http://ieeexplore.ieee.org/iel5/5/31047/01444179.pdf

Fundamentals of acoustics

The yield of alkenols and cycloalkenols is substantially improved by carrying out the reaction of olefins with formaldehyde in the presence of selected catalysts. In accordance with one embodiment, alk-3-en-1-ols are produced in good yields from isobutylene and formaldehyde in the presence of organic carboxylic acid salts of Group IB metals.

The Organization of the Cochlear Receptor

The Communication program emphasizes theory, research, and application to examine the ways humans communicate, verbally and non-verbally, across a variety of levels and contexts. This is particularly important as communication shapes our ideas and values, gives rise to our politics, consumption and socialization, and helps to define our identities and realities. Its power and potential is inestimable. From the briefest of text messages to the grandest of public declarations, we indeed live within communication and invite you to join us in appreciating its increasing importance in contemporary society. From Twitter and reality television to family relationships and workplace dynamics, communication is about understanding ourselves, our media, our relationships, our culture and how these things connect.

의사 간호사 communication

Rates of clearance, ingestion, ammonia excretion, respiration and egg production were measured in food-acclimated (0 to 1700 W C 1-l) planktonic copepods Acartia tonsa in relation to food concentration. Carbon and nitrogen budgets were constructed. Clearance peaked at a food concentration of 150 W C 1-l, and decreased at both higher and lower concentrations. Ingestion and egg production rates increased sigmoidally with food concentration approaching plateaus equivalent to 180 and 64 % body C d-l, respectively. Rates of ammonia excretion and respiration increased with algal concentration in a decelerating manner. Respiration and excretion rates of copepods fed at saturation food concentration were more than 4 times higher than those for starved individuals. The causality of the increased respiration rate in association with feeding (specific dynamic action, SDA) is discussed by considering the physiology and biochemistry of the processes that potentially contribute to SDA. The theoretical biochemical minimum costs of biosynthesis accounted for between 50 and 116 % of observed SDA, while assimilation costs equalled 18 to 28 %. Costs of feeding, digestion and excretion (-1 % of SDA), and the mechanical work required to transport food down the gut, contributed insignificantly to SDA. It is concluded that the increment in metabolic rate of feeding A. tonsa largely relates to biosynthesis ('growth') and transport, and that the efficiency of egg production in this species is near its theoretical maximum.

/pdf/bioenergetics-of-the-planktonic-copepod-acartia-tonsa-4433lrfepr.pdf

Bioenergetics of the planktonic copepod Acartia tonsa: relation between feeding, egg production and respiration, and composition of specific dynamic action

For more than 200 years, the metabolic response that accompanies meal digestion has been characterized, theorized, and experimentally studied. Historically labeled “specific dynamic action” or “SDA”, this physiological phenomenon represents the energy expended on all activities of the body incidental to the ingestion, digestion, absorption, and assimilation of a meal. Specific dynamic action or a component of postprandial metabolism has been quantified for more than 250 invertebrate and vertebrate species. Characteristic among all of these species is a rapid postprandial increase in metabolic rate that upon peaking returns more slowly to prefeeding levels. The average maximum increase in metabolic rate stemming from digestion ranges from a modest 25% for humans to 136% for fishes, and to an impressive 687% for snakes. The type, size, composition, and temperature of the meal, as well as body size, body composition, and several environmental factors (e.g., ambient temperature and gas concentration) can each significantly impact the magnitude and duration of the SDA response. Meals that are large, intact or possess a tough exoskeleton require more digestive effort and thus generate a larger SDA than small, fragmented, or soft-bodied meals. Differences in the individual effort of preabsorptive (e.g., swallowing, gastric breakdown, and intestinal transport) and postabsorptive (e.g., catabolism and synthesis) events underlie much of the variation in SDA. Specific dynamic action is an integral part of an organism’s energy budget, exemplified by accounting for 19–43% of the daily energy expenditure of free-ranging snakes. There are innumerable opportunities for research in SDA including coverage of unexplored taxa, investigating the underlying sources, determinants, and the central control of postprandial metabolism, and examining the integration of SDA across other physiological systems.

/pdf/specific-dynamic-action-a-review-of-the-postprandial-18gdectymp.pdf

Specific dynamic action: a review of the postprandial metabolic response

1.

Field measurements of hearing in the cod,Gadus morhua L., have shown that these fish are sensitive to pure tones in the frequency range from 30 to 470 Hz with greatest sensitivity in the range 60 to 310 Hz. At the most sensitive frequencies the mean thresholds varied between -18 and -26 dB/μbar (Fig. 4).




2.

Variation in the thresholds at most frequencies was related to changes in the level of ambient sea noise (Figs. 5–7). Only in calm sea conditions were unmasked thresholds obtained. The masking effect of noise was confirmed by raising the level artificially. The thresholds increased in proportion to the increase in noise level.




3.

The thresholds were largely independent of the distance of the sound source over the range from 1.7 to 50m, suggesting that cod are sensitive to acoustic pressure. However, a changeover to particle displacement sensitivity was noted at frequencies below 50 Hz when the sound source was moved to within l m of the fish (Fig. 9).




4.

It is concluded that the swimbladder plays an accessory role in hearing. Differences obtained in the thresholds at different sound source distances may be explained in terms of the displacement sensitivity of the otolith organs. These respond to displacements re-radiated from the swimbladder in the far-field, and to the greater incident displacement in the near-field at very low frequencies.

A field study of hearing in the cod,Gadus morhua L.

It has long been known that sounds are important to fish Isaac Walton advised anglers ‘to be patient and forbear swearing, lest they be heard’ A wide range of species, including many that are commercially valuable, emit sounds as part of their social behaviour (Tavolga 1976), and several species have been shown to be acutely sensitive to underwater sounds However, before we consider the acoustical behaviour of fish in more detail, we need to understand what sound is, how sounds are created, and how they are transmitted through water

Underwater Sound and Fish Behaviour

The hearing of the salmon, Salmo salar L., was studied by means of a cardiac conditioning technique. Fish were trained to show a slowing of the heart, on hearing a sound, in anticipation of a mild electric shock applied later. The minimum sound level to which the fish would respond was determined for a range of pure tones, both in the sea, and in the laboratory. The fish responded only to low frequency tones (below 380 Hz), and particle motion, rather than sound pressure, proved to be the relevant stimulus. The sensitivity of the fish to sound was not affected by the level of sea noise under natural conditions but hearing is likely to be masked by ambient noise in a turbulent river. Sound measurements made in the River Dee, near Aberdeen, lead to the conclusion that salmon are unlikely to detect sounds originating in air, but that they are sensitive to substrate borne sounds. Compared with the carp and cod the hearing of the salmon is poor, and more like that of the perch and plaice.

The hearing of the Atlantic Salmon, Salmo salar

/pdf/the-effects-of-noise-on-aquatic-life-49zmj5l485.pdf

The effects of noise on aquatic life

The energetic costs associated with feeding by juvenile cod were determined by means of an open-circuit respirometer. Fish acclimated to several temperatures (7, 10, 15 and 18°C) were kept at natural lighting levels, and fed inside their individual respirometers. They consumed a diet compounded from natural foods, at five different ration levels, their oxygen consumption being monitored continually over an 11–16 day period.



After each meal the rate of oxygen consumption increased to above the pre-feeding level, reaching a peak 8–10 h later. With each successive meal the oxygen consumption showed a cumulative increase, reaching a maximum usually after the last meal.



The elevation in metabolic rate associated with feeding was dependent upon ration size, increasing linearly as the food intake increased. The effect was also dependent upon temperature; for fish fed to satiation the total energy cost was equivalent to 11.9, 10.9, 16.4 and 17.1% of the ingested energy at 7, 10, 15 and 18°C respectively. For resting satiated fish the rate of oxygen consumption was close to the maximum rate for active fish.

Anthony D. Hawkins

Papers

A field study of hearing in the cod,Gadus morhua L.

Underwater Sound and Fish Behaviour

The hearing of the Atlantic Salmon, Salmo salar

The effects of noise on aquatic life

Energetic costs at different levels of feeding in juvenile cod, Gadus morhua L.