Estudio comparativo de equipos fijos de pedestal y su aplicación en la detección del tráfico incontrolado de material radiactivo en aeropuertos

En este trabajo se analiza la respuesta de tres equipos comerciales, diseñados para detectar el tráfico ilícito o el desplazamiento involuntario de material radiactivo en aeropuertos cuando es transportado por los pasajeros. Se han comparado tres instrumentos fijos de pedestal: el equipo APM de Bicron, el equipo GR-606 de Exploranium y el equipo FHT-1372 de Thermo Eberline. En esta evaluación inicial, realizada en el Laboratorio de Ingeniería Nuclear de la Escuela de Caminos, Canales y Puertos, se observó que el equipo FHT-1372 presentó una respuesta de detección más rápida, sensible y permitió la medida de tasa de dosis total y tasa de dosis artificial. Este equipo fue instalado en la salida de la aduana de pasajeros del aeropuerto internacional de Barajas durante un periodo operativo de 108 días en el año 2002 y pasaron un total de 1.339.931 personas. Este periodo se dividió en 5 sesiones para poder establecer los niveles de investigación adecuados para detectar una posible incidencia de material radiactivo, que finalmente se fijaron en 110 nSv/h para la tasa de dosis total y 25 nSv/h para la tasa de dosis artificial. Durante dicho periodo se detectaron 39 posibles incidencias por encima del límite de investigación establecido para las diferentes sesiones, 5 de ellas con un valor 10 veces superior al fondo ambiental de la sala donde se instaló el equipo (alrededor de 90 nSv/h) y ninguna superó el nivel de 100 μSv/h a 1 m de distancia que la Organización Internacional de la Energía Atómica (OIEA) establece como límite para el transporte lícito de material radiactivo

Mercury: Risks and Handling as Hazardous Waste

The handling of some chemical substances, as is the case of Mercury used in the determination of the contraction characteristics of soils, becomes dangerous waste at the end of the test process, which requires an adequate management having as a reference the established measures in the legislation and complying with the legal and applicable requirements in this matter. In the present work the characteristics of the mercury, the measures for its use, transportation, and/or storage, as well as the risks to the occupationally exposed workers, are related in the Laboratories of the Applied Research Company. The objective of this research is to raise the culture in the procedures for the handling of chemical substances and hazardous waste, in the use and care of the means of individual protection, as well as compliance with everything established in the procedures for the realization of activities related to the use of mercury to form an environmental awareness focused on achieving an excellent quality of life in the workplace and contribute to the protection of the environment

One strategy does not fit all: determinants of urban adaptation in mammals

Urbanisation exposes wildlife to new challenging conditions and environmental pressures. Some mammalian species have adapted to these novel environments, but it remains unclear which characteristics allow them to persist. To address this question, we identified 190 mammals regularly recorded in urban settlements worldwide, and used phylogenetic path analysis to test hypotheses regarding which behavioural, ecological and life history traits favour adaptation to urban environments for different mammalian groups. Our results show that all urban mammals produce larger litters; whereas other traits such as body size, behavioural plasticity and diet diversity were important for some but not all taxonomic groups. This variation highlights the idiosyncrasies of the urban adaptation process and likely reflects the diversity of ecological niches and roles mammals can play. Our study contributes towards a better understanding of mammal association to humans, which will ultimately allow the design of wildlife-friendly urban environments and contribute to mitigate human-wildlife conflicts

Temporal changes of the flare activity of Proxima Cen

We study temporal variations of the emission lines of Halpha, Hepsilon, H and K Ca II, D1 and D2 Na I, 4026 and 5876 A He I in the HARPS spectra of Proxima Centauri across an extended time of 13.2 years, from May 27, 2004, to September 30, 2017. Aims. We analyse the common behaviour and differences in the intensities and profiles of different emission lines in flare and quiet modes of Proxima activity. Methods. We compare the pseudo-equivalent widths (pEW) and profiles of the emission lines in the HARPS high-resolution (R ~ 115,000) spectra observed at the same epochs. Results. All emission lines show variability with a timescale of at least 10 min. The strength of all lines except He I 4026 A correlate with \Halpha. During strong flares the `red asymmetry' appears in the Halpha emission line indicating the infall of hot condensed matter into the chromosphere with velocities greater than 100 km/s disturbing chromospheric layers. As a result, the strength of the Ca II lines anti-correlates with Halpha during strong flares. The He I lines at 4026 and 5876 A appear in the strong flares. The cores of D1 and D2 Na I lines are also seen in emission. During the minimum activity of Proxima Centauri, Ca II lines and Hepsilon almost disappear while the blue part of the Na I emission lines is affected by the absorption in the extending and condensing flows. Conclusions. We see different behaviour of emission lines formed in the flare regions and chromosphere. Chromosphere layers of Proxima Cen are likely heated by the flare events; these layers are cooled in the `non-flare' mode. The self-absorption structures in cores of our emission lines vary with time due to the presence of a complicated system of inward and outward matter flows in the absorbing layers.Comment: 22 pages, 12 Figures, accepted by A

Dynamic analysis using finite elements to calculate the critical wear section of the contact wire in suburban railway overhead conductor rails

The purpose of this study is to determine the critical wear levels of the contact wire of the catenary on metropolitan lines. The study has focussed on the zones of contact wire where localised wear is produced, normally associated with the appearance of electric arcs. To this end, a finite element model has been developed to study the dynamics of pantograph-catenary interaction. The model includes a zone of localised wear and a singularity in the contact wire in order to simulate the worst case scenario from the point of view of stresses. In order to consider the different stages in the wire wear process, different depths and widths of the localised wear zone were defined. The results of the dynamic simulations performed for each stage of wear let the area of the minimum resistant section of the contact wire be determined for which stresses are greater than the allowable stress. The maximum tensile stress reached in the contact wire shows a clear sensitivity to the size of the local wear zone, defined by its width and depth. In this way, if the wear measurements taken with an overhead line recording vehicle are analysed, it will be possible to calculate the potential breakage risk of the wire. A strong dependence of the tensile forces of the contact wire has also been observed. These results will allow priorities to be set for replacing the most critical sections of wire, thereby making maintenance much more efficient. The results obtained show that the wire replacement criteria currently borne in mind have turned out to be appropriate, although in some wear scenarios these criteria could be adjusted even more, and so prolong the life cycle of the contact wire

Changes in colorectal cancer screening intention among people aged 18–49 in the United States

Background: To determine whether exposure to a peer-led intervention focused on colorectal cancer (CRC) screening, physical activity, and multi-vitamin intake can lead to increased intentions to be screened for CRC once age eligible among adults under the age of 50. Methods: Participants were residents of low-income housing sites, and CRC screening intentions were assessed at baseline and at follow-up (approximately 2 years later) to determine changes in screening intentions and factors associated with changes in intentions. Results: Participants (n = 692) were 78.4% female, 42.6% Hispanic and 50.8% black. At follow-up, 51% maintained their intention to be screened and 14.6% newly intended to get screened. Individuals newly intending to get screened were more likely to have participated in the intervention, be older, male, and born in Puerto Rico or the United States compared to those who maintained their intention not to get screened (p < 0.05). Conclusion: Exposure to CRC prevention messages before the age of 50 can increase screening intentions among individuals who did not initially intend to get screened. Peer-led interventions to promote CRC screening should include individual less than 50 years of age, as this may contribute to increased screening at the recommended age threshold

Piranoantocianos vinilfenólicos en vinos tintos utilizando levaduras HCDC+.

Los piranoantocianos vinilfenólicos son aductos de elevada estabilidad, con interesantes propiedades para la mejora del color en vinos tintos, y que se forman por condensación entre ácidos hidroxicinámicos o sus respectivos vinilfenoles y antocianos procedentes de la uva. Inicialmente se pensaba que la única ruta de formación era exclusivamente química (Schwarz, 2003) en un lento proceso a partir de ácidos hidroxicinámicos, que inducía a cantidades muy pequeñas durante el periodo de envejecimiento de los vinos tintos y podían por tanto ser usadas como age-markers. Recientemente se ha demostrado (Morata et al, 2006 y 2007) que algunas cepas de Saccharomyces spp seleccionadas con alta actividad hidroxicinamato descarboxilasa (HCDC) pueden acelerar la formación de aductos vinilfenólicos durante la fermentación. Estas levaduras descarboxilan los ácidos fenólicos formando vinilfenoles de elevada reactividad que espontáneamente condensan con antocianos de la uva formando una gran variedad de aductos vinilfenólicos dependiendo del tipo de antociano y del ácido hidroxicinámico precursor. Cuantitativamente los derivados más importantes son los del malvidin-3-O-glucosido. Adicionando ácidos hidroxicinámicos a las muestras se verifica que el aducto que se forma en mayor cantidad es el malvidin-3-O-glucosido-4-vinilguaiacol, siendo además el que produce mayor incremento de la intensidad colorante reduciendo a su vez las tonalidades amarillas en vinos. La utilización de cepas de Saccharomyces HCDC+ con o sin adiciones de ácidos hidroxicinámicos, puede constituirse en una interesante herramienta para mejorar el color de vinos tintos