Search

Total mastectomy for breast cancer treatment can be a cause of deformity and distress for patients, with severe impairment of self-esteem, body image, sexuality, and quality of life. In developing countries, immediate breast reconstruction is the gold standard, and there are only a few absolut contraindications for some technique of breast reconstruction. This article describes reconstructive options (flaps and alloplastic material), reconstructive timing, pros and cons of both techniques, potential complications, and an algorithm of treatment is proposed. Choice of the reconstructive technique should be decided by the patient and her surgeon, considering physical characteristics, factors related with the disease and oncologic treatments, and patients’ preferences. [ABSTRACT FROM AUTHOR]

An unusually intense atmospheric river affected the southern coastal region of British Columbia in mid-November 2021. Flooding and several ground failures such as landslides and riverbank erosion caused significant damage and interrupted the main transportation corridors, including major highways and railroads, severing land connectivity between Metro Vancouver and the rest of Canada. In this short note, we summarize and describe slope and riverbank ground failures in the Lower Mainland and connecting corridors to the interior such as the Fraser Canyon and the Coquihalla Valley, with focus on those that produced damage on highways. Field observations are discussed in the context of potential future similar disasters in the region due to more frequent extreme climatic events associated with climate change. [ABSTRACT FROM AUTHOR]

A ca. 2.5 million m3 landslide occurred in August 2018 in the Yerba Loca valley, Andes Main Cordillera (33° 15′ S), at about 4000 m a.s.l. The Yerba Loca landslide is a multirotational slide, with a main scarp and failure surface developed in a volcanic rock mass, with secondary scarps and tilted blocks disturbing the colluvial soil cover. No clear trigger could be identified, although the failure took place some weeks after the largest winter precipitation and a sequence of snowfall and snowmelt, in the context of a severe drought. Inspection of optical satellite images suggests that the landslide suffered slow deformation for at least 15 years, increasing in the months prior to the failure. To corroborate these precursor deformations, InSAR analyses were performed at two time and spatial scales. For over 3 years, deformation in the landslide area was detected, while the local, short-term analysis from the 7 months before failure shows line-of-sight deformation rates at the landslide site of over 10 cm/year. Deformation continues after the failure with decreasing speed, with indications of further activity and expansion of the failure zone. This implies a hazard of rock avalanche, debris flows and/or river damming and subsequent outburst floods that may endanger communities downstream. The Yerba Loca landslide is an example of rock slope failure in paraglacial conditions and the influence of climatic factors in the context of climate change for the central Andes. This event represents an opportunity for learning on landslide mechanisms, remote sensing monitoring and hazard assessment of slow, large volume landslides in the Andean highlands. [ABSTRACT FROM AUTHOR]

The co-seismic and post-seismic behaviour of pyroclastic ash deposits and its influence on slope stability remains as a challenging subject in engineering geology. Case studies in volcanic areas of the world suggest that soil structural changes caused by seismic shaking results in landslide activity. It is critical to constrain how this kind of soil behaves during coseismic ground shaking, as well as the effects of dynamic loading on shear strength parameters after shaking. Direct shear tests carried out on cineritic volcanic materials from the Pudahuel Ignimbrite formation in central Chile show a direct effect of cyclic loading on the shear strength and in a minor extent on the rheology. A high apparent cohesion found in monotonic shear tests, likely attributed to suction and cementation, is destroyed by dynamic loading. At the same time, the internal friction angle rises. This defines a differential post-dynamic behaviour depending on normal effective stress conditions, which favour the occurrence of shallow landslides. These results show how the use of shear strength parameters obtained from standard monotonic direct shear tests may produce misleading results when analysing seismic slope stability in this type of soils. [ABSTRACT FROM AUTHOR]

A landslide cluster located in the Pangal river valley, Cachapoal river basin, in the Andes of central Chile is investigated. Deposits of five rock avalanche deposits of volumes varying from 1.5 to 150 million cubic metres are distinguished by detailed geomorphological mapping and dating. The landslides were originated in volcanic rocks affected by hydrothermal alteration. The largest three avalanche deposits, formerly considered as a single deposit, were dated using Terrestrial Cosmogenic Nuclide methods. The results show three distinct ages from Late Pleistocene to Holocene, confirming the hypothesis of separate events. The presence of clay minerals detected by X-ray diffraction in matrix samples confirm the presence of hydrothermal alteration in the landslide source areas detected by satellite image multispectral analyses, suggesting an important control of such alteration in the landslide generation. The present river morphology and outcrops of lacustrine deposits and outburst terraces evidence that the largest rock avalanches, with deposit thicknesses of up to about 100 m, have dammed the valley to be later eroded by the Pangal river. The repetition of large volume landslides in the valley and their potential of river damming should be considered as a hazard that may endanger critical infrastructure and human settlements downstream. This case study is an example of potential hazards of large slope collapses and related river damming in the Chilean Andes that should be addressed in more depth along with further investigations on the landslide controlling factors and failure mechanisms in the region. • A landslide cluster of five rock avalanches of Late Pleistocene to Holocene age is identified. • Detailed mapping and dating allow distinction of landslide deposits previously considered a single deposit. • Hydrothermal alteration plays an important control on the generation of rock slides. • Example of large rock collapse and potential river damming hazards in the Andes. [ABSTRACT FROM AUTHOR]

In January and February 2013, heavy rainfall during local summer storms triggered a large number of landslides in the Andes Main and Frontal ranges of central Chile and Argentina (32°-34° S). Most of the mass movements classify as debris flows, while rockfalls and debris avalanches also occurred. The major debris flows occurred in the Maipo and Aconcagua valleys (Chile) and along the Mendoza River valley (Argentina). The debris flows caused serious disruption to the international highway connecting both countries and local roads and produced a large impact on the population of major cities downstream, mainly due to potable water supply cutoffs. Debris flow deposits have silt and clay particles usually ranging between 10 and 20 % by weight, which favors the movement of viscous flows in short, steep lateral gullies. Most of the flows tended to channelize, and the materials were deposited in alluvial fans and cones in areas with previous records of such events. This indicates that they constitute a significant hazard that may not have been properly considered in road infrastructure and potable water supply strategies for the region. This potential hazard may become more serious due to climate change in the near future. [ABSTRACT FROM AUTHOR]

In March 2012, during the rainy season in the Altiplano plateau, a >100-year return period rainfall event affected the deeply incised valleys of the Precordillera of the Tarapacá Region, northern Chile. This extreme event in a very arid region triggered a number of debris and mud flows that caused severe damage and destruction in several small villages along the Camiña and Tarapacá valleys. The highly vulnerable location of the villages on top of alluvial fans due to socioeconomic and cultural reasons is a key factor to explain the level of destruction in most villages. In this paper, this unusual, remarkable landslide event is described, and the hazard faced by these settlements for future rainfall episodes and possible mitigation measures are discussed. [ABSTRACT FROM AUTHOR]

Abstract: Debris flows are an important type of geological hazard in Chile, affecting cities, towns and rural areas throughout the country despite the variation in climate regimes. In this summary paper, recent debris flows in the cities of Antofagasta and Santiago, in northern and central Chile, and in a rural area near Lake Ranco in central-southern Chile in 1991, 1993 and 2004, respectively, are reviewed. Triggering factors for flow occurrence are identified and different approaches to debris flow hazard assessment and the effects of debris flows on people and the environment are discussed. Furthermore, the relationships between debris flow occurrence and climatic anomalies such as El Niño episodes are analysed. A clear pattern of debris flow generation associated with El Niño events is found for Antofagasta and Santiago. The risk related to debris flows in Chile is of increasing importance because of the continuous expansion of cities to hazardous areas such as alluvial fans. The results show that hazard assessment based on several factors is essential for the implementation of proper prevention and mitigation measures for future debris flow events in the country. [Copyright &y& Elsevier]

Abstract: The 1994 Northridge earthquake (M w =6.7) triggered extensive rock slope failures in Pacoima Canyon, immediately north of Los Angeles, California. Pacoima Canyon is a narrow and steep canyon incised in gneissic and granitic rocks. Peak accelerations of nearly 1.6 g were recorded at a ridge that forms the left abutment of Pacoima Dam; peak accelerations at the bottom of the canyon were less than 0.5 g, suggesting the occurrence of topographic amplification. Topographic effects have been previously suggested to explain similarly high ground motions at the site during the 1971 (M w =6.7) San Fernando earthquake. Furthermore, high landslide concentrations observed in the area have been attributed to unusually strong ground motions rather than higher susceptibility to sliding compared with nearby zones. We conducted field investigations and slope stability back-analyses to confirm the impact of topographic amplification on the triggering of landslides during the 1994 earthquake. Our results suggest that the observed extensive rock sliding and falling would have not been possible under unamplified seismic conditions, which would have generated a significantly lower number of areas affected by landslides. In contrast, modelling slope stability using amplified ground shaking predicts slope failure distributions matching what occurred in 1994. This observation confirms a significant role for topographic amplification on the triggering of landslides at the site, and emphasises the need to select carefully the inputs for seismic slope stability analyses. [Copyright &y& Elsevier]

This review paper compiles research related to debris flows and hyperconcentrated flows in the central Andes (30°–33° S), updating the knowledge of these phenomena in this semiarid region. Continuous records of these phenomena are lacking through the Andean region; intense precipitations, sudden snowmelt, increased temperatures on high relief mountain areas, and permafrost degradation are related to violent flow discharges. Documented catastrophic consequences related to these geoclimatic events highlight the need to improve their understanding in order to prepare the Andean communities for this latent danger. An amplified impact is expected not only due to environmental changes potentially linked to climate change but also due to rising exposure linked to urban expansion toward more susceptible or unstable areas. This review highlights as well the need for the implementation of preventive measures to reduce the negative impacts and vulnerability of the Andean communities in the global warming context. [ABSTRACT FROM AUTHOR]

In this paper, we study natural hazards and their potential impacts on productive activities in the Comau Fjord in Chilean Northern Patagonia. We carried out hazard mapping to identify areas with evidence of geomorphological activity on slopes in terms of landslides, river/tsunami flooding, and glacial retreat. The assessment of different geomorphic processes was carried out by both detailed fieldwork and analysis of satellite remote sensing and aerial photography information. We identified terrain units that are subject to multi-hazards overlapping different spatially distributed hazard maps. This information was overlaid with spatial data of economic activities in the area in order to establish the impacts of the natural hazards on the local salmon and mussel farming infrastructure (risk). The results suggest significant exposure levels for these productive activities and potential damage due to the occurrence of natural hazards. The extension of a major highway (CH-7 Austral Highway) on the east coast of the Comau Fjord will be a new incentive for economic development in the area. However, the highway construction sites show a high level of exposure to natural hazards, especially floodings and landslides. Our study highlights that the geohazard potential might have a high negative impact on future productive activity in the fjord as well as on the new highway infrastructure. [ABSTRACT FROM AUTHOR]

The 2010 Mw = 8.8 Maule earthquake, which occurred in the subduction contact between the Nazca and the South American tectonic plates off the coast of Chile, represents an important opportunity to improve understanding of the distribution and controls for the generation of landslides triggered by large megathrust earthquakes in subduction zones. This paper provides the analysis of the comprehensive landslide inventory for the Maule earthquake between 32.5° S and 38.5° S. In total, 1226 landslides were mapped over a total area of c. 120,500 km2, dominantly disrupted slides. The total landslide volume is c. 10.6 Mm3. The events are unevenly distributed in the study area, the majority of landslides located in the Principal Andean Cordillera and a very constrained region near the coast on the Arauco Peninsula, forming landslide clusters. Statistical analysis of our database suggests that relief and lithology are the main geological factors controlling coseismic landslides, whilst the seismic factor with higher correlation with landslide occurrence is the ratio between peak horizontal and peak vertical ground accelerations. The results and comparison with other seismic events elsewhere suggest that the number of landslides generated by megathrust earthquakes is lower than events triggered by shallow crustal earthquakes by at least one or two orders of magnitude, which is very important to consider in future seismic landslide hazard analysis. [ABSTRACT FROM AUTHOR]

As one of the main environmental effects of earthquakes, the distribution of landslides could reflect regional neotectonic activity. To that end, we carried out an inventory of landslides along the Precordillera range (31°-33°S) comprising the most seismically active region of Argentina. Main Quaternary deformation is concentrated in this Western central part of the country associated with active faults linked to intense shallow seismic activity (<35 km depth). During the last 150 years, the region has suffered at least six major earthquakes with a magnitude greater than M s ≥ 7.0. The main focus of this research is to analyse the distribution of landslides along this Andean active orogenic front and characterize the response of collapses. We analysed morphological parameters of these landslides. According to our results, collapses match with traces of active Quaternary faults in this region. Landslides are clustered however, being more densely splayed in the centre of the study area and decreasing gradually towards the North and the South. We propose that the Juan Fernandez Ridge trace promotes a higher rate of deformation in this area, matching with higher historical seismicity and distribution of landslides. [ABSTRACT FROM AUTHOR]

In this paper, static and dynamic analyses were performed considering the reconstituted geometry of a prehistoric 0.1 km 2 rockslide with an exposed stepped-planar failure surface using a distinct element code (UDEC®). The rockslide occurred on the northern slope of the Cerro Catedral mount, located in the headers of the Maipo river drainage basin (Main range of the Andes Cordillera) at the latitude of the Santiago city, Chile, between the Late Pleistocene and the Holocene. The remaining failure surface consists of two distinct sliding planes dipping at an angle of ~37° and connected by a sub-vertical step. The original geometry of the rock slope was estimated from a terrestrial laser scan elevation model (LIDAR), the deposit that remained in the valley, and the hill surface topography. The laser scan of the sliding surfaces and Schmidt hammer field measurements allowed the estimation of the sliding surface mechanical properties, whereas laboratory test results were used to estimate the rock mass material properties. Results from 2D static numerical analyses indicate that the rock slope requires the presence of at least one rock bridge at the sliding surface connecting step in order to be statically stable. Furthermore, we studied the effect of different acceleration time histories recorded during shallow crustal earthquakes, compatible with the regional seismicity, in the rockslide response. The dynamic numerical analyses show that the input earthquake records induce a pronounce topographic amplification in the rock slope, that the rockslide displacement highly correlates with the Arias Intensity, the peak velocity, and the peak acceleration calculated in the rock slope center of gravity, and that the rockslide may have been triggered by horizontal accelerations larger than 0.6 g in the free field. Finally, the slope's response is evaluated under the coupled action of horizontal and vertical accelerations. [ABSTRACT FROM AUTHOR]

Landslides typify one of the most hazardous natural phenomena fostering economic and even human losses worldwide. Several countries like Colombia, in South America, are hotspots for fatal landslides. In this contribution, we thoroughly reviewed four available databases, articles, grey literature and web resources, in order to build up a new catalogue of fatal landslides in Colombia. We gathered a catalogue of 2351 individual fatal landslides which caused about 37,959 deaths. Of these, we found 11 fatal events in historical times (pre-twentieth century). In modern times (1912–2020), we analysed landslides' spatial and temporal distribution, finding that in central-western Colombia, particularly in the departments of Caldas, Risaralda, Quindío and Antioquia, these kinds of events are more frequent. Upward trends in these areas and a nationwide increase in the number of events in the last 20 years suggest that fatal landslides are far from being effectively mitigated. Our findings also show a strong correlation between the climate variability phenomenon known as El Niño Southern Oscillation (ENSO) and fatal landslides, particularly during those years when strong La Niña (cold phase of ENSO) events occur. Despite rainfall being the most common trigger for fatal landslides, we observed an increasing trend in anthropogenically related events in the last decade. Finally, we obtained multiple socio-economic indices and ran a statistical analysis at the departmental level in order to assess whether impoverished and vulnerable people are more affected by fatal landslides. We propose that in most cases, departments with low income, high levels of corruption and inequality are usually more affected. [ABSTRACT FROM AUTHOR]

The southernmost portion of the Liquiñe-Ofqui fault zone (LOFZ) lies within the proposed slab window which formed due to oblique subduction of the Chile Ridge in Patagonia. Mapping of paleo-surface ruptures, offsets, and lithological separations along the master fault allowed us to constrain geologic slip rates for the first time with dextral rates of 11.6–24.6 mm/year (Quaternary) and 3.6–18.9 mm/year (Late-Cenozoic) respectively. We had trouble mapping the LOFZ in one local because of a partially collapsed and previously undiscovered volcanic complex, Volcan Mate Grande (VMG: 1,280 m high and thus Vesuvius-sized) that grew in a caldera also offset along the LOFZ and has distinct geochemistry from adjacent stratovolcanoes. Besides the clear seismic and volcanic hazard implications, the structural connection along the main trace of the fast slipping LOFZ and geochemistry of VMG provides evidence for the slab window and insight into interplay between fast-slipping crustal intra-arc crustal faults and volcanoes. [ABSTRACT FROM AUTHOR]

The southernmost portion of the Liquiñe-Ofqui fault zone (LOFZ) lies within the proposed slab window which formed due to oblique subduction of the Chile Ridge in Patagonia. Mapping of paleo-surface ruptures, offsets, and lithological separations along the master fault allowed us to constrain geologic slip rates for the first time with dextral rates of 11.6–24.6 mm/year (Quaternary) and 3.6–18.9 mm/year (Late-Cenozoic) respectively. We had trouble mapping the LOFZ in one local because of a partially collapsed and previously undiscovered volcanic complex, Volcan Mate Grande (VMG: 1,280 m high and thus Vesuvius-sized) that grew in a caldera also offset along the LOFZ and has distinct geochemistry from adjacent stratovolcanoes. Besides the clear seismic and volcanic hazard implications, the structural connection along the main trace of the fast slipping LOFZ and geochemistry of VMG provides evidence for the slab window and insight into interplay between fast-slipping crustal intra-arc crustal faults and volcanoes. [ABSTRACT FROM AUTHOR]

Author Correction: Liquiñe-Ofqui's fast slipping intra-volcanic arc crustal faulting above the subducted Chile Ridge VMG has distinctive La/Yb (C) and Dy/Yb (D) values, i.e. a completely different signature between VMG magmas and VH magmas. (F,G) DEMs and mapping from the VMG, showing the 5 km by 4 km caldera, the young partially collapsed cone, the rock avalanche deposits (QRa), Quaternary alluvium (Qal), and the location of the main trace of the LOFZ that cuts this cone and displaces the rock avalanche deposit (likely triggered by a LOFZ earthquake/rupture) northward (i.e. dextrally) by ~ 170 ± 20 m. [Extracted from the article]

This research project shows the implementation of classic digital controllers in an embedded system to control the temperature of a thermal system. The embedded system selected was in the computer board Raspberry Pi 2 B+ together with an ONE Arduino board. In the measurement stage the hardware was developed for to transmit the temperature data from the PT-100 thermometer resistance towards the Raspberry PI. For the implementation of the computational stage was developed an algorithm for the different controllers and based on this the controllers were programmed in Python 2.7. For the actuator a power stage was designed that converts th ac voltage into a voltage dc, from a PWM signal. This dc voltage is used to feed a thermal resistance that is responsible for executing the control action of the system. With the implementation of the types of controllers, a comparative analysis was realized highlighting the most relevant characteristics for each type of controller and allowing to also evaluate the performance of the Raspberry Pi. Based on the results obtained in the execution of the project, it concluded the feasibility to control thermal systems under different types of controllers embedded in the Raspberry Pi and with the possibility of developing intelligent control strategies for futures projects, through the use of software tools and free hardware. [ABSTRACT FROM AUTHOR]

Introduction: One of the most important outcomes in patients undergoing body-contouring surgery is quality of life. Data on long-term quality of life is deficient. The main purpose of this study is to determine if short-term QoL after body contouring surgery maintains in the long-term follow up. Methods: A cohort study was designed; patients with at least one-year follow-up from the surgery were included. Quality of life was measured with the Body-Qol© instrument. All patients answered the preoperative Body-Qol© and at least one measurement after one year of follow-up from body contouring surgery. The preoperative scores, short-term scores and long-term followup scores were compared. The statistical analysis was made with Kruskal-Wallis y Kolmogorov- Smirnov tests. Results: The cohort was integrated by 112 patients; the long-term follow-up was of 75%. Quality of life improved between the preoperative measure (43.9 ± 14.1 points) and both short-term and long-term measures (85.2 ± 16.8 early postoperative y 83.6 ± 13.5 late postoperative), which was statistically significant (P < .0001). There was no difference between the short-term and long-term measures (P = .112). The domain analysis demonstrated the same tendency. Massive weight loss patients had lower preoperative scores but improved more after BCS, reaching almost cosmetic values. Conclusions: Quality of life improves soon after surgery and is stable over time. This was observed for both massive weight loss and cosmetic patients. [ABSTRACT FROM AUTHOR]

Objective: To determine the changes in the quality of life of women subjected to augmentation mammoplasty or a prosthesis mastopexy, using the validated tool Breast-Q®. Materials and methods: A prospective cohorts study was conducted that included operated on for augmentation mammoplasty or augmentation mastopexy in the Hospital Clínico de la Universidad de Chile (HCUCH) between October 2013 and May 2014. The quality of life (QoL) was measured using the Breast-Q® validated tool. Descriptive and analytic statistics were performed to evaluate the overall change in QoL and by domains, considering a p<.05 as statistically significant. Results: A total of 58 patients were operated on, of whom 33 (56.9%) completed the BreastQ® questionnaire before surgery, and 25 (75.7%) of them in the post-operative period. The quality of life increased from 49.7% to 82.5% (p<.001). When analysed by domain, there was an improvement in Self-esteem (52% to 88%, p<.001), Self-image (22% to 80%, p<.001) and Sex Life (31% to 86%, p<.001). The physical symptoms increased from 75% to 94% (p<.001). Conclusions: Breast augmentation improves the quality of life, in particular, self-esteem, selfimage, and sex life, but physical discomforts increased. The overall satisfaction was high. [ABSTRACT FROM AUTHOR]

Background: The deformity caused by facial paralysis has important functional and psychological consequences. Aim: To report a face reanimation protocol and the results of surgical treatment of facial paralysis. Materials and methods: Prospective intervention of 25 patients aged 8 to 79 years (13 males) with facial paralysis, between 2008 and 2014. Surgical results were evaluated using measurements according to Mantkelow protocol. Results: Patients were followed for 22 months. Postoperative excursion of the labial commissure reached 12.8 mm, which was 7 mm better than before surgery. The postoperative excursion of the upper lip was 5.9 cm, which also represented an improvement. Conclusions: There is a significant improvement in facial movements in these patients subjected to the face reanimation protocol. Although changes are of low magnitude, they have an impact in their quality. [ABSTRACT FROM AUTHOR]

This work presents the results of a regional-scale estimation of low-enthalpy geothermal resources for district heating in the Santiago basin. The purpose of this work is to identify promising areas for the development of this type of renewable energy. The estimation was based on comparison of soil thermal properties and hydrogeological parameters, using Geographic Information System (GIS). To determine the geothermal potential, Ground Source Heat Exchanger (GSHE) coupled with heat pump was used to supply a fixed demand equivalent to the energy required to heat a Chilean standard house. The main barrier for the implementation of a GSHE coupled with heat pump is the well drilling cost, therefore the potential is presented as meters to be drilled in order to install 2 types of GSHE: 1) Borehole Heat Exchanger (BHE) and 2) Groundwater Heat Exchanger (GWHE). To assess the BHE, we used specific Heat Extraction (sHE) of sediments. To evaluate a GWHE, we used depth of groundwater table and groundwater drawdown caused by pumping water to the heat pump. The depth to be drilled ranges from 35 to 105 m in case of the BHE, while in case of the GWHE it ranges from 10 to 400 m. [ABSTRACT FROM AUTHOR]

Objetivo Determinar el cambio en calidad de vida en mujeres sometidas a reducción mamaria y explorar sus factores determinantes. Materiales y métodos Se realizó un estudio de cohorte prospectiva con todas las pacientes que ingresaron al Hospital Clínico de la Univeridad de Chile (HCUCH) y se sometieron a reducción mamaria por cualquier técnica desde julio de 2013 a abril de 2014. La calidad de vida (CdV) se midió con el intrumento validado Breast-Q Reduction and Mastopexy Module. Se utilizó estadística descriptiva para caracterizar la muestra y analítica para determinar el cambio en CdV y sus factores pronósticos. [ABSTRACT FROM AUTHOR]