Data-driven efficient score tests for deconvolution problems

We consider testing statistical hypotheses about densities of signals in deconvolution models. A new approach to this problem is proposed. We constructed score tests for the deconvolution with the known noise density and efficient score tests for the case of unknown density. The tests are incorporated with model selection rules to choose reasonable model dimensions automatically by the data. Consistency of the tests is proved

Numerical Comparison of Cusum and Shiryaev-Roberts Procedures for Detecting Changes in Distributions

The CUSUM procedure is known to be optimal for detecting a change in distribution under a minimax scenario, whereas the Shiryaev-Roberts procedure is optimal for detecting a change that occurs at a distant time horizon. As a simpler alternative to the conventional Monte Carlo approach, we propose a numerical method for the systematic comparison of the two detection schemes in both settings, i.e., minimax and for detecting changes that occur in the distant future. Our goal is accomplished by deriving a set of exact integral equations for the performance metrics, which are then solved numerically. We present detailed numerical results for the problem of detecting a change in the mean of a Gaussian sequence, which show that the difference between the two procedures is significant only when detecting small changes.Comment: 21 pages, 8 figures, to appear in Communications in Statistics - Theory and Method

Short-Term Exercise Training Does Not Stimulate Skeletal Muscle ATP Synthesis in Relatives of Humans With Type 2 Diabetes

OBJECTIVE-We tested the hypothesis that short-term exercise training improves hereditary insulin resistance by stimulating ATP synthesis and investigated associations With gene polymorphisms. RESEARCH DESIGN AND METHODS-We studied 24 nono-bese first-degree relatives of type 2 diabetic patients and 12 control subjects at rest, and 48 h after three bouts of exercise. In addition to measurements of oxygen uptake and insulin sensitivity (oral glucose tolerance test), ectopic lipids and mitochondrial ATP synthesis were assessed using H-1 and P-31 magnetic resonance spectroscopy, respectively. They were genotyped for polymorphisms in genes regulating mitochondrial function, PPARGC1A (rs8192678) and NDUFB6 (rs540467). RESULTS-Relatives had slightly lower (P = 0.012) insulin sensitivity than control subjects. In control subjects, ATP synthase flux rose by 18% (P = 0.0001), being 23% higher (P = 0.002) than that in relatives after exercise training. Relatives responding to exercise training with increased ATP synthesis (+19%, P = 0.009) showed improved insulin sensitivity (P = 0.009) compared with those whose insulin sensitivity did not improve. A polymorphism in the NDUFB6 gene from respiratory chain complex I related to ATP synthesis (P = 0.02) and insulin Sensitivity response to exercise training (P = 0.05). ATP synthase flux correlated with O-2 uptake and insulin sensitivity. CONCLUSIONS-The ability of short-term exercise to stimulate ATP production distinguished individuals with improved insulin sensitivity from those whose insulin sensitivity did not improve. lit addition, the NDUFB6 gene polymorphism appeared to modulate this adaptation. This finding suggests that genes involved in mitochondrial function contribute to the response of ATP synthesis to exercise training. Diabetes 58:1333-1341, 200

Classical signal model reproducing quantum probabilities for single and coincidence detections

We present a simple classical (random) signal model reproducing Born's rule. The crucial point of our approach is that the presence of detector's threshold and calibration procedure have to be treated not as simply experimental technicalities, but as the basic counterparts of the theoretical model. We call this approach threshold signal detection model (TSD). The experiment on coincidence detection which was done by Grangier in 1986 \cite{Grangier} played a crucial role in rejection of (semi-)classical field models in favor of quantum mechanics (QM): impossibility to resolve the wave-particle duality in favor of a purely wave model. QM predicts that the relative probability of coincidence detection, the coefficient $g^{(2)}(0),$ is zero (for one photon states), but in (semi-)classical models $g^{(2)}(0)\geq 1.$ In TSD the coefficient $g^{(2)}(0)$ decreases as $1/{\cal E}_d^2,$ where ${\cal E}_d>0$ is the detection threshold. Hence, by increasing this threshold an experimenter can make the coefficient $g^{(2)}(0)$ essentially less than 1. The TSD-prediction can be tested experimentally in new Grangier type experiments presenting a detailed monitoring of dependence of the coefficient $g^{(2)}(0)$ on the detection threshold

Making sense of perceptions of risk of diseases and vaccinations: a qualitative study combining models of health beliefs, decision-making and risk perception

<p>Abstract</p> <p>Background</p> <p>Maintaining high levels of childhood vaccinations is important for public health. Success requires better understanding of parents' perceptions of diseases and consequent decisions about vaccinations, however few studies have considered this from the theoretical perspectives of risk perception and decision-making under uncertainty. The aim of this study was to examine the utility of subjective risk perception and decision-making theories to provide a better understanding of the differences between immunisers' and non-immunisers' health beliefs and behaviours.</p> <p>Methods</p> <p>In a qualitative study we conducted semi-structured in-depth interviews with 45 Australian parents exploring their experiences and perceptions of disease severity and susceptibility. Using scenarios about 'a new strain of flu' we explored how risk information was interpreted.</p> <p>Results</p> <p>We found that concepts of dread, unfamiliarity, and uncontrollability from the subjective perception of risk and ambiguity, optimistic control and omission bias from explanatory theories of decision-making under uncertainty were useful in understanding why immunisers, incomplete immunisers and non-immunisers interpreted severity and susceptibility to diseases and vaccine risk differently. Immunisers dreaded unfamiliar diseases whilst non-immunisers dreaded unknown, long term side effects of vaccines. Participants believed that the risks of diseases and complications from diseases are not equally spread throughout the community, therefore, when listening to reports of epidemics, it is not the number of people who are affected but the familiarity or unfamiliarity of the disease and the characteristics of those who have had the disease that prompts them to take preventive action. Almost all believed they themselves would not be at serious risk of the 'new strain of flu' but were less willing to take risks with their children's health.</p> <p>Conclusion</p> <p>This study has found that health messages about the risks of disease which are communicated as though there is equality of risk in the population may be unproductive as these messages are perceived as unbelievable or irrelevant. The findings from this study have implications beyond the issue of childhood vaccinations as we grapple with communicating risks of new epidemics, and indeed may usefully contribute to the current debate especially in the UK of how these theories of risk and decision-making can be used to 'nudge' other health behaviours.</p

The Transcriptional Response in Human Umbilical Vein Endothelial Cells Exposed to Insulin: A Dynamic Gene Expression Approach

BACKGROUND: In diabetes chronic hyperinsulinemia contributes to the instability of the atherosclerotic plaque and stimulates cellular proliferation through the activation of the MAP kinases, which in turn regulate cellular proliferation. However, it is not known whether insulin itself could increase the transcription of specific genes for cellular proliferation in the endothelium. Hence, the characterization of transcriptional modifications in endothelium is an important step for a better understanding of the mechanism of insulin action and the relationship between endothelial cell dysfunction and insulin resistance. METHODOLOGY AND PRINCIPAL FINDINGS: The transcriptional response of endothelial cells in the 440 minutes following insulin stimulation was monitored using microarrays and compared to a control condition. About 1700 genes were selected as differentially expressed based on their treated minus control profile, thus allowing the detection of even small but systematic changes in gene expression. Genes were clustered in 7 groups according to their time expression profile and classified into 15 functional categories that can support the biological effects of insulin, based on Gene Ontology enrichment analysis. In terms of endothelial function, the most prominent processes affected were NADH dehydrogenase activity, N-terminal myristoylation domain binding, nitric-oxide synthase regulator activity and growth factor binding. Pathway-based enrichment analysis revealed "Electron Transport Chain" significantly enriched. Results were validated on genes belonging to "Electron Transport Chain" pathway, using quantitative RT-PCR. CONCLUSIONS: As far as we know, this is the first systematic study in the literature monitoring transcriptional response to insulin in endothelial cells, in a time series microarray experiment. Since chronic hyperinsulinemia contributes to the instability of the atherosclerotic plaque and stimulates cellular proliferation, some of the genes identified in the present work are potential novel candidates in diabetes complications related to endothelial dysfunction

Pleasure in decision-making situations

BACKGROUND: This study explores the role of pleasure in decision making. RESULTS: In Experiment 1, 12 subjects were presented with a questionnaire containing 46 items taken from the literature. Twenty-three items described a situation where a decision should be made and ended with a suggested solution. The other items served as filler items. The subjects were requested not to make a decision but to rate the pleasure or displeasure they experienced when reading the situation described in the item. The subjects' ratings were then compared to the decisions on the same situations made by the other subjects of the studies published by other workers. The ratings of pleasure/displeasure given by our subjects correlated significantly with the choices published by other authors. This result satisfies a necessary condition for pleasure to be the key of the decision making process in theoretical situations. In Experiment 2, a new group of 12 subjects rated their experience of pleasure/displeasure when reading various versions of 50 situations taken from daily life where an ethical decision had to be made (Questionnaire I) including 200 items. This was followed by a multiple-choice test with the 50 situations (Questionnaire II) using the same 200 items and offering the various behaviors. Subjects tended to choose ethical and unethical responses corresponding to their highest pleasure rating within each problem. In all cases the subjects' behavior was higher than chance level, and thus, followed the trend to maximize pleasure. In Experiment 3, 12 subjects reading 50 mathematical short problems followed by correct and incorrect versions of the answer to the problem (Questionnaire III), including 200 items. This was followed by a multiple-choice mathematical test with the 50 problems (Questionnaire IV) using the same 200 items and offering the correct and incorrect answers. In questionnaire IV, subjects tended to choose correct as well as incorrect responses corresponding to their highest hedonic rating within each problem. In all cases the subjects' behavior was higher than chance level, and thus, followed the trend to maximize pleasure. CONCLUSIONS: The results of the three experiments support the hypothesis according to which decisions are made in the hedonic dimension of conscious experience