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Level Variation (level + variation)
Selected AbstractsTHE LACUSTRINE LIANGJIALOU FAN IN THE DONGYING DEPRESSION, EASTERN CHINA: DEEP-WATER RESERVOIR SANDSTONES IN A NON-MARINE RIFT BASINJOURNAL OF PETROLEUM GEOLOGY, Issue 4 2005Jin Qiang A lacustrine fan covering an area of about 175sq. km has been identified in the Liangjialou area in the SW of the Dongying Depression, a Tertiary non-marine rift basin in eastern China. Fluvial and deltaic sandstones are established reservoir rocks in the basin, and the deep-water sandstones of the fan succession, which are assigned to Member 3 of the lower Tertiary Shahejie Formation, are also thought to have important reservoir potential. Available data for this study included some 800m of core from 16 wells, well-log data from 426 wells, and 220 sq.km of 3D surveys together with well-test and other production data. From geomorphological reconstructions of the fan, we distinguish first-order (major) fan channels from second-order branched and more distal tip channels. Crevasse splays and overbank shales occur between channels, and sandstone lobes were deposited at channel mouths. Conglomeratic sandstones deposited in major channels are probably the most promising reservoir facies (average porosity c. 20%; average permeability > 1D). Fan construction took place during a single complete cycle of lake level variation which was composed of several sub-cycles. During initial highstand conditions, the fan was dominated by small-scale branched and tip channels and intervening sandy lobes. Fan size increased rapidly during the following lowstand, and then decreased during the ensuing highstand. [source] Liquid level sensor using etched silica fiberMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 4 2010J. Linesh Abstract An all optical fiber, intensity modulated sensor for discrete liquid level sensing is presented. The highly sensitive and robust design requires only silica fibers, an optical source and a detector. The sensor probe is prepared by etching the silica fibers using hydrofluoric acid. Experiments conducted with water confirm the ability of the sensor to detect liquid level variation below 10 ,m. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:883,886, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25037 [source] Assemblage level variation in springtail lower lethal temperature: the role of invasive species on sub-Antarctic Marion IslandPHYSIOLOGICAL ENTOMOLOGY, Issue 3 2009CHARLENE JANION Abstract. It is widely held both in the physiological literature, and more generally, that the average characteristics of species within an assemblage differ among sites. Such generalizations should be based on investigations of whole assemblages at sites, but this is rarely done. Here, such a study is undertaken for virtually the full assemblage of springtails found at sub-Antarctic Marion Island, by investigating supercooling points (SCPs) of 12 of the 16 species that occur there. Assemblage level variation tends to be less than that documented for assemblages across northern hemisphere sites but similar to that found at some Antarctic locations. Across this set of species, the mean SCPs of the indigenous species (mean ± SE =,17.2 ± 0.4 °C) do not differ significantly from that of the invasive species (,16.3 ± 0.7 °C). Overall, the introduction of several species to the island does not appear to have led to functional homogenization (for this trait). By combining the assemblage-level SCP data with information on the abundances of the species in each of four major habitats, it is also shown that severe but uncommon low temperature events could substantially alter species relative abundances. By resetting assemblage trajectories, such events could play an important role in the terrestrial system at the island. [source] Genetic diversity contribution to errors in short oligonucleotide microarray analysisPLANT BIOTECHNOLOGY JOURNAL, Issue 5 2006Matias Kirst Summary DNA arrays based on short oligonucleotide (, 25-mer) probes are being developed for many species, and are being applied to quantify transcript abundance variation in species with high genetic diversity. To define the parameters necessary to design short oligo arrays for maize (Zea mays L.), a species with particularly high nucleotide (single nucleotide polymorphism, SNP) and insertion-deletion (indel) polymorphism frequencies, we analysed gene expression estimates generated for four maize inbred lines using a custom Affymetrix DNA array, and identified biases associated with high levels of polymorphism between lines. Statistically significant interactions between probes and maize inbreds were detected, affecting five or more probes (out of 30 probes per transcript) in the majority of cases. SNPs and indels were identified by re-sequencing; they are the primary source of probe-by-line interactions, affecting probeset level estimates and reducing the power of detecting transcript level variation between maize inbreds. This analysis identified 36 196 probes in 5118 probesets containing markers that may be used for genotyping in natural and segregating populations for association gene analysis and genetic mapping. [source] Disparities in the Utilization of Live Donor Renal TransplantationAMERICAN JOURNAL OF TRANSPLANTATION, Issue 5 2009J. L. Gore Despite universal payer coverage with Medicare, sociodemographic disparities confound the care of patients with renal failure. We sought to determine whether adults who realize access to kidney transplantation suffer inequities in the utilization of live donor renal transplantation (LDRT). We identified adults undergoing primary renal transplantation in 2004,2006 from the United Network for Organ Sharing (UNOS). We modeled receipt of live versus deceased donor renal transplant on multilevel multivariate models that examined recipient, center and UNOS region-specific covariates. Among 41 090 adult recipients identified, 39% underwent LDRT. On multivariate analysis, older recipients (OR 0.62, 95% CI 0.56,0.68 for 50,59 year-olds vs. 18,39 year-old recipients), those of African American ethnicity (OR 0.54, 95% CI 0.50,0.59 vs. whites) and of lower socioeconomic status (OR 0.72, 95% CI 0.67,0.79 for high school-educated vs. college-educated recipients; OR 0.78, 95% CI 0.71,0.87 for lowest vs. highest income quartile) had lower odds of LDRT. These characteristics accounted for 14.2% of the variation in LDRT, more than recipient clinical variables, transplant center characteristics and UNOS region level variation. We identified significant racial and socioeconomic disparities in the utilization of LDRT. Educational initiatives and dissemination of processes that enable increased utilization of LDRT may address these disparities. [source] Approximation method for high-degree harmonics in normal mode modellingGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 1 2002R. E. M. Riva Summary For some loading applications, the normal modes approach to the viscoelastic relaxation of a spherical earth requires the use of spherical harmonics up to a high degree. Examples include postseismic deformation (internal loading) and sea level variations due to glacial isostatic adjustment (external loading). In the case of postseismic modelling, the convergence of the solution, given as a spherical harmonic expansion series, is directly dependent on loading depth and requires several thousands of terms for shallow earthquake sources. The particular structure of the analytical fundamental solutions used in normal mode techniques usually does not allow a straightforward calculation, since numerical problems can readily occur due to the stiffness of the matrices used in the propagation routines. Here we show a way of removing this stiffness problem by approximating the fundamental matrix solutions, followed by a rescaling procedure, in this way we can virtually go up to whatever harmonic degree is required. [source] Simulating the response of a closed-basin lake to recent climate changes in tropical West Africa (Lake Bosumtwi, Ghana)HYDROLOGICAL PROCESSES, Issue 13 2007Timothy M. Shanahan Abstract Historical changes in the level of Lake Bosumtwi, Ghana, have been simulated using a catchment-scale hydrological model in order to assess the importance of changes in climate and land use on lake water balance on a monthly basis for the period 1939,2004. Several commonly used models for computing evaporation in data-sparse regions are compared, including the Penman, the energy budget, and the Priestley,Taylor methods. Based on a comparison with recorded lake level variations, the model with the energy-budget evaporation model subcomponent is most effective at reproducing observed lake level variations using regional climate records. A sensitivity analysis using this model indicates that Lake Bosumtwi is highly sensitive to changes in precipitation, cloudiness and temperature. However, the model is also sensitive to changes in runoff related to vegetation, and this factor needs to be considered in simulating lake level variations. Both interannual and longer-term changes in lake level over the last 65 years appear to have been caused primarily by changes in precipitation, though the model also suggests that the drop in lake level over the last few decades has been moderated by changes in cloudiness and temperature over that time. Based on its effectiveness at simulating the magnitude and rate of lake level response to changing climate over the historical record, this model offers a potential future opportunity to examine the palaeoclimatic factors causing past lake level fluctuations preserved in the geological record at Lake Bosumtwi. Copyright © 2006 John Wiley & Sons, Ltd. [source] | ||||||||||||||||