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Stemming the tide of acute pulmonary edema.
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Finance ... bad tidings for hospitals in Philadelphia and Pittsburgh.
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The ageing face. Stemming the tide with cosmetic surgery.
Over the past decade there has been growing media focus on cosmetic surgery, with greatly increased public acceptance which has spread through all ethnic groups in our society, especially in second and third generation Australians. The acceptance and desire for male cosmetic surgery is also increasing but not at the level of their female counterparts. Increased requests for cosmetic surgery now cover all socioeconomic groups.
Holiday lectures bring tidings of good science.
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Want to go with the flow? A state-side ride with the tide might spell disaster for your Canadian practice.
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The rising tide of hospitalism: evidence-based or anecdote-based medicine?
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The red tide and other phytoplanktonic thoughts.
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It's time to turn the tide.
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Feeding rhythms of the green-lipped mussel, Perna viridis (Linnaeus, 1758) (Bivalvia: Mytilidae) during spring and neap tidal cycles.
Food availability and feeding responses of the green mussel Perna viridis were investigated for two complete tidal cycles during both spring and neap tides. Temporal changes in total particulate matter (TPM), particulate inorganic matter (PIM) and particulate organic matter (POM), were smaller during neap than spring tides. Seston characteristics at different times of a tidal cycle were compared for both spring and neap tides. Only during spring tides were TPM and PIM significantly higher at high tides while POM remained relatively constant (P>0.05). The clearance rate of the mussels underwent temporal variations with tides, and was a negative power function of TPM and a positive linear function of f (organic content), during both spring and neap tides. f was the key factor influencing filtration rate, organic ingestion rate, absorption rate and absorption efficiency. All feeding rates increased linearly with increases in organic content. Pseudofaeces were produced only during spring but not neap tides. Feeding rates and absorption efficiency were highest at low and lowest at high tides (P<0.01). There was no significant temporal change in the wet weight and protein content of the crystalline style with the tidal regime. For the digestive gland, alpha-amylase activity was higher at spring than at neap tides, and higher during high tides in a tidal cycle. The digestive gland cellulase activity did not change significantly with the tides. For the crystalline style, both the activity of cellulase and alpha-amylase were not significantly different (P>0.05) between spring and neap tides. Tidal rhythms in feeding and digestion in this species were likely controlled by temporal variations in food availability in the seawater. By adjusting feeding rates and enzymatic activities, absorption in Perna viridis remained constant, irrespective of the changes in food availability.
[Zooplankton in north branch waters of Changiiang Estuary].
Based on the investigation data during the high-water (July, 2003) and low-water (January, 2004) periods, a causal analysis was made on the variation of zooplankton distribution in the north branch waters of the Changjiang Estuary. The results showed that in high-water period, the average of zooplankton biomass was 234.38 mg x m(-3), being 141.35 mg x m(-3) in flood tide and 327.40 mg x m(-3) in ebb tide, while in low-water period, it was 188.81 mg x m(-3), being 184.69 mg x m(-3) in flood tide and 192.93 mg x m(-3) in ebb tide. The biomass increased from the east to the west in flood tide, but a contrary trend was observed in ebb tide. The species number did not change obviously both in flood tide and in ebb tide. The value of diversity index (H') was higher in flood tide than in ebb tide. In high-water period, the biomass near the north shore was higher than that near the south shore, but it was contrary in the ebb tide. The difference between the waters of two shores was not obvious in low-water period as in high-water period, though the trend of biomass variation was similar. The variation of zooplankton distribution in the north branch waters of the Changjiang Estuary had a close relation with the seasonal changes of zooplankton biomass outside the Changjiang Estuary and the tide, but not significantly related with the Changjiang runoff water. Coriolis force accounted for the difference of zooplankton biomass in the waters of two shores via tide movement.
Tidal forcing of enterococci at marine recreational beaches at fortnightly and semidiurnal frequencies.
Marine beach water quality is typically monitored in early morning once a week without respect to tidal condition. To assess the effect of tide on this public health warning system, we analyzed enterococci (ENT) data from 60 southern California marine beaches with differing geomorphology, orientation, and proximity to runoff sources. ENT concentrations during spring tides were significantly higher (p < 0.1) than those during neap tides at 50 of the beaches, and at the majority of these, water samples were also more than twice as likely to be out of compliance with the ENT single-sample standard during spring tides compared to neap tides. When tide range (spring/neap) and tide stage (ebb/flood) conditions were considered together, spring-ebb tides yielded the highest ENT concentrations and the greatest chance of exceeding the single-sample standard at the majority of beaches. The proximity to a terrestrial runoff source, the slope of the runoff source, the slope of the beach, and the orientation of the beach had minimal influence on the tidal modulation of ENT concentrations. The presence of spring and spring-ebb tide signals at such a great percentage of beaches suggests that tide should be considered in the design and interpretation of beach monitoring program data. It also suggests that ENT delivered by tidally forced sources other than terrestrial surficial runoff are widespread. Possibilities include ENT-laden groundwater (saline and fresh) from the beach aquifer as well as ENT-enriched sands, decaying wrack, and bird feces near the high water line.
Steady-state kinetic mechanism of PDK1.
PDK1 catalyzes phosphorylation of Thr in the conserved activation loop region of a number of its downstream AGC kinase family members. In addition to the consensus sequence at the site of phosphorylation, a number of PDK1 substrates contain a PIF sequence (PDK1-interacting fragment), which binds and activates the kinase domain of PDK1 (PDK1(deltaPH)). To gain further insight to PIF-dependent catalysis, steady-state kinetic and inhibition studies were performed for His6-PDK1(deltaPH)-catalyzed phosphorylation of PDK1-Tide (Tide), which contains an extended "PIF" sequence C-terminal to the consensus sequence for PDK1 phosphorylation. In two-substrate kinetics, a large degree of negative binding synergism was observed to occur on formation of the active ternary complex (alphaKd(ATP) = 40 microM and alphaKd(Tide) = 80 microM) from individual transitory binary complexes (Kd(ATP) = 0.6 microM and Kd(Tide) = 1 microM). On varying ATP concentrations, the ADP product and the (T/E)-PDK1-Tide product analog (p'Tide) behaved as competitive and noncompetitive inhibitors, respectively; on varying Tide concentrations, ADP and p'Tide behaved as noncompetitive and competitive inhibitors, respectively. Also, negative binding synergism was associated with formation of dead-end inhibited ternary complexes. Time progress curves in pre-steady-state studies under "saturating" or kcat conditions showed (i) no burst or lag phenomena, (ii) no change in reaction velocity when adenosine 5'-O-(thiotriphosphate) was used as a phosphate donor, and (iii) no change in reaction velocity on increasing relative microviscosity (0 < or = eta/eta0 < or = 3). Taken together, PDK1-catalyzed trans-phosphorylation of PDK1-Tide approximates a Rapid Equilibrium Random Bi Bi system, where motions in the central ternary complex are largely rate-determining.
Is there an endogenous tidal foraging rhythm in marine iguanas?
As strictly herbivorous reptiles, Galápagos marine iguanas graze on algae in the intertidal areas during low tide. Daily foraging rhythms were observed on two islands during 3 years to determine the proximate factors underlying behavioral synchrony with the tides. Marine iguanas walked to their intertidal foraging grounds from far-off resting areas in anticipation of the time of low tide. Foraging activity was restricted to daytime, resulting in a complex bitidal rhythm including conspicuous switches from afternoon foraging to foraging during the subsequent morning when low tide occurred after dusk. The animals anticipated the daily low tide by a maximum of 4 h. The degree of anticipation depended on environmental parameters such as wave action and food supply. "Early foragers" survived in greater numbers than did animals arriving later at foraging sites, a result indicating selection pressure on the timing of anticipation. The timing of foraging trips was better predicted by the daily changes in tabulated low tide than it was by the daily changes in actual exposure of the intertidal foraging flats, suggesting an endogenous nature of the foraging rhythms. Endogenous rhythmicity would also explain why iguanas that had spontaneously fasted for several days nevertheless went foraging at the "right" time of day. A potential lunar component of the foraging rhythmicity of marine iguanas showed up in their assemblage on intertidal rocks during neap tide nights. This may indicate that iguanas possessed information on the semi-monthly rhythms in tide heights. Enclosure experiments showed that bitidal foraging rhythms of iguanas may free run in the absence of direct cues from the intertidal areas and operate independent of the light:dark cycle and social stimuli. Therefore, the existence of a circatidal oscillator in marine iguanas is proposed. The bitidal foraging pattern may result from an interaction of a circadian system with a circatidal system. Food intake or related stimuli may be used as tidal zeitgebers in synchronizing the foraging rhythms of these reptiles under natural conditions.
Hatching rhythms of Uca thayeri Rathbun: timing in semidiurnal and mixed tidal regimes.
We compared the timing of larval release by Uca thayeri exposed to different tidal regimes. Crabs on Florida's East Coast experience semidiurnal tides, whereas crabs on the Florida's West Coast experience mixed tides.In both populations, hatching occurred shortly after high tide. On the East Coast, most crabs released their larvae between dusk and midnight, a few days before the maximum amplitude spring tides. On the West Coast, most crabs released their larvae during the afternoon tropic tides of greater amplitude. West Coast crabs may release during the day because ebbing tides at night are too weak for effective transport. Thus, at each location, hatching occurs when phase relationships between the ebbing tides, the light-dark cycle, and tidal amplitude are most favorable. Further study is required to determine whether females on each Coast show fixed responses to each tidal regime, or whether they can alter their hatching rhythms upon exposure to different tides.
Further applications of blood gas analysis to gastric acidity determination.
It has been shown that the transient increase in total body bicarbonate that accompanies any acceleration of gastric acid secretion (the 'alkaline tide') is derivable from the associated changes in base excess in arterial blood and is precisely equivalent to the amount of acid secreted when the latter is simultaneously recovered. For the alkaline tide to qualify as a 'tubeless' measure of acid secretion, its equivalence to the latter has to be demonstrated without simultaneous aspiration of gastric juice. We therefore studied the course of the alkaline tide following pentagastrin injection and its relationship to pentagastrin-stimulated acid secretion as measured by aspiration on a separate occasion. In 12 duodenal ulcer patients, the sequential changes in base excess in arterial blood in response to pentagastrin invariably described coherent curves. Peak values occurred most frequently 45 min after injection. In 12 similar patients, alkaline tide 45 min after pentagastrin, as per analysis of arterialized venous blood, correlated well (r = 0.86) with 'peak acid output' (PAO) as measured by aspiration at another time. In 14 patients post vagotomy and pyloroplasty for duodenal ulcer, the 45-min alkaline tide was determined as above and PAO was predicted from the previously established regression-line: The 3 patients with recurrent duodenal ulceration had the highest predicted values for PAO, clearly discriminating them from the others. Measurement of alkaline tide holds promise as a valuable substitute for conventional gastric analysis. For the sake of accuracy, readings should be based on individually constructed time-curves of base excess, in preference to the raw data. Arterialized venous blood appears to be satisfactory substitute for arterial blood for studies of this type.