17,931 research outputs found
Development, construction and testing of an ultrahigh vacuum dc sputtering system Final report
Design and performance of ultrahigh vacuum system for direct current sputtering electrode
Ecology of fishes in Upper Newport Bay, California: seasonal dynamics and community structure
A total of 366 bimonthly (January 1978-January 1979) samples taken with six types of gear (otter trawl, gill net, bag seine, small seine, drop net, square enclosure - all
with replication except the gill net) at four stations in
upper Newport Bay, California yielded 51,816 fishes belonging to 46 species and weighing over 353 kg. Atherinops affinis (topsmelt) was the most abundant species accounting for 76% of total individuals. Seven species, all of low trophic levels, made up over 97% of the total catch. Mugil cephalus (striped mullet) ranked first in biomass (= 36% of the total) with six species accounting for more than 80% of the total biomass. The largest number of individuals (71%) was collected with the bag seine, the greatest number of species (35) was captured with the otter trawl and the largest percentage of the biomass (56%)was obtained with the gill net. Species richness, number of individuals and biomass were lowest in January (1978 or 1979) or March and highest in July (numbers, biomass) or September (species). Bimonthly diversity (H') values ranged from 0.48 to 2.17 (overall value 1.05) and tended to be inversely related to abundance levels. Species richness was greatest at Station 4 (the lowermost station) and least at Station 1 (the uppermost station). Numbers of individuals and biomass peaked at Station 2 and reached lowest levels at Station 1.
Length-frequency analysis of six of the most abundant
species indicated utilization of the upper bay by two or
more stages in the life history of these species.
More than 92,000 eggs belonging to seven taxa and an
unknown category and 426 larvae from 20 taxa were collected
with a 0.5 m net mounted on an epibenthic sled during the
same bimonthly periods and at the same stations as the
juvenile/adult samples. Most of the eggs were collected at
Station 2 in May with the numbers overwhelmingly dominated
by those of Anchoa compressa (deepbody anchovy) (99.7% of
total numbers). The most abundant larva was that of
Clevelandia ios (arrow goby). Nearly 60% of the total
larval catch was made up of members of the family Gobiidae.
Larval taxa and individuals were fewest in January (1978).
The number of taxa was highest in March, September and
January (1979) whereas larval numbers peaked in May. The
number of taxa and of individual larvae varied only slightly
among the four stations.
Asymptotic species accumulation curves indicated adequate sampling of juvenile/adult fishes. Cluster analysis
produced eight species groups of resident and periodic
species that variously utilize the three main habitats
(channel, inshore, pannes) in the upper bay. Species
richness and abundance were positively correlated with both
temperature and salinity. Temperature, salinity and depth
of capture were frequently correlated with individual species abundances and were used in combination to partially explain the spatial utilization of species and species groups.
The upper bay fish community is important and worthy of
preservation for at least three reasons: 1) it contains
species assemblages not duplicated in any other coastal
environment; 2) it contains life history stages of a
variety of coastal fish species; and 3) it contains large
populations of small, low-trophic level species and juveniles of other species which serve as forage for larger, predatory species that are frequently of economic importance. Members of the fish community respond noticeably to altered environmental conditions such as the heavy rainfall (and accompanying low salinity and high turbidity) that occurred during the early months of 1978. The short and long term, as yet often unpredictable, fluctuations in the populations emphasize the need for periodic monitoring and for the development of a mathematical model of the fish community if it is to be thoroughly understood and properly managed. (102pp.
Pressure dependence of phase transitions in the quasi one-dimensional metal-insulator transition system beta-Na1/3V2O5
The pressure dependence of phase transitions in the quasi one-dimensional
vanadium oxide -NaVO has been studied by magnetic
susceptibility and electrical resistivity measurements. The pressure dependence
of the various transition temperatures is quite differently. The transition at
T=240 K, previously reported and attributed to ordering on Na sites, and a
second transition at K, reported here for the first time and
attributed to a further increase of order on Na sites, are almost independent
of pressure. On the other hand, the metal-insulator (MI) transition at
K shifts to lower temperatures, while the magnetic transition at
K shifts to higher temperatures with increasing pressure. We discuss
the different pressure dependencies of and in terms of
increasing interchain coupling and the MI transition to be of Peierls type.Comment: 5 pages, 5 figure
Majorization criterion for distillability of a bipartite quantum state
Bipartite quantum states are classified into three categories: separable
states, bound entangled states, and free entangled states. It is of great
importance to characterize these families of states for the development of
quantum information science. In this paper, I show that the separable states
and the bound entangled states have a common spectral property. More precisely,
I prove that for undistillable -- separable and bound entangled -- states, the
eigenvalue vector of the global system is majorized by that of the local
system. This result constitutes a new sufficient condition for distillability
of bipartite quantum states. This is achieved by proving that if a bipartite
quantum state satisfies the reduction criterion for distillability, then it
satisfies the majorization criterion for separability.Comment: 4 pages, no figures, REVTEX. A new lemma (Lemma 2) added. To appear
in Physical Review Letter
Subsurface processes generated by bore-driven swash on coarse-grained beaches
Peer reviewedPublisher PD
Single-stage experimental evaluation of boundary layer bleed techniques for high lift stator blades. Part 4 - Data and performance of triple-slotted 0.75 hub diffusion factor stator
Performance tests on slotted hub diffusion factor stator with boundary layer blee
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