Variable Mixture Research Articles

Catalogues of EQ-5D-3L Health-Related Quality of Life Scores for 199 Chronic Conditions and Health Risks for Use in the UK and the USA.

Health-related quality of life (HRQoL) measures are essential in economic evaluation, but sometimes primary sources are unavailable, and information from secondary sources is required. Existing HRQoL UK/US catalogues are based on earlier diagnosis classification systems, amongst other issues. A recently published Danish catalogue merged EQ-5D-3L data from national health surveys with national registers containing patient information on ICD-10 diagnoses, healthcare activities and socio-demographics. To provide (1) UK/US EQ-5D-3L-based HRQoL utility population catalogues for 199 chronic conditions on the basis of ICD-10 codes and health risks and (2) regression models controlling for age, sex, comorbidities and health risks to enable predictions in other populations. UK and US EQ-5D-3L value sets were applied to the EQ-5D-3L responses of the Danish dataset and modelled using adjusted limited dependent variable mixture models (ALDVMMs). Unadjusted mean utilities, percentiles and adjusted disutilities based on two ALDVMMs with different control variables were provided for both countries. Diseases from groups M, G, and F consistently had the smallest utilities and the largest negative disutilities: fibromyalgia (M797), sclerosis (G35), rheumatism (M790), dorsalgia (M54), cerebral palsy (G80-G83), post-traumatic stress disorder (F431), dementia (F00-2), and depression (F32, etc.). Risk factors, including stress, loneliness, and BMI30+, were also associated with lower HRQoL. This study provides comprehensive catalogues of UK/US EQ-5D-3L HRQoL utilities. Results are relevant in cost-effectiveness analysis, for NICE submissions, and for comparing and identifying facets of disease burden.

Enabling QALY estimation in mental health trials and care settings: mapping from the PHQ-9 and GAD-7 to the ReQoL-UI or EQ-5D-5L using mixture models

PurposePatient-reported outcome measures (PROMs) are commonly collected in trials and some care settings, but preference-based PROMs required for economic evaluation are often missing. For these situations, mapping models are needed to predict preference-based (aka utility) scores. Our objective is to develop a series of mapping models to predict preference-based scores from two mental health PROMs: Patient Health Questionnaire-9 (PHQ-9; depression) and Generalised Anxiety Questionnaire-7 (GAD-7; anxiety). We focus on preference-based scores for the more physical-health-focussed EQ-5D (five-level England and US value set, and three-level UK cross-walk) and more mental-health-focussed Recovering Quality-of-Life Utility Index (ReQoL-UI).MethodsWe used trial data from the Improving Access to Psychological Therapies (IAPT) mental health services (now called NHS Talking Therapies), England, with a focus on people with depression and/or anxiety caseness. We estimated adjusted limited dependent variable or beta mixture models (ALDVMMs or Betamix, respectively) using GAD-7, PHQ-9, age, and sex as covariates. We followed ISPOR mapping guidance, including assessing model fit using statistical and graphical techniques.ResultsOver six data collection time-points between baseline and 12-months, 1340 observed values (N ≤ 353) were available for analysis. The best fitting ALDVMMs had 4-components with covariates of PHQ-9, GAD-7, sex, and age; age was not a probability variable for the final ReQoL-UI mapping model. Betamix had practical benefits over ALDVMMs only when mapping to the US value set.ConclusionOur mapping functions can predict EQ-5D-5L or ReQoL-UI related utility scores for QALY estimation as a function of variables routinely collected within mental health services or trials, such as the PHQ-9 and/or GAD-7.

Syn-Bushveld “granite sheets” associated with the Molopo Farms Complex intruding into Transvaal Supergroup strata in southern Botswana

Abstract LA-ICPMS U-Pb isotope analyses are presented for zircons from a thin granite sheet intersected in a borehole drilled into the upper Transvaal Supergroup wall rocks to the Molopo Farms Complex in southern Botswana. Many of the zircons have irregular or angular grain margins, and some have rounded cores. Approximately half of the analysed grains yielded concordant 207Pb/206Pb ages ranging between 2 282 ± 29 and 2 113 ± 16 Ma. Assuming that these grains were inherited from the surrounding upper Transvaal Supergroup sedimentary strata, the youngest zircon age provides a maximum depositional age for these sediments. Importantly, these zircon ages coincide with dates from detrital zircons in upper Transvaal Supergroup strata in the eastern Kaapvaal Craton and in the Magondi Supergroup in western Zimbabwe. Hf isotope analyses of the rounded zircons suggest that these grains were sourced from a variable mixture of an old basement and more juvenile material. A younger age of 2 060 ± 12 Ma was obtained from a single subhedral zircon grain from the granite sheet. This is interpreted as the granite’s emplacement age, making it coeval with the adjacent Molopo Farms Complex that forms part of the Bushveld Large Igneous Province.

Combinations of numerical solutions for prediction of cavitation inception in flows around blades

Investigations of cavitation inception are important for marine engineering because of the assistant jump of flow-induced noise. This inception has been traditionally predicted via model tests, but their results are influenced by the complex multi-zone composition of flows, the diversity of inflows and substantial scale effects. These influences make it highly desirable to supplement or substitute the model tests by computations. As shown in this paper, the physics of cavitation inception can be satisfactory described by 2D or quasi-2D multi-zone computations, whereas the existing solvers for 3D fully turbulent variable density mixtures are not fitted to this physics. On the other hand, a 3D analysis is requested for engineering. Recommendation on the combined employment of two groups of methods for computations of inception of cavitating 3D flows are provided among with the computational examples of such combinations.

76 Combined Exposure to road wear Particles and Diesel Exhaust Particles Induces Enhanced pro-Inflammatory Responses in Cells of the Human Airways

Abstract Ambient particulate matter (PM) is one of the leading environmental mortality risk factors worldwide. PM is not a single entity but consists of a complex and variable mixture of particles from multiple sources. Nevertheless, there is a paucity of experimental studies assessing the potential combinatory effects of different types of particles, and most focus on the effects of individual PM components or mixed PM samples. In the present study, the pro-inflammatory effects of combined exposure to road wear particles and diesel exhaust particles (DEP), two important constituents of traffic-derived PM, were assessed in vitro. Human bronchial epithelial cells (HBEC3-KT) and differentiated THP-1 macrophage-like cells were exposed to road wear particles and two different samples of DEP under submerged conditions, both alone and in combination. Particle-induced release of pro-inflammatory cytokines (CXCL8 and IL-1β) was measured by enzyme-linked immunosorbent assay. The results show that combined exposure to road wear particles and DEP induced enhanced release of pro-inflammatory cytokines compared with the effects of the individual particle samples. The combinatory effects appeared to depend on properties of the DEP samples and also differed between the HBEC3-KT cells and THP-1 macrophage-like cells. This study shows that the effects of combined exposure to different types of particles may surpass the effects anticipated by the effects of the individual particulates. These combinatory effects between types of particles could have implications when assessing measures to reduce PM-induced health effects.

Impact of Market Coverage Strategy with reference to Lulu Hypermarket Muscat

recent competitive scenario, it is important to determine the factor affecting marketing strategy. Especially in retail industry there is a tough competition not only from tradition retailers but e-tailors too. It is necessary for every retailer to assess the impact of current market coverage strategy and ways for achieving an effective market coverage strategy implementation. The specific objectives in research is to “identify the variables for effective market coverage strategy”, “assess the impact of the current market coverage strategy by the lulu hypermarket in Oman” and “Suggest the methods for implementing effective elements for market coverage strategy”. The type is research is both quantitative and qualitative with a mixture of numerical analysis and statistical variables. With questions being distributed as questionnaires to 70 customers and 2 employees with some demographic variables to better segment the market perception based on them. The main focus of our study is on the Muscat region of the sultanate, with convenient sampling being used.

The Impact of Chinese FDI on Zambia's Socio-Economic Development

There has been an increase of Chinese investments in many parts of the globe. According to Bo Li (2016), China’s outward foreign direct investment OFDI stock has grown from $1 Billion in 2004 to more than $30 Billion in 2014. However, there is an ever-growing volume of literature premised on the criticism of the impact of Chinese investment in Africa and other parts of the globe. Many studies have cited China as being after the resources of its host countries without much concern to the effects or benefits to local populations, (James Mayers:2015) and (Reisen and Rielander:2011). This paper made an attempt to explore the impact of Chinese FDI on social economic development focusing on job creation and poverty reduction in Zambia. The study was largely qualitative in nature and adopted a mixture of descriptive and explorative study designs. The study focused on Zambia because of the unique bilateral ties with China which span over decades. Furthermore, many studies done on Chinese FDI usually aggregate all African countries overlooking the differential impact of the source and type of Chinese FDI in Africa which makes it difficult to generalize findings, (Abdoulkadre Ado Zhan Su:2016). While many studies only focus on the economic effects of FDI by stressing on quantitative aspects, this study went further to analyze a mixture of qualitative and quantitative variables within the socio-economic context. This approach was adopted in order to provide a comprehensive analysis and hence a point of departure from other similar studies done on this subject. Less focus was laid on characteristic of FDI which in itself was a delimitation. A number of key conclusions revealed through my findings are that China has made significant investments in different sectors of the economy which have translated into job creation and helped to lift thousands of local people from poverty. However, despite the numerous investments made, jobs created are mostly for unskilled laborers. In addition, although most firms meet the minimum wage requirement, wages still fall below the Basic needs and nutrition basket, (Jesuit Center for Theological Reflections:2022). These are some of the areas of concern which have undermined notable gains. The paper therefore starts by unpacking suppositions surrounding FDI, then makes efforts to disambiguate economic growth from economic development before stressing on the findings and finally drawing conclusion. Keywords: FDI, economic growth, economic development, sustainable development. DOI: 10.7176/JESD/14-10-01 Publication date: May 31 st 2023

The Influence of Nitrogen Applications and Low Rainfall Conditions on Yield of Mixed Grass-Legume Grassland for 2 Years

Mixed-species grassland containing legumes were suggested to increase yield compared to monocultures. Furthermore, some legumes were suggested to be able to sustain growth, even under drought conditions. The first aim of the current study was to measure if multispecies grassland with legumes is also more productive when their N input due to symbiotic N2 fixation is taken into account. Our second aim was to determine the benefit of grass–legume mixtures in terms of dry matter production under naturally occurring drought conditions. Mixed-species grasslands, consisting of monocultures and variable mixtures of (a) Trifolium pratense, (b) Trifolium. repens, (c) Lolium perenne, and (d) a mixture of drought-tolerant grasses (GSWT based), were assessed for their dry matter production over two years with contrasting weather patterns. The legume–grass seeding mixtures received either a fixed (180 kg N ha−1) or adapted N-fertilizer application (0–180 kg N ha−1), with the latter taking the assumed symbiotic N2 fixation by legumes into account. Mixed-species grassland showed improved yield compared to monocultures both in comparably humid and drought-affected years. The benefits of multispecies grass–legume mixtures were considerably more obvious under a fixed but still measurable under an adapted N-fertilizer regime. The species diversity effect appears to be significantly dependent on the additional N supply enabled by legumes’ symbiotic N2-fixation. Legumes and drought-tolerant grasses yielded equally well under drought conditions, although legumes showed major advantages during moderate drought and humid conditions. White and red clover, although both legumes, differed significantly in their persistence under elevated-N and their dry matter production under low-N fertilizer application, but were equal in their tolerance towards drought.

Mapping health assessment questionnaire disability index onto EQ-5D-5L in China.

This research aimed to develop the more accurate mapping algorithms from health assessment questionnaire disability index (HAQ-DI) onto EQ-5D-5L based on Chinese Rheumatoid Arthritis patients. The cross-sectional data of Chinese RA patients from 8 tertiary hospitals across four provincial capitals was used for constructing the mapping algorithms. Direct mapping using Ordinary least squares regression (OLS), the general linear regression model (GLM), MM-estimator model (MM), Tobit regression model (Tobit), Beta regression model (Beta) and the adjusted limited dependent variable mixture model (ALDVMM) and response mapping using Multivariate Ordered Probit regression model (MV-Probit) were carried out. HAQ-DI score, age, gender, BMI, DAS28-ESR and PtAAP were included as the explanatory variables. The bootstrap was used for validation of mapping algorithms. The average ranking of mean absolute error (MAE), root mean square error (RMSE), adjusted R 2 (adjR 2) and concordance correlation coefficient (CCC) were used to assess the predictive ability of the mapping algorithms. According to the average ranking of MAE, RMSE, adjR 2, and CCC, the mapping algorithm based on Beta performed the best. The mapping algorithm would perform better as the number of variables increasing. The mapping algorithms provided in this research can help researchers to obtain the health utility values more accurately. Researchers can choose the mapping algorithms under different combinations of variables based on the actual data.

On the Bivariate Generalized Gamma-Lindley Distribution

ABSTRACT In this research paper, we propose a new class of bivariate distributions called Bivariate Generalized Gamma-Lindley (BGGL) distribution with four parameters. This model is a mixture of independent Gamma random variables and bivariate generalized Lindley distribution. We investigate various properties of the new bivariate distribution such as graphical representation, joint moments and correlation. Furthermore, we derive a measure of entropy of this bivariate distribution. We also derive the distributions of the random variables X 1 + X 2, X 1/(X 1 + X 2), X 1/X 2 and X 1 X 2 as well as the corresponding moment properties when X 1 and X 2 follow the BGGL distribution. Additionally, we address two approximations of the product of the proposed model and assess their goodness of fit. Next, we elaborate the expectation maximization (E.M) algorithm in order to estimate the BGGL model parameters. Finally, we provide two concrete examples to demonstrate the applicability of the results.

Select human milk oligosaccharide supplementation in post‐weanling rats affects metabolism and gut microbiota into adulthood

Feeding infants with human milk versus formula can produce long-lasting benefits, including reduced risk of inflammatory diseases. Most infant formulas do not contain human milk oligosaccharides (HMOs), which are important carbohydrates in human breast milk displaying prebiotic properties. The study's aim was to examine the effect of select HMOs in the post-weaning period. Metabolic and microbial outcomes were measured in female and male rats whose post-weaning diet was supplemented with 3'sialyllactose and 2'-O-fucosyllactose (low dose, 0.75% of each, or high dose, 2% of each). It was determined whether exposure to the HMOs would attenuate metabolic dysfunction associated with a high fat/sucrose (HFS) diet. HMO supplementation resulted in dose-dependent and sex-dependent effects, with the high HMO female group displaying reduced food intake and percentage body fat and an increase in Blautia abundance. Early life HMO supplementation did not prevent the effects of an HFS diet on metabolic outcomes; however, rats that received high dose HMOs followed by the HFS diet were the only HFS group that maintained a measurable abundance of Blautia. This study highlights the potential for HMOs in follow-up infant formulas. Further investigation should include variable HMO mixtures and doses to optimize infant nutrition at this critical stage.

Spectral study of the Galactic ridge X-ray emission with Suzaku: Comparison of the spectral shape with point sources

Abstract The Galactic ridge X-ray emission (GRXE) is unresolved X-ray emission located on the Galactic plane, and whether the GRXE comes from truly diffuse plasma or unresolved point sources is still debatable. We present results of spectral analysis of the GRXE with Suzaku. In order to examine the point source origin, we fitted the GRXE spectra in the 1.2–10 keV energy band with a point source model, which is a mixture of active binary stars (ABs) and non-magnetic cataclysmic variables (non-mCVs), and found that the model cannot represent the GRXE spectral shape as long as the standard metal abundances of these species are assumed. In particular, the standard abundance model cannot account for the observed intensities of Si, S, and Ar lines as well as the previously reported Fe line. Assuming spatial densities in the solar neighborhood, integration of the ABs and non-mCVs accounts for only 30% of the observed GRXE flux. Other species of the point sources or diffuse emission with stronger Si, S, Ar, and Fe emission lines shall explain the rest.

Association between psychological distress trajectories from adolescence to midlife and mental health during the pandemic: evidence from two British birth cohorts.

This paper examined whether distinct life-course trajectories of psychological distress from adolescence to midlife were associated with poorer mental health outcomes during the pandemic. We present a secondary analysis of two nationally representative British birth cohorts, the 1958 National Child Development Study (NCDS) and 1970 British Cohort Study (BCS70). We used latent variable mixture models to identify pre-pandemic longitudinal trajectories of psychological distress and a modified Poisson model with robust standard errors to estimate associations with psychological distress, life satisfaction and loneliness at different points during the pandemic. Our analysis identified five distinct pre-pandemic trajectories of psychological distress in both cohorts. All trajectories with prior symptoms of psychological distress irrespective of age of onset, severity and chronicity were associated with a greater relative risk of poorer mental health outcomes during the pandemic and the probability of poorer mental health associated with psychological distress trajectories remained fairly constant. The relationship was not fully attenuated when most recent pre-pandemic psychological distress and other midlife factors were controlled for. Whilst life-course trajectories with any prior symptoms of psychological distress put individuals at greater risk of poor mental health outcomes during the pandemic, those with chronic and more recent occurrences were at highest risk. In addition, prior poor mental health during the adult life-course may mean individuals are less resilient to shocks, such as pandemics. Our findings show the importance of considering heterogeneous mental health trajectories across the life-course in the general population in addition to population average trends.

Mixed cumulative probit: a multivariate generalization of transition analysis that accommodates variation in the shape, spread and structure of data.

Biological data are frequently nonlinear, heteroscedastic and conditionally dependent, and often researchers deal with missing data. To account for characteristics common in biological data in one algorithm, we developed the mixed cumulative probit (MCP), a novel latent trait model that is a formal generalization of the cumulative probit model usually used in transition analysis. Specifically, the MCP accommodates heteroscedasticity, mixtures of ordinal and continuous variables, missing values, conditional dependence and alternative specifications of the mean response and noise response. Cross-validation selects the best model parameters (mean response and the noise response for simple models, as well as conditional dependence for multivariate models), and the Kullback-Leibler divergence evaluates information gain during posterior inference to quantify mis-specified models (conditionally dependent versus conditionally independent). Two continuous and four ordinal skeletal and dental variables collected from 1296 individuals (aged birth to 22 years) from the Subadult Virtual Anthropology Database are used to introduce and demonstrate the algorithm. In addition to describing the features of the MCP, we provide material to help fit novel datasets using the MCP. The flexible, general formulation with model selection provides a process to robustly identify the modelling assumptions that are best suited for the data at hand.

The Cultural Factors in Moderate to Severe Depression and Relevant Interventions

Depression is resulted from a mixture of hereditary and environmental variables. This article mainly considered biological, genetic, and psychological influences on depression. For environmental aspects, this paper aims to identify the impact of different cultures on depression. The most relevant previous studies were reviewed. The findings suggest that culture does play a role in the development of depression. This review mainly examined studies that compared the effects of individualistic and collectivistic cultures on depression. Traditional filial piety culture and thin culture showed different effects on depression. In addition to the traditional gender roles of certain cultures, caste and other cultural differences can also have an impact on the development of depression. Similarly, prenatal depression is more common in immigrants and poor countries than in non-immigrants and industrialized countries. Resilience and social support are two protective factors for mental health, and these two factors have different degrees of influence depending on the culture. There is still limited amount of research investigated the effects of different cultures on depression. More research on the characteristics of different cultures and their association with depression is needed in the future. This review can provide some guidance for furture research and practice. Prevention and intervention programs for children and families should incorporate cultural factors.

Latent class analysis of multigroup heterogeneity in propensity for academic dishonesty

ABSTRACT Latent class analysis (LCA) is a cross-sectional latent variable mixture modeling (LVMM) approach. Like all LVMM approaches, LCA aims to find heterogeneity within the population by identifying homogenous subgroups of individuals, with each subgroup (called latent class) possessing a unique set of characteristics that differentiate it from other subgroups. LCA can be carried out with categorical latent and indicator variables. But, LCA is unable to examine the association between respective items and the latent variable among categories of individuals. Multiple-group LCA, in particular, is a useful extension of LCA which enables the testing of homogeneity of the class patterns between groups of the individual through a series of constraints. In this paper, we have performed a multi-group latent class analysis for measuring self reported academic dishonesty among the students of University of Jammu. From the analysis, three general behaviors of academic cheaters are identified as rare, frequent, and instant cheaters. Further, from the multi-group LCA, it is envisaged that female students of University of Jammu are more instantaneous cheaters than male students. Students who are self-reported cheaters from sciences and humanities of the University of Jammu are persistent in cheating whereas from professional courses they are more occasional.

A Systematic Literature Review of Latent Variable Mixture Modeling in Communication Scholarship

ABSTRACT Recently, latent variable mixture modeling has gained traction in many disciplines, given its unique ability to discover unknown groups within a broader population. Indeed, this method assumes that a finite number of mixtures (i.e. unknown groups) exist within the population and can be discovered by evaluating participants’ response patterns to a set of manifest indicators. Despite the intuitive approach, recommendations have been proposed to overcome some methodological concerns associated with latent variable mixture modeling. The primary purpose of this study was to understand the characteristics of latent variable mixture modeling in communication research and to evaluate the extent to which the existing research meets these recommendations. Ninety-five manuscripts published between 2010 and 2022 in 18 communication journals were identified and systematically analyzed. The review found that (1) the use of latent variable mixture modeling has increased; (2) latent class analysis and latent profile analysis are the most common models; and (3) most manuscripts did not meet the proscribed standards for random start values, auxiliary variable procedures, indicator requirements, and missing data procedures. These findings are discussed more in comparison with the proscribed standards. In addition, conceptual and applicable recommendations are provided to improve communication scholarship.

Heavy Mineral Distribution and Clay Mineralogy of Injana Formation at Zawita and Daigala Northern Iraq

This study deals with the minerology of Injana Formation (Late Miocene- Pliocene) at Zawita and Daigala sections, north of Iraq. A total of 13 samples are collected from Injana Formation. The heavy minerals assemblages include opaque minerals, orthopyroxenes, clinopyroxenes, zircon, rutile, epidotes, garnet, amphiboles, tourmaline, chlorite, biotite, kyanite, muscovite and staurolite. The source rocks of these assemblages of heavy minerals are mafic igneous and metamorphic rocks principally as well as acidic igneous and old sedimentary rocks. The ZTR indices indicate the Injana sandstone is mineralogically immature .The tectonic origins of Injana Formation is characterized as lithic recycled of recycled orogeny .The mudstone consists of mixture of clay and silt percentage variable. The major clay minerals are chlorite, kaolinite, illite and smectite. The non-clay minerals are calcite, quartz and subordinate feldspars. The mineralogy of the clay fraction of Injana mudstone leads to be climate arid to semi-arid

Hybrid time‐dependent reliability analysis under a mixture of random and interval uncertainties

AbstractA new time‐dependent reliability analysis model with a mixture of random variables and interval variables is proposed in this paper. First, samples of random variables are generated according to their probability density functions. Then, the samples are substituted into the performance function to obtain the interval processes corresponding to these samples. The reliability index of each interval process is computed to finally obtain the upper and lower bounds of failure probability. The adaptive Kriging surrogate model based on the global addition strategy is used in the calculation process to increase the computational efficiency. The accuracy of the computational strategy is demonstrated by a mathematical example and three engineering practical cases. The proposed new hybrid time‐dependent reliability model is compared to the conventional hybrid reliability model. The comparison results show that the proposed model is more convenient to implement than the conventional reliability model. It can accurately evaluate the reliability of the structure and can be applied to real‐world engineering practice thereby providing assistance and guidance for hybrid time‐dependent reliability analysis of structures.

Climate-driven mid- to late Holocene hydrologic evolution of arid wetlands documented by strontium, uranium, and oxygen isotopes from Lower Pahranagat Lake, southern Nevada, USA

AbstractLacustrine carbonates in a 12.4-m-long core from Lower Pahranagat Lake (LPAH), southern Nevada, indicate that radiogenic isotopes of Sr and U (87Sr/86Sr and 234U/238U) preserve evidence of past variations in water sources and evolving hydrologic conditions. Sr and U isotope compositions in LPAH carbonates fall within the range defined by the three primary groundwater sources in Pahranagat Valley and reflect variable mixtures of those sources since the mid-Holocene. Compositions in the oldest sample (5.78 ka) closely match modern compositions of modern discharge from nearby springs, indicating that LPAH water was derived almost exclusively from the local volcanic aquifer. By ca. 5.3–5.2 ka, LPAH water compositions shifted sharply towards isotopic compositions observed in groundwater from the regional carbonate aquifer, indicating a marked increase in surface flow from high-volume springs discharging from the carbonate aquifer to the north. Sediments deposited between 3.08–1.06 ka indicate reduced contributions from the regional aquifer. A comparison of uranium- and oxygen-isotope values in LPAH carbonates suggests that wetter climate conditions favor increased supply from deeper, regional carbonate aquifers compared to drier conditions when contributions from shallower, local volcanic aquifers were more important.