Volunteer tourism : the new ecotourism?

One of the more recent forms of tourism to emerge is what has become known as Volunteer Tourism, the practice of individuals going on a working holiday, volunteering their labour for worthy causes. While volunteering is a well-established activity, the combination with tourism is relatively new and has already changed considerably over a very short period. This paper reviews the process by which volunteer tourism has developed, focusing on its transformation from an individual altruistic endeavour to a more commercial form of conventional tourism. The paper reviews the growth in number of websites devoted to volunteer tourism, and discusses the changes that have taken place in the content and focus of these websites, the locations used as destinations and the organisations they represent over the last two decades. It is apparent that over the last two decades the organisations offering volunteer tourist vacations have increasingly focused their attention on conventional commercial tourism markets which is a similar pattern of evolution to that of ecotourism. The paper concludes that volunteer tourism is likely to become increasingly diverse in scale, distribution and focus in the future, in the same way as ecotourism has broadened its market and appeal, but in so doing, will lose more of the distinctive features that characterized its initial form

An abstract specification language for Markov reliability models

Markov models can be used to compute the reliability of virtually any fault tolerant system. However, the process of delineating all of the states and transitions in a model of complex system can be devastatingly tedious and error-prone. An approach to this problem is presented utilizing an abstract model definition language. This high level language is described in a nonformal manner and illustrated by example

The semi-Markov unreliability range evaluator program

The SURE program is a design/validation tool for ultrareliable computer system architectures. The system uses simple algebraic formulas to compute accurate upper and lower bounds for the death state probabilities of a large class of semi-Markov models. The mathematical formulas used in the program were derived from a mathematical theorem proven by Allan White under contract to NASA Langley Research Center. This mathematical theorem is discussed along with the user interface to the SURE program

Dynamic error characteristics of touch trigger probes used with coordinate measuring machines

This paper discusses the dynamic error characteristics of touch trigger probes used with coordinate measuring machines. During the investigation, a number of important parameters have been identified, including measurement speed, probe longitude, approach distance, probe latitude, stylus length/stylus tip diameter, probe orientation, operating mode (scanning and nonscanning), scan pitch, preload spring force (gauging force), probe type, and the surface approach angle. This paper presents the detailed experimental design and the results obtained from the systematic experiments. These results have led to some useful recommendations for the reduction of the probe dynamic errors. Some of these recommendations included the selection of the optimum measurement speed, the setting of the preload spring force, and the choice of the probe type

Development and integration of the capillary pumped loop GAS and Hitchhiker flight experiments

The Capillary Pumped Loop (CPL) is a thermal control system with high density heat acquisition and transport capability. A small spaceflight version of the CPL was built and flown as a GAS experiment on STS 51-D in April 1985 and STS 51-G in June 1985, and as a Hitchhiker-G experiment on STS 61-C in January 1986. The purpose of the experiments was to demonstrate the capability of a capillary pumped system under microgravity conditions for use in the thermal control of large scientific instruments, advanced orbiting spacecraft, and space station components. The development, integration, and test activities of the CPL are described

The HARPS-TERRA project I. Description of the algorithms, performance and new measurements on a few remarkable stars observed by HARPS

Doppler spectroscopy has uncovered or confirmed all the known planets orbiting nearby stars. Two main techniques are used to obtain precision Doppler measurements at optical wavelengths. The first approach is the gas cell method, which consists on the least-squares matching of the spectrum of Iodine imprinted on the spectrum of the star. The second method relies on the construction of a stabilized spectrograph externally calibrated in wavelength. The most precise stabilized spectrometer in operation is HARPS, operated by ESO in La Silla Observatory/Chile. The Doppler measurements obtained with HARPS are typically obtained using the Cross-Correlation Function technique (CCF). It consists of multiplying the stellar spectrum with a weighted binary mask and finding the minimum of such product as a function of the Doppler shift. It is known that CCF is suboptimal in exploiting the Doppler information in the stellar spectrum. Here, we describe an algorithm to obtain precision RV measurements using least-squares matching of each observed spectrum to a high signal-to-noise ratio template derived from the same observations. Such algorithm is implemented in our software called HARPS-TERRA (Template Enhanced Radial velocity Re-analysis Application). New radial velocity measurements on a representative sample of stars observed by HARPS is used to illustrate the benefits of the proposed method. We show that, compared to CCF, template matching provides a significant improvement in accuracy, specially when applied to M dwarfs.Comment: Accepted in ApJ supplement series. Main manuscript contains 40 pages, 17 figures and 6 Tables. Table 7 to 14 (page 41-90) contain the relevant time series. Table 15 contains the HARPS-TERRA, HIRES and PFS RV measurements used in http://arxiv.org/abs/1202.0446. Machine readable tables will the provided in the journal version of the manuscrip

R&D spending and cyclical fluctuations: putting the "technology" in technology shocks

We examine the dynamic properties of an endogenous growth model with an explicit R&D sector in order to evaluate its ability to propagate temporary disturbances into persistent fluctuations in macroeconomic variables. We demonstrate that a large proportion of the variability and persistence of measured Solow residuals can be thought of as reflecting the endogenous accumulation and adaptation of technical knowledge rather than simply exogenous processes. By explicitly modeling R&D, we use a framework in which it is possible to explicitly consider the role of technology in "technology shocks."Research and development