48 research outputs found

    Condition and length-weight relationship of the horse mackerel (Trachurus trachurus L.) and the Mediterranean horse mackerel (Trachurus mediterraneus L.) from the eastern Adriatic sea

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    The length-weight relationship and variation of condition factor in relation to the total length (TL) of Trachurus trachurus (Linnaeus, 1758) and Trachurus mediterraneus (Steindachner, 1868) were studied. Samples were collected in the eastern Adriatic Sea using bottom-trawl during 2008 and 2009. The b values for males, females and total sample showed that the growth of T. trachurus was isometric, i.e. equal in length and weight. The growth of the males and females of T. mediterraneus was positively allometric while the total sample (males, female and immature) showed isometric growth. The condition factor was calculated indicating the smallest values in immature specimens. The highest values of condition factor for males and females of both species were observed in the range of TL from 16 to 19 cm and 31 to 33 cm, respectively

    Biometrijske osobine šnjura pučinara, Trachurus mediterraneus, (Osteichthyes: Carangidae) u srednjem Jadranu

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    The relationship between morphometric measurements (15) and meristic characters (8) were examined in 237 specimens of Mediterranean horse mackerel (105 females, 101 males and 31 immature specimens) caught in the central Adriatic Sea. The goal of this paper was to investigate: whether there are morphological differences between males and females; the existence of homogenous or heterogeneous morphology stock; changes in morphometric characters with an increase in body length. Morphological differences between males and females were not marked. Modal values specific for Trachurus species morphologic characters, such as number of lateral line scales, maximum height of scales in anterior and posterior part of lateral line, point at which dorsal accessory lateral line is terminated and values of other biometric properties indicated a possible homogeneous morphology stock of T. mediterraneus in the central Adriatic Sea. Changes in some morphometric characters obtained in conjunction with an increase in body length showed that smaller specimens have longer head, anal and ventral fin than adult specimens. On the other hand, with an increase in total length, the fish have larger preorbital and postorbital distance, smaller eye and maximum height of scales in the lateral line than smaller fishes. The negative correlation recorded for the maximum and minimum body depth indicates that the body becomes progressively elongated. The meristic characters of Mediterranean horse mackerel from different Mediterranean and NE Atlantic areas are mostly in agreement with the data in our study.Na 237 primjeraka šnjura pučinara (105 ženki, 101 mužjak i 31 spolno nezrelih jedinki) ulovljenih u srednjem Jadranu analizirana su morfometrijska (15) i meristička obilježja (8). Cilj ove studije bio je istražiti morfološke razlike između mužjaka i ženki, postojanje morfološki homogenog ili heterogenog stoka i promjene morfometrijskih osobina tijekom rasta ribe. Morfološke razlike između mužjaka i ženki nisu izražene. Modalne vrijednosti specifičnih morfoloških obilježja, kao što su broj ljusaka u bočnoj pruzi, najveća visina ljusaka u prednjem i stražnjem dijelu bočne pruge i točka gdje završava dodatna leđna bočna pruga te vrijednosti ostalih biometrijskih osobina ukazuju da u Jadranu vjerojatno obitava morfološki homogena populacija ove vrste. Uočene su promjene morfometrijskih odnosa u vezi s porastom tjelesne dužine. Manji primjerci imaju veću dužinu glave, podrepnu i trbušne peraje nego veći primjerci. S druge strane veće ribe imaju veću predočnu i zaočnu udaljenost, manju veličinu oka i manju visinu ljusaka u bočnoj pruzi u odnosu na manje ribe. Negativna korelacija zabilježena kod najmanje i najveće visine tijela pokazuje da se tijelo ribe progresivno izdužuje. Merističke osobine šnjura pučinara s različitih područja Mediterana i sjeveroistočnog Atlantika uglavnom se podudaraju s podacima dobivenim u ovom radu

    State-Dependent Optical Lattices for the Strontium Optical Qubit

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    We demonstrate state-dependent optical lattices for the Sr optical qubit at the tune-out wavelength for its ground state. We tightly trap excited state atoms while suppressing the effect of the lattice on ground state atoms by more than four orders of magnitude. This highly independent control over the qubit states removes inelastic excited state collisions as the main obstacle for quantum simulation and computation schemes based on the Sr optical qubit. Our results also reveal large discrepancies in the atomic data used to calibrate the largest systematic effect of Sr optical lattice clocks.Comment: 6 pages, 4 figures + 6 pages supplemental materia

    Distribution of marine viruses in the Central and South Adriatic Sea

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    The seasonal distribution of marine viruses and their relationship with heterotrophic bacteria in the coastal and offshore area of the central and southern Adriatic were studied. Additionally, the percentage of high (HNA) and low (LNA) nucleic acid bacteria between the total number of bacteria and the distribution of heterotrophic nanoflagellates (HNF) as a major predator of bacteria were studied as well. The viral abundance ranged from 3.55 to 27.32 × 106 virus-like particles mL-1, and was on average 25-fold higher than bacterial abundances at all investigated stations. The highest viral abundances were found at coastal stations, especially in the area influenced by the rivers Krka and Jadro, whereas the lowest values were found in the open sea and in the coastal area of the southern Adriatic. No significant difference in relationship of viruses with HNA and LNA bacterial groups were established. The ratio between viruses and bacteria (VBR) was higher during the colder part of the year, which coincided with lower HNF abundance and vice versa during the warmer part of the year. This suggests that HNF grazing could be more important in controlling bacterial abundance during the warmer part of the year, and viral lysis during the colder part of the year

    Dynamics of picoplankton community from coastal waters to the open sea in the Central Adriatic

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    Flow cytometry was used to describe seasonal cycles of Prochlorococcus (Prochl), Synechococcus (Syn), picoeukaryotes and heterotrophic bacteria in the central Adriatic Sea along the trophic gradient from January to December 2010. All picoplankton parameters decreased from eutrophic to oligotrophic areas, while the biomass ratio of bacterial to autotrophic picoplankton showed an increase along the trophic gradient. Bacterial biomass ranged from 5.28 to 21.20 μg C l-1. Increased values were present during warmer seasons with the domination of low nucleic acid (LNA) group of bacteria. The high nucleic acid (HNA) bacterial group dominated during the winter and the spring. Bacterial production ranged from 0.09 -0.45 × 104 cells ml-1 h-1 .At coastal stations increased production was present during the winter and the spring and was more or less uniform at open sea stations. Biomasses of Syn and Prochl ranged from 0.16 to 11.47 µg C-1 l-1 and from 0.01 to 3.08 µg C l-1, respectively. They were elevated during the summer and the autumn at coastal stations and during the late winter at the open sea. Syn biomass always dominated over Prochl participating with 61.6-97.2% in biomass of cyanobacteria. Biomass of picoeukaryotes ranged from 1.21 to 21.85 µg C l-1 and was the highest during the winter. Their biomass notably prevailed in autotrophic picoplankton (APP) biomass over that of picocyanobacteria during the whole year. Autotrophic components (Prochl, Syn and picoeukaryotes) made greater contribution to the picoplankton biomass in mesotrophic and eutrophic areas, while heterotrophic bacteria became more important under oligotrophic conditions

    Response of GaN to energetic ion irradiation: conditions for ion track formation

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    We investigated the response of wurzite GaN thin films to energetic ion irradiation. Both swift heavy ions (92 MeV Xe23+, 23 MeV I6+) and highly charged ions (100 keV Xe40+) were used. After irradiation, the samples were investigated using atomic force microscopy, grazing incidence small angle X-ray scattering, Rutherford backscattering spectroscopy in channelling orientation and time of flight elastic recoil detection analysis. Only grazing incidence swift heavy ion irradiation induced changes on the surface of the GaN, when the appearance of nanoholes is accompanied by a notable loss of nitrogen. The results are discussed in the framework of the thermal spike model

    Influence of the coronavirus pandemic on execution of tasks by the coast guard of the Republic of Croatia

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    COVID-19 Pandemic, or better known as Coronavirus pandemic, is a current new disease of respiratory ways, and adjustment to life and work in the pandemic conditions is a challenge all organisations in the world, including military ones, have to face with. This paper analyses the influence of the COVID-19 pandemic on the intensity and implementation of surveillance and protection of national interests of the Republic of Croatia within the jurisdiction of the Coast Guard of the Republic of Croatia. A special attention is dedicated to determining how capable the Coast Guard of the Republic of Croatia is in executing all tasks in the pandemic circumstances. The analysis is carried out by comparing selected activities the Coast Guard of the Republic of Croatia carried out in 2020 with activities carried out in the period from 2015 to 2019. In the analysis of the effects which the COVID-9 pandemic had on the intensity and implementation of surveillance and protection of national interests of the Republic of Croatia within the jurisdiction of the Coast Guard, the following performed activities were observed: number of airplane flights, airplane fuel consumption, number of flight hours, number of engaged vessels, number of nautical miles sailed by vessels, number of registered vessel engine working hours, vessel fuel consumption, number of issued mandatory misdemeanour warrants. This paper has a goal to prove that the Coast Guard of the Republic of Croatia, having adjusted to a great extent to new operational circumstances, carries out all its tasks, and this can be best seen through a number of issued misdemeanour warrants, which means that the pandemic didn’t have a decisive negative impact on the work of the Coast Guard of the Republic of Croatia
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