197 research outputs found
Petrochemical and petrophysical characterization of the lower crust and the Moho beneath the West African Craton, based on Xenoliths from Kimberlites
Additional evidence to the composition of the lower crust and uppermost mantle was presented in the form of xenolith data. Xenoliths from the 2.7-Ga West African Craton indicate that the Moho beneath this shield is a chemically and physically gradational boundary, with intercalations of garnet granulite and garnet eclogite. Inclusions in diamonds indicate a depleted upper mantle source, and zenolith barometry and thermometry data suggest a high mantle geotherm with a kink near the Moho. Metallic iron in the xenoliths indicates that the uppermost mantle has a significant magnetization, and that the depth to the Curie isotherm, which is usually considered to be at or above the Moho, may be deeper than the Moho
The National Extension Oil and Gas Initiative
The national Extension oil and gas initiative centers on a network of Extension educators working on or interested in oil and gas development, a communications strategy that allows network members to exchange Extension information, a comprehensive inventory of Extension activities and resources, and national meetings at which network members can identify and share resources and optimal ways to engage constituents. Our work suggests that the need for relevant training and programming will continue as Extension faculty anticipate increased community demands surrounding oil and gas development. The network is open to all Extension faculty interested in the topic of oil and gas programming in communities
The Importance of Heat Flux in Quasi-Parallel Collisionless Shocks
Collisionless plasma shocks are a common feature of many space and
astrophysical systems and are sources of high-energy particles and non-thermal
emission, channeling as much as 20\% of the shock's energy into non-thermal
particles. The generation and acceleration of these non-thermal particles have
been extensively studied, however, how these particles feed back on the shock
hydrodynamics has not been fully treated. This work presents the results of
self-consistent hybrid particle-in-cell simulations that show the effect of
self-generated non-thermal particle populations on the nature of collisionless,
quasi-parallel shocks. They contribute to a significant heat flux density
upstream of the shock. Non-thermal particles downstream of the shock leak into
the upstream region, taking energy away from the shock. This increases the
compression ratio, slows the shock down, and flattens the non-thermal
population's spectral index for lower Mach number shocks. We incorporate this
into a revised theory for the Rankine-Hugoniot jump conditions that include
this effect and it shows excellent agreement with simulations. The results have
the potential to explain discrepancies between predictions and observations in
a wide range of systems, such as inaccuracies of predictions of arrival times
of coronal mass ejections and the conflicting radio and x-ray observations of
intracluster shocks.
These effects will likely need to be included in fluid modeling to accurately
predict shock evolution.Comment: 7 pages, 3 figures, a lot of appendi
Revolutionizing our Understanding of Particle Energization in Space Plasmas Using On-Board Wave-Particle Correlator Instrumentation
The development of on-board wave-particle correlator instrumentation using existing instrumental capabilities makes it possible to probe the collisionless wave-particle interactions governing plasma heating and particle acceleration in the heliosphere at full measurement cadence while circumventing telemetry constraints, enabling us to maximize the scientific return from future missions
Time-averaged ventilation for optimized control of variable-air-volume systems
Typical Variable Air Volume (VAV) terminals spend the majority of time at their minimum airflow setpoints. These are often higher than the minimum ventilation requirements defined by code, resulting in excess energy use and a risk of over-cooling the spaces. We developed and tested a Time-Averaged Ventilation (TAV) control strategy in an institutional building on the UC Berkeley campus to address this issue. Whenever a zone does not require cooling, TAV alternates the VAV damper between partially open and fully closed so that the average airflow matches a predefined ventilation setpoint. Compared to the existing, base case scenario using single-max VAV logic, this strategy reduced the mean zone airflow fraction from 0.44 to 0.27 during the intervention period. The corresponding reductions in average heating, cooling, and fan power were 41%, 23%, and 15% respectively. In addition to being programmed directly in a native control system, TAV may be applied via sMAP as a low-cost retrofit strategy in any building that has a BACnet network and direct digital control (DDC) to each VAV terminal
LSST Science Book, Version 2.0
A survey that can cover the sky in optical bands over wide fields to faint
magnitudes with a fast cadence will enable many of the exciting science
opportunities of the next decade. The Large Synoptic Survey Telescope (LSST)
will have an effective aperture of 6.7 meters and an imaging camera with field
of view of 9.6 deg^2, and will be devoted to a ten-year imaging survey over
20,000 deg^2 south of +15 deg. Each pointing will be imaged 2000 times with
fifteen second exposures in six broad bands from 0.35 to 1.1 microns, to a
total point-source depth of r~27.5. The LSST Science Book describes the basic
parameters of the LSST hardware, software, and observing plans. The book
discusses educational and outreach opportunities, then goes on to describe a
broad range of science that LSST will revolutionize: mapping the inner and
outer Solar System, stellar populations in the Milky Way and nearby galaxies,
the structure of the Milky Way disk and halo and other objects in the Local
Volume, transient and variable objects both at low and high redshift, and the
properties of normal and active galaxies at low and high redshift. It then
turns to far-field cosmological topics, exploring properties of supernovae to
z~1, strong and weak lensing, the large-scale distribution of galaxies and
baryon oscillations, and how these different probes may be combined to
constrain cosmological models and the physics of dark energy.Comment: 596 pages. Also available at full resolution at
http://www.lsst.org/lsst/sciboo
Is patient satisfaction with organizational aspects of their general practitioner’s practice associated with patient and doctor gender? An observational study
The PHENIX Experiment at RHIC
The physics emphases of the PHENIX collaboration and the design and current
status of the PHENIX detector are discussed. The plan of the collaboration for
making the most effective use of the available luminosity in the first years of
RHIC operation is also presented.Comment: 5 pages, 1 figure. Further details of the PHENIX physics program
available at http://www.rhic.bnl.gov/phenix
Dual use of Medicare and the Veterans Health Administration: are there adverse health outcomes?
BACKGROUND: Millions of veterans are eligible to use the Veterans Health Administration (VHA) and Medicare because of their military service and age. This article examines whether an indirect measure of dual use based on inpatient services is associated with increased mortality risk. METHODS: Data on 1,566 self-responding men (weighted N = 1,522) from the Survey of Assets and Health Dynamics among the Oldest Old (AHEAD) were linked to Medicare claims and the National Death Index. Dual use was indirectly indicated when the self-reported number of hospital episodes in the 12 months prior to baseline was greater than that observed in the Medicare claims. The independent association of dual use with mortality was estimated using proportional hazards regression. RESULTS: 96 (11%) of the veterans were classified as dual users. 766 men (50.3%) had died by December 31, 2002, including 64.9% of the dual users and 49.3% of all others, for an attributable mortality risk of 15.6% (p < .003). Adjusting for demographics, socioeconomics, comorbidity, hospitalization status, and selection bias at baseline, as well as subsequent hospitalization for ambulatory care sensitive conditions, the independent effect of dual use was a 56.1% increased relative risk of mortality (AHR = 1.561; p = .009). CONCLUSION: An indirect measure of veterans' dual use of the VHA and Medicare systems, based on inpatient services, was associated with an increased risk of death. Further examination of dual use, especially in the outpatient setting, is needed, because dual inpatient and dual outpatient use may be different phenomena
- …