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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Rip currents in the UK : incident analysis, public awareness, and education

Woodward, Eleanor Molly January 2015 (has links)
Rip currents present a severe hazard to water users worldwide, resulting in over 100 drownings and thousands of lifeguard rescues annually. This thesis examines the demographics of who is effected by rip currents in the UK, what activity they are undertaking, when and where incidents occur, how much the public know, what people have experienced, and how best to educate them. Analysis of 7909 rip current lifeguard rescues (16777 people) across the UK between 2006-2013 highlighted the most at risk group, and subsequent target audience for education, to be male teenagers aged between 13-17 years old (n=2906, 17%). Geographically, the highest incidents occurred on the beaches in the Southwest of England (n=6911, 87%). Incidents mostly occurred outside of lifeguard flagged areas (n=4302, 54%) and mainly involved those using bodyboards (n=5290, 52%). Through the analysis of 407 public beach-based rip current and beach safety questionnaires, it was established that beach users have a poor understanding of rip currents (n=263, 65%) but a good perception of the beach safety flags (n=389, 96%). People with greater knowledge were typically educated by a lifeguard, enter the sea more frequently or have been caught in rip currents themselves. The experiences of 553 people caught in rip currents were analysed using an online questionnaire. The gender split was 69% male (n= 382) to 31% female (n= 171), indicating that males are caught in rip currents more than females. Swimming directly to shore against the rip followed an initial panic (n=108, 34%) for most people caught in a rip. Swimming parallel to the beach was the most remembered, advised, utilised, and promoted safety message. Respondents advocated the use of lifeguards to disseminate rip current safety messages. A new and unique rip current education programme was developed from the synthesis of these results. A lifeguard delivered a pilot programme to 185 teenagers in three schools and two community groups in the Southwest of England. This interactive pilot consisted of exercises using videos, photographs, news reports, and a swimming machine. Levels of rip current knowledge were evaluated before and after, and at regular intervals, to assess knowledge retention. The short-term effects after 3 months were positive, showing statistically significant (p < 0.0005) improvements in mean knowledge levels. This thesis provides a new contribution to the expanding field of social and behavioural rip current research. The development of a unique rip current education programme presents an alternative method for increasing public awareness, and supports the worldwide prevention of rip current incidents and fatalities.
2

Video monitoring devices on school buses: are they effective in reducing behavioral problems?

Slavinsky, Dennis A. 11 May 2006 (has links)
The purpose of this study was to evaluate the effectiveness of video monitoring devices (VMDs) in reducing incidents of student misbehavior on middle school buses. It was hypothesized that the presence of VMDs would decrease the frequency of behavioral problems encountered by school bus drivers, decrease the number of discipline referrals issued by the drivers, and improve the drivers’ perception of student behavior. The study utilized an experimental design with random assignment of drivers to treatment and control groups. These groups were formed from a population of 282 drivers who serve ten middle schools for Virginia Beach City Public Schools. In the summer of 1993, through a randomization procedure, VMDs were installed on 100 school buses to form the treatment group. The remaining 182 school buses did not receive installation and were designated as the control group. All drivers maintained a daily log of the number of discipline problems encountered on their routes for three 15-day intervals. Statistical analysis revealed a significantly lower number of problems in the treatment group. Secondary analysis indicated that the use of VMDs was ineffective on morning routes but effective on afternoon routes. Also, there was a significantly lower number of discipline problems in the treatment group regardless of the day of the week. As the drivers established rapport and control, both groups experienced a decline in the number of discipline problems throughout the experiment. The treatment group, however, recorded a significantly lower number of problems during each of the three 15-day intervals. This indicates that the students did not become desensitized to the presence of the VMD’s over the five-month experiment. At the conclusion of the study, drivers in the treatment group rated the behavior of their students more highly than the rating of students by drivers in the control group. A tally of the number of discipline referrals issued by the drivers revealed that the members of the treatment group experienced fewer severe disciplinary problems. Finally, multiple regression indicated that of all independent variables, group membership is the best predictor of a number of behavioral problems, discipline referrals issued, and driver perception of student behavior. / Ed. D.
3

Atmospheric and Ocean Conditions and Social Aspects Associated with Rip Current Drownings in the United States

Paxton, Charles Hugh 04 April 2014 (has links)
The purpose of this research is to provide a better understanding of the physical and social aspects of rip currents in ocean areas that will lead to better forecasts, better governmental policies in beach areas, and ultimately to save lives. A rip current is a nearshore circulation in which breaking waves run up onto the beach then retreat rapidly in deeper channels back toward the sea. Rip currents pose a significant threat to beachgoers and can pull even the strongest swimmers out to sea. The primary factors associated with rip current formation on unarmored beaches are variations in the local beach bathymetry, wind-generated longshore waves of varying height, and lower tidal stages. The rationale for this study is highlighted when rip current deaths are put in context with deaths from other weather related deaths. The average number of rip current deaths per year in the United States is 46 and in the year 2010 rip currents were responsible for 64 deaths which was higher than the deaths associated with lightning, tornadoes, hurricanes and the cold winter during the year. The methodology followed for this study includes a review of demographics from over 500 rip current drowning reports along the Atlantic Ocean, Pacific Ocean and Gulf of Mexico coasts of the United States from 1994-2012. This research indicates that tourists are often victims, and rescuers can become the victims. For each state or sub-state area where rip current drownings are prevalent, an analysis of social aspects, beach areas, and associated ocean and weather patterns was conducted using averaged wind and pressure fields over wave generation areas, buoy data, and tide data. It is important to understand the evolution of these drowning events and seek solutions to mitigate the problem.
4

Rip Current Formation and Beach Safety Implications for Several U.S. Atlantic Coast Beach Areas

Fallon, Kathleen Michelle 15 May 2017 (has links)
This dissertation combines seemingly different studies, which work together to describe the physical characteristics of rip current development and associated social implications at several locations. These fast-moving, concentrated flows of water travel offshore and can be found on any beach with sufficient wave action. Any event of increased wave steepness will erode a large quantity of sediment from the beach. The material deposited offshore eventually makes its way back; during this process, ocean water becomes trapped behind a shore-attached bar resulting in a ridge-and-runnel. These formations are seen at East Hampton, where rip-like currents form as concentrated water drains from the runnel through a breach in the ridge. Camera images from 2010-2016 captured ridge-and-runnel formations and the ensuing currents. These newly described rips behave similarly to bar-gaps; however, they are not directly related to wave action. Coastal scientists consider rip currents to be the number one hazard at most beaches. In Palm Beach County, two traditional rip types were studied: bar-gap and structurally-controlled. Lifeguard incident reports from 2011-2016 were used to correlate wind speeds and wave heights to rip related rescues at three beaches. This research was undertaken in an effort to determine under what conditions most beachgoers become caught in this hazard. Rip currents were seen to be the most dangerous to bathers on days with moderate wind and wave activity. The same beach states that lead to the strongest rips also tend to keep beachgoers from entering the ocean. A social survey at Miami Beach, from 2011 to 2012, quantified beachgoer’s rip knowledge and their recognition of hazards. A significant portion of the respondents showed insufficient knowledge, which indicated they are at-risk of being caught or drowning in a rip current. Frequent exposure to the beach, maturation, and residency were identified as the main contributors to one’s literacy whereas education was the only variable that influenced a beachgoer’s visual recognition of hazard. The information gathered by these surveys can aid in creating better rip current awareness campaigns targeted to demographics that were determined as the most at-risk. An understanding of the physical and social science of rip currents can mitigate the impact of these beach hazards.
5

Rip Current Generation, Flow Characteristics and Implications for Beach Safety in South Florida

Leatherman, Stephen B. 09 November 2018 (has links)
Rip currents are the most dangerous hazard at surf beaches. Rip currents in South Florida have previously not been studied. Beach profiles for three Florida beaches (Miami Beach, Lido Beach, Sarasota, and Pensacola Beach) and one Georgia beach (South Cumberland Island) were chosen for surveying because of their variable sand bar heights. Rip current hazard at each beach was assessed by lifeguard rip rescue and drowning statistics. A relationship was found between sand bar height, beach slope and rip current hazard. Rip current measurements in South Florida, which involved utilizing GPS drifters, laser rangefinder and drone-imaged fluorescent tracer dye, showed that the speed ranged from 0.1-0.5 m/s, which is fairly slow compared to such measurements undertaken in California and Australia. The effect of rip currents on swimmers was analyzed based on the drag force acting on swimmers and the power they generate to overcome the currents when swimming against them. The drag force and power increase quadratically and cubically, respectively, with the increase of rip current and swimming speeds. Hence, even rip currents of low velocity can be dangerous and swimming against the current should be avoided if possible. Strong rips in California have been shown to exhibit a circulatory pattern, which could bring a floater back to the safety of a shallow sand bar. Field measurements of rip currents in South Florida clearly defined the flow characteristics of a nearly straight-line current, sometimes deflected to the east-southeast. Therefore, the traditional approach of swimming left or right, parallel to the shore is the best escape strategy, but not against the longshore current if present. A logistic regression analysis was conducted to predict the occurrence of rip currents based on beach conditions. The logistic model showed that wave height, wave period and wind speed were statistically significant factors in rip generation. Rips were found to be most commonly generated by relatively small, non-threatening waves (e.g., 0.6 to 0.9m in height). These physical factors, along with social and safety considerations, pose a significant problem for coastal management.

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