43 research outputs found

    Distribution of skates and sharks in the North Sea: 112 years of change

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    How have North Sea skate and shark assemblages changed since the early 20th century when bottom trawling became widespread, whilst their environment became increasingly impacted by fishing, climate change, habitat degradation and other anthropogenic pressures? This article examines long-term changes in the distribution and occurrence of the elasmobranch assemblage of the southern North Sea, based on extensive historical time series (1902–2013) of fishery-independent survey data. In general, larger species (thornback ray, tope, spurdog) exhibited long-term declines, and the largest (common skate complex) became locally extirpated (as did angelshark). Smaller species increased (spotted and starry ray, lesser-spotted dogfish) as did smooth-hound, likely benefiting from greater resilience to fishing and/or climate change. This indicates a fundamental shift from historical dominance of larger, commercially valuable species to current prevalence of smaller, more productive species often of low commercial value. In recent years, however, some trends have reversed, with the (cold-water associated) starry ray now declining and thornback ray increasing. This shift may be attributed to (i) fishing, including mechanised beam trawling introduced in the 1960s–1970s, and historical target fisheries for elasmobranchs; (ii) climate change, currently favouring warm-water above cold-water species; and (iii) habitat loss, including potential degradation of coastal and outer estuarine nursery habitats. The same anthropogenic pressures, here documented to have impacted North Sea elasmobranchs over the past century, are likewise impacting shelf seas worldwide and may increase in the future; therefore, parallel changes in elasmobranch communities in other regions are to be expected

    Effects of acute and chronic temperature changes on the functional responses of the dogfish Scyliorhinus canicula (Linnaeus, 1758) towards amphipod prey Echinogammarus marinus (Leach, 1815)

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    Predation is a strong driver of population dynamics and community structure and it is essential to reliably quantify and predict predation impacts on prey populations in a changing thermal landscape. Here, we used comparative functional response analyses to assess how predator-prey interactions between dogfish and invertebrate prey change under different warming scenarios. The Functional Response Type, attack rate, handling time and maximum feeding rate estimates were calculated for Scyliorhinus canicula preying upon Echinogammarus marinus under temperatures of 11.3 °C and 16.3 °C, which represent both the potential daily variation and predicted higher summer temperatures within Strangford Lough, N. Ireland. A two x two design of “Predator Acclimated”, “Prey Acclimated”, “Both Acclimated”, and “Both Unacclimated” was implemented to test functional responses to temperature rise. Attack rate was higher at 11.3 °C than at 16.3 °C, but handling time was lower and maximum feeding rates were higher at 16.3 °C. Non-acclimated predators had similar maximum feeding rate towards non-acclimated and acclimated prey, whereas acclimated predators had significantly higher maximum feeding rates towards acclimated prey as compared to non-acclimated prey. Results suggests that the predator attack rate is decreased by increasing temperature but when both predator and prey are acclimated the shorter handling times considerably increase predator impact. The functional response of the fish changed from Type II to Type III with an increase in temperature, except when only the prey were acclimated. This change from population destabilizing Type II to more stabilizing Type III could confer protection to prey at low densities but increase the maximum feeding rate by Scyliorhinus canicula in the future. However, predator movement between different thermal regimes may maintain a Type II response, albeit with a lower maximum feeding rate. This has implications for the way the increasing population Scyliorhinus canicula in the Irish Sea may exploit valuable fisheries stocks in the future

    Stable landings mask irreversible community reorganizations in an overexploited Mediterranean ecosystem

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    Cumulative human pressures and climate change can induce nonlinear discontinuous dynamics in ecosystems, known as regime shifts. Regime shifts typically imply hysteresis, a lacking or delayed system response when pressures are reverted, which can frustrate restoration efforts. Here, we investigate whether the northern Adriatic Sea fish and macroinvertebrate community, as depicted by commercial fishery landings, has undergone regime shifts over the last 40 years, and the reversibility of such changes. We use a stochastic cusp model to show that, under the interactive effect of fishing pressure and water warming, the community reorganized through discontinuous changes. We found that part of the community has now reached a new stable state, implying that a recovery towards previous baselines might be impossible. Interestingly, total landings remained constant across decades, masking the low resilience of the community. Our study reveals the importance of carefully assessing regime shifts and resilience in marine ecosystems under cumulative pressures and advocates for their inclusion into management

    Immunomodulating activity of RU 41740 : in vitro and in vivo studies on human lymphocytes

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    A group of institutionalized elderly subjects, selected on the basis of their skin hypoergy and displaying different kinds of T and B lymphocyte impairments has been chosen as a model to verify the in vivo immunopotentiating activity of RU 41740 on human lymphocytes. Oral treatment with the drug was able to: (a) restore or improve the cutaneous delayed hypersensitivity to recall antigens; (b) significantly increase the blastigenetic response to mitogenic and submitogenic doses of PHA and PWM and (c) improve the in vitro PWM-induced synthesis of IgG and IgM. The immunooharmacological activity of RU 41740 appeared to persist three months after the end of therapy, without any direct stimulating activity on the peripheral blood lymphocytes. The in vitro results seem to suggest that peripheral lymphocytes are not directly influenced by the drug

    Morphing electroadhesive interface to manipulate uncooperative objects

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    The possibility of handling uncooperative objects, i.e. objects not equipped with any features that can aid their manipulation, is of particular interest for both terrestrial and space robotic applications. In this framework, this paper deals with the development and testing of a smart material substrate, which can be integrated into an end-effector device, where morphing and electro-adhesive capabilities are combined to allow the manipulation of uncooperative objects of different shapes and materials. Compliance and adhesion properties are obtained by creating a conductive pattern of electrodes embodied on the surface of a polymeric substrate. On one hand, the polymeric material, activated by a change in temperature, can adapt to any shape when it is heated, and maintain the deformed shape after being cooled, even when the load is removed, becoming compliant with the objects surface. On the other hand, the conductive pattern is responsible for the adhesive effect: when a high voltage is applied, the electric field generated induces an opposite charge on the objects surface establishing reversible attraction forces. Furthermore, the conductive pattern could be used to activate the morphing behaviour when the manipulator and the target object come into contact. A resistive-electroadhesive pad is realized and some tests are performed to verify the heating behavior of the electrodes and the electroadhesion forces achievable. Morphing tests are also performed to verify the ability of the polymeric substrate to maintain the deformed shape after coolin

    Contribution to the symposium: 'sustainable use of baltic sea resources' original article a three-dimensional view on biodiversity changes: Spatial, temporal, and functional perspectives on fish communities in the baltic sea

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    Fisheries and marine ecosystem-based management requires a holistic understanding of the dynamics of fish communities and their responses to changes in environmental conditions. Environmental conditions can simultaneously shape the spatial distribution and the temporal dynamics of a population, which together can trigger changes in the functional structure of communities. Here, we developed a comprehensive framework based on complementary multivariate statistical methodologies to simultaneously investigate the effects of environmental conditions on the spatial, temporal and functional dynamics of species assemblages. The framework is tested using survey data collected during more than 4000 fisheries hauls over the Baltic Sea between 2001 and 2016. The approach revealed the Baltic fish community to be structured into three sub-assemblages along a strong and temporally stable salinity gradient decreasing from West to the East. Additionally, we highlight a mismatch between species and functional richness associated with a lower functional redundancy in the Baltic Proper compared with other sub-areas, suggesting an ecosystem more susceptible to external pressures. Based on a large dataset of community data analysed in an innovative and comprehensive way, we could disentangle the effects of environmental changes on the structure of biotic communities-key information for the management and conservation of ecosystems. VC International Council for the Exploration of the Sea 2018

    Immunoprophylaxis in "septic risk" patients undergoing surgery for gastrointestinal cancer. Results of a randomized, multicenter clinical trial.

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    Abstract The results of a randomized, multicenter clinical trial of immunoprophylaxis of post-operative infections with intravenous Immunoglobulins (IVIG) (Sandoglobulin) in "septic-risk" patients undergoing surgery for gastrointestinal cancer are presented. "Septic-risk" patients were selected by an original multiparametric test based on delayed hypersensitivity skin testing and serum protein electrophoretic sub-fractions. This screening test had shown 76% positive predictivity in a previous validation assessment. In the present study, 159 "septic-risk" patients were selected prospectively from 369 patients undergoing colo-rectal (colon) and other kinds of gastrointestinal (non-colon) oncologic surgery: 80 "septic-risk" patients were included in the colon and 79 in the non-colon group. Immunoprophylaxis with IVIG (15 g on the day prior to operation, on the 1st and 5th postoperative days) was randomly associated with antibiotic prophylaxis (cefoxitin: 2 g one hour prior to, followed by 2 g at the end of operation plus 2 g every six hours for 24 hours) in colon surgery while the prophylactic schedule in non-colon surgery was only based on random administration of IVIG, at the same dosage as in the colon group. There was a clear-cut reduction of post-operative infections both in colon and non-colon "septic-risk" patients who had IVIG prophylaxis; in the colon group, 37 and 21 infections (P < 0.004) in antibiotic (A) versus IVIG plus antibiotic (IVIG + A) subset, respectively; in the non-colon group, 33 and 19 infections (P < 0.01) in control (C) versus (IVIG) subset, respectively.(ABSTRACT TRUNCATED AT 250 WORDS

    Estimating the impact of rare disorders on population health: an Italian experience

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    The study estimates the impact of RD on population\u2019s health comparing two independent sources of data monitoring the same population. ICD- based current statistics can be used to roughly estimate the number of af- fected patients in a defined are
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