Browsing by Subject "Limits"

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Open Access
Analysis of the generation of amplitude-squeezed light with Gaussian-beam degenerate optical parametric amplifiers
(OSA Publishing, 2001-06) Köprülü, K. G.; Aytür, O.
We investigate the generation of amplitude-squeezed states with degenerate optical parametric amplifiers that are pumped by focused Gaussian beams. We present a model that facilitates the calculation of the squeezing level for an experimentally realistic cofiguration in which there is a Gaussian input signal beam that has the same confocal parameter and waist location as the Gaussian pump beam, with no restriction on the interaction length-to-confocal parameter ratio. We show that the 3-dB squeezing limit that was thought to be imposed by the Gaussian pump profile can be exceeded in the (previously uninvestigated) tight-focusing regime. We find the maximum possible amplitude squeezing in this regime to be 4.65 dB. However, it is possible to increase the squeezing level further by spatially filtering the tails of the output signal beam, resulting in squeezing levels in excess of 10 dB. (C) 2001 Optical Society of America.
Open Access
Limits to community participation in the tourism development process in developing countries
(Pergamon Press, 2000-12) Tosun, C.
This study deals with a normative concept of participatory development approach, which originates in the developed world. In particular, it analyses and explains the limitations to the participatory tourism development approach in the context of developing countries. It was found that there are operational, structural and cultural limits to community participation in the TDP in many developing countries although they do not equally exist in every tourist destination. Moreover, while these limits tend to exhibit higher intensity and greater persistence in the developing world than in the developed world, they appear to be a reflection of prevailing socio-political, economic and cultural structure in many developing countries. On the other hand, it was also found that although these limitations may vary over time according to types, scale and levels of tourism development, the market served, and cultural attributes of local communities, forms and scale of tourism developed are beyond the control of local communities. It concludes that formulating and implementing the participatory tourism development approach requires a total change in socio-political, legal, administrative and economic structure of many developing countries, for which hard political choices and logical decisions based on cumbersome social, economic and environmental trade-offs are sine qua non alongside deliberate help, collaboration and co-operation of major international donor agencies, NGOs, international tour operators and multinational companies. (C) 2000 Elsevier Science Ltd. All rights reserved.