Large pieces of in-channel wood can exert an important role on the ecological and morphological properties of gravel-bed rivers. On the other side, when transported during flood events, large wood ...can become a source of risk for sensitive structures such as bridges. However, wood displacement and velocity in river systems are still poorly understood, especially in large gravel-bed rivers. This study focuses on log transport in a valley reach of Tagliamento River (Italy). Log displacement during flood events of different magnitudes recorded from June 2010 to October 2011 has been analysed thanks to the installation of 113 radio frequency identification (RFID) tags and 42 GPS tracker devices in logs of different dimensions. Recovery rates of logs equipped with RFID and GPS trackers were about 43% and 42%, respectively. The GPS devices allowed us to analyse in details the log displacement and transport overtime, indicating a higher log entrainment during rising limb of hydrographs. The threshold for the entrainment of logs from low bars is around 40% of bankfull water stage. No clear relationship was found between the peak of flood and log displacement length and velocity. However, log displacement length and velocity appear significantly correlated to the ratio between the peak of flow and the water stage exceeding the flow duration curve for 25% of time (i.e. the ratio hmax/h25 ratio). Log deposition was observed to occur at the peak flow, and logs transported during ordinary events are preferably deposited on low bars. This study reveals the potentials of GPS tracker devices to monitor the entrainment and movements of logs in large gravel-bed rivers during floods. These observations could be useful for better planning of river management practices and strategies involving the use of large wood pieces and could help for calibrating wood budgets at the reach scale.
•Log entrainment and transport have been analysed in the Tagliamento River.•Log movement during floods has been analysed using RFID and GPS tracker devices.•Logs in low bars are entrained at around 40% of bankfull stage in the Tagliamento River.•Logs are transported mainly during the rising limb of flood events.•Log transport distance and velocity are weakly related with flood peak stage.
Since its inception in 1986, the field of atomic force microscopy (AFM) has enabled surface analysis and characterisation with unparalleled resolution in a wide variety of environments. However, the ...technique is limited by very low sample throughput and temporal resolution making it impractical for materials science research on macro sized or time evolving samples such as the observation of corrosion. The potential of AFM sparked intense efforts to overcome these limitations shortly after its invention, and has led to the development of high-speed atomic force microscopes (HS-AFMs). Within the last 5 years the technology underpinning these instruments has matured to the point where routine imaging can achieve megapixels per second over scan areas of square millimetres, removing the limitations from AFM for industrial scale materials characterisation. This review explains the technology and looks to the future use of HS-AFMs in materials science.
Braided rivers are dynamic and complex environments shaped by the balance of the flow and sediment regimes and by the influence of the riparian vegetation and disturbances such as floods. In ...particular, the balance between sediment supply and transport capacity can determine the morphological evolution of a river. For instance, aggrading and widening trends are distinctive of reaches where sediment supply is higher than transport capacity. In contrast, incising and narrowing tendencies are dominant. The aim of the present study is to analyze the short-term morphological dynamics and the processes of erosion and sediment deposition along a small reach of a relatively unimpacted gravel-bed braided river (Tagliamento River, northeast Italy) using a terrestrial laser scanner (TLS). The study area is around 23ha and has been surveyed before after two periods with relevant flood events, two of which were higher than the bankfull level and occurred between September 2010 and September 2011. The very high point clouds density allowed us to derive three high resolution digital elevation models (DEMs) with 0.125×0.125m pixel size. Scan data cloud merging was achieved with an overall high degree of accuracy and resolution (subcentimeter). Topographic data were more accurate for exposed surfaces than those collected in wet areas. A detailed net of dGPS control points allowed us to verify the high quality of the DEMs derived from the surveys (RMSE of about 5cm). Two DEMs of difference (DoD) were computed, revealing different and consistent episodes of erosion and deposition within the analyzed area, and changes in morphology of channel and bars could also be detected, such as bar edge accretion and bank erosion demonstrating a strong dynamicity of the Tagliamento River. Moreover, a very detailed estimation of the surface roughness in the study area has been carried out, permitting a large-scale analysis of the roughness values distribution. The results of the analysis on the TLS collected data show that along a river with a high natural character (i.e., Tagliamento River), the dynamic processes are also common during low magnitude events.
The timing and extent of the morphological changes that occurred in the last 200
years in a large gravel bed river (the Piave River, eastern Italian Alps) that was heavily impacted by human ...activities (training structures, hydropower schemes, and gravel mining) have been analyzed by historical maps, aerial photos, repeated topographic measurements, and geomorphological surveys. Results show that the channel underwent a strong narrowing during the twentieth century, but with a faster pace during the 1970s–1990s and with an associated shift from a dominant braided pattern to a wandering morphology. Bed incision up to 2
m — mostly from gravel mining — has been documented for this period. Large areas of the former active channel were colonized by riparian forests, both as islands and as marginal woodlands. The ceasing of gravel extraction in the late 1990s seems to have determined a reversal in the evolutionary trend, with evidence of vegetation erosion/channel widening even though a significant aggradation phase is not present. We conclude that alteration of sediment regime has played a major role on the long-term channel evolution. However, only relevant flood events (
RI
>
10–15
years) appear to determine substantial island erosion, and therefore the proportion of island vs. channel area fluctuates depending on flood history.
The current study aimed to: (i) describe the extent of overall stigma as well as the differences in stigma towards people with alcohol abuse, dementia, depression, schizophrenia and obsessive ...compulsive disorder, as well as (ii) establish the dimensions of stigma and examine its correlates, in the general population of Singapore, using a vignette approach.
Data for the current study came from a larger nation-wide cross-sectional study of mental health literacy conducted in Singapore. The study population comprised Singapore Residents (Singapore Citizens and Permanent Residents) aged 18-65 years who were living in Singapore at the time of the survey. All respondents were administered the Personal and Perceived scales of the Depression Stigma scale and the Social Distance scale to measure personal stigma and social distance, respectively. Weighted mean and standard error of the mean were calculated for continuous variables, and frequencies and percentages for categorical variables. Exploratory structural equation modelling and confirmatory factor analysis were used to establish the dimensions of stigma. Multivariable linear regressions were conducted to examine factors associated with each of the stigma scale scores.
The mean age of the respondents was 40.9 years and gender was equally represented (50.9% were males). The findings from the factor analysis revealed that personal stigma formed two distinct dimensions comprising 'weak-not-sick' and 'dangerous/unpredictable' while social distance stigma items loaded strongly into a single factor. Those of Malay and Indian ethnicity, lower education, lower income status and those who were administered the depression and alcohol abuse vignette were significantly associated with higher weak-not-sick scores. Those of Indian ethnicity, 6 years of education and below, lower income status and those who were administered the alcohol abuse vignette were significantly associated with higher dangerous/unpredictable scores. Those administered the alcohol abuse vignette were associated with higher social distance scores.
This population-wide study found significant stigma towards people with mental illness and identified specific groups who have more stigmatising attitudes. The study also found that having a friend or family member with similar problems was associated with having lower personal as well as social distance stigma. There is a need for well-planned and culturally relevant anti-stigma campaigns in this population that take into consideration the findings of this study.
The compound hazard effects of multiple process cascades severely affect Chilean river systems and result in a large variety of disturbances on their ecosystems and alterations of their ...hydromorphologic regimes leading to extreme impacts on society, environment and infrastructure. The acute, neo-tectonically pre-determined susceptibility to seismic hazards, the widespread volcanic activity, the increasing glacier retreat and the continuous exposure to forest fires clearly disturb entire riverine systems and concur to trigger severe floods hazards. With the objective to refine the understanding of such cascading processes and to prospect feasible flood risk management strategies in such a rapidly changing environment we first classify the large river basins according to a set of disturbances (i.e. volcanic eruptions, earthquakes, glacier lake outburst floods, wild fires and mass movements). Then, we describe emblematic cases of process cascades which affected specific Chilean drainage basins and resulted in high losses as tangible examples of how the cascading processes may unfold in other river basins with similar characteristics. As an attempt to enrich the debate among management authorities and academia in Chile, and elsewhere, on how to sustainably manage river systems, we: a) highlight the pivotal need to determine the possible process cascades that may profoundly alter the system and b) we suggest to refine hazard and risk assessments accordingly, accounting for the current and future exposure. We advocate, finally, for the adoption of holistic approaches promoting anticipatory adaptation which may result in resilient system responses.
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•Several Chilean rivers are disturbed by the compound effects of multiple hazard processes•Process cascades in a changing environment may result in extreme floods and complex geomorphic adjustments•Chilean river basins are classified according to the number of different disturbances they are subjected to•Paradigmatic examples of occurred process cascades are presented, described and discussed•Adaptations of hazard and risk assessment procedures are necessary to account for such process interactions
The timing and extent of the morphological changes that occurred in the last 200years in a large gravel bed river (the Piave River, eastern Italian Alps) that was heavily impacted by human activities ...(training structures, hydropower schemes, and gravel mining) have been analyzed by historical maps, aerial photos, repeated topographic measurements, and geomorphological surveys. Results show that the channel underwent a strong narrowing during the twentieth century, but with a faster pace during the 1970s–1990s and with an associated shift from a dominant braided pattern to a wandering morphology. Bed incision up to 2m — mostly from gravel mining — has been documented for this period. Large areas of the former active channel were colonized by riparian forests, both as islands and as marginal woodlands. The ceasing of gravel extraction in the late 1990s seems to have determined a reversal in the evolutionary trend, with evidence of vegetation erosion/channel widening even though a significant aggradation phase is not present. We conclude that alteration of sediment regime has played a major role on the long-term channel evolution. However, only relevant flood events (RI>10–15years) appear to determine substantial island erosion, and therefore the proportion of island vs. channel area fluctuates depending on flood history.
High-speed atomic force microscopy (AFM) is important for following processes that occur on sub-second timescales for studies both in biology and materials science, and also for the ability to ...examine large areas of a specimen at high resolution in a practical length of time. Further developments of the previously reported high-speed contact-mode AFM are described. Two instruments are presented: (i) a high-speed flexure stage arrangement capable of imaging at a video rate of 30 fps, and (ii) an ultra-high speed instrument using a combined tuning fork and flexure-stage scanning system capable of ultra-high-speed imaging in excess of 1000 fps. Results of imaging collagen fibres under ambient conditions at rates of up to 1300 frames s-1 are presented. Despite tip-specimen relative velocities of up to 200 mm s-1, no significant damage to the collagen specimen was observed even after tens of thousands of frames were acquired in the same area of the specimen.
The ability to recognise a mental illness has important implications as it can aid in timely and appropriate help-seeking, and ultimately improve outcomes for people with mental illness. This study ...aims to explore the association between recognition and help-seeking preferences and stigmatising attitudes, for alcohol abuse, dementia, depression, obsessive-compulsive disorder (OCD) and schizophrenia, using a vignette-based approach.
This was a population-based, cross-sectional survey conducted among Singapore Residents (n = 3006) aged 18-65 years. All respondents were asked what they think is wrong with the person in the vignette and who they should seek help from. Respondents were also administered the Personal and Perceived sub scales of the Depression Stigma Scale and the Social Distance Scale. Weighted frequencies and percentages were calculated for categorical variables. A series of multiple logistic and linear regression models were performed separately by vignette to generate odd ratios and 95% confidence intervals for the relationship between help-seeking preference, and recognition and beta coefficients and 95% confidence intervals for the relationship between stigma and recognition.
Correct recognition was associated with less preference to seek help from family and friends for depression and schizophrenia. Recognition was also associated with increased odds of endorsing seeking help from a psychiatric hospital for dementia, depression and schizophrenia, while there was also an increased preference to seek help from a psychologist and psychiatrist for depression. Recognition was associated with less personal and perceived stigma for OCD and less personal stigma for schizophrenia, however, increased odds of social distancing for dementia.
The ability to correctly recognise a mental illness was associated with less preference to seek help from informal sources, whilst increased preference to seek help from mental health professionals and services and less personal and perceived stigma. These findings re-emphasise the need to improve mental health literacy and reinforce the potential benefits recognition can have to individuals and the wider community in Singapore.
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