705 research outputs found

    Zygoparity and sex steroid hormone profiles in bluemouth Helicolenus dactylopterus

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    Two hundred and seven individuals (103 females and 104 males) of bluemouth Helicolenus dactylopterus (Scorpaeniformes, Sebastidae), a commercially important deep-water species with an unusual reproductive strategy, from the eastern Atlantic Ocean ranging from 139 to 375 cm total length (L-T) were analysed from September 2011 to October 2012. The analysis included gonad maturity phases and blood-plasma levels of oestradiol-17 (E-2), 11-ketotestosterone (11-KT) and 17,20-dihydroxypregn-4-en-3-one (17,20-P). Results confirmed the existence of an annual reproductive cycle with asynchrony between females and males and a spawning season from January to May. A pronounced peak in 17,20-P in October for both sexes was associated with possible mating behaviour and recent copula. Levels of E-2 increased preceding the elevation of the gonado-somatic index during ovarian growth and were lower during regression and regeneration. The frequency distribution of oocyte-embryonic stages and variation of hormone levels suggest the existence of daily rhythms. Fertilization was detected between 2000-0000 and 0800-1200 h and spawning took place throughout the day peaking between 2000 and 0000 h. The cyclic pattern of sex steroids and ovarian recruitment provides a new insight into the reproductive strategy of this species.Fundacao para a Ciencia e a Tecnologia SFRH/BPD/108917/2015, SFRH/BD/92769/2013info:eu-repo/semantics/publishedVersio

    Oocyte Development of Scalloped Perchlet, Ambassis Nalua (Hamilton 1822)

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    Ikan seriding (Ambassis nalua) merupakan salah satu jenis ikan di perairan Teluk Pabean, Indramayu yang berukuran kecil, transparan dan tersedia dalam jumlah melimpah. Penelitian ini bertujuan untuk melihat perkembangan sel telur secara histologis dan menentukan tipe pemijahan ikan seriding. Ikan seriding didapatkan dari hasil tangkapan nelayan di Teluk Pabean, kemudian gonad contoh diawetkan dengan menggunakan larutan BNF (Buffer Neutral Formalin). Preparat histo-logis sel telur dibuat dengan metode pewarnaan HE, kemudian diamati dibawah mikroskop berkamera. Tahapan perkembangan oosit pada ikan seriding yaitu kromatin nukleus dan perinuklear (tahap pertumbuhan awal), kortikal alveoli, vitelo-genesis, dan pematangan. Tahapan tersebut menunjukkan bahwa ikan seriding merupakan tipe ikan yang memijah secara bertahap

    Adaptation and Evaluation of the Multisplitting-Newton and Waveform Relaxation Methods Over Distributed Volatile Environments

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    International audienceThis paper presents new adaptations of two methods that solve large differential equations systems, to the grid context. The first method isbased on the Multisplitting concept and the second on the Waveform Relaxation concept. Their adaptations are implemented according to the asynchronous iteration model which is well suited to volatile architectures that suffer from high latency networks. Many experiments were conducted to evaluate and compare the accuracy and performance of both methods while solving the advection-diffusion problem over heterogeneous, distributed and volatile architectures. The JACEP2P-V2 middleware provided the fault tolerant asynchronous environment, required for these experiments

    A General Overview on Some Aspects of Fish Reproduction

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    - Reproduction is one of the important physiological systems that are crucial in the life cycle of living organisms including fish. The main objective of the reproduction is to maintain the existence of the species and therefore fish have a strategies and tactics to achieve this objective. The reproduction behaviours are important to be studied in relation to know the population dynamic of fishes and their spawning seasons. This information is very crucial in relation to the development of breeding technology for aquaculture and conservation (restocking) purposes. This paper reviews the reproductive strategy, fecundity and spawning frequency of fishes

    A Calculus of Bounded Capacities

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    Resource control has attracted increasing interest in foundational research on distributed systems. This paper focuses on space control and develops an analysis of space usage in the context of an ambient-like calculus with bounded capacities and weighed processes, where migration and activation require space. A type system complements the dynamics of the calculus by providing static guarantees that the intended capacity bounds are preserved throughout the computation

    Description of the ovarian follicle maturation of the migratory adult female Bulatmai barbel (Luciobarbus capito, Güldenstädt 1772) in captivity

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    The study aimed to investigate the maturation process of ovarian follicles and ovary structure of migratory form of female Bulatmai barbel (Lucioarbus capito). The histology of oogenesis coincided with that known from most teleosts. The ovarian structure was found to be cytovarian. The development of the oocytes is started from early May along with spawning and the degeneration of matured oocytes. The oocytes’ development continues during summer and early fall and the ovary undergoes a dormant period in fall and winter. In the next spring, the next phase of oocyte development started along with the rising of water-temperature. During May and June the development of the oocytes is completed and the final maturation can occur if the environmental conditions are suitable. The Gonadosomatic Index values show a concordance with the oocyts maturation in the ovaries. The reproductive strategy, with long spawning periods during spawning season, found to be batch spawner with asynchronous oogenesis pattern. The results show that it can be matured while captivity

    Enabling Interactive Analytics of Secure Data using Cloud Kotta

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    Research, especially in the social sciences and humanities, is increasingly reliant on the application of data science methods to analyze large amounts of (often private) data. Secure data enclaves provide a solution for managing and analyzing private data. However, such enclaves do not readily support discovery science---a form of exploratory or interactive analysis by which researchers execute a range of (sometimes large) analyses in an iterative and collaborative manner. The batch computing model offered by many data enclaves is well suited to executing large compute tasks; however it is far from ideal for day-to-day discovery science. As researchers must submit jobs to queues and wait for results, the high latencies inherent in queue-based, batch computing systems hinder interactive analysis. In this paper we describe how we have augmented the Cloud Kotta secure data enclave to support collaborative and interactive analysis of sensitive data. Our model uses Jupyter notebooks as a flexible analysis environment and Python language constructs to support the execution of arbitrary functions on private data within this secure framework.Comment: To appear in Proceedings of Workshop on Scientific Cloud Computing, Washington, DC USA, June 2017 (ScienceCloud 2017), 7 page

    Reproductive biology of Chela fasciata Silas – an endemic ornamental barb of the of Western Ghats of India

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    Reproductive biology of Chela fasciata, an ornamental cyprinid fish endemic to the Western Ghats of Kerala, was studied from144 specimens (94 females and 50 males) ranging in size from 26.0 to 82.0 mm. The ovaries showed asynchronous oocyte development. The first mature female appeared at 40–45 mm total length (TL) and male at 25–30 mm TL. The size at first maturity estimated was 45.75 and 36.25 mm for females and males respectively. All females were mature at 60 mm TL and males at 45 mm TL. C. fasciata was found to be a multiple spawner with a protracted spawning season; the individuals spawn intermittently. Absolute fecundity ranged from 2669 to 4437 in fishes of size range 49.5 to 82 mm TL. The number and size of eggs were found to be directly proportional to the size and age of the fish. Fecundity showed a positive linear relationship (p<0.05) with the length and weight of both the fish and ovary

    Review of the spatial and temporal distribution by life stage for 19 North Sea fish species

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    Considering the increase in human activity in the North Sea, particularly cargo shipping and the rapidly expanding construction and operation of oil platforms and wind farms, as well as the continued use of the area for military purposes, fisheries and sand extraction, there is a growing concern about the potentially harmful impacts of such anthropogenic activities on marine life. Particular concerns have been raised about the effect of loud impulse sounds and high noise levels, which may affect marine animal life in different ways: habitat use, such as feeding and migration, and reproduction patterns may be disturbed. In the extreme case animals may suffer from sub-lethal or lethal physical damage such as hearing loss and disrupted swim ladders. Knowledge of the spatial distribution and seasonal patterns in the presence of different life stages of marine species is therefore critical for assessing to what extent the dispersion of marine life overlaps with the distribution of human activities and for estimating how potentially harmful impacts can be mitigated both spatially and temporally. The aim of this desk study is consequently to provide a concise overview of existing information on seasonal patterns in the dispersion of fish species in the North Sea, in particular by highlighting the knowledge gaps
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