3,005 research outputs found

    Length-Length and Length-Weight Relationships in Nephrops norvegicus from the Aegean Sea (Linnaeus, 1758)

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    The objective of this study was to determine the length-length, length-width and length-weight relationships inNephrops norvegicus as a basis for conversions. A total of 659 specimens were collected with trawl gears from the commercial trawler “Hapuloğlu” between 17 and 21 August 2008 in international waters of the middle Aegean Sea. Morphometric equations for the conversions of length and weight were constructed for females, males, and combined sexes. Females were generally smaller than males, and size-frequency distributions total length (TL), carapace length (CL), and body width (BW) revealed significant differences between females and male

    Analytical solutions of the Klein-Fock-Gordon equation with the Manning-Rosen potential plus a Ring-Shaped like potential

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    In this work, on the condition that scalar potential is equal to vector potential, the bound state solutions of the Klein-Fock-Gordon equation of the Manning-Rosen plus ring-shaped like potential are obtained by Nikiforov-Uvarov method. The energy levels are worked out and the corresponding normalized eigenfunctions are obtained in terms of orthogonal polynomials for arbitrary ll states. The conclusion also contain central Manning-Rosen, central and non-central Hulth\'en potential.Comment: 14 pages. arXiv admin note: substantial text overlap with arXiv:1210.537

    The effect of melatonin on bacterial translocation following ischemia/reperfusion injury in a rat model of superior mesenteric artery occlusion

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    Background: Acute mesenteric ischemia is a life-threatening vascular emergency resulting in tissue destruction due to ischemia-reperfusion injury. Melatonin, the primary hormone of the pineal gland, is a powerful scavenger of reactive oxygen species (ROS), including the hydroxyl and peroxyl radicals, as well as singlet oxygen, and nitric oxide. In this study, we aimed to investigate whether melatonin prevents harmful effects of superior mesenteric ischemia-reperfusion on intestinal tissues in rats. Methods: Rats were randomly divided into three groups, each having 10 animals. In group I, the superior mesenteric artery (SMA) was isolated but not occluded. In group II and group III, the SMA was occluded immediately distal to the aorta for 60 minutes. After that, the clamp was removed and the reperfusion period began. In group III, 30 minutes before the start of reperfusion, 10 mg/kg melatonin was administered intraperitonally. All animals were sacrified 24 hours after reperfusion. Tissue samples were collected to evaluate the I/R-induced intestinal injury and bacterial translocation (BT). Results: There was a statistically significant increase in myeloperoxidase activity, malondialdehyde levels and in the incidence of bacterial translocation in group II, along with a decrease in glutathione levels. These investigated parameters were found to be normalized in melatonin treated animals (group III). Conclusion: We conclude that melatonin prevents bacterial translocation while precluding the harmful effects of ischemia/reperfusion injury on intestinal tissues in a rat model of superior mesenteric artery occlusion. © 2015 Ozban et al.; licensee BioMed Central

    A comparison of the Bering Sea, Gulf of Alaska, and Aleutian Islands large marine ecosystems through food web modeling / by K. Aydin ... [et al.]

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    Detailed mass balance food web models were constructed to compare ecosystem characteristics for three Alaska regions: the eastern Bering Sea (EBS), the Gulf of Alaska (GOA), and the Aleutian Islands (AI). This paper documents the methods and data used to construct the models and compares ecosystem structure and indicators across models. The common modeling framework, including biomass pool and fishery definitions, resulted in comparable food webs for the three ecosystems which showed that they all have the same apex predator—the Pacific halibut longline fishery. However, despite the similar methods used to construct the models, the data from each system included in the analysis clearly define differences in food web structure which may be important considerations for fishery management in Alaska ecosystems. The results showed that the EBS ecosystem has a much larger benthic influence in its food web than either the GOA or the AI. Conversely, the AI ecosystem has the strongest pelagic influence in its food web relative to the other two systems. The GOA ecosystem appears balanced between benthic and pelagic pathways, but is notable in having a smaller fisheries catch relative to the other two systems, and a high biomass of fish predators above trophic level (TL) 4, arrowtooth flounder and halibut. The patterns visible in aggregated food webs were confirmed in additional more detailed analyses of biomass and consumption in each ecosystem, using both the single species and whole ecosystem indicators developed here

    The effects of jig color and lunar bright on coastal squid jigging

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    Squid jigging experiments were carried out to determine whether differences occurred between different colors and lunar brightness in Middle Eastern coast of Aegean Sea. Five different colors of jigs (red, blue, green, orange and white) were used together in same angle. According to one-way analysis of variance results, red jigs were found to be the most efficient in squid  capturing (p < 0.01). General linear model results proved that lunar  brightness of full moon phase showed positive effects to squid catching (p < 0.01). The differences between jigs were statistically significant except  between blue and green. In addition, the relationship between dorsal mantle length of captured specimens and color of jigs were not significant.Key words: Loligo vulgaris, Aegean sea, squid, jigging, colors, lunar phase

    Subwavelength resolution with a negative-index metamaterial superlens

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    Cataloged from PDF version of article.Negative-index metamaterials are candidates for imaging objects with sizes smaller than a half-wavelength. The authors report an impedance-matched, low loss negative-index metamaterial superlens that is capable of resolving subwavelength features of a point source with a 0.13 lambda resolution, which is the highest resolution achieved by a negative-index metamaterial. By separating two point sources with a distance of lambda/8, they were able to detect two distinct peaks on the image plane. They also showed that the metamaterial based structure has a flat lens behavior. (c) 2007 American Institute of Physics

    Using guarding net to reduce regularly discarded invertebrates in trammel net fisheries operating on seagrass meadows (Posidonia oceanica) in Izmir Bay (Eastern Aegean Sea)

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    Prohibition of both beach and boat seines and trawl fishery along the İzmir Bay coasts in the Aegean Sea signifies intensive usage of gillnets and trammel nets, for catching red mullet (Mullus spp.) species in particular. Trials were realized between March 2009 and February 2010 with trammel nets in the areas on the boundaries of the sea grass (Posidonia oceanica) meadows in the Bay. Guarding net (selvedge) was attached to the lead line of experimental nets (Exp1-Exp2) - 36 and 40 mm inner panel. Differences for discard amounts between control group nets (C1-C2) (having the same inner panel as the experimental nets), used by commercial fishermen, and experimental nets are 54.7% for C1-Exp1 and 62.8% for C2-Exp2 (p<0.05). Use of nets with selvedge not only reduced regularly discarded invertebrates (Hexaplex trunculus, Bolinus brandaris, Maja spp.) in the region, but also avoided net damage caused by these species

    Failure of the Standard Coupled-Channels Method in Describing the Inelastic Reaction Data: On the Use of a New Shape for the Coupling Potential

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    We present the failure of the standard coupled-channels method in explaining the inelastic scattering together with other observables such as elastic scattering, excitation function and fusion data. We use both microscopic double-folding and phenomenological deep potentials with shallow imaginary components. We argue that the solution of the problems for the inelastic scattering data is not related to the central nuclear potential, but to the coupling potential between excited states. We present that these problems can be addressed in a systematic way by using a different shape for the coupling potential instead of the usual one based on Taylor expansion.Comment: 10 pages, 4 figures, 1 table, Latex:RevTex4 published in J. Phys. G: Nucl. Part. Phy
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