Time-lapse photography of the edge-of-water line displacements of a sandbar as a proxy of riverine morphodynamics

A simple methodology to track the displacements of a sandbar from a fixed video camera, extracting its morphological features and deriving the associated fluvial morphology is presented, using a small reach of the Po River in Italy as a case study. A camera fixed on a bridge pier acquired images every twelve hours while hourly water levels are derived from a radar hydrometer located upstream of the study area. The quantification of the fluvial bathymetry is achieved by mapping multiple edge-of-water lines of a sandbar before and after high flow conditions in December 2017. Both from video information and 2-D numerical simulations, it is evident that flooding waves can easily remove sediments that accumulated on bars during low flow conditions in this area, redistributing them across the river channel. This video-based methodology-which confirms to be economically attractive if compared to more traditional monitoring systems-proves to be a valuable system to monitor long-term fluvial processes providing detailed indications on how to better plan river management activities

Long-term Morphodynamics of a Schematic River Analysed with a Zero-dimensional, Two-reach, Two-grainsize Model

Abstract. At the basin scale, neglecting localized deviations caused by geological constraints like knick-points, alluvial rivers commonly exhibit a concave profile and a progressive sediment fining in the downstream direction. Although this configuration is, perforce, not in equilibrium, yet it usually shows a quasi-stationary behaviour at the very long (historical and geological) time-scale. A zero-dimensional, two-reach, two-grainsize hydro-morphological model is presented and applied to a schematic river. The description of the processes involved is done assuming several reasonable and verified simplifications, giving reason of the extremely slow evolution of many alluvial rivers and providing a quantitative approach to evaluate their response time. Different from previous analytical formulations, the response time appears here to be affected, among others, by the granulometry of the sediment input. Applications of the model to different geometries demonstrate that the present riverine morphology at the basin scale will persist practically stationary for extremely long periods of time (centuries and even millennia), if the climatic forcing remain unchanged and no anthropogenic perturbations are introduced in the system

Deriving planform morphology and vegetation coverage from remote sensing to support river management applications

With the increasing availability of big geospatial data (e.g., multi-spectral satellite imagery) and access to platforms that support multi-temporal analyses (e.g., cloud-based computing, Geographical Information Systems, GIS), the use of remotely sensed information for monitoring riverine hydro-morpho-biodynamics is growing. Opportunities to map, quantify and detect changes in the wider riverscape (i.e., water, sediment and vegetation) at an unprecedented spatiotemporal resolution can support flood risk and river management applications. Focusing on a reach of the Po River (Italy), satellite imagery from Landsat 5, 7 and 8 for the period 1988-2018 were analyzed in Google Earth Engine (GEE) to investigate changes in river planform morphology and vegetation dynamics associated with transient hydrology. An improved understanding of these correlations can help in managing sediment transport and riparian vegetation to reduce flood risk, where biogeomorphic processes are commonly overlooked in flood risk mapping. In the study, two established indices were analyzed: the Modified Normalized Difference Water Index (MNDWI) for monitoring changes in the wetted river planform morphology, inferring information about sediment dynamics, and the Normalized Difference Vegetation Index (NDVI) for evaluating changes in vegetation coverage. Results suggest that planform changes are highly localized with most parts of the reach remaining stable. Using the wetted channel occurrence as a measure of planform stability, almost two-thirds of the wetted channel extent (total area = 86.4 km2) had an occurrence frequency > 90% (indicating stability). A loss of planform complexity coincided with the position of former secondary channels, or zones where the active river channel had narrowed. Time series analysis of vegetation dynamics showed that NDVI maxima were recorded in May/June and coincided with the first peak in the hydrological regime (occurring in late spring and associated with snowmelt). Seasonal variation in vegetation coverage is potentially important for local hydrodynamics, influencing flood risk. We suggest that remotely sensed information can provide river scientists with new insights to support the management of highly anthropized watercourses

Influence of vegetation maintenance on flow and mixing: case study comparing fully cut with high-coverage conditions

In temperate climates, agricultural ditches are generally bounded by seasonal vegetation, which affects the hydrodynamics and mixing processes within the channel and acts as a buffer strip to reduce a load of pollutants coming from the surrounding cultivated fields. However, even if the control of such vegetation represents a key strategy to support sediment and nutrient management, the studies that investigated the effect of different vegetation maintenance scenarios or vegetation coverage on the flow and mixing dynamics at the reach scale are very limited. To overcome these limitations and provide additional insights into the involved processes, tracer tests were conducted in an agricultural ditch roughly 500 m long close to Warsaw in Poland, focusing on two different vegetation scenarios: highly vegetated and fully cut. Under the highly vegetated scenario, sub-reaches differing in surficial vegetation coverage are analysed separately to better understand the influence of the vegetation conditions on the flow and mixing parameters. Special attention has been paid to the longitudinal dispersion coefficient in complex natural conditions and its dependency on vegetation coverage (V). The vegetation maintenance decreased the travel and residence times of the solute by 3–5 times, moderately increasing the peak concentrations. We found that the dispersion coefficient decreased approximately linearly with the increase of vegetation coverage at V&gt;68 %. Further research is needed at lower vegetation coverage values and different spatial plant distributions. The obtained longitudinal dispersion coefficient values complement dispersion value datasets previously published in the literature, which are barely available for small natural streams. The new process understanding supports the design of future investigations with more environmentally sound vegetation maintenance scenarios.</p

River Morphodynamic Evolution Under Dam-Induced Backwater : An Example from the Po River (Italy)

Peer reviewedPostprin

Complex structural rearrangements are present in high-grade dysplastic Barrett\u27s oesophagus samples

Background: Oesophageal adenocarcinoma (EAC) incidence is increasing and has a poor survival rate. Barrett’s oesophagus (BE) is a precursor condition that is associated with EAC and often occurs in conjunction with chronic gastro-oesophageal reflux, however many individuals diagnosed with BE never progress to cancer. An understanding of the genomic features of BE and EAC may help with the early identification of at-risk individuals. Methods: In this study, we assessed the genomic features of 16 BE samples using whole-genome sequencing. These included non-dysplastic samples collected at two time-points from two BE patients who had not progressed to EAC over several years. Seven other non-dysplastic samples and five dysplastic BE samples with high-grade dysplasia were also examined. We compared the genome profiles of these 16 BE samples with 22 EAC samples. Results: We observed that samples from the two non-progressor individuals had low numbers of somatic single nucleotide variants, indels and structural variation events compared to dysplastic and the remaining non-dysplastic BE. EAC had the highest level of somatic genomic variations. Mutational signature 17, which is common in EAC, was also present in non-dysplastic and dysplastic BE, but was not present in the non-progressors. Many dysplastic samples had mutations in genes previously reported in EAC, whereas only mutations in CDKN2A or in the fragile site genes appeared common in non-dysplastic samples. Rearrangement signatures were used to identify a signature associated with localised complex events such as chromothripsis and breakage fusion-bridge that are characteristic of EACs. Two dysplastic BE samples had a high contribution of this signature and contained evidence of localised rearrangements. Two other dysplastic samples also had regions of localised structural rearrangements. There was no evidence for complex events in non-dysplastic samples. Conclusions: The presence of complex localised rearrangements in dysplastic samples indicates a need for further investigations into the role such events play in the progression from BE to EAC

Comorbidades e evolução clínica em pacientes críticos com COVID-19 atendidos em hospital regional do Planalto Norte Catarinense

Regarding the epidemiological scenario of coping with COVID-19, it is important to consider the importance and lack of regional epidemiological data in Santa Catarina (SC) – Brazil. Therefore, the present study aimed to study and discuss comorbidities, epidemiological data, and outcome in patients with COVID19 treated and hospitalized in the intensive care unit (ICU) of a regional hospital in the northern plateau of Santa Catarina (SC). Through retrospective investigative and descriptive analysis, using data indexed in medical records (from March to December 2020) of patients hospitalized in ICU-Covid19, we studied the clinical characteristics and intra-hospital evolutions. In this population, it was found that epidemiological indicators such as gender, risk factors and mortality agree with those described worldwide, which were: higher prevalence of males, without significant differences in relation to age in relation to females. However, there was a significant difference in relation to the mean age of the population that evolved to death in relation to the population that evolved to hospital discharge. Regional epidemiological studies support health, disease, and health market data indicators that are summarily important for the development of health strategies and planning. Thus, the present study aims to contribute to the knowledge of this scenario in the health region in question, as well as the global epidemiological scenario of this disease condition.Quanto ao cenário epidemiológico de enfrentamento da COVID-19, é importante considerar a importância e carência de dados epidemiológicos regionais de Santa Catarina (SC) – Brasil. Diante disso, o presente estudo teve como objetivo estudar e discutir comorbidades, dados epidemiológicos e desfecho em pacientes com COVID19 atendidos e internados em unidade de terapia intensiva (UTI) de um hospital regional de planalto norte catarinense (SC). Por meio de análise investigativa e descritiva, do tipo retrospectiva, utilizando-se de dados indexados em prontuários médicos (de março à dezembro de 2020) de pacientes internatos em UTI-Covid19, estudou-se sobre as características clínicas e evoluções intra hospitalar. Nessa população, verificou-se que indicadores epidemiológicos como sexo, fatores de risco e mortalidade estão de acordo com os mundialmente descritos, os quais foram: maior prevalência de indivíduos do sexo masculino, sem diferenças significativas em relação à faixa etária em relação ao sexo feminino. No entanto, houve diferença significativa em relação à média de idade da população que evoluiu para óbito em relação à população que evoluiu para alta hospitalar. Estudos epidemiológicos regionais apoiam indicadores de saúde, doença e dados do mercado de saúde que são sumariamente importantes para o desenvolvimento de estratégias e planejamento de saúde. Dessa forma, o presente estudo visa contribuir para o conhecimento desse cenário na região de saúde em questão, bem como do cenário epidemiológico mundial dessa condição de doença

Complex structural rearrangements are present in high-grade dysplastic Barrett’s oesophagus samples

This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.Abstract Background Oesophageal adenocarcinoma (EAC) incidence is increasing and has a poor survival rate. Barrett’s oesophagus (BE) is a precursor condition that is associated with EAC and often occurs in conjunction with chronic gastro-oesophageal reflux, however many individuals diagnosed with BE never progress to cancer. An understanding of the genomic features of BE and EAC may help with the early identification of at-risk individuals. Methods In this study, we assessed the genomic features of 16 BE samples using whole-genome sequencing. These included non-dysplastic samples collected at two time-points from two BE patients who had not progressed to EAC over several years. Seven other non-dysplastic samples and five dysplastic BE samples with high-grade dysplasia were also examined. We compared the genome profiles of these 16 BE samples with 22 EAC samples. Results We observed that samples from the two non-progressor individuals had low numbers of somatic single nucleotide variants, indels and structural variation events compared to dysplastic and the remaining non-dysplastic BE. EAC had the highest level of somatic genomic variations. Mutational signature 17, which is common in EAC, was also present in non-dysplastic and dysplastic BE, but was not present in the non-progressors. Many dysplastic samples had mutations in genes previously reported in EAC, whereas only mutations in CDKN2A or in the fragile site genes appeared common in non-dysplastic samples. Rearrangement signatures were used to identify a signature associated with localised complex events such as chromothripsis and breakage fusion-bridge that are characteristic of EACs. Two dysplastic BE samples had a high contribution of this signature and contained evidence of localised rearrangements. Two other dysplastic samples also had regions of localised structural rearrangements. There was no evidence for complex events in non-dysplastic samples. Conclusions The presence of complex localised rearrangements in dysplastic samples indicates a need for further investigations into the role such events play in the progression from BE to EAC