454 research outputs found

    The Disk and Dark Halo Mass of the Barred Galaxy NGC 4123. I. Observations

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    The non-circular streaming motions in barred galaxies are sensitive to the mass of the bar and can be used to lift the degeneracy between disk and dark matter halo encountered when fitting axisymmetric rotation curves of disk galaxies. In this paper, we present photometric and kinematic observations of NGC 4123, a barred galaxy of modest size (V_rot = 130 km/sec, L = 0.7 L_*), which reveal strong non-circular motions. The bar has straight dust lanes and an inner Lindblad resonance. The disk of NGC 4123 has no sign of truncation out to 10 scale lengths, and star-forming regions are found well outside R_25. A Fabry-Perot H-alpha velocity field shows velocity jumps of >100 km/sec at the location of the dust lanes within the bar, indicating shocks in the gas flow. VLA observations yield the velocity field of the H I disk. Axisymmetric mass models yield good fits to the rotation curve outside the bar regionfor disk I-band M/L of 2.25 or less, and dark halos with either isothermal or power-law profiles can fit the data well. In a companion paper, we model the full 2-D velocity field, including non-circular motions, to determine the stellar M/L and the mass of the dark halo.Comment: accepted by ApJ, 16 pages, 9 figures (1 color), uses emulateapj.sty, onecolfloat.st

    The properties of the Galactic bar implied by gas kinematics in the inner Milky Way

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    Longitude-velocity (l-V) diagrams of H I and CO gas in the inner Milky Way have long been known to be inconsistent with circular motion in an axisymmetric potential. Several lines of evidence suggest that the Galaxy is barred, and gas flow in a barred potential could be consistent with the observed ``forbidden'' velocities and other features in the data. We compare the H I observations to l-V diagrams synthesized from 2-D fluid dynamical simulations of gas flows in a family of barred potentials. The gas flow pattern is very sensitive to the parameters of the assumed potential, which allows us to discriminate among models. We present a model that reproduces the outer contour of the H I l-V diagram reasonably well; this model has a strong bar with a semimajor axis of 3.6 kpc, an axis ratio of approximately 3:1, an inner Lindblad resonance (ILR), and a pattern speed of 42 km/s/kpc, and matches the data best when viewed from 34\deg to the bar major axis. The behavior of the models, combined with the constraint that the shocks in the Milky Way bar should resemble those in external barred galaxies, leads us to conclude that wide ranges of parameter space are incompatible with the observations. In particular we suggest that the bar must be fairly strong, must have an ILR, and cannot be too end-on, with the bar major axis at 35\deg +/- 5\deg to the line of sight. The H I data exhibit larger forbidden velocities over a wider longitude range than are seen in molecular gas; this important difference is the reason our favored model differs so significantly from other recently proposed models.Comment: 23 pages, 14 figures, 1 table, uses emulateapj and psfig, 640 kb. Submitted to Ap

    Correlation of Adherence to the 2012 Infectious Diseases Society of America Practice Guidelines with Patient Outcomes in the Treatment of Diabetic Foot Infections in an Outpatient Parenteral Antimicrobial Programme

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    Aim To evaluate adherence to the 2012 Infectious Diseases Society of America practice guidelines for the management of patients with diabetic foot infections and to determine an association between adherence and clinical outcome. Methods A retrospective chart review was performed to evaluate the management and clinical outcomes of patients with diabetic foot infections treated with outpatient parenteral antimicrobial therapy between 1 January 2011 and 30 June 2012 at Wishard Health Services/Eskenazi Health. Adherence to individual Infectious Diseases Society of America diabetic foot infection treatment guideline recommendations was measured, and then assessed in relation to clinical outcome. Results A total of 57 patients (61% male, mean age 54 years) with moderate to severe diabetic foot infection met the inclusion criteria. None of the treatment courses of these patients adhered to all the Infectious Diseases Society of America guideline recommendations. The recommendations most frequently adhered to were consultation of appropriate multidisciplinary teams (n=54, 94.7%) and performance of diagnostic imaging (n=52, 89.5%). The recommendations least frequently adhered to were diabetic foot wound classification scoring on admission (n=0, 0%), appropriate culture acquisition (n=12, 21.2%), surgical intervention when indicated (n=32, 46.2%) and appropriate empiric antibiotic selection (n=34, 59.7%). Of 56 patients, 52 (92.9%) experienced clinical cure at the end of outpatient parenteral antimicrobial therapy compared with 34 of 53 patients (64%) at 6 months after the completion of therapy. Adherence to individual guidelines was not associated with clinical outcome. Patients who experienced treatment failure were more likely to have severe diabetic foot infection or peripheral neuropathy. Conclusions Adherence to the Infectious Diseases Society of America diabetic foot infection guideline recommendations was found to be suboptimal in the present study. The effect of adhering to individual Infectious Diseases Society of America diabetic foot infection recommendations on clinical outcome needs to be investigated

    Trauma, stressful life events and depression predict HIV-related fatigue

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    Despite the fact that fatigue is a common and debilitating symptom among HIV-infected persons, we know little about the predictors of fatigue in this population. The goal of this cross-sectional study was to examine the effects of early childhood trauma, recent stressful life events and depression on intensity and impairment of fatigue in HIV, over and above demographic factors and clinical characteristics. We studied 128 HIV-infected men and women from one southern state. The median number of childhood traumatic events was two and participants tended to have at least one moderate recent stressful event. Multiple regression findings showed that patients with less income, more childhood trauma, more recent stressful events and more depressive symptoms had greater fatigue intensity and fatigue-related impairment in daily functioning. Recent stresses were a more powerful predictor of fatigue than childhood trauma. None of the disease-related measures (e.g. CD4, viral load, antiretroviral medication) predicted fatigue. Although stress and trauma have been related to fatigue in other populations, this is the first study to examine the effects of traumatic and recent stressful life events on fatigue in an HIV-infected sample

    Longitudinal patterns of unmet need for contraception among women living with HIV on antiretroviral therapy in South Africa

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    Objectives: Fertility intentions and contraceptive use are often not assessed in the context of clinical HIV care, representing a possible programming gap if women's family planning needs change over time. We aimed to identify longitudinal patterns of unmet need for contraception over a 12-month period among women living with HIV taking antiretroviral therapy (ART). Study design: 850 non-pregnant, HIV-positive women aged 18-35 on or initiating ART in Johannesburg, South Africa, were enrolled into a prospective cohort study in 2009-2010. Fertility intentions and contraceptive use were assessed during routine HIV care visits via an interviewer-administered questionnaire, and women were referred for on-site contraceptive counseling. We used group-based trajectory modeling to identify patterns of unmet need for contraception over 12 months, first in the entire population and then in a subset of recent ART initiators. Results: In the full population we identified four patterns of unmet need for contraception over one year. Half of the enrolled women were predicted to have a consistently high probability of unmet need, 22.9% a consistently low probability, 16.7% a decreasing probability, and 10.4% an increasing probability over time. Contraceptive method discontinuation and rapidly changing fertility intentions were the primary drivers of changing (increasing or decreasing) unmet need over follow-up. Results were similar in recent ART initiators. Conclusions: Half of women were estimated to have a high probability of unmet need that persisted over time, and more than a quarter were estimated to experience patterns of changing unmet need over 12 months. Family planning needs should be assessed more regularly in HIV-positive women to prevent unintended pregnancies and support safer conception among women trying to conceive

    Trajectories of fertility intentions among women living with HIV in South Africa

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    Fertility intentions are thought to be dynamic among women of reproductive age, yet few studies have assessed fertility intentions over time among women with HIV. We examine temporal patterns of fertility intentions in women with HIV to assess the extent to which fertility intentions–and the corresponding need for safer conception and judicious antiretroviral therapy (ART) regimen selection–vary over time. 850 non-pregnant HIV-positive women aged 18–35 on or being initiated onto ART in Johannesburg, South Africa were enrolled into a prospective cohort study (2009–2010). Fertility intentions were assessed at enrollment and at 30-day intervals via an interviewer-administered questionnaire. We used group-based trajectory modelling to identify longitudinal patterns of fertility intentions over 12 months. We identified four patterns of fertility intentions, which we labelled “consistently low” (representing ∌60% of the population), “low and increasing” (∌23%), “high and increasing” (∌12%), and “high and decreasing” (∌5%). Our findings suggest that a single family-planning assessment at one time point is insufficient to fully identify and meet the reproductive needs of women with HIV. As HIV testing and treatment evolve in South Africa, routine screening for fertility intentions can offer important opportunities to optimize HIV treatment, prevention, and maternal and child health

    Trauma history and depression predict incomplete adherence to antiretroviral therapies in a low income country.

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    As antiretroviral therapy (ART) for HIV becomes increasingly available in low and middle income countries (LMICs), understanding reasons for lack of adherence is critical to stemming the tide of infections and improving health. Understanding the effect of psychosocial experiences and mental health symptomatology on ART adherence can help maximize the benefit of expanded ART programs by indicating types of services, which could be offered in combination with HIV care. The Coping with HIV/AIDS in Tanzania (CHAT) study is a longitudinal cohort study in the Kilimanjaro Region that included randomly selected HIV-infected (HIV+) participants from two local hospital-based HIV clinics and four free-standing voluntary HIV counselling and testing sites. Baseline data were collected in 2008 and 2009; this paper used data from 36 month follow-up interviews (N = 468). Regression analyses were used to predict factors associated with incomplete self-reported adherence to ART. INCOMPLETE ART ADHERENCE WAS SIGNIFICANTLY MORE LIKELY TO BE REPORTED AMONGST PARTICIPANTS WHO EXPERIENCED A GREATER NUMBER OF CHILDHOOD TRAUMATIC EVENTS: sexual abuse prior to puberty and the death in childhood of an immediate family member not from suicide or homicide were significantly more likely in the non-adherent group and other negative childhood events trended toward being more likely. Those with incomplete adherence had higher depressive symptom severity and post-traumatic stress disorder (PTSD). In multivariable analyses, childhood trauma, depression, and financial sacrifice remained associated with incomplete adherence.\ud This is the first study to examine the effect of childhood trauma, depression and PTSD on HIV medication adherence in a low income country facing a significant burden of HIV. Allocating spending on HIV/AIDS toward integrating mental health services with HIV care is essential to the creation of systems that enhance medication adherence and maximize the potential of expanded antiretroviral access to improve health and reduce new infections

    Socioecological Factors Related to Hazardous Alcohol use among Female Sex Workers in Lilongwe, Malawi: A Mixed Methods Study

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    Background: Alcohol use is pervasive among female sex workers (FSW) placing them at increased risk of violence and sexual risk behaviors. FSW often live and work where alcohol is highly normative. Objective: To understand the socioecological influences on hazardous alcohol use among FSW in Malawi. Methods: In 2014, 200 FSW identified through venue-based sampling in Lilongwe, Malawi, completed a quantitative behavioral survey, with a sub-sample participating in qualitative interviews. Multivariable log-binomial regression was used to identify associations between hazardous alcohol use (AUDIT score ≄ 7) and time in sex work, clients per week, unprotected sex, alcohol use with clients, and living environment. Qualitative interviews enhanced findings from quantitative data and identify emergent themes around socioecological influences on alcohol use. Results: Over 50% reported hazardous alcohol use and lived in an alcohol-serving venue. Hazardous alcohol use was associated with sex work duration of ≄2 years (aPR: 1.30; 95%CI: 1.02,1.65) and alcohol use at last sex with a client (aPR: 1.29; 95%CI: 1.06,1.57). FSW perceived alcohol as a facilitator for sex work by reducing inhibitions and attracting clients, but acknowledged alcohol leads to violence and/or unprotected sex. Despite these risks and a motivation to reduce use, FSW feared that refusing to drink would be tantamount to turning away clients. Conclusions: Although FSW recognized alcohol-related risks, the norms and power dynamics of sex work perpetuated hazardous alcohol use. Multilevel interventions are needed to collectively change norms around drinking and sex work that will enable FSW to reduce alcohol consumption when engaging in their work

    The Chandra ACIS Survey of M33 (ChASeM33): The final source catalog

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    This study presents the final source catalog of the Chandra ACIS Survey of M33 (ChASeM33). With a total exposure time of 1.4 Ms, ChASeM33 covers ~70% of the D25 isophote (R\approx4kpc) of M33 and provides the deepest, most complete, and detailed look at a spiral galaxy in X-rays. The source catalog includes 662 sources, reaches a limiting unabsorbed luminosity of ~2.4x10^(34) erg/s in the 0.35-8.0keV energy band, and contains source positions, source net counts, fluxes and significances in several energy bands, and information on source variability. The analysis challenges posed by ChASeM33 and the techniques adopted to address these challenges are discussed. To constrain the nature of the detected X-ray source, hardness ratios were constructed and spectra were fit for 254 sources, followup MMT spectra of 116 sources were acquired, and cross-correlations with previous X-ray catalogs and other multi-wavelength data were generated. Based on this effort, 183 of the 662 ChASeM33 sources could be identified. Finally, the luminosity function for the detected point sources as well as the one for the X-ray binaries in M33 is presented. The luminosity functions in the soft band (0.5-2.0 keV) and the hard band (2.0-8.0 keV) have a limiting luminosity at the 90% completeness limit of 4.0x10^(34) erg/s and 1.6x10^(35) erg/s (for D=817kpc), respectively, which is significantly lower than what was reported by previous X-ray binary population studies in galaxies more distant than M33. The resulting distribution is consistent with a dominant population of high mass X-ray binaries as would be expected for M33.Comment: 186 pages, 11 figures, 10 tables. Accepted for publication in the ApJS. For a high resolution version of the paper, see http://hea-www.harvard.edu/vlp_m33_public
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