1,054 research outputs found
Reducing the Variability and Cost of Determining the Coefficient of Friction of Various Lubricants
The Navy requires accurate fastener preloading for many of its fastened applications to protect the safety of the vessel and its personnel, and to ensure proper operation of various components. The preload is based on many properties including fastener materials, fastener geometries, and the coefficient of friction (COF) between mating surfaces. The COF is a critical value in determining the torque-load relationship of a fastener, and is dependent on the contact surface area and the materials in contact, the condition and finish of the contact surfaces, and any lubricant applied in these contact areas. Due to the large amount of variables in a joint, the COF of any particular lubricant must be determined empirically via a time and resource intensive testing regime that tests over 250 individual fastener assemblies. For the Navy, the lubricants that currently have known COF values are expensive, difficult to procure, or lack other favorable properties such as washout resistance or the ability to be used in a diver-safe environment. Portsmouth Naval Shipyard (PNSY) has tasked me with optimizing their existing procedure to require less time and resources, and to improve the process to make it safer and more efficient
The Relative Importance of Search versus Credence Product Attributes: Organic and Locally Grown
Organic foods and local foods have come to the forefront of consumer issues, due to concerns about nutrition, health, sustainability, and food safety. A conjoint analysis experiment quantified the relative importance of, and trade-offs between, apple search and experience attributes (quality/blemishes, size, flavor), credence attributes (conventional vs. organic production method, local origin vs. product of USA vs. imported), and purchase price when buying apples. Quality is the most important apple attribute. Production methodââŹâorganic versus conventionalââŹâhad no significant impact on preferences.conjoint analysis, organic, locally grown, credence attributes, Consumer/Household Economics, Food Consumption/Nutrition/Food Safety, Marketing,
Selenium-mediated synthesis of tetrasubstituted naphthalenes through rearrangement
New β-keto ester substituted stilbene derivatives have been synthesized and cyclized with selenium electrophiles in the presence of Lewis acids. This now allows access to 1,2,3,4-tetrasubstituted naphthalene derivatives as cyclization and rearrangement products
Lower Dietary Inflammatory Index Scores Are Associated with Lower Glycemic Index Scores among College Students
The association between the Dietary Inflammatory Index (DIIÂŽ), the glycemic index (GI), and the glycemic load (GL) is not known, although it is known that carbohydrates are pro-inflammatory. We aimed to measure the association between the DII and both GI and GL among college students. In this cross-sectional study, 110 college students completed a 3-day food diary, which was used to calculate the DII, the GI, the GL, and the healthy eating index (HEI)-2010. Least square means and 95% confidence intervals of the GI, the GL, and the HEI-2010 were presented per DII tertile using generalized linear mixed models. Participants in tertile 1 of DII scores had lower GI and GL scores, but higher HEI-2010 scores than those in tertile 3. Pearson correlations showed that DII score was positively correlated with the GI score (r = 0.30, p \u3c 0.01), but negatively correlated with the HEI-2010 (r = â0.56, p \u3c 0.001). DII score was not correlated with GL score. Results from this study suggest that increased inflammatory potential of diet, as represented by higher DII scores, was associated with increased GI scores and lower quality of diet on the HEI-2010. Use of the DII suggests new directions for dietary approaches for preventing chronic diseases that moves beyond convention by decreasing systemic inflammation
The relationship of plasma Trans fatty acids with dietary inflammatory index among US adults
BACKGROUND: It has been suggested that trans fatty acids (TFAs) play an important role in cardiovascular diseases. We investigated the association between plasma TFAs and the dietary inflammatory index (DII) ⢠in US adults. METHODS: National Health and Nutrition Examination Survey (NHANES) participants with data on plasma TFAs measured from 1999 to 2010 were included. Energy-adjusted-DII ⢠(E-DII â˘) expressed per 1000 kcal was calculated from 24-h dietary recalls. All statistical analyses accounted for the survey design and sample weights. RESULTS: Of the 5446 eligible participants, 46.8% (n = 2550) were men. The mean age of the population was 47.1 years overall, 47.8 years for men and 46.5 years for women (p = 0.09). After adjustment for C-reactive protein, body-mass-index, smoking, race, age, education, and marital status in linear regressions, trans 9-hexadecenoic acid [β coefficient 0.068 (95% CI: 0.032 to 0.188)], trans 11-octadecenoic acid [β coefficient 0.143 (95% CI: 0.155 to 0.310)], trans 9-octadecenoic acid [β coefficient 0.122 (95% CI: 0.120 to 0.277)], trans 9, and trans 12-octadienoic acid [β coefficient 0.103 (95% CI: 0.090 to 0.247)] were positively associated with the DII (all p < 0.001). CONCLUSION: The association of plasma TFAs with a marker of dietary inflammation suggests an underlying mechanism in the initiation and progression of cardiovascular diseases
Quantifying Exceptionally Large Populations of \u3ci\u3eAcropora\u3c/i\u3e spp. Corals Off Belize Using Sub-Meter Satellite Imagery Classification
Caribbean coral reefs have experienced dramatic declines in live coral cover in recent decades. Primary branching framework Caribbean corals, Acropora cervicornis (Lamarck, 1816) and Acropora palmata (Lamarck, 1816), have suffered the greatest collapse. Coral Gardens, Belize, is one of few remaining, and perhaps the largest, refugia for abundant, healthy, but undocumented populations of both Acropora species in the Caribbean Sea. In the present study, GeoEye-1 multispectral satellite imagery of a 25 km2 reefal area near Ambergris Caye, Belize, was analyzed to identify live Acropora spp. cover. We used a supervised classification to predict occurrence of areas with live Acropora spp. and to separate them from other benthic cover types, such as sandy bottom, seagrass, and mixed massive coral species. We tested classification accuracy in the field, and new Acropora spp. patches were mapped using differential GPS. Of 11 predicted new areas of Acropora spp., eight were composed of healthy Acropora spp. An unsupervised classification of a red (Band 3):blue (Band 1) ratio calculation of the image successfully separated Acropora corals from other benthic cover, with an overall accuracy of 90%. Our study identified 7.58 ha of reef dominated by Acropora spp. at Coral Gardens, which is one of the largest populations in the Caribbean Sea. We suggest that Coral Gardens may be an important site for the study of modern Acropora spp. resilience. Our technique can be used as an efficient tool for genera-specific identification, monitoring, and conservation of populations of endangered Acropora spp
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Predictors of anemia in preschool children: Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) project.
Background: A lack of information on the etiology of anemia has hampered the design and monitoring of anemia-control efforts.Objective: We aimed to evaluate predictors of anemia in preschool children (PSC) (age range: 6-59 mo) by country and infection-burden category.Design: Cross-sectional data from 16 surveys (n = 29,293) from the Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) project were analyzed separately and pooled by category of infection burden. We assessed relations between anemia (hemoglobin concentration <110 g/L) and severe anemia (hemoglobin concentration <70 g/L) and individual-level (age, anthropometric measures, micronutrient deficiencies, malaria, and inflammation) and household-level predictors; we also examined the proportion of anemia with concomitant iron deficiency (defined as an inflammation-adjusted ferritin concentration <12 Îźg/L). Countries were grouped into 4 categories on the basis of risk and burden of infectious disease, and a pooled multivariable logistic regression analysis was conducted for each group.Results: Iron deficiency, malaria, breastfeeding, stunting, underweight, inflammation, low socioeconomic status, and poor sanitation were each associated with anemia in >50% of surveys. Associations between breastfeeding and anemia were attenuated by controlling for child age, which was negatively associated with anemia. The most consistent predictors of severe anemia were malaria, poor sanitation, and underweight. In multivariable pooled models, child age, iron deficiency, and stunting independently predicted anemia and severe anemia. Inflammation was generally associated with anemia in the high- and very high-infection groups but not in the low- and medium-infection groups. In PSC with anemia, 50%, 30%, 55%, and 58% of children had concomitant iron deficiency in low-, medium-, high-, and very high-infection categories, respectively.Conclusions: Although causal inference is limited by cross-sectional survey data, results suggest anemia-control programs should address both iron deficiency and infections. The relative importance of factors that are associated with anemia varies by setting, and thus, country-specific data are needed to guide programs
Global congruence of carbon storage and biodiversity in terrestrial ecosystems
Deforestation is a main driver of climate change and biodiversity loss. An incentive mechanism to reduce emissions from deforestation and forest degradation (REDD) is being negotiated under the United Nations Framework Convention on Climate Change. Here we use the best available global data sets on terrestrial biodiversity and carbon storage to map and investigate potential synergies between carbon and biodiversity-oriented conservation. A strong association (rS= 0.82) between carbon stocks and species richness suggests that such synergies would be high, but unevenly distributed. Many areas of high value for biodiversity could be protected by carbon-based conservation, while others could benefit from complementary funding arising from their carbon content. Some high-biodiversity regions, however, would not benefit from carbon-focused conservation, and could become under increased pressure if REDD is implemented. Our results suggest that additional gains for biodiversity conservation are possible, without compromising the effectiveness for climate change mitigation, if REDD takes biodiversity distribution into account
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