18,837 research outputs found

    Restoration of eucalypt grassy woodland: effects of experimental interventions on ground-layer vegetation

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    We report on the effects of broad-scale restoration treatments on the ground layer of eucalypt grassy woodland in south-eastern Australia. The experiment was conducted in two conservation reserves from which livestock grazing had previously been removed. Changes in biomass, species diversity, ground-cover attributes and life-form were analysed over a 4-year period in relation to the following experimental interventions: (1) reduced kangaroo density, (2) addition of coarse woody debris and (3) fire (a single burn). Reducing kangaroo density doubled total biomass in one reserve, but no effects on exotic biomass, species counts or ground cover attributes were observed. Coarse woody debris also promoted biomass, particularly exotic annual forbs, as well as plant diversity in one of the reserves. The single burn reduced biomass, but changed little else. Overall, we found the main driver of change to be the favourable growth seasons that had followed a period of drought. This resulted in biomass increasing by 67%, (mostly owing to the growth of perennial native grasses), whereas overall native species counts increased by 18%, and exotic species declined by 20% over the 4-year observation period. Strategic management of grazing pressure, use of fire where biomass has accumulated and placement of coarse woody debris in areas of persistent erosion will contribute to improvements in soil and vegetation condition, and gains in biodiversity, in the future.Funding and in-kind logistic support for this project was provided by the ACT Government as part of an Australian Research Council Linkage Grant (LP0561817; LP110100126). Drafts of the manuscript were read by Saul Cunningham and Ben Macdonald

    Evaluation of Structural Retrofit of a Hillside Home

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    On November 24, 2021 after months of initial planning, the project owner received approval from the San Luis Obispo Planning and Building Department for initial work on a residential remodeling submission. This approval including a grading permit and other initial site work to begin renovation of the owner’s hillside residential property

    Computer vision

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    The field of computer vision is surveyed and assessed, key research issues are identified, and possibilities for a future vision system are discussed. The problems of descriptions of two and three dimensional worlds are discussed. The representation of such features as texture, edges, curves, and corners are detailed. Recognition methods are described in which cross correlation coefficients are maximized or numerical values for a set of features are measured. Object tracking is discussed in terms of the robust matching algorithms that must be devised. Stereo vision, camera control and calibration, and the hardware and systems architecture are discussed

    Preregistration house officers in general practice: review of evidence

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    OBJECTIVES: To examine the strengths and weaknesses of the national and local schemes for preregistration house officers to spend four months in general practice, to identify any added value from such placements, and to examine the impact on career choices. DESIGN: Review of all studies that reported on placements of preregistration house officers in general practice. SETTING: 19 accounts of preregistration house officers’ experience in general practice, ranging from single case reports to a national evaluation study, in a variety of locations in Scotland and England. PARTICIPANTS: Views of 180 preregistration house officers, 45 general practitioner trainers, and 105 consultant trainers. MAIN OUTCOME MEASURES: Main findings or themes weighted according to number of studies reporting them and weighted for sample size. RESULTS: The studies were unanimous about the educational benefits of the placements. The additional learning included communication skills, social and psychological factors in illness, patient centred consultations, broadening of knowledge base, and dealing with uncertainty about diagnosis and referral. CONCLUSIONS: Despite the reported benefits and recommendations of the scheme, it is not expanding. General practitioner trainers reported additional supervision that was unremunerated. The reforms of the senior house officer grade may resolve this problem by offering the placements to senior house officers, who require less supervision

    A preliminary experiment definition for video landmark acquisition and tracking

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    Six scientific objectives/experiments were derived which consisted of agriculture/forestry/range resources, land use, geology/mineral resources, water resources, marine resources and environmental surveys. Computer calculations were then made of the spectral radiance signature of each of 25 candidate targets as seen by a satellite sensor system. An imaging system capable of recognizing, acquiring and tracking specific generic type surface features was defined. A preliminary experiment definition and design of a video Landmark Acquisition and Tracking system is given. This device will search a 10-mile swath while orbiting the earth, looking for land/water interfaces such as coastlines and rivers

    Radial glia in the proliferative ventricular zone of the embryonic and adult turtle, Trachemys scripta elegans.

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    To better understand the role of radial glial (RG) cells in the evolution of the mammalian cerebral cortex, we investigated the role of RG cells in the dorsal cortex and dorsal ventricular ridge of the turtle, Trachemys scripta elegans. Unlike mammals, the glial architecture of adult reptile consists mainly of ependymoradial glia, which share features with mammalian RG cells, and which may contribute to neurogenesis that continues throughout the lifespan of the turtle. To evaluate the morphology and proliferative capacity of ependymoradial glia (here referred to as RG cells) in the dorsal cortex of embryonic and adult turtle, we adapted the cortical electroporation technique, commonly used in rodents, to the turtle telencephalon. Here, we demonstrate the morphological and functional characteristics of RG cells in the developing turtle dorsal cortex. We show that cell division occurs both at the ventricle and away from the ventricle, that RG cells undergo division at the ventricle during neurogenic stages of development, and that mitotic Tbr2+ precursor cells, a hallmark of the mammalian SVZ, are present in the turtle cortex. In the adult turtle, we show that RG cells encompass a morphologically heterogeneous population, particularly in the subpallium where proliferation is most prevalent. One RG subtype is similar to RG cells in the developing mammalian cortex, while 2 other RG subtypes appear to be distinct from those seen in mammal. We propose that the different subtypes of RG cells in the adult turtle perform distinct functions
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