296 research outputs found
The Upper Devonian Sandstone aquifer of Fife
The Devonian sandstone aquifer of Fife has long been recognised as one of the most important
hydrogeological units in Scotland. Its importance was first acknowledged by Earp and Eden (1961),
and the aquifer was later described by Foster et al (1976). Data were subsequently gathered together
in map form (BGS, 1986) but little analysis of the aquifer was carried out other than a dissertation
prepared by Barker (1981), occasional reports on specific issues such as nitrate pollution (e.g. Frost
and Sargent, 1993; MacDonald, 1993; Ball, 1994), and the preparation of the 1: 100 000 scale Aquifer
Vulnerability Map of Fife (SEPA, 1999).
The aquifer currently supplies some 20 Ml/d during the winter, rising to 40 Ml/d in the summer
months, when irrigation boreholes are put into use. Groundwater provides an important back up to
public water supplies, particularly during dry years when river abstraction is restricted. Despite this,
relatively little is known about the overall renewable resource potential of the aquifer. It is also only
in recent years that means of safeguarding groundwater from pollution have been investigated in any
detail.
Renewed interest in the aquifer is now being driven on two fronts. The first is that the East of
Scotland Water Authority (ESWA) needs to expand its source provision due to increasing demand.
The second is that the Scottish Environment Protection Agency (SEPA) needs to look more closely at
the aquifer potential if in the future groundwater abstraction licensing is introduced in significant
aquifers (Robins and Ball, 1998). In addition, the requirements of the proposed EU Water Framework
Directive indicate that a greater understanding of the aquifer and the sources it supplies will be needed
in order to implement properly integrated surface and groundwater management on a catchment basis.
With these goals in mind, the East of Scotland Water Authority, Scottish Environment Protection
Agency and NERC have jointly commissioned this preliminary study of the Eden valley aquifer
JWalk: a tool for lazy, systematic testing of java classes by design introspection and user interaction
Popular software testing tools, such as JUnit, allow frequent retesting of modified code; yet the manually created test scripts are often seriously incomplete. A unit-testing tool called JWalk has therefore been developed to address the need for systematic unit testing within the context of agile methods. The tool operates directly on the compiled code for Java classes and uses a new lazy method for inducing the changing design of a class on the fly. This is achieved partly through introspection, using Javaâs reflection capability, and partly through interaction with the user, constructing and saving test oracles on the fly. Predictive rules reduce the number of oracle values that must be confirmed by the tester. Without human intervention, JWalk performs bounded exhaustive exploration of the classâs method protocols and may be directed to explore the space of algebraic constructions, or the intended design state-space of the tested class. With some human interaction, JWalk performs up to the equivalent of fully automated state-based testing, from a specification that was acquired incrementally
Introduction to the functional RG and applications to gauge theories
These lectures contain an introduction to modern renormalization group (RG)
methods as well as functional RG approaches to gauge theories. In the first
lecture, the functional renormalization group is introduced with a focus on the
flow equation for the effective average action. The second lecture is devoted
to a discussion of flow equations and symmetries in general, and flow equations
and gauge symmetries in particular. The third lecture deals with the flow
equation in the background formalism which is particularly convenient for
analytical computations of truncated flows. The fourth lecture concentrates on
the transition from microscopic to macroscopic degrees of freedom; even though
this is discussed here in the language and the context of QCD, the developed
formalism is much more general and will be useful also for other systems.Comment: 60 pages, 14 figures, Lectures held at the 2006 ECT* School
"Renormalization Group and Effective Field Theory Approaches to Many-Body
Systems", Trento, Ital
Nucleon charge exchange on the deuteron: A critical review
The existing experimental data on the d(n,p)nn and d(p,n)pp cross sections in
the forward direction are reviewed in terms of the Dean sum rule. It is shown
that the measurement of the ratio of the charge exchange on the deuteron to
that on the proton might, if taken together with other experimental data, allow
a direct construction of the np -> np scattering amplitude in the backward
direction with few ambiguities.Comment: 7 pages with 3 figure
Automated Classification of Sloan Digital Sky Survey (SDSS) Stellar Spectra using Artificial Neural Networks
Automated techniques have been developed to automate the process of
classification of objects or their analysis. The large datasets provided by
upcoming spectroscopic surveys with dedicated telescopes urges scientists to
use these automated techniques for analysis of such large datasets which are
now available to the community. Sloan Digital Sky Survey (SDSS) is one of such
surveys releasing massive datasets. We use Probabilistic Neural Network (PNN)
for automatic classification of about 5000 SDSS spectra into 158 spectral type
of a reference library ranging from O type to M type stars.Comment: 27 pages, 11 figures To appear in Astrophys. Space Sci., 200
Nonperturbative renormalization group approach to frustrated magnets
This article is devoted to the study of the critical properties of classical
XY and Heisenberg frustrated magnets in three dimensions. We first analyze the
experimental and numerical situations. We show that the unusual behaviors
encountered in these systems, typically nonuniversal scaling, are hardly
compatible with the hypothesis of a second order phase transition. We then
review the various perturbative and early nonperturbative approaches used to
investigate these systems. We argue that none of them provides a completely
satisfactory description of the three-dimensional critical behavior. We then
recall the principles of the nonperturbative approach - the effective average
action method - that we have used to investigate the physics of frustrated
magnets. First, we recall the treatment of the unfrustrated - O(N) - case with
this method. This allows to introduce its technical aspects. Then, we show how
this method unables to clarify most of the problems encountered in the previous
theoretical descriptions of frustrated magnets. Firstly, we get an explanation
of the long-standing mismatch between different perturbative approaches which
consists in a nonperturbative mechanism of annihilation of fixed points between
two and three dimensions. Secondly, we get a coherent picture of the physics of
frustrated magnets in qualitative and (semi-) quantitative agreement with the
numerical and experimental results. The central feature that emerges from our
approach is the existence of scaling behaviors without fixed or pseudo-fixed
point and that relies on a slowing-down of the renormalization group flow in a
whole region in the coupling constants space. This phenomenon allows to explain
the occurence of generic weak first order behaviors and to understand the
absence of universality in the critical behavior of frustrated magnets.Comment: 58 pages, 15 PS figure
Production and Decay of D_1(2420)^0 and D_2^*(2460)^0
We have investigated and final states and
observed the two established charmed mesons, the with mass
MeV/c and width MeV/c and
the with mass MeV/c and width
MeV/c. Properties of these final states, including
their decay angular distributions and spin-parity assignments, have been
studied. We identify these two mesons as the doublet predicted
by HQET. We also obtain constraints on {\footnotesize } as a function of the cosine of the relative phase of the two
amplitudes in the decay.Comment: 15 pages in REVTEX format. hardcopies with figures can be obtained by
sending mail to: [email protected]
Relating the microscopic rules in coalescence-fragmentation models to the macroscopic cluster size distributions which emerge
Coalescence-fragmentation problems are of great interest across the physical,
biological, and recently social sciences. They are typically studied from the
perspective of the rate equations, at the heart of such models are the rules
used for coalescence and fragmentation. Here we discuss how changes in these
microscopic rules affect the macroscopic cluster-size distribution which
emerges from the solution to the rate equation. More generally, our work
elucidates the crucial role that the fragmentation rule can play in such
dynamical grouping models. We focus on two well-known models whose
fragmentation rules lie at opposite extremes setting the models within the
broader context of binary coalescence-fragmentation models. Further, we provide
a range of generalizations and new analytic results for a well-known model of
social group formation [V. M. Eguiluz and M. G. Zimmermann, Phys. Rev. Lett.
85, 5659 (2000)]. We develop analytic perturbation treatment of the original
model, and extend the mathematical to the treatment of growing and declining
populations
Transcript- and annotation-guided genome assembly of the European starling
First published: 28 June 2022The European starling, Sturnus vulgaris, is an ecologically significant, globally invasive avian species that is also suffering from a major decline in its native range. Here, we present the genome assembly and long- read transcriptome of an Australian-sourced European starling (S. vulgaris vAU), and a second, North American, short- read genome assembly (S. vulgaris vNA), as complementary reference genomes for population genetic and evolutionary characterization. S. vulgaris vAU combined 10Ă genomics linked- reads, low-coverage Nanopore sequencing, and PacBio Iso-Seq full- length transcript scaffolding to generate a 1050 Mb assembly on 6222 scaffolds (7.6 Mb scaffold N50, 94.6% busco completeness). Further scaffolding against the high-quality zebra finch (Taeniopygia guttata) genome assigned 98.6% of the assembly to 32 puta-tive nuclear chromosome scaffolds. Species-specific transcript mapping and gene an-notation revealed good gene- level assembly and high functional completeness. Using S. vulgaris vAU, we demonstrate how the multifunctional use of PacBio Iso-Seq tran-script data and complementary homology-based annotation of sequential assembly steps (assessed using a new tool, saaga) can be used to assess, inform, and validate assembly workflow decisions. We also highlight some counterintuitive behaviour in traditional busco metrics, and present buscomp, a complementary tool for assembly comparison designed to be robust to differences in assembly size and base-calling quality. This work expands our knowledge of avian genomes and the available toolkit for assessing and improving genome quality. The new genomic resources presented will facilitate further global genomic and transcriptomic analysis on this ecologically important species.Katarina C. Stuart, Richard J. Edwards, Yuanyuan Cheng, Wesley C. Warren, David W. Burt, William B. Sherwin, Natalie R. Hofmeister, Scott J. Werner, Gregory F. Ball, Melissa Bateson, Matthew C. Brandley, Katherine L. Buchanan, Phillip Cassey, David F. Clayton, Tim De Meyer, Simone L. Meddle, Lee A. Rollin
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