19,201 research outputs found

    Configurational Temperature in Membrane Simulations Using Dissipative Particle Dynamics

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    The use of excessively long timesteps in dissipative particle dynamics simulations may produce simulation artifacts due to the generation of configurations which are not representative of the desired canonical ensemble. The configurational temperature, amongst other quantities, may be used to assess the extent of the deviation from equilibrium. This paper presents results for simulations of models of water, and lipid bilayer membranes, to illustrate the nature of the problems.Comment: 13 pages, 7 figures, RevTex

    Realizing the Potential of Marine Biotechnology : Challenges and Opportunities

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    A paid open access option is available for this journal. Author's final version or publisher's version/PDF Authors may deposit in funding agency designated repository after 12 monthsPeer reviewedPublisher PD

    A note on muscle composition and colour of Holstein-Friesian, Piedmontese × Holstein-Friesian and Romagnola × Holstein-Friesian steers.

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    peer-reviewedHolstein-Friesian (HF), Piedmontese × Holstein-Friesian (PM) and Romagnola × Holstein-Friesian (RO) steers were compared for muscle composition and colour. A total of 120 steers in a 3 breed types (HF, PM and RO) × 2 feeding levels (low and high) × 2 finishing periods (short, S and extended, E) factorial experiment were used. Three samples of m. longissimus were taken for chemical analysis, measurement of drip loss and Hunterlab colour measurements. Muscle moisture and protein concentrations were lower, and lipid concentration was higher for HF than for PM and RO, which were similar. There were no effects of feeding level on chemical composition, but after blooming all colour values except hue were lower for the higher feeding level. The E finishing period reduced moisture, protein, drip-loss, L (lightness), a (redness) and chroma values. It is concluded that PM and RO had similar muscle composition but HF had a higher lipid concentration. Feeding level had few effects on muscle composition, but extended finishing increased all measures of fatness and reduced colour values

    Characterising submonolayer deposition via visibility graphs

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    We use visibility graphs as a tool to analyse the results of kinetic Monte Carlo (kMC) simulations of submonolayer deposition in a one-dimensional point island model. We introduce an efficient algorithm for the computation of the visibility graph resulting from a kMC simulation and show that from the properties of the visibility graph one can determine the critical island size, thus demonstrating that the visibility graph approach, which implicitly combines size and spatial data, can provide insights into island nucleation and growth processes

    Ecology of fishes in Upper Newport Bay, California: seasonal dynamics and community structure

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    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.

    Clinical features of pneumonia in extreme old age

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    The clinical features of 70 people over the age of 85 with radiologically positive pneumonia were studied. It was shown that the classical presenting symptoms of pneumonia were often absent and 81 % had one or more acute ’geriatric’ features such as acute confusion, recent onset of falls, recent worsening immobility or recent onset of incontinence, at the time of presentation. An increased risk of mortality was associated with acute confusion, dementia, central cyanosis and long term immobility. Well kept body temperature and respiratory rate charts provide a useful early warning of possible pneumonia in very elderly in patients and the finding of a raised body temperature with a raised respiratory rate should always prompt the need to rule out lower respiratory tract infection.peer-reviewe

    Maximally Symmetric Spin-Two Bitensors on S3S^3 and H3H^3

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    The transverse traceless spin-two tensor harmonics on S3S^3 and H3H^3 may be denoted by T(kl)abT^{(kl)}{}_{ab}. The index kk labels the (degenerate) eigenvalues of the Laplacian □\square and ll the other indices. We compute the bitensor ∑lT(kl)ab(x)T(kl)a′b′(x′)∗\sum_l T^{(kl)}{}_{ab}(x) T^{(kl)}{}_{a'b'}(x')^* where x,x′x,x' are distinct points on a sphere or hyperboloid of unit radius. These quantities may be used to find the correlation function of a stochastic background of gravitational waves in spatially open or closed Friedman-Robertson-Walker cosmologies.Comment: 12 pages, RevTeX, uuencoded compressed .tex file, minor typos correcte
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