Practical application of the geometric geoid for heighting over Nairobi county and its environs

Geoid determination is one of the main current geodetic problems in Kenya. This is because a geoid model is required to convert ellipsoidal heights to orthometric heights that are used in practice. A local geometric geoid covering Nairobi County and its environs has been determined by a geometric approach. Nineteen points levelled by both Global Positioning System (GPS) and precise levelling techniques in the area of study have been used. Seven triangulation points have been used for the determination of transformation parameters between World Geodetic System 1984 (WGS84) and Arc‐Datum 1960 coordinates in order to express the local geoid height as a function of position. The geoid height is expressed as a function of the local plane coordinates through a biquadratic surface polynomial, using 14 GPS/levelling points. Five points have been used for testing the results. The experience with Nairobi County and its environs geometric geoid indicates that interpolation of geoid heights in a small area by a biquadratic polynomial is simple and it works well. The geoid heights obtained by biquadratic polynomial (interpolation) compare favourably on the test points with root mean square and standard deviation of ±1cm in the area of study. This accuracy is sufficient for most engineering projects.Key words: Geoid, GPS, coordinate transformation, height determination, Nairobi Count

High-resolution regional gravity field recovery from Poisson wavelets using heterogeneous observational techniques

2016-2017 > Academic research: refereed > Publication in refereed journal201804_a bcmaVersion of RecordPublishe

Behavioral problems in children with epilepsy in rural Kenya. Epilepsy & Behavior

The aims of this study were to record behavioral problems in children with epilepsy (CWE), compare the prevalence with that reported among healthy children without epilepsy, and investigate the risk factors. A child behavioral questionnaire for parents comprising 15 items was administered to the main caregiver of 108 CWE and 108 controls matched for age in Kilifi, Kenya. CWE had a higher mean score for reported behavioral problems than controls (6.9 vs 4.9, t=4.7, P<0.001). CWE with active epilepsy also recorded more behavioral problems than those with inactive epilepsy (8.2 vs 6.2, t=−2.9, P=0.005). A significantly greater proportion of CWE (49% vs 26% of controls) were reported to have behavioral problems. Active epilepsy, cognitive impairment, and focal seizures were the most significant independent covariates of behavioral problems. Behavioral problems in African CWE are common and need to be taken into consideration in planning comprehensive clinical services in this region

Impaired everyday memory associated with encephalopathy of severe malaria: the role of seizures and hippocampal damage.

BACKGROUND: Seizures are common in children admitted with severe falciparum malaria and are associated with neuro-cognitive impairments. Prolonged febrile seizures are associated with hippocampal damage and impaired memory. It was hypothesized that severe malaria causes impaired everyday memory which may be associated with hippocampal damage. METHODS: An everyday memory battery was administered on 152 children with cerebral malaria (CM) (mean age, 7 y 4 months [SD 13 months]; 77 males) 156 children (mean age, 7 y 4 months [SD, 14 months]; 72 males) with malaria plus complex seizures (MS) and 179 children (mean age, 7 y 6 months [SD, 13 months]; 93 males) unexposed to either condition. RESULTS: CM was associated with poorer everyday memory [95% CI, -2.46 to -0.36, p = 0.004] but not MS [95% CI, -0.91 to 1.16, p = 1.00] compared to unexposed children. Children with exposure to CM performed more poorly in recall [95% CI, -0.79 to -0.04, p = 0.024] and recognition subtests [95% CI, -0.90 to -0.17, p = 0.001] but not in prospective memory tests compared to controls. The health factors that predicted impaired everyday memory outcome in children with exposure to CM was profound coma [95% CI, 0.02 to 0.88, p = 0.037] and multiple episodes of hypoglycaemia [95% CI, 0.05 to 0.78, p = 0.020], but not seizures. DISCUSSION: The findings show that exposure to CM was associated with a specific impairment of everyday memory. Seizures commonly observed in severe malaria may not have a causal relationship with poor outcome, but rather be associated with profound coma and repeated metabolic insults (multi-hypoglycaemia) that are strongly associated with impaired everyday memory

Infections of the Central Nervous System and Child Development in Sub-Saharan Africa

Abstract: Infectious diseases contribute significantly to child mortality in Africa; however, mortality rates only represent part of the problem. Among those who survive, cognitive, educational, and behavioral impairments have been reported. In the current chapter, I highlight the neurocognitive deficits, mental health problems, and poor educational outcomes associated with exposure to infectious diseases early in life. Special attention is paid to outcomes of HIV-infected children and children exposed to malaria. The chapter concludes by highlighting two approaches to intervention that have been observed to remediate some of the adverse effects of exposure to infections. Given the prevalence of infectious diseases in the African context, there are huge adverse effects and loss in human potential associated with childhood infectious diseases; identifying points of interventions and implementing evidence-based intervention for children infected with these conditions need to be a priority for applied developmental sciences

Mortality from esophagectomy for esophageal cancer across low, middle, and high-income countries: An international cohort study

Background: No evidence currently exists characterising global outcomes following major cancer surgery, including esophageal cancer. Therefore, this study aimed to characterise impact of high income countries (HIC) versus low and middle income countries (LMIC) on the outcomes following esophagectomy for esophageal cancer.Method: This international multi-center prospective study across 137 hospitals in 41 countries included patients who underwent an esophagectomy for esophageal cancer, with 90-day follow-up. The main explanatory variable was country income, defined according to the World Bank Data classification. The primary outcome was 90-day postoperative mortality, and secondary outcomes were composite leaks (anastomotic leak or conduit necrosis) and major complications (Clavien-Dindo Grade III-V). Multivariable generalized estimating equation models were used to produce adjusted odds ratios (ORs) and 95% confidence intervals (CI95%).Results: Between April 2018 to December 2018, 2247 patients were included. Patients from HIC were more significantly older, with higher ASA grade, and more advanced tumors. Patients from LMIC had almost three-fold increase in 90-day mortality, compared to HIC (9.4% vs 3.7%, p &lt; 0.001). On adjusted analysis, LMIC were independently associated with higher 90-day mortality (OR: 2.31, CI95%: 1.17-4.55, p = 0.015). However, LMIC were not independently associated with higher rates of anastomotic leaks (OR: 1.06, CI95%: 0.57-1.99, p = 0.9) or major complications (OR: 0.85, CI95%: 0.54-1.32, p = 0.5), compared to HIC.Conclusion: Resections in LMIC were independently associated with higher 90-day postoperative mortality, likely reflecting a failure to rescue of these patients following esophagectomy, despite similar composite anastomotic leaks and major complication rates to HIC. These findings warrant further research, to identify potential issues and solutions to improve global outcomes following esophagectomy for cancer. (C) 2020 Elsevier Ltd, BASO similar to The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved