76 research outputs found

    ALMA Observations of Giant Molecular Clouds in the Starburst Dwarf Galaxy Henize 2-10

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    We present new 12{ }^{12}CO(J=1-0) observations of Henize 2-10, a blue compact dwarf galaxy about 8.7 Mpc away, taken with the Atacama Large Millimeter Array. These are the highest spatial and spectral resolution observations, to date, of the molecular gas in this starburst galaxy. We measure a molecular mass of 1.2×108M1.2\times10^8 M_\odot in Henize 2-10, and most of the molecular gas is contained within a region having a size of about 310 pc. We use the CPROPS algorithm to identify 119 resolved giant molecular clouds distributed throughout the galaxy, and the molecular gas contained within these clouds make up between 45 to 70% of the total molecular mass. The molecular clouds in Henize 2-10 have similar median sizes (~26 pc), luminous masses (~4×105 4\times 10^5 MM_\odot), and surface densities (~180180 MM_\odot pc2^{-2}) to Milky Way clouds. We provide evidence that Henize 2-10 clouds tend to be in virial equilibrium, with the virial and luminous masses scaling according to MvirMlum1.2±0.1M_{vir}\propto M_{lum}^{1.2\pm0.1}, similar to clouds in the Milky Way. However, we measure a scaling relationship between luminous mass and size, MvirR3.0±0.3M_{vir}\propto R^{3.0\pm0.3}, that is steeper than what is observed in Milky Way clouds. Assuming Henize 2-10 molecular clouds are virialized, we infer values of the CO-to-H2_2 conversion factor ranging from 0.5 to 13 times the standard value in the Solar Neighborhood. Given star formation efficiencies as low as 5%, the most massive molecular clouds in Henize 2-10 currently have enough mass to form the next generation of super-star clusters in the galaxy

    Period-Luminosity Relations Derived from the OGLE-III Fundamental Mode Cepheids

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    In this Paper, we have derived Cepheid period-luminosity (P-L) relations for the Large Magellanic Cloud (LMC) fundamental mode Cepheids, based on the data released from OGLE-III. We have applied an extinction map to correct for the extinction of these Cepheids. In addition to the VIW band P-L relations, we also include JHK and four Spitzer IRAC band P-L relations, derived by matching the OGLE-III Cepheids to the 2MASS and SAGE datasets, respectively. We also test the non-linearity of the Cepheid P-L relations based on extinction-corrected data. Our results (again) show that the LMC P-L relations are non-linear in VIJH bands and linear in KW and the four IRAC bands, respectively.Comment: 6 pages, 3 figures and 3 tables, ApJ accepte

    PII: S1360-1385(00)01652-6

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    T he challenge for today's scientists is to maintain a broad perspective of interactive signaling pathways, while dissecting their parts sufficiently to render them understandable. Our goal is to stimulate the reader to consider the phosphoinositide (PI) pathway as a functional component of a complex growth response and to move beyond the reductionist's perspective of confining PI signaling to the generation of a transient, Ins(1,4,5)P 3 -induced Ca 2ϩ oscillation. (For additional coverage of plant PIs and the enzymes involved in their metabolism see Refs 1,2.) Inositol phospholipids as regulators of growth Most plant responses to external stimuli involve a change in growth and therefore membrane biogenesis. Membrane trafficking and signaling are inexorably linked in regulating cellular metabolism and controlling growth. To coordinate these processes, evolution appears to have capitalized on the stereospecificity of the PIs. During membrane trafficking, individual inositol phospholipids on the vesicle surface specify functional information like cogs on a wheel. As vesicles traffic from the endoplasmic reticulum (ER) to the plasma membrane, and from the ER to the vacuole and retrograde pathways, inositol phospholipids attract specific proteins necessary for budding, docking and fusion Biosynthesis and function of PtdIns(3) P The first evidence for the exacting requirements for stereospecific isomers of phosphatidylinositol (PtdIns) phosphate in membrane trafficking was revealed when the gene for yeast PtdIns-3-kinase, VPS34, was shown to be essential for trafficking of hydrolytic enzymes to the vacuole 5 . The plant PtdIns-3-kinase is related to the yeast Vps34p, which uses only PtdIns as a substrate. In plants, PtdIns-3-kinase activity is associated with nodule formation during symbiotic nitrogen fixation Exploiting yeast genetics to demonstrate the necessity of PtdIns(4)P in membrane trafficking and to elucidate the physiological roles of the distinct PtdIns-4-kinase isoforms has corroborated these findings. In an elegant mutant screen, yeast mutants were identified that were compromised in various steps of intracellular lipid transpor

    Gathering dust : A galaxy-wide study of dust emission from cloud complexes in NGC 300

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    © 2018 ESO. Reproduced with permission from Astronomy & Astrophysics. Content in the UH Research Archive is made available for personal research, educational, and non-commercial purposes only. Unless otherwise stated, all content is protected by copyright, and in the absence of an open license, permissions for further re-use should be sought from the publisher, the author, or other copyright holder.Aims. We use multi-band observations by the Herschel Space Observatory to study the dust emission properties of the nearby spiral galaxy NGC 300. We compile a first catalogue of the population of giant dust clouds (GDCs) in NGC 300, including temperature and mass estimates, and give an estimate of the total dust mass of the galaxy. Methods. We carried out source detection with the multiwavelength source extraction algorithm getsources. We calculated physical properties, including mass and temperature, of the GDCs from five-band Herschel PACS and SPIRE observations from 100 to 500 μm; the final size and mass estimates are based on the observations at 250 μm that have an effective spatial resolution of ~170 pc. We correlated our final catalogue of GDCs to pre-existing catalogues of HII regions to infer the number of GDCs associated with high-mass star formation and determined the Hα emission of the GDCs. Results. Our final catalogue of GDCs includes 146 sources, 90 of which are associated with known HII regions. We find that the dust masses of the GDCs are completely dominated by the cold dust component and range from ~1.1 × 10 3 to 1.4 × 10 4 M. The GDCs have effective temperatures of ~13-23 K and show a distinct cold dust effective temperature gradient from the centre towards the outer parts of the stellar disk. We find that the population of GDCs in our catalogue constitutes ~16% of the total dust mass of NGC 300, which we estimate to be about 5.4 × 10 6 M. At least about 87% of our GDCs have a high enough average dust mass surface density to provide sufficient shielding to harbour molecular clouds. We compare our results to previous pointed molecular gas observations in NGC 300 and results from other nearby galaxies and also conclude that it is very likely that most of our GDCs are associated with complexes of giant molecular clouds.Peer reviewe

    Field Epidemiology and Laboratory Training Programs in sub-Saharan Africa from 2004 to 2010: need, the process, and prospects

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    As of 2010 sub-Saharan Africa had approximately 865 million inhabitants living with numerous public health challenges. Several public health initiatives [e.g., the United States (US) President’s Emergency Plan for AIDS Relief and the US President’s Malaria Initiative] have been very successful at reducing mortality from priority diseases. A competently trained public health workforce that can operate multi-disease surveillance and response systems is necessary to build upon and sustain these successes and to address other public health problems. Sub-Saharan Africa appears to have weathered the recent global economic downturn remarkably well and its increasing middle class may soon demand stronger public health systems to protect communities. The Epidemic Intelligence Service (EIS) program of the US Centers for Disease Control and Prevention (CDC) has been the backbone of public health surveillance and response in the US during its 60 years of existence. EIS has been adapted internationally to create the Field Epidemiology Training Program (FETP) in several countries. In the 1990s CDC and the Rockefeller Foundation collaborated with the Uganda and Zimbabwe ministries of health and local universities to create 2-year Public Health Schools Without Walls (PHSWOWs) which were based on the FETP model. In 2004 the FETP model was further adapted to create the Field Epidemiology and Laboratory Training Program (FELTP) in Kenya to conduct joint competencybased training for field epidemiologists and public health laboratory scientists providing a master’s degree to participants upon completion. The FELTP model has been implemented in several additional countries in sub-Saharan Africa. By the end of 2010 these 10 FELTPs and two PHSWOWs covered 613 million of the 865 million people in sub-Saharan Africa and had enrolled 743 public health professionals. We describe the process that we used to develop 10 FELTPs covering 15 countries in sub-Saharan Africa from 2004 to 2010 as a strategy to develop a locally trained public health workforce that can operate multi-disease surveillance and response systems.Key words: Field epidemiology, laboratory management, multi-disease surveillance and response systems, public health workforce capacity buildin

    Giant Molecular Clouds in the Early-type Galaxy NGC 4526

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    D. Utomo, et al., “Giant Molecular Clouds in the Early-Type Galaxy NGC 4526”, The Astrophysical Journal, Vol. 803(1), April 2015. © 2015. The American Astronomical Society. All rights reserved.We present a high spatial resolution (≈20 pc) of 12CO(2 −1) observations of the lenticular galaxy NGC 4526. We identify 103 resolved giant molecular clouds (GMCs) and measure their properties: size R, velocity dispersion σv, and luminosity L. This is the first GMC catalog of an early-type galaxy. We find that the GMC population in NGC 4526 is gravitationally bound, with a virial parameter α ∼ 1. The mass distribution, dN/dM ∝ M−2.39 ± 0.03, is steeper than that for GMCs in the inner Milky Way, but comparable to that found in some late-type galaxies. We find no size–line width correlation for the NGC 4526 clouds, in contradiction to the expectation from Larson’s relation. In general, the GMCs in NGC 4526 are more luminous, denser, and have a higher velocity dispersion than equal-size GMCs in the Milky Way and other galaxies in the Local Group. These may be due to higher interstellar radiation field than in the Milky Way disk and weaker external pressure than in the Galactic center. In addition, a kinematic measurement of cloud rotation shows that the rotation is driven by the galactic shear. For the vast majority of the clouds, the rotational energy is less than the turbulent and gravitational energy, while the four innermost clouds are unbound and will likely be torn apart by the strong shear at the galactic center. We combine our data with the archival data of other galaxies to show that the surface density Σ of GMCs is not approximately constant, as previously believed, but varies by ∼3 orders of magnitude. We also show that the size and velocity dispersion of the GMC population across galaxies are related to the surface density, as expected from the gravitational and pressure equilibrium, i.e., σv R−1/2 ∝ Σ1/2.Peer reviewe

    A High Resolution Study of the HI-H2 Transition across the Perseus Molecular Cloud

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    To investigate the fundamental principles of H2 formation in a giant molecular cloud (GMC), we derive the HI and H2 surface density (Sigma_HI and Sigma_H2) images of the Perseus molecular cloud on sub-pc scales (~0.4 pc). We use the far-infrared data from the Improved Reprocessing of the IRAS Survey and the V-band extinction image provided by the COMPLETE Survey to estimate the dust column density image of Perseus. In combination with the HI data from the Galactic Arecibo L-band Feed Array HI Survey and an estimate of the local dust-to-gas ratio, we then derive the Sigma_H2 distribution across Perseus. We find a relatively uniform Sigma_HI ~ 6-8 Msun pc^-2 for both dark and star-forming regions, suggesting a minimum HI surface density required to shield H2 against photodissociation. As a result, a remarkably tight and consistent relation is found between Sigma_H2/Sigma_HI and Sigma_HI+Sigma_H2. The transition between the HI- and H2-dominated regions occurs at N(HI)+2N(H2) ~ (8-14) x 10^20 cm^-2. Our findings are consistent with predictions for H2 formation in equilibrium, suggesting that turbulence may not be of primary importance for H2 formation. However, the importance of a warm neutral medium for H2 shielding, an internal radiation field, and the timescale of H2 formation still remain as open questions. We also compare H2 and CO distributions and estimate the fraction of "CO-dark" gas, f_DG ~ 0.3. While significant spatial variations of f_DG are found, we do not find a clear correlation with the mean V-band extinction.Comment: updated to match the final version published in April 201

    Meta-analysis of the space flight and microgravity response of the Arabidopsis plant transcriptome

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    15 p.-8 fig.-2 tab.Spaceflight presents a multifaceted environment for plants, combining the effects on growth of many stressors and factors including altered gravity, the influence of experiment hardware, and increased radiation exposure. To help understand the plant response to this complex suite of factors this study compared transcriptomic analysis of 15 Arabidopsis thaliana spaceflight experiments deposited in the National Aeronautics and Space Administration’s GeneLab data repository. These data were reanalyzed for genes showing significant differential expression in spaceflight versus ground controls using a single common computational pipeline for either the microarray or the RNA-seq datasets. Such a standardized approach to analysis should greatly increase the robustness of comparisons made between datasets. This analysis was coupled with extensive cross-referencing to a curated matrix of metadata associated with these experiments. Our study reveals that factors such as analysis type (i.e., microarray versus RNA-seq) or environmental and hardware conditions have important confounding effects on comparisons seeking to define plant reactions to spaceflight. The metadata matrix allows selection of studies with high similarity scores, i.e., that share multiple elements of experimental design, such as plant age or flight hardware. Comparisons between these studies then helps reduce the complexity in drawing conclusions arising from comparisons made between experiments with very different designs.This work was coordinated through the GeneLab Plant Analysis Working Group and was supported by NASA grants 80NSSC19K0126, 80NSSC18K0132 and 80NSSC21K0577 to S.G. and R.B., through NASA 80NSSC19K1481 to S.W., NNX15AG55G to C.W., and NNX15AG56G to L.D. and N.L., from the Spanish Agencia Estatal de Investigación grant RTI2018-099309-B-I00 and ESA 1340112 4000131202/20/NL/PG/pt to R.H. Contributions from P.J. and P.G. were partially supported by funds from the Oregon State University, NSF awards 1127112 and 1340112 and the United States Department of Agriculture, Agriculture Research Service. The Qlik software used in this work is provided under a free-to-use educational license from Qlik Technologies Inc. GeneLab datasets were obtained from https://genelab-data.ndc.nasa.gov/genelab/projects/, maintained by NASA GeneLab, NASA Ames Research Center, Moffett Field, CA 94035.Peer reviewe

    Star clusters near and far; tracing star formation across cosmic time

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    © 2020 Springer-Verlag. The final publication is available at Springer via https://doi.org/10.1007/s11214-020-00690-x.Star clusters are fundamental units of stellar feedback and unique tracers of their host galactic properties. In this review, we will first focus on their constituents, i.e.\ detailed insight into their stellar populations and their surrounding ionised, warm, neutral, and molecular gas. We, then, move beyond the Local Group to review star cluster populations at various evolutionary stages, and in diverse galactic environmental conditions accessible in the local Universe. At high redshift, where conditions for cluster formation and evolution are more extreme, we are only able to observe the integrated light of a handful of objects that we believe will become globular clusters. We therefore discuss how numerical and analytical methods, informed by the observed properties of cluster populations in the local Universe, are used to develop sophisticated simulations potentially capable of disentangling the genetic map of galaxy formation and assembly that is carried by globular cluster populations.Peer reviewedFinal Accepted Versio

    POR UM PROCESSO DE PROJETO DE ARQUITETURA HOSPITALAR CENTRADO NO AFETO

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    Planned as spaces for health recovery, hospitals are sources of traumatic and stressful experiences. In this context, affect is a psychophysiological human response to the direct impact of the environment. Despite advances in hospital architecture and its constructive efficiency, modernity, and ‘clean’ appearance, subjective aspects such as value, ethics, and user affect are not usually considered in requirements or modeling parameters. This paper presents a theoretical-methodological framework to embrace the affective dimension in architectural design practice by reviewing the literature on Spinoza’s theory of affect, psychoevolutionism, attention restoration, and Value Sensitive Design (VSD). These theories can be considered potential factors to be objectively translated into hospital architectural design requirements.  Planejados como espaços de recuperação da saúde, os hospitais são fonte de experiências traumáticas e estressantes. Nesse contexto, a dimensão afetiva faz parte da resposta humana ao impacto direto que o ambiente exerce sobre o processo psicofisiológico. Apesar dos avanços na arquitetura hospitalar, sua eficiência construtiva e aparência moderna e ‘clean’, aspectos subjetivos como valor, ética e afetos dos usuários não são levados em consideração nos requisitos ou parâmetros de modelagem. Este artigo apresenta sinteticamente o arcabouço teórico metodológico com vistas a consideração da dimensão afetiva na prática projetual, por meio de revisão da literatura sobre o afeto de Espinosa, as teorias do psicoevolucionismo, restauração da atenção, bem como Value Sensitive Design (VSD). Observou-se que os elementos das referidas teorias podem ser considerados como afetos potenciais a serem traduzidos objetivamente em requisitos de projetos arquitetônicos hospitalares.  Planejados como espaços de recuperação da saúde, os hospitais são fonte de experiências traumáticas e estressantes envolvendo dor, perda de controle e privação do ambiente familiar. Nesse contexto, a dimensão afetiva faz parte da resposta humana ao impacto direto que o ambiente exerce sobre o processo psicofisiológico. Apesar dos avanços na arquitetura hospitalar, economizando recursos com eficiência construtiva, sua aparência moderna e 'clean'; aspectos subjetivos como valor, ética e afetos do usuário não são levados em consideração em requisitos ou parâmetros de modelagem. A metodologia consistiu em uma breve revisão da literatura sobre o 'afeto de Spinoza', as teorias do 'psicoevolucionismo', 'restauração da atenção', bem como 'Value Sensitive Design' [VSD]. Observou-se que os elementos da teoria dos ambientes restauradores podem, com base na ética de Spinoza, ser considerados como afetos/afetos potenciais que podem ser traduzidos objetivamente em requisitos de projeto pela metodologia adaptada do DSV.
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