Modelling economies in transition: an introduction

This paper considers the implications of structural breaks, such as have occurred in many transition economies, for econometric modelling based on the multivariate cointegration paradigm. It outlines recent developments on the identification of linear cointegrated systems, discusses some practical problems, and presents an extension to non-linear systems. This is followed by a discussion of the impact of structural breaks on the identification and estimation of such systems. Finally, it relates these issues to the other papers in this volume.

The influence of an oil recycler on emissions with oil age for a refuse truck using in service testing

A method of cleaning lubricating oil on line was investigated using a fine bypass particulate filter followed by an infra red heater. Two bypass filter sizes of 6 and 1 micron were investigated, both filter sizes were effective but the one micron filter had the greatest benefit. This was tested on two nominally identical EURO 1 emissions compliance refuse trucks, fitted with Perkins Phazer 210Ti 6 litre turbocharged intercooled engines and coded as RT320 and RT321. These vehicles had emissions characteristics that were significantly different, in spite of their similar age and total mileage. RT321 showed an apparent heavier black smoke than RT320. Comparison was made with the emissions on the same vehicles and engines with and without the on-line bypass oil recycler. Engine exhaust emissions were measured about every 400 miles. Both vehicles started the test with an oil drain and fresh lubricating oil. The two refuse trucks were tested in a different sequence, the RT320 without the recycler fitted and then fitted later and the RT321 with the recycler fitted and then removed later in the test and both without any oil change. The RT320 was also the one with the finer bypass filter. The test mileage was nearly 8,000 miles both trucks. The air/fuel ratio was worked out by the exhaust gas analysis. The correlation between air/fuel ratio and emission parameters was determined and appropriate corrections were made in the case of that the air/fuel ratio had an effect on emissions. The results showed that the on line oil recycler cleaning system can reduce the rate of increase of the NOx with oil age. There appeared little influence of the oil recycler on carbon monoxide and hydrocarbon emissions. The rate of increase in particulate emissions was reduced by 50% for RT320 and an immediate decrease in particulate emissions was seen on RT320 test after fitting the recycler. The black smoke was reduced by 30% for RT320 in terms average value and an immediate decrease in smoke after fitting the recycler on RT320 test and an immediate increase in smoke after the removal of the recycler on RT321 test were shown

Effects of an on line bypass oil recycler on emissions with oil age for a bus using in service testing

A method of cleaning lubricating oil on line was investigated using a fine bypass particulate filter followed by an infra red heater. Two bypass filter sizes of 6 and 1 micron were investigated, both filter sizes were effective but the one micron filter had the greatest benefit. This was tested on two nominally identical EURO 2 emissions compliance single decker buses, fitted with Cummins 6 cylinder 8.3 litre turbocharged intercooled engines and coded as Bus 4063 and 4070. These vehicles had emissions characteristics that were significantly different, in spite of their similar age and total mileage. Bus 4063 showed an apparent deterioration on emissions with time while Bus 4070 showed a stabilised trend on emissions with time for their baseline tests without the recycler fitted. Comparison was made with the emissions on the same vehicles and engines with and without the on-line bypass oil recycler. Engine exhaust emissions were measured about every 2000 miles. All tests started with an oil drain and fresh lubricating oil. The two buses were tested in a different sequence, Bus 4063 with the recycler fitted and then removed later in the test after an oil change and Bus 4070 with no recycler fitted at first and then fitted after 29,000 miles with no oil change. The Bus 4070 was also the one with the finer bypass filter. The test mileage was 45,000 miles for Bus 4063 and 48,000 miles for Bus 4070. The air/fuel ratio was worked out by the exhaust gas analysis. The correlation between air/fuel ratio and emission parameters was determined. The results showed that the on line oil recycler cleaning system reduced the rate of increase of the NOx from 5% to 1.6% for Bus 4063 and from 4.1% to 0% for Bus 4070 per 10,000 miles. Hydrocarbon emissions increased 30 ppm per 10,000 miles with the recycler removed compared to a stabilised level with the recycler fitted for Bus 4063. There was a small decrease in hydrocarbon emissions after fitting the recycler for Bus 4070. The particulate emissions were reduced by 35% for Bus 4063 and 24% for Bus 4070 on average. The reductions on total particulate mass were due to reductions on particulate carbon and lube oil VOF emissions. The black smoke was reduced by 56% for Bus 4063 in terms of rate of increase and 40% for Bus 4070 in terms of average value

Corporate control and multiple large shareholders

Many firms have more than one blockholder, but finance theory suggests that one blockholder should be sufficient to bestow all benefits on a firm that arise from concentrated ownership. This paper identifies a reason why more blockholders may arise endogenously. We consider a setting where multiple shareholders have endogenous conflicts of interest depending on the size of their stake. Such conflicts arise because larger shareholders tend to be less well diversified and would therefore prefer the firm to pursue more conservative investment policies. When the investment policy is determined by a shareholder vote, a single blockholder may be able to choose an investment policy that is far away from the dispersed shareholders' preferred policy. Anticipating this outcome reduces the price at which shares trade. A second blockholder (or more) can mitigate the conflict by shifting the voting outcome more towards the dispersed shareholders' preferred investment policy and this raises the share price. The paper derives conditions under which there are blockholder equilibria.The model shows how different ownership structures affect firm value and the degree of underpricing in an IPO

Second order analysis of geometric functionals of Boolean models

This paper presents asymptotic covariance formulae and central limit theorems for geometric functionals, including volume, surface area, and all Minkowski functionals and translation invariant Minkowski tensors as prominent examples, of stationary Boolean models. Special focus is put on the anisotropic case. In the (anisotropic) example of aligned rectangles, we provide explicit analytic formulae and compare them with simulation results. We discuss which information about the grain distribution second moments add to the mean values.Comment: Chapter of the forthcoming book "Tensor Valuations and their Applications in Stochastic Geometry and Imaging" in Lecture Notes in Mathematics edited by Markus Kiderlen and Eva B. Vedel Jensen. (The second version mainly resolves minor LaTeX problems.

Iordanskii Force and the Gravitational Aharonov-Bohm effect for a Moving Vortex

I discuss the scattering of phonons by a vortex moving with respect to a superfluid condensate. This allows us to test the compatibility of the scattering-theory derivation of the Iordanskii force with the galilean invariance of the underlying fluid dynamics. In order to obtain the correct result we must retain $O(v_s^2)$ terms in the sound-wave equation, and this reinforces the interpretation, due to Volovik, of the Iordanskii force as an analogue of the gravitational Bohm-Aharonov effect.Comment: 20 pages, LaTe

Birefringence of interferential mirrors at normal incidence Experimental and computational study

In this paper we present a review of the existing data on interferential mirror birefringence. We also report new measurements of two sets of mirrors that confirm that mirror phase retardation per reflection decreases when mirror reflectivity increases. We finally developed a computational code to calculate the expected phase retardation per reflection as a function of the total number of layers constituting the mirror. Different cases have been studied and we have compared computational results with the trend of the experimental data. Our study indicates that the origin of the mirror intrinsic birefringence can be ascribed to the reflecting layers close to the substrate.Comment: To be published in Applied Physics

Rhyolitic tephra horizons in northwestern Europe and Iceland from the AD 700s-800s: a potential alternative for dating first human impact

The distribution and geochemistry of four rhyolitic tephra horizons from Iceland dated to the ad 700s–800s is assessed. These include the rhyolitic phase of the Landnám tephra (ad 870s), the ad 860 layer, a previously unrecorded tephra called the GA4–85 layer (c. ad 700–800) and the Tjïrnuvík tephra (c. ad 800s). The ad 860 and GA4–85 layers were first found in peat bogs in north Ireland. They are here correlated with equivalent horizons on Iceland which were found below the Landnám tephra (c. ad 870s). This time period is considered important in the North Atlantic region, because it coincides with a phase of human settlement in Iceland and the Faroe Islands. The establishment of a detailed tephrochronology may provide a tool for exact dating of sediment successions and sediments associated with archaeological excavations. Caution must be taken especially on Iceland where the Landnám tephra is often used for dating archaeological sites. This investigation show that several rhyolitic tephra horizons occur close in time to the Landnám tephra, and that mistakes can be made if detailed geochemical analyses are not carried out, especially in areas which are distal to the source of the Landnám tephra (the Veidivötn and Torfajökull volcanic systems, southern Iceland)

Generation of vortices and observation of Quantum Turbulence in an oscillating Bose-Einstein Condensate

We report on the experimental observation of vortex formation and production of tangled vortex distribution in an atomic BEC of Rb-87 atoms submitted to an external oscillatory perturbation. The oscillatory perturbations start by exciting quadrupolar and scissors modes of the condensate. Then regular vortices are observed finally evolving to a vortex tangle configuration. The vortex tangle is a signature of the presence of a turbulent regime in the cloud. We also show that this turbulent cloud has suppression of the aspect ratio inversion typically observed in quantum degenerate bosonic gases during free expansion.Comment: to appear in JLTP - QFS 200

Measurement of Pion Enhancement at Low Transverse Momentum and of the Delta-Resonance Abundance in Si-Nucleus Collisions at AGS Energy

We present measurements of the pion transverse momentum (p_t) spectra in central Si-nucleus collisions in the rapidity range 2.0<y<5.0 for p_t down to and including p_t=0. The data exhibit an enhanced pion yield at low p_t compared to what is expected for a purely thermal spectral shape. This enhancement is used to determine the Delta-resonance abundance at freeze-out. The results are consistent with a direct measurement of the Delta-resonance yield by reconstruction of proton-pion pairs and imply a temperature of the system at freeze-out close to 140 MeV.Comment: 12 pages + 4 figures (uuencoded at end-of-file