Engaging without over-powering: A case study of a FLOSS project

This is the post-print version of the published chapter. The original publication is available at the link below. Copyright @ 2010 IFIP International Federation for Information Processing.The role of Open Source Software (OSS) in the e-learning business has become more and more fundamental in the last 10 years, as long as corporate and government organizations have developed their educational and training programs based on OSS out-of-the-box tools. This paper qualitatively documents the decision of the largest UK e-learning provider, the Open University, to adopt the Moodle e-learning system, and how it has been successfully deployed in its site after a multi-million investment. A further quantitative study also provides evidence of how a commercial stakeholder has been engaged with, and produced outputs for, the Moodle community. Lessons learned from this experience by the stakeholders include the crucial factors of contributing to the OSS community, and adapting to an evolving technology. It also becomes evident how commercial partners helped this OSS system to achieve the transition from an “average” OSS system to a successful multi-site, collaborative and community-based OSS project

The hydrological regime of a forested tropical Andean catchment.

The hydrology of tropical mountain catchments plays a central role in ecological function, geochemical and biogeochemical cycles, erosion and sediment production, and water supply in globally important environments. There have been few studies quantifying the seasonal and annual water budgets in the montane tropics, particularly in cloud forests. We investigated the water balance and hydrologic regime of the Kosñipata catchment (basin area: 164.4 km2) over the period 2010–2011. The catchment spans over 2500 m in elevation in the eastern Peruvian Andes and is dominated by tropical montane cloud forest with some high-elevation puna grasslands. Catchment-wide rainfall was 3112 ± 414 mm yr−1, calculated by calibrating Tropical Rainfall Measuring Mission (TRMM) 3B43 rainfall with rainfall data from nine meteorological stations in the catchment. Cloud water input to streamflow was 316 ± 116 mm yr−1 (9.2% of total inputs), calculated from an isotopic mixing model using deuterium excess (Dxs) and δD of waters. Field streamflow was measured in 2010 by recording height and calibrating to discharge. River run-off was estimated to be 2796 ± 126 mm yr−1. Actual evapotranspiration (AET) was 688 ± 138 mm yr−1, determined using the Priestley and Taylor–Jet Propulsion Laboratory (PT-JPL) model. The overall water budget was balanced within 1.6 ± 13.7%. Relationships between monthly rainfall and river run-off follow an anticlockwise hysteresis through the year, with a persistence of high run-off after the end of the wet season. The size of the soil and shallow groundwater reservoir is most likely insufficient to explain sustained dry-season flow. Thus, the observed hysteresis in rainfall–run-off relationships is best explained by sustained groundwater flow in the dry season, which is consistent with the water isotope results that suggest persistent wet-season sources to streamflow throughout the year. These results demonstrate the importance of transient groundwater storage in stabilising the annual hydrograph in this region of the Andes

A case study of the Neti Pot’s rise, americanization, and rupture as integrative medicine in U.S. media discourse

In a period of only one decade in the United States, the neti pot shifted from obscure Ayurvedic health device to mainstream complementary and integrative medicine (CIM), touted by celebrities and sold widely in drug stores. We examine the neti pot as a case study for understanding how a foreign health practice became mainstreamed, and what that process reveals about more general discourses of health in the United States. Using discourse analysis of U.S. popular press and new media news (1999–2012) about the neti pot, we trace the development of discourses from neti’s first introduction in mainstream news, through the hype following Dr. Oz’s presentation on Oprah, to 2011 when two adults tragically died after using Naegleria fowleri amoeba-infested tap water in their neti pots. Neti pot discourses are an important site for communicative analysis because of the pot’s complexity as an intercultural artifact: Neti pots and their use are enfolded into the biomedical practice of nasal irrigation and simultaneously Orientalized as exotic/magical and suspect/dangerous. This dual positioning as normal and exotic creates inequitable access for using the neti pot as a resource for increasing cultural health capital (CHC). This article contributes to work that critically theorizes the transnationalism of CIM, as the neti pot became successfully Americanized. These results have implications for understanding global health practices’ incorporation or co-optation in new contexts, and the important role that popularly mediated health communication can play in framing what health care products and practices mean for consumers

Covariant N=2 heterotic string in four dimensions

We construct a covariant formulation of the heterotic superstring on K3 times T^2 with manifest N=2 supersymmetry. We show how projective superspace appears naturally in the hybrid formulation giving a (partially) geometric interpretation of the harmonic parameter. The low-energy effective action for this theory is given by a non-standard form of N=2 supergravity which is intimately related to the N=1 old-minimal formulation. This formalism can be used to derive new descriptions of interacting projective superspace field theories using Berkovits' open string field theory and the the heterotic Berkovits-Okawa-Zwiebach construction.Comment: 11+3 page

Graphene Synthesis Using a CVD Reactor and a Discontinuous Feed of Gas Precursor at Atmospheric Pressure

The present work shows a new method in order to cost-effectively achieve the synthesis of graphene by Chemical Vapor Deposition (CVD). Unlike most usual processes, where precursors such as argon, H2, CH4, and high purity copper foil are used, the proposed method has replaced the previous ones by N2, N2 (90%) : H2 (10%), C2H2, and electrolytic copper (technical grade) since the use of industrialized precursors helps reduce production costs. On the other hand, the process was modified from a continuous flow system with vacuum to a discontinuous one at atmospheric pressure, eliminating the use of vacuum pump. In addition, this modification optimized the consumption of gases, which reduced the waste and the emission of pollutant gases into the atmosphere. Graphene films were grown under different gas flowrates and temperatures. Then, the obtained material was characterized by TEM, Raman spectroscopy, and AFM, confirming the presence of few graphene layers. In brief, the growth time was reduced to six minutes with acetylene as a carbon precursor at 1000°C and at atmospheric pressure, with a flow rate of 30 sccm. Finally, the reported conditions can be used for the synthesis of good quality graphene films in industrial applications

Overview of experimental results in PbPb collisions at sqrt{s_NN} = 2.76 TeV by the CMS Collaboration

The CMS experiment at the LHC is a general-purpose apparatus with a set of large acceptance and high granularity detectors for hadrons, electrons, photons and muons, providing unique capabilities for both proton-proton and ion-ion collisions. The data collected during the November 2010 PbPb run at sqrt{s_NN} = 2.76 TeV was analyzed and multiple measurements of the properties of the hot and dense matter were obtained. Global event properties, detailed study of jet production and jet properties, isolated photons, quarkonia and weak bosons were measured and compared to pp data and Monte Carlo simulations.Comment: 8 pages, 10 figures, proceedings for Quark Matter 2011, Annecy, France, May 23-28, 201

An extreme proto-cluster of luminous dusty starbursts in the early Universe

We report the identification of an extreme proto-cluster of galaxies in the early Universe whose core (nicknamed Distant Red Core, DRC) is formed by at least ten dusty star-forming galaxies (DSFGs), confirmed to lie at $z_{\rm spec} = 4.002$ via detection of [CI](1-0), $^{12}$CO(6-5), $^{12}$CO(4-3), $^{12}$CO(2-1) and ${\rm H_2O} (2_{11} - 2_{02})$ emission lines, detected using ALMA and ATCA. The spectroscopically-confirmed components of the proto-cluster are distributed over a ${\rm 260\, kpc \times 310\, kpc}$ region and have a collective obscured star-formation rate (SFR) of $\sim 6500 \, M_\odot \, {\rm yr}^{-1}$, considerably higher than has been seen before in any proto-cluster of galaxies or over-densities of DSFGs at $z \gtrsim 4$. Most of the star formation is taking place in luminous DSFGs since no Ly$\alpha$ emitters are detected in the proto-cluster core, apart from a Ly$\alpha$ blob located next to one of the DRC dusty components and extending over $60\,{\rm kpc}$. The total obscured SFR of the proto-cluster could rise to ${\rm SFR} \sim 14,400 \, M_\odot \, {\rm yr}^{-1}$ if all the members of an over-density of bright DSFGs discovered around DRC in a wide-field LABOCA 870-$\mu$m image are part of the same structure. The total halo mass of DRC could be as high as $\sim 4.4 \times 10^{13}\,M_\odot$ and could be the progenitor of a Coma-like cluster at $z = 0$. The relatively short gas-depletion times of the DRC components suggest either the presence of a mechanism able to trigger extreme star formation simultaneously in galaxies spread over a few hundred kpc or the presence of gas flows from the cosmic web able to sustain star formation over several hundred million years.Comment: Submitted to ApJ. Minor updates added, including a change of the source name. Comments welcom

Fatores protetores da depressão em uma mostra de adultos maiores em Porto Rico: auto eficácia, escolaridade e outras variáveis sócio demográficas

The aim of this descriptive-correlational study was to assess the relationship between self-efficacy, educational level and depressive symptoms in order to identify protective factors for depression in a sample of elderly people in Puerto Rico. Other socio-demographic variables such as marital status, living arrangements, and sex were examined in relation to self-efficacy and depressive symptoms. The selected sample consisted of 45 participants ranging in age from 60 to 86 years old (M=69; SD=7.37). Measures employed included the Zung Self-Rating Depression Scale (1965) and the Baessler and Schwarcer's General Self-Efficacy Scale (1996). The hypothesis stated that the level of depressive symptoms would be lower when there is higher self-efficacy and higher educational level in a sample of Puerto Rican elderly people. Statistical analysis included t tests, the Pearson Correlation Coefficient and Multiple Regression Coefficient. Statistically significant differences for selfefficacy and educational level were found between those who did not show depressive symptoms and those with moderate to severe depression. In addition, higher levels of depression and lower levels of self-efficacy were found in those who had widowed. Results suggest that high levels of education and self-efficacy are protective factors for depression in elderly people, while widowhood is a risk factor for depression.O objetivo desta pesquisa descritiva-correlacional foi avaliar a relação entre auto eficácia, escolaridade e síntomas depressivos para identificar fatores protetores da depressão em uma mostra de pessoas de idade avançada da população de Porto Rico. Além disso, foram examinadas outras variáveis sócio demográficas como o estado civil, com quem residem e o sexo, com relação à auto eficácia e os sintomas depressivos. Selecionaram-se por disponibilidade 45 participantes com idades entre 60 e 86 anos (M=69; DE=7.37). Os instrumentos utilizados foram a Escala Auto-avaliativa da Depressão de Zung (1965) e a Escala de Auto eficácia Geral de Baessler e Schwarcer (1996). A hipótese propôs que, a maior auto eficácia e escolaridade, menor seria o nível dos sintomas depressivos em uma mostra de adultos maiores de Porto Rico. As análises estatísticas incluíram testes t e os Coeficientes de Correlação de Pearson e de Regressão Múltipla. Foram encontradas diferenças estatisticamente significativas para a auto eficácia e a escolaridade entre os que não apresentavam depressão e os que apresentavam depressão moderada ou severa. Além disso encontraram-se maiores níveis de depressão e menores níveis de auto eficácia nos que haviam enviuvado. Os resultados sugerem que altos níveis de escolaridade e auto eficácia são fatores protetores da depressão nos adultos maiores, enquanto que a viuvez é um fator de risco para depressão.El objetivo de esta investigación descriptiva-correlacional fue evaluar la relación entre autoeficacia, escolaridad y síntomas depresivos para identificar factores protectores de la depresión en una muestra de personas de edad avanzada de la población de Puerto Rico. Además, se examinaron otras variables sociodemográficas como el estado civil, con quién residen y el sexo, en relación con la autoeficacia y los síntomas depresivos. Se seleccionaron por disponibilidad 45 participantes con edades entre 60 y 86 años (M=69; DE=7.37). Los instrumentos utilizados fueron la Escala Autoevaluativa de la Depresión de Zung (1965) y la Escala de Autoeficacia General de Baessler y Schwarcer (1996). La hipótesis planteó que, a mayor autoeficacia y escolaridad, menor sería el nivel de los síntomas depresivos en una muestra de adultos mayores de Puerto Rico. Los análisis estadísticos incluyeron pruebas t y los Coeficientes de Correlación de Pearson y de Regresión Múltiple. Se encontraron diferencias estadísticamente significativas para la autoeficacia y la escolaridad entre quienes no presentaban depresión y los que presentaban depresión moderada o severa. Además, se encontraron mayores niveles de depresión y menores niveles de autoeficacia en quienes habían enviudado. Los resultados sugieren que altos niveles de escolaridad y autoeficacia son factores protectores de la depresión en los adultos mayores, mientras que la viudez es un factor de riesgo para la depresión

Magnetism of small V clusters embedded in a Cu fcc matrix: an ab initio study

We present extensive first principles density functional theory (DFT) calculations dedicated to analyze the magnetic and electronic properties of small V$_{n}$ clusters (n=1,2,3,4,5,6) embedded in a Cu fcc matrix. We consider different cluster structures such as: i) a single V impurity, ii) several V$_{2}$ dimers having different interatomic distance and varying local atomic environment, iii) V$_{3}$ and iv) V$_{4}$ clusters for which we assume compact as well as 2- and 1-dimensional atomic configurations and finally, in the case of the v) V$_{5}$ and vi) V$_{6}$ structures we consider a square pyramid and a square bipyramid together with linear arrays, respectively. In all cases, the V atoms are embedded as substitutional impurities in the Cu network. In general, and as in the free standing case, we have found that the V clusters tend to form compact atomic arrays within the cooper matrix. Our calculated non spin-polarized density of states at the V sites shows a complex peaked structure around the Fermi level that strongly changes as a function of both the interatomic distance and local atomic environment, a result that anticipates a non trivial magnetic behavior. In fact, our DFT calculations reveal, in each one of our clusters systems, the existence of different magnetic solutions (ferromagnetic, ferrimagnetic, and antiferromagnetic) with very small energy differences among them, a result that could lead to the existence of complex finite-temperature magnetic properties. Finally, we compare our results with recent experimental measurements.Comment: 7 pages and 4 figure

D-instantons and twistors: some exact results

We present some results on instanton corrections to the hypermultiplet moduli space in Calabi-Yau compactifications of Type II string theories. Previously, using twistor methods, only a class of D-instantons (D2-instantons wrapping A-cycles) was incorporated exactly and the rest was treated only linearly. We go beyond the linear approximation and give a set of holomorphic functions which, through a known procedure, capture the effect of D-instantons at all orders. Moreover, we show that for a sector where all instanton charges have vanishing symplectic invariant scalar product, the hypermultiplet metric can be computed explicitly.Comment: 32 pages, 3 figures, uses JHEP3.cls; some changes in section 3.3.3; corrected formula for the contact potentia