1,254 research outputs found

    Setting Global Standards for Sustainable Biofuels Development

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    Presented at the 180-Minute Symposium Biofuels Ablaze, organized by Susan E Cozzens, Georgia Institute of Technology, Atlanta, GA.Environmental standards are vital if the international trade in biofuels was to be allowed to begin on a massive scale. Large-scale production of biofuels in Asia ā€” such as palm oil plantations in Papua New Guinea ā€” could cause serious environmental challenges for the entire planet, starting with the clearance of forested land for plantations. Development should focus on second-hand generation biofuels are produced from the by-products of food crops, such as sugarcane, rather than crops grown purely for bio-fuel production

    Family human capital and the championing of innovation in small firms

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    This study of 94 small family firms focuses on complex interactions between individual family members and firm-level activities and outcomes. We develop and test a model of relationships between family championing of innovation, family human capital characteristics, and the firmsā€™ adoption of innovation. Family members championed many more adoptions of innovation than non-family members did, demonstrating strong family influence in smaller firms. An important point is that this strong family influence would appear insignificant without accounting for the significant moderating influence of variance in family human capital levels. This study contributes to our understanding of family influenceā€™s heterogeneous nature by modeling interaction between mediating family behaviors and moderating family characteristic

    Cloud-Trust - A Security Assessment Model for Infrastructure as a Service (IaaS) Clouds

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    The vulnerability of Cloud Computing Systems (CCSs) to Advanced Persistent Threats (APTs) is a significant concern to government and industry. We present a cloud architecture reference model that incorporates a wide range of security controls and best practices, and a cloud security assessment model ā€“ Cloud-Trust ā€“ that estimates high level security metrics to quantify the degree of confidentiality and integrity offered by a CCS or cloud service provider (CSP). Cloud-Trust is used to assess the security level of four multi-tenant IaaS cloud architectures equipped with alternative cloud security controls and to show the probability of CCS penetration (high value data compromise) is high if a minimal set of security controls are implemented. CCS penetration probability drops substantially if a cloud defense in depth security architecture is adopted that protects virtual machine (VM) images at rest, strengthens CSP and cloud tenant system administrator access controls, and which employs other network security controls to minimize cloud network surveillance and discovery of live VMs

    Mechanical Properties of non-accreting Neutron Star Crusts

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    The mechanical properties of a neutron star crust, such as breaking strain and shear modulus, have implications for the detection of gravitational waves from a neutron star as well as bursts from Soft Gamma-ray Repeaters (SGRs). These properties are calculated here for three different crustal compositions for a non-accreting neutron star that results from three different cooling histories, as well as for a pure iron crust. A simple shear is simulated using molecular dynamics to the crustal compositions by deforming the simulation box. The breaking strain and shear modulus are found to be similar in the four cases, with a breaking strain of ~0.1 and a shear modulus of ~10^{30} dyne cm^{-2} at a density of \rho = 10^{14} g cm^{-3} for simulations with an initially perfect BCC lattice. With these crustal properties and the observed properties of {PSR J2124-3358} the predicted strain amplitude of gravitational waves for a maximally deformed crust is found to be greater than the observational upper limits from LIGO. This suggests that the neutron star crust in this case may not be maximally deformed or it may not have a perfect BCC lattice structure. The implications of the calculated crustal properties of bursts from SGRs are also explored. The mechanical properties found for a perfect BCC lattice structure find that crustal events alone can not be ruled out for triggering the energy in SGR bursts.Comment: 10 pages, 6 figures, accepted for publication in Monthly Notices of the Royal Astronomical Societ

    Entanglement model of antibody viscosity

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    Antibody solutions are typically much more viscous than solutions of globular proteins at equivalent volume fraction. Here we propose that this is due to molecular entanglements that are caused by the elongated shape and intrinsic flexibility of antibody molecules. We present a simple theory in which the antibodies are modeled as linear polymers that can grow via reversible bonds between the antigen binding domains. This mechanism explains the observation that relatively subtle changes to the interparticle interaction can lead to large changes in the viscosity. The theory explains the presence of distinct power law regimes in the concentration dependence of the viscosity as well as the correlation between the viscosity and the charge on the variable domain in our anti-streptavidin IgG1 model system

    Acceptability and Feasibility of Universal Offer of Rapid Point of Care Testing for HIV in an Acute Admissions Unit: Results of the RAPID Project

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    UK guidance recommend all acute medical admissions be offered an HIV test. Our aim was to determine whether a dedicated staff member using a multimedia tool, a model found to be effective in the USA, is an acceptable, feasible, and cost-effective model when translated to a UK setting
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