bluuebunny/crossref_metadata_2025 huggingface dataset:
Bacterioplankton abundance, biomass and production in a Brazilian coastal lagoon and in two German lakes
Authors: FURTADO ANDRÉ L. S. , CASPER PETER , ESTEVES FRANCISCO A.
Published: April 2005

The bacterioplanktonic abundance, biomass, and production within a tropical lagoon (Cabiúnas, Brazil) and two temperate lakes (Stechlin and Dagow, Germany) were compared. Bacterial abundance and production were significantly different among the three water bodies. The lowest bacterial production ( 0.8mug C l-1 d-1) was observed in the tropical Cabiúnas Lagoon despite its higher mean temperature and dissolved organic carbon concentration. Highest bacterioplankton abundance ( 2.6 x 10(9) cells l-1) and production ( 68.5mug C l-1 d-1) were measured in eutrophic Lake Dagow. In oligotrophic Lake Stechlin, the lowest bacterial biomass ( 48.05mug C l-1) was observed because of lower bacterial biovolume ( 0.248mum³) and lower bacterial abundance. Bacterial populations in the temperate lakes show higher activity (production/biomass ratio) than in the tropical lagoon. The meaning of isotopic dilution and leucine incorporation by non-bacterial micro-organisms were evaluated in the oligotrophic temperate system. Leucine uptake by non-bacterial micro-organisms did not have significant influence on bacterial production.
Evidence of mingling between contrasting magmas in a deep plutonic environment: the example of Várzea Alegre, in the Ribeira Mobile Belt, Espírito Santo, Brazil
Authors: MEDEIROS SILVIA R. , WIEDEMANN-LEONARDOS CRISTINA M. , VRIEND SIMON
Published: April 2005

At the end of the geotectonic cycle that shaped the northern segment of the Ribeira Mobile Belt (Upper Proterozoic to Paleozoic age), a late to post-collisional set of plutonic complexes, consisting of a wide range of lithotypes, intruded all metamorphic units. The Várzea Alegre Intrusive Complex is a post-collisional complex. The younger intrusion consists of an inversely zoned multistage structure envolved by a large early emplaced ring of megaporphyritic charnoenderbitic rocks. The combination of field, petrographic and geochemical data reveals the presence of at least two different series of igneous rocks. The first originated from the partial melting of the mantle. This was previously enriched in incompatible elements, low and intermediate REE and some HFS-elements. A second enrichment in LREE and incompatible elements in this series was due to the mingling with a crustal granitic magma. This mingling process changed the composition of the original tholeiitic magma towards a medium-K calc-alkalic magma to produce a suite of basic to intermediate rock types. The granitic magma from the second high-K, calc-alkalic suite originated from the partial melting of the continental crust, but with strong influence of mantle-derived melts.
A Temnospondyl amphibian from the Rio do Rasto Formation, Upper Permian of southern Brazil
Authors: DIAS ELISEU V. , BARBERENA MARIO C.
Published: April 2005

A partially preserved lower jaw constitutes the holotype of Bageherpeton longignathus n. g., n. sp., a probable archegosaurid amphibian, which is here assigned to the Platyoposaurinae. The material was collected in the beds of the Rio do Rasto Formation outcropping in Rio Grande do Sul State, southern Brazil. This is the second archegosaurid described for the Permian of Brazil. Prionosuchus plummeri Price 1948, from the Pedra do Fogo Formation in the Parnaiba Basin (northeastern Brazil), is the first. The new taxon differs from other platyoposaurs by the presence of an extremely elongated precoronoid that participates in the mandibular symphysis.
A duality result between the minimal surface equation and the maximal surface equation
Authors: ALÍAS LUIS J. , PALMER BENNETT
Published: April 2005

In this note we show how classical Bernstein's theorem on minimal surfaces in the Euclidean space can be seen as a consequence of Calabi-Bernstein's theorem on maximal surfaces in the Lorentz-Minkowski space (and viceversa). This follows from a simple but nice duality between solutions to their corresponding differential equations.
On deformation of foliations with a center in the projective space
Authors: MOVASATI HOSSEIN
Published: April 2005

Let  be a foliation in the projective space of dimension two with a first integral of the type , where F and G are two polynomials on an affine coordinate,  =  and g.c.d.(p, q) = 1. Let z be a nondegenerate critical point of , which is a center singularity of , and  be a deformation of  in the space of foliations of degree deg() such that its unique deformed singularity  near z persists in being a center. We will prove that the foliation  has a first integral of the same type of . Using the arguments of the proof of this result we will give a lower bound for the maximum number of limit cycles of real polynomial differential equations of a fixed degree in the real plane.
Functional role of a glycolipid in directional movements of neurons
Authors: MENDEZ-OTERO ROSALIA , SANTIAGO MARCELO F.
Published: April 2005

Migration of neurons from their site of origin to their final destination is a critical and universal step in the formation of the complex structure of the nervous system. The migratory process is thought to be governed in part by genetically and epigenetically defined sequences of signals which are interpreted by migrating cells. The molecular mechanisms that underlie neuronal migration have been the subject of intense investigation. As in other developmental processes, many molecules must participate in neuronal migration. Some molecules, such as cell adhesion molecules and motor proteins, may contribute to discrete steps in the migration act; others, like extracellular signaling molecules, may regulate the activation and/or termination of the migration program. In this article we review findings from our group that demonstrate the functional role(s) of a specific glycolipid in neuronal migration and neurite outgrowth in the developing and adult nervous system.
Optimal image quantization, perception and the median cut algorithm
Authors: MOTA CICERO , GOMES JONAS , CAVALCANTE MARIA I. A.
Published: April 2005

We study the perceptual problem related to image quantization from an optimization point of view, using different metrics on the color space. A consequence of the results presented is that quantization using histogram equalization provides optimal perceptual results. This fact is well known and widely used but, to our knowledge, a proof has never appeared on the literature of image processing.
Cell swelling and ion redistribution assessed with intrinsic optical signals
Authors: WITTE OTTO W. , NIERMANN HEIKE , HOLTHOFF KNUT
Published: April 2005

Cell volume changes are associated with alterations of intrinsic optical signals (IOS). In submerged brain slices in vitro, afferent stimulation induces an increase in light transmission. As assessed by measurement of the largely membrane impermeant ion tetramethylammonium (TMA) in the extracellular space, these IOS correlate with the extent and time course of the change of the extracellular space size. They have a high signal to noise ratio and allow measurements of IOS changes in the order of a few percent. Under conditions of reduced net KCl uptake (low Cl solution) a directed spatial buffer mechanism (K syphoning) can be demonstrated in the neocortex with widening of the extracellular space in superficial layers associated with a reduced light transmission and an increase of extracellular K concentration. The nature of the IOS under pathophysiological conditions is less clear. Spreading depressions first cause an increase of light transmission, then a decrease. Such a decrease has also been observed following application of NMDA where it was associated with structural damage. Pharmacological analyses suggest that under physiological conditions changes of extracellular space size are mainly caused by astrocytic volume changes while with strong stimuli and under pathophysiological conditions also neuronal swelling occurs. With reflected light usually signals opposite to those observed with transmitted light are seen. Recording of IOS from interface slices gives very complex signals since under these conditions an increase of light transmission has been reported to be superimposed by a decrease of the signal due to mechanical lensing effects of the slice surface. Depending on the method of measurement and the exact conditions, several mechanisms may contribute to IOS. Under well defined conditions IOS are a useful supplementary tool to monitor changes of extracellular volume both in space and time.
Genome engineering via homologous recombination in mouse embryonic stem (ES) cells: an amazingly versatile tool for the study of mammalian biology
Authors: BABINET CHARLES , COHEN-TANNOUDJI MICHEL
Published: April 2005

The ability to introduce genetic modifications in the germ line of complex organisms has been a long-standing goal of those who study developmental biology. In this regard, the mouse, a favorite model for the study of the mammals, is unique: indeed not only is it possible since the late seventies, to add genes to the mouse genome like in several other complex organisms but also to perform gene replacement and modification. This has been made possible via two technological breakthroughs: 1) the isolation and culture of embryonic stem cells (ES), which have the unique ability to colonize all the tissues of an host embryo including its germ line; 2) the development of methods allowing homologous recombination between an incoming DNA and its cognate chromosomal sequence (gene ''targeting''). As a result, it has become possible to create mice bearing null mutations in any cloned gene (knock-out mice). Such a possibility has revolutionized the genetic approach of almost all aspects of the biology of the mouse. In recent years, the scope of gene targeting has been widened even more, due to the refinement of the knock-out technology: other types of genetic modifications may now be created, including subtle mutations (point mutations, micro deletions or insertions, etc.) and chromosomal rearrangements such as large deletions, duplications and translocations. Finally, methods have been devised which permit the creation of conditional mutations, allowing the study of gene function throughout the life of an animal, when gene inactivation entails embryonic lethality. In this paper, we present an overview of the methods and scenarios used for the programmed modification of mouse genome, and we underline their enormous interest for the study of mammalian biology.
The pathogenesis of Chagas' disease: when autoimmune and parasite-specific immune responses meet
Authors: SOARES MILENA B. P. , PONTES-DE-CARVALHO LAIN , RIBEIRO-DOS-SANTOS RICARDO
Published: April 2005

Chagas' disease is a major health problem in Latin America, where it constitutes one of the leading causes of heart failure. About one fourth of Trypanosoma cruzi-infected individuals develop chronic chagasic cardiomyopathy (CChC), the most severe form of the disease. CChC is histologically characterized by the presence of multifocal inflammatory infiltrates in the heart, composed mainly by mononuclear cells, usually adhered to myocytes and leading to myocytolysis, and frequently by interstitial fibrosis. The pathogenesis of CChC is still unclear, despite intense investigations both in human beings and in animal models of the disease. Although tissue parasitism is rare in the chronic phase of infection, an immune response targeted to persistent parasites or parasite antigens is suggested, by some authors, as the pathogenic mechanism of CChC. Other researchers affirm that the lack of correlation between tissue parasitism and intensity of inflammation suggests, along with the presence of autoreactive immune responses, that CChC results from the action of an autoimmune response. Herein we review reports from the literature and our own data, which together indicate, on one hand, the participation of parasite-specific immune responses and, on the other hand, clearly demonstrate the participation of heart-specific immune responses in the pathogenesis of CChC. Moreover, multiple factors may determine whether an individual in the indeterminate form of the disease will develop CChC. The mechanisms by which T. cruzi breaks immunological tolerance to heart antigens are also discussed.
High and low frequency erosive and constructive cycles in estuarine beaches: an example from Garcez Point, Bahia/Brazil
Authors: BITTENCOURT ABÍLIO C.S.P. , LESSA GUILHERME C. , DOMINGUEZ JOSÉ M.L. , MARTIN LOUIS , VILAS BÔAS GERALDO S. , FARIAS FÉLIX F.
Published: April 2005

Monitoring of the morphodynamic variations of the beaches associated with an estuary contiguous with Garcez Point, Bahia, Brazil, and the superposition of aerial photographs from the region, show the presence of distinctive erosive and constructive cycles of low and high frequencies. Between 1959 and 1989, one event of shoreline erosion and progradation was recognized on the oceanic beaches just outside the estuary. Inside the estuary, an erosion phase at the southern margin coincides with a constructive phase at the other side, and vice-versa. On the southern estuarine beach, low-frequency cycles of erosion and progradation are also perceived, but with the inverse trend when compared to the contiguous oceanic beach. During the beach monitoring period (February/1991 to July/1992), the oceanic beach showed retreat rates varying from 23.7m/year, at the channel entrance, to 1.0m/year, three kilometers away from it. During the same period, the estuarine beach advanced at a rate of 60.3m/year. The long-term dynamics of the shoreline position in both sides of the estuarine entrance appears to be related to the position of the channel in the ebb-tidal delta.
Phytochemical characterization of essential oil from Ocimum selloi
Authors: MORAES LILIA A.S. , FACANALI ROSELAINE , MARQUES MARCIA ORTIZ M. , LIN CHAU MING , MEIRELES M. ANGELA A.
Published: April 2005

Ocimum selloi Benth, a native plant of Brazil, has medicinal uses as anti-diarrheic, antispasmodic and anti-inflammatory product. The yield of essential oils of the inflorescences, containing flowers and seeds, was 0.6%, and the yield of leaves, collected in two different seasons, was 0.25% (June 2000) and 0.20% (January 2001), respectively. The essential oils of the inflorescences and leaves presented as major constituents trans-anethol (41.34%, 45.42%, 58.59%) and methyl chavicol (27.10%, 24.14%, 29.96%).
Semiquantitative mercury determination in fish: a tool for poisoning prevention
Authors: YALLOUZ ALLEGRA V. , CALIXTO TATIANA , HACON SANDRA
Published: April 2005

Human exposure to mercury intoxication through contaminated fish ingestion has been well studied, mainly among Japanese population. The Brazilian population, particulaly in the Amazon region, is now in focus due to findings of fish contamination. Major health impacts caused by mercury affect mostly people who have a regular fish diet. A continuous checking for mercury content in the most consumed fish could prevent human intoxication. A simple, non-instrumental method to allow a continuous checking of the mercury content in fish was developed. Based on this method, we are proposing a prevention action where community agents can be trained to perform fish analysis. Technical Schools and Universities located nearby the affected areas would be in charge of quality control programs for the fish analysis as well as for the selection, training and update for operators.
Maximum principles for hypersurfaces with vanishing curvature functions in an arbitrary Riemannian manifold
Authors: FONTENELE FRANCISCO X. , SILVA SÉRGIO L.
Published: April 2005

In this paper we generalize and extend to any Riemannian manifold maximum principles for Euclidean hypersurfaces with vanishing curvature functions obtained by Hounie-Leite.
Two-dimensional map of direction selectivity in cortical visual area MT of Cebus monkey
Authors: DIOGO ANTONIA CINIRA M. , SOARES JULIANA G. M. , ALBRIGHT THOMAS D. , GATTASS RICARDO
Published: April 2005

We studied the spatial organization of direction of motion in visual area MT of the Cebus apella monkey. We used arrays of 6 (700 µm apart) parallel electrodes in penetrations tangential to the cortical layers to record multi-unit responses to moving bars, at 200 µm steps. We determined the direction selectivity at each recording site. The data from single penetrations showed cyclic and gradual changes in the direction selectivity of clusters of cells, intermixed with abrupt 180º discontinuities along the electrode track. In order to obtain maps of direction of motion selectivity, we examined the spatial distribution of direction of motion in MT and we applied a method to determine the location of the centers of radial arrangements of direction selectivity. This tangential organization is characterized by slow continuous changes in direction of motion, interrupted by discontinuities. The changes in direction selectivity are organized radially in a pinwheel fashion and in slabs of linear variation. The pinwheel arrangements have 800-1400 µm in diameter. The size of the radial arrangement is comparable to the point image size in area MT at each eccentricity.
A yeast-based model system for cloning secreted and membrane proteins
Authors: SURPILI MARCELO J. , MÜLLER-RÖBER BERND , WILLMITZER LOTHAR
Published: April 2005

The targeting of proteins to cell organelles and membranes, or of proteins destined to secretion, is coordinated by signal sequences located at the 5´-end of their respective genes. A signal sequence trap system was envisaged in which a truncated version of the yeast acid phosphatase pho5 gene lacking the start codon and signal sequence could serve as a reporter gene. A fraction enriched in 5´-end fragments obtained by PCR from a potato guard-cell cDNA library was cloned in frame to the acid phosphatase gene and the acid phosphatase activity was assayed directly in yeast colonies grown on selective medium. Putative signal sequences targeting the acid phosphatase to the membrane or to the outside of the cell were used to screen the cDNA bank in order to recover the original full-size sequence which gave rise to the signal sequence. Two unknown sequences displaying marked tissue-specific expression were retrieved, one of them (YE139) with a higher expression level in green buds and stem cells, and the other one (YE290) with a higher expression level in androceum, gyneceum, and roots. The limitations of the system are further analyzed using other sequences as control.
Removal of the cortical projections alters expression of NOS in the different cell types of the superficial layers of the superior colliculus in rats
Authors: TENÓRIO FRANK , GIRALDI-GUIMARÃES ARTHUR , MENDEZ-OTERO ROSALIA
Published: April 2005

Nitric oxide has several biological roles and nitric oxide synthase (NOS) is expressed in the nervous system, and co-localizes with NADPH-diaphorase. The superficial layers of the superior colliculus (SC), which receive retinal and cortical inputs, present NADPH-d staining in a sub-population of neurons that include all cell types. We have previously shown, by NADPH-diaphorase, that eye enucleation alters the intracellular distribution of NOS. Here, we studied the effect of cortical ablation on NOS expression by neurons in collicular superficial layers. Our results show that cortical ablation alters the proportion of different NOS-positive cell types, but not the intracellular distribution of the enzyme.
On four dimensional Dupin hypersurfaces in Euclidean space
Authors: RIVEROS CARLOS M. C. , TENENBLAT KETI
Published: April 2005

Dupin hypersurfaces in five dimensional Euclidean space parametrized by lines of curvature, with four distinct principal curvatures, are considered. A generic family of such hypersurfaces is locally characterized in terms of the principal curvatures and four vector valued functions of one variable. These functions are invariant by inversions and homotheties.
Does advertisement call variation coincide with genetic variation in the genetically diverse frog taxon currently known as Leptodactylus fuscus (Amphibia: Leptodactylidae)?
Authors: HEYER W. RONALD , REID YANA R.
Published: April 2005

The frog Leptodactylus fuscus is found throughout much of South America in open and disturbed habitats. Previous study of genetic differentiation in L. fuscus demonstrated that there was lack of genetic exchange among population units consistent with multiple species, rather than a single species. We examine advertisement vocalizations of L. fuscus to determine whether call variation coincides with genetic differentiation. Calls were analyzed for 32 individual frogs from 25 localities throughout the distributional range of L. fuscus. Although there is variation in calls among geographic samples, call variation is not concordant with genetic variation or geographic distance and the call variation observed is less than that typically found among other closely related species of Leptodactylus. This study is an example of the rare pattern of strong genetic differentiation unaccompanied by salient differences in advertisement calls. The relative infrequency of this pattern as currently understood may only reflect the lack of detailed analyses of genetic and acoustic differentiation within population systems currently understood as single species with substantial geographic distributions.
Karyotypic analysis in species of the genus Dasyprocta (Rodentia: Dasyproctidae) found in Brazilian Amazon
Authors: RAMOS ROSEMAR S. L. , VALE WILLIAM G. , ASSIS FÁTIMA L.
Published: April 2005

A total of 30 animals of the genus Dasyprocta were cytogenetically studied. They belong to the following species: D. prymnolopha (N=20), D. leporina (N=6), D. fuliginosa (N=1) and Dasyprocta sp. (N=3) (Dasyproctidae, Hystricognathi). Cell suspensions were obtained by peripheral blood culture, besides bone marrow and spleen cells, from D. prymnolopha and D. leporina. The diploid number was 64/65 for all samples. The karyotypes showed similarity, and chromosomal polymorphism was not detected by Giemsa conventional staining and G banding. The constitutive heterochromatin distribution at the pericentromeric region of all the chromosomes was similar in all species. D. prymnolopha, D. leporina and Dasyprocta sp. presented variation in the heterochromatical block size at one of the homologues of the A18 pair. D. fuliginosa presented the heterochromatin uniformly distributed in all chromosomes. There was not variation in the NORs pattern in the species studied.
Upper Pleistocene deposits of the Comprida Island (São Paulo State) dated by thermoluminescence method
Authors: SUGUIO KENITIRO , TATUMI SONIA H. , KOWATA EMÍLIA A. , MUNITA CASIMIRO S. , PAIVA ROSEMEIRE P.
Published: April 2005

The Cananéia (Upper Pleistocene) and the Comprida Island (Holocene) formations, outcropping in the Comprida island (SP) have been mapped using geomorphological and lithological criteria. Only one sample of the Cananéia Formation, collected in the homonymous island in front of the Comprida Island, was beyond the limit of the standard radiocarbon method. But since the publication of the geological map of the area in 1978, there has been some doubt on the real occurrence of Pleistocene deposits in southern extremity of Comprida Island. This paper deals with the results of thermoluminescence (TL) ages of eight samples from Comprida Island, which corroborate the Pleistocene age assumed during mapping surveys of these deposits. On the other hand, possible interpretations of the obtained ages, in relation to their depositional environments and related northern hemisphere Quaternary glaciations, are presented.
The coming of age of cosmophysics
Authors: Jacob Maurice
Published: April 2005

''Cosmophysics'' as reviewed is a multidisciplinary domain which brings together astroparticle physics, fundamental physics in space and topics related to the structure and evolution of the Universe. It represents a growing interface between high-energy particle physics and astro-physics. This paper presents a general overview of the subject, focusing on cosmology, cosmic rays, dark matter searches and the soon-expected observation of gravitational waves.
On properness of minimal surfaces with bounded curvature
Authors: Bessa Gregório P. , Jorge Luquésio P. M.
Published: April 2005

We show that immersed minimal surfaces in the euclidean 3-space with bounded curvature and proper self intersections are proper. We also showthat restricted to wide components the immersing map is always proper, regardless the map being proper or not. Prior to these results it was only known that injectively immersed minimal surfaces with bounded curvature were proper.
On clutch size and hatching success of the South American turtles Podocnemis expansa (Schweigger, 1812) and P. unifilis Troschel, 1848 (Testudines, Podocnemididae)
Authors: Vanzolini Paulo Emilio
Published: April 2005

Data on clutch size and hatching success of P. expansa were gathered for seven beaches traditionally used by the species and re-analyzed statistically by means of regression analysis, of the number of eggs on the number of females (or nests) and of the number of young on the number of eggs. All regressions were linear, passed through the origin and had excellent fits. Average clutch size varied from 75 to 123, and presented geographic differentiation: (i) Rio Orinoco, (ii) Rio Trombetas + Rio Branco and (iii) Rio Juruá + Rio Purus. Average hatching success was ca. 83%. In P. unifilis there was also geographic variation in clutch size, the Iquitos area showing the highest values. Hatching success of P. unifilis was uniformly high: only one sample, from Iquitos, had less than 90% success. The outstanding fit of the clutch size regressions leads one to consider egg volume variability, which was found to be high in both species, in contradiction with current optimal egg size theory.
Stereological tools in biomedical research
Authors: Mandarim-de-Lacerda Carlos A.
Published: April 2005

Stereological studies are more and more frequent in literature, particularly in the development/evolution, pathology, and neurosciences areas. The stereology challenge is to understand the structural inner threedimensional arrangement based on the analysis of the structure slices only showing two-dimensional information. Cavalieri and Scherle's methods to estimate volume, and Buffon's needle problem, are commented in the stereological context. A group of actions is needed to appropriately quantify morphological structures (unbiased and reproducibly), e.g. sampling, isotropic and uniform randomly sections (Delesse's principle), and updated stereological tools (disector, fractionator, nucleator, etc). Through the correct stereology use, a quantitative study with little effort could be performed: efficiency in stereology means a minimum slices sample counting (little work), low cost (slices preparation), but good accuracy. In the present text, a short review of the main stereological tools is done as a background basis to non-expert scientists.
The Botrychiopsis genus and its biostratigraphic implications in Southern Paraná Basin
Authors: Jasper André , Guerra-Sommer Margot , Cazzulo-Klepzig Miriam , Menegat Rualdo
Published: April 2005

Botrychiopsis has been considered an important floristic element of Westphalian/Artinskian associations of the Paraná Basin. The occurrence of Botrychiopsis in roof-shales of the Rio Bonito Formation in Southern Paraná Basin (Quitéria area), supported by the identification of Botrychiopsis valida, enlarges the genus biochron. Consequently, the stratigraphic hierarchy for Botrychiopsis plantiana and Botrychiopsis valida was defined for the Paraná Basin. Although it is climatically controlled and related to a deglaciation icehouse stage, stratigraphic distribution of the genus presents a substantial climate tolerance, from cold/cool to warm/temperate conditions. A new phytostratigraphic zonation is proposed for the southern portion of the basin that includes the Botrychiopsis Zone (Asselian/Kungurian), which is subdivided into the Botrychiopsis plantiana (Asselian/Artinskian) and Botrychiopsis valida (Late Artinskian/Kungurian) subzones.
Use of pedological maps in the identification of sensitivity of soils to acidic deposition: application to Brazilian soils
Authors: Melfi Adolpho J. , Montes Celia R. , Carvalho Adilson , Forti Maria Cristina
Published: April 2005

The pedogeochemical maps present the spatial distribution of soils according to crystalochemical parameters (clay fraction) and physic-chemical aspects of the sorting complex (CEC and BS). These maps are adequate tool for environmental studies and particularly, for the analysis of the terrestrial ecosystem sensibility to acidic deposition. The pedogeochemical maps of the Brazilian soils, elaborated using FAO SoilWorld Map, allowed establishing the soil distribution according to 5 classes of vulnerability to acidic deposition, as defined by Stockholm Environmental Institute (SEI). From these maps, it is observed that about 50% of the Brazilian soils are high vulnerable to acidic deposition and can be included within the most sensitive class. This group is formed by well-developed and mature soils, constituted by clay minerals of kaolinite type associated with variable amount of gibbsite. About 8% of the soils can be considered as the least sensitive class. They correspond to Topomorphic Vertisols (Vertissolo, Embrapa 1999), Planosols (Planossolo, Embrapa 1999) and saline soils. Finally, the remaining soils represent the balanced media that dominate the northeastern semiarid zones and the south and northeastern subtropical zones.
Combination sensitivity and processing of communication calls in the inferior colliculus of the Moustached Bat Pteronotus parnellii
Authors: Portfors Christine V.
Published: April 2005

Many animals use complex communication calls in social behaviors. In some species we know the features in the calls that elicit particular behaviors, but we do not understand how the auditory system encodes the calls. Nor do we understand the mechanisms underlying neural selectivity to calls. Our studies of the auditory midbrain of the Moustached Bat Pteronotus parnellii have revealed a neural mechanism important for generating selective responses to calls. Neurons that integrate information across different frequencies show selectivity to communication calls. "Combination sensitivity" may be a common mechanism for encoding complex sounds because it is also important for encoding echolocation signals.
Penguins and their noisy world
Authors: Aubin Thierry
Published: April 2005

Penguins identify their mate or chick by an acoustic signal, the display call. This identification is realized in a particularly constraining environment: the noisy world of a colony of thousands of birds. To fully understand how birds solve this problem of communication, we have done observations, acoustic analysis, propagation and playback experiments with 6 species of penguins studied in the field. According to our results, it appears that penguins use a particularly efficient ''anti-confusion'' and ''anti-noise'' coding system, allowing a quick identification and localization of individuals on the move in a noisy crowd.
Tonal vocalizations in a noisy environment: an approach to their semi-automatic analysis and examples of its application
Authors: Mundry Roger , Sommer Christian
Published: April 2005

Vocalizations with an emphasized fundamental are common in many species of animals. Such calls can presumably be sufficiently described by measures of their fundamental shape or 'contour'. Here we describe a software we developed to analyze such vocalizations semi-automatically. The software is particularly designed to cope with vocalizations recorded in a noisy environment. Some of the algorithms implemented (e.g. signal detection, contour detection, contour measurement, validation) and some preliminary applications dealing with calls of different species of birds are presented. Finally, we briefly discuss the possible significance of such vocalizations.
Acoustic evolution in crickets: need for phylogenetic study and a reappraisal of signal effectiveness
Authors: Desutter-Grandcolas Laure , Robillard Tony
Published: April 2005

Cricket stridulums and calls are highly stereotyped, except those with greatly modified tegmina and/or vena-tion, or ''unusual'' frequency, duration and/or intensity. This acoustic diversity remained unsuspected until recently, and current models of acoustic evolution in crickets erroneously consider this clade homogeneous for acoustic features. The few phylogenetic studies analyzing acoustic evolution in crickets demonstrated that acoustic behavior could be particularly labile in some clades. The ensuing pattern for cricket evolution is consequently extremely complex. We argue that: (1) phylogeny should always be considered when analyzing acoustic evolution, whatever characters are considered (signals, stridulums or behaviors). Consequently, future studies should be devoted to entire clades, and not consider isolated taxa; character and character state definitions should allow significant reconstructions of character evolutionary transformations; and homologies should be carefully defined for all characters, including behavior. (2) The factors responsible for song effectiveness should be reconsidered and hypotheses on their potential influence on signal evolution tested jointly by phylogenies (for example, to assess correlated transformations of acoustic and ecological features), and population studies (for example, to correlate call range and population structure, or test the predation risk associated with a signal structure). Better understanding these points should help clarifying acoustic evolution in crickets.
Differences in the whistle characteristics and repertoire of Bottlenose and Spinner Dolphins
Authors: Bazúa-Durán Carmen
Published: April 2005

Several methods have been used to compare the whistles produced by dolphins. The two methods used in this study are: (1) a classification of whistle contours in six categories (i.e. constant frequency, upsweep, downsweep, concave, convex, and sine) and (2) the extraction of frequency and time parameters from each whistle contour. Bottlenose Dolphin Tursiops truncatus whistles are described in the same way when comparing whistle contour distributions in each of the six categories and whistle frequency and time parameters using Discriminant Function Analysis. For Spinner Dolphin Stenella longirostris whistles, each method describes whistles differently. Several facts may explain these differences in describing dolphin whistles, such as a greater fluidity of Spinner Dolphin groups when compared to Bottlenose Dolphin groups, greater geographic variation in the whistles of Bottlenose Dolphins than in those of Spinner Dolphins, an average beginning frequency 16% lower than the average ending frequency in Spinner Dolphin whistles compared to a varied relationship for Bottlenose Dolphins, and stricter criteria used to define whistle contour categories in the study of Spinner Dolphin whistles than in the Bottlenose Dolphin whistle study.
Communication by unvoiced speech: the role of whispering
Authors: Cirillo Jasmin
Published: April 2005

Most studies on whispering deal with its production and perception, neglecting its communicative role. I have focused on this, especially some social and psychobiological objectives. I have combined a general inquiry into the use of unvoiced speech with stimulus-response experiments on particular signal properties. (1) Analyses of answers to queries revealed that judgments about whispering depend on the social contexts. In the private domain it plays a clearly positive role, but in the public domain it is more problematical. Two causative factors were identified as relevant: (a) an 'ingroup' function of whispering which could induce negative 'outgroup' effects in co-listeners, and (b) a psychobiological component of whispering which could affect the auditory vigilance of co-listeners who were not addressed personally by the signaling, but often wanted to understand a whispered message. (2) Analyses of experimental data confirmed the relevance of these factors. Additionally, they showed that unvoiced speech has a limited transmission range, and is easily masked by background noise. Taken together, the results suggest that whispering is explained best as a close-distance signal adapted for private use among partners.
The T-cell anergy induced by Leishmania amazonensis antigens is related with defective antigen presentation and apoptosis
Authors: Pinheiro Roberta O. , Pinto Eduardo F. , Benedito Alessandra B. , Lopes Ulisses G. , Rossi-Bergmann Bartira
Published: April 2005

Leishmania amazonensis is the main agent of diffuse cutaneous leishmaniasis, a disease associated with anergic immune responses. In this study we show that the crude antigen of Leishmania amazonensis (LaAg) but not L. braziliensis promastigotes (LbAg) contains substances that suppress mitogenic and spontaneous proliferative responses of T cells. The suppressive substances in LaAg are thermoresistant (100ºC/1h) and partially dependent on protease activity. T cell anergy was not due to a decreased production of growth factors as it was not reverted by addition of exogenous IL-2, IL-4, IFN-gamma or IL-12. LaAg did not inhibit anti-CD3-induced T cell activation, suggesting that anergy was due to a defect in antigen presentation. It was also not due to cell necrosis, but was accompanied by expressive DNA fragmentation in lymph node cells, indicative of apoptosis. Although pre-incubation of macrophages with LaAg prevented their capacity to present antigens, this effect was not due to apoptosis of the former. These results suggest that the T cell anergy found in diffuse leishmaniasis may be the result of parasite antigen-driven apoptosis of those cells following defective antigen presentation.
Pollen record and paleoenvironment of a 4210 years B.P.old sediment in the Bay of Guanabara, Rio de Janeiro, Brazil
Authors: Barth Ortrud M. , Barreto Cíntia F. , Coelho Luciane G. , Luz Cynthia F.P.
Published: April 2005

Pollen analysis of a sediment sample obtained at 222 cm from the top of a drilling core collected in the Bay of Guanabara, Rio de Janeiro, was used as a tool to obtain more knowledge about pre-historical human living and environment. 14C datation revealed the age of 4210 years B.P. Most frequent pollen grains came from plants like Alchornea (Euphorbiaceae), Celtis (Ulmaceae), Lecythidaceae, Meliaceae, Ochnaceae and spores from forest Pteridophyta. Palynology and environmental studies revealed that agricultural activities could not be detected. The dense tropical rain forest was the dominant vegetation occurring in this region.
Improving methods for epidemiological control of canine visceral leishmaniasis based on a mathematical model. Impact on the incidence of the canine and human disease
Authors: Palatnik-de-Sousa Clarisa B. , Batista-de-Melo Leopoldina M. , Borja-Cabrera Gulnara P. , Palatnik Marcos , Lavor Carlile C.
Published: April 2005

The mathematical model described by Dye (1996) condemned the epidemiological canine visceral leishma-niasis control campaign, considering it non-efficient. Using this model, we mathematically demonstrate that the control is not efficient, only at low values (rate at which latent and infectious dogs are lost by the destruction program) which match the canine seropositivity observed in the field by the immunofluorescency (IF) blood eluates analysis. With higher k values, corresponding to IF (k = 0.07) or ELISA ( k = 0.25) results in sera samples, the number of infectious dogs declines to a Ro =1 or Ro =0, respectively, interrupting the transmission and the advancement of epidemics. We also experimentally demonstrate that the dog removal, following the results of IF of sera, instead of eluates lead to a 57% (p < 0.005) decrease in canine cases and 87.5% (p < 0.005) in human cases. Our mathematical and experimental results indicate that the control campaign become more efficient by enhancing the sensitivity of the diagnostic assay.
A critical evaluation of coastal erosion in Rio Grande do Sul, Southern Brazil
Authors: Dillenburg Sérgio R. , Esteves Luciana S. , Tomazelli Luiz J.
Published: April 2005

Evidences of coastal erosion in Rio Grande do Sul have been obtained by three methods: (a) analysis of the long-term morphodynamics and stratigraphy of coastal barriers, (b) annual shoreline mapping using the Differential Global Positioning System (DGPS), and (c) local beach profile measurements. The first method reflects coastal erosion as continuity of the geological evolution in the last 5 ka, taking place mainly along the southern half of gentle coastal projections. The second method represents a shorter temporal scale and indicates that approximately 80% of the coast is eroding. Beach profiling has been measured in very few places that are distant from each other since the early 1990s; consequently, their results reflect local and very short time shoreline behavior. A critical evaluation of published data addressing coastal erosion in Rio Grande do Sul strongly suggests that short and long term negative balance on the sediment budget is the main cause of erosion along this coastline.
On the geographical differentiation of Gymnodactylus geckoides Spix, 1825 (Sauria, Gekkonidae): speciation in the Brasilian caatingas
Authors: Vanzolini Paulo Emilio
Published: April 2005

The specific concept of G. geckoides was initially ascertained based on a topotypical sample from Salvador, Bahia. Geographic differentiation was studied through the analysis of two meristic characters (tubercles in a paramedian row and fourth toe lamellae) and color pattern of 327 specimens from 23 localities. It is shown that the population from the southernmost locality, Mucugê, is markedly divergent in all characters studied. A Holocene refuge model is proposed to explain the pattern. A decision about the rank to be attributed to the Mucugê population is deferred until more detailed sampling is effected and molecular methods are applied.
Clinical and laboratory aspects of common variable immunodeficiency
Authors: Kokron Cristina M. , Errante Paolo R. , Barros Myrthes T. , Baracho Gisele V. , Camargo Maristela M. , Kalil Jorge , Rizzo Luiz V.
Published: April 2005

Common variable immunodeficiency (CVID) is an immunological disorder characterized by defective antibody production, recurrent infections, most notably of the respiratory tract, autoimmune phenomena and cancer. Some CVID patients may also present disturbances of the cellular immune response such as a decrease in the number and proportion of different lymphocyte populations, diminished lymphoproliferative response to mitogens and antigens, altered production of cytokines, and deficient expression of cell-surface molecules. Most Brazilian CVID patients included in this study show a decrease in T and B lymphocyte counts in the peripheral blood. Furthermore, their lymphocytes are more susceptible to apoptosis following activation than normal individuals, and they have a decrease in the expression of activation molecules like CD25, CD69, CD40L and CD70. Moreover, they show a decreased synthesis of IL-4 and IL-5 in comparison with normal individuals. The increase in susceptibility to apoptosis following activation, may also be responsible for the decrease in the expression of activation molecules and CD40L, decrease in Th2 cytokines synthesis, and in the number of T and B circulating cells. In this study we discuss some of these immunological disturbances correlating them to the patients' clinical features and comparing our patients' findings to the literature.
Solvent-related chronic toxic encephalopathy as a target in the worker's mental health research
Authors: Ramos Andréia , Jardim Silvia R. , Silva Filho João F.
Published: April 2005

The article is aimed at discussing the theoretical grounds which support the diagnosis of solvent-related chronic encephalopathy in the field of the worker's mental health, having it as a target in this area. The psychiatric, neurological and labor health postulates which contribute to the multidisciplinary description of such diagnostic category are presented.
[NO TITLE AVAILABLE]
Authors: Mazali Italo O. , Alves Oswaldo L.
Published: April 2005

High fidelity calcium carbonate and hydroxyapatite (bio) inorganic replicas of the fibrous network of the dried fruit of Luffa cylindrica are described, utilizing a facile synthetic route. The loofa sponge is a highly complex macroscopic architectural template, an inexpensive and sustainable resource. In the context of the morphosynthesis, the capability of replication of the loofa sponge opens the possibility of the use of biodiversity in obtaining new materials. We would like to emphasize that the template proposed in this paper, makes possible the preparation of inorganic replicas with a very desirable size, on the centimeter scale. This fact is innovative with respect to inorganic replicas described in the literature, which predominate at the micrometric scale, limited to the original size of the template.
A reassessment of the role of serotonergic system in the control of feeding behavior
Authors: Medeiros Magda A. , Costa-e-Sousa Ricardo H. , Olivares Emerson L. , Côrtes Wellington S. , Reis Luís C.
Published: April 2005

The role of serotonergic system in the feeding behaviorwas appraised by electrolytic lesions in the dorsal raphe nucleus (DRN) and administration of para-chlorophenylalanine (PCPA, 3 mg/5 mul, icv). Chronic evaluations were accomplished through 120 and 360 days in PCPA-injected and DRN-lesioned rats, respectively. Acute food intake was evaluated in fasted rats and submitted to injection of PCPA and hydroxytryptophan (LHTP, 30 mg/kg, ip). DRN-lesioned rats exhibited 22-80% increase in food intake up to sixth month, whereas the obesity was evident and sustained by whole period. In PCPA-injected rats was observed an initial increase in the food intake followed by hypophagy from 25th to 30th day and a transitory increase of body weight from 5th to 60th day. In the acute study, the LHTP reverted partially the PCPA-induced increase in food intake of fasted rats suggesting a sustained capacity of decarboxylation of precursor by serotonergic neurons. Slow restoration of the levels of food intake in DRN-lesioned rats reveals a neuroplasticity in the systems that regulate feeding behavior. A plateau on the body weight curve in lesioned rats possibly represents the establishment of a new and higher set point of energetic balance.
Titelbild: Self‐Assembly and Cross‐Linking of Bionanoparticles at Liquid–Liquid Interfaces (Angew. Chem. 16/2005)
Authors: Russell Justin T. , Lin Yao , Böker Alexander , Su Long , Carl Philippe , Zettl Heiko , He Jinbo , Sill Kevin , Tangirala Ravisubhash , Emrick Todd , Littrell Kenneth , Thiyagarajan Pappannan , Cookson David , Fery Andreas , Wang Qian , Russell Thomas P.
Published: April 2005

Die Grenzflächenaktivität des Augenbohnen‐Mosaikvirus (CPMV) zwischen zwei nichtmischbaren Flüssigkeiten wird mithilfe der Fluoreszenzmarkierung untersucht. Das Titelbild zeigt ein Bänderdiagramm von CPMV, fluoreszenzmikroskopische Bilder von Perfluordecalintropfen in Wasser, die von CPMV‐Schichten umgeben sind, und die Struktur eines mit einem fluoreszierenden Farbstoff und Biotin markierten CPMV‐Partikels. In ihrer Zuschrift auf S. 2472 ff. beschreiben T. P. Russell et al. die Bildung robuster Membranen durch Selbstorganisation von CPMV‐Bionanopartikeln an Flüssig‐flüssig‐Grenzflächen.