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81.
82.
Andrea Y. Garzón-Serrano M.Sc. César A. Sierra Ph.D. Oscar Rodríguez-Bejarano Dr.Sc. Diana Sinuco Dr.Sc. 《Journal of forensic sciences》2020,65(4):1085-1093
Ammonium nitrate fuel oil is an explosive mixture found in most antipersonnel landmines (APL) buried throughout the Colombian territory. During more than 50 years of internal conflict, the Colombian government has found that trained dogs are the most effective method to detect APL. However, the olfactive signature in ANFO is unknown and also if there are differences in detection related to the explosive manufacturing origin. Therefore, this work begins with the analytical validation of the method used to determine ammonia, in its derivatized form as carbamate, released by home-made ANFO using HS-SPME-GC-FID. Once validated, the method was used to identify ammonia and other organic volatile compounds present in ANFO, under laboratory and simulated field conditions. The validation process includes the evaluation of the optimum conditions for the derivation and extraction of butylcarbamate, the determination of the working ranges with linear response in FID, the limits of detection and quantification, the sensitivity, and the precision. The results of the validation established linearity and sensitivity in a concentration between 20 and 120 mg/L, as well as low limits of detection and quantification of 6.4 and 21.4 mg/L, respectively. Also, an intermediate precision of 11% for butylcarbamate with a repeatability of 8%. The validated method showed in real samples of home-made ANFO besides ammonia, the presence of low molecular methylamines, and also exhibited differences in volatile compositions according to the origin. The objective of this work is to offer a reliable analytical methodology for the extraction and analysis of volatile compounds from ANFO. 相似文献
83.
Monica K. Kansiime Justus Ochieng Radegunda Kessy Daniel Karanja Dannie Romney Victor Afari-Sefa 《Development in Practice》2018,28(4):480-493
African indigenous vegetables (AIVs) have potential to sustainably address malnutrition, a growing problem in sub-Saharan Africa. Their consumption is however, limited by poor perceptions and lack of awareness of nutritional benefits. There is limited evidence of the effectiveness of community-focused information dissemination approaches in influencing participants’ perceptions and uptake of innovations in AIVs to address malnutrition. This article aims to fill this knowledge gap, using a case study focusing on pastoral communities in Monduli district in northern Tanzania. Target communities participated in a community-based nutritional outreach facilitated by the Good Seed Initiative (GSI), held at Monduli district hospital in September 2014. The results provide evidence of the achievements of the GSI intervention, and the effectiveness of alternative information dissemination approaches. 相似文献
84.
What Levels of Racial Diversity Can Be Achieved with Socioeconomic‐Based Affirmative Action? Evidence from a Simulation Model
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Sean F. Reardon Rachel Baker Matt Kasman Daniel Klasik Joseph B. Townsend 《Journal of policy analysis and management》2018,37(3):630-657
This paper investigates to what extent socioeconomic status (SES)‐based affirmative action in college admissions can produce racial diversity. Using simulation models, we investigate the racial and socioeconomic distribution of students among colleges under the use of race‐ or SES‐based affirmative action policies, or targeted, race‐based recruitment policies. We find, first, that neither SES‐based affirmative action nor race‐targeted recruiting on their own produce levels of racial diversity achieved by race‐based affirmative action. However, the two policies in combination, although likely expensive, may yield racial diversity comparable to race‐based affirmative action. Second, the use of affirmative action policies by some colleges reduces the diversity of similar‐quality colleges without such policies. Third, the combination of SES‐based affirmative action and race recruiting results in fewer academically‐overmatched Black and Hispanic students than under race‐based affirmative action, but the schools that use both also see a reduction in the academic achievement of enrolled students. 相似文献
85.
While the fertility effects of improving teenagers’ access to contraception are theoretically ambiguous, most empirical work has shown that access decreases teen fertility. In this paper, we consider the fertility effects of access to condoms—a method of contraception not considered in prior work. We exploit variation across counties and across time in teenagers’ exposure to condom distribution programs in schools. We find that access to condoms in schools increases teen fertility by about 12 percent. The results suggest that the effects of condom access varied significantly across different programs; the positive fertility estimates are driven by communities where condoms are provided without mandated counseling. Programs that mandated counseling have zero or negative fertility effects, but estimates on these counties are less robust across specifications. 相似文献
86.
AbstractScalability can be understood as the ability to expand without changing. Yet, expanding an intervention to a global scale, we suggest, is a significant and difficult accomplishment. In this paper we propose to explore the kind of evidential exigencies that this accomplishment involves. To do so, we focus on the field of global health and examine how child immunization against the pneumococcus bacterium has been scaled up in low-income countries. The paper first attends to initial epidemiological scrutiny that revealed the existence of a large-scale public health problem and the possibility of an expandable solution (vaccination). It then describes the set-up of a funding arrangement using overseas aid to purchase vaccine doses manufactured by pharmaceutical companies, before paying attention to various frictions that affect the widespread use of pneumococcal vaccines. In these different moments through which scalability is accomplished, always partially and temporarily, we show that a dual activity can be witnessed, a pivoting between referential work and forward projection. To conclude, we suggest that scalability is more usefully approached as a form of expansion that is always attentive to the possibilities of change. 相似文献
87.
This paper deals with the long-term evolution of dock labor in Dakar. Through the utilization of archival sources and their analysis, this investigation explores the changes that occurred in this sector and primarily the reform plan developed during the world wars but that was never introduced into the labor regulations, mainly due to the colonial regime. In addition, this paper studies the legal changes since the 1970s when the dockers’ statute was settled. Furthermore, this research uses oral testimony from retired Senegalese dockers to study the way these workers observed these structural changes. It is the first time that this topic has been explored for the port of Dakar from a historical long-term perspective. 相似文献
88.
89.
Ramón Máiz 《Nationalism and Ethnic Politics》2018,24(2):181-200
This article asks why, in contrast to other historic territories with a regional language, such as Catalonia and the Basque Country, nationalist parties in the Autonomous Community of Galicia receive less electoral support. Going beyond prior explanations of this counterintuitive political outcome, which were mainly based on economic, sociological, and institutional factors, this piece of research sheds light on the strategies of political parties. It examines not only nationalist forces but statewide ones that successfully compete in Galicia. Our analysis is focused on the Bloque Nacionalista Galego (BNG) because this is the only nationalist force that has consistently achieved representation within the regional Parliament. Along with BNG's translation into party positions in both the left-right and center-periphery dimensions, the article's main contribution is its updating of the BNG's three framing strategies: the nationalism/“Spanishism” (1982–1993), the “common project” discourse (1993–2005), and the sovereigntist one (2005 onward). Shifts in public opinion regarding the territorial model and other attitudes toward self-government are also examined. 相似文献
90.
Daniel M. Butler Craig Volden Adam M. Dynes Boris Shor 《American journal of political science》2017,61(1):37-49
We introduce experimental research design to the study of policy diffusion in order to better understand how political ideology affects policymakers’ willingness to learn from one another's experiences. Our two experiments–embedded in national surveys of U.S. municipal officials–expose local policymakers to vignettes describing the zoning and home foreclosure policies of other cities, offering opportunities to learn more. We find that: (1) policymakers who are ideologically predisposed against the described policy are relatively unwilling to learn from others, but (2) such ideological biases can be overcome with an emphasis on the policy's success or on its adoption by co‐partisans in other communities. We also find a similar partisan‐based bias among traditional ideological supporters, who are less willing to learn from those in the opposing party. The experimental approach offered here provides numerous new opportunities for scholars of policy diffusion. 相似文献