Sensation methods

Meillon, S., Urbano, C. and Schhch, P. (2009). Contribution of the temporal dominance of sensations method to the sensory description of subtle differences in partially dealcohohzed red wines. Food Quality and Preference, 20, 490-499. 

Detection. Many people can detect hydrogen cyanide by odor or taste sensation at the 1 ppm concentration in air, most at 5 ppm, but HCN does not have an offensive odor and a few people cannot smell it even at toxic levels. Anyone planning to work with hydrogen cyanide should be checked with a sniff test employing a known safe concentration. This test should be given periodically. Several chemical detection and warning methods can be employed. The most rehable are modem, electronic monitors based on electrolytes that react with hydrogen cyanide. 

ISO EN 7730 standardizes the PMV-PPD index as the method for evaluation of moderate thermal environments. To quantify the degree of comfort, the PMV (predicted mean vote) index gives a value on a 7-point thermal sensation scale -t-3 hot, +2 warm, +1 slightly warm, 0 neutral, -I slightly cool, -2 cool, -3 cold. An equation in the standard calculates the PMV index based on the six factors (clothing, activity, air and mean radiant temperatures, air speed, and humidity). 

Basically, there are four major types of measures that are used in taste intensity measurements (a) threshold measures or estimates of the physical level at which the sensation of sweetness begins, (b) equal-sweetness matches between a sugar and other sweeteners, (c) category or rating scales, and (d) ratio scales. Each method has found its adherents and uses, and each possesses specific advantages and defects that indicate its use for one application, but contraindicate its use for another. These methods and their applications have been critically analyzed and reviewed, " " and it is, therefore, superfluous to deal with the topic here. 

Obviously this procedure involves a lengthy and complex follow-up to the original analysis. Furthermore it is important to note that although the analytical results are objective measurements, the appraisal of their effectiveness in describing the emission, ultimately relies on subjective comparisons of odour sensation. This final observation could be interpreted as a weakness in the method in having to resort to subjective odour comparisons. An alternative viewpoint however is that the most effective information can be derived by utilising a combination of olfactometric and physico-chemical techniques. 

In a population-based study, hallucinations had occurred in 16% and delusions in 5% of PD patients during the month prior to evaluation. These symptoms were more common in those with dementia (Aarsland, 1999a). In a recent study using more detailed assessment methods and also including minor forms consisting of a sensation of presence, a sideway passage or illusions, 40%... 

Sensibility The ability to receive, feel and appreciate sensations and impressions the quahty of being sensitive the extend to which a method gives results that are free from false negatives, [nih]... 

His work-day includes in part the collation of notes on laboratory experiments and these tasks are carried on until around six in the evening. His laboratory [or studio] should be well ventilated but, above all, darkened. At least one portion of it will remain in complete darkness. In practise certain operations are improved by being performed when protected from light.. . . These operations are always done by him with complete propriety and in perfect order. His exercises shall be conducted with method, either according to the meaning of the texts consulted or following one s personal inspiration.. . . [Duchamp] shall instigate poetic reflections and artistic sensations. . . For these purposes, nocturnal tranquility is especially recommended. After dinner, and after consumption of tobacco, he resolutely sets about the extended work of composition, that is, should he perform as a hermetiste ecrivain. 

Assessment of taste is achieved by sensory analysis, from very simple experiments such as triangular tests aiming at determining detection thresholds to complex descriptive analysis approaches. A method referred to as time-intensity that consists in recording continuously the intensity of a given sensation over time under standardized conditions has been applied to study flavonoid bitterness and astringency properties. 

While some researchers feel that individual components making up the sensory response need to be characterized (9), others feel that methods dealing with the composite sensation are more appropriate. For this reason methods which do not rely on internal representation of terms have been applied. One such method is multidimensional scaling (MBS), which treats data based on a persons total perception of the dissimilarity between objects.(10)... 

Since the effect they produce is actually an irritation to the nerve endings responsible for heat and pain sensation in the mouth, standardization of the level of heat is essential. Methods for their analysis include organoleptic and spectrophotometric methods. Historically the organoleptic one has been preferred by the food industry since it is a direct measure of levels of heat. Nowadays a variety of GC (after derivatization) and HPLC with UV or fluorescence detection methods have been proposed. 

The direct transformation from the output pattern to the taste quality was performed here as one trial of expressing the actual human sensation using the output electrical pattern. A similar trial was done for evaluation of the strengths of sourness and saltiness, which will be mentioned later. These two trials depend on the utilization of simple transformation equations by extracting typical properties of output patterns. This method is effective if some data on sensory tests, using humans as a standard, can be obtained to compare with the sensor outputs. However, the expressions for the tastes of beer are obscure because they are not described by the five basic taste qualities. The purpose of the application of the taste sensor is also to express these kinds of obscure terms of human sense in scientific terms. 

Too little oil and the product tastes flat and lacks character too much and the product gives the mouth a burning terpen-like sensation. United States Standards for Grades of citrus juices regard too much oil as a defect in manufacturing. The official method for the determination of recoverable oil is the Scott Method (8). 

In order to reproduce the color sensation of an observer, we could reproduce exactly the same spectral characteristic for every point of the image. This sensation would be indistinguishable from the original sensation. However, we do not usually have a spectrometer to measure the entire spectrum for every image point, let alone a method to create a color spectrum given such measurements. However, quite a large number of colors can be reproduced using only three color primaries. 

The colorant varies, from one preparation to another, in its degree of dispersion, as demonstrated by the amounts that can be removed from solutions by various filtration or defecation techniques. In the case of the colorant associated with raw sugars, the degree of dispersion varies with the method of preparing the solution. This suggests that the impurities causing the twin, visual sensations of color and turbidity are closely related, and may, in fact, be the same materials. 

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