Larval and early post-larval development of the protobranch bivalve Solemya velum (Mollusca: Bivalvia)

1992 ◽  
Vol 72 (2) ◽  
pp. 383-402 ◽  
Author(s):  
R.G. Gustafson ◽  
R.A. Lutz
Keyword(s):  
Shell Morphology ◽  
Marine Bivalve ◽  
North West ◽  
Larval Stages ◽  
Egg Capsules ◽  
The North ◽  
New Information ◽  
Solemya Velum ◽  
Ciliary Tuft ◽  
Egg Capsule

Early development in the north-west Atlantic awning clam, Solemya velum (Solemyoida: Solemyidae) was examined by light and scanning electron microscopy. Embryonic and pericalymma larval stages, typical of protobranch bivalves, developed within individual adhesive gelatinous egg capsules and offspring emerged at hatching as benthic crawl-away juveniles. Fertilized eggs were light orange in colour, spherical, and had a yolk-mass diameter of approximately 190 μm. Entirely ciliated cylindrical pericalymma larvae, with a length and width of 318 μm and 208 μn, respectively, were obtained within 24 h. These larvae lacked an apical ciliary tuft, possessed nine rows of calymma cells, and actively rotated within the egg capsule. During metamorphosis, which occurred within 48 h of fertilization, the transitory larval ectoderm was entirely ingested. The prodissoconch measured roughly 320 μm in length by 215 μm in height. The foot and ciliated gill buds were well developed by four days after fertilization and subsequent growth contributed to the dissoconch or adult shell. Hatching began at 13 d after fertilization when the shell measured approximately 402 μm in length by 251 μm in height. Actively crawling and burrowing juveniles were cultured for six months after fertilization and an ontogenetic sequence of encapsulated and juvenile shell morphology was obtained for identification purposes. Current contradictory hypotheses regarding the phylogeny of marine bivalve develop-mental types are reviewed in light of new information on the Order Solemyoida.

Feeding ecology of Cuvier's beaked whale (Ziphius cavirostris): a review with new information on the diet of this species

2001 ◽  
Vol 81 (4) ◽  
pp. 687-694 ◽  
Author(s):  
M.B. Santos ◽  
G.J. Pierce ◽  
J. Herman ◽  
A. López ◽  
A. Guerra ◽  
...  
Keyword(s):  
Stomach Contents ◽  
Sperm Whales ◽  
Important Species ◽  
North West ◽  
North East ◽  
The North ◽  
New Information ◽  
Beaked Whales ◽  
Ziphius Cavirostris ◽  
Cuvier’S Beaked Whale

Published information on the diet of Cuvier's beaked whales Ziphius cavirostris (Odontoceti: Ziphiidae) is reviewed and new information on the stomach contents of three animals: two stranded in Galicia (north-west Spain) in February 1990 at A Lanzada, and in February 1995 at Portonovo; and the third stranded in February 1999 in North Uist (Scotland), is presented. The whale stranded in 1990 was a male; the other two were adult females. All animals were >5 m long.  The limited published information on the diet of this species indicates that it feeds primarily on oceanic cephalopods although some authors also found remains of oceanic fish and crustaceans.  Food remains from the three new samples consisted entirely of cephalopod beaks. The Scottish sample set is the largest recorded to date for this species. The prey identified consisted of oceanic cephalopods, mainly squid (Cephalopoda: Teuthoidea). The most frequently occurring species were the squid Teuthowenia megalops, Mastigoteuthis schmidti and Taoniuspavo (for the Galician whale stranded in 1990), Teuthowenia megalops and Histioteuthis reversa (for the second Galician whale) and T. megalops, Gonatus sp. and Taoniuspavo (for the Scottish whale). Other prey included the squid Histioteuthis bonnellii, Histioteuthis arcturi and Todarodes sagittatus as well as Vampiroteuthis infernalis (Cephalopoda: Vampyromorpha), Stauroteuthis syrtensis and Japetella diaphana (Cephalopoda: Octopoda). The squid eaten (estimated from the measurement of the lower beaks) included juvenile and mature individuals of the most important species (Teuthowenia megalops, Gonatus sp.).  The range of species found in the diet of Z. cavirostris is greater than that reported for sperm whales and bottlenosed whales in the north-east Atlantic.

The Captor of Decebalus A New Inscription from Philippi

1970 ◽  
Vol 60 (1) ◽  
pp. 142-153
Author(s):  
Michael Speidel
Keyword(s):  
Roman Army ◽  
North West ◽  
The North ◽  
New Information ◽  
First Time

A huge tombstone with two reliefs and a Latin inscription accidentally came to light in 1965 in the fields of Grammeni, a village to the north-west of the ancient Philippi in Macedonia (Pl. XIII). The inscription represents the most detailed career of a Roman soldier so far known, providing new information on the structure and functioning of the Roman army. Its hero is revealed as the ‘captor’ of King Decebalus, one of imperial Rome's greatest antagonists, and his spectacular deed is portrayed on one of the two reliefs. The new find deserves special attention and is published here for the first time.

Changes in Pipeline Embedment due to Sediment Mobility: Observations and Implications for Design

2013 ◽  
Author(s):  
Antonio Borges Rodriguez ◽  
M. Fraser Bransby ◽  
Ian M. S. Finnie ◽  
Han Eng Low ◽  
David J. White
Keyword(s):  
Detailed Examination ◽  
Temporal Variations ◽  
Data Set ◽  
Offshore Pipelines ◽  
North West ◽  
The North ◽  
New Information ◽  
Calculation Methodology ◽  
Industry Practice ◽  
Sediment Mobility

This paper describes temporal variations in embedment of several existing pipelines on the North-West Shelf (NWS) of Australia, and the sediment mobility processes that cause them. Distinct and explainable patterns in the extent, distribution and rate of the development of pipeline embedment have been revealed through systematic detailed examination of repeated annual integrity surveys by ROV. This represents a unique data-set that has been used to optimize the reliability of a newly designed pipeline. This paper explains why these clear findings should not be overlooked in both the buckling and stability design of initially unburied pipelines, which is in contrast to currently established industry practice. This new information supports the presumption that conventional approaches for calculating the hydrodynamic stability of unburied pipelines may be more conservative than necessary. Conversely, and arguably more importantly, it is shown that conventionally accepted methods for calculating pipe-seabed resistance forces when planning buckling schemes should be considered unsafe if embedment due to sediment mobility is possible. Consequently, this paper proposes an innovative calculation methodology that statistically captures these sediment mobility effects, and which facilitates a more justifiable geotechnical input to pipeline engineering than what is conventionally adopted. This methodology is currently being used by the authors as a state-of-the-art design practice for unburied offshore pipelines in regions of sediment mobility.

SEM and TEM observations of sperm development in the testis of the freshwater fish Oreochromis mossambicus

1990 ◽  
Vol 48 (3) ◽  
pp. 58-59
Author(s):  
Daryl A. Cornish ◽  
George L. Smit
Keyword(s):  
Morphological Characteristics ◽  
Oreochromis Mossambicus ◽  
Breeding Cycle ◽  
Limited Information ◽  
North West ◽  
The North ◽  
Sem And Tem ◽  
Sperm Development ◽  
Ultrastructural Characteristics ◽  
The University

Oreochromis mossambicus is currently receiving much attention as a candidater species for aquaculture programs within Southern Africa. This has stimulated interest in its breeding cycle as well as the morphological characteristics of the gonads. Limited information is available on SEM and TEM observations of the male gonads. It is known that the testis of O. mossambicus is a paired, intra-abdominal structure of the lobular type, although further details of its characteristics are not known. Current investigations have shown that spermatids reach full maturity some two months after the female becomes gravid. Throughout the year, the testes contain spermatids at various stages of development although spermiogenesis appears to be maximal during November when spawning occurs. This paper describes the morphological and ultrastructural characteristics of the testes and spermatids.Specimens of this fish were collected at Syferkuil Dam, 8 km north- west of the University of the North over a twelve month period, sacrificed and the testes excised.

The North West Passage

2014 ◽  
Author(s):  
Roald Amundsen ◽  
Godfred Hansen
Keyword(s):  
North West ◽  
The North

Russian Oil: Production and Exports

2003 ◽  
pp. 136-146
Author(s):  
K. Liuhto
Keyword(s):  
Baltic Sea ◽  
Statistical Data ◽  
Oil Production ◽  
The Baltic Sea ◽  
North West ◽  
The North ◽  
Oil Transportation ◽  
Sea Ports ◽  
The Baltic

Statistical data on reserves, production and exports of Russian oil are provided in the article. The author pays special attention to the expansion of opportunities of sea oil transportation by construction of new oil terminals in the North-West of the country and first of all the largest terminal in Murmansk. In his opinion, one of the main problems in this sphere is prevention of ecological accidents in the process of oil transportation through the Baltic sea ports.

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