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关键词： GENE-EXPRESSION DATA   MICROARRAY-BASED CLASSIFICATION   BREAST-CANCER   BIAS  

摘要： Motivation: Estimation of misclassification error has received increasing attention in clinical diagnosis and bioinformatics studies, especially in small sample studies with microarray data. Current error estimation methods are not satisfactory because they either have large variability (such as leave-one-out cross-validation) or large bias (such as resubstitution and leave-one-out bootstrap). While small sample size remains one of the key features of costly clinical investigations or of microarray studies that have limited resources in funding, time and tissue materials, accurate and easy-to-implement error estimation methods for small samples are desirable and will be beneficial. Results: A bootstrap cross-validation method is studied. It achieves accurate error estimation through a simple procedure with bootstrap resampling and only costs computer CPU time. Simulation studies and applications to microarray data demonstrate that it performs consistently better than its competitors. This method possesses several attractive properties: (1) it is implemented through a simple procedure;(2) it performs well for small samples with sample size, as small as 16;(3) it is not restricted to any particular classification rules and thus applies to many parametric or non-parametric methods.

关键词： fraud detection   wine vinegar   molasses vinegar   NIR spectroscopy   orthogonal signal correction   potential functions  

摘要： The most common fraudulent practice in the vinegar industry is the addition of alcohol of different origins to the base wine used to produce wine vinegar with the objective of reducing manufacturing costs. The mixture is then sold commercially as genuine wine vinegar, thus constituting a fraud to consumers and an unfair practice with respect to the rest of the vinegar sector. A method based on near-infrared spectroscopy has been developed to discriminate between white wine vinegar and alcohol or molasses vinegar. Orthogonal signal correction (OSC) was applied to a set of 96 vinegar NIR spectra from both original and artificial blends made in the laboratory, to remove information unrelated to a specific response. The specific response used to correct the spectra was the extent of adulteration of the vinegar samples. Both raw and corrected NIR spectra were used to develop separate classification models using the potential functions method as a class-modeling technique. The previous models were compared to evaluate the suitability of near-infrared spectroscopy as a rapid method for discrimination between vinegar origin. The transformation of vinegar NIR spectra by means of an orthogonal signal-correction method resulted in notable improvement of the specificity of the constructed classification models. The same orthogonal correction approach was also used to perform a calibration model able to detect and quantify the amount of exogenous alcohol added to the commercial product. This regression model can be used to quantify the extent of adulteration of new vinegar samples.

关键词： food contamination   mercury seafoods  

摘要： The objectives of this investigation were to determine the mercury content inan assortment of commercially available processed tuna samples and unprocessed fish fillet andseafood samples by applying a direct mercury analysis technique. The mercury concentrations in theprocessed tuna products ranged from 0.0329 to 0.412 mg/kg. Significant variability in the measuredmercury content was observed across all tuna packing and packaging methods, even for products fromthe same manufacturer. Products that were labelled to contain albacore tuna generally had highermercury levels than products that were labelled to contain light tuna, although overlap in mercurycontent was observed. The mercury content of fish fillets ranged from 0.00351 to 1.85 mg/kg. Thedetermined mercury concentrations for the catfish fillet, tilapia fillet, shrimp, and scallopsamples were all relatively low (<0.0400 mg/kg) compared to the other unprocessed seafood *** tuna and swordfish fillet samples had higher mercury content relative to the test samples, withconcentrations ranging from 0.0833 to 0.575 mg/kg and 0.872 to 1.85 mg/kg for tuna and swordfish,respectively..

关键词： microarray analysis   fine-needle aspiration biopsy   gene expression profile   tumor classifier   RNA  

摘要： BACKGROUND. Gene expression profiling using gene-discovery, high-density microarray technologies is a powerful tool. One potential application is the development of tumor classifiers that predict the site of origin. For this technology to be relevant, however, it must be applicable to tumor biopsy samples, which most often are fine-needle aspiration biopsy (FNAB) samples. METHODS. Surgically resected tumors were sampled by FNAB using different gauge needles. A portion of the excised tumor was also collected. RNA samples were extracted using standard techniques and the quality and quantity of the RNA samples were measured for each sample. Thirteen representative FNAB samples and two representative tissue samples were submitted for microarray analysis and then subjected to a tumor classifier. RESULTS. Fourteen of 18 samples analyzed for quantity and quality of RNA yielded an adequate amount of RNA (> 1 mu g total RNA). Tumor type contributed to the RNA yield because one of the four inadequate samples was retrieved from a patient with lobular carcinoma of the breast and the other three samples were retrieved from patients with retroperitoneal sarcomas. Of the 13 samples submitted for microarray analysis, 9 were classified correctly as to tumor type using a tissue-based tumor classifier. CONCLUSIONS. The authors demonstrated that FNABs reproducibly obtained an adequate amount of RNA for microarray analysis when a standardized collection procedure was used. Furthermore, the samples generated interpretable gene expression profiles that could be matched accurately with a tumor classifier established on tissue specimens. The current study showed that FNAB produced adequate material for microarray analysis when utilizing a standardized collection procedure. Cancer (Cancer Cytopathol) 2005;105:101-9. (c) 2005 American Cancer Society.

关键词： FEATURE-SELECTION   BREAST-CANCER   PERFORMANCE   CLASSIFIERS  

摘要： Motivation: Given the joint feature-label distribution, increasing the number of features always results in decreased classification error;however, this is not the case when a classifier is designed via a classification rule from sample data. Typically (but not always), for fixed sample size, the error of a designed classifier decreases and then increases as the number of features grows. The potential downside of using too many features is most critical for small samples, which are commonplace for gene-expression-based classifiers for phenotype discrimination. For fixed sample size and feature-label distribution, the issue is to find an optimal number of features. Results: Since only in rare cases is there a known distribution of the error as a function of the number of features and sample size, this study employs simulation for various feature-label distributions and classification rules, and across a wide range of sample and feature-set sizes. To achieve the desired end, finding the optimal number of features as a function of sample size, it employs massively parallel computation. Seven classifiers are treated: 3-nearest-neighbor, Gaussian kernel, linear support vector machine, polynomial support vector machine, perceptron, regular histogram and linear discriminant analysis. Three Gaussian-based models are considered: linear, nonlinear and bimodal. In addition, real patient data from a large breast-cancer study is considered. To mitigate the combinatorial search for finding optimal feature sets, and to model the situation in which subsets of genes are co-regulated and correlation is internal to these subsets, we assume that the covariance matrix of the features is blocked, with each block corresponding to a group of correlated features. Altogether there are a large number of error surfaces for the many cases. These are provided in full on a companion website, which is meant to serve as resource for those working with small-sample classification.

关键词： 包装废弃物   征税   分类   上海   白色污染  

摘要： 在控制白色污染方面走在全国前列的上海,将再出新举--对各类包装废弃物实行分类征税.日前,由上海市政府参事室与上海市环保工业行业协会联合主办的食品包装在循环经济中的可持续发展研讨会上,与会专家提出应对上海市各类包装废弃物实行分类征税的建议.建议得到上海市人大的响应.

关键词： 经济增长趋势   经济周期   波动性   作用机制   经济增长速度   “溢出效应”   经济增长水平   正相关性   经济波动   产出增长率   条件异方差   经济增长率   VAR模型   模型检验   交互影响   反应函数   利用结构   检验结果   发展规模   发展程度   政策调控  

摘要： 本文利用均值—条件异方差模型检验了我国产出增长率中的条件波动性(条件标准差)与经济增长速度之间的关系,并且利用结构VAR模型的冲击反应函数描述了增长率波动性和经济增长率水平之间交互影响的动态传导路径。检验结果表明,我国的经济波动性对经济增长水平具有正向的"溢出效应",体现出经济周期波动性与经济增长趋势之间的正相关性。由此说明,我国的金融发展程度和市场发展规模,以及宏观经济政策调控都具有一定程度的顺周期性质,特别是经济处于回升时期的经济政策方向与经济周期的扩张方向基本一致。我国经济周期波动性与经济增长趋势之间的正相关性预示着我国新出现的经济波动将是一轮上升型经济波动,未来一段时期的经济增长速度将在9%以上的水平上稳定地徘徊。

关键词： 合作建房   合同纠纷   表现形式   原因   土地使用权   房地产开发   中国  

摘要： 合作建房是改革开放后出现的一种新的经济合作形式。合作建房合同涉及诸多法律法规,且合同标的物价值大,情况十分复杂,加之目前与合作建房相关的法规不健全,合建合同纠纷呈上升趋势,其主要表现形式为合同主体不合格、当事人单方违约、未明确约定合建合同条款变更条件、出现投资亏损、支付土地使用权出让金、合建合同主要条款不明等情形。

关键词： 卫生检验实验室   计量认证   技术培训   产品质量   内部审核  

摘要： 计量认证是指省级以上人民政府计量行政部门对为社会提供公正数据的产品质量检验机构进行的计量检定、测试的能力和可靠性考核.

关键词： 检验科   临床科   结果准确性   互动作用   生理生化指标   标本质量   为病人服务   诊断和治疗   工作方式   检验报告   症状体征   检验人员   检验结果   诊断治疗   正确性   采集  

摘要： 临床科和检验科以不同的工作方式履行着为病人服务的共同目的。检验科通过检测病人各种各样的标本提供生理生化指标结果为临床诊断和治疗服务；临床科根据病人症状体征结合检验报告为病人明确诊断并进行治疗。各种各样的标本需要病人、护士、医生和检验人员互相协作采集，采集是否规范直接影响标本质量，标本质量又直接影响检验结果的准确性，准确性与诊断治疗的正确性密切相关；