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Ability of dogs to discriminate human odor exposed to chemical detergent
Čajágiová, Martina ; Vyplelová, Petra (advisor) ; Jaroslav, Jaroslav (referee)
In the recherche part of our thesis we familiarize ourselves with the human odor, theories of its origin, definition, anatomy of human skin and odors, composition of individual human odors and with odor secretion. We also look closer on the topics of odor absorbent and its use in the world, the transmission of odors to odor sensors and securing of scents. This section of our thesis discusses the resistance and survival abilities of odor, scent identification method and its history, organic acids, and defines the application of laundry detergents and ultrasonic washers. Aim of our thesis was to verify the relevance of the use of chemical detergents in the purification process when working with scents. We tried to verify the ability of detergents to degrade the human scent on odor absorbents to such an extent, that specially trained dogs would not be able to identify it. Our experiment was following a precise determination methodology. In the first phase samples were collected from the hands of targeted persons to a scent carrier - a metal cylinder (extirpate odour), by one researcher. In the second phase samples were collected from the body to a textile carrier, by another researcher. The metal scent carriers were processed. Some of them were left as they were (control sample) and some were exposed to chemical detergents with and without usage of an ultrasonic washer.
In the experiment where we tried to identify the odour samples, six bitches of German shepherd were used. They were specially trained for odour identification. Each dog was let three times to identify the target scent exposed to a detergent and three times to identify the target scent not exposed to a detergent. Target smell was randomly deposited between other samples and its position was changed, so that the handler did not know its position and thus was unable to affect the work of his dog. The indicator of positive identification was a sign the dogs were taught - to sit or lay in front of a sample.
Any dog was unable to identify the scent which was exposed to chemical detergent and all dogs identify the scent unexposed to a chemical detergent. Our experiment has shown that the use of chemical detergents in the purification process when working with scents is relevant to the degradation of individual human scent.
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Ability of specially trained dogs to detect human scent which was exposed to different weather conditions over a long period
Machová, Lucie ; Vyplelová, Petra (advisor) ; Jaroslav, Jaroslav (referee)
Survivability of human scent was observed by many scientists mainly in artificial conditions (Hudson et al., 2009; Santariová et al. 2012; Preti et al., 2006). Against this exists a few researches about survivability of human scent in nature conditions (King et al., 1964; Santariová et al., 2016).
On glass tubes were taken individual humant scent from 6 volunteers. Target scents were left outdoor during 2 different periods of year. Winter samples from 3 target people were outdoor from November to May and summer samples from other 3 people from May to December. Always after 3, 4, 5 a 6 months was taken scent from 1 glass tube of each target person. After last time period was taken scent from target people on cotton textile. Scent of other volunteer was taken at the same time for purpose scent deceptions.
Then was observed if dogs will be able to identify these samples corectly. Specially trained dogs on scent identification line-ups get sample from outdoor environment and they should choose the identical human scent from line of 6 samples (with 1 target and 5 deceptions).
The experiment showed, that dogs are able to identify winter samples in all time periods but are not able to identify summer samples in whatever time period. Time periods do not show any diference.
The biggest influence on quality change of individual human scent has intensity of sun radiation.
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