47 research outputs found

    Contextual and personal resources in unemployed job search: An intra‐individual perspective

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    Drawing from conservation of resources (COR) theory and the equifinality principle, we challenge the prominent “the‐more‐resources‐the‐better” understanding by examining both the additive and interactive effects of contextual (i.e., networking behaviors and social support) and personal (i.e., job search self‐efficacy) resources on job seeking. Specifically, based on COR theory's resource gain corollary, we propose that higher levels of each resource are positively related to job search intensity and the number of interviews obtained (an additive effect). However, based on the equifinality principle that various resources can contribute to the same goal, we propose that each type of resource can compensate for low levels of the other (an interactive effect). In a four‐wave study following 89 unemployed job seekers over 6 months, we find positive intra‐individual relationships between networking behaviors and job search self‐efficacy with job search intensity. We find that networking behaviors and job search self‐efficacy are also positively related to the number of job interviews obtained and indirectly related through job search intensity for networking behaviors. In line with our predictions, high levels of either networking behaviors or job search self‐efficacy compensate for low levels of the other resource when predicting job search intensity and the number of interviews obtained

    ESO Imaging Survey: infrared observations of CDF-S and HDF-S

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    This paper presents infrared data obtained from observations carried out at the ESO 3.5m New Technology Telescope (NTT) of the Hubble Deep Field South (HDF-S) and the Chandra Deep Field South (CDF-S). These data were taken as part of the ESO Imaging Survey (EIS) program, a public survey conducted by ESO to promote follow-up observations with the VLT. In the HDF-S field the infrared observations cover an area of ~53 square arcmin, encompassing the HST WFPC2 and STIS fields, in the JHKs passbands. The seeing measured in the final stacked images ranges from 0.79" to 1.22" and the median limiting magnitudes (AB system, 2" aperture, 5sigma detection limit) are J_AB~23.0, H_AB~22.8 and K_AB~23.0 mag. Less complete data are also available in JKs for the adjacent HST NICMOS field. For CDF-S, the infrared observations cover a total area of \~100 square arcmin, reaching median limiting magnitudes (as defined above) of J_AB~23.6 and K_AB~22.7 mag. For one CDF-S field H-band data are also available. This paper describes the observations and presents the results of new reductions carried out entirely through the un-supervised, high-throughput EIS Data Reduction System and its associated EIS/MVM C++-based image processing library developed, over the past 5 years, by the EIS project and now publicly available. The paper also presents source catalogs extracted from the final co-added images which are used to evaluate the scientific quality of the survey products, and hence the performance of the software. This is done comparing the results obtained in the present work with those obtained by other authors from independent data and/or reductions carried out with different software packages and techniques. The final science-grade catalogs and co-added images are available at CDS.Comment: Accepted for publication in A&A, 13 pages, 12 figures; a full resolution version of the paper is available from http://www.astro.ku.dk/~lisbeth/eisdata/papers/4528.pdf ; related catalogs and images are available through http://www.astro.ku.dk/~lisbeth/eisdata

    Coexisting conical bipolar and equatorial outflows from a high-mass protostar

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    The BN/KL region in the Orion molecular cloud is an archetype in the study of the formation of stars much more massive than the Sun. This region contains luminous young stars and protostars, but it is difficult to study because of overlying dust and gas. Our basic expectations are shaped to some extent by the present theoretical picture of star formation, the cornerstone of which is that protostars acrete gas from rotating equatorial disks, and shed angular momentum by ejecting gas in bipolar outflows. The main source of the outflow in the BN/KL region may be an object known as radio source I, which is commonly believed to be surrounded by a rotating disk of molecular material. Here we report high-resolution observations of silicon monoxide (SiO) and water maser emission from the gas surrounding source I; we show that within 60 AU (about the size of the Solar System), the region is dominated by a conical bipolar outflow, rather than the expected disk. A slower outflow, close to the equatorial plane of the protostellar system, extends to radii of 1,000 AU.Comment: 10 pages, 2 figures. Accepted by Nature. To appear December 199

    Nuclear obscuration in the high-ionization Seyfert 2 galaxy Tol 0109-383

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    We report the BeppoSAX detection of a hard X-ray excess in the X-ray spectrum of the classical high-ionization Seyfert 2 galaxy Tol0109-383. The X-ray emission of this source observed below 7 keV is dominated by reflection from both cold and ionized gas, as seen in the ASCA data. The excess hard X-ray emission is presumably due to the central source absorbed by an optically thick obscuring torus with N(H)~2e24 cm-2. The strong cold X-ray reflection, if it is produced at the inner surface of the torus, is consistent with the picture where much of the inner nucleus of Tol0109-383 is exposed to direct view, as indicated by optical and infrared properties. However, the X-ray absorption must occur at small radii in order to hide the central X-ray source but leave the optical high-ionization emission line region unobscured. This may also be the case for objects like the Seyfert 1 galaxy Mrk231.Comment: 7 pages, MNRAS in pres

    The density and peculiar velocity fields of nearby galaxies

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    We review the quantitative science that can be and has been done with redshift and peculiar velocity surveys of galaxies in the nearby universe. After a brief background setting the cosmological context for this work, the first part of this review focuses on redshift surveys. The practical issues of how redshift surveys are carried out, and how one turns a distribution of galaxies into a smoothed density field, are discussed. Then follows a description of major redshift surveys that have been done, and the local cosmography out to 8,000 km/s that they have mapped. We then discuss in some detail the various quantitative cosmological tests that can be carried out with redshift data. The second half of this review concentrates on peculiar velocity studies, beginning with a thorough review of existing techniques. After discussing the various biases which plague peculiar velocity work, we survey quantitative analyses done with peculiar velocity surveys alone, and finally with the combination of data from both redshift and peculiar velocity surveys. The data presented rule out the standard Cold Dark Matter model, although several variants of Cold Dark Matter with more power on large scales fare better. All the data are consistent with the hypothesis that the initial density field had a Gaussian distribution, although one cannot rule out broad classes of non-Gaussian models. Comparison of the peculiar velocity and density fields constrains the Cosmological Density Parameter. The results here are consistent with a flat universe with mild biasing of the galaxies relative to dark matter, although open universe models are by no means ruled out.Comment: In press, Physics Reports. 153 pages. gzip'ed postscript of text plus 20 embedded figures. Also available via anonymous ftp at ftp://eku.ias.edu/pub/strauss/review/physrep.p

    Cigarette smoke exposure inhibits extracellular MMP-2 (gelatinase A) activity in human lung fibroblasts

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    BACKGROUND: Exposure to cigarette smoke is considered a major risk factor for the development of lung diseases, since its causative role has been assessed in the induction and maintenance of an inflamed state in the airways. Lung fibroblasts can contribute to these processes, due to their ability to produce proinflammatory chemotactic molecules and extracellular matrix remodelling proteinases. Among proteolytic enzymes, gelatinases A and B have been studied for their role in tissue breakdown and mobilisation of matrix-derived signalling molecules. Multiple reports linked gelatinase deregulation and overexpression to the development of inflammatory chronic lung diseases such as COPD. METHODS: In this study we aimed to determine variations in the gelatinolytic pattern of human lung fibroblasts (HFL-1 cell line) exposed to cigarette smoke extract (CSE). Gelatinolytic activity levels were determined by using gelatin zymography for the in-gel detection of the enzymes (proenzyme and activated forms), and the subsequent semi-quantitative densitometric evaluation of lytic bands. Expression of gelatinases was evaluated also by RT-PCR, zymography of the cell lysates and by western blotting. RESULTS: CSE exposure at the doses used (1–10%) did not exert any significant cytotoxic effects on fibroblasts. Zymographic analysis showed that CSE exposure resulted in a linear decrease of the activity of gelatinase A. Control experiments allowed excluding a direct inhibitory effect of CSE on gelatinases. Zymography of cell lysates confirmed the expression of MMP-2 in all conditions. Semi-quantitative evaluation of mRNA expression allowed assessing a reduced transcription of the enzyme, as well as an increase in the expression of TIMP-2. Statistical analyses showed that the decrease of MMP-2 activity in conditioned media reached the statistical significance (p = 0.0031 for 24 h and p = 0.0012 for 48 h), while correlation analysis showed that this result was independent from CSE cytotoxicity (p = 0.7833 for both exposures). CONCLUSION: Present work describes for the first time that, apart well characterized proinflammatory responses, human lung fibroblasts may react to CSE with a significant reduction of extracellular MMP-2 lytic activity. Therefore, fibroblasts may actively participate to the alteration of the proteolysis/antiproteolysis balance, which reflects the defective repair of the extracellular matrix. Such event should provide a further contribution to the maintenance of the inflamed state in the lungs

    Protoplanetary Disks of T Tauri Binary Systems in the Orion Nebula Cluster

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    We present a study of protoplanetary disks in spatially resolved low-mass binary stars in the Orion Nebula Cluster (ONC) to assess the impact of binarity on the properties of circumstellar disks. This is currently the largest such study in a clustered high-stellar-density star-forming environment. We particularly aim to determine the presence of magnetospheric accretion and dust disks for each binary component, and measure the overall disk frequency. We carried out spatially resolved adaptive-optics-assisted observations to acquire near-IR photometry and spectroscopy of 26 binaries in the ONC, and determine stellar parameters such as effective temperatures, spectral types, luminosities, and masses, as well as accretion properties and near-infrared excesses for the individual binary components. A fraction of 40(+10/-9)% of the binary components in the sample can be inferred to be T Tauri stars possessing an accretion disk, marginally fewer than the disk fraction of single stars. We find that disks in wide binaries of >200AU separation are consistent with random pairing, while the evolution of circumprimary and circumsecondary disks is observed to be synchronized in close binaries (separations <200AU). Circumbinary disks appear to be unsuitable to explain this difference. Furthermore, we identify several mixed pairs of accreting and non-accreting components, suggesting that these systems are common and that there is no preference for either the more or less massive component to evolve faster. The derived accretion luminosities and mass accretion rates of the ONC binary components are of similar magnitude as those for both ONC single stars and binaries in the Taurus star-forming region. The paper concludes with a discussion of the (presumably weak) connection between the presence of inner accretion disks in young binary systems and the existence of planets in stellar multiples.(abridged)Comment: 22 pages, 16 figures. Accepted for publication in Astronomy and Astrophysic

    Cascading Crises: Society in the Age of COVID-19

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    The tsunami of change triggered by the COVID-19 pandemic has transformed society in a series of cascading crises. Unlike disasters that are more temporarily and spatially bounded, the pandemic has continued to expand across time and space for over a year, leaving an unusually broad range of second-order and third-order harms in its wake. Globally, the unusual conditions of the pandemic—unlike other crises—have impacted almost every facet of our lives. The pandemic has deepened existing inequalities and created new vulnerabilities related to social isolation, incarceration, involuntary exclusion from the labor market, diminished economic opportunity, life-and-death risk in the workplace, and a host of emergent digital, emotional, and economic divides. In tandem, many less advantaged individuals and groups have suffered disproportionate hardship related to the pandemic in the form of fear and anxiety, exposure to misinformation, and the effects of the politicization of the crisis. Many of these phenomena will have a long tail that we are only beginning to understand. Nonetheless, the research also offers evidence of resilience on several fronts including nimble organizational response, emergent communication practices, spontaneous solidarity, and the power of hope. While we do not know what the post COVID-19 world will look like, the scholarship here tells us that the virus has not exhausted society’s adaptive potential

    The infrared properties of active extragalactic nuclei

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    In this paper we review the observed infrared properties of the general classes of active extragalactic nuclei with the purpose of relating the observations to the mechanisms responsible for the emission processes. We will first give a summary of those observations which define the energy distributions and emission line ratios of broad groups of objects. We will intersperse measurements of specific features throughout the discussion that illustrate definite emission mechanisms

    Compton Thick AGN: the dark side of the X-ray background

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    The spectrum of the hard X-ray background records the history of accretion processes integrated over the cosmic time. Several pieces of observational and theoretical evidence indicate that a significant fraction of the energy density is obscured by large columns of gas and dust. The absorbing matter is often very thick, with column densities exceeding N_H > 1.5 10^24 cm-2, the value corresponding to unity optical depth for Compton scattering. These sources are called ``Compton thick'' and appear to be very numerous, at least in the nearby universe. Although Compton thick Active Galactic Nuclei (AGN) are thought to provide an important contribution to the overall cosmic energy budget, their space density and cosmological evolution are poorly known. The properties of Compton thick AGN are reviewed here, with particular emphasis on their contributions to the extragalactic background light in the hard X-ray and infrared bands.Comment: 28 pages, 10 figures. Review for "Supermassive Black Holes in the Distant Universe", Ed. A. J. Barger, Kluwer Academi
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