Multiwavelength interferometric observations and modeling of circumstellar disks

We investigate the structure of the innermost region of three circumstellar disks around pre-main sequence stars HD 142666, AS 205 N, and AS 205 S. We determine the inner radii of the dust disks and, in particular, search for transition objects where dust has been depleted and inner disk gaps have formed at radii of a few tenths of AU up to several AU. We performed interferometric observations with IOTA, AMBER, and MIDI in the infrared wavelength ranges 1.6-2.5um and 8-13um with projected baseline lengths between 25m and 102m. The data analysis was based on radiative transfer simulations in 3D models of young stellar objects (YSOs) to reproduce the spectral energy distribution and the interferometric visibilities simultaneously. Accretion effects and disk gaps could be considered in the modeling approach. Results from previous studies restricted the parameter space. The objects of this study were spatially resolved in the infrared wavelength range using the interferometers. Based on these observations, a disk gap could be found for the source HD 142666 that classifies it as transition object. There is a disk hole up to a radius of R_in=0.30AU and a (dust-free) ring between 0.35AU and 0.80AU in the disk of HD 142666. The classification of AS 205 as a system of classical T Tauri stars could be confirmed using the canonical model approach, i. e., there are no hints of disk gaps in our observations.Comment: accepted by Astronomy & Astrophysic

Sedigism: Structure, Excitation, And Dynamics Of The Inner Galactic Interstellar Medium

The origin and life-cycle of molecular clouds are still poorly constrained, despite their importance for understanding the evolution of the interstellar medium. Many large-scale surveys of the Galactic plane have been conducted recently, allowing for rapid progress in this field. Nevertheless, a sub-arcminute resolution global view of the large-scale distribution of molecular gas, from the diffuse medium to dense clouds and clumps, and of their relationshipto the spiral structure, is still missing

ATLASGAL - environments of 6.7 GHz methanol masers

Using the 870 micron APEX Telescope large area survey of the Galaxy, we have identified 577 submillimetre continuum sources with masers from the methanol multibeam survey in the region 280deg lt ell lt 20deg; |b| lt 1deg.5 94 per cent of methanol masers in the region are associated with submillimetre dust emission. We estimate masses for tilde450 maser-associated sources and find that methanol masers are preferentially associated with massive clumps. These clumps are centrally condensed, with envelope structures that appear to be scale-free, the mean maser position being offset from the peak column density by 0 plusmn 4 arcsec. Assuming a Kroupa initial mass function and a star formation efficiency of tilde30 per cent, we find that over two-thirds of the clumps are likely to form clusters with masses gt20 M$_?$. Furthermore, almost all clumps satisfy the empirical mass-size criterion for massive star formation. Bolometric luminosities taken from the literature for tilde100 clumps range between tilde100 and 10$^6$ L$_?$. This confirms the link between methanol masers and massive young stars for 90 per cent of our sample. The Galactic distribution of sources suggests that the star formation efficiency is significantly reduced in the Galactic Centre region, compared to the rest of the survey area, where it is broadly constant, and shows a significant drop in the massive star formation rate density in the outer Galaxy. We find no enhancement in source counts towards the southern Scutum-Centaurus arm tangent at ell tilde 315deg, which suggests that this arm is not actively forming stars.Peer reviewe

ATLASGAL - towards a complete sample of massive star forming clumps

By matching infrared-selected, massive young stellar objects (MYSOs) and compact HII regions in the Red MSX Source survey to massive clumps found in the submillimetre ATLASGAL (APEX Telescope Large Area Survey of the Galaxy) survey, we have identified ~1000 embedded young massive stars between 280{ring operator} <lPeer reviewedFinal Accepted Versio

Innovative Schematic Concept Analysis for a Space Suit Portable Life Support Subsystem

Conceptual designs for a space suit Personal Life Support Subsystem (PLSS) were developed and assessed to determine if upgrading the system using new, emerging, or projected technologies to fulfill basic functions would result in mass, volume, or performance improvements. Technologies were identified to satisfy each of the functions of the PLSS in three environments (zero-g, Lunar, and Martian) and in three time frames (2006, 2010, and 2020). The viability of candidate technologies was evaluated using evaluation criteria such as safety, technology readiness, and reliability. System concepts (schematics) were developed for combinations of time frame and environment by assigning specific technologies to each of four key functions of the PLSS -- oxygen supply, waste removal, thermal control, and power. The PLSS concepts were evaluated using the ExtraVehicular Activity System Sizing Analysis Tool, software created by NASA to analyze integrated system mass, volume, power and thermal loads. The assessment resulted in the Texas Engineering Experiment Station recommending to NASA an evolution path from the existing PLSS to a long duration, low mass PLSS suitable for Martian missions

Populational analysis of Saccharomyces cerevisiae strains from different appellations of origin and grape varieties by microsatellite analysis.

The objective of the present study was to evaluate populational relationships among Saccharomyces cerevisiae strains isolated from some of the Portuguese most important grapevine varieties in different appellations of origin, using polymorphic microsatellites. &#xd;&#xa;One hundred ninety two grape samples were collected during the 2006 and 2007 harvest season in the Vinho Verde (grape varieties: Arinto, Alvarinho, Avesso, Loureiro, Touriga Nacional) Bairrada (grape varieties: Arinto, Baga, Castel&#xe3;o Franc&#xea;s, Maria Gomes, Touriga Nacional) Alentejo (grape varieties, Aragon&#xea;s, Trincadeira, Touriga Nacional), Terras do Sado (grape variety Castel&#xe3;o) Bucelas (grape variety Arinto) and Estremadura (grape varieties: Arinto, Aragon&#xea;s, Castel&#xe3;o, Trincadeira, Touriga Nacional) appellations of origin. From the final stage of spontaneous fermentations, 2820 yeast isolates were obtained, mainly belonging to the species S. cerevisiae. An initial genetic screen, based on mitochondrial DNA restriction fragment length polymorphism (mtDNA RFLP) and/or interdelta sequence analysis was followed by microsatellite analysis of strains with unique genetic profiles, using 10 highly polymorphic microsatellites. Our results showed that microsatellite analysis revealed a high resolution populational screen, showing that genetic differences and populational structures among S. cerevisiae populations derived from both &#x201c;diagnostic&#x201d; vineyard-, specific alleles and the accumulation of small allele-frequency differences across ten microsatellite loci. Heterozygosity was three to four times lower than the expected value, confirming the strong populational substructuring. The presented large-scale approach shows that each vineyard contains differentiated S. cerevisiae populations, showing the occurrence of specific native strains that can be associated with a terroir. &#xd;&#xa;&#xd;&#xa;Financially supported by the programs POCI 2010 (FEDER/FCT, POCTI/AGR/56102/2004) and AGRO (ENOSAFE, N&#xba; 762).&#xd;&#xa

Speaker-independent emotion recognition exploiting a psychologically-inspired binary cascade classification schema

In this paper, a psychologically-inspired binary cascade classification schema is proposed for speech emotion recognition. Performance is enhanced because commonly confused pairs of emotions are distinguishable from one another. Extracted features are related to statistics of pitch, formants, and energy contours, as well as spectrum, cepstrum, perceptual and temporal features, autocorrelation, MPEG-7 descriptors, Fujisakis model parameters, voice quality, jitter, and shimmer. Selected features are fed as input to K nearest neighborhood classifier and to support vector machines. Two kernels are tested for the latter: Linear and Gaussian radial basis function. The recently proposed speaker-independent experimental protocol is tested on the Berlin emotional speech database for each gender separately. The best emotion recognition accuracy, achieved by support vector machines with linear kernel, equals 87.7%, outperforming state-of-the-art approaches. Statistical analysis is first carried out with respect to the classifiers error rates and then to evaluate the information expressed by the classifiers confusion matrices. © Springer Science+Business Media, LLC 2011

Differentiation of \u3ci\u3eMannheimia haemolytica\u3c/i\u3e genotype 1 and 2 strains by visible phenotypic characteristics on solid media

Genotype 2 Mannheimia haemolytica associate with the lungs of cattle with bovine respiratory disease more frequently than genotype 1 strains. Different colony colors and morphologies were identified between genotype 1 and 2 solid media cultures. Genotype of strains, and frequency differences between them in mixed cultures are discernable by visual inspection. Supplements attache

Dip coating process: Silicon sheet growth development for the large-area silicon sheet task of the low-cost silicon solar array project

The technical and economic feasibility of producing solar cell quality sheet silicon by dip-coating one surface of carbonized ceramic substrates with a thin layer of large grain polycrystalline silicon was investigated. The dip-coating methods studied were directed toward a minimum cost process with the ultimate objective of producing solar cells with a conversion efficiency of 10% or greater. The technique shows excellent promise for low cost, labor-saving, scale-up potentialities and would provide an end product of sheet silicon with a rigid and strong supportive backing. An experimental dip-coating facility was designed and constructed, several substrates were successfully dip-coated with areas as large as 25 sq cm and thicknesses of 12 micron to 250 micron. There appears to be no serious limitation on the area of a substrate that could be coated. Of the various substrate materials dip-coated, mullite appears to best satisfy the requirement of the program. An inexpensive process was developed for producing mullite in the desired geometry

Star formation triggered by HII regions in our Galaxy: First results for N49 from the Herschel infrared survey of the Galactic plane

It has been shown that by means of different physical mechanisms the expansion of HII regions can trigger the formation of new stars of all masses. This process may be important to the formation of massive stars but has never been quantified in the Galaxy. We use Herschel-PACS and -SPIRE images from the Herschel Infrared survey of the Galactic plane, Hi-GAL, to perform this study. We combine the Spitzer-GLIMPSE and -MIPSGAL, radio-continuum and sub-millimeter surveys such as ATLASGAL with Hi-GAL to study Young Stellar Objects (YSOs) observed towards Galactic HII regions. We select a representative HII region, N49, located in the field centered on l=30 degr observed as part of the Hi-GAL Science Demonstration Phase, to demonstrate the importance Hi-GAL will have to this field of research. Hi-GAL PACS and SPIRE images reveal a new population of embedded young stars, coincident with bright ATLASGAL condensations. The Hi-GAL images also allow us, for the first time, to constrain the physical properties of the newly formed stars by means of fits to their spectral energy distribution. Massive young stellar objects are observed at the borders of the N49 region and represent second generation massive stars whose formation has been triggered by the expansion of the ionized region. Hi-GAL enables us to detect a population of young stars at different evolutionary stages, cold condensations only being detected in the SPIRE wavelength range. The far IR coverage of Hi-GAL strongly constrains the physical properties of the YSOs. The large and unbiased spatial coverage of this survey offers us a unique opportunity to lead, for the first time, a global study of star formation triggered by HII regions in our Galaxy.Comment: 4 pages, 2 figures, accepted by A&A (Special issue on Herschel first results