479 research outputs found

    Use of wire line logs for estimation of strength variability in cap-­‐rock lithologies

    Get PDF
    The characterization of cap-rock, low permeability and high capillary entry pressure lithologies is important for modeling the response of cap-rocks to increased pressures due to CO2 injection. We evaluate the use of publically available wireline log data to provide empirical estimate of rock strength in order to determine the strength of top seal over a range of scales. This method is being used to characterize cap-rock lithologies in systems proposed for CO2 geosequestration, these data will be combined with outcrop fracture density observations, petrology, lithologic stacking patterns and mineralogy to predict the potential for bypass. Analysis to date includes wells with monopole and dipole sonic logs for comparison of the relationships established empirically by other workers and used in this study to estimate the dynamic values for Poisson’s Ratio and Young’s Modulus from publically available vintage well log data in Utah. This study focuses specifically on the Jurassic Carmel Formation, which is a cap-rock to the underlying proposed CO2 injection reservoir, the Navajo Sandstone. This study compliments the well data with outcrop characterization of the Carmel Formation, which we split into 3 mechanical units based on lithologic stacking patterns, fracture density, and relationships observed between the percent shale and fracture spacing ratio. Results obtained from the well log analysis fall within the published ranges for these rock types, however the data show a variability which is being evaluated further to understand if these observations are related to geology or artifacts associated with the wireline data. In future the use of these empirical estimates will provide a lower estimate for subsurface rock strength, as well as provide a means to closely tie outcrop observations to those made from subsurface data

    Fracture behavior across interfaces in seal lithologies

    Get PDF
    Faults and fracture networks at depth are important fluid pathways, especially in fine-grained, low permeability seal lithologies. Discontinues in sealing lithologies can create seal bypass systems, leading to the failure of CO2 geosequestration sites or hydrocarbon traps. We characterize the occurrence of and changes in discontinuity patterns and the associated changes in elastic moduli across sedimentologic interfaces to document the importance of these discontinuities for fluid management in the subsurface and potential for re-activation in high-pressure injection scenarios. We evaluate well-exposed, fine-grained, low-permeability Mesozoic and Paleozoic units that are seals of potential CO2 repositories on the Colorado Plateau and show evidence for open fractures and fluid flow in the subsurface. Field observations document changes in fracture distributions across lithologic boundaries allowing us to identify mechano-stratigraphic units and focus on the effect of lithologic interfaces on fracture distribution. An interface marks the boundary between facies in a seal and in this study the fractures are shown to deflect or arrest at the interface. In outcrop fracture intensity varies in from 1 to 18 fractures per meter and fracture apertures range from mm to cm. The mineralized fractures often have associated alteration halos along their boundaries; their general orientation follows that of discontinuities within the underlying reservoir facies or adjacent faults. The recognition of these changes in fracture distribution is important for forward modeling of fluid flow and risk management. Studying the occurrence of and changes in fracture patterns from outcrops and scaling it up for use in modeling at a field scale is difficult due to the lack of direct correlation between outcrop observations and subsurface data. Due to the size and amount of data needed to model fluid flow at the field scale the meso-scale (cm to m) variability of rock properties is often neglected. We evaluate this meso-scale variability in elastic moduli, where possible. We combine mechano-stratigraphic outcrop observations with elastic moduli calculated from publically available wire line log data to evaluate the variability in rock strength within the heterolithic top seal. Relationships between changes in Young’s modulus to resulting fracture distribution can then be observed. The outcome of this analysis can be used for modeling the effectiveness of seal for storage of CO2 in the underlying reservoirs. Digitized publically available wire line well log data were used to calculate Poisson’s ratio and Young’s modulus over the Carmel Formation and upper most 3 m of the underlying Navajo Sandstone. Our calculations show that Young’s Modulus can range between 15 to 34 GPa across 60 cm of the intra-seal interfaces, and an average difference of 5 GPa across the reservoir seal interface. These variations will affect fracture distributions and fluid behavior in the subsurface. These data provide a means to closely tie outcrop observations to derived estimates of subsurface rock strength. The characterization of rock strength variability is especially important for modeling the response of seals to increased pressure, due to CO2 injection, and will allow for better site screening and fluid management once injection projects are underway

    Accurate Fundamental Parameters or A, F, and G-type Supergiants in the Solar Neighbourhood

    Full text link
    The following parameters are determined for 63 Galactic supergiants in the solar neighbourhood: effective temperature Teff, surface gravity log g, iron abundance log e(Fe), microturbulent parameter Vt, mass M/Msun, age t and distance d. A significant improvement in the accuracy of the determination of log g and, all parameters dependent on it, is obtained through application of van Leeuwens (2007) re-reduction of the Hipparcos parallaxes. The typical error in the log g values is now +-0.06 dex for supergiants with distances d < 300 pc and +-0.12 dex for supergiants with d between 300 and 700 pc; the mean error in Teff for these stars is +-120 K. For supergiants with d > 700 pc parallaxes are uncertain or unmeasurable, so typical errors in their log g values are 0.2-0.3 dex. A new Teff scale for A5-G5 stars of luminosity classes Ib-II is presented. Spectral subtypes and luminosity classes of several stars are corrected. Combining the Teff and log g with evolutionary tracks, stellar masses and ages are determined; a majority of the sample has masses between 4 Msun and 15 Msun and, hence, their progenitors were early to middle B-type main sequence stars. Using Fe ii lines, which are insensitive to departures from LTE, the microturbulent parameter Vt and the iron abundance log e(Fe) are determined from high-resolution spectra. The parameter Vt is correlated with gravity: Vt increases with decreasing log g. The mean iron abundance for the 48 supergiants with distances d < 700 pc is log e(Fe)=7.48+-0.09, a value close to the solar value of 7.45+-0.05, and thus the local supergiants and the Sun have the same metallicity.Comment: 12 pages, 9 figures. Will be published at MNRA

    Drug-gene interactions of antihypertensive medications and risk of incident cardiovascular disease: a pharmacogenomics study from the CHARGE consortium

    Get PDF
    Background Hypertension is a major risk factor for a spectrum of cardiovascular diseases (CVD), including myocardial infarction, sudden death, and stroke. In the US, over 65 million people have high blood pressure and a large proportion of these individuals are prescribed antihypertensive medications. Although large long-term clinical trials conducted in the last several decades have identified a number of effective antihypertensive treatments that reduce the risk of future clinical complications, responses to therapy and protection from cardiovascular events vary among individuals. Methods Using a genome-wide association study among 21,267 participants with pharmaceutically treated hypertension, we explored the hypothesis that genetic variants might influence or modify the effectiveness of common antihypertensive therapies on the risk of major cardiovascular outcomes. The classes of drug treatments included angiotensin-converting enzyme inhibitors, beta-blockers, calcium channel blockers, and diuretics. In the setting of the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) consortium, each study performed array-based genome-wide genotyping, imputed to HapMap Phase II reference panels, and used additive genetic models in proportional hazards or logistic regression models to evaluate drug-gene interactions for each of four therapeutic drug classes. We used meta-analysis to combine study-specific interaction estimates for approximately 2 million single nucleotide polymorphisms (SNPs) in a discovery analysis among 15,375 European Ancestry participants (3,527 CVD cases) with targeted follow-up in a case-only study of 1,751 European Ancestry GenHAT participants as well as among 4,141 African-Americans (1,267 CVD cases). Results Although drug-SNP interactions were biologically plausible, exposures and outcomes were well measured, and power was sufficient to detect modest interactions, we did not identify any statistically significant interactions from the four antihypertensive therapy meta-analyses (Pinteraction &gt; 5.0×10−8). Similarly, findings were null for meta-analyses restricted to 66 SNPs with significant main effects on coronary artery disease or blood pressure from large published genome-wide association studies (Pinteraction ≄ 0.01). Our results suggest that there are no major pharmacogenetic influences of common SNPs on the relationship between blood pressure medications and the risk of incident CVD

    Genetic association study of QT interval highlights role for calcium signaling pathways in myocardial repolarization.

    Get PDF
    The QT interval, an electrocardiographic measure reflecting myocardial repolarization, is a heritable trait. QT prolongation is a risk factor for ventricular arrhythmias and sudden cardiac death (SCD) and could indicate the presence of the potentially lethal mendelian long-QT syndrome (LQTS). Using a genome-wide association and replication study in up to 100,000 individuals, we identified 35 common variant loci associated with QT interval that collectively explain ∌8-10% of QT-interval variation and highlight the importance of calcium regulation in myocardial repolarization. Rare variant analysis of 6 new QT interval-associated loci in 298 unrelated probands with LQTS identified coding variants not found in controls but of uncertain causality and therefore requiring validation. Several newly identified loci encode proteins that physically interact with other recognized repolarization proteins. Our integration of common variant association, expression and orthogonal protein-protein interaction screens provides new insights into cardiac electrophysiology and identifies new candidate genes for ventricular arrhythmias, LQTS and SCD

    GWAS of longevity in CHARGE consortium confirms APOE and FOXO3 candidacy.

    Get PDF
    To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked Files. This article is open access.The genetic contribution to longevity in humans has been estimated to range from 15% to 25%. Only two genes, APOE and FOXO3, have shown association with longevity in multiple independent studies.We conducted a meta-analysis of genome-wide association studies including 6,036 longevity cases, age ≄90 years, and 3,757 controls that died between ages 55 and 80 years. We additionally attempted to replicate earlier identified single nucleotide polymorphism (SNP) associations with longevity.In our meta-analysis, we found suggestive evidence for the association of SNPs near CADM2 (odds ratio [OR] = 0.81; p value = 9.66 × 10(-7)) and GRIK2 (odds ratio = 1.24; p value = 5.09 × 10(-8)) with longevity. When attempting to replicate findings earlier identified in genome-wide association studies, only the APOE locus consistently replicated. In an additional look-up of the candidate gene FOXO3, we found that an earlier identified variant shows a highly significant association with longevity when including published data with our meta-analysis (odds ratio = 1.17; p value = 1.85×10(-10)).We did not identify new genome-wide significant associations with longevity and did not replicate earlier findings except for APOE and FOXO3. Our inability to find new associations with survival to ages ≄90 years because longevity represents multiple complex traits with heterogeneous genetic underpinnings, or alternatively, that longevity may be regulated by rare variants that are not captured by standard genome-wide genotyping and imputation of common variants.Netherlands Organisation of Scientific Research NWO Investments 175.010.2005.011 911-03-012 Research Institute for Diseases in the Elderly 014-93-015 RIDE2 Netherlands Genomics Initiative (NGI)/Netherlands Organisation for Scientific Research (NWO) 050-060-810 Erasmus Medical Center Erasmus University, Rotterdam Netherlands Organization for the Health Research and Development (ZonMw) Research Institute for Diseases in the Elderly (RIDE) Ministry of Education, Culture and Science Ministry for Health, Welfare and Sports European Commission (DG XII) Municipality of Rotterdam National Institutes of Health National Institute on Aging (NIA) R01 AG005407 R01 AR35582 R01 AR35583 R01 AR35584 R01 AG005394 R01 AG027574 R01 AG027576 AG023629 R01AG29451 U01AG009740 RC2 AG036495 RC4 AG039029 P30AG10161 R01AG17917 R01AG15819 R01AG30146 U01-AG023755 U19-AG023122 NHLBI HHSN 268201200036C HHSN268200800007C N01HC55222 N01HC85079 N01HC85080 N01HC85081 N01HC85082 N01HC85083 N01HC 85086 HL080295 HL087652 HL105756 National Institute of Neurological Disorders and Stroke (NINDS) National Center for Advancing Translational Sciences, CTSI UL1TR000124 National Institute of Diabetes and Digestive and Kidney Disease Diabetes Research Center (DRC) DK063491 National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) National Center for Research Resources (NCRR) NIH Roadmap for Medical Research U01 AR45580 U01 AR45614 U01 AR45632 U01 AR45647 U01 AR45654 U01 AR45583 U01 AG18197 U01-AG027810 UL1 RR024140 NIAMS R01-AR051124 RC2ARO58973 National Heart, Lung and Blood Institute's Framingham Heart Study N01-HC-25195 Affymetrix, Inc N02-HL-6-4278 Robert Dawson Evans Endowment of the Department of Medicine at Boston University School of Medicine Boston Medical Center National Institute of Arthritis, Musculoskeletal and Skin Diseases NIA R01 AR/AG 41398 NIH N01-AG-12100 NIA Intramural Research Program Hjartavernd (the Icelandic Heart Association) Althingi (the Icelandic Parliament) Illinois Department of Public Health Translational Genomics Research Institute Italian Ministry of Health ICS110.1/RF97.71 U.S. National Institute on Aging 263 MD 9164 263 MD 821336 Intramural Research Program of the NIH, National Institute on Aging 1R01AG028321 1R01HL09257

    Children’s Moral Emotion Attribution in the Happy Victimizer Task: The Role of Response Format

    Get PDF
    Previous research in the happy victimizer tradition indicated that preschool and early elementary-school children attribute positive emotions to the violator of a moral norm, whereas older children attribute negative moral emotions. Cognitive and motivational processes have been suggested as underlying this developmental shift. The current research investigated whether making the happy victimizer task less cognitively demanding, by providing children with alternative response formats, would increase children’s attribution of moral emotions and moral motivation. In Study 1, 93 4- to 7-year-old British children responded to the happy victimizer questions either in a normal condition (where they spontaneously pointed with a finger), a wait condition (where they had to wait before giving their answers), or an arrow condition (where they had to point with a paper arrow). In Study 2, 40 Spanish 4-year-old children responded in the happy victimizer task either in a normal or a wait condition. In both studies, participants’ attribution of moral emotions and moral motivation was significantly higher in the conditions with alternative response formats (wait, arrow) than in the normal condition. The role of cognitive abilities for emotion attribution in the happy victimizer task is discussed
    • 

    corecore