Available fragile site identification software packages (FSM and FSM3) assume that all chromosomal breaks occur independently. However, under a Mendelian model of inheritance, homozygosity at fragile loci implies pairwise correlation between homologous sites. We construct correlation models for chromosomal breakage data in situations where either partitioned break count totals (per-site single-break and doublebreak totals) are known or only overall break count totals are known. We derive a likelihood ratio test and Neyman’s C( α) test for correlation between homologs when partitioned break count totals are known and outline a likelihood ratio test for correlation using only break count totals. Our simulation studies indicate that the C( α) test using partitioned break count totals outperforms the other two tests for correlation in terms of both power and level. These studies further suggest that the power for detecting correlation is low when only break count totals are reported. Results of the C( α) test for correlation applied to chromosomal breakage data from 14 human subjects indicate that detection of correlation between homologous fragile sites is problematic due to sparseness of breakage data. Simulation studies of the FSM and FSM3 algorithms using parameter values typical for fragile site data demonstrate that neither algorithm is significantly affected by fragile site correlation. Comparison of simulated fragile site misclassification rates in the presence of zero-breakage data supports previous studies (Olmsted 1999) that suggested FSM has lower false-negative rates and FSM3 has lower false-positive rates.

<p>Binary recompilation and translation play an important role in computer systems today. It is used by systems such as Java and .NET, and system emulators like VMWare and VirtualPC. A dynamic binary translator have several things in common with a regular compiler but as they usually have to translate code in real-time several constraints have to be made, especially when it comes to making code optimisations.</p><p>Designing a dynamic recompiler is a complex process that involves repetitive tasks. Translation tables have to be constructed for the source architecture which contains the data necessary to translate each instruction into binary code that can be executed on the target architecture. This report presents a method that allows a developer to specify how the source and target architectures work using a set of scripting languages. The purpose of these languages is to relocate the repetitive tasks to computer software, so that they do not have to be performed manually by programmers. At the end of the report a simple benchmark is used to evaluate the performance of a basic IA32 emulator running on a PowerPC target that have been implemented using the system described here. The results of the benchmark is compared to the results of running the same benchmark on other, existing, emulators in order to show that the system presented here can compete with the existing methods used today.</p><p>Several ongoing research projects are looking into ways of designing binary translators. Most of these projects focus on ways of optimising code in real-time and how to solve the problems related to binary translation, such as handling self-modifying code.</p>

Detection of the emission from the secondary component in a binary system can be extremely challenging, but equally rewarding. In the case of intermediate to high-mass binaries, detection of close companions can inform formation theories. In the extreme low mass-ratio case, where the secondary component is in fact a planet, detection of the emission in high resolution spectroscopy can be used to determine the true planet mass. In this thesis, we describe a technique to detect the thermal emission from the secondary component of a low mass-ratio binary system. We apply this technique to archived observations of early B-type stars using VLT/CRIRES, and simulate future observations of planetary systems with IGRINS, a near-infrared spectrograph being built now. / text

This dissertation is an observational exploration of the exciting physics that can be enabled by high-speed photometric monitoring of extremely low-mass (< 0.25 M[subscript sun symbol]) white dwarf stars, which are found in some of the most compact binaries known. It includes the cleanest indirect detection of gravitational waves at visible wavelengths, the discovery of pulsations in He-core WDs, the strongest evidence for excited p-mode pulsations in a WD, the discovery of the first tidally distorted WDs and their use to constrain the low-end of the WD mass-radius relationship, and the strongest cases of Doppler beaming observed in a binary system. It is the result of the more than 220 nights spent at McDonald Observatory doing high-speed photometry with the Argos instrument on the 2.1 m Otto Struve telescope, which has led to a number of additional exciting results, including the discovery of an intermediate timescale in the evolution of cooling DA WDs and the discovery of the most massive pulsating WD, which should have an ONe-core and should be highly crystallized. / text

No description available.

Globular clusters are extreme stellar populations. They have the highest stellar density, and host both the oldest and most metal-poor stellar populations in the Galaxy. Their densities make them excellent testbeds for stellar dynamics, while the properties of their stars allows us to test our understanding of old and metal-poor stellar evolution. This thesis is comprised of three projects studying the two nearest globular clusters, NGC 6397 and Messier 4. By examining high-quality HST photometry of NGC 6397, we have constrained the binary fraction in both the central regions, and beyond the half-light radius. We find a binary fraction of ~0.05 in the core and ~0.015 in the outskirts. In the context of recent N-body simulations by Hurley et al., we interpret the observed binary fraction in the outer field as the primordial binary fraction. This value is lower than typically assumed, and has implications for cluster dynamics and N-body modeling. We report the discovery that young white dwarfs are dynamically hotter than their progenitors. Using the same photometry as mentioned above, and archival HST photometry of Messier 4, we have found that young white dwarfs have an extended radial distribution, and therefore a higher velocity dispersion, compared with older white dwarfs and their progenitors. This implies the existence of a ``natal kick''. Implications for cluster dynamics and stellar evolution are discussed. Finally, we present the spectra of 23 white dwarfs in Messier 4 obtained with the Keck/LRIS and Gemini/GMOS spectrographs. We find that all white dwarfs are of type DA. Assuming the same DA/DB ratio as is observed in the field, the chance of finding no DBs in our sample due to statistical fluctuations is 0.006. This suggests DB formation is suppressed in the cluster environment. Furthermore, we constrain the mass of these white dwarfs by fitting models to the spectral lines. Our best estimate of the masses of the white dwarfs currently forming in Messier 4 is 0.51+/-0.02 M_sun.This extends the empirical constraint on the initial-final mass relation over the entire range of initial masses that could have formed white dwarfs in a Hubble time.

We present a mixture of latent trait models with common slope parameters (MCLT) for high dimensional binary data, a data type for which few established methods exist. Recent work on clustering of binary data, based on a d-dimensional Gaussian latent variable, is extended by implementing common factor analyzers. We extend the model further by the incorporation of random block effects. The dependencies in each block are taken into account through block-specific parameters that are considered to be random variables. A variational approximation to the likelihood is exploited to derive a fast algorithm for determining the model parameters. The Bayesian information criterion is used to select the number of components and the covariance structure as well as the dimensions of latent variables. Our approach is demonstrated on U.S. Congressional voting data and on a data set describing the sensory properties of orange juice. Our examples show that our model performs well even when the number of observations is not very large relative to the data dimensionality. In both cases, our approach yields intuitive clustering results. Additionally, our dimensionality-reduction method allows data to be displayed in low-dimensional plots. / Early Researcher Award from the Government of Ontario (McNicholas); NSERC Discovery Grants (Browne and McNicholas).

A binary clutter is cycling if its packing and covering linear program have integral optimal solutions for all Eulerian edge capacities. We prove that the clutter of odd st- walks of a signed graph is cycling if and only if it does not contain as a minor the clutter of odd circuits of K5 nor the clutter of lines of the Fano matroid. Corollaries of this result include, of many, the characterization for weakly bipartite signed graphs, packing two- commodity paths, packing T-joins with small |T|, a new result on covering odd circuits of a signed graph, as well as a new result on covering odd circuits and odd T-joins of a signed graft.

No description available.

An examination of 14 indexes for determining the number of clusters is conducted on artificial binary data sets being generated according to various design factors. To provide a variety of clustering solutions the data sets are analyzed by different non hierarchical clustering methods. The purpose of the paper is to present the performance and the ability of an index to detect the proper number of clusters in a binary data set under various conditions and different difficulty levels. (author's abstract) / Series: Working Papers SFB "Adaptive Information Systems and Modelling in Economics and Management Science"