3,149 research outputs found

    Primary aragonite and high-Mg calcite in the late Cambrian (Furongian) : Potential evidence from marine carbonates in Oman

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    Acknowledgements Fieldwork and sampling was funded by Petroleum Development Oman during S. Al Marjibis's Ph.D. Their help is gratefully acknowledged. We also thank colleagues at the University of Aberdeen, Julie Dougans (SUERC) for assisting with stable isotope analysis and Dr. Richard Hinton (EIMF) for assistance with ion microprobe analysis. Profs. Kiessling, Tucker, Bosence, Coleman, Dr. Dickson and an anonymous reviewer are thanked for their helpful and encouraging comments.Peer reviewedPostprin

    Got Park? Or, If you build it, they will come!

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    Grade Level(s): 9-12To provide students an opportunity to use GIS and GPS technology to evaluate, research, locate, and recommend where a new park should be located that will benefit the community

    Permeability evolution across carbonate hosted normal fault zones

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    Acknowledgements: The authors would like to thank Total E&P and BG Group for project funding and support, and the Industry Technology Facilitator for facilitating the collaborative development (grant number 3322PSD). The authors would also like to express their gratitude to the Aberdeen Formation Evaluation Society and the College of Physical Sciences at the University of Aberdeen for partial financial support. Raymi Castilla (Total E&P), Fabrizio Agosta and Cathy Hollis are also thanked for their constructive comments and suggestions to improve the standard of this manuscript as are John Still and Colin Taylor (University of Aberdeen) for technical assistance in the laboratory. Piero Gianolla is thanked for his editorial handling of the manuscript.Peer reviewedPostprin

    Temporal and Spatial Variations in Chesapeake Bay Water Quality: A Video Data Report

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    Over the past two years we have been developing computer programs to investigate various scientific visualization techniques as applied to estuarine data. The original impetus was to be able to visualize the results of the three-dimensional hydrodynamic model under development at the Virginia Institute of Marine Science, College of William and Mary (VIMS). We quickly recognized the superior ability of certain graphic approaches, especially pseudocolor animation, to efficiently transmit a tremendous amount of information to the viewer, allowing the scientist to gain an insight into the dynamics of the data not otherwise available. We decided to apply this technique to the U.S. Environmental Protection Agency (EPA) Bay Monitoring data set, a field collection effort so large that it sometimes overwhelms our traditional information presentations. What we present here is an alternative way of presenting and archiving large amounts of field measurements. The Chesapeake Bay Program began its water quality monitoring in the summer of 1984. Data collection in the mainstem of the Bay was done by University of Maryland (UMD), VIMS, and Old Dominion University (ODU), supported by EPA, while state regulatory agencies have been responsible for water quality data from the Maryland and Virginia tributaries. More than 130 stations ( 49 in the Bay proper) were occupied over 120 times each during the water years 1985 through 1990 (Figure 1). This information has been brought together to create color contoured images of the 10 different physical and water quality parameters that were measured. Each parameter for each month is summarized in a color image that shows the map-view surface and bottom distributions plus a vertical North-South section running down the natural channel from the Susquehanna to the mouth of the Bay, Each pixel in the map-view represents a lkm X lkm area. Although a certain amount of data manipulation must occur between the original logged measurements and these images, the distributions shown should best be understood as raw snapshots of what was present in the Chesapeake during that month. No data analysis or interpretation is attempted in this report

    Segmentation of Chesapeake Bay: a representative exercise

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    The goal of the CRC/RANN Waste Water Program is to provide the tools to management agencies which will enable them to make sound quantitative decisions on the siting of future sewage outfalls and the upgrading or elimination of existing sewage treatment plants. Obviously, the available funds do not permit extensive field studies at every possible outfall site. Therefore, some system is needed which will allow data to be transferred from one area to other areas within the Bay which have similar characteristics. A system of segmentation ., as suggested by Dr. D. W. Pritchard, was chosen by the Scientific Management Advisory Committee as the appropriate vehicle to achieve this transferability of the data. The following sections describe the philosophy for segmentation., the criteria to be used and two examples of the segmentation process using the Patuxent and Elizabeth River Estuaries as models

    Tectonic controls on residual oil saturation below the present-day fluid contact level in reservoirs of the Persian Gulf

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    Acknowledgments The authors would like to acknowledge, and gratefully appreciate the support of, the Aberdeen Formation Evaluation Society for their sponsorship, and Emerson (Paradigm) for providing the Geology software for the development of this study.Peer reviewedPostprin

    Report on water quality data evaluation and program design services for the James and York rivers in conjunction with the 208 planning program for the Tidewater region of Virginia

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    The study area considered in this report includes the following: The James River from Fort Monroe to the mouth of the Chickahominy River (statute mile 45) including the small tributaries on the north shore but not the Chickahominy; the York River from its mouth to the confluence of the Mattaponi and Pamunkey at West Point (statute mile 33.5) including the small tributaries along the south shore; and the small drainage area adjacent to Chesapeake Bay lying between the York and James basins. The two rivers included in this basin are Poquoson River and Back River

    Simple Optimization Method to Determine Best Management Practices to Reduce Phosphorus Loading in Echo Reservoir, Utah

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    This study develops and applies a simple linear optimization program to identify cost effective Best Management Practices (BMPs) to reduce phosphorus loading to Echo Reservoir, Utah. The optimization program tests the feasibility of proposed Total Maximum Daily Load (TMDL) allocations based on potential BMP options and provides information regarding the spatial redistribution of loads among sub-watersheds. The current version of the TMDL for Echo reservoir allocates phosphorus loads to existing non-point phosphorus sources in different sub-watersheds to meet a specified total load. Optimization results show that it is feasible to implement BMPs for non-point sources in each sub-watershed to meet reduction targets at a cost of $1.0 million. However, relaxing these targets can achieve the overall target at lower cost. The optimization program and results provide a simple tool to test the feasibility of proposed TMDL allocations based on potential BMP options and can also recommend spatial redistributions of loads among sub-watersheds to lower costs

    Late-stage disease at presentation to an HIV clinic in eastern Tanzania: A retrospective cross-sectional study

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    BackgroundĀ Late presentation and delayed treatment initiation is associated with poorĀ outcomes in patients with HIV. Little is known about the stage at whichĀ HIV patients present at HIV clinics in Tanzania.Aim:Ā This study aimed at determining the proportion of HIV patients presentingĀ with WHO clinical stages 3 and 4 disease, and the level of immunity at theĀ time of enrollment at the care and treatment center.MethodsĀ A retrospective cross-sectional study was conducted among 366 HIVinfectedĀ adults attending HIV clinic at Mwananyamala Hospital in Dar esĀ Salaam, Tanzania. Data were obtained from the care and treatment clinicĀ database.ResultsĀ Late stage disease at the time of presentation was found in 276 (75.4%)Ā of the patients; out of whom 153 (41.8%) presented with CD4 countĀ <200 cells/ul and 229 (62.6%) presented with WHO clinical stage 3 or 4Ā at the time of clinic enrollment. Strategies to improve early diagnosis andĀ treatment initiation should be improved

    Understanding complex magnetic order in disordered cobalt hydroxides through analysis of the local structure

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    In many ostensibly crystalline materials, unit-cell-based descriptions do not always capture the complete physics of the system due to disruption in long-range order. In the series of cobalt hydroxides studied here, Co(OH)2āˆ’x_{2-x}(Cl)x_x(H2_2O)n_{n}, magnetic Bragg diffraction reveals a fully compensated N\'eel state, yet the materials show significant and open magnetization loops. A detailed analysis of the local structure defines the aperiodic arrangement of cobalt coordination polyhedra. Representation of the structure as a combination of distinct polyhedral motifs explains the existence of locally uncompensated moments and provides a quantitative agreement with bulk magnetic measurements and magnetic Bragg diffraction
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