The Circumstellar Environment of High Mass Protostellar Objects. III Evidence of Infall?

The results are presented of a molecular line survey to search for the spectral signature of infall towards 77 850 micron continuum sources believed to be candidate high mass protostellar objects. Up to six different transitions, HCO+ 1-0, 3-2 and 4-3, H2CO 2_12-1_11, N2H+ and H13CO+ 3-2, were observed towards each source. Towards the peak of the 850 micron emission, N2H+ was typically strong, with a peak antenna temperature of ~1.5K, with a typical linewidth of ~2km/s. The good agreement between the velocity and velocity width of the N2H+ and H13CO+ emission suggests that both species are tracing similar material in the sources. With respect to the velocity of the N2H+, there is a statistically significant excess of blue asymmetric line profiles in both the HCO+ 1-0 and H2CO transitions. This excess reaches levels similar to that seen towards samples of low mass protostars, and suggests that the material around these high mass sources is infalling. We identify 22 promising candidate infall sources which show at least one blue asymmetric line profile and no red asymmetric profiles. The infall velocity is estimated to be in the range of 0.1 km/s to 1 km/s with an implied mass accretion rate of between 2x10^{-4} Msol/yr and 10^{-3}Msol/yr.Comment: Accepted for publication in Astronomy and Astrophysics. Higher resolution versions of Figures 1 and 2 are available from http://www.jb.man.ac.uk/~gaf/Papers.htm

Dichotomy in the Dynamical Status of Massive Cores in Orion

To study the evolution of high mass cores, we have searched for evidence of collapse motions in a large sample of starless cores in the Orion molecular cloud. We used the Caltech Submillimeter Observatory telescope to obtain spectra of the optically thin (\H13CO+) and optically thick (\HCO+) high density tracer molecules in 27 cores with masses $>$ 1 \Ms. The red- and blue-asymmetries seen in the line profiles of the optically thick line with respect to the optically thin line indicate that 2/3 of these cores are not static. We detect evidence for infall (inward motions) in 9 cores and outward motions for 10 cores, suggesting a dichotomy in the kinematic state of the non-static cores in this sample. Our results provide an important observational constraint on the fraction of collapsing (inward motions) versus non-collapsing (re-expanding) cores for comparison with model simulations.Comment: 9 pages, 2 Figures. To appear in ApJ(Letters

Test-meal palatability is associated with overconsumption but better represents preceding changes in appetite in non-obese males

Single course ad libitum meals are recommended for the assessment of energy intake within appetite research. This represents the first investigation of the comparative sensitivity of two single course ad libitum meals designed to differ in palatability. Two experiments were completed using a preload study design. All protocols were identical except for the energy content of the preloads (Experiment one: 579kJ and 1776kJ; Experiment two: 828kJ and 4188kJ). During each experiment, 10 healthy men completed four experimental trials constituting a low or high energy preload beverage, a 60 min intermeal interval, and consumption of a pasta-based or porridge-based ad libitum meal. Appetite ratings were measured throughout each trial and palatability was assessed after food consumption. Preload manipulation did not influence appetite (P=0.791) or energy intake (P=0.561) in experiment one. Palatability and energy intake were higher for the pasta meal than the porridge meal in both experiments (palatability P≤0.002; energy intake P≤0.001). In experiment two, consumption of the high energy preload decreased appetite (P=0.051) and energy intake (P=0.002). Energy compensation was not significantly different between pasta and porridge meals (P=0.172) but was more strongly correlated with preceding changes in appetite at the pasta meal (r=-0.758; P=0.011) than the porridge meal (r=-0.498; P=0.143). The provision of a highly palatable pasta-based meal produced energy intakes that were more representative of preceding appetite ratings but the moderately palatable porridge-based meal produced more ecologically valid energy intakes. Ad libitum meal selection and design may require a compromise between sensitivity and ecological validity

Bright single-photon sources in bottom-up tailored nanowires

The ability to achieve near-unity light extraction efficiency is necessary for a truly deterministic single photon source. The most promising method to reach such high efficiencies is based on embedding single photon emitters in tapered photonic waveguides defined by top-down etching techniques. However, light extraction efficiencies in current top-down approaches are limited by fabrication imperfections and etching induced defects. The efficiency is further tempered by randomly positioned off-axis quantum emitters. Here, we present perfectly positioned single quantum dots on the axis of a tailored nanowire waveguide using bottom-up growth. In comparison to quantum dots in nanowires without waveguide, we demonstrate a 24-fold enhancement in the single photon flux, corresponding to a light extraction efficiency of 42 %. Such high efficiencies in one-dimensional nanowires are promising to transfer quantum information over large distances between remote stationary qubits using flying qubits within the same nanowire p-n junction.Comment: 19 pages, 6 figure

Kinect Depth Sensor Evaluation for Computer Vision Applications

This technical report describes our evaluation of the Kinect depth sensor by Microsoft for Computer Vision applications. The depth sensor is able to return images like an ordinary camera, but instead of color, each pixel value represents the distance to the point. As such, the sensor can be seen as a range- or 3D-camera. We have used the sensor in several different computer vision projects and this document collects our experiences with the sensor. We are only focusing on the depth sensing capabilities of the sensor since this is the real novelty of the product in relation to computer vision. The basic technique of the depth sensor is to emit an infrared light pattern (with an IR laser diode) and calculate depth from the reflection of the light at different positions (using a traditional IR sensitive camera). In this report, we perform an extensive evaluation of the depth sensor and investigate issues such as 3D resolution and precision, structural noise, multi-cam setups and transient response of the sensor. The purpose is to give the reader a well-founded background to choose whether or not the Kinect sensor is applicable to a specific problem

The development of the largest colony of the Great Cormorant (Phalacrocorax carbo sinensis) in Europe

В данной статье представлена информация о самой крупной колонии древесного типа большого баклана (Phalacrocorax carbo sinensis) в Европе (14200 гнездящихся пар), сформировавшейся за последнеедесятилетие в Крыму (на Керченском п-ове). До недавнего времени самой большой вЕвропе гнездовой колонией Ph.c.sinensis древесного типа была колония Конты Рыбацкие(Северная Польша), насчитывавшая около 11 637 пар (Buczma et al., 2007). По мнению авторов, возникновение и развитие рассматриваемой колонии является примером экологической пластичности вида в условиях трансформации окружающей среды и деятельности человека