3,594 research outputs found

    BARLEY PRODUCTION COSTS: A CROSS-BORDER COMPARISON

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    Barley production costs are compared for five states and three Canadian provinces. A stochastic simulation, incorporating yield and exchange-rate risk, is used to characterize regional cost advantages in terms of probabilities.barley, production costs, yield risk, simulation analysis, Agricultural Finance, Production Economics,

    Longevity and Weight Loss of Free-flying Male Cecropia Moths, \u3ci\u3eHyalophora Cecropia\u3c/i\u3e (Lepidoptera: Saturniidae)

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    During their spring flight season, free-ranging male cecropia moths lived a maximum of 12 days (one of 124 recaptured moths of 387 released moths). The number of survivors declined precipitiously after day five; five to seven days is probably the usual life span. The recaptured moths did not have different initial weights than those that were not recaptured. The larger the moth the more absolute weight it lost and the faster it lost weight during the first few days. A moth lost about 20% of its weight during the first night of flight and accumulated about a 40% weight loss during the remainder of its life

    Recombining your way out of trouble: the genetic architecture of hybrid fitness under environmental stress

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    Hybridization between species is a fundamental evolutionary force that can both promote and delay adaptation. There is a deficit in our understanding of the genetic basis of hybrid fitness, especially in non-domesticated organisms. We also know little about how hybrid fitness changes as a function of environmental stress. Here, we made genetically variable F2 hybrid populations from two divergent Saccharomyces yeast species, exposed populations to ten toxins, and sequenced the most resilient hybrids on low coverage using ddRADseq. We expected to find strong negative epistasis and heterozygote advantage in the hybrid genomes. We investigated three aspects of hybridness: 1) hybridity, 2) interspecific heterozygosity, and 3) epistasis (positive or negative associations between non-homologous chromosomes). Linear mixed effect models revealed strong genotype-by-environment interactions with many chromosomes and chromosomal interactions showing species-biased content depending on the environment. Against our predictions, we found extensive selection against heterozygosity such that homozygous allelic combinations from the same species were strongly overrepresented in an otherwise hybrid genomic background. We also observed multiple cases of positive epistasis between chromosomes from opposite species, confirmed by epistasis- and selection-free simulations, which is surprising given the large divergence of the parental species (~15% genome-wide). Together, these results suggest that stress-resilient hybrid genomes can be assembled from the best features of both parents, without paying high costs of negative epistasis across large evolutionary distances. Our findings illustrate the importance of measuring genetic trait architecture in an environmental context when determining the evolutionary potential of hybrid populations

    The Iconography of Humiliation: The Depiction and Treatment of Bound Foreigners in New Kingdom Egypt

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    New Kingdom pharaohs were quick to display their dominance over foreign captives in a variety of contexts--reliefs on temple walls, statuary, various artifiacts, texts, etc.--using brutal and degrading imagery. Indeed, depictions of foreign captives in humiliating or torturous poses are ubiquitous in Egyptian iconography and reflect the celebratory nature of royal ideology. Three central questions emerge from even a cursory glance at this data. What, ultimately, was the fate of such captives? How do these scenes fit into the broader view of foreigners held by the Egyptians? Lastly, why have Egyptologists been so reluctant to study this material? Due to the simple fact that such depictions are found most often in religious contexts and make frequent use of ideology, they are often dismissed as lacking historical value. However, the ideological significance of artistic and literary presentations of foreign prisoners must given its due attention as part of the larger picture of Egyptian views towards foreigners. In many cases, historical specifics emerge even though much of the evidence is rhetorical. The following study is an analysis of bound foreigners in Egyptian iconographic and literary sources, demonstrating that depictions of bound enemies played a vital role in Egyptian ideology and that the assimilation of enemy prisoerns into New Kingdom society was essential to the empire economy. Some captives, particularly enemy leaders, were publicly executed as important components of Egyptian ritual or state ceremonies and celebrations. Furthermore, this material reveals that the Egyptians had much in common with other ancient societies in their treatment of captured enemies. It is hoped that this work spark further research and allow Egyptologists to approach these scenes and texts from a different perspective

    Torts: Oklahoma\u27s Tool for Expanding Tort Liability: \u3ci\u3eO\u27Toole v. Carlsbad Service Station\u3c/i\u3e

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    The satires of John Donne.

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    Motivations and Experiences of Teachers in a Northern Manitoba Community

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    This paper utilizes an exploratory case study method to examine the factors that attract and motivate teachers to stay in a remote, northern Canadian community. Bakan’s (1966) framework of agency and communion, provides a lens for exploring and understanding teachers’ experiences of working in the north where the term “the North” is understood not simply as one of two geographical poles, but also represents a consciousness of place. Subsequently, this study expands the conceptualization of Bakan’s notion of communion to include both the effects of emotion, which can be understood specifically as public, social, and in relation to others; as well as socio-spatial factors that illustrate the ways in which space is conceived, perceived and lived. Given the amount of human and financial capital required to recruit and retain teachers, as well as the negative implications that high levels of teacher attrition have on student success and emotional well-being, it is important to understand teachers’ perspectives on their experiences working in communities that are perceived as hard to staff.Cet article adopte une méthodologie exploratoire reposant sur l’étude de cas pour examiner les facteurs qui attirent les enseignants vers une communauté isolée du Nord canadien, et les motivent à y rester. Le cadre de l’agentivité et de la communion de Bakan (1966) offre une perspective à partir de laquelle explorer et comprendre les expériences des enseignants qui travaillent dans le nord, où l’expression « le nord » ne désigne pas uniquement un des deux pôles géographiques, mais aussi la conscience d’un lieu. Par la suite, l’étude étend la conceptualisation de la notion de communion de Bakan pour inclure les effets de l’émotion (que l’on comprend comme étant publiques, sociales et par rapport aux autres) ainsi que les facteurs socio-spatiaux qui illustrent les façons dont les lieux sont conçus, perçus et vécus. Compte tenu du capital humain et financier nécessaire pour recruter les enseignants et les maintenir en poste, ainsi que des incidences négatives qu’a le taux élevé de départ volontaire des enseignants sur le rendement et le bienêtre émotionnel des élèves, il est important de comprendre les perspectives des enseignants sur leurs expériences de travail dans des communautés perçues comme étant difficiles à pourvoir en personnel.

    Reading the Complex Skipper Butterfly Fauna of One Tropical Place

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    BACKGROUND: An intense, 30-year, ongoing biodiversity inventory of Lepidoptera, together with their food plants and parasitoids, is centered on the rearing of wild-caught caterpillars in the 120,000 terrestrial hectares of dry, rain, and cloud forest of Area de Conservacion Guanacaste (ACG) in northwestern Costa Rica. Since 2003, DNA barcoding of all species has aided their identification and discovery. We summarize the process and results for a large set of the species of two speciose subfamilies of ACG skipper butterflies (Hesperiidae) and emphasize the effectiveness of barcoding these species (which are often difficult and time-consuming to identify). METHODOLOGY/PRINCIPAL FINDINGS: Adults are DNA barcoded by the Biodiversity Institute of Ontario, Guelph, Canada; and they are identified by correlating the resulting COI barcode information with more traditional information such as food plant, facies, genitalia, microlocation within ACG, caterpillar traits, etc. This process has found about 303 morphologically defined species of eudamine and pyrgine Hesperiidae breeding in ACG (about 25% of the ACG butterfly fauna) and another 44 units indicated by distinct barcodes (n = 9,094), which may be additional species and therefore may represent as much as a 13% increase. All but the members of one complex can be identified by their DNA barcodes. CONCLUSIONS/SIGNIFICANCE: Addition of DNA barcoding to the methodology greatly improved the inventory, both through faster (hence cheaper) accurate identification of the species that are distinguishable without barcoding, as well as those that require it, and through the revelation of species "hidden" within what have long been viewed as single species. Barcoding increased the recognition of species-level specialization. It would be no more appropriate to ignore barcode data in a species inventory than it would be to ignore adult genitalia variation or caterpillar ecology
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