300 research outputs found

    Volunteer Glyphosate-Resistant Corn and Soybean Competition and Control

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    The continuous use of glyphosate-resistant crops has resulted in volunteer crops with the same herbicide resistance as the cash crop and an increasing weed problem. Volunteer corn reduces soybean yields however; little research has examined corn yield loss due to volunteer corn or volunteer soybean competition. These studies investigated yield loss and control of volunteer soybean in corn, and volunteer corn in soybean and corn. Using several densities of competitive plants, the yield loss was fit to a hyperbolic equation that indicated incremental yield loss (I value) to be 29.9 for volunteer corn in soybeans, 5.6 for volunteer corn in corn, and 3.2 for volunteer soybeans in corn. These data indicate that yield loss due to volunteer corn in soybean was six times greater than yield loss due to volunteer corn in corn and about ten times greater than yield loss due to volunteer soybean in corn. Reduced rates of clethodim resulted in partial control of volunteer corn in soybeans. Soybean yield loss was observed with 12.7 or 25.5 g a.i. ha-1 clethodim however, 51 g a.i. ha-1 clethodim showed minimal soybean yield loss. Glufosinate with a reduced rate of graminicide proved to be an option for excellent (\u3e90%) to good (\u3e80

    Does Online Cross-border Shopping Affect State Use Tax Liabilities?

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    How does online cross-border shopping affect state use tax liabilities? We collect our own data on actual online cross-border shopping transactions from eBay.com, focusing upon a “representative” commodity classification and a “typical” day. These data allow us to examine the extent of actual online crossborder shopping by buyers, and the subsequent potential impact on state use tax liabilities of buyers. Our results indicate that online cross-border shopping is highly prevalent on eBay, with out-of-state purchases accounting for on average 94 percent of the volume of a state’s online purchase transactions. Even so, given the limited volume of eBay-based transactions relative to total sales transactions, the likely impact of cross-border transactions on state use tax revenue streams is negligible, even if we assume full buyer compliance with state use taxes

    Reinforcement Learning-based Traffic Control: Mitigating the Adverse Impacts of Control Transitions

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    An important aspect of automated driving is to handle situations where it fails or is not allowed in specific traffic situations. This case study explores means, by which control transitions in a mixed autonomy system can be organized in order to minimize their adverse impact on traffic flow. We assess a number of different approaches for a coordinated management of transitions, covering classic traffic management paradigms and AI-driven controls. We demonstrate that they yield excellent results when compared to a do-nothing scenario. This text further details a model for control transitions that is the basis for the simulation study presented. The results encourage the deployment of reinforcement learning on the control problem for a scenario with mandatory take-over requests

    Linking geological and infrastructural requirements for large-scale underground hydrogen storage in Germany

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    Hydrogen storage might be key to the success of the hydrogen economy, and hence the energy transition in Germany. One option for cost-effective storage of large quantities of hydrogen is the geological subsurface. However, previous experience with underground hydrogen storage is restricted to salt caverns, which are limited in size and space. In contrast, pore storage facilities in aquifers -and/or depleted hydrocarbon reservoirs- could play a vital role in meeting base load needs due to their wide availability and large storage capacity, but experiences are limited to past operations with hydrogen-bearing town gas. To overcome this barrier, here we investigate hydrogen storage in porous storage systems in a two-step process: 1) First, we investigate positive and cautionary indicators for safe operations of hydrogen storage in pore storage systems. 2) Second, we estimate hydrogen storage capacities of pore storage systems in (current and decommissioned) underground natural gas storage systems and saline aquifers. Our systematic review highlights that optimal storage conditions in terms of energy content and hydrogen quality are found in sandstone reservoirs in absence of carbonate and iron bearing accessory minerals at a depth of approx. 1,100 m and a temperature of at least 40°C. Porosity and permeability of the reservoir formation should be at least 20% and 5 × 10−13 m2 (∌500 mD), respectively. In addition, the pH of the brine should fall below 6 and the salinity should exceed 100 mg/L. Based on these estimates, the total hydrogen storage capacity in underground natural gas storages is estimated to be up to 8 billion cubic meters or (0.72 Mt at STP) corresponding to 29 TWh of energy equivalent of hydrogen. Saline aquifers may offer additional storage capacities of 81.6–691.8 Mt of hydrogen, which amounts to 3.2 to 27.3 PWh of energy equivalent of hydrogen, the majority of which is located in the North German basin. Pore storage systems could therefore become a crucial element of the future German hydrogen infrastructure, especially in regions with large industrial hydrogen (storage) demand and likely hydrogen imports via pipelines and ships

    Calibration of Photomultiplier Tubes for the Fluorescence Detector of Telescope Array Experiment using a Rayleigh Scattered Laser Beam

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    We performed photometric calibration of the PhotoMultiplier Tube (PMT) and readout electronics used for the new fluorescence detectors of the Telescope Array (TA) experiment using Rayleigh scattered photons from a pulsed nitrogen laser beam. The experimental setup, measurement procedure, and results of calibration are described. The total systematic uncertainty of the calibration is estimated to be 7.2%. An additional uncertainty of 3.7% is introduced by the transport of the calibrated PMTs from the laboratory to the TA experimental site.Comment: 43 pages, 15 figure

    S3 guidelines for intensive care in cardiac surgery patients: hemodynamic monitoring and cardiocirculary system

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    Hemodynamic monitoring and adequate volume-therapy, as well as the treatment with positive inotropic drugs and vasopressors are the basic principles of the postoperative intensive care treatment of patient after cardiothoracic surgery. The goal of these S3 guidelines is to evaluate the recommendations in regard to evidence based medicine and to define therapy goals for monitoring and therapy. In context with the clinical situation the evaluation of the different hemodynamic parameters allows the development of a therapeutic concept and the definition of goal criteria to evaluate the effect of treatment

    Effect of closed minimized cardiopulmonary bypass on cerebral tissue oxygenation and microembolization

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    ObjectiveCoronary artery bypass grafting with cardiopulmonary bypass carries a risk for neurologic complications because of cerebral hypoperfusion and microembolization. The basic goals of a novel closed minimized extracorporeal circulation are to prevent excessive hemodilution and to avoid blood-air interface. The aim of this prospective randomized study was to determine the effect of using the minimized extracorporeal circulation system compared with open conventional extracorporeal circulation on cerebral tissue oxygenation and microembolization.MethodsForty patients undergoing coronary artery bypass grafting (20 in each group) were continuously monitored for changes in cerebral oxygenated hemoglobin and tissue oxygenation index by using near-infrared spectroscopy. Total microembolic count and gaseous embolic count in both median cerebral arteries were monitored with multifrequency transcranial Doppler instrumentation.ResultsIn the conventional extracorporeal circulation group there was a highly significant reduction in both cerebral oxygenated hemoglobin and tissue oxygenation index from the start to the end of cardiopulmonary bypass (P < .01). The rate of decrease in cerebral oxygenated hemoglobin after aortic cannulation was faster in the conventional extracorporeal circulation group (F test = 9.03, P < .001). No significant changes with respect to cerebral oxygenated hemoglobin or tissue oxygenation index occurred in the minimized extracorporeal circulation group, except at the beginning of rewarming (P < .01). Total embolic count, as well as gaseous embolic count, in the left and right median cerebral arteries was significantly lower in the minimized extracorporeal circulation group (all P < .05). Postoperative bleeding was greater (P < .05) and the transfusion rate was higher (P < .05) in the conventional extracorporeal circulation group.ConclusionsUse of closed minimized cardiopulmonary bypass compared with conventional open cardiopulmonary bypass preserves cerebral tissue oxygenation and reduces cerebral microembolization
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