Phase differences between luminosity and velocity measurements of the acoustic modes

With two photometric stations (Tenerife and Baja California) the luminosity p-mode spectrum at different wavelengths has been identified. After a coherence analysis between data from both stations to verify the solar origin of the peaks identified in luminosity, a comparative study with simultaneous velocity measurements (obtained at Tenerife only) has also been made. As a result the frequency dependence of the phase difference between luminosity and velocity p-modes has been obtained that is interpreted in terms of a nonadiabatic behaviour of the solar atmosphere. The amplitude ratios between luminosity and velocity p-modes have also been obtained. All these results are compared with theoretical expectations.     

Diversity and distribution of landscape trees in the compact Asian city of Taipei

The promotion and preservation of biodiversity in urban areas remains scant, especially in Asian cities. This study focuses on spatial pattern and diversity of landscape trees in compact Taipei. Aggregate species diversity of three urban habitats (streets, urban parks and riverside parks) exceeded the countryside's secondary forests. Urban parks with site heterogeneity and multiple functions accommodate the highest richness, and streets with acute site limitations the poorest represented by popular native species. More affinities exist between urban and riverside parks. Low diversity in riverside parks echoes natural site constraints and primary use for river discharge and flood control. The compact urban form has not stifled species diversity and spatial variability of urban forests. Development history and park area have no significant relationship with species diversity. Understanding species composition in urban ecosystems could frame conservation strategies to augment species richness, appropriate site selection, habit preservation and wildlife recruitment.     

Uncertainty assessment of a process-based integrated catchment model of phosphorus

Despite the many models developed for phosphorus concentration prediction at differing spatial and temporal scales, there has been little effort to quantify uncertainty in their predictions. Model prediction uncertainty quantification is desirable, for informed decision-making in river-systems management. An uncertainty analysis of the process-based model, integrated catchment model of phosphorus (INCA-P), within the generalised likelihood uncertainty estimation (GLUE) framework is presented. The framework is applied to the Lugg catchment (1,077 km²), a River Wye tributary, on the England–Wales border. Daily discharge and monthly phosphorus (total reactive and total), for a limited number of reaches, are used to initially assess uncertainty and sensitivity of 44 model parameters, identified as being most important for discharge and phosphorus predictions. This study demonstrates that parameter homogeneity assumptions (spatial heterogeneity is treated as land use type fractional areas) can achieve higher model fits, than a previous expertly calibrated parameter set. The model is capable of reproducing the hydrology, but a threshold Nash-Sutcliffe co-efficient of determination (E or R ²) of 0.3 is not achieved when simulating observed total phosphorus (TP) data in the upland reaches or total reactive phosphorus (TRP) in any reach. Despite this, the model reproduces the general dynamics of TP and TRP, in point source dominated lower reaches. This paper discusses why this application of INCA-P fails to find any parameter sets, which simultaneously describe all observed data acceptably. The discussion focuses on uncertainty of readily available input data, and whether such process-based models should be used when there isn’t sufficient data to support the many parameters.     

Vadose zone tritium tracer test to estimate aquifer recharge from irrigated areas

Environmental tracers, such as tritium, have generally been used to estimate aquifer recharge under natural conditions. A tritium tracer test is presented for estimating recharge under semi‐arid and irrigated conditions. The test was performed along 429 days (June 2007–August 2008) on an experimental plot located in SE Spain with drip irrigation and annual row crops (rotation of lettuce and melon), in which common agricultural practices were followed in open air. Tritiated water was sprinkled (simulated rainfall) over the plot, soil cores were taken at different depths and a liquid scintillation analyzer was used to measure tritium concentration in soil water samples. Tritium transport, as liquid or vapor phase, was simulated with the one‐dimensional numerical code SOLVEG. Simulations show that the crop water use was below potential levels, despite regular irrigation. Continuous high water content in soil promoted a great impact of rainfall events on the aquifer recharge. The results obtained from tritium tracer test have been compared with other independent recharge assessment, soil water balance method, to evaluate the reliability of the first one. Total recharge from tracer test was 476 mm for the October 2007–September 2008 period versus 561 mm from soil water balance method for the same period, which represents 37.1% and 43.7% of the applied water (1284 mm, irrigation + precipitation), respectively. Copyright © 2012 John Wiley & Sons, Ltd.     

Heat, chloride, and specific conductance as ground water tracers near streams

Commonly measured water quality parameters were compared to heat as tracers of stream water exchange with ground water. Temperature, specific conductance, and chloride were sampled at various frequencies in the stream and adjacent wells over a 2-year period. Strong seasonal variations in stream water were observed for temperature and specific conductance. In observation wells where the temperature response correlated to stream water, chloride and specific conductance values were similar to stream water values as well, indicating significant stream water exchange with ground water. At sites where ground water temperature fluctuations were negligible, chloride and/or specific conductance values did not correlate to stream water values, indicating that ground water was not significantly influenced by exchange with stream water. Best-fit simulation modeling was performed at two sites to derive temperature-based estimates of hydraulic conductivities of the alluvial sediments between the stream and wells. These estimates were used in solute transport simulations for a comparison of measured and simulated values for chloride and specific conductance. Simulation results showed that hydraulic conductivities vary seasonally and annually. This variability was a result of seasonal changes in temperature-dependent hydraulic conductivity and scouring or clogging of the streambed. Specific conductance fits were good, while chloride data were difficult to fit due to the infrequent (quarterly) stream water chloride measurements during the study period. Combined analyses of temperature, chloride, and specific conductance led to improved quantification of the spatial and temporal variability of stream water exchange with shallow ground water in an alluvial system.     

Virtualizing Los Angeles: Pierre Levy, <Emphasis Type="Italic">The Shield</Emphasis>, and http://theshieldrap.proboards45.com/

I explore how Pierre Levy’s virtualization works between actual places, television, and the Internet by referencing the real landscapes of Los Angeles, the visualized landscapes of the FX network television show The Shield, and the cyberscapes of . Unlike current Deleuzean-based theories of visualization that privilege the passage from the virtual to the actual, Levy focuses instead on how virtualization moves back from the real/actual toward the virtual. I argue that this philosophical reversal illustrates the way in which the virtual constitutes the viewer/consumer and thus functions to resituate the virtual within the body through the use of digital landscapes. I further argue, using The Shield as the modality, that the virtual is necessarily an element of the very body which it serves to constitute because the virtual is indeed an essential part of the determination of the geographies of every concrete biocultural body. My example of The Shield becomes the means by which we can bring the force of the virtual, in the form of web-based landscapes, to bear on our experience. I use the show and its Internet counterpart as the catalyst for an expansion of the margin of indetermination constitutive of our technically-facilitated embodiment. By further relating the TV show to our seemingly playful interactions with the digital landscape, I explore how this interaction crosses multiple scales and multiple viewing modalities and further blurs the borders of experiential reality and the visualization of fantasized landscapes. The Shield’s representations of the Los Angeles landscape become embodied experiences for viewers of the show and by virtualizing the real landscapes of Los Angeles and their televisual counterparts, allows consumers to know the spaces of the city through their virtual experience of place as imagined by the website and its members. Thus, I show how Levy’s virtualization theories can be used to specify the virtual dimension constitutive of human experience.     

The impact of sulfuric acid on element migration and mineralogy of compacted clays: pH 1.0 to −3.0

The transport of H₂SO₄ (at pH = 1.0, −1.0 and −3.0) through two mineralogically different compacted clays (Kc and Km) was examined using single-reservoir diffusion cells with constant source concentrations. At the end of the 216 day test period, geochemical analyses indicated increased depth of acid diffusion with increased reservoir acidity for both Kc and Km cells. Elevated Ca, Al, Fe and Si concentrations were associated with decreased pH values in all cells. XRD results showed that these elevated concentrations corresponded to the loss of carbonate and montmorillonite peaks and decreased peak intensities for illite and kaolinite in the Kc and Km pH −1.0 and −3.0 Km cells. Moreover, Si X-ray absorption near-edge structure (XANES) indicated dissolution of the phyllosilicate phases, a relative increase in the amount of quartz, and the potential formation of an amorphous silica phase. The results of this study showed that, despite the extreme pH values considered, movement of H₂SO₄ solutions with pH < 1.0 may be greatly retarded in the presence of a strongly neutralizing mineral phase, such as dolomite, within the clay.     

Revealing the “fingerprints” of the magnetic precursor of C-shocks

We present the first C-shock and radiative transfer model that calculates the evolution of the line profiles of neutral and ion species like SiO, H¹³CO⁺ and HN¹³C for different flow times along the propagation of the shock through the unperturbed gas. We find that the line profiles of SiO characteristic of the magnetic precursor stage have very narrow linewidths and are centered at velocities close to the ambient cloud velocity, as observed toward the young shocks in the L1448-mm outflow. Consistently with previous works, our model also reproduces the broad SiO emission detected in the high velocity gas in this outflow, for the downstream postshock gas in the shock. This implies that the different velocity components observed in L1448-mm are due to the coexistence of different shocks at different evolutionary stages.     

Linking the Abundance of Estuarine Fish and Crustaceans in Nearshore Waters to Shoreline Hardening and Land Cover

Human alteration of land cover (e.g., urban and agricultural land use) and shoreline hardening (e.g., bulkheading and rip rap revetment) are intensifying due to increasing human populations and sea level rise. Fishes and crustaceans that are ecologically and economically valuable to coastal systems may be affected by these changes, but direct links between these stressors and faunal populations have been elusive at large spatial scales. We examined nearshore abundance patterns of 15 common taxa across gradients of urban and agricultural land cover as well as wetland and hardened shoreline in tributary subestuaries of the Chesapeake Bay and Delaware Coastal Bays. We used a comprehensive landscape-scale study design that included 587 sites in 39 subestuaries. Our analyses indicate shoreline hardening has predominantly negative effects on estuarine fauna in water directly adjacent to the hardened shoreline and at the larger system-scale as cumulative hardened shoreline increased in the subestuary. In contrast, abundances of 12 of 15 species increased with the proportion of shoreline comprised of wetlands. Abundances of several species were also significantly related to watershed cropland cover, submerged aquatic vegetation, and total nitrogen, suggesting land-use-mediated effects on prey and refuge habitat. Specifically, abundances of four bottom-oriented species were negatively related to cropland cover, which is correlated with elevated nitrogen and reduced submerged and wetland vegetation in the receiving subestuary. These empirical relationships raise important considerations for conservation and management strategies in coastal environments.     

Landslide-hazard mapping through multi-technique activity assessment: an example from the Betic Cordillera (southern Spain)

Landslide hazard in a region limited to data from a regional scale about triggering factors is assessed via cross tabulation between determining factors and landslides with recent activity. Firstly, landslide susceptibility was evaluated and validated through a bivariate statistical method between the previously identified stability conditioning factors and the mapped landslides. In this way, the most susceptible areas for assessing landslide hazards were selected. The main problem to solve in this type of research is the landslide activity. For this purpose, several techniques were applied: news reports, differential interferometric synthetic aperture radar, digital photogrammetry, light detection and ranging, photointerpretation, and dendrochronology. Both the strong and weak points of these techniques are also mentioned. The landslide return period was computed via the association between landslide activity and triggering factors, in this case annual rainfall. Finally, landslide hazard was mapped solely based on landslides with recent activity and their computed return period. The relationship between landslide occurrence and triggering factors shows that, according to both the considered assumptions and the observations made, deep-seated landslides are triggered or reactivated together with superficial landslides once every 18 years, while superficial landslides as flows or falls occur once every 5 years. The results show that there is generally a low landslide hazard in the study zone, especially when compared to landslide susceptibility. This means that landslides are mainly dormant from a natural evolution point of view, but could be reactivated as a result of geomorphological, climate, or human changes. In any case, the landslide hazard is successfully assessed, with a prediction of a 6% annual probability of a high hazard in 5% of the area, intersecting with the main infrastructures of the region; thus, control strategies are justified in order to avoid damage in extraordinary rainfall periods.