219 research outputs found
Is Information Power? Using Mobile Phones and Free Newspapers during an Election in Mozambique*
African elections often reveal low levels of political accountability. We assess different forms of voter education during an election in Mozambique. Three interventions providing information to voters and calling for their electoral participation were randomized; an SMS-based information campaign, an SMS hotline for electoral misconduct, and the distribution of a free newspaper. To measure impact, we look at official electoral results, reports by electoral observers, behavioral and survey data. We find positive effects of all treatments on voter turnout. We observe that the distribution of the newspaper led to more accountability-based participation and to a decrease in electoral problems.International Growth Centre, Foundation Open Society Institut
Seafloor sediment thickness beneath the VoiLA broad-band ocean-bottom seismometer deployment in the Lesser Antilles from P-to-S delay times
Broad-band ocean-bottom seismometer (OBS) deployments present an opportunity to investigate the seafloor sediment thickness, which is important for constraining sediment deposition, and is also useful for subsequent seismological analyses. The Volatile Recycling in the Lesser Antilles (VoiLA) project deployed 34 OBSs over the island arc, fore- and backarc of the Lesser Antilles subduction zone for 15 months from 2016 to 2017. Using the amplitudes and delay times of P-to-S (Ps) scattered waves from the conversion of teleseismic earthquake Pwaves at the crust–sediment boundary and pre-existing relationships developed for Cascadia, we estimate sediment thickness beneath each OBS. The delay times of the Ps phases vary from 0.20 ± 0.06 to 3.55 ± 0.70 s, generally increasing from north to south. Using a single-sediment and single-crystalline crust earth model in each case, we satisfactorily model the observations of eight OBSs. At these stations we find sediment thicknesses range from 0.43 ± 0.45 to 5.49 ± 3.23 km. To match the observations of nine other OBSs, layered sediment and variable thickness crust is required in the earth model to account for wave interference effects on the observed arrivals. We perform an inversion with a two-layer sediment and a single-layer crystalline crust in these locations finding overall sediment thicknesses of 1.75 km (confidence region: 1.45–2.02 km) to 7.93 km (confidence region: 6.32–11.05 km), generally thinner than the initial estimates based on the pre-existing relationships. We find agreement between our modelled velocity structure and the velocity structure determined from the VoiLA active-source seismic refraction experiment at the three common locations. Using the Ps values and estimates from the VoiLA refraction experiment, we provide an adjusted relationship between delay time and sediment equations for the Lesser Antilles. Our new relationship is H=1.42dt , where H is sediment thickness in kilometres and dt is mean observed Ps delay time in seconds, which may be of use in other subduction zone settings with thick seafloor sediments
Seafloor sediment thickness beneath the VoiLA broad-band ocean-bottom seismometer deployment in the Lesser Antilles from P-to-S delay times
Broad-band ocean-bottom seismometer (OBS) deployments present an opportunity to investigate the seafloor sediment thickness, which is important for constraining sediment deposition, and is also useful for subsequent seismological analyses. The Volatile Recycling in the Lesser Antilles (VoiLA) project deployed 34 OBSs over the island arc, fore- and backarc of the Lesser Antilles subduction zone for 15 months from 2016 to 2017. Using the amplitudes and delay times of P-to-S (Ps) scattered waves from the conversion of teleseismic earthquake Pwaves at the crust–sediment boundary and pre-existing relationships developed for Cascadia, we estimate sediment thickness beneath each OBS. The delay times of the Ps phases vary from 0.20 ± 0.06 to 3.55 ± 0.70 s, generally increasing from north to south. Using a single-sediment and single-crystalline crust earth model in each case, we satisfactorily model the observations of eight OBSs. At these stations we find sediment thicknesses range from 0.43 ± 0.45 to 5.49 ± 3.23 km. To match the observations of nine other OBSs, layered sediment and variable thickness crust is required in the earth model to account for wave interference effects on the observed arrivals. We perform an inversion with a two-layer sediment and a single-layer crystalline crust in these locations finding overall sediment thicknesses of 1.75 km (confidence region: 1.45–2.02 km) to 7.93 km (confidence region: 6.32–11.05 km), generally thinner than the initial estimates based on the pre-existing relationships. We find agreement between our modelled velocity structure and the velocity structure determined from the VoiLA active-source seismic refraction experiment at the three common locations. Using the Ps values and estimates from the VoiLA refraction experiment, we provide an adjusted relationship between delay time and sediment equations for the Lesser Antilles. Our new relationship is H=1.42dt , where H is sediment thickness in kilometres and dt is mean observed Ps delay time in seconds, which may be of use in other subduction zone settings with thick seafloor sediments
Shaping dental contract reform – a clinical and cost effectiveness analysis of incentive-driven commissioning for improved oral health in primary dental care
Objective: To evaluate the clinical and cost-effectiveness of a new blended dental contract incentivising improved oral health compared with a traditional dental contract based on units of dental activity (UDAs). Design: Non-randomised controlled study. Setting: Six UK primary care dental practices, three working under a new blended dental contract; three matched practices under a traditional contract. Participants: 550 new adult patients. Interventions: A new blended/incentive-driven primary care dentistry contract and service delivery model versus the traditional contract based on UDAs. Main Outcomes Measures: Primary outcome was as follows: percentage of sites with gingival bleeding on probing. Secondary outcomes were as follows: extracted and filled teeth (%), caries (International Caries Detection and Assessment System (ICDAS)), oral health-related quality of life (Oral Health Impact Profile-14 (OHIP-14)). Incremental cost-effective ratios used OHIP-14 and quality adjusted life years (QALYs) derived from the EQ-5D-3L. Results: At 24 months, 291/550 (53%) patients returned for final assessment; those lost to follow-up attended 6.46 appointments on average (SD 4.80). The primary outcome favoured patients in the blended contract group. Extractions and fillings were more frequent in this group. Blended contracts were financially attractive for the dental provider but carried a higher cost for the service commissioner. Differences in generic health-related quality of life were negligible. Positive changes over time in oral health-related quality of life in both groups were statistically significant. Conclusions: This is the first UK study to assess the clinical and cost-effectiveness of a blended contract in primary care dentistry. Although the primary outcome favoured the blended contract, the results are limited because 47% patients did not attend at 24?months. This is consistent with 39% of adults not being regular attenders and 27% only visiting their dentist when they have a problem. Promotion of appropriate attendance, especially among those with high need, necessitates being factored into recruitment strategies of future studies
Invited Article: First flight in space of a wide-field-of-view soft x-ray imager using lobster-eye optics: Instrument description and initial flight results
We describe the development, launch into space, and initial results from a prototype wide field-of-view soft X-ray imager that employs lobster-eye optics and targets heliophysics, planetary, and astrophysics science. The sheath transport observer for the redistribution of mass is the first instrument using this type of optics launched into space and provides proof-of-concept for future flight instruments capable of imaging structures such as the terrestrial cusp, the entire dayside magnetosheath from outside the magnetosphere, comets, the Moon, and the solar wind interaction with planetary bodies like Venus and Mars [Kuntz et al., Astrophys. J. (in press)]
The INCENTIVE Study: a mixed methods evaluation of an innovation in commissioning and delivery of primary dental care compared to traditional dental contracting
Background
Over the past decade, commissioning of primary care dentistry has seen contract currency evolving from payment for units of dental activity (UDAs) towards blended contracts that include key performance indicators such as access, quality and improved health outcome.
Objectives
The aim of this study was to evaluate a blended/incentive-driven model of dental service provision. To (1) explore stakeholder perspectives of the new service delivery model; (2) assess the effectiveness of the new service delivery model in reducing the risk of and amount of dental disease and enhancing oral health-related quality of life (OHQoL) in patients; and (3) assess cost-effectiveness of the new service delivery model.
Methods
Using a mixed-methods approach, the study included three dental practices working under the blended/incentive-driven (incentive) contract and three working under the UDAs (traditional) contract. All were based in West Yorkshire. The qualitative study reports on the meaning of key aspects of the model for three stakeholder groups [lay people (patients and individuals without a dentist), commissioners and the primary care dental teams], with framework analysis of focus group and semistructured interview data. A non-randomised study compared clinical effectiveness and cost-effectiveness of treatment under the two contracts. The primary outcome was gingivitis, measured using bleeding on probing. Secondary outcomes included OHQoL and cost-effectiveness.
Results
Participants in the qualitative study associated the incentive contract with more access, greater use of skill mix and improved health outcomes. In the quantitative analyses, of 550 participants recruited, 291 attended baseline and follow-up. Given missing data and following quality assurance, 188 were included in the bleeding on probing analysis, 187 in the caries assessment and 210 in the economic analysis. The results were mixed. The primary outcome favoured the incentive practices, whereas the assessment of caries favoured the traditional practices. Incentive practices attracted a higher cost for the service commissioner, but were financially attractive for the dental provider at the practice level. Differences in generic health-related quality of life were negligible. Positive changes over time in OHQoL in both groups were statistically significant.
Limitations
The results of the quantitative analysis should be treated with caution given small sample numbers, reservations about the validity of pooling, differential dropout results and data quality issues.
Conclusions
A large proportion of people in this study who had access to a dentist did not follow up on oral care. These individuals are more likely to be younger males and have poorer oral health. Although access to dental services was increased, this did not appear to facilitate continued use of services.
Future work
Further research is required to understand how best to promote and encourage appropriate dental service attendance, especially among those with a high level of need, to avoid increasing health inequalities, and to assess the financial impact of the contract. For dental practitioners, there are challenges around perceptions about preventative dentistry and use of the risk assessments and care pathways. Changes in skill mix pose further challenges.
Funding
The National Institute for Health Research Health Services and Delivery Research programme
Examining the Links between Multi-Frequency Multibeam Backscatter Data and Sediment Grain Size
Publication history: Accepted - 13 April 2021Acoustic methods are routinely used to provide broad scale information on the geographical distribution of benthic marine habitats and sedimentary environments. Although single-frequency multibeam echosounder surveys have dominated seabed characterisation for decades, multifrequency approaches are now gaining favour in order to capture different frequency responses from the same seabed type. The aim of this study is to develop a robust modelling framework for testing the potential application and value of multifrequency (30, 95, and 300 kHz) multibeam backscatter responses to characterize sediments’ grain size in an area with strong geomorphological gradients and benthic ecological variability. We fit a generalized linear model on a multibeam backscatter and its derivatives to examine the explanatory power of single-frequency and multifrequency models with respect to the mean sediment grain size obtained from the grab samples. A strong and statistically significant (p < 0.05) correlation between the mean backscatter and the absolute values of the mean sediment grain size for the data was noted. The root mean squared error (RMSE) values identified the 30 kHz model as the best performing model responsible for explaining the most variation (84.3%) of the mean grain size at a statistically significant output (p < 0.05) with an adjusted r2 = 0.82. Overall, the single low-frequency sources showed a marginal gain on the multifrequency model, with the 30 kHz model driving the significance of this multifrequency model, and the inclusion of the higher frequencies diminished the level of agreement. We recommend further detailed and sufficient ground-truth data to better predict sediment properties and to discriminate benthic habitats to enhance the reliability of multifrequency backscatter data for the monitoring and management of marine protected areas.This research was funded by the Marine Institute under the Marine Research Programme by
the Irish Government Cruise CE19007 Backscatter and Biodiversity of Shelf Sea Habitats (BaBioSSH)
survey. Staffing was supported through the Marine Protected Area Monitoring and Management
(MarPAMM) project, which is supported by the European Union’s INTERREG VA Programme, managed by the Special EU Programmes Body (SEUPM) with matching funding from the Government of
Ireland, the Northern Ireland Executive, and the Scottish Government, as well as the PhD studentship
through a Vice Chancellor Research Scholarship of Ulster University (U.K.)
Imaging slab-transported fluids and their deep dehydration from seismic velocity tomography in the Lesser Antilles subduction zone
Volatiles play a pivotal role in subduction zone evolution, yet their pathways remain poorly constrained. Studying the Lesser Antilles subduction zone can yield new constraints, where old oceanic lithosphere formed by slow-spreading subducts slowly. Here we use local earthquakes recorded by the temporary VoiLA (Volatile recycling in the Lesser Antilles) deployment of ocean-bottom seismometers in the fore- and back-arc to characterize the 3-D seismic structure of the north-central Lesser Antilles subduction zone. Along the slab top, mapped based on seismicity, we find low Vp extending to 130–150 km depth, deeper than expected for magmatic oceanic crust. The slab's most prominent, elevated Vp/Vs anomalies are beneath the fore- and back-arc offshore Guadeloupe and Dominica, where two subducted fracture zones lie with the obliquely subducting boundary between Proto-Caribbean and Equatorial Atlantic lithosphere. These structures, therefore, enhance hydration of the oceanic lithosphere as it forms and evolves and the subsequent dehydration of mantle serpentinite when subducted. Above the slab, we image the asthenosphere wedge as a high Vp/Vs and moderate Vp feature, indicating slab-dehydrated fluids rising through the overlying cold boundary layer that might induce melting further to the west. Our results provide new evidence for the impact of spatially-variable oceanic plate formation processes on slab dehydration and mantle wedge volatile transfer that ultimately impact volcanic processes at the surface, such as the relatively high magmatic output observed on the north-central islands in the Lesser Antilles
The Lick AGN Monitoring Project: Photometric Light Curves and Optical Variability Characteristics
The Lick AGN Monitoring Project targeted 13 nearby Seyfert 1 galaxies with
the intent of measuring the masses of their central black holes using
reverberation mapping. The sample includes 12 galaxies selected to have black
holes with masses roughly in the range 10^6-10^7 solar masses, as well as the
well-studied AGN NGC 5548. In conjunction with a spectroscopic monitoring
campaign, we obtained broad-band B and V images on most nights from 2008
February through 2008 May. The imaging observations were carried out by four
telescopes: the 0.76-m Katzman Automatic Imaging Telescope (KAIT), the 2-m
Multicolor Active Galactic Nuclei Monitoring (MAGNUM) telescope, the Palomar
60-in (1.5-m) telescope, and the 0.80-m Tenagra II telescope. Having
well-sampled light curves over the course of a few months is useful for
obtaining the broad-line reverberation lag and black hole mass, and also allows
us to examine the characteristics of the continuum variability. In this paper,
we discuss the observational methods and the photometric measurements, and
present the AGN continuum light curves. We measure various variability
characteristics of each of the light curves. We do not detect any evidence for
a time lag between the B- and V-band variations, and we do not find significant
color variations for the AGNs in our sample.Comment: 16 pages, 20 figures, 8 tables, accepted for publication in ApJ
Long Term Follow-Up of Patients with Chronic Hepatitis C Treated with Alpha Interferon
Interferon
alpha (IFN) treatment for chronic hepatitis C induces a
sustained biochemical and virological response at six months after
completing 24 weeks of therapy in approximately 10% of patients.
The long term durability of this ‘sustained’ response is still controversial.
The aim of this multicentre study was to assess the long
term virological response in patients considered to have achieved
a sustained biochemical response six months after completing IFN
treatment. The majority (36 of 41) of the sustained responders
identified had been treated for six months with IFN therapy.
Twenty-nine of the 41 patients (70%) had undetectable hepatitis
C virus (HCV) RNA after a mean follow-up of 38 months after
cessation of treatment (range six to 92 months). All but one of
those 29 individuals had normal serum alanine aminotransferase
(ALT) levels. Of the 16 patients (out of 41) who had been tested
for HCV RNA six months after treatment, HCV RNA remained
undetectable in 14 (88%) at final follow-up. Serum ALT values in
the 11 of 12 patients whose HCV RNA was positive at final
follow-up were lower than pretreatment values, and in six cases
were within the normal range. The long term sustained virological
response in those considered a ‘sustained responder’ six months after
receiving only six months of IFN is high. Measurement of ALT
is an unreliable marker of sustained response to therapy
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