7 resultados para classical conditioning, mere exposure effect, classical conditioning of preferences.
em Aquatic Commons
Resumo:
This brief report concentrates on the effect of low pH on the initial stages of decomposition and the conditioning of incoming particulate carbon or detritus by microbes, particularly certain genera of filamentous bacteria. Although many previous reports have concentrated on bacterial decomposition processes, little attention has been given to the composition of the bacterial community and the role of its component parts, particularly in nutrient-poor waters which are provided with sources of organic carbon and reducing power in the form of poor quality detritus.
Resumo:
For monitoring of the engine power of fishing vessels permitted for fishery in the plaice box with engine power of 300 HP or less at sea three different portable power measurement systems are developed and tested. A system measuring the twist of the propeller shaft by two divisible gearwheels mounted on the shaft worked well at shafts with roller bearing at both sides of the measured interval of 100–300 mm length. Only at a very few fishing vessels this system is applicable and therefore for monitoring purposes not suitable. The application of a commercial available system measuring the stress at the surface of the shaft was simplified for application by non experts. The torque is measured by strain gauges. The calibration of the system, measuring and recording of the power is done by a PC automatically. A small polished facet on the shaft protected against oxidation is needed for easy and quick application. In this case the system can be used by technical personnel of supervision boats for monitoring of the engine power at sea in a short time. A third power measurement system determinates the torque by measuring the displacement of two supports clamped on the shaft at a distance of 100 mm. The displacement is measured by a micrometer gauge mounted on one of the supports. Readout of the rotating gauge display is possible taking advantage of stroboscopic effect. The system needs no conditioning of the shaft and can be used by non technicians. The development is not finished until now and some additional investigations and tests are required. Additional measures for monitoring of the power on fishing vessels by self recording power measurement systems and sealed fuel racks with limited injection are reported and discussed.
Resumo:
Hurricanes can cause extensive damage to the coastline and coastal communities due to wind-generated waves and storm surge. While extensive modeling efforts have been conducted regarding storm surge, there is far less information about the effects of waves on these communities and ecosystems as storms make landfall. This report describes a preliminary use of NCCOS’ WEMo (Wave Exposure Model; Fonseca and Malhotra 2010) to compute the wind wave exposure within an area of approximately 25 miles radius from Beaufort, North Carolina for estuarine waters encompassing Bogue Sound, Back Sound and Core Sound during three hurricane landfall scenarios. The wind wave heights and energy of a site was a computation based on wind speed, direction, fetch and local bathymetry. We used our local area (Beaufort, North Carolina) as a test bed for this product because it is frequently impacted by hurricanes and we had confidence in the bathymetry data. Our test bed conditions were based on two recent Hurricanes that strongly affected this area. First, we used hurricane Isabel which made landfall near Beaufort in September 2003. Two hurricane simulations were run first by passing hurricane Isabel along its actual path (east of Beaufort) and second by passing the same storm to the west of Beaufort to show the potential effect of the reversed wind field. We then simulated impacts by a hurricane (Ophelia) with a different landfall track, which occurred in September of 2005. The simulations produced a geographic description of wave heights revealing the changing wind and wave exposure of the region as a consequence of landfall location and storm intensity. This highly conservative simulation (water levels were that of low tide) revealed that many inhabited and developed shorelines would receive wind waves for prolonged periods of time at heights far above that found during even the top few percent of non-hurricane events. The simulations also provided a sense for how rapidly conditions could transition from moderate to highly threatening; wave heights were shown to far exceed normal conditions often long before the main body of the storm arrived and importantly, at many locations that could impede and endanger late-fleeing vessels seeking safe harbor. When joined with other factors, such as storm surge and event duration, we anticipate that the WEMo forecasting tool will have significant use by local emergency agencies and the public to anticipate the relative exposure of their property arising as a function of storm location and may also be used by resource managers to examine the effects of storms in a quantitative fashion on local living marine resources.
Resumo:
EXTRACT (SEE PDF FOR FULL ABSTRACT): Time scales extracted from high-resolution proxy records and observations indicate that the spectrum of climate variability exhibits significant power in the range of decades to centuries superimposed on a red-noise continuum. The classical view of climate variability is based on the concept that observed fluctuations have their origin in periodic forcings on the same time scale. ... Instead, it is proposed that these fluctuations are linked to interactions within and between the different climate system components.
Resumo:
Liza parsia were exposed to sublethal (0.02 ppm) concentration of DDT for 15 days. The gill responded initially with copious secretion of mucus, oedematous separation of epithelial cells from the basement membrane and fusion of secondary gill lamellae. Hyperplasia of the cells lining primary gill lamellae and lamellar telangiectases (or aneurysms) was frequently seen after day 10 of exposure. Kidney exhibited hypertrophy of the epithelial cells lining proximal convoluted tubules which was followed by shrinkage in glomerular tufts, increase in Bowman's space, appearance of amorphous eosinophilic materials in the lumina of the tubules and focal necrosis on day 10 of the treatment. Hyaline droplets and casts were also encountered in the epithelial cells and lumina of the proximal tubules. Liver revealed an initial dilation of canaliculi and increased secretion of bile. Thereafter, the displacement of nuclei towards periphery of the hepatocytes, disorganization of blood sinusoids, pyknotic changes in nuclei, cytolysis and vacuolation as well as focal necrosis were noticed after day 10 of the intoxication.
Resumo:
The sublethal exposure (0.24 ppm) of Nuvan on some biochemical compositions such as serum protein, blood glucose, glutamate oxaloacetate transaminase (AST) and glutamate pyruvate transaminase (ALT) and on some hematological parameters such as red blood corpuscles (RBC), white blood corpuscles (WBC), hemoglobin content (Hb), mean corpuscular concentration (MCV), mean corpuscular hemoglobin concentration (MCHC) of Catla catla fingerlings were studied. The hematological and biochemical parameters evoked a significant reduction (excepting MCV, ALT and AST which is significantly increased) with increasing days of Nuvan exposure.