An automatic opening-closing device for large plankton nets and mid-water trawls

1963 ◽  
Vol 43 (2) ◽  
pp. 295-308 ◽  
Author(s):  
P. Foxton
Keyword(s):  
Depth Distribution ◽  
Size Range ◽  
Geographic Range ◽  
Sufficient Accuracy ◽  
Major Advance ◽  
Monitoring Equipment ◽  
Precise Data ◽  
Plankton Distribution ◽  
Conical Nets ◽  
Reliable Methods

One of the most fundamental problems of oceanic ecology is the study of spatial and temporal changes in plankton distribution and the elucidation of the factors that govern them. A prerequisite of such work is that the tech- niques of sampling should be of sufficient accuracy to allow real changes in distribution to be detected and expressed in quantitative terms. The difficul- ties of fulfilling these sampling requirements are formidable even for the smaller plankton organisms, but a number of reliable and accurate quantitative samplers do exist for animals in this size range. For the larger zooplankton and smaller nekton, however, the lack of suitable sampling gear and methods has to a great extent restricted our knowledge. While the use of large conical nets and trawls at all depths over a wide geographic range has produced a vast body of data on the systematics of the major groups of macroplankton, there is little precise data on the depth distribution of even the commonest forms and only the vaguest estimates are available as to their relative abundance. The lack of more precise data can be attributed to two major technical deficiencies, first, the absence of efficient and reliable methods by which large nets can be opened and closed at depth, and secondly, the lack of accurate depth monitoring equipment. This paper describes the preliminary results of work aimed at meeting the first of these requirements but reference will also be made to the use of an instrument that represents a major advance towards serving the second.

Ontogeny of behaviour relevant to dispersal and connectivity in the larvae of two non-reef demersal, tropical fish species

2009 ◽  
Vol 60 (3) ◽  
pp. 211 ◽  
Author(s):  
Jeffrey M. Leis ◽  
Richard F. Piola ◽  
Amanda C. Hay ◽  
Colin Wen ◽  
Kun-Ping Kan
Keyword(s):  
Depth Distribution ◽  
Size Range ◽  
Reef Fishes ◽  
Population Connectivity ◽  
Marine Fishes ◽  
Tropical Fish ◽  
Larval Behaviour ◽  
Pelagic Larvae ◽  
Geographical Scale

In demersal marine fishes, the dispersal of larvae determines the geographical scale of population connectivity, and larval behaviour may influence dispersal. Yet, little is known of the ontogeny of behaviours that can influence dispersal. The present study examined the development of these behaviours in pelagic larvae of tropical marine fishes (4–21 mm) that occupy non-reef habitats as adults: Eleutheronema tetradactylum (Polynemidae) and Leiognathus equulus (Leiognathidae). In the laboratory, critical speed (Ucrit) increased from 3 to 34 cm s–1 at 1.3–1.7 cm s–1 per mm of size, with the fastest larvae up to 50% faster. In situ speed increased from 4 to 25 cm s–1 at 0.7–2.2 cm s–1 per mm, and was 10–14 body length s–1 (60–90% of Ucrit). Endurance increased from 0 to >40 km at 2.4–4.7 km per mm. In the sea, orientation precision did not change ontogenetically, both species tended to swim in loops, and neither significant overall directionality nor ontogenetic change in orientation was present. Larval orientation of these non-reef species was less precise than that of reef fishes. The two species differed in depth distribution, and one ascended ontogenetically. These behaviours can potentially influence dispersal outcomes over the full size range of these larvae.

A New Ronquil, Bathymaster leurolepis, from the Aleutian Islands

1965 ◽  
Vol 22 (5) ◽  
pp. 1293-1297 ◽  
Author(s):  
J. D. McPhail
Keyword(s):  
New Species ◽  
Depth Distribution ◽  
Gulf Of Alaska ◽  
Geographic Range ◽  
Aleutian Islands ◽  
The Family ◽  
Northern Japan

A new fish of the family Bathymasteridae, Bathymaster leurolepis, is described from the Aleutian Islands. The new species is closely related to B. caeruleofasciatus, with which it has been confused. Bathymaster leurolepis and B. caeruleofasciatus broadly overlap in geographic range, but apparently differ in depth distribution. The geographic range of B. leurolepis is from northern Japan to the Gulf of Alaska.

scholarly journals Changes in distribution of Greenland halibut in a varying environment

2012 ◽  
Vol 70 (2) ◽  
pp. 352-361 ◽  
Author(s):  
M. J. Morgan ◽  
D. Garabana ◽  
R. M. Rideout ◽  
E. Román ◽  
A. Pérez-Rodríguez ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Depth Distribution ◽  
Geographic Range ◽  
Greenland Halibut ◽  
Age Composition ◽  
Intrapopulation Variation ◽  
Deep Waters ◽  
Wide Range ◽  
Varying Environment ◽  
Reduced Temperature

Abstract Morgan, M. J., Garabana, D., Rideout, R. M., Román, E., Pérez-Rodriguez, A. and Saborido-Rey, F. 2013. Changes in distribution of Greenland halibut in a varying environment. – ICES Journal of Marine Science, 70: 352–361. Fish are expected to respond to changing oceanographic temperature by altering their distribution. Off the coast of Newfoundland, Canada, there have been major changes in oceanographic temperature over the last several decades, with both record cold and record warm years being observed. Greenland halibut is an important flatfish species in the area, and is distributed in deep waters over a very wide geographic range. Thus, it might be buffered from temperature change in the overall area by reduced temperature variation at depth, and the diverse temperature conditions over its wide range. We examined intrapopulation variation in temperature and depth distribution, and the biological changes in relation to changes in available temperature. On the Flemish Cap, variation in available temperature was limited, and changes in depth were related to changing age composition and the differential depth distribution with age/size. In other areas there was a larger decline in available temperature, and associated with this, Greenland halibut moved to deeper waters and occupied warmer temperatures than they had previously. Concurrently, growth declined and condition increased. This study shows that shifts in distribution may not result in maintenance of homogeneous environmental conditions, and that resulting biological changes will be difficult to predict.

Northernmost record of the rare brachyuran crab, Paragalene longicrura (Nardo, 1868) (Decapoda, Progeryonidae) from the Istrian Peninsula (Adriatic Sea, Croatia)

Crustaceana ◽  
2020 ◽  
Vol 93 (2) ◽  
pp. 131-156
Author(s):  
Neven Iveša ◽  
Tibor Béres ◽  
Júlia K. Török
Keyword(s):  
Vertical Distribution ◽  
Depth Distribution ◽  
Adriatic Sea ◽  
Size Range ◽  
Habitat Type ◽  
Northern Adriatic Sea ◽  
Brachyuran Crab ◽  
Northern Adriatic ◽  
First Time ◽  
Determining Factor

Abstract Between 2014 and 2019, four specimens of Paragalene longicrura (Nardo, 1868) were accidentally caught in the Adriatic Sea near Pula (Istrian Peninsula, Croatia). These are the first records of the little known species from the northern Adriatic Sea, as well as the northernmost occurrence over its global distribution. We have collected all documented occurrences from the literature since the description of the crab, resulting in a total number of 85 known specimens. Upon comparing the habitat type and depth distribution of our specimens with the recorded sightings, water temperature, and not depth, appeared to be the major determining factor for vertical distribution. Twenty-nine specimens have been detected in museum inventories, but not included in published articles. Our discoveries increased the number of known Adriatic specimens from 7 to 11. For the first time, we compiled all available carapace measurements to get an impression of the size range of the species.

A new 1.4 nm gold-Fab probe

1991 ◽  
Vol 49 ◽  
pp. 284-285
Author(s):  
James F. Hainfeld ◽  
Frederic R. Fumya ◽  
Richard D. Powell
Keyword(s):  
High Resolution ◽  
Gold Particle ◽  
Colloidal Gold ◽  
Size Range ◽  
Life Sciences ◽  
Major Advance ◽  
Trial And Error ◽  
Fab Fragment ◽  
Gold Particles ◽  
Error Testing

A major advance in high resolution EM immunoprobes has recently been achieved: The smallest gold particles easily seen directly in the TEM have been coupled to Fab fragments thus making them the smallest gold-antibody probe commercially available.The gold particle, NanogoldTM, is 1.4 nm in diameter with a very controlled size range, ± 10% (Fig. 1). This is in sharp contrast to other small gold preparations, such as Auroprobe One (Janssen Life Sciences) which actually ranges from 1-3 nm.The Fab conjugate (Fig. 2) has close to one gold particle per Fab fragment. This again is different from other gold-IgG probes that have 0.2-10 gold particles per IgG. Another difference is that the Nanogold-Fab conjugates are separate molecules in solution rather than the often extensive aggregation of other colloidal gold-IgG preparations. The problems of ratio of gold particles to antibody and aggregation in conventional colloidal conjugates were shown to be controllable by careful trial and error testing.

Some Problems in Understanding the Solar Corona

1994 ◽  
Vol 144 ◽  
pp. 1-9
Author(s):  
A. H. Gabriel
Keyword(s):  
Solar Corona ◽  
Solar Atmosphere ◽  
Theoretical Modelling ◽  
Total System ◽  
Major Advance ◽  
X Ray ◽  
Proper Perspective ◽  
Space Observations

The development of the physics of the solar atmosphere during the last 50 years has been greatly influenced by the increasing capability of observations made from space. Access to images and spectra of the hotter plasma in the UV, XUV and X-ray regions provided a major advance over the few coronal forbidden lines seen in the visible and enabled the cooler chromospheric and photospheric plasma to be seen in its proper perspective, as part of a total system. In this way space observations have stimulated new and important advances, not only in space but also in ground-based observations and theoretical modelling, so that today we find a well-balanced harmony between the three techniques.

Microtomy of spherical Al2O3 powders

1983 ◽  
Vol 41 ◽  
pp. 74-75
Author(s):  
E.J. Jenkins ◽  
D.S. Tucker ◽  
J.J. Hren
Keyword(s):  
Thin Film ◽  
Size Range ◽  
Particle Aggregation ◽  
Ion Milling ◽  
Thin Sections ◽  
Α Phase ◽  
Convenient Means ◽  
Van Der Waals Attraction ◽  
Negative Feature ◽  
Film Substrate

The size range of mineral and ceramic particles of one to a few microns is awkward to prepare for examination by TEM. Electrons can be transmitted through smaller particles directly and larger particles can be thinned by crushing and dispersion onto a substrate or by embedding in a film followed by ion milling. Attempts at dispersion onto a thin film substrate often result in particle aggregation by van der Waals attraction. In the present work we studied 1-10 μm diameter Al2O3 spheres which were transformed from the amprphous state to the stable α phase.After the appropriate heat treatment, the spherical powders were embedded in as high a density as practicable in a hard EPON, and then microtomed into thin sections. There are several advantages to this method. Obviously, this is a rapid and convenient means to study the microstructure of serial slices. EDS, ELS, and diffraction studies are also considerably more informative. Furthermore, confidence in sampling reliability is considerably enhanced. The major negative feature is some distortion of the microstructure inherent to the microtoming operation; however, this appears to have been surprisingly small. The details of the method and some typical results follow.

Microdiffraction Patterns of Small Metallic Particles II; Theoretical Analysis

1982 ◽  
Vol 40 ◽  
pp. 668-669
Author(s):  
A. Gómez ◽  
P. Schabes-Retchkiman ◽  
M. José-Yacamán ◽  
T. Ocaña
Keyword(s):  
Experimental Data ◽  
Electron Diffraction ◽  
Theoretical Analysis ◽  
Size Range ◽  
Dynamical Theory ◽  
Metallic Particles ◽  
Splitting Effect

The splitting effect that is observed in microdiffraction pat-terns of small metallic particles in the size range 50-500 Å can be understood using the dynamical theory of electron diffraction for the case of a crystal containing a finite wedge. For the experimental data we refer to part I of this work in these proceedings.

Electron Microscopy of the Shape of Small Metal Particles

1977 ◽  
Vol 35 ◽  
pp. 300-301
Author(s):  
M. Jose Yacaman
Keyword(s):  
Electron Microscopy ◽  
Metal Particle ◽  
Field Experiments ◽  
Size Range ◽  
Dark Field ◽  
Metal Particles ◽  
Bragg Condition ◽  
Crystal Particle ◽  
Small Metal Particle ◽  
Small Metal Particles

In the Study of small metal particles the shape is a very Important parameter. Using electron microscopy Ino and Owaga(l) have studied the shape of twinned particles of gold. In that work electron diffraction and contrast (dark field) experiments were used to produce models of a crystal particle. In this work we report a method which can give direct information about the shape of an small metal particle in the amstrong- size range with high resolution. The diffraction pattern of a sample containing small metal particles contains in general several systematic and non- systematic reflections and a two-beam condition can not be used in practice. However a N-beam condition produces a reduced extinction distance. On the other hand if a beam is out of the bragg condition the effective extinction distance is even more reduced.

Applications of SIMS to electronic materials and devices

1992 ◽  
Vol 50 (2) ◽  
pp. 1682-1683
Author(s):  
S.F. Corcoran
Keyword(s):  
Depth Distribution ◽  
Secondary Ion Mass Spectrometry ◽  
Semiconductor Device ◽  
Electronic Materials ◽  
Profile Analysis ◽  
Semiconductor Industry ◽  
Small Diameter ◽  
Depth Resolution ◽  
Detection Sensitivity

Over the past decade secondary ion mass spectrometry (SIMS) has played an increasingly important role in the characterization of electronic materials and devices. The ability of SIMS to provide part per million detection sensitivity for most elements while maintaining excellent depth resolution has made this technique indispensable in the semiconductor industry. Today SIMS is used extensively in the characterization of dopant profiles, thin film analysis, and trace analysis in bulk materials. The SIMS technique also lends itself to 2-D and 3-D imaging via either the use of stigmatic ion optics or small diameter primary beams.By far the most common application of SIMS is the determination of the depth distribution of dopants (B, As, P) intentionally introduced into semiconductor materials via ion implantation or epitaxial growth. Such measurements are critical since the dopant concentration and depth distribution can seriously affect the performance of a semiconductor device. In a typical depth profile analysis, keV ion sputtering is used to remove successive layers the sample.

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