17 research outputs found
Explainable Strategic Optimisation of Grand Scale Problems
Explainable Strategic Optimisation of grand scale problems aims to identify solutions that provide long term planning advantages to problems that cannot undergo traditional optimisation techniques due to their level of complexity. Usually, optimisation tasks focus on improving a limited number of objectives in the pursuit of obviously immediate target. However, this methodology, when applied to grand scale problems is found to be insufficient; a major reason for this is the inherent complexities typical of problems such as utility optimisation and massive logistical operations. One approach to these problems is Generational Expansion Planning that typically addresses long-term planning of country/county-wide utility problems.
This thesis draws influence from the Generational Expansion Planning field; a significant field in relation to this work as it typically focuses on large scale optimisation problems. Problems such as the improvement and maintenance of national utility operations. However, this thesis takes a novel approach that places empathises on an abstract strategic planning method that concerns itself with the extraction of design insights that can guide an experts understanding of an unrelentingly complex problem.
The proposed system was developed with data from British Telecom (BT) and was developed within their organisation in which its deployment is being planned. The techniques behind the proposed systems presented in this thesis are shown to improve the popular many-objective Non-Dominated Sorting Genetic Algorithm II in a series of experiments in which the improved Type-2 dominance method outperformed the traditional dominance method by 59%.
Several component parts are brought together within this thesis so that the unique optimisation of varied regions that exist inside the United Kingdomâs Access Network can be explored. The proposed system places great import on the interpretability of the system and the solutions that it produces. As such, an Explainable Artificial Intelligent (XAI) system has been implemented in the hope that with greater interpretability, AI systems will be able to provide solutions with greater context, nuance, and confidence, particularly when the decision of an AI model has a direct impact on a person or business. This thesis will explore the related material and will explore the proposed framework; which brings together a multitude of technologies, such as, novel fuzzy many-objective optimisation, fuzzy explainable artificial intelligence, and strategic analysis. These technologies have been approached and combined in order to develop a novel system capable of dealing with complex grand scale problems, which traditionally are tackled as piecemeal optimisation problems.
The proposed systems were shown to improve the optimisation of focused scenarios; in these experiments the proposed system was able to provide solutions for the optimisation of telecommunication networks that outperformed the current methodology for the planning/upgrading of the access network. The proposed systems were tested on rural, mixed, and urban regions of a simulated United Kingdom; it was observed that when the proposed systems were used the network solutions produced were 51.99% cheaper for rural regions, in which a combination of technologies were used as opposed to only FTTP. It was also observed that solutions produced by the proposed system in mixed regions were 54.16% cheaper while still providing the customer broadband requirements.
These results identify how an expansive system such as the novel system proposed in this thesis is able to provide sound business solutions to complex real-world problems that consists of an ever growing number of variables, constraints, and objectives. Additionally, the proposed systems are capable of producing greater understanding of design principles/choices in network solutions, which in turn provides BT and users with a greater level of trust in the solutions and the system. This is a major obstacle that must be overcome when the problem domain that is being considered is incredible vast, uncertain, and extremely vital to the success of a company.
The results of this thesis identify how the proposed systems can be developed and implemented to provide an insight into the planning and execution of an access network not required for decades to come. This is a significant change from the current reactive approach to a proactive approach that provides insight into the ever changing variables and needs of the network. The proposed systems are able to instil the confidence that allow a more thoughtful approach to be taken that is beneficial to both company and customer
Effect of a short-term low fermentable oligosaccharide disaccharide, monosaccharide and polyol (FODMAP) diet on exercise-related gastrointestinal symptoms
Background:
Research has demonstrated that low fermentable oligosaccharide disaccharide monosaccharide and polyol (FODMAP) diets improve gastrointestinal (GI) symptoms in irritable bowel syndrome sufferers. Exercise-related GI issues are a common cause of underperformance, with current evidence focusing on the use of FODMAP approaches with recreationally competitive or highly trained athletes. However, there is a paucity of research exploring the potential benefit of FODMAP strategies to support healthy, recreational athletes who experience GI issues during training. This study therefore aimed to assess whether a short-term LOWFODMAP diet improved exercise-related GI symptoms and the perceived ability to exercise in recreational runners.
Methods:
Sixteen healthy volunteers were randomly assigned in a crossover design manner to either a LOWFODMAP (16.06 ± 1.79 g·d-1) or HIGHFODMAP (38.65 ± 6.66 g·d-1) diet for 7 days, with a one week washout period followed by a further 7 days on the alternate diet. Participants rated their gastrointestinal symptoms on an adapted version of the Irritable Bowel Syndrome-Severity Scoring System (IBS-SSS) questionnaire before and at the end of each dietary period. Perceived ability to exercise (frequency, intensity and duration) in relation to each dietary period was also rated using a visual analogue scale. Resting blood samples were collected prior to and on completion of each diet to determine plasma intestinal fatty acid binding protein (I-FABP) as a marker of acute GI injury.
Results:
Overall IBS-SSS score significantly reduced in the LOWFODMAP condition from 81.1±16.4 to 31.3±9.2 (arbitrary units; P = 0.004). Perceived exercise frequency (z = 2.309, P = 0.02) and intensity (z = 2.687, P = 0.007) was significantly improved following a short-term LOWFODMAP approach compared to HIGHFODMAP. No significant differences were reported between dietary conditions for plasma I-FABP (P>0.05).
Conclusions:
A short-term LOWFODMAP diet under free-living conditions reduced exercise-related GI symptoms and improved the perceived ability to exercise in otherwise healthy, recreational runners. These findings may be explained by a reduction in indigestible carbohydrates available for fermentation in the gut. The therapeutic benefits of LOWFODMAP diets in recreational and trained athletes during sustained training periods warrants further investigation
The Impact of Decaffeinated Green Tea Extract on Fat Oxidation, Body Composition and Cardio-Metabolic Health in Overweight, Recreationally Active Individuals
This study investigated the effect of decaffeinated green tea extract (dGTE), with or without antioxidant nutrients, on fat oxidation, body composition and cardio-metabolic health measures in overweight individuals engaged in regular exercise. Twenty-seven participants (20 females, 7 males; body mass: 77.5 ± 10.5 kg; body mass index: 27.4 ± 3.0 kg·m2; peak oxygen uptake (O2peak): 30.2 ± 5.8 mL·kgâ1·minâ1) were randomly assigned, in a double-blinded manner, either: dGTE (400 mg·dâ1 (â)-epigallocatechinâ3-gallate (EGCG), n = 9); a novel dGTE+ (400 mg·dâ1 EGCG, quercetin (50 mg·dâ1) and α-lipoic acid (LA, 150 mg·dâ1), n = 9); or placebo (PL, n = 9) for 8 weeks, whilst maintaining standardised, aerobic exercise. Fat oxidation (âFATMAXâ and steady state exercise protocols), body composition, cardio-metabolic and blood measures (serum glucose, insulin, leptin, adiponectin, glycerol, free fatty acids, total cholesterol, high [HDL-c] and low-density lipoprotein cholesterol [LDL-c], triglycerides, liver enzymes and bilirubin) were assessed at baseline, week 4 and 8. Following 8 weeks of dGTE+, maximal fat oxidation (MFO) significantly improved from 154.4 ± 20.6 to 224.6 ± 23.2 mg·minâ1 (p = 0.009), along with a 22.5% increase in the exercise intensity at which fat oxidation was deemed negligible (FATMIN; 67.6 ± 3.6%O2peak, p = 0.003). Steady state exercise substrate utilisation also improved for dGTE+ only, with respiratory exchange ratio reducing from 0.94 ± 0.01 at week 4, to 0.89 ± 0.01 at week 8 (p = 0.004). This corresponded with a significant increase in the contribution of fat to energy expenditure for dGTE+ from 21.0 ± 4.1% at week 4, to 34.6 ± 4.7% at week 8 (p = 0.006). LDL-c was also lower (normalised fold change of â0.09 ± 0.06) for dGTE+ by week 8 (p = 0.038). No other significant effects were found in any group. Eight weeks of dGTE+ improved MFO and substrate utilisation during exercise, and lowered LDL-c. However, body composition and cardio-metabolic markers in healthy, overweight individuals who maintained regular physical activity were largely unaffected by dGTE
Heterotic Moduli Stabilization with Fractional Chern-Simons Invariants
We show that fractional flux from Wilson lines can stabilize the moduli of
heterotic string compactifications on Calabi-Yau threefolds. We observe that
the Wilson lines used in GUT symmetry breaking naturally induce a fractional
flux. When combined with a hidden-sector gaugino condensate, this generates a
potential for the complex structure moduli, Kahler moduli, and dilaton. This
potential has a supersymmetric AdS minimum at moderately weak coupling and
large volume. Notably, the necessary ingredients for this construction are
often present in realistic models. We explore the type IIA dual phenomenon,
which involves Wilson lines in D6-branes wrapping a three-cycle in a
Calabi-Yau, and comment on the nature of the fractional instantons which change
the Chern-Simons invariant.Comment: 43 pages. v2: references adde
The effect of two ÎČ-alanine dosing strategies on 30-minute rowing performance: a randomized, controlled trial
Background:
ÎČ-alanine (ÎČA) supplementation has been shown to increase intramuscular carnosine content and subsequent high-intensity performance in events lasting <4 minutes, which may be dependent on total, as opposed to daily, dose. The ergogenic effect of ÎČA has also been demonstrated for 2000-m rowing performance prompting interest in whether ÎČA may be beneficial for sustained aerobic exercise. This study therefore investigated the effect of two ÎČA dosing strategies on 30-minute rowing and subsequent sprint performance.
Methods:
Following University Ethics approval, twenty-seven healthy, male rowers (age: 24±2 years; body-height: 1.81±0.02m; body-mass: 82.3±2.5kg; body-fat: 14.2±1.0%) were randomised in a double-blind manner to 4 weeks of: i) ÎČA (2.4 g·d-1, ÎČA1); ii) matched total ÎČA (4.8g on alternate days, ÎČA2); or iii) cornflour placebo (2.4 g·d-1, PL). Participants completed a laboratory 30-minute rowing time-trial, followed by 3x30s maximal sprint efforts at days 0, 14 and 28 (T1-T3). Total distance (m), average power (W), relative average power (W·kg-1), cardio-respiratory measures and perceived exertion were assessed for each 10-minute split. Blood lactate ([La-]b mmol·L-1) was monitored pre-post time-trial and following maximal sprint efforts. A 3-way repeated measures ANOVA was employed for main analyses, with Bonferonni post-hoc assessment (Pâ€0.05).
Results:
Total 30-minute time-trial distance significantly increased from T1-T3 within ÎČA1 only (7397±195m to 7580±171m, P=0.002, Æp2 = 0.196), including absolute average power (194.8±18.3W to 204.2±15.5W, P=0.04, Æp2=0.115) and relative average power output (2.28±0.15W·kg-1 to 2.41±0.12W·kg-1, P=0.031, Æp2= 0.122). These findings were potentially explained by within-group significance for the same variables for the first 10 minute split (Pâ€0.01), and for distance covered (P=0.01) in the second 10-minute split. However, no condition x time interactions were observed. No significant effects were found for sprint variables (P>0.05) with comparable values at T3 for mean distance (ÎČA1: 163.9±3.8m; ÎČA2: 161.2±3.5m; PL: 162.7±3.6m), average power (ÎČA1: 352.7±14.5W; ÎČA2: 342.2±13.5W; PL: 348.2±13.9W) and lactate (ÎČA1: 10.0±0.9mmol·L-1; ÎČA2: 9.2±1.1mmol·L-1; PL: 8.7±0.9mmol·L-1).
Conclusions:
Whilst daily ÎČA may confer individual benefits, these results demonstrate limited impact of ÎČA (irrespective of dosing strategy) on 30-minute rowing or subsequent sprint performance. Further investigation of ÎČA dosage > 2.4 g·d-1 and/or chronic intervention periods (>4-8 weeks) may be warranted based on within-group observations
Finishing the euchromatic sequence of the human genome
The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers âŒ99% of the euchromatic genome and is accurate to an error rate of âŒ1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead
International Society of Sports Nutrition Position Stand: Nutritional recommendations for single-stage ultra-marathon; training and racing
Background. In this Position Statement, the International Society of Sports Nutrition (ISSN) provides an objective and critical review of the literature pertinent to nutritional considerations for training and racing in single-stage ultra-marathon. Recommendations for Training. i) Ultra-marathon runners should aim to meet the caloric demands of training by following an individualized and periodized strategy, comprising a varied, food-first approach; ii) Athletes should plan and implement their nutrition strategy with sufficient time to permit adaptations that enhance fat oxidative capacity; iii) The evidence overwhelmingly supports the inclusion of a moderate-to-high carbohydrate diet (i.e., ~60% of energy intake, 5 â 8 gâž±kgâ1·dâ1) to mitigate the negative effects of chronic, training-induced glycogen depletion; iv) Limiting carbohydrate intake before selected low-intensity sessions, and/or moderating daily carbohydrate intake, may enhance mitochondrial function and fat oxidative capacity. Nevertheless, this approach may compromise performance during high-intensity efforts; v) Protein intakes of ~1.6 g·kgâ1·dâ1 are necessary to maintain lean mass and support recovery from training, but amounts up to 2.5 gâž±kgâ1·dâ1 may be warranted during demanding training when calorie requirements are greater; Recommendations for Racing. vi) To attenuate caloric deficits, runners should aim to consume 150 - 400 kcalâž±hâ1 (carbohydrate, 30 â 50 gâž±hâ1; protein, 5 â 10 gâž±hâ1) from a variety of calorie-dense foods. Consideration must be given to food palatability, individual tolerance, and the increased preference for savory foods in longer races; vii) Fluid volumes of 450 â 750 mLâž±hâ1 (~150 â 250 mL every 20 min) are recommended during racing. To minimize the likelihood of hyponatraemia, electrolytes (mainly sodium) may be needed in concentrations greater than that provided by most commercial products (i.e., >575 mg·Lâ1 sodium). Fluid and electrolyte requirements will be elevated when running in hot and/or humid conditions; viii) Evidence supports progressive gut-training and/or low-FODMAP diets (fermentable oligosaccharide, disaccharide, monosaccharide and polyol) to alleviate symptoms of gastrointestinal distress during racing; ix) The evidence in support of ketogenic diets and/or ketone esters to improve ultra-marathon performance is lacking, with further research warranted; x) Evidence supports the strategic use of caffeine to sustain performance in the latter stages of racing, particularly when sleep deprivation may compromise athlete safety
Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study
Summary
Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally.
Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies
have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of
the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income
countries globally, and identified factors associated with mortality.
Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to
hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis,
exomphalos, anorectal malformation, and Hirschsprungâs disease. Recruitment was of consecutive patients for a
minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical
status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary
intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause,
in-hospital mortality for all conditions combined and each condition individually, stratified by country income status.
We did a complete case analysis.
Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital
diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal
malformation, and 517 with Hirschsprungâs disease) from 264 hospitals (89 in high-income countries, 166 in middleincome
countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male.
Median gestational age at birth was 38 weeks (IQR 36â39) and median bodyweight at presentation was 2·8 kg (2·3â3·3).
Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income
countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups).
Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome
countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries;
pâ€0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients
combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88â4·11],
p<0·0001; middle-income vs high-income countries, 2·11 [1·59â2·79], p<0·0001), sepsis at presentation (1·20
[1·04â1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention
(ASA 4â5 vs ASA 1â2, 1·82 [1·40â2·35], p<0·0001; ASA 3 vs ASA 1â2, 1·58, [1·30â1·92], p<0·0001]), surgical safety
checklist not used (1·39 [1·02â1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed
(ventilation 1·96, [1·41â2·71], p=0·0001; parenteral nutrition 1·35, [1·05â1·74], p=0·018). Administration of
parenteral nutrition (0·61, [0·47â0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65
[0·50â0·86], p=0·0024) or percutaneous central line (0·69 [0·48â1·00], p=0·049) were associated with lower mortality.
Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome,
middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will
be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger
than 5 years by 2030
Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19
IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19.
Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19.
DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 nonâcritically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022).
INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (nâ=â257), ARB (nâ=â248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; nâ=â10), or no RAS inhibitor (control; nâ=â264) for up to 10 days.
MAIN OUTCOMES AND MEASURES The primary outcome was organ supportâfree days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes.
RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ supportâfree days among critically ill patients was 10 (â1 to 16) in the ACE inhibitor group (nâ=â231), 8 (â1 to 17) in the ARB group (nâ=â217), and 12 (0 to 17) in the control group (nâ=â231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ supportâfree days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively).
CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes.
TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570