Present situation of the autochthonous donkey population in Spain

A study of the present census and administrative situation has been studied also the possibilities of conservation has been analysed During the last 5 years the donkey census has increased because the consideration like a breed in danger of extinction. There are several initiatives looking for the consolidation of the autochthonous breeds of donkeys in Spain but most of them are less important and very isolated. Except for these conservation initiatives, the donkey breeds be considered in a serious danger of extinction.Se realiza un estudio de la situación actual censal y administrativa de las razas asnales españolas y se analizan sus posibilidades y perspectivas de conservación Queda reflejado cómo en los últimos 5 años se ha producido un aumento en los efectivos asnales como respuesta a las diferentes acciones de sensibilización con respecto a las razas en peligro de extinción. No faltan iniciativas que adaptándose a los nuevos tipos de demanda busquen soluciones para la consolidación de nuestras razas autóctonas asnales aunque aún muchas de ellas son discretas y localizadas. Fuera del ámbito esas actuaciones el panorama no se muestra muy alentador

3D photonic crystals from highly monodisperse FRET-based red luminescent PMMA spheres

Red-luminescent PMMA spheres containing a Förster resonance energy transfer (FRET) pair were synthesized via a two-step polymerization method. Two reaction parameters, time and monomer volume, are scanned in order to tune the sphere diameter in the 250-500 nm range. Further the polydispersity of the spheres is kept low, at ca. 3%, regardless of sphere diameter or dye concentration. A thorough optical characterization via spectroscopy and time resolved measurements shows a FRET efficiency of over 40% before concentration quenching effects take place, allowing for a precise tuning of their emission in the red region of the visible spectrum. The high quality of these spheres makes them suitable to fabricate self-assembled 3D photonic crystals which act as photonic environment to modify the spectral properties of the FRET pair via Bragg diffraction.España Mineco MAT2012-31659Comunidad de Madrid S2013/MIT-274

Optical amplification enhancement in photonic crystals

Improving and controlling the efficiency of a gain medium is one of the most challenging problems of laser research. By measuring the gain length in an opal based photonic crystal doped with laser dye, we demonstrate that optical amplification is more than twenty-fold enhanced along the Gamma-K symmetry directions of the face centered cubic photonic crystal. These results are theoretically explained by directional variations of the density of states, providing a quantitative connection between density of the states and light amplification

Overcharging: The Crucial Role of Excluded Volume

In this Letter we investigate the mechanism for overcharging of a single spherical colloid in the presence of aqueous salts within the framework of the primitive model by molecular dynamics (MD) simulations as well as integral-equation theory. We find that the occurrence and strength of overcharging strongly depends on the salt-ion size, and the available volume in the fluid. To understand the role of the excluded volume of the microions, we first consider an uncharged system. For a fixed bulk concentration we find that upon increasing the fluid particle size one strongly increases the local concentration nearby the colloidal surface and that the particles become laterally ordered. For a charged system the first surface layer is built up predominantly by strongly correlated counterions. We argue that this a key mechanism to produce overcharging with a low electrostatic coupling, and as a more practical consequence, to account for charge inversion with monovalent aqueous salt ions.Comment: 7 pages, 3 figs (4 EPS files). To appear in Europhysics Letter

Un modelo de riesgo de credito basado en opciones compuestas con barrera. Aplicacion al mercado continuo espanol

In this work the valuation methodology of compound option written on a downand-out call option, developed by Ericsson and Reneby (2003), has been applied to deduce a credit risk model. It is supposed that the firm has a debt structure with two maturity dates and that the credit event takes place when the assets firm value falls under a determined level called barrier. An empirical application of the model for 105 firms of Spanish continuous market is carried out. For each one of them its value in the date of analysis, the volatility and the critical value are obtained and from these, the default probability to short and long-term and the implicit probability in the two previous probabilities are deduced. The results are compared with the ones obtained from the Geske model (1977).structural approach, compound barrier option, credit risk, default probability

Valoracion de credit default swaps: Una aplicacion del modelo de Hull-White al mercado espanol

An empirical application of Hull-White model (2000) to the Spanish market is presented. This model provides an expression to calculate the payment made by credit default swap (CDS) buyer when there is no counterparty default risk. Moreover, it is assumed that the yield par curve, the recovery rate (that is constant) and the moment of credit event are independent. Data from Banco Santander Central Hispano bonds are used to calculate risk neutral default probability and then CDS premia for an underlying bond of the same credit rating are calculated. This premia are computed under no arbitrage arguments and are compared with the market credit spreads. This results show that the model premia are similar to credit spreads and the main conclusion of this paper is that Hull-White model is suitable to obtain the CDS premia in Spanish market.credit risk, credit event, default probability, swaps

Caloric restriction, physical exercise, and CB1 receptor blockade as an efficient combined strategy for bodyweight control and cardiometabolic status improvement in male rats

Obesity is critically associated with the development of insulin resistance and related cardiovascular and kidney diseases. Several strategies for weight loss have been developed but most of them exhibit a post-intervention rebound effect. Here, we aimed to design combined weight-loss strategies of caloric restriction, physical exercise, and administration of a CB1 receptor blocker to inhibit food intake that also accomplish the objectives of lost-weight maintenance and improvement of cardiovascular and renal function. Diet-induced obesity (DIO) was generated in Sprague Dawley rats for 12 weeks to test the effects of single or combined strategies (i.e. caloric restriction, mixed training protocol, and/or administration of appetite suppressant) on caloric intake, body weight, cardiovascular and renal functionality resulting from a weight-loss intervention period of 3 weeks followed by 6 weeks of weight maintenance. Consumption of a high-fat diet (HFD) caused a significant increase in body weight (5th week of the experimental period) and led to the development of insulin resistance, cardiovascular, and renal alterations. The different interventions tested, resulted in a significant body weight loss and improved glucose metabolism, aerobic capacity, electrocardiographic parameters, vascular expression of adhesion molecules and inflammatory mediators, and renal functionality, reaching values similar to the control normocaloric group or even improving them. Successful maintenance of lost weight was achieved along a 6-week maintenance period in addition to adequate health status. In conclusion, the weight-loss and maintenance intervention strategies tested were efficient at reversing the obesity-related alterations in body weight, glucose metabolism, aerobic capacity, cardiovascular and renal functionality. The beneficial action was very consistent for caloric restriction and physical exercise, whereas administration of a CB1 receptor blocker complemented the effects of the prior interventions in some parameters like body weight or aerobic capacity, and showed specific actions in renal status, increasing glomerular filtration rate and diuresis. Overall, the novelty of our study relies on the easy implementation of combined strategies for effective weight management that resulted in significant health benefits.Spanish Ministry of Science, Innovation and UniversitiesEuropean Commission DEP2014-58296-R RTC-2017-6540-1 RTI2018-100934-B-I00European Commissio

Bioinspired Synthesis of Platensimycin from Natural ent-Kaurenoic Acids

Ministerio de Economía y Competitividad, PID2019-106222RB-C32/SRA (State Research Agency, 10.13039/501100011033)Universidad de Granada/CBU