172 research outputs found
Genotype x environment interaction and stability analyses of yield of upland cotton (Gossypium hirsutum L.) in central Sudan
Seed cotton yield stability of genotype over environments is a useful parameter for recommending cultivars for known cropping conditions. Fifteen upland cotton inbred lines and the check (commercial cultivar Hamid were evaluated. over two consecutive seasons (2013/14 and 2014/15) at three locations, Rahad, Gezira and Sennar Research Station of the Agricultural Research Corporation, Sudan. A randomized complete block design with four replicates was used. The objective was to assess the genotype by environment interaction and stability of seed cotton yield. The mean squares due to environment were significant while genotype and genotype x environment interaction were highly significant for seed cotton yield. Significant differences among genotypes for the studied characters were found in almost all seasons, indicating that these cotton genotypes were highly variable for the characters studied and, therefore, expected to respond to selection. The interaction effects of genotype x location were significant for all traits indicating that genotypes responded differently to different environments. Statistical models of stability analysis, i.e. Eberhart and Russel model as well as the additive main effect and multiplicative interaction (AMMI), indicated that genotypes RS-5, R-96, R-231, R-43 and R-1 revealed good stability and high seed cotton yields across environments. In conclusion, and based on stability parameters, genotypes R-6, R-40, R-231, and R-43 are recommended for further testing over a range of environments to examine their yield stability and suitability for large field production.
يعتبر ثبات الانتاجية للقطن الزهرة من أفضل الطرق للتوصية بزراعة الاصناف حسب الظروف المحصولية لكل صنف. تم اختبار 15 سلالة نقية من القطن الأكالا (Gossypium hirsutum L.) بالأضافة الي الصنف حامد المنزرع تجاريا بالسودان في موسمي 14/2013 و 15/2014 في محطة بحوث الرهد و محطة بحوث الجزيرة و محطة بحوث سنار, هيئة البحوث الزراعية (ARC), السودان. استخدم تصميم القطاعات العشوائية الكاملة بأربعة مكررات. هدفت الدراسة لتقويم التفاعل الوراثي والبيئ وثبات درجة انتاجية القطن زهرة. أظهرتحليل التباين فروقات معنوية مع البيئات بينما أظهرت السلالات وتفاعل السلالات مع البيئات لانتاجية القطن زهره فروقات معنوية عالية. أيضا أظهرة الدراسة فروقات معنوية لمعظم الصفات التي درسة في كل موسم, وهذا يشير الي وجود فروقات عالية بين سلالات القطن التي درست, عليه يمكنها الاستجابة للانتخاب. أوضح التحليل الاحصائي ل Eberhart and Russel model (1966) و (AMMI) أن الطرز RS-5 و R-96 و R-231 وR-43 و R-1 أظهرت درجة ثبات وانتاجية عالية في كل البيئات. خلاصة البحث واستناداً علي متوسط الأداء وثبات الانتاجية يوصى باختبار ثبات انتاجية الطرز الوراثية R-6 وR-40 و R-231و R-43 في عدة مواقع ومواسم للتأكد من نتائج هذه الدراسة والاستفادة منها في توصية باجازة بعض هذه الطرز لتناسب الظروف البيئية في السودا
Evaluation of stochastic optimisation algorithms for induction machine winding fault identification
PhD ThesisThis thesis is concerned with parameters identification and winding fault detection in induction motors using three different stochastic optimisation algorithms, namely genetic algorithm (GA), tabu search (TS) and simulated annealing (SA).
Although induction motors are highly reliable, require low maintenance and have relatively high efficiency, they are subject to many electrical and mechanical types of faults. Undetected faults can lead to serious machine failures. Fault identification is, therefore, essential in order to detect and diagnose potential failures in electrical motors. Conventional methods of fault detection usually involve embedding sensors in the machines, but these are very expensive. The condition monitoring technique proposed in this thesis flags the presence of a winding fault and provides information about its nature and location by using an optimisation stochastic algorithm in conjunction with measured time domain voltage, stator current data and rotor speed data. This technique requires a mathematical ABCabc model of the three-phase induction motor.
The performance of the three stochastic search methods is evaluated in this thesis for their use to identify open-circuit faults in the stator and rotor windings of a three-phase induction motor. The proposed fault detection technique is validated through the use of experimental data collected under steady-state operating conditions.
Time domain terminal voltages and the rotor speed are used as input data for the induction motor model while the outputs are the calculated stator currents. These calculated currents are compared to the measured currents to produce a set of current errors that are integrated and summed to give an overall error function. Fault identification is achieved by adjusting the model parameters off-line using the stochastic search method to minimise this error function. The estimate values for the winding parameters give the best possible match between the performance of the faulty experimental machine and its mathematical ABCabc model. These estimates of the values of the motor winding parameters are used in the detection of the development of faults by identifying both the location and the nature of the winding fault. The effectiveness of the three stochastic methods to identify stator and rotor winding faults are compared in terms of the required computation resources and their success rates in converging to a solution.Ministry of Higher Education of Libyan Government
Vertical transmission of hepatitis C virus: systematic review and meta-analysis.
BACKGROUND: We conducted a systematic review of estimates of hepatitis C virus (HCV) vertical transmission risk to update current estimates published more than a decade ago. METHODS: PubMed and Embase were searched and 109 articles were included. Pooled estimates of risk were generated for children born to HCV antibody-positive and viremic women, aged ≥18 months, separately by maternal human immunodeficiency virus (HIV) coinfection. RESULTS: Meta-analysis of the risk of vertical HCV infection to children of HCV antibody-positive and RNA-positive women was 5.8% (95% confidence interval [CI], 4.2%-7.8%) for children of HIV-negative women and 10.8% (95% CI, 7.6%-15.2%) for children of HIV-positive women. The adjusted meta-regression model explained 51% of the between-study variation in the 25 included risk estimates. Maternal HIV coinfection was the most important determinant of vertical transmission risk (adjusted odds ratio, 2.56 [95% CI, 1.50-4.43]). Additional methodological (follow-up rate and definition of infection in children) and risk factors independently predicted HCV infection and need to be captured and reported by future studies of vertical transmission. Studies assessing the contribution of nonvertical exposures in early childhood to HCV prevalence among children at risk of vertical transmission are needed. CONCLUSIONS: More than 1 in every 20 children delivered by HCV chronically infected women are infected, highlighting that vertical transmission likely constitutes the primary transmission route among children. These updated estimates are a basis for decision making in prioritization of research into risk-reducing measures, and inform case management in clinical settings, especially for HIV-positive women in reproductive age
Rethinking (local) integration:Domains of integration and their durability in Kismayo and Garowe, Somalia
Amidst the ever-expanding debates in various academic and policy fields around migrant and refugee integration and local integration, we bring these two concepts in conversation with one another. Until very recently, theories of integration have had a state-centric focus in the Global North. This article expands and complicates this literature to focus on displaced Somalis within Somalia and its borderlands living in the cities of Kismayo and Garowe using mixed qualitative and quantitative methods in five displacement settlements. Toward this end, we use the often- engaged term “domains of integration” to frame integration. In our conceptualization, however, we incorporate the concept of “local integration” as a durable solution. In brief, we see the domains of integration as a productive concept in the Somali context. However, in Somalia, where clans are interwoven into the state, which lacks resources and power, clan affiliation represents social connections domains, yet also influences the state's role in the foundational domain of rights and citizenship and makers and means (employment, housing, education, health). International donors and NGOs, as well as international capitalist urban expansion also have a large role in these processes. As such, we argue that the ten domains of integration (discussed in detail below) intersect and blur to an even greater extent than in European and North American contexts, particularly around crucial issues such as housing, land, and property; a key factor in people's decisions to remain or leave.</p
Informal economies, conflict recovery and absent aid
This paper addresses the issue of what happens in the aftermath of conflict when humanitarian response is absent, to see how ‘self-help’ recovery can inform development assistance paradigms and practice. We explore livelihoods strategies and community-led recovery processes in the context of conflict in Somaliland, a region that experienced an acutely disruptive conflict and an absence of humanitarian aid, to evaluate the economic recovery that emerged. The conflict is tracked through perceptions and recollections of those who lived through the disaster: the bombing of Hargeisa in 1988 that flattened the city, the declaration of a semi-autonomous nation in 1991, and its subsequent development over the last 25 years. This critical case study aims to inform the humanitarian assistance agenda in relation to livelihoods as self-help process in post-conflict recovery
The knowledge and perceptions regarding the role of family physicians among patients in primary care clinics in Nairobi
Corrigendum to “Critical Review on Nanofluids: Preparation, Characterization, and Applications”
Pathways to care:IDPs seeking health support and justice for sexual and gender-based violence through social connections in Garowe and Kismayo, Somalia and South Kivu, DRC
A growing literature documents the significant barriers to accessing care that Internally Displaced Persons (IDPs) face. This study focuses on gender-based violence (SGBV), an issue often exacerbated in times of forced displacement, and adds to extant debates by considering the wide range of social connections (pathways and actors) involved in providing care beyond the formal biomedical (and justice) system. This research asks, who do IDPs turn to following SGBV and why? How effective do IDPs perceive these social connections to be? To answer these research questions, the study used ‘participatory social mapping’ methodology for 31 workshops held with over 200 participants in Somalia and the Democratic Republic of the Congo in 2021/2022. Pathways to SGBV-related care for IDPs appear eclectic and contingent upon not only the availability and accessibility of support resources but also social, cultural and gendered beliefs and practices. ‘Physical’, mental health, and justice needs are intertwined. They are hard to decouple as many actors cut across need categories, including family, faith and aid organisations, and customary institutions. Comparing Congolese and Somali sites of displaced communities, we see significant similarities and overlaps in pathways to care. While both countries have experienced severe erosions of state capacity, NGOs and parallel faith-based and customary legal, psychological, and health systems have filled the state's weakness to varying degrees of acceptance by IDP participants. A comprehensive understanding of the local milieu, which requires illuminating the logics behind where people actually turn to for care, is crucial for interventions supporting SGBV victims/survivors; indeed, they risk being inefficient if they only address barriers to formal systems
Protocol for a systematic review and meta-analysis of hepatitis C virus (HCV) prevalence and incidence in the Horn of Africa sub-region of the Middle East and North Africa.
BACKGROUND: In the Middle East and North Africa (MENA), hepatitis C virus (HCV) distribution appears to present a wide range of prevalence. The scale and nature of HCV disease burden is poorly known in the Horn of Africa sub-region of MENA including Djibouti, Somalia, and Sudan in addition to Yemen at the southwest corner of the Arabian Peninsula. The aim of this review is to provide a systematic review and synthesis of all epidemiological data on HCV prevalence and incidence among the different population groups in this sub-region of MENA. A second aim of the study is to estimate the national population-level HCV prevalence for each of these four countries. METHODS/DESIGN: The systematic review will be conducted based on the items outlined in the PRISMA statement. PubMed, Embase, and the World Health organization (WHO) regional databases will be searched for eligible studies without language or date restrictions. Observational and intervention studies reporting data on the prevalence or incidence of HCV in any population group in Djibouti, Somalia, Sudan, or Yemen will be included. Additional sources will be obtained through the database of the MENA HIV/AIDS Epidemiology Synthesis Project, including international organizations' reports and country-level reports, and abstracts of international conferences. Study and population characteristics will be extracted from eligible publications, with previously agreed pro formas; and entered into a computerized database. We will pool prevalence using DerSimonian and Laird random-effects models after a Freeman-Tukey transformation to stabilize variances. We will conduct meta-regression analysis to explore the effect of study-level characteristics as potential sources of heterogeneity. DISCUSSION: This proposed systematic review and meta-analysis aims to better describe HCV infection distribution across countries in the Horn of Africa sub-region of MENA; and between sub-population groups within each country. The study will provide empirical evidence necessary for researchers, policy-makers, and public health stakeholders to set research, policy, and programming priorities for HCV prevention, control, and treatment. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42014010318
Cutaneous Vasculitis and Digital Ischaemia Caused by Heterozygous Gain-of-Function Mutation in C3
It is now increasingly recognized that some monogenic autoinflammatory diseases and immunodeficiencies cause vasculitis, although genetic causes of vasculitis are extremely rare. We describe a child of non-consanguineous parents who presented with cutaneous vasculitis, digital ischaemia and hypocomplementaemia. A heterozygous p.R1042G gain-of-function mutation (GOF) in the complement component C3 gene was identified as the cause, resulting in secondary C3 consumption and complete absence of alternative complement pathway activity, decreased classical complement activity, and low levels of serum C3 with normal C4 levels. The same heterozygous mutation and immunological defects were also identified in another symptomatic sibling and his father. C3 deficiency due GOF C3 mutations is thus now added to the growing list of monogenic causes of vasculitis and should always be considered in vasculitis patients found to have persistently low levels of C3 with normal C4
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