Miracle-dz/UniFAR-FTUs huggingface dataset:
Hydrodynamic analysis of a vertical axis tidal current turbine

Tidal currents can be used as a predictable source of sustainable energy, and have the potential to make a useful contribution to the energy needs of the UK and other countries with such a resource. One of the technologies which may be used to transform tidal power into mechanical power is a vertical axis turbine, the hydrodynamic analysis of which this thesis is concerned with. The aim of this analysis is to gain a better understanding of the power transformation process, from which position there is the possibility of improving the conversion efficiency. A second aim is to compare the results from different modelling approaches. Two types of mathematical modelling are used: a basic blade element momentum model and a more complex Reynolds-averaged Navier Stokes (RANS) model. The former model has been programmed in Matlab by the present author while the latter model uses a commercial computational fluid dynamics (CFD) code, ANSYS CFX. This RANS model uses the SST k-ω turbulence model. The CFD analysis of hydrofoils (equally airfoils), for both fixed and oscillating pitch conditions, is a significant proportion of the present work. Such analysis is used as part of the verification and validation of the CFD model of the turbine. It is also used as input to the blade element momentum model, thereby permitting a novel comparison between the blade element momentum model and the CFD model of the turbine. Both types of turbine model were used to explore the variation in turbine efficiency (and other factors) with tip speed ratio and with and without an angle of attack limiting variable pitch strategy. It is shown that the use of such a variable pitch strategy both increases the peak efficiency and broadens the peak. The comparison of the results from the two different turbine modelling approaches shows that when the present CFD hydrofoil results are used as input to the blade element model, and when dynamic effects are small and the turbine induction factor is low, there is generally good agreement between the two models. Declaration of originality I hereby declare that this thesis has been composed by myself and that except where stated, the work contained is my own. I also declare that the work contained in this thesis has not been submitted for any other degree or professional qualification except as specified.
On Randomized and Quantum Query Complexities

We study randomized and quantum query (a.k.a. decision tree) complexity for all total Boolean functions, with emphasis to derandomization and dequantization (removing quantumness from algorithms). Firstly, we show that $D(f) = O(Q_1(f)^3)$ for any total function $f$, where $D(f)$ is the minimal number of queries made by a deterministic query algorithm and $Q_1(f)$ is the number of queries made by any quantum query algorithm (decision tree analog in quantum case) with one-sided constant error; both algorithms compute function $f$. Secondly, we show that for all total Boolean functions $f$ holds $R_0(f)=O(R_2(f)^2 \log N)$, where $R_0(f)$ and $R_2(f)$ are randomized zero-sided (a.k.a Las Vegas) and two-sided (a.k.a. Monte Carlo) error query complexities.
Reanalysis, compatibility and correlation in analysis of modified antenna structures

A simple computational procedure is synthesized to process changes in the microwave-antenna pathlength-error measure when there are changes in the antenna structure model. The procedure employs structural modification reanalysis methods combined with new extensions of correlation analysis to provide the revised rms pathlength error. Mainframe finite-element-method processing of the structure model is required only for the initial unmodified structure, and elementary postprocessor computations develop and deal with the effects of the changes. Several illustrative computational examples are included. The procedure adapts readily to processing spectra of changes for parameter studies or sensitivity analyses.
A quasar discovered at redshift 6.6 from Pan-STARRS1

National Aeronautics and Space Administration [NNX08AR22G]; National Science Foundation [AST-1238877]; Ministry of Science and Technology (MoST) of Taiwan through grant National Science Council (NSC) [103-2112-M-007-002-MY3, 105-2112-M-007-003-MY3]; MoST of Taiwan [NSC 100-2112-M-001-001-MY3, 104-2112-M-001-034-, 105-2112-M-001-024-]
Parabolic Equation Methods for Electromagnetic Wave Propagation

This book is the first to present the application of parabolic equation methods in electromagnetic wave propagation. These powerful numerical techniques have become the dominant tool for assessing clear-air and terrain effects on radiowave propagation and are growing increasingly popular for solving scattering problems. The book gives the mathematical background to parabolic equation modelling and describes simple parabolic equation algorithms before progressing to more advanced topics such as domain truncation, the treatment of impedance boundaries and the implementation of very fast hybrid methods combining ray-tracing and parabolic equation techniques. The last three chapters are devoted to scattering problems, with application to propagation in urban environments and to radar cross section computation. This book will prove useful to scientists and engineers who require accurate assessment of diffraction and ducting on radio and radar systems. Its self-contained approach should also make it particularly suitable for graduate students and other researchers interested in radiowave propagation scattering.
Four Metal-poor Stars in the Sagittarius Dwarf Spheroidal Galaxy

We present the metallicities and carbon abundances of four newly discovered metal-poor stars with −2.2 < [Fe/H] < −1.6 in the Sagittarius dwarf spheroidal galaxy. These stars were selected as metal-poor member candidates using a combination of public photometry from the SkyMapper Southern Sky Survey and proper-motion data from the second data release from the Gaia mission. The SkyMapper filters include a metallicity-sensitive narrowband v filter centered on the Ca ii K line, which we use to identify metal-poor candidates. In tandem, we use proper-motion data to remove metal-poor stars that are not velocity members of the Sagittarius dwarf spheroidal galaxy. We find that these two data sets allow for efficient identification of metal-poor members of the Sagittarius dwarf galaxy to follow up with further spectroscopic study. Two of the stars we present have [Fe/H] < −2.0, which adds to the few other such stars currently identified in the Sagittarius dwarf galaxy that are likely not associated with the globular cluster M54, which resides in the nucleus of the system. Our results confirm that there exists a very metal-poor stellar population in the Sagittarius dwarf galaxy. We find that none of our stars can be classified as carbon-enhanced metal-poor stars. Efficiently identifying members of this population will be helpful to further our understanding of the early chemical evolution of the system.
Quantifying the suppression of the (un)-obscured star formation in galaxy cluster cores at 0.2≲ z ≲0.9

We quantify the star formation (SF) in the inner cores (⁠R/R200 ≤0.3) of 24 massive galaxy clusters at 0.2≲ z ≲0.9 observed by the Herschel Lensing Survey and the Cluster Lensing and Supernova survey with Hubble. These programmes, covering the rest-frame ultraviolet to far-infrared regimes, allow us to accurately characterize stellar mass-limited (⁠M∗>1010 M⊙) samples of star-forming cluster members (not)-detected in the mid- and/or far-infrared. We release the catalogues with the photometry, photometric redshifts, and physical properties of these samples. We also quantify the SF displayed by comparable field samples from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey. We find that in intermediate-z cluster cores, the SF activity is suppressed with respect the field in terms of both the fraction (⁠F⁠) of star-forming galaxies (SFGs) and the rate at which they form stars (⁠SFR and sSFR=SFR/M∗⁠). On average, the F of SFGs is a factor ∼2 smaller in cluster cores than in the field. Furthermore, SFGs present average SFR and sSFR typically ∼0.3 dex smaller in the clusters than in the field along the whole redshift range probed. Our results favour long time-scale quenching physical processes as the main driver of SF suppression in the inner cores of clusters since z ∼0.9, with shorter time-scale processes being very likely responsible for a fraction of the missing SFG population.
Power Laws are Boltzmann Laws in Disguise

Using a model based on generalised Lotka Volterra dynamics together with some recent results for the solution of generalised Langevin equations, we show that the equilibrium solution for the probability distribution of wealth has two characteristic regimes. For large values of wealth it takes the form of a Pareto style power law. For small values of wealth, (w less then wmin) the distribution function tends sharply to zero with infinite slope. The origin of this law lies in the random multiplicative process built into the model. Whilst such results have been known since the time of Gibrat, the present framework allows for a stable power law in an arbitrary and irregular global dynamics, so long as the market is `fair', i.e., there is no net advantage to any particular group or individual. We show for our model that the relative distribution of wealth follows a time independent distribution of this form even thought the total wealth may follow a more complicated dynamics and vary with time in an arbitrary manner. In developing the theory, we draw parallels with conventional thermodynamics and derive for the system the associated laws of `econodynamics' together with the associated econodynamic potentials. The power law that arises in the distribution function may then be identified with new additional logarithmic terms in the familiar Boltzmann distribution function for the system. The distribution function of stock market returns for our model, it is argued, will follow the same qualitative laws and exhibit power law behaviour.
A novel hospital-at-home model for patients with COVID-19 built by a team of local primary care clinics and clinical outcomes: A multi-center retrospective cohort study

Background Hospital-at-home (HaH) care has been proposed as an alternative to inpatient care for patients with COVID-19. Previous reports were hospital-led and involved patients triaged at the hospitals. To reduce the burden on hospitals, we constructed a novel HaH care model organised by a team of local primary care clinics. Methods We conducted a multi-center retrospective cohort study of the COVID-19 patients who received our HaH care from Jan 1st to Mar 31st, 2022. Patients who were not able to be triaged for the need for hospitalization by the Health Center solely responsible for the management of COVID-19 patients in Osaka City were included. The primary outcome was receiving medical care beyond the HaH care defined as a composite outcome of any medical consultation, hospitalization, or death within 30 days from the initial treatment. Results Of 382 eligible patients, 34 (9%) were triaged for hospitalization immediately after the initial visit. Of the remaining 348 patients followed up, 37 (11%) developed the primary outcome, while none died. Obesity, fever, and gastrointestinal symptoms at baseline were independently associated with an increased risk of needing medical care beyond the HaH care. A further 129 (37%) patients were managed online alone without home visit, and 170 (50%) required only one home visit in addition to online treatment. Conclusions The HaH care model with a team of primary care clinics was able to triage patients with COVID-19 who needed immediate hospitalization without involving hospitals, and treated most of the remaining patients at home.
Ranking by the Rough Approximation of a Preference Relation for an Extrusion Process - a Robustness Study

In this paper an extrusion process example is studied to illustrate a new methodology in the field of decision engineering, which is based on the rough set approach. Rough sets are used to aid the Decision Maker in choosing the best point in the Pareto’s region, which is the zone of the non-dominated solutions. The rough set approach allows us to make a rough approximation of a preference relation on a sample of experimental points chosen from the Pareto set. These approximations are done to induce the decision rules, which can be afterwards applied on whole sets of the potential points. To give the final recommendation the concept of technical robustness is suggested.
Mental health and wellbeing of border security personnel: scoping review

Abstract Background Whilst the wellbeing of law enforcement personnel has been widely researched, border security personnel as a discrete group appear to be far less discussed, despite their roles frequently exposing them to potentially traumatic and challenging events such as contact with criminals or witnessing personal tragedies due to trafficking or smuggling. Aims This scoping review aimed to explore existing literature to better understand the mental health of border security personnel and the factors affecting their wellbeing. Methods Four electronic databases and grey literature were systematically searched for studies relevant to the review’s aims. Following the extraction of relevant data from each study, thematic analysis was used to synthesize findings. Results Thirteen studies included relevant data and were included in the review, identifying stressors including poor management; fatigue; negative public attitudes; inadequate staffing levels, resources, and training; poor opportunities for promotion; low pay; work overload; dangerous working environments; and work-related moral dilemmas. Conclusions The review found that there has been little academic attention paid to border security personnel as a specific branch of law enforcement. Many of the stressors identified in this review are those also reported by law enforcement generally, although negative attitudes from the public and exposure to moral dilemmas appear to be more relevant for border security staff. Directly addressing work-related stress (e.g. by fostering a supportive organizational culture, addressing mental health stigma, and encouraging help-seeking) may be useful in enhancing the resilience of border security personnel.
Implementation of a navigation system: Economic verification in a local hospital

Healthcare, like other industries, is increasingly using smart technologies, which also include intelligent/smart wayfinding navigation. The focus of this article, as part of the research project (its second step), was to analyze the economic effectiveness of the introduction of the wayfinding system in a local hospital in the Czech Republic. In the first phase/step of the project, possible variants of the solution were identified, verification of possible functioning, and a questionnaire survey was conducted among employees and patients regarding the waste of time in search of destination and preferences of various forms of navigation. Based on the above, it was decided to develop our own mobile application. To determine the effectiveness of this method of implementation of the new system, economic verification was used by the cost-benefit analysis method. Although the use of this method has not been required in the implementation of funded projects within the European Union since 2021, it was chosen for clarifying the pros and cons in many both investment and non-investment projects. In addition to the net present value calculation, the benefit cost ratio, profitability index, and payback period were used for evaluation. The time saving of medical staff, calculated on the basis of a questionnaire survey in the hospital (the first step of the project), was used as a benefit. The costs used were the salaries paid out in the research project, the investment, and the operating costs over the lifetime of the navigation system, which is estimated at eleven years. Using the above indicators, the implementation of the navigation system was found to be effective, despite the initial high costs. Based on these results, as part of the third step of the project, the navigation system will be implemented in the given hospital—the testing phase was taking place in the last quarter of 2021, and the full implementation is expected during the 2022.
Spectroscopic abundance analyses of the 3He stars HD 185330 and 3 Cen A

Abundances of 21 elements in two 3He stars HD 185330 and 3 Cen A have been analysed relative to the well studied sharp-lined B3 V star iota Her. Six elements (P, Ti, Mn, Fe, Ni, and Br) are over-abundant in these two peculiar stars, while six elements (C, O, Mg, Al, S, and Cl) are under-abundant. Absorption lines of the two rarely observed heavy elements Br II and Kr II are detected in both stars and these elements are both over-abundant. The centroid wavelengths of the Ca II infrared triplet lines in these stars are red-shifted relative to those lines in iota Her and the presence of heavy isotopes of Ca (mass number 44 - 46) in these two stars are confirmed. In spite of these similarities, there are several remarkable differences in the abundance pattern between these two stars. N is under-abundant in HD 185330, as in many Hg-Mn stars, while it is significantly over-abundant in 3 Cen A. P and Ga are both over-abundant in 3 Cen A, while only P is over-abundant and no trace of absorption line of Ga II can be found in HD 185330. Large over-abundances of Kr and Xe are found in both stars, while the abundance ratios Kr / Xe are significantly different between them (-1.4 dex in HD 185330 and +1.2 dex in 3 Cen A). Some physical explanations are needed to account for these qualitative differences.
Accuracy of intraocular lens calculations in eyes with keratoconus

Recently, 2 keratoconus-adjusted formulas, Kane keratoconus and Barrett True-K for keratoconus, were introduced to calculate IOL power in patients with keratoconus. These formulas improve the prediction accuracy in patients with keratoconus. Purpose: To compare the prediction accuracy of the Barrett True-K for keratoconus with standard formulas (SRK/T, Barrett Universal II, and Kane) and the Kane keratoconus formula. Setting: Shaare Zedek Medical Center, Jerusalem, Israel, and University Eye Clinic, Maastricht, the Netherlands. Design: Multicenter retrospective case series. Methods: Eyes with stable keratoconus undergoing cataract surgery were included. The predicted refractions were calculated for SRK/T, Barrett Universal II, Barrett True-K for keratoconus (predicted and measured), Kane, and Kane adjusted for keratoconus formulas. Primary outcomes were prediction error (PE), absolute error (AE), and percentage of eyes with PE ±0.25 diopters (D), ±0.50 D, and ±1.00 D. Subgroup analyses were performed based on the severity of the keratoconus. Results: 57 eyes were included in the study. The PE was not significantly different from zero for SRK/T, Barrett True-K (predicted and measured), and Kane keratoconus formulas (range 0.09 to 0.22 D, P > .05). The AE of Barrett True-K predicted (median 0.14 D) and Barrett True-K measured (median 0.10 D) were significantly lower from Barrett Universal II (median 0.47 D) and Kane (median 0.50 D), P < . 001. Conclusions: The Barrett True-K formulas for keratoconus had higher prediction accuracy as compared with new generation formulas and a similar prediction accuracy as compared with the Kane keratoconus formula.
Emerging and re-emerging KPC-producing hypervirulent Pseudomonas aeruginosa ST697 and ST463 between 2010 and 2021

ABSTRACT Carbapenem-resistant Pseudomonas aeruginosa (CRPA) has been a major threat to human health due to its increased morbidity and mortality in clinical settings. Carbapenemase genes are less frequently found in CRPA compared with carbapenem-resistant Enterobacterales, of which carbapenemase producers are common. In this study, we identified 11 bla KPC-2-harbouring P. aeruginosa isolates from 139 carbapenemase-insensitive P. aeruginosa isolates collected between 2010 and 2021 in a tertiary hospital in China. Nine isolates belonged to ST697, while the other two were ST463. The antibiotic susceptibility testing showed that all the isolates were multidrug resistant, including resistance to imipenem, meropenem, ceftazidime, and tigecycline. Patients with Klebsiella pneumoniae carbapenemase-2 (KPC-2)-producing P. aeruginosa infections were mostly associated with complicated diseases and prolonged hospital stay, with 30% deterioration. The whole-genome sequencing analysis showed that these isolates carried multiple antibiotic resistance genes and virulence genes, and the KPC-2 genetic elements were highly related in ST697 isolates. The complete sequencing of ST697 isolate SE5416 showed that the harbouring of bla KPC-2 resulted from complex transposition and homologous recombination of an IncpRBL16 plasmid and other mobile elements. The Galleria mellonella infection model experiment showed that these KPC-2-producing P. aeruginosa–infected larvae had low survival rates and high virulence. The present study revealed the shifting of CRPA from ST697 to ST463 in East China; ST463 had higher drug resistance, posing greater challenges for clinical management.
Cloud-scale ISM Structure and Star Formation in M51

We compare the structure of molecular gas at 40 pc resolution to the ability of gas to form stars across the disk of the spiral galaxy M51. We break the PAWS survey into 370 pc and 1.1 kpc resolution elements, and within each we estimate the molecular gas depletion time ( ), the star-formation efficiency per free-fall time ( ), and the mass-weighted cloud-scale (40 pc) properties of the molecular gas: surface density, Σ, line width, σ, and , a parameter that traces the boundedness of the gas. We show that the cloud-scale surface density appears to be a reasonable proxy for mean volume density. Applying this, we find a typical star-formation efficiency per free-fall time, , lower than adopted in many models and found for local clouds. Furthermore, the efficiency per free-fall time anti-correlates with both Σ and σ, in some tension with turbulent star-formation models. The best predictor of the rate of star formation per unit gas mass in our analysis is , tracing the strength of self-gravity, with . The sense of the correlation is that gas with stronger self-gravity (higher b) forms stars at a higher rate (low ). The different regions of the galaxy mostly overlap in as a function of b, so that low b explains the surprisingly high found toward the inner spiral arms found by Meidt et al. ().