Flexible nonhomogeneous markov models for panel observed data

Methods for fitting nonhomogeneous Markov models to panel-observed data using direct numerical solution to the Kolmogorov Forward equations are developed. Nonhomogeneous Markov models occur most commonly when baseline transition intensities depend on calendar time, but may also occur with deterministic time-dependent covariates such as age. We propose transition intensities based on B-splines as a smooth alternative to piecewise constant intensities and also as a generalization of time transformation models. An expansion of the system of differential equations allows first derivatives of the likelihood to be obtained, which can be used in a Fisher scoring algorithm for maximum likelihood estimation. The method is evaluated through a small simulation study and demonstrated on data relating to the development of cardiac allograft vasculopathy in posttransplantation patients.     

基于多目标线性规划的甲积峪小流域生态系统服务权衡优化

黄土高原是我国水土流失最严重的地区之一,区域生态系统服务退化。小流域是水土流失的主要发生地,在提升水土保持服务时如何权衡各类生态系统服务,是当前生态系统服务管理的重要内容。选取黄土高原典型小流域——甲积峪,以2012年为基准年,2022年为规划目标年,基于统计年鉴和调查数据,采用市场价值法、影子价格法、影子工程法、替代成本法和机会成本法对各土地利用类型的生态系统服务价值进行估算;采用多目标线性规划方法,将生态系统服务分为供给服务、水土保持服务与其他服务,以三者价值作为权衡子目标,生态系统服务总价值作为总目标构造目标函数,依据土地面积、粮油保障和各土地利用类型对坡度的适宜性,利用35个变量构造了17个约束方程,通过调整甲积峪土地利用类型实现小流域生态系统服务的权衡优化。结果表明,甲积峪生态系统服务价值主要受占地比例较大且生态系统服务价值较低的坡耕地和荒草地制约。权衡优化后,坡耕地和荒草地主要调整为生态系统服务价值较高的乔木林和梯田,土地利用结构得到明显改善。生态系统服务总价值增幅为9.23%,供给服务、水土保持服务与其他服务价值增幅分别为6.24%、9.81%和17.35%。三者增加量分别占生态系统服务总价值增加量的25.96%、54.42%和19.62%。与仅以供给服务、水土保持服务、其他服务或总服务价值为目标函数的优化结果相比,3个子目标的优化结果更加协调,且三大效益均明显增加。空间分布上,不同生态功能区的各生态系统服务价值增长率存在明显差异,上游其他服务价值增长率最高,中游水土保持服务价值增长率最高,下游供给服务和总服务价值增长率最高,与甲积峪上中下游生态功能区定位一致。充分考虑了土地利用适宜性,在保证供给服务的前提下,突出了水土保持服务并优化了其他服务,各综合治理效益评价指标均得到提高,符合黄土高原小流域的实际情况。     

上海市公立医院病人满意度状况和影响因素研究

通过病人满意度问卷调查,对上海市公立医院的门诊病人满意度和住院病人满意度进行了分析。调查结果显示,上海市公立医院病人满意度总体较高,且比上一年度有所提升,但三级专科医院的医疗服务质量相对较低。建议改进医院门诊服务流程、注重诊疗过程中的隐私保护,建立公立医院分级诊疗制度,进一步改善医疗服务质量。

     

大型综合医院医疗服务半径研究

目的：探讨大型医院神经内科医疗服务半径的基本情况及变化趋势,为科室健康发展、合理配置医疗资源提供科学依据,并以此为基础建立一个临床科室服务半径的分析模型。方法：利用军队医院信息管理系统中病案管理子系统建立数据库,对住院患者病案首页信息的基本情况进行单因素统计分析,并利用地理信息系统直观描述该院患者来源分布频率,定量研究医院服务半径的影响因素。结果：在2007—2010年收治的26528例地方患者中,男性多于女性,60岁以上老年人居多;本市住院病人数量呈逐年下降的趋势,而距离西安市较远的地区和外省病人数量呈逐年上升趋势。定量研究医院服务半径的影响因素发现,可能的影响因素有患者年龄、疾病病种、是否手术、住院日、医疗费用、医疗性质等方面（P〈0．05）。结论：在医疗服务市场竞争中,医院医疗服务半径的拓展与医疗服务满意度、社会经济发展、新医改的不断推进、品牌营销策略等影响因素密切相关。     

Integrated hospital and community psychiatric services and use of inpatient beds.

The impact of introducing a divisional psychiatric service based in the community in Nottingham in 1981 on adult psychiatric admissions (patients aged 15-65) was examined with data from the Nottingham case register. During 1980-5 the number of psychiatric admissions fell significantly (4.5% a year) compared with the national figures (0.46% a year). Admissions were reduced most for the diagnoses of affective psychosis and neurotic and personality disorders. The average duration of admission fell by 3.6% a year, and use of inpatient beds fell by 37.5%. Integrating hospital and community psychiatric services by creating sectors is a viable and economically feasible way of improving psychiatric services.     

森林固碳释氧服务价值与异养呼吸损失量评估

固碳释氧是森林最重要的生态系统服务之一,将森林碳收支与固碳释氧服务价值评估相结合对于准确评估生态系统服务价值具有重要意义。应用森林碳收支模型(CBM-CFS3),分别基于净初级生产力(NPP)和净生态系统生产力(NEP)评估了2009—2030年湖北省兴山县森林生态系统总、净固碳释氧服务价值的时空动态,量化了异养呼吸造成的固碳释氧服务价值损失。模拟期间兴山县森林生态系统NPP逐渐增加(0.46—0.70 Tg/a),NEP由0.12 Tg/a先增加至0.21 Tg/a,然后逐渐下降至0.18 Tg/a;所对应的森林总、净固碳释氧服务价值范围分别为7.59—11.53亿元/a和2.21—3.70亿元/a。异养呼吸逐年增加,导致固碳释氧价值每年损失平均值为7.29亿元/a或4509元hm~(-2) a~(-1),约占总价值的68.6%。兴山县东南部异养呼吸造成的森林固碳释氧服务价值损失较高,而中部及西南部森林净固碳释氧价值较高。模拟期间兴山县森林为碳汇,稳定地提供固碳释氧服务。与NPP相比,使用NEP评估固碳释氧服务价值更为合理。忽视异养呼吸将严重高估森林生态系统固碳释氧服务价值;因而必须将物质循环过程与生态系统服务评估相结合,以降低评估结果的不确定性、提高生态系统服务的评估能力。     

Development of a biologically-based controlled growth and differentiation model for developmental toxicology

 A mathematical model is developed with a highly controlled birth and death process for precursor cells. This model is both biologically- and statistically-based. The controlled growth and differentiation (CGD) model limits the number of replications allowed in the development of a tissue or organ and thus, more closely reflects the presence of a true stem cell population. Leroux et al. (1996) presented a biologically-based dose-response model for developmental toxicology that was derived from a partial differential equation for the generating function. This formulation limits further expansion into more realistic models of mammalian development. The same formulae for the probability of a defect (a system of ordinary differential equations) can be derived through the Kolmogorov forward equations due to the nature of this Markov process. This modified approach is easily amenable to the expansion of more complicated models of the developmental process such as the one presented here. Comparisons between the Leroux et al. (1996) model and the controlled growth and differentiation (CGD) model as developed in this paper are also discussed. Received: 8 June 2001 / Revised version: 15 June 2002 / Published online: 26 September 2002 Keywords or phrases: Teratology – Multistate process – Cellular kinetics – Numerical simulation     

Persistence in models of three interacting predator-prey populations

This paper considers a class of deterministic models of three interacting populations with a view towards determining when all of the populations persist. In analytical terms persistence means that liminf_t→∞x(t)> 0 for each population x(t); in geometric terms, that each trajectory of the modeling system of differential equations is eventually bounded away from the coordinate planes. The class of systems considered allows three level food webs, two competing predators feeding on a single prey, or a single predator feeding on two competing prey populations. As a corollary to the last case it is shown that the addition of a predator can lead to persistence of a three population system where, without a predator, the two competing populations on the lower trophic level would have only one survivor. The basic models are of Kolmogorov type, and the results improve several previous theorems on persistence.     

The Yad Sarah geriatric dental clinic, a different model

Introduction: There are not sufficient dental services for elderly people around the world. Yad Sarah is an Israel‐wide network of volunteers aiding sick, elderly, isolated and housebound people with an array of services aimed at making home care possible. It provides medical and social services to more than 380 000 elderly persons per year and in addition, lends medical equipment free of charge, has day rehabilitation centres, legal aid council for seniors, provides transportation for the disabled, meal deliveries and geriatric dental services. Materials and methods: The latter are equipped with five dental units (one mobile unit) and a dental laboratory. During the 5 years from 2000 to 2004 the dental services provided dental care for 3890 elderly patients with the main clinic located in Jerusalem. Patients pay an average of 70% of the cost price of their dental care, with the difference being subsidised by Yad Sarah. Of the 515 patients who applied for treatment in 2004, 54% possessed natural teeth in both jaws, 28% were fully edentulous, 12% were edentulous in the maxilla and 6% were edentulous in the mandible. Females applied for dental treatment more often than the male population. Older patients (75–101 years old) required oral care at their homes or at old age residences, more frequently than the younger age groups (60–74 years old). Conclusion: Dental treatment was administered by 70 volunteer dental surgeons, two certified dental hygienists and dental hygienist students. The clinical staff was provided with a comprehensive in‐service training in geriatric dentistry during the 3‐year service learning period. A survey in 2004 showed that 83% of the selected patients were satisfied, compared with 14% who were not. The reasons for satisfaction were, mainly, the personal relationship with the attending staff (41%) and the professional ability of the dental team (46%).     

The clinical psychologist in a health centre: one year's work.

The Livingston integrated health services project is an attempt to provide a fully integrated area health service with special emphasis on developing multidisciplinary community health teams. As part of this experiment a clinical psychologist was appointed to work in general practice. Ninety-four patients with behavioural, emotional, and cognitive problems were referred in the first year (1% of the 10 000 patients registered at the practice). The psychologist thus provided treatment for some patients who would otherwise have been seen by a general practitioner with neither the time nor the training to deal adequately with their problems.     

Out-of-hours calls in a Leicestershire practice.

In one year, 920 "out-of-hours" calls were received by a partnership of three general practitioners working from a health centre in semi-rural Leicestershire. The partners on duty saw 588 patients. Out of 898 patients on whom information was available only 75 (8-5%) were referred to hospital, mainly as casualties. The results are compared with a study of deputising services, and it is concluded that a partnership covering its own out-of-hours calls can provide a more personal service and appears to make fewer demands on NHS resources.     

Mathematical description of modifying synapses of hippocampal pyramidal neurons

The system of differential equations describing the plasticity of the hippocampal pyramidal neuron CA3, developed before, was analyzed. The system was divided into two groups according to magnitudes of the biochemical reaction constants. The first group with large values of the constants was transformed into quasi stationary algebraic equations. This allowed one to transform the system of 32 differential equations to a system containing only 4 differential equations, which can be used for modeling of learning processes in various parts of the brain.     

无缝隙对接服务工程中医疗服务管理理念的探究

目的:探究创新医疗卫生服务管理理念的开展、实施无缝隙对接服务工程的成果以及具体方法。方法:对本院2013年1月-2013年12月期间的门诊量、出住院病人数、人均住院天数、患者满意度等资料进行回顾性的分析,对采用无缝隙对接服务工程的前、后的成果进行对比研究。结果:2013年1月-2013年12月期间本院门诊量、出院人数较去年同期分别增长了9.19%和14.0%;患者平均住院12.1 d,同比减少了0.7 d;患者满意度达到了98.7%,接到投诉312次,同比减少了200余次。结论:无缝对接工程的实施,改造并创新了医疗服务管理的理念,对于提高患者满意度,实现了社会、经济效益的双收具有积极意义。     

贵州省生态系统服务价值时空演变及其对景观格局变化的响应

贵州省是我国生态文明试验区,也是世界上岩溶地貌发育最典型的地区之一,探明其生态系统服务价值变化及其与景观格局在空间上的相关性分布特征,有利于因地制宜地制定生态环境治理和保护措施。本研究分析了2005—2018年间贵州省景观格局和生态系统服务的时空变化,并构建二者之间的地理加权回归模型,探讨其相关系数在空间上的变化。结果表明: 2005—2018年间,贵州省景观类型的转移主要发生在建设用地、森林、水域、草地和农田5种景观之间,景观破碎度和多样性增加;生态系统服务价值逐年增长,森林是贵州省生态系统服务价值的主要贡献者,生态系统服务以调节服务为主;对于高价值景观类型而言,多样性提升和破碎度降低有利于生态系统服务价值增长;而在低价值景观类型集中的区域,则呈现出相反的影响效果。应根据贵州省不同区域的生态环境特征,调整景观转移方向和不同景观类型的多样性和破碎度空间分布,从而实现生态系统服务价值增长。     

Organisation of primary care services outside normal working hours.

OBJECTIVE--To determine the use and organisation of out of hours services in primary care. DESIGN--Telephone survey. SETTING--Family health services authorities in England and Wales. MAIN OUTCOME MEASURES--Rate of use of out of hours care, methods of provision, and role of authorities. RESULTS--12-25% of authorities were unable to answer one or more key questions in the survey because of insufficient information. The mean number of night visits made per unrestricted principal per 1000 patients per year was 35.3. 13 of the 19 authorities with averages above 40 covered large towns or cities. 81 authorities had at least one commercial deputising service. In 46 metropolitan districts and one other district over 75% of general practitioners had consent to use a deputising service, although not all did so. Information on cooperation between practices was limited. 22 cooperatives were recognised by the authorities, nine were not officially recognised, and a further 13 were nearing institution. Only two cooperatives were in areas with extensive use of deputising services. CONCLUSION--Methods of providing out of hours care are changing, and without good information systems family health services authorities will not be able to monitor the effect on quality and cost effectiveness of care.     

Stochastic models for the Trojan Y-Chromosome eradication strategy of an invasive species

The Trojan Y-Chromosome (TYC) strategy, an autocidal genetic biocontrol method, has been proposed to eliminate invasive alien species. In this work, we develop a Markov jump process model for this strategy, and we verify that there is a positive probability for wild-type females going extinct within a finite time. Moreover, when sex-reversed Trojan females are introduced at a constant population size, we formulate a stochastic differential equation (SDE) model as an approximation to the proposed Markov jump process model. Using the SDE model, we investigate the probability distribution and expectation of the extinction time of wild-type females by solving Kolmogorov equations associated with these statistics. The results indicate how the probability distribution and expectation of the extinction time are shaped by the initial conditions and the model parameters.     

A simple parasite model with complicated dynamics

 During their first year of life sheep acquire parasites through grazing, and simultaneously build up an immunity to infection. At the beginning of each year non-immune lambs are introduced onto contaminated pasture. We represent this process by differential equations describing the within-year dynamics, and defining a difference equation that describes the between-year dynamics. An example with two system parameters is analysed in detail. It is shown that regions exist in parameter space where periodic (between-year) or aperiodic solutions occur. Parasite control schemes could change the system dynamics from a stable equilibrium to complicated long-term fluctuations. Received: 11 August 1997 / Revised version: 4 December 1997     

On the accuracy of a diffusion approximation to a discrete state–space Markovian model of a population

The traditional Kolmogorov equations treat the size of a population as a discrete random variable. A model is introduced that extends these equations to incorporate environmental variability. Difficulties with this discrete model motivate approximating the population size as a continuous random variable through the use of diffusion processes. The set of cumulants for both the population size and the environmental factors affecting the population size characterize the population–environmental system. The evolution of this set, as predicted by the diffusion approximation, closely matches the corresponding predictions for the discrete model. It is also noted that the simulation estimates of the cumulants against which the predictions of the diffusion model are checked can vary considerably between simulations — despite averaging over a large number of simulation runs. The precision of the simulation estimates–both over time and with differing cumulant order–is discussed.     

A new cloud-based classification methodology (CBCM) for efficient semantic web service discovery

Over the last decades, web services are used for performing specific tasks demanded by users. The most important task of service’s classification system is to match an anonymous input service with the stored pre-classified web services. The most challenging issue is that web services are currently organized and classified according to syntax while the context of the requested service is ignored. Due to this motivation, Cloud-based Classification Methodology is proposed as it presents a new methodology based on semantic web service’s classification. Furthermore, cloud computing is used for not only storing but also allocating the high scale of web services with both high availability and accessibility. Fog technology is employed to reduce the latency and to speed up response time. The experimental results using the suggested methodology show a better performance of the proposed system regarding both precision and accuracy in comparison with most of the methods discussed in the literature of the current study.

     

Community care for patients with schizophrenia one year after hospital discharge.

OBJECTIVES--To document the circumstances and care of patients with schizophrenia who had recently been discharged from local psychiatric inpatient services, and to establish the extent to which misgivings about community care might be justified. DESIGN--Cross sectional surveys with review of case notes. Follow up interviews with questionnaires administered one year after discharge. SETTING--Two inner London districts (West Lambeth and Lewisham) with high levels of social deprivation and at different stages of developing community services. PATIENTS--90 and 50 patients in the two services respectively, aged 18 to 65, who satisfied the Research Diagnostic Criteria for schizophrenia and who were discharged from inpatient services. MAIN OUTCOME MEASURES--Diagnosis elicited by present state examination, global social disability rating, use of services during the three months before interview. RESULTS--89 of the 140 patients (64%) had been ill for five or more years, yet few were former long stay inpatients. 55% (50/91; 95% confidence interval 45% to 65%) of those interviewed had current psychotic mental states and 22% (27/124; 16% to 31%) were functioning socially at very poor or severely maladjusted levels. 86% (107/124) were unemployed. The majority of patients had seen a mental health or social service professional, yet only 16% (20/124) were in specialised accomodation (excluding hospitals) and only 23% (17/73) of those eligible had used day care. Small numbers of people had experienced homelessness (two) or imprisonment (four over six months). CONCLUSIONS--Many schizophrenic patients leaving local psychiatric inpatient care have active symptomatology and profound social disabilities. Community care was characterised by high rates of contact with service professionals but little supported accommodation or day activity. This group of clients may require dedicated provision, which would actively encourage them to use services protected from the demands of those with less severe illness.