21,039 research outputs found

    Performance of two branch space and polarization diversity at 900 MHz

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    This work summarizes the results of a measurement campaign undertaken to evaluate the performance of two branch space and polarization diversity schemes at 900 MHz in different environments (urban, suburban, rural flat and rural hilly). A total number of 783 runs were made covering these sites and using different transmitter antennas (vertical polarized roof-top antenna, handheld randomly inclined) at differents speeds (walking, by car at 30 up to 80 km/h). Comparison between the two types of diversity schemes have been made through calculation of the statistics of mean received signal level, diversity gain, incremental diversity gain and envelope cross-correlationPeer ReviewedPostprint (published version

    Faint emission lines in the Galactic H II regions M16, M20 and NGC 3603

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    We present deep echelle spectrophotometry of the Galactic {\hii} regions M16, M20 and NGC 3603. The data have been taken with the Very Large Telescope Ultraviolet-Visual Echelle Spectrograph in the 3100 to 10400 \AA range. We have detected more than 200 emission lines in each region. Physical conditions have been derived using different continuum and line intensity ratios. We have derived He+^{+}, C++^{++} and O++^{++} abundances from pure recombination lines as well as abundances from collisionally excited lines for a large number of ions of different elements. We have obtained consistent estimations of the temperature fluctuation parameter, {\ts}, using different methods. We also report the detection of deuterium Balmer lines up to Dδ\delta (M16) and to Dγ\gamma (M20) in the blue wings of the hydrogen lines, which excitation mechanism seems to be continuum fluorescence. The temperature fluctuations paradigm agree with the results obtained from optical CELs and the more uncertain ones from far IR fine structure CELs in NGC 3603, although, more observations covering the same volume of the nebula are necessary to obtain solid conclusions.Comment: 22 pages, 13 Tables, 7 Figures. Accepted for publication by MNRA

    Model-independent sensibility studies for the anomalous dipole moments of the ντ\nu_\tau at the CLIC based γe\gamma e^- colliders

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    To improve the theoretical prediction of the anomalous dipole moments of the τ\tau-neutrino, we have carried out a study through the process γeτνˉτνe\gamma e^- \to \tau \bar\nu_\tau \nu_e, which represents an excellent and useful option in determination of these anomalous parameters. To study the potential of the process γeτνˉτνe\gamma e^- \to \tau \bar\nu_\tau \nu_e, we apply a future high-energy and high-luminosity linear electron-positron collider, such as the CLIC, with s=380,1500,3000GeV\sqrt{s}=380, 1500, 3000\hspace{0.8mm}GeV and L=10,50,100,200,500,1000,1500,2000,3000fb1{\cal L}=10, 50, 100, 200, 500, 1000, 1500, 2000, 3000\hspace{0.8mm}fb^{-1}, and we consider systematic uncertainties of δsys=0,5,10%\delta_{sys}=0, 5, 10\%. With these elements, we present a comprehensive and detailed sensitivity study on the total cross-section of the process γeτνˉτνe\gamma e^- \to \tau \bar\nu_\tau \nu_e, as well as on the dipole moments μντ\mu_{\nu_\tau} and dντd_{\nu_\tau} at the 95%95\% C.L., showing the feasibility of such process at the CLIC at the γe\gamma e^- mode with unpolarized and polarized electron beams.Comment: 28 pages, 15 figure

    The moderating role of gender on entrepreneurial intentions: a TPB perspective

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    Purpose: To disentangle the ways in which social norms shape entrepreneurial intentions of university students and to analyse the moderating effect of gender that may arise. Design/methodology/approach: We have used the entrepreneurial intention model based on Theory of Planned Behaviour (TPB) literature and moderated by students’ gender affecting this intention. We tested some hypotheses using data from undergraduate business students in Spain and their entrepreneurial intentions. Findings: Our results suggest that perceived behavioural control and attitudes affect the entrepreneurial intentions of university students towards entrepreneurship while subjective norms do not. Furthermore, our findings reveal that the moderating effect of gender has a positive influence for women in the relationship between those subjective norms and the perceived behavioural control. However, as to some research done so far, the moderating role of gender does not seem to have a particular effect on predicting entrepreneurial intentions when moderating TPB dimensions. Practical implications: Given the socio-economic benefits attributed to entrepreneurship, the results allow the design of more effective education initiatives and policies. Originality/value: This research provides support for the application of the TPB, allowing for a better understanding of gender differences in entrepreneurial intentions
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