1,375 research outputs found
Qmethod: A package to explore human perspectives using Q methodology
Q is a methodology to explore the distinct subjective perspectives that exist within a group. It is used increasingly across disciplines. The methodology is semi-qualitative and the data are analysed using data reduction methods to discern the existing patterns of thought. This package is the first to perform Q analysis in R, and it provides many advantages to the existing software: namely, it is fully cross-platform, the algorithms can be transparently examined, it provides results in a clearly structured and tabulated form ready for further exploration and modelling, it produces a graphical summary of the results, and it generates a more concise report of the distinguishing and consensus statements. This paper introduces the methodology and explains how to use the package, its advantages as well as its limitations. I illustrate the main functions with a dataset on value patterns about democracy.During the development of this package, the author was funded by the Department of Research of the Basque Government. The author is grateful to Steven Brown and Peter Schmolck for making Q datasets publicly available and for allowing the Lipset dataset to be used in this R package; to Laurent Gatto for his advice in developing it; and to Ben Fried, two anonymous reviewers, and the editor for their useful comments on the manuscript.This is the final published version of the article. It was originally published in The R Journal (Zabala A, The R Journal, 2014, 6(2),163-173). The final version is available at http://journal.r-project.org/archive/2014-2/zabala.pd
Electron correlations, spontaneous magnetization and momentum density in quantum dots
The magnetization of quantum dots is discussed in terms of a relatively
simple but exactly solvable model Hamiltonian. The model predicts oscillations
in spin polarization as a function of dot radius for a fixed electron density.
These oscillations in magnetization are shown to yield distinct signature in
the momentum density of the electron gas, suggesting the usefulness of momentum
resolved spectroscopies for investigating the magnetization of dot systems. We
also present variational quantum Monte Carlo calculations on a square dot
containing 12 electrons in order to gain insight into correlation effects on
the interactions between like and unlike spins in a quantum dot.Comment: 6 pages, 4 figure
Target Geometry Dependence of Electron Energy Loss Spectra in Scanning Transmission Electron Microscopy (STEM)
In the frame of the Self-Energy formalism, we study the interaction between STEM electrons and small particles in the range of the valence electron excitations. We first calculate the energy loss probability for an isolated sphere and study the loss spectrum dependence on the size of the particle and on the relative impact parameter. Then we analyze the loss spectra in more realistic situations: (a) the effect of the coupling between the particle and supporting surface is studied in a simple geometrical model; and (b) we analyze the dependence of the losses on the geometrical shape of the target by considering hemispherical particle. Our results are in a good qualitative (and in simple cases, quantitative too) agreement with several experimental results which show anomalous excitations. We restate the suitability of the dielectric theory to study the surface excitations of these systems
Precolonial institutions and deforestation in Africa
We find that local institutions inherited from the precolonial era continue to play an important role in natural resource governance in Africa. Using satellite image data, we find a significant and robust relationship between deforestation and precolonial succession rules of local leaders (local chiefs). In particular, we find that those precolonial areas where local leaders were appointed by ‘social standing’ have higher rates of deforestation compared to the base case of hereditary rule and where local leaders were appointed from above (by paramount chiefs). While the transmission mechanisms behind these results are complex, we suggest that areas where local leaders were appointed by social standing are more likely to have poorer institutions governing local leadership and forest management.This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.landusepol.2015.10.03
Conclusiones
El tema general que aglutina los trabajos presentados en este volumen pobreza, exclusión social y discriminación étnico-racial en América Latina y el Caribe ha sido abordado por los autores en sus múltiples interrelaciones, destacándose en todos el rol de la discriminación étnico-racial en los procesos de producción y reproducción de pobreza. De tal manera, los temas específicos tratados, a saber, discriminación laboral, género y familia, cultura e identidad, implicaciones sociales y políticas, más que un diagnóstico de la problemática en la región, han dado cuenta de las múltiples interrelaciones existentes entre esos fenómenos, y de las diversas aristas que ellos suponen para la investigación y transformación social.
Los retos que quedan planteados para la continuidad en el estudio y discusión sobre los temas de pobreza, exclusión social y discriminación étnico-racial en América Latina y el Caribe pueden resumirse en los siguientes: desarrollo de estudios comparativos en la región; logro de mayor vínculo e incidencia en la esfera de la toma de decisiones; profundización en el análisis de las diversas experiencias de desarrollo en la región y de los impactos específicos de las políticas y programas sociales; y consideración de los criterios y propuestas de los actores sociales involucrados, así como de la sociedad civil
Magnetism in Atomic-Sized Palladium Contacts and Nanowires
We have investigated Pd nanowires theoretically, and found that, unlike
either metallic or free atomic Pd, they exhibit Hund's rule magnetism. In long,
monoatomic wires, we find a spin moment of 0.7 Bohr magnetons per atom, whereas
for short, monoatomic wires between bulk leads, the predicted moment is about
0.3 Bohr magnetons per wire atom. In contrast, a coaxial (6,1) wire was found
to be nonmagnetic. The origin of the wire magnetism is analyzed.Comment: 6 pages, including 4 figure
Revisión de la literatura sobre estudios de juventud rural en América Latina y el Caribe durante 2001-2019
This literature review includes 45 research studies focused on Latin American rural youth. The studies were published in peer-reviewed research journals between 2001-2019. The analysis is divided into study approaches, methods, participants, and findings. Four research approaches were identified: 1) rural youth migration, 2) education and/or communication, 3) expectations or future perspectives of the rural youth, and 4) rural youth characterization. Although traditional definitions of youth use an age range of 14-25 years, a broad criterion for selecting participants was observed. Regarding methods, the studies used quantitative, qualitative, and mixed-method analyses; however, in some cases, elements such as the qualitative research approach, the statistical representativeness (for quantitative studies), and the triangulation strategy in the mixed-method analysis were not mentioned or followed. The findings of the four research approaches coincided with the fact that the rural contexts in Latin America create socioeconomic barriers for rural youth development; therefore, rural youth aspirations are more focused on urban activities. In addition, some authors highlighted the importance of education or extension programs developed by local governments to empower rural youth in Latin America.Esta revisión de la literatura se basó en 45 estudios de investigación que se enfocaron en la juventud rural latinoamericana. Dichos estudios fueron publicados en revistas arbitradas entre 2001 y 2019. El análisis de los documentos se dividió en enfoques de investigación, métodos utilizados, participantes y principales hallazgos. Se identificaron cuatro enfoques de investigación: 1) migración rural juvenil, 2) educación y/o comunicación para juventud rural, 3) expectativas y perspectivas de la juventud rural y 4) caracterizaciones de la juventud rural. Aunque las definiciones tradicionales de juventud utilizan rangos de edad entre 14 y 25 años, se observó un concepto ampliado dentro de los estudios analizados. Con respecto a los métodos, los estudios utilizaron estrategias cuantitativas, cualitativas y de métodos mixtos. Sin embargo, en algunos casos, no se desarrollaron o se mencionaron elementos como el enfoque de investigación cualitativa, la representatividad estadística (para estudios cuantitativos) o la triangulación en el análisis mixto. Por último, se observó que los cuatro enfoques de investigación coinciden en que el contexto rural latinoamericano impone barreras para la juventud; por tanto, sus aspiraciones están más orientadas hacia las actividades urbanas. Además, algunos autores subrayaron la importancia de la educación y la extensión para el empoderamiento de la juventud rural en América Latina
Payments for Pioneers? Revisiting the Role of External Rewards for Sustainable Innovation under Heterogeneous Motivations
© 2017, Elsevier Acknowledging the diversity of preferences, goals and motivations of individuals is key to promote the effectiveness of incentive-based conservation interventions. This paper analyses the heterogeneity of motivations to adopt silvopastoral practices, a social-ecological innovation for soil conservation and carbon emission reduction. We use Q methodology to identify smallholders' views with regard to these practices in a community in the forest frontier in Chiapas (Mexico). The analysis uncovers three main perspectives: self-sufficient pioneers, environmentally-conscious followers and payment-dependent conservatives. We discuss these perspectives around three topics: smallholders' predisposition to adopt silvopastoral practices, their views about needing external payments to sustain their livelihood and the diffusion of innovative sustainable practices. We relate these perspectives with livelihood characteristics and with observed adoption levels under a pilot programme to promote silvopasture. Our findings suggest that incentives other than payments may be more appropriate for those more likely to adopt, and that payments could encourage rent-seeking strategies and not necessarily promote permanent behavioural change. We suggest ways for designing more effective and adaptive environmental conservation programmes to foster adoption and continuation of social-ecological innovations
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