65 research outputs found

    A system of ODEs for a Perturbation of a Minimal Mass Soliton

    Full text link
    We study soliton solutions to a nonlinear Schrodinger equation with a saturated nonlinearity. Such nonlinearities are known to possess minimal mass soliton solutions. We consider a small perturbation of a minimal mass soliton, and identify a system of ODEs similar to those from Comech and Pelinovsky (2003), which model the behavior of the perturbation for short times. We then provide numerical evidence that under this system of ODEs there are two possible dynamical outcomes, which is in accord with the conclusions of Pelinovsky, Afanasjev, and Kivshar (1996). For initial data which supports a soliton structure, a generic initial perturbation oscillates around the stable family of solitons. For initial data which is expected to disperse, the finite dimensional dynamics follow the unstable portion of the soliton curve.Comment: Minor edit

    Studies on the anti-obesity activity of zinc-α2-glycoprotein in the rat

    Get PDF
    OBJECTIVE: To investigate the anti-obesity effect of the adipokine zinc-a(2)-glycoprotein (ZAG) in rats and the mechanism of this effect. SUBJECTS: Mature male Wistar rats (540 ± 83 g) were administered human recombinant ZAG (50 ”g per 100 g body weight given intravenously daily) for 10 days, while control animals received an equal volume of phosphate-buffered saline (PBS). RESULTS: Animals treated with ZAG showed a progressive decrease in body weight, without a decrease in food and water intake, but with a 0.4 °C rise in body temperature. Body composition analysis showed loss of adipose tissue, but an increase in lean body mass. The loss of fat was due to an increase in lipolysis as shown by a 50% elevation of plasma glycerol, accompanied by increased utilization of non-esterified fatty acids, as evidenced by the 55% decrease in plasma levels. Plasma levels of glucose and triglycerides were also reduced by 36-37% and there was increased expression of the glucose transporter 4 in both skeletal muscle and adipose tissue. Expression of the lipolytic enzymes adipose triglyceride lipase and hormone-sensitive lipase in the white adipose tissue (WAT) were increased twofold after ZAG administration. There was almost a twofold increased expression of uncoupling proteins 1 and 3 in brown adipose tissue and WAT, which would contribute to increased substrate utilization. Administration of ZAG increased ZAG expression twofold in the gastrocnemius muscle, BAT and WAT, which was probably necessary for its biological effect. CONCLUSION: These results show that ZAG produces increased lipid mobilization and utilization in the rat

    Does it pay to be sustainable? Looking inside the black box of the relationship between sustainability performance and financial performance

    Get PDF
    The last three decades have witnessed a huge amount of research exploring the linkage between companies' sustainability performance (SP), sustainability disclosure and financial performance (FP). Researchers have applied various methods and techniques to investigate this relationship, yet the results remain equivocal. In this article, we look inside this black box by considering various manifestations of sustainability practices and investigating their link with FP. We apply a manual content analysis technique to analyse the sustainability reports of the 100 best-performing US firms. Our results reveal that fragmentation in the results is caused by the SP measurement. Additionally, we note that the interlinkages between different SP dimensions and sub-dimensions are weak and somewhat contradictory. The results help draw important policy implications for the development of an SP reporting framework

    Cancer and fertility preservation: international recommendations from an expert meeting

    Get PDF
    • 

    corecore