1,175 research outputs found

    The Homeric and Hesiodic conception of the universe

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    Abstract taken from the Introduction section of the thesis: The chief purpose of this paper is to give a full account of the Homeric and Hesiodic ideas of the different parts of the universe, the main sources of information being the Iliad and Odyssey of Homer, the Theogony of Hesiod, the Homeric hymns, and Apollodorus

    Modeling the role of voyaging in the coastal spread of the Early Neolithic in the West Mediterranean

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    The earliest dates for the West Mediterranean Neolithic indicate that it expanded across 2,500 km in about 300 y. Such a fast spread is held to be mainly due to a demic process driven by dispersal along coastal routes. Here, we model the Neolithic spread in the region by focusing on the role of voyaging to understand better the core elements that produced the observed pattern of dates. We also explore the effect of cultural interaction with Mesolithic populations living along the coast. The simulation study shows that (i) sea travel is required to obtain reasonable predictions, with a minimum sea-travel range of 300 km per generation; (ii) leapfrog coastal dispersals yield the best results (quantitatively and qualitatively); and (iii) interaction with Mesolithic people can assist the spread, but long-range voyaging is still needed to explain the archaeological pattern.info:eu-repo/semantics/publishedVersio

    Plant community and tissue chemistry responses to fertilizer and litter nutrient manipulations in a temperate grassland

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    Human-mediated nutrient amendments have widespread effects on plant communities. One of the major consequences has been the loss of species diversity under increased nutrient inputs. The loss of species can be functional group dependent with certain functional groups being more prone to decline than others. We present results from the sixth year of a long-term fertilization and litter manipulation study in an old-field grassland. We measured plant tissue chemistry (C:N ratio) to understand the role of plant physiological responses in the increase or decline of functional groups under nutrient manipulations. Fertilized plots had significantly more total aboveground biomass and live biomass than unfertilized plots, which was largely due to greater productivity by exotic C3 grasses. We found that both fertilization and litter treatments affected plant species richness. Species richness was lower on plots that were fertilized or had litter intact; species losses were primarily from forbs and non-Poaceae graminoids. C3 grasses and forbs had lower C:N ratios under fertilization with forbs having marginally greater %N responses to fertilization than grasses. Tissue chemistry in the C3 grasses also varied depending on tissue type with reproductive tillers having higher C:N ratios than vegetative tillers. Although forbs had greater tissue chemistry responses to fertilization, they did not have a similar positive response in productivity and the number of forb species is decreasing on our experimental plots. Overall, differential nutrient uptake and use among functional groups influenced biomass production and species interactions, favoring exotic C3 grasses and leading to their dominance. These data suggest functional groups may differ in their responses to anthropogenic nutrient amendments, ultimately influencing plant community composition

    Tracing the Origin and Spread of Agriculture in Europe

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    The origins of early farming and its spread to Europe have been the subject of major interest for some time. The main controversy today is over the nature of the Neolithic transition in Europe: the extent to which the spread was, for the most part, indigenous and animated by imitation (cultural diffusion) or else was driven by an influx of dispersing populations (demic diffusion). We analyze the spatiotemporal dynamics of the transition using radiocarbon dates from 735 early Neolithic sites in Europe, the Near East, and Anatolia. We compute great-circle and shortest-path distances from each site to 35 possible agricultural centers of origin—ten are based on early sites in the Middle East and 25 are hypothetical locations set at 5° latitude/longitude intervals. We perform a linear fit of distance versus age (and vice versa) for each center. For certain centers, high correlation coefficients (R > 0.8) are obtained. This implies that a steady rate or speed is a good overall approximation for this historical development. The average rate of the Neolithic spread over Europe is 0.6–1.3 km/y (95% confidence interval). This is consistent with the prediction of demic diffusion (0.6–1.1 km/y). An interpolative map of correlation coefficients, obtained by using shortest-path distances, shows that the origins of agriculture were most likely to have occurred in the northern Levantine/Mesopotamian area

    Serving Breakfast Free to All Students and Type of Breakfast Serving Model Are Associated with Participation in the School Breakfast Program

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    Background: Many students experience challenges participating in the School Breakfast Program (SBP) when breakfast is served before school in the cafeteria. Serving breakfast free to all students or offering innovative breakfast serving models, such as breakfast in the classroom (BIC), grab n’ go, or second chance breakfast, may encourage higher SBP participation rates. Objective: To examine the association between offering breakfast free to all students as well as breakfast serving model with student participation in the SBP in October 2017 among public schools in North Carolina. Design: Cross-sectional study using data from the North Carolina Department of Public Instruction. Participants/setting: This study included data from 2,285 North Carolina public schools who served breakfast in October 2017 with 1,445,287 students. Main outcome measures: The main outcome measures are the odds of a student participating in the SBP among students overall, students eligible for free or reduced-price (FRP) meals, and students not eligible for FRP meals. Statistical analyses performed: Multiple logistic regression assessed the association between offering breakfast free to all students and breakfast serving model with the probability of participating in the SBP (number of students participating out of number of students enrolled) for students overall, eligible for FRP meals, and not eligible for FRP meals. Statistical models were stratified by school type (elementary, middle, and high schools). Results: Breakfast serving models positively associated with SBP participation were BIC and BIC plus grab n’ go for elementary and high school students and grab n’ go and second chance for middle and high school students (P<0.05). Serving breakfast free to all students was positively associated with SBP participation alone and in combination with BIC, second chance, and BIC plus grab n’ go (P<0.05). Conclusions: Serving breakfast free to all students and breakfast serving model were associated with SBP participation, and different relationships existed for different school levels

    Marginal, Low, and Very-Low Food Security among Children Are Associated with Intake of Select Dietary Factors during Summer

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    Background: School meals are associated with improved food security status and dietary intake. Children receiving free and reduced-price school meals lose access to these meals during the summer. The association between food security status and dietary intake in these children during summer is unclear. Objective: To examine the association between food security status (high, marginal, low, and very-low food security) among children and intake of select dietary factors during summer in children certified for free and reduced-price school meals by age group (3 to 4 years, 5 to 8 years, 9 to 12 years, and 13 to 17 years). Design: Cross-sectional analysis. Participants/setting: Secondary data from 11,873 children aged 3 to 17 years in the control group of the US Department of Agriculture Summer Electronic Benefit Transfer for Children Demonstration Project. Main outcome measures: Consumption of total fruits and vegetables; fruits and vegetables, excluding fried potatoes; whole grains; added sugars; added sugars, excluding cereals; added sugars from sugar-sweetened beverages; and dairy products assessed using questions from the 2009-2010 National Health and Nutrition Examination Survey Multifactor Diet Screener. Statistical analysis: Multiple linear regression. Results: For the majority of age groups, marginal food security, low food security, and very-low food security were associated with lower fruit and vegetable consumption and low food security and very-low food security were associated with lower dairy consumption, with children from households with very-low food security having the lowest consumption. Children from households with very-low food security consumed 0.73 (95% CI –0.93 to –0.53) to 0.99 (95% CI –1.59 to –0.39) cup equivalents less per day of fruits and vegetables and 0.49 (95% CI –0.65 to –0.34) to 0.68 (95% CI –1.07 to –0.29) cup equivalents less per day of dairy compared with children from households experiencing high food security. Conclusions: Lower food security was associated with reduced consumption of fruits and vegetables and dairy products during summer in children from low-income households

    Predictors and outcomes of excess gestational weight gain among low-income pregnant women

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    Low-income women were interviewed and their post-natal records were retrieved (n = 160) to assess prevalence of excess gestational weight gain and its socio-demographic predictors. More than half of the women (64%) gained excess weight during pregnancy, with an average of 10 lbs in excess of Institute of Medicine guidelines. Logistic regression indicated that women that started pregnancy at an obese body mass index; who were African American or having an unplanned pregnancy were at significant risk of gaining excess weight in pregnancy. Intervention to prevent excess weight gain during pregnancy is critical in addressing obesity epidemic in the United States and worldwide

    Louse- and flea-borne rickettsioses: biological and genomic analyses

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    In contrast to 15 or more validated and/or proposed tick-borne spotted fever group species, only three named medically important rickettsial species are associated with insects. These insect-borne rickettsiae are comprised of two highly pathogenic species, Rickettsia prowazekii (the agent of epidemic typhus) and R. typhi (the agent of murine typhus), as well as R. felis, a species with unconfirmed pathogenicity. Rickettsial association with obligate hematophagous insects such as the human body louse (R. prowazekii transmitted by Pediculus h. humanus) and several flea species (R. typhi and R. felis, as well as R. prowazekii in sylvatic form) provides rickettsiae the potential for further multiplications, longer transmission cycles and rapid spread among susceptible human populations. Both human body lice and fleas are intermittent feeders capable of multiple blood meals per generation, facilitating the efficient transmission of rickettsiae to several disparate hosts within urban/rural ecosystems. While taking into consideration the existing knowledge of rickettsial biology and genomic attributes, we have analyzed and summarized the interacting features that are unique to both the rickettsiae and their vector fleas and lice. Furthermore, factors that underlie rickettsial changing ecology, where native mammalian populations are involved in the maintenance of rickettsial cycle and transmission, are discussed

    Food Policy Council Self-Assessment Tool: Development, Testing, and Results

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    A large number of food policy councils (FPCs) exist in the United States, Canada, and Tribal Nations (N = 278), yet there are no tools designed to measure their members' perceptions of organizational capacity, social capital, and council effectiveness. Without such tools, it is challenging to determine best practices for FPCs and to measure change within and across councils over time. This study describes the development, testing, and findings from the Food Policy Council Self-Assessment Tool (FPC-SAT). The assessment measures council practices and council members' perceptions of the following concepts: leadership, breadth of active membership, council climate, formality of council structure, knowledge sharing, relationships, member empowerment, community context, synergy, and impacts on the food system. All 278 FPCs listed on the Food Policy Network's Online Directory were recruited to complete the FPC-SAT. Internal reliability (Cronbach's α) and inter-rater reliability (AD, rWG(J), ICC [intraclass correlations][1], ICC[2]) were calculated, and exploratory and a confirmatory factor analyses were conducted. Responses from 354 FPC members from 94 councils were used to test the assessment. Cronbach's α ranged from 0.79 to 0.93 for the scales. FPC members reported the lowest mean scores on the breadth of active membership scale (2.49; standard deviation [SD], 0.62), indicating room for improvement, and highest on the leadership scale (3.45; SD, 0.45). The valid FPC-SAT can be used to identify FPC strengths and areas for improvement, measure differences across FPCs, and measure change in FPCs over time
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