995 resultados para Adaptation, Biological.


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A bioactive and bioresorbable scaffold fabricated from medical grade poly (epsilon-caprolactone) and incorporating 20% beta-tricalcium phosphate (mPCLTCP) was recently developed for bone regeneration at load bearing sites. In the present study, we aimed to evaluate bone ingrowth into mPCLTCP in a large animal model of lumbar interbody fusion. Six pigs underwent a 2-level (L3/4; L5/6) anterior lumbar interbody fusion (ALIF) implanted with mPCLTCP 0.6 mg rhBMP-2 as treatment group while four other pigs implanted with autogenous bone graft served as control. Computed tomographic scanning and histology revealed complete defect bridging in all (100%) specimen from the treatment group as early as 3 months. Histological evidence of continuing bone remodeling and maturation was observed at 6 months. In the control group, only partial bridging was observed at 3 months and only 50% of segments in this group showed complete defect bridging at 6 months. Furthermore, 25% of segments in the control group showed evidence of graft fracture, resorption and pseudoarthrosis. In contrast, no evidence of graft fractures, pseudoarthrosis or foreign body reaction was observed in the treatment group. These results reveal that mPCLTCP scaffolds could act as bone graft substitutes by providing a suitable environment for bone regeneration in a dynamic load bearing setting such as in a porcine model of interbody spine fusion.

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Aim To measure latitude-related body size variation in field-collected Paropsis atomaria Olivier (Coleoptera: Chrysomelidae) individuals and to conduct common-garden experiments to determine whether such variation is due to phenotypic plasticity or local adaptation. Location Four collection sites from the east coast of Australia were selected for our present field collections: Canberra (latitude 3519' S), Bangalow (latitude 2843' S), Beerburrum (latitude 2658' S) and Lowmead (latitude 2429' S). Museum specimens collected over the past 100 years and covering the same geographical area as the present field collections came from one state, one national and one private collection. Methods Body size (pronotum width) was measured for 118 field-collected beetles and 302 specimens from collections. We then reared larvae from the latitudinal extremes (Canberra and Lowmead) to determine whether the size cline was the result of phenotypic plasticity or evolved differences (= local adaptation) between sites. Results Beetles decreased in size with increasing latitude, representing a converse Bergmann cline. A decrease in developmental temperature produced larger adults for both Lowmead (low latitude) and Canberra (high latitude) individuals, and those from Lowmead were larger than those from Canberra when reared under identical conditions. Main conclusions The converse Bergmann cline in P. atomaria is likely to be the result of local adaptation to season length.

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Examined the social adaptation of 32 children in grades 36 with mild intellectual disability: 13 Ss were partially integrated into regular primary school classes and 19 Ss were full-time in separate classes. Sociometric status was assessed using best friend and play rating measures. Consistent with previous research, children with intellectual disability were less socially accepted than were a matched group of 32 children with no learning disabilities. Children in partially integrated classes received more play nominations than those in separate classes, but had no greater acceptance as a best friend. On teachers' reports, disabled children had higher levels of inappropriate social behaviours, but there was no significant difference in appropriate behaviours. Self-assessments by integrated children were more negative than those by children in separate classes, and their peer-relationship satisfaction was lower. Ratings by disabled children of their satisfaction with peer relationships were associated with ratings of appropriate social skills by themselves and their teachers, and with self-ratings of negative behaviour. The study confirmed that partial integration can have negative consequences for children with an intellectual disability.

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The use of the PC and Internet for placing telephone calls will present new opportunities to capture vast amounts of un-transcribed speech for a particular speaker. This paper investigates how to best exploit this data for speaker-dependent speech recognition. Supervised and unsupervised experiments in acoustic model and language model adaptation are presented. Using one hour of automatically transcribed speech per speaker with a word error rate of 36.0%, unsupervised adaptation resulted in an absolute gain of 6.3%, equivalent to 70% of the gain from the supervised case, with additional adaptation data likely to yield further improvements. LM adaptation experiments suggested that although there seems to be a small degree of speaker idiolect, adaptation to the speaker alone, without considering the topic of the conversation, is in itself unlikely to improve transcription accuracy.

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The term self-selected (i.e., individual or comfortable walking pace or speed) is commonly used in the literature (Frost, Dowling, Bar-Or, & Dyson, 1997; Jeng, Liao, Lai, & Hou, 1997; Wergel-Kolmert & Wohlfart, 1999; Maltais, Bar-Or, Pienynowski, & Galea, 2003; Browning & Kram, 2005; Browning, Baker, Herron, & Kram, 2006; Hills, Byrne, Wearing, & Armstrong, 2006) and is identified as the most efficient walking speed, with increased efficiency defined by lower oxygen uptake (VO^sub 2^) per unit mechanical work (Hoyt & Taylor, 1981; Taylor, Heglund, & Maloiy, 1982; Hreljac, 1993). [...] assessing individual and group differences in metabolic energy expenditure using oxygen uptake requires individuals to be comfortable with, and able to accommodate to, the equipment.

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Although placing reflective markers on pedestrians major joints can make pedestrians more conspicuous to drivers at night, it has been suggested that this biological motion effect may be reduced when visual clutter is present. We tested whether extraneous points of light affected the ability of 12 younger and 12 older drivers to see pedestrians as they drove on a closed road at night. Pedestrians wore black clothing alone or with retroreflective markings in four different configurations. One pedestrian walked in place and was surrounded by clutter on half of the trials. Another was always surrounded by visual clutter but either walked in place or stood still. Clothing configuration, pedestrian motion, and driver age influenced conspicuity but clutter did not. The results confirm that even in the presence of visual clutter pedestrians wearing biological motion configurations are recognized more often and at greater distances than when they wear a reflective vest.

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Global warming can have a significant impact on the building thermal environment and energy performance. Because greenhouse gas concentrations are still continuing to increase, this warming process will continue and may accelerate. Adaptation to global warming is therefore emerging as one of the key requirements for buildings. This requires all the existing and new buildings not only to perform and operate satisfactorily in the new environment but also to satisfy the environmental performance criteria of sustainability. Through a parametric study using the building simulation technique, this paper investigates the adaptation potential of changing the building internal load densities to the future global warming. Case studies for office buildings in major Australian capital cities are presented. Based on the results of parametric study, possible adaptation strategies are also proposed and evaluated.

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This thesis critically analyses sperm donation practices from a child-centred perspective. It examines the effects, both personal and social, of disrupting the unity of biological and social relatedness in families affected by donor conception. It examines how disruption is facilitated by a process of mediation which is detailed using a model provided by Sunderland (2002). This model identifies mediating movements - alienation, translation, re-contextualisation and absorption - which help to explain the powerful and dominating material, and social and political processes which occur in biotechnology, or in reproductive technology in this case. The understanding of such movements and mediation of meanings is inspired by the complementary work of Silverstone (1999) and Sunderland. This model allows for a more critical appreciation of the movement of meaning from previously inalienable aspects of life to alienable products through biotechnology (Sunderland, 2002). Once this mediation in donor conception is subjected to critical examination here, it is then approached from different angles of investigation. The thesis posits that two conflicting notions of the self are being applied to fertility-frustrated adults and the offspring of reproductive interventions. Adults using reproductive interventions receive support to maximise their genetic continuity, but in so doing they create and dismiss the corresponding genetic discontinuity produced for the offspring. The offsprings kinship and identity are then framed through an experimental postmodernist notion, presenting them as social rather than innate constructs. The adults using the reproductive intervention, on the other hand, have their identity and kinship continuity framed and supported as normative, innate, and based on genetic connection. This use of shifting frameworks is presented as unjust and harmful, creating double standards and a corrosion of kinship values, connection and intelligibility between generations; indeed, it is put forward as adult-centric. The analysis of other forms of human kinship dislocation provided by this thesis explores an under-utilised resource which is used to counter the commonly held opinion that any disruption of social and genetic relatedness for donor offspring is insignificant. The experiences of adoption and the stolen generations are used to inform understanding of the personal and social effects of such kinship disruption and potential reunion for donor offspring. These examples, along with laws governing international human rights, further strengthen the appeal here for normative principles and protections based on collective knowledge and standards to be applied to children of reproductive technology. The thesis presents the argument that the framing and regulation of reproductive technology is excessively influenced by industry providers and users. The interests of these parties collide with and corrode any accurate assessments and protections afforded to the children of reproductive technology. The thesis seeks to counter such encroachments and concludes by presenting these protections, frameworks, and human experiences as resources which can help to address the problems created for the offspring of such reproductive interventions, thereby illustrating why these reproductive interventions should be discontinued.

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The present study investigates the experiences of Sudanese refugees by exploring the themes that characterise participants experiences in Sudan, en route, and at their Australian destination. In particular, the research identifies several factors that may be seen as helps or hindrances to Sudanese refugees adaptation. Participants were 12 Sudanese refugees aged between 19 and 40 years who had been residing in Australia for five years or less. A qualitative phenomenological approach to data collection and analysis was employed. Examination of the interview transcripts revealed that all participants identified both hindrances and helps toward adaptation and indicated that positive adaptation is not only possible, but probable for Sudanese refugees in spite of their past experiences of trauma and present resettlement difficulties. Several practical implications were elicited from the research including a need for programs that actively promote refugees adaptation by encouraging the broadening of social networks.