26 research outputs found
Multi-messenger observations of a binary neutron star merger
On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta
La mala calidad de sueño se asocia a una menor adherencia al tratamiento antirretroviral de gran actividad en pacientes peruanos con infección por VIH/SIDA
EDUCACIÓN AMBIENTAL Y SOCIEDAD. SABERES LOCALES PARA EL DESARROLLO Y LA SUSTENTABILIDAD
Este texto contribuye al análisis científico de varias áreas del conocimiento como la filosofía social, la patología, la educación para el cuidado del medio ambiente y la sustentabilidad que inciden en diversas unidades de aprendizaje de la Licenciatura en Educación para la Salud y de la Maestría en Sociología de la SaludLas comunidades indígenas de la sierra norte de Oaxaca México, habitan un territorio extenso de biodiversidad. Sin que sea una área protegida y sustentable, la propia naturaleza de la región ofrece a sus visitantes la riqueza de la vegetación caracterizada por sus especies endémicas que componen un paisaje de suma belleza
SLEUTH: Sustainable lifestyles - educating universities towards happiness
SLEUTH is an initiative born out of the need to bring universities towards more happy and sustainable lifestyles. It is the \u91real life\u92 application of the resulting conceptual design from the main study of the "Design for Happiness" PhD research project. This aims to identify and propose the design characteristics which compose a product, service or system capable of contributing to our happiness hence promoting sustainable lifestyles as part of mainstream sustainable design. The paper presents the SLEUTH project; its building process, implementation and results. The building process describes six months work which developed a key team within the university that started out on a \u91collaboration\u92 journey; they joined forces with the aim of developing and endorsing this initiative. It sets an example of the involvement required by an entire organization. The implementation process describes the actual trials of the SLEUTH project. Here, student involvement is crucial. SLEUTH has at its core the belief in collective action, and therefore it starts from the premise of giving ownership to its participants, allowing them to shape its course. This translates into making the students \u91coresponsible\u92 for the success of the project. Finally, the data and experiences gathered during the project illustrate the results of such an initiative. These aim to contribute to finding and setting the path for universities to embed sustainability at their core; they begin to answer questions such as how to achieve a transition towards sustainable universities; how to implement, replicate, modify, initiatives such as SLEUTH in the longer term
Livelihood-Environment Tensions, Agro-extractivism and Pastoralism: campesino farmers of the Boyacá páramos:Session: Beyond the Borderlands – exploring sustainable rural futures
Agropastoralism and Re-peasantisation: The Importance of Mobility and Social Networks in the páramos of Boyacá, Colombia
Applying the lens of sensory ethnography to sustainable HCI
Sociological appropriations of practice theory as applied to sustainable design have successfully problematized overly simplistic and individualistic models of consumer choice and behavior change. By taking everyday practices as the principal units of analysis, they move towards acknowledging the socially and materially structured nature of human activity. However, to inform sustainable HCI we also need to understand how practices are part of wider experiential environments and flows of practical activity. In this article, we develop an approach rooted in phenomenological anthropology and sensory ethnography. This approach builds on theories of place, perception and movement and enables us to situate practices, and understand practical activity, as emplaced within complex and shifting ecologies of things. Drawing on an interdisciplinary study of domestic energy consumption and digital media use, we discuss ethnographic and design practice examples. We demonstrate how this theoretical and methodological framework can be aligned with the 3rd paradigm of HCI
Importance of the spectral emissivity measurements at working temperature to determine the efficiency of a solar selective coating
The total emissivity of the absorbing surfaces is a critical parameter in the calculation of the radiative thermal losses in solar thermal collectors. This is because the radiative heat losses have a significant economic impact on the final cost of the electricity produced in a solar thermal plant. This paper
demonstrates the need to calculate the total emissivity from spectral emissivity measurements at the working temperature of the solar thermal collector, instead of using extrapolated values from spectral emissivities measured at room temperature. Usual uncertainties produced by the estimation of the total emissivity, in which its temperature dependence is only introduced by the Planck function, are analyzed
Importance of the spectral emissivity measurements at working temperature to determine the efficiency of a solar selective coating
The total emissivity of the absorbing surfaces is a critical parameter in the calculation of the radiative thermal losses in solar thermal collectors. This is because the radiative heat losses have a significant economic impact on the final cost of the electricity produced in a solar thermal plant. This paper demonstrates the need to calculate the total emissivity from spectral emissivity measurements at the working temperature of the solar thermal collector, instead of using extrapolated values from spectral emissivities measured at room temperature. Usual uncertainties produced by the estimation of the total emissivity, in which its temperature dependence is only introduced by the Planck function, are analyzed.This work has been carried out with the financial support of the ETORTEK and SAIOTEK 2013 program (Project numbers S-PC08UN07 and S-PE13UN123 respectively) of the Basque Government in collaboration with CIC-Energigune. T. Echániz acknowledges the Basque Government their support through a Ph.D. fellowship