Argon assisted chemical vapor deposition of CrO2_2: an efficient process leading to high quality epitaxial films

A comparative study of the structural, microstructural and magnetic properties of CrO$_2$ thin films grown onto (110) and (100) TiO$_2$ rutile single crystal substrates by chemical vapor deposition (CVD), using CrO$_3$ as chromium precursor and either oxygen or argon as carrier gas is presented. Our results show that growth under argon carrier gas leads to high quality CrO$_2$ epilayers with structural and magnetic properties similar to those obtained using the more standard oxygen carrier gas. Furthermore, we interpret the larger magnetic coercivity observed for the (110) oriented films in terms of their microstructure, in particular of the highest strain and edge roughness of the building structures of the CrO$_2$ epilayers, which are settled by the substrate crystallographic orientation.Comment: 27 pages, 2 tables, 8 figure

Competition in tourism arrivals: a multidimensional index of geographical structural similarity

Given the economic importance of the tourism sector, countries actively compete for attracting tourism flows. In a bilateral perspective, an important determinant of the degree of competition is the geographical structure of tourism inflows (i.e., the relative importance of the different source countries). A higher overlap of these flows indicates greater competition. The present study proposes a methodological approach to quantify this overlap. Taking some indicators traditionally used in international trade analysis as inspiration, we propose a methodology that measures, for each pair of countries, the degree of similarity between the geographical structures of tourism inflows. The methodology takes a multidimensional concept of structural similarity in order to incorporate relevant dimensions of international tourism flows todayinfo:eu-repo/semantics/publishedVersio

HeriTeller 3D, a New Persistent Virtual-World Platform for Cultural Heritage Interpretation and Dissemination

Identificação e avaliação crítica de alguns dos mais recentes instrumentos de disseminação e interpretação do Património Cultural, no universo contemporâneo das plataformas virtuais

Tightening the belt: Constraining the mass and evolution in SDC335

Recent ALMA observations identified one of the most massive star-forming cores yet observed in the Milky Way; SDC335-MM1, within the infrared dark cloud SDC335.579-0.292. Along with an accompanying core MM2, SDC335 appears to be in the early stages of its star formation process. In this paper we aim to constrain the properties of the stars forming within these two massive millimetre sources. Observations of SDC335 at 6, 8, 23 and 25GHz were made with the ATCA. We report the results of these continuum measurements, which combined with archival data, allow us to build and analyse the spectral energy distributions (SEDs) of the compact sources in SDC335. Three HCHII regions within SDC335 are identified, two within the MM1 core. For each HCHII region, a free-free emission curve is fit to the data allowing the derivation of the sources' emission measure, ionising photon flux and electron density. Using these physical properties we assign each HCHII region a ZAMS spectral type, finding two protostars with characteristics of spectral type B1.5 and one with a lower limit of B1-B1.5. Ancillary data from infrared to mm wavelength are used to construct free-free component subtracted SEDs for the mm-cores, allowing calculation of the bolometric luminosities and revision of the previous gas mass estimates. The measured luminosities for the two mm-cores are lower than expected from accreting sources displaying characteristics of the ZAMS spectral type assigned to them. The protostars are still actively accreting, suggesting that a mechanism is limiting the accretion luminosity, we present the case for two different mechanisms capable of causing this. Finally, using the ZAMS mass values as lower limit constraints, a final stellar population for SDC335 was synthesised finding SDC335 is likely to be in the process of forming a stellar cluster comparable to the Trapezium Cluster and NGC6334 I(N).Comment: 10 pages, 5 figures. Accepted for publication in A&

Analytic quasi-steady evolution of a marginally unstable wave in the presence of drag and scattering

The 1D bump-on-tail problem is studied in order to determine the influence of drag on quasi-steady solutions near marginal stability ($1-\gamma_d/\gamma_L\ll 1$) when effective collisions are much larger than the instability growth rate ($\nu \gg \gamma$). In this common tokamak regime, it is rigorously shown that the paradigmatic Berk-Breizman cubic equation for the nonlinear mode evolution reduces to a much simpler differential equation, dubbed the time-local cubic equation, which can be solved directly. It is found that in addition to increasing the saturation amplitude, drag introduces a shift in the apparent oscillation frequency by modulating the saturated wave envelope. Excellent agreement is found between the analytic solution for the mode evolution and both the numerically integrated Berk-Breizman cubic equation and fully nonlinear 1D Vlasov simulations. Experimentally isolating the contribution of drag to the saturated mode amplitude for verification purposes is explored but complicated by the reality that the amount of drag can not be varied independently of other key parameters in realistic scenarios. While the effect of drag is modest when the ratio of drag to scattering $\alpha/\nu$ is very small, it can become substantial when $\alpha/\nu \gtrsim 0.5$, suggesting that drag should be accounted for in quantitative models of fast-ion-driven instabilities in fusion plasmas.Comment: 22 pages, 11 figure

Multiscale Partition of Unity

We introduce a new Partition of Unity Method for the numerical homogenization of elliptic partial differential equations with arbitrarily rough coefficients. We do not restrict to a particular ansatz space or the existence of a finite element mesh. The method modifies a given partition of unity such that optimal convergence is achieved independent of oscillation or discontinuities of the diffusion coefficient. The modification is based on an orthogonal decomposition of the solution space while preserving the partition of unity property. This precomputation involves the solution of independent problems on local subdomains of selectable size. We deduce quantitative error estimates for the method that account for the chosen amount of localization. Numerical experiments illustrate the high approximation properties even for 'cheap' parameter choices.Comment: Proceedings for Seventh International Workshop on Meshfree Methods for Partial Differential Equations, 18 pages, 3 figure

A unification in the theory of linearization of second order nonlinear ordinary differential equations

In this letter, we introduce a new generalized linearizing transformation (GLT) for second order nonlinear ordinary differential equations (SNODEs). The well known invertible point (IPT) and non-point transformations (NPT) can be derived as sub-cases of the GLT. A wider class of nonlinear ODEs that cannot be linearized through NPT and IPT can be linearized by this GLT. We also illustrate how to construct GLTs and to identify the form of the linearizable equations and propose a procedure to derive the general solution from this GLT for the SNODEs. We demonstrate the theory with two examples which are of contemporary interest.Comment: 8 page

Authentic leadership’s effect on customer orientation and turnover intention among Portuguese hospitality employees: the mediating role of affective commitment

Purpose: Hospitality employees’ attitudes and behaviors play a crucial role in enhancing customer satisfaction and service quality and ultimately firms’ success; therefore, organizations must have skilled, customer-oriented staff. More research is required to help hospitality managers gain insights into the best strategies to promote and retain customer-oriented employees. This study specifically sought to provide a more comprehensive understanding of the ways that authentic leadership (AL) can affect employees’ customer orientation and turnover intention, including exploring affective commitment’s (AC) potential mediating role. Design/methodology/approach: The sample included 350 employees from different hospitality organizations in Portugal. Data were collected using anonymously completed structured questionnaires available online or in a paper-and-pencil format. Findings: The results demonstrate that AL has a positive effect on customer orientation and a negative effect on turnover intention. Moreover, they indicate that AC mediates the relationships between AL and both customer orientation and turnover intention. All hypotheses received empirical support. Practical implications: Hotel managers can increase employees’ AC and customer orientation by engaging in AL behaviors. Similarly, management can avoid having employees voluntarily leave their jobs using more AL styles and strengthening employees’ affective bonds to their organization. Originality/value: Prior hospitality studies have rarely focused on AL. This study is the first to analyze AL’s effect on customer orientation and AC’s role as a mediator variable in the relationships between AL and customer orientation and turnover intention, thus integrating all these variables into a single research model.info:eu-repo/semantics/acceptedVersio