Numerical Computation of the Complex Eigenvalues of a Matrix by solving a Square System of Equations

It is well known that if the largest or smallest eigenvalue of a matrix has been computed by some numerical algorithms and one is interested in computing the corresponding eigenvector, one method that is known to give such good approximations to the eigenvector is inverse iteration with a shift. For complex eigenpairs, instead of using Ruhe’s normalization, we show that the natural two norm normalization for the matrix pencil, yields an underdetermined system of equation and by adding an extra equation, the augmented system becomes square which can be solved by LU factorization at a cheaper rate and quadratic convergence is guaranteed. While the underdetermined system of equations can be solved using QR factorization as shown in an earlier work by the same authors, converting it to a square system of equations has the added advantage that besides using LU factorization, it can be solved by several approaches including iterative methods. We show both theoretically and numerically that both algorithms are equivalent in the absence of roundoff errors

AI powered social commerce technology and customer experience: A systematic literature review

Over the last 3 decades, the digital revolution has drastically transformed customer/user experience. Negroponte (1995) described this transformation as a shift from atoms to bits. Schmitt (2019) supported that, in the context of marketing atoms are fast moving consumer goods and their brands, made in factories, advertised through mass media, and sold in stores; bits are information, entertainment and interactive products, often produced instantaneously, promoted through social media and sold online. Artificial Intelligence (AI) powered technologies such as social commerce, Internet of things (IoT), Augmented reality (AR), Virtual Reality (VR), Smart technology, or digital payments technologies have the potential to revolutionize customer or user experience. Artificial intelligence (AI) is reshaping business, economy, and society by transforming consumers experiences and relationships amongst stakeholders and citizens (Loureiro, Guerreiro and Tussyadiah, 2020).info:eu-repo/semantics/acceptedVersio

Web-Based Advanced Traveller Information System for Minna Metropolis, Nigeria

Advanced Traveller Information System (ATIS) is used to provide accurate, integrated and comprehensive travel and traffic information to road users. The information helps in both pre-trip and en-route decision making. This study developed a web-based ATIS for Minna metropolis in Nigeria. The information provided is from both primary and secondary sources. The developed ATIS provides information on route guidance, available intercity transport services and hotels in the metropolis. It also allows users to determine both weather and traffic flow conditions. A component of the system makes provision for electronic fare payment and booking of trips and hotel accommodation. The deployment of the ATIS is a source of static and dynamic information

ABH secretor status of students in the college of medical sciences, University of Maiduguri by inhibition method

Background: ABH blood group and secretor status of individuals are inherited independently although both may be associated with diabetes, autoimmune diseases and heart diseases. Aim: A cross-sectional study was employed to determine the ABH blood group and secretor status of students in the University of Maiduguri. Methodology: Two ml blood and 3ml saliva were collected from each study participants and were assayed independently. The ABO blood group and secretor status were determined by tube method and haemagglutination inhibition technique respectively. Results: A total of 235 apparently healthy students of the College of Medical Sciences participated in this study. Of the 235 participants, 97.4% are ABH secretors whereas 2.6% are ABH non-secretors. One hundred and nineteen 119(50.6%) of the subjects are males, of which 115 are secretors while 4 are non-secretors. Among the 116(49.4%) females who participated, 114 are secretors while 2 are non-secretors. The distribution of ABO blood group among the subjects shows that 21.3% were group A, 20.8% group B, 8.5% group AB and 49.4% group O. Conclusion: In this study, Blood group O is the commonest while AB was the least among the subjects. Overall, there are more secretors than non-secretors among the subjects. However, the study suggests that the ability to secrete ABH substances is independent of ABO blood group genes. The analysis also helps in revealing the prevalence of secretor status among the students. With the associations of disease and secretors, the secretor status of individuals may play a role in the diagnosis and management of diseases. Keywords: ABO blood group; secretor status; ABH antigen

Cross-sectional study of antioxidant status in normotensive and hypertensive pregnancy

Objectives: The study measured the concentrations of antioxidants in women during pregnancy and the Post Partum Period (PPP) with a view to investigating their role in the aetiology of pregnancy induced hypertension (PIH). Study Design: Informed consent was obtained from 105 women who were divided into three groups: 15 age and parity matched normotensive non-pregnant (control group), 45 normotensive and 45 hypertensive pregnant women. The two groups of pregnant women were divided into three groups of 15 each and studied in the second and third trimesters and PPP respectively. Venous blood was obtained from all the participants for measurements of some antioxidants (uric acid, albumin, catalase and vitamin C). Data were analyzed using descriptive and inferential statistical methods. Results: The results show that the mean concentrations of catalase, albumin, vitamin C and uric acid for the control were 3.1 ± 0.18 µ/l, 46.6 ± 6.6 g/l, 0.38 ± 0.01 mg/dl and 0.16 ± 0.03 mmol/l respectively. The mean concentration of all antioxidants except uric acid were significantly lower during pregnancy when compared with controls (t= 2.06; p<0.01). In the normotensive group of pregnant women, vitamin C was the only antioxidant that showed significant higher concentration when the second trimester concentration and third trimester concentration were compared (t=2.06; p<0.05). Uric acid levels were significantly higher (t=2.06; p<0.05) and nd rd catalase and vitamin C levels were significantly lower in the hypertensive group during the 2 and 3 trimesters (t=2.06; p<0.05). There was a tendency for all antioxidant concentrations to return to normal values during the PPPin the normotensive group; however in the hypertensive group, uric acid levels remained significantly higher (t=2.06; p<0.05). Conclusion: In conclusion this study showed that pregnancy generally reduced the concentration of antioxidants but vitamin C levels were higher in late pregnancy of normotensive women. Therefore higher levels of vitamin C may protect against PIH

Substance Use: Prevalence, Pattern and Risk Factors among Undergraduate Students in a Tertiary Institution in Southwest Nigeria

Background: Substance use is a global public health problem with increasing burden among university students. This study assessed the prevalence, pattern and risk factors of substance use among undergraduate students of Afe Babalola University, Ado-Ekiti, Nigeria.Methods: This was a cross-sectional study of undergraduate students of Afe Babalola University, Ado-Ekiti. A multi-stage sampling technique was used to select respondents. Data collection tool was a structured self-administered questionnaire. Data analysis was done using Statistical Package for the Social Sciences (SPSS) version 23. Statistical significance was set at p value &lt;0.05Results: The respondents’ mean age was 19.5 ± 2.0 years and all 416 (100.0%) were aware of substance abuse. The prevalence of substance use was 299 (71.9%). Alcohol 133 (32.0%) and over-the-counter drugs (29.9%) were the two most commonly used substance. Being male (p=0.017) and in 400 level (p=0.047) were associated with substance use while curiosity 112 (37.5%), peer pressure 95 (31.8%) and school stress 85 (28.4%) were reasons given. Predictors of substance use were being a female (aOR: 2.54; 95% CI=1.89-3.66; p=0.011), civil servant mother (aOR: 5.75; 95% CI=1.90-17.4; p=0.002) and mother with secondary education (aOR: 5.27; 95% CI= 2.20- 12.65; p&lt;0.001).Conclusion: There was high prevalence of substance use with curiosity, peer pressure and school stress being influencers of substance use among the study population. Predictors of substance use were being a female, civil servant mother and mother with secondary education. The University authority should institute measures to prevent access to alcohol and other substances by the students

Evaluation of blood reservation and use for caesarean sections in a tertiary maternity unit in south western Nigeria

<p>Abstract</p> <p>Background</p> <p>Haemorrhage from obstetric causes is the most common cause of maternal mortality in the developing world. Prevention of mortality from haemorrhage will necessarily involve prompt blood transfusions among other life saving measures. There are however limited stocks of fresh or stored blood in many health care facilities in Sub Saharan Africa. Caesarean section has been identified as a common indication for blood transfusion in obstetrics practice and its performance is often delayed by non availability of blood in our centre. An evaluation of blood reservation and use at caesarean sections in a tertiary maternity unit in Lagos, south western Nigeria should therefore assist in formulating the most rational blood transfusion policies.</p> <p>Methods</p> <p>Case records of 327 patients who had elective and emergency caesarian sections at the Lagos State University Teaching Hospital between 1^stOctober and 31^stDecember 2007 were reviewed. Data pertaining to age, parity, booking status, type and indication for Caesarean section, pre- and post-operative packed cell volume, blood loss at surgery, units of blood reserved in the blood bank, unit(s) of blood transfused and duration of hospital stay was extracted and the data analysed.</p> <p>Results</p> <p>There were 1056 deliveries out of which 327 (31%) were by Caesarean section. During the study period, a total of 654 units of blood were reserved in the blood bank and subsequently made available in theatre. Out of this number, only 89 (13.6%) were transfused to 41 patients. Amongst those transfused, twenty-six (54%) were booked and 31 (75.6%) had primary caesarian section. About 81% of those transfused had emergency caesarean section. The most common indication for surgery among those transfused were placenta praevia (9 patients with 21 units of blood) and cephalo-pelvic disproportion (8 patients with 13 units).</p> <p>Conclusion</p> <p>Even though a large number of units of blood was reserved and made available in the theatre at the time of operation, majority of the patients operated did not need blood transfusion. Provision of a mini- blood bank within the obstetric unit and careful patient categorization will ensure timely availability of blood for surgery without necessarily tying down stock in the central blood bank.</p

Measuring universal health coverage based on an index of effective coverage of health services in 204 countries and territories, 1990–2019 : a systematic analysis for the Global Burden of Disease Study 2019

Background: Achieving universal health coverage (UHC) involves all people receiving the health services they need, of high quality, without experiencing financial hardship. Making progress towards UHC is a policy priority for both countries and global institutions, as highlighted by the agenda of the UN Sustainable Development Goals (SDGs) and WHO's Thirteenth General Programme of Work (GPW13). Measuring effective coverage at the health-system level is important for understanding whether health services are aligned with countries' health profiles and are of sufficient quality to produce health gains for populations of all ages. Methods: Based on the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019, we assessed UHC effective coverage for 204 countries and territories from 1990 to 2019. Drawing from a measurement framework developed through WHO's GPW13 consultation, we mapped 23 effective coverage indicators to a matrix representing health service types (eg, promotion, prevention, and treatment) and five population-age groups spanning from reproductive and newborn to older adults (>= 65 years). Effective coverage indicators were based on intervention coverage or outcome-based measures such as mortality-to-incidence ratios to approximate access to quality care; outcome-based measures were transformed to values on a scale of 0-100 based on the 2.5th and 97.5th percentile of location-year values. We constructed the UHC effective coverage index by weighting each effective coverage indicator relative to its associated potential health gains, as measured by disability-adjusted life-years for each location-year and population-age group. For three tests of validity (content, known-groups, and convergent), UHC effective coverage index performance was generally better than that of other UHC service coverage indices from WHO (ie, the current metric for SDG indicator 3.8.1 on UHC service coverage), the World Bank, and GBD 2017. We quantified frontiers of UHC effective coverage performance on the basis of pooled health spending per capita, representing UHC effective coverage index levels achieved in 2019 relative to country-level government health spending, prepaid private expenditures, and development assistance for health. To assess current trajectories towards the GPW13 UHC billion target-1 billion more people benefiting from UHC by 2023-we estimated additional population equivalents with UHC effective coverage from 2018 to 2023. Findings: Globally, performance on the UHC effective coverage index improved from 45.8 (95% uncertainty interval 44.2-47.5) in 1990 to 60.3 (58.7-61.9) in 2019, yet country-level UHC effective coverage in 2019 still spanned from 95 or higher in Japan and Iceland to lower than 25 in Somalia and the Central African Republic. Since 2010, sub-Saharan Africa showed accelerated gains on the UHC effective coverage index (at an average increase of 2.6% [1.9-3.3] per year up to 2019); by contrast, most other GBD super-regions had slowed rates of progress in 2010-2019 relative to 1990-2010. Many countries showed lagging performance on effective coverage indicators for non-communicable diseases relative to those for communicable diseases and maternal and child health, despite non-communicable diseases accounting for a greater proportion of potential health gains in 2019, suggesting that many health systems are not keeping pace with the rising non-communicable disease burden and associated population health needs. In 2019, the UHC effective coverage index was associated with pooled health spending per capita (r=0.79), although countries across the development spectrum had much lower UHC effective coverage than is potentially achievable relative to their health spending. Under maximum efficiency of translating health spending into UHC effective coverage performance, countries would need to reach $1398 pooled health spending per capita (US$ adjusted for purchasing power parity) in order to achieve 80 on the UHC effective coverage index. From 2018 to 2023, an estimated 388.9 million (358.6-421.3) more population equivalents would have UHC effective coverage, falling well short of the GPW13 target of 1 billion more people benefiting from UHC during this time. Current projections point to an estimated 3.1 billion (3.0-3.2) population equivalents still lacking UHC effective coverage in 2023, with nearly a third (968.1 million [903.5-1040.3]) residing in south Asia. Interpretation: The present study demonstrates the utility of measuring effective coverage and its role in supporting improved health outcomes for all people-the ultimate goal of UHC and its achievement. Global ambitions to accelerate progress on UHC service coverage are increasingly unlikely unless concerted action on non-communicable diseases occurs and countries can better translate health spending into improved performance. Focusing on effective coverage and accounting for the world's evolving health needs lays the groundwork for better understanding how close-or how far-all populations are in benefiting from UHC

The global burden of adolescent and young adult cancer in 2019: a systematic analysis for the Global Burden of Disease Study 2019

Background: In estimating the global burden of cancer, adolescents and young adults with cancer are often overlooked, despite being a distinct subgroup with unique epidemiology, clinical care needs, and societal impact. Comprehensive estimates of the global cancer burden in adolescents and young adults (aged 15–39 years) are lacking. To address this gap, we analysed results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019, with a focus on the outcome of disability-adjusted life-years (DALYs), to inform global cancer control measures in adolescents and young adults. Methods: Using the GBD 2019 methodology, international mortality data were collected from vital registration systems, verbal autopsies, and population-based cancer registry inputs modelled with mortality-to-incidence ratios (MIRs). Incidence was computed with mortality estimates and corresponding MIRs. Prevalence estimates were calculated using modelled survival and multiplied by disability weights to obtain years lived with disability (YLDs). Years of life lost (YLLs) were calculated as age-specific cancer deaths multiplied by the standard life expectancy at the age of death. The main outcome was DALYs (the sum of YLLs and YLDs). Estimates were presented globally and by Socio-demographic Index (SDI) quintiles (countries ranked and divided into five equal SDI groups), and all estimates were presented with corresponding 95% uncertainty intervals (UIs). For this analysis, we used the age range of 15–39 years to define adolescents and young adults. Findings: There were 1·19 million (95% UI 1·11–1·28) incident cancer cases and 396 000 (370 000–425 000) deaths due to cancer among people aged 15–39 years worldwide in 2019. The highest age-standardised incidence rates occurred in high SDI (59·6 [54·5–65·7] per 100 000 person-years) and high-middle SDI countries (53·2 [48·8–57·9] per 100 000 person-years), while the highest age-standardised mortality rates were in low-middle SDI (14·2 [12·9–15·6] per 100 000 person-years) and middle SDI (13·6 [12·6–14·8] per 100 000 person-years) countries. In 2019, adolescent and young adult cancers contributed 23·5 million (21·9–25·2) DALYs to the global burden of disease, of which 2·7% (1·9–3·6) came from YLDs and 97·3% (96·4–98·1) from YLLs. Cancer was the fourth leading cause of death and tenth leading cause of DALYs in adolescents and young adults globally. Interpretation: Adolescent and young adult cancers contributed substantially to the overall adolescent and young adult disease burden globally in 2019. These results provide new insights into the distribution and magnitude of the adolescent and young adult cancer burden around the world. With notable differences observed across SDI settings, these estimates can inform global and country-level cancer control efforts. Funding: Bill &amp; Melinda Gates Foundation, American Lebanese Syrian Associated Charities, St Baldrick's Foundation, and the National Cancer Institute

Mapping inequalities in exclusive breastfeeding in low- and middle-income countries, 2000–2018

Abstract: Exclusive breastfeeding (EBF)—giving infants only breast-milk for the first 6 months of life—is a component of optimal breastfeeding practices effective in preventing child morbidity and mortality. EBF practices are known to vary by population and comparable subnational estimates of prevalence and progress across low- and middle-income countries (LMICs) are required for planning policy and interventions. Here we present a geospatial analysis of EBF prevalence estimates from 2000 to 2018 across 94 LMICs mapped to policy-relevant administrative units (for example, districts), quantify subnational inequalities and their changes over time, and estimate probabilities of meeting the World Health Organization’s Global Nutrition Target (WHO GNT) of ≥70% EBF prevalence by 2030. While six LMICs are projected to meet the WHO GNT of ≥70% EBF prevalence at a national scale, only three are predicted to meet the target in all their district-level units by 2030