2,620 research outputs found
Chrosomus erythrogaster and C. eos (Ostichtnyes: Cyprinidae): taxonomy, distribution, ecology
No full textPhillips, Gary L.. (1968). Chrosomus erythrogaster and C. eos (Ostichtnyes: Cyprinidae): taxonomy, distribution, ecology. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/193826
Beyond selection: optimal ingestion rate as a function of food value
No full textA simple model based on microphagous feeders (animals which process their food items in bulk with little chance of selecting food items on an individual basis) has been developed to predict how ingestion rate should vary with food quality if the net time rate of gain of some measure of food quality, say energy, is to be maximized. Three variants of the model were considered, in which absorption efficiency (1) was constant, (2) decreased linearly with increased ingestion rate, or (3) decreased exponentially. The optimal ingestion rate, which maximized the net rate of energy gain, depended on food quality and increased on higher quality foods. For certain parameter values, constantly maintaining the maximum ingestion rate resulted in maximal net energy gain. Experimental results from the literature on a variety of animals are not in consistent accord with these predictions. It seems likely that uncontrolled and confounding variables, such as food composition or palatability, may obscure the effects of food quality on ingestion rate.Peer reviewe
Optimal foraging by deposit-feeding invertebrates: roles of particle size and organic coating
No full textFeeding experiments were conducted on marine, deposit-feeding benthic invertebrates to test the predictions of an optimal foraging model. Food item selection based on sediment particle size and presence or absence of an organic coating on particles was investigated. Animals displaying a wide range of feeding mechanisms were studied in particle size-selection experiments using artificial sediment of closely controlled size composition. Nine of 10 species from 4 phyla ingested smaller particles in greater proportions than the particles were present in the sediment. In experiments where animals fed on a mixture of two particle types, one with and one without a surface protein coating, 6 of 7 species from 3 phyla ingested preferentially the protein-coated beads. While these trends of selection of smaller particles and protein-coated particles follow qualitatively the predictions of the optimal foraging model, the animals did not ingest exclusively the preferred particle types. Mechanics of particle handling rather than behavioral responses to particle characteristics appear to offer the better explanation for the observed selection patterns. In particular, the results support strongly the recently proposed role of mucous adhesion in particle selection by deposit feeders.
These and other results from studies of deposit feeders suggest that factors in addition to food item selection must be considered when testing the assumptions and predictions of optimal foraging theory. Specifically, feeding energetics arc also affected by postfood-selection processes such as variation of ingestion rate. Furthermore, the effects of abiotic environmental factors on foraging behavior cannot be overlooked in evaluating the optimality of foraging behavior; variable water velocity affected differently the particle size selectivity of 3 sympatric polychaete species in these studies.Peer reviewedPosted with permission from Springer Nature
Variable ingestion rate and its role in optimal foraging behavior of marine deposit feeders
No full textTests of optimal foraging theory have focused generally on food item selection by mobile, high-trophic-level predators. Deposit-feeding invertebrates are aquatic organisms with limited mobility and hence limited ability to forage actively for food-rich patches. In addition, there is little evidence for a major role of behaviorally mediated food item choice in these animals, and growing evidence of mechanical limitations in food particle choice. Given such limited food-selection ability, varying ingestion rate in response to changes in food value is likely to be an important animal response affecting feeding energetics. A previously developed optimal foraging model predicted that ingestion rate and food value should covary positively in order to maximize net time rate of energy gain. To test this general prediction, we fed three species of deposit-feeding polychaetes artificial sediments which varied only in protein content (food value); other physical and chemical properties which might affect ingestion rate were kept constant. In support of the model, ingestion rates increased as protein levels increased.Peer reviewe
Lipid class and glycogen content of the lugworm Abarenicola pacifica in relation to age, growth rate and reproductive condition
No full textWe measured the levels of lipid classes (wax esters, triacylglycerides, free fatty acids, sterols, phospholipids) and levels of glycogen in a population of Abarenicola pacifica over a one-year period beginning shortly after recruitment. Glycogen and lipid contents were unrelated to growth rates as estimated by changes in average size of individuals in the cohort. There was no indication of seasonality in levels of any component, consistent with the hypothesis of Slobodkin and Richman that animals living in environments where food supplies are likely to be stable, such as subsurface deposit-feeders like A. pacifica, do not accumulate energy reserves. Instead, glycogen content increased gradually and most lipid classes decreased gradually over time. A notable exception was the triacylglyceride content, which showed a large increase associated with the formation of eggs. Triacylglyceride levels in older A. pacifica and in two other species of deposit-feeding polychaetes showed similar trends. Measurement of triacylglyceride levels may provide an additional objective method, supplementing egg counts and egg size, of quantifying reproductive effort in deposit-feeders.Peer reviewedPosted with permission from Springer Nature
Cwbr Author Interview: The Union War
No full textInterview with Dr. Gary Gallagher, John L. Nau III Professor of History at the University of Virginia Interviewed by Nathan Buman
Civil War Book Review (CWBR): Today, I\u27m delighted to be joined by Gary Gallagher who is John L. Nau III Professor of History at the University of Virginia to discuss his most recent book The Union War. Professor Gallagher, thank you for talking with us today. Gary Gallagher (GG): Thanks for inviting me
The Biology and Immature Stages of Zygogramma Suturalis (Fabricius) (Coleoptera: Chrysomelidae)
No full textAuthor Institution: Department of Biological Sciences, Kent State UniversityPIPER, GARY L. The Biology and Immature Stages of Zygogramma suturalis (Fabricius) (Coleoptera: Chrysomelidae). Ohio J. Sci. 75(1): 19, 1975
Image de Gary entre monde réel et fictif
No full textOur study object turns around La vie devant soi, a novel by Romain Gary under the alias name of Emile Ajar. We try to shows the importance of the relation linking Gary with his fictional tale, because inside his rapport the author constructs his image, which is the ethos by which he can represent himself and creating a fictional character carrying the story of his life. We also exposes the importance of the presence of the metalepses inside the fictional literary text that seeks to identify the nature of the author�s alienation in relation with his work and his readers and interrogates about the role that the fictional literature plays in the construction of the literary discourse.Notre présente étude porte sur La vie devant soi, un roman signé par Emile Ajar que Romain Gary a pris comme pseudonyme et vise à montrer l�importance du lien unissant Gary avec son récit de fiction car c�est à l�intérieur de ce rapport que se construit l�image de soi de l�auteur, à savoir l�ethos par lequel il peut s�auto-représenter, tout en créant un personnage fictif portant et véhiculant l�histoire de sa vie. Nous soulevons ici l�importance de la présence de la métalepse à l�intérieur du texte littéraire de fiction qui cherche à identifier la nature de l�appartenance de l�auteur par rapport à son oeuvre et à ses lecteurs et s�interroge sur le rôle que joue l�écriture fictive dans la construction d�un discours littéraire
A "Labyrinth of Linkages" in Tolstoy's "Anna Karenina"
No full textThe renowned Russian writer Leo Tolstoy created a realistic masterpiece in Anna Karenina (1878). In the same work, moreover, he utilized allegory and symbol to an extent and at a level of sophistication unknown in his other works. In Browning’s study, the author identifies and analyzes previously unnoticed or only briefly mentioned “linkages and keystones” found in two highly developed clusters of symbols, arising from Anna’s momentous train ride and peasant nightmares, and of allegories, rooted in Vronsky’s disastrous steeplechase. Within this labyrinth of symbol and allegory lies embedded much of the novel’s most significant meaning. This study will be of particular interest to students and scholars of Russian literature, Tolstoy, symbol, allegory, structuralism, and moral criticism
Implications Of Aggregate Demand Elasticity For The Phillips Curve
No full textWhile the general relationship between the aggregate supply curve and the Phillips curve is recognized, the importance of aggregate demand and, in particular, aggregate demand elasticity, for the inflation-unemployment relationship has been untreated. We believe, however, that the elasticity of aggregate demand with respect to the general price level does have some significance for the short-run Phillips curve since, on a general level, the economy\u27s equilibrium price level, inflation rate, real gross domestic product, and unemployment rate are determined jointly by aggregate supply and aggregate demand. The primary purpose of this paper then is to demonstrate with a graphical analysis the implications of aggregate demand elasticity for the Phillips curve
- …
