13,964 research outputs found

    Stock assessment of the deep-water spiny lobster Palinurus delagoae, off Mozambique

    Get PDF
    Preliminary estimates of growth parameters and mortality are presented for the deep-water spiny lobster Palinurus delagoae fished off Mozambique. The length-converted catch curve shows three levels of total mortality (year-1): Z=2.9 for the smaller sizes; Z=1.4 for intermediate, and Z=0.6 for the larger lobsters. These results are confirmed by a length-structured virtual population analysis. Yield-per-recruit analysis suggests that a long-term yield, at least 50% higher than the present one, could be obtained by increasing the mean size at first capture from about 6 cm (carapace length) to about 10 cm

    Leucena: alternativa forrageira de alta qualidade para caprinos e ovinos.

    Get PDF
    bitstream/item/53179/1/Folder-Leucena.pf.pd

    Informaçāo preliminar sobre lagosta de profundidade

    Get PDF
    The species Palinurus delagoae is distributed at 17 °00' S of latitude, at a depth greater than 200 meters. However the main area with a fishing intensity station is located at 22°00'S of latitude from 200 and 400 meters. The fishing of these resources is made with cages and trawling nets

    Surficial sediment texture database for the south-western Iberian Atlantic margin

    Get PDF
    Assessing the impact of changes on the environment driven by natural or anthropogenic forcers includes the comparison between antecedent and post-event conditions. The latter is particularly relevant in order to better understand to which extent those changes actually impact or alter a particular environment and associated services and to determine the resilience of a system. In this regard, it becomes essential to create or provide databases to inform about baseline conditions. Here, we present a database that integrates surficial sediment samples collected and analysed for textural characterization within the framework of a series of research projects over circa 20 years. Collected samples along the south-western Atlantic margin of the Iberian Peninsula extend from estuaries and beaches to the adjacent continental shelf. For the case of the more dynamic environments, namely coastal sandy barriers, samples were repeated over time in order to capture the intrinsic variability of the system. Examples of the utility of this data set for a variety of purposes and environments are also included within this paper through three examples. Therefore, here we show the added value of the database as it can be used to assess the impact of a particular event or activity at an estuary by providing baseline conditions, evaluate the continental shelf sediment suitability for nourishment activities, or contribute to the understanding of the morphodynamics and classification of beaches. Finally, it is worth stating the importance of such databases to analyse medium- to long-term variability as the one induced by sea level rise, changes in storminess, or human activities.FCT Investigator programme [IF/01047/2014]info:eu-repo/semantics/publishedVersio

    Standard map in magnetized relativistic systems: fixed points and regular acceleration

    Get PDF
    We investigate the concept of a standard map for the interaction of relativistic particles and electrostatic waves of arbitrary amplitudes, under the action of external magnetic fields. The map is adequate for physical settings where waves and particles interact impulsively, and allows for a series of analytical result to be exactly obtained. Unlike the traditional form of the standard map, the present map is nonlinear in the wave amplitude and displays a series of peculiar properties. Among these properties we discuss the relation involving fixed points of the maps and accelerator regimes.Comment: Work to appear in Phys. Rev. E. 2 figure

    Snapshot of macroalgae and fish assemblages in temperate reefs in the Southern European Atlantic Ecoregion

    Get PDF
    Most of the biodiversity studies in the South European Atlantic Shelf ecoregion are limited to shallow subtidal or intertidal habitats, while deeper reef habitats, also of relevant ecological importance, are particularly understudied. Macroalgal communities, associated fauna, and sea surface temperature were studied in deep reefs (25-30 m) at two locations in this ecoregion: Parcel, North of Portugal (41 degrees N), and Tarifa, Southern Spain (35 degrees N). Specifically, algal assemblages were assessed using biomass collection and associated ichthyofauna was assessed using visual census techniques using scuba. Seawater surface temperature was higher (>3 degrees C) in the southern region-Tarifa, compared to the northern region-Parcel. Our survey revealed 18 fish species and 23 algae species. The highest abundance of cold-water species (both macroalgae and fish species) was recorded in Parcel and warm-water species were dominant in Tarifa. In light of climate global trends, both regions might experience biodiversity shifts towards tropicalization. Current knowledge on their biodiversity is imperative to further evaluate potential shifts.info:eu-repo/semantics/publishedVersio

    Vaccines for Canine Leishmaniasis

    Get PDF
    Leishmaniasis is the third most important vector-borne disease worldwide. Visceral leishmaniasis (VL) is a severe and frequently lethal protozoan disease of increasing incidence and severity due to infected human and dog migration, new geographical distribution of the insect due to global warming, coinfection with immunosuppressive diseases, and poverty. The disease is an anthroponosis in India and Central Africa and a canid zoonosis (ZVL) in the Americas, the Middle East, Central Asia, China, and the Mediterranean. The ZVL epidemic has been controlled by one or more measures including the culling of infected dogs, treatment of human cases, and insecticidal treatment of homes and dogs. However, the use of vaccines is considered the most cost–effective control tool for human and canine disease. Since the severity of the disease is related to the generation of T-cell immunosuppression, effective vaccines should be capable of sustaining or enhancing the T-cell immunity. In this review we summarize the clinical and parasitological characteristics of ZVL with special focus on the cellular and humoral canine immune response and review state-of-the-art vaccine development against human and canine VL. Experimental vaccination against leishmaniasis has evolved from the practice of leishmanization with living parasites to vaccination with crude lysates, native parasite extracts to recombinant and DNA vaccination. Although more than 30 defined vaccines have been studied in laboratory models no human formulation has been licensed so far; however three second-generation canine vaccines have already been registered. As expected for a zoonotic disease, the recent preventive vaccination of dogs in Brazil has led to a reduction in the incidence of canine and human disease. The recent identification of several Leishmania proteins with T-cell epitopes anticipates development of a multiprotein vaccine that will be capable of protecting both humans and dogs against VL

    Alternate islands of multiple isochronous chains in wave-particle interactions

    Full text link
    We analyze the dynamics of a relativistic particle moving in a uniform magnetic field and perturbed by a standing electrostatic wave. We show that a pulsed wave produces an infinite number of perturbative terms with the same winding number, which may generate islands in the same region of phase space. As a consequence, the number of isochronous island chains varies as a function of the wave parameters. We observe that in all the resonances, the number of chains is related to the amplitude of the various resonant terms. We determine analytically the position of the periodic points and the number of island chains as a function of the wave number and wave period. Such information is very important when one is concerned with regular particle acceleration, since it is necessary to adjust the initial conditions of the particle to obtain the maximum acceleration.Comment: Submitte
    corecore