The human brain's ongoing activity is characterized by intrinsic networks of coherent fluctuations, measured for example with correlated functional magnetic resonance imaging signals. So far, however, the brain processes underlying this ongoing blood oxygenation level dependent (BOLD) signal orchestration and their direct relevance for human behavior are not sufficiently understood. In this stu...

PURPOSE Physiological fluctuations in biological tissues adversely affect MR images if present during signal acquisition. This problem is especially important for quantitative MRI. The goal of the studies reported in this study was to reduce the contributions of physiological fluctuations in quantitative MRI based on T2* tissue relaxation properties. Specifically, in this study we deal with GEP...

When considering human neuroimaging data, an appreciation of signal variability represents a fundamental innovation in the way we think about brain signal. Typically, researchers represent the brain's response as the mean across repeated experimental trials and disregard signal fluctuations over time as "noise". However, it is becoming clear that brain signal variability conveys meaningful func...

Cavity quantum electrodynamics describes the fundamental interactions between light and matter, and how they can be controlled by shaping the local environment. For example, optical microcavities allow high-efficiency detection and manipulation of single atoms. In this regime, fluctuations of atom number are on the order of the mean number, which can lead to signal fluctuations in excess of the...

This thesis has investigated objective measurements that relate to the perceived spatial attributes of reproduced sound. Research has been conducted into extant measurements that aim to quantify the perceived spatial attributes of concert hall acoustics, and those that are most likely to be successful for measuring the properties of reproduced sound have been identified. A relatively new measur...

Decoupling capacitors on packages and printed circuits boards are often essential to reduce voltage fluctuations and maintain power and signal integrity. This paper presents a measure for the evaluation of effectiveness of decoupling capacitors placed on package or board structures.

We investigated how moment-to-moment fluctuations in fMRI amplitude and interregional coupling are linked to behavioral performance during a stop signal task. To quantify the relationship between single-trial amplitude and behavior on a trial-by-trial basis, we modeled the probability of successful inhibition as a function of response amplitude via logistic regression analysis. At the group lev...

Signal transduction upon binding of a ligand to a membrane protein can occur not only via allosteric conformational changes but also through fluctuations. We report a numerical study on the influence of conformational fluctuations on the cooperativity of a binding reaction in a simple model of an integral membrane receptor consisting of transmembrane helices. We find that small fluctuations lat...

An MRI time course of 512 echo-planar images (EPI) in resting human brain obtained every 250 ms reveals fluctuations in signal intensity in each pixel that have a physiologic origin. Regions of the sensorimotor cortex that were activated secondary to hand movement were identified using functional MRI methodology (FMRI). Time courses of low frequency (< 0.1 Hz) fluctuations in resting brain were...

We introduce a new formalism to describe the polarization signal of galaxy clusters on the whole sky. We show that a sparsely sampled, half-sky map of the cluster polarization at z approximately 1 would allow us to better characterize the very large scale density fluctuations. While the horizon length is smaller in the past, two other competing effects significantly remove the contribution of t...