Trade-off between offspring number and offspring size in the marine copepod Euterpina acutifrons at different food concentrations

collected females of the marine copepod Euterpina acutifrons monthly from November 1994 to January 1996 at a station located in Ria de Vigo (Spain). A trade-off between egg size and egg number was found. As food concentration measured as mean fluorescence in the water column diminished, mean number of eggs per sac carried per female decreased, whereas mean egg size increased. An experiment carried out with adult females cultured at different food concentrations confirmed the field results, and also showed that as egg size increased, there, was an increase in naupliar body length at hatching; nauplii developed faster to first copepodite stage, and net reproductive rate was higher. Therefore, the reproductive strategy of directing more energy toward offspring size rather than offspring number, at low food concentrations, clearly increases reproductive success.Postprin

Memory and intelligence: Interdependence according to processes and content of tasks

is study investigates the characteristics of the specific memory factors (processes and content) that are associated to the Gsm from the CHC model. Memory tasks with different content, including various aptitude tests and a general intelligence test, were administered to a sample of university students. Two models that relate the general Gsm aptitude, with working memory and memory span, and with verbal-numerical and visual-spatial aptitudes were tested. Results indicate good fit indices for both models tested, as well as evidence for a positive regression between Gsm and working memory and between Gsm and visuospatial content. In both models we observed standardized regression of 0.54 and of 0.73 between Gsm and factor g. Implications for the understanding of the relation between memory and intelligence are discussed.info:eu-repo/semantics/publishedVersio

Characterization of visuomotor/imaginary movements in EEG: an information theory and complex network approach

Imagined activities could actually be a cognitive basis for creative thinking. However, it is still unknown how they might be related with the architecture of the brain. A recent study has proved the relevance of the imagined activity when investigating neuronal diseases by comparing variations in the neuronal activity of patients with brain diseases and healthy subjects. One important aspect of the scientific methodologies focused on neuronal diseases is therefore to provide a trustablemethodology that could allow us to distinguish between realized and imagined activities in the brain. The electroencephalogram is the result of synchronized action of the cerebrum, and our end is portraying the network dynamics through the neuronal responses when the subjects perform visuomotor and specific imaginary assignments. We use a subtle information theoretical approach accounting for the time causality of the signal and the closeness centrality of the different nodes. More specifically we perform estimations of the probability distribution of the data associated to each node using the Bandt and Pompe approach to account for the causality of the electroencephalographic signals. We calculate the Jensen-Shannon distance across different nodes, and then we quantify how fast the information flow would be through a given node to other nodes computing the closeness centrality.We performa statistical analysis to compare the closeness centrality considering the different rhythmic oscillation bands for each node taking into account imagined and visuomotor tasks. Our discoveries stress the pertinence of the alpha band while performing and distinguishing the specific imaginary or visuomotor assignments.Instituto de Física La Plat

Effect of the radiochemical impurities of 99mTc-MIBI on the diagnostic quality of the images in nuclear medicine

En este trabajo se analiza la confiabilidad del método de control de pureza radioquímica del 99mTc-MIBI utilizado en los servicios de medicina nuclear y se discute la influencia de la mayor existencia de impurezas radioquímicas en la calidad diagnóstica de las imágenes obtenidas.This work analyzes the reliability of the radiochemical purity control method of 99mTc-MIBI used in nuclear medicine services and the influence of the greater presence of radiochemical impurities in the diagnostic quality of the obtained images.Fil: Guisande Donadio, Sabrina Natali. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Física; ArgentinaFil: Sanchez, J.. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Física; ArgentinaFil: Garavaglia, L.. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Física; ArgentinaFil: Rozanskas, S.. Cimed; ArgentinaFil: Dopta, G.. Instituto de Cardiología La Plata; ArgentinaFil: Pertusi, K.. Instituto de Cardiología la Plata; ArgentinaFil: Sanz, V.. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Física; Argentina. Comisión Nacional de Energía Atómica; ArgentinaFil: Mele, A.. Instituto de Cardiología La Plata; ArgentinaFil: Illanes, L.. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Física; ArgentinaFil: Chain, Cecilia Yamil. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentin

Climate variability and Dinophysis acuta blooms in an upwelling system

Dinophysis acuta is a frequent seasonal lipophilic toxin producer in European Atlantic coastal waters associated with thermal stratification. In the Galician Rías, populations of D. acuta with their epicentre located off Aveiro (northern Portugal), typically co-occur with and follow those of Dinophysis acuminata during the upwelling transition (early autumn) as a result of longshore transport. During hotter than average summers, D. acuta blooms also occur in August in the Rías, when they replace D. acuminata. Here we examined a 30-year (1985–2014) time series of D. acuta from samples collected by the same method in the Galician Rías. Our main objective was to identify patterns of distribution and their relation with climate variability, and to explain the exceptional summer blooms of D. acuta in 1989–1990. A dome-shaped relationship was found between summer upwelling intensity and D. acuta blooms; cell maxima were associated with conditions where the balance between upwelling intensity and heating, leading to deepened thermoclines, combined with tidal phase (3 days after neap tides) created windows of opportunity for this species. The application of a generalized additive model based on biological (D. acuta inoculum) and environmental predictors (Cumulative June–August upwelling CUIJJA, average June–August SSTJJA and tidal range) explained more than 70% of the deviance for the exceptional summer blooms of D. acuta, through a combination of moderate (35,000–50,000 m3 s−1 km−1) summer upwelling (CUIJJA), thermal stratification (SSTJJA > 17 °C) and moderate tidal range (∼2.5 m), provided D. acuta cells (inoculum) were present in July. There was no evidence of increasing trends in D. acuta bloom frequency/intensity nor a clear relationship with NAO or other long-term climatic cycles. Instead, the exceptional summer blooms of 1989–1990 appeared linked to extreme hydroclimatic anomalies (high positive anomalies in SST and NAO index), which affected most of the European Atlantic coast.Versión del editor3,083

Two new species of Odontostilbe historically hidden under O. microcephala (Characiformes: Cheirodontinae)

Specimens historically identified as Odontostilbe microcephala from the upper rio Paraná and Andean piedmont tributaries of the río Paraguay are reviewed and split in three species. We found that the distribution of O. microcephala is restricted to the Andean slope of the río Paraguay basin. The species is distinguished from congeners with subterminal mouth by the elongate body, usually 10-12 gill rakers on upper branch and smaller horizontal orbital diameter (24.6-32.8 % HL, mean 28.7%). Specimens from upper rio Paraná constitute two new species, diagnosed from other Cheirodontinae by the presence of mesopterygoid teeth, grouped on median portion and forming a continuous row. The new species are distinguished from each other by having premaxillary teeth with five cusps vs. nine cusps and by the number of lamellae in left and right sides of central median raphe of olfactory rosette with 20-21 vs. 11-12.Espécimes historicamente identificados com Odontostilbe microcephala do rio Paraná e tributários do río Paraguay, foram revisados e separados em três espécies. A distribuição de O. microcephala é restrita ao sopé andino da bacia do río Paraguay. A espécie é distinta das congêneres com boca subterminal pela forma alongada, geralmente 10-12 rastros branquiais no ramo superior e menor diâmetro horizontal da órbita (24,6-32,8 % CC, média 28,7%). Espécimes do alto rio Paraná constituem duas espécies novas diagnosticadas de outros Cheirodontinae pela presença de dentes no mesopterigoide, agrupados em sua porção média e formando uma fileira continua. As novas espécies distinguem-se por ter dentes premaxilares com cinco cúspides vs. nove cúspides e pelo número de lamelas nos lados esquerdo e direito da rafe central da roseta olfativa com 20-21 vs. 11-12

Dietary Essential Amino Acids Affect the Reproduction of the Keystone Herbivore Daphnia pulex

Recent studies have indicated that nitrogen availability can be an important determinant of primary production in freshwater lakes and that herbivore growth can be limited by low dietary nitrogen availability. Furthermore, a lack of specific essential nitrogenous biochemicals (such as essential amino acids) might be another important constraint on the fitness of consumers. This might be of particular importance for cladoceran zooplankton, which can switch between two alternative reproductive strategies – the production of subitaneously developing and resting eggs. Here, we hypothesize that both the somatic growth and the type of reproduction of the aquatic keystone herbivore Daphnia is limited by the availability of specific essential amino acids in the diet. In laboratory experiments, we investigated this hypothesis by feeding a high quality phytoplankton organism (Cryptomonas) and a green alga of moderate nutritional quality (Chlamydomonas) to a clone of Daphnia pulex with and without the addition of essential amino acids. The somatic growth of D. pulex differed between the algae of different nutritional quality, but not dependent on the addition of dissolved amino acids. However, in reproduction experiments, where moderate crowding conditions at saturating food quantities were applied, addition of the essential amino acids arginine and histidine (but not lysine and threonine) increased the total number and the developmental stage of subitaneous eggs. While D. pulex did not produce resting eggs on Cryptomonas, relatively high numbers of resting eggs were released on Chlamydomonas. When arginine and histidine were added to the green algal diet, the production of resting eggs was effectively suppressed. This demonstrates the high, but previously overlooked importance of single essential amino acids for the reproductive strategy of the aquatic keystone herbivore Daphnia

Double trouble at high density::Cross-level test of ressource-related adaptive plasticity and crowding-related fitness.

Population size is often regulated by negative feedback between population density and individual fitness. At high population densities, animals run into double trouble: they might concurrently suffer from overexploitation of resources and also from negative interference among individuals regardless of resource availability, referred to as crowding. Animals are able to adapt to resource shortages by exhibiting a repertoire of life history and physiological plasticities. In addition to resource-related plasticity, crowding might lead to reduced fitness, with consequences for individual life history. We explored how different mechanisms behind resource-related plasticity and crowding-related fitness act independently or together, using the water flea Daphnia magna as a case study. For testing hypotheses related to mechanisms of plasticity and crowding stress across different biological levels, we used an individual-based population model that is based on dynamic energy budget theory. Each of the hypotheses, represented by a sub-model, is based on specific assumptions on how the uptake and allocation of energy are altered under conditions of resource shortage or crowding. For cross-level testing of different hypotheses, we explored how well the sub-models fit individual level data and also how well they predict population dynamics under different conditions of resource availability. Only operating resource-related and crowding-related hypotheses together enabled accurate model predictions of D. magna population dynamics and size structure. Whereas this study showed that various mechanisms might play a role in the negative feedback between population density and individual life history, it also indicated that different density levels might instigate the onset of the different mechanisms. This study provides an example of how the integration of dynamic energy budget theory and individual-based modelling can facilitate the exploration of mechanisms behind the regulation of population size. Such understanding is important for assessment, management and the conservation of populations and thereby biodiversity in ecosystems

Análise do impacto do tênis e coturno fornecidos pelo Exército Brasileiro durante a marcha

O objetivo do presente estudo foi comparar a absorção de impacto durante a marcha descalço e com tênis e coturno fornecidos pelo Exército Brasileiro. A amostra foi composta por 20 soldados saudáveis recém-incorporados sem sintomas ou lesões musculoesqueléticas ou neurológicas que interferissem na marcha. Os sujeitos foram instruídos a caminhar em uma plataforma de madeira de 10 metros de comprimento por um metro de largura, com duas plataformas de força (Bertec, EUA) embutidas no centro. O componente vertical da força de reação do solo foi avaliado durante a marcha nas situações tênis, coturno e descalço. O sistema de cinemetria (Qualysis, Suécia) foi utilizado para medir a velocidade da marcha em cada situação de teste. O primeiro pico de força (PPF), o tempo para atingir o PPF (T_PPF), pico transiente de impacto (IPF) e a taxa de aceitação do peso (TAP) entre 10% e 30%, 30% e 50%, 50% e 70%, 70% e 90% e 10% e 90% do PPF foram avaliadas. O T_PPF foi em média 1s menor (p < 0,0001), o IPF e a TAP entre 10% e 30% do PPF foram maiores (p < 0,0001, ambos) descalço comparados a marcha com tênis e coturno. Não foi observado diferença estatística nas outras variáveis estudadas nas três condições de teste, bem como em nenhuma variável na comparação entre tênis e coturno. Os calçados avaliados são eficientes em reduzir o impacto durante a marcha por atrasar em média 1 s o tempo em que o PPF foi atingido, reduzir o IPF e a TAP nos primeiros 30% do PPF