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Natural convection from a triangular array of isothermal horizontal cylinders
No full textNatural convection heat transfer from three isothermally heated horizontal cylinders submerged in water in a triangular arrangement is investigated. Two configurations, named here as one over two and two over one, are characterised for three cylinder spacings ( = 2, 3 and 4 cylinder diameters) and Rayleigh number conditions ( = 2, 4 × 106 and 6 × 106). Combined local heat flux measurements and flow velocity measurements using particle image velocimetry are employed to examine the governing heat transfer mechanisms. For many cases of the one over two configuration, substantial differences from the single cylinder case are noted. The buoyant plumes generated from the two lower cylinders interact with the flow field and heat transfer around the upper cylinder, altering the local fluid velocities and temperature fields. This effect is dependent on both the inter-cylinder spacing and the Rayleigh number condition. For the two over one setup, both upper cylinders for all cases, except and = 6 × 106, behave in the same manner as a single cylinder. This is due to the competing effects of the buoyant plume rising from the lower cylinder and the restriction of flow through the gap between the two upper cylinders
Hypertensive disorders of pregnancy and behavioural outcomes in the offspring: Findings from the Millennium Cohort Study
No full textBackground: The aim of this study was to examine the association between hypertensive disorders of pregnancy (HDP) and behavioural outcomes in offspring at five time-points. Methods: We used maternal-reported data from the Millennium Cohort Study. Data on HDP were collected when children were 9-months. Data on behavioural outcomes were collected at age 3, 5, 7, 11 and 14years using the Strengths and Difficulties Questionnaire (SDQ). Multivariate logistic regression analysis examined a HDP-behavioural difficulties relationship, using validated SDQ cut-off points. Multilevel models with linear splines examined the association between HDP and repeated measures of SDQ. Results: 18,274 singleton children were included in the study at baseline, Multivariate logistic regression suggested HDP was not significantly associated with SDQ domain cut-off points at ages 3, 7 and 11years. At age 5years, HDP was associated with a 40% increased odds of behavioural difficulties based on total SDQ(≥17) (OR:1.40, 95% CI:1.03,1.91). HDP was associated with a 43% increased odds of Peer Problem difficulties at age 5 (OR:1.43, 95% CI:1.10,1.86), and a 28% increased odds of Peer Problem difficulties(≥4) at age 14 (OR:1.28, 95% CI:1.02,1.61). In the linear spline model, mean SDQ score was higher at each time-point in those exposed to HDP, although did not always reach statistical significance. Limitations: Data on different classifications of HDP were unavailable; therefore, we could not examine the effect of gestational hypertension and preeclampsia separately. Conclusions: While we did not find strong evidence of associations between HDP and behavioural outcomes overall, some associations between HDP and behavioural difficulties did persist at age 5 and 14years
Audio Impairment Recognition using a Correlation-Based Feature Representation
No full textThe 2020 Twelfth International Conference on Quality of Multimedia Experience (QoMEX), Athlone, Ireland (held online due to coronavirus outbreak), 26-28 May 2020Audio impairment recognition is based on finding noise in audio files and categorising the impairment type. Recently, significant performance improvement has been obtained thanks to the usage of advanced deep learning models. However, feature robustness is still an unresolved issue and it is one of the main reasons why we need powerful deep learning architectures. In the presence of a variety of musical styles, handcrafted features are less efficient in capturing audio degradation characteristics and they are prone to failure when recognising audio impairments and could mistakenly learn musical concepts rather than impairment types. In this paper, we propose a new representation of hand-crafted features that is based on the correlation of feature pairs. We experimentally compare the proposed correlation-based feature representation with a typical raw feature representation used in machine learning and we show superior performance in terms of compact feature dimensionality and improved computational speed in the test stage whilst achieving comparable accuracy.Science Foundation IrelandInsight Research CentreThe Engineering and Physical Sciences Research CouncilThe Alan Turing Institut
Speech Quality Factors for Traditional and Neural-Based Low Bit Rate Vocoders
No full textInternational Conference on Quality of Multimedia Experience (QoMEX), Dublin, Ireland, 26-28 May 2020This study compares the performances of different algorithms for coding speech at low bit rates. In addition to widely deployed traditional vocoders, a selection of recently developed generative-model-based coders at different bit rates are contrasted. Performance analysis of the coded speech is evaluated for different quality aspects: accuracy of pitch periods estimation, the word error rates for automatic speech recognition, and the influence of speaker gender and coding delays. A number of performance metrics of speech samples taken from a publicly available database were compared with subjective scores. Results from subjective quality assessment do not correlate well with existing full reference speech quality metrics. The results provide valuable insights into aspects of the speech signal that will be used to develop a novel metric to accurately predict speech quality from generative-model-based coders.Science Foundation IrelandInsight Research Centr
How Crisp is the Crease? A Subjective Study on Web Browsing Perception of Above-The-Fold
No full textThe IEEE Conference on Network Softwarization (NetSoft 2020), Virtual Conference, 30 June - 3 July 2020Quality of Experience (QoE) for various types of websites has gained significant attention in recent years. In order to design and evaluate websites, a metric that can estimate a user’s experienced quality robustly for diverse content is necessary. SpeedIndex (SI) has been widely adopted to estimate perceived web page loading progress. It measures the speed of rendering pixels for the webpage that is visible in the browser window. This is termed Above-The-Fold (ATF). The influence of animated content on the perception of ATF has been less comprehensively explored. In this paper, we present an experimental design and methodology to measure ATF perceptionfor websites with and without animated elements for various pagecontent categories. We found that pages with animated elements caused people to have more varied perceptions of ATF under different network conditions. Animated content also impacts the page load estimation accuracy of SI for websites. We discuss how the difference in the perception of ATF will impact the QoE management of web applications. We explain the necessity of revisiting the visual assessment of ATF to include the animated contents and improve the robustness of metrics like SI.European Commission - European Regional Development FundScience Foundation IrelandInsight Research Centr
Assessment of the biological activity of fish muscle protein hydrolysates using in vitro model systems
No full textThe generation of biologically active fish protein hydrolysates (FPH) is a useful technique to produce value-added products with potential application in the functional food and nutraceutical industries. Fish muscle is an attractive substrate for the production of protein hydrolysates due to its rich protein content, containing 15-25% of total fish protein. This paper reviews the production of protein hydrolysates from fish muscle, most commonly via enzymatic hydrolysis, and their subsequent bioactivities including anti-obesity, immunomodulatory, antioxidant, angiotensin I-converting enzyme (ACE)-inhibitory, anti-microbial, and anti-cancer activities as measured by in vitro testing methods. Disease prevention with FPH potentially offers a safe and natural alternative to synthetic drugs. Small molecular weight (MW) FPHs generally exhibit favourable bioactivity than large MW fractions via enhanced absorption through the gastrointestinal tract. This review also discusses the relationship between amino acid (AA) composition and AA sequence of FPH and peptides and their exhibited in vitro bioactivity
How do delirium motor subtypes differ in phenomenology and contributory aetiology? a cross-sectional, multisite study of liaison psychiatry and palliative care patients
No full textObjectives To investigate whether delirium motor subtypes differ in terms of phenomenology and contributory aetiology. Design Cross-sectional study. Setting International study incorporating data from Ireland and India across palliative care, old age liaison psychiatry and general adult liaison psychiatry settings. Participants 1757 patients diagnosed with delirium using criteria from the Diagnostic and Statistical Manual of Mental Disorders, Fourth edition (DSM IV). Primary and secondary outcome measures Hyperactive, mixed and hypoactive delirium subtypes were identified using the abbreviated version of the Delirium Motor Subtype Scale. Phenomenology was assessed using the Delirium Rating Scale Revised. Contributory aetiologies were assessed using the Delirium Aetiology Checklist (DEC), with a score >2 indicating that the aetiology was likely or definitely contributory. Results Hypoactive delirium was associated with dementia, cerebrovascular and systemic infection aetiologies (p<0.001) and had a lower overall burden of delirium symptoms than the other motor subtypes. Hyperactive delirium was associated with younger age, drug withdrawal and the DEC category other systemic
aetiologies (p<0.001). Mixed delirium showed the greatest symptom burden and was more often associated with drug intoxication and metabolic disturbance (p<0.001). All three delirium motor subtypes had similar levels of impairment in attention and visuospatial functioning but differed significantly when compared with no subtype (p<0.001). Conclusions This study indicates a pattern of aetiology and symptomatology of delirium motor subtypes across a large international sample that had previously been
lacking. It serves to improve our understanding of this complex condition and has implications in terms of early detection and management of delirium
Scratching the surface: a review of online misinformation and conspiracy theories in atopic dermatitis
No full textMisinformation is one of the greatest threats to global health. Atopic dermatitis (AD) is a common skin disorder with a complex multifactorial aetiology, rendering it susceptible to misinformation. Little is known about the content of misinformation regarding AD online. We performed a review of misinformation related to AD available online, via PubMed for scientific papers and via Google for non-scientific websites. Key areas of misinformation were identified, including \u27simple cures\u27 for AD, diet, chemicals, dust, vaccines, red skin syndrome, and alternative therapies. Patients with AD and their families are vulnerable to misinformation given the severe impact of AD on quality of life. Dermatologists must be aware of the false content being shared online related to AD, and be prepared to refute and rebut misinformation by providing appropriate evidence
Taxonomy and ecology of epilithic diatoms in Irish lakes
No full textBenthic algae are significant primary producers and important in biogeochemical cycling in shallow lakes in particular, but epilithic diatom ecology is poorly understood compared to phytoplankton and higher trophic levels. I explored diatom taxonomy and ecology to investigate the suitability of epilithic diatoms for determining the biological condition of Irish lakes. I examined intraspecific variation in populations of two widespread diatom genera to understand the implication of diatom species-complexes for biodiversity and environmental assessments.
Diatom composition in 220 samples from the epilithon of 91 limnologically diverse reference and impacted lakes was analysed, with a replicated spring and summer analysis in my study. Multivariate techniques enabled six characteristic groups of diatom assemblages and their relationship with key abiotic environmental variables to be identified. It revealed that physicochemical gradients of alkalinity-pH, total phosphorus and true colour explained the greatest amount of variation in diatom assemblages in both seasons.
Lake classifications are successful when diatom metrics reliably reflect the response of assemblages to environmental stressor gradients. The Lake Trophic Diatom Index was validated for Water Framework Directive classifications after reference condition was assessed and a highly significant relationship with total phosphorus was identified. This represents an improvement on a previous study that found diatom indices to be poor indicators of trophic condition in Irish lakes. A key finding relative to comparable international studies was that the diatom-phosphorus relationship was not confounded by factors such as lake type. The clearest seasonal pattern that emerged was a consistently low variability in index scores in high status lakes, with variability increasing with declining trophic condition thereafter. Nevertheless, averaging seasonal metric scores provided broadly equivalent levels of explained variation relative to that reported for other phototrophic indices.
The distribution, morphology and ultrastructure of Brachysira and Encyonopsis in a large number of river and lake populations was assessed. Examination of original type material for morphologically challenging Encyonopsis provided new information and taxonomic uncertainty in E. angusta was resolved by a proposed synonymy with E. krammeri. Four new diatom species were described, and greater morphological diversity was discovered. Further validation of nomenclatural types and molecular characterisation is required before many cosmopolitan morphospecies can be formally named. My analyses provided support for the concept of taxonomic redundancy within diatom complexes given the adequate performance of the diatom metric and comparability of species trophic optima when assessed with weighted averaging. However, I also found evidence for differences in ecological niches amongst new and established species that suggested potential for improvements in precision in environmental indices are also achievable.
My study provided a rare example of a contemporary taxonomic investigation for a group of freshwater algae in Irish waters. The broader implication of my findings is that algal diversity in Ireland is actually quite poorly documented. As such, my research provides further opportunities to understand patterns of diatom diversity in the near future. The final chapter of this thesis summarises and discusses the role of diatoms and benthic algal indicators for lake phytobenthos classifications, with suggestions for future research areas
Metformin therapy and severity and mortality of SARS-CoV-2 infection: a meta-analysis
No full textBackground: It has been postulated that metformin could have anti-SARS-CoV-2 action. This raises the hypothesis that people who take metformin may have lower SARS-CoV-2 severity and/or mortality. Objective To conduct a meta-analysis of the association between the use of Metformin and risk of severity and mortality in SARS-CoV-2 infection. Data Sources We searched PubMed, EMBASE, Google scholar, the Cochrane Database of Systematic Reviews and preprint servers (medRxiv and Research Square) for studies published between December 2019 and January 2021. Data was extracted on study location, year of publication, design, number of participants, sex, age at baseline, body mass index, and exposure and outcome definition. Effect statistics were pooled using random effects models with 95% confidence intervals (CI). The quality of included studies was assessed with the Newcastle–Ottawa Scale (NOS). Results Thirty-two observational studies were included, combining to a total sample of 44306 participants. The mean NOS score of included studies was 7.9. Results suggested that metformin use was associated with a reduced risk of SARS-CoV-2 mortality (OR= 0.56, 95% CI: 0.46-0.68, p<0.001; 22 studies) but not to disease severity (OR=0.85, 95% CI: 0.71-1.02, p=0.077; 15 studies). In the subgroup analysis, metformin reduces the risk of mortality (OR = 0.69, 95% CI: 0.55-0.88; p=0.002) and severity (OR = 0.83, 95% CI: 0.70-0.97, p=0.023) in patients aged 70 and above. Conclusions The use of metformin was associated to lower risk of mortality from SARS-CoV-2 infection. This association does not imply causation and further research is required to clarify potential mechanisms