IJ Bias: The Contamination Theory

In the case of Apouviepseakoda v. Gonzales, the majority and the dissent of the Seventh Circuit heavily criticized the immigration judge’s behavior during the removal hearing. Yet, the majority seemed to go out of its way to affirm denial of asylum. The majority held that, although the IJ’s behavior during the asylum hearing was inappropriate, it did not amount to reversible error. The majority would reverse only if the IJ’s behavior were so inappropriate that it frazzled the asylum applicant or barred large portions of the applicant’s testimony. What this decision does not account for is the fact that the IJ, who was openly hostile towards the asylum applicant, was making a subjective finding regarding the asylum applicant’s truthfulness and believability. In such a situation, the Seventh Circuit’s rule requiring actual prejudice in addition to IJ bias will frequently result in the denial of otherwise valid asylum claims. Where the IJ exhibits bias against the asylum applicant, the ability of the IJ to serve as a fact-finder is compromised. When the basis for the denial of an asylum application is an adverse credibility determination, the threshold for a finding of reversible error should be much lower where the IJ exhibits bias against the asylum applicant

IJ Bias: The Contamination Theory

In the case of Apouviepseakoda v. Gonzales, the majority and the dissent of the Seventh Circuit heavily criticized the immigration judge’s behavior during the removal hearing. Yet, the majority seemed to go out of its way to affirm denial of asylum. The majority held that, although the IJ’s behavior during the asylum hearing was inappropriate, it did not amount to reversible error. The majority would reverse only if the IJ’s behavior were so inappropriate that it frazzled the asylum applicant or barred large portions of the applicant’s testimony. What this decision does not account for is the fact that the IJ, who was openly hostile towards the asylum applicant, was making a subjective finding regarding the asylum applicant’s truthfulness and believability. In such a situation, the Seventh Circuit’s rule requiring actual prejudice in addition to IJ bias will frequently result in the denial of otherwise valid asylum claims. Where the IJ exhibits bias against the asylum applicant, the ability of the IJ to serve as a fact-finder is compromised. When the basis for the denial of an asylum application is an adverse credibility determination, the threshold for a finding of reversible error should be much lower where the IJ exhibits bias against the asylum applicant

MRI On the Fly: Accelerating MRI Imaging Using LDA Classification with LDB Feature Extraction

To improve MRI acquisition time, we explored the uses of linear discriminant analysis (LDA), and local discriminant bases (LDB) for the task of classifying MRI images using a minimal set of signal acquisitions. Our algorithm has both off-line and on-line components. The off-line component uses the k-basis algorithm to partition a set of training images (all from a particular region of a patient) into classes. For each class, we find a basis by applying the best basis algorithm on the images in that class. We keep these bases to be used by the on-line process. We then apply LDB to the training set with the class assignments, determining the best discriminant basis for the set. We rank the basis coordinates according to discriminating power, and retain the top M coordinates for the on-line algorithm. We keep the top M coordinates, which index the basis functions with the most discriminating capability, for on-line purposes. Finally, we train LDA on these transformed coordinates, producing a classifier for the images. With the off-line requirements complete, we can take advantage of the simplicity and speed of the on-line mechanism to acquire an image in a similar region of the patient. We need acquire only the M important coordinates of the image in the discriminant basis to create a ``scout image.\u27\u27 This image, which can be acquired quickly since M is much much smaller than the number of measurements needed to fill in the values of the 256 by 256 pixels, is then sent through the map furnished by LDA which in turn assigns a class to the image. Returning to the list of bases that we kept from the k-bases algorithm, we find the optimal basis for the particular class at hand. We then acquire the image using that optimal basis, omitting the coefficients with the least truncation error. The complete image can then be quickly reconstructed using the inverse wavelet packet transform. The power of our algorithm is that the on-line task is fast and simple, while the computational complexity lies mostly in the off-line task that needs to be done only once for images in a certain region. In addition, our algorithm only makes use of the flexibility of MRI hardware, so no modifications in hardware design are needed

Metabolomic Profiling in Relation to New-Onset Atrial Fibrillation (from the Framingham Heart Study)

Previous studies have shown several metabolic biomarkers to be associated with prevalent and incident atrial fibrillation (AF), but the results have not been replicated. We investigated metabolite profiles of 2,458 European ancestry participants from the Framingham Heart Study without AF at the index examination and followed them for 10 years for new-onset AF. Amino acids, organic acids, lipids, and other plasma metabolites were profiled by liquid chromatography-tandem mass spectrometry using fasting plasma samples. We conducted Cox proportional hazard analyses for association between metabolites and new-onset AF. We performed hypothesis-generating analysis to identify novel metabolites and hypothesis-testing analysis to confirm the previously reported associations between metabolites and AF. Mean age was 55.1 +/- 9.9 years, and 53% were women. Incident AF developed in 156 participants (6.3%) in 10 years of follow-up. A total of 217 metabolites were examined, consisting of 54 positively charged metabolites, 59 negatively charged metabolites, and 104 lipids. None of the 217 metabolites met our a priori specified Bonferroni corrected level of significance in the multivariate analyses. We were unable to replicate previous results demonstrating associations between metabolites that we had measured and AF. In conclusion, in our metabolomics approach, none of the metabolites we tested were significantly associated with the risk of future AF

Microwave Ionization of an Atomic Electron Wave Packet

A short microwave pulse is used to ionize a lithium Rydberg wave packet launched from the core at a well-defined phase of the field. We observe a strong dependence on the relative phase between the motion of the wave packet and the oscillations of the field. This phase dependent ionization is also studied as a function of the relative frequency. Our experimental observations are in good qualitative agreement with a one-dimensional classical model of wave packet ionization

Simulating Active Layer Thaw in a Boreal Environment

A large part of the boreal zone of the western Canadian Arctic is underlain by ice-rich discontinuous permafrost which when thawed, can lead to settlement of the ground surface that has implications for the integrity of northern infrastructure, including oil and gas pipelines. A simple yet physically-based model is desired to simulate thawing of the active layer in different materials commonly found along the Mackenzie Valley pipeline corridor. Stefan’s algorithm determines the phase change of soil moisture using ground surface temperature as the upper boundary condition and conduction to transfer heat to the freeze-thaw front. It is tested on a permafrost site near Wrigley, Northwest Territories, where the computed thaw penetration compares satisfactorily with field data. To further explore the effects of climate and soil types on active layer depth, three representative sites in the Mackenzie valley where ground surface temperatures are available were selected for simulation of ground thaw, under two summer conditions. Results of the simulation demonstrate the sensitivity of active layer thaw to (1) soil materials due to differential thermal properties, (2) moisture content, which largely controls the latent heat requirement for phase change, and (3) inter-annual variations in ground surface temperature. Given the strong potential for environmental changes in the vast boreal region, the model allows the active layer thaw responses to be easily assessed.Simulation de la couche active de dégel d’un environnement boréal. Une vaste partie de la zone boréale de l’Arctique canadien occidental repose sur un pergélisol discontinu riche en glace qui, en dégelant, peut causer des problèmes de surface du sol pouvant compromettre l’intégrité des structures nordiques, dont les pipelines de pétrole et de gaz. Un modèle physique simple est nécessaire pour la simulation du dégel de la couche active des divers dépôts meubles trouvés le long du corridor du pipeline de la vallée du Mackenzie. L’algorithme de Stefan détermine la phase du changement d’humidité du sol en utilisant la température de surface comme la condition limite supérieure, et la conduction au transfert de la chaleur jusqu’au front de gel-dégel. Cet algorithme est appliqué à un site de pergélisol près de Wrigley, Territoires-du-Nord-Ouest, où la simulation de la profondeur de dégel se compare bien aux données de terrain. Afin d’explorer plus encore les effets du climat et du type de sol sur la profondeur de la couche active, trois sites représentatifs de la vallée du Mackenzie, où les températures de la surface du sol sont disponibles, ont été sélectionnés pour une simulation de dégel du sol, selon deux conditions estivales. Les résultats de la simulation montrent la sensibilité de la couche active de dégel (1) aux propriétés thermiques différentielles des matériaux du sol, (2) au contenu en humidité, qui contrôle la chaleur latente provoquant le changement de phase, et (3) aux variations interannuelles des températures de la surface du sol. En raison du fort potentiel de changements environnementaux dans la vaste région boréale, le modèle permet d’évaluer aisément le dégel de la couche active qui en constitue une réaction

Microwave Ionization of an Atomic Electron Wave Packet

A short microwave pulse is used to ionize a lithium Rydberg wave packet launched from the core at a well-defined phase of the field. We observe a strong dependence on the relative phase between the motion of the wave packet and the oscillations of the field. This phase dependent ionization is also studied as a function of the relative frequency. Our experimental observations are in good qualitative agreement with a one-dimensional classical model of wave packet ionization

Robust Analysis of Metabolic Pathways

Flux Balance Analysis (FBA) is a widely used computational model for studying the metabolic pathways of cells and the role individual metabolites and reactions play in maintaining cell function. However, the successes of FBA have been limited by faulty biological assumptions and computational imperfections. We introduce Robust Analysis of Metabolic Pathways (RAMP) to provide a more theoretically sound and computationally accurate model of cellular metabolism. RAMP overcomes the faulty assumptions of traditional FBA by allowing deviation from steady-state and accounting for variability across a cellular culture. Computationally, RAMP more successfully predicts the lethality of gene knockouts and reduces degeneracy in optimal ux values. Analytical results establish the stability of RAMP under perturbations in modeling parameters. The inclusion of new modeling parameters in RAMP opens the possibility of modeling different cellular cultures in a wider range of conditions, including non- optimized cultures. We conclude that RAMP is an improvement over traditional FBA and deserves further study