867 research outputs found
A moving baseline for evaluation of advanced coal extraction systems
Results from the initial effort to establish baseline economic performance comparators for a program whose intent is to define, develop, and demonstrate advanced systems suitable for coal resource extraction beyond the year 2000 are reported. Systems used were selected from contemporary coal mining technology and from conservation conjectures of year 2000 technology. The analysis was also based on a seam thickness of 6 ft. Therefore, the results are specific to the study systems and the selected seam extended to other seam thicknesses
Recommended from our members
The East Midlands in 2010
The East Midlands in 2010 is the updated evidence base that supports the regional economic strategy, A Flourishing Region. It presents a statistical portrait of the region covering demography, housing, economy & productivity, the labour market, deprivation & economic inclusion, transport, infrastructure & development, the environment and the spatial structure of the economy along with a series of sub-regional profiles
Recommended from our members
The East Midlands in 2010: economy
The East Midlands in 2010 is the updated evidence base that supports the regional economic strategy, A Flourishing Region. This document presents detailed analysis of the economy of the East Midlands
Search for Supermassive Black Hole Binaries in the Sloan Digital Sky Survey Spectroscopic Sample
Supermassive black hole (SMBH) binaries are expected in a Lambda CDM
cosmology given that most (if not all) massive galaxies contain a massive black
hole at their center. So far, however, direct evidence for such binaries has
been elusive. We use cross-correlation to search for temporal velocity shifts
in the MgII broad emission lines of 0.36 < z < 2 quasars with multiple
observations in the Sloan Digital Sky Survey. For ~ 10^9 Msun BHs in SMBH
binaries, we are sensitive to velocity drifts for binary separations of ~ 0.1
pc with orbital periods of ~100 years. We find seven candidate sub-pc--scale
binaries with velocity shifts > 3.4 sigma ~ 280 km/s, where sigma is our
systematic error. Comparing the detectability of SMBH binaries with the number
of candidates (N < 7), we can rule out that most 10^9 Msun BHs exist in ~
0.03-0.2 pc scale binaries, in a scenario where binaries stall at sub-pc scales
for a Hubble time. We further constrain that < one-third of quasars host SMBH
binaries after considering gas-assisted sub-pc evolution of SMBH binaries,
although this result is very sensitive to the assumed size of the broad line
region. We estimate the detectability of SMBH binaries with ongoing or
next-generation surveys (e.g., BOSS, Subaru Prime Focus Spectrograph), taking
into account the evolution of the sub-parsec binary in circumbinary gas disks.
These future observations will provide longer time baselines for searches
similar to ours and may in turn constrain the evolutionary scenarios of SMBH
binaries.Comment: Resubmitted to ApJ after referee's comments. 21 pages, 9 figure
Comprehensive, atomic-level characterization of structurally characterized protein-protein interactions: the PICCOLO database.
BACKGROUND: Structural studies are increasingly providing huge amounts of information on multi-protein assemblies. Although a complete understanding of cellular processes will be dependent on an explicit characterization of the intermolecular interactions that underlie these assemblies and mediate molecular recognition, these are not well described by standard representations. RESULTS: Here we present PICCOLO, a comprehensive relational database capturing the details of structurally characterized protein-protein interactions. Interactions are described at the level of interacting pairs of atoms, residues and polypeptide chains, with the physico-chemical nature of the interactions being characterized. Distance and angle terms are used to distinguish 12 different interaction types, including van der Waals contacts, hydrogen bonds and hydrophobic contacts. The explicit aim of PICCOLO is to underpin large-scale analyses of the properties of protein-protein interfaces. This is exemplified by an analysis of residue propensity and interface contact preferences derived from a much larger data set than previously reported. However, PICCOLO also supports detailed inspection of particular systems of interest. CONCLUSIONS: The current PICCOLO database comprises more than 260 million interacting atom pairs from 38,202 protein complexes. A web interface for the database is available at http://www-cryst.bioc.cam.ac.uk/piccolo.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are
A Bayesian approach to the analysis of time symmetry in light curves: Reconsidering Scorpius X-1 occultations
We present a new approach to the analysis of time symmetry in light curves,
such as those in the x-ray at the center of the Scorpius X-1 occultation
debate. Our method uses a new parameterization for such events (the bilogistic
event profile) and provides a clear, physically relevant characterization of
each event's key features. We also demonstrate a Markov Chain Monte Carlo
algorithm to carry out this analysis, including a novel independence chain
configuration for the estimation of each event's location in the light curve.
These tools are applied to the Scorpius X-1 light curves presented in Chang et
al. (2007), providing additional evidence based on the time series that the
events detected thus far are most likely not occultations by TNOs.Comment: 24 pages, 18 figures. Preprint typeset using LaTeX style emulateapj
v. 04/20/0
Recommended from our members
NET phase two local economic evaluation: report 2: impact evaluation findings: final report
Recommended from our members
Scoping education needs and provision for walk-in-centres in North East London
Kolmogorov-Sinai entropy in field line diffusion by anisotropic magnetic turbulence
The Kolmogorov-Sinai (KS) entropy in turbulent diffusion of magnetic field
lines is analyzed on the basis of a numerical simulation model and theoretical
investigations. In the parameter range of strongly anisotropic magnetic
turbulence the KS entropy is shown to deviate considerably from the earlier
predicted scaling relations [Rev. Mod. Phys. {\bf 64}, 961 (1992)]. In
particular, a slowing down logarithmic behavior versus the so-called Kubo
number (, where is the ratio of the rms magnetic fluctuation field to the magnetic field
strength, and and are the correlation lengths in respective
dimensions) is found instead of a power-law dependence. These discrepancies are
explained from general principles of Hamiltonian dynamics. We discuss the
implication of Hamiltonian properties in governing the paradigmatic
"percolation" transport, characterized by , associating it with the
concept of pseudochaos (random non-chaotic dynamics with zero Lyapunov
exponents). Applications of this study pertain to both fusion and astrophysical
plasma and by mathematical analogy to problems outside the plasma physics.
This research article is dedicated to the memory of Professor George M.
ZaslavskyComment: 15 pages, 2 figures. Accepted for publication on Plasma Physics and
Controlled Fusio
The TAOS Project: Upper Bounds on the Population of Small KBOs and Tests of Models of Formation and Evolution of the Outer Solar System
We have analyzed the first 3.75 years of data from TAOS, the Taiwanese
American Occultation Survey. TAOS monitors bright stars to search for
occultations by Kuiper Belt Objects (KBOs). This dataset comprises 5e5
star-hours of multi-telescope photometric data taken at 4 or 5 Hz. No events
consistent with KBO occultations were found in this dataset. We compute the
number of events expected for the Kuiper Belt formation and evolution models of
Pan & Sari (2005), Kenyon & Bromley (2004), Benavidez & Campo Bagatin (2009),
and Fraser (2009). A comparison with the upper limits we derive from our data
constrains the parameter space of these models. This is the first detailed
comparison of models of the KBO size distribution with data from an occultation
survey. Our results suggest that the KBO population is comprised of objects
with low internal strength and that planetary migration played a role in the
shaping of the size distribution.Comment: 18 pages, 16 figures, Aj submitte
- …