How does the U-shaped potential close above the acceleration region? A study using Polar data

We present a statistical study of Polar electric field observations using auroral oval passes over Scandinavia above the acceleration region. We are especially interested in seeing whether we can find large perpendicular electric fields associated with an upward extended classical U-shaped potential drop for these passes, during which Polar is in the northern hemisphere usually at about 4 R_E altitude. We also use Polar magnetic field data to infer the existence of a field-aligned current (FAC) and conjugate ground-based magnetometers (the IMAGE magnetometer network) to check whether the event is substorm-related or not. We find several events with a FAC but only weak perpendicular electric fields at Polar. In those rare cases where the Polar electric field was large, its direction was mostly found to be incompatible with the U-shaped potential model, or it was associated with disturbed conditions (substorms), where one cannot easily distinguish between inductive and static perpendicular electric fields. We found only two cases which are compatible with the upward extended U-shaped potential picture, and even in those cases the potential value is quite small (1–kV). To check the validity of the analysis method we also estimate the perpendicular electric field on the southern hemisphere, where Polar flies within or below the acceleration region, and we found a large number of inverted-V-type signatures as expected from previous studies. To explain the lack of perpendicular electric fields at high altitudes we suggest an O-shaped potential model instead of the U-shaped one.     

Valuing multi-attribute marine water quality

The marine environment provides many goods and services that depend on the quality of coastal waters. In this paper, we represent water quality by three different attributes, coastal cod stock level, bathing water quality, and biodiversity level, and carry out a choice experiment among residents on the Swedish west coast to estimate the economic benefits of improved coastal water quality. We find that respondents have high levels of environmental concern and that substantial values are at stake. The highest values were placed on preventing further depletion of marine biodiversity and to improve Swedish cod stocks.     

Making the ecosystem approach operational—Can regime shifts in ecological- and governance systems facilitate the transition?

Effectively reducing cumulative impacts on marine ecosystems requires co-evolution between science, policy and practice. Here, long-term social–ecological changes in the Baltic Sea are described, illustrating how the process of making the ecosystem approach operational in a large marine ecosystem can be stimulated. The existing multi-level governance institutions are specifically set up for dealing with individual sectors, but do not adequately support an operational application of the ecosystem approach. The review of ecosystem services in relation to regime shifts and resilience of the Baltic Sea sub-basins, and their driving forces, points to a number of challenges. There is however a movement towards a new governance regime. Bottom-up pilot initiatives can lead to a diffusion of innovation within the existing governance framework. Top-down, enabling EU legislation, can help stimulating innovations and re-organizing governance structures at drainage basin level to the Baltic Sea catchment as a whole. Experimentation and innovation at local to the regional levels is critical for a transition to ecosystem-based management. Establishing science-based learning platforms at sub-basin scales could facilitate this process.     

Discrimination of topaz rhyolites by major-element composition: a statistical routine for geochemical exploration

The recognition of topaz-bearing, calc-alkaline, and peralkaline rhyolites at an early stage of an exploration program may be of both geologic interest and of economic significance due to the different mineral deposits characteristically associated with each of these rock suites. Such discrimination could result in better definition of target areas and commodities to explore within a selected region.A geochemical database of major element analyses of calc-alkaline, peralkaline (comendites), and topaz rhyolites from western North America was assembled. Multiple discriminant function analysis assigned each sample statistically to the calc-alkaline, topaz, or peralkaline groups, using only major element composition. The assignment correctly identified 90% of the rhyolites as members of the groups to which they actually belong. In effect, then, major-element composition can serve as a proxy for fluorine content either when no fluorine analysis is available or when it is suspected that fluorine was not preserved in the rock due to its loss during emplacement or subsequent devitrification.We have included a simplified procedure to use our discrimination model to identify silicic rocks of unknown affiliation. This model makes it possible to evaluate the economic potential of both new or previously explored areas by analyzing data files containing major-element chemical analyses.     

Fate of Pesticides and Their Transformation Products: First Flush Effects in a Semi‐Arid Catchment

Although it is known for many years, that transformation products (TPs) of pesticides are often more persistent, mobile, and sometimes more toxic than the parent compound, former catchment scale studies of substance release and flushing effects focused only on the parent compound. In this study, four river points were sampled in the Hula Valley, Israel, and samples were analyzed in the lab for chlorpyrifos (CP) and endosulfan residues (including transformation products; TPs). Sampling results of the first rainfall in autumn 2009 identified a strong release of most substances to the rivers. First flush effects of these substances were assessed regarding the risk for drinking water supply and ecology, like fresh water invertebrates and fish. Although, these substances were found in Jordan River water during the first significant rainfall the observed levels are below international drinking water guideline values with no adverse effects on human health in the region. However, the observed CP and chlorpyrifos oxon (CPO) levels are above the acute toxicity for fresh water invertebrates and fish. The study shows that the Hula Valley was an important source of pesticides and TPs at the Upper Jordan River basin and that substance flushing is extremely important for pesticides‐monitoring campaigns.     

A Review of “Perilous Place,Powerful Storms: Hurricane Protection in Coastal Louisiana”

Based on a large-scale household survey conducted in Nanjing in 2005, this study examines housing differentiation between and within groups defined by different socioeconomic characteristics and analyzes institutional and market determinants of housing differentiation under market transition. It is worth noting that, although the degree of housing differentiation between different socioeconomic groups is high, the differentiation within each group is even more significant. This suggests an intensified housing differentiation in the Chinese city. Institutions inherited from the socialist period and the emerging market mechanisms are intertwined to contribute to housing differentiation after the introduction of housing reform. In the postreform era, whereas some institutional factors were weakened, other institutional factors such as the hukou system and the work unit system continue to be significant. Furthermore, similar to other postsocialist countries, the pattern of housing inequality in prereform China remains and even consolidates after economic reforms; that is, vested groups continue to enjoy better housing conditions under a market economy, and the disadvantaged groups are entrapped in a housing predicament. Nevertheless, market factors have also become decisive, which is mainly reflected in the significant housing differentiation between groups categorized by educational attainment and household income.     

GEOMORPHIC RESPONSE TO WILDFIRE IN AN ARID WATERSHED,CROW CANYON,NEVADA

On August 28, 1981, the Crow Canyon drainage basin in central Nevada was burned by a lightning-generated wildfire that destroyed the vegetation cover consisting primarily of juniper trees, sagebrush, and desert grasses. The geomorphic impact of the wildfire was assessed on the basis of aerial photography, measurements of sediment movement on hillslopes using charred tree trunks as erosion indicators, and surveys of the valley floor, axial channel, and alluvial fan. Aerial photographs indicate the valley floor was untrenched prior to the fire. The combination of foliage destruction and heavy runoff in the spring following the wildfire initiated channel downcutting that has now reached as much as 3.9 m in depth. Entrenchment of the valley-fill in the lower 2.2 km of the drainage network produced as much as 48, 142 m³ of sediment. Much of the channel incision occurred during 1982 and 1983, years characterized by above-normal precipitation. Approximately 17,608 m³ of sediment were deposited on a preexisting alluvial fan at the mouth of the basin. Following initial channel entrenchment and deposition on the fan, a spatially out-of-phase episode of channel cutting was initiated on the fan apex, a process that is redistributing sediment down-fan. Thus, one geomorphic disturbance has produced two discrete depositional events on the fan. Moreover, the geomorphic instability was still evident over a decade after the wildfire. [Key words: wildfire, degradation, channel entrenchment, soil erosion, complex-response.]