2,421 research outputs found
Testing for Unit Roots: Mexico's GDP
The study presents an analysis of the stochastic nature of the gross domestic product of Mexico for the period 1900-2001. Several specifications to test for the existence of unit roots are presented. The conventional tests, Dickey Fuller, Augmented Dickey Fuller and Phillips Perron, indicate that the series is nonstationary and integrated of order 1. The result is robust to the inclusion of exogenously and endogenously determined structural breaks. Interestingly, when structural breaks are determined endogenously, a structural break in 1907 is identified. We interpret this results as suggesting that setting the date of a structural break ex-ante might not be the most efficient procedure when testing for unit roots.Unit Root tests, structural Break and gross domestic product of Mexico.
Determination and Analysis of Residual Stresses Induced by High Speed Milling Using a Micro-indent Method
The purpose of this work is to determine and analyze residual stress normal components and anisotropy degrees introduced by high-speed milling in specimens of AA 6082-T6 and AA 7075-T6 aluminum alloys. At each machined sample, the climb and conventional cutting zones were evaluated and compared. This paper includes a comprehensive study of thermal and mechanical effects associated with the residual stress introduction. For normal components determination, an optimized micro-indent method was used. Each measurement sequence from this approach was performed using a high accuracy measuring machine and classified according to thermal deviations measured. The residual displacements were determined with an absolute error down to ±300 nm. The normal components analysis allowed to infer the strong influence of the rolling process previous to high-speed milling and besides, the stress levels associated with thermal effects (higher in AA 7075-T6). Finally, the lower residual stress anisotropy degrees in both materials observed in the conventional cutting zone would indicate more homogenous local plastic stretching in this region for all planar directions.Fil: Vottero, S.. Universidad Tecnológica Nacional. Facultad Regional Rafaela; ArgentinaFil: Diaz, Felipe Victor. Universidad Tecnológica Nacional. Facultad Regional Rafaela; ArgentinaFil: Mammana, Claudio Alejandro. Universidad Tecnológica Nacional. Facultad Regional Rafaela; ArgentinaFil: Guidobono, A.. Instituto Nacional de Tecnología Industrial; Argentin
Synchronization of the Mexican and the U.S. Economies: The Case of the Manufacturing Sector. Sincronización entre las economías de México y Estados Unidos: el caso del Sector Manufacturero.
Es elevada la dependencia entre la industria maquiladora de exportación de México y el desempeño de la economía de Estados Unidos; sin embargo, son relativamente escasas las investigaciones que dan cuenta del comportamiento de otras industrias y su relación con el mercado del país septentrional. Los autores realizan un análisis comparativo entre los mercados laborales de las industrias manufactureras de ambos países. The study is centered on the synchronization between the economies of Mexico and the United States with special reference to the manufacturing sector. The authors examine the dependency between the assembly plant industry for export in Mexico and the performance of the economy of the United States. The authors also make a comparative analysis between the labor markets of the manufacturing industries in both countries.Mexico, United States, Labor Markets, manufacturing
Can quality-attribute requirements be identified from early aspects? : QAMiner: a preliminary approach to quality-attribute mining
Specifying good software requirement documents is a difficult task. Many software projects fail because of the omission or bad encapsulation of concerns. A practical way to solve these problems is to use advanced separation of concern techniques, such as aspect-orientation. However, quality attributes are not completely addressed by them. In this work, we present a novel approach to uncover quality-attribute requirements. The identification is performed in an automated-fashion, relying on early asp ects to guide it and using ontologies to model domain knowledge. Our tool was evaluated on two well-known systems, and contrasted with architectural documents.Sociedad Argentina de Informática e Investigación Operativ
Audiovisual translation: Subtitling and revoicing
This chapter explores audiovisual translation (AVT) from a didactic perspective, with special emphasis on subtitling and revoicing. After a historical overview of AVT training, a detailed discussion ensues on how the technological advances and changes that have taken place in the creation, localization, and distribution of audiovisual productions have triggered the emergence of new professional practices and research avenues. In recent years, the proliferation of audiovisual and multimedia content has led to the diversification of translatable assets, and training in subtitling and revoicing has become an integral part of the translation curriculum offered in most educational centres. Yet, the teaching methodologies currently used in AVT courses are sometimes out of date, mainly relying on theoretical translation premises and trends rather than on current professional practices and state of the art technology. We take stock of the most recurrent AVT pedagogical methods, extricate some of the reasons behind this state of affairs and, following a competences-based approach, put forward a series of experience- and research-based recommendations for the design and implementation of AVT training in higher education
Kinetic Monte Carlo applied to the electrochemical study of the Li-ion graphite system
To delve deeper into the kinetics involved in the staging phenomena of lithium insertion into graphite, it is necessary to develop theoretical models that emulate the physical phenomenon involved. In the present work kinetic Monte Carlo simulations are used to carry out a thorough analysis of the Li-ion graphite system, with the twofold aim of providing atomistic support for interpretations based on several experimental electrochemical techniques commonly used in the laboratory and of making theoretical predictions for future experimental work. Cyclic voltammograms and chronoamperometric transients are obtained, and diffusion coefficients and exchange current densities are calculated at different Li loadings of graphite. These results are compared with selected experimental data from the literature. In this way, there emerge details that cannot be observed in ordinary experiments due to methodological/instrumental limitations. For example, it is found that chronoamperometric responses are different for intercalation and deintercalation, the latter being a faster process. The reason why these phenomena are different is revealed, supporting and widening experimental assumptions. The present results also suggest that the intrinsic hysteresis observed in experimental work (and in simulations) is due to kinetic factors.Fil: Gavilán Arriazu, Edgardo Maximiliano. Universidad Nacional de Santiago del Estero. Instituto de Bionanotecnología del Noa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Bionanotecnología del Noa; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Teórica y Computacional; ArgentinaFil: Pinto, Oscar Alejandro. Universidad Nacional de Santiago del Estero. Instituto de Bionanotecnología del Noa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Bionanotecnología del Noa; ArgentinaFil: López de Mishima, Beatriz A.. Universidad Nacional de Santiago del Estero. Instituto de Bionanotecnología del Noa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Bionanotecnología del Noa; ArgentinaFil: Barraco Diaz, Daniel Eugenio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Oviedo, Oscar Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Leiva, Ezequiel Pedro M.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentin
Expansion of the agricultural frontier in the largest South American Dry Forest: Identifying priority conservation areas for snakes before everything is lost
Conservation planning relies on integrating existing knowledge, social-environmental contexts, and potential threats to identify gaps and opportunities for action. Here we present a case study on how priority areas for conservation can be determined using existing information on biodiversity occurrence and threats. Specifically, our goals are: (1) to model the ecological niche of twelve endemic snake species in the Dry Chaco Forest, (2) to quantify the impact of the deforestation rates on their distributions, (3) to propose high priority areas for conservation in order to improve the actual protected area system, and (4) to evaluate the influence of the human footprint on the optimization of selected priority areas. Our results demonstrate that Argentinian Dry Chaco represent, on average, ~74% of the distribution of endemic snake species and deforestation has reduced suitable areas of all snake species in the region. Further, the current protected areas are likely insufficient to conserve these species as only very low percentages (3.27%) of snakes’ ranges occur within existing protected areas. Our models identified high priority areas in the north of the Chaco forest where continuous, well-conserved forest still exists. These high priority areas include transition zones within the foothill forest and areas that could connect patches of forest between the western and eastern Chaco forest. Our findings identify spatial priorities that minimize conflicts with human activities, a key issue for this biodiversity hotspot area. We argue that consultation with stakeholders and decision-makers are urgently needed in order to take concrete actions to protect the habitat, or we risk losing the best conservation opportunities to protect endemic snakes that inhabit the Argentinian Dry Chaco.Fil: Andrade Díaz, Soledad María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del Noroeste Argentino. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto de Bio y Geociencias del Noroeste Argentino; ArgentinaFil: Sarquis, Juan Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Loiselle, Bette A.. University of Florida; Estados UnidosFil: Giraudo, Alejandro Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina. University of Florida; Estados Unidos. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias; ArgentinaFil: Diaz Gomez, Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del Noroeste Argentino. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto de Bio y Geociencias del Noroeste Argentino; Argentin
Scale of Goals of Study for University Students
Actualmente disponemos de gran cantidad de trabajos que muestran la implicación de las metas de
estudio en la motivación por estudiar y aprender. Este trabajo analiza la motivación académica y, especialmente,
la variable “metas de estudio”. El principal propósito de esta investigación es conocer las
características psicométricas de la adaptación de la Escala de Metas de Estudio a la población universitaria
chilena. Los participantes son 542 estudiantes chilenos, de distintas facultades universitarias. Los resultados
del análisis factorial y de consistencia interna son aceptables en las tres subescalas. Estos resultados
fundamentan el uso de la Escala de Metas de Estudio para evaluar la motivación al estudio de
alumnas y alumnos universitarios en Chile (CL).At the present time we have great amount of works that show the implication of the goals of study in the
motivation to study and to learn. In this paper the academic motivation and, specially, the variable
“goals of study” is assess. The principal aim of the present research is know the Questionnaire to
Measure Achievement Goal Tendency’s psicometric characteristics with 542 Chilean university students
of different faculties. Results of the factor analysis and the internal consistency are acceptable in three
subscales. In conclusion, these results support the use of the Questionnaire to Measure Achievement
Goal Tendencies to assess the study motivation in university students in Chile (CL).(undefined
BeCAPTCHA-Type: Biometric Keystroke Data Generation for Improved Bot Detection
This work proposes a data driven learning model for the synthesis of
keystroke biometric data. The proposed method is compared with two statistical
approaches based on Universal and User-dependent models. These approaches are
validated on the bot detection task, using the keystroke synthetic data to
improve the training process of keystroke-based bot detection systems. Our
experimental framework considers a dataset with 136 million keystroke events
from 168 thousand subjects. We have analyzed the performance of the three
synthesis approaches through qualitative and quantitative experiments.
Different bot detectors are considered based on several supervised classifiers
(Support Vector Machine, Random Forest, Gaussian Naive Bayes and a Long
Short-Term Memory network) and a learning framework including human and
synthetic samples. The experiments demonstrate the realism of the synthetic
samples. The classification results suggest that in scenarios with large
labeled data, these synthetic samples can be detected with high accuracy.
However, in few-shot learning scenarios it represents an important challenge.
Furthermore, these results show the great potential of the presented models.Comment: Paper accepted in IEEE Computer Society Workshop on Biometrics
(CVPRw) 202
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