1,107 research outputs found

    Short communication: Morphological and genetic characterisation of selected Contracaecum (Nematoda: Anisakidae) larvae in Iran

    Get PDF
    In their life cycle, Contracaecum spp infect marine mammals and piscivorous birds as definitive hosts and crustaceans and a wide range of fish species as their intermediate hosts. Humans can accidentally be infected with larval stages of these nematodes, leading to a severe disease generally known as anisakidosis. The disease now is considered as an emergence zoonotic disease and therefore, these parasites attracted attention of scientists in different parts of the world and various aspects of their biology and lifecycle is being investigated. In Iran, there is a paucity of information on these socioeconomically important parasites. The present study is a preliminary study toward genetic characterisation and description of anisakid nematodes in Iran, using a combined molecular and morphological approach

    Biology and assessment of the painted sweetlips (Diagramma pictum (Thunberg, 1792)) and the spangled emperor (Lethrinus nebulosus (Forsskål, 1775)) in the southern Arabian Gulf

    Get PDF
    The population biology and status of the painted sweeplips (Diagramma pictum) and spangled emperor (Lethrinus nebulosus) in the southern Arabian Gulf were established by using a combination of size-frequency, biological, and size-at-age data. Transverse sections of sagittal otoliths were characterized by alternating translucent and opaque bands that were validated as annuli. Comparisons of growth characteristics showed that there were no significant differences (P>0.05) between sexes. There were well defined peaks in the reproductive cycle, spawning occurred from April to May for both species, and the mean size at which females attained sexual maturity was 31.8 cm fork length (LF) for D. pictum and 27.6 cm (LF) for L. nebulosus. The mean sizes at first capture (21.1 cm LF for D. pictum and 26.4 cm LF for L. nebulosus) were smaller than the sizes for both at first sexual maturity and those at which yield per recruit would be maximized. The range of fishing-induced mortality rates for D. pictum (0.37−0.62/yr) was substantially greater than the target (Fopt=0.07/yr) and limit (Flimit=0.09/ yr) estimates. The range of fishing-induced mortality rates for L. nebulosus (0.15/yr to 0.57/yr) was also in excess of biological reference points (Fopt=0.10/yr and Flimit=0.13/yr). In addition to growth overfishing, the stocks were considered to be recruitment overfished because the biomass per recruit was less than 20% of the unexploited levels for both species. The results of the study are important to fisheries management authorities in the region because they indicate that both a reduction in fishing effort and mesh-size regulations are required for the demersal trap fishery

    A space-time pseudospectral discretization method for solving diffusion optimal control problems with two-sided fractional derivatives

    Full text link
    We propose a direct numerical method for the solution of an optimal control problem governed by a two-side space-fractional diffusion equation. The presented method contains two main steps. In the first step, the space variable is discretized by using the Jacobi-Gauss pseudospectral discretization and, in this way, the original problem is transformed into a classical integer-order optimal control problem. The main challenge, which we faced in this step, is to derive the left and right fractional differentiation matrices. In this respect, novel techniques for derivation of these matrices are presented. In the second step, the Legendre-Gauss-Radau pseudospectral method is employed. With these two steps, the original problem is converted into a convex quadratic optimization problem, which can be solved efficiently by available methods. Our approach can be easily implemented and extended to cover fractional optimal control problems with state constraints. Five test examples are provided to demonstrate the efficiency and validity of the presented method. The results show that our method reaches the solutions with good accuracy and a low CPU time.Comment: This is a preprint of a paper whose final and definite form is with 'Journal of Vibration and Control', available from [http://journals.sagepub.com/home/jvc]. Submitted 02-June-2018; Revised 03-Sept-2018; Accepted 12-Oct-201

    Occurrence and description of Dactylogyrus sphyrna Linstow, 1878 (Monogenea: Dactylogyride) on the gills of an Iranian endemic fish Leucisucs persidis Coad, 1981 as a new host

    Get PDF
    Leuciscus persidis as Iranian endemic fish in Kaftar lake and its headwaters (Mesopotamian subregion, Kor-Neiriz basin and Shadkam river) has been infected with a species of Dactylogyrus sphyrna. Comparison of collected parasites with Euro-Asian subregion showed that the similarity of them is more than their differences, although a little difference between them was observed. In this paper also introduce of Dactylogyrus sphyrna parasite to the new host is discussed

    Simulation and Optimization of Coal Gasification in a Moving-bed Reactor to Produce Synthesis Gas Suitable for Methanol Production Unit

    Get PDF
    This paper presents process simulation and optimization of coal gasification process in a moving-bed reactor using Pittsburgh No. 8 coal as feed. The system of differential equations for the mass and energy balances was solved using 4th-order Runge-Kutta method and optimized by non-dominated sorting genetic algorithm-II (NSGA-II) method. The simulation was used to predict solid and gas temperature profile and gas composition along the reactor. The simulation results were compared successfully with experimental data relevant to Westfield plant in Scotland. In addition, the effect of operating parameters such as coal-to-oxygen molar ratio, steam-to-oxygen molar ratio, inlet gas temperature, reactor pressure, and oxygen mole fraction in inlet air on amount of synthesis gas (syngas) production, hydrogen to carbon monoxide molar ratio (HCMR) in produced syngas, and coal conversion was investigated. Finally, the reactor performance was optimized to produce the highest syngas production with a HCMR of two using NSGA-II method. This work is licensed under a Creative Commons Attribution 4.0 International License

    Evaluation of the middle ear in water buffaloes (Bubalus bubalis) by gross anatomy and cone-beam computed tomography

    Get PDF
    Background: The purpose of this study was to provide a description of gross middle ear morphology in water buffaloes, augmented with additional data on the osseous structures of middle ear derived from cone-beam computed tomography (CBCT). Materials and methods: Skulls of 10 young adult male water buffaloes were used to examine their middle ears. Results: Anatomical features noted included the presence of tympanic cells in the tympanic bulla, the location of malleus head and neck, and all of incus in the dorsal epitympanic recess, the oval tympanic membrane, absence of a prominent notch on the articular surface of malleus, positional variations of the lateral process of malleus relative to the muscular process and muscular process relative to the rostral process of malleus, absence of complete coverage of the articular facet of malleus head by incus body, and presence of the lenticular process of incus. In CBCT images, the osseous part of external acoustic meatus, the petrous part of temporal bone and the details of the ossicles were seen, except for stapes. Conclusions: Although tympanic membrane, malleus and stapes of water buffaloes are similar to those of ox, the incus of water buffaloes is more similar to that of goats. The heaviest ossicles among the ruminants studied belonged to water buffaloes; the mean length of malleus head and neck, total length and width of incus body as well as length of stapes head were greatest in water buffaloes too. The auditory ossicles of water buffaloes show ‘transitional type’ morphological characteristics. These features suggest a relatively wide frequency range of hearing, but not one biased towards especially low or especially high frequencies

    Effects of water temperature and migration time on some fecundity indices and fertilization rate of female Kutum, Rutilus frisii kutum,migratory to Shiroud River in the southwest Caspian Sea

    Get PDF
    Kutum, Rutilus frisii kutum, is an commercially important fish in the Caspian Sea. The fish enters the rivers leading to the Caspian Sea for spawning. One of these rivers is Shiroud River. In the artificial propagation process of Kutum, different factors are involved in quality and quantity of female broods eggs and also in the best temperature and migration time for spawning. The influence of temperature and migration time on some fecundity indices and fertilization rate of female kutum in Shiroud River was studied in the spawning season. In this study, 90 individual females were studied from February to May 2007. Averages of total length, weight and age were 43.26 cm, 832.08 g, and 4.41 respectively. Results showed that maximum egg diameter (1.86 mm), number of eggs per each gram of body weight (309.12), relative fecundity (56.21) and fertilization rate (95.82 %) were obtained from 5 to 20 April (15.95°C). Maximum ovary weight (201.00 g) and absolute fecundity of eggs (49987.18) were obtained from 6 to 20 March (17.74°C). Relationship between temperature and migration time and fecundity indices was linear and weak
    corecore