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PE.210 SCUBA, Fall 2006

Authors:

This course will thoroughly educate the successful student with the knowledge and skills necessary to be a certified beginning SCUBA diver. The prerequisite for the course is passing the MIT SCUBA swim test and demonstrating a "comfort level" in the water. At the end of the class, students will attempt to pass the certification exam to become certified divers. The class is taught in two parts each week: a classroom session and a pool session. The classroom sessions along with the reading material will provide the student with the knowledge necessary to pass the written exam. At the pool, the water skills are taught in progressions that build on the previous skills, making the difficult skills seem easy.

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Tauchmedizinische Beratung für Reisende – Was Sie und Ihre Patienten vor Antritt einer Tauchreise wi...

September 2009 · Flugmedizin · Tropenmedizin · Reisemedizin - FTR

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MODERN DECOMPRESSION ALGORITHMS: MODELS, COMPARISONS, AND STATISTICS

B. R. Wienke

The physics, biology, engineering, physiology, medicine, and chemistry of diving center on pressure, and pressure changes. The average individual is subjected to atmospheric pressure swings of 3% at sea level, as much as 20% a mile in elevation, more at higher altitudes, and all usually over time spans of hours to days. Divers and their equipment can experience compressions and decompressions ... [Show full abstract] orders of magnitude greater, and within considerably shorter time scales. While the effects of pressure change are readily quantified in physics, chemistry, and engineering applications, the physiology, medicine, and biology of pressure changes in living systems are much more complicated. Increases in pressure with increasing depth impose many of the limitations in diving, applying equally well to the design of equipment. Early divers relied on their breathholding ability, while later divers used diving bells. Surface supplied air and SCUBA are rather recent innovations. With increasing exposure times and depths, divers encountered physiological and medical problems constraing activity, with decompression illness (DCI) perhaps the most noteworthy. By the 1880s, bubbles were noted in animals subjected to pressure reduction. By the 1900s, bubbles were postulated as the cause of DCI in divers and caisson workers. Within that postulate and drven by the need to optimize diver and aviator safety and time, decompression modeling has consolidated early rudimentary schedules into present more sophisticated tables and models. As basic knowledge and understanding of the biophysical effects of pressure change increase, so will the validity, reliability, and range of applicable models and algorithms used to stage diver ascents.

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Association between PFO and neurological decompression illness

February 2009 · Italian Journal of Pediatrics

Sir, Greco et al. described a case of a 12-year-old girl who presented symptoms of stroke after diving into the sea [1]. An ischemic lesion in the lenticular nucleus, in the posterior limb of internal capsula and in the caudate nucleus of the right hemisphere was found at a Diffusion Weighted Imaging. No abnormality of coagulation parameters was revealed. Surprisingly, there is no mention of ... [Show full abstract] investigation of congenital heart disease, which is recognised as a major cause of stroke in children [2]. Persistence of patent foramen ovale (PFO) is present in up to 25% of general population. Under normal circumstances, this is of little relevance as the left atrial pressure is higher than that of the right and the PFO is functionally closed most of the time. However, during coughing, sneezing, diving, and other conditions of increased endothoracic pressure, the PFO can open allowing potential for right-to-left shunt. This opens the cerebral circulation to the systemic venous circulation and has been implicated in the pathogenesis of stroke [3]. In adults, the presence of PFO is associated with cryptogenic stroke [4]. It is not known whether children with such condition have a similar increase in PFO, but a causal link has been suggested [5]. SCUBA diving is popular between adolescents. There is an association between PFO and neurological decompression illness, the onset of which is soon after surfacing. Divers with this type of decompression illness have a much higher prevalence of significant right-to-left shunt than do controls [6]. An increased prevalence of brain lesions has also been reported in divers, with a right-to-left shunt present in those with multiple brain lesions [7]. Although rare, cryptogenic stroke in childhood is devastating, and investigation of PFO-associated right-to-left shunt is largely warranted in such condition [8].

Article

Reduced gradient bubble model

December 1990 · International Journal of Bio-Medical Computing

B. R. Wienke

An approach to decompression modeling, the reduced gradient bubble model (RGBM), is developed from the critical phase hypothesis. The phase limit is introduced, extended, and applied within bubble-nucleation theory proposed by Yount. Much is different in the RGBM algorithm, on both theoretical and applied sides, with a focus on permissible bubble excesses rather than just dissolved gas buildup, ... [Show full abstract] something of a departure from traditional models. Overall, the approach is conservative, with changes in parameter settings affording flexibility. Marginal profiles permitted by tables and meters are restricted by the bubble algorithm. Highlighted features of the conservative algorithm include: (1) reduced no-stop time limits from the varying-permeability model (VPM); (2) short safety stops (or shallow swimming ascents) in the 10-20 feet of sea water (fsw) zone; (3) ascent and descent rates of 60 fsw/min, or slower; (4) restricted repetitive exposures, particularly beyond 100 fsw, based on reduced permissible bubble excess; (5) restricted spike (shallow-to-deep) exposures based on excitation of additional micronuclei; (6) restricted multi-day activity based on regeneration of micronuclei; (7) consistent treatment of altitude diving within model framework; (8) algorithm linked to bubble-nucleation theory and experiment. Coupled to medical reports about the long term effects of breathing pressurized gases and shortcomings in dissolved gas models, conservative modeling seems prudent.

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Raynaud's phenomenon and diving

January 2017 · Revista de la Asociacion Espanola de Especialistas en Medicina del Trabajo

Raynaud´s phenomenon is characterised by episodic vasospasm of the fingers and toes typically precipitated by exposure to cold or when you are feeling stressed. When this happens, blood can´t get to the surface of the skin and the affected areas turn white and blue. We present a case report of primary Raynaud´s phenomenon during a training scuba diving. A healthy 24-year-old Caucasian male made a ... [Show full abstract] swimming exercise on surface. After this activity he noted pain and skin discoloration on both legs and arms. A review of the posible diagnoses and fitness to dive in presented herein.

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Northill Air Lung Fourth Field Test (Navy Experimental Diving Unit Report ER-8-57)

August 1956

C. J. Leyden

This report covers the evaluation of the Northill Air-Lung Regulator to determine the suitability of the apparatus for use in the Naval Service to depths of 200 feet at work rates equivalent to 0.85 knot swimming. For the description of the demand regulator in detail, see Evaluation Report 3-57. The regulator was tested objectively by breathing machine runs and subjectively by depth swimming ... [Show full abstract] runs, with instrumentation for respiratory pressure, respiratory minute volume, and breathing rate. Subjective swimming pool tests covered in Evaluation Report 3-57 were not repeated here. Breathing machine runs are summarized as recording tape excerpts of peak respiratory pressure versus depth and cylinder pressure. The subjective depth swimming runs are summarized as graphs of peak respiratory pressure, respiratory minute volume, and respiratory rate against time, cylinder pressure, and depth. The results are discussed constructively and lead to specific conclusions about the apparatus and its suitability for use in the Naval Service.

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Behandlung akuter kochleovestibul�rer Sch�digungen nach dem Tauchen

January 2004 · HNO

Background There has been a steady increase of recreational scuba divers in the last years. The majority of diving associated diseases involve otorhinolaryngology, the most important of which are cochleovestibular dysfunctions as these can lead to permanent inner ear failure. Material and methods We discuss the origin and clinical symptoms, as well as the therapy, of both inner ear barotrauma and ... [Show full abstract] inner ear decompression illness. Our own experiences are considered together with a review of the literature from the last decade. Results Inner ear decompression illness seems to be a relatively common diving associated incident and is not as rare as previously thought. Discussion Hyperbaric oxygen therapy is the treatment of choice for patients with inner ear decompression sickness, but is contraindicated in patients with inner ear barotrauma. As long as an inner ear decompression illness can not be ruled out, we suggest that every patient should be treated using hyperbaric oxygen therapy but only after bilateral paracentesis.

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Securables, Permissions, and Auditing

January 2008

Joseph Sack

In the previous chapter, I discussed principals, which are security accounts that can access SQL Server. In this chapter, I’ll discuss and demonstrate securables and permissions. Securables are resources that SQL Server controls access to through permissions. Securables in SQL Server fall into three nested hierarchical scopes. The top level of the hierarchy is the server scope, which contains ... [Show full abstract] logins, databases, and endpoints. The database scope, which is contained within the server scope, controls securables such as database users, roles, certificates, and schemas. The third and innermost scope is the schema scope, which controls securables such as the schema itself, and objects within the schema such as tables, views, functions, and procedures.

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Effect of In-water SCUBA Diving Activities on Response Time in Recreational Divers

March 2017 · International Journal of Aquatic Research and Education

The purpose of this study was to examine the relationship between the performance of in-water scuba diving training activities and simple motor response time. Twenty-four students enrolled in a scuba course had their motor response times measured before and after a one hour training session. Pre-and post-dive response times were measured using an iPad application. Additionally, students were ... [Show full abstract] asked to complete a dive history questionnaire to determine their diving experience and health history. Statistical analysis indicated a significant training effect on response time in the recreational scuba divers F (1.00, 23.00) p =.033. The results of this study suggest that basic in-water scuba training activities may improve one's ability to elicit quicker movement responses and lead to faster cognitive processing.

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1000 Foot Unmanned Certification Dive in Number 5 Chamber Complex.

January 1972

RD Brewer

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Subjective Evaluation of Scott Aviation Corp's Constant Flow Shallow Water Diving Unit

February 1957

George Haslip

This evaluation was made to determine the suitability of a constant flow shallow water mask as a possible substitute for, or replacement of the U.S. Navy Standard shallow water mask. This constant flow shallow water diving mask was evaluated subjectively by pressure tank dives, and the comments are a composite of the subject's opinions. The results are discussed and lead to recommendations ... [Show full abstract] concerning modifications required prior to certification as recommended for naval service. The mechanical workmanship of the evaluated constant flow shallow water diving mask is quite good, the design is simple, the maintenance is easy and it has a greater field of vision than the present mask.

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Physical Fitness Requirements for Explosive Ordnance Disposal Divers

October 1998

The purpose of this study was to explore relationships between performance of EOD job tasks and physical fitness measures and to determine minimum physical fitness scores, to serve as standards for EOD personnel. Subjects were 47 active-duty EOD personnel. Mean age was 31.8 +-5.8 years; stature, 177.4 +-5.8 cm; body mass, 81.1 +-10.9 kg; and body fat content, 17.1 +-5.3%. Physical fitness ... [Show full abstract] attributes measured were: Sit-reach distance, push-ups in 2 min, curl-ups in 2 min, pull-ups, long jump, 1.5-mile run, 3.0-mile run, 500-yd pool swim, and 1,000-yd ocean swim. Performance on 4 job task simulations was measured as time for task completion: (1) carrying diving equipment; (2) lifting twin-80 SCUBA tanks; (3) 500-yd bay surface swim; and (4)100-yd rescue swim. Fat-free mass was a significant predictor (p <0.05) of performance on all of the job task simulations. Body mass was a significant predictor of performance on the SCUBA tank lift, bay swim time, and rescue swim time. Stature was related significantly to equipment carry time and bay swim time. The PRT items were, in general, poor predictors of performance on the job task simulations. The only significant prediction was push-ups for performance on the bay swim and rescue swim.