2,045 research outputs found

    Jane Claire Dirks\u27s Correspondence with Stanley G. Jewett

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    This exchange between Jane Claire Dirks (later Jane Claire Dirks-Edmunds) and Stanley G. Jewett, a biologist with Region 1 of the Fish and Wildlife Service (serving Oregon and five other states), is an example of the type of correspondence Dirks had with various experts on the Pacific forest region while she was completing her doctoral thesis. Dirks-Edmunds began to study Zoology in Illinois immediately after earning her Bachelor\u27s degree in Biology from Linfield College in 1937. She returned to teach in the Biology department at Linfield from 1941-1974

    Economic and Organizational Aspects of Cooperative Feedlots

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    The cooperative organization of specialized large-scale feedlots, described in this bulletin, is not the only means open to South Dakota farmers and investors who want to enter the feeding business. A study of the cooperative feedlot was made because so little is known of its potential comparted with other forms of business organization. In no case should it be inferred that the Economics Department, South Dakota State College, is recommending that farmers and investors follow this route in all instances. Other ways of organizing a cattle feeding business include individual proprietorships with ample credit, private corporations, vertical integration, and partnerships

    Research and Consultancy Services in the Mining Industry in Zimbabwe: A Coordinated Approach Through the Mineral Resources Centre

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    IMR Report.Education in the engineering fields can be considerably enhanced if it is designed to address the immediate and long-term needs of society. In this context education not only comprises the provision of basic training, but also includes the careful planning and execution of applied and fundamental research. This paper focuses on education and research institutions that provide services to the mining sector in Zimbabwe and describes a new approach to meeting high-quality teaching, research and consultancy requirements against a background of diminishing government funding. Key units within the University of Zimbabwe providing services to the mining industry include the Institute of Mining Research, The Departments of Geology and Physics in the Faculty of Science and Mining Engineering and Metallurgy in the Faculty of Engineering. Within government, services are provided principally by the Departments of Geological Survey, Metallurgy and Mining Engineering, and the Scientific and Industrial Research and Development Centre. The major source of funding for all of these institutions is Government. There is a degree of overlap between these institutions, some of which were established more than 30 years ago with terms of reference appropriate for the time. With decreasing funding exacerbated by a harsh economic climate in Zimbabwe there is need to revisit the charters of these organizations and to review the provision of services to the mining sector. Recognition of this situation has led the Department of Geology to spearhead a new initiative to establish an alternative structure through which consultancy and research in mining related topics can be coordinated at the University of Zimbabwe. The Mineral Resources Centre (MRC) was established to facilitate fund-raising activities through consultancy services, research, postgraduate training and capital investment. By representing a group of like-minded stakeholders, the MRC can address larger projects, and thus secure more funding than individual entities will be able to obtain. The MRC is designed to be a lightweight structure that will not replace any of the existing teaching and research departments. The MRC is not be bound to any particular faculty within the university, and may even include stakeholders from outside the university. Interested parties are invited to participate on a voluntary basis in accordance with the management and quality- control guidelines laid out by the MRC. Participation is on a contract basis and will be determined for each project. Service providers that participate in the MRC agree to use their resources in the best possible way, so that services can be presented in unison. In combining forces between various departments with expertise in Earth Sciences, it is envisaged that a wider audience can be reached, a better service can be provided and a larger resource base can be tapped both within the private and the public sectors. The MRC may help coordinate capital investment, and human resource development in the various participating entities. Considering the limited availability of financial and human resources in Zimbabwe, coordination and prevention of unnecessary overlap is in itself a valuable exercise

    Lemur Biorhythms and Life History Evolution

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    Skeletal histology supports the hypothesis that primate life histories are regulated by a neuroendocrine rhythm, the Havers-Halberg Oscillation (HHO). Interestingly, subfossil lemurs are outliers in HHO scaling relationships that have been discovered for haplorhine primates and other mammals. We present new data to determine whether these species represent the general lemur or strepsirrhine condition and to inform models about neuroendocrine-mediated life history evolution. We gathered the largest sample to date of HHO data from histological sections of primate teeth (including the subfossil lemurs) to assess the relationship of these chronobiological measures with life history-related variables including body mass, brain size, age at first female reproduction, and activity level. For anthropoids, these variables show strong correlations with HHO conforming to predictions, though body mass and endocranial volume are strongly correlated with HHO periodicity in this group. However, lemurs (possibly excepting Daubentonia) do not follow this pattern and show markedly less variability in HHO periodicity and lower correlation coefficients and slopes. Moreover, body mass is uncorrelated, and brain size and activity levels are more strongly correlated with HHO periodicity in these animals. We argue that lemurs evolved this pattern due to selection for risk-averse life histories driven by the unpredictability of the environment in Madagascar. These results reinforce the idea that HHO influences life history evolution differently in response to specific ecological selection regimes

    The Lawn Hill annulus: An Ordovician meteorite impact into water-saturated dolomite

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    The Lawn Hill Impact Structure (LHIS) is located 250 km N of Mt Isa in NW Queensland, Australia, and is marked by a highly deformed dolomite annulus with an outer diameter of ~18 km, overlying low metamorphic grade siltstone, sandstone, and shale, along the NE margin of the Georgina Basin. This study provides detailed field observations from sections of the Lawn Hill annulus and adjacent areas that demonstrate a clear link between the deformation of the dolomite and the Lawn Hill impact. 40Ar-39Ar dating of impact-related melt particles provides a time of impact in the Ordovician (472 ± 8 Ma) when the Georgina Basin was an active depocenter. The timing and stratigraphic thickness of the dolomite sequence in the annulus suggest that there was possibly up to 300 m of additional sedimentary rocks on top of the currently exposed Thorntonia Limestone at the time of impact. The exposed annulus is remarkably well preserved, with preservation attributed to postimpact sedimentation. The LHIS has an atypical crater morphology with no central uplift. The heterogeneous target materials at Lawn Hill were probably low-strength, porous, and water-saturated, with all three properties affecting the crater morphology. The water-saturated nature of the carbonate unit at the time of impact is thought to have influenced the highly brecciated nature of the annulus, and restricted melt production. The impact timing raises the possibility that the Lawn Hill structure may be a member of a group of impacts resulting from an asteroid breakup that occurred in the mid-Ordovician (470 ± 6 Ma)

    Progress in Agricultural Research at the North Central Substation

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    Thousands of acres of farm land in the north central part of South Dakota have their productive future tied up with the 240 acres used for experimental research at the Substation at Eureka. Established nearly 50 years ago by the state legislature, which set aside state school lands for agricultural research, the North Central Substation is the proving ground for new agricultural methods and a living record of the accumulative effects of the old. As early as 1908, rotation experiments were started which became the first historical record in the northern plains area of the effects of cropping practices on the soil. At that time, the entire surrounding country was in wheat. There were no crop rotations, since the organic matter of the soil was good and the fertility level high. Also, there was no weed problem then. Later, the Experiment Station was to be accused of scattering weeds in one of the most interesting stories to be uncovered in the development of experimental research in this area. Foreseeing the time when the fertility of the land might become dangerously lowered by the practice of continuous cropping which was being carried on at that time, the Substation set up experimental plots. These included the basic crops of rotation-cultivated crops, small grain and legumes. In this case, the legume was sweet clover. (See more in Text

    TB26: Native Bees Associated with the Low-Bush Blueberry in Maine and Eastern Canada

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    Native bees are particularly important pollinators of lowbush blueberry. Changes in certain cultural practices since the 1930s, however, have caused substantial reductions in the native bee populations. Recent observations, however, have shown that adjustments in these practices can have a beneficial effect on native bees with accompanying increases in their numbers. Collections of native Apoidea were made in various areas of Maine and eastern Canada from 1961 through 1965 to determine the species present and their relative abundance in blueberry fields. Of the 89 species collected, 59 were taken on lowbush blueberry blossoms, and 10 in close association with lowbush blueberry. Species in the families Halictidae and Andrenidae were by far the most numerous (32 and 23 species), followed in decreasing occurrence by species in the families Bombidae, Anthophoridae, Colletidae, and Xylocopidae.https://digitalcommons.library.umaine.edu/aes_techbulletin/1165/thumbnail.jp

    Transport Through Andreev Bound States in a Graphene Quantum Dot

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    Andreev reflection-where an electron in a normal metal backscatters off a superconductor into a hole-forms the basis of low energy transport through superconducting junctions. Andreev reflection in confined regions gives rise to discrete Andreev bound states (ABS), which can carry a supercurrent and have recently been proposed as the basis of qubits [1-3]. Although signatures of Andreev reflection and bound states in conductance have been widely reported [4], it has been difficult to directly probe individual ABS. Here, we report transport measurements of sharp, gate-tunable ABS formed in a superconductor-quantum dot (QD)-normal system, which incorporates graphene. The QD exists in the graphene under the superconducting contact, due to a work-function mismatch [5, 6]. The ABS form when the discrete QD levels are proximity coupled to the superconducting contact. Due to the low density of states of graphene and the sensitivity of the QD levels to an applied gate voltage, the ABS spectra are narrow, can be tuned to zero energy via gate voltage, and show a striking pattern in transport measurements.Comment: 25 Pages, included SO
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