Fluid Intake and Hydration Responses to Mass Participation Gravel Cycling

Gravel cycling is a relatively new cycling discipline, with the Union Cycliste Internationale (UCI) hosting their first UCI Gravel World Championships in 2022. Gravel races combine features of road racing, cyclocross, and mountain biking, including various terrain of varying technical difficulty (paved roads, dirt roads, fire roads, single- and double-track trails), long distances, substantial vertical elevation gain, obstacles, and limited opportunities to stop for in-race nutrition. PURPOSE: To date, gravel racing has not been scientifically examined to determine the demands of the sport. Data from cycling road races indicate substantial fluid loss, which may impair exercise performance. This study assessed hydration responses to gravel races of three different distances. METHODS: This field study collected data on saliva osmolarity, body mass, fluid intake, and nutrition knowledge. Variables were assessed before and after a gravel cycling race in April 2023. A total of 121 participants completed pre-race surveys, 53 provided pre-race measures of body mass and saliva osmolarity (SOsm), and 38 participants completed post-race testing. RESULTS: Based on manufacturer cutpoints for SOsm, only 22.6% (n = 12) of participants were hydrated before the race, with 56.6% mildly dehydrated (n = 30), 18.9% moderately dehydrated (n = 10), and 1.9% severely dehydrated (n = 1). Post-race, 15% (n=6) were still hydrated, 20% (n = 8) were mildly dehydrated, 47.5% (n = 19) were moderately dehydrated, and 17.5% (n = 7) were severely dehydrated. Analyses revealed significant decreases in body mass and increases in SOsm from pre- to post-exercise in the two longer race distances (p \u3c 0.05). There was a significant effect of race distance on energy, fluid, carbohydrate, and sodium intake (p \u3c 0.05), but post-hoc comparisons were only significant for fluid intake. Sweat rates were not different (p \u3e 0.05). Change in percent body mass and change in SOsm were not correlated (r = -0.254, p = 0.118). Longer race distances were associated with higher energy, fluid, carbohydrate, and sodium intake. CONCLUSION: This study provides data quantifying the fluid and nutrient intake during mass participation gravel cycling. Future studies should expand on our results by capturing in-race nutrient data and more sensitive hydration assessments

Research on mixture motion and combustion chamber of internal combustion engine

This review paper focuses on the mixture motion into combustion chamber of internal combustion engine. The shape and orientation of the intake port is an important aspect as it defines how the air or fuel/air is delivered to the cylinder and therefore the motion of the fuel/air in the cylinder. Fluid motion into and within the cylinder is known as charge motion and is important due to the influencing turbulence in the cylinder which generally results in faster combustion, which increases combustion efficiency, reduces fuel consumption, reduces knock and pre-ignition in spark ignition engines. The velocity at which the charge enters the cylinder, directing fuel/air towards the spark plug or fuel injector for ignition, the transfer of heat which influences evaporation of the fuel, improving mixing of the fuel/air mixture, and can increase volumetric efficiency, although at the expense of turbulence A main combustion chamber that permits efficient combustion throughout the entire rotational speed range comprising a straight groove extending diametrically from an edge portion of the top surface of a piston and a pair of grooves branching right and left from the straight groove in such a curved manner as to return toward the edge of the surface

Late Miocene wood recovered in Bengal–Nicobar submarine fan sediments by IODP Expedition 362

Drilling and coring during IODP Expedition 362 in the eastern Indian Ocean encountered probably the largest wood fragment ever recovered in scientific ocean drilling. The wood is Late Miocene in age and buried beneath ∼800 m of siliciclastic mud and sand of the Bengal–Nicobar Fan. The wood is well preserved. Possible origins include the hinterland to the north, with sediment transported as part of the submarine fan sedimentary processes, or the Sunda subduction zone to the east, potentially as a megathrust tsunami deposit

The Waiting And Mating Game: Condition Dependent Mate Sampling In Female Gray Treefrogs (Hyla Versicolor)

Strong sexual selection by receivers can lead to the evolution of elaborate courtship behaviors in signalers. However the process by which receivers sample signalers and execute mate choice under complex signaling conditions—and thus the realized strength of sexual section—is poorly understood. Moreover, receivers can vary in condition, which can further influence mate sampling strategies. Using wild female frogs we tested two hypotheses at the intersection of these important problems: that some of the individual variation in mate sampling is explained by (1) the reproductive urgency hypothesis, which predicts that receivers in a more urgent reproductive state will sample mates less and/or (2) the reproductive investment hypothesis, which predicts that receivers that have invested less in the current reproductive effort will sample mates less. Eastern gray treefrogs, Hyla versicolor, were collected in amplexus and repeatedly tested for phonotaxis behavior using a dynamic playback assay. To evaluate if hormonal mechanisms explained variation in the mate sampling, three steroid hormones, estradiol, progesterone, and corticosterone, were collected using a noninvasive water-borne hormone assay, validated for this species in the present study. Finally, we measured clutch size (investment) and the duration of time required for each female to oviposit after being reunited with their male mate (urgency). We found repeatability in many of the behaviors, including mate sampling. We found that females with higher concentrations estradiol and corticosterone made quicker choices, and that females with higher progesterone sampled mates more. We also found that female frogs in a more urgent reproductive state had lower concentrations of progesterone and estradiol, thereby providing the first evidence of a relationship between gonadal hormones and reproductive urgency. Collectively we found some support for the reproductive urgency but not the investment hypothesis. Thus, even though a female frog\u27s reproductive readiness is a highly transient life history stage, fine scale variation in her reproductive timeline could mitigate the strength of directional selection

Solar Proton Transport within an ICRU Sphere Surrounded by a Complex Shield: Combinatorial Geometry

Citation: Wilson JW, Slaba TC, Badavi FF, Reddell BD, and Bahadori AA 2015 Solar Proton Transport within an ICRU Sphere Surrounded by a Complex Shield: Combinatorial Geometry NASA/TP-2015-218980 NASA Langley Research Center: Hampton, VA http://ntrs.nasa.gov/search.jsp?R=20160001628The 3DHZETRN code, with improved neutron and light ion (Z (is) less than 2) transport procedures, was recently developed and compared to Monte Carlo (MC) simulations using simplified spherical geometries. It was shown that 3DHZETRN agrees with the MC codes to the extent they agree with each other. In the present report, the 3DHZETRN code is extended to enable analysis in general combinatorial geometry. A more complex shielding structure with internal parts surrounding a tissue sphere is considered and compared against MC simulations. It is shown that even in the more complex geometry, 3DHZETRN agrees well with the MC codes and maintains a high degree of computational efficiency

Solar Proton Transport Within an ICRU Sphere Surrounded by a Complex Shield: Ray-trace Geometry

Citation: Slaba TC, Wilson JW, Badavi FF, Reddell BD, and Bahadori AA 2015 Solar Proton Transport within an ICRU Sphere Surrounded by a Complex Shield: Ray-Trace Geometry NASA/TP-2015-218994 NASA Langley Research Center: Hampton, VA http://ntrs.nasa.gov/search.jsp?R=20160002213The computationally efficient HZETRN code has been used in recent trade studies for lunar and Martian exploration and is currently being used in the engineering development of the next generation of space vehicles, habitats, and extra vehicular activity equipment. A new version (3DHZETRN) capable of transporting High charge (Z) and Energy (HZE) and light ions (including neutrons) under space-like boundary conditions with enhanced neutron and light ion propagation is under development. In the present report, new algorithms for light ion and neutron propagation with well-defined convergence criteria in 3D objects is developed and tested against Monte Carlo simulations to verify the solution methodology. The code will be available through the software system, OLTARIS, for shield design and validation and provides a basis for personal computer software capable of space shield analysis and optimization