Morphological Variations of the “Baby\'s Supply Line”

To contribute to the sparse information on dimensional variations of umbilical cords in Ghana, 124 placentae with attached umbilical cords were studied. The placentae were obtained from the University of Science and Technology Hospital between 2000 and 2002. Average cord length was 47.04cm (SD 12.8cm) with the shortest cord being 5.5cm and the longest 75.50cm. By empirical definition, 21.56% of the cords were Short whereas, 78.44% were long. Most of the umbilical cords (63%) had empirically eccentric attachments to their placentae; 20.48% had central and 16.52% had marginal attachments respectively. Occurrence of furcate insertion of umbilical cord vessels into the placenta was 28% and non-furcate insertion was 72%. These quantitative data provide baseline values for further investigation. Keywords: umbilical cords, morphology, length, attachments, looping, insertion Journal of Science and Technology Vol. 28 (2) 2008: pp. 1-

Rock Characteristics and Ball Mill Energy Requirements at Goldfields Ghana Limited, Tarkwa Gold Mine (TGM)

Mineral processing plants often experience changes in throughput; blending patterns, and rock properties. These changes can have great impact on milling operations. As mining progresses, new deposits are discovered, which may have different characteristics from the designed plant parameters, a situation requiring re-assessment of the plant operating parameters. Goldfields Ghana Limited, Tarkwa Gold Mine (TGM), processes ores which occur in conglomerate reefs. The competence of the ore was observed to increase with increasing mining depth. Other rock properties such as porosity, micro-cracks and gold dissolution were also observed to change with depth. It therefore became necessary to conduct a study to ascertain the effect of changes in rock characteristics on the performance of the existing ball mill. The study characterized the mineralogy and rock characteristics of the ores being mined from three pits and the results were compared with design parameters. The parameters examined had deviated from the design; Work Index (WI) for example was lower than design and required simulation and adjustment. Samples taken at the same depth from each of the pits showed that Akontasi Pit has the most competent ores, followed by Kottraverchi Pit and then Teberebie Pit. Furthermore, throughput was the most sensitive variable and easiest to manipulate to achieve the energy draw required. Simulations showed that a plant throughput of about 1665 t/hr, instead of the current value of 1500 t/hr would be most suitable as an energy draw solution.Keywords: Work index, Power draw, Computer simulatio

Component reliability test approaches for marine renewable energy

Philipp R Thies University of Exeter Cornwall Campus College of Engineering, Mathematics and Physical Science Penryn Cornwall TR10 9FE United KingdomArticleThis version is the author’s manuscript of the published article. Please cite the published version as: Thies PR, Johanning L, Karikari-Boateng KA, Ng C, McKeever P. (2015). Component reliability test approaches for marine renewable energy. Proc IMechE Part O: Journal of Risk and Reliability, Spec. Issue, Vol. 229 (5), pp. 403-416, DOI:10.1177/1748006X15580837.An increasing number of marine renewable energy (MRE) systems are reaching the stage where a working prototype must be demonstrated in operation in order to progress to the next stage of commercial projects. This stage is often referred to as ‘valley of death’ where device developers face the challenge of raising capital needed to demonstrate the prototype. The dilemma is that investors understandably demand a proven track record and demonstrated reliability in order to provide capital. One way to resolve this dilemma is specific component reliability testing that not only satisfies investor expectations but holds the potential to improve and de-risk components for MRE. This paper gives an overview to different component reliability test approaches in established industries and for MRE, covering both wave and tidal energy technologies. There has been notable activity in the research community to develop and implement dedicated component reliability test rigs that allow the investigation and demonstration of component reliability under controlled, yet representative conditions. Two case studies of physical test rigs will illustrate the possible test approaches. The Nautilus Powertrain test rig, a facility at the Offshore Renewable Energy (ORE) Catapult, focuses on the demonstration and testing of drive train components including gearboxes, generators, mechanical couplings and bearings. The Dynamic Marine Component test rig (DMaC) at the University of Exeter aims to replicate the forces and motions for floating offshore applications and their subsystems, including mooring lines and power cables. This paper highlights the relevance of component testing and qualification prior to large-scale commercial deployments and gives an insight to some of the test capabilities available in the sector. Several case studies illustrate the component test approach for tidal energy (Nautilus) and wave energy (DMaC) applications.European Union’s European Regional Development Fund (ERDF)Department of Energy and Climate Change (DECC)Peninsula Research Institute for Marine Renewable Energy (PRIMaRE)Engineering and Physical Sciences Research Council (EPSRC)Energy Technoliogy Istitute (ETI)Research Councils UK (RCUK) Energy programmeIndustrial Doctorate Centre in Offshore Renewable Energy (IDCORE

Fasting blood glucose and glycosylated haemoglobin levels in randomly selected Ghanaian diabetic patients – the clinical implications

This work involved the measurement of fasting blood glucose (FBG) and glycosylated haemoglobin (HbA1c) levels of diabetes mellitus patients as an index of glycaemic control. It was a prospective casefinding study using laboratory and general practice records. The subjects were confirmed diabetic patients, attending a Diabetic Clinic at the Komfo Anokye Teaching Hospital, Kumasi, Ghana. The fasting blood glucose levels were measured in millimolar concentration and corrected glycosylated haemoglobin (HbA1c) levels expressed as percentages. The mean level of fasting blood glucose (± standard deviation) for the non-diabetics was 4.91 ± 1.08 mmol/L and the corresponding mean value for the HbA1c was 5.40 ± 0.84%. There was a linear correlation between the fasting blood glucose and HbA1c. Out of the 99 diabetics, 9 of them had near-normal levels of HbA1c while 64 had mean values between 12 and 16%. There was generally high levels of glycosylated haemoglobin in the majority of patients studied, reflecting their poor glycaemic control. This suggests a relatively large proportion of the diabetics could be predisposed to microvascular complications, while a small group with near-normal HbA1c levels could be prone to hypoglycaemic complications. Journal of Science and Technology Vol. 26(1) 2006: 8-1

Long-Term Dynamic Behaviour of Human Resource Needs in Ghana’s Oil Sector: System Dynamics Approach

This study espouses a multi-strategy method comprising of a qualitative study and system dynamics (SD) to deliver the long-term dynamic behaviour of human resource development (HRD) in Ghana’s oil and gas sector. The adoption of the SD differed from previous studies addressing the local content implementation challenge of human resources, thereby allowing HRD to be considered a ‘system’ which, in turn, aided in comprehensively identifying and analysing the interrelationships among the dominant variables. Focal articles were reviewed to develop a causal loop diagram (CLD) for human resource and subsequently validated qualitatively. The CLD was used for analysing interconnections among the variables in the HRD and as a basis for developing the stock and flow diagram for projections. The study found that local content investment is projected to increase from $799 million to$3.0807 billion in 50 years, with a corresponding revenue increase from $29 billion to$44 billion in 50 years. Subsequent sensitivity analysis compared the local content model results under varying situations, which indicated the possibility of a demand for 20,000 local staff. The study further uncovered two critical issues affecting HRD, namely policy coordination and harmonisation and sustainable funding. These issues are exacerbated by the pervasive political interference in the administrative and operational functions of state oil and gas institutions

Ultrafast Dynamics of Nitro−Nitrite Rearrangement and Dissociation in Nitromethane Cation

We report new insights into the ultrafast rearrange- ment and dissociation dynamics of nitromethane cation (NM+) using pump−probe measurements, electronic structure calculations, and ab initio molecular dynamics simulations. The “roaming” nitro−nitrite rearrangement (NNR) pathway involving large- amplitude atomic motion, which has been previously described for neutral nitromethane, is demonstrated for NM+. Excess energy resulting from initial population of the electronically excited D2 state of NM+ upon strong-field ionization provides the necessary energy to initiate NNR and subsequent dissociation into NO+. Both pump−probe measurements and molecular dynamics simulations are consistent with the completion of NNR within 500 fs of ionization with dissociation into NO+ and OCH3 occurring ∼30 fs later. Pump−probe measurements indicate that NO+ formation is in competition with the direct dissociation of NM+ to CH3+ and NO2. Electronic structure calculations indicate that a strong D0 → D1 transition can be excited at 650 nm when the C−N bond is stretched from its equilibrium value (1.48 Å) to 1.88 Å. On the other hand, relaxation of the NM+ cation after ionization into D0 occurs in less than 50 fs and results in observation of intact NM+. Direct dissociation of the equilibrium NM+ to produce NO2+ and CH3 can be induced with 650 nm excitation via a weakly allowed D0 → D2 transition

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

SPO11-Independent DNA Repair Foci and Their Role in Meiotic Silencing

In mammalian meiotic prophase, the initial steps in repair of SPO11-induced DNA double-strand breaks (DSBs) are required to obtain stable homologous chromosome pairing and synapsis. The X and Y chromosomes pair and synapse only in the short pseudo-autosomal regions. The rest of the chromatin of the sex chromosomes remain unsynapsed, contains persistent meiotic DSBs, and the whole so-called XY body undergoes meiotic sex chromosome inactivation (MSCI). A more general mechanism, named meiotic silencing of unsynapsed chromatin (MSUC), is activated when autosomes fail to synapse. In the absence of SPO11, many chromosomal regions remain unsynapsed, but MSUC takes place only on part of the unsynapsed chromatin. We asked if spontaneous DSBs occur in meiocytes that lack a functional SPO11 protein, and if these might be involved in targeting the MSUC response to part of the unsynapsed chromatin. We generated mice carrying a point mutation that disrupts the predicted catalytic site of SPO11 (Spo11YF/YF), and blocks its DSB-inducing activity. Interestingly, we observed foci of proteins involved in the processing of DNA damage, such as RAD51, DMC1, and RPA, both in Spo11YF/YFand Spo11 knockout meiocytes. These foci preferentially localized to the areas that undergo MSUC and form the so-called pseudo XY body. In SPO11-deficient oocytes, the number

Differing Requirements for RAD51 and DMC1 in Meiotic Pairing of Centromeres and Chromosome Arms in Arabidopsis thaliana

During meiosis homologous chromosomes pair, recombine, and synapse, thus ensuring accurate chromosome segregation and the halving of ploidy necessary for gametogenesis. The processes permitting a chromosome to pair only with its homologue are not fully understood, but successful pairing of homologous chromosomes is tightly linked to recombination. In Arabidopsis thaliana, meiotic prophase of rad51, xrcc3, and rad51C mutants appears normal up to the zygotene/pachytene stage, after which the genome fragments, leading to sterility. To better understand the relationship between recombination and chromosome pairing, we have analysed meiotic chromosome pairing in these and in dmc1 mutant lines. Our data show a differing requirement for these proteins in pairing of centromeric regions and chromosome arms. No homologous pairing of mid-arm or distal regions was observed in rad51, xrcc3, and rad51C mutants. However, homologous centromeres do pair in these mutants and we show that this does depend upon recombination, principally on DMC1. This centromere pairing extends well beyond the heterochromatic centromere region and, surprisingly, does not require XRCC3 and RAD51C. In addition to clarifying and bringing the roles of centromeres in meiotic synapsis to the fore, this analysis thus separates the roles in meiotic synapsis of DMC1 and RAD51 and the meiotic RAD51 paralogs, XRCC3 and RAD51C, with respect to different chromosome domains