Coastal hazard mapping in the Cuddalore region, South India

It is estimated that nearly one-third of India’s population lives on the coast and is dependent on its resources. Shoreline erosion, storm surges and extreme events have resulted in severe loss of human life, damage to ecosystems and to property along the coast of India. Studies carried out in the Cuddalore region of South India reveal that this low-lying coastal zone, which suffered significant erosion during the last century, has been severely affected by the tsunami of 2004, storm floods and cyclones. In response to these impacts, a variety of coastal defense measures and adaptation strategies have been implemented in the region, although with only limited success. In order to inform future coastal planning in this region, the work reported here identifies a composite hazard line, seaward of which coastal flooding events will have a return interval of less than 1 in 100 years. The area landward of the coastal hazard line will be unaffected by 100 years of coastal erosion at present day rates. The study directly supports the Integrated Coastal Zone Management (ICZM) Plan of the Tamil Nadu State through the identification and assessment of coastal hazards and the overall vulnerability to coastal flooding and erosion. The key results from this pilot study will be used directly by the State of Tamil Nadu in the protection of the coastal livelihoods, better conservation measures and sustainable development along the coast. This study is a step toward mapping the hazard line for the entire coast of India that helps protect human lives and property.     

Magma mixing and the generation of isotopically juvenile silicic magma at Yellowstone caldera inferred from coupling 238U–230Th ages with trace elements and Hf and O isotopes in zircon and Pb isotopes in sanidine

The nature of compositional heterogeneity within large silicic magma bodies has important implications for how silicic reservoirs are assembled and evolve through time. We examine compositional heterogeneity in the youngest (~170 to 70 ka) post-caldera volcanism at Yellowstone caldera, the Central Plateau Member (CPM) rhyolites, as a case study. We compare ²³⁸U–²³⁰Th age, trace-element, and Hf isotopic data from zircons, and major-element, Ba, and Pb isotopic data from sanidines hosted in two CPM rhyolites (Hayden Valley and Solfatara Plateau flows) and one extracaldera rhyolite (Gibbon River flow), all of which erupted near the caldera margin ca. 100 ka. The Hayden Valley flow hosts two zircon populations and one sanidine population that are consistent with residence in the CPM reservoir. The Gibbon River flow hosts one zircon population that is compositionally distinct from Hayden Valley flow zircons. The Solfatara Plateau flow contains multiple sanidine populations and all three zircon populations found in the Hayden Valley and Gibbon River flows, demonstrating that the Solfatara Plateau flow formed by mixing extracaldera magma with the margin of the CPM reservoir. This process highlights the dynamic nature of magmatic interactions at the margins of large silicic reservoirs. More generally, Hf isotopic data from the CPM zircons provide the first direct evidence for isotopically juvenile magmas contributing mass to the youngest post-caldera magmatic system and demonstrate that the sources contributing magma to the CPM reservoir were heterogeneous in ¹⁷⁶Hf/¹⁷⁷Hf at ca. 100 ka. Thus, the limited compositional variability of CPM glasses reflects homogenization occurring within the CPM reservoir, not a homogeneous source.     

Walking as Method: Toward Methodological Forthrightness and Comparability in Urban Geographical Research

Qualitative urban geographical research should explicitly acknowledge insights gained from walking (the iterative exploration and observation of cities on foot), which enhances local literacy and enables researchers to compare methods more explicitly. Some urban geographers might use walking as a method, but it is rarely reported in published scholarship. This article argues for the explicit inclusion of walking in methodological reporting for urban research. We suggest that reporting the walking that researchers do adds rigor to research findings and should be distinguished from research where this practice is absent, we report on international experiences using walking in combination with other methods, and we conclude with a proposal for comparable urban geographic walking practices.     

The potential for the use of Open Source Software and Open Specifications in creating Web‐based cross‐border health spatial information systems

Globalization is contributing to the blurring of borders making irrelevant the distinctions between domestic and international health problems. Cross‐border and global health spatial information systems (CBHSIS) are required to address the new global health challenges. There is a need to build and document alternatives for addressing the technological, economic, and sociocultural–political challenges encountered in the creation and deployment of these systems. This paper documents the building of a prototype Web‐based multimedia GIS system for use in a public health context using Open Source Software and Open Specifications and its deployment across the US–Mexico border. These technologies offer advantages in addressing several of the challenges previously mentioned. We highlight the technological and sociocultural–political issues important in successful collaboration across borders and cultures and in the creation of interoperable CBHSIS.     

Transequatorial Filament Eruption and Its Link to a Coronal Mass Ejection

We revisit the Bastille Day flare/CME Event of 2000 July 14, and demonstrate that this flare/CME event is not related to only one single active region (AR). Activation and eruption of a huge transequatorial filament are seen to precede the simultaneous filament eruption and flare in the source active region, NOAA AR 9077, and the full halo-CME in the high corona. Evidence of reconfiguration of large-scale magnetic structures related to the event is illustrated by SOHO EIT and Yohkoh SXT observations, as well as, the reconstructed 3D magnetic lines of force based on the force-free assumption. We suggest that the AR filament in AR9077 was connected to the transequatorial filament. The large-scale magnetic composition related to the transequatorial filament and its sheared magnetic arcade appears to be an essential part of the CME parent magnetic structure. Estimations show that the filament-arcade system has enough magnetic helicity to account for the helicity carried by the related CMEs. In addition, rather global magnetic connectivity, covering almost all the visible range in longitude and a huge span in latitude on the Sun, is implied by the Nancay Radioheliograph (NRH) observations. The analysis of the Bastille Day event suggests that although the triggering of a global CME might take place in an AR, a much larger scale magnetic composition seems to be the source of the ejected magnetic flux, helicity and plasma. The Bastille Day event is the first described example in the literature, in which a transequatorial filament activity appears to play a key role in a global CME. Many tens of halo-CME are found to be associated with transequatorial filaments and their magnetic environment.     

Amplifier arrays for CMB polarization

Cryogenic low noise amplifier technology has been successfully used in the study of the cosmic microwave background (CMB). Monolithic millimeter wave integrated circuit (MMIC) technology makes the mass production of coherent detection receivers feasible. We have produced large numbers of MMIC amplifiers for CMB measurements. We have also demonstrated the viability of multi-function multi-chip modules as sensitive receiver front-ends. MMIC integration makes it possible to realize massive arrays of receivers suitable for measurements of the polarization of the CMB. We describe the development of the unit cell of such an array and the development plans for implementation.     

The effect of reionization on the COBE normalization

We point out that the effect of reionization on the microwave anisotropy power spectrum is not necessarily negligible on the scales probed by COBE . It can lead to an upward shift of the COBE normalization by more than the 1 σ error quoted, ignoring reionization. We provide a fitting function to incorporate reionization into the normalization of the matter power spectrum.