Tourism and Empirical Applications of International Trade Theory: A Multi-Country Analysis

This paper examines the application of quantitative techniques to further our understanding of international trade theory with respect to tourism flows. The analyses are based on the construction of Balassa and Grubel-Lloyd Indices, as well as the construction of dynamic indices. The results of the analyses suggest that international trade theory has much to offer the study of international tourism flows. Many countries seem to specialize as both exporters and importers of tourism services. The analyses also explore the theoretical assertion that intra-industry trade is likely to be of importance in understanding international tourism flows

Tourism and Empirical Applications of International Trade Theory: A Multi-Country Analysis

This paper examines the application of quantitative techniques to further our understanding of international trade theory with respect to tourism flows. The analyses are based on the construction of Balassa and Grubel-Lloyd Indices, as well as the construction of dynamic indices. The results of the analyses suggest that international trade theory has much to offer the study of international tourism flows. Many countries seem to specialize as both exporters and importers of tourism services. The analyses also explore the theoretical assertion that intra-industry trade is likely to be of importance in understanding international tourism flows

Sensory substitution for space gloves and for space robots

Sensory substitution systems for space applications are described. Physical sensors replace missing human receptors and feed information to the interpretive centers of a different sense. The brain is plastic enough so that, with training, the subject localizes the input as if it were received through the missing receptors. Astronauts have difficulty feeling objects through space suit gloves because of their thickness and because of the 4.3 psi pressure difference. Miniature force sensors on the glove palm drive an electrotactile belt around the waist, thus augmenting the missing tactile sensation. A proposed teleoperator system with telepresence for a space robot would incorporate teleproprioception and a force sensor/electrotactile belt sensory substitution system for teletouch

Unravelling Active Galactic Nuclei

A complete flat-spectrum radio-loud sample of AGN includes a significant fraction of Seyfert-like AGN including a NLS1. Analysis of their optical spectra suggests that the reddest continuum colours are either associated with AGN in nearby resolved galaxies, or distant quasars showing relatively narrow permitted emission lines.Comment: Poster contribution presented at the Joint MPE,AIP,ESO workshop on NLS1s, Bad Honnef, Dec. 1999, to appear in New Astronomy Reviews; also available at http://wave.xray.mpe.mpg.de/conferences/nls1-worksho

Estimating and calibrating the amount of building-related construction and demolition waste in urban China

One side effect of the unprecedented urbanization in China is the large amount of building-related construction and demolition (C&D) waste generated during the process. It is an enigma why such statistics as C&D waste generation are absent from the literature in spite of their importance to devising sensible interventions to deal with the C&D waste related problems. This paper aims to estimate the amount of C&D waste at the country level. It does so by adopting a methodology utilizing national statistical data and the average amounts of waste generated at job sites. Furthermore, the estimation is undergone a thorough calibration against various independent sources before it can be accepted confidently. It is finally estimated that approximately 1.13 billion tons of C&D materials were generated in China during 2014, which has declined from a plateau of building activities and C&D waste generation in the early 2010s. The paper provides some useful references for devising appropriate C&D waste reduction, reuse, or recycling strategies. The paper also offers useful commentary on methodology to estimate C&D waste generation at an urban level, particularly in situations where data availability is erratic.postprin

Making optical atomic clocks more stable with 10−1610^{-16} level laser stabilization

The superb precision of an atomic clock is derived from its stability. Atomic clocks based on optical (rather than microwave) frequencies are attractive because of their potential for high stability, which scales with operational frequency. Nevertheless, optical clocks have not yet realized this vast potential, due in large part to limitations of the laser used to excite the atomic resonance. To address this problem, we demonstrate a cavity-stabilized laser system with a reduced thermal noise floor, exhibiting a fractional frequency instability of $2 \times 10^{-16}$. We use this laser as a stable optical source in a Yb optical lattice clock to resolve an ultranarrow 1 Hz transition linewidth. With the stable laser source and the signal to noise ratio (S/N) afforded by the Yb optical clock, we dramatically reduce key stability limitations of the clock, and make measurements consistent with a clock instability of $5 \times 10^{-16} / \sqrt{\tau}$

Role of the conduction electrons in mediating exchange interactions in Heusler alloys

Because of large spatial separation of the Mn atoms in Heusler alloys the Mn 3d states belonging to different atoms do not overlap considerably. Therefore an indirect exchange interaction between Mn atoms should play a crucial role in the ferromagnetism of the systems. To study the nature of the ferromagnetism of various Mn-based semi- and full-Heusler alloys we perform a systematic first-principles calculation of the exchange interactions in these materials. The calculation of the exchange parameters is based on the frozen-magnon approach. The calculations show that the magnetism of the Mn-based Heusler alloys depends strongly on the number of conduction electrons, their spin polarization and the position of the unoccupied Mn 3d states with respect to the Fermi level. Various magnetic phases are obtained depending on the combination of these characteristics. The Anderson's s-d model is used to perform a qualitative analysis of the obtained results. The conditions leading to diverse magnetic behavior are identified. If the spin polarization of the conduction electrons at the Fermi energy is large and the unoccupied Mn 3d states lie well above the Fermi level, an RKKY-type ferromagnetic interaction is dominating. On the other hand, the contribution of the antiferromagnetic superexchange becomes important if unoccupied Mn 3d states lie close to the Fermi energy. The resulting magnetic behavior depends on the competition of these two exchange mechanisms. The calculational results are in good correlation with the conclusions made on the basis of the Anderson s-d model which provides useful framework for the analysis of the results of first-principles calculations and helps to formulate the conditions for high Curie temperature.Comment: 16 pages, 9 figures, 2 table

Stakeholders' willingness to pay for enhanced construction waste management: a Hong Kong study

Based on the polluter pays principle, construction waste disposal charging schemes (CWDCS) have been deployed by various economies as one of the most effective ways of managing construction waste. Nevertheless, a means of rationalizing these schemes has not been well documented. Using the economic technique of contingent valuation method (CVM), this study aims to investigate stakeholders’ willingness to pay (WTP) for enhanced construction waste management (CWM) with a view to providing a scientific foundation for CWDCS rationalization. In considering this WTP in light of repeated exhortations that all stakeholders play a role in the management of construction waste, the study is unique. To ascertain stakeholders’ WTP, a payment card-style questionnaire survey was designed and administered to Hong Kong’s major CWM stakeholders in February 2014. Interestingly, the results show that there is no statistically significant variation in the WTP of different stakeholder groups. The average maximum WTP is around HK232/t for landfill disposal of C&D waste, HK186/t for off-site sorting facility (OSF) disposal, and HK$120/t for public fill reception facility (PFRF) disposal. These values are higher than the existing CWDCS charges (HK$125/t for landfilling, HK$100/t for OSF disposal, and HK$27/t for PFRF disposal) but much lower than the charges proposed to the government. This research provides not only a scientific foundation for the ongoing debate on changes to Hong Kong’s CWDCS, but also a valuable reference for other economies facing the challenge of developing charging schemes to deal with construction waste.postprin