9 resultados para Bessel and Besov Spaces

em Biblioteca Digital da Produção Intelectual da Universidade de São Paulo


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Structural differences such as abnormalities, damage and free spaces in seeds may affect germination. The aim of this study was to study the relationship between eggplant seed morphology and seed germination. Ten seed lots of the eggplant cultivar Embu were evaluated by X-ray image analysis and the germination test. Seed image analysis was performed by Image Pro Plus® software and the whole seed area and free space between the embryo and endosperm were measured. The internal seed area filled by the embryo and endosperm was calculated from the difference between the whole seed and free space areas. Based on these results and visual seed analysis, seeds were classified into three categories and information on germination was obtained for each one. X-ray image analysis provides a perfect view of the internal seed parts and for seed morphology studies. An increase in seed area filled by the endosperm and embryo does not improve seed germination. Mechanical seed damage and deteriorated tissues can adversely affect seed germination.

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The scope of this paper is to validate proposals used to qualify hospital food by the Brazilian scientific community. An electronic questionnaire was applied to clinical nutrition professionals registered on the Lattes Platform (Brazilian database of institutions and researchers' curricula in the areas of Science and Technology). The questionnaire incorporated a Likert scale and had spaces for comments. The themes dealt with patient participation, the nutritional and sensory quality of hospital diets, and planning and goals of the Hospital Food and Nutrition Service (HFNS). The questionnaire also asked for the top five priorities for a HFNS. Proposals with total or partial adherence equal to or greater than 70% were considered to be approved. All proposals had total adherence equal to or greater than 70%. The proposal that had minimal adherence (70%) was the one that proposed that nutritional intervention must be arranged by mutual agreement with the patient. The proposal that had maximal adherence (93%) was the one advocating that there must be statistical control on diets prescribed by the HFNS. The most cited priorities referred to infrastructure and training of human resources (40%), the quality of hospital food (27%) and the nutritional status of the patient.

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Smilax L. in Brazil is represented by 32 taxa and it is a taxonomically difficult genus because the plants are dioecious and show wide phenotypic variation. The analysis and use of leaf anatomy characters is recognized as a frequently successful taxonomic method to distinguish between individual taxon, when floral material is absent or minute differences in flowers and foliage exist such as in Smilax. The aim of this study was to characterize the anatomical features of the aerial organs in Smilax syphilitica collected from the Atlantic Rainforest, in Santa Teresa-ES and the Smilax aff syphilitica from the Amazon Rainforest, in Manaus, Brazil. For this, a total of three samples of Smilax were collected per site. Sample leaves and stems were fixed with FAA 50, embedded in historesin, sectioned on a rotary microtome, stained and mounted in synthetic resin. Additionally, histochemical tests were performed and cuticle ornamentation was analyzed with standard scanning electron microscopy. S. syphilitica and S. aff syphilitica differed in cuticle ornamentation, epidermal cell arrangement and wall thickness, stomata type and orientation, calcium oxalate crystal type, and position of stem thorns. Leaf blades of S. syphilitica from the Amazon Rainforest have a network of rounded ridges on both sides, while in S. aff syphilitica, these ridges are parallel and the spaces between them are filled with numerous membranous platelets. Viewed from the front, the epidermal cells of S. syphilitica have sinuous walls (even more pronounced in samples from the Amazon); while in S. aff syphilitica, these cells are also sinuous but elongated in the cross-section of the blade and arranged in parallel. Stomata of S. syphilitica are paracytic, whereas in S. aff syphilitica, are both paracytic and anisocytic, and their polar axes are directed towards the mid-vein. Calcium oxalate crystals in S. syphilitica are prisms, whereas in S. aff syphilitica, crystal sand. Thorns occur in nodes and internodes in S. syphilitica but only in internodes in S. aff syphilitica. These features have proven to be of diagnostic value and may support a separation into two species, but future studies are needed to confirm that S. aff syphilitica is indeed a new taxon. Rev. Biol. Trop. 60(3): 1137-1148. Epub 2012 September 01.

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This paper studies the asymptotic optimality of discrete-time Markov decision processes (MDPs) with general state space and action space and having weak and strong interactions. By using a similar approach as developed by Liu, Zhang, and Yin [Appl. Math. Optim., 44 (2001), pp. 105-129], the idea in this paper is to consider an MDP with general state and action spaces and to reduce the dimension of the state space by considering an averaged model. This formulation is often described by introducing a small parameter epsilon > 0 in the definition of the transition kernel, leading to a singularly perturbed Markov model with two time scales. Our objective is twofold. First it is shown that the value function of the control problem for the perturbed system converges to the value function of a limit averaged control problem as epsilon goes to zero. In the second part of the paper, it is proved that a feedback control policy for the original control problem defined by using an optimal feedback policy for the limit problem is asymptotically optimal. Our work extends existing results of the literature in the following two directions: the underlying MDP is defined on general state and action spaces and we do not impose strong conditions on the recurrence structure of the MDP such as Doeblin's condition.

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In this paper a space X is pseudocompact if it is Tychonoff and every real-valued continuous function on X is bounded. We obtain conditions under which a Tychonoff space is maximal pseudocompact and study conditions under which a regular space is maximal R-closed.

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We extend and provide a vector-valued version of some results of C. Samuel about the geometric relations between the spaces of nuclear operators N(E, F) and spaces of compact operators K(E, F), where E and F are Banach spaces C(K) of all continuous functions defined on the countable compact metric spaces K equipped with the supremum norm. First we continue Samuel's work by proving that N(C(K-1), C(K-2)) contains no subspace isomorphic to K(C(K-3), C(K-4)) whenever K-1, K-2, K-3 and K-4 are arbitrary infinite countable compact metric spaces. Then we show that it is relatively consistent with ZFC that the above result and the main results of Samuel can be extended to C(K-1, X), C(K-2,Y), C(K-3, X) and C(K-4, Y) spaces, where K-1, K-2, K-3 and K-4 are arbitrary infinite totally ordered compact spaces; X comprises certain Banach spaces such that X* are isomorphic to subspaces of l(1); and Y comprises arbitrary subspaces of l(p), with 1 < p < infinity. Our results cover the cases of some non-classical Banach spaces X constructed by Alspach, by Alspach and Benyamini, by Benyamini and Lindenstrauss, by Bourgain and Delbaen and also by Argyros and Haydon.

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This paper studies the average control problem of discrete-time Markov Decision Processes (MDPs for short) with general state space, Feller transition probabilities, and possibly non-compact control constraint sets A(x). Two hypotheses are considered: either the cost function c is strictly unbounded or the multifunctions A(r)(x) = {a is an element of A(x) : c(x, a) <= r} are upper-semicontinuous and compact-valued for each real r. For these two cases we provide new results for the existence of a solution to the average-cost optimality equality and inequality using the vanishing discount approach. We also study the convergence of the policy iteration approach under these conditions. It should be pointed out that we do not make any assumptions regarding the convergence and the continuity of the limit function generated by the sequence of relative difference of the alpha-discounted value functions and the Poisson equations as often encountered in the literature. (C) 2012 Elsevier Inc. All rights reserved.

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We propose an integral formulation of the equations of motion of a large class of field theories which leads in a quite natural and direct way to the construction of conservation laws. The approach is based on generalized non-abelian Stokes theorems for p-form connections, and its appropriate mathematical language is that of loop spaces. The equations of motion are written as the equality of a hyper-volume ordered integral to a hyper-surface ordered integral on the border of that hyper-volume. The approach applies to integrable field theories in (1 + 1) dimensions, Chern-Simons theories in (2 + 1) dimensions, and non-abelian gauge theories in (2 + 1) and (3 + 1) dimensions. The results presented in this paper are relevant for the understanding of global properties of those theories. As a special byproduct we solve a long standing problem in (3 + 1)-dimensional Yang-Mills theory, namely the construction of conserved charges, valid for any solution, which are invariant under arbitrary gauge transformations. (C) 2012 Elsevier B.V. All rights reserved.

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This article is a continuation of our previous work [5], where we formulated general existence theorems for pullback exponential attractors for asymptotically compact evolution processes in Banach spaces and discussed its implications in the autonomous case. We now study properties of the attractors and use our theoretical results to prove the existence of pullback exponential attractors in two examples, where previous results do not apply.