Suppression of stimulated Brillouin scattering in optical fibers using a linearly chirped diode laser

The output of high power fiber amplifiers is typically limited by stimulated Brillouin scattering (SBS). An analysis of SBS with a chirped pump laser indicates that a chirp of 2.5 × 10^(15) Hz/s could raise, by an order of magnitude, the SBS threshold of a 20-m fiber. A diode laser with a constant output power and a linear chirp of 5 × 10^(15) Hz/s has been previously demonstrated. In a low-power proof-of-concept experiment, the threshold for SBS in a 6-km fiber is increased by a factor of 100 with a chirp of 5 × 10^(14) Hz/s. A linear chirp will enable straightforward coherent combination of multiple fiber amplifiers, with electronic compensation of path length differences on the order of 0.2 m

Free Vibrational Effect of Foot Bridge with Compressive Forces

This paper examines the free vibrational effect of a footbridge with compressive forces. The governing partial differential equation were analysed to determine the behaviour of the system under consideration. The methods of series solution and numerical method were used to solve the governing equation. Result revealed there is no noticeable effect of damping in the system as the motion of deflection remains constant for all values of the damping coefficient. Also, the lateral displacement increases for various values of spring constant

Cardiovascular risk factors and cognitive decline in older people with type 2 diabetes

AIMS/HYPOTHESIS: The aim of this work was to assess the role of well-established cardiovascular risk factors in the late-life cognitive decline of patients with type 2 diabetes. METHODS: Data from 831 participants (aged 60-75 years) attending the 4 year follow-up of the Edinburgh Type 2 Diabetes Study (ET2DS) were used. Smoking history (pack-years), BP, HbA1c, plasma glucose and cholesterol were determined at baseline clinics (single time measurements) and/or from serial data recorded on a clinical management database from diagnosis until recruitment ('historical' data). Principal component analysis derived a factor, g, of general ability from seven cognitive tests. Linear regression models of follow-up g were adjusted for baseline g to represent 4 year cognitive change. 'Accelerated late-life cognitive decline' was defined as scoring in the lowest tertile of '4 year cognitive change' regression scores. Analyses controlled for age and sex. RESULTS: A baseline history of moderate/heavy smoking (>/= 10 pack-years) and a 1% increased historical HbA1c (equivalent to an increase by 11 mmol/mol) predicted a 64% (OR 1.64; 95% CI 1.14, 2.34; p = 0.007) and 21% (OR 1.21; 95% CI 1.00, 1.45; p = 0.046) increased risk of accelerated cognitive decline, respectively. When treated as continuous measures, higher pack-years, historical HbA1c and historical BP emerged as significant independent predictors of 4 year decline in g (standardised beta range -0.07 to -0.14; all p </= 0.05). CONCLUSIONS/INTERPRETATION: Increased smoking and poorer glycaemic control (with relatively weaker findings for BP) during the life-course were independently associated with accelerated late-life cognitive decline. Where possible, evaluation is warranted of these risk factors as targets for intervention to reduce the burden of cognitive impairment in diabetes

DYNAMIC RESPONSE OF RAYLEIGH BEAM ON WINKLER FOUNDATION SUBJECTED TO PARTIALLY DISTRIBUTED MOVING LOAD

Dynamic response of Euler-Bernoulli beam subjected to concentrated moving load was investigated in this paper. The governing equation of fourth order partial differential equation was reduced to an ordinary differential equation using Series solution. The reduced second order differential equation was then solved using finite difference method. Numerical result was presented and it is found that the dynamic response of the beam initially moves in a steady state before deflecting and the deflected amplitude increases as the axial force, distance covered by the load, Mass of the load, speed at which the load moves increases but decreases as the length of the load, coefficient of the foundation increases. This study also conclude that R0 has no/little effects on the structure of the beam

Plasma soluble P-selectin correlates with triglycerides and nitrite in overweight/obese patients with schizophrenia

Background: Soluble P-selectin (sP-selectin) is associated with risk factors for cardiovascular disease (CVD) but this association has not been evaluated in patients with schizophrenia. This study primarily evaluated the association of sP-selectin with plasma lipids and nitrite (NO2-) respectively in overweight/obese adults with schizophrenia

ANALYTICAL-NUMERICAL METHOD FOR SOLVING NONLINEAR DYNAMICAL SYSTEMS

This paper investigates the analytical-numerical method for solving nonlinear dynamical systems. The governing equation of partial differential equation of order four was transformed to Ordinary differential equation using analytical method. The finite difference method was used to transform the approximate governing equation. It was shown from the graph of deflection against distance that the deflection increases as the value of distance increases and also shown from the graph of deflection against time that the deflection increases with increase in time. The result is in agreement with the existing result