一类带有隔离和接种模型的稳定性

讨论了一类带有隔离和接种并且具有非线性传染率βSI/H+I的SIQR模型,证明了无病平衡点和地方病平衡点的存在性及全局渐进稳定性;揭示了隔离和接种对传染病控制的积极作用.     

一类具有连续预防接种的SIR传染病模型

研究了具有连续预防接种和垂直传染SIR传染病模型,获得了疾病绝灭和持续的基本再生数σ,证明了当σ＜1时仅有无病平衡点存在,全局渐近稳定;当σ＞1时无病平衡点不稳定,地方病平衡点存在,全局渐近稳定.     

一类带有隔离的SIQR模型

讨论了一类带有隔离并且具有非线性传染率βSI/1+CI3的SIQR模型,获得了该传染率下的基本再生数,证明了无病平衡点和地方病平衡点的存在性及渐进稳定性.     

一类具有常数移民的SIQR和SIQS组合流行病模型

研究一类具有隔离项及常数移民的SIQR和SIQS组合流行病模型,得到疾病是否流行的基本再生数,证明了无病平衡点和地方病平衡点的存在性和全局稳定性。     

带潜伏期和年龄结构流行病模型的稳定性

根据肺结核的传播特点,建立了带潜伏期和潜伏年龄的数学模型.证明了当基本再生数R0<1时,系统无病平衡点是局部和全局渐近稳定的;当R0>1时,无病平衡点不稳定,此时系统存在一个地方病平衡点,并证明了该地方病平衡点是局部渐近稳定的.     

一类具有非线性传染率的SEIR模型的定性分析

建立并分析一类具有潜伏期的传染病模型,得到了基本再生数R0,当R0>1时,患病人数增加,当R0<1时,患病人数减少且趋于0.     

一类具有双线性发生率的SEIR流行病传播数学模型

利用Lasalle不变集原理探讨系统的渐近性态，研究了一类具有双线性发生率且染病期传染的SEIR流行病传播数学模型的动力学性质．得到了疾病绝灭与持续的阈值一基本再生数，证明了无病平衡点的全局渐近稳定性和地方病平衡点的全局渐近稳定性，揭示了潜伏期传染的影响．     

一类具有常数移民且带隔离项的传染病模型的分析

隔离是防治传染病的有效方法,在控制传染病的过程中有相当重要的意义.利用传染病动力学来建立传染病模型,可以比较准确地描述传染病流行时人群中各类人数的变化,再通过一些数学软件则能形象地反映其中的规律.因此从数学的角度来分析,在传染病发生过程中各因素对于疾病防治具有重要作用.     

具有阶段结构和饱和治疗的SIS模型的动力学性态

该文研究了一类具有阶段结构的SIS传染病模型,包括：定义了模型的基本再生数：讨论了模型的无病平衡点和地方病平衡平衡点的存在性;证明了无病平衡点和地方病平衡点的局部渐近稳定性;发现了饱和治疗会引起后向分支。     

无疾病潜伏期的传染病动力学模型的阈值和再生数分析

给出了无疾病潜伏期的传染病动力学模型的基本形式，通过对SIR有垂直传染且康复者的新生儿不具免疫力模型和SIR无垂直传染而引入疫苗接种模型的阈值和再生数分析，说明了阈值和再生数R0=1的差异。     

一种基于非负矩阵隐特征分析的Web服务QoS预测模型

提出了一种受非负条件约束、基于不完全矩阵隐特征分析的协同过滤模型,用以在非负条件约束下,预测未知的Web服务QoS(quality-of-service)数据。其主要原理是,将非负矩阵因式分解模型中基于矩阵操作的非负更新规则,扩展为只依赖于单一隐特征的非负更新规则,以获得仅依赖于所需模型中单一隐特征、以及目标稀疏矩阵中已知元素的非负训练过程。为提高最终模型的预测精度,模型中进一步引入了Tikhonov正则化,并对隐特征的非负更新规则进行了相应扩展。在2个大型Web服务QoS数据集上的实验表明,该模型能在满足非负条件约束的前提下,准确地预测未知的QoS数据。     

A multi-user virtual environment to support students' self-efficacy and interest in science: A latent growth model analysis

Using latent growth models, we explored: (a) The effect of middle school students' (n = 189) pre-intervention science self-efficacy and science interest on their initial interest in an Ecosystems Multi-User Virtual Environment (EcoMUVE) and the rate of change in their interest in EcoMUVE; and (b) the mediating effect of students' initial interest in EcoMUVE and rate of change in interest on students' post-intervention science self-efficacy and interest in science. Results showed that: (1) students' pre-intervention self-efficacy for science had an effect both on students' triggered situational interest for EcoMUVE and on students' maintained situational interest for EcoMUVE; (2) both triggering and maintaining situational interest in EcoMUVE were important in developing students' science self-efficacy. In fact, maintained situational interest was the stronger predictor; and (3) maintained situational interest for EcoMUVE translated into individual interest for the science content. Results support and extend social cognitive theory as well as models of interest development.     

Teacher effect change model: latent variable regression 5-level hierarchical model

Asia Pacific Education Review - This paper proposes a teacher effect change model in the form of a latent variable regression 5-level hierarchical model (LVR-HM5). Using multiple years of student...     

Trajectories of post-traumatic stress and externalizing psychopathology among maltreated foster care youth: A parallel process latent growth curve model

Few longitudinal studies have analyzed how violence exposure (e.g. child maltreatment, witnessing community violence) influence both externalizing and Post-Traumatic Stress (PTS) symptoms among children in foster care. Data from three waves of the National Survey of Child and Adolescent Well-Being (1999–2007) (NSCAW; National Data Archive on Child Abuse and Neglect, 2002) were analyzed to investigate the change trajectories of both externalizing and PTS symptomatology among children with a substantiated report of child maltreatment by Child Protective Services (CPS) between October 1999 and December 2000. This study uses data collected at three time points: baseline and approximately 18 (Wave 3) and 36 (Wave 4) months post-baseline. The Child Behavior Checklist (CBCL) scale measured externalizing symptoms and the Post Traumatic Stress Disorder section of a version of the Trauma Symptom Checklist for Children (TSCC) provided the measure of current trauma-related symptoms or distress. Analyses were conducted using a parallel process growth curve model with a sample of n = 280 maltreated youth between the ages of 8 and 15 following home removal. Findings revealed that initial levels of externalizing and PTS symptomatology were both significantly and positively related and co-develop over time. Externalizing symptom severity remained in the borderline range during the first two years in out-of-home care. Both direct and indirect forms of interpersonal violence exposure were associated with initial level of externalizing symptom and PTS symptom severity, respectively. Taken together, our results suggest an underlying process that links early violence exposure to the co-development and cumulative impact of PTS on externalizing behavior above and beyond experiences of maltreatment. We conclude by discussing the key points of intervention that result from a more nuanced understanding of the longitudinal relationship between PTS and externalizing symptoms and the effect of complex trauma on growth in these symptoms over time.     

Teachers' enthusiasm and humor and its' lagged relationships with students' enjoyment and boredom - A latent trait-state-approach

Following Pekrun's (2006) control-value theory of achievement emotions, we investigated carry-over effects and cross-lagged relationships between student-perceived teacher enthusiasm and humor and students' enjoyment and boredom both within and between university lectures. We used a latent state-trait approach to acknowledge the role of situational factors in this relationship. Data were collected from 559 university students (76% female, mean age 21.6 years) from seven different lecture courses. We assessed students' self-reported emotions and student-perceived teacher enthusiasm and content-related humor over a period of four lectures at three random points during each lecture course. The analyses revealed that all variables were influenced by previous measures within lectures; however, between lectures, only previous enjoyment and humor influenced the subsequent measure. When students experienced boredom, they perceived less teacher enthusiasm and humor. On the other hand, perceived teacher humor positively affected enjoyment within lectures.     

Abilities and skill acquisition: A latent growth curve approach

The relationship between abilities and skill acquisition has been the subject of numerous controversies in psychology. However, while most researchers implicitly or explicitly accept the idea that abilities and skill acquisition should be related, empirical research has failed to provide evidence for a consistently strong correlation between the two constructs. Based on the reanalysis of a study on skill acquisition using the air traffic controller task TRACON [Ackerman, P. L., Kanfer, R., and Goff, M. (1995). Cognitive and Noncognitive Determinants and Consequences of Complex Skill Acquisition. Journal of Experimental Psychology. Applied, 1(4), 270–304], it will be shown how latent growth curve modeling can help to gain a better understanding of the relationship between human abilities and skill acquisition. A brief introduction into the basic concepts of latent growth curve modeling will be given, particularly with regard to the advantages for the analysis of skill acquisition and its determinants. The goal is thereby to provide evidence for a much closer association than commonly assumed and to offer a new, differential, perspective formerly obscured by traditional between-subject analyses.     

Identifying dyslexia with confirmatory latent profile analysis

Confirmatory latent profile analysis (CLPA) was used with the normative sample from the Kaufman Test of Educational Achievement, 3rd ed. (KTEA‐3) to determine whether it was possible to identify a latent class of individuals whose scores were consistent with the academic strengths and weaknesses related to dyslexia. The CLPA identified a class of individuals consistent with dyslexia across four‐grade level groups (first–second, third–fifth, sixth–eighth, and ninth–twelfth). The results of the CLPA were applied to the KTEA‐3 clinical samples of those with known clinical diagnoses. Individuals with Specific Learning Disorder in Reading and/or Written Expression had a higher probability of being in the dyslexia latent class. The use of CLPA as a tool for learning disability diagnosis appears plausible, though much more research is needed. The strengths, limitations, and future directions for the use of CLPA in diagnosis are discussed.     

Release from latent inhibition with delayed testing

A conditioned emotional response procedure was used to study the interactive effects of stimulus preexposure and retention interval in rats. In Experiment 1, the subjects were conditioned by presenting a light CS paired with mild footshock as the US. Half of the subjects were given nonreinforced preexposure to the CS, and the others were not. Separate preexposed and nonpreexposed groups were then tested 1,7, or 21 days after conditioning. Suppression of ongoing activity was used to assess the degree of conditioned fear. Latent inhibition was found at the 1-day retention interval; the preexposed subjects displayed less conditioned fear than did the nonpreexposed subjects. In contrast, equally strong conditioned fear was expressed by the preexposed and the nonpreexposed groups tested after the 7- and the 21-day retention intervals. These results indicate a release from latent inhibition similar to that obtained with conditioned taste aversions (Kraemer & Roberts, 1984). The results of Experiment 2 suggest that retention-interval-induced increases in sensitization, pseudoconditioning, or neophobia cannot account for the release from latent inhibition effect obtained in Experiment 1. The implications of these findings for a retrievaloriented view of latent inhibition are discussed.     

Identifying maltreatment subgroups with patterns of maltreatment subtype and chronicity: A latent class analysis approach

Maltreatment experiences are complex, and it is difficult to characterize the heterogeneity in types of maltreatment. Subtypes, such as emotional maltreatment, sexual abuse, physical abuse, and neglect commonly co-occur and may persist across development. Therefore, treating individual maltreatment subtypes as independently occurring is not representative of the nature of maltreatment as it occurs in children’s lives. Latent class analysis (LCA) is employed herein to identify subgroups of maltreated children based on commonalities in maltreatment subtype and chronicity. In a sample of 674 low-income urban children, 51.6% of whom experienced officially documented maltreatment, our analyses identified four classes of children, with three distinct classes based on maltreatment subtypes and chronicity, and one group of children who did not experience maltreatment. The largest class of maltreated children identified was the chronic, multi-subtype maltreatment class (57% of maltreated children); a second class was characterized by only neglect in a single developmental period (31% of maltreated children), and the smallest class was characterized by a single subtype of maltreatment (emotional maltreatment, physical, or sexual abuse) occurring in a single developmental period (12% of maltreated children). Characterization of these groups confirms the overlapping nature of maltreatment subtypes. There were notable differences between latent classes on child behavioral and socio-emotional outcomes measured by child self-report and camp counselors report during a one-week summer camp. The largest differences were between the non-maltreated class and the chronic maltreatment class. Children who experienced chronic, multi-subtype maltreatment showed higher levels of externalizing behavior, emotion dysregulation, depression, and anxiety.     

A latent profile analysis of student restudy decisions

Metacognition and Learning - Do all learners make the same restudy decisions, or is there heterogeneity within the population? The present study combines three previously published datasets and...