Worth it? The usefulness of information technology to read ID cards and passports for hoteliers in Bulgaria

Purpose – The case study investigates whether a particular IT is worthwhile, in view of its perceived, potential and actual usefulness. It answers two research questions: How necessary is an automated ID card/passport reader for hoteliers? and Which characteristics of such software do hoteliers most favour? Design – Data collection took place in 2013 through an online questionnaire. The sample includes 70 hotel managers in Bulgaria. Methodology – Kruskal-Wallis χ2 test and Wilcoxon signed ranks test were used in the data analysis. Approach – The case study adopted survey as a research strategy. The sample includes only respondents from Bulgaria. Hence, findings are generalisable only in this cultural setting. Findings – Findings revealed that the most important software characteristics desired by hotel managers are: quality, price, easy to use interface, speed, integration with the existing hotel software and completeness of the extracted data. However, results suggest that there is little necessity of an automated ID card reader due to limited time savings offered by the new technology and few mistakes during the manual entry of ID card/passport data in the information systems of hotels. Originality of the research – This empirical research practically assesses the viability of specific technology adoption by hoteliers in Bulgaria. This research was implemented by the authors in response to a request by a company that produces software for ID card/passport readers. The results helped the company in its product launch and follow-up marketing strategy

The effect of the quasar H1821+643 on the surrounding intracluster medium: revealing the underlying cooling flow

We present a detailed study of the thermodynamic properties of the intracluster medium of the only low redshift galaxy cluster to contain a highly luminous quasar, H1821+643. The cluster is a highly massive, strong cool core cluster. We find that the ICM entropy around the quasar is significantly lower than that of other similarly massive strong cool core clusters within the central 80 kpc, and that the entropy lies significantly below the extrapolated baseline entropy profile from hierarchical structure formation. By comparing the scaled temperature profile with those of other strong cool core clusters of similar total mass, we see that the entropy deficiency is due to the central temperature being significantly lower. This suggests that the presence of the quasar in the core of H1821+643 has had a dramatic cooling effect on the intracluster medium around it. We find that, if the quasar was brighter in the past, Compton cooling by radiation from the quasar may have caused the low entropy and temperature levels in the ICM around the quasar. Curiously, the gradients of the steep central temperature and entropy decline are in reasonable agreement with the profiles expected for a constant pressure cooling flow. It is possible that the system has been locked into a Compton cooled feedback cycle which prevents energy release from the black hole heating the gas sufficiently to switch it off, leading to the formation of a huge (~3x10^10 solar mass) supermassive black hole.Comment: 8 pages, 10 figures. Accepted for publication in MNRA

An excess of damped Lyman alpha galaxies near QSOs

We present a sample of 33 damped Lyman alpha systems (DLAs) discovered in the Sloan Digital Sky Survey (SDSS) whose absorption redshifts (z_abs) are within 6000 km/s of the QSO's systemic redshift (z_sys). Our sample is based on 731 2.5 < z_sys < 4.5 non-broad-absorption-line (non-BAL) QSOs from Data Release 3 (DR3) of the SDSS. We estimate that our search is ~100 % complete for absorbers with N(HI) >= 2e20 cm^-2. The derived number density of DLAs per unit redshift, n(z), within v < 6000 km/s is higher (3.5 sigma significance) by almost a factor of 2 than that of intervening absorbers observed in the SDSS DR3, i.e. there is evidence for an overdensity of galaxies near the QSOs. This provides a physical motivation for excluding DLAs at small velocity separations in surveys of intervening 'field' DLAs. In addition, we find that the overdensity of proximate DLAs is independent of the radio-loudness of the QSO, consistent with the environments of radio-loud and radio-quiet QSOs being similar.Comment: Accepted for publication in MNRAS (13 pages, 6 figures

Petrology and geochemistry of nakhlite MIL 03346: A new Martian meteorite from Antarctica

MIL 03346 is the first nakhlite in the US Antarctic collection. We have performed detailed mineralogical and bulk-geochemical investigations to compare petrogenesis of this Martian meteorite with other nakhlites

p-Wave stabilization of three-dimensional Bose-Fermi solitons

We explore bright soliton solutions of ultracold Bose-Fermi gases, showing that the presence of p-wave interactions can remove the usual collapse instability and support stable soliton solutions that are global energy minima. A variational model that incorporates the relevant s- and p-wave interactions in the system is established analytically and solved numerically to probe the dependencies of the solitons on key experimental parameters. Under attractive s-wave interactions, bright solitons exist only as meta-stable states susceptible to collapse. Remarkably, the presence of repulsive p-wave interactions alleviates this collapse instability. This dramatically widens the range of experimentally-achievable soliton solutions and indicates greatly enhanced robustness. While we focus specifically on the boson-fermion pairing of 87Rb and 40K, the stabilization inferred by repulsive p-wave interactions should apply to the wider remit of ultracold Bose-Fermi mixtures.Comment: 9 pages, 6 figure

Different twins in the millisecond pulsar recycling scenario: optical polarimetry of PSR J1023+0038 and XSS J12270-4859

We present the first optical polarimetric study of the two transitional pulsars PSR J1023+0038 and XSS J12270-4859. This work is focused on the search for intrinsical linear polarisation (LP) in the optical emission from the two systems. We carried out multiband optical and NIR photo-polarimetry of the two systems using the ESO NTT at La Silla (Chile), equipped with the EFOSC2 and the SOFI instruments. XSS J12270-4859 was observed during its radio-pulsar state; we did not detect LP in all bands, with 3 sigma upper limits of, e.g., 1.4% in the R-band. We built the NIR-optical averaged spectral energy distribution (SED) of the system, that could be well described by an irradiated black body with radius $R_{*} = 0.33\pm0.03\,R_{\odot}$ and albedo $\eta=0.32\pm0.05$, without the need of further components (thus excluding the visible presence of an extended accretion disc and/or of relativistic jets). The case was different for PSR J1023+0038, that was in its accretion phase during our campaign. We measured a LP of $1.09\pm0.27\%$ and $0.90\pm 0.17\%$ in the V and R bands, respectively. The phase-resolved polarimetric curve of the source in the R-band reveals a hint of a sinusoidal modulation at the source 4.75 hr orbital period, peaked at the same orbital phase as the light curve. The measured LP of PSR J1023+0038 could in principle be interpreted as scattering with free electrons (that can be found in the accretion disc of the system or even in the hot corona that surrounds the disc itself) or to synchrotron emission from a relativistic particles jet or outflow. However, the NIR-optical SED of the system built starting from our dataset did not suggest the presence of a jet. We conclude that the optical LP observed for PSR J1023+0038 is possibly due to Thomson scattering with electrons in the disc, as also suggested from the possible modulation of the R-band LP at the system orbital period.Comment: 10 pages, 8 figures, 4 tables. Accepted for publication in Sec. 7. Stellar structure and evolution of Astronomy and Astrophysic