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Search Results: 1 - 10 of 219548 matches for " C. Bellas "
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A Novel Evolutionary Strategy Revealed in the Phaeoviruses
Kim Stevens, Karen Weynberg, Christopher Bellas, Sonja Brown, Colin Brownlee, Murray T. Brown, Declan C. Schroeder
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0086040
Abstract: Phaeoviruses infect the brown algae, which are major contributors to primary production of coastal waters and estuaries. They exploit a Persistent evolutionary strategy akin to a K- selected life strategy via genome integration and are the only known representatives to do so within the giant algal viruses that are typified by r- selected Acute lytic viruses. In screening the genomes of five species within the filamentous brown algal lineage, here we show an unprecedented diversity of viral gene sequence variants especially amongst the smaller phaeoviral genomes. Moreover, one variant shares features from both the two major sub-groups within the phaeoviruses. These phaeoviruses have exploited the reduction of their giant dsDNA genomes and accompanying loss of DNA proofreading capability, typical of an Acute life strategist, but uniquely retain a Persistent life strategy.
Evaluación y calidad de los servicios de información: una propuesta teórico-metodológica
Alarcón Echenique,Marlén; Cárdenas Yzquierdo,Loreto; Bellas Vilari?o,Margarita; Santiesteban Gómez,Isabel;
ACIMED , 2007,
Abstract: a group of theoretical and conceptual aspects related to evaluation and quality, is presented, as well as the relation between these two terms. the view and application of these elements in library activities is analyzed. a first theoretical-methodological approach towards the achievement of perfection is carried out.
Evaluación y calidad de los servicios de información: una propuesta teórico-metodológica Evaluation and quality of the information services: a theoretical and methodological proposal
Marlén Alarcón Echenique,Loreto Cárdenas Yzquierdo,Margarita Bellas Vilari?o,Isabel Santiesteban Gómez
ACIMED , 2007,
Abstract: Se presenta un conjunto de aspectos teórico-conceptuales relacionados con la evaluación y la calidad, así como la relación entre ambos términos. Se analizan la visión y la aplicación de estos elementos en la actividad bibliotecaria. Se realiza un primer acercamiento teórico-metodológico con vista a contribuir a su perfeccionamiento. A group of theoretical and conceptual aspects related to evaluation and quality, is presented, as well as the relation between these two terms. The view and application of these elements in library activities is analyzed. A first theoretical-methodological approach towards the achievement of perfection is carried out.
Microbial nitrogen cycling on the Greenland Ice Sheet
J. Telling, M. Stibal, A. M. Anesio, M. Tranter, I. Nias, J. Cook, C. Bellas, G. Lis, J. L. Wadham, A. Sole, P. Nienow,A. Hodson
Biogeosciences (BG) & Discussions (BGD) , 2012,
Abstract: Nitrogen inputs and microbial nitrogen cycling were investigated along a 79 km transect into the Greenland Ice Sheet (GrIS) during the main ablation season in summer 2010. The depletion of dissolved nitrate and production of ammonium (relative to icemelt) in cryoconite holes on Leverett Glacier, within 7.5 km of the ice sheet margin, suggested microbial uptake and ammonification respectively. Positive in situ acetylene assays indicated nitrogen fixation both in a debris-rich 100 m marginal zone and up to 5.7 km upslope on Leverett Glacier (with rates up to 16.3 μmoles C2H4 m 2 day 1). No positive acetylene assays were detected > 5.7 km into the ablation zone of the ice sheet. Potential nitrogen fixation only occurred when concentrations of dissolved and sediment-bound inorganic nitrogen were undetectable. Estimates of nitrogen fluxes onto the transect suggest that nitrogen fixation is likely of minor importance to the overall nitrogen budget of Leverett Glacier and of negligible importance to the nitrogen budget on the main ice sheet itself. Nitrogen fixation is however potentially important as a source of nitrogen to microbial communities in the debris-rich marginal zone close to the terminus of the glacier, where nitrogen fixation may aid the colonization of subglacial and moraine-derived debris.
A semi-empirical library of galaxy spectra for Gaia classification based on SDSS data and PEGASE models
P. Tsalmantza,A. Karampelas,M. Kontizas,C. A. L. Bailer-Jones,B. Rocca-Volmerange,E. Livanou,I. Bellas-Velidis,E. Kontizas,A. Vallenari
Physics , 2011, DOI: 10.1051/0004-6361/201117125
Abstract: Aims:This paper is the third in a series implementing a classification system for Gaia observations of unresolved galaxies. The system makes use of template galaxy spectra in order to determine spectral classes and estimate intrinsic astrophysical parameters. In previous work we used synthetic galaxy spectra produced by PEGASE.2 code to simulate Gaia observations and to test the performance of Support Vector Machine (SVM) classifiers and parametrizers. Here we produce a semi-empirical library of galaxy spectra by fitting SDSS spectra with the previously produced synthetic libraries. We present (1) the semi-empirical library of galaxy spectra, (2) a comparison between the observed and synthetic spectra, and (3) first results of claassification and parametrization experiments with simulated Gaia spectrophotometry of this library. Methods: We use chi2-fitting to fit SDSS galaxy spectra with the synthetic library in order to construct a semi-empirical library of galaxy spectra in which (1) the real spectra are extended by the synthetic ones in order to cover the full wavelength range of Gaia, and (2) astrophysical parameters are assigned to the SDSS spectra by the best fitting synthetic spectrum. The SVM models were trained with and applied to semi-empirical spectra. Tests were performed for the classification of spectral types and the estimation of the most significant galaxy parameters (in particular redshift, mass to light ratio and star formation history). Results: We produce a semi-empirical library of 33670 galaxy spectra covering the wavelength range 250 to 1050 nm at a sampling of 1 nm or less. Using the results of the fitting of the SDSS spectra with our synthetic library, we investigate the range of the input model parameters that produces spectra which are in good agreement with observations. (abridged)
Tumor intraabdominal desmoplásico de células peque?as y redondas: Revisión de la literatura a propósito de un caso con estudio citológico, histopatológico, inmunohistoquímico y molecular
Tejerina González,E.; Corbacho Cuevas,C.; López García,A.; Bellas Menéndez,C.; Sánchez Turrión,V.; Sánchez Ruiz,A.; álava,E. de; Sanz Ortega,E.;
Oncología (Barcelona) , 2007, DOI: 10.4321/S0378-48352007000100005
Abstract: purpose: to review the cyto-histopathological, immunohistochemical and molecular characteristics of small round cell desmoplastic tumor (dsrct). material and methods: a 18 year old male with an intraabdominal epigastric mass. results: the tumor consisted of nests and masses of undifferentiated small round cells embedded in a desmoplastic stroma, with areas of rosette formation immuno-reactive to cytokeratins, vimentin, desmin, enolase, and wt1 fraction of the ews/wt1 fusion protein transcript. the molecular study demonstrated the existence of the translocation t(11;22)(p13;q12). conclusions: the solid areas and rosette formation have been described in other cases of dsrct. the chimeric transcription product can be detected by rt-pcr, southern-blot, western-blot, and immunohistochemistry. cytology is especially useful in recurrences. the differential diagnosis should be made with the small round undifferented cell tumors group.
Towards a library of synthetic galaxy spectra and preliminary results of classification and parametrization of unresolved galaxies for Gaia - II
P. Tsalmantza,M. Kontizas,B. Rocca-Volmerange,C. A. L. Bailer-Jones,E. Kontizas,I. Bellas-Velidis,E. Livanou,R. Korakitis,A. Dapergolas,A. Vallenari,M. Fioc
Physics , 2009, DOI: 10.1051/0004-6361/200912014
Abstract: This paper is the second in a series, implementing a classification system for Gaia observations of unresolved galaxies. Our goals are to determine spectral classes and estimate intrinsic astrophysical parameters via synthetic templates. Here we describe (1) a new extended library of synthetic galaxy spectra, (2) its comparison with various observations, and (3) first results of classification and parametrization experiments using simulated Gaia spectrophotometry of this library. Using the PEGASE.2 code, based on galaxy evolution models that take account of metallicity evolution, extinction correction, and emission lines (with stellar spectra based on the BaSeL library), we improved our first library and extended it to cover the domain of most of the SDSS catalogue. We produce an extended library of 28885 synthetic galaxy spectra at zero redshift covering four general Hubble types of galaxies, over the wavelength range between 250 and 1050 nm at a sampling of 1 nm or less. The library is also produced for 4 random values of redshift in the range of 0-0.2. It is computed on a random grid of four key astrophysical parameters (infall timescale and 3 parameters defining the SFR) and, depending on the galaxy type, on two values of the age of the galaxy. The synthetic library was compared and found to be in good agreement with various observations. The first results from the SVM classifiers and parametrizers are promising, indicating that Hubble types can be reliably predicted and several parameters estimated with low bias and variance.
Rese a de "Atleta, substantivo feminino: As mulheres brasileiras nos jogos olímpicos" de Oscar Valporto
Sandra Bellas de Romariz,Fabiano Pries Devide,Sebasti?o Votre
Movimento , 2007,
Abstract: El libro Atleta, sustantivo femenino: las mujeres brasile as en los juegos olímpicos, publicado en 2006 por Oscar Valporto, reúne cuentos e historias de vida de veinte atletas olímpicas construidas a partir de relatos personales que describen el trayecto de las mujeres atletas brasile as desde su primera participación en 1932 en los Juegos Olímpicos de Los ángeles, hasta la conquista de la tan so ada primera medalla olímpica, en Atlanta, 1996. Los cuentos de la obra relatan las carreras deportivas, resaltando las barreras sociales transpuestas por cada una de esas atletas pioneras. El libro se divide en cuatro partes: empieza con los trayectos de las pioneras del deporte en las modalidades natación y atletismo e finaliza con las atletas de la primera generación que ha ganado medallas olímpicas. Las mujeres referidas como pionerasson: Maria Lenk e Mary Dalva - natación; Wanda e Aída dos Santos - atletismo. El autor sigue destacando las atletas olímpicas Maria Elisa (natación), Isabel (voleibol); Luisa Parente (gimnástica olímpica) e Soraia (judo). El libro muestra también las reinas de las arenas: Jackie, M nica, Adriana, Sandra, Adriana Behar e Shelda, e se cierra con las mujeres que conquistaron las medallas en los deportes colectivos: Paula e Janeth (básquet), Leila e Virna (voleibol de cuadra) e Pretinha e Marta (fútbol de campo). La obra está direccionada a los amantes del deporte nacional e de la historia, e aunque no presente un texto en el formato académico, tiene su mérito por ser pionero en la tarea de rescatar tales trayectos, ofreciendo a los profesionales de la educación física la posibilidad de realizar debates relevantes sobre las cuestiones de género en la escuela.
Anomaly Detection Based on Confidence Intervals Using SOM with an Application to Health Monitoring
Anastasios Bellas,Charles Bouveyron,Marie Cottrell,Jerome Lacaille
Statistics , 2015, DOI: 10.1007/978-3-319-07695-9_14
Abstract: We develop an application of SOM for the task of anomaly detection and visualization. To remove the effect of exogenous independent variables, we use a correction model which is more accurate than the usual one, since we apply different linear models in each cluster of context. We do not assume any particular probability distribution of the data and the detection method is based on the distance of new data to the Kohonen map learned with corrected healthy data. We apply the proposed method to the detection of aircraft engine anomalies.
Malforma o de Chiari do tipo II sintomática
Arquivos de Neuro-Psiquiatria , 1998,
Abstract: Os autores analisam uma série de 17 crian as portadoras de mielodisplasias que desenvolveram sinais e sintomas da malforma o de Chiari do tipo II. De acordo com a idade, dois grupos ficaram bem definidos: Grupo I, crian as no primeiro ano de vida, em que predominaram sinais e sintomas de comprometimento do tronco encefálico e nervos cranianos bulbares (n=13); Grupo II, composto por crian as com idade superior a um ano, em que as principais manifesta es foram dor cervical e sinais cerebelares (n=4). O resultado do tratamento cirúrgico nos dois grupos foi distinto: enquanto a mortalidade no Grupo I atingiu 46,1%, nenhum paciente do Grupo II veio a falecer. O tratamento inicial consistiu na instala o ou revis o de deriva o ventricular, sendo a descompress o cranio-vertebral reservada àqueles que n o se beneficiaram com esses procedimentos. Os autores enfatizam a necessidade do imediato reconhecimento e tratamento do quadro, de modo a se obter resultados satisfatórios.
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