ALBERT

Beschreibung: Author(s): N. Satchell, J. D. S. Witt, M. G. Flokstra, S. L. Lee, J. F. K. Cooper, C. J. Kinane, S. Langridge, and G. Burnell Though superconductivity and ferromagnetism are traditionally seen as competing phenomena, when representative materials are artificially juxtaposed, a trove of unusual physics is found at the interface. For example, in a Nb/Er bilayer, adjusting the magnetic state of the Er at remanence changes the shape of the resistivity transition in the Nb, controlling its superconducting T c . Thus the Nb “remembers” the field applied to the Er, which could be the basis of energy-efficient data storage in cryogenic s u p e r c o n d u c t i n g s p i n t r o n i c s . [Phys. Rev. Applied 7, 044031] Published Fri Apr 28, 2017

Beschreibung: An improved understanding of sources and timing of water and nutrient fluxes associated with urban stream restoration is critical for guiding effective watershed management. We investigated how sources, fluxes, and flowpaths of water, carbon (C), nitrogen (N), and phosphorus (P) shift in response to differences in stream restoration and sanitary infrastructure. We compared a restored stream with 3 unrestored streams draining urban development and stormwater management over a 3 year period. We found that there was significantly decreased peak discharge in response to precipitation events following stream restoration. Similarly, we found that the restored stream showed significantly lower monthly peak runoff (9.4 ± 1.0 mm d−1) compared with two urban unrestored streams (ranging from 44.9 ± 4.5 to 55.4 ± 5.8 mm d−1) draining higher impervious surface cover. Peak runoff in the restored stream was more similar to a less developed stream draining extensive stormwater management (13.2 ± 1.9 mm d−1). Interestingly, the restored stream exported most carbon, nitrogen, and phosphorus loads at relatively lower streamflow than the 2 more urban streams, which exported most of their loads at higher and less frequent streamflow. Annual exports of total carbon (6.6 ± 0.5 kg ha−1 yr−1), total nitrogen (4.5 ± 0.3 kg ha−1 yr−1), and total phosphorus (161 ± 15 g ha−1 yr−1) were significantly lower in the restored stream compared to both urban unrestored streams (p 〈 0.05) and similar to the stream draining stormwater management. Although stream restoration appeared to potentially influence hydrology to some degree, nitrate isotope data suggested that 55 ± 1 % of the nitrate in the restored stream was derived from leaky sanitary sewers (during baseflow), similar to the unrestored streams. Longitudinal synoptic surveys of water and nitrate isotopes along all 4 watersheds suggested the importance of urban groundwater contamination from leaky piped infrastructure. Urban groundwater contamination was also suggested by additional tracer measurements including fluoride (added to drinking water) and iodide (contained in dietary salt). Our results suggest that integrating stream restoration with restoration of aging sanitary infrastructure can be critical to more effectively minimize watershed nutrient export. Given that both stream restoration and sanitary pipe repairs both involve extensive channel manipulation, they can be considered simultaneously in management strategies. In addition, ground water can be a major source of nutrient fluxes in urban watersheds, which has been less considered compared with upland sources and storm drains. Goundwater sources, fluxes, and flowpath should also be targeted in efforts to improve stream restoration strategies and prioritize hydrologic "hot spots" along watersheds where stream restoration is most likely to succeed.