549 research outputs found
Impacts of storm chronology on the morphological changes of the Formby beach and dune system, UK
Impacts of storm chronology within a storm cluster on beach/dune erosion are investigated by applying the state-of-the-art numerical model XBeach to the Sefton coast, northwest England. Six temporal storm clusters of different storm chronologies were formulated using three storms observed during the 2013/2014 winter. The storm power values of these three events nearly halve from the first to second event and from the second to third event. Cross-shore profile evolution was simulated in response to the tide, surge and wave forcing during these storms. The model was first calibrated against the available post-storm survey profiles. Cumulative impacts of beach/dune erosion during each storm cluster were simulated by using the post-storm profile of an event as the pre-storm profile for each subsequent event. For the largest event the water levels caused noticeable retreat of the dune toe due to the high water elevation. For the other events the greatest evolution occurs over the bar formations (erosion) and within the corresponding troughs (deposition) of the upper-beach profile. The sequence of events impacting the size of this ridge–runnel feature is important as it consequently changes the resilience of the system to the most extreme event that causes dune retreat. The highest erosion during each single storm event was always observed when that storm initialised the storm cluster. The most severe storm always resulted in the most erosion during each cluster, no matter when it occurred within the chronology, although the erosion volume due to this storm was reduced when it was not the primary event. The greatest cumulative cluster erosion occurred with increasing storm severity; however, the variability in cumulative cluster impact over a beach/dune cross section due to storm chronology is minimal. Initial storm impact can act to enhance or reduce the system resilience to subsequent impact, but overall the cumulative impact is controlled by the magnitude and number of the storms. This model application provides inter-survey information about morphological response to repeated storm impact. This will inform local managers of the potential beach response and dune vulnerability to variable storm configurations
Morphodynamic evolution of an estuary inlet
This paper presents the application of a morphodynamic model based on 2D reduced-physics principles to
investigate morphology change of a complex estuary inlet system in the United Kingdom. The model
combines a simple governing equation with a set of measured bathymetry data in order to model
morphology change. The modelling method suggests that this simplified approach is able to recognise
principal medium term morphodynamic trends in the estuary. However, the length and quality of the
estuary bathymetry data set limits the applicability of the model to inter-annual scale
Two-dimensional reduced-physics model to describe historic morphodynamic behaviour of an estuary inlet
Understanding medium to long term morphodynamic change is important for sustainable coastal and estuary management. This paper analyses morphodynamic change of a complex estuary inlet which is subjected to multiple environmental drivers and proposes a reduced physics model to explain the historic medium term morphodynamic change of the inlet. The analysis shows that even though the estuary inlet undergoes multiscale morphological change, the changes that take place over a timescale of several years are more significant and important. The reduced physics model suggests that this simplified modelling approach is able to recognise principal historic morphodynamic trends in the estuary. However, the length and quality of the inlet bathymetry data set limits the applicability of the models and the quality of model outputs
Range Extension and Vocalisation of Endangered Shrub Frog, Pseudophilautus zorro (Amphibia: Rachophoridae) in Sri Lanka
Gannoruwa shrub frog, Pseudophilautus zorro, is an endemic species known only from four locations in and around Kandy, Gannoruwa forest, home gardens in Triverton estate, Hanthana and Udawaththakele forest reserves. Despite their cryptic nature calling males are conspicuous once identified their vocalisation. Hence, we describe their vocalisation and acoustic characters. We recorded P. zorro from Hanthana (80.6141° E, 7.2497° N; 700 m a.s.l.) and measured six common call characters of 92 calls from four males. We identified four call types based on wave form structure and spectrogram. Type 1 calls were the most frequently emitted call type (93% of 518 calls recorded) having the average call duration 5.1±1.2 mili-seconds. Vocalising frequency of the species ranged between 3,100 Hz and 3,600 Hz. During our field excursions in 2014-2017, we heard similar vocalisation in two sites well away from its known range, Katugasthota (80.6199° E, 7.3302° N; 470 m a.s.l) and Ovilikanda (80.5926° E, 7.4538° E; 470 m a.s.l). We confirm the identity as P. zorro using the morphological characters. Again, on 18th September, 2014 we sighted the species during an excursion to Kukulamalpotha (80.7819° E, 7.5527° N; 460 m a.s.l) in Knuckles reserve. Since the site was very far from the known range of P. zorro, we obtained toe tips from two individuals and confirm their identity genetically by having 0% uncorrected pairwise genetic distance for 16S gene fragment (~510 bp). With three new found locations their Extent of Occurrence and Area of Occupancy has been increased by 14 times (from 20 km2 to 291 km2) and by 2 times (from 16 km2 to 28 km2) respectively. New found populations considerably expanded the species-range and the knowledge of their vocalisation can further use to explore new populations. This study confirms that P. zorro is not restricted as previously thought.Keywords: New population, Bioacoustics, Shrub frogs, Extent of occurrenc
A new perspective on meso-scale shoreline dynamics through data-driven analysis
The twin ambits of climate change and coastal development have raised public awareness of shoreline management. Simultaneously, they have highlighted a gap in our understanding of sediment transport and morphodynamic processes at time and space scales appropriate for shoreline management purposes. Here, we analyse an exceptional set of beach surveys gathered over a period of twenty-two years along the Suffolk coast, eastern UK, that extends over approximately 80 km to investigate the meso-scale shoreline variations. The surveys have been made biannually along fixed transects spaced at approximately 1 km intervals as part of a strategic monitoring exercise undertaken by the coastal authorities to assist in shoreline management planning. Changes in beach volume, foreshore slope and shoreline position have been computed to investigate both spatial and temporal changes. The analysis reveals some distinct responses to the physical processes of tides and waves, anthropogenic interventions and geological controls. Neither a clear relationship between the presence of sea defences and beach response nor an ordered regional-scale shoreline movement are evident. Temporal variations in beach volumes and position provide a similarly complex picture with recessionary, accretionary and stable behaviour all apparent within the study site. There is evidence of quasi-cyclic behaviour at some locations as well as a reduction in variability over time-scales beyond approximately five years
Characterization of self compacting concrete in terms of bingham constants
The purpose of this experimental work is to determine the domain of the Bingham constants within which a concrete mix possesses self-compactability. Flow characteristics or the rheological characteristics of concrete were expressed by using the Bingham model. Yield shear stress and the plastic viscosity are the two flow properties included in the Bingham model. A range of the combinations of yield shear stress and plastic viscosity was identified within which the concrete is likely to be self-compactable.
To determine the self-compactability of a concrete three index properties were determined by experiments. Those three properties are the filling ability, passing ability and the segregation resistance. To measure the filling ability, slump flow by Abram’s cone, T50cm slump flow time and V funnel test were used. To measure the passing ability, J ring test was used. V funnel at T5min test was used to test the resistance to segregation. Self-compactability was judged by comparing the results with the acceptable regions given in the EFNARC publications. Yield shear stress and the plastic viscosity were calculated by using the rotational speed and the applied torque on the concrete which were measured by a coaxial type cohesiometer.
The analysis of data by statistical procedures led to the charts showing variations of the workability indices with the water powder ratio and the superplasticizer dosage for different water cement ratios. Those charts are useful when proportioning self-compacting concrete mixes
OTUB1 inhibits the ubiquitination and degradation of FOXM1 in breast cancer and epirubicin resistance
The forkhead transcription factor FOXM1 has a key role in DNA damage response, and its deregulated overexpression is associated with genotoxic drug resistance in breast cancer. However, little is known about the posttranslational mechanisms by which FOXM1 expression is regulated by genotoxic agents and how they are deregulated in resistant cells. Initial co-immunoprecipitation studies verified previous proteomic analysis finding that the OTUB1 is a novel FOXM1-interacting protein. Western blot analysis showed that both OTUB1 and FOXM1 expression reduced upon genotoxic agent treatment in MCF-7 cells, but remained relatively constant in resistant cells. FOXM1 expression reduced upon OTUB1 depletion by siRNA and increased with OTUB1 overexpression in MCF-7 cells, arguing that OTUB1 positively regulates FOXM1 expression. In agreement, co-immunoprecipitation experiments demonstrated that FOXM1 expression is associated with OTUB1 binding but inversely correlates with conjugation to the protein degradation-associated Lys-48-linked ubiquitin-chains. Overexpression of wild-type (WT) OTUB1, but not the OTUB1(C91S) mutant, disrupted the formation of Lys48-linked ubiquitin-conjugates on FOXM1. Importantly, knockdown of OTUB1 by siRNA resulted in an increase in turnover of FOXM1 in MCF-7 cells treated with the protein synthesis inhibitor cycloheximide, whereas overexpression of WT OTUB1, but not the OTUB1(C91S) mutant, significantly enhances the half-life of FOXM1. In addition, proliferative and clonogenic assays also show that OTUB1 can enhance the proliferative rate and epirubicin resistance through targeting FOXM1, as OTUB1 has little effect on FOXM1-deficient cells. The physiological relevance of the regulation of FOXM1 by OTUB1 is further underscored by the significant correlations between FOXM1 and OTUB1 expression in breast cancer patient samples. Cox-regression survival analysis indicates that OTUB1 overexpression is linked to poorer outcome in particular in patients treated with chemotherapy. Collectively, these data suggest that OTUB1 limits the ubiquitination and degradation of FOXM1 in breast cancer and has a key role in genotoxic agent resistance
Large scale three-dimensional modelling for wave and tidal energy resource and environmental impact : methodologies for quantifying acceptable thresholds for sustainable exploitation
We describe a modelling project to estimate the potential effects of wave & tidal stream renewables on the marine environment. • Realistic generic devices to be used by those without access to the technical details available to developers are described. • Results show largely local sea bed effects at the level of the currently proposed renewables developments in our study area. • Large scale 3D modelling is critical to quantify the direct, indirect and cumulative effects of renewable energy extraction. • This is critical to comply with planning & environmental impact assessment regulations and achieve Good Environmental Status
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