Ejecta Evolution Following a Planned Impact into an Asteroid: The First Five Weeks

The impact of the DART spacecraft into Dimorphos, moon of the asteroid Didymos, changed Dimorphos' orbit substantially, largely from the ejection of material. We present results from twelve Earth-based facilities involved in a world-wide campaign to monitor the brightness and morphology of the ejecta in the first 35 days after impact. After an initial brightening of ~1.4 magnitudes, we find consistent dimming rates of 0.11-0.12 magnitudes/day in the first week, and 0.08-0.09 magnitudes/day over the entire study period. The system returned to its pre-impact brightness 24.3-25.3 days after impact through the primary ejecta tail remained. The dimming paused briefly eight days after impact, near in time to the appearance of the second tail. This was likely due to a secondary release of material after re-impact of a boulder released in the initial impact, through movement of the primary ejecta through the aperture likely played a role.Comment: 16 pages, 5 Figures, accepted in the Astrophysical Journal Letters (ApJL) on October 16, 202

Ejecta Evolution Following a Planned Impact into an Asteroid: The First Five Weeks

The impact of the Double Asteroid Redirection Test spacecraft into Dimorphos, moon of the asteroid Didymos, changed Dimorphos’s orbit substantially, largely from the ejection of material. We present results from 12 Earth-based facilities involved in a world-wide campaign to monitor the brightness and morphology of the ejecta in the first 35 days after impact. After an initial brightening of ∼1.4 mag, we find consistent dimming rates of 0.11–0.12 mag day−1 in the first week, and 0.08–0.09 mag day−1 over the entire study period. The system returned to its pre-impact brightness 24.3–25.3 days after impact though the primary ejecta tail remained. The dimming paused briefly eight days after impact, near in time to the appearance of the second tail. This was likely due to a secondary release of material after re-impact of a boulder released in the initial impact, though movement of the primary ejecta through the aperture likely played a role

Spawning behavior of the tiger grouper (Mycteroperca tigris) in a Caribbean atoll

Este artículo contiene 15 páginas, 8 figuras, 4 tablas.Many grouper (Epinephelidae) species aggregate to spawn at specific times of year, at consistent locations, and at specific times of day and phases of the moon. The tiger grouper (Mycteroperca tigris) iswidely distributed in the Caribbean Sea and aggregates to spawn just after the full moon. In January and February 2003–2005, we conducted visual surveys of a tiger grouper spawning aggregation at Glover’s Reef, Belize. The primary objectives of this study were to describe grouper spawning activities with respect to the timing of the lunar cycle, identify and describe male and female spawning behaviors, and estimate the number of grouper spawning events each day. The peak number of both male and female tiger groupers counted each year occurred from 6 to 10 d after the fullmoon. The peak count of males was 1.6–2.2 times greater than the peak count of females. Six categories of male–male and six categories of male–female interactions were identified. All male tiger groupers displayed an ability to rapidly change color; this was often triggered by a close encounter with other male or female tiger groupers. The daily spawning activity was remarkably predictable. The first spawning occurred on average 8.1 min before sunset, and the last occurred 5.1 min after sunset. On average, less than half of the females at the spawning site spawned each day, but some females spawned more than once in a given day. Females appeared to choose their mates.Peer reviewe

Simposi sobre Tribunals i Mediació : nous camins per a la Justicia : comunicacions : 18-19 de juny/junio de 2009 CosmoCaixa, Barcelona, España

Aquest volum conté les Comunicacions presentades al Simposi sobre Tribunals i Mediació celebrat a Barcelona els dies 18 i 19 de Juny del 2009. Però, en realitat, aquests treballs són en la seva gran majoria contribucions al Projecte de Llibre Blanc de la mediació a Catalunya. Es per aquesta raó que hem optat per efectuar-ne una edició no intrusiva, on cada autor aporta el seu gra de sorra lliurement des de la perspectiva que ha triat. El lector trobarà sens dubte una gran varietat d'apropaments al tema: hi ha reflexions conceptuals, estudis jurídics, experiències de implantació ciutadana, reflexions dels equips tècnics de professionals, experiències de psicòlegs, juristes, advocats i magistrats, i, fins i tot, treballs preliminars. Hi ha escrits de recerca d'una gran qualitat; d'altres, en canvi, són una aportació d'autors més primerencs.El presente volumen comprende las Comunicaciones presentadas en el Simposio sobre Tribunales y Mediación celebrado en Barcelona durante los días 18 y 19 de Junio de 2009. Pero, en realidad, estos trabajos son en su gran mayoría contribuciones al Proyecto de Libro Blanco de la mediación en Cataluña. Por esta razón, hemos optado por efectuar una edición no intrusiva, en la que cada autor aporta libremente su grano de arena desde la perspectiva que le es propia. El lector encontrará sin duda una gran variedad de aproximaciones al tema: hay reflexiones conceptuales, estudios jurídicos, experiencias de implantación ciudadana, reflexiones de los equipos técnicos de profesionales, experiencias de psicólogos, juristas, abogados y magistrados, y trabajos aún muy preliminares. Algunas comunicaciones poseen una gran calidad investigadora; otros, en cambio, constituyen la primera apor- tación al tema de su autor

Ejecta Evolution Following a Planned Impact into an Asteroid:The First Five Weeks

The impact of the DART spacecraft into Dimorphos, moon of the asteroid Didymos, changed Dimorphos' orbit substantially, largely from the ejection of material. We present results from twelve Earth-based facilities involved in a world-wide campaign to monitor the brightness and morphology of the ejecta in the first 35 days after impact. After an initial brightening of ~1.4 magnitudes, we find consistent dimming rates of 0.11-0.12 magnitudes/day in the first week, and 0.08-0.09 magnitudes/day over the entire study period. The system returned to its pre-impact brightness 24.3-25.3 days after impact through the primary ejecta tail remained. The dimming paused briefly eight days after impact, near in time to the appearance of the second tail. This was likely due to a secondary release of material after re-impact of a boulder released in the initial impact, through movement of the primary ejecta through the aperture likely played a role