1,438 research outputs found
Evaluation of remote sensing for the detection of landfill gas and leachate in an urban environment
The technique of remote sensing provides a unique view of the earth's surface and considerable areas can be surveyed in a short amount of time. The aim of this project was to evaluate whether remote sensing, particularly using the Airborne Thematic Mapper (ATM) with its wide spectral range, was capable of monitoring landfill sites within an urban environment with the aid of image processing and Geographical Information Systems (GIS) methods. The regions under study were in the West Midlands conurbation and consisted of a large area in what is locally known as the Black Country containing heavy industry intermingled with residential areas, and a large single active landfill in north Birmingham. When waste is collected in large volumes it decays and gives off pollutants. These pollutants, landfill gas and leachate (a liquid effluent), are known to be injurious to vegetation and can cause stress and death. Vegetation under stress can exhibit a physiological change, detectable by the remote sensing systems used. The chemical and biological reactions that create the pollutants are exothermic and the gas and leachate, if they leave the waste, can be warmer than their surroundings. Thermal imagery from the ATM (daylight and dawn) and thermal video were obtained and used to find thermal anomalies on the area under study. The results showed that vegetation stress is not a reliable indicator of landfill gas migration, as sites within an urban environment have a cover too complex for the effects to be identified. Gas emissions from two sites were successfully detected by all the thermal imagery with the thermal ATM being the best. Although the results were somewhat disappointing, recent technical advancements in the remote sensing systems used in this project would allow geo-registration of ATM imagery taken on different occasions and the elimination of the effects of solar insolation
Immunological studies on the light-harvesting polypeptides of photosystems I and II
AbstractMonoclonal and polyclonal antibodies have been raised against the three apoproteins of the peripheral light-harvesting complex of photosystem I (LHC I) from Pisum sativum L. These antibodies have been used to study the immunological relatedness of the light-harvesting polypeptides of photosystems I and II. The results suggest that there is no immunological/structural relationship between the two light-harvesting systems. The apoproteins of the LHC I fall into two distinct groups corresponding to the two chlorophyllab complexes comprising the PS I antenna
Expected Performance of CryoArray
WIMP-nucleon cross sections below 10^(-9) pb may be probed by ton-scale
experiments with low thresholds and background rates ~20 events per year. An
array of cryogenic detectors ("CryoArray") could perform well enough to reach
this goal. Sufficient discrimination and background suppression of photons has
already been demonstrated. Reduction of neutron backgrounds may be achieved by
siting the experiment deep enough. Removal of the surface-electron backgrounds
alone has not yet been demonstrated, but the reductions required even for this
troublesome background are quite modest and appear achieveable.Comment: 4 pages, 2 figures. Talk at DM2002 Conference, Marina del Rey, CA,
Feb 20-22, 200
Use of apomorphine in Parkinsonian patients with neuropsychiatric complications to oral treatment
Neuropsychiatric side effects often complicate anti-Parkinsonian therapy and pose a significant problem in the optimal management of idiopathic Parkinson's disease. Several publications report a relative lack of neuropsychiatric side effects in Parkinsonian patients treated with subcutaneous apomorphine. To investigate this further, we have used subcutaneous apomorphine to treat 12 non-demented IPD patients with previous oral drug-related neuropsychiatric problems. Treatment with apomorphine allowed alteration of anti-Parkinsonian medication and led to the abolition or reduction of neuropsychiatric complications in all patients. The mechanism remains unclear but may be due, in part, to a reduction in oral medication or a psychotropic action of apomorphine, possibly due to the piperidine moiety in its structure, or both
Mod-Gaussian convergence and its applications for models of statistical mechanics
In this paper we complete our understanding of the role played by the
limiting (or residue) function in the context of mod-Gaussian convergence. The
question about the probabilistic interpretation of such functions was initially
raised by Marc Yor. After recalling our recent result which interprets the
limiting function as a measure of "breaking of symmetry" in the Gaussian
approximation in the framework of general central limit theorems type results,
we introduce the framework of -mod-Gaussian convergence in which the
residue function is obtained as (up to a normalizing factor) the probability
density of some sequences of random variables converging in law after a change
of probability measure. In particular we recover some celebrated results due to
Ellis and Newman on the convergence in law of dependent random variables
arising in statistical mechanics. We complete our results by giving an
alternative approach to the Stein method to obtain the rate of convergence in
the Ellis-Newman convergence theorem and by proving a new local limit theorem.
More generally we illustrate our results with simple models from statistical
mechanics.Comment: 49 pages, 21 figure
Scalar one-loop integrals for QCD
We construct a basis set of infra-red and/or collinearly divergent scalar
one-loop integrals and give analytic formulas, for tadpole, bubble, triangle
and box integrals, regulating the divergences (ultra-violet, infra-red or
collinear) by regularization in dimensions. For scalar triangle
integrals we give results for our basis set containing 6 divergent integrals.
For scalar box integrals we give results for our basis set containing 16
divergent integrals. We provide analytic results for the 5 divergent box
integrals in the basis set which are missing in the literature. Building on the
work of van Oldenborgh, a general, publicly available code has been
constructed, which calculates both finite and divergent one-loop integrals. The
code returns the coefficients of and
as complex numbers for an arbitrary tadpole, bubble, triangle or box integral.Comment: 27 pages, 5 figures, associated fortran code available at
http://qcdloop.fnal.gov/. New version corrects typographical error in Eq. 5.
Resummation of Nonalternating Divergent Perturbative Expansions
A method for the resummation of nonalternating divergent perturbation series
is described. The procedure constitutes a generalization of the Borel-Pad\'{e}
method. Of crucial importance is a special integration contour in the complex
plane. Nonperturbative imaginary contributions can be inferred from the purely
real perturbative coefficients. A connection is drawn from the quantum field
theoretic problem of resummation to divergent perturbative expansions in other
areas of physics.Comment: 5 pages, LaTeX, 2 tables, 1 figure; discussion of the Carleman
criterion added; version to appear in Phys. Rev.
Mean Hα+[N ii]+[S ii] EW inferred for star-forming galaxies atz ~ 5.1-5.4 using high-qualitySpitzer/IRAC photometry
W hadroproduction at large transverse momentum beyond next-to-leading order
We study the production of W bosons at large transverse momentum in p pbar
collisions. We show that the next-to-leading order cross section at large
transverse momentum is dominated by threshold soft-gluon corrections. We add
next-to-next-to-leading-order soft-gluon corrections to the exact
next-to-leading-order differential cross sections. We find that these
higher-order corrections provide modest enhancements to the transverse momentum
distribution of the W at the Tevatron, and reduce significantly the dependence
on the factorization and renormalization scales.Comment: 17 pages, 8 figure
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