SciCombinator

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Concept: Torpedo

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The submarine H.L. Hunley was the first submarine to sink an enemy ship during combat; however, the cause of its sinking has been a mystery for over 150 years. The Hunley set off a 61.2 kg (135 lb) black powder torpedo at a distance less than 5 m (16 ft) off its bow. Scaled experiments were performed that measured black powder and shock tube explosions underwater and propagation of blasts through a model ship hull. This propagation data was used in combination with archival experimental data to evaluate the risk to the crew from their own torpedo. The blast produced likely caused flexion of the ship hull to transmit the blast wave; the secondary wave transmitted inside the crew compartment was of sufficient magnitude that the calculated chances of survival were less than 16% for each crew member. The submarine drifted to its resting place after the crew died of air blast trauma within the hull.

Concepts: Causality, Shock wave, American films, Submarine, Ship, BLAST, Torpedo, Bow

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Norway has monitored the marine environment around the sunken Russian nuclear submarine Komsomolets since 1990. This study presents an overview of 25 years of Norwegian monitoring data (1990-2015). Komsomolets sank in 1989 at a depth of 1680 m in the Norwegian Sea while carrying two nuclear torpedoes in its armament. Subsequent Soviet and Russian expeditions to Komsomolets have shown that releases from the reactor have occurred and that the submarine has suffered considerable damage to its hulls. Norwegian monitoring detected 134Cs in surface sediments around Komsomolets in 1993 and 1994 and elevated activity concentrations of 137Cs in bottom seawater between 1991 and 1993. Since then and up to 2015, no increased activity concentrations of radionuclides above values typical for the Norwegian Sea have been observed in any environmental sample collected by Norwegian monitoring. In 2013 and 2015, Norwegian monitoring was carried out using an acoustic transponder on the sampling gear that allowed samples to be collected at precise locations, ∼20 m from the hull of Komsomolets. The observed 238Pu/239,240Pu activity ratios and 240Pu/239Pu atom ratios in surface sediments sampled close to Komsomolets in 2013 did not indicate any releases of Pu isotopes from reactor or the torpedo warheads. Rather, these values probably reflect the overprinting of global fallout ratios with fluxes of these Pu isotopes from long-range transport of authorised discharges from nuclear reprocessing facilities in Northern Europe. However, due to the depth at which Komsomolets lies, the collection of seawater and sediment samples in the immediate area around the submarine using traditional sampling techniques from surface vessels is not possible, even with the use of acoustic transponders. Further monitoring is required in order to have a clear understanding of the current status of Komsomolets as a potential source of radioactive contamination to the Norwegian marine environment. Such monitoring should involve the use of ROVs or submersibles in order to obtain samples next to and within the different compartments of the submarine.

Concepts: Norway, Nuclear weapon, Russia, Radioactive contamination, Radionuclide, Nuclear reprocessing, Submarine, Torpedo

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The electric organ of Tetronarce californica (an electric ray formerly known as Torpedo californica) is a classic preparation for biochemical studies of cholinergic neurotransmission. To broaden the usefulness of this preparation, we have performed a transcriptome assembly of the presynaptic component of the electric organ (the electric lobe). We combined our assembled transcriptome with a previous transcriptome of the postsynaptic electric organ, to define a MetaProteome containing pre- and post-synaptic components of the electric organ.

Concepts: Chemical synapse, Torpedo

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Early onset and late onset essential tremor (ET) cases differ in several respects. Whether they differ with respect to cerebellar pathologic changes remains to be determined. We quantified a broad range of postmortem features (Purkinje cell (PC) counts, PC axonal torpedoes and associated axonal changes, heterotopic PCs, and hairy basket ratings) in 30 ET cases with age of tremor onset <50 years, 30 ET cases with age of tremor onset ≥50 years, and 30 controls (total n = 90). We also used two alternative age of onset cut-points (<40 vs. ≥40 years, and <60 vs. ≥60 years) to define early onset vs. late onset ET. We found that ET cases with tremor onset <50 years and tremor onset ≥50 years had similar PC counts (8.78 ± 1.70 vs. 8.86 ± 1.24, p = 0.839), PC axonal torpedo counts (17.87 ± 18.27 [median =13.00] vs. 12.90 ± 10.60 [median =9.0], p = 0.486) and associated axonal pathology (all p values >0.05), heterotopic PC counts (9.90 ± 11.55 [median =6.00] vs. 5.40 ± 5.10 [median =3.50], p = 0.092), and hairy basket ratings (1.95 ± 0.62 [median =2.00] vs. 2.05 ± 0.92 [median =2.00], p = 0.314). When using the age of onset cut-points of 40 or 60 years, results were similar. Early onset and late onset ET cases share similar cerebellar postmortem features. These data do not support the notion that these age-of-onset related forms of ET represent distinct clinical-pathological entities.

Concepts: Neuron, Pathology, The Age, Cerebellum, Purkinje cell, Parallel fiber, Jan Evangelista Purkyně, Torpedo

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The present study provides a parasitological analysis of the elasmobranch species caught in the northern and central Adriatic Sea. A total of 62 marine leeches were recorded on 747 individuals of Raja clavata Linnaeus, 1758 (thornback ray), Myliobatis aquila Linnaeus, 1758 (common eagle ray), and Torpedo marmorata Risso, 1810 (marbled torpedo ray) caught in 56 hauls over a 5 yr period. All leeches were identified as Pontobdella muricata, which is a typical ectoparasite of benthic elasmobranchs. The prevalence of infection ranged from 7.11% in R. clavata to 12.00% in M. aquila. The intensity of infection, the preferential sites of attachment to the host, and the periodicity of infection were evaluated.

Concepts: Batoidea, Elasmobranchii, Torpedo, Raja, Thornback ray, Myliobatiformes

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The role of PACAP in spermatogenesis and steroidogenesis has been largely investigated in last years in mammals; conversely, a few studies have been performed in non mammalian vertebrates. In this paper we investigated the sequence, expression and localization of PACAP and its PAC1 receptor in the testis of the benthic elasmobranch Torpedo marmorata, the marbled electric ray. Cloning a partial PACAP cDNA, we demonstrated for the first time in elasmobranches that PACAP shows a highly conserved sequence, compared with the PACAP of other chordates (tunicates and vertebrates). Moreover, the phylogenetic analysis revealed that PACAP has been well preserved during evolution and that a negative selection acts on PACAP sequence, leading to the conservation of the coding sites. The phylogenetic consensus tree showed also that Torpedo PACAP is more related with amphibian PACAP than with teleost one. Finally, we demonstrated that in Torpedo marmorata PACAP and its PAC1 receptor are synthesized directly in the testis, where they show a wider localization than mammals, suggesting that this neuropeptide is involved in the control of Torpedo spermatogenesis.

Concepts: Molecular biology, Species, Fish, Computational phylogenetics, Chordate, Batoidea, Conserved sequence, Torpedo

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Metal concentrations (Hg, Cd, Pb, As, Cr, Cu, Zn and Ni) were measured in the liver of two fish, Torpedo nobiliana (electric ray) and Torpedo marmorata (marbled electric ray), from the Mediterranean Sea in order to comparatively investigate their current pollution status. Maximum mean levels of Hg were detected in electric ray (mean: 2.16μgg(-1) ww), while marbled electric ray accumulated especially Cd (mean: 0.06μgg(-1) ww), Cu (mean: 3.83μgg(-1) ww) and As (mean: 32.64μgg(-1) ww). The metal concentrations are similar to those reported in literature, except for Cd, As and Ni. Hg concentrations increased with increasing fish body length in both species, whilst no significant concentration-size relationship was found for other metals. To the best of our knowledge this is the first report providing information on trace metal levels and relationship between concentration and size of these cartilaginous fishes. Future studies on the concentrations and effects of environmental contaminants in various torpedinid species are surely needed.

Concepts: Fish, Metal, Copper, Batoidea, Chondrichthyes, Torpedo, Marbled electric ray

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Standardised diets and trophic level (T L) estimates were calculated for 75 ray species from the suborders Myliobatoidei (67 spp.) and Torpedinoidei (8 spp.). Decapod crustaceans (31.71±3.92%) and teleost fishes (16.45±3.43%) made the largest contribution to the standardised diet of the Myliobatoidei. Teleost fishes (37.40±16.09%) and polychaete worms (31.96±14.22%) were the most prominent prey categories in the standardised diet of the suborder Torpedinoidei. Cluster analysis identified nine major trophic guilds the largest of which were decapod crustaceans (24 species), teleost fishes (11 species) and molluscs (11 species). Trophic level estimates for rays ranged from 3.10 for Potamotrygon falkneri to 4.24 for Gymnura australis, Torpedo marmorata and T. nobiliana. Secondary consumers with a T L <4.00 represented 84% of the species examined, with the remaining 12 species (16%) classified as tertiary consumers (T L ≥4.00). Tertiary consumers included electric rays (Torpedo, 3 spp. and Hypnos, 1 sp.), butterfly rays (Gymnura, 4 spp.), stingrays (2 spp.) and Potamotrygonid stingrays (2 spp.). Feeding strategies were identified as the primary factor of influence with respect to Myliobatoidei and Torpedinoidei T L estimates with inter-family comparisons providing the greatest insight into Myliobatoidei and Torpedinoidei relationships.

Concepts: Species, Ecology, Batoidea, Trophic level, Shrimp, Decapoda, Torpedo, Potamotrygonidae

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The pituitary adenylate cyclase-activating polypeptide (PACAP) is a member of the glucagon-related family and occurs in two amidated forms, PACAP38 and PACAP27, with 38 and 27 amino acids, respectively. PACAP acts by binding to three different receptors, that are classified by their binding affinity for PACAP and VIP (vasoactive intestinal polypeptide): PAC(1) R (PACAP-specific receptor) exclusively binds PACAP, while VPAC(1) R (VIP/PACAP receptor, subtype 1) and VPAC(2) R (VIP/PACAP receptor, subtype 2) bind both PACAP and VIP. PACAP, first discovered in the brain, was then localized in several peripheral tissues of mammals, including the ovary. Besides mammals, PACAP and its receptors have been reported in fish too; however, less is known about the presence of PACAP in the fish ovary and the studies are limited to teleosts. The aim of our work was to study the distribution of the PACAP/PACAP-Rs system in the ovary of the cartilaginous fish Torpedo marmorata. Using in situ hybridization (ISH) and immunohistochemistry techniques, we demonstrated that PACAP and its receptors are widely represented in the Torpedo ovary in a stage-dependent manner. Moreover, our findings suggest an involvement of this peptide in the whole follicologenesis, probably influencing steroidogenesis, follicle development, and oocyte growth. J. Exp. Zool. 319A:1-9, 2013. © 2012 Wiley Periodicals, Inc.

Concepts: Protein, Amino acid, Peptide hormone, Great white shark, Batoidea, Shark, Chondrichthyes, Torpedo