10,581 research outputs found

    What went wrong with: "The Interaction of Neutrons With 7Be: "Lack of Standard Nuclear Physics Solution to the "Primordial 7Li Problem"", by M. Gai [arXiv:1812.09914v1]?

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    We comment here on results of the project aimed at measuring the 7Be(n,x) reactions at SARAF, Israel, in 2016, posted by M. Gai in [arXiv:1812.09914v1] without the knowledge of parts of the collaboration and against the explicit veto of the collaborators and the administration of the Paul Scherrer Institut, Switzerland. We address both the experimental shortcomings and the drawbacks in project conduction. M. Gais preprint is labeled as "on behalf of the SARAF Israel-US-Switzerland Collaboration", the author list is given as a reference to another unpublished contribution (cited as [27]) to the NPA8 conference in June 2017 in Catania). However, M. Gai did never have the right to report on unpublished proprietary data of the entire collaboration, and he was not authorized to act "on behalf of the collaboration". The contribution is declared as "accepted for publication", but in fact was retracted during the refereeing process. After several careful data evaluations, we have to state that the results of these measurements are not trustworthy and neither the given experimental data basis nor the corresponding data analysis can be improved further. Therefore, we requested to retract the posting immediately [arXiv:1904.03023]. We have to emphasize that, in our opinion, arXiv is not the appropriate platform for handling frictions in a collaboration. These problems should have been solved internally before publishing. Unfortunately, with his single-handed posting against the explicit disagreement of parts of the collaboration, M. Gai did not leave another possibility. With the present article, we expressed all our concerns and objections and we consider herewith the public discussion of this issue as closed.Comment: arXiv admin note: This version has been removed by arXiv administrators due to copyright infringemen

    Vacuum structure of a modified MIT Bag

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    An alternative to introducing and subsequently renormalizing classical parameters in the expression for the vacuum energy of the MIT bag for quarks is proposed in the massless case by appealing to the QCD trace anomaly and scale separation due to asymptotic freedom. The explicit inclusion of gluons implies an unrealistically low separation scale.Comment: 5 pages, 2 figure

    Progress Report to the TNRC for Analysis of the Economics of Atrazine Remediation for Representative Grain Farms in the Aquilla Watershed, Hill County, Texas: Subtasks 4.0-4.4

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    Four alternative BMPs for atrazine remediation were reported by Harmon and Wang for the study area. The BMPs involved alternative incorporation practices, tillage operations, and sediment ponds. Harmon and Wang reported no statistical difference in corn yields under the alternative BMPs. An economic analysis of four alternative best management practices (BMPs) for atrazine remediation in Hill County, Texas, was performed by the Agricultural and Food Policy Center (AFPC) at Texas A&M University. Using the farm-level economic simulation model FLIPSIM, AFPC scientists analyzed the financial effects of the alternative BMPs on the Texas Blackland Prairie representative farm. This farm consists of 2,000 dryland acres, divided among corn (600 acres), sorghum (750 acres), wheat (250 acres), and native pasture (150 acres). This farm also maintains a small beef cowherd. Regularly updated, the AFPC maintains more than 80 farms across the nation that form the basis for probabilistic-based agricultural policy evaluation.Agricultural and Food Policy, Resource /Energy Economics and Policy,

    Bounds on Lorentz and CPT Violation from the Earth-Ionosphere Cavity

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    Electromagnetic resonant cavities form the basis of many tests of Lorentz invariance involving photons. The effects of some forms of Lorentz violation scale with cavity size. We investigate possible signals of violations in the naturally occurring resonances formed in the Earth-ionosphere cavity. Comparison with observed resonances places the first terrestrial constraints on coefficients associated with dimension-three Lorentz-violating operators at the level of 10^{-20} GeV.Comment: 8 pages REVTe

    Calculation of the Regularized Vacuum Energy in Cavity Field Theories

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    A novel technique based on Schwinger's proper time method is applied to the Casimir problem of the M.I.T. bag model. Calculations of the regularized vacuum energies of massless scalar and Dirac spinor fields confined to a static and spherical cavity are presented in a consistent manner. While our results agree partly with previous calculations based on asymptotic methods, the main advantage of our technique is that the numerical errors are under control. Interpreting the bag constant as a vacuum expectation value, we investigate potential cancellations of boundary divergences between the canonical energy and its bag constant counterpart in the fermionic case. It is found that such cancellations do not occur.Comment: 14 pages, 4 figures, accepted for publication in Eur.Phys.J.

    Stochastic Optimization: An Application to Sub-Arctic Dairy Farming

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    The paper demonstrates how a deterministic farm linear programming (LP) model can be made stochastic and simulated using Solver and Simetar© in Excel©. The demonstration is conducted with an LP-model for a dairy farm for a sub arctic region of Norway. The income risks arising from variation in milk and crop yields due to winter damage in leys and pastures have been quantified for farms demonstrating low, medium and high forage yield risk. The estimated distribution of farm profit will be skewed to the left, indicating a downside risk. In the presence of risks, farmers maximize income by producing the milk quota with using surplus forage for meat production. The analysis demonstrated here may assist farmers and farm managers in improving sensitivity analysis for risky variables in farm LP models.dairy production, Northern Norway, stochastic optimization, stochastic simulation, yield risks, Livestock Production/Industries,

    Comparison of Risk Between Cropping Systems in Eastern Norway

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    The aim of this study was to compare production and policy risk of organic, integrated and conventional cropping systems in Norway. Experimental cropping system data (1991-1999) from eastern Norway were combined with budgeted data. Empirical distributions of total farm income for different cropping systems were estimated with a simulation model that uses a multivariate kernel density function to smooth the limited experimental data. Stochastic efficiency with respect to a function (SERF) was used to rank the cropping systems for farmers with various risk aversion levels. The results show that the organic system had the greatest net farm income variability, but the existing payment system and organic price premiums makes it the most economically viable alternative.organic, integrated and conventional crop farming, stochastic simulation, multivariate kernel estimator, risk aversion, stochastic efficiency with respect to a function, Crop Production/Industries, Risk and Uncertainty, Q12, C44,

    Analysis of long-lived radionuclides produced by proton irradiation in lead targets - γ -measurements

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    The presented work aims at a radiochemical analysis of the radionuclide inventory of a solid lead target irradiated with high energetic protons in the spallation neutron facility SINQ at Paul Scherrer Institute. Lead samples from the vicinity of the beam entry have been extracted. A detailed γ-analysis shows the radial distribution of selected radionuclides relative to the incoming beam. The concentrations of these nuclides are evaluated in dependence on the proton beam profil

    Comparison of Unix Communication Facilities Used In Linda

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    This report presents the results of an investigative effort that focuses on a first step toward providing a distributed framework for Linda system processes. In particular, we discuss the restructuring of the kernel "process" to support Tuple Space access through UNIX socket calls, rather than through shared memory primitives based on semaphore usage. A description of the restructured system and the rationale for such restructuring is presented first. Most intriguing, however, are the latter sections that discuss the ramifications and insights gained from our particular approach to system redesign, i.e., the unnecessary serialization of Tuple Space access, redundant memory copies, being victimized by the UNIX scheduler
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