Working with the XQC

An enormous number of statistical methods have been developed in quantitive finance during the last decades. Nonparametric methods, bootstrapping time series, wavelets, estimation of diffusion coefficients are now almost standard in statistical applications. To implement these new methods the method developer usually uses a programming environment he is familiar with. Thus, such methods are only available for preselected software packages, but not for widely used standard software packages like MS Excel. To apply these new methods to empirical data a potential user faces a number of problems or it may even be impossible for him to use the methods without rewriting them in a different programming language. Even if one wants to apply a newly developed method to simulated data in order to understand the methodology one is confronted with the drawbacks described above. A very similar problem occurs in teaching statistics at undergraduate level. Since students usually have their preferred software and often do not have access to the same statistical software packages as their teacher, illustrating examples have to be executable with standard tools. In general, two statisticians are on either side of the distribution process of newly implemented methods, the provider (inventor) of a new technique (algorithm) and the user who wants to apply (understand) the new technique. The aim of the XploRe Quantlet client/server architecture is to bring these statisticians closer to each other. The XploRe Quantlet Client (XQC) represents the front end - the user interface (UI) of this architecture allowing to access the XploRe server and its methods and data. The XQC is fully programmed in Java not depending on a specific computer platform. It runs on Windows and Mac platforms as well as on Unix and Linux machines.XploRe Quantlet Client, quantitive finance, application, applet

"Reinventing" Vocational Education Policy: Pitfalls and Possibilities

This article traces vocational education policy in the province of Alberta from the 1960s federal Technical and Vocational Training Assistance Act to the provincial endorsement of new curriculum and transition initiatives in the 1990s. The purpose is to understand the implications of shifts in policy over time. Our examination suggests that although the current provincial approach is strengthened by the commitment of local educators and employers, it is hampered by the lack of institutional support including resources and research into outcomes, as well as coherence and clarity about educational policy objectives. The resilience of existing structures, attitudes, and practices also poses challenges to the implementation of policy.Cet article reprend l'évolution de la politique sur la formation professionnelle en Alberta, depuis la loi fédérale (Technical and Vocational Training Assistance Act) des années 1960 jusqu'aux années 1990 caractérisées par l'appui provincial aux nouveaux programmes d'études et projets de transition. Le but de l'étude est de comprendre les conséquences des changements de politique au fil du temps. La recherche des auteurs laisse croire que même si la position albertaine actuelle est renforcée par l'engagement des enseignants et des employeurs provinciaux, elle est gênée par un manque de soutien institutionnel (impliquant les ressources et la recherche sur les résultats) et un besoin de cohérence et clarté dans les objectifs d'une politique éducative. La résilience des structures, des attitudes et des pratiques existantes viennent également contrarier la mise en œuvre de politiques

Effects of remote and local atmospheric forcing on the circulation and upwelling in the Baltic Sea

Due to the ephemeral nature of the atmospheric conditions over the Baltic Sea, the flow field is highly variable, and thus, changes in the resulting circulation and upwelling are difficult to observe. However, three-dimensional models, forced by realistic atmospheric conditions and river runoff, have reached such a state of accuracy that the highly fluctuating current field and the associated evolution of the temperature and salinity field can be described. In this work, effects of remote and local atmospheric forcing on circulation and upwelling in the Baltic Sea are investigated. Changes in the characteristics of the large-scale atmospheric wind field over the central and eastern North Atlantic can be described by the North Atlantic Oscillation (NAO). The NAO is related to the strength and geographical position of weather systems as they cross the North Atlantic and thus has a direct impact on the climate in Europe. To relate the local wind field over the Baltic Sea to the large-scale atmospheric circulation, we defined a Baltic Sea Index (BSI), which is the difference of normalised sea level pressures between Oslo in Norway and Szczecin in Poland. The NAO is significantly related to the BSI. Furthermore, the BSI is highly correlated with the storage variation of the Baltic Sea and the volume exchange through the Danish Sounds. Based on three-dimensional model calculations, it is shown that different phases of the NAO during winter result in major changes of horizontal transports in the deep basins of the Baltic Sea and in upwelling along the coasts as well as in the interior of the basins. During NAO+ phases, strong Ekman currents are produced with increased up- and downwelling along the coasts and associated coastal jets, whereas during NAO− phases, Ekman drift and upwelling are strongly reduced, and the flow field can almost entirely be described by the barotropic stream function. The general nature of the mean circulation in the deep basins of the Baltic Sea, obtained from a 10-yr model run, can be described by the depth integrated vorticity balance derived from the transport equation for variable depth

Cosmological implications of the KOTO excess

The KOTO experiment has reported an excess of $K_L\to\pi^0\nu\bar\nu$ events above the standard model prediction, in tension with the Grossman--Nir bound. The GN bound heavily constrains new physics interpretations of an excess in this channel, but another possibility is that the observed events originate from a different process entirely: a decay of the form $K_L\to\pi^0X$, where $X$ denotes one or more new invisible species. We introduce a class of models to study this scenario with two light scalars playing the role of $X$, and we examine the possibility that the lighter of the two new states may also account for cosmological dark matter. We show that this species can be produced thermally in the presence of additional interactions apart from those needed to account for the KOTO excess. Conversely, in the minimal version of the model, dark matter must be produced non-thermally. In this case, avoiding overproduction imposes constraints on the structure of the low-energy theory. Moreover, this requirement carries significant implications for the scale of reheating in the early universe, generically preferring a low but observationally-permitted reheating temperature of O(10 MeV). We discuss astrophysical and terrestrial signatures that will allow further tests of this paradigm in the coming years.Comment: 43 pages, 10 figure

Binary Maps for Image Separation in Iterative Neuronal Network Applications

Generating a series of images is an important task invarious fields of scientific research, e. g. Computational fluiddynamics (CFD). In the past years, solutions based on deepneural networks gained importance. In these tasks, it’s oftennecessary to declare regions of interest in the image. Further-more, the NN should only perform on these regions and therest should be ignored. With this paper, we propose an inno-vative and easy method for implementing this behavior in thefield of CFD

UV physics from IR features: new prospects from top flavor violation

New physics in the rare top decays $t \to q \ell^+\ell^-$ is currently very weakly constrained. We show that in a large class of Standard Model extensions, existing experimental constraints on new physics in flavor-conserving processes imply strong indirect bounds on new physics contributions to flavor-violating processes of the form $t \to q \ell^+\ell^-$. These indirect bounds arise from basic principles of quantum field theory together with a few generic conditions on the UV structure of the theory, and are roughly an order of magnitude stronger than the present experimental bounds on the same processes. These constraints provide a theoretically-motivated target for experimental searches for $t \to q \ell^+\ell^-$: violation of these bounds would exclude a large class of new physics models, and would provide nontrivial insight into the UV behavior of the new physics.Comment: 16 pages, 6 figure