What Does the Future Hold for the Sustainability of GMOs in Our Environment?

This article talks about the effects of GMOs on food chains and whether or not they are sustainable in regards to the future. The advantages and disadvantages of GMOs are addressed and considered when deciding whether or not they are sustainable

Hepatitis C virus screening practices and seropositivity among US veterans born during 1945 - 1965.

BACKGROUND: The Centers for Disease Control and Prevention (CDC) and the United States Preventive Services Task Force (USPSTF) recently augmented risk-based hepatitis C (HCV) screening guidelines with a recommendation to perform one-time screening in all persons born during 1945 - 1965, a birth cohort known to have a higher prevalence of HCV. We sought to estimate the proportion of veterans seen at the Atlanta VA Medical Center (AVAMC) who had ever been screened for HCV infection by birth year. METHODS: We used an administrative database of all veterans seen at the AVAMC between January 1, 2011 and December 31, 2011, and a laboratory generated list of all HCV antibody tests and HCV RNA viral loads that were performed at the AVAMC to determine receipt of screening and HCV antibody positivity. Odds ratios and 95% confidence intervals were estimated using SAS version 9.2 (SAS institute, Cary, North Carolina). RESULTS: HCV antibody testing had ever been performed on 48% (41,556) of the veterans seen in 2011; 10% of those tested had a positive antibody. Confirmatory viral loads were performed in 96% of those with a positive antibody screen. Those born during 1945 - 1965 were more likely to have a HCV antibody performed when compared with those born in other years (54% vs. 41%, odds ratio [OR] 1.70, 95% Confidence Interval [CI] 1.65-1.74). Among veterans ever tested for HCV antibody (n = 41,556), those born during 1945 - 1965 were 6 times more likely to have a positive HCV antibody (15% vs. 3%, OR 5.87, 95% CI 5.32-6.78), and 3 times more likely to have chronic HCV infection (76% vs. 50%, OR 3.25, 95% CI 2.65-4.00). CONCLUSIONS: Nearly half of the veterans seen in 2011 at the AVAMC had ever been tested for HCV infection. When examined by birth cohort, over half of the veterans born during 1945 - 1965 had been screened for HCV and 15% of those screened had a positive HCV antibody. Our findings confirm the increased prevalence of HCV infection in persons born during 1945 - 1965 as identified in the updated CDC and USPSTF recommendations

Improved GNSS-R bi-static altimetry and independent digital elevation models of Greenland and Antarctica from TechDemoSat-1

Improved digital elevation models (DEMs) of the Antarctic and Greenland ice sheets are presented, which have been derived from Global Navigation Satellite Systems-Reflectometry (GNSS-R). This builds on a previous study (Cartwright et al., 2018) using GNSS-R to derive an Antarctic DEM but uses improved processing and an additional 13 months of measurements, totalling 46 months of data from the UK TechDemoSat-1 satellite. A median bias of under 10 m and root-mean-square errors (RMSEs) of under 53 m for the Antarctic and 166 m for Greenland are obtained, as compared to existing DEMs. The results represent, compared to the earlier study, a halving of the median bias to 9 m, an improvement in coverage of 18 %, and a 4 times higher spatial resolution (now gridded at 25 km). In addition, these are the first published satellite altimetry measurements of the region surrounding the South Pole. Comparisons south of 88∘ S yield RMSEs of less than 33 m when compared to NASA's Operation IceBridge measurements. Differences between DEMs are explored, the limitations of the technique are noted, and the future potential of GNSS-R for glacial ice studies is discussed

Effect of Drying Rate on Shrinkage of Alkali-Activated Slag Cements

The volumetric instability of alkali-activated slag (AAS) binders has raised concerns and impeded the acceptance of this Portland cement-free material. The objective of this article is to characterize the influence of drying rate on drying shrinkage behavior of AAS mortars to better understand the mechanisms responsible for its large shrinkage deformation. A series of four AAS mortar mixtures with varying activator composition, as well as a reference Portland cement mortar, was cast and dried at different relative humidities, that is, 30, 50, 70, and 85% RH. Drying took place inside nitrogen-purged environmental chambers for the purpose of eliminating the contribution of carbonation to the total volumetric change of AAS. The shrinkage and corresponding mass loss of 1.27 cm × 1.27 cm × 12.7 cm prisms were measured as a function of time. The results show that shrinkage of AAS varies largely depending on the drying rate, that is, ambient RH. Interestingly, even though the drying mass loss increases with reducing the RH, the magnitude of shrinkage is the largest for samples stored at 50 and 70% RH, depending on the mixture type. Possible causes of these irregular behaviors are discussed. It is concluded that the drying rate has a much more significant influence on AAS than on ordinary Portland cement (OPC), which implies a more complicated shrinkage mechanism for AAS samples stored at various relative humidities

Episodic fluid venting from sedimentary basins fuelled by pressurised mudstones

Subsurface sandstone reservoirs sealed by overlying, low-permeability layers provide capacity for long-term sequestration of anthropogenic waste. Leakage can occur if reservoir pressures rise sufficiently to fracture the seal. Such pressures can be generated within the reservoir by vigorous injection of waste or, over thousands of years, by natural processes. In either case, the precise role of intercalated mudstones in the long-term evolution of reservoir pressure remains unclear; these layers have variously been viewed as seals, as pressure sinks, or as pressure sources. Here, we use the geological record of episodic fluid venting in the Levant Basin to provide striking evidence for the pressure-source hypothesis. We use a Bayesian framework to combine recently published venting data, which record critical subsurface pressures since ∼2 Ma, with a stochastic model of pressure evolution to infer a pressure-recharge rate of ∼30 MPa/Myr. To explain this large rate, we quantify and compare a range of candidate mechanisms. We find that poroelastic pressure diffusion from mudstones provides the most plausible explanation for these observations, amplifying the ∼3 MPa/Myr recharge caused primarily by tectonic compression. Since pressurized mudstones are ubiquitous in sedimentary basins, pressure diffusion from mudstones is likely to promote seal failure globally

Stokes at 200: A celebration of the remarkable achievements of Sir George Gabriel Stokes two hundred years after his birth

Sir George Gabriel Stokes PRS was for 30 years an inimitable Secretary of the Royal Society and its President from 1885 to 1890. Two hundred years after his birth, Stokes is a towering figure in physics and applied mathematics; fluids, asymptotics, optics, acoustics among many other fields. At the Stokes200 meeting, held at Pembroke College, Cambridge from 15-18th September 2019, an invited audience of about 100 discussed the state of the art in all the modern research fields that have sprung from his work in physics and mathematics, along with the history of how we have got from Stokes' contributions to where we are now. This theme issue is based on work presented at the Stokes200 meeting. In bringing together people whose work today is based upon Stokes' own, we aim to emphasize his influence and legacy at 200 to the community as a whole. This article is part of the theme issue 'Stokes at 200 (Part 1)'

Stokes at 200 (part 2)

We present the second half of the papers from the Stokes200 symposium celebrating the bicentenary of George Gabriel Stokes. This article is part of the theme issue 'Stokes at 200 (part 2)'

Episodic, compression-driven fluid venting in layered sedimentary basins

Fluid venting phenomena are prevalent in sedimentary basins globally. Offshore, these localised fluid-expulsion events are archived in the geologic record via the resulting pockmarks at the sea-floor. Venting is widely interpreted to occur via hydraulic fracturing, which requires near-lithostatic pore pressures for initiation. One common driver for these extreme pressures is horizontal tectonic compression, which pressurises the entire sedimentary column over a wide region. Fluid expulsion leads to a sudden, local relief of this pressure, which then gradually recharges through continued compression, leading to episodic venting. Pressure recharge will also occur through pressure diffusion from neighboring regions that remain pressurised, but the combined role of compression and pressure diffusion in episodic venting has not previously been considered. Here, we develop a novel poroelastic model for episodic, compression-driven venting. We show that compression and pressure diffusion together set the resulting venting period. We derive a simple analytical expression for this venting period, demonstrating that pressure diffusion can significantly reduce the venting period associated with a given rate of compression and allowing this rate of compression to be inferred from observations of episodic venting. Our results indicate that pressure diffusion is a major contributor to episodic fluid venting in mudstone-dominated basins

Episodic fluid venting from sedimentary basins fuelled by pressurised mudstones

Subsurface sandstone reservoirs sealed by overlying, low-permeability layers provide capacity for long-term sequestration of anthropogenic waste. Leakage can occur if reservoir pressures rise sufficiently to fracture the seal. Such pressures can be generated within the reservoir by vigorous injection of waste or, over thousands of years, by natural processes. In either case, the precise role of intercalated mudstones in the long-term evolution of reservoir pressure remains unclear; these layers have variously been viewed as seals, as pressure sinks or as pressure sources. Here, we use the geological record of episodic fluid venting in the Levant Basin to provide striking evidence for the pressure-source hypothesis. We use a Bayesian framework to combine recently published venting data, which record critical subsurface pressures since $\sim$2 Ma, with a stochastic model of pressure evolution to infer a pressure-recharge rate of $\sim$30 MPa/Myr. To explain this large rate, we quantify and compare a range of candidate mechanisms. We find that poroelastic pressure diffusion from mudstones provides the most plausible explanation for these observations, amplifying the $\sim$1 MPa/Myr recharge caused by tectonic compression. Since pressurised mudstones are ubiquitous in sedimentary basins, pressure diffusion from mudstones is likely to promote seal failure globally

EAT 1

1. William Slaughter - Like Atlantis 00:27 2. Tim Gilmore - A Saying of Graces 02:57 3. Clark Lunberry & Jason Arnold - Reconsider Now 04:02 4. Keith Cartwright with Jesse Cartwright - Bloomdido 02:08 5. Mark Ari as Cyrano Moon - Under the Influence: Part 1 04:12 6. Clark Lunberry & Jason Arnold - As If / To Drift 03:11 7. William Slaughter - What I Learned Living in an Olive Grove 00:16 8. Mark Ari as Cyrano Moon with Blind Willie Sixpence - I’ll Be Glad When You’re Gone 02:12 9. Clark Lunberry & Jason Arnold - Eavesdropping Across America 05:32 10. Thelma Young - Ria 11:28 11. Christopher Sylvester - Morning Trawl 03:4312. April Fisher - Mine 02:44 13. Tim Gilmore - Leaving Word 07:03 14. K. Hassall - Sabbatical Report: A Compulsory Study in Violence(bonus) 28:06https://digitalcommons.unf.edu/eat/1000/thumbnail.jp