181 research outputs found

    How to manage and minimize food waste in the hotel industry? An exploratory research

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    Purpose – The hospitality industry is responsible for significant amounts of waste, more than one-third of which is food waste. Through the comparison between an Italian and a Romanian hotel, this paper aims to provide a better understanding of food waste management trends in the hotel industry as well as to highlight hotel kitchens and hotel food services weaknesses and opportunities to minimize food waste. Design/methodology/approach – In-depth interviews, personal communication and observations were conducted to investigate food service planning, food procurement and food waste management, as well as to better comprehend current individuals’ understanding and attitudes, infrastructures, legislative culture and opportunities either from the managerial and the employees’ perspective. Data were analyzed according to a content analysis approach. Findings – Three critical hot spots emerged from the analysis: prediction and check of guests’ attendance, communication and transparency with local suppliers and among departments within the unit and purchasing frequency and perishable food provisioning. The accurate forecasting of the number of guests and their nationality is fundamental in avoiding food waste at food service, as well as implementing transparency and communication with local suppliers. Originality/value – Although academia and authorities have recognized the crucial importance of food waste management, food waste research in the hotel industry remains under-researched. The present exploratory research contributes to the scarce empirical studies about hotels’ food waste, giving theoretical and managerial recommendations for supporting further studies, highlighting the need for formal deals between hotels and local suppliers (food procurement), as well as the importance of foodnetworks that holds together companies, retailers and charities (food donation)

    Explaining potentially unfair clauses to the consumer with the claudette tool

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    This paper presents the latest developments of the use of memory network models in detecting and explaining unfair terms in online consumer contracts. We extend the CLAUDETTE tool for the detection of potentially unfair clauses in online Terms of Service, by providing to the users the explanations of unfairness (legal rationales) for five different categories: Arbitration, unilateral change, content removal, unilateral termination, and limitation of liability

    Multiple stellar populations in Magellanic Cloud clusters. V. The split main sequence of the young cluster NGC1866

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    One of the most unexpected results in the field of stellar populations of the last few years, is the discovery that some Magellanic-Cloud globular clusters younger than ~400 Myr, exhibit bimodal main sequences (MSs) in their color-magnitude diagrams (CMDs). Moreover, these young clusters host an extended main sequence turn off (eMSTO) in close analogy with what is observed in most ~1-2 Gyr old clusters of both Magellanic Clouds. We use high-precision Hubble-Space-Telescope photometry to study the young star cluster NGC1866 in the Large Magellanic Cloud. We discover an eMSTO and a split MS. The analysis of the CMD reveals that (i) the blue MS is the less populous one, hosting about one-third of the total number of MS stars; (ii) red-MS stars are more centrally concentrated than blue-MS stars; (iii) the fraction of blue-MS stars with respect to the total number of MS stars drops by a factor of ~2 in the upper MS with F814W <~19.7. The comparison between the observed CMDs and stellar models reveals that the observations are consistent with ~200 Myr old highly-rotating stars on the red-MS, with rotation close to critical value, plus a non-rotating stellar population spanning an age interval between ~140 and 220 Myr, on the blue-MS. Noticeable, neither stellar populations with different ages only, nor coeval stellar models with different rotation rates, properly reproduce the observed split MS and eMSTO. We discuss these results in the context of the eMSTO and multiple MS phenomenon.Comment: 11 pages, 11 figures, accepted for publication in MNRA

    The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. XIX. A Chemical Tagging of the Multiple Stellar Populations Over the Chromosome Maps

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    The HST UV Survey of Globular Clusters (GCs) has investigated GCs and their stellar populations. In previous papers of this series we have introduced a pseudo two-color diagram, "chromosome map" (ChM), that maximises the separation between the multiple populations. We have identified two main classes of GCs: Type I (~83% of the objects) and Type II, both hosting two main groups of stars, referred to in this series as first (1G) and second generation (2G). Type II clusters exhibit two or more parallel sequences of 1G and 2G stars in their ChMs. We exploit elemental abundances from literature to assign the chemical composition to the distinct populations as identified on the ChMs of 29 GCs. We find that stars in different regions of the ChM have different composition: 1G stars share the same light-element content as field stars, while 2G stars are enhanced in N, Na and depleted in O. Stars enhanced in Al and depleted in Mg populate the extreme regions of the ChM. We investigate the color spread among 1G stars observed in many GCs, and find no evidence for variations in light elements, whereas either a 0.1 dex Fe spread or a variation in He remain to be verified. In the attempt of analysing the global properties of the multiple populations, we have constructed a universal ChM, which highlights that, though variegate, the phenomenon has some common pattern. The universal ChM reveals a tight connection with Na, for which we have provided an empirical relation. The additional ChM sequences typical of Type II GCs are enhanced in metallicity and, often, in s elements. Omega Cen can be classified as an extreme Type II GC, with a ChM displaying three main streams, each with its own variations in chemical abundances. One of the most noticeable differences is between the lower and upper streams, with the latter (associated with higher He) having higher Fe and lower Li. We publicly release ChMs.Comment: 35 pages, 28 figures, 3 tables. Submitted to MNRA

    On the kinematic separation of field and cluster stars across the Bulge globular NGC 6528

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    We present deep and precise multi-band photometry of the Galactic Bulge globular cluster NGC6528. The current dataset includes optical and near-infrared images collected with ACS/WFC, WFC3/UVIS, and WFC3/IR on board the Hubble Space Telescope. The images cover a time interval of almost ten years and we have been able to carry out a proper-motion separation between cluster and field stars. We performed a detailed comparison in the m_F814W, m_F606W - m_F814W Color-Magnitude Diagram with two empirical calibrators observed in the same bands. We found that NGC6528 is coeval with and more metal-rich than 47Tuc. Moreover, it appears older and more metal-poor than the super-metal-rich open cluster NGC6791. The current evidence is supported by several diagnostics (red horizontal branch, red giant branch bump, shape of the sub-giant branch, slope of the main sequence) that are minimally affected by uncertainties in reddening and distance. We fit the optical observations with theoretical isochrones based on a scaled-solar chemical mixture and found an age of 11 +- 1 Gyr and an iron abundance slightly above solar ([Fe/H = +0.20). The iron abundance and the old cluster age further support the recent spectroscopic findings suggesting a rapid chemical enrichment of the Galactic Bulge.Comment: 14 pages, 12 figures (2 at low resolution); added references; corrected figure 3, 4, 5, 8 and 9; results unchanged. Erratum to be published in Ap

    The temperature distribution of horizontal branch stars: methods and first results

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    As part of a large project aimed at characterizing the ultraviolet (UV) properties of globular clusters, we present here a theoretical and observational analysis aimed at setting the framework for the determination of horizontal branch (HB) temperature distributions. Indeed this is a crucial information to understand the physical parameters shaping the HB morphology in globular clusters and to interpret the UV emission from unresolved stellar systems. We found that the use of zero age HB color-Teff relations is a robust way to derive effective temperatures of individual HB stars. We investigated the most suitable colors for temperature estimates, and the effect on the color-Teff relations of variations of the initial chemical composition, and of the evolution off the zero age horizontal branch. As a test case, we applied our color-Teff calibrations to the Galactic globular cluster M15. The photometry of M15 has been obtained with the Wide Field and Planetary Camera 2 on board the HST. The HB of M15 turned out to have a multimodal distribution, with a main component peaked at Teff~8,000 K and confined below Teff~10,000 K. The second component is peaked at Teff~14,000 K and extends up to Teff~20,000 K. The vast majority (~95%) of the HB stars in M15 is below 20,000 K, in agreement with the lack of a well populated extreme HB observed in other metal-poor globular clusters. We also verified that the temperatures derived with our analysis are consistent with spectroscopic estimates available in the literature.Comment: 13 pages, 13 figures. ApJ accepte

    The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. XVI. The helium abundance of multiple populations

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    Recent work, based on data from the Hubble Space Telescope (HST) UV Legacy Survey of Galactic Globular Clusters (GCs), has revealed that all the analyzed clusters host two groups of first- (1G) and second-generation (2G) stars. In most GCs, both 1G and 2G stars host sub-stellar populations with different chemical composition. We compare multi-wavelength HST photometry with synthetic spectra to determine for the first time the average helium difference between the 2G and 1G stars in a large sample of 57 GCs and the maximum helium variation within each of them. We find that in all clusters 2G stars are consistent with being enhanced in helium with respect to 1G. The maximum helium variation ranges from less than 0.01 to more than 0.10 in helium mass fraction and correlates with both the cluster mass and the color extension of the horizontal branch (HB). These findings demonstrate that the internal helium variation is one of the main (second) parameters governing the HB morphology.Comment: 26 pages, 19 figures, accepted for publications in MNRA

    WFPC2 UV survey of Galactic globular clusters. The Horizontal Branch temperature distribution

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    Ultraviolet observations are the best tool to study hot stellar populations which emit most of their light at short wavelengths. As part of a large project devoted to the characterization of the UV properties of Galactic globular clusters (GGCs), we collected mid/far UV and optical images with the WFPC2@HST for 31 GGCs. These clusters cover a wide range in metallicity and structural parameters, thus representing an ideal sample for comparison with theoretical models. Here we present the first results from an ongoing analysis aimed at deriving the temperature distribution of Horizontal Branch stars in GGCs
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