319 research outputs found

    Determination of the resistivity anisotropy of SrRuO3_{3} by measuring the planar Hall effect

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    We have measured the planar Hall effect in epitaxial thin films of the itinerant ferromagnet SrRuO3 patterned with their current paths at different angles relative to the crystallographic axes. Based on the results, we have determined that SrRuO3 exhibits small resistivity anisotropy in the entire temperature range of our measurements (between 2 to 300 K); namely, both above and below its Curie temperature (~150 K). It means that in addition to anisotropy related to magnetism, the resistivity anisotropy of SrRuO3 has an intrinsic, nonmagnetic source. We have found that the two sources of anisotropy have competing effects

    The F-Landscape: Dynamically Determining the Multiverse

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    We evolve our Multiverse Blueprints to characterize our local neighborhood of the String Landscape and the Multiverse of plausible string, M- and F-theory vacua. Building upon the tripodal foundations of i) the Flipped SU(5) Grand Unified Theory (GUT), ii) extra TeV-Scale vector-like multiplets derived out of F-theory, and iii) the dynamics of No-Scale Supergravity, together dubbed No-Scale F-SU(5), we demonstrate the existence of a continuous family of solutions which might adeptly describe the dynamics of distinctive universes. This Multiverse landscape of F-SU(5) solutions, which we shall refer to as the F-Landscape, accommodates a subset of universes compatible with the presently known experimental uncertainties of our own universe. We show that by secondarily minimizing the minimum of the scalar Higgs potential of each solution within the F-Landscape, a continuous hypervolume of distinct minimum minimorum can be engineered which comprise a regional dominion of universes, with our own universe cast as the bellwether. We conjecture that an experimental signal at the LHC of the No-Scale F-SU(5) framework's applicability to our own universe might sensibly be extrapolated as corroborating evidence for the role of string, M- and F-theory as a master theory of the Multiverse, with No-Scale supergravity as a crucial and pervasive reinforcing structure.Comment: 15 Pages, 7 Figures, 1 Tabl

    Forestry on the Island of Taiwan, ROC - The State of the Art

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    The forests of Taiwan vary from lush subtropical vegetation to subalpine coniferous associations. Topography is exceedingly rugged, and stands border on the verge of silvicultural inoperability. In the 1950s and 1960s, the wood products industry in the Republic of China was of paramount importance; the production of high-quality sawtimber from old-growth cypress (Cupressaceae) stands provided the financial capital that built one of the most prosperous national economies in the modern world. In the 1980s, forestry in Taiwan is a curious blend of old methods and new technologies, as modern silvicultural practices are used to reforest cutover cypress stands, to harvest and reproduce remaining old-growth stands, and to expand the silvicultural importance of other forest types on the island. Many applied research efforts would be promising in application to the forests of Taiwan, such as long-term studies of silvicultural practices on water quality, methodology of natural regeneration applied to cypress and Taiwania cryptomerioides (Taxodiaceae), uneven-aged regulation applied to bamboo, Phyllostachys pubescens (Bambusaceae), growth and yield in coniferous plantations, effectiveness of modern herbicides in controlling competition in young plantations, and application of contemporary economic assessments in the evaluation of silvicultural alternatives

    Paramagnetic anisotropic magnetoresistance in thin films of SrRuO3

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    SrRuO3 is an itinerant ferromagnet and in its thin film form when grown on miscut SrTiO3 it has Tc of ~ 150 K and strong uniaxial anisotropy. We measured both the Hall effect and the magnetoresistance (MR) of the films as a function of the angle between the applied field and the normal to the films at temperatures above Tc. We extracted the extraordinary Hall effect that is proportional to the perpendicular component of the magnetization and thus the MR for each angle of the applied field could be correlated with the magnitude and orientation of the induced magnetization. We successfully fit the MR data with a second order magnetization expansion, which indicates large anisotropic MR in the paramagnetic state. The extremum values of resistivity are not obtained for currents parallel or perpendicular to the magnetization, probably due to the crystal symmetry.Comment: 3 pages, 3 figure

    Biting the bullet: a call for action on lead-contaminated meat in food-banks

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    Each year in the United States, food banks receive more than one million kilograms of donated hunted game meat. The National Rifle Association’s (NRA’s) Hunters for the Hungry initiative has established programs in more than 40 states for hunters to take their harvested game animal to a meat processing facility and indicate intent to donate the resulting processed and packaged meat to a local food bank. Most donated game meat is ground deer meat (venison); other donated game includes wild hog and goose. Even though the presence of ammunition-derived metallic lead fragments in donated firearms-hunted meat has been recognized for more than a decade, most of the donated hunted meat is not inspected to discard meat containing lead fragments. An underlying lack of food safety standards for adulterated donated food increases risks to low-income recipients, who are already disproportionately affected by elevated blood lead levels (BLLs).2 Primary prevention is needed for this overlooked source of lead exposure.publishedVersio

    Optimising response to an introduction of African swine fever in wild pigs

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    African swine fever virus (ASFv) is a virulent pathogen that threatens domestic swine industries globally and persists in wild boar populations in some countries. Persistence in wild boar can challenge elimination and prevent disease-free status, making it necessary to address wild swine in proactive response plans. In the United States, invasive wild pigs are abundant and found across a wide range of ecological conditions that could drive different epidemiological dynamics among populations. Information on the size of the control areas required to rapidly eliminate the ASFv in wild pigs and how this area should change with management constraints and local ecology is needed to optimize response planning. We developed a spatially explicit disease transmission model contrasting wild pig movement and contact ecology in two ecosystems in Southeastern United States. We simulated ASFv spread and determined the optimal response area (reported as the radius of a circle) for eliminating ASFv rapidly over a range of detection times (when ASFv was detected relative to the true date of introduction), culling capacities (proportion of wild pigs in the culling zone removed weekly) and wild pig densities. Large radii for response areas (14 km) were needed under most conditions but could be shortened with early detection (≤ 8 weeks) and high culling capacities (≥ 15% weekly). Under most conditions, the ASFv was eliminated in less than 22 weeks using optimal control radii, although ecological conditions with high rates of wild pig movement required higher culling capacities (≥ 10% weekly) for elimination within 1 year. The results highlight the importance of adjusting response plans based on local ecology and show that wild pig movement is a better predictor of the optimal response area than the number of ASFv cases early in the outbreak trajectory. Our framework provides a tool for determining optimal control plans in different areas, guiding expectations of response impacts, and planning resources needed for rapid elimination

    Angular dependence of domain wall resistivity in SrRuO3_{{\bf 3}} films

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    SrRuO3{\rm SrRuO_3} is a 4d itinerant ferromagnet (Tc_{c} \sim 150 K) with stripe domain structure. Using high-quality thin films of SrRuO3_{3} we study the resistivity induced by its very narrow (3\sim 3 nm) Bloch domain walls, ρDW\rho_{DW} (DWR), at temperatures between 2 K and Tc_{c} as a function of the angle, θ\theta , between the electric current and the ferromagnetic domains walls. We find that ρDW(T,θ)=sin2θρDW(T,90)+B(θ)ρDW(T,0)\rho_{DW}(T,\theta)=\sin^2\theta \rho_{DW}(T,90)+B(\theta)\rho_{DW}(T,0) which provides the first experimental indication that the angular dependence of spin accumulation contribution to DWR is sin2θ\sin^2\theta. We expect magnetic multilayers to exhibit a similar behavior.Comment: 5 pages, 5 figure

    Deriving spatially explicit direct and indirect interaction networks from animal movement data

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    Quantifying spatiotemporally explicit interactions within animal populations facilitates the understanding of social structure and its relationship with ecological processes. Data from animal tracking technologies (Global Positioning Systems [“GPS”]) can circumvent longstanding challenges in the estimation of spatiotemporally explicit interactions, but the discrete nature and coarse temporal resolution of data mean that ephemeral interactions that occur between consecutive GPS locations go undetected. Here, we developed a method to quantify individual and spatial patterns of interaction using continuous-time movement models (CTMMs) fit to GPS tracking data. We first applied CTMMs to infer the full movement trajectories at an arbitrarily fine temporal scale before estimating interactions, thus allowing inference of interactions occurring between observed GPS locations. Our framework then infers indirect interactions—individuals occurring at the same location, but at different times—while allowing the identification of indirect interactions to vary with ecological context based on CTMM outputs. We assessed the performance of our new method using simulations and illustrated its implementation by deriving disease-relevant interaction networks for two behaviorally differentiated species, wild pigs (Sus scrofa) that can host African Swine Fever and mule deer (Odocoileus hemionus) that can host chronic wasting disease. Simulations showed that interactions derived from observed GPS data can be substantially underestimated when temporal resolution of movement data exceeds 30-min intervals. Empirical application suggested that underestimation occurred in both interaction rates and their spatial distributions. CTMM-Interaction method, which can introduce uncertainties, recovered majority of true interactions. Our method leverages advances in movement ecology to quantify fine-scale spatiotemporal interactions between individuals from lower temporal resolution GPS data. It can be leveraged to infer dynamic social networks, transmission potential in disease systems, consumer–resource interactions, information sharing, and beyond. The method also sets the stage for future predictive models linking observed spatiotemporal interaction patterns to environmental drivers

    The No-Scale Multiverse at the LHC

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    We present a contemporary perspective on the String Landscape and the Multiverse of plausible string, M- and F-theory vacua, seeking to demonstrate a non-zero probability for the existence of a universe matching our own observed physics within the solution ensemble, arguing for the importance of No-Scale Supergravity as an essential common underpinning. Our context is a highly detailed phenomenological probe of No-Scale F-SU(5), a model representing the intersection of the F-lipped SU(5) X U(1)_X Grand Unified Theory (GUT) with extra TeV-Scale vector-like multiplets derived out of F-theory, and the dynamics of No-Scale Supergravity. We present a highly constrained "Golden" region with tan(beta) \sim 15, m_t = 173.0 - 174.4 GeV, M_1/2 = 455 - 481 GeV, and M_V = 691 - 1020 GeV, which simultaneously satisfies all known experimental constraints. We supplement this bottom-up phenomenological perspective with a top-down theoretical analysis of the one-loop effective Higgs potential, achieving a striking consonance via the dynamic determination of tan(beta) and M_1/2 at the local secondary minimization of the spontaneously broken electroweak Higgs vacuum V_min. We present the distinctive signatures of No-Scale F-SU(5) at the LHC, where a light stop and gluino are expected to generate a surplus of ultra-high multiplicity (>= 9) hadronic jet events. We propose modest alterations to the canonical background selection cut strategy which would enhance resolution of these events, while readily suppressing the contribution of all Standard Model processes, and allowing a clear differentiation from competing models of new physics. Detection by the LHC of the ultra-high jet signal would constitute a suggestive evocation of the intimately linked stringy origins of F-SU(5), and could provide a glimpse into the fundamental string moduli, and possibly even the workings of the No-Scale Multiverse.Comment: A review of recent work, submitted to the DICE 2010 Workshop proceedings, based on the invited talk by D.V.N. (20 Pages, 5 Tables, 18 Figures
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