929 resultados para covert recordings


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Using event-related brain potentials, the time course of error detection and correction was studied in healthy human subjects. A feedforward model of error correction was used to predict the timing properties of the error and corrective movements. Analysis of the multichannel recordings focused on (1) the error-related negativity (ERN) seen immediately after errors in response- and stimulus-locked averages and (2) on the lateralized readiness potential (LRP) reflecting motor preparation. Comparison of the onset and time course of the ERN and LRP components showed that the signs of corrective activity preceded the ERN. Thus, error correction was implemented before or at least in parallel with the appearance of the ERN component. Also, the amplitude of the ERN component was increased for errors, followed by fast corrective movements. The results are compatible with recent views considering the ERN component as the output of an evaluative system engaged in monitoring motor conflict.

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The mismatch negativity is an electrophysiological marker of auditory change detection in the event-related brain potential and has been proposed to reflect an automatic comparison process between an incoming stimulus and the representation of prior items in a sequence. There is evidence for two main functional subcomponents comprising the MMN, generated by temporal and frontal brain areas, respectively. Using data obtained in an MMN paradigm, we performed time-frequency analysis to reveal the changes in oscillatory neural activity in the theta band. The results suggest that the frontal component of the MMN is brought about by an increase in theta power for the deviant trials and, possibly, by an additional contribution of theta phase alignment. By contrast, the temporal component of the MMN, best seen in recordings from mastoid electrodes, is generated by phase resetting of theta rhythm with no concomitant power modulation. Thus, frontal and temporal MMN components do not only differ with regard to their functional significance but also appear to be generated by distinct neurophysiological mechanisms.

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This thesis is an experimental study regarding the identification and discrimination of vowels, studied using synthetic stimuli. The acoustic attributes of synthetic stimuli vary, which raises the question of how different spectral attributes are linked to the behaviour of the subjects. The spectral attributes used are formants and spectral moments (centre of gravity, standard deviation, skewness and kurtosis). Two types of experiments are used, related to the identification and discrimination of the stimuli, respectively. The discrimination is studied by using both the attentive procedures that require a response from the subject, and the preattentive procedures that require no response. Together, the studies offer information about the identification and discrimination of synthetic vowels in 15 different languages. Furthermore, this thesis discusses the role of various spectral attributes in the speech perception processes. The thesis is divided into three studies. The first is based only on attentive methods, whereas the other two concentrate on the relationship between identification and discrimination experiments. The neurophysiological methods (EEG recordings) reveal the role of attention in processing, and are used in discrimination experiments, while the results reveal differences in perceptual processes based on the language, attention and experimental procedure.

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Many Ophidiidae are active in dark environments and display complex sonic apparatus morphologies. However, sound recordings are scarce and little is known about acoustic communication in this family. This paper focuses on Ophidion rochei which is known to display an important sexual dimorphism in swimbladder and anterior skeleton. The aims of this study were to compare the sound producing morphology, and the resulting sounds in juveniles, females and males of O. rochei.Results: Males, females, and juveniles possessed different morphotypes. Females and juveniles contrasted with males because they possessed dramatic differences in morphology of their sonic muscles, swimbladder, supraoccipital crest, and first vertebrae and associated ribs. Further, they lacked the ‘rocker bone’ typically found in males. Sounds from each morphotype were highly divergent. Males generally produced non harmonic, multiple-pulsed sounds that lasted for several seconds (3.5 ± 1.3 s) with a pulse period of ca. 100 ms. Juvenile and female sounds were recorded for the first time in ophidiids. Female sounds were harmonic, had shorter pulse period (±3.7 ms), and never exceeded a few dozen milliseconds (18 ± 11 ms). Moreover, unlike male sounds, female sounds did not have alternating long and short pulse periods. Juvenile sounds were weaker but appear to be similar to female sounds.Conclusions: Although it is not possible to distinguish externally male from female in O. rochei, they show a sonic apparatus and sounds that are dramatically different. This difference is likely due to their nocturnal habits that may have favored the evolution of internal secondary sexual characters that help to distinguish males from females and that could facilitate mate choice by females. Moreover, the comparison of different morphotypes in this study shows that these morphological differences result from a peramorphosis that takes place during the development of the gonads

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Chorioamnionitis is known to be an important risk factor underlying preterm delivery, and it has also been suggested to associate with brain lesions and deviant neurological development in both preterm and term infants. Cytokines are believed to be the link causing the deleterious effects of inflammation to the nervous system. Their genetic regulation has also been suggested to play a role, as interleukin (IL)-6 -174 and -572 genotypes, which partly regulate IL-6 synthesis responses, have been connected with deviant neurological development in preterm infants. We evaluated the association of histological chorioamnionitis with brain lesions, regional brain volumes, and the functioning of the auditory pathway in very low birth weight/very low gestational age (VLBW/VLGA) infants. In addition, we investigated the association between IL-6 -174 and -572 genotypes and histological chorioamnionitis, neonatal infections, and brain lesions and regional brain volumes in VLBW/VLGA infants. This study is a part of a larger multidisciplinary project PIPARI (Development and Functioning of Very Low Birth Weight Infants from Infancy to School Age), in which the survivors of a 6-year cohort of VLBW/VLGA infants (n=274) are being followed until school age in Turku University Central Hospital, Finland. Placental samples were collected in the delivery room, and were analyzed for histological inflammatory findings. Blood samples from the infants were collected and DNA was genotyped for IL-6-174 and -572 polymorphisms (GG/GC/CC). Brain ultrasound examinations were performed repeatedly in the neonatal intensive care unit and at term age, and were analysed for structural brain lesions. Brain magnetic resonance imaging was performed at term age, and was analysed for regional brain volumes. In addition, diffusion tensor imaging was performed at term, and was used to analyse fractional anisotrophy and the apparent diffusion coefficient of inferior colliculus. The brainstem auditory evoked potential recordings were carried out according to the routine clinical procedure at median age of 30 days after term age. In our study, we found that histological chorioamnionitis was not an independent risk factor for brain lesions, reduced regional brain volumes or abnormal functioning of the auditory pathway in VLBW/VLGA infants. In addition, we found that IL-6 -174 GG and -572 GC genotypes were associated with a higher incidence of histological chorioamnionitis, and that -174 CC genotype associated with higher incidence of septicaemia. The analysed IL-6 genotypes were not associated with other brain lesions, but a reduced volume of basal ganglia and thalami was associated with IL-6 -174 CC and -572 GG genotypes. In conclusion, our findings suggest that histological chorioamnionitis is not an independent risk factor for the brain development of VLBW/VLGA infants, or that the risk caused by inflammation does not exceed the risks attributed to other underlying pathologies behind preterm deliveries. In addition, our findings give reason to propose that IL-6 promoter genotypes have a role in the defence against serious infections and in the brain development of VLBW/VLGA infants.

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Noradrenergic neurotransmission has been associated with the modulation of higher cognitive functions mediated by the prefrontal cortex. In the present study, the impact of noradrenergic stimulation on the human action-monitoring system, as indexed by eventrelated brain potentials, was examined. After the administration of a placebo or the selective 2 -adrenoceptor antagonist yohimbine, which stimulates firing in the locus ceruleus and noradrenaline release, electroencephalograpic recordings were obtained from healthy volunteers performing a letter flanker task. Yohimbine led to an increase in the amplitude of the error-related negativity in conjunction with a significant reduction of action errors. Reaction times were unchanged, and the drug did not modify the N2 in congruent versus incongruent trials, a measure of preresponse conflict, or posterror adjustments as measured by posterror slowing of reaction time. The present findings suggest that the locus ceruleusnoradrenaline system exerts a rather specific effect on human action monitoring.

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La tècnica de l’electroencefalograma (EEG) és una de les tècniques més utilitzades per estudiar el cervell. En aquesta tècnica s’enregistren els senyals elèctrics que es produeixen en el còrtex humà a través d’elèctrodes col•locats al cap. Aquesta tècnica, però, presenta algunes limitacions a l’hora de realitzar els enregistraments, la principal limitació es coneix com a artefactes, que són senyals indesitjats que es mesclen amb els senyals EEG. L’objectiu d’aquest treball de final de màster és presentar tres nous mètodes de neteja d’artefactes que poden ser aplicats en EEG. Aquests estan basats en l’aplicació de la Multivariate Empirical Mode Decomposition, que és una nova tècnica utilitzada per al processament de senyal. Els mètodes de neteja proposats s’apliquen a dades EEG simulades que contenen artefactes (pestanyeigs), i un cop s’han aplicat els procediments de neteja es comparen amb dades EEG que no tenen pestanyeigs, per comprovar quina millora presenten. Posteriorment, dos dels tres mètodes de neteja proposats s’apliquen sobre dades EEG reals. Les conclusions que s’han extret del treball són que dos dels nous procediments de neteja proposats es poden utilitzar per realitzar el preprocessament de dades reals per eliminar pestanyeigs.

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Aquest projecte treballa sobre la possibilitat d'aplicar tècniques d'enregistrament binaural en animals, en concret, en una cabra domèstica. Mitjançant uns micròfons col·locats dins les seves orelles i una petita càmera de vídeo muntada sobre el seu cap, s'obté un material audiovisual que permet fer-se una idea aproximada de com és la seva percepció del món. En base a un estudi de cognició comparada, es pretén trobar maneres de transformar els enregistraments obtinguts per tal d'adaptar el marc psicoacústic humà al de l'animal. L'objectiu és que una persona pugui sentir com ho fa un animal, encara que sigui d'una manera aproximada. Els materials obtinguts al llarg dels enregistraments són el punt de partida per a la construcció de paisatges sonors i peces audiovisuals diverses. Així doncs, el treball s'inicia amb el disseny i construcció d'un micròfon binaural, continua amb enregistraments de camp en animals i acaba amb l'edició, el processat i la composició dels paisatges sonors finals.

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This work describes a mentorship experience. Mentorship of novice teachers by experienced teachers is an important aspect in training teachers for universities. The strategy followed in this work consisted of a double improvement cycle (or clinical supervision cycle), based on the use of recordings of classes. Each of these cycles included planning, recording, viewing and analysis. Conclusions were reached in a final meeting after video analysis. In order to systematize the viewing, analysis and assessment of the videos, an observation test was employed. Class planning, contents, methodology, and verbal and nonverbal communication skills were evaluated using the test.

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Vanhemmat keskoslasten kivun lievittäjinä Tutkimuksen tarkoituksena oli kehittää uusi kivunlievitysmenetelmä, Vanhempien käsikapalo, keskoslasten kivunhoitoon vastasyntyneiden teho-osastolla. Vanhempien käsikapalon tehokkuutta verrattiin kahdessa satunnaistetussa kontrolloidussa crossover-tutkimusasetelmassa ei-lääkkeelliseen näyttöön perustuvaan hoitoon (P.O. glukoosiliuos), lääkkeelliseen menetelmään (I.V. oksikodoni) ja lumeeseen (P.O. vesi) tai kontrolli hoitoon kantapääpiston ja hengitysteiden imemisen aikana. Lisäksi mitattiin kivunhoidon lyhytaikaisia sivuvaikutuksia (hapetuksen- ja pulssinlasku) ja pidempiaikaisia vaikutuksia uneen. Tutkittujen lasten ikä oli 28 raskausviikkoa (n = 20) ja 28 1/7 (n = 20). Toimenpidekipua arvioitiin Premature Infant Pain Profile (PIPP) -kipumittarilla. Interventioiden jälkeen unen rakenne analysoitiin 13 tunnin polysomnografia-rekisteröinneistä. Viimeisessä vaiheessa haastateltiin äitejä (n = 23), jotka olivat käyttäneet vanhempien käsikapaloa 2–4 viikkoa vastasyntyneiden teho-osastolla, strukturoidulla the Clinical Interview for Parents of High-Risk Infants -haastattelulla, johon oli lisätty kysymyksiä lapsen kivunhoidosta. Kantapääpiston aikana PIPP–pisteet olivat merkitsevästi matalampia P.O. glukoosiliuoksella (ka 4,85 ± 1,73, p ≤ 0,001) ja vanhempien käsikapalolla (ka 5,20 ± 1,70, p = 0,004) verrattuna lumeeseen (ka 7,05 ± 2,16). Hengitysteiden imemisen yhteydessä PIPP–pisteet olivat matalampia P.O. glukoosiliuoksella (ka 11,05 ± 2,31, p = 0,014) ja vanhempien käsikapalolla (ka 11,25 ± 2,47, p = 0,034) verrattuna lumeeseen (ka 12,40 ± 2,06). Oksikodonin teho oli verrattavissa lumeeseen kummankin toimenpiteen aikana. P.O. glukoosiliuoksen (21,3 %) ja lumeen (12,5 %) annosteluun liittyi merkittävästi enemmän lyhytaikaisia sivuvaikutuksia verrattuna oksikodoniin (5 %) tai vanhempien käsikapaloon (5 %). Oksikodoni muutti keskoslasten unen rakennetta vähentämällä merkittävästi aktiivisen unen määrää verrattuna muihin hoitoihin. Vanhemmat suhtautuivat positiivisesti käsikapalon käyttöön. Äitien osallistuminen kivunhoitoon voitiin jaotella kolmeen eri tyylin, jotka selittyivät äidin kiintymyksen tunteilla ja lapsen tehohoitoon liittyvällä stressillä. Vanhempien käsikapalo on suositeltavampi lyhyen toimenpidekivun lievittäjä kuin P.O. glukoosiliuos tai I.V. oksikodoni, kun tehokkuus, turvallisuus ja perhe otetaan huomioon.

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This research is a phenomenological-hermeneutic case-study based on the methods of action research in which narrative methods are used to examine a process drama carried out in a day-care centre, focusing on its dialogicality and possibilities of offering children and adults ethical problems to examine and solve. A process drama built around a story was carried out in a Finnish day-care centre in 1999 with the aim of bringing ethical education to the level of conscious consideration and action. The research consists of two case-studies. The first focuses on Risto, one of the children who participated in the process, his actions in group situations, his commitment to the rules set by the leaders, his attitude towards the group and its members as well as the common agreements concerning the group, and his solutions to fictive dilemmas in relation to Lawrence Kohlberg’s and Carol Gilligan’s concepts of justice and care. On this basis conclusions are made on how drama can be applied to dealing with ethical dilemmas with children aged four to seven. The second case-study searches for ethical themes and signs of dialogicality in the story that was created together by the children and leaders, and in the action that took place in the drama sessions. The subjects of this study consist of two groups participating in the process drama, both consisting of seven children aged four to seven. Narratives were written on each child based on his/her participation in four drama sessions selected to be used in this study. The narratives include the writer’s interpretations of the dialogicality of the drama and the ethical themes observed and recognised in the videos and in the transcriptions of the video recordings. The description and interpretation of the dialogicality and the ethical themes observed in the drama sessions is based on the researcher’s dialogue with the writings of Georg Henrik von Wright, Martin Buber and Mihail Bahtin, as well as Nicholas C. Burbules’ definitions of the basic conditions for dialogical teaching. As a result of the study, drama activity proved to be a means by which dialogically abstract ethical questions and conflicts could be dealt with even with young children and which revealed the zone of proximal development of both children and adults. Drama became a stage for ethical growth and dialogicality, and the common play of children and adults could be seen as an indicator of deep dialogicality. On the basis of this study, it can be said that drama is a very suitable way of establishing a shape and form of ethical education in which it is possible to make planned, target-oriented progress and which can be consciously observed by following the development of both the child and the educator.

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The aim of this research was to understand the reasoning developed by medical students in a public university in Brazil. This research on education included semi-structured interviews and film recordings of interns discussing 10 clinical cases. A sample of 16 interns analyzed cases presented on a notebook computer with a webcam. They were instructed to verbalize all their thoughts on the procedures they would use. The film recordings and transcripts of the interviews were analyzed. Quantitative data was evaluated using Yates' chi-squared test and speech analysis was used to evaluate the transcripts. The theme worked on in the practice of reasoning was: the student's perceptions of their clinical practice. Of the 160 diagnoses, 57% were done with analytical reasoning and 43% with non-analytical reasoning. The hypothetical deductive method was employed by 31% of the interns and the inductive method was employed by 69%. The diagnostic accuracy was 81% correct for easy cases and 85% correct for difficult cases. We observed two empirical categories: the cognitive universe of the student and the patient's context.

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Kirjallisuusarvostelu

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Preattentive perception of occasional deviating stimuli in the stream of standard stimuli can be recorded with cognitive event-related potential (ERP) mismatch negativity (MMN). The earlier detection of stimuli at the auditory cortex can be examined with N1 and P2 ERPs. The MMN recording does not require co-operation, it correlates with perceptual threshold, and even complex sounds can be used as stimuli. The aim of this study was to examine different aspects that should be considered when measuring discrimination of hearing with ERPs. The MMN was found to be stimulusintensity- dependent. As the intensity of sine wave stimuli was increased from 40 to 80 dB HL, MMN mean amplitudes increased. The effect of stimulus frequency on the MMN was studied so that the pitch difference would be equal in each stimulus block according to the psychophysiological mel scale or the difference limen of frequency (DLF). However, the blocks differed from each other. The contralateral white noise masking (50 dB EML) was found to attenuate the MMN amplitude when the right ear was stimulated. The N1 amplitude was attenuated and, in contrast, P2 amplitude was not affected by contralateral white noise masking. The perception and production of vowels by four postlingually deafened patients with a cochlear implant were studied. The MMN response could be elicited in the patient with the best vowel perception abilities. The results of the studies show that concerning the MMN recordings, the stimulus parameters and recording procedure design have a great influence on the results.

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Personalised ubiquitous services have rapidly proliferated due technological advancements in sensing, ubiquitous and mobile computing. Evolving societal trends, business and the economic potential of Personal Information (PI) have overlapped the service niches. At the same time, the societal thirst for more personalised services has increased and are met by soliciting deeper and more privacy invasive PI from customers. Consequentially, reinforcing traditional privacy challenges and unearthed new risks that render classical safeguards ine ective. The absence of solutions to criticise personalised ubiquitous services from privacy perspectives, aggravates the situation. This thesis presents a solution permitting users' PI, stored in their mobile terminals to be disclosed to services in privacy preserving manner for personalisation needs. The approach termed, Mobile Electronic Personality Version 2 (ME2.0), is compared to alternative mechanisms. Within ME2.0, PI handling vulnerabilities of ubiquitous services are identi ed and sensitised on their practices and privacy implications. Vulnerability where PI may leak through covert solicits, excessive acquisitions and legitimate data re-purposing to erode users privacy are also considered. In this thesis, the design, components, internal structures, architectures, scenarios and evaluations of ME2.0 are detailed. The design addresses implications and challenges leveraged by mobile terminals. ME2.0 components and internal structures discusses the functions related to how PI pieces are stored and handled by terminals and services. The architecture focusses on di erent components and their exchanges with services. Scenarios where ME2.0 is used are presented from di erent environment views, before evaluating for performance, privacy and usability.