Downstream-migrating antidunes in sand, gravel and sand-gravel mixtures

River hydrodynamicsBed roughness and flow resistanc

Filogenia molecular y estimación del tiempo de divergencia en pennatuláceos (Cnidaria: Octocorallia: Pennatulacea)

Pennatulaceans are an important component of benthic marine communities usually related to soft bottoms. Despite their important ecological role, as yet little is known about their origin and divergence time. The first attempts to establish phylogenetic relationships among genera date from the early 20th century, when only morphological characters were available. In the last decade, phylogenetic analyses based on mitochondrial DNA sequences from a selected number of species have proposed a different hypothetical ancestor for this group, but their intergeneric relationships remain obscure. The present study is based on a combination of mitochondrial and nuclear markers (mtMutS, Cox1 and 28S rDNA), adding new molecular information about the phylogenetic relationships among the pennatulacean genera, including 38 new sequences belonging to 13 different species. Some of the phylogenetic relationships inferred in the present study question the current classification of sea pens based on morphology (at different taxonomic levels), clearly indicating that the two main groups Sessiliflorae and Subselliflorae, some of their main families (e.g. Pennatulidae, Umbellulidae, Virgulariidae) and some genera (e.g. Umbellula, Veretillum) are non-monophyletic. In addition, the veretillids, traditionally considered the most primitive pennatulaceans, are not shown as the earliest-diverging taxon. Moreover, an analysis of divergence time performed here suggested that the origin of the pennatulaceans dates from the Lower Cretaceous (Berriasian, ~144 Ma), in agreement with their sparsely known fossil record, while the initial divergence of most extant genera occurred in the Oligocene and Miocene times.Los pennatuláceos son un componente importante de las comunidades bentónicas marinas generalmente relacionados con fondos blandos. A pesar de su importante papel ecológico, la información sobre su origen y tiempo de divergencia es aún escasa. Los primeros intentos de establecer relaciones filogenéticas entre géneros datan de principios del siglo XX, cuando sólo estaban disponibles caracteres morfológicos. En la última década, los análisis filogenéticos basados en secuencias de ADN mitocondrial procedentes de un limitado número de especies han propuesto un ancestro hipotético diferente para este grupo, pero sus relaciones intergenéricas permanecen oscuras. La presente investigación está basada en una combinación de marcadores mitocondriales y nuclear (mtMutS, Cox1 y ADNr 28S), aportando nueva información molecular sobre las relaciones filogenéticas entre los géneros de pennatuláceos, incluyendo 38 nuevas secuencias pertenecientes a 13 especies. Algunas de las relaciones filogenéticas inferidas en el presente estudio cuestionan la actual clasificación de las plumas de mar basada en la morfología (a diferentes niveles taxonómicos), indicando claramente que los dos grupos principales Sessiliflorae y Subselliflorae, algunas de sus principales familias (por ejemplo Pennatulidae, Umbellulidae, Virgulariidae) y algunos géneros (por ejemplo Umbellula, Veretillum) son no-monofiléticos. Asimismo, los veretílidos, tradicionalmente considerados los pennatuláceos más primitivos, no se muestran como el taxón divergente más antiguo. Además, un análisis del tiempo de divergencia realizado en este trabajo sugirió que el origen de los pennatuláceos data del Cretácico Inferior (Berriasiano, ~ 144 Ma), de acuerdo con su escasamente conocido registro fósil, mientras que la divergencia inicial de la mayoría de los géneros existentes ocurrió en tiempos del Oligoceno y Mioceno

Influence of Feeding Enzymatically Hydrolyzed Yeast Cell Wall on Growth Performance and Digestive Function of Feedlot Cattle during Periods of Elevated Ambient Temperature.

In experiment 1, eighty crossbred steers (239±15 kg) were used in a 229-d experiment to evaluate the effects of increasing levels of enzymatically hydrolyzed yeast (EHY) cell wall in diets on growth performance feedlot cattle during periods of elevated ambient temperature. Treatments consisted of steam-flaked corn-based diets supplemented to provide 0, 1, 2, or 3 g EHY/hd/d. There were no effects on growth performance during the initial 139-d period. However, from d 139 to harvest, when 24-h temperature humidity index averaged 80, EHY increased dry matter intake (DMI) (linear effect, p<0.01) and average daily gain (ADG) (linear effect, p = 0.01). There were no treatment effects (p>0.10) on carcass characteristics. In experiment 2, four Holstein steers (292±5 kg) with cannulas in the rumen and proximal duodenum were used in a 4×4 Latin Square design experiment to evaluate treatments effects on characteristics of ruminal and total tract digestion in steers. There were no treatment effects (p>0.10) on ruminal pH, total volatile fatty acid, molar proportions of acetate, butyrate, or estimated methane production. Supplemental EHY decreased ruminal molar proportion of acetate (p = 0.08), increased molar proportion of propionate (p = 0.09), and decreased acetate:propionate molar ratio (p = 0.07) and estimated ruminal methane production (p = 0.09). It is concluded that supplemental EHY may enhance DMI and ADG of feedlot steers during periods of high ambient temperature. Supplemental EHY may also enhance ruminal fiber digestion and decrease ruminal acetate:propionate molar ratios in feedlot steers fed steam-flaked corn-based finishing diets

Tratamiento quirúrgico de las roturas del tendón de Aquiles

El objetivo del trabajo fue valorar los resultados y complicaciones obtenidos tras tratamiento quirúrgico de las rupturas subcutáneas del tendón de Aquiles. Se revisaron 26 pacientes, con un seguimiento mínimo de 1 año. Detallamos nuestra metodología en cuanto a técnica quirúrgica y manejo postoperatorio. Se valoró el resultado clínico según los siguientes parámetros: movilidad de tobillo, potencia muscular tríceps, engrosamiento tendinoso, claudicación a la marcha, atrofia gemelar, incorporación a actividades deportivas y alteraciones residuales. Los resultados fueron muy buenos en 21 casos (80,7%); buenos en 5 (19,3%), y ningún caso con resultado regular o malo. Destacamos 5 complicaciones postoperatorias inmediatas y 1 caso de reruptura, con resultado final satisfactorio. Dados los buenos resultados obtenidos, recomendamos el tratamiento quirúrgico en pacientes activos, con buen estado general, independientemente de la edad.The objective of this work was to asess the clinical results and complications with the surgical treatment for subcutaneous Achilles tendon ruptures. Twenty six patients were clinically revised with a minimal follow up of one year. We detailed the surgical technique and postoperative management of the patients. Clinical results were assessed with the next parameters: ankle joint motion; triceps muscle strength; Achilles tendinous thickened; walking limp; triceps muscle atrophy, possibility of sports practice and definitive changes. We had excellent results in 21 cases (80,7%); good results in 5 cases (19,3%) and none with fair or poor results. We detached 5 cases with immediate postoperative complications and one case of relapse, all of them with good clinical result. Our excellent and good clinical results with the surgical technique for the Achilles tendon ruptures allow us to recommend this treatment in active patients, with appropriate health conditions in spite of the age

Stochastic reserving with a stacked model based on a hybridized Artificial Neural Network

Currently, legal requirements demand that insurance companies increase their emphasis on monitoring the risks linked to the underwriting and asset management activities. Regarding underwriting risks, the main uncertainties that insurers must manage are related to the premium sufficiency to cover future claims and the adequacy of the current reserves to pay outstanding claims. Both risks are calibrated using stochastic models due to their nature. This paper introduces a reserving model based on a set of machine learning techniques such as Gradient Boosting, Random Forest and Artificial Neural Networks. These algorithms and other widely used reserving models are stacked to predict the shape of the runoff. To compute the deviation around a former prediction, a log-normal approach is combined with the suggested model. The empirical results demonstrate that the proposed methodology can be used to improve the performance of the traditional reserving techniques based on Bayesian statistics and a Chain Ladder, leading to a more accurate assessment of the reserving risk

A survey of the genera Sarcodictyon Forbes, 1847, and rolandia Lacaze-Duthiers, 1900, (anthozoa: octocorallia) in the North-eastern Atlantic and the Mediterranean

Sarcodictyon catenatum Forbes, 1847, is a common species in the Atlantic and the Mediterranean. However, often it has been mistaken for Rolandia coralloides Lacaze-Duthiers, 1900. On the basis of British and Mediterranean material we studied the main characters for distinguishing S. catenatum. We consider Rolandia coralloides Lacaze-Duthiers, 1900, to be a valid species and we assign to it all the material named Rolandia rosea by S. Weinberg (1978). Furthermore, a histological study confirmed that R. coralloides typically forms groups of polyps embedded in a common coenenchyme. Therefore, the possibility of transferring R. coralloides from Stolonifera to Alcyonacea is discussed. Evagorgia rosea Philippi, 1842, is here considered to be a nomen dubium

Metal-Insulator Transition in the Two-Dimensional Hubbard Model at Half-Filling with Lifetime Effects within the Moment Approach

We explore the effect of the imaginary part of the self-energy, $Im\Sigma(\vec{k},\omega)$, having a single pole, $\Omega(\vec{k},\omega)$, with spectral weight, $\alpha(\vec{k})$, and quasi-particle lifetime, $\Gamma(\vec{k})$, on the density of states. We solve the set of parameters, $\Omega(\vec{k},\omega$), $\alpha(\vec{k})$, and $\Gamma(\vec{k})$ by means of the moment approach (exact sum rules) of Nolting. Our choice for $\Sigma(k,\omega)$, satisfies the Kramers - Kronig relationship automatically. Due to our choice of the self - energy, the system is not a Fermi liquid for any value of the interaction, a result which is also true in the moment approach of Nolting without lifetime effects. By increasing the value of the local interaction, $U/W$, at half-filling ($\rho = 1/2$), we go from a paramagnetic metal to a paramagnetic insulator, (Mott metal - insulator transition ($MMIT$)) for values of $U/W$ of the order of $U/W \geq 1$ ($W$ is the band width) which is in agreement with numerical results for finite lattices and for infinity dimensions ($D = \infty$). These results settle down the main weakness of the spherical approximation of Nolting: a finite gap for any finite value of the interaction, i.e., an insulator for any finite value of $U/W$. Lifetime effects are absolutely indispensable. Our scheme works better than the one of improving the narrowing band factor, $B(\vec{k})$, beyond the spherical approximation of Nolting.Comment: 5 pages and 5 ps figures (included

La raza sayaguesa base de la marca silomaña. Actualidad y posibilidades

La utilización de los pastos de la montaña de León unido a una raza autóctona, la raza sayaguesa, para la obtención de un producto de calidad y diferenciado como es el buey. Nos ha permitido obtener un producto de unas características hasta ahora desconocidas, con un perfil de ácidos grasos mono y poliinsaturados, y unas características físico-químicas que hacen que nuestro producto puede considerarse como un “ALIMENTO FUNCIONAL”