New Results on Ultrafast Coherent Excitation of Molecular Vibrations in Liquids

Coherent Raman probe scattering experiments are performed to study dynamical processes of polyatomic liquids at 300 K. For single homogeneous transitions the dephasing timeT 2 is readily obtained from time resolved investigations. Spectral studies show an interesting time dependent shift in scattered frequency. After the excitaiton the vibrating molecules are shown to relax freely with their resonance frequency. Multiple, equally spaced transitions exhibit a beating phenomenon which provides the dephasing time and the frequency interval between neighboring vibrational states. Inhomogeneously broadened systems do not allow a ready determination of the dephasing time by the present probing technique. Previous experiments on the subject have to be reconsidered

Investigations of Free Turbulent Mixing

A discussion of the integral relations for the flow of the boundary-layer type is presented. It is shown that the characteristic laws of spread of jets, wakes, and so forth, can be obtained directly for the laminar case and, with the help of dimensional reasoning, for the turbulent case as well. Measurements of the mean velocity, the intensity and scale of the turbulent fluctuations, and of the turbulent shear in a two-dimensional mixing zone are presented. The results of these measurements are compared with the mixing-length theories. It is shown that both mixing length and exchange coefficient vary across the mixing zone. The theories based on the assumption of constant mixing length or exchange coefficient are thus in error. A discussion of the energy balance of the fluctuating motion is given and the triple point correlation is estimated

Settlement Patterns on the Swedish Countryside in the Emerging Knowledge Society

As in other countries, urbanization and industrialization in Sweden was two sides of the same coin. To a large extent, the Swedish urbanization took place at a low level with the emergence of many small towns. The last decades, a redistribution of the urban population to bigger cities has happened. Simultaneously, the real countryside has increased its population around the big and mid-sized cities within commuting distance, but the countryside has also increased its share of the population in a majority of municipalities. Westlund (2002) found that the countryside’s population growth 1990-97 primarily could be explained by income and the size of the local labor market. In this paper, we examine the current trends of population development and extend the possible explanatory variables to among others, some variables measuring local social capital.

Social Union, Convergence and Migration

The forces of the market and systems competition bring about economic and social convergence in Europe, and there is no need for social policies at the EU level. Social harmonization would distort migration flows and slow down the speed of economic convergence. National welfare states will be threatened by the free migration of people in Europe. The race to the bottom is a serious risk. However, to contain this risk, neither harmonization of welfare payments nor constraints on migration are needed. The adoption of the principle of selectively delayed integration is a better alternative.

Observation of a bacteriochlorophyll anion radical during the primary charge separation in a reaction center

The primary light-induced charge separation in reaction centers of Rhodobacter sphaeroides was investigated with femtosecond time resolution. The absorption changes in the time range 100 fs to 1 ns observed after direct excitation of the primary donor P at 860 nm could only be explained by a kinetic model which uses three time constants. This finding supports the following reaction scheme: (i) the electronically excited primary donor P* decays with a time constant of 3.5 ps and populates a very short-lived intermediate involving a reduced accessory bacteriochlorophyll molecule; (ii) with a time constant of 0.9 ps the electron is transferred to the neighboring bacteriopheophytin molecule; and (iii) from there within 200 ps to the quinone

Social Union, Convergence and Migration

The forces of the market and systems competition bring about economic and social convergence in Europe. There is no need for social policies at the EU level. Social harmonisation would distort migration flows and slow down the speed of economic convergence. National welfare states will be threatened by the free migration of people in Europe. The race to the bottom is a serious risk. However, to contain this risk, neither harmonisation of welfare payments nor constraints on migration are needed. The adoption of the principle of selectively delayed integration is the better alternative.