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Nature sports include pursuits such as paragliding, white-water kayaking, free diving, mountaineering, and surfing. Participants in nature sports interact with geographical features (e.g. mountains, rivers, oceans, snow fields, ice sheets, caves, rock faces) as well as the dynamic forces that produce them (e.g. gravity, waves, thermal currents, flowing water, wind, rain, sun). In this article, I engage a representational approach to analyze how participants in nature sports interact with nature. Anthropocentric representations privilege participants' interests, wants, desires, and ends; they typically refer to claims of conquest/achievement in nature, or praise nature for its therapeutic qualities. In contradistinction, ecocentric representations recognize humankind as one entity in an interdependent world that comprises all living organisms and the geological processes and geomorphological features that sustain them. Ecocentric representations of nature sports highlight networks of participants and landforms that help preserve a balance between people and the environment. Yet, notwithstanding the allure of ecocentric representations, especially in the wake of evidence that human-induced greenhouse gases are predisposing environmental calamities, there is a substantial gap between the ontological concepts and categories of ecocentrism and lived sporting experiences and practices in nature. [ABSTRACT FROM AUTHOR]

Freediving (synonyms: breath-hold diving, apnea diving) has become a popular leisure activity and continues to gain popularity and recognition as both a competitive and recreational sport. Formal freediving competitions are sanctioned by the international Confédération Mondiale des Activités Subaquatiques (CMAS) or the Association Internationale pour le Développement de l'Apnée (AIDA). Both organizations have set up rules and guidelines for competitive pool disciplines where athletes compete for maximum submerged breath-hold time or underwater swimming distance with or without fins. › In freshwater disciplines athletes strive for maximum depth using different freediving techniques. These aquatic breath-holding activities carry unique medical risks that are related to environmental factors eliciting extreme physiological challenges. Pool disciplines carry an increased risk of hypoxemia and, consequently, loss of consciousness, particularly in untrained individuals. Hypoxic complications are reported to occur in up to 10% of dives during freediving competitions. Shallow water blackout following hyperventilation to extend breathhold capability is a serious risk applying to all aquatic breath-hold activities, however, is more common during recreational freediving. › Deep freediving poses the athlete to further risks such as barotrauma of ear drums or lungs, immersion pulmonary edema, nitrogen narcosis, and decompression sickness when reaching great depths. While serious complications in competitive freediving are rare, however, the risk clearly rises with increasing depth. Special breathing techniques to increase lung volumes such as glossopharyngeal insufflation carry additional risks. › This article reviews possible complications and injury that may occur in competitive freedivers and discusses strategies for management and prevention of possible injury. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effects of a five-week training program on undulatory underwater swimming (UUS) in swimmers and to compare the specific effects prompted by two different training protocols on UUS performance and kinematics. Swimmers (n = 14) were divided into in-water only (WO) (18.61 ± 2.62 years, FINA points: 507 ± 60) and water + dry-land training groups (with conical pulleys) (WD) (18.38 ± 2.67 years, FINA points: 508 ± 83). Three countermovement jumps (CMJ) and three maximal UUS trials were performed before and after a five-week training period. The training program comprised 14 × 30-min sessions. The WO group repeated the same 15-min block twice, while the WD group performed one block of 15 min in the water and the other block on land performing lower limb exercises with conical pulleys. Seven body landmarks were auto-digitalized during UUS by a pre-trained neural network and 21 kinematic variables were calculated. The level of statistical significance was set at p < 0.05. Significant time × group interaction in favour of the WD group was observed for mean vertical toe velocity (p = 0.035, η²p = 0.32). The WD group experienced enhancements in mean and maximum underwater velocity, kick frequency, maximum shoulder angular velocity, as well as mean and maximum vertical toe velocity (p < 0.05). The WO group exhibited an enhancement in CMJ height (p < 0.05). In conclusion, UUS performance was improved in adolescent swimmers after five weeks of specific training, only when combining water and conical pulley exercises. Coaches should include dry-land specific lower limb exercises in addition to in-water training to improve UUS performance. [ABSTRACT FROM AUTHOR]

This study investigates the impact of a five-week functional exercise intervention designed to enhance the muscular endurance of the posterior shoulder musculature, aiming to mitigate shoulder fatigue and overuse injury. Twelve Division I collegiate butterfly swimmers were recruited and evenly randomized into exercise (EX) and control (CTRL) groups. Weekly 100-yard butterfly sprints were performed, with Muscle Oxygen Saturation (SmO2) continuously monitored using a wearable near-infrared spectroscopy (NIRS) device. This study is among the first to utilize wearable NIRS devices to monitor SmO2 underwater during swimming, demonstrating that a targeted 5-week exercise program significantly improves posterior shoulder endurance, as evidenced by increased Posterior Shoulder Endurance Test (PSET) scores and distinctive SmO2 adaptations in the EX-group compared to the CTRL group. These findings suggest that targeted dryland exercises can enhance posterior shoulder endurance with long-term implications for potentially reducing injury risk and improving performance. [ABSTRACT FROM AUTHOR]

While researchers have made notable progress in bio-inspired swimming robot development, a persistent challenge lies in creating propulsive gaits tailored to these robotic systems. The California sea lion achieves its robust swimming abilities through a careful coordination of foreflippers and body segments. In this paper, reinforcement learning (RL) was used to develop a novel sea lion foreflipper gait for a bio-robotic swimmer using a numerically modelled computational representation of the robot. This model integration enabled reinforcement learning to develop desired swimming gaits in the challenging underwater domain. The novel RL gait outperformed the characteristic sea lion foreflipper gait in the simulated underwater domain. When applied to the real-world robot, the RL constructed novel gait performed as well as or better than the characteristic sea lion gait in many factors. This work shows the potential for using complimentary bio-robotic and numerical models with reinforcement learning to enable the development of effective gaits and maneuvers for underwater swimming vehicles. [ABSTRACT FROM AUTHOR]

Fish mass is important to optimize daily feeding, control stocking densities, and ultimately determine optimal harvest time. Currently fish mass mainly relies on manual measurements, which is not only time consuming and laborious but also brings stress to fish, and even causes death. However, fish different postures and tail deformation during swimming are challenging for binocular vision to precisely measure mass in unconstrained underwater environment. This study creatively introduces the angle between space vectors to select fish postures, and develop mass prediction model based on length of fish without tail fin. Firstly, three-dimensional coordinates of feature point obtained by convex hull algorithm are calculated by information fusion based on depth images and RGB images from instance segmentation. Secondly, the angle between fish body long axis and camera optical axis is first proposed to select good fish posture for length estimation. Finally, the relationship model between mass and length without considering tail fins is constructed, and subsequently this model has been tested on test datasets. We conducted experiments with Oplegnathus punctatus as an example, and experimental results show that the method can achieve non-contact precise measurement of underwater fish mass, which can be further used to estimate fish mass in densely breeding environment. [ABSTRACT FROM AUTHOR]

The corrosion behavior of novel MgO–Mg 1.08 Al 1.84 Ti 0.08 O 4 refractories was investigated as a potential replacement for traditional MgO–MgAl 2 O 4 refractories as the inner lining of RH snorkels. The incorporation of Mg 1.08 Al 1.84 Ti 0.08 O 4 fine powder with dense microstructure resulted in superior densification and mechanical strength compared to traditional MgO–MgAl 2 O 4 refractories. The novel MgO–Mg 1.08 Al 1.84 Ti 0.08 O 4 refractories significantly enhanced their corrosion resistance, due to the reduction in porosity and pore diameter, as well as the increase in pore complexity and contact angle. These factors effectively impeded the penetration of RH slag. Additionally, the presence of Mg 1.08 Al 1.84 Ti 0.08 O 4 in contact with RH slag formed a more complex (Mg, Fe)(Al, Ti) 2 O 4 spinel solid solution, which exhibited strong Fe element absorption ability. Thus, this decreased the Fe concentration in the RH slag, resulting in an increase in liquid slag viscosity and enhancing the slag penetration resistance of MgO–Mg 1.08 Al 1.84 Ti 0.08 O 4 refractories. The microstructure of the MgO–Mg 1.08 Al 1.84 Ti 0.08 O 4 refractories featured an isolated distribution of Ca 2 SiO 4 phase, which suggested fewer channels for liquid RH slag to penetrate the refractory materials. According to Factsage 6.2 thermodynamic simulation, the dissolution of Mg 1.08 Al 1.84 Ti 0.08 O 4 into liquid slag was lower compared to the sintered MgAl 2 O 4 , which was advantageous for resisting the dissolution of refractory materials into liquid slag. [ABSTRACT FROM AUTHOR]

Farmed salmon escaping from aquaculture and interbreeding with wild conspecifics pose a significant threat to the genetic integrity of natural salmon populations. Despite advancements in aquaculture security, escape incidents persist, prompting the need for effective mitigation strategies. This study summarizes experiences from efforts to remove escaped farmed salmon over a 12-year period in 63 western Norwegian rivers, using either (1) spearfishing during snorkelling by trained personnel or (2) traditional fishing methods employed by local groups. Recaptured farmed salmon ranged widely in size and included both spawners as well as immature fish, demonstrating that farmed fish entering rivers comprise fish of different ages and escape histories. Traditional fishing by locals recaptured the highest number of farmed fish, while removal during snorkelling in general captured larger and mature fish. On average, 53% of the farmed salmon observed during snorkelling were recaptured. This efficacy was influenced by the number of farmed fish present and the size of the farmed fish. In addition, efficacy increased over time, indicating that the removal team became more efficient. The study underscores that active removal, when executed judiciously, contributes to reducing the ecological risks associated with escaped farmed fish, complementing broader strategies for sustainable aquaculture. [ABSTRACT FROM AUTHOR]

Despite elite human free divers achieving incredible feats in competitive free diving, there has yet to be a study that compares consummate divers, (i.e. northern elephant seals) to highly conditioned free divers (i.e., elite competitive free-diving humans). Herein, we compare these two diving models and suggest that hematological traits detected in seals reflect species-specific specializations, while hematological traits shared between the two species are fundamental mammalian characteristics. Arterial blood samples were analyzed in elite human free divers (n = 14) during a single, maximal volitional apnea and in juvenile northern elephant seals (n = 3) during rest-associated apnea. Humans and elephant seals had comparable apnea durations (∼6.5 min) and end-apneic arterial P o 2 [humans: 40.4 ± 3.0 mmHg (means ± SE); seals: 27.1 ± 5.9 mmHg; P = 0.2]. Despite similar increases in arterial P co 2 (humans: 33 ± 5%; seals: 16.3 ± 5%; P = 0.2), only humans experienced reductions in pH from baseline (humans: 7.45 ± 0.01; seals: 7.39 ± 0.02) to end apnea (humans: 7.37 ± 0.01; seals: 7.38 ± 0.02; P < 0.0001). Hemoglobin P50 was greater in humans compared to elephant seals (29.9 ± 1.5 and 28.7 ± 0.6 mmHg, respectively; P = 0.046). Elephant seals overall had higher carboxyhemoglobin (COHb) levels (5.9 ± 2.6%) compared to humans (0.8 ± 1.2%; P < 0.0001); however, following apnea, COHb was reduced in seals (baseline: 6.1 ± 0.3%; end apnea: 5.6 ± 0.3%) and was slightly elevated in humans (baseline: 0.7 ± 0.1%; end apnea: 0.9 ± 0.1%; P < 0.0002, both comparisons). Our data indicate that during static apnea, seals have reduced hemoglobin P50, greater pH buffering, and increased COHb levels. The differences in hemoglobin P50 are likely due to the differences in the physiological environment between the two species during apnea, whereas enhanced pH buffering and higher COHb may represent traits selected for in elephant seals. NEW & NOTEWORTHY: This study uses similar methods and protocols in elite human free divers and northern elephant seals. Using highly conditioned divers (elite free-diving humans) and highly adapted divers (northern elephant seals), we explored which hematological traits are fundamentally mammalian and which may have been selected for. We found differences in P50, which may be due to different physiological environments between species, while elevated pH buffering and carbon monoxide levels might have been selected for in seals. [ABSTRACT FROM AUTHOR]

Anoplodactylus arescus du Bois-Reymond Marcus, 1959, was first recorded and described from the northern Red Sea. New material was collected from soft bottom substrates spanning Hurghada to Halayeb from 2019 to 2020. The collection sites varied in depth, ranging from intertidal to 35 meters deep. The intertidal sand samples were manually collected during snorkeling, while the deep samples required SCUBA diving for collection. Pycnogonid fauna were isolated, sorted, counted, and then identified to the lowest taxonomic level. The results revealed Anoplodactylus arescus as abundant species among the seven study areas selected. Grain size analysis was conducted at each site to evaluate its effect on the pycnogonid distribution. A list of species of pycnogonids reported from the Red Sea was provided based on our collection and approved literature. The results revealed a diverse community of pycnogonids in the Red Sea, with 17 species identified, belonging to nine genera and eight families. The study further indicates that coarse and medium sand, ranging from 125- 500µm, provides a suitable substrate for Anoplodactylus arescus. Pycnogonids were found in lower densities out of this grain size range. [ABSTRACT FROM AUTHOR]

Predator avoidance is critical to fish survival and yet multiple types of predator response are rarely recorded at the level of individuals let alone studied in detail. Behaviour of an individual adult male dragonet, Gross's stinkfish Callionymus grossi (Ogilby 1910) (Family Callionymidae) was observed over the course of four consecutive daily snorkelling sessions on high tides in the Maroochy River estuary, Queensland, Australia. On two occasions, the dragonet buried in the sand in the presence of a great barracuda, Sphyraena barracuda, whereas, smaller benthic predators or competitors and the observer sometimes provoked dorsal fin raising and fleeing responses of the dragonet. The dragonet, therefore, demonstrates multiple responses to potential predators and competitors seemingly depending on the likely severity of interaction. Further research of dragonet fishes is recommended to disentangle the functionality of fin display in this group, with the anti‐predator function of fin displays and honest signalling of chemical defence a promising aspect for investigation. [ABSTRACT FROM AUTHOR]

The present study discusses the numerical simulation results of swimming similar to manta rays. The complex three-dimensional kinematics of manta rays were implemented to unravel the intricacies of its propulsion mechanisms by using the discrete vortex method (DVM). The DVM replaces the requirement for a structured grid across the computational domain with a collection of vortex elements. This method simplifies grid generation, especially for intricate geometries, resulting in time and effort savings in meshing complex shapes. By modeling the pectoral fins with discrete panels and utilizing vortex rings to represent circulation and wake, the study accurately computes the pressure distribution, circulation distribution, lift coefficient, and thrust coefficient of the manta ray. This study focuses on the modulation of aerodynamic performance by altering the span length and the length change ratio during the downstroke and upstroke motion ( S V ). The manta ray's three-dimensional vortex configurations comprise a combination of vortex rings, vortex contrails, and horseshoe vortices. Analysis of the three-dimensional vortex structure indicates the presence of multiple vortex rings and horseshoe vortex rings at higher S V values, while adequate formation of horseshoe vortices is not observed at lower S V values. In terms of propulsive performance, both lift and thrust increase with S V , while the propulsive efficiency demonstrates its peak at S V = 1.75. The analysis reveals that at higher S V values, the net thrust generated primarily originates from the tip of the fins. Moreover, the study illustrates a significant enhancement in propulsive efficiency, particularly in association with optimal Strouhal numbers ranging between 0.3 and 0.4. The key findings of this study may be used in efficient design of agile autonomous underwater vehicles for marine exploration and surveillance applications. [ABSTRACT FROM AUTHOR]

This work addresses the lack of reliable wearable methods to assess walking gaits in underwater environments by evaluating the lateral hydrodynamic pressure exerted on lower limbs. Sixteen healthy adults were outfitted with waterproof wearable inertial and pressure sensors. Gait analysis was conducted on land in a motion analysis laboratory using an optoelectronic system as reference, and subsequently underwater in a rehabilitation swimming pool. Differences between the normalized land and underwater gaits were evaluated using temporal gait parameters, knee joint angles and the total water pressure on the lower limbs. The proposed method was validated against the optoelectronic system on land; gait events were identified with low bias (0.01s) using Bland-Altman plots for the stride time, and an acceptable error was observed when estimating the knee angle (10.96° RMSE, Bland-Altman bias -2.94°). The kinematic differences between the land and underwater environments were quantified, where it was observed that the temporal parameters increased by more than a factor of two underwater (p<0.001). The subdivision of swing and stance phases remained consistent between land and water trials. A higher variability of the knee angle was observed in water (CV = 60.75%) as compared to land (CV = 31.02%). The intra-subject variability of the hydrodynamic pressure on the foot (CVzfoot = 39.65%) was found to be substantially lower than that of the knee angle (CVz = 67.69%). The major finding of this work is that the hydrodynamic pressure on the lower limbs may offer a new and more reliable parameter for underwater motion analysis as it provided a reduced intra-subject variability as compared to conventional gait parameters applied in land-based studies. [ABSTRACT FROM AUTHOR]

The surge of e-commerce reviews has presented a challenge in manually annotating the vast volume of reviews to comprehend their underlying aspects and sentiments. This research focused on leveraging weakly supervised learning to tackle aspect category learning and the sentiment classification of reviews. Our approach involves the generation of labels for both aspects and sentiments, employing the Snorkel framework of WSL, which incorporates aspect terms, review sentiment scores, and review ratings as sources of weak signals. This innovative strategy significantly reduces the laborious labeling efforts required for processing such extensive datasets. In this study, we deployed hybrid models, namely BiLSTM, CNN-BiLSTM, and CNN-LSTM, which harness multiple inputs, including review text, aspect terms, and ratings. Our proposed model employs two distinct loss functions: Binary Cross Entropy with Sigmoid Activation for Multi-Label Classification, enabling us to learn aspect Labels such as Quality, Usability, Service, Size, and Price, and Categorical Cross Entropy with Softmax Activations for Multi-Class Classification. Subsequently, we meticulously evaluate the performance metrics of these three implemented models, including Macro F1 score and Macro Precision. CNN & Bi-LSTM model attained 0.78 and 0.79 F1 scores on aspect and sentiment identification, respectively. The outcomes of this research are poised to make a substantial contribution to e-commerce platforms, offering an efficient and automated means to label and analyze vast troves of user reviews. [ABSTRACT FROM AUTHOR]

The study objective was to evaluate human faecal contamination impacts in the Yal-ku lagoon in the Mexican Caribbean and to estimate adenovirus infection and illness risks associated with recreational exposure during water activities. A total of 20 water samples (10 from each site × two sites) (50 L) were collected monthly over a period of 12 months from two selected sampling sites in the swimming area of the Yal-ku lagoon. The occurrence of faecal-associated viruses was explored, and human adenovirus (HAdV) and pepper mild mottle virus (PMMoV) concentrations were quantified. A quantitative microbial risk assessment (QMRA) model was used to estimate exposure and subsequent adenovirus infection and illness risk for 1 h of swimming or snorkelling. Somatic and Fþ -specific coliphages occurred in 100% of the samples. Both HAdV and PMMoV were detected at a 60% frequency thereby indicating persistent faecal inputs. PMMoV concentrations (44-370 GC/L) were relatively lower than the concentrations of HAdV (64-1,000 GC/L). Estimated mean adenovirus risks were greater for snorkelling than for swimming by roughly one to two orders of magnitude and estimated mean illness risks for snorkelling were .32/1,000. Human faecal contamination is frequent in the Yal-ku lagoon, which is associated with human gastrointestinal illness. [ABSTRACT FROM AUTHOR]

The most challenging task in the decommissioning of the Fukushima Daiichi Nuclear Power Station is to retrieve molten and solidified fuel debris, including in reactor internals. The International Research Institute for Nuclear Decommissioning (IRID) has developed various robots that can investigate the interior of a primary containment vessel (PCV) to clarify where fuel debris has accumulated and how it has formed. The scenarios of each unit caused by the accident are different; therefore, IRID has developed robots to satisfy the requirements of each unit. The robots can be categorized into three types: non-submersible robots driving through air, submersible robots swimming underwater, and investigation robots with arms that can extend to enter the PCV. This review focuses on the technological development of robots based on their functionality. Most of the robotic technology is acquired and utilized based on the results of subsidy projects for countermeasures for decommissioning and contaminated water granted by the Japanese government. [ABSTRACT FROM AUTHOR]

Introduction: Air flow in full-face snorkel masks (FFSMs) should be unidirectional to prevent rebreathing of exhaled air. This study evaluated rebreathing and its consequences when using FFSMs compared to a conventional snorkel. Methods: In a dry environment 20 participants wore three types of snorkel equipment in random order: Subea Easybreath FFSM; QingSong 180-degree panoramic FFSM; and a Beuchat Spy conventional snorkel (with nose clip), in three conditions: rest in a chair; light; and moderate intensity exercise on a cycle ergometer. Peripheral oxygen saturation, partial pressure of carbon dioxide (PCO2) and oxygen (PO2) in the end tidal gas and FFSM eye-pockets, respiratory rate, minute ventilation, were measured continuously. Experiments were discontinued if oxygen saturation dropped below 85%, or if end-tidal CO2 exceeded 7.0 kPa. Results: Experimental runs with the FFSMs had to be discontinued more often after exceeding 7.0 kPa end-tidal CO2 compared to a conventional snorkel e.g., 18/40 (45%) versus 4/20 (20%) during light intensity exercise, and 9/22 (41%) versus 3/16 (19%) during moderate intensity exercise. Thirteen participants exhibited peripheral oxygen saturations below 95% (nine using FFSMs and four using the conventional snorkel) and five fell below 90% (four using FFSMs and one using the conventional snorkel). The PCO2 and PO2 in the eye-pockets of the FFSMs fluctuated and were significantly higher and lower respectively than in inspired gas, which indicated rebreathing in all FFSM wearers. Conclusions: Use of FFSMs may result in rebreathing due to non-unidirectional flow, leading to hypercapnia and hypoxaemia. [ABSTRACT FROM AUTHOR]

Sabbaticals have seen an exponential growth in adoption over the last two decades and are ascribed extensive benefits by employers and employees alike. Little is known, however, about how individuals spend their time or how their experiences impact them after they return to work. Drawing on narrative interviews with 50 diverse professionals, we discover that sabbaticals combine "building blocks"− distinct periods dedicated to recover, explore, or practice− into three typical trajectories: working holidays (alternating recovery and practice), free dives (alternating recovery and exploration), and quests (unfolding from recovery to exploration to practice). While participants returned from all sabbaticals feeling affirmed in their own voice, periods of exploration and practice were associated with the extent to which sabbaticals fundamentally changed their self-narrative and disrupted the trajectory of their working lives. Those on working holidays tended to return to their former lives (though with a greater confidence and need for balance), while free divers pursued better fitting but similar work (e.g., a change in position or employer), and questers were most likely to make drastic career changes. Our model extends the breaks literature and authenticity scholarship, and offers insights to those considering a sabbatical. [ABSTRACT FROM AUTHOR]

Undulatory swimming is the predominant form of locomotion in aquatic vertebrates. A myriad of animals of different species and sizes oscillate their bodies to propel themselves in aquatic environments with swimming speed scaling as the product of the animal length by the oscillation frequency. Although frequency tuning is the primary means by which a swimmer selects its speed, there is no consensus on the mechanisms involved. In this article, we propose scaling laws for undulatory swimmers that relate oscillation frequency to length by taking into account both the biological characteristics of the muscles and the interaction of the moving swimmer with its environment. Results are supported by an extensive literature review including approximately 1200 individuals of different species, sizes and swimming environments. We highlight a crossover in size around 0.5–1 m. Below this value, the frequency can be tuned between 2–20 Hz due to biological constraints and the interplay between slow and fast muscles. Above this value, the fluid-swimmer interaction must be taken into account and the frequency is inversely proportional to the length of the animal. This approach predicts a maximum swimming speed around 5–10 m.s−1 for large swimmers, consistent with the threshold to prevent bubble cavitation. Mechanisms by which aquatic animals optimize their tailbeat frequency for swimming have not been fully explained. Here, the authors propose scaling laws for undulatory swimmers, relating beat frequency to length considering muscle biology and fluid interaction. [ABSTRACT FROM AUTHOR]

The article "Freediving - from Tradition to Modernity" explores the transition of freediving from a traditional practice to a modern sport. It discusses the historical roots of freediving, physiological adaptations required for the sport, and recent developments in training methods and scientific research. The text also delves into the physiological mechanisms involved in deep diving, cardiac stress during apnea diving, and potential risks such as inert gas narcosis and decompression illnesses. Overall, the article provides a comprehensive overview of the evolution and challenges of freediving as a sport. [Extracted from the article]

The central objective lies in synthesizing the use of cc and land by tourists and service providers. The methodology used was analytical of the information obtained in the cabinet and enriched with field work on the island of La Roqueta in Acapulco de Juárez, Guerrero, Mexico during the Easter and summer vacation periods from 2020 to August 2022. Between the results are: a) the seawater, being crystalline, warm, with little waves, makes free diving (snorkeling) and autonomous diving (scuba) possible and b) the ground that has contact with the seawater has fine-textured sand, beige color, average height of three meters where swimming activities, walks, among others, take place. The conclusions are: 1) extensive use of seawater for intensive tourist use and 2) the sandy soil supports four on-site restaurants. [ABSTRACT FROM AUTHOR]

There is a growing trend towards studying human cognition in aquatic environments. At present, there exists a dearth of scholarly investigations pertaining to the immediate effects on executive functions subsequent to a solitary breath-holding training session within the cohort of professional free divers who engage in highly strenuous activities that test their physiological boundaries. The objective of this study was to investigate the immediate impact of breath-holding exercises conducted in varying environments (water and land) on the executive functions of professional diving athletes. The research comprised a sample of 18 male individuals engaged in competitive free diving. The experimental design encompassed four distinct sessions: i) an initial phase dedicated to familiarising participants with the N-back test; ii) a subsequent phase involving the collection of baseline and control measurements for the N-back test; iii) a session focused on obtaining anthropometric measurements; and iv) a final session dedicated to measuring lung capacity. The cognitive assessments were conducted subsequent to the breath-holding exercise protocol, which occurred subsequent to both the land and water sessions. The results indicated a significant difference in reaction times between breath-holding exercises conducted on land and in water (p =.021). The computation of delta values was employed to ascertain alterations in cognitive test outcomes under distinct conditions (water and land) in comparison to the control condition. The findings revealed a statistically significant decline in cognitive performance in the water condition relative to the land condition (z:- 2.025, p= 0.043, r= -0.544). This study claims that the implementation of breath-holding exercise training in surface water conditions among divers could potentially result in adverse effects on executive functions. Moreover, it has been observed that the identical breath-holding exercises, when executed in terrestrial environments, exhibit a moderate enhancement of executive functions. The present study posits that the aforementioned findings will make a valuable contribution to the development of training methodologies for athletes and coaches involved in the discipline of freediving. Additionally, these findings are anticipated to offer valuable insights into the physiological well-being of divers. [ABSTRACT FROM AUTHOR]

Snorkeling is one of the leading causes of marine environmental degradation in coastal destinations around the world, and tourists' irresponsible behavior is a major contributor. The development of environmentally responsible behavior among tourists has thus become critical in preventing and mitigating marine and coastal natural resource problems. Using the extended theory of planned behavior (TPB), this study aims to explore factors influencing tourists' environmentally responsible behavior. The study was conducted from June 1 to December 30, 2022, with 520 participants in Mu Koh Lanta and Hat Chao Mai Marine National Parks, Thailand. Self-administered questionnaires were used to collect the data. The collected data were analyzed by using SEM. The empirical findings show that extended TPB with sociopsychological components (such as environmental concern, environmental attitude, subjective norm, environmentally responsible behavioral intentions) and socioenvironmental factors (environmental knowledge) can explain tourists' environmentally responsible behavior. [ABSTRACT FROM AUTHOR]

The effects of pre-activation exercises on undulatory underwater swimming (UUS) have not been studied. This research aimed to: 1) assess the effects of a jumping-exercise strategy upon UUS performance and kinematics variables; 2) test the different effects on males and females, and; 3) to explore if stronger participants exhibit greater post-activation performance enhancement (PAPE). Ninety-two age-group national level swimmers randomly assigned into control (17 males and 18 females) and experimental groups (27 males and 30 females) took part in a cross-sectional study designed to test two maximal 15-m UUS performance efforts. The experimental group performed four maximal tuck jumps before the first or the second UUS effort. Performance and kinematics variables were analyzed using instantaneous velocity data via speedometer. Maximal lower-limbs force was obtained during a countermovement jump through a linear-encoder. Two-way repeated measures ANOVA test and linear regression analysis were used to explore variable interactions between baseline and PAPE, and the association between the PAPE response and strength of the swimmers, respectively. Despite trends toward improvements in push-off velocity (Δ = 1.33%; d = 0.12), the results did not show enhancements nor deterioration in UUS performance and kinematics after the tuck jumps. No specific PAPE responses modulated by sex or by the strength level of the swimmers were observed for this age-group (p < 0.05). Four tuck jump repetitions executed prior to diving could be insufficient to acutely enhance UUS performance. The fact that the exercise performed during warm-up was a body-weight based exercise, was possibly not enough to evoke PAPE. [ABSTRACT FROM AUTHOR]

Snorkel snails (genus Rhiostoma) are widely distributed in Indo-China and on the Malay Peninsula. The shell morphology is traditionally used for species identification yet in Thailand, the common snorkel snail, Rhiostoma housei , shows considerable variation in shell morphology within and between populations. Therefore species identifications and delimitations are difficult. We used two mitochondrial DNA fragments (COI and 16S rRNA) and morphological characters to delimit species and infer phylogenetic relationships of Rhiostoma housei s.l. from eight localities in Thailand, representing potential cryptic species suggested by earlier allozyme and karyological data. Results revealed four distinct clades from different geographic areas in Thailand. Species delimitation analyses confirmed the clades as four separate species and a geometric morphometric analysis demonstrated subtle but consistent conchological differences between the four clades. The high COI sequence divergences among the four clades (mean: 14.8%; range: 10.3–16.5%) further supported the species level recognition. As a consequence, three new species are described from Thailand: R. khoratense , sp. nov., R. nakwangense , sp. nov. and R. phunangense , sp. nov. ZooBank: urn:lsid:zoobank.org:pub:EE534749-9346-4972-BF2E-3B5D0EB8AED8 Snorkel snails of the genus Rhiostoma have considerable variation in shell morphology. We used two mtDNA fragments, morphological characters and shell geometric morphometrics to infer phylogenetic relationships. Results revealed four distinct clades and four separate species under the name R. housei. [ABSTRACT FROM AUTHOR]

A snorkel mask with a 3D-printed adaptor to HEPA filter was used in a COVID-19 emergency ward to provide safe respiratory support The Molinari connector allowed 30 patients in this study, and almost 100 patients afterwards to receive respiratory support during the pandemic. Noninvasive positive pressure ventilation (NIPPV) devices can generate aerosols spreading the virus in hospital wards. [Extracted from the article]

With the increasing requirements of underwater missions and the rapid development of soft robotics technologies, soft underwater swimming robots have become a hot topic of research due to their low noise, high flexibility, and high environmental adaptability. In the past 10 years, research into soft underwater robots based on artificial muscle actuation has made considerable progress. Herein, a comprehensive survey on recent advances in soft underwater swimming robots based on different actuation methods is reviewed systematically, including pressure actuation, intelligent material actuation, and biomaterial actuation. First, for each type of actuation, the actuating principle, structural design, and swimming performance of soft underwater robots are introduced in detail. Then, according to the different swimming modes of underwater organisms, the aforementioned soft underwater robots are classified and compared. The results show that for different swimming tasks and application scenarios, the robot needs to realize the optimal design by reasonably selecting the actuating method and the swimming mode. This review summarizes the advanced information and critical technology in designing high‐performance soft underwater robots in the aspect of structural design, actuating methods, and swimming modes and offers an insightful outlook for the future development of soft robots. [ABSTRACT FROM AUTHOR]

Single Snorkel Furnace (SSF) vacuum refining furnace is a novel external refining equipment for high clean steel production. RH is a molten steel refining technology developed by Rheinstahl-Heraeus company. Compared with the traditional RH furnace, the SSF furnace has the advantages of a simple structure, high refining efficiency, and low production cost. However, because the upward flow and the downward flow are in a single snorkel, the flow phenomenon is more complex than that in the RH device. Therefore, the gas–liquid two-phase flow law in SSF furnaces plays an important role in improving equipment efficiency and accurate control. In addition, the evolution and movement behavior of bubbles have an important influence on the two-phase flow. In this study, the Population Balance Model (PBM) model is employed to study the bubble properties, taking into account the effect of bubble coalescence and breakup on the flow field. The simulation results with this model are consistent with the experimental values, and the comparison with the results of the model without the PBM is revealed to be closer with less error. The results show that with the PBM model the flow field is more homogeneously distributed, the flow velocity is more stable, and the area distribution of the upward flow and downward flow in the snorkel is more symmetrical. In the case of this study, as the fluid level rises, the bubble diameter will increase due to the decrease in hydrostatic pressure. [ABSTRACT FROM AUTHOR]