4,854 research outputs found
Florida's West Coast inlets: shoreline effects and recommended action
This report responds to the 1986 Beaches Bill which, in recognition of the
potential deleterious impact on Florida's beaches of inlets modified for navigation,
mandated a study of those inlets with identification of recommended action to reduce
the impacts. This report addresses west Coast inlets; East Coast inlets are the
subject of a companion report.
There are 37 inlets along that portion of Florida's West Coast commencing from
Pensacola Bay Entrance to Caxambas Pass at the south end of Marco Island. Compared to
those on the East Coast, most West Coast inlets have not had the deleterious effects
on the adjacent beaches, yet all modified inlets without proper management have the
potential of impacting unfavorably on the adjacent shorelines. Moreover, at present
there is interest in opening three West Coast entrances which either have been open
in the past (Midnight Pass) or which have opened occasionally (Navarre Pass and
Entrance to Phillips Lake).
A review of inlets in their natural condition demonstrates the presence of a
shallow broad outer bar across which the longshore transport Occurs. These shallow
and shifting bar features were unsuitable for navigation which in many cases has led
to the deepening of the channels and fixing with one or two jetty structures. Inlets in this modified state along with inappropriate maintenance practices have the
potential of placing great ero$ional stress along the adjacent beaches. Moreover.
channel dredging can reduce wave sheltering of the shoreline by ebb tidal shoals and
alter the equilibrium of the affected shoreline segments. The ultimate in poor sand
management practice is the placement of good quality beach sand in water depths too
great for the sand to reenter the longshore system under natural forces; depths of 12
ft. or less are considered appropriate for Florida in order to maintain the sand in
the system.
With the interference of the nearshore sediment transport processes by inlets
modified for navigation, if the adjacent beaches are to be stabilized there must be
an active monitoring program with commitment to placement of dredged material of
beach quality on shoreline segments of documented need. Several East Coast inlets
have such transfer facilities; however. the quantities of sand transferred should be
increased. Although an evolution and improvement in the technical capability to
manage sand resources in the vicinity of inlets is expected, an adequate capability
exists today and a concerted program should be made to commence a scheduled
implementation of this capability at those entrances causing greatest erosional
stress on the adjacent shorelines.
A brief summary review for each of the 37 West Coast inlets is presented
including: a scaled aerial photograph, brief historical information, several items
related to sediment losses at each inlet and special characteristics relevant to
State responsibilities. For each inlet, where appropriate, the above infor~tion is
utilized to develop a recommenced action. (PDF has 101 pages.
Barrier island erosion and overwash study -- effect of seawalls. Volume 2
This is the second of a pair of reports documenting the effects of storms on beach systems
including the presence of seawalls. With the aim of simulating the effects of overwash on
barrier islands with seawalls and characterizing their response, a series of eight experiments
was conducted at the Coastal Engineering Laboratory of the University of Florida. The barrier
island was simulated by a 400 feet wide horizontal crest and an initially uniform mildly-sloped
(1:19) beach. The effects of positioning the seawall at two different locations as well as the effects
of various storm surge levels and accompanying overtopping were investigated. Experiments
were conducted with both regular and irregular storm waves. With the seawall located at the
slope break between the crest and the sloping beach of the barrier island, and the crest of the
seawall just submerged in sand, the effects on the sediment transport process were found to be
minimal. For the same position of the seawall but with the crest of the seawall raised above the
surrounding ground level, overtopping caused washover of sand indicating substantial transport
in suspension. Increased levels of overtopping tended to accentuate bed profile changes but
supress bar formation (as did irregular waves). Positioning the seawall at the Mean Sea Level
shoreline caused significant scour both immediately landward as well as immediately seaward
of the seawall. A prominent scour trough developed further seaward. The longshore bar was
highly three-dimensional. It appears that seawalls need to be located adequately landward of the
shoreline to discharge their function effectively without adverse effect to the beach. In addition,
concerns for safety warrant the presence of an adequate buffer-zone between the seawall and
the upland property. (61 pp.
Florida's East Coast Inlets: shoreline effects and recommended action
A brief summary review for each of the 19 inlets on Florida's East Coast is presented including:
a scaled aerial photograph, brief historical information, several items
related to sediment losses at each inlet and special characteristics relevant
to State responsibilities. For each inlet the above information is utilized to develop a recommended action, usually in the form of periodic sand transfer
quantities. (PDF contains 67 pages
Ontogenies of Phototactic Behavior and Metamorphic Competence in Larvae of Three Species of \u3cem\u3eBugula\u3c/em\u3e (Bryozoa)
The free swimming larvae of many marine invertebrates actively respond to light. Light cues can be used to regulate position in the water column and to facilitate encountering sites suitable for metamorphosis. We examined the ontogeny of larval phototaxis and the ontogeny of metamorphic competency in larvae from three congeneric species of bryozoans. Larvae of Bugula neritina are positively phototactic on emergence from the brood chamber, whereas larvae of B. simplex and B. stolonifera appear initially photoneutral when populations of larvae are examined. Larvae of all three species become photonegative with time. Temporally coincident with this change to negative phototaxis is an increase in the competency of larvae to initiate metamorphosis. This observation suggests that these events are either physiologically linked or co-occurring, but independent developmental processes. We tested these hypotheses by artificially changing the sign of phototaxis from positive to negative using 10-5 M bath- applied 5-hydroxytryptamine (5HT) in larvae of B. neritina that were swimming for 1 h. Larvae that were photopositive and 1-h-old did not metamorphose at levels significantly different from larvae that were 1-h-old and treated with 5HT (i.e., young, photonegative larvae). Additionally, photopositive larvae which were swimming for 4 h initiated metamorphosis at rates nearly identical to photonegative larvae of the same age. Our data document that in larvae of B. neritina the changes in sign of phototaxis and levels of metamorphic competency are independent developmental events that occur in temporal coincidence. The concurrent timing of these two pathways may have been synchronized through selective processes resulting in a tight coupling between arrival at potentially suitable sites for metamorphosis and ability to respond to metamorphic cues
Comparison of the Effects of Ice and 3.5% Menthol Gel on Blood Flow and Muscle Strength of the Lower Arm
Context: Soft-tissue injuries are commonly treated with ice or menthol gels. Few studies have compared the effects of these treatments on blood flow and muscle strength. Objective: To compare blood flow and muscle strength in the forearm after an application of ice or menthol gel or no treatment. Design: Repeated measures design in which blood-flow and muscle-strength data were collected from subjects under 3 treatment conditions. Setting: Exercise physiology laboratory. Participants: 17 healthy adults with no impediment to the blood flow or strength in their right arm, recruited through word of mouth. Intervention: Three separate treatment conditions were randomly applied topically to the right forearm: no treatment, 0.5 kg of ice, or 3.5 mL of 3.5% menthol gel. To avoid injury ice was only applied for 20 min. Main Outcome Measures: At each data-collection session blood flow (mL/min) of the right radial artery was determined at baseline before any treatment and then at 5, 10, 15, and 20 min after treatment using Doppler ultrasound. Muscle strength was assessed as maximum isokinetic flexion and extension of the wrist at 30°/s 20, 25, and 30 min after treatment. Results: The menthol gel reduced (–42%, P \u3c .05) blood flow in the radial artery 5 min after application but not at 10, 15, or 20 min after application. Ice reduced (–48%, P \u3c .05) blood flow in the radial artery only after 20 min of application. After 15 min of the control condition blood flow increased (83%, P \u3c .05) from baseline measures. After the removal of ice, wrist-extension strength did not increase per repeated strength assessment as it did during the control condition (9–11%, P \u3c .05) and menthol-gel intervention (8%, P \u3c .05). Conclusions: Menthol has a fast-acting, short-lived effect of reducing blood flow. Ice reduces blood flow after a prolonged duration. Muscle strength appears to be inhibited after ice application
Fit Into College II: Physical Activity and Nutrition Behavior Effectiveness and Programming Recommendations
Purpose: To determine whether residency (living on campus versus off campus) was related to the effects of Fit into College on students’ health behaviors, and to understand interns’ perceptions of their roles in mentoring their trainees.
Design: Pre-experimental, one-group, pretest-posttest design and a posttest focus group interview.
Setting: University-offered health and internship courses.
Subjects: Twenty-four students (trainees) participated in the intervention, nine of whom lived on campus. Five student-interns served as their mentors.
Intervention: Fit into College was a 14-week intervention in which trainees teamed up with an intern to improve and/or maintain healthy nutrition and physical activity behaviors.
Measures: Trainees’ nutrition and physical activity behaviors and perceptions were quantitatively assessed through surveys at preintervention and postintervention. Interns’ mentoring perceptions were qualitatively assessed through a focus group interview after the intervention.
Analysis: Two-factor repeated measure ANOVAs and qualitative theme identification.
Results: Regardless of their residency location, the trainees’ perceptions of the health benefits of eating fruits and vegetables improved during the intervention. However, for trainees living on campus, the intervention was not effective in increasing the number of fruits and vegetables consumed or the planning for food preparation. The interns perceived that they did not have adequate access to healthy foods, the knowledge or skills to prepare healthy foods, or the competency to teach food preparation strategies to their trainees. For trainees living on campus, the intervention was more effective in decreasing perceived exercise barriers than trainees living off campus.
Conclusion: Future iterations of Fit into College may focus on 1) improving college students’ planning and preparation of healthy foods, 2) segmenting trainees into more homogeneous groups for the interns to tailor their areas of expertise (campus vs. off-campus and/or freshman vs. upperclass students), and 3) collaborating with university-partners to improve environmental conditions to promote physical activity and healthy nutrition
Barrier island erosion and overwash study - volume 1
This is the first of a pair of reports documenting the effects of storms on barrier island systems.
The present report (Volume 1) investigates storm effects on natural island conditions whereas
Volume 2 addresses the effects of seawalls. With the aim of simulating the effects of overwash
on barrier islands and characterizing their response, a series of nine experiments was conducted
at the Coastal Engineering Laboratory of the University of Florida. The barrier island was
simulated by a 400 feet wide (prototype units) horizontal crest and an initially planar (1:19)
beach. The effects of various storm surge levels and accompanying overtopping were investigated.
Experiments were conducted with both regular and irregular storm waves. Regular
waves without overtopping caused the formation of a substantial berm in the swash zone and a
prominent longshore bar offshore. Increasing degrees of overtopping resulted in substantial loss
of sand from the barrier island system. The longshore bar was considerably more subtle for the
highest water level tested (11.5 ft. above mean sea level). Simulation of a storm-surge hydrograph
with rising and falling water levels indicated that the presence of the bar tends to occur
only during a relatively steady or slowly changing water level. The experiments with irregular
waves were conducted with reasonably similar wave heights and carrier periods as those with
regular waves. The major difference was in the characteristics of the longshore bar response. In
comparison with cases with regular waves, the bar was less distinct without overtopping, subtle
with minimal overtopping and absent in cases with substantial overtopping. These experiments
seem to indicate that offshore bars are simply break-point bars which require a fairly steady
break-point and undertow (return of mass transport) for optimal formation. (Document has 84 pages.
Weed Control in Lawns and Other Turf
Guide to weed control in lawns and other turf discusses methods of weed control, time of application, calibration of sprayers, dry spreaders, control of common weeds, and cleaning the sprayer
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