1,915 research outputs found

    Nanodiamond arrays on glass for quantification and fluorescence characterisation

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    Quantifying the variation in emission properties of fluorescent nanodiamonds is important for developing their wide-ranging applicability. Directed self-assembly techniques show promise for positioning nanodiamonds precisely enabling such quantification. Here we show an approach for depositing nanodiamonds in pre-determined arrays which are used to gather statistical information about fluorescent lifetimes. The arrays were created via a layer of photoresist patterned with grids of apertures using electron beam lithography and then drop-cast with nanodiamonds. Electron microscopy revealed a 90% average deposition yield across 3,376 populated array sites, with an average of 20 nanodiamonds per site. Confocal microscopy, optimised for nitrogen vacancy fluorescence collection, revealed a broad distribution of fluorescent lifetimes in agreement with literature. This method for statistically quantifying fluorescent nanoparticles provides a step towards fabrication of hybrid photonic devices for applications from quantum cryptography to sensing

    Does the World Need U.S. Farmers Even if Americans Don’t?

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    We consider the implications of trends in the number of U.S. farmers and food imports on the question of what role U.S. farmers have in an increasingly global agrifood system. Our discussion stems from the argument some scholars have made that American consumers can import their food more cheaply from other countries than it can produce it. We consider the distinction between U.S. farmers and agriculture and the effect of the U.S. food footprint on developing nations to argue there might be an important role for U.S. farmers, even if it appears Americans don’t need them. For instance, we may need to protect U.S. farmland and, by implication, U.S. farmers, for future food security needs both domestic and international. We also explore the role of U.S. farmers by considering the question of whether food is a privilege or a right. Although Americans seem to accept that food is a privilege, many scholars and commentators argue that, at least on a global scale, food is a right, particularly for the world’s poor and hungry. If this is the case, then U.S. farmers might have a role in meeting the associated obligation to ensure that the poor of the world have enough food to eat. We look at the consequences of determining that food is a right versus a privilege and the implications of that decision for agricultural subsidies as well as U.S. agriculture and nutrition policies.Food Security and Poverty,

    Control of contagious bovine pleuropneumonia: knowledge, attitudes, perceptions and practices in Narok district of Kenya

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    CBPP is an important transboundary disease in sub-Saharan Africa whose control is urgent. Participatory data collection involving 52 focus group discussions in 37 village clusters and key informant interviews, a cross-sectional study involving 232 households and a post-vaccination follow up involving 203 households was carried out in 2006–2007 in Narok South district of Kenya. This was to investigate knowledge, attitudes, perceptions and practices (KAPP) associated with control of CBPP as well as the adverse post-vaccination reactions in animals in order to advice the control policy. The community perceived trans-boundary CBPP threat to their cattle. They had traditional disease coping mechanisms and were conversant with CBPP prevention and control with 49.8% (95%CI: 42.8–56.7%) giving priority to CBPP control. However, 12.9% (95%CI: 9.0–18.1%) of pastoralists had no knowledge of any prevention method and 10.0% (95%CI: 6.5–14.7%) would not know what to do or would do nothing in the event of an outbreak. Although 43.5% (95%CI: 37.1–50.2%) of pastoralists were treating CBPP cases with antimicrobials, 62.5% (95%CI: 52.1–71.7%) of them doubted the effectiveness of the treatments. Pastoralists perceived vaccination to be the solution to CBPP but vaccination was irregular due to unavailability of the vaccine. Vaccination was mainly to control outbreaks rather than preventive and exhibited adverse post-vaccination reactions among 70.4% (95%CI: 63.6–76.5%) of herds and 3.8% (95%CI: 3.5–4.2%) of animals. Consequently, nearly 25.2% (95%CI: 18.5–33.2%) of pastoralists may resist subsequent vaccinations against CBPP. Pastoralists preferred CBPP vaccination at certain times of the year and that it is combined with other vaccinations. In conclusion, pastoralists were not fully aware of the preventive measures and interventions and post-vaccination reactions may discourage subsequent CBPP vaccinations. Consequently there is need for monitoring and management of post vaccination reactions and awareness creation on CBPP prevention and interventions and their merits and demerits. CBPP vaccine was largely unavailable to the pastoralists and the preference of the pastoralists was for vaccination at specified times and vaccine combinations which makes it necessary to avail the vaccine in conformity with the pastoralists preferences. In addition, planning vaccinations should involve pastoralists and neighbouring countries. As the results cannot be generalized, further studies on CBPP control methods and their effectiveness are recommended

    Scaling relations and critical exponents for two dimensional two parameter maps

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    In this paper we calculate the critical scaling exponents describing the variation of both the positive Lyapunov exponent, λ+, and the mean residence time, τ , near the second order phase transition critical point for dynamical systems experiencing crisis-induced intermittency. We study in detail 2-dimensional 2-parameter nonlinear quadratic mappings of the form: Xn+1 = f1(Xn, Yn; A,B) and Yn+1 = f2(Xn, Yn; A,B) which contain in their parameter space (A,B) a region where there is crisis induced intermittent behaviour. Specifically, the Henon, the Mira 1, and Mira 2 maps are investigated in the vicinity of the crises.We show that near a critical point the following scaling relations hold: τ ∌ |A−Ac|−γ, (λ+ −λ+c ) ∌| A−Ac |ÎČA and (λ+ −λ+c ) ∌| B −Bc |ÎČB. The subscript c on a quantity denotes its value at the critical point. All these maps exhibit a chaos to chaos second order phase transition across the critical point. We find these scaling exponents satisfy the scaling relation Îł = ÎČB( 1 ÎČA − 1), which is analogous to Widom’s scaling law. We find strong agreement between the scaling relationship and numerical results

    Police accountability and the Irish law of evidence

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    "Common law courts have differed on whether and to what extent an exclusionary rule should be used as a tool to impose standards on the police. The Irish courts have pursued an uncompromising approach in this area. Basing themselves on the imperative of upholding the constitutional rights of the accused, they have been willing to exclude relevant and cogent evidence on the basis that it was obtained by the police in breach of those rights. This article locates the Irish constitutional exclusionary rule in the broader context of the role of the law of evidence in police governance. Citing specific examples from the Irish legislation and case law, it shows how recent legislative interventions and some judicial hesitancy have fuelled inconsistent and contradictory trends. It concludes that there is now a pressing need for reflection on the respective roles of the legislature and the courts in this area." [author's abstract

    Sex Differences in the Hemodynamic Response to Arm Elevation

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    Please view abstract in the attached PDF file

    Vascular Changes Following Exercise-Induced Hyperthermia

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    Please view abstract in the attached PDF file

    Does the World Need U.S. Farmers Even if Americans Don't?

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    We consider the implications of trends in the number of U.S. farmers and food imports on the question of what role U.S. farmers have in an increasingly global agrifood system. Our discussion stems from the argument some scholars have made that American consumers can import their food more cheaply from other countries than it can produce it. We consider the distinction between U.S. farmers and agriculture and the effect of the U.S. food footprint on developing nations to argue there might be an important role for U.S. farmers, even if it appears Americans don't need them. For instance, we may need to protect U.S. farmland and, by implication, U.S. farmers, for future food security needs both domestic and international. We also explore the role of U.S. farmers by considering the question of whether food is a privilege or a right. Although Americans seem to accept that food is a privilege, many scholars and commentators argue that, at least on a global scale, food is a right, particularly for the world's poor and hungry. If this is the case, then U.S. farmers might have a role in meeting the associated obligation to ensure that the poor of the world have enough food to eat. We look at the consequences of determining that food is a right versus a privilege and the implications of that decision for agricultural subsidies as well as U.S. agriculture and nutrition policies

    Analysis of social, fiscal, and structural factors affecting integrated pest management programs in Missouri and implications for future programs to protect water quality

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    Integrated Pest Management (IPM) has experienced a resurgence of interest due in part to continuing reports of drinking water contamination by agricultural pesticides. In response to the decertification of certain pesticides used for soil insect control on corn, in the early 1970s federal programs established Cooperative Extension Service sponsored IPM programs in several midwestern States to promote insect scouting on corn and cotton. This report documents the various factors which facilitated the growth and decline of these programs in Missouri and the ongoing transformation of such services into the private sector and other agencies. The objective of this report is to provide policy prescriptions to enhance the future adoption of IPM in Missouri and other areas that will facilitate the protection of water resources. Research in Missouri regarding pesticide use practices and water quality issues indicates that there is a considerably higher incidence of IPM use in counties that historically had, or still currently have, Extension sponsored programs. Interviews were conducted with University personnel responsible for implementing these programs, county Extension agents responsible for overseeing the programs, private sector businesspeople who are currently offering IPM services, and farm opeators who previously used, and/or now participate in, IPM Extension programs or private services. Interviewees were asked what factors contributed to the success, failure, and/or transformation of the county programs. Results indicate that these factors include quality and turnover of the scouts, committment of the Extension agent, economic and climatological variables, institutional support, and packaging IPM programs with other programs such as irrigation.Project # G-2029-04 Agreement # 14-08-0001-G-2029-0
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