4D-SFM photogrammetry for monitoring sediment dynamics in a debris-flow catchment: Software testing and results comparison

In recent years, the combination of Structure-from-Motion (SfM) algorithms and UAV-based aerial images has revolutionised 3D topographic surveys for natural environment monitoring, offering low-cost, fast and high quality data acquisition and processing. A continuous monitoring of the morphological changes through multi-temporal (4D) SfM surveys allows, e.g., to analyse the torrent dynamic also in complex topography environment like debris-flow catchments, provided that appropriate tools and procedures are employed in the data processing steps. In this work we test two different software packages (3DF Zephyr Aerial and Agisoft Photoscan) on a dataset composed of both UAV and terrestrial images acquired on a debris-flow reach (Moscardo torrent - North-eastern Italian Alps). Unlike other papers in the literature, we evaluate the results not only on the raw point clouds generated by the Structure-from- Motion and Multi-View Stereo algorithms, but also on the Digital Terrain Models (DTMs) created after post-processing. Outcomes show differences between the DTMs that can be considered irrelevant for the geomorphological phenomena under analysis. This study confirms that SfM photogrammetry can be a valuable tool for monitoring sediment dynamics, but accurate point cloud post-processing is required to reliably localize geomorphological changes

Mapping potential surface ponding in agriculture using UAV-SfM

Among the environmental problems that could affect agriculture, one of the most critical is ponding. This may be defined as water storage on the surface in concavities and depressions due to soil saturation. Stagnant water can seriously affect crops and the management of agricultural landscapes. It is mainly caused by prolonged rainfall events, soil type, or wrong mechanization practices, which cause soil compaction. To better understand this problem and thus provide adequate solutions to reduce the related risk, high-resolution topographic information could be strategically important because it offers an accurate representation of the surface morphology. In the last decades, new remote sensing techniques provide interesting opportunities to understand the processes on the Earth's surface based on geomorphic signatures. Among these, Uncrewed Aerial Vehicles (UAVs), combined with the structure-from-motion (SfM) photogrammetry technique, represent a solid, low-cost, rapid, and flexible solution for geomorphological analysis. This study aims to present a new approach to detect the potential areas exposed to water stagnation at the farm scale. The high-resolution digital elevation model (DEM) from UAV-SfM data is used to do this. The potential water depth was calculated in the DEM using the relative elevation attribute algorithm. The detection of more pronounced concavities and convexities allowed an estimation and mapping of the potential ponding conditions. The results were assessed by observations and field measurements and are promising, showing a Cohen's k(X) accuracy of 0.683 for the planimetric extent of the ponding phenomena and a Pearson's rxy coefficient of 0.971 for the estimation of pond water depth. The proposed workflow provides a useful indication to stakeholders for better agricultural management in lowland landscapes

Heroic viticulture: Environmental and socioeconomic challenges of unique heritage landscapes

Steep-slope agricultural landscapes cover a small fraction of global agricultural areas.1 Despite the limited coverage, they are relevant for high-quality food and wine production, history, and landscape value. On steep slopes, centuries of effort and tradition have created a unique cultural heritage to be preserved. Here, peculiar traditional local knowledge of soil and water conservation combined with agronomic practices (e.g., dry-stone wall terracing) has been handed down for generations. However, such landscapes are fragile and under threat

Biofilm bucal asociado al tratamiento ortodóncico y riesgo de caries: Caracterización clínica y microbiológica de pacientes previos al tratamiento

El uso de dispositivos de ortodoncia pone a los pacientes en condición de vulnerabilidad, por lo que valorar el riesgo individual constituye una importante actividad previa al inicio del tratamiento. El objetivo de este trabajo fue evaluar las condiciones clínicas, sialoquímicas y microbiológicas de los pacientes al inicio del tratamiento ortodóncico, para adecuar la motivación de estos pacientes y las acciones clínicas que eviten patologías secundarias. Se trabajó con 15 pacientes adultos con necesidad de tratamiento ortodóncico, se confeccionó la historia clínica, se registraron parámetros clínicos y se tomaron muestras de placa bacteriana y saliva para determinar parámetros microbiológicos y sialoquímicos. Los pacientes mostraron altos valores medios del índice de caries; el 80% presentó valores del índice de placa indicativos de mala higiene bucal. Los pacientes más jóvenes mostraron mayor cantidad de placa bacteriana y cantidades de S.mutans significativamente mayor en los sectores anterior y posterior de la boca (p=0,05 y 0,006, respectivamente). Se observaron menores recuentos de microorganismos en la zona anterior de la boca que en la posterior, con diferencias significativas en S.mutans y Candida (p<0,0001). No se aisló Candida en la zona anterior de la boca; en la zona posterior se aisló Candida (35% de los pacientes) con mayores valores en varones que en mujeres (p=0,05). Este estudio muestra la necesidad de motivación del paciente por parte del ortodoncista previo al tratamiento ortodóncico con el fin de prevenir lesiones de descalcificación del esmalte dentario frecuentemente observadas al finalizar los tratamientos ortodóncicos.Fil: Vera Cucchiaro, Verónica. Universidad Nacional de Córdoba. Facultad de Odontología; Argentina

INVESTIGATING THE PERFORMANCE OF A HANDHELD MOBILE MAPPING SYSTEM IN DIFFERENT OUTDOOR SCENARIOS

In recent years, portable Mobile Mapping Systems (MMSs) are emerging as valuable survey instruments for fast and efficient mapping of both internal and external environments. The aim of this work is to assess the performance of a commercial handheld MMS, Gexcel HERON Lite, in two different outdoor applications. The first is the mapping of a large building, which represents a standard use-case scenario of this technology. Through the second case study, that consists in the survey of a torrent reach, we investigate instead the applicability of the handheld MMS for natural environment monitoring, a field in which portable systems are not yet widely employed. Quantitative and qualitative assessment is presented, comparing the point clouds obtained from the HERON Lite system against reference models provided by traditional techniques (i.e., Terrestrial Laser Scanning and Photogrammetry)

Ultrasound imaging of the sciatic nerve division in the popliteal fossa: A volunteer study

Background and Objectives: A sciatic nerve block at the level of the popliteal fossa is frequently administered for post-operative analgesia for surgery below the knee. While ultrasound continues to gain popularity as the technique of choice for guiding needle positioning during peripheral nerve blocks, practitioners can begin to utilize ultrasound to look for patterns of anatomical significance. Recognizing anatomical variations among different demographic populations can help practitioners improve in performing nerve blocks. We aim to determine if predictable variability exists in sciatic nerve bifurcation location and depth at the level of the popliteal fossa. Methods: After IRB approval, eligible subjects were screened for ASA I or II status and demographic data was collected. Fifty subjects were enrolled. The SonoSite MicroMaxx® with 38-mm broadband linear array, 13-6 MHz probe with color Doppler and image capturing capabilities was used for ultrasound measurements. With subject lying prone, the location of the sciatic nerve in relation to the popliteal crease and skin-to-nerve distance were assessed via ultrasound. Two independent investigators confirmed nerve location for measurements. Analyses were performed with SAS version 9.1 using Pearson Correlation Coefficients and regression analysis. Results: Gender stratification revealed that, while males were both taller and heavier, skin-nerve measurements for depth were consistently deeper in females (p-value 0.02). Independent of the right or left leg, male gender and increased height decreases the skin-nerve distance, while increased weight increases the distance. There was no correlation between patient characteristics and crease-nerve distance. In some subjects, variability of crease-nerve distance even existed between their right and left leg. Conclusion: We show that significant variability exists for actual sciatic nerve bifurcation location, or target injection site, with consistently deeper skin depth values for female patients when compared to male patients, accounting for height and weight. These findings suggest visualization techniques such as ultrasound may lead to better localization of ideal injection sites

Analyzing topographic changes through LiDAR and SfM techniques: assessing the deposition-erosion patterns and estimation of debris-flow volume in the eastern Italian Alps

On 4 August 2015, a very high intensity storm, 31.5 mm in 20 min (94.5 mm/h), hit the massif of Mount Antelao on the Venetian Dolomites (eastern Italian Alps) triggering stony debris flow characterized by high magnitude. It routed along the Ru Secco Creek and progressively reached the resort area and the village of San Vito di Cadore, causing fatalities and damages. The aim of the present research is the study of this debris-flow event by means of pre and post-event topographic data derived by LiDAR (Light Detection and Ranging) and Structure-from-Motion (SfM) photogrammetry technique associated to its occurrence. This study analyzes the Digital Terrain Models (DTMs) derived from LiDAR survey carried out in July 2015 and UAV-SfM data obtained in September 2019. The most important step to compare these multi-temporal surveys was the co-registration process, fundamental to guarantee the coherence among the two different surveys. The post-event SfM-DTM of the area routed by debris flow subtracted to the pre-event LiDAR-DTM, provided a DoD (DTM of Difference) that was useful to assess the deposition-erosion patterns and estimate debris-flow volume. Multi-temporal topographical data are important to analyze the phenomenon and its characteristics. This allowed us to more in depth analyzed the debris-flow effects and provide valuable information for the planning of risk prevention measures

Evaluación de la salud bucal del paciente previo al tratamiento ortodóncico

El uso de dispositivos de ortodoncia pone a los pacientes en condición de vulnerabilidad debido a que los mismos constituyen un nuevo hábitat de retención microbiana. Los principales problemas de los pacientes bajo tratamiento son la caries y la enfermedad periodontal, que tienen como factor esencial para su producción al biofilm bucal. Por esto, el ortodoncista tiene la necesidad de evaluar las patologías secundarias ocasionadas por el tratamiento con aparatología fija antes de comenzar cualquier terapia de ortodoncia. OBJETIVO: Evaluar las condiciones clínicas, sialoquímicas y microbiológicas de los pacientes al inicio del tratamiento ortodóncico, para adecuar la motivación de estos pacientes y las acciones clínicas que eviten patologías secundarias. MÉTODOS: Se trabajó con 15 pacientes adultos con necesidad de tratamiento ortodóncico, se confeccionó la historia clínica, se registraron parámetros clínicos (índice de caries, índice de higiene oral simplificado de Green y Vermillion, motivo de la consulta, biotipo facial) y se tomaron muestras de biofilm bucal y saliva para determinar parámetros microbiológicos (S.mutans, Lactobacillus spp. y Candida) y sialoquímicos (enzimas e iones).RESULTADOS:Los pacientes mostraron altos valores medios del índice de caries. El 80% presentó valores del índice de placa indicativos de mala higiene bucal. Las mujeres mostraron un pH salival significativamente menor que el de los varones (p=0,005). Los microorganismos aislados del sector anterior de la boca mostraron menores recuentos de microorganismos que en el sector posterior. Se observaron diferencias significativas entre los recuentos de S.mutans y Candida (p<0,0001).Sólo se aisló Candida en la zona posterior de la boca (35% de los pacientes) con mayores valores en varones que en mujeres (p=0,05). Los pacientes más jóvenes mostraron mayor cantidad de biofilm bucal y recuento de S.mutans significativamente mayor en los sectores anterior y posterior de la boca (p=0,05 y 0,006, respectivamente). CONCLUSIÓN: Este estudio muestra la necesidad de conocer el estado de salud bucal previo al tratamiento ortodóncico por parte del ortodoncista, con el fin de prevenir lesiones de descalcificación del esmalte dentario, frecuentemente observadas al finalizar los tratamientos ortodóncicos.http://www.saio.org.ar/archivos/Fil: Vera Cucchiaro, Verónica S. Universidad Nacional de Córdoba. Facultad de Odontología. Cátedra de Integral Niños y Adolescentes, Área Odontopediatría B; Argentina.Fil: Barembaum, Silvina Ruth. Universidad Nacional de Córdoba. Facultad de Odontología. Cátedra Introducción a la Física y Química Biológica B; Argentina.Fil: Azcurra, Ana Isabel. Universidad Nacional de Córdoba. Facultad de Odontología. Cátedra de Biología Celular B; Argentina.Fil: Bass Pluer, Alfredo A. Universidad Nacional de Córdoba. Facultad de Odontología. Cátedra Integral Niños y Adolescentes B. Área Ortodoncia; Argentina.Otras Ciencias de la Salu