287 research outputs found
New Observations of Extra-Disk Molecular Gas in Interacting Galaxy Systems, Including a Two-Component System in Stephan's Quintet
We present new CO (1 - 0) observations of eleven extragalactic tails and
bridges in nine interacting galaxy systems, almost doubling the number of such
features with sensitive CO measurements. Eight of these eleven features were
undetected in CO to very low CO/HI limits, with the most extreme case being the
NGC 7714/5 bridge. This bridge contains luminous H II regions and has a very
high HI column density (1.6 X 10^21 cm^-2 in the 55" CO beam), yet was
undetected in CO to rms T(R)* = 2.4 mK. The HI column density is higher than
standard H2 and CO self-shielding limits for solar-metallicity gas, suggesting
that the gas in this bridge is metal-poor and has an enhanced N(H2)/I(CO) ratio
compared to the Galactic value. Only one of the eleven features in our sample
was unambiguously detected in CO, a luminous HI-rich star formation region near
an optical tail in the compact group Stephan's Quintet. We detect CO at two
widely separated velocities in this feature, at ~6000 km/s and ~6700 km/s. Both
of these components have HI and H-alpha counterparts. These velocities
correspond to those of galaxies in the group, suggesting that this gas is
material that has been removed from two galaxies in the group. The
CO/HI/H-alpha ratios for both components are similar to global values for
spiral galaxies.Comment: 39 pages, Latex, 15 figures, Astronomical Journal, in pres
The Link Between Star Formation and Accretion in LINERs: A Comparison with other AGN Subclasses
We present archival high resolution X-ray imaging observations of 25 nearby
LINERs observed by ACIS on board Chandra. This sample builds on our previously
published proprietary and archival X-ray observations, and includes the
complete set of LINERs with published black hole masses and FIR luminosities
that have been observed by Chandra. Of the 82 LINERs observed by Chandra, 41
(50%) display hard nuclear cores consistent with an AGN. The nuclear 2-10 keV
luminosities of these AGN-LINERs range from ~ 2 X 10^38 ergs s^-1 to ~ 1 X
10^44 ergs s^-1. Reinforcing our previous work, we find a significant
correlation between the Eddington ratio, L bol/LEdd, and the far-IR (FIR)
luminosity, LFIR, as well as the IR brightness ratio, LFIR/LB in the host
galaxy of AGN-LINERs that extends over seven orders of magnitude in Lbol/LEdd.
Combining our AGN-LINER sample with galaxies from other AGN subclasses, we find
that this correlation is reinforced in the full sample of 129 AGN, extending
over almost nine orders of magnitude in Lbol/LEdd. Using archival and
previously published observations of the 6.2 mm PAH feature from the Infrared
Space Observatory (ISO), we find that it is unlikely that dust heating by the
AGN dominates the FIR luminosity in our sample of AGN. Our results may
therefore imply a fundamental link between the mass accretion rate (Mdot), as
measured by the Eddington ratio, and the star formation rate (SFR), as measured
by the FIR luminosity.Comment: 22 pages, 11 figures. Paper excepted for publication by ApJ in
Novembe
Multiwavelength Study of the Starburst Galaxy NGC 7714. II: The Balance between Young, Intermediate Age and Old Stars
We combine existing multiwavelength data (incl. an HST/GHRS UV spectrum, an
optical spectrum, far-IR, Xray and radio fluxes) with new HST/WFPC2 images,
near-IR photometry and K band spectroscopy. We use these data to constrain the
young, the intermediate age and the old stellar populations in the central 330
pc of the starburst galaxy NGC 7714. [...]
We find that the young burst responsible for the UV light is only a small
part of an extended episode of enhanced star formation (SF) [...]. The mass of
young and intermediate age stars thus formed equals at least 10% of the mass
locked in pre-existing stars of the underlying galaxy nucleus [...]. The
spectrophotometric SF timescale is long compared to the ~110 Myr elapsed since
closest contact with NGC 7715. The trigger of the starburst remains elusive.
NGC 7714 owes its brightness in the UV to a few low extinction lines of sight
towards young stars. [...] The different extinction estimates obtained from
different indicators result naturally from the coexistence of populations with
various ages and obscurations. The near-IR continuum image looks smoothest, as
a consequence of lower sensitivity to extinction and of a larger contribution
of old stars. We compare the nuclear properties of NGC 7714 with results from
studies in larger apertures. We emphasize that the global properties of
starburst galaxies are the result of the averaging over many lines of sight
with diverse properties in terms of obscuration and stellar ages.Comment: 29 pages (+20 figures and tables), Latex2e (figs. included), uses
aastex.cls. To be published in ApJ (May 2001 issue
The Herschel Exploitation of Local Galaxy Andromeda (HELGA). I: Global far-infrared and sub-mm morphology
We have obtained Herschel images at five wavelengths from 100 to 500 micron
of a ~5.5x2.5 degree area centred on the local galaxy M31 (Andromeda), our
nearest neighbour spiral galaxy, as part of the Herschel guaranteed time
project "HELGA". The main goals of HELGA are to study the characteristics of
the extended dust emission, focusing on larger scales than studied in previous
observations of Andromeda at an increased spatial resolution, and the obscured
star formation. In this paper we present data reduction and Herschel maps, and
provide a description of the far-infrared morphology, comparing it with
features seen at other wavelengths. We use high--resolution maps of the atomic
hydrogen, fully covering our fields, to identify dust emission features that
can be associated to M31 with confidence, distinguishing them from emission
coming from the foreground Galactic cirrus. Thanks to the very large extension
of our maps we detect, for the first time at far-infrared wavelengths, three
arc-like structures extending out to ~21, ~26 and ~31 kpc respectively, in the
south-western part of M31. The presence of these features, hosting ~2.2e6 Msol
of dust, is safely confirmed by their detection in HI maps. Overall, we
estimate a total dust mass of ~5.8e7 Msol, about 78% of which is contained in
the two main ring-like structures at 10 and 15 kpc, at an average temperature
of 16.5 K. We find that the gas-to-dust ratio declines exponentially as a
function of the galacto-centric distance, in agreement with the known
metallicity gradient, with values ranging from 66 in the nucleus to ~275 in the
outermost region. [Abridged]Comment: 15 Pages, 9 Figures. Accepted for publication in Astronomy and
Astrophysics. A high resolution version of the paper can be found at
http://wazn.ugent.be/jfritz/HelgaI_final.pd
The possibility of critical realist randomised controlled trials.
BACKGROUND: Some realists have criticised randomised controlled trials for their inability to explain the causal relations that they identify; to take into account the influence of the social context of the interventions they evaluate; and to account for individual difference. However, among realists, there is controversy over whether it is possible to improve trials by making them realist, or whether realism and the philosophical assumptions underlying trials are incompatible. This paper contributes to the debate in Trials on this issue. The debate thus far has concentrated on the possibility of combining trial methodology with that of realist evaluation. MAIN BODY: We concur with the contention that it is not feasible to combine randomised controlled trial design with the realist evaluation approach. However, we argue that a different variant of realism, critical realism, provides a more appropriate theoretical grounding for realist trials. In contrast to realist evaluation, which regards social mechanisms as an amalgam of social resources and people's reasoning, critical realism insists on their distinction. It does so on the basis of its assertion of the need to distinguish between social structures (in which resources lie) and human agency (which is at least partly guided by reasoning). From this perspective, conceiving of social mechanisms as external to participants can be seen as a valid methodological strategy for supplementing the exclusive concentration of trials on outcomes. While accepting realist evaluation's insistence that causality in open systems involves a configuration of multiple generative mechanisms, we adopt the critical realist interpretation of the experimental method, which sees it as creating artificial closure in order to identify the effects of specific causal mechanisms. If randomised controlled trials can be regarded as epidemiological proxies that substitute probabilistic controls over extraneous factors for closed experiments, their examination of the powers of discrete mechanisms through observation of the variation of outcomes is appropriate. CONCLUSION: While there are still issues to be resolved, critical realist randomised controlled trials are possible and have the potential to overcome some of the difficulties faced by traditional trial designs in accounting for the influence of social context and individual interpretation
Social determinants of duration of last nursing home stay at the end of life in Switzerland: a retrospective cohort study
Integrase Inhibitors are Associated with Neuropsychiatric Symptoms in Women with HIV
Objective: Women with HIV(WWH) are more likely to discontinue/change antiretroviral therapy(ART) due to side effects including neuropsychiatric symptoms. Efavirenz and integrase strand transfer inhibitors(INSTIs) are particularly concerning. We focused on these ART agents and neuropsychiatric symptoms in previously developed subgroups of WWH that differed on key sociodemographic factors as well as longitudinal behavioral and clinical profiles. WWH from the Womenâs Interagency HIV Study were included if they had ART data available, completed the Perceived Stress Scale-10 and PTSD Checklist-Civilian. Questionnaires were completed biannually beginning in 2008 through 2016. To examine ART-symptom associations, constrained continuation ratio model via penalized maximum likelihood were fit within 5 subgroups of WWH. Data from 1882 WWH contributed a total of 4598 observations. 353 women were previously defined as primarily having well-controlled HIV with vascular comorbidities, 463 with legacy effects(CD4 nadir < 250cells/mL), 274 aged †45 with hepatitis, 453 between 35â55 years, and 339 with poorly-controlled HIV/substance users. INSTIs, but not efavirenz, were associated with symptoms among key subgroups of WWH. Among those with HIV legacy effects, dolutegravir and elvitegravir were associated with greater stress/anxiety and avoidance symptoms(Pâs < 0.01); dolutegravir was also associated with greater re-experiencing symptoms(P = 0.005). Elvitegravir related to greater re-experiencing and hyperarousal among women with well-controlled HIV with vascular comorbidities(Pâs < 0.022). Raltegravir was associated with less hyperarousal, but only among women aged †45 years(P = 0.001). The adverse neuropsychiatric effects of INSTIs do not appear to be consistent across all WWH. Key characteristics (e.g., age, hepatitis positivity) may need consideration to fully weight the riskâbenefit ratio of dolutegravir and elvitegravir in WWH
âItâs not something I chose you knowâ: making sense of pedophilesâ sexual interest in children and the impact on their psychosexual identity
Sexual interest in children is one of the most strongly predictive of the known risk factors for sexual reconviction. It is an important aspect of risk assessment to identify the presence of such interest, and an important task for treatment providers to address such a sexual interest where it is present. It has been argued that understanding pedophilesâ deviant sexual interest in children can enhance risk assessment, management, and treatment planning. This research study aims to explore the phenomenology of deviant sexual interest in children, the impact it has on pedophilic offendersâ identities, and their views on the treatability of that interest. The study used semistructured interviews and repertory grids to make sense of participantsâ experiences. The results revealed three superordinate themes: ââlivingâ with a deviant sexual interest,â ârelational sexual self,â and âpossible and feared sexual self.â The analysis unpacks these themes and repertory grid analysis is used to explore a subset of participantsâ identities in more detail. The results reveal that there needs to be an acceptance from both client and therapist that their sexual interest in children may never go away. Through this acceptance, clients could work on enhancing sexual self-regulation, recognizing their triggers, and so managing their sexual thoughts, feelings, and behavior. Implications for treatment are also discussed
Conservation and divergence within the clathrin interactome of <i>Trypanosoma cruzi</i>
Trypanosomatids are parasitic protozoa with a significant burden on human health. African and American trypanosomes are causative agents of Nagana and Chagas disease respectively, and speciated about 300âmillion years ago. These parasites have highly distinct life cycles, pathologies, transmission strategies and surface proteomes, being dominated by the variant surface glycoprotein (African) or mucins (American) respectively. In African trypanosomes clathrin-mediated trafficking is responsible for endocytosis and post-Golgi transport, with several mechanistic aspects distinct from higher organisms. Using clathrin light chain (TcCLC) and EpsinR (TcEpsinR) as affinity handles, we identified candidate clathrin-associated proteins (CAPs) in Trypanosoma cruzi; the cohort includes orthologs of many proteins known to mediate vesicle trafficking, but significantly not the AP-2 adaptor complex. Several trypanosome-specific proteins common with African trypanosomes, were also identified. Fluorescence microscopy revealed localisations for TcEpsinR, TcCLC and TcCHC at the posterior region of trypomastigote cells, coincident with the flagellar pocket and Golgi apparatus. These data provide the first systematic analysis of clathrin-mediated trafficking in T. cruzi, allowing comparison between protein cohorts and other trypanosomes and also suggest that clathrin trafficking in at least some life stages of T. cruzi may be AP-2-independent
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