The S2 Baseband Processing System for Phase-coherent Pulsar Observations

Hidden Markov models (HMM) have been proposed as a method of analysis for noisy single-molecule fluorescence resonance energy transfer (SM FRET) data. However, there are practical and fundamental limits in applying HMM to SM FRET data due to the short photobleaching lifetimes of fluorophores and the limited time resolution of detection devices. The fast photobleaching fluorophores yield short SM FRET time traces, and the limited detection time resolution generates abnormal FRET values, which result in systematic underestimation of kinetic rates. In this work, a HMM algorithm is implemented to optimize one set of HMM parameters with multiple short SM FRET traces. The FRET efficiency distribution function for the HMM optimization was modified to accommodate the abnormal FRET values resulting from limited detection time resolution. Computer simulations reveal that one set of HMM parameters is optimized successfully using multiple short SM FRET traces and that the degree of the kinetic rate underestimation is reduced by using the proposed modified FRET efficiency distribution. In conclusion, it is demonstrated that HMM can be used to reproducibly analyze short SM FRET time traces.

Po-topic III-05: Techniques for determining the blood input function in small animal pet imaging

The limits of time resolution are being reduced dramatically with the development of ever shorter laser pulses. In this communication I discuss the potential for approaching these limits by experiments in the frequency domain using electro-optic (E0) phase-sensitive detection. The method is used to separate Raman scattering (RS) from spontaneous emission and to measure the rate of fluorescence decay.

Fourier transform-infrared spectrometers have dominated the marketplace and the experimental literature of vibrational spectroscopy for almost three decades. These versatile instruments have been applied to a wide variety of measurements in both industrial and research settings. There has been, however, an ongoing need for enhanced time resolution. Limitations of time resolution in FT-IR measurements arise from the modulation frequencies intrinsic to the spectral multiplexing. Events which are slower than the minimum scan time, about 40 milliseconds at 4-cm−1 resolution, can be readily monitored with conventional instrumentation. For shorter transients, various step-scan, stroboscopic and asynchronous methods have been demonstrated to provide excellent time resolution, down to nanoseconds, but these approaches are limited to events which can be repeated many times with minimal variations. Some of these methods are also susceptible to low-frequency noise sources. The intrinsic scan time of conventional FT-IR spectrometers is limited by the force that can be applied to the moving mirror. In commercial systems the moving mirror is invariably driven by a voice coil linear motor. The maximum force that can be exerted by the voice coil is sharply limited to a few Newtons. It is desirable to decrease the scan time by a large factor, but the required force scales as the square of the scan rate, while the voltage applied to the coil must scale as the cube of the rate. A more suitable approach to very-rapid-scan FT-IR spectrometry may be the use of rotating optical components which do not have to turn around at the end of travel. There is, however, an apparent symmetry mismatch between rotating elements and the nominally planar wavefronts in a Michelson interferometer. In spite of the mismatch, numerous interferometer designs based on rotating elements have been proposed and demonstrated. Some of these designs are suitable for operation with scan times from tens of milliseconds to milliseconds, and perhaps faster, at 4-cm−1 resolution. A novel interferometer design utilizing a single-sided precessing disk mirror allows a complete interferogram to be measured in 1 millisecond or less. A prototype instrument of this design has been constructed and tested. One application reported here is the measurement of a transient combustion event. While combustion reactions can be conveniently repeated under some circumstances, such as with gas-phase reactants, the shot-to-shot variation is unacceptably large for step-scan measurements. Preliminary data, illustrating operation and performance of the system, are presented. It is thought that the high modulation frequencies have resulted in superior rejection of multiplicative noise.

Functional cardiac imaging with 3rd generation CT scanners is challenging, because the temporal resolution seems to be limited to approximately 2/3 of the rotation time of the gantry. We propose a new method for high temporal resolution volume heart imaging with multirow detectors based on a retrospective electrocardiogram-gated rebinning procedure. The limited time resolution is overcome using time consistent projection data retrieved from more than one cardiac cycle. In principle the method provides volume heart imaging with adjustable time resolution at arbitrary cardiac phases. It can be applied both for spiral and axial scan imaging. The presented study is based on computer simulations incorporating a model of the human heart taking into account anatomy, motion and heart rate variability. For multirow detectors we were able to show that good image quality can be obtained even during systole with temporal resolution which even exceeds that provided by an Electron Beam Scanner in standard mode of operation. Using an area detector with detector height > 3 cm (center of rotation) the total measurement time is within one breathhold for complete volume imaging of the heart. Furthermore, freezing motion of the coronary arteries during enddiastole allows high quality 3D display of coronary anatomy.

Repeated pulses of cyclic AMP, applied at intervals of 5 min, efficiently induced differentiation in cells of agip 53, a morphogenetic mutant of Dictyostelium discoideum, strain Ax-2. In contrast, pulses applied at intervals of 2 min did not induce cell differentiation. To analyze this phenomenon the hydrolysis of cyclic AMP between the pulses as well as the effect of the pulses on the intracellular concentrations of cyclic GMP were investigated. Experiments performed in the presence of added cyclic AMP was not the reason of the inefficiency of the pulses applied with a 2-min rhythm. Cyclic AMP pulses applied at intervals of 2 min induced discrete increases of the cyclic GMP concentration. Limited time resolution at the level of cyclic GMP cannot account for the inefficiency of the 2-min pulses.

Characterization of a Compton camera based on the TOFPET2 ASIC

We present the first study on the use of sound recordings to assess the activity of carrion flies as an alternative to labour intensive physical capture and identification with limited time resolution. Daily recordings were made of the fly activity on human cadavers in a simulated disaster scenario at the Australian Facility for Taphonomic Experimental Research (AFTER). The recordings were manually analysed for flight sounds and compared to the local environmental data. The results showed that the number of flight sounds was significantly affected by the temperature, daylight, and moderate to high rainfall but not by humidity. Reference recordings were also made of Blow flies (Diptera: Calliphoridae), Flesh flies (Diptera: Sarcophagidae), House flies (Diptera: Muscidae) and the Black Soldier flies (Stratiomyidae: Hermetia illucens) in a commercial fly farm and used to build a statistical classification model to test the feasibility of audio recognition for successional studies. Successional arrival and departure patterns were not observed for the recorded flies, although this could be the result of ineffective audio classification algorithm. Further in-depth studies are currently being done on different species and variations within the same species.

Imaging the interaction between the laser pulse and photoresist mixture on the ultrafast time scale can track the path of the light pulse and reveal the procedure of the microstructure machining. However, most existing imaging technologies suffer from problems such as requiring multiple repeated shots or a limited time resolution. To overcome these problems, we propose to capture the motion of laser pulses in a photoresist mixture by using compressed ultrafast photography (CUP). In this method, we can recover the motion process of non-repeatable events with a single shot at the time-resolution of about 1.54×1011 fps, where the depth of the imaging sequence reaches hundreds of frames. To verify the effectiveness of the proposed method, we estimate the speed of the laser pulse in a photoresist mixture and evaluate the similarity between the image captured by a streak camera and our reconstructed ultrafast sequence; the results validate the reliability of our proposed method.

The ultrafast detection of single photons is currently restricted by the limited time resolution (a few picoseconds) of the available single-photon detectors. Optical gates offer a faster time resolution, but so far they have been applied mostly to ensembles of emitters. Here, we demonstrate through a semi-analytical model that the ultrafast time-resolved detection of single quantum emitters can be possible using an optical Kerr shutter at gigahertz rates under focused illumination. This technique provides sub-picosecond time resolution, while keeping a gate efficiency at around 85%. These findings lay the ground for future experimental investigations on the ultrafast dynamics of single quantum emitters, with implications for quantum nanophotonics and molecular physics.

It has recently become evident that the functional connectome of the human brain is a dynamical entity whose time evolution carries important information underpinning physiological brain function as well as its disease-related aberrations. While simple sliding window approaches have had some success in estimating dynamical brain connectivity in a functional MRI (fMRI) context, these methods suffer from limitations related to the arbitrary choice of window length and limited time resolution. Recently, Generalized autoregressive conditional heteroscedastic (GARCH) models have been employed to generate dynamical covariance models which can be applied to fMRI. Here, we employ a GARCH-based method (dynamic conditional correlation - DCC) to estimate dynamical brain connectivity in the Human Connectome Project (HCP) dataset and study how the dynamic functional connectivity behaviors related to personality as described by the five-factor model. Openness, a trait related to curiosity and creativity, is the only trait associated with significant differences in the amount of time-variability (but not in absolute median connectivity) of several inter-network functional connections in the human brain. The DCC method offers a novel window to extract dynamical information which can aid in elucidating the neurophysiological underpinning of phenomena to which conventional static brain connectivity estimates are insensitive.

Time-resolved studies of quantum systems are the key to understanding quantum dynamics at its core. The real-time measurement of individual quantum numbers as they switch between certain discrete values, well known as a "random telegraph signal," is expected to yield maximal physical insight. However, the signal suffers from both systematic errors, such as a limited time resolution and noise from the measurement apparatus, as well as statistical errors due to a limited amount of data. Here we demonstrate that an evaluation scheme based on factorial cumulants can reduce the influence of such errors by orders of magnitude. The error resilience is supported by a general theory for the detection errors as well as experimental data of single-electron tunneling through a self-assembled quantum dot. Thus, factorial cumulants push the limits in the analysis of random telegraph data, which represent a wide class of experiments in physics, chemistry, engineering, and life sciences.

Purpose: To develop a method for modeling the dynamic relationship between patient surface motion and internal target motion using 4DCT data. Then, to verify its capability to interpolate internal target motion with real‐time patient surface motion information. Methods and Materials: At discrete phases of a respiration cycle, the coordinates of points in a grid with specific interval on patient surface and internal target were automatically extracted from 4DCT data, then used for the experiments. A radial basis function (RBF) based neural network was employed for modeling purpose. The model was examined by eight sets of data, which consists of the coordinates of points on a patient surface and a region of interest (ROI) on either the left lung or right lung. Results: With fine sampling (grid interval < 5 voxels) of the patient surface and internal target, less than 5% interpolation error was found in seven experiments. one patient (right side of left lung) with error more than 8% and unexpected displacement more than 10 mm in 4DCT was observed. Coarse sampling (grid interval >10 voxels) will result in a larger interpolation error. In seven successful cases, the interpolation errors less than 2mm. The only failed one had interpolation error of 4 mm. Conclusion: A dynamic model is established for correlating patient surface motion with internal target motion based on 4DCT data. An acceptable interpolation accuracy is achieved for 7 of 8 cases examined in this study. The only failed one implied that for target motion with larger displacement and higher frequency, the model based on 4DCT data might be not sufficient because of its limited time resolution in acquiring those information in a respiration cycle.

The Kansas District of the Water Resources Division, U.S. Geological Survey, in cooperation with the State Geological Survey of Kansas, has been establishing a data-processing system for the storage and retrieval of hydrologic data since 1963. The data bank developed contains thousands of well-inventory, water-quality, water-level and lithologic-log records. Accuracy of data in the bank is assured through a system that begins with coding forms, includes computer programs that check for logic errors, and ends with manual proofing of computer output. Numerous computer programs that manipulate and analyze data from the bank have been written and these programs have enhanced the interpretive capability of a hydrologist. Methods of examining data that were not practicable before the advent of the computer are now feasible. Computer usage has encouraged development of new analytical techniques and the adaptation of methods from other scientific fields for hydrologic data interpretation. Utilizing a high-speed digital computer, the Kansas District can do specific tasks, achieving higher interpretive quality in less time and at lover cost. Introduction The Kansas District of the Water Resources Division, USGS, in cooperation with the Geological Survey of Kansas, has been developing techniques for handling hydrologic data with high-speed digital computers since 1963, in accord with guidelines established by the Water Resources Div., Washington, D. C. The techniques of coding, storing, retrieving and analyzing data are designed to facilitate the manipulation and synthesis of large quantities of basic data from a data bank. These data consist of tens of thousands of data sets [Table 11; a set being, for example, one chemical water analysis or one well-inventory record. Many programs may been written for use with these data; some programs were developed on the IBM 7040 and GE 625 computers at the U. of Kansas Computation Center, and are available for use on the USGS's IBM 360-65 Computer in Washington, D. C. COMPUTER ADVANTAGES Handling water data manually is a time consuming, impractical job when large-scale problems are considered, and large-scale problems are considered, and large-scale problems are becoming more evident as population problems are becoming more evident as population and industry increase. Many data-handling procedures used in the past, both for reports procedures used in the past, both for reports and in answering requests for information, require a multitude of repetitious operations. The availability of the digital computer made the development of an automatic data processing system an obvious solution for increasing the efficiency of handling water data. Unlike a hydrologist, the computer consistently does monotonous tasks accurately without tiring. The computer can do the repetitive work efficiently, allowing a hydrologist to pursue solutions to problems for which time formerly was not available. The development of a successful automatic data processing system may be considered as having two major facets: [1] a method must be perfected to enter the basic records into a perfected to enter the basic records into a computer data bank, and [21 programs must be developed to instruct the computer to select specified data from the bank and rearrange or manipulate the data to obtain the desired printout. printout. The use of a computer allows the hydrologist to examine all available data, thereby reducing costs since chances for error are reduced to a minimum. The actual cost of a normal project may not be reduced, but the data are examined more thoroughly in the same length of time.

An overview of translational, human oncogenomics, transcriptomics and cancer interactomic networks is presented together with basic concepts and potential, new applications to Oncology and Integrative Cancer Biology. Novel translational oncogenomics research is rapidly expanding through the application of advanced technology, research findings and computational tools/models to both pharmaceutical and clinical problems. A self-contained presentation is adopted that covers both fundamental concepts and the most recent biomedical, as well as clinical, applications. Sample analyses in recent clinical studies have shown that gene expression data can be employed to distinguish between tumor types as well as to predict outcomes. Potentially important applications of such results are individualized human cancer therapies or, in general, ‘personalized medicine’. Several cancer detection techniques are currently under development both in the direction of improved detection sensitivity and increased time resolution of cellular events, with the limits of single molecule detection and picosecond time resolution already reached. The urgency for the complete mapping of a human cancer interactome with the help of such novel, high-efficiency / low-cost and ultra-sensitive techniques is also pointed out.