354 research outputs found

    Missouri restricted use list

    Get PDF
    "This list is to be used for informational purposes only. These restricted use pesticides have been registered with the Missouri Department of Agriculture as of Spring 1988. Pesticides are frequently added or removed from the list. There are other "restricted use" pesticides that are not listed. The products containing these pesticides were not registered in the state of Missouri as of the spring of 1988. Our latest restricted use information is available electronically over the Agricultural Economics Bullentin Board. Contact your local University Extension Office or the Pesticide Coordinator, 45 Agriculture Building, University of Missouri-Columbia, 65211, 314/882-7871, for instructions or information."--First page.James H. Jarman (Integrated Pest Management)Revised 7/88/8

    Missouri restricted use list

    Get PDF
    "This list is to be used for informational purposes only. These restricted use pesticides have been registered with the Missouri Department of Agriculture as of spring 1989. Pesticides frequently are added or removed from the list. There are other "restricted use" pesticides not listed here because the products containing those pesticides were not registered inf Missouri as of spring 1989. Our latest restricted use information is available electronically (updated periodically) over the Agricultural Electronic Bulletin Board, (314) 882-8289, Pest Management File Transfer List or Bulletins List. For further information contact your local University Extension office or Pesticide Coordinator, 45 Agriculture Building, University of Missouri-Columbia, 65211, 314/882-7871. The label on a pesticide is the last word on use and its classification as a "General'' or a "Restricted" use pesticide."--First page.James H. Jannan (Integrated Pest Management Fall, 1989)Revised 10/89/8

    Comparison of rock density determination methods used in South African platinum mines for resource planning purposes

    Get PDF
    Rock density is critical for determining the tonnage of an orebody and therefore impacts on the total resource of a deposit. Density is defined as the concentration of matter, and is expressed as mass per unit volume (g/cc; g/cm3 or t/m3). The density that is calculated will depend on the nature of the rock, and whether the volume calculated includes the open and/or closed pore volume of the rock. The pore volume will depend on the rock’s internal and external characteristics. This study looks at two methods commonly used to determine the rock density of samples taken from boreholes drilled for platinum mines on the North Eastern limb of the Bushveld Complex, South Africa. The first method is a gas pycnometer, which is almost exclusively used by laboratories. A Grabner Minidens air gas pycnometer was used. The second method is a hydrostatic immersion method, using water as the Archimedean fluid. An adapted Snowrex NH – 3 scale that can weigh a rock sample in air and in water was used. The first part of the study investigates the possible differences between conducting rock density measurements on finely milled core in the Grabner Minidens air gas pycnometer or on solid halved core samples using a hydrostatic immersion method, and the implications thereof. The second part of the study, not only investigates the differences between conducting density measurements on solid core samples or on milled core samples, but also looks at how the type of method used and how location affects the density measurement obtained. The location is important because changes in temperature and atmospheric pressure have been shown to produce small, but measurable changes in density. The density of pure water at 4 °C is approximately 1 g/cm3, increases or decreases in temperature will marginally decrease the density of water. The density of pure water at room temperature (21 °C) is 0.998 g/cm 3. Changes in atmospheric pressure have been shown to have a negligible effect on the density of most solids. The diamond drill core samples were taken from boreholes targeting the platinum group element (PGE) rich Merensky reef (MR) and Upper Group 2 (UG2) chromitite layer of the Upper Critical Zone. Samples were taken from the hangingwall (HW), reef and footwall (FW) of the MR and UG2. These rocks are made up of closely interlocking minerals, typical of cumulates. There are generally no visible pore spaces apart from highly fractured and altered samples. In part one of the study, 18,430 samples were used. The halved core samples were first measured using the hydrostatic immersion method at the exploration offices close to where the boreholes were drilled, referred to as the “Driekop” method. The samples were then sent to a laboratory in Johannesburg. Each sample was first milled to a fine powder (40 ÎŒm), and then a small portion of the milled sample (4 cm3) measured using the Grabner Minidens air gas pycnometer, referred to as the “Grabner Milled” method. For quality control, 811 of the remaining halved core samples were re-measured using the hydrostatic immersion method.The Grabner Milled results were found to be consistently higher than the Driekop results, with a mean average relative difference (AVRD) of approximately 5 % for all stratigraphic units. The difference observed can be accounted for, from the way in which the sample is prepared and the type of density that is measured. The Driekop method calculates the bulk density of the solid halved core sample, which includes all the open and closed pores of the rock. The Grabner Milled method calculates the true density of the finely milled sample, which through comminution, has excluded all open and closed pores that were in the rock. The quality control repeat measurements on the remaining halved core samples showed a good correlation with the original measurements, with a mean AVRD of only 0.33 %. In part two of the study, 82 randomly selected samples were used. The density of each solid sample was first determined using the hydrostatic immersion method. The same hydrostatic immersion method used in part one was applied at the same location; therefore it is also referred to as the “Driekop” method. The same hydrostatic method was then conducted on the samples at the laboratory in Johannesburg, referred to as “Lab water solid”. The gas pycnometer method was only conducted at the laboratory. The samples were first measured as a solid, referred to as “Grabner solid”. The samples were then milled to 40 ÎŒm and remeasured in the Grabner Minidens, referred to as “Grabner Milled”. The three solid methods results showed good correlation, with an average AVRD of only 0.01 % for the two hydrostatic immersion methods. On the other hand, there was a marked difference in results between the solid methods and the Grabner Milled method, the most significant difference being between the Grabner Milled and Grabner solid method (AVRD = 3.42 %). The resource model parameters for a project within the study area were used to illustrate the effect of density on resource planning. The average density used in the resource calculation will depend on what density method is used. The AVRD between the two methods for the mining cut density was approximately 5 %. The resource calculation showed that the difference in tonnage and 4E ounces between the two methods was also approximately 5 %. Changes in density result in equal changes in tonnage and metal content (4E ounces). Increases in dilution or overbreak from 10 to 30 cm above the optimal mining cut showed increases in tonnage and decreases in metal content. Due to similarities in rock composition between the HW, reef and FW of the MR, further dilution caused only a marginal decrease in density. The UG2 was found to be much more sensitive to dilution because of the distinct differences in rock composition between the reef, which is a chromitite layer and the HW and FW, which are both made up of plagioclase pyroxenite. Emphasis is commonly placed on the effect of dilution on grade; however this shows that the effect of density can be as important. The hydrostatic method of density determination is a very practical way of determining rock density at a remote exploration site. The whole sample can be measured and it is not restricted by the size or shape of the sample. Modern gas pycnometers have a higher degree of accuracy and precision, but need to be operated in a laboratory controlled environment, and are only capable of measuring a small amount of sample. With the correct application of quality control, both are suitable methods of density determination. The selection will depend on what type of density is required, the nature of the rock and whether the method must include or exclude pore spaces in the rock. CopyrightDissertation (MSc)--University of Pretoria, 2012.Geologyunrestricte

    A Dynamic Query-Rewriting Mechanism for Role-Based Access Control in Databases

    Get PDF
    Although Role-Based Access Control (RBAC) is a common security model currently, it has not been systematically applied in databases. In this paper, we propose a framework that enforces RBAC based on dynamic query rewriting. This framework grants privileges to data based on an intersection of roles, database structures, content, and privileges. All of this is implemented at the database level, which also offers a centralized location for administering security policies. We have implemented the framework within a healthcare setting

    Ice Patch Archaeology in Alaska: 2000–10

    Get PDF
    In the past decade, ice patch archaeological research has been initiated in several areas of Alaska, including Wrangell-St. Elias National Park and Preserve, the Amphitheater Mountains, Lake Clark National Park and Preserve, Denali National Park and Preserve, Gates of the Arctic National Park and Preserve, Chugach National Forest, and Katmai National Park. Although still in its formative stages, this research demonstrates that high-altitude ice patches have been an important part of the annual subsistence cycles of Alaskan people for at least 4000 years. Researchers have found cultural materials at 13 Alaskan ice patches. Most artifacts recovered are related to caribou hunting; however, a growing body of evidence demonstrates that ice patches were the foci for a wide range of subsistence activities, such as hunting birds, harvesting berries, and snaring small mammals. Site interpretations are based on ethnographically documented cultural practices, animal behavior, alpine ecology and geology, and archaeological analyses.Au cours de la derniĂšre dĂ©cennie, des recherches archĂ©ologiques ont Ă©tĂ© entreprises dans plusieurs nĂ©vĂ©s de l’Alaska, notamment dans les rĂ©gions suivantes : Wrangell-St. Elias National Park and Preserve, monts Amphitheater, Lake Clark National Park and Preserve, Denali National Park and Preserve, Gates of the Arctic National Park and Preserve, Chugach National Forest et Katmai National Park. Bien que ces recherches en soient toujours au stade embryonnaire, elles ont dĂ©jĂ  permis de constater que les nĂ©vĂ©s en haute altitude ont jouĂ© un rĂŽle important dans les cycles de subsistance annuels des peuples de l’Alaska pendant au moins 4 000 ans. Les chercheurs ont rĂ©cupĂ©rĂ© du matĂ©riel culturel dans 13 nĂ©vĂ©s de l’Alaska. La plupart des artefacts qui ont Ă©tĂ© trouvĂ©s se rapportent Ă  la chasse au caribou. Cependant, de plus en plus d’artefacts prouvent que les nĂ©vĂ©s Ă©taient le point de convergence d’une vaste gamme d’activitĂ©s de subsistance, comme la chasse aux oiseaux, la rĂ©colte des petits fruits et le piĂ©geage des petits mammifĂšres. L’interprĂ©tation des sites s’appuie sur les pratiques culturelles documentĂ©es de maniĂšre ethnographique, sur le comportement animal, sur l’écologie et la gĂ©ologie alpines ainsi que sur les analyses archĂ©ologiques

    My patient is short of breath: is the problem in the lung tissue?

    Get PDF
    Undifferentiated dyspnoea is a common patient presentation in the intensive care unit, medical and surgical floors, and in the emergency department. Physical examination and chest radiography are notoriously insensitive for detection and differentiation of various lung pathologies while computed tomography consumes significant resources and exposes the patient to ionizing radiation. Point-of-care ultrasound (PoCUS) is a highly sensitive and specific diagnostic tool that, with appropriate operator experience, is capable of diagnosing and differentiating between the various causes of dyspnoea. PoCUS machines are readily available, images are rapidly generated and repeatable, and technical skills are easily taught during short training sessions. Furthermore, the development of PoCUS skills in one specific area enables and enhances the development of skills in other non-related areas. This article describes the benefits, technical aspects, and challenges associated with using PoCUS to examine the lung parenchyma in the acutely dyspnoeic patient

    Integrated control of musk thistle using an introduced weevil (1993)

    Get PDF
    Reviewed October 1, 1993

    Deleting the IF1-like ζ subunit from Paracoccus denitrificans ATP synthase is not sufficient to activate ATP hydrolysis

    Get PDF
    In oxidative phosphorylation, ATP synthases interconvert two forms of free energy: they are driven by the proton motive force across an energy-transducing membrane to synthesize ATP and displace the ADP/ATP ratio from equilbrium. For thermodynamically-efficient energy conversion they must be reversible catalysts. However, in many species ATP synthases are unidirectional catalysts (their rates of ATP hydrolysis are negligible), and in others mechanisms have evolved to regulate or minimize hydrolysis. Unidirectional catalysis by Paracoccus denitrificans ATP synthase has been attributed to its unique ζ subunit, which is structurally analogous to the mammalian inhibitor protein IF1. Here, we used homologous recombination to delete the ζ subunit from the P. denitrificans genome and compared ATP synthesis and hydrolysis by the wild-type and knockout enzymes in inverted membrane vesicles and the F1-ATPase subcomplex. ATP synthesis was not affected by loss of the ζ subunit, and the rate of ATP hydrolysis increased by less than two fold, remaining negligible in comparison to the rates of the Escherichia coli and mammalian enzymes. Therefore, deleting the P. denitrificans ζ subunit is not sufficient to activate ATP hydrolysis. We close by considering our conclusions in the light of reversible catalysis and regulation in ATP synthase enzymes.This work was funded by the Medical Research Council (grant number U105663141 to J.H.)
    • 

    corecore