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

Channel optical waveguide directional couplers

We report the first demonstration of channel optical waveguide directional couplers. The closely spaced channel waveguides were fabricated in GaAs by proton implantation. Optical coupling was observed at 1.15 µ with complete light transfer out of the initial channel into adjacent channels in lengths of typically 2 mm

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

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

Community and company capacity: the challenge of resource-led development in Zambia's 'New Copperbelt'

Relationships between the extractive industries, society and development are often symbolized by unfulfilled expectations and even conflict. The poor, rural, politically marginalized and indigenous communities often face the greatest impacts by the extraction of energy and non-energy minerals. This paper explores the challenge of resource-led development in Zambia’s ‘New Copperbelt’, i.e. the Northwestern Province. It demonstrates how Kansanshi, a mid-tier mining company, has struggled with various community development aspects from resettlement and compensation, hiring and employment, as well as local government interactions, to formulating a coherent corporate social responsibility (CSR) and infrastructure project strategy. Findings suggest that community capacity to hold Kansanshi and local government to account is relatively weak. Recommendations include aligning CSR strategies with district, regional and national development objectives, as well as building linkages between local civil society organizations (CSOs) and national/international nongovernmental organizations (NGOs) to enable communities around the mine to share experiences, lessons learned, and effective company and local government engagement strategies

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

Anthropometric discriminators of type 2 diabetes among White and Black American adults

BACKGROUND: The aim of the present study was to determine the best anthropometric discriminators of type 2 diabetes mellitus (T2DM) among White and Black males and females in a large US sample. METHODS: We used Atherosclerosis Risk in Communities study baseline data (1987–89) from 15 242 participants (1827 with T2DM) aged 45–65 years. Anthropometric measures included a body shape index (ABSI), body adiposity index (BAI), body mass index, waist circumference (WC), waist:height ratio (WHtR), and waist:hip ratio (WHR). All anthropometric measures were standardized to Z-scores. Using logistic regression, odds ratios for T2DM were adjusted for age, physical activity, and family history of T2DM. The Akaike information criterion and receiver operating characteristic C-statistic were used to select the best-fit models. RESULTS: Body mass index, WC, WHtR, and WHR were comparable discriminators of T2DM among White and Black males, and were superior to ABSI and BAI in predicting T2DM (P < 0.0001). Waist circumference, WHtR, and WHR were the best discriminators among White females, whereas WHR was the best discriminator among Black females. The ABSI was the poorest discriminator of T2DM for all race–gender groups except Black females. Anthropometric values distinguishing T2DM cases from non-cases were lower for Black than White adults. CONCLUSIONS: Anthropometric measures that included WC, either alone or relative to height (WHtR) or hip circumference (WHR), were the strongest discriminators of T2DM across race–gender groups. Body mass index was a comparable discriminator to WC, WHtR, and WHR among males, but not females

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