37,869 research outputs found

    Sustainable business models: integrating employees, customers and technology

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    This Special Issue of the Journal of Business & Industrial Marketing has the same title as the 23rd International Conference CBIM 2018 (June 18-20, 2018, Madrid, Spain) “Sustainable Business Models: Integrating Employees, Customers and Technology”. In this edition of International Conference, following a competitive blind review process, papers from 126 authors and 25 countries were ultimately accepted. The best papers of the Conference were invited to submit to this Special Issue and we were also open to direct submissions from other authors. We present here the 17 accepted papers for publication in this Special Issue

    The Critical Point of Unoriented Random Surfaces with a Non-Even Potential

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    The discrete model of the real symmetric one-matrix ensemble is analyzed with a cubic interaction. The partition function is found to satisfy a recursion relation that solves the model. The double-scaling limit of the recursion relation leads to a Miura transformation relating the contributions to the free energy coming from oriented and unoriented random surfaces. This transformation is the same kind as found with a cuartic interaction.Comment: 20p (Frontpage included

    Resolved Hubble Space spectroscopy of ultracool binary systems

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    Using the low-resolution mode of the Space Telescope Imaging Spectrograph (STIS) aboard the \emph{Hubble Space Telescope} (HST), we have obtained spatially resolved spectra of 20 ultracool dwarfs. 18 of them belong to 9 known very low-mass binary systems with angular separations in the range 0.37-0.098 arcseconds. We have derived spectral types in the range dM7.5 to dL6 from the PC3 index, and by comparing our STIS spectra with ground-based spectra of similar spectral resolution from Mart{\'\i}n et al. (1999). We have searched for Hα_\alpha emission in each object but it was clearly detected in only 2 of them. We find that the distribution of Hα_\alpha emission in our sample is statistically different from that of single field dwarfs, suggesting an intriguing anticorrelation between chromospheric activity and binarity for M7--M9.5 dwarfs. We provide measuments of the strength of the main photospheric features and the PC3 index, and we derive calibrations of spectral subclasses versus F814W and K-band absolute magnitudes for a subset of 10 dwarfs in 5 binaries that have known trigonometric parallaxes.Comment: accepted for publication in A&

    Hokupa'a-Gemini Discovery of Two Ultracool Companions to the Young Star HD 130948

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    We report the discovery of two faint ultracool companions to the nearby (d~17.9 pc) young G2V star HD 130948 (HR 5534, HIP 72567) using the Hokupa'a adaptive optics instrument mounted on the Gemini North 8-meter telescope. Both objects have the same common proper motion as the primary star as seen over a 7 month baseline and have near-IR photometric colors that are consistent with an early-L classification. Near-IR spectra taken with the NIRSPEC AO instrument on the Keck II telescope reveal K I lines, FeH, and water bandheads. Based on these spectra, we determine that both objects have spectral type dL2 with an uncertainty of 2 spectral subclasses. The position of the new companions on the H-R diagram in comparison with theoretical models is consistent with the young age of the primary star (<0.8 Gyr) estimated on the basis of X-ray activity, lithium abundance and fast rotation. HD 130948 B and C likely constitute a pair of young contracting brown dwarfs with an orbital period of about 10 years, and will yield dynamical masses for L dwarfs in the near future.Comment: 10 pages, 3 figures, (13 total pages

    The space-time symmetry group of a spin 1/2 elementary particle

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    The space-time symmetry group of a model of a relativistic spin 1/2 elementary particle, which satisfies Dirac's equation when quantized, is analyzed. It is shown that this group, larger than the Poincare group, also contains space-time dilations and local rotations. It has two Casimir operators, one is the spin and the other is the spin projection on the body frame. Its similarities with the standard model are discussed. If we consider this last spin observable as describing isospin, then, this Dirac particle represents a massive system of spin 1/2 and isospin 1/2. There are two possible irreducible representations of this kind of particles, a colourless or a coloured one, where the colour observable is also another spin contribution related to the zitterbewegung. It is the spin, with its twofold structure, the only intrinsic property of this Dirac elementary particle.Comment: Contribution to the JINR(Dubna) SPIN05 workshop, 18 pages, 1 figure. Abstract and minor changes of sections 2 to

    -THE RESPONSE OF EXPENDITURES TO ANTICIPATED INCOME CHANGES: PANEL DATA ESTIMATES

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    Standard models of intertemporal allocation predict that the time path of expenditures should beindependent of the time path of income. Recently two papers, Parker (1999) and Souleles (1999)have suggested that U.S. households have a high marginal propensity to spend within yearanticipated income changes. We use an expenditure survey panel from Spain to re-examine thisissue. We exploit two important features of the Spanish data. First, we have quarterly panel datathat follows households for more than four quarters. Second, we use the fact that workers areexogenously sorted into one of two payment schemes: some receive the same amount eachmonth of the year and others receive an extra payment in June and December. The extra paymentis large and predictable. We examine the detailed pattern of expenditures over the year to seewhether they differ between the two groups. We fail to find even weak differences. Wecomplement this with a conventional Euler equation analysis of excess sensitivity. Our predictingequation for (quarterly) earnings growth is much better than usual and is likely to give a powerfultest of the hypothesis that predictable changes in income do not lead to changes in expenditurepatterns. The results of this analysis confirm the graphical analysis: we find no evidence ofexcess sensitivity. We conclude that households in normal times do smooth consumption overthe year. We suggest a reconciliation of our results with those of Parker and Souleles.Consumption; Excess Sensitivity; Smoothing.

    HABITS AND HETEROGENEITY IN DEMANDS: A PANEL DATA ANALYSIS

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    We examine demand behaviour for intertemporal dependencies, using Spanishpanel data. We present evidence that there is both state dependence and correlatedheterogeneity in demand behaviour. Our specific findings are that food outside thehome, alcohol and tobacco are habit forming whereas clothing and small durablesexhibit durability. We conclude that demand analyses using cross-section data thatignore these effects may be seriously biased. On the other hand, the degree ofintertemporal dependence is not sufficiently strong to make composite `consumption'significantly habit forming, as has been suggested in some recent analyses.Habits, State dependence, correlated heterogeneity.
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