Showing papers by "Federal University of Rio de Janeiro published in 2002"

Towards a functional classification of the freshwater phytoplankton

Abstract: This paper considers the structure of freshwater phytoplankton assemblages and promotes a scheme of vegetation recognition', based upon the functional associations of species represented in the plankton. These groups are often polyphyletic, recognizing commonly shared adaptive features, rather than common phylogeny, to be the key ecological driver. Thirty-one such associations are outlined and the basic pattern of their distinctive ecologies is outlined. An invitation to other plankton scientists to assist in the development of this scheme is issued.

The neural correlates of moral sensitivity: a functional magnetic resonance imaging investigation of basic and moral emotions.

Abstract: Humans are endowed with a natural sense of fairness that permeates social perceptions and interactions. This moral stance is so ubiquitous that we may not notice it as a fundamental component of daily decision making and in the workings of many legal, political, and social systems. Emotion plays a pivotal role in moral experience by assigning human values to events, objects, and actions. Although the brain correlates of basic emotions have been explored, the neural organization of “moral emotions” in the human brain remains poorly understood. Using functional magnetic resonance imaging and a passive visual task, we show that both basic and moral emotions activate the amygdala, thalamus, and upper midbrain. The orbital and medial prefrontal cortex and the superior temporal sulcus are also recruited by viewing scenes evocative of moral emotions. Our results indicate that the orbital and medial sectors of the prefrontal cortex and the superior temporal sulcus region, which are critical regions for social behavior and perception, play a central role in moral appraisals. We suggest that the automatic tagging of ordinary social events with moral values may be an important mechanism for implicit social behaviors in humans.

Production and detection of cold antihydrogen atoms

Abstract: A theoretical underpinning of the standard model of fundamental particles and interactions is CPT invariance, which requires that the laws of physics be invariant under the combined discrete operations of charge conjugation, parity and time reversal. Antimatter, the existence of which was predicted by Dirac, can be used to test the CPT theorem—experimental investigations involving comparisons of particles with antiparticles are numerous1. Cold atoms and anti-atoms, such as hydrogen and antihydrogen, could form the basis of a new precise test, as CPT invariance implies that they must have the same spectrum. Observations of antihydrogen in small quantities and at high energies have been reported at the European Organization for Nuclear Research (CERN)2 and at Fermilab3, but these experiments were not suited to precision comparison measurements. Here we demonstrate the production of antihydrogen atoms at very low energy by mixing trapped antiprotons and positrons in a cryogenic environment. The neutral anti-atoms have been detected directly when they escape the trap and annihilate, producing a characteristic signature in an imaging particle detector.

Plantas medicinais: a necessidade de estudos multidisciplinares

Abstract: This paper presents a program emphasizing ethnopharmacological approaches that could allow great success in the study of medicinal plants. The minimum ethnopharmacological research team should consist of a botanist, a chemist and a pharmacologist with each carrying the responsibility for answering in sequential fashion critical questions. The chemical composition and pharmacological properties of the very efficient medicinal plant Croton cajucara were investigated according to ethnopharmacological approaches. The study with this Croton proved to be both efficient and successful. This happy situation was only possible because a multidisciplinary team was involved getting the research done correctly. The ethnopharmacological study involving one other especies Copaifera will be cited.

Gênero, morbidade, acesso e utilização de serviços de saúde no Brasil

Abstract: O objetivo deste trabalho e analisar o perfil de morbidade referida, acesso e uso de servicos de saude em homens e mulheres no Brasil, segundo idade e regiao urbana e rural. Os dados da PNAD/98 mostram que as diferencas de genero na morbidade variam com a idade: desfavoraveis aos meninos ate os 10 anos e desfavoraveis as mulheres a partir dos 15 anos, aumentando ate os 64 anos e reduzindo apos esta idade. A alta prevalencia de atendimento indica que as barreiras de acesso dos que procuram servicos de saude sao pequenas. No entanto, o elevado percentual de nao procura face as necessidades percebidas sugere que as barreiras de acesso sao anteriores e dependem da oferta. A cobertura por planos de saude e bem maior na regiao urbana, mas nao ha diferencas de genero significantes nas regioes. As diferencas entre homens e mulheres nas taxas de uso curativo sao pequenas, se comparadas com as de uso preventivo, maiores para as mulheres, assim como as taxas de internacao, mesmo excluindo os partos. O financiamento das internacoes nao foi diferente entre homens e mulheres, ao contrario do financiamento de outros tipos de atendimento: maior cobertura por planos para mulheres na regiao urbana; na regiao rural, maior uso do SUS para as mulheres e maior desembolso de recursos proprios para os homens.

Stress-inducible protein 1 is a cell surface ligand for cellular prion that triggers neuroprotection

Abstract: Prions are composed of an isoform of a normal sialoglycoprotein called PrP(c), whose physiological role has been under investigation, with focus on the screening for ligands. Our group described a membrane 66 kDa PrP(c)-binding protein with the aid of antibodies against a peptide deduced by complementary hydropathy. Using these antibodies in western blots from two-dimensional protein gels followed by sequencing the specific spot, we have now identified the molecule as stress-inducible protein 1 (STI1). We show that this protein is also found at the cell membrane besides the cytoplasm. Both proteins interact in a specific and high affinity manner with a K(d) of 10(-7) M. The interaction sites were mapped to amino acids 113-128 from PrP(c) and 230-245 from STI1. Cell surface binding and pull-down experiments showed that recombinant PrP(c) binds to cellular STI1, and co-immunoprecipitation assays strongly suggest that both proteins are associated in vivo. Moreover, PrP(c) interaction with either STI1 or with the peptide we found that represents the binding domain in STI1 induce neuroprotective signals that rescue cells from apoptosis.

Cutaneous Infection by Fusarium Species in Healthy and Immunocompromised Hosts: Implications for Diagnosis and Management

Abstract: Infections by Fusarium species frequently involve the skin, either as the primary or the metastatic site. To better understand the pathophysiology of these infections, 43 new patients with fusariosis were evaluated, and the literature was reviewed. A total of 259 patients (232 immunocompromised and 27 immunocompetent) were identified. Skin involvement was present in 70% of patients, particularly in immunocompromised patients (72% vs. 52%; P=.03). In immunocompetent patients, cutaneous infections were characterized by preceding skin breakdown, localized involvement, slow pace of progression, and good response to therapy. In contrast, skin involvement in immunocompromised patients was only occasionally preceded by skin breakdown and typically was presented as rapidly progressive disseminated lesions at various stages of evolution. Metastatic skin lesions were associated with fungemia, neutropenia, and death. Skin was the single source of diagnosis for the majority of immunocompromised and immunocompetent patients. Recommendations for the prevention of fatal fusariosis originating from skin are presented.

Cellular prion protein transduces neuroprotective signals

Abstract: To test for a role for the cellular prion protein (PrP(c)) in cell death, we used a PrP(c)-binding peptide. Retinal explants from neonatal rats or mice were kept in vitro for 24 h, and anisomycin (ANI) was used to induce apoptosis. The peptide activated both cAMP/protein kinase A (PKA) and Erk pathways, and partially prevented cell death induced by ANI in explants from wild-type rodents, but not from PrP(c)-null mice. Neuroprotection was abolished by treatment with phosphatidylinositol-specific phospholipase C, with human peptide 106-126, with certain antibodies to PrP(c) or with a PKA inhibitor, but not with a MEK/Erk inhibitor. In contrast, antibodies to PrP(c) that increased cAMP also induced neuroprotection. Thus, engagement of PrP(c) transduces neuroprotective signals through a cAMP/PKA-dependent pathway. PrP(c) may function as a trophic receptor, the activation of which leads to a neuroprotective state.

Bacterial diversity of the rhizosphere of maize (Zea mays) grown in tropical soil studied by temperature gradient gel electrophoresis

Abstract: The bacterial diversity and population dynamics in the rhizosphere of two maize cultivars (Nitroflint and Nitrodent) grown in tropical soils was studied, by traditional cultivation techniques and 16S rRNA gene-based molecular analysis of DNA directly extracted from soil and rhizosphere samples. Rhizosphere and soil samples were taken at three different plant growth stages. Total aerobic bacterial counts were determined. Fingerprints of the most dominant bacterial population were generated by TGGE separation of 16S rRNA gene fragments amplified from total community DNA using eubacterial specific primers. To reduce the complexity of TGGE fingerprints or to analyse less abundant populations, primers specific for different phylogenetic groups have been used. A comparison of the cfu obtained for rhizosphere of both cultivars indicated significant differences only for rhizosphere and soil samples taken 40 days after sowing. However, a comparison of TGGE patterns indicated that the composition of the bacterial community analysed at different plant growth stages for both cultivars was similar. A comparison of α-, β-proteobacterial and actinomycete TGGE patterns of both cultivars confirmed this observation. The eubacterial TGGE profiles reflected strong seasonal population shifts in the bacterial rhizosphere community of both maize cultivars which could be also observed in the TGGE patterns of α- and β-proteobacteria and to a lesser extent for actinomycetes. The rhizosphere effect was much more pronounced for young roots compared to samples taken from mature maize plants. The rhizosphere fingerprints showed a reduced complexity for young plants with up to five dominating bands while for mature plants patterns similar to those of soil were observed. Sequencing of dominant clones indicated that the dominant population found at all plant growth stages can be assigned to Arthrobacter populations.

Proximal Point Algorithm On Riemannian Manifolds

Abstract: In this paper we consider the minimization problem with constraints. We will show that if the set of constraints is a Riemannian manifold of nonpositive sectional curvature, and the objective function is convex in this manifold, then the proximal point method in Euclidean space is naturally extended to solve that class of problems. We will prove that the sequence generated by our method is well defined and converge to a minimizer point. In particular we show how tools of Riemannian geometry, more specifically the convex analysis in Riemannian manifolds, can be used to solve nonconvex constrained problem in Euclidean, space.

World Federation of Societies of Biological Psychiatry (WFSBP) Guidelines for biological treatment of unipolar depressive disorders, part 1: acute and continuation treatment of major depressive disorder

Abstract: These practice guidelines for the biological treatment of unipolar depressive disorders were developed by an international Task Force of the World Federation of Societies of Biological Psychiatry (WFSBP) The goal for developing these guidelines was to systematically review all available evidence pertaining to the treatment of unipolar depressive disorders, and to produce a series of practice recommendations that are clinically and scientifically meaningful based on the available evidence These guidelines are intended for use by all physicians seeing and treating patients with these conditions The data used for developing these guidelines have been extracted primarily from various national treatment guidelines and panels for depressive disorders, as well as from meta-analyses and reviews on the efficacy of antidepressant medications and other biological treatment interventions identified by a search of the MEDLINE database and Cochrane Library The identified literature was evaluated with respect to the strength of evidence for its efficacy and was then categorized into four levels of evidence (A-D) This first part of the guidelines covers disease definition, classification, epidemiology and course of unipolar depressive disorders, as well as the management of the acute and continuation-phase treatment These guidelines are primarily concerned with the biological treatment (including antidepressants, other psychopharmacological and hormonal medications, electroconvulsive therapy, light therapy, adjunctive and novel therapeutic strategies) of young adults and also, albeit to a lesser extent, children, adolescents and older adults

Heterochromatic sequences in a Drosophila whole-genome shotgun assembly

Abstract: Background: Most eukaryotic genomes include a substantial repeat-rich fraction termed heterochromatin, which is concentrated in centric and telomeric regions. The repetitive nature of heterochromatic sequence makes it difficult to assemble and analyze. To better understand the heterochromatic component of the Drosophila melanogaster genome, we characterized and annotated portions of a whole-genome shotgun sequence assembly. Results: WGS3, an improved whole-genome shotgun assembly, includes 20.7 Mb of draft-quality sequence not represented in the Release 3 sequence spanning the euchromatin. We annotated this sequence using the methods employed in the re-annotation of the Release 3 euchromatic sequence. This analysis predicted 297 protein-coding genes and six non-protein-coding genes, including known heterochromatic genes, and regions of similarity to known transposable elements. Bacterial artificial chromosome (BAC)-based fluorescence in situ hybridization analysis was used to correlate the genomic sequence with the cytogenetic map in order to refine the genomic definition of the centric heterochromatin; on the basis of our cytological definition, the annotated Release 3 euchromatic sequence extends into the centric heterochromatin on each chromosome arm. Conclusions: Whole-genome shotgun assembly produced a reliable draft-quality sequence of a significant part of the Drosophila heterochromatin. Annotation of this sequence defined the intron-exon structures of 30 known protein-coding genes and 267 protein-coding gene models. The cytogenetic mapping suggests that an additional 150 predicted genes are located in heterochromatin at the base of the Release 3 euchromatic sequence. Our analysis suggests strategies for improving the sequence and annotation of the heterochromatic portions of the Drosophila and other complex genomes.

A standard stellar library for evolutionary synthesis - III. Metallicity calibration

Abstract: We extend the colour calibration of the widely used BaSeL standard stellar library (Lejeune et al. 1997, 1998) to non-solar metallicities, down to dex. Surprisingly, we find that at the present epoch it is virtually impossible to establish a unique calibration ofUBVRIJHKL colours in terms of stellar metallicity which is consistent simultaneously with both colour-temperature relations and colour-absolute magnitude diagrams (CMDs) based on observed globular cluster photometry data and on published, currently popular standard stellar evolutionary tracks and isochrones. The problem appears to be related to the long-standing incompleteness in our understanding of convection in late-type stellar evolution, but is also due to a serious lack of relevant observational calibration data that would help resolve, or at least further significant progress towards resolving this issue. In view of the most important applications of the BaSeL library, we here propose two different metallicity calibration versions: (1) the “WLBC 99” library, which consistently matches empirical colour-temperature relations and which, therefore, should make an ideal tool for the study of individual stars; and (2), the “PADOVA 2000” library, which provides isochrones from the Padova 2000 grid (Girardi et al. [CITE]) that successfully reproduce Galactic globular-cluster colour-absolute magnitude diagrams and which thus should prove particularly useful for studies of collective phenomena in stellar populations in clusters and galaxies.

Digital Signal Processing: System Analysis and Design

Abstract: From the Publisher: Digital signal processing lies at the heart of the communications revolution and is an essential element of key technologies such as mobile phones and the Internet. This book covers all the major topics in digital signal processing (DSP) design and analysis, supported by MATLAB examples and other modeling techniques. The authors explain clearly and concisely why and how to use digital signal processing systems; how to approximate a desired transfer function characteristic using polynomials and ratios of polynomials; why an appropriate mapping of a transfer function onto a suitable structure is important for practical applications; and how to analyze, represent, and explore the trade-off between time and frequency representation of signals. An ideal textbook for students, it will also be a useful reference for engineers working on the development of signal processing systems.

The effect of inoculating endophytic N2-fixing bacteria on micropropagated sugarcane plants

Abstract: The aim of this work was to evaluate the effect of the inoculation of endophytic N2-fixing bacteria on the development of micropropagated sugarcane plants. The endophytic population of each inoculated species was monitored during the growth period, and biological nitrogen fixation (BNF) contribution of each inoculation treatment was assessed using the 15N-isotope dilution technique. Seven different combinations of inoculum were used, using five endophytic diazotrophic species (Gluconacetobacter diazotrophicus, Herbaspirillum seropedicae, Herbaspirillum rubrisubalbicans, Azospirillum amazonense and Burkholderia sp.), originally isolated from sugarcane plants. The results showed a clear physiological effect on the development of the inoculated plants, resulting in alteration of the dry matter-partitioning pattern and increase on root dry matter as compared to uninoculated plants. Indeed, all inoculated diazotrophic species could be reisolated in high numbers from the rhizomes of the inoculated plants, even 400 days after inoculation (DAI), suggesting the establishment of the inoculated bacteria. However, a negative effect of the mixture of all five species on the survival of plantlets was observed 45 days after inoculation, just after acclimatization. The analysis of the BNF contribution using the 15N-isotope dilution technique showed that inoculation promoted some increase in the BNF contribution to the plant tissues. The best treatment was the mixture of all five strains, followed by the treatment with a mixture of Herbaspirillum spp. The contribution was much lower when the plants were inoculated with a mixture of G. diazotrophicus with A. amazonense and Burkholderia sp. A BNF contribution around 30% of total nitrogen accumulated was observed in micropropagated plants inoculated with the mixture of strains, suggesting that the combination of species in the inocula is the best strategy to improve sugarcane crops dependent on the biological nitrogen fixation process.

O gênero copaifera L.

Abstract: This review details the history, chemistry and pharmacology of the Copaifera L. genus (Leguminosae - Caesalpinoideae), including copaiba oils.

[Utilization of health care services in Brazil: gender, family characteristics, and social status].

Abstract: Estudo financiado pela Organizacao Pan-Americana da Saude atraves do Concurso Regional de Investigacion 1999 sobre “Genero y equidad en el acceso a la atencion de la salud en las reformas de los sistemas de salud y seguridad social”. HDP/HDR/RGP/81/5.3.

Review of Methods for Increasing Discrimination in Data Envelopment Analysis

Abstract: We present a review of methods for increasing discrimination between efficient DMUs in Data Envelopment Analysis. These methods were classified into two groups: those that incorporate a priori information and those that do not use or minimize the use of such a priori information. We also compare these methodologies regarding their specific characteristics.

Strength of short concrete columns confined with CFRP sheets

Abstract: The confinement of concrete columns provided by carbon fibre reinforced plastic (CFRP) sheets can be an efficient technique for their structural strengthening. The principal advantages of this technique are the high strength-to-weight ratio, good fatigue properties, non-corroding characteristics of the CFRP, and the facility of its application.

Morphology and mechanical properties of unidirectional sisal-epoxy composites

Abstract: Plant fibers are of increasing interest for use in composite materials. They are renewable resources and waste management is easier than with glass fibers. In the present study, longitudinal stiffn ...

Efficient use of airport capacity

Abstract: The capacity of 35 Brazilian domestic airports was analyzed with a view to determining which of them were efficient in terms of the number of passengers processed Data Envelopment Analysis (DEA) methodology was employed to construct the efficient frontier for the sample, to reflect which of the airports used airport resources efficiently and which offered surplus in these same facilities, and in what proportion On the basis of passenger demand forecasts, it was possible to determine, for each airport, the periods when capacity expansions would become necessary to maintain services at standards currently perceived by passengers

O nativo relativo

Abstract: Este artigo tenta extrair as implicacoes teoricas do fato de que a antropologia nao apenas estuda relacoes, mas que o conhecimento assim produzido e ele proprio uma relacao. Propoe-se, assim, uma imagem da atividade antropologica como fundada no pressuposto de que os procedimentos caracteristicos da disciplina sao conceitualmente de mesma ordem que os procedimentos investigados. Entre tais implicacoes, esta a recusa da nocao corrente de que cada cultura ou sociedade encarna uma solucao especifica de um problema generico, preenchendo uma forma universal (o conceito antropologico) com um conteudo particular (as concepcoes nativas). Ao contrario, a imagem aqui proposta sugere que os problemas eles mesmos sao radicalmente diversos, e que o antropologo nao sabe de antemao quais sao eles.

Basic cell biology of Trypanosoma cruzi.

Abstract: The paper reviews basic aspects of the biology of Trypanosoma cruzi emphasizing the following topics: (a) developmental stages of the life cycle in the vertebrate and invertebrate hosts; (b) the cytoskeleton of the protozoan, especially the sub-pellicular microtubules; (c) the flagellum, emphasizing its attachment to the protozoan body through specialized junctions; (d) the kinetoplast-mitochondrion complex, describing its structural organization and the replication of the kinetoplast-DNA; (e) the peroxisome (glycosome) and its role in the metabolism of the cell; (f) the acidocalcisome, describing its morphology, biochemistry and functional role; (g) the cytostome and the endocytic pathway; (h) the organization of the endoplasmic reticulum-Golgi complex; (i) the nucleus, describing its structural organization during interphase and division, and (j) basic aspects of the process of interaction of the parasite with host cells.

Cofactors of serine racemase that physiologically stimulate the synthesis of the N-methyl-D-aspartate (NMDA) receptor coagonist D-serine.

Abstract: High levels of d-serine occur in the brain, challenging the notion that d-amino acids would not be present or play a role in mammals. d-serine levels in the brain are even higher than many l-amino acids, such as asparagine, valine, isoleucine, and tryptophan, among others. d-serine is synthesized by a serine racemase (SR) enzyme, which directly converts l- to d-serine. We now report that SR is a bifunctional enzyme, producing both d-serine and pyruvate in cultured cells and in vitro. Transfection of SR into HEK 293 cells elicits synthesis of d-serine and augmented release of pyruvate to culture media. We identified substances present in HEK 293 and astrocyte cell extracts that strongly stimulate d-serine production by SR and elicit production of pyruvate. Experiments with recombinant enzyme reveal that Mg2+ and ATP present in the cell extracts are physiological cofactors and increase 5- to 10-fold the rates of racemization and production of pyruvate. As much as three molecules of pyruvate are synthesized for each molecule of d-serine produced by SR. This finding constitutes a previously undescribed mechanism underlying d-amino acid synthesis in mammals, different from classical amino acid racemases present in bacteria. Our data link the production of d-serine to the energy metabolism, with implications for the metabolic and transmitter crosstalk between glia and neurons.