Bucket-brigade device with improved charge transfer

The charge transfer of bucket-brigade devices can be considerably improved by the additional use of one transistor and one resistor per cell. The effect of this is demonstrated by a computer simulation.     

Investigation of polynya dynamics in the northern Bering Sea using greyscale morphology image-processing techniques

Arctic coastal polynyas, defined here as persistent openings in the winter sea ice pack, are significant areas for ocean–atmosphere heat exchange, high winter sea ice production with resulting brine rejection and the dependence of local ecosystems. It is therefore critical to accurately quantify polynya dynamics to understand their spatial and temporal variability, particularly in the context of recent dramatic Arctic sea ice declines. In this study, the so-called erosion algorithm (a greyscale morphology image-processing technique) is applied to satellite-derived sea ice concentrations in the northern Bering Sea to investigate polynya dynamics throughout this region. Greyscale morphology allows for the estimation of sea ice extent with a defined error tolerance through the removal of regions with low sea ice concentrations in the marginal ice zone. Furthermore, since polynyas are the primary source of water within the sea ice pack, the presence of water here can therefore be utilized to define the areal extent of polynyas. We utilized AMSR-E (Advanced Microwave Scanning Radiometer-EOS) sea ice concentrations during January–April from 2003 to 2008 in the northern Bering Sea to extract daily time series of water area within polynyas by a water integration method after data are preprocessed using greyscale morphology techniques. These results compare well with those calculated by more traditional methods utilizing sea ice concentration thresholds and show the great utility of greyscale morphology techniques as a preprocessing method (which eliminates artificial determination of polynya areal extents and enables automation of the overall image-processing routine). In addition, based on the results of our algorithms we investigated the potential driving forces (e.g. offshore wind velocity) of polynya development in the northern Bering Sea as well as calculate the spatial and interannual variability of heat fluxes across these water surfaces owing to polynya formation.     

The CTFA Evaluation of Alternatives Program: an evaluation of in vitro alternatives to the Draize primary eye irritation test. (Phase III) surfactant-based formulations

The CTFA Evaluation of Alternatives Program is an evaluation of the relationship between data from the Draize primary eye irritation test and comparable data from a selection of promising in vitro eye irritation tests. In Phase III, data from the Draize test and 41 in vitro endpoints on 25 representative surfactant-based personal care formulations were compared. As in Phase I and Phase II, regression modelling of the relationship between maximum average Draize score (MAS) and in vitro endpoint was the primary approach adopted for evaluating in vitro assay performance. The degree of confidence in prediction of MAS for a given in vitro endpoint is quantified in terms of the relative widths of prediction intervals constructed about the fitted regression curve. Prediction intervals reflect not only the error attributed to the model but also the material-specific components of variation in both the Draize and the in vitro assays. Among the in vitro assays selected for regression modeling in Phase III, the relationship between MAS and in vitro score was relatively well defined. The prediction bounds on MAS were most narrow for materials at the lower or upper end of the effective irritation range (MAS = 0-45), where variability in MAS was smallest. This, the confidence with which the MAS of surfactant-based formulations is predicted is greatest when MAS approaches zero or when MAS approaches 45 (no comment is made on prediction of MAS > 45 since extrapolation beyond the range of observed data is not possible). No single in vitro endpoint was found to exhibit relative superiority with regard to prediction of MAS. Variability associated with Draize test outcome (e.g. in MAS values) must be considered in any future comparisons of in vivo and in vitro test results if the purpose is to predict in vivo response using in vitro data.     

Spatio‐Temporal Contours from Deep Volume Raycasting

We visualize contours for spatio‐temporal processes to indicate where and when non‐continuous changes occur or spatial bounds are encountered. All time steps are comprised densely in one visualization, with contours allowing to efficiently analyze processes in the data even in case of spatial or temporal overlap. Contours are determined on the basis of deep raycasting that collects samples across time and depth along each ray. For each sample along a ray, its closest neighbors from adjacent rays are identified, considering time, depth, and value in the process. Large distances are represented as contours in image space, using color to indicate temporal occurrence. This contour representation can easily be combined with volume rendering‐based techniques, providing both full spatial detail for individual time steps and an outline of the whole time series in one view. Our view‐dependent technique supports efficient progressive computation, and requires no prior assumptions regarding the shape or nature of processes in the data. We discuss and demonstrate the performance and utility of our approach via a variety of data sets, comparison and combination with an alternative technique, and feedback by a domain scientist.     

Effect of irradiation on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) nanofiber conductivity

Conducting nanofibers of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)/polyvinyl alcohol (PEDOT:PSS/PVA) were fabricated at room temperature and via electrospinning with diameters ranging from 100 to 300 nm. The nanofibers were irradiated with Gamma and X-rays for varying lengths of time and the change in conductivity was evaluated. Raman and Electron Spin Resonance spectroscopy of X-ray irradiated nanofibers were obtained to determine the mechanism of conductivity degradation. A decrease in molecular ordering as well as chain scission via chain cross-linking and free radical formation are the two most likely mechanisms for change in conductivity. These nanofibers are promising candidates for use in highly sensitive, real-time electrically based sensor for radiation detection.