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  • 1
    Electronic Resource
    Electronic Resource
    The protein composition of bovine myelin-free axons
    Amsterdam : Elsevier
    BBA - Protein Structure 439 (1976), S. 133-145 
    Details
    ISSN: 0005-2795
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0005-2795(76)90169-0
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  • 2
    Electronic Resource
    Electronic Resource
    Ecological and evolutionary significance of pelagic spermatophores of vermetid gastropods (1980)
    Springer
    Marine biology 57 (1980), S. 315-325 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Sperm are disseminated in vermetid gastropods by spermatophores released freely into the ocean. Spermatophores from 7 species of vermetids, including 3 genera, were obtained from reproductively active males or offshore plankton tows or both. Each vermetid spermatophore consists of a sperm mass containing highly ordered eupyrene and apyrene sperm enveloped concentrically by 3 transparent capsules. Generic and specific differences occur in the size, shape and composition of the sperm mass and capsule. The complexly layered spermatophore is assembled in the male reproductive tract, which includes and elaborate set of pallial reproductive glands for capsule production. Spermatophores are liberated by males into the seawater, and there dispersed by water movements. Some of these drifting spermatophores become entangled in the mucous feeding nets of female vermetids and are then activated by feeding movements. Activation of the complex ejaculatory apparatus appears to result from an interplay of osmotic and mechanical mechanisms. Spermatophores remain viable in the laboratory for 12 to 20 h after release from the male; after 20 h, the sperm mass breaks down and the sperm become immotile. Plankton tows capture some spermatophores with motile sperm and others in which sperm are no longer active. Evolutionary implications of the relationship between production of pelagic spermatophores, sessile mode of life and other aspects of vermetid biology are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00387574
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  • 3
    Electronic Resource
    Electronic Resource
    Catecholamines and dihydroxyphenylalanine in metamorphosing larvae of the nudibranch Phestilla sibogae Bergh (Gastropoda: Opisthobranchia) (1997)
    Springer
    Journal of comparative physiology 181 (1997), S. 187-194 
    Details
    ISSN: 1432-1351
    Keywords: Key words Mollusca ; Opisthobranchia ; High-performance liquid chromatography ; Catecholamines ; Metamorphosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The content of catecholamines and dihydroxyphenylalanine in larvae of the nudibranch Phestilla sibogae was analyzed by high-performance liquid chromatography with electrochemical detection. Dihydroxyphenylalanine, norepinephrine and dopamine were identified in larvae of all ages examined (5 through 12 days post-fertilization). Dihydroxyphenylalanine could be accurately quantified only in larvae of ages 8 through 12 days, when its average concentration increased from 0.62 to 6.71 × 10−2 pmol μg protein−1. Between ages 5 and 12 days dopamine rose from 0.081 to 0.616 pmol μg protein−1, and norepinephrine from 0.45 to 2.17 × 10−2 pmol μg protein−1. Dihydroxyphenylalanine, dopamine and norepinephrine were also measured at different stages of metamorphic progress in 10- to 12-day larvae. Dihydroxyphenylalanine increased by a factor of 2.4 between the onset and completion of metamorphosis, but levels of dopamine and norepinephrine remained stable. One millimolar alpha-methyl-dl-m-tyrosine, an inhibitor of catecholamine synthesis, inhibited natural metamorphosis and depleted endogenous norepinephrine and especially dopamine, respectively, to 75% and 35% of control values. The existence of unexpectedly high levels of catecholamines in metamorphically competent larvae, and the association of catecholamine depletion with inhibition of metamorphosis, indicate that these compounds may participate in the control of gastropod development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003590050105
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  • 4
    Electronic Resource
    Electronic Resource
    The vermetidae (Mollusca: Gastropoda) of the Hawaiian Islands (1972)
    Springer
    Marine biology 12 (1972), S. 81-98 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The Hawaiian vermetid fauna comprises 8 species, 7 of which are here described as new. The generic distribution includes 5 species of Dendropoma and 1 each of Petaloconchus, Vermetus and Serpulorbis. The species descriptions rely little on conchology, stressing instead descriptions of animals, habitats and reproductive and developmental characteristics. Feeding is accomplished in all species by a combination of mucous nets and detrital collection by ctenidial cilia. Only in the single species of Vermetus, an inhabitant of quiet waters, does ciliary feeding predominate. Four small species of Dendropoma inhabit shallow, coralline algal-encrusted, wave-washed reef areas, while Serpulorbis and Dendropoma platypus are found not only in intertidal areas subjected to heavy surf, but subtidally to depths of 10 m or more. The single species of Petaloconchus is a characteristic associate of the 4 Dendropoma spp. of shallow waters but, being strongly associated with the coral Porites, Petaloconchus also extends subtidally. The Hawaiian vermetids are very abundant in some localities, with densities ranging up to 60,000/m3 in one species of Dendropoma. Reproduction is continuous in all Hawaiian vermetids, most of which produce small hatching juveniles rather than swimming veligers. Only Serpulorbis and Vermetus have obligatory planktonic stages. Petaloconchus and Dendropoma species may produce a mixture of hatching juveniles and short-term planktonic veligers. Larval or juvenile size is correlated with available nurse yolk, not with egg size.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00347431
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  • 5
    Electronic Resource
    Electronic Resource
    Waterborne chemical compounds in tropical macroalgae: positive and negative cues for larval settlement (1996)
    Springer
    Marine biology 126 (1996), S. 383-393 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Settlement sites of marine invertebrate larvae are frequently influenced by positive or negative cues, many of which are chemical in nature. Following from the observation that many shallow-water, Hawai'ian marine macroalgae are free of fouling by sessile invertebrates, we predicted that the algae are chemically protected and dependent on either surface-bound or continuously released soluble compounds to deter settling invertebrate larvae. To address the importance of waterborne algal compounds, we experimentally determined whether larvae of two of Hawai'i's dominant hard-surface fouling organisms, the polychaete tube worm Hydroides elegans and the bryozoan Bugula neritina, would settle in the presence of waters conditioned by 12 species of common Hawai'ian macroalgae (representing the Phaeophyta, Chlorophyta, Rhodophyta and Cyanophyta). The results included a full spectrum of biological responses by each larval species to waterborne algal compounds. Larval responses to conditioned water were consistent for each algal species, but the outcomes were not predictable based on the taxonomic relationships of the algae. For example, among the species of Phaeophyta examined, different conditioned waters were: (1) toxic, (2) inhibited settlement, (3) simulated settlement, or (4) had no effect, compared to larvae in control dishes containing filtered seawater. Additionally, larval responses to aged (24 h) conditioned waters could not be predicted from the results of assays run with conditioned waters utilized immediately after preparation. Finally, settlement by larvae of one species did not predict outcomes of tests for the other species. Four of 12 shallow-reef Hawai'ian macroalgae tested released compounds into surrounding waters that immediately killed or inhibited settlement by both H. elegans and B. neritina (toxic: Dictyota sandvicensis; inhibitory: Halimeda discoidea, Sphacelaria tribuloides, Ulva reticulata); the remaining 8 algal species prevented settlement by one of these fouling organisms but for the other had no effect or, in some cases, even stimulated settlement
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00354620
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  • 6
    Electronic Resource
    Electronic Resource
    Role of bacteria in larval settlement and metamorphosis of the polychaete Hydroides elegans (1999)
    Springer
    Marine biology 133 (1999), S. 55-64 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The serpulid polychaete Hydroides elegans Haswell, 1883 is an early colonist of new substrata in Pearl Harbor, Oahu, Hawaii. When metamorphically competent, larvae of H. elegans will settle rapidly upon an acceptably biofilmed surface, but not on a clean surface. In this study we found the ability of larvae to respond selectively to inductive surfaces to be retained for at least 3 wk. Of a series of bacterial strains isolated from Hawaiian marine biofilms, 13 induced larval settlement, 11 gave moderate or mixed results, and 10 others did not stimulate the settlement of H. elegans. The amount of settlement induced by monospecific strains was rarely as great as with natural, multispecies films. Most of the isolated bacteria were motile Gram-negative rods, but Gram-positive strains were also present, and diverse metabolic types were represented in the study. Biofilms killed by treatment with heat, ultraviolet radiation or chemical fixatives were no longer inductive. Soluble, dialyzable, heat-stable bacterial products induced settlement and metamorphosis more slowly. The range of bacteria producing an inductive signal suggests either that there are multiple cues, or that the cue is common to many bacteria. Chemical signals characteristic of early microbial biofilms may indicate freshly available substrata with optimal potential for the growth and survival of H. elegans.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002270050442
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  • 7
    Electronic Resource
    Electronic Resource
    Planctosphaera (Hemichordata: Enteropneusta) in the Pacific Ocean (1983)
    Springer
    Marine biology 73 (1983), S. 151-153 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Four specimens of the unusual hemichordate larva Planctosphaera sp., previously known only from the North Atlantic Ocean were collected by midwater trawl from depths of 75 to 500 m near the Hawaiian Islands in May 1974 and in September 1977 and 1982. The anatomy of the Pacific specimens is indistinguishable from published descriptions of those from the Atlantic. The distribution of known specimens of planctosphaera in subsurface or deeper waters in both major ocean systems of the world suggests that they are larvae of a widely distributed species, perhaps from abyssal depths.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00406882
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  • 8
    Electronic Resource
    Electronic Resource
    Passive scalar diffusion from surface sources in the convective boundary layer (1994)
    Springer
    Boundary layer meteorology 69 (1994), S. 417-448 
    Details
    ISSN: 1573-1472
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract We examine vertical and horizontal diffusion of a passive scalar puff from a surface point source in a convective boundary layer (CBL). Numerical results are presented from a large-eddy simulation (LES) with embedded subgrid Lagrangian particle simulation (LPS). There is good agreement in most respects with previous laboratory and numerical studies. Analytical approximations for the concentration, horizontal flux and vertical flux are found to work reasonably well; they are based on the assumption that the concentration follows a Gaussian function in the horizontal and vertical, and that the dimensionless width and height scales of the puff follow simple functions of time. Fluxes and concentration gradients are related through a continuity relationship, without the need for an eddy diffusivity assumption. The instantaneous, point-source fields can be integrated for any source geometry. We compare predictions from the LES/LPS model for a sinusoidal surface flux with previous results from an LES with sinusoidal buoyancy flux and confirm that the buoyancy perturbations diffuse like a passive scalar. We also consider a continuous point source and derive footprint functions for vertical flux measurements above the surface layer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00718128
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  • 9
    Electronic Resource
    Electronic Resource
    Large-eddy simulations of thermally forced circulations in the convective boundary layer. Part II: The effect of changes in wavelength and wind speed (1992)
    Springer
    Boundary layer meteorology 58 (1992), S. 307-327 
    Details
    ISSN: 1573-1472
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract This paper extends previous large-eddy simulations of the convective boundary layer over a surface with a spatially varying sensible heat flux. The heat flux variations are sinusoidal and one-dimensional. The wavelength is 1500 or 4500 m (corresponding to 1.3 and 3.8 times the boundary-layer depth, respectively) and the wind speed is 0, 1 or 2 m s-1. In every case the heat flux variation drives a mean circulation. As expected, with zero wind there is ascent over the heat flux maxima. The strength of the circulation increases substantially with an increase in the wavelength of the perturbation. A light wind weakens the circulation drastically and moves it downwind. The circulation has a significant effect on the average concentration field from a simulated, elevated source. The heat flux variation modulates turbulence in the boundary layer. Turbulence is stronger (in several senses) above or downwind of the heat flux maxima than it is above or downwind of the heat flux minima. The effect remains significant even when the mean circulation is very weak. There are effects too on profiles of horizontal-average turbulence statistics. In most cases the effects would be undetectable in the atmosphere. We consider how the surface heat flux variations penetrate into the lower and middle boundary layer and propose that to a first approximation the process resembles passive scalar diffusion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00120235
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  • 10
    Electronic Resource
    Electronic Resource
    Large-eddy simulations of thermally forced circulations in the convective boundary layer. Part I: A small-scale circulation with zero wind (1991)
    Springer
    Boundary layer meteorology 57 (1991), S. 79-114 
    Details
    ISSN: 1573-1472
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract We have conducted large-eddy simulations (LES) of the atmospheric boundary layer with surface heat flux variations on a spatial scale comparable to the boundary layer depth. We first ran a simulation with a horizontally homogeneous heat flux. In general the results are similar to those of previous large-eddy simulations. The model simulates a field of convective eddies having approximately the correct velocity and spatial scales, and with the crucial property that kinetic energy is transported vigorously upwards through the middle levels. However, the resolved temperature variance is only about half what is observed in the laboratory or the atmosphere. This deficiency — which is shared by many other large-eddy simulations — has dynamic implications, particularly in the pressure/temperature interaction terms of the heat flux budget. Recent simulations by other workers at much higher resolution than ours appear to be more realistic in this respect. The surface heat flux perturbations were one-dimensional and sinusoidal with a wavelength equal to 1.3 times the boundary-layer depth. The mean wind was zero. Results were averaged over several simulations and over time. There is a mean circulation, with ascent over the heat flux maxima (vertical velocity ~0.1w *) and descent over the heat flux minima. Turbulence is consistently stronger over the heat flux maxima. The horizontal velocity variance components (calculated with respect to the horizontal average) become unequal, implying that convective eddies are elongated parallel to the surface heat flux perturbations. A consideration of the budgets for temperature and velocity suggests several simplifying concepts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00119714
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