An International Analysis of Differences in Logistics Performance

The ratio Value Added to Inventory Value is used as a proxy for logistic performance. Large differences -- up to 8 times -- have been observed among the 14 nations in the study. The rank among the nations has been rather stable for the last 20 years but the ratio has improved considerably in most countries since 1980. Several hypotheses concerning the factors which explain the differences in inventory levels are formulated based on theories and case studies in the areas of production, trade, transport, communication, geography and social-economy. Proxies for some of these factors available in international statistics are used as independent variables in multiple regression analyses. The preliminary result indicates that as much as 80% of the differences could be explained by differences in import share, rail share, wholesale structure and telephone intensity. Hence, the hypothesis that differences in national inventory levels are only due to managerial factors or level of economic development could be rejected. Even if the logistic performance of individual companies can be improved considerably by adopting new management principles -- as many case studies show -- the total logistic performance of a nation seems to have significantly benefited from investments in transportation, production and communication infrastructures. However, it has still to be shown that these historical correlations are also causal relations that hold true for the future

Photometric and spectroscopic variability of the FUor star V582 Aurigae

We carried out BVRI CCD photometric observations in the field of V582 Aur from 2009 August to 2013 February. We acquired high-, medium-, and low-resolution spectroscopy of V582 Aur during this period. To study the pre-outburst variability of the target and construct its historical light curve, we searched for archival observations in photographic plate collections. Both CCD and photographic observations were analyzed using a sequence of 14 stars in the field of V582 Aur calibrated in BVRI. The pre-outburst photographic observations of V582 Aur show low-amplitude light variations typical of T Tauri stars. Archival photographic observations indicate that the increase in brightness began in late 1984 or early 1985 and the star reached the maximum level of brightness at 1986 January. The spectral type of V582 Aur can be defined as G0I with strong P Cyg profiles of H alpha and Na I D lines, which are typical of FU Orionis objects. Our BVRI photometric observations show large amplitude variations V~2.8 mag. during the 3.5 year period of observations. Most of the time, however, the star remains in a state close to the maximum brightness. The deepest drop in brightness was observed in the spring of 2012, when the brightness of the star fell to a level close to the pre-outburst. The multicolor photometric data show a color reversal during the minimum in brightness, which is typical of UX Ori variables. The corresponding spectral observations show strong variability in the profiles and intensities of the spectral lines (especially H alpha), which indicate significant changes in the accretion rate. On the basis of photometric monitoring performed over the past three years, the spectral properties of the maximal light, and the shape of the long-term light curve, we confirm the affiliation of V582 Aur to the group of FU Orionis objects.Comment: 9 pages, 8 figures, accepted for publication in A&

Multi-site, multi-year monitoring of the oscillating Algol-type eclipsing binary CT Her

We present the results of a multi-site photometric campaign carried out in 2004-2008 for the Algol-type eclipsing binary system CT Her, the primary component of which shows Delta Scuti-type oscillations. Our data consist of differential light curves collected in the filters B and V which have been analysed using the method of Wilson-Devinney (PHOEBE). After identification of an adequate binary model and removal of the best-matching light curve solution, we performed a Fourier analysis of the residual B and V light curves to investigate the pulsational behaviour. We confirm the presence of rapid pulsations with a main period of 27.2 min. Up to eight significant frequencies with semi-amplitudes in the range 3 to 1 mmag were detected, all of which surprisingly lie in the frequency range 43.5-53.5 c\d. This result is independent from the choice of the primary's effective temperature (8200 or 8700 K) since the light curve models for the binary are very similar in both cases. This is yet another case of a complex frequency spectrum observed for an accreting Delta Scuti-type star (after Y Cam). In addition, we demonstrate that the amplitudes of several of these pulsation frequencies show evidence of variability on time scales as short as 1-2 years, perhaps even less. Moreover, our analysis takes into account some recently acquired spectra, from which we obtained the corresponding radial velocities for the years 2007-2009. Investigation of the O-C diagram shows that further monitoring of the epochs of eclipse minima of CT Her will cast a new light on the evolution of its orbital period.Comment: 13 pages, 13 encapsulated Postscript figures. Tables~3, 4, 9 and 12 will be available in electronic form only. Astronomy and Astrophysics, in process (2011). Replaced the abstract with its final versio