260 research outputs found
Perspectives of National Coordinators and Partners on the Work of the Global Trachoma Mapping Project.
PURPOSE: Neglected tropical diseases (NTDs) affect people living in the poorest regions of the world and their debilitating effects perpetuate the poverty cycle. Understanding the distribution of NTDs is crucial for effective intervention delivery. In 2012, the Global Trachoma Mapping Project (GTMP) was initiated to map >1800 suspected trachoma endemic districts by March 2015. This research was carried out to better understand the implementation experience and identify lessons which might inform the GTMP and similar initiatives. METHODS: Using grounded theory methodology, semi-structured interviews were conducted with key informants from six countries with 63% of the global mapping backlog (Ethiopia, Malawi, Mozambique, Nigeria, Solomon Islands, and Yemen). Interviews were transcribed, coded, and findings separated into categories. RESULTS: Three themes were identified during the research; planning and operations, technical implementation, and governance. The project was felt to be most successful in countries where the Ministry of Health was actively engaged in setting standards, ensuring capacity building for government staff, and guiding the training, data collection, analysis, and interpretation of data. Standardized tools, training platforms, and the use of electronic data capture increased confidence in the reliability of the survey data, informed quality improvement efforts within survey implementation, and the immediate release of results empowered end-user decision-makers. Regional collaboration between endemic countries bolstered program manager competence and confidence, while reinforcing partnerships essential to the success of the GTMP. CONCLUSIONS: We depict how innovative characteristics of the GTMP, and lessons learned from its implementation, can strengthen similar initiatives to map disease prevalence and risk factors
Plantevern i veksthus, prydplanter. Integrert bekjempelse
Boka Plantevern i veksthus, prydplanter – integrert bekjempelsehører med i en serie om integrert plantevern i forskjellige kulturer. Bøkene er ment som en del av pensum til autorisasjonskurset i handtering og bruk av plantevernmidler.
Et mål er å hjelpe plantedyrkeren med å utføre en integrert bekjempelse av skadegjørere. Integrert plantevern går ut på å kombinere flere forskjellige bekjempelsestiltak slik at bruken av kjemiske midler blir minst mulig. Samtidig bør resultatet kvalitetsmessig, innenfor en økonomisk forsvarlig ramme, bli best mulig.
I Landbruks- og matdepartementets Handlingsplan for redusert risiko ved bruk av plantevernmidler (1998–2002)heter det: «Planteforsk bør utarbeide veiledende retningslinjer for integrert plantevern, som definerer hvilke krav som bør legges til grunn i de ulike systemene.» Disse retningslinjene er tenkt som et ledd i utviklingen mot en merkeordning for integrerte produkter.
Den som skal kunne utføre integrert bekjempelse, må vite hvordan skadegjørerne ser ut, hvordan deres biologi er, og hvilke tiltak som er aktuelle. Denne boka viser fram sentrale skadegjørere i prydplanter. Ved omtale av kjemiske plantevernmidler har vi valgt ikke å nevne navn på midlene fordi slike opplysninger vil forandre seg over tid. På Mattilsynets internettsider finnes det en oppdatert oversikt over godkjente midler, samt etiketter. Fra februar 2006 vil informasjon om plantevernmiddelbruk i forskjellige kulturer finnes på Planteforsks internettsider
Favoring the Growth of High-Quality, Three-Dimensional Supercrystals of Nanocrystals
A recently developed emulsion-templated assembly method promises the scalable,
low-cost, and reproducible fabrication of hierarchical nanocrystal (NC) superstructures.
These superstructures derive properties from the unique combination of choice of NC
building blocks and superstructure morphology, and therefore realize the concept of
`articial solids'. To control the nal properties of these superstructures, it is essen-
tial to control the assembly conditions yielding distinct architectural morphologies.
Here, we explore the phase-space of experimental parameters describing the emulsion-
templated assembly including: temperature, interfacial tension, and NC polydispersity,
and demonstrate which conditions lead to the growth of the most crystalline NC su-
perstructures, or supercrystals. By using a combination of electron microscopy and
small-angle X-ray scattering, we show that slower assembly kinetics, softer interfaces,
and lower NC polydispersity contribute to the formation of supercrystals with grain
sizes up to 600nm, while reversing these trends yields glassy solids. These results pro-
vide a clear path to the realization of higher-quality supercrystals, necessary to many
applications
Precision mass measurements of magnesium isotopes and implications on the validity of the Isobaric Mass Multiplet Equation
If the mass excess of neutron-deficient nuclei and their neutron-rich mirror
partners are both known, it can be shown that deviations of the Isobaric Mass
Multiplet Equation (IMME) in the form of a cubic term can be probed. Such a
cubic term was probed by using the atomic mass of neutron-rich magnesium
isotopes measured using the TITAN Penning trap and the recently measured
proton-separation energies of Cl and Ar. The atomic mass of
Mg was found to be within 1.6 of the value stated in the Atomic
Mass Evaluation. The atomic masses of Mg were measured to be both
within 1, while being 8 and 34 times more precise, respectively. Using
the Mg mass excess and previous measurements of Cl we uncovered a
cubic coefficient of = 28(7) keV, which is the largest known cubic
coefficient of the IMME. This departure, however, could also be caused by
experimental data with unknown systematic errors. Hence there is a need to
confirm the mass excess of S and the one-neutron separation energy of
Cl, which have both come from a single measurement. Finally, our results
were compared to ab initio calculations from the valence-space in-medium
similarity renormalization group, resulting in a good agreement.Comment: 7 pages, 3 figure
Breakdown of the Isobaric Multiplet Mass Equation for the A = 20 and 21 Multiplets
Using the Penning trap mass spectrometer TITAN, we performed the first direct
mass measurements of 20,21Mg, isotopes that are the most proton-rich members of
the A = 20 and A = 21 isospin multiplets. These measurements were possible
through the use of a unique ion-guide laser ion source, a development that
suppressed isobaric contamination by six orders of magnitude. Compared to the
latest atomic mass evaluation, we find that the mass of 21Mg is in good
agreement but that the mass of 20Mg deviates by 3{\sigma}. These measurements
reduce the uncertainties in the masses of 20,21Mg by 15 and 22 times,
respectively, resulting in a significant departure from the expected behavior
of the isobaric multiplet mass equation in both the A = 20 and A = 21
multiplets. This presents a challenge to shell model calculations using either
the isospin non-conserving USDA/B Hamiltonians or isospin non-conserving
interactions based on chiral two- and three-nucleon forces.Comment: 5 pages, 2 figure
Composition-Tuned Pt-Skinned PtNi Bimetallic Clusters as Highly Efficient Methanol Dehydrogenation Catalysts
Platinum is the most active anode and cathode catalyst in next-generation fuel cells using methanol as liquid source of hydrogen. Its catalytic activity can be significantly improved by alloying with 3d metals, although a precise tuning of its surface architecture is still required. Herein, we report the design of a highly active low-temperature (below 0 °C) methanol dehydrogenation anode catalyst with reduced CO poisoning based on ultralow amount of precisely defined PtxNi1–x (x = 0 to 1) bimetallic clusters (BCs) deposited on inert flat oxides by cluster beam deposition. These BCs feature clear composition-dependent atomic arrangements and electronic structures stemming from their nucleation mechanism, which are responsible for a volcano-type activity trend peaking at the Pt0.7Ni0.3 composition. Our calculations reveal that at this composition, a cluster skin of Pt atoms with d-band centers downshifted by subsurface Ni atoms weakens the CO interaction that in turn triggers a significant increase in the methanol dehydrogenation activity
The surface science of quasicrystals
The surfaces of quasicrystals have been extensively studied since about 1990. In this paper we review work on the structure and morphology of clean surfaces, and their electronic and phonon structure. We also describe progress in adsorption and epitaxy studies. The paper is illustrated throughout with examples from the literature. We offer some reflections on the wider impact of this body of work and anticipate areas for future development.
(Some figures in this article are in colour only in the electronic version
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