528 research outputs found
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Options for Gas-to-Liquids Technology in Alaska
The purposes of this work was to assess the effect of applying new technology to the economics of a proposed natural gas-to-liquids (GTL) plant, to evaluate the potential of a slower-paced, staged deployment of GTL technology, and to evaluate the effect of GTL placement of economics. Five scenarios were economically evaluated and compared: a no-major-gas-sales scenario, a gas-pipeline/LNG scenario, a fast-paced GTL development scenario, a slow-paced GTL development scenario, and a scenario which places the GTL plant in lower Alaska, instead of on the North Slope. Evaluations were completed using an after-tax discounted cash flow analysis. Results indicate that the slow-paced GTL scenario is the only one with a rate of return greater than 10 percent. The slow-paced GTL development would allow cost saving on subsequent expansions. These assumed savings, along with the lowering of the transportation tariff, combine to distinquish this option for marketing the North Slope gas from the other scenarios. Critical variables that need further consideration include the GTL plant cost, the GTL product premium, and operating and maintenance costs
Correcting for sequence biases in present/absent calls
Correction of non-specific binding for both PM and MM probes using probe-sequence models can partially remove the probe-sequence bias in Affymetrix microarray experiments and result in better performance of the MAS 5.0 algorithm
Estimation and correction of non-specific binding in a large-scale spike-in experiment
A combined statistical analysis using the MAS5 PM-MM, GC-NSB and PDNN methods to generate probeset values from microarray data results in an improved ability to detect differential expression and estimates of false discovery rates compared with the individual methods
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Improved Water Flooding through Injection Brine Modification
Crude oil/brine/rock interactions can lead to large variations in the displacement efficiency of waterflooding, by far the most widely applied method of improved oil recovery. Laboratory waterflood tests show that injection of dilute brine can increase oil recovery. Numerous fields in the Powder River basin have been waterflooded using low salinity brine (about 500 ppm) from the Madison limestone or Fox Hills sandstone. Although many uncertainties arise in the interpretation and comparison of field production data, injection of low salinity brine appears to give higher recovery compared to brine of moderate salinity (about 7,000 ppm). Laboratory studies of the effect of brine composition on oil recovery cover a wide range of rock types and crude oils. Oil recovery increases using low salinity brine as the injection water ranged from a low of no notable increase to as much as 37.0% depending on the system being studied. Recovery increases using low salinity brine after establishing residual oil saturation (tertiary mode) ranged from no significant increase to 6.0%. Tests with two sets of reservoir cores and crude oil indicated slight improvement in recovery for low salinity brine. Crude oil type and rock type (particularly the presence and distribution of kaolinite) both play a dominant role in the effect that brine composition has on waterflood oil recovery
Precision Epoch of Reionization studies with next-generation CMB experiments
Future arcminute resolution polarization data from ground-based Cosmic
Microwave Background (CMB) observations can be used to estimate the
contribution to the temperature power spectrum from the primary anisotropies
and to uncover the signature of reionization near in the small
angular-scale temperature measurements. Our projections are based on combining
expected small-scale E-mode polarization measurements from Advanced ACTPol in
the range with simulated temperature data from the full Planck
mission in the low and intermediate region, . We show that
the six basic cosmological parameters determined from this combination of data
will predict the underlying primordial temperature spectrum at high multipoles
to better than accuracy. Assuming an efficient cleaning from
multi-frequency channels of most foregrounds in the temperature data, we
investigate the sensitivity to the only residual secondary component, the
kinematic Sunyaev-Zel'dovich (kSZ) term. The CMB polarization is used to break
degeneracies between primordial and secondary terms present in temperature and,
in effect, to remove from the temperature data all but the residual kSZ term.
We estimate a detection of the diffuse homogeneous kSZ signal from
expected AdvACT temperature data at , leading to a measurement of
the amplitude of matter density fluctuations, , at precision.
Alternatively, by exploring the reionization signal encoded in the patchy kSZ
measurements, we bound the time and duration of the reionization with
and . We find that
these constraints degrade rapidly with large beam sizes, which highlights the
importance of arcminute-scale resolution for future CMB surveys.Comment: 10 pages, 10 figure
A Dystrophin Exon-52 Deleted Miniature Pig Model of Duchenne Muscular Dystrophy and Evaluation of Exon Skipping
Duchenne muscular dystrophy (DMD) is a lethal X-linked recessive disorder caused by mutations in the DMD gene and the subsequent lack of dystrophin protein. Recently, phosphorodiamidate morpholino oligomer (PMO)-antisense oligonucleotides (ASOs) targeting exon 51 or 53 to reestablish the DMD reading frame have received regulatory approval as commercially available drugs. However, their applicability and efficacy remain limited to particular patients. Large animal models and exon skipping evaluation are essential to facilitate ASO development together with a deeper understanding of dystrophinopathies. Using recombinant adeno-associated virus-mediated gene targeting and somatic cell nuclear transfer, we generated a Yucatan miniature pig model of DMD with an exon 52 deletion mutation equivalent to one of the most common mutations seen in patients. Exon 52-deleted mRNA expression and dystrophin deficiency were confirmed in the skeletal and cardiac muscles of DMD pigs. Accordingly, dystrophin-associated proteins failed to be recruited to the sarcolemma. The DMD pigs manifested early disease onset with severe bodywide skeletal muscle degeneration and with poor growth accompanied by a physical abnormality, but with no obvious cardiac phenotype. We also demonstrated that in primary DMD pig skeletal muscle cells, the genetically engineered exon-52 deleted pig DMD gene enables the evaluation of exon 51 or 53 skipping with PMO and its advanced technology, peptide-conjugated PMO. The results show that the DMD pigs developed here can be an appropriate large animal model for evaluating in vivo exon skipping efficacy
Evolutionary conservation of regulated longevity assurance mechanisms
Short abstract: A multi-level cross-species comparative analysis of gene-expression changes accompanying increased longevity in mutant nematodes, fruit flies and mice with reduced insulin/IGF-1 signaling revealed candidate conserved mechanisms
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