197 research outputs found

    Multi-scale spatio-temporal patchiness of macrozoobenthos in the Sacca di Goro lagoon (Po River Delta, Italy)

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    1 - In this study, the macrobenthos from different habitats in the Sacca di Goro lagoon (Po River Delta, Italy) is analysed by following a multi-scale spatio-temporal approach, with the aim of evaluating the spatial patchiness and stability of macroinvertebrate assemblages in the lagoon. The scale similarity is examined by using a taxonomic metrics based on the Kullback-Leibler divergence and a related index of similarity.2 - Data were collected monthly during one year in four dominant habitat types, which were classified on the basis of main physiognomic traits (type of vegetation and anthropogenic impact). Three of the selected habitats were natural (macroalgal beds, bare sediment and Phragmitetum) and one anthropogenically modified (the licensed area for Manila clam farming). Each habitat was sampled in a variable number of stations representative of specific microhabitats, with three replicates each.3 - Of the 47 taxa identified, only few species were found exclusively in one habitat type, with low densities. No taxon was dominant in all the considered habitats.4 - The results show that, in spite of the large overlapping of species, the spatio-temporal dissimilarity within each habitat type was higher than expected on the basis of the common physiognomic traits. This suggests that local factors (mainly hydrodynamism, quality and quantity of vegetal matter) play a significant role in determining the structure of the macroinvertebrate assemblages.5 - The dissimilarity between habitats was significant and maintained all over the seasonal progression, indicating that the macroinvertebrate assemblages were steadily different. Each habitat allowed some specific taxa to maintain a significant population size, which is a prerequisite for preserving biodiversity.6 - The variety of vegetation types and hydrodynamic conditions in the lagoon emerges as crucial for sustaining biodiversity and capacity to recover from disturbances

    Ontogenetic shift in the trophic role of the invasive killer shrimp Dikerogammarus villosus: a stable isotope study

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    none5noThe introduction of the amphipod Dikerogammarus villosus in European fresh waters is to date recognized as a threat to the integrity of invaded communities. Predation by D. villosus on native benthic invertebrates is assumed as the key determinant of its ecological impact, yet available information describe the species as a primary consumer as well as a carnivore depending on local conditions. Here, we assessed the trophic position (TP) of D. villosus in Lake Trasimeno, a recently invaded lentic system in central Italy, using the CN isotopic signatures of individuals captured in winter spanning two orders of magnitude in body size. TP estimations were compared with those characterizing the native amphipod Echinogammarus veneris and other representative invertebrate predators. On average, D. villosus showed a trophic position higher than E. veneris, and comparable with that of odonate nymphs. An in-depth analysis revealed that large-sized individuals had a trophic position of 3.07, higher than odonates and close to that of the hirudinean predator Erpobdella octoculata, while small-sized specimens had a trophic position of 2.57, similar to that of E. veneris (2.41). These findings indicate that size-related ontogenetic shifts in dietary habits may per se vary the nature of the interaction between Dikerogammarus villosus and native invertebrates from competition to predation. Information collated from published isotopic studies corroborated the generality of our results. We conclude that intra-specific trophic flexibility may potentially amplify and make more multifaceted the impact of the species on other invertebrate species in invaded food webs.openMancini F.; De Giorgi R.; Ludovisi A.; Vizzini S.; Mancinelli G.Mancini, F.; De Giorgi, R.; Ludovisi, A.; Vizzini, S.; Mancinelli, G

    Isotopic Overlap of Invasive and Native Consumers in the Food Web of Lake Trasimeno (Central Italy)

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    An advanced characterization of the trophic niche of non-indigenous species (NIS) may provide useful information on their ecological impact on invaded communities. Here, we used carbon and nitrogen stable isotopes to estimate pairwise niche overlaps between non-indigenous and native consumers in the winter food web of Lake Trasimeno (central Italy). Overall, a relatively low pairwise overlap of isotopic niches was observed between NIS and native species. The only exception was the Louisiana crayfish Procambarus clarkii, which showed a relatively high and diffuse overlap with other native invertebrates. Our findings highlighted a high niche divergence between non-indigenous and native species in Lake Trasimeno, suggesting a potentially low degree of interspecific competition that may facilitate coexistence and, in turn, limit the strength of impacts. The divergent results obtained for the Louisiana crayfish indicate that additional control measures for this invasive species are needed to mitigate its impact on the Lake Trasimeno system

    On Rationality

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    Rationality is an enduring topic of interest across the disciplines and has become even more so, given the current crises that are unfolding in our society. The four books reviewed here, which are written by academics working in economics, political science, political theory and philosophy, provide an interdisciplinary engagement with the idea of rationality and the way it has shaped the institutional frameworks and global political economy of our time. Rational choice theory has certainly proved to be a useful analytic tool in certain contexts, and instrumental reason has been a key tenet of human progress in several periods of history, including the industrial revolution and the modernity that emerged in the nineteenth century. Given the complexity of our current challenges, however, is it time to ask whether this paradigm might be better complemented by more holistic and heterodox approaches? Hindmoor A and Taylor TY (2015) Rational Choice (Political Analysis), 2nd edn. London; New York: Palgrave Macmillan. Massumi (2015) The Power at the End of the Economy. Durham: Duke University Press. Brown (2015) Undoing the Demos: Neoliberalism’s Stealth Revolution. New York: Zone Books. Ludovisi SG (ed.) (2015) Critical Theory and the Challenge of Praxis: Beyond Reification. Farnham; Burlington, VT: Ashgate

    Les phlébotomes (Diptera-Psychodidae) de l'île de Chypre.II - Presence de Leishmania (Leishmania) infantum Nicolle, 1908 (zymodeme MON 1) chez Phlebotomus (Larroussius) tobbi Adler et Theodor, 1930

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    Dans le foyer leishmanien cypriote, les auteurs ont disseque 2910 femelles de phlebotomes appartenant a 11 especes : Phlebotomus papatasi, P. sergenti, P. jacusieli, P. alexandri, P. tobbi, P. galilaeus, P. mascittii, P. economidesi, Sergentomyia fallax, S. minuta et S. azizi . Les deux larroussius (P. galilaeus et P. tobbi ) sont les especes les plus abondantes. Elles representent plus de 60 % des captures realisees avec des pieges CDC. Des promastigotes ont ete observees chez un seul specimen appartenant a l'espece P. tobbi . Elles ont ete mises en culture puis identifiees selon la methode isoenzymatique. La souche de Leishmania isolee appartient a l'espece Leishmania infantum , zymodeme MON 1. Le meme zymodeme a ete aussi isole et identifie chez quatre chiens de l'ile. En l'absence des vecteurs habituels de L. infantum dans l'est mediterraneen (P. neglectus ef P. syriacus) et en raison de sa repartition a Chypre, P. tobbi constitue vraisemblablement un bon vecteur local. Sa faible anthropophilie expliquerait peut-etre le tres faible nombre de cas humains. Le role de P. galilaeus dans la transmission de la leishmaniose a Chypre reste a preciser

    Clinical and ultrasound characteristics of surgically removed adnexal lesions with largest diameter ≤ 2.5 cm: a pictorial essay

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    Objectives: To describe the ultrasound characteristics, indications for surgery and histological diagnoses of surgically removed adnexal masses with a largest diameter of ≤ 2.5 cm (very small tumors), to estimate the sensitivity and specificity of diagnosis of malignancy by subjective assessment of ultrasound images of very small tumors and to present a collection of ultrasound images of surgically removed very small tumors, with emphasis on those causing diagnostic difficulty. Methods: Information on surgically removed adnexal tumors with a largest diameter of ≤ 2.5 cm was retrieved from the ultrasound databases of seven participating centers. The ultrasound images were described using the International Ovarian Tumor Analysis terminology. The original diagnosis, based on subjective assessment of the ultrasound images by the ultrasound examiner, was used to calculate the sensitivity and specificity of diagnosis of malignancy. Results: Of the 129 identified adnexal masses with largest diameter ≤ 2.5 cm, 104 (81%) were benign, 15 (12%) borderline malignant and 10 (8%) invasive tumors. The main indication for performing surgery was suspicion of malignancy in 22% (23/104) of the benign tumors and in all 25 malignant tumors. None of the malignant tumors was a unilocular cyst (vs 50% of the benign tumors), all malignancies contained solid components (vs 43% of the benign tumors), 80% of the borderline tumors had papillary projections (vs 21% of the benign tumors and 20% of the invasive malignancies) and all invasive tumors and 80% of the borderline tumors were vascularized on color/power Doppler examination (vs 44% of the benign tumors). The ovarian crescent sign was present in 85% of the benign tumors, 80% of the borderline tumors and 50% of the invasive malignancies. The sensitivity of diagnosis of malignancy by subjective assessment of ultrasound images was 100% (25/25) and the specificity was 86% (89/104). Excluding unilocular cysts, the specificity was 71% (37/52). Analysis of images illustrated the difficulty in distinguishing benign from borderline very small cysts with papillations and benign from malignant very small well vascularized (color score 3 or 4) solid adnexal tumors. Conclusions: Very small malignant tumors manifest generally accepted ultrasound signs of malignancy. Small unilocular cysts are usually benign, while small non-unilocular masses, particularly ones with solid components, incur a risk of malignancy and pose a clinical dilemma

    Human Illnesses Caused by Opisthorchis felineus Flukes, Italy

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    We report 2 outbreaks of Opisthorchis felineus infection caused by the consumption of tench filets (Tinca tinca) from a lake in Italy. Of the 22 infected persons, 10 (45.4%) were asymptomatic. When present, symptoms (fever, nausea, abdominal pain, and myalgias) were mild. Eosinophilia occurred in all infected persons

    Enhanced B-cell differentiation and reduced proliferative capacity in chronic hepatitis C and chronic hepatitis B virus infections

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    BACKGROUND & AIMS: Chronic microial infections aare frequently associated with B-cell activation and polyclonal proliferation, potentially leading to autoimmunity and lymphoproliferative disorders. We assessed B-cell phenotype and function in chronic hepatitis B (HBV) and chronic hepatitis C (HCV) virus infection. METHODS: We studied 70 patients with chronic HCV infection, 34 with chronic HBV infection and 54 healthy controls, B-cell phenotype was assessed by flow cytometry using monoclonal antibodies specific for CD27, the CD69, CD71, and CD86 activation markers and the chemokine receptor CXCR3. Differentiation into immunoglobulin-producing cells (IPC) was analysed by ELISpot upon stimulation and with CD40 ligand+IL-10 as surrogate bystander T-cell help or CpG oligodeoxynucleotide+IL-2, as innate immunity signal. Proliferation was examined by cytometry using carboxyfluorescein diacetate succinimidyl ester (CFSE) after stimulation with CpG. RESULTS: A significantly higher proportion of B cells from both HCV-and HBV-infected patients expressed activation markers compared with controls and a positive correlation was found between CXCR3(+) B cells and HCV RNA values. Memory B cells from patients with chronic HCV and HBV infections showed enhanced differentiation into IPC compared with controls, although this was restricted to IgG and at a lower level in HCV-compared with HBV-infected patients. Moreover, patients' activated B cells displayed significantly lower proliferative ability compared to healthy donors despite low expression of the FcRL4 exhaustin marker. CONCLUSIONS: B-cell activation, but not exhaustion, is common in chronic viral hepatitis. However, enhanced B-cell differentiation and deficient proliferative capacity were not associated with commitment to terminal differentiation

    Ecosistemi di acque interne e di transizione

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    In questo contributo la vulnerabilità degli ecosistemi acquatici ai cambiamenti climatici è analizzata in relazione ai meccanismi di organizzazione e mantenimento della biodiversità e dei processi ecosistemici. Dai processi degli ecosistemi derivano funzioni che forniscono una serie di benefici o servizi per il genere umano (Daily et al., 2009). Tali servizi sono in larga misura dipendenti dalle componenti biologiche degli ecosistemi86. Negli ecosistemi acquatici i processi biogeochimici (ad es. denitrificazione batterica e assimilazione da parte della vegetazione acquatica), garantiscono l’abbattimento dei nutrienti, una funzione ecosistemica che produce il servizio di depurazione dell’acqua. Altri servizi sono la laminazione delle piene, la ricarica degli acquiferi, la regolazione del microclima locale, la produzione di risorse alimentari quali pesci, crostacei, ecc. (Jones, 2013). Le alterazioni degli ecosistemi, in particolare la perdita di specie e la diminuzione della biodiversità danneggiano questi servizi, con ricadute anche di tipo economico(si pensi, ad esempio, ai costi della depurazione dell’acqua destinata al consumo umano)
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