bluuebunny/crossref_metadata_2025 huggingface dataset:
The role of syntax in encoding and recall of pictorial narratives: Evidence from specific language impairment
Authors: Bishop Dorothy , Donlan Chris
Published: April 2005

Previous research on typically developing children has shown that their memory for events depends on how they are encoded. As children grow older, they start to mention causal and temporal relationships between events, including psychological causes. Children with specific language impairment (SLI) were studied to disentangle the effects of syntactic skill and non‐verbal IQ on event encoding and recall. Children with receptive SLI (SLI‐R;N=34) had a significant discrepancy between non‐verbal IQ and scores on a receptive language measure. Those with expressive SLI (SLI‐E;N=29) did not have significant receptive impairment, but had low scores on at least one expressive language test. Controls were 32 typically developing children of similar age and non‐verbal IQ. Children were shown two sequences of photographs, and in each case, were asked first to describe the story, and then, without warning, to recall it after a delay of 30–40 minutes. Compared with controls, children with SLI recalled significantly less story material. For the SLI‐E group, poor recall was totally accounted for by poor initial encoding of the story content. However, for the SLI‐R group, story memory was poor even after adjusting for amount of information in the initial narrative. Description and recall of the story ideas were related to use of complex syntax, and failure to use cognitive state terms predicted poor recall. We conclude that use of complex syntax and causal concepts are more important than non‐verbal IQ in determining children's event memory.
Marketing Mass-Customized Products: Striking a Balance between Utility and Complexity
Authors: Dellaert Benedict G.C. , Stremersch Stefan
Published: April 2005

Increasingly, firms allow consumers to mass customize their products. In this study, the authors investigate consumers' evaluations of different mass customization configurations when they are asked to mass customize a product. For example, mass customization configurations may differ in the number of modules that can be mass customized. In the context of mass customization of personal computers, the authors find that mass customization configuration affects the product utility that consumers can achieve in mass customization as well as their perception of mass customization complexity. In turn, product utility and complexity affect the utility that consumers derive from using a certain mass customization configuration. More specifically, product utility has a positive effect and complexity has a negative effect on mass customization utility. The effect of complexity is direct as well as indirect because complexity also lowers product utility. The authors also find that consumers with high levels of product expertise consider mass customization configurations less complex than do consumers with low levels of product expertise and that for more-expert consumers, complexity has a less-negative impact on product utility. The study has important managerial implications for how companies can design their mass customization configuration to increase utility and decrease complexity.
TrkB Has a Cell-Autonomous Role in the Establishment of Hippocampal Schaffer Collateral Synapses
Authors: Luikart Bryan W. , Nef Serge , Virmani Tuhin , Lush Mark E. , Liu Yajuan , Kavalali Ege T. , Parada Luis F.
Published: April 2005

Neurotrophin signaling has been implicated in the processes of synapse formation and plasticity. To gain additional insight into the mechanism of BDNF and TrkB influence on synapse formation and synaptic plasticity, we generated a conditional knock-out for TrkB using thecre/loxpsystem. Using three different cre-expressing transgenic mice, three unique spatial and temporal configurations of TrkB deletion were obtained with regard to the hippocampal Schaffer collateral synapse. We compare synapse formation in mutants in which TrkB is ablated either in presynaptic or in both presynaptic and postsynaptic cells at early developmental or postdevelopmental time points. Our results indicate a requirement for TrkB at both the presynaptic and postsynaptic sites during development. In the absence of TrkB, synapse numbers were significantly reduced.In vivoablation of TrkB after synapse formation did not affect synapse numbers. In primary hippocampal cultures, deletion of TrkB in only the postsynaptic cell, before synapse formation, also resulted in deficits of synapse formation. We conclude that TrkB signaling has a cell-autonomous role required for normal development of both presynaptic and postsynaptic components of the Schaffer collateral synapse.
Phase Synchrony among Neuronal Oscillations in the Human Cortex
Authors: Palva J. Matias , Palva Satu , Kaila Kai
Published: April 2005

Synchronization of neuronal activity, often associated with network oscillations, is thought to provide a means for integrating anatomically distributed processing in the brain. Neuronal processing, however, involves simultaneous oscillations in various frequency bands. The mechanisms involved in the integration of such spectrally distributed processing have remained enigmatic. We demonstrate, using magnetoencephalography, that robust cross-frequency phase synchrony is present in the human cortex among oscillations with frequencies from 3 to 80 Hz. Continuous mental arithmetic tasks demanding the retention and summation of items in the working memory enhanced the cross-frequency phase synchrony among α (∼10 Hz), β (∼20 Hz), and γ (∼30-40 Hz) oscillations. These tasks also enhanced the “classical” within-frequency synchrony in these frequency bands, but the spatial patterns of α, β, and γ synchronies were distinct and, furthermore, separate from the patterns of cross-frequency phase synchrony. Interestingly, an increase in task load resulted in an enhancement of phase synchrony that was most prominent between γ- and α-band oscillations. These data indicate that cross-frequency phase synchrony is a salient characteristic of ongoing activity in the human cortex and that it is modulated by cognitive task demands. The enhancement of cross-frequency phase synchrony among functionally and spatially distinct networks during mental arithmetic tasks posits it as a candidate mechanism for the integration of spectrally distributed processing.
Identification of Genes Involved in Synaptogenesis Using a Fluorescent Active Zone Marker inCaenorhabditis elegans
Authors: Yeh Edward , Kawano Taizo , Weimer Robby M. , Bessereau Jean-Louis , Zhen Mei
Published: April 2005

Active zones are presynaptic regions where synaptic vesicles fuse with plasma membrane to release neurotransmitters. Active zones are highly organized structurally and are functionally conserved among different species. Synapse defective-2 (SYD-2) family proteins regulate active zone morphology inCaenorhabditis elegansandDrosophila. Here, we demonstrate by immunoelectron microscopy that atC. eleganssynapses, SYD-2 localizes strictly at active zones and can be used as an active zone marker when fused to green fluorescent protein (GFP). By driving expression of SYD-2::GFP fusion protein in GABAergic neurons, we are able to visualize discrete fluorescent puncta corresponding to active zones in livingC. elegans. During development, the number of GABAergic synapses made by specific motoneurons increases only slightly from larvae to adult stages. In contrast, the number of SYD-2::GFP puncta doubles, suggesting that individual synapses accommodate the increasing size of their synaptic targets mainly by incorporating more active zone materials. Furthermore, we used this marker to perform a genetic screen to identify genes involved in the development of active zones. We recovered 16 mutants with altered SYD-2::GFP expression, including alleles of five genes that have been implicated previously in synapse formation or nervous-system development. Mapping of 11 additional mutants suggests that they may represent novel genes involved in active zone formation.
cAMP-Mediated Mechanisms for Pain Sensitization during Opioid Withdrawal
Authors: Bie Bihua , Peng Yi , Zhang Yong , Pan Zhizhong Z.
Published: April 2005

Chronic opioid-induced drug dependence and withdrawal syndrome after opioid cessation remain a severe obstacle in clinical treatment of chronic pain and opioid drug addiction. One of the key symptoms during opioid withdrawal is a state of sensitized pain. The most significant molecular adaptation induced by chronic opioids in the brain is upregulation of the cAMP-signaling pathway. Although the cAMP system is known to have multiple effects on central neuron functions, how its upregulation mediates behavioral opioid dependence and withdrawal-induced painin vivoremains unclear. In this study, we demonstrate that withdrawal from chronic morphine significantly upregulates the mRNA level of adenylyl cyclase (AC) VI and VIII isoforms and immunoreactivity of ACV/VI in the nucleus raphe magnus (NRM), a brainstem site critically involved in opioid modulation of pain. In cellular studies of NRM neurons containing μ-opioid receptors, we show that morphine withdrawal significantly increases glutamate synaptic transmission via a presynaptic mechanism mediated by an upregulated cAMP pathway. Morphine withdrawal also enhances the hyperpolarization-activated current in these neurons by increased intracellular cAMP. Both of the withdrawal-induced cAMP actions increase the excitability of these μ-receptor-containing neurons, which are thought to facilitate spinal pain transmission. Furthermore, in morphine-dependent ratsin vivo, blocking the cAMP pathway significantly reduces withdrawal-induced pain sensitization. These results illustrate neurobiological mechanisms for the cAMP-mediated withdrawal pain and provide potential therapeutic targets for the treatment of opioid dependence and withdrawal-related problems.
Petrography and mineral chemistry of carbonatites and mica-rich rocks from the Araxá complex (Alto Paranaíba Province, Brazil)
Authors: TRAVERSA GIANBOSCO , GOMES CELSO B. , BROTZU PIERO , BURAGLINI NICOLETTA , MORBIDELLI LUCIO , PRINCIPATO MARIA SPERANZA , RONCA SARA , RUBERTI EXCELSO
Published: April 2005

The Araxá complex (16 km²) comprises carbonatites forming a central core and a complex network of concentric and radial dykes as well as small veins; additionally, it includes mica-rich rocks, phoscorites and lamprophyres. Fenites also occur and are represented by Proterozoic quartzites and schists of the Araxá Group. The petrographic study of 130 borehole samples indicates that the complex is basically made up by two rock-types, carbonatites and mica-rich rocks, and subordinately by a third unit of hybrid composition. Carbonatites range chemically in composition, the most abundant type being magnesiocarbonatites. Dolomite and calcite correspond to the chief constituents, but other carbonate phases, including the Ce-group RE minerals, are also recognized. Phosphates and oxides are widespread accessories whereas silicate minerals consist of olivine, clinopyroxene, mica and amphibole. Mica-rich rocks are represented by abundant glimmeritic rocks and scarce cumulitic phlogopite-, olivine- and diopside-bearing pyroxenites. Hybrid rocks mainly contain phlogopite and tetraferriphlogopite as cumulus and intercumulus phases, respectively; carbonate minerals may also be found. Chemical data indicate that the carbonatites are strongly enriched in REE and have lower contents of Nb, Zr, V, Cr, Ni and Rb compared to the mica-rich rocks. The higher K, Nb and Zr contents of the latter rocks are believed to be related to metasomatic processes (glimmeritization) of the pyroxenites. Similar REE patterns for carbonatites and mica-rich rocks seem to suggest that they are related to a single parental magma, possibly of ijolitic composition. Steep LREE/HREE fractionation and high sigmaREE content of some carbonatite samples would be explained by hydrothermal and supergenic processes.
Response of the brain to enrichment
Authors: DIAMOND MARIAN C.
Published: April 2005

Before 1960, the brain was considered by scientists to be immutable, subject only to genetic control. In the early sixties, however, investigators were seriously speculating that environmental influences might be capable of altering brain structure. By 1964, two research laboratories proved that the morphology and chemistry or physiology of the brain could be experientially altered (Bennett et al. 1964, Hubel and Wiesel 1965). Since then, the capacity of the brain to respond to environmental input, specifically "enrichment,'' has become an accepted fact among neuroscientists, educators and others. In fact, the demonstration that environmental enrichment can modify structural components of the rat brain at any age altered prevailing presumptions about the brain's plasticity (Diamond et al. 1964, Diamond 1988). The cerebral cortex, the area associated with higher cognitive processing, is more receptive than other parts of the brain to environmental enrichment. The message is clear: Although the brain possesses a relatively constant macrostructural organization, the ever-changing cerebral cortex, with its complex microarchitecture of unknown potential, is powerfully shaped by experiences before birth, during youth and, in fact, throughout life. It is essential to note that enrichment effects on the brain have consequences on behavior. Parents, educators, policy makers, and individuals can all benefit from such knowledge.
Watery and dark axons in Wallerian degeneration of the opossum's optic nerve: different patterns of cytoskeletal breakdown?
Authors: NARCISO MARCELO S. , HOKOÇ JAN NORA , MARTINEZ ANA M. B.
Published: April 2005

In this paper we report a qualitative morphological analysis of Wallerian degeneration in a marsupial. Right optic nerves of opossums Didelphis marsupialis were crushed with a fine forceps and after 24, 48, 72, 96 and 168 hours the animals were anaesthetized and perfused with fixative. The optic nerves were immersed in fixative and processed for routine transmission electron microscopy. Among the early alterations typical of axonal degeneration, we observed nerve fibers with focal degeneration of the axoplasmic cytoskeleton, watery degeneration and dark degeneration, the latter being prevalent at 168 hours after crush. Our results point to a gradual disintegration of the axoplasmic cytoskeleton, opposed to the previous view of an "all-or-nothing'' process (Griffin et al 1995). We also report that, due to an unknown mechanism, fibers show either a dark or watery pattern of axonal degeneration, as observed in axon profiles. We also observed fibers undergoing early myelin breakdown in the absence of axonal alterations.
The tides and tidal circulation of Todos os Santos Bay, Northeast Brazil: a general characterization
Authors: LESSA GUILHERME C. , DOMINGUEZ JOSÉ M. L. , BITTENCOURT ABÍLIO C.S.P. , BRICHTA ARNO
Published: April 2005

The Todos os Santos Bay, located on northeastern Brazil, is the second largest coastal bay in the country, after São Marcos Bay. The three main drainage basins convey an average of 120 m³/s of freshwater towards the bay, the majority of it, however, held by a dam in Paraguaçu River since 1985. The original average freshwater inflow was two orders of magnitude smaller than the estimated tidal discharge through the main bay entrance, and the oceanographic characteristics of the bay, as indicated by bay salinity measurements, are clearly marine. The tides are semi-diurnal, and are amplified up the bay by a factor of 1.5. Shallow water constituents become more important as the tide propagates along Paraguaçu Channel and Paraguaçu River, where they generate time asymmetries that change between spring and neap tides. Currents in the bay are mainly bi-directional, and are stronger during the ebbing tide in most of the bay. Offshore, relatively strong tidal currents appear to be felt in a radius of about 10 km, where they are superimposed on winds driven currents orientated to the southwest.
The Barreiras Group in the Northeastern coast of the State of Bahia, Brazil: depositional mechanisms and processes
Authors: VILAS BÔAS GERALDO S. , SAMPAIO FLÁVIO J. , PEREIRA ANTONIO M. S.
Published: April 2005

The Barreiras Group is a Miocene to Lower Pleistocene continental terrigenous sedimentary deposit exhibiting a large occurrence along the Brazilian coast. In the Conde region, located in the northeastern part of the State of Bahia, the sedimentological characteristics of these sediments are indicative of a deposition as gravelly and sandy bed load in braided fluvial systems, related to alluvial fans, under an arid to semi-arid climate. The basal portion of the group is dominated by a gravelly-sandy lithofacies deposited by debris flows and pseudoplastic debris flows, with lesser occurrences of subaqueous deposits, characterizing a proximal fluvial system deposition. The upper portion is made up of gravelly-sandy sediments that include subaqueous, debris flows and pseudoplastic debris flows deposits. They suggest deposition in a more distal zone as indicated by the larger occurrence of subaqueous deposits and the presence, though rare, of downstream-accretion macroforms. Besides the climate control, deposition of the Barreiras Group was strongly influenced by the intraplate tectonism, which has been affecting the South America Platform since the Middle Miocene, when neotectonism began in Brazil.
Apparent resistivity and spectral induced polarization in the submarine environment
Authors: SOUZA HERCULES DE , SAMPAIO EDSON E. S.
Published: April 2005

Relatively few investigations have employed electrical methods in the submarine environment, which may be promising for mineral deposits or threatened by environmental problems. We have measured the electric field using both disk and bar electrodes in the sea water at three different levels: sea surface, seven meters deep, and sea bottom at a depth of ten meters, employing a 2 m spacing dipole-dipole array with 7 array spacings of investigation, and 13 values of frequencies at steps of (2N hertz, N = -2, -1, 0, 1, 2,.....10). The measurement allowed the analysis of the electric field as a function of frequency and spacing, and of the spectral induced polarization. Modelling and interpretation of the apparent resistivity yielded a good fit with previous drilling data. Analysis of the spectrum of the complex apparent resistivity and the comparison with equivalent circuits, provided information about the grain size, the mineral composition and the major induced polarization phenomenon occurring below the sea. Therefore the result of the present research show the feasibility of measuring the variation of seawater resistivity in situ, as well as the resistivity of sea bottom sediments.
The neural crest stem cells: control of neural crest cell fate and plasticity by endothelin-3
Authors: DUPIN ELISABETH , REAL CARLA , LeDOUARIN NICOLE
Published: April 2005

How the considerable diversity of neural crest (NC)-derived cell types arises in the vertebrate embryo has long been a key question in developmental biology. The pluripotency and plasticity of differentiation of the NC cell population has been fully documented and it is well-established that environmental cues play an important role in patterning the NC derivatives throughout the body. Over the past decade, in vivo and in vitro cellular approaches have unravelled the differentiation potentialities of single NC cells and led to the discovery of NC stem cells. Although it is clear that the final fate of individual cells is in agreement with their final position within the embryo, it has to be stressed that the NC cells that reach target sites are pluripotent and further restrictions occur only late in development. It is therefore a heterogenous collection of cells that is submitted to local environmental signals in the various NC-derived structures. Several factors were thus identified which favor the development of subsets of NC-derived cells in vitro. Moreover, the strategy of gene targeting in mouse has led at identifying new molecules able to control one or several aspects of NC cell differentiation in vivo. Endothelin peptides (and endothelin receptors) are among those. The conjunction of recent data obtained in mouse and avian embryos and reviewed here contributes to a better understanding of the action of the endothelin signaling pathway in the emergence and stability of NC-derived cell phenotypes.
Constant mean curvature one surfaces in hyperbolic 3-space using the Bianchi-Calò method
Authors: LIMA LEVI L. DE , ROITMAN PEDRO
Published: April 2005

In this note we present a method for constructing constant mean curvature on surfaces in hyperbolic 3-space in terms of holomorphic data first introduced in Bianchi's Lezioni di Geometria Differenziale of 1927, therefore predating by many years the modern approaches due to Bryant, Small and others. Besides its obvious historical interest, this note aims to complement Bianchi's analysis by deriving explicit formulae for CMC-1 surfaces and comparing the various approaches encountered in the literature.
Structure and anticoagulant properties of sulfated glycosaminoglycans from primitive Chordates
Authors: PAVÃO MAURO S. G.
Published: April 2005

Dermatan sulfates and heparin, similar to the mammalian glycosaminoglycans, but with differences in the degree and position of sulfation were previously isolated from the body of the ascidian Styela plicata and Ascidia nigra. These differences produce profound effects on their anticoagulant properties. S. plicata dermatan sulfate composed by 2-O-sulfatedalpha-L-iduronic acid and 4-O-sulfated N-acetyl-beta-D-galactosamine residues is a potent anticoagulant due to a high heparin cofactor II activity. Surprisingly, it has a lower potency to prevent thrombus formation on an experimental model and a lower bleeding effect in rats than the mammalian dermatan sulfate. In contrast, A. nigra dermatan sulfate, also enriched in 2-O-sulfated alpha-L-iduronic acid, but in this case sulfated at O-6 of the N-acetyl-beta-D-galactosamine units, has no in vitro or in vivo anticoagulant activity, does not prevent thrombus formation but shows a bleeding effect similar to the mammalian glycosaminoglycan. Ascidian heparin, composed by 2-O-sulfated alpha-L-iduronic acid, N- and 6-O-sulfated glucosamine (75%) and alpha-L-iduronic acid, N- and 6-O-sulfated glucosamine (25%) disaccharide units has an anticoagulant activity 10 times lower than the mammalian heparin, is about 20 times less potent in the inhibition of thrombin by antithrombin, but has the same heparin cofactor II activity as mammalian heparin.
Periodic perturbations of quadratic planar polynomial vector fields
Authors: MESSIAS MARCELO
Published: April 2005

In this work are studied periodic perturbations, depending on two parameters, of quadratic planar polynomial vector fields having an infinite heteroclinic cycle, which is an unbounded solution joining two saddle points at infinity. The global study envolving infinity is performed via the Poincaré compactification. The main result obtained states that for certain types of periodic perturbations, the perturbed system has quadratic heteroclinic tangencies and transverse intersections between the local stable and unstable manifolds of the hyperbolic periodic orbits at infinity. It implies, via the Birkhoff-Smale Theorem, in a complex dynamical behavior of the solutions of the perturbed system, in a finite part of the phase plane.
Molecular variability in Amerindians: widespread but uneven information
Authors: SALZANO FRANCISCO M.
Published: April 2005

A review was made in relation to the molecular variability present in North, Central, and South American Indian populations. It involved results from ancient DNA, mitochondrial DNA in extant populations, HLA and other autosomal markers, X and Y chromosome variation, as well as data from parasitic viruses which could show coevolutionary changes. The questions considered were their origin, ways in which the early colonization of the continent took place, types and levels of the variability which developed, peculiarities of the Amerindian evolutionary processes, and eventual genetic heterogeneity which evolved in different geographical areas. Although much information is already available, it is highly heterogeneous in relation to populations and types of genetic systems investigated. Unfortunately, the present trend of favoring essentially applied research suggest that the situation will not basically improve in the future.
Physiopathological modulators of amyloid aggregation and novel pharmacological approaches in Alzheimer's disease
Authors: DEFELICE FERNANDA G. , FERREIRA SÉRGIO T.
Published: April 2005

The biological mechanisms underlying the neuropathology of Alzheimer's disease (AD) are complex, as several factors likely contribute to the development of the disease. Therefore, it is not surprising that a number of different possible therapeutic approaches addressing distinct aspects of this disease are currently being investigated. Among these are ways to prevent amyloid aggregation and/or deposition, to prevent neuronal degeneration, and to increase brain neurotransmitter levels. Here, we discuss possible roles of endogenous modulators of Abeta aggregation in the physiopathology of AD and some of the strategies currently under consideration to interfere with brain levels of beta-amyloid, its aggregation and neurotoxicity.
Chemical constituents of Simarouba versicolor
Authors: ARRIAGA ANGELA M.C. , MESQUITA ALDENOR C. DE , POULIQUEN YVONE B.M. , LIMA ROBERTO A. DE , CAVALCANTE SERGIO H. , CARVALHO MARIO G. DE , SIQUEIRA JOSÉ A. DE , ALEGRIO LEILA V. , BRAZ-FILHO RAIMUNDO
Published: April 2005

From the roots, stems and fruits of Simarouba versicolor (Simaroubaceae) were isolated quassinoids (3, 5-7), triterpenoids (8-14), a mixture of steroids (15-17), the flavonoid kaempferol (18) and the squalene derivative 11,14-diacetoxy-7,10; 15,18-diepoxy-6,19-dihidroxy-6,7,10,11,14,15,18,19-octahydrosqualene (19). Spectral data were used for structural characterization.
The application of catalase for the elimination of hydrogen peroxide residues after bleaching of cotton fabrics
Authors: AMORIM ALEXANDRA M. , GASQUES MARCELO D. G. , ANDREAUS JÜRGEN , SCHARF MAURO
Published: April 2005

Results of dyeing of cotton fabrics with a bifunctional reactive dye were significantly improved when the fabric after bleaching with hydrogen peroxide was treated with catalase for the elimination of hydrogen peroxide residues from the fabrics. Compared to processes with a varying number of washing steps, with and without commercial reducing agents, the consumption of water could be significantly reduced, without altering the final color shade.
On the squamation of Australerpeton cosgriffi Barberena, a temnospondyl amphibian from the Upper Permian of Brazil
Authors: DIAS ELISEU V. , RICHTER MARTHA
Published: April 2005

Abdominal scales of a juvenile specimen of Australerpeton cosgriffi Barberena 1998 are made of primary compact bone rich in osteocyte lacunae; vascular canals and primary osteons are rare with no sign of remodelling of the tissue by resorption and redeposition. In contrast, the abdominal scales of an adult of the same species shows extensive reworking of the bone tissue. The scale grows by apposition of lamellar bone peripherally around the whole scale; the presence of Sharpey fibers in the periphery of the scales both basally and externally suggests that they remained deeply embedded in the dermis; the embryonic scale is completely remodelled in the adult by resorption and redeposition which produces a cancellous bone with large erosion bays and secondary osteons. Remodelling by resorption and redeposition is confined to the core of the scales and does not affect its periphery, contrary to what happens in sarcopterygians with cosmoid scales. The possible biological functions of the squamation in this species, such as mechanical protection, dry protection, cutaneous respiration, hydrostatic control and calcium reservoir, are discussed.
A significant longshore transport divergence zone at the Northeastern Brazilian coast: implications on coastal Quaternary evolution
Authors: BITTENCOURT ABÍLIO C.S.P. , MARTIN LOUIS , DOMINGUEZ JOSÉ M.L. , SILVA IRACEMA R. , SOUSA DAIANA L.
Published: April 2005

By using the mean directions of the wave-fronts approaching the Brazilian northeastern coastal stretch comprised between the localities of Real river (Sergipe State) and Galinhos (Rio Grande do Norte State) - coincident with those of the main winds occurring in the area - and their periods, we have defined a wave climate model based on the construction of refraction diagrams. The resulting model of sediment transport, as obtained by numerical modelling from the refraction diagrams, taking into consideration the angle of approach and waves heights along the 10-m isobath, was capable of reproducing the patterns of sediment dispersion provided by geomorphic indicators of the longshore drift. All this coastal region, approximately 900 km in length, is characterized by a significant divergence zone in the direction of net longshore drift of sediments, the potential intensity of which increases considerably in value, in almost its entire length, continuously toward downdrift, which might explain the greater or lesser long term susceptibility to erosion, during the Quaternary, along the coastal stretch studied.
Tectonics and paleogeography of the Marajó Basin, northern Brazil
Authors: COSTA JOÃO B. S. , HASUI YOCITERU , BEMERGUY RUTH L. , SOARES-JÚNIOR ADILSON V. , VILLEGAS JAVIER M. C.
Published: April 2005

The Marajó Basin area presents geologic and geomorphologic features chiefly due to the Mesozoic extension and post-Miocene neotectonics. The extension event with an Early and a Late Cretaceous phases originated four sub-basins that constitutes the Marajó Basin, with a thick continental clastic sequence showing marine influence. NW and NNW normal faults and NE and ENE strike-slip faults controlled the basin geometry. The extension, related to the Equatorial Atlantic opening, propagated into the continent along crustal weakness zones of the Precambrian Tumucumaque, Amapá and Araguaia orogenic belts. The neotectonic event is a strike-slip regime which developed transtensional basins filled in by Upper Tertiary shallow marine (Pirabas Formation) and transitional sequences (Barreiras Group), followed by Quaternary fluvial deposits and transitional sequences derived from the Amazon and Tocantins rivers and the Marajoara estuary. The current landscape has a typical estuarine morphology. The coast morphology presents sea-cliffs on transitional Upper Tertiary sequences, while inwards dominate hills sustained by Mid-Pleistocene lateritic crust, with a flat erosive surface at 70 m. In the eastern Marajó Island several generations of paleochannels associated with fluvial-estuarine sequences are recognized, while a fluvial-marine plain is widespread on its western side.
On Ribaucour transformations and applications to linear Weingarten surfaces
Authors: TENENBLAT KETI
Published: April 2005

We present a revised definition of a Ribaucour transformation for submanifolds of space forms, with flat normal bundle, motivated by the classical definition and by more recent extensions. The new definition provides a precise treatment of the geometric aspect of such transformations preserving lines of curvature and it can be applied to submanifolds whose principal curvatures have multiplicity bigger than one. Ribaucour transformations are applied as a method of obtaining linear Weingarten surfaces contained in Euclidean space, from a given such surface. Examples are included for minimal surfaces, constant mean curvature and linear Weingarten surfaces. The examples show the existence of complete hyperbolic linear Weingarten surfaces in Euclidean space.
Spectral properties and conformal type of surfaces
Authors: CASTILLON PHILIPPE
Published: April 2005

In this short note, we announce a result relating the geometry of a riemannian surface to the positivity of some operators on this surface (the operators considered here are of the form surface Laplacian plus a scalar multiple of the curvature function). In particular we obtain a theorem "à la Huber'': under a spectral hypothesis we prove that the surface is conformally equivalent to a Riemann surface with a finite number of points removed. This problem has its origin in the study of stable minimal surfaces.
A second note on the geographical differentiation of Amphisbaena fuliginosa L., 1758 (Squamata, Amphisbaenidae), with a consideration of the forest refuge model of speciation
Authors: VANZOLINI PAULO EMILIO
Published: April 2005

The geographical differentiation of Amphisbaena fuliginosa L. is studied with basis on 220 specimens from 99 definite and 2 generic localities, ranging from Panamá to Puno in Peru and Goiás in Brasil. The pattern found is considered to support Vanzolini's 1951 scheme of five subspecies, defined by color pattern and by four meristic characters, and differentiated in consequence of Quaternary paleoecological events. Recent developments relating to models of differentiation in Quaternary tropical South America are briefly considered.
Shrimp and conventional U-Pb age, Sm-Nd isotopic characteristics and tectonic significance of the K-rich Itapuranga suite in Goiás, Central Brazil
Authors: PIMENTEL MÁRCIO M. , DANTAS ELTON L. , FUCK REINHARDT A. , ARMSTRONG RICHARD A.
Published: April 2005

The Itapuranga alkali granite and Uruana quartz syenite are large K-rich EW-elongated intrusions, in the central part of the Neoproterozoic Brasília Belt, central Brazil. They are associated with Pireneus lineaments, which cut the regional NNW-SSE structures of the southern part of the belt. SHRIMP and conventional U-Pb data for the Itapuranga and Uruana intrusions indicate crystallization ages of 624 ± 10 Ma and 618 ± 4 Ma, respectively. Three zircon cores from the Itapuranga granite yielded U-Pb ages between 1.79 and 1.49 Ga. Sm-Nd T DM ages for both intrusions are 1.44 Ga and epsilonNd(T) values are -5.1 and -5.7, suggesting the input of material derived from older (Paleo- to Mesoproterozoic) sialic crust in the origin of the parental magmas. Magma mixing structures indicate co-existence of mafic and felsic end-members. The felsic end-member of the intrusions is dominantly represented by crust-derived melts, formed in response to the invasion of Paleo/Mesoproterozoic sialic crust by alkali-rich mafic magmas at ca. 620 Ma. These intrusions are roughly contemporaneous with, or perhaps slightly younger than, the peak of regional metamorphism in the southern Brasília Belt. Their emplacement along the Pireneus lineament suggest a syn-tectonic origin for them, most probably in transtensional settings along these faults.
On the monomial birational maps of the projective space
Authors: Gonzalez-Sprinberg Gérard , Pan Ivan
Published: April 2005

We describe the group structure of monomial Cremona transformations. It follows that every element of this group is a product of quadratic monomial transformations, and geometric descriptions in terms of fans.
Balanced cytokine-producing pattern in mice immunized with an avirulent Trypanosoma cruzi
Authors: Soares Milena B. P. , Gonçalves Renata , Pyrrho Alexandre S. , Costa Deise A. , Paiva Claudia N. , Gattass Cerli R.
Published: April 2005

We have previously demonstrated that inoculation of BALB/c mice with trypomastigotes of CL-14, an avirulent Trypanosoma cruzi clone, prevents the development of parasitemia and mortality after challenge with virulent CL strain. In this report, we investigated the cytokine and antibody profiles induced by inoculation with CL-14 clone. Groups of mice were inoculated with trypomastigotes of CL-14 clone and challenged with infective CL strain. Challenged CL-14-inoculated mice had lower levels of IFN-g and higher production of IgG1 antibodies as compared to CL strain-infected mice. Previous inoculation with CL-14 clone partially prevented the suppression of IL-2 production caused by CL strain infection. No significant differences were found regarding IL-4 production by splenocytes from CL-14-inoculated or control groups after challenge with CL-strain. Our results show that protection against acute T. cruzi infection induced by CL-14 inoculation correlates with a balanced T1/T2 cytokine production, a profile likely to be beneficial for the host.
Araçatuba Formation: palustrine deposits from the initial sedimentation phase of the Bauru Basin
Authors: Fernandes Luiz A. , Giannini Paulo C. F. , Góes Ana Maria
Published: April 2005

The Bauru Basin (Upper Cretaceous) accumulated an essentially sandy continental sedimentary sequence. In a first desertic phase the basaltic substratum was covered by a widespread and homogeneous aeolian sand unit with minor loess intercalations. The substratum relief favored the formation of an endorheic drainage system under semi-arid climate, a process that started the development of the Araçatuba Paleoswamp. The palustrine deposits (Araçatuba Formation) comprise siltstone and tipically greenish gray narrow tabular strata of sandstone cemented by carbonate. Moulds and gypsite and dolomite pseudomorphs were identified. The moulds seem to be genetically associated with desiccation cracks, root marks and climbing ripple lamination levels, that, on the whole, indicate calm shallow saline waters undergoing phases of subaerial exposition. At the boundaries of the study area, sand units may exhibit sigmoidal features and convolute bedding structure, which is characteristic of marginal deltaic deposits. The Araçatuba Formation is enclosed in and later overlaid by the aeolian deposits of the Vale do Rio do Peixe Formation.
Experimental models of 'Basement'-controlled salients - application to the proterozoic fold-thrust belt of the quadrilátero ferrífero (Minas Gerais, Southeastern Brazil)
Authors: Gomes Caroline J. S. , Pereira-Filho Milton , Braga Silvia C. M.
Published: April 2005

Scaled sandbox models are used to simulate the development of ´basement´-controlled, salients. We investigate the controlling factors on the development of closed curvatures in map-view, considering constant both the sand pack thickness and the space between obstacles. These models are compared with the Fundão-Cambotas Fault System in the Proterozoic fold-thrust belt in the Quadrilátero Ferrífero region, along the southeastern margin of the São Francisco craton. In the experiments, a pronounced curvature resulted from the margin-controlled salient process in the presence (i) of a basal ductile detachment, or (ii) of pre-existing structures. The results suggest that the convex-to-the-foreland, west-vergent Fundão-Cambotas Fault System that borders the Archean basement highs and displaced older Transamazonian structures westward, is partly a consequence of interaction of propagating thrusts with obstacles in the foreland.
Lutzomyia longipalpis (Diptera: Psychodidae: Phlebotominae): a review
Authors: Soares Rodrigo P. P. , Turco Salvatore J.
Published: April 2005

Lutzomyia longipalpis is the most important vector of AmericanVisceral Leishmaniasis (AVL) due to Leishmania chagasi in the New World. Despite its importance, AVL, a disease primarily of rural areas, has increased its prevalence and became urbanized in some large cities in Brazil and other countries in Latin America. Although the disease is treatable, other control measures include elimination of infected dogs and the use of insecticides to kill the sand flies. A better understanding of vector biology could also account as one more tool for AVL control. A wide variety of papers about L. longipalpis have been published in the recent past years. This review summarizes our current information of this particular sand fly regarding its importance, biology, morphology, pheromones genetics, saliva, gut physiology and parasite interactions.
Quaternary evolution of the Caravelas strandplain - Southern Bahia State - Brazil
Authors: Andrade Ana C.S. , Dominguez José M.L. , Martin Louis , Bittencourt Abílio C.S.P.
Published: April 2005

An evolutionary model is proposed for the Caravelas strandplain. The model encompasses integration of: (i) mapping of Quaternary deposits, (ii) cartography of beach-ridge alignments and their truncations, (iii) relative sea-level history, (iv) development history of the Abrolhos coral reefs, (v) vibra-coring and (vi) C14 dating of Quaternary deposits. Seven major evolutionary stages were identified. These stages show that the strandplain has had its Quaternary evolution strongly controlled by relative sea-level changes. In addition, the development of the Abrolhos coral reefs has also played an important role in dispersion and accumulation of sediments along the coastline, causing localized inversion in longshore sediment transport.
Epicuticular waxes from caatinga and cerrado species and their efficiency against water loss
Authors: Oliveira Antonio F. M. , Meirelles Sérgio T. , Salatino Antonio
Published: April 2005

The effects of the contents and chemical composition of the foliar epicuticular waxes of species from the caatinga (Aspidosperma pyrifolium, Capparis yco, Maytenus rigida and Ziziphus joazeiro) and cerrado (Aristolochia esperanzae, Didymopanax vinosum, Strychnos pseudoquina and Tocoyena formosa) were evaluated as to the resistance to water loss by means of an experimental device constructed for this purpose. In general, the waxes of the caatinga species investigated were more efficient against water loss than cerrado species. Increase of the thickness of the waxy deposits from 40 to 90m g.cm-2 had no significant effect on the resistance to water loss. The chemistry of the wax constituents was shown to be an important factor to determine the degree of resistance to evaporation. n-Alkanes and alcoholic triterpenes were the most efficient barriers, while hentriacontan-16-one (a ketone) and ursolic acid (an acid triterpene) revealed lowefficiency. The higher efficiency of the waxes of the leaves from caatinga species (mainly those of C. yco and Z. joazeiro) is probably accounted for the predominance of n-alkanes in their composition. The lower efficiency of the waxes of A. pyrifolium (caatinga), T. formosa and A. esperanzae (both species from the cerrado) is probably a consequence of the predominance of triterpenoids in the waxes of the two former species and hentriacontan-16-one in the latter.
The promoting effect of cesium on structure and morphology of silver catalysts
Authors: Carvalho Marta C. N. A. , Perez Carlos A. , Simão Renata A. , Passos Fabio B. , Schmal Martin
Published: April 2005

Silver supported catalysts on alpha-alumina were prepared and characterized by Brunauer-Emmet-Teller equations, scanning electronic microscopy, X-ray diffraction and atomic force microscopy techniques. Results show that these are powerful techniques for the determination of texture, morphology and surface properties. It has been shown that the addition of Cs in the Ag/Al2O3 catalyst increased the dispersion of silver with the formation of small silver particles over a thin silver film already formed over the alumina support. It is important to stress that atomic force microscopy measurements are significant to observe the film and the dispersion of Ag and, on the contrary, X-ray photoelectronic spectroscopy did not, however, it allows to the conclusion that undistinguishable silver, either as metallic or oxidation state, are present at the surface. X-ray diffraction results confirm predominantly metallic silver.
The seed coat of Phaseolus vulgaris interferes with the development of the cowpea weevil [Callosobruchus maculatus (F.) (Coleoptera: Bruchidae)]
Authors: Silva Luciana B. , Sales Maurício P. , Oliveira Antônia E. A. , Machado Olga L. T. , Fernandes Kátia V. S. , Xavier-Filho José
Published: April 2005

We have confirmed here that the seeds of the common bean (Phaseolus vulgaris, L.) do not support development of the bruchid Callosobruchus maculatus (F.), a pest of cowpea [Vigna unguiculata (L.) Walp] seeds. Analysis of the testa (seed coat) of the bean suggested that neither thickness nor the levels of compounds such as tannic acid, tannins, or HCN are important for the resistance. On the other hand, we have found that phaseolin (vicilin-like 7S storage globulin), detected in the testa by Western blotting and N-terminal amino acid sequencing, is detrimental to the development of C. maculatus. As for the case of other previously studied legume seeds (Canavalia ensiformis and Phaseolus lunatus) we suggest that the presence of vicilin-like proteins in the testa of P. vulgaris may have had a significant role in the evolutionary adaptation of bruchids to the seeds of leguminous plants.
Brain serotonin depletion enhances the sodium appetite induced by sodium depletion or beta-adrenergic stimulation
Authors: Lima Hawlinston R. C. , Cavalcante-Lima Haerishton R. , Cedraz-Mercez Pedro L. , Costa-E-Sousa Ricardo H. , Olivares Emerson L. , Badauê-Passos-Jr Daniel , Medeiros Magda A. , Côrtes Wellington S. , Reis Luís C.
Published: April 2005

We investigate the influence of brain serotonin depletion on the sodium appetite. Rats depleted of serotonin through the systemic administration of p-chlorophenylalanine (300 mg/kg, ip, for 2 days) showed an intense natriorexigenic response induced by sodium depletion (furosemide, 20 mg/kg, sc, 24 h before water and 1.8% NaCl presentation). Intake of 1.8% NaCl was always higher than that observed for the control group (12.9 ± 1.4 and 21.4 ± 3.0 mL vs 5.7 ± 1.2 and 12.7 ± 1.6 mL, 30 and 300 min after water and saline presentation). After 24 h, the natriorexigenic response continued to be significantly higher compared to control (33.6±5.1 vs 21.9±3.6 mL,P <0.05). Fourteen days after p-chlorophenylalanine administration, 1.8% NaCl intake did not differ from controls. Serotonin-depleted rats expressed an early natriorexigenic response after isoproterenol administration on the third day after the first injection of p-chlorophenylalanine. An increase in 1.8% NaCl intake was first observed at 120 min (1.9 ± 0.2 vs 0.45 ± 0.3 mL,P <0.05) and remained high up to the end of the 24-h observation period (17.3±3.2 vs 1.1±0.5 mL,P <0.05). After 7 and 14 days, the natriorexigenic response became comparable to that of control animals. Present results show that brain serotonin depletion exaggerates the sodium appetite induced by the paradigm of sodium depletion or after beta-adrenergic stimulation.
From birdsong to speech: a plea for comparative approaches
Authors: Todt Dietmar
Published: April 2005

Human language and speech are unique accomplishments. Nevertheless, they share a number of characteristics with other systems of communication, and investigators have thus compared them to birdsong and the vocal signaling of nonhuman primates. Particular interesting parallels concern the development of singing and speaking. These behaviors rely on auditory perception, subsequent memorization and finally, the generation of vocal imitations. Several mechanisms help young individuals to deal with the various challenges during the time of signal development. Specific differences aside, astounding parallels can be found also in how a human and a particularly accomplished bird like the Common Nightingale Luscinia megarhynchos treat the experience of many different sound patterns or songs. As a consequence of such exposure, both human infants and young birds eventually acquire large repertoires of verbal or vocal signals. These achievements, however, require access to specific memory mechanisms which are well adapted to the purposes they serve, thereby allowing them to fulfil their species typical roles. With such aspects as a reference, birdsong is an excellent biological model for memory research and also an appropriate system for the study of evolutionary strategies in a very successful class of organisms.