SEASONAL INORGANIC NITROGEN RELEASE IN ALPINE LAKES ON THE COLORADO WESTERN SLOPE

In the Rocky Mountains, the association of increases in acidic deposition with increased atmospheric loading of sulfate and direct changes in surface water chemistry has been well established. The importance, though, of increased nitrogen (N) deposition in the episodic acidification of alpine lakes and N saturation in alpine ecosystems is only beginning to be documented. In alpine areas of the Colorado Front Range, modest loadings of N in deposition have been associated with leakage of N to surface waters. On the Colorado western slope, however, no leakage of N to surface waters has been reported. A 1995 study that included early season under-ice water samples that were not available in earlier studies showed that there is, in fact, N leakage to surface waters in some western slope basins. Under-ice nitrate (NO^- ₃) concentrations were as high as 10.5 μeq L^-1 and only decreased to detection limits in September. Landscape type appears to be important in leakage of N to surface waters, which is associated with basins having steep slopes, thin soils, and large amounts of exposed bedrock. NO^- ₃ leakage compounds the existing sensitivity to episodic acidification from low acid neutralizing capacity (ANC), which is less than 40 μeq L^-1 in those basins. [Key words: episodic acidification, nitrogen deposition, nitrate, alpine ecosystems, landscape type, Rocky Mountains.]     

Obsessive–compulsive disorder (OCD): Gendered metaphors,blogs and online forums

In order to understand social recovery from mental illness, it is important to examine the role played by social space, including virtual space. This article examined blogs and online forums for people with obsessive–compulsive disorder (OCD). In particular, it addressed gender differences in the metaphors used by men and women in these virtual spaces. Empirical data illustrated that, in general, women are more likely to frame their experiences of OCD as a journey, whereas men are more likely to frame them as a battle. Use of these different metaphors has potential implications for social recovery.     

Radar observations of asteroid 1999 JM8

Abstract— We report results of delay‐Doppler observations of 1999 JM8 with the Goldstone 8560 MHz (3.5 cm) and Arecibo 2380 MHz (13 cm) radars over 18 days in July‐August 1999. The images place thousands of pixels on the asteroid and achieve range resolutions as fine as 15 m/pixel. The images reveal an asymmetric, irregularly shaped object with a typical overall dimension within 20% of 7 km. If we assume that 1999 JM8's effective diameter is 7 km, then the absolute magnitude, 15.15, and the average Goldstone radar cross section, 2.49 km², correspond to optical and radar albedos of 0.02 and 0.06, establishing that 1999 JM8 is a dark object at optical and radar wavelengths. The asteroid is in a non‐principal axis spin state that, although not yet well determined, has a dominant periodicity of ?7 days. However, images obtained between July 31 and August 9 show apparent regular rotation of features from day to day, suggesting that the rotation state is not far from principal axis rotation. 1999 JM8 has regions of pronounced topographic relief, prominent facets several kilometers in extent, numerous crater‐like features between ?100 m and 1.5 km in diameter, and features whose structural nature is peculiar. Arecibo images provide the strongest evidence to date for a circular polarization ratio feature on any asteroid. Combined optical and radar observations from April 1990 to December 2000 permit computation of planetary close approach times to within ± 10 days over the interval from 293 to at least 2907, one of the longest spans for any potentially hazardous asteroid. Integration of the orbit into the past and future shows close approaches to Earth, Mars, Ceres, and Vesta, but the probability of the object impacting Earth is zero for at least the next nine centuries.     

Towards improved ground models for slope instability evaluations through better characterization of sediment-hosted gas-hydrates

ABSTRACT Recently developed effective stress-controlled geophysical property models are used in passive-margin slope instability analyses including simulated earthquake motion. The pressure–temperature (P–T) history of sediment-hosted gas hydrate may significantly alter the geophysical property profile of the sediment column (e.g. metastable cement or increased pore pressures). This can result in significant amplification of earthquake ground motion, and thus seabed instability, where hydrates are present. Published studies suggest destabilization of these high-pressure/low-temperature sediment-hosted hydrates could trigger catastrophic slope failures with consequent liberation of 'greenhouse' gases and significant effects on global climate. To provide improved ground models for slope instability analyses we are investigating the influence of P–T history on hydrate distribution in sediments through the development of laboratory techniques to enable geophysical quantification of hydrate morphology and fabric on hydrate stability.     

Urban parks as shared spaces? The utility of alert distances as indicators of avian tolerance of humans in Stirling, Scotland

Urban avian foraging is strongly affected by approaching people. Avian alert distances, the instant of a bird's appraisal of human intrusion, have not been studied in a comparative mode for passerines, despite their prominent ecological importance in parks. Alert distances for 13 passerines were examined in parks in Stirling, Scotland, using an innovative approach emphasizing human behaviour and periods between alert and flight distances, termed alert periods. Larger species were less tolerant of humans, although attracted to human wastes. Alert distances also varied according to vegetation variation. Park design may use alert distances to plan vegetation layout as well as reduce disturbing human behaviour.     

The effect of asynchronism on wind-driven mass transfer rates in the polars

An asynchronous magnetic white dwarf affects the rate of orbital evolution in AM Herculis binaries. An over-synchronous star leads to a positive orbital magnetic torque which reduces the rate of shrinkage of the secondary star's Roche lobe, and hence reduces the mass transfer rate. An opposing effect occurs as a result of the orbital angular momentum loss via secondary mass transfer in the absence of an accretion disc. The modification of the magnetic braking-driven synchronous mass transfer rate is calculated for a range of degrees of asynchronism, and its effect is compared at different orbital periods.     

Mass data processing of time series Landsat imagery: pixels to data products for forest monitoring

Free and open access to the Landsat archive has enabled the implementation of national and global terrestrial monitoring projects. Herein, we summarize a project characterizing the change history of Canada’s forested ecosystems with a time series of data representing 1984–2012. Using the Composite2Change approach, we applied spectral trend analysis to annual best-available-pixel (BAP) surface reflectance image composites produced from Landsat TM and ETM+ imagery. A total of 73,544 images were used to produce 29 annual image composites, generating ～400 TB of interim data products and resulting in ～25 TB of annual gap-free reflectance composites and change products. On average, 10% of pixels in the annual BAP composites were missing data, with 86% of pixels having data gaps in two consecutive years or fewer. Change detection overall accuracy was 89%. Change attribution overall accuracy was 92%, with higher accuracy for stand-replacing wildfire and harvest. Changes were assigned to the correct year with an accuracy of 89%. Outcomes of this project provide baseline information and nationally consistent data source to quantify and characterize changes in forested ecosystems. The methods applied and lessons learned build confidence in the products generated and empower others to develop or refine similar satellite-based monitoring projects.