The Human Dive Reflex During Consecutive Apnoeas in Dry and Immersive Environments: Magnitude and Synchronicity

Introduction: The human dive reflex (HDR), an O2 conserving reflex, is characterised by an interplay of central parasympathetic and peripheral sympathetic reactions, which are presumed to operate independently of each other. The HDR is fully activated during apnoea with facial immersion in water and complete immersion in water is thought to increase the magnitude of HDR during consecutive apnoeas. A comparison of HDR activity between consecutive apnoeas in full-body immersion with consecutive apnoeas in dry conditions has not been fully explored. Also, the interplay between parasympathetic and sympathetic reactions involved in the HDR has not been thoroughly analysed.Methods: 11 human volunteers performed 3 consecutive 60 s apnoeas with facial immersion in dry conditions (FIDC) and 3 consecutive apnoeas with facial immersion in full immersion (FIFI). Heart rate (HR), R-R interval (RRI), finger pulse amplitude (FPA), splenic width (SW) and SpO2 were all measured before, during and after apnoeas. A one-way ANOVA using Dunn’s post hoc test was performed to assess HDR activity, and a Pearson’s correlation test was performed to assess HDR synchronisation between physiological parameters during both conditions.Results: Although HDR activity was not significantly different between both conditions, HR and RRI showed progressively greater changes during FIFI compared with FIDC, while SW and FPA changes were relatively equivalent. During FIDC, significant correlations were found between SW & SpO2 and FPA & SpO2. During FIFI, significant correlations were found between RRI & FPA, SW & FPA, HR & SpO2 and FPA & SpO2.Discussion: While there was no significant difference found between HDR activity during FIDC and FIFI, consecutive apnoeas during FIFI triggered a greater magnitude of cardiac activity. Furthermore, significant correlations between RRI and SW with FPA indicate a crosstalk between parasympathetic tone with splenic contraction and increased peripheral sympathetic outflow during FIFI compared to FIDC. In conclusion, HDR activity during consecutive apnoeas does not differ between FIDC and FIFI. There appears to be however a greater level of synchronicity during apnoeas in FIFI compared to FIDC and that this is most likely due to the physiological effects of immersion, which could induce neural recruitment and increased cross talk of HDR pathways.

Research and Engineering Application of Salt Erosion Resistance of Magnesium Oxychloride Cement Concrete

Aiming at the problem that ordinary cement concrete is subjected to damage in heavy saline soil areas in China, a new type of magnesium oxychloride cement concrete is prepared by using the gelling properties of magnesium oxychloride cement in this study, and the erosion resistance of the synthesized magnesium oxychloride cement concrete in concentrated brine of salt lakes is studied through the full immersion test. The effects of concentrated brine of salt lakes on the macroscopic, microscopic morphology, phase composition and mechanical properties of magnesium oxychloride cement concrete are investigated by means of macro-morphology, erosion depth, SEM, XRD and strength changes. The salt erosion resistance mechanism of magnesium oxychloride cement concrete is revealed. The results demonstrate that under the environment of full immersion in concentrated brine of salt lakes, there is no macroscopic phenomenon of concrete damage due to salt crystallization, and the main phase composition is basically unchanged. The microscopic morphology mostly changes from needle-rod-like to gel-like. Due to the formation of a new 5·1·8 phase on the surface layer and the increase in compactness, its compressive strength has a gradual increase trend. Based on the engineering application of magnesium oxychloride cement concrete, it is further confirmed that magnesium oxychloride cement concrete has excellent salt erosion resistance and good weather resistance, which provides theoretical support for future popularization and application.

VIRTUAL REALITY IN TEACHING OF FOREIGN LANGUAGES

The study of the mechanisms of language and speech abilities has shown that the most effective method of learning a foreign language is the method of full immersion, since students enter the natural language environment and are in it constantly. But the learning process in the classroom, no matter how organized and communicative it may be, cannot replace the real teaching experience. Since the most important factors for effective learning of a foreign language are the language environment and motivation, therefore, the development of new motivational language learning environments, including virtual reality (VR), is the main elements of the learning process. In such an educational space, virtual reality helps students to understand phenomena and situations that cannot be understood and explained using traditional methods in order to become part of the real world through modeling. In general, virtual reality is an ideal learning environment, and the possibilities of its technologies for learning have an extremely high potential for application

Respon Genotipe Padi Lokal terhadap Cekaman Rendaman di Pembibitan

Uncertain climate change impacts the difficulty of predicting the intensity of floods that hit rice fields in flood-prone areas, both the duration of the submerged plants and the height of the water surface. In order to evaluate the tolerance level and response of several local rice genotypes to submersion stress in the vegetative phase, 50 rice genotypes were screened (47 North Sumatran local varieties, 3 VUB), using special ponds to simulate flooding or inundation stress. The study used a separate plot design with three replications; the main plot was three immersion models, namely full immersion, partial soaking, and not soaking, and subplots of 50 rice genotypes. The immersion treatment was defined as a different growing environment. The results showed that in the fully submerged treatment, the recovery capacity of local rice plants only ranged from 0-20%. The new, improved varieties tested were Inpari 4 (susceptible), Inpari 3, 10, Ciherang, Inpara 2 (very susceptible), Inpari 30, FR13A (very tolerant). Submersion tolerant genotypes had a slight increase in plant height after being fully submerged. The chlorophyll content in the leaves decreased immediately after the soaking stress period (14 DAP) in all rice genotypes. The local rice genotypes tested were very susceptible to immersion; the new superior variety Inpari 4 was categorized as susceptible, while Inpari 30 and FR13A were very tolerant.

“The lantern of the world rises to mortals by varied paths”: Paul Laffoley (1935–2015) and Dante

American artist and architect Paul Laffoley (1935–2015) had a life-long fascination with Dante. Not only did he refer to Dante and the Commedia throughout his writings and paintings, but he created a large-scale triptych illustrating the poem, as well as sketched out plans for a full-immersion Dante study center on a planetoid orbiting the Sun, complete with a to-scale replica of the medieval Earth, Mount Purgatory, the material heavens, and the Empyrean through which a “Dante Candidate” could re-enact the Pilgrim’s journey. Laffoley’s work is often placed by art critics within the visionary tradition and Laffoley himself embraced that label, even as he deconstructed the term in his writing. Among the many visionary artists, poets, and philosophers Laffoley studied, Dante was central. He was, for Laffoley, a model seeker of knowledge, a seer beyond the illusions of everyday life. The essay that follows offers a brief biography of Laffoley and his works; an overview of his two main Dante projects ( The Divine Comedy triptych [1972–1975] and The Dantesphere [1978]); and initial considerations on how Dante’s works and thought fit into Laffoley’s larger epistemological project.

Architecture and planning of sports centers of football academies in the largest cities

Purpose: The article describes the principles of territorial placement of children's and youth football academies in the largest cities.Design/methodology/approach: The architectural and planning organization of football academies, which are the most important component of the professional training of football players in football clubs. The principles of the academy formation as a multifunctional center with a full immersion of students in the educational process. The relevance and need for the appearance of such football academies in the largest cities of Russia.Research findings: The inclusion of football academies in the largest cities is identified, the main types of training are determined, based on the analysis of such facilities in Russia, Europe and South America.Practical implications: The youth football academies can be arranged on the city periphery.

Kaiako and stakeholders’ perceptions about Māori partial-immersion environments' contribution to Māori-medium education

The contributions partial-immersion Māori programmes offer to the wider educational landscape of Aotearoa is essential to Māori achieving as Māori. In this article, partial-immersion settings are defined as Level 2 immersion (51%–80% te reo Māori instruction) and Level 3 immersion (31%–50% te reo Māori instruction). While lower levels of immersion can be less effective for language acquisition than full-immersion Māori environments (May et al., 2004), this study finds that partial-immersion programmes are perceived to produce beneficial outcomes in terms of ahurea tuakiri and culturally empowering practice.

An equilibrium desorption model for the strength and extraction yield of full immersion brewed coffee

The sensory qualities of brewed coffee are known to be strongly correlated with the total dissolved solids (TDS) and extraction yield (E) of the brew. Here, we derive a predictive model for the TDS and E of full immersion brewed coffee using a pseudo-equilibrium desorption approach. Assuming a single, species-averaged equilibrium constant $$K$$ K yields theoretical predictions indicating that the TDS is approximately inversely proportional to the water/coffee mass brew ratio, while E is independent of the brew ratio. Our experimental results strongly accord with both theoretical predictions, and indicate that E is approximately 21% over a wide range of brew ratios. An analysis of the standard oven-drying method for measuring E indicates that it yields significant underestimates of the true value at equilibrium, due to retained brew within the spent moist grounds. We further demonstrate that $$K$$ K is insensitive to grind size, roast level, and brew temperature over the range 80–99 °C. Taken together, our results indicate that full immersion brewing offers precise control over the TDS at equilibrium but little control over E, and that practitioners should pay careful attention to their brew ratio as the most important parameter for full-immersion brewing.

Gastronomic Tourism as a Way of Forming Impressions

Since the second half of the 2000s, gastronomic tourism has been the most dynamically growing segment of tourism around the world: up to 1/3 of the tourist’s expenses in the destination are expenses for food and beverage. The importance of gastronomy in the context of the experience economy has grown many times: gastronomy has ceased to be only a function of ensuring the tourist’s stay in the destination, along with accommodation and transport – it becomes the core of the tourist experience, a means of penetrating the history and culture of the destination, receiving the brightest and deepest emotions. Against the background of increasing globalization and ever-greater “seen” by the average tourist, there is a burning out of interest in traditional tourist activities; for example, sightseeing is no longer enough, and tourists require full immersion in the culture of the host country/region, and even more – they want to live a small life like a local, and gastronomic experiences that extend beyond the simple consumption of food are able to meet this exacting demand. The increasing tourist flows and the volume growth of public catering indicate the demand for the gastronomic component of tourism, which, in turn, can be one of the main ways to form impressions.