2,901 research outputs found
An assessment of the value of pastoral development in Northland
This paper presents the results of an economic study of
farm development in Northland. In this study, records
were collected of 32 dairy farm case histories which had
increased butterfat production by 105% in an average of
6 years, and 18 sheep farm case histories for which wool
production increased 116% over a 7-year period. Also
included are data supplied by the Lands and Survey Department
on the economic outcome of two land development
blocks. In this paper, attention is focused on the cash costs and
benefits of development and their valuation by economic
methods. Nevertheless, the deficiencies of this approach
are recognized, because cash costs and benefits are only one
dimension of the outcome of development and the method
used for valuing this outcome makes assumptions about
the values of the farmer and society.This research was generously funded by the Commercial Rank of Australia
to mark their 100th Anniversary
Reducing alcohol-related harm in the workplace a feasibility study of screening and brief interventions for hazardous drinkers
The SU(N) Matrix Model at Two Loops
Multi-loop calculations of the effective action for the matrix model are
important for carrying out tests of the conjectured relationship of the matrix
model to the low energy description of M-theory. In particular, comparison with
N-graviton scattering amplitudes in eleven-dimensional supergravity requires
the calculation of the effective action for the matrix model with gauge group
SU(N). A framework for carrying out such calculations at two loops is
established in this paper. The two-loop effective action is explicitly computed
for a background corresponding to the scattering of a single D0-brane from a
stack of N-1 D0-branes, and the results are shown to agree with known results
in the case N=2.Comment: 30 pages, 1 figure; v2 - typos corrected, references update
SUSY vertex algebras and supercurves
This article is a continuation of math.QA/0603633 Given a strongly conformal
SUSY vertex algebra V and a supercurve X we construct a vector bundle V_X on X,
the fiber of which, is isomorphic to V. Moreover, the state-field
correspondence of V canonically gives rise to (local) sections of these vector
bundles. We also define chiral algebras on any supercurve X, and show that the
vector bundle V_X, corresponding to a SUSY vertex algebra, carries the
structure of a chiral algebra.Comment: 50 page
Drug resistance in non-B subtype HIV-1: Impact of HIV-1 reverse transcriptase inhibitors
Human immunodeficiency virus (HIV) causes approximately 2.5 million new infections every year, and nearly 1.6 million patients succumb to HIV each year. Several factors, including cross-species transmission and error-prone replication have resulted in extraordinary genetic diversity of HIV groups. One of these groups, known as group M (main) contains nine subtypes (A-D, F-H and J-K) and causes ∼95% of all HIV infections. Most reported data on susceptibility and resistance to anti-HIV therapies are from subtype B HIV infections, which are prevalent in developed countries but account for only ∼12% of all global HIV infections, whereas non-B subtype HIV infections that account for ∼88% of all HIV infections are prevalent primarily in low and middle-income countries. Although the treatments for subtype B infections are generally effective against non-B subtype infections, there are differences in response to therapies. Here, we review how polymorphisms, transmission efficiency of drug-resistant strains, and differences in genetic barrier for drug resistance can differentially alter the response to reverse transcriptase-targeting therapies in various subtypes
Photometry and Spectroscopy of the Optical Companion to the Pulsar PSR J1740-5340 in the Globular Cluster NGC 6397
We present photometric and spectroscopic observations of the optical
companion to the millisecond radio pulsar PSR J1740-5340 in the globular
cluster NGC 6397. An analysis of the photometric variability in the B, V, and
I-bands indicates an inclination of the system of 43.9+-2.1 degrees if the
optical companion fills its Roche lobe (a semi-detached configuration). The
spectroscopic data show a radial velocity variation with a semi-amplitude of
K=137.2 +- 2.4 km/sec, and a system velocity gamma=17.6 +- 1.5 km/sec,
consistent with cluster membership. We use these results to derive a mass of
the optical companion of M1=0.296 +- 0.034 Msol and M2=1.53 +- 0.19 Msol for
the pulsar. There is evidence for secular change of the amplitude of the
optical light curve of the variable measured over seven years. The change does
not have interpretation and its presence complicates reliable determination of
the absolute parameters of the binary.Comment: 24 pages, 9 figures, submitted to A
Formation of '3D' multiplanet systems by dynamical disruption of multiple-resonance configurations
Assuming that giant planets are formed in thin protoplanetary discs, a '3D'
system can form, provided that the mutual inclination is excited by some
dynamical mechanism. Resonant interactions and close planetary encounters are
thought to be the primary inclination-excitation mechanisms, resulting in a
resonant and non-resonant system, respectively. Here we propose an alternative
formation scenario, starting from a system composed of three giant planets in a
nearly coplanar configuration. As was recently shown for the case of the Solar
system, planetary migration in the gas disc (Type II migration) can force the
planets to become trapped in a multiply resonant state. We simulate this
process, assuming different values for the planetary masses and mass ratios. We
show that such a triple resonance generally becomes unstable as the resonance
excites the eccentricities of all planets and planet-planet scattering sets in.
One of the three planets is typically ejected from the system, leaving behind a
dynamically 'hot' (but stable) two-planet configuration. The resulting
two-planet systems typically have large values of semimajor axial ratios (a1/a2
< 0.3), while the mutual inclination can be as high as 70{\deg}, with a median
of \sim30{\deg}. A small fraction of our two-planet systems (\sim5 per cent)
ends up in the stability zone of the Kozai resonance. In a few cases, the
triple resonance can remain stable for long times and a '3D' system can form by
resonant excitation of the orbital inclinations; such a three-planet system
could be stable if enough eccentricity damping is exerted on the planets.
Finally, in the single-planet resulting systems, which are formed when two
planets are ejected from the system, the inclination of the planet's orbital
plane with respect to the initial invariant plane -presumably the plane
perpendicular to the star's spin axis- can be as large as \sim40{\deg}.Comment: 9 pages, 5 figures, published in MNRA
Wess-Zumino Terms in Supersymmetric Gauge Theories
The Wess-Zumino term is constructed for supersymmetric QCD with two colors
and flavors, and is shown to correctly reproduce the anomalous Ward identities.
Supersymmetric QCD is also shown not to have topologically stable skyrmion
solutions because of baryon flat directions, which allow them to unwind. The
generalization of these results to other supersymmetric theories with quantum
modified constraints is discussed.Comment: 4 pages (revtex
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