The Formation and Properties of Diphenyl Sulphide and Some of Its Derivatives

The therapeutic value of the diaryl sulphides has been a subject of much recent investigation. The halogen derivatives, especially iodine, or diphenyl-sulphide, have been carefully studied. The purpose of this work is not to study the therapeutic value of the diaryl sulphides, but to study some of the methods of preparation, and to determine the physical constants of a few of the compounds. Further, to study the relationship that exists between the diphenyl sulphides and the diphenyl ethers will be a part of this task

Using a Visual Routine to Model the Computation of Positional Relationships

Modeling the encoding of visual stimuli is a complex, and often ignored, problem in computational models of visual and spatial problem solving. This paper outlines a toolkit for exploring encoding for two-dimensional visual scenes, Visual Routines for Sketches. The utility of this approach is shown by a new model for computing positional relationships, the Vector Symmetry model, that explains data from seven experiments and is more parsimonious than Regier & Carlson’s (2001) AVS model

Anticrossings in Foerster Coupled Quantum Dots

We consider two coupled generic quantum dots, each modelled by a simple potential which allows the derivation of an analytical expression for the inter-dot Foerster coupling, in the dipole-dipole approximation. We investigate the energy level behaviour of this coupled two-dot system under the influence of an external applied electric field and predict the presence of anticrossings in the optical spectra due to the Foerster interaction.Comment: 13 pages, 7 figures. Published version. Substantially revised, new sections on decay rates, absorption spectra, and tunnelin

The social value of carbon sequestered in Great Britain's woodlands

One tactic for mitigating climate change associated with human-origin CO2 releases is to promote C storage in biomass, particularly trees. The economic value of C storage associated with woodland can be compared to the costs (or benefits) of other strategies for mitigating climate change. Models were developed to calculate the rates of marginal carbon storage (or release) associated with live trees, forest floor litter, soils, wood products, harvest, fossil fuel used in manufacturing and C displacement from bio-fuels and products for representative British plantation species: Sitka spruce (Picea Sitchensis) and beech (Fagus sylvatica). Map databases of public and privately-owned woodlands were compiled for Great Britain. Marginal carbon gains (or losses) were determined for each woodland in the datasets. C flux was monetised using candidate parameters for the social discount rate (1, 3, 3.5 or 5%) and social value of carbon (US$109.5,$1, $10 or$17.10/metric tonne). A conventional discount function was applied. Final results were expressed as Net Present Values, base year 2001. The modelling suggests that the minimum NPV (assuming discount rate=3% and social value of carbon = $1) of carbon sequestering in GB woodlands existing in 2001 was$82 million, with a expected further $72 million that might be added by subsequent afforestation. These figures rise dramatically if a discount rate of 1$109.5/tonne are assumed. The total value of C stored in British woodland depends very much on the assumptions about appropriate discount rate and social value of sequestered carbon

Stock assessment of Australian east coast sea mullet (Mugil cephalus) with data to December 2020

Australian east coast sea mullet (Mugil cephalus) are a predominantly commercially caught species. Sea mullet occur as one continuous stock (population) off the Australian east coast. This is the third stock assessment of the Australian east coast stock. The assessment implemented a two-sex population model fit to age and length data, constructed within the Stock Synthesis modelling framework. The model incorporated data spanning the period 1899 to 2020 including commercial harvests (1899–2020), and length and age data (1990–2020). Eight model scenarios were run, covering a range of modelling assumptions. Base case (preferred) scenario results suggested that biomass has shown an overall decline since 1980 to 37% unfished biomass in 2021 (31–43% range across scenarios). The harvest consistent with a biomass ratio of 50%, the Harvest Strategy target, was estimated at 4801 t (4357–5054 t range across scenarios). The recommended harvest in 2021 for all regions is 2541 t (1254–3632 t range across scenarios) to return to 50%

Modelling environmental equity: Exposure to environmental urban noise pollution in Birmingham, UK

This paper examines the extent to which inequalities in noise exposure are present in the city of Birmingham in the English midlands. Estimates of road and rail noise levels were made using established sound propagation models and were combined with data on noise generated from the city's airport. Demographic details from the 1991 UK Census provided information on population age, ethic makeup, and deprivation. No relationship was established between noise exposure and population age, and there was only rather weak evidence of an association between noise exposure and ethnicity. However, greater disparities were observed in estimated noise exposures and levels of socio-economic deprivation. The implications of these findings with regard to possible efforts to reduce urban noise levels are discussed

Creating excitonic entanglement in quantum dots through the optical Stark effect

We show that two initially non-resonant quantum dots may be brought into resonance by the application of a single detuned laser. This allows for control of the inter-dot interactions and the generation of highly entangled excitonic states on the picosecond timescale. Along with arbitrary single qubit manipulations, this system would be sufficient for the demonstration of a prototype excitonic quantum computer.Comment: 4 pages, 3 figures; published version, figure 3 improved, corrections to RWA derive

Transferring multivariate benefit functions using geographical information systems

Recreation value studies have to date generally failed to adequately transfer functions predicting visitor numbers and benefit values from 'source' to 'target' recreational sites. One reason behind such failure may lie in the difficulty of successfully modelling the inter-site variation in predictors. The present study employs a geographical information system (GIS) to tackle this issue by integrating data from a number of sources (including a recreational site survey, the national census, regional road networks, etc.) permitting improved and standardised measurement and analysis of predictors at both source and target sites. The paper applies Poisson regression techniques to a set of GIS derived explanatory variables predicting arrivals and consumer surplus estimates at a single target woodland recreation site. GIS techniques are then used to define a corresponding set of predictors at 30 other target woodland recreation sites across England for which actual arrival numbers were known. Comparison of actual versus predicted arrivals provided a test of transferral validity which proved satisfactory and consumer surplus estimates were derived as before