Exchange Rates, Money and Relative Prices: The Dollar-Pound in the 1920's

This paper applies the analytical framework of the monetary approach to exchange rate determination to the analysis of the Dollar/Pound exchange rate during the first part of the 1920's. The analysis uses monthly data up to the return of Britain to gold in 1925. The equilibrium exchange rate is shown to be influenced by both real and monetary factors which operate through their influence on the relative demands and supplies of monies. Special attention is given to examination of the relationship between exchange rates and the relative price of traded to non-traded goods. In the empirical work the prices of traded goods are proxied by the wholesale price indices and the prices of non-traded are proxied by wages. One of the key findings of the paper is the estimate of the elasticity of the exchange rate with respect to the relative price of traded to non-traded goods. This elasticity is estimated with high precision and is shown to be .415 which provides an independent measure of the relative share of spending on non-traded goods. This estimate is consistent with other estimates obtained in studies of expenditure shares. The paper concluded with a dynamic simulation which indicates the satisfactory quality of the predictive ability of the model.

Nuclear gas dynamics in Arp 220 - sub-kiloparsec scale atomic hydrogen disks

We present new, high angular resolution (~0.22") MERLIN observations of neutral hydrogen (HI) absorption and 21-cm radio continuum emission across the central ~900 parsecs of the ultraluminous infrared galaxy, Arp220. Spatially resolved HI absorption is detected against the morphologically complex and extended 21-cm radio continuum emission, consistent with two counterrotating disks of neutral hydrogen, with a small bridge of gas connecting the two. We propose a merger model in which the two nuclei represent the galaxy cores which have survived the initial encounter and are now in the final stages of merging, similar to conclusions drawn from previous CO studies (Sakamoto, Scoville & Yun 1999). However, we suggest that instead of being coplanar with the main CO disk (in which the eastern nucleus is embedded), the western nucleus lies above it and, as suggested by bridge of HI connecting the two nuclei, will soon complete its final merger with the main disk. We suggest that the collection of radio supernovae (RSN) detected in VLBA studies in the more compact western nucleus represent the second burst of star formation associated with this final merger stage and that free-free absorption due to ionised gas in the bulge-like component can account for the observed RSN distribution. (Abridged)Comment: 26 pages including 8 figures and 1 table; accepted for publication in Ap

Space-time variation of malaria incidence in Yunnan province, China

BACKGROUND Understanding spatio-temporal variation in malaria incidence provides a basis for effective disease control planning and monitoring. METHODS Monthly surveillance data between 1991 and 2006 for Plasmodium vivax and Plasmodium falciparum malaria across 128 counties were assembled for Yunnan, a province of China with one of the highest burdens of malaria. County-level Bayesian Poisson regression models of incidence were constructed, with effects for rainfall, maximum temperature and temporal trend. The model also allowed for spatial variation in county-level incidence and temporal trend, and dependence between incidence in June-September and the preceding January-February. RESULTS Models revealed strong associations between malaria incidence and both rainfall and maximum temperature. There was a significant association between incidence in June-September and the preceding January-February. Raw standardised morbidity ratios showed a high incidence in some counties bordering Myanmar, Laos and Vietnam, and counties in the Red River valley. Clusters of counties in south-western and northern Yunnan were identified that had high incidence not explained by climate. The overall trend in incidence decreased, but there was significant variation between counties. CONCLUSION Dependence between incidence in summer and the preceding January-February suggests a role of intrinsic host-pathogen dynamics. Incidence during the summer peak might be predictable based on incidence in January-February, facilitating malaria control planning, scaled months in advance to the magnitude of the summer malaria burden. Heterogeneities in county-level temporal trends suggest that reductions in the burden of malaria have been unevenly distributed throughout the province.This project was supported by a University of Queensland New Research Scientist Start-Up Fund grant. RWS is a Wellcome Trust Principal Research Fellow (#079080) and receives additional support from the Wellcome Trust for the Malaria Atlas Project (MAP, http://www.map.ox.ac.uk)

Optical Imaging of Very Luminous Infrared Galaxy Systems: Photometric Properties and Late Evolution

A sample of 19 low redshift (0.03$<$z$<$0.07) very luminous infrared galaxy (VLIRG: $10^{11}L_\odot<$ L[8-1000 $\mu$m] $< 10^{12} L_\odot$) systems (30 galaxies) has been imaged in $B$, $V$, and $I$. These objects cover a luminosity range that is key to linking the most luminous infrared galaxies with the population of galaxies at large. We have obtained photometry for all of these VLIRG systems, the individual galaxies (when detached), and their nuclei, and the relative behavior of these classes has been studied in optical color-magnitude diagrams. The photometric properties of the sample are also compared with previously studied samples of ULIRGs. The mean observed photometric properties of VLIRG and ULIRG samples, considered as a whole, are indistinguishable at optical wavelengths. This suggests that not only ULIRG, but also the more numerous population of VLIRGs, have similar rest-frame optical photometric properties as the submillimeter galaxies (SMG), reinforcing the connection between low-{\it z} LIRGs -- high-{\it z} SMGs. When the nuclei of the {\it young} and {\it old} interacting systems are considered separately, some differences between the VLIRG and the ULIRG samples are found. In particular, the old VLIRGs are less luminous and redder than old ULIRG systems. If confirmed with larger samples, this behavior suggests that the late-stage evolution is different for VLIRGs and ULIRGs. Specifically, as suggested from spectroscopic data, the present photometric observations support the idea that the activity during the late phases of VLIRG evolution is dominated by starbursts, while a higher proportion of ULIRGs could evolve into a QSO type of object.Comment: 27 pages, 5 figures (degraded to reduce space). Figures 1 and 2 are multiple page figures (i.e. Fig 1a,b and Fig2a-g

An Optimal Design for Universal Multiport Interferometers

Universal multiport interferometers, which can be programmed to implement any linear transformation between multiple channels, are emerging as a powerful tool for both classical and quantum photonics. These interferometers are typically composed of a regular mesh of beam splitters and phase shifters, allowing for straightforward fabrication using integrated photonic architectures and ready scalability. The current, standard design for universal multiport interferometers is based on work by Reck et al (Phys. Rev. Lett. 73, 58, 1994). We demonstrate a new design for universal multiport interferometers based on an alternative arrangement of beam splitters and phase shifters, which outperforms that by Reck et al. Our design occupies half the physical footprint of the Reck design and is significantly more robust to optical losses.Comment: 8 pages, 4 figure

A review of malaria epidemiology and control in Papua New Guinea 1900 to 2021: progress made and future directions

The research and control of malaria has a long history in Papua New Guinea, sometimes resulting in substantial changes to the distribution of infection and transmission dynamics in the country. There have been four major periods of malaria control in PNG, with the current control programme having commenced in 2004. Each previous control programme was successful in reducing malaria burden in the country, but multiple factors led to programme failures and eventual breakdown. A comprehensive review of the literature dating from 1900 to 2021 was undertaken to summarize control strategies, epidemiology, vector ecology and environmental drivers of malaria transmission in PNG. Evaluations of historical control programs reveal poor planning and communication, and di culty in sustaining financial investment once malaria burden had decreased as common themes in the breakdown of previous programs. Success of current and future malaria control programs in PNG is contingent on adequate planning and management of control programs, effective communication and engagement with at-risk populations, and cohesive targeted approaches to sub-national and national control and elimination

Gaussian Optical Ising Machines

It has recently been shown that optical parametric oscillator (OPO) Ising machines, consisting of coupled optical pulses circulating in a cavity with parametric gain, can be used to probabilistically find low-energy states of Ising spin systems. In this work, we study optical Ising machines that operate under simplified Gaussian dynamics. We show that these dynamics are sufficient for reaching probabilities of success comparable to previous work. Based on this result, we propose modified optical Ising machines with simpler designs that do not use parametric gain yet achieve similar performance, thus suggesting a route to building much larger systems.Comment: 6 page

Diffusion Monte Carlo study of two-dimensional liquid 4^4He

The ground-state properties of two-dimensional liquid $^4$He at zero temperature are studied by means of a quadratic diffusion Monte Carlo method. As interatomic potential we use a revised version of the HFDHE2 Aziz potential which is expected to give a better description of the interaction between helium atoms. The equation of state is determined with great accuracy over a wide range of densities in the liquid phase from the spinodal point up to the freezing density. The spinodal decomposition density is estimated and other properties of the liquid, such as radial distribution function, static form factor, momentum distribution and density dependence of the condensate fraction are all presented.Comment: 19 pages, RevTex 3.0, 7 figures available upon reques