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Evaluation of thermal water in patients with functional dyspepsia and irritable bowel syndrome accompanying constipation 认领 引用 被引量：15
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作者 Giovanni Gasbarrini Marcello Candelli +3 位作者 RiccardoGiuseppe Graziosetto Sergio Coccheri Ferdinando Di Iorio Giuseppe Nappi 《World Journal of Gastroenterology》 SCIE CAS 2006年第16期2556-2562,共7页
AIM： To evaluate the efficacy of water supplementation treatment in patients with functional dyspepsia or irritable bowe syndrome （IBS） accompanying predominant constipation. METHODS： A total of 3872 patients with... AIM： To evaluate the efficacy of water supplementation treatment in patients with functional dyspepsia or irritable bowe syndrome （IBS） accompanying predominant constipation. METHODS： A total of 3872 patients with functional dyspepsia and 3609 patients with irritable bowel syndrome were enrolled in the study by 18 Italina thermal centres. Patients underwent a first cycle of thermal therapy for 21 d. A year later patients were re-evaluated at the same centre and received another cycle of thermal therapy. A questionnare to collect personal data on social and occupational status, family and pathological case history, life style, clinical records, utilisation of welfare and health structure and devices was administered to each patient at basal time and one year after each thermal treatment. Sixty patients with functional dyspepsia and 20 with IBS and 80 healthy controls received an evaluation of gastric output and oro-cecal transit time by breath test analysis. Breath test was performed at basal time and after water supplementaton therapies. Gastrointestinal symptoms were evaluated at the same time points. Breath samples were analyzed with a mass spectometer and a gascromatograph. Results were expressed as T1/2 and T-lag for octanoic add breath test and as oro-cecal transit time for lactulose breath test. RESULTS： A significant reduction of prevalence of symptoms was observed at the end of the first and second cycles of thermal therapy in dyspeptic and IBS patients, The analysis of variance showed a real and persistant improvement of symptoms in all patients. After water supplementation for 3 wk a reduction of gastric output was observed in 49 （87.5%） of 56 dyspepUc patients. Both T1/2 and T-lag were significantly reduced after the therapy compared to basal values [91 ± 12 （T1/2） and 53± 11 （T-lag）, Tables 1 and 2] with results of octanoic acid breath test similar to healthy subjects. After water supplementation for 3 wk oro-cecal transit time was shorter than that at the beginning of the study. CONCLUSION： Mineral water supplementation treatment for functional dyspepsia or conspipation accompanying IBS can improve gastric add output and intestinal transit time. 展开更多
关键词 Mineral water Constipation Dispepsia Thermal therapy
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Incorporation of Parameter Uncertainty into Spatial Interpolation Using Bayesian Trans-Gaussian Kriging 认领 引用 被引量：6
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作者 Joon Jin SONG Soohyun KWON Gyu Won LEE 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2015年第3期413-423,共11页
Quantitative precipitation estimation （QPE） plays an important role in meteorological and hydrological applications.Ground-based telemetered rain gauges are widely used to collect precipitation measurements.Spatial ... Quantitative precipitation estimation （QPE） plays an important role in meteorological and hydrological applications.Ground-based telemetered rain gauges are widely used to collect precipitation measurements.Spatial interpolation methods are commonly employed to estimate precipitation fields covering non-observed locations.Kriging is a simple and popular geostatistical interpolation method,but it has two known problems：uncertainty underestimation and violation of assumptions.This paper tackles these problems and seeks an optimal spatial interpolation for QPE in order to enhance spatial interpolation through appropriately assessing prediction uncertainty and fulfilling the required assumptions.To this end,several methods are tested：transformation,detrending,multiple spatial correlation functions,and Bayesian kriging.In particular,we focus on a short-term and time-specific rather than a long-term and event-specific analysis.This paper analyzes a stratiform rain event with an embedded convection linked to the passing monsoon front on the 23 August 2012.Data from a total of 100 automatic weather stations are used,and the rainfall intensities are calculated from the difference of 15 minute accumulated rainfall observed every 1 minute.The one-hour average rainfall intensity is then calculated to minimize the measurement random error.Cross-validation is carried out for evaluating the interpolation methods at regional and local levels.As a result,transformation is found to play an important role in improving spatial interpolation and uncertainty assessment,and Bayesian methods generally outperform traditional ones in terms of the criteria. 展开更多
关键词 precipitation kriging transformation Bayesian kriging detrend Korea
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Multimodality Prediction of Chaotic Time Series with Sparse Hard-Cut EM Learning of the Gaussian Process Mixture Model 认领 引用 被引量：2
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作者 周亚同 樊煜 +1 位作者 陈子一 孙建成 《Chinese Physics Letters》 SCIE EI CAS CSCD 2017年第5期22-26,共5页
The contribution of this work is twofold： （1） a multimodality prediction method of chaotic time series with the Gaussian process mixture （GPM） model is proposed, which employs a divide and conquer strategy. It au... The contribution of this work is twofold： （1） a multimodality prediction method of chaotic time series with the Gaussian process mixture （GPM） model is proposed, which employs a divide and conquer strategy. It automatically divides the chaotic time series into multiple modalities with different extrinsic patterns and intrinsic characteristics, and thus can more precisely fit the chaotic time series. （2） An effective sparse hard-cut expec- tation maximization （SHC-EM） learning algorithm for the GPM model is proposed to improve the prediction performance. SHO-EM replaces a large learning sample set with fewer pseudo inputs, accelerating model learning based on these pseudo inputs. Experiments on Lorenz and Chua time series demonstrate that the proposed method yields not only accurate multimodality prediction, but also the prediction confidence interval SHC-EM outperforms the traditional variational 1earning in terms of both prediction accuracy and speed. In addition, SHC-EM is more robust and insusceptible to noise than variational learning. 展开更多
关键词 GPM Multimodality Prediction of Chaotic Time Series with Sparse Hard-Cut EM Learning of the Gaussian Process Mixture Model EM SHC
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Robust estimation of time-dependent precision matrix with application to the cryptocurrency market 认领 引用 被引量：1
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作者 Paola Stolfi Mauro Bernardi Davide Vergni 《Financial Innovation》 2022年第1期1313-1337,共25页
Most financial signals show time dependency that,combined with noisy and extreme events,poses serious problems in the parameter estimations of statistical models.Moreover,when addressing asset pricing,portfolio select... Most financial signals show time dependency that,combined with noisy and extreme events,poses serious problems in the parameter estimations of statistical models.Moreover,when addressing asset pricing,portfolio selection,and investment strategies,accurate estimates of the relationship among assets are as necessary as are delicate in a time-dependent context.In this regard,fundamental tools that increasingly attract research interests are precision matrix and graphical models,which are able to obtain insights into the joint evolution of financial quantities.In this paper,we present a robust divergence estimator for a time-varying precision matrix that can manage both the extreme events and time-dependency that affect financial time series.Furthermore,we provide an algorithm to handle parameter estimations that uses the“maximization–minimization”approach.We apply the methodology to synthetic data to test its performances.Then,we consider the cryptocurrency market as a real data application,given its remarkable suitability for the proposed method because of its volatile and unregulated nature. 展开更多
关键词 Time-varying models Robust methods Kernel estimation Precision matrix Divergence
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A Comparison of Two Linear Discriminant Analysis Methods That Use Block Monotone Missing Training Data 认领 引用
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作者 Phil D. Young Dean M. Young Songthip T. Ounpraseuth 《Open Journal of Statistics》 2016年第1期172-185,共14页
We revisit a comparison of two discriminant analysis procedures, namely the linear combination classifier of Chung and Han (2000) and the maximum likelihood estimation substitution classifier for the problem of classi... We revisit a comparison of two discriminant analysis procedures, namely the linear combination classifier of Chung and Han (2000) and the maximum likelihood estimation substitution classifier for the problem of classifying unlabeled multivariate normal observations with equal covariance matrices into one of two classes. Both classes have matching block monotone missing training data. Here, we demonstrate that for intra-class covariance structures with at least small correlation among the variables with missing data and the variables without block missing data, the maximum likelihood estimation substitution classifier outperforms the Chung and Han (2000) classifier regardless of the percent of missing observations. Specifically, we examine the differences in the estimated expected error rates for these classifiers using a Monte Carlo simulation, and we compare the two classifiers using two real data sets with monotone missing data via parametric bootstrap simulations. Our results contradict the conclusions of Chung and Han (2000) that their linear combination classifier is superior to the MLE classifier for block monotone missing multivariate normal data. 展开更多
关键词 Linear Discriminant Analysis Monte Carlo Simulation Maximum Likelihood Estimator Expected Error Rate Conditional Error Rate
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Spatial Modeling and Mapping of Tuberculosis Using Bayesian Hierarchical Approaches 认领 引用 被引量：1
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作者 Abdul-Karim Iddrisu Yaw Ampem Amoako 《Open Journal of Statistics》 2016年第3期482-513,共32页
Global spread of infectious disease threatens the well-being of human, domestic, and wildlife health. A proper understanding of global distribution of these diseases is an important part of disease management and poli... Global spread of infectious disease threatens the well-being of human, domestic, and wildlife health. A proper understanding of global distribution of these diseases is an important part of disease management and policy making. However, data are subject to complexities by heterogeneity across host classes. The use of frequentist methods in biostatistics and epidemiology is common and is therefore extensively utilized in answering varied research questions. In this paper, we applied the hierarchical Bayesian approach to study the spatial distribution of tuberculosis in Kenya. The focus was to identify best fitting model for modeling TB relative risk in Kenya. The Markov Chain Monte Carlo (MCMC) method via WinBUGS and R packages was used for simulations. The Deviance Information Criterion (DIC) proposed by [1] was used for models comparison and selection. Among the models considered, unstructured heterogeneity model perfumes better in terms of modeling and mapping TB RR in Kenya. Variation in TB risk is observed among Kenya counties and clustering among counties with high TB Relative Risk (RR). HIV prevalence is identified as the dominant determinant of TB. We find clustering and heterogeneity of risk among high rate counties. Although the approaches are less than ideal, we hope that our formulations provide a useful stepping stone in the development of spatial methodology for the statistical analysis of risk from TB in Kenya. 展开更多
关键词 Bayesian Hierarchical Heterogeneity Deviance Information Criterion (DIC) Markov Chain Monte Carlo (MCMC) Host Classes Relative Risk
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Management factors affecting densities of common grassland birds of high elevation grasslands of eastern South Africa:Ingula as a case study 认领 引用
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作者 David H.Maphisa Hanneline Smit-Robinson +1 位作者 Les G.Underhill Res Altwegg 《Chinese Birds》 2017年第1期37-49,共13页
Background: World?wide grassland birds are in decline due to habitat loss and degradation resulting from inten?sive agricultural practices. Understanding how key grassland habitat attributes determine grassland bird d... Background: World?wide grassland birds are in decline due to habitat loss and degradation resulting from inten?sive agricultural practices. Understanding how key grassland habitat attributes determine grassland bird densities is required to make appropriate conservation decisions. We examine drivers of bird densities in a South African grass?land area that has been managed for biodiversity conservation with reduced grazing pressure.Methods: We estimated the density of the eight most common grassland bird species encountered in our area to evaluate the effects of recent grassland management changes on the avifauna. We collected data on birds and habitat from the austral summers of 2006/2007, 2007/2008 and 2010/2011. We used hierarchical distance sampling methods to estimate density of birds relative to two main habitat variables, i.e., grass cover and height. In addition, we used regression splines within these distance sampling models as a more flexible description of suitable ranges of grass height and cover for each species.Results: For most species, density is related to grass height and cover as expected. The African Quailfinch(Ortygospiza atricollis) and Common Quail(Coturnix coturnix) preferred relatively short and open grass. The Yellow?breasted Pipit(Anthus chloris), African Pipit(Anthus cinnamomeus) and Red?capped Lark(Calandrella cinerea) preferred short and relatively dense grass, while the Wing?snapping Cisticola(Cisticola ayresii) preferred grass of intermediate height and cover. The Cape Longclaw(Macronyx capensis) and Zitting Cisticola(Cisticola juncidis) preferred tall and dense grass. Our results agree with previous studies that grass height combined with grass cover are the most important habitat features that managers should manipulate in order to increase the density of target species. The regression splines show that the effect of these two habitat variables on density is well described by linear relationships for most species.Conclusions: This study supports previous studies suggesting that grazing and fire are important tools for manage?ment to use in order to create a mosaic of grass height and cover that would support high densities of desired spe?cies. We suggest that conservation managers of these grasslands combine fire and grazing as management tools to create suitable habitats for grassland birds in general. 展开更多
关键词 Density and detection Grassland birds Grass height and cover Hierarchical distance sampling models
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Distributions of Risk Functions for the Pareto Model 认领 引用
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作者 Fulvio De Santis Stefania Gubbiotti Marco Perone Pacifico 《Open Journal of Statistics》 2024年第6期721-736,共16页
In statistical decision theory, the risk function quantifies the average performance of a decision over the sample space. The risk function, which depends on the parameter of the model, is often summarized by the Baye... In statistical decision theory, the risk function quantifies the average performance of a decision over the sample space. The risk function, which depends on the parameter of the model, is often summarized by the Bayes risk, that is its expected value with respect to a design prior distribution assigned to the parameter. However, since expectation may not be an adequate synthesis of the random risk, we propose to examine the whole distribution of the risk function. Specifically, we consider point and interval estimation for the two parameters of the Pareto model. Using conjugate priors, we derive closed-form expressions for both the expected value and the density functions of the risk of each parameter under suitable losses. Finally, an application to wealth distribution is illustrated. 展开更多
关键词 Bayes Risk Point Estimation Interval Estimation Prior Distributions Statistical Decision Theory
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Levels and Typologies of Participation in Sports in Europe: Methodological and Operational Challenges 认领 引用
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作者 Antonio Mussino 《Journal of Sports Science》 2014年第1期32-46,共15页
Under the aegis of Lisbon Treaty, individual member states of EU （European Union） are ＂encouraged to implement evidence-based policies in order to improve their provision of sporting facilities and opportunities＂.... Under the aegis of Lisbon Treaty, individual member states of EU （European Union） are ＂encouraged to implement evidence-based policies in order to improve their provision of sporting facilities and opportunities＂. In this framework, a survey （Eurobarometer 72.3） was commissioned by the European Commission, which helps us to understand the behaviour of European societies in the field of participation in sport and in physical activities. In the paper, we measure the levels of involvement of EU citizens in active life styles. We do not analyse issued results, but use the individual record file, reprocessing data in different ways. We try to reconstruct the COMPASS （Co-Ordinated Monitoring of Participation in Sports） general model with the available information. The patterns of participation are studied in relation to the socio-demographic variables. The main result is the individualisation of a ＂six groups＂ （six typologies） solution for a cluster analysis of the participants to the survey. The clusters may be so labelled： occasional sport engagement; active participation; intensive open air activities; fitness world; traditional sport world; non active people. We find strong differences in the levels of participation among EU countries, whose determinants are both motivational and socio-demographic, and are linked to the national sport policies. 展开更多
关键词 Sport participation surveys clusters ranking sport policies.
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Comparative Analysis of Machine Learning Models for Customer Churn Prediction in the U.S. Banking and Financial Services: Economic Impact and Industry-Specific Insights 认领 引用
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作者 Omoshola S. Owolabi Prince C. Uche +4 位作者 Nathaniel T. Adeniken Oghenekome Efijemue Samuel Attakorah Oluwabukola G. Emi-Johnson Emmanuel Hinneh 《Journal of Data Analysis and Information Processing》 2024年第3期388-418,共31页
Customer churn poses a significant challenge for the banking and finance industry in the United States, directly affecting profitability and market share. This study conducts a comprehensive comparative analysis of ma... Customer churn poses a significant challenge for the banking and finance industry in the United States, directly affecting profitability and market share. This study conducts a comprehensive comparative analysis of machine learning models for customer churn prediction, focusing on the U.S. context. The research evaluates the performance of logistic regression, random forest, and neural networks using industry-specific datasets, considering the economic impact and practical implications of the findings. The exploratory data analysis reveals unique patterns and trends in the U.S. banking and finance industry, such as the age distribution of customers and the prevalence of dormant accounts. The study incorporates macroeconomic factors to capture the potential influence of external conditions on customer churn behavior. The findings highlight the importance of leveraging advanced machine learning techniques and comprehensive customer data to develop effective churn prevention strategies in the U.S. context. By accurately predicting customer churn, financial institutions can proactively identify at-risk customers, implement targeted retention strategies, and optimize resource allocation. The study discusses the limitations and potential future improvements, serving as a roadmap for researchers and practitioners to further advance the field of customer churn prediction in the evolving landscape of the U.S. banking and finance industry. 展开更多
关键词 Churn Prediction Machine Learning Economic Impact Industry-Specific Insights Logistic Regression Random Forest Neural Networks
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Reduced fibre-fermenting capacity of gut microbes in multiple sclerosis may result in prebiotic dietary fibre β-fructan promoting inflammation and CNS damage 认领 引用
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作者 Stephanie L Tollenaar Reihane Khorasaniha +28 位作者 Juan Jovel Ismaila Ba Athalia Voisin Richard Miller Hana Olof Ramsha Mahmood Ruth Ann Marrie Erin Strachan Luisa P Soares Christopher Cheng Jonathan Janveaux Deenaz Zaidi Charles N Bernstein Christine Bonner Amit Bar-Or Emmanuelle Waubant E Ann Yeh Morag Graham Douglas L Arnold Julia O’Mahony Brenda L Banwell Feng Zhu Ali I Mirza Soheila Karimi-Abdolrezaee Sue Tsai Helen Tremlett Kevin McGregor Benjamin P Willing Heather Armstrong 《eGastroenterology》 2026年第1期90-103,共14页
Background Some people with multiple sclerosis display changes in their gut microbiota with separate evidence suggesting that symptoms may worsen following a high-fibre diet.We hypothesised that in people with multipl... Background Some people with multiple sclerosis display changes in their gut microbiota with separate evidence suggesting that symptoms may worsen following a high-fibre diet.We hypothesised that in people with multiple sclerosis whose gut microbiota are less able to efficiently ferment dietary fibres,unfermented β-fructans induce inflammation.Methods Diet data(n=48 individuals with multiple sclerosis,n=78 unaffected controls)and stool microbiome data(n=31 individuals with multiple sclerosis,n=61 unaffected controls)were previously collected from participants.Daily fibre subtype intakes were calculated and compared with faecal shotgun metagenomic sequencing in paediatric onset multiple sclerosis and unaffected persons.Response to unfermented β-fructans was examined in a germ-free experimental autoimmune encephalomyelitis(EAE)mouse model(unable to ferment fibres).Mice were fed β-fructans or control fibre diet beginning at symptom onset(day 14).EAE scores and weights were recorded daily.Intestinal and central nervous system tissues were collected at two endpoints to examine inflammatory responses and demyelinating lesions.Results Individuals with paediatric onset multiple sclerosis consumed less β-fructans(2.4 g/day±0.3 SD;p<0.05)than unaffected participants(3.6 g/day±0.4),which coincided with differences in the gut microbiota including lower fibre fermenting enzymes.Mice exposed to unfermented β-fructans sustained worsened EAE symptoms(day 20-28;p<0.05),immune activation in the gut and immune activation plus demyelinating lesions in the spinal cord compared with mice on control diet.Conclusions The gut microbiota of individuals with paediatric-onset multiple sclerosis showed reduced fibre fermenting properties,and our animal findings suggest that unfermented β-fructans can worsen demyelination and promote gut–brain axis immune activation.Lower β-fructan consumption was observed among participants with paediatric-onset multiple sclerosis.Future longitudinal studies are warranted to confirm the findings uncovered in this manuscript. 展开更多
关键词 ferment dietary fibresunfermented multiple sclerosis multiple sclerosisn Inflammation Fructans gut microbiota stool microbiome data n
Multivariate GARCH models with spherical parameterizations:an oil price application 认领 引用
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作者 Luca Vincenzo Ballestra Riccardo De Blasis Graziella Pacelli 《Financial Innovation》 2025年第1期1158-1177,共20页
In popular Baba-Engle-Kraft-Kroner(BEKK)and dynamic conditional correlation(DCC)multivariate generalized autoregressive conditional heteroskedasticity models,the large number of parameters and the requirement of posit... In popular Baba-Engle-Kraft-Kroner(BEKK)and dynamic conditional correlation(DCC)multivariate generalized autoregressive conditional heteroskedasticity models,the large number of parameters and the requirement of positive definiteness of the covariance and correlation matrices pose some difficulties during the estimation process.To avoid these issues,we propose two modifications to the BEKK and DCC models that employ two spherical parameterizations applied to the Cholesky decompositions of the covariance and correlation matrices.In their full specifications,the introduced Cholesky-BEKK and Cholesky-DCC models allow for a reduction in the number of parameters compared with their traditional counterparts.Moreover,the application of spherical transformation does not require the imposition of inequality constraints on the parameters during the estimation.An application to two crude oils,WTI and Brent,and the main exchange rate prices demonstrates that the Cholesky-BEKK and Cholesky-DCC models can capture the dynamics of covariances and correlations.In addition,the Kupiec test on different portfolio compositions confirms the satisfactory performance of the proposed models. 展开更多
关键词 BEKK Cholesky-GARCH Crude oils DCC Exchange rates Spherical parameterization
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利用3种不同化学计量学方法分析枸杞子抗氧化部位的谱效关系 认领 引用 被引量：20
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作者 王振宇 杨斯月 +3 位作者 吕维 丁建宝 马建龙 杨晋 《中国中药杂志》 CAS CSCD 北大核心 2021年第13期3377-3387,共11页
采用液相色谱-质谱联用技术分析化学成分并与体外抗氧化活性相联系,建立谱效关系研究,明确枸杞子抗氧化活性成分。该实验采用不同溶剂分次提取,结合大孔吸附树脂和反相色谱纯化技术,将枸杞子提取物分为80个不同的供试品;通过体外实验结... 采用液相色谱-质谱联用技术分析化学成分并与体外抗氧化活性相联系,建立谱效关系研究,明确枸杞子抗氧化活性成分。该实验采用不同溶剂分次提取,结合大孔吸附树脂和反相色谱纯化技术,将枸杞子提取物分为80个不同的供试品;通过体外实验结果提示,枸杞子中的体外抗氧化活性成分被富集到11个供试品中,这些样品的清除DPPH自由基和FRAP能力都显著强于处理前的流分(P<0.05);采集抗氧化样品的UPLC-MS/MS图谱,选用Pearson相关分析、正交偏最小二乘法和弹性网络回归,建立枸杞子抗氧化活性谱效关系。结合3种不同的数据分析技术,明确了6个色谱峰对枸杞子体外抗氧化活性贡献较大,利用质谱数据,将其鉴定为芦丁(P6)、槲皮素(P35)、东莨菪内酯(P14)、N-cis-feruloyl-4-O-β-D-glucopyranosyl-tyramine或N-(4-O-β-D-glucopyranosyl-trans-feruloyl)-tyramine(P8)、阿魏酸(P13)和1,3,5-dihydroxy-2-isoprenyl-3-xanthone(P23)。与清除自由基相关的活性成分为黄酮类化合物芦丁和槲皮素,还原Fe3+的物质基础是苯丙素类成分阿魏酸、东莨菪内酯以及xanthone和酚胺,说明枸杞子的抗氧化活性是不同产物通过不同途径协同作用的结果,同时也提示,谱效关系应该谨慎选择数据分析模型,保证结果的可靠性。 展开更多
关键词 枸杞子 抗氧化 谱效关系 皮尔逊相关 正交偏最小二乘法 弹性网络回归
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Linking forest diversity and tree health: preliminary insights from a large-scale survey in Italy 认领 引用 被引量：2
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作者 Filippo Bussotti Matteo Feducci +3 位作者 Giovanni Iacopetti Filomena Maggino Martina Pollastrini Federico Selvi 《Forest Ecosystems》 SCIE CSCD 2018年第2期151-161,共11页
Forest health is currently assessed in Europe （ICP Forests monitoring program）. Crown defoliation and dieback, tree mortality, and pathogenic damage are the main aspects considered in tree health assessment. The wor... Forest health is currently assessed in Europe （ICP Forests monitoring program）. Crown defoliation and dieback, tree mortality, and pathogenic damage are the main aspects considered in tree health assessment. The worsening of environmental conditions （i.e., increase of temperature and drought events） may cause large-spatial scale tree mortality and forest decline. However, the role of stand features, including tree species assemblage and diversity as factors that modify environmental impacts, is poorly considered. The present contribution reanalyses the historical dataset of crown conditions in Italian forests from ] 997 to 2014 to identify ecological and structural factors that influence tree crown defoliation, highlighting in a special manner the role of tree diversity. The effects of tree diversity were explored using the entire data set through multivariate cluster analyses and on individual trees, analysing the influence of the neighbouring tree diversity and identity at the local （neighbour） level. Preliminary results suggest that each tree species shows a specific behaviour in relation to crown defoliation, and the distribution of crown defoliation across Italian forests reflects the distribution of the main forest types and their ecological equilibrium with the environment. The potentiality and the problems connected to the possible extension of this analysis at a more general level （European and North American） were discussed. 展开更多
关键词 Cluster analysis Crown defoliation Forest structure ICP Forests Neighbouring trees Tree diversity Tree identity
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Psychiatric comorbidities in epilepsy:population co-occurrence,genetic correlations and causal effects 认领 引用 被引量：2
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作者 Viktor H Ahlqvist Christina Dardani +14 位作者 Paul Madley-Dowd Harriet Forbes Jessica Rast Caichen Zhong Renee M Gardner Christina Dalman Kristen Lyal cRAIG Newschaffer Torbjorn Tomson Michael Lundberg Daniel Berglind Neil M Davies Brian K Lee Cecilia Magnusson Dheeraj Rai 《General Psychiatry》 CSCD 2024年第1期103-111,共9页
Background Psychiatric comorbidities are common in patients with epilepsy.Reasons for the co-occurrence of psychiatric conditions and epilepsy remain poorly understood.Aim We aimed to triangulate the relationship betw... Background Psychiatric comorbidities are common in patients with epilepsy.Reasons for the co-occurrence of psychiatric conditions and epilepsy remain poorly understood.Aim We aimed to triangulate the relationship between epilepsy and psychiatric conditions to determine the extent and possible origins of these conditions.Methods Using nationwide Swedish health registries,we quantified the lifetime prevalence of psychiatric disorders in patients with epilepsy.We then used summarydata from genome-wide association studies to investigate whether the identified observational associations could be attributed to a shared underlying genetic aetiology using cross-trait linkage disequilibrium score regression.Finally,we assessed the potential bidirectional relationships using two-sample Mendelian randomisation.Results In a cohort of 7628495 individuals,we found that almost half of the 94435 individuals diagnosed with epilepsy were also diagnosed with a psychiatric condition in their lifetime(adjusted lifetime prevalence,44.09%;95%confidence interval(Cl)43.78%to 44.39%).We found evidence for a genetic correlation between epilepsy and some neurodevelopmental and psychiatric conditions.For example,we observed a genetic correlation between epilepsy and attention-deficit/hyperactivity disorder(r,=0.18,95%Cl 0.09 to 0.27,p<0.001)—a correlation that was more pronounced in focal epilepsy(r=0.23,95%CI 0.09 to 0.36,p<0.001).Findings from Mendelian randomisation using common genetic variants did not support bidirectional effects between epilepsy and neurodevelopmental or psychiatric conditions.Conclusions Psychiatric comorbidities are common in patients with epilepsy.Genetic correlations may partially explain some comorbidities;however,there is little evidence of a bidirectional relationship between the genetic liability of epilepsy and psychiatric conditions.These findings highlight the need to understand the role of environmental factors or rare genetic variations in the origins of psychiatric comorbidities in epilepsy. 展开更多
关键词 epilepsy Psychiat lifetime
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贝叶斯网络模型在体检结果分析中的应用 认领 引用 被引量：3
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作者 王思聪 石超珺 +6 位作者 滕斌 乔鲁燕 李赞华 王镜涵 曾庆嘉 秦亚星 冯珊 《中国卫生统计》 CSCD 北大核心 2020年第6期832-834,839,共3页
目的探讨贝叶斯网络在医务人员健康状况分析中的应用,为医务人员健康管理提供方向和思路。方法通过半朴素贝叶斯(TAN)构建年龄、性别、部门(临床/非临床)等基本信息之间的连接,以此为基础建立贝叶斯网络表示各体检指标间的关联关系。结... 目的探讨贝叶斯网络在医务人员健康状况分析中的应用,为医务人员健康管理提供方向和思路。方法通过半朴素贝叶斯(TAN)构建年龄、性别、部门(临床/非临床)等基本信息之间的连接,以此为基础建立贝叶斯网络表示各体检指标间的关联关系。结果在2014-2017年某三甲医院医务人员体检数据上,贝叶斯网络以年龄、性别、肝脏为3个中心结点,建立起与其他体检指标的关联。以中心结点肝脏为条件的分组异常检出率统计及贝叶斯网络推断结果同时显示:该院医务人员肝脏与甲状腺、胆囊、肾脏、体重指标之间的关联性差异有统计学意义。结论贝叶斯网络对于建立医务人员体检管理体系具有可参考价值。 展开更多
关键词 贝叶斯网络 半朴素贝叶斯 关联性分析 医务人员 体检结果
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A General Hermitian Nonnegative-Definite Solution to the Matrix Equation AXB= C 认领 引用 被引量：2
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作者 Phil D. Young Dean M. Young Marsha M. Young 《Advances in Linear Algebra & Matrix Theory》 2017年第1期7-17,共11页
We derive necessary and sufficient conditions for the existence of a Hermitian nonnegative-definite solution to the matrix equation AXB = C. Moreover, we derive a representation of a general Hermitian nonnegative-defi... We derive necessary and sufficient conditions for the existence of a Hermitian nonnegative-definite solution to the matrix equation AXB = C. Moreover, we derive a representation of a general Hermitian nonnegative-definite solution. We then apply our solution to two examples, including a comparison of our solution to a proposed solution by Zhang in [1] using an example problem given from [1]. Our solution demonstrates that the proposed general solution from Zhang in [1] is incorrect. We also give a second example in which we derive the general covariance structure so that two matrix quadratic forms are independent. 展开更多
关键词 Matrix Equation AXB = C Generalized Inverse Matrices Parallel Summable Matrices Symmetrization Device
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Spike-and-Slab Dirichlet Process Mixture Models 认领 引用 被引量：1
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作者 Kai Cui Wenshan Cui 《Open Journal of Statistics》 2012年第5期512-518,共7页
In this paper, Spike-and-Slab Dirichlet Process (SS-DP) priors are introduced and discussed for non-parametric Bayesian modeling and inference, especially in the mixture models context. Specifying a spike-and-slab bas... In this paper, Spike-and-Slab Dirichlet Process (SS-DP) priors are introduced and discussed for non-parametric Bayesian modeling and inference, especially in the mixture models context. Specifying a spike-and-slab base measure for DP priors combines the merits of Dirichlet process and spike-and-slab priors and serves as a flexible approach in Bayesian model selection and averaging. Computationally, Bayesian Expectation-Maximization (BEM) is utilized to obtain MAP estimates. Two simulated examples in mixture modeling and time series analysis contexts demonstrate the models and computational methodology. 展开更多
关键词 Spike and Slab Dirichlet Process Bayesian Expectation-Maximization (BEM) Mixture
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Investigating seasonality,policy intervention and forecasting in the Indian gold futures market:a comparison based on modeling non‑constant variance using two different methods 认领 引用
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作者 Rupel Nargunam William W.S.Wei N.Anuradha 《Financial Innovation》 2021年第1期1390-1404,共15页
This study focuses on the Indian gold futures market where primary participants hold sentimental value for the underlying asset and are globally ranked number two in terms of the largest private holdings in the physic... This study focuses on the Indian gold futures market where primary participants hold sentimental value for the underlying asset and are globally ranked number two in terms of the largest private holdings in the physical form.The trade of gold futures relates to seasons,festivity,and government policy.So,the paper will discuss seasonality and intervention in the analysis.Due to non-constant variance,we will also use the standard variance stabilization transformation method and the ARIMA/GARCH modelling method to compare the forecast performance on the gold futures prices.The results from the analysis show that while the standard variance transformation method may provide better point forecast values,the ARIMA/GARCH modelling method provides much shorter forecast intervals.The empirical results of this study which rationalise the effect of seasonality in the Indian bullion derivative market have not been reported in literature. 展开更多
关键词 Gold futures prices ARIMA models Non-constant variance ARCH and GARCH models Box-Cox power transformation Forecast errors
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Linear Dimension Reduction for Multiple Heteroscedastic Multivariate Normal Populations 认领 引用
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作者 Songthip T. Ounpraseuth Phil D. Young +2 位作者 Johanna S. van Zyl Tyler W. Nelson Dean M. Young 《Open Journal of Statistics》 2015年第4期311-333,共23页
For the case where all multivariate normal parameters are known, we derive a new linear dimension reduction (LDR) method to determine a low-dimensional subspace that preserves or nearly preserves the original feature-... For the case where all multivariate normal parameters are known, we derive a new linear dimension reduction (LDR) method to determine a low-dimensional subspace that preserves or nearly preserves the original feature-space separation of the individual populations and the Bayes probability of misclassification. We also give necessary and sufficient conditions which provide the smallest reduced dimension that essentially retains the Bayes probability of misclassification from the original full-dimensional space in the reduced space. Moreover, our new LDR procedure requires no computationally expensive optimization procedure. Finally, for the case where parameters are unknown, we devise a LDR method based on our new theorem and compare our LDR method with three competing LDR methods using Monte Carlo simulations and a parametric bootstrap based on real data. 展开更多
关键词 Linear Transformation Bayes Classification Feature Extraction Probability of Misclassification
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