14 research outputs found

    The Spitzer c2d Survey of Large, Nearby, Interstellar Clouds: VI. Perseus Observed with MIPS

    Get PDF
    We present observations of 10.6 square degrees of the Perseus molecular cloud at 24, 70, and 160 microns with the Spitzer Space Telescope Multiband Imaging Photometer for Spitzer (MIPS). The image mosaics show prominent, complex extended emission dominated by illuminating B stars on the East side of the cloud, and by cold filaments of 160 micron emission on the West side. Of 3950 point sources identified at 24 microns, 1141 have 2MASS counterparts. A quarter of these populate regions of the Ks vs. Ks-[24] diagram that are distinct from stellar photospheres and background galaxies, and thus are likely to be cloud members with infrared excess. Nearly half (46%) of these 24 micron excess sources are distributed outside the IC 348 and NGC 1333 clusters. NGC 1333 shows the highest fraction of stars with flat or rising spectral energy distributions (28%), while Class II SEDs are most common in IC 348. These results are consistent with previous relative age determinations for the two clusters. The intercluster region contains several tightly clumped (r~0.1 pc) young stellar aggregates whose members exhibit a wide variety of infrared spectral energy distributions characteristic of different circumstellar environments. One possible explanation is a significant age spread among the aggregate members, such that some have had time to evolve more than others. Alternatively, if the aggregate members all formed at roughly the same time, then remarkably rapid circumstellar evolution would be required to account for the association of Class I and Class III sources at ages <~1 Myr. We highlight important results for several other objects as well (full abstract in the paper).Comment: 82 pages, 32 figures, accepted to ApJS; ALL figures (even line drawings) had to be degraded to be accepted by the system here; the full-res figures are available in the version linked from the 'publications' area available at http://peggysue.as.utexas.edu/SIRTF

    Mudança científica: modelos filosóficos e pesquisa histórica

    Full text link

    Interventions to Improve Health Services and Prevent Tuberculosis for People Living with Human Immunodeficiency Virus in South Africa

    No full text
    Background: South Africa is home to nearly seven million people living with human immunodeficiency virus (PLHIV), for whom tuberculosis (TB) is the leading cause of death. Although national guidelines include effective tactics to prevent TB for PLHIV, implementation has been suboptimal. Objectives: The goal of this dissertation was to evaluate interventions to improve TB prevention for PLHIV in South Africa. We delivered patients' lab results via mobile phone to more quickly recall people with TB or other medically concerning results (Chapter 2). We then sought to improve prescriptions of TB preventive therapy (TPT) with an alternative diagnostic for latent TB infection (LTBI, Chapter 3) and with education campaigns and nurse mentorship (Chapter 4). Methods: For Aim 1, we implemented a non-randomized pilot to compare delivering test results via MatlaMobile versus the standard-of-care. For Aim 2, we conducted a cluster randomized trial to evaluate whether a Quantiferon Gold In-Tube (QGIT) test resulted in more LTBI results being documented and TPT prescriptions than standard-of-care. For Aim 3, we directly observed an intervention and conducted qualitative interviews to characterize implementation outcomes. Results: In Aim 1, patients who received their results via phone were more likely to return to the clinic within seven days, if instructed that their result was medically concerning (20%, n=14/70) than the control group, who were all instructed to return to the clinic to retrieve their results (9%, n=15/174, p=0.02). In Aim 2, clinics documented an absolute 60% (95% CI: 51–68; p <0.001) more LTBI results and 12% (95% CI: –6, 31, p = 0.179) more TPT in QGIT clinics than the standard-of-care, after adjusting for baseline covariates. In Aim 3, the intervention was implemented with moderate fidelity and high uptake, however, nurses questioned whether the intervention could sustain its impact without structural changes. Conclusions: These interventions improved retention-in-care and TB prevention for PLHIV. However, none persuaded patients and nurses to fully adhere to recommended TB/HIV guidelines. Future work should incorporate structural-level interventions, like increased staffing and improved TPT stock management, to better prevent TB among PLHIV

    Mobility and HIV vulnerabilities among female sex workers in Guinea-Bissau: findings from an integrated bio-behavioral survey

    No full text
    Abstract Background Mobility is an important risk determinant for HIV given the potential for intermittent access to HIV services. Mobility may be particularly relevant among female sex workers, (FSW) who have been shown to be at high risk for HIV in settings around the world. Data regarding the role mobility plays in exacerbating HIV risks among FSW across Sub-Saharan Africa remains limited, and data on FSW in Guinea-Bissau is sparse. Methods FSW in four regions of Guinea-Bissau were recruited with a respondent-driven sampling (RDS) method and participated in an integrated bio-behavioral survey between September 27, 2017 and January 26, 2018. Associations between reported general mobility, mobility to or residence in Bissau, and social and HIV vulnerabilities among FSW in Guinea-Bissau were assessed using multivariable logistic regression models. Population proportions were weighted for RDS sampling, while logistic regression models were not. Results Survey respondents included 323 individuals in Bissau, 45 in Bissorã, 140 in Bafatá, and 59 in Gabu. Statistical analyses demonstrated that mobility to more than one destination was significantly associated with recent sex without a condom (ie, sex without a condom within the last three sex acts) with both clients (aOR: 2.47 (95% CI: 1.08, 5.64)) and non-paying partners (aOR: 5.39 (95% CI: 2.61, 11.15)) compared to non-mobility. However, mobility to one or more locations was also associated with higher odds of receiving HIV prevention information, and mobility to more than one location was associated with participating in programming with HIV-related organizations. Conclusions These results suggest that while some prevention services including HIV prevention information reach mobile FSW in Guinea-Bissau more than their non-mobile counterparts, the higher rates of condomless sex among mobile FSW suggest that HIV prevention needs may remain unmet for mobile FSW in Guinea-Bissau. Additionally, the results suggest a nuanced relationship between mobility, place of residence, and HIV and social vulnerabilities and prevention indicators

    Implementation science and stigma reduction interventions in low- and middle-income countries: a systematic review

    No full text
    Abstract Background Interventions to alleviate stigma are demonstrating effectiveness across a range of conditions, though few move beyond the pilot phase, especially in low- and middle-income countries (LMICs). Implementation science offers tools to study complex interventions, understand barriers to implementation, and generate evidence of affordability, scalability, and sustainability. Such evidence could be used to convince policy-makers and donors to invest in implementation. However, the utility of implementation research depends on its rigor and replicability. Our objectives were to systematically review implementation studies of health-related stigma reduction interventions in LMICs and critically assess the reporting of implementation outcomes and intervention descriptions. Methods PubMed, CINAHL, PsycINFO, and EMBASE were searched for evaluations of stigma reduction interventions in LMICs reporting at least one implementation outcome. Study- and intervention-level characteristics were abstracted. The quality of reporting of implementation outcomes was assessed using a five-item rubric, and the comprehensiveness of intervention description and specification was assessed using the 12-item Template for Intervention Description and Replication (TIDieR). Results A total of 35 eligible studies published between 2003 and 2017 were identified; of these, 20 (57%) used qualitative methods, 32 (91%) were type 1 hybrid effectiveness-implementation studies, and 29 (83%) were evaluations of once-off or pilot implementations. No studies adopted a formal theoretical framework for implementation research. Acceptability (20, 57%) and feasibility (14, 40%) were the most frequently reported implementation outcomes. The quality of reporting of implementation outcomes was low. The 35 studies evaluated 29 different interventions, of which 18 (62%) were implemented across sub-Saharan Africa, 20 (69%) focused on stigma related to HIV/AIDS, and 28 (97%) used information or education to reduce stigma. Intervention specification and description was uneven. Conclusion Implementation science could support the dissemination of stigma reduction interventions in LMICs, though usage to date has been limited. Theoretical frameworks and validated measures have not been used, key implementation outcomes like cost and sustainability have rarely been assessed, and intervention processes have not been presented in detail. Adapted frameworks, new measures, and increased LMIC-based implementation research capacity could promote the rigor of future stigma implementation research, helping the field deliver on the promise of stigma reduction interventions worldwide

    Coupled Effects of Hydrodynamics and Biogeochemistry on Zn Mobility and Speciation in Highly Contaminated Sediments

    No full text
    Porewater transport and diagenetic reactions strongly regulate the mobility of metals in sediments. We executed a series of laboratory experiments in Gust chamber mesocosms to study the effects of hydrodynamics and biogeochemical transformations on the mobility and speciation of Zn in contaminated sediments from Lake DePue, IL. X-ray absorption spectroscopy (XAS) indicated that the oxidation of surficial sediments promoted the formation of more mobile Zn species. Bulk chemical measurements of porewater, overlying water, and sediment also suggested that this process liberated aqueous metals to porewater and facilitated Zn efflux to the overlying water. In addition, sediment resuspension events increased the release of aqueous metals to both surficial porewater and the overlying water column. XAS analysis indicated that resuspension increased dissolution of Zn-sequestering mineral phases. These results show that both steady slow porewater transport and rapid episodic resuspension are important to the release of metal from fine-grained, low-permeability contaminated sediments. Thus, information on metals speciation and mobility under time-varying overlying flow conditions is essential to understanding the long-term behavior of metals in contaminated sediments

    Problems with Evidence Assessment in COVID-19 Health Policy Impact Evaluation (PEACHPIE): A systematic review of evidence strength

    No full text
    Introduction: The impact of policies on COVID-19 outcomes is one of the most important questions of our time. Unfortunately, there are substantial concerns about the strength and quality of the literature examining policy impacts. This study systematically assessed the currently published COVID-19 policy impact literature for a checklist of study design elements and methodological issues. Methods: We included studies that were primarily designed to estimate the quantitative impact of one or more implemented COVID-19 policies on direct SARS-CoV-2 and COVID-19 outcomes. After searching PubMed for peer-reviewed articles published on November 26 or earlier and screening, all studies were reviewed by three reviewers independently and in consensus. The review tool was based on review guidance for assessing COVID-19 health policy impact evaluation analyses, including first identifying the assumptions behind the methods used, followed by assessing graphical display of outcomes data, functional form for the outcomes, timing between policy and impact, concurrent changes to the outcomes, and an overall rating. Results: After 102 articles were identified as potentially meeting inclusion criteria, we identified 36 published articles that evaluated the quantitative impact of COVID-19 policies on direct COVID-19 outcomes. The majority (n=23/36) of studies in our sample examined the impact of stay-at-home requirements. Nine studies were set aside due to inappropriate study design (n=8 pre/post; n=1 cross-section), and 27 articles were given a full consensus assessment. 20/27 met criteria for graphical display of data, 5/27 for functional form, 19/27 for timing between policy implementation and impact, and only 3/27 for concurrent changes to the outcomes. Only 1/27 studies passed all of the above checks, and 4/27 were rated as overall appropriate. Including the 9 studies set aside, we found that only four (or by a stricter standard, only one) of the 36 identified published and peer-reviewed health policy impact evaluation studies passed a set of key design checks for identifying the causal impact of policies on COVID-19 outcomes. Discussion: The current literature directly evaluating the impact of COVID-19 policies largely fails to meet key design criteria for useful inference. This may be partially due to the circumstances for evaluation being particularly difficult, as well as a context with desire for rapid publication, the importance of the topic, and weak peer review processes. Importantly, weak evidence is non-informative and does not indicate how effective these policies were on COVID-19 outcomes

    Problems with evidence assessment in COVID-19 health policy impact evaluation: a systematic review of study design and evidence strength

    No full text
    INTRODUCTION: Assessing the impact of COVID-19 policy is critical for informing future policies. However, there are concerns about the overall strength of COVID-19 impact evaluation studies given the circumstances for evaluation and concerns about the publication environment. METHODS: We included studies that were primarily designed to estimate the quantitative impact of one or more implemented COVID-19 policies on direct SARS-CoV-2 and COVID-19 outcomes. After searching PubMed for peer-reviewed articles published on 26 November 2020 or earlier and screening, all studies were reviewed by three reviewers first independently and then to consensus. The review tool was based on previously developed and released review guidance for COVID-19 policy impact evaluation. RESULTS: After 102 articles were identified as potentially meeting inclusion criteria, we identified 36 published articles that evaluated the quantitative impact of COVID-19 policies on direct COVID-19 outcomes. Nine studies were set aside because the study design was considered inappropriate for COVID-19 policy impact evaluation (n=8 pre/post; n=1 cross-sectional), and 27 articles were given a full consensus assessment. 20/27 met criteria for graphical display of data, 5/27 for functional form, 19/27 for timing between policy implementation and impact, and only 3/27 for concurrent changes to the outcomes. Only 4/27 were rated as overall appropriate. Including the 9 studies set aside, reviewers found that only four of the 36 identified published and peer-reviewed health policy impact evaluation studies passed a set of key design checks for identifying the causal impact of policies on COVID-19 outcomes. DISCUSSION: The reviewed literature directly evaluating the impact of COVID-19 policies largely failed to meet key design criteria for inference of sufficient rigour to be actionable by policy-makers. More reliable evidence review is needed to both identify and produce policy-actionable evidence, alongside the recognition that actionable evidence is often unlikely to be feasible
    corecore