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Sample records for aerobic dive limit

  1. Diving behaviour, dive cycles and aerobic dive limit in the platypus Ornithorhynchus anatinus.

    PubMed

    Bethge, Philip; Munks, Sarah; Otley, Helen; Nicol, Stewart

    2003-12-01

    We investigated the diving behaviour, the time allocation of the dive cycle and the behavioural aerobic dive limit (ADL) of platypuses (Ornithorhynchus anatinus) living at a sub-alpine Tasmanian lake. Individual platypuses were equipped with combined data logger-transmitter packages measuring dive depth. Mean dive duration was 31.3 s with 72% of all dives lasting between 18 and 40 s. Mean surface duration was 10.1 s. Mean dive depth was 1.28 m with a maximum of 8.77 m. Platypuses performed up to 1600 dives per foraging trip with a mean of 75 dives per hour. ADL was estimated by consideration of post-dive surface intervals vs. dive durations. Only 15% of all dives were found to exceed the estimated ADL of 40 s, indicating mainly aerobic diving in the species. Foraging platypuses followed a model of optimised recovery time, the optimal breathing theory. Total bottom duration or total foraging duration per day is proposed as a useful indicator of foraging efficiency and hence habitat quality in the species. PMID:14667845

  2. Aerobic dive limit does not decline in an aging pinniped.

    PubMed

    Hindle, Allyson G; Mellish, Jo-Ann E; Horning, Markus

    2011-11-01

    Apneustic hunters such as diving mammals exploit body oxygen stores while submerged; therefore, any decline in oxygen handling at advanced life stages could critically impair foraging ability. We calculated the aerobic dive limit (cADL = 17.9 ± 4.4  min SD) from blood and muscle oxygen stores and published metabolic rates of Weddell seals within (9-16 years, n = 24) and beyond peak-reproductive age (17-27 years, n = 26), to investigate (1) senescent constraints in apneustic hunting, and (2) whether mass or age primarily determines oxygen stores and ADL in older seals. We compared cADL with behavioral ADL from 5,275 free-ranging dives (bADL = 24.0 ± 5.3 min, n = 18 females). We observed no changes in Weddell seal oxygen stores, its determinants, or in ADLs late in life. Oxygen stores were better predicted by mass than age, consistent with published findings for young adults. Hematological panels (n = 6) were consistent across mass and age, though hematocrit (females > males, 6% elevation) and mean corpuscular hemoglobin content (females < males, 8% reduction) varied by sex. Whole blood viscosity was decreased with increasing mass in females and was higher than in males overall (+18%). This was largely due to elevated hematocrit in females, although plasma viscosity also varied under some conditions. Females had higher blood volume and elevated blood oxygen stores (vol% body mass), which did not translate into significantly higher cADL (18.1 vs. 17.1 min for males). Neither cADL nor bADL were mass- or age-dependent. PMID:21898850

  3. Cardiorespiratory and neural consequences of rats brought past their aerobic dive limit.

    PubMed

    Panneton, W Michael; Gan, Qi; Dahms, Thomas E

    2010-10-01

    The mammalian diving response is a dramatic autonomic adjustment to underwater submersion affecting heart rate, arterial blood pressure, and ventilation. The bradycardia is known to be modulated by the parasympathetic nervous system, arterial blood pressure is modulated via the sympathetic system, and still other circuits modulate the respiratory changes. In the present study, we investigate the submergence of rats brought past their aerobic dive limit, defined as the diving duration beyond which blood lactate concentration increases above resting levels. Hemodynamic measurements were made during underwater submergence with biotelemetric transmitters, and blood was drawn from cannulas previously implanted in the rats' carotid arteries. Such prolonged submersion induces radical changes in blood chemistry; mean arterial PCO(2) rose to 62.4 Torr, while mean arterial PO(2) and pH reached nadirs of 21.8 Torr and 7.18, respectively. Despite these radical changes in blood chemistry, the rats neither attempted to gasp nor breathe while underwater. Immunohistochemistry for Fos protein done on their brains revealed numerous Fos-positive profiles. Especially noteworthy were the large number of immunopositive profiles in loci where presumptive chemoreceptors are found. Despite the activation of these presumptive chemoreceptors, the rats did not attempt to breathe. Injections of biotinylated dextran amine were made into ventral parts of the medullary dorsal horn, where central fibers of the anterior ethmoidal nerve terminate. Labeled fibers coursed caudal, ventral, and medial from the injection to neurons on the ventral surface of the medulla, where numerous Fos-labeled profiles were seen in the rats brought past their aerobic dive limit. We propose that this projection inhibits the homeostatic chemoreceptor reflex, despite the gross activation of chemoreceptors. PMID:20705947

  4. Development of the aerobic dive limit and muscular efficiency in northern fur seals (Callorhinus ursinus).

    PubMed

    Shero, Michelle R; Andrews, Russel D; Lestyk, Keri C; Burns, Jennifer M

    2012-04-01

    Northern fur seal (Callorhinus ursinus; NFS) populations have been declining, perhaps due to limited foraging ability of pups. Because a marine mammal's proficiency at exploiting underwater prey resources is based on the ability to store large amounts of oxygen (O(2)) and to utilize these reserves efficiently, this study was designed to determine if NFS pups had lower blood, muscle, and total body O(2) stores than adults. Pups (<1-month old) had a calculated aerobic dive limit only ~40% of adult females due to lower blood and, to a much greater extent, muscle O(2) stores. Development of the Pectoralis (Pec) and Longissimus dorsi (LD) skeletal muscles was further examined by determining their myosin heavy chain (MHC) composition and enzyme activities. In all animals, the slow MHC I and fast-twitch IIA proteins typical of oxidative fiber types were dominant, but adult muscles contained more (Pec ~50%; LD ~250% higher) fast-twitch MHC IID/X protein characteristic of glycolytic muscle fibers, than pup muscles. This suggests that adults have greater ability to generate muscle power rapidly and/or under anaerobic conditions. Pup muscles also had lower aerobic and anaerobic ATP production potential, as indicated by lower metabolically scaled citrate synthase, β-hydroxyacyl CoA dehydrogenase, and lactate dehydrogenase activities (all P values ≤0.001). In combination, these findings indicate that pups are biochemically and physiologically limited in their diving capabilities relative to adults. This may contribute to lower NFS first year survival. PMID:22001970

  5. The marine mammal dive response is exercise modulated to maximize aerobic dive duration.

    PubMed

    Davis, Randall W; Williams, Terrie M

    2012-08-01

    When aquatically adapted mammals and birds swim submerged, they exhibit a dive response in which breathing ceases, heart rate slows, and blood flow to peripheral tissues and organs is reduced. The most intense dive response occurs during forced submersion which conserves blood oxygen for the brain and heart, thereby preventing asphyxiation. In free-diving animals, the dive response is less profound, and energy metabolism remains aerobic. However, even this relatively moderate bradycardia seems diametrically opposed to the normal cardiovascular response (i.e., tachycardia and peripheral vasodilation) during physical exertion. As a result, there has been a long-standing paradox regarding how aquatic mammals and birds exercise while submerged. We hypothesized based on cardiovascular modeling that heart rate must increase to ensure adequate oxygen delivery to active muscles. Here, we show that heart rate (HR) does indeed increase with flipper or fluke stroke frequency (SF) during voluntary, aerobic dives in Weddell seals (HR = 1.48SF - 8.87) and bottlenose dolphins (HR = 0.99SF + 2.46), respectively, two marine mammal species with different evolutionary lineages. These results support our hypothesis that marine mammals maintain aerobic muscle metabolism while swimming submerged by combining elements of both dive and exercise responses, with one or the other predominating depending on the level of exertion. PMID:22585422

  6. A review of the multi-level adaptations for maximizing aerobic dive duration in marine mammals: from biochemistry to behavior.

    PubMed

    Davis, Randall W

    2014-01-01

    Marine mammals exhibit multi-level adaptations, from cellular biochemistry to behavior, that maximize aerobic dive duration. A dive response during aerobic dives enables the efficient use of blood and muscle oxygen stores, but it is exercise modulated to maximize the aerobic dive limit at different levels of exertion. Blood volume and concentrations of blood hemoglobin and muscle myoglobin are elevated and serve as a significant oxygen store that increases aerobic dive duration. However, myoglobin is not homogeneously distributed in the locomotory muscles and is highest in areas that produce greater force and consume more oxygen during aerobic swimming. Muscle fibers are primarily fast and slow twitch oxidative with elevated mitochondrial volume densities and enhanced oxidative enzyme activities that are highest in areas that produce more force generation. Most of the muscle mitochondria are interfibriller and homogeneously distributed. This reduces the diffusion distance between mitochondria and helps maintain aerobic metabolism under hypoxic conditions. Mitochondrial volume densities and oxidative enzyme activities are also elevated in certain organs such as liver, kidneys, and stomach. Hepatic and renal function along with digestion and assimilation continue during aerobic dives to maintain physiological homeostasis. Most ATP production comes from aerobic fat metabolism in carnivorous marine mammals. Glucose is derived mostly from gluconeogenesis and is conserved for tissues such as red blood cells and the central nervous system. Marine mammals minimize the energetic cost of swimming and diving through body streamlining, efficient, lift-based propulsive appendages, and cost-efficient modes of locomotion that reduce drag and take advantage of changes in buoyancy with depth. Most dives are within the animal's aerobic dive limit, which maximizes time underwater and minimizes recovery time at the surface. The result of these adaptations is increased breath

  7. Heart rate and aerobic metabolism in Humboldt penguins, Spheniscus humboldti, during voluntary dives.

    PubMed

    Butler, P J; Woakes, A J

    1984-01-01

    Heart rate and aerobic metabolism have been recorded from three Humboldt penguins, Spheniscus humboldti, freely diving on a freshwater pond (9 X 4.6 X 2.7 m deep), using an implanted radiotransmitter and an open circuit respirometer. Oxygen uptake at mean dive duration (46.2s) was 26% greater than the resting value, but the difference was not statistically significant. Heart rate was also similar to the resting value. It is concluded that voluntary dives of penguins are completely aerobic and that oxygen stores are sufficient to allow metabolism to continue at the rate estimated in the present study for 2.27 min during voluntary submersion. This is longer than that calculated for tufted ducks, probably because the penguins are more efficient at underwater locomotion and because they are almost neutrally buoyant. PMID:6423763

  8. Aerobic exercise before diving reduces venous gas bubble formation in humans

    PubMed Central

    Dujić, Željko; Duplančic, Darko; Marinovic-Terzić, Ivana; Baković, Darija; Ivančev, Vladimir; Valic, Zoran; Eterović, Davor; Petri, Nadan M; Wisløff, Ulrik; Brubakk, Alf O

    2004-01-01

    We have previously shown in a rat model that a single bout of high-intensity aerobic exercise 20h before a simulated dive reduces bubble formation and after the dive protects from lethal decompression sickness. The present study investigated the importance of these findings in man. Twelve healthy male divers were compressed in a hyperbaric chamber to 280kPa at a rate of 100kPamin−1 breathing air and remaining at pressure for 80min. The ascent rate was 9mmin−1 with a 7min stop at 130kPa. Each diver underwent two randomly assigned simulated dives, with or without preceding exercise. A single interval exercise performed 24h before the dive consisted of treadmill running at 90% of maximum heart rate for 3min, followed by exercise at 50% of maximum heart rate for 2min; this was repeated eight times for a total exercise period of 40min. Venous gas bubbles were monitored with an ultrasonic scanner every 20min for 80min after reaching surface pressure. The study demonstrated that a single bout of strenuous exercise 24h before a dive to 18 m of seawater significantly reduced the average number of bubbles in the pulmonary artery from 0.98 to 0.22 bubbles cm−2(P= 0.006) compared to dives without preceding exercise. The maximum bubble grade was decreased from 3 to 1.5 (P= 0.002) by pre-dive exercise, thereby increasing safety. This is the first report to indicate that pre-dive exercise may form the basis for a new way of preventing serious decompression sickness. PMID:14755001

  9. Aerobic exercise before diving reduces venous gas bubble formation in humans.

    PubMed

    Dujic, Zeljko; Duplancic, Darko; Marinovic-Terzic, Ivana; Bakovic, Darija; Ivancev, Vladimir; Valic, Zoran; Eterovic, Davor; Petri, Nadan M; Wisløff, Ulrik; Brubakk, Alf O

    2004-03-16

    We have previously shown in a rat model that a single bout of high-intensity aerobic exercise 20 h before a simulated dive reduces bubble formation and after the dive protects from lethal decompression sickness. The present study investigated the importance of these findings in man. Twelve healthy male divers were compressed in a hyperbaric chamber to 280 kPa at a rate of 100 kPa min(-1) breathing air and remaining at pressure for 80 min. The ascent rate was 9 m min(-1) with a 7 min stop at 130 kPa. Each diver underwent two randomly assigned simulated dives, with or without preceding exercise. A single interval exercise performed 24h before the dive consisted of treadmill running at 90% of maximum heart rate for 3 min, followed by exercise at 50% of maximum heart rate for 2 min; this was repeated eight times for a total exercise period of 40 min. Venous gas bubbles were monitored with an ultrasonic scanner every 20 min for 80 min after reaching surface pressure. The study demonstrated that a single bout of strenuous exercise 24h before a dive to 18 m of seawater significantly reduced the average number of bubbles in the pulmonary artery from 0.98 to 0.22 bubbles cm(-2)(P= 0.006) compared to dives without preceding exercise. The maximum bubble grade was decreased from 3 to 1.5 (P= 0.002) by pre-dive exercise, thereby increasing safety. This is the first report to indicate that pre-dive exercise may form the basis for a new way of preventing serious decompression sickness. PMID:14755001

  10. Heart rate regulation and extreme bradycardia in diving emperor penguins.

    PubMed

    Meir, Jessica U; Stockard, Torre K; Williams, Cassondra L; Ponganis, Katherine V; Ponganis, Paul J

    2008-04-01

    To investigate the diving heart rate (f(H)) response of the emperor penguin (Aptenodytes forsteri), the consummate avian diver, birds diving at an isolated dive hole in McMurdo Sound, Antarctica were outfitted with digital electrocardiogram recorders, two-axis accelerometers and time depth recorders (TDRs). In contrast to any other freely diving bird, a true bradycardia (f(H) significantly diving [dive f(H) (total beats/duration)=57+/-2 beats min(-1), f(H) at rest=73+/-2 beats min(-1) (mean +/- s.e.m.)]. For dives less than the aerobic dive limit (ADL; duration beyond which [blood lactate] increases above resting levels), dive f(H)=85+/-3 beats min(-1), whereas f(H) in dives greater than the ADL was significantly lower (41+/-1 beats min(-1)). In dives greater than the ADL, f(H) reached extremely low values: f(H) during the last 5 mins of an 18 min dive was 6 beats min(-1). Dive f(H) and minimum instantaneous f(H) during dives declined significantly with increasing dive duration. Dive f(H) was independent of swim stroke frequency. This suggests that progressive bradycardia and peripheral vasoconstriction (including isolation of muscle) are primary determinants of blood oxygen depletion in diving emperor penguins. Maximum instantaneous surface interval f(H) in this study is the highest ever recorded for emperor penguins (256 beats min(-1)), equivalent to f(H) at V(O(2)) max., presumably facilitating oxygen loading and post-dive metabolism. The classic Scholander-Irving dive response in these emperor penguins contrasts with the absence of true bradycardia in diving ducks, cormorants, and other penguin species. PMID:18375841

  11. Cellular hallmarks reveal restricted aerobic metabolism at thermal limits

    PubMed Central

    Neves, Aitana; Busso, Coralie; Gönczy, Pierre

    2015-01-01

    All organisms live within a given thermal range, but little is known about the mechanisms setting the limits of this range. We uncovered cellular features exhibiting signature changes at thermal limits in Caenorhabditis elegans embryos. These included changes in embryo size and shape, which were also observed in Caenorhabditis briggsae, indicating evolutionary conservation. We hypothesized that such changes could reflect restricted aerobic capacity at thermal limits. Accordingly, we uncovered that relative respiration in C. elegans embryos decreases at the thermal limits as compared to within the thermal range. Furthermore, by compromising components of the respiratory chain, we demonstrated that the reliance on aerobic metabolism is reduced at thermal limits. Moreover, embryos thus compromised exhibited signature changes in size and shape already within the thermal range. We conclude that restricted aerobic metabolism at the thermal limits contributes to setting the thermal range in a metazoan organism. DOI: http://dx.doi.org/10.7554/eLife.04810.001 PMID:25929283

  12. Breathing hypoxic gas affects the physiology as well as the diving behaviour of tufted ducks.

    PubMed

    Halsey, Lewis G; Butler, Patrick J; Woakes, Anthony J

    2005-01-01

    We measured the effects of exposure to hypoxia (15% and 11% oxygen) and hypercapnia (up to 4.5% carbon dioxide) on rates of respiratory gas exchange both between and during dives in tufted ducks, Aythya fuligula, to investigate to what extent these may explain changes in diving behaviour. As found in previous studies, the ducks decreased dive duration (t(d)) and increased surface duration when diving from a hypoxic or hypercapnic gas mix. In the hypercapnic conditions, oxygen consumption during the dive cycle was not affected. Oxygen uptake between dives was reduced by only 17% when breathing a hypoxic gas mix of 11% oxygen. However, estimates of the rate of oxygen metabolism during the foraging periods of dives decreased nearly threefold in 11% oxygen. Given that tufted ducks normally dive well within their aerobic dive limits and that they significantly reduced their t(d) during hypoxia, it is not at all clear why they make this physiological adjustment. PMID:15778946

  13. Summer diving behavior of male walruses in Bristol Bay, Alaska

    USGS Publications Warehouse

    Jay, C.V.; Farley, Sean D.; Garner, G.W.

    2001-01-01

    Pacific walruses (Odobenus rosmarus divergens) make trips from ice or land haul-out sites to forage for benthic prey. We describe dive and trip characteristics from time-depth-recorder data collected over a one-month period during summer from four male Pacific walruses in Bristol Bay, Alaska. Dives were classified into four types. Shallow (4 m), short (2.7 min), square-shaped dives accounted for 11% of trip time, and many were probably associated with traveling. Shallow (2 m) and very short (0.5 min) dives composed only 1% of trip time. Deep (41 m), long (7.2 min), square-shaped dives accounted for 46% of trip time and were undoubtedly associated with benthic foraging. V-shaped dives ranged widely in depth, were of moderate duration (4.7 min), and composed 3% of trip time. These dives may have been associated with navigation or exploration of the seafloor for potential prey habitat. Surface intervals between dives were similar among dive types, and generally lasted 1-2 min. Total foraging time was strongly correlated with trip duration and there was no apparent diel pattern of diving in any dive type among animals. We found no correlation between dive duration and postdive surface interval within dive types, suggesting that diving occurred within aerobic dive limits. Trip duration varied considerably within and among walruses (0.3-9.4 d), and there was evidence that some of the very short trips were unrelated to foraging. Overall, walruses were in the water for 76.6% of the time, of which 60.3% was spent diving.

  14. Repeated parallel evolution reveals limiting similarity in subterranean diving beetles.

    PubMed

    Vergnon, Remi; Leijs, Remko; van Nes, Egbert H; Scheffer, Marten

    2013-07-01

    The theory of limiting similarity predicts that co-occurring species must be sufficiently different to coexist. Although this idea is a staple of community ecology, convincing empirical evidence has been scarce. Here we examine 34 subterranean beetle communities in arid inland Australia that share the same habitat type but have evolved in complete isolation over the past 5 million years. Although these communities come from a range of phylogenetic origins, we find that they have almost invariably evolved to share a similar size structure. The relative positions of coexisting species on the body size axis were significantly more regular across communities than would be expected by chance, with a size ratio, on average, of 1.6 between coexisting species. By contrast, species' absolute body sizes varied substantially from one community to the next. This suggests that self-organized spacing according to limiting-similarity theory, as opposed to evolution toward preexisting fixed niches, shaped the communities. Using a model starting from random sets of founder species, we demonstrate that the patterns are indeed consistent with evolutionary self-organization. For less isolated habitats, the same model predicts the coexistence of multiple species in each regularly spaced functional group. Limiting similarity, therefore, may also be compatible with the coexistence of many redundant species. PMID:23778227

  15. Courtship dives of Anna's hummingbird offer insights into flight performance limits

    PubMed Central

    Clark, Christopher James

    2009-01-01

    Behavioural displays are a common feature of animal courtship. Just as female preferences can generate exaggerated male ornaments, female preferences for dynamic behaviours may cause males to perform courtship displays near intrinsic performance limits. I provide an example of an extreme display, the courtship dive of Anna's hummingbird (Calypte anna). Diving male Anna's hummingbirds were filmed with a combination of high-speed and conventional video cameras. After powering the initial stage of the dive by flapping, males folded their wings by their sides, at which point they reached an average maximum velocity of 385 body lengths s−1 (27.3 m s−1). This is the highest known length-specific velocity attained by any vertebrate. This velocity suggests their body drag coefficient is less than 0.3. They then spread their wings to pull up, and experienced centripetal accelerations nearly nine times greater than gravitational acceleration. This acceleration is the highest reported for any vertebrate undergoing a voluntary aerial manoeuvre, except jet fighter pilots. Stereotyped courtship behaviours offer several advantages for the study of extreme locomotor performance, and can be assessed in a natural context. PMID:19515669

  16. Point of no return in diving emperor penguins: is the timing of the decision to return limited by the number of strokes?

    PubMed

    Shiomi, Kozue; Sato, Katsufumi; Ponganis, Paul J

    2012-01-01

    At some point in a dive, breath-hold divers must decide to return to the surface to breathe. The issue of when to end a dive has been discussed intensively in terms of foraging ecology and behavioral physiology, using dive duration as a temporal parameter. Inevitably, however, a time lag exists between the decision of animals to start returning to the surface and the end of the dive, especially in deep dives. In the present study, we examined the decision time in emperor penguins under two different conditions: during foraging trips at sea and during dives at an artificial isolated dive hole. It was found that there was an upper limit for the decision-to-return time irrespective of dive depth in birds diving at sea. However, in a large proportion of dives at the isolated dive hole, the decision-to-return time exceeded the upper limit at sea. This difference between the decision times in dives at sea versus the isolated dive hole was accounted for by a difference in stroke rate. The stroke rates were much lower in dives at the isolated hole and were inversely correlated with the upper limit of decision times in individual birds. Unlike the decision time to start returning, the cumulative number of strokes at the decision time fell within a similar range in the two experiments. This finding suggests that the number of strokes, but not elapsed time, constrained the decision of emperor penguins to return to the surface. While the decision to return and to end a dive may be determined by a variety of ecological, behavioral and physiological factors, the upper limit to that decision time may be related to cumulative muscle workload. PMID:22162861

  17. Travelers' Health: Scuba Diving

    MedlinePlus

    ... no-decompression limits of their dive tables or computers. Risk factors for DCI are primarily dive depth, ... 12]. Available from: http://www.diversalertnetwork.org/research/projects/fad/workshop/FADWorkshopProceedings.pdf . Chapter 2 - Environmental Hazards ...

  18. O2 store management in diving emperor penguins

    PubMed Central

    Ponganis, P. J.; Stockard, T. K.; Meir, J. U.; Williams, C. L.; Ponganis, K. V.; Howard, R.

    2009-01-01

    Summary In order to further define O2 store utilization during dives and understand the physiological basis of the aerobic dive limit (ADL, dive duration associated with the onset of post-dive blood lactate accumulation), emperor penguins (Aptenodytes forsteri) were equipped with either a blood partial pressure of oxygen (PO2) recorder or a blood sampler while they were diving at an isolated dive hole in the sea ice of McMurdo Sound, Antarctica. Arterial PO2 profiles (57 dives) revealed that (a) pre-dive PO2 was greater than that at rest, (b) PO2 transiently increased during descent and (c) post-dive PO2 reached that at rest in 1.92±1.89 min (N=53). Venous PO2 profiles (130 dives) revealed that (a) pre-dive venous PO2 was greater than that at rest prior to 61% of dives, (b) in 90% of dives venous PO2 transiently increased with a mean maximum PO2 of 53±18 mmHg and a mean increase in PO2 of 11±12 mmHg, (c) in 78% of dives, this peak venous PO2 occurred within the first 3 min, and (d) post-dive venous PO2 reached that at rest within 2.23±2.64 min (N=84). Arterial and venous PO2 values in blood samples collected 1–3 min into dives were greater than or near to the respective values at rest. Blood lactate concentration was less than 2 mmol l–1 as far as 10.5 min into dives, well beyond the known ADL of 5.6 min. Mean arterial and venous PN2 of samples collected at 20–37 m depth were 2.5 times those at the surface, both being 2.1±0.7 atmospheres absolute (ATA; N=3 each), and were not significantly different. These findings are consistent with the maintenance of gas exchange during dives (elevated arterial and venous PO2 and PN2 during dives), muscle ischemia during dives (elevated venous PO2, lack of lactate washout into blood during dives), and arterio-venous shunting of blood both during the surface period (venous PO2 greater than that at rest) and during dives (arterialized venous PO2 values during descent, equivalent arterial and venous PN2 values during

  19. Rapid brain cooling in diving ducks.

    PubMed

    Caputa, M; Folkow, L; Blix, A S

    1998-08-01

    Hypothermia may limit asphyxic damages to the brain, and many small homeotherms have been shown to use anapyrexic strategies when exposed to asphyxic conditions. Larger homeotherms do not seem to use the same strategy, but could save oxygen and prevent hypoxic brain damage by employing selective brain cooling (SBC) in connection with asphyxia. To test the hypothesis that selective brain cooling may take place in connection with asphyxia, we have recorded brain [hypothalamic (THyp)] and body [colonic (TC)] temperatures and heart rates in four Pekin ducks during 5-min simulated (head submersion) diving in cold water (10 degrees C). Diving resulted in a drop in THyp (3.1 +/- 1.4 degrees C) that continued into the recovery period (P < 0.001). Restricting heat loss from the buccal cavity and eyes during diving compromised brain cooling in an additive manner. TC was not influenced by diving. Control cooling of the head with crushed ice during a 5-min period of undisturbed breathing had no effect on THyp. Warm water (35 degrees C) markedly reduced brain cooling, and dive capacity was reduced by approximately 14% (P < 0.05) compared with diving in water at 10 degrees C. The data suggest that SBC is used in ducks during diving, and we propose that this mechanism may enable the bird to save oxygen for prolonged aerobic submergence and to protect the brain from asphyxic damages. PMID:9688670

  20. Cardiac responses of grey seals during diving at sea.

    PubMed

    Thompson, D; Fedak, M A

    1993-01-01

    Heart rate, swimming speed and diving depth data were collected from free-ranging grey seals, Halichoerus grypus, as they foraged and travelled in the sea around the Hebrides Islands off western Scotland. Information was collected on a tracking yacht using a combination of sonic and radio telemetry. Diving heart rate declined as a function of dive duration. In long dives, grey seals employed extreme bradycardia, with heart rates falling to 4 beats min-1 for extended periods, despite the animal being free to breath at will. This extreme dive response is part of the normal foraging behaviour. Seals spent 89% of the time submerged during bouts of long dives; swimming was restricted to ascent and descent. Dive durations exceeded estimated aerobic dive limit, even assuming resting metabolic rates. These results indicate that behavioural, and possibly cellular, energy-sparing mechanisms play an important role in diving behaviour of grey seals. This has implications not only for studies of mammalian energetics but also for our understanding of the foraging tactics and prey selection of marine mammals. If some seals are using energy-sparing mechanisms to reduce metabolic costs while at depth, they may be forced to wait for and ambush prey rather than to search for and chase it. PMID:8440964

  1. Novel locomotor muscle design in extreme deep-diving whales.

    PubMed

    Velten, B P; Dillaman, R M; Kinsey, S T; McLellan, W A; Pabst, D A

    2013-05-15

    Most marine mammals are hypothesized to routinely dive within their aerobic dive limit (ADL). Mammals that regularly perform deep, long-duration dives have locomotor muscles with elevated myoglobin concentrations that are composed of predominantly large, slow-twitch (Type I) fibers with low mitochondrial volume densities (V(mt)). These features contribute to extending ADL by increasing oxygen stores and decreasing metabolic rate. Recent tagging studies, however, have challenged the view that two groups of extreme deep-diving cetaceans dive within their ADLs. Beaked whales (including Ziphius cavirostris and Mesoplodon densirostris) routinely perform the deepest and longest average dives of any air-breathing vertebrate, and short-finned pilot whales (Globicephala macrorhynchus) perform high-speed sprints at depth. We investigated the locomotor muscle morphology and estimated total body oxygen stores of several species within these two groups of cetaceans to determine whether they (1) shared muscle design features with other deep divers and (2) performed dives within their calculated ADLs. Muscle of both cetaceans displayed high myoglobin concentrations and large fibers, as predicted, but novel fiber profiles for diving mammals. Beaked whales possessed a sprinter's fiber-type profile, composed of ~80% fast-twitch (Type II) fibers with low V(mt). Approximately one-third of the muscle fibers of short-finned pilot whales were slow-twitch, oxidative, glycolytic fibers, a rare fiber type for any mammal. The muscle morphology of beaked whales likely decreases the energetic cost of diving, while that of short-finned pilot whales supports high activity events. Calculated ADLs indicate that, at low metabolic rates, both beaked and short-finned pilot whales carry sufficient onboard oxygen to aerobically support their dives. PMID:23393275

  2. Energetic costs of surface swimming and diving of birds.

    PubMed

    Butler, P J

    2000-01-01

    The energetic costs of swimming at the surface (swimming) and swimming underwater (diving) are compared in tufted ducks (Aythya fuligula) and three species of penguins, the gentoo (Pygoscelis papua), the king (Aptenodytes patagonicus), and the emperor (Aythya forsteri). Ducks swim on the surface and use their webbed feet as paddles, whereas penguins tend to swim just below the surface and use their flippers as hydrofoils, the latter being much more efficient. Penguins are more streamlined in shape. Thus, the amount of energy required to transport a given mass of bird a given distance (known as the cost of transport) is some two to three times greater in ducks than in penguins. Ducks are also very buoyant, and overcoming the force of buoyancy accounts for 60% and 85% of the cost of descent and remaining on the bottom, respectively, in these birds. The energy cost of a tufted duck diving to about 1.7 m is similar to that when it is swimming at its maximum sustainable speed at the surface (i.e., approximately 3.5 times the value when resting on water). Nonetheless, because of the relatively short duration of its dives, the tufted duck dives well within its calculated aerobic dive limit (cADL, usable O(2) stores per rate of O(2) usage when underwater). However, these three species of penguins have maximum dive durations ranging from 5 min to almost 16 min and maximum dive depths from 155 to 530 m. When these birds dive, they have to metabolise at no more than when resting in water in order for cADL to encompass the duration of most of their natural dives. In gentoo and king penguins, there is a fall in abdominal temperature during bouts of diving; this may reduce the oxygen requirements in the abdominal region, thus enabling dive duration to be extended further than would otherwise be the case. PMID:11121344

  3. Niche overlap, threshold food densities, and limits to prey depletion for a diving duck assemblage in an estuarine bay

    USGS Publications Warehouse

    Lovvorn, James R.; De La Cruz, Susan; Takekawa, John Y.; Shaskey, Laura E.; Richman, Samantha E.

    2013-01-01

    Planning for marine conservation often requires estimates of the amount of habitat needed to support assemblages of interacting species. During winter in subtidal San Pablo Bay, California, the 3 main diving duck species are lesser scaup Aythya affinis (LESC), greater scaup A. marila (GRSC), and surf scoter Melanitta perspicillata (SUSC), which all feed almost entirely on the bivalve Corbula amurensis. Decreased body mass and fat, increased foraging effort, and major departures of these birds appeared to result from food limitation. Broad overlap in prey size, water depth, and location suggested that the 3 species responded similarly to availability of the same prey. However, an energetics model that accounts for differing body size, locomotor mode, and dive behavior indicated that each species will become limited at different stages of prey depletion in the order SUSC, then GRSC, then LESC. Depending on year, 35 to 66% of the energy in Corbula standing stocks was below estimated threshold densities for profitable foraging. Ectothermic predators, especially flounders and sturgeons, could reduce excess carrying capacity for different duck species by 4 to 10%. A substantial quantity of prey above profitability thresholds was not exploited before most ducks left San Pablo Bay. Such pre-depletion departure has been attributed in other taxa to foraging aggression. However, in these diving ducks that showed no overt aggression, this pattern may result from high costs of locating all adequate prey patches, resulting reliance on existing flocks to find food, and propensity to stay near dense flocks to avoid avian predation. For interacting species assemblages, modeling profitability thresholds can indicate the species most vulnerable to food declines. However, estimates of total habitat needed require better understanding of factors affecting the amount of prey above thresholds that is not depleted before the predators move elsewhere.

  4. 29 CFR 1910.424 - SCUBA diving.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 5 2012-07-01 2012-07-01 false SCUBA diving. 1910.424 Section 1910.424 Labor Regulations... SCUBA diving. (a) General. Employers engaged in SCUBA diving shall comply with the following requirements, unless otherwise specified. (b) Limits. SCUBA diving shall not be conducted: (1) At depths...

  5. 29 CFR 1910.424 - SCUBA diving.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 5 2014-07-01 2014-07-01 false SCUBA diving. 1910.424 Section 1910.424 Labor Regulations... SCUBA diving. (a) General. Employers engaged in SCUBA diving shall comply with the following requirements, unless otherwise specified. (b) Limits. SCUBA diving shall not be conducted: (1) At depths...

  6. 29 CFR 1910.424 - SCUBA diving.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 5 2013-07-01 2013-07-01 false SCUBA diving. 1910.424 Section 1910.424 Labor Regulations... SCUBA diving. (a) General. Employers engaged in SCUBA diving shall comply with the following requirements, unless otherwise specified. (b) Limits. SCUBA diving shall not be conducted: (1) At depths...

  7. Condition and mass impact oxygen stores and dive duration in adult female northern elephant seals.

    PubMed

    Hassrick, J L; Crocker, D E; Teutschel, N M; McDonald, B I; Robinson, P W; Simmons, S E; Costa, D P

    2010-02-15

    The range of foraging behaviors available to deep-diving, air-breathing marine vertebrates is constrained by their physiological capacity to breath-hold dive. We measured body oxygen stores (blood volume and muscle myoglobin) and diving behavior in adult female northern elephant seals, Mirounga angustirostris, to investigate age-related effects on diving performance. Blood volume averaged 74.4+/-17.0 liters in female elephant seals or 20.2+/-2.0% of body mass. Plasma volume averaged 32.2+/-7.8 liters or 8.7+/-0.7% of body mass. Absolute plasma volume and blood volume increased independently with mass and age. Hematocrit decreased weakly with mass but did not vary with age. Muscle myoglobin concentration, while higher than previously reported (7.4+/-0.7 g%), did not vary with mass or age. Pregnancy status did not influence blood volume. Mean dive duration, a proxy for physiological demand, increased as a function of how long seals had been at sea, followed by mass and hematocrit. Strong effects of female body mass (range, 218-600 kg) on dive duration, which were independent of oxygen stores, suggest that larger females had lower diving metabolic rates. A tendency for dives to exceed calculated aerobic limits occurred more frequently later in the at-sea migration. Our data suggest that individual physiological state variables and condition interact to determine breath-hold ability and that both should be considered in life-history studies of foraging behavior. PMID:20118309

  8. The effects of experimentally induced hyperthyroidism on the diving physiology of harbor seals (Phoca vitulina)

    PubMed Central

    Weingartner, Gundula M.; Thornton, Sheila J.; Andrews, Russel D.; Enstipp, Manfred R.; Barts, Agnieszka D.; Hochachka, Peter W.

    2012-01-01

    Many phocid seals are expert divers that remain submerged longer than expected based on estimates of oxygen storage and utilization. This discrepancy is most likely due to an overestimation of diving metabolic rate. During diving, a selective redistribution of blood flow occurs, which may result in reduced metabolism in the hypoperfused tissues and a possible decline in whole-body metabolism to below the resting level (hypometabolism). Thyroid hormones are crucial in regulation of energy metabolism in vertebrates and therefore their control might be an important part of achieving a hypometabolic state during diving. To investigate the effect of thyroid hormones on diving physiology of phocid seals, we measured oxygen consumption, heart rate, and post-dive lactate concentrations in five harbor seals (Phoca vitulina) conducting 5 min dives on command, in both euthyroid and experimentally induced hyperthyroid states. Oxygen consumption during diving was significantly reduced (by 25%) in both euthyroid and hyperthyroid states, confirming that metabolic rate during diving falls below resting levels. Hyperthyroidism increased oxygen consumption (by 7–8%) when resting in water and during diving, compared with the euthyroid state, illustrating the marked effect of thyroid hormones on metabolic rate. Consequently, post-dive lactate concentrations were significantly increased in the hyperthyroid state, suggesting that the greater oxygen consumption rates forced seals to make increased use of anaerobic metabolic pathways. During diving, hyperthyroid seals also exhibited a more profound decline in heart rate than seals in the euthyroid state, indicating that these seals were pushed toward their aerobic limit and required a more pronounced cardiovascular response. Our results demonstrate the powerful role of thyroid hormones in metabolic regulation and support the hypothesis that thyroid hormones play a role in modulating the at-sea metabolism of phocid seals. PMID:23060807

  9. Diving emergencies.

    PubMed

    DeGorordo, Antonio; Vallejo-Manzur, Federico; Chanin, Katia; Varon, Joseph

    2003-11-01

    Self-Contained Underwater Breathing Apparatus (SCUBA) diving popularity is increasing tremendously, reaching a total of 9 million people in the US during 2001, and 50,000 in the UK in 1985. Over the past 10 years, new advances, equipment improvements, and improved diver education have made SCUBA diving safer and more enjoyable. Most diving injuries are related to the behaviour of the gases and pressure changes during descent and ascent. The four main pathologies in diving medicine include: barotrauma (sinus, otic, and pulmonary); decompression illness (DCI); pulmonary edema and pharmacological; and toxic effects of increased partial pressures of gases. The clinical manifestations of a diving injury may be seen during a dive or up to 24 h after it. Physicians living far away from diving places are not excluded from the possibility of encountering diver-injured patients and therefore need to be aware of these injuries. This article reviews some of the principles of diving and pathophysiology of diving injuries as well as the acute treatment, and further management of these patients. PMID:14625107

  10. Fatty Acid use in Diving Mammals: More than Merely Fuel

    PubMed Central

    Trumble, Stephen J.; Kanatous, Shane B.

    2012-01-01

    Diving mammals, are under extreme pressure to conserve oxygen as well as produce adequate energy through aerobic pathways during breath-hold diving. Typically a major source of energy, lipids participate in structural and regulatory roles and have an important influence on the physiological functions of an organism. At the stoichiometric level, the metabolism of polyunsaturated fatty acids (PUFAs) utilizes less oxygen than metabolizing either monounsaturated fatty acids or saturated fatty acids (SFAs) and yields fewer ATP per same length fatty acid. However, there is evidence that indicates the cellular metabolic rate is directly correlated to the lipid composition of the membranes such that the greater the PUFA concentration in the membranes the greater the metabolic rate. These findings appear to be incompatible with diving mammals that ingest and metabolize high levels of unsaturated fatty acids while relying on stored oxygen. Growing evidence from birds to mammals including recent evidence in Weddell seals also indicates that at the whole animal level the utilization of PUFAs to fuel their metabolism actually conserves oxygen. In this paper, we make an initial attempt to ascertain the beneficial adaptations or limitations of lipids constituents and potential trade-offs in diving mammals. We discuss how changes in Antarctic climate are predicted to have numerous different environmental effects; such potential shifts in the availability of certain prey species or even changes in the lipid composition (increased SFA) of numerous fish species with increasing water temperatures and how this may impact the diving ability of Weddell seals. PMID:22707938

  11. Diving Related Changes in the Blood Oxygen Stores of Rehabilitating Harbor Seal Pups (Phoca vitulina).

    PubMed

    Thomas, Amber; Ono, Kathryn

    2015-01-01

    Harbor seal (Phoca vitulina) pups begin diving within hours of birth, stimulating the development of the blood oxygen (O2) stores necessary to sustain underwater aerobic metabolism. Since harbor seals experience a brief nursing period, the early-life development of these blood O2 stores is necessary for successful post-weaning foraging. If mothers and pups become prematurely separated, the pup may be transported to a wildlife rehabilitation center for care. Previous studies suggest that the shallow pools and lack of diving in rehabilitation facilities may lead to under-developed blood O2 stores, but diving behavior during rehabilitation has not been investigated. This study aimed to simultaneously study the diving behaviors and blood O2 store development of rehabilitating harbor seal pups. Standard hematology measurements (Hct, Hb, RBC, MCV, MCH, MCHC) were taken to investigate O2 storage capacity and pups were equipped with time-depth recorders to investigate natural diving behavior while in rehabilitation. Linear mixed models of the data indicate that all measured blood parameters changed with age; however, when compared to literature values for wild harbor seal pups, rehabilitating pups have smaller red blood cells (RBCs) that can store less hemoglobin (Hb) and subsequently, less O2, potentially limiting their diving capabilities. Wild pups completed longer dives at younger ages (maximum reported <25 days of age: 9 min) in previous studies than the captive pups in this study (maximum <25 days of age: 2.86 min). However, captivity may only affect the rate of development, as long duration dives were observed (maximum during rehabilitation: 13.6 min at 89 days of age). Further, this study suggests that there may be a positive relationship between RBC size and the frequency of long duration dives. Thus, rehabilitating harbor seal pups should be encouraged to make frequent, long duration dives to prepare themselves for post-release foraging. PMID:26061662

  12. Drift dives and prolonged surfacing periods in Baikal seals: resting strategies in open waters?

    PubMed

    Watanabe, Yuuki Y; Baranov, Eugene A; Miyazaki, Nobuyuki

    2015-09-01

    Many pinnipeds frequently rest on land or ice, but some species remain in open waters for weeks or months, raising the question of how they rest. A unique type of dive, called drift dives, has been reported for several pinnipeds with suggested functions of rest, food processing and predator avoidance. Prolonged surfacing periods have also been observed in captive seals and are thought to aid food processing. However, information from other species in a different environment would be required to better understand the nature and function of this behavior. In this study, we attached multi-sensor tags to Baikal seals Pusa sibirica, a rare, freshwater species that has no aquatic predators and few resting grounds during the ice-free season. The seals exhibited repeated drift dives (mean depth, 116 m; duration, 10.1 min) in the daytime and prolonged periods at the surface (mean duration, 1.3 h) mainly around dawn. Drift dives and prolonged surfacing periods were temporally associated and observed between a series of foraging dives, suggesting a similar function, i.e. a combination of resting and food processing. The maximum durations of both drift and foraging dives were 15.4 min, close to the aerobic dive limit of this species; therefore, metabolic rates might not be significantly depressed during drift dives, further supporting the function of food processing rather than purely resting. Our results also show that drift diving can occur in a predator-free environment, and thus predator avoidance is not a general explanation of drift dives in pinnipeds. PMID:26139663

  13. Diving Related Changes in the Blood Oxygen Stores of Rehabilitating Harbor Seal Pups (Phoca vitulina)

    PubMed Central

    Thomas, Amber; Ono, Kathryn

    2015-01-01

    Harbor seal (Phoca vitulina) pups begin diving within hours of birth, stimulating the development of the blood oxygen (O2) stores necessary to sustain underwater aerobic metabolism. Since harbor seals experience a brief nursing period, the early-life development of these blood O2 stores is necessary for successful post-weaning foraging. If mothers and pups become prematurely separated, the pup may be transported to a wildlife rehabilitation center for care. Previous studies suggest that the shallow pools and lack of diving in rehabilitation facilities may lead to under-developed blood O2 stores, but diving behavior during rehabilitation has not been investigated. This study aimed to simultaneously study the diving behaviors and blood O2 store development of rehabilitating harbor seal pups. Standard hematology measurements (Hct, Hb, RBC, MCV, MCH, MCHC) were taken to investigate O2 storage capacity and pups were equipped with time-depth recorders to investigate natural diving behavior while in rehabilitation. Linear mixed models of the data indicate that all measured blood parameters changed with age; however, when compared to literature values for wild harbor seal pups, rehabilitating pups have smaller red blood cells (RBCs) that can store less hemoglobin (Hb) and subsequently, less O2, potentially limiting their diving capabilities. Wild pups completed longer dives at younger ages (maximum reported <25 days of age: 9 min) in previous studies than the captive pups in this study (maximum <25 days of age: 2.86 min). However, captivity may only affect the rate of development, as long duration dives were observed (maximum during rehabilitation: 13.6 min at 89 days of age). Further, this study suggests that there may be a positive relationship between RBC size and the frequency of long duration dives. Thus, rehabilitating harbor seal pups should be encouraged to make frequent, long duration dives to prepare themselves for post-release foraging. PMID:26061662

  14. Diving medicine.

    PubMed

    Bove, Alfred A

    2014-06-15

    Exposure to the undersea environment has unique effects on normal physiology and can result in unique disorders that require an understanding of the effects of pressure and inert gas supersaturation on organ function and knowledge of the appropriate therapies, which can include recompression in a hyperbaric chamber. The effects of Boyle's law result in changes in volume of gas-containing spaces when exposed to the increased pressure underwater. These effects can cause middle ear and sinus injury and lung barotrauma due to lung overexpansion during ascent from depth. Disorders related to diving have unique presentations, and an understanding of the high-pressure environment is needed to properly diagnose and manage these disorders. Breathing compressed air underwater results in increased dissolved inert gas in tissues and organs. On ascent after a diving exposure, the dissolved gas can achieve a supersaturated state and can form gas bubbles in blood and tissues, with resulting tissue and organ damage. Decompression sickness can involve the musculoskeletal system, skin, inner ear, brain, and spinal cord, with characteristic signs and symptoms. Usual therapy is recompression in a hyperbaric chamber following well-established protocols. Many recreational diving candidates seek medical clearance for diving, and healthcare providers must be knowledgeable of the environmental exposure and its effects on physiologic function to properly assess individuals for fitness to dive. This review provides a basis for understanding the diving environment and its accompanying disorders and provides a basis for assessment of fitness for diving. PMID:24869752

  15. Diving birds

    NASA Astrophysics Data System (ADS)

    Clanet, Christophe; Masson, Lucien; McKinley, Gareth; Cohen, Robert; Ecole polytechnique Collaboration; MIT Collaboration

    2015-11-01

    Many seabirds (gannets, pelicans, gulls, albatrosses) dive into water at high speeds (25 m/s) in order to capture underwater preys. Diving depths of 20 body lengths are reported in the literature. This value is much larger than the one achieved by men, which is of the order of 5. We study this difference by comparing the impact of slender vs bluff bodies. We show that, contrary to bluff bodies, the penetration depth of slender bodies presents a maximum value for a specific impact velocity that we connect to the velocity of diving birds.

  16. Respiratory and cardiovascular control during diving in birds and mammals.

    PubMed

    Butler, P J

    1982-10-01

    Recent studies on freely diving birds and mammals indicate that, contrary to the classical hypothesis, the majority of dives are aerobic with minimal cardiovascular adjustments (i.e. bradycardia and selective vasoconstriction). It is postulated that during these aerobic dives the cardiovascular adjustments result from the opposing influences of exercise and the classical diving response, with the bias towards the exercise response. It is envisaged that the active muscles, as well as the brain and heart, are adequately supplied with blood to enable them to metabolize aerobically. Intense mental activity, particularly in carnivores seeking their prey, may also attenuate the classical response. Aerobic dives are usually terminated well before the oxygen stores are depleted, and another dive follows once they have been replenished. In this way a series of dives is performed. Prolonged dives are endured as a result of a shift towards the classical response of bradycardia, presumably more intense vasoconstriction, and anaerobiosis. This may be a form of alarm response, particularly in small animals such as ducks and coypus, or it may be a means of allowing the marine birds and mammals that dive deeply for their food to engage in unusually long hunting expeditions. For those that dive under ice, it may also allow long periods of underwater exploration as well as being a safety mechanism should the animal become disoriented. PMID:6757368

  17. Ontogeny of Oxygen Storage Capacity and Diving Ability in the Southern Sea Otter (Enhydra lutris nereis): Costs and Benefits of Large Lungs.

    PubMed

    Thometz, Nicole M; Murray, Michael J; Williams, Terrie M

    2015-01-01

    Small body size, large lungs, and dense pelage contribute to the unique challenges faced by diving sea otters (Enhydra lutris) when compared to other marine mammals. Here we determine the consequences of large lungs on the development of diving ability in southern sea otters (Enhydra lutris nereis) by examining the ontogeny of blood, muscle, and lung oxygen stores and calculating aerobic dive limits (cADL) for immature and mature age classes. Total oxygen storage capacity matures rapidly in sea otters, reaching adult levels by 2 mo postpartum. But this result is driven by exceptional lung capacity at birth, followed by a decrease in mass-specific lung volume with age. Blood and muscle oxygen stores remain well below adult values before weaning, with large pups exhibiting 74% and 54% of adult values, respectively. Slow muscle development limits the capacity of immature sea otters to dive against high positive buoyancy due to comparatively large lungs. Immature sea otters diving with total lung capacity (TLC) experience up to twice the mass-specific positive buoyancy as adults diving with TLC but can reduce these forces to comparable adult levels by using a smaller diving lung volume (DLV). The cADL of a juvenile with DLV is 3.62 min, while the cADL of an adult with TLC is 4.82 min. We find that the magnitude of positive buoyancy experienced by sea otters changes markedly with age and strongly influences the ontogeny of diving ability in this species. PMID:25860829

  18. Diving at altitude: from definition to practice.

    PubMed

    Egi, S Murat; Pieri, Massimo; Marroni, Alessandro

    2014-01-01

    Diving above sea level has different motivations for recreational, military, commercial and scientific activities. Despite the apparently wide practice of inland diving, there are three major discrepancies about diving at altitude: threshold elevation that requires changes in sea level procedures; upper altitude limit of the applicability of these modifications; and independent validation of altitude adaptation methods of decompression algorithms. The first problem is solved by converting the normal fluctuation in barometric pressure to an altitude equivalent. Based on the barometric variations recorded from a meteorological center, it is possible to suggest 600 meters as a threshold for classifying a dive as an "altitude" dive. The second problem is solved by proposing the threshold altitude of aviation (2,400 meters) to classify "high" altitude dives. The DAN (Divers Alert Network) Europe diving database (DB) is analyzed to solve the third problem. The database consists of 65,050 dives collected from different dive computers. A total of 1,467 dives were found to be classified as altitude dives. However, by checking the elevation according to the logged geographical coordinates, 1,284 dives were disqualified because the altitude setting had been used as a conservative setting by the dive computer despite the fact that the dive was made at sea level. Furthermore, according to the description put forward in this manuscript, 72 dives were disqualified because the surface level elevation is lower than 600 meters. The number of field data (111 dives) is still very low to use for the validation of any particular method of altitude adaptation concerning decompression algorithms. PMID:25562941

  19. The epidemiology of injury in scuba diving.

    PubMed

    Buzzacott, Peter L

    2012-01-01

    The epidemiology of injury associated with recreational scuba diving is reviewed. A search of electronic databases and reference lists identified pertinent research. Barotrauma, decompression sickness and drowning-related injuries were the most common morbidities associated with recreational scuba diving. The prevalence of incidents ranged from 7 to 35 injuries per 10,000 divers and from 5 to 152 injuries per 100,000 dives. Recreational scuba diving fatalities account for 0.013% of all-cause mortality aged ≥ 15 years. Drowning was the most common cause of death. Among treated injuries, recovery was complete in the majority of cases. Dive injuries were associated with diver-specific factors such as insufficient training and preexisting medical conditions. Environmental factors included air temperature and flying after diving. Dive-specific factors included loss of buoyancy control, rapid ascent and repetitive deep diving. The most common event to precede drowning was running out of gas (compressed air). Though diving injuries are relatively rare prospective, longitudinal studies are needed to quantify the effects of known risk factors and, indeed, asymptomatic injuries (e.g. brain lesions). Dive injury health economics data also remains wanting. Meanwhile, health promotion initiatives should continue to reinforce adherence to established safe diving practices such as observing depth/time limits, safety stops and conservative ascent rates. However, there is an obvious lack of evaluated diving safety interventions. PMID:22824839

  20. Effects of Rate-Limited Mass Transfer on Modeling Vapor Intrusion with Aerobic Biodegradation.

    PubMed

    Chen, Yiming; Hou, Deyi; Lu, Chunhui; Spain, Jim C; Luo, Jian

    2016-09-01

    Most of the models for simulating vapor intrusion accept the local equilibrium assumption for multiphase concentration distributions, that is, concentrations in solid, liquid and vapor phases are in equilibrium. For simulating vapor transport with aerobic biodegradation controlled by counter-diffusion processes, the local equilibrium assumption combined with dual-Monod kinetics and biomass decay may yield near-instantaneous behavior at steady state. The present research investigates how predicted concentration profiles and fluxes change as interphase mass transfer resistances are increased for vapor intrusion with aerobic biodegradation. Our modeling results indicate that the attenuation coefficients for cases with and without mass transfer limitations can be significantly different by orders of magnitude. Rate-limited mass transfer may lead to larger overlaps of contaminant vapor and oxygen concentrations, which cannot be simulated by instantaneous reaction models with local equilibrium mass transfer. In addition, the contaminant flux with rate-limited mass transfer is much smaller than that with local equilibrium mass transfer, indicating that local equilibrium mass transfer assumption may significantly overestimate the biodegradation rate and capacity for mitigating vapor intrusion through the unsaturated zone. Our results indicate a strong research need for field tests to examine the validity of local equilibrium mass transfer, a widely accepted assumption in modeling vapor intrusion. PMID:27486832

  1. Quantitative determinants of aerobic glycolysis identify flux through the enzyme GAPDH as a limiting step

    PubMed Central

    Shestov, Alexander A; Liu, Xiaojing; Ser, Zheng; Cluntun, Ahmad A; Hung, Yin P; Huang, Lei; Kim, Dongsung; Le, Anne; Yellen, Gary; Albeck, John G; Locasale, Jason W

    2014-01-01

    Aerobic glycolysis or the Warburg Effect (WE) is characterized by the increased metabolism of glucose to lactate. It remains unknown what quantitative changes to the activity of metabolism are necessary and sufficient for this phenotype. We developed a computational model of glycolysis and an integrated analysis using metabolic control analysis (MCA), metabolomics data, and statistical simulations. We identified and confirmed a novel mode of regulation specific to aerobic glycolysis where flux through GAPDH, the enzyme separating lower and upper glycolysis, is the rate-limiting step in the pathway and the levels of fructose (1,6) bisphosphate (FBP), are predictive of the rate and control points in glycolysis. Strikingly, negative flux control was found and confirmed for several steps thought to be rate-limiting in glycolysis. Together, these findings enumerate the biochemical determinants of the WE and suggest strategies for identifying the contexts in which agents that target glycolysis might be most effective. DOI: http://dx.doi.org/10.7554/eLife.03342.001 PMID:25009227

  2. [The heart and underwater diving].

    PubMed

    Lafay, V

    2006-11-01

    Cardiovascular examination of a certain number of candidates for underwater diving raises justifiable questions of aptitude. An indicative list of contraindications has been proposed by the French Federation of Underwater Studies and Sports but a physiopathological basis gives a better understanding of what is involved. During diving, the haemodynamic changes due not only to the exercise but also to cold immersion, hyperoxaemia and decompression impose the absence of any symptomatic cardiac disease. Moreover, the vasoconstriction caused by the cold and hyperoxaemia should incite great caution in both coronary and hypertensive patients. The contraindication related to betablocker therapy is controversial and the debate has not been settled in France. The danger of drowning makes underwater diving hazardous in all pathologies carrying a risk of syncope. Pacemaker patients should be carefully assessed and the depth of diving limited. Finally, the presence of right-to-left intracardiac shunts increases the risk of complications during decompressionand contraindicates underwater diving. Patent foramen ovale is a special case but no special investigation is required for its detection. The cardiologist examining candidates for underwater diving should take all these factors into consideration because, although underwater diving is a sport associated with an increased risk, each year there are more and more people, with differing degrees of aptitude, who wish to practice it. PMID:17181043

  3. Modeling the fate of particulate components in aerobic sludge stabilization--performance limitations.

    PubMed

    Özdemir, S; Çokgör, E U; Orhon, D

    2014-07-01

    The study investigated the effect of sludge composition on the limitations of aerobic stabilization. It was designed with the foresight that the stabilization mechanism could only be elucidated if the observed volatile suspended solids reduction were correlated with the fate of particulate components in sludge. Biomass sustained at sludge ages of 2 and 10 days were used in the stabilization reactors. Particulate components were determined by model evaluation of corresponding oxygen uptake rate profiles. Interpretation of the experimental data by modeling, based on death-regeneration mechanism without external substrate, could simulate the fate and evolution of major components in sludge during stabilization. It showed that both microbial decay and hydrolysis of non viable cellular material proceeded at much slower rates as compared with biological systems sustained with substrate feeding. Modeling also indicated that particulate metabolic products generated by sludge acclimated to high sludge age undergo slow biodegradation under prolonged stabilization. PMID:24865324

  4. Diving and foraging patterns of Marbled Murrelets (Brachyramphus marmoratus): Testing predictions from optimal-breathing models

    USGS Publications Warehouse

    Jodice, Patrick G.; Collopy, M.W.

    1999-01-01

    The diving behavior of Marbled Murrelets (Brachyramphus marmoratus) was studied using telemetry along the Oregon coast during the 1995 and 1996 breeding seasons and examined in relation to predictions from optimal-breathing models. Duration of dives, pauses, dive bouts, time spent under water during dive bouts, and nondiving intervals between successive dive bouts were recorded. Most diving metrics differed between years but not with oceanographic conditions or shore type. There was no effect of water depth on mean dive time or percent time spent under water even though dive bouts occurred in depths from 3 to 36 m. There was a significant, positive relationship between mean dive time and mean pause time at the dive-bout scale each year. At the dive-cycle scale, there was a significant positive relationship between dive time and preceding pause time in each year and a significant positive relationship between dive time and ensuing pause time in 1996. Although it appears that aerobic diving was the norm, there appeared to be an increase in anaerobic diving in 1996. The diving performance of Marbled Murrelets in this study appeared to be affected by annual changes in environmental conditions and prey resources but did not consistently fit predictions from optimal-breathing models.

  5. Introduction to Scuba Diving. Diver Education Series.

    ERIC Educational Resources Information Center

    Somers, Lee H.

    Scuba diving is often referred to as a "recreational sport." However, the term "sport" sometimes implies erroneous connotations and limits understanding. Scuba diving can be an avocation or a vocation. It is a pastime, a pursuit, or even a lifestyle, that can be as limited or extensive as one makes it. A persons level of commitment, degree of…

  6. Physiology of diving of birds and mammals.

    PubMed

    Butler, P J; Jones, D R

    1997-07-01

    This review concentrates on the physiological responses, and their control, in freely diving birds and mammals that enable them to remain submerged and sometimes quite active for extended periods of time. Recent developments in technology have provided much detailed information on the behavior of these fascinating animals. Unfortunately, the advances in technology have been insufficient to enable physiologists to obtain anything like the same level of detail on the metabolic rate and physiological adjustments that occur during natural diving. This has led to much speculation and calculations based on many assumptions concerning usable oxygen stores and metabolic rate during diving, in an attempt to explain the observed behavior. Despite their shortcomings, these calculations have provided useful insights into the degree of adaptations of various species of aquatic birds and mammals. Many of them, e.g., ducks, smaller penguins, fur seals, and Weddell seals, seem able to metabolize aerobically, when diving, at approximately the same (if not greater) rate as they do at the surface. Their enhanced oxygen stores are able to support aerobic metabolism, at what would not be considered unusually low levels, for the duration of the dives, although there are probably circulatory readjustments to ensure that the oxygen stores are managed judiciously. For other species, such as the larger penguins, South Georgian shag, and female elephant seals, there is a general consensus that they must either be reducing their aerobic metabolic rate when diving, possibly by way of regional hypothermia, and/or producing ATP, at least partly, by anaerobiosis and metabolizing the lactic acid when at the surface (although this is hardly likely in the case of the female elephant seals). Circulation is the proximate regulator of metabolism during aerobic diving, and heart rate is the best single indicator of circulatory adjustment. During voluntary dives, heart rates range from extreme

  7. Aerobic rice genotypes displayed greater adaptation to water-limited cultivation and tolerance to polyethyleneglycol-6000 induced stress.

    PubMed

    Sandhu, Nitika; Jain, Sunita; Battan, K R; Jain, R K

    2012-01-01

    Water scarcity and drought have seriously threatened traditional rice cultivation practices in several parts of the world including India. In the present investigation, experiments were conducted to see if the water-efficient aerobic rice genotypes developed at UAS, Bangalore (MAS25, MAS26 and MAS109) and IRRI, Philippines (MASARB25 and MASARB868), are endowed with drought tolerance or not. A set of these aerobic and five lowland high-yielding (HKR47 and PAU201, Taraori Basmati, Pusa1121 and Pusa1460) indica rice genotypes were evaluated for: (i) yield and yield components under submerged and aerobic conditions in field, (ii) root morphology and biomass under aerobic conditions in pots in the nethouse, (iii) PEG-6000 (0, -1, -2 and -3 bar) induced drought stress at vegetative stage using a hydroponic culture system and (iv) polymorphism for three SSR markers associated with drought resistance traits. Under submerged conditions, the yield of aerobic rice genotypes declined by 13.4-20.1 % whereas under aerobic conditions the yield of lowland indica/Basmati rice varieties declined by 23-27 %. Under water-limited conditions in pots, aerobic rice genotypes had 54-73.8 % greater root length and 18-60 % higher fresh root biomass compared to lowland indica rice varieties. Notably, root length of MASARB25 was 35 % shorter than MAS25 whereas fresh and dry root biomass of MASARB25 was 10 % and 64 % greater than MAS25. The lowland indica were more sensitive to PEG-stress with a score of 5.9-7.6 for Basmati and 6.1-6.7 for non-aromatic indica rice varieties, than the aerobic rice genotypes (score 2.7-3.3). A set of three microsatellite DNA markers (RM212, RM302 and RM3825) located on chromosome 1 which has been shown to be associated with drought resistance was investigated in the present study. Two of these markers (RM212 and RM302) amplified a specific allele in all the aerobic rice genotypes which were absent in lowland indica rice genotypes. PMID:23573038

  8. Rapid maturation of the muscle biochemistry that supports diving in Pacific walruses (Odobenus rosmarus divergens).

    PubMed

    Noren, Shawn R; Jay, Chadwick V; Burns, Jennifer M; Fischbach, Anthony S

    2015-10-01

    Physiological constraints dictate animals' ability to exploit habitats. For marine mammals, it is important to quantify physiological limits that influence diving and their ability to alter foraging behaviors. We characterized age-specific dive limits of walruses by measuring anaerobic (acid-buffering capacity) and aerobic (myoglobin content) capacities of the muscles that power hind (longissimus dorsi) and fore (supraspinatus) flipper propulsion. Mean buffering capacities were similar across muscles and age classes (a fetus, five neonatal calves, a 3 month old and 20 adults), ranging from 41.31 to 54.14 slykes and 42.00 to 46.93 slykes in the longissimus and supraspinatus, respectively. Mean myoglobin in the fetus and neonatal calves fell within a narrow range (longissimus: 0.92-1.68 g 100 g(-1) wet muscle mass; supraspinatus: 0.88-1.64 g 100 g(-1) wet muscle mass). By 3 months post-partum, myoglobin in the longissimus increased by 79%, but levels in the supraspinatus remained unaltered. From 3 months post-partum to adulthood, myoglobin increased by an additional 26% in the longissimus and increased by 126% in the supraspinatus; myoglobin remained greater in the longissimus compared with the supraspinatus. Walruses are unique among marine mammals because they are born with a mature muscle acid-buffering capacity and attain mature myoglobin content early in life. Despite rapid physiological development, small body size limits the diving capacity of immature walruses and extreme sexual dimorphism reduces the diving capacity of adult females compared with adult males. Thus, free-ranging immature walruses likely exhibit the shortest foraging dives while adult males are capable of the longest foraging dives. PMID:26347559

  9. Rapid maturation of the muscle biochemistry that supports diving in Pacific walruses (Odobenus rosmarus divergens)

    USGS Publications Warehouse

    Norem, Shawn R.; Jay, Chadwick V.; Burns, Jennifer M.; Fischbach, Anthony S.

    2015-01-01

    Physiological constraints dictate animals’ ability to exploit habitats. For marine mammals, it is important to quantify physiological limits that influence diving and their ability to alter foraging behaviors. We characterized age-specific dive limits of walruses by measuring anaerobic (acid-buffering capacity) and aerobic (myoglobin content) capacities of the muscles that power hind (longissimus dorsi) and fore (supraspinatus) flipper propulsion. Mean buffering capacities were similar across muscles and age classes (a fetus, five neonatal calves, a 3 month old and 20 adults), ranging from 41.31 to 54.14 slykes and 42.00 to 46.93 slykes in the longissimus and supraspinatus, respectively. Mean myoglobin in the fetus and neonatal calves fell within a narrow range (longissimus: 0.92–1.68 g 100 g−1 wet muscle mass; supraspinatus: 0.88–1.64 g 100 g−1 wet muscle mass). By 3 months post-partum, myoglobin in the longissimus increased by 79%, but levels in the supraspinatus remained unaltered. From 3 months post-partum to adulthood, myoglobin increased by an additional 26% in the longissimus and increased by 126% in the supraspinatus; myoglobin remained greater in the longissimus compared with the supraspinatus. Walruses are unique among marine mammals because they are born with a mature muscle acid-buffering capacity and attain mature myoglobin content early in life. Despite rapid physiological development, small body size limits the diving capacity of immature walruses and extreme sexual dimorphism reduces the diving capacity of adult females compared with adult males. Thus, free-ranging immature walruses likely exhibit the shortest foraging dives while adult males are capable of the longest foraging dives.

  10. Metabolic regulation in diving birds and mammals.

    PubMed

    Butler, Patrick J

    2004-08-12

    Ducks, fur seals, Weddell seals and probably most cetaceans seem to be able to dive and remain aerobic for durations that are consistent with their elevated stores of usable oxygen and their metabolic rate while diving being similar to that when they are resting at the surface of the water. Ducks, in fact, have a high metabolic rate while diving, mainly because of their large positive buoyancy, but other species have relatively low buoyancy, are better streamlined and use lift-based rather than drag-based propulsion. However, species such as the larger penguins, grey seals and elephant seals seem to achieve the impossible by performing a substantial proportion of their dives for periods longer than would be expected on the above assumptions, and yet remaining aerobic. The logical conclusion is that during such dives these species reduce their metabolic rate below the resting level (hypometabolism) and, in some of them, there is a regional reduction in body temperature (hypothermia) which may contribute to the reduction in metabolic rate. PMID:15288601

  11. 29 CFR 1910.426 - Mixed-gas diving.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... fsw or when the dive involves inwater decompression time of greater than 120 minutes, except when... depths greater than 300 fsw, except when diving is conducted in physically confining spaces. (c... for dives deeper than 100 fsw or outside the no-decompression limits. (8) When a closed bell is...

  12. 29 CFR 1910.426 - Mixed-gas diving.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... fsw or when the dive involves inwater decompression time of greater than 120 minutes, except when... depths greater than 300 fsw, except when diving is conducted in physically confining spaces. (c... for dives deeper than 100 fsw or outside the no-decompression limits. (8) When a closed bell is...

  13. 29 CFR 1910.426 - Mixed-gas diving.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... fsw or when the dive involves inwater decompression time of greater than 120 minutes, except when... depths greater than 300 fsw, except when diving is conducted in physically confining spaces. (c... for dives deeper than 100 fsw or outside the no-decompression limits. (8) When a closed bell is...

  14. Growth of Aerobic Ripening Bacteria at the Cheese Surface Is Limited by the Availability of Iron

    PubMed Central

    Back, Alexandre; Irlinger, Françoise

    2012-01-01

    The microflora on the surface of smear-ripened cheeses is composed of various species of bacteria and yeasts that contribute to the production of the desired organoleptic properties. The objective of the present study was to show that iron availability is a limiting factor in the growth of typical aerobic ripening bacteria in cheese. For that purpose, we investigated the effect of iron or siderophore addition in model cheeses that were coinoculated with a yeast and a ripening bacterium. Both iron and the siderophore desferrioxamine B stimulated the growth of ripening bacteria belonging to the genera Arthrobacter, Corynebacterium, and Brevibacterium. The extent of stimulation was strain dependent, and generally, the effect of desferrioxamine B was greater than that of iron. Measurements of the expression of genes related to the metabolism of iron by Arthrobacter arilaitensis Re117 by real-time reverse transcription-PCR showed that these genes were transcribed during growth in cheese. The addition of desferrioxamine B increased the expression of two genes encoding iron-siderophore ABC transport binding proteins. The addition of iron decreased the expression of siderophore biosynthesis genes and of part of the genes encoding iron-siderophore ABC transport components. It was concluded that iron availability is a limiting factor in the growth of typical cheese surface bacteria. The selection of strains with efficient iron acquisition systems may be useful for the development of defined-strain surface cultures. Furthermore, the importance of iron metabolism in the microbial ecology of cheeses should be investigated since it may result in positive or negative microbial interactions. PMID:22367081

  15. Diving Medicine: Frequently Asked Questions

    MedlinePlus

    ... re-evaluating your fitness to dive. Thyroid Conditions Fitness to Dive Asthma and Scuba Diving Bone Considerations ... Healthy, But Overweight DAN Discusses the Issue of Fitness and Diving By Joel Dovenbarger, Vice President, DAN ...

  16. Transport and metabolism of fumaric acid in Saccharomyces cerevisiae in aerobic glucose-limited chemostat culture.

    PubMed

    Shah, Mihir V; van Mastrigt, Oscar; Heijnen, Joseph J; van Gulik, Walter M

    2016-04-01

    Currently, research is being focused on the industrial-scale production of fumaric acid and other relevant organic acids from renewable feedstocks via fermentation, preferably at low pH for better product recovery. However, at low pH a large fraction of the extracellular acid is present in the undissociated form, which is lipophilic and can diffuse into the cell. There have been no studies done on the impact of high extracellular concentrations of fumaric acid under aerobic conditions in S. cerevisiae, which is a relevant issue to study for industrial-scale production. In this work we studied the uptake and metabolism of fumaric acid in S. cerevisiae in glucose-limited chemostat cultures at a cultivation pH of 3.0 (pH < pK). Steady states were achieved with different extracellular levels of fumaric acid, obtained by adding different amounts of fumaric acid to the feed medium. The experiments were carried out with the wild-type S. cerevisiae CEN.PK 113-7D and an engineered S. cerevisiae ADIS 244 expressing a heterologous dicarboxylic acid transporter (DCT-02) from Aspergillus niger, to examine whether it would be capable of exporting fumaric acid. We observed that fumaric acid entered the cells most likely via passive diffusion of the undissociated form. Approximately two-thirds of the fumaric acid in the feed was metabolized together with glucose. From metabolic flux analysis, an increased ATP dissipation was observed only at high intracellular concentrations of fumarate, possibly due to the export of fumarate via an ABC transporter. The implications of our results for the industrial-scale production of fumaric acid are discussed. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26683700

  17. Physiological control of diving behaviour in the Weddell seal Leptonychotes weddelli: a model based on cardiorespiratory control theory.

    PubMed

    Stephenson, Richard

    2005-05-01

    Despite being obligate air breathers, many species of marine mammal are capable of spending most of their lives submerged in water. How they do this has been a subject of intense interest to physiologists for over a century, yet we still do not have a detailed understanding of the physiological mechanisms underlying this behaviour. What are the proximate mechanisms that trigger the 'decisions' to submerge and return to the surface? The present study proposes a model intended to address this question, based on fundamental concepts of cardiorespiratory control. Two basic hypotheses are examined by computer simulation, using a mathematical model of the mammalian cardiorespiratory control system with parameter values for an adult Weddell seal: (1) that the control of diving can be considered to be a respiratory control problem, and (2) that dives are initiated and maintained by disfacilitation of respiratory drive, not inhibition. Computer simulations confirmed the plausibility of these hypotheses. Simulated diving behaviour and physiological responses (ventilation, cardiac output, blood and tissue gas tensions) were consistent with published data from freely diving Weddell seals. Dives up to the estimated aerobic dive limit (ADL, 18-25 min) could be simulated without the need for active inhibition of breathing in this model. This theoretical analysis suggests that the most important physiological adjustments occur during the surface interval phase of the dive cycle and include hyperventilation accompanied by high cardiac output, appropriate regulation of cerebral blood flow and central chemoreceptor threshold shifts. During dives, cardiac output, distribution of peripheral blood flow, splenic contraction and peripheral chemoreflex drives were found to modulate physiological and behavioural responses, but were not essential for simulated dives to occur. The main conclusion from this study is that the central chemoreceptor may be an important mechanism involved in the

  18. When surfacers do not dive: multiple significance of extended surface times in marine turtles.

    PubMed

    Hochscheid, S; Bentivegna, F; Hamza, A; Hays, G C

    2010-04-01

    Marine turtles spend more than 90% of their life underwater and have been termed surfacers as opposed to divers. Nonetheless turtles have been reported occasionally to float motionless at the surface but the reasons for this behaviour are not clear. We investigated the location, timing and duration of extended surface times (ESTs) in 10 free-ranging loggerhead turtles (Caretta caretta) and the possible relationship to water temperature and diving activity recorded via satellite relay data loggers for 101-450 days. For one turtle that dived only in offshore areas, ESTs contributed 12% of the time whereas for the other turtles ESTs contributed 0.4-1.8% of the time. ESTs lasted on average 90 min but were mostly infrequent and irregular, excluding the involvement of a fundamental regulatory function. However, 82% of the ESTs occurred during daylight, mostly around noon, suggesting a dependence on solar radiation. For three turtles, there was an appreciable (7 degrees C to 10.5 degrees C) temperature decrease with depth for dives during periods when ESTs occurred frequently, suggesting a re-warming function of EST to compensate for decreased body temperatures, possibly to enhance digestive efficiency. A positive correlation between body mass and EST duration supported this explanation. By contrast, night-active turtles that exceeded their calculated aerobic dive limits in 7.6-16% of the dives engaged in nocturnal ESTs, probably for lactate clearance. This is the first evidence that loggerhead turtles may refrain from diving for at least two reasons, either to absorb solar radiation or to recover from anaerobic activity. PMID:20348345

  19. Experimental Limiting Oxygen Concentrations for Nine Organic Solvents at Temperatures and Pressures Relevant to Aerobic Oxidations in the Pharmaceutical Industry

    PubMed Central

    2015-01-01

    Applications of aerobic oxidation methods in pharmaceutical manufacturing are limited in part because mixtures of oxygen gas and organic solvents often create the potential for a flammable atmosphere. To address this issue, limiting oxygen concentration (LOC) values, which define the minimum partial pressure of oxygen that supports a combustible mixture, have been measured for nine commonly used organic solvents at elevated temperatures and pressures. The solvents include acetic acid, N-methylpyrrolidone, dimethyl sulfoxide, tert-amyl alcohol, ethyl acetate, 2-methyltetrahydrofuran, methanol, acetonitrile, and toluene. The data obtained from these studies help define safe operating conditions for the use of oxygen with organic solvents. PMID:26622165

  20. Preparing Muscles for Diving: Age-Related Changes in Muscle Metabolic Profiles in Harp (Pagophilus groenlandicus) and Hooded (Cystophora cristata) Seals.

    PubMed

    Burns, J M; Lestyk, K; Freistroffer, D; Hammill, M O

    2015-01-01

    In adult marine mammals, muscles can sustain aerobic metabolism during dives in part because they contain large oxygen (O2) stores and metabolic rates are low. However, young pups have significantly lower tissue O2 stores and much higher mass-specific metabolic rates. To investigate how these differences may influence muscle function during dives, we measured the activities of enzymes involved in aerobic and anaerobic metabolic pathways (citrate synthase [CS], β-hydroxyacyl-coenzyme A dehydrogenase [HOAD], lactate dehydrogenase [LDH]) and the LDH isoform profile in six muscles from 41 harp (Pagophilus groenlandicus) and 30 hooded (Cystophora cristata) seals ranging in age from fetal to adult. All neonatal muscles had significantly higher absolute but lower metabolically scaled CS and HOAD activities than adults (∼ 70% and ∼ 85% lower, respectively). Developmental increases in LDH activity lagged that of aerobic enzymes and were not accompanied by changes in isozyme profile, suggesting that changes in enzyme concentration rather than structure determine activity levels. Biochemical maturation proceeded faster in the major locomotory muscles. In combination, findings suggest that pup muscles are unable to support strenuous aerobic exercise or rely heavily on anaerobic metabolism during early diving activities and that pups' high mass-specific metabolic rates may play a key role in limiting the ability of their muscles to support underwater foraging. PMID:25730272

  1. Pulmonary function in children after open water SCUBA dives.

    PubMed

    Winkler, B E; Tetzlaff, K; Muth, C-M; Hebestreit, H

    2010-10-01

    An increasing number of children and adolescents is diving with Self-Contained Underwater Breathing Apparatus (SCUBA). SCUBA diving is associated with health risks such as pulmonary barotrauma, especially in children and in individuals with airflow limitation. As no data has been published on the effects of open-water diving on pulmonary function in children, the objective of this study was to evaluate the effects of SCUBA dives on airflow in children. 16 healthy children aged 10-13 years underwent spirometry and a cycle-exercise challenge while breathing cold air. They subsequently performed dives to 1-m and 8-m depth in random order. Pulmonary function was measured before and after the exercise challenge and the dives. There were statistically significant decreases in FEV1, FVC, FEV1/FVC, MEF25 and MEF50 after the cold-air exercise challenge and the dives. Changes in lung function following the exercise challenge did not predict the responses to SCUBA diving. In 3 children the post-dive decrements in FEV1 exceeded 10%. These children had a lower body weight and BMI percentile. SCUBA diving in healthy children may be associated with relevant airflow limitation. A low body mass might contribute to diving-associated bronchoconstriction. In the majority of subjects, no clinically relevant airway obstruction could be observed. PMID:20677123

  2. [Lungs et diving].

    PubMed

    Héritier, F; Avanzi, P; Nicod, L

    2014-11-19

    Whilst underwater, the body is submitted to significant variations of the surrounding pressure according to the depth. These conditions modify the hemodynamic and the ventilatory mechanics considerably. Some repercussions, like pulmonary barotrauma, are related to simple physical phenomena. Others, like decompression sickness, are due to more com- plex processes. Breath-hold diving disrupts haematosis and can be complicated by alveolar haemorrhage and loss of consciousness. Acute pulmonary oedema during scuba-diving, breath-hold diving and swimming has been reported more recently. In case of pulmonary disorders scuba-diving is contraindicated most of the time. It is therefore highly recommended to seek medical advice to prevent problems. PMID:25603564

  3. Deep-diving dinosaurs

    NASA Astrophysics Data System (ADS)

    Hayman, John

    2012-08-01

    Dysbaric bone necrosis demonstrated in ichthyosaurs may be the result of prolonged deep diving rather than rapid ascent to escape predators. The bone lesions show structural and anatomical similarity to those that may occur in human divers and in the deep diving sperm whale, Physeter macrocephalus.

  4. Deep-diving dinosaurs.

    PubMed

    Hayman, John

    2012-08-01

    Dysbaric bone necrosis demonstrated in ichthyosaurs may be the result of prolonged deep diving rather than rapid ascent to escape predators. The bone lesions show structural and anatomical similarity to those that may occur in human divers and in the deep diving sperm whale, Physeter macrocephalus. PMID:22824942

  5. Diving and hyperbaric ophthalmology.

    PubMed

    Butler, F K

    1995-01-01

    Exposure of the human body to ambient pressures greater than that at sea level may result in various disorders, some of which have ocular manifestations. Additionally, some eye disorders and postoperative states may be adversely affected by the underwater environment or other hyperbaric exposures. The prevalence of recreational, military, and commercial diving, as well as the medical use of hyperbaric oxygen therapy, requires that ophthalmologists be familiar with the effects of the hyperbaric environment on the normal and diseased eye. The ophthalmology and diving medical literatures were surveyed for publications relating to the ophthalmic aspects of diving and hyperbaric exposures. Underwater optics, underwater refractive correction, and ophthalmic aspects of a fitness-to-dive evaluation are summarized. The evaluation and management of ocular manifestations of decompression sickness and arterial gas embolism are reviewed and guidelines for diving after ocular surgery are proposed. PMID:7604359

  6. High-altitude diving in river otters: coping with combined hypoxic stresses

    PubMed Central

    Crait, Jamie R.; Prange, Henry D.; Marshall, Noah A.; Harlow, Henry J.; Cotton, Clark J.; Ben-David, Merav

    2012-01-01

    SUMMARY River otters (Lontra canadensis) are highly active, semi-aquatic mammals indigenous to a range of elevations and represent an appropriate model for assessing the physiological responses to diving at altitude. In this study, we performed blood gas analyses and compared blood chemistry of river otters from a high-elevation (2357 m) population at Yellowstone Lake with a sea-level population along the Pacific coast. Comparisons of oxygen dissociation curves (ODC) revealed no significant difference in hemoglobin-oxygen (Hb-O2) binding affinity between the two populations - potentially because of demands for tissue oxygenation. Instead, high-elevation otters had greater Hb concentrations (18.7 g dl-1) than sea-level otters (15.6 g dl-1). Yellowstone otters displayed higher levels of the vasodilator nitric oxide (NO), and half the concentration of the serum protein albumin, possibly to compensate for increased blood viscosity. Despite compensation in several hematological and serological parameters, theoretical aerobic dive limits (ADL) were similar between high-elevation and sea-level otters because of the lower availability of O2 at altitude. Our results suggest that recent disruptions to the Yellowstone Lake food web could be detrimental to otters because at this high elevation, constraints on diving may limit their ability to switch to prey in a deep-water environment. PMID:22189769

  7. Recreational technical diving part 1: an introduction to technical diving methods and activities.

    PubMed

    Mitchell, Simon J; Doolette, David J

    2013-06-01

    Technical divers use gases other than air and advanced equipment configurations to conduct dives that are deeper and/or longer than typical recreational air dives. The use of oxygen-nitrogen (nitrox) mixes with oxygen fractions higher than air results in longer no-decompression limits for shallow diving, and faster decompression from deeper dives. For depths beyond the air-diving range, technical divers mix helium, a light non-narcotic gas, with nitrogen and oxygen to produce 'trimix'. These blends are tailored to the depth of intended use with a fraction of oxygen calculated to produce an inspired oxygen partial pressure unlikely to cause cerebral oxygen toxicity and a nitrogen fraction calculated to produce a tolerable degree of nitrogen narcosis. A typical deep technical dive will involve the use of trimix at the target depth with changes to gases containing more oxygen and less inert gas during the decompression. Open-circuit scuba may be used to carry and utilise such gases, but this is very wasteful of expensive helium. There is increasing use of closed-circuit 'rebreather' devices. These recycle expired gas and potentially limit gas consumption to a small amount of inert gas to maintain the volume of the breathing circuit during descent and the amount of oxygen metabolised by the diver. This paper reviews the basic approach to planning and execution of dives using these methods to better inform physicians of the physical demands and risks. PMID:23813462

  8. Decompression sickness following breath-hold diving.

    PubMed

    Schipke, J D; Gams, E; Kallweit, Oliver

    2006-01-01

    Despite convincing evidence of a relationship between breath-hold diving and decompression sickness (DCS), the causal connection is only slowly being accepted. Only the more recent textbooks have acknowledged the risks of repetitive breath-hold diving. We compare four groups of breath-hold divers: (1) Japanese and Korean amas and other divers from the Pacific area, (2) instructors at naval training facilities, (3) spear fishers, and (4) free-dive athletes. While the number of amas is likely decreasing, and Scandinavian Navy training facilities recorded only a few accidents, the number of spear fishers suffering accidents is on the rise, in particular during championships or using scooters. Finally, national and international associations (e.g., International Association of Free Drives [IAFD] or Association Internationale pour Le Developpment De L'Apnee [AIDA]) promote free-diving championships including deep diving categories such as constant weight, variable weight, and no limit. A number of free-diving athletes, training for or participating in competitions, are increasingly accident prone as the world record is presently set at a depth of 171 m. This review presents data found after searching Medline and ISI Web of Science and using appropriate Internet search engines (e.g., Google). We report some 90 cases in which DCS occurred after repetitive breath-hold dives. Even today, the risk of suffering from DCS after repetitive breath-hold diving is often not acknowledged. We strongly suggest that breath-hold divers and their advisors and physicians be made aware of the possibility of DCS and of the appropriate therapeutic measures to be taken when DCS is suspected. Because the risk of suffering from DCS increases depending on depth, bottom time, rate of ascent, and duration of surface intervals, some approaches to assess the risks are presented. Regrettably, none of these approaches is widely accepted. We propose therefore the development of easily manageable

  9. Wingate test performance in children with asthma: aerobic or anaerobic limitation?

    PubMed

    Counil, F P; Varray, A; Karila, C; Hayot, M; Voisin, M; Préfaut, C

    1997-04-01

    To investigate the anaerobic capacity in children with bronchial asthma, eight male children with atopic asthma (age: 12 +/- 1.7 yr) and seven healthy control subjects (age: 12 +/- 1 yr) performed a 30-s all-out exercise test: the Wingate anaerobic test (WanT). Post-exercise plasma epinephrine (E), norepinephrine (NE), venous blood lactate (La), and blood pH levels were determined. Peak power (Ppeak), mean power (Pm), and total energy expenditure (Wtot) during the WanT were assessed. The relative importance of aerobic (WO2) and anaerobic (Wana) energy release during the WanT was also evaluated. In comparison with control subjects, the children with asthma exhibited lower Ppeak (W.kg-1): 6 +/- 1.14 vs 7.3 +/- 0.5, P < 0.05; lower Pm (W.kg-1): 4.7 +/- 0.8 vs 5.9 +/- 0.5, P < 0.05; and lower Wtot (Jg-1): 140.3 +/- 25 vs 176.9 +/- 19, P < 0.05. The relative contribution of WO2 (26%) and Wana (74%) to the Wtot was identical in both groups. Blood lactate and pH kinetics revealed significantly lower La values and less acidosis in the asthmatic group (P < 0.001). Lastly, E (pg.ml-1) concentrations were lower in the asthmatic group: 274.96 +/- 84.58 vs 901.28 +/- 604.76, P < 0.05. These results suggest a reduced anaerobic capacity in children with asthma. A diminished adrenergic response to exhausting exercise, leading to a decreased anaerobic glycolysis, could partly account for this phenomenon. PMID:9107623

  10. Diving dynamics of seabirds

    NASA Astrophysics Data System (ADS)

    Jung, Sunghwan; Chang, Brian; Croson, Matt; Straker, Lorian; Dove, Carla

    2015-03-01

    Diving is the activity of falling from air into water, which is somewhat dangerous due to the impact. Humans dive for entertainments less than 20 meters high, however seabirds dive as a hunting mechanism from more than 20 meters high. Moreover, most birds including seabirds have a slender and long neck compared to many other animals, which can potentially be the weakest part of the body upon axial impact compression. Motivated by the diving dynamics, we investigate the effect of surface and geometric configurations on structures consisting of a beak-like cone and a neck-like elastic beam. A transition from non-buckling to buckling is characterized and understood through physical experiments and an analytical model.

  11. 29 CFR 1910.423 - Post-dive procedures.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... no-decompression limits, deeper than 100 fsw or using mixed gas as a breathing mixture, the employer... the surface to a minimum of 165 fsw (6 ATA) shall be available at the dive location for: (i) Surface-supplied air diving to depths deeper than 100 fsw and shallower than 220 fsw; (ii) Mixed gas...

  12. Saturation diving; physiology and pathophysiology.

    PubMed

    Brubakk, Alf O; Ross, John A S; Thom, Stephen R

    2014-07-01

    In saturation diving, divers stay under pressure until most of their tissues are saturated with breathing gas. Divers spend a long time in isolation exposed to increased partial pressure of oxygen, potentially toxic gases, bacteria, and bubble formation during decompression combined with shift work and long periods of relative inactivity. Hyperoxia may lead to the production of reactive oxygen species (ROS) that interact with cell structures, causing damage to proteins, lipids, and nucleic acid. Vascular gas-bubble formation and hyperoxia may lead to dysfunction of the endothelium. The antioxidant status of the diver is an important mechanism in the protection against injury and is influenced both by diet and genetic factors. The factors mentioned above may lead to production of heat shock proteins (HSP) that also may have a negative effect on endothelial function. On the other hand, there is a great deal of evidence that HSPs may also have a "conditioning" effect, thus protecting against injury. As people age, their ability to produce antioxidants decreases. We do not currently know the capacity for antioxidant defense, but it is reasonable to assume that it has a limit. Many studies have linked ROS to disease states such as cancer, insulin resistance, diabetes mellitus, cardiovascular diseases, and atherosclerosis as well as to old age. However, ROS are also involved in a number of protective mechanisms, for instance immune defense, antibacterial action, vascular tone, and signal transduction. Low-grade oxidative stress can increase antioxidant production. While under pressure, divers change depth frequently. After such changes and at the end of the dive, divers must follow procedures to decompress safely. Decompression sickness (DCS) used to be one of the major causes of injury in saturation diving. Improved decompression procedures have significantly reduced the number of reported incidents; however, data indicate considerable underreporting of injuries

  13. Gait switches in deep-diving beaked whales: biomechanical strategies for long-duration dives.

    PubMed

    Martín López, Lucía Martina; Miller, Patrick J O; Aguilar de Soto, Natacha; Johnson, Mark

    2015-05-01

    Diving animals modulate their swimming gaits to promote locomotor efficiency and so enable longer, more productive dives. Beaked whales perform extremely long and deep foraging dives that probably exceed aerobic capacities for some species. Here, we use biomechanical data from suction-cup tags attached to three species of beaked whales (Mesoplodon densirostris, N=10; Ziphius cavirostris, N=9; and Hyperoodon ampullatus, N=2) to characterize their swimming gaits. In addition to continuous stroking and stroke-and-glide gaits described for other diving mammals, all whales produced occasional fluke-strokes with distinctly larger dorso-ventral acceleration, which we termed 'type-B' strokes. These high-power strokes occurred almost exclusively during deep dive ascents as part of a novel mixed gait. To quantify body rotations and specific acceleration generated during strokes we adapted a kinematic method combining data from two sensors in the tag. Body rotations estimated with high-rate magnetometer data were subtracted from accelerometer data to estimate the resulting surge and heave accelerations. Using this method, we show that stroke duration, rotation angle and acceleration were bi-modal for these species, with B-strokes having 76% of the duration, 52% larger body rotation and four times more surge than normal strokes. The additional acceleration of B-strokes did not lead to faster ascents, but rather enabled brief glides, which may improve the overall efficiency of this gait. Their occurrence towards the end of long dives leads us to propose that B-strokes may recruit fast-twitch fibres that comprise ∼80% of swimming muscles in Blainville's beaked whales, thus prolonging foraging time at depth. PMID:25954042

  14. DIVING ENERGETICS IN LESSER SCAUP (AYTHYTA AFFINIS, EYTON)

    PubMed

    Stephenson

    1994-05-01

    Mechanical and aerobic energy costs of diving were measured simultaneously by closed-circuit respirometry in six lesser scaup Aythya affinis Eyton (body mass=591±30 g) during bouts of voluntary feeding dives. Durations of dives (td=13.5±1.4 s) and surface intervals (ti=16.3±2.2 s) were within the normal range for ducks diving to 1.5 m depth. Mechanical power output (3.69±0.24 W kg-1) and aerobic power input (29.32±2.47 W kg-1) were both higher than previous estimates. Buoyancy was found to be the dominant factor determining dive costs, contributing 62 % of the mechanical cost of descent and 87 % of the cost of staying at the bottom while feeding. Drag forces, including the contribution from the forward-moving hindlimbs during the recovery stroke of the leg-beat cycle, contributed 27 % and 13 % of the mechanical costs of descent and feeding, respectively. Inertial forces created by net acceleration during descent contributed approximately 11 % during descent but not at all during the feeding phase. Buoyant force at the start of voluntary dives (6.2±0.35 N kg-1) was significantly greater than that measured in restrained ducks (4.9±0.2 N kg-1). Loss of air from the plumage layer and compression due to hydrostatic pressure decreased buoyancy by 32 %. Mechanical work and power output were 1.9 and 2.4 times greater during descent than during the feeding phase. Therefore, energetic costs are strongly affected by dive-phase durations. Estimates by unsteady and steady biomechanical models differ significantly during descent but not during the feeding phase. PMID:9317536

  15. Diving fatality investigations: recent changes.

    PubMed

    Edmonds, Carl; Caruso, James

    2014-06-01

    Modifications to the investigation procedures in diving fatalities have been incorporated into the data acquisition by diving accident investigators. The most germane proposal for investigators assessing diving fatalities is to delay the drawing of conclusions until all relevant diving information is known. This includes: the accumulation and integration of the pathological data; the access to dive computer information; re-enactments of diving incidents; post-mortem CT scans and the interpretation of intravascular and tissue gas detected. These are all discussed, with reference to the established literature and recent publications. PMID:24986727

  16. A comparative meta-analysis of maximal aerobic metabolism of vertebrates: implications for respiratory and cardiovascular limits to gas exchange.

    PubMed

    Hillman, Stanley S; Hancock, Thomas V; Hedrick, Michael S

    2013-02-01

    Maximal aerobic metabolic rates (MMR) in vertebrates are supported by increased conductive and diffusive fluxes of O(2) from the environment to the mitochondria necessitating concomitant increases in CO(2) efflux. A question that has received much attention has been which step, respiratory or cardiovascular, provides the principal rate limitation to gas flux at MMR? Limitation analyses have principally focused on O(2) fluxes, though the excess capacity of the lung for O(2) ventilation and diffusion remains unexplained except as a safety factor. Analyses of MMR normally rely upon allometry and temperature to define these factors, but cannot account for much of the variation and often have narrow phylogenetic breadth. The unique aspect of our comparative approach was to use an interclass meta-analysis to examine cardio-respiratory variables during the increase from resting metabolic rate to MMR among vertebrates from fish to mammals, independent of allometry and phylogeny. Common patterns at MMR indicate universal principles governing O(2) and CO(2) transport in vertebrate cardiovascular and respiratory systems, despite the varied modes of activities (swimming, running, flying), different cardio-respiratory architecture, and vastly different rates of metabolism (endothermy vs. ectothermy). Our meta-analysis supports previous studies indicating a cardiovascular limit to maximal O(2) transport and also implicates a respiratory system limit to maximal CO(2) efflux, especially in ectotherms. Thus, natural selection would operate on the respiratory system to enhance maximal CO(2) excretion and the cardiovascular system to enhance maximal O(2) uptake. This provides a possible evolutionary explanation for the conundrum of why the respiratory system appears functionally over-designed from an O(2) perspective, a unique insight from previous work focused solely on O(2) fluxes. The results suggest a common gas transport blueprint, or Bauplan, in the vertebrate clade. PMID

  17. [Case report: fatal diving-accident. Or: accident while diving?].

    PubMed

    Böttcher, F; Jüttner, B; Krause, A; Rocha, M; Koppert, W

    2012-02-01

    This example of a fatal diving accident shows how challenging such cases can be in pre-hospital and clinical care. There is no common mechanism in diving fatalities and more than one group of disorders coming along with decompression sickness. Diving medicine is not an element of medical education, which results in insecurity and hampers adequate therapy of diving incidents. This is aggravated by an insufficient availability of hyperbaric chambers in Germany. PMID:22354401

  18. 46 CFR 197.410 - Dive procedures.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... GENERAL PROVISIONS Commercial Diving Operations Operations § 197.410 Dive procedures. (a) The diving supervisor shall insure that— (1) Before commencing diving operations, dive team members are briefed on— (i... safety of the diving operation; and (iii) Any modifications to the operations manual or...

  19. 46 CFR 197.460 - Diving equipment.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Diving equipment. 197.460 Section 197.460 Shipping COAST... GENERAL PROVISIONS Commercial Diving Operations Periodic Tests and Inspections of Diving Equipment § 197.460 Diving equipment. The diving supervisor shall insure that the diving equipment designated for...

  20. 46 CFR 197.430 - SCUBA diving.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false SCUBA diving. 197.430 Section 197.430 Shipping COAST... GENERAL PROVISIONS Commercial Diving Operations Specific Diving Mode Procedures § 197.430 SCUBA diving. The diving supervisor shall insure that— (a) SCUBA diving is not conducted— (1) Outside the...

  1. 46 CFR 197.460 - Diving equipment.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Diving equipment. 197.460 Section 197.460 Shipping COAST... GENERAL PROVISIONS Commercial Diving Operations Periodic Tests and Inspections of Diving Equipment § 197.460 Diving equipment. The diving supervisor shall insure that the diving equipment designated for...

  2. 46 CFR 197.430 - SCUBA diving.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false SCUBA diving. 197.430 Section 197.430 Shipping COAST... GENERAL PROVISIONS Commercial Diving Operations Specific Diving Mode Procedures § 197.430 SCUBA diving. The diving supervisor shall insure that— (a) SCUBA diving is not conducted— (1) Outside the...

  3. 46 CFR 197.460 - Diving equipment.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Diving equipment. 197.460 Section 197.460 Shipping COAST... GENERAL PROVISIONS Commercial Diving Operations Periodic Tests and Inspections of Diving Equipment § 197.460 Diving equipment. The diving supervisor shall insure that the diving equipment designated for...

  4. 46 CFR 197.460 - Diving equipment.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Diving equipment. 197.460 Section 197.460 Shipping COAST... GENERAL PROVISIONS Commercial Diving Operations Periodic Tests and Inspections of Diving Equipment § 197.460 Diving equipment. The diving supervisor shall insure that the diving equipment designated for...

  5. 46 CFR 197.460 - Diving equipment.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Diving equipment. 197.460 Section 197.460 Shipping COAST... GENERAL PROVISIONS Commercial Diving Operations Periodic Tests and Inspections of Diving Equipment § 197.460 Diving equipment. The diving supervisor shall insure that the diving equipment designated for...

  6. 46 CFR 197.430 - SCUBA diving.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false SCUBA diving. 197.430 Section 197.430 Shipping COAST... GENERAL PROVISIONS Commercial Diving Operations Specific Diving Mode Procedures § 197.430 SCUBA diving. The diving supervisor shall insure that— (a) SCUBA diving is not conducted— (1) Outside the...

  7. 46 CFR 197.430 - SCUBA diving.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false SCUBA diving. 197.430 Section 197.430 Shipping COAST... GENERAL PROVISIONS Commercial Diving Operations Specific Diving Mode Procedures § 197.430 SCUBA diving. The diving supervisor shall insure that— (a) SCUBA diving is not conducted— (1) Outside the...

  8. 46 CFR 197.430 - SCUBA diving.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false SCUBA diving. 197.430 Section 197.430 Shipping COAST... GENERAL PROVISIONS Commercial Diving Operations Specific Diving Mode Procedures § 197.430 SCUBA diving. The diving supervisor shall insure that— (a) SCUBA diving is not conducted— (1) Outside the...

  9. Predicting performance in competitive apnea diving. Part III: deep diving.

    PubMed

    Schagatay, Erika

    2011-12-01

    The first of these reviews described the physiological factors defining the limits of static apnea, while the second examined performance in apneic distance swimming. This paper reviews the factors determining performance in depth disciplines, where hydrostatic pressure is added to the stressors associated with apnea duration and physical work. Apneic duration is essential for performance in all disciplines, and is prolonged by any means that increases gas storage or tolerance to asphyxia or reduces metabolic rate. For underwater distance swimming, the main challenge is to restrict metabolism despite the work of swimming, and to redirect blood flow to allow the most vital functions. Here, work economy, local tissue energy and oxygen stores, anaerobic capacity of the muscles, and possibly technical improvements will be essential for further development. In the depth disciplines, direct pressure effects causing barotrauma, the narcotic effects of gases, decompression sickness (DCS) and possibly air embolism during ascent need to be taken into account, as does the risk of hypoxia when the dive cannot be rapidly interrupted before the surface is reached again. While in most deep divers apneic duration is not the main limitation thus far, greater depths may call for exceptionally long apneas and slower ascents to avoid DCS. Narcotic effects may also affect the ultimate depth limit, which the divers currently performing 'constant weight with fins' dives predict to be around 156 metres' sea water. To reach these depths, serious physiological challenges have to be met, technical developments needed and safety procedures developed concomitantly. PMID:22183699

  10. Myocardial Po2 does not limit aerobic metabolism in the postischemic heart.

    PubMed

    Chung, Youngran

    2016-01-15

    Reperfused hypertrophic hearts are prone to develop reflow abnormalities, which are likely to impair O2 return to the myocardium. Yet, reflow deficit may not be the only factor determining postischemic oxygenation in the hypertrophic heart. Altered O2 demand may also contribute to hypoxia. In addition, the extent to which myocardial Po2 dictates energy and functional recovery in the reperfused heart remains uncertain. In the present study, moderately hypertrophied hearts from spontaneously hypertensive rats were subjected to ischemia-reperfusion, and the recovery time courses of pH and high-energy phosphates were followed by (31)P NMR. (1)H NMR measurement of intracellular myoglobin assessed tissue O2 levels. The present study found that the exacerbation of hypoxia in the postischemic spontaneously hypertensive rat heart arises mostly from impaired microvascular supply of O2. However, postischemic myocardial Po2, at least when it exceeds ∼18% of the preischemic level, does not limit mitochondrial respiration and high-energy phosphate resynthesis. It only passively reflects changes in the O2 supply-demand balance. PMID:26589325

  11. Physiological and clinical aspects of apnea diving.

    PubMed

    Muth, Claus-Martin; Ehrmann, Ulrich; Radermacher, Peter

    2005-09-01

    Apnea diving is a fascinating example of applied physiology. The record for apnea diving as an extreme sport is 171 meters, 8:58 minutes. The short time beneath the surface induces profound cardiovascular and respiratory effects. Variations of blood-gas tensions result from the interaction of metabolism and the rapid sequence of compression and decompression. Decompression sickness is possible. Apnea divers can reach depths beyond the theoretic physiologic limit by using the lung-packing maneuver. Apnea divers exhibit a fall in heart rate, which can be trained and is an oxygen-conserving effect, but increases the incidence of ventricular arrhythmia. PMID:16140133

  12. The Physics of Diving

    NASA Astrophysics Data System (ADS)

    Katzgraber, Helmut

    2007-10-01

    The underwater world, and in particular our oceans, represent a final frontier of exploration. In the past, studying the underwater fauna and flora used to be a dangerous undertaking reserved to professional divers. Technological advances over the last 50 years have given sports divers the opportunity to explore this fascinating world using self-contained underwater breathing apparatuses (SCUBA). Despite these technological advances humans have to cope with an unusual environment: perception is different underwater and there is always a risk of decompression illness due to the ambient pressure. After a brief overview of SCUBA diving, some physical phenomena particular to diving will be presented.

  13. Can asthmatic subjects dive?

    PubMed

    Adir, Yochai; Bove, Alfred A

    2016-06-01

    Recreational diving with self-contained underwater breathing apparatus (scuba) has grown in popularity. Asthma is a common disease with a similar prevalence in divers as in the general population. Due to theoretical concern about an increased risk for pulmonary barotrauma and decompression sickness in asthmatic divers, in the past the approach to asthmatic diver candidates was very conservative, with scuba disallowed. However, experience in the field and data in the current literature do not support this dogmatic approach. In this review the theoretical risk factors of diving with asthma, the epidemiological data and the recommended approach to the asthmatic diver candidate will be described. PMID:27246598

  14. Diving in a warming world: the thermal sensitivity and plasticity of diving performance in juvenile estuarine crocodiles (Crocodylus porosus).

    PubMed

    Rodgers, Essie M; Schwartz, Jonathon J; Franklin, Craig E

    2015-01-01

    Air-breathing, diving ectotherms are a crucial component of the biodiversity and functioning of aquatic ecosystems, but these organisms may be particularly vulnerable to the effects of climate change on submergence times. Ectothermic dive capacity is thermally sensitive, with dive durations significantly reduced by acute increases in water temperature; it is unclear whether diving performance can acclimate/acclimatize in response to long-term exposure to elevated water temperatures. We assessed the thermal sensitivity and plasticity of 'fright-dive' capacity in juvenile estuarine crocodiles (Crocodylus porosus; n = 11). Crocodiles were exposed to one of three long-term thermal treatments, designed to emulate water temperatures under differing climate change scenarios (i.e. current summer, 28°C; 'moderate' climate warming, 31.5°C; 'high' climate warming, 35°C). Dive trials were conducted in a temperature-controlled tank across a range of water temperatures. Dive durations were independent of thermal acclimation treatment, indicating a lack of thermal acclimation response. Acute increases in water temperature resulted in significantly shorter dive durations, with mean submergence times effectively halving with every 3.5°C increase in water temperature (Q 10 0.17, P < 0.001). Maximal dive performances, however, were found to be thermally insensitive across the temperature range of 28-35°C. These results suggest that C. porosus have a limited or non-existent capacity to thermally acclimate sustained 'fright-dive' performance. If the findings here are applicable to other air-breathing, diving ectotherms, the functional capacity of these organisms will probably be compromised under climate warming. PMID:27293738

  15. Diving and pregnancy: what do we really know?

    PubMed

    Conger, Jacqueline; Magann, Everett F

    2014-09-01

    Exercise during pregnancy has been advocated by many professional organizations to promote fetal heath and maternal well-being. Those same professional organizations do not recommend diving during pregnancy because of the potential adverse outcomes that have been observed in the animal model. In nonpregnant women, diving becomes problematic at depth as the ambient pressure increases and more gases become dissolved in the bloodstream. This can result in oxygen toxicity and nitrogen narcosis. Too rapid an ascent from depth can cause nitrogen emboli that can lodge in joints and tissue, resulting in decompression sickness, known as "the bends." The best animal model to study the effects of diving on pregnancy is the sheep model. Bubbling has been observed in both ewes and their fetuses, with bubbles more common in the ewes. Repeated decompressions done improperly can lead to fetal death. Information on pregnancy outcomes in humans is more limited, with inconsistent data on diving and birth defects, spontaneous abortions, and stillbirth. Even in the face of overall increased resistance in the maternal or fetal placental circulations, the total placental blood flow is usually maintained, preventing adverse outcomes. It appears that the safest choice during pregnancy is to avoid diving; however, if the woman dove when she did not know she was pregnant, there is usually a normal outcome. If a women insists on diving during pregnancy, she should go to a depth of only 60 ft, and duration of her dive should be half that recommended by Navy dive table times. PMID:25229824

  16. Neurological effects of deep diving.

    PubMed

    Grønning, Marit; Aarli, Johan A

    2011-05-15

    Deep diving is defined as diving to depths more than 50 m of seawater (msw), and is mainly used for occupational and military purposes. A deep dive is characterized by the compression phase, the bottom time and the decompression phase. Neurological and neurophysiologic effects are demonstrated in divers during the compression phase and the bottom time. Immediate and transient neurological effects after deep dives have been shown in some divers. However, the results from the epidemiological studies regarding long term neurological effects from deep diving are conflicting and still not conclusive. Prospective clinical studies with sufficient power and sensitivity are needed to solve this very important issue. PMID:21377169

  17. Dive into Scuba

    ERIC Educational Resources Information Center

    Coelho, Jeffrey; Fielitz, Lynn R.

    2006-01-01

    Scuba is a unique physical education activity that middle school and high school students can experience in physical education to provide them with the basic skills needed to enjoy the sport for many years to come. This article describes the basic scuba diving equipment, proper training and certification for instructors and students, facilities,…

  18. Human Simulated Diving Experiments.

    ERIC Educational Resources Information Center

    Bruce, David S.; Speck, Dexter F.

    1979-01-01

    This report details several simulated divinq experiments on the human. These are suitable for undergraduate or graduate laboratories in human or environmental physiology. The experiment demonstrates that a diving reflex is precipitated by both facial cooling and apnea. (Author/RE)

  19. Toppling Techniques in Diving

    ERIC Educational Resources Information Center

    Wilson, Barry D.

    1977-01-01

    This paper demonstrates that in a toppling dive (1) a 1:1 ratio exists between the rotational speed of the diver immediately before and after the take-off and (2) the take-off angle as defined by Page is approximately 50 percent. (Author)

  20. Diving into Oceans.

    ERIC Educational Resources Information Center

    Braus, Judy, Ed.

    1992-01-01

    Ranger Rick's NatureScope is a creative education series dedicated to inspiring in children an understanding and appreciation of the natural world while developing the skills they will need to make responsible decisions about the environment. The topic of this issue is "Diving Into Oceans." Contents are organized into the following sections: (1)…

  1. The silent witness: using dive computer records in diving fatality investigations.

    PubMed

    Sayer, Martin D J; Azzopardi, Elaine

    2014-09-01

    Downloaded data from diving computers can offer invaluable insights into diving incidents resulting in fatalities. Such data form an essential part of subsequent investigations or in legal actions related to the diving incident. It is often tempting to accept the information being displayed from a computer download without question. However, there is a large variability between the makes and models of dive computer in how the data are recorded, stored and re-displayed and caution must be employed in the interpretation of the evidence. In reporting on downloaded data, investigators should be fully aware of the limitations in the data retrieved. They should also know exactly how to interpret parameters such as: the accuracy of the dive profile; the effects of different mode settings; the precision of displayed water temperatures; the potential for misrepresenting breathing rates where there are data from integrated monitoring systems, and be able to challenge some forms of displayed information either through re-modelling based on the pressure/time profiles or by testing the computers in standardised conditions. PMID:25311326

  2. Treatment of diving emergencies.

    PubMed

    Moon, R E

    1999-04-01

    Recognition of condition attributable to the environmental changes experienced by divers will facilitate appropriate treatment. The diagnosis of these conditions rarely requires sophisticated imaging or electrophysiologic testing. Divers who have suspected DCI, in addition to general supportive measures, should be administered fluids and oxygen and transported to a recompression chamber. For diving-related conditions, on-line consultation is available from the Divers Alert Network, Durham, NC (919-684-8111). PMID:10331136

  3. Neurology and diving.

    PubMed

    Massey, E Wayne; Moon, Richard E

    2014-01-01

    Diving exposes a person to the combined effects of increased ambient pressure and immersion. The reduction in pressure when surfacing can precipitate decompression sickness (DCS), caused by bubble formation within tissues due to inert gas supersaturation. Arterial gas embolism (AGE) can also occur due to pulmonary barotrauma as a result of breath holding during ascent or gas trapping due to disease, causing lung hyperexpansion, rupture and direct entry of alveolar gas into the blood. Bubble disease due to either DCS or AGE is collectively known as decompression illness. Tissue and intravascular bubbles can induce a cascade of events resulting in CNS injury. Manifestations of decompression illness can vary in severity, from mild (paresthesias, joint pains, fatigue) to severe (vertigo, hearing loss, paraplegia, quadriplegia). Particularly as these conditions are uncommon, early recognition is essential to provide appropriate management, consisting of first aid oxygen, targeted fluid resuscitation and hyperbaric oxygen, which is the definitive treatment. Less common neurologic conditions that do not require hyperbaric oxygen include rupture of a labyrinthine window due to inadequate equalization of middle ear pressure during descent, which can precipitate vertigo and hearing loss. Sinus and middle ear overpressurization during ascent can compress the trigeminal and facial nerves respectively, causing temporary facial hypesthesia and lower motor neuron facial weakness. Some conditions preclude safe diving, such as seizure disorders, since a convulsion underwater is likely to be fatal. Preventive measures to reduce neurologic complications of diving include exclusion of individuals with specific medical conditions and safe diving procedures, particularly related to descent and ascent. PMID:24365363

  4. Estimation of the rate of oxygen consumption of the common eider duck (Somateria mollissima), with some measurements of heart rate during voluntary dives.

    PubMed

    Hawkins, P A; Butler, P J; Woakes, A J; Speakman, J R

    2000-09-01

    The relationship between heart rate (f(H)) and rate of oxygen consumption (V(O2)) was established for a marine diving bird, the common eider duck (Somateria mollissima), during steady-state swimming and running exercise. Both variables increased exponentially with speed during swimming and in a linear fashion during running. Eleven linear regressions of V(O2) (ml kg(-1 )min(-1)) on f(H) (beats min(-1)) were obtained: five by swimming and six by running the birds. The common regression was described by V(O2)=10.1 + 0.15f(H) (r(2)=0.46, N=272, P<0.0001). The accuracy of this relationship for predicting mean V(O2) was determined for a group of six birds by recording f(H) continuously over a 2-day period and comparing estimated V(O2) obtained using the common regression with (i) V(O2) estimated using the doubly labelled water technique (DLW) and (ii) V(O2) measured using respirometry. A two-pool model produced the most accurate estimated V(O2) using DLW. Because of individual variability within mean values of V(O2) estimated using both techniques, there was no significant difference between mean V(O2) estimated using f(H) or DLW and measured V(O2) values (P>0.2), although individual errors were substantially less when f(H) was used rather than DLW to estimate V(O2). Both techniques are, however, only suitable for estimating mean V(O2) for a group of animals, not for individuals. Heart rate and behaviour were monitored during a bout of 63 voluntary dives by one female bird in an indoor tank 1.7 m deep. Tachycardia occurred both in anticipation of and following each dive. Heart rate decreased before submersion but was above resting values for the whole of the dive cycle. Mean f(H) at mean dive duration was significantly greater than f(H) while swimming at maximum sustainable surface speeds. Heart rate was used to estimate mean V(O2) during the dive cycle and to predict aerobic dive limit (ADL) for shallow dives. PMID:10952881

  5. Muscle Energy Stores and Stroke Rates of Emperor Penguins: Implications for Muscle Metabolism and Dive Performance

    PubMed Central

    Williams, Cassondra L.; Sato, Katsufumi; Shiomi, Kozue; Ponganis, Paul J.

    2016-01-01

    In diving birds and mammals, bradycardia and peripheral vasoconstriction potentially isolate muscle from the circulation. During complete ischemia, ATP production is dependent on the size of the myoglobin oxygen (O2) store and the concentrations of phosphocreatine (PCr) and glycogen (Gly). Therefore, we measured PCr and Gly concentrations in the primary underwater locomotory muscle of emperor penguin and modeled the depletion of muscle O2 and those energy stores under conditions of complete ischemia and a previously determined muscle metabolic rate. We also analyzed stroke rate to assess muscle workload variation during dives and evaluate potential limitations on the model. Measured PCr and Gly concentrations, 20.8 and 54.6 mmol kg−1, respectively, were similar to published values for non-diving animals. The model demonstrated that PCr and Gly provide a large anaerobic energy store, even for dives longer than 20 min. Stroke rate varied throughout the dive profile indicating muscle workload was not constant during dives as was assumed in the model. The stroke rate during the first 30 seconds of dives increased with increased dive depth. In extremely long dives, lower overall stroke rates were observed. Although O2 consumption and energy store depletion may vary during dives, the model demonstrated that PCr and Gly, even at concentrations typical of terrestrial birds and mammals, are a significant anaerobic energy store and can play an important role in the emperor penguin’s ability to perform long dives. PMID:22418705

  6. Medical aspects of sport diving.

    PubMed

    Bove, A A

    1996-05-01

    Medical issues in sport diving include illnesses that are caused by diving, and medical disorders that compromise safety. Cerebral air embolism and decompression sickness of the brain and spinal cord can result from diving. Sport divers may manifest a spectrum of symptoms from air embolism, which can range from unconsciousness to minimal symptoms, which include fatigue, personality change, poor concentration, irritability, and changes in vision. The physician must search for these minor symptoms in divers who are suspected of pulmonary barotrauma. Medical disorders of concern in diving include diseases of the lungs, the heart, the brain, and the endocrine system, particularly diabetes. Other factors involved in diving safety are exercise capacity and training. Clinical practice standards usually prohibit diving by individuals who have a seizure disorder that requires continuous medication. In the United States, we will not approve diving for individuals who have insulin-dependent diabetes or severe asthma. Some divers can return to diving after myocardial infarction or bypass surgery if they demonstrate good exercise tolerance and no ischemia on a graded exercise test, which simulates the physical activity needed for safe diving. PMID:9148089

  7. Neurological consequences of scuba diving with chronic sinusitis.

    PubMed

    Parell, G J; Becker, G D

    2000-08-01

    Sinus barotrauma from scuba diving is relatively common, usually self-limiting, and often the result of transient nasal pathology. We describe serious neurological sequelae occurring in two scuba divers who had chronic sinusitis We suggest guidelines for evaluating and treating divers who have chronic sinusitis. Divers with nasal or sinus pathology should be aware of the potentially serious consequences associated with scuba diving even after endoscopic sinus surgery to correct this condition. PMID:10942141

  8. Diving in a warming world: the thermal sensitivity and plasticity of diving performance in juvenile estuarine crocodiles (Crocodylus porosus)

    PubMed Central

    Rodgers, Essie M.; Schwartz, Jonathon J.; Franklin, Craig E.

    2015-01-01

    Air-breathing, diving ectotherms are a crucial component of the biodiversity and functioning of aquatic ecosystems, but these organisms may be particularly vulnerable to the effects of climate change on submergence times. Ectothermic dive capacity is thermally sensitive, with dive durations significantly reduced by acute increases in water temperature; it is unclear whether diving performance can acclimate/acclimatize in response to long-term exposure to elevated water temperatures. We assessed the thermal sensitivity and plasticity of ‘fright-dive’ capacity in juvenile estuarine crocodiles (Crocodylus porosus; n = 11). Crocodiles were exposed to one of three long-term thermal treatments, designed to emulate water temperatures under differing climate change scenarios (i.e. current summer, 28°C; ‘moderate’ climate warming, 31.5°C; ‘high’ climate warming, 35°C). Dive trials were conducted in a temperature-controlled tank across a range of water temperatures. Dive durations were independent of thermal acclimation treatment, indicating a lack of thermal acclimation response. Acute increases in water temperature resulted in significantly shorter dive durations, with mean submergence times effectively halving with every 3.5°C increase in water temperature (Q10 0.17, P < 0.001). Maximal dive performances, however, were found to be thermally insensitive across the temperature range of 28–35°C. These results suggest that C. porosus have a limited or non-existent capacity to thermally acclimate sustained ‘fright-dive’ performance. If the findings here are applicable to other air-breathing, diving ectotherms, the functional capacity of these organisms will probably be compromised under climate warming. PMID:27293738

  9. Exercise at depth alters bradycardia and incidence of cardiac anomalies in deep-diving marine mammals.

    PubMed

    Williams, Terrie M; Fuiman, Lee A; Kendall, Traci; Berry, Patrick; Richter, Beau; Noren, Shawn R; Thometz, Nicole; Shattock, Michael J; Farrell, Edward; Stamper, Andy M; Davis, Randall W

    2015-01-01

    Unlike their terrestrial ancestors, marine mammals routinely confront extreme physiological and physical challenges while breath-holding and pursuing prey at depth. To determine how cetaceans and pinnipeds accomplish deep-sea chases, we deployed animal-borne instruments that recorded high-resolution electrocardiograms, behaviour and flipper accelerations of bottlenose dolphins (Tursiops truncatus) and Weddell seals (Leptonychotes weddellii) diving from the surface to >200 m. Here we report that both exercise and depth alter the bradycardia associated with the dive response, with the greatest impacts at depths inducing lung collapse. Unexpectedly, cardiac arrhythmias occurred in >73% of deep, aerobic dives, which we attribute to the interplay between sympathetic and parasympathetic drivers for exercise and diving, respectively. Such marked cardiac variability alters the common view of a stereotypic 'dive reflex' in diving mammals. It also suggests the persistence of ancestral terrestrial traits in cardiac function that may help explain the unique sensitivity of some deep-diving marine mammals to anthropogenic disturbances. PMID:25592286

  10. Nutritional Assessment During a 14-d Saturation Dive: the NASA Extreme Environment Mission Operation V Project

    NASA Technical Reports Server (NTRS)

    Smith, S. M.; Davis-Street, J. E.; Fesperman, J. V.; Smith, M. D.; Rice, B. L.; Zwart, S. R.

    2006-01-01

    Ground-based analogs of spaceflight are an important means of studying physiological and nutritional changes associated with space travel, particularly since exploration missions are anticipated, and flight research opportunities are limited. A clinical nutritional assessment of the NASA Extreme Environment Mission Operation V (NEEMO) crew (4 M, 2 F) was conducted before, during, and after the 14-d saturation dive. Blood and urine samples were collected before (D-12 and D-1), during (MD 7 and MD 12), and after (R + 0 and R + 7) the dive. The foods were typical of the spaceflight food system. A number of physiological changes were reported both during the dive and post dive that are also commonly observed during spaceflight. Serum hemoglobin and hematocrit were decreased (P less than 0.05) post dive. Serum ferritin and ceruloplasmin significantly increased during the dive, while transferring receptors tended to go down during the dive and were significantly decreased by the last day (R + 0). Along with significant hematological changes, there was also evidence for increased oxidative damage and stress during the dive. 8-hydroxydeoxyguanosine was elevated (P less than 0.05) during the dive, while glutathione peroxidase and superoxide disrnutase activities were decreased (P less than 0.05) during the dive. Serum C-reactive protein (CRP) concentration also tended to increase during the dive, suggesting the presence of a stress-induced inflammatory response, Decreased leptin during the dive (P less than 0.05) may also be related to the increased stress. Similar to what is observed during spaceflight, subjects had decreased energy intake and weight loss during the dive. Together, these similarities to spaceflight provide a model to further define the physiological effects of spaceflight and investigate potential countermeasures.

  11. Identifying foraging events in deep diving southern elephant seals, Mirounga leonina, using acceleration data loggers

    NASA Astrophysics Data System (ADS)

    Gallon, S.; Bailleul, F.; Charrassin, J.-B.; Guinet, C.; Bost, C.-A.; Handrich, Y.; Hindell, M.

    2013-04-01

    Southern elephant seals (Mirounga leonina) range widely throughout the Southern Ocean and are associated with important habitats (e.g., ice edges, shelf) where they accumulate energy to fuel their reproductive efforts on land. Knowledge of the fine scale foraging behaviour used to garner this energy, however, is limited. For the first time, acceleration loggers were deployed on three adult southern elephant seals during a translocation study at Kerguelen Island. The aims of the study were to (1) identify prey capture attempts using 2-D accelerometer tags deployed on the head of southern elephant seals, (2) compare the number of foraging dives identified by simple dive depth profiles and accelerometer profiles and (3) compare dive characteristics between prey encounter and non-prey encounter dives. The 2-D loggers recorded depth every second, surge and heave accelerations at 8 or 16 Hz and were carried for periods between 23 and 121 h. Rapid head movements were interpreted to be associated with prey encounter events. Acceleration data detected possible prey encounter events in 39-52% of dives whilst 67-80% of dives were classified as foraging dives when using dive depth profiles alone. Prey encounters occurred in successive dives during days and nights and lasted between tenths of a second and 7.6 min. Binomial linear mixed effect models showed that seals were diving significantly deeper and increased both descent rate and bottom duration when encountering prey. Dive duration, however, did not significantly increase during dives with prey encounters. These results are in accordance with optimal foraging theory, which predicts that deep divers should increase both their transit rates and the time spent at depth when a profitable prey patch is encountered. These findings indicate that this technique is promising as it more accurately detects possible prey encounter events compared with dive depth profiles alone and thus provides a better understanding of seal foraging

  12. 29 CFR 1910.424 - SCUBA diving.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 5 2010-07-01 2010-07-01 false SCUBA diving. 1910.424 Section 1910.424 Labor Regulations... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Commercial Diving Operations Specific Operations Procedures § 1910.424 SCUBA diving. (a) General. Employers engaged in SCUBA diving shall comply with the...

  13. 29 CFR 1910.424 - SCUBA diving.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 5 2011-07-01 2011-07-01 false SCUBA diving. 1910.424 Section 1910.424 Labor Regulations... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Commercial Diving Operations Specific Operations Procedures § 1910.424 SCUBA diving. (a) General. Employers engaged in SCUBA diving shall comply with the...

  14. 43 CFR 15.8 - Skin diving.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 1 2013-10-01 2013-10-01 false Skin diving. 15.8 Section 15.8 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE § 15.8 Skin diving. Diving with camera, or diving for observation and pleasure is permitted and encouraged within...

  15. 43 CFR 15.8 - Skin diving.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 1 2014-10-01 2014-10-01 false Skin diving. 15.8 Section 15.8 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE § 15.8 Skin diving. Diving with camera, or diving for observation and pleasure is permitted and encouraged within...

  16. 43 CFR 15.8 - Skin diving.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 1 2011-10-01 2011-10-01 false Skin diving. 15.8 Section 15.8 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE § 15.8 Skin diving. Diving with camera, or diving for observation and pleasure is permitted and encouraged within...

  17. 43 CFR 15.8 - Skin diving.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 1 2012-10-01 2011-10-01 true Skin diving. 15.8 Section 15.8 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE § 15.8 Skin diving. Diving with camera, or diving for observation and pleasure is permitted and encouraged within the Preserve....

  18. 43 CFR 15.8 - Skin diving.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Skin diving. 15.8 Section 15.8 Public Lands: Interior Office of the Secretary of the Interior KEY LARGO CORAL REEF PRESERVE § 15.8 Skin diving. Diving with camera, or diving for observation and pleasure is permitted and encouraged within...

  19. Visual Impairment does not Limit Training Effects in Development of Aerobic and Anaerobic Capacity in Tandem Cyclists

    PubMed Central

    Malwina, Kamelska Anna; Krzysztof, Mazurek; Piotr, Zmijewski

    2015-01-01

    The study aimed to investigate the differences in the effects of 7-month training on aerobic and anaerobic capacity in tandem cycling athletes with and without visual impairment. In this study, Polish elite (n=13) and sub-elite (n=13) visually impaired (VI) (n=13; 40.8 ±12.8 years) and properly sighted (PS) (n=13; 36.7 ±12.2 years) tandem-cycling athletes participated voluntarily in 7-month routine training. The following pre-/post-training measurements were conducted on separate days: maximal oxygen uptake (VO2max) was estimated with age correction using the Physical Working Capacity test on a bicycle ergometer according to the Astrand-Ryhming method. Maximal power output (Pmax) was evaluated using the Quebec test on a bicycle ergometer. At baseline, VO2max (47.8 ±14.1 vs 42.0 ±8.3 ml/kg/min, respectively) and Pmax (11.5 ±1.5 vs 11.5 ±1.0 W/kg) did not differ significantly between PS and VI cyclists. However, differences in aerobic capacity were considered as clinically significant. Two-way ANOVA revealed that after 7 month training, there were statistically significant increases in VO2max (p=0.003) and Pmax (p=0.009) among VI (VO2max, +9.1%; Pmax, +6.3%) and PS (VO2max, +9.1%; Pmax, +11.7%) cyclists, however, no time × visual impairment interaction effect was found (VO2max, p=0.467; Pmax, p=0.364). After training, VO2max (p=0.03), but not Pmax (p=0.13), was significantly greater in elite compared to sub-elite tandem cyclists. VI and PS tandem cyclists showed similar rates of improvement in VO2max and Pmax after 7-month training. VO2max was a significant determinant of success in tandem cycling. This is one of the first studies providing reference values for aerobic and anaerobic capacity in visually impaired cyclists. PMID:26834877

  20. Visual Impairment does not Limit Training Effects in Development of Aerobic and Anaerobic Capacity in Tandem Cyclists.

    PubMed

    Malwina, Kamelska Anna; Krzysztof, Mazurek; Piotr, Zmijewski

    2015-11-22

    The study aimed to investigate the differences in the effects of 7-month training on aerobic and anaerobic capacity in tandem cycling athletes with and without visual impairment. In this study, Polish elite (n=13) and sub-elite (n=13) visually impaired (VI) (n=13; 40.8 ±12.8 years) and properly sighted (PS) (n=13; 36.7 ±12.2 years) tandem-cycling athletes participated voluntarily in 7-month routine training. The following pre-/post-training measurements were conducted on separate days: maximal oxygen uptake (VO2max) was estimated with age correction using the Physical Working Capacity test on a bicycle ergometer according to the Astrand-Ryhming method. Maximal power output (Pmax) was evaluated using the Quebec test on a bicycle ergometer. At baseline, VO2max (47.8 ±14.1 vs 42.0 ±8.3 ml/kg/min, respectively) and Pmax (11.5 ±1.5 vs 11.5 ±1.0 W/kg) did not differ significantly between PS and VI cyclists. However, differences in aerobic capacity were considered as clinically significant. Two-way ANOVA revealed that after 7 month training, there were statistically significant increases in VO2max (p=0.003) and Pmax (p=0.009) among VI (VO2max, +9.1%; Pmax, +6.3%) and PS (VO2max, +9.1%; Pmax, +11.7%) cyclists, however, no time × visual impairment interaction effect was found (VO2max, p=0.467; Pmax, p=0.364). After training, VO2max (p=0.03), but not Pmax (p=0.13), was significantly greater in elite compared to sub-elite tandem cyclists. VI and PS tandem cyclists showed similar rates of improvement in VO2max and Pmax after 7-month training. VO2max was a significant determinant of success in tandem cycling. This is one of the first studies providing reference values for aerobic and anaerobic capacity in visually impaired cyclists. PMID:26834877

  1. Diving decompression models and bubble metrics: modern computer syntheses.

    PubMed

    Wienke, B R

    2009-04-01

    A quantitative summary of computer models in diving applications is presented, underscoring dual phase dynamics and quantifying metrics in tissue and blood. Algorithms covered include the multitissue, diffusion, split phase gradient, linear-exponential, asymmetric tissue, thermodynamic, varying permeability, reduced gradient bubble, tissue bubble diffusion, and linear-exponential phase models. Defining relationships are listed, and diver staging regimens are underscored. Implementations, diving sectors, and correlations are indicated for models with a history of widespread acceptance, utilization, and safe application across recreational, scientific, military, research, and technical communities. Presently, all models are incomplete, but many (included above) are useful, having resulted in diving tables, underwater meters, and dive planning software. Those herein employ varying degrees of calibration and data tuning. We discuss bubble metrics in tissue and blood as a backdrop against computer models. The past 15 years, or so, have witnessed changes and additions to diving protocols and table procedures, such as shorter nonstop time limits, slower ascent rates, shallow safety stops, ascending repetitive profiles, deep decompression stops, helium based breathing mixtures, permissible reverse profiles, multilevel techniques, both faster and slower controlling repetitive tissue halftimes, smaller critical tensions, longer flying-after-diving surface intervals, and others. Stimulated by Doppler and imaging technology, table and decompression meter development, theory, statistics, chamber and animal testing, or safer diving consensus, these modifications affect a gamut of activity, spanning bounce to decompression, single to multiday, and air to mixed gas diving. As it turns out, there is growing support for many protocols on operational, experimental, and theoretical grounds, with bubble models addressing many concerns on plausible bases, but with further testing or

  2. Lung collapse in the diving sea lion: hold the nitrogen and save the oxygen

    PubMed Central

    McDonald, Birgitte I.; Ponganis, Paul J.

    2012-01-01

    Lung collapse is considered the primary mechanism that limits nitrogen absorption and decreases the risk of decompression sickness in deep-diving marine mammals. Continuous arterial partial pressure of oxygen profiles in a free-diving female California sea lion (Zalophus californianus) revealed that (i) depth of lung collapse was near 225 m as evidenced by abrupt changes in during descent and ascent, (ii) depth of lung collapse was positively related to maximum dive depth, suggesting that the sea lion increased inhaled air volume in deeper dives and (iii) lung collapse at depth preserved a pulmonary oxygen reservoir that supplemented blood oxygen during ascent so that mean end-of-dive arterial was 74 ± 17 mmHg (greater than 85% haemoglobin saturation). Such information is critical to the understanding and the modelling of both nitrogen and oxygen transport in diving marine mammals. PMID:22993241

  3. Poor flight performance in deep-diving cormorants.

    PubMed

    Watanabe, Yuuki Y; Takahashi, Akinori; Sato, Katsufumi; Viviant, Morgane; Bost, Charles-André

    2011-02-01

    Aerial flight and breath-hold diving present conflicting morphological and physiological demands, and hence diving seabirds capable of flight are expected to face evolutionary trade-offs regarding locomotory performances. We tested whether Kerguelen shags Phalacrocorax verrucosus, which are remarkable divers, have poor flight capability using newly developed tags that recorded their flight air speed (the first direct measurement for wild birds) with propeller sensors, flight duration, GPS position and depth during foraging trips. Flight air speed (mean 12.7 m s(-1)) was close to the speed that minimizes power requirement, rather than energy expenditure per distance, when existing aerodynamic models were applied. Flights were short (mean 92 s), with a mean summed duration of only 24 min day(-1). Shags sometimes stayed at the sea surface without diving between flights, even on the way back to the colony, and surface durations increased with the preceding flight durations; these observations suggest that shags rested after flights. Our results indicate that their flight performance is physiologically limited, presumably compromised by their great diving capability (max. depth 94 m, duration 306 s) through their morphological adaptations for diving, including large body mass (enabling a large oxygen store), small flight muscles (to allow for large leg muscles for underwater propulsion) and short wings (to decrease air volume in the feathers and hence buoyancy). The compromise between flight and diving, as well as the local bathymetry, shape the three-dimensional foraging range (<26 km horizontally, <94 m vertically) in this bottom-feeding cormorant. PMID:21228200

  4. Medical Aspects of Scuba Diving

    PubMed Central

    Suke, Ralph

    1985-01-01

    Scuba divers may encounter dangerous levels of stress, due to increased ambient pressures and hostile environments. Divers therefore require a high level of mental and cardiorespiratory fitness. They must be informed of specific contraindications to diving. Family physicians with a basic knowledge of the medical aspects of scuba diving are in a very good position to examine and advise sports divers. Screening mainly involves an assessment of emotional stability and cardiorespiratory fitness, and an ear, nose and throat examination. Common problems suffered by scuba divers are discussed, as are temporary and permanent contraindications to diving. PMID:21274131

  5. Diving behavior and fishing performance: the case of lobster artisanal fishermen of the Yucatan coast, Mexico.

    PubMed

    Huchim-Lara, Oswaldo; Salas, Silvia; Chin, Walter; Montero, Jorge; Fraga, Julia

    2015-01-01

    An average of 209 cases of decompression sickness (DCS) have been reported every year among artisanal fishermen. divers of the Yucatan Peninsula, Mexico. DCS is a major problem among fishermen divers worldwide. This paper explores how diving behavior and fishing techniques among fishermen relate to the probability of experiencing DCS (Pdcs). Fieldwork was conducted in two communities during the 2012-2013 fishing season. Fishermen were classified into three groups (two per group) according to their fishing performance and followed during their journeys. Dive profiles were recorded using Sensus Ultra dive recorders (Reefet Inc.). Surveys were used to record fishing yields from cooperative and individual fishermen along with fishing techniques and dive behavior. 120 dives were recorded. Fishermen averaged three dives/day, with an average depth of 47 ± 2 feet of sea water (fsw) and an average total bottom time (TBT) of 95 ± 11 minutes. 24% of dives exceeded the 2008 U.S. Navy no-decompression limit. The average ascent rate was 20 fsw/minute, and 5% of those exceeded 40 fsw/minute. Inadequate decompression was observed in all fishermen. Fishermen are diving outside the safety limits of both military and recreational standards. Fishing techniques and dive behavior were important factors in Pdcs. Fishermen were reluctant to seek treatment, and symptoms were relieved with analgesics. PMID:26403014

  6. [Asthma and scuba diving: can asthmatic patients dive?].

    PubMed

    Sade, Kobi; Wiesel, Ory; Kivity, Shmuel; Levo, Yoram

    2007-04-01

    Self-contained underwater breathing apparatus (scuba) diving has grown in popularity, with millions of divers enjoying the sport worldwide. This activity presents unique physical and physiological challenges to the respiratory system, raising numerous concerns about individuals with asthma who choose to dive. Asthma had traditionally been a contraindication to recreational diving, although this caveat has been ignored by large numbers of such patients. Herein we review the currently available literature to provide evidence-based evaluation of the risks associated with diving that are posed to asthmatics. Although there is some indication that asthmatics may be at an increased risk of pulmonary barotrauma, the risk seems to be small. Thus, under the right circumstances, patients with asthma can safely participate in recreational diving without any apparent increased risk of an asthma-related event. Decisions on whether or not diving is hazardous must be made on an individual basis and be founded upon an informed decision shared by both patient and physician. PMID:17476937

  7. Neurologic complications of scuba diving.

    PubMed

    Newton, H B

    2001-06-01

    Recreational scuba diving has become a popular sport in the United States, with almost 9 million certified divers. When severe diving injury occurs, the nervous system is frequently involved. In dive-related barotrauma, compressed or expanding gas within the ears, sinuses and lungs causes various forms of neurologic injury. Otic barotrauma often induces pain, vertigo and hearing loss. In pulmonary barotrauma of ascent, lung damage can precipitate arterial gas embolism, causing blockage of cerebral blood vessels and alterations of consciousness, seizures and focal neurologic deficits. In patients with decompression sickness, the vestibular system, spinal cord and brain are affected by the formation of nitrogen bubbles. Common signs and symptoms include vertigo, thoracic myelopathy with leg weakness, confusion, headache and hemiparesis. Other diving-related neurologic complications include headache and oxygen toxicity. PMID:11417773

  8. Neurological complications of underwater diving.

    PubMed

    Rosińska, Justyna; Łukasik, Maria; Kozubski, Wojciech

    2015-01-01

    The diver's nervous system is extremely sensitive to high ambient pressure, which is the sum of atmospheric and hydrostatic pressure. Neurological complications associated with diving are a difficult diagnostic and therapeutic challenge. They occur in both commercial and recreational diving and are connected with increasing interest in the sport of diving. Hence it is very important to know the possible complications associated with this kind of sport. Complications of the nervous system may result from decompression sickness, pulmonary barotrauma associated with cerebral arterial air embolism (AGE), otic and sinus barotrauma, high pressure neurological syndrome (HPNS) and undesirable effect of gases used for breathing. The purpose of this review is to discuss the range of neurological symptoms that can occur during diving accidents and also the role of patent foramen ovale (PFO) and internal carotid artery (ICA) dissection in pathogenesis of stroke in divers. PMID:25666773

  9. Pulmonary dysanapsis and diving assessments.

    PubMed

    Ong, Lin Min; Bennett, Michael H; Thomas, Paul S

    2009-01-01

    Airway obstruction is a relative contraindication to diving. Dive candidates are assessed clinically, and lung function tests evaluate variables such as forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and the FEV1/FVC ratio. A small number of individuals have a normal FEV1, but a disproportionately large lung capacity, or pulmonary dysanapsis. These individuals have a decreased FEV1/FVC ratio, suggesting airway obstruction, which may affect their dive medical assessments. Three cases of pulmonary dysanapsis presented for fitness-to-dive assessment. Case 1, a 29-year-old male had an FEV1: 3.52 L (85% predicted), FVC: 5.31 L (108.5% predicted), giving a FEV1/FVC of 66%. Case 2, a 25-year-old male with an FEV1: 4.55 L (95% predicted), FVC: 7.0 L (121% predicted) and a FEV1/FVC of 66%. Albuterol produced an FEV1 increase of 11%, but his hypertonic saline challenge was negative. Case 3, a 61-year-old man had an FEV1: 3.49 L (126% predicted), FVC: 7.06 L (216% predicted), and a FEV1/FVC of 49%. This report highlights pulmonary dysanapsis which may be confused with obstructive airway disease and applicants deemed unfit to dive. While pulmonary dysanapsis may increase the risk of airway hyperresponsiveness, there is no evidence of an association with diving-related pulmonary barotrauma. PMID:20112528

  10. Control of ventilation in diving birds.

    PubMed

    Butler, Patrick J; Halsey, Lewis G

    2008-01-01

    Studies on diving ducks indicate that the carotid bodies affect dive duration when the birds are hypoxic before a dive but not when they are hypercapnic. When close to their critical concentrations (beyond which the ducks will not dive), both oxygen and carbon dioxide reduce dive duration but hypercapnia has a much larger influence than hypoxia on surface duration. Also, excessive removal of carbon dioxide before a dive may be as important a factor in preparing for that dive as the replacement of the oxygen used during the previous dive. This observation is compatible with a physiological model of the control of diving behaviour in the Weddell seal which emphasises the significance of the level of carbon dioxide in the blood perfusing the brain. PMID:18085287

  11. Free and forced diving in ducks: habituation of the initial dive response.

    PubMed

    Gabrielsen, G W

    1985-01-01

    Response habituation in pekin ducks was observed during a study of the early phase of the dive response. This is interpreted as the orienting response and strongly suggests higher CNS influence in the initial phase of the forced immersion heart rate response. Repeated forced dives (20-30 s) of restrained ducks were performed with 40 s recovery period between dives. During the first dives, the ducks' heart rates fell 69% (272 +/- 8 to 83 +/- 32 beats X min-1, means +/- SE) of pre-dive values. The extent of this bradycardia decreased progressively as the dives were repeated. After 60 dives, the heart rates dropped by only 29% (248 +/- 3 to 177 +/- 25 beats X min-1 for pre-dive value). Voluntary diving of the ducks, lasting 5-20 s, caused no diving bradycardia. They showed breathing tachycardia which caused a 25% increase in heart rates above diving level (160 +/- 5 to 200 +/- 12 beats X min-1). PMID:3969834

  12. [Diving accidents. Emergency treatment of serious diving accidents].

    PubMed

    Schröder, S; Lier, H; Wiese, S

    2004-11-01

    Decompression injuries are potentially life-threatening incidents mainly due to a rapid decline in ambient pressure. Decompression illness (DCI) results from the presence of gas bubbles in the blood and tissue. DCI may be classified as decompression sickness (DCS) generated from the liberation of gas bubbles following an oversaturation of tissues with inert gas and arterial gas embolism (AGE) mainly due to pulmonary barotrauma. People working under hyperbaric pressure, e.g. in a caisson for general construction under water, and scuba divers are exposed to certain risks. Diving accidents can be fatal and are often characterized by organ dysfunction, especially neurological deficits. They have become comparatively rare among professional divers and workers. However, since recreational scuba diving is gaining more and more popularity there is an increasing likelihood of severe diving accidents. Thus, emergency staff working close to areas with a high scuba diving activity, e.g. lakes or rivers, may be called more frequently to a scuba diving accident. The correct and professional emergency treatment on site, especially the immediate and continuous administration of normobaric oxygen, is decisive for the outcome of the accident victim. The definitive treatment includes rapid recompression with hyperbaric oxygen. The value of adjunctive medication, however, remains controversial. PMID:15565421

  13. Diurnal and seasonal variations in the duration and depth of the longest dives in southern elephant seals (Mirounga leonina): possible physiological and behavioural constraints.

    PubMed

    Bennett, K A; McConnell, B J; Fedak, M A

    2001-02-01

    This study seeks to understand how the physiological constraints of diving may change on a daily and seasonal basis. Dive data were obtained from southern elephant seals (Mirounga leonina) from South Georgia using satellite relay data loggers. We analysed the longest (95th percentile) dive durations as proxies for physiological dive limits. A strong, significant relationship existed between the duration of these dives and the time of day and week of year in which they were performed. The depth of the deepest dives also showed a significant, but far less consistent, relationship with local time of day and season. Changes in the duration of the longest dives occurred irrespective of their depth. Dives were longest in the morning (04:00-12:00 h) and shortest in the evening (16:00-00:00 h). The size of the fluctuation varied among animals from 4.0 to 20.0 min. The daily pattern in dive depth was phase-shifted in relation to the diurnal rhythm in dive duration. Dives were deeper at midday and shallower around midnight. Greater daily changes in duration occurred in seals feeding in the open ocean than in those foraging on the continental shelf. The seasonal peak in the duration of the longest dives coincided with austral midwinter. The size of the increase in dive duration from autumn/spring to winter ranged from 11.5 to 30.0 min. Changes in depth of the longest dives were not consistently associated with particular times of year. The substantial diurnal and seasonal fluctuations in maximum dive duration may be a result of changes in the physiological capacity to remain submerged, in addition to temporal changes in the ecological constraints on dive behaviour. We speculate about the role of melatonin as a hormonal mediator of diving capability. PMID:11171347

  14. 46 CFR 197.432 - Surface-supplied air diving.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Surface-supplied air diving. 197.432 Section 197.432... STANDARDS GENERAL PROVISIONS Commercial Diving Operations Specific Diving Mode Procedures § 197.432 Surface-supplied air diving. The diving supervisor shall insure that— (a) Surface-supplied air diving is...

  15. 46 CFR 197.432 - Surface-supplied air diving.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Surface-supplied air diving. 197.432 Section 197.432... STANDARDS GENERAL PROVISIONS Commercial Diving Operations Specific Diving Mode Procedures § 197.432 Surface-supplied air diving. The diving supervisor shall insure that— (a) Surface-supplied air diving is...

  16. Diving seabirds: the stability of a diving elastic beam

    NASA Astrophysics Data System (ADS)

    Chang, Brian; Croson, Matthew; Jung, Sunghwan

    2015-11-01

    In this study, we examine the buckling stability of a beam attached to a cone plunge diving into a bath of water, which is inspired by diving birds. This beam-cone system initially experiences an impact force before the cone is completely submerged, followed by a hydrodynamic drag force. Using high speed imaging techniques, it was observed that the soft elastic beam exhibits either buckling (unstable) or non-buckling (stable) behaviors upon impact and submergence. Large cone angles, long beams, and high impact velocities likely cause buckling in the beam. By varying geometric factors of the beam-cone system and changing the impact velocity, a transition from non-buckling to buckling is characterized through physical experiments and is verified by an analytical model. This study elucidates under which conditions diving birds may possibly get injured.

  17. Why are chlorinated pollutants so difficult to degrade aerobically? Redox stress limits 1,3-dichloprop-1-ene metabolism by Pseudomonas pavonaceae

    PubMed Central

    Nikel, Pablo I.; Pérez-Pantoja, Danilo; de Lorenzo, Víctor

    2013-01-01

    Chlorinated pollutants are hardly biodegradable under oxic conditions, but they can often be metabolized by anaerobic bacteria through organohalide respiration reactions. In an attempt to identify bottlenecks limiting aerobic catabolism of 1,3-dichloroprop-1-ene (1,3-DCP; a widely used organohalide) in Pseudomonas pavonaceae, the possible physiological restrictions for this process were surveyed. Flow cytometry and a bioluminescence reporter of metabolic state revealed that cells treated with 1,3-DCP experienced an intense stress that could be traced to the endogenous production of reactive oxygen species (ROS) during the metabolism of the compound. Cells exposed to 1,3-DCP also manifested increased levels of d-glucose-6-P 1-dehydrogenase activity (G6PDH, an enzyme key to the synthesis of reduced NADPH), observed under both glycolytic and gluconeogenic growth regimes. The increase in G6PDH activity, as well as cellular hydroperoxide levels, correlated with the generation of ROS. Additionally, the high G6PDH activity was paralleled by the accumulation of d-glucose-6-P, suggesting a metabolic flux shift that favours the production of NADPH. Thus, G6PDH and its cognate substrate seem to play an important role in P. pavonaceae under redox stress caused by 1,3-DCP, probably by increasing the rate of NADPH turnover. The data suggest that oxidative stress associated with the biodegradation of 1,3-DCP reflects a significant barrier for the evolution of aerobic pathways for chlorinated compounds, thereby allowing for the emergence of anaerobic counterparts. PMID:23479756

  18. Diving behaviour and decompression sickness among Galapagos underwater harvesters.

    PubMed

    Westin, A A; Asvall, J; Idrovo, G; Denoble, P; Brubakk, A O

    2005-01-01

    Diving conditions, dive profiles, vascular bubbles, and symptoms of decompression sickness (DCS) in a group of Galapagos commercial divers are described. They harvest sea cucumbers from small boats with surface supplied air (hookah). Dive profiles for 12 divers were recorded using dive loggers, and bubble formation was measured in the pulmonary artery. DCS symptoms were assessed by interview. A total of 380 immersions were recorded over a nine day period. The divers did on average 6.3 immersions per day, in a yo-yo pattern. Mean overall depth was 34.5 FSW. Maximum recorded depth was 107 FSW. Average bottom time per day per diver was 175 minutes. 82 % of all ascents exceeded the recommended maximum ascent rate of 30 FSW/ min. High bubble grades were observed on six occasions, but the test was unreliable. Muscle and joint pain was reported on five occasions, in three different divers. Symptoms were typically managed by analgesics, in-water recompression or not at all. The divers were extremely reluctant to seek professional help for DCS symptoms, mostly due to the high costs of treatment. We conclude that the fishermen dive beyond standard no-decompression limits, and that DCS symptoms are common. PMID:16119309

  19. 29 CFR 1926.1084 - SCUBA diving.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false SCUBA diving. 1926.1084 Section 1926.1084 Labor Regulations...) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving Specific Operations Procedures § 1926.1084 SCUBA diving. Note: The requirements applicable to construction work under this section are identical to...

  20. 29 CFR 1926.1084 - SCUBA diving.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 8 2011-07-01 2011-07-01 false SCUBA diving. 1926.1084 Section 1926.1084 Labor Regulations...) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving Specific Operations Procedures § 1926.1084 SCUBA diving. Note: The requirements applicable to construction work under this section are identical to...

  1. 33 CFR 146.40 - Diving casualties.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... CONTINENTAL SHELF ACTIVITIES OPERATIONS OCS Facilities § 146.40 Diving casualties. Diving related casualties are reported in accordance with 46 CFR 197.484 and 197.486. ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Diving casualties. 146.40...

  2. 33 CFR 146.40 - Diving casualties.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... CONTINENTAL SHELF ACTIVITIES OPERATIONS OCS Facilities § 146.40 Diving casualties. Diving related casualties are reported in accordance with 46 CFR 197.484 and 197.486. ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Diving casualties. 146.40...

  3. A review of asthma and scuba diving.

    PubMed

    Tetzlaff, Kay; Muth, Claus M; Waldhauser, Lisa K

    2002-10-01

    An increasing number of asthmatics participate in recreational scuba diving. This activity presents unique physical and physiological challenges to the respiratory system. This review addresses the susceptibility of divers with asthma to diving accidents, acute asthmatic attacks, and long-term exacerbation of their disease. Recommendations on fitness to dive with asthma and airway hyperresponsiveness are provided. PMID:12442945

  4. 33 CFR 146.40 - Diving casualties.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... CONTINENTAL SHELF ACTIVITIES OPERATIONS OCS Facilities § 146.40 Diving casualties. Diving related casualties are reported in accordance with 46 CFR 197.484 and 197.486. ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Diving casualties. 146.40...

  5. 33 CFR 146.40 - Diving casualties.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... CONTINENTAL SHELF ACTIVITIES OPERATIONS OCS Facilities § 146.40 Diving casualties. Diving related casualties are reported in accordance with 46 CFR 197.484 and 197.486. ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Diving casualties. 146.40...

  6. 33 CFR 146.40 - Diving casualties.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... CONTINENTAL SHELF ACTIVITIES OPERATIONS OCS Facilities § 146.40 Diving casualties. Diving related casualties are reported in accordance with 46 CFR 197.484 and 197.486. ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Diving casualties. 146.40...

  7. Basic medical implications of scuba diving.

    PubMed

    Crook, R A

    1977-12-01

    The rapid growth of scuba diving as a sport and the vast expansion of underwater exploration for energy has made it necessary for all physicians to become familiar with diving emergencies. The basic principles of scuba diving and related clinical implications are outlined to provide a more meaningful understanding of problems which may affect a diver. PMID:604521

  8. 29 CFR 1926.1084 - SCUBA diving.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 8 2014-07-01 2014-07-01 false SCUBA diving. 1926.1084 Section 1926.1084 Labor Regulations...) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving Specific Operations Procedures § 1926.1084 SCUBA diving. Note: The requirements applicable to construction work under this section are identical to...

  9. 29 CFR 1926.1084 - SCUBA diving.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 8 2012-07-01 2012-07-01 false SCUBA diving. 1926.1084 Section 1926.1084 Labor Regulations...) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving Specific Operations Procedures § 1926.1084 SCUBA diving. Note: The requirements applicable to construction work under this section are identical to...

  10. 29 CFR 1926.1084 - SCUBA diving.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 8 2013-07-01 2013-07-01 false SCUBA diving. 1926.1084 Section 1926.1084 Labor Regulations...) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving Specific Operations Procedures § 1926.1084 SCUBA diving. Note: The requirements applicable to construction work under this section are identical to...

  11. The influence of oxygen and carbon dioxide on diving behaviour of tufted ducks, Aythya fuligula.

    PubMed

    Halsey, Lewis; Reed, Jane Z; Woakes, Anthony; Butler, Patrick

    2003-01-01

    While optimal diving models focus on the diver's oxygen (O(2)) stores as the predominant factor influencing diving behaviour, many vertebrate species surface from a dive before these stores are exhausted and may commence another dive well after their O(2) stores have been resaturated. This study investigates the influence of hypoxia and also hypercapnia on the dive cycle of tufted ducks, Aythya fuligula, in terms of surface duration and dive duration. The birds were trained to surface into a respirometer box after each dive to a feeding tray so that rates of O(2) uptake (VO2) and carbon dioxide output (VCO2) at the surface could be measured. Although Vco2 initially lagged behind Vo2, both respiratory gas stores were close to full adjustment after the average surface duration, indicating that they probably had a similar degree of influence on surface duration. Chemoreceptors, which are known to influence diving behaviour, detect changes in O(2) and CO(2) partial pressures in the arterial blood. Thus, the need to restore blood gas levels appears to be a strong stimulus to continue ventilation. Mean surface duration coincided with peak instantaneous respiratory exchange ratio due to predive anticipatory hyperventilation causing hypocapnia. For comparison, the relationship between surface duration and O(2) uptake in reanalysed data for two grey seals indicated that one animal tended to dive well after fully restocking its O(2) stores, while the other dived at the point of full restocking. More CO(2) is exchanged than O(2) in tufted ducks during the last few breaths before the first dive of a bout, serving to reduce CO(2) stores and suggesting that hypercapnia rather than hypoxia is more often the limiting factor on asphyxia tolerance during dives. Indeed, according to calculations of O(2) stores and O(2) consumption rates over modal diving durations, a lack of O(2) does not seem to be associated with the termination of a dive in tufted ducks. However, factors other

  12. Scaling matters: incorporating body composition into Weddell seal seasonal oxygen store comparisons reveals maintenance of aerobic capacities.

    PubMed

    Shero, Michelle R; Costa, Daniel P; Burns, Jennifer M

    2015-10-01

    Adult Weddell seals (Leptonychotes weddellii) haul-out on the ice in October/November (austral spring) for the breeding season and reduce foraging activities for ~4 months until their molt in the austral fall (January/February). After these periods, animals are at their leanest and resume actively foraging for the austral winter. In mammals, decreased exercise and hypoxia exposure typically lead to decreased production of O2-carrying proteins and muscle wasting, while endurance training increases aerobic potential. To test whether similar effects were present in marine mammals, this study compared the physiology of 53 post-molt female Weddell seals in the austral fall to 47 pre-breeding females during the spring in McMurdo Sound, Antarctica. Once body mass and condition (lipid) were controlled for, there were no seasonal changes in total body oxygen (TBO2) stores. Within each season, hematocrit and hemoglobin values were negatively correlated with animal size, and larger animals had lower mass-specific TBO2 stores. But because larger seals had lower mass-specific metabolic rates, their calculated aerobic dive limit was similar to smaller seals. Indicators of muscular efficiency, myosin heavy chain composition, myoglobin concentrations, and aerobic enzyme activities (citrate synthase and β-hydroxyacyl CoA dehydrogenase) were likewise maintained across the year. The preservation of aerobic capacity is likely critical to foraging capabilities, so that following the molt Weddell seals can rapidly regain body mass at the start of winter foraging. In contrast, muscle lactate dehydrogenase activity, a marker of anaerobic metabolism, exhibited seasonal plasticity in this diving top predator and was lowest after the summer period of reduced activity. PMID:26164426

  13. Effects of diving and oxygen on autonomic nervous system and cerebral blood flow.

    PubMed

    Winklewski, Pawel J; Kot, Jacek; Frydrychowski, Andrzej F; Nuckowska, Magdalena K; Tkachenko, Yurii

    2013-09-01

    Recreational scuba diving is a popular leisure activity with the number of divers reaching several millions worldwide. Scuba diving represents a huge challenge for integrative physiology. In mammalian evolution, physiological reflexes developed to deal with lack of oxygen, rather than with an excess, which makes adaptations to scuba diving more difficult to describe and understand than those associated with breath-hold diving. The underwater environment significantly limits the use of equipment to register the organism's functions, so, in most instances, scientific theories are built on experiments that model real diving to some extent, like hyperbaric exposures, dive reflexes or water immersion. The aim of this review is to summarise the current knowledge related to the influence exerted by physiological conditions specific to diving on the autonomic nervous system and cerebral blood flow. The main factors regulating cerebral blood flow during scuba diving are discussed as follows: 1) increased oxygen partial pressure; 2) immersion-related trigemino-cardiac reflexes and 3) exposure to cold, exercise and stress. Also discussed are the potential mechanisms associated with immersion pulmonary oedema. PMID:24122190

  14. Recreational technical diving part 2: decompression from deep technical dives.

    PubMed

    Doolette, David J; Mitchell, Simon J

    2013-06-01

    Technical divers perform deep, mixed-gas 'bounce' dives, which are inherently inefficient because even a short duration at the target depth results in lengthy decompression. Technical divers use decompression schedules generated from modified versions of decompression algorithms originally developed for other types of diving. Many modifications ostensibly produce shorter and/or safer decompression, but have generally been driven by anecdote. Scientific evidence relevant to many of these modifications exists, but is often difficult to locate. This review assembles and examines scientific evidence relevant to technical diving decompression practice. There is a widespread belief that bubble algorithms, which redistribute decompression in favour of deeper decompression stops, are more efficient than traditional, shallow-stop, gas-content algorithms, but recent laboratory data support the opposite view. It seems unlikely that switches from helium- to nitrogen-based breathing gases during ascent will accelerate decompression from typical technical bounce dives. However, there is evidence for a higher prevalence of neurological decompression sickness (DCS) after dives conducted breathing only helium-oxygen than those with nitrogen-oxygen. There is also weak evidence suggesting less neurological DCS occurs if helium-oxygen breathing gas is switched to air during decompression than if no switch is made. On the other hand, helium-to-nitrogen breathing gas switches are implicated in the development of inner-ear DCS arising during decompression. Inner-ear DCS is difficult to predict, but strategies to minimize the risk include adequate initial decompression, delaying helium-to-nitrogen switches until relatively shallow, and the use of the maximum safe fraction of inspired oxygen during decompression. PMID:23813463

  15. Diving and marine medicine review part II: diving diseases.

    PubMed

    Spira, A

    1999-09-01

    Diving is a high-risk sport. There are approximately between 1 to 3 million recreational scuba divers in the USA (with over a quarter-million learning scuba annually); there are about 1 million in Europe and over 50,000 in the United Kingdom. In this population 3-9 deaths/100,000 occur annually in the US alone, and those surviving diving injuries far exceeds this. Diving morbidity can be from near-drowning, from gas bubbles, from barotrauma or from environmental hazards. In reality, the most common cause of death in divers is drowning (60%), followed by pulmonary-related illnesses. The mean number of annual diving fatalities in the USA from 1970 to 1993 was 103.5 (sd 24.0) and the median was 106. This article will focus primarily upon pressure effects on the health of a diver. There are two principle ways pressure can affect us: by direct mechanical effects and by changing the partial pressures of inspired gases. Dysbarism is a general term used to describe pathology from altered environmental pressure, and has two main forms: barotrauma from the uncontrolled expansion of gas within gas-filled body compartments and decompression sickness from too rapid a return to atmospheric pressure after breathing air under increased pressures. Greater than 90% of the human body is either water or bone, which is incompressible; the areas directly affected by pressure changes thus are those that are filled with air or gas. These sites include the middle ear, the eustachian tube, the sinuses, the thorax, and the gastrointestinal tract. Air in these cavities is compressed when the ambient pressure rises because the pressure of inhaled air must equilibrate with the ambient pressure. PMID:10467155

  16. DIVE Into Metadata With MMI

    NASA Astrophysics Data System (ADS)

    Neiswender, C.; Bermudez, L.; Galbraith, N. R.; Graybeal, J.

    2007-12-01

    Within research environments, good, usable data is paramount to scientific success. However, extremely diverse data is often distributed across many institutions, collected in a variety of ways, and stored in dissimilar systems. Standards-based interoperability is the key to harnessing this variety into a strategic set of usable data. As a community collaboration, the Marine Metadata Interoperability project (MMI) exists to promote the exchange, integration and use of marine data through enhanced data publishing, discovery, documentation and accessibility. To accomplish these goals, MMI has established a collaborative web environment (http://marinemetadata.org), informative guides, workshops on current topics, vocabulary working groups, and interoperable projects (OOSTethys and the OGC Oceans Interoperability Experiment, http://www.oostethys.org/). In January 2008, MMI will launch a new initiative: the DIVE Strike Force. Called DIVE for Discover, Interrogate, Validate and Educate. The MMI strike force initiative will facilitate concentrated research into a specific area needed by the marine science community. Each focused team of scientists, technologists and data managers will work to comprehensively review and explain existing capabilities and best practices, comparing existing solutions for the community. For this first DIVE Strike Force, team efforts will be focused on metadata tools. The Tools Strike Force will: * Discover available tools for the creation and publication of metadata and metadata vocabularies; * Interrogate the community about each tool, assessing criteria to be agreed upon, for example the capabilities of each, strengths and weaknesses, level of adoption, and where each tool would best be used; * Validate the best and most applicable tools objectively; * Educate the wider marine metadata community using the MMI webpage, and other resources as appropriate. Participants in each DIVE will be solicited from throughout the community, and

  17. 46 CFR 197.210 - Designation of diving supervisor.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Designation of diving supervisor. 197.210 Section 197... HEALTH STANDARDS GENERAL PROVISIONS Commercial Diving Operations General § 197.210 Designation of diving supervisor. The name of the diving supervisor for each commercial diving operation shall be— (a)...

  18. 46 CFR 197.210 - Designation of diving supervisor.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Designation of diving supervisor. 197.210 Section 197... HEALTH STANDARDS GENERAL PROVISIONS Commercial Diving Operations General § 197.210 Designation of diving supervisor. The name of the diving supervisor for each commercial diving operation shall be— (a)...

  19. 46 CFR 197.210 - Designation of diving supervisor.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Designation of diving supervisor. 197.210 Section 197... HEALTH STANDARDS GENERAL PROVISIONS Commercial Diving Operations General § 197.210 Designation of diving supervisor. The name of the diving supervisor for each commercial diving operation shall be— (a)...

  20. 46 CFR 197.210 - Designation of diving supervisor.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Designation of diving supervisor. 197.210 Section 197... HEALTH STANDARDS GENERAL PROVISIONS Commercial Diving Operations General § 197.210 Designation of diving supervisor. The name of the diving supervisor for each commercial diving operation shall be— (a)...

  1. 46 CFR 197.210 - Designation of diving supervisor.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Designation of diving supervisor. 197.210 Section 197... HEALTH STANDARDS GENERAL PROVISIONS Commercial Diving Operations General § 197.210 Designation of diving supervisor. The name of the diving supervisor for each commercial diving operation shall be— (a)...

  2. Buoyancy under Control: Underwater Locomotor Performance in a Deep Diving Seabird Suggests Respiratory Strategies for Reducing Foraging Effort

    PubMed Central

    Cook, Timothée R.; Kato, Akiko; Tanaka, Hideji; Ropert-Coudert, Yan; Bost, Charles-André

    2010-01-01

    Background Because they have air stored in many body compartments, diving seabirds are expected to exhibit efficient behavioural strategies for reducing costs related to buoyancy control. We study the underwater locomotor activity of a deep-diving species from the Cormorant family (Kerguelen shag) and report locomotor adjustments to the change of buoyancy with depth. Methodology/Principal Findings Using accelerometers, we show that during both the descent and ascent phases of dives, shags modelled their acceleration and stroking activity on the natural variation of buoyancy with depth. For example, during the descent phase, birds increased swim speed with depth. But in parallel, and with a decay constant similar to the one in the equation explaining the decrease of buoyancy with depth, they decreased foot-stroke frequency exponentially, a behaviour that enables birds to reduce oxygen consumption. During ascent, birds also reduced locomotor cost by ascending passively. We considered the depth at which they started gliding as a proxy to their depth of neutral buoyancy. This depth increased with maximum dive depth. As an explanation for this, we propose that shags adjust their buoyancy to depth by varying the amount of respiratory air they dive with. Conclusions/Significance Calculations based on known values of stored body oxygen volumes and on deep-diving metabolic rates in avian divers suggest that the variations of volume of respiratory oxygen associated with a respiration mediated buoyancy control only influence aerobic dive duration moderately. Therefore, we propose that an advantage in cormorants - as in other families of diving seabirds - of respiratory air volume adjustment upon diving could be related less to increasing time of submergence, through an increased volume of body oxygen stores, than to reducing the locomotor costs of buoyancy control. PMID:20352122

  3. [Characteristics of the human cardiovascular system in the human diving response].

    PubMed

    Baranova, T I

    2004-01-01

    Comparative-evolutional research of diving response showed that mechanisms of its expression had much in common in humans and in animals. Firstly, it involves a reflex bradycardia, vasoconstriction of peripheral vessels, and blood flow centralization. But, unlike animals whose diving response has some typical species peculiarities, human diving response is rather diverse. Four types of cardiovascular system response to face submersion were revealed: over-reactive, reactive, paradoxical, and nonreactive. These types were chosen according to the bradycardia character. It is also supposed that the occurrence of individual maximal R--R-interval, while serving as a signal to apnea stopping, is among the reasons of apnea activity limitation. PMID:15143489

  4. Investigation of Dive Brakes and a Dive-Recovery Flap on a High-Aspect-Ratio Wing in the Langley 8-Foot High-Speed Tunnel

    NASA Technical Reports Server (NTRS)

    Mattson, Axel T.

    1946-01-01

    The results of tests made to determine the aerodynamic characteristics of a solid brake, a slotted brake, and a dive-recovery flap mounted on a high aspect ratio wing at high Mach numbers are presented. The data were obtained in the Langley 8-foot high-speed tunnel for corrected Mach numbers up to 0.940. The results have been analyzed with regard to the suitability of dive-control devices for a proposed high-speed airplane in limiting the airplane terminal Mach number by the use of dive brakes and in achieving favorable dive-recovery characteristics by the use of a dive-recovery flap. The analysis of the results indicated that the slotted brake would limit the proposed airplane terminal Mach number to values below 0.880 for altitudes up to 35,000 feet and a wing loading of 80 pounds per square foot and the dive-recovery flap would produce trim changes required for controlled pull-outs at 25,000 feet for a Mach number range from 0.800 to 0.900. Basic changes in spanwise loading are presented to aid in the evaluation of the wing strength requirements.

  5. Oral and maxillofacial aspects of diving medicine.

    PubMed

    Brandt, Matthew T

    2004-02-01

    Sport diving has witnessed explosive growth in the past decade, as 8.5 million people are certified in the United States alone. Even though scuba diving is a relatively safe sport, there are serious risks that all divers must consider. Beyond the better-known sequelae such as decompression sickness, middle ear dysfunction, and potential central nervous system effects, scuba diving also carries inherent risk to the maxillofacial region. Atypical facial pain, temporomandibular joint dysfunction, sinus barotraumas, and barodontalgia have all been reported by dentists and physicians treating military, commercial, and sport divers. Additionally, clinicians must address anatomic concerns for would-be divers, including cleft lip and palate, edentulism, or patients with pre-existing temporomandibular dysfunction, midfacial trauma, or craniomaxillofacial surgery. Health care professionals should have a thorough understanding of the implications of scuba diving for consultation and recommendation regarding diving fitness and the treatment of adverse effects of scuba diving to the maxillofacial region. PMID:15040636

  6. Diving medicine: a review of current evidence.

    PubMed

    Lynch, James H; Bove, Alfred A

    2009-01-01

    Recreational scuba diving is a growing sport worldwide, with an estimated 4 million sport divers in the United States alone. Because divers may seek medical care for a disorder acquired in a remote location, physicians everywhere should be familiar with the physiology, injury patterns, and treatment of injuries and illnesses unique to the underwater environment. Failure to properly recognize, diagnose, and appropriately treat some diving injuries can have catastrophic results. In addition, recreational dive certification organizations require physical examinations for medical clearance to dive. This article will review both common and potentially life-threatening conditions associated with diving and will review current evidence behind fitness to dive considerations for elderly divers and those with common medical conditions. PMID:19587254

  7. Diving medicine: a review of current evidence.

    PubMed

    Lynch, James H; Bove, Alfred A

    2009-01-01

    Recreational scuba diving is a growing sport worldwide, with an estimated 4 million sport divers in the United States alone. Because divers may seek medical care for a disorder acquired in a remote location, physicians everywhere should be familiar with the physiology, injury patterns, and treatment of injuries and illnesses unique to the underwater environment. Failure to properly recognize, diagnose, and appropriately treat some diving injuries can have catastrophic results. In addition, recreational dive certification organizations require physical examinations for medical clearance to dive. This article will review both common and potentially life-threatening conditions associated with diving and will review current evidence behind fitness to dive considerations for elderly divers and those with common medical conditions. PMID:20112651

  8. Children’s Understanding of No Diving Warning Signs: Implications for Preventing Childhood Injury

    PubMed Central

    Morrongiello, Barbara A.; Cox, Amanda; Scott, Rachel; Sutey, Sarah E.

    2016-01-01

    The current study examined children’s understanding of No Diving warning signs. Normally-developing 7 to 10 year olds were asked questions to assess their understanding of text, images, and main messages on No Diving warning signs. These structured interviews were audio recorded and responses were later coded. Results revealed that children understood the behavior advised against (diving), why it is prohibited (can hit head on the bottom), and what can happen (serious injury including hospitalization). They understood that breaking your neck results in limitations in mobility and can occur from diving, but they did not anticipate that such an injury is likely to occur. There were no gender and few age differences, but diving experience was associated with children significantly downplaying their risk of injury. The findings suggest that having No Diving warning signs explicitly mention a broken neck, may serve to remind children of this potential consequence at the time of decision making. Active adult supervision is particularly important for children who have prior positive diving experiences. PMID:27399739

  9. Children's Understanding of No Diving Warning Signs: Implications for Preventing Childhood Injury.

    PubMed

    Morrongiello, Barbara A; Cox, Amanda; Scott, Rachel; Sutey, Sarah E

    2016-01-01

    The current study examined children's understanding of No Diving warning signs. Normally-developing 7 to 10 year olds were asked questions to assess their understanding of text, images, and main messages on No Diving warning signs. These structured interviews were audio recorded and responses were later coded. Results revealed that children understood the behavior advised against (diving), why it is prohibited (can hit head on the bottom), and what can happen (serious injury including hospitalization). They understood that breaking your neck results in limitations in mobility and can occur from diving, but they did not anticipate that such an injury is likely to occur. There were no gender and few age differences, but diving experience was associated with children significantly downplaying their risk of injury. The findings suggest that having No Diving warning signs explicitly mention a broken neck, may serve to remind children of this potential consequence at the time of decision making. Active adult supervision is particularly important for children who have prior positive diving experiences. PMID:27399739

  10. Shallow Water Diving - The NASA Experience

    NASA Technical Reports Server (NTRS)

    Fitzpatrick, Daniel; Kelsey-Seybold

    2010-01-01

    This slide presentation reviews some of the problems and solutions that personnel have experienced during sessions in the Neutral Bu0yancy Lab (NBL). It reviews the standard dive that occurs at the NBL, Boyles and Henry's laws as they relate to the effects of diving. It then reviews in depth some of the major adverse physiologic events that happen during a diving session: Ear and Sinus Barotrauma, Decompression Sickness, (DCS), Pulmonary Barotrauma (i.e., Arterial Gas Embolism (AGE). Mediastinal Emphysema, Subcutaneous Emphysema, and Pneumothorax) Oxygen Toxicity and Hypothermia. It includes information about the pulmonary function in NBL divers. Also included is recommendations about flying after diving.

  11. Persistent (patent) foramen ovale (PFO): implications for safe diving.

    PubMed

    Germonpré, Peter

    2015-06-01

    order to reduce the incidence of VGE. It has been convincingly shown that conservative dive profiles reduce DCI incidence even in divers with large PFOs, just as PFO closure does not protect completely from DCI if the dive profiles are aggressive. Prospective studies should not only focus on the reduction of DCI incidence after closure, but should take into account the costs and side effects of the procedure, as has been done in the cardiology and neurology studies. Imagine lung transplants becoming a routine operation, costly but with a high success rate; imagine also a longterm smoker suffering from a mild form of obstructive lung disease and exercise-limiting dyspnoea. Which of two options would you recommend: having a lung transplant and continue smoking as before, or quit smoking and observe a progressive improvement of pulmonary and cardiac pathology? As opposed to patients with thrombotic disease and migraine, divers can choose to reduce DCI risk. In fact, all it takes is acceptance that some types of diving carry too high a health risk - whether it is because of a PFO or another 'natural' factor. It would be unethical to promote PFO closure in divers solely on the basis of its efficacy of shunt reduction. Unfortunately, at least one device manufacturer has already done so in the past, citing various publications to specifically target recreational divers. Some technical diving organizations even have recommended preventive PFO closure in order to undertaking high-risk dive training. As scientists, we must not allow ourselves to be drawn into intuitive diver fears and beliefs. Nor should we let ourselves be blinded by the ease and seemingly low risk of the procedure. With proper and objective information provided by their diving medicine specialist, divers could make an informed decision, rather than focus on the simplistic idea that they need 'to get it fixed' in order to continue diving. A significant relationship between PFO and cerebral damage, in the absence

  12. Seasonal, Oceanographic and Atmospheric Drivers of Diving Behaviour in a Temperate Seal Species Living in the High Arctic

    PubMed Central

    Blanchet, Marie-Anne; Lydersen, Christian; Ims, Rolf A.; Kovacs, Kit M.

    2015-01-01

    The harbour seal (Phoca vitulina) population in Svalbard marks the northernmost limit of the species’ range. This small population experiences environmental extremes in sea and air temperatures, sea ice cover and also in light regime for this normally temperate species. This study deployed Conductivity Temperature Depth Satellite Relay Data Loggers (CTD-SRDLs) on 30 adult and juvenile harbour seals in 2009 and 2010 to study their foraging behaviour across multiple seasons. A total of 189,104 dives and 16,640 CTD casts (mean depth 72 m ± 59) were recorded. Individuals dove to a mean depth of 41 m ± 24 with a maximum dive depth range of 24 – 403 m. Dives lasted on average 204 sec ± 120 with maximum durations ranging between 240 – 2,220 sec. Average daily depth and duration of dives, number of dives, time spent diving and dive time/surface time were influenced by date, while sex, age, sea-ice concentration and their interactions were not particularly influential. Dives were deeper (~150 m), longer (~480 sec), less numerous (~250 dives/day) and more pelagic during the winter/early spring compared to the fall and animals spent proportionally less time at the bottom of their dives during the winter. Influxes of warm saline water, corresponding to Atlantic Water characteristics, were observed intermittently at depths ~100 m during both winters in this study. The seasonal changes in diving behaviour were linked to average weekly wind stresses from the north or north-east, which induced upwelling events onto the shelf through offshore Ekman transport. During these events the shelf became flooded with AW from the West Spitsbergen Current, which presumably brought Atlantic fish species close to shore and within the seals’ foraging depth-range. Predicted increased in the influx of AW in this region are likely going to favour the growth and geographic expansion of this harbour seal population in the future. PMID:26196289

  13. Seasonal, Oceanographic and Atmospheric Drivers of Diving Behaviour in a Temperate Seal Species Living in the High Arctic.

    PubMed

    Blanchet, Marie-Anne; Lydersen, Christian; Ims, Rolf A; Kovacs, Kit M

    2015-01-01

    The harbour seal (Phoca vitulina) population in Svalbard marks the northernmost limit of the species' range. This small population experiences environmental extremes in sea and air temperatures, sea ice cover and also in light regime for this normally temperate species. This study deployed Conductivity Temperature Depth Satellite Relay Data Loggers (CTD-SRDLs) on 30 adult and juvenile harbour seals in 2009 and 2010 to study their foraging behaviour across multiple seasons. A total of 189,104 dives and 16,640 CTD casts (mean depth 72 m ± 59) were recorded. Individuals dove to a mean depth of 41 m ± 24 with a maximum dive depth range of 24 - 403 m. Dives lasted on average 204 sec ± 120 with maximum durations ranging between 240 - 2,220 sec. Average daily depth and duration of dives, number of dives, time spent diving and dive time/surface time were influenced by date, while sex, age, sea-ice concentration and their interactions were not particularly influential. Dives were deeper (~150 m), longer (~480 sec), less numerous (~250 dives/day) and more pelagic during the winter/early spring compared to the fall and animals spent proportionally less time at the bottom of their dives during the winter. Influxes of warm saline water, corresponding to Atlantic Water characteristics, were observed intermittently at depths ~100 m during both winters in this study. The seasonal changes in diving behaviour were linked to average weekly wind stresses from the north or north-east, which induced upwelling events onto the shelf through offshore Ekman transport. During these events the shelf became flooded with AW from the West Spitsbergen Current, which presumably brought Atlantic fish species close to shore and within the seals' foraging depth-range. Predicted increased in the influx of AW in this region are likely going to favour the growth and geographic expansion of this harbour seal population in the future. PMID:26196289

  14. Rotation, Translation, and Trajectory in Diving

    ERIC Educational Resources Information Center

    Stroup, Francis; Bushnell, David L.

    1969-01-01

    The fundamental techniques of diving such as the approach, arm swing, hurdle, lift, body positions, and entrance form are relatively stable and can be reduced largely to habit. However, after a diver has mastered them, there remains the problem of partitioning the energy exerted in a dive between translation and rotation. (CK)

  15. The Physics of Breath-Hold Diving.

    ERIC Educational Resources Information Center

    Aguilella, Vicente; Aguilella-Arzo, Marcelo

    1996-01-01

    Analyzes physical features of breath-hold diving. Considers the diver's descent and the initial surface dive and presents examples that show the diver's buoyancy equilibrium varying with depth, the driving force supplied by finning, and the effect of friction between the water and the diver. (Author/JRH)

  16. Orbital fracture deterioration after scuba diving.

    PubMed

    Nakatani, Hiroko; Yoshioka, Nobutaka

    2009-07-01

    Sinus barotrauma is a common disease in divers. However, it is not familiar to maxillofacial surgeon. We presented orbital fracture deterioration by sinus barotrauma in scuba diving and a review of literatures. We also discussed the clinical features, the prevention, and the possible mechanism of orbital fracture deterioration after scuba diving. PMID:19625851

  17. Teaching Persons with Disabilities to SCUBA Diving.

    ERIC Educational Resources Information Center

    Jankowski, Louis W.

    This booklet is designed to sensitize and inform the scuba diving instructor on appropriate attitudes and successful methods for teaching scuba diving to persons with physical disability. It addresses misconceptions about people with disabilities and the importance of effective two-way communication and mutual respect between instructors and…

  18. Validation of diving decompression tables.

    PubMed

    Kłos, Ryszard; Nishi, Ron; Olszański, Roman

    2002-01-01

    Research on the validation of decompression tables is one of the common subject areas of the co-operation undertaken between the Defence and Civil Institute of Environmental Medicine, Toronto, Canada, and The Naval Academy of Gdynia, Poland. For several years now, a systematic survey of diving technologies has been conducted among the target projects financed by the Polish State Committee for Scientific Research and the Polish Navy. Among the most important problems discussed have been various aspects of decompression safety. The present paper shows a study to standardise and unify validation procedures for decompression in the Polish Navy. PMID:12608591

  19. Advanced deep sea diving equipment

    NASA Technical Reports Server (NTRS)

    Danesi, W. A.

    1972-01-01

    Design requirements are generated for a deep sea heavy duty diving system to equip salvage divers with equipment and tools that permit work of the same quality and in times approaching that done on the surface. The system consists of a helmet, a recirculator for removing carbon dioxide, and the diver's dress. The diver controls the inlet flow by the recirculatory control valve and is able to change closed cycle operation to open cycle if malfunction occurs. Proper function of the scrubber in the recirculator minimizes temperature and humidity effects as it filters the returning air.

  20. The cardiovascular system and diving risk.

    PubMed

    Bove, Alfred A

    2011-01-01

    Recreational scuba diving is a sport that requires a certain physical capacity, in addition to consideration of the environmental stresses produced by increased pressure, low temperature and inert gas kinetics in tissues of the body. Factors that may influence ability to dive safely include age, physical conditioning, tolerance of cold, ability to compensate for central fluid shifts induced by water immersion, and ability to manage exercise demands when heart disease might compromise exercise capacity. Patients with coronary heart disease, valvular heart disease, congenital heart disease and cardiac arrhythmias are capable of diving, but consideration must be given to the environmental factors that might interact with the cardiac disorder. Understanding of the interaction of the diving environment with various cardiac disorders is essential to providing a safe diving environment to individual divers with known heart disease. PMID:21877555

  1. [Medical aspects of diving in the tropics].

    PubMed

    Muth, C M; Müller, P; Kemmer, A

    2005-07-01

    Scuba diving vacations in tropical surroundings belong to the repertoire of most divers. In addition to carefully making travel plans and taking care of the necessary vaccinations and appropriate malaria prophylaxis, the following points also must be observed. The flight itself affects diving safety. In particular, a too short time interval between diving and the return flight can lead to decompression problems. Because most of the diving areas are reached by ship, many divers need a prophylaxis against motion sickness. Moreover, external otitis occurs more frequently while diving in the tropics. Finally, there is potential danger from the sea inhabitants, primarily from scorpion fishes, Portuguese Man-of-Wars, box jellyfishes as well as cone snails. PMID:16041936

  2. Cormorants dive through the Polar night.

    PubMed

    Grémillet, David; Kuntz, Grégoire; Gilbert, Caroline; Woakes, Antony J; Butler, Patrick J; le Maho, Yvon

    2005-12-22

    Most seabirds are visual hunters and are thus strongly affected by light levels. Dependence on vision should be problematic for species wintering at high latitudes, as they face very low light levels for extended periods during the Polar night. We examined the foraging rhythms of male great cormorants (Phalacrocorax carbo) wintering north of the Polar circle in West Greenland, conducting the first year-round recordings of the diving activity in a seabird wintering at high latitudes. Dive depth data revealed that birds dived every day during the Arctic winter and did not adjust their foraging rhythms to varying day length. Therefore, a significant proportion of the dive bouts were conducted in the dark (less than 1 lux) during the Polar night. Our study underlines the stunning adaptability of great cormorants and raises questions about the capacity of diving birds to use non-visual cues to target fish. PMID:17148235

  3. The death of buddy diving?

    PubMed

    Cooper, P David

    2011-12-01

    Dear Editor, By focussing on the details of the Watson case, I believe Bryan Walpole has missed the thrust of my earlier letter. I agree this was a complex case, which is why I deliberately avoided the murky specifics in order to consider the 'big-picture' ramifications of the judgement. My concerns relate to the potential consequences of the unintended interplay between unrelated developments in the medical and legal arenas. Taken together, I believe these developments threaten the very institution of buddy diving. I have been unable to verify Dr Walpole's claim that the statute under which Mr Watson was convicted has not been used previously in a criminal trial. I must, however, refute his assertion that this legislation is some sort of idiosyncratic historical hangover or legal curiosity unique to Queensland. Although the original legislation pre-dates Australian federation, this statute has survived intact through 110 years of reviews and amendments to the Queensland Criminal Code. The application of this 19th century law to the Watson case now provides a direct, post-federation, 21st century relevance. Nor is Queensland alone in having such a statute on its books. Section 151 of the Criminal Code Act in Dr Walpole's home state of Tasmania states "When a person undertakes to do any act, the omission to do which is or may be dangerous to human life or health, it is his duty to do that act." Similar statutes can also be found in the legislation of other Australian states and as far afield as New Zealand and Canada. The phrasing of the relevant sections is, in many cases, almost identical to Queensland's, reflecting the common judicial heritage of these places. Even if this ruling's reach extended no further than the Queensland border its ramifications would be immense. Tourism statistics reveal that over 1.2 million visitors perform nearly 3.5 million dives/snorkels in Queensland each year. An estimated 93% of international divers visiting Australia stopover in

  4. [Health aspects of diving in ENT medicine. Part II: Diving fitness].

    PubMed

    Klingmann, C; Wallner, F

    2004-09-01

    Diving has become increasingly popular. With the growing number of patients who want to dive, there is an increasing number of divers who require their regular medical examination. As ENT problems are the most common disorders in divers, otorhinolaryngologists regularly have to assess the diver's fitness. It should be noted that an ENT examination does not certify complete fitness to dive! Diving can be resumed 3 months after middle ear surgery, especially after tympanoplastic type I, II and III with insertion of a PORP, when there is regular middle ear ventilation without atrophic scars of the tympanic membrane. Even after stapes surgery, diving can be resumed when there are no signs of vestibular irritation during a provocation test. By 3 months after sinus surgery, the diver should perform a test dive under supervision before fitness to dive can be certified. After inner ear barotrauma, the diver remains fit to dive depending on his hearing ability in the involved ear. After inner ear decompression illness, one should look for a vascular right-to-left shunt before diving can be resumed. These and many more aspects are discussed in this article on how to determine whether a diver with ENT problems is fit to dive. PMID:15221086

  5. 29 CFR 1910.410 - Qualifications of dive team.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., DEPARTMENT OF LABOR OCCUPATIONAL SAFETY AND HEALTH STANDARDS Commercial Diving Operations Personnel... relevant to assigned tasks; (ii) Techniques of the assigned diving mode: and (iii) Diving operations and... control the exposure of others to hyperbaric conditions shall be trained in diving-related physics...

  6. 29 CFR 1910.410 - Qualifications of dive team.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., DEPARTMENT OF LABOR OCCUPATIONAL SAFETY AND HEALTH STANDARDS Commercial Diving Operations Personnel... relevant to assigned tasks; (ii) Techniques of the assigned diving mode: and (iii) Diving operations and... control the exposure of others to hyperbaric conditions shall be trained in diving-related physics...

  7. 46 CFR 197.320 - Diving ladder and stage.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Diving ladder and stage. 197.320 Section 197.320... STANDARDS GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.320 Diving ladder and stage. (a) Each diving ladder must— (1) Be capable of supporting the weight of at least two divers; (2) Extend...

  8. 29 CFR 1910.426 - Mixed-gas diving.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 5 2011-07-01 2011-07-01 false Mixed-gas diving. 1910.426 Section 1910.426 Labor... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Commercial Diving Operations Specific Operations Procedures § 1910.426 Mixed-gas diving. (a) General. Employers engaged in mixed-gas diving shall comply with the...

  9. 46 CFR 197.404 - Responsibilities of the diving supervisor.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Responsibilities of the diving supervisor. 197.404... SAFETY AND HEALTH STANDARDS GENERAL PROVISIONS Commercial Diving Operations Operations § 197.404 Responsibilities of the diving supervisor. (a) The diving supervisor shall— (1) Be fully cognizant of...

  10. 46 CFR 197.320 - Diving ladder and stage.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Diving ladder and stage. 197.320 Section 197.320... STANDARDS GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.320 Diving ladder and stage. (a) Each diving ladder must— (1) Be capable of supporting the weight of at least two divers; (2) Extend...

  11. 46 CFR 197.404 - Responsibilities of the diving supervisor.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Responsibilities of the diving supervisor. 197.404... SAFETY AND HEALTH STANDARDS GENERAL PROVISIONS Commercial Diving Operations Operations § 197.404 Responsibilities of the diving supervisor. (a) The diving supervisor shall— (1) Be fully cognizant of...

  12. 29 CFR 1910.426 - Mixed-gas diving.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 5 2010-07-01 2010-07-01 false Mixed-gas diving. 1910.426 Section 1910.426 Labor... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Commercial Diving Operations Specific Operations Procedures § 1910.426 Mixed-gas diving. (a) General. Employers engaged in mixed-gas diving shall comply with the...

  13. 46 CFR 197.432 - Surface-supplied air diving.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Surface-supplied air diving. 197.432 Section 197.432...-supplied air diving. The diving supervisor shall insure that— (a) Surface-supplied air diving is conducted... space; and (f) The surface-supplied air diver has the equipment required by § 197.346 (b) or (d)....

  14. 29 CFR 1910.425 - Surface-supplied air diving.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 5 2012-07-01 2012-07-01 false Surface-supplied air diving. 1910.425 Section 1910.425... Procedures § 1910.425 Surface-supplied air diving. (a) General. Employers engaged in surface-supplied air...-supplied air diving shall not be conducted at depths deeper than 190 fsw, except that dives with...

  15. 29 CFR 1910.425 - Surface-supplied air diving.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 5 2013-07-01 2013-07-01 false Surface-supplied air diving. 1910.425 Section 1910.425... Procedures § 1910.425 Surface-supplied air diving. (a) General. Employers engaged in surface-supplied air...-supplied air diving shall not be conducted at depths deeper than 190 fsw, except that dives with...

  16. 46 CFR 197.432 - Surface-supplied air diving.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Surface-supplied air diving. 197.432 Section 197.432...-supplied air diving. The diving supervisor shall insure that— (a) Surface-supplied air diving is conducted... space; and (f) The surface-supplied air diver has the equipment required by § 197.346 (b) or (d)....

  17. 46 CFR 197.404 - Responsibilities of the diving supervisor.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Responsibilities of the diving supervisor. 197.404... SAFETY AND HEALTH STANDARDS GENERAL PROVISIONS Commercial Diving Operations Operations § 197.404 Responsibilities of the diving supervisor. (a) The diving supervisor shall— (1) Be fully cognizant of...

  18. 29 CFR 1910.410 - Qualifications of dive team.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., DEPARTMENT OF LABOR OCCUPATIONAL SAFETY AND HEALTH STANDARDS Commercial Diving Operations Personnel... relevant to assigned tasks; (ii) Techniques of the assigned diving mode: and (iii) Diving operations and... control the exposure of others to hyperbaric conditions shall be trained in diving-related physics...

  19. 46 CFR 197.404 - Responsibilities of the diving supervisor.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Responsibilities of the diving supervisor. 197.404... SAFETY AND HEALTH STANDARDS GENERAL PROVISIONS Commercial Diving Operations Operations § 197.404 Responsibilities of the diving supervisor. (a) The diving supervisor shall— (1) Be fully cognizant of...

  20. 29 CFR 1910.410 - Qualifications of dive team.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., DEPARTMENT OF LABOR OCCUPATIONAL SAFETY AND HEALTH STANDARDS Commercial Diving Operations Personnel... relevant to assigned tasks; (ii) Techniques of the assigned diving mode: and (iii) Diving operations and... control the exposure of others to hyperbaric conditions shall be trained in diving-related physics...

  1. 29 CFR 1910.410 - Qualifications of dive team.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., DEPARTMENT OF LABOR OCCUPATIONAL SAFETY AND HEALTH STANDARDS Commercial Diving Operations Personnel... relevant to assigned tasks; (ii) Techniques of the assigned diving mode: and (iii) Diving operations and... control the exposure of others to hyperbaric conditions shall be trained in diving-related physics...

  2. 46 CFR 197.404 - Responsibilities of the diving supervisor.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Responsibilities of the diving supervisor. 197.404... SAFETY AND HEALTH STANDARDS GENERAL PROVISIONS Commercial Diving Operations Operations § 197.404 Responsibilities of the diving supervisor. (a) The diving supervisor shall— (1) Be fully cognizant of...

  3. Recreational scuba diving, patent foramen ovale and their associated risks.

    PubMed

    Schwerzmann, M; Seiler, C

    2001-06-30

    Scuba diving has become a popular leisure time activity with distinct risks to health owing to its physical characteristics. Knowledge of the behaviour of any mixture of breathable gases under increased ambient pressure is crucial for safe diving and gives clues as to the pathophysiology of compression or decompression related disorders. Immersion in cold water augments cardiac pre- and afterload due to an increase of intrathoracic blood volume and peripheral vasoconstriction. In very rare cases, the vasoconstrictor response can lead to pulmonary oedema. Immersion of the face in cold water is associated with bradycardia mediated by increased vagal tone. In icy water, the bradycardia can be so pronounced, that syncope results. For recreational dives, compressed air (i.e., 4 parts nitrogen and 1 part oxygen) is the preferred breathing gas. Its use is limited for diving to 40 to 50 m, otherwise nitrogen narcosis ("rapture of the deep") reduces a diver's cognitive function and increases the risk of inadequate reactions. At depths of 60 to 70 m oxygen toxicity impairs respiration and at higher partial pressures also functioning of the central nervous system. The use of special nitrogen-oxygen mixtures ("nitrox", 60% nitrogen and 40% oxygen as the typical example) decreases the probability of nitrogen narcosis and probably bubble formation, at the cost of increased risk of oxygen toxicity. Most of the health hazards during dives are consequences of changes in gas volume and formation of gas bubbles due to reduction of ambient pressure during a diver's ascent. The term barotrauma encompasses disorders related to over expansion of gas filled body cavities (mainly the lung and the inner ear). Decompression sickness results from the growth of gas nuclei in predominantly fatty tissue. Arterial gas embolism describes the penetration of such gas bubbles into the systemic circulation, either due to pulmonary barotrauma, transpulmonary passage after massive bubble formation

  4. Adrenal gland denervation and diving in ducks.

    PubMed

    Mangalam, H J; Jones, D R; Lacombe, A M

    1987-06-01

    The extreme elevation in plasma levels of free norepinephrine (NE) and free epinephrine (EP), which occurs during forced diving of ducks (Anas platyrhynchos), was studied before and after denervation of the adrenal glands. In intact animals both NE and EP concentration increased by up to two orders of magnitude in a 4-min dive but by a significantly lesser amount if the duck breathed O2 before the dive. Denervating the adrenal glands reduced the amounts of both catecholamines (CA) released during dives, plasma EP decreased to 10%, and NE to 50% of values obtained before denervation. Breathing O2 before a dive virtually eliminated CA release in denervates, indicating that hypoxia was the important non-neural releasing agent. Hypoxia was also the most important neural releasing agent compared with hypercapnia, acidosis, or hypoglycemia. Adrenal denervation did not cause significant changes in heart rate, blood pressure, arterial blood gas tensions, pH, or plasma glucose during dives, although denervation caused increased variation in some of these variables. In ducks CA release in dives is largely due to decreasing arterial O2 partial pressure, and full expression of the response is dependent on intact innervation of the adrenal gland. PMID:3591985

  5. [Fitness to dive in the otorhinolaryngological field].

    PubMed

    Klingmann, C; Praetorius, M; Böhm, F; Tetzlaff, K; Plinkert, P K

    2008-05-01

    In line with the rising number of recreational divers, the otorhinolaryngologist has to deal with growing numbers of diving-associated disorders of the ear, nose and throat (ENT). Nevertheless, the majority of divers present to their ENT doctor for assessment of their fitness to dive. On the basis of long-term follow-up examinations and increasing experience in diving medicine, even divers with a history of ENT problems can be considered fit to dive. Therefore, diving is possible after tympanoplasty, surgery to improve hearing including stapesplasty, after implantation of middle ear amplifiers or cochlear implants, after sinus or scull base surgery and even after canal wall down mastoidectomy, provided that certain requirements are fulfilled. Assessing fitness to dive after inner ear barotrauma as well as after inner ear decompression illness requires meticulous consideration of residual damage and possible underlying conditions like vascular right-to-left shunts. This article is based on the new recommendations of the German Undersea and Hyperbaric Medical Society for the assessment of fitness to dive in the otorhinolaryngological field. PMID:18415065

  6. Dive and discover: Expeditions to the seafloor

    NASA Astrophysics Data System (ADS)

    Ayers Lawrence, Lisa

    The Dive and Discover Web site is a virtual treasure chest of deep sea science and classroom resources. The goals of Dive and Discover are to engage students, teachers, and the general public in the excitement of ocean disco very through an interactive educational Web site. You can follow scientists on oceanographic research cruises by reading their daily cruise logs, viewing photos and video clips of the discoveries, and even e-mailing questions to the scientists and crew. WHOI has also included an "Educator's Companion" section with teaching strategies, activities, and assessments, making Dive and Discover an excellent resource for the classroom.

  7. Dive and discover: Expeditions to the seafloor

    NASA Astrophysics Data System (ADS)

    Lawrence, Lisa Ayers

    The Dive and Discover Web site is a virtual treasure chest of deep sea science and classroom resources. The goals of Dive and Discover are to engage students, teachers, and the general public in the excitement of ocean disco very through an interactive educational Web site. You can follow scientists on oceanographic research cruises by reading their daily cruise logs, viewing photos and video clips of the discoveries, and even e-mailing questions to the scientists and crew. WHOI has also included an “Educator's Companion” section with teaching strategies, activities, and assessments, making Dive and Discover an excellent resource for the classroom.

  8. A case of bilateral ophthalmoplegia while diving.

    PubMed

    Lee, Blair C; Young, Colin R

    2015-01-01

    This case report presents a military diver who became dysphoric and lost consciousness during a routine surface-supplied dive. The patient regained consciousness spontaneously, but the physical exam was notable for bilateral ophthalmoplegia. Full eye movement was regained during hyperbaric oxygen (HBO2) therapy, and the patient subsequently made a full recovery. Equipment and dive profile analysis led to the conclusion of hypercapnia and arterial gas embolism as the probable causes of the diver's symptoms. This is a unique case of isolated bilateral ophthalmoplegia presenting in a diving injury. PMID:26403021

  9. Dive Operator Use Patterns in the Designated No-Take Zones of the Florida Keys National Marine Sanctuary (FKNMS).

    PubMed

    Shivlani; Suman

    2000-06-01

    / The Florida Keys National Marine Sanctuary (FKNMS), created by Congress in 1990, addressed the issue of resource protection partly by proposing 26 "no-take" zones. These areas, discussed in the 1995 Draft Management Plan, disallowed all extractive activities, and four of the zones also prohibited diving and snorkeling. Furthermore, the Draft Management Plan considered recreational carrying capacity, proposing that use densities be studied and eventually limited in high-use and sensitive areas. Conducted with 62 commercial dive operators from the Florida Keys in 1995-96, this study uses geographic information systems (GIS) to determine the extent of FKNMS zone use by dive operators, assess the regional importance of FKNMS zones to operators, and compare management strategies by which to allow use while minimizing impacts to the coral reef resource. Dive operators took almost 70% of their total trips and 77% of their total divers to FKNMS zones in 1995. Although zone use is generally related to the proximity of dive locations, dive operators do rely disproportionately on single sites in certain regions. The resulting profiles demonstrate that management strategies need to consider disproportionate use, as well as the average number of users per trip, to effectively protect the region's environmental resources. In addition to implementing a carrying capacity plan, the FKNMS should consider a limited-entry system for dive operators. PMID:10790529

  10. Predicting performance in competitive apnoea diving. Part I: static apnoea.

    PubMed

    Schagatay, Erika

    2009-06-01

    Ever since the first deep diving competitions were organized, there has been debate about when the ultimate limits of human apnoeic performance will be reached, and which factors will determine these limits. Divers have thus far surpassed all former predictions by physiologists in depth and time. The common factor for all competitive apnoea disciplines is apnoeic duration, which can be prolonged by any means that increase total gas storage or tolerance to asphyxia, or reduce metabolic rate. These main factors can be broken down further into several physiological or psychophysiological factors, which are identified in this review. Like in other sports, the main aim in competitive apnoea is to extend human performance beyond the known limits. While a beginner may extend apnoeic duration by getting closer to his or her personal limit, the elite diver can only extend the duration further by pushing the individual physiological limit further by training. In order to achieve this, it is essential to identify the performance predicting factors of apnoea sports and which factors can be affected by training, work that has only just begun. This is the first of two papers reviewing the main factors predicting performance in competitive apnoea diving, which focuses on static apnoea, while the following paper will review dynamic distance and depth disciplines. Great improvements have been made in all diving disciplines in recent years and the 10-minute barrier in resting 'static apnoea' has been broached. Despite this, current training methods and the strategies employed suggest that duration can be prolonged still further, and divers themselves suggest the ultimate limit will be 15 minutes, which appears physiologically possible, for example, with further development of techniques to reduce metabolic rate. PMID:22753202

  11. Teaching Aerobic Fitness Concepts.

    ERIC Educational Resources Information Center

    Sander, Allan N.; Ratliffe, Tom

    2002-01-01

    Discusses how to teach aerobic fitness concepts to elementary students. Some of the K-2 activities include location, size, and purpose of the heart and lungs; the exercise pulse; respiration rate; and activities to measure aerobic endurance. Some of the 3-6 activities include: definition of aerobic endurance; heart disease risk factors;…

  12. P-47 Thunderbolt with dive recovery flaps

    NASA Technical Reports Server (NTRS)

    1946-01-01

    Caption: 'The dive recovery flaps on this P-47 Thunderbolt are barely visible underneath the wings. Photograph and caption published in Winds of Change, 75th Anniversary NASA publication (pages 52-53 and 130), by James Schultz.

  13. BacDive--the Bacterial Diversity Metadatabase.

    PubMed

    Söhngen, Carola; Bunk, Boyke; Podstawka, Adam; Gleim, Dorothea; Overmann, Jörg

    2014-01-01

    BacDive-the Bacterial Diversity Metadatabase (http://bacdive.dsmz.de) merges detailed strain-linked information on the different aspects of bacterial and archaeal biodiversity. Currently (release 9/2013), BacDive contains entries for 23 458 strains and provides information on their taxonomy, morphology, physiology, sampling and concomitant environmental conditions as well as molecular biology. Where available, links to access the respective biological resources are given. The majority of the BacDive data is manually annotated and curated. The BacDive portal offers an easy-to-use simple search and in addition powerful advanced search functionalities allowing to combine more than 30 search fields for text and numerical data. The user can compile individual sets of strains to a download selection that can easily be imported into nearly all spreadsheet applications. PMID:24214959

  14. Recreational Diving Impacts on Coral Reefs and the Adoption of Environmentally Responsible Practices within the SCUBA Diving Industry.

    PubMed

    Roche, Ronan C; Harvey, Chloe V; Harvey, James J; Kavanagh, Alan P; McDonald, Meaghan; Stein-Rostaing, Vivienne R; Turner, John R

    2016-07-01

    Recreational diving on coral reefs is an activity that has experienced rapidly growing levels of popularity and participation. Despite providing economic activity for many developing coastal communities, the potential role of dive impacts in contributing to coral reef damage is a concern at heavily dived locations. Management measures to address this issue increasingly include the introduction of programmes designed to encourage environmentally responsible practices within the dive industry. We examined diver behaviour at several important coral reef dive locations within the Philippines and assessed how diver characteristics and dive operator compliance with an environmentally responsible diving programme, known as the Green Fins approach, affected reef contacts. The role of dive supervision was assessed by recording dive guide interventions underwater, and how this was affected by dive group size. Of the 100 recreational divers followed, 88 % made contact with the reef at least once per dive, with a mean (±SE) contact rate of 0.12 ± 0.01 per min. We found evidence that the ability of dive guides to intervene and correct diver behaviour in the event of a reef contact decreases with larger diver group sizes. Divers from operators with high levels of compliance with the Green Fins programme exhibited significantly lower reef contact rates than those from dive operators with low levels of compliance. The successful implementation of environmentally responsible diving programmes, which focus on influencing dive industry operations, can contribute to the management of human impacts on coral reefs. PMID:27055531

  15. Recreational Diving Impacts on Coral Reefs and the Adoption of Environmentally Responsible Practices within the SCUBA Diving Industry

    NASA Astrophysics Data System (ADS)

    Roche, Ronan C.; Harvey, Chloe V.; Harvey, James J.; Kavanagh, Alan P.; McDonald, Meaghan; Stein-Rostaing, Vivienne R.; Turner, John R.

    2016-07-01

    Recreational diving on coral reefs is an activity that has experienced rapidly growing levels of popularity and participation. Despite providing economic activity for many developing coastal communities, the potential role of dive impacts in contributing to coral reef damage is a concern at heavily dived locations. Management measures to address this issue increasingly include the introduction of programmes designed to encourage environmentally responsible practices within the dive industry. We examined diver behaviour at several important coral reef dive locations within the Philippines and assessed how diver characteristics and dive operator compliance with an environmentally responsible diving programme, known as the Green Fins approach, affected reef contacts. The role of dive supervision was assessed by recording dive guide interventions underwater, and how this was affected by dive group size. Of the 100 recreational divers followed, 88 % made contact with the reef at least once per dive, with a mean (±SE) contact rate of 0.12 ± 0.01 per min. We found evidence that the ability of dive guides to intervene and correct diver behaviour in the event of a reef contact decreases with larger diver group sizes. Divers from operators with high levels of compliance with the Green Fins programme exhibited significantly lower reef contact rates than those from dive operators with low levels of compliance. The successful implementation of environmentally responsible diving programmes, which focus on influencing dive industry operations, can contribute to the management of human impacts on coral reefs.

  16. [Dynamics of parameters of energy metabolism at adaptation to diving in human].

    PubMed

    Baranova, T I; Kovalenko, R I; Mitrofanova, A V; Ianvareva, I N

    2010-01-01

    Studies of the diving reaction in the comparative-evolutionary aspect have shown that a complex of reactions providing the oxygen-saving effect during diving is inherent in human like in the secondary-aquatic mammals. This is confirmed by results of study of peculiarities of energy metabolism during imitation of diving (hold-up of respiration with immersion of face into the cold water--the cold-hypoxic-hypercapnic action) (CHHA). Data of gas analysis have shown that during the diving imitation the oxygen consumption rate is statistically significantly lower than during the usual hold-up of respiration (Genche's test). As shown by the study, this is due to the greater degree to vasoconstriction of peripheral vessels and selective redistribution of blood flow than to slowing down of the blood flow caused by reflex bradycardia during diving. It has been revealed that under effect of adaptation to CHHA, on the background of a decrease of the total energy consumption by the organism there occurs some increase of contribution of aerobic processes to its energy provision. Adaptation to CHHA has been shown to be accompanied by a decrease of reactivity of the parasympathetic chain of regulation of the heart chronotropic function and by an increase of duration of apnea. The duration of apnea is directly correlated with level of insulin--the hormone stimulating the anaerobic pathway of energy provision. Under effect of adaptation to CHHA there has been established an increase of the organism resistance to stress actions, which is confirmed by the lower levels of cortisol and thyroid hormones in representatives of the experimental group as compared with the control one. PMID:21061652

  17. Neurological long term consequences of deep diving.

    PubMed Central

    Todnem, K; Nyland, H; Skeidsvoll, H; Svihus, R; Rinck, P; Kambestad, B K; Riise, T; Aarli, J A

    1991-01-01

    Forty commercial saturation divers, mean age 34.9 (range 24-49) years, were examined one to seven years after their last deep dive (190-500 metres of seawater). Four had by then lost their divers' licence because of neurological problems. Twenty seven (68%) had been selected by neurological examination and electroencephalography before the deep dives. The control group consisted of 100 men, mean age 34.0 (range 22-48) years. The divers reported significantly more symptoms from the nervous system. Concentration difficulties and paraesthesia in feet and hands were common. They had more abnormal neurological findings by neurological examination compatible with dysfunction in the lumbar spinal cord or roots. They also had a larger proportion of abnormal electroencephalograms than the controls. The neurological symptoms and findings were highly significantly correlated with exposure to deep diving (depth included), but even more significantly correlated to air and saturation diving and prevalence of decompression sickness. Visual evoked potentials, brainstem auditory evoked potentials, and magnetic resonance imaging of the brain did not show more abnormal findings in the divers. Four (10%) divers had had episodes of cerebral dysfunction during or after the dives; two had had seizures, one had had transitory cerebral ischaemia and one had had transitory global amnesia. It is concluded that deep diving may have a long term effect on the nervous system of the divers. PMID:2025592

  18. SCUBA Diving and Asthma: Clinical Recommendations and Safety.

    PubMed

    Coop, Christopher A; Adams, Karla E; Webb, Charles N

    2016-02-01

    The objective of this article is to review the available studies regarding asthma and SCUBA (self-contained underwater breathing apparatus) diving. A literature search was conducted in MEDLINE to identify peer-reviewed articles related to asthma and SCUBA diving using the following keywords: asthma, allergy, and SCUBA diving. SCUBA diving is a popular sport with more than 9 million divers in the USA. SCUBA diving can be a dangerous sport. Bronchospasm can develop in asthmatic patients and cause airway obstruction. Airway obstruction may be localized to the distal airway which prevents gas elimination. Uncontrolled expansion of the distal airway may result in pulmonary barotrauma. There is also the risk of a gas embolism. Asthmatic divers can also aspirate seawater which may induce bronchospasm. Pollen contamination of their oxygen tank may exacerbate atopic asthma in patients. Diving may be hazardous to the lung function of patients with asthma. Despite the risks of SCUBA diving, many asthmatic individuals can dive without serious diving events. Diving evaluations for asthmatic patients have focused on a thorough patient history, spirometry, allergy testing, and bronchial challenges. For patients that wish to dive, their asthma should be well controlled without current chest symptoms. Patients should have a normal spirometry. Some diving societies recommend that an asthmatic patient should successfully pass a bronchial provocation challenge. Recommendations also state that exercise-, emotion-, and cold-induced asthmatics should not dive. Asthmatic patients requiring rescue medication within 48 h should not dive. PMID:25666876

  19. Can diving-induced tissue nitrogen supersaturation increase the chance of acoustically driven bubble growth in marine mammals?

    PubMed

    Houser, D S; Howard, R; Ridgway, S

    2001-11-21

    The potential for acoustically mediated causes of stranding in cetaceans (whales and dolphins) is of increasing concern given recent stranding events associated with anthropogenic acoustic activity. We examine a potentially debilitating non-auditory mechanism called rectified diffusion. Rectified diffusion causes gas bubble growth, which in an insonified animal may produce emboli, tissue separation and high, localized pressure in nervous tissue. Using the results of a dolphin dive study and a model of rectified diffusion for low-frequency exposure, we demonstrate that the diving behavior of cetaceans prior to an intense acoustic exposure may increase the chance of rectified diffusion. Specifically, deep diving and slow ascent/descent speed contributes to increased gas-tissue saturation, a condition that amplifies the likelihood of rectified diffusion. The depth of lung collapse limits nitrogen uptake per dive and the surface interval duration influences the amount of nitrogen washout from tissues between dives. Model results suggest that low-frequency rectified diffusion models need to be advanced, that the diving behavior of marine mammals of concern needs to be investigated to identify at-risk animals, and that more intensive studies of gas dynamics within diving marine mammals should be undertaken. PMID:11894990

  20. Training rats to voluntarily dive underwater: investigations of the mammalian diving response.

    PubMed

    McCulloch, Paul F

    2014-01-01

    Underwater submergence produces autonomic changes that are observed in virtually all diving animals. This reflexly-induced response consists of apnea, a parasympathetically-induced bradycardia and a sympathetically-induced alteration of vascular resistance that maintains blood flow to the heart, brain and exercising muscles. While many of the metabolic and cardiorespiratory aspects of the diving response have been studied in marine animals, investigations of the central integrative aspects of this brainstem reflex have been relatively lacking. Because the physiology and neuroanatomy of the rat are well characterized, the rat can be used to help ascertain the central pathways of the mammalian diving response. Detailed instructions are provided on how to train rats to swim and voluntarily dive underwater through a 5 m long Plexiglas maze. Considerations regarding tank design and procedure room requirements are also given. The behavioral training is conducted in such a way as to reduce the stressfulness that could otherwise be associated with forced underwater submergence, thus minimizing activation of central stress pathways. The training procedures are not technically difficult, but they can be time-consuming. Since behavioral training of animals can only provide a model to be used with other experimental techniques, examples of how voluntarily diving rats have been used in conjunction with other physiological and neuroanatomical research techniques, and how the basic training procedures may need to be modified to accommodate these techniques, are also provided. These experiments show that voluntarily diving rats exhibit the same cardiorespiratory changes typically seen in other diving animals. The ease with which rats can be trained to voluntarily dive underwater, and the already available data from rats collected in other neurophysiological studies, makes voluntarily diving rats a good behavioral model to be used in studies investigating the central aspects of the

  1. First Long-Term Behavioral Records from Cuvier’s Beaked Whales (Ziphius cavirostris) Reveal Record-Breaking Dives

    PubMed Central

    Schorr, Gregory S.; Falcone, Erin A.; Moretti, David J.; Andrews, Russel D.

    2014-01-01

    Cuvier’s beaked whales (Ziphius cavirostris) are known as extreme divers, though behavioral data from this difficult-to-study species have been limited. They are also the species most often stranded in association with Mid-Frequency Active (MFA) sonar use, a relationship that remains poorly understood. We used satellite-linked tags to record the diving behavior and locations of eight Ziphius off the Southern California coast for periods up to three months. The effort resulted in 3732 hr of dive data with associated regional movements – the first dataset of its kind for any beaked whale – and included dives to 2992 m depth and lasting 137.5 min, both new mammalian dive records. Deep dives had a group mean depth of 1401 m (s.d. = 137.8, n = 1142) and duration of 67.4 min (s.d. = 6.9). The group mean time between deep dives was 102.3 min (s.d. = 30.8, n = 783). While the previously described stereotypic pattern of deep and shallow dives was apparent, there was considerable inter- and intra-individual variability in most parameters. There was significant diel behavioral variation, including increased time near the surface and decreased shallow diving at night. However, maximum depth and the proportion of time spent on deep dives (presumed foraging), varied little from day to night. Surprisingly, tagged whales were present within an MFA sonar training range for 38% of days locations were received, and though comprehensive records of sonar use during tag deployments were not available, we discuss the effects frequent acoustic disturbance may have had on the observed behaviors. These data better characterize the true behavioral range of this species, and suggest caution should be exercised when drawing conclusions about behavior using short-term datasets. PMID:24670984

  2. First long-term behavioral records from Cuvier's beaked whales (Ziphius cavirostris) reveal record-breaking dives.

    PubMed

    Schorr, Gregory S; Falcone, Erin A; Moretti, David J; Andrews, Russel D

    2014-01-01

    Cuvier's beaked whales (Ziphius cavirostris) are known as extreme divers, though behavioral data from this difficult-to-study species have been limited. They are also the species most often stranded in association with Mid-Frequency Active (MFA) sonar use, a relationship that remains poorly understood. We used satellite-linked tags to record the diving behavior and locations of eight Ziphius off the Southern California coast for periods up to three months. The effort resulted in 3732 hr of dive data with associated regional movements--the first dataset of its kind for any beaked whale--and included dives to 2992 m depth and lasting 137.5 min, both new mammalian dive records. Deep dives had a group mean depth of 1401 m (s.d. = 137.8, n = 1142) and duration of 67.4 min (s.d. = 6.9). The group mean time between deep dives was 102.3 min (s.d. = 30.8, n = 783). While the previously described stereotypic pattern of deep and shallow dives was apparent, there was considerable inter- and intra-individual variability in most parameters. There was significant diel behavioral variation, including increased time near the surface and decreased shallow diving at night. However, maximum depth and the proportion of time spent on deep dives (presumed foraging), varied little from day to night. Surprisingly, tagged whales were present within an MFA sonar training range for 38% of days locations were received, and though comprehensive records of sonar use during tag deployments were not available, we discuss the effects frequent acoustic disturbance may have had on the observed behaviors. These data better characterize the true behavioral range of this species, and suggest caution should be exercised when drawing conclusions about behavior using short-term datasets. PMID:24670984

  3. Extremely deep recreational dives: the risk for carbon dioxide (CO(2)) retention and high pressure neurological syndrome (HPNS).

    PubMed

    Kot, Jacek

    2012-01-01

    Clear differences between professional and recreational deep diving are disappearing, at least when taking into account the types of breathing mixtures (oxygen, nitrox, heliox, and trimix) and range of dive parameters (depth and time). Training of recreational deep divers is conducted at depths of 120-150 metres and some divers dive to 180-200 metres using the same diving techniques. Extremely deep recreational divers go to depths of more than 200 metres, at which depths the physical and chemical properties of breathing gases create some physiological restrictions already known from professional deep diving. One risk is carbon dioxide retention due to limitation of lung ventilation caused by the high density of breathing gas mixture at great depths. This effect can be amplified by the introduction of the additional work of breathing if there is significant external resistance caused by a breathing device. The other risk for deep divers is High Pressure Neurological Syndrome (HPNS) caused by a direct compression effect, presumably on the lipid component of cell membranes of the central nervous system. In deep professional diving, divers use a mixture of helium and oxygen to decrease gas density, and nitrogen is used only in some cases for decreasing the signs and symptoms of HPNS. The same approach with decreasing the nitrogen content in the breathing mixture can also be observed nowadays in deep recreational diving. Moreover, in extremely deep professional diving, hydrogen has been used successfully both for decreasing the density of the breathing gas mixture and amelioration of HPNS signs and symptoms. It is fair to assume that the use of hydrogen will be soon "re-invented" by extremely deep recreational divers. So the scope of modern diving medicine for recreational divers should be expanded also to cover these problems, which previously were assigned exclusively to professional and military divers. PMID:22669812

  4. Physiological responses during aerobic dance of individuals grouped by aerobic capacity and dance experience.

    PubMed

    Thomsen, D; Ballor, D L

    1991-03-01

    This study examined the effects of aerobic capacity (peak oxygen uptake) and aerobic dance experience on the physiological responses to an aerobic dance routine. The heart rate (HR) and VO2 responses to three levels (intensities) of aerobic dance were measured in 27 women. Experienced aerobic dancers (AD) (mean peak VO2 = 42 ml.kg-1.min-1) were compared to subjects with limited aerobic dance experience of high (HI) (peak VO2 greater than 35 ml.kg-1.min-1) and low (LO) (peak VO2 less than 35 ml.kg-1.min-1) aerobic capacities. The results indicated the LO group exercised at a higher percentage of peak heart rate and peak VO2 at all three dance levels than did either the HI or AD groups (HI = AD). Design of aerobic dance routines must consider the exercise tolerance of the intended audience. In mixed groups, individuals with low aerobic capacities should be shown how and encouraged to modify the activity to reduce the level of exertion. PMID:2028095

  5. Blood oxygen depletion is independent of dive function in a deep diving vertebrate, the northern elephant seal.

    PubMed

    Meir, Jessica U; Robinson, Patrick W; Vilchis, L Ignacio; Kooyman, Gerald L; Costa, Daniel P; Ponganis, Paul J

    2013-01-01

    Although energetics is fundamental to animal ecology, traditional methods of determining metabolic rate are neither direct nor instantaneous. Recently, continuous blood oxygen (O2) measurements were used to assess energy expenditure in diving elephant seals (Mirounga angustirostris), demonstrating that an exceptional hypoxemic tolerance and exquisite management of blood O2 stores underlie the extraordinary diving capability of this consummate diver. As the detailed relationship of energy expenditure and dive behavior remains unknown, we integrated behavior, ecology, and physiology to characterize the costs of different types of dives of elephant seals. Elephant seal dive profiles were analyzed and O2 utilization was classified according to dive type (overall function of dive: transit, foraging, food processing/rest). This is the first account linking behavior at this level with in vivo blood O2 measurements in an animal freely diving at sea, allowing us to assess patterns of O2 utilization and energy expenditure between various behaviors and activities in an animal in the wild. In routine dives of elephant seals, the blood O2 store was significantly depleted to a similar range irrespective of dive function, suggesting that all dive types have equal costs in terms of blood O2 depletion. Here, we present the first physiological evidence that all dive types have similarly high blood O2 demands, supporting an energy balance strategy achieved by devoting one major task to a given dive, thereby separating dive functions into distinct dive types. This strategy may optimize O2 store utilization and recovery, consequently maximizing time underwater and allowing these animals to take full advantage of their underwater resources. This approach may be important to optimizing energy expenditure throughout a dive bout or at-sea foraging trip and is well suited to the lifestyle of an elephant seal, which spends > 90% of its time at sea submerged making diving its most "natural

  6. Blood Oxygen Depletion Is Independent of Dive Function in a Deep Diving Vertebrate, the Northern Elephant Seal

    PubMed Central

    Meir, Jessica U.; Robinson, Patrick W.; Vilchis, L. Ignacio; Kooyman, Gerald L.; Costa, Daniel P.; Ponganis, Paul J.

    2013-01-01

    Although energetics is fundamental to animal ecology, traditional methods of determining metabolic rate are neither direct nor instantaneous. Recently, continuous blood oxygen (O2) measurements were used to assess energy expenditure in diving elephant seals (Mirounga angustirostris), demonstrating that an exceptional hypoxemic tolerance and exquisite management of blood O2 stores underlie the extraordinary diving capability of this consummate diver. As the detailed relationship of energy expenditure and dive behavior remains unknown, we integrated behavior, ecology, and physiology to characterize the costs of different types of dives of elephant seals. Elephant seal dive profiles were analyzed and O2 utilization was classified according to dive type (overall function of dive: transit, foraging, food processing/rest). This is the first account linking behavior at this level with in vivo blood O2 measurements in an animal freely diving at sea, allowing us to assess patterns of O2 utilization and energy expenditure between various behaviors and activities in an animal in the wild. In routine dives of elephant seals, the blood O2 store was significantly depleted to a similar range irrespective of dive function, suggesting that all dive types have equal costs in terms of blood O2 depletion. Here, we present the first physiological evidence that all dive types have similarly high blood O2 demands, supporting an energy balance strategy achieved by devoting one major task to a given dive, thereby separating dive functions into distinct dive types. This strategy may optimize O2 store utilization and recovery, consequently maximizing time underwater and allowing these animals to take full advantage of their underwater resources. This approach may be important to optimizing energy expenditure throughout a dive bout or at-sea foraging trip and is well suited to the lifestyle of an elephant seal, which spends > 90% of its time at sea submerged making diving its most

  7. Use of a mobile diving support vessel, Offshore California

    SciTech Connect

    Carroll, J.P.

    1983-03-01

    The Blue Dolphin is a converted workboat with a one-atmosphere manipulator bell diving system. It provides diving support for Chevron's offshore drilling program. This support includes underwater inspection, repair and salvage.

  8. 29 CFR 1910.422 - Procedures during dive.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Commercial Diving Operations General Operations Procedures § 1910.422... applicable to each diving operation unless otherwise specified. (b) Water entry and exit. (1) A means...

  9. 29 CFR 1910.422 - Procedures during dive.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Commercial Diving Operations General Operations Procedures § 1910.422... applicable to each diving operation unless otherwise specified. (b) Water entry and exit. (1) A means...

  10. 29 CFR 1910.422 - Procedures during dive.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Commercial Diving Operations General Operations Procedures § 1910.422... applicable to each diving operation unless otherwise specified. (b) Water entry and exit. (1) A means...

  11. 29 CFR 1910.422 - Procedures during dive.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Commercial Diving Operations General Operations Procedures § 1910.422... applicable to each diving operation unless otherwise specified. (b) Water entry and exit. (1) A means...

  12. Barotrauma of the ears and sinuses after scuba diving.

    PubMed

    Becker, G D; Parell, G J

    2001-05-01

    The pathophysiology, differential diagnosis, and currently available management of barotrauma affecting the ears and sinuses after scuba diving are reviewed, along with medical standards for resuming scuba diving after barotrauma has resolved. PMID:11407445

  13. Habituation of the cardiac response to involuntary diving in diving and dabbling ducks.

    PubMed

    Gabbott, G R; Jones, D R

    1987-09-01

    1. Bradycardia in response to forced submergence was habituated in dabbling (Anas platyrhynchos, Linnaeus) and diving (Aythya americana, Eyton) ducks by repetitively submerging the animals, each day for several days, for periods of 40 and 20 s, respectively. The onset of pronounced bradycardia was delayed with each successive trial, until little or no bradycardia occurred during submergence. Diving bradycardia is driven by chemoreceptors in the dabbler and caused by stimulation of narial receptors in the diver. 2. Mean arterial blood pressure in dives was unchanged from pre-dive levels in both naive and trained dabbling ducks. PaO2, PaCO2 and pHa at the end of a dive were similar before and after habituation training. 3. Bradycardia occurred in dives by habituated dabbling ducks if the animal breathed 15% O2 before submergence. The ventilatory responses to breathing high and low levels of oxygen were unaffected by habituation training. 4. The changes in blood gases during dives by naive and habituated dabbling ducks were the same: therefore, in the absence of a demonstrated decrement in receptor chemosensitivity or efferent potency, the locus of habituation must reside in the central nervous system. PMID:3694117

  14. WWOX loss activates aerobic glycolysis

    PubMed Central

    Abu-Remaileh, Muhannad; Seewaldt, Victoria L; Aqeilan, Rami I

    2015-01-01

    Cancer cells undergo reprogramming of glucose metabolism to limit energy production to glycolysis—a state known as “aerobic glycolysis.” Hypoxia-inducible factor 1 (HIF1α) is a transcription factor that regulates many genes responsible for this switch. As discussed here, new data suggest that the tumor suppressor WW domain-containing oxidoreductase (WWOX) modulates HIF1α, thereby regulating this metabolic state. PMID:27308416

  15. The physiology and pathophysiology of human breath-hold diving.

    PubMed

    Lindholm, Peter; Lundgren, Claes E G

    2009-01-01

    This is a brief overview of physiological reactions, limitations, and pathophysiological mechanisms associated with human breath-hold diving. Breath-hold duration and ability to withstand compression at depth are the two main challenges that have been overcome to an amazing degree as evidenced by the current world records in breath-hold duration at 10:12 min and depth of 214 m. The quest for even further performance enhancements continues among competitive breath-hold divers, even if absolute physiological limits are being approached as indicated by findings of pulmonary edema and alveolar hemorrhage postdive. However, a remarkable, and so far poorly understood, variation in individual disposition for such problems exists. Mortality connected with breath-hold diving is primarily concentrated to less well-trained recreational divers and competitive spearfishermen who fall victim to hypoxia. Particularly vulnerable are probably also individuals with preexisting cardiac problems and possibly, essentially healthy divers who may have suffered severe alternobaric vertigo as a complication to inadequate pressure equilibration of the middle ears. The specific topics discussed include the diving response and its expression by the cardiovascular system, which exhibits hypertension, bradycardia, oxygen conservation, arrhythmias, and contraction of the spleen. The respiratory system is challenged by compression of the lungs with barotrauma of descent, intrapulmonary hemorrhage, edema, and the effects of glossopharyngeal insufflation and exsufflation. Various mechanisms associated with hypoxia and loss of consciousness are discussed, including hyperventilation, ascent blackout, fasting, and excessive postexercise O(2) consumption. The potential for high nitrogen pressure in the lungs to cause decompression sickness and N(2) narcosis is also illuminated. PMID:18974367

  16. [Complex profile of the reflex diving response].

    PubMed

    Wierzba, Tomasz H; Ropiak, Arkadiusz

    2011-01-01

    Breath-holding coupled with face cooling triggers a set of the reflex cardiovascular responses, defined as a diving reflex. The major reflex responses include a decrease in heart rate and peripheral vasoconstriction with an increase of arterial pressure to evoke central blood pooling with preferential provision of the brain and heart perfusion. Due to high individual variability and situational dependence the individual course of the reflex response is hardly predictable. Heart rhythm disturbances are the major, sometimes fatal complications of the response. This review is an outline of causing factors, circumstances, mechanisms and the effects of the diving reflex and their practical implications, including risk factors of the critical arrhythmias occurred in diving. PMID:22125213

  17. 29 CFR 1926.1086 - Mixed-gas diving.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 8 2011-07-01 2011-07-01 false Mixed-gas diving. 1926.1086 Section 1926.1086 Labor... (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving Specific Operations Procedures § 1926.1086 Mixed-gas diving. Note: The requirements applicable to construction work under this section...

  18. 29 CFR 1910.425 - Surface-supplied air diving.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 5 2011-07-01 2011-07-01 false Surface-supplied air diving. 1910.425 Section 1910.425..., DEPARTMENT OF LABOR OCCUPATIONAL SAFETY AND HEALTH STANDARDS Commercial Diving Operations Specific Operations Procedures § 1910.425 Surface-supplied air diving. (a) General. Employers engaged in surface-supplied...

  19. 46 CFR 197.334 - Open diving bells.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Open diving bells. 197.334 Section 197.334 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE OCCUPATIONAL SAFETY AND HEALTH STANDARDS GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.334 Open diving bells. Each open...

  20. 29 CFR 1926.1085 - Surface-supplied air diving.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Surface-supplied air diving. 1926.1085 Section 1926.1085..., DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving Specific Operations Procedures § 1926.1085 Surface-supplied air diving. Note: The requirements applicable to construction...

  1. 29 CFR 1915.6 - Commerical diving operations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Commerical diving operations. 1915.6 Section 1915.6 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Commerical diving operations. Commerical diving operations shall be subject to subpart T of part...

  2. 29 CFR 1926.1086 - Mixed-gas diving.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Mixed-gas diving. 1926.1086 Section 1926.1086 Labor... (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving Specific Operations Procedures § 1926.1086 Mixed-gas diving. Note: The requirements applicable to construction work under this section...

  3. 29 CFR 1926.1085 - Surface-supplied air diving.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 8 2011-07-01 2011-07-01 false Surface-supplied air diving. 1926.1085 Section 1926.1085..., DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving Specific Operations Procedures § 1926.1085 Surface-supplied air diving. Note: The requirements applicable to construction...

  4. 46 CFR 56.50-110 - Diving support systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Diving support systems. 56.50-110 Section 56.50-110... APPURTENANCES Design Requirements Pertaining to Specific Systems § 56.50-110 Diving support systems. (a) In addition to the requirements of this part, piping for diving installations which is permanently...

  5. 29 CFR 1910.425 - Surface-supplied air diving.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 5 2010-07-01 2010-07-01 false Surface-supplied air diving. 1910.425 Section 1910.425..., DEPARTMENT OF LABOR OCCUPATIONAL SAFETY AND HEALTH STANDARDS Commercial Diving Operations Specific Operations Procedures § 1910.425 Surface-supplied air diving. (a) General. Employers engaged in surface-supplied...

  6. 46 CFR 56.50-110 - Diving support systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Diving support systems. 56.50-110 Section 56.50-110... APPURTENANCES Design Requirements Pertaining to Specific Systems § 56.50-110 Diving support systems. (a) In addition to the requirements of this part, piping for diving installations which is permanently...

  7. 46 CFR 197.334 - Open diving bells.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Open diving bells. 197.334 Section 197.334 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE OCCUPATIONAL SAFETY AND HEALTH STANDARDS GENERAL PROVISIONS Commercial Diving Operations Equipment § 197.334 Open diving bells. Each open...

  8. 29 CFR 1915.6 - Commerical diving operations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 7 2011-07-01 2011-07-01 false Commerical diving operations. 1915.6 Section 1915.6 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Commerical diving operations. Commerical diving operations shall be subject to subpart T of part...

  9. 29 CFR 1910.422 - Procedures during dive.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 5 2012-07-01 2012-07-01 false Procedures during dive. 1910.422 Section 1910.422 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR OCCUPATIONAL SAFETY AND HEALTH STANDARDS Commercial Diving Operations General Operations Procedures § 1910.422 Procedures during dive....

  10. 29 CFR 1926.1086 - Mixed-gas diving.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 8 2012-07-01 2012-07-01 false Mixed-gas diving. 1926.1086 Section 1926.1086 Labor... (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving Specific Operations Procedures § 1926.1086 Mixed-gas diving. Note: The requirements applicable to construction work under this section...

  11. 46 CFR 56.50-110 - Diving support systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Diving support systems. 56.50-110 Section 56.50-110... APPURTENANCES Design Requirements Pertaining to Specific Systems § 56.50-110 Diving support systems. (a) In addition to the requirements of this part, piping for diving installations which is permanently...

  12. 29 CFR 1915.6 - Commerical diving operations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 7 2012-07-01 2012-07-01 false Commerical diving operations. 1915.6 Section 1915.6 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Commerical diving operations. Commerical diving operations shall be subject to subpart T of part...

  13. 29 CFR 1926.1086 - Mixed-gas diving.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 8 2013-07-01 2013-07-01 false Mixed-gas diving. 1926.1086 Section 1926.1086 Labor... (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving Specific Operations Procedures § 1926.1086 Mixed-gas diving. Note: The requirements applicable to construction work under this section...

  14. 46 CFR 56.50-110 - Diving support systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Diving support systems. 56.50-110 Section 56.50-110... APPURTENANCES Design Requirements Pertaining to Specific Systems § 56.50-110 Diving support systems. (a) In addition to the requirements of this part, piping for diving installations which is permanently...

  15. 29 CFR 1915.6 - Commerical diving operations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 7 2013-07-01 2013-07-01 false Commerical diving operations. 1915.6 Section 1915.6 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Commerical diving operations. Commerical diving operations shall be subject to subpart T of part...

  16. 29 CFR 1926.1085 - Surface-supplied air diving.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 8 2014-07-01 2014-07-01 false Surface-supplied air diving. 1926.1085 Section 1926.1085..., DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving Specific Operations Procedures § 1926.1085 Surface-supplied air diving. Note: The requirements applicable to construction...

  17. 46 CFR 56.50-110 - Diving support systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Diving support systems. 56.50-110 Section 56.50-110... APPURTENANCES Design Requirements Pertaining to Specific Systems § 56.50-110 Diving support systems. (a) In addition to the requirements of this part, piping for diving installations which is permanently...

  18. 29 CFR 1926.1086 - Mixed-gas diving.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 8 2014-07-01 2014-07-01 false Mixed-gas diving. 1926.1086 Section 1926.1086 Labor... (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving Specific Operations Procedures § 1926.1086 Mixed-gas diving. Note: The requirements applicable to construction work under this section...

  19. 29 CFR 1915.6 - Commerical diving operations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 7 2014-07-01 2014-07-01 false Commerical diving operations. 1915.6 Section 1915.6 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Commerical diving operations. Commerical diving operations shall be subject to subpart T of part...

  20. 46 CFR 197.432 - Surface-supplied air diving.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... at depths less than 190 fsw, except that dives with bottom times of 30 minutes or less may be conducted to depths of 220 fsw; (b) Each diving operation has a primary breathing gas supply; (c) Each diver... deeper than 130 fsw or outside the no-decompression limits— (1) Each diving operation has a...

  1. 29 CFR 1910.425 - Surface-supplied air diving.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-supplied air diving shall not be conducted at depths deeper than 190 fsw, except that dives with bottom times of 30 minutes or less may be conducted to depths of 220 fsw. (2) A decompression chamber shall be... fsw. (3) A bell shall be used for dives with an inwater decompression time greater than 120...

  2. 29 CFR 1910.421 - Pre-dive procedures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 5 2010-07-01 2010-07-01 false Pre-dive procedures. 1910.421 Section 1910.421 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR OCCUPATIONAL SAFETY AND HEALTH STANDARDS Commercial Diving Operations General Operations Procedures § 1910.421 Pre-dive procedures. (a)...

  3. 29 CFR 1910.421 - Pre-dive procedures.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 5 2012-07-01 2012-07-01 false Pre-dive procedures. 1910.421 Section 1910.421 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR OCCUPATIONAL SAFETY AND HEALTH STANDARDS Commercial Diving Operations General Operations Procedures § 1910.421 Pre-dive procedures. (a)...

  4. 29 CFR 1910.421 - Pre-dive procedures.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 5 2011-07-01 2011-07-01 false Pre-dive procedures. 1910.421 Section 1910.421 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR OCCUPATIONAL SAFETY AND HEALTH STANDARDS Commercial Diving Operations General Operations Procedures § 1910.421 Pre-dive procedures. (a)...

  5. Effects of scuba diving on vascular repair mechanisms.

    PubMed

    Culic, Vedrana Cikes; Van Craenenbroeck, Emeline; Muzinic, Nikolina Rezic; Ljubkovic, Marko; Marinovic, Jasna; Conraads, Viviane; Dujic, Zeljko

    2014-01-01

    A single air dive causes transient endothelial dysfunction. Endothelial progenitor cells (EPCs) and circulating angiogenic cells (CAC) contribute synergistically to endothelial repair. In this study (1) the acute effects of diving on EPC numbers and CAC migration and (2) the influence of the gas mixture (air/nitrox-36) was investigated. Ten divers performed two dives to 18 meters on Day (D) 1 and D3, using air. After 15 days, dives were repeated with nitrox-36. Blood sampling took place before and immediately after diving. Circulating EPCs were quantified by flow cytometry, CAC migration of culture was assessed on D7. When diving on air, a trend for reduced EPC numbers is observed post-dive, which is persistent on D1 and D3. CAC migration tends to improve acutely following diving. These effects are more pronounced with nitrox-36 dives. Diving acutely affects EPC numbers and CAC function, and to a larger extent when diving with nitrox-36. The diving-induced oxidative stress may influence recruitment or survival of EPC. The functional improvement of CAC could be a compensatory mechanism to maintain endothelial homeostasis. PMID:24851546

  6. Diving into the Ice Bucket Challenge

    PubMed Central

    McKee, Kathleen; Batra, Ayush; Klein, Joshua P.; Henderson, Galen V.

    2015-01-01

    Triggered by facial exposure to cold water and apnea, the mammalian diving reflex consists of bradycardia and peripheral arteriolar vasoconstriction leading to an increase in central arterial pressure. It has been previously associated with ischemic stroke but not definitively with intracerebral hemorrhage. We present a case of intracerebral hemorrhage occurring in a woman with poorly controlled hypertension following her participation in the amyotrophic lateral sclerosis fund-raising “Ice Bucket Challenge,” in which ice-cold water was poured on her head. We suspect that facial exposure to ice-cold water triggered the diving reflex, causing a hypertensive surge and ultimately the intracerebral hemorrhage. PMID:26288676

  7. 76 FR 8917 - Special Conditions: Gulfstream Model GVI Airplane; Automatic Speed Protection for Design Dive Speed

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-16

    ...; Automatic Speed Protection for Design Dive Speed AGENCY: Federal Aviation Administration (FAA), DOT. ACTION... design features include a high speed protection system. These proposed special conditions contain the... Design Features The GVI is equipped with a high speed protection system that limits nose down...

  8. Metabolic responses to forced dives in Pekin duck measured by indirect calorimetry and 31P-MRS.

    PubMed

    Stephenson, R; Jones, D R

    1992-12-01

    We tested the hypothesis that forced-dived ducks experience a reduction in metabolic rate during prolonged submergence. Unidirectionally ventilated conscious ducks were subjected to forced dives by temporarily stopping the airflow in the ventilation system and simultaneously filling a face mask with cold water. A typical cardiovascular response to submergence was observed: bradycardia and maintained arterial blood pressure. Phosphorylated metabolite concentrations in the pectoral muscle were measured noninvasively by phosphorus magnetic resonance spectroscopy (31P-MRS). ATP content was constant, and phosphocreatine was depleted via the creatine kinase reaction at a rate similar to the resting rate of ATP turnover, which was estimated to be 0.9 mumol.min-1 x g-1 in resting perfused pectoral muscle of pentobarbital-anesthetized ducks. Oxygen from myoglobin supplied at most 12% of the ATP required by the resting muscle during dives. Whole animal postdive excess oxygen consumption and blood lactic acid accumulation suggested that the shortfall in aerobic metabolism during forced dives was compensated by an increase in anaerobic metabolism. PMID:1481944

  9. [Scuba diving and the heart. Cardiac aspects of sport scuba diving].

    PubMed

    Muth, Claus-Martin; Tetzlaff, Kay

    2004-06-01

    Diving with self-contained underwater breathing apparatus (scuba) has become a popular recreational sports activity throughout the world. A high prevalence of cardiovascular disorders among the population makes it therefore likely that subjects suffering from cardiovascular problems may want to start scuba diving. Although scuba diving is not a competitive sport requiring athletic health conditions, a certain medical fitness is recommended because of the physical peculiarities of the underwater environment. Immersion alone will increase cardiac preload by central blood pooling with a rise in both cardiac output and blood pressure, counteracted by increased diuresis. Exposure to cold and increased oxygen partial pressure during scuba diving will additionally increase afterload by vasoconstrictive effects and may exert bradyarryhthmias in combination with breath-holds. Volumes of gas-filled body cavities will be affected by changing pressure (Figure 1), and inert gas components of the breathing gas mixture such as nitrogen in case of air breathing will dissolve in body tissues and venous blood with increasing alveolar inert gas pressure. During decompression a free gas phase may form in supersaturated tissues, resulting in the generation of inert gas microbubbles that are eliminated by the venous return to the lungs under normal circumstances. Certain cardiovascular conditions may have an impact on these physiological changes and pose the subject at risk of suffering adverse events from scuba diving. Arterial hypertension may be aggravated by underwater exercise and immersion. Symptomatic coronary artery disease and symptomatic heart rhythm disorders preclude diving. The occurrence of ventricular extrasystoles according to Lown classes I and II, and the presence of atrial fibrillation are considered relative contraindications in the absence of an aggravation following exercise. Asymptomatic subjects with Wolff-Parkinson-White syndrome may be allowed to dive, but in

  10. [Health aspects of diving in ENT medicine. Part I: Diving associated diseases].

    PubMed

    Klingmann, C; Wallner, F

    2004-08-01

    There has been a steady increase in the number of recreational scuba divers in the last years, with a growing number of diving associated diseases involving ENT medicine. Disorders of the ears, sinuses and pharynx are those most common in divers. In particular, external otitis and barotrauma of the middle ear are commonly treated by every ENT specialist. They usually do not lead to any permanent complaints. Incidents involving the cochleovestibular system are less common, but can result in deafness, vertigo and tinnitus, and therefore have to be treated appropriately. To treat diving medical disorders, the physician has to have some basic understanding of the physical laws that lead to diving incidents. This article will inform the reader of the forces that are encountered by divers, and then give details of the treatment of acute ENT diseases which result from diving incidents. PMID:15221085

  11. Management of aerobic vaginitis.

    PubMed

    Tempera, Gianna; Furneri, Pio Maria

    2010-01-01

    Aerobic vaginitis is a new nonclassifiable pathology that is neither specific vaginitis nor bacterial vaginosis. The diversity of this microbiological peculiarity could also explain several therapeutic failures when patients were treated for infections identified as bacterial vaginosis. The diagnosis 'aerobic vaginitis' is essentially based on microscopic examinations using a phase-contrast microscope (at ×400 magnification). The therapeutic choice for 'aerobic vaginitis' should take into consideration an antibiotic characterized by an intrinsic activity against the majority of bacteria of fecal origin, bactericidal effect and poor/absent interference with the vaginal microbiota. Regarding the therapy for aerobic vaginitis when antimicrobial agents are prescribed, not only the antimicrobial spectrum but also the presumed ecological disturbance on the anaerobic and aerobic vaginal and rectal microbiota should be taken into a consideration. Because of their very low impact on the vaginal microbiota, kanamycin or quinolones are to be considered a good choice for therapy. PMID:21051843

  12. Experiment of nitrox saturation diving with trimix excursion.

    PubMed

    Shi, Z Y

    1998-11-01

    Depth limitations to diving operation with air as the breathing gas are well known: air density, oxygen toxicity, nitrogen narcosis and requirement for decompression. The main objectives of our experiment were to assess the decompression, counterdiffusion and performance aspect of helium-nitrogen-oxygen excursions from nitrox saturation. The experiment was carried out in a wet diving stimulator with "igloo" attached to a 2-lock living chamber. Four subjects of two teams of 2 divers were saturated at 25 msw simulated depth in a nitrogen oxygen chamber environment for 8 days, during which period they performed 32 divers-excursions to 60 or 80 msw pressure. Excursion gas mix was trimix of 14.6% oxygen, 50% helium and 35.4% nitrogen, which gave a bottom oxygen partial pressure of 1.0 bars at 60 msw and 1.3 at 80 msw. Excursions were for 70 min at 60 msw with three 10-min work periods and 40 min at 80 msw with two 10-min work periods. Work was on a bicycle ergometer at a moderate level. We calculated the excursion decompression with M-Values based on methods of Hamilton (Hamilton et al., 1990). Staged decompression took 70 min for the 60 msw excursion and 98 min for 80 msw, with stops beginning at 34 or 43 msw respectively. After the second dive day bubbles were heard mainly in one diver but in three divers overall, to Spencer Grade III some times. No symptoms were reported. Saturation decompression using the Repex procedures began at 40 msw and was uneventful: Grade II and sometimes III bubbles persisted in 2 of the four divers until 24 hr after surfacing. We conclude that excursions with mixture rich in helium can be performed effectively to as deep as 80 msw using these procedures. PMID:10052222

  13. The dive response redefined: underwater behavior influences cardiac variability in freely diving dolphins.

    PubMed

    Noren, Shawn R; Kendall, Traci; Cuccurullo, Veronica; Williams, Terrie M

    2012-08-15

    A hallmark of the dive response, bradycardia, promotes the conservation of onboard oxygen stores and enables marine mammals to submerge for prolonged periods. A paradox exists when marine mammals are foraging underwater because activity should promote an elevation in heart rate (f(H)) to support increased metabolic demands. To assess the effect of the interaction between the diving response and underwater activity on f(H), we integrated interbeat f(H) with behavioral observations of adult bottlenose dolphins diving and swimming along the coast of the Bahamas. As expected for the dive response, f(H) while resting during submergence (40±6 beats min(-1)) was significantly lower than f(H) while resting at the water surface (105±8 beats min(-1)). The maximum recorded f(H) (f(H,max)) was 128±7 beats min(-1), and occurred during post-dive surface intervals. During submergence, the level of bradycardia was modified by activity. Behaviors such as simple head bobbing at depth increased f(H) by 40% from submerged resting levels. Higher heart rates were observed for horizontal swimming at depth. Indeed, the dolphins operated at 37-58% of their f(H,max) while active at depth and approached 57-79% of their f(H,max) during anticipatory tachycardia as the animals glided to the surface. f(H) was significantly correlated with stroke frequency (range=0-2.5 strokes s(-1), r=0.88, N=25 dives) and calculated swim speed (range=0-5.4 m s(-1), r=0.88, N=25 dives). We find that rather than a static reflex, the dive response is modulated by behavior and exercise in a predictable manner. PMID:22837445

  14. 46 CFR 197.410 - Dive procedures.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... of decompression sickness prior to each dive; (4) A depth, bottom time profile, including any... sickness or gas embolism; (iii) The diver is advised of the location of an operational decompression... decompression chamber; and (9) When decompression sickness or gas embolism is suspected or symptoms are...

  15. 46 CFR 197.410 - Dive procedures.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... of decompression sickness prior to each dive; (4) A depth, bottom time profile, including any... sickness or gas embolism; (iii) The diver is advised of the location of an operational decompression... decompression chamber; and (9) When decompression sickness or gas embolism is suspected or symptoms are...

  16. 46 CFR 197.410 - Dive procedures.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... of decompression sickness prior to each dive; (4) A depth, bottom time profile, including any... sickness or gas embolism; (iii) The diver is advised of the location of an operational decompression... decompression chamber; and (9) When decompression sickness or gas embolism is suspected or symptoms are...

  17. 46 CFR 197.410 - Dive procedures.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... of decompression sickness prior to each dive; (4) A depth, bottom time profile, including any... sickness or gas embolism; (iii) The diver is advised of the location of an operational decompression... decompression chamber; and (9) When decompression sickness or gas embolism is suspected or symptoms are...

  18. [Case Report - Really a diving accident?].

    PubMed

    Fichtner, Andreas

    2015-10-01

    A 17 y old male SCUBA diver presents himself for hospital admission after a suspected diving accident. All clinical signs are favouring the initial diagnosis: loss of leg motor function, paresthesia, disturbed vision and headache. What are your further diagnostic and therapeutic steps? Can you proof the initial diagnosis? What differential diagnoses are relevant or even mimicked? PMID:26510103

  19. Sphenoid sinus barotrauma after free diving.

    PubMed

    Bourolias, Constantinos; Gkotsis, Antonios

    2011-01-01

    We report 2 cases of a 29- and a 37-year-old male patient both having sphenoid sinus barotrauma associated with free diving at about 12-m depth. A unilateral occupation of the sphenoid sinus was revealed in both cases by computed tomography and magnetic resonance imaging examination of the paranasal sinuses. PMID:20022669

  20. [Injuries caused by pressure differences while diving].

    PubMed

    Kemmer, A; Welslau, W; Muth, C M

    2005-07-01

    Barotraumas are caused by pressure differences. As described by Boyle's Law, barotraumas develop during the descent phase of diving (and much more rarely during the ascent). The most frequently affected are the ears and paranasal sinuses, in addition to the facial skin and eyes. The most important preventive measure is performing pressure compensation in the affected body cavities. Barotrauma is treated symptomatically. PMID:16041937

  1. Diving behaviour and heart rate in tufted ducks (Aythya fuligula).

    PubMed

    Stephenson, R; Butler, P J; Woakes, A J

    1986-11-01

    Diving behaviour and heart rate were monitored in tufted ducks diving under circumstances which simulated various environmental conditions such as feeding under ice in winter. When distance to food was increased on a covered outdoor pond, dive duration increased proportionately, but it was calculated that time available for feeding was reduced during the longer-distance 'extended' dives. There was a gradual reduction in heart rate to 77.3 +/- 13.8 beats min-1, which is significantly lower than the resting value of 121.1 +/- 14.1 beats min-1, during the course of extended dives, suggesting that the ducks could gradually switch over to a 'classical' oxygen-conserving response during these prolonged voluntary dives. The duration of the pre-dive preparatory period was positively correlated with dive distance. When the ducks were briefly unable to resurface during an otherwise normal feeding dive in an indoor tank, a situation which may occur if they become disoriented under ice, there was an immediate switch to a full bradycardia. Reduction in heart rate during these 'enclosed' dives occurred only when the ducks were apparently aware of the situation and the rate of onset of bradycardia was very similar to that previously observed during involuntary submersion of tufted ducks. Minimum heart rate was the same at 46 beats min-1 after 15 s of enclosed dives and after 30 s of involuntary submersions, despite the differences in levels of activity in the two situations. PMID:3805996

  2. Effects of Long-term Diving Training on Cortical Gyrification

    PubMed Central

    Zhang, Yuanchao; Zhao, Lu; Bi, Wenwei; Wang, Yue; Wei, Gaoxia; Evans, Alan; Jiang, Tianzi

    2016-01-01

    During human brain development, cortical gyrification, which is believed to facilitate compact wiring of neural circuits, has been shown to follow an inverted U-shaped curve, coinciding with the two-stage neurodevelopmental process of initial synaptic overproduction with subsequent pruning. This trajectory allows postnatal experiences to refine the wiring, which may manifest as endophenotypic changes in cortical gyrification. Diving experts, typical elite athletes who commence intensive motor training at a very young age in their early childhood, serve ideal models for examining the gyrification changes related to long-term intensive diving training. Using local gyrification index (LGI), we compared the cortical gyrification between 12 diving experts and 12 controls. Compared with controls, diving experts showed widespread LGI reductions in regions relevant to diving performance. Negative correlations between LGIs and years of diving training were also observed in diving experts. Further exploratory network efficiency analysis of structural cortical networks, inferred from interregional correlation of LGIs, revealed comparable global and local efficiency in diving experts relative to controls. These findings suggest that gyrification reductions in diving experts may be the result of long-term diving training which could refine the neural circuitry (via synaptic pruning) and might be the anatomical substrate underlying their extraordinary diving performance. PMID:27320849

  3. Statistical correlations and risk analyses techniques for a diving dual phase bubble model and data bank using massively parallel supercomputers.

    PubMed

    Wienke, B R; O'Leary, T R

    2008-05-01

    Linking model and data, we detail the LANL diving reduced gradient bubble model (RGBM), dynamical principles, and correlation with data in the LANL Data Bank. Table, profile, and meter risks are obtained from likelihood analysis and quoted for air, nitrox, helitrox no-decompression time limits, repetitive dive tables, and selected mixed gas and repetitive profiles. Application analyses include the EXPLORER decompression meter algorithm, NAUI tables, University of Wisconsin Seafood Diver tables, comparative NAUI, PADI, Oceanic NDLs and repetitive dives, comparative nitrogen and helium mixed gas risks, USS Perry deep rebreather (RB) exploration dive,world record open circuit (OC) dive, and Woodville Karst Plain Project (WKPP) extreme cave exploration profiles. The algorithm has seen extensive and utilitarian application in mixed gas diving, both in recreational and technical sectors, and forms the bases forreleased tables and decompression meters used by scientific, commercial, and research divers. The LANL Data Bank is described, and the methods used to deduce risk are detailed. Risk functions for dissolved gas and bubbles are summarized. Parameters that can be used to estimate profile risk are tallied. To fit data, a modified Levenberg-Marquardt routine is employed with L2 error norm. Appendices sketch the numerical methods, and list reports from field testing for (real) mixed gas diving. A Monte Carlo-like sampling scheme for fast numerical analysis of the data is also detailed, as a coupled variance reduction technique and additional check on the canonical approach to estimating diving risk. The method suggests alternatives to the canonical approach. This work represents a first time correlation effort linking a dynamical bubble model with deep stop data. Supercomputing resources are requisite to connect model and data in application. PMID:18371945

  4. Oxygen uptake during post dive recovery in a diving bird Aythya fuligula: implications for optimal foraging models.

    PubMed

    Parkes, Roland; Halsey, Lewis G; Woakes, Anthony J; Holder, Roger L; Butler, Patrick J

    2002-12-01

    The rate of oxygen uptake at the surface between dives was measured for four tufted ducks, Aythya fuligula, during bouts of foraging dives to a depth of 1.8 m. The ducks surfaced into a respirometer box after each dive so that the rate of oxygen uptake ((O(2))) could be measured. (O(2)) decreased over time at the surface and there was a particularly rapid phase of oxygen uptake for approximately the first 3s. The specific shape of the oxygen uptake curve is dependent upon the duration of the preceding dive. The uptake curve after longer dives was significantly steeper during the first 3s at the surface than after shorter dives, although (O(2)) after the first 3s was not significantly different between these two dive duration bins. Thus, the mean total oxygen uptake (V(O(2))) was higher after surface periods following longer dives. Due to the high (O(2)) during the initial part of the surface period, the curve associated with longer dives was statistically biphasic, with the point of inflection at 3.3s. The curve for shorter dives was not statistically biphasic. The birds may increase their respiratory frequency during the first 3s after longer dives, producing the increased (O(2)), which would enable the birds to resaturate their oxygen stores more rapidly in response to the increased oxygen depletion of the longer submergence time. PMID:12432016

  5. [Hyperbaric therapy and diving medicine - diving medicine - present state and prospects].

    PubMed

    Winkler, Bernd; Muth, Claus-Martin; Piepho, Tim

    2015-10-01

    The diving accident (decompression incident, DCI) occurs in the decompression phase of dives. The DCI can either be caused by an arterial gas embolism (AGE) subsequent to a pulmonary barotrauma or by the formation of inert gas bubbles subsequent to a reduction of ambient pressure during the ascent from depth. In contrast to the traditional assumption that decompression incidents only occur if decompression rules are neglected, recent data indicate that a vast amount of diving accidents occur even though divers adhered to the rules. Hence, there is a large inter- and intraindividual variability in the predisposition for diving accidents. Within the past few years, the molecular understanding of the pathophysiology of diving accidents has improved considerably. It is now well accepted that pro-inflammatory and pro-coagulatory mechanisms play a central role. Moreover, microparticles are increasingly discussed in the pathogenesis of diving accidents. These new molecular findings have not yet resulted in new therapeutic approaches. However, new approaches of preconditioning before the dive have been developed which are intended to reduce the risk of diving accidents. The symptoms of a diving accident show a large variability and range. They reach from pruritus over tension in the female breast, marbled skin and pain in the joints to severe neurological disability like paraplegia or hemiplegia. Furthermore, pulmonary symptoms can be a result of a pulmonary gas embolism and/or a tension pneumothorax. Extreme cases can also manifest as generalized, difficult-to-treat seizures, loss of consciousness or even death. The evidence-based therapy of diving accidents consists of an immediate application of 100% inspiratory O2. This can be performed via a demand valve, face mask with reservoir bag or ventilation bag connected to a reservoir bag. Fluid substitution is performed by i. v. infusion of 500-1000ml/h of cristalloids. If consciousness is not impaired, the diver is

  6. Calling under pressure: short-finned pilot whales make social calls during deep foraging dives

    PubMed Central

    Jensen, Frants H.; Perez, Jacobo Marrero; Johnson, Mark; Soto, Natacha Aguilar; Madsen, Peter T.

    2011-01-01

    Toothed whales rely on sound to echolocate prey and communicate with conspecifics, but little is known about how extreme pressure affects pneumatic sound production in deep-diving species with a limited air supply. The short-finned pilot whale (Globicephala macrorhynchus) is a highly social species among the deep-diving toothed whales, in which individuals socialize at the surface but leave their social group in pursuit of prey at depths of up to 1000 m. To investigate if these animals communicate acoustically at depth and test whether hydrostatic pressure affects communication signals, acoustic DTAGs logging sound, depth and orientation were attached to 12 pilot whales. Tagged whales produced tonal calls during deep foraging dives at depths of up to 800 m. Mean call output and duration decreased with depth despite the increased distance to conspecifics at the surface. This shows that the energy content of calls is lower at depths where lungs are collapsed and where the air volume available for sound generation is limited by ambient pressure. Frequency content was unaffected, providing a possible cue for group or species identification of diving whales. Social calls may be important to maintain social ties for foraging animals, but may be impacted adversely by vessel noise. PMID:21345867

  7. Limiter

    DOEpatents

    Cohen, S.A.; Hosea, J.C.; Timberlake, J.R.

    1984-10-19

    A limiter with a specially contoured front face is provided. The front face of the limiter (the plasma-side face) is flat with a central indentation. In addition, the limiter shape is cylindrically symmetric so that the limiter can be rotated for greater heat distribution. This limiter shape accommodates the various power scrape-off distances lambda p, which depend on the parallel velocity, V/sub parallel/, of the impacting particles.

  8. Passive acoustic detection of deep-diving beaked whales.

    PubMed

    Zimmer, Walter M X; Harwood, John; Tyack, Peter L; Johnson, Mark P; Madsen, Peter T

    2008-11-01

    Beaked whales can remain submerged for an hour or more and are difficult to sight when they come to the surface to breathe. Passive acoustic detection (PAD) not only complements traditional visual-based methods for detecting these species but also can be more effective because beaked whales produce clicks regularly to echolocate on prey during deep foraging dives. The effectiveness of PAD for beaked whales depends not only on the acoustic behavior and output of the animals but also on environmental conditions and the quality of the passive sonar implemented. A primary constraint on the range at which beaked whale clicks can be detected involves their high frequencies, which attenuate rapidly, resulting in limited ranges of detection, especially in adverse environmental conditions. Given current knowledge of source parameters and in good conditions, for example, with a wind speed of 2 ms, a receiver close to the surface should be able to detect acoustically Cuvier's beaked whales with a high probability at distances up to 0.7 km, provided the listening duration exceeds the deep dive interval, about 2.5 h on average. Detection ranges beyond 4 km are unlikely and would require low ambient noise or special sound propagation conditions. PMID:19045770

  9. Teaching Aerobic Lifestyles: New Perspectives.

    ERIC Educational Resources Information Center

    Goodrick, G. Ken; Iammarino, Nicholas K.

    1982-01-01

    New approaches to teaching aerobic life-styles in secondary schools are suggested, focusing on three components: (1) the psychological benefits of aerobic activity; (2) alternative aerobic programs at nonschool locations; and (3) the development of an aerobics curriculum to help maintain an active life-style after graduation. (JN)

  10. Aerobic Conditioning Class.

    ERIC Educational Resources Information Center

    Johnson, Neil R.

    1980-01-01

    An aerobic exercise class that focuses on the conditioning of the cardiovascular and muscular systems is presented. Students complete data cards on heart rate, pulse, and exercises to be completed during the forty minute course. (CJ)

  11. Hormonal regulatory adjustments during voluntary diving in Weddell seals.

    PubMed

    Hochachka, P W; Liggins, G C; Guyton, G P; Schneider, R C; Stanek, K S; Hurford, W E; Creasy, R K; Zapol, D G; Zapol, W M

    1995-10-01

    Subadult male Weddell seals were instrumented with microcomputer-based backpacks and were then monitored during voluntary diving and recovery periods in McMurdo Sound, Antarctica. Depth and duration of diving, swim speed, and dive pattern were routinely monitored. An indwelling venous catheter was used to collect plasma samples at various time periods before and following diving episodes, so that changes in plasma concentrations of hormones and of metabolites could be measured. Adrenergic and nitroxidergic regulatory effects were assessed indirectly by measuring concentration changes in catecholamine and cyclic guanosine monophosphate (cGMP), respectively. The studies found that (i), except for dives of less than several minutes, epinephrine and norepinephrine both increased as a function of diving duration, then rapidly decreased during recovery (with a half time of about 10 min), (ii) that the changes in catecholamine concentrations correlated with splenic contraction and an increase in circulating red blood cell mass (hematocrit), (iii) that the changes in catecholamines, especially [epinephrine], were inversely related to insulin/glucagon ratios, which mediated a postdiving hyperglycemia, and (iv) that in long dives (but not short ones) the changes in catecholamines correlated with increasing reliance on anaerobic metabolism, indicated by increased plasma lactate concentrations. These diving-catecholamine relationships during voluntary diving at sea were similar to those observed during enforced submergence (simulated diving) under controlled laboratory conditions. At the end of diving, even while catecholamine concentrations were still high, many of the above effects were rapidly reversed and the reversal appeared to correlate with accelerated nitric oxide production, indirectly indicated by increased plasma cGMP concentrations. Taken together, the data led to the hypothesis of important adrenergic regulation of the diving response in seals, with rapid

  12. 46 CFR 197.434 - Surface-supplied mixed-gas diving.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Surface-supplied mixed-gas diving. 197.434 Section 197... HEALTH STANDARDS GENERAL PROVISIONS Commercial Diving Operations Specific Diving Mode Procedures § 197.434 Surface-supplied mixed-gas diving. The diving supervisor shall insure that— (a) When...

  13. 46 CFR 197.434 - Surface-supplied mixed-gas diving.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Surface-supplied mixed-gas diving. 197.434 Section 197... HEALTH STANDARDS GENERAL PROVISIONS Commercial Diving Operations Specific Diving Mode Procedures § 197.434 Surface-supplied mixed-gas diving. The diving supervisor shall insure that— (a) When...

  14. [Research advances in aerobic denitrifiers].

    PubMed

    Wang, Wei; Cai, Zu-cong; Zhong, Wen-hui; Wang, Guo-xiang

    2007-11-01

    This paper reviewed the varieties and characteristics of aerobic denitrifiers, their action mechanisms, and the factors affecting aerobic denitrification. Aerobic denitrifiers mainly include Pseudomonas, Alcaligenes, Paracoccus and Bacillus, which are either aerobic or facultative aerobic, and heterotrophic. They can denitrify under aerobic conditions, with the main product being N2O. They can also convert NH4+ -N to gas product. The nitrate reductase which catalyzes the denitrification is periplasmic nitrate reductase rather than membrane-bound nitrate reductase. Dissolved oxygen concentration and C/N ratio are the main factors affecting aerobic denitrification. The main methods for screening aerobic denitrifiers, such as intermittent aeration and selected culture, were also introduced. The research advances in the application of aerobic denitrifiers in aquaculture, waste water processing, and bio-degradation of organic pollutants, as well as the contributions of aerobic denitrifiers to soil nitrogen emission were summarized. PMID:18260473

  15. Meeting reproductive demands in a dynamic upwelling system: Foraging strategies of a pursuit-diving seabird, the marbled murrelet

    USGS Publications Warehouse

    Peery, M.Z.; Newman, S.H.; Storlazzi, C.D.; Beissinger, S.R.

    2009-01-01

    Seabirds maintain plasticity in their foraging behavior to cope with energy demands and foraging constraints that vary over the reproductive cycle, but behavioral studies comparing breeding and nonbreeding individuals are rare. Here we characterize how Marbled Murrelets (Brachyramphus marmoratus) adjust their foraging effort in response to changes in reproductive demands in an upwelling system in central California. We radio-marked 32 murrelets of known reproductive status (9 breeders, 12 potential breeders, and 11 nonbreeders) and estimated both foraging ranges and diving rates during the breeding season. Murrelets spent more time diving during upwelling than oceanographic relaxation, increased their foraging ranges as the duration of relaxation grew longer, and reduced their foraging ranges after transitions to upwelling. When not incubating, murrelets moved in a circadian pattern, spending nighttime hours resting near flyways used to reach nesting habitat and foraging during the daytime an average of 5.7 km (SD 6.7 km) from nighttime locations. Breeders foraged close to nesting habitat once they initiated nesting and nest attendance was at a maximum, and then resumed traveling longer distances following the completion of nesting. Nonbreeders had similar nighttime and daytime distributions and tended to be located farther from inland flyways. Breeders increased the amount of time they spent diving by 71-73% when they had an active nest by increasing the number of dives rather than by increasing the frequency of anaerobiosis. Thus, to meet reproductive demands during nesting, murrelets adopted a combined strategy of reducing energy expended commuting to foraging sites and increasing aerobic dive rates. ?? 2009 by The Cooper Ornithological Society. All rights reserved.

  16. Limiter

    DOEpatents

    Cohen, Samuel A.; Hosea, Joel C.; Timberlake, John R.

    1986-01-01

    A limiter with a specially contoured front face accommodates the various power scrape-off distances .lambda..sub.p, which depend on the parallel velocity, V.sub..parallel., of the impacting particles. The front face of the limiter (the plasma-side face) is flat with a central indentation. In addition, the limiter shape is cylindrically symmetric so that the limiter can be rotated for greater heat distribution.

  17. A forensic diving medicine examination of a highly publicised scuba diving fatality.

    PubMed

    Edmonds, Carl

    2012-12-01

    A high-profile diving death occurred in 2003 at the site of the wreck of the SS Yongala off the Queensland coast. The victim's buddy, her husband, was accused of her murder and found guilty of manslaughter in an Australian court. A detailed analysis of all the evidence concerning this fatality suggests alternative medical reasons for her death. The value of decompression computers in determining the diving details and of CT scans in clarifying autopsy findings is demonstrated. The victim was medically, physically and psychologically unfit to undertake the fatal dive. She was inexperienced and inadequately supervised. She was over-weighted and exposed for the first time to difficult currents. The analysis of the dive demonstrates how important it is to consider the interaction of all factors and to not make deductions from individual items of information. It also highlights the importance of early liaison between expert divers, technicians, diving clinicians and pathologists, if inappropriate conclusions are to be avoided. PMID:23258459

  18. Deadly diving? Physiological and behavioural management of decompression stress in diving mammals

    PubMed Central

    Hooker, S. K.; Fahlman, A.; Moore, M. J.; Aguilar de Soto, N.; Bernaldo de Quirós, Y.; Brubakk, A. O.; Costa, D. P.; Costidis, A. M.; Dennison, S.; Falke, K. J.; Fernandez, A.; Ferrigno, M.; Fitz-Clarke, J. R.; Garner, M. M.; Houser, D. S.; Jepson, P. D.; Ketten, D. R.; Kvadsheim, P. H.; Madsen, P. T.; Pollock, N. W.; Rotstein, D. S.; Rowles, T. K.; Simmons, S. E.; Van Bonn, W.; Weathersby, P. K.; Weise, M. J.; Williams, T. M.; Tyack, P. L.

    2012-01-01

    Decompression sickness (DCS; ‘the bends’) is a disease associated with gas uptake at pressure. The basic pathology and cause are relatively well known to human divers. Breath-hold diving marine mammals were thought to be relatively immune to DCS owing to multiple anatomical, physiological and behavioural adaptations that reduce nitrogen gas (N2) loading during dives. However, recent observations have shown that gas bubbles may form and tissue injury may occur in marine mammals under certain circumstances. Gas kinetic models based on measured time-depth profiles further suggest the potential occurrence of high blood and tissue N2 tensions. We review evidence for gas-bubble incidence in marine mammal tissues and discuss the theory behind gas loading and bubble formation. We suggest that diving mammals vary their physiological responses according to multiple stressors, and that the perspective on marine mammal diving physiology should change from simply minimizing N2 loading to management of the N2 load. This suggests several avenues for further study, ranging from the effects of gas bubbles at molecular, cellular and organ function levels, to comparative studies relating the presence/absence of gas bubbles to diving behaviour. Technological advances in imaging and remote instrumentation are likely to advance this field in coming years. PMID:22189402

  19. Diving dentistry: a review of the dental implications of scuba diving.

    PubMed

    Zadik, Y; Drucker, S

    2011-09-01

    In light of the overwhelming popularity of self-contained underwater breathing apparatus (SCUBA) diving, general dental practitioners should be prepared to address complications arising as a result of diving and to provide patients with accurate information. The aim of this article was to introduce the concepts of diving medicine and dentistry to the dentist, and to supply the dental practitioner with some diagnostic tools as well as treatment guidelines. The literature was reviewed to address diving barotrauma (pressure-induced injury related to an air space) to the head, face and oral regions, as well as scuba mouthpiece-related oral conditions. The relevant conditions for dentists who treat divers include diving-associated headache (migraine, tension-type headache), barosinusitis and barotitis-media (sinus and middle ear barotrauma, respectively), neuropathy, trigeminal (CN V) or facial (CN VII) nerve baroparesis (pressure-induced palsy), dental barotrauma (barometric-related tooth injury), barodontalgia (barometric-related dental pain), mouthpiece-associated herpes infection, pharyngeal gag reflex and temporomandibular joint disorder (dysfunction). For each condition, a theoretical description is followed by practical recommendations for the dental practitioner for the prevention and management of the condition. PMID:21884141

  20. Sudden infant death triggered by dive reflex.

    PubMed

    Matturri, L; Ottaviani, G; Lavezzi, A M

    2005-01-01

    The dive reflex is the reflex mechanism most frequently considered in the aetiopathogenesis of sudden infant death syndrome (SIDS). This seems to persist in human beings as an inheritance from diver birds and amphibians. It has been reported that washing the face with cold water or plunging into cold water can provoke cardiac deceleration through the intervention of the ambiguus and the vagal dorsal nuclei. This report describes a case of SIDS that offers a unique insight into the role of the dive reflex in determining a lethal outcome. Examination of the brainstem on serial sections revealed severe bilateral hypoplasia of the arcuate nucleus and gliosis of the other cardiorespiratory medullary nuclei. The coronary and cardiac conduction arteries presented early atherosclerotic lesions. The possible role of parental cigarette smoking in the pathogenesis of arcuate nucleus hypoplasia and early coronary atherosclerotic lesions is also discussed. PMID:15623488

  1. [Asthma and diving with a cylinder].

    PubMed

    Boutet, S; Salvia, P; Potiron, M

    1999-09-01

    Undersea diving is an activity that is practised more and more in holiday clubs. There is no precise legislation on the causes of unfitness of the amateur, in contrast to the professional diver, where the medical criteria are strict and controlled. When diving with a cylinder, on descent, the ventilatory load increases with increase of the ambient pressure and dynamic resistance in the airways increases. "As with an insufficient respiration on the surface, a healthy subject when diving has a ventilatory ability that is drastically reduced". Moreover with cylinder ventilation, the diver has available a reserve of gas under pressure from which he inspires with the aid of a breathing apparatus (regulator): he breathes dry gas that is dried before compression in the reservoirs, chilled by the relief valve on leaving the reservoir. This inhalation of cold, dry air associated with a hyperventilation during the descent produces ideal conditions to trigger exercise induced asthma. All subjects who present a bronchial hyperreactivity have the risk when diving with a cylinder of triggering a bronchospasm that is identical with that of a sporting asthmatic. During surfacing: the re-surfacing diver runs the risk of an accident of pulmonary suppression if he does not expire sufficiently during his return to the surface: the mass of intrapulmonary air of the resurfacer dilates and the excess of volume is exhaled by the diver: a volume of air of 5 l at 10 m depth corresponds to a volume of 10 l on the surface. Therefore the airways must remain free: an obstruction of the peripheral airways associated with an urgent re-surfacing produces a very rapid thoracic dilation which is responsible for pulmonary barotrauma (pulmonary barotrauma is frequently lethal with 30% of accidental deaths). PMID:10524270

  2. Sphenoid sinus barotrauma after scuba diving.

    PubMed

    Jeong, Jin Hyeok; Kim, Kuk; Cho, Seok Hyun; Kim, Kyung Rae

    2012-01-01

    We report the case of an 18-year-old male patient operated on for sphenoid sinus barotrauma after scuba diving. The patient attended our emergency department because of intractable headache but did not improve with conservative treatment. After computed tomography and magnetic resonance imaging examination, he was diagnosed with sphenoid sinusitis that extended to the nasal septum. He therefore underwent surgery for sinus ventilation and abscess drainage. PMID:22133966

  3. Effect of scuba-diving on optic nerve and sheath diameters

    PubMed Central

    Mehrpour, Masoud; Shams-Hosseini, Narges Sadat; Rezaali, Saeed

    2014-01-01

    Background: There is not any data available about the effect of high bar pressure condition on intracranial pressure. In this study, the effect of diving on the optic nerve and sheath diameters as non-invasive markers of intracranial pressure has been investigated. Methods: Twenty professional male divers from twenty one volunteers were chosen for this cross-sectional study. Only one person who had a history of barotraumas was excluded. Each diver then completed a questionnaire on demographic data, medical and diving history. Nineteen other volunteers were selected to represent a control group. A 10-MHz linear ultrasonic probe was used to measure the optic nerve sheath diameters of both eyes in closed and supine position and its relationship with diving history of divers was determined. Results: It was found that divers have a higher mean optic nerve sheath diameter compared to the normal population as previously reported by other studies. The mean diameter of the left and right optic nerve sheaths were 6.4±0.7, 6.5±0.9 mm respectively and a significant relationship between optic nerve sheath diameter and diving history was found. Conclusion: Results showed that divers have a higher optic nerve diameter than the general population. However, our result cannot yet be considered as a marker of intracranial pressure in divers as it was conducted on an limited number of subjects and so a bigger study should be undertaken for this purpose. PMID:25664290

  4. Diving pattern and work schedule of construction well divers in Taiwan.

    PubMed

    Huang, K L; Lee, H C; Huang, G B; Lin, T F; Niu, K C; Liou, S H; Lin, Y C

    1998-01-01

    Construction well divers in Taiwan reportedly suffer a high prevalence of dysbaric osteonecrosis. We studied five divers working at the same construction site. We recorded their diving methods, diving depths, bottom times, work patterns, water temperatures, and heart rates. We also monitored gas bubbles in the subclavian vein in selected dives. A crude but effective hot-water system protected divers against hypothermia and allowed them to work in 24 degrees-27 degrees C water. Divers worked approximately 6.6 h a day and progressed approximately 3.0 m a day while excavating an average of 148 buckets of sand and rock each weighing 49.5 kg. The divers sustained a heart rate increase of 49%. Sixty percent of their equivalent single dive bottom times exceeded the U.S. Navy's no-decompression limits. Two cases of venous bubbles were detected, and one of these divers showed symptoms of decompression sickness. The prolonged bottom time and lack of a decompression schedule probably contributed to a risk of decompression sickness and dysbaric osteonecrosis. PMID:9670435

  5. Enriched Air Nitrox Breathing Reduces Venous Gas Bubbles after Simulated SCUBA Diving: A Double-Blind Cross-Over Randomized Trial

    PubMed Central

    Souday, Vincent; Koning, Nick J.; Perez, Bruno; Grelon, Fabien; Mercat, Alain; Boer, Christa; Seegers, Valérie; Radermacher, Peter; Asfar, Pierre

    2016-01-01

    Objective To test the hypothesis whether enriched air nitrox (EAN) breathing during simulated diving reduces decompression stress when compared to compressed air breathing as assessed by intravascular bubble formation after decompression. Methods Human volunteers underwent a first simulated dive breathing compressed air to include subjects prone to post-decompression venous gas bubbling. Twelve subjects prone to bubbling underwent a double-blind, randomized, cross-over trial including one simulated dive breathing compressed air, and one dive breathing EAN (36% O2) in a hyperbaric chamber, with identical diving profiles (28 msw for 55 minutes). Intravascular bubble formation was assessed after decompression using pulmonary artery pulsed Doppler. Results Twelve subjects showing high bubble production were included for the cross-over trial, and all completed the experimental protocol. In the randomized protocol, EAN significantly reduced the bubble score at all time points (cumulative bubble scores: 1 [0–3.5] vs. 8 [4.5–10]; P < 0.001). Three decompression incidents, all presenting as cutaneous itching, occurred in the air versus zero in the EAN group (P = 0.217). Weak correlations were observed between bubble scores and age or body mass index, respectively. Conclusion EAN breathing markedly reduces venous gas bubble emboli after decompression in volunteers selected for susceptibility for intravascular bubble formation. When using similar diving profiles and avoiding oxygen toxicity limits, EAN increases safety of diving as compared to compressed air breathing. Trial Registration ISRCTN 31681480 PMID:27163253

  6. Methods to determine aerobic endurance.

    PubMed

    Bosquet, Laurent; Léger, Luc; Legros, Patrick

    2002-01-01

    Physiological testing of elite athletes requires the correct identification and assessment of sports-specific underlying factors. It is now recognised that performance in long-distance events is determined by maximal oxygen uptake (V(2 max)), energy cost of exercise and the maximal fractional utilisation of V(2 max) in any realised performance or as a corollary a set percentage of V(2 max) that could be endured as long as possible. This later ability is defined as endurance, and more precisely aerobic endurance, since V(2 max) sets the upper limit of aerobic pathway. It should be distinguished from endurance ability or endurance performance, which are synonymous with performance in long-distance events. The present review examines methods available in the literature to assess aerobic endurance. They are numerous and can be classified into two categories, namely direct and indirect methods. Direct methods bring together all indices that allow either a complete or a partial representation of the power-duration relationship, while indirect methods revolve around the determination of the so-called anaerobic threshold (AT). With regard to direct methods, performance in a series of tests provides a more complete and presumably more valid description of the power-duration relationship than performance in a single test, even if both approaches are well correlated with each other. However, the question remains open to determine which systems model should be employed among the several available in the literature, and how to use them in the prescription of training intensities. As for indirect methods, there is quantitative accumulation of data supporting the utilisation of the AT to assess aerobic endurance and to prescribe training intensities. However, it appears that: there is no unique intensity corresponding to the AT, since criteria available in the literature provide inconsistent results; and the non-invasive determination of the AT using ventilatory and heart rate

  7. 46 CFR 197.434 - Surface-supplied mixed-gas diving.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... bell is used for dives deeper than 220 fsw or when the dive involves in-water decompression times... physically confining space; (d) A closed bell is used for dives at depths greater than 300 fsw, except...

  8. 46 CFR 197.434 - Surface-supplied mixed-gas diving.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... bell is used for dives deeper than 220 fsw or when the dive involves in-water decompression times... physically confining space; (d) A closed bell is used for dives at depths greater than 300 fsw, except...

  9. 46 CFR 197.434 - Surface-supplied mixed-gas diving.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... bell is used for dives deeper than 220 fsw or when the dive involves in-water decompression times... physically confining space; (d) A closed bell is used for dives at depths greater than 300 fsw, except...

  10. Dive behaviour can predict metabolic expenditure in Steller sea lions.

    PubMed

    Goundie, Elizabeth T; Rosen, David A S; Trites, Andrew W

    2015-01-01

    Quantification of costs associated with foraging contributes to understanding the energetic impact that changes in prey availability have on the energy balance of an animal and the fitness of populations. However, estimating the costs of foraging is difficult for breath-hold divers, such as Steller sea lions, that feed underwater. We developed models parameterized with data from free-diving captive Steller sea lions to estimate the costs incurred by wild animals while foraging. We measured diving metabolic rate of trained sea lions performing four types of dives to 10 and 40 m in the open ocean and estimated the separate costs of different dive components: surface time; bottom time; and transiting to and from depth. We found that the sea lions' diving metabolic rates were higher while transiting (20.5 ± 13.0 ml O2 min(-1) kg(-1)) than while swimming at depth (13.5 ± 4.1 ml O2 min(-1) kg(-1)), and both were higher than metabolism at the surface (9.2 ± 1.6 ml O2 min(-1) kg(-1)). These values were incorporated into an energetic model that accurately predicted oxygen consumption for dives only (within 9.5%) and dive cycles (within 7.7%), although it consistently overestimated costs by 5.9% for dives and 21.8% for dive cycles. Differences in the costs of individual components of dives also explained differences in the efficiency of different dive strategies. Single dives were energetically less costly than bout dives; however, sea lions were more efficient at replenishing oxygen stores after bout dives and could therefore spend a greater portion of their time foraging than when undertaking single dives. The metabolic rates we measured for the different behavioural components of diving can be applied to time-depth recordings from wild Steller sea lions to estimate the energy expended while foraging. In turn, this can be used to understand how changes in prey availability affect energy balance and the health of individuals in

  11. Dive behaviour can predict metabolic expenditure in Steller sea lions

    PubMed Central

    Goundie, Elizabeth T.; Rosen, David A. S.; Trites, Andrew W.

    2015-01-01

    Quantification of costs associated with foraging contributes to understanding the energetic impact that changes in prey availability have on the energy balance of an animal and the fitness of populations. However, estimating the costs of foraging is difficult for breath-hold divers, such as Steller sea lions, that feed underwater. We developed models parameterized with data from free-diving captive Steller sea lions to estimate the costs incurred by wild animals while foraging. We measured diving metabolic rate of trained sea lions performing four types of dives to 10 and 40 m in the open ocean and estimated the separate costs of different dive components: surface time; bottom time; and transiting to and from depth. We found that the sea lions' diving metabolic rates were higher while transiting (20.5 ± 13.0 ml O2 min−1 kg−1) than while swimming at depth (13.5 ± 4.1 ml O2 min−1 kg−1), and both were higher than metabolism at the surface (9.2 ± 1.6 ml O2 min−1 kg−1). These values were incorporated into an energetic model that accurately predicted oxygen consumption for dives only (within 9.5%) and dive cycles (within 7.7%), although it consistently overestimated costs by 5.9% for dives and 21.8% for dive cycles. Differences in the costs of individual components of dives also explained differences in the efficiency of different dive strategies. Single dives were energetically less costly than bout dives; however, sea lions were more efficient at replenishing oxygen stores after bout dives and could therefore spend a greater portion of their time foraging than when undertaking single dives. The metabolic rates we measured for the different behavioural components of diving can be applied to time–depth recordings from wild Steller sea lions to estimate the energy expended while foraging. In turn, this can be used to understand how changes in prey availability affect energy balance and the health of individuals in

  12. SCUBA medicine: a first-responder's guide to diving injuries.

    PubMed

    Salahuddin, Moin; James, Laurie A; Bass, Evan Stuart

    2011-01-01

    Self-contained underwater breathing apparatus (SCUBA) diving is an ever-growing sport, and despite a myriad of technological advances to improve safety, it remains dangerous. Providers of medical care for SCUBA divers must have an understanding of diving physiology and potential medical problems that can occur. SCUBA diving also can take participants to remote areas, so being properly prepared for potential emergencies can make a significant difference. The following is a review of diving physiology and the medical problems that can occur in SCUBA divers, along with some suggestions as to how to prepare for a SCUBA excursion. PMID:21623301

  13. Repetitive breath-hold diving causes serious brain injury.

    PubMed

    Tamaki, Hideki; Kohshi, Kiyotaka; Sajima, Shuichi; Takeyama, Junichiro; Nakamura, Takashi; Ando, Hideo; Ishitake, Tatsuya

    2010-01-01

    We report on a Japanese male professional breath-hold diver (Ama) who developed neurological disorders during repetitive dives to 22 meters of sea water. Each diving duration and surface interval were 40-80 seconds and 20-30 seconds, respectively. He suffered from sensory numbness of the right cheek, hand and foot, and double vision after more than two hours of consecutive dives. Magnetic resonance images of his brain showed multiple cerebral infarcts, and one of the lesions was situated in the brainstem. There is a possibility that repetitive deep breath-hold dives with short surface intervals can induce fatal accidents for divers. PMID:20369648

  14. Future synergism in diving accident management: The Singapore model.

    PubMed

    Chong, Si Jack; Liang, Weihao; Kim, Soo Jang; Kang, Wee Lee

    2010-03-01

    The popularity of diving as a leisure activity has been an increasing trend in recent years. With the rise of this sport inevitably comes increasing numbers and risk of diving-related injuries and demand for professional medical treatment of such injuries. Concurrently, with hyperbaric oxygen therapy (HBOT) being more readily available, new applications for HBOT have been proven for the treatment of various medical conditions. In Singapore, diving and hyperbaric medicine was largely a military medicine specialty and its practice confined to the Singapore Armed Forces for many years. The new Hyperbaric and Diving Medicine Centre set up in Singapore General Hospital (SGH) offers an excellent opportunity for collaboration between the Singapore Navy Medical Service (NMS) and SGH. This combines the expertise in the field of diving and hyperbaric medicine that NMS provides, with the resources and specialized services available at SGH. This collaboration was officially formalized by the recent signing of a Memorandum of Understanding between the two organisations. The partnership will allow both organisations to leverage on each other's strengths and enhance the development of research and training capabilities. This collaboration will also be an important step towards formal recognition and accreditation of diving and hyperbaric medicine as a medical subspecialty in the foreseeable future, thus helping to develop and promote diving and hyperbaric medicine in Singapore. This synergistic approach in diving accident management will also promote and establish Singapore as a leader in the field of diving and hyperbaric medicine in the region. PMID:23111838

  15. Diving into the Ice Bucket Challenge: Intraparenchymal Hemorrhage and the Mammalian Diving Reflex.

    PubMed

    McKee, Kathleen; Nelson, Sarah; Batra, Ayush; Klein, Joshua P; Henderson, Galen V

    2015-07-01

    Triggered by facial exposure to cold water and apnea, the mammalian diving reflex consists of bradycardia and peripheral arteriolar vasoconstriction leading to an increase in central arterial pressure. It has been previously associated with ischemic stroke but not definitively with intracerebral hemorrhage. We present a case of intracerebral hemorrhage occurring in a woman with poorly controlled hypertension following her participation in the amyotrophic lateral sclerosis fund-raising "Ice Bucket Challenge," in which ice-cold water was poured on her head. We suspect that facial exposure to ice-cold water triggered the diving reflex, causing a hypertensive surge and ultimately the intracerebral hemorrhage. PMID:26288676

  16. Brain magnetic resonance imaging, aerobic power, and metabolic parameters among 30 asymptomatic scuba divers.

    PubMed

    Tripodi, D; Dupas, B; Potiron, M; Louvet, S; Geraut, C

    2004-11-01

    The aim of the study was to evaluate the presence of cerebral lesions in asymptomatic scuba divers and explain the causes of them: potential risk factors associating cardiovascular risk factors, low aerobic capacity, or characteristics of diving (maximum depth, ascent rate). Experienced scuba divers, over 40 years of age, without any decompression sickness (DCS) history were included. We studied 30 scuba divers (instructors) without any clinical symptoms. For all of them, we carried out a clinical examination with fatty body mass determination and we questioned them about their diving habits. A brain Magnetic Resonance imaging (MRI), an assessment of maximal oxygen uptake, glycemia, triglyceridemia, and cholesterolemia were systematically carried out. Cerebral spots of high intensity were found at 33 % in the scuba diving group and 30 % in the control group. In the diving group, abnormalities were related to unsafe scuba-diving or metabolic abnormalities. In our study, we did not find a significant relationship between the lesions of the central nervous system, and the age, depth of the dives, number of dives, and ergometric performances (maximal oxygen uptake, V.O (2max), serum level of blood lactate). Nevertheless, we found a significant relationship between the lesions of the central nervous system and ascent rate faster than 10 meters per minute (r = 0.57; p = 0.003) or presence of high level of cholesterolemia (r = 0.6; p = 0.001). We found concordant results using the Cochran's Test: meaningful link between the number of brain lesions and the speed of decompression (Uexp = 14 < Utable = 43; alpha = 0.05, p < 0.01). We concluded that hyperintensities can be explained by preformed nitrogen gas microbubbles and particularly in presence of cholesterol, when the ascent rate is up to 10 meters per minute. So, it was remarkable to note that asymptomatic patients practicing scuba diving either professionally or recreationally, presented lesions of the central nervous

  17. Diving through the thermal window: implications for a warming world

    PubMed Central

    Campbell, Hamish A.; Dwyer, Ross G.; Gordos, Matthew; Franklin, Craig E.

    2010-01-01

    Population decline and a shift in the geographical distribution of some ectothermic animals have been attributed to climatic warming. Here, we show that rises in water temperature of a few degrees, while within the thermal window for locomotor performance, may be detrimental to diving behaviour in air-breathing ectotherms (turtles, crocodilians, marine iguanas, amphibians, snakes and lizards). Submergence times and internal and external body temperature were remotely recorded from freshwater crocodiles (Crocodylus johnstoni) while they free-ranged throughout their natural habitat in summer and winter. During summer, the crocodiles' mean body temperature was 5.2 ± 0.1°C higher than in winter and the largest proportion of total dive time was composed of dive durations approximately 15 min less than in winter. Diving beyond 40 min during summer required the crocodiles to exponentially increase the time they spent on the surface after the dive, presumably to clear anaerobic debt. The relationship was not as significant in winter, even though a greater proportion of dives were of a longer duration, suggesting that diving lactate threshold (DLT) was reduced in summer compared with winter. Additional evidence for a reduced DLT in summer was derived from the stronger influence body mass exerted upon dive duration, compared to winter. The results demonstrate that the higher summer body temperature increased oxygen demand during the dive, implying that thermal acclimatization of the diving metabolic rate was inadequate. If the study findings are common among air-breathing diving ectotherms, then long-term warming of the aquatic environment may be detrimental to behavioural function and survivorship. PMID:20610433

  18. Scanning sonar of rolling porpoises during prey capture dives.

    PubMed

    Akamatsu, T; Wang, D; Wang, K; Li, S; Dong, S

    2010-01-01

    Dolphins and porpoises have excellent biosonar ability, which they use for navigation, ranging and foraging. However, the role of biosonar in free-ranging small cetaceans has not been fully investigated. The biosonar behaviour and body movements of 15 free-ranging finless porpoises (Neophocaena phocaenoides) were observed using electronic tags attached to the animals. The porpoises often rotated their bodies more than 60 deg., on average, around the body axis in a dive bout. This behaviour occupied 31% of the dive duration during 186 h of effective observation time. Rolling dives were associated with extensive searching effort, and 23% of the rolling dive time was phonated, almost twice the phonation ratio of upright dives. Porpoises used short inter-click interval sonar 4.3 times more frequently during rolling dives than during upright dives. Sudden speed drops, which indicated that an individual turned around, occurred 4.5 times more frequently during rolling dives than during upright dives. Together, these data suggest that the porpoises searched extensively for targets and rolled their bodies to enlarge the search area by changing the narrow beam axis of the biosonar. Once a possible target was detected, porpoises frequently produced short-range sonar sounds. Continuous searching for prey and frequent capture trials appeared to occur during rolling dives of finless porpoises. In contrast, head movements ranging +/-2 cm, which can also change the beam axis, were regularly observed during both dives. Head movements might assist in instant assessment of the arbitrary direction by changing the beam axis rather than prey searching and pursuit. PMID:20008371

  19. Yet More Visualized JAMSTEC Cruise and Dive Information

    NASA Astrophysics Data System (ADS)

    Tomiyama, T.; Hase, H.; Fukuda, K.; Saito, H.; Kayo, M.; Matsuda, S.; Azuma, S.

    2014-12-01

    Every year, JAMSTEC performs about a hundred of research cruises and numerous dive surveys using its research vessels and submersibles. JAMSTEC provides data and samples obtained during these cruises and dives to international users through a series of data sites on the Internet. The "DARWIN (http://www.godac.jamstec.go.jp/darwin/e)" data site disseminates cruise and dive information. On DARWIN, users can search interested cruises and dives with a combination search form or an interactive tree menu, and find lists of observation data as well as links to surrounding databases. Document catalog, physical sample databases, and visual archive of dive surveys (e. g. in http://www.godac.jamstec.go.jp/jmedia/portal/e) are directly accessible from the lists. In 2014, DARWIN experienced an update, which was arranged mainly for enabling on-demand data visualization. Using login users' functions, users can put listed data items into the virtual basket and then trim, plot and download the data. The visualization tools help users to quickly grasp the quality and characteristics of observation data. Meanwhile, JAMSTEC launched a new data site named "JDIVES (http://www.godac.jamstec.go.jp/jdives/e)" to visualize data and sample information obtained by dive surveys. JDIVES shows tracks of dive surveys on the "Google Earth Plugin" and diagrams of deep-sea environmental data such as temperature, salinity, and depth. Submersible camera images and links to associated databases are placed along the dive tracks. The JDVIES interface enables users to perform so-called virtual dive surveys, which can help users to understand local geometries of dive spots and geological settings of associated data and samples. It is not easy for individual researchers to organize a huge amount of information recovered from each cruise and dive. The improved visibility and accessibility of JAMSTEC databases are advantageous not only for second-hand users, but also for on-board researchers themselves.

  20. Effect of recreational diving on Patagonian rocky reefs.

    PubMed

    Bravo, Gonzalo; Márquez, Federico; Marzinelli, Ezequiel M; Mendez, María M; Bigatti, Gregorio

    2015-03-01

    Tourism has grown considerably in the last decades, promoting activities such as recreational SCUBA diving that may affect marine benthic communities. In Puerto Madryn, Patagonia Argentina, sub-aquatic tourism areas (STA) receive about 7,000 divers per year. Diving is concentrated on a few small rocky reefs and 50% of the dives occur in summer. In this work, we evaluated the effect of recreational diving activities on benthic communities and determined whether diving causes a press (long-term) or a pulse (short-term) response. We quantified the percentage cover of benthic organisms and compared benthic assemblage structure and composition between two sites with contrasting usage by divers, 'highly disturbed' and 'moderately disturbed' sites, and two 'control' sites with similar physical characteristics but no diving activity, twice before and after the diving peak in summer. We found differences in benthic assemblage structure (identity and relative abundance of taxa) and composition (identity only) among diving sites and controls. These differences were consistent before and after the peak of diving in summer, suggesting that recreational diving may produce a press impact on overall benthic assemblage structure and composition in these STA. At the moderately disturbed site, however, covers of specific taxa, such as some key habitat-forming or highly abundant species, usually differed from those in controls only immediately after summer, after which they begun to resemble controls, suggesting a pulse impact. Thus, STA in Golfo Nuevo seem to respond differently to disturbances of diving depending on the usage of the sites. This information is necessary to develop sound management strategies in order to preserve local biodiversity. PMID:25577688

  1. Dance--Aerobic and Anaerobic.

    ERIC Educational Resources Information Center

    Cohen, Arlette

    1984-01-01

    This article defines and explains aerobic exercise and its effects on the cardiovascular system. Various studies on dancers are cited indicating that dance is an anaerobic activity with some small degree of aerobic benefit. (DF)

  2. Development of Dive Capacity in Northern Elephant Seals (Mirounga angustirostris): Reduced Body Reserves at Weaning Are Associated with Elevated Body Oxygen Stores during the Postweaning Fast.

    PubMed

    Somo, Derek A; Ensminger, David C; Sharick, Jeffrey T; Kanatous, Shane B; Crocker, Daniel E

    2015-01-01

    Developmental increases in dive capacity have been reported in numerous species of air-breathing marine vertebrates. Previous studies in juvenile phocid seals suggest that increases in physiological dive capacity during the postweaning fast (PWF) are critical to support independent aquatic foraging. Although there is a strong relationship between size at weaning and PWF duration and body reserves at weaning vary considerably, few studies have considered whether such variation in body reserve magnitude promotes phenotypic modulation of dive capacity development during the PWF. Phenotypic modulation, a form of developmental plasticity in which rates and degrees of expression of the developmental program are modulated by environmental factors, may enhance diving capacity in weanlings with reduced PWF durations due to smaller body reserves at weaning if reduced body reserves promote accelerated development of dive capacity. We longitudinally measured changes in blood and muscle oxygen stores and muscle metabolic enzymes over the first 8 wk of the PWF in northern elephant seals and determined whether rates of change in these parameters varied with body reserves at weaning. We assessed whether erythropoietin (EPO), thyroid hormones, serum nonesterified fatty acid levels, and iron status influenced blood and muscle oxygen store development or were influenced by body reserves at weaning. Although mass-specific plasma volume and blood volume were relatively stable across the fast, both were elevated in animals with reduced body reserves. Surprisingly, hemoglobin and mean corpuscular hemoglobin concentrations declined over the PWF while hematocrit remained stable, and these variables were not associated with body reserves or EPO. Swimming muscle myoglobin and serum iron levels increased rapidly early in the PWF and were not related to body reserves. Patterns in maximal activities of muscle enzymes suggested a decline in total aerobic and anaerobic metabolic capacity over the

  3. Joint position statement on persistent foramen ovale (PFO) and diving. South Pacific Underwater Medicine Society (SPUMS) and the United Kingdom Sports Diving Medical Committee (UKSDMC).

    PubMed

    Smart, David; Mitchell, Simon; Wilmshurst, Peter; Turner, Mark; Banham, Neil

    2015-06-01

    This consensus statement is the result of a workshop at the SPUMS Annual Scientific Meeting 2014 with representatives of the UK Sports Diving Medical Committee (UKSDMC) present, and subsequent discussions including the entire UKSDMC. Right-to-left shunt across a persistent or patent foramen ovale (PFO) is a risk factor for some types of decompression illness. It was agreed that routine screening for PFO is not currently justifiable, but certain high risk sub-groups can be identified. Divers with a history of cerebral, spinal, inner-ear or cutaneous decompression illness, migraine with aura, a family history of PFO or atrial septal defect and those with other forms of congenital heart disease are considered to be at higher risk. For these individuals, screening should be considered. If screening is undertaken it should be by bubble contrast transthoracic echocardiography with provocative manoeuvres, including Valsalva release and sniffing. Appropriate quality control is important. If a shunt is present, advice should be provided by an experienced diving physician taking into account the clinical context and the size of shunt. Reduction in gas load by limiting depth, repetitive dives and avoiding lifting and straining may all be appropriate. Divers may consider transcatheter device closure of the PFO in order to return to normal diving. If transcatheter PFO closure is undertaken, repeat bubble contrast echocardiography must be performed to confirm adequate reduction or abolition of the right-to-left shunt, and the diver should have stopped taking potent anti-platelet therapy (aspirin is acceptable). PMID:26165538

  4. 29 CFR 1926.1081 - Pre-dive procedures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Pre-dive procedures. 1926.1081 Section 1926.1081 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving General Operations Procedures §...

  5. 29 CFR 1926.1081 - Pre-dive procedures.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 8 2011-07-01 2011-07-01 false Pre-dive procedures. 1926.1081 Section 1926.1081 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving General Operations Procedures §...

  6. 29 CFR 1926.1083 - Post-dive procedures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Post-dive procedures. 1926.1083 Section 1926.1083 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving General Operations Procedures §...

  7. 29 CFR 1926.1082 - Procedures during dive.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 8 2011-07-01 2011-07-01 false Procedures during dive. 1926.1082 Section 1926.1082 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving General Operations Procedures §...

  8. 29 CFR 1926.1076 - Qualifications of dive team.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Qualifications of dive team. 1926.1076 Section 1926.1076 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving Personnel...

  9. 29 CFR 1926.1083 - Post-dive procedures.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 8 2011-07-01 2011-07-01 false Post-dive procedures. 1926.1083 Section 1926.1083 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving General Operations Procedures §...

  10. 29 CFR 1926.1076 - Qualifications of dive team.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 8 2011-07-01 2011-07-01 false Qualifications of dive team. 1926.1076 Section 1926.1076 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving Personnel...

  11. Are the Risks of Sport Scuba Diving Being Underestimated?

    ERIC Educational Resources Information Center

    Roos, Robert

    1989-01-01

    A lawsuit has challenged the safety of the tables widely used in scuba diving. Other concerns also have emerged: A condition known as patent foramen ovale may increase the risk of decompression sickness, and studies are raising questions about the long-term effects of diving. (Author/JD)

  12. 29 CFR 1926.1082 - Procedures during dive.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Procedures during dive. 1926.1082 Section 1926.1082 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving General Operations Procedures §...

  13. 29 CFR 1926.1085 - Surface-supplied air diving.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 8 2012-07-01 2012-07-01 false Surface-supplied air diving. 1926.1085 Section 1926.1085 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION... Procedures § 1926.1085 Surface-supplied air diving. Note: The requirements applicable to construction...

  14. 29 CFR 1926.1085 - Surface-supplied air diving.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 8 2013-07-01 2013-07-01 false Surface-supplied air diving. 1926.1085 Section 1926.1085 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION... Procedures § 1926.1085 Surface-supplied air diving. Note: The requirements applicable to construction...

  15. Fatal diving accidents in western Norway 1983-2007.

    PubMed

    Ramnefjell, M P; Morild, I; Mørk, S J; Lilleng, P K

    2012-11-30

    Despite efforts to reduce their number, fatal diving accidents still occur. The circumstances and post-mortem findings in 40 fatal diving accidents in western Norway from 1983 through 2007 were investigated. Diving experience, medical history and toxicology reports were retrieved. The material consisted of recreational divers, professional saturation divers and professional divers without experience with saturation. In 33 cases the diving equipment was examined as part of the forensic investigation. In 27 cases defects in the diving equipment were found. For six divers such defects were responsible for the fatal accidents. Eighteen divers died on the surface or less than 10 m below surface. Five divers reached below 100 msw, and two of them died at this depth. The fatalities were not season-dependent. However, wave-height and strength of currents were influential factors in some cases. Twelve divers were diving alone. Twenty divers had one buddy, 9 of these divers were alone at the time of death. The cause of death was drowning in 31 out of 40 divers; one of them had a high blood-ethanol concentration, in two other divers ethanol was found in the urine, indicating previous ethanol consumption. Nine divers died from sudden decompression, pulmonary barotraumas, underwater trauma and natural causes. The study shows that most of the fatal diving accidents could be avoided if adequate diving safety procedures had been followed. PMID:22981212

  16. 29 CFR 1926.1082 - Procedures during dive.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 8 2014-07-01 2014-07-01 false Procedures during dive. 1926.1082 Section 1926.1082 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving General Operations Procedures §...

  17. 29 CFR 1926.1076 - Qualifications of dive team.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 8 2014-07-01 2014-07-01 false Qualifications of dive team. 1926.1076 Section 1926.1076 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving Personnel...

  18. 29 CFR 1926.1082 - Procedures during dive.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 8 2012-07-01 2012-07-01 false Procedures during dive. 1926.1082 Section 1926.1082 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving General Operations Procedures §...

  19. 29 CFR 1926.1076 - Qualifications of dive team.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 8 2012-07-01 2012-07-01 false Qualifications of dive team. 1926.1076 Section 1926.1076 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving Personnel...

  20. 29 CFR 1926.1081 - Pre-dive procedures.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 8 2012-07-01 2012-07-01 false Pre-dive procedures. 1926.1081 Section 1926.1081 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving General Operations Procedures §...

  1. 29 CFR 1926.1076 - Qualifications of dive team.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 8 2013-07-01 2013-07-01 false Qualifications of dive team. 1926.1076 Section 1926.1076 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving Personnel...

  2. 29 CFR 1926.1081 - Pre-dive procedures.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 8 2013-07-01 2013-07-01 false Pre-dive procedures. 1926.1081 Section 1926.1081 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving General Operations Procedures §...

  3. 29 CFR 1926.1082 - Procedures during dive.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 8 2013-07-01 2013-07-01 false Procedures during dive. 1926.1082 Section 1926.1082 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving General Operations Procedures §...

  4. 29 CFR 1926.1081 - Pre-dive procedures.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 8 2014-07-01 2014-07-01 false Pre-dive procedures. 1926.1081 Section 1926.1081 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving General Operations Procedures §...

  5. 29 CFR 1910.421 - Pre-dive procedures.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... transportation; and (5) The nearest U.S. Coast Guard Rescue Coordination Center. (c) First aid supplies. (1) A first aid kit appropriate for the diving operation and approved by a physician shall be available at the dive location. (2) When used in a decompression chamber or bell, the first aid kit shall be...

  6. 29 CFR 1910.421 - Pre-dive procedures.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... transportation; and (5) The nearest U.S. Coast Guard Rescue Coordination Center. (c) First aid supplies. (1) A first aid kit appropriate for the diving operation and approved by a physician shall be available at the dive location. (2) When used in a decompression chamber or bell, the first aid kit shall be...

  7. Diving bradycardia: a mechanism of defence against hypoxic damage.

    PubMed

    Alboni, Paolo; Alboni, Marco; Gianfranchi, Lorella

    2011-06-01

    A feature of all air-breathing vertebrates, diving bradycardia is triggered by apnoea and accentuated by immersion of the face or whole body in cold water. Very little is known about the afferents of diving bradycardia, whereas the efferent part of the reflex circuit is constituted by the cardiac vagal fibres. Diving bradycardia is associated with vasoconstriction of selected vascular beds and a reduction in cardiac output. The diving response appears to be more pronounced in mammals than in birds. In humans, the bradycardic response to diving varies greatly from person to person; the reduction in heart rate generally ranges from 15 to 40%, but a small proportion of healthy individuals can develop bradycardia below 20 beats/min. During prolonged dives, bradycardia becomes more pronounced because of activation of the peripheral chemoreceptors by a reduction in the arterial partial pressure of oxygen (O2), responsible for slowing of heart rate. The vasoconstriction is associated with a redistribution of the blood flow, which saves O2 for the O2-sensitive organs, such as the heart and brain. The results of several investigations carried out both in animals and in humans show that the diving response has an O2-conserving effect, both during exercise and at rest, thus lengthening the time to the onset of serious hypoxic damage. The diving response can therefore be regarded as an important defence mechanism for the organism. PMID:21330930

  8. Recent modifications to the investigation of diving related deaths.

    PubMed

    Edmonds, Carl; Caruso, James

    2014-03-01

    The investigation of deaths that involve diving using a compressed breathing gas (SCUBA diving) is a specialized area of forensic pathology. Diving related deaths occur more frequently in certain jurisdictions, but any medical examiner or coroner's office may be faced with performing this type of investigation. In order to arrive at the correct conclusion regarding the cause and manner of death, forensic pathologists and investigators need to have a basic understanding of diving physiology, and should also utilize more recently developed technology and ancillary techniques. In the majority of diving related deaths, the cause of death is drowning, but this more often represents a final common pathway due to a water environment. The chain of events leading to the death is just as important to elucidate if similar deaths are to be minimized in the future. Re-enactment of accident scenarios, interrogation of dive computers, postmortem radiographic imaging, and slight alterations in autopsy technique may allow some of these diving related deaths to the better characterized. The amount and location of gas present in the body at the time of autopsy may be very meaningful or may simply represent a postmortem artifact. Medical examiners, coroners, and forensic investigators should consider employing select ancillary techniques to more thoroughly investigate the factors contributing a death associated with SCUBA diving. PMID:24166195

  9. Diving: what to tell the patient with asthma and why?

    PubMed

    Krieger, B P

    2001-01-01

    Until a decade ago, divers with asthma were uniformly barred from diving with compressed air. This prohibition was based more on theoretical concerns for barotrauma than on actual data. Follow-up studies, although retrospective, do not support a ban on recreational or commercial diving for divers with stable asthma. These studies have noted that, despite the prohibition on diving, many divers with asthma have logged multiple dives without negative consequences. When those who have suffered diving-related barotrauma have undergone physiologic testing, measurements of small airways dysfunction (maximal mid-expiratory flow rates) have been lower than measurements for comparable divers who have never suffered diving accidents. Follow-up studies with long-term commercial divers have shown that a small percentage of individuals who have sufferred diving-related barotrauma also develop abnormal maximal mid-expiratory flow rates and even some airway hyperreactivity. These latter findings correlate with the changes that occur in chronic asthmatic patients, especially those who are not well treated. The decision as to whether an asthmatic patient should be allowed to dive rests on the individual's physiologic function, maturity, and insight into the consequences of poorly managed airway inflammation and bronchospasm. PMID:11140404

  10. Swimming & Diving: Special Olympics Sports Skills Instructional Program.

    ERIC Educational Resources Information Center

    Joseph P. Kennedy, Jr. Foundation, Washington, DC.

    One of five parts of the Special Olympics' Sports Skills Instructional Program, the booklet addresses ways to teach swimming and diving to mentally retarded students. Short term objectives of the program encompass warmup, basic swimming and diving skills, safety, and good sportsmanship. The long term goal focuses on acquisition of basic skills,…

  11. Scuba Diving and Kinesiology: Development of an Academic Program

    ERIC Educational Resources Information Center

    Kovacs, Christopher R.; Walter, Daniel

    2015-01-01

    The use of scuba diving as a recreational activity within traditional university instructional programs has been well established. Departments focusing on kinesiology, physical education, or exercise science have often provided scuba diving lessons as part of their activity-based course offerings. However, few departments have developed an…

  12. 29 CFR 1926.1083 - Post-dive procedures.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Post-dive procedures. Note: The requirements applicable to construction work under this section are... 29 Labor 8 2014-07-01 2014-07-01 false Post-dive procedures. 1926.1083 Section 1926.1083 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF...

  13. 29 CFR 1926.1083 - Post-dive procedures.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Post-dive procedures. Note: The requirements applicable to construction work under this section are... 29 Labor 8 2012-07-01 2012-07-01 false Post-dive procedures. 1926.1083 Section 1926.1083 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF...

  14. 29 CFR 1926.1083 - Post-dive procedures.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Post-dive procedures. Note: The requirements applicable to construction work under this section are... 29 Labor 8 2013-07-01 2013-07-01 false Post-dive procedures. 1926.1083 Section 1926.1083 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF...

  15. Aerobic Anoxygenic Phototrophic Bacteria

    PubMed Central

    Yurkov, Vladimir V.; Beatty, J. Thomas

    1998-01-01

    The aerobic anoxygenic phototrophic bacteria are a relatively recently discovered bacterial group. Although taxonomically and phylogenetically heterogeneous, these bacteria share the following distinguishing features: the presence of bacteriochlorophyll a incorporated into reaction center and light-harvesting complexes, low levels of the photosynthetic unit in cells, an abundance of carotenoids, a strong inhibition by light of bacteriochlorophyll synthesis, and the inability to grow photosynthetically under anaerobic conditions. Aerobic anoxygenic phototrophic bacteria are classified in two marine (Erythrobacter and Roseobacter) and six freshwater (Acidiphilium, Erythromicrobium, Erythromonas, Porphyrobacter, Roseococcus, and Sandaracinobacter) genera, which phylogenetically belong to the α-1, α-3, and α-4 subclasses of the class Proteobacteria. Despite this phylogenetic information, the evolution and ancestry of their photosynthetic properties are unclear. We discuss several current proposals for the evolutionary origin of aerobic phototrophic bacteria. The closest phylogenetic relatives of aerobic phototrophic bacteria include facultatively anaerobic purple nonsulfur phototrophic bacteria. Since these two bacterial groups share many properties, yet have significant differences, we compare and contrast their physiology, with an emphasis on morphology and photosynthetic and other metabolic processes. PMID:9729607

  16. U.K. deep diving trials.

    PubMed

    Hempleman, H V; Florio, J T; Garrard, M P; Harris, D J; Hayes, P A; Hennessy, T R; Nichols, G; Török, Z; Winsborough, M M

    1984-01-01

    Using a breathing medium of 40 kPa oxygen, remainder helium, 18 volunteer subjects participated in a series of 15 exposures to pressures equivalent to depths of 180-540 m s.w. The time of exposure at these pressures was mostly 2 days, except for the 540 m s.w. exposure, when 6 days were spent at full pressure. Compression procedures, based upon placing 'stages' at 60 m s.w. intervals, evolved with experience and proved to be a highly successful way of achieving acceptable pressure-time courses. Decompression combined slow linear release of pressure with overnight halts for sleep. On one occasion a depth of 660 m s.w. was reached by breathing 40 kPa oxygen, 10% nitrogen, remainder helium. Throughout all exposures, teams of investigators followed the changes in cardiovascular, respiratory, haematological, neurophysiological and metabolic status, and mental performance of the volunteers. Some major findings were that the neurophysiological and behavioural changes could be assigned to the motor, or vestibular, or cerebral, or autonomic systems, and were mainly first observed during compression. The subjects suffered, apparently from severe nitrogen narcosis, when breathing 10% (by volume) nitrogen in oxygen-helium at 420 m s.w. Lung ventilation was remarkably adaptable to the oxygen requirements of exercise at all depths, but cardiac output was adversely affected at 540 m s.w., particularly for heavier workloads. Ventilatory responses to carbon dioxide were significantly elevated after diving. Thermal balance was seen to be precarious, but nevertheless it was achieved by the normal subjective assessments of comfort. Water loss was affected by diminished evaporation from the skin. Skin temperature sensitivity was changed and took many days after the dives to return to normal. Energy requirements increased for work purposes, but basal metabolic rate was undisturbed. Body chemistry altered at pressures in excess of 300 m s.w., for example thyroid hormone and nitrogen

  17. Terminal dives in mink, muskrat and beaver.

    PubMed

    Gilbert, F F; Gofton, N

    1982-05-01

    Monitoring of EEG, EKG and overt behavior of mink, muskrat, and beaver caught in leg hold traps in an aquatic tank, showed marked differences by species. Death by CO2 induced narcosis (submersion asphyxia) was evident in beaver, about 50 percent of muskrat but "wet" drowning occurred in mink. Bradycardia was evident in all three species but was most pronounced in the beaver. Times to cessation of struggle, brain activity and heart activity indicated that the terminal dives of mink and muskrat, but not beaver, fell within the tentative criteria of humaneness for trapping devices established by the Federal Provincial Committee for Humane Trapping of Canada. PMID:7048357

  18. Aerobic Dance in Public Schools.

    ERIC Educational Resources Information Center

    Chiles, Barbara Ann; Moore, Suzanne

    1981-01-01

    Aerobic dance offers a challenging workout in a social atmosphere. Though some physical education instructors tend to exclude dance units from the curriculum, most could teach aerobic dance if they had a basic knowledge of aerobic routines. The outline for a unit to be used in the class is presented. (JN)

  19. Managing for Improved Aerobic Stability

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aerobic deterioration or spoilage of silage is the result of aerobic microorganisms metabolizing components of the silage using oxygen. In the almost 40 years over which these silage conferences have been held, we have come to recognize the typical pattern of aerobic microbial development by which s...

  20. The impact of consecutive freshwater trimix dives at altitude on human cardiovascular function.

    PubMed

    Lozo, Mislav; Madden, Dennis; Gunjaca, Grgo; Ljubkovic, Marko; Marinovic, Jasna; Dujic, Zeljko

    2015-03-01

    Self-contained underwater breathing apparatus (SCUBA) diving is regularly associated with numerous asymptomatic changes in cardiovascular function. Freshwater SCUBA diving presents unique challenges compared with open sea diving related to differences in water density and the potential for dive locations at altitude. The aim of this study was to evaluate the impact of freshwater trimix diving at altitude on human cardiovascular function. Ten divers performed two dives in consecutive days at 294 m altitude with the surface interval of 24 h. Both dives were at a depth of 45 m with total dive time 29 and 26 min for the first and second dive, respectively. Assessment of venous gas embolization, hydration status, cardiac function and arterial stiffness was performed. Production of venous gas emboli was low, and there were no significant differences between the dives. After the first dive, diastolic blood pressure was significantly reduced, which persisted up to 24 h. Left ventricular stroke volume decreased, and heart rate increased after both dives. Pulse wave velocity was unchanged following the dives. However, the central and peripheral augmentation index became more negative after both dives, indicating reduced wave reflection. Ejection duration and round trip travel time were prolonged 24 h after the first dive, suggesting longer-lasting suppression of cardiac and endothelial function. This study shows that freshwater trimix dives with conservative profiles and low venous gas bubble loads can result in multiple asymptomatic acute cardiovascular changes some of which were present up to 24 h after dive. PMID:24528802

  1. Dominance in cardiac parasympathetic activity during real recreational SCUBA diving.

    PubMed

    Chouchou, Florian; Pichot, Vincent; Garet, Martin; Barthélémy, Jean-Claude; Roche, Frédéric

    2009-06-01

    It was already established that exposure to hyperbaric conditions induces vagal-depended bradycardia but field study on autonomic nervous system (ANS) activity during self-contained underwater breathing apparatus (SCUBA) diving is lacking. The aim of the present study was to evaluate ANS modifications during real recreational SCUBA diving using heart rate variability analysis (timedomain, frequency-domain and Poincaré plot) in 10 experienced and volunteers recreational divers. Mean RR, root mean square of successive differences of interval (rMSSD), high frequency of spectral analysis and standard deviation 1 of Poincaré Plot increased (P < 0.05) during dive. Low frequency/high frequency ratio decreased during dive (P < 0.05) but increased after (P < 0.05). Recreational SCUBA diving induced a rise in vagal activity and a decrease in cardiac sympathetic activity. Conversely, sympathetic activity increases (P < 0.05) during the recovery. PMID:19277697

  2. Elevations in Intra-cranial blood flow velocities following a SCUBA Dive and the Influence of Post-dive Exercise.

    PubMed

    Barak, O F; Caljkusic, K; Madden, D; Ainslie, P N; Slavic, D; Buca, A; Dujic, Z

    2016-07-01

    The effect that a SCUBA dive has on cerebral blood flow (CBF) at rest and during exercise is poorly understood. We examined the hypothesis that the altered hemodynamic parameters following a SCUBA dive will lead to differential changes in CBF at rest and during exercise. 16 divers completed a field-based study with a single dive at a depth of 18 m sea water with a 47-min bottom time. A follow-up laboratory based study was conducted - 1 week later. Intra-cranial velocities were measured with transcranial Doppler ultrasound (TCD) pre-dive, post-dive at rest and throughout incremental exercise until exhaustion. Following the dive at rest, middle cerebral artery velocity (MCAv) was elevated 15 and 30 min after surfacing (by 3.3±5.8 and 4.0±6.9 cm/s, respectively; p<0.05); posterior cerebral artery velocity (PCAv) was increased at 30 min after surfacing (by 3.0±4.5 cm/s; p<0.05). During exercise following the dive, both MCAv and PCAv increased up to 150W followed by a decrease towards baseline at 180W (p<0.05). We found no difference in CBV during exercise between field and laboratory studies (p<0.05). The novel finding of this study is the transient elevation in resting intra-cranial velocities within 30 min following a SCUBA dive. PMID:27176888

  3. Otorhinolaryngologic disorders and diving accidents: an analysis of 306 divers.

    PubMed

    Klingmann, Christoph; Praetorius, Mark; Baumann, Ingo; Plinkert, Peter K

    2007-10-01

    Diving is a very popular leisure activity with an increasing number of participants. As more than 80% of the diving related problems involve the head and neck region, every otorhinolaryngologist should be familiar with diving medical standards. We here present an analysis of more than 300 patients we have treated in the past four years. Between January 2002 and October 2005, 306 patients presented in our department with otorhinological disorders after diving, or after diving accidents. We collected the following data: name, sex, age, date of treatment, date of accident, diagnosis, special aspects of the diagnosis, number of dives, diving certification, whether and which surgery had been performed, history of acute diving accidents or follow up treatment, assessment of fitness to dive and special remarks. The study setting was a retrospective cohort study. The distribution of the disorders was as follows: 24 divers (8%) with external ear disorders, 140 divers (46%) with middle ear disorders, 56 divers (18%) with inner ear disorders, 53 divers (17%) with disorders of the nose and sinuses, 24 divers (8%) with decompression illness (DCI) and 9 divers (3%) who complained of various symptoms. Only 18% of the divers presented with acute disorders. The most common disorder (24%) was Eustachian tube dysfunction. Female divers were significantly more often affected. Chronic sinusitis was found to be associated with a significantly higher number of performed dives. Conservative treatment failed in 30% of the patients but sinus surgery relieved symptoms in all patients of this group. The middle ear is the main problem area for divers. Middle ear ventilation problems due to Eustachian tube dysfunction can be treated conservatively with excellent results whereas pathology of the tympanic membrane and ossicular chain often require surgery. More than four out of five patients visited our department to re-establish their fitness to dive. Although the treatment of acute diving

  4. Diving-related fatalities caused by underwater explosions: a report of two cases.

    PubMed

    Petri, N M; Dujella, J; Definis-Gojanović, M; Vranjković-Petri, L; Cuculić, D

    2001-12-01

    The authors report two cases of diving-related water blast with fatal outcome resulting from nearby underwater explosions. Water blast with fatal outcome almost exclusively occurs in wars at sea. Underwater explosions are extremely rare in diving because of the limited exposure. Forensic findings in both cases reported included expected injuries to gas-filled organs such as the middle ear, lungs, and intestine; some rarely described injuries such as rupture of the liver, spleen, and kidneys; and also some lesions that were not found in a search of the literature: rupture of the heart and contusion of the hypophysis. Injuries caused by fatal underwater explosions should be carefully evaluated in forensic medicine to provide data that may support a criminal investigation. PMID:11764906

  5. Empirical evaluation of diving wet suit material heat transfer and thermal conductivity

    SciTech Connect

    West, P.B.

    1993-10-01

    This wet suit material testing program provides a quantitative thermal conductivity and heat transfer analysis, and comparison of various materials used in skin diving and SCUBA diving. Thermal resistance represents the primary subject examined, but due to compressibility of the baseline materials and its effect on heat transfer, this program also examines compression at simulated depth. This article reports the empirical heat transfer coefficients for both thermal conductivity and convection. Due to the limitations of the test apparatus, this analysis must restrict the convection evaluation to an approximately 20-cm-height, free-convection model. As a consequence, this model best simulates the overall heat transfer coefficient of a diver hovering in a horizontal position. This program also includes evaluations of some nonstandard materials in an effort to identify alternative wet suit materials.

  6. A Method for Identification of Some Components of Judging Springboard Diving.

    ERIC Educational Resources Information Center

    McCormick, James H.; And Others

    1982-01-01

    This study identifies critical elements of the front dive half-twist that judges are likely to look for when they score springboard diving competitions. Videotapes of divers at a 1979 intercollegiate diving meet were made and analyzed, using grid scoring procedures, to isolate components of the dives that would help predict judges' scores.…

  7. 29 CFR Appendix B to Subpart T of... - Guidelines for Scientific Diving

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 5 2014-07-01 2014-07-01 false Guidelines for Scientific Diving B Appendix B to Subpart T.... 1910, Subpt. T, App. B Appendix B to Subpart T of Part 1910—Guidelines for Scientific Diving This... scientific diving programs which are exempt from the requirements for commercial diving. The guidelines...

  8. 29 CFR Appendix B to Subpart T to... - Guidelines for Scientific Diving

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 5 2012-07-01 2012-07-01 false Guidelines for Scientific Diving B Appendix B to Subpart T.... 1910, Subpt. T, App. B Appendix B to Subpart T to Part 1910—Guidelines for Scientific Diving This... scientific diving programs which are exempt from the requirements for commercial diving. The guidelines...

  9. 29 CFR Appendix B to Subpart T of... - Guidelines for Scientific Diving

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 5 2013-07-01 2013-07-01 false Guidelines for Scientific Diving B Appendix B to Subpart T.... 1910, Subpt. T, App. B Appendix B to Subpart T of Part 1910—Guidelines for Scientific Diving This... scientific diving programs which are exempt from the requirements for commercial diving. The guidelines...

  10. Sympathetic Nerve Activity and Simulated Diving in Healthy Humans

    PubMed Central

    Shamsuzzaman, Abu; Ackerman, Michael J.; Kuniyoshi, Fatima Sert; Accurso, Valentina; Davison, Diane; Amin, Raouf S.; Somers, Virend K.

    2014-01-01

    The goal of our study was to develop a simple and practical method for simulating diving in humans using facial cold exposure and apnea stimuli to measure neural and circulatory responses during the stimulated diving reflex. We hypothesized that responses to simultaneous facial cold exposure and apnea (simulated diving) would be synergistic, exceeding the sum of responses to individual stimuli. We studied 56 volunteers (24 female and 32 male), average age 39 years. All subjects were healthy, free of cardiovascular and other diseases, and on no medications. Although muscle sympathetic nerve activity (MSNA), blood pressure, and vascular resistance increased markedly during both early and late phases of simulated diving, significant reductions in heart rate were observed only during the late phase. Total MSNA during simulated diving was greater than combined MSNA responses to the individual stimuli. We found that simulated diving is a powerful stimulus to sympathetic nerve traffic with significant bradycardia evident in the late phase of diving and eliciting synergistic sympathetic and parasympathetic responses. Our data provide insight into autonomic triggers that could help explain catastrophic cardiovascular events that may occur during asphyxia or swimming, such as in patients with obstructive sleep apnea and congenital long QT syndrome. PMID:24368150

  11. Asthma and recreational SCUBA diving: a systematic review.

    PubMed

    Koehle, Michael; Lloyd-Smith, Rob; McKenzie, Don; Taunton, Jack

    2003-01-01

    Asthma has traditionally been a contraindication to recreational self-contained underwater breathing apparatus (SCUBA) diving, although large numbers of patients with asthma partake in diving. The purpose of this paper is to review all the research relevant to the issue of the safety of asthma in divers. MEDLINE and MDConsult were searched for papers between 1980-2002. Keywords used for the search were 'asthma', 'SCUBA' and 'diving'. Additional references were reviewed from the bibliographies of received articles.A total of fifteen studies were identified as relevant to the area. These included three surveys of divers with asthma, four case series and eight mechanistic investigations of the effect of diving on pulmonary function. The survey data showed a high prevalence of asthma among recreational SCUBA divers, similar to the prevalence of asthma among the general population. There was some weak evidence for an increase in rates of decompression illness among divers with asthma. In healthy participants, wet hyperbaric chamber and open-water diving led to a decrease in forced vital capacity, forced expired volume over 1.0 second and mid-expiratory flow rates. In participants with asymptomatic respiratory atopy, diving caused a decrease in airway conductivity.There is some indication that asthmatics may be at increased risk of pulmonary barotrauma, but more research is necessary. Decisions regarding diving participation among asthmatics must be made on an individual basis involving the patient through informed, shared decision making. PMID:12617690

  12. Early diving behaviour in juvenile penguins: improvement or selection processes

    PubMed Central

    Weimerskirch, Henri; Bost, Charles-André

    2016-01-01

    The early life stage of long-lived species is critical to the viability of population, but is poorly understood. Longitudinal studies are needed to test whether juveniles are less efficient foragers than adults as has been hypothesized. We measured changes in the diving behaviour of 17 one-year-old king penguins Aptenodytes patagonicus at Crozet Islands (subantartic archipelago) during their first months at sea, using miniaturized tags that transmitted diving activity in real time. We also equipped five non-breeder adults with the same tags for comparison. The data on foraging performance revealed two groups of juveniles. The first group made shallower and shorter dives that may be indicative of early mortality while the second group progressively increased their diving depths and durations, and survived the first months at sea. This surviving group of juveniles required the same recovery durations as adults, but typically performed shallower and shorter dives. There is thereby a relationship between improved diving behaviour and survival in young penguins. This long period of improving diving performance in the juvenile life stage is potentially a critical period for the survival of deep avian divers and may have implications for their ability to adapt to environmental change. PMID:27484650

  13. Sympathetic nerve activity and simulated diving in healthy humans.

    PubMed

    Shamsuzzaman, Abu; Ackerman, Michael J; Kuniyoshi, Fatima Sert; Accurso, Valentina; Davison, Diane; Amin, Raouf S; Somers, Virend K

    2014-04-01

    The goal of our study was to develop a simple and practical method for simulating diving in humans using facial cold exposure and apnea stimuli to measure neural and circulatory responses during the stimulated diving reflex. We hypothesized that responses to simultaneous facial cold exposure and apnea (simulated diving) would be synergistic, exceeding the sum of responses to individual stimuli. We studied 56 volunteers (24 female and 32 male), average age of 39 years. All subjects were healthy, free of cardiovascular and other diseases, and on no medications. Although muscle sympathetic nerve activity (MSNA), blood pressure, and vascular resistance increased markedly during both early and late phases of simulated diving, significant reductions in heart rate were observed only during the late phase. Total MSNA during simulated diving was greater than combined MSNA responses to the individual stimuli. We found that simulated diving is a powerful stimulus to sympathetic nerve traffic with significant bradycardia evident in the late phase of diving and eliciting synergistic sympathetic and parasympathetic responses. Our data provide insight into autonomic triggers that could help explain catastrophic cardiovascular events that may occur during asphyxia or swimming, such as in patients with obstructive sleep apnea or congenital long QT syndrome. PMID:24368150

  14. Characteristics of diving in radio-marked Xantus's Murrelets

    USGS Publications Warehouse

    Hamilton, C.D.; Golightly, R.T.; Takekawa, J.Y.

    2005-01-01

    We monitored diving activity of radio-marked Xantus's Murrelets Synthliboramphus hypoleucus near Anacapa Island, California, during the breeding season. Thirteen radio-marked murrelets were remotely monitored from Anacapa Island with a handheld antenna and radio receiver for 29 hours in three sample periods in April and May 2003. Mean dive durations in the sample periods were 18 s ?? 2 s, 28 s ?? 2 s, and 24 s ?? 4 s, suggesting that dives were less than 21 m from the surface. Dive duration and subsequent time on the surface differed between the sample periods. Dive duration and subsequent time on the surface were not correlated in observations stratified by individual bird or by sample period. Further, dive duration and subsequent time on the surface were not correlated within foraging bouts. Dive characteristics measured near Anacapa Island suggested that Xantus's Murrelets have the ability to capture prey found at varying depths, but will feed on prey that is most available near the surface of the water.

  15. Optimal diving behaviour and respiratory gas exchange in birds.

    PubMed

    Halsey, Lewis G; Butler, Patrick J

    2006-11-01

    This review discusses the advancements in our understanding of the physiology and behaviour of avian diving that have been underpinned by optimal foraging theory and the testing of optimal models. To maximise their foraging efficiency during foraging periods, diving birds must balance numerous factors that are directly or indirectly related to the replenishment of the oxygen stores and the removal of excess carbon dioxide. These include (1) the time spent underwater (which diminishes the oxygen supply, increases carbon dioxide levels and may even include a build up of lactate due to anaerobic metabolism), (2) the time spent at the surface recovering from the previous dive and preparing for the next (including reloading their oxygen supply, decreasing their carbon dioxide levels and possibly also metabolising lactate) and (3) the trade-off between maximising oxygen reserves for consumption underwater by taking in more air to the respiratory system, and minimising the energy costs of positive buoyancy caused by this air, to maximise the time available underwater to forage. Due to its importance in avian diving, replenishment of the oxygen stores has become integral to models of optimal diving, which predict the time budgeting of animals foraging underwater. While many of these models have been examined qualitatively, such tests of predictive trends appear fallible and only quantifiable support affords strong evidence of their predictive value. This review describes how the quantification of certain optimal diving models, using tufted ducks, indeed demonstrates some predictive success. This suggests that replenishment of the oxygen stores and removal of excess carbon dioxide have significant influences on the duration of the surface period between dives. Nevertheless, present models are too simplistic to be robust predictors of diving behaviour for individual animals and it is proposed that they require refinement through the incorporation of other variables that also

  16. Open water scuba diving accidents at Leicester: five years' experience.

    PubMed Central

    Hart, A J; White, S A; Conboy, P J; Bodiwala, G; Quinton, D

    1999-01-01

    OBJECTIVES: The aim of this study was to determine the incidence, type, outcome, and possible risk factors of diving accidents in each year of a five year period presenting from one dive centre to a large teaching hospital accident and emergency (A&E) department. METHODS: All patients included in this study presented to the A&E department at a local teaching hospital in close proximity to the largest inland diving centre in the UK. Our main outcome measures were: presenting symptoms, administration of recompression treatment, mortality, and postmortem examination report where applicable. RESULTS: Overall, 25 patients experienced a serious open water diving accident at the centre between 1992 and 1996 inclusive. The percentage of survivors (n = 18) with symptoms of decompression sickness receiving recompression treatment was 52%. All surviving patients received medical treatment for at least 24 hours before discharge. The median depth of diving accidents was 24 metres (m) (range 7-36 m). During the study period, 1992-96, the number of accidents increased from one to 10 and the incidence of diving accidents increased from four per 100,000 to 15.4 per 100,000. Over the same time period the number of deaths increased threefold. CONCLUSIONS: The aetiology of the increase in the incidence of accidents is multifactorial. Important risk factors were thought to be: rapid ascent (in 48% of patients), cold water, poor visibility, the number of dives per diver, and the experience of the diver. It is concluded that there needs to be an increased awareness of the management of diving injuries in an A&E department in close proximity to an inland diving centre. PMID:10353047

  17. [Diagnosis and treatment of diving accidents. New German guidelines for diving accidents 2014-2017].

    PubMed

    Jüttner, B; Wölfel, C; Liedtke, H; Meyne, K; Werr, H; Bräuer, T; Kemmerer, M; Schmeißer, G; Piepho, T; Müller, O; Schöppenthau, H

    2015-06-01

    In 2015 the German Society for Diving and Hyperbaric Medicine (GTÜM) and the Swiss Underwater and Hyperbaric Medical Society (SUHMS) published the updated guidelines on diving accidents 2014-2017. These multidisciplinary guidelines were developed within a structured consensus process by members of the German Interdisciplinary Association for Intensive Care and Emergency Medicine (DIVI), the Sports Divers Association (VDST), the Naval Medical Institute (SchiffMedInst), the Social Accident Insurance Institution for the Building Trade (BG BAU), the Association of Hyperbaric Treatment Centers (VDD) and the Society of Occupational and Environmental Medicine (DGAUM). This consensus-based guidelines project (development grade S2k) with a representative group of developers was conducted by the Association of Scientific Medical Societies in Germany. It provides information and instructions according to up to date evidence to all divers and other lay persons for first aid recommendations to physician first responders and emergency physicians as well as paramedics and all physicians at therapeutic hyperbaric chambers for the diagnostics and treatment of diving accidents. To assist in implementing the guideline recommendations, this article summarizes the rationale, purpose and the following key action statements: on-site 100% oxygen first aid treatment, still patient positioning and fluid administration are recommended. Hyperbaric oxygen (HBO) recompression remains unchanged the established treatment in severe cases with no therapeutic alternatives. The basic treatment scheme recommended for diving accidents is hyperbaric oxygenation at 280 kPa. For quality management purposes there is a need in the future for a nationwide register of hyperbaric therapy. PMID:26025255

  18. Alveolar hemorrhage after scuba diving: a case report.

    PubMed

    Tsai, Ming-Ju; Tsai, Mee-Sun; Tsai, Ying-Ming; Lien, Chi-Tun; Hwang, Jhi-Jhu; Huang, Ming-Shyan

    2010-07-01

    Self-contained underwater breathing apparatus (scuba) diving is increasingly popular in Taiwan. There are few references in the literature regarding pulmonary hemorrhage as the sole manifestation of pulmonary barotrauma in scuba divers, and no study from Taiwan was found in the literature. We present the case of a 25-year-old man who suffered alveolar hemorrhage related to pulmonary barotrauma as a complication of scuba diving. To our knowledge, this is the first case report describing a Taiwanese subject suffering from non-fatal pulmonary hemorrhage after scuba diving. PMID:20638043

  19. A review of the forensic investigation of scuba diving deaths.

    PubMed

    Busuttil, A; Obafunwa, J

    1995-01-01

    With more people engaging in recreational scuba diving, fatalities from this sport are encountered by forensic investigators. There is a plethora of factors contributing to death and the investigator must be acquainted with how to elucidate them. The emphasis is on a multi-disciplinary approach that involves co-divers and instructors, the rescue team, the police, forensic scientists, diving equipment suppliers, underwater physiologists and physicians, decompression chamber personnel, general practitioners, relatives and the forensic pathologist. This report presents the various factors contributing to scuba diving deaths and suggests how to conduct such investigations. PMID:7606500

  20. [Medical certification for high altitude travel and scuba diving].

    PubMed

    Wuillemin, Timothée; Dos Santos Bragança, Angel; Ziltener, Jean-Luc; Berney, Jean-Yves; Lanier, Cédric

    2014-09-24

    People are more and more looking for adventures and discovery of unusual locations. Journeys to high altitude and scuba diving are part of these activities and their access has become easier for a lot of people not necessarily experienced with their dangers. The general practitioner will have to be able to deliver some advices and recommendations to his patients about the risks related to these activities and their ability to practice them. He will also have to deliver some certificates of medical fitness to dive. This paper proposes a brief review of the most important medical aspects to know about high altitude and scuba diving. PMID:25369697

  1. Energy cost and optimisation in breath-hold diving.

    PubMed

    Trassinelli, M

    2016-05-01

    We present a new model for calculating locomotion costs in breath-hold divers. Starting from basic mechanics principles, we calculate the work that the diver must provide through propulsion to counterbalance the action of drag, the buoyant force and weight during immersion. Compared to those in previous studies, the model presented here accurately analyses breath-hold divers which alternate active swimming with prolonged glides during the dive (as is the case in mammals). The energy cost of the dive is strongly dependent on these prolonged gliding phases. Here we investigate the length and impacts on energy cost of these glides with respect to the diver characteristics, and compare them with those observed in different breath-hold diving species. Taking into account the basal metabolic rate and chemical energy to propulsion transformation efficiency, we calculate optimal swim velocity and the corresponding total energy cost (including metabolic rate) and compare them with observations. Energy cost is minimised when the diver passes through neutral buoyancy conditions during the dive. This generally implies the presence of prolonged gliding phases in both ascent and descent, where the buoyancy (varying with depth) is best used against the drag, reducing energy cost. This is in agreement with past results (Miller et al., 2012; Sato et al., 2013) where, when the buoyant force is considered constant during the dive, the energy cost was minimised for neutral buoyancy. In particular, our model confirms the good physical adaption of dolphins for diving, compared to other breath-hold diving species which are mostly positively buoyant (penguins for example). The presence of prolonged glides implies a non-trivial dependency of optimal speed on maximal depth of the dive. This extends previous findings (Sato et al., 2010; Watanabe et al., 2011) which found no dependency of optimal speed on dive depth for particular conditions. The energy cost of the dive can be further

  2. Moving-objects extraction in diving video

    NASA Astrophysics Data System (ADS)

    Li, Yong; Liao, Qingmin

    2003-05-01

    This paper proposes a semiautomatic algorithm for the accurate extraction of an athlete from color diving sequences. Change detection techniques and edge detection techniques are combined to extract the moving object. Color information and interactive information are used to get rough region of the athlete interested. A robust edge map is derived from the difference between successive frames, then further refining of rough athlete region is applied by the information of the robust edge. The proposed method is useful in applications with a relatively still background, Experimental results show that the method provides accurate extraction with pixel-wise precision, thus providing a reliable input to further analysis or applications such as MPEG-4.

  3. The mechanistic basis of aerobic performance variation in red junglefowl.

    PubMed

    Hammond, K A; Chappell, M A; Cardullo, R A; Lin, R; Johnsen, T S

    2000-07-01

    We examined aerobic performance, organ and muscle mass and enzymatic activity in red junglefowl (Gallus gallus). We tested three models of performance limitation (central limits, peripheral limits, symmorphosis) and explored relationships between basal metabolic rate (BMR), aerobic capacity ( V (O2max)) and social rank. Males had a lower BMR, a higher V (O2max) and a greater aerobic scope than females. Females possessed larger peritoneal and reproductive organs, while males had larger hearts, lungs and leg muscles. In females, BMR was correlated with spleen mass and V (O2max) was correlated with hematocrit and large intestine mass. Male BMR was correlated with intestinal tract and lung mass, and V (O2max) was correlated with heart and pectoralis mass. Male citrate synthase activity averaged 57 % higher than that of females and was correlated with V (O2max) (this correlation was not significant in females). Female social status was not correlated with any variable, but male dominance was associated with higher aerobic scope, larger heart and lungs, smaller peritoneal organs and greater leg citrate synthase activity. We conclude that aerobic capacity is controlled by system-wide limitations (symmorphosis) in males, while in females it is controlled by central organs. In neither sex is elevated aerobic capacity associated with increased maintenance costs. PMID:10851122

  4. Kinetic and dynamic models of diving gases in decompression sickness prevention.

    PubMed

    Ball, Robert; Schwartz, Sorell L

    2002-01-01

    Decompression sickness is a complex phenomenon involving gas exchange, bubble dynamics and tissue response. Relatively simple deterministic compartmental models using empirically derived parameters have been the mainstay of the practice for preventing decompression sickness since the early 1900s. Decades of research have improved our understanding of decompression physiology, and the insights incorporated in decompression models have allowed people to dive deeper into the ocean. However, these efforts have not yet, and are unlikely in the near future, to result in a 'universal' deterministic model that can predict when decompression sickness will occur. Divers using current recreational dive computers need to be aware of their limitations. Probabilistic models based on the estimation of parameters using modern statistical methods from large databases of dives offer a new approach and can provide a means of standardisation of deterministic models. Future improvements in decompression practice will depend on continued improvement in understanding the kinetics and dynamics of gas exchange, bubble evolution and tissue response, and the incorporation of this knowledge in risk models whose parameters can be estimated from large databases of human and animal data. PMID:12074688

  5. Cardiovascular changes during underwater static and dynamic breath-hold dives in trained divers.

    PubMed

    Breskovic, Toni; Uglesic, Lovro; Zubin, Petra; Kuch, Benjamin; Kraljevic, Jasenka; Zanchi, Jaksa; Ljubkovic, Marko; Sieber, Arne; Dujic, Zeljko

    2011-09-01

    Limited information exists concerning arterial blood pressure (BP) changes in underwater breath-hold diving. Simulated chamber dives to 50 m of freshwater (mfw) reported very high levels of invasive BP in two divers during static apnea (SA), whereas a recent study using a noninvasive subaquatic sphygmomanometer reported unchanged or mildly increased values at 10 m SA dive. In this study we investigated underwater BP changes during not only SA but, for the first time, dynamic apnea (DA) and shortened (SHT) DA in 16 trained breath-hold divers. Measurements included BP (subaquatic sphygmomanometer), ECG, and pulse oxymetry (arterial oxygen saturation, SpO₂, and heart rate). BP was measured during dry conditions, at surface fully immersed (SA), and at 2 mfw (DA and SHT DA), whereas ECG and pulse oxymetry were measured continuously. We have found significantly higher mean arterial pressure (MAP) values in SA (∼40%) vs. SHT DA (∼30%). Postapneic recovery of BP was slightly slower after SHT DA. Significantly higher BP gain (mmHg/duration of apnea in s) was found in SHT DA vs. SA. Furthermore, DA attempts resulted in faster desaturation vs. SA. In conclusion, we have found moderate increases in BP during SA, DA, and SHT DA. These cardiovascular changes during immersed SA and DA are in agreement with those reported for dry SA and DA. PMID:21719730

  6. SCUBA Diving for Blind and Visually Impaired People.

    ERIC Educational Resources Information Center

    Candela, Anthony R.

    1982-01-01

    The author, a trained scuba (self-contained underwater breathing apparatus) diver who is severely visually impaired provides an orientation to scuba diving as a leisure and career activity. (Author/SB)

  7. The source of circulating catecholamines in forced dived ducks.

    PubMed

    Lacombe, A M; Jones, D R

    1990-10-01

    Plasma catecholamines have been measured in chronically adrenalectomized (ADX) ducks, in chronically adrenal-denervated ducks (DNX), and in their respective shamoperated controls (SH-adx, SH-dnx) after 3 min forced submergence. The results showed that 100% of the plasma epinephrine (EP) and 70 to 80% of plasma norepinephrine (NE) released during the dive came from the adrenal glands. Only 20 to 30% of plasma NE came from the endings of the autonomic vascular sympathetic nerves which are strongly stimulated during diving. Adrenal catecholamines were released by nerve activation only; nonneural mechanisms did not play any role in their release. The action of adrenal catecholamines on the cardiovascular system during dives was investigated by measuring heart rate and arterial blood pressure in operated and sham-operated ducks. Cardiovascular adjustments, associated with 3 min of forced diving, were not affected by any differences in the levels of plasma catecholamines. PMID:2272478

  8. Differential air sac pressures in diving tufted ducks Aythya fuligula.

    PubMed

    Boggs, D F; Butler, P J; Wallace, S E

    1998-09-01

    The air in the respiratory system of diving birds contains a large proportion of the body oxygen stores, but it must be in the lungs for gas exchange with blood to occur. To test the hypothesis that locomotion induces mixing of air sac air with lung air during dives, we measured differential pressures between the interclavicular and posterior thoracic air sacs in five diving tufted ducks Aythya fuligula. The peak differential pressure between posterior thoracic and interclavicular air sacs, 0.49+/-0.13 kPa (mean +/- s.d.), varied substantially during underwater paddling as indicated by gastrocnemius muscle activity. These data support the hypothesis that locomotion, perhaps through associated abdominal muscle activity, intermittently compresses the posterior air sacs more than the anterior ones. The result is differential pressure fluctuations that might induce the movement of air between air sacs and through the lungs during dives. PMID:9716518

  9. The Risks of Scuba Diving: A Focus on Decompression Illness

    PubMed Central

    2014-01-01

    Decompression Illness includes both Decompression Sickness (DCS) and Pulmonary Overinflation Syndrome (POIS), subsets of diving-related injury related to scuba diving. DCS is a condition in which gas bubbles that form while diving do not have adequate time to be resorbed or “off-gassed,” resulting in entrapment in specific regions of the body. POIS is due to an overly rapid ascent to the surface resulting in the rupture of alveoli and subsequent extravasation of air bubbles into tissue planes or even the cerebral circulation. Divers must always be cognizant of dive time and depth, and be trained in the management of decompression. A slow and controlled ascent, plus proper control of buoyancy can reduce the dangerous consequences of pulmonary barotrauma. The incidence of adverse effects can be diminished with safe practices, allowing for the full enjoyment of this adventurous aquatic sport. PMID:25478296

  10. Bubble trouble: a review of diving physiology and disease.

    PubMed

    Levett, D Z H; Millar, I L

    2008-11-01

    Exposure to the underwater environment for recreational or occupational purposes is increasing. Approximately 7 million divers are active worldwide and 500,000 more are training every year. Diving related illnesses are consequently an increasingly common clinical problem with over 1000 cases of decompression illness reported annually in the USA alone. Divers are exposed to a number of physiological risks as a result of the hyperbaric underwater environment including: the toxic effects of hyperbaric gases, the respiratory effects of increased gas density, drowning, hypothermia and bubble related pathophysiology. Understanding the nature of this pathophysiology provides insight into physiological systems under stress and as such may inform translational research relevant to clinical medicine. We will review current diving practice, the physics and physiology of the hyperbaric environment, and the pathophysiology and treatment of diving related diseases. We will discuss current developments in diving research and some potential translational research areas. PMID:19103814

  11. 23. VIEW, FROM EAST, SHOWING DIVING AND MAIN POOLS AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    23. VIEW, FROM EAST, SHOWING DIVING AND MAIN POOLS AND WEST ELEVATION OF OFFICE AND FIRST AID BUILDING - Glen Echo Park, Crystal Swimming Pool, 7300 McArthur Boulevard, Glen Echo, Montgomery County, MD

  12. The risks of scuba diving: a focus on Decompression Illness.

    PubMed

    Hall, Jennifer

    2014-11-01

    Decompression Illness includes both Decompression Sickness (DCS) and Pulmonary Overinflation Syndrome (POIS), subsets of diving-related injury related to scuba diving. DCS is a condition in which gas bubbles that form while diving do not have adequate time to be resorbed or "off-gassed," resulting in entrapment in specific regions of the body. POIS is due to an overly rapid ascent to the surface resulting in the rupture of alveoli and subsequent extravasation of air bubbles into tissue planes or even the cerebral circulation. Divers must always be cognizant of dive time and depth, and be trained in the management of decompression. A slow and controlled ascent, plus proper control of buoyancy can reduce the dangerous consequences of pulmonary barotrauma. The incidence of adverse effects can be diminished with safe practices, allowing for the full enjoyment of this adventurous aquatic sport. PMID:25478296

  13. The development of hyperbaric and diving medicine in Singapore.

    PubMed

    Chng, J; Low, C T; Kang, W L

    2011-12-01

    Hyperbaric oxygen therapy is a noninvasive therapy used in the treatment of diving-related medical illnesses. It is an important adjunct in the management of a variety of medical conditions. The Republic of Singapore Navy Medical Service (NMS) is the main driver of the development of hyperbaric and diving medicine in Singapore. The practice of hyperbaric medicine has inherent risks, and unregulated application of this therapy may do more harm than good. NMS and Singapore General Hospital (SGH) signed a Memorandum of Understanding to combine NMS' experience with the clinical expertise of SGH to provide holistic care for diving and clinical hyperbaric treatment patients. This collaboration would increase the profile of this clinical specialty in Singapore, and help to establish safe clinical practice guidelines, training and accreditation requirements for diving and hyperbaric medicine practitioners in Singapore, thus ensuring that the practice of bona fide hyperbaric medicine is safeguarded and patient care is not compromised. PMID:22159934

  14. Aerobic landfill bioreactor

    DOEpatents

    Hudgins, Mark P; Bessette, Bernard J; March, John C; McComb, Scott T.

    2002-01-01

    The present invention includes a system of decomposing municipal solid waste (MSW) within a landfill by converting the landfill to aerobic degradation in the following manner: (1) injecting air via the landfill leachate collection system (2) injecting air via vertical air injection wells installed within the waste mass; (3) applying leachate to the waste mass using a pressurized drip irrigation system; (4) allowing landfill gases to vent; and (5) adjusting air injection and recirculated leachate to achieve a 40% to 60% moisture level and a temperature between 120.degree. F. and 140.degree. F. in steady state.

  15. Aerobic landfill bioreactor

    DOEpatents

    Hudgins, Mark P; Bessette, Bernard J; March, John; McComb, Scott T.

    2000-01-01

    The present invention includes a method of decomposing municipal solid waste (MSW) within a landfill by converting the landfill to aerobic degradation in the following manner: (1) injecting air via the landfill leachate collection system (2) injecting air via vertical air injection wells installed within the waste mass; (3) applying leachate to the waste mass using a pressurized drip irrigation system; (4) allowing landfill gases to vent; and (5) adjusting air injection and recirculated leachate to achieve a 40% to 60% moisture level and a temperature between 120.degree. F. and 140.degree. F. in steady state.

  16. The mammalian diving response: an enigmatic reflex to preserve life?

    PubMed

    Panneton, W Michael

    2013-09-01

    The mammalian diving response is a remarkable behavior that overrides basic homeostatic reflexes. It is most studied in large aquatic mammals but is seen in all vertebrates. Pelagic mammals have developed several physiological adaptations to conserve intrinsic oxygen stores, but the apnea, bradycardia, and vasoconstriction is shared with those terrestrial and is neurally mediated. The adaptations of aquatic mammals are reviewed here as well as the neural control of cardiorespiratory physiology during diving in rodents. PMID:23997188

  17. Selective brain cooling and its vascular basis in diving seals.

    PubMed

    Blix, Arnoldus Schytte; Walløe, Lars; Messelt, Edward B; Folkow, Lars P

    2010-08-01

    Brain (T(brain)), intra-aorta (T(aorta)), latissimus dorsi muscle (T(m)) and rectal temperature (T(r)) were measured in harp (Pagophilus groenlandicus) and hooded (Cystophora cristata) seals during experimental dives in 4 degrees C water. The median brain cooling was about 1 degrees C during 15 min diving, but in some cases it was as much as 2.5 degrees C. Cooling rates were slow for the first couple of minutes, but increased significantly after about 5 min of diving. The onset of cooling sometimes occurred before the start of the dive, confirming that the cooling is under cortical control, like the rest of the diving responses. T(aorta) also fell significantly, and was always lower than T(brain), while T(m) was fairly stable during dives. Detailed studies of the vascular anatomy of front flippers revealed that brachial arterial blood can be routed either through flipper skin capillaries for nutritive purposes and return through sophisticated vascular heat exchangers to avoid heat loss to the environment, or, alternatively, through numerous arterio-venous shunts in the skin and return by way of large superficial veins, which then carry cold blood to the heart. In the latter situation the extent to which the brain is cooled is determined by the ratio of carotid to brachial arterial blood flow, and water temperature, and the cooling is selective in that only those organs that are circulated will be cooled. It is concluded that T(brain) is actively down-regulated during diving, sometimes by as much as 2.5 degrees C, whereby cerebral oxygen requirements may be reduced by as much as 25% during extended dives. PMID:20639422

  18. The Mammalian Diving Response: An Enigmatic Reflex to Preserve Life?

    PubMed Central

    2013-01-01

    The mammalian diving response is a remarkable behavior that overrides basic homeostatic reflexes. It is most studied in large aquatic mammals but is seen in all vertebrates. Pelagic mammals have developed several physiological adaptations to conserve intrinsic oxygen stores, but the apnea, bradycardia, and vasoconstriction is shared with those terrestrial and is neurally mediated. The adaptations of aquatic mammals are reviewed here as well as the neural control of cardiorespiratory physiology during diving in rodents. PMID:23997188

  19. Antioxidants may Attenuate Plasma Erythropoietin Decline after Hyperbaric Oxygen Diving.

    PubMed

    Mutzbauer, T S; Schneider, M; Neubauer, B; Weiss, M; Tetzlaff, K

    2015-11-01

    According to previous studies, plasma erythropoietin (EPO) may decrease after hyperbaric oxygen exposure due to oxidative stress. It is hypothesized that the decrease of EPO can be attenuated by oxygen free radical scavengers.The aim of the present study was to evaluate whether EPO plasma levels can be influenced by oral application of vitamin C and E before repeated hyperbaric oxygen exposure during diving. 16 healthy male police task force divers performed 3 morning dives on oxygen within a regular diving schedule on 3 consecutive days. They were randomized into either the placebo group or the vitamin group, receiving 1 g ascorbic acid and 600 IU D-α-tocopherol orally 60 min before the dive. Blood samples for EPO measurement were taken on days 1, 2, and 3 at T1, T3 and T5 60 min before and at T2, T4 and T6 60 min after each dive, respectively. A moderate decrease of EPO was observed beginning at T3 until T6 in the placebo group. The EPO concentrations in the vitamin group did not show relevant variations compared to baseline. Radical scavenging vitamins C and D may counteract hyperbaric oxygen related mechanisms reducing EPO production in hyperbaric oxygen exposure during diving. PMID:26258821

  20. Acute ischemic colitis secondary to air embolism after diving

    PubMed Central

    Payor, Austin Daniel; Tucci, Veronica

    2011-01-01

    Ischemic colitis (IC) secondary to air embolism from decompression sickness or barotrauma during diving is an extremely rare condition. After extensive review of the available literature, we found that there has been only one reported case of IC secondary to air embolism from diving. Although air embolization from diving and the various medical complications that follow have been well documented, the clinical manifestation of IC from an air embolism during diving is very rare and thus far unstudied. Common symptoms of IC include abdominal pain, bloody or non-bloody diarrhea or nausea or vomiting or any combination. Emergency physicians and Critical Care specialists should consider IC as a potential diagnosis for a patient with the above-mentioned symptoms and a history of recent diving. We report a case of IC from air embolism after a routine dive to 75 feet below sea level in a 53-year-old White female who presented to a community Emergency Department complaining of a 2-day history of diffuse abdominal pain and nausea. She was diagnosed by colonoscopy with biopsies and treated conservatively with antibiotics, bowel rest, and a slow advancement in diet. PMID:22096777

  1. Activation of brainstem neurons by underwater diving in the rat.

    PubMed

    Panneton, W Michael; Gan, Qi; Le, Jason; Livergood, Robert S; Clerc, Philip; Juric, Rajko

    2012-01-01

    The mammalian diving response is a powerful autonomic adjustment to underwater submersion greatly affecting heart rate, arterial blood pressure, and ventilation. The bradycardia is mediated by the parasympathetic nervous system, arterial blood pressure is mediated via the sympathetic system and still other circuits mediate the respiratory changes. In the present study we investigate the cardiorespiratory responses and the brainstem neurons activated by voluntary diving of trained rats, and, compare them to control and swimming animals which did not dive. We show that the bradycardia and increase in arterial blood pressure induced by diving were significantly different than that induced by swimming. Neuronal activation was calculated after immunohistochemical processing of brainstem sections for Fos protein. Labeled neurons were counted in the caudal pressor area, the medullary dorsal horn, subnuclei of the nucleus tractus solitarii (NTS), the nucleus raphe pallidus (RPa), the rostroventrolateral medulla, the A5 area, the nucleus locus coeruleus, the Kölliker-Fuse area, and the external lateral and superior lateral subnuclei of the parabrachial nucleus. All these areas showed significant increases in Fos labeling when data from voluntary diving rats were compared to control rats and all but the commissural subnucleus of the NTS, A5 area, and RPa were significantly different from swimming rats. These data provide a substrate for more precise experiments to determine the role of these nuclei in the reflex circuits driving the diving response. PMID:22563319

  2. Function of head-bobbing behavior in diving little grebes.

    PubMed

    Gunji, Megu; Fujita, Masaki; Higuchi, Hiroyoshi

    2013-08-01

    Most birds show a characteristic head movement that consists of head stabilization and quick displacement. In this movement, which is analogous to saccadic eye movement in mammals, head stabilization plays an important role in stabilizing the retinal image. This head movement, called "head bobbing", is particularly pronounced during walking. Previous studies focusing on anatomical and behavioral features have pointed out that visual information is also important for diving birds, indicating its significance in the head movements of diving birds. In the present study, the kinematic and behavioral features of head bobbing in diving little grebes were described by motion analysis to identify the head movement in diving birds. The results showed that head-bobbing stroke (HBS) consisted of a thrust phase and a hold phase as is typical for head bobbing during walking birds. This suggests that HBS is related to visual stabilization under water. In HBS, grebes tended to dive with longer stroke length and smaller stroke frequency than in non-bobbing stroke. This suggests that the behavior, which is related to vision, affects the kinematic stroke parameters. This clarification of underwater head movement will help in our understanding not only of vision, but also of the kinematic strategy of diving birds. PMID:23723051

  3. Activation of Brainstem Neurons by Underwater Diving in the Rat

    PubMed Central

    Panneton, W. Michael; Gan, Qi; Le, Jason; Livergood, Robert S.; Clerc, Philip; Juric, Rajko

    2012-01-01

    The mammalian diving response is a powerful autonomic adjustment to underwater submersion greatly affecting heart rate, arterial blood pressure, and ventilation. The bradycardia is mediated by the parasympathetic nervous system, arterial blood pressure is mediated via the sympathetic system and still other circuits mediate the respiratory changes. In the present study we investigate the cardiorespiratory responses and the brainstem neurons activated by voluntary diving of trained rats, and, compare them to control and swimming animals which did not dive. We show that the bradycardia and increase in arterial blood pressure induced by diving were significantly different than that induced by swimming. Neuronal activation was calculated after immunohistochemical processing of brainstem sections for Fos protein. Labeled neurons were counted in the caudal pressor area, the medullary dorsal horn, subnuclei of the nucleus tractus solitarii (NTS), the nucleus raphe pallidus (RPa), the rostroventrolateral medulla, the A5 area, the nucleus locus coeruleus, the Kölliker–Fuse area, and the external lateral and superior lateral subnuclei of the parabrachial nucleus. All these areas showed significant increases in Fos labeling when data from voluntary diving rats were compared to control rats and all but the commissural subnucleus of the NTS, A5 area, and RPa were significantly different from swimming rats. These data provide a substrate for more precise experiments to determine the role of these nuclei in the reflex circuits driving the diving response. PMID:22563319

  4. Atopy, airway reactivity and compressed air diving in males.

    PubMed

    Tetzlaff, K; Neubauer, B; Reuter, M; Friege, L

    1998-01-01

    A decline in expiratory flow rates in divers has recently been attributed to chronic exposure to hyberbaric air. Airway hyperresponsiveness (AHR) to stimuli due to a hyperbaric environment may play a certain role in this context. The aim of this study was to determine the prevalence of AHR in compressed air divers and to assess the value of bronchial challenges for prediction of fitness to dive. A cross-sectional sample of 59 healthy male volunteers--28 divers and 31 diving candidates (controls)--who had been found fit to dive in a diving medical examination underwent additional allergy screening (skin prick and serum IgE) and a histamine bronchial challenge. Pre- and postchallenge body plethysmography was completed to assess AHR. AHR to histamine was significantly increased among divers and positively related to diving experience whereas divers and controls did not differ significantly with respect to age, anthropometric data, current smoking habits, skin prick reaction, and elevated serum IgE. Our results indicate an increased prevalence of AHR to nonspecific inhalation stimuli in experienced divers. Bronchial challenge tests may be helpful to detect asthmatics in the medical assessment of fitness to dive and for follow-up examinations during a diver's career. PMID:9730792

  5. Sequential anaerobic/aerobic biotreatment of bark leachate.

    PubMed

    Frigon, J C; Cimpoia, R; Guiot, S R

    2003-01-01

    Bark leachate is generated from sawmill operations such as log storage sites and contains polymeric tannins, carbohydrates, organic acids, phenolic and resin compounds. The present study was aimed at assessing the performance of a sequential anaerobic and aerobic treatment, for both chemical oxygen demand (COD) and phenol removal, under various combinations of operational conditions, in the continuous mode. After anaerobic treatment in a five litres upflow anaerobic sludge bed (UASB) reactor, the leachate was directed into two parallel aerobic reactors, either an activated sludge unit or a fixed film submerged filter (packed with polyethylene Flexirings), both of a volume of one litre and oxygenated by air diffusion. For a leachate of 22 gCOD/l, an overall COD removal of 96-98% was achieved at an hydraulic residence time (HRT) of 4 days for the anaerobic reactor and one day for either aerobic systems. The phenol concentration generally increased after anaerobic treatment but was below the detection limit (50 ppb) after aerobic polishing. Radiorespirometric microcosms with 14C-labelled phenol confirmed that phenol was mineralized in the aerobic reactors. The performances of both aerobic systems were similar for COD and phenol removal. Thus, a sequential anaerobic/aerobic treatment was able to effectively address the contamination of a bark leachate discharge, including phenols. PMID:14640219

  6. Petrochemical Results for Volcanic Rocks recovered from SHINKAI 6500 diving on the Bonin Ridge (27°15'N-28°25'N): submarine extension of Ogasawara forearc volcanism

    NASA Astrophysics Data System (ADS)

    Bloomer, S. H.; Kimura, J.; Stern, R. J.; Ohara, Y.; Ishii, T.; Ishizuka, O.; Haraguchi, S.; Machida, S.; Reagan, M.; Kelley, K.; Hargrove, U.; Wortel, M.; Li, Y. B.

    2004-12-01

    Hf concentrations. Our new data indicate that Haha-jima type depleted tholeiites may be widespread along the northern part of the escarpment west of the Bonin Ridge, whereas occurrence of boninite is limited to the region adjacent to Chichi-jima Islands. Segmentation of boninite distribution may be related to an eastward bathymetric indentation of the scarp between Chichi-jima and Muko-jima. Temporal relationships between Eocene tholeiites and boninites of the islands and those recovered by diving await the results of dating and further geological investigations.

  7. Aerobic Fitness and School Children.

    ERIC Educational Resources Information Center

    Hinkle, J. Scott

    1997-01-01

    Provides school counselors with information on aerobic exercise (specifically running) and the psychological, behavioral, and physical benefits children obtained by participating in fitness programs. Recommends collaboration between school counselors and physical education teachers and gives a preliminary discussion of aerobic running and its…

  8. Aerobic Fitness and School Children.

    ERIC Educational Resources Information Center

    Hinkle, J. Scott

    1992-01-01

    Provides school counselors with information regarding aerobic exercise (specifically running), and the psychological, behavioral, and physical benefits children obtain by participating in fitness programs. Presents methods of collaboration between school counselors and physical education teachers. Offers preliminary discussion of aerobic running…

  9. Exercise, Animal Aerobics, and Interpretation?

    ERIC Educational Resources Information Center

    Oliver, Valerie

    1996-01-01

    Describes an aerobic activity set to music for children that mimics animal movements. Example exercises include walking like a penguin or jumping like a cricket. Stresses basic aerobic principles and designing the program at the level of children's motor skills. Benefits include reaching people who normally don't visit nature centers, and bridging…

  10. Heart rate variability in free diving athletes.

    PubMed

    Christoforidi, Vassiliki; Koutlianos, Nikolaos; Deligiannis, Pantazis; Kouidi, Evangelia; Deligiannis, Asterios

    2012-03-01

    The aim of the study was to evaluate the cardiac autonomic activity in free diving (FD) athletes. Thirteen Greek male free divers (group I, aged 33.4 ± 6.3 years, 6.6 ± 4.5 years of training experience) volunteered to participate while 13 age-matched sedentary subjects served as control group (group II). All subjects were submitted to ambulatory 24-h ECG recording for heart rate variability (HRV) analysis on a day of regular activities with no exercise or training. The results showed that group I had significantly lower minimum and mean heart rate by 23.9% (P < 0.001) and 20.6% (P < 0.001), respectively. All the measured time and frequency domain indices of HRV which reflect cardiac parasympathetic activity were higher in group I than in group II by 37.6% to 146% (P < 0.001). Conclusively, the resting cardiac autonomic activity and especially the parasympathetic branch was significantly increased in free divers compared to untrained subjects. This finding should be rather attributed to the accumulated effect of both exercise training and frequent exposure to FD stimulus. PMID:22296638

  11. Influence of scuba diving on asymptomatic isolated pulmonary bullae.

    PubMed

    Germonpré, Peter; Balestra, Costantino; Pieters, Thierry

    2008-12-01

    Pulmonary blebs and bullae are generally considered an absolute contra-indication for scuba diving, because of a high estimated risk of pulmonary overpressure syndrome due to air-trapping inside the bulla. This is primarily based on a number of retrospective studies and case reports; formal prospective evidence of a higher risk is lacking. We present three cases where a pulmonary bulla was radiographically shown to increase in diameter, seemingly related to scuba diving activity, and causing ultimately a barotraumatic diving accident. These cases provide pathophysiological clues as to how even an isolated, non-ventilated bulla can be the cause of pulmonary barotrauma. The most likely mechanism for this phenomenon is a 'stretching' of the bulla upon ascent from the dive: after a period of compression (Boyle's Law), there is a gradual diffusion of air through the bulla wall, with restoration to its initial size by the end of the dive. Upon ascent, the air diffuses only slowly out of the bulla, causing a temporary increase in diameter and stretching of the bulla wall. This repeated stretching causes the bulla to grow gradually. At one point, the cyst wall may become critically thin and rupture during the ascent. PMID:22692754

  12. Hyperbaric oxygen diving affects exhaled molecular profiles in men.

    PubMed

    van Ooij, P J A M; van Hulst, R A; Kulik, W; Brinkman, P; Houtkooper, A; Sterk, P J

    2014-07-01

    Exhaled breath contains volatile organic compounds (VOCs) that are associated with respiratory pathophysiology. We hypothesized that hyperbaric oxygen exposure (hyperoxia) generates a distinguishable VOC pattern. This study aimed to test this hypothesis in oxygen-breathing divers. VOCs in exhaled breath were measured in 10 male divers before and 4h after diving to 9msw (190kPa) for 1h. During the dive they breathed 100% oxygen or air in randomized order. VOCs were determined using two-dimensional gas chromatography with time-of-flight mass spectrometry. Compared to air dives, after oxygen dives there was a significant increase in five VOCs (predominately methyl alkanes). Furthermore, a strong, positive correlation was found between increments in 2,4-dimethyl-hexane and those of 4-ethyl-5-methyl-nonane. Although non-submerged hyperoxia studies on VOCs have been performed, the present study is the first to demonstrate changes in exhaled molecular profiles after submerged oxygen diving. The pathophysiological background might be attributed to either a lipid peroxidation-induced pathway, an inflammatory pathway, or to both. PMID:24703972

  13. Dive and Explore: An Interactive Web Visualization that Simulates Making an ROV Dive to an Active Submarine Volcano

    NASA Astrophysics Data System (ADS)

    Weiland, C.; Chadwick, W. W.

    2004-12-01

    Several years ago we created an exciting and engaging multimedia exhibit for the Hatfield Marine Science Center that lets visitors simulate making a dive to the seafloor with the remotely operated vehicle (ROV) named ROPOS. The exhibit immerses the user in an interactive experience that is naturally fun but also educational. The public display is located at the Hatfield Marine Science Visitor Center in Newport, Oregon. We are now completing a revision to the project that will make this engaging virtual exploration accessible to a much larger audience. With minor modifications we will be able to put the exhibit onto the world wide web so that any person with internet access can view and learn about exciting volcanic and hydrothermal activity at Axial Seamount on the Juan de Fuca Ridge. The modifications address some cosmetic and logistic ISSUES confronted in the museum environment, but will mainly involve compressing video clips so they can be delivered more efficiently over the internet. The web version, like the museum version, will allow users to choose from 1 of 3 different dives sites in the caldera of Axial Volcano. The dives are based on real seafloor settings at Axial seamount, an active submarine volcano on the Juan de Fuca Ridge (NE Pacific) that is also the location of a seafloor observatory called NeMO. Once a dive is chosen, then the user watches ROPOS being deployed and then arrives into a 3-D computer-generated seafloor environment that is based on the real world but is easier to visualize and navigate. Once on the bottom, the user is placed within a 360 degree panorama and can look in all directions by manipulating the computer mouse. By clicking on markers embedded in the scene, the user can then either move to other panorama locations via movies that travel through the 3-D virtual environment, or they can play video clips from actual ROPOS dives specifically related to that scene. Audio accompanying the video clips informs the user where they are

  14. Activation of the trigeminal medullary dorsal horn during voluntary diving in rats.

    PubMed

    McCulloch, Paul F

    2005-07-27

    Fos immunohistochemistry was used to indicate whether activation of trigeminal neurons occurs in voluntarily diving rats. In rats trained to dive underwater, significant increases in Fos labeling were found within the ventral superficial MDH and paratrigeminal nucleus, 100-150 microm caudal to the obex compared to control rats. The conclusion is that the ventral superficial MDH is the initial brainstem afferent relay of diving response in voluntarily diving rats. PMID:15978555

  15. Enhanced selection of micro-aerobic pentachlorophenol degrading granular sludge.

    PubMed

    Lv, Yuancai; Chen, Yuancai; Song, Wenzhe; Hu, Yongyou

    2014-09-15

    Column-type combined reactors were designed to cultivate micro-aerobic pentachlorophenol (PCP) degrading granular sludge under oxygen-limited conditions (0.1-0.2 mgL(-1)) over 39-day experimental period. Micro-aerobic granular had both anaerobic activity (SMA: 2.34 mMCH4/hg VSS) and aerobic activity (SOUR: 2.21 mMO2/hg VSS). Metabolite analysis results revealed that PCP was sequentially dechlorinated to TCP, DCP, and eventually to MCP. Methanogens were not directly involved in the dechlorination of PCP, but might played a vital role in stabilizing the overall structure of the granule sludge. For Eubacteria, the Shannon Index (2.09 in inoculated granular sludge) increased both in micro-aerobic granular sludge (2.61) and PCP-degradation granular sludge (2.55). However, for Archaea, it decreased from 2.53 to 1.85 and 1.84, respectively. Although the Shannon Index demonstrated slight difference between micro-aerobic granular sludge and PCP-degradation granular sludge, the Principal Component Analysis (PCA) indicated obvious variance of the microbial composition, revealing significant effect of micro-aerobic condition and PCP on microbial community. Furthermore, nucleotide sequencing indicated that the main microorganisms for PCP degradation might be related to Actinobacterium and Sphingomonas. These results provided insights into situ bioremediation of environments contaminated by PCP and had practical implications for the strategies of PCP degradation. PMID:25151236

  16. BacDive--The Bacterial Diversity Metadatabase in 2016.

    PubMed

    Söhngen, Carola; Podstawka, Adam; Bunk, Boyke; Gleim, Dorothea; Vetcininova, Anna; Reimer, Lorenz Christian; Ebeling, Christian; Pendarovski, Cezar; Overmann, Jörg

    2016-01-01

    BacDive-the Bacterial Diversity Metadatabase (http://bacdive.dsmz.de) provides strain-linked information about bacterial and archaeal biodiversity. The range of data encompasses taxonomy, morphology, physiology, sampling and concomitant environmental conditions as well as molecular biology. The majority of data is manually annotated and curated. Currently (with release 9/2015), BacDive covers 53 978 strains. Newly implemented RESTful web services provide instant access to the content in machine-readable XML and JSON format. Besides an overall increase of data content, BacDive offers new data fields and features, e.g. the search for gene names, plasmids or 16S rRNA in the advanced search, as well as improved linkage of entries to external life science web resources. PMID:26424852

  17. 29 CFR Appendix B to Subpart T to... - Guidelines for Scientific Diving

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 5 2010-07-01 2010-07-01 false Guidelines for Scientific Diving B Appendix B to Subpart T... ADMINISTRATION, DEPARTMENT OF LABOR OCCUPATIONAL SAFETY AND HEALTH STANDARDS Commercial Diving Operations Pt. 1910, Subpt. T, App. B Appendix B to Subpart T to Part 1910—Guidelines for Scientific Diving...

  18. 29 CFR Appendix B to Subpart Y of... - Guidelines for Scientific Diving

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 8 2011-07-01 2011-07-01 false Guidelines for Scientific Diving B Appendix B to Subpart Y... ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving Pt. 1926, Subpt. Y, App. B Appendix B to Subpart Y of Part 1926—Guidelines for Scientific Diving Note:...

  19. 29 CFR Appendix B to Subpart T to... - Guidelines for Scientific Diving

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 5 2011-07-01 2011-07-01 false Guidelines for Scientific Diving B Appendix B to Subpart T... ADMINISTRATION, DEPARTMENT OF LABOR OCCUPATIONAL SAFETY AND HEALTH STANDARDS Commercial Diving Operations Pt. 1910, Subpt. T, App. B Appendix B to Subpart T to Part 1910—Guidelines for Scientific Diving...

  20. 29 CFR Appendix B to Subpart Y of... - Guidelines for Scientific Diving

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Guidelines for Scientific Diving B Appendix B to Subpart Y... ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Diving Pt. 1926, Subpt. Y, App. B Appendix B to Subpart Y of Part 1926—Guidelines for Scientific Diving Note:...

  1. Dolphin lung collapse and intramuscular circulation during free diving: evidence from nitrogen washout.

    PubMed

    Ridgway, S H; Howard, R

    1979-12-01

    Intramuscular nitrogen tensions in Tursiops truncatus after a schedule of repetitive ocean dives suggest a lung collapse depth of about 70 meters and suggest that intramuscular circulation is maintained during unrestrained diving in the open ocean. Therefore, the bottle-nosed dolphin is not protected by lung collapse from the decompression hazards of dives to depths shallower than 70 meters. PMID:505001

  2. Investigation of the potential for vascular bubble formation in a repetitively diving dolphin.

    PubMed

    Houser, D S; Dankiewicz-Talmadge, L A; Stockard, T K; Ponganis, P J

    2010-01-01

    The production of venous gas emboli (VGE) resulting from altered dive behavior is postulated as contributing to the stranding of beaked whales exposed to mid-frequency active sonar. To test whether nitrogen gas uptake during repetitive breath-hold diving is sufficient for asymptomatic VGE formation in odontocetes, a bottlenose dolphin (Tursiops truncatus Montagu) was trained to perform 10-12 serial dives with 60 s surface intervals to depths of 30, 50, 70 or 100 m. The dolphin remained at the bottom depth for 90 s on each dive. Doppler and/or two-dimensional imaging ultrasound did not detect VGE in the portal and brachiocephalic veins following a dive series. Van Slyke analyses of serial, post-dive blood samples drawn from the fluke yielded blood nitrogen partial pressure (P(N(2))) values that were negligibly different from control samples. Mean heart rate (HR; +/-1 s.d.) recorded during diving was 50+/-3 beats min(-1) and was not significantly different between the 50, 70 and 100 m dive sessions. The absence of VGE and elevated blood P(N(2)) during post-dive periods do not support the hypothesis that N(2) supersaturation during repetitive dives contributes to VGE formation in the dolphin. The diving HR pattern and the presumed rapid N(2) washout during the surface-interval tachycardia probably minimized N(2) accumulation in the blood during dive sessions. PMID:20008362

  3. 75 FR 14493 - Safety Zone; Dive Platform, Pago Pago Harbor, American Samoa

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-26

    ...; Dive Platform, Pago Pago Harbor, American Samoa in the Federal Register (75 FR 5907). We received no... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Dive Platform, Pago Pago Harbor, American... temporary safety zone around the USNS Sioux or M/V EL LOBO GRANDE II dive platform and the 332-foot...

  4. Magnitude and rate of accommodation in diving and nondiving birds.

    PubMed

    Sivak, J G; Hildebrand, T; Lebert, C

    1985-01-01

    Accommodation was measured in a variety of waterfowl by projecting parallel low power helium-neon laser beams through the pupils of excised eyes placed in saline. The posterior globe was removed, allowing the beams, refracted only by the lens, to focus well behind the eye. Electrical stimulation of the ciliary muscle results in accommodative movement of the focal point toward the eye. Study of video recordings show that diving ducks (Mergus cucullatus and Bucephala clangala) can accommodate the 70-80 D needed to focus light on the retina when the eye is in water. Diving and nondiving species are compared in amount and rate of accommodation. PMID:4049742

  5. Provisional Crown Dislodgement during Scuba Diving: A Case of Barotrauma

    PubMed Central

    Gulve, Meenal Nitin; Gulve, Nitin Dilip

    2013-01-01

    Changes in ambient pressure, for example, during flying, diving, or hyperbaric oxygen therapy, can lead to barotrauma. Although it may seem that this issue was neglected in dental education and research in recent decades, familiarity with and understanding of these facts may be of importance for dental practitioners. We report the case of a patient who experienced barotrauma involving dislodgement of a provisional crown during scuba diving. Patients who are exposed to pressure changes as a part of their jobs or hobbies and their dentists should know the causes of barotrauma. In addition, the clinician must be aware of the possible influence of pressure changes on the retention of dental components. PMID:23984113

  6. Methods of deep dives in whole ice cover conditions

    NASA Astrophysics Data System (ADS)

    Sagalevich, A. M.

    2016-05-01

    The essence of methodological and engineering questions solved during the preparation and implementation of historic dives of the manned submersibles Mir-1 and Mir-2, allowing humans to see the bottom of the North Pole at a depth of 4300 m, are described together with innovative developments in underwater navigation, as well as the Mir's propulsion, ballast, and other systems that ensured the safety of the dives. These innovative methods have opened up the Arctic's underice space for scientific research and practical exploration for minerals with the direct participation of scientists and specialists.

  7. Provisional Crown Dislodgement during Scuba Diving: A Case of Barotrauma.

    PubMed

    Gulve, Meenal Nitin; Gulve, Nitin Dilip

    2013-01-01

    Changes in ambient pressure, for example, during flying, diving, or hyperbaric oxygen therapy, can lead to barotrauma. Although it may seem that this issue was neglected in dental education and research in recent decades, familiarity with and understanding of these facts may be of importance for dental practitioners. We report the case of a patient who experienced barotrauma involving dislodgement of a provisional crown during scuba diving. Patients who are exposed to pressure changes as a part of their jobs or hobbies and their dentists should know the causes of barotrauma. In addition, the clinician must be aware of the possible influence of pressure changes on the retention of dental components. PMID:23984113

  8. Simulated human diving and heart rate: making the most of the diving response as a laboratory exercise.

    PubMed

    Hiebert, Sara M; Burch, Elliot

    2003-12-01

    Laboratory exercises in which students examine the human diving response are widely used in high school and college biology courses despite the experience of some instructors that the response is unreliably produced in the classroom. Our experience with this exercise demonstrates that the bradycardia associated with the diving response is a robust effect that can easily be measured by students without any sophisticated measurement technology. We discuss measures that maximize the success of the exercise by reducing individual variation, designing experiments that are minimally affected by change in the response over time, collecting data in appropriate time increments, and applying the most powerful statistical analysis. Emphasis is placed on pedagogical opportunities for using this exercise to teach general principles of physiology, experimental design, and data analysis. Data collected by students, background information for instructors, a discussion of the relevance of the diving reflex to humans, suggestions for additional experiments, and thought questions with sample answers are included. PMID:12928322

  9. Effect of diving and diving hoods on the bacterial flora of the external ear canal and skin.

    PubMed Central

    Brook, I; Coolbaugh, J C; Williscroft, R G

    1982-01-01

    The bacterial flora of the external ear canals and posterior auricular skin surfaces were investigated in a group of 26 divers after 25 dry-suit dives in harbor water and 20 dry-suit dives in clear test tank test. A control group of 16 divers wore rubber hoods 19 times for a similar period (25 to 30 min) but did not dive. The protective effect of 2% acetic acid was tested by instilling it in the left ear of 14 divers and 8 nondivers. Staphylococcus epidermidis, Propionibacterium acnes, alpha-hemolytic streptococci, and enteric gram-negative rods were the predominant isolates from skin and ear samples. After the divers dove or after they wore hoods without going in the water, there was a substantial increase in the number of these organisms on the skin (46.9%) or in the external ears (43.8%) of the divers. However, an increase in the bacterial counts in the external ear canals occurred in only 13.6% of the individuals treated prophylactically with acetic acid drops. Although no gram-negative rods were recovered from the skin or external ear canals of divers in clear tank water, 23 strains were isolated after the dives in harbor water. Identical gram-negative isolates also were recovered from the harbor water. Gram-negative organisms also were recovered from three newly acquired skin lacerations, where they persisted for at least 24 h. Our data show the acquisition of gram-negative rods when dives were made in polluted water. The data also demonstrate the increase in bacterial counts that occurs when rubber diving rods are worn (in or out of water) and that this increase can be controlled by pretreatment of ears with acetic acid. PMID:7096559

  10. The cardiovascular and endocrine responses to voluntary and forced diving in trained and untrained rats

    PubMed Central

    DiNovo, Karyn. M.; Connolly, Tiffanny M.

    2010-01-01

    The mammalian diving response, consisting of apnea, bradycardia, and increased total peripheral resistance, can be modified by conscious awareness, fear, and anticipation. We wondered whether swim and dive training in rats would 1) affect the magnitude of the cardiovascular responses during voluntary and forced diving, and 2) whether this training would reduce or eliminate any stress due to diving. Results indicate Sprague-Dawley rats have a substantial diving response. Immediately upon submersion, heart rate (HR) decreased by 78%, from 453 ± 12 to 101 ± 8 beats per minute (bpm), and mean arterial pressure (MAP) decreased 25%, from 143 ± 1 to 107 ± 5 mmHg. Approximately 4.5 s after submergence, MAP had increased to a maximum 174 ± 3 mmHg. Blood corticosterone levels indicate trained rats find diving no more stressful than being held by a human, while untrained rats find swimming and diving very stressful. Forced diving is stressful to both trained and untrained rats. The magnitude of bradycardia was similar during both voluntary and forced diving, while the increase in MAP was greater during forced diving. The diving response of laboratory rats, therefore, appears to be dissimilar from that of other animals, as most birds and mammals show intensification of diving bradycardia during forced diving compared with voluntary diving. Rats may exhibit an accentuated antagonism between the parasympathetic and sympathetic branches of the autonomic nervous system, such that in the autonomic control of HR, parasympathetic activity overpowers sympathetic activity. Additionally, laboratory rats may lack the ability to modify the degree of parasympathetic outflow to the heart during an intense cardiorespiratory response (i.e., the diving response). PMID:19923359

  11. Effect of repetitive SCUBA diving on humoral markers of endothelial and central nervous system integrity.

    PubMed

    Bilopavlovic, Nada; Marinovic, Jasna; Ljubkovic, Marko; Obad, Ante; Zanchi, Jaksa; Pollock, Neal W; Denoble, Petar; Dujic, Zeljko

    2013-07-01

    During SCUBA diving decompression, there is a significant gas bubble production in systemic veins, with rather frequent bubble crossover to arterial side even in asymptomatic divers. The aim of the current study was to investigate potential changes in humoral markers of endothelial and brain damage (endothelin-1, neuron-specific enolase and S-100β) after repetitive SCUBA diving with concomitant assessment of venous gas bubble production and subsequent arterialization. Sixteen male divers performed four open-water no-decompression dives to 18 msw (meters of sea water) lasting 49 min in consecutive days during which they performed moderate-level exercise. Before and after dives 1 and 4 blood was drawn, and bubble production and potential arterialization were echocardiographically evaluated. In addition, a control dive to 5 msw was performed with same duration, water temperature and exercise load. SCUBA diving to 18 msw caused significant bubble production with arterializations in six divers after dive 1 and in four divers after dive 4. Blood levels of endothelin-1 and neuron-specific enolase did not change after diving, but levels of S-100β were significantly elevated after both dives to 18 msw and a control dive. Creatine kinase activity following a control dive was also significantly increased. Although serum S-100β levels were increased after diving, concomitant increase of creatine kinase during control, almost bubble-free, dive suggests the extracranial release of S-100β, most likely from skeletal muscles. Therefore, despite the significant bubble production and sporadic arterialization after open-water dives to 18 msw, the current study found no signs of damage to neurons or the blood-brain barrier. PMID:23400567

  12. Aerobic and anaerobic cellulase production by Cellulomonas uda.

    PubMed

    Poulsen, Henrik Vestergaard; Willink, Fillip Wolfgang; Ingvorsen, Kjeld

    2016-10-01

    Cellulomonas uda (DSM 20108/ATCC 21399) is one of the few described cellulolytic facultative anaerobes. Based on these characteristics, we initiated a physiological study of C. uda with the aim to exploit it for cellulase production in simple bioreactors with no or sporadic aeration. Growth, cellulase activity and fermentation product formation were evaluated in different media under both aerobic and anaerobic conditions and in experiments where C. uda was exposed to alternating aerobic/anaerobic growth conditions. Here we show that C. uda behaves as a true facultative anaerobe when cultivated on soluble substrates such as glucose and cellobiose, but for reasons unknown cellulase activity is only induced under aerobic conditions on insoluble cellulosic substrates and not under anaerobic conditions. These findings enhance knowledge on the limited number of described facultative cellulolytic anaerobes, and in addition it greatly limits the utility of C. uda as an 'easy to handle' cellulase producer with low aeration demands. PMID:27154570

  13. Aerobic exercise increases peripheral and hepatic insulin sensitivity in sedentary adolescents

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Data are limited on the effects of controlled aerobic exercise programs (without weight loss) on insulin sensitivity and glucose metabolism in children and adolescents. To determine whether a controlled aerobic exercise program (without weight loss) improves peripheral and hepatic insulin sensitivi...

  14. Perceptions amongst Tasmanian recreational scuba divers of the value of a diving medical.

    PubMed

    Baines, Carol

    2013-12-01

    An online survey was offered to recreational divers in Tasmania to ascertain if they have an understanding of how pressure affects their health and if they considered an annual dive medical necessary. A total of 98 recreational divers completed the survey, five of these had never had a dive medical while 74 felt that if they passed their dive medical they do not have any potential illness. Sixty five saw the dive medical as a comprehensive health check. This project provided an insight to Tasmanian recreational divers' understanding of and attitude towards the value of a dive medical. PMID:24510335

  15. A Measurement of "g" Using Alexander's Diving Bell

    ERIC Educational Resources Information Center

    Quiroga, M.; Martinez, S.; Otranto, S.

    2010-01-01

    This paper describes a very simple exercise using an inverted test tube pushed straight down into a column of water to determine the free-fall acceleration "g". The exercise employs the ideal gas law and only involves the measurement of the displacement of the bottom of the "diving bell" and the water level inside the tube with respect to the…

  16. OVERVIEW OF DIVE TRAINER SIMULATOR AT SECOND FLOOR LEVEL SHOWING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    OVERVIEW OF DIVE TRAINER SIMULATOR AT SECOND FLOOR LEVEL SHOWING CONTROL CENTER CAB. VIEW FACING WEST/NORTHWEST - U.S. Naval Base, Pearl Harbor, Ford Island Polaris Missile Lab & U.S. Fleet Ballistic Missile Submarine Training Center, Between Lexington Boulvevard and the sea plane ramps on the southwest side of Ford Island, Pearl City, Honolulu County, HI

  17. OVERVIEW OF DIVE TRAINER SIMULATOR FROM FIRST FLOOR LEVEL SHOWING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    OVERVIEW OF DIVE TRAINER SIMULATOR FROM FIRST FLOOR LEVEL SHOWING HYDRAULIC EQUIPMENT, SUPPORTS AND FOUNDATION BLOCKS. VIEW FACING NORTHEAST - U.S. Naval Base, Pearl Harbor, Ford Island Polaris Missile Lab & U.S. Fleet Ballistic Missile Submarine Training Center, Between Lexington Boulvevard and the sea plane ramps on the southwest side of Ford Island, Pearl City, Honolulu County, HI

  18. Performing CPR on a commercial diver inside the diving bell

    PubMed Central

    Bhutani, Sourabh; Verma, Rohit; Ghosh, Dipak Kumar

    2015-01-01

    CPR in a diving bell is difficult. It is taught by diving companies and training institutes but has not been subjected to the tenets of evidence based medicine. The diving bell lacks space as well as a flat hard surface to lay the patient on and therefore conventional methods of administering CPR are not possible. The diver is hung from a pulley tied to the diver's harness, and the bell flooded with water to reduce pooling of blood. Airway is established using a cervical collar to hyperextend the neck and inserting an appropriate oropharyngeal airway. Cardiac compressions are administered by the bellman using his head or the knee while holding the patient with his arms from behind. The bell can be recovered to surface only when spontaneous breathing and circulation have started. Diving bell offers a unique environment for management of unconscious casualties. Even though the method is at variance with the conventional method of administering CPR, it is the only method possible inside the bell. It is important that the method be scrutinized and refined so as to be more effective and efficacious inside the bell. PMID:26957817

  19. Performing CPR on a commercial diver inside the diving bell.

    PubMed

    Bhutani, Sourabh; Verma, Rohit; Ghosh, Dipak Kumar

    2015-01-01

    CPR in a diving bell is difficult. It is taught by diving companies and training institutes but has not been subjected to the tenets of evidence based medicine. The diving bell lacks space as well as a flat hard surface to lay the patient on and therefore conventional methods of administering CPR are not possible. The diver is hung from a pulley tied to the diver's harness, and the bell flooded with water to reduce pooling of blood. Airway is established using a cervical collar to hyperextend the neck and inserting an appropriate oropharyngeal airway. Cardiac compressions are administered by the bellman using his head or the knee while holding the patient with his arms from behind. The bell can be recovered to surface only when spontaneous breathing and circulation have started. Diving bell offers a unique environment for management of unconscious casualties. Even though the method is at variance with the conventional method of administering CPR, it is the only method possible inside the bell. It is important that the method be scrutinized and refined so as to be more effective and efficacious inside the bell. PMID:26957817

  20. Beginning Skin and Scuba Diving, Physical Education: 5551.69.

    ERIC Educational Resources Information Center

    Roberts, Millie

    This course outline is a guide for teaching the principles and basic fundamentals of beginning skin and scuba diving in grades 7-12. The course format includes lectures, skills practice, films, and tests that focus on mastery of skills and understanding correct usage of skin and scuba equipment. Course content includes the following: (a) history,…

  1. Diving bradycardia of elderly Korean women divers, haenyeo, in cold seawater: a field report.

    PubMed

    Lee, Joo-Young; Lee, Hyo-Hyun; Kim, Siyeon; Jang, Young-Joon; Baek, Yoon-Jeong; Kang, Kwon-Yong

    2016-03-28

    The purpose of the present field study was to explore diving patterns and heart rate of elderly Korean women divers (haenyeo) while breath-hold diving in cold seawater. We hypothesized that the decreasing rate in heart rate of elderly haenyeos during breath-hold diving was greater and total diving time was shorter than those of young haenyeos from previous studies. Nine haenyeos participated in a field study [68 ± 10 yr in age, ranged from 56 to 83 yr] at a seawater temperature of 10 to 13 °C. Average total diving time including surface swimming time between dives was 253 ± 73 min (155-341 min). Total frequency of dives was 97 ± 28 times and they dived 23 ± 8 times per hour. All haenyeos showed diving bradycardia with a decreased rate of 20 ± 8% at the bottom time (101 ± 20 bpm) when compared to surface swimming time (125 ± 16 bpm) in the sea. Older haenyeos among the nine elderly haenyeos had shorter diving time, less diving frequencies, and lower heart rate at work (p<0.05). These reductions imply that haenyeos voluntarily adjust their workload along with advancing age and diminished cardiovascular functions. PMID:26632118

  2. Diving bradycardia of elderly Korean women divers, haenyeo, in cold seawater: a field report

    PubMed Central

    LEE, Joo-Young; LEE, Hyo-Hyun; KIM, Siyeon; JANG, Young-Joon; BAEK, Yoon-Jeong; KANG, Kwon-Yong

    2015-01-01

    The purpose of the present field study was to explore diving patterns and heart rate of elderly Korean women divers (haenyeo) while breath-hold diving in cold seawater. We hypothesized that the decreasing rate in heart rate of elderly haenyeos during breath-hold diving was greater and total diving time was shorter than those of young haenyeos from previous studies. Nine haenyeos participated in a field study [68 ± 10 yr in age, ranged from 56 to 83 yr] at a seawater temperature of 10 to 13 °C. Average total diving time including surface swimming time between dives was 253 ± 73 min (155–341 min). Total frequency of dives was 97 ± 28 times and they dived 23 ± 8 times per hour. All haenyeos showed diving bradycardia with a decreased rate of 20 ± 8% at the bottom time (101 ± 20 bpm) when compared to surface swimming time (125 ± 16 bpm) in the sea. Older haenyeos among the nine elderly haenyeos had shorter diving time, less diving frequencies, and lower heart rate at work (p<0.05). These reductions imply that haenyeos voluntarily adjust their workload along with advancing age and diminished cardiovascular functions. PMID:26632118

  3. Diving behaviour of whale sharks in relation to a predictable food pulse

    PubMed Central

    Graham, Rachel T; Roberts, Callum M; Smart, James C.R

    2005-01-01

    We present diving data for four whale sharks in relation to a predictable food pulse (reef fish spawn) and an analysis of the longest continuous fine-resolution diving record for a planktivorous shark. Fine-resolution pressure data from a recovered pop-up archival satellite tag deployed for 206 days on a whale shark were analysed using the fast Fourier Transform method for frequency domain analysis of time-series. The results demonstrated that a free-ranging whale shark displays ultradian, diel and circa-lunar rhythmicity of diving behaviour. Whale sharks dive to over 979.5 m and can tolerate a temperature range of 26.4 °C. The whale sharks made primarily diurnal deep dives and remained in relatively shallow waters at night. Whale shark diving patterns are influenced by a seasonally predictable food source, with shallower dives made during fish spawning periods. PMID:16849222

  4. A single air dive reduces arterial endothelial function in man.

    PubMed

    Brubakk, A O; Duplancic, D; Valic, Z; Palada, I; Obad, A; Bakovic, D; Wisloff, U; Dujic, Z

    2005-08-01

    During and after decompression from dives, gas bubbles are regularly observed in the right ventricular outflow tract. A number of studies have documented that these bubbles can lead to endothelial dysfunction in the pulmonary artery but no data exist on the effect of diving on arterial endothelial function. The present study investigated if diving or oxygen breathing would influence endothelial arterial function in man. A total of 21 divers participated in this study. Nine healthy experienced male divers with a mean age of 31 +/- 5 years were compressed in a hyperbaric chamber to 280 kPa at a rate of 100 kPa min(-1) breathing air and remaining at pressure for 80 min. The ascent rate during decompression was 9 kPa min(-1) with a 7 min stop at 130 kPa (US Navy procedure). Another group of five experienced male divers (31 +/- 6 years) breathed 60% oxygen (corresponding to the oxygen tension of air at 280 kPa) for 80 min. Before and after exposure, endothelial function was assessed in both groups as flow-mediated dilatation (FMD) by ultrasound in the brachial artery. The results were compared to data obtained from a group of seven healthy individuals of the same age who had never dived. The dive produced few vascular bubbles, but a significant arterial diameter increase from 4.5 +/- 0.7 to 4.8 +/- 0.8 mm (mean +/- s.d.) and a significant reduction of FMD from 9.2 +/- 6.9 to 5.0 +/- 6.7% were observed as an indication of reduced endothelial function. In the group breathing oxygen, arterial diameter increased significantly from 4.4 +/- 0.3 mm to 4.7 +/- 0.3 mm, while FMD showed an insignificant decrease. Oxygen breathing did not decrease nitroglycerine-induced dilatation significantly. In the normal controls the arterial diameter and FMD were 4.1 +/- 0.4 mm and 7.7 +/- 0.2.8%, respectively. This study shows that diving can lead to acute arterial endothelial dysfunction in man and that oxygen breathing will increase arterial diameter after return to breathing air. Further

  5. A single air dive reduces arterial endothelial function in man

    PubMed Central

    Brubakk, AO; Duplancic, D; Valic, Z; Palada, I; Obad, A; Bakovic, D; Wisloff, U; Dujic, Z

    2005-01-01

    During and after decompression from dives, gas bubbles are regularly observed in the right ventricular outflow tract. A number of studies have documented that these bubbles can lead to endothelial dysfunction in the pulmonary artery but no data exist on the effect of diving on arterial endothelial function. The present study investigated if diving or oxygen breathing would influence endothelial arterial function in man. A total of 21 divers participated in this study. Nine healthy experienced male divers with a mean age of 31 ± 5 years were compressed in a hyperbaric chamber to 280 kPa at a rate of 100 kPa min−1 breathing air and remaining at pressure for 80 min. The ascent rate during decompression was 9 kPa min−1 with a 7 min stop at 130 kPa (US Navy procedure). Another group of five experienced male divers (31 ± 6 years) breathed 60% oxygen (corresponding to the oxygen tension of air at 280 kPa) for 80 min. Before and after exposure, endothelial function was assessed in both groups as flow-mediated dilatation (FMD) by ultrasound in the brachial artery. The results were compared to data obtained from a group of seven healthy individuals of the same age who had never dived. The dive produced few vascular bubbles, but a significant arterial diameter increase from 4.5 ± 0.7 to 4.8 ± 0.8 mm (mean ± s.d.) and a significant reduction of FMD from 9.2 ± 6.9 to 5.0 ± 6.7% were observed as an indication of reduced endothelial function. In the group breathing oxygen, arterial diameter increased significantly from 4.4 ± 0.3 mm to 4.7 ± 0.3 mm, while FMD showed an insignificant decrease. Oxygen breathing did not decrease nitroglycerine-induced dilatation significantly. In the normal controls the arterial diameter and FMD were 4.1 ± 0.4 mm and 7.7 ± 0.2.8%, respectively. This study shows that diving can lead to acute arterial endothelial dysfunction in man and that oxygen breathing will increase arterial diameter after return to breathing air. Further studies

  6. Comparison between the antioxidant status of terrestrial and diving mammals.

    PubMed

    Wilhelm Filho, D; Sell, F; Ribeiro, L; Ghislandi, M; Carrasquedo, F; Fraga, C G; Wallauer, J P; Simões-Lopes, P C; Uhart, M M

    2002-11-01

    Many diving mammals are known for their ability to deal with nitrogen supersaturation and to tolerate apnea for extended periods. They are all characterized by high oxygen-carrying capacity in blood together with high oxygen storage in their muscle mass due to large myoglobin concentrations. The above properties theoretically also imply a high tissue antioxidant defenses (AD) to counteract reactive oxygen species (ROS) generation associated with the rapid transition from apnea to reoxygenation. Different enzymatic (superoxide dismutase, catalase, glutathione reductase, glutathione peroxidase, and glutathione S-transferase), and non-enzymatic (levels of glutathione) AD as well as cellular damage (thiobarbituric acid-reactive substances contents, as a measure of lipoperoxidation) were measured in blood samples obtained from anesthetized animals, and also in blood obtained from recently dead diving mammals, and compared to some terrestrial mammals (n=5 in both groups). The results confirmed that diving mammals have, in general, higher antioxidant status compared to non-diving mammals. Apparently, to avoid exposure of tissues to changing high oxygen levels, and therefore to avoid an oxidative stress condition related to antioxidant consumption and increased ROS generation, diving mammals possess constitutive high levels of antioxidants in tissues. These data are in agreement with short-term AD adaptations related to torpor and to animals that experience large daily changes in oxygen consumption. These data are similar to the long-term adaptations of animals that undergo hibernation, estivation, freezing-thawing and dehydration-rehydration processes. In summary, animals that routinely face high changes in oxygen availability and/or consumption seem to show a general strategy to prevent oxidative damage by having either appropriate high constitutive AD and/or the ability to undergo arrested states, where depressed metabolic rates minimize the oxidative challenge. PMID

  7. Pulmonary mechanical function and diffusion capacity after deep saturation dives.

    PubMed Central

    Thorsen, E; Segadal, K; Myrseth, E; Påsche, A; Gulsvik, A

    1990-01-01

    To assess the effects of deep saturation dives on pulmonary function, static and dynamic lung volumes, transfer factor for carbon monoxide (T1CO), delta-N2, and closing volume (CV) were measured before and after eight saturation dives to pressures of 3.1-4.6 MPa. The atmospheres were helium-oxygen mixtures with partial pressures of oxygen of 40-60 kPa. The durations of the dives were 14-30 days. Mean rate of decompression was 10.5-13.5 kPa/hour. A total of 43 divers were examined, six of whom took part in two dives, the others in one only. Dynamic lung volumes did not change significantly but total lung capacity (TLC) increased significantly by 4.3% and residual volume (RV) by 14.8% (p less than 0.05). CV was increased by 16.7% (p less than 0.01). The T1CO was reduced from 13.0 +/- 1.6 to 11.8 +/- 1.7 mmol/min/kPa (p less than 0.01) when corrected to a haemoglobin concentration of 146 g/l. Effective alveolar volume was unchanged. The increase in TLC and decrease in T1CO were correlated (r = -0.574, p less than 0.02). A control examination of 38 of the divers four to six weeks after the dives showed a partial normalisation of the changes. The increase in TLC, RV, and CV, and the decrease in T1CO, could be explained by a loss of pulmonary elastic tissue caused by inflammatory reactions induced by oxygen toxicity or venous gas emboli. PMID:2337532

  8. EPO modulation in a 14-days undersea scuba dive.

    PubMed

    Revelli, L; Vagnoni, S; D'Amore, A; Di Stasio, E; Lombardi, C P; Storti, G; Proietti, R; Balestra, C; Ricerca, B M

    2013-10-01

    Erythropoiesis is affected during deep saturation dives. The mechanism should be related to a downregulation of serum Erythropoietin (s-EPO) concentration or to a toxic effect of the hyperbaric hyperoxia. We evaluated s-EPO and other haematological parameters in 6 scuba divers before, during and after a 14-days guinness saturation dive (8-10 m). Athletes were breathing air at 1.8-2 ATA, under the control of a team of physicians. Serum parameters were measured before diving (T0) and: 7 days (T1), 14 days (T2) after the beginning of the dive and 2 h (T3) and 24 h (T4) after resurfacing. Hgb, and many other haematological parameters did not change whereas Ht, s-EPO, the ratio between s-EPO predicted and that observed and reticulocytes (absolute, percent) declined progressively from T0 to T3. At T4 a significant rise in s-EPO was observed. Hgb did not vary but erythropoiesis seemed to be affected as s-EPO and reticulocyte counts showed. All these changes were statistically significant. The experiment, conducted in realistic conditions of dive length, oxygen concentration and pressure, allows us to formulate some hypotheses about the role of prolonged hyperbarism on erythropoiesis. The s-EPO rise, 24 h after resurfacing, is clearly documented and related to the "Normobaric Oxygen Paradox". This evidence suggests interesting hypotheses for new clinical applications such as modulation of s-EPO production and Hgb content triggered by appropriate O₂ administration in pre-surgical patients or in some anemic disease. PMID:23670359

  9. Diving-flight aerodynamics of a peregrine falcon (Falco peregrinus).

    PubMed

    Ponitz, Benjamin; Schmitz, Anke; Fischer, Dominik; Bleckmann, Horst; Brücker, Christoph

    2014-01-01

    This study investigates the aerodynamics of the falcon Falco peregrinus while diving. During a dive peregrines can reach velocities of more than 320 km h⁻¹. Unfortunately, in freely roaming falcons, these high velocities prohibit a precise determination of flight parameters such as velocity and acceleration as well as body shape and wing contour. Therefore, individual F. peregrinus were trained to dive in front of a vertical dam with a height of 60 m. The presence of a well-defined background allowed us to reconstruct the flight path and the body shape of the falcon during certain flight phases. Flight trajectories were obtained with a stereo high-speed camera system. In addition, body images of the falcon were taken from two perspectives with a high-resolution digital camera. The dam allowed us to match the high-resolution images obtained from the digital camera with the corresponding images taken with the high-speed cameras. Using these data we built a life-size model of F. peregrinus and used it to measure the drag and lift forces in a wind-tunnel. We compared these forces acting on the model with the data obtained from the 3-D flight path trajectory of the diving F. peregrinus. Visualizations of the flow in the wind-tunnel uncovered details of the flow structure around the falcon's body, which suggests local regions with separation of flow. High-resolution pictures of the diving peregrine indicate that feathers pop-up in the equivalent regions, where flow separation in the model falcon occurred. PMID:24505258

  10. Diving-Flight Aerodynamics of a Peregrine Falcon (Falco peregrinus)

    PubMed Central

    Ponitz, Benjamin; Schmitz, Anke; Fischer, Dominik; Bleckmann, Horst; Brücker, Christoph

    2014-01-01

    This study investigates the aerodynamics of the falcon Falco peregrinus while diving. During a dive peregrines can reach velocities of more than 320 km h−1. Unfortunately, in freely roaming falcons, these high velocities prohibit a precise determination of flight parameters such as velocity and acceleration as well as body shape and wing contour. Therefore, individual F. peregrinus were trained to dive in front of a vertical dam with a height of 60 m. The presence of a well-defined background allowed us to reconstruct the flight path and the body shape of the falcon during certain flight phases. Flight trajectories were obtained with a stereo high-speed camera system. In addition, body images of the falcon were taken from two perspectives with a high-resolution digital camera. The dam allowed us to match the high-resolution images obtained from the digital camera with the corresponding images taken with the high-speed cameras. Using these data we built a life-size model of F. peregrinus and used it to measure the drag and lift forces in a wind-tunnel. We compared these forces acting on the model with the data obtained from the 3-D flight path trajectory of the diving F. peregrinus. Visualizations of the flow in the wind-tunnel uncovered details of the flow structure around the falcon’s body, which suggests local regions with separation of flow. High-resolution pictures of the diving peregrine indicate that feathers pop-up in the equivalent regions, where flow separation in the model falcon occurred. PMID:24505258

  11. Swimming: An Introduction to Swimming, Diving, and SCUBA Diving for Blind and Physically Handicapped Individuals. Leisure Pursuit Series.

    ERIC Educational Resources Information Center

    Cylke, Frank Kurt, Ed.

    The annotated guide lists information sources available from the National Library Service for the Blind and Physically Handicapped in print, disc, cassette, and braille formats concerning swimming and diving with special reference to blind swimmers. The guide begins with a brief sketch of a champion swimmer who is also legally blind and an…

  12. Aerobic Capacities of Early College High School Students

    ERIC Educational Resources Information Center

    Loflin, Jerry W.

    2014-01-01

    The Early College High School Initiative (ECHSI) was introduced in 2002. Since 2002, limited data, especially student physical activity data, have been published pertaining to the ECHSI. The purpose of this study was to examine the aerobic capacities of early college students and compare them to state and national averages. Early college students…

  13. Little left in the tank: metabolic scaling in marine teleosts and its implications for aerobic scope

    PubMed Central

    Killen, Shaun S; Costa, Isabel; Brown, Joseph A; Gamperl, A. Kurt

    2006-01-01

    Fish larvae are the world's smallest vertebrates, and their high rates of mortality may be partially owing to a very limited aerobic scope. Unfortunately, however, no complete empirical dataset exists on the relationship between minimal and maximal metabolism (and thus aerobic scope) for any fish species throughout ontogeny, and thus such an association is hard to delineate. We measured standard and maximal metabolism in three marine fish species over their entire life history, and show that while aerobic scope depends greatly on body size and developmental trajectory, it is extremely small during the early life stages (factorial aerobic scope≤1.5). Our findings strongly suggest that limited scope for aerobic activity early in life is likely to constrain physiological function and ultimately impact behaviour and possibly survival. Furthermore, our results have important implications for ecological models that incorporate metabolic scaling, and provide additional evidence against the existence of ‘universal’ scaling exponents. PMID:17164208

  14. What are the differences between aerobic and anaerobic toxic effects of sulfonamides on Escherichia coli?

    PubMed

    Qin, Mengnan; Lin, Zhifen; Wang, Dali; Long, Xi; Zheng, Min; Qiu, Yanling

    2016-01-01

    Bacteria in the environment face the threat of antibiotics. However, most studies investigating the toxicity and toxicity mechanisms of antibiotics have been conducted on microorganisms in aerobic conditions, while studies examining the anaerobic toxicity and toxicity mechanisms of antibiotics are still limited. In this study, we determined the aerobic and anaerobic toxicities of sulfonamides (SAs) on Escherichia coli. Next, a comparison of the aerobic and anaerobic toxicities indicated that the SAs could be divided into three groups: Group I: log(1/EC50-anaerobic)>log(1/EC50-aerobic) (EC50-anaerobic/EC50-aerobic, the median effective concentration under anaerobic/aerobic conditions), Group II: log(1/EC50-anaerobic)≈log(1/EC50-aerobic), and Group III: log(1/EC50-anaerobic)aerobic). Furthermore, this division was not based on the reactive oxygen species (ROS) level or the interaction energy (Ebinding) value, which represents the affinity between SAs and dihydropteroate synthase (dhps) but rather on the total binding energy. Furthermore, SAs with greatly similar structures were categorized into different groups. This deep insight into the difference between aerobic and anaerobic toxicities will benefit environmental science, and the results of this study will serve as a reference for the risk assessment of chemicals in the environment. PMID:26748048

  15. The contribution of nasal receptors to the cardiac response to diving in restrained and unrestrained redhead ducks (Aythya americana).

    PubMed

    Furilla, R A; Jones, D R

    1986-03-01

    In restrained redhead ducks, forced submergence caused heart rate to fall from 100 +/- 3 beats min-1 (mean +/- S.E.M., N = 12) to a stable underwater rate of 35 +/- 4 beats min-1 (N = 12) within 5 s after submergence. Bradycardia was unaffected by breathing oxygen before a dive, but was virtually eliminated by local anaesthesia of the narial region. In contrast, in a dabbling duck (Anas platyrhynchos) bradycardia in short dives was eliminated by breathing oxygen before a dive. In unrestrained diving, on a man-made pond, heart rate in redheads diving voluntarily (y) was related to pre-dive heart rate (x) by the equation y = 76 + 0.29 +/- 0.05x +/- 17 (r2 = 0.71). Chasing, to induce submergence, had variable effects on this relationship. Local anaesthesia of the narial region inhibited voluntary diving but heart rates in chase-induced dives after nasal blockade were significantly higher, by 10-30%, than those obtained from untreated ducks in chase-induced dives. Breathing oxygen before voluntary dives had no apparent effect on heart rate after 2-5 s submergence. Voluntary head submersion by dabbling ducks caused no change in heart rate. We conclude that nasal receptors make only a minor contribution to cardiac responses in unrestrained dives, compared with forced dives, in diving ducks. Furthermore, these results show that little can be learned about cardiac responses in free diving ducks from studies of forced dives in dabblers or divers. PMID:3958677

  16. Concentration of circulating autoantibodies against HSP 60 is lowered through diving when compared to non-diving rats

    PubMed Central

    Havnes, Marianne B.; Ahlén, Catrine; Brubakk, Alf O.; Iversen, Ole-Jan

    2012-01-01

    Objective Skin and ear infections, primarily caused by Pseudomonas aeruginosa (P. aeruginosa), are recurrent problems for saturation divers, whereas infections caused by P. aeruginosa are seldom observed in healthy people outside saturation chambers. Cystic fibrosis (CF) patients suffer from pulmonary infections by P. aeruginosa, and it has been demonstrated that CF patients have high levels of autoantibodies against Heat shock protein 60 (HSP60) compared to controls, probably due to cross-reacting antibodies induced by P. aeruginosa. The present study investigated whether rats immunised with P. aeruginosa produced autoantibodies against their own HSP60 and whether diving influenced the level of circulating anti-HSP60 antibodies. Methods A total of 24 rats were randomly assigned to one of three groups (‘immunised’, ‘dived’ and ‘immunised and dived’). The rats in group 1 and 3 were immunised with the bacteria P. aeruginosa, every other week. Groups 2 and 3 were exposed to simulated air dives to 400 kPa (4 ata) with 45 min bottom time, every week for 7 weeks. Immediately after surfacing, the rats were anaesthetised and blood was collected from the saphenous vein. The amount of anti-HSP60 rat antibodies in the serum was analysed by enzyme linked immunosorbent assay. Results The immunised rats (group 1) showed a significant increase in the level of autoantibodies against HSP60, whereas no autoantibodies were detected in the dived rats (group 2). The rats both immunised and dived (group 3) show no significant increase in circulating autoantibodies against HSP60. A possible explanation may be that HSP60 is expressed during diving and that cross-reacting antibodies are bound. PMID:23990832

  17. Fatal respiratory failure during a "technical" rebreather dive at extreme pressure.

    PubMed

    Mitchell, Simon J; Cronjé, Frans J; Meintjes, W A Jack; Britz, Hermie C

    2007-02-01

    A diving fatality at the extreme depth of 264 m fresh water is described. The diver was equipped with an underwater video camera which recorded events leading to his death. These events corroborated predictions about respiratory complications at extreme pressure made by early researchers. Review of the video and relevant literature resulted in the following physiological interpretation: an increase in respired gas density during descent caused a progressive increase in resistance to flow in both the airways and the breathing circuit. Initially, this was associated with a shift to ventilation at higher lung volumes, a relative degree of hypoventilation, and mild permissive hypercapnia. The promotion of turbulent airway flow by increasing gas density resulted in effort-independent expiratory flow at lower flow rates than usual. The consequent inability to match ventilation to the demands of physical work at the bottom precipitated a spiraling crisis of dyspnea, increasing PaCO2, and wasted respiratory effort, thus producing more CO2. Extreme hypercapnia eventually led to unconsciousness. This tragic case provides a timely and salient lesson to a growing population of deep "technical" divers that there are physiological limitations that must be understood and considered when planning extreme dives. PMID:17310877

  18. Chemoreceptor control of heart rate and behaviour during diving in the tufted duck (Aythya fuligula).

    PubMed

    Butler, P J; Stephenson, R

    1988-03-01

    1. The role of chemoreceptors in the control of heart rate and behaviour during diving activity in the tufted duck was investigated in two ways. In a closed-loop experiment, ducks were exposed to ambient gas mixtures of varied composition during diving activity in an indoor tank. Characteristics of diving behaviour, heart rate and deep body temperature were monitored under hypoxic, hyperoxic and hypercapnic conditions and compared with those in air. Secondly, in an open-loop experiment the role of the carotid body (CB) chemoreceptors in the control of the responses to altered inspired gas composition and in the cardiac responses to extended and enclosed dives (Stephenson, Butler & Woakes, 1986) was investigated by chronic bilateral denervation of these receptors. 2. Heart rate during submersion was unaffected by inspired gas composition in control (data from intact and sham-operated ducks combined) and CB-denervated ducks, though diving behaviour was significantly modified in both groups of animals in response to altered inspired gas composition. Hypoxia and hypercapnia resulted in an increase in the proportion of total diving time spent breathing at the surface. The main effect of hypoxia (9-10% O2) was to reduce dive duration in control ducks and this effect was almost completely abolished after CB denervation. Hypercapnia (5-6% CO2) reduced dive duration less markedly than hypoxia but it greatly increased the duration of the inter-dive interval, effects which were not significantly influenced by CB denervation. Hyperoxia (40-45% O2) had very little effect on either behaviour or heart rate during diving, although deep body temperature was significantly elevated in this gas mixture during diving activity. There was also a less marked, but nevertheless significant, apparent hyperthermia during diving activity in air on an indoor tank but not on an outdoor pond. Conversely, there was a significant apparent hypothermia during diving activity under hypoxic conditions

  19. The Transition from Aerobic to Anaerobic Metabolism.

    ERIC Educational Resources Information Center

    Skinner, James S.; McLellan, Thomas H.

    1980-01-01

    The transition from aerobic to anaerobic metabolism is discussed. More research is needed on different kinds of athletes and athletic activities and how they may affect aerobic and anaerobic metabolisms. (CJ)

  20. Habitat-Mediated Dive Behavior in Free-Ranging Grey Seals

    PubMed Central

    Jessopp, Mark; Cronin, Michelle; Hart, Tom

    2013-01-01

    Understanding the links between foraging behaviour and habitat use of key species is essential to addressing fundamental questions about trophic interactions and ecosystem functioning. Eight female grey seals (Halichoerus grypus) were equipped with time-depth recorders linked to Fastloc GPS tags following the annual moult in southwest Ireland. Individual dives were coupled with environmental correlates to investigate the habitat use and dive behaviour of free-ranging seals. Dives were characterised as either pelagic, benthic, or shallow (where errors in location and charted water depth made differentiating between pelagic and benthic dives unreliable). Sixty-nine percent of dives occurring in water >50 m were benthic. Pelagic dives were more common at night than during the day. Seals performed more pelagic dives over fine sediments (mud/sand), and more benthic dives when foraging over more three-dimensionally complex rock substrates. We used Markov chain analysis to determine the probability of transiting between dive states. A low probability of repeat pelagic dives suggests that pelagic prey were encountered en route to the seabed. This approach could be applied to make more accurate predictions of habitat use in data-poor areas, and investigate contentious issues such as resource overlap and competition between top predators and fisheries, essential for the effective conservation of these key marine species. PMID:23667663

  1. Investigating annual diving behaviour by hooded seals (Cystophora cristata) within the Northwest Atlantic Ocean.

    PubMed

    Andersen, Julie M; Skern-Mauritzen, Mette; Boehme, Lars; Wiersma, Yolanda F; Rosing-Asvid, Aqqalu; Hammill, Mike O; Stenson, Garry B

    2013-01-01

    With the exception of relatively brief periods when they reproduce and moult, hooded seals, Cystophora cristata, spend most of the year in the open ocean where they undergo feeding migrations to either recover or prepare for the next fasting period. Valuable insights into habitat use and diving behaviour during these periods have been obtained by attaching Satellite Relay Data Loggers (SRDLs) to 51 Northwest (NW) Atlantic hooded seals (33 females and 18 males) during ice-bound fasting periods (2004-2008). Using General Additive Models (GAMs) we describe habitat use in terms of First Passage Time (FPT) and analyse how bathymetry, seasonality and FPT influence the hooded seals' diving behaviour described by maximum dive depth, dive duration and surface duration. Adult NW Atlantic hooded seals exhibit a change in diving activity in areas where they spend >20 h by increasing maximum dive depth, dive duration and surface duration, indicating a restricted search behaviour. We found that male and female hooded seals are spatially segregated and that diving behaviour varies between sexes in relation to habitat properties and seasonality. Migration periods are described by increased dive duration for both sexes with a peak in May, October and January. Males demonstrated an increase in dive depth and dive duration towards May (post-breeding/pre-moult) and August-October (post-moult/pre-breeding) but did not show any pronounced increase in surface duration. Females dived deepest and had the highest surface duration between December and January (post-moult/pre-breeding). Our results suggest that the smaller females may have a greater need to recover from dives than that of the larger males. Horizontal segregation could have evolved as a result of a resource partitioning strategy to avoid sexual competition or that the energy requirements of males and females are different due to different energy expenditure during fasting periods. PMID:24282541

  2. Argon used as dry suit insulation gas for cold-water diving

    PubMed Central

    2013-01-01

    Background Cold-water diving requires good thermal insulation because hypothermia is a serious risk. Water conducts heat more efficiently compared to air. To stay warm during a dive, the choice of thermal protection should be based on physical activity, the temperature of the water, and the duration of exposure. A dry suit, a diving suit filled with gas, is the most common diving suit in cold water. Air is the traditional dry suit inflation gas, whereas the thermal conductivity of argon is approximately 32% lower compared to that of air. This study evaluates the benefits of argon, compared to air, as a thermal insulation gas for a dry suit during a 1-h cold-water dive by divers of the Royal Netherlands Navy. Methods Seven male Special Forces divers made (in total) 19 dives in a diving basin with water at 13°C at a depth of 3 m for 1 h in upright position. A rubber dry suit and woollen undergarment were used with either argon (n = 13) or air (n = 6) (blinded to the divers) as suit inflation gas. Core temperature was measured with a radio pill during the dive. Before, halfway, and after the dive, subjective thermal comfort was recorded using a thermal comfort score. Results No diver had to abort the test due to cold. No differences in core temperature and thermal comfort score were found between the two groups. Core temperature remained unchanged during the dives. Thermal comfort score showed a significant decrease in both groups after a 60-min dive compared to baseline. Conclusions In these tests the combination of the dry suit and undergarment was sufficient to maintain core temperature and thermal comfort for a dive of 1 h in water at 13°C. The use of argon as a suit inflation gas had no added value for thermal insulation compared to air for these dives. PMID:24438580

  3. The effects of acute oral antioxidants on diving-induced alterations in human cardiovascular function

    PubMed Central

    Obad, Ante; Palada, Ivan; Valic, Zoran; Ivančev, Vladimir; Baković, Darija; Wisløff, Ulrik; Brubakk, Alf O; Dujić, Željko

    2007-01-01

    Diving-induced acute alterations in cardiovascular function such as arterial endothelial dysfunction, increased pulmonary artery pressure (PAP) and reduced heart function have been recently reported. We tested the effects of acute antioxidants on arterial endothelial function, PAP and heart function before and after a field dive. Vitamins C (2 g) and E (400 IU) were given to subjects 2 h before a second dive (protocol 1) and in a placebo-controlled crossover study design (protocol 2). Seven experienced divers performed open sea dives to 30 msw with standard decompression in a non-randomized protocol, and six of them participated in a randomized trial. Before and after the dives ventricular volumes and function and pulmonary and brachial artery function were assessed by ultrasound. The control dive resulted in a significant reduction in flow-mediated dilatation (FMD) and heart function with increased mean PAP. Twenty-four hours after the control dive FMD was still reduced 37% below baseline (8.1 versus 5.1%, P = 0.005), while right ventricle ejection fraction (RV-EF), left ventricle EF and endocardial fractional shortening were reduced much less (∼2–3%). At the same time RV end-systolic volume was increased by 9% and mean PAP by 5%. Acute antioxidants significantly attenuated only the reduction in FMD post-dive (P < 0.001), while changes in pulmonary artery and heart function were unaffected by antioxidant ingestion. These findings were confirmed by repeating the experiments in a randomized study design. FMD returned to baseline values 72 h after the dive with pre-dive placebo, whereas for most cardiovascular parameters this occurred earlier (24–48 h). Right ventricular dysfunction and increased PAP lasted longer. Acute antioxidants attenuated arterial endothelial dysfunction after diving, while reduction in heart and pulmonary artery function were unchanged. Cardiovascular changes after diving are not fully reversed up to 3 days after a dive, suggesting

  4. Investigating Annual Diving Behaviour by Hooded Seals (Cystophora cristata) within the Northwest Atlantic Ocean

    PubMed Central

    Andersen, Julie M.; Skern-Mauritzen, Mette; Boehme, Lars; Wiersma, Yolanda F.; Rosing-Asvid, Aqqalu; Hammill, Mike O.; Stenson, Garry B.

    2013-01-01

    With the exception of relatively brief periods when they reproduce and moult, hooded seals, Cystophora cristata, spend most of the year in the open ocean where they undergo feeding migrations to either recover or prepare for the next fasting period. Valuable insights into habitat use and diving behaviour during these periods have been obtained by attaching Satellite Relay Data Loggers (SRDLs) to 51 Northwest (NW) Atlantic hooded seals (33 females and 18 males) during ice-bound fasting periods (2004−2008). Using General Additive Models (GAMs) we describe habitat use in terms of First Passage Time (FPT) and analyse how bathymetry, seasonality and FPT influence the hooded seals’ diving behaviour described by maximum dive depth, dive duration and surface duration. Adult NW Atlantic hooded seals exhibit a change in diving activity in areas where they spend >20 h by increasing maximum dive depth, dive duration and surface duration, indicating a restricted search behaviour. We found that male and female hooded seals are spatially segregated and that diving behaviour varies between sexes in relation to habitat properties and seasonality. Migration periods are described by increased dive duration for both sexes with a peak in May, October and January. Males demonstrated an increase in dive depth and dive duration towards May (post-breeding/pre-moult) and August–October (post-moult/pre-breeding) but did not show any pronounced increase in surface duration. Females dived deepest and had the highest surface duration between December and January (post-moult/pre-breeding). Our results suggest that the smaller females may have a greater need to recover from dives than that of the larger males. Horizontal segregation could have evolved as a result of a resource partitioning strategy to avoid sexual competition or that the energy requirements of males and females are different due to different energy expenditure during fasting periods. PMID:24282541

  5. Surfacers change their dive tactics depending on the aim of the dive: evidence from simultaneous measurements of breaths and energy expenditure.

    PubMed

    Okuyama, Junichi; Tabata, Runa; Nakajima, Kana; Arai, Nobuaki; Kobayashi, Masato; Kagawa, Shiro

    2014-11-22

    Air-breathing divers are assumed to have evolved to apportion their time between surface and underwater periods to maximize the benefit gained from diving activities. However, whether they change their time allocation depending on the aim of the dive is still unknown. This may be particularly crucial for 'surfacers' because they dive for various purposes in addition to foraging. In this study, we counted breath events at the surface and estimated oxygen consumption during resting, foraging and other dives in 11 green turtles (Chelonia mydas) in the wild. Breath events were counted by a head-mounted acceleration logger or direct observation based on an animal-borne video logger, and oxygen consumption was estimated by measuring overall dynamic body acceleration. Our results indicate that green turtles maximized their submerged time, following this with five to seven breaths to replenish oxygen for resting dives. However, they changed their dive tactic during foraging and other dives; they surfaced without depleting their estimated stores of oxygen, followed by only a few breaths for effective foraging and locomotion. These dichotomous surfacing tactics would be the result of behavioural modifications by turtles depending on the aim of each dive. PMID:25297856

  6. Surfacers change their dive tactics depending on the aim of the dive: evidence from simultaneous measurements of breaths and energy expenditure

    PubMed Central

    Okuyama, Junichi; Tabata, Runa; Nakajima, Kana; Arai, Nobuaki; Kobayashi, Masato; Kagawa, Shiro

    2014-01-01

    Air-breathing divers are assumed to have evolved to apportion their time between surface and underwater periods to maximize the benefit gained from diving activities. However, whether they change their time allocation depending on the aim of the dive is still unknown. This may be particularly crucial for ‘surfacers’ because they dive for various purposes in addition to foraging. In this study, we counted breath events at the surface and estimated oxygen consumption during resting, foraging and other dives in 11 green turtles (Chelonia mydas) in the wild. Breath events were counted by a head-mounted acceleration logger or direct observation based on an animal-borne video logger, and oxygen consumption was estimated by measuring overall dynamic body acceleration. Our results indicate that green turtles maximized their submerged time, following this with five to seven breaths to replenish oxygen for resting dives. However, they changed their dive tactic during foraging and other dives; they surfaced without depleting their estimated stores of oxygen, followed by only a few breaths for effective foraging and locomotion. These dichotomous surfacing tactics would be the result of behavioural modifications by turtles depending on the aim of each dive. PMID:25297856

  7. 29 CFR Appendix C to Subpart T to... - Alternative Conditions Under § 1910.401(a)(3) for Recreational Diving Instructors and Diving...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 5 2012-07-01 2012-07-01 false Alternative Conditions Under § 1910.401(a)(3) for Recreational Diving Instructors and Diving Guides (Mandatory) C Appendix C to Subpart T to Part 1910 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR OCCUPATIONAL SAFETY AND HEALTH...

  8. "Aerobic" Writing: A Writing Practice Model.

    ERIC Educational Resources Information Center

    Crisp, Sally Chandler

    "Aerobic writing" is a writing center strategy designed to keep students in writing "shape." Like aerobic exercise, aerobic writing is sustained for a certain length of time and done on a regular basis at prescribed time intervals. The program requires students to write at least two times a week for approximately an hour each time. Students write,…

  9. Arthritis and Aerobic Exercise: A Review.

    ERIC Educational Resources Information Center

    Ike, Robert W.; And Others

    1989-01-01

    Arthritic patients who regularly do aerobic exercise make significant gains in aerobic and functional status, and in subjective areas like pain tolerance and mood. Still, they are often advised to curtail physical activity. Guidelines are presented for physicians prescribing aerobic exercise. An exercise tolerance test is recommended. (SM)

  10. Ultraviolet vision and foraging in dip and plunge diving birds.

    PubMed

    Håstad, Olle; Ernstdotter, Emma; Odeen, Anders

    2005-09-22

    Many fishes are sensitive to ultraviolet (UV) light and display UV markings during courtship. As UV scatters more than longer wavelengths of light, these signals are only effective at short distances, reducing the risk of detection by swimming predators. Such underwater scattering will be insignificant for dip and plunge diving birds, which prey on fishes just below the water surface. One could therefore expect to find adaptations in the eyes of dip and plunge diving birds that tune colour reception to UV signals. We used a molecular method to survey the colour vision tuning of five families of dip or plunge divers and compared the results with those from sister taxa of other foraging methods. We found evidence of extended UV vision only in gulls (Laridae). Based on available evidence, it is more probable that this trait is associated with their terrestrial foraging habits rather than piscivory. PMID:17148194

  11. James Cameron discusses record dive and science concerns

    NASA Astrophysics Data System (ADS)

    Showstack, Randy; Balcerak, Ernie

    2012-12-01

    James Cameron, the explorer and filmmaker, led a 4 December panel at the AGU Fall Meeting in San Francisco to discuss his daring dive on 26 March to the bottom of the ocean in a one-person vertical "torpedo" submarine, the Deepsea Challenger, and to present some initial science findings from expedition samples and data. The dive touched the bottom of the Challenger Deep, a valley in the floor of the nearly 11-kilometer-deep Mariana Trench in the western Pacific Ocean. The vessel landed close to the same depth and at a location similar to where Don Walsh and Jacques Piccard descended in the Trieste bathyscaphe on 23 January 1960 at a then record-setting depth of 10,911 meters.

  12. Scuba diving: taking the wheelchair out of wheelchair sports.

    PubMed

    Madorsky, J G; Madorsky, A G

    1988-03-01

    In the past, physicians prohibited patients with neuromuscular disease or disability from participating in scuba diving. This report highlights the opportunities that self-contained underwater breathing apparatus (scuba) affords to physically handicapped individuals, to move without assistive devices in a gravity-free environment. The experience of a person with T10 paraplegia is used to illustrate the applicability of a new system of evaluation, training, and certification for scuba diving to patients with a wide variety of disabilities, such as paraplegia, quadriplegia, amputation, cerebral palsy, and poliomyelitis. This review also discusses equipment needs, potential risks, and safety precautions. Physicians are encouraged to support those handicapped individuals who choose to explore the submerged two thirds of our planet for its recreational as well as its potential vocational opportunities. PMID:3348724

  13. Implementation of the submarine diving simulation in a distributed environment

    NASA Astrophysics Data System (ADS)

    Ha, Sol; Cha, Ju-Hwan; Roh, Myung-Il; Lee, Kyu-Yeul

    2012-09-01

    To implement a combined discrete event and discrete time simulation such as submarine diving simulation in a distributed environment, e.g., in the High Level Architecture (HLA)/Run-Time Infrastructure (RTI), a HLA interface, which can easily connect combined models with the HLA/RTI, was developed in this study. To verify the function and performance of the HLA interface, it was applied to the submarine dive scenario in a distributed environment, and the distributed simulation shows the same results as the stand-alone simulation. Finally, by adding a visualization model to the simulation and by editing this model, we can confirm that the HLA interface can provide user-friendly functions such as adding new model and editing a model.

  14. Free-Falling Body Nose Dives in Desert

    NASA Technical Reports Server (NTRS)

    1955-01-01

    This missile-like free-falling body was dropped from an altitude of seven miles. The purpose of this drop was to investigate the efficiency of air inlets of a type suitable for high speed jet aircraft. Its descent rate is checked first by automatic dive brakes (seen partially open) and then by parachute. The body has buried its nose in the California desert. The delicate onboard instruments which recorded performance data were recovered intact.

  15. Parasympathetic preganglionic cardiac motoneurons labeled after voluntary diving.

    PubMed

    Panneton, W Michael; Anch, A Michael; Panneton, Whitney M; Gan, Qi

    2014-01-01

    A dramatic bradycardia is induced by underwater submersion in vertebrates. The location of parasympathetic preganglionic cardiac motor neurons driving this aspect of the diving response was investigated using cFos immunohistochemistry combined with retrograde transport of cholera toxin subunit B (CTB) to double-label neurons. After pericardial injections of CTB, trained rats voluntarily dove underwater, and their heart rates (HR) dropped immediately to 95 ± 2 bpm, an 80% reduction. After immunohistochemical processing, the vast majority of CTB labeled neurons were located in the reticular formation from the rostral cervical spinal cord to the facial motor nucleus, confirming previous studies. Labeled neurons caudal to the rostral ventrolateral medulla were usually spindle-shaped aligned along an oblique line running from the dorsal vagal nucleus to the ventrolateral reticular formation, while those more rostrally were multipolar with extended dendrites. Nine percent of retrogradely-labeled neurons were positive for both cFos and CTB after diving and 74% of these were found rostral to the obex. CTB also was transported transganglionically in primary afferent fibers, resulting in large granular deposits in dorsolateral, ventrolateral, and commissural subnuclei of the nucleus tractus solitarii (NTS) and finer deposits in lamina I and IV-V of the trigeminocervical complex. The overlap of parasympathetic preganglionic cardiac motor neurons activated by diving with those activated by baro- and chemoreceptors in the rostral ventrolateral medulla is discussed. Thus, the profound bradycardia seen with underwater submersion reinforces the notion that the mammalian diving response is the most powerful autonomic reflex known. PMID:24478721

  16. Parasympathetic preganglionic cardiac motoneurons labeled after voluntary diving

    PubMed Central

    Panneton, W. Michael; Anch, A. Michael; Panneton, Whitney M.; Gan, Qi

    2014-01-01

    A dramatic bradycardia is induced by underwater submersion in vertebrates. The location of parasympathetic preganglionic cardiac motor neurons driving this aspect of the diving response was investigated using cFos immunohistochemistry combined with retrograde transport of cholera toxin subunit B (CTB) to double-label neurons. After pericardial injections of CTB, trained rats voluntarily dove underwater, and their heart rates (HR) dropped immediately to 95 ± 2 bpm, an 80% reduction. After immunohistochemical processing, the vast majority of CTB labeled neurons were located in the reticular formation from the rostral cervical spinal cord to the facial motor nucleus, confirming previous studies. Labeled neurons caudal to the rostral ventrolateral medulla were usually spindle-shaped aligned along an oblique line running from the dorsal vagal nucleus to the ventrolateral reticular formation, while those more rostrally were multipolar with extended dendrites. Nine percent of retrogradely-labeled neurons were positive for both cFos and CTB after diving and 74% of these were found rostral to the obex. CTB also was transported transganglionically in primary afferent fibers, resulting in large granular deposits in dorsolateral, ventrolateral, and commissural subnuclei of the nucleus tractus solitarii (NTS) and finer deposits in lamina I and IV-V of the trigeminocervical complex. The overlap of parasympathetic preganglionic cardiac motor neurons activated by diving with those activated by baro- and chemoreceptors in the rostral ventrolateral medulla is discussed. Thus, the profound bradycardia seen with underwater submersion reinforces the notion that the mammalian diving response is the most powerful autonomic reflex known. PMID:24478721

  17. [Diving fitness for scuba divers--what the primary care physician should know].

    PubMed

    Muth, C M; Kemmer, A; Tetzlaff, K

    2005-07-01

    The diving fitness medical examination serves to show and reveal medical conditions that are a contraindication for diving or to evaluate the risk of preexisting conditions. For this reason, it should never have the character of a certification given as a matter of courtesy. Fitness to dive is given if the candidate is healthy and when there are no pathological findings. Even with deviations from the norm, diving is still possible, but with restrictions. Important organ systems for the diving fitness examination are the cardiovascular system, the respiratory organs and the ears. In addition, adequate eyesight is important. The German Society of Diving and Hyperbaric Medicine (GTOUM) has drawn up recommendations on the examination of scuba divers to assist the physician (www.gtuem.org). PMID:16041935

  18. Comparative histology of muscle in free ranging cetaceans: shallow versus deep diving species

    PubMed Central

    Sierra, E.; Fernández, A.; Espinosa de los Monteros, A.; Díaz-Delgado, J.; Bernaldo de Quirós, Y.; García-Álvarez, N.; Arbelo, M.; Herráez, P.

    2015-01-01

    Different marine mammal species exhibit a wide range of diving behaviour based on their breath-hold diving capabilities. They are classically categorized as long duration, deep-diving and short duration, shallow-diving species. These abilities are likely to be related to the muscle characteristics of each species. Despite the increasing number of publications on muscle profile in different cetacean species, very little information is currently available concerning the characteristics of other muscle components in these species. In this study, we examined skeletal muscle fiber type, fiber size (cross sectional area and lesser diameter), intramuscular substrates, and perimysium-related structures, by retrospective study in 146 stranded cetaceans involving 15 different species. Additionally, we investigated diving profile-specific histological features. Our results suggest that deep diving species have higher amount of intramyocyte lipid droplets, and evidence higher percentage of intramuscular adipose tissue, and larger fibre sizes in this group of animals. PMID:26514564

  19. A comparison of auditory brainstem responses across diving bird species

    PubMed Central

    Crowell, Sara E.; Wells-Berlin, Alicia M.; Carr, Catherine E.; Olsen, Glenn H.; Therrien, Ronald E.; Yannuzzi, Sally E.; Ketten, Darlene R.

    2015-01-01

    There is little biological data available for diving birds because many live in hard-to-study, remote habitats. Only one species of diving bird, the black-footed penguin (Spheniscus demersus), has been studied in respect to auditory capabilities (Wever et al. 1969). We therefore measured in-air auditory threshold in ten species of diving birds, using the auditory brainstem response (ABR). The average audiogram obtained for each species followed the U-shape typical of birds and many other animals. All species tested shared a common region of greatest sensitivity, from 1000 to 3000 Hz, although audiograms differed significantly across species. Thresholds of all duck species tested were more similar to each other than to the two non-duck species tested. The red-throated loon (Gavia stellata) and northern gannet (Morus bassanus) exhibited the highest thresholds while the lowest thresholds belonged to the duck species, specifically the lesser scaup (Aythya affinis) and ruddy duck (Oxyura jamaicensis). Vocalization parameters were also measured for each species, and showed that with the exception of the common eider (Somateria mollisima), the peak frequency, i.e. frequency at the greatest intensity, of all species’ vocalizations measured here fell between 1000 and 3000 Hz, matching the bandwidth of the most sensitive hearing range. PMID:26156644

  20. A comparison of auditory brainstem responses across diving bird species.

    PubMed

    Crowell, Sara E; Wells-Berlin, Alicia M; Carr, Catherine E; Olsen, Glenn H; Therrien, Ronald E; Yannuzzi, Sally E; Ketten, Darlene R

    2015-08-01

    There is little biological data available for diving birds because many live in hard-to-study, remote habitats. Only one species of diving bird, the black-footed penguin (Spheniscus demersus), has been studied in respect to auditory capabilities (Wever et al., Proc Natl Acad Sci USA 63:676-680, 1969). We, therefore, measured in-air auditory threshold in ten species of diving birds, using the auditory brainstem response (ABR). The average audiogram obtained for each species followed the U-shape typical of birds and many other animals. All species tested shared a common region of the greatest sensitivity, from 1000 to 3000 Hz, although audiograms differed significantly across species. Thresholds of all duck species tested were more similar to each other than to the two non-duck species tested. The red-throated loon (Gavia stellata) and northern gannet (Morus bassanus) exhibited the highest thresholds while the lowest thresholds belonged to the duck species, specifically the lesser scaup (Aythya affinis) and ruddy duck (Oxyura jamaicensis). Vocalization parameters were also measured for each species, and showed that with the exception of the common eider (Somateria mollisima), the peak frequency, i.e., frequency at the greatest intensity, of all species' vocalizations measured here fell between 1000 and 3000 Hz, matching the bandwidth of the most sensitive hearing range. PMID:26156644

  1. Food habits of diving ducks in the Carolinas

    USGS Publications Warehouse

    Perry, M.C.; Uhler, F.M.

    1982-01-01

    Food habits analyses were conducted on 264 diving ducks (7 species) from North and South Carolina during the 1970'S. The Baltic clam (Macoma balthica) was the predominant food among canvasbacks (Aythya valisineria) from the Pamlico River area, whereas sago pondweed (Potamogeton pectinatus) predominated in birds from impoundments in North and South Carolina. Shoalgrass (Halodule beaudettei) formed 100% of the gullet food and 99% of the gizzard food in redheads (Aythya americana) from Pamlico Sound. Lesser scaup (Aythya affinis) in North Carolina had fed predominantly on mollusks (Mulinia lateralis and Rangia cuneata), whereas widgeon grass (Ruppia maritima) was the predominant food in birds from South Carolina. In North Carolina, ring-necked ducks (Aythya collaris) fed mainly on vegetation, and greater scaup (Aythya marila), bufflehead (Bucephala albeola), and ruddy ducks (Oxyura jamaicensis) fed mainly on Mulinia lateralis. Food habits data from this study when compared with historical food habits of these species indicate that most diving duck species were feeding more on invertebrates and less on submerged aquatic vegetation than in the past. North and South Carolina have a diverse food supply and appear to offer waterfowl adequate wintering habitat based on these food habits studies. Present trends in wintering habitat, however, could adversely affect diving duck populations in the future.

  2. Optimal diving maneuver strategy considering guidance accuracy for hypersonic vehicle

    NASA Astrophysics Data System (ADS)

    Zhu, Jianwen; Liu, Luhua; Tang, Guojian; Bao, Weimin

    2014-11-01

    An optimal maneuver strategy considering terminal guidance accuracy for hypersonic vehicle in dive phase is investigated in this paper. First, it derives the complete three-dimensional nonlinear coupled motion equation without any approximations based on diving relative motion relationship directly, and converts it into linear decoupled state space equation with the same relative degree by feedback linearization. Second, the diving guidance law is designed based on the decoupled equation to meet the terminal impact point and falling angle constraints. In order to further improve the interception capability, it constructs maneuver control model through adding maneuver control item to the guidance law. Then, an integrated performance index consisting of maximum line-of-sight angle rate and minimum energy consumption is designed, and optimal control is employed to obtain optimal maneuver strategy when the encounter time is determined and undetermined, respectively. Furthermore, the performance index and suboptimal strategy are reconstructed to deal with the control capability constraint and the serous influence on terminal guidance accuracy caused by maneuvering flight. Finally, the approach is tested using the Common Aero Vehicle-H model. Simulation results demonstrate that the proposed strategy can achieve high precision guidance and effective maneuver at the same time, and the indices are also optimized.

  3. [Physiopathologic consequences of underwater diving and medical management of divers].

    PubMed

    Méliet, J L

    1996-05-01

    Underwater diving is a very closely medically managed activity. Performing it, the human organism is under the physical laws of pressure and following consequences. The expiratory flows are significatively reduced, enhancing the risk of alveolar hypoventilation at exertion, the central nervous system is the privileged target during inopportune tissue degassing related accidents (leaving 20% of sequellae), barotraumatic injuries threaten middle and inner ear or lung (pulmonary barotrauma is the most severe accident), the toxicity of gas under pressure (i.e. oxygen, nitrogen) exposes to specific risks of loss of consciousness. Lastly, the adaptative mechanisms to immersion can be overflown, leading to pulmonary oedema. Facing these constraints, the practitioner's role begins just before the diver's activity starts by looking for contraindications to diving. It continues during tuition time by teaching him the physiopathology of accidents, their prevention and first cares. Finally, in case of accident, a specialized medical team acts in diagnosis and treatment. From these points of view, diving medicine is a multispecialty medical matter. PMID:8963716

  4. A comparison of auditory brainstem responses across diving bird species

    USGS Publications Warehouse

    Crowell, Sara E.; Berlin, Alicia; Carr, Catherine E; Olsen, Glenn H.; Therrien, Ronald E; Yannuzzi, Sally E; Ketten, Darlene R

    2015-01-01

    There is little biological data available for diving birds because many live in hard-to-study, remote habitats. Only one species of diving bird, the black-footed penguin (Spheniscus demersus), has been studied in respect to auditory capabilities (Wever et al., Proc Natl Acad Sci USA 63:676–680, 1969). We, therefore, measured in-air auditory threshold in ten species of diving birds, using the auditory brainstem response (ABR). The average audiogram obtained for each species followed the U-shape typical of birds and many other animals. All species tested shared a common region of the greatest sensitivity, from 1000 to 3000 Hz, although audiograms differed significantly across species. Thresholds of all duck species tested were more similar to each other than to the two non-duck species tested. The red-throated loon (Gavia stellata) and northern gannet (Morus bassanus) exhibited the highest thresholds while the lowest thresholds belonged to the duck species, specifically the lesser scaup (Aythya affinis) and ruddy duck (Oxyura jamaicensis). Vocalization parameters were also measured for each species, and showed that with the exception of the common eider (Somateria mollisima), the peak frequency, i.e., frequency at the greatest intensity, of all species' vocalizations measured here fell between 1000 and 3000 Hz, matching the bandwidth of the most sensitive hearing range.

  5. Intrapulmonary shunt and SCUBA diving: another risk factor?

    PubMed

    Madden, Dennis; Ljubkovic, Marko; Dujic, Zeljko

    2015-02-01

    Laboratory and field investigations have demonstrated that intrapulmonary arteriovenous anastomoses (IPAVA) may provide an additional means for venous gas emboli (VGE) to cross over to the arterial circulation due to their larger diameter compared to pulmonary microcirculation. Once thought to be the primary cause of decompression sickness (DCS), it has been demonstrated that, even in large quantities, their presence does not always result in injury. Normally, VGE are trapped in the site of gas exchange in the lungs and eliminated via diffusion. When VGE crossover takes place in arterial circulation, they have the potential to cause more harm as they are redistributed to the brain, spinal column, and other sensitive tissues. The patent foramen ovale (PFO) was once thought to be the only risk factor for an increase in arterialization; however, IPAVAs represent another pathway for this crossover to occur. The opening of IPAVAs is associated with exercise and hypoxic gas mixtures, both of which divers may encounter. The goal of this review is to describe how IPAVAs may impact diving physiology, specifically during decompression, and what this means for the individual diver as well as the future of commercial and recreational diving. Future research must continue on the relationship between IPAVAs and the environmental and physiological circumstances that lead to their opening and closing, as well as how they may contribute to diving injuries such as DCS. PMID:25693625

  6. Incremental Knowledge Base Construction Using DeepDive

    PubMed Central

    Shin, Jaeho; Wu, Sen; Wang, Feiran; De Sa, Christopher; Zhang, Ce; Ré, Christopher

    2016-01-01

    Populating a database with unstructured information is a long-standing problem in industry and research that encompasses problems of extraction, cleaning, and integration. Recent names used for this problem include dealing with dark data and knowledge base construction (KBC). In this work, we describe DeepDive, a system that combines database and machine learning ideas to help develop KBC systems, and we present techniques to make the KBC process more efficient. We observe that the KBC process is iterative, and we develop techniques to incrementally produce inference results for KBC systems. We propose two methods for incremental inference, based respectively on sampling and variational techniques. We also study the tradeoff space of these methods and develop a simple rule-based optimizer. DeepDive includes all of these contributions, and we evaluate Deep-Dive on five KBC systems, showing that it can speed up KBC inference tasks by up to two orders of magnitude with negligible impact on quality. PMID:27144081

  7. Evolutionary Genetics of Hypoxia Tolerance in Cetaceans during Diving.

    PubMed

    Tian, Ran; Wang, Zhengfei; Niu, Xu; Zhou, Kaiya; Xu, Shixia; Yang, Guang

    2016-03-01

    Hypoxia was a major challenge faced by cetaceans during the course of secondary aquatic adaptation. Although physiological traits of hypoxia tolerance in cetaceans have been well characterized, the underlying molecular mechanisms remain unknown. We investigated the sequences of 17 hypoxia-tolerance-related genes in representative cetaceans to provide a comprehensive insight into the genetic basis of hypoxia tolerance in these animals. Genes involved in carrying and transporting oxygen in the blood and muscle (hemoglobin-α and β, myoglobin), and genes involved in the regulation of vasoconstriction (endothelin-1, -2, and -3; endothelin receptor type A and B; adrenergic receptor α-1D; and arginine vasopressin) appear to have undergone adaptive evolution, evidence for positive selection on their particular sites, and radical physiochemical property changes of selected condons. Interestingly, "long-diving" cetaceans had relatively higher ω (dN/dS) values than "short-diving" cetaceans for the hemoglobin β gene, indicating divergent selective pressure presented in cetacean lineages with different diving abilities. Additionally, parallel positive selection or amino acid changes (ADRA1D: P50A, A53G,AVPR1B: I/V270T) among animals exposed to different hypoxia habitats reflect functional convergence or similar genetic mechanisms of hypoxia tolerance. In summary, positive selection, divergent selective pressures, and parallel evolution at the molecular level provided some new insights into the genetic adaptation of hypoxia tolerance. PMID:26912402

  8. High-affinity hemoglobin and blood oxygen saturation in diving emperor penguins.

    PubMed

    Meir, Jessica U; Ponganis, Paul J

    2009-10-01

    The emperor penguin (Aptenodytes forsteri) thrives in the Antarctic underwater environment, diving to depths greater than 500 m and for durations longer than 23 min. To examine mechanisms underlying the exceptional diving ability of this species and further describe blood oxygen (O2) transport and depletion while diving, we characterized the O2-hemoglobin (Hb) dissociation curve of the emperor penguin in whole blood. This allowed us to (1) investigate the biochemical adaptation of Hb in this species, and (2) address blood O2 depletion during diving, by applying the dissociation curve to previously collected partial pressure of O2 (PO2) profiles to estimate in vivo Hb saturation (SO2) changes during dives. This investigation revealed enhanced Hb-O2 affinity (P50=28 mmHg, pH 7.5) in the emperor penguin, similar to high-altitude birds and other penguin species. This allows for increased O2 at low blood PO2 levels during diving and more complete depletion of the respiratory O2 store. SO2 profiles during diving demonstrated that arterial SO2 levels are maintained near 100% throughout much of the dive, not decreasing significantly until the final ascent phase. End-of-dive venous SO2 values were widely distributed and optimization of the venous blood O2 store resulted from arterialization and near complete depletion of venous blood O2 during longer dives. The estimated contribution of the blood O2 store to diving metabolic rate was low and highly variable. This pattern is due, in part, to the influx of O2 from the lungs into the blood during diving, and variable rates of tissue O2 uptake. PMID:19801437

  9. Converting chemical energy into electricity through a functionally cooperating device with diving-surfacing cycles.

    PubMed

    Song, Mengmeng; Cheng, Mengjiao; Ju, Guannan; Zhang, Yajun; Shi, Feng

    2014-11-01

    A smart device that can dive or surface in aqueous medium has been developed by combining a pH-responsive surface with acid-responsive magnesium. The diving-surfacing cycles can be used to convert chemical energy into electricity. During the diving-surfacing motion, the smart device cuts magnetic flux lines and produces a current, demonstrating that motional energy can be realized by consuming chemical energy of magnesium, thus producing electricity. PMID:25146589

  10. Surface pauses in relation to dive duration in imperial cormorants; how much time for a breather?

    PubMed

    Wilson, Rory P; Quintana, Flavio

    2004-05-01

    Air-breathing animals diving to forage can optimize time underwater by diving with just enough oxygen for the projected performance underwater. By so doing they surface with minimal body oxygen levels, which leads to maximal rates of oxygen uptake. We examined whether imperial cormorants Phalacrocorax atriceps adhere to this by examining dive:pause ratios in birds diving for extended, continuous periods to constant depths, assuming that the oxygen used underwater was exactly replenished by the periods at the surface. Examination of the cumulative time spent in surface pauses relative to the cumulative time spent in diving showed that surface pauses increase according to a power curve function of time spent in the dive or water depth. In a simplistic model we considered the rate at which birds expended energy underwater to be constant and that the rate of oxygen replenishment during the surface pause was directly proportional to the oxygen deficit. We then worked out values for the rate constant for the surface pause before using this constant to examine bird body oxygen levels immediately pre- and post dive. The model predicted that imperial cormorants do not submerge with just enough oxygen to cover their projected dive performance but rather dive with substantial reserves, although these reserves decrease with increasing dive depth/duration. We speculate that these oxygen reserves may be used to enhance bird survival when rare events, such as the appearance of predators or discovery of large prey requiring extended handling time, occur. The form of the oxygen saturation curve over time at the surface means that the time costs for maintaining constant oxygen reserves become particularly onerous for long, deep dives, so the observed decrease in reserves with increasing dive duration is expected in animals benefiting by optimizing for time. PMID:15107434

  11. Lesson of the month 1: A review of a diving emergency.

    PubMed

    Ashken, Lucy; Ross-Parker, Andrew; Shalaby, Tamer

    2015-02-01

    Physicians should consider barotrauma and decompression illness (DCI) in any patient presenting after a recent scuba dive, even apparently shallow dives. If and when DCI is suspected, clinicians should act without delay to transfer the patient to a recompression facility, even if diagnostic certainty has not been attained. We present a case of hyperbaric injury in an asthmatic woman who had an atypical presentation in view of the depth of dive. PMID:25650213

  12. Deep Dive Topic: Approach to ignition

    SciTech Connect

    Hurricane, O. A.; Kline, J. L.; Meezan, N.; Mackinnon, A.

    2015-07-14

    The current high-foot and related implosions have adequate CR and implosion velocity to ignite, but require improved finesse particularly in, but not limited to, implosion symmetry. This is being pursued. The challenge of controlling drive symmetry is also motivating lower convergence ratio designs. These require higher velocity implosions and are also being pursued.

  13. Decompression syndrome and the evolution of deep diving physiology in the Cetacea

    NASA Astrophysics Data System (ADS)

    Beatty, Brian Lee; Rothschild, Bruce M.

    2008-09-01

    Whales repetitively dive deep to feed and should be susceptible to decompression syndrome, though they are not known to suffer the associated pathologies. Avascular osteonecrosis has been recognized as an indicator of diving habits of extinct marine amniotes. Vertebrae of 331 individual modern and 996 fossil whales were subjected to macroscopic and radiographic examination. Avascular osteonecrosis was found in the Oligocene basal odontocetes (Xenorophoidea) and in geologically younger mysticetes, such as Aglaocetus [a sister taxon to Balaenopteridae + (Balaenidae + Eschrichtiidae) clade]. These are considered as early “experiments” in repetitive deep diving, indicating that they independently converged on their similar specialized diving physiologies.

  14. [A CASE OF NATTOU (FERMENTED-SOYBEAN)-INDUCED LATE-ONSET ANAPHYLAXIS FOLLOWING SCUBA DIVING].

    PubMed

    Nagakura, Toshikazu; Tanaka, Katsuichirou; Horikawa, Satoshi

    2015-06-01

    We here report a 34-years old male who had nattou-(fermented-soybean) induced late-onset anaphylaxis following SCUBA diving to about 20 m in the ocean off a small remote Japanese island (Kuroshima, Okinawa). He had eaten nattou for breakfast at 7:30 am. He traveled by boat to the dive site, dove twice and then ate lunch at 12:30 on the diving boat (no nattou at lunch). After lunch at 14:30 he dove again (third dive of the day) during which time itchiness started. Back on the diving boat, urticarial was noticed. At 15:30, while washing his diving gear at the diving shop near the harbor, he fainted. A physician arrived on the scene at 15:45. Chest sound was clear and SpO2 was 98%, and blood pressure was 60/- mmHg. Intra-venous hydrocortisone was given, however, his recovery was not satisfactory. Then he was transferred to the Yaeyama Hospital by helicopter at 17:45. The examination of diving computer analysis reveals no sign of increased residual nitrogen, denying the possibility of decompression syndrome. Prick to prick test shows a strongly positive response to nattou. Nattou-induced late-onset anaphylaxis following SCUBA diving was suspected. PMID:26380912

  15. Time Variation of the Distance Separating Bomb and Dive Bomber Subsequent to Bomb Release

    NASA Technical Reports Server (NTRS)

    Mathews, Charles W.

    1952-01-01

    A study has been made of the variation of the distance separating bomb and aircraft with time after release as applied to dive-bombing operations, Separation distances determined from this study are presented in terms of two variables only, dive angle and maximum airplane accelerometer reading; the values of separation distance include the effects of delay in initiation of the pull-out and lag in attainment of the maximum normal acceleration.Contains analysis and calculations of the separation distances between bomb and dive bomber following bomb release, Separation distances as determined by the dive angle and the maximum airplane accelerometer reading are presented in a single chart.

  16. Respiratory effects of a single dive to 50 meters in sport divers with asymptomatic respiratory atopy.

    PubMed

    Tetzlaff, K; Staschen, C M; Struck, N; Mutzbauer, T S

    2001-02-01

    Increasing popularity of sports diving makes it likely that subjects with allergic respiratory diseases will be involved in diving with self contained underwater breathing apparatus (scuba). The present study evaluated the effects of a single scuba-dive on pulmonary function in subjects with respiratory atopy. Specific airways conductance (sGaw), residual volume (RV), forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV1), mid expiratory flow at 50% of FVC (MEF50), and transfer factor for carbon monoxide (TLCO) were measured in 9 sport divers with a history of hay fever and 9 matched healthy sport divers (control) before, 3 hours and 24 hours after a wet hyperbaric chamber dive to a depth of 50 m. Airway hyperresponsiveness (AHR) was assessed by methacholine challenge 4 weeks after the dive. Atopic subjects and controls did not differ with respect to anthropometric data, diving experience, and predive lung function. A 3% reduction in FVC was found 24h after the dive (p < 0.05) in both groups, whereas sGaw decreased by 15% 24 h after the dive (p < 0.05) in the subjects with respiratory atopy only. Postdive changes in RV, FEV1, MEF50, and TLCO did not reach level of statistical significance. AHR was obtained in 8/9 subjects with respiratory atopy. We conclude that subjects with atopic sensitization and asymptomatic AHR may be more susceptible to effects of diving on pulmonary function. PMID:11281622

  17. Electrocardiographic aspects of deep dives in elite breath-hold divers.

    PubMed

    Lemaître, F; Lafay, V; Taylor, M; Costalat, G; Gardette, B

    2013-01-01

    The cardiac diving response, 12-lead electrocardiogram (ECG) and the prevalence, time of onset, and possible associations of cardiac arrhythmias were examined during deep breath-hold (BH) dives. Nine elite BH divers (33.2 +/- 3.6 years; mean +/- SD) performed one constant-weight dive of at least 75% of their best personal performance (70 +/- 7 meters for 141 +/- 22 seconds) wearing a 12-lead ECG Holter monitor. Diving parameters (depth and time), oxygen saturation (SaO2), blood lactate concentration and ventilatory parameters were also recorded. Bradycardia during these dives was pronounced (52.2 +/- 12.2%), with heart rates dropping to 46 +/- 10 beats/minute. The diving reflex was strong, overriding the stimulus of muscular exercise during the ascent phase of the dive for all divers. Classical arrhythmias occurred, mainly after surfacing, and some conduction alterations were detected at the bottom of the dives. The BH divers did not show any right shift of the QRS electrical axis during their dives. PMID:23682546

  18. Risk of decompression sickness in extreme human breath-hold diving.

    PubMed

    Fitz-Clarke, J R

    2009-01-01

    The risk of decompression sickness (DCS) in human breath-hold diving is expected to increase as dives progress deeper until a depth is reached where total lung collapse stops additional nitrogen gas uptake. We assembled a database of all documented human breath-hold dives to 100 metres or greater, including both practice and record dives. Between 1976 and 2006 there were 192 such dives confirmed by 24 divers (18 male, 6 female). The deepest dive was to 209 metres. There were two drowning fatalities, and two cases ofDCS. Depth-time risk estimates for DCS were derived for single breath-hold dives by modifying probabilistic decompression models calibrated with data from short deep no-stop air dives and submarine escape trials using maximum-likelihood estimation. Arterial nitrogen levels during apnea were adjusted for lung compression and decreased cardiac output. Predicted DCS risk is negligible up to about 100 metres, beyond which risk increases nonlinearly and reaches a plateau around 5 to 7 percent when total lung collapse occurs beyond 230 metres. Results are consistent with data available from deep breath-hold dives. PMID:19462748

  19. Aerobic microbial enhanced oil recovery

    SciTech Connect

    Torsvik, T.; Gilje, E.; Sunde, E.

    1995-12-31

    In aerobic MEOR, the ability of oil-degrading bacteria to mobilize oil is used to increase oil recovery. In this process, oxygen and mineral nutrients are injected into the oil reservoir in order to stimulate growth of aerobic oil-degrading bacteria in the reservoir. Experiments carried out in a model sandstone with stock tank oil and bacteria isolated from offshore wells showed that residual oil saturation was lowered from 27% to 3%. The process was time dependent, not pore volume dependent. During MEOR flooding, the relative permeability of water was lowered. Oxygen and active bacteria were needed for the process to take place. Maximum efficiency was reached at low oxygen concentrations, approximately 1 mg O{sub 2}/liter.

  20. Development of aerobic and anaerobic metabolism in cardiac and skeletal muscles from harp and hooded seals.

    PubMed

    Burns, J M; Skomp, N; Bishop, N; Lestyk, K; Hammill, M

    2010-03-01

    In diving animals, skeletal muscle adaptations to extend underwater time despite selective vasoconstriction include elevated myoglobin (Mb) concentrations, high acid buffering ability (beta) and high aerobic and anaerobic enzyme activities. However, because cardiac muscle is perfused during dives, it may rely less heavily on Mb, beta and anaerobic pathways to support contractile activity. In addition, because cardiac tissue must sustain contractile activity even before birth, it may be more physiologically mature at birth and/or develop faster than skeletal muscles. To test these hypotheses, we measured Mb levels, beta and the activities of citrate synthase (CS), beta-hydroxyacyl-CoA dehydrogenase (HOAD) and lactate dehydrogenase (LDH) in cardiac and skeletal muscle samples from 72 harp and hooded seals, ranging in age from fetuses to adults. Results indicate that in adults cardiac muscle had lower Mb levels (14.7%), beta (55.5%) and LDH activity (36.2%) but higher CS (459.6%) and HOAD (371.3%) activities (all P<0.05) than skeletal muscle. In addition, while the cardiac muscle of young seals had significantly lower [Mb] (44.7%) beta (80.7%) and LDH activity (89.5%) than adults (all P<0.05), it was relatively more mature at birth and weaning than skeletal muscle. These patterns are similar to those in terrestrial species, suggesting that seal hearts do not exhibit unique adaptations to the challenges of an aquatic existence. PMID:20154189