21 research outputs found
A Dielectric Study of Melting and Crystallization of Semi-rigid and Flexible-chain Polymers
No full textMechanical Maritime and Materials Engineerin
Rapid Situation Analysis: a hybrid, multi-methods, qualitative, participatory approach to researching tourism development phenomena
No full textThis study develops a hybrid, bottom-up approach to field research, namely Rapid
Situation Analysis, and implements it in Ghana. It draws on elements from two existing
participatory methodological approaches: Rapid Rural Appraisal and Participatory
RuralAppraisal. The approachwas developed to suit the particular needs of investigating
corporate social responsibility practices, sustainable development and poverty reduction
through tourism, a fragmented sector which tends to be ambiguous and unstructured and
lack cohesion (unlike, for example, agriculture or primary health care, both of which
are familiar territory for Rapid Rural Appraisal and Participatory Rural Appraisal). The
Rapid Situation Analysis bottom-up approach to data gathering was underpinned by
supporting methods, including participant and direct observation, in-depth interviews,
stakeholder focus groups and informal conversations. Moreover, the multiple methods
were further enriched by the collection of visual data in the form of moving and still
images. These research findings were fed back to the communities at the centre of the
research
The design of a parallel knowledge-based optical character-recognition system
No full textThree theses are combined into a treatise consisting of four parts: 1. A Literature Study, 2. The Design and Implementation, 3. Results, Conclusions and Recommendations, and 4. References and Appendices A through F. The first Part is a self-contained literature study on Parallel Processing and Pattern Recognition. It consists of four Chapters. The first Chapter introduces the NCube four/+ parallel computer on which the knowledge-based optical character-recognition system has been implemented; it also discusses computers based on other structures than a hypercube structure. The second Chapter is a survey on Parallel Processing. In this section the most common methods to parallelise a problem on existing architectures are described. The third Chapter provides some background to Pattern Recognition. An important issue will be the difference between statistical and syntactical Pattern Recognition. In Chapter four the patternrecognising process is examined more closely and is partitioned in preprocessing, classification and postprocessing. Some currently available Optical Character Recognition systems are discussed and as an extension of our literature research a model of the recogniser is presented. The second Part specifies in extenso the design, realization and implementation of the model presented in Chapter four of Part 1. Part 2 consists of four Chapters being the Chapter 5 through 8. Chapter five describes the programming environment consisting of a Scheme interpreter and a concurrent user interface that has been implemented. In the Chapters 6, 7 and 8 the design and implementations of the Preprocessor, Classifier and Postprocessor are respectively thoroughly investigated. In the third Part the results of the implemented system, some (tentative) conclusions and recommendations are presented. Part 3 contains two Chapters; 9 and 10. In Chapter nine the Results are presented, and Chapter ten provides the reader with the conclusions. Here, as a conclusion we want explicitly remark that it has turned out to be possible to combine Artificial Intelligence with traditional Pattern Recognition and that the resulting system can be speeded up by parallelisation. The fourth Part holds the appendices. Appendix A contains statistical knowledge about the fonts used in test results. In appendix B the trigram frequency tables of the ICCA Journal, the UNIX manual and this treatise can be found. Appendix C describes pre- and suffixes used in the spelling corrector. Appendix D describes the Frames used. Appendix E contains all C sources of implemented programs. Appendix F comprises the documentation concerning the Flisp interpreter.Electrical Engineering, Mathematics and Computer ScienceMathematics and Informatic
Closure of the New Waterway: An adaptive and innovative design for a navigation lock in Rotterdam
No full textThe Netherlands are protected against extreme high waters from the sea by an ingenious system of barriers. One of the most famous ones is the Maeslant barrier in the New Waterway near the port of Rotterdam. This barrier however, is subject to discussion, as it might not function as intended, because of the following reasons. It has a very low reliability regarding closing. Furthermore, because of the sea level rise, it is expected that the barrier should close much more frequently, causing more nuisance for navigation. Therefore a different solution is put forward by Spaargaren c.s. Namely to close off the New Waterway permanently by means of a barrier, consisting out of a pumping station, dewatering sluice and a lock complex. The latter one is further elaborated on by making a feasibility study for it. First of all, the best location is chosen for the barrier, which in this report is the location near Rozenburg, just east of the Maeslant barrier. Because of the high demands regarding both navigation and flood safety in combination with the uncertainty in these demands for the future, there is a need for a sophisticated design for the lock complex. This is done by first considering the boundary conditions for different (initial and adaptive) scenarios for both sets of requirements (navigation and flood safety). For navigation a larger vessel is taken into account in the adaptive boundary conditions. For flood safety, the adaptive boundary conditions results in a higher water level of about 1 meter to be retained, mostly due to a larger sea level rise. It turns out that the boundary conditions regarding navigation have a way larger impact in the design choices of the lock complex than the boundary conditions regarding flood safety. The above boundary conditions are used to create an overall solution for the barrier. 4 locks are needed (in case of an initial design): one large lock for large seagoing vessels, one mid-sized lock for smaller seagoing vessels and two for inland going vessels. When looking at the adaptive requirements, another mid-sized lock should be added. For the large lock, different principal solutions are developed that also take the adaptive boundary conditions into account. First of all, an adaptive design of a lock head is considered by making the head modular. This makes it possible to place a larger gate in the head later on. It turns out that this is probably not cost-efficient. The second proposed solution is to use a retaining wall in combination with a relieving floor for the chamber walls of the large lock for seagoing vessels. The relieving floor will decrease the horizontal soil loads on the soil retaining wall beneath it, which is structurally beneficial. This relieving floor will be combined with a longitudinal filling system. A longitudinal culvert over the length of the lock is placed on top of the relieving floor. Filling and emptying will be done using openings in the floor of the superstructure. The load on vessels during levelling of the lock are determined for this system, which is the main requirement that determines the filling time. It turns out that this option results in much faster levelling times compared to other levelling systems. Levelling could be done a factor 3 faster than filling through the head. It is concluded that the longitudinal culvert in combination with the relieving floor can compete with conventional filling systems. Furthermore, it fits in an adaptive design approach, because even with a wider lock, faster levelling times are possible. However, there are still some considerations to be made regarding this solution. A thorough cost-benefit analysis should be made. Besides of this, the hydraulic computations should be validated by means of a scale model or computational fluid dynamics.Civil Engineering and GeosciencesHydraulic EngineeringHydraulic structures and flood ris
Iron deficiency and acute seizures: results from children living in rural Kenya and a meta-analysis.
No full textThere are conflicting reports on whether iron deficiency changes susceptibility to seizures. We examined the hypothesis that iron deficiency is associated with an increased risk of acute seizures in children in a malaria endemic area
Haptoglobin, Alpha-thalassaemia and Glucose-6-phosphate\ud Dehydrogenase Polymorphisms and Risk of Abnormal\ud Transcranial Doppler among Patients with Sickle cell\ud anaemia in Tanzania
No full textTranscranial Doppler ultrasonography measures cerebral blood flow velocity (CBFv) of basal intracranial vessels and is used clinically to detect stroke risk in children with sickle cell anaemia (SCA). Co-inheritance in SCA of alpha-thalassaemia and glucose-6-phosphate dehydrogenase (G6PD) polymorphisms is reported to associate with high CBFv and/or risk of stroke. The effect of a common functional polymorphism of haptoglobin (HP) is unknown. We investigated the effect of co-inheritance of these polymorphisms on CBFv in 601 stroke-free Tanzanian SCA patients aged <24 years. Homozygosity for alpha-thalassaemia 3_7 deletion was significantly associated with reduced mean CBFv compared to wild-type (b-coefficient_16_1 cm/s, P = 0_002) adjusted for age and survey year. Inheritance of 1 or 2 alpha-thalassaemia deletions was associated with decreased risk of abnormally high CBFv, compared to published data from Kenyan healthy control children (Relative risk ratio [RRR] = 0_53 [95% confidence interval (CI):0_35–0_8] & RRR = 0_43 [95% CI:0_23–0_78]), and reduced risk of abnormally low CBFv for 1 deletion only (RRR = 0_38 [95% CI:0_17–0_83]). No effects were observed for G6PD or HP polymorphisms. This is the first report of the effects of co-inheritance of common polymorphisms, including the HP polymorphism, on CBFv in SCA patients resident in Africa and confirms the importance of alpha-thalassaemia in reducing risk of abnormal CBFv
Children with severe malnutrition: can those at highest risk of death be identified with the WHO protocol?
No full textBackground: With strict adherence to international recommended treatment guidelines, the case fatality for severe malnutrition ought to be less than 5%. In African hospitals, fatality rates of 20% are common and are often attributed to poor training and faulty case management. Improving outcome will depend upon the identification of those at greatest risk and targeting limited health resources. We retrospectively examined the major risk factors associated with early (<48 h) and late in-hospital death in children with severe malnutrition with the aim of identifying admission features that could distinguish a high-risk group in relation to the World Health Organization (WHO) guidelines.
Methods and findings: Of 920 children in the study, 176 (19%) died, with 59 (33%) deaths occurring within 48 h of admission. Bacteraemia complicated 27% of all deaths: 52% died before 48 h despite 85% in vitro antibiotic susceptibility of cultured organisms. The sensitivity, specificity, and likelihood ratio of the WHO-recommended “danger signs” (lethargy, hypothermia, or hypoglycaemia) to predict early mortality was 52%, 84%, and 3.4% (95% confidence interval [CI] = 2.2 to 5.1), respectively. In addition, four bedside features were associated with early case fatality: bradycardia, capillary refill time greater than 2 s, weak pulse volume, and impaired consciousness level; the presence of two or more features was associated with an odds ratio of 9.6 (95% CI = 4.8 to 19) for early fatality (p < 0.0001). Conversely, the group of children without any of these seven features, or signs of dehydration, severe acidosis, or electrolyte derangements, had a low fatality (7%).
Conclusions: Formal assessment of these features as emergency signs to improve triage and to rationalize manpower resources toward the high-risk groups is required. In addition, basic clinical research is necessary to identify and test appropriate supportive treatments
Estimating the Clinical and Economic Impact of Introducing a New Antibacterial into Greek Clinical Practice for the Management of Hospital-Acquired Infections with Limited Treatment Options
No full textIntroduction: Hospital-acquired infections (HAIs) and growing antimicrobial resistance (AMR) represent a significant healthcare burden globally. Especially in Greece, HAIs with limited treatment options (LTO) pose a serious threat due to increased morbidity and mortality. This study aimed to estimate the clinical and economic value of introducing a new antibacterial for HAIs with LTO in Greece. Methods: A previously published and validated dynamic model of AMR was adapted to the Greek setting. The model estimated the clinical and economic outcomes of introducing a new antibacterial for the treatment of HAIs with LTO in Greece. The current treatment pathway was compared with introducing a new antibacterial to the treatment sequence. Outcomes were assessed from a third-party payer perspective, over a 10-year transmission period, with quality-adjusted life years (QALYs) and life years (LYs) gained considered over a lifetime horizon. Results: Over the next 10 years, HAIs with LTO in Greece account for approximately 1.4 million hospital bed days, hospitalisation costs of more than €320 million and a loss of approximately 403,000 LYs (319,000 QALYs). Introduction of the new antibacterial as first-line treatment provided the largest clinical and economic benefit, with savings of up to 93,000 bed days, approximately €21 million in hospitalisation costs and an additional 286,000 LYs (226,000 QALYs) in comparison to the current treatment strategy. The introduction of a new antibacterial was linked to a monetary benefit of €6.8 billion at a willingness to pay threshold of €30,000 over 10 years. Conclusion: This study highlights the considerable clinical and economic benefit of introducing a new antibacterial for HAIs with LTO in Greece. This analysis shows the additional benefit when a new antibacterial is introduced to treatment sequences. These findings can be used to inform decision makers to implement policies to ensure timely access to new antibacterial treatments in Greece. © 2022, The Author(s)
Functionalised oximes : emergent precursors for carbon-, nitrogen- and oxygen-centred radicals
No full textThe author thanks EaStCHEM for financial support.Oxime derivatives are easily made, are non-hazardous and have long shelf lives. They contain weak N–O bonds that undergo homolytic scission, on appropriate thermal or photochemical stimulus, to initially release a pair of N- and O-centred radicals. This article reviews the use of these precursors for studying the structures, reactions and kinetics of the released radicals. Two classes have been exploited for radical generation; one comprises carbonyl oximes, principally oxime esters and amides, and the second comprises oxime ethers. Both classes release an iminyl radical together with an equal amount of a second oxygen-centred radical. The O-centred radicals derived from carbonyl oximes decarboxylate giving access to a variety of carbon-centred and nitrogen-centred species. Methods developed for homolytically dissociating the oxime derivatives include UV irradiation, conventional thermal and microwave heating. Photoredox catalytic methods succeed well with specially functionalised oximes and this aspect is also reviewed. Attention is also drawn to the key contributions made by EPR spectroscopy, aided by DFT computations, in elucidating the structures and dynamics of the transient intermediates.Peer reviewe
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Comparative analysis of hypertensive nephrosclerosis in animal models of hypertension and its relevance to human pathology. Glomerulopathy
No full textCurrent research on hypertension utilizes more than fifty animal models that rely mainly on stable increases in systolic blood pressure. In experimental hypertension, grading or scoring of glomerulopathy in the majority of studies is based on a wide range of opinion-based histological changes that do not necessarily comply with lesional descriptors for glomerular injury that are well-established in clinical pathology. Here, we provide a critical appraisal of experimental hypertensive glomerulopathy with the same approach used to assess hypertensive glomerulopathy in humans. Four hypertensive models with varying pathogenesis were analyzed–chronic angiotensin II infused mice, mice expressing active human renin in the liver (TTRhRen), spontaneously hypertensive rats (SHR), and Goldblatt two-kidney one-clip rats (2K1C). Analysis of glomerulopathy utilized the same criteria applied in humans–hyalinosis, focal segmental glomerulosclerosis (FSGS), ischemic, hypertrophic and solidified glomeruli, or global glomerulosclerosis (GGS). Data from animal models were compared to human reference values. Kidneys in TTRhRen mice, SHR and the nonclipped kidneys in 2K1C rats had no sign of hyalinosis, FSGS or GGS. Glomerulopathy in these groups was limited to variations in mesangial and capillary compartment volumes, with mild increases in collagen deposition. Histopathology in angiotensin II infused mice corresponded to mesangioproliferative glomerulonephritis, but not hypertensive glomerulosclerosis. The number of nephrons was significantly reduced in TTRhRen mice and SHR, but did not correlate with severity of glomerulopathy. The most substantial human-like glomerulosclerotic lesions, including FSGS, ischemic obsolescent glomeruli and GGS, were found in the clipped kidneys of 2K1C rats. The comparison of affected kidneys to healthy control in animals produces lesion values that are numerically impressive but correspond to mild damage if compared to humans. Animal studies should be standardized by employing the criteria and classifications established in human pathology to make experimental and human data fully comparable for comprehensive analysis and model improvements. © 2022 Gutsol et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
