视场非完全重叠的分布式雷达多目标跟踪方法

在探测能力、波形设计及天线指向等因素制约下,分布式雷达视场并非完全重合,由此造成的观测信息差异给后续信息融合带来了巨大挑战。该文基于高斯混合实现的集势概率假设密度(CPHD)滤波器,提出了一种视场部分重叠下的分布式雷达多目标跟踪方法。首先,利用多目标密度乘积切分出概率假设密度(PHD)中表征共同观测信息的部分;之后,标准的分布式融合(算术平均或几何平均融合)方法作用于切分出的共同观测目标信息以提升跟踪性能,补偿融合则作用于雷达单独观测目标信息以扩展视场范围。该文方法无须视场先验信息,能够适应雷达视场未知时的分布式融合多目标跟踪场景。仿真实验验证了所提出方法在未知、时变雷达视场下跟踪多目标的性能,表明了该文方法比基于高斯混合的聚类方法性能更好。      

硅基单结太阳能电池的制备技术、缺陷及其性能的研究

首先综述了硅基单结太阳能电池的分类、制备方法及进展,介绍了化学气相沉积法、液相外延法(LPPE)、金属诱导结晶法(MIC)、磁控溅射法以及分子束外延法等各种硅基太阳能电池的制备方法,阐述了各种制备工艺的优缺点。其次,总结了单晶硅、多晶硅以及非晶硅太阳能电池在组织结构、缺陷方面的研究现状。最后,对硅基太阳能电池的机械、电学、光学以及光电性能等方面的研究进展做了论述。     

高性能混凝土结构在热带海洋环境下的服役寿命

近些年,高性能混凝土以其高强度,高抗渗性、抗冻融性、耐腐蚀性的特点得到了越来越广泛的应用。本文通过实验所得数据,简要分析了高性能混凝土在南海热带海洋环境下对混凝土结构服役寿命的影响。结果表明:运用高性能混凝土能大幅度延长混凝土结构的使用寿命。对于港口、防波堤等结构,在热带海洋环境下按照现行规范《水运工程混凝土施工规范》(JTS 202-2011)中规定的最小保护层厚度(65mm)进行设计,不能达到50年的寿命要求,必须增加保护层的厚度至75mm,或者施加附加防护措施,才能满足寿命要求。     

Gains and losses of the XII-VII component of the "baby-sitter" procedure: a morphometric analysis

The classic hypoglossal transfer to the facial nerve is invariably followed by complications caused by tongue atrophy. In 1984, Terzis introduced the "baby-sitter" procedure which involved a formal cross-facial procedure, in addition to partial neurectomy of the hypoglossal nerve, and an end-to-side coaptation with the ipsilateral facial nerve. This reported study provides, for the first time, quantification of the number of hypoglossal motor fibers needed to successfully restore eye sphincter function, using an end-to-side coaptation with preservation of the tongue. Thirty adult Sprague-Dawley rats were divided into six groups: control, denervated, perineurial window, 20 percent partial neurectomy (PN), 40 percent PN, and 80 percent PN. The procedure involves interposing a nerve graft (saphenous) between the partially severed XII nerve and the upper zygomatic branch of the facial nerve. Evaluation of the behavioral data (blink reflex) revealed good-to-superb return of the blinking mechanism in the 40 percent group, without significant tongue atrophy. Electrophysiologic data in the 40 percent neurectomy group demonstrated superiority to the other groups. Quantitative axonal morphometry of the coaptation sites and graft, as well as motor end-plates of the orbicularis oculi muscle and tongue showed the 40 percent partial neurectomy group to be the optimal group.     

Are there cognitive subtypes in adult attention deficit/hyperactivity disorder?

There has been increasing knowledge of the treatment, diagnosis, and demographics of adults with residual attention deficit/hyperactivity disorder (ADHD). However, less is known about the neuropsychological functioning in adults with residual ADHD. In comparing the clinical neuropsychological test performance of a group of adult clinic patients with residual ADHD (N = 30) with that of normal controls (N = 10), we found the patients performed worse on the Trail Making Test, a visual continuous performance test, and the "Brown-Peterson" Auditory Consonant Trigrams Test, but not on any other neuropsychological measures. This pattern indicated a deficit in the area of executive control type functioning, a functional deficit that could be linked to dysregulation of frontal lobe brain systems. Of equal interest was that patients diagnosed with ADHD/hyperactive impulsive type (ADHD+) and patients diagnosed with ADHD/inattentive type (ADHD-) had different types of executive system deficits. ADHD+ was associated with relative deficiency on the Wisconsin Card Sorting Test. ADHD- was associated with relative deficiency on the "Brown-Peterson" Auditory Consonant Trigrams Test, a measure of working memory, as well as less olfactory identification on a smell identification test. The data are discussed in terms of recent localization theories of frontal lobe function. The preliminary data suggest that the different cognitive weaknesses of ADD subtypes may be linked to dysregulation of separate frontal brain regions and/or neurotransmitter systems.     

RasGRP, a Ras guanyl nucleotide- releasing protein with calcium- and diacylglycerol-binding motifs

RasGRP, a guanyl nucleotide-releasing protein for the small guanosine triphosphatase Ras, was characterized. Besides the catalytic domain, RasGRP has an atypical pair of "EF hands" that bind calcium and a diacylglycerol (DAG)-binding domain. RasGRP activated Ras and caused transformation in fibroblasts. A DAG analog caused sustained activation of Ras-Erk signaling and changes in cell morphology. Signaling was associated with partitioning of RasGRP protein into the membrane fraction. Sustained ligand-induced signaling and membrane partitioning were absent when the DAG-binding domain was deleted. RasGRP is expressed in the nervous system, where it may couple changes in DAG and possibly calcium concentrations to Ras activation.     

Differences between completers and early dropouts from 2 HIV intervention trials: a health belief approach to understanding prevention program attrition

OBJECTIVES: The purpose of this study was to identify factors predicting program attrition among participants in human immunodeficiency virus (HIV) risk reduction trials. METHODS: Participants were gay/bisexual men and severely mentally ill adults recruited to take part in HIV risk reduction small-group interventions. Program completers were compared with participants who were assessed at baseline but then failed to attend any sessions. The health belief model provided a framework for selection of possible predictors of program attrition. RESULTS: Younger age was associated with early dropout in both samples. Other predictors among gay/bisexual men included involvement in an exclusive sexual relationship, minority ethnicity, injection drug use, and higher perceived severity of AIDS. Severely mentally ill dropouts were less knowledgeable about safer sex methods and more likely to hold positive outcome expectancies for condom use. CONCLUSIONS: Evaluation of intervention effectiveness among vulnerable population segments is threatened if there is selective attrition. Better methods are needed to attract and maintain participation in HIV prevention programs. Alternatively, wider application of "intention to treat" analysis of intervention outcomes is recommended to minimize selection bias due to program dropout.     

Detection and characterization of the electron paramagnetic resonance-silent glutathionyl-5,5-dimethyl-1-pyrroline N-oxide adduct derived from redox cycling of phenoxyl radicals in model systems and HL-60 cells

Rapidly growing knowledge about the nature and behaviour of breast cancer has led to many treatment modalities. Consequently, the possibilities of individualizing the treatment of breast cancer increase. The major tool for the determination of an optimal treatment plan is the estimation of the extent of the disease: in other words, staging. As a consequence, together with the expected result of the treatment, the stage of the disease gives information on the prognosis of the patient. Current staging systems insufficiently describe the clinically important features of breast cancer with respect to management and outcome: local and regional extent, invasiveness, aggressiveness, the state of dissemination, and the effectiveness of different treatment modalities. For staging of the local and regional extent, histology plays a prominent role and should be incorporated in future staging systems. Histological workup therefore needs standardisation. Histological parameters as tumour size, grade, nodal status, and vascular invasion are also the most important prognostic factors. Many so-called biological prognostic factors are related to the invasiveness and aggressiveness (metastatic potential) of the tumour, and therefore to the prognosis of the patient. However, these factors do not necessarily predict the effectiveness of certain systemic treatments. Only if the biological foundation of a prognostic factor is completely clarified can treatment be based on this knowledge, and the factor will become a predictor for the treatment effect. Many "biological" prognostic factors do not fulfil this main criterion and are therefore not useful for clinical decision making. A clinically useful staging system covers three primary aims: (1) to guide locoregional treatment, (2) to prognosticate the chance of survival, and (3) to indicate who needs what kind of adjuvant treatment. For the conception of a new staging system the following steps should be taken: standardization of all aspects of histology, identification of regional nodal involvement, and validation of prognostic factors with respect to their predictive value to treatment outcome.