761 research outputs found

    A Shift in Healthcare: Why Do Physicians Choose Health System Employment Over Independent Practice?

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    This thesis analyzes the movement of physician employment from independent practice toward health system employment within the United States healthcare industry through a non-statistical meta-analysis of current literature. This work sets the foundation for current physician employment decisions

    Comparison of Standard Soil Amendments and Calcined Clay on Crop Yields in an Urban Garden at the University of North Carolina Asheville, Asheville, North Carolina

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    Implementation of amended soils at the Rhoades Property Garden, a campus garden of the University of North Carolina Asheville was investigated for greater land use efficiency and increase of plant growth. Calcined clay arestable soil amendments that improve soil quality through increased cation exchange capacity, increased microbial activity, nutrient retention, and water holding capacity all of which increase plant yield. Two calcined clay amended beds (one constructed the year prior and one newly built) and one standard soil (control) bed were planted with comparable planting schemes of eggplant (Solanum melongena), tomato (Solanum lycopersicum), pepper (Capsicum), and tomatillo (Physalis philadelphica) and received the same amendments, pruning, and watering. Summer harvest yields were calculated for total fruit volume and mass, as well as root mass per bed. Data wereanalyzed using SAS, ANOVA, paired T-tests and a Tukey post-hoc test. Significant difference in mean eggplant yield as measured by harvest date was found (p=0.0182). Comparisons of volume/mass per vegetable and among variety of vegetable were insignificant. The experiment will be extended to test for statistically significant differencein production and to include biochar

    Representing Homeless ness in America: Portrayls of Homelessness in Popular Culture and the Stories Homeless People Tell About Themselves

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    Portrayals of American homelessness and its causes issue from different parts of society,from popular culture in the form of films and newspaper articles to the views of homeless individuals themselves. While the former media reach broad audiences and may influence cultural conceptions of homelessness, the latter are rarely broadcast so widely. Unlike the‘external’ representations of homelessness created for entertainment and the dissemination ofinformation, ‘internal’ depictions of indigency from those experiencing it are complex,idiosyncratic stories about individual cases of homelessness. These different kinds of portrayals are created for decidedly different purposes, yet it is an assumption of this paper that each type of depiction has an influence on the broader cultural conception of homelessness in the U.S.A. Thus each will be examined for the way homelessness is presented, rather than the reason it is presented. The stories of the indigent are arguably the most important source of information for understanding the current nature of homelessness in America, yet the general public is often most-informed on the ‘social problem’ of homelessness through the aforementioned media. Howdo these two types of stories about homelessness differ, and to what effect? It is the aim of this study to investigate and compare some of the different kinds of stories told about homelessness in America

    Paradoxical effects of experience with food size and flavour in golden hamsters (Mesocricetus auratus)

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    Young hamsters were reared until 35 days of age with access to food pellets of one of three sizes. They were then given a choice between the three sizes of pellets: the familiar size and two unfamiliar sizes, and the rate of energy gain from eating pellets of each size was established. Contrary to predictions from optimal foraging theory, the animals chose pellets of the most unfamiliar size, not the most profitable ones. A taste preference study was conducted to see whether hamsters respond to taste cues as do other rodents. The animals showed a preference for familiar flavours. The results of these studies suggest that the sorts of experiences animals have had with food must be considered in any account of food choice behaviour

    Developmental explanation and the ontogeny of birdsong: Nature/nurture redux

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    Despite several decades of criticism, dichotomous thinking about behavioral development (the view that the behavioral phenotype can be partitioned into inherited and acquired components) remains widespread and influential. This is particularly true in study of birdsong development, where it has become increasingly common to diagnose songs, elements of songs, or precursors of songs (song templates) as either innate or learned on the basis of isolation-rearing experiments. The theory of sensory templates has encouraged both the dichotomous approach (by providing a role for genetic blueprints to guide song learning) and an emphasis on structural rather than functional aspects of song development. As a result, potentially important lines of investigation have been overlooked and the interpretation of existing data is often flawed. Evidence for a genetic origin of behavioral differences is frequently interpreted as evidence for the genetic determination of behavioral characters. The technique of isolation rearing remains the methodology of choice for many investigators, despite the fact that it offers only a rather crude analysis of the contribution of experience to song development and provides no information at all about genetic contributions to development. The latter could in principle be elucidated by the application of developmental-genetic techniques, but it is unlikely that these can easily be applied to the study of birdsong. Because developmental questions are so often posed in terms of the learned—innate dichotomy, "experience"istaken to be synonymous with "learning" and the possible role of nonobvious contributions to song development has largely been ignored. An alternative approach, based on Daniel Lehrman's interactionist theory of development, permits a more thorough appreciation of the problems that have yet to be addressed, and provides a more secure conceptual foundation for theories of song development

    Development of visual species identification in ducklings: What is the role of imprinting?

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    The phenomenon of imprinting (a rapid form of exposure learning) is widely presumed to underlie the formation of normal, species-typical social preferences in precocial birds. To determine whether this is in fact the case, 24-h-old domestic and semi-wild mallard ducklings (Anas platyrhynchos) were allowed to follow a stuffed hen of one of three sympatric waterfowl species for 20 min. The models used were mallard, redhead (Aythya americana), and pintail (Anas acuta) hens. When later tested for their preference for the familiar hen in simultaneous choice tests with one of the other two stuffed models, only those birds trained with the Mallard and tested with the Mallard and Pintail models (designated the Mallard versus Pintail group) showed a preference for the familiar model. (That preference was shown by both domestic and semi-wild ducklings.) In none of the other three groups (Mallard versus Redhead, Redhead versus Mallard, and Pintail versus Mallard) was the imprinting procedure effective in producing a preference for the familiar model. When other ducklings were similarly trained with either the Mallard model, a red-and-white-striped box, or a green styrofoam ball, a preference for the familiar model was found in all four groups (.Mallard versus Red Box, Red Box versus Mallard, Red Box versus Green Ball, and Green Ball versus Red Box). Increasing the length of the training period from 20 min to 2 h and to 24 h did not produce a preference for the familiar Mallard over the unfamiliar Redhead. These results raise some doubt that imprinting as currently conceived is the behavioural mechanism of visual species identification as it occurs in nature

    Theoretical Considerations in the Adaptation of Animal Communication Systems

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    Using concepts drawn from semiotic, the general theory of signs, and from the mathematical theory of communication, a theoretical framework is developed within which the problems relating to communication system adaptation may be defined and models of such adaptation constructed. The relationship between the semiotical notions of qualisign and legisign is used to define a concept of tolerance space that permits the statistical concept of equivocation to take on physical dimensions in the analysis of natural communication systems. For each of three central properties of the communication system (entropy, equivocation and semantic-pragmatic relations) the components of the system that determine the property are identified and the ways in which these components might adapt to environmental changes are discussed

    Middle Temporal Cortical Visual Area Visuospatial Function in Galago senegalensis

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    Bushbabies with lesions restricted to the middle temporal (MT) area and animals with larger extrastriate lesions including area MT were compared with normal control animals on tests of visuospatial localization and discrimination learning. Ablation of area MT was sufficient to produce impairments in directing behavior appropriately on the basis of visuospatial cues. Extension of the lesion into areas 18 and 19 produced more profound deficits. Retardation in learning a stripe discrimination problem was correlated with the extent of damage to the geniculostriate system. It is hypothesized that area MT is important in achieving and maintaining fixation on a target whereas cortical areas 18 and 19 are necessary for establishing the location of stimulation in visual space

    Neophenogenesis: A developmental theory of phenotypic evolution

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    An important task for evolutionary biology is to explain how phenotypes change over evolutionary time. Neo-Darwinian theory explains phenotypic change as the outcome of genetic change brought about by natural selection. In the neo-Darwinian account, genetic change is primary; phenotypic change is a secondary outcome that is often given no explicit consideration at all. In this article, we introduce the concept of neophenogenesis: a persistent, transgenerational change in phenotypes over evolutionary time. A theory of neophenogenesis must encompass all sources of such phenotypic change, not just genetic ones. Both genetic and extra-genetic contributions to neophenogenesis have their effect through the mechanisms of development, and developmental considerations, particularly a rejection of the commonly held distinction between inherited and acquired traits, occupy a central place in neophenogenetic theory. New phenotypes arise because of a change in the patterns of organism-environment interaction that produce development in members of a population. So long as these new patterns of developmental interaction persist, the new phenotype(s) will also persist. Although the developmental mechanisms that produce the novel phenotype may change, as in the process known as "genetic assimilation", such changes are not necessary in order for neophenogenesis to occur, because neophenogenetic theory is a theory of phenotypic, not genetic, change

    Three pioneers of American comparative psychology, 1843-1890: Lewis Henry Morgan, John Bascom, and Joseph LeConte

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    Abstract: Scientific comparative psychology in America dates from the mid-1890s, but there is a body of earlier literature on the topic, written during a period of theistic debates over Darwinian evolution. The anthropologist Lewis H. Morgan rejected instinct as an explanation of animal behavior in 1843 and defended the mental similarities between animals and humans, although he was not an evolutionist. John Bascom's textbook Comparative Psychology (1878) is the earliest American work to use that title, and its theistic approach anticipates some arguments found in much later evolutionary works. Beginning in 1860, the geologist Joseph LeConte, who is well known for defending the compatibility of evolution and religion, wrote several articles in which he outlined a comparative evolutionary approach to psychological problems. However, these writers did not establish a coherent research tradition and were ignored by the "New Psychologists" of the 1880s
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