Open Access Influence on Argentinean Scientific Community's Publishing Patterns

Este estudio tiene como objetivo estimar la influencia del acceso abierto en los patrones de publicación de la comunidad científica argentina en diferentes campos temáticos (Medicina; Física y Astronomía; Agricultura y Ciencias biológicas y Ciencias sociales y Humanidades), a partir del análisis del modelo de acceso de las revistas elegidas para comunicar los resultados de investigación en el período 2008-2010. La producción fue recogida de la base de datos SCOPUS y los modelos de acceso de las revistas determinados a partir de la consulta a las fuentes DOAJ, e-revist@s, SCielo, Redalyc, PubMed, Romeo-Sherpa y Dulcinea. Se analizó la accesibilidad real y potencial de la producción científica nacional por las vías dorada y verde, respectivamente, así como también por suscripción a través de la Biblioteca Electrónica de Ciencia y Tecnología del Ministerio de Ciencia, Tecnología e Innovación Productiva de la Nación Argentina. Los resultados muestran que en promedio, y para el conjunto de las temáticas estudiadas, el 70 de la producción científica argentina visible en SCOPUS se publica en revistas que adhieren de una u otra forma al movimiento de acceso abierto, en una relación del 27 para la vía dorada y del 43 para las que permiten el autoarchivo por la vía verde. Entre el 16 y el 30 (según las áreas temáticas) de los artículos publicados en revistas que permiten el autoarchivo se accede vía suscripción. El porcentaje de revistas sin acceso es del orden del 30 en Ciencias Sociales y Humanidades, y alcanza cerca del 45 en el resto de las áreas. Se concluye que Argentina presenta condiciones muy favorables para liberar un alto porcentaje de la literatura científica generada en el país bajo la modalidad del acceso abierto a través de repositorios institucionales y de mandatos para el auto-archivo, contribuyendo además a incrementar la accesibilidad y la preservación a largo plazo de la producción científica y tecnológica nacional

Open Access Influence on Argentinean Scientific Community's Publishing Patterns

Este estudio tiene como objetivo estimar la influencia del acceso abierto en los patrones de publicación de la comunidad científica argentina en diferentes campos temáticos (Medicina; Física y Astronomía; Agricultura y Ciencias biológicas y Ciencias sociales y Humanidades), a partir del análisis del modelo de acceso de las revistas elegidas para comunicar los resultados de investigación en el período 2008-2010. La producción fue recogida de la base de datos SCOPUS y los modelos de acceso de las revistas determinados a partir de la consulta a las fuentes DOAJ, e-revist@s, SCielo, Redalyc, PubMed, Romeo-Sherpa y Dulcinea. Se analizó la accesibilidad real y potencial de la producción científica nacional por las vías dorada y verde, respectivamente, así como también por suscripción a través de la Biblioteca Electrónica de Ciencia y Tecnología del Ministerio de Ciencia, Tecnología e Innovación Productiva de la Nación Argentina. Los resultados muestran que en promedio, y para el conjunto de las temáticas estudiadas, el 70 de la producción científica argentina visible en SCOPUS se publica en revistas que adhieren de una u otra forma al movimiento de acceso abierto, en una relación del 27 para la vía dorada y del 43 para las que permiten el autoarchivo por la vía verde. Entre el 16 y el 30 (según las áreas temáticas) de los artículos publicados en revistas que permiten el autoarchivo se accede vía suscripción. El porcentaje de revistas sin acceso es del orden del 30 en Ciencias Sociales y Humanidades, y alcanza cerca del 45 en el resto de las áreas. Se concluye que Argentina presenta condiciones muy favorables para liberar un alto porcentaje de la literatura científica generada en el país bajo la modalidad del acceso abierto a través de repositorios institucionales y de mandatos para el auto-archivo, contribuyendo además a incrementar la accesibilidad y la preservación a largo plazo de la producción científica y tecnológica nacional

Changes in spatial point patterns of pioneer woody plants across a large tropical landslide

We assessed whether the relative importance of positive and negative interactions in early successional communities varied across a large landslide on Casita Volcano (Nicaragua). We tested several hypotheses concerning the signatures of these processes in the spatial patterns of woody pioneer plants, as well as those of mortality and recruitment events, in several zones of the landslide differing in substrate stability and fertility, over a period of two years (2001 and 2002). We identified all woody individuals with a diameter >1 cm and mapped them in 28 plots measuring 10 × 10-m. On these maps, we performed a spatial point pattern analysis using univariate and bivariate pair-correlation functions; g (r) and g12 (r), and pairwise differences of univariate and bivariate functions. Spatial signatures of positive and negative interactions among woody plants were more prevalent in the most and least stressful zones of the landslide, respectively. Natural and human-induced disturbances such as the occurrence of fire, removal of newly colonizing plants through erosion and clearcutting of pioneer trees were also identified as potentially important pattern-creating processes. These results are in agreement with the stress-gradient hypothesis, which states that the relative importance of facilitation and competition varies inversely across gradients of abiotic stress. Our findings also indicate that the assembly of early successional plant communities in large heterogeneous landslides might be driven by a much larger array of processes than previously thought.

Three-dimensional scroll waves of cAMP could direct cell movement and gene expression in Dictyostelium slugs.

Complex three-dimensional waves of excitation can explain the observed cell movement pattern in Dictyostelium slugs. Here we show that these three-dimensional waves can be produced by a realistic model for the cAMP relay system [Martiel, J. L. & Goldbeter, A. (1987) Biophys J. 52, 807-828]. The conversion of scroll waves in the prestalk zone of the slug into planar wave fronts in the prespore zone can result from a smaller fraction of relaying cells in the prespore zone. Further, we show that the cAMP concentrations to which cells in a slug are exposed over time display a simple pattern, despite the complex spatial geometry of the waves. This cAMP distribution agrees well with observed patterns of cAMP-regulated cell type-specific gene expression. The core of the spiral, which is a region of low cAMP concentration, might direct expression of stalk-specific genes during culmination.

Open Access Influence on Argentinean Scientific Community's Publishing Patterns

Este estudio tiene como objetivo estimar la influencia del acceso abierto en los patrones de publicación de la comunidad científica argentina en diferentes campos temáticos (Medicina; Física y Astronomía; Agricultura y Ciencias biológicas y Ciencias sociales y Humanidades), a partir del análisis del modelo de acceso de las revistas elegidas para comunicar los resultados de investigación en el período 2008-2010. La producción fue recogida de la base de datos SCOPUS y los modelos de acceso de las revistas determinados a partir de la consulta a las fuentes DOAJ, e-revist@s, SCielo, Redalyc, PubMed, Romeo-Sherpa y Dulcinea. Se analizó la accesibilidad real y potencial de la producción científica nacional por las vías dorada y verde, respectivamente, así como también por suscripción a través de la Biblioteca Electrónica de Ciencia y Tecnología del Ministerio de Ciencia, Tecnología e Innovación Productiva de la Nación Argentina. Los resultados muestran que en promedio, y para el conjunto de las temáticas estudiadas, el 70 de la producción científica argentina visible en SCOPUS se publica en revistas que adhieren de una u otra forma al movimiento de acceso abierto, en una relación del 27 para la vía dorada y del 43 para las que permiten el autoarchivo por la vía verde. Entre el 16 y el 30 (según las áreas temáticas) de los artículos publicados en revistas que permiten el autoarchivo se accede vía suscripción. El porcentaje de revistas sin acceso es del orden del 30 en Ciencias Sociales y Humanidades, y alcanza cerca del 45 en el resto de las áreas. Se concluye que Argentina presenta condiciones muy favorables para liberar un alto porcentaje de la literatura científica generada en el país bajo la modalidad del acceso abierto a través de repositorios institucionales y de mandatos para el auto-archivo, contribuyendo además a incrementar la accesibilidad y la preservación a largo plazo de la producción científica y tecnológica nacional

Flow patterns in granulating systems

Particle flow patterns were investigated for wet granulation and dry powder mixing in ploughshare mixers using Positron Emission Particle Tracking (PEPT). In a 4-1 mixer, calcium carbonate with mean size 45 mum was granulated using a 50 wt.% solution of glycerol and water as binding fluid, and particle movement was followed using a 600-mum calcium hydroxy-phosphate tracer particle. In a 20-1 mixer, dry powder flow was studied using a 600-mum resin bead tracer particle to simulate the bulk polypropylene powder with mean size 600 mum. Important differences were seen between particle flow patterns for wet and dry systems. Particle speed relative to blade speed was lower in the wet system than in the dry system, with the ratios of average particle speed to blade tip speed for all experiments in the range 0.01-015. In the axial plane, the same particle motion was observed around each blade; this provides a significant advance for modelling flow in ploughshare mixers. For the future, a detailed understanding of the local velocity, acceleration and density variations around a plough blade will reveal the effects of flow patterns in granulating systems on the resultant distribution of granular product attributes such as size, density and strength. (C) 2002 Elsevier Science B.V All rights reserved.

Pain differs from non-painful attention-demanding or stressful tasks in its effect on postural control patterns of trunk muscles

Pain changes postural activation of the trunk muscles. The cause of these changes is not known but one possibility relates to the information processing requirements and the stressful nature of pain. This study investigated this possibility by evaluating electromyographic activity (EMG) of the deep and superficial trunk muscles associated with voluntary rapid arm movement. Data were collected from control trials, trials during low back pain (LBP) elicited by injection of hypertonic saline into the back muscles, trials during a non-painful attention-demanding task, and during the same task that was also stressful. Pain did not change the reaction time (RT) of the movement, had variable effects on RT of the superficial trunk muscles, but consistently increased RT of the deepest abdominal muscle. The effect of the attention-demanding task was opposite: increased RT of the movement and the superficial trunk muscles but no effect on RT of the deep trunk muscles. Thus, activation of the deep trunk muscles occurred earlier relative to the movement. When the attention-demanding task was made stressful, the RT of the movement and superficial trunk muscles was unchanged but the RT of the deep trunk muscles was increased. Thus, the temporal relationship between deep trunk muscle activation and arm movement was restored. This means that although postural activation of the deep trunk muscles is not affected when central nervous system resources are limited, it is delayed when the individual is also under stress. However, a non-painful attention-demanding task does not replicate the effect of pain on postural control of the trunk muscles even when the task is stressful.

Historical and contemporary mating patterns in remnant populations of the forest tree Fraxinus excelsior L.

Genetic variation at microsatellite markers was used to quantify genetic structure and mating behavior in a severely fragmented population of the wind-pollinated, wind-dispersed temperate tree Fraxinus excelsior in a deforested catchment in Scotland. Remnants maintain high levels of genetic diversity, comparable with those reported for continuous populations in southeastern Europe, and show low interpopulation differentiation (Theta = 0.080), indicating that historical gene exchange has not been limited (Nm = 3.48). We estimated from seeds collected from all trees producing fruits in three of five remnants that F. excelsior is predominantly outcrossing (t(m). = 0.971 +/- 0.028). Use of a neighborhood model approach to describe the relative contribution of local and long-distance pollen dispersal indicates that pollen gene flow into each of the three remnants is extensive (46-95%) and pollen dispersal has two components. The first is very localized and restricted to tens of meters around the mother trees. The second is a long-distance component with dispersal occurring over several kilometers. Effective dispersal distances, accounting for the distance and directionality to mother trees of sampled pollen donors, average 328 m and are greater than values reported for a continuous population. These results suggest that the opening of the landscape facilitates airborne pollen movement and may alleviate the expected detrimental genetic effects of fragmentation.

Spatial patterns of asynuclein positive glial cytoplasmic inclusions in multiple system atrophy

In cases of multiple system atrophy (MSA), glial cytoplasmic inclusions (GCI) were distributed randomly or present in large diffuse clusters (>1,600 μm in diameter) in most areas studied. These spatial patterns contrast with those reported for filamentous neuronal inclusions in the tauopathies and α-synucleinopathies. © 2003 Movement Disorder Society.

A smart sensing platform for the discrimination of human movement

This thesis documents the design, implementation and testing of a smart sensing platform that is able to discriminate between differences or small changes in a persons walking. The distributive tactile sensing method is used to monitor the deflection of the platform surface using just a small number of sensors and, through the use of neural networks, infer the characteristics of the object in contact with the surface. The thesis first describes the development of a mathematical model which uses a novel method to track the position of a moving load as it passes over the smart sensing surface. Experimental methods are then described for using the platform to track the position of swinging pendulum in three dimensions. It is demonstrated that the method can be extended to that of real-time measurement of balance and sway of a person during quiet standing. Current classification methods are then investigated for use in the classification of different gait patterns, in particular to identify individuals by their unique gait pattern. Based on these observations, a novel algorithm is developed that is able to discriminate between abnormal and affected gait. This algorithm, using the distributive tactile sensing method, was found to have greater accuracy than other methods investigated and was designed to be able to cope with any type of gait variation. The system developed in this thesis has applications in the area of medical diagnostics, either as an initial screening tool for detecting walking disorders or to be able to automatically detect changes in gait over time. The system could also be used as a discrete biometric identification method, for example identifying office workers as they pass over the surface.

Seed dispersal and reproduction patterns among Everglades plants

In this study three aspects of sexual reproduction in Everglades plants were examined to more clearly understand seed dispersal and the allocation of resources to sexual reproduction—spatial dispersal process, temporal dispersal of seeds (seedbank), and germination patterns in the dominant species, sawgrass (Cladium jamaicense). Community assembly rules for fruit dispersal were deduced by analysis of functional traits associated with this process. Seedbank ecology was investigated by monitoring emergence of germinants from sawgrass soil samples held under varying water depths to determine the fate of dispersed seeds. Fine-scale study of sawgrass fruits yielded information on contributions to variation in sexually produced propagules in this species, which primarily reproduces vegetatively. It was hypothesized that Everglades plants possess a set of functional traits that enhance diaspore dispersal. To test this, 14 traits were evaluated among 51 species by factor analysis. The factorial plot of this analysis generated groups of related traits, with four suites of traits forming dispersal syndromes. Hydrochory traits were categorized by buoyancy and appendages enhancing buoyancy. Anemochory traits were categorized by diaspore size and appendages enhancing air movement. Epizoochory traits were categorized by diaspore size, buoyancy, and appendages allowing for attachment. Endozoochory traits were categorized by diaspore size, buoyancy, and appendages aiding diaspore presentation. These patterns/trends of functional trait organization also represent dispersal community assembly rules. Seeds dispersed by hydrochory were hypothesized to be caught most often in the edge of the north side of sawgrass patches. Patterns of germination and dispersal mode of all hydrochorous macrophytes with propagules in the seedbank were elucidated by germination analysis from 90 soil samples collected from 10 sawgrass patches. Mean site seed density was 486 seeds/m2 from 13 species. Most seeds collected at the north side of patches and significantly in the outer one meter of the patch edge (p = 0.013). Sawgrass seed germination was hypothesized to vary by site, among individual plants, and within different locations of a plant’s infructescence. An analysis of sawgrass fruits with nested ANOVAs found that collection site and interaction of site x individual plant significantly affect germination ability, seed viability, and fruit size (p ≤ 0.050). Fruit location within a plant’s infructescence did not significantly affect germination. As for allocation of resources to sexual reproduction, only 17.9% of sawgrass seeds germinated and only 4.8% of ungerminated seeds with fleshy endosperm were presumed viable, but dormant. Collectively, only 22% of all sawgrass seeds produced were viable.

Spatial patterns of fish communities along two estuarine gradients in southern Florida

In tropical and subtropical estuaries, gradients of primary productivity and salinity are generally invoked to explain patterns in community structure and standing crops of fishes. We documented spatial and temporal patterns in fish community structure and standing crops along salinity and nutrient gradients in two subtropical drainages of Everglades National Park, USA. The Shark River drains into the Gulf of Mexico and experiences diurnal tides carrying relatively nutrient enriched waters, while Taylor River is more hydrologically isolated by the oligohaline Florida Bay and experiences no discernable lunar tides. We hypothesized that the more nutrient enriched system would support higher standing crops of fishes in its mangrove zone. We collected 50 species of fish from January 2000 to April 2004 at six sampling sites spanning fresh to brackish salinities in both the Shark and Taylor River drainages. Contrary to expectations, we observed lower standing crops and density of fishes in the more nutrient rich tidal mangrove forest of the Shark River than in the less nutrient rich mangrove habitats bordering the Taylor River. Tidal mangrove habitats in the Shark River were dominated by salt-tolerant fish and displayed lower species richness than mangrove communities in the Taylor River, which included more freshwater taxa and yielded relatively higher richness. These differences were maintained even after controlling for salinity at the time of sampling. Small-scale topographic relief differs between these two systems, possibly created by tidal action in the Shark River. We propose that this difference in topography limits movement of fishes from upstream marshes into the fringing mangrove forest in the Shark River system, but not the Taylor River system. Understanding the influence of habitat structure, including connectivity, on aquatic communities is important to anticipate effects of construction and operational alternatives associated with restoration of the Everglades ecosystem.

Does variation in movement tactics and trophic interactions among American alligators create habitat linkages?

1. Highly mobile top predators are hypothesized to spatially and/or temporally link disparate habitats through the combination of their movement and feeding patterns, but recent studies suggest that individual specialization in habitat use and feeding could keep habitats compartmentalized. 2.  We used passive acoustic telemetry and stable isotope analysis to investigate whether specialization in movement and feeding patterns of American alligators (Alligator mississippiensis) in an oligotrophic subtropical estuary created habitat linkages between marine and estuarine/freshwater food webs. 3.  Individual alligators adopted one of the three relatively distinct movement tactics that were linked to variation in diets. Fifty-six per cent of alligators regularly travelled from the upstream (freshwater/mid-estuary) areas into the downstream (marine-influenced) areas where salinities exceed those typically tolerated by alligators. Thirty-one per cent of the alligators made regular trips from the mid-estuarine habitat into the upstream habitat; 13% remained in the mid-estuary zone year-round. 4.  Stable isotopic analysis indicated that, unlike individuals remaining in the mid-estuary and upstream zones, alligators that used the downstream zone fed at least partially from marine food webs and likely moved to access higher prey abundance at the expense of salt stress. Therefore, ‘commuting’ alligators may link marine food webs with those of the estuary and marshes in the coastal Everglades and create an upstream vector for allochthonous nutrient inputs into the estuary. 5.  This study lends further support to the hypothesis that large-bodied highly mobile predators faced with trade-offs are likely to exhibit individual specialization leading to habitat linkages, rather than compartmentalization. However, the conditions under which this scenario occurs require further investigation.

Seed Dispersal and Reproduction Patterns Among Everglades Plants

In this study three aspects of sexual reproduction in Everglades plants were examined to more clearly understand seed dispersal and the allocation of resources to sexual reproduction— spatial dispersal process, temporal dispersal of seeds (seedbank), and germination patterns in the dominant species, sawgrass (Cladium jamaicense). Community assembly rules for fruit dispersal were deduced by analysis of functional traits associated with this process. Seedbank ecology was investigated by monitoring emergence of germinants from sawgrass soil samples held under varying water depths to determine the fate of dispersed seeds. Fine-scale study of sawgrass fruits yielded information on contributions to variation in sexually produced propagules in this species, which primarily reproduces vegetatively. It was hypothesized that Everglades plants possess a set of functional traits that enhance diaspore dispersal. To test this, 14 traits were evaluated among 51 species by factor analysis. The factorial plot of this analysis generated groups of related traits, with four suites of traits forming dispersal syndromes. Hydrochory traits were categorized by buoyancy and appendages enhancing buoyancy. Anemochory traits were categorized by diaspore size and appendages enhancing air movement. Epizoochory traits were categorized by diaspore size, buoyancy, and appendages allowing for attachment. Endozoochory traits were categorized by diaspore size, buoyancy, and appendages aiding diaspore presentation. These patterns/trends of functional trait organization also represent dispersal community assembly rules. Seeds dispersed by hydrochory were hypothesized to be caught most often in the edge of the north side of sawgrass patches. Patterns of germination and dispersal mode of all hydrochorous macrophytes with propagules in the seedbank were elucidated by germination analysis from 90 soil samples collected from 10 sawgrass patches. Mean site seed density was 486 seeds/m2 from 13 species. Most seeds collected at the north side of patches and significantly in the outer one meter of the patch edge (p = 0.013). Sawgrass seed germination was hypothesized to vary by site, among individual plants, and within different locations of a plant’s infructescence. An analysis of sawgrass fruits with nested ANOVAs found that collection site and interaction of site x individual plant significantly affect germination ability, seed viability, and fruit size (p < 0.050). Fruit location within a plant’s infructescence did not significantly affect germination. As for allocation of resources to sexual reproduction, only 17.9% of sawgrass seeds germinated and only 4.8% of ungerminated seeds with fleshy endosperm were presumed viable, but dormant. Collectively, only 22% of all sawgrass seeds produced were viable.