520 research outputs found

    Where the Line Draws Blood: Faulkner, Ward, and the Policing of Race

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    Like William Faulkner, Jesmyn Ward has created a richly textured, fictional-yet-historically-true Mississippi community in her novels. Yet their perspectives on race are radically different. One sees race as an immutable fact in the mind of white people. The other sees race as something created by a centuries-old history of policing African-American movement—a history that begins in slavery, and continues with deadly effect to this day

    The Unconquerable Archive

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    Paper on "the relationship between the sources of the Southern Historical Collection and the historiography of the antebellum South," and how the same documents were used at different times and in different ways to write the history of slavery. Presented at Southern Sources: A Symposium Celebrating Seventy-Five Years of the Southern Historical Collection, 18-19 March 2005 in the Wilson Library at the University of North Carolina at Chapel Hill

    Freedom on the Move: A Crowdsourced, Comprehensive Database of North American Runaway Slave Advertisements

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    'Freedom on the Move' (FOTM) creates a digital resource from an estimated 100,000 runaway slave advertisements from pre-1865 U.S. newspapers. Placed by enslavers when enslaved people attempted to escape, these ads included extensive information about fugitives. They comprise the richest source of information about enslaved individuals in the United States, yet no comprehensive collection of them exists. FOTM will collect these ads and use crowdsourcing to parse their data into a database, enabling sophisticated new analyses of the history of U.S. slavery. A crowdsourcing interface will provide a site for public engagement with an enduring national trauma, supporting lessons for K-12, university, and museum education. The database will be freely available for browsing and exportable for research. NEH start-up funding will enable us to build tools for incorporating large-scale data from contributors, creating a prototype for future expansions of this and similar digital resources

    Bird radar validation in the field by time-referencing line-transect surveys

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    Track-while-scan bird radars are widely used in ornithological studies, but often the precise detection capabilities of these systems are unknown. Quantification of radar performance is essential to avoid observational biases, which requires practical methods for validating a radar’s detection capability in specific field settings. In this study a method to quantify the detection capability of a bird radar is presented, as well a demonstration of this method in a case study. By time-referencing line-transect surveys, visually identified birds were automatically linked to individual tracks using their transect crossing time. Detection probabilities were determined as the fraction of the total set of visual observations that could be linked to radar tracks. To avoid ambiguities in assigning radar tracks to visual observations, the observer’s accuracy in determining a bird’s transect crossing time was taken into account. The accuracy was determined by examining the effect of a time lag applied to the visual observations on the number of matches found with radar tracks. Effects of flight altitude, distance, surface substrate and species size on the detection probability by the radar were quantified in a marine intertidal study area. Detection probability varied strongly with all these factors, as well as species-specific flight behaviour. The effective detection range for single birds flying at low altitude for an X-band marine radar based system was estimated at ∼1.5 km. Within this range the fraction of individual flying birds that were detected by the radar was 0.50±0.06 with a detection bias towards higher flight altitudes, larger birds and high tide situations. Besides radar validation, which we consider essential when quantification of bird numbers is important, our method of linking radar tracks to ground-truthed field observations can facilitate species-specific studies using surveillance radars. The methodology may prove equally useful for optimising tracking algorithms

    Soil carbon dynamic associated to land-use changes in semi-arid forests of Argentina

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    Fil: Conti, G. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Conti, G. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Diversidad Biológica y Ecología; Argentina.Fil: Kowaljow, E. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Kowaljow, E. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Diversidad Biológica y Ecología; Argentina.Fil: Baptist, F. Biotope; Francia.Fil: Rumpel, C. Centre national de la recherche scientifique; Francia.Fil: Cuchietti, A. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Cuchietti, A. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Diversidad Biológica y Ecología; Argentina.Fil: Díaz, S. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Díaz, S. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Diversidad Biológica y Ecología; Argentina.Land-use change represents one of the main drivers of global climatic change, affecting the amount and quality of organic matter (OM) in soils worldwide. A reduction in the amount of biomass due to forest management is expected to affect both the amount of new OM going into the soil and its microbial decomposability due to changes in soil environmental conditions. These changes should impact soil microbial communities, their activity and decomposition rates, affecting the amount and quality of organic carbon (OC) remaining in the soil. In order to obtain information on the effect of land-use change on the OM quantity and quality, its origin and its degree of stabilization (i.e., microbial decomposability), we characterized the amount of OC, the lignin and polysaccharide compounds by wet chemical analysis, as well as basal respiration rates across a disturbance gradient (n=20) in a semiarid Chaco forest of central Argentina. Disturbance reduced the amount and quality of litterfall, reflected in a reduction in SOM content. Soil carbohydrates content followed the same trend but lignin was not affected by land-use change. Although basal CO2 effluxes showed the same pattern than SOM content, when normalized per OC content, they showed the opposite trend, with higher CO2 released per C in sites with lower OC and carbohydrates content. Our results support the idea that in the semi-arid Chaco forest, chemically labile compounds are more vulnerable to disturbance, but also that OM could be protected and stabilized regardless of its chemical identity.Fil: Conti, G. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Conti, G. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Diversidad Biológica y Ecología; Argentina.Fil: Kowaljow, E. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Kowaljow, E. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Diversidad Biológica y Ecología; Argentina.Fil: Baptist, F. Biotope; Francia.Fil: Rumpel, C. Centre national de la recherche scientifique; Francia.Fil: Cuchietti, A. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Cuchietti, A. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Diversidad Biológica y Ecología; Argentina.Fil: Díaz, S. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Díaz, S. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Diversidad Biológica y Ecología; Argentina.Ecologí

    Working with Nature in Wadden Sea Ports

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    Wadden Sea ports are situated at the border of the UNESCO World Heritage site Wadden Sea. Because of the protected status of this area, developing new economic activities is not straightforward. However, maintaining and developing port activities is needed to safeguard the economic viability of the Wadden Seasocio-economic region. In this paper we illustrate that sustainable port development is feasible when adopting a Working with Nature approach. This approach facilitates a design in which the proactive utilization and/or provision of ecosystem services serves as part of the engineering solution. We introduce four Working with Nature concepts that can be used in port designs, i.e. 1) optimising dredging strategies, 2) enhancing saltmarsh development, 3) creating estuarine gradients, and 4) optimising flow patterns. Based on theseconcepts, three case studies have been identified and pilot projects initiated. In the Port of Harlingen a pilot project has started in which an optimized dredging strategy is combined with saltmarsh development. Around the Port of Delfzijl an estuarine gradient is combined with the construction of a salt marsh and dredgedsediment is used for dike strengthening. For the Port of Den Helder, a new design is proposed in which the concepts of enhancing salt marsh development, creating estuarine gradients and optimizing flow patterns are combined. Our conclusion is that even in a World Heritage site such as the Wadden Sea, portdevelopment is possible when ecosystem services are used and provided for, and when a Working with Nature concept is put at the heart of the design

    Balancing food and density-dependence in the spatial distribution of an interference-prone forager

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    Foraging distributions are thought to be density-dependent, because animals not only select for a high availability and quality of resources, but also avoid conspecific interference. Since these processes are confounded, their relative importance in shaping foraging distributions remains poorly understood. Here we aimed to rank the contribution of density-dependent and density-independent effects on the spatio-temporal foraging patterns of eurasian oystercatchers. In our intertidal study area, tides caused continuous variation in oystercatcher density, providing an opportunity to disentangle conspecific interference and density-independent interactions with the food landscape. Spatial distributions were quantified using high-resolution individual tracking of foraging activity and location. In a model environment that included a realistic reconstruction of both the tides and the benthic food, we tested a family of behaviour-based optimality models against these tracking data. Density-independent interactions affected spatial distributions much more strongly than conspecific interference, even in an interference-prone species like oystercatchers. Spatial distributions were governed by avoidance of bill injury costs, selection for high interference-free intake rates and a decreasing availability of benthic bivalve prey after their exposure. These density-independent interactions outweighed interference competition in terms of effect size. We suggest that the bottleneck in our mechanistic understanding of foraging distributions may be primarily the role of density-independent prey attributes unrelated to intake rates, like damage costs in the case of oystercatchers foraging on perilous prey. At a landscape scale, above the finest inter-individual distances, effects of conspecific interaction on spatial distributions may have been overemphasised

    Prevalence of the Use of Herbal Medicines among Patients with Cancer: A Systematic Review and Meta-Analysis

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    Background: Although herbal medicines are used by patients with cancer in multiple oncology care settings, the magnitude of herbal medicine use in this context remains unclear. )e purpose of this review was to establish the prevalence of herbal medicine use among patients with cancer, across various geographical settings and patient characteristics (age and gender categories). Methods: Electronic databases that were searched for data published, from January 2000 to January 2020, were Medline (PubMed), Google Scholar, Embase, and African Index Medicus. Eligible studies reporting prevalence estimates of herbal medicine use amongst cancer patients were pooled using random-effects meta-analyses. Studies were grouped by World Bank region and income groups. Subgroup and meta regression analyses were performed to explore source of heterogeneity. Results: In total, 155 studies with data for 809,065 participants (53.95% female) met the inclusion criteria. Overall, the pooled prevalence of the use of herbal medicine among patients with cancer was 22% (95% confidence interval (CI): 18%–25%), with the highest prevalence estimates for Africa (40%, 95% CI: 23%–58%) and Asia (28%, 95% CI: 21%–35%). )e pooled prevalence estimate was higher across low- and middle-income countries (32%, 95% CI: 23%–42%) and lower across high-income countries (17%, 95% CI: 14%–21%). Higher pooled prevalence estimates were found for adult patients with cancer (22%, 95% CI: 19%–26%) compared with children with cancer (18%, 95% CI: 11%–27%) and for female patients (27%, 95% CI: 19%–35%) compared with males (17%, 95% CI: 1%–47%). Conclusion: Herbal medicine is used by a large percentage of patients with cancer use. The findings of this review highlight the need for herbal medicine to be integrated in cancer care

    The Short-term Car Flow Planning Model in Rail Freight Company – Case Study

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    AbstractWith the promotion of the environmentally friendly transportation modes (the European Commission supports the freight transport operations in the rail sector), an increase in the diversification of the demand is observed. While most rail freight companies tend to apply fixed schedules, this approach is not effective turns out to be ineffective due to the need to meet the customer's specific requirements.The purpose of this paper is to present a case study of empty wagon flow planning over a medium term horizon and to discuss the opportunities of improvement of this plans by discrete optimization. In order to increase the utilization and availability of wagons, the planning procedure with a rolling horizon has to be implemented. Unfortunately, since the plan has to be updated ca. every 4hours, this planning approach needs effective optimization tools. Our hybrid two-stage approach is designed to be implemented in such business environment. This formulation allows us to solve real life instances even for a 7-day time horizon
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