1,645 research outputs found

    Exploring the effectiveness of a rapid participatory method in mapping the role of agricultural biodiversity in local food systems to identify potential entry points to improve peoples' capabilities to be nutrition secure

    Get PDF
    Vietnam has improved its food security situation at the price of losing traditional varieties adapted to local tastes and conditions due to increased production and use of high-yield crop varieties (mainly large scale mono-cropping). Decreased diversity of foods is a growing issue, and the existence of malnutrition in regions where staple crop production and food availability are sufficient highlights the necessity for a multidisciplinary approach to design interventions that target the four dimensions of food security - availability, access, stability and utilisation, of a diverse group of locally available nutritious foods. This paper demonstrates the use of the Four Cell Approach to participatory research to rapidly identify trends in a) species and food usage in a landscape and b) the dynamics of the food system which may contribute to, or be leveraged to improve, peoples' capabilities to be nutrition secure. In the case of Son La Province, Vietnam, explored in this paper, it is possible to conclude a positive relationship between increased production diversity and dietary diversity, and highlight the importance of markets for diffusion of diverse foods. Diversification of species production and consumption has a positive effect on resilience during the off-season, and diversification of coping mechanisms utilised by communities can build resilience for future shocks. Food-based approaches that promote diversified production and consumption of locally available nutritious foods that local people value, while ensuring access to markets, have the potential to improve capabilities of local people to provide nutritious foods for themselves and their communities while improving resilience to be food and nutrition secure at all time

    Offering within-category food swaps to reduce energy density of food purchases: a study using an experimental online supermarket.

    Get PDF
    BACKGROUND: Swaps are often used to encourage healthier food choices, but there is little evidence of their effectiveness. The current study assessed the impact of offering swaps on groceries purchased within a bespoke online supermarket; specifically the objective was to measure the impact on energy density (ED) of food purchases following the offer of lower ED alternatives (a) at point of selection or at checkout, and (b) with or without explicit consent to receive swap prompts. METHOD: Participants were asked to complete a 12-item shopping task within an online shopping platform, developed for studying food purchasing. 1610 adults were randomly assigned to a no swap control condition or to one of four interventions: consented swaps at selection; consented swaps at checkout; imposed swaps at selection; or imposed swaps at checkout. Each swap presented two lower ED options from the same category as the participant's chosen food. Swap acceptance rate and purchased food ED were the primary outcomes. RESULTS: Of the mean 12.36 (SD 1.26) foods purchased, intervention participants were offered a mean of 4.1 (SD 1.68) swaps, with the potential to reduce the ED of purchased food (effect (95% CI): -83 kJ/100 g (-110 - -56), p = <0.0001). A median of one swap (IQR 0 to 2) was accepted, not significantly reducing the purchased food ED (effect (95% CI): -24 kJ/100 g (4 - -52), p = 0.094). More swaps were accepted when offered at selection than at checkout (OR (95% CI) = 1.224 (1.11 - 1.35), p < 0.0001), but no differences were seen with consent. Purchased food ED was unaffected by point of swap or consent, but reduced with number of swaps accepted (effect per swap (95% CI) = -24 kJ/100 g (-35 - -14), p < 0.0001). CONCLUSION: Within category swaps did not reduce the ED of food purchases reflecting the observation that the use of swaps within an on-line shopping platform offered small potential gains in ED and a minority was accepted.This work was funded by the Department of Health (England) Policy Research Program (Policy Research Unit in Behaviour and Health [PR-UN-0409-10109]).This is the final version. It was first published by BioMed Central at http://dx.doi.org/10.1186/s12966-015-0241-

    Evaluating LANDSAT-4 MSS and TM data

    Get PDF
    Interband line pixel misregistrations were determined for the four MSS bands of the Mistassini, Ontario scene and multitemporal registration of LANDSAT-4 products were tested for two different geocoded scenes. Line and pixel misregistrations are tabulated as determined by the manual ground control points and the digital band to band correlation techniques. A method was developed for determining the spectral information content of TM images for forestry applications

    Production of Secondary Organic Aerosol During Aging of Biomass Burning Smoke From Fresh Fuels and Its Relationship to VOC Precursors

    Get PDF
    After smoke from burning biomass is emitted into the atmosphere, chemical and physical processes change the composition and amount of organic aerosol present in the aged, diluted plume. During the fourth Fire Lab at Missoula Experiment, we performed smog-chamber experiments to investigate formation of secondary organic aerosol (SOA) and multiphase oxidation of primary organic aerosol (POA). We simulated atmospheric aging of diluted smoke from a variety of biomass fuels while measuring particle composition using high-resolution aerosol mass spectrometry. We quantified SOA formation using a tracer ion for low-volatility POA as a reference standard (akin to a naturally occurring internal standard). These smoke aging experiments revealed variable organic aerosol (OA) enhancements, even for smoke from similar fuels and aging mechanisms. This variable OA enhancement correlated well with measured differences in the amounts of emitted volatile organic compounds (VOCs) that could subsequently be oxidized to form SOA. For some aging experiments, we were able to predict the SOA production to within a factor of 2 using a fuel-specific VOC emission inventory that was scaled by burn-specific toluene measurements. For fires of coniferous fuels that were dominated by needle burning, volatile biogenic compounds were the dominant precursor class. For wiregrass fires, furans were the dominant SOA precursors. We used a POA tracer ion to calculate the amount of mass lost due to gas-phase oxidation and subsequent volatilization of semivolatile POA. Less than 5% of the POA mass was lost via multiphase oxidation-driven evaporation during up to 2 hr of equivalent atmospheric oxidation

    Diagnostic for Verifying the Thrust Vector Requirement of the AEPS Hall-Effect Thruster and Comparison to the NEXT-C Thrust Vector Diagnostic

    Get PDF
    A diagnostic has been designed and fabricated to verify the thrust vector requirement for the Advanced Electric Propulsion System (AEPS) Hall Effect Rocket with Magnetic Shielding (HERMeS) thruster. This diagnostic will be used to verify that the propulsion system thrust vector offset from the mounting surface normal vector does not exceed 1.5 degrees over the entire throttling range and over the course of 23,000 hours of thruster testing. The diagnostic will also not violate the thruster's required voltage standoff capability in the presence of carbon backsputter by being minimally intrusive and not significantly adding to the facility backsputtered rate. Based on these requirements, an appropriate diagnostic design was determined to comprise of an array of 23 Faraday probes swept through the plume in an arc 1m from the thruster to map the beam current density. The beam current density centroid of the plume is assumed to track the thrust vector within an acceptable level of uncertainty. Additionally, a reference system, including optical alignment to the mounting surface normal vector and tilt sensors, was devised to periodically calibrate the probe position and motion throughout the long duration wear test campaign. Initial measurements of the thruster plume have been acquired to demonstrate the diagnostics functionality, verify procedures, and assess any necessary improvements prior to implementation of the diagnostic during the AEPS Engineering Development Unit (EDU) long duration wear test. To illustrate the merits of differing approaches to thrust vector determination for different classes of electric propulsion thrusters, NASA's Evolutionary Xenon Thruster-Commercial (NEXT-C) thrust vector diagnostic design details and recent data are also discussed (Appendix A)

    Underestimating calorie content when healthy foods are present: an averaging effect or a reference-dependent anchoring effect?

    Get PDF
    OBJECTIVE: Previous studies have shown that estimations of the calorie content of an unhealthy main meal food tend to be lower when the food is shown alongside a healthy item (e.g. fruit or vegetables) than when shown alone. This effect has been called the negative calorie illusion and has been attributed to averaging the unhealthy (vice) and healthy (virtue) foods leading to increased perceived healthiness and reduced calorie estimates. The current study aimed to replicate and extend these findings to test the hypothesized mediating effect of ratings of healthiness of foods on calorie estimates. METHODS: In three online studies, participants were invited to make calorie estimates of combinations of foods. Healthiness ratings of the food were also assessed. RESULTS: The first two studies failed to replicate the negative calorie illusion. In a final study, the use of a reference food, closely following a procedure from a previously published study, did elicit a negative calorie illusion. No evidence was found for a mediating role of healthiness estimates. CONCLUSION: The negative calorie illusion appears to be a function of the contrast between a food being judged and a reference, supporting the hypothesis that the negative calorie illusion arises from the use of a reference-dependent anchoring and adjustment heuristic and not from an 'averaging' effect, as initially proposed. This finding is consistent with existing data on sequential calorie estimates, and highlights a significant impact of the order in which foods are viewed on how foods are evaluated

    Diagnostic for Verifying the Thrust Vector Requirement of the AEPS Hall-Effect Thruster and Comparison to the NEXT-C Thrust Vector Diagnostic

    Get PDF
    A diagnostic has been designed and fabricated to verify the thrust vector requirement for the Advanced Electric Propulsion System (AEPS) Hall Effect Rocket with Magnetic Shielding (HERMeS) thruster. This diagnostic will be used to verify that the propulsion system thrust vector offset from the mounting surface normal vector does not exceed 1.5 degrees over the entire throttling range and over the course of 23,000 hours of thruster testing. The diagnostic will also not violate the thruster's required voltage standoff capability in the presence of carbon backsputter by being minimally intrusive and not significantly adding to the facility backsputtered rate. Based on these requirements, an appropriate diagnostic design was determined to comprise of an array of 23 Faraday probes swept through the plume in an arc 1m from the thruster to map the beam current density. The beam current density centroid of the plume is assumed to track the thrust vector within an acceptable level of uncertainty. Additionally, a reference system, including optical alignment to the mounting surface normal vector and tilt sensors, was devised to periodically calibrate the probe position and motion throughout the long duration wear test campaign. Initial measurements of the thruster plume have been acquired to demonstrate the diagnostics functionality, verify procedures, and assess any necessary improvements prior to implementation of the diagnostic during the AEPS Engineering Development Unit (EDU) long duration wear test. To illustrate the merits of differing approaches to thrust vector determination for different classes of electric propulsion thrusters, NASA's Evolutionary Xenon Thruster-Commercial (NEXT-C) thrust vector diagnostic design details and recent data are also discussed (Appendix A)

    Priming healthy eating. You can't prime all the people all of the time.

    Get PDF
    OBJECTIVE: In the context of a food purchasing environment filled with advertising and promotions, and an increased desire from policy makers to guide individuals toward choosing healthier foods, this study tests whether priming methods that use healthy food adverts to increase preference for healthier food generalize to a representative population. METHODS: In two studies (Study 1 n = 143; Study 2 n = 764), participants were randomly allocated to a prime condition, where they viewed fruit and vegetable advertisements, or a control condition, with no advertisements. A subsequent forced choice task assessed preference between fruits and other sweet snacks. Additional measures included current hunger and thirst, dietary restraint, age, gender, education and self-reported weight and height. RESULTS: In Study 1, hunger reduced preferences for fruits (OR (95% CI) = 0.38 (0.26-0.56), p <0.0001), an effect countered by the prime (OR (95% CI) = 2.29 (1.33-3.96), p = 0.003). In Study 2, the effect of the prime did not generalize to a representative population. More educated participants, as used in Study 1, chose more fruit when hungry and primed (OR (95% CI) = 1.42 (1.13-1.79), p = 0.003), while less educated participants' fruit choice was unaffected by hunger or the prime. CONCLUSION: This study provides preliminary evidence that the effects of adverts on healthy eating choices depend on key individual traits (education level) and states (hunger), do not generalize to a broader population and have the potential to increase health inequalities arising from food choice.We gratefully acknowledge the participation of all NIHR Cambridge BioResource (CBR) volunteers. We thank the Cambridge BioResource staff for their help with volunteer recruitment, members of the Cambridge BioResource SAB and Management Committee for their support of our study and the National Institute for Health Research Cambridge Biomedical Research Centre for funding. Access to CBR volunteers and their data and samples is governed by the CBR SAB. Documents describing access arrangements and contact details are available at http://www.cambridgebioresource.org.uk/. We are grateful to Chris Holmes and Sarah Walker for advice, comment and discussion on this work from a marketing perspective and to Graham Finlayson for use of the food images. The study was funded by the Department of Health Policy Research Program (Policy Research Unit in Behavior and Health [PR-UN-0409-10109]). The Department of Health had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.This is the final published version. It first appeared at http://dx.doi.org/10.1016/j.appet.2015.01.01

    Impact of weight maintenance and loss on diabetes risk and burden: a population-based study in 33,184 participants

    Get PDF
    Background\textbf{Background} Weight loss in individuals at high risk of diabetes is an effective prevention method and a major component of the currently prevailing diabetes prevention strategies. The aim of the present study was to investigate the public health potential for diabetes prevention of weight maintenance or moderate weight loss on a population level in an observational cohort with repeated measurements of weight and diabetes status. Methods\textbf{Methods} Height, weight and diabetes status were objectively measured at baseline and 10 year follow-up in a population-based cohort of 33,184 participants aged 30–60 years between 1990 and 2013 in Västerbotten County, Sweden. The association between risk of incident diabetes and change in BMI or relative weight was modelled using multivariate logistic regression. Population attributable fractions (PAF) were used to assess population impact of shift in weight. Results\textbf{Results} Mean (SD) BMI at baseline was 25.0 (3.6) kg/m2^2. Increase in relative weight between baseline and follow-up was linearly associated with incident diabetes risk, odds ratio (OR) 1.05 (95% confidence interval (CI) 1.04–1.06) per 1% change in weight. Compared to weight maintenance (±1.0 kg/m2^2), weight gain of >+1.0 kg/m2^2 was associated with an increased risk of incident diabetes, OR 1.52 (95% CI 1.32, 1.74), representing a PAF of 21.9% (95% CI 15.8, 27.6%). For moderate weight loss (−1.0 to −2.0 kg/m2^2) the OR was 0.72 (95% CI 0.52, 0.99). Conclusions\textbf{Conclusions} Weight maintenance in adulthood is strongly associated with reduced incident diabetes risk and there is considerable potential for diabetes prevention in promoting this as a whole population strategy.This work was supported by the Medical Research Council [MC_UU_12015/ 4], the Swedish Council for Working Life and Social Research [FAS 2006_1512] and the Swedish Research Council [2006-21576-36119-666]. The Västerbotten Intervention Programme is financed by Västerbotten County Council. Dr Feldman is supported by the Raymond and Beverly Sackler Foundation through Churchill College, Cambridge

    Coaxial metal and magnetic alloy nanotubes in polycarbonate templates by electroless deposition

    Get PDF
    We present a novel technique for the preparation of coaxial metal and magnetic alloy nanotubes, which is demonstrated for the coaxial nanotubes of Ni/Co and Ni/CoNiFe alloys deposited in activated polycarbonate templates using electroless plating. For each metal or alloy the tube wall thickness was controlled to be less than 100 nm. The process involved two consecutive deposition steps from hypophosphite and/or borane reducing agent based electroless plating solutions. We further characterise the magnetic properties of the ternary magnetic alloy films and coaxial nanotubes. The coaxial tubes show homogenous wall thickness and composition, which is delineated from the magnetic measurements
    • …
    corecore