Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “TIDES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3Linked to original sources

The rising tide of end-stage renal disease: what can be done?

The prevalence of end-stage renal disease (ESRD) is rising throughout the developed and developing world, although the rate of increase may be attenuating in some regions. Type 2 diabetes mellitus, often a consequence of obesity and accompanied by the metabolic syndrome, is a major cause of progressive renal disease and the increasing global burden of ESRD. Strategies that are cost-effective and applicable at the community level are urgently needed to stem the tide of both type 2 diabetes and the resulting ESRD. Primary and secondary prevention measures, involving screening and interventions, have demonstrated beneficial effects when appropriately designed and targeted to "high-risk" groups. If these strategies can be implemented at the societal level and compliance with the interventions is robust, it is entirely possible that the rising tide of ESRD can be converted into a receding tide of ESRD in the future.

Diabetes Mellitus, Type 2↗

Hydroxyl radical generation by red tide algae.

The unicellular marine phytoplankton Chattonella marina is known to have toxic effects against various living marine organisms, especially fishes. However, details of the mechanism of the toxicity of this plankton remain obscure. Here we demonstrate the generation of superoxide and hydroxyl radicals from a red tide unicellular organism, C. marina, by using ESR spectroscopy with the spin traps 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) and N-t-butyl-alpha-phenylnitrone (PBN), and by using the luminol-enhanced chemiluminescence response. The spin-trapping assay revealed productions of spin adduct of superoxide anion (O2-) (DMPO-OOH) and that of hydroxyl radical (.OH) (DMPO-OH) in the algal suspension, which was not observed in the ultrasonic-ruptured suspension. The addition of superoxide dismutase (500 U/ml) almost completely inhibited the formation of both DMPO-OOH and DMPO-OH, and carbon-centered radicals were generated with the disappearance of DMPO-OH after addition of 5% dimethyl sulfoxide (Me2SO) and 5% ethanol. Furthermore, the generation of methyl and methoxyl radicals, which are thought to be produced by the reaction of hydroxyl radical and Me2SO under aerobic condition, was identified using spin trapping with a combination of PBN and Me2SO. Luminol-enhanced chemiluminescence assay also supported the above observations. These results clearly indicate that C. marina generates and releases the superoxide radical followed by the production of hydroxyl radical to the surrounding environment. The velocity of superoxide generation by C. marina was about 100 times faster than that by mammalian phagocytes per cell basis. The generation of oxygen radical is suggested to be a pathogenic principle in the toxication of red tide to susceptible aquaculture fishes and may be directly correlated with the coastal pollution by red tide.

Cyclic N-Oxides↗

Burrow plugging in the crab Uca uruguayensis and its synchronization with photoperiod and tides.

Field observations and laboratory experiments were performed to analyze the burrow plugging behavior of U. uruguayensis and to analyze its relation to two environmental cycles: light-dark cycle and tides. Field observations showed that burrow plugging is a rhythmic behavior synchronized with both environmental cycles such that burrows are open during those periods of simultaneous light and low tide. Laboratory experiments suggested that the plugging rhythm is under endogenous circadian control, whereas its synchronization with the tidal cycle, particularly with periodic inundation, seems to be strongly exogenous, not showing clear circatidal components. It is proposed that burrow plugging is adaptive because it allows the animals to be within an air medium, more suitable for their respiration modality, during high tide and because it prevents burrow collapse. It is also proposed that both the endogenous circadian component and the lack of an endogenous circatidal component can also be explained on the basis of adaptive value, taking into account the regular temporal structure of the solar day and the irregular temporal structure of the tidal cycle.

Animals↗

Gravitational effects of the period of high tides and the new moon on lunacy.

In this report, the established timing of terrestrial tidal gravity fluxes is examined to assess the role of the full moon per se in modern gravitational lunacy theory. The results show that the principal tidal gravity fluxes are semidiurnal, with lesser diurnal and even smaller fortnightly components. There are no uniquely monthly components that would correspond to the period of the full moon. This means that the gravitational effects of the new moon are equivalent to those of the full moon. Furthermore, the gravitational effects associated with the times of high tide are even greater than those associated with the moon phases. Using the technique of reductio ad absurdum, I suggest that lunacy effects, if indeed there are any, should occur twice each day (high tides) but should be more pronounced during the new moon and full moon (spring tides). On the basis of this analysis, I would recommend that all studies that have compared hospital records with the full moon be redone to coincide with the proper timing as found in this report.

Atmospheric Pressure↗

Concentration and particle size of airborne toxic algae (brevetoxin) derived from ocean red tide events.

Red tides in the Gulf of Mexico are formed by blooms of the dinoflagellate Karenia brevis, which produces brevetoxins (PbTx). Brevetoxins can be transferred from water to air in the wind-powered whitecapped waves during red tide episodes. Inhalation exposure to marine aerosol containing PbTx causes respiratory problems. A liquid chromatograph/ tandem mass spectrometric method was developed for the detection and quantitation of several PbTxs in ambient samples collected during red tide events. This method was complemented by a previously developed antibody assay that analyzes the entire class of PbTx compounds. The method showed good linearity, accuracy, and reproducibility, allowing quantitation of PbTx compounds in the 10 pg/m3 range. Air concentrations of PbTxs and brevenal for individual samples ranged from 0.01 to 80 ng/m3. The particle size showed a single mode with a mass median diameter between 6 and 10 microm, which was consistent for all of the PbTx species that were measured. Our results imply that individual PbTxs were from the same marine aerosol or from marine aerosol that was produced from the same process. The particle size indicated the likelihood of high deposition efficiency in the respiratory tract with the majority of aerosol deposited in the upper airways and small but not insignificant deposition in the lower airways.

Aerosols↗

@-tides as reporters for molecular associations.

The 1,6-dihydro-3(2H)-pyridinone unit is an amino acid surrogate that favors the extended beta-strand conformation when incorporated in an oligopeptide ("@-tide") strand. We now report that the circular dichroism (CD) signature of the vinylogous amide in the @-unit is sensitive to conformation in organic and aqueous solvents and, therefore, is useful as a quantitative measure of @-tide association and folding processes that involve this moiety. Moreover, this method can be employed in the micromolar concentration range, which is not readily accessible using other techniques. Measurements of @-tide dimerization and beta-hairpin folding equilibria not only demonstrate the utility and generality of this approach but also provide a way to quantify amino acid side chain-side chain interactions relevant to beta-sheet stability.

Circular Dichroism↗

The magnetic field induced by the bodily tide in the core of the Earth.

The motion in the liquid core of the earth due to the bodily tide can induce a periodic magnetic field having the frequency sigma of the tide as well as multiple frequencies, including a steady term. The coupling coefficient for the steady term between the convectively inducing and induced fields is estimated to be of the order of sigmaH(2)/lambda, where H denotes the height of the equilibrium tide, and lambda = 1/4pikappa, kappa denoting the electrical conductivity of the core. With sigma = 1.4 x 10(-4) sec(-1), H = 20 cm, and kappa = 3 x 10(-6) emu, the coupling coefficient comes out only of the order of 10(-6), as against unity in the case of the dynamo theory.

Journal Article↗

Possible forcing of global temperature by the oceanic tides.

An approximately decadal periodicity in surface air temperature is discernable in global observations from A.D. 1855 to 1900 and since A.D. 1945, but with a periodicity of only about 6 years during the intervening period. Changes in solar irradiance related to the sunspot cycle have been proposed to account for the former, but cannot account for the latter. To explain both by a single mechanism, we propose that extreme oceanic tides may produce changes in sea surface temperature at repeat periods, which alternate between approximately one-third and one-half of the lunar nodal cycle of 18.6 years. These alternations, recurring at nearly 90-year intervals, reflect varying slight degrees of misalignment and departures from the closest approach of the Earth with the Moon and Sun at times of extreme tide raising forces. Strong forcing, consistent with observed temperature periodicities, occurred at 9-year intervals close to perihelion (solar perigee) for several decades centered on A.D. 1881 and 1974, but at 6-year intervals for several decades centered on A.D. 1923. As a physical explanation for tidal forcing of temperature we propose that the dissipation of extreme tides increases vertical mixing of sea water, thereby causing episodic cooling near the sea surface. If this mechanism correctly explains near-decadal temperature periodicities, it may also apply to variability in temperature and climate on other times-scales, even millennial and longer.

Journal Article↗

The shaping of continental slopes by internal tides.

The angles of energy propagation of semidiurnal internal tides may determine the average gradient of continental slopes in ocean basins (approximately 2 to 4 degrees). Intensification of near-bottom water velocities and bottom shear stresses caused by reflection of semi-diurnal internal tides affects sedimentation patterns and bottom gradients, as indicated by recent studies of continental slopes off northern California and New Jersey. Estimates of bottom shear velocities caused by semi-diurnal internal tides are high enough to inhibit deposition of fine-grained sediment onto the slopes.

Journal Article↗

From tides to mixing along the Hawaiian ridge.

The cascade from tides to turbulence has been hypothesized to serve as a major energy pathway for ocean mixing. We investigated this cascade along the Hawaiian Ridge using observations and numerical models. A divergence of internal tidal energy flux observed at the ridge agrees with the predictions of internal tide models. Large internal tidal waves with peak-to-peak amplitudes of up to 300 meters occur on the ridge. Internal-wave energy is enhanced, and turbulent dissipation in the region near the ridge is 10 times larger than open-ocean values. Given these major elements in the tides-to-turbulence cascade, an energy budget approaches closure.

Journal Article↗

Ocean science. Enhanced: internal tides and ocean mixing.

Recent satellite and in situ observations have shown that at ocean ridges and other seafloor topographic features, a substantial amount of energy is transferred from the main ocean tides into "internal tides." In his Perspective, Garrett explains how these internal waves with tidal periods propagate through the density-stratified deep ocean and eventually break down into turbulence. The resulting mixing affects ocean stratification and ocean circulation. It thus influences climate as well as biological production. The energy for the internal tides is derived from the rotational energy of the Earth-Moon system changes of the length of the day and the distance to the Moon.

Journal Article↗

Weather variability, tides, and Barmah Forest virus disease in the Gladstone region, Australia.

In this study we examined the impact of weather variability and tides on the transmission of Barmah Forest virus (BFV) disease and developed a weather-based forecasting model for BFV disease in the Gladstone region, Australia. We used seasonal autoregressive integrated moving-average (SARIMA) models to determine the contribution of weather variables to BFV transmission after the time-series data of response and explanatory variables were made stationary through seasonal differencing. We obtained data on the monthly counts of BFV cases, weather variables (e.g., mean minimum and maximum temperature, total rainfall, and mean relative humidity), high and low tides, and the population size in the Gladstone region between January 1992 and December 2001 from the Queensland Department of Health, Australian Bureau of Meteorology, Queensland Department of Transport, and Australian Bureau of Statistics, respectively. The SARIMA model shows that the 5-month moving average of minimum temperature (b=0.15, p-value<0.001) was statistically significantly and positively associated with BFV disease, whereas high tide in the current month (b=-1.03, p-value=0.04) was statistically significantly and inversely associated with it. However, no significant association was found for other variables. These results may be applied to forecast the occurrence of BFV disease and to use public health resources in BFV control and prevention.

Alphavirus↗

[Preliminary analysis of the characteristics of red tide areas in Changjiang River estuary and its adjacent sea].

A review was made on the main environmental characteristics such as currents and water body, diluted water and its turning direction, upwelling, front, nutrients and its sources and plankton community in the Changjiang River estuary and its adjacent sea areas which could affect the growth, migration, assembling, resting and competition of harmful algae to form red tides. Analyses were also conducted to reveal features of the red tides events recorded in this area in terms of time, location and causative species. Some preliminary results from recent cruises carried out in the investigated sea area, where red tides were frequently occurring, were introduced.

China↗

[Distributions of COD and petroleum hydrocarbons and their relationships with occurrence of red tide in East China Sea].

Based on the data of COD and petroleum hydrocarbons collected in the cruise from April 25 to May 2, 2002 in intensive red tide occurrence areas in East China Sea, the distribution of COD, and petroleum hydrocarbons and the eutrophication index(EI) were analyzed. The results showed that the EI and COD value were both high in coastal water, and decreased gradually away from shore. After the preliminary study on the relationships between correlative factors and occurrence of red tide, it was found that high EI and COD were necessary. There would be great chances for the red tide to break out under conditions that the EI was between 2.5 and 15 and COD concentration was between 0.8 to 1.4 mg.L-1 in seawater, along with the favorable temperature and salinity.

China↗

Fouling coverage of a green tide alga, Ulva pertusa on some antifouling test surfaces exposed to Ayagin harbor waters, east coast of South Korea.

Toxic antifouling chemicals released into the seawaters leads to marine environmental degradation. In order to identify a nontoxic antifoulant, an assessment of antifouling (AF) efficacy of some AF candidates was made at Ayagin harbor, east coast of South Korea. In this static panel study conducted during October 2000-March 2001, some commercial antifoulants, seaweed and seagrass extracts were screened. On panel surfaces coated with a seaweed extract, Ishige okamurae exhibited effective AF activity. Ulva pertusa was encountered as a 'monospecific' fouler with fairly high fouling coverage on many of the test panel surfaces. In recent years the increased influx of inorganic pollutants in the coastal waters causes exorbitant growth of fouling marine algae found all along the Korean peninsula. Especially, a cosmopolitan ship fouling alga U. pertusa occur with high abundance. It was largely suggested that the proposed international ban on the toxic antifoulant tributyltin (TBT) had significant effect on the 'green tide' phenomenon occurring in different parts of the world. However, it appears that Korean scenario of 'green tide' is a localized. Antifouling efficacy of some AF coatings and fouling coverage of a green tide alga, U. pertusa are discussed.

Animals↗

Biological activity of a red-tide alga--A. tamarense under co-cultured condition with bacteria.

The relationship between Alexandrium tamarense (Lebour) Balech, one of red-tide alga, and two strains of marine bacteria, Bacillius megaterium (S7) and B. halmapulus (S10) isolated from Xiamen Western Sea, was investigated by evaluating the growth state of A. tamarense and the variation of beta-glucosidase activity in co-culture system. The results showed the growth and multiplication of the alga were related with the concentration, genus speciality of the bacteria, and growth stage of the alga itself. The growth of A. tamarense was obviously inhibited by S7 and S10 at high concentration. Either inhibition or promotion contributed much more clearly in earlier than in later stage of the growth of the alga. Furthermore, there was a roughly similar variation trend of the activity of extra-cellular enzyme, beta-glucosidase, in the water of the separately co-cultured bacteria S7 and S10 with the alga. The beta-glucosidase activity (beta-GlcA) rapidly increased during the later algal growth accompanying the increase of the lysis of the alga cells. The obvious inhibition of A. tamarense by marine bacteria at high concentration and evident increase of beta-GlcA in co-colture system would help us in better understanding the relationship between red-tide alga and bacteria, and also enlightenedus the possible use of bacteria in the bio-control of red-tide.

Animals↗

[Semi-analysis algorithm to retrieve pigment concentrations in the red tide area of the East China Sea].

For the purpose of detecting and forecasting research of red tides to reduce the loss, a semi-analytic algorithm to retrieve chlorophyll-a concentrations was established in the area where red tides often brought out, according to the data collected during the red tides cruise in the East China Sea in April 2002. In the algorithm, empirical equations were made based on the coefficients from the in-situ data, including the optical properties of the research area. The in-situ data were used to validate the algorithm. The discrepancy of chlorophyll-a absorption coefficients and concentrations are mainly located in the region of 30%. The root mean deviation of the chlorophyll-a concentrations between the observed and the calculated is 0.24, the maximum relative deviation 40.93%, the mean relative deviation 18.83% and the correlation coefficient 0.83. The results show that the precision of the algorithm is high and the algorithm is fit for the research area.

Algorithms↗

Growth physiology of red-tide microorganisms.

The occurrence of red tides, which often cause mass mortality of marine animals and/or shellfish poisoning in humans, is increasing in the estuaries and coastal zones of the world. Species of dinoflagellates are most commonly responsible, though other flagellates, and even ciliates, can also cause red tides. In recent years, understanding of the growth physiology of red-tide microalgae has grown. Each causative organism has a species-specific preference and requirement for temperature, salinity, pH, the basic nutrients, and growth factors, and the toxin formation is affected by these environmental factors.

Animals↗