274 resultados para Swim


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This thesis reports on research showing the survival discourse of beginning teaching has shifted from sink or swim metaphors to describe surviving transition shock and classroom management concerns to surviving contract employment. Beginning teachers are neither sinking nor swimming in this liminal state. Rather, it is as though they are on a lifeboat where they cannot feel like a ‘real’ teacher until they can operate with certainty.

Interrogating the experiences of beginning teachers, and the transformation of their identity in their first year (1yr) of teaching, the thesis explores research participants’ firsts as epiphanic or revelatory moments of identity transformation. Participants were followed for three years from upon completion of their teacher education, through their first year of teaching, up to the beginning of their third year in the profession. The major finding was that while contemporary understandings of professional identity highlight the transformative nature of the phenomenon,  contract employment had the most impact on these teachers’ identity transformation.

Teachers’ perceptions of their own professional identity affect their efficacy and professional development as well as their ability and willingness to cope with educational change (Beijaard, Verloop & Vermunt 2000). It has been reported by the Australian Education Union (AEU) and in the Victorian media in recent years that up to 50% of beginning teachers are leaving the profession within their first five years. The reasons given for this level of
attrition include workload, pay, and behaviour management, among the top concerns of beginning teachers. These categories have positioned beginning teachers in a survival discourse for many years, yet there is more to beginning teachers’ intentions to leave than their struggles to survive in the classroom. More recently in Victoria what it means to ‘survive’ has shifted to surviving the pervasive contractual nature of beginning teachers’
employment conditions.

This qualitative study seeks to question what remains concealed with regard to beginning teachers’ experiences through an investigation of the differences between and within individuals, allowing categories of description to emerge from the data rather than pre-determining categories of investigation. Data was collected from twelve participants through individual semi-structured interviews and written communication. A theatre-based research approach to representing the participants’ experiences was employed, culminating in a performance titled ‘The First Time’. The processes of scripting, rehearsing, and performing, were utilised to analyse and represent the data to expert audiences. In an aim to uncover questions that have been buried by answers, the research is oriented as a
phenomenographic inquiry. This mode of inquiry seeks to describe, analyse, and understand (Marton 1981) the qualitatively different experiences 1yr teachers undergo in their identity formation and transformation.

The results of this research reveal the destabilising effect of short-term contracts so prevalent in the current context; that status and belonging are central to 1yr teachers’ identity work. Status and belonging are positioned within survival, liminal, and hegemonic discourses; and expressed through artefacts as symbols of belonging. The low status ascribed to contractual work has a clear impact on beginning teachers’ commitment to the profession.

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Sea turtle movements often occur in open-sea unsheltered areas, and are therefore likely to be influenced by major oceanographic processes. Only recently has work started to examine the possible relationships of these movements with dynamic oceanic features, and consequently a clear picture of such interaction is only available in a few cases. Newborn sea turtles are thought to rely on oceanic currents to reach their pelagic nursery habitats. The actual extent and timing of these developmental migrations are known for only a few populations, but these movements probably last several years and range over thousands of km. Large juveniles that have been tracked during their pelagic stage were found to make long-distance movements, sometimes swimming against the prevailing currents. Older juveniles of most species leave the pelagic habitat to recruit to neritic developmental habitats. This is a very poorly documented phase of the sea turtle life-cycle, and the few available indications show that turtles may have to swim actively for enormous distances to counterbalance their previous drift with the current. The course and extent of adult postnesting migrations vary greatly among different turtle species, but two main patterns are evident. Some species, like green, hawksbill and loggerhead turtles, shuttle between the nesting beach and a specific feeding area used for the entire inter-reproductive period. In these cases, individuals swim, rather than drift, to complete their journeys, with possible advection due to currents sometimes helping them to quickly reach their target, but sometimes providing navigational challenges. Other species such as the olive ridley and the leatherback turtle, leave the coastal nesting areas to reach the pelagic environment where they forage, and perform wandering movements. Major oceanographic processes (such as main currents and eddies) have been recently shown to have a remarkable influence on leatherback movements, making it questionable whether these journeys are to be considered migrations or, rather, prolonged stays in vast feeding areas.

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Green turtles (Chelonia mydas) swim from foraging grounds along the Brazilian coast to Ascension Island to nest, over 2200 km distant in the middle of the equatorial Atlantic. To test the hypothesis that turtles use wind-borne cues to locate Ascension Island we found turtles that had just completed nesting and then moved three individuals 50 km northwest (downwind) of the island and three individuals 50 km southeast (upwind). Their subsequent movements were tracked by satellite. Turtles released downwind returned to Ascension Island within 1, 2 and 4 days, respectively. By contrast, those released upwind had far more difficulty in relocating Ascension Island, two eventually returning after 10 and 27 days and the third heading back to Brazil after failing to find its way back to the island. These findings strongly support the hypothesis that wind-borne cues are used by turtles to locate Ascension Island.

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The depth and swim speed of a green turtle (Chelonia mydas) were measured during the internesting period in Cyprus. For dives to the seabed (U-dives) we used these data to determine dive angles. Typically the turtle initially descended at a steep angle ([similar]60°) but as the dive continued this angle lessened until the turtle approached the seabed at an average angle of [similar]15°. This systematic change in descent angle is consistent with the prediction that the energetic implications of dive angle are most important at the start of the dive when the turtle is fighting to overcome its positive buoyancy. On leaving the seabed, the turtle often seemed to rise passively.

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Here we provide baseline data on the distribution and abundance of Mola mola within the Irish and Celtic Seas, made during aerial surveys from June to October during 2003–2005. These data were considered in conjunction with concurrent observations of three potential jellyfish prey species found throughout the region: Rhizostoma octopus, Chrysaora hysoscella and Cyanea capillata. A total area of 7850 km2 was surveyed over the three years with an observed abundance of 68 sunfish giving a density of 0.98 ind/100 km2. Although modest, these findings highlight that the species is more common than once thought around Britain and Ireland and an order of magnitude greater than the other apex jellyfish predator found in the region, the leatherback turtle (Dermochelys coriacea). Furthermore, the distribution of sunfish sightings was inconsistent with the extensive aggregations of Rhizostoma octopus found throughout the study area. The modelled distributions of predator–prey co-occurrence (using data for all three jellyfish species) was less than the observed co-occurrence with the implication that neither jellyfish nor sunfish were randomly distributed but co-occurred more in the same areas than expected by chance. Finally, observed sunfish were typically small ([similar]1 m or less) and seen to either bask or actively swim at the surface.

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Why are beginning teachers leaving the profession in large numbers? Are they leaving because of their dissatisfaction with teaching? Are they leaving because of the conditions of their work that shape their identity? Teacher identity work emphasises it is important beginning teachers understand their professional identity as something shifting, fluid and emerging – not fixed. These and other water metaphors – such as ‘washout’, ‘sink or swim’, and ‘thrown in the deep end’ – are often used to describe beginning teachers’ experiences. Such words and metaphors assist to portray the fluid and unpredictable nature of identity transformation. However, these survival terms also influence beginning teachers to believe that their transition to teaching will be difficult. Recently there has been an increased concern over beginning teacher attrition linked to the difficulties they encounter in their early years of teaching. Yet the conditions of beginning teachers’ work in Victorian schools in Australia – including the contractual nature of employment of first year (1yr) teachers – encourage these 1yr practitioners to view their work as semi-permanent. As a result these 1yr teachers do not see themselves as teaching for extended periods of time, as was once the case. Throughout 2011 twelve 1yr teachers shared their experiences of identity transformation in semi-structured interviews with the researcher. Their interview data was analysed through a theatre-based research method, examining how first experiences shape teachers’ future practice and identity. This presentation includes excerpts from the theatre-based research performance ‘The First Time’, and expands on the methodological approaches taken to analyse the data in a way that reflects the fluid and unpredictable nature of teachers’ identity formation and transformation. This qualitative study allows categories of description to emerge from the data rather than pre-determining categories of investigation. As such the processes of scripting, rehearsing, and performing, were utilised to analyse and re-present the data. In an aim to uncover questions that have been buried by answers, the research is oriented as a phenomenographic inquiry. This mode of inquiry seeks to describe, analyse, and understand the qualitatively different experiences 1yr teachers undergo in their identity formation and transformation. The results of this research reveal that beginning teachers’ identity transformation through their first experiences have both individual features specific to each teacher’s roles and aspirations, and extra-individual factors such as interactions, affiliations, and status, which shape their identity. Categories of description that have emerged from the analysis include survival, liminal, and hegemonic discourses, artifacts as symbols of belonging, and the impact of the contractual nature of teaching. Implications of this research focus on the importance for beginning teachers to develop an understanding of the transformative nature of identity in relation to the practice of teaching, to counter the negative preconceptions beginning teachers are told to expect as rites of passage upon entering the profession. The research outcomes have implications for teacher educators and in-service teachers negotiating the waters of an ever-changing profession.

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Teacher identity work emphasises it is important beginning teachers understand their professional identity as something shifting, fluid and emerging – not fixed. These and other water metaphors – such as ‘washout’, ‘sink or swim’, and ‘thrown in the deep end’ – are often used to describe beginning teachers’ experiences. Such words and metaphors portray the fluid and unpredictable nature of identity transformation, while also highlighting that beginning teachers in particular find this transformation difficult, resulting in high levels of teacher attrition in the early years.Throughout 2011 twelve beginning teachers shared their experiences of identity transformation in semi-structured interviews with the researcher. Their interview data was analysed and scripted into an ethnographic performance, examining how ‘first’ experiences shape teachers’ future practice and identity. This presentation includes excerpts from the performance ‘The First Time’, and expands on the methodological approaches taken to generate data and knowledge that reflects the fluid and unpredictable nature of teachers’ identity. This eclectic approach combined an understanding of the self (Mead, 1934) with non-naturalistic theatrical conventions used to form the data into an ethnographic performance. The research is framed within a practice theory approach (Schatzki, 2001) with a focus on practices situated within a particular time and place.The research findings focus on the importance of developing creativity and flexibility as key beginning teacher attributes in order to ‘swim with the current’, and to counter the negative preconceptions beginning teachers are told to expect as rites of passage upon entering the profession. The outcomes of my research have implications for teacher educators and in-service teachers in assisting beginning teachers to negotiate the waters of an ever-changing profession.

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Cross-flows (winds or currents) affect animal movements [1-3]. Animals can temporarily be carried off course or permanently carried away from their preferred habitat by drift depending on their own traveling speed in relation to that of the flow [1]. Animals able to only weakly fly or swim will be the most impacted (e.g., [4]). To circumvent this problem, animals must be able to detect the effects of flow on their movements and respond to it [1, 2]. Here, we show that a weakly swimming organism, the jellyfish Rhizostoma octopus, can orientate its movements with respect to currents and that this behavior is key to the maintenance of blooms and essential to reduce the probability of stranding. We combined insitu observations with first-time deployment of accelerometers on free-ranging jellyfish and simulated the behavior observed in wild jellyfish within a high-resolution hydrodynamic model. Our results show that jellyfish can actively swim countercurrent in response to current drift, leading to significant life-history benefits, i.e., increased chance of survival and facilitated bloom formation. Current-oriented swimming may be achieved by jellyfish either directly detecting current shear across their body surface [5] or indirectly assessing drift direction using other cues (e.g., magnetic, infrasound). Our coupled behavioral-hydrodynamic model provides new evidence that current-oriented swimming contributes to jellyfish being able to form aggregations of hundreds to millions of individuals for up to several months, which may have substantial ecosystem and socioeconomic consequences [6, 7]. It also contributes to improve predictions of jellyfish blooms' magnitude and movements in coastal waters. Current drift can have major and potentially negative effects on the lives of weakly swimming species in particular. Fossette etal. show that jellyfish modulate their swimming behavior in relation to current. Such oriented swimming has significant life-history benefits, such as increased bloom formation and a reduction of probability of stranding.

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Objectives: The Pictorial Scale of Perceived Movement Skill Competence (PMSC) assesses young children's perceptions of movement skill competence: 12 perceived Fundamental Movement skills (FMS; based on the Test of Gross Motor Development 2nd edition TGMD-2) and six Active Play activities (e.g. cycling). The main study purpose was to assess whether children's movement perception scores fit within the imposed constructs of Active Play and FMS by testing the latent structure and construct validity of the PMSC.

Design: Construct validation study.

Methods: Participants were part of the Melbourne Infant Feeding, Activity and Nutrition Trial (InFANT). The latent structure of the PMSC responses was tested through confirmatory factor analysis (CFA) and Bayesian Structural Equation Modeling (BSEM). Internal consistency was conducted using polychoric correlation-based alphas.

Results: The 303 children (boys 53.1%, n = 161) were aged 4-5 years (M = 4.7, SD = 0.46). The final model had an 18 item 3-factor solution with good fit indices (using CFA and BSEM). Factors were: Active Play (Bike, Board Paddle, Climb, Skate/Blade, Scooter, and Swim), Object Control - Hand Skills (Bounce, Catch, Hit, Throw), and FMS skills with a leg action (Gallop, Hop, Jump, Leap, Run, Step Slide, Kick, Roll). Alpha reliability values were: Active Play (0.78), Object Control-Hand Skills (0.76) and FMS-Dynamic Leg (0.84).

Conclusion: Young children can distinguish between movement perceptions. The factors reflect the hypothesized structure in terms of FMS being distinguished from Active Play. Further research should investigate how and if these constructs change in children over time.

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© 2015 Elsevier B.V. Ketamine, N-methyl- d-aspartate (NMDA) receptor antagonist and anti-inflammatory agent, has rapid therapeutic effects in a subset of patients with more intractable forms of depression. Irregular proinflammatory cytokine and acute-reactive protein levels have been reported in clinical and preclinical depression research. We explored the association between the rapid antidepressant-like effects of ketamine and peripheral proinflammatory profile in a model of antidepressant-resistance. Male Wistar rats were pre-treated with ACTH-(1-24) 100. μg/d or saline (0.9%) for 14. d. Antidepressant-like effects were assessed with the forced swim test (FST). Ketamine (10. mg/kg) significantly reduced immobility duration in saline-pretreated control animals. In contrast, a divergent response was observed in ACTH-pretreated antidepressant resistant animals, with 50% responders and 50% non-responders. Plasma samples were analyzed via enzyme-linked immunosorbent assay (ELISA) for interleukin 6 (IL-6), tumour necrosis factor alpha (TNFα) and C-reactive protein (CRP). Levels of CRP and TNFα differentiated ketamine responders and non-responders.

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This work was carried out to verify the effect of a glyphosate-based herbicide on Jundia hormones (cortisol, 17 beta-estradiol and testosterone), oocyte and swim-up fry production. Earthen ponds containing Jundia females were contaminated with glyphosate (3.6 mg/L); blood samples were collected from eight females from each treatment immediately before, or at 1, 10, 20 30 and 40 days following contamination. A typical post-stress rise in cortisol levels was observed at the 20th and 40th days following exposure to glyphosate. At the 40th day, 17 beta-estradiol was decreased in the exposed females. A similar number of oocytes were stripped out from females from both groups, however, a lower number of viable swim-up fry were obtained from the herbicide exposed females, which also had a higher liver-somatic index (LSI). The results indicate that the presence of glyphosate in water was deleterious to Rhamdia quelen reproduction, altering steroid profiles and egg viability. (c) 2006 Elsevier B.V. All rights reserved.

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This work presents the structure and ultrastructure of the interrenal gland and chromaffin cells, as well as the morphology of the head kidney of Brycon cephalus, the head kidney is composed of fused bilateral lobes located anterior to the swim bladder and ventrolateral to the spinal column, the parenchyma revealed lympho-haematopoietic tissue, melano-macrophage centres, interrenal gland and chromaffin cells. The interrenal gland consisted of cords or strands of cells grouped around the posterior cardinal vein and their branches. Chromaffin cells are found in small groups, closely associated with the interrenal gland and/or under the endothelium of the posterior cardinal vein. So far, the ultrastructural analysis has revealed only one interrenal cell type which contained abundant smooth endoplasmic reticulum and numerous mitochondria with tubulo-vesicular cristae, characteristic of steroid-producing cells. Two types of chromaffin cells were observed. The first type was characterized by the presence of vesicles with round, strongly electron-dense granules, which were eccentrically located, Such cells were interpreted as noradrenaline cells, Meanwhile, cells which contained smaller vesicles and electron-lucent granules, with a small halo separating the granule from the vesicular limiting membrane, were identified as adrenaline cells.

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The inflammatory response and hernatological parameters among Nile tilapia (Oreochromis niloticus) supplemented with Saccharomyces cerevisiae were evaluated six and 24 h after inoculation with inactivated Aeromonas hydrophila into the swim bladder. Six groups were formed (n = 10 each): G1 was treated with non-supplemented feed+injection with 0.65% saline solution; G2 with non-supplemented feed+ inoculation with A. hydrophila: G3 with feed containing 2% yeast+ injection with saline; G4 with feed containing 2% yeast + inoculation with A. hydrophila: G5 with feed containing 0.3% cell wall + injection with saline: and G6 with feed containing 0.3% cell wall + inoculation with A. hydrophila. In the groups inoculated with bacteria, the responses were more intense (P<0.05) than in those injected with saline. The groups receiving supplement that were inoculated with A. hydrophila accumulated a greater total number of cells at the lesion site (P<0.05) than did the non-supplemented groups, after six and 24 h. The groups receiving cell wall presented greater total accumulation of cells (P<0.005) that did those receiving yeast. The differential count showed that there were significantly greater number of thrombocytes (P< 0.05) and lower number of neutrophils, macrophages and lymphocytes (P<0.05) in the groups that received supplement, after 6 and 24 h, in relation to the non-supplemented groups. The values in the erythrocyte count, hemoglobin concentration and blood measurement indices did not differ statistically. The variation in circulating thrombocyte and leukocyte counts suggests that the inflammatory stimulus caused recruitment from reserve compartments to the blood. The groups that received yeast or yeast cell wall supplements presented increased nonspecific acute inflammatory response, thus suggesting that this has a beneficial effect on the immunological defense system. Published by Elsevier B.V.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The jeju is a teleost fish with bimodal respiration that utilizes a modified swim bladder as an air-breathing organ (ABO). Like all air-breathing fish studied to date, jeju exhibit pronounced changes in heart rate (f(H)) during air-breathing events, and it is believed that these may facilitate oxygen uptake (M-O2) from the ABO. The current study employed power spectral analysis (PSA) of f(H) patterns, coupled with instantaneous respirometry, to investigate the autonomic control of these phenomena and their functional significance for the efficacy of air breathing. The jeju obtained less than 5% of total M-O2 (M-tO2) from air breathing in normoxia at 26 degrees C, and PSA of beat-to-beat variability in fH revealed a pattern similar to that of unimodal water-breathing fish. In deep aquatic hypoxia (water P-O2=1 kPa) the jeju increased the frequency of air breathing (f(AB)) tenfold and maintained M-tO2 unchanged from normoxia. This was associated with a significant increase in heart rate variability (HRV), each air breath (AB) being preceded by a brief bradycardia and then followed by a brief tachycardia. These f(H) changes are qualitatively similar to those associated with breathing in unimodal air-breathing vertebrates. Within 20 heartbeats after the AB, however, a beat-to-beat variability in f(H) typical of water-breathing fish was re-established. Pharmacological blockade revealed that both adrenergic and cholinergic tone increased simultaneously prior to each AB, and then decreased after it. However, modulation of inhibitory cholinergic tone was responsible for the major proportion of HRV, including the precise beat-to-beat modulation of f(H) around each AB. Pharmacological blockade of all variations in f(H) associated with air breathing in deep hypoxia did not, however, have a significant effect upon f(AB) or the regulation of M-tO2. Thus, the functional significance of the profound HRV during air breathing remains a mystery.