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Recent progress and challenges in exploiting graphics processors in computational fluid dynamics
Get PDFThe progress made in accelerating simulations of fluid flow using GPUs, and the challenges that remain, are surveyed. The review first provides an introduction to GPU computing and programming, and discusses various considerations for improved performance. Case studies comparing the performance of CPU- and GPUbased solvers for the Laplace and incompressible Navier–Stokes equations are performed in order to demonstrate the potential improvement even with simple codes. Recent efforts to accelerate CFD simulations using GPUs are reviewed for laminar, turbulent, and reactive flow solvers. Also, GPU implementations of the lattice Boltzmann method are reviewed. Finally, recommendations for implementing CFD codes on GPUs are given and remaining challenges are discussed, such as the need to develop new strategies and redesign algorithms to enable GPU acceleration.Keywords: Graphics processing unit (GPU), Reactive flow, Computational fluid dynamics (CFD), Laminar flows, Turbulent flow, CUD
Gardening with Oregon native plants west of the Cascades
No full textThis publication includes growing information, suggested plant combinations, and color photos of dozens of western Oregon native plants.Keywords: groundcovers, trees, shrubs, native plants, annuals, herbaceous perennials and ferns, plant selectionPublished October 2005. Reviewed August 2012. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo
Cretaceous-to-recent record of elevated ³He/⁴He along the Hawaiian-Emperor volcanic chain
Get PDFHelium isotopes are a robust geochemical tracer of a primordial mantle component in hot spot volcanism. The high ³He/⁴He (up to 35 RA, where RA is the atmospheric ³He/⁴He ratio of 1.39 X 10¯⁶) of some Hawaiian Island volcanism is perhaps the classic example. New results for picrites and basalts from the Hawaiian-Emperor seamount chain indicate that the hot spot has produced high ³He/⁴He lavas for at least the last 76 million years. Picrites erupted at 76 Ma have ³He/⁴He (10-14 RA), which is at the lower end of the range for the Hawaiian Islands but still above the range of modern mid-ocean ridge basalt (MORB; 6-10 RA). This was at a time when hot spot volcanism was occurring on thin lithosphere close to a spreading ridge and producing lava compositions otherwise nearly indistinguishable from MORB. After the hot spot and spreading center diverged during the Late Cretaceous, the hot spot produced lavas with significantly higher ³He/⁴He (up to 24 RA). Although ³He/⁴He ratios stabilized at relatively high values by 65 Ma, other chemical characteristics such as La/Yb and ⁸⁷Sr/⁸⁶Sr did not reach and stabilize at Hawaiian-Island-like values until ~45 Ma. Our limited ³He/⁴He record for the Hawaiian hot spot shows a poor correlation with plume flux estimates (calculated from bathymetry and residual gravity anomalies [Van Ark and Lin, 2004]). If ³He is a proxy for the quantity of primordial mantle material within the plume, then the lack of correlation between ³He/⁴He and calculated plume flux suggests that variation in primordial mantle flux is not the primary factor controlling total plume flux.Keywords: helium, Hawaiian-Emperor chain, MOR
Systolic and Diastolic Blood Pressure, Incident Cardiovascular Events and Death in Elderly Persons: The Role of Functional Limitation
Get PDFBACKGROUND: Whether limitation in ability to perform activities of daily living (ADL) or gait speed can identify subgroups of elders in whom the association of systolic (SBP) and diastolic (DBP) blood pressure with cardiovascular events and death differs is not well established.
METHODS: We evaluated whether ADL and gait speed modify the association of SBP or DBP with incident cardiovascular (CV) events (N= 2,358) and all-cause death (N=3,547) among participants in the 7th visit of the Cardiovascular Health Study. We used multivariable Cox regression adjusting for potential confounders.
RESULTS: Mean age was 78 ± 5 years and 21% reported limitation in ≥1 ADL. There were 778 incident CV events and 1,289 deaths over approximately 9 years. Among persons without and with ADL limitation, SBP was directly associated CVD events, and the size of the HRs was similar in the two groups: HR (per 10 mmHg increase) 1.08 (95% CI 1.03, 1.13) and 1.06 (0.97, 1.17), respectively. ADL modified the association of DBP with incident CVD. Among those without ADL limitations, DBP was weakly associated with CVD, HR 1.04 (0.79, 1.37) for DBP > 80 compared to 80 mmHg, compared to DBP ≤ 65 mmHg. Among persons with ADL limitation, a DBP 66-80 had the lowest risk for death, HR 0.72 (0.57, 0.91), compared with DBP ≤ 65 mmHg. Associations of BP with CVD or death did not vary by 15 feet walking speed.
CONCLUSIONS: ADL can identify the subgroups of elders in whom diastolic hypotension is associated with higher CV risk and death. Functional status, rather than chronologic age, should inform design of trials to elucidate benefits and harms of lowering each BP component in elders.Keywords: hypertension, activities of daily living, age
The effects of re‐homogenization on plagioclase hosted melt inclusions
Get PDFMelt inclusions trapped in phenocrysts provide a unique picture of magma systems prior to modification by crustal processes. However, post-entrapment crystallization complicates their interpretation. Re-heating the phenocryst to the temperature of entrapment is a commonly applied method to recover the original melt composition. To understand the effects of re-homogenization, we compared the composition of re-heated and naturally quenched melt inclusions and inclusion compositions that had been subjected to over-heating and under-heating to examine the degree to which anomalous compositions were produced. Our results on plagioclase hosted inclusions from ocean floor basalts indicate that the general patterns represented by naturally quenched inclusions are the same as observed for rehomogenized inclusions. Most important, the range of minor elements described for plagioclase hosted inclusions from basalts is found in naturally quenched inclusions, and is therefore not a consequence of the re-homogenization process.This is the publisher's version of record. The original submission is copyrighted by American Geophysical Union and can be found here: http://www.agu.org/pubs/journals
Shoreline variability from days to decades : results of long-term video imaging
Get PDFThe present work characterizes the time-space scales of variability and forcing dependencies of a unique 26 year record of daily to hourly shoreline data from a steep beach at Duck, North Carolina. Shoreline positions over a 1500 m alongshore span were estimated using a new algorithm called ASLIM based on fitting the band of high light intensity in time exposure images to a local Gaussian fit, with a subsequent Kalman filter to reduce noise and uncertainty. Our findings revealed that the shoreline change at long times scales dominates seasonal variability, despite that wave forcing had only 2% variance at interannual frequencies. The shoreline response presented 66% of the variance at interannual scales. These results were not expected since from wave forcing it would have been expected that the shoreline response should similarly lack interannual variability, but we found it to be dominated by this scale. The alongshore-mean shoreline time series revealed no significant annual cycle. However, there are annual oscillations in the shoreline response that are coherent with wave forcing and deserves further explanations. The pier was found to have a significant influence on shoreline behavior since restricts the seasonal longshore transport between the sides, resulting in a seasonally reversing sediment accumulation. Thus, there is a significant annual peak in shoreline variability that is coherent with the annual forcing but becomes insignificant in the longshore-average.Keywords: interannual variability, shoreline variability, wave forcing, video remote sensin
Subclinical Vascular Disease Burden and Longer Survival
Get PDFOBJECTIVES: Subclinical vascular disease (SVD) contributes to the aging process and may decrease life expectancy. We aimed to determine the contribution of gradations of SVD to the likelihood of achieving longer survival, and to determine what allows some individuals to achieve longer survival in the presence of high SVD.
DESIGN: Cohort Study
SETTING: Cardiovascular Health Study
PARTICIPANTS: Adults who were born after June 30th, 1918 and before June 30th, 1921 (n=2,082); participants were age 70-75 years at baseline visit (1992-1993).
MEASUREMENTS: A SVD index was scored as 0, 1, or 2 for no, mild, or severe abnormalities on ankle-arm index, electrocardiogram, and common carotid intima-media thickness measured at baseline. Survival groups were categorized as <80, 80-84, 85-89, and 90+ years.
RESULTS: A one point lower SVD score was associated with a 1.22 (95% confidence interval: 1.14, 1.31) higher odds of achieving longer survival, independent of potential confounders. This association was unchanged after adjustment for intermediate incident cardiovascular events. There was suggestion of an interaction of kidney function, smoking, and CRP with SVD; the association of SVD and longer survival appeared modestly increased in persons with poor kidney function, inflammation, or a history of smoking.
CONCLUSION: A lower burden of SVD is associated with longer survival, and this association was independent of intermediate cardiovascular events. Abstinence from smoking, better kidney function, and lower inflammation may attenuate the effects of higher SVD and further promote longer survival.This is an author's peer-reviewed final manuscript, as accepted by the publisher. The article is copyrighted by the authors; the Journal compilation is copyrighted by the American Geriatrics Society and published by John Wiley & Sons, Inc. It can be found at: http://onlinelibrary.wiley.com/journal/10.1111/%28ISSN%291532-5415Keywords: kidney function, inflammation, smoking, survival, cardiovascular disease, subclinical diseas
Nonlinear ⁴⁰Ar/³⁹Ar age systematics along the Gilbert Ridge and Tokelau Seamount Trail and the timing of the Hawaii-Emperor Bend
Get PDFOver the last three decades the first-order correlation in morphology and orientation of seamount trails
has been called upon to support the concept of a ‘‘fixed’’ Pacific hot spot frame of reference and to explain
the Hawaii-Emperor bend (HEB) by a dramatic change in Pacific plate motion. In this paper, however, we
present ⁴⁰Ar/³⁹Ar ages for the Gilbert Ridge and Tokelau Seamounts (Pacific) that show similar changes or
bends in their orientation, but at different geological times, up to 20 Myr earlier than the HEB. Changes in
Pacific plate motion alone cannot explain these observations, because these asynchronous bends should
have been reflected in the morphology of each of these seamount trails. Together with the lack of (linear)
age progressions and inconsistent apparent local plate velocities of 131 and 87 mm/yr, we rule out a fixed
hot spot origin for the Gilbert Ridge and Tokelau seamount trails. Instead we invoke secondary or alternate
processes to explain the complex age systematics and morphologies in these seamount trails. We propose
here that the HEB-type bends in these seamount trails were likely formed by short-term ‘‘jerk-like’’ plate
extensions in the studied southwestern region of the Pacific plate, reactivating a preconditioned lithosphere
that can be characterized by a complex structure and precursory magmatic impingements. The remarkable
differences observed in these colinear seamount trails fundamentally question the existence of HEB-type
bends in the formation of Pacific volcanic lineaments. They also show us that applying geometric and
morphologic observations alone is insufficient in constraining past plate motions. Nevertheless, the need
and search for alternate volcano-tectonic mechanisms offer opportunities to better understand intraplate
volcanism in general.Keywords: local lithospheric extension, seamounts, intraplate volcanism, Pacific plate, ⁴⁰Ar/³⁹Ar geochronology, hot spot
Rearing in a distorted magnetic field disrupts the ‘map sense’ of juvenile steelhead trout
Get PDFWe used simulated magnetic displacements to test orientation preferences of juvenile steelhead trout (Oncorhynchus mykiss) exposed to magnetic fields existing at the northernmost and southernmost boundaries of their oceanic range. Fish reared in natural magnetic conditions distinguished between these two fields by orienting in opposite directions, with headings that would lead fish towards marine foraging grounds. However, fish reared in a spatially distorted magnetic field failed to distinguish between the experimental fields and were randomly oriented. The non-uniform field in which fish were reared is probably typical of fields that many hatchery fish encounter due to magnetic distortions associated with the infrastructure of aquaculture. Given that the reduced navigational abilities we observed could negatively influence marine survival, homing ability and hatchery efficiency, we recommend further study on the implications of rearing salmonids in unnatural magnetic fields.Keywords: magnetic map, navigation, salmon, trou
Safety and Pharmacokinetic Profiles of Phosphorodiamidate Morpholino Oligomers with Activity against Ebola Virus and Marburg Virus: Results of Two Single-Ascending-Dose Studies
Get PDFTwo identical single-ascending-dose studies evaluated the safety and pharmacokinetics (PK) of AVI-6002 and AVI-6003, two experimental combinations of phosphorodiamidate morpholino oligomers with positive charges (PMOplus) that target viral mRNA encoding Ebola virus and Marburg virus proteins, respectively. Both AVI-6002 and AVI-6003 were found to suppress disease in virus-infected nonhuman primates in previous studies. AVI-6002 (a combination of AVI-7537 and AVI-7539) or AVI-6003 (a combination of AVI-7287 and AVI-7288) were administered as sequential intravenous (i.v.) infusions of a 1:1 fixed dose ratio of the two subcomponents. In each study, 30 healthy male and female subjects between 18 and 50 years of age were enrolled in six-dose escalation cohorts of five subjects each and received a single i.v. infusion of active study drug (0.005, 0.05, 0.5, 1.5, 3, and 4.5 mg/kg per component) or placebo in a 4:1 ratio. Both AVI-6002 and AVI-6003 were safe and well tolerated at the doses studied. A maximum tolerated dose was not observed in either study. The four chemically similar PMOplus components exhibited generally similar PK profiles. The mean peak plasma concentration and area under the concentration-time curve values of the four components exhibited dose-proportional PK. The estimated plasma half-life of all four components was 2 to 5 h. The safety of the two combinations and the PK of the four components were similar, regardless of the target RNA sequence.Keywords: Marburg virus, Ebola virus, Single-ascending-dose studies, Phosphorodiamidate morpholino oligomer