Providing marketing information to smallholders in Zimbabwe: What can the state usefully do?

In recent decades, significant international assistance has been provided to assist the establishment of market information systems (MISs) in a range of developing countries, including many in Africa. However, experience with state-run MISs, looking to provide current price information to market participants, has not been encouraging. Volatile horticultural markets provide particular challenges for such MISs. Therefore, it is suggested that it might be more appropriate to provide other types of marketing information to inform the production and marketing decisions of smallholder producers. This paper reports on recent efforts by the national extension agency, Agritex, to provide such information to smallholder horticultural producers in two districts of north-eastern Zimbabwe. Drawing on an initial evaluation of this pilot programme, the paper suggests that: 1) in the Zimbabwe case, the extension service may provide a viable vehicle for dissemination of marketing information to smallholder (horticultural) producers; 2) information on new crops and market opportunities is valued more highly by farmers than information on current market prices; 3) such information should complement, not supplant, traditional production extension advice. The paper concludes by considering some of the issues pertaining to the continuation and expansion of the pilot programme.Marketing,

Virtual patients designed for training against medical error: Exploring the impact of decision-making on learner motivation.

OBJECTIVES: Medical error is a significant cause of patient harms in clinical practice, but education and training are recognised as having a key role in minimising their incidence. The use of virtual patient (VP) activities targeting training in medical error allows learners to practice patient management in a safe environment. The inclusion of branched decision-making elements in the activities has the potential to drive additional generative cognitive processing and improved learning outcomes, but the increased cognitive load on learning risks negatively affecting learner motivation. The aim of this study is to better understand the impact that the inclusion of decision-making and inducing errors within the VP activities has on learner motivation. METHODS: Using a repeated study design, over a period of six weeks we provided undergraduate medical students at six institutions in three countries with a series of six VPs written around errors in paediatric practice. Participants were divided into two groups and received either linearly structured VPs or ones that incorporated branched decision-making elements. Having completed all the VPs, each participant was asked to complete a survey designed to assess their motivation and learning strategies. RESULTS: Our analysis showed that in general, there was no significant difference in learner motivation between those receiving the linear VPs and those who received branched decision-making VPs. The same results were generally reflected across all six institutions. CONCLUSIONS: The findings demonstrated that the inclusion of decision-making elements did not make a significant difference to undergraduate medical students' motivation, perceived self-efficacy or adopted learning strategies. The length of the intervention was sufficient for learners to overcome any increased cognitive load associated with branched decision-making elements being included in VPs. Further work is required to establish any immediate impact within periods shorter than the length of our study or upon achieved learning outcomes

The effect of gender norms on the association between violence and hope among girls in the Democratic Republic of the Congo

Background.Girls at early stages of adolescence are vulnerable to violence victimization in humanitarian contexts, but few studies examine factors that affect girls’ hope in these settings. We assessed attitudes toward traditional gender norms as an effect modifier of the relationship between violence exposure and future orientation in displaced girls.Methods.Secondary analysis, using multivariable regression of cross-sectional data from girls ages 10–14 in South Kivu, Democratic Republic of the Congo. Key variables of interest were attitudes toward intimate partner violence (IPV), Children's Hope Scale (CHS) score, and exposure to physical, emotional, and sexual violence within the last 12 months. Additional covariates included age, educational status, and territory.Results.The interaction of exposure to violence and attitudes toward IPV magnified the association between violence exposure and lower CHS score for physical violence (β = −0.09, p = 0.040) and unwanted sexual touching (β = −0.20, p = 0.003) among girls age 10–14, when adjusting for other covariates. The interaction of exposure to violence and attitudes toward IPV magnified the association between violence exposure and lower CHS score for forced sex (β = −0.22, p = 0.016) among girls age 13–14, when adjusting for covariates. Findings for emotional violence, any form of sexual violence, and coerced sex trended toward lower CHS scores for girls who reported higher acceptance of IPV, but did not reach significance.Conclusions.Findings support the utility of gender norms-transformative programming in increasing resilience of girls who have experienced sexual violence in humanitarian contexts

High-frequency homogenization for periodic media

This article is available open access through the publisher’s website at the link below. Copyright @ 2010 The Royal Society.An asymptotic procedure based upon a two-scale approach is developed for wave propagation in a doubly periodic inhomogeneous medium with a characteristic length scale of microstructure far less than that of the macrostructure. In periodic media, there are frequencies for which standing waves, periodic with the period or double period of the cell, on the microscale emerge. These frequencies do not belong to the low-frequency range of validity covered by the classical homogenization theory, which motivates our use of the term ‘high-frequency homogenization’ when perturbing about these standing waves. The resulting long-wave equations are deduced only explicitly dependent upon the macroscale, with the microscale represented by integral quantities. These equations accurately reproduce the behaviour of the Bloch mode spectrum near the edges of the Brillouin zone, hence yielding an explicit way for homogenizing periodic media in the vicinity of ‘cell resonances’. The similarity of such model equations to high-frequency long wavelength asymptotics, for homogeneous acoustic and elastic waveguides, valid in the vicinities of thickness resonances is emphasized. Several illustrative examples are considered and show the efficacy of the developed techniques.NSERC (Canada) and the EPSRC

Modes of symmetric composite defects in two-dimensional photonic crystals

We consider the modal fields and resonance frequencies of composite defects in two-dimensional photonic crystals (PCs). Using an asymptotic method based on Green's functions, we show that the coupling matrices for the composite defect can be represented as circulant or block-circulant matrices. Using the properties of these matrices, specifically that their eigenvectors are independent of the values of the matrix elements, we obtain modal properties such as dispersion relations, modal cutoff, degeneracy, and symmetry of the mode fields. Using our formulation, we investigate defects arranged on the vertices of regular polygons as well as PC ring resonators with defects arranged on the edges of polygons. Finally, we discuss the impact of band-edge degeneracies on composite-defect modes

The Ediacaran ‘Miaohe Member’ of South China: new insights from palaeoredox proxies and stable isotope data

Throughout the Ediacaran Period, variable water-column redox conditions persisted along productive ocean margins due to a complex interplay between nutrient supply and oceanographic restriction. These changing conditions are considered to have influenced early faunal evolution, with marine anoxia potentially inhibiting the development of the ecological niches necessary for aerobic life forms. To understand this link between oxygenation and evolution, the combined geochemical and palaeontological study of marine sediments is preferable. Located in the Yangtze Gorges region of southern China, lagoonal black shales at Miaohe preserve alga and putative metazoans, including Eoandromeda, a candidate total-group ctenophore, thereby providing one example of where integrated study is possible. We present a multi-proxy investigation into water-column redox variability during deposition of these shales (c. 560–551 Ma). For this interval, reactive iron partitioning indicates persistent water-column anoxia, while trace metal enrichments and other geochemical data suggest temporal fluctuations between ferruginous, euxinic and rare suboxic conditions. Although trace metal and total organic carbon values imply extensive basin restriction, sustained trace metal enrichment and δ15Nsed data indicate periodic access to open-ocean inventories across a shallow-marine sill. Lastly, δ13Corg values of between −35‰ and −40‰ allow at least partial correlation of the shales at Miaohe with Member IV of the Doushantuo Formation. This study provides evidence for fluctuating redox conditions in the lagoonal area of the Yangtze platform during late Ediacaran time. If these low-oxygen environments were regionally characteristic, then the restriction of aerobic fauna to isolated environments can be inferred

BSHI Guideline: HLA matching and donor selection for haematopoietic progenitor cell transplantation

A review of the British Society for Histocompatibility and Immunogenetics (BSHI) "Guideline for selection and HLA matching of related, adult unrelated donors and umbilical cord units for haematopoietic progenitor cell transplantation" was undertaken by a BSHI appointed writing committee. Literature searches were performed, and the data extracted were presented as recommendations according to the GRADE nomenclature

The effect of age and font size on reading text on handheld computers

Though there have been many studies of computer based text reading, only a few have considered the small screens of handheld computers. This paper presents an investigation into the effect of varying font size between 2 and 16 point on reading text on a handheld computer. By using both older and younger participants the possible effects of age were examined. Reading speed and accuracy were measured and subjective views of participants recorded. Objective results showed that there was little difference in reading performance above 6 point, but subjective comments from participants showed a preference for sizes in the middle range. We therefore suggest, for reading tasks, that designers of interfaces for mobile computers provide fonts in the range of 8-12 point to maximize readability for the widest range of users

Modal Analysis Of Enhanced Absorption In Silicon Nanowire Arrays

We analyze the absorption of solar radiation by silicon nanowire arrays, which are being considered for photovoltaic applications. These structures have been shown to have enhanced absorption compared with thin films, however the mechanism responsible for this is not understood. Using a new, semi-analytic model, we show that the enhanced absorption can be attributed to a few modes of the array, which couple well to incident light, overlap well with the nanowires, and exhibit strong Fabry-Perot resonances. For some wavelengths the absorption is further enhanced by slow light effects. We study the evolution of these modes with wavelength to explain the various features of the absorption spectra, focusing first on a dilute array at normal incidence, before generalizing to a dense array and off-normal angles of incidence. The understanding developed will allow for optimization of simple SiNW arrays, as well as the development of more advanced designs