244 research outputs found
A Landsat-based analysis of tropical forest dynamics in the Central Ecuadorian Amazon : Patterns and causes of deforestation and reforestation
Tropical deforestation constitutes a major threat to the Amazon rainforest. Monitoring forest dynamics is therefore necessary for sustainable management of forest resources in this region. However, cloudiness results in scarce good quality satellite observations, and is therefore a major challenge for monitoring deforestation and for detecting subtle processes such as reforestation. Furthermore, varying human pressure highlights the importance of understanding the underlying forces behind these processes at multiple scales but also from an interand transdisciplinary perspective. Against this background, this study analyzes and recommends different methodologies for accomplishing these goals, exemplifying their use with Landsat timeseries and socioeconomic data. The study cases were located in the Central Ecuadorian Amazon (CEA), an area characterized by different deforestation and reforestation processes and socioeconomic and landscape settings. Three objectives guided this research. First, processing and timeseries analysis algorithms for forest dynamics monitoring in areas with limited Landsat data were evaluated, using an innovative approach based in genetic algorithms. Second, a methodology based in image compositing, multisensor data fusion and postclassification change detection is proposed to address the limitations observed in forest dynamics monitoring with timeseries analysis algorithms. Third, the evaluation of the underlying driving forces of deforestation and reforestation in the CEA are conducted using a novel modelling technique called geographically weight ridge regression for improving processing and analysis of socioeconomic data. The methodology for forest dynamics monitoring demonstrates that despite abundant data gaps in the Landsat archive for the CEA, historical patterns of deforestation and reforestation can still be reported biennially with overall accuracies above 70%. Furthermore, the improved methodology for analyzing underlying driving forces of forest dynamics identified local drivers and specific socioeconomic settings that improved the explanations for the high deforestation and reforestation rates in the CEA. The results indicate that the proposed methodologies are an alternative for monitoring and analyzing forest dynamics, particularly in areas where data scarcity and landscape complexity require approaches that are more specialized.Landsat-basierte Analyse der Dynamik tropischer Wälder im Zentral-Ecuadorianischen Amazonasgebiet: Muster und Ursachen von Abholzung und Wiederaufforstung Die tropische Entwaldung stellt eine große Bedrohung für den AmazonasRegenwald dar. Daher ist die Überwachung von Walddynamiken eine notwendige Maßnahme, um eine nachhaltige Bewirtschaftung der Waldressourcen in dieser Region zu gewährleisten. Jedoch verschlechtert Bewölkung die Qualität der Satellitenaufnahmen und stellt die hauptsächliche Herausforderung für die Überwachung der Entwaldung sowie die Detektierung einhergehender Prozesse, wie der Wiederaufforstung, dar. Darüber hinaus zeigt der unterschiedliche menschliche Nutzungsdruck, wie wichtig es ist, die zugrundeliegenden Kräfte hinter diesen Prozessen auf mehreren Ebenen, aber auch interund transdisziplinär, zu verstehen. Variierender anthropogener Einfluss unterstreicht die Notwendigkeit, unterschwellige Prozesse (oder "Driver") auf multiplen Skalen aus interund transdisziplinärer Sicht zu verstehen. Darauf basierend analysiert und empfiehlt die vorliegende Studie unterschiedliche Methoden, welche unter Verwendung von LandsatZeitreihen und sozioökonomischen Daten zur Erreichung dieser Ziele beitragen. Die Untersuchungsgebiete befinden sich im ZentralEcuadorianischen Amazonasgebiet (CEA). Einem Gebiet, das einerseits durch differenzierte Entwaldungsund Aufforstungsprozesse, andererseits durch seine sozioökonomischen und landschaftlichen Gegebenheiten geprägt ist. Das Forschungsprojekt hat drei Zielvorgaben. Erstens werden auf genetischen Algorithmen basierten Verfahren zur Verarbeitung der Zeitreihenanalyse für die Überwachung der Walddynamik in Gebieten, für die nur begrenzte LandsatDaten vorhanden waren, bewertet. Zweitens soll eine Methode in Anlehnung an Satellitenbildkompositen, Datenfusion von mehreren Satellitenbildern und Veränderungsdetektion gefunden werden, die Einschränkungen der Walddynamik durch Entwaldung mithilfe von ZeitreihenAlgorithmen thematisiert. Drittens werden die Ursachen der Entwaldung/Abholzung im CEA anhand der geographischen gewichteten RidgeRegression, die zur einen verbesserten Analyse der sozioökonomischen Information beiträgt, bewertet. Die Methodik für das WalddynamikMonitoring zeigt, dass trotz umfangreicher Datenlücken im LandsatArchiv für das CEA alle zwei Jahre die historischen Entwaldungsund Wiederaufforstungsmuster mit einer Genauigkeit von über 70% gemeldet werden können. Eine verbesserte Analysemethode trägt außerdem dazu bei, die für die Walddynamik verantwortlichen treibenden Kräfte zu identifizieren, sowie lokale Treiber und spezifische sozioökonomische Rahmenbedingungen auszumachen, die eine bessere Erklärung für die hohen Entwaldungsund Wiederaufforstungsraten im CEA aufzeigen. Die erzielten Ergebnisse machen deutlich, dass die vorgeschlagenen Methoden eine Alternative zum Monitoring und zur Analyse der Walddynamik darstellen; Insbesondere in Gebieten, in denen Datenknappheit und Landschaftskomplexität spezialisierte Ansätze erforderlich machen
Lateral Dynamics of Flexible Rotors Supported by Controllable Gas Bearings Theory & Experiment
Active lubrication applied to radial gas journal bearings. Part 2: Modelling improvement and experimental validation
The Bender Gradual Scoring System for Assessment of People with Intellectual Disabilities
O Bender-Sistema de Pontuação Gradual (B-SPG) é um dos principais sistemas de avaliação visomotora utilizados no Brasil. Entretanto, estudos com amostras com desenvolvimento atípico são escassos. Este estudo verificou o funcionamento dos itens do B-SPG em uma amostra com desenvolvimento típico (Grupo A, n = 198, idade entre sete e dez anos, aplicação coletiva) e com pessoas com diferentes diagnósticos de deficiência intelectual (Grupo B, n = 203, idade entre 11 e 30 anos, aplicação individual) respeitando-se todos os aspectos éticos. Os resultados indicaram figuras com funcionamento diferencial. A figura 6 favoreceu o grupo A, e as figuras 1 e 2 favoreceram o B. A curva de informação do teste indicou baixa precisão nas pontuações extremas. Discute-se a realização de mais estudos, visando melhor compreensão do funcionamento do B-SPG em diferentes amostras de modo a testar o quanto os achados se generalizam a outras amostras.El Bender-Sistema de Puntuación Gradual (B-SPG) es uno de los principales sistemas de evaluación visomotora utilizados en Brasil. Sin embargo, los estudios con muestras con desarrollo atípico todavía son escasos. Este estudio verificó el funcionamiento de los ítems del B-SPG en una muestra de personas con desarrollo típico (Grupo A; n = 198; edades entre 7 y 10 años, aplicación colectiva) y con personas con diferentes diagnósticos de deficiencia intelectual (Grupo B; n = 203; edades entre 11 y 30 años, aplicación individual), respetando todos los aspectos éticos. Los resultados indicaron figuras con funcionamiento diferencial. La figura 6 favoreció al grupo A, mientras que las figuras 1 y 2 al Grupo B. La curva de información del test indicó una baja precisión en las puntuaciones extremas. Se debate la realización de más estudios que pretendan una mejor comprensión del funcionamiento del B-SPG en diferentes muestras, para comprobar si los resultados obtenidos en esta ocasión , se generalizan en otras muestras.The Bender Gradual Scoring System (B-GSS) is one of the main systems of visual-motor assessment used in Brazil. Studies, however, seldom address samples with atypical development. This study tested the psychometric properties of the B-GSS items in a sample of individuals with typical development (Group A; n = 198; aged between seven and 10 years old; group application) and in a sample with intellectual disabilities (Group B; n = 203; aged between 11 and 30 years old; individual application), in accordance with ethical recommendations. The results reveal figures with differential functioning. Figure 6 was biased toward group A, while figures 1 and 2 were biased toward group B. Test of the information curve indicates low precision for extreme scores. There is a need for further research to better understand how the B-GSS items work across different samples in order to verify whether such findings can be generalized to other samples
Immigration and pension system in Portugal
Comunicação apresentada no VI Annual Meeting of REDGOB – Migration, Social Cohesion and Governability, em Lisboa, em Dezembro de 2008.The Portuguese Pension System is submitted to two risks. Over the period 2005-2050, a decrease
of workforce and an increase of old-age persons are eminent, which provide for the doubling of the
dependency rate. As a result the system is not financially sustainable in the medium and long terms
and it is expected that the system will enter in a growing deficit in 2015, when expenditures will
overcome its revenues. Hence, the system is subject to a demographic risk (associated with the
reduction of the fertility rates, the augmentation of the life expectancy and the increase of the
dependency rate) and to a financial insolvency risk (motivated by the lack of equatorial
correspondence of expenditures and revenues).
Immigration could be a solution to the unsustainability of Pension Systems. This paper examines
the role of immigration on resolving these two risks. We investigate, based on the European
Economy (2006) projections about the impact of ageing on the public expenditure for the period
2005-50, the required immigrant flows that maintain the old-age dependency rate observed in 2004
and we calculate also the number of immigrants required to promote a null result for the
Portuguese Pension System.
We conclude that the number of immigrants that guarantees a null financial result is much lower
than one that eliminates the demographic risk. Still, compared with forecasts of the European
Economy (2006), these figures are substantially higher and show an upward trend during the
period under review, therefore, contrary to the expected trend announced by that European entity.
(JEL: H55, J11, J26
Estudio del mortero de revestimiento de un estanque de una mansion patrimonial de fines del siglo XIX
En este trabajo se evalúa un mortero de revestimiento correspondiente al estanque de la mansión Sans Souci de la ciudad de Tandil de la provincia de Buenos Aires. Las técnicas de estudio empleadas fueron un análisis químico para determinar particularmente el contenido de Calcio (CaO) y de Sílice (SiO2), compuestos presentes en ligantes cálcicos o cementíceos. Complementariamente se realizaron observaciones bajo lupa binocular y microscopio sobre muestra cruda y molida respectivamente.
Del análisis óptico con lupa binocular y microscopio óptico de polarización, se determina que para la confección del mortero se han utilizado materiales finos de calidades físicas y estáticas óptimas, se identificaron cristales de cuarzo monomineral, cuarzo policristalino y esporádicamente, cristales fibrosos de wollastonita, piroxenos y microcristales de carbonatos. De los resultados y observaciones realizados se concluye que el mortero presenta un alto contenido de SiO2 atribuido a un proceso de silificación, antigua técnica empleada para otorgar una mayor compacidad y dureza superficial, incrementando de esta manera su impermeabilidad
Quaerite et Invenietis: Tras el Rastro «Queer» en la Edad Media
In this article, I distance myself from the chrono-normativity of time frameworks traditionally deployed to understand and analyze history. Instead, I inquire into the jagged lines of history. My focus lies specifically on the medieval period, and I seek to queer traditional interpretations of this era by posing indecent and uncomfortable questions. This inquiry can potentially bring medievalist work out of the theo(ideo)logical closet. My ultimate goal is to unveil a more diverse and nuanced understanding of the past, considering the full range of human experience while un/covering different answers: quaerite et invenietis [Seek and ye shall find]
Urban-Rural Gradients Predict Educational Gaps : evidence from a Machine Learning Approach Involving Academic Performance and Impervious Surfaces in Ecuador
Ajuts: This research was funded by the Indoamerica University Research Program (grant number: INV-0010-004)Academic performance (AP) is explained by a multitude of factors, principally by those related to socioeconomic, cultural, and educational environments. However, AP is less understood from a spatial perspective. The aim of this study was to investigate a methodology using a machine learning approach to determine which answers from a questionnaire-based survey were relevant for explaining the high AP of secondary school students across urban-rural gradients in Ecuador. We used high school locations to construct individual datasets and stratify them according to the AP scores. Using the Boruta algorithm and backward elimination, we identified the best predictors, classified them using random forest, and mapped the AP classification probabilities. We summarized these results as frequent answers observed for each natural region in Ecuador and used their probability outputs to formulate hypotheses with respect to the urban-rural gradient derived from annual maps of impervious surfaces. Our approach resulted in a cartographic analysis of AP probabilities with overall accuracies around 0.83-0.84% and Kappa values of 0.65-0.67%. High AP was primarily related to answers regarding the academic environment and cognitive skills. These identified answers varied depending on the region, which allowed for different interpretations of the driving factors of AP in Ecuador. A rural-to-urban transition ranging 8-17 years was found to be the timespan correlated with achievement of high AP
Conserva de anchoveta en aceite de sacha inchi
Alamar es un enlatado de anchoveta en aceite extraído de las semillas del sacha inchi, producido en la planta piloto del Instituto Tecnológico Pesquero, perteneciente al Ministerio de la Producción, lo que asegurará que nuestro producto sea llamado a brindar un alimento rico en nutrientes y delicioso al paladar.
En la primera parte del presente trabajo hacemos una revisión de la industria pesquera y agrícola del Perú para luego centrarnos en nuestros productos estrella. Seguidamente procedemos a desarrollar algunas herramientas primero para contextualizar como el análisis de las 5 fuerzas de Porter; luego usamos el lienzo Canvas para plasmar nuestra idea de negocio.
Finalmente, definimos las estrategias operacionales y de marketing para luego terminar con un análisis financiero de inversiones y rentabilidad
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