Evaluation of the Structural Integrity of Granular Composites by Ultrasonic Techniques

The development of the mechanical strength of composite materials which are consolidated by cementaceous bonds has been monitored by observation of the ultrasonic properties over the evolution of bond growth. The granular nature and weak bonding of these materials produce high attenuation of the ultrasonic signal and observation is difficult, particularly in larger structures. In order to obtain ultrasonic parameters with high resolution and to overcome the effects of grain scattering, a system based on a minicomputer and array processor has been implemented which provides time and frequency-domain processing and aperture synthesis. This ultrasonic data provides a reliable measure of the structural integrity of these materials

Intolerance of Uncertainty as a Contributor to Fear and Avoidance Symptoms of Panic Attacks

Panic disorder symptoms are persistent for 50–80% of cases even after treatment, resulting in experiences of disability and dissatisfaction in life. Previous research has focused on anxiety sensitivity (AS) and its dimensions as contributing to symptoms of panic disorder; however, recent research has suggested that intolerance of uncertainty (IU)—the tendency for a person to consider the possibility of a negative event occurring as threatening, irrespective of the actual probability of its occurrence—may also play a critical role. The current study was designed to assess the specific relationships between dimensions of IU (i.e. prospective IU and inhibitory IU) and the fear and avoidance symptoms associated with panic disorder. Participants included 122 community members (81% women) with a history of at least one panic attack who participated in a larger study on fear. Participants completed measures of AS, IU, and panic disorder symptoms. Correlation and regression analyses supported a significant and substantial relationship between AS, inhibitory IU, and panic disorder symptoms. Inhibitory IU accounted for relatively more variance in avoidance symptoms related to panic disorder than did the fears of physical sensations dimension of AS. As such, further investigation of the role of IU in panic disorder symptoms appears warranted. Comprehensive results, implications, and directions for future research are discussed

Does the Locally-Adaptive Model of Archaeological Potential (LAMAP) work for hunter-gatherer sites? A test using data from the Tanana Valley, Alaska

We report an assessment of the ability of the Locally-Adaptive Model of Archaeological Potential (LAMAP) to estimate archaeological potential in relation to hunter-gatherer sites. The sample comprised 182 known sites in the Tanana Valley, Alaska, which was occupied solely by hunter-gatherers for about 14,500 years. To estimate archaeological potential, we employed physiographic variables such as elevation and slope, rather than variables that are known to vary on short time scales, like vegetation cover. Two tests of LAMAP were carried out. In the first, we used the location of a random selection of 90 sites from all time periods to create a LAMAP model. We then evaluated the model with the remaining 92 sites. In the second test, we built a LAMAP model from 12 sites that pre-date 10,000 cal BP. This model was then tested with sites that post-date 10,000 cal BP. In both analyses, areas predicted to have higher archaeological potential contained higher frequencies of validation sites. The performance of LAMAP in the two tests was comparable to its performance in previous tests using archaeological sites occupied by agricultural societies. Thus, the study extends the use of LAMAP to the task of estimating archaeological potential of landscapes in relation to hunter-gatherer sites

Spatial Resolution of a Micromegas-TPC Using the Charge Dispersion Signal

The Time Projection Chamber (TPC) for the International Linear Collider will need to measure about 200 track points with a resolution close to 100 $\mu$m. A Micro Pattern Gas Detector (MPGD) readout TPC could achieve the desired resolution with existing techniques using sub-millimeter width pads at the expense of a large increase in the detector cost and complexity. We have recently applied a new MPGD readout concept of charge dispersion to a prototype GEM-TPC and demonstrated the feasibility of achieving good resolution with pads similar in width to the ones used for the proportional wire TPC. The charge dispersion studies were repeated with a Micromegas TPC amplification stage. We present here our first results on the Micromegas-TPC resolution with charge dispersion. The TPC resolution with the Micromegas readout is compared to our earlier GEM results and to the resolution expected from electron statistics and transverse diffusion in a gaseous TPC.Comment: 5 pages, 8 figures, to appar in the Proceedings of the 2005 International Linear Collider Workshop (LCWS05), Stanford, 18-22 March 200

Exploring Item Order in Anxiety-Related Constructs: Practical Impacts of Serial Position

The present study was designed to test for item order effects by measuring four distinct constructs that contribute substantively to anxiety-related psychopathology (i.e., anxiety sensitivity, fear of negative evaluation, injury/illness sensitivity, and intolerance of uncertainty). Participants (n = 999; 71% women) were randomly assigned to complete measures for each construct presented in one of two modalities: (a) items presented cohesively as measures or (b) items presented randomly interspersed with one another. The results suggested that item order had a relatively small impact on item endorsement, response patterns, and reliabilities. The small impact was such that item order appears unlikely to influence clinical decisions related to these measures. These findings not only have implications for these and other similar measures, but further inform a long-standing debate about whether item grouping is a substantial concern in measurement. Accessed 6,950 times on https://pareonline.net from April 21, 2012 to December 31, 2019. For downloads from January 1, 2020 forward, please click on the PlumX Metrics link to the right

Infrared Imaging of Capella with the IOTA Closure Phase Interferometer

We present infrared aperture synthesis maps produced with the upgraded IOTA interferometer. Michelson interferograms on the close binary system Capella (Alpha Aur) were obtained in the H-band between 2002 November 12 and 16 using the IONIC3 beam combiner. With baselines of 15m < B < 38m, we were able to determine the relative position of the binary components with milliarcsecond (mas) precision and to track their movement along the approx. 14 degree arc covered by our observation run. We briefly describe the algorithms used for visibility and closure phase estimation. Three different Hybrid Mapping and Bispectrum Fitting techniques were implemented within one software framework and used to reconstruct the source brightness distribution. By dividing our data into subsets, the system could be mapped at three epochs, revealing the motion of the stars. The precise position of the binary components was also determined with model fits, which in addition revealed I_Aa/I_Ab=1.49 +/- 0.10 and apparent stellar uniform-disk (UD) diameters of Theta_Aa=8.9 +/- 0.6 mas and Theta_Ab=5.8 +/- 0.8 mas. To improve the u, v-plane coverage, we compensated this orbital motion by applying a rotation-compensating coordinate transformation. The resulting model-independent map with a beam size of 5.4 x 2.6 mas allows the resolution of the stellar surfaces of the Capella giants themselves.Comment: Accepted by the Astronomical Journal (2005-03-21

An examination of the precipitation delivery mechanisms for Dolleman Island, eastern Antarctic Peninsula

Copyright @ 2004 Wiley-BlackwellThe variability of size and source of significant precipitation events were studied at an Antarctic ice core drilling site: Dolleman Island (DI), located on the eastern coast of the Antarctic Peninsula. Significant precipitation events that occur at DI were temporally located in the European Centre for Medium-Range Weather Forecasting (ECMWF) reanalysis data set, ERA-40. The annual and summer precipitation totals from ERA-40 at DI both show significant increases over the reanalysis period. Three-dimensional backwards air parcel trajectories were then run for 5 d using the ECMWF ERA-15 wind fields. Cluster analyses were performed on two sets of these backwards trajectories: all days in the range 1979–1992 (the climatological time-scale) and a subset of days when a significant precipitation event occurred. The principal air mass sources and delivery mechanisms were found to be the Weddell Sea via lee cyclogenesis, the South Atlantic when there was a weak circumpolar trough (CPT) and the South Pacific when the CPT was deep. The occurrence of precipitation bearing air masses arriving via a strong CPT was found to have a significant correlation with the southern annular mode (SAM); however, the arrival of air masses from the same region over the climatological time-scale showed no such correlation. Despite the dominance in both groups of back trajectories of the westerly circulation around Antarctica, some other key patterns were identified. Most notably there was a higher frequency of lee cyclogenesis events in the significant precipitation trajectories compared to the climatological time-scale. There was also a tendency for precipitation trajectories to come from more northerly latitudes, mostly from 50–70°S. The El Niño Southern Oscillation (ENSO) was found to have a strong influence on the mechanism by which the precipitation was delivered; the frequency of occurrence of precipitation from the east (west) of DI increased during El Niño (La Niña) events

Vascular endothelial growth factor in premenopausal women--indicator of the best time for breast cancer surgery?

Timing of surgery in premenopausal patients with breast cancer remains controversial. Angiogenesis is essential for tumour growth and vascular endothelial growth factor (VEGF) is one of the most potent angiogenic cytokines. We aimed to determine whether the study of VEGF in relation to the menstrual cycle could help further the understanding of this issue of surgical intervention. Fourteen premenopausal women were recruited, along with three post-menopausal women, a woman on an oral contraceptive pill and a single male subject. Between eight and 11 samples were taken per person, over one menstrual cycle (over 1 month in the five controls) and analysed for sex hormones and VEGF165. Serum VEGF was significantly lower in the luteal phase and showed a significant negative correlation with progesterone in all 14 premenopausal women. No inter-sample variations of VEGF were noted in the controls. Serum from both phases of the cycle from one subject was added to MCF-7 breast cancer cells; VEGF expression in the supernatant was lower in the cells to which the luteal phase serum was added. The lowering of a potent angiogenic cytokine in the luteal phase suggests a possible decreased potential for micrometastasis establishment in that phase. This fall in VEGF may be an effect of progesterone and should be the focus of future studies