Showing papers by "State University of Campinas published in 1998"

Transesterification of vegetable oils: a review

Abstract: The transesterification of vegetable oils with methanol as well as the main uses of the fatty acid methyl esters are reviewed. The general aspects of this process and the applicability of different types of catalysts (acids, alkaline metal hydroxides, alkoxides and carbonates, enzymes and non-ionic bases, such as amines, amidines, guanidines and triamino(imino)phosphoranes) are described. Special attention is given to guanidines, which can be easily heterogenized on organic polymers. However, the anchored catalysts show leaching problems. New strategies to obtain non-leaching guanidine-containing catalysts are proposed. Finally, several applications of fatty acid esters, obtained by transesterification of vegetable oils, are described.

An introduction to fuzzy sets : analysis and design

Abstract: Part 1 Fundamentals of fuzzy sets: basic notions and concepts of fuzzy sets - set membership and fuzzy sets, basic definitions of a fuzzy set, types of membership functions, characteristics of a fuzzy set, basic relationships between fuzzy sets - equality and inclusion, fuzzy sets and sets - the representation theorem, the extension principles, membership function determination, generalizations of fuzzy sets, chapter summary, problems, references fuzzy set operations - set theory operations and their properties, triangular norms, aggregation operations on fuzzy sets, sensitivity of fuzzy sets operators, negations, comparison operations on fuzzy sets, chapter summary, problems, references information-based characterization of fuzzy sets -entropy measures of fuzziness, energy measures of fuzziness, specificity of a fuzzy set, frames of cognition, information encoding and decoding using linguistic landmarks, decoding mechanisms for pointwise data, decoding using membership functions of the linguistic terms of the codebook, general possibility-necessity decoding, distance between fuzzy sets based on their internal, linguistic representation, chapter summary, problems, references fuzzy relations and their calculus -relations and fuzzy relations, operations on fuzzy relations, compositions of fuzzy relations, projections and cylindric extensions of fuzzy relations, binary fuzzy relations, some classes of fuzzy relations, fuzzy-relational equations, estimation and inverse problem in fuzzy relational equations, solving fuzzy-relational equations with the sup-t composition, solutions to dual fuzzy-relational equations, adjoint fuzzy-relational equations, generaliations of fuzzy relational equations, approximate solutions to fuzzy-relational equations, chapter summary, problems, references fuzzy numbers - defining fuzzy numbers, interval analysis and fuzzy numbers, computing with fuzzy numbers, triangular fuzzy numbers and basic operations, general formulas for LR fuzzy numbers, accumulation of fuzziness in computing with fuzzy numbers, inverse problem in computation with fuzzy numbers, fuzzy numbers and approximate operations, chapter summary, problems, references fuzzy modelling - fuzzy models - beyond numerical computations, main phases of system modelling, fundamental design objectives in system modelling, general topology of fuzzy models, compatibility of encoding and decoding modules, classes of fuzzy models, verification and validation of fuzzy models, chapter summary, problems, references. Part 3 Problem solving with fuzzy sets: methodology -analysis and design, fuzzy controllers and fuzzy control, mathematical programming and fuzzy optimization, chapter summary, problems, references case studies - traffic intersection control, distributed traffic control, elevator group control, induction motor control, communication network planning, neurocomputation in fault diagnosis of dynamic systems, multicommodity transportation planning in railways.

Heterogeneous Catalysts for Liquid-Phase Oxidations: Philosophers' Stones or Trojan Horses?

Abstract: Introduction In the early seventies one of us1 was involved in the development of the heterogeneous Ti(IV)/SiO2 catalyst which forms the basis of the Shell process for the epoxidation of propylene with ethylbenzene hydroperoxide (reaction 1).2 Halcon3 and ARCO4,5 workers had previously found, independently, that soluble compounds of early transition metals, e.g., Mo, W, Ti, and V, catalyze reaction 1. The mechanism of catalysis involves withdrawal of electrons from a coordinated alkylperoxo moiety, thereby increasing the electrophilic character of the peroxidic oxygens, i.e., the metal ion acts as a Lewis acid. Hence, effective catalysts are both a strong Lewis acid and a weak oxidant in their highest oxidation state. The latter criterion is necessary in order to minimize competing one-electron oxidation of the ROO ligand leading to homolytic decomposition of ROOH (see Scheme 1). These criteria are best met by molybdenum(VI), and soluble molybdenum compounds exhibit the best combination of activity and selectivity.6,7 Soluble titanium(IV) compounds, on the other hand, are rather mediocre catalysts for reaction 1. In contrast, Ti(IV)/SiO2 exhibits selectivities comparable to homogeneous molybdenum and (for a heterogeneous catalyst) high activities.8 The superior catalytic activity of Ti(IV)/SiO2 was attributed to both an increase in Lewis acidity of the Ti(IV), owing to electron withdrawal by silanoxy ligands, and to site isolation of discrete Ti(IV) centers in the silica lattice preventing oligomerization to unreactive μ-oxo species (which readily occurs with soluble Ti(IV) compounds). Furthermore, it was demonstrated that only the combination of titanium(IV) with silica affords a stable heterogeneous catalyst; all other combinations, e.g., Mo(VI), W(VI), V(V), etc., on silica, gave rapid leaching of the metal ion. One property which soluble Ti(IV) compounds and Ti(IV)/SiO2 share is a marked sensitivity toward deactivation by strongly coordinating ligands, especially water.9 For this reason Ti(IV)/ SiO2 is an ineffective catalyst for epoxidations with aqueous hydrogen peroxide. Hence the appearance in the mid-eighties of Enichem patents10 describing the remarkable catalytic activity of titanium(IV) silicalite (generally known as TS-1) in, inter alia, the selective epoxidation of olefins under very mild conditions with 30% aqueous hydrogen peroxide (Figure 1) was greeted with some scepticism. Thus, two materials, Ti(IV)/SiO2 and TS-1, having roughly the same elemental composition, i.e., 2% Ti in SiO2, exhibited totally different catalytic properties. Initial attempts by various groups to reproduce the Enichem results were largely unsuccessful. However, once it became clear that certain parameters in the synthesis

Geographic Distribution of the 20210 G to A Prothrombin Variant

Abstract: A variant in prothrombin (clotting factor II), a G to A transition at nucleotide position 20210, has recently been shown to be associated with the prothrombin plasma levels and the risk of both venous and arterial thrombosis. The purpose of this study was to investigate the prevalence of carriership of this mutation in various populations. We combined data from 11 centres in nine countries, where tests for this mutation had been performed in groups representing the general population. We calculated an overall prevalence estimate, by a precision-weighted method, and, since the distribution of the prevalences did not appear homogeneous, by an unweighted average of the prevalences. We examined differences in the prevalences by geographical location and ethnic background as a possible explanation for the heterogeneity. Among a total of 5527 individuals who had been tested, 111 heterozygous carriers of the 20210A mutation were found. The prevalence estimates varied from 0.7 to 4.0 between the centres. The overall prevalence estimate was 2.0 percent (CI95 1.4-2.6%). The variation around the summary estimate appeared more than was expected by chance alone, and this heterogeneity could be explained by geographic differences. In southern Europe, the prevalence was 3.0 percent (CI95 2.3 to 3.7%), nearly twice as high as the prevalence in northern Europe (1.7%, CI95 1.3 to 2.2%). The prothrombin variant appeared very rare in individuals from Asian and African descent. The 20210A prothrombin variant is a common abnormality, with a prevalence of carriership between one and four percent. It is more common in southern than in northern Europe. Since this distribution within Europe is very different to that of another prothrombotic mutation (factor V Leiden or factor V R506Q), founder effects are the most likely explanation for the geographical distribution of both mutations.

Origem e evolução da Serra do Mar

Abstract: The origin of the subparallel mountain systems which compose the coastal Serra do Mar and the inland Serra da Mantiqueira is related to the Upper Cretaceous. These features - distributed along a quite singular continental atlantic border - nave a complex evolution arising controversial questions. The answers to these problems are mainly dependentto the dating of the Japi erosional surface and other younger ones, a study still faced by the small amount of detailed-scale surveys. The scarp domains covered by dense vegetation often impose difficult trail access. Nevertheless, the present knowledge stage allows us to admit that during Tertiary the evolution of the local relief has affected into a considerable extent the synchronic oceanic phase sediments of the Santos Basin. There is a lot of evidence and proofs that the Serra do Mar has been developed from a very different geographical position as compared to the existing one. The hypothesis supported by the present authors is a long-term scarp retreat from southeast to northwest due to erosional processes approximately starting at the Santos fault line in the present continental platform.

Towards historical R-trees

Abstract: R-trees are the "de facto" reference structures for indexing spatial data, namely the minumum bounding rectangles (MBRs) of spatial objects. However, R-trees, as currently known, do not support the evohition of such MBRs. Whenever an M B R evolves, its new version replaces the old one, which is therefore lost. Thus, an R-tree always shows the current state of the data set, not allowing the user to query the spatial database with respect to past states. In this paper we extend the R-tree in such a way that old states are preserved, allowing the user to query them. The proposed approach does not duplicate nodes which were not modified, thus saving considerable storage space. On the other hand, the query processing time does not depend on the number of past states stored. 1 I N T R O O U C T i O N Managing multidimensional data is needed in many application domains, e.g., spatial databases and geographical information systems [13]. In particular, indexing spatial data. is of foremost importance in many application domains, and indeed such an issue has been quite well researched. Samet [13] and Gaede and G/inther [4] present excellent surveys on the area. However, it is hardly argueable that an structure has been more cited and used as a reference than the R-tree [5]. The R+-t ree [14] and the R*-tree [I] are well known R-tree derivatives, where the R°t ree has been shown to be quite efficient. Recently, the Hilbert R-tree [7] and the STRtree [9] have been shown to have bet ter "packing" capabilities. This is specially useful for sets of data which are not very dynamic in nature. With the exception of the R+-tree, all have the same basic structure. K-dimensional spatial objects are modeled by their Minimum Bounding Rectangles (MBRs) we assume, without loss of generality, that K = 2. Subsets of the indexed MBRs are organized into overlapping subspaces, using a tree hierarchy. They all differ in the way "Also an invited lecturer at Institute of Computing of the State University of Campinas (marioQdcc.unicarnp.br). '~Supported by CAPES. Alternative emaih jeffsilva~writeme.com Permission to make digital/hard copy of all or part of this work for personal or classroom use is granted without Ii~e provided that copies are not made or distributed lbr profit or commercial advantage, the copyright notice, the title of the publication and its date appear, and notice is given that copying is by permission of ACM. Inc. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a tee. © 1998 ACM 0-89791-969-6/98/0002 3.50 235 the tree nodes are split (when overflown) and /o r MBRs are assigned to subspaces (i.e., nodes in tree). | n this stage of our research we assume an R-tree has already been built by using algori thms from any of the Rtree derivatives, but the R +-tree. Regardless of how it was built, we refer to such an s tructure as an R-tree, and we assume it obeys the following conditions [51 (where a hyperrectangle is an MBR): • Every leaf (non-leaf) node contain between m and M index records (children) unless it is the root; • For each index record (I, Tid) in a leaf node, I is the smallest hyper-rectangle that spatially contains the object represented by the indicated tuple Tid; • For each entry (I, Cid) in a non-leaf node, I is the smallest hyper-rectangle that spatially contains the hyperrectangles in the child node Cid; • The root node has at least two children tmless it is a leaf; • All leaves appear on the same level. For simplicity, and proof-of-concept, we base our algorithms for insertion, deletion and updating on those by Gutmann [5]. MBRs can model objects which vary with time, one trivial example is a farm which can be expanded or shmmk by selling or buying land. Similarly new ohjeet.s can begin or cease to exist. An Rt ree indexes only the current M B R for each object . Should any object evolve and have its M B R changed, the Rt ree must delete the old MBR and insert the new one (the one corresponding to the new instance of the object) . From that point on, no query will ever take into account that past instance of that part icular MBR. In other words, R-trees as currently known, allow querying only the current state of a spatial database. A trivial way to overcome such shortcoming would be to store all previous states of the R-trees. As we shall see shortly, this is not an acceptable, nor practical, solution. The problem of indexing non-spatial objects {i.e., regular tuples in a relation) over t ime has been researched by many researchers in the temporal databases community. A thorough survey can be found in [12]. However, to our knowledge no research has been published regarding the temporal izat ion of the R-tree. Tha t is exactly the kernel of our contribution. We assume the temporal a t t r ibute is t ransact ion time. Transact ion t ime interval is the t ime an object has been stored in the database [6]. Hence an M B R is considered stored in the spatial database since the t ime it is input ad infinitum, or until the point it is upda ted or deleted. This special feature prevents one of using the quite simple idea of . ~ . • • ._. . ~ . i ~ . ~ , ~ . ~ . ~ : ~ ~ . ~ • / . , . : : considering time as another spatial dimension, thus using the t ( + 1 dimensional space to index MBRs varying over time. The problem is that the current MBR versions would have one of its "sides" being extended continously (notice that the current point in time is always moving forward). Even if one could somehow manage this variable side, it would imply a large overlap ratio among the R-trees' subspaces (which does affect negatively the R-tree's performance). Hence, this paper addresses the problem of querying and maintaing current and past states of R-trees. To accomplish that the paper is organized as follows. The next Section presents an overview of the rationale behind our approach, which we call Historical R-trees. Section 3 discusses how the R-tree's algorithms need be changed to allow the realization of the Historical R-trees. We conclude in Section 4, presenting some issues which are being currently investigated and/or have potential for future research. 2 E N H A N C I N G R T R E E S W I T H T I M E The technique we propose is inspired by an idea first presented by Burton and colleagues [3, 2]. The authors proposed the use of overlapping trees to manage the evolution of text files. Later, the idea was generalized by [10] to manage temporally evolving B+-trees in general. The basic idea behind those techniques was to keep current and past states of the B +-trees by maintaing the original tree and replicating, from state to state, only the root and the branches which reflect any changes. The unchanged branches were not replicated, but rather were pointed to by the nodes in the new branch. The approach we propose is an extension of the overlapping approach originally proposed by Manolopoulos e Kapetanakis [10] for the B+-trees, to the R-trees. We call such an approach Historical R-tree (H-R-tree for short). In this paper we concentrate on managing it, rather than benchmarking it. Let us illustrate the rationale supporting the H-R-tree with the following example. Consider the initial R-tree in Figure l(a) at time TO. Suppose that at time T1 MBR 3 suffers a modification resulting in MBR 3a. Likewise MBR 8 is modified at time T2 yielding MBR 8a. The three states (at TO, T t and T2) of that particular R-tree are thus those shown in Figures l(a), (b) and (c) respectively. Note that in that particular example the subtree rooted at node B did not change at all, nevertheless it was replicated in all three states. Moreover, the subtree rooted at C (AI) did not change from TO (TI) to T1 (T2), but the whole subtree was replicated as well. It should be now clear that duplicating the whole tree at each state is rather unpractical. Let us now see how the same scenario would be handled by the H-R-tree. We assume an array, called A, indexing the time points where updates occurred. The initial R-tree must be kept full and it is pointed to by A/T0]. From TO to T I MBR 3 changes, and as such node A changes as well, after all its contents did change. This update propagates upwards until the root node. At the end only the path {R1, A, 3} needs to be updated, resulting the new path {R2, AI, 3a}. Naturally, the R-tree at T1 is composed by the subtrees rooted at A1, B and C. However, those rooted at B and C did not change at all, and thus need not be replicated. Similarly, at time T2 the R-tree rooted at R3 is composed by those subtrees roted at AI, B and C1. Again, from T1 to T2, the subtrees rooted at A1 and B did not go under any modification and as such need not be replicated. The resulting H-R-tree at time T2 is shown in Figure 2(a). Simple inspection shows that, even in a trivial example like this, the H-R-tree is much smaller than the set of tree R-trees in Figure 1. Figure 2(b) shows the logical view of the resulting R-tree at time T2, which is exactly the same one in Figure l(c). It is important to stress that querying any version of the R-tree under the H-R-structure is a matter of obtaining the correct R-tree root. Once this is done, using the array A[.],. the logical view is that of a standard R-tree, no complications are therefore added by the approach we use to keep the Rtree's history. 3 H I S T O R I C A L R T R E E S In this section we discuss in detail how to modify the R-tree's algorithms in order to realize the H-R-tree. Given the space constraints we omit certain details, which can be found in Guttman's original paper [5]. We draw particular attention to insertion and (logical) deletions of MBRs, modification of MBRs can be accomplished by deleting the old version and inserting the new one. As we argued above, querying any version of the R-tree is straightforward. The H-R-tree is a structure composed by an array A of time values, which in turn point to sev

Antimicrobial Activity of Propolis on Oral Microorganisms

Abstract: Formation of dental caries is caused by the colonization and accumulation of oral microorganisms and extracellular polysaccharides that are synthesized from sucrose by glucosyltransferase of Streptococcus mutans. The production of glucosyltransferase from oral microorganisms was attempted, and it was found that Streptococcus mutans produced highest activity of the enzyme. Ethanolic extracts of propolis (EEP) were examined whether EEP inhibit the enzyme activity and growth of the bacteria or not. All EEP from various regions in Brazil inhibited both glucosyltransferase activity and growth of S. mutans, but one of the propolis from Rio Grande do Sul (RS2) demonstrated the highest inhibition of the enzyme activity and growth of the bacteria. It was also found that propolis (RS2) contained the highest concentrations of pinocembrin and galangin.

Improved Algorithms for Elliptic Curve Arithmetic in GF(2n)

Abstract: This paper describes three contributions for efficient implementation of elliptic curve cryptosystems in GF(2n) The first is a new method for doubling an elliptic curve point, which is simpler to implement than the fastest known method, due to Schroeppel, and which favors sparse elliptic curve coefficients The second is a generalized and improved version of the Guajardo and Paar's formulas for computing repeated doubling points The third contribution consists of a new kind of projective coordinates that provides the fastest known arithmetic on elliptic curves The algorithms resulting from this new formulation lead to a running time improvement for computing a scalar multiplication of about 17% over previous projective coordinate methods

Effects of Ripening, Cultivar Differences, and Processing on the Carotenoid Composition of Mango.

Abstract: The carotenoid composition of mangoes produced in Brazil was determined by HPLC to appraise the effects of some influencing factors Total carotenoid rose from 123 to 380 μg/g in the cultivar Keitt and from 170 to 512 μg/g in the cultivar Tommy Atkins from the mature-green to the ripe stage Ripening alterations occurred principally in the major carotenoids, violaxanthin and β-carotene In the Keitt mangoes, all-trans-β-carotene, all-trans-violaxanthin, and 9-cis-violaxanthin (location of cis double bond tentative) increased from 17, 54, and 17 μg/g in the mature-green fruits to 67, 180, and 72 μg/g, respectively, in the ripe fruits In the Tommy Atkins cultivar, these carotenoids went from 20, 69, and 33 μg/g to 58, 224, and 145 μg/g, respectively, on ripening In both cultivars, the small amount of 13-cis-violaxanthin practically disappeared on ripening Geographic effects appeared to be substantial In commercially processed mango juice, violaxanthin was not detected, auroxanthin appear

Electronic structure of nitrogen-carbon alloys ( a − CN x ) determined by photoelectron spectroscopy

Abstract: The electronic structure of nitrogen-containing diamondlike films prepared by sputtering was determined by photoelectron spectroscopy. The $\mathrm{N}1s$ core-level spectra are constituted by two peaks at 400.5 and 398.2 eV associated with substitutional $\mathrm{N}{\mathrm{sp}}^{2}$ in aromatic rings and N bonded to $\mathrm{C}{\mathrm{sp}}^{3},$ respectively. On increasing N, the top of the valence band suffers profound changes. The new features are identified by a comparison of the experimental spectra with theoretically calculated density of states of nitrogen-containing graphite and ${\mathrm{C}}_{3}{\mathrm{N}}_{4}$ structures.

A Lagrangian reproducing kernel particle method for metal forming analysis

Abstract: A Meshless approach based on a Reproducing Kernel Particle Method is developed for metal forming analysis In this approach, the displacement shape functions are constructed using the reproducing kernel approximation that satisfies consistency conditions The variational equation of materials with loading-path dependent behavior and contact conditions is formulated with reference to the current configuration A Lagrangian kernel function, and its corresponding reproducing kernel shape function, are constructed using material coordinates for the Lagrangian discretization of the variational equation The spatial derivatives of the Lagrangian reproducing kernel shape functions involved in the stress computation of path-dependent materials are performed by an inverse mapping that requires the inversion of the deformation gradient A collocation formulation is used in the discretization of the boundary integral of the contact constraint equations formulated by a penalty method By the use of a transformation method, the contact constraints are imposed directly on the contact nodes, and consequently the contact forces and their associated stiffness matrices are formulated at the nodal coordinate Numerical examples are given to verify the accuracy of the proposed meshless method for metal forming analysis

Transmission system expansion planning by an extended genetic algorithm

Abstract: The paper presents an extended genetic algorithm for solving the optimal transmission network expansion planning problem. Two main improvements have been introduced in the genetic algorithm: (a) initial population obtained by conventional optimisation based methods; (b) mutation approach inspired in the simulated annealing technique. The proposed method is general in the sense that it does not assume any particular property of the problem being solved, such as linearity or convexity. Excellent performance is reported in the test results section of the paper for a difficult large-scale real-life problem: a substantial reduction in investment costs has been obtained with regard to previous solutions obtained via conventional optimisation methods and simulated annealing algorithms; statistical comparison procedures have been employed in benchmarking different versions of the genetic algorithm and simulated annealing methods.

Towards proalcool ii—a review of the brazilian bioethanol programme

Abstract: Since the creation of the National Alcohol Programme (NAP) in 1975, commonly known as “ProAlcool”, it has gone through a number of fluctuations reflecting Brazilian political, economic and energy priorities. In 1996–1997 over 175 Mt of sugarcane (65% of 270 Mt harvested) was converted to ethanol fuel. The ProAlcool started as a highly innovative programme, but in recent years has lost part of its technological zeal and in certain areas is becoming stagnant. This is due to a combination of reasons, e.g. unclear energy policy, high sugar prices in the international market and lower investment in ethanol production as a result of low international oil prices. A new impetus is needed to reflect changing economic and energy policy in Brazil. This paper reviews the implications for ProAlcool of the new economic policies and the possibilities for restructuring the programme to guarantee its survival as a pioneering and sustainable renewable energy source. This will bring new challenges, costs and opportunities to Brazilian society.

The use of biomass residues in the brazilian soluble coffee industry

Abstract: The objective of this paper is to discuss the use of coffee grounds in the Brazilian soluble coffee industry. This residue is used as a fuel in the boilers of the same industry; so, data about their utilization are presented and analysed, discussing the actual technology and the advantages of improving the drying of the biomass with the exhaust combustion gases. After that, an experimental study is reported on the characteristics of this material, which are important for the combustion process, including the transport, storage and drying, the mean diameter of the particles, talus angle, apparent and real density, sphericity, surface area, terminal velocity, spontaneous ignition temperature and heat of combustion.

A randomised, prospective comparison of allogeneic bone marrow and peripheral blood progenitor cell transplantation in the treatment of haematological malignancies

Abstract: We present the results of a prospective, randomised study comparing PBPC and BM focusing on engraftment, acute and chronic GVHD and survival. Forty patients with haematological malignancies received HLA-identical sibling BM (group A) or PBPC (group B). Evaluable patients were 19 (A) and 18 (B). Median age was 35 (17-56) in A and 29.5 (9-51) in B. Conditioning was mainly Bu-Cy2; GVHD prophylaxis was CSA-MTX. PBPC were harvested after 5 days of G-CSF 10 microg/kg/day. Median days for an ANC >0.5 x 10(9)/l was 18 (13-30) in A and 16 (11-25) in B (P = 0.10). Platelets >20 x 10(9)/l occurred at +17 (10-40) in A and +12 (9-36) in B (P = 0.01). The probability of > or =2 grade a-GVHD was 19% (A) and 27% (B) (P = 0.53). The probability of all grade c-GVHD was 70% with BM. In spite of the small number of patients in group B (PBPC), our data suggest the great majority of them will have c-GVHD (P = 0.08); extensive disease was present in 50 and 100%, respectively (P = 0.05). The estimates of overall survival for A and B at 1000 days are 51 and 47%, respectively (P = 0.67); DFS at 1000 days are 52 and 58%, respectively (P = 0.50). PBPC resulted in faster platelet engraftment. The incidence of acute and chronic GVHD was similar in both groups, but the severity of c-GVHD was higher with PBPC. No differences in survival and DFS have been observed to date.

Static output feedback controllers: stability and convexity

Abstract: The main objective of this paper is to solve the following stabilizing output feedback control problem: given matrices (A; B/sub 2/; C/sub 2/) with appropriate dimensions, find (if one exists) a static output feedback gain L such that the closed-loop matrix A-B/sub 2/LC/sub 2/ is asymptotically stable. It is known that the existence of L is equivalent to the existence of a positive definite matrix belonging to a convex set such that its inverse belongs to another convex set. Conditions are provided for the convergence of an algorithm which decomposes the determination of the aforementioned matrix in a sequence of convex programs. Hence, this paper provides a new sufficient (but not necessary) condition for the solvability of the above stabilizing output feedback control problem. As a natural extension, we also discuss a simple procedure for the determination of a stabilizing output feedback gain assuring good suboptimal performance with respect to a given quadratic index. Some examples borrowed from the literature are solved to illustrate the theoretical results.

The Thiol-specific Antioxidant Enzyme Prevents Mitochondrial Permeability Transition EVIDENCE FOR THE PARTICIPATION OF REACTIVE OXYGEN SPECIES IN THIS MECHANISM

Abstract: Mitochondrial swelling and membrane protein thiol oxidation associated with mitochondrial permeability transition induced by Ca2+ and inorganic phosphate are inhibited in a dose-dependent manner either by catalase, the thiol-specific antioxidant enzyme (TSA), a protein recently demonstrated to present thiol peroxidase activity, or ebselen, a selenium-containing heterocycle which also possesses thiol peroxidase activity. This inhibition of mitochondrial permeability transition is due to the removal of mitochondrial-generated H2O2 which can easily diffuse to the extramitochondrial space. Whereas ebselen required the presence of reduced glutathione as a reductant to grant its protective effect, TSA was fully reduced by mitochondrial components. Decrease in the oxygen concentration of the reaction medium also inhibits mitochondrial permeabilization and membrane protein thiol oxidation, in a concentration-dependent manner. The results presented in this report confirm that mitochondrial permeability transition induced by Ca2+ and inorganic phosphate is reactive oxygen species-dependent. The possible importance of TSA as an intracellular antioxidant, avoiding the onset of mitochondrial permeability transition, is discussed in the text.

Pinealectomy causes glucose intolerance and decreases adipose cell responsiveness to insulin in rats

Abstract: Although the pineal gland influences several physiological systems, only a few studies have investigated its role in the intermediary metabolism. In the present study, male Wistar rats, pinealectomized or sham-operated 6 wk before the experiment, were submitted to both intravenous glucose tolerance tests (IVGTT) and insulin binding as well as glucose transport assays in isolated adipocytes. The insulin receptor tyrosine kinase activity was assessed in liver and muscle. The insulin secretory response during the IVGTT was impaired, particularly in the afternoon, and the glucose transport responsiveness was 33% lower in pinealectomized rats. However, no difference was observed in the insulin receptor number of adipocytes between groups as well as in insulin-stimulated tyrosine kinase activity, indicating that the initial steps in the insulin signaling were well conserved. Conversely, a 40% reduction in adipose tissue GLUT-4 content was detected. In conclusion, pinealectomy is responsible for both impaired insulin secretion and action, emphasizing the influence of the pineal gland on glucose metabolism.

Prenatal and postnatal depression among low income Brazilian women

Abstract: Postnatal depression is a significant problem affecting 10-15% of mothers in many countries and has been the subject of an increasing number of publications. Prenatal depression has been studied less. The aims of the present investigation were: 1) to obtain information on the prevalence of prenatal and postnatal depression in low income Brazilian women by using an instrument already employed in several countries, i.e., the Edinburgh Postnatal Depression Scale (EPDS); 2) to evaluate the risk factors involved in prenatal and postnatal depression in Brazil. The study groups included 33 pregnant women interviewed at home during the second and third trimesters of pregnancy, and once a month during the first six months after delivery. Questions on life events and the mother's relationship with the baby were posed during each visit. Depressed pregnant women received less support from their partners than non-depressed pregnant women (36.4 vs 72.2%, P<0.05; Fisher exact test). Black women predominated among pre- and postnatally depressed subjects. Postnatal depression was associated with lower parity (0.4 ± 0.5 vs 1.1 ± 1.0, P<0.05; Student t-test). Thus, the period of pregnancy may be susceptible to socio-environmental factors that induce depression, such as the lack of affective support from the partner. The prevalence rate of 12% observed for depression in the third month postpartum is comparable to that of studies from other countries.

Optical Characterization of Dielectric and Semiconductor Thin Films by Use of Transmission Data

Abstract: A method to calculate the optical functions n(lambda) and k(lambda) by use of the transmission spectrum of a dielectric or semiconducting thin film measured at normal incidence is described. The spectrum should include the low-absorption region and the absorption edge to yield the relevant optical characteristics of the material. The formulas are derived from electromagnetic theory with no simplifying assumptions. Transparent films are considered as a particular case for which a simple method of calculation is proposed. In the general case of absorbing films the method takes advantage of some properties of the transmittance T(lambda) to permit the parameters in the two regions mentioned above to be calculated separately. The interference fringes and the optical path at the extrema of T(lambda) are exploited for determining with precision the refractive index and the film thickness. The absorption coefficient is computed at the absorption edge by an efficient iterative method. At the transition zone between the interference region and the absorption edge artifacts in the absorption curve are avoided. A small amount of absorption of the substrate is allowed for in the theory by means of a factor determined from an independent measurement, thus improving the quality of the results. Application of the method to a transmission spectrum of an a:Si(x)N(1-x):H film is illustrated in detail. Refractive index, dispersion parameters, film thickness, absorption coefficient, and optical gap are given with the help of tables and graphs.

Quantum Dynamical Manifestation of Chaotic Behavior in the Process of Entanglement

Abstract: Manifestation of chaotic behavior is found in an intrinsically quantum property. The entanglement process, quantitatively expressed in terms of the reduced density linear entropy, is studied for the $N$-atom Jaynes-Cummings model. For a given energy, initial conditions are prepared as minimum uncertainty wave packets centered at regular and chaotic regions of the classical phase space. We find for short times a faster increase in decoherence for the chaotic initial conditions as compared to regular ones, which have oscillatory increase.

Risk factors for death in patients with candidemia.

Abstract: Objective:To analyze possible risk factors for death among patients with nosocomial candidemia. To identify risk factors for death in patients with candidemia, we analyzed demographic, clinical, and microbiological data.Setting:Six tertiary hospitals in Brazil.Patients:A cohort of 145 patients with candidemia.Design:26 possible risk factors for death, including age, underlying disease, signs of deep-seated infection, neutropenia, number of positive blood cultures, removal of a central venous catheter, etiologic agent of the candidemia, susceptibility pattern of the isolate to amphotericin B, and antifungal treatment were evaluated by univariate stepwise logistic regression analysis.Results:Non-albicans species accounted for 63.4% of the candidemias. Risk factors for death in univariate analysis were older age, catheter retention, poor performance status, candidemia due to species other than Candida parapsilosis, hypotension, candidemia due to species other than Candida parapsilosis, and no antifungal treatment. In multivariate analysis, older age and non-removal of a central venous catheter were the only factors associated with an increased risk for death.Conclusions:These data suggest that patients with candidemia and a central venous catheter should have the catheter removed.

Phonon Raman scattering in R 1 − x A x MnO 3 + δ ( R = La , Pr ; A = Ca , Sr )

Abstract: Polarized Raman spectra of single and polycrystalline ${R}_{1\ensuremath{-}x}{A}_{x}{\mathrm{MnO}}_{3} (R=\mathrm{L}\mathrm{a},\mathrm{P}\mathrm{r};A=\mathrm{C}\mathrm{a},\mathrm{S}\mathrm{r})$ ceramic samples were studied as a function of temperature. For the rhombohedral ${\mathrm{LaMnO}}_{3.1}$ and ${\mathrm{La}}_{0.7}{\mathrm{Sr}}_{0.3}{\mathrm{MnO}}_{3},$ the observed Raman peaks were associated with modes arising from the folding of the Brillouin zone under lattice deformation. For the orthorhombic ${\mathrm{LaMnO}}_{3.0},$ the Raman spectra are consistent with the $\mathrm{Pnma}$ structure and show an anomalous softening of the 494 and 604 ${\mathrm{cm}}^{\ensuremath{-}1}$ modes below the antiferromagnetic ordering temperature ${T}_{N}\ensuremath{\simeq}140$ K. Polycrystalline samples of ${\mathrm{La}}_{0.5}{\mathrm{Ca}}_{0.5}{\mathrm{MnO}}_{3}$ show a dramatic change of the Raman spectra between 100 and 160 K, which was associated with the increase of the orthorhombic distortion observed by others for $T\ensuremath{\lesssim}240$ K. Other ${R}_{1\ensuremath{-}x}{A}_{x}{\mathrm{MnO}}_{3}$ single crystals, with small orthorhombic distortions, show Raman spectra which are similar to those observed in the rhombohedral samples.