scholarly journals SWASH ZONE BED LEVEL CHANGES AND SEDIMENT ENTRAINMENT AT THE SURF-SWASH BOUNDARY

2011 ◽  
Vol 1 (32) ◽  
pp. 28
Author(s):  
Stine Gro Jensen ◽  
Troels Aagaard ◽  
Tom E. Baldock
Keyword(s):  
Sediment Load ◽  
Outer Boundary ◽  
Water Levels ◽  
Swash Zone ◽  
Detailed Data ◽  
Perfect Agreement ◽  
Pressure Transducers ◽  
Run Up ◽  
Minor Disagreement

In the process of estimating the effect of sediment advection into the swash zone from bore collapse, a method in which buried self-logging pressure transducers are used to measure bed level changes in the swash zone, over a timeframe of several hours to inter-swash level, has been tested against bed level changes obtained from rod measurements. The test shows perfect agreement in the upper and mid swash while minor disagreement (1 cm) in the lower swash occurred. The deployment of self-logging pressure transducers has proven to be an accurate, easy and flexible method to obtain highly detailed data on water levels and bed elevations in the swash zone. Water levels derived from the pressure transducers show that swash zone characteristics vary from the upper to lower swash. Using pressure transducers in the swash zone coupled with measurements of the hydrodynamics and sediment concentrations at the outer boundary of the swash zone will improve the ability to explain the role of sediment advection from bore collapse. In relation to this, a method which consistently identify bores at the surf-swash boundary and quantifies the suspended sediment load carried by such bores prior to their collapse and run-up in the swash zone, is also presented.

Home Equity and Labor Income: The Role of Constrained Mobility

2020 ◽  
Author(s):  
Radhakrishnan Gopalan ◽  
Barton Hamilton ◽  
Ankit Kalda ◽  
David Sovich
Keyword(s):  
Law Enforcement ◽  
Labor Income ◽  
Detailed Data ◽  
Job Tenure ◽  
Home Equity ◽  
Employment Opportunities ◽  
Nonlinear Relation ◽  
Local Employment

Abstract Using detailed data for U.S. homeowners, we document a negative, nonlinear relation between the loan-to-value ratio (LTV) of homeowners' primary residence and their labor income. Consistent with high LTV individuals experiencing constrained mobility, we find stronger effects among subprime, liquidity-constrained individuals and those living in regions with limited alternative local employment opportunities and strict noncompete law enforcement. Though high LTV individuals are less likely to move across MSAs, they are more likely to change jobs without changing their residence. We find no effects among similar neighboring renters employed at the same firm and with a similar job tenure.

A comparison between the CS-TOF and the CTA/DSA for WEB device management

2021 ◽  
pp. 159101992110147
Author(s):  
Oktay Algin ◽  
Gokhan Yuce ◽  
Ural Koc ◽  
Gıyas Ayberk
Keyword(s):  
Mr Angiography ◽  
Three Dimensional ◽  
Morphological Parameters ◽  
Perfect Agreement ◽  
Device Management ◽  
Web Device ◽  
Sensing Time ◽  
The Web

Purpose There is no study on the role of three-dimensional compressed sensing time of flight MR angiography (3D-CS-TOF) in the management of the WEB device. We evaluated the efficacy of 3-tesla 3D-CS-TOF for the management and follow-up of the WEB device implantations. Materials and methods Seventy-three aneurysms of 69 patients treated with the WEB device were retrospectively examined. Morphological parameters and embolization results of the aneurysms were assessed and compared on 3D-CS-TOF, CTA, and DSA images. Results Occluded, neck remnant, and recurrent aneurysms were observed in 61 (83.6%), 7 (9.6%), and 5 (6.8%) aneurysms, respectively. Inter- and intra-reader agreement values related to aneurysm size measurements were perfect. Aneurysms size, age, and proximal vessel tortuosity were negatively correlated with the visibility of the aneurysms and parent vessels on 3D-CS-TOF images (p = 0.043; p = 0.032; p < 0.001, respectively). Subarachnoid hemorrhage and age are associated with 3D-CS-TOF artifacts (p = 0.031; p = 0.005, respectively). 3D-CS-TOF findings are in perfect agreement with DSA or CT angiography (CTA) results (p < 0.001). Conclusion According to our results, 3D-CS-TOF can be an easy, fast, and reliable alternative for the management or follow-up of WEB assisted embolization.

scholarly journals The role of the reef–dune system in coastal protection in Puerto Morelos (Mexico)

2018 ◽  
Vol 18 (4) ◽  
pp. 1247-1260 ◽  
Author(s):  
Gemma L. Franklin ◽  
Alec Torres-Freyermuth ◽  
Gabriela Medellin ◽  
María Eugenia Allende-Arandia ◽  
Christian M. Appendini
Keyword(s):  
Sand Dunes ◽  
Coastal Flooding ◽  
Water Levels ◽  
Coastal Protection ◽  
Dune System ◽  
Fore Reef ◽  
Extreme Water Levels ◽  
Reef Environments ◽  
Storm Impact

Abstract. Reefs and sand dunes are critical morphological features providing natural coastal protection. Reefs dissipate around 90 % of the incident wave energy through wave breaking, whereas sand dunes provide the final natural barrier against coastal flooding. The storm impact on coastal areas with these features depends on the relative elevation of the extreme water levels with respect to the sand dune morphology. However, despite the importance of barrier reefs and dunes in coastal protection, poor management practices have degraded these ecosystems, increasing their vulnerability to coastal flooding. The present study aims to theoretically investigate the role of the reef–dune system in coastal protection under current climatic conditions at Puerto Morelos, located in the Mexican Caribbean Sea, using a widely validated nonlinear non-hydrostatic numerical model (SWASH). Wave hindcast information, tidal level, and a measured beach profile of the reef–dune system in Puerto Morelos are employed to estimate extreme runup and the storm impact scale for current and theoretical scenarios. The numerical results show the importance of including the storm surge when predicting extreme water levels and also show that ecosystem degradation has important implications for coastal protection against storms with return periods of less than 10 years. The latter highlights the importance of conservation of the system as a mitigation measure to decrease coastal vulnerability and infrastructure losses in coastal areas in the short to medium term. Furthermore, the results are used to evaluate the applicability of runup parameterisations for beaches to reef environments. Numerical analysis of runup dynamics suggests that runup parameterisations for reef environments can be improved by including the fore reef slope. Therefore, future research to develop runup parameterisations incorporating reef geometry features (e.g. reef crest elevation, reef lagoon width, fore reef slope) is warranted.

scholarly journals Distance from Africa, not climate, explains within-population phenotypic diversity in humans

2008 ◽  
Vol 276 (1658) ◽  
pp. 809-814 ◽  
Author(s):  
Lia Betti ◽  
François Balloux ◽  
William Amos ◽  
Tsunehiko Hanihara ◽  
Andrea Manica
Keyword(s):  
Climatic Factors ◽  
Phenotypic Diversity ◽  
Morphological Diversity ◽  
Sub Saharan Africa ◽  
Relative Role ◽  
Morphometric Traits ◽  
Perfect Agreement ◽  
Skull Measurements ◽  
Sub Saharan

The relative importance of ancient demography and climate in determining worldwide patterns of human within-population phenotypic diversity is still open to debate. Several morphometric traits have been argued to be under selection by climatic factors, but it is unclear whether climate affects the global decline in morphological diversity with increasing geographical distance from sub-Saharan Africa. Using a large database of male and female skull measurements, we apply an explicit framework to quantify the relative role of climate and distance from Africa. We show that distance from sub-Saharan Africa is the sole determinant of human within-population phenotypic diversity, while climate plays no role. By selecting the most informative set of traits, it was possible to explain over half of the worldwide variation in phenotypic diversity. These results mirror those previously obtained for genetic markers and show that ‘bones and molecules’ are in perfect agreement for humans.

scholarly journals ASSESSMENT OF COASTAL VULNERABILITY BASED ON THE USE OF INTEGRATED LOW-COST MONITORING APPROACH AND BEACH MODELLING: TWO ITALIAN STUDY

2020 ◽  
pp. 13
Author(s):  
Renata Archetti ◽  
Maria Gabriella Gaeta ◽  
Fabio Addona ◽  
Leonardo Damiani ◽  
Alessandra Saponieri ◽  
...  
Keyword(s):  
Low Cost ◽  
Integrated Approach ◽  
Video Monitoring ◽  
Monitoring Systems ◽  
Swash Zone ◽  
Coastal Vulnerability ◽  
Italian Study ◽  
Shoreline Evolution ◽  
Low Costs ◽  
Run Up

The use of video-monitoring techniques is significantly increased due to the diffusion of high-resolution cameras at relatively low-costs and they are largely used to estimate the shoreline evolution and wave run-up, as important coastal state indicators to be monitored and predicted for the assessment of flooding and erosion risks. In this work, we present an integrated approach based on the results from the low-cost video monitoring systems and the numerical modeling chain by means of SWAN and XBeach to accurately simulate and predict the swash zone processes.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/nLGNneJzmIU

scholarly journals PRE- and POST-STORM LiDAR SURVEYS FOR ASSESSMENT OF IMPACT ON COASTAL EROSION

2019 ◽  
Vol XLII-3/W8 ◽  
pp. 261-266
Author(s):  
A.-L. Montreuil ◽  
M. Chen ◽  
A. Esquerré ◽  
R. Houthuys ◽  
R. Moelans ◽  
...  
Keyword(s):  
Management Practices ◽  
Morphological Changes ◽  
Storm Surges ◽  
High Water ◽  
Water Levels ◽  
Airborne Lidar ◽  
Coastline Change ◽  
The Mean ◽  
The Impact

<p><strong>Abstract.</strong> Sustainable management of the coastal resources requires a better understanding of the processes that drive coastline change. The coastline is a highly dynamic sea-terrestrial interface. It is affected by forcing factors such as water levels, waves, winds, and the highest and most severe changes occur during storm surges. Extreme storms are drivers responsible for rapid and sometimes dramatic changes of the coastline. The consequences of the impacts from these events entail a broad range of social, economic and natural resource considerations from threats to humans, infrastructure and habitats. This study investigates the impact of a severe storm on coastline response on a sandy multi-barred beach at the Belgian coast. Airborne LiDAR surveys acquired pre- and post-storm covering an area larger than 1 km<sup>2</sup> were analyzed and reproducible monitoring solutions adapted to assess beach morphological changes were applied. Results indicated that the coast retreated by a maximum of 14.7 m where the embryo dunes in front of the fixed dunes were vanished and the foredune undercut. Storm surge and wave attacks were probably the most energetic there. However, the response of the coastline proxies associated with the mean high water line (MHW) and dunetoe (DuneT) was spatially variable. Based on the extracted beach features, good correlations (r>0.73) were found between coastline, berm and inner intertidal bar morphology, while it was weak with the most seaward bars covered in the surveys. This highlights the role of the upper features on the beach to protect the coastline from storm erosion by reducing wave energy. The findings are of critical importance in improving our knowledge and forecasting of coastline response to storms, and also in its translation into management practices.</p>

scholarly journals Role of intertidal wetlands for tidal and storm tide attenuation along a confined estuary: a model study

2015 ◽  
Vol 3 (5) ◽  
pp. 3181-3224 ◽  
Author(s):  
S. Smolders ◽  
Y. Plancke ◽  
S. Ides ◽  
P. Meire ◽  
S. Temmerman
Keyword(s):  
Surface Area ◽  
Wave Attenuation ◽  
Spring Tide ◽  
Storm Surges ◽  
High Water ◽  
Water Levels ◽  
Storm Tide ◽  
Flood Risks ◽  
Model Study

Abstract. Coastal lowlands and estuaries are subjected to increasing flood risks during storm surges due to global and regional changes. Tidal wetlands are increasingly valued as effective natural buffers for storm surges by dissipating wave energy and providing flood water storage. While previous studies focused on flood wave attenuation within and behind wetlands, this study focuses on the effects of estuarine wetland properties on the attenuation of a storm tide that propagates along the length of an estuary. Wetland properties including elevation, surface area, and location within the estuary were investigated using a numerical model of the Scheldt estuary (Belgium, SW Netherlands). For a spring tide lower wetland elevations result in more attenuation of high water levels along the estuary, while for a higher storm tide higher elevations provide more attenuation compared to lower wetland elevations. For spring and storm tide a arger wetland surface area results in a better attenuation along the estuary up to a threshold wetland size for which larger wetlands do not further contribute to more attenuation. Finally a wetland of the same size and elevation, but located more upstream in the estuary, can store a larger proportion of the local flood volume and therefore has a larger attenuating effect on upstream high water levels. With this paper we aim to contribute towards a better understanding and wider implementation of ecosystem-based adaptation to increasing estuarine flood risks associated with storms.

Domestic Politics and the Motives of Emerging Donors: Evidence from Turkish Foreign Aid

2018 ◽  
Vol 71 (3) ◽  
pp. 614-627 ◽  
Author(s):  
Kerim Can Kavakli
Keyword(s):  
Foreign Aid ◽  
Domestic Politics ◽  
Humanitarian Aid ◽  
Detailed Data ◽  
Systematic Data ◽  
Emerging Donors ◽  
Different Types ◽  
Government Change ◽  
Trade Partners

Why do developing countries give foreign aid? Although emerging donors are gaining importance in development finance, lack of systematic data on their aid allocation limits our understanding of their motives. We address this gap using detailed data on a major new donor, Turkey, since 1992. We show that domestic politics has had a large impact on Turkey’s priorities in giving aid. Turkish aid used to be determined by international alignments and coethnicity, but after the Islamic AKP ( Adalet ve Kalkınma Partisi) took power, political ties lost importance. Turkey began to give more economic aid to trade partners and more humanitarian aid to Muslim nations. While this new focus on trade ties makes Turkey more similar to traditional donors, the growing role of cultural ties sets Turkey apart. The broader lesson of this study on Turkey is that government change can significantly influence the way emerging donors give aid and these changes can vary in predictable ways across different types of aid.

Egypt’s Plasticine Constitution

2021 ◽  
pp. 220-264
Author(s):  
Sherif Elgebeily
Keyword(s):  
Presidential Elections ◽  
Eligibility Criteria ◽  
National Elections ◽  
Democratic Quality ◽  
The Creation ◽  
Run Up ◽  
Democratic Principles ◽  
Constitutional Protections

On 26 March 2018, Egyptians overwhelmingly voted to elect incumbent Abdel Fattah El-Sisi to another term as their President in an election where the outcome was known in advance. Any genuine competition was eliminated from the pool of candidates through arrests, media attacks, and intimidation. This chapter examines how Egypt has reached point, the implications for its future, and the role that guaranteed electoral processes of the 2014 Egyptian Constitution played in diminishing the democratic quality of elections. The chapter paper takes a three-part approach to analysing the role of the constitution in the decline of democratic principles in the 2018 Egyptian Presidential elections. Firstly, it examines the constitutional protections of eligibility criteria that exist to support the presence of multi-party candidates in presidential elections, exploring how these were abused by the Sisi administration in the run-up to the elections. Secondly, the chapter analyses the creation of election governance bodies, notably the National Elections Committee (NEC), and its malleability in support of Sisi. Finally, the chapter examines the abuse of existing state machinery in the run-up to the elections and highlights how this has undermined authentic, free elections. The chapter links the 2018 elections to subsequent developments, including the 2019 constitutional referendum which broadened even further the Sisi administration’s control over the country at the expense of constitutional protections.

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