38 research outputs found

    Implications of Extreme Life Span in Clonal Organisms: Millenary Clones in Meadows of the Threatened Seagrass Posidonia oceanica

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    The maximum size and age that clonal organisms can reach remains poorly known, although we do know that the largest natural clones can extend over hundreds or thousands of metres and potentially live for centuries. We made a review of findings to date, which reveal that the maximum clone age and size estimates reported in the literature are typically limited by the scale of sampling, and may grossly underestimate the maximum age and size of clonal organisms. A case study presented here shows the occurrence of clones of slow-growing marine angiosperm Posidonia oceanica at spatial scales ranging from metres to hundreds of kilometres, using microsatellites on 1544 sampling units from a total of 40 locations across the Mediterranean Sea. This analysis revealed the presence, with a prevalence of 3.5 to 8.9%, of very large clones spreading over one to several (up to 15) kilometres at the different locations. Using estimates from field studies and models of the clonal growth of P. oceanica, we estimated these large clones to be hundreds to thousands of years old, suggesting the evolution of general purpose genotypes with large phenotypic plasticity in this species. These results, obtained combining genetics, demography and model-based calculations, question present knowledge and understanding of the spreading capacity and life span of plant clones. These findings call for further research on these life history traits associated with clonality, considering their possible ecological and evolutionary implications

    A Catalytic Mechanism for Cysteine N-Terminal Nucleophile Hydrolases, as Revealed by Free Energy Simulations

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    The N-terminal nucleophile (Ntn) hydrolases are a superfamily of enzymes specialized in the hydrolytic cleavage of amide bonds. Even though several members of this family are emerging as innovative drug targets for cancer, inflammation, and pain, the processes through which they catalyze amide hydrolysis remains poorly understood. In particular, the catalytic reactions of cysteine Ntn-hydrolases have never been investigated from a mechanistic point of view. In the present study, we used free energy simulations in the quantum mechanics/molecular mechanics framework to determine the reaction mechanism of amide hydrolysis catalyzed by the prototypical cysteine Ntn-hydrolase, conjugated bile acid hydrolase (CBAH). The computational analyses, which were confirmed in water and using different CBAH mutants, revealed the existence of a chair-like transition state, which might be one of the specific features of the catalytic cycle of Ntn-hydrolases. Our results offer new insights on Ntn-mediated hydrolysis and suggest possible strategies for the creation of therapeutically useful inhibitors

    Recent evolutions of gender, state feminism and care models in Latin America and Europe

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    Production of INCASI Project H2020-MSCA-RISE-2015 GA 691004This chapter presents and characterises the way in which, in the twenty-first century, after years of feminist struggles inside and outside of institutions, gender relations are organised in the different countries of the INCASI project (on the European side, Spain, Italy, Finland, France and the United Kingdom, on the side of the South American Southern Cone, Argentina, Brazil, Chile and Uruguay). It pays special attention to the implementation of feminist issues on political agendas, and in particular the assignment of women to unpaid care work-an aspect of the power continuum that we look to relate to other aspects. Gradually and for almost a century all countries in both continents have granted women the status of subjects, citizens and employees. However, the conditions, challenges and timelines of this process differ considerably from one continent to another, so they need to be addressed separately. The neoliberal era did not have the same impact in Europe as it did in South America (nor was it exactly the same between particular European countries or among South American ones)

    Alignment of the ALICE Inner Tracking System with cosmic-ray tracks

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    37 pages, 15 figures, revised version, accepted by JINSTALICE (A Large Ion Collider Experiment) is the LHC (Large Hadron Collider) experiment devoted to investigating the strongly interacting matter created in nucleus-nucleus collisions at the LHC energies. The ALICE ITS, Inner Tracking System, consists of six cylindrical layers of silicon detectors with three different technologies; in the outward direction: two layers of pixel detectors, two layers each of drift, and strip detectors. The number of parameters to be determined in the spatial alignment of the 2198 sensor modules of the ITS is about 13,000. The target alignment precision is well below 10 micron in some cases (pixels). The sources of alignment information include survey measurements, and the reconstructed tracks from cosmic rays and from proton-proton collisions. The main track-based alignment method uses the Millepede global approach. An iterative local method was developed and used as well. We present the results obtained for the ITS alignment using about 10^5 charged tracks from cosmic rays that have been collected during summer 2008, with the ALICE solenoidal magnet switched off.Peer reviewe

    Medical teachers' attitudes towards science and motivational orientation for medical research

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    BACKGROUND: Research is an important motivating factor for pursuing a career in academic medicine, but the relation between motivation and other factors involved in scientific research are not clear. ----- PURPOSE: To explore the motivational orientation for doing research and its relation with attitudes towards science and publication practice among members of faculty at a medical school. ----- METHODS: We used a Science Attitude Survey and the Work Preference Inventory (intrinsic and extrinsic motivational orientation using 4 Likert-type scales of motivation, possible range 1-5) to survey two groups of teachers at the Zagreb University School of Medicine (n = 327, 66% response rate): professors, elected to tenure-track positions (n = 150), and instructor/research fellows working on or just completing their thesis (n = 177). RESULTS: Overall, teachers scored highest on the Enjoyment subscale of intrinsic motivational orientation (mean score +/- standard deviation 4.3 +/- 0.42 for professors vs 4.1 +/- 0.42 for instructors/research fellows, P = 0.001, t-test). Professors also scored higher than instructors/research fellows on the Challenge subscale of intrinsic motivational orientation (3.8 +/- 0.55 vs. 3.5 +/- 0.64, P < 0.001, t-test), whereas instructors/research fellows scored higher on the Compensation subscale of extrinsic motivational orientation (3.5 +/- 0.74 vs. 3.1 +/- 0.71, P < 0.001, t-test). Multiple linear regression analysis showed that the number of publications was positively associated with scores on the Science Attitude Survey and the Challenge subscale of intrinsic motivation, and negatively associated with scores on the Compensation subscale of extrinsic motivation. ----- CONCLUSIONS: Members of the medical faculty differ in motivational orientation for research depending on their academic status, and their motivation is associated more with requirements for academic advancement than with research. These findings have important implications for developing strategies for enhancing academic research production
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