1,957 research outputs found
Duality through the symplectic embedding formalism
In this work we show that we can obtain dual equivalent actions following the
symplectic formalism with the introduction of extra variables which enlarge the
phase space. We show that the results are equal as the one obtained with the
recently developed gauging iterative Noether dualization method (NDM). We
believe that, with the arbitrariness property of the zero mode, the symplectic
embedding method (SEM) is more profound since it can reveal a whole family of
dual equivalent actions. We illustrate the method demonstrating that the
gauge-invariance of the electromagnetic Maxwell Lagrangian broken by the
introduction of an explicit mass term and a topological term can be restored to
obtain the dual equivalent and gauge-invariant version of the theory.Comment: RevTeX4, 10 pages. To appear in Int. J. Mod. Phys.
Transport of desert dust mixed with North African industrial pollutants in the subtropical Saharan Air Layer
An analysis of chemical composition data of particulate matter samples (TSP, PM<sub>10</sub> and PM<sub>2.5</sub>) collected from 2002 to 2008 in the North Atlantic free troposphere at the Izaña Global Atmospheric Watch (GAW) observatory (Tenerife, Canary Islands) shows that desert dust is very frequently mixed with particulate pollutants in the Saharan Air Layer (SAL). The study of this data set with Median Concentrations At Receptor (MCAR) plots allowed the identification of the potential source regions of the dust and particulate pollutants. Areas located at the south of the southern slope of the Atlas mountains emerge as the most frequent source of the soil desert dust advected to the northern edge of the SAL in summer. Industrial emissions occurring in Northern Algeria, Eastern Algeria, Tunisia and the Atlantic coast of Morocco appear as the most important source of the nitrate, ammonium and a fraction of sulphate (at least 60 % of the sulphate <10 μm transported from some regions) observed in the SAL. These emissions are mostly linked to crude oil refineries, phosphate-based fertilizer industry and power plants. Although desert dust emissions appear as the most frequent source of the phosphorous observed in the SAL, high P concentrations are observed when the SAL is affected by emissions from open mines of phosphate and phosphate based fertilizer industry. The results also show that a significant fraction of the sulphate (up to 90 % of sulphate <10 μm transported from some regions) observed in the SAL may be influenced by soil emissions of evaporite minerals in well defined regions where dry saline lakes (chotts) are present. These interpretations of the MCAR plots are consistent with the results obtained with the Positive Matrix Factorization (PMF2) receptor modelling. The results of this study show that North African industrial pollutants may be mixed with desert dust and exported to the North Atlantic in the Saharan Air Layer
Parental cultural models and resources for understanding mathematical achievement in culturally diverse school settings
This paper proposes that the theoretical concept of cultural models can offer useful insights into parental involvement in their child’s mathematical achievement and the resources they use to go about gaining information in culturally diverse learning settings. This examination takes place within a cultural-developmental framework and draws on the notion of cultural models to explicate parental understandings of their child’s mathematics achievement and what resources are used to make sense of this. Three parental resources are scrutinized: (a) the teacher, (b) examination test results, and (c) constructions of child development. The interviews with 22 parents revealed some ambiguity around the interpretation of these resources by the parent, which was often the result of incongruent cultural models held between the home and the school. The resources mentioned are often perceived as being unambiguous but show themselves instead to be highly interpretive because of the diversity of cultural models in existence in culturally diverse settings. Parents who are in minority or marginalized positions tend to have difficulties in interpreting cultural models held by school, thereby disempowering them to be parentally involved in the way the school would like
One-sided Cauchy-Stieltjes Kernel Families
This paper continues the study of a kernel family which uses the
Cauchy-Stieltjes kernel in place of the celebrated exponential kernel of the
exponential families theory. We extend the theory to cover generating measures
with support that is unbounded on one side. We illustrate the need for such an
extension by showing that cubic pseudo-variance functions correspond to
free-infinitely divisible laws without the first moment. We also determine the
domain of means, advancing the understanding of Cauchy-Stieltjes kernel
families also for compactly supported generating measures
On the experimental determination of the one-way speed of light
In this contribution the question of the isotropy of the one-way speed of
light from an experimental perspective is addressed. In particular, we analyze
two experimental methods commonly used in its determination. The analysis is
aimed at clarifying the view that the one-way speed of light cannot be
determined by techniques in which physical entities close paths. The procedure
employed here will provide epistemological tools such that physicists
understand that a direct measurement of the speed not only of light but of any
physical entity is by no means trivial. Our results shed light on the physics
behind the experiments which may be of interest for both physicists with an
elemental knowledge in special relativity and philosophers of science.Comment: 8 pages, 5 figures. To appear in the European Journal of Physic
USCID fourth international conference
Presented at the Role of irrigation and drainage in a sustainable future: USCID fourth international conference on irrigation and drainage on October 3-6, 2007 in Sacramento, California.Includes bibliographical references.This study, carried out between October 2004 and November 2005 on the island of Tenerife, covers: (1) characterization of the irrigated crops and quantification of the gross irrigation requirements (GIRs) of each crop using surveys; (2) field evaluation of drip/micro, spray and sprinkle irrigation systems to obtain global distribution uniformity (DU) as indicated by the Cal Poly ITRC (Irrigation Training and Research Centre, California Polytechnic State University, San Luis Obispo, California, USA); (3) analysis of on farm irrigation efficiency using local climatic data; and (4) inclusion of this data into a Geographic Information System (GIS). Crop GIRs show high deviations mainly because of the multiple microclimate conditions on the island, the irrigation methods used, the crop systems (greenhouses, etc) and the irrigation management. Field evaluation provided an average DU of 0.83 in drip/micro and spray irrigated banana crops, 0.69 in sprinkle irrigated ones, 0.58 in sprinkle irrigated horticulture and 0.81 for tomato crops (100% drip). Data showed that approximately 30% of the non-uniformity was due to pressure differences in the irrigation system, 3% due to unequal drainage, 7% due to unequal application rates, and 60% was due to other causes (which include manufacturing variation, plugging, and wear). Irrigation efficiency is around 80% in drip irrigated tomato and banana crops and 75% in sprinkle systems. Data showed that efficiency is slightly lower in greenhouses and mesh greenhouse crops than in non-protected crops basically due to the fact that although protected crops require less water, they receive an equal quantity of water. Inclusion of the data into a GIS makes possible a high level of agronomic water consumption control on the island
Economic feasibility of projects using triangular fuzzy numbers
© Springer Nature Switzerland AG 2018. The feasibility analysis of projects is an indispensable process for software development organizations. The intangible nature of software and the multiple criteria considered, introduce uncertainty in this process. This article proposes a method that uses triangular fuzzy numbers to evaluate traditional economic criteria Net Present Value, Internal Rate of Return, and Period of Recovery of Investment; which provides higher flexibility and certainty in the prediction. The article also presents the definitions of fuzzy economic criteria and discusses some variants for different cash flows. The proposal allows treating the variations that may occur during the life cycle of the project. The final value of the criteria is obtained by considering three possible scenarios: pessimistic, more accurate and optimistic. The proposal was applied experimentally, in 30 finished software projects. The target was to determine if there were significant differences in the order of feasibility of the projects, comparing the results obtained by the fuzzy economic criteria with those obtained by the traditional economic criteria. Significant differences were found in favor of the fuzzy economic criteria Net Present Value and Internal Rate of Return. Better results were achieved by fuzzy Period of Recovery of Investment, but, the difference was not statistically significant
Dual embedding of the Lorentz-violating electrodinamics and Batalin-Vilkovisky quantization
Modifications of the electromagnetic Maxwell Lagrangian in four dimensions
have been considered by some authors. One may include an explicit massive term
(Proca) and a topological but not Lorentz-invariant term within certain
observational limits.
We find the dual-corresponding gauge invariant version of this theory by
using the recently suggested gauge embedding method. We enforce this
dualisation procedure by showing that, in many cases, this is actually a
constructive method to find a sort of parent action, which manifestly
establishes duality. We also use the gauge invariant version of this theory to
formulate a Batalin-Vilkovisky quantization and present a detailed discussion
on the excitation spectrum.Comment: 8 page
Percepções dos alunos de Enfermagem sobre flipped classroom e avaliação contínua na sala de aula de Gestão de Enfermagem
Introduction: Although the training of nurses in administration and leadership has an important repercussion on the present and the future of the profession, teaching methods are still traditional in many cases. Flipped classroom is a widely used method in nursing education but studies about its application to Nursing Administration and Management are limited. Method: Qualitative study by means of anonymous survey (dichotomous and open questions). Results: 92 % of students were shown to be satisfied with the teaching methodology and 92.9 % with the assessment. Only 31.5 % had used it previously but 83 % would like to use it in more subjects. The students showed that the methodology used had improved their opinion about the content and had increased their perception its usefulness. Conclusion: The participating students have been shown to be satisfied with flipped method and continuous assessment. These teaching strategies can help motivate nursing students towards the subject of Nursing Administration and Management, which can encourage them to pursue postgraduate training and professional practice in this area.Introducción: Si bien la formación de enfermeros en Administración y Gestión tiene una importante repercusión en el presente y el futuro de la profesión, los métodos de enseñanza siguen siendo tradicionales en muchos casos. El aula invertida es un método ampliamente utilizado en la educación de enfermería, pero los estudios sobre su aplicación a la administración y gestión de enfermería son limitados. Método: Estudio cualitativo mediante cuestionario anónimo (preguntas dicotómicas y abiertas). Resultados: El 92 % de los estudiantes se mostró satisfecho con la metodología de enseñanza y el 92,9 % con la evaluación. Solo el 31,5 % lo había usado anteriormente, pero al 83 % le gustaría usarlo en más sujetos. Los estudiantes demostraron que la metodología utilizada había mejorado su opinión sobre el contenido y había aumentado su percepción útil del mismo. Conclusión: Los estudiantes participantes han demostrado estar satisfechos con el método de aula invertida. Estas estrategias de enseñanza pueden ayudar a motivar a los estudiantes de enfermería hacia la asignatura de Administración y Gestión de los Servicios de Enfermería, lo que puede animarlos a realizar una formación de posgrado y una práctica profesional en esta área.Introdução: Embora a educação de Enfermagem em Administração e Gestão tenha um grande impacto no presente e futuro da profissão, os métodos de ensino continuam a ser tradicionais em muitos casos. A sala de aula invertida é um método amplamente utilizado na educação em Enfermagem, mas os estudos sobre a sua aplicação à Administração e Gestão de Enfermagem são limitados. Método: Estudo qualitativo utilizando um questionário anônimo (perguntas dicotômicas e abertas). Resultados: 92% dos estudantes ficaram satisfeitos com a metodologia de ensino e 92,9% com a avaliação. Apenas 31,5% já o tinha utilizado antes, mas 83% gostariam de utilizá-lo em mais assuntos. Os estudantes mostraram que a metodologia utilizada havia melhorado a sua opinião sobre o conteúdo e aumentado a sua percepção útil do conteúdo. Conclusão: Os estudantes participantes mostraram-se satisfeitos com o método invertido e com a avaliação contínua. Estas estratégias de ensino podem ajudar a motivar os estudantes de Enfermagem para a disciplina de Administração e Gestão de Enfermagem, o que pode encorajá-los a empreender uma educação de pós-graduação e prática profissional nesta área
Marker-free transgenic rice lines with a defensin gene are potentially active against phytopathogenic fungus Sarocladium oryzae
In this work it was developed marker-free transgenic indica rice plants (cv J-104) by biolistic co-transformation and segregation approach. We attempted to express the NmDef02 antifungal defensin. Primary transformants were regenerated from embryogenic callus on culture medium with 50 mg/L hygromycin. Screening of hpt-marker-free transgenic lines was made by PCR in T1 progeny lines, germinated on semisolid medium without hygromycin. Relative expression of NmDef02 mRNA was examined by quantitative RT-PCR in marker-free T1 plants. In vitro antifungal test was performed by disk diffusion assay against Sarocladium oryzae. PCR assay verified that 15.12% of T1 plants were marker-free (NmDef02+/hpt−). RT-PCR analysis indicated that NmDef02 gene was successfully transcribed and the transgenic lines displayed different expression levels of the NmDef02 cDNA. Protein extracts of marker-free lines with high relative expression of NmDef02 inhibited fungus mycelial growth around disks. In contrast, it was confirmed fungus proliferation on disks impregnated with protein extracts of non-transgenic plants. The results of the present work demonstrated that the expression of the NmDef02 defensin in transgenic rice plants is effective against the phytopathogenic fungus Sarocladium oryzae under in vitro conditions. Thus, NmDef02 defensin could be a useful tool for J-104 rice improvement
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