27 research outputs found

    Time domains of the hypoxic ventilatory response in ectothermic vertebrates

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    Over a decade has passed since Powell et al. (Respir Physiol 112:123–134, 1998) described and defined the time domains of the hypoxic ventilatory response (HVR) in adult mammals. These time domains, however, have yet to receive much attention in other vertebrate groups. The initial, acute HVR of fish, amphibians and reptiles serves to minimize the imbalance between oxygen supply and demand. If the hypoxia is sustained, a suite of secondary adjustments occur giving rise to a more long-term balance (acclimatization) that allows the behaviors of normal life. These secondary responses can change over time as a function of the nature of the stimulus (the pattern and intensity of the hypoxic exposure). To add to the complexity of this process, hypoxia can also lead to metabolic suppression (the hypoxic metabolic response) and the magnitude of this is also time dependent. Unlike the original review of Powell et al. (Respir Physiol 112:123–134, 1998) that only considered the HVR in adult animals, we also consider relevant developmental time points where information is available. Finally, in amphibians and reptiles with incompletely divided hearts the magnitude of the ventilatory response will be modulated by hypoxia-induced changes in intra-cardiac shunting that also improve the match between O2 supply and demand, and these too change in a time-dependent fashion. While the current literature on this topic is reviewed here, it is noted that this area has received little attention. We attempt to redefine time domains in a more ‘holistic’ fashion that better accommodates research on ectotherms. If we are to distinguish between the genetic, developmental and environmental influences underlying the various ventilatory responses to hypoxia, however, we must design future experiments with time domains in mind

    The insect pathogenic bacterium Xenorhabdus innexi has attenuated virulence in multiple insect model hosts yet encodes a potent mosquitocidal toxin

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    Today God is first : 365 Meditations on the principles of Christ in the workplace

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    Somehow, keeping Jesus as the first priority in our day is the last thing we make time to manage well! That's why I have loved being on the receiving end of the marketplace meditaions included in TGIF ( To Day god Is First), I was introduced to them thrugh the internet and recommend that this harad copy format be augmented by the "cyber surece" nuggets Os Hillman provids. The fresh spiritual reminfders that come like clockwork through daily e-mails have been a great boost to my starting the day faithfully by putting Jesus Fisrt. Once you get "linked" to the life lessons found in TGIF, this resurce will bae the last thing you will want to drop from an overcrowded schedule!xiv + 396 pages 16 x 23 c
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