282 research outputs found

    Study of the Geographically Weighted Regression Application on Climate Data

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    This study used Geographical Weighted Regression (GWR) technique to find spatial relationship between Elevation and climate (Rainfall, Temperature) in Northern Nigeria using climate (Rainfall, Temperature) data from weather stations from 1980 – 2010 obtained from Nigerian Meteorological Agency (Nimet). From the results of the analysis it was shown that there is significant relationship between the elevation and climate variables (Rainfall, Tmax and Tmin). The study also shows that GWR has smaller residual sum of square than OLS in analysing the relationship between Elevation and Climate data. This may be due to the consideration of the spatial variation of the relationship over the study region. When mapping the results of GWR model it was observed that the effect of Elevation on climate variables appears to vary geographically Keyword: Geographical Weighted Regression (GWR), Ordinary Least square (OLS)

    Identification of induction machine parameters using only no-load test measurements

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    Several methods have been used to estimate the parameters of induction machines. The basic method is the standard no-load and block rotor test. Although accurate results are obtained using this method; however, performing the locked rotor test is difficult, requiring full control of the voltage by using appropriate instrument to mechanically secure the rotor in the locked condition. Therefore, in this paper, a method requiring only a no-load test to extract the parameters of the induction machine is presented. The proposed method is based on the modification of the third impedance calculation of the IEEE standard 112. To validate the proposed method, parameters of a standard 7.5kW induction machine are estimated. Based on the experimental results, the maximum recorded error in the parameter estimation is less than -2.881% when compared to the reference parameters obtained from the conventional no-load and blocked rotor test.Keywords: induction motor, no-load tests, machine parameters, third impedance calculation, blocked-rotor tes

    Diagnosis of Faulty Elements in Array Antenna using Nature Inspired Cuckoo Search Algorithm

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    Detection and correction of faulty elements in a linear array have great importance in radar, sonar, mobile communications and satellite. Due to single element failure, the whole radiation pattern damage in terms of side lobes level and nulls. Once we have detect the position of defective element, then correction method is applied to achieve the desired pattern. In this work, we introduce a nature inspired meta-heuristic cuckoo search algorithm to diagnose the position of defective elements in a linear array. The nature inspired cuckoo search algorithm is new to the optimization family and is used first time for fault detection in an array antenna. Cuckoo search algorithm is a global search optimization technique. The cost function is used as a fitness function which defines an error between the degraded far field power pattern and the estimated one. The proposed technique is used effectively for the diagnosis of complete, as well as, for partial faulty elements position. Different simulation results are evaluated for 40 elements Taylor pattern to validate and check the performance of the proposed technique

    Electrical characterization of n-type cylindrical gate all around nanowire junctionless transistor with sio2 and high-k dielectrics

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    In this work, the electrical characteristics of n-type cylindrical gate all around (GAA) nanowire junctionless transistors (NWJLT) of different gate oxides are investigated and analyzed. Silicon dioxide (SiO2) and two high-k dielectrics which are silicon nitride (Si3N4) and hafnium dioxide (HfO2) were used in this study. GAANWJLT of different gate lengths (LG) and nanowire diameter (dNW) were simulated, compared and analyzed to obtain the most optimum device. SDE and Sdevice tools of Sentaurus TCAD were used to simulate and extract the electrical properties of the proposed devices. It was found that GAANWJLT with high-k dielectrics significantly exhibits better electrical properties than with SiO2 due to increase in internal fringe capacitance of the gate dielectric layer. SCEs were considerably improved as the gate-to-channel capacitance reduced. It was found that, for LG of 7 nm and dNW of 6 nm GAANWJLT, device with HfO2 exhibits better electrical properties with more than 2-fold elevated in ION/IOFF ratio and about 15% improvement in SS than the conventional device with SiO2. It proves that GAANWJLT with HfO2 exhibits the most optimum electrical characteristics among the three devices, hence the best alternative to improve SCEs as well as to increase the switching speed of the transistor devices

    A Clinicopathological Review of Colonic Polyps in a Tertiary Hospital in North Central Nigeria

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    Background: Colorectal polyps, especially adenomas, are known as precursors of colorectal carcinomas. This study was aimed at determining the prevalence and histopathologic characteristics of colonic polyps among Nigerians that underwent colonoscopy at the University of Ilorin Teaching Hospital, Ilorin, Nigeria. The authors also determined the polyp detection rate and adenoma detection rate. Materials and Methods: This was a hospital-based cross-sectional study of all colonoscopy examinations performed at the University of Ilorin Teaching Hospital, Ilorin from March 2013 to September 2017. The endoscopy register was reviewed, and patients’ biodata, indications for colonoscopy and colonoscopic findings were recorded on a proforma. The histopathologic reports of the polyps were also retrieved and their diagnosis confirmed. Results: A total of 289 patients had colonoscopy carried out on them. The age of the patients ranged from 14 to 90 years with a mean ±SD of 57.0 ± 15.3 years and a median age of 58 years. There were 178 (61.6%) males and 111 (38.4%) females giving a M:F ratio of 1.6:1. The indications for colonoscopy were rectalbleeding 124 (42.9%); suspected colorectal cancer 67 (23.2%); abdominal pain 22 (7.6%); chronic diarrhea 18 (6.2%); surveillance colonoscopy 12 (4.2%); constipation 11 (3.8%); change in bowel habit 9 (3.1%); occult bleeding 6 (2.1%); others 20 (6.9%). Endoscopic findings were normal findings 89 (30.8%); hemorrhoids 88 (30.4%); colonic polyps 50 (17.3%); diverticulosis 34 (11.8%); rectal cancer 29 (10.0%); colon cancer 24 (8.3%); colitis 19 (6.6%); others 13 (4.5%). The findings were not mutually exclusive. The diagnostic yield was 69.2%. The overall polyp detection rate was 17.3%. Of the 50 patients with polyps, 33 (66.0%) were males (p = 0.481). Theadenoma detection rate was 4.8%. Conclusion: The authors conclude that their observed polyp detection rate is consistent with the estimated rates for Africa. Rectal bleeding and adenomatous polyps were the commonest presentation and histopathologic finding, respectively

    Promotion of Zinc Tablets with ORS through Child Health Weeks Improves Caregiver Knowledge, Attitudes, and Practice on Treatment of Diarrhoea in Nigeria

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    We examined whether the Maternal, Newborn and Child Health Weeks (MNCHW) in Nigeria would present an opportunity to raise awareness of and demand for the use of zinc and ORS in the treatment for diarrhoea, guided by a conceptual framework designed to assess three theoretical underpinnings (characteristics and performance standard of the health workers, potential reach, and intensity of the intervention), along the impact pathway. Zinc and ORS with education for their appropriate use during the next diarrhoeal episode were delivered as part of the November 2010 and May 2011 MNCHW. On the day of but before participating in MNCHW activities, semi-structured interviews were used for collecting information on knowledge, attitudes, and practice (KAP) relating to diarrhoea from 602 caregivers with children aged less than five years. Forty-eight health workers were also interviewed. Nearly all health workers (98%) correctly mentioned the dosage of zinc while only 58% correctly stated the preparation of ORS. The proportion of caregivers with knowledge on the treatment for diarrhoea increased from 46.4% in November 2010 pre-MNCHW to 71.3% in May 2011 pre-MNCHW interviews (p<0.001). More caregivers correctly mentioned the dosage of zinc (80.9%) and stated the preparation of ORS (88.8%) in the November 2010 exit interview immediately after the MNCHW encounter compared to the levels a few months later in the home follow-up visit (53.1% and 37.4% respectively). After attending both rounds of November 2010 and May 2011 MNCHW, caregivers\u2019 knowledge on the treatment of diarrhoea increased seven times compared to the caregivers who attended the May 2011 MNCHW only (OR=7.0, p<0.001). Additionally, caregivers were 40% less likely to seek advice outside the home in the treatment for diarrhoea if they had attended both the MNCHWs than if they had attended the May 2011 MNCHW only (OR=0.6, p<0.029). We conclude that providing opportunities for caregivers to receive a sample of zinc and ORS and to learn about its use in the treatment for diarrhoea, from trained health workers during MNCHW, has the potential to increase KAP relating to the use of zinc and ORS in the treatment for diarrhoea and for future diarrhoeal episodes

    Evaluation of a DSGE Model of Energy in the United Kingdom Using Stationary Data

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    I examine the impact of energy price shock (oil prices shock and gas prices shock) on the economic activities in the United Kingdom using a dynamic stochastic general equilibrium model with a New Keynesian Philips Curve. I decomposed the changes in output caused by all of the stationary structural shocks. I found that the fall in output during the financial crisis period is driven by domestic demand shock, energy prices shock and world demand shock. I found the energy prices shock’s contribution to fall in output is temporary. Such that, the UK can borrow against such a temporary fall. This estimated model can create additional input to the policymaker’s choice of models

    Availability and prioritisation of COVID-19 vaccines among patients with advanced chronic kidney disease and kidney failure during the height of the pandemic: a global survey by the International Society of Nephrology

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    OBJECTIVE Patients with advanced chronic kidney disease (CKD) or kidney failure receiving replacement therapy (KFRT) are highly vulnerable to COVID-19 infection, morbidity and mortality. Vaccination is effective, but access differs around the world. We aimed to ascertain the availability, readiness and prioritisation of COVID-19 vaccines for this group of patients globally. SETTING AND PARTICIPANTS Collaborators from the International Society of Nephrology (ISN), Dialysis Outcomes and Practice Patterns Study and ISN-Global Kidney Health Atlas developed an online survey that was administered electronically to key nephrology leaders in 174 countries between 2 July and 4 August 2021. RESULTS Survey responses were received from 99 of 174 countries from all 10 ISN regions, among which 88/174 (50%) were complete. At least one vaccine was available in 96/99 (97%) countries. In 71% of the countries surveyed, patients on dialysis were prioritised for vaccination, followed by patients living with a kidney transplant (KT) (62%) and stage 4/5 CKD (51%). Healthcare workers were the most common high priority group for vaccination. At least 50% of patients receiving in-centre haemodialysis, peritoneal dialysis or KT were estimated to have completed vaccination at the time of the survey in 55%, 64% and 51% of countries, respectively. At least 50% of patients in all three patient groups had been vaccinated in >70% of high-income countries and in 100% of respondent countries in Western Europe.The most common barriers to vaccination of patients were vaccine hesitancy (74%), vaccine shortages (61%) and mass vaccine distribution challenges (48%). These were reported more in low-income and lower middle-income countries compared with high-income countries. CONCLUSION Patients with advanced CKD or KFRT were prioritised in COVID-19 vaccination in most countries. Multiple barriers led to substantial variability in the successful achievement of COVID-19 vaccination across the world, with high-income countries achieving the most access and success

    Persistent hypertension up to one year postpartum among women with hypertensive disorders in pregnancy in a low-resource setting:A prospective cohort study

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    BACKGROUND: Hypertensive disorders in pregnancy (HDPs) are associated with lifelong cardiovascular disease risk. Persistent postpartum hypertension in HDPs could suggest progression to chronic hypertension. This phenomenon has not been well examined in low- and middle-income countries (LIMCs), and most previous follow-ups typically last for maximally six weeks postpartum. We assessed the prevalence of persistent hypertension up to one year in women with HDPs in a low resource setting and determined associated risk factors. METHODOLOGY: A prospective cohort study of women conducted at eight tertiary health care facilities in seven states of Nigeria. Four hundred and ten women with any HDP were enrolled within 24 hours of delivery and followed up at intervals until one year postpartum. Descriptive statistics were performed to express the participants’ characteristics. Univariable and multivariable logistic regressions were conducted to identify associated risk factors. RESULTS: Of the 410 women enrolled, 278 were followed up to one year after delivery (follow-up rate 68%). Among women diagnosed with gestational hypertension and pre-eclampsia/eclampsia, 22.3% (95% CI; 8.3–36.3) and 62.1% (95% CI; 52.5–71.9), respectively, had persistent hypertension at six months and this remained similar at one year 22.3% (95% CI; 5.6–54.4) and 61.2% (95% CI; 40.6–77.8). Maternal age and body mass index were significant risk factors for persistent hypertension at one year [aORs = 1.07/year (95% CI; 1.02–1.13) and 1.06/kg/m(2) (95% CI; 1.01–1.10)], respectively. CONCLUSION: This study showed a substantial prevalence of persistent hypertension beyond puerperium. Health systems in LMICs need to be organized to anticipate and maintain postpartum monitoring until blood pressure is normalized, or women referred or discharged to family physicians as appropriate. In particular, attention should be given to women who are obese, and or of higher maternal age

    Metabolic syndrome following hypertensive disorders in pregnancy in a low-resource setting:A cohort study

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    Objectives: Hypertensive disorders in pregnancy (HDPs) are associated with risk of future metabolic syndrome. Despite the huge burden of HDPs in sub-Saharan Africa, this association has not been adequately studied in this population. Study design: This was a prospective cohort study on pregnant women recruited between August 2017 - April 2018 and followed up to one year after their deliveries and evaluated for presence of metabolic syndrome at delivery, nine weeks, six months and one year. Main outcome measures: Prevalence of metabolic syndrome Results: A total of 488 pregnant women were included: 410 and 78 with HDPs and normotensive, respectively. None of the normotensive had metabolic syndrome until one year (1.7% = 1 out of 59 observations), while among those with HDPs were 17.4% (71 of 407), 8.7% (23 of 263), 4.7% (11 of 232) and 6.1% (17 of 278), at delivery, nine weeks, six months and one year postpartum, respectively. High BMI and blood pressure were the drivers of metabolic syndrome in this population. The incidence rate in HDPs versus normotensive at one year were, respectively, 57.5/1000 persons’ year (95%CI; 35.8 – 92.6) and 16.9/1000 persons’ years (95%CI; 2.4-118.3), with incidence rate ratio of 3.4/1000 person's years. Only parity significantly predicted the presence of metabolic syndrome at one year [(aOR= 3.26/delivery (95%CI; 1.21-8.79)]. Conclusion: HDPs were associated with a higher incidence of metabolic syndrome up to one year postpartum. Women with HDPs should be routinely screened for metabolic syndrome within the first year postpartum to reduce cardiometabolic risks.</p
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