Method for landslides detection with semi-automatic procedures: The case in the zone center-east of Cauca department, Colombia

Landslides are a common natural hazard that causes human casualties, but also infrastructure damage and land-use degradation. Therefore, a quantitative assessment of their presence is required by means of detecting and recognizing the potentially unstable areas. This research aims to develop a method supported on semiautomatic methods to detect potential mass movements at a regional scale. Five techniques were studied: Morphometry, SAR interferometry (InSAR), Persistent Scatterer InSAR (PS-InSAR), SAR polarimetry (PolSAR) and NDVI composites of Landsat 5, Landsat 7, and Landsat 8. The case study was chosen within the mid-eastern area of the Cauca state, which is characterised by its mountainous terrain and the presence of slope instabilities, officially registered in the CGS-SIMMA landslide inventory. This inventory revealed that the type `slide' occurred with 77.4% from the entire registries, `fall' with 16.5%, followed by `creeps' with 3%, flows with 2.6%, and `lateral spread' with 0.43%. As a result, we obtained the morphometric variables: slope, CONVI, TWI, landform, which were highly associated with landslides. The effect of a DEM in the processing flow of the InSAR method was similar for the InSAR coherence variable using the DEMs ASTER, PALSAR RTC, Topo-map, and SRTM. Then, a multiInSAR analysis gave displacement velocities in the LOS direction between -10 and 10 mm/year. With the dual-PolSAR analysis (Sentinel-1), VH and VV C-band polarised radar energy emitted median values of backscatters, for landslides, about of -14.5 dB for VH polarisation and -8.5 dB for VV polarisation. Also, L-band fully polarimetric NASA-UAVSAR data allowed to nd the mechanism of dispersion of CGS landslide inventory: 39% for surface scattering, 46.4% for volume dispersion, and 14.6% for double-bounce scattering. The optical remote sensing provided NDVI composites derived from Landsat series between 2012 and 2016, showing that NDVI values between 0.40 and 0.70 had a high correlation to landslides. In summary, we found the highest categories related to landslides by Weight of Evidence method (WofE) for each spaceborne technique applied. Finally, these results were merged to generate the landslide detection model by using the supervised machine learning method of Random Forest. By taking training and test samples, the precision of the detection model was of about 70% for the rotational and translational types.Los deslizamientos son una amenaza natural que causa pérdidas humanas, daños a la infraestructura y degradación del suelo. Una evaluación cuantitativa de su presencia se requiere mediante la detección y el reconocimiento de potenciales áreas inestables. Esta investigación tuvo como alcance desarrollar un método soportado en métodos semi-automáticos para detectar potenciales movimientos en masa a escala regional. Cinco técnicas fueron estudiadas: Morfometría, Interferometría radar, Interferometría con Persistent Scatterers, Polarimetría radar y composiciones del NDVI con los satélites Landsat 5, Landsat 7 y Landsat 8. El caso de estudio se seleccionó dentro de la región intermedia al este del departamento del Cauca, la cual se caracteriza por terreno montañoso y la presencia de inestabilidades de la pendiente oficialmente registrados en el servicio SIMMA del Servicio Geológico Colombiano. Este inventario reveló que el tipo de movimiento deslizamiento ocurrió con una frecuencia relativa de 77.4%, caidos con el 16.5% de los casos y reptaciones con 3%, flujos con 2.6% y propagación lateral con 0.43%. Como resultado, se obtuvo las variables morfométricas: pendiente, convergencia, índice topográfico de humedad y forma del terreno altamente asociados con los deslizamientos. El efecto de un DEM en el procesamiento del método InSAR fue similar para la variable coherencia usando los DEMs: ASTER, PAlSAR RTC, Topo-map y SRTM. Un análisis Multi-InSAR estimó velocidades de desplazamiento en dirección de vista del radar entre -10 y 10 mm/año. El análisis de polarimetría dual del Sentinel-1 arrojó valores de retrodispersión promedio de -14.5 dB en la banda VH y -8.5dB en la banda VV. Las cuatro polarimetrías del sensor aéreo UAVSAR permitió caracterizar el mecanismo de dispersión del Inventario de Deslizamiento así: 39% en el mecanismo de superficie, 46.4% en el mecanismo de volumen y 14.6% en el mecanismo de doble rebote. La información generada en el rango óptico permitió obtener composiciones de NDVI derivados de la plataforma Landsat entre los años 2012 y 2016, mostrando que el rango entre 0.4 y 0.7 tuvieron una alta asociación con los deslizamientos. En esta investigación se determinaron las categorías de las variables de Teledetección más altamente relacionadas con los movimientos en masa mediante el método de Pesos de Evidencias (WofE). Finalmente, estos resultados se fusionaron para generar el modelo de detección de deslizamientos usando el método supervisado de aprendizaje de máquina Random Forest. Tomando muestras aleatorias para entrenar y validar el modelo en una proporción 70:30, el modelo de detección, especialmente los movimientos de tipo rotacional y traslacional fueron clasificados con una tasa general de éxito del 70%.Ministerio de CienciasConvocatoria 647 de 2014Research line: Geotechnics and Geoenvironmental HazardDoctorad

Organization of the Petroleum Exporting Countries (OPEC) and Opportunities for Sustainable Development

OPEC is in the business of natural resources which inherently connects them to the concept of sustainable development. The main focus of this research is to answer the following question: Does OPEC have the power to implement measures consistent with the concept of sustainable development? During the course of this research, the paper Sustainable Development and OPEC, by Herman E. Daly, was uncovered. Daly proposes a sink tax to be implemented by OPEC. This would act as a global fiduciary which would, in theory, bring the consumption level of oil down to a more sustainable level by raising the price and lowering the demand. The research in this paper finds that Dalys speculative idea, while interesting, is unrealistic; the idea is not feasible given OPECs stated goals. In addition, there are ethical considerations concerning a conflict of interest on a global and local scale

Measurement of CH3_3D on Titan at Submillimeter Wavelengths

We present the first radio/submillimeter detection of monodeuterated methane (CH$_3$D) in Titan's atmosphere, using archival data from of the Atacama Large Millimeter/submillimeter Array (ALMA). The $J_K=2_1-1_1$ and $J_K=2_0-1_0$ transitions at 465.235 and 465.250 GHz ($\sim0.644$ mm) were measured at significance levels of $4.6\sigma$ and $5.7\sigma$, respectively. These two lines were modeled using the Non-linear optimal Estimator for MultivariatE spectral analySIS (NEMESIS) radiative transfer code to determine the disk-averaged CH$_3$D volume mixing ratio = $6.157\times10^{-6}$ in Titan's stratosphere (at altitudes $\gt130$ km). By comparison with the CH$_4$ vertical abundance profile measured by Cassini-Huygens mass spectrometry, the resulting value for D/H in CH$_4$ is $(1.033\pm0.081)\times10^{-4}$. This is consistent with previous ground-based and in-situ measurements from the Cassini-Huygens mission, though slightly lower than the average of the previous values. Additional CH$_3$D observations at higher spatial resolution will be required to determine a value truly comparable with the Cassini-Huygens CH$_4$ measurements, by measuring CH$_3$D with ALMA close to Titan's equator. In the post-Cassini era, spatially resolved observations of CH$_3$D with ALMA will enable the latitudinal distribution of methane to be determined, making this an important molecule for further studies.Comment: 9 pages, 4 figure

Estrategias para la Conservación y Uso Sustentable de la Diversidad Biológica

Research is intended to develop strategies for the conservation and sustainable use of biodiversity in the National Agricultural School of Technology (ETAN) "Don Simon Rodriguez", of the Municipality Pedraza del Estado Barinas. It is characterized by being a qualitative study in the field of action research and supported in a field design. The stage was the National Agricultural School of Technology “Don Simon Rodriguez”, the key informants are composed of (2) teachers and (1) a worker of the institution. The technique used was the interview in depth, the instrument used was a guide to establishing the thematic units. Regarding the treatment of the results, the information obtained from the reports of the immersed persons in the investigative process was categorized, contrasted and theorized, a diagnosis was carried out on the management of the woodland areas of the institution. Subsequently, the proposal called Action plan for the conservation and sustainable use of biological diversity was developed. Similarly, the preconceived plan was developed where participants considered that the executed actions allowed the acquisition of primary knowledge of biodiversity and the sustainable use of natural resources.Está investigación tuvo como propósito desarrollar estrategias para la conservación y uso sustentable de la diversidad biológica en la Escuela Técnica Agropecuaria Nacional (ETAN) “Don Simón Rodríguez”, del Municipio Pedraza del Estado Barinas. Se caracteriza por ser un estudio cualitativo en la modalidad de investigación acción y sustentado en un diseño de campo. El escenario fue la Escuela Técnica Agropecuaria Nacional “Don Simón Rodríguez”, los informantes claves están constituidos por (2) docentes y (1) obrero de la institución. La técnica utilizada fue la entrevista en profundidad, el instrumento utilizado fue un guión para establecer las unidades temáticas. Con respecto al tratamiento de los resultados se categorizó, contrastó y teorizó la información obtenida de los relatos de las personas inmersas en el proceso investigativo, se elaboró un diagnóstico sobre el manejo de las áreas boscosas de la institución. Posteriormente se elaboró la propuesta denominada Plan de acción para la conservación y uso sustentable de la diversidad biológica. Asimismo, se desarrolló el plan preconcebido en donde los participantes consideraron que las acciones ejecutadas permitieron adquirir conocimientos primordiales sobre la biodiversidad y el uso sustentable de los recursos naturales

Método para la caracterización de las formas del terreno en zonas de montaña utilizando Modelos Digitales de Elevación. Caso: Departamento del Cauca

Se desarrolló un método para diferenciar, delimitar, caracterizar y representar cartográfiamente las formas del terreno en zonas de montaña. Se evaluaron los DEMs SRTM de resoluciones espaciales aproximadas de 31 m y 92 m, y el DEM-ASTER de 31 m de resolución, éste último en el área de estudio mostró datos locales erróneos por lo que el análisis de exactitud vertical con enfoque geoestadístico, comparación con curvas de nivel a 1:25000 y 1:10000 y puntos de control GPS indicó que el DEM-SRTM de 31 m, era el que mejor cumplía la tolerancia máxima de exactitud vertical. Se analizaron criterios y metodologías con sus algoritmos para extraer automáticamente las formas del terreno, desde la obtención de elementos básicos del terreno, el análisis del elemento en el contexto paisajístico, superposición de parámetros mediante álgebra de mapas y clasificación no supervisada mediante agrupación k-means; algunos implementados en software propietario y otros en software libre. Se calcularon parámetros del terreno locales y regionales, y se analizaron sus distribuciones de manera univariada y multivariada, ésta última permitió seleccionar un conjunto de ellos con la menor redundancia para implementar un método de clasificación no supervisada. La clasificación no supervisada implementada en una zona centro oriental del departamento del Cauca, Colombia, permitió encontrar 12 clases de formas del terreno a partir de parámetros como el índice de convergencia, el índice topográfico de humedad, la profundidad de los valles, la insolación solar y la elevación misma, con un coeficiente de similaridad kappa máxima de 39%, valor bajo pero con un potencial alto para continuar con investigaciones adicionales, de acuerdo con resultados cualitativos encontrados al compararlos con el globo virtual Googleearth y con la leyenda geomorfológica del mapa de suelos oficial para el área de estudio.Abstract.A method was developed to differentiate, define, characterize and represent cartográfiamente landforms in mountain areas. SRTM DEMs were evaluated for approximate spatial resolution of 31 m and 92 m, and the ASTER DEM-31 m resolution, the latter in the study area showed erroneous local data so the vertical accuracy analysis geostatistical approach, compared with contours at 1:25000 and 1:10000 and GPS control points indicated that the DEM-SRTM 31 m, was best served the maximum vertical accuracy tolerance. Criteria and methodologies were analyzed with algorithms to automatically extract landforms, from obtaining basic elements of the terrain, the analysis of the element in the landscape context, overlapping parameters using map algebra and unsupervised classification using k-means clustering and some implemented in proprietary software and other free software. Parameters were calculated from the local and regional area, and their distributions were analyzed as univariate and multivariate latter allowed to select a set of them with less redundancy to implement a method of unsupervised classification. The unsupervised classification implemented in eastern central area of Cauca, Colombia, allowed to find 12 kinds of landforms based on parameters such as the rate of convergence, the topographic wetness index, the depth of the valleys, solar insolation and the same elevation, with a kappa coefficient of similarity of 39% maximum, low value but with a high potential for additional investigations continue, according to qualitative results found when compared to the virtual globe with GoogleEarth and geomorphological map legend official soil survey area.Maestrí

The longitudinal conductance of mesoscopic Hall samples with arbitrary disorder and periodic modulations

We use the Kubo-Landauer formalism to compute the longitudinal (two-terminal) conductance of a two dimensional electron system placed in a strong perpendicular magnetic field, and subjected to periodic modulations and/or disorder potentials. The scattering problem is recast as a set of inhomogeneous, coupled linear equations, allowing us to find the transmission probabilities from a finite-size system computation; the results are exact for non-interacting electrons. Our method fully accounts for the effects of the disorder and the periodic modulation, irrespective of their relative strength, as long as Landau level mixing is negligible. In particular, we focus on the interplay between the effects of the periodic modulation and those of the disorder. This appears to be the relevant regime to understand recent experiments [S. Melinte {\em et al}, Phys. Rev. Lett. {\bf 92}, 036802 (2004)], and our numerical results are in qualitative agreement with these experimental results. The numerical techniques we develop can be generalized straightforwardly to many-terminal geometries, as well as other multi-channel scattering problems.Comment: 13 pages, 11 figure

A cross sectional pilot study utilising STrain Analysis and Mapping of the Plantar Surface (STAMPS) to measure plantar load characteristics within a healthy population

BackgroundNo in-shoe systems, measuring both components of plantar load (plantar pressure and shear stress) are available for use in patients with diabetes. The STAMPS (STrain Analysis and Mapping of the Plantar Surface) system utilises digital image correlation (DIC) to determine the strain sustained by a deformable insole, providing a more complete understanding of plantar shear load at the foot-surface interface.Research questionsWhat is the normal range and pattern of strain at the foot-surface interface within a healthy population as measured by the STAMPS system? Is STAMPS a valid tool to measure the effects of plantar load?MethodsA cross-sectional study of healthy participants was undertaken. Healthy adults without foot pathology or diabetes were included. Participants walked 20 steps with the STAMPS insole in a standardised shoe. Participants also walked 10 m with the Novel Pedar® plantar pressure measurement insole within the standardised shoe. Both measurements were repeated three times. Outcomes of interest were global and regional values for peak resultant strain (SMAG) and peak plantar pressure (PPP).ResultsIn 18 participants, median peak SMAG and PPP were 35.01 % and 410.6kPa respectively. The regions of the hallux and heel sustained the highest SMAG (29.31 % (IQR 24.56–31.39) and 20.50 % (IQR 15.59–24.12) respectively) and PPP (344.8kPa (IQR 268.3 – 452.5) and 279.3kPa (IQR 231.3–302.1) respectively). SMAG was moderately correlated with PPP (r= 0.65, p < 0.001). Peak SMAG was located at the hallux in 55.6 % of participants, at the 1st metatarsal head (MTH) in 16.7 %, the heel in 16.7 %, toes 3–5 in 11.1 % and the MTH2 in 5.6 %.SignificanceThe results demonstrate the STAMPS system is a valid tool to measure plantar strain. Further studies are required to investigate the effects of elevated strain and the relationship with diabetic foot ulcer formation

The Potential of Remote Sensing to Assess Conditioning Factors for Landslide Detection at a Regional Scale: The Case in Southeastern Colombia

This landslide detection research applied remote sensing techniques. Morphometry to derive both DEM terrain parameters and land use variables. SAR interferometry (InSAR) for showing that InSAR coherence and InSAR displacement obtained with SRTM DEM 30 m resolution were strongly related to landslides. InSAR coherence values from 0.43 to 0.66 had a high association with landslides. PS-InSAR allowed to estimate terrain velocities in the satellite line-of-sight (LOS) in the range − 10 to 10 mm/year concerning extremely slow landslide displacement rates. SAR polarimetry (PolSAR) was used over L-band UAVSAR quad-pol data, obtaining the scattering mechanism of volume and surface retrodispersion more associated with landslides. The optical remote sensing with a multitemporal approach for change detection by multi-year Landsat (5, 7 and 8)-NDVI, showed that NDVI related to landslides had values between 0.42 and 0.72. All the information was combined into a multidimensional grid product and crossed with training data containing a Colombian Geologic Service (CGS) landslide inventory. A detection model was implemented using the Random Forest supervised method relating the training sample of landslides with multidimensional explanatory variables. A test sample with a proportion of 70:30 allowed to find the accuracy of detection of about 70.8% for slides type

Titan Science with the James Webb Space Telescope (JWST)

The James Webb Space Telescope (JWST), scheduled for launch in 2018, is the successor to the Hubble Space Telescope (HST) but with a significantly larger aperture (6.5 m) and advanced instrumentation focusing on infrared science (0.6-28.0 $\mu$m ). In this paper we examine the potential for scientific investigation of Titan using JWST, primarily with three of the four instruments: NIRSpec, NIRCam and MIRI, noting that science with NIRISS will be complementary. Five core scientific themes are identified: (i) surface (ii) tropospheric clouds (iii) tropospheric gases (iv) stratospheric composition and (v) stratospheric hazes. We discuss each theme in depth, including the scientific purpose, capabilities and limitations of the instrument suite, and suggested observing schemes. We pay particular attention to saturation, which is a problem for all three instruments, but may be alleviated for NIRCam through use of selecting small sub-arrays of the detectors - sufficient to encompass Titan, but with significantly faster read-out times. We find that JWST has very significant potential for advancing Titan science, with a spectral resolution exceeding the Cassini instrument suite at near-infrared wavelengths, and a spatial resolution exceeding HST at the same wavelengths. In particular, JWST will be valuable for time-domain monitoring of Titan, given a five to ten year expected lifetime for the observatory, for example monitoring the seasonal appearance of clouds. JWST observations in the post-Cassini period will complement those of other large facilities such as HST, ALMA, SOFIA and next-generation ground-based telescopes (TMT, GMT, EELT).Comment: 50 pages, including 22 figures and 2 table