Analysis of Background Noise for Wireless Microwave LAN Channels

Perusal of the details within, should provide the reader with an insight into general wireless indoor communications within the microwave spectrum, with respect to the problems laced, specific to noise corruption of the transmitted signal. Indoor communication systems are difficult to model, due to the largely random nature of the relevant environment, and the compounding factors that degrade system performance. These factors are many and varied, in accordance with the operational topologies of possible application area. However, there exists a common and increasing need to effectively model the communication links in question. Part of this strategy involves having an understanding of what levels of background noise exist within the operational area involved, and to what degree it is variable in accordance with application and link topologies. It is this requirement that provided the catalyst for my investigations. This study investigates the various noise sources evident on the two frequency bands allocated for wireless LAN applications, and considers the relative importance of the findings. As further perusal will reveal, the major disturbance likely to affect such technologies, are microwave ovens, both on a domestic and commercial scale. A lull statistical analysis is presented for the spectrum distribution and corresponding power levels for microwave ovens, with the results being utilised to present an examination of the possible influence that they may have upon the system, and the significance of such claims

Land

Changing climate patterns, economic globalization, population growth, increasing use of natural resources and rapid urbanization are putting pressure on terrestrial ecosystems as never before, and virtually all of them are under stress. Biophysical limits on what is available for human use are real and there are strong signals that these limits are close to being reached or have already been exceeded (Rockström et al. 2009). Even so, the fact that some areas show recent gains in forested area or land reclamation (Lambin and Meyfroidt 2010; Nepstad et al. 2009; Bai et al. 2008) suggests that declines are not inevitable, and indeed that recovery may be possible – even though original ecosystem functions may be modified or pressure on ecosystems may shift elsewhere (Meyfroidt et al. 2010).Fil: Hunsberger, Carol. No especifíca;Fil: Evans, Tom P.. No especifíca;Fil: Aide, T. Mitchell. No especifíca;Fil: Albaladejo Montoro, Juan. No especifíca;Fil: Borras Jr., Saturnino M.. No especifíca;Fil: del Valle, Hector Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Devisscher, Tahia. No especifíca;Fil: Jabbour, Jason. No especifíca;Fil: Kant, Shashi. No especifíca;Fil: López-Carr, David. No especifíca;Fil: Masundire, Hillary. No especifíca;Fil: Pricope, Narcisa G.. No especifíca;Fil: Sánchez-Rodriguez, Roberto. No especifíca;Fil: Abdelhamid, Magdi T.. No especifíca;Fil: Alfthan, Björn. No especifíca;Fil: Ayache, Fethi. No especifíca;Fil: Asefaw Berhe, Asmeret. No especifíca;Fil: Chinweze, Chizoba. No especifíca;Fil: Frélichová, Jana. No especifíca;Fil: Hislop, Lawrence.. No especifíca;Fil: Pan, William K.. No especifíca;Fil: Schulte-Herbrüggen, Björn. No especifíca;Fil: Smith, Jessica. No especifíca;Fil: Souza Jr., Carlos. No especifíca;Fil: Timmins, Tracy L.. No especifíca;Fil: Zulu, Leo C.. No especifíca

Effect of aquaculture on world fish supplies

Global production of farmed fish and shellfish has more than doubled in the past 15 years. Many people believe that such growth relieves pressure on ocean fisheries, but the opposite is true for some types of aquaculture. Farming carnivorous species requires large inputs of wild fish for feed. Some aquaculture systems also reduce wild fish supplies through habitat modification, wild seedstock collection and other ecological impacts. On balance, global aquaculture production still adds to world fish supplies; however, if the growing aquaculture industry is to sustain its contribution to world fish supplies, it must reduce wild fish inputs in feed and adopt more ecologically sound management practices.We thank M. Williams, W. Falcon, V. Spruill, M. Drew, N. Wada, R. Kautsky, K. Jauncey, C. Tirado, R. Hoguet, R. Tatum and R. Mitchell for comments and assistance, and the David and Lucile Packard Foundation for funding