El valor de uso recreativo del Parque Natural de L'Albufera a través del método indirecto del coste de viaje

La valoración económica de bienes que carecen de mercado, como son los espacios naturales protegidos, proporcionan una valiosa información que puede ser utilizada en el análisis coste-beneficio como fundamento de las decisiones públicas que afectan a la calidad del medio ambiente. En este trabajo se aplica el método indirecto del coste de viaje individual para obtener el valor de uso recreativo de un parque natural. Los resultados obtenidos se basan en una encuesta realizada en 1995 a 501 usuarios del parque y muestran como el excedente del consumidor obtenido es muy sensible a los criterios metodológicos adoptados en la especificación de la función de demanda. Además, ésta ha sido estimada por máxima verosimilitud para evitar estimaciones sesgadas del excedente del consumidor.The economic valuation of non-market goods, among which we can include protected natural areas, allows us to obtain valuable information that can be used in a cost-benefit framework as a base for public choice decisions affecting environmental quality. In the present study we apply an indirect valuation method, the travel cost method, to estimate the recreational use value of the Parque Natural de l’Albufera (Valencia). The results are based on a survey carried out in 1995 to 501 park visitors and show that the estimated consumer surplus is very sensitive to the methodological criteria adopted when specifying the demand function.gestión de espacios naturalescoste del viajevalor de uso y estimación por máxima verosimilitudIn pres

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