Renormalization of Massive Lattice Fermions

The renormalization of a general action for massive lattice fermions is discussed. The analysis applies for all $m_q a$. Preliminary results for the self energy at one loop in perturbation theory are presented.Comment: 3 pages (you guessed it: to appear in Lattice '93), uuencoded PostScript file, FERMILAB-CONF-93/382-T and EFI 93-72. Regular PostScript file by anonymous ftp to fnth06.fnal.gov as pub/Fermilab-Pub/93.38

Investigation of the anticorrosion performance of lignin coatings after crosslinking with triethyl phosphate and their adhesion to a polyurethane topcoat

This study investigates the anticorrosion properties of sustainable organic coatings, which were prepared by dissolution of two different types of technical lignins - organosolv lignin (OL) and kraft lignin (KL) - in an organic solvent and applied onto iron-phosphated steel by airassisted spray coating. Influence of triethyl phosphate (TEP) as a crosslinking agent for lignin and its effect on the anticorrosion properties of coatings during 24 h of immersion in 3.5% NaCl were investigated. Results obtained from electrochemical impedance spectroscopy (EIS) of coated steels suggest that the initial protection performance (1 h immersion) of non-crosslinked OL is higher than that of KL. Nevertheless, KL coatings that contained TEP and were heat-treated at elevated temperature (180 °C) demonstrated the best overall anticorrosion performance. In contrast, a similar trend was not observed for OL coatings, which indicates that the structural properties of lignin may be a crucial factor in applicability of TEP as a crosslinking agent. In addition, a layer of polyurethane was applied on all the different types of lignin coatings prepared and their adhesion characteristics were studied by crosscut adhesion measurements (ISO 2409). These adhesion results revealed that neither KL-TEP nor OL-TEP coatings demonstrate proper adhesive characteristics with a polyurethane (PU) topcoat and consequently these coatings are not suitable for utilization as a primer coating for the PU topcoat studied

Renormalization of composite operators

The blocked composite operators are defined in the one-component Euclidean scalar field theory, and shown to generate a linear transformation of the operators, the operator mixing. This transformation allows us to introduce the parallel transport of the operators along the RG trajectory. The connection on this one-dimensional manifold governs the scale evolution of the operator mixing. It is shown that the solution of the eigenvalue problem of the connection gives the various scaling regimes and the relevant operators there. The relation to perturbative renormalization is also discussed in the framework of the $\phi^3$ theory in dimension $d=6$.Comment: 24 pages, revtex (accepted by Phys. Rev. D), changes in introduction and summar

Botanical gardens as key resources and hazards for biosecurity

Biodiversity and economic losses resulting from invasive plant pests and pathogens are increasing globally. For these impacts and threats to be managed effectively, appropriate methods of surveillance, detection and identification are required. Botanical gardens provide a unique opportunity for biosecurity as they accommodate diverse collections of exotic and native plant species. These gardens are also often located close to high-risk sites of accidental invasions such as ports and urban areas. This, coupled with routine activities such as the movement of plants and plant material, and visits by millions of people each year, place botanical gardens at risk to the arrival and establishment of pests and pathogens. Consequently, botanical gardens can pose substantial biosecurity risks to the environment, by acting as bridgeheads for pest and pathogen invasions. Here we review the role of botanical gardens in biosecurity on a global scale. The role of botanical gardens has changed over time. Initially, they were established as physic gardens (gardens with medicinal plants), and their links with academic institutions led to their crucial role in the accumulation and dissemination of botanical knowledge. During the second half of the 20th century, botanical gardens developed a strong focus on plant conservation, and in recent years there has been a growing acknowledgement of their value in biosecurity research as sentinel sites to identify pest and pathogen risks (novel pest-host associations); for early detection and eradication of pests and pathogens; and for host range studies. We identify eight specific biosecurity hazards associated with botanical gardens and note potential management interventions and the opportunities these provide for improving biosecurity. We highlight the value of botanical gardens for biosecurity and plant health research in general, and the need for strategic thinking, resources, and capacity development to make them models for best practices in plant health

CHANDRA Observations of X-ray Jet Structure on kpc to Mpc Scales

With its exquisite spatial resolution of better than 0.5 arcsecond, the Chandra observatory is uniquely capable of resolving and studying the spatial structure of extragalactic X-ray jets on scales of a few to a few hundred kilo-parsec. Our analyses of four recent Chandra images of quasar jets interpret the X-ray emission as inverse Compton scattering of high energy electrons on the cosmic microwave background. We infer that these jets are in bulk relativistic motion, carrying kinetic powers upwards of 10^46 ergs/s to distances of hundreds of kpc, with very high efficiency.Comment: 4 pages, 3 figures, to be published in the proceedings of the Bologna jet workshop, "The Physics of Relativistic Jets in the CHANDRA and XMM Era.

Separate and combined effects of oligofructose and inulin on post-weaning coli bacillosis and weight gain: a preliminary study

Trends for a reduction in the use of dietary antibiotic growth promoters have caused increased interest in the use of alternative feed additives to maintain 'gut health' after weaning. Oligofructose and inulin are 'prebiotic' fructan-containing carbohydrates purported to enhance 'gut health' in newly-weaned pigs by altering microbial diversity (Konstantinov, et al., 2003). However, their effects using a challenge model of post-weaning colibacillosis (PWC) have never been examined. The aim of the present study was to compare the separate and combined effects of oligofructose and inulin supplementation on the occurrence of diarrhoea and the weight performance in piglets experimentally challenged with enterotoxigenic E. coli (ETEC)

A slow gravity compensated Atom Laser

We report on a slow guided atom laser beam outcoupled from a Bose-Einstein condensate of 87Rb atoms in a hybrid trap. The acceleration of the atom laser beam can be controlled by compensating the gravitational acceleration and we reach residual accelerations as low as 0.0027 g. The outcoupling mechanism allows for the production of a constant flux of 4.5x10^6 atoms per second and due to transverse guiding we obtain an upper limit for the mean beam width of 4.6 \mu\m. The transverse velocity spread is only 0.2 mm/s and thus an upper limit for the beam quality parameter is M^2=2.5. We demonstrate the potential of the long interrogation times available with this atom laser beam by measuring the trap frequency in a single measurement. The small beam width together with the long evolution and interrogation time makes this atom laser beam a promising tool for continuous interferometric measurements.Comment: 7 pages, 8 figures, to be published in Applied Physics

Lectures on the functional renormalization group method

These introductory notes are about functional renormalization group equations and some of their applications. It is emphasised that the applicability of this method extends well beyond critical systems, it actually provides us a general purpose algorithm to solve strongly coupled quantum field theories. The renormalization group equation of F. Wegner and A. Houghton is shown to resum the loop-expansion. Another version, due to J. Polchinski, is obtained by the method of collective coordinates and can be used for the resummation of the perturbation series. The genuinely non-perturbative evolution equation is obtained in a manner reminiscent of the Schwinger-Dyson equations. Two variants of this scheme are presented where the scale which determines the order of the successive elimination of the modes is extracted from external and internal spaces. The renormalization of composite operators is discussed briefly as an alternative way to arrive at the renormalization group equation. The scaling laws and fixed points are considered from local and global points of view. Instability induced renormalization and new scaling laws are shown to occur in the symmetry broken phase of the scalar theory. The flattening of the effective potential of a compact variable is demonstrated in case of the sine-Gordon model. Finally, a manifestly gauge invariant evolution equation is given for QED.Comment: 47 pages, 11 figures, final versio

Reptiles as food: Predation of Australian reptiles by introduced red foxes compounds and complements predation by cats

Context: Invasive species are a major cause of biodiversity loss across much of the world, and a key threat to Australia’s diverse reptile fauna. There has been no previous comprehensive analysis of the potential impact of the introduced European red fox, Vulpes vulpes, on Australian reptiles. Aims: We seek to provide an inventory of all Australian reptile species known to be consumed by the fox, and identify characteristics of squamate species associated with such predation. We also compare these tallies and characteristics with reptile species known to be consumed by the domestic cat, Felis catus, to examine whether predation by these two introduced species is compounded (i.e. affecting much the same set of species) or complementary (affecting different groups of species). Methods: We collated records of Australian reptiles consumed by foxes in Australia, with most records deriving from fox dietary studies (tallying >35 000 samples). We modelled presence or absence of fox predation records against a set of biological and other traits, and population trends, for squamate species. Key results: In total, 108 reptile species (~11% of Australia’s terrestrial reptile fauna) have been recorded as consumed by foxes, fewer than that reported for cats (263 species). Eighty-six species have been reported to be eaten by both predators. More Australian turtle species have been reported as consumed by foxes than by cats, including many that suffer high levels of predation on egg clutches. Twenty threatened reptile species have been reported as consumed by foxes, and 15 by cats. Squamate species consumed by foxes are more likely to be undergoing population decline than those not known to be consumed by foxes. The likelihood of predation by foxes increased with squamate species’ adult body mass, in contrast to the relationship for predation by cats, which peaked at ~217 g. Foxes, but not cats, were also less likely to consume venomous snakes. Conclusions: The two introduced, and now widespread, predators have both compounding and complementary impacts on the Australian reptile fauna. Implications: Enhanced and integrated management of the two introduced predators is likely to provide substantial conservation benefits to much of the Australian reptile fauna