16,412 research outputs found
Authorizing Tolkien: Control, Adaptation, and Dissemination of J.R.R. Tolkien\u27s Works
This article is the introduction to the special theme issue consisting of four essays on Authorizing Tolkien. Reid and Elam discuss medieval and postmodern theories of adaptation and interpretation and introduce the essays in the issue
Logarithmic coarsening and glassy behavior in a polymer model with mass-dependent diffusion
We present a model of polymer growth and diffusion with frustration
mechanisms for density increase and with diffusion rates of Arrhenius form with
mass-dependent energy barriers Gamma(m) ~ (m-1)^gamma. It shows non-universal
logarithmic coarsening involving the exponent gamma. Strong-glass behavior is
found in the typical times for disappearance of all polymers up to a given
length, without reference to the equilibrium states of the macroscopic system.
These features are predicted by numerical simulations, scaling theories and an
analytic solution of the master equation within an independent interval
approximation, which also provides the cluster size distribution.Comment: 16 pages, including 7 figures. To be published in Phys. Rev.
Recommended from our members
SOAR (Support Office for Aerogeophysical Research) Annual Report 1994/1995
The Support Office for Aerogeophysical Research (SOAR) was a facility of the National Science Foundation's Office of Polar Programs whose mission is to make airborne geophysical observations available to the broad research community of geology, glaciology and other sciences. The central office of the SOAR facility is located in Austin, Texas within the University of Texas Institute for Geophysics. Other institutions with significant responsibilities are the Lamont Doherty Earth Observatory of Columbia University and the Geophysics Branch of the U.S . Geological Survey. This report summarizes the goals and accomplishments of the SOAR facility during 1994/1995 and plans for the next year.National Science Foundation's Office of Polar ProgramsInstitute for Geophysic
Artificial reef plan for sport fish enhancement
Hard bottom substrate provides habitat for a multitude of marine fishes, invertebrates, and plants - particularly giant kelp - which are of direct and indirect importance to sport and commercial fisheries. These reefs also enhance
esthetic uses of the marine environment. This document sets forth the plan of the California Department of Fish and Game (CDFG) for the construction of artificial reefs.
The plan includes an outline for defining the purpose of reef construction, gathering information pertinent to reef placement and design, selecting a reef site, preparing a project narrative, obtaining permits and approvals for reef construction, developing a general permit for reef construction, and establishing a system of fisheries habitat enhancement areas. Procedures for constructing and mapping
reefs are discussed and an outline for conducting short- and long-term biological studies of reef communities is presented.
Since 1958, CDFG has constructed 31 reefs off southern California. Thirteen of the largest and most frequently used reefs were mapped using hydroacoustic and radio-locating techniques. Maps of these reefs were published in a 1989 CDFG booklet entitled "A Guide to the Artificial Reefs of Southern California".
Since 1978, seven developmental reefs have been constructed: 1) Pendleton Artificial Reef (1980) - San Diego County;
2) Pitas Point Artificial Reef (1984) Ventura County;
3) Marina Del Rey Artificial Reef (1985) - Los Angeles County; 4)Oceanside Artificial Reef (1987) - San Diego County; 5) Pacific Beach Artificial Reef (1987) - San Diego County; 6) Santa Monica Artificial Reef (1987) - Los
Angeles County; and 7) Topanga Artificial Reef (1987) - Los Angeles County. These reefs were built to improve habitat for sport fishes and associated fauna and to evaluate the enhancement characteristics of reefs related to geographic
location, depth, height, rock size, and reef spacing.
Short-term studies revealed that all reefs have provided shelter, food, nesting, and nursery areas for important fish species and have increased sport fishing opportunities. Furthermore, giant kelp has been observed on all reefs built at suitable depths. More extensive long-term studies are planned in 1998 when reef communities will be at successional equilibrium. These studies will provide
additional information concerning the long-term potential of artificial reefs as habitat for sport fish, invertebrates, and plants.
The plan discusses different types of man-made reefs, including developmental, production, and fishing access reefs, and provides examples of each. It documents
CDFG policy regarding the use of reefs as mitigation for impacts on rocky habitat and kelp. It also documents the laws authorizing CDFG to administer reef construction and studies in California. The activities involved in designing,
permitting, constructing, and evaluating Pendleton Artificial Reef are provided as an example of the reef building and study process.
A list of reefs is provided to document the location, depth, area, materials, and funding sources for all reefs constructed and/or augmented in California. (85pp.
Diverse Long-Term Variability of Five Candidate High-Mass X-ray Binaries from Swift Burst Alert Telescope Observations
We present an investigation of long-term modulation in the X-ray light curves
of five little-studied candidate high-mass X-ray binaries using the Swift Burst
Alert Telescope. IGR J14488-5942 and AX J1700.2-4220 show strong modulation at
periods of 49.6 and 44 days, respectively, which are interpreted as orbital
periods of Be star systems. For IGR J14488-5942, observations with Swift X-ray
Telescope show a hint of pulsations at 33.4 s. For AX J1700.2-4220, 54 s
pulsations were previously found with XMM. Swift J1816.7-1613 exhibits
complicated behavior. The strongest peak in the power spectrum is at a period
near 150 days, but this conflicts with a determination of a period of 118.5
days by La Parola et al. (2014). AX J1820.5-1434 has been proposed to exhibit
modulation near 54 days, but the extended BAT observations suggest modulation
at slightly longer than double this at approximately 111 days. There appears to
be a long-term change in the shape of the modulation near 111 days, which may
explain the apparent discrepancy. The X-ray pulsar XTE J1906+090, which was
previously proposed to be a Be star system with an orbital period of ~30 days
from pulse timing, shows peaks in the power spectrum at 81 and 173 days. The
origins of these periods are unclear, although they might be the orbital period
and a superorbital period respectively. For all five sources, the long-term
variability, together with the combination of orbital and proposed pulse
periods, suggests that the sources contain Be star mass donors.Comment: Accepted for publication in The Astrophysical Journal. 15 pages, 27
figures. (v2 corrects citation
New surveys of UBV photometry and absolute proper motions at intermediate latitude
A photometric and proper motion survey has been obtained in 2 directions at
intermediate latitude: (, ;
,) and
(, ; ,
). The survey covers 7.13 and 20.84 square
degrees, respectively. The limiting magnitude is about 18.5 in V for both
directions. We have derived the density laws for stars (M 3.5) as a
function of distance from the galactic plane. The density laws for stars follow
a sum of two exponentials with scale heights of 240 pc (thin disk) and 790 pc
(thick disk), respectively. The local density of thick disk is found to be
6.13 % relative to the thin disk. The kinematical distribution of stars
has been probed to distances up to 3.5 kpc above the galactic plane. New
estimates of the parameters of velocity ellipsoid have been derived for the
thick disk of the Galaxy. A comparison of our data sets with the Besan\c con
model star count predictions has been performed, giving a good agreement in the
magnitude range V = 13 to 18.Comment: 13 pages, 8 PS figures, To appear in A&
The Galactic bulge as seen in optical surveys
The bulge is a region of the Galaxy of tremendous interest for understanding
galaxy formation. However measuring photometry and kinematics in it raises
several inherent issues, such as severe crowding and high extinction in the
visible. Using the Besancon Galaxy model and a 3D extinction map, we estimate
the stellar density as a function of longitude, latitude and apparent magnitude
and we deduce the possibility of reaching and measuring bulge stars with Gaia.
We also present an ongoing analysis of the bulge using the Canada-France-Hawaii
Telescope.Comment: In SF2A-2008: Proceedings of the Annual meeting of the French Society
of Astronomy and Astrophysic
MCMC-ODPR : primer design optimization using Markov Chain Monte Carlo sampling
Background
Next generation sequencing technologies often require numerous primer designs that require good target coverage that can be financially costly. We aimed to develop a system that would implement primer reuse to design degenerate primers that could be designed around SNPs, thus find the fewest necessary primers and the lowest cost whilst maintaining an acceptable coverage and provide a cost effective solution. We have implemented Metropolis-Hastings Markov Chain Monte Carlo for optimizing primer reuse. We call it the Markov Chain Monte Carlo Optimized Degenerate Primer Reuse (MCMC-ODPR) algorithm.
Results
After repeating the program 1020 times to assess the variance, an average of 17.14% fewer primers were found to be necessary using MCMC-ODPR for an equivalent coverage without implementing primer reuse. The algorithm was able to reuse primers up to five times. We compared MCMC-ODPR with single sequence primer design programs Primer3 and Primer-BLAST and achieved a lower primer cost per amplicon base covered of 0.21 and 0.19 and 0.18 primer nucleotides on three separate gene sequences, respectively. With multiple sequences, MCMC-ODPR achieved a lower cost per base covered of 0.19 than programs BatchPrimer3 and PAMPS, which achieved 0.25 and 0.64 primer nucleotides, respectively.
Conclusions
MCMC-ODPR is a useful tool for designing primers at various melting temperatures at good target coverage. By combining degeneracy with optimal primer reuse the user may increase coverage of sequences amplified by the designed primers at significantly lower costs. Our analyses showed that overall MCMC-ODPR outperformed the other primer-design programs in our study in terms of cost per covered base
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