Duration Of Swimming Research Articles

Gender-Related Characteristics of Responding to Prolonged Psychoemotional Stress in Mice

The behavior of male and female C57BL/6J mice was studied after prolonged psychoemotional stress imposed by enforced cohabitation with an aggressive male on the other side of a partition in the cage and daily witnessing of 10-minute confrontations between the aggressor and another male placed with it. The elevated plus maze test demonstrated marked anxiety in mice of both genders after one month of psychoemotional stress. However, only females, but not males, showed an increase in the duration of passive swimming in the Porsolt test, along with some reduction in communicativeness in the partition test. Thus, these studies showed a more marked reaction to prolonged pscyhoemotional stress in females than in males.

Thiamine tetrahydrofurfuryl disulfide improves energy metabolism and physical performance during physical-fatigue loading in rats

Impaired energy metabolism is considered a possible cause of fatigue. The thiamine derivative, thiamine tetrahydrofurfuryl disulfide (TTFD), is prescribed and is also an over-the-counter drug for the attenuation of fatigue. It is readily absorbed from the intestinal tract and converted into thiamine pyrophosphate (TPP), which plays an important role as a cofactor for enzymes of metabolic pathways involved in the production of adenosine triphosphate (ATP). We postulated that TTFD has an anti-fatigue effect by improving energy metabolism during physical-fatigue loading. Here, we initially used the forced swimming test to determine whether daily TTFD or thiamine for 5 days has anti-fatigue effects on weight-loaded rats. The swimming duration of TTFD-, but not of thiamine-treated rats, was significantly longer than that of control rats (P < .05). Based on these findings, we examined changes in the levels of thiamine and its phosphate esters in various organs and the effect of TTFD on ATP levels in skeletal muscle after forced swimming, to determine the cellular mechanisms of the anti-fatigue effect of TTFD. Daily TTFD resulted in a characteristic distribution of thiamine and its phosphate esters in rat skeletal muscle, liver, kidney, heart, brain, and plasma. Furthermore, daily TTFD attenuated the decrease in ATP content in the skeletal muscle caused by forced swimming with a weight load for a defined period (150 s). These results indicate that TTFD exerts anti-fatigue effects by improving energy metabolism during physical fatigue.

Large-scale variation in seasonal swimming patterns of plaice in the North Sea

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 392:167-178 (2009) - DOI: https://doi.org/10.3354/meps08213 Large-scale variation in seasonal swimming patterns of plaice in the North Sea E. Hunter1,*, R. J. Cotton2, J. D. Metcalfe1, J. D. Reynolds3 1Centre for Environment, Fisheries and Aquaculture Science, Lowestoft Laboratory, Pakefield Road, Lowestoft, Suffolk NR33 0HT, UK 2Mathematical Sciences Unit, Health & Safety Laboratory, Harpur Hill, Buxton, Derbyshire SK17 9JN, UK 3Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada *Email: ewan.hunter@cefas.co.uk ABSTRACT: We examined the mid-water swimming activity of 139 mature female plaice Pleuronectes platessa L. These were tagged with electronic data storage tags (DST1s and DST3s) to test whether swimming at different times of the year differed among areas of the North Sea with average tidal current velocities ranging from fast (West), to intermediate (East), to slow (North). Longer swimming duration and more tidal activity were predicted for the western group, where fast-flowing tidal currents allow efficient selective tidal stream transport. Individual depth data were converted into binary records representing either swimming or resting; repeated patterns of swimming were analysed according to cycle-length frequencies. Most swimming occurred during expected times of migration and spawning (October to March). Plaice infrequently spent >5 h in mid-water, and rarely left the sea-bed during summer. DST1 tagged plaice (West only) spent the longest times swimming (p > 0.001), but there was no significant effect of Area for DST3s (all areas), suggesting that swimming plays an important behavioural role in migration in addition to transport between feeding and spawning areas. Tidal patterns of activity occurred in all 3 sub-stocks, predominantly during the migratory period (albeit at a significantly lower frequency in the North). These data provide one of few examples where the annual behaviour patterns of a fish stock have been recorded across a large part of its geographical range. The results have important implications for understanding the energetics of fish migration and the availability of demersal stocks to capture by commercial and survey vessels. KEY WORDS: Plaice · Migration · Data storage tags · Swimming · Behaviour · Fisheries Full text in pdf format PreviousNextCite this article as: Hunter E, Cotton RJ, Metcalfe JD, Reynolds JD (2009) Large-scale variation in seasonal swimming patterns of plaice in the North Sea. Mar Ecol Prog Ser 392:167-178. https://doi.org/10.3354/meps08213 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 392. Online publication date: October 19, 2009 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2009 Inter-Research.

High-frequency depth recording reveals the vertical movement of flounder in the Tsugaru Strait of northern Japan

Analysis of high-frequency depth-recording data of adult Japanese flounder Paralichthys olivaceus (Temminck & Schlegel) with depth/temperature logging tags, released in the Tsugaru Strait of northern Japan, has yielded new insights into behavioural differences on vertical movement. Here, we document diel differences in fine-temporal-scale swimming behaviour observed from six flounder released during the no-spawning season. While the flounder remained on the seabed for the majority of the recording period, fish occasionally left the seabed, swam into the water column and then swam back to the seabed. The mean swimming duration per tagged fish ranged from 44 ± 49 to 94 ± 164 s, with a maximum observed swimming duration of 44.5 min. Vertical movements included one or more clear ascent and descent phases highlighted by a distinct peak. Our results reveal that in the no-spawning season nocturnal swimming is more active and frequent than during the day. Our results provide important information about diel differences in swimming behaviour with respect to vertical movement and also show the vulnerability of Japanese flounder to capture by bottom-fishing gear (e.g. trawling) during the day.

Stimulatory Effects of Ferulic Acid on Endurance Exercise Capacity in Mice

Ferulic acid was orally administered to mice in order to investigate its effects on exercise endurance capacity. When a single administration of ferulic acid was given to the mice in an adjustable-current water pool, the duration of exhaustive swimming was longer than that exhibited by the mice in the control group. Also, when the mice were exhaustively exercised for 3 consecutive days, no change in swimming time was found in the ferulic acid-administered group on the final day, and a large decrease in the untreated mice. Administration of ferulic acid efficiently activated the hepatic antioxidative defense system during exercise. The mice that received ferulic acid showed significant increases in the activity of hepatic antioxidant enzymes such as superoxide dismutase, catalase, and glutathione-S-transferase. Furthermore, an increased glutathione level was observed, while the malondialdehyde content was reduced. These results suggest that ferulic acid possesses stimulatory effects that can enhance exercise endurance capacity and reduce fatigue by elevating antioxidative potentials.

Widening the Pool of Factors: Studies Needed to Assess Asthma–Swimming Link

Vol. 117, No. 4 EnvironewsOpen AccessWidening the Pool of Factors: Studies Needed to Assess Asthma–Swimming Link Angela Spivey Angela Spivey Search for more papers by this author Published:1 April 2009https://doi.org/10.1289/ehp.117-a162aAboutSectionsPDF ToolsDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InReddit Several epidemiologic studies have suggested an association between childhood asthma and exposure to disinfection by-products (DBPs) in the swimming pool environment. In August 2007 a group of clinicians, epidemiologists, exposure scientists, pool operations experts, and analytical chemists met to discuss the literature on childhood asthma and swimming pools, and to develop recommendations for future research. In a review based on the results of that workshop, the authors state that current evidence, while suggestive, is inconclusive for an association with childhood asthma, and they point to several substantial data gaps that must be filled [EHP117:500–507; Weisel et al.].The authors articulate several variables that must be measured in more detail to properly characterize inhalation exposure to chemicals around pools. The review calls for a comprehensive assessment of a substantially larger number of chemicals in the pool area than the limited number of DBPs studied to date. Earlier epidemiologic studies suggested trichloramine as a DBP of interest, but one 2007 study revealed previously unknown volatile DBPs in the air surrounding swimming pools.The frequency and extent of exposure to chemicals around pools also must be studied. In research to date, only simple exposure indices have been used, including whether the pool was indoors or outdoors, specific disinfection treatment, whether the child swam in or was simply present at an indoor pool, and cumulative duration of swimming. But to evaluate the breathing rate and DBP dose delivered to the lungs, more detailed, validated assessments of activity levels are needed. To obtain these data, the authors recommend that future studies use prospective questionnaires in which participants report their pool use and activity levels over time as they occur.The authors also point to the need for studies that define asthma cases in a rigorous, reproducible way, utilizing the International Study of Asthma and Allergy in Children questionnaire. Previous studies have often used clinical diagnoses, but this may be insufficient for epidemiologic studies because asthma is a heterogeneous disease with no single reliable diagnostic test. Additional needs include development and validation of new biomarkers for asthmatic reactivity and studies designed to refine guidelines for proper pool maintenance and disinfection to reduce levels of DBPs.The authors conclude this research area requires studies across multiple disciplines. Once chemicals of interest are identified, studies of the mechanisms behind the possible association—such as oxidative stress, inflammation, and changes in lung permeability—may be useful. But long-range prospective studies starting in early childhood will be needed to better gauge the relationship between swimming pools and childhood asthma.Absent conclusive studies, the authors say children’s exposures should be minimized. Pool managers must be well educated about pool chemistry so they can understand the potential dangers of disinfectants and DBPs. Swimmers, too, must be educated about the need for proper pool hygiene (for example, showering before swimming and not urinating in the pool), as swimmer hygiene can affect the formation of DBPs and the amount of disinfectant used.A number of variables still must be studied in greater detail to better characterize exposure to pool-related chemicals.FiguresReferencesRelatedDetails Vol. 117, No. 4 April 2009Metrics About Article Metrics Publication History Originally published1 April 2009Published in print1 April 2009 Financial disclosuresPDF download License information EHP is an open-access journal published with support from the National Institute of Environmental Health Sciences, National Institutes of Health. All content is public domain unless otherwise noted. Note to readers with disabilities EHP strives to ensure that all journal content is accessible to all readers. However, some figures and Supplemental Material published in EHP articles may not conform to 508 standards due to the complexity of the information being presented. If you need assistance accessing journal content, please contact [email protected]. Our staff will work with you to assess and meet your accessibility needs within 3 working days.

상대적 수영운동 강도가 흰쥐 갈색지방조직의 UCP-1과 UCP-3 mRNA 발현, 혈중 인슐린 및 혈당에 미치는 효과

본 연구에서는 F344계 흰쥐를 대상으로 8주간 저강도 운동군과 고강도 운동군으로 나누어 수영운동을 실시하여, 갈색지방조직 내 UCP-1과 UCP-3mRNA 발현을 관찰하고 혈당 및 인슐린 수준이 어떠한 변화를 나타내는지 알아보았다. 그 결과 저강도 수영을 실시한 그룹이 대조군과 고강도 운동그룹보다 갈색지방조직 내 UCP-1과 UCP-3 mRNA 발현이 증가되는 것을 관찰하였으며, 고강도 수영군에서 대조군 보다 인슐린 수준이 낮게 나타났으나 혈당에서는 유의한차가 나타나지 않았다. 하지만 저강도 수영군에서 대조군보다 혈당 및 인슐린 수준이 유의하게 감소하는 것을 관찰하였다. 이러한 결과는 저강도 수영운동이 갈색지방조직 내 UCP-1과 UCP-3mRNA 발현을 증가시키고, 당대사를 활성화하여 인슐린민감도를 개선시킬 수 있음을 보여주는 결과이다. The purpose of this study was to investigate the UCP-1, UCP-3 mRNA expression in brown adipose tissue with glycometabolism according to intensity and duration of swimming in rat. F344 rat were randomly divided into three groups (n=10 in each group): control (CON), low-intensity swimming (LIS) groups, and high-intensity swimming (HIS) groups. Animals in the LIS group were forced to swim in swimming pool for 30min once a day for 8 consecutive weeks with a light intensity. In the HIS group, the rats repeated fifteen 20-s swimming bouts with a weight equivalent to 10% of body weight for 8weeks, respectively. The present result demonstrated that in LIS group, serum insulin and glucose levels significantly decreased in LIS group compared to CON. Brown adipose tissue UCP-1 and UCP-3mRNA expression was significantly increase in LIS group compared to CON and HIS groups. From those results, it can be suggested that low-intensity swimming may improve glycometablism control by up-regulating UCP-1 and UCP-3mRNA expression.

Biological Monitoring for Detection of Toxic Chemicals in Water by the Swimming Behavior of Small Freshwater Fish

We conducted exposure tests using three small fish species, medaka (Oryzias latipes), guppy (Poecilia reticulata), and white cloud mountain minnow (Tanichthys albonubes). The fish were exposed to nominal concentrations of test chemicals (potassium cyanide [KCN; 1 and 5 mg/L], sodium cyanide [NaCN; 1 and 5 mg/L], and aldicarb [5 mg/L]) for one hour. We used two cameras for tracking the fish behavior in three dimensional (3D) data. Then the 3D data were analyzed for fish behavior such as, swimming speed and surfacing behavior. Swimming speed and position of the three fish species were affected by KCN, NaCN, and aldicarb exposure test. Three fish species showed the different behavioral patterns after the exposure of test chemicals. Although the patterns of effect on behavioral parameters differed among the test species and toxic chemicals, we could find the significant effects on both the frequency of high swimming speed and duration time of surfacing behavior in test fish. We concluded that three fish species are useful species for monitoring the water quality by their behavioral changes.

Neurochemical and behavioral alterations in an inflammatory model of depression: Sex differences exposed

It is firmly established that women experience major depression (MD) at roughly twice the rate of men and that dysregulation of the immune system is associated with the appearance and course of this condition. In the present study, we sought to identify whether “sickness behavior”, an inflammatory model of MD, is characterized by sexual dimorphism by focusing on both neurochemical and behavioral responses. Therefore, we investigated the serotonergic and dopaminergic activity of various brain regions implicated in the pathophysiology of affective disorders (hypothalamus, hippocampus, prefrontal cortex, amygdala and striatum) in response to a mild lipopolysaccharide (LPS) challenge, in rats of both sexes. According to our results, at 2 h post-LPS administration (100 μg/kg i.p.), the neurochemical substrate was primarily altered in female rats with the serotonergic function being markedly enhanced in all brain regions examined. Dopaminergic activation following immune system sensitization with LPS was not apparent in male rats and only modest in female rats with the exception of striatum. LPS administration also affected sickness-associated behaviors to a different extent in male and female rats, as assessed in the forced swim test (FST), the hot plate test (HPT) and the open-field arena. LPS-treated female rats coped better with the stressful FST procedure, as evidenced by an increase in swimming duration. The effects of LPS treatment appeared to be more robust in male rats, as far as suppression of locomotor activity is concerned, while the antinociceptive properties of LPS were evident in both sexes though showing sex-dependent kinetics. Moreover, when traditional measures of sickness (i.e. sucrose consumption, social exploration, food intake) were assessed, males and females appeared to be similarly affected, except for food intake. These data are the first to demonstrate that the serotonergic system is affected to a greater extent in female rats at 2 h post-LPS administration and further contribute to our understanding regarding sexual dimorphism upon sickness establishment.

Antistress, adoptogenic activity ofSida cordifoliaroots in mice

Ethanol extract of roots of Sida cordifolia was evaluated for antistress, adaptogenic activity using cold restraint stress and swim endurance in mice. Mice pretreated with extract of Sida cordifolia showed significant improvement in the swim duration and reduced the elevated WBC, blood glucose and plasma cortisone.

Effects of 12 Weeks of Exercise on Hepatic TNF-α and PPARα in an Animal Model of High-Fat Diet-Induced Nonalcoholic Steatohepatitis

Nonalcoholic steatohepatitis (NASH) is hepatic inflammation caused by a buildup of fat in the liver. This study was designed to examine whether the NASH-associated increase in hepatic TNF-α mRNA expression and serum TNF-α, and decrease in hepatic PPARα mRNA expression in rats secondary to 12-week consumption of a high-fat diet would be attenuated with concurrent exercise. A total of 28 male Sprague-Dawley strain rats were randomly assigned into four groups: standard diet without (C, n = 6) and with (E, n = 7) concurrent exercise; and high-fat diet without (H, n = 8) and with (HE, n = 7) concurrent exercise. The mean daily energy intake during the intervention period resulting from the standard and high-fat diets was approximately 82 kcal and 95 kcal, respectively. Swimming exercise was carried out in the E and HE groups for 12 weeks. The initial swimming duration of 30 minutes was progressively increased by 10 min·d −1 to 90 minutes by the end of the fourth week, which then remained unchanged. NASH revealed by histological activity index, which occurred in the H but not the C group, was alleviated in the HE group. Moreover, the upregulation of hepatic TNF-α mRNA expression and serum TNF-α, and downregulation of hepatic PPARα mRNA expression, which were shown in the H group, were attenuated in the HE group. Such findings suggest that long-term exercise carried out concurrently with consumption of a high-fat diet could alleviate high-fat diet-induced NASH. These may be partly attributable to the attenuation of hepatic TNF-α overexpression and the upregulation of hepatic PPARα mRNA expression.

Frequency of climbing behavior as a predictor of altered motor activity in rat forced swimming test

Previous work has shown that the frequency of climbing behavior in rats submitted to the forced swimming test (FST) correlated to the section's crosses in the open field test, which suggest it might be taken as a predictor of motor activity in rat FST. To investigate this proposal, the frequency, duration, as well as the ratio duration/frequency for each behavior expressed in the FST (immobility, swimming and climbing) were compared in animals treated with a motor stimulant, caffeine (CAF), and the antidepressant, clomipramine (CLM). Male Wistar rats were submitted to 15 min of forced swimming (pre-test) and 24 h later received saline (SAL, 1 ml/kg, i.p.) or CAF (6.5 mg/kg, i.p.) 30 min prior a 5-min session (test) of FST. To validate experimental procedures, an additional group of rats received three injections of SAL (1 ml/kg, i.p.) or clomipramine (CLM, 10 mg/kg, i.p.) between the pre-test and test sessions. The results of the present study showed that both drugs, CLM and CAF, significantly reduced the duration of immobility and significantly increased the duration of swimming. In addition, CAF significantly decreased the ratio of immobility, and CLM significantly increased the ratio of swimming and climbing. Moreover, CLM significantly increased the duration of climbing but only CAF increased the frequency of climbing. Thus, it seems that the frequency of climbing could be a predictor of altered motor activity scored directly in the FST. Further, we believe that this parameter could be useful for fast and reliable discrimination between antidepressant drugs and stimulants of motor activity.

P.3.b.002 Isolation rearing-induced cognitive deficits involves opposing NMDA/D1 receptor changes in rat frontal cortex

Post-weaning rats were housed alone or in groups for a period of 4 or 8 weeks. A portion of the animals received tricyclic antidepressant treatment, desipramine 20 mg/kg/day, during this period. Animals were then tested behaviorally by forced swimming. Isolation was associated with significantly longer durations of immobility during forced swimming. This was blocked by desipramine treatment. Desipramine treatment did not have a significant effect on the swimming durations of group-housed rats. Hindbrain and midbrain levels of catecholamines were subsequently measured and turnover rates estimated by administration of α-methyl-p-tyrosine or saline. Isolated rats had increased levels and decreased turnover of catecholamines. The increase in norepinephrine but not dopamine levels was blocked by desipramine, while antidepressant effects on turnover could not be tested with this method. Reduced social stimulation thus appears to be associated with reduced catecholamine release which may result in the accumulation of these transmitters in the central nervous system. Treatment with desipramine appeared essentially to compensate for reduced social stimulation, blocking isolation-induced noradrenergic neurochemical changes, while having few significant effects on control animals. This study may be helpful in furthering our understanding of how the interaction of organisms with their environment influence catecholamine systems and how antidepressants may act to restore function.

Foraging behavior of bay anchovy larvae, Anchoa mitchilli

Foraging behavior of the bay anchovy larvae, Anchoa mitchilli was characterized by silhouette video photography. Swimming speed, pause frequency and duration, burst duration, reactive distance (RD), horizontal and vertical reaction angle (HRA, VRA), and length of the predation cycle were estimated over a range of sizes and stages of development. First feeding larvae displayed a distinct pause-travel search behavior that included horizontal rotation of their body to the right or left to scan a new volume of water. Pause duration was affected by light intensity in small larvae and significantly decreased in length of time as larvae grew (ANOVA, p < 0.01). Duration of swimming bursts between pauses was short (mean = 0.13 ± 0.03 s). Average swimming speeds increased with size from a mean of 0.50 ± 0.39 BL · s - 1 (body lengths) at first feeding to 2.25 ± 1.27 BL · s - 1 at 12 mm SL. Mean RD of bay anchovy larvae at 10 lux and corrected for vertical angle was 0.65 BL and increased to 0.92 and 1.00 BL at 100 and 250 lux, respectively. The average RD increased in the presence of turbidity from 0.65 to 0.83 BL at 10 lux. Reducing light (250, 100, 10 lux) affected the foraging behavior of the largest larvae (14-19 mm SL) especially at 10 lux where only one attack was observed with or without turbidity. The Horizontal attack angles (HRA) of larvae ranged from 0-114° with 78% of attacks taking place at angles between 20 and 70° while vertical reaction angles (VRA) of larvae ranged from 12-90° with 77% of attacks occurring at < 50°. The average length of the predation cycle decreased with increasing larval size from 2.4 s down to 1.34 s for larger larvae. Bay anchovy larvae frequently aborted attacks (33%) after reacting and approaching prey. Attack success was high even for small larvae (mean = 83%) and approached 100% in the largest size class.

Antioxidant and Adaptogenic Effect of an Herbal Preparation, Triphala

Objective: To investigate the antioxidant and adaptogenic activities of Triphala, an Indian Ayurvedic medicinal preparation. Materials and Methods: Antioxidant activity of Triphala was determined by hydroxyl and nitric oxide radical scavenging methods. Adaptogenic activity was studied using swim endurance, anoxic stress tolerance and chronic stress induced behavioral despair test models. Triphala was administered at the dosage levels of 100 to 500 mg/kg b.w.p.o. Results and Discussion: Triphala was found to scavenge hydroxyl and nitric oxide radicals in vitro . The IC 50 value for hydroxyl radical scavenging was 40.5 μg/mL and that for nitric oxide radical scavenging was found to be 40 μg/mL, respectively. Oral administration of Triphala formulation significantly improved the stress tolerance by increasing the swim duration (762.28 ± 7.17 minute), anoxic stress tolerance duration (39.11 ± 1.05 minute) and reduced the stress induced increase in the immobility period (61.11 ± 3.42 seconds) in chronic shock induced stress. Conclusion: Triphala has been found to be an excellent scavenger of hydroxyl radicals and nitric oxide radicals, whose excessive formation is implicated in oxidative stress. Triphala is capable of increasing the capacity to tolerate non-specific stress in experimental animals as evident from the restoration of parameters studied during different types of stress models.

Longer flumes increase critical swimming speeds by increasing burst–glide swimming duration in carp Cyprinus carpio, L.

Carp Cyprinus carpio altered the repertoire of swimming behaviour with increased flume length. While the transition speed from steady to burst–coast swimming was unaffected by flume length, fish reached higher critical swimming speed (Ucrit), consequently swimming for longer periods of time in burst–coast mode and hence performing more work before becoming fatigued. Analysis of swimming behaviour of burst–coast swimming revealed an increase in duration and a decrease in distance of forward burst movements with increasing water speeds. Frequency was unaffected by water speed. Overall, longer flumes increased Ucrit by allowing for less restricted burst–coast swimming behaviour.

Self-rescue swimming in cold water: the latest advice

According to the 2006 Canadian Red Cross Drowning Report, 2007 persons died of cold-water immersion in Canada between 1991 and 2000. These statistics indicate that prevention of cold-water immersion fatalities is a significant public health issue for Canadians. What should a person do after accidental immersion in cold water? For a long time, aquatic safety organizations and government agencies stated that swimming should not be attempted, even when a personal flotation device (PFD) is worn. The objective of the present paper is to present the recent scientific evidence making swimming a viable option for self-rescue during accidental cold-water immersion. Early studies in the 1960s and 1970s led to a general conclusion that "people are better off if they float still in lifejackets or hang on to wreckage and do not swim about to try to keep warm". Recent evidence from the literature shows that the initial factors identified as being responsible for swimming failure can be either easily overcome or are not likely the primary contributors to swimming failure. Studies over the last decade reported that swimming failure might primarily be related not to general hypothermia, but rather to muscle fatigue of the arms as a consequence of arm cooling. This is based on the general observation that swimming failure developed earlier than did systemic hypothermia, and can be related to low temperature of the arm muscles following swimming in cold water. All of the above studies conducted in water between 10 and 14 degrees C indicate that people can swim in cold water for a distance ranging between about 800 and 1500 m before being incapacitated by the cold. The average swimming duration for the studies was about 47 min before incapacitation, regardless of the swimming ability of the subjects. Recent evidence shows that people have a very accurate idea about how long it will take them to achieve a given swimming goal despite a 3-fold overestimation of the absolute distance to swim. The subjects were quite astute at deciding their swimming strategy early in the immersion with 86% success, but after about 30 min of swimming or passive cooling, their decision-making ability became impaired. It would therefore seem wise to make one's accidental immersion survival plan early during the immersion, directly after cessation of the cold shock responses. Additional recommendations for self-rescue are provided based on recent scientific evidence.

Surface swimming behavior of the curculionid Ochetina uniformis Pascoe (Erirhininae, Stenopelmini) and Ludovix fasciatus (Gyllenhal) (Curculioninae, Erodiscini)

The swimming behavior exhibited by specimens of L. fasciatus and O. uniformis was analyzed frame-by-frame with video observation recorded with a digital camera, attached to a stereomicroscope. Adults of O. uniformis, an aquatic insect, swim with all three pairs of legs. During the process of swimming the majority of the abdomen and rostrum remain submerged, part of the fore and hind tibiae remain above the surface, while the mid tibiae remain submerged. The mesothoracic legs, during the power-stroke stage, provide the greatest thrust while the metathoracic legs provide the least forward propulsion. The prothoracic legs, extended forward, help to direct the swimming. The semi-aquatic specie L. fasciatus shows the same swimming style as O. uniformis, that is, with movement of all the three pairs of legs; the mesothoracic legs are responsible for the main propulsion. The insect body remains on the water surface during the process of swimming, while the legs remain submerged. Both species complete a swimming cycle in 0.33 and 0.32 seconds, respectively, with an average speed of 1.38 cm/s and a maximum and minimum swimming duration time of 11.15 and 5.05 minutes, respectively, for L. fasciatus. The swimming behavior exhibited by O. uniformis and L. fasciatus corresponds to the style known as a breast strokelike maneuver. This is the first record of this kind of swimming for both species here observed and increases to seven the number of genera of Curculionidae exhibiting this behavior.

A study for changing aspects of water polo games due to the changes in international rules in 2005

The FINA (Federation Internationale de Natation Amateur) has changed the international rules of water polo to make the water polo more attractive globally in 2005. Although a major change was expected in aspects of the games by adopting the revised rules, a verification how changed has not been done yet. Therefore, the purpose of this study is to evaluate the aspects of the games such as swimming distance, swimming velocity and time-motion analysis under a revised condition. The activities of 18 water-polo-players (6 center forwards, 6 drivers and 6 center backs) were videotaped and analyzed, in a total of five games of the Japan Swimming Championship which was held in the Tokyo Metropolitan Gymnasium from 29th June to 1st July in 2007. A two-dimensional DLT method was used to evaluate a position of player, swimming distance and swimming velocity by the Fame Dias II (DKH Cooperation). In addition the time-motion analysis was done to evaluate the game qualitatively. As results, an average of game duration was 48min 53second. An average of swimming distance of total is 1803.3 ± 137.8m. An average of swimming velocity of total is 0.65 ± 0.06m/s. It is revealed that the mean duration of contact was decreased, the mean duration of swimming was increased and the mean duration of vertical position was decreased. These results show that the intention with the revision of rules has been achieved.

Availability of dissolved organic matter offsets metabolic costs of a protracted larval period for Bugula neritina (Bryozoa)

For nearly a century researchers have investigated the uptake and utilization of dissolved organic matter (DOM) by marine invertebrates, but its contribution to their growth, reproduction, and survival remains unclear. Here, the benefit of DOM uptake was assessed for the marine bryozoan Bugula neritina (Linnaeus 1758) through performance comparisons of individuals in the presence and absence of DOM. The experiments were performed using B. neritina collected from floating docks in Beaufort, NC, USA from July to September 2004. Seawater was subjected to ultraviolet irradiation to reduce naturally occurring DOM, and then enriched with either 1 μM of palmitic acid or a mixture containing 1 μM each of glucose, alanine, aspartic acid and glycine. Larvae in DOM-enriched and DOM-reduced treatments were sampled and induced to metamorphose following 1, 6, 12, and 24 h of continuous swimming at 25°C. Sampled larvae were assessed for initiation of metamorphosis, completion of metamorphosis, and ancestrular lophophore size to determine the extent to which energy acquired from DOM uptake could offset the metabolic costs of prolonged larval swimming. DOM treatment had no significant effect on initiation of metamorphosis, but did have a significant effect on completion of metamorphosis and lophophore size. Larvae swimming in DOM-enriched treatments for 24 h experienced a 20% increase in metamorphic completion rate, compared to larvae swimming for 24 h in the DOM-reduced treatment. In addition, larvae in the amino acid and sugar mixture for 24 h had a significantly larger lophophore surface area and volume (23 and 31%, respectively), compared to larvae in DOM-depleted seawater. To ensure that the increases in performance found in larvae with access to DOM were not due to a decrease in metabolic activity, the respiration rates for these larvae were compared to those of larvae in DOM-depleted seawater. There were no significant differences between these treatments, indicating that the increases in performance were due to the energy acquired from DOM. These results clearly show that for B. neritina, DOM uptake results in increased metamorphic success and in the size of the feeding apparatus following an extended larval swimming duration.