203 research outputs found
Electron-Ion Recombination on Grains and Polycyclic Aromatic Hydrocarbons
With the high-resolution spectroscopy now available in the optical and
satellite UV, it is possible to determine the neutral/ionized column density
ratios for several different elements in a single cloud. Assuming ionization
equilibrium for each element, one can make several independent determinations
of the electron density. For the clouds for which such an analysis has been
carried out, these different estimates disagree by large factors, suggesting
that some process (or processes) besides photoionization and radiative
recombination might play an important role in the ionization balance. One
candidate process is collisions of ions with dust grains.
Making use of recent work quantifying the abundances of polycyclic aromatic
hydrocarbon molecules and other grains in the interstellar medium, as well as
recent models for grain charging, we estimate the grain-assisted ion
recombination rates for several astrophysically important elements. We find
that these rates are comparable to the rates for radiative recombination for
conditions typical of the cold neutral medium. Including grain-assisted ion
recombination in the ionization equilibrium analysis leads to increased
consistency in the various electron density estimates for the gas along the
line of sight to 23 Orionis. However, not all of the discrepancies can be
eliminated in this way; we speculate on some other processes that might play a
role. We also note that grain-assisted recombination of H+ and He+ leads to
significantly lower electron fractions than usually assumed for the cold
neutral medium.Comment: LaTeX(12 pages, 8 figures, uses emulateapj5.sty, apjfonts.sty);
submitted to ApJ; corrected typo
UV Absorption Lines from High-Velocity Gas in the Vela Supernova Remnant: New insights from STIS Echelle Observations of HD72089
The star HD72089 is located behind the Vela supernova remnant and shows a
complex array of high and low velocity interstellar absorption features arising
from shocked clouds. A spectrum of this star was recorded over the wavelength
range 1196.4 to 1397.2 Angstroms at a resolving power lambda/Delta lambda =
110,000 and signal-to-noise ratio of 32 by STIS on the Hubble Space Telescope.
We have identified 7 narrow components of C I and have measured their relative
populations in excited fine-structure levels. Broader features at heliocentric
velocities ranging from -70 to +130 km/s are seen in C II, N I, O I, Si II, S
II and Ni II. In the high-velocity components, the unusually low abundances of
N I and O I, relative to S II and Si II, suggest that these elements may be
preferentially ionized to higher stages by radiation from hot gas immediately
behind the shock fronts.Comment: 11 pages, 2 figures, Latex. Submitted for the special HST ERO issue
of the Astrophysical Journal Letter
The Grizzly, October 2, 1981
Homecoming Celebration Takes on New Meaning • Previously Idle Appeals Procedure Finally Tested • Faculty Member\u27s Dismissal Creates Unrest • President Calls School Start \u27One of the Best Ever\u27 • Comment: I Thought This Was College • Parent Involvement Sought in Planning for the Future • Platforms for Freshman Class Elections • Greaseband Sings its Heart Out to Fortunate Few • Concert Causes Funds Loss • Transplanted Texan: Our Most Illustrious Non-Graduate • Rolling Stones Rock \u27n Roll Circus Levels JFK • Ursinus News Briefs: Postage hike finally granted; \u27Dealing with Stress\u27 offered by evening school • Campus Craziness: Sorority Pledging Begins • Red Cross Bloodmobile at HH • Women Receive Special Attention for Founder\u27s Day • Parents Day: Oct. 10 • Volleyball Holding Even • Soccer Registers First Win • Bears Surrender Lead to Tie Moravian at 10 • Hockey Pulls Out Win in Last Seconds • X-Country Makes it Look Easy . . . Againhttps://digitalcommons.ursinus.edu/grizzlynews/1062/thumbnail.jp
Prevalence of problem alcohol use among patients attending primary care for methadone treatment
<p>Abstract</p> <p>Background</p> <p>Problem alcohol use is associated with adverse health outcomes among current or former heroin users and primary care is providing methadone treatment for increasing numbers of this population. This study aimed todetermine the prevalence of problem alcohol use among current or former heroin users attending primary care for methadone treatment and to describe the socio-demographic characteristics and health service utilisation characteristics associated with problem alcohol uses.</p> <p>Methods</p> <p>We conducted a cross sectional survey of patients sampled from a national database of patients attending general practice for methadone treatment. Participants were recruited by their general practitioner and data was collected using an interviewer-administered questionnaire, which included the Alcohol Use Disorders Identification Test ('AUDIT'), with a score of >7 considered abnormal (ie 'AUDIT positive cases') and socio-demographic, medical and substance use characteristics.</p> <p>Results</p> <p>We interviewed 196 patients (71% of those invited, 31% of those sampled, 11% of the national database). The median age was 32 years, 55% were hepatitis C positive, 79% had used illicit drugs in the previous month and 68% were male. Sixty-eight 'AUDIT positive' cases were identified (prevalence of 35%, 95% CI = 28–41%) and these were more likely to have attended a local Emergency Department in the previous year (p < 0.05) and less likely to have attended a hospital clinic in the previous year (p < 0.05). Twenty-seven (14%) scored 20 or higher indicating possible alcohol dependence.</p> <p>Conclusion</p> <p>Problem alcohol use has a high prevalence among current or former heroin users attending primary care for methadone treatment and interventions that address this issue should be explored as a priority. Interventions that address problem alcohol use in this population should be considered as a priority, although the complex medical and psychological needs of this population may make this challenging.</p
The Future of American Sentencing: A National Roundtable on Blakely
In the wake of the dramatic Supreme Court decision in Blakely v. Washington, Stanford Law School convened an assembly of the most eminent academic and professional sentencing experts in the country to jointly assess the meaning of the decision and its implications for federal and state sentencing reform. The event took place on October 8 and 9, just a few months after Blakely came down and the very week that the Supreme Court heard the arguments in United States v. Booker and United States v. Fanfan, the cases that will test Blakely\u27s application to the Federal Sentencing Guidelines. Thus the Roundtable offered these experts an intellectual breathing space at a crucial point in American criminal law.
The event was built around six sessions, with shifting panels of participants doing brief presentations on the subject of the session, and with others then joining in the discussion. We are pleased that FSR is able to publish this version of the proceedings of the event-a condensed and edited transcript of the sessions
Costs of Testing for Ocular Chlamydia trachomatis Infection Compared to Mass Drug Administration for Trachoma in The Gambia: Application of Results from the PRET Study
Background
Mass drug administration (MDA) treatment of active trachoma with antibiotic is recommended to be initiated in any district where the prevalence of trachoma inflammation, follicular (TF) is ≥10% in children aged 1–9 years, and then to continue for at least three annual rounds before resurvey. In The Gambia the PRET study found that discontinuing MDA based on testing a sample of children for ocular Chlamydia trachomatis(Ct) infection after one MDA round had similar effects to continuing MDA for three rounds. Moreover, one round of MDA reduced disease below the 5% TF threshold. We compared the costs of examining a sample of children for TF, and of testing them for Ct, with those of MDA rounds.
Methods
The implementation unit in PRET The Gambia was a census enumeration area (EA) of 600–800 people. Personnel, fuel, equipment, consumables, data entry and supervision costs were collected for census and treatment of a sample of EAs and for the examination, sampling and testing for Ct infection of 100 individuals within them. Programme costs and resource savings from testing and treatment strategies were inferred for the 102 EAs in the study area, and compared.
Results
Census costs were 108.79. MDA with donated azithromycin cost 796.90 per EA, with Ct testing kits costing 1.38 per result. However stopping or deciding not to initiate treatment in the study area based on testing a sample of EAs for Ct infection (or examining children in a sample of EAs) creates savings relative to further unnecessary treatments.
Conclusion
Resources may be saved by using tests for chlamydial infection or clinical examination to determine that initial or subsequent rounds of MDA for trachoma are unnecessary
Executive functions in preschool children with aggressive behavior: impairments in inhibitory control
The question whether executive function (EF)
deficits in children are associated with conduct problems
remains controversial. Although the origins of aggressive
behavior are to be found in early childhood, findings from
EF studies in preschool children with aggressive behavior
are inconsistent. The current study aimed to investigate
whether preschool children with aggressive behavior show
impairments in EF. From a population-based sample, 82
preschool children who were showing aggressive behavior
as indicated by scores at or above the 93rd percentile on the
Aggressive Behavior Scale of the CBCL 1 1/2-5 were
selected. These children with aggressive behavior were
matched on IQ to a group of typically developing control
children (N=99). Six neuropsychological tasks were administered
to assess set shifting, inhibition, working memory
and verbal fluency. A factor analysis was conducted which
yielded one clear factor: inhibition. Aggressive preschool children showed poorer performance on this inhibition
factor than control children and boys performed worse on
this factor than girls. This association between aggressive
behavior and inhibition deficits was maintained after controlling
for attention problems. In addition, gender differences
in all EFs measured were found with boys exhibiting
more impairment in EF than girls. These findings demonstrate
that preschool children with aggressive behavior show
impairments in inhibition, irrespective of attention problems
Kinematics and physical properties of Southern interacting galaxies: the minor merger AM 2306-721
We present an observational study about the effects of the interactions in
the kinematics, stellar population and abundances of the components of the
galaxy pair AM2306-721. Rotation curves for the main and companion galaxies
were obtained, showing a deprojected velocity amplitude of 175 km/s and 185
km/s, respectively. The interaction between the main and companion galaxies was
modeled using numerical N-body/hydrodynamical simulations, with the result
indicating that the current stage of the merger would be about 250 Myr after
perigalacticum. The spatial variation in the distribution of the stellar
population components in both galaxies was analysed by fitting combinations of
stellar population models of different age groups. The central region of main
galaxy is dominated by an old (5-10 Gyr) population, while significant
contributions from a young (200 Myr) and intermediate (1 Gyr) components are
found in the disk, being enhanced in the direction of the tidal features. The
stellar population of the companion galaxy is overall much younger, being
dominated by components with 1 Gyr or less, quite widely spread over the whole
disk. Spatial profiles of the oxygen abundance were obtained from the a grid of
photoionization models using the R23 line ratio. The disk of the main galaxy
shows a clear radial gradient, while the companion galaxy presents an oxygen
abundance relatively homogeneous across the disk. The absence of an abundance
gradient in the secondary galaxy is interpreted in terms of mixing by gas flows
from the outer parts to the center of the galaxy due to the gravitational
interaction with the more massive primary.Comment: 13 pages, 12 figures, accepted for publication on MNRA
Association of Coding Variants in Hydroxysteroid 17-beta Dehydrogenase 14 (HSD17B14) with Reduced Progression to End Stage Kidney Disease in Type 1 Diabetes
Background Rare variants ingenecodingregions likely have agreater impactondisease-relatedphenotypes than common variants through disruption of their encoded protein. We searched for rare variants associated with onset of ESKD in individuals with type 1 diabetes at advanced kidney disease stage. Methods Gene-basedexome array analyses of15,449genes infivelarge incidence cohortsof individualswith type 1diabetes andproteinuriawere analyzedfor survival time toESKD, testing the top gene in a sixth cohort (n52372/1115 events all cohorts) and replicating in two retrospective case-control studies (n51072 cases, 752 controls). Deep resequencing of the top associated gene in five cohorts confirmed the findings. We performed immunohistochemistry and gene expression experiments in human control and diseased cells, and in mouse ischemia reperfusion and aristolochic acid nephropathy models. Results Protein coding variants in the hydroxysteroid 17- b dehydrogenase 14 gene (HSD17B14), predicted to affect protein structure, had a net protective effect against development of ESKD at exome-wide significance (n54196; P value53.331027). The HSD17B14 gene and encoded enzyme were robustly expressed in healthy human kidney, maximally in proximal tubular cells. Paradoxically, gene and protein expression were attenuated in human diabetic proximal tubules and in mouse kidney injury models. Expressed HSD17B14 gene and protein levels remained low without recovery after 21 days in a murine ischemic reperfusion injury model. Decreased gene expression was found in other CKD-associated renal pathologies. Conclusions HSD17B14 gene ismechanistically involved in diabetic kidney disease. The encoded sex steroid enzyme is a druggable target, potentially opening a new avenue for therapeutic development.Peer reviewe
A missense variant in CST3 exerts a recessive effect on susceptibility to age-related macular degeneration resembling its association with Alzheimer’s disease
Age-related macular degeneration (AMD) and Alzheimer’s disease (AD) are degenerative, multifactorial diseases involving age-related accumulation of extracellular deposits linked to dysregulation of protein homeostasis. Here, we strengthen the evidence that an nsSNP (p.Ala25Thr) in the cysteine proteinase inhibitor cystatin C gene CST3, previously confirmed by meta-analysis to be associated with AD, is associated with exudative AMD. To our knowledge, this is the first report highlighting a genetic variant that increases the risk of developing both AD and AMD. Furthermore, we demonstrate that the risk associated with the mutant allele follows a recessive model for both diseases. We perform an AMD-CST3 case–control study genotyping 350 exudative AMD Caucasian individuals. Bringing together our data with the previously reported AMD-CST3 association study, the evidence of a recessive effect on AMD risk is strengthened (OR = 1.89, P = 0.005). This effect closely resembles the AD-CST3 recessive effect (OR = 1.73, P = 0.005) previously established by meta-analysis. This resemblance is substantiated by the high correlation between CST3 genotype and effect size across the two diseases (R2 = 0.978). A recessive effect is in line with the known function of cystatin C, a potent enzyme inhibitor. Its potency means that, in heterozygous individuals, a single functional allele is sufficient to maintain its inhibitory function; only homozygous individuals will lack this form of proteolytic regulation. Our findings support the hypothesis that recessively acting variants account for some of the missing heritability of multifactorial diseases. Replacement therapy represents a translational opportunity for individuals homozygous for the mutant allele
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