Community-based participatory irrigation management at local government level in Ghana

Ghana has attempted to decentralise the management of irrigation schemes to communities at local government level. This study examines the existing local participatory management structures and the principles of the Participatory Irrigation Management (PIM) strategy designed to promote sustainable management of irrigation schemes in Ghana. Two community-based irrigation projects, Bontanga and Golinga in the Northern Region of Ghana were selected for the research. The study demonstrated that farmers’ participation was minimal and limited to the discussion of irrigation service charges at the expense of other issues related to the sustainability of the projects/schemes. The study also established that there was less participation of women, and more than half of all the crop farmers on the two irrigation projects were reluctant to assume additional responsibilities without remuneration. The study therefore concluded that the sustainability of the PIM strategy depends on the adoption of an integrated management approach involving all stakeholders including local government, with appropriate incentives

Higgs portal dark matter and neutrino mass and mixing with a doubly charged scalar

We consider an extension of the Standard Model involving two new scalar particles around the TeV scale: a singlet neutral scalar $\phi$, to be eventually identified as the Dark Matter candidate, plus a doubly charged $SU(2)_L$ singlet scalar, $S^{++}$, that can be the source for the non-vanishing neutrino masses and mixings. Assuming an unbroken $Z_2$ symmetry in the scalar sector, under which only the additional neutral scalar $\phi$ is odd, we write the most general (renormalizable) scalar potential. The model may be regarded as a possible extension of the conventional Higgs portal Dark Matter scenario which also accounts for neutrino mass and mixing. This framework cannot completely explain the observed positron excess. However a softening of the discrepancy observed in conventional Higgs portal framework can be obtained, especially when the scale of new physics responsible for generating neutrino masses and lepton number violating processes is around 2 TeV.Comment: 16 pages, 4 figure

Stating Appointment Costs in SMS Reminders Reduces Missed Hospital Appointments: Findings from Two Randomised Controlled Trials

BACKGROUND: Missed hospital appointments are a major cause of inefficiency worldwide. Healthcare providers are increasingly using Short Message Service reminders to reduce 'Did Not Attend' (DNA) rates. Systematic reviews show that sending such reminders is effective, but there is no evidence on whether their impact is affected by their content. Accordingly, we undertook two randomised controlled trials that tested the impact of rephrasing appointment reminders on DNA rates in the United Kingdom. TRIAL METHODS: Participants were outpatients with a valid mobile telephone number and an outpatient appointment between November 2013 and January 2014 (Trial One, 10,111 participants) or March and May 2014 (Trial Two, 9,848 participants). Appointments were randomly allocated to one of four reminder messages, which were issued five days in advance. Message assignment was then compared against appointment outcomes (appointment attendance, DNA, cancellation by patient). RESULTS: In Trial One, a message including the cost of a missed appointment to the health system produced a DNA rate of 8.4%, compared to 11.1% for the existing message (OR 0.74, 95% CI 0.61-0.89, P<0.01). Trial Two replicated this effect (DNA rate 8.2%), but also found that expressing the same concept in general terms was significantly less effective (DNA rate 9.9%, OR 1.22, 95% CI 1.00-1.48, P<0.05). Moving from the existing reminder to the more effective costs message would result in 5,800 fewer missed appointments per year in the National Health Service Trust in question, at no additional cost. The study's main limitations are that it took place in a single location in England, and that it required accurate phone records, which were only obtained for 20% of eligible patients. We conclude that missed appointments can be reduced, for no additional cost, by introducing persuasive messages to appointment reminders. Future studies could examine the impact of varying reminder messages in other health systems. TRIAL REGISTRATION: Controlled-Trials.com 49432571

The bottom of the white dwarf cooling sequence in the old open cluster NGC 2158

We use 10 orbits of Advanced Camera for Surveys observations to reach the end of the white dwarf cooling sequence in the solar-metallicity open cluster NGC 2158. Our photometry and completeness tests show that the end falls at magnitude m_F606W = 27.5 +/- 0.15, which implies an age between ~1.8 and ~2.0 Gyr, consistent with the age of 1.9 +/- 0.2 Gyr obtained from fits to the main-sequence turn-off. The faintest white dwarfs show a clear turn toward bluer colors, as predicted by theoretical isochrones.Comment: 12 pages, 4 figures (2 in low resolution, and 1 bonus for astro-ph-only). ApJ Letter accepted on December 1, 200

The Patient Health Questionnaire-9 for detection of major depressive disorder in primary care: consequences of current thresholds in a crosssectional study

Background: There is a need for brief instruments to ascertain the diagnosis of major depressive disorder. In this study, we present the reliability, construct validity and accuracy of the PHQ-9 and PHQ-2 to detect major depressive disorder in primary care.Methods: Cross-sectional analyses within a large prospective cohort study (PREDICT-NL). Data was collected in seven large general practices in the centre of the Netherlands. 1338 subjects were recruited in the general practice waiting room, irrespective of their presenting complaint. The diagnostic accuracy (the area under the ROC curve and sensitivities and specificities for various thresholds) was calculated against a diagnosis of major depressive disorder determined with the Composite International Diagnostic Interview (CIDI).Results: The PHQ-9 showed a high degree of internal consistency (ICC = 0.88) and test-retest reliability (correlation = 0.94). With respect to construct validity, it showed a clear association with functional status measurements, sick days and number of consultations. The discriminative ability was good for the PHQ-9 (area under the ROC curve = 0.87, 95% CI: 0.84-0.90) and the PHQ-2 (ROC area = 0.83, 95% CI 0.80-0.87). Sensitivities at the recommended thresholds were 0.49 for the PHQ-9 at a score of 10 and 0.28 for a categorical algorithm. Adjustment of the threshold and the algorithm improved sensitivities to 0.82 and 0.84 respectively but the specificity decreased from 0.95 to 0.82 (threshold) and from 0.98 to 0.81 (algorithm). Similar results were found for the PHQ-2: the recommended threshold of 3 had a sensitivity of 0.42 and lowering the threshold resulted in an improved sensitivity of 0.81.Conclusion: The PHQ-9 and the PHQ-2 are useful instruments to detect major depressive disorder in primary care, provided a high score is followed by an additional diagnostic work-up. However, often recommended thresholds for the PHQ-9 and the PHQ-2 resulted in many undetected major depressive disorders

Inference of the genetic network regulating lateral root initiation in Arabidopsis thaliana

Regulation of gene expression is crucial for organism growth, and it is one of the challenges in Systems Biology to reconstruct the underlying regulatory biological networks from transcriptomic data. The formation of lateral roots in Arabidopsis thaliana is stimulated by a cascade of regulators of which only the interactions of its initial elements have been identified. Using simulated gene expression data with known network topology, we compare the performance of inference algorithms, based on different approaches, for which ready-to-use software is available. We show that their performance improves with the network size and the inclusion of mutants. We then analyse two sets of genes, whose activity is likely to be relevant to lateral root initiation in Arabidopsis, by integrating sequence analysis with the intersection of the results of the best performing methods on time series and mutants to infer their regulatory network. The methods applied capture known interactions between genes that are candidate regulators at early stages of development. The network inferred from genes significantly expressed during lateral root formation exhibits distinct scale-free, small world and hierarchical properties and the nodes with a high out-degree may warrant further investigation

Seasonal variations in Greenland Ice Sheet motion : Inland extent and behaviour at higher elevations

Peer reviewedPreprin

Realization of Minimal Supergravity

Minimal supergravity mediation of supersymmetry breaking has attracted much attention due to its simplicity, which leads to its predictive power. We consider how Nature possibly realizes minimal supergravity through inflationary selection of the theory. Minimality is impressively consistent with the present observational bounds and it might be tested with the aid of low-energy soft parameters obtained in future experiments.Comment: 18 pages, 5 figure

External Shear in Quadruply Imaged Lens Systems

We use publicly available N-body simulations and semi-analytic models of galaxy formation to estimate the levels of external shear due to structure near the lens in gravitational lens systems. We also describe two selection effects, specific to four-image systems, that enhance the probability of observing systems to have higher external shear. Ignoring additional contributions from "cosmic shear" and assuming that lens galaxies are not significantly flattened, we find that the mean shear at the position of a quadruple lens galaxy is 0.11, the rms shear is roughly 0.15, and there is roughly a 45% likelihood of external shear greater than 0.1. This is much larger than previous estimates and in good agreement with typical measured external shear. The higher shear primarily stems from the tendency of early-type galaxies, which are the majority of lenses, to reside in overdense regions.Comment: 5 pages, 2 figures, ApJ in press, minor revision

Why Low-Mass Black-Hole Binaries Are Transient

We consider transient behavior in low-mass X-ray binaries. In short-period neutron-star systems (orbital period less than ~ 1d) irradiation of the accretion disk by the central source suppresses this except at very low mass transfer rates. Formation constraints however imply that a significant fraction of these neutron star systems have nuclear-evolved main-sequence secondaries and thus mass transfer rates low enough to be transient. But most short-period low-mass black-hole systems will form with unevolved main-sequence companions and have much higher mass transfer rates. The fact that essentially all of them are nevertheless transient shows that irradiation is weaker, as a direct consequence of the fundamental black-hole property - the lack of a hard stellar surface.Comment: 13 pages (including 3 figures); accepted for publication in Ap