1,330 research outputs found

    Land tenure and the adoption of agricultural technology in Haiti:

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    There has long been an active debate in Haiti - as in many other developing countries - over whether or not the customary tenure system constrains technology adoption and agricultural development, and whether cadaster and land titling should be national priorities. This paper contributes to this debate by reviewing and interpreting the body of literature and new empirical evidence concerning the relationship between land tenure and the adoption of technology in rural Haiti. The findings suggest that (a) formal title is not necessarily more secure than informal arrangements, (b) informal arrangements based on traditional social capital resources assure affordable and flexible access to land for most people, and (c) perceived stability of access to land-via stability of personal and social relationships-is a more important determinant of technology adoption than mode of access. The paper concludes that there is no definitive relationship between tenure and technology adoption by peasants; peasants are preoccupied more by political and economic insecurity than insecure tenure; and rather than tinkering with formalizing tenure, policy makers should prioritize other more fundamental rural sector reforms. The paper ends by considering some of the implications for theory and suggests several avenues for future research on land policy.

    Computational Methods and Results for Structured Multiscale Models of Tumor Invasion

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    We present multiscale models of cancer tumor invasion with components at the molecular, cellular, and tissue levels. We provide biological justifications for the model components, present computational results from the model, and discuss the scientific-computing methodology used to solve the model equations. The models and methodology presented in this paper form the basis for developing and treating increasingly complex, mechanistic models of tumor invasion that will be more predictive and less phenomenological. Because many of the features of the cancer models, such as taxis, aging and growth, are seen in other biological systems, the models and methods discussed here also provide a template for handling a broader range of biological problems

    AN AUSTRONESIAN PRESENCE IN SOUTHERN JAPAN: EARLY OCCUPATION IN THE YAEYAMA ISLANDS.

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    Archaeological research in the Yaeyama Islands, southern Japan, has a hundred year old history, yet little of it is known to those archaeologists working outside the immediate area. This area is of importance to those working in Southeast Asia and the Pacific as the colonisation of the Yaeyama Islands allows a closer assessment of the nature and timing of Austronesian movement out of Taiwan. This paper will examine the colonisation of the Yaeyama Islands and its archaeological signature, Shimotabaru pottery, by first reviewing the archaeological developments of this island group, followed by an examination of the timing of colonisation and the nature of Shimotabaru pottery production. It will be argued that the early occupation in the Yaeyama Islands characterised by Shimotabaru pottery is the signature of Austronesian colonisation from Taiwan, from between 4500 and 3900 years ago. Yet the colonising signature in the Yaeyama Islands is of a different character to the Austronesian presence in the islands south of Taiwan. This suggests that the nature of Austronesian expansion in general was more complex than is proposed in the prevailing model

    Proceedings of the 19th Annual Meeting, Southern Soybean Disease Workers (February 19-20, 1992, St. Louis, Missouri)

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    Contents Southern Soybean Disease Workers 1991-1992 officers 1991-1992 Program Committee Graduate student competition Interactions of Macrophomina phaseolina with two soybean cultivars under four irrigation regimes. SR Kendig and JC Rupe Influence of soybean planting dates on the incidence and severity of Sudden Death Syndrome. SS Alghamdi, PT Gibson, and MA Shenaut The interrelationship of Heterodera glycines and Fusarium solani in sudden death syndrome of soybean. KS McLean and GW Lawrence Frogeye leaf spot of soybean: evaluation of cultivars and isolates. PF Pace, DB Weaver, and LD Ploper Soybean cyst nematode race symposium SCN race scheme: a historical perspective. JA Fox Races of Heterodera glycines: a nematological perspective. TL Niblack Races of Heterodera glycines and level of resistance in soybean cultivars. SC Anand Differentiating soybean responses to soybean cyst nematode races. DP Schmitt and JG Shannon Strategies for improved soybean yields and profits in the Southern US. JH Palmer Contributed papers Evaluation of resistance to Rhizoctonia Foliar Blight of soybean. CS Kousik, GB Padgett, JP Snow, and BG Harville Five years of soybean variety testing for SDS response. PT Gibson, M Schmidt, MA Shenaut, and O Myers, Jr Effect of tillage, planting date, and cultivar on the severity of sudden death syndrome, Septoria brown spot and downy mildew of soybean. JA Wrather, TL Niblack, GS Smith, and SC Anand Effect sof soybean planting date on severity of stem canker. AY Chambers Comparative virulence of stem canker isolates from southern soybean growing areas. GL Sciumbato and BL Keeling Effects of a low rate of aldicarb on soybean canopy development and yield, weed and insect populations in Heterodera glycines-infested fields. SR Koenning, KR Barker, HD Coble, and JR Bradley Effect of soybean cyst nematode on soybean isolines differing for maturity. WJ Wiebold and TL Niblack Effect of repeated application of selected herbicides and nematicides/insecticides on soybean cyst nematode density. P Donald, A Keaster, R Kremer, and B Sims Southern United States soybean disease loss estimate for 1991. Southern Soybean Disease Workers, Soybean Disease Loss Estimate Committee. Compiled by GL Sciumbato and DL Turnage SSDW Treasurer\u27s report. GG Hammes Southern Soybean Disease Workers 1990-1991 committee chairmen Southern Soybean Disease Workers 1991 award recipients Proceedings of the Southern Soybean Disease Workers is published annually by the Southern Soybean Disease Workers. Text, references, figures, and tables are reproduced as they were submitted by the author(s). The opinions expressed by the participants at this conference are their own and do not necessarily represent the views of the Southern Soybean Disease Workers. Mention of trademark or propriety product in this Proceedings does not constitute a guarantee, warranty, of endorsement of that product by the Southern Soybean Disease Workers

    Patterns of Courtship for Remarriage: Implications for Child Adjustment and Parent-Child Relationships

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    Most children who experience their parents\u27 divorce also experience their custodial parent\u27s remarriage. However, research has not addressed how patterns of courtship for remarriage influence the developing child and his or her relationships in the new family. This longitudinal study focuses on 57 remarried, stepfather families with a target child aged 9 to 13, using multimethod, multi-informant measures of child adjustment and parent-child relationships. Comparisons were made to determine whether the custodial mother\u27s number of dating partners, remarriage courtship length, or the timing and sequence of typical courtship stages affected the child\u27s adjustment and his or her relationships with the residential parents after remarriage. Results indicated that a longer time spent in a divorced, mother-custody household was associated with continuing difficulty in stepfather-stepchild relationships and lower levels of the child\u27s social competence during the initial months following remarriage. In addition, children whose custodial mother cohabited before remarriage appeared to be more socially competent throughout the two years after remarriage, while also experiencing less negative family relationships. Assertions about the ideal timing of courtship for remarriage are challenged

    Surface charges and dynamical Killing tensors for higher spin gauge fields in constant curvature spaces

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    In the context of massless higher spin gauge fields in constant curvature spaces, we compute the surface charges which generalize the electric charge for spin one, the color charges in Yang-Mills theories and the energy-momentum and angular momentum for asymptotically flat gravitational fields. We show that there is a one-to-one map from surface charges onto divergence free Killing tensors. These Killing tensors are computed by relating them to a cohomology group of the first quantized BRST model underlying the Fronsdal action.Comment: 21 pages Latex file, references and comment adde

    Evaluation of Immunogenicity and Efficacy of Fasciola hepatica Tetraspanin 2 (TSP2) Fused to E. coli Heat-Labile Enterotoxin B Subunit LTB Adjuvant Following Intranasal Vaccination of Cattle

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    Fasciolosis, caused by the liver flukes Fasciola hepatica and F. gigantica, is an economically important and globally distributed zoonotic disease. Liver fluke infections in livestock cause significant losses in production and are of particular concern to regions where drug resistance is emerging. Antigens of the F. hepatica surface tegument represent promising vaccine candidates for controlling this disease. Tetraspanins are integral tegumental antigens that have shown partial protection as vaccine candidates against other trematode species. The Escherichia coli heat-labile enterotoxin’s B subunit (LTB) is a potent mucosal adjuvant capable of inducing an immune response to fused antigens. This study investigates the potential of F. hepatica tetraspanin 2 extracellular loop 2 (rFhTSP2) as a protective vaccine antigen and determines if fusion of FhTSP2 to LTB can enhance protection in cattle. Cattle were immunised subcutaneously with rFhTSP2 mixed in the Freund’s adjuvant and intranasally with rLTB-FhTSP2 in saline, accounting for equal molar ratios of tetraspanin in both groups. Vaccination with rFhTSP2 stimulated a strong specific serum IgG response, whereas there was no significant serum IgG response following rLTB-FhTSP2 intranasal vaccination. There was no substantial antigen specific serum IgA generated in all groups across the trial. Contrastingly, after the fluke challenge, a rise in antigen specific saliva IgA was observed in both vaccination groups on Day 42, with the rLTB-FhTSP2 vaccination group showing significant mucosal IgA production at Day 84. However, neither vaccine group showed a significant reduction of fluke burden nor faecal egg output. These results suggest that intranasal vaccination with rLTB-FhTSP2 does elicit a humoral mucosal response but further work is needed to evaluate if mucosal delivery of liver fluke antigens fused to LTB is a viable vaccine strategy

    Gender, migration and the ambiguous enterprise of professionalizing domestic service: the case of vocational training for the unemployed in France

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    Drawing on ethnographic data concerning migrant male domestic workers, this article examines the gendered dimensions of the process of racialization in Italy and France. First, it shows that specific racialized constructions of masculinity are mobilized by the employers as well as by training and recruitment agencies. These constructions of masculinity are related to different forms of organization of the sector in each country and to different ideologies about the integration of migrants. Second, the data presented reveal the strategies used by migrant male domestic workers to reaffirm their masculinity in a traditionally feminized sector. In doing so, this article intends to explore the connections between international migration and the gendering of occupations, with regard to the construction and management of masculinities in domestic service. Finally, by examining men’s experiences, this article aims to contribute to a more complex definition of the international division of care work

    An analysis of fast photochemistry over high northern latitudes during spring and summer using in-situ observations from ARCTAS and TOPSE

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    Observations of chemical constituents and meteorological quantities obtained during the two Arctic phases of the airborne campaign ARCTAS (Arctic Research of the Composition of the Troposphere from Aircraft and Satellites) are analyzed using an observationally constrained steady state box model. Measurements of OH and HO2 from the Penn State ATHOS instrument are compared to model predictions. Forty percent of OH measurements below 2 km are at the limit of detection during the spring phase (ARCTAS-A). While the median observed-to-calculated ratio is near one, both the scatter of observations and the model uncertainty for OH are at the magnitude of ambient values. During the summer phase (ARCTAS-B), model predictions of OH are biased low relative to observations and demonstrate a high sensitivity to the level of uncertainty in NO observations. Predictions of HO2 using observed CH2O and H2O2 as model constraints are up to a factor of two larger than observed. A temperature-dependent terminal loss rate of HO2 to aerosol recently proposed in the literature is shown to be insufficient to reconcile these differences. A comparison of ARCTAS-A to the high latitude springtime portion of the 2000 TOPSE campaign (Tropospheric Ozone Production about the Spring Equinox) shows similar meteorological and chemical environments with the exception of peroxides; observations of H2O2 during ARCTAS-A were 2.5 to 3 times larger than those during TOPSE. The cause of this difference in peroxides remains unresolved and has important implications for the Arctic HOx budget. Unconstrained model predictions for both phases indicate photochemistry alone is unable to simultaneously sustain observed levels of CH2O and H2O2; however when the model is constrained with observed CH2O, H2O2 predictions from a range of rainout parameterizations bracket its observations. A mechanism suitable to explain observed concentrations of CH2O is uncertain. Free tropospheric observations of acetaldehyde (CH3CHO) are 2–3 times larger than its predictions, though constraint of the model to those observations is sufficient to account for less than half of the deficit in predicted CH2O. The box model calculates gross O3 formation during spring to maximize from 1–4 km at 0.8 ppbv d−1, in agreement with estimates from TOPSE, and a gross production of 2–4 ppbv d−1 in the boundary layer and upper troposphere during summer. Use of the lower observed levels of HO2 in place of model predictions decreases the gross production by 25–50%. Net O3 production is near zero throughout the ARCTAS-A troposphere, and is 1–2 ppbv in the boundary layer and upper altitudes during ARCTAS-B

    Climate Change, Tropospheric Ozone and Particulate Matter, and Health Impacts

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    We review how climate change could affect future concentrations of tropospheric ozone and particulate matter (PM), and what changing concentrations could mean for population health, as well as studies projecting the impacts of climate change on air quality and the impacts of these changes on morbidity/mortality. Climate change could affect local to regional air quality through changes in chemical reaction rates, boundary layer heights that affect vertical mixing of pollutants, and changes in synoptic airflow patterns that govern pollutant transport. Sources of uncertainty are the degree of future climate change, future emissions of air pollutants and their precursors, and how population vulnerability may change in the future. Given the uncertainties, projections suggest that climate change will increase concentrations of tropospheric ozone, at least in high-income countries when precursor emissions are held constant, increasing morbidity/mortality. There are few projections for low- and middle-income countries. The evidence is less robust for PM, because few studies have been conducted. More research is needed to better understand the possible impacts of climate change on air pollution-related health impacts
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