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Mass wasting in forested mountain topography
As the demands for forest products increase, additional timber harvesting operations can be expected on steep mountainous terrain, The resulting disruption of natural slope stability by man's disturbances (roadbuilding, logging and vegetative manipulation, etc.) may also accelerate mass movement processes in this terrain. Swanston (1969) defines mass movement as "., .the slow to rapid downslope movement of large masses of earth material (soil, rock and forest debris) of varying water content, primarily under the force of gravity". Earlier, Popov (1963) quoted Pogrebov's definition of mass wasting as " •.. movement of a rock mass downward under the pressure of gravity, commonly associated with the activity of surface and ground water". As a dominant form of erosion on mountainous lands in the Pacific Northwest, mass movement may reduce site productivity by removing soil material and lowering the nutrient capital; cause damage to roads, other improvements and scenic values; lead to serious channel degradation and scoured channel banks; contaminate water quality with increased sediment loads, turbidities and dissolved chemical content; shorten the life span of reservoirs due to excessive siltation, and impair fish habitat through increased sediment in spawning gravels and blockage of fish passage by landslides (Brown, 1973; Swanston and Dyrness, 1973). Accelerated mass movement is probably the most serious problem facing land managers in areas characterized by steep slopes and heavy rainfall. The objective of this paper is to review and summarize the present knowledge about mass movement processes on mountainous forest lands, This review will emphasize problems associated with man's activities and may provide professional hydrologists and land managers with information that can be applied in making effective management decisions, In addition, several types of studies will be identified from which an improved understanding of mass movement processes may be obtained
Spinor Bose-Einstein condensates
An overview on the physics of spinor and dipolar Bose-Einstein condensates
(BECs) is given. Mean-field ground states, Bogoliubov spectra, and many-body
ground and excited states of spinor BECs are discussed. Properties of
spin-polarized dipolar BECs and those of spinor-dipolar BECs are reviewed. Some
of the unique features of the vortices in spinor BECs such as fractional
vortices and non-Abelian vortices are delineated. The symmetry of the order
parameter is classified using group theory, and various topological excitations
are investigated based on homotopy theory. Some of the more recent developments
in a spinor BEC are discussed.Comment: To appear in Physics Reports. The PDF file with high resolution
figures is available from the following website:
http://cat.phys.s.u-tokyo.ac.jp/publication/review_of_spinorBEC.pd