262 research outputs found

    Minimum inhibitory concentration of essential oils on Candida fungus

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    SPECIES COMPOSITION, FOOD HABITS, AND THE ECONOMIC AND ECOLOGIC IMPACT OF WINTER BLACKBIRD FLOCKS

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    Crop depredation by blackbirds (Icteridae) and Starlings (sturnus vulgaris) in North America has long prompted experimentation with control techniques. These efforts have been centered in the northeast and northcentral United States where concentrated cultivation of vulnerable crops coincides with the location where flocks of blackbirds congregate in the fall prior to their migration south (Stone, et al., 1972; Wiens and Dyer, 1975). In these areas the high cost and logistic impracticality of implementing widespread controls has suggested the need for modifying agricultural practices instead (Wiens and Dyer, 1975). More recently, attention has been focused farther south, particularly in Kentucky and Tennessee where winter roosts of mixed flocks of blackbirds and Starlings commonly number over several million birds. These highly localized concentrations have prompted concern for both agricultural damage and danger to human health (Department of Army, 1975). A major difference between the problem in the South and that farther north is that in the South the birds present themselves as much more accessible targets for control measures. By virtue of their tremendous concentrations they make the potential for large scale extermination very real. It is quite conceivable that a significant proportion of the entire North American populations of these birds could be eliminated if extermination efforts were maintained for several years at the major winter roosts. Before such extermination is allowed to proceed, a number of questions must be answered. These can be divided into two areas. The first area deals with whether or not the control measures are actually justified--how much agricultural damage is done by the birds and how real is their threat to human health? The second area of questioning concerns the environmental impact of both the control measures themselves as well as the effect of suddenly removing such large numbers of birds from the ecosystem. This paper presents the results of a preliminary study aimed not at answering these questions so much as providing some insight into the factors which must be considered if accurate answers are to be obtained

    SPECIES COMPOSITION, FOOD HABITS, AND THE ECONOMIC AND ECOLOGIC IMPACT OF WINTER BLACKBIRD FLOCKS

    Get PDF
    Crop depredation by blackbirds (Icteridae) and Starlings (sturnus vulgaris) in North America has long prompted experimentation with control techniques. These efforts have been centered in the northeast and northcentral United States where concentrated cultivation of vulnerable crops coincides with the location where flocks of blackbirds congregate in the fall prior to their migration south (Stone, et al., 1972; Wiens and Dyer, 1975). In these areas the high cost and logistic impracticality of implementing widespread controls has suggested the need for modifying agricultural practices instead (Wiens and Dyer, 1975). More recently, attention has been focused farther south, particularly in Kentucky and Tennessee where winter roosts of mixed flocks of blackbirds and Starlings commonly number over several million birds. These highly localized concentrations have prompted concern for both agricultural damage and danger to human health (Department of Army, 1975). A major difference between the problem in the South and that farther north is that in the South the birds present themselves as much more accessible targets for control measures. By virtue of their tremendous concentrations they make the potential for large scale extermination very real. It is quite conceivable that a significant proportion of the entire North American populations of these birds could be eliminated if extermination efforts were maintained for several years at the major winter roosts. Before such extermination is allowed to proceed, a number of questions must be answered. These can be divided into two areas. The first area deals with whether or not the control measures are actually justified--how much agricultural damage is done by the birds and how real is their threat to human health? The second area of questioning concerns the environmental impact of both the control measures themselves as well as the effect of suddenly removing such large numbers of birds from the ecosystem. This paper presents the results of a preliminary study aimed not at answering these questions so much as providing some insight into the factors which must be considered if accurate answers are to be obtained

    The Impossibility of a Perfectly Competitive Labor Market

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    Using the institutional theory of transaction cost, I demonstrate that the assumptions of the competitive labor market model are internally contradictory and lead to the conclusion that on purely theoretical grounds a perfectly competitive labor market is a logical impossibility. By extension, the familiar diagram of wage determination by supply and demand is also a logical impossibility and the neoclassical labor demand curve is not a well-defined construct. The reason is that the perfectly competitive market model presumes zero transaction cost and with zero transaction cost all labor is hired as independent contractors, implying multi-person firms, the employment relationship, and labor market disappear. With positive transaction cost, on the other hand, employment contracts are incomplete and the labor supply curve to the firm is upward sloping, again causing the labor demand curve to be ill-defined. As a result, theory suggests that wage rates are always and everywhere an amalgam of an administered and bargained price. Working Paper 06-0

    Adam Smith’s Green Thumb and Malthus’ Three Horsemen: Cautionary tales from classical political economy

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    This essay identifies a contradiction between the flourishing interest in the environmental economics of the classical period and a lack of critical parsing of the works of its leading representatives. Its focus is the work of Adam Smith and Thomas Malthus. It offers a critical analysis of their contribution to environmental thought and surveys the work of their contemporary devotees. It scrutinizes Smith's contribution to what Karl Polanyi termed the "economistic fallacy," as well as his defenses of class hierarchy, the "growth imperative" and consumerism. It subjects to critical appraisal Malthus's enthusiasm for private property and the market system, and his opposition to market regulation. While Malthus's principal attraction to ecological economists lies in his having allegedly broadened the scope of economics, and in his narrative of scarcity, this article shows that he, in fact, narrowed the scope of the discipline and conceptualized scarcity in a reified and pseudo-scientific way

    A Consensus Definitive Classification of Scavenger Receptors and Their Roles in Health and Disease

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    Scavenger receptors constitute a large family of proteins that are structurally diverse and participate in a wide range of biological functions. These receptors are expressed predominantly by myeloid cells and recognize a diverse variety of ligands including endogenous and modified host-derived molecules and microbial pathogens. There are currently eight classes of scavenger receptors, many of which have multiple names, leading to inconsistencies and confusion in the literature. To address this problem, a workshop was organized by theUnited StatesNational Institute of Allergy and Infectious Diseases, National Institutes of Health, to help develop a clear definition of scavenger receptors and a standardized nomenclature based on that definition. Fifteen experts in the scavenger receptor field attended the workshop and, after extensive discussion, reached a consensus regarding the definition of scavenger receptors and a proposed scavenger receptor nomenclature. Scavenger receptors were defined as cell surface receptors that typically bind multiple ligands and promote the removal of nonself or altered-self targets. They often function by mechanisms that include endocytosis, phagocytosis, adhesion, and signaling that ultimately lead to the elimination of degraded or harmful substances. Based on this definition, nomenclature and classification of these receptors into 10 classes were proposed. This classification was discussed at three national meetings and input from participants at these meetings was requested. The following manuscript is a consensus statement that combines the recommendations of the initial workshop and incorporates the input received from the participants at the three national meetings

    Establishing a large prospective clinical cohort in people with head and neck cancer as a biomedical resource: head and neck 5000

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    BACKGROUND: Head and neck cancer is an important cause of ill health. Survival appears to be improving but the reasons for this are unclear. They could include evolving aetiology, modifications in care, improvements in treatment or changes in lifestyle behaviour. Observational studies are required to explore survival trends and identify outcome predictors. METHODS: We are identifying people with a new diagnosis of head and neck cancer. We obtain consent that includes agreement to collect longitudinal data, store samples and record linkage. Prior to treatment we give participants three questionnaires on health and lifestyle, quality of life and sexual history. We collect blood and saliva samples, complete a clinical data capture form and request a formalin fixed tissue sample. At four and twelve months we complete further data capture forms and send participants further quality of life questionnaires. DISCUSSION: This large clinical cohort of people with head and neck cancer brings together clinical data, patient-reported outcomes and biological samples in a single co-ordinated resource for translational and prognostic research
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