599 research outputs found
The 50th anniversary of the Declaration on Friendly Relations and its Role in the Jurisprudence of the International Court of Justice
In commemoration of the fifty-year anniversary of the adoption of the United Nations General Assembly resolution 2625 (XXV), Declaration on Principles of International Law concerning Friendly Relations and Co-operation among States in accordance with the Charter of the United Nations, it is fitting to assess the current relevance of this document in the international legal order. An indepth study of the contentious cases and the advisory opinions of the International Court of Justice allows to demonstrate that this instrument is not a mere declaration. On the contrary, it will be shown that, in the present day, it is a key instrument in the resolution of disputes between States.En conmemoración de los cincuenta años de la adopción de la resolución 2625 (XXV) de la Asamblea General de las Naciones Unidas, Declaración sobre los principios de derecho internacional referentes a las relaciones de amistad y a la cooperación entre los Estados de conformidad con la Carta de las Naciones Unidas, es pertinente valorar la relevancia actual de este documento en el ordenamiento jurídico internacional. Un detallado estudio de los casos contenciosos y las opiniones consultivas de la Corte Internacional de Justicia permite demostrar que este instrumento no es una mera declaración. Muy por el contrario, se demostrará que, hoy en día, es un instrumento clave en la resolución de disputas entre los Estados
Oferta de implantes de prótesis total de cadera en Cataluña
El crecimiento exponencial de la oferta de implantes de prótesis total de cadera
hace difícil para el cirujano ortopédico establecer criterios de elección, por este motivo hemos realizado
un análisis de la oferta actual de los mismos. Se han identificado 67 modelos de implantes
de prótesis total de cadera primaria y 19 modelos de revisión comercializados en la comunidad
catalana por 24 empresas. El número de variables, de material o diseño de los distintos modelos,
sin tener en cuenta las diversas medidas de vástagos, cuellos y cótilos, ha sido de 55. Hemos encontrado
referencias bibliográficas de resultados clínicos de un 25% de las prótesis. El rango de
coste de los implantes ha sido de 70.000 a 300.570 pesetas para las prótesis cementadas, con un
precio medio de 172.805 pesetas; de 375.654 a 648.606 pesetas para las no cementadas, con un
precio medio de 480.301 pesetas, y de 412.552 a 713.000 pesetas de las prótesis de revisión, con
una media de 568.138 pesetas. Esta dispersión de modelos y precios es mayor que la de otros países
de nuestro entorno, y el porcentaje de publicaciones de resultados clínicos encontrado es algo
menor que el reportado por algunos autores. Frente a esta situación creemos que serían necesarios
estudios clínicos a largo término y sistemas de evaluación estandarizados para poder decidir
con criterios rigurosos si los nuevos implantes que aparecen en el mercado con costes más elevados
tienen ventajas suficientes para cambiar indicaciones de implantes largamente probados.The exponential growth of the different models of THA actually in offer makes
difficult to the orthopaedic surgeon to find sound criteria for the selection of the proper implant.
This paper is an attempt to analyse the models actually in offer. We have identified 67 primary
THAs types and 19 revision models, commercialised by 24 companies at the catalonian community.
The number of variables, materials or designs between different patterns, independently of the size
of femoral and acetabular components, has been of 55. Only 25% of implants are supported by
reports in the orthopaedic literature. The cost range of implants varied from 70,000 to 300,570 pts.
for cemented prosthesis (average: 172,895); from 375,654 to 648,606 pts. for cementless models
(average: 480,391); the cost range for revision models varied from 412,552 to 713,000 pts., with an
average of 568,138 pts. Such a variety of designs and prices is greater than in other countries
of our environment, and the percentage of reports about clinical results that we have found is
smaller than the noticed by some authors. We believe that it would be necessary some long term
prospective studies and standarized evaluation systems in order to decide if the newer implants,
with more expensive price, have enough advantages to substitute the classic implants widely used
Metallic magnetic nanoparticles
In this paper, we reviewed some relevant aspects of the magnetic properties of metallic nanoparticles with small size ( below 4 nm), covering the size effects in nanoparticles of magnetic materials, as well as the appearance of magnetism at the nanoscale in materials that are nonferromagnetic in bulk. These results are distributed along the text that has been organized around three important items: fundamental magnetic properties, different fabrication procedures, and characterization techniques. A general introduction and some experimental results recently obtained in Pd and Au nanoparticles have also been included. Finally, the more promising applications of magnetic nanoparticles in biomedicine are indicated. Special care was taken to complete the literature available on the subject
Two dimensional electron gas confined over a spherical surface: Magnetic moment
Magnetism of capped nanoparticles, NPs, of non- magnetic substances as Au and ZnO is briefly reviewed. The source of the magnetization is discussed on the light of recent X-ray magnetic circular dichroism experiments. As magnetic dichroism analysis has pointed out impurity atoms bonded to the surface act as donor or acceptor of electrons that occupy the surface states. It is proposed that mesoscopic collective orbital magnetic moments induced at the surface states can account for the experimental magnetism characteristic of these nanoparticles. The total magnetic moment of the surface originated at the unfilled Fermi level can reach values as large as 10(2) or 10(3) Bohr magnetons
The performance of biological indicators in assessing the ecological state of streams with varying catchment urbanisation levels in Coimbra, Portugal
The growth of human populations has resulted in the expansion of metropolitan areas and changes in land use, both of which affect watersheds and streams. The ecological integrity of streams is likely to be negatively affected by urbanisation, compromising freshwater ecosystem services. The aim of this study was to assess how efficient structural and functional indicators are in evaluating the ecological conditions of water in urban stream ecosystems. Two urban streams crossing the city and one stream crossing a suburban area of Coimbra, Portugal were selected. Total impervious area (TIA) was used as an indicator of urbanisation. Physical and chemical parameters of water were measured and analysed within the Water Framework Directive (WFD/2000/60/EC). Benthic macroinvertebrates were used as structural indicators, and the IBMWP biotic index (modified) and the Portuguese IPtIS index were calculated. The decomposition rates of oak (Quercus robur) and alder (Alnus glutinosa) leaves were used as indicators of functional quality. Biotic indices and litter decomposition rates indicated poor ecological conditions in the urban streams compared to the suburban stream, consistent with the degree of urbanisation. The decrease in ecological quality in urban streams most likely reflected decreases in dissolved oxygen and increases in water temperature and conductivity. We emphasise (a) the need to combine physical and chemical data with biological data and (b) the high performance of a novel functional indicator based on litter breakdown rate as an accurate, efficient and integrative measure of ecological integrity in urban streams.El crecimiento de la población humana en las últimas décadas ha provocado el aumento de las áreas urbanas y cambios en los usos del suelo que afectan a las cuencas hidrográficas y a sus ríos. Es probable que la integridad ecológica de los ríos urbanos se vea afectada negativamente, comprometiendo los servicios ecosistémicos proporcionados por las aguas dulces. El objetivo de este estudio fue comparar el rendimiento entre diferentes metodologías en la evaluación química y ecológica del agua en ríos urbanos. Se han seleccionado dos ríos urbanos que cruzan la ciudad de Coimbra, Portugal, y un río que cruza un área suburbana. Como indicador de urbanización se us'o el área total impermeable (TIA). Se han utilizado parámetros físico-químicos que se han analizado siguiendo la Directiva Marco del Agua (2000/60/EC). Como indicadores estructurales se han utilizado los macroinvertebrados bentónicos, calculándose el índice biológico IBMWP (modificado) y el índice IPtIS portugués. Como indicadores funcionales de la calidad ecológica se han usado las tasas de descomposición de hojarasca de roble (Quercus robur L.) y aliso (Alnus glutinosa (L.) Gaertner). Los parámetros físicos y químicos de todos los ríos indicaron "buena calidad" según los parámetros de calidad nacionales y la Directiva Marco del Agua. Sin embargo, los indicadores biológicos y las tasas de descomposición de hojarasca indicaron malas condiciones ecol'ogicas en los ríos urbanos comparados con el río en el área suburbana coincidiendo también con el grado de urbanización. Esto sugiere que los indicadores biológicos (estructurales y funcionales) proporcionan información más temprana, precisa e integrada del sistema que las medidas de la química del agua que no reflejan el valor ecológico de las aguas, su calidad o los impactos ecológicos potenciales. En el estudio se hace especial énfasis en (a) la necesidad de combinar datos físico-químicos con medidas biológicas y (b) la elevada eficiencia de la descomposición como indicador preciso de la integridad ecológica y calidad ambiental en un número creciente de ríos urbanos
Spinodal decomposition of Fe-Cu nanocrystals: Control of atomic-magnetic-moment and magnetic properties
Experimental results corresponding to the saturation magnetization and coercive field during the decomposition, upon annealing, of bcc and fcc Fe_xCu_(1-x), obtained by mechanical alloying are reported. The overall behavior points out that the decomposition takes place in two steps: (i) at low temperatures a decrease of the saturation magnetic moment as well as an anomalous thermal dependence of coercive field are observed, however, no phase transformation is detected, and (ii) for further annealing temperatures a new phase appears; the magnetization tends to increase and the coercive field abruptly increases. The analysis of the results leads us to conclude that the first step corresponds to a spinodal decomposition. Fluctuations in the local composition give rise to coexistence of adjacent regions with Curie temperature varying continuously in a range of 1000 K across distances of a few nanometers, thus allowing the tailoring of the magnetic nanostructures
De novo methylation causes a tissue-specific polymorphic EcoRI pattern at the human epidermal growth factor receptor gene
Mechanically driven alloying of immiscible elements (Comment)
In conclusion we have proven that the fact that both fcc FeCu and bcc Fe magnetization agree at 300 K is simply an accident and our data at low temperature show clearly that the Fe contribution after precipitation from the metastable phase has a deficiency in magnetization of at least 20% with respect to the Fe state in fcc FeCu metastable solid solution
Glutamatergic neurotransmission in aging: a critical perspective.
Abstract The effects of aging on glutamate neurotransmission in the brain is reviewed and evaluated. Glutamate is the neurotransmitter in most of the excitatory synapses and appears to be involved in functions such as motor behaviour, cognition and emotion, which alter with age. However, relatively few studies have been conducted to study the relationship between glutamate and aging of the brain. The studies presented here indicate the existence of a number of changes in the glutamatergic system during the normal process of aging. First, an age-related decrease of glutamate content in tissue from cerebral cortex and hippocampus has been reported, although it may be mainly a consequence of changes in metabolic activity rather than glutamatergic neurotransmission. On the other hand, studies in vitro and in vivo have shown no changes in glutamate release during aging. Since glutamate sampled in most of these studies is the result of a balance between release and uptake processes, the lack of changes in glutamate release may be due to compensatory changes in glutamate uptake. In fact, a reduced glutamate uptake capacity, as well as a loss in the number of high affinity glutamate transporters in glutamatergic terminals of aged rats, have been described. However, the most significant and consistent finding is the decrease in the density of glutamatergic NMDA receptors with age. A new perspective, in which glutamate interacts with other neurotransmitters to conform the substrates of specific circuits of the brain and its relevance to aging, is included in this review. In particular, studies from our laboratory suggest the existence of age-related changes in the interaction between glutamate and other neurotransmitters, e.g. dopamine and GABA, which are regionally specific
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