RATIO SCALES AND CATEGORY SCALES OF ODOUR INTENSITY

The relation between a ratio scale obtained by magnitude estimationand a category scale of the odour intensity of 1-butanol wasstudied, together with individual variations in the ratio scale.Series of solutions of butanol in water in small bottles werepresented to a panel for judgement, half using the method ofmagnitude estimation, the other half a category scale. Plotswere made of the category scale against the ratio scale, andthe ratio scales of individual members of the panel were analysed.A power function exponent of 0.48 was found for the panel'sratio scale, with individual values ranging from 0.25 to 0.49.The category scale was curved relative to the ratio scale; variabilityof the magnitude estimates was approximately proportional tothe magnitude estimates; and a small time-order error was found.Odour intensity exhibits the three tested characteristics ofa prothetic continuum, and the variability of individual exponentswas not as great as sometimes suggested.     

EFFECTIVENESS OF CATEGORY AND LINE SCALES TO CHARACTERIZE CONSUMER PERCEPTION OF FRUITY FERMENTED FLAVOR IN PEANUTS

Fruity fermented (FF) flavor is a common off‐flavor in peanuts resulting from high‐temperature curing. The 9‐point hedonic scale is the most widely used scale to determine consumer acceptance; however, research has indicated that line scales may provide equal reliability and greater sensitivity. The objectives of this study were to characterize consumer perception of FF flavor in peanuts and to compare the effectiveness of the two scale types. Consumers (n = 208) evaluated control (no FF), low‐intensity (1.0) FF and high‐intensity (3.0) FF peanut pastes for the strength/intensity of roasted peanut flavor (RPF), sweet taste (ST), fresh peanut flavor (FPF) and overall liking (OV) using randomly assigned ballots. Sensitivity in defining consumer perception of off‐flavor in peanuts was greater with use of line scales than with the hedonic scale. The line scale indicated that FF flavor in peanuts, even at low intensity, negatively impacted OV and further identified significantly lower RPF and FPF perception by consumers. The hedonic scale identified only a difference in FPF and was not sensitive enough to show a difference in OV.     

USE AND ABUSES OF CATEGORY SCALES IN SENSORY MEASUREMENT

Category ratings are a popular device for assessing preferences and for guiding efforts in the development of new products. They are frequently misinterpreted or misused, however, because their use is so closely analogized to the process of fundamental measurement. Unlike physical measures, psychological scales such as category ratings are strongly affected by situational or contextual factors which must be carefully controlled and fully understood for proper use of the scale. Category ratings are affected by stimulus range and frequency, number of stimuli and number of categories, as well as by stimulus sequence. Implications for appropriate use of the scale in sensory evaluation are addressed.     

不同变性条件下肌酸激酶活力和构象变化的比较

以盐酸胍,十烷基硫酸钠和溴化十烷基三甲铵为变性剂,测定它们对肌酸激酶（ＣＫ）活力和构象之影响。结果发现：ＣＫ活力的丧失明显早于分子整体构象的变化;Ｃ１０Ｓ和Ｃ１０ＮＭ３对ＣＫ的变性有一定的饱和性;而ＧｕＨＣｌ对ＣＫ的变性则没有;溶液ＰＨ增加时,在一定范围内,ＧｕＨＣｌ,Ｃ１０Ｓ和Ｃ１０ＮＭ３对ＣＫ的变性能力都增加,在ＰＨ变化时,利用ＤＴＮＢ测定ＣＫ内埋巯基的暴露来反映构象的变化是成功的。     

A NEW APPROACH TO CATEGORY SCALES OF INTENSITY II: USE OF d'VALUES

Using a Rank-Rating method, d'values were obtained for stimuli from a model system using 15-point, 9-point, 7-point and 5-point category scales. For an apple/grape juice system, d'values were compared for 9-point and 7-point scales. There was general agreement on d'values among the scales, except where stimuli had their scores 'bunched'into one category: this tended to occur for the strongest and weakest stimuli for Rank-Rating and for the scales with fewer points. Bunching altered distribution variances and distorted the calculated d'values. Further study gave d'values for the discrimination of confusable stimuli, using paired-comparison and rating data, thus providing numerical measures of their relative sensitivity.     

COMPETITION BETWEEN A PROCHLOROPHYTE AND A CYANOBACTERIUM UNDER VARIOUS PHOSPHORUS REGIMES: COMPARISON WITH THE DROOP MODEL

The ecophysiology and competitive behavior of the prochlorophyte Prochlorothrix hollandica Burger-Wiersma, Stal et Mur, and the cyanobacterium Planktothrix agardhii Anagn. et Kom. were investigated in phosphorus-limited continuous cultures. When the species were exposed to successive saturating pulses of P, the maximal P uptake rate decreased linearly with an increase in the P cell quota. Prochlorothrix had a higher maximal P uptake rate, a lower half-saturation constant for P uptake, higher maximal cell quota for P, and slightly lower minimal cell quota for P than Planktothrix. These data indicate that Prochlorothrix is an affinity and storage strategist, at least when compared to Planktothrix. On the other hand, Prochlorothrix had a lower maximal growth rate than Planktothrix. On the basis of these ecophysiological parameters, we developed a Droop model to predict the time course and outcome of competition under various P regimes. The model predictions were in line with the results of competition experiments under three different P-limited conditions (continuous P supply, 4-day pulse period, 12-day pulse period). Prochlorothrix competitively displaced Planktothrix under both a constant and a pulsed P supply, and competitive displacement of Planktothrix was slowest in the experiment with a 12-day pulse period. In the pulsed experiments, the mean filament lengths and chl a fluorescence of the species oscillated at the same frequency as the pulse additions. In contrast to the Droop model, the predictions of the Monod model were not in line with the outcome of the competition experiments. Our results demonstrate that Prochlorothrix is a very good competitor for P and that the time course and outcome of competition for P in a variable environment can be predicted on the basis of the P uptake and storage characteristics of the species.     

A NEW APPROACH TO CATEGORY SCALES OF INTENSITY I: TRADITIONAL VERSUS RANK-RATING

A traditional approach to intensity scaling, using ratings on a 9-point category scale was compared to a method that combined elements of ranking called Rank-Rating. The latter method forced judges to retaste stimuli whose tastes they had forgotten and accordingly reduced discrimination errors, thus increasing ability to discriminate.     

COMPARISON OF RATING SCALES: SENSITIVITY, REPLICATES AND RELATIVE MEASUREMENT

The relative sensitivities of four scaling methods were assessed in central location tests with untrained judges. The scales included category scales, line scales, magnitude estimation, and a hybrid of the line and category scales. Approximate parity was observed among category scales, line scales and the hybrid scale in their ability to differentiate small physical differences. Magnitude estimation was used as efficiently as the other methods by a college population, but less efficiently by a heterogeneous sample of consumers. Judges used the scales with greater accuracy as they became familiar with the range of products to be judged. In spite of relatively small physical differences, subjects used wide ranges of the scales, supporting the view that rating scales are relative, not absolute, measuring instruments.     

COMPARISON OF 5-HYDROXYINDOLES IN VARIOUS REGIONS OF DOG BRAIN AND CEREBROSPINAL FLUID

Abstract— —Normal values for the concentration of 5-HT, 5-HIAA and tryptophan are established in various regions of the dog brain. After administration of tryptophan by intravenous injection the rise and fall of 5-HT and 5-HIAA were estimated at 1, 2 and 4 hr. Best fit quadratic regression curves obtained by computer programme were fitted to the data. Similar tryptophan doses were given to dogs and the 5-HIAA concentration estimated in the cisternal CSF. Quadratic regression curves fitted to these values show that the concentration of 5-HIAA in CSF reflects the changes of 5-HIAA in the brain and in particular in the brain stem. a-Methyl dopa pretreatment blocked the rise of 5-hydroxyindoles in brain and CSF and appeared to inhibit tryptophan hydroxylase as well as decarboxylase.     

COMPARISON OF GROWTH CHARACTERISTICS OF EXPERIMENTAL TUMOURS AND DERIVED CELL CULTURES

Cells from seven different rat tumours and a mouse sarcoma have been transplanted in syngeneic animals and were cultured in vitro. Tumours produced by inoculation of cultured cells in animals have been compared with the primary tumours. For the transplanted tumours, volume doubling times, T_d, have been compared with doubling times, T_d(cult), of cell numbers in cultures. Volume doubling times of the transplanted tumours generally decrease with increasing volume. At volumes of about 0.5 cm³, T_d values range from 2.2 days to 10 days, while T_d(cult) values ranged from 11 to 24 hr. A systematic correlation between T_d and T_d(cult) could not be established. During sequential transplantation of the tumours for many generations, as well as during continuous propagation of derived cell cultures, significant changes occurred which resulted in a decrease in the expression of differentiation characteristics in tumours.     

COMPARISON OF ATTRIBUTE LIKING AND JAR SCALES TO EVALUATE THE ADEQUACY OF SENSORY ATTRIBUTES OF MILK DESSERTS

Just-about-right (JAR) scales and attribute liking questions are usually used to study consumer perception of the sensory characteristics of food products. The aim of the present work was to compare the performance of attribute liking and JAR scales to evaluate consumers' perceived adequacy of flavor and texture of milk puddings. Two groups of consumers were asked to evaluate eight milk desserts using (1) overall liking followed by attribute liking for texture and flavor and (2) overall liking followed by JAR scales for thickness, creaminess, sweetness and vanilla flavor. Overall liking scores were significantly different when JAR scales or attribute liking questions were considered. Texture, flavor and overall liking scores were highly correlated to each other, providing the same information. JAR scales correlated better with the intensity of sensory attributes evaluated by a trained sensory panel, being JAR percentages a reliable tool to study the adequacy of sensory attributes.

PRACTICAL APPLICATIONS

Results from the present work showed that consumers might not be able to independently evaluate their liking of different sensory attributes of a product. For this reason, the use of attribute liking questions for studying the adequacy of sensory attributes in complex products would not be recommended. JAR scales were better indicators of the adequacy of sensory attributes. Consumers were able to independently evaluate texture and flavor attributes using JAR scales. However, the influence of JAR scales on overall liking scores should be taken into account when including these scales on consumer studies.     

GERMINATION AND GROWTH OF CELOSIA CRISTATA L., UNDER VARIOUS LIGHT AND TEMPERATURE REGIMES

Continuous light or alternating light and dark appear to be necessary for good germination of Celosia cristata L. As temperature increased up to 31 C so did germination; thereafter, it decreased. There appears to be a preference for high constant or high alternating temperatures in germination. As light intensity decreased so did growth in terms of leaf area, dry weight and relative growth rate. Proportionally more leaf is also made and leaf:area ratio increased. However, root weight ratio decreased. Although both high light intensity and high temperature are required for the good growth of Celosia, temperature appeared to be more important than light. A reduction of less than one-third of full light may not cause a significant reduction in growth. The results explain the observed differences in the nature of C. cristata in the field as well as its distributional limits.     

A GROWTH COMPARISON OF SPARTINA ALTERNIFLORA LOISEL. ECOPHENES UNDER AEROBIC AND ANAEROBIC CONDITIONS

Spartina alterniflora Loisel. culms were collected from tall (creekbank), short (highmarsh) and dieback sites in a North Carolina salt marsh and grown in aerobic and anaerobic simulated marsh systems in the greenhouse. There were no significant differences between density, aerial live biomass, height, leaf width or root biomass and sprig source. All variables were significantly different between aeration treatments. Aerated systems had an average of 6.3 times more biomass than the unaerated treatments. There was a significant interaction between sprig source and aeration treatments based on a multivariate analysis of variance representing overall plant performance. These results demonstrated that pioneer sprigs from the dieback sites had an advantage over the other sprigs when exposed to unaerated systems. Tall plants performed better than plants from short or dieback zones in the aerobic systems.