897 resultados para Ultrasonic reflection


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This study attempted to determine whether or not dialogue journal writing encouraged critical reflection in the adult ESL (English as a Second Language) learner. According to research in adult education and anecdotal evidence, the process ofdialogue journal writing can facilitate critical reflection in the adult learner. However, little research has been conducted to examine whether or not journal writing can facilitate critical reflection in the second language learner. As a result, ten low-intermediate level adult ESL students from Brock University's Intensive English Language Programme participated in a dialogue journal writing programme in their writing class. The participants wrote journal entries over a 10-week period, and were interviewed once throughout the process to determine their perceptions ofthe journal writing experience. They also were observed by the researcher throughout the journal writing sessions to establish whether any behaviours or intrusions might affect the participants' writing processes. After the content ofthe journals and the interviews, and the observations made by the researcher were analysed, it was confirmed that, for these participants, dialogue journal writing did not necessarily encourage critical reflection. Moreover, the participants' perceptions ofjournal writing were that it helped them to practise the syntax, vocabulary, and rhetorical patterns ofEnglish; nevertheless, it did not foster critical reflection or thinking.

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This qualitative study was designed to investigate aspects related to valuing and encouraging critical reflection in pre-service teacher education. An examination of the place and function of practicum logbooks as used at Covenant Canadian Reformed Teachers' College, a small private college which offers pre-service teacher education formed the core of the research. An analysis of the practicum logbooks written by five student teachers during three different practicum placements was performed at two levels. First, a content analysis served to identify general and specific categories within the practice teaching contextas a learning experience. Secondly, in-depth intuitive and thematic analyses of the entries which related specifically to reflection as a learning experience gave rise to critical questions. Throughout the process, the five participants formed an active and involved group of co-researchers, adding their voices to the narrative of the learning experience. Variables such as personality type, learning style and self-directedness added a dimension which deepened and emiched the study. The result of the study suggests that practicum logbooks form a valuable base for valuing and encouraging critical reflection in pre-service teacher education. The results also suggest that not all students appear to be equally capable of critical reflection. Recognizing that teacher education exists as a continuum appears to support the findings that in their journey along this continuum, student teachers not only move from reflection-on-action to reflection-in-action, but also from content to process to premise reflection. An awareness of contributing factors such as personality type, degree of risk-taking, preferred learning style and self-directedness on the part of teacher-educators will serve to create a climate of trust in which student teachers can safely develop critical reflection, using practicum logbooks as one possible medium.

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Ultrasonic vocalizations (USV) are emitted by rats in a number of social situations such as aggressive encounters, during sexual behavior, and during play in young rats, situations which are predominantly associated with strong emotional responses. These USV typically involve two distinct types of calls: 22 kHz calls, which are emitted in aversive situations and 50 kHz calls, which are emitted in non-aversive, appetitive situation. The 50 kHz calls are the focus of the present study and to date both the glutamatergic and the dopaminergic systems have been independently implicated in the production of these 50 kHz calls. The present study was conducted to examine a possible relationship between glutamate (GLU) and dopamine (DA) in mediating 50 kHz calls. It was hypothesized that the dopaminergic system plays a mediating role in 50 kHz calls induced by injections ofGLU into the anterior hypothalamic/preoptic area (AHPOA) in adult rats. A total of 68 adult male rats were used in this study. Rats' USV were recorded and analyzed in five experiments that were designed to test the hypothesis: in experiment 1, rats were treated with systemic amphetamine (AMPH) alone; in experiment 2, intra- AHPOA GLU was pretreated with systemic AMPH; in experiment 3, intra-AHPOA GLU was pretreated with intra-AHPOA AMPH; in experiment 4, rats were treated with high and low doses of intra-AHPOA AMPH only; in experiment 5, rats were treated with systemic haloperidol (HAL) as a pretreatment for intra-AHPOA GLU. Analysis of the results indicated that AMPH has a facilitatory effect on 50 kHz USV and that a relationship between DA and GLU in inducing 50 kHz calls does exist. The effect, however, was only observed when DA receptors were antagonized with HAL and was not seen with systemic AMPH pretreatments of intra-AHPOA GLU. The DAGLU relationship at the AHPOA was unclear.

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Ultrasonic vocalization plays an important role in intraspecies communication for rats. It has been well demonstrated that rats will emit 22kHz vocalization in stressfiil or threatening situations. Although the neural mechanism underlying vocahzation is not well understood, it is known that chohnergic input to the basal forebrain induces such alarm calls. A number of experiments have found that intracerebral injection of carbachol, a predominantly muscarinic agonist, into die anterior hypothalamic/preoptic area (AH/POA) rehably induces vocalization similar to naturally emitted ultrasonic calls. It has also been shown that carbachol has extensive inhibitory effects on neuronal firing in the same area. This result impUes that the inhibitory effects of carbachol in the AH/POA could trigger vocahzation, and that the GABAergic system could be involved. The purpose of this study is to investigate the effects ofGABA agonists and antagonists on flie production of carbachol induced 22kHz vocalization. The following hypotheses were examined: 1) apphcation ofGABA (a naturally occurring inhibitory neurotransmitter) will have a synergistic effect with carbachol, increasing vocalization; and 2) tiie apphcation ofGABA antagonists (picrotoxin or bicuculline) will reduce caibachol-induced vocalization. A total of sixty rats were implanted with stainless steel guide cannulae in the AH/POA area. After recovery, animals were locally pretreated with 1) GABA (l-40ng), 2) picrotoxin (1 .5^g) or bicuculhne (0.03ng), or 3) sahne; before injection with carbachol (1 .5^g). The resulting vocalization was measured and quantitated. The results indicate that pretreatment with GABA or GABA antagonists had no significant effect on vocalization. Local pretreatment with GABA did not potentiate the vocal response as measured by its duration, latraicy, and total number of calls. Similarly, pretreatment with picrotoxin or bicuculline had no effects on the same measures of vocalization. The results suggest tfiat chohnoceptive neurons involved in the production of alarm calls are not under direct GABAergic control.

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Rats produce ultrasonic vocalizations that can be categorized into two types of ultrasonic calls based on their sonographic structure. One group contains 22-kHz ultrasonic vocalization (USVs), characterized by relatively constant (flat) frequency with peak frequency ranging from 19 to 28-kHz, and a call duration ranging between 100 – 3000 ms. These vocalization can be induced by cholinomimetic agents injected into the ascending mesolimbic cholinergic system that terminates in the anterior hypothalamic-preoptic area (AH-MPO) and lateral septum (LS). The other group of USVs contains 50-kHz USVs, characterized by high peak frequency, ranging from 39 to 90-kHz, short duration ranging from 10-90 ms, and varying frequency and complex sonographic morphology. These vocalizations can be induced by dopaminergic agents injected into the nucleus accumbens, the target area for the mesolimbic dopaminergic system. 22-kHz USVs are emitted in situations that are highly aversive, such as proximity of a predator or anticipation of a foot shock, while 50 kHz USVs are emitted in rewarding and appetitive situations, such as juvenile play behaviour or anticipation of rewarding electrical brain stimulation. The activities of these two mesolimbic systems were postulated to be antagonistic to each other. The current thesis is focused on the interaction of these systems indexed by emission of relevant USVs. It was hypothesized that emission of 22 kHz USVs will be antagonized by prior activation of the dopaminergic system while emission of 50 kHz will be antagonized by prior activation of the cholinergic system. It was found that injection of apomorphine into the shell of the nucleus accumbens significantly decreased the number of carbachol-induced 22 kHz USVs from both AH-MPO and LS. Injection of carbachol into the LS significantly decreased the number of apomorphine-induced 50 kHz USVs from the shell of the nucleus accumbens. The results of the study supported the main hypotheses that the mesolimbic dopaminergic and cholinergic systems function in antagonism to each other.

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Rats produce ultrasonic vocalizations that can be categorized into two types of ultrasonic calls based on their sonographic structure. One group contains 22-kHz ultrasonic vocalization (USVs), characterized by relatively constant (flat) frequency with peak frequency ranging from 19 to 28-kHz, and a call duration ranging between 100 – 3000 ms. These vocalization can be induced by cholinomimetic agents injected into the ascending mesolimbic cholinergic system that terminates in the anterior hypothalamic-preoptic area (AH-MPO) and lateral septum (LS). The other group of USVs contains 50-kHz USVs, characterized by high peak frequency, ranging from 39 to 90-kHz, short duration ranging from 10-90 ms, and varying frequency and complex sonographic morphology. These vocalizations can be induced by dopaminergic agents injected into the nucleus accumbens, the target area for the mesolimbic dopaminergic system. 22-kHz USVs are emitted in situations that are highly aversive, such as proximity of a predator or anticipation of a foot shock, while 50 kHz USVs are emitted in rewarding and appetitive situations, such as juvenile play behaviour or anticipation of rewarding electrical brain stimulation. The activities of these two mesolimbic systems were postulated to be antagonistic to each other. The current thesis is focused on the interaction of these systems indexed by emission of relevant USVs. It was hypothesized that emission of 22 kHz USVs will be antagonized by prior activation of the dopaminergic system while emission of 50 kHz will be antagonized by prior activation of the cholinergic system. It was found that injection of apomorphine into the shell of the nucleus accumbens significantly decreased the number of carbachol-induced 22 kHz USVs from both AH-MPO and LS. Injection of carbachol into the LS significantly decreased the number of apomorphine-induced 50 kHz USVs from the shell of the nucleus accumbens. The results of the study supported the main hypotheses that the mesolimbic dopaminergic and cholinergic systems function in antagonism to each other.

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Teacher reflective practice is described as an effective method for engaging teachers in improving their own professional learning. Yet, some teachers do not understand how to effectively engage in the reflective processes, or prefer not to formalize the process through writing a reflective journal as taught in most teacher education programs. Developing reflective skills through the process of photography was investigated in this study as a strategy to allow enhanced teacher reflection for professional and personal growth. The process of photography is understood as the mindful act of photographing rather than focusing on the final product-the image. For this study, 3 practicing educators engaged in photographic exercises as a reflective process. Data sources included transcribed interviews, participant journal reflections, and sketchbook artifacts, as well as the researcher's personal journal notes. Findings indicated that, through the photographic process, (a) teacher participants developed new and individual strategies for professional leaming; and (b) teacher participants experienced shifts in the way they conceptualized their personal worldviews.

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Central administration of orexin-A has been shown to activate autonomic arousal in rats, reliably inducing anxiety-like behaviours in the open field. To date, there has yet to be a study investigating the role of orexin-A in the communication of such negative affective state. In the current study, forty-six adult male rats were chronically cannulated and administered orexin-A into the medial preoptic area/anterior hypothalamic area to determine the effect of this neuropeptide on anxiety-like behaviour and the production of 22 kHz aversive ultrasonic vocalizations. It was found that intracerebral administration of orexin-A increased autonomic arousal as measured by a significant increase in fecal boli output, however orexin-A did not significantly affect locomotor activity or induce 22 kHz calling. These data suggest that orexin-A is involved in the regulation of the autonomic aspect of anxiety-like behaviour but not in the vocal communication of such negative affect

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This research investigated professional identity transformation after personal loss. Through autoethnographic methods, I explore how my personal experience of my sister’s breast cancer and death affected my identity as a diabetes educator in the health culture. I discover a transformation of a professional who focuses on evidence-based medicine to a professional who values connection, therapeutic alliance, and mindfulness with patients and self in the diabetes education encounter. Using a holistic perspective on transformational learning, I integrate the poem “Wild Geese” to a collection of written narratives to connect my personal loss experience to my professional life. By unpacking the generated stories and using poetry, I conduct a process of critical and self-reflection to discover how my identity as a health professional has transformed and what makes meaning in my role as a diabetes educator in the health culture. I consider concepts of a conscious self, social relations and language and discover themes of knowledge exchange, food, and empathy as forms of language expression. These language expressions are not present in my professional life as I focus on rational, logical facts of evidence-based medicine and standardized education methods. Through this reflexive process, I hope to understand how my professional practice has changed, where I place an importance on connection, therapeutic alliance, and mindfulness. I move away from always “doing” in my professional life to focus on my state of “being” in my professional world. Rather than knowledge acquisition as the only factor in professional development, this study contributes to an understanding of additional qualities health professionals may consider that focus on the patient education encounter.

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There is extensive evidence that the mesolimbic dopamine system underlies the production of 50 kHz ultrasonic vocalizations in rats. In particular, the shell of the nucleus accumbens is associated with generation of frequency modulated 50 kHz calls (a specific type of 50 kHz call which can be subdivided into various subtypes). There is also evidence that amphetamine administered systemically preferentially increases the proportion of trill and step calls compared to other frequency modulated 50 kHz subtypes. The purpose of this study was to investigate the effect of drug administration route and the role of the nucleus accumbens shell in amphetamine-induced 50 kHz call profile in the rat. Three experiments investigated this by using subcutaneous and intra-accumbens microinjections of amphetamine, as well as procaine (a local anesthetic) blockade of the nucleus accumbens. Ultrasonic vocalizations were recorded digitally from 24 rats and were analysed for sonographic structure based on general call parameters. The results of the three experiments were partially supportive of the hypotheses. Systemic amphetamine was found to induce greater bandwidth in 50 kHz calling compared to spontaneous calls in a vehicle condition. Systemic amphetamine was also found to preferentially increase the proportion of trill and step subtypes compared to vehicle. Moreover, there was no difference in the proportions of 50 kHz subtypes resulting from intracerebral or systemic application of amphetamine. There was, however, a significant difference for bandwidth, with systemic amphetamine inducing greater bandwidth over intraaccumbens application. Procaine blockade of the nucleus accumbens shell paired with subcutaneous amphetamine produced no difference in bandwidth of calls compared with those after a vehicle pre-treatment similarly paired. There was no reduction in the proportions of trill and step 50 kHz subtypes as well, with the procaine condition showing significantly greater proportion of step calls. The results of the study support a role for the iii nucleus accumbens shell in the amphetamine-induced changes on 50 kHz call profile. They also indicate there are more regions and pathways involved in generating 50 kHz calls than the projections from the ventral tegmental area to the nucleus accumbens. The implications of this work are that frequency modulated 50 kHz subtypes may be generated by distinct neurophysiological mechanisms and may represent a profitable avenue for investigating different circuits of 50 kHz call categories in the rat.

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The present thesis investigates the responses to reflection in both the crayfish Procambarus clarkii and the fruit fly Drosophila melanogaster. Responses to reflection in crayfish depend on social status and the current work suggests that learning and memory consolidation are required for these responses to be altered. Crayfish were treated to either massed or spaced training fights prior to reflection testing. The results show that subordinate crayfish treated to spaced training display a response typical of subordinate crayfish but subordinate crayfish treated to massed training exhibit a response typical of dominant crayfish. Fruit flies are shown to be attracted to reflection and responses to reflection are described here for the first time. Responses in fruit flies are shown to be dependent on social status. The frequency of behaviours were altered in isolated flies but not socialized flies. The addition of pheromones cVA and 7,11-HD were used to investigate how the addition of chemical cues altered responses to reflection in fruit flies. Socialized fruit flies treated with cVA exhibited an increase in the frequency of behaviours on both mirrored and clear glass walls, while isolated flies exhibited a decrease. Socialized flies treated with 7,11-HD spent more time on mirrored walls compared to glass walls, whereas the frequency of all behaviours were decreased in isolated flies treated with 7,11-HD.

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Une multitude de recherches évaluatives ont démontré que les victimes de crime, qu’elles soient victimes d’un crime contre les biens ou contre la personne, apprécient l’approche réparatrice. Cependant, nous sommes toujours à la recherche des facteurs théoriques qui expliqueraient la satisfaction des victimes en ce qui concerne leur expérience avec les interventions réparatrices. La recherche décrite dans cette thèse concerne l’exploration des facteurs contribuant à la satisfaction des victimes de crime avec l’approche réparatrice ainsi que ses liens avec la théorie de justice procédurale. Selon la théorie de justice procédurale, la perception de justice n’est pas uniquement associée à l’appréciation du résultat d’une intervention, mais également à l’appréciation de la procédure, et que la procédure et le résultat peuvent être évalués de façon indépendante. Les procédures qui privilégient la confiance, la neutralité et le respect, ainsi que la participation et la voix des parties sont plus appréciées. Notre objectif de recherche était d’explorer l’analogie entre l’appréciation de la justice réparatrice et le concept de justice procédurale. En outre, nous avons voulu déterminer si la justice réparatrice surpasse, en termes de satisfaction, ceux prévus par la théorie de justice procédurale. Nous avons également examiné la différence dans l’appréciation de l’approche réparatrice selon le moment de l’application, soit avant ou après adjudication pénale. Ainsi, nous avons exploré le rôle d’une décision judiciaire dans l’évaluation de l’approche réparatrice. Pour répondre à nos objectifs de recherche, nous avons consulté des victimes de crime violent au sujet de leur expérience avec l’approche réparatrice. Nous avons mené des entrevues semi-directives avec des victimes de crime violent qui ont participé à une médiation auteur-victime, à une concertation réparatrice en groupe ou aux rencontres détenus-victimes au Canada (N=13) et en Belgique (N=21). Dans cet échantillon, 14 répondants ont participé à une intervention réparatrice avant adjudication judiciaire et 14 après adjudication. Nous avons observé que l’approche réparatrice semble être en analogie avec la théorie de justice procédurale. D’ailleurs, l’approche réparatrice dépasse les prémisses de la justice procédurale en étant flexible, en offrant de l’aide, en se concentrant sur le dialogue et en permettant d’aborder des raisons altruistes. Finalement, le moment de l’application, soit avant ou après adjudication, ne semble pas affecter l’appréciation des interventions réparatrices. Néanmoins, le rôle attribué à l’intervention réparatrice ainsi que l’effet sur l’évaluation du système judiciaire diffèrent selon le moment d’application. Les victimes suggèrent de continuer à développer l’approche réparatrice en tant que complément aux procédures judiciaires, plutôt qu’en tant que mesure alternative. Les témoignages des victimes servent la cause de l’offre réparatrice aux victimes de crime violent. L’offre réparatrice pourrait aussi être élargie aux différentes phases du système judiciaire. Cependant, la préférence pour l’approche réparatrice comme complément aux procédures judiciaires implique la nécessité d’investir également dans la capacité du système judiciaire de répondre aux besoins des victimes, tant sur le plan de la procédure que sur le plan du traitement par les autorités judiciaires.

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La réflexion est considérée comme un élément significatif de la pédagogie et de la pratique médicales sans qu’il n’existe de consensus sur sa définition ou sur sa modélisation. Comme la réflexion prend concurremment plusieurs sens, elle est difficile à opérationnaliser. Une définition et un modèle standard sont requis afin d’améliorer le développement d’applications pratiques de la réflexion. Dans ce mémoire, nous identifions, explorons et analysons thématiquement les conceptualisations les plus influentes de la réflexion, et développons de nouveaux modèle et définition. La réflexion est définie comme le processus de s’engager (le « soi » (S)) dans des interactions attentives, critiques, exploratoires et itératives (ACEI) avec ses pensées et ses actions (PA), leurs cadres conceptuels sous-jacents (CC), en visant à les changer et en examinant le changement lui-même (VC). Notre modèle conceptuel comprend les cinq composantes internes de la réflexion et les éléments extrinsèques qui l’influencent.

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The thesis investigated the elastic properties and phase transitions in selected mixed sulphate crystals – Lithium Hydrazinium Sulphate [LiN2H2SO4], Lithium Ammonium Sulphate [LiNH4SO4] and Lithium Potassium Sulphate [LiKSO4] – using ultrasonic technique. The pulse echo overlap technique has been used for measuring ultrasonic velocity and its dependence on temperature along different directions with waves of longitudinal and transverse polarizations. Two major numerical techniques and the corresponding computer programs developed as part of present work are presented in this thesis. All the 9 elastic constants of LHS are determined accurately from ultrasonic measurements and applying misorientation correction refines the constants. Ultrasonic measurements are performed in LAS to determine the elastic constants and to study the low temperature phase transitions. Temperature variation studies of elastic constant of LAS are performed for 6 different modes of propagation for heating and cooling at low temperatures. All the 5 independent elastic constants of LPS is determined using ultrasonic measurements. It is concluded that LPS crystal does not undergo a phase transition near this temperature. A comparison of the three crystals studied shows that LPS has maximum number of phase transitions and LHS has the least number. It is interesting to note that LPS has the simplest formula unit among the three. There is considerable scope for the future work on these crystals and others belonging to the sulphate family.

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The present work is an attempt to probe the elastic properties in some dielectric ceramics, by using ultrasonic pulse echo overlap technique. The base Ba6-xSm8+2xTi18O54 and Ca5Nb2TiO12 are very important dielectrics ceramics used for microwave communication as well as for substrate materials. Ultrasonic is one of the most widely used and powerful techniques to measure elastic properties of solids. The ultrasonic technique is nondestructive in nature and the measurements are relatively straightforward to perform. One unique advantantage of the ultrasonic technique is that both static and dynamic properties can be measured simultaneously. The velocity and attenuation coefficients of the ultrasonic waves propagating through a medium are related to the microscopic structure of the material and they provide valuable information about the structural changes in the system. Among the various ultrasonic techniques, the pulse echo overlap method is the most accurate and precise one. In the present case the decreased elastic properties of Cas-XMg,Nb2TiO12 and Cas-,ZnNb2TiO12 ceramics can be attributed to their mixture phases beyond x = 1. Moreover, the abrupt change in elastic properties observed for x >1 can also be correlated to the structural transformation of the materials from their phase pure form to mixture phases for higher extent of substitution of the concerned material . Ca4(ANb2Ti)012 (A = Mg, Zn) is the strongest compound with the maximum values for elastic properties . This could be due to the possible substitution of Mg/Zn ions with lesser radius [25] than Ca2+ in perovskite B-site of Ca(Cali4Nb2i4Tili4) O3 material to contribute more ordering and symmetry to the system [20]. All other compositions (x > 1) contain mixed-phases and for such mixed-phase samples, the mechanical properties are difficult to explain.