Unidirectional decomposition method for obtaining exact localized waves solutions totally free of backward components

In this paper we use a unidirectional decomposition capable of furnishing localized wave pulses, with luminal and superluminal peak velocities, in exact form and totally free of backward components, which have been a chronic problem for such wave solutions. This decomposition is powerful enough for yielding not only ideal nondiffracting pulses but also their finite energy versions still in exact analytical closed form. Another advantage of the present approach is that, since the backward spectral components are absent, the frequency spectra of the pulses do not need to possess ultra-widebands, as it is required by the usual localized waves (LWs) solutions obtained by other methods. Finally, the present results bring the LW theory nearer to the real experimental possibilities of usual laboratories.Comment: 28 pages, 6 figure

Superluminal Localized Solutions to Maxwell Equations propagating along a waveguide: The finite-energy case

In a previous paper of ours [Phys. Rev. E64 (2001) 066603, e-print physics/0001039] we have shown localized (non-evanescent) solutions to Maxwell equations to exist, which propagate without distortion with Superluminal speed along normal-sized waveguides, and consist in trains of "X-shaped" beams. Those solutions possessed therefore infinite energy. In this note we show how to obtain, by contrast, finite-energy solutions, with the same localization and Superluminality properties. [PACS nos.: 41.20.Jb; 03.50.De; 03.30.+p; 84.40.Az; 42.82.Et. Keywords: Wave-guides; Localized solutions to Maxwell equations; Superluminal waves; Bessel beams; Limited-dispersion beams; Finite-energy waves; Electromagnetic wavelets; X-shaped waves; Evanescent waves; Electromagnetism; Microwaves; Optics; Special relativity; Localized acoustic waves; Seismic waves; Mechanical waves; Elastic waves; Guided gravitational waves.]Comment: plain LaTeX file (12 pages), plus 10 figure

Effect of moderate weight loss on hepatic, pancreatic and visceral lipids in obese subjects

OBJECTIVE: To compare the effects of weight loss on visceral and subcutaneous abdominal fat, liver and pancreas lipid contentand to test the effects of these changes on metabolic improvement observed after weight loss.DESIGN: Weight-loss program designed to achieve a loss of 7--10% of the initial weight.SUBJECTS: 24 obese subjects (13 males and 11 females) with age ranging from 26 to 69 years and body mass index (BMI)30.2 -- 50.5 kgm2. Measurements: weight, BMI, waist circumference, body composition as assessed by dual-energy X-rayabsorptiometry, metabolic variables, leptin, adiponectin, visceral and subcutaneous abdominal fat, liver and pancreas lipidcontent as assessed by magnetic resonance were evaluated before and after weight loss achieved by hypocaloric diet.RESULTS: After a mean body weight decrease of 8.9%, BMI, waist circumference, fat mass, all metabolic variables, homeostasismodel assessment of insulin resistance (HOMA), alanine amino transferase, gamma glutamyl transpeptidase, high-sensitivityC-reactive protein (hs-CRP) and leptin, but not adiponectin and high-density lipoprotein-cholesterol, significantly decreased (allPo0.01). Visceral and subcutaneos abdominal fat, liver and pancreas lipid content significantly decreased (all Po0.01). Percentchanges in liver lipid content were greater (84.1\ub13%) than those in lipid pancreas content (42.3\ub129%) and visceral abdominalfat (31.9\ub115.6%). After weight loss, percentage of subjects with liver steatosis decreased from 75 to 12.5%. Insulin resistanceimprovement was predicted by changes in liver lipid content independently of changes in visceral fat, pancreas lipid content,systemic inflammation, leptin and gender.CONCLUSION: Moderate weight loss determines significant decline in visceral abdominal fat, lipid content in liver andpancreas. Reduction of liver lipid content was greater than that of pancreas lipid content and visceral fat loss. Liver lipidcontent is the strongest predictor of insulin resistance improvement after weight loss