Changes in the thermoregulatory mechanisms of juvenile bigeye tuna (Thunnus obesus) as body size increases were investigated by comparing associative (fish associated with floating objects) and ...characteristic (non‐associative) behaviors using archival tag data from 15 fish released in Japanese waters 49–72 cm fork length (FL) at release, 3–503 days. The thermal excess (body temperature minus ambient temperature) during characteristic behavior was about 0.7–2.3°C higher than that during associative behavior in equally sized fish, and both increased with body size. Heat budget models indicated that the increases in the thermal excess of both behaviors could be attributed to decreases in the whole‐body heat transfer coefficient (λ) while descending. Thermoregulatory mechanisms appear to develop with body size by controlling λ during descents and ascents, especially in characteristic behavior (associative: 50 cm FL, 2.6‐fold; 95 cm FL, 6.4‐fold; characteristic: 55 cm FL, 5.5‐fold; 95 cm FL, 15.8‐fold). The λ increases while ascending to allow rapid body temperature recovery by absorbing the ambient heat in warmer, shallower water and is restricted for thermoconservation while descending to deeper, cooler water. The heat production results and calculated body temperatures for both behaviors suggest that associative behavior is the inactive state, so physiological thermoregulatory energy may be less necessary than during characteristic behavior. As body bulk λ decreased with body size, it appears that physiological thermoregulation, by controlling arterial blood flow and/or vasoconstriction, develops to adapt to deeper, offshore waters for better exploitation of prey, in turn supporting the increasing energy demands of larger fish.
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DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
The fundamental principles of the vibration theory as a classical science are widely used for the description of movements of technical objects and mechanical systems. Vibrations of real objects are ...complicated by non-linear characteristics of stiffness of the medium to be compacted and viscous friction forces. Usable vertical movements of a vibratory drum have been determined whereby the technological compaction operation of materials and soils is performed. The methods of the vibratory drum vertical movement determination have been developed by means of considering the vibratory drum downward movement during the semi-period of one rotation of the eccentric weight. The operating process of the road roller vibratory drum is composed of sequential periodic transient operating processes of the material compaction and idle cycles in each turn of the eccentric weight rotation. Within the process of the study the operating process is considered of the vibratory drum downward movement during the material compaction, consisting of free damped and undamped forced downward movements of the vibratory drum. For the first time the damping time of transient processes during the analysis of forced oscillatory processes is regulated by the semi-period time of the eccentric weight rotation t = 0.5T.
Long-term 2D simulation of rainwater infiltration into road embankments built on expansive soils is lacking in most highway design strategies. This paper explores the application of Hydrus-2D to ...establish a finite element model capable of performing long-term simulations of water flow in road embankments subjected to seasonal rainfall. Toward that end, climate specific suction profiles are generated from the simulations using real time climate data, which are used to predict vertical movement at the pavement edge. Sensitivity analyses show that the initial moisture condition has the most significant effect on moisture distribution and suction profile patterns. This induces a maximum decrease in vertical movement of 3.0 cm when a dry initial moisture state is compared with a wet initial moisture state. Higher values of evaporation rate and hydraulic conductivity result in less long-term vertical movement, although the impact is less obvious compared to initial moisture condition. The results also indicate that an extreme rain event can double the vertical displacement of pavements when compared to normal rain events, which proves the importance of using real climate data when expansive soils are involved. A case study presented the advantages of using Hydrus-2D suction profiles to predict vertical movement of pavements.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Vertical movements related to the thermoregulation were investigated in 12 juvenile bigeye tuna (Thunnus obesus) in Japanese waters using archival tag data. Movements changed with time of day, ...season, and body size. During daytime, bigeye tuna descended to greater depths, presumably to feed in the deep scattering layer (DSL). Thereafter, they repeatedly ascended to shallower layers, suggesting attempts at behavioral thermoregulation, although the beginning of vertical thermoregulatory ascents might reflect a shift in DSL depth. By the end of such movement, the whole‐body heat‐transfer coefficient might decrease because, although the depth and ambient temperature of the upper layers did not change, the body temperature gradually decreased significantly just after ascent for thermoregulation. Seasonal patterns indicated that the vertical thermal structure of the ocean might influence this ascent behavior. For example, from January to May, bigeye tuna made fewer ascents to less shallow waters, suggesting that they respond to increasing depths of the mixed surface layer by reducing energy expenditure during vertical migration. In addition, as body size increased, fewer thermoregulatory ascents were required to maintain body temperature, and fish remained deeper for longer periods. Thus, vertical thermoregulatory movements might change with body size as bigeye tuna develop better endothermic and thermoregulatory abilities. We hypothesize that bigeye might also increase cold tolerance as they grow, possibly due to ontogenetic shifts in cardiac function.
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DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
Tiger sharks,
, are a keystone, top-order predator that are assumed to engage in cost-efficient movement and foraging patterns. To investigate the extent to which oscillatory diving by tiger sharks ...conform to these patterns, we used a biologging approach to model their cost of transport. High-resolution biologging tags with tri-axial sensors were deployed on 21 tiger sharks at Ningaloo Reef for durations of 5-48 h. Using overall dynamic body acceleration as a proxy for energy expenditure, we modelled the cost of transport of oscillatory movements of varying geometries in both horizontal and vertical planes for tiger sharks. The cost of horizontal transport was minimized by descending at the smallest possible angle and ascending at an angle of 5-14°, meaning that vertical oscillations conserved energy compared to swimming at a level depth. The reduction of vertical travel costs occurred at steeper angles. The absolute dive angles of tiger sharks increased between inshore and offshore zones, presumably to reduce the cost of transport while continuously hunting for prey in both benthic and surface habitats. Oscillatory movements of tiger sharks conform to strategies of cost-efficient foraging, and shallow inshore habitats appear to be an important habitat for both hunting prey and conserving energy while travelling.
Knowledge of patterns and drivers of the spatiotemporal distribution of top predatory fish is key to understand ecological dynamics and to successful management. Here, we integrated field and ...laboratory approaches to study vertical movements of pike (Esox lucius) in relation to season, light regimes and body temperature. We tagged pike from the Baltic Sea with data storage tags during spawning migration and retrieved them during migration the following years to obtain high‐resolution data from full year of movements. The results showed seasonal and diel patterns of activity and body temperature that conformed to distinct patterns of crepuscular activity and diel vertical migrations. The latter manifested as two different patterns, either a stationary phase in the surface water during day followed by night‐time in deeper water or vice versa. The occurrence of these two behaviours varied among individuals and within individuals among seasons. Diel vertical migration has previously not been described for this shallow‐dwelling species, but was a common and consistent behaviour among individuals in this study. We suggest that the function of the daytime surface behaviour in pike is to increase body temperature through sun basking. This thermoregulatory role of surfacing was supported by the laboratory study where individuals sought the surface layer, exposed themselves to infrared light and thereby attained body temperatures in excess of ambient water. These results support sun basking as a mechanism for heat gain and further suggest that access to sunlight in the surface layer could be an important driver of vertical migrations.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
This study examined individual ascent and descent performance on long straight stairs. A field experiment was conducted in a subway station in China involving 30 healthy volunteers with mean (SD) age ...of 38.6 (16.1). Each participant was required to ascend 71.4 m height straight stairs consisted of 6 stair sections, then required to descend the same stairs after an enough rest period. During the rest period, the participant was asked to answer a questionnaire related to individual subjective estimation of upward movement. Movement parameters including overall speed, local speed and individual cadences as well as physiological indicators like blood pressure (BP) and heart rate (HR) were recorded and discussed. The mean individual upward overall speed is 0.81 m/s, while the mean individual downward overall speed is 1.03 m/s. The local speed exhibited a progressive reduced tendency within each stair section reflecting the development of leg muscle fatigue, and then presented a higher value when the subjects passed through the transition passageway and entered a new stair section meaning a small recovery during walking on horizontal passageway. With respective to the BP results, only systolic blood pressure appeared a significant increment after the experiment in the case of upward movement, except for the young female group, indicating that stair-ascending evacuation was vigorous exercise. The results of HR experienced a sharp increase within the first 10 s followed gradual increase, and then maintained constant. The questionnaire results showed that, there was a high percentage of participants (about 50%) used the handrail but with a relatively low individual usage frequency (13.4%) during stair-ascending. Some participants (about 10%) started to feel very tired when finished the movement of three stair sections (about 33.9 m height), and almost 40% participants felt very tired when finished the whole upward evacuation (71.4 m height).
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CEKLJ, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Muito embora o GPS (Sistema Global de Posicionamento) tenha sido primeiramente construído para o posicionamento geodésico e a navegação, o sistema possibilitou analisar diversos fenômenos terrestres, ...de forma que novas aplicações vêm surgindo nos últimos anos. No sentido de ampliar as aplicações do posicionamento geodésico, este trabalho investiga as possíveis relações entre as variações do nível de um rio em comparação com as altitudes estimadas a partir de soluções geodésicas, notadamente associadas a uma estação de monitoramento contínuo do GPS. As soluções geodésicas precisas do SIRGAS (Sistema de Referência Geocêntrico para as Américas) foram confrontadas com as observações hidrológicas realizadas pela ANA (Agência Nacional de Águas). Duas estações foram selecionadas e são localizadas em uma região com grande extensão de área alagável, o complexo do Pantanal. Os resultados apresentaram que há uma forte anti-correlação entre o aumento do nível de água com a redução da altitude geodésica, mostrando que o posicionamento geodésico pode auxiliar no monitoramento das variações do nível de um rio.
The activity patterns for most animals are determined through a trade-off among competing processes, such as foraging behaviour, predator or competitor avoidance, and maintaining bioenergetic ...efficiency. We used active and passive acoustic telemetry to examine what processes may contribute to diel and seasonal patterns of vertical movement in 27 sixgill sharks in Puget Sound, WA, U.S.A., from December 2005 to December 2007. We found clear and consistent patterns of diel activity; sixgill sharks were typically shallower and more active at night than during the day. In Elliott Bay, WA, sixgill sharks made direct vertical movements at sunrise and sunset, while vertical movements were more variable in deeper, main channel waters. The greatest rates of ascent and descent in sixgill sharks occurred most often during night-time ebb tides. Seasonally, sixgill sharks occupied deeper habitats during the autumn and winter than during spring and were most active in the autumn. We also found synchronous vertical movements in three of four shark pairs tracked simultaneously, evidence that these sharks were responding to similar stimuli. Clear and consistent patterns of diel activity throughout the year across size and sex of sharks and across multiple spatial scales is most consistent with the hypothesis that foraging behaviour is responsible for the patterns of diel vertical movement of sixgill sharks in Puget Sound.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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