Weak localization and electron-electron interaction in the layered compound CuFeTe2

The study of the electrical properties of the layered compound CuFeTe2 shows that there are three well differentiated conduction regimes depending on the temperature. Below TSDW ~ 300 K the formation of a Spin Density Wave (SDW) state has been reported, in the frame of a metal to non metal transition. Below 100 K (~ TSDW/3) the behavior of the electrical resistance as a function of temperature and magnetic field is attributable to the still present not condensed electrons (quasi particles) in the SDW state. At low temperatures (1.8 - 20K), low current (< 1 mA) and magnetic eld (0<H <6 Tesla), the effects of weak localization and electronic interactions in two dimensions appear. At intermediate temperatures (20 < T < 100 K) a hopping conductivity behavior is observed

Soil erosion in vineyard under intense rainfall events

Abstract: S imulated rainfall experiments (68.2 mm h -1 ) on plots of 1 m 2 on two vineyards in Utiel and Moixent show high soil erosion rates. These measuremen ts show that runoff rates and sediment concentration are very high due to the bare soils. Soil losses are 5.68 and 23.14 Mg ha -1 h -1 , respectively, in the study areas and Moixent and Utie l. It is confirmed that the vineyards contribute to highly erodible soils.Unión Europea GL2008-02879/BTEUnión Europea LEDDRA 243857Unión Europea RECARE FP7 60349

Low and high Reynolds number flows inside Taylor cones

Liquid motions inside Taylor cones exhibit interesting features which are not well understood yet. In addition to the flow rate injected through the electrified needle to which the conical meniscus is anchored, the action of the tangential electrical stress on the cone surface induces a recirculating meridional motion, towards the apex along the generatrix and away from it along the axis. Sometimes, a vigorous swirl is observed. The characteristic value of the liquid velocity is found to be highly dependent on both the electrical conductivity and the viscosity of the liquid, so that the Reynolds number of the liquid flow varies from very small values (creeping flow) for the case of highly conducting and viscous liquids to relatively large values for liquids with sufficiently low values of the liquid conductivity and viscosity. Theoretical conical flows for low and high values of the Reynolds number show qualitatively good agreement with photographs of real flows inside Taylor cones. In particular, the existence of a vigorous swirl which is observed in the electrospraying of paraffins and other poorly conducting and low viscosity liquids can be explained as bifurcation of a primarily nonswirling meridional flow when the Reynolds number reaches a critical value.Comisión Interministerial de Ciencia y Tecnología PB96-0679-C02-0

Torres Quevedo's mechanical calculator for second-degree equations with complex coefficients

Leonardo Torres Quevedo worked intensively in analogue calculating machines during the last years of the 19th century. The algebraic calculators were calculating machines in which numbers are represented by quantities of a given physical magnitude(s). The physical result is a magnitude of a physical quantity whose measurement in the coherent unit is the result of the algebraic equation. This article shows the three-dimensional (3D) modelling, virtual reconstruction and simulation of the first mechanical calculating machine for solving second-degree equations with complex coefficients, to prove that the functionality was correct and the machine could be built. Sketches of said machine provide enough information on the shape and mechanisms of the machine. By means of the simulation, it has been possible to prove its operation and feasibility of construction so that it is possible to replicate it as a real physical model. The mechanical calculator for second-degree equations with complex coefficients constituted a major milestone in the technological development of the time and helped to originate and improve the design of other algebraic calculators like the machine for solving eighth-degree equations

Seasonal variability of gelatinous zooplankton during an anomalously warm year at Cabo Pulmo national park, Mexico

The seasonal variability of gelatinous zooplankton (siphonophores, medusae, and thaliaceans) abundance was investigated at Cabo Pulmo National Park (CPNP) from weekly zooplankton samples collected throughout 2014. The Gulf of California had prolonged warming during 2009-2019, with 2014 as the anomalously warm year preceding El Niño 2015-2016 compared to the 2003-2020 SST time series. Gelatinous zooplankton accounted <1% of the entire zooplankton community abundance at CPNP during 2014, suggesting a low influence of predation pressure upon their zooplanktonic and micronekton preys. Siphonophores (57%), thaliaceans (42%), and medusae (1%) were present throughout the year. The abundance of gelatinous zooplankton had a significant negative association with sea surface temperature and a positive association with sea surface chlorophyll-a concentration and velocity and direction of the wind, increasing their abundance during October after the hurricane season. The gelatinous zooplankton species assemblage at the coastal CPNP was similar but less abundant than the gelatinous zooplankton species assemblage observed in the oceanic region of the southern Gulf of California during summer 2014. Tropical species Diphyes dispar, Abylopsis tetragona, Chelophyes contorta, and Thalia spp. numerically dominated the gelatinous zooplankton community associated with a regional heatwave period recorded during 2014. A high proportion of tropical zooplankton indicates that mesotrophic conditions sustain the current high biomass and diversity of nektonic and benthonic planktophagous fauna inhabiting CPNP. However, prolonged warming events might decrease zooplankton biomass in the southern region of the Gulf of California in the future.Fil: Silveyra Bustamante, Angel Antonio. Instituto Politécnico Nacional; MéxicoFil: Gómez Gutiérrez, Jaime. Instituto Politécnico Nacional; MéxicoFil: González Rodríguez, Eduardo. Consejo Nacional de Ciencia y Tecnologia de Mexico. Centro de Investigacion Cientifica y de Educacion Superior de Ensenada Baja California.; MéxicoFil: Sánchez, Carlos. Universidad Autónoma de Baja California Sur; MéxicoFil: Schiariti, Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Mendoza Becerril, María A.. Consejo Nacional de Ciencia y Tecnología; Méxic

Psychosocial status of Physical Education teachers according to socio-demographic characteristics

Actualmente, los docentes están expuestos a riesgos psicosociales propios del contexto educativo y es importante superar y anticiparse a las adversidades que ello conlleva. Por ello, este estudio pretende analizar los niveles de estrés, síndrome de burnout y resiliencia en profesores de educación física, así como establecer las relaciones existentes en función del género y la situación sociolaboral. El estudio tuvo un diseño no experimental, descriptivo, comparativo y correlacional, con medición en un solo grupo. La muestra estuvo compuesta por 415 profesores de educación física de toda España, con un rango de edad de 21-53 años (M=28,78±6,15) y una distribución heterogénea, representando el 69,4% del género masculino y el 30,6% del género femenino. Para registrar los aspectos sociodemográficos se utilizó la Escala de Estrés Percibido (PSS), el Inventario de Burnout de Maslach (MBI), la Escala de Resiliencia de Connor-Davidson (CD-RISC) y un cuestionario Ad- Hoc. Finalmente se observa que, para el síndrome de burnout, la subescala con mayor puntuación es el agotamiento emocional, seguida de la realización personal y la despersonalización. Para la resiliencia, se observa que la subescala con mayor puntuación es la competencia personal, seguida de la aceptación positiva, el control y el propósito, la tolerancia a los acontecimientos negativos y las influencias espirituales.Currently, teachers are exposed to psychosocial risks specific to the educational context and it is important to overcome and anticipate the adversities involved. Therefore, this study aims to analyse the levels of stress, burnout syndrome and resilience in physical education teachers, as well as to establish the existing relationships according to gender and sociooccupational situation. The study had a non-experimental, descriptive, comparative and correlational design, with measurement in a single group. The sample consisted of 415 physical education teachers from all over Spain, with an age range of 21-53 years (M=28.78±6.15) and a heterogeneous distribution, representing 69.4% of the male gender and 30.6% of the female gender. The Perceived Stress Scale (PSS), the Maslach Burnout Inventory (MBI), the Connor-Davidson Resilience Scale (CD-RISC) and an Ad-Hoc questionnaire were used to record socio-demographic aspects. Finally, it is observed that, for burnout syndrome, the subscale with the highest score is emotional exhaustion, followed by self-fulfilment and depersonalisation. For resilience, the highest scoring subscale is personal competence, followed by positive acceptance, control and purpose, tolerance of negative events and spiritual influences

Seroprevalencia de las infecciones por el virus Diarrea Vírica Bovina en ganado bovino en Andalucía

Se ha realizado un estudio seroepidemiológico frente al virus de la Diarrea Vírica Bovina (vDVB) en la cabaña bovina andaluza, utilizando para ello un ELISA indirecto para la detección de anticuerpos frente a una proteína altamente conservada (p80). Después de eliminar los animales vacunados, la encuesta se realizó sobre 4.768 individuos pertenecientes a 227 colectivos no vacunados frente al vDVB, mediante muestreo estadístico para un nivel de confianza del 95 por ciento. La seropositividad obtenida ha sido del 42,3 por ciento de los individuos analizados, mientras que la prevalencia estimada de rebaños seropositivos alcanzó el 70,9 por ciento. La proporción de bovinos persistentemente infectados (IP) encontrada en la muestra (0,063 % de los individuos y 1,32 de los colectivos), ha sido más baja de la esperada en función de la alta seroprevalencia detectada, hecho que demuestra que la supervivencia de estos animales lógicamente está condicionada

Regeneración de la planta de papa (Solanum Tuberosum L.) In Vitro a partir del estolón

El crecimiento poblacional y el incremento en la demanda de vegetales para satisfacer los requerimientos nutrimentales de la propia población son cada vez m·s altos, tal es el caso de la papa (Sola- num tuberosum L.). Al no existir la cantidad de pro- ducto con la calidad necesaria para consumo hu- mano e industrial, se hace necesario implementar mecanismos para incrementar la producciÛn. Se realizaron estudios para encontrar el medio de cultivo adecuado para desarrollar la tuberizaciÛn in vitro. Se emplearon esquejes de tallo y estolones de plantas provenientes de invernadero e in vitro. Los esquejes se mantuvieron por espacio de 30 dÌas en condiciones de iluminaciÛn. Los resultados demos- traron que es posible regenerar la planta de papa a partir de estolón, siempre y cuando provenga de esquejes in vitro, puesto que los que provienen de plantas de invernadero mostraron una fuerte ten- dencia a formar tubÈrculos, en medio MS con 8% de sacarosa, 1/10 de la concentración normal de nitratos y en ausencia de GA3. Los mejores tubÈrcu- los obtenidos correspondieron a los tubÈrculos in- ducidos bajo iluminaciÛn procedentes de pl·ntulas in vitro. El an·lisis electroforÈtico de proteÌnas por medio de SDS-PAGE mostro la presencia de patatina (40-45 kDa) particularmente en plántulas in vitro. Mediante Western blot se logro identificar la pre- sencia de proteÌnas de aproximadamente 18 kDa, en tubÈrculos almacenados durante 30 dÌas