390 research outputs found
Revolución e intervención en Libia. Una interpretación desde la teoría de la guerra justa
Este artículo busca hacer una reflexión sobre
la reciente rebelión y consecuente intervención en Libia en
conexión con la denominada “teoría de la guerra justa”*. En
concreto, trata de proponer un análisis de la relación entre la
JWT y el derecho de rebelión, y la legitimidad de la intervención
humanitaria, poniendo al mismo tiempo de relieve la
complejidad de la JWT y la dificultad de aplicarla en al práctica
The prolific polytypism of silicon carbide
A worked example of polytypism is presented, aimed at assisting undergraduates in the learning and instructors in the teaching of this topic. In particular, this crystallography concept, not necessarily obvious for beginners, is illustrated pedagogically using to that end the model case of the prolific polytypism of silicon carbide (SiC). On the basis of concepts that are easily assimilated by students (i.e. simple topological constraints) this article first presents a unified description of the polytypism phenomenon in SiC that allows one to understand without difficulty the existence of its numerous polytypic variants and how they develop. Then the various notations used to designate these different polytypes are described, and finally the crystal structures of the most common are discussed. This worked example is thus expected to contribute to motivating undergraduates in the study of a crystallography topic that often is not treated in sufficient depth in class.Ministerio de Ciencia y Tecnología MAT2010-1684
Obtención de una sonda específica para evaluar la transcripción del gen STAT5b
The strategy for cloning a 306 bp rat STAT5b fragment, amplified by RT-PCR, into an expression vector is described.The main difference between STAT5a and STAT5b lies within the 3' region of their respective cDNAs, therefore a fragment in this region was amplified. Cloning was achieved by using the new system TOPO-TA recommended, for products difficult to be cloned.The fragment was subcloned into pBlueScript Il SK vector and characterized by sequencing and restriction analysis. Subcloning was done in order to obtain sense and antisense RNA probes by in vitro transcription. This specific probe has been used to quantify STAT5b mRNA levels in liver from male rats, by a soluiiori hybridization RNAase protection assay.Se describe la estrategia empleada para clonar, en un vector de expresión, un fragmento de 306 pb del gen de STAT5b de rata, amplificado por la técnica de RT-PCR. Se amplificó una región en el terminal 3' donde se encuentra la mayor diferencia entre las secuencias del cADN de las isoformas STAT5a y STAT5b de rata. La clonación se logró utilizando el nuevo sistema TOPO-TA recomendado para productos de dificil clonación. El fragmento se subclonó en el vector pBlueScript II SK y se caracterizó mediante secuenciación y análisis de restricción. La subclonación se realizó con el propósito de poder obtener sondas sentido y antisentido de ARN por transcripción in vitro. Esta sonda específica se empleó para cuantificar niveles de mARN de STAT5b en hígado de ratas macho mediante la técnica de hibridización en solución o ensayo de protección de ARNasas
Taming singularities of the quantum Fisher information
Quantum Fisher information matrices (QFIMs) are fundamental to estimation theory: they encode the ultimate limit for the sensitivity with which a set of parameters can be estimated using a given probe. Since the limit invokes the inverse of a QFIM, an immediate question is what to do with singular QFIMs. Moreover, the QFIM may be discontinuous, forcing one away from the paradigm of regular statistical models. These questions of nonregular quantum statistical models are present in both single- and multiparameter estimation. Geometrically, singular QFIMs occur when the curvature of the metric vanishes in one or more directions in the space of probability distributions, while QFIMs have discontinuities when the density matrix has parameter-dependent rank. We present a nuanced discussion of how to deal with each of these scenarios, stressing the physical implications of singular QFIMs and the ensuing ramifications for quantum metrology
Gut-Brain Axis: Role of Microbiota in Parkinson’s Disease and Multiple Sclerosis
It has recently been discovered that the digestive tract is lined with about 100 million nerve cells; the digestive tract has been baptized, metaphorically speaking, as “the second brain,” which contains a multitude of neurotransmitters, viruses, and bacteria that help regulate our emotional state. This second brain, known as the enteric nervous system, is a unique anatomical unit that extends from the esophagus to the anus. Like the nervous system, it produces a whole series of psychoactive substances, such as serotonin, dopamine, and opioids for pain, and synthesizes benzodiazepines. In it, we find the microbiota: a set of microorganisms (viruses and bacteria). Together with the brain, the microbiota directly influences mood, character, or sleep. Knowledge about the possible relationship of the microbiota with frequent neurological diseases is still just beginning. Recently, possible changes in the microbiota have been linked to the onset of Parkinson’s disease (PD). Also, today, we know that there are differences between the microbiota of healthy people and people with multiple sclerosis and that these differences have also been related to the disease and its evolution
A relict oasis of living deep-sea mussels Bathymodiolus and microbial-mediated seep carbonates at newly-discovered active cold seeps in the Gulf of Cádiz, NE Atlantic Ocean
Extensive beds of the deep-sea mussel Bathymodiolus mauritanicus (currently also known as Gigantidas mauritanicus) linked to active cold seeps related to fissure-like activity on Al Gacel mud volcano, Gulf of Cádiz, were filmed and sampled for the first time during the oceanographic expedition SUBVENT-2 aboard R/V Sarmiento de Gamboa. Al Gacel mud volcano is one of up to 80 fluid venting submarine structures (mud volcanoes and mud volcano/diapir complexes) identified in the Gulf of Cádiz as result of explosive venting of hydrocarbon-enriched fluids sourced from deep seated reservoirs. This mud volcano is a cone-shaped edifice, 107 m high, 944 m in diameter constituted by mud breccias and, partially covered by pavements of seep carbonates. Extensive beds of this deep-sea mussel were detected at the northern flank at 810–815 m water depth associated with bacterial mats around intermittent buoyant vertical bubble methane plumes. High methane concentrations were measured in the water column above living mussel beds. Other chemosymbiotic species (Siboglinum sp., Solemya elarraichensis, Isorropodon sp., Thyasira vulcolutre and Lucinoma asapheus) were also found in different parts of Al Gacel mud volcano. Al Gacel mud volcano may currently represent one of the most active mud volcanoes in the Gulf of Cádiz, delivering significant amounts of thermogenic hydrocarbon fluids which contribute to foster the extensive chemosynthesis-based communities detected. This finding is of paramount importance for linking extremophile bivalve populations along the North Atlantic, including cold seeps of the Gulf of México, hydrothermal vents of the Mid-Atlantic Ridge and now, detailed documented at the Gulf of Cádiz.Versión del edito
Multiple Sclerosis and Its Relationship with Oxidative Stress, Glutathione Redox System, ATPase System, and Membrane Fluidity
Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS) with a focus on inflammation, demyelination, and damage to axons leading to neurological deficits. MS pathology is associated with excessive reactive oxygen species (ROS) and generation of reactive nitrogen species (RNS), causing oxidative/nitrosative stress. Deregulation of glutathione homeostasis and alterations in glutathione‐dependent enzymes are implicated in MS. Reactive oxygen species enhance both monocyte adhesion and migration across brain endothelial cells. In addition, ROS can activate the expression of the nuclear transcription factor‐kappa, which upregulates the expression of many genes involved in MS, such as tumor necrosis factor‐α and nitric oxide synthase, among others, leading to mitochondrial dysfunction and energy deficits that result in mitochondrial and cellular calcium overload. Loss of mitochondrial membrane potential can increase the release of cytochrome c, one pathway that leads to neuronal apoptosis. Clinical studies suggest that omega‐3 long‐chain polyunsaturated fatty acids (PUFAs) including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have anti‐inflammatory, antioxidant, and neuroprotective effects in MS and animal models of MS. Here, we review the relationship of oxidative stress, the glutathione redox system, the ATPase system, and membrane fluidity with the development of MS. In addition, we describe the main findings of a clinical trial conducted with relapsing‐remitting MS patients who received a diet supplemented with 4 g/day of fish oil or olive oil. The effects of PUFAs supplementation on the parameters indicated above are analyzed in this work
Nitrogen deposition in Spain : modeled patterns and threatened habitats within the Natura 2000 network
The Mediterranean Basin presents an extraordinary biological richness but very little information is available on the threat that air pollution, and in particular reactive nitrogen (N), can pose to biodiversity and ecosystem functioning. This study represents the first approach to assess the risk of N enrichment effects on Spanish ecosystems. The suitability of EMEP and CHIMERE air quality model systems as tools to identify those areas where effects of atmospheric N deposition could be occurring was tested. For this analysis, wet deposition of NO₃− and NH₄+ estimated with EMEP and CHIMERE model systems were compared with measured data for the period 2005-2008 obtained from different monitoring networks in Spain. Wet N deposition was acceptably predicted by both models, showing better results for oxidized than for reduced nitrogen, particularly when using CHIMERE. Both models estimated higher wet deposition values in northern and northeastern Spain, and decreasing along a NE-SW axis. Total (wet + dry) nitrogen deposition in 2008 reached maxima values of 19.4 and 23.0 kg N ha¯¹ year¯¹ using EMEP and CHIMERE models respectively. Total N deposition was used to estimate the exceedance of N empirical critical loads in the Natura 2000 network. Grassland habitats proved to be the most threatened group, particularly in the northern alpine area, pointing out that biodiversity conservation in these protected areas could be endangered by N deposition. Other valuable mountain ecosystems can be also threatened, indicating the need to extend atmospheric deposition monitoring networks to higher altitudes in Spain
Diastolic shock index and clinical outcomes in patients with septic shock
Background: Loss of vascular tone is a key pathophysiological feature of septic shock. Combination of gradual diastolic hypotension and tachycardia could reflect more serious vasodilatory conditions. We sought to evaluate the relationships between heart rate (HR) to diastolic arterial pressure (DAP) ratios and clinical outcomes during early phases of septic shock. Methods: Diastolic shock index (DSI) was defined as the ratio between HR and DAP. DSI calculated just before starting vasopressors (Pre-VPs/DSI) in a preliminary cohort of 337 patients with septic shock (January 2015 to February 2017) and at vasopressor start (VPs/DSI) in 424 patients with septic shock included in a recent randomized controlled trial (ANDROMEDA-SHOCK; March 2017 to April 2018) was partitioned into five quantiles to estimate the relative risks (RR) of death with respect to the mean risk of each population (assumed to be 1). Matched HR and DAP subsamples were created to evaluate the effect of the individual components of the DSI on RRs. In addition, time-course of DSI and interaction between DSI and vasopressor dose (DSI*NE.dose) were compared between survivors and non-survivors from both populations, while ROC curves were used to identify variables predicting mortality. Finally, as exploratory observation, effect of early start of vasopressors was evaluated at each Pre-VPs/DSI quintile from the preliminary cohort. Results: Risk of death progressively increased at gradual increments of Pre-VPs/DSI or VPs/DSI (One-way ANOVA, p < 0.001). Progressive DAP decrease or HR increase was associated with higher mortality risks only when DSI concomitantly increased. Areas under the ROC curve for Pre-VPs/DSI, SOFA and initial lactate were similar, while mean arterial pressure and systolic shock index showed poor performances to predict mortality. Time-course of DSI and DSI*NE.dose was significantly higher in non-survivors from both populations (repeated-measures ANOVA, p < 0.001). Very early start of vasopressors exhibited an apparent benefit at higher Pre-VPs/DSI quintile. Conclusions: DSI at pre-vasopressor and vasopressor start points might represent a very early identifier of patients at high risk of death. Isolated DAP or HR values do not clearly identify such risk. Usefulness of DSI to trigger or to direct therapeutic interventions in early resuscitation of septic shock need to be addressed in future studies
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