Error characterization of spectral products using a factorial designed experiment

The main objective of any imaging system is to collect information. Information is conveyed in remotely sensed imagery by the spatial and spectral distribution of the energy reflected/emitted from the earth. This energy is subsequently captured by an overhead imaging system. Post-processing algorithms, which rely on this spectral and spatial energy distribution, allow us to extract useful information from the collected data. Typically, spectral processing algorithms include such procedures as target detection, thematic mapping and spectral pixel unmixing. The final spectral products from these algorithms include detection maps, classification maps and endmember fraction maps. The spatial resolution, spectral sampling and signal-to-noise characteristics of a spectral imaging system share a strong relationship with one another based on the law of conservation of energy. If any one of these initial image collection parameters were changed then we would expect the accuracy of the information derived from the spectral processing algorithms to also change. The goal of this thesis study was to investigate the accuracy and effectiveness of spectral processing algorithms under different image levels of spectral resolution, spatial resolution and noise. In order to fulfill this goal a tool was developed that degrades hyperspectral images spatially, spectrally and by adding spectrally correlated noise. These degraded images were then subjected to several spectral processing algorithms. The information utility and error characterization of these degraded spectral products is assessed using algorithm-specific metrics. By adopting a factorial designed experimental approach, the joint effects of spatial resolution, spectral sampling and signal-to-noise with respect to algorithm performance was also studied. Finally, a quantitative performance comparison of the tested spectral processing algorithms was made

Balance assessment in Multiple Sclerosis and cerebellar ataxia: rationale, protocol and demographic data

A core set of standardized balance measures are required for use in rehabilitation among people with multiple sclerosis (MS) and cerebellar ataxia. An earlier systematic review and Delphi survey identified the Berg Balance Scale (BBS), the Timed Up and Go test (TUG), Posture and Gait sub-component of the International Co-operative Ataxia Rating Scale (PG of ICARS) and the gait, sitting and stance sub-components of the Scale for the Assessment and Rating of Ataxia (SARA Bal) as suitable balance measures. This study aims to estimate the reliability, validity and interpretability of these measures. This study will recruit 60 participants with multiple sclerosis with secondary cerebellar involvement across four centres in New Zealand and the United States of America. Participants will be assessed and videotaped performing the BBS, TUG, SARA Bal and PG of ICARS by trained physiotherapists. Barthel Index, Expanded Disability Status Scale (EDSS), Disease duration, ICARS and SARA will also be assessed to determine validity. A second assessment to determine reliability will be conducted by assessors watching the video-recording. Data collection is in progress, 44 samples have been collected and the demographic data are presented. The findings of this study will recommend a core set of reliable, valid and interpretable measures that are suitable for clinical practice and research for the assessment of balance among adults with MS and cerebellar ataxia. Minimal Clinically Important Difference (MCID) and cut-off scores to predict the use of assistive walking device will be established

Looking bad: inferring criminality after 100 milliseconds

Research finds we make spontaneous trait inferences from facial appearance, even after brief exposures to a face (i.e., less than or equal to 100 ms). We examined spontaneous impressions of criminality from facial appearance, testing whether these impressions persist after repeated presentation (i.e., one to three exposures) and increased exposure duration (100, 500, or 1,000 ms) to the face. Judgement confidence and response times were recorded. Other participants viewed the faces for an unlimited period of time, rating trustworthiness, dominance and criminal appearance. We found evidence that participants spontaneously make criminal appearance attributions. These inferences persisted with repeated presentation and increased exposure duration, were related to trustworthiness and dominance ratings, and were made with high confidence. Implications are discussed

In silico approaches to study mass and energy flows in microbial consortia: a syntrophic case study

<p>Abstract</p> <p>Background</p> <p>Three methods were developed for the application of stoichiometry-based network analysis approaches including elementary mode analysis to the study of mass and energy flows in microbial communities. Each has distinct advantages and disadvantages suitable for analyzing systems with different degrees of complexity and <it>a priori </it>knowledge. These approaches were tested and compared using data from the thermophilic, phototrophic mat communities from Octopus and Mushroom Springs in Yellowstone National Park (USA). The models were based on three distinct microbial guilds: oxygenic phototrophs, filamentous anoxygenic phototrophs, and sulfate-reducing bacteria. Two phases, day and night, were modeled to account for differences in the sources of mass and energy and the routes available for their exchange.</p> <p>Results</p> <p>The <it>in silico </it>models were used to explore fundamental questions in ecology including the prediction of and explanation for measured relative abundances of primary producers in the mat, theoretical tradeoffs between overall productivity and the generation of toxic by-products, and the relative robustness of various guild interactions.</p> <p>Conclusion</p> <p>The three modeling approaches represent a flexible toolbox for creating cellular metabolic networks to study microbial communities on scales ranging from cells to ecosystems. A comparison of the three methods highlights considerations for selecting the one most appropriate for a given microbial system. For instance, communities represented only by metagenomic data can be modeled using the pooled method which analyzes a community's total metabolic potential without attempting to partition enzymes to different organisms. Systems with extensive <it>a priori </it>information on microbial guilds can be represented using the compartmentalized technique, employing distinct control volumes to separate guild-appropriate enzymes and metabolites. If the complexity of a compartmentalized network creates an unacceptable computational burden, the nested analysis approach permits greater scalability at the cost of more user intervention through multiple rounds of pathway analysis.</p

The transcription factor BATF operates as an essential differentiation checkpoint in early effector CD8+ T cells

The transcription factor BATF is required for interleukin 17 (IL-17)-producing helper T cell (TH17) and follicular helper T cell (TFH) differentiation. Here, we show that BATF also has a fundamental role in regulating effector CD8+ T cell differentiation. BATF-deficient CD8+ T cells show profound defects in effector expansion and undergo proliferative and metabolic catastrophe early after antigen encounter. BATF, together with IRF4 and Jun proteins, binds to and promotes early expression of genes encoding lineage-specific transcription-factors (T-bet and Blimp-1) and cytokine receptors, while paradoxically repressing genes encoding effector molecules (IFN-γ and granzyme B). Thus, BATF amplifies TCR-dependent transcription factor expression and augments inflammatory signal propagation but restrains effector gene expression. This checkpoint prevents irreversible commitment to an effector fate until a critical threshold of downstream transcriptional activity has been achieved

Surgery for pituitary tumor apoplexy is associated with rapid headache and cranial nerve improvement

Pituitary tumor apoplexy (PTA) classically comprises sudden-onset headache, loss of vision, ophthalmoparesis, and decreased consciousness. It typically results from hemorrhage and/or infarction within a pituitary adenoma. Presentation is heterologous, and optimal management is debated. The time course of recovery of cranial nerve deficits (CNDs) and headaches is not well established. In this study, a retrospective series of consecutive patients with PTA managed at a single academic institution over a 22-year period is presented. Headaches at the time of surgery were more severe in the early and subacute surgical cohort and improved significantly within 72 h postoperatively