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Author Bergstrom, C.T.; Lachmann, M.
Title Signaling among relatives. III. Talk is cheap Type Journal Article
Year 1998 Publication Proceedings of the National Academy of Sciences of the United States of America Abbreviated Journal Proc. Natl. Acad. Sci. U.S.A.
Volume (down) 95 Issue 9 Pages 5100-5105
Keywords Animal Communication; Animals; Costs and Cost Analysis; *Evolution; Interpersonal Relations; Models, Biological
Abstract The Sir Philip Sidney game has been used by numerous authors to show how signal cost can facilitate honest signaling among relatives. Here, we demonstrate that, in this game, honest cost-free signals are possible as well, under very general conditions. Moreover, these cost-free signals are better for all participants than the previously explored alternatives. Recent empirical evidence suggests that begging is energetically inexpensive for nestling birds; this finding led some researchers to question the applicability of the costly signaling framework to nestling begging. Our results show that cost-free or inexpensive signals, as observed empirically, fall within the framework of signaling theory.
Address Department of Biological Sciences, Stanford University, Stanford, CA 94305, USA. carl@charles.stanford.edu
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ISSN 0027-8424 ISBN Medium
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Notes PMID:9560235 Approved no
Call Number refbase @ user @ Serial 561
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Author Dusek, J.A.; Eichenbaum, H.
Title The hippocampus and memory for orderly stimulus relations Type Journal Article
Year 1997 Publication Proceedings of the National Academy of Sciences of the United States of America Abbreviated Journal Proc. Natl. Acad. Sci. U.S.A.
Volume (down) 94 Issue 13 Pages 7109-7114
Keywords Animals; Attention; Discrimination (Psychology)/physiology; Hippocampus/anatomy & histology/*physiology; Male; Memory/*physiology; Rats
Abstract Human declarative memory involves a systematic organization of information that supports generalizations and inferences from acquired knowledge. This kind of memory depends on the hippocampal region in humans, but the extent to which animals also have declarative memory, and whether inferential expression of memory depends on the hippocampus in animals, remains a major challenge in cognitive neuroscience. To examine these issues, we used a test of transitive inference pioneered by Piaget to assess capacities for systematic organization of knowledge and logical inference in children. In our adaptation of the test, rats were trained on a set of four overlapping odor discrimination problems that could be encoded either separately or as a single representation of orderly relations among the odor stimuli. Normal rats learned the problems and demonstrated the relational memory organization through appropriate transitive inferences about items not presented together during training. By contrast, after disconnection of the hippocampus from either its cortical or subcortical pathway, rats succeeded in acquiring the separate discrimination problems but did not demonstrate transitive inference, indicating that they had failed to develop or could not inferentially express the orderly organization of the stimulus elements. These findings strongly support the view that the hippocampus mediates a general declarative memory capacity in animals, as it does in humans.
Address Department of Psychology, Boston University, 64 Cummington Street, Boston, MA 02215, USA
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ISSN 0027-8424 ISBN Medium
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Notes PMID:9192700 Approved no
Call Number refbase @ user @ Serial 607
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Author Ballew, R.M.; Sabelko, J.; Gruebele, M.
Title Direct observation of fast protein folding: the initial collapse of apomyoglobin Type Journal Article
Year 1996 Publication Proceedings of the National Academy of Sciences of the United States of America Abbreviated Journal Proc. Natl. Acad. Sci. U.S.A.
Volume (down) 93 Issue 12 Pages 5759-5764
Keywords Animals; Apoproteins/*chemistry; Circular Dichroism; Horses; Kinetics; Muscle, Skeletal/chemistry; Myoglobin/*chemistry; *Protein Folding; Spectrometry, Fluorescence; Spectrophotometry, Infrared; Temperature
Abstract The rapid refolding dynamics of apomyoglobin are followed by a new temperature-jump fluorescence technique on a 15-ns to 0.5-ms time scale in vitro. The apparatus measures the protein-folding history in a single sweep in standard aqueous buffers. The earliest steps during folding to a compact state are observed and are complete in under 20 micros. Experiments on mutants and consideration of steady-state CD and fluorescence spectra indicate that the observed microsecond phase monitors assembly of an A x (H x G) helix subunit. Measurements at different viscosities indicate diffusive behavior even at low viscosities, in agreement with motions of a solvent-exposed protein during the initial collapse.
Address School of Chemical Sciences and Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana, 61801, USA
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ISSN 0027-8424 ISBN Medium
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Notes PMID:8650166 Approved no
Call Number Equine Behaviour @ team @ Serial 3798
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Author Hauser, M.D.; Kralik, J.; Botto-Mahan, C.; Garrett, M.; Oser, J.
Title Self-recognition in primates: phylogeny and the salience of species-typical features Type Journal Article
Year 1995 Publication Proceedings of the National Academy of Sciences of the United States of America Abbreviated Journal Proc. Natl. Acad. Sci. U.S.A.
Volume (down) 92 Issue 23 Pages 10811-10814
Keywords Animals; *Behavior, Animal; *Cognition; Discrimination (Psychology); Exploratory Behavior; Female; Hair Color; Male; Phylogeny; Psychology, Comparative; Research Design; Saguinus/*psychology; *Self Concept; Species Specificity; Touch; *Visual Perception
Abstract Self-recognition has been explored in nonlinguistic organisms by recording whether individuals touch a dye-marked area on visually inaccessible parts of their face while looking in a mirror or inspect parts of their body while using the mirror's reflection. Only chimpanzees, gorillas, orangutans, and humans over the age of approximately 2 years consistently evidence self-directed mirror-guided behavior without experimenter training. To evaluate the inferred phylogenetic gap between hominoids and other animals, a modified dye-mark test was conducted with cotton-top tamarins (Saguinus oedipus), a New World monkey species. The white hair on the tamarins' head was color-dyed, thereby significantly altering a visually distinctive species-typical feature. Only individuals with dyed hair and prior mirror exposure touched their head while looking in the mirror. They looked longer in the mirror than controls, and some individuals used the mirror to observe visually inaccessible body parts. Prior failures to pass the mirror test may have been due to methodological problems, rather than to phylogenetic differences in the capacity for self-recognition. Specifically, an individual's sensitivity to experimentally modified parts of its body may depend crucially on the relative saliency of the modified part (e.g., face versus hair). Moreover, and in contrast to previous claims, we suggest that the mirror test may not be sufficient for assessing the concept of self or mental state attribution in nonlinguistic organisms.
Address Department of Anthropology, Harvard University, Cambridge, MA 02138, USA
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ISSN 0027-8424 ISBN Medium
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Notes PMID:7479889 Approved no
Call Number Equine Behaviour @ team @ Serial 2825
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Author Hostikka, S.L.; Eddy, R.L.; Byers, M.G.; Hoyhtya, M.; Shows, T.B.; Tryggvason, K.
Title Identification of a distinct type IV collagen alpha chain with restricted kidney distribution and assignment of its gene to the locus of X chromosome-linked Alport syndrome Type Journal Article
Year 1990 Publication Proceedings of the National Academy of Sciences of the United States of America Abbreviated Journal Proc. Natl. Acad. Sci. U.S.A.
Volume (down) 87 Issue 4 Pages 1606-1610
Keywords Amino Acid Sequence; Base Sequence; Chromosome Mapping; Cloning, Molecular; Collagen/*genetics; Epitopes/analysis; Female; Fluorescent Antibody Technique; Gene Library; *Genes; Humans; Immunoblotting; Kidney/cytology/*metabolism; Macromolecular Substances; Molecular Sequence Data; Nephritis, Hereditary/*genetics; Oligopeptides/chemical synthesis/immunology; Placenta/metabolism; Pregnancy; Restriction Mapping; Sequence Homology, Nucleic Acid; *X Chromosome
Abstract We have identified and extensively characterized a type IV collagen alpha chain, referred to as alpha 5(IV). Four overlapping cDNA clones isolated contain an open reading frame for 543 amino acid residues of the carboxyl-terminal end of a collagenous domain, a 229-residue carboxyl-terminal noncollagenous domain, and 1201 base pairs coding for a 3' untranslated region. The collagenous Gly-Xaa-Yaa repeat sequence has five imperfections that coincide with those in the corresponding region of the alpha 1(IV) chain. The noncollagenous domain has 12 conserved cysteine residues and 83% and 63% sequence identity with the noncollagenous domains of the alpha 1(IV) and alpha 2(IV) chains, respectively. The alpha 5(IV) chain has less sequence identity with the putative bovine alpha 3(IV) and alpha 4(IV) chains. Antiserum against an alpha 5(IV) synthetic peptide stained a polypeptide chain of about 185 kDa by immunoblot analysis and immunolocalization of the chain in human kidney was almost completely restricted to the glomerulus. The gene was assigned to the Xq22 locus by somatic cell hybrids and in situ hybridization. This may be identical or close to the locus of the X chromosome-linked Alport syndrome that is believed to be a type IV collagen disease.
Address Biocenter, University of Oulu, Finland
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ISSN 0027-8424 ISBN Medium
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Notes PMID:1689491 Approved no
Call Number Equine Behaviour @ team @ Serial 5291
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