64 research outputs found
First spectroscopic measurements of [OIII] emission from Lyman-alpha selected field galaxies at z ~ 3.1
We present the first spectroscopic measurements of the [OIII] 5007 A line in
two z ~ 3.1 Lyman-alpha emitting galaxies (LAEs) using the new near-infrared
instrument LUCIFER1 on the 8.4m Large Binocular Telescope (LBT). We also
describe the optical imaging and spectroscopic observations used to identify
these Lya emitting galaxies. Using the [OIII] line we have measured accurate
systemic redshifts for these two galaxies, and discovered a velocity offset
between the [OIII] and Ly-alpha lines in both, with the Lya line peaking 342
and 125 km/s redward of the systemic velocity. These velocity offsets imply
that there are powerful outflows in high-redshift LAEs. They also ease the
transmission of Lya photons through the interstellar medium and intergalactic
medium around the galaxies. By measuring these offsets directly, we can refine
both Lya-based tests for reionization, and Lya luminosity function measurements
where the Lya forest affects the blue wing of the line. Our work also provides
the first direct constraints on the strength of the [OIII] line in
high-redshift LAEs. We find [OIII] fluxes of 7 and 36 x 10^-17 erg s^-1 cm^-2
in two z ~ 3.1 LAEs. These lines are strong enough to dominate broad-band flux
measurements that include the line (in thiscase, K_s band photometry). Spectral
energy distribution fits that do not account for the lines would therefore
overestimate the 4000 A (and/or Balmer) break strength in such galaxies, and
hence also the ages and stellar masses of such high-z galaxies.Comment: Accepted by the Astrophysical Journal. 11 pages, 3 figures, 1 table
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Impact of Tobacco Control Interventions on Smoking Initiation, Cessation, and Prevalence: A Systematic Review
Background. Policymakers need estimates of the impact of tobacco control (TC) policies to set priorities and targets for reducing tobacco use. We systematically reviewed the independent effects of TC policies on smoking behavior. Methods. We searched MEDLINE (through January 2012) and EMBASE and other databases through February 2009, looking for studies published after 1989 in any language that assessed the effects of each TC intervention on smoking prevalence, initiation, cessation, or price participation elasticity. Paired reviewers extracted data from studies that isolated the impact of a single TC intervention. Findings. We included 84 studies. The strength of evidence quantifying the independent effect on smoking prevalence was high for increasing tobacco prices and moderate for smoking bans in public places and antitobacco mass media campaigns. Limited direct evidence was available to quantify the effects of health warning labels and bans on advertising and sponsorship. Studies were too heterogeneous to pool effect estimates. Interpretations. We found evidence of an independent effect for several TC policies on smoking prevalence. However, we could not derive precise estimates of the effects across different settings because of variability in the characteristics of the intervention, level of policy enforcement, and underlying tobacco control environment
Cell-type-specific long-range looping interactions identify distant regulatory elements of the CFTR gene
Identification of regulatory elements and their target genes is complicated by the fact that regulatory elements can act over large genomic distances. Identification of long-range acting elements is particularly important in the case of disease genes as mutations in these elements can result in human disease. It is becoming increasingly clear that long-range control of gene expression is facilitated by chromatin looping interactions. These interactions can be detected by chromosome conformation capture (3C). Here, we employed 3C as a discovery tool for identification of long-range regulatory elements that control the cystic fibrosis transmembrane conductance regulator gene, CFTR. We identified four elements in a 460-kb region around the locus that loop specifically to the CFTR promoter exclusively in CFTR expressing cells. The elements are located 20 and 80 kb upstream; and 109 and 203 kb downstream of the CFTR promoter. These elements contain DNase I hypersensitive sites and histone modification patterns characteristic of enhancers. The elements also interact with each other and the latter two activate the CFTR promoter synergistically in reporter assays. Our results reveal novel long-range acting elements that control expression of CFTR and suggest that 3C-based approaches can be used for discovery of novel regulatory elements
Small individual loans and mental health: a randomized controlled trial among South African adults
<p>Abstract</p> <p>Background</p> <p>In the developing world, access to small, individual loans has been variously hailed as a poverty-alleviation tool – in the context of "microcredit" – but has also been criticized as "usury" and harmful to vulnerable borrowers. Prior studies have assessed effects of access to credit on traditional economic outcomes for poor borrowers, but effects on mental health have been largely ignored.</p> <p>Methods</p> <p>Applicants who had previously been rejected (n = 257) for a loan (200% annual percentage rate – APR) from a lender in South Africa were randomly assigned to a "second-look" that encouraged loan officers to approve their applications. This randomized encouragement resulted in 53% of applicants receiving a loan they otherwise would not have received. All subjects were assessed 6–12 months later with questions about demographics, socio-economic status, and two indicators of mental health: the Center for Epidemiologic Studies – Depression Scale (CES-D) and Cohen's Perceived Stress scale. Intent-to-treat analyses were calculated using multinomial probit regressions.</p> <p>Results</p> <p>Randomization into receiving a "second look" for access to credit increased perceived stress in the combined sample of women and men; the findings were stronger among men. Credit access was associated with reduced depressive symptoms in men, but not women.</p> <p>Conclusion</p> <p>Our findings suggest that a mechanism used to reduce the economic stress of extremely poor individuals can have mixed effects on their experiences of psychological stress and depressive symptomatology. Our data support the notion that mental health should be included as a measure of success (or failure) when examining potential tools for poverty alleviation. Further longitudinal research is needed in South Africa and other settings to understand how borrowing at high interest rates affects gender roles and daily life activities. CCT: ISRCTN 10734925</p
Human Capital Development and Parental Investment in India
In this paper we estimate production functions for cognition and health throughout four stages of childhood from 5-15 years of age using two cohorts of children drawn from the Young Lives Survey for India. The inputs into the production function include parental background, prior child cognition and health and child investments. We allow investments to be endogenous and they depend on local prices and household income, as well as on the exogenous determinants of cognition and health. We find that investments are very important determinants of child cognition and of health at an earlier age. We also find that inputs are complementary and crucially that health is very important in determining cognition. Our paper contributes in understanding how early health outcomes are important in child development
Can Urinalysis and Past Medical History of Kidney Stones Predict Urine Antibiotic Resistance?
Introduction: Urinary tract infections (UTI) are one of the most common infections encountered in the emergency department (ED) with an estimated 2-3 million annual visits. Commonly prescribed antibiotics for UTIs have shown growing rates of resistance. Previous studies lack direction on improving UTI treatment based on the labs available to the bedside clinician.
Methods: We sought to determine if antibiotic resistance in UTIs was related to demographics, urinalysis, and history of renal failure or kidney stones. We conducted an analysis of 892 women ≥18 years of age discharged from the ED with a UTI diagnosis. We assessed predictors of nitrofurantoin resistance, cefazolin resistance, ciprofloxacin resistance, and trimethoprim-sulfamethoxazole resistance using unadjusted and multivariable logistic regression models.
Results: Antibiotic resistance was 13.6% for nitrofurantoin, 11.9% for cefazolin, 12.8% for ciprofloxacin, and 17.1% for trimethoprim-sulfamethoxazole. In multivariable analysis, significant independent associations with an increased likelihood of resistance to nitrofurantoin were observed for less urine blood (OR [per 1 category increase of score] 0.81; P = 0.02); greater mucous (OR [per 1 category increase of score] 1.22; P = 0.02); less specific gravity urine (OR [per 1 category increase] 0.87; P = 0.04), and presence of any history of kidney stones (OR 3.24; P = 0.01). There were no significant predictors for cefazolin resistance (all P ≥0.06); age was the only significant predictor of ciprofloxacin resistance (OR per 10 year increase] 1.10, P = 0.05), and lower specific gravity urine was significantly associated with an increased risk of resistance to trimethoprim- sulfamethoxazole (OR [per 1 category increase] 0.88, P = 0.04).
Conclusion: Women with any history of kidney stones may have bacteriuria resistant to nitrofurantoin, suggesting that providers might consider alternative antibiotic therapies in this scenario
Optical properties of DNA-CTMA biopolymers and applications in metal-biopolymer-metal photodetectors
The potential of using a DNA biopolymer in an electro-optic device is presented. A complex of DNA with the
cationic surfactant cetyltrimethylammonium-chloride (CTMA) was used to obtain an organic-soluble DNA material
(DNA-CTMA). Poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) was added to the DNACTMA
to increase the electrical conductivity of the biopolymer. The CW absorbance and time-resolved
photoluminescence of the resulting DNA-CTMA and DNA-CTMA-PEDOT:PSS were investigated. Both DNA
materials have absorbance peaks at ~260 nm and a broad, Stokes shifted, photoluminescence peak around 470nm.
The photoluminescence lifetime of the materials was observed to decrease with increasing UV excitation.
Specifically, excitation with a high power ultrafast (~150fs) UV (266nm) laser pulse resulted in a drastic decrease
in the photoluminescence lifetime decreases after a few minutes. Moreover, the observed decrease was faster in an
air ambient than in a nitrogen ambient. This is most likely due to photo-oxidation that degrades the polymer surface
resulting in an increase in the non-radiative recombination. In order to investigate the photoconductivity of these
two materials, metal-biopolymer-metal (MBM) ultraviolet photodetectors with interdigitated electrodes were
fabricated and characterized. The photoresponsivity of these devices was limited by the transport dynamics within
the film. The prospects for the use of these materials in optical devices will be discussed
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Optical properties of DNA-CTMA biopolymers and applications in metal-biopolymer-metal photodetectors
The potential of using a DNA biopolymer in an electro-optic device is presented. A complex of DNA with the
cationic surfactant cetyltrimethylammonium-chloride (CTMA) was used to obtain an organic-soluble DNA material
(DNA-CTMA). Poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) was added to the DNACTMA
to increase the electrical conductivity of the biopolymer. The CW absorbance and time-resolved
photoluminescence of the resulting DNA-CTMA and DNA-CTMA-PEDOT:PSS were investigated. Both DNA
materials have absorbance peaks at ~260 nm and a broad, Stokes shifted, photoluminescence peak around 470nm.
The photoluminescence lifetime of the materials was observed to decrease with increasing UV excitation.
Specifically, excitation with a high power ultrafast (~150fs) UV (266nm) laser pulse resulted in a drastic decrease
in the photoluminescence lifetime decreases after a few minutes. Moreover, the observed decrease was faster in an
air ambient than in a nitrogen ambient. This is most likely due to photo-oxidation that degrades the polymer surface
resulting in an increase in the non-radiative recombination. In order to investigate the photoconductivity of these
two materials, metal-biopolymer-metal (MBM) ultraviolet photodetectors with interdigitated electrodes were
fabricated and characterized. The photoresponsivity of these devices was limited by the transport dynamics within
the film. The prospects for the use of these materials in optical devices will be discussed
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