Optimum energy partition between data and midamble for channel estimation in TD-CDMA

Channel estimation in the uplink of a TD-CDTMA system can be accomplished by inserting 11 known sequence of symbols at the chip rate, usually in the middle of the burst, and therefore called midamble. In this paper we found the analytical solution to the problem of optimum energy partition, given the total energy per burst, between the midamble and data fields, in joint detected TD-CDMA systems. We show that, given the lengths of the data and midamble, in general the optimal solution requires different amplitude levels. We also show the burst structure in order to reach the optimum energy partition with equal amplitude symbols, and the performance degradation with traditional choices. The analysis is validated, for different channels, by comparison with simulation results of the TD-CDMA radio interlace specified for third generation cellular systems, where gains in terms of signal-to-noise ratio of 0.5-0.9 dB are achieveable

Assessment of Heavy Metal Pollution of Wetland Soils in Ijokodo, Oyo State, Nigeria

Wetlands soils play significant roles in agricultural food production, but are susceptible to heavy metal contamination from recharge waters and/or agrochemicals. This study investigated distribution and level of pollution of heavy metal in soils of Ijokodo wetland, Oyo state, Southwest Nigeria. Twenty soil samples (top and sub soils) were collected randomly within the wetland in October, 2019 and analyzed for Mn, Fe, Cu, Zn, Pb, Cd, Co, Cr and Ni using standard methods. The degree of heavy metal pollution was assessed by comparing metal concentrations to sediment quality guidelines and soil quality thresholds. The results show that soil within the Ijokodo wetland is moderately polluted with cadmium and nickel at concentrations that could cause adverse impact to the wetland ecosystem. The correlation matrix and PCA both show recharge waters, agricultural inputs and parent rock composition as important sources of metals in the wetland. The presence of heavy metals in wetland soils above permissible limits is of human health concern and calls for continuous monitoring of Ijokodo wetland soils to check heavy metal enrichment above the accepted regulatory limits

Efficacy of perindopril in reduction of cardiovascular events among patients with stable coronary artery disease: randomised, double-blind, placebo-controlled, multicentre trial (the EUROPA study)

BACKGROUND: Treatment with angiotensin-converting-enzyme (ACE) inhibitors reduces the rate of cardiovascular events among patients with left-ventricular dysfunction and those at high risk of such events. We assessed whether the ACE inhibitor perindopril reduced cardiovascular risk in a low-risk population with stable coronary heart disease and no apparent heart failure. METHODS: We recruited patients from October, 1997, to June, 2000. 13655 patients were registered with previous myocardial infarction (64%), angiographic evidence of coronary artery disease (61%), coronary revascularisation (55%), or a positive stress test only (5%). After a run-in period of 4 weeks, in which all patients received perindopril, 12218 patients were randomly assigned perindopril 8 mg once daily (n=6110), or matching placebo (n=6108). The mean follow-up was 4.2 years, and the primary endpoint was cardiovascular death, myocardial infarction, or cardiac arrest. Analysis was by intention to treat. FINDINGS: Mean age of patients was 60 years (SD 9), 85% were male, 92% were taking platelet inhibitors, 62% beta blockers, and 58% lipid-lowering therapy. 603 (10%) placebo and 488 (8%) perindopril patients experienced the primary endpoint, which yields a 20% relative risk reduction (95% CI 9-29, p=0.0003) with perindopril. These benefits were consistent in all predefined subgroups and secondary endpoints. Perindopril was well tolerated. INTERPRETATION: Among patients with stable coronary heart disease without apparent heart failure, perindopril can significantly improve outcome. About 50 patients need to be treated for a period of 4 years to prevent one major cardiovascular event. Treatment with perindopril, on top of other preventive medications, should be considered in all patients with coronary heart disease