173 research outputs found

    Macroscopic Fuana of a Small Brook

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    The brief paper here presented is but the first of a series of studies which the writer proposes to work out concerning the ecological relations of the animal life of Johnson County. Johnson County has been chosen as the field for observations for several reasons, among which are its availability from Iowa City and the University buildings as a center, its wealth of diversified habitats, and the most excellent work already done by Professor Bohumil Shimek in the field of plant ecology, upon which all studies of animal ecology depend, as all animals ultimately depend upon plants for food

    The Influence of Floods upon Animals

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    The attention of the writer was first called directly to this problem by certain observations made along the White Water River, in southeastern Indiana, at the time of the great flood which swept that section of the country in the spring of 1913 —- generally known as the Dayton Flood. The writer was attempting to make collections of insects in the bottom lands of this small tributary of the Ohio river between the downpours of rain on Monday, March 24, 1913, at the time when that particular stream overflowed its banks. The observation that certain forms of animal life were destroyed outright, and others were forced to flee before the rising water, while still others were carried along on floating driftwood and other debris by which they might be introduced into new regions led to analysis of the influence of such floods upon animal life

    Terahertz imaging and spectroscopy of large-area single-layer graphene

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    We demonstrate terahertz (THz) imaging and spectroscopy of a 15x15-mm^2 single-layer graphene film on Si using broadband THz pulses. The THz images clearly map out the THz carrier dynamics of the graphene-on-Si sample, allowing us to measure sheet conductivity with sub-mm resolution without fabricating electrodes. The THz carrier dynamics are dominated by intraband transitions and the THz-induced electron motion is characterized by a flat spectral response. A theoretical analysis based on the Fresnel coefficients for a metallic thin film shows that the local sheet conductivity varies across the sample from {\sigma}s = 1.7x10^-3 to 2.4x10^-3 {\Omega}^-1 (sheet resistance, {\rho}s = 420 - 590 {\Omega}/sq).Comment: 6 pages, 5 figure

    University of California Research Seminar Network: A Prospectus

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    By webcasting the hundreds of seminars presented in the University of California system each week, UC educators hope to enhance the exchange of scientific information for their campuses and create the foundation for an international research seminar network

    Freeze-Dried Somatic Cells Direct Embryonic Development after Nuclear Transfer

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    The natural capacity of simple organisms to survive in a dehydrated state has long been exploited by man, with lyophylization the method of choice for the long term storage of bacterial and yeast cells. More recently, attempts have been made to apply this procedure to the long term storage of blood cells. However, despite significant progress, practical application in a clinical setting is still some way off. Conversely, to date there are no reports of attempts to lyophilize nucleated somatic cells for possible downstream applications. Here we demonstrate that lyophilised somatic cells stored for 3 years at room temperature are able to direct embryonic development following injection into enucleated oocytes. These remarkable results demonstrate that alternative systems for the long-term storage of cell lines are now possible, and open unprecedented opportunities in the fields of biomedicine and for conservation strategies

    Introduction to “Binary Binds”: Deconstructing Sex and Gender Dichotomies in Archaeological Practice

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    YesGender archaeology has made significant strides toward deconstructing the hegemony of binary categorizations. Challenging dichotomies such as man/woman, sex/gender, and biology/culture, approaches informed by poststructuralist, feminist, and queer theories have moved beyond essentialist and universalist identity constructs to more nuanced configurations. Despite the theoretical emphasis on context, multiplicity, and fluidity, binary starting points continue to streamline the spectrum of variability that is recognized, often reproducing normative assumptions in the evidence. The contributors to this special issue confront how sex, gender, and sexuality categories condition analytical visibility, aiming to develop approaches that respond to the complexity of theory in archaeological practice. The papers push the ontological and epistemological boundaries of bodies, personhood, and archaeological possibility, challenging a priori assumptions that contain how sex, gender, and sexuality categories are constituted and related to each other. Foregrounding intersectional approaches that engage with ambiguity, variability, and difference, this special issue seeks to “de-contain” categories, assumptions, and practices from “binding” our analytical gaze toward only certain kinds of persons and knowledges, in interpretations of the past and practices in the present
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