Exploiting the directional sensitivity of the Double Chooz near detector

In scintillator detectors, the forward displacement of the neutron in the reaction $\bar\nu_e+p\to e^++n$ provides neutrino directional information as demonstrated by the CHOOZ reactor experiment with 2,500 events. The near detector of the forthcoming Double Chooz experiment will collect $1.6\times10^5$ events per year, enough to determine the average neutrino direction with a $1 \sigma$ half-cone aperture of $2.3^\circ$ in one year. It is more difficult to separate the two Chooz reactors that are viewed at a separation angle $\phi=30^\circ$. If their strengths are known and approximately equal, the azimuthal location of each reactor is obtained with $\pm6^\circ$ ($1 \sigma$) and the probability of confusing them with a single source is less than 11%. Five year's data reduce this ``confusion probability'' to less than 0.3%, i.e., a $3 \sigma$ separation is possible. All of these numbers improve rapidly with increasing angular separation of the sources. For a setup with $\phi=90^\circ$ and one year's data, the azimuthal $1 \sigma$ uncertainty for each source decreases to $\pm3.2^\circ$. Of course, for Double Chooz the two reactor locations are known, allowing one instead to measure their individual one-year integrated power output to $\pm11$ ($1 \sigma$), and their five-year integrated output to $\pm4.8$ ($1 \sigma$).Comment: 7 pages, 10 figure

Combined effects of chemical and natural stressors on Daphnia magna in a context of global change: extrapolating from short-term experiments on individuals to long-term effects at the population level

The exponentially increasing human population and the associated rise in chemical and nutrient input through ongoing urban, industrial and agricultural activity have exerted substantial pressure on aquatic ecosystems. The research conducted in the context of this PhD dissertation is situated in the field of ecotoxicology, which is concerned with investigating how individuals, populations, communities, and ecosystems respond to chemical stress. As such, ecotoxicology underpins many important legal frameworks related to environmental protection, such as ecological risk assessment (ERA) and the setting of environmental quality standards (EQS) for chemicals. Typically, the effects of single substances have been tested by means of laboratory toxicity tests, on a few (more or less relevant) model test species. There is however a pressing need to evaluate the combined effects of stressors, as research suggests that mixtures at No-Observed-Effect-Concentration (NOEC) levels of individual substances may cause adverse effects when they are combined. With global climate change projections, co-occurrences of natural and chemical stressors are only predicted to increase. The aim of the PhD thesis was to investigate the combined effects of metals (copper and zinc) with additional stressors (harmful algal blooms and global warming) at different organization levels (individual vs. population), and time-scales (short term vs. long term) on the freshwater zooplankton Daphnia magna

Parallel Overlapping Schwarz Preconditioners for Incompressible Fluid Flow and Fluid-Structure Interaction Problems

Efficient methods for the approximation of solutions to incompressible fluid flow and fluid-structure interaction problems are presented. In particular, partial differential equations (PDEs) are derived from basic conservation principles. First, the incompressible Navier-Stokes equations for Newtonian fluids are introduced. This is followed by a consideration of solid mechanical problems. Both, the fluid equations and the equation for solid problems are then coupled and a fluid-structure interaction problem is constructed. Furthermore, a discretization by the finite element method for weak formulations of these problems is described. This spatial discretization of variables is followed by a discretization of the remaining time-dependent parts. An implementation of the discretizations and problems in a parallel C++ software environment is described. This implementation is based on the software package Trilinos. The parallel execution of a program is the essence of High Performance Computing (HPC). HPC clusters are, in general, machines with several tens of thousands of cores. The fastest current machine, as of the TOP500 list from November 2019, has over 2.4 million cores, while the largest machine possesses over 10 million cores. To achieve sufficient accuracy of the approximate solutions, a fine spatial discretization must be used. In particular, fine spatial discretizations lead to systems with large sparse matrices that have to be solved. Iterative preconditioned Krylov methods are among the most widely used and efficient solution strategies for these systems. Robust and efficient preconditioners which possess good scaling behavior for a parallel execution on several thousand cores are the main component. In this thesis, the focus is on parallel algebraic preconditioners for fluid and fluid-structure interaction problems. Therefore, monolithic overlapping Schwarz preconditioners for saddle point problems of Stokes and Navier-Stokes problems are presented. Monolithic preconditioners for incompressible fluid flow problems can significantly improve the convergence speed compared to preconditioners based on block factorizations. In order to obtain numerically scalable algorithms, coarse spaces obtained from the Generalized Dryja-Smith-Widlund (GDSW) and the Reduced dimension GDSW (RGDSW) approach are used. These coarse spaces can be constructed in an essentially algebraic way. Numerical results of the parallel implementation are presented for various incompressible fluid flow problems. Good scalability for up to 11 979 MPI ranks, which corresponds to the largest problem configuration fitting on the employed supercomputer, were achieved. A comparison of these monolithic approaches and commonly used block preconditioners with respect to time-to-solution is made. Similarly, the most efficient construction of two-level overlapping Schwarz preconditioners with GDSW and RGDSW coarse spaces for solid problems is reported. These techniques are then combined to efficiently solve fully coupled monolithic fluid-strucuture interaction problems

Biomechanical Movement Analysis Regarding the Aspect of Energy Input

Impulse for the developmental steps in Biomechanics have frequently been provided by the continuous progress in modern age sciences and technologies, too. During the last few decades a completely new and higher quality has been established in the field of kinemetry by the application of Video technology. The three-dimensional motion analysis from film pictures have been perfected in measuring procedures to a point making it almost a routine method nowadays. Laser technology brought progress for the distance-time measurements as for the transducers of values measured during dynamometric investigations in a decisive scale

Preparation and evaluation of advanced electrocatalysts for phosphoric acid fuel cells

Two cooperative phenomena are required the development of highly efficient porous electrocatalysts: (1) is an increase in the electrocatalytic activity of the catalyst particle; and (2) is the availability of that electrocatalyst particle for the electromechanical reaction. The two processes interact with each other so that improvements in the electrochemical activity must be coupled with improvements in the availability of the electrocatalyst for reaction. Cost effective and highly reactive electrocatalysts were developed. The utilization of the electrocatalyst particles in the porous electrode structures was analyzed. It is shown that a large percentage of the electrocatalyst in anode structures is not utilized. This low utilization translates directly into a noble metal cost penalty for the fuel cell

The Role of CLU1 in Maintaining Mitochondrial Genome Stability and Morphology in S. cerevisiae

Mitochondrial genome maintenance is essential for the normal function of the cell. Mitochondrial DNA (mtDNA) is located in the matrix, where it is in close proximity to the electron transport chain, which is within the inner mitochondrial membrane. During oxidative phosphorylation, the electron transport chain produces reactive oxygen species (ROS) that may damage the DNA and contribute to mutations within the genome. Mutations in the mitochondrial genome have long been hypothesized as a contributor to diseases, especially those of the neuromuscular system. Mitochondrial mutations have also been linked to some types of cancer, programmed cell death, and aging in humans. The ability to repair this damage is integral for cells to maintain proper fw1ction and longevity. S. cerevisiae is a facultative anaerobe that can grow in the absence of respiration under specific growth conditions, although mitochondria are still required for viability. The lab used a yeast two-hybrid assay with the known mitochondrial protein, Ilv5p, to isolate genes involved in the organization, repair, and recombination of mtDNA. The lab has identified the Clu1p in this screen. Clu1p function was previously found to be required for proper mitochondrial morphology and distribution (1). My thesis research has focused on creating clu1Δ strains and performing fluctuation analysis assays using different reporters that measure specific mitochondrial events. Initial characterization of CLU1 has shown that loss of Clu1p leads to an increased loss of mitochondrial function which may occur through various events, such as point mutations, recombinations or deletions, and DNA polymerase slippage. Microscopy has supported previous reports indicating that a clu1Δ strain displays a clustering phenotype (Fields et al. 1998). This deletion strain exhibits a branched mitochondrial network that is localized to one side within the yeast cell. These data provide evidence that Clu1p plays a central role in mitochondrial genome stability and morphology

RECENT FINDINGS CONCERNING AERODYNAMIC EFFECTS IN SKI-JUMPING

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Engineering mathematics - Reflections on the dialectics of in and for

Poster presented at the conference