3,128 research outputs found

    "Oxide-free" tip for scanning tunneling microscopy

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    We report a new tip for scanning tunneling microscopy and a tip repair procedure that allows one to reproducibly obtain atomic images of highly oriented pyrolytic graphite with previously inoperable tips. The tips are shown to be relatively oxide-free and highly resistant to oxidation. The tips are fabricated with graphite by two distinct methods

    Book Review: Russia: What Everyone Needs to Know by Timothy J. Colton

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    In Russia: What Everyone Needs to Know, Timothy J. Colton offers a concise yet comprehensive introduction to Russia’s current political climate. The book is refreshingly easy to read, writes April Curtis, and is rich in detailed information that will make it an excellent choice for those wanting to better understand the historical roots of Russia’s present

    Resource access and equity in Humboldt County (how social myth becomes social fact)

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    Rural areas of Northern California have gone without health and social services for decades. The shortcomings of local services have given rise to the idea that there are no services in these rural and isolated communities. Conditions and beliefs have brought up two important questions. The first question is how can access and knowledge of available services be improved in rural areas? The second question is, through what mechanisms do communities develop their facts? To address the previous questions, I worked with the primary health and social service provider in Humboldt County, CA. We developed a database of local services that anyone from computers and smart devices could access. While creating the database, we discovered that while there are services in this area, there exists a gap in organizational awareness. The majority of community-based organizations do not communicate with one another, and similarly, the residents of rural communities go unaware of available services. Issues of awareness lead me to study social learning utilizing several fundamental concepts; anthology, semantic memory, willful ignorance, akrasia Phenomenology, Myth, Pragmatism, and Semiotics

    Daytime Summer Microclimate Influence of Large Woody Debris on Dewatered Sediments in Lake Mills, WA Following Dam Removal

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    In 2014, dam removal from the Elwha River, Washington state, exposed large areas of previously submerged sediment. The Olympic National Park placed ~100 large logs on 2 ha of exposed sediment to promote plant establishment. I quantified patterns of three microclimate variables near logs: wind speed at 10-cm height (u10), sediment temperature (TS), and evaporation rate (E); and their relationships to broader environmental factors. The northern-most log, exposed to northerly winds, was measured along 3-m perpendicular transects 14 times during August and September 2015. I determined nonlinear and multilevel regressions to investigate patterns and create models of microclimate as functions of environmental factors and distance from the log. Maximum u10 decreased to the lee. Decreases near the log occurred for u10 to the north and south, and for TS and E to the shaded north. Windward and leeward u10 models include local wind speed and distance from log. Northern TS is related to solar radiation, air temperature and distance from log. Southern TS is related to air temperature. Northern E is related to solar radiation, vapor pressure deficit and distance from log. Southern E is related to solar radiation and vapor pressure deficit. Models of southern u10 and northern TS and E were validated with data from 8 wind-protected logs, but lack of validation of the other microclimate models indicate the northern-most log has unique microclimate. Species-specific physiological information is required to predict plant reactions to near-log microclimate. All models require more data to broaden their scope

    Technology towards transcendence : apocalyptic spiritualities & the genesis of science fiction in Weimar Germany

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    This thesis seeks to understand how, in the early twentieth century, esoteric schools in German-speaking Europe influenced the proto-science fiction genre, especially the cinema of Weimar Germany. It is inspired by the work of historians such as Suzanne Marchand and Corinna Treitel, but expands their focus to the period after the First World War and into new forms of mass media. It investigates how discoveries in archaeology and philology reshaped the modern European understanding of the technological prestige of ancient Eastern civilizations, as well as the longstanding presumptions about the originality behind Western religious texts and traditions. In the decade leading up to the Great War, the shock of these discoveries inspired a countercultural revival of the occult and Gnosticism, which in turn found an unexpectedly strong expression among writers of pulp fiction and sensationalist literature, especially those of the science fiction and fantasy genres. In particular, this thesis focuses on the screenwriters, directors, and other filmmakers behind Weimar science fiction films. Its conclusions are tentative, pending on further research

    Lateral Signals in Piezoresponse Force Microscopy at Domain Boundaries of Ferroelectric Crystals

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    In piezoresponse force microscopy a lateral signal at the domain boundaries is occasionally observed. In recent years, a couple of experiments have been reported and varying explanations for the origin of this lateral signal have been proposed. Additionally, elaborated theoretical modeling for this particular issue has been carried out. Here we present experimental data obtained on different crystallographic cuts of LiNbO3\rm LiNbO_3, BaTiO3\rm BaTiO_3, and KTiOPO4\rm KTiOPO_4 single crystals. We could thereby rule out some of the explanations proposed so far, introduce another possible mechanism, and quantitatively compare our results to the existing modeling

    Optimal resource allocation and prolonged dormancy strategies in herbaceous plants

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    1. Understanding the fitness consequences of different life histories is critical for explaining their diversity and for predicting effects of changing environmental conditions. However, current theory on plant life histories relies on phenomenological, rather than mechanistic, models of resource production. 2. We combined a well-supported mechanistic model of ontogenetic growth that incorporates differences in the size-dependent scaling of gross resource production and maintenance costs with a dynamic optimization model to predict schedules of reproduction and prolonged dormancy (plants staying below ground for ≥ 1 growing season) that maximize lifetime offspring production. 3. Our model makes three novel predictions: First, maintenance costs strongly influence the conditions under which a monocarpic or polycarpic life history evolves and how resources should be allocated to reproduction by polycarpic plants. Second, in contrast to previous theory, our model allows plants to compensate for low survival conditions by allocating a larger proportion of resources to storage and thereby improving overwinter survival. Incorporating this ecological mechanism in the model is critically important because without it our model never predicts significant investment into storage, which is inconsistent with empirical observations. Third, our model predicts that prolonged dormancy may evolve solely in response to resource allocation tradeoffs. 4. Significance: Our findings reveal that maintenance costs and the effects of resource allocation on survival are primary determinants of the fitness consequences of different life history strategies, yet previous theory on plant life history evolution has largely ignored these factors. Our findings also validate recent arguments that prolonged dormancy may be an optimal response to costs of sprouting. These findings have broad implications for understanding patterns of plant life history variation and predicting plant responses to changing environments
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