1,721,808 research outputs found
English for international tourism: The promotion of Brescia and its province
No full textThe paper aims to describe the use of English in a context of international tourism. This is done through a corpus-based analysis of the website of Bresciatourism, a non-profit company that promotes Brescia and its territory both in Italy and abroad.
The methodology adopted combines corpus linguistics methods with a socio-linguistic approach to the analysis of the verbal technique of keywords and keying (i.e. the notion of keyness at the lexical and semantic levels). The data presented provide some empirical findings to the discussion of how this verbal technique, variously discussed in semiotics (Dann 1996) as one of the strategies which realise the rhetoric of tourism, is used in a specific context of international tourism, and how the strategy correlates to either one or another of the three major theoretical perspectives on tourism discussed in semiotics - the perspective of play; perspective of strangerhood; perspective of authenticity.
A brief conclusion is drawn before a short presentation of the potential interest of these findings for the ESP and ELF domains is put forward
Cascade lasing optimization in Dy-doped ZBLAN fiber lasers for efficient yellow emission
No full textThe interest in Fiber Lasers (FLs) operating in the yellow range of the visible spectrum has greatly increased alongside the improvement of blue GaN pump laser diodes, as well as the recent fabrication of high-quality Dysprosium (Dy) doped fluoride fibers, to be used as active medium [1,2]. Even though alternative yellow sources are available, FLs are cost-effective, compact, and efficient solutions that can provide advantages for applications in many fields (biomedicine, ophthalmology, spectroscopy, etc.) [1]. The 4F9/2 → 6H13/2 transition of Dy3+ ions has already been exploited to experimentally demonstrate different types of yellow FLs via pumping at around 450 nm, the slope-efficiency of which is negatively affected by signal excited state absorption from the lower laser level. Recently, cascade lasing at 3 μm through the 6H13/2 → 6H15/2 transition was proposed to mitigate this effect [2]. However, a thorough numerical analysis of cascade lasing providing key information for design optimization of yellow fiber-based sources is not available in literature
Power scaling of normal-dispersion continuum generation using higher-order modes in microstructured optical fibers
Full text linkThe use of a higher-order HE12-like mode to produce weak normal dispersion over a substantial wavelength range in a microstructured optical fiber is investigated numerically. It is shown that the effective area, and thereby the pulse energy, can in this way be scaled by an order of magnitude compared to using the fundamental mode in a single-mode fiber. Multimode nonlinear simulations indicate that nonlinear mode coupling will not disturb single-mode operation in the HE12 mode at least up to the threshold where polarization modulation instability sets in
Optimizing Dysprosium-Doped Fiber Lasers for Direct Yellow Emission: A Comprehensive Numerical Analysis
No full textPower scaling of normal-dispersion continuum generation: Merging fiber and light structuring
No full textThe use of higher-order modes (HOMs) is emerging as a new route to scale the core size, and thereby operational power levels for nonlinear processes, while retaining desired dispersion properties. The peculiar guidance properties of microstructured optical fibers (MOFs) imply distinct advantages for HOM-based devices in terms of limiting mode competition, and extending the useful spectral guidance window. This contribution shows how combined tailoring of MOF structures and field profiles can lead to order-of-magnitude gains in the power levels of all-normal supercontinuum generation
Cross-company jump spillover and the role of news
Full text linkWe study how jumps spillover and the cross-company impact of firm-specific unscheduled news on jumps between economic sectors. To this end, we employ high-frequency data of 220 constituents of the Russell 3000 index equally divided into eleven sectors. Using conditional jump probabilities, we find that jump spillover is a pervasive phenomenon enhanced when jumps cluster and that firm-specific news, especially from the financial sector, boosts the jump spillover effect. Volatility following spillover jumps is significantly higher than usual, except when firm-specific news is released around the jump provoking the spillover
Financing Firms' Network: The Italian case
No full textIn this study we aim to treat firms' networks as an instrument for firms to promote growth, enhancing their performances and improving the conditions of access to credit. The analysis focuses on the Italian context where has been recently introduced the network contract (Italian Legislative Decree no. 5/2009) - the first legislation in Europe to regulate firms' networks. The purpose of this work is to find the differences in the performance and financial variables of Italian firms that have signed network contracts with a control sample of non-networked firms and to investigate the characteristics of network contracts that involve the best performance for networked firms. We found that network contracts have a positive effect on the financial aspects and profitability of firms
Influence of FBG quality on yellow Dy-doped ZBLAN fiber lasers performance
No full textMIR cascade lasing is a solution to mitigate the negative impact of excited state absorption on the performance of yellow lasers made of ZBLAN fibers doped with Dysprosium. A low-loss cavity with nearly ideal mirror reflectivity in both yellow and MIR wavelength ranges yields optimal results, but fabricating FBGs with extremely high reflectivity remains challenging in fluoride glasses. In this work, we use our matrix-based model to provide insights into the influence of FBGs quality on the performance of yellow Dy-doped ZBLAN FLs with MIR cascade lasing. Results reveal that reducing the front mirror reflectivity at the yellow wavelength lowers the laser slope efficiency, whereas decreasing the reflectivity of the mirrors constituting the cavity for the MIR emission leads to an increase in the threshold
Numerical optimization of tunable Dy-doped ZBLAN fiber lasers for yellow emission
No full textThe interest in fiber lasers operating in the yellow range of the visible spectrum has greatly increased alongside the improvement of blue pump laser diodes, as well as the recent fabrication of high-quality Dysprosium-doped fluoride fibers, to be used as the active medium. In this work, a matrix-based simulation model which exploits the rate equations was applied to examine the influence of excited state absorption on the performances of a tunable yellow source. Simulation results provide useful guidelines to improve the tunability range of the yellow fiber laser, by properly selecting the reflectivity of the output mirror and the active fiber length
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