Church-based social capital, networks and geographical scale: Katrina evacuation, relocation, and recovery in a New Orleans Vietnamese American community

This research examines the role of social capital and networks to explain the evacuation, relocation, and recovery experiences of a Vietnamese American community in New Orleans, Louisiana in the aftermath of Hurricane Katrina. As the single largest community institution, the parish church’s complex bonding and bridging social capital and networks proved particularly critical in part because of its historically based ontological security. The process of evacuation, but especially relocation and recovery, was dependent on deploying co-ethnic social capital and networks at a variety of geographical scales. Beyond the local or community scale, extra-local, regional, and national scales of social capital and networks reproduced a spatially redefined Vietnamese American community. Part of the recovery process included constructing discursive place-based collective-action frames to successfully contest a nearby landfill that in turn engendered social capital and networks crossing ethnic boundaries to include the extra-local African American community. Engaging social capital and networks beyond the local geographical scale cultivated a Vietnamese American community with an emergent post-Katrina cultural and political identity.     

The Effects of Tidal Export from Salt Marsh Ditches on Estuarine Water Quality and Plankton Communities

Salt marshes are an important transition zone between terrestrial and marine ecosystems, and in their natural state, they often function to cycle or trap terrestrially derived nutrients and organic matter. Many US salt marshes were ditched during the twentieth century, potentially altering their functionality. The goal of this 4-year study was to assess the impact of water from ditches within seven salt marshes on estuarine water quality and plankton communities within four estuaries on Long Island, NY, USA. We found that concentrations of inorganic nutrients (ammonium, phosphate), dissolved and particulate organic nitrogen and carbon (POC, PON, DOC, DON), and total coliform bacteria were significantly enriched in salt marsh ditches compared to the estuaries they discharged into. In addition, concentrations of ammonium and DON became more enriched in ditches as tidal levels decreased, suggesting these constituents were generated in situ. Quantification of nitrogen sources in Flanders Bay, NY, suggested salt marsh ditches could represent a substantial source of N to this estuary during summer months. Experimental incubations demonstrated that water from salt marsh ditches was capable of significantly enhancing the growth of multiple classes of phytoplankton, with large diatoms and dinoflagellates displaying the most dramatic increases in growth. Experiments further demonstrated that salt marsh ditchwater was capable of significantly enhancing pelagic respiration rates, suggesting discharge from ditches could influence estuarine oxygen consumption. In summary, this study demonstrates that tidal draining of salt marsh ditches is capable of degrading multiple aspects of estuarine water quality.     

Palynological evidence for Pennsylvanian (Late Carboniferous) vegetation change in the Sydney Coalfield,eastern Canada

The palynology of clastic samples from seven stratigraphical levels in the late Moscovian Sydney Mines Formation, exposed along the shore at Bras d'Or, Nova Scotia, has been investigated. Most of the samples were from roof shales of major coals; the one sample that was not yielded a much higher proportion of pollen derived from extra‐basinal vegetation. The four stratigraphically lower roof shale samples yielded essentially similar palynological spectra, with 39 ± 4% lycophytes, 9 ± 4% sphenophylls, 23 ± 4% tree‐ferns, 12 ± 4% other ferns and 5 ± 3% cordaites. The palynology of the upper part of the investigated succession suggests a shift in vegetation towards one favouring more marattialean tree‐ferns, cordaites and conifers, and fewer lycophytes. This correlates with changes in drainage patterns as the alluvial plain migrated seawards and thus changed water tables. No evidence was found to suggest significant climate change at this time. Copyright © 2009 John Wiley & Sons, Ltd.     

Titanite dates crystallization: Slow Pb diffusion during super‐solidus re‐equilibration

Titanite can be found in rocks of wide compositional range, is reactive, growing or regrowing during metamorphic and hydrothermal events, and is generally amenable to U–Pb geochronology. Experimental evidence suggest that titanite has a closure temperature for Pb ranging from 550 to 650°C, and thus titanite dates are commonly interpreted as cooling ages. However, this view has been challenged in recent years by evidence from natural titanite which suggests the closure temperature may be significantly higher (up to 800°C). Here, we investigate titanite in an enclave of migmatitic gneiss included within a granite intrusion. The titanite crystals exhibit textural features characteristic of fluid‐mediated mass transfer processes on length scales of <100 µm. These textural features are associated with variation in both Pb concentrations and distinct U–Pb isotopic compositions. Zr‐in‐titanite thermometry indicates that modification of the titanite occurred at temperatures in excess of 840°C, in the presence of a high‐T silicate melt. The Pb concentration gradients preserved in these titanite crystals are used to determine the diffusivity of Pb in titanite under high‐T conditions. We estimate diffusivities ranging from 2 × 10^?22 to 5 × 10^?25 m²/s. These results are significantly lower than experimental data predict yet are consistent with other empirical data on natural titanites, suggesting that Pb diffusivity is similar to that of Sr. Thus our data challenge the wide‐held assumption that U–Pb titanite dates only reflect cooling ages.     

Surface complexation modeling of Cu(II) adsorption on mixtures of hydrous ferric oxide and kaolinite

Background  

The application of surface complexation models (SCMs) to natural sediments and soils is hindered by a lack of consistent models and data for large suites of metals and minerals of interest. Furthermore, the surface complexation approach has mostly been developed and tested for single solid systems. Few studies have extended the SCM approach to systems containing multiple solids.     

The conventions of agri-environmental practice in New Zealand: farmers, retail driven audit schemes and a new spirit of farming

Audit schemes dictating the parameters of environmentally and socially acceptable management practice have emerged as a pervasive feature of global agri-food production. While the impacts of such schemes on the global movement of food and fibre and the evolving terrains of power in agri-food relations are well documented, the associated reconstruction of farming identities in the localities where audits are implemented has received less attention. The emerging responses to audit schemes in the New Zealand kiwifruit and dairy sectors are key examples of the contentious nature through which auditing is incorporated within farming practice. Analysis of these responses reveals the potential for audits to alter the spirit of farming in New Zealand, initiating new conventions of interaction between producers and industries. Within a convention theory framework, the incorporation of auditing within standard management practice involves a negotiated process in which the farmers employ strategic justifications of their capability (and value) relative to the quality designations established by the audit. Rather than evaluate the relative merits of a farm, its product and its owner through the craft and skill of the independent land manager, successful farming is increasingly associated with the individual’s ability to conform to an audit’s structures. The global trend toward audit schemes suggests that similar challenges to the spirit of farming may be replicated in other contexts.     

Hypoxic events in Narragansett Bay, Rhode Island, during the summer of 2001

Bottom water hypoxic events were observed in Narragansett Bay, Rhode Island during the summer of 2001 using a towed sensor, vertical casts at fixed stations, and continuous monitoring buoys. This combination of approaches allowed for both extensive spatial and temporal sampling. Oxygen concentrations below the U.S. Environmental Protection Agency (EPA) acute hypoxia criterion of 2.3 mg l^?1 were observed in the northern parts of Narragansett Bay, including the Providence River. We estimate 39% of the area of the Providence River was affected by acute hypoxia between July and September 2001. All other regions experienced only small areas of acute hypoxia (<5%), and no acute hypoxia was observed from Quonset Point south. The area encompassing oxygen concentrations below the EPA chronic hypoxia criterion of 4.8 mg l^?1 was much more extensive in the upper half of Narragansett Bay, sometimes covering the majority of the region, though it is unclear whether exposure to concentrations below this criterion persisted long enough to significantly affect marine species in these areas. Vertical profiles of dissolved oxygen typically exhibited a mid water oxygen minimum near the pycnocline, followed by a slight increase in oxygen with depth. The surface waters above the pycnocline were typically supersaturated with oxygen. The northern portions of the Bay where the most extensive hypoxia was observed corresponded to the regions with both the greatest thermohaline stratification, the highest nutrient inputs, and the highest primary productivity.     

A novel approach to leveraging social media for rapid flood mapping: a case study of the 2015 South Carolina floods

Rapid flood mapping is critical for local authorities and emergency responders to identify areas in need of immediate attention. However, traditional data collection practices such as remote sensing and field surveying often fail to offer timely information during or right after a flooding event. Social media such as Twitter have emerged as a new data source for disaster management and flood mapping. Using the 2015 South Carolina floods as the study case, this paper introduces a novel approach to mapping the flood in near real time by leveraging Twitter data in geospatial processes. Specifically, in this study, we first analyzed the spatiotemporal patterns of flood-related tweets using quantitative methods to better understand how Twitter activity is related to flood phenomena. Then, a kernel-based flood mapping model was developed to map the flooding possibility for the study area based on the water height points derived from tweets and stream gauges. The identified patterns of Twitter activity were used to assign the weights of flood model parameters. The feasibility and accuracy of the model was evaluated by comparing the model output with official inundation maps. Results show that the proposed approach could provide a consistent and comparable estimation of the flood situation in near real time, which is essential for improving the situational awareness during a flooding event to support decision-making.     

Comparison of undulation difference accuracies using gravity anomalies and gravity disturbances

Errors are considered in the outer zone contribution to oceanic undulation differences as obtained from a set of potential coefficients complete to degree 180. It is assumed that the gravity data of the inner zone (a spherical cap), consisting of either gravity anomalies or gravity disturbances, has negligible error. This implies that error estimates of the total undulation difference are analyzed. If the potential coefficients are derived from a global field of 1°×1° mean anomalies accurate to ε_Δg=10 mgal, then for a cap radius of 10°, the undulation difference error (for separations between 100 km and 2000 km) ranges from 13 cm to 55 cm in the gravity anomaly case and from 6 cm to 36 cm in the gravity disturbance case. If ε_Δg is reduced to 1 mgal, these errors in both cases are less than 10 cm. In the absence of a spherical cap, both cases yield identical error estimates: about 68 cm if ε_Δg=1 mgal (for most separations) and ranging from 93 cm to 160 cm if ε_Δg=10 mgal. Introducing a perfect 30-degree reference field, the latter errors are reduced to about 110 cm for most separations.     

The downward continuation of aerial gravimetric data without density hypothesis

Techniques for downward continuing gravity field data from aircraft altitude are well established if the earth's surface is either approximated by a plane or sphere, or is replaced by one of these surfaces using terrain corrections based on a density model. An alternative procedure is presented here where the continuation is analytical to a nontrivial surface, such as the actual topographic surface. Terrain elevations must be given, but density information is specifically not used.