20,712 research outputs found

    Herding behaviour in a peripheral European stock market: the impact of the subprime and the European sovereign debt crises

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    The characteristics of the Portuguese stock market suggest that it is susceptible to herding behaviour. We investigate the existence of this behaviour in Portugal during periods of market stress, with emphasis on the subprime and European sovereign debt crises. We analyse the overall stock market, key industries, and portfolios divided by market capitalisation. The study is performed using both linear and nonlinear models, and the impact of conditional variance is taken into account. This paper shows evidence of herding behaviour when the nonlinear model is used and during periods of crisis. Investors imitate more assets of similar size than assets of the same industry. Finally, the evidence of herding behaviour is reduced when GARCH effects are taken into account

    Pain Medicine Fellowship Program Websites in the United States of America - A Nonparametric Statistic Analysis of 14 Different Criteria

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    Objective: To evaluate the content of Pain Medicine Fellowship Program websites in the United States of America. Methods: We obtained a list of accredited 104 Pain Medicine Fellowship Program websites from the Accreditation Council for Graduate Medical Education and the Electronic Residency Application Service. Individual Pain Medicine Fellowship Program websites were then evaluated on 14 different criteria. We grouped fellowship programs based on census region and Electronic Residency Application Service participation status, and analyzed the differences using nonparametric statistics. Results: A total of 104 accredited Pain Medicine Fellowship Program websites were evaluated for a total of 14 different criteria. Of the 14 different criteria, an average of 3.94 were described in each website. Number of Fellowship positions per year (71.8%), clinical rotations during the program (65.1%), and faculty background (62.2%) were the most frequently described features on the websites. Night call responsibilities (3.9%), meal allowance (7.8%) and parking availability (10.7%) were the least described features in the websites. There were no significant differences between program websites when grouped by census regions or the participation status in the Electronic Residency Applications Service. Conclusion: The content of Pain Medicine Fellowship Program websites is extremely variable across the United States of America. This study indicates that there is room for improvement and enhancement of the comprehensiveness of website content for the majority of the programs analyzed. Additionally, this study also emphasizes the importance of having accurate and easily available online information in a post-pandemic era, when prospective fellows evaluate programs online through their websites.info:eu-repo/semantics/publishedVersio

    M\"obius and twisted graphene nanoribbons: stability, geometry and electronic properties

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    Results of classical force field geometry optimizations for twisted graphene nanoribbons with a number of twists NtN_t varying from 0 to 7 (the case NtN_t=1 corresponds to a half-twist M\"obius nanoribbon) are presented in this work. Their structural stability was investigated using the Brenner reactive force field. The best classical molecular geometries were used as input for semiempirical calculations, from which the electronic properties (energy levels, HOMO, LUMO orbitals) were computed for each structure. CI wavefunctions were also calculated in the complete active space framework taking into account eigenstates from HOMO-4 to LUMO+4, as well as the oscillator strengths corresponding to the first optical transitions in the UV-VIS range. The lowest energy molecules were found less symmetric than initial configurations, and the HOMO-LUMO energy gaps are larger than the value found for the nanographene used to build them due to electronic localization effects created by the twisting. A high number of twists leads to a sharp increase of the HOMO →\to LUMO transition energy. We suggest that some twisted nanoribbons could form crystals stabilized by dipolar interactions

    Evaluation of six nopal (Opuntia spp.) varieties for fodder production in the semi-arid Northeast, Brazil.

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    The main problems associated with production of fodder nopal in the Sertão region, Semi-arid Northeast, Brazil, are poor soils, high minimum temperature (above 20.5o C), and the armored scale insect (Diaspis echinocacti - Bouchè). A field trial was established in Petrolina, State of Pernambuco ( average rainfall 552.2 mm, 80% available from December to April) in April 2000. Six varieties were tested: three local varieties, ?Gigante?, the most cultivated, ?Redonda? (both Opuntia ficus-indica) and ?Doce? (Nopalea cochenillifera); the Clone IPA-20, furnished by IPA, a local research institution; two varieties provided by the Universidad. Autonoma de Chapingo, Mexico, COPENA F1 and COPENA V1. The experimental design was a CRB , with three replications. The plots had 16 m2 (four rows with eight plants/row) planting density was 20.000, plants/ha, for evaluation, only six plants of each central line were considered Manure was applied on biannual basis, at the rate of 2.86 kg/m. Weeding was performed manually. After four years (May 2004), the first harvest was done, collecting all fresh material except the basal cladode and the first layer of pads.. Annual fresh matter (FM) production was calculated dividing total yield by four. Mean production was 65.36 ± 22.99 ton FM/ha/year (CV = 35.17%). Varieties yields were: ?Gigante? nopal, 103.80 ton; ?Redonda? nopal, 78.04 ton; COPENA F1, 77.54 ton; Clone IPA-20, 74.15 ton; COPENA V1, 34.19 ton; ?Doce? nopal, 24.40 ton. ?Gigante? nopal was significantly superior (P<0.05) to the two last varieties, and ?Doce? nopal was inferior to all varieties. Height, longitudinal and transversal canopy diameters were, respectively: ?Gigante? nopal, 1.54, 1.09 and 1.08 m; ?Redonda? nopal, 1.07, 1.07 and 0.98 m; COPENA F1, 1.73, 1.08 and 0.90 m; Clone IPA-20, 1.38, 1.11 and 0.99 m; COPENA V1, 1.28, 0.91, 0.76 m; ?Doce? nopal, 1.06, 1.07, and 0.99 m. Other data that, such as, protein and fiber levels, might indicate that highest production does not assure the best variety for the region. COPENA F1 having shorter canopy diameter, in comparison to ?Gigante? nopal (0.90 vs. 1.08 m) would make it more
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