• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 141
  • 65
  • 48
  • 14
  • 10
  • 10
  • 9
  • 7
  • 7
  • 7
  • 7
  • 7
  • 7
  • 2
  • 2
  • Tagged with
  • 371
  • 71
  • 52
  • 36
  • 28
  • 27
  • 25
  • 24
  • 23
  • 22
  • 19
  • 19
  • 18
  • 18
  • 18
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Lateralization of human olfaction : cognitive functions and electrophysiology

Broman, Daniel January 2006 (has links)
<p>In this thesis lateralization of olfactory functions was investigated by both behavioral and electrophysiological assessment, the latter with the olfactory event-related potential (OERP) technique. The olfactory sense is primarily ipsilateral in that a stimulus that is presented to one nostril is initially processed in the same hemisphere. This makes it possible to observe differences between stimulated nostrils as an indication of hemispheric difference. Study I explored differences in olfactory cognitive functions with respect to side of rhinal stimulation and demonstrated that familiarity ratings are higher at right- compared to left-nostril stimulation. No differences were found in episodic recognition memory or free identification, possibly reflecting inter-hemispheric interactions in higher cognitive functions. Effects of repetition priming were present in odor identification and tended to be more pronounced when tested via left nostril. Study II further investigated the effect of previous exposure in odor identification by a different experimental set-up, and demonstrated effects of repetition priming when tested via left- but not right-nostril stimulation. This finding indicates the importance of reconsidering possible sequential effects in olfactory research. Study III examined methodological aspects of an OERP protocol with respect to stimulus duration, which was used in Study IV. No differences in amplitudes or latencies where found between the stimulus durations of 150, 200 and 250 ms, suggesting the commonly used duration of 200 ms in a standard protocol. Study IV investigated laterality effects in OERPs with respect to side of stimulation and electrode site. The results showed consistent amplitudes and latencies regardless of rhinal side of stimulation. Larger amplitudes were demonstrated on left hemisphere and midline compared to right hemisphere, possibly explained by smaller N1/P2 amplitudes at the right-hemisphere sites at left-nostril stimulation. Apart from a proposed OERP protocol, the findings support the notions of a right-hemisphere predominance in processes related to olfactory perception and indicate, in accordance with other findings, a left-side advantage in conceptual repetition priming.</p>
72

Lateralization of human olfaction : cognitive functions and electrophysiology

Broman, Daniel January 2006 (has links)
In this thesis lateralization of olfactory functions was investigated by both behavioral and electrophysiological assessment, the latter with the olfactory event-related potential (OERP) technique. The olfactory sense is primarily ipsilateral in that a stimulus that is presented to one nostril is initially processed in the same hemisphere. This makes it possible to observe differences between stimulated nostrils as an indication of hemispheric difference. Study I explored differences in olfactory cognitive functions with respect to side of rhinal stimulation and demonstrated that familiarity ratings are higher at right- compared to left-nostril stimulation. No differences were found in episodic recognition memory or free identification, possibly reflecting inter-hemispheric interactions in higher cognitive functions. Effects of repetition priming were present in odor identification and tended to be more pronounced when tested via left nostril. Study II further investigated the effect of previous exposure in odor identification by a different experimental set-up, and demonstrated effects of repetition priming when tested via left- but not right-nostril stimulation. This finding indicates the importance of reconsidering possible sequential effects in olfactory research. Study III examined methodological aspects of an OERP protocol with respect to stimulus duration, which was used in Study IV. No differences in amplitudes or latencies where found between the stimulus durations of 150, 200 and 250 ms, suggesting the commonly used duration of 200 ms in a standard protocol. Study IV investigated laterality effects in OERPs with respect to side of stimulation and electrode site. The results showed consistent amplitudes and latencies regardless of rhinal side of stimulation. Larger amplitudes were demonstrated on left hemisphere and midline compared to right hemisphere, possibly explained by smaller N1/P2 amplitudes at the right-hemisphere sites at left-nostril stimulation. Apart from a proposed OERP protocol, the findings support the notions of a right-hemisphere predominance in processes related to olfactory perception and indicate, in accordance with other findings, a left-side advantage in conceptual repetition priming.
73

Ozone deodoration of wasted gases from rubber processing

Cheng, Li-Yi 01 July 2008 (has links)
This study was aimed at the removal of odorous compounds in gases emitted from rubber processing industries. Odorous gas for test was prepared by mixing fresh air and an odorous gas drawn from an oven in which a sample of rubber powder was kept at 160 and 200 oC, respectively. For ozonation tests, the prepared odorous gas was then premixed with a definite amount of ozone-enriched air before entering into a contact system. The contact system consists of two sieve-plate columns connected in series and each column has four 1-L chambers. Depending on with or without introducing a circulating scrubbing water into the columns, the oxidation reaction could be either wet or dry one. For UV/ozonation (UV/O3) tests, batch reactions were performed in a 3.63-L chamber fitted with an UV lamp inserted in a quartz column. A definite volume of the odorous gas generated from the oven was injected into the chamber containing a definite concentration of ozone. Results from the dry-ozonation tests indicate that that 82 and 70% of VOCs and odorous intensity in the influent gas could be removed, respectively, with the operation conditions of an initial ozone concentration of 4.0 ppm, VOC (methane equivalent) concentrations of 6.5-9.0 ppm, an oxidation temperature of 38.5 oC, and a gas empty-bed-retention time (EBRT) of 8.6 s. Both the VOC and odorous intensity removal efficiencies were roughly proportional to the EBRT in the range of 1.4-11.4 s. Wet-ozonation got 97 and over 90% of VOC and odorous intensity removal, respectively, with the operation conditions of initial ozone concentration 4.0 ppm, VOC (methane equivalent) concentrations 6.5-10.3 ppm, oxidation temperature 37.3 oC, gas EBRT 12 s, and liquid/gas rate ratio 0.01 m3/m3. With conditions similar to those cited above, odor concentration (dilutions to the threshold) in the test gas could be removed from 3,090 to 130 with an EBRT of 14.5 s. Tests also indicate that activated carbon is effective for both physical and chemical removals of the residual VOCs, odorous compounds, and ozone in the effluent gas from the ozonation system. Economical analysis indicates that around NT$ 5.4 is required for treating 1,000 m3 of the tested foul gas by the proposed wet-ozonation and activated carbon adsorption process. Odor concentration (dilutions to the threshold) in a test could be reduced from around 4,000 to 70. Results of UV/O3 tests indicate that the introduction of the 185 nm UV irradiation at the intensity of 5W/3.63L did not help in the additional VOC and odor removals with an initial ozone concentration 4.0 ppm, VOC (methane equivalent) concentrations of 12.2-15.0 ppm, oxidation temperature of 31.5 oC, and reaction time 18.2 s. UV irradiation is not necessary for the ozonation odor removal of the test gas samples.
74

Storage stability of freeze dried raspberry and blackberry juices

Patton, Kathleen A. January 1986 (has links)
No description available.
75

Simulation of odour dispersion around natural windbreaks

Lin, Xing Jun, 1960- January 2006 (has links)
The research objective was to calibrate a model to simulate odour dispersion downwind from natural windbreaks and then, use this model to observe the effect of windbreak characteristics and climatic conditions on the size of the odour dispersion plume. Computational fluid dynamic (CFD) models were used for the simulations because of their capability in reproducing turbulent wind conditions. The model was initially calibrated to ensure the proper velocity recovery ratio (VRR), and then to reproduce odour plumes measured in the field by three groups of four panellists. / The visual and statistical analysis of the field panellist observations indicated that a windbreak with an optical porosity of 0.35 could reduce by 21% the length of the odour dispersion plume, as compared to a site without a windbreak. Also, these analyses indicated that the site with a windbreak offering an optical porosity of 0.55 had no significant impact on the length of the odour plume, as compared to the site without a windbreak. / The models selected for the simulations were the Fluent 6.2 standard k-epsilon and SST k-o models. Their odour dispersion calibration indicated that both models can accurately reproduce the field measured odour hedonic tone and odour concentration by transforming the odour mass fraction computed by the models into the hedonic tone with a power function, and then into the odour concentration with an exponential function. The correlations between the simulated and measured absolute HT and between the simulated and measured odour concentrations were statistically significant (P < 0.01). However, the SST k-o was preferred over the standard k-epsilon because it could physically better reproduce the high turbulence conditions created by the windbreak. / The SST k-o model simulations indicated that odour plume length was mostly affected by windbreak porosity and height, as well as distance from the source. In terms of climatic conditions, odour plume size was mostly affected for atmospheric stability conditions which generally established ambient wind speed and rate of change of temperature. Wind direction has an impact on the length of the odour plume and the formation of a fin intensifying odour concentration near the windbreak, where an angle of 45º produces the shortest odour plume and the largest fin. / Key words: Simulation; odour; dispersion; natural Windbreak; CFD.
76

Kvapų poveikio aplinkai valdymas / Odor impacts effects enviromental management

Volodko, Jolanta 03 June 2014 (has links)
Darbe yra pristatytos sąvokos, susijusios su kvapais, aptariami kvapų susidarymo šaltiniai. Nagrinėjimas kenksmingų kvapų poveikis aplinkai ir žmogaus sveikatai, analizuojami nemalonių ir pavojingų kvapų šalinimo būdai ir nauji metodai, aptariamos prevencinės priemonės. Taip pat analizuojamos sąveikos tarp aplinkos, aiškinamos kvapų aptikimo technologijos, matavimo būdai. Nagrinėjama institucijų, dalyvaujančių kvapų valdyme funkcijos ir atsakomybę, nagrinėjimas ekspertų interviu dėl kvapų valdymo ir kontrolės proceso bei teikiamos išvados. / The work is presented concepts related to odors, discussed the formation of odor sources. Examination of noxious odor impact on the environment and human health, the analysis of unpleasant odors and hazardous disposal methods and new methods of prevention measures. It also examines the interaction between the environment, interpreted odor detection technology, measurement techniques. Examines the institutions involved in odor management functions and responsibilities of the expert examination interview on odor management and control of the process and provided conclusions.
77

The Posterior Bed Nucleus of the Stria Terminalis Mediates Opposite-Sex Odor Preference in Male Syrian Hamsters (Mesocricetus Auratus)

Been, Laura Elizabeth 11 November 2008 (has links)
In Syrian hamsters, social behavior is mediated exclusively by chemosensory cues and circulating gonadal steroid hormones. Where these two signals are processed in the brain is unknown, but the posterior bed nucleus of the stria terminalis (pBNST) has been suggested as a candidate site. Therefore, we tested male hamsters’ preference for opposite-sex odors following excitotoxic lesions of the pBNST. Lesions of the pBNST (pBNST-X) eliminated male hamsters’ preference for opposite-sex odors. Furthermore, pBNST-X males spent significantly less time investigating female odors than clean odors and significantly less time investigating female odors than control males did. Lesions of the pBNST did not change male hamsters’ investigation of male odors. The deficits observed in pBNST-X males were not due to a failure to discriminate between odors, as pBNST-X males were able to distinguish between odors. Together, these data suggest the pBNST is critical for opposite-sex odor preference in male hamsters.
78

The alluring nature of episodic odor memory : Sensory and cognitive correlates across age and sex

Blåvarg, Christina January 2016 (has links)
Episodic memory for olfactory information is still relatively uncharted. The overall purpose of this thesis is to investigate the sensory and cognitive causes of the well-established age-related decline in olfactory episodic odor memory and of the age-independent sex difference in olfactory episodic memory. The purpose of Study I was to investigate the causes of the sex difference in olfactory episodic memory. The results show that the female advantage in episodic recognition memory seems to be explained by women´s higher aptitude in odor identification for familiar odors. With this background, the purpose of Study II was to investigate the age-related decline in olfactory episodic memory, with a particular eye to the role of odor identification. When controlling for the sensory variables olfactory threshold and odor quality discrimination, and the cognitive factor mental speed, the age-related deterioration in odor identification was eliminated. This suggests that changes in basic sensory and cognitive abilities underlie the age-related impairment in odor identification. The purpose of Study III was to investigate the role of recollective experience and intention to memorize for age-related and sex-related differences in episodic odor memory. Younger adults reported more experiences of remembering, and the elderly adults more experiences of feeling of knowing. The participants benefited from intentionality at encoding when the odors were unfamiliar, but intentionality did not affect memory for the familiar odors. The purpose of Study IV was to investigate the role of subjectively perceived qualities of the encoded odors for episodic memory across age and sex. Odors perceived as unpleasant, intense, and irritable were more easily remembered throughout the adult life span. The oldest adults selectively recognized the odors they rated as highly irritable indicating compensatory use of trigeminal activation. Overall, the result suggests that episodic odor memory rely heavily on both sensory and cognitive abilities, but in a different manner depending on demographic factors. The age-related decline appears to be driven by a sensory flattening disabling adequate cognitive processing. The age-independent sex difference on the other hand, is mainly cognitively mediated and driven by cognitive factors such as the ability to verbalize olfactory information.
79

Neuronal mechanisms of odor classification in the Drosophila antennal lobe: an optical imaging study

Dipt, Shubham 20 April 2015 (has links)
No description available.
80

Validação de protocolo de imunocastração em suínos desempenho animal e qualidade de carne /

Delbem, Nara Laiane Casagrande, 1987. January 2018 (has links)
Orientador: Roberto de Oliveira Roça / Resumo: Foram avaliados quatro protocolos da vacina Valora® (Ceva) para verificar a eficiência da vacina e diferenças na resposta produtiva, características de carcaça e qualidade da carne de suínos imunocastrados em relação aos castrados cirurgicamente. O total de 60 suínos machos, híbridos, alojados em baias individuais, foi dividido em cinco grupos (n = 12): animais castrados cirurgicamente (CC), vacinados com 8 e 19 semanas (V1); vacinados com 8 e 21 semanas (V2); vacinados com 8 e 23 semanas (V3) e vacinados com 8 e 24 semanas (V4) com delineamento experimental inteiramente casualizado. Os parâmetros peso, consumo de ração, conversão alimentar e rendimento de carcaça foram avaliados e, na véspera do abate, foram colhidas amostras de 4mL de sangue para mensurar a concentração sérica de LH e testosterona. No frigorífico foram avaliados peso e dimensões dos testículos. Após o resfriamento das carcaças, foram colhidas amostras do Musculus longissimus thoracis para as análises de qualidade da carne, incluindo a sensorial, e da gordura perianal para mensurar a concentração de escatol e androstenona. Nas condições do estudo, não foram detectadas diferenças entre os suínos castrados e imunocastrados, nem entre os protocolos de imunocastração para os parâmetros produtivos. Também não foi detectada diferença entre os tratamentos para o odor sexual e qualidade final da carne. Dessa forma, os protocolos de imunocastração determinaram resultados semelhantes à castração no desempenho, caracte... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Four Valora ® (Ceva) vaccine protocols were evaluated to verify vaccine efficacy and differences in the productive response, carcass characteristics and quality of the meat of pigs immunocastrated in relation to those surgically castrated. A total of 60 male pigs, hybrids, housed in individual pens were divided into five groups (n = 12) animals surgically castrated (CC), vaccinated with 8 and 19 weeks (V1); vaccinated at 8 and 21 weeks (V2); vaccinated at 8 and 23 weeks (V3) and vaccinated at 8 and 24 weeks (V4) with a completely randomized experimental design. The parameters weight, feed intake, feed conversion and carcass yield were evaluated and, on the eve of slaughter, samples of 4mL of blood were collected to measure the serum concentration of LH and testosterone. In the slaughterhouse were evaluated weight and dimensions of the testicles. After cooling of the carcasses, samples of the Longissimus thoracis muscle were collected for meat quality analyzes, including sensory analysis, and perianal fat to measure the concentration of escatol and androstenone. Under the study conditions, no differences were detected between castrated and immunocastrated pigs nor between the immunocastration protocols for the productive parameters. There was also no difference between treatments for sexual odor and final meat quality. Thus, immunocastration protocols determined results like castration in performance, carcass characteristics and meat quality. This is the first ever study to ev... (Complete abstract click electronic access below) / Doutor

Page generated in 0.0492 seconds