GEOPHYSICAL INVESTIGATION OF GROUND SUBSIDENCE: A CASE STUDY OF A BEVERAGE FACTORY SITE IN EDO STATE, NIGERIA

A geophysical investigation involving the electrical resistivity and gravity methods was carried out within the premises of a Beverage Factory in Edo State. The investigation was to enable the determination of the cause(s) of a ground subsidence within the premises of the boilers. The vertical electrical sounding interpretation results show that the premises is underlain by sands with intercalation of clay/sandy clay in places. The layers show lateral continuity. The residual gravity anomalies are generally flat indicating near homogeneous subsurface sequence devoid of lateral discontinuities such as sinkholes/ cavities or faults. A synthesis of the results show that the ground subsidence is not precipitated by collapsed geologic feature such as sinkholes/ cavities but boiler load induced differential settlement arising from near surface incompetent (clayey) substratum, in the premises of the boilers. KEY WORDS: Ground subsidence, Vertical electrical sounding, Gravity anomalies, and Incompetent substratum. Global Jnl Geological Sciences. Vol.2(1) 2004: 153-16

Integrated VLF - Electromagnetic And Electrical Resistivity Survey For Groundwater In A Crystalline Basement Complex Terrain Of Southwest Nigeria

Very Low Frequency Electromagnetic (VLF-EM) and Electrical Resistivity (ER) methods were integrated in a feasibility study of a basement complex area for groundwater development. Linear features, suspected to be basement fractures, inferred from the VLF - EM anomaly curves, were confirmed by subsurface geoelectric images developed from interpretation results of the Vertical Electrical Soundings (VES). The delineated basement fractures were penetrated by three test boreholes at various depth ranges of between 7.0 and 13.0 m beneath Borehole (BH) 3 & 4 and 9.0 - 42 m beneath BH5 for unconfined fractures and 36.0 - 38.0 m beneath BH3 & 4 and 128.0 - 188.0 m beneath BH5 for confined fractures. Borehole yields vary from 0.33 - 2.0 l/s, where two abortive (dry) boreholes (BH1 & 2) were previously drilled. KEY WORDS: VLF - EM, Electrical Resistivity, Linear Features, Groundwater Development, Basement Complex Area. Global Journal of Geological Sciences Vol.3(1) 2005: 71-8

Effect of transcatheter aortic valve implantation vs surgical aortic valve replacement on all-cause mortality in patients with aortic stenosis

Importance: Transcatheter aortic valve implantation (TAVI) is a less invasive alternative to surgical aortic valve replacement and is the treatment of choice for patients at high operative risk. The role of TAVI in patients at lower risk is unclear. Objective: To determine whether TAVI is noninferior to surgery in patients at moderately increased operative risk. Design, Setting, and Participants: In this randomized clinical trial conducted at 34 UK centers, 913 patients aged 70 years or older with severe, symptomatic aortic stenosis and moderately increased operative risk due to age or comorbidity were enrolled between April 2014 and April 2018 and followed up through April 2019. Interventions: TAVI using any valve with a CE mark (indicating conformity of the valve with all legal and safety requirements for sale throughout the European Economic Area) and any access route (n = 458) or surgical aortic valve replacement (surgery; n = 455). Main Outcomes and Measures: The primary outcome was all-cause mortality at 1 year. The primary hypothesis was that TAVI was noninferior to surgery, with a noninferiority margin of 5% for the upper limit of the 1-sided 97.5% CI for the absolute between-group difference in mortality. There were 36 secondary outcomes (30 reported herein), including duration of hospital stay, major bleeding events, vascular complications, conduction disturbance requiring pacemaker implantation, and aortic regurgitation. Results: Among 913 patients randomized (median age, 81 years [IQR, 78 to 84 years]; 424 [46%] were female; median Society of Thoracic Surgeons mortality risk score, 2.6% [IQR, 2.0% to 3.4%]), 912 (99.9%) completed follow-up and were included in the noninferiority analysis. At 1 year, there were 21 deaths (4.6%) in the TAVI group and 30 deaths (6.6%) in the surgery group, with an adjusted absolute risk difference of −2.0% (1-sided 97.5% CI, −∞ to 1.2%; P < .001 for noninferiority). Of 30 prespecified secondary outcomes reported herein, 24 showed no significant difference at 1 year. TAVI was associated with significantly shorter postprocedural hospitalization (median of 3 days [IQR, 2 to 5 days] vs 8 days [IQR, 6 to 13 days] in the surgery group). At 1 year, there were significantly fewer major bleeding events after TAVI compared with surgery (7.2% vs 20.2%, respectively; adjusted hazard ratio [HR], 0.33 [95% CI, 0.24 to 0.45]) but significantly more vascular complications (10.3% vs 2.4%; adjusted HR, 4.42 [95% CI, 2.54 to 7.71]), conduction disturbances requiring pacemaker implantation (14.2% vs 7.3%; adjusted HR, 2.05 [95% CI, 1.43 to 2.94]), and mild (38.3% vs 11.7%) or moderate (2.3% vs 0.6%) aortic regurgitation (adjusted odds ratio for mild, moderate, or severe [no instance of severe reported] aortic regurgitation combined vs none, 4.89 [95% CI, 3.08 to 7.75]). Conclusions and Relevance: Among patients aged 70 years or older with severe, symptomatic aortic stenosis and moderately increased operative risk, TAVI was noninferior to surgery with respect to all-cause mortality at 1 year. Trial Registration: isrctn.com Identifier: ISRCTN57819173