50 research outputs found
Advances in mapping ice-free surfaces within the Northern Antarctic peninsula region using polarimetric RADARSAT-2 data
Ice-free areas within the Northern Antarctic Peninsula
region are of interest for studying changes occurring to
surface covers, including those related to glacial coverage,
raised beach deposits and periglacial processes and
permafrost. The objective of this work is to map the main
surface covers within ice-free areas of King George Island,
the largest island of the South Shetlands archipelago, using
fully polarimetric RADARSAT-2 SAR data.
Surface covers such as rock outcrops and glacial till, stone
fields, patterned ground, and sand and gravel deposits form
the most representative classes and account for 84 km2 of
the ice-free areas on the island. A distribution of complex
geomorphological features and landforms was obtained,
being some of them considered indicators of periglacial
processes and presence of permafrost.Published versio
Improving Student Dentist Competencies and Perception of Difficulty in Delivering Care to Children with Developmental Disabilities Using a Virtual Patient Module
An interactive, multimedia, virtual patient module was designed and developed on compact disc (CD-ROM) to address the need for student dentists to increase their competence and decrease their perception of difficulty in caring for children with developmental disabilities. A development team consisting of pediatric dentistry faculty members, parents of children with developmental disabilities, an individual with a developmental disability, and educational specialists developed an interactive virtual patient case. The case involved a ten-year-old child with Down syndrome presenting with a painful tooth. Student dentists were required to make decisions regarding proper interactions with the child, as well as appropriate clinical procedures throughout the case. Differences in perceived difficulty level and knowledge change were measured, as well as the student dentists\u27 overall satisfaction with the learning experience. Significant results were obtained in both perceived difficulty level and knowledge-based measures for student dentists. Participants reported overall satisfaction with the modules. Preparing student dentists to provide sensitive and competent care for children with developmental disabilities is a critical need within dentistry. This study demonstrated that an interactive, multimedia (CD-ROM), virtual patient learning module for student dentists is potentially an effective tool in meeting this need
Soil characteristics on varying lithological substrates in the South Shetland Islands, maritime Antarctica
The final version is available at:
http://www.sciencedirect.com/science/journal/00167061Soils in ice-free areas of Livingston Island have been forming since the last deglaciation in a maritime warmer climate that is more humid than in interior Antarctica. A soil survey was carried out on Byers and Hurd peninsulas to characterize the soils and investigate the processes. Soils were sampled on two different substrates, mudstones and volcanic rocks in Byers Peninsula and greywackes in Hurd Peninsula. Sampling sites were located on raised beaches, platforms, and on volcanic outcrops across an altitudinal range from few m to 150 m a.s.l.. The pH, electrical conductivity, carbonates and organic matter showed similar patterns in each geomorphic unit but their values differed between bedrocks. The sand, silt and clay contents differed greatly in the soils on mudstones and volcanic rocks. The elemental composition was closely related to mineralogy of parent materials. Mg, K, Zn, Mn, and Fe were similar in the soils on all bedrocks. The Al content was highest on the volcanic rocks. The largest difference in the Ca content was between the soils on greywackes and mudstones. The Na, Pb, and Ba contents in soils on the mudstones differed greatly from the rest of bedrocks. Geochemical and mineralogical characteristics suggest that the main process involved in soil development was the mechanical disintegration of bedrock although there was also some leaching. Cryogenic processes play a key role in soil development but chemical weathering processes were also involved in soil evolution although limited in extent due to the restriction of water circulation to summer.This work is a contribution to the project REN2005-03256 of the DGICYT, Spanish Ministry of Science and Technology.Peer reviewe
Harmonização de dados geológicos à escala 1:1M de dois países vizinhos
RESUMO: Este trabalho pretende divulgar as ações desenvolvidas no âmbito da harmonização de dados geológicos pelos Serviços Geológicos de Espanha e Portugal, respetivamente, IGME (Instituto Geológico y Mineiro de España) e LNEG (Laboratório Nacional de Energia e Geologia, I.P.). Nesta fase do projeto, que teve início em Abril de 2017, dá-se especial atenção à forma como as duas instituições se organizaram com vista a atingir o objetivo final: A disponibilização de serviços de mapas OGC INSPIRE compliant. O ponto de partida foi a publicação do novo Mapa Geológico de Espanha e Portugal à escala 1:1M, em 2015. As duas instituições têm implementado num SIG, em software ArcGIS, a informação de referência deste mapa: os mapas geológicos de cada país, à escala 1:1 000 000. A partir deles o trabalho de harmonização INSPIRE
dos dados foi efetuado em paralelo com abordagens e tecnologias distintas. Por um lado o LNEG adotou a Geodatabase template INSPIRE incluída no ArcGis for INSPIRE, como modelo de dados, não tendo utilizado nenhuma ferramenta Extract Transform Load (ETL) no processo de harmonização de dados. Esta base de dados foi implementada em SQL Server e os serviços de dados criados com o ArcGIS Server e ArcGIS for INSPIRE. O IGME optou pela implementação do esquema UML INSPIRE numa base de dados espacial em SQL Server e publicou os serviços WMS e WFS com recurso ao Tomcat Apache server e Geoserver. Para realizar a transformação dos dados foram utilizadas principalmente duas ferramentas em função da complexidade das transformações em causa: o FME e o HALE. O principal desafio deste projeto foi o de estabelecer uma metodologia de trabalho que permitisse a integração e harmonização, numa única Base de Dados, de toda a informação de Espanha e de Portugal e a posterior criação e validação dos serviços WMS e WFS, para disponibilização nos GeoPortais institucionais e para reportar à INSPIRE. Adicionalmente foi interessante avaliar os resultados obtidos a partir das diferentes abordagens tecnológicas utilizadas. Outras questões abordadas neste projeto são: a definição da área de trabalho (Continente e Ilhas mais o Offshore); os idiomas (Espanhol, Português e Inglês); e o sistema de referência de coordenadas adotado (EPSG 4258) devido à inclusão das ilhas portuguesas (Açores e Madeira).info:eu-repo/semantics/publishedVersio
Echo-character mapping of the Galician Continental Margin and the adjacent abyssal plains
La cartografía y análisis de las facies acústicas que se determinan a partir de la interpretación y correlación de los perfiles sísmicos de muy alta resolución, es una herramienta muy útil para la caracterización de los procesos sedimentarios recientes y su distribución en ambientes marinos profundos. Este trabajo presenta el primer mapa de ecocarácter del Margen Continental de Galicia y las llanuras abisales adyacentes. El mapa se realizó sobre la base del análisis e interpretación de los datos de batimetría y reflectividad de las ecosondas multihaz SIMRAD EM12, EM120 y EM1002, y los perfiles sísmicos de muy alta resolución de la ecosonda paramétrica SIMRAD TOPAS PS18. Sobre la base de la morfología del fondo marino, la reflectividad y los caracteres del eco acústico, se identificaron 26 tipos de ecos en la secuencia sedimentaria más superficial.
Estos tipos de eco se han clasificado en cuatro grupos principales: bien definidos, irregulares, hiperbólicos y ondulados. Esta información ha sido adquirida en el marco del ‘Programa de Investigación Científica de la Zona Económica Exclusiva Española’, coordinado por el Ministerio de Defensa, durante las campañas oceanográficas que se han realizado a bordo del BIO Hespérides del 2001 a 2003 y del 2006 a 2009.The acoustic facies mapping and analyses from the interpretation and correlation of very high resolution seis-
mic profiles, is a very useful tool for the characterization of the recent sedimentary processes and their distribution in the deep-sea environments. This work presents the first echo-character map of the Galicia Continental Margin and the adjacent abyssal plains. The map was carried out on the basis of the analysis and interpretation of the bathymetry and reflectivity data from the SIMRAD EM12, EM120 and EM1002 multibeam echosounders, and the high resolution seismic profiles from the SIMRAD TOPAS PS18 parametric echosounder. Based on the seafloor morphology, backscatter and acoustic echo-characters, 26 echo types were identified in the uppermost sedimentary sequence. These echo-types have been classified into four main groups: Distinct, Irregular, Hyperbolic and Undulated echoes. This information has been acquired in the framework of the ‘Scientific Research Program of the Economic Exclusive Zone of Spain’, which is coordinated by the Defense Ministry, during the oceanographic cruises carried out on board of the R/V Hesperides in 2001 to 2003 and 2006 to 2009.Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEMinisterio de Ciencia e Innovación (MICINN)Instituto Geológico y Minero de Españapu
Geomorphological and sedimentary processes of the glacially influenced northwestern Iberian continental margin and abyssal plains
The offshore region of northwestern Iberia offers an opportunity to study the impacts of along-slope processes on the morphology of a glacially influenced continental margin, which has traditionally been conceptually characterised by predominant down-slope sedimentary processes. High-resolution multibeam bathymetry, acoustic backscatter and ultrahigh-resolution seismic reflection profile data are integrated and analysed to describe
the present-day and recent geomorphological features and to interpret their associated sedimentary processes.
Seventeen large-scale seafloor morphologies and sixteen individual echo types, interpreted as structural features (escarpments, marginal platforms and related fluid escape structures) and depositional and erosional bedforms developed either by the influence of bottom currents (moats, abraded surfaces, sediment waves, contourite drifts and ridges) or by gravitational features (gullies, canyons, slides, channel-levee complexes and submarine fans), are identified for the first time in the study area (spanning ~90,000 km2 and water depths of 300m to 5 km). Different types of slope failures and turbidity currents are mainly observed on the upper and lower slopes and along submarine canyons and deep-sea channels. The middle slope morphologies are mostly determined by the actions of bottom currents (North Atlantic Central Water, Mediterranean Outflow Water, Labrador Sea Water and North Atlantic Deep Water), which thereby define the margin morphologies and favour the reworking and deposition of sediments. The abyssal plains (Biscay and Iberian) are characterised by pelagic deposits and channel-lobe systems (the Cantabrian and Charcot), although several contourite features are also
observed at the foot of the slope due to the influence of the deepest water masses (i.e., the North Atlantic Deep Water and Lower Deep Water). Thiswork shows that the study area is the result of Mesozoic to present-day tectonics (e.g. themarginal platforms and structural highs). Therefore, tectonism constitutes a long-term controlling factor, whereas the climate, sediment supply and bottom currents play key roles in the recent short-term architecture and dynamics. Moreover, the recent predominant along-slope sedimentary processes observed in the studied northwestern Iberian Margin represent snapshots of the progressive stages and mixed deep-water system developments of the marginal platforms on passive margins and may provide information for a predictive model of the evolution of other similar margins.Departamento de Investigación y Prospectiva Geocientífica, Unidad de Tres Cantos, Instituto Geológico y Minero de España, EspañaDepartamento de Geología y Geoquímica, Universidad Autónoma de Madrid, EspañaDepartment of Earth Sciences, Royal Holloway University of London, Reino Unid
Soil characteristics on varying lithological substrates in the South Shetland Islands, maritime Antarctica
The final version is available at:
http://www.sciencedirect.com/science/journal/00167061Soils in ice-free areas of Livingston Island have been forming since the last deglaciation in a maritime warmer climate that is more humid than in interior Antarctica. A soil survey was carried out on Byers and Hurd peninsulas to characterize the soils and investigate the processes. Soils were sampled on two different substrates, mudstones and volcanic rocks in Byers Peninsula and greywackes in Hurd Peninsula. Sampling sites were located on raised beaches, platforms, and on volcanic outcrops across an altitudinal range from few m to 150 m a.s.l.. The pH, electrical conductivity, carbonates and organic matter showed similar patterns in each geomorphic unit but their values differed between bedrocks. The sand, silt and clay contents differed greatly in the soils on mudstones and volcanic rocks. The elemental composition was closely related to mineralogy of parent materials. Mg, K, Zn, Mn, and Fe were similar in the soils on all bedrocks. The Al content was highest on the volcanic rocks. The largest difference in the Ca content was between the soils on greywackes and mudstones. The Na, Pb, and Ba contents in soils on the mudstones differed greatly from the rest of bedrocks. Geochemical and mineralogical characteristics suggest that the main process involved in soil development was the mechanical disintegration of bedrock although there was also some leaching. Cryogenic processes play a key role in soil development but chemical weathering processes were also involved in soil evolution although limited in extent due to the restriction of water circulation to summer.This work is a contribution to the project REN2005-03256 of the DGICYT, Spanish Ministry of Science and Technology.Peer reviewe
Geomorphology and surface landforms distribution in selected ice-free areas in the South Shetland Islands, Northern Antarctic Peninsula region
Ice-free areas cover a small percentage of the land in the South Shetland Islands. However, they are significant as they contain ecosystems highly sensitive to environmental changes and are located within a region affected by global warming. These areas are dominated by periglacial, glacial, fluvial, and coastal processes and landforms, where permafrost is often present. Soil development is observed although vegetation cover is sparse and closely related to the geomorphology. The mapping and monitoring of ice-free areas is important as they are highly sensitive to climate change. The objective of this study was to characterize and map surface landforms in ice-free areas using traditional mapping methods as well as advanced remote sensing techniques. Geomorphological and topographical maps were initially obtained through field measurements and observations, and complemented with existing aerial photography at scales between 1:2000 and 1:25000. Thereafter, satellite-borne data became available and were included in the methodology to further determine the distribution of the landforms. In the Antarctic environment, Synthetic Aperture Radar (SAR) provides the most reliable images as data can be obtained in any weather conditions as well as during the day and night. Fully polarimetric SAR RADARSAT-2 were used to determine seven different terrain classes representing surface landforms in ice-free areas around Maxwell Bay (King George Island). The SAR remote sensing techniques were successfully applied to identify different periglacial, fluvial, glacial, coastal, as well as lithological landforms. Field data from Fildes Peninsula were used to train a supervised classifier to map further areas around Maxwell Bay. In this case, the ice-free areas around Maxwell Bay clearly show the dominance of periglacial landforms and processes. Therefore, these techniques can be used to compare past and future results and to monitor areas affected by changing environmental factors and increasing human activitiesDepartamento de Geología y Geoquímica, Universidad Autónoma de Madrid, EspañaDepartamento de Medio Ambiente, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, EspañaDepartamento de Geografía, Universidad de Valladolid, EspañaInstituto Geológico y Minero de España, EspañaComputer Vision and Remote Sensing Group, Technische Universität Berlin, Alemani