Abstract--This is a preliminary report of results of a study wherein vegetation has been cut along the stream bank of a 22-acre watershed on the Coweeta Experimental Forest. Previous measurements on this forest have shown that complete removal of vegetation results in notable gains in water yield because of a reduction in transpiration. The cutting of riparian growth has also resulted in an increase in yield of sufficient magnitude to be significant in water-resource management.Preliminary examination of the data immediately following cutting shows a virtual elimination of the diurnal fluctuation during the growing season. This indicates that the vegetation immediately adjacent to the stream is making appreciable demands upon groundwater supplies contributing directly to streamflow.It can be concluded, therefore, that important gains in water yield during the growing season in the southern Appalachian region may be realized with relatively little effort by eliminating the transpiration draft of riparian vegetation. This procedure can be of much practical value during drought years for municipal and industrial watersheds, when even small increases in yield are of unusual importance.Diurnal variations in runoff have long been associated with the combined draft of evaporation and transpiration upon water in streams and the adjacent groundwater aquifer. This evapotranspiration factor has been termed "consumptive use" by BLANEY, TAYLOR, and YOUNG [see "References" at end of paper, 1930]. Except for water losses through deep seepage, it is almost entirely responsible for the difference between precipitation and runoff within the water year.

Augmented reality and visual reality (AR and VR) microdisplays require micro light emitting diodes (μLEDs) with an ultrasmall dimension (≤5 μm), high external quantum efficiency (EQE), and narrow spectral line width. Unfortunately, dry etching which is the most crucial step for the fabrication of μLEDs in current approaches introduces severe damages, which seem to become an insurmountable challenge for achieving ultrasmall μLEDs with high EQE. Furthermore, it is well-known that μLEDs which require InGaN layers as an emitting region naturally exhibit significantly broad spectral line width, which becomes increasingly severe toward long wavelengths such as green. In this paper, we have reported a combination of our selective overgrowth approach developed very recently and epitaxial lattice-matched distributed Bragg reflectors (DBRs) embedded in order to address all these fundamental issues. As a result, our μLEDs with a diameter of 3.6 μm and an interpitch of 2 μm exhibit an ultrahigh EQE of 9% at ∼500 nm. More importantly, the spectral line width of our μLEDs has been significantly reduced down to 25 nm, the narrowest value reported so far for III-nitride green μLEDs.

No abstract

The primary successions of saltmarsh vegetation in 2 managed realignment sites in the Blackwater estuary (SE England), Tollesbury and Abbotts Hall, began with domination by the opportunistic annual species Salicornia europaea and Suaeda maritima. These species were gradually replaced by perennial species at the higher elevations, and a vertical zonation of dominant species was established in the order Salicornia europaea/Spartina anglica, Puccinellia maritima, Atriplex portulacoides and Elytrigia atherica, from low to high saltmarsh. Suaeda maritima became rarer and patchily distributed. Ordination analysis confirmed that after 12 yr the new saltmarsh at Tollesbury was similar to the adjacent ancient saltmarsh. At Abbotts Hall the broadly similar successional sequence took only 5 yr. These were not facilitated successions-plants increasing the elevation of the sediment-because little sediment had accreted. Instead these were characteristic of tolerancetype successions, with the early opportunistic species having no apparent facilitative or inhibitive effect on the perennial species that arrived later and outcompeted them. If land at the appropriate elevation is provided by coastal realignment, saltmarsh develops to resemble the vegetation structure of ancient saltmarshes rapidly, with positive prospects for saltmarsh restoration. However, the erosion of saltmarsh vegetation that developed in historical realignment sites indicates that this benefit may be relatively short-term. Hence, long-term saltmarsh creation must also account for the processes causing saltmarsh erosion.

To fully exploit the advantages of GaN for electronic devices, a critical electric field that approaches its theoretical value (3 MV/cm) is desirable but has not yet been achieved. It is necessary to explore a new approach toward the intrinsic limits of GaN electronics from the perspective of epitaxial growth. By using a novel two-dimensional growth mode benefiting from our high-temperature AlN buffer technology, which is different from the classic two-step growth approach, our high-electron-mobility transistors (HEMTs) demonstrate an extremely high breakdown field of 2.5 MV/cm approaching the theoretical limit of GaN and an extremely low off-state buffer leakage of 1 nA/mm at a bias of up to 1000 V. Furthermore, our HEMTs also exhibit an excellent figure-of-merit (V br 2/R on,sp) of 5.13 × 108 V2/Ω·cm2.