104 research outputs found
Exhaustive exercise training enhances aerobic capacity in American alligator (Alligator mississippiensis)
The oxygen transport system in mammals is extensively remodelled in response to repeated bouts of activity, but many reptiles appear to be âmetabolically inflexibleâ in response to exercise training. A recent report showed that estuarine crocodiles (Crocodylus porosus) increase their maximum metabolic rate in response to exhaustive treadmill training, and in the present study, we confirm this response in another crocodilian, American alligator (Alligator mississippiensis). We further specify the nature of the crocodilian training response by analysing effects of training on aerobic [citrate synthase (CS)] and anaerobic [lactate dehydrogenase (LDH)] enzyme activities in selected skeletal muscles, ventricular and skeletal muscle masses and haematocrit. Compared to sedentary control animals, alligators regularly trained for 15Â months on a treadmill (run group) or in a flume (swim group) exhibited peak oxygen consumption rates higher by 27 and 16%, respectively. Run and swim exercise training significantly increased ventricular mass (~11%) and haematocrit (~11%), but not the mass of skeletal muscles. However, exercise training did not alter CS or LDH activities of skeletal muscles. Similar to mammals, alligators respond to exercise training by increasing convective oxygen transport mechanisms, specifically heart size (potentially greater stroke volume) and haematocrit (increased oxygen carrying-capacity of the blood). Unlike mammals, but similar to squamate reptiles, alligators do not also increase citrate synthase activity of the skeletal muscles in response to exercise
Hydrokinetic Turbine Effects on Fish Swimming Behaviour
Hydrokinetic turbines, targeting the kinetic energy of fast-flowing currents, are under development with some turbines
already deployed at ocean sites around the world. It remains virtually unknown as to how these technologies affect
fish, and rotor collisions have been postulated as a major concern. In this study the effects of a vertical axis
hydrokinetic rotor with rotational speeds up to 70 rpm were tested on the swimming patterns of naturally occurring
fish in a subtropical tidal channel. Fish movements were recorded with and without the rotor in place. Results showed
that no fish collided with the rotor and only a few specimens passed through rotor blades. Overall, fish reduced their
movements through the area when the rotor was present. This deterrent effect on fish increased with current speed.
Fish that passed the rotor avoided the near-field, about 0.3 m from the rotor for benthic reef fish. Large predatory fish
were particularly cautious of the rotor and never moved closer than 1.7 m in current speeds above 0.6 ms-1. The
effects of the rotor differed among taxa and feeding guilds and it is suggested that fish boldness and body shape
influenced responses. In conclusion, the tested hydrokinetic turbine rotor proved non-hazardous to fish during the
investigated conditions. However, the results indicate that arrays comprising multiple turbines may restrict fish
movements, particularly for large species, with possible effects on habitat connectivity if migration routes are
exploited. Arrays of the investigated turbine type and comparable systems should therefore be designed with gaps of
several metres width to allow large fish to pass through. In combination with further research the insights from this
study can be used for guiding the design of hydrokinetic turbine arrays where needed, so preventing ecological
impacts
NHR-49 Helps Germline-Less Worms Chew the Fat
In C. elegans, removal of the germline extends lifespan significantly. We demonstrate that the nuclear hormone receptor, NHR-49, enables the response to this physiological change by increasing the expression of genes involved in mitochondrial ÎČ-oxidation and fatty-acid desaturation. The coordinated augmentation of these processes is critical for germline-less animals to maintain their lipid stores and to sustain de novo fat synthesis during adulthood. Following germline ablation, NHR-49 is up-regulated in somatic cells by the conserved longevity determinants DAF-16/FOXO and TCER-1/TCERG1. Accordingly, NHR-49 overexpression in fertile animals extends their lifespan modestly. In fertile adults, nhr-49 expression is DAF-16/FOXO and TCER-1/TCERG1 independent although its depletion causes age-related lipid abnormalities. Our data provide molecular insights into how reproductive stimuli are integrated into global metabolic changes to alter the lifespan of the animal. They suggest that NHR-49 may facilitate the adaptation to loss of reproductive potential through synchronized enhancement of fatty-acid oxidation and desaturation, thus breaking down some fats ordained for reproduction and orchestrating a lipid profile conducive for somatic maintenance and longevity
Fluid Intelligence and Psychosocial Outcome: From Logical Problem Solving to Social Adaptation
While fluid intelligence has proved to be central to executive functioning, logical reasoning and other frontal functions, the role of this ability in psychosocial adaptation has not been well characterized.Lower fluid intelligence scores were associated with physical violence, both in the role of victim and victimizer. Drug intake, especially cannabis, cocaine and inhalants and lower self-esteem were also associated with lower fluid intelligence. Finally, scores on the perceived mental health assessment were better when fluid intelligence scores were higher.Our results show evidence of a strong association between psychosocial adaptation and fluid intelligence, suggesting that the latter is not only central to executive functioning but also forms part of a more general capacity for adaptation to social contexts
Developmental phenotype in Phelan-McDermid (22q13.3 deletion) syndrome: a systematic and prospective study in 34 children
Vampires in the village Ćœrnovo on the island of KorÄula: following an archival document from the 18th century
SrediĆĄnja tema rada usmjerena je na raĆĄÄlambu spisa pohranjenog u DrĆŸavnom arhivu u Mlecima (fond: Capi del Consiglio deâ Dieci: Lettere di Rettori e di altre cariche) koji se odnosi na dogaÄaj iz 1748. godine u korÄulanskom selu Ćœrnovo, kada su mjeĆĄtani â vjerujuÄi da su se pojavili vampiri â oskvrnuli nekoliko mjesnih grobova. U radu se podrobno iznose osnovni podaci iz spisa te reÄeni dogaÄaj analizira u ĆĄirem druĆĄtvenom kontekstu i prate se lokalna vjerovanja.The main interest of this essay is the analysis of the document from the State Archive in Venice (file: Capi del Consiglio deâ Dieci: Lettere di Rettori e di altre cariche) which is connected with the episode from 1748 when the inhabitants of the village Ćœrnove on the island of KorÄula in Croatia opened tombs on the local cemetery in the fear of the vampires treating.
This essay try to show some social circumstances connected with this event as well as a local vernacular tradition concerning superstitions
Example-Based Learning: Integrating Cognitive and Social-Cognitive Research Perspectives
Behavior change interventions and policies influencing primary healthcare professionalsâ practiceâan overview of reviews
- âŠ