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The application of moisture to the ear is anecdotally claimed to relieve the pain from otic barotrauma that can arise during aircraft descent. This claim was tested in a randomised double-blind study on an aircraft with eight participants heavily predisposed to barotrauma.
On the outward flight, half the participants wore ‘active’ devices that applied moisture to the external ear; the remainder wore placebo devices that contained no moisture, but were otherwise identical. On the return flight, the groups were reversed. Participants wore the devices from just before descent until landing, unless they experienced symptoms of barotrauma, in which case they switched to what they knew was an active device.
There were no significant differences between conditions regarding the appearance of the tympanic membrane on landing or the discomfort levels immediately before and after any switch.
Applying moisture is ineffective for passengers heavily predisposed to otic barotrauma.
A network of relatively fast-flowing tributaries in the catchment basins of the West Antarctic ice streams transport ice from the inland reservoir to the heads of the ice streams. Branches of the network follow valleys in basal topography but not all valleys contain tributaries. We investigate the circumstances favoring tributary flow upstream of Ice Streams D and E, using a combination of observation and numerical modelling. No consistent pattern emerges. The transition from tributary to ice-stream flow occurs smoothly along the main tributary feeding into the onset of Ice Stream D, with ice thickness being relatively more important upstream, and sliding being relatively more important downstream. Elsewhere, the downstream pattern of flow is more complicated, with local increases and decreases in the contribution of sliding to ice speed. Those changes may be due to variations in basal water storage, subglacial geologic properties or a combination of the two.
The spatial pattern of accumulation rate can be inferred from internal layers in glaciers and ice sheets. Non-dimensional analysis determines where finite strain can be neglected (‘shallow-layer approximation’) or approximated with a local one-dimensional flow model (‘local-layer approximation’), and where gradients in strain rate along particle paths must be included (‘deep layers’). We develop a general geophysical inverse procedure to infer the spatial pattern of accumulation rate along a steady-state flowband, using measured topography of the ice-sheet surface, bed and a ‘deep layer’. A variety of thermomechanical ice-flow models can be used in the forward problem to calculate surface topography and ice velocity, which are used to calculate particle paths and internal-layer shapes. An objective tolerance criterion prevents over-fitting the data. After making site-specific simplifications in the thermomechanical flow algorithm, we find the accumulation rate along a flowband through Taylor Mouth, a flank site on Taylor Dome, Antarctica, using a layer at approximately 100 m depth, or 20% of the ice thickness. Accumulation rate correlates with ice-surface curvature. At this site, gradients along flow paths critically impact inference of both the accumulation pattern, and the depth-age relation in a 100 m core.
This paper briefly describes the principle of operation and science goals of the AMANDA high energy neutrino telescope located at the South Pole, Antarctica. Results from an earlier phase of the telescope, called AMANDA-BIO, demonstrate both reliable operation and the broad astrophysical reach of this device, which includes searches for a variety of sources of ultrahigh energy neutrinos: generic point sources, Gamma-Ray Bursts and diffuse sources. The predicted sensitivity and angular resolution of the telescope were confirmed by studies of atmospheric muon and neutrino backgrounds. We also report on the status of the analysis from AMANDA-II, a larger version with far greater capabilities. At this stage of analysis, details of the ice properties and other systematic uncertainties of the AMANDA-II telescope are under study, but we have made progress toward critical science objectives. In particular, we present the first preliminary flux limits from AMANDA-II on the search for continuous emission from astrophysical point sources, and report on the search for correlated neutrino emission from Gamma Ray Bursts detected by BATSE before decommissioning in May 2000. During the next two years, we expect to exploit the full potential of AMANDA-II with the installation of a new data acquisition system that records full waveforms from the in-ice optical sensors.
Our knowledge about the impact of coping behavior styles in people exposed to stressful disaster events is limited. Effective coping behavior has been shown to be a psychosocial stress modifier in both occupational and nonoccupational settings.
Data were collected by using a web-based survey that administered the Post-Traumatic Stress Disorder (PTSD) Checklist–Civilian, General Coping Questionnaire-30, and a supplementary questionnaire assessing various risk factors. Logistic regression models were used to test for the association of the 3 coping styles with probable PTSD following disaster exposure among federal disaster responders.
In this sample of 549 study subjects, avoidant coping behavior was most associated with probable PTSD. In tested regression models, the odds ratios ranged from 1.19 to 1.26 and 95% confidence intervals ranged from 1.08 to 1.35. With control for various predictors, emotion-based coping behavior was also found to be associated with probable PTSD (odds ratio=1.11; 95% confidence interval: 1.01-1.22).
This study found that in disaster responders exposed to traumatic disaster events, the likelihood of probable PTSD can be influenced by individual coping behavior style and other covariates. The continued probability of disasters underscores the critical importance of these findings both in terms of guiding mental health practitioners in treating exposed disaster responders and in stimulating future research. (Disaster Med Public Health Preparedness. 2016;10:108–117)
In nature, biomolecules guide the formation of hierarchically-ordered, lightweight, inorganic-organic composites such as corals, shells, teeth and bones. M13 bacteriophage has been used to mimic bio-inspired material development due to its rigid, nanoscale rod-like morphology. Liquid-crystalline monolayers of genetically engineered phage have been used to template crystallization of thin layers of inorganic and metallic materials. We have created thin films composed of engineered M13 phage capable of binding inorganic components. We employed both a dip-cast and a drop-cast film fabrication method on both smooth and rough gold, silica and glass casting surfaces to create thin films and 3D structures of various degrees of hierarchical order. We have found the engineered M13 phage and the inorganic mineral significantly affected both film morphology and the mechanical properties of the film. Similarly, film fabrication parameters such as solution chemistry, temperature, and pulling speed affected film properties. Using a calcium phosphate biomineralized 4E phage, film thickness increased linearly with the number of layers/dips in the phage solution. The stiffness of these composites (Young's modulus) were >80 GPa for mineralized, multilayer films. These materials are an order of magnitude stiffer than the biological equivalent collagen. Stiffness, however, does not appear to increase in a multilayer film beyond a saturation point. Ultimately, we have developed a platform for phage-based bio-composites for developing high performance materials.
We have used MBE to grow graded InxGa1−xAs/GaAs superlattices on GaAs substrates as buffers for larger period, constant composition InxGa1−xAs/GaAs superlattices. TEM analysis shows that there are numerous crystal defects associated with the presence of strained layers, but, in many cases, the buffer layers confine these defects to areas outside of the strained-layer superlattices. PIN detectors fabricated from these structures show external quantum efficiencies up to 2.7 %.
In this paper we report a new approach to the problem of high rate formation of nanophase powders. In our experiments we were able to make aluminum oxide particles in the size range from 5 to 140 nm (peaking sharply at 35 nm) at a rate of 3 g/min. The starting material was a mixture of aluminum-tri-sec-butoxide and sec-butanol. An aerosol was made from this solution and subsequently burned in a special torch, described below. The resulting particles were spherical and no necked regions were observable between them. In a practical application, our technique allows a large production rate while still approaching the ideal of nano-scale monodispersed particles. The work was extended to the formation of zirconium oxide particles with quite similar results in the size distribution.
Two NDT techniques were used to characterize low-density, microcellular, carbon foams fabricated from a salt replica process. The two techniques are x-ray computed tomography (CT) and ion microtomography (IMT); data are presented on carbon foams that contain high-density regions. The data show that densities which differ by <10% are easily observable for these low density (<100 mg/cm3) materials. The data reveal that the carbon foams produced by this replica process have small density variations; the density being ∼30% greater at the outer edges than when compared to the interior of the foam. In addition, the density gradient is found to be rather sharp, that is the density drops-off rapidly from the outer edges to a uniform one in the interior of the foam. This edge build-up in carbon density was explained in terms of polymer concentrating on the foam exterior during drying which immediately followed a polymer infusion processing step. Supporting analytical data from other techniques show the foam material to be >99.9 % carbon
After describing some recent developments in atomic force microscopy (AFM), a specific application to the study of shell ultrastructure is examined in detail. By embedding bleached nacreous tablets in epoxy and imaging them with the atomic force microscope (AFM) during in situ dissolution, it was possible to visualize the topography of both the top faces of the tablets and the impressions in epoxy made by the bottom faces of the tablets. This epoxy imprint reproduced tablet features down to the 10 nm scale. Using this technique it should be possible to measure correspondence between topographic features on the proximal and distal faces of tablets, which is necessary to form a three-dimensional picture of the nacreous region. In addition to these dissolution experiments, growth experiments (in modified sea water) on bleached, embedded tablets indicated that aragonite grows on a tablet as asperities oriented along the c axis, normal to the tablet surface. No change was seen on the surface of the epoxy, which confirmed that the crystals were growing on the tablet surface, not spontaneously nucleating out of solution.
The Ion Micro-Analysis Group (IMAG) in Livermore conducts quantitative trace elemental analysis with PIXE and depth profiling with IBS using an MeV ion microbeam. The system has the capability to produce two-dimensional trace element and IBS images. PIXE analyses have been conducted on HgI2 and PbI2 crystals and detector materials in order to identify and quantify near surface trace contaminants. IBS measurements have been conducted to investigate elemental depth distributions in various materials. The results of measurements on several different samples are reported and a discussion of factors affecting quantitative in vacuo microanalysis of these materials is presented.
Significant developments have occurred in the technology of room-temperature PbI2 nuclear sensors which lead to some improvements in the detection of high energy gamma-rays. Discussion of crystal growth, purification, monitoring purification, and detector processing are reviewed as they relate to device performance.
Metal-Semiconductor-Metal (MSM) photodiodes fabricated from low temperature (LT) grown GaAs by molecular beam epitaxy have been characterized for wavelengths extending out to 1.5μm. External quantum efficiencies on the order of 0.5 % have been measured for subbandgap wavelengths, which translates to internal quantum efficiencies of 2–4 % for the interdigitated electrode structure with lμm finger spacing and width. Although the effective lifetime of the LT-GaAs has been determined to be <1ps, an MSM photodiode response of ∼10ps full width at half maximum was measured by correlation techniques at 820 nm wavelength, and a system limited response of 3GHz was measured at 1.3 μm wavelength. These experimental results will be described in detail.
In this study we report on the results of the investigation of lead iodide material properties. The effectiveness of a zone refining purification method on the material purity is determined by ICP-MS and ICP-OES and correlated to the electrical and physical material properties. We show that this zone refining method is very efficient in removing impurities from lead iodide, and we also determine the segregation coefficient for some of these impurities. Triple axis x-ray diffraction (TAD) analysis has been used to determine the crystalline perfection of the lead iodide after applying various cutting, etching and fabrication methods. The soft lead iodide crystal was found to be damaged when cleaved by a razor blade, but by using a diamond wheel saw, followed by etching, the crystallinity of the material was much improved, as observed by TAD. Low temperature photoluminescence also indicates an improvement in the material properties of the purified lead iodide. Electrical properties of lead iodide such as carrier mobility, were calculated based on carrier - phonon scattering. The results for the electrical properties were in good agreement with the experimental data.