue distribution of the LDE injected radioactivity was as one would
expect for LDL. To test whether LDE was taken up by the specific LDL receptors, the LDE emulsion was injected into rats treated
with 17α-ethinylestradiol, which is known to increase the activity of these receptors; as expected, removal of LDE from the
bloodstream increased (FCR=0.90±0.35 h−1). On the other hand, saturation of the receptors that remove remnants by prior infusion of massive amounts of lymph chylomicrons
did not change LDE plasma kinetics. These results indicate that LDE is cleared from plasma by B,E receptors and not by the
E receptors that remove remnants. Incorporation of free cholesterol into LDE increased LDE plasma clearance. Incubation studies
also showed that LDE incorporates a variety of apolipoproteins, including apo E, a ligand for recognition of lipoproteins
by specific receptors. Our data suggest that LDE can be a useful tool to test LDL metabolism and B,E receptor function. 相似文献
46.
Male and female weanling rats that were born to dams fed a diet low in linolenic acid received diets of 15% lipids by weight
containing 45% elaidic acid (as trielaidin) and 8.5% or 0.1% linolenic acid for 10 weeks. Four other groups, in which palmitic
or oleic acid replaced elaidic acid in the diet, served as controls. The fatty acid profiles of several lipid classes were
determined in adipose tissue, adrenals, testes, heart and brain. Elaidic acid was incorporated into tissue lipids in varying
degrees, depending on the organ and on the lipid class. Feeding elaidic acid induced no changes in the polyunsaturated fatty
acid (PUFA) profiles of testes lipids but resulted in definite modifications of the PUFA patterns of heart phosphatidylcholine
(PC) and phosphatidylethanolamine (PE). In linolenic acid-deprived rats, arachidonic acid was decreased in PC and linoleic
acid was increased in both PC and PE; 22∶5n−6 was strongly depressed in both PC and PE. In linolenic acid-fed rats, 22∶6n−3
was decreased in PC and PE. These changes, on the whole, were more evident in females, and some also were observed in adrenal
cholesteryl esters but only slightly in brain phospholipids. the apparent inhibition of the biosynthesis of PUFA induced by
dietary elaidic acid appeared to be complex and of greater intensity in the n−6 fatty acid series than in their n−3 homologues. 相似文献
47.
Abraho Silvia Insfran Emilio Sluters Arthur Vanderdonckt Jean 《Software and Systems Modeling》2021,20(5):1335-1349
Software and Systems Modeling - Adapting the user interface of a software system to the requirements of the context of use continues to be a major challenge, particularly when users become more... 相似文献
48.
Lourenço André Rota Bulò Samuel Rebagliati Nicola Fred Ana L. N. Figueiredo Mário A. T. Pelillo Marcello 《Machine Learning》2015,98(1-2):331-357
Machine Learning - Clustering ensemble methods produce a consensus partition of a set of data points by combining the results of a collection of base clustering algorithms. In the evidence... 相似文献
49.
50.
A depth-based classification method underlain by a remote concentration measure for processing asymmetric data is developed and investigated. The motivation for the construction of the method was the inefficient use of affine invariant classifiers in combination with depth functions vanishing outside the convex hull of data. The idea of the proposed method is to map a remote space using a remote concentration measure, the Stahel–Donoho remoteness measure, and a corrected remoteness measure. 相似文献