858 research outputs found
Evaluating Ground Truth for ADRess as a Preprocess for Automatic Musical Instrument Identification
Most research in musical instrument identification has focused on labeling isolated samples or solo phrases. A robust instrument identification system capable of dealing with polytimbral recordings of instruments remains a necessity in music information retrieval. Experiments are described which evaluate the ground truth of ADRess as a sound source separation technique used as a preprocess to automatic musical instrument identification. The ground truth experiments are based on a number of basic acoustic features, while using a Gaussian Mixture Model as the classification algorithm. Using all 44 acoustic feature dimensions, successful identification rates are achieved
Diet of Western Slimy Salamander, Plethodon albagula (Caudata: Plethodontidae), from Two Mountain Ranges in Arkansas
We identified stomach contents of 80 Plethodon albagula (Western Slimy Salamander) from two mountain ranges in Arkansas (Ozark and Ouachita) to examine if regional differences in diet occur. Museum specimens from 1985 to 2005 were used from locations throughout each mountain range. Although a wide variety of prey were found in stomachs, Hymenoptera: Formicidae and Coleoptera: Carabidae were found to be the most important food items in the diet of P. albagula. Ants and beetles constituted 85% abundance of their total diet (79.6% Ozark and 90.1% Ouachita) and 52.2% of their total biomass (42.6% Ozark and 64.1% Ouachita). Seventy-eight and 87% of individuals examined from the Ozark and Ouachita Mountains, respectively, consumed ants (65% total, 83% for animals with food items in their stomachs), whereas 55% in the Ozarks and 58% in the Ouachitas consumed at least one family of beetle. Occurrence and biomass of prey items that did not include ants and beetles showed P. albagula to be a euryphagic predator, with 9.7% of diet being comprised of other prey types (27.3% biomass). Furthermore, importance values indicate ants were the most important prey item for P. albagula in both the Ozark and Ouachita samples, with carabid beetles (Ozark) and all beetles (Ouachita) being second most important. Jaccard Index indicated Ozark and Ouachita specimens shared 80% similarity in diet. Our data suggest P. albagula in Arkansas have high dependence upon ants and beetles, yet appears to be an opportunistic and euryphagic predator
An engineering database management system for spacecraft operations
Studies at ESOC have demonstrated the feasibility of a flexible and powerful Engineering Database Management System in support for spacecraft operations documentation. The objectives set out were three-fold: first an analysis of the problems encountered by the Operations team in obtaining and managing operations documents; secondly, the definition of a concept for operations documentation and the implementation of prototype to prove the feasibility of the concept; and thirdly, definition of standards and protocols required for the exchange of data between the top-level partners in a satellite project. The EDMS prototype was populated with ERS-l satellite design data and has been used by the operations team at ESOC to gather operational experience. An operational EDMS would be implemented at the satellite prime contractor's site as a common database for all technical information surrounding a project and would be accessible by the cocontractor's and ESA teams
Minimal Unitary Realizations of Exceptional U-duality Groups and Their Subgroups as Quasiconformal Groups
We study the minimal unitary representations of noncompact exceptional groups
that arise as U-duality groups in extended supergravity theories. First we give
the unitary realizations of the exceptional group E_{8(-24)} in SU*(8) as well
as SU(6,2) covariant bases. E_{8(-24)} has E_7 X SU(2) as its maximal compact
subgroup and is the U-duality group of the exceptional supergravity theory in
d=3. For the corresponding U-duality group E_{8(8)} of the maximal supergravity
theory the minimal realization was given in hep-th/0109005. The minimal unitary
realizations of all the lower rank noncompact exceptional groups can be
obtained by truncation of those of E_{8(-24)} and E_{8(8)}. By further
truncation one can obtain the minimal unitary realizations of all the groups of
the "Magic Triangle". We give explicitly the minimal unitary realizations of
the exceptional subgroups of E_{8(-24)} as well as other physically interesting
subgroups. These minimal unitary realizations correspond, in general, to the
quantization of their geometric actions as quasi-conformal groups as defined in
hep-th/0008063.Comment: 28 pages. Latex commands removed from the abstract for the arXiv. No
changes in the manuscrip
Walruses Attack Spectacled Eiders Wintering in Pack Ice of the Bering Sea
We observed walruses (Odobenus rosmarus) pursuing spectacled eiders (Somateria fischeri) within pack ice of the Bering Sea, 70–90 km from the nearest land. We used both direct observations from a helicopter and a heligimbal camera system that can film animals from a helicopter at high altitudes. The eiders were in monospecific flocks of thousands of birds within large leads. The walruses apparently tried to catch the eiders from below; the eiders responded with a “flash expansion” (explosive radial movement), wing-flapping and running along the water surface to escape. Disturbance by individual walruses could restrict flocks of thousands of birds to small portions of the open water. In eight such events that we witnessed over 75 min of observations, we were unable to confirm that walruses captured any of these full-grown, flight-capable eiders. However, the high rate of attacks and the eiders’ dramatic escape response suggest that walruses can at times be effective predators on them, and may affect the eiders’ dispersion and energy balance.Nous avons observé des morses (Odobenus rosmarus) en train de pourchasser des eiders à lunettes (Somateria fischeri) sur la banquise de la mer de Béring, soit à une distance de 70 à 90 kilomètres de la terre ferme la plus près. Nous nous sommes servis à la fois d’observations directes faites à partir d’un hélicoptère et d’un appareil héligimbal capable de filmer les animaux à partir d’un hélicoptère à haute altitude. Les eiders se tenaient en bandes monospécifiques constituées de milliers d’oiseaux faisant partie de gros groupements. Il semblait que les morses essayaient d’attraper les eiders par en-dessous; les eiders réagissaient en faisant une « expansion éclair » (un mouvement radial explosif), en battant des ailes et en courant le long de la surface de l’eau afin de s’échapper. Les perturbations exercées par les morses individuels pouvaient avoir pour effet de restreindre les bandes de milliers d’oiseaux à de petites nappes d’eau libre. Dans huit cas de telle nature dont nous avons été témoins pendant plus de 75 minutes d’observation, nous n’avons pas été en mesure de confirmer si les morses avaient réussi à capturer des eiders adultes en état de voler. Cependant, le taux élevé d’attaques de même que la réaction dramatique des eiders qui tentaient de s’échapper laissent entrevoir que les morses pourraient être des prédateurs efficaces en ce qui les concerne, ce qui pourrait exercer une influence sur l’expansion des eiders et sur leur bilan énergétique
Chromatin profiling of Drosophila CNS subpopulations identifies active transcriptional enhancers
One of the key issues in studying transcriptional regulation during development is how to employ genome-wide assays that reveals sites of open chromatin and transcription factor binding to efficiently identify biologically relevant genes and enhancers. Analysis of Drosophila CNS midline cell development provides a useful system for studying transcriptional regulation at the genomic level due to a large, well-characterized set of midline-expressed genes and in vivo validated enhancers. In this study, FAIRE-seq on FACS-purified midline cells was performed and the midline FAIRE data were compared with whole-embryo FAIRE data. We find that regions of the genome with a strong midline FAIRE peak and weak whole-embryo FAIRE peak overlap with known midline enhancers and provide a useful predictive tool for enhancer identification. In a complementary analysis, we compared a large dataset of fragments that drive midline expression in vivo with the FAIRE data. Midline enhancer fragments with a midline FAIRE peak tend to be near midline-expressed genes, whereas midline enhancers without a midline FAIRE peak were often distant from midline-expressed genes and unlikely to drive midline transcription in vivo
Stria Vascularis Dysfunction in a Mouse Model of Mitochondrial Hearing Loss
We recently described a transgenic mouse model of hearing loss induced by over-expression of the mitochondrial ribosomal RNA (rRNA) methyltransferase, TFB1M (Tg-TFB1M). These mice recapitulate maternally inherited deafness caused by the human A1555G mtDNA mutation, which results in increased methylation of the 12S rRNA in mitochondrial ribosomes and tissue-specific susceptibility to apoptosis. The present study aims to identify the specific cellular and tissue based pathologies underlying this form of deafness
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