共查询到20条相似文献,搜索用时 15 毫秒
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CHRISTINE H. SCAMAN J. DOU MARGARET A. CLIFF DOGAN YUKSEL MARJORIE C. KING 《Journal of sensory studies》2001,16(3):287-300
Principal component similarity (PCS) analysis was used to evaluate judge performance from a wine competition. Data were analyzed for five international judges and seven wine makers, for 42 white, 30 red and 25 specialty wines, using a 20-point quality scoring system. Principal similarity plots were used to group judges according to judging 'style' and to identify outliers, for each wine category. Judge groupings were consistent when three different references were used; however, the most interpretable PCS plot was obtained when the overall mean-judge-score was used as the reference. Results from PCS were compared to principal component analysis (PCA). PCS analysis allowed the information from all significant principal components to be graphically represented in two dimensions and was more successful in classifying judges than plots based on the first three principal components. The technique of PCS is an important complement to existing methodologies, and can provide wine competition coordinators with an objective technique for judge evaluation and selection. 相似文献
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Judges on anti-nausea medication, used hedonic scales to assess a set of foods and beverages on two occasions, initially on beginning a treatment with anti-nausea medication and then four weeks later. To detect the possibility that changes in hedonic scores for the foods and beverages may be caused not by changes in liking but by 'scaling drift': changes in the use of the scale, control stimuli were also assessed. These control stimuli were sets of stimuli to be assessed for intensity and a set to be assessed for liking. These latter stimuli were a class of stimuli that were unlikely to be liked to a different extent on the two testing occasions. The lack of change in the control stimuli and the change in the hedonic scores for the foods and beverages suggested that the latter was due to changes in liking for the foods and beverages rather than 'scaling drift'. 相似文献
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A collaborative study of twenty-three laboratories was conducted to compare the relative effectiveness of three scales: two forms of magnitude estimation scaling and one form of a category scale in the measurement of hedonic response to a controlled stimulus. Responses from 553 individual judges show that all scales yield hedonic measurements that are very similar in both direction and magnitude of difference between the stimuli. No scale showed any clear superiority in reliability, precision, or discrimination. Selection of a scale must be based on considerations other than the simple form of response. 相似文献
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Single product scaling and relative-to-reference scaling were compared on the basis of numbers of significant differences among chocolate milks and among vanilla yogurts using both trained and untrained panels. The study involved 920 comparisons among product means with appearance, flavor and mouthfeel attributes. Although there were a greater number of significant t-tests when the relative-to-reference scales were used by both trained and untrained panels, the differences between scale types were minor. Panels showed no advantage with the type of scale they used first. The two methods may be used with equal efficiency for sensory evaluations. 相似文献
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This study examined the contributions of stimulus fat content and flavor volatiles to the perception of fat in a milk model system. The model system was formulated by adding bland vegetable oil (0%, 5%, or 10% w/v) and natural cream flavor (0%, 0.5% or 1% w/v) to a skim milk base. Panelists judged pairs of samples for similarity on the basis of three attributes (fat content, mouthcoating and thickness) and the results were analyzed using a multidimensional scaling procedure. Two-dimensional solutions best represented the data. The stimulus spaces for fat content and mouthcoating were visually similar to each other and provided reasonable separation of the samples. Instrumental measures helped to define the underlying dimensions of the stimulus space for fat content. Dimension 1 related to texture and included the contributions of viscosity, and fat particle size and number distribution; dimension 2 related to flavor perception. The sample with a moderate fat content (5%) and the highest concentration of added cream flavor (1%) was perceived to be similar to the 10% fat samples with added flavor. Thus, the added flavor provided the sensation of higher fat content. These data suggest that flavor plays an important role in the preception of fat in dairy foods. A psychophysical model of fat perception in dairy foods is proposed which includes the contribution of viscosity, fat particle size and number distribution, and volatile flavor perceptions. 相似文献
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Microscopic dust sampling was done to determine the amount of dust in the homes of six patients who were sensitive to house dust and who had allergic disease that was intractable to treatment. One case was subsequently excluded from the study because of extraordinary circumstances. The remaining five cases were studied with repeated dust counts before and after a water-and-oil emulsion was sprayed in the patient''s bedroom to immobilize house dust. In all five cases, the patients had dramatic relief of symptoms after the spraying was done. In four out of five, there was concomitant reduction of the amount of dust in the air as determined by microscopic counting of the dust particles on a glycerincoated slide. In the fifth case, relief of symptoms was not accompanied by reduction of dust on slides, but investigation revealed an error in control of exposure of the slides. 相似文献
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Wine vinegar is a product obtained from wine acidification which contains at least 5% by wt. of acetic acid, in general without any additives or colorings.
Aspects studied in this work include: the determination of the taste group thresholds (geometric mean of the individual best-estimate thresholds "BET") of two different acids (citric and acetic acids) in aqueous solution and spanish vinegars produced from table and sherry wines. The results obtained suggest that wine vinegar can be considered something more than just an acidulant agent.
In order to evaluate differences among wine vinegars, discriminant tests for twenty-five spanish vinegars (sherry, table and flavored vinegars) were applied. Six of the twelve attributes freely chosen by assessors allowed grouping of the spanish wine vinegars according to their sensory aspects. 相似文献
Aspects studied in this work include: the determination of the taste group thresholds (geometric mean of the individual best-estimate thresholds "BET") of two different acids (citric and acetic acids) in aqueous solution and spanish vinegars produced from table and sherry wines. The results obtained suggest that wine vinegar can be considered something more than just an acidulant agent.
In order to evaluate differences among wine vinegars, discriminant tests for twenty-five spanish vinegars (sherry, table and flavored vinegars) were applied. Six of the twelve attributes freely chosen by assessors allowed grouping of the spanish wine vinegars according to their sensory aspects. 相似文献
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中药黄芩类的品质评价及资源利用 总被引:12,自引:0,他引:12
用薄层光密度法测定37种黄芩12个省区的59个样品中黄芩甙(baicalin)(Ⅰ)和汉黄芩甙(wogonoside)(Ⅱ)的含量,同时还测定了甘肃黄芩中特有的主要成分甘肃黄芩甙元(gannuangenin)(Ⅲ)的含量。根据分析结果,对中药黄芩类的质量进行了评价,对资源利用前景提出了参考意见。 相似文献
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F. James Rohlf Michael C. Wooten 《Evolution; international journal of organic evolution》1988,42(3):581-595
Comparisons are made of the accuracy of the restricted maximum-likelihood, Wagner parsimony, and UPGMA (unweighted pair-group method using arithmetic averages) clustering methods to estimate phylogenetic trees. Data matrices were generated by constructing simulated stochastic evolution in a multidimensional gene-frequency space using a simple genetic-drift model (Brownian-motion, random-walk) with constant rates of divergence in all lineages. Ten differentphylogenetic tree topologies of 20 operational taxonomic units (OTU's), representing a range of tree shapes, were used. Felsenstein's restricted maximum-likelihood method, Wagner parsimony, and UPGMA clustering were used to construct trees from the resulting data matrices. The computations for the restricted maximum-likelihood method were performed on a Cray-1 supercomputer since the required calculations (especially when optimized for the vector hardware) are performed substantially faster than on more conventional computing systems. The overall level of accuracy of tree reconstruction depends on the topology of the true phylogenetic tree. The UPGMA clustering method, especially when genetic-distance coefficients are used, gives the most accurate estimates of the true phylogeny (for our model with constant evolutionary rates). For large numbers of loci, all methods give similar results, but trends in the results imply that the restricted maximum-likelihood method would produce the most accurate trees if sample sizes were large enough. 相似文献
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Teeth of known-age Cape fur seals Arctocephalus pusillus pusillus were used to validate age estimated from ground sections. In the canines, dentine growth layer groups (GLGs) reflected age accurately but no reliable readings could be obtained from GLGs in the cementum. Upper canines were the most suitable for age estimation. By contrast, in the postcanines where the cementum is thicker, only GLGs in the cementum could be used for age determination, but not with the same accuracy as for dentine in the canines. Therefore, it is recommended that GLGs in the dentine be used to determine age in the Cape fur seal. However, pulp cavities in canines closed at about 13 yr and consequently GLGs in the cementum of the postcanines should be used where the pulp cavities of canines are closed. Accurate estimation of age is not possible from the dentine of older animals. 相似文献
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SUMMARY: Different suspensions of Bacterium coli in distilled water, prepared by a routine technique and adjusted nephelometrically with reference to a ground glass screen, showed no significant difference in their viable counts at the 5% level.
In a study of the inhibition by phenol of cultures grown in peptone water from inocula of such suspensions the regression line obtained by plotting the probit of the percentage inhibition against the logarithm of the concentration was rectilinear. From this the concentration needed for 95% inhibition was calculated. 相似文献
In a study of the inhibition by phenol of cultures grown in peptone water from inocula of such suspensions the regression line obtained by plotting the probit of the percentage inhibition against the logarithm of the concentration was rectilinear. From this the concentration needed for 95% inhibition was calculated. 相似文献
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利用PEG法建立药用真菌灵芝的转化系统 总被引:10,自引:1,他引:9
本文首次建立了一种通过PEG转化缓冲液将外源基因转入灵芝的方法,转化频率约为5~6个/mg(抗性转化子/质粒+107个原生质体)。转化子在不含HmB的培养基上经5代以上的继代培养后仍可以稳定表达HmB抗性。Southernblot检测证明外源基因已经整合到了灵芝的基因组DNA中。本研究为通过基因工程手段定向、快速改良灵芝药用品质以及利用灵芝发酵方法生产一些具有重大经济价值的外源蛋白等应用奠定基础,并且也有助于我们进一步了解灵芝这一大型真菌中的基因的表达调控机制。 相似文献
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Multidimensional scalings of odor similarities in two conditionswere examined, with 7 odors, 15 subjects, and scaling in Euclideanspace with individual differences taken out as a third mode,by INDSCAL. It was shown that the presence of additional odorword profiles as dummy stimuli modified the relations betweenodors, thus attenuating the generality of verbally-based odorscaling methods. 相似文献