4,284 research outputs found
Leibniz algebroid associated with a Nambu-Poisson structure
The notion of Leibniz algebroid is introduced, and it is shown that each
Nambu-Poisson manifold has associated a canonical Leibniz algebroid. This fact
permits to define the modular class of a Nambu-Poisson manifold as an
appropiate cohomology class, extending the well-known modular class of Poisson
manifolds
Developing a Feasible Survey for Community Organizations to Evaluate a Healthy Relationships Program
For community-based organizations that work with vulnerable youth, evaluation measures and activities are important strategies for assessing a program’s impact on youth on different outcomes. However, rigorous program evaluation involving pretest-posttest measures and control trials are impractical to implement in community settings. It is critical for organizations to continuously measure programming efficacy, as it is an issue of accountability, ethical responsibility, and program improvement. Additionally, funders, policymakers, and stakeholders typically require organizations to monitor the effects of programming in their setting to continue receiving support. However, organizations conduct program evaluation under many constraints. There is an emergent need for a feasible tool for community organizations to collect data from their programs in an efficient yet effective manner that captures impactful information about program efficacy. The present study follows the development of a retrospective survey for community organizations to evaluate the Healthy Relationships Plus – Enhanced (HRP-E) program. The purpose of such a survey is to provide a measure for organizations to use so they can engage in ongoing program evaluation when more rigorous approaches are not feasible. An initial pool of items was generated based on HRP-E content and previous Fourth R surveys. Upon the development of the survey, nine experts were interviewed to gain their feedback on the draft. Interview transcripts from experts were coded and used for an inductive thematic analysis to organize, find patterns, and extract meaning from the interviews. Results discuss the major themes from the interviews and provide insight on important considerations for survey development in the context of research with community organizations and youth
Oxidation of the borohydride Ion at silver nanoparticles on a glassy carbon electrode (GCE) using pulsed potential techniques
Direct oxidation borohydride fuel cells are very attractive energy conversion devices. Silver has been reported as one of the few materials which can catalyze an 8-electron oxidation. Potential step amperometric pulse techniques to synthesize nanostructured silver material on flat glassy carbon electrodes is reported and significant differences with bulk silver deposit have been observed. The oxidation of borohydride ion on the silver particles occurs at -0.025 V vs. SCE and the potential decreases towards negative values at longer cycle times. The oxidation current also decreases with the number of cycles, suggesting that the silver active sites become partially blocked by oxidation products of borohydride. The electroactive area per unit electrode area of silver was relatively low for particles deposited using potential step amperometric techniques on glassy carbon (0.002 cm2 per cm-2) compared with the area found at a polycrystalline silver electrode (0.103 cm2 per cm-2
Brazil: economic study of cassava
A series of studies were carried out in Brazil, on a regional basis, to determine how cassava can fit into the Brazilian agricultural economy in the future so as to assist the country in reaching policy goals (improved welfare of the rural community and increased availability of low-priced food). The recent developments in the Brazilian agricultural sector are summarized with emphasis on agricultural policies and on the balance between food production and exports. Urbanization as well as wheat subsidies have reduced the importance of cassava. Current policies, however, are found to favor food crops such as cassava that are produced by the small farmers. Trends in cassava for human food and its future potential role are also analyzed. The role of farinha as a staple food should be improved; increased per capita consumption will depend on better availability, better quality, and lower prices. To increase the consumption of fresh cassava, it is necessary to reduce marketing margins. The reduction of production costs of cassava starch is also crucial. The rapidly expanding feed industry is discussed with reference to cassava supply. Improved production technology would mean increased benefits to both producers and consumers. A dried cassava industry would reduce the need to import maize, stabilize on-farm prices of cassava, and extend the market size of the crop, particularly in NE Brazil. The cost structure of cassava production and processing is analyzed from the viewpoint of the cassava's future role as a source of rural income and its contribution to the food and feed supply. (CIAT)Se realizo una serie de estudios en Brasil, a nivel regional, para determinar el papel de la yuca en la economia agricola brasilera del futuro y ayudar a alcanzar las metas propuestas en las diferentes politicas (mayor bienestar de la comunidad rural y mayor disponibilidad de alimentos a bajo costo). Se resumen los ultimos avances en el sector agricola brasilero, con enfasis en las politicas agricolas y en el balance entre produccion de alimentos y exportaciones. La urbanizacion y los subsidios al trigo le han restado importancia a la yuca. Las politicas actuales, sin embargo, favorecen los cultivos alimenticios, como la yuca, producidos por pequenos agricultores. Tambien se analizan las tendencias del uso de la yuca en la alimentacion humana y su potencial futuro. Se debe mejorar el papel de la farinha como alimento basico; el aumento en el consumo per capita dependera de una mayor disponibilidad, una mejor calidad y precios mas bajos. Para aumentar el consumo de raices frescas es necesario reducir los margenes de mercadeo. Tambien es importante la reduccion de los costos de produccion del almidon de yuca. Se discute la creciente industria de alimentos para animales con referencia a la oferta de yuca. Un tecnologia de produccion mejorada significaria mayor beneficio tanto para los productores como para los consumidores. Una industria de yuca seca reduciria la necesidad de importar maiz, estabilizaria los precios de la yuca a nivel de finca y ampliaria el mercado del cultivo, particularmente en el nordeste del Brasil. Se analiza la estructura de los costos de produccion y procesamiento de la yuca desde el punto de vista de su futuro papel como fuente de ingresos a nivel rural y su contribucion a la oferta de alimentos para humanos y animales. (CIAT
Toll-managed lane pioneers: Lessons from five US states
Toll-managed lanes have become an increasingly popular technique among transportation policymakers for managing congestion on existing highways and, in some cases, financing the construction of new lanes in congested urban corridors. Although growing in popularity, the adoption of these facilities is concentrated in five states: Texas, California, Colorado, Minnesota, and Florida. This paper examines the adoption and utilization of toll-managed lanes in these pioneer states. Using archival, case-based research, our analysis suggests that the adoption of toll-managed lanes was driven by a combination of factors, including rapid population growth, near or above average growth in vehicle miles traveled (VMT), and insufficient gas tax funding for transportation investments. Implementation was also generally similar across states but some of the pioneers delegated the management of their toll-managed lane programs to special regional highway authorities while others used state highway agencies
Superheavy Dark Matter with Discrete Gauge Symmetries
We show that there are discrete gauge symmetries protect naturally heavy X
particles from decaying into the ordinary light particles in the supersymmetric
standard model. This makes the proposal very attractive that the superheavy X
particles constitute a part of the dark matter in the present universe. It is
more interesting that there are a class of discrete gauge symmetries which
naturally accommodate a long-lived unstable X particle. We find that in some
discrete Z_{10} models, for example, a superheavy X particle has lifetime
\tau_X \simeq 10^{11}-10^{26} years for its mass M_X \simeq 10^{13}-10^{14}
GeV. This long lifetime is guaranteed by the absence of lower dimensional
operators (of light particles) couple to the X. We briefly discuss a possible
explanation for the recently observed ultra-high-energy cosmic ray events by
the decay of this unstable X particle.Comment: 9 pages, Late
Some results on cubic and quartic quasi-interpolation of optimal approximation order on type-1 triangulations
The Receptor-Like Kinase SERK3/BAK1 Is Required for Basal Resistance against the Late Blight Pathogen Phytophthora infestans in Nicotiana benthamiana
BACKGROUND The filamentous oomycete plant pathogen Phytophthora infestans causes late blight, an economically important disease, on members of the nightshade family (Solanaceae), such as the crop plants potato and tomato. The related plant Nicotiana benthamiana is a model system to study plant-pathogen interactions, and the susceptibility of N. benthamiana to Phytophthora species varies from susceptible to resistant. Little is known about the extent to which plant basal immunity, mediated by membrane receptors that recognise conserved pathogen-associated molecular patterns (PAMPs), contributes to P. infestans resistance. PRINCIPAL FINDINGS We found that different species of Phytophthora have varying degrees of virulence on N. benthamiana ranging from avirulence (incompatible interaction) to moderate virulence through to full aggressiveness. The leucine-rich repeat receptor-like kinase (LRR-RLK) BAK1/SERK3 is a major modulator of PAMP-triggered immunity (PTI) in Arabidopsis thaliana and N. benthamiana. We cloned two NbSerk3 homologs, NbSerk3A and NbSerk3B, from N. benthamiana based on sequence similarity to the A. thaliana gene. N. benthamiana plants silenced for NbSerk3 showed markedly enhanced susceptibility to P. infestans infection but were not altered in resistance to Phytophthora mirabilis, a sister species of P. infestans that specializes on a different host plant. Furthermore, silencing of NbSerk3 reduced the cell death response triggered by the INF1, a secreted P. infestans protein with features of PAMPs. CONCLUSIONS/SIGNIFICANCE We demonstrated that N. benthamiana NbSERK3 significantly contributes to resistance to P. infestans and regulates the immune responses triggered by the P. infestans PAMP protein INF1. In the future, the identification of novel surface receptors that associate with NbSERK3A and/or NbSERK3B should lead to the identification of new receptors that mediate recognition of oomycete PAMPs, such as INF1.This work was supported by the Gatsby Charitable Foundation, BBSRC, Nuffield Foundation and the German Research Foundation (DFG). SS was supported by a personal research fellowship (SCHO1347/1-1). JPR is an Australian Research Council Future Fellow (FT0992129). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript
Unifying CP violations of quark and lepton sectors
A preliminary determination of the Dirac phase in the PMNS matrix is
\dell\approx -\frac{\pi}{2}. A rather accurately determined Jarlskog
invariant in the CKM matrix is close to the maximum. Since the phases in
the CKM and PMNS matrices will be accurately determined in the future, it is an
interesting problem to relate these two phases. This can be achieved in a
families-unified grand unification if the weak CP violation is introduced
spontaneously {\it \`a la} Froggatt and Nielsen at a high energy scale, where
only one meaningful Dirac CP phase appears.Comment: 10 pages with 3 figure
- …