The Impact of Milk Quota Abolishment on Dutch Agriculture and Economy: Applying an Agricultural Sector Model Integrated Into a Mixed Input-Output Model

A modelling system is presented and used to analyse the impact of milk quota abolishment on Dutch agriculture and economy. The modelling system consists of a regionalised, agri-environmental, partial equilibrium, mathematical programming model of agriculture supply in the Netherlands integrated into a mixed input-output model. It was found that abolition of the milk quota system has large impacts on milk production and livestock numbers and composition. The latter is explained by the strict mineral and manure policies in the Netherlands; an increase in the numbers of dairy cows leaves less room for other livestock. It is also found that, although the total effect on gross value added in the Dutch economy is limited, the effects for individual industries can be large.Mathematical programming, Manure markets, Input-Output, Dairy policy, Agribusiness,

Oral Cancer in Malta

The incidence of oral cancer is influenced by a variety of recognized contributory factors. A proportion of these factors are national habits. As a consequence the Incidence varies enormously from country to country and between different racial groups in the same country. This study, covering a four year period 1969-1972, was undertaken with a view to putting into perspective the problem of oral cancer in Malta. Oral cancer accounts for 6.2% of the total number of malignancies. This can be regarded as a relatively low percentage. A wide range of figures is reported from other countries varying between 5% and 50%. In Malta cancer of the lip is seen to account for the majority of oral tumours 55.9%. The incidence of oral malignancies is commoner in males than in females although cancer of the tongue is not uncommon in females. The relatively high incidence per 100,000 population of cancer of the lip gives cause for concern. This is no doubt due, in part, to the high level of actinic rays in the island.peer-reviewe

Atom Lasers, Coherent States, and Coherence:II. Maximally Robust Ensembles of Pure States

As discussed in Wiseman and Vaccaro [quant-ph/9906125], the stationary state of an optical or atom laser far above threshold is a mixture of coherent field states with random phase, or, equivalently, a Poissonian mixture of number states. We are interested in which, if either, of these descriptions of $\rho_{ss}$, is more natural. In the preceding paper we concentrated upon whether descriptions such as these are physically realizable (PR). In this paper we investigate another relevant aspect of these ensembles, their robustness. A robust ensemble is one for which the pure states that comprise it survive relatively unchanged for a long time under the system evolution. We determine numerically the most robust ensembles as a function of the parameters in the laser model: the self-energy $\chi$ of the bosons in the laser mode, and the excess phase noise $\nu$. We find that these most robust ensembles are PR ensembles, or similar to PR ensembles, for all values of these parameters. In the ideal laser limit ($\nu=\chi=0$), the most robust states are coherent states. As the phase noise $\nu$ or phase dispersion $\chi$ is increased, the most robust states become increasingly amplitude-squeezed. We find scaling laws for these states. As the phase diffusion or dispersion becomes so large that the laser output is no longer quantum coherent, the most robust states become so squeezed that they cease to have a well-defined coherent amplitude. That is, the quantum coherence of the laser output is manifest in the most robust PR states having a well-defined coherent amplitude. This lends support to the idea that robust PR ensembles are the most natural description of the state of the laser mode. It also has interesting implications for atom lasers in particular, for which phase dispersion due to self-interactions is expected to be large.Comment: 16 pages, 9 figures included. To be published in Phys. Rev. A, as Part II of a two-part paper. The original version of quant-ph/9906125 is shortly to be replaced by a new version which is Part I of the two-part paper. This paper (Part II) also contains some material from the original version of quant-ph/990612

A thin ring model for the OH megamaser in IIIZw35

We present a model for the OH megamaser emission in the starburst galaxy IIIZw35. The observed diffuse and compact OH maser components in this source are explained by a single phase of unsaturated clumpy gas distributed in a thin ring structure and amplifying background continuum. We emphasize the importance of clumpiness in the OH masing medium, an effect that has not been fully appreciated previously. The model explains why multiple bright spots are seen only at the ring tangents while smoother emission is found elsewhere. Both the observed velocity gradients and the line to continuum ratios around the ring enquire a geometry where most of the seed photons come from a continuum emission which lies outside the OH ring. To explain both the OH and continuum brightness, free-free absorbing gas is required along the ring axis to partially absorb the far side of the ring. It is proposed that the required geometry arises from an inwardly propagating ring of starburst activity

Removal of a single photon by adaptive absorption

We present a method to remove, using only linear optics, exactly one photon from a field-mode. This is achieved by putting the system in contact with an absorbing environment which is under continuous monitoring. A feedback mechanism then decouples the system from the environment as soon as the first photon is absorbed. We propose a possible scheme to implement this process and provide the theoretical tools to describe it

Is international emissions trading always beneficial?

Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).Economic efficiency is a major argument for the inclusion of an international emission permit trading system under the Kyoto Protocol. Using a partial equilibrium framework, energy system models have shown that implementing tradable permits for greenhouse gases internationally could reduce compliance costs associated with the emission targets. However, we show that international emission trading could be welfare decreasing under a general equilibrium framework. We describe a case of immiserizing growth in the sense of Bhagwati where the negative terms of trade and tax-interaction effects wipeout the primary income gains from emission trading. Immiserizing emission trading occurs only when there are pre-existing distortions in the economy. Simulation results based on a CGE model developed at MIT (the EPPA model) show that under an EU-wide emission trading regime the introduction of a permit trading system cause welfare losses for some of the trading countries

Traditional Chinese Herbal Medicine – East Meets West in Validation and Therapeutic Application

Author name used in this publication: Sonny H. M. Tse2011-2012 > Academic research: refereed > Chapter in an edited book (author)published_fina

Spectral line and continuum radiation propagation in a clumpy medium

We discuss the propagation of spectral line and continuum radiation in a clumpy medium and give general expressions for the observed absorption or emission from a cloud population. We show that the affect of the medium clumpiness can usually be characterised by a single number multiplying the mean column opacity. Our result provides a simpler proof and generalisation of the result of Martin et al (1984). The formalism provides a simple way to understand the effects of clumping on molecular line profiles and ratios, for example how clumping effects the interpretation of 13CO(1-0) to 12CO(1-0) line ratios. It can also be used as a propagation operator in physical models of clumpy media where the incident radiation effects the spectral line emissivity. We are working to extend the formalism to the propagation of masers in a clumpy medium, but in this case there are special difficulties because formal expectation values are not characteristic of observations because they are biased by rare events.Comment: 6 pages, 1 Figure. Accepted for publication by ApSS. Proc of conference on 'Dense Molecular gas around protostars and in galactic Nuclei'. Zwolle, Netherlands, Feb 17th - 20th, 200