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关键词： model accuracy   sample survey   study design   classification trees   lichens   accuracy assessment   probability samples   non-probability samples  

摘要： We evaluated the effects of probabilistic (hereafter DESIGN) and non-probabilistic (PURPOSIVE) sample surveys on resultant classification tree models for predicting the presence of four lichen species in the Pacific Northwest, USA. Models derived from both survey forms were assessed using an independent data set (EVALUATION). Measures of accuracy as gauged by resubstitution rates were similar for each lichen species irrespective of the underlying sample survey form. Cross-validation estimates of prediction accuracies were lower than resubstitution accuracies for all species and both design types, and in all cases were closer to the true prediction accuracies based on the EVALUATION data set. We argue that greater emphasis should be placed on calculating and reporting cross-validation accuracy rates rather than simple resubstitution accuracy rates. Evaluation of the DESIGN and PURPOSIVE tree models on the EVALUATION data set shows significantly lower prediction accuracy for the PURPOSIVE tree models relative to the DESIGN models, indicating that non-probabilistic sample surveys may generate models with limited predictive capability. These differences were consistent across all four lichen species, with 11 of the 12 possible species and sample survey type comparisons having significantly lower accuracy rates. Some differences in accuracy were as large as 50%. The classification tree structures also differed considerably both among and within the modelled species, depending on the sample survey form. Overlap in the predictor variables selected by the DESIGN and PURPOSIVE tree models ranged from only 20% to 38%, indicating the classification trees fit the two evaluated survey forms on different sets of predictor variables. The magnitude of these differences in predictor variables throws doubt on ecological interpretation derived from prediction models based on non-probabilistic sample surveys. (c) 2006 Elsevier B.V. All rights reserved.

关键词： outcome   psychosis   mania   Brief Psychiatric Rating Scale   first episode  

摘要： Research on predicting and preventing episodes of schizophrenia and mood disorder lacks consistent, specific definitions of episodes. We present an operational system for identifying relapse, exacerbation, and remission of schizophrenia and bipolar disorder within longitudinal studies that involve repeated symptom assessments. Three major classes of episodic outcome are defined: relapse or significant exacerbation, nonrelapse, and stable, severe persisting symptoms. These major classes are further subdivided to distinguish nine categories of episodic outcome. To examine ease of use, interrater reliability, and validity, the classification system was applied to recent-onset samples of schizophrenia patients (N=77) and bipolar mood disorder patients (N=23) followed on medication for 9- to 12-month periods. A range of episodic outcomes were distinguished with high interrater reliability. Despite being prescribed continuous medication, 21% of the recent-onset schizophrenia patients and 61% of bipolar patients met criteria for relapse or significant exacerbation during this follow-up period. Predictive relationships support the validity of this system for classifying episodes. A computer program is available to facilitate its use. Use of these explicit definitions of episodes may help to clarify the relationship between episodic outcome and other fundamental domains of illness outcome, particularly other symptom dimensions, work functioning, and social functioning. (c) 2005 Elsevier Ireland Ltd. All rights reserved.

关键词： 标本   涂片   革兰染色  

摘要： 标本直接涂片革兰染色有助于正确鉴别标本来源和性质,判断机体某些系统的微生态是否平衡,有助于对感染菌的判断,有助于提高标本阳性检出率,有助于临床早诊断,早治疗。总之,可以为临床提供科学的诊疗依据。

关键词： OLIGOMERS   ALICYCLIC compounds   BICYCLIC compounds   VOLTAMMETRY   ATOMIC absorption spectroscopy  

摘要： Previous studies of the redox states of linear conjugated oligomers as models for polarons and bipolarons in conjugated polymers do not fully address the influence of intermolecular interactions on the electronic structure of conjugated systems in the solid state. Fusion of oligothiophenes onto a bicyclo[4.4.1]undecane core holds the conjugated oligomers in a permanent cofacial stack. One- and two-electron oxidation of the stacked oligomers affords mono(radical cation)s and dications that serve as models for polarons and bipolarons in p-doped conjugated polymers and demonstrates the effect of π-stacking on the electronic structure of these species.

关键词： PARTNERSHIP (Business)   FERMENTATION   INDUSTRIAL microbiology   INVESTMENTS   RESEARCH & development   BACTERIA  

摘要： Tate & Lyle and Microbia Precision Engineering(MPE)are expected to announcethis week the formation of a five-year partnership to develop fermentation-derived ingredients forfood and industrial ***-based Tate & Lyle is one of the world's major producers offermentation-based chemicals and other ingredients.

关键词： 型式检验   《电动自行车通用技术条件》   质量管理   生产许可证   生产条件   企业   助力车   定期   产品  

摘要： 助力车产品生产许可证企业生产条件审查办法中规定：企业应定期依据国标、行标或企标对产品定期进行型式检验，按照目前GB17761-1999《电动自行车通用技术条件》中规定：年产万辆以下，每六个月进行一次；年产万辆以上，每三个月进行一次，但是从目前所了解的情况看，对这一规定执行得并不尽人意，可能有的是怕麻烦，也有的是为减少眼前看得见的成本支出，可能更多的是企业对型式检验的作用不是太清楚，为此，必要提醒企业重视这一问题。

关键词： amphotericin B   solid state NMR   REDOR   phospholipid   lipid bilayer  

摘要： The membrane interaction of amphotericin B (AmB), one of the most important anti-fungal drugs, was investigated by solid state NMR measurements of uniformly C-13-enriched AmB, which was prepared by the culture of the drug-producing microorganism in the presence of [u-C-13(6)]glucose. All the C-13 NMR signals of AmB upon binding to DLPC membrane were successfully assigned on the basis of the C-13-C-13 correlation spectrum. C-13-P-31 RDX (Rotational-Echo Double Resonance for X-clusters) experiments clearly revealed the REDOR dephasing effects for carbon atoms residing in the both terminal parts, whereas no dephasing was observed for the middle parts including polyolefinic C20-C33 and hydroxyl-bearing C8/C9 parts. These observations suggest that AmB binds to DLPC membrane with a high affinity to the phospholipid and spans the membrane with a single molecular length. (c) 2006 Elsevier Ltd. All rights reserved.

关键词： 违约责任   侵权责任   涉外违约责任与侵权责任竟合  

摘要： 随着国际经贸交往的发展,涉外违约责任与侵权责任竞合的现象大量涌现,而大多数国家的涉外法律均未对此类案件的处理作出明确规定。此类案件的处理已成为国际私法领域的一个新课题。本文拟对此类案件的一般处理方法、特殊处理方法和法律规避问题进行探讨,以期能为此类案件的解决提供些许参考。

关键词： Proteins   Lipids   Mutagenesis   Shock   Membranes  

摘要： The mechanosensitive channel of small conductance (MscS) is a bacterial mechanosensitive channel that opens in response to rapid hypoosmotic stress. Since MscS can be opened solely by membrane stretch without help from any accessory protein, the lipid-protein interface must play a crucial role in sensing membrane tension. In this study, the hydrophobic residues in the lipid-protein interface were substituted one by one with a hydrophilic amino acid, asparagine, to modify the interaction between the protein and the lipid. Function of the mutant MscSs was examined by patch-clamp and hypoosmotic shock experiments. An increase in the gating threshold and a decrease in the viability on hypoosmotic shock were observed when the hydrophobic residues near either end of the first or the second transmembrane helix (TM1 or TM2) were replaced with asparagine. This observation indicates that the lipid-protein interaction at the ends of both helices (TM1 and TM2) is essential to MscS function.

关键词： atherosclerosis   infrared attenuated total reflection catheter   multivariate classification   chemometrics   resubstitution   bootstrap resampling  

摘要： The strongly overlapping infrared absorption features of atherosclerotic and normal rabbit aorta samples as governed by their water, lipid, and protein content render the direct evaluation of molecular characteristics obtained from infrared (IR) spectroscopic measurements challenging for classification. We have successfully applied multivariate data analysis and classification techniques based on partial least squares regression (PLS), linear discriminant analysis (LDA), and principal component regression (PCR) to IR spectroscopic data obtained by using a recently developed infrared attenuated total reflectance (IR-ATR) catheter prototype for future in vivo diagnostic applications. Training data were collected ex vivo from atherosclerotic and normal rabbit aorta samples. The successful classification results on atherosclerotic and normal aorta samples utilizing the developed data evaluation routines reveals the potential of spectroscopy combined with multivariate classification strategies for the identification of normal and atherosclerotic aorta tissue for in vitro and, in the future, in vivo applications.