Choice Of Definition Research Articles

Unveiling social disparities in later life: Income’s Impact on mortality among the elderly in Italy

Abstract Background Income is an important predictor of adult mortality, as a proxy of living conditions, capability and access to health services. Previous studies show that mortality decreases by increasing income. In Italy, studies at a national level are missing. This study aims to investigate inequalities in mortality by income in Italy. Methods The analysis is based on the integration of the National Population Register (comprising the resident population as of Dec 31, 2018, and deaths in 2019) and the Income Statistical Register (representing perceived income during 2018). This integration enabled the availability of information on age, sex, residence, education, income, and vital status at the individual level for 13 million people aged 65 or above. Individuals were categorized according to their individual disposable income quintiles both before and after disability benefits. Inequalities by income are assessed by mortality rate ratios (MRR) estimated using negative binomial regression models controlling for demographic and socioeconomic features. The study is carried out within the Next Gen EU-funded project “Age-It Ageing well in an ageing society” (PE0000015), NRRF, M4.C2, Intervention 1.3. Results Considering income net of disability benefits, lower income levels are associated with higher mortality rates compared to the highest income level, for both sexes. Inequalities are more marked for men. The highest excess was observed for individuals with the lowest income (male MRR=1.65, 95%CI: 1.6-1.71; female MRR=1.43, 95%CI: 1.38-1.48). The excess decreases with increasing income. Conclusions The observed relationships between income and mortality are crucial for targeting policies to reduce health inequalities and promote the well-being of the elderly, the goal of which should be to improve access to social and health care and develop supportive policies for the most disadvantaged people. Further research will be devoted to the use of household income for individuals. Key messages • For the elderly, lower income levels are associated with higher mortality, with wider disparities in men. • The choice of definition of income is essential for an accurate assessment of the association between income and mortality.

Quantification of the prevalence of harms in healthcare related to drug treatment: reflections regarding the use of definitions developed for other settings to estimate the magnitude of the problem.

The prevalence of harms in healthcare related to drug treatment is often quantified using terms developed for pharmacovigilance and pharmaceutical care. In this overview, we guide through the definitions and the settings for which they were developed, with the underlying intention to facilitate the interpretation of hitherto available research intended to contribute information regarding the magnitude of the problem in healthcare and to provide guidance for future research. To start, the regulatory/academic definitions of an adverse drug reaction (ADR) and a drug-related problem (DRP) are considerably broader than a literal interpretation would suggest. ADRs are defined for the pharmacovigilance setting, and for drug safety reasons the opposite of the benefit of the doubt rules; if it cannot be excluded that the medication has caused or contributed to an event, it will be a suspected ADR. DRPs represent the pharmaceutical care setting where every aspect is included that could potentially be problematic; a manifested problem is not required. When quantifying the prevalence of harms related to drug treatment in the healthcare setting, however, it may not be considered reasonable to count every circumstance that could possibly be an ADR or everything that could potentially be problematic. Therefore, definitions developed for the pharmacovigilance and the pharmaceutical care settings are not fully applicable to estimate the magnitude of drug treatment problems in healthcare. Proposed guidance for the future includes cautious interpretation of research results, as well as a conscious choice of definitions according to purpose and tempered reporting in research.

8479 A Challenging Case of Hypercortisolism in an Adult Patient With McCune Albright Syndrome

Abstract Disclosure: P. Kesavan Chary: None. S. Jasim: None. Background: McCune Albright Syndrome (MAS) is a rare genetic disorder that occurs due to a spontaneous post-zygotic missense mutation in the GNAS gene resulting in activating gain of function mutations in G-proteins. MAS classically presents as a triad of café-au-lait skin pigmentation, fibrous dysplasia of bone, and precocious puberty. However, continuous autonomous stimulation of endocrine glands can also result in various other endocrinopathies. We present a rare case of hypercortisolism due to bilateral multinodular adrenal hyperplasia (BMAH) in an adult patient with MAS. Case Report: A 38 year old female had MAS, clinically manifested by precocious puberty, renal phosphate wasting with rickets and osteomalacia, fibrous dysplasia of bone with history of multiple fractures, growth hormone excess, and multinodular thyroid status-post total thyroidectomy. A surveillance CT abdomen showed bilateral (right 3.8 x 1.3 cm and left 1.0 x 0.9 cm) adrenal adenomas with low intrinsic attenuation and washout. On diagnosis, the patient had an AM cortisol of 32.5 ug/dL (6.2-19.4 ug/dL) after a low-dose dexamethasone suppression test (DST), and an AM cortisol of 27.3 ug/dL after a high-dose DST. Late night salivary cortisol was 0.518 ug/dL (<0.010-0.090 ug/dL), 24-hour urine cortisol was 78 ug/24hrs (6-42 ug/24hrs), and ACTH was <1.5 pg/mL (7.2-63.3 pg/mL). The patient was initially asymptomatic and monitored for a few months, but subsequently developed easy bruising, recurrent skin infections, and irritability. The patient declined surgical intervention and was initiated on Osilodrostat. Shortly after medication initiation, she was hospitalized for perforated diverticulitis, hypokalemia, and hypomagnesemia. During hospitalization, AM Cortisol was 49 mcg/dL (4.8-19.5 mcg/dL) and 24-hour urine cortisol was 1023 mcg/24hrs (normal range 3.5-45 mcg/24hrs; the patient’s level prior to admission was 170-190 mcg/24hrs). Osilodrostat was held and the patient was initiated on Etomidate infusion. Once plasma cortisol levels normalized, she resumed Osilodrostat prior to discharge. The patient subsequently tried multiple medical therapy options before undergoing a bilateral adrenalectomy as a definitive treatment choice. Conclusion: The gain of function mutations in MAS result in autonomous endocrine gland function that can manifest clinically as various endocrinopathies. While the most common endocrinopathies in MAS are precocious puberty, hyperthyroidism, and pituitary dysfunction, active surveillance is critical to monitor for less common presentations such as hypercortisolism. This is the first report of adrenal Cushing’s in an adult patient with MAS. Presentation: 6/3/2024

A hierarchy of metabolite exchanges in metabolic models of microbial species and communities.

The metabolic network of an organism can be analyzed as a constraint-based model. This analysis can be biased, optimizing an objective such as growth rate, or unbiased, aiming to describe the full feasible space of metabolic fluxes through pathway analysis or random flux sampling. In particular, pathway analysis can decompose the flux space into fundamental and formally defined metabolic pathways. Unbiased methods scale poorly with network size due to combinatorial explosion, but a promising approach to improve scalability is to focus on metabolic subnetworks, e.g., cells' metabolite exchanges with each other and the environment, rather than the full metabolic networks. Here, we applied pathway enumeration and flux sampling to metabolite exchanges in microbial species and a microbial community, using models ranging from central carbon metabolism to genome-scale and focusing on pathway definitions that allow direct targeting of subnetworks such as metabolite exchanges (elementary conversion modes, elementary flux patterns, and minimal pathways). Enumerating growth-supporting metabolite exchanges, we found that metabolite exchanges from different pathway definitions were related through a hierarchy, and we show that this hierarchical relationship between pathways holds for metabolic networks and subnetworks more generally. Metabolite exchange frequencies, defined as the fraction of pathways in which each metabolite was exchanged, were similar across pathway definitions, with a few specific exchanges explaining large differences in pathway counts. This indicates that biological interpretation of predicted metabolite exchanges is robust to the choice of pathway definition, and it suggests strategies for more scalable pathway analysis. Our results also signal wider biological implications, facilitating detailed and interpretable analysis of metabolite exchanges and other subnetworks in fields such as metabolic engineering and synthetic biology.

Assessment of Suitable Growth Condition of Salvinia spp. for Sustainability of Floating Agriculture to Mitigate Climate Change Challenges on Crop Cultivation

Floating agriculture is an indigenous cultivation practice in the southern waterlogged areas of Bangladesh. Water hyacinth and other macrophytes were utilized in this agricultural method to prepare the floating bed. Among the numerous macrophytes used as mulch in floating beds, Salvinia spp. is a common species. To meet the local farmer's demand, it is necessary to improve the growth rates of these macrophytes so that they can be available year-round for preparing floating beds. For this purpose, an experiment was conducted to assess the growth conditions of Salvinia spp. under various nutritional media. Salvinia molesta and Salvinia cucullata were cultivated in four healthy media to carry out the experiment. The experimental design used in the present investigation was a split-plot arrangement in a Randomized Block Design (RBD), where four nutrients (NO3-; PO43-; NH4+ and Urea) were assigned to the main plots, while five different concentrations of nutrient (0, 1, 5, 10 and 15 mM) were given to the sub-plots. Salvinia spp. growth was examined in terms of morphological and physiological responses and the distribution of nutrients. The highest relative growth rate (RGR) and biomass production (g DW) were found in the medium with one mM and five mM PO43- in the case of S. molesta and one mM NH4+ in the case of S. cucullata. It was also observed that the plant growth rate became suppressed when this macrophyte grew above the 5mM of nutrient concentration, and this suppressed condition turned into a toxic state when the organic nutrient concentration reached a concentration of 15 mM or above. In the case of Urea, this harmful condition starts with a concentration of 5 mM or more for S. molesta and any concentration for S. cucullata.Nonetheless, very few variations were found in how various plant tissues and species absorbed mineral concentrations. The overall findings from this experiment indicate that both PO43- and NH4+ concentrations of 1 mM and 5 mM are comparatively more suitable than NO3- and Urea for the growth and multiplication of Salvinia spp. However, more research is required in addition to varying the quantities of phosphate and ammonium to make a definitive choice. J. of Sci. and Tech. Res. 5(1): 53-62, 2023

Identification of surface urban heat versus cool islands for arid cities depends on the choice of urban and rural definitions

The urban heat island (UHI) effect in arid cities can be small or even negative, the latter known as the urban cool island (UCI) effect. Differences in defining urban and rural areas can introduce uncertainties in detecting UHI or UCI, especially when the UHI signal is small. Here, we compared the surface UHI intensity (SUHII) estimated by a dozen different methods (with multiple urban and/or rural definitions) across 104 arid cities globally, providing a comprehensive evaluation of the uncertainty in SUHII estimates. Results show that the absolute difference in annual average SUHII (∆SUHII) among methods exceeded 1 °C in about half of the arid cities during both daytime and nighttime. The overall annual mean ∆SUHII for all arid cities was 1.35 °C during daytime and 1.03 °C at night. The uncertainty arising from simultaneous variations in urban and rural definitions was generally higher than that resulting from their individual changes. It was observed that, with varying definitions of urban and rural areas, nearly 50 % of arid cities experienced a sign reversal in daytime SUHII estimates, while approximately 15 % exhibited a sign reversal in nighttime SUHII. Variations in urban-rural differences in surface properties, such as vegetation index and albedo, due to differing urban and rural definitions, contributed strongly to the observed SUHII uncertainties. Overall, our results offer new insights into the ongoing debate on heat and cold islands in arid cities, emphasizing a critical need to standardize SUHII estimation frameworks.

Learning the optimal power flow: Environment design matters

To solve the optimal power flow (OPF) problem, reinforcement learning (RL) emerges as a promising new approach. However, the RL-OPF literature is strongly divided regarding the exact formulation of the OPF problem as an RL environment. In this work, we collect and implement diverse environment design decisions from the literature regarding training data, observation space, episode definition, and reward function choice. In an experimental analysis, we show the significant impact of these environment design options on RL-OPF training performance. Further, we derive some first recommendations regarding the choice of these design decisions. The created environment framework is fully open-source and can serve as a benchmark for future research in the RL-OPF field.

Who funds zombie firms: Banks or non-banks?

Analyses of zombie firms have emphasized the role of bank financing as the reason for zombie survival. This conclusion was made despite no comparative analysis of the sources of external finance for zombie firms. This paper provides the first analysis of that sort using Finnish data. Banks are not found to fund zombie firms by more than other types of funders when shares of the credit market are taken into account. Among different types of funding sources, only the relationship between equity funding and zombie status is found to be statistically significant. While bank funding is found to be associated with a longer zombie lifetime, equity funders are found to prolong zombie lifetime by greater extent than other sources. The choice of zombie definition - of which there are many in the literature - is not uncontentious and plays a role in determining the economic significance of coefficient estimates.

Zoning of Degraded Areas Suitable for Implementation of Renewable Energy Generation Systems: Systematic Review

Objective: The objective of this study is to investigate and carry out a systematic review of the literature, with the aim of delving deeper into the topic of zoning and selection of areas for the implementation of renewable energy generating plants. Theoretical Framework: In this topic, the main concepts and theories that underpin the research are presented. The elaboration of the research protocol in four stages: elaboration of questions, choice of databases, definition of the search strategy and inclusion/exclusion criteria, providing a solid basis for understanding the context of the investigation. Method: The methodology adopted for this research comprises the choice of databases and definition of the search string based on the research protocol. Data collection was made by searching Scopus, Science Direct, Web of Science and Energy Citations Database - OSTI. Results and Discussion: The results obtained revealed that 309 studies met the research protocol, of which only 29 studies, after reading the abstract, were ready for the full article reading stage. Seven of these were accepted as relevant to the objective, being classified as accepted and participating in the information gathering to meet the proposed objective. Research Implications: The practical and theoretical implications of this research are discussed, providing insights into how the results can be applied or influence practices in the field of georeferencing. These implications may include public and private enterprises that aim for a less environmentally aggressive methodology for selecting sites for renewable energy generation. Originality/Value: This study contributes to the literature by showing the most relevant points and the main gaps in current selection methodologies. The relevance and value of this research are highlighted by representing a new way of thinking about choosing new locations for power plants.

The Universality of Functions in the Sciences at Large and in Computing

Universality of a concept here means wide conceptual and practical usefulness in mathematics and applications. The function concept owes its universality to simplicity, generality, and powerful algebraic properties. Advantages proven in the sciences at large significantly benefit computing science as well. Universality critically depends on the definitional choices. The first half of this article shows that a “function” in the sense prevalent throughout the sciences, namely, as fully specified by its domain and its values , entails the characteristics that most contribute to universality. This link is clarified by some less well-understood aspects, including the role of function types as partial specifications, the ramifications of having composition defined for any pair of functions, and unification by capturing various notions not commonly seen as functions. Simple but representative examples are given in diverse areas, mostly computing. When a codomain appears at all in basic textbooks, it mostly involves a self-contradicting definition, corrected by the labeled function variant. Either way, it severely reduces universality, especially for composition. Yet, the axiomatization of category theory common in theoretical computing science offers no other choice. The second half explores how waiving one axiom generalizes category theory to include a wider variety of concepts, primarily the conventional function variant. It is also shown how this can be done unobtrusively for typical categorical notions, such as products, coproducts, functors, natural transformations, adjunctions, Galois connections, and auxiliary concepts, illustrated by example definitions and technical comments. Allowing the familiar function variant renders category theory more appealing to a wider group of scientists. A lesson for mathematics in general is Rogaway’s maxim: “Your definitional choices should be justified!”.

Consciously stochastic in preference reversals

Stochastic choice, the act of choosing differently in repeated decisions, can be a conscious decision made by individuals who are aware of their inability to make a definitive choice. To examine the prevalence and implications of conscious stochastic choice, we developed a novel method and implemented it in a preference reversal experiment: In each valuation choice between the bet and a varying reference option, subjects could either pay a small cost to select a specific option or opt for a free randomization choice where a computer randomly selects an option. Our findings revealed that the majority of subjects exhibited conscious stochastic choice, and further that their choices were significantly affected by the elicitation procedures.

Graded decisions in the human brain

Decision-makers objectively commit to a definitive choice, yet at the subjective level, human decisions appear to be associated with a degree of uncertainty. Whether decisions are definitive (i.e., concluding in all-or-none choices), or whether the underlying representations are graded, remains unclear. To answer this question, we recorded intracranial neural signals directly from the brain while human subjects made perceptual decisions. The recordings revealed that broadband gamma activity reflecting each individual’s decision-making process, ramped up gradually while being graded by the accumulated decision evidence. Crucially, this grading effect persisted throughout the decision process without ever reaching a definite bound at the time of choice. This effect was most prominent in the parietal cortex, a brain region traditionally implicated in decision-making. These results provide neural evidence for a graded decision process in humans and an analog framework for flexible choice behavior.

How big is a boulder? The importance of boulder definition choice in earth science research and river management

AbstractBoulders are globally widespread and influence processes across many landscapes including hillslopes, coasts, rivers and extra‐terrestrial settings. Boulders are described as particles, sufficiently large, that they have a disproportionate effect on the surrounding landscape. Moving beyond this conceptual definition, however, requires a somewhat arbitrary decision of how to define a minimum boulder size. The implications of boulder definition on study findings are rarely considered. We investigate the suitability of five boulder definitions, two based on fixed sizes: (1) 0.26 m and (2) 1 m, and three definitions which vary based on system characteristics: (3) grain mobility, (4) grain protrusion and (5) surface grain size distribution (> 84th percentile, D84). We consider the impact of definition on calculated boulder metrics, and, for the >1m and >D84 definitions, their association with channel and catchment characteristics across 20 boulder‐bed streams in northern Sweden. We also surveyed river managers responsible for restoring these rivers, to gain a practitioner insight on boulder size definition. We found that boulder definition matters; for metrics relating to the number or density of boulders, the >D84 and >1m size definitions were negatively correlated. Surveys indicated the importance of communicating boulder definition. We conclude that, whilst the best choice of boulder size definition will vary based on the questions of interest and techniques employed, evaluating the implications of the chosen boulder size definition and communicating the reasoning behind boulder definition choice is crucial.

Energy-related uncertainty and international stock market volatility

This paper predicts the daily return volatility of 28 advanced and developing stock markets using monthly metrics of the corresponding country and global energy-related uncertainty indexes (EUIs) recently proposed in the literature. Using data in their “natural” frequencies to avoid aggregation bias, the results show that country-specific and global EUIs have predictive powers for stock returns volatility for the in-sample periods, with increased levels of EUIs exhibiting the tendency to heighten volatility. This predictability also withstands various out-of-sample forecast horizons, implying that EUI is a statistically relevant predictor in the out-of-sample analysis. The forecast precision of the GARCH-MIDAS model is improved by incorporating global EUIs relatively more than country-specific EUIs. The robustness of the findings with respect to the choice of EUI and sample definition is further confirmed. The outcomes have important policy implications for the concerned stakeholders who are concerned with stability in the global financial system and economy.

Quantifying the impact of hospital catchment area definitions on hospital admissions forecasts: COVID-19 in England, September 2020–April 2021

BackgroundDefining healthcare facility catchment areas is a key step in predicting future healthcare demand in epidemic settings. Forecasts of hospitalisations can be informed by leading indicators measured at the community level. However, this relies on the definition of so-called catchment areas or the geographies whose populations make up the patients admitted to a given hospital, which are often not well-defined. Little work has been done to quantify the impact of hospital catchment area definitions on healthcare demand forecasting.MethodsWe made forecasts of local-level hospital admissions using a scaled convolution of local cases (as defined by the hospital catchment area) and delay distribution. Hospital catchment area definitions were derived from either simple heuristics (in which people are admitted to their nearest hospital or any nearby hospital) or historical admissions data (all emergency or elective admissions in 2019, or COVID-19 admissions), plus a marginal baseline definition based on the distribution of all hospital admissions. We evaluated predictive performance using each hospital catchment area definition using the weighted interval score and considered how this changed by the length of the predictive horizon, the date on which the forecast was made, and by location. We also considered the change, if any, in the relative performance of each definition in retrospective vs. real-time settings, or at different spatial scales.ResultsThe choice of hospital catchment area definition affected the accuracy of hospital admission forecasts. The definition based on COVID-19 admissions data resulted in the most accurate forecasts at both a 7- and 14-day horizon and was one of the top two best-performing definitions across forecast dates and locations. The “nearby” heuristic also performed well, but less consistently than the COVID-19 data definition. The marginal distribution baseline, which did not include any spatial information, was the lowest-ranked definition. The relative performance of the definitions was larger when using case forecasts compared to future observed cases. All results were consistent across spatial scales of the catchment area definitions.ConclusionsUsing catchment area definitions derived from context-specific data can improve local-level hospital admission forecasts. Where context-specific data is not available, using catchment areas defined by carefully chosen heuristics is a sufficiently good substitute. There is clear value in understanding what drives local admissions patterns, and further research is needed to understand the impact of different catchment area definitions on forecast performance where case trends are more heterogeneous.

Investigating the Star Formation Rates of Active Galactic Nucleus Hosts Relative to the Star-forming Main Sequence

A fundamental question in galaxy and black hole evolution remains how galaxies and their supermassive black holes have evolved together over cosmic time. Specifically, it is still unclear how the position of X-ray active galactic nucleus (AGN) host galaxies with respect to the star-forming main sequence (MS) may change with the X-ray luminosity (L X) of the AGN or the stellar mass (M ⋆) of the host galaxy. We use data from the XMM-Spitzer Extragalactic Representative Volume Survey (XMM-SERVS) to probe this issue. XMM-SERVS is covered by the largest medium-depth X-ray survey (with superb supporting multiwavelength data) and thus contains the largest sample to date for study. To ensure consistency, we locally derive the MS from a large reference galaxy sample. In our analysis, we demonstrate that the turnover of the galaxy MS does not allow reliable conclusions to be drawn for high-mass AGNs, and we establish a robust safe regime where the results do not depend upon the choice of MS definition. Under this framework, our results indicate that less massive AGN host galaxies ( logM⋆∼9.5–10.5M⊙ ) generally possess enhanced star formation rates compared to their normal-galaxy counterparts while the more massive AGN host galaxies ( logM⋆∼10.5–11.5M⊙ ) lie on or below the star-forming MS. Further, we propose an empirical model for how the placement of an AGN with respect to the MS (SFRnorm) evolves as a function of both M ⋆ and L X.

Coordinating virus research: The Virus Infectious Disease Ontology.

The COVID-19 pandemic prompted immense work on the investigation of the SARS-CoV-2 virus. Rapid, accurate, and consistent interpretation of generated data is thereby of fundamental concern. Ontologies-structured, controlled, vocabularies-are designed to support consistency of interpretation, and thereby to prevent the development of data silos. This paper describes how ontologies are serving this purpose in the COVID-19 research domain, by following principles of the Open Biological and Biomedical Ontology (OBO) Foundry and by reusing existing ontologies such as the Infectious Disease Ontology (IDO) Core, which provides terminological content common to investigations of all infectious diseases. We report here on the development of an IDO extension, the Virus Infectious Disease Ontology (VIDO), a reference ontology covering viral infectious diseases. We motivate term and definition choices, showcase reuse of terms from existing OBO ontologies, illustrate how ontological decisions were motivated by relevant life science research, and connect VIDO to the Coronavirus Infectious Disease Ontology (CIDO). We next use terms from these ontologies to annotate selections from life science research on SARS-CoV-2, highlighting how ontologies employing a common upper-level vocabulary may be seamlessly interwoven. Finally, we outline future work, including bacteria and fungus infectious disease reference ontologies currently under development, then cite uses of VIDO and CIDO in host-pathogen data analytics, electronic health record annotation, and ontology conflict-resolution projects.

An Assessment of the Validity of Damköhler’s Hypotheses for Different Choices of Reaction Progress Variable in Homogenous Mixture Moderate or Intense Low-Oxygen Dilution (MILD) Combustion

The applicability of Damköhler’s hypotheses for homogenous mixture (i.e. constant equivalence ratio) moderate or intense low-oxygen dilution (MILD) combustion processes (with methane as the fuel) has been assessed using three-dimensional direct numerical simulation data with a skeletal mechanism. Two homogeneous MILD combustion cases with different levels of O2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\ ext{O}}}_{2}$$\\end{document} concentration (4.8% and 3.5% by volume) and different turbulence intensities have been investigated to analyse the influence of dilution level, turbulence intensity and the choice of the reaction progress variable definition (i.e. different choices of major species for turbulent burning velocity and flame surface area evaluations) on the applicability of Damköhler’s hypotheses in MILD combustion. It has been found that the normalized volume-integrated burning rate remains of the same order of magnitude as that of the normalized flame surface area only for the reaction progress variable definition based on a species mass fraction which has a Lewis number close to unity (e.g. CH4\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\ ext{CH}}}_{4}$$\\end{document}) but the level of applicability deteriorates when the Lewis number of the species mass fraction, based on which the reaction progress variable is defined, deviates significantly from unity (e.g. CO2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\ ext{CO}}}_{2}$$\\end{document}). Moreover, it has been demonstrated that the flame surface area calculation from the OH mole fraction-based information can lead to significant departures from Damköhler’s first hypothesis. It is also found that the relative magnitudes of normalised volume-integrated burning rate and normalised flame surface area are significantly affected by the level of dilution and the choice of the reaction progress variable definition. Damköhler’s second hypothesis, which provides a relation between the normalised turbulent burning velocity and the ratio of turbulent to molecular diffusivities, has been found to hold in an order of magnitude sense in homogeneous mixture MILD combustion only for the reaction progress variable definition based on species that has a Lewis number close to unity (e.g. CH4\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\ ext{CH}}}_{4}$$\\end{document}) but the level of disagreement increases as the Lewis number of the reaction progress variable deviates significantly from unity (e.g. CO2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\ ext{CO}}}_{2}$$\\end{document}).

Experimental study on monotonic to high-cyclic behaviour of sand-silt mixtures

The naturally deposited soil usually does not consist of pure coarse or fine-grained soil but of a mixture of both. The mechanical behaviour of a saturated fine sand mixed with varying amounts of low-plastic fines was evaluated by monotonic as well as high-cyclic triaxial tests. The test results were used to conclude on the effect of fines content on the critical state, phase transformation line, secant Young’s modulus, the residual strain accumulation as well as strain amplitude during drained cycles of the mixtures in relation to the global void ratio as well as to the equivalent void ratio. It was found that while the choice of void ratio definition is important for the uniqueness of the critical void ratio, both approaches can be used as state variables for the phase transformation line. However, some seemingly contradictive results are found from the drained high-cyclic tests. Eventhough, an increase of the residual strain accumulation with decreasing fines content compared at the same initial equivalent void ratio is rendered by the laboratory data, a unique and on fines content independent relationship between εacc\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\varepsilon ^{\\rm{acc}}$$\\end{document} could be established only with respect to the initial global void ratio.

The mean wall-normal velocity in turbulent boundary layer flows under pressure gradient

Using a combination of proper variable transformation and integral methods, we rigorously derive an analytical formulation for the mean wall-normal velocity in turbulent boundary layers (TBLs) subjected to arbitrary pressure gradients. The accuracy and robustness of this novel formulation are validated extensively through comparisons with two independent sets of numerical simulation data, demonstrating excellent agreement in both near-equilibrium and non-equilibrium TBLs. In addition, the robustness of the analytical formulations to various choices of boundary-layer edge definition is further confirmed in non-equilibrium TBLs. Our formulation includes a streamwise derivative term, which has minimal significance in near-equilibrium TBLs but plays a crucial role in determining the mean wall-normal velocity in non-equilibrium TBLs. Moreover, we investigate the physical significance of the pre-factors associated with the mean wall-normal velocity components, and unveil a close connection between a previously defined pressure gradient parameter and the ratio of these pre-factors in the analytical equation governing the mean wall-normal velocity. The insights gained from the examination of the pre-factors and their connection to the pressure gradient parameter offer valuable knowledge for interpreting and predicting the behaviour of turbulent boundary layers in various practical applications.