45 research outputs found
How to Improve a Medication-Assisted Treatment Program for Opioid Use Disorder: First, Look at the Evidence
The prevalence of Opioid Use Disorder (OUD) in the United States has been described as an epidemic, and rural areas have been affected in particular. A treatment paradigm called Medication-Assisted Treatment (MAT) has been demonstrated to be effective at treating OUD, and more and more rural, primary care clinics are establishing MAT programs. One such clinic is Hudson Headwaters Health Network, a FQHC in Upstate New York. I wrote a literature review and distributed it to staff involved in MAT program design, and I also wrote a practical evidence guide for MAT providers. Providers completed a survey assessing the evidence guide.https://scholarworks.uvm.edu/fmclerk/1513/thumbnail.jp
Role of the Dental Community in HPV Vaccination Promotion
Introduction. With increasing awareness that human papillomavirus (HPV) can cause oropharyngeal cancer (OPC), dental providers may play an important role in promoting HPV vaccination and preventing cancer. Our goal was to assess knowledge and current HPV vaccine counseling practices among Vermont dentists and dental hygienists to identify potential targets for state-level interventions to increase vaccine coverage.
Methods. We developed a survey to assess knowledge, beliefs, practices and barriers regarding HPV vaccination, and distributed it via email to practicing Vermont dentists and dental hygienists. Free responses were analyzed using a coding framework generated from three key informant interviews.
Results. 90% of providers believe it is important for them to play an “active role” in their patients’ general medical care, yet only 50% believe it is their responsibility to recommend HPV vaccine. Only 50% feel knowledgeable enough to recommend the vaccine. 78.6% of providers rarely discuss HPV vaccination with their age-appropriate patients, and 82% rarely recommend the vaccine. When asked to name the biggest barrier against recommending vaccination, providers named the following factors most frequently: “not responsibility of dental provider” (27%); lack of confidence in knowledge (19%); time constraints (14%); and parent philosophical/religious opposition (11%).
Discussion. Because dentists and dental hygienists care for a broad pediatric population across the state, dental communities may be poised to play an expanded role in Vermont’s efforts to improve its HPV vaccination coverage. Our study identifies several potential areas for provider-focused interventions, which include educating providers about the HPV vaccine and reducing significant barriers against recommending.https://scholarworks.uvm.edu/comphp_gallery/1266/thumbnail.jp
Long-Term Profile Variability in Active Galactic Nuclei with Double-Peaked Balmer Emission Lines
An increasing number of Active Galactic Nuclei (AGNs) exhibit broad,
double-peaked Balmer emission lines,which represent some of the best evidence
for the existence of relatively large-scale accretion disks in AGNs. A set of
20 double-peaked emitters have been monitored for nearly a decade in order to
observe long-term variations in the profiles of the double-peaked Balmer lines.
Variations generally occur on timescales of years, and are attributed to
physical changes in the accretion disk. Here we characterize the variability of
a subset of seven double-peaked emitters in a model independent way. We find
that variability is caused primarily by the presence of one or more discrete
"lumps" of excess emission; over a timescale of a year (and sometimes less)
these lumps change in amplitude and shape, but the projected velocity of these
lumps changes over much longer timescales (several years). We also find that
all of the objects exhibit red peaks that are stronger than the blue peak at
some epochs and/or blueshifts in the overall profile, contrary to the
expectations for a simple, circular accretion disk model, thus emphasizing the
need for asymmetries in the accretion disk. Comparisons with two simple models,
an elliptical accretion disk and a circular disk with a spiral arm, are unable
to reproduce all aspects of the observed variability, although both account for
some of the observed behaviors. Three of the seven objects have robust
estimates of the black hole masses. For these objects the observed variability
timescale is consistent with the expected precession timescale for a spiral
arm, but incompatible with that of an elliptical accretion disk. We suggest
that with the simple modification of allowing the spiral arm to be fragmented,
many of the observed variability patterns could be reproduced.Comment: 74 pages, 4 tables, 35 figure
The Physical Conditions of the Intrinsic N V Narrow Absorption Line Systems of Three Quasars
We employ detailed photoionization models to infer the physical conditions of
intrinsic narrow absorption line systems found in high resolution spectra of
three quasars at z=2.6-3.0. We focus on a family of intrinsic absorbers
characterized by N V lines that are strong relative to the Ly-alpha lines. The
inferred physical conditions are similar for the three intrinsic N V absorbers,
with metallicities greater than 10 times the solar value (assuming a solar
abundance pattern), and with high ionization parameters (log U ~ 0). Thus, we
conclude that the unusual strength of the N V lines results from a combination
of partial coverage, a high ionization state, and high metallicity. We consider
whether dilution of the absorption lines by flux from the broad-emission line
region can lead us to overestimate the metallicities and we find that this is
an unlikely possibility. The high abundances that we infer are not surprising
in the context of scenarios in which metal enrichment takes place very early on
in massive galaxies. We estimate that the mass outflow rate in the absorbing
gas (which is likely to have a filamentary structure) is less than a few solar
masses per year under the most optimistic assumptions, although it may be
embedded in a much hotter, more massive outflow.Comment: To appear in the Astrophysical Journa
Broad-line Balmer Decrements in Blue Active Galactic Nuclei
We have investigated the broad-line Balmer decrements (Halpha/Hbeta) for a
large, homogeneous sample of Seyfert 1 galaxies and QSOs using spectroscopic
data obtained in the Sloan Digital Sky Survey. The sample, drawn from the
Fourth Data Release, comprises 446 low redshift (z < 0.35) active galactic
nuclei (AGN) that have blue optical continua as indicated by the spectral
slopes in order to minimize the effect of dust extinction. We find that (i) the
distribution of the intrinsic broad-line Halpha/Hbeta ratio can be well
described by log-Gaussian, with a peak at Halpha/Hbeta=3.06 and a standard
deviation of about 0.03 dex only; (ii) the Balmer decrement does not correlate
with AGN properties such as luminosity, accretion rate, and continuum slope,
etc.; (iii) on average, the Balmer decrements are found to be only slightly
larger in radio-loud sources (3.37) and sources having double-peaked
emission-line profiles (3.27) compared to the rest of the sample. We therefore
suggest that the broad-line Halpha/Hbeta ratio can be used as a good indicator
for dust extinction in the AGN broad-line region; this is especially true for
radio-quiet AGN with regular emission-line profiles, which constitute the vast
majority of the AGN population.Comment: To appear in MNRAS. The data and the fitted parameters for the
decomposed spectral components (continuum, FeII and other emission lines) of
the 446 blue AGNs are available at
http://staff.ustc.edu.cn/~xbdong/Data_Release/blueAGN_DR4
The mass-metallicity relation of SDSS quasars
Active galactic nuclei (AGNs) are characterized by a clear correlation
between luminosity and metallicity (L_AGN-Z_AGN relation). The origin of this
correlation is not clear. It may result from a relation between the black hole
mass (M_BH) and metallicity, or from a relation between the accretion rate
(L/L_Edd) and metallicity. To investigate the origin of the L_AGN-Z_AGN
relation, we use optical spectra of 2383 quasars at 2.3 < z < 3.0 from the
Sloan Digital Sky Survey. By using this data set, we have constructed composite
spectra of 33 subsamples in intervals of both M_BH and L/L_Edd. From these
composite spectra we measure emission-line flux ratios that are sensitive to
the metallicity of the broad line region (BLR); specifically, NV/CIV, NV/HeII,
(SiIV+OIV])/CIV, and AlIII/CIV. We find that there is a significant correlation
between M_BH and Z_BLR as inferred from all four metallicity-sensitive
emission-line flux ratios. This result strongly suggests that the observed
L_AGN-Z_AGN relation is mostly a consequence of the M_BH-Z_AGN relation. The
relation between M_BH and Z_BLR is likely a consequence of both the M_BH-M_bul
relation and of the mass-metallicity relation in the host galaxy. We also find
that L/L_Edd correlates with the emission line flux ratios involving NV (more
specifically, NV/CIV and NV/HeII), while it does not correlate with the other
two metallicity sensitive emission line flux ratios, i.e., (SiIV+OIV])/CIV and
AlIII/CIV. These correlations indicate that the emission-line flux ratios
involving NV depend on both metallicity and relative abundance of nitrogen. We
suggest that the relation between L/L_Edd and those line ratios involving
nitrogen, is caused by a delay of the black hole accretion rate relative to the
onset of nuclear star formation of about 10^8 years, which is the timescale
required for the nitrogen enrichment.Comment: Accepted for publication in A&A, 16 pages, 6 figure
CIV Emission and the Ultraviolet through X-ray Spectral Energy Distribution of Radio-Quiet Quasars
In the restframe UV, two of the parameters that best characterize the range
of emission-line properties in quasar broad emission-line regions are the
equivalent width and the blueshift of the CIV line relative to the quasar rest
frame. We explore the connection between these emission-line properties and the
UV through X-ray spectral energy distribution (SED) for radio-quiet (RQ)
quasars. Our sample consists of a heterogeneous compilation of 406 quasars from
the Sloan Digital Sky Survey and Palomar-Green survey that have well-measured
CIV emission-line and X-ray properties (including 164 objects with measured
Gamma). We find that RQ quasars with both strong CIV emission and small CIV
blueshifts can be classified as "hard-spectrum" sources that are (relatively)
strong in the X-ray as compared to the UV. On the other hand, RQ quasars with
both weak CIV emission and large CIV blueshifts are instead "soft-spectrum"
sources that are (relatively) weak in the X-ray as compared to the UV. This
work helps to further bridge optical/soft X-ray "Eigenvector 1" relationships
to the UV and hard X-ray. Based on these findings, we argue that future work
should consider systematic errors in bolometric corrections (and thus accretion
rates) that are derived from a single mean SED. Detailed analysis of the CIV
emission line may allow for SED-dependent corrections to these quantities.Comment: AJ, in press; 39 pages, 11 figures, 3 table
What controls the Fe II strength in active galactic nuclei?
We used a large, homogeneous sample of 4178 z <= 0.8 Seyfert 1 galaxies and
QSOs selected from the Sloan Digital Sky Survey to investigate the strength of
Fe II emission and its correlation with other emission lines and physical
parameters of active galactic nuclei. We find that the strongest correlations
of almost all the emission-line intensity ratios and equivalent widths (EWs)
are with the Eddington ratio (L/L_{Edd}), rather than with the continuum
luminosity at 5100\AA\ (L_{5100}) or black hole mass (M_{BH}); the only
exception is the EW of ultraviolet Fe II emission, which does not correlate at
all with broad-line width, L_{5100}, M_{BH}, or L/L_{Edd}. By contrast, the
intensity ratios of both the ultraviolet and optical Fe II emission to Mg II
\lambda 2800 correlate quite strongly with L/L_{Edd}. Interestingly, among all
the emission lines in the near-UV and optical, the EW of narrow optical Fe II
emission has the strongest correlation with L/L_{Edd}. We suggest that the
variation of the emission-line strength in active galaxies is regulated by
L/L_{Edd} because it governs the global distribution of the column density of
the clouds gravitationally bound in the line-emitting region, as well as its
overall gas supply. The systematic dependence on L/L_{Edd} must be corrected
when using the FeII/MgII intensity ratio as a measure of the Fe/Mg abundance
ratio to study the history of chemical evolution in QSO environments.Comment: V3: to match the ApJ version scheduled to publish in June 2011.
Electronic tables are also available at
http://staff.ustc.edu.cn/~xbdong/Data_Release/ell_effect
Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study
Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research