3,725 research outputs found

    Evaluation of brewers' dried grains in cattle diets

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    Digitized 2007 AES MoU.Includes bibliographical references (pages 37-39)

    Enhanced winnings in a mixed-ability population playing a minority game

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    We study a mixed population of adaptive agents with small and large memories, competing in a minority game. If the agents are sufficiently adaptive, we find that the average winnings per agent can exceed that obtainable in the corresponding pure populations. In contrast to the pure population, the average success rate of the large-memory agents can be greater than 50 percent. The present results are not reproduced if the agents are fed a random history, thereby demonstrating the importance of memory in this system.Comment: 9 pages Latex + 2 figure

    Comparison of the Symbiotic Fauna of the Family Plethodontidae in the Ouachita Mountains of Western Arkansas

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    During the spring of 1985, 101 salamanders representing six host species (29 Plethodon ouachitae, 25 P. caddoensis, 6 P. fourchensis, 23 P. serratus, 13 Desmognathus brimleyorum, and 5 P. glutinosus glutinosus) were collected from six localities in three counties in Arkansas (Polk, Scott, and Montgomery) and examined for symbionts. With the exception of Hannemania dunni, all symbionts recovered from the first five species listed constitute new host records, and the endoparasitic fauna in all species establish new locality records. Examinations revealed one or more species of parasites in 82% of the hosts. Eight species of symbionts (3 nematode, 1 trematode, 1 cestode, 1 protozoan, 1 arthropod, and 1 cystacanth acanthocephalon) were recovered. Conclusions are based on the three host species examined in the largest numbers. Thelandros magnavulvularis and H. dunni were the most commonly occurring parasites, found in five and four host species respectively. Cepedietta michiganensis was restricted to P. ouachitae and Brachycoelium storeriae to P. caddoensis. Hannemania dunni was absent in P. serratus

    Multi-Agent Complex Systems and Many-Body Physics

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    Multi-agent complex systems comprising populations of decision-making particles, have many potential applications across the biological, informational and social sciences. We show that the time-averaged dynamics in such systems bear a striking resemblance to conventional many-body physics. For the specific example of the Minority Game, this analogy enables us to obtain analytic expressions which are in excellent agreement with numerical simulations.Comment: Accepted for publication in Europhysics Letter

    A \u3cem\u3eDendroctonus\u3c/em\u3e Bark Engraving (Coleoptera: Scolytidae) From A Middle Eocene \u3cem\u3eLarix\u3c/em\u3e (Coniferales: Pinaceae): Early Or Delayed Colonization?

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    An engraving made by a scolytid bark beetle, assigned to the genus Dendroctonus of the tribe Tomicini, has been identified on a mummified, middle Eocene (45 Ma) specimen of Larix altoborealis wood from the Canadian High Arctic. Larix altoborealis is the earliest known species of Larix, a distinctive lineage of pinaceous conifers that is taxonomically identifiable by the middle Eocene and achieved a broad continental distribution in northern North America and Eurasia during the late Cenozoic. Dendroctonus currently consists of three highly host-specific lineages that have pinaceous hosts: a basal monospecific clade on Pinoideae (Pinus) and two sister clades that consist of a speciose clade associated exclusively with Pinoideae and six species that breed overwhelmingly in Piceoideae (Picea) and Laricoideae (Pseudotsuga and Larix). The middle Eocene engraving in L. altoborealis represents an early member of Dendroctonus that is ancestral to other congeneric species that colonized a short-bracted species of Larix. This fossil occurrence, buttressed by recent data on the phylogeny of Pinaceae subfamilies and Dendroctonus species, indicates that there was phylogenetically congruent colonization by these bark-beetle lineages of a Pinoideae + (Piceoideae + Laricoideae) host-plant sequence. Based on all available evidence, an hypothesis of a geochronologically early invasion during the Early Cretaceous is supported over an alternative view of late Cenozoic cladogenesis by bark beetles onto the Pinaceae. These data also suggest that host-plant chemistry may be an effective species barrier to colonization by some bark-beetle taxa over geologically long time scales

    Incorporating Inertia Into Multi-Agent Systems

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    We consider a model that demonstrates the crucial role of inertia and stickiness in multi-agent systems, based on the Minority Game (MG). The inertia of an agent is introduced into the game model by allowing agents to apply hypothesis testing when choosing their best strategies, thereby reducing their reactivity towards changes in the environment. We find by extensive numerical simulations that our game shows a remarkable improvement of global cooperation throughout the whole phase space. In other words, the maladaptation behavior due to over-reaction of agents is removed. These agents are also shown to be advantageous over the standard ones, which are sometimes too sensitive to attain a fair success rate. We also calculate analytically the minimum amount of inertia needed to achieve the above improvement. Our calculation is consistent with the numerical simulation results. Finally, we review some related works in the field that show similar behaviors and compare them to our work.Comment: extensively revised, 8 pages, 10 figures in revtex

    A thermal model for adaptive competition in a market

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    New continuous and stochastic extensions of the minority game, devised as a fundamental model for a market of competitive agents, are introduced and studied in the context of statistical physics. The new formulation reproduces the key features of the original model, without the need for some of its special assumptions and, most importantly, it demonstrates the crucial role of stochastic decision-making. Furthermore, this formulation provides the exact but novel non-linear equations for the dynamics of the system.Comment: 4 RevTeX pages, 3 EPS figures. Revised versio
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