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AbstractAnthropic activities impact ecosystems worldwide thus contributing to the rapid erosion of biodiversity. The failure of traditional strategies targeting single species highlighted ecosystems as the most suitable scale to plan biodiversity management. Network analysis represents an ideal tool to model interactions in ecosystems and centrality indices have been extensively applied to quantify the structural and functional importance of species in food webs. However, many network studies fail in deciphering the ecological mechanisms that lead some species to occupy the most central positions in food webs. To address this question, we built a high-resolution food web of the Gulf of California and quantified species position using 15 centrality indices and the trophic level. We then modelled the values of each index as a function of traits and other attributes (e.g., habitat). We found that body size and mobility are the best predictors of indices that characterize species importance at local, meso- and global scale, especially in presence of data accounting for energy direction. This result extends previous findings that illustrated how a restricted set of traitaxes can predict whether two species interact in food webs. In particular, we show that traits can also help understanding the way species are affected by and mediate indirect effects. The traits allow focusing on the processes that shape the food web, rather than providing case-specific indications as the taxonomy-based approach. We suggest that future network studies should consider the traits to explicitly identify the causal relationships that link anthropic impacts to role changes of species in food webs.

El dolor inguinal o de cadera es un motivo de consulta muy frecuente. Debido a las múltiples causas que pueden generarlo, y a que en muchas ocasiones comparten características clínicas y demográficas, las pruebas de imagen desempeñan un papel complementario en el diagnóstico etiológico. Se han descrito nuevas formas de atrapamiento extraarticular de la cadera como causa de dolor y limitación funcional, en especial en pacientes jóvenes activos. Incluyen el atrapamiento isquiofemoral, el choque subespinoso o de la espina iliaca anteroinferior, el atrapamiento del iliopsoas y el choque pélvico-trocantéreo. De forma general, se deben a un problema mecánico que conduce al contacto anormal o excesivo entre el fémur proximal y la pelvis ósea, o las partes blandas interpuestas. Realizamos una revisión actualizada de estas formas de atrapamiento extraarticular de la cadera, describiendo la fisiopatología, las manifestaciones clínicas, los hallazgos radiológicos más comunes y el tratamiento.

Cement-based materials are commonly used in the multibarrier systems of radioactive waste repositories. Under the sub-surface environmental conditions they are exposed to during service-life, the chemical composition of the initially highly alkaline cement pore fluid may be altered by the influence of external ions and the leaching of dissolved species present in the cement interstitial solution, both of which processes are mainly ruled by ionic diffusion. Furthermore, the perturbation induced in the local thermodynamic equilibrium of the system yields to a series of dissolution/precipitation reactions which may result in a significant reorganization of the microstructure of concrete, in terms of both the distribution of mineral phases and the physical morphology of the capillary pore network, thus causing the concrete properties to undergo a gradual decline. Therefore, the long-term performance of concrete structures is a relevant issue in relation to the safety assessment of radioactive waste disposals. The analysis of the evolution of concrete degradation is a challenging task. It is also one that stresses the relevance of the development of reliable modeling techniques aimed at the prediction of long-term concrete behavior. The present work deals with the conceptualization of concrete both as a mineral aggregate, thus susceptible to deterioration, and as a porous material, where transport processes are expected to take place. Coupled reactive transport models are required to cope with the highly complex cyclic interactions arising between the chemical reactions which take place in the water-concrete interface and diffusive and advective transport in the aqueous phase. The approach taken herein aims at formulating and testing reactive transport numerical models by reproducing recent experiments reported in the scientific literature. Such procedure is intended to provide insight into the very nature of the phenomena involved, particularly those related to the appropriate methods available to describe ionic diffusion and the accuracy of the constitutive laws (e.g., porosity/permeability, porosity/diffusivity, etc.) developed for cement-based materials.

La otosclerosis es una otodistrofia primaria del hueso temporal que produce una hipoacusia de transmisión progresiva. El diagnóstico es generalmente clínico, pero en ocasiones es necesaria la realización de una tomografía computarizada multidetector (TCMD), que es la técnica de imagen de elección. El objetivo de este artículo es realizar una actualización sistemática de la utilidad de las técnicas de imagen en el diagnóstico y la valoración posquirúrgica de la otosclerosis, fundamentalmente del papel de la TCMD, con el fin de disminuir el riesgo quirúrgico.

Quaternary sediments and soils at the Forsmark site (Sweden) would constitute the last barrier for radionuclide migration interposed between a deep repository of high level nuclear wastes (HLNW) and surface ecological systems. The retention capacity of these sediments is evaluated by means of reactive transport simulations. Two different scenarios have been modelled: (1) Inflow of deep fluids carrying radionuclides into shallow aquifers hosted in the carbonate glacial till, and (2) Inflow of deep fluids carrying radionuclides into organic matter-bearing clays. The model results predict that caesium is very efficiently retained in both scenarios for periods longer than 3000 years due to the strong affinity of this ion with the frayed edgesites of the illite layers. Strontium is also retained via cation exchange in illite and, in a lesser extent, via co-precipitation in calcite. The retention efficiency for strontium, however, quickly decreases to 0 after 1000 years. Uranium is retained in both scenarios with retention efficiencies higher than 40% at long term (>3000 years) due to precipitation of amorphous uraninite and adsorption on Fe(III) oxyhydroxides. Radium is only retained in the till aquifer since co-precipitation with barium sulphate does not occur in the clay porewater.

Cement-based materials are commonly used in the multibarrier systems of radioactive waste repositories. Under the sub-surface environmental conditions they are exposed to during service-life, the chemical composition of the initially highly alkaline cement pore fluid may be altered by the influence of external ions and the leaching of dissolved species present in the cement interstitial solution, both of which processes are mainly ruled by ionic diffusion. Furthermore, the perturbation induced in the local thermodynamic equilibrium of the system yields to a series of dissolution/precipitation reactions which may result in a significant reorganization of the microstructure of concrete, in terms of both the distribution of mineral phases and the physical morphology of the capillary pore network, thus causing the concrete properties to undergo a gradual decline. Therefore, the long-term performance of concrete structures is a relevant issue in relation to the safety assessment of radioactive waste disposals. The analysis of the evolution of concrete degradation is a challenging task. It is also one that stresses the relevance of the development of reliable modeling techniques aimed at the prediction of long-term concrete behavior. The present work deals with the conceptualization of concrete both as a mineral aggregate, thus susceptible to deterioration, and as a porous material, where transport processes are expected to take place. Coupled reactive transport models are required to cope with the highly complex cyclic interactions arising between the chemical reactions which take place in the water-concrete interface and diffusive and advective transport in the aqueous phase. The approach taken herein aims at formulating and testing reactive transport numerical models by reproducing recent experiments reported in the scientific literature. Such procedure is intended to provide insight into the very nature of the phenomena involved, particularly those related to the appropriate methods available to describe ionic diffusion and the accuracy of the constitutive laws (e.g.,?porosity/permeability, porosity/diffusivity, etc.) developed for cement-based materials.

We studied the leaf budget in two forest stream sites: site D was located in a stream that flows through deciduous forest, and site E was located in a stream that flows through a eucalyptus plantation. Leaf inputs, transport, benthic storage and breakdown rates at both sites at different periods were measured over 5 years. Data have been combined to calculate leaf budgets with the assumption that both streams were in steady state. The total leaf input was 20 % lower at site E, but the mean benthic stock of leaves and the amount of leaves that was processed were about 1.5 times higher than at site D. Inputs of nitrogen and phosphorus associated with leaves were 50 and 20 % lower at site E, but small differences in the benthic storage of nutrients were observed between the two sites. The streams processed 31-57 % of the nitrogen, and 20-57 % of the phosphorus contained in the leaf input. Afforestation with eucalyptus has a low impact on leaf litter processing as the longer residence time of eucalyptus leaves in the stream balances their lower processing rate. However, it modifies nutrient fluxes associated with leaf litter due to the low nutrient content of eucalyptus leaves and to their role as nutrient sources during leaf decay. At both streams, alder litter was processed more efficiently than other species and was the main source of nitrogen and phosphorus for stream decomposers. We hypothesize that dependence on this fast decaying species is an indication of the disturbance of CPOM dynamics due to historical changes in our streams and that it may be difficult to isolate the effects of former forest disturbances from the impact of eucalyptus plantations.

Abstract: In order to obtain protein-based amphoteric surfactants with antimicrobial properties, N α -lauroyl arginine dipeptides have been prepared by condensation between N α -lauroyl arginine and amino acids which come from a collagen hydrolysate. Some surfactant properties and the minimum inhibitory concentration against Gram positive and Gram negative bacteria have been evaluated. All types of compounds presented a surfactant-like behavior. Furthermore, the compounds described in this paper may be considered as mild preservative or protective substances.

To test whether afforestation with eucalyptus affects the amount, quality, and timing of litter inputs, we evaluated the inputs of coarse particulate organic matter (CPOM) to 2 headwater streams, one flowing through a mixed deciduous forest and one through a plantation of Eucalyptus globulus. Vertical and lateral traps were sampled at least monthly, and the material collected was sorted into 4 main categories: fallen leaves (several species), fruits and flowers, twigs and bark, and debris. The eucalyptus plantation resulted in a reduction of 32% of total litter inputs, and 73% of lateral inputs, compared to the mixed deciduous forest. It also had a less marked seasonal pattern of inputs, and different timing of peak litterfall, the peak in the deciduous forest occurring in autumn, whereas in the eucalyptus plantation the peak occurred in summer. Similarly, leaf diversity was greatly reduced under the eucalyptus, with 98% of the leaf litter mass from 1 species, resulting in broad changes in litter quality. Litter inputs in the eucalyptus plantations contributed 67% less nitrogen and 65% less phosphorus to the stream than in the deciduous forest. Although eucalyptus plantations result in broad changes in organic inputs, no drastic impacts on the structure or function of benthic communities are evident so far in the Agüera stream. Nevertheless, caution suggests maintaining the quantity and timing of allochthonous inputs by keeping buffer strips of native riparian forest.