393 research outputs found
Nutritional Consequences of Food Insecurity in a Rural New York State County
This study of women with children in a rural county of upstate New York examined the relationships of food insecurity and income with two nutritional consequences (adiposity and fruit and vegetables consumption), and assessed whether disordered eating patterns is a mediator for the effects of food insecurity and income on these nutritional consequences. Each of 193 respondents was interviewed twice in her home. Data were collected on household food stores, socioeconomic and demographic characteristics, methods of obtaining food, food program participation, household expenditures, food intake, the Radimer/Cornell hunger and food insecurity items, height, weight, frequency of fruit and vegetable consumption, and disordered eating patterns. Regression analysis was used to analyze the relationships of body mass index and an obesity classification with height, income, education, single parenthood, employment, food insecurity, disordered eating, and frequency of fruit and vegetable consumption. Regression analysis was also used to examine the relationships of disordered eating and frequency of fruit and vegetable consumption with the other variables. Lower income and unemployment were related to higher adiposity. The effects of income on adiposity were not mediated through disordered eating patterns or through fruit and vegetable consumption. Food insecurity was related to adiposity, and part of this effect of food insecurity was mediated through disordered eating. This mediating effect of disordered eating partially explained why those experiencing the least severe food insecurity were more likely to be overweight than those who were food secure, but those experiencing the most severe food insecurity were less likely to be overweight than those who were food secure. Food insecurity was related to lower fruit and vegetable consumption, but this did not translate into effects on adiposity.
Miniaturized Cassegrainian concentrator concept demonstration
High concentration ratio photovoltaic systems for space applications have generally been considered impractical because of perceived difficulties in controlling solar cell temperatures to reasonably low values. A miniaturized concentrator system is now under development which surmounts this objection by providing acceptable solar cell temperatures using purely passive cell cooling methods. An array of identical miniaturized, rigid Cassegrainian optical systems having a low f-number with resulting short dimensions along their optical axes are rigidly mounted into a frame to form a relatively thin concentrator solar array panel. A number of such panels, approximately 1.5 centimeters thick, are wired as an array and are folded against one another for launch in a stowed configuration. Deployment on orbit is similar to the deployment of conventional planar honeycomb panel arrays or flexible blanket arrays. The miniaturized concept was conceived and studied in the 1978-80 time frame. Progress in the feasibility demonstration to date is reported
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Glancing angle deposition of sculptured thin metal films at room temperature
Metallic thin films consisting of separated nanostructures are fabricated by evaporative glancing angle deposition at room temperature. The columnar microstructure of the Ti and Cr columns is investigated by high resolution transmission electron microscopy and selective area electron diffraction. The morphology of the sculptured metallic films is studied by scanning electron microscopy. It is found that tilted Ti and Cr columns grow with a single crystalline morphology, while upright Cr columns are polycrystalline. Further, the influence of continuous substrate rotation on the shaping of Al, Ti, Cr and Mo nanostructures is studied with view to surface diffusion and the shadowing effect. It is observed that sculptured metallic thin films deposited without substrate rotation grow faster compared to those grown with continuous substrate rotation. A theoretical model is provided to describe this effect
Estimating the prevalence of hunger and food insecurity: The validity of questionnaire-based measures for the identification of households
This study had three objectives: (1) to assess the validity of questionnaire-based measures in identifying households experiencing hunger and food insecurity, (2) to examine the interrelationships of different questionnaire-based measures, and (3) to examine the construction of a continuous food insecurity scale intended to differentiate three levels of food insecurity within households. A 1993 survey of 193 randomly sampled rural households with women and children living at home provided data on demographics, risk factors for food insecurity, Radimer/Cornell, CCHIP, and NHANES III hunger and food insecurity items, coping strategies, fruit and vegetable consumption, disordered eating behaviors, height, weight, dietary recall, and household food-stores inventory. This information was used to develop a definitive criterion measure for hunger and food insecurity, against which the Radimer/Cornell and CCHIP questionnaire-based measures, the NHANES III item, and the continuous food insecurity scale were tested for their specificity and sensitivity in measuring levels of food insecurity.
Glancing angle deposition of sculptured thin metal films at room temperature
Metallic thin films consisting of separated nanostructures are fabricated by evaporative glancing
angle deposition at room temperature. The columnar microstructure of the Ti and Cr columns is
investigated by high resolution transmission electron microscopy and selective area electron
diffraction. The morphology of the sculptured metallic films is studied by scanning electron
microscopy. It is found that tilted Ti and Cr columns grow with a single crystalline morphology,
while upright Cr columns are polycrystalline. Further, the influence of continuous substrate
rotation on the shaping of Al, Ti, Cr and Mo nanostructures is studied with view to surface
diffusion and the shadowing effect. It is observed that sculptured metallic thin films deposited
without substrate rotation grow faster compared to those grown with continuous substrate
rotation. A theoretical model is provided to describe this effec
Analysis of planetary analogue materials by laser-induced breakdown spectroscopy
Laser Induced Breakdown Spectroscopy (LIBS) is a promising tool for elemental chemical analysis in planetary science, because it allows real-time and fast in-situ determination of the elemental composition of materials down to minute concentrations. The technique requires no special preparation of samples, can provide high lateral resolution (as low as several tenths ÎŒm), depth profiling (down to mm) and, therefore, is not disturbed by dust layers. Miniaturized LIBS instruments are currently considered for the next NASA (Mars Science Laboratory) and ESA (ExoMars) missions to Mars, as well as studied for the international Europa Lander Mission. Here we present the LIBS laboratory facility at the German Aerospace Center in Berlin for the chemical elemental analysis under simulated planetary (Mars, Europa) conditions. The main purpose of the system is the study of the LIBS capability for in-situ spectroscopy for diverse planetary missions as well as the development of a LIBS spectral database under simulated planetary conditions for planetary analogue materials
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Highly sensitive and specific detection of E. coli by a SERS nanobiosensor chip utilizing metallic nanosculptured thin films
A nanobiosensor chip, utilizing surface enhanced Raman spectroscopy (SERS) on nanosculptured thin films (nSTFs) of silver, was shown to detect Escherichia coli (E. coli) bacteria down to the concentration level of a single bacterium. The sensor utilizes highly enhanced plasmonic nSTFs of silver on a silicon platform for the enhancement of Raman bands as checked with adsorbed 4-aminothiophenol molecules. T-4 bacteriophages were immobilized on the aforementioned surface of the chip for the specific capture of target E. coli bacteria. To demonstrate that no significant non-specific immobilization of other bacteria occurs, three different, additional bacterial strains, Chromobacterium violaceum, Paracoccus denitrificans and Pseudomonas aeruginosa were used. Furthermore, experiments performed on an additional strain of E. coli to address the specificity and reusability of the sensor showed that the sensor operates for different strains of E. coli and is reusable. Time resolved phase contrast microscopy of the E. coli-T4 bacteriophage chip was performed to study its interaction with bacteria over time. Results showed that the present sensor performs a fast, accurate and stable detection of E. coli with ultra-small concentrations of bacteria down to the level of a single bacterium in 10 ÎŒl volume of the sample
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Preparation and characterisation of carbon-free Cu(111) films on sapphire for graphene synthesis
This work presents an investigation of carbon formed on polycrystalline Cu(111) thin films prepared by ion beam sputtering at room temperature on c-plane Al2O3 after thermal treatment in a temperature range between 300 and 1020°C. The crystallinity of the Cu films was studied by XRD and RBS/channeling and the surface was characterised by Raman spectroscopy, XPS and AFM for each annealing temperature. RBS measurements revealed the diffusion of the Cu into the Al2O3 substrate at high temperatures of > 700°C. Furthermore, a cleaning procedure using UV ozone treatment is presented to remove the carbon from the surface which yields essentially carbon-free Cu films that open the possibility to synthesize graphene of well-controlled thickness (layer number)
A hydrodynamically optimized nano-electrospray ionization source and vacuum interface
The coupling of atmospheric pressure ionization (API) sources like electrospray ionization (ESI) to vacuum based applications like mass spectrometry (MS) or ion beam deposition (IBD) is done by differential pumping, starting with a capillary or pinhole inlet. Because of its low ion transfer efficiency the inlet represents a major bottleneck for these applications. Here we present a nano-ESI vacuum interface optimized to exploit the hydrodynamic drag of the background gas for collimation and the reduction of space charge repulsion. Up to a space charge limit of 40 nA we observe 100% current transmission through a capillary with an inlet and show by MS and IBD experiments that the transmitted ion beams are well defined and free of additional contamination compared to a conventional interface. Based on computational fluid dynamics modelling and ion transport simulations, we show how the specific shape enhances the collimation of the ion cloud. Mass selected ion currents in the nanoampere range available further downstream in high vacuum open many perspectives for the efficient use of electrospray ion beam deposition (ES-IBD) as a surface coating method
Review and Prospects of PEM Water Electrolysis at Elevated Temperature Operation
Polymer electrolyte membrane water electrolyzers (PEMWE) are currently restricted to an operating temperature range between 50 to 80 °C. This review shows that elevated temperature (ET) above 90 °C can be advantageous with respect to i) reduced cell voltages, ii) a reduction of catalyst loading or possibly the employment of less noble electrocatalysts, and iii) a greater potential for waste heat utilization when the electrolyzer is operated in exothermal mode (when the cell voltage is higher than the thermoneutral voltage). Together with presenting an overview of the materials and components utilized in elevated temperature PEMWE under liquid and steam operation, this article summarizes the experimental and modeling performances reported to date, highlights the challenges ahead, and suggests aspects, which will need to be considered to improve the performance at elevated temperature. Key points, which arise from this work are the extensive need of re-assessing the material selection both for the cell components and also at a system level, the effects and optimization of working with steam operation, and in the long run, the need for techno-economic analyses to ultimately assess whether efficiency gains will truly translate to a cost-effective technology alternative
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