2,219 research outputs found
UGC 3995: A Close Pair of Spiral Galaxies
UGC 3995 is a close pair of spiral galaxies whose eastern component hosts a
Seyfert 2 nucleus. We present a detailed analysis of this system using long
slit spectroscopy and narrow (\ha + \nii) as well as broad band (B, R) imaging
and an archive WFPC2 image. The component galaxies reveal surprisingly small
signs of interaction considering their spatial proximity and almost identical
recession velocities, as the bright filament is probably an optical illusion
due to the superposition of the bar of the Seyfert galaxy and of the spiral
arms of the companion. The broad band morphology, a B--R color map, and a
continuum-subtracted \ha + \nii image demonstrate that the western component
UGC 3995B is in front of the Seyfert-hosting component UGC 3995A, partly
obscuring its western side. The small radial velocity difference leaves the
relative motion of the two galaxies largely unconstrained. The observed lack of
major tidal deformations, along with some morphological peculiarities, suggests
that the galaxies are proximate in space but may have recently approached each
other on the plane of the sky. The geometry of the system and the radial
velocity curve at P. A. = 106 suggest that the encounter may be retrograde or,
alternatively, prograde before perigalacticon. The partial overlap of the two
galaxies allows us to estimate the optical thickness of the disk of component
B. We derive an extinction = 0.18 visual magnitudes in the infra-arms parts of
the foreground galaxy disk, and >= 1-1.5 visual magnitudes in correspondence of
the spiral arms.Comment: Accepted for publication in the Astronomical Journal (June 1999
issue
The interplay between voluntary vaccination and reduction of risky behavior: a general behavior-implicit SIR model for vaccine preventable infections
The onset in the last 15 years of behavioral epidemiology has opened many new avenues for epidemiological modelers. In this manuscript we first review two classes of behavioral epidemiology models for vaccine preventable diseases, namely behaviour-implicit SIR models with prevalence-dependent vaccination (at birth and among older individuals), and prevalence-dependent contact rate.
Subsequently, we briefly propose a general framework of behaviorâdependent nonlinear and linear Forces of Infection (FoI) valid for a vast family of infectious diseases, and including delays and âepidemic memoryâ effects.
Finally and mainly, we develop a new general behavioral SIR model. This model combines the two aforementioned types of behavioral phenomena, previously considered only separately, into a single unified model for behavioral responses. The resulting model allows to develop a general phenomenological theory of the effects of behavioral responses within SIR models for endemic infections. In particular, the model allows to complete the picture about the complicate interplay between different behavioral responses acting on different epidemiological parameters in triggering sustained oscillations of vaccine coverage, risky behavior, and infection prevalence
Aids and surgery
HIV constitutes one of the most difficult challenges facing the healthcare profession today. It is estimated that HIV infects over 40 million people in the world and 14 million have died from the disease so far. The objective of the study was to evaluate the outcome of treatment of HIV-related surgical conditions, estimating the morbidity and mortality of surgical intervention cross infection risks to surgical equipes and analysing preventive strategies to HIV perioperative transmission
Globular Clusters in Dense Clusters of Galaxies
Deep imaging data from the Keck II telescope are employed to study the
globular cluster (GC) populations in the cores of six rich Abell clusters. The
sample includes A754, A1644, A2124, A2147, A2151, and A2152, and spans the
redshift range z = 0.035-0.066. The clusters also range in morphology from
spiral-rich, irregular systems to centrally concentrated cD clusters rich in
early-type galaxies. Globular cluster specific frequencies S_N and luminosity
function dispersions are measured for a total of 9 galaxies in six central
fields. The measured values of S_N for the six brightest cluster galaxies
(BCGs) are all higher than typical values for giant ellipticals, in accord with
the known S_N-density correlations. The three non-BCGs analyzed also have
elevated values of S_N, confirming that central location is a primary factor.
The number of GCs per unit mass for these fields are consistent with those
found in an earlier sample, giving further evidence that GC number scales with
mass and that the S_N variations are due to a deficit of halo light, i.e., S_N
reflects mass-to-light ratio.
The discussion builds on an earlier suggestion that the GCs (both metal rich
and metal poor) around the central cluster galaxies were assembled at early
times, and that star formation halted prematurely in the central galaxies at
the epoch of cluster collapse. This is consistent with recent simulations of
BCG/cluster formation. The subsequent addition of luminous material through
cluster dynamical evolution can cause S_N to decrease, and we may be seeing the
first evidence of this. Finally, the GC luminosity function measurements are
used to constrain the relative distances of the three clusters that make up the
Hercules supercluster.Comment: Uses emulateapj.sty (included); 17 pages with 9 included PostScript
figures. Figures 1-6 are separate GIF images (so 15 figures total) available
from http://astro.caltech.edu/~jpb/clusters -- the full PostScript version of
the paper (20 pages; 2.2 Mb compressed) incorporating Figures 1-6 can also be
grabbed from this URL. Accepted for publication in A
The role of dark matter in the galaxy mass-size relationship
The observed relationship between stellar mass and effective radius for early
type galaxies, pointed out by many authors, is interpreted in the context of
Clausius' virial maximum theory. In this view, it is strongly underlined that
the key of the above mentioned correlation is owing to the presence of a deep
link between cosmology and the existence of the galaxy Fundamental Plane. Then
the ultimate meaning is: understanding visible mass - size correlation and/or
Fundamental Plane means understanding how galaxies form. The mass - size
relationship involves baryon (mainly stellar) mass and its typical dimension
related to the light, but it gets memory of the cosmological mass variance at
the equivalence epoch. The reason is that the baryonic component virializes by
sharing virial energy in about equal amount between baryons and dark matter,
this sharing depending, in turn, on the steepness of the dark matter
distribution. The general strategy consists in using the two-component tensor
virial theorem for determining the virialized baryonic configurations. A King
and a Zhao density profile are assumed for the inner baryonic and the outer
dark matter component, respectively, at the end of the relaxation phase. All
the considerations are restricted to spherical symmetry for simplicity. The
effect of changing the dark-to-baryon mass ratio, m, is investigated inside a
LambdaCDM scenario. A theoretical mass - size relation is expressed for the
baryonic component, which fits fairly well to the data from a recently studied
galaxy sample. Finally, the play of intrinsic dispersion on the mass ratio, m,
is discussed in the light of the cusp/core problem and some consequences are
speculated about the existence of a limit, m_l, expected by the theory.Comment: 36 pages, 8 figures (Accepted for publication in New Astronomy
Incident and long-term opioid therapy among patients with psychiatric conditions and medications: a national study of commercial health care claims
There is growing evidence that opioid prescribing in the United States follows a pattern in which patients who are at the highest risk of adverse outcomes from opioids are more likely to receive long-term opioid therapy. These patients include, in particular, those with substance use disorders (SUDs) and other psychiatric conditions. This study examined health insurance claims among 10,311,961 patients who filled prescriptions for opioids. Specifically, we evaluated how opioid receipt differed among patients with and without a wide range of preexisting psychiatric and behavioral conditions (ie, opioid and nonopioid SUDs, suicide attempts or other self-injury, motor vehicle crashes, and depressive, anxiety, and sleep disorders) and psychoactive medications (ie, antidepressants, benzodiazepines, hypnotics, mood stabilizers, antipsychotics, and medications used for SUD, tobacco cessation, and attention-deficit/hyperactivity disorder). Relative to those without, patients with all assessed psychiatric conditions and medications had modestly greater odds of subsequently filling prescriptions for opioids and, in particular, substantially greater risk of long-term opioid receipt. Increases in risk for long-term opioid receipt in adjusted Cox regressions ranged from approximately 1.5-fold for prior attention-deficit/hyperactivity disorder medication prescriptions (hazard ratio [HR] = 1.53; 95% confidence interval [CI], 1.48-1.58) to approximately 3-fold for prior nonopioid SUD diagnoses (HR = 3.15; 95% CI, 3.06-3.24) and nearly 9-fold for prior opioid use disorder diagnoses (HR = 8.70; 95% CI, 8.20-9.24). In sum, we found evidence of greater opioid receipt among commercially insured patients with a breadth of psychiatric conditions. Future studies assessing behavioral outcomes associated with opioid prescribing should consider preexisting psychiatric conditions
Boxy/peanut/X bulges, barlenses and the thick part of galactic bars: What are they and how did they form?
Bars have a complex three-dimensional shape. In particular their inner part
is vertically much thicker than the parts further out. Viewed edge-on, the
thick part of the bar is what is commonly known as a boxy-, peanut- or X- bulge
and viewed face-on it is referred to as a barlens. These components are due to
disc and bar instabilities and are composed of disc material. I review here
their formation, evolution and dynamics, using simulations, orbital structure
theory and comparisons to observations.Comment: 21 pages, 7 figures, invited review to appear in "Galactic Bulges",
E. Laurikainen, R. Peletier, D. Gadotti, (eds.), Springe
Association of Mental Health Conditions and Treatments With Long-term Opioid Analgesic Receipt Among Adolescents
Importance:
Adults with mental health conditions are more likely than those without to receive long-term opioid therapy. Less is known about opioid therapy among adolescents, especially those with mental health conditions.
Objective:
To examine associations between preexisting mental health conditions and treatments and initiation of any opioid and long-term opioid therapy among adolescents.
Design, Setting, and Participants:
A cohort of 1âŻ224âŻ520 incident opioid recipients without cancer diagnoses aged 14 to 18 years at first receipt was extracted from nationwide commercial health care claims data from January 1, 2003, to December 31, 2014. Analysis was conducted from August 19, 2016, to November 16, 2017. Associations between preexisting mental health conditions and treatments and any opioid receipt were examined by comparing recipients with nonrecipients matched on sex, calendar year and years of age of first enrollment, and months of enrollment (prior to the index month for recipients, ever for nonrecipients). Associations between preexisting mental health conditions and treatments and subsequent long-term opioid therapy were examined among recipients with at least 6 months' follow-up using Cox proportional hazards regressions adjusted for demographics.
Exposures:
Mental health condition diagnoses and treatments recorded in inpatient, outpatient, and filled-prescription claims prior to opioid receipt.
Main Outcomes and Measures:
Opioid receipt, defined as any opioid analgesic prescription claim, and long-term opioid therapy, defined as more than 90 days' supply within a 6-month window having no gaps in supply of more than 32 days.
Results:
Of the 1âŻ224âŻ520 new opioid recipients included, the median age at first receipt was 17 years (interquartile range, 16-18 years), and 51.1% were female. Median follow-up after first receipt was 625 days (interquartile range, 255-1268 days). Adolescents with anxiety, mood, neurodevelopmental, sleep, and nonopioid substance use disorders and most mental health treatments were significantly more likely to receive any opioid (odds ratios from 1.13 [95% CI, 1.10-1.16] for nonopioid substance use disorders to 1.69 [95% CI, 1.58-1.81] for nonbenzodiazepine hypnotics). Among the 1âŻ000âŻ453 opioid recipients (81.7%) who had at least 6 months' follow-up, the cumulative incidence of long-term opioid therapy was 3.0 (95% CI, 2.8-3.1) per 1000 recipients within 3 years after first opioid receipt. All preexisting mental health conditions and treatments were strongly associated with higher rates of long-term opioid therapy (adjusted hazard ratios from 1.73 [95% CI 1.54-1.95] for attention-deficit/hyperactivity disorder to 8.90 [95% CI, 5.85-13.54] for opioid use disorder).
Conclusions and Relevance:
Commercially insured adolescents with many types of preexisting mental health conditions and treatments were modestly more likely to receive any opioid and were substantially more likely to subsequently transition to long-term opioid therapy relative to those without, although overall rates of long-term opioid therapy were low
Alcohol, Tobacco, and Other Drugs: Future Directions for Screening and Intervention in the Emergency Department
This article is a product of a breakout session on injury prevention from the 2009 Academic Emergency Medicine consensus conference on âPublic Health in the ED: Screening, Surveillance, and Intervention.â The emergency department (ED) is an important entry portal into the medical care system. Given the epidemiology of substance use among ED patients, the delivery of effective brief interventions (BIs) for alcohol, drug, and tobacco use in the ED has the potential to have a large public health impact. To date, the results of randomized controlled trials of interventional studies in the ED setting for substance use have been mixed in regard to alcohol and understudied in the area of tobacco and other drugs. As a result, there are more questions remaining than answered. The work group developed the following research recommendations that are essential for the field of screening and BI for alcohol, tobacco, and other drugs in the ED. 1) Screeningâdevelop and validate brief and practical screening instruments for ED patients and determine the optimal method for the administration of screening instruments. 2) Key components and delivery methods for interventionâconduct research on the effectiveness of screening, brief intervention, and referral to treatment (SBIRT) in the ED on outcomes (e.g., consumption, associated risk behaviors, and medical psychosocial consequences) including minimum dose needed, key components, optimal delivery method, interventions focused on multiple risk behaviors and tailored based on assessment, and strategies for addressing polysubstance use. 3) Effectiveness among patient subgroupsâconduct research to determine which patients are most likely to benefit from a BI for substance use, including research on moderators and mediators of intervention effectiveness, and examine special populations using culturally and developmentally appropriate interventions. 4) Referral strategiesâa) promote prospective effectiveness trials to test best strategies to facilitate referrals and access from the ED to preventive services, community resources, and substance abuse and mental health treatment; b) examine impact of available community services; c) examine the role of stigma of referral and follow-up; and d) examine alternatives to specialized treatment referral. 5) Translationâconduct translational and cost-effectiveness research of proven efficacious interventions, with attention to fidelity, to move ED SBIRT from research to practice.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78664/1/j.1553-2712.2009.00552.x.pd
Transapical off-pump echo-guided mitral valve repair with neochordae implantation mid-term outcomes
Background: The NeoChord echo-guided transapical beating heart repair is a promising early-stage
minimally invasive surgical procedure for degenerative mitral valve (MV) regurgitation (DMR) correction.
The technique has been improved since its inception following procedure standardization, patient selection
optimization, and learning curve stabilization. We hereby present the mid-term clinical results through three
years of our large single center experience.
Methods: All consecutive patients with severe symptomatic DMR due to prolapse or flail of one or both
mitral leaflets that underwent the NeoChord procedure between November 2013 and June 2019 were
included. Patients were categorized according to MV anatomy; Type A isolated central posterior leaflet
prolapse and/or flail, Type B posterior multi-segment prolapse and/or flail, Type C anterior and/or bi-leaflet
prolapse or flail, Type D paracommissural prolapse and/or flail and/or significant leaflet and/or annular
calcifications. Patients underwent clinical and echocardiographic follow-up at one, three, six, twelve months
and yearly thereafter. Clinical outcomes and the composite primary endpoint (patient success) were defined
according to Mitral Valve Academic Research Consortium (MVARC) criteria. Mitral regurgitation (MR)
severity was graded as absent, mild, moderate and severe according to American Society of Echocardiography
(ASE) and European Society of Cardiology (ESC) guidelines.
Results: Two hundred and three patients were included; median follow-up was 24 months [interquartile
range (IQR), 9â36]. Median age was 64 years (IQR, 54â74 years), median Society of Thoracic Surgeons
(STS) Predicted Risk of Mortality (PROM) was 0.60% (IQR, 0.32â1.44%). There were 106 Type A patients
(52.2%), 68 Type B (33.5%), 16 Type C (7.9%), and 13 Type D (6.4%). Kaplan-Meier estimate of survival
was 99.0%±0.7% at one and two years and 94.0%±2.9% at three years. At one-year follow-up patient success
was 91.2%±2.0% and 111 patients (74%) presented a residual MR mild or less (1+). At three-year follow-up
patient success was 81.2%±3.8% and 32 patients (64%) had a residual MR mild or less (1+). Patient success
was significantly different according to anatomical type (P=0.001). Echocardiographic analysis showed a
significant acute left ventricle and left atrial reverse remodeling that was maintained up to three years.
Conclusions: The NeoChord echo-guided transapical beating heart repair procedure demonstrated good
clinical outcomes and echocardiographic results up to three-year follow-up
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