Ground state correlations in a trapped quasi one-dimensional Bose Gas

We review the basic concepts of a non-equilibrium kinetic theory of a trapped bosonic gas. By extending the successful mean-field concept of the Gross-Pitaevskii equation with the effects of non-local, two particle quantum correlations, one obtains a renormalized binary interaction and allows for the dynamic establishment of non-classical many-particle quantum correlations. These concepts are illustrated by self-consistent numerical calculations of the first and second order ground state quantum correlations of a harmonically trapped, quasi one-dimensional bosonic gas. We do find a strong suppression of the density fluctuations or, in other words, an enhanced number squeezing with decreasing particle density.Comment: 19 pages LaTeX, 19 color figures, to be published in the special issue on "Degenerate Quantum Gases" in Opt. Com. (2004

Role of Copper and Tor Signaling in Reactive Oxygen Species Induced Cell Aging

Chronological lifespan assays in yeast rely on promoting a culture’s quiescent stationary phase by calorie restriction, a phase characterized by curtailed overall metabolic rate and a shift from fermentation to mitochondrial respiration. This shift in glucose utilization can be accomplished by reduced TOR (Target of Rapamycin) pathway signaling, a complex regulator of cell growth and cell cycle in which various environmental growth and nutrient signals are integrated to activate or inhibit the Ser/Thr kinase activity of Tor1 protein. Optimal growth conditions promote TOR signaling causing macromolecule biosynthesis, sugar fermentation, increased metabolism, and progression through cell cycle. Many downstream effects of TOR signaling can be silenced by cell treatment with Rapamycin, a drug which binds to Tor1 and inhibits kinase domain function, drastically increasing a cell culture’s chronological lifespan. Mitochondrial electron transport chain (ETC) machinery, whose activity and expression is modulated by TOR signaling, is the primary site of superoxide formation. Superoxide is a reactive oxygen species (ROS) produced by premature electron leakage directly to oxygen, producing dangerous hydroxyl radicals, via the Haber-Weiss reaction, that diffuse throughout the cell causing damage to DNA, lipid peroxidation, and mitochondrial dysfunction associated with premature cell aging and death most prevalent in neuronal tissue afflicted with neurodegenerative disease. A primary defense of free radical damage as a respiratory by-product is the neutralization of superoxide by superoxide dismutase 1 (SOD1), which requires copper and zinc as cofactors in the conversion of superoxide to less harmful hydrogen peroxide. Copper is additionally utilized in cytochrome c oxidase as an electron transferring group and is required for the continuous movement of high energy electrons through the ETC, thereby limiting the potential for electron leakage and ROS. Copper, given its two roles in defending against ROS production and induced cell aging, is here modulated by extracellular supplementation to further elucidate its functionality in the context of possible lifespan extension by Rapamycin treatment of SOD1 deletion strains

New Ways through the Alps The New Gotthard Base Tunnel - Impact of a Big Construction Site on a Small Mountain Village

For Switzerland as located in the heart of Europe transport policy is a matter of particular importance. Especially transports between Italy and Germany use the Swiss corridors through the Alps. Therefore Switzerland realised a most ambitious construction project called NEAT (Neue Alpen Transversale) to improve the European train connections especially for freight transports. One part of the project is the new Gotthard base tunnel, the longest railway tunnel of the world and the most impressive element of the new transalpine railway line through the Alps. In view of the difficult accessibility and extreme climatic conditions, ensuring the fast and reliable transit of more than 300 trains per day through the two 57 km long single-track galleries represents a considerable technical challenge. The Gotthard base line directly links the northern and southern sides of the Alps and the project of building a new line should achieve the following goals: Massive increase in goods capacity (twice as much as today) Much shorter North-South transit time for passengers and freight Reduced traction power requirements, per weight unit of transported goods, as a result of the elimination of steep slopes. The construction work started in 1996 and will be probably finished by 2013. Because of the length of the tunnel five points were chosen, from which the drilling started. The shortest but technical most challenging phase of construction is located under the small village of “Sedrun” in the canton of “Graubünden”. Sedrun is a tourism destination for skiing, 1335 m above sea level with about 1.500 inhabitants. Here a gallery leads to a mine shaft with a depth of 800 m, ending at 550 m above sea level. At the intermediate access of Sedrun a multifunctional station is located which also is used for crossover, air ventilation, technical infrastructure and in case of emergency. The construction site with its enormous needs on resources, infrastructure, workforces - for example at the beginning a lot of specialists from South African mining branch came to Sedrun – may be a big challenge for the small village. In 2004 during the peak period up to 400 workers have been employed. Also logistical solutions for the transport of machines and material to the construction side and the carrying of stone to the deposits have to be developed. An ongoing long-term accompanying research (2000 – 2013) is analysing the ecological, economic and social impact on the construction site for the village and the region. The research project wants to assess the sustainability of such a long-term construction process. The contracting body is an advisory group of public institutions including the community of Sedrun, the region ‘Obere Surselva’, the canton Graubünden and the Swiss Federal Office of Transport. Within the long-term research a set of indicators will be collected every year furthermore an every third year deep-rooted analysis on different topics will be done. The project also has the function of an early-warning system to anticipate unexpected stresses and strains. The results of the research will be visualised from a documentary film team. Besides the annual research we tried to answer the following question: Which are the economic impacts of the construction site for the region of Sedrun? The decision to choose Sedrun as one of the five construction sites for the Gotthard base tunnel did not only change the ecological and social situation in the region but also has economic effects on the community. Especially the local building sector but also hotels, restaurants and local industry are benefiting from the construction site. To calculate these economic effects for the region of Sedrun we used the method of the incidence analysis. The incidence analysis is a kind of cost-benefit analysis which is especially suited to assess the spatial effects of infrastructural facilities or the service of these facilities. Considering the direct effects we focus on the receipts and expenditures which are directly connected with the realisation of the project. The economic effects could be divided into the so called tangible and intangible effects. Tangible effects are measurable as indirect economic effects (spill-over effects). To measure the indirect economic effects we carry out an interview survey among the workers to calculate the additional economic impacts caused by the expenditures of the workers in the region. The intangible effects could be explained as soft and mostly not quantifiable effects. To acquire the intangible effects we carry out an image analysis based on national newspaper articles about the construction site in Sedrun. In our paper we present the structure and main indicators of the long-term accompanying research and the results of the incidence analysis to calculate the economic effects for the region.

Raman velocity filter as a tool for collinear laser spectroscopy

The velocity distribution of a hot ionic beam can be filtered with a narrow stimulated Raman process to prepare a colder subensemble, as substantiated in this theoretical analysis. Using two counter-propagating, far-detuned lasers, we can define a $\pi$-pulse for the resonant velocity to transfer atoms within the linewidth of the Raman resonance between the ground-states of a $\Lambda$-system. Spontaneous emission from the two single-photon resonances, as well as the ground-state decoherence induced by laser noise, diminishes the efficiency of the filter. From a comprehensive master equation, we obtain conditions for the optimal frequency pair of the lasers and evaluate the filter performance numerically, as well as analytically. If we apply this analysis to current $^{40}$Ca$^+$ ion experiments, we obtain a sensitivity for measuring high ion acceleration voltages on the ppm level or below.Comment: Corrected typos. Corrected: Missing minus in Eq. 35. Improved readability by including a few repetitions of quantity definitions and improved display of relevant quantities in Table II of the Appendi

Reversible and irreversible evolution of a condensed bosonic gas

We have formulated a kinetic theory for a condensed atomic gas in a trap, i.e., a generalized Gross-Pitaevskii equation, as well as a quantum-Boltzmann equation for the normal and anomalous fluctuations [R. Walser et al., Phys. Rev. A, 59, 3878 (1999)]. In this article, the theory is applied to the case of an isotropic configuration and we present numerical and analytical results for the reversible real-time propagation, as well as irreversible evolution towards equilibrium.Comment: 15 pages RevTeX, 8 figures, reviewed PRA resubmissio

Optimal pulse propagation in an inhomogeneously gas-filled hollow-core fiber

We study optical pulse propagation through a hollow-core fiber filled with a radially inhomogeneous cloud of cold atoms. A co-propagating control field establishes electromagnetically induced transparency. In analogy to a graded index fiber, the pulse experiences micro-lensing and the transmission spectrum becomes distorted. Based on a two-layer model of the complex index of refraction, we can analytically understand the cause of the aberration, which is corroborated by numerical simulations for a radial Gaussian-shaped function. With these insights, we show that the spectral distortions can be rectified by choosing an optimal detuning from one-photon resonance.Comment: 15 pages, 8 figures, typos corrected, references added, figure style slightly modified, Comment on Faraday rotation added between Eq. (21) and (22

Quo vadis? How to measure the quality of local and regional development processes?

Today most activities which seem to be sound, cosy and helpful - or sometimes simply useful - are called ?sustainable'. Of course the requirements for measuring sustainability increased rapidly. Many different systems of indicators and conflicting opinions about the adequate approach characterise the present situation. Nevertheless we add another system with an specific approach to evaluate processes of local and regional development. In our opinion it is able notably to refer to the quality of the concept of sustainability. The basic system is threefold and bears analogy to the model of total quality management. We distinguish between: · The assessment of projects with respect to material, procedural and ethical implications. The conceptual framework is translated into an evaluation checklist to systematise the discussion of the character and general impact of a given project or programme. The methodology of this section has been presented at the 39th ERSA Congress 1999 in Dublin even and until now has been applied in different fields. · The assessment of development processes in terms of organisation, methodology, contents and legal demands. This section will be the main part of our presentation. · And the assessment of the state of the region which actually is a 'work in progress'. It will combine elements of 'top-down indicators, deduced from the international and national discussion of the CSD-scheme, with elements of regional specific indicators based on a bottom-up approach which defines regional specific goals of development according to a transdisciplinary approach of how to experience the local and regional space. Our methodology is based on self-evaluation and it can come into operation at an early stage accompanying the activities over the whole life cycle. The assessment of development processes is to be done from the local and regional actors for themselves, accompanied by scientific experts. It depends on four principles: · The people concerned are the experts. They get involved in learning processes. · The focus of the assessment is on credibility and transparency. · Development processes need a minimum of quality. The standard is fixed. · The quality management can be used in a flexible way to allow the assessment of different processes according to the communities main focus. The whole project of quality management is closely coupled with the regional Agenda 21 in the Lake of Constance- region as it has been shown eat the 40th ERSA Congress 2000 in Barcelona. Together with the network of 13 regional contact points in Switzerland, Austria, Germany and the Principality of Liechtenstein the different sections has been discussed and field-tested. 437 words Key words: sustainability, Agenda 21, quality management, development processes, transdisciplinarity