Air entrainment and granular bubbles produced by an impinging jet of grains into water

A jet of water entering into a pool of the same liquid can generate air entrainment and form bubbles that rapidly raise to the surface and disintegrate. Here we report the equivalent phenomenon produced by a plunging dry granular jet, so far unexplored. For grains smaller than a critical size, the granular jet entering into the pool produces air entrainment that leads to bubbles formation. The bubbles formed are covered by a shell of grains attached to the bubble air-water interface due to capillary-induced cohesion. In contrast to classical air bubbles, these "granular bubbles" are stable over time because the granular shell prevents coalescence and keeps the air encapsulated either if the bubbles rise to the surface or sink to the bottom of the pool, which is determined by the competition of the buoyant force and the weight of the assembly. Experimentally, we show how the bubble size and volume of entrained air depend on the grain size, liquid properties and jet impact velocity.Comment: 5 pages, 4 figure

Toxoplasma gondii in Meat for Human Consumption – A Brief Review of the Most Described Strategies for Its Detection and Quantification

Toxoplasmosis is a parasitic zoonotic disease widely distributed worldwide and is caused by the intracellular parasite Toxoplasma gondii. The definitive host of T. gondii is the domestic cat and the entire cat family, in which the sexual stages of the parasite develop. T. gondii can also infect a wide range of intermediate hosts, affecting most warm-blooded animals including humans. In humans, toxoplasmosis is usually asymptomatic in healthy individuals, but can develop lymphadenopathy and nonspecific symptomatology or even be fatal in infants with congenital toxoplasmosis and in immunocompromised patients. Transmission to humans is mainly through food, especially by eating undercooked meat or meat contaminated with tissue cysts. This has led to various public health organizations worldwide monitoring programs on T. gondii in animals intended for human consumption, especially in meat samples. One of the techniques employed in the laboratory is that based on the polymerase chain reaction and some of its variants, which have proven to be valuable tools for the detection of T. gondii in tissues for human consumption and many other types of biological samples. The development of different strategies for the molecular detection of T. gondii has led to the identification and quantification methodologies varying widely among laboratories. Therefore, this chapter reviews the main methods of extraction, purification, detection and quantification of T. gondii DNA in tissue samples from different species destined for human consumption

APROXIMACIONES REFLEXIVAS Y EMPÍRICAS EN LA GESTIÓN DE PROCESOS ADMINISTRATIVOS EN LAS MIPYMES DEL DEPARTAMENTO DE SUCRE- COLOMBIA

El presente texto tiene como finalidad analizar de manera reflexiva y empírica la gestión de procesos administrativos en las Mipymes del departamento de Sucre. Esto parte de la necesidad de una argumentación de un modelo de gestión que facilite de manera funcional y eficiente, los procesos administrativos en las Mipymes de Sucre. La metodología propuesta parte de un análisis teórico de los constructos de investigación, Gestión de procesos y en Mipymes, aplicando la bibliometría mediante el software VOSviewer. Para esta primera parte se trabajó con dos muestras bibliográficas de 14,333 documentos publicados sobre la gestión de procesos administrativos en base de datos SCOPUS, arrojando una muestra de 597 palabras claves de un total de 12748 palabras y 532 documentos publicados sobre el tema en Mipymes obteniendo una muestra de 47 palabras claves. El método aplicado es de lo general a lo particular, realizando las reflexiones a nivel general de la ciencia y luego particularizando en la Mipymes como abordaje teórico y anivel empírico en Sucre, Colombia. Entre los principales resultados se reconoce la gestión de los directivos o empresarios de las Mipymes en Sucre, identificando su idiosincrasia, prácticas comunes y formas de manejar situaciones problema. Por lo cual, el establecimiento de ventajas competitivas que le signifiquen un plus, inicia desde el cambio de paradigmas en su modelo de administración y gestión de procesos.

Indirect search for dark matter: prospects for GLAST

Possible indirect detection of neutralino, through its gamma-ray annihilation product, by the forthcoming GLAST satellite from our galactic halo, M31, M87 and the dwarf galaxies Draco and Sagittarius is studied. Gamma-ray fluxes are evaluated for the two representative energy thresholds, 0.1 GeV and 1.0 GeV, at which the spatial resolution of GLAST varies considerably. Apart from dwarfs which are described either by a modified Plummer profile or by a tidally-truncated King profiles, fluxes are compared for halos with central cusps and cores. It is demonstrated that substructures, irrespective of their profiles, enhance the gamma-ray emission only marginally. The expected gamma-ray intensity above 1 GeV at high galactic latitudes is consistent with the residual emission derived from EGRET data if the density profile has a central core and the neutralino mass is less than 50 GeV, whereas for a central cusp only a substantial enhancement would explain the observations. From M31, the flux can be detected above 0.1 GeV and 1.0 GeV by GLAST only if the neutralino mass is below 300 GeV and if the density profile has a central cusp, case in which a significant boost in the gamma-ray emission is produced by the central black hole. For Sagittarius, the flux above 0.1 GeV is detectable by GLAST provided the neutralino mass is below 50 GeV. From M87 and Draco the fluxes are always below the sensitivity limit of GLAST.Comment: 14 Pages, 7 Figures, 3 Tables, version to appear on Physical Review

Asperities and barriers on the seismogenic zone in North Chile: state-of-the-art after the 2007 Mw 7.7 Tocopilla earthquake inferred by GPS and InSAR data

The Mw 7.7 2007 November 14 earthquake had an epicentre located close to the city of Tocopilla, at the southern end of a known seismic gap in North Chile. Through modelling of Global Positioning System (GPS) and radar interferometry (InSAR) data, we show that this event ruptured the deeper part of the seismogenic interface (30–50 km) and did not reach the surface. The earthquake initiated at the hypocentre and was arrested ~150 km south, beneath the Mejillones Peninsula, an area already identified as an important structural barrier between two segments of the Peru–Chile subduction zone. Our preferred models for the Tocopilla main shock show slip concentrated in two main asperities, consistent with previous inversions of seismological data. Slip appears to have propagated towards relatively shallow depths at its southern extremity, under the Mejillones Peninsula. Our analysis of post-seismic deformation suggests that small but still significant post-seismic slip occurred within the first 10 d after the main shock, and that it was mostly concentrated at the southern end of the rupture. The post-seismic deformation occurring in this period represents ~12–19 per cent of the coseismic deformation, of which ~30–55 per cent has been released aseismically. Post-seismic slip appears to concentrate within regions that exhibit low coseismic slip, suggesting that the afterslip distribution during the first month of the post-seismic interval complements the coseismic slip. The 2007 Tocopilla earthquake released only ~2.5 per cent of the moment deficit accumulated on the interface during the past 130 yr and may be regarded as a possible precursor of a larger subduction earthquake rupturing partially or completely the 500-km-long North Chile seismic gap

Identification of a novel zinc metalloprotease through a global analysis of clostridium difficile extracellular proteins

Clostridium difficile is a major cause of infectious diarrhea worldwide. Although the cell surface proteins are recognized to be important in clostridial pathogenesis, biological functions of only a few are known. Also, apart from the toxins, proteins exported by C. difficile into the extracellular milieu have been poorly studied. In order to identify novel extracellular factors of C. difficile, we analyzed bacterial culture supernatants prepared from clinical isolates, 630 and R20291, using liquid chromatography-tandem mass spectrometry. The majority of the proteins identified were non-canonical extracellular proteins. These could be largely classified into proteins associated to the cell wall (including CWPs and extracellular hydrolases), transporters and flagellar proteins. Seven unknown hypothetical proteins were also identified. One of these proteins, CD630_28300, shared sequence similarity with the anthrax lethal factor, a known zinc metallopeptidase. We demonstrated that CD630_28300 (named Zmp1) binds zinc and is able to cleave fibronectin and fibrinogen in vitro in a zinc-dependent manner. Using site-directed mutagenesis, we identified residues important in zinc binding and enzymatic activity. Furthermore, we demonstrated that Zmp1 destabilizes the fibronectin network produced by human fibroblasts. Thus, by analyzing the exoproteome of C. difficile, we identified a novel extracellular metalloprotease that may be important in key steps of clostridial pathogenesis

Guía psicopedagógica para estudiantes y profesores universitarios en el Espacio Europeo de Educación Superior

Esta Guía pone a vuestra disposición algunas de las claves de información y análisis necesarias para conocer, entender y hacer frente a las dificultades que conlleva el proceso de estudiar, aprender y formarse a lo largo de la vida. En ella podéis encontrar información acerca del EEES y ECTS, una descripción de cómo usar este recurso y toda la información de carácter académico-personal, que aparece estructurada en tres bloques: en el primer bloque, presentamos un análisis funcional de las principales variables y procesos que condicionan el ajuste a las exigencias de la vida universitaria; el segundo, contiene 25 temas relacionados con esas variables y procesos desde un punto de vista descriptivo, explicativo y preventivo. Entre los temas tratados se encuentran: hábitos de estudio: planificación y organización del tiempo, procrastinación, exámenes tipo test, técnicas de estudio, ansiedad y miedo a hablar en publico, ansiedad ante los exámenes, problemas de sueño, relaciones de pareja, orientación sexual, problemas con el alcohol, cannabis, habilidades sociales: asertividad, etc.; el tercer bloque, ofrece un conjunto de materiales de auto-evaluación, de auto-intervención y de auto-seguimiento, que pretenden serte de ayuda para mejorar tu rendimiento académico y satisfacción con los estudios. Por último, este material también cuenta con un glosario de términos de consulta para apoyarte en la comprensión de las ideas, conceptos, trucos, recomendaciones y recursos seleccionados para esta Guía.This Guide provides a useful foundation for students to know, understand and deal with the main challenges imbibed in the process of studying and learning, not only during the University years, but throughout the lifelong learning process. Inside, you can find information about the European Higher Education Area and the European Credit Transfer System, a detailed description about how to use this resource, as well as information on academic and personal issues organized into three parts. The first one contains a psychological functional analysis of the main variables and processes that determine the adjustment level of students to the challenges posed by the University life. The second one includes information, definitions, explanations and recommendations on twenty five of those main variables, factors and processes. Among others, the themes included are: Study habits and strategies like planification of tasks and organization of time, procrastination, multiple choice exam, study techniques, anxiety, exams ´anxiety, talking in public, sleep problems, couple relationships, sexual orientation, alcohol problems, cannabis, social skills, assertively, etc. The third bloc includes several examples and materials ready to be used for self-evaluation, self-intervention, and self-following up, effective to improve academic performance and personal satisfaction with your studies. Finally, a glossary with basic key terms is included to help you to better understand the ideas, concepts, tips, recommendations and resources selected for this Guide.Universidad de Granada, Vicerrectorado de Estudiante

Comprehensive study of reaction mechanisms for the Be9+Sm144 system at near- and sub-barrier energies

The delayed x-ray detection technique was used to measure complete and incomplete fusion cross sections for the $^{9}\mathrm{Be}+^{144}\mathrm{Sm}$ reaction at sub- and near-barrier energies. Elastic and inelastic scattering for this system were also measured. Reaction cross sections were derived and the transfer cross sections of one neutron were calculated. The suppression of complete fusion above the barrier, of the order of 10%, is attributed to $^{9}\mathrm{Be}$ breakup and is considerably smaller than the value of 30% found for the $^{9}\mathrm{Be}+^{208}\mathrm{Pb}$ system