6,870 research outputs found
Coded scanning of optical images
Coded mask for improved signal to noise ratio in scanning optical system
Studies on Emission Processes in Optically Pumped Mercury Vapor
Electron transitions in optically pumped mercury vapor emissio
Standardized Pearson type 3 density function area tables
Tables constituting extension of similar tables published in 1936 are presented in report form. Single and triple parameter gamma functions are discussed. Report tables should interest persons concerned with development and use of numerical analysis and evaluation methods
Optical Properties of Crystals with Spatial Dispersion: Josephson Plasma Resonance in Layered Superconductors
We derive the transmission coefficient, , for grazing incidence of
crystals with spatial dispersion accounting for the excitation of multiple
modes with different wave vectors for a given frequency . The
generalization of the Fresnel formulas contains the refraction indices of these
modes as determined by the dielectric function . Near
frequencies , where the group velocity vanishes, depends
also on an additional parameter determined by the crystal microstructure. The
transmission is significantly suppressed, if one of the excited modes is
decaying into the crystal. We derive these features microscopically for the
Josephson plasma resonance in layered superconductors.Comment: 4 pages, 2 figures, epl.cls style file, minor change
Coupling of intrinsic Josephson oscillations in layered superconductors by charge fluctuations
The coupling of Josephson oscillations in layered superconductors is studied
with help of a tunneling Hamiltonian formalism. The general form of the current
density across the barriers between the superconducting layers is derived. The
induced charge fluctuations on the superconducting layers lead to a coupling of
the Josephson oscillations in different junctions. A simplified set of
equations is then used to study the non-linear dynamics of the system. In
particular the influence of the coupling on the current-voltage characteristics
is investigated and upper limits for the coupling strength are estimated from a
comparison with experiments on cuprate superconductors.Comment: To be published in proceedings of SPIE conference San Diego 199
Use of accelerometry to investigate physical activity in dogs receiving chemotherapy
Objectives:
To perform a preliminary study to assess whether single-agent palliative or adjuvant chemotherapy has an impact on objectively measured physical activity in dogs.
Methods:
Fifteen dogs with neoplasia (treatment group) wore ActiGraphâ„¢ accelerometers for 5-day periods before, during and after receiving single-agent adjuvant or palliative chemotherapy. Mean 5-day total physical activity and time spent in three different intensities of activity (sedentary, light-moderate and vigorous) before, during and after receiving chemotherapy were compared to a group of 15 healthy dogs (control group). Results were also compared within the treatment group across time.
Results:
Prior to chemotherapy, treated dogs tended to be less active than control dogs. Treatment group dogs were slightly more active at restaging than they were prior to treatment but had similar activity levels to control dogs. Marked effects of chemotherapy on physical activity were not detected. Physical activity was slightly lower in treated dogs during chemotherapy when compared to control dogs but there was a slight increase in physical activity of treated dogs during chemotherapy when compared with pretreatment recordings. There was little change in the mean 5-day total physical activity between treated dogs during chemotherapy and at restaging but a mild decrease in time spent sedentary and increase in time spent in light-moderate activity at this comparison of time points.
Clinical Significance:
Single-agent adjuvant or palliative chemotherapy had minimal impact on physical activity levels in dogs with neoplasia
Satellite-Assisted Assessment Of The Effects Of Human Development On Coral Reefs, Roatan Honduras
Human intervention is degrading coastal marine environments on a global scale. Coral reefs are one of the most valuable ecosystems occupying coastal areas that provide a vast majority of consumable fish, recreational activities, and protection from extreme events, such as tropical cyclones. Unfortunately, as human development activities such as the construction of buildings, road infrastructure, and agriculture increase in coastal areas, so do the detrimental impacts on the health of coral reefs. Consequences of coastal development such as pollution, sedimentation, eutrophication, overfishing, and recreational activities have been linked to diminished coral health. A degraded coral ecosystem can often be identified by a reduction in coral cover and an increase in macroalgae. This change is associated with a phenomenon known as a phase shift that occurs in response to environmental stressors. This research investigates the relationships between increasing human development activities and coral and macroalgae extent on and surrounding the Caribbean island of Roatan, Honduras. The extent of land development and coral reefs are classified from a series of Landsat images from 1985 to 2015. Coral reef healthiness is evaluated based on coral and macroalgae covers and their temporal variations. A spatial gridding system is used to assess the relatedness between the development pressures and the health of coral reefs over the 30-year period. Out of the 36 sampled grids, seven showed a statistically significant relationship between urban area change and a change in either coral or macroalgae populations. This study demonstrates the capability of remote sensing to monitor coral reefs responding to land development of Roatan, Honduras
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