Price Formation under Small Numbers Competition: Evidence from Land Auctions in Singapore

This paper examines the price formation process under small numbers competition using data from Singapore land auctions. The theory predicts that bid prices are less than the zero-profit asset value in these first-price sealed-bid auctions. The model also shows that expected sales price increases with the number of bidders both because each bidder has an incentive to offer a higher price and because of a greater likelihood that a high-value bidder is present. The empirical estimates are consistent with auction theory and show that the standard land attributes are reflected in auction prices as expected. Working Paper No. 04-0

Wilson ratio of a Tomonaga-Luttinger liquid in a spin-1/2 Heisenberg ladder

Using micromechanical force magnetometry, we have measured the magnetization of the strong-leg spin-1/2 ladder compound (C$_7$H$_{10}$N)$_2$CuBr$_2$ at temperatures down to 45 mK. Low-temperature magnetic susceptibility as a function of field exhibits a maximum near the critical field H_c at which the magnon gap vanishes, as expected for a gapped one-dimensional antiferromagnet. Above H_c a clear minimum appears in the magnetization as a function of temperature as predicted by theory. In this field region, the susceptibility in conjunction with our specific heat data yields the Wilson ratio R_W. The result supports the relation R_W=4K, where K is the Tomonaga-Luttinger-liquid parameter

ESR modes in a Strong-Leg Ladder in the Tomonaga-Luttinger Liquid Phase

Magnetic excitations in the strong-leg quantum spin ladder compound (C$_7$H$_{10}$N)$_2$CuBr$_4$ (known as DIMPY) in the field-induced Tomonaga-Luttinger spin liquid phase are studied by means of high-field electron spin resonance (ESR) spectroscopy. The presence of a gapped ESR mode with unusual non-linear frequency-field dependence is revealed experimentally. Using a combination of analytic and exact diagonalization methods, we compute the dynamical structure factor and identify this mode with longitudinal excitations in the antisymmetric channel. We argue that these excitations constitute a fingerprint of the spin dynamics in a strong-leg spin-1/2 Heisenberg antiferromagnetic ladder and owe its ESR observability to the uniform Dzyaloshinskii-Moriya interaction

Fisheries long term monitoring program : summary of tiger and endeavour prawn survey results: 1998-2006

There are two distinct tiger and endeavour prawn fisheries that extend along the northern Queensland east coast and into Torres Strait: the Torres Strait Prawn Fishery (TSPF) and the northern segment (north of 22° S) of the East Coast Trawl Fishery (ECTF). This document reports on the Torres Strait, and a section of the northern Queensland segment of the ECTF (defined as the section of the Queensland east coast from Cape Flattery 16° S to the tip of Cape York 10.4° S. This section will be referred to as Far North Queensland). The prawn trawl fishery in this Far North Queensland (FNQ) region mainly targets tiger, endeavour and king prawns. These three prawn groups consist of six main species: the brown tiger prawn (Penaeus esculentus), the grooved tiger prawn (Penaeus semisulcatus), the blue endeavour prawn (Metapenaeus endeavouri), the red endeavour prawn (Metapenaeus ensis), the redspot king prawn (Melicertus longistylus), and the western king prawn (Melicertus latisulcatus). The average annual catch (from 1998–2004) of the tiger and endeavour prawn sector of the northern Queensland ECTF (north of 22° S) is approximately 1700 t of tiger prawns, 1200 t of endeavour prawns and 900 t of king prawns (CFISH data, 1998–2004). For the Torres Strait the average annual catch (from 2000–04) is 675 t of tiger prawns, 1018 t of endeavour prawns and 77 t of king prawns (Taylor et al. 2006). The annual value of the northern Queensland and the Torres Strait prawn fisheries is approximately A$40m (Williams 2002) and A$22m, respectively (McLoughlin 2002). The initial annual prawn surveys (1998–2000) were a component of the Fisheries Research and Development Corporation project 97/146, conducted by Department of Primary Industries and Fisheries (DPI&F). The project developed a fishery independent sampling procedure for tiger and endeavour prawn stocks in northern Queensland and Torres Strait waters. The DPI&F Long Term Monitoring Program continued the annual prawn surveys, using the same survey procedures and sites. The key objective of the annual prawn surveys is to monitor prawn species, size, distribution and relative abundance in order to contribute to assessments of the status of tiger, endeavour and king prawns in northern Queensland and Torres Strait waters. The surveys also document bycatch in the fishery area to enhance understanding of the fishery’s potential impacts on the ecosystem. The survey results for FNQ indicate that 1999 and 2005 were years of higher than average tiger prawn recruitment while 2000 was a year of lower than average recruitment. Similarly, for Torres Strait, 2000 was a year of low tiger prawn recruitment whereas 1998, 2005 and 2006 were years of above average recruitment. The results presented in this report, a previous summary of survey results (Turnbull et al. 2004), and a detailed analysis of both the 1998 to 2002 surveys and commercial catch data (Turnbull et al. 2005) indicate that these surveys are a cost effective tool in providing the data needed to monitor prawn stocks, especially in multi-species fisheries such as the northern Queensland east coast tiger prawn fishery. The survey catch rates can be compared with, and provide confidence in, the trends observed in the commercial harvest data (Turnbull et al. 2005, O’Neill and Turnbull 2006, O’Neill and Leigh 2006) especially for tiger prawns which are considered susceptible to overfishing. It is recommended that the LTMP prawn surveys be continued as they provide an important time-series of fishery independent data that complements the analysis of the commercial fishery data. The survey data complements the commercial harvest data and will assist with the development of species-based assessment and monitoring of the northern Queensland tiger prawn fishery

Gauge-invariant magnetic perturbations in perfect-fluid cosmologies

We develop further our extension of the Ellis-Bruni covariant and gauge-invariant formalism to the general relativistic treatment of density perturbations in the presence of cosmological magnetic fields. We present detailed analysis of the kinematical and dynamical behaviour of perturbed magnetized FRW cosmologies containing fluid with non-zero pressure. We study the magnetohydrodynamical effects on the growth of density irregularities during the radiation era. Solutions are found for the evolution of density inhomogeneities on small and large scales in the presence of pressure, and some new physical effects are identified.Comment: Revised version (some minor changes - few equations added). 26 pages. No figures. To appear in Classical and Quantum Gravit

Neutron scattering from a coordination polymer quantum paramagnet

Inelastic neutron scattering measurements are reported for a powder sample of the spin-1/2 quantum paramagnet $\rm Cu(Quinoxaline)Br_2$. Magnetic neutron scattering is identified above an energy gap of 1.9 meV. Analysis of the sharp spectral maximum at the onset indicates that the material is magnetically quasi-one-dimensional. Consideration of the wave vector dependence of the scattering and polymeric structure further identifies the material as a two-legged spin-1/2 ladder. Detailed comparison of the data to various models of magnetism in this material based on the single mode approximation and the continuous unitary transformation are presented. The latter theory provides an excellent account of the data with leg exchange $J_{\parallel}=2.0$ meV and rung exchange $J_{\perp}=3.3$ meV.Comment: 10 pages, 11 figures, 1 tabl

Field-induced Tomonaga-Luttinger liquid phase of a two-leg spin-1/2 ladder with strong leg interactions

We study the magnetic-field-induced quantum phase transition from a gapped quantum phase that has no magnetic long-range order into a gapless phase in the spin-1/2 ladder compound bis(2,3-dimethylpyridinium) tetrabromocuprate (DIMPY). At temperatures below about 1 K, the specific heat in the gapless phase attains an asymptotic linear temperature dependence, characteristic of a Tomonaga-Luttinger liquid. Inelastic neutron scattering and the specific heat measurements in both phases are in good agreement with theoretical calculations, demonstrating that DIMPY is the first model material for an S=1/2 two-leg spin ladder in the strong-leg regime.Comment: 4.1 pages, 4 figures (Fig. 4 updated), to appear in Physical Review Letter

Finding the Needles in the Haystacks: High-Fidelity Models of the Modern and Archean Solar System for Simulating Exoplanet Observations

We present two state-of-the-art models of the solar system, one corresponding to the present day and one to the Archean Eon 3.5 billion years ago. Each model contains spatial and spectral information for the star, the planets, and the interplanetary dust, extending to 50 AU from the sun and covering the wavelength range 0.3 to 2.5 micron. In addition, we created a spectral image cube representative of the astronomical backgrounds that will be seen behind deep observations of extrasolar planetary systems, including galaxies and Milky Way stars. These models are intended as inputs to high-fidelity simulations of direct observations of exoplanetary systems using telescopes equipped with high-contrast capability. They will help improve the realism of observation and instrument parameters that are required inputs to statistical observatory yield calculations, as well as guide development of post-processing algorithms for telescopes capable of directly imaging Earth-like planets.Comment: Accepted for publication in PAS

Pseudomonas aeruginosa AES-1 exhibits increased virulence gene expression during chronic infection of cystic fibrosis lung

Pseudomonas aeruginosa, the leading cause of morbidity and mortality in people with cystic fibrosis (CF), adapts for survival in the CF lung through both mutation and gene expression changes. Frequent clonal strains such as the Australian Epidemic Strain-1 (AES-1), have increased ability to establish infection in the CF lung and to superimpose and replace infrequent clonal strains. Little is known about the factors underpinning these properties. Analysis has been hampered by lack of expression array templates containing CF-strain specific genes. We sequenced the genome of an acute infection AES-1 isolate from a CF infant (AES-1R) and constructed a non-redundant micro-array (PANarray) comprising AES-1R and seven other sequenced P. aeruginosa genomes. The unclosed AES-1R genome comprised 6.254Mbp and contained 6957 putative genes, including 338 not found in the other seven genomes. The PANarray contained 12,543 gene probe spots; comprising 12,147 P. aeruginosa gene probes, 326 quality-control probes and 70 probes for non-P. aeruginosa genes, including phage and plant genes. We grew AES-1R and its isogenic pair AES-1M, taken from the same patient 10.5 years later and not eradicated in the intervening period, in our validated artificial sputum medium (ASMDM) and used the PANarray to compare gene expression of both in duplicate. 675 genes were differentially expressed between the isogenic pairs, including upregulation of alginate, biofilm, persistence genes and virulence-related genes such as dihydroorotase, uridylate kinase and cardiolipin synthase, in AES-1M. Non-PAO1 genes upregulated in AES-1M included pathogenesis-related (PAGI-5) genes present in strains PACS2 and PA7, and numerous phage genes. Elucidation of these genes' roles could lead to targeted treatment strategies for chronically infected CF patients. © 2011 Naughton et al