3,483 research outputs found
A Seismic Investigation Over A Near-surface Cavern
A field experiment was conducted over a near-surface cavern with the principal objective of obtaining a spatial definition of the associated Cavity Resonance phenomenon, as reported by Watkins et. al. (1967) and by Godson and Watkins (1968). The results of the experiment were inconsistent with those of the earlier investigators in that all seismic events recorded in the vicinity of the cavity, having vertical velocity components, could be readily identified as standard modes of seismic wave transmission. A persistence of strong horizontal motion was observed for late record times. This horizontal motion was consistently oriented parallel to the cavity boundary, occurred only over an extremely limited range of the traverse at approximately a 25° polar angle to the vertical axis passing through the center of the void, and did not appear to be propagating. This energy might qualify as a cavity resonance phenomenon. © 1975
The detection and mapping of subterranean water bearing channels - phase 2
Students supported: 4 Student Assistants"The research conducted under this Grant was directed towards the development of a method for the detection and delineation of subterranean cavities. Such cavities in the carbonaceous rocks of Missouri form a vast system of interconnected channels available for the transport of ground water. These channels play an important role in the water resources of Missouri and also constitute an undesirable means of transport and dissemination of polluted waters from mining districts and heavily populated areas. Such transport systems offer little opportunity for water purification by the natural process of filtering, and such waters may be transported over considerable distances with little change in their polluted state. Prior to this Grant, a reliable method for even the detection of large cavern structures like Onondaga Cave was unknown. Past attempts at cavity detection span a broad spectrum of geophysical exploration methods. While most of these attempts have yielded some degree of success, the general consensus of the authors has been that conventional geophysical approaches to the problem do not appear adequate."--Introduction.Project # B-087-MO Agreement # 14-31-000
Horizontal cooling towers: riverine ecosystem services and the fate of thermoelectric heat in the contemporary Northeast US
The electricity sector is dependent on rivers to provide ecosystem services that help regulate excess heat, either through provision of water for evaporative cooling or by conveying, diluting and attenuating waste heat inputs. Reliance on these ecosystem services alters flow and temperature regimes, which impact fish habitat and other aquatic ecosystem services. We demonstrate the contemporary (2000–2010) dependence of the electricity sector on riverine ecosystem services and associated aquatic impacts in the Northeast US, a region with a high density of thermoelectric power plants. We quantify these dynamics using a spatially distributed hydrology and water temperature model (the framework for aquatic modeling in the Earth system), coupled with the thermoelectric power and thermal pollution model. We find that 28.4% of thermoelectric heat production is transferred to rivers, whereas 25.9% is directed to vertical cooling towers. Regionally, only 11.3% of heat transferred to rivers is dissipated to the atmosphere and the rest is delivered to coasts, in part due to the distribution of power plants within the river system. Impacts to the flow regime are minimal, while impacts to the thermal regime include increased river lengths of unsuitable habitats for fish with maximum thermal tolerances of 24.0, 29.0, and 34.0 ° C in segments downstream of plants by 0.6%, 9.8%, and 53.9%, respectively. Our analysis highlights the interactions among electricity production, cooling technologies, aquatic impacts, and ecosystem services, and can be used to assess the full costs and tradeoffs of electricity production at regional scales
A molecular biology and phase II trial of lapatinib in children with refractory CNS malignancies: a pediatric brain tumor consortium study.
High expression of ERBB2 has been reported in medulloblastoma and ependymoma; EGFR is amplified and over-expressed in brainstem glioma suggesting these proteins as potential therapeutic targets. We conducted a molecular biology (MB) and phase II study to estimate inhibition of tumor ERBB signaling and sustained responses by lapatinib in children with recurrent CNS malignancies. In the MB study, patients with recurrent medulloblastoma, ependymoma, and high-grade glioma (HGG) undergoing resection were stratified and randomized to pre-resection treatment with lapatinib 900 mg/m(2) dose bid for 7-14 days or no treatment. Western blot analysis of ERBB expression and pathway activity in fresh tumor obtained at surgery estimated ERBB receptor signaling inhibition in vivo. Drug concentration was simultaneously assessed in tumor and plasma. In the phase II study, patients, stratified by histology, received lapatinib continuously, to assess sustained response. Eight patients, on the MB trial (four medulloblastomas, four ependymomas), received a median of two courses (range 1-6+). No intratumoral target inhibition by lapatinib was noted in any patient. Tumor-to-plasma ratios of lapatinib were 10-20 %. In the 34 patients (14 MB, 10 HGG, 10 ependymoma) in the phase II study, lapatinib was well-tolerated at 900 mg/m(2) dose bid. The median number of courses in the phase II trial was two (range 1-12). Seven patients (three medulloblastoma, four ependymoma) remained on therapy for at least four courses range (4-26). Lapatinib was well-tolerated in children with recurrent or CNS malignancies, but did not inhibit target in tumor and had little single agent activity.Fil: Fouladi, Maryam. St. Jude Children’s Research Hospital; Estados UnidosFil: Stewart, Clinton F.. St. Jude Children’s Research Hospital; Estados UnidosFil: Blaney, Susan M.. Baylor College of Medicine. Texas Children’s Cancer Center; Estados UnidosFil: Onar Thomas, Arzu. St. Jude Children’s Research Hospital; Estados UnidosFil: Schaiquevich, Paula Susana. St. Jude Children’s Research Hospital; Estados Unidos. Consejo Nacional de Investigaciones CientÃficas y Técnicas; ArgentinaFil: Packer, Roger J.. Children’s National Medical Center; Estados UnidosFil: Goldman, Stewart. Anne and Robert H. Lurie Children’s Hospital of Chicago; Estados UnidosFil: Geyer, J. Rusell. Children’s Hospital and Regional Medical Center; Estados UnidosFil: Gajjar, Amar. St. Jude Children’s Research Hospital; Estados UnidosFil: Kun, Larry E.. St. Jude Children’s Research Hospital; Estados UnidosFil: Boyett, James M.. St. Jude Children’s Research Hospital; Estados UnidosFil: Gilbertson, Richard J.. St. Jude Children’s Research Hospital; Estados Unido
The Contributions of Clark P. Read on the Ecology of the Vertebrate Gut and its Parasites
Paper by George L. Stewart, Richard Lumsden, and Frank M. Fisher, Jr
Real-time simulation and control systems design by the Response Surface Methodology and designed experiments
This paper examines two cases where the fitting of a model to experimental data makes possible the solution of extremely difficult design and simulation problems. In the first (aerospace) case, designed experiments were conducted on a permanent magnet AC motor which provided the motive power for a flight surface actuator in a more electric aircraft application. The Response Surface Methodology is applied to the measured data to achieve inclusion of the component in a real-time distributed aircraft simulation. In the second (automotive) case, oscillatory acceleration responses are controlled via an electronically actuated (drive by wire) throttle. Designed experiments were conducted on the test vehicle to achieve a systematic excitation of the vehicle driveline. An approximation to the measured data is achieved by the Response Surface Methodology allowing a controller to be designed extremely rapidly
The application of inelastic neutron scattering to investigate the interaction of methyl propanoate with silica
A modern industrial route for the manufacture of methyl methacrylate involves the reaction of methyl propanoate and formaldehyde over a silica-supported Cs catalyst. Although the process has been successfully commercialised, little is known about the surface interactions responsible for the forward chemistry. This work concentrates upon the interaction of methyl propanoate over a representative silica. A combination of infrared spectroscopy, inelastic neutron scattering, DFT calculations, X-ray diffraction and temperature-programmed desorption is used to deduce how the ester interacts with the silica surface
Nitrogen dynamics in the Irish Sea and adjacent shelf waters: An exploration of dissolved organic nitrogen
AbstractRelatively little is known about dissolved organic nitrogen (DON) in the marine environment because research has historically focused on dissolved inorganic nitrogen (DIN). In this study we combine measurements of dissolved organic matter (DOM), DIN, particulate organic nitrogen (PON), dissolved inorganic phosphorus (DIP) and silicon (DIS), with temperature and salinity data from the western shelf region of the UK and Ireland, and with inorganic and organic nitrogen (N) data from the western Irish Sea to develop an understanding of N dynamics in the Irish Sea and adjacent shelf waters, and investigate the role of DON in the nitrogen budget of the seasonally stratifying western Irish Sea. In January 2013, the sampling area was divided by density fronts into 4 regions of distinct oceanography and homogeneous chemistry. DON concentrations accounted for 25.3 ± 1.8% of total dissolved N (TDN) across all regions. DOM concentrations generally decreased from the freshwater influenced water of Liverpool Bay to the oceanic waters of the Celtic Sea and Malin Shelf. Urea and dissolved free amino acids (DFAA) together made up 27.3 ± 3.1% of DON. Estimated concentrations in the rivers discharging into Liverpool Bay were 8.0 and 2.1 μmol N L−1 respectively: at the high end of reported riverine concentrations. Oceanic nutrient inputs to the Irish Sea only have a small influence on N concentrations. Riverine N inputs to the Irish Sea are substantial but are likely removed by natural N cycling processes. In the western Irish Sea, DON and PON concentrations reached maxima and minima in midsummer and early spring respectively. DIN followed the opposite trend. DON accounted for 38% of the yearly internal N cycling and we estimated that as much as 1.4 ± 1.2 μmol N L−1 of labile DON was available as an N source at the start of the spring bloom. Our study supports the view that DON plays an important role in N cycling in temperate shelf and coastal seas and should be included more often in biogeochemical measurements if we are to have a complete understanding of N dynamics in a changing world
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