Studying Three Phase Supply in School

The power distribution of nearly all major countries have accepted 3-phase distribution as a standard. With increasing power requirements of instrumentation today even a small physics laboratory requires 3-phase supply. While physics students are given an introduction of this in passing, no experiment work is done with 3-phase supply due to the sheer possibility of accidents while working with such large powers. We believe a conceptual understanding of 3-phase supply would be useful for physics students with hands on experience using a simple circuit that can be assembled even in a high school laboratorys

Long range experimental hydrologic forecasting for the eastern U.S.

We explore a strategy for long-range hydrologic forecasting that uses ensemble climate model forecasts as input to a macroscale hydrologic model to produce runoff and streamflow forecasts at spatial and temporal scales appropriate for water management. Monthly ensemble climate model forecasts produced by the National Centers for Environmental Prediction/Climate Prediction Center global spectral model (GSM) are bias corrected, downscaled to 1/8° horizontal resolution, and disaggregated to a daily time step for input to the Variable Infiltration Capacity hydrologic model. Bias correction is effected by evaluating the GSM ensemble forecast variables as percentiles relative to the GSM model climatology and then extracting the percentiles\u27 associated variable values instead from the observed climatology. The monthly meteorological forecasts are then interpolated to the finer hydrologic model scale, at which a daily signal that preserves the forecast anomaly is imposed through resampling of the historic record. With the resulting monthly runoff and streamflow forecasts for the East Coast and Ohio River basin, we evaluate the bias correction and resampling approaches during the southeastern United States drought from May to August 2000 and also for the El Niño conditions of December 1997 to February 1998. For the summer 2000 study period, persistence in anomalous initial hydrologic states predominates in determining the hydrologic forecasts. In contrast, the El Niño-condition hydrologic forecasts derive direction both from the climate model forecast signal and the antecedent land surface state. From a qualitative standpoint the hydrologic forecasting strategy appears successful in translating climate forecast signals to hydrologic variables of interest for water management

(SI10-057) Effect of Time-delay on an SIR Type Model For Infectious Diseases with Saturated Treatment

This study presents the complex dynamics of an SIR epidemic model incorporating a constant time-delay in incidence rate with saturated type of treatment rate. The system is studied to observe the effect of time lag in the asymptotic stability of endemic equilibrium states. We also establish global asymptotic stability of both disease-free and endemic equilibrium states by Lyapunov direct method with the help of suitable Lyapunov functionals. The existences of periodic solutions are ensured for the suitable choice of delay parameter. Finally, we perform numerical simulations supporting the analytical findings as well as to observe the effect of time-delay. The theoretical and numerical results together show delay can have both stabilizing and destabilizing effects on the system. Moreover, we observe that infection may die out from the population when the corresponding system without delay has two endemic equilibrium for appropriate choice of time-delay

To evaluate the hemoglobin concentration, lipid peroxidation and antioxidant status in patients with chronic kidney disease

Background: Oxidative stress plays an important role in the progression of CKD as well as in many of the complications associated with the disease. ROS promotes inflammation, accelerated ageing, fibrosis and apoptosis leading to progression of CKD. Therefore, the present study was carried out to evaluate the serum markers for early diagnosis of patients at different stages of chronic kidney disease.Methods: The study group consisted of 50 patients with chronic kidney disease who were on conservative treatment with the age group of 20 to 60 years. Based on the creatinine clearance values the patients were assigned in to 3 groups; Stage 3, Stage- 4 and Stage- 5 as per NKF DOQI guidelines. Control group consisted of 50 age and sex matched, non-diabetic, nonsmoker healthy volunteers. About 5 ml of blood was collected and serum was used for the estimation of superoxide dismutase, ceruloplasmin and malondialdehyde and haemoglobin level using standard methods. The data was analyzed by applying student’s t test. The p value of ≤0.05 was taken as the level of significance.Results: The haemoglobin concentration in all the 3 CKD stages was found to be significantly decreased (p<0.000) whereas, the serum malondialdehyde (MDA) was significantly increased (p=0.000) in patients with CKD. But serum SOD and ceruloplasmin levels of normal and patients with CKD showed significant decline (p<0.000) only in stage 5 whereas, in stage-2 and stage-3 patients it did not show significant variation.Conclusions: The results of the study reinforce the possibility that antioxidant supplementation may be helpful in correcting anaemia in chronic kidney disease. Treatment of renal anaemia is an effective intervention to ensure better quality of life, to prevent adverse cardiovascular outcomes and to retard the progression of chronic kidney disease so as to reduce the burden of end stage renal disease in the long run

Correlation of hemoglobin with creatinine clearance, antioxidant status, lipid peroxidation and ceruloplasmin in patients with chronic kidney disease

Background: Anaemia in CRF is caused primarily by a combination of depressed erythropoiesis and shortened erythrocyte lifespan caused by oxidative stress. Therefore, the present study was designed to investigate the correlation between Hb concentration and antioxidant and lipid peroxidation levels.Methods: The study group consisted of 50 patients with chronic kidney disease who were on conservative treatment with the age group of 20 to 60 years. Based on the creatinine clearance values the patients were assigned in to 3 groups; Stage 3, Stage- 4 and Stage- 5 as per NKF DOQI guidelines. Control group consisted of 50 age and sex matched, non-diabetic, non-smoker healthy volunteers. About 5 ml of blood was collected and serum was used for the estimation of superoxide dismutase, ceruloplasmin and malondialdehyde and haemoglobin level using standard methods. The correlations between the different groups are performed by applying Pearson’s correlation test. The p value of ≤0.05 was taken as the level of significance.Results: A positive correlation of Hb with creatinine clearance (r=0.46, p=0.001), SOD level(r=0.4, p=0.009), serum ceruloplasmin (r=0.3, p=0.07) was observed. Significant positive correlation was found between creatinine clearance and SOD level (r=0.4, p=0.008), ceruloplasmin (r=0.3, p=0.04). A negative correlation was obtained between serum malondialdehyde levels and haemoglobin concentration (r=-0.4, p=0.007) and between creatinine clearance and MDA levels (r=-0.4, p=0.01).Conclusions: The study provides a better understanding of the biochemical parameters underlying anaemia in chronic kidney disease. The increased production of ROS and deficiency of antioxidant enzymes altered the oxidant and antioxidant equilibrium in the plasma of CKD patients