1,479 research outputs found

    Fisheries and reproductive biology of Octopus vulgaris (Mollusca: Cephalopoda) in the Gulf of Alicante (Northwestern Mediterranean)

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    The common octopus Octopus vulgarisCuvier, 1797 is the most fished cephalopod species along the Spanish coasts. Its catches are highly fluctuating due to the short life cycle of the species and to the annual variability of the recruitment pattern, strongly dependent on the environmental conditions affecting the eggs and paralarvae. This study examines the common octopus fishery, the catch composition, and the main features of the reproductive biology of this species in the Gulf of Alicante (Spanish Eastern coast, Western Mediterranean FAO division 37.1.1). The common octopus fishery was studied analysing the monthly landing and effort data by fishing gear from 1994 to 2005. Monthly samplings of the commercial O. vulgarislandings from trawlers and clay pots from January 2004 to December 2005 resulted in the measuring of 1833 specimens to enable analysis of the catch composition, and allowed the biological sampling of 1176 individuals to provide the reproductive parameters of the species in the study area. The length-weight relationship calculated for the species was BW = 0.51 * DML 2.87. The yearly sex ratios (males:females) were 1:1 (trawl, 2004), 1:0.74 (trawl, 2005), and 1:0.88 (clay pots, 2005). The size (dorsal mantle length, DML) at maturity of the species in the study area was 9.67 cm for males and 14.38 cm for females. The gonadosomatic index reached a peak between April and July for males and in July for females. The Fulton condition index was lower in both sexes between June and September, and for males in November-December, whereas for both sexes the values of the digestive gland index were at their maximum between June and December. The energy allocation between somatic and reproductive growth was investigated and the results suggested that the energy spent on reproduction mainly came from feeding, and not from energy stored in the mantle tissues or in the digestive glan

    Limits on excited tau leptons masses from leptonic tau decays

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    We study the effects induced by excited leptons on the leptonic tau decay at one loop level. Using a general effective lagrangian approach to describe the couplings of the excited leptons, we compute their contributions to the leptonic decays and use the current experimental values of the branching ratios to put limits on the mass of excited states and the substructure scale.Comment: 10 pages, 6 figures, to be published in Phys. Rev.

    The effect of interpolation methods in temperature and salinity trends in the Western Mediterranean

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    Temperature and salinity data in the historical record are scarce and unevenly distributed in space and time and the estimation of linear trends is sensitive to different factors. In the case of the Western Mediterranean, previous works have studied the sensitivity of these trends to the use of bathythermograph data, the averaging methods or the way in which gaps in time series are dealt with. In this work, a new factor is analysed: the effect of data interpolation. Temperature and salinity time series are generated averaging existing data over certain geographical areas and also by means of interpolation. Linear trends from both types of time series are compared. There are some differences between both estimations for some layers and geographical areas, while in other cases the results are consistent. Those results which do not depend on the use of interpolated or non-interpolated data, neither are influenced by data analysis methods can be considered as robust ones. Those results influenced by the interpolation process or the factors analysed in previous sensitivity tests are not considered as robust results

    The impact of silent vascular brain burden in cognitive impairment in Parkinson's disease

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    White matter hyperintensities (WMHs) detected by magnetic resonance imaging (MRI) of the brain are associated with dementia and cognitive impairment in the general population and in Alzheimer's disease. Their effect in cognitive decline and dementia associated with Parkinson's disease (PD) is still unclear. METHODS: We studied the relationship between WMHs and cognitive state in 111 patients with PD classified as cognitively normal (n = 39), with a mild cognitive impairment (MCI) (n = 46) or dementia (n = 26), in a cross-sectional and follow-up study. Cognitive state was evaluated with a comprehensive neuropsychological battery, and WMHs were identified in FLAIR and T2-weighted MRI. The burden of WMHs was rated using the Scheltens scale. RESULTS: No differences in WMHs were found between the three groups in the cross-sectional study. A negative correlation was observed between semantic fluency and the subscore for WMHs in the frontal lobe. Of the 36 non-demented patients re-evaluated after a mean follow-up of 30 months, three patients converted into MCI and 5 into dementia. Progression of periventricular WMHs was associated with an increased conversion to dementia. A marginal association between the increase in total WMHs burden and worsening in the Mini Mental State Examination was encountered. CONCLUSIONS: White matter hyperintensities do not influence the cognitive status of patients with PD. Frontal WMHs have a negative impact on semantic fluency. Brain vascular burden may have an effect on cognitive impairment in patients with PD as WMHs increase overtime might increase the risk of conversion to dementia. This finding needs further confirmation in larger prospective studies

    A vision about lifelong learning and its barriers

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    Around 25 years ago, some researchers argued for moving towards innovative learning models characterized by being more personalized and where the students would have a more active role in deciding what to learn, when to learn and how to learn. Nowadays, there is a need for a flexible, efficient, universal and lifelong education. Lifelong learning is fully integrated into our society and, from the student point of view, it is very different from regular learning. Among these differences there is the maturity of students, the fact that the domains of interest are much broader, the way how learning occurs at different depths, the fact that the topics to study may be related both to work, family and leisure, and that students have little availability due to their necessity to conciliate home, work, leisure and learning. Lifelong learning requires personalized models that adapt to students'' needs and constraints, but lifelong learners keep suffering from models that are neither adapted to their necessities, nor to the needs of society. This paper reflects on the actual situation of lifelong learning, analyses some of the relevant literature and discusses the challenges to conceptualize, from a transdisciplinary point of view, innovative e-learning models that promote self-determination of students

    What do we evaluate in sport mindfulness interventions? A systematic review of commonly used questionnaires

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    Interest of the study: mindfulness is a concept describing the focus on the present moment, intentionally and without judgement. This approach has only recently been applied to sport psychology. Objectives: the aim of the current review is to investigate which indicators and questionnaires are used in mindfulness research in sport, being specifically interested in mindfulness assessment. Methods: PRISMA guidelines for systematic reviews and the recommendations of the Cochrane Collaboration were used. Literature searches were conducted in Psychinfo, PubMed, EMBASE and the Cochrane Library. Results: From 2, 203 records initially retrieved, 17 articles were included. The results show that mindfulness, anxiety and acceptance are the most commonly studied psychological indicators. The Five Facet Mindfulness Questionnaire is the most frequently used mindfulness scale. We also discuss the possibility of using physiological indicators as complementary assessment. Conclusions: It is recommended to specifically adapt some questionnaires, such is already done with the Sport Anxiety Scale or the Mindfulness Inventory for Sport, for their use in sport psychology

    Excited Fermion Contribution to Z Physics at One Loop

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    We investigate the effects induced by excited leptons at the one-loop level in the observables measured on the ZZ peak at LEP. Using a general effective Lagrangian approach to describe the couplings of the excited leptons, we compute their contributions to both oblique parameters and ZZ partial widths. Our results show that the new effects are comparable to the present experimental sensitivity, but they do not lead to a significant improvement on the available constraints on the couplings and masses of these states.Comment: 25 pages 6 figure

    Neutrino hierarchy from CP-blind observables with high density magnetized detectors

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    High density magnetized detectors are well suited to exploit the outstanding purity and intensities of novel neutrino sources like Neutrino Factories and Beta Beams. They can also provide independent measurements of leptonic mixing parameters through the observation of atmospheric muon-neutrinos. In this paper, we discuss the combination of these observables from a multi-kton iron detector and a high energy Beta Beam; in particular, we demonstrate that even with moderate detector granularities the neutrino mass hierarchy can be determined for Ξ13\theta_{13} values greater than 4∘^\circ.Comment: 16 pages, 7 figures. Added a new section discussing systematic errors (sec 5.2); sec.5.1 and 4 have been extended. Version to appear in EPJ
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