360 research outputs found
What is the impact of contraceptive methods and mixes of contraceptive methods on contraceptive prevalence, unmet need for family planning, and unwanted and unintended pregnancies?
Background - In many low-and middle-income countries, there is high maternal, infant and child mortality due in part to low contraceptive use and high unmet need for family planning. The aim of this overview of systematic reviews is to synthesise the findings of systematic reviews conducted in this area to assess the impact of various contraceptive methods and mixes of contraceptive methods on contraceptive prevalence, unwanted and unintended pregnancies, and unmet need (a desire to limit the number of children but not currently using any contraception) for family planning in developing countries/regions.Methods - Eight databases (Bioline international, The Cochrane Library, Latin American and Caribbean Health Sciences Literature - LILACS, Popline, PubMed, Turning Research Into Practice, World Health Organisation Reproductive Health Library and Zetoc) were searched from 28 October 2010 to 08 December 2010. Cochrane and non-Cochrane systematic reviews were included. Eligible reviews included studies whose participants were sexually active women or men from countries classified as ‘developing’, ‘low-income’ or ‘middle-income’. Systematic reviews of any intervention (or combination of interventions) designed to increase contraceptive prevalence, reduce fertility or both were eligible. Data were extracted and synthesised narratively. A Measurement Tool to Assess Systematic Reviews, AMSTAR, was used to evaluate the quality of the included systematic reviews, and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) was used to evaluate the quality of the body of evidence for each comparison. To aid the interpretation of the findings for a variety of settings, relevant contextual information was presented where possible.Results - There were 22 systematic reviews included in this overview of reviews. The overview examined a range of contraceptive methods, including modern (terminal and spacing) and traditional methods (such as withdrawal and periodic abstinence which do not require contraceptive substances or devices and also do not require clinical procedures). However, the systematic reviews included did not address all the objectives of the overview.The results of the review are summarised below according to the objectives.Objective 1: To assess the impact of various contraceptive methods and mixes ofcontraceptive methods on contraceptive prevalence in developing countries/regions. There was no systematic review that met this objective.Objective 2: To assess the impact of various contraceptive methods and mixes ofcontraceptive methods on unwanted and unintended pregnancies in developingcountries/regions.The body of evidence for the relative efficacy or effectiveness of a variety ofcontraceptive methods to prevent pregnancy in developing countries was generally rated as of low or moderate quality. There was, however, a number of comparisons (between different derivatives of the same contraceptive methods) for which the evidence was rated as of high or moderate quality. Evidence from systematic reviews is lacking on the acceptability of contraceptive methods and their impact on prevalence and on unmet needs for family planning. The evidence for the relative effectiveness of a variety of contraceptive methods to prevent pregnancy in developing countries is generally of low quality. There is some high-quality evidence comparing different derivatives of the same contraceptive methods, although this is more often evidence of efficacy than evidence of effectiveness.Objective 3: To assess the impact of various contraceptive methods and mixes ofcontraceptive methods on unmet need for family planning in developing countries/regions.There was no systematic review that met this objective
Investigations of three, four, and five-particle exit channels of levels in light nuclei created using a 9C beam
The interactions of a E/A=70-MeV 9C beam with a Be target was used to
populate levels in Be, B, and C isotopes which undergo decay into many-particle
exit channels. The decay products were detected in the HiRA array and the level
energies were identified from their invariant mass. Correlations between the
decay products were examined to deduce the nature of the decays, specifically
to what extent all the fragments were created in one prompt step or whether the
disintegration proceeded in a sequential fashion through long-lived
intermediate states. In the latter case, information on the spin of the level
was also obtained. Of particular interest is the 5-body decay of the 8C ground
state which was found to disintegrate in two steps of two-proton decay passing
through the 6Beg.s. intermediate state. The isobaric analog of 8Cg.s. in 8B was
also found to undergo two-proton decay to the isobaric analog of 6Beg.s. in
6Li. A 9.69-MeV state in 10C was found to undergo prompt 4-body decay to the
2p+2alpha exit channel. The two protons were found to have a strong
enhancementin the diproton region and the relative energies of all four p-alpha
pairs were consistent with the 5Lig.s. resonance
Spin alignment of excited projectiles due to target spin-flip interactions
The sequential breakup of E/A=65.5-MeVBe7 and E/A=36.6-MeVLi6 projectiles excited through inelastic interactions with Be9 target nuclei has been studied. For events where the target nucleus remained in its ground state, significant alignment of the excited projectile\u27s spin axis parallel or antiparallel to the beam direction was observed. This unusual spin alignment was found to be largely independent of the projectile\u27s scattering angle and it was deduced that the target nucleus has a significant probability of changing its spin orientation during the interaction. It is proposed that the unusual spin alignment is a consequence of the molecular structure of the Be9 nucleus
Isobaric multiplet mass equation for A=7 and 8
Deviations from the isobaric multiplet mass equation are presented and discussed for the A=7, T=3/2 quartet and the A=8, T=2 quintet. © 2011 American Physical Society
Neutron-proton asymmetry dependence of spectroscopic factors in Ar isotopes
Spectroscopic factors have been extracted for proton rich 34Ar and neutron
rich 46Ar using the (p,d) neutron transfer reaction. The experimental results
show little reduction of the ground state neutron spectroscopic factor of the
proton rich nucleus 34Ar compared to that of 46Ar. The results suggest that
correlations, which generally reduce such spectroscopic factors, do not depend
strongly on the neutron-proton asymmetry of the nucleus in this isotopic region
as was reported in knockout reactions. The present results are consistent with
results from systematic studies of transfer reactions but inconsistent with the
trends observed in knockout reaction measurements.Comment: 11 pages, 2 figures. submitted to PR
Increased activation of blood neutrophils after cigarette smoking in young individuals susceptible to COPD
Background: Cigarette smoking is the most important risk factor for Chronic Obstructive Pulmonary Disease (COPD). Only a subgroup of smokers develops COPD and it is unclear why these individuals are more susceptible to the detrimental effects of cigarette smoking. The risk to develop COPD is known to be higher in individuals with familial aggregation of COPD. This study aimed to investigate if acute systemic and local immune responses to cigarette smoke differentiate between individuals susceptible or non-susceptible to develop COPD, both at young (18-40 years) and old (40-75 years) age. Methods: All participants smoked three cigarettes in one hour. Changes in inflammatory markers in peripheral blood (at 0 and 3 hours) and in bronchial biopsies (at 0 and 24 hours) were investigated. Acute effects of smoking were analyzed within and between susceptible and non-susceptible individuals, and by multiple regression analysis. Results: Young susceptible individuals showed significantly higher increases in the expression of Fc gamma RII (CD32) in its active forms (A17 and A27) on neutrophils after smoking (p = 0.016 and 0.028 respectively), independently of age, smoking status and expression of the respective markers at baseline. Smoking had no significant effect on mediators in blood or inflammatory cell counts in bronchial biopsies. In the old group, acute effects of smoking were comparable between healthy controls and COPD patients. Conclusions: We show for the first time that COPD susceptibility at young age associates with an increased systemic innate immune response to cigarette smoking. This suggests a role of systemic inflammation in the early induction phase of COPD
Low birthweight, preschool education, and school remediation
Abstract
Studies have documented a strong relationship between low birth weight status and adverse child
outcomes such as poor school performance and need for special education services. Following a cohort of
over 1,300 low-income and predominately African American children in the Chicago Longitudinal Study
we investigated whether birth weight and family socio-economic risk measured at the time of the child’s
birth predicts placement into special education classes or grade retention in elementary school. Contrary
to previous research, we found that low birth weight (< 5 ½ pounds) does not predict special education
placement. Rather, these children (especially boys) were more likely to be retained in grade as an
alternative approach to addressing poor school performance. Family socio-economic risk at birth was a
significant predictor of the need for remedial services. We also assessed whether a high-quality preschool
program offered at ages 3 and 4 can reduce the negative effects of low family SES and birth weight on the
need for special education and grade retention. Preschool participation in the Child-Parent Centers was
found to reduce the likelihood of school remediation. The effects of preschool were greater for children
from families with higher levels of socio-economic disadvantage. The beneficial effects of preschool on
special education placement were also larger for boys than girls
Channelized lava flows at the East Pacific Rise crest 9°–10°N : the importance of off-axis lava transport in developing the architecture of young oceanic crust
Author Posting. © American Geophysical Union, 2005. This article is posted here by permission of
American Geophysical Union for personal use, not for redistribution. The definitive version was published
in Geochemistry Geophysics Geosystems 6 (2005): Q08005, doi:10.1029/2005GC000912.Submarine lava flows are the building blocks of young oceanic crust. Lava erupted at the ridge axis is transported across the ridge crest in a manner dictated by the rheology of the lava, the characteristics of the eruption, and the topography it encounters. The resulting lava flows can vary dramatically in form and consequently in their impact on the physical characteristics of the seafloor and the architecture of the upper 50–500 m of the oceanic crust. We have mapped and measured numerous submarine channelized lava flows at the East Pacific Rise (EPR) crest 9°–10°N that reflect the high-effusion-rate and high-flow-velocity end-member of lava eruption and transport at mid-ocean ridges. Channel systems composed of identifiable segments 50–1000 m in length extend up to 3 km from the axial summit trough (AST) and have widths of 10–50 m and depths of 2–3 m. Samples collected within the channels are N-MORB with Mg# indicating eruption from the AST. We produce detailed maps of lava surface morphology across the channel surface from mosaics of digital images that show lineated or flat sheets at the channel center bounded by brecciated lava at the channel margins. Modeled velocity profiles across the channel surface allow us to determine flux through the channels from 0.4 to 4.7 × 103 m3/s, and modeled shear rates help explain the surface morphology variation. We suggest that channelized lava flows are a primary mechanism by which lava accumulates in the off-axis region (1–3 km) and produces the layer 2A thickening that is observed at fast and superfast spreading ridges. In addition, the rapid, high-volume-flux eruptions necessary to produce channelized flows may act as an indicator of the local magma budget along the EPR. We find that high concentrations of channelized lava flows correlate with local, across-axis ridge morphology indicative of an elevated magma budget. Additionally, in locations where channelized flows are located dominantly to the east or west of the AST, the ridge crest is asymmetric, and layer 2A appears to thicken over a greater distance from the AST toward the side of the ridge crest where the channels are located.This work was supported by NSF grant OCE-9819261 (to H.S., M.A.T., and D.J.F.) as well as the Postdoctoral Scholar Program at the Woods Hole Oceanographic Institution, with funding provided by the Penzance Endowed Discretionary Fund
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