bluuebunny/crossref_metadata_2025 huggingface dataset:
Letters to leaders: Comments on the Zero Draft of Rio+20 outcome document
Authors: Luxembourg Caritas , Schneider Norry
Published: September 2012

The first version of the declaration (“Outcome Document”) for the United Nations Conference on Sustainable Development (UNCSD or ”Rio+20”), the “Zero Draft”, was released by the UNCSD Secretariat in January 2012. The 19-page document is based on a compilation of inputs received from United Nations (UN) member States and other stakeholders, and it outlines a vision for building a sustainable world. This piece is part of a Caritas Luxembourg position paper sent early February 2012 to the Ministry for sustainable development and infrastructure of the Grand Duchy of Luxembourg (Ministère du Développement Durable et des Infrastructures, or MDDI), in order to inform Luxembourgish government’s position on sustainable development prior to the Rio+20 conference.
The elusive quest? African regionalism, social cohesion, and institutions
Authors: Compton Robert
Published: September 2012

Gruzd, S. (Ed.). (2010). Grappling with governance: Perspectives on the African peer review mechanism.

Akokpari, J., Ndinga-Muvumba, A., & Murithi, T. (2008). The African Union and its institutions.

Ferguson, J. (2006). Global shadows: Africa in the neoliberal world order.

Maathai, W. (2009). The challenge for Africa.
Internet and Gaming Addiction: A Systematic Literature Review of Neuroimaging Studies
Authors: Kuss Daria J. , Griffiths Mark D.
Published: September 2012

In the past decade, research has accumulated suggesting that excessive Internet use can lead to the development of a behavioral addiction. Internet addiction has been considered as a serious threat to mental health and the excessive use of the Internet has been linked to a variety of negative psychosocial consequences. The aim of this review is to identify all empirical studies to date that used neuroimaging techniques to shed light upon the emerging mental health problem of Internet and gaming addiction from a neuroscientific perspective. Neuroimaging studies offer an advantage over traditional survey and behavioral research because with this method, it is possible to distinguish particular brain areas that are involved in the development and maintenance of addiction. A systematic literature search was conducted, identifying 18 studies. These studies provide compelling evidence for the similarities between different types of addictions, notably substance-related addictions and Internet and gaming addiction, on a variety of levels. On the molecular level, Internet addiction is characterized by an overall reward deficiency that entails decreased dopaminergic activity. On the level of neural circuitry, Internet and gaming addiction led to neuroadaptation and structural changes that occur as a consequence of prolonged increased activity in brain areas associated with addiction. On a behavioral level, Internet and gaming addicts appear to be constricted with regards to their cognitive functioning in various domains. The paper shows that understanding the neuronal correlates associated with the development of Internet and gaming addiction will promote future research and will pave the way for the development of addiction treatment approaches.
Extraction of Volatile Oil from Aromatic Plants with Supercritical Carbon Dioxide: Experiments and Modeling
Authors: Coelho Jose P. , Cristino Ana F. , Matos Patrícia G. , Rauter Amélia P. , Nobre Beatriz P. , Mendes Rui L. , Barroso João G. , Mainar Ana , Urieta Jose S. , Fareleira João M. N. A. , Sovová Helena , Palavra António F.
Published: September 2012

An overview of the studies carried out in our laboratories on supercritical fluid extraction (SFE) of volatile oils from seven aromatic plants: pennyroyal (Mentha pulegium L.), fennel seeds (Foeniculum vulgare Mill.), coriander (Coriandrum sativum L.), savory (Satureja fruticosa Béguinot), winter savory (Satureja montana L.), cotton lavender (Santolina chamaecyparisus) and thyme (Thymus vulgaris), is presented. A flow apparatus with a 1 L extractor and two 0.27 L separators was built to perform studies at temperatures ranging from 298 to 353 K and pressures up to 30.0 MPa. The best compromise between yield and composition compared with hydrodistillation (HD) was achieved selecting the optimum experimental conditions of extraction and fractionation. The major differences between HD and SFE oils is the presence of a small percentage of cuticular waxes and the relative amount of thymoquinone, an oxygenated monoterpene with important biological properties, which is present in the oils from thyme and winter savory. On the other hand, the modeling of our data on supercritical extraction of volatile oil from pennyroyal is discussed using Sovová’s models. These models have been applied successfully to the other volatile oil extractions. Furthermore, other experimental studies involving supercritical CO2 carried out in our laboratories are also mentioned.
Video Game Genre Affordances for Physics Education
Authors: Anagnostou Kostas , Pappa Anastasia
Published: September 2012

In this work, the authors analyze the video game genres’ features and investigate potential mappings to specific didactic approaches in the context of Physics education. To guide the analysis, the authors briefly review the main didactic approaches for Physics and identify qualities that can be projected into game features. Based on the characteristics of the didactic approaches each video game genre’s potential for narration and simulation and affordances for reflection and assessment are evaluated, providing examples of specific games that adhere to those requirements and ways they can be utilized in educational contexts. The paper concludes by discussing the implications on serious game design and integration of games for Physics education in school environments and suggests topics for future research.
Encouraging Engagement in Game-Based Learning
Authors: Whitton Nicola
Published: September 2012

It is a common misconception that game-based learning is, by its very nature, engaging for the majority of learners. This is not necessarily the case, particularly for learners in Higher Education who may need to be persuaded of the value of learning games. For some learners, games may simply not be perceived as engaging–either in terms of an initial motivation to play or sustained participation. This paper describes the Alternate Reality Games for Orientation, Socialisation and Induction (ARGOSI) project, which experienced unexpectedly low motivation and participation. Despite extensive marketing, only a small fraction of potential students participated in the game and of those a far smaller number were highly engaged. Evidence from the project is presented and the reasons for the lack of engagement in the game created are considered. Finally the paper reflects on ways in which engagement with game-based learning might be encouraged.
Affordances and Constraints of Scaffolded Learning in a Virtual World for Young Children
Authors: Black Rebecca W. , Reich Stephanie M.
Published: September 2012

In recent years there has been a marked increase in the number of virtual worlds aimed at populations between the ages of 6 to14 years. This article examines the content and design of one such site, Webkinz World, as a sociocultural context for informal learning. Focusing on the design and activities of this site sheds light on the ways in which Webkinz World supports learning, especially for nascent users, and the apparent limits of these support structures as users gain more expertise.
Digital Games
Authors: Pivec Paul , Pivec Maja
Published: September 2012

Digital Games are becoming a new form of interactive content and game playing provides an interactive and collaborative platform for learning purposes. Collaborative learning allows participants to produce new ideas as well as to exchange information, simplify problems, and resolve the tasks. Context based collaborative learning method is based on constructivist learning theory and guides the design of the effective learning environments. The constructivist design required for successful Game-Based Learning is discussed in this chapter and the model of recursive learning is discussed suggesting how Game-Based Learning (GBL) and how to maximize its affect. This chapter defines “Gameplay” and tables the perceptions of both players and teachers in the area of abilities learnt from playing digital games. Resources for implementing GBL are highlighted and the need for these is discussed. We conclude this chapter with design guidelines that will ensure effective learning outcomes are attained and suggest why these steps are necessary.
Understanding Computational Thinking before Programming
Authors: Kazimoglu Cagin , Kiernan Mary , Bacon Liz , MacKinnon Lachlan
Published: September 2012

This paper outlines an innovative game-based approach to learning introductory programming that is grounded in the development of computational thinking at an abstract conceptual level, but also provides a direct contextual relationship between game-play and learning traditional introductory programming. The paper proposes a possible model for, and guidelines in support of, this games-based approach contextualized by an analysis of existing research into the issues of learning programming and game based learning approaches. Furthermore, the proposed game-based learning model focuses not only on procedural and applied knowledge and associated skills acquisition in computational thinking, but also provides contextualised theoretical knowledge on Computer Science concepts. By way of illustration, the authors introduce a game prototype currently being developed to combine a puzzle solving game-play that uses Computer Science concepts as the game elements.
Word Sense Disambiguation
Authors: Bhattacharyya Pushpak , Khapra Mitesh
Published: September 2012

This chapter discusses the basic concepts of Word Sense Disambiguation (WSD) and the approaches to solving this problem. Both general purpose WSD and domain specific WSD are presented. The first part of the discussion focuses on existing approaches for WSD, including knowledge-based, supervised, semi-supervised, unsupervised, hybrid, and bilingual approaches. The accuracy value for general purpose WSD as the current state of affairs seems to be pegged at around 65%. This has motivated investigations into domain specific WSD, which is the current trend in the field. In the latter part of the chapter, we present a greedy neural network inspired algorithm for domain specific WSD and compare its performance with other state-of-the-art algorithms for WSD. Our experiments suggest that for domain-specific WSD, simply selecting the most frequent sense of a word does as well as any state-of-the-art algorithm.
Interactive Question Answering
Authors: Konstantinova Natalia , Orasan Constantin
Published: September 2012

The increasing amount of information available online has led to the development of technologies that help to deal with it. One of them is Interactive Question Answering (IQA), a research field that has emerged at the intersection of question answering and dialogue systems, and which allows users to find the answers to questions in an interactive way. During the answering process, the automatic system can initiate a dialogue with the user in order to clarify missing or ambiguous information, or suggest further topics for discussion. This chapter presents the state-of-the-art in the field of interactive question answering. Given that IQA inherits a lot of features from dialogue systems and question answering, these fields are also briefly presented. Analysis of the existing systems reveals that in general IQA systems rely on a scaled-down version of a dialogue system, sometimes built on top of question answering systems. Evaluation of IQA is also discussed, showing that it combines evaluation techniques from question answering and dialogue systems.
Mining User-Generated Content for Social Research and Other Applications
Authors: Banchs Rafael E. , Penagos Carlos G. Rodríguez
Published: September 2012

The main objective of this chapter is to present a general overview of the most relevant applications of text mining and natural language processing technologies evolving and emerging around the Web 2.0 phenomenon (such as automatic categorization, document summarization, question answering, dialogue management, opinion mining, sentiment analysis, outlier identification, misbehavior detection, and social estimation and forecasting) along with the main challenges and new research opportunities that are directly and indirectly derived from them.
A Cross-Cultural Measure of Servant Leadership Behaviors
Authors: Hale Jeff R. , Fields Dail
Published: September 2012

This chapter presents items comprising three scales that measure servant leadership using three key dimensions: service, humility, and vision. The instrument was used to measure servant leadership behaviors experienced by followers in the United States and Ghana. Reliability and validity evidence is included from two research studies. A discussion of the relationship of servant leadership behaviors with employee outcomes assessed in these studies concludes the chapter.
Software as a Service (SaaS)
Authors: Brown Cecelia Wright , Nyarko Kofi
Published: September 2012

SaaS, short for Software-as-a-Service, is quickly becoming the dominant approach for software delivery as a Web-based service. It is a software deployment model in which an enterprise application is delivered and managed as a service by a software vender to simultaneously meet the needs of multiple customers. By enabling remote access to software and its associated functions, SaaS allows organizations and individuals to access business and commercial functionality at a cost typically less than paying for licensed applications. The purpose of this chapter is to discuss the origin and evolution of SaaS, as well as to describe its roll in today’s enterprise environment. This chapter begins with a description of the evolution of SaaS, followed by the architecture, implementation, and associated business model.
The Legal Implications of Cloud Computing
Authors: Kemp Michael L. , Robb Shannon , Deans P. Candace
Published: September 2012

The purpose of this chapter is to examine the current legal environment of cloud computing. As the cloud platform continues to evolve, companies will find the need to address the business risks, particularly legal issues which will be of paramount concern. This chapter discusses the legal dimensions of cloud computing from the perspective of three L’s: Location, Litigation, and Liability. Most of the current issues can be evaluated as part of one of these categories. Although the legal aspects of the cloud lag behind the business and technology side, prior case law is discussed as it applies to issues arising from various implementations of cloud computing applications. This discussion provides a road map for CIOs and other managers as they deal with emerging issues and legal ramifications of cloud computing. The chapter also provides direction for research in this realm.
Open Source for Higher Conventional and Open Education in India
Authors: Sharma Ramesh C.
Published: September 2012

Distance Education in India has come a long way since the launch of correspondence courses in 1962 at the Delhi University. There have been many changes over the period of time, and thus, a transition was observed from print based correspondence courses to media supported distance education. With the advent of technology, expansion of telephone network, and lowering of tariff, there has been expansion of e-learning services, web based education, and mobile learning. Currently there are around 600 conventional (face-to-face) universities in India serving around 1.2 billion students. Starting with one Open University in 1982, now we have 15 open universities. There are single mode and dual mode distance education institutions. These provide instructions from print based to technology enabled means. All these developments transformed the teaching learning. Many of the institutions followed Open Educational Resources and Open Source movement. Reasons are varied for adopting open source. With the purpose to reduce the costs on software development, freedom to improve the software and freedom to redistribute to help neighbours has made individuals, institutions, and governments support open source. In this chapter, the author examines some of the initiatives of Open Source in the field of higher, open and distance education in India.
Genetic Characterization of Atypical Mansonella (Mansonella) ozzardi Microfilariae in Human Blood Samples from Northeastern Peru
Authors: Marcos Luis A. , Arrospide Nancy , Recuenco Sergio , Cabezas Cesar , Weil Gary J. , Fischer Peter U.
Published: September 2012

DNA sequence comparisons are useful for characterizing proposed new parasite species or strains. Microfilariae with an atypical arrangement of nuclei behind the cephalic space have been recently described in human blood samples from the Amazon region of Peru. Three blood specimens containing atypical microfilariae were genetically characterized using three DNA markers (5S ribosomal DNA, 12S ribosomal DNA, and cytochrome oxidase I). All atypical microfilariae were clustered into the Mansonella group and indistinguishable from M. ozzardi based on these DNA markers.
High Household Economic Burden Caused by Hospitalization of Patients with Severe Dengue Fever Cases in Can Tho Province, Vietnam
Authors: Tam Pham Thi , Dat Nguyen Tan , Huu Le Minh , Thi Xuan Cuc Pham , Duc Hoang Minh , Tu Tran Cong , Kutcher Simon , Ryan Peter A. , Kay Brian H.
Published: September 2012

During 2006–2007, a cohort of 144 confirmed dengue cases in Can Tho Province, Vietnam were compared with a matching set of 144 households that had no dengue cases. Approximately 6–9 months after sickness, there were no significant differences in terms of knowledge of the etiology of dengue, mosquito breeding habitats, and prevention measures in respondents from both sets of households. There was also no difference in the abundance of Aedes aegypti (Linn.) adults but the average numbers of late instar and pupal Ae. aegypti per household were greater in the negative control houses. Thus, the risk seemed to be no higher in case households, although it is conceivable that changes may have occurred in either group over the intervening period. The average cost for a dengue patient was 2,798,000 Vietnamese Dong (VND) (US$167.77), 2,154,000 VND for direct costs, and 644,000 VND for indirect costs. There was a 22% difference in cost for those with and without health insurance. In terms of impact on family economies, 47.2% had to borrow money for treatment, and after 6 months, 71.7% had not begun or had only managed part repayments. Approximately 72.9% indicated that the cost of supporting a dengue patient had impacted on the family economy, with the loss averaging 36% of the annual income in the lowest economic quartile.
Plasmodium vivax Pre-Erythrocytic–Stage Antigen Discovery: Exploiting Naturally Acquired Humoral Responses
Authors: Molina Douglas M. , Finney Olivia C. , Arevalo-Herrera Myriam , Herrera Socrates , Felgner Philip L. , Gardner Malcolm J. , Liang Xiaowu , Wang Ruobing
Published: September 2012

The development of pre-erythrocytic Plasmodium vivax vaccines is hindered by the lack of in vitro culture systems or experimental rodent models. To help bypass these roadblocks, we exploited the fact that naturally exposed Fy− individuals who lack the Duffy blood antigen (Fy) receptor are less likely to develop blood-stage infections; therefore, they preferentially develop immune responses to pre-erythrocytic–stage parasites, whereas Fy+ individuals experience both liver- and blood-stage infections and develop immune responses to both pre-erythrocytic and erythrocytic parasites. We screened 60 endemic sera from P. vivax-exposed Fy+ or Fy− donors against a protein microarray containing 91 P. vivax proteins with P. falciparum orthologs that were up-regulated in sporozoites. Antibodies against 10 P. vivax antigens were identified in sera from P. vivax-exposed individuals but not unexposed controls. This technology has promising implications in the discovery of potential vaccine candidates against P. vivax malaria.
Sensitivity of radiative properties of persistent contrails to the ice water path
Authors: De León R. R. , Krämer M. , Lee D. S. , Thelen J. C.
Published: September 2012

Abstract. The dependence of the radiative properties of persistent linear contrails on the variability of their ice water path is assessed in a two-stream radiative transfer model. It is assumed that the ice water content and the effective size of ice crystals in aged contrails do not differ from those observed in natural cirrus; the parameterization of these two variables, based on a correlation with ambient temperature derived from in situ observations, allows a more realistic representation than the common assumption of fixed values for the contrail optical depth and ice crystal effective radius. The results show that the large variability in ice water content that aged contrails may share with natural cirrus, together with an assumed contrail vertical thickness between 220 and 1000 m, translate into a wider range of radiative forcings from linear contrails [1 to 66 m Wm−2] than that reported in previous studies, including IPCC's [3 to 30 m Wm−2]. Further field and modelling studies of the temporal evolution of contrail properties will thus be needed to reduce the uncertainties associated with the values assumed in large scale contrail studies.
The "step feature" of suprathermal ion distributions: a discriminator between acceleration processes?
Authors: Fahr H. J. , Fichtner H.
Published: September 2012

Abstract. The discussion of exactly which process is causing the preferred build-up of v−5-power law tails of the velocity distribution of suprathermal particles in the solar wind is still ongoing. Criteria allowing one to discriminate between the various suggestions that have been made would be useful in order to clarify the physics behind these tails. With this study, we draw the attention to the so-called "step feature" of the velocity distributions and offer a criterion that allows one to distinguish between those scenarios that employ velocity diffusion, i.e. second-order Fermi processes, which are prime candidates in the present debate. With an analytical approximation to the self-consistently obtained velocity diffusion coefficient, we solve the transport equation for suprathermal particles. The numerical simulation reveals that this form of the diffusion coefficient naturally leads to the step feature of the velocity distributions. This finding favours – at least in regions of the appearance of the step feature (i.e. for heliocentric distances up to about 11 AU and at lower energies) – the standard velocity diffusion as a consequence of the particle's interactions with the plasma wave turbulence as opposed to that caused by velocity fluctuation-induced compressions and rarefactions.
An effective depression filling algorithm for DEM-based 2-dimensional surface flow modelling
Authors: Zhu D. , Ren Q. , Xuan Y. , Chen Y. , Cluckie I.
Published: September 2012

Abstract. The surface runoff process in fluvial/pluvial flood modelling is often simulated employing a two-dimensional (2-D) diffusive wave approximation to described by grid based digital elevation models (DEMs). However, a serious problem of this approach may arise when using a 2-D surface flow model which exchanges flows through adjacent cells, or conventional rink removal algorithms which also allow flow to be exchanged along diagonal directions, due to the existence of artificial depression in DEMs. This study firstly analyses the two types of depressions in DEMs and reviews the current depression filling algorithms with a medium sized basin in South-East England, the Upper Medway Catchment (220 km2) used to demonstrate the depression issue in 2-D surface runoff simulation by MIKE SHE with different DEM resolutions (50 m, 100 m and 200 m). An alternative depression-filling algorithm for 2-D overland flow modelling is developed and evaluated by comparing the simulated flows at the outlet of the catchment. This result suggests that the depression estimates at different grid resolution of DEM highly influences overland flow estimation and the new depression filling algorithm is shown to be effective in tackling this issue when comparing simulations in sink-dominated and sink-free digital elevation models, especially for depressions in relatively flat areas on digital land surface models.
Circulation pattern based parameterization of a multiplicative random cascade for disaggregation of daily rainfall under nonstationary climatic conditions
Authors: Lisniak D. , Franke J. , Bernhofer C.
Published: September 2012

Abstract. The use of multiplicative random cascades (MRCs) for temporal rainfall disaggregation has been extensively studied in the past. MRCs are appealing for rainfall disaggregation due to their formal simplicity and the possibility to extract the model parameters directly from observed high resolution rainfall data. These parameters, however, represent the rainfall characteristics of the observation period. Since rainfall characteristics of different time slices are changing due to climate variability, we propose a parameterization approach for MRCs to adjust the parameters according to past (observed) or future (projected) time series. This is done on the basis of circulation patterns (CPs) by extracting a distinct MRC parameterization from high resolution rainfall data, as observed on days governed by each individual CP. The parameterization approach is tested by comparing the statistical properties of disaggregated rainfall time series of two time slices, 1969–1979 and 1989–1999, to the results obtained by two other disaggregation methods (a conceptually similar MRC without CP-based parameterization and a recombination approach) and to the statistical properties of observed hourly rainfall data. In this context, all three approaches use rainfall data of the time slice 1989–1999 for parameterization. We found that the inclusion of CPs into the parameterization of a MRC yields hourly time series that better reproduce the properties of observed rainfall in time slice 1989–1999, as compared to the simple MRC. Despite similar properties of both MRCs for the time slice 1969–1979, we can conclude that the CP-based parameterization approach is applicable for temporal rainfall disaggregation in time slices distinct from the parameterization period. This approach accounts for changes in rainfall characteristics due to changes in the frequency of occurrence of the CPs and allows generating hourly rainfall from daily data, as often provided by a statistical downscaling of global climate change.
Brief communication "Improving the actual coverage of subsampling confidence intervals in atmospheric time series analysis"
Authors: Gluhovsky A. , Nielsen T.
Published: September 2012

Abstract. In atmospheric time series analysis, where only one record is typically available, subsampling (which works under the weakest assumptions among resampling methods), is especially useful. In particular, it yields large-sample confidence intervals of asymptotically correct coverage probability. Atmospheric records, however, are often not long enough, causing a substandard coverage of subsampling confidence intervals. In the paper, the subsampling methodology is extended to become more applicable in such practically important cases.
Numerical models of slab migration in continental collision zones
Authors: Magni V. , van Hunen J. , Funiciello F. , Faccenna C.
Published: September 2012

Abstract. Continental collision is an intrinsic feature of plate tectonics. The closure of an oceanic basin leads to the onset of subduction of buoyant continental material, which slows down and eventually stops the subduction process. In natural cases, evidence of advancing margins has been recognized in continental collision zones such as India-Eurasia and Arabia-Eurasia. We perform a parametric study of the geometrical and rheological influence on subduction dynamics during the subduction of continental lithosphere. In our 2-D numerical models of a free subduction system with temperature and stress-dependent rheology, the trench and the overriding plate move self-consistently as a function of the dynamics of the system (i.e. no external forces are imposed). This setup enables to study how continental subduction influences the trench migration. We found that in all models the slab starts to advance once the continent enters the subduction zone and continues to migrate until few million years after the ultimate slab detachment. Our results support the idea that the advancing mode is favoured and, in part, provided by the intrinsic force balance of continental collision. We suggest that the advance is first induced by the locking of the subduction zone and the subsequent steepening of the slab, and next by the sinking of the deepest oceanic part of the slab, during stretching and break-off of the slab. These processes are responsible for the migration of the subduction zone by triggering small-scale convection cells in the mantle that, in turn, drag the plates. The amount of advance ranges from 40 to 220 km and depends on the dip angle of the slab before the onset of collision.
Caracterización de la vegetación arbórea y arbustiva con potencial de servicios ambientales, al este del lago de Nicaragua
Authors: Salazar Quiroz Estanislao , Gámez Sergio , González N , Siles P.
Published: September 2012

Estudio realizado al Este del Lago de Nicaragua. Para identificar áreas remanentes de bosque, con alto potencial de servicio ambiental. Fueron seleccionados 6 fragmentos de vegetación. Dentro de cada fragmento se identificó la vegetación con menor grado de intervención, y aquí fue establecida una parcela temporal de medición (10,000m2). Fue levantada información de especie y diámetro medido a la altura del pecho (DAP) para todos los individuos con diámetro mayor a 2.5 cm. Las variables estudiadas fueron: Diversidad, uso y manejo del bosque, carbono almacenado. Los índices de diversidad de Simpson y Shannon-Wiener coinciden en que el fragmento 3 es el más diverso presentando 21 familias, 25 géneros y 30 especies. Fue calculado el número de árboles/hectárea, área basal por hectárea y biomasa por hectárea. Las áreas de bosque proporcionan diversos servicios ambientales. Los índices de biodiversidad sugieren, que la mayoría de estos fragmentos albergan una importante diversidad de especies de árboles y arbustos. DOI: http://dx.doi.org/10.5377/nexo.v25i1.782 Nexo Revista Científica,Vol. 25, No. 01, pp.02-08/Junio 2012
El costo de capital y su incidencia en los métodos de flujo de caja descontados
Authors: Medina José R. , Pérez Gustavo A.
Published: September 2012

Un estudio de factibilidad técnico económico en cualquier rama de la ingeniería o en cualquier tipo de negocio, implica conocer una medida de la rentabilidad del emprendimiento. Actualmente, nadie discute que para una toma de decisión fundamentada se deben utilizar los métodos de flujo de caja descontados (DCF), a pesar de que persisten otras formas muy difundidas (por ejemplo: período de repago, relación beneficio/costo). El objetivo del trabajo es analizar críticamente los métodos a utilizar para evaluar proyectos mutuamente excluyentes, como también proponer formas alternativas de análisis de rentabilidad que contemplen la incidencia de las distintas tasas y acoten la decisión de un modo adecuado. La propuesta presentada aquí permite ordenar alternativas excluyentes con criterios que contengan una visión mas completa. El resultado más interesante está relacionado con la sensibilidad de los métodos sobre las variables de decisión inherentes a estos.DOI: http://dx.doi.org/10.5377/nexo.v25i1.793 Nexo Revista Científica,Vol. 25, No. 01, pp.18-21/Junio 2012
Digitalización del entorno a partir de un LIDAR HDL-64E
Authors: Rico Jiménez José de Jesús , González Barbosa José Joel , Hurtado Ramos Juan Bautista , Ornelas Rodríguez Francisco Javier , Hernández García Denis Eduardo , González Barbosa Ricardo
Published: September 2012

En este trabajo se propone un sistema de reconstrucción de mapas para un vehículo autónomo equipado con tecnología LIDAR, capaz de obtener más de un millón de puntos por segundo. Dentro del artículo proponemos la construcción rápida de Mapas Locales (ML) 2D que nos servirán para la navegación local autónoma, y la construcción de Mapas Globales (MG) 2D y 3D que modelizán el ambiente recorrido por el vehículo. Durante el proceso de construcción del Mapa Global se calcula la localización del vehículo con respecto a su posición inicial.DOI: http://dx.doi.org/10.5377/nexo.v25i1.795 Nexo Revista Científica,Vol. 25, No. 01, pp.28-37/Junio 2012
Thermostable and Alkalistable Xylanases Produced by the Thermophilic Bacterium Anoxybacillus flavithermus TWXYL3
Authors: Ellis Joshua T. , Magnuson Timothy S.
Published: September 2012

With the rising cost and finite supply of fossil energy, there is an increasing economic incentive for the development of clean, efficient, and renewable domestic energy. The activities of microorganisms offer the potential conversion of lignocellulosic materials into fermentable sugars, usable for downstream fermentation processes. Strain TWXYL3, a thermophilic facultative anaerobe, was discovered in the Alvord Basin hydrothermal system in Oregon, USA. Phylogenetic analysis of strain TWXYL3 showed it to be 99% similar to the 16S rRNA gene of Anoxybacillus flavithermus WL (FJ950739). A. flavithermus TWXYL3 was shown to secrete a large multisubunit thermostable xylanase complex into the growth medium. Xylanase induction was achieved by resuspending the isolate in a selective xylan-containing medium. Extracellular xylanase activity showed a temperature optimum of 65°C and retained thermostability up to 85°C. Extracellular xylanase activity showed a bimodal pH optimum, with maxima at pH 6 and pH 8. Electrophoretic analysis of the extracellular xylanase shows 5 distinct proteins with xylanase activity. Strain TWXYL3 is the first xylanolytic isolate obtained from the Alvord Basin hydrothermal system and represents a new model system for development of processes where lignocellulosics are converted to biofuel precursors.
A General Gaussian Interest Rate Model Consistent with the Current Term Structure
Authors: Di Francesco Marco
Published: September 2012

We describe an extension of Gaussian interest rate models studied in literature. In our model, the instantaneous spot rate is the sum of several correlated stochastic processes plus a deterministic function. We assume that each of these processes has a Gaussian distribution with time-dependent volatility. The deterministic function is given by an exact fitting to observed term structure. We test the model through various numeric experiments about the goodness of fit to European swaptions prices quoted in the market. We also show some critical issues on calibration of the model to the market data after the credit crisis of 2007.
Listening Skill Requires a Further Look into Second/Foreign Language Learning
Authors: Bozorgian Hossein
Published: September 2012

Current English-as-a-second and foreign-language (ESL/EFL) research has encouraged to treat each communicative macroskill separately due to space constraint, but the interrelationship among these skills (listening, speaking, reading, and writing) is not paid due attention. This study attempts to examine first the existing relationship among the four dominant skills, second the potential impact of reading background on the overall language proficiency, and finally the relationship between listening and overall language proficiency as listening is considered an overlooked/passive skill in the pedagogy of the second/foreign language classroom. However, the literature in language learning has revealed that listening skill has salient importance in both first and second language learning. The purpose of this study is to investigate the role of each of four skills in EFL learning and their existing interrelationships in an EFL setting. The outcome of 701 Iranian applicants undertaking International English Language Testing System (IELTS) in Tehran demonstrates that all communicative macroskills have varied correlations from moderate (reading and writing) to high (listening and reading). The findings also show that the applicants’ reading history assisted them in better performing at high stakes tests, and what is more, listening skill was strongly correlated with the overall language proficiency.
Show Me a Sign
Authors: Wilson Johnnie
Published: September 2012

Observe a first-grade teacher's use of gesture as a mathematics teaching and learning tool in his classroom.
An Appetite for Fractions
Authors: Wilkerson Trena L. , Bryan Tommy , Curry Jane
Published: September 2012

Using candy bars as models gives students a taste for learning to represent fractions whose denominators are factors of twelve.
Pattern-block frenzy
Authors: Anderson Katie L.
Published: September 2012

Teachers share success stories and ideas that stimulate thinking about the effective use of technology in K–grade 6 classrooms. This article describes a set of lessons where sixth graders use virtual pattern blocks to develop proportional reasoning. Students' work with the virtual manipulatives reveals a variety of creative solutions and promotes active engagement. The author suggests that technology is most effective when coupled with worthwhile mathematical tasks and rich classroom discussions.
The king's really big bowl
Authors: Seshaiyer Padmanabhan , Freeman Patricia W.
Published: September 2012

Each article includes the prompt used to initiate the discussion, a portion of dialogue, student work samples (when applicable) and teacher insights into the mathematical thinking of the students. This month, students are taught the importance of ensuring that their solutions are reasonable. This article describes the creative thinking of a group of students trying to rationalize their unreasonable answer when they meet the Mango problem.
Dosimetric Characteristics of Aqueous Solutions of Sandalfix Red Dye for Gamma Dosimetry
Authors: Taqmeem Hussain  , Muhammad Shahbaz  , Inam-ul-Haq  , Hashim Farooq  , Nasir Amin  , Yasir Jamil
Published: September 2012

Gamma dosimetric behavior of the aqueous solutions of the Sandalfix Red (C.I. Reactive Red 195A) dye was studied. The sample solutions of two chemical natures i.e., Acidic and Alkaline; were irradiated by Co60 ?-source in the range 0-100kGy. The "Control samples" were kept un-irradiated and also chemically neutral. The dosimetry was done in three phases i.e., Low, Intermediate and High, ranging from 100-1000Gy, 1-10kGy and 10-100kGy respectively. The found values of the "λmax" and the molar extinction coefficient "ε" of the dye were 565nm and 0.19×104 dm3 mol-1cm-1 respectively. The absorbance (A) of the aqueous solutions was studied at the absorption band maxima (λmax). It was hence found that the aqueous solutions of the Sandalfix Red C4BLN dye were able to be used as passive dosimeters in the range 10-100 kGy i.e., the sample solutions have shown radioactive exponential behavior of response in the "Intermediate and High dosimetry". However, a linear response was shown by the sample solutions in the "Low dosimetry".
Effect of Pesticide Residues on Health and Different Enzyme Levels in the Milk of Women from Karachi-Pakistan
Authors: Uzma Mehboob  , Mohammad Ahmed Azmi  , Mohammad Arshad Azmi  , Syed Naeem ul Hasan Naqvi
Published: September 2012

The aim of this study was to investigate the presence of pesticide residues in human milk and their effects on the enzyme levels (cholinesterase and lactate dehydrogenase) as well as the health status of the pesticide exposed women. Total 135 milk samples from 45 women were collected from nine different divisions of Karachi, Pakistan. In addition ten milk samples were also collected from normal subjects. The milk samples were taken at day 1, day 15 and day 30 from the same women and from the same divisions. The data indicated that only cypermethrin, deltamethrin, malathion and match were identified. The highest concentration 34.86 µg/10 µl of deltamethrin and the lowest concentration 0.336 µg/10 µl of cypermethrin was found in the milk sample. It may be concluded that exposed women showed significant increased and decreased enzyme levels at different division and also complained about the disturbance in the normal functioning of different organ system and possibly produced various ailments and clinically suffered with skin diseases, backache, disturbance in micturition, difficulty in breathing, asthma and hepatitis.
La rébellion de 1837 et les modèles théoriques de l’émergence de la nation et du nationalisme
Authors: Bellavance Marcel
Published: September 2012

Cet article propose une interprétation de la rébellion de 1837 à la lumière du grand courant libéral et nationalitaire européen. En s'inspirant des modèles théoriques de l'émergence de l'État-nation et du nationalisme, l'auteur essaiera en effet de dégager une typologie applicable à l'expérience canadienne. Il se demande si, ce qui a été présenté jusqu'ici comme singulier dans l'historiographie, ne relèverait pas plutôt de l'universel.
La censure en temps de guerre : Radio-Canada et le plébiscite de 1942
Authors: Canuel Alain
Published: September 2012

RÉSUMÉ

La présente étude se propose d'analyser, dans le contexte de la censure pendant la Deuxième Guerre mondiale, la controverse que soulève la Société Radio-Canada (SRC) lors de la campagne du plébiscite de 1942 en permettant aux tenants du OUI de se faire entendre et en refusant aux tenants du NON de présenter leur point de vue sur les ondes nationales. En plus d'exacerber les tenants du NON, cette décision mine la crédibilité de la SRC qui devient rapidement identifiée à l'appareil répressif de l'État. L'analyse remet également en question l'affirmation selon laquelle la prise de décision de la SRC lors du plébiscite aurait eu pour effet de favoriser le développement du réseau français au Canada.
Parenté et stratification sociale dans une paroisse rurale de la vallée du Saint-Laurent au milieu du XIXe siècle1
Authors: Dessureault Christian
Published: September 2012

Les réseaux et les rapports de parenté représentent des vecteurs importants des recherches sur la société rurale du Québec. Cependant, nous n’avons encore aucune étude qui évalue de manière systématique l’importance des liens de parenté dans une paroisse rurale à un moment spécifique de l’histoire. Nous ne connaissons pas, de manière précise, la densité des liens familiaux entre les divers ménages d’une même paroisse, ni surtout le degré de variabilité de ces liens de parenté selon les familles, selon le genre et selon les groupes sociaux.Cette recherche vise à présenter une première mesure concernant l’étendue et les types des liens de parenté entre tous les chefs de ménage d’une vieille paroisse rurale de la vallée du Saint-Laurent en 1861: Saint-Antoine–de-Lavaltrie. L’un des principaux objectifs de cet article est de vérifier l’étendue, la sélectivité sociale et la différenciation selon le genre des réseaux de parenté dans un territoire donné où se vivent, au quotidien, les relations sociales. Cet article aide à mieux circonscrire le poids différencié des rapports de parenté dans les divers groupes au sein des communautés rurales. Cette recherche permet aussi de corroborer ou de nuancer, dans un contexte historique précis, certains constats de la sociologie, de l’anthropologie et de l’histoire sociale concernant l’importance et la structure des réseaux de parenté.
Le voyage de Radisson et Des Groseilliers au lac Supérieur, 1659-1660 : un événement marquant dans la consolidation des relations franco-amérindiennes
Authors: Fournier Martin
Published: September 2012

Les récits de voyage de Radisson, redécouverts dans les archives anglaises et publiés pour la première fois en 1885, contiennent un grand nombre d'informations précises et sou- vent exclusives sur les premières relations diplomatiques et commerciales que nouèrent les Européens et les Amérindiens, dans la seconde moitié du XVIIe siècle. Des recherches récentes mettent en évidence l'expertise de Radisson sur cette question et réhabilitent l'essentiel de son témoignage, qui avait été plutôt négligé jusqu'ici par les historiens. Cet article présente la stratégie que déployèrent Radisson et Des Groseilliers lors du voyage pion- nier qu'ils accomplirent ensemble au lac Supérieur, en 1659-1660 (quatrième récit de voyage de Radisson) et donne un aperçu des conclusions riches et nuancées qu'il est possible de tirer du témoignage de cet acteur et témoin privilégié, concernant les relations non missionnaires que développèrent les Français et leurs partenaires amérindiens après la dispersion des Hurons et la fin du monopole jésuite en territoire autochtone, en 1650.
L’histoire urbaine au Québec : la recherche récente à la maîtrise et au doctorat
Authors: Guérard François
Published: September 2012

L’auteur cherche à dégager les grandes orientations qui ont marqué le champ de l’histoire urbaine au Québec depuis une décennie, à travers une recension critique des mémoires de maîtrise et des thèses de doctorat. Quelles perspectives ont été privilégiées ? Discerne-t-on quelque renouveau ? Il apparaît, dans l’ensemble, que nombre de travaux d’étudiants ont largement contribué à approfondir nos connaissances sur l’urbain au Québec. Toutefois, on peut souhaiter un raffermissement des pratiques interdisciplinaires qui tirerait exemple de l’heureux mariage de la géographie et de l’histoire, ainsi que l’ajout d’études qui embrasseraient des territoires et des périodes d’enquête plus vastes.
Ville et santé au Québec un bilan de la recherche historique
Authors: Guérard François
Published: September 2012

La santé en milieu urbain au Québec n'est devenue objet d'étude pour les historiens qu'à partir de la décennie 1970. Depuis, divers chercheurs qui inscrivaient leur démarche dans le courant de l'histoire sociale ont réexaminé, du point de vue de la santé, la ville et sa population, ses institutions et ses services. Dans quelles perspectives les ont-ils abordés? Comment les ont-ils intégrés à leurs problématiques? Quelle a été leur contribution à la compréhension de la société québécoise? Un bilan historiographique est présenté qui cherche à répondre à ces questions, tout en mettant en perspective les acquis de recherche et les avenues encore négligées.
Entente cordiale? La section montréalaise du fonds patriotique canadien, 1914-1923 le bénévolat de guerre à Montréal
Authors: Morton Desmond
Published: September 2012

L'histoire de la guerre se concentre sur les soldats. Mais qu'arrive-t-il à ceux et celles qu'ils laissent derrière ? Dès le début de la guerre, en 1914, les Montréalais ont reconnu le fardeau des familles des réservistes faiblement rémunérés, français, belges et britanniques et, par la suite, celui des familles de leurs propres soldats canadiens. Le Fonds patriotique montréalais a hérité d'une vieille tradition charitable. Ses leaders, tels Herbert Ames, Helen Reid et Raoul Dandurand, en ont fait à la fois la principale source de financement et un modèle pour les organisations similaires à travers le Canada. L'organisation interne de la section montréalaise du Fonds patriotique a aussi reflété les relations changeantes entre les élites anglophones et francophones de la ville, le développement du professionnalisme dans le travail social et les limites du volontarisme pour absorber les coûts de la guerre. Les trois campagnes de souscription de la section montréalaise fournissent un instantané surprenant des relations entre francophones et anglophones à trois différents moments de la guerre.