Observations of T Tauri Disks at Sub-AU Radii: Implications for Magnetospheric Accretion and Planet Formation

We determine inner disk sizes and temperatures for four solar-type (1-2 M$_{\odot}$) classical T Tauri stars (AS 207A, V2508 Oph, AS 205A, and PX Vul) using 2.2 $\mu$m observations from the Keck Interferometer. Nearly contemporaneous near-IR adaptive optics imaging photometry, optical photometry, and high-dispersion optical spectroscopy are used to distinguish contributions from the inner disks and central stars in the interferometric observations. In addition, the spectroscopic and photometric data provide estimates of stellar properties, mass accretion rates, and disk co-rotation radii. We model our interferometric and photometric data in the context of geometrically flat accretion disk models with inner holes, and flared disks with puffed-up inner walls. Models incorporating puffed-up inner disk walls generally provide better fits to the data, similar to previous results for higher-mass Herbig Ae stars. Our measured inner disk sizes are larger than disk truncation radii predicted by magnetospheric accretion models, with larger discrepancies for sources with higher mass accretion rates. We suggest that our measured sizes correspond to dust sublimation radii, and that optically-thin gaseous material may extend further inward to the magnetospheric truncation radii. Finally, our inner disk measurements constrain the location of terrestrial planet formation as well as potential mechanisms for halting giant planet migration.Comment: Accepted for publication in ApJ (May 1, 2005 issue

Invasion and eradication of the American mink in the Atlantic Islands National Park (NW Spain) a retrospective analysis

Alien predators exert severe effects on island ecosystems, and their eradication from island habitats may therefore be necessary to conserve the native biota. Efforts are being made to eradicate the American mink (Neovison vison) from the Atlantic Islands of Galicia National Park (NW Spain), a protected site inhabited by vulnerable island fauna. We applied a molecular genetic approach to elucidate the source of the invaders and to evaluate the effectiveness of the trapping programme. We collected mink scats in the field and obtained tissue samples from culled mink. Populations of feral mink were known to be present in coastal areas close to the National Park archipelagos in the 1980–1990s. However, the molecular findings suggest that these populations were not the main source of the mink populations that colonized the islands during the 2000s. Recent releases from farms directly on to the islands are a more likely source of these invaders. Genetic analysis suggested that mink reproduced successfully on the islands and were relatively isolated from other mainland populations. The findings also suggest that most of the culled mink were juveniles, probably because it was more difficult to catch adults. Since mink are short-lived animals, it seems that eradication may also be achieved when a large proportion of juveniles are culled in isolated and small populations. © 2016, Springer International Publishing Switzerland

EXTRUSIÓN. UNA ALTERNATIVA DE TRATAMIENTO DE LA FRACTURA CORONO-RADICULAR

Fil: Fernández Alemán, J. E. Universidad de Buenos Aires. Facultad de Odontología; Argentina.Fil: Chaintiou Piorno, R. Universidad de Buenos Aires. Facultad de Odontología; Argentina.Fil: Vázquez Magni, M. P. Universidad de Buenos Aires. Facultad de Odontología; Argentina.Fil: Lenarduzzi, A. Universidad de Buenos Aires. Facultad de Odontología; Argentina.Fil: Rodríguez, P. A. Universidad de Buenos Aires. Facultad de Odontología; Argentina.La extrusión dentaria o erupción forzada es una op-ción de tratamiento con enormes ventajas cuando nos vemos obligados a tratar fracturas corono-radicula-res.Se define como el movimiento en dirección coronal a través de la aplicación de fuerzas ligeras y continuas para provocar cambios en los tejidos blandos y hueso.La extrusión dental forzada amplía las alternativas en cuanto a la rehabilitación futura del paciente, ya que se puede optar por la restauración periférica to-tal con anclaje del resto radicular, o bien por la exo-doncia posterior a la extrusión, con la consecuente mejoría de las condiciones del tejido óseo para una posterior rehabilitación implanto-asistida

Getting more out of energy-harvesting systems: energy management under time-varying utility with PreAct

Careful energy management is a prerequisite for long-term, unattended operation of solar-harvesting sensing systems. We observe that in many applications the utility of sensed data varies over time, but current energy-management algorithms do not exploit prior knowledge of these variations for making better decisions. This paper presents PreAct, the first energy-management algorithm that exploits time-varying utility to optimize application performance. PreAct's design combines strategic long-term planning of future energy utilization with feedback control to compensate for deviations from the expected conditions. We implement PreAct on a low-power microcontroller and compare it against the state of the art on multiple years of real-world data. Our results demonstrate that PreAct is up to 53 % more effective in utilizing harvested solar energy and significantly more robust to uncertainties and inefficiencies of practical systems. These gains translate into an improvement of 28% in the end-to-end performance of a real-world application we investigate when using PreAct