Life histories in cyberspace: life writing as a development tool for rural women

Increasingly, information and communication technology (ICT) is being used as a development tool. For example, a recent innovative experiment by the FIDAMERICA development cybernetwork (sponsored by IFAD, the International Fund for Agricultural Development) in Latin America used an electronic network to collect, post and discuss rural women's life histories, intending to support gender mainstreaming in IFAD projects. However, cybernetworking processes can also reflect contradictory agendas and power relations that ultimately make them a site of contestation. In the FIDAMERICA case, the authors did not participate in the electronic conference, nor were there any subsequent efforts to connect them or to develop this process further.In this paper, I argue that the analysis of increasingly complex cybernetworked development efforts must incorporate a correspondingly sophisticated technique that can uncover the nuanced relations of transnational cyber communication; and I propose that an actor-network approach should be investigated as an analytical framework in these cases. I then apply this approach to the case study, using field research conducted with the participants of the FIDAMERICA electronic life history project in Central America. I conclude that an actor-network approach is a fruitful means by which these processes can be both understood and improved.     

Interpretation of tectonic versus magmatic processes for resetting apatite fission track ages in the Niğde Massif, Turkey

A network of 10 OBS operating in continuous recording mode was deployed in June 2003 in the Galicia passive Margin, surrounding the sinking zone of the ‘Prestige’ oil tanker. The OBSs recorded very different signals, including air-gun shots, seismic events, whale vocalizations or noise associated to ships, as well as two sets of atypical seismic signals that are the object of this contribution and can be described as harmonic tremors and short-duration events. Harmonic tremors appear in most sites as intense monochromatic signals lasting for up to 4 h, with coherent polarization and a wide range of amplitudes. Even if they may be recorded at different sites within a time interval, their envelopes are not correlated, suggesting a source origin at the vicinity of each receiver. A time periodicity close to 6 h is observed, suggesting a correlation with the tidal variation. Most OBSs show also a large number of impulsive events of short-duration, between 1 and 2 s, a very regular decrease of amplitude in the signal coda and characteristic frequency spectrum with one or two narrow peaks. As for the tremors, those events are detected only in individual sites, suggesting very local source zones. We favor the interpretation of both seismic features as coming from the resonance of fluid-filled cracks induced by impulsive pressure transients, in agreement with the theoretical model of Chouet [Chouet, B. 1988. Resonance of a fluid-driven crack: radiation properties and implications for the source of long-period events and harmonic tremor. J. Geophys. Res., 93, 4375–4400.]. The observed harmonic tremors would be the result of sustained pressure fluctuations, probably related to the stress variations induced by the tidal change of the oceanic load, while the short duration events are interpreted as the impulse response to the tremor-generating system.     

Small scale study of groundwater flow in a fractured carbonate-rock aquifer at the St-Eustache quarry, Québec, Canada

A small-scale hydrogeological study was conducted in a fractured carbonate-rock aquifer located in a quarry to relate groundwater flow to the fracture network. The field study in the St-Eustache quarry, which integrates structural surveys, well logging and hydraulic tests, showed that the most important features that affect groundwater flow in the sedimentary aquifer are high hydraulic conductivity horizontal bedding planes. Vertical fractures are abundant in the quarry and throughout the region, but they have a minor effect on groundwater flow. To have a significant impact on the flow regime and lead to vertical groundwater flow, the permeability of all vertical joints need to be enhanced compared to what was generally observed at the site. Such an increase in permeability could potentially occur where dissolution and fracturing is more intense or at stress release locations such as near the surface in the quarry.     

Recent rapid salinity rise in three East Antarctic lakes

Research in East Antarctica has shown several recent environmental changes that may be linked to human impacts on climate. In order to detect the influence and context of these changes on coastal aquatic ecosystems we examined lake sediment cores from three lakes in the Windmill Islands, East Antarctica; Beall Lake, Holl Lake and ȁ8Lake Mȁ9. Cores were sectioned at␣2.5 mm intervals. Their diatom species composition was examined to detect changes in lake salinity using a diatom-salinity transfer function, and their algal pigment content was examined to detect photoautotrophic community responses to environmental change. Results showed that Holl Lake originated in a depression exposed by Holocene recession of the continental ice sheet and that Beall Lake and Lake M originated as isolated marine basins formed by changes in relative sea level. A general late Holocene trend of declining lake salinity was evident in all three lakes, interrupted by one short-term high salinity event in Beall Lake. This is consistent with a long-term positive moisture balance. This general decline in salinity has been followed by a remarkable recent rapid increase in salinity in all three lakes in the last few decades. We speculate that this rapid increase in salinity might be linked to changes taking place in the region including feedbacks resulting from decreasing sea ice extent as recorded in the nearby Law Dome ice core, and positive feedbacks in the catchments whereby reduced snow cover has led to decreased albedo, which in turn has caused increased evaporation and sublimation. Collectively these changes have shifted the lakes across a threshold from positive to negative moisture balance. A minor, but not rapid shift in the abundance of diatom pigments relative to pigments from green algae and cyanobacteria was also detected suggesting that some changes in photoautotrophic community composition have occurred. Measurements of modern nutrient levels are also higher than would be expected in Beall Lake and Holl Lake, given the extremely low sediment accumulation rates. This may be associated with a c. 300% increase in the population of Adélie penguins in the Windmill Islands recorded since the 1950s, or may a first signs of a rapid increase in catchment development and associated lake productivity as experienced in Antarctic and Arctic lakes subject to recent rapid regional warming. The most marked feature of the records is the rapid increase in salinity in all three lakes in␣the last few decades, which has occurred in lakes both with and without resident penguin populations.Dominic A. Hodgson and Donna Roberts contributed equally to this work     

Application of empirical and semi-analytical algorithms to MERIS data for estimating chlorophyll a in Case 2 waters of Lake Erie

Lake Erie is biologically the most active lake among the Great Lakes of North America, experiencing seasonal harmful algal blooms (HABs). The early detection of HABs in the Western Basin of Lake Erie (WBLE) requires a more efficient and accurate monitoring tool. Remote sensing is an efficient tool with high spatial and temporal coverage that can allow accurate and timely detection of the HABs. The WBLE is heavily influenced by the surrounding terrestrial ecosystem via rivers such as the Sandusky River and the Maumee River. As a result, the optical properties of the WBLE are influenced by multiple color producing agents (CPAs) such as phytoplankton, colored dissolved organic matter (CDOM), organic detritus, and terrigenous inorganic particles. The diversity of the CPAs and their non-linear interactions makes these waters optically complex, and the task of optical remote sensing for retrieving estimates of CPAs more challenging. Chlorophyll a, which is the primary light harvesting pigment in all phytoplankton, is used as a proxy for algal biomass. In this study, several published remote sensing algorithms and band ratio models were applied to the reflectance data from the full resolution MERIS sensor to remotely estimate chlorophyll a concentrations in the WBLE. Efficiency of the sensor and the algorithms performance were tested through a least squares regression and residual analysis. The results indicate that, among the suite of existing bio-optical models, the Simis semi-analytical algorithm provided the best model results for measures of algal biomass in the optically complex WBLE with R ² of 0.65, RMSE 0.85 μg/l, (n = 71, P < 0.05). The superior results of this model in detecting chlorophyll a are attributed to several factors including optimizing spectral regions that are less sensitive to CDOM and the incorporation of correction factors such as absorption effects due to pure water (a _w), backscatter (b _b) from suspended matter and interference due to phycocyanin (δ), a major accessory pigment in the WBLE.     

Use of sacrificial embankments to minimize bridge damage from scour during extreme flow events

The leading cause of bridge failure has often been identified as bridge scour, which is generally defined as the erosion or removal of streambed and/or bank material around bridge foundations due to flowing water. These scour critical bridges are particularly vulnerable during extreme flood events, and pose a major risk to human life, transportation infrastructure, and economic sustainability. Retrofitting the thousands of undersized and scour critical bridges to more rigorous standards is prohibitively expensive requiring effective yet economical countermeasures. This research tested the efficacy of using approach embankments as intentional sacrificial “fuses” to protect the bridge integrity and minimize damage during large flow events by allowing the streams to access their natural floodplain and reduce channel velocities. This countermeasure concept was evaluated using the Hydrologic Engineering Center’s River Analysis System models. Steady flow models were developed for three specific bridges on two river reaches. Streamflow return period estimators for both river reaches were developed using Bayesian analysis and available United States Geological Survey stream gauge data to evaluate sacrificial embankments under non-stationary climatic conditions. The use of sacrificial embankments was determined to be a cost-effective scour mitigation strategy for bridges with suboptimal hydraulic capacity and unknown or shallow foundations. Additional benefits of sacrificial embankments include reductions in upstream flood stage and velocity.