8,703 research outputs found

    Evaluation of TILS for use as the orbiter landing NAVAID

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    An evaluation of the tactical instrument landing systems (TILS) for use in the orbiter autoland system was made. It was found that with certain modifications, the TILS can satisfy orbiter autoland requirements. These modifications, include (1) addition of DME equipment, (2) expansion of elevation coverage from 0-10 deg to 0-30 deg, and (3) expansion to redundant systems with associated ground monitors. Additional modifications that are not necessary to meet the orbiter requirements, but that can enhance performance margin are (1) tightening of elevation antenna beam width from 1.3 deg to 0.5 deg and (2) split site configuration to provide azimuth and range coverage through rollout

    On the etale cohomology of algebraic varieties with totally degenerate reduction over p-adic fields

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    Let K be a finite extension of Q_p and X a smooth projective variety over K. We define the notion of totally degenerate reduction of such an X and the associated Chow complexes of the special fibre of a suitable regular proper model of X over the ring of integers of K. If X has such reduction, we then show that for all l, the Q_l-adic etale cohomology of X has a filtration whose graded quotients are isomorphic, as Galois modules, to the tensor product of a finite dimensional Q-vector space (with a finite unramified action of Galois) with twists of Q_l by the cyclotomic character.Comment: 29 pages This and math.AG/0601401 replace math.AG/030612

    Advanced flight deck/crew station simulator functional requirements

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    This report documents a study of flight deck/crew system research facility requirements for investigating issues involved with developing systems, and procedures for interfacing transport aircraft with air traffic control systems planned for 1985 to 2000. Crew system needs of NASA, the U.S. Air Force, and industry were investigated and reported. A matrix of these is included, as are recommended functional requirements and design criteria for simulation facilities in which to conduct this research. Methods of exploiting the commonality and similarity in facilities are identified, and plans for exploiting this in order to reduce implementation costs and allow efficient transfer of experiments from one facility to another are presented

    The Role of Environmental Payments in Sustaining Farm Incomes: A Four Year Study of Farm Businesses in an Upland Area of the UK

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    A representative sample of both participant and non-participant case study farms was examined over a three-year period in the Shropshire Hills Environmentally Sensitive Area of the UK from 1997 to 2000. The effects on farm business viability were monitored and results compared with two relevant sub samples of Farm Business Survey recorded farms. The study showed that farming profitability declined sharply over the study period but that participant case study farm profitability exceeded that of non-participants by an average of £4024 per year. This was attributable to a combination of factors which included larger average farm size, the ESA premium and more intensive farming operations. Subsidies received by both types of farms were almost totally on the "per head" basis and averaged £270 per hectare. Without these both classes of farms would have been highly unprofitable. The status of the ESA premium compared with these figures was an average of 4.5 percent of business turnover or £2358 per farm, well below that of headage based subsidies. Return on capital invested in land was consistently low, suggesting that even with these levels of subsidies the long-term future of these farms could be uncertain. The results achieved were consistent with those obtained from the Farm Business Survey data provided for the two relevant sub-samples.Farm Management,

    Gauge Field Preheating at the End of Inflation

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    Here we consider the possibility of preheating the Universe via the parametric amplification of a massless, U(1) abelian gauge field. We assume that the gauge field is coupled to the inflaton via a conformal factor with one free parameter. We present the results of high-resolution three-dimensional simulations of this model and show this mechanism efficiently preheats the Universe to a radiation-dominated final state.Comment: 8 pages, 8 figure

    Realizability of the Lorentzian (n,1)-Simplex

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    In a previous article [JHEP 1111 (2011) 072; arXiv:1108.4965] we have developed a Lorentzian version of the Quantum Regge Calculus in which the significant differences between simplices in Lorentzian signature and Euclidean signature are crucial. In this article we extend a central result used in the previous article, regarding the realizability of Lorentzian triangles, to arbitrary dimension. This technical step will be crucial for developing the Lorentzian model in the case of most physical interest: 3+1 dimensions. We first state (and derive in an appendix) the realizability conditions on the edge-lengths of a Lorentzian n-simplex in total dimension n=d+1, where d is the number of space-like dimensions. We then show that in any dimension there is a certain type of simplex which has all of its time-like edge lengths completely unconstrained by any sort of triangle inequality. This result is the d+1 dimensional analogue of the 1+1 dimensional case of the Lorentzian triangle.Comment: V1: 15 pages, 2 figures. V2: Minor clarifications added to Introduction and Discussion sections. 1 reference updated. This version accepted for publication in JHEP. V3: minor updates and clarifications, this version closely corresponds to the version published in JHE

    Labeling the New Meats: Applying Preexisting Principles to the Regulation of Radical Products

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    Over the course of the coming decade, the perception of what it means to be “meat” is going to radically change. Plant-based meat products have begun to mimic the taste and texture of meat so accurately that they are quickly becoming an acceptable alternative to traditional meat. In the near future, in vitro meat (or so-called “lab-grown” meat) will be an indistinguishable alternative to meat harvested from animals. These products promise to usher in a future of meat consumption unshackled from the animal suffering and environmental harm that are generally accepted today as a necessary evil in agriculture. With these new products will come new regulatory challenges, not least of which is the issue of how these new meat products should be labeled. This Note looks to past and present labeling regulations, as well as the theory behind labeling regulation, to argue for how the future labeling of meat substitutes should proceed. Section I of this Note introduces plant-based and in vitro meat and explores the unique aspects and implications of each. Section II examines current state and federal regulations that will affect the labeling of meat substitutes. Section III delves into the essential considerations that must be weighed when contemplating the mandatory labeling of consumer food products. Section IV looks at labeling regulations of plant-based milk and genetically engineered food products, and uses these examples as indicators for how regulation of meat substitutes should or could progress. Section V proposes specific regulatory approaches for plant-based and in vitro meat considering likely and potential future developments, and finally argues that similar standards should be applied to traditional meat
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