2,042 research outputs found
Food security and regional integration in the SADC region
Bibliography: leaves 97-99.This thesis focuses on food security, policy and trade in the Southern African Development Community (SADC) region. Food security is rigorously defined, and its ideological foundations are examined. Because food security is so intricately linked to poverty and rural development, a discussion of the food security situation renders a study of the socio-economic situation in the SADC region necessary. Food security is not just an agricultural phenomenon, and thus policies to eradicate hunger have to be broad based as opposed to merely concentrating on increasing food production
Introduction to a Special Issue on the Impact of Immigrant Legalization Initiatives: International Perspectives on Immigration and the World of Work
This article is the third in a series to celebrate the 70th anniversary of the ILR Review. The series features articles that analyze the state of research and future directions for important themes the journal has featured over its many years of publication. In this issue, we also feature a special cluster of articles and book reviews on one of the most critical labor market issues across the globe—the legalization and integration of immigrants into national labor markets.
Despite the urgent need for immigration reform in the United States, there is a paucity of US research that looks at the impact of a shift from unauthorized to legal immigrant status in the workplace. The US immigration literature has also paid little attention to immigrant legalization policies outside of the United States, despite the fact that other countries have implemented such policies with far more regularity. The articles in this special issue draw on studies of legalization initiatives in major immigrant destinations: Canada, Italy, and the United Kingdom. Together they underscore the importance of cross-national perspectives for understanding the range of legalization programs and their impact on immigrant workers, the workplace, and the labor market. These findings contribute to key questions in migration scholarship and inform the global policy debate surrounding the integration and well-being of immigrant
When is a parasite not a parasite? Effects of larval tick burdens on white-footed mouse survival
Many animal species can carry considerable burdens of ectoparasites: parasites living on the outside of a host's body. Ectoparasite infestation can decrease host survival, but the magnitude and even direction of survival effects can vary depending on the type of ectoparasite and the nature and duration of the association. When ectoparasites also serve as vectors of pathogens, the effects of ectoparasite infestation on host survival have the potential to alter disease dynamics by regulating host populations and stabilizing transmission. We quantified the impact of larval Ixodes scapularis tick burdens on both within-season and overwinter survival of white-footed mice (Peromyscus leucopus) using a hierarchical Bayesian capture-mark-recapture model. I. scapularis and P. leucopus are, respectively, vectors and competent reservoirs for the causative agents of Lyme disease, anaplasmosis, and babesiosis. Using a data set of 5587 individual mouse capture histories over sixteen years, we found little evidence for any effect of tick burdens on either within-season or overwinter mouse survival probabilities. In male mice, tick burdens were positively correlated with within-season survival probabilities. Mean maximum tick burdens were also positively correlated with population rates of change during the concurrent breeding season. The apparent indifference of mice to high tick burdens may contribute to their effectiveness as reservoir hosts for several human zoonotic pathogens.Fil: Hersh, Michelle H.. Cary Institute of Ecosystem Studies; Estados Unidos. Bard College. Program in Biology; Estados Unidos. Sarah Lawrence College; Estados UnidosFil: LaDeau, Shannon L.. Cary Institute of Ecosystem Studies; Estados UnidosFil: Previtali, Maria Andrea. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias. Departamento de Ciencias Naturales; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Santa Fe; ArgentinaFil: Ostfeld, Richard S.. Cary Institute of Ecosystem Studies; Estados Unido
Testing the Subsistence Model for the Adoption of Ceramic Technology Among Coastal Sambaqui Foragers of Southern Brazil
This research tests the subsistence model for the adoption of ceramic technology among coastal fisher-hunter-gatherers of the southern Atlantic coast of Brazil (5000 to 600 BP). The subsistence model correlates the appearance of ceramic vessels at coastal sambaqui (shell mound) sites with changes in diet and/or food processing techniques. An alternative model, the prestige model, argues that prehistoric populations initially use pottery as status-bearing items in competitive feasting or as serving vessels for elite group members. To test the subsistence model, I conducted a stable carbon and nitrogen isotope analysis and a dental microwear texture analysis using skeletal remains from sambaqui sites located in Santa Catarina and Rio de Janeiro, Brazil.
The results of the stable carbon isotope analysis indicate no significant difference between Pre-Ceramic and Ceramic occupations when all individuals were considered. However, when only sexed individuals were considered, males of the Pre-Ceramic period show greater consumption of marine foods than Pre-Ceramic occupation females. This difference between males and females is not significant for the Ceramic period. Results of the nitrogen isotope analysis indicate a significant increase in the consumption of marine foods among all individuals during the Ceramic period compared to the Pre-Ceramic period.
The results of the dental microwear texture analysis indicate no significant difference between the Pre-Ceramic and Ceramic periods when all individuals were considered. However, Pre-Ceramic occupation males show significantly greater tooth enamel complexity (Asfc) than males of the Ceramic period. I found no statistically significant differences between time periods for anisotropy (epLsar); however, a plot containing epLsar measurements and nitrogen isotope ratios reveals a relationship between the data. Individuals from the Ceramic period tend to plot lower for measurements of anisotropy and higher for marine food consumption, while Pre-Ceramic occupation individuals plot higher for anisotropy and lower for marine food consumption.
This study partially supports the subsistence model for the adoption of ceramic technology at sambaqui sites, as tests show significant differences based on sex. However, there is room in the data to explore ideas related to changes in social and political organization with the arrival of ceramic technology at these sites
Oxygen content variation and cation doping dependence of (La)1.4(Sr1-yCay)1.6Mn2O7 (y = 0, 0.25, 0.5) bilayered manganites properties
The results of the synthesis and characterization of the optimally doped
(La)1.4(Sr1-yCay)1.6Mn2O7 solid solution with y=0, 0.25 and 0.5 are reported.
By progressively replacing the Sr with the smaller Ca, while keeping fixed the
hole-concentration due to the divalent dopant, the 'size effect' of the cation
itself on the structural, transport and magnetic properties of the bilayered
manganite has been analysed. Two different annealing treatments of the solid
solution, in pure oxygen and in pure argon, allowed also to study the effect of
the oxygen content variation. Structure and electronic properties of the
samples have been investigated by means of X-ray powder diffraction and X-ray
absorption spectroscopy measurements. Magnetoresistivity and static
magnetization measurements have been carried out to complete the samples
characterization. Oxygen annealing of the solid solution, that showed a limit
for about y=0.5, induces an increase of the Mn average valence state and a
transition of the crystal structure from tetragonal to orthorhombic while the
argon annealing induces an oxygen under-stoichiometry and, in turn, a reduction
of the Mn average valence state. Along with the Ca substitution, the
Jahn-Teller distortion of the MnO6 octahedra is reduced. This has been directly
connected to a general enhancement of the transport properties induced by the
Ca-doping. For the same cation composition, oxygen over-stoichiometry leads to
higher metal-insulator transition temperatures and lower resistivity values.
Curie temperatures (TC) reduce by increasing the Ca-doping. The lower TC for
all the annealed samples with respect to the 'as prepared' ones are connected
to the strong influence on the magnetic interaction of the point defects due to
the oxygen content variation.Comment: 49 pages, 13 figure
Focusing on Excessive Gestational Weight Gain through Weight Tracking Among Participants of the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) in Southern California
Background and Purpose: Studies have shown that maternal obesity and excessive gestational weight gain (GWG) lead to adverse health outcomes for the mother and her offspring. Yet, knowledge of the best way to intervene is still lacking. The objective of this study was to develop, pilot and evaluate a sustainable intervention to prevent excessive GWG among participants of the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) in southern California. Methods: We conducted a prospective cohort study where the intervention group received an individual education program that included a GWG tracker. The historical control group was a group of women from the same WIC site who gave birth before the start of the intervention, therefore did not receive the intervention. Chi-square tests and t-tests were used to compare characteristics of the control and intervention groups and the proportions of women exceeding the Institute of Medicine (IOM) recommendations for GWG. Results: The impact of the intervention was strongest for overweight women. 62.5% of the control group gained more than the recommended amount compared to 48.6% in the intervention group. Conclusion: A simple weight tracking intervention could be a cost-neutral way to help WIC participants avoid excessive GWG
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