Reduction of perceptual redundancy for data compression of television signals

Imperial Users onl

Reachiing for the Heavens

The Burj Khalifa, located in Dubai, United Arab Emirates, was crowned by the Council of Tall Buildings and Urban Habitat (CTBUH) as the tallest structure built by man. So striking was the achievement that the CTBUH, in their yearly awards ceremony, created a special category titled Global Icon to do justice for the achievement

Overview of Constitutional Challenges to NSA Collection Activities and Recent Developments

[Excerpt] Beginning in the summer of 2013, media reports of foreign intelligence activities conducted by the National Security Agency (NSA) have been published and are apparently based on unauthorized disclosures of classified information by Edward Snowden, a former NSA contractor. The reports have focused on two main NSA collection activities conducted under the auspices of the Foreign Intelligence Surveillance Act (FISA) of 1978. The first is the bulk collection of telephony metadata for domestic and international telephone calls. The second involves the interception of Internet-based communications and is targeted at foreigners who are not within the United States, but may also inadvertently acquire the communications of U.S. persons. As the public’s awareness of these programs has grown, Members of Congress and the public have increasingly voiced concerns about the constitutionality of these programs. This report provides a description of these two programs and the various constitutional challenges that have arisen in judicial forums with respect to each. Although a brief overview of the constitutional arguments and issues raised in the assorted cases is included, a detailed analysis or evaluation of those arguments is beyond the scope of this report

Comparative Reproductive Ecology Of Female Buffleheads (bucephala Albeola) And Barrow\u27s Goldeneyes (bucephala Islandica) In Central British Columbia

Waterfowl (Anseriformes) generally have high energetic costs for reproduction because they lay large, energy-rich eggs. Consequently, many temperate nesting ducks (Anatinae) occupy seasonally productive environments to meet nutritional requirements for egg production. However, ducks in the genus Bucephala often breed in unproductive boreal and montane regions. This study was conducted to investigate nutritional aspects of reproduction in female Buffleheads (Bucephala albeola) and Barrow\u27s Goldeneyes (Bucephala islandica) breeding in central British Columbia.;Diet composition of breeding female Buffleheads and Barrow\u27s Goldeneyes, which consisted primarily of benthic insects, was similar, providing support for the food defense hypothesis as an explanation for evolution of fixed space territorially in the genus Bucephala.;Mean egg laying interval ({dollar}\pm{dollar}SE) for Buffleheads was 48.36 {dollar}\pm{dollar} 2.35 hr. which was similar to that of Barrow\u27s Goldeneyes that laid, on average, every 45.32 {dollar}\pm{dollar} 1.40 hr. As a consequence of slower rates of egg production, daily energetic costs of reproduction in female Buffleheads and Barrow\u27s Goldeneyes, evaluated relative to their basal metabolic requirements, are among the lowest documented for ducks.;Patterns of lipogenesis differed between female Buffleheads and Barrow\u27s Goldeneyes, but both species catabolized somatic fat for egg production. Buffleheads maintained stable body protein during reproduction, and thus relied exclusively on dietary protein for clutch formation, whereas Goldeneyes catabolized small amounts of somatic protein to produce egg protein in 1993. Use of body protein by a primarily carnivorous duck suggests that protein availability, i.e. invertebrate abundance, in breeding habitats used by Goldeneyes was periodically deficient. Somatic mineral supplied approximately 8% of clutch minerals in Buffleheads and 3% of clutch minerals in Goldeneyes during the 1993 breeding season, but neither species used endogenous minerals for eggshell production in 1994.;Size of lipid and protein reserves did not limit clutch size in either Buffleheads or Barrow\u27s Goldeneyes. Furthermore, clutch size was negatively related to somatic mineral mass in Buffleheads, but positively related to clutch size in Barrow\u27s Goldeneyes. Thus, from a nutritional perspective, only mineral availability limited clutch size in Barrow\u27s Goldeneyes, whereas relatively low rates of somatic tissue catabolism suggested that nutrient availability may not constrain clutch size in Buffleheads

Z(_N)-symmetric field theories and the thermodynamic Bethe ansatz

This thesis is concerned with perturbed conformal field theory, the thermodynamic Bethe ansatz technique and applications to statistical mechanics. In particular, the phase space of two dimensional Z(_N)-symmetric statistical models is examined using these techniques. The aim of the first two chapters is to review some general material concerning statistical mechanics, perturbed conformal field theory, integrable two-dimensional quantum field theory and the thermodynamic Bethe ansatz (TBA) technique. In the third chapter Z(_N)-symmetric statistical theories are discussed and the known features of the phase space of such models are surveyed. The field content of the conformal models in this space (called parafermionic models) is investigated in order to determine which perturbations can be used to investigate the phase space. In the fourth and fifth chapters TBA equations are proposed to describe massless and massive renormalisation flows from the Z(_N)-symmetric conformal theories under self-dual Z(_N)-symmetric perturbations. According to the sign of the perturbation parameter the infrared limits are shown to be either conformal c = 1 or massive theories. The ground state energies of these models can be discovered in all perturbative regimes via the TBA method and the results agree with perturbation theory in ultraviolet and infrared limits. Results from detailed studies of the N = 5, 6..10 models are presented throughout. It is also deduced that the parafermionic models lie exactly at the bifurcation point of the first-order transition region into the Kosterlitz-Thouless region of the Z(_N)-symmetric phase space. The sixth and seventh chapters deal solely with massive perturbations. In chapter six, results from the TBA equations are used to deduce the mass spectrum and the vacuum structure of the underlying scattering theory. In chapter seven, proposals for the massive S-matrices are made. For N odd the mass spectra proposed by the TBA method and that predicted by the S-matrix approach (using the minimality principle) differ. It is suggested therefore, that the N odd S-matrices contain zeroes in the physical strip, violating the minimality principle

Microbial communities regulate nitrogen use efficiency by balancing tradeoff between resource acquisition and growth rate

Microbial nitrogen use efficiency (NUE) is the portion of N uptake that microbes allocate to growth versus mineralize as ammonium and is thus a critical parameter governing the transformation of organic to inorganic nitrogen. Microbial NUE is sensitive to changes in the soil environment, but its microbial controls remain untested. I performed an incubation where identical mesocosms were inoculated with three distinct microbial communities derived from agricultural land management (conventional, organic, and deciduous forest). Through this incubation, I explored three scales at which communities may exercise control over NUE: in how microbes alter their soil environment through system-level processes; through their stoichiometric and community composition; and through community physiology. My results indicate that microbial activity and physiology are most strongly related to NUE in this controlled environment. Specifically, I show that NUE is positively related to microbial growth rate and not resource acquisition. I also empirically demonstrate for the first time that CUE and NUE are positively related. From these results I conclude that microbes may be important regulators of NUE and govern its variation in ways unpredictable by stoichiometric theory alone