Iterative method for the design of DFT filter Bank

Multirate adaptive filters have numerous advantages such as low computational load, fast convergence, and parallelism in the adaptation. Drawbacks when using multirate processing are mainly related to aliasing and reconstruction effects. These effects can be minimized by introducing appropriate problem formulation and employing sophisticated optimization techniques. In this paper, we propose a formulation for the design of a filter bank which controls the distortion level for each frequency component directly and minimizes the inband aliasing and the residual aliasing between different subbands. The advantage of this problem formulation is that the distortion level can be weighted for each frequency depending on the particular practical application. A new iterative algorithm is proposed to optimize simultaneously over both the analysis and the synthesis filter banks. This algorithm is shown to have a unique solution for each iteration. For a fixed distortion level, the proposed algorithm yields a significant reduction in both the inband aliasing and the residual aliasing levels compared to existing methods applied to the numerical examples.     

Structure determination of CaMgGeO4

The crystal structure of CaMgGeO₄ is described. CaMgGeO₄, M_r = 200.9, orthorhombic, Pnam, A = 11.285(5) Å, B = 5.016(2) Å, C = 6.435(2) Å, V = 364.36 ų, Dx = 3.664 Mg/m³.λ(MoK_a = 0.71069 Å, F(000) = 384, room temperature, final R = 0.045 for 1752 observed reflections. The structure is isomorphous with CaMgSiO₄ (monticellite).     

Energy efficiency, carbon emissions and economic development in Venezuela

Venezuela's vast natural resource base has largely shaped the nation's economic and energy-use patterns. Major opportunities exist for improving the efficiency of energy use in Venezuela and, consequently, restraining the growth of energy-related carbon emissions. This paper presents a detailed report of one potential development path for Venezuela and estimates the ensuing levels of energy demand and CO₂ emissions associated with pursuing this path through the year 2025. The results indicate that by adopting a development strategy that incorporates structural changes in the economy, fuel-switching measures and improved end-use efficiencies, Venezuela can introduce energy efficiency and carbon restraints as part of its economic development process.     

Experiments of Fast Learning with High Order Boltzmann Machines

This work reports the results obtained with the application of High Order Boltzmann Machines without hidden units to construct classifiers for some problems that represent different learning paradigms. The Boltzmann Machine weight updating algorithm remains the same even when some of the units can take values in a discrete set or in a continuous interval. The absence of hidden units and the restriction to classification problems allows for the estimation of the connection statistics, without the computational cost involved in the application of simulated annealing. In this setting, the learning process can be sped up several orders of magnitude with no appreciable loss of quality of the results obtained.     

Mediastinal space-occupying lesion with reduced perfusion of the left lung. Thoracic aortic aneurysm with compression of the left pulmonary artery

CONTEXT: An increase in the recreational use of personal watercraft (PWC) raises concern about an increase in associated injuries on a national level. OBJECTIVE: To estimate the relative frequency, types of injury, and demographic features of persons injured while using PWC in the United States. DESIGN: Case series. SETTING: Emergency department (ED) visits to hospitals participating a national probability sample. PARTICIPANTS: All persons treated for PWC-related injury from January 1,1990, through December 31, 1995. RESULTS: An estimated 32954 persons (95% confidence interval [CI], 22919-42989) with PWC-related injuries were treated in US hospital EDs, of which 3.5% were hospitalized. Personal watercraft-related injuries have increased significantly from an estimated 2860 in 1990 to more than 12000 in 1995. During this period, the number of PWC in operation increased 3-fold from approximately 241500 in 1990 to an estimated 760000 in 1995. The most prevalent diagnoses were lacerations, contusions, and fractures. MAIN OUTCOME MEASURES: The estimated number and percentage of patients treated in EDs for PWC-related injuries, by year, age, sex, and the number and rate per 1000 of PWC in operation by year. CONCLUSIONS: Since 1990, there has been at least a 4-fold increase in injuries associated with an increase in the recreational use of PWC. The rate of ED-treated injuries related to PWC was about 8.5 times higher (95% CI, 8.2-8.8; 1992 data) than the rate of those from motorboats. Specific training and adult supervision is recommended for minors using PWC. Furthermore, medical practitioners should encourage personal flotation device use and other protection for their patients who are known water enthusiasts.