21,673 research outputs found

    A content and comparative analysis of strategic management research in the Baltic area

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    Purpose – The purpose of this paper is to provide a research agenda for qualitative studies in the field of strategic management (SM) in the Baltic area. Design/methodology/approach – A total of 167 SM-related articles in this area between 2000 and 2013 were found. The content within title, abstract and authors’ keywords was analysed by means of a multiple correspondence analysis based on the HOMALS technique. Findings – The intellectual structure of SM in the Baltic area is to some extent similar to the global structure of the field. Hence research on this topic in the Baltic area is well integrated in the field. Three topics of interest have been identified while the fourth seems to offer more limited opportunities for qualitative studies. These are: entry and competition; strategic behaviour and the micro-foundations of strategy; the growth-performance relationship; and global strategies. Research limitations/implications – Despite the modest number of articles in our sample, the findings are consistent with past research on the structure of the SM field. The classification of articles into qualitative- and quantitative-based methods helped provide a research agenda. Practical implications – SM scholars in the Baltic area may find this paper as an interesting input to their quest for finding and justifying their own research path. Originality/value – This is an original literature review. The use of a quantitative method in the literature review and the suggested matrix is a second original contribution to evolving methodologies for content analysis. The method allows the inclusion of large samples while limiting the use of scholars’ intuition. </jats:sec

    Impact of Electric Fields on Highly Excited Rovibrational States of Polar Dimers

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    We study the effect of a strong static homogeneous electric field on the highly excited rovibrational levels of the LiCs dimer in its electronic ground state. Our full rovibrational investigation of the system includes the interaction with the field due to the permanent electric dipole moment and the polarizability of the molecule. We explore the evolution of the states next to the dissociation threshold as the field strength is increased. The rotational and vibrational dynamics are influenced by the field; effects such as orientation, angular motion hybridization and squeezing of the vibrational motion are demonstrated and analyzed. The field also induces avoided crossings causing a strong mixing of the electrically dressed rovibrational states. Importantly, we show how some of these highly excited levels can be shifted to the continuum as the field strength is increased, and reversely how two atoms in the continuum can be brought into a bound state by lowering the electric field strength.Comment: 10 pages, 4 figure

    X-ray spectral variability of seven LINER nuclei with XMM-Newton and Chandra data

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    One of the most important features in active galactic nuclei (AGN) is the variability of their emission. Variability has been discovered at X-ray, UV, and radio frequencies on time scales from hours to years. Among the AGN family and according to theoretical studies, Low-Ionization Nuclear Emission Line Region (LINER) nuclei would be variable objects on long time scales. Our purpose is to investigate spectral X-ray variability in LINERs and to understand the nature of these kinds of objects, as well as their accretion mechanism. Chandra and XMM-Newton public archives were used to compile X-ray spectra of seven LINER nuclei at different epochs with time scales of years. To search for variability we fit all the spectra from the same object with a set of models, in order to identify the parameters responsible for the variability pattern. We also analyzed the light curves in order to search for short time scale (from hours to days) variability. Whenever possible, UV variability was also studied. We found spectral variability in four objects, with variations mostly related to hard energies (2-10 keV). These variations are due to changes in the soft excess, and/or changes in the absorber, and/or intrinsic variations of the source. Another two galaxies seem not to vary. Short time scale variations during individual observations were not found. Our analysis confirms the previously reported anticorrelation between the X-ray spectral index and the Eddington ratio, and also the correlation between the X-ray to UV flux ratio and the Eddington ratio. These results support an Advection Dominated Accretion Flow (ADAF) as the accretion mechanism in LINERs.Comment: 35 pages, 53 figures, recently accepted pape

    X-ray spectral variability of Seyfert 2 galaxies

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    Variability across the electromagnetic spectrum is a property of AGN that can help constraining the physical properties of these galaxies. This is the third of a serie of papers with the aim of studying the X-ray variability of different families of AGN. The main purpose of this work is to investigate the variability pattern in a sample of optically selected type 2 Seyfert galaxies. We use the 26 Seyferts in the Veron-Cetty and Veron catalogue with data available from Chandra and/or XMM-Newton public archives at different epochs, with timescales ranging from a few hours to years. All the spectra of the same source are simultaneously fitted and we let different parameters to vary in the model. Whenever possible, short-term variations and/or long-term UV flux variations are studied. We divide the sample in Compton-thick, Compton-thin, and changing-look candidates. Short-term variability at X-rays is not found. From the 25 analyzed sources, 11 show long-term variations; eight (out of 11) are Compton-thin, one (out of 12) is Compton-thick, and the two changing-look candidates are also variable. The main driver for the X-ray changes is related to the nuclear power (nine cases), while variations at soft energies or related with absorbers at hard X-rays are less common, and in many cases these variations are accompained with variations of the nuclear continuum. At UV frequencies nuclear variations are nor found. We report for the first time two changing-look candidates, MARK273 and NGC7319. A constant reflection component located far away from the nucleus plus a variable nuclear continuum are able to explain most of our results; the Compton-thick candidates are dominated by reflection, which supresses their continuum making them seem fainter, and not showing variations, while the Compton-thin and changing-look candidates show variations.Comment: Accepted for publication in A&
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