439 research outputs found

    The Kinematics of the Ionized and Molecular Hydrogen in the Starburst Galaxy NGC 253

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    Near-infrared H_2 1-0 S(1) and Br_gamma velocity curves along the major axis of NGC 253 have revealed a central velocity gradient that is seven times steeper than that shown by the optical velocity curve. This is interpreted as an optical depth effect due to dust. Approximately 35 mag of visual extinction in the center is required to match the SW side of the optical velocity curve. The spatial variation of the ratio of these lines to the CO (J=1-0) line is compared among starburst galaxies NGC 253, M82, and NGC 4945 to investigate the excitation mechanism responsible for the H_2 1-0 S(1) line.Comment: Uuencoded postscript file, 10 pages (4 tables included), 8 figures available on request to [email protected], Ap.J. (in press

    Alarm compliance in healthcare: Design considerations for actionable alarms (in intensive care units)

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    Intensive care units are technologically advanced environments that are designed to safeguard the patient while their vitals are stabilized for further treatment. Audible and visual alarms are part of the healthcare ecology. However, these alarms are so many that clinicians suffer from a syndrome called "alarm fatigue" and often do not comply with the task alarm is conveying. Measuring compliance with rules in the workspace and determining the success of a system belongs to the field of ergonomics and is based on data collected through task observations and scoring. In this paper, we will explore compliance with critical alarms by not only from their potential success or failure perspective but also from the perspectives of the clinician capacity, needs, and motivations to comply with alarms in critical environments. We will finally, reflect on further possible design strategies to increase compliance in critical care that are beyond following rules per se but through intrinsic motivation

    Comparative sequence analysis of the complete set of 40S ribosomal proteins in the Senegalese sole (Solea senegalensis Kaup) and Atlantic halibut (Hippoglossus hippoglossus L.) (Teleostei: Pleuronectiformes): phylogeny and tissue- and development-specific expression

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    Background: Ribosomal proteins (RPs) are key components of ribosomes, the cellular organelle responsible for protein biosynthesis in cells. Their levels can vary as a function of organism growth and development; however, some RPs have been associated with other cellular processes or extraribosomal functions. Their high representation in cDNA libraries has resulted in the increase of RP sequences available from different organisms and their proposal as appropriate molecular markers for phylogenetic analysis. Results: The development of large-scale genomics of Senegalese sole (Solea senegalensis) and Atlantic halibut (Hippoglossus hippoglossus), two commercially important flatfish species, has made possible the identification and systematic analysis of the complete set of RP sequences for the small (40S) ribosome subunit. Amino acid sequence comparisons showed a high similarity both between these two flatfish species and with respect to other fish and human. EST analysis revealed the existence of two and four RPS27 genes in Senegalese sole and Atlantic halibut, respectively. Phylogenetic analysis clustered RPS27 in two separate clades with their fish and mammalian counterparts. Steady-state transcript levels for eight RPs (RPS2, RPS3a, RPS15, RPS27-1, RPS27-2, RPS27a, RPS28, and RPS29) in sole were quantitated during larval development and in tissues, using a real-time PCR approach. All eight RPs exhibited different expression patterns in tissues with the lowest levels in brain. On the contrary, RP transcripts increased co-ordinately after first larval feeding reducing progressively during the metamorphic process. Conclusion: The genomic resources and knowledge developed in this survey will provide new insights into the evolution of Pleuronectiformes. Expression data will contribute to a better understanding of RP functions in fish, especially the mechanisms that govern growth and development in larvae, with implications in aquaculture.Peer reviewed: YesNRC publication: Ye

    Estudio mineralógico de las arcillas cerámicas de Pereruela (Zamora)

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    Trabajo financiado por el Instituto de Estudios Zamoranos Florián de Ocampo.Peer reviewe

    Los problemas de matemáticas escolares de primaria, ¿son solo problemas para el aula?

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    Resolver problemas de matemáticas es una tarea cognitivamente compleja que se realiza en las aulas de primaria de la mayor parte de los países del mundo, uno de cuyos objetivos es conectar las matemáticas escolares con la vida real. Por otro lado, los libros de texto se utilizan como material fundamental de aprendizaje en primaria en la mayor parte de los países del mundo. En este trabajo se pretende caracterizar el grado de autenticidad de los problemas presentes en los libros de texto y cuadernillos complementarios de los seis cursos de primaria de una de las editoriales más utilizadas en España y Latinoamérica, adaptando el sistema de análisis creado por Palm y depurado por Depaepe. Los resultados muestran una escasez de problemas auténticos en los diversos cursos, decreciendo según se aumenta del nivel de escolaridad

    Infrared Study of Fullerene Planetary Nebulae

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    We present a study of 16 PNe where fullerenes have been detected in their Spitzer spectra. This large sample of objects offers an unique opportunity to test conditions of fullerene formation and survival under different metallicity environments as we are analyzing five sources in our own Galaxy, four in the LMC, and seven in the SMC. Among the 16 PNe under study, we present the first detection of C60 (possibly also C70) fullerenes in the PN M 1-60 as well as of the unusual 6.6, 9.8, and 20 um features (possible planar C24) in the PN K 3-54. Although selection effects in the original samples of PNe observed with Spitzer may play a potentially significant role in the statistics, we find that the detection rate of fullerenes in C-rich PNe increases with decreasing metallicity (5% in the Galaxy, 20% in the LMC, and 44% in the SMC). CLOUDY photoionization modeling matches the observed IR fluxes with central stars that display a rather narrow range in effective temperature (30,000-45,000 K), suggesting a common evolutionary status of the objects and similar fullerene formation conditions. The observed C60 intensity ratios in the Galactic sources confirm our previous finding in the MCs that the fullerene emission is not excited by the UV radiation from the central star. CLOUDY models also show that line- and wind-blanketed model atmospheres can explain many of the observed [NeIII]/[NeII] ratios by photoionization suggesting that possibly the UV radiation from the central star, and not shocks, are triggering the decomposition of the circumstellar dust grains. With the data at hand, we suggest that the most likely explanation for the formation of fullerenes and graphene precursors in PNe is that these molecular species are built from the photo-chemical processing of a carbonaceous compound with a mixture of aromatic and aliphatic structures similar to that of HAC dust.Comment: Accepted for publication in ApJ (43 pages, 11 figures, and 4 tables). Small changes to fit the proof-corrected article to be published in Ap
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