Analysis of radar images of the active volcanic zone at Krafla, Iceland: The effects of look azimuth biasing

The geomorphic expression of Mid-Ocean-Ridge (MOR) volcanism in a subaerial setting occurs uniquely on Earth in Iceland, and the most recent MOR eruptive activity has been concentrated in the Northeastern Volcanic Zone in an area known as Krafla. Within the Krafla region are many of the key morphologic elements of MOR-related basaltic volcanism, as well as volcanic explosion craters, subglacial lava shields, tectonic fissure swarms known as gjar, and basaltic-andesite flows with well developed ogives (pressure-ridges). The objective was to quantify the degree to which the basic volcanic and structural features can be mapped from directional SAR imagery as a function of the look azimuth. To accomplish this, the current expression of volcanic and tectonic constructs was independently mapped within the Krafla region on the E, W, and N-looking SAR images, as well as from SPOT Panchromatic imagery acquired in 1987. The initial observations of the E, W, and N images indicates that fresh a'a lava surfaces are extremely radar bright (rough at 3 cm to meter scales) independent of look direction; this suggests that these flows do not have strong flow direction related structures at meter and cm scales, which is consistent with typical Icelandic a'a lava surfaces in general. The basic impression from a preliminary analysis of the effects of look azimuth biasing on interpretation of the geology of an active MOR volcanic zone is that up to 30 percent of the diagnostic features can be missed at any given look direction, but that having two orthogonal look direction images is probably sufficient to prevent gross misinterpretation

K/T age for the popigai impact event

The multi-ringed POPIGAI structure, with an outer ring diameter of over 100 km, is the largest impact feature currently recognized on Earth with an Phanerozoic age. The target rocks in this relatively unglaciated region consist of upper Proterozoic through Mesozoic platform sediments and igneous rocks overlying Precambrian crystalline basement. The reported absolute age of the Popigai impact event ranges from 30.5 to 39 Ma. With the intent of refining this age estimate, a melt-breccia (suevite) sample from the inner regions of the Popigai structure was prepared for total fusion and step-wise heating Ar-40/Ar-39 analysis. Although the total fusion and step-heating experiments suggest some degree of age heterogeneity, the recurring theme is an age of around 64 to 66 Ma

A critical analysis of some distinctively religious resources utilized in pastoral care, with an experimental evaluation

https://place.asburyseminary.edu/ecommonsatsdissertations/2389/thumbnail.jp

Ion beam micromachining of integrated optics components

Thin film integrated optics components such as light guides, modulators, directional couplers, and polarizers demand high quality edge smoothness and high resolution pattern formation in dimensions down to submicrometer size. Fabrication techniques combining holographic and scanning electron beam lithography with ion beam micromachining have produced planar phase gratings with intervals as small as 2800 Å, guiding channel couplers in GaAs, and also wire- grid polarizers for 10.6-µm radiation

Mobilizing a CGIAR Agricultural Insurance Research Community

This report summarizes the proceedings of the workshop; “Mobilizing a CGIAR Agricultural Insurance Research Community,” held in Washington, D.C., January 20-22. 29 participants representing 14 CGIAR Centers (AfricaRice, CIAT, CIMMYT, ICARDA, ICRAF, IFPRI, ILRI, CCAFS, IWMI, IRRI) came together to participate in the workshop. The CCAFS Regional Programs of East and West Africa, and South and Southeast Asia were also represented. The workshop aimed to mobilize a community of practice on weather-related insurance for agricultural development and adaptation, take stock of relevant expertise and approaches across the CGIAR, and inform the development of funding proposals under CCAFS Flagship 2: Climate Information Services and Climate-Informed Safety Nets. Three opening keynote speakers provided background on index insurance and some of the successfully scaled projects, creating a context for the broader ideological discussions to follow. Some topics discussed included the use of index insurance as a development tool and as part of a greater risk management strategy; how agricultural research can engage the insurance industry; and index insurance data challenges. The second workshop day involved a mapping activity, to take stock of the activities of the CGIAR around the world in agricultural insurance as well as capture the methods, innovations, tools, and gaps and challenges of these projects. The third day supported workshop participants to explore synergies, and take advantage of writing a proposal for a funding opportunity through CCAFS. This workshop guided participants to share ideas, knowledge, approaches and resources, fostering a stronger community of practice across the CGIAR centers. Outputs from this workshop include a more populated community of practice website, several projects on index insurance approved for funding through CCAFS, and plans for a journal special issue

Channel Optical Waveguides and Directional Couplers in GaAs -- Imbedded and Ridged

Two-channel imbedded directional couplers were fabricated with proton implantation, yielding complete light transfer in 2 mm. Ridged channel guides were fabricated by ion-micromachining epitaxial layers, and a method of directional coupling was demonstrated

Optically pumped GaAs surface laser with corrugation feedback

A GaAs distributed-feedback laser was fabricated and pumped optically. A narrow stimulated spectrum was obtained around 0.83 µ with threshold pumping power of ~2 × 10^5 W/cm^2

Oxidized basalts on the surface of Venus: Compositional implications of measured spectral properties

Venera Lander reflectance data are compared with high temperature spectra of the same basaltic materials. The dark, flat unoxidized basalts are still inconsistent with the Venera data in the near-infrared. Basaltic material with a ferric component, however, would satisfy both the increase in reflectance beyond 0.7 microns as well as the dark, relatively colorless character in the visible. Therefore, it is concluded that besaltic surfaces of Venus represented by these measurements either contain minerals with uncommon characteristics, or, more likely, are relatively oxidized