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Search Results: 1 - 10 of 336822 matches for " Kenneth S. Smith "
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Air quality and acute deaths in California, 2000-2012
Kenneth K. Lopiano,Richard L. Smith,S. Stanley Young
Statistics , 2015,
Abstract: Many studies have sought to determine if there is an association between air quality and acute deaths. Many consider it plausible that current levels of air quality cause acute deaths. However, several factors call causation and even association into question. Observational data sets are large and complex. Multiple testing and multiple modeling can lead to false positive findings. Publication, confirmation and other biases are also possible problems. Moreover, the fact that most data sets used in studies evaluating the relationships among air quality and public health outcomes are not publicly available makes reproducing the claims nearly impossible. Here we have built and made publicly available a dataset containing daily air quality levels, PM2.5 and ozone, daily temperature levels, minimum and maximum and daily relative humidity levels for the eight most populous California air basins. We analyzed the dataset using a moving median analysis, a standard time series analysis, and a prediction analysis within the following analysis strategy. We examine the eight air basins separately to see if estimates replicate across locations. We use leave one year out cross validation analysis to evaluate predictions. Both the moving medians analysis and the standard time series analysis found little evidence for association between air quality and acute deaths. The prediction analysis process was a run as a large factorial design using different models and holding out one year at a time. Among the variables used to predict acute death, most of the daily death variability was explained by time of year or weather variables. In summary, the empirical evidence is that current levels of air quality, ozone and PM2.5, are not causally related to acute deaths for California. An empirical and logical case can be made air quality is not causally related to acute deaths for the rest of the United States.
Determinants of Soviet Household Income
by Kenneth Smith
The European Journal of Comparative Economics , 2007,
Abstract: World Values Survey data are used to examine household income in the Soviet Union. The data, gathered Summer/Fall 1990, provide a rare opportunity to empirically examine microeconomic factors influencing a Soviet household’s position in the regional/national income distribution. The survey contains data - collected regionally - from the three Baltic republics, Belarus, and the Moscow region. The data indicate certain patterns that existed and determined Soviet household income though there are often considerable regional variations. Further, there are marked differences between income distribution determinants in the Soviet Union and the U.S. and West Germany though similarities exist as well
National estimates of emergency department visits for pediatric severe sepsis in the United States
Sara Singhal,Mathias W. Allen,John-Ryan McAnnally,Kenneth S. Smith
PeerJ , 2013, DOI: 10.7717/peerj.79
Abstract: Objective. We sought to determine the characteristics of children presenting to United States (US) Emergency Departments (ED) with severe sepsis. Study design. Cross-sectional analysis using data from the National Hospital Ambulatory Medical Care Survey (NHAMCS). Using triage vital signs and ED diagnoses (defined by the International Classification of Diseases, Ninth Revision codes), we identified children <18 years old presenting with both infection (triage fever or ICD-9 infection) and organ dysfunction (triage hypotension or ICD-9 organ dysfunction). Results. Of 28.2 million pediatric patients presenting to US EDs each year, severe sepsis was present in 95,055 (0.34%; 95% CI: 0.29–0.39%). Fever and respiratory infection were the most common indicators of an infection. Hypotension and respiratory failure were the most common indicators of organ dysfunction. Most severe sepsis occurred in children ages 31 days–1 year old (32.1%). Most visits for pediatric severe sepsis occurred during winter months (37.4%), and only 11.1% of patients arrived at the ED by ambulance. Over half of severe sepsis cases were self-pay or insured by Medicaid. A large portion (44.1%) of pediatric severe sepsis ED visits occurred in the South census region. ED length of stay was over 3 h, and 16.5% were admitted to the hospital. Conclusion. Nearly 100,000 children annually present to US EDs with severe sepsis. The findings of this study highlight the unique characteristics of children treated in the ED for severe sepsis.
关于工业部门与高等院校协作研究的若干问题
kenneth,a.smith
物理 , 1985,
Abstract: ?这类协作能给协作各方带来好处.但是我们必须从一开始就充分考虑工业资助部门和高等院校双方的利益,对此作出精心的组织.
Scattered Light Models of Protostellar Envelopes: Multiple Outflow Cavities and Misaligned Circumstellar Disks
Kenneth Wood,David Smith,Barbara Whitney,Keivan Stassun,Scott J. Kenyon,Michael J. Wolff,Karen S. Bjorkman
Physics , 2001, DOI: 10.1086/323060
Abstract: Ground based imaging, imaging polarimetry, and recent Hubble Space Telescope WFPC2 and NICMOS images of protostars have revealed very complex scattered light patterns that cannot be entirely explained by 2-D radiation transfer models. We present here for the first time radiation transfer models of T Tau and IRAS 04016+2610 that are fully 3-D, with the aim of investigating the effects on image morphology of multiple illuminating sources and infalling envelopes that have been shaped by multiple outflows. For T Tau we have constructed scattered light models where the illumination of the surrounding envelope is by a binary with each source surrounded by its own small circumstellar disk or envelope. We find that the asymmetries in the WFPC2 image of T Tau can be reproduced if the disks in the binary system are misaligned, consistent with a recently discovered bipolar outflow believed to originate from the secondary. For IRAS 04016+2610 we find that the observed scattered light pattern can be reproduced by scattering in an envelope with cavities carved by two sets of bipolar outflows, suggestive of an embedded binary system.
Corrections for the Geometric Distortion of the Tube Detectors on SANS Instruments at ORNL
Lilin He,Changwoo Do,Shuo Qian,George D. Wignall,William T. Heller,Kenneth C. Littrell,Gregory S. Smith
Physics , 2014, DOI: 10.1016/j.nima.2014.11.061
Abstract: The small-angle neutron scattering instruments at the Oak Ridge National Laboratory High Flux Isotope Reactor recently upgraded the area detectors from the large, single volume crossed-wire detectors originally installed to staggered arrays of linear position-sensitive detectors, based on the design used on the EQ-SANS instrument at ORNL Spallation Neutron Source. The specific geometry of the LPSD array requires that approaches to data reduction traditionally employed be modified. Here, two methods for correcting the geometric distortion produced by the LPSD array are presented and compared. The first method applies a correction derived from a detector sensitivity measurement performed using the same configuration as the samples are measured. In the second method presented here, a solid angle correction derived for the LPSDs is applied to data collected in any instrument configuration during the data reduction process in conjunction with a detector sensitivity measurement collected at a sufficiently long camera length where the geometric distortions are negligible. Both methods produce consistent results and yield a maximum deviation of corrected data from isotropic scattering samples of less than 0.05 for momentum transfers up to a maximum of 0.8 A-1. The results are broadly applicable to any SANS instrument employing LPSD array detectors, which will be increasingly common as instruments having higher incident flux are constructed at various neutron scattering facilities around the world.
Determination of Aquifer Properties and Groundwater Vulnerability Mapping Using Geoelectric Method in Yenagoa City and Its Environs in Bayelsa State, South South Nigeria  [PDF]
Kenneth S. Okiongbo, Edirin Akpofure
Journal of Water Resource and Protection (JWARP) , 2012, DOI: 10.4236/jwarp.2012.46040
Abstract: Nineteen Schlumberger vertical electrical soundings (VES) were carried out within and around Yenagoa city, South South Nigeria, using a maximum current electrode separation ranging between 300 - 400 m. The objectives of the study were 1) to evaluate the possibility of mapping Quaternary sediments to infer the geological structure from the electrical interpretation and identify formations that may hold fresh water with low concentration of conducting minerals such as iron 2) to evaluate the vulnerability of the aquifer in the study area. The interpretation of the data collected was by computer assisted iterative interpretation using 1-D inversion technique software (1X1D, Interpex, USA). The results of the interpretation revealed four distinct geoelectric layers. Sounding curve types obtained in the area are mostly of the form ρ1 > ρ2 < ρ3 < ρ4 (where ρ is the density) but fresh water lenses with low concentration of conducting minerals such as iron were obtained only in locations that exhibit ρ1 > ρ2 < ρ3 < ρ4 curve types. Depth to the aquifer ranges from 4.5 m in the vicinity of VES 05 to 27.0 m at the vicinity of VES 14. The resistivity of the aquiferous horizon varies between 60 - 2868 Ωm. High transverse resistance values obtained were associated with zones of high transmissivity which agrees with the geology of the Benin Formation (Coastal Plain sands) consisting of fine-medium-coarse sands. The aquifer vulnerability map illustrates the impermeability of the overburden clay layer. Values of >0.5 mhos indicate good protective capacity, while values <0.3 mhos indicate vulnerable zones with probable risk of contamination.
Geoelectric Sounding for the Determination of Aquifer Transmissivity in Parts of Bayelsa State, South South Nigeria  [PDF]
Kenneth S. Okiongbo, Ebifuro Odubo
Journal of Water Resource and Protection (JWARP) , 2012, DOI: 10.4236/jwarp.2012.46039
Abstract: The application of geophysical methods in combination with pumping tests provides a cost-effective and efficient alternative to estimate aquifer parameters. In this study, nineteen Schlumberger vertical electrical soundings (VES) were occupied in parts of Bayelsa State using a maximum current electrode separation ranging beweeen 300 - 400 m with the aim of estimating the transmissivity of the alluvial aquifer in areas where no pumping test has been carried out. Four of the soundings were carried out near existing boreholes in which pumping test had been carried out. The VES data obtained was interpreted, and layer parameters such as true resistivities and thickness were determined. The geoelectric parameters were used to generate the Dar Zarrouk parameters. Correlating the Dar Zarrouk parameter (e.g longitudinal unit conductance) with transmissivity derived from pumping test data, a constant was found which translate longitudinal unit conductance to transmissivity in a hydrogeological setting where effective porosity is the primary control on resistivity and hydraulic conductivity. Transmissivity determined from the pumping test data range between 1634.0 - 5292.0 m2/day while transmissivity values estimated from the longitudinal unit conductance (Lc) range between 721 - 8991 m2/day. The transmissivity estimated from the pumping test (Tp) data and transmissivity estimated from the longitudinal conductance (Lc) on comparison show excellent correlation (R2 = 0.92). The high transmissivity values agree with the geology of the Benin Formation (Coastal Plain sands) consisting of fine-medium-coarse sands. The results give a useful first approximation of the transmissivity and could be used to site exploratory boreholes.
Investigation of Soil Aggressiveness towards Underground Fuel Storage Tanks and Water Pipelines in Parts of Bayelsa State, Southern Nigeria  [PDF]
Kenneth S. Okiongbo, Edirin Akpofure
Engineering (ENG) , 2012, DOI: 10.4236/eng.2012.411097
Abstract: Structural failure of buried cast/ductile iron water mains and tanks due to corrosion attacks manifests in leaks and is common in most cities throughout Nigeria. The appropriate corrective action, which aims to restore pipe/tank integrity is usually based on proper understanding of the degree of corrosiveness of the soil. In an attempt to determine the potential corrosiveness of the soil to buried metallic structures in Bayelsa State, surface geoelectrical sounding was carried out. Twenty-five Schlumberger Vertical Electrical Soundings (VES) was carried out in the freshwater and meander belt geomorphic zone and the salt water mangrove swamp and estuary complex of the state using a maximum current electrode separation ranging from 200 - 400 m. The data obtained was interpreted by computer iterative modeling using a 1D inversion technique software (1X1D, Interpex, USA). The results show a high degree of heterogeneity, both laterally and vertically, which is typical of a complex depositional environment. Generally, the sub-soil condition within the expected depth of installation of water mains and storage tanks (0 - 10 m) is slightly or moderately aggressive (effective aggressivity) in the freshwater and meander belt geomorphic zone but is very strongly aggressive in the salt water mangrove swamp and estuary complex. Corrosion cells which may lead to significant corrosion failures may occur in the vicinities of strongly aggressive stations. This poses a significant corrosion risk to metallic water pipes and storage tanks. Current day design should therefore either mandate the use of a non-metallic piping product (water mains) or cathodic protection system. Prediction of potential corrosiveness of a soil and thus the application of proper corrosion control measures will not only protect the environment from spillages but will also avert cost of repair, clean-up and replacement.
Predicting Soil Corrosivity along a Pipeline Route in the Niger Delta Basin Using Geoelectrical Method: Implications for Corrosion Control  [PDF]
Kenneth S. Okiongbo, Godwin Ogobiri
Engineering (ENG) , 2013, DOI: 10.4236/eng.2013.53034
Abstract:

The corrosivity of the top three metres of the soil along a pipeline route was determined using soil electrical resistivity for the emplacement of a conduit intended to serve as a gas pipeline. Fifty-six Schlumberger vertical electrical soundings (VES) were carried using a maximum current electrode separation ranging between 24 - 100 m at 2.0 km interval. The data was interpreted using a 1D inversion technique software (1X1D, Interpex, USA). Model resistivity values were classified in terms of the degree of corrosivity. Generally, the sub-soil condition along the pipeline route is non-aggressive but being slightly or moderately aggressive in certain areas due to local conditions prevailing at the measuring stations. Based on the corrosivity along the pipeline route, appropriate cathodic protection methods are prescribed.

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