734 resultados para Self-compacting concrete


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The mechanisms involved in alcohol use disorders are complex. It has been shown that ghrelin is an important signal for the control of body weight homeostasis, preferably by interacting with hypothalamic circuits, as well as for drug reward by activating the mesolimbic dopamine system. The ghrelin receptor (GHS-R1A) has been shown to be required for alcohol-induced reward. Additionally, ghrelin increases and GHR-R1A antagonists reduce moderate alcohol consumption in mice, and a single nucleotide polymorphism in the GHS-R1A gene has been associated with high alcohol consumption in humans. However, the role of central ghrelin signaling in high alcohol consumption is not known. Therefore, the role of GHS-R1A in operant self-administration of alcohol in rats as well as for high alcohol consumption in Long-Evans rats and in alcohol preferring [Alko alcohol (AA)] rats was studied here. In the present study, the GHS-R1A antagonist, JMV2959, was found to reduce the operant self-administration of alcohol in rats and to decrease high alcohol intake in Long-Evans rats as well as in AA rats. These results suggest that the ghrelin receptor signaling system, specifically GHS-R1A, is required for operant self-administration of alcohol and for high alcohol intake in rats. Therefore, the GHS-R1A may be a therapeutic target for treatment of addictive behaviors, such as alcohol dependence.

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This multidisciplinary research advanced the current understanding of self-regulation – a critical component in safe and sustainable mobility for older adults. It investigates the sociodemographic and psychosocial factors that underlies older adults' self-regulation, and examines their travel behaviours using a combination of self-report, in-vehicle and wearable devices. This research developed a novel theoretical model that significantly predicts self-regulation and objectively driving behaviours among older drivers.

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As a dance student, professional, teacher, or just a “normal” human being, self-esteem is something that can influence your level of confidence in undertaking tasks or how you feel about yourself generally — all of which can have a significant impact upon the results that you achieve...

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Production of recycled concrete aggregates (RCA) from construction and demolition (C&D) waste has become popular all over the world since the availability of land spaces are limited to dispose. Therefore it is important to seek alternative applications for RCA. The use of RCA in base and sub-base layers in granular pavement is a viable solution. In mechanistic pavement design, rutting (permanent deformation) is considered as the major failure mechanisms of the pavement. The rutting is the accumulation of permanent deformation of pavement layers caused by the repetitive vehicle load. In Queensland, Australia, it is accepted to have the maximum of 20% of reclaimed asphalt pavement (RAP) in RCA and therefore, it is important to investigate the effect of RAP on the permanent deformation properties of RCA. In this study, a series of repeated load triaxial (RLT) tests were conducted on RCA blended with different percentage of RAP to investigate the permanent deformation and resilient modulus properties of RCA. The vertical deformation and resilient modulus values were used to determine the response of RCA for the cyclic loading under standard pressure and loading conditions.

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Population increase and economic developments can lead to construction as well as demolition of infrastructures such as buildings, bridges, roads, etc resulting in used concrete as a primary waste product. Recycling of waste concrete to obtain the recycled concrete aggregates (RCA) for base and/or sub-base materials in road construction is a foremost application to be promoted to gain economical and sustainability benefits. As the mortar, bricks, glass and reclaimed asphalt pavement (RAP) present as constituents in RCA, it exhibits inconsistent properties and performance. In this study, six different types of RCA samples were subjected classification tests such as particle size distribution, plasticity, compaction test, unconfined compressive strength (UCS) and California bearing ratio (CBR) tests. Results were compared with those of the standard road materials used in Queensland, Australia. It was found that material type ‘RM1-100/RM3-0’ and ‘RM1-80/RM3-20’ samples are in the margin of the minimum required specifications of base materials used for high volume unbound granular roads while others are lower than that the minimum requirement.

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With a view to minimising the spiraling labour costs, the concrete masonry industry is developing thin layer mortar technology (known as thin bed technology) collaboratively with Queensland University of Technology. Similar technologies are practiced in Europe mainly for clay brick masonry; in the UK thin layer mortared concrete masonry has been researched under commercial contract with limited information published. This paper presents numerous experimental data generated over the past three years. It is shown that this form of masonry requires special drymixed mortar containing a minimum of 2% polymer for improved workability and blocks with tighter height tolerance, both of which might increase the cost of these constituent materials. However, through semiskilled labour, tools to dispense and control the thickness of mortar and the associated increase in productivity, reduction to the overall costs of this form of construction can be achieved. Further the polymer mortar provides several advantages: (1) improved sustainability due to dry curing and (2) potential to construct mortar layers of 2mm thickness and (3) ability for mechanisation of mortar application and control of thickness without the need for skilled labour.

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Bond characteristics of masonry are partly affected by the type of mortar used, the techniques of dispersion of mortar and the surface texture of the concrete blocks. Additionally it is understood from the studies on conventional masonry, the bond characteristics are influenced by masonry age and curing methods as well as dryness/dampness at the time of testing. However, all these effects on bond for thin bed masonry containing polymer cement mortar are not well researched. Therefore, the effect of ageing and curing method on bond strength of masonry made with polymer cement mortar was experimentally investigated as part of an ongoing bond strength research program on thin bed concrete masonry at Queensland University of technology. This paper presents the experimental investigation of the flexural and shears bond characteristics of thin bed concrete masonry of varying age/ curing methods. Since, the polymer cement mortar is commonly used in thin bed masonry; bond development through two different curing conditions (dry/wet) was investigated in this research work. The results exhibit that the bond strength increases with the age under the wet and dry curing conditions; dry curing produce stronger bond and is considered as an advantage towards making this form of thin bed masonry better sustainable.

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The aim of the current study was to examine the associations between a number of individual factors (demographic factors (age and gender), personality factors, risk-taking propensity, attitudes towards drink driving, and perceived legitimacy of drink driving enforcement) and how they influence the self-reported likelihood of drink driving. The second aim of this study was to examine the potential of attitudes mediating the relationship between risk-taking and self-reported likelihood of drink driving. In total, 293 Queensland drivers volunteered to participate in an online survey that assessed their self-reported likelihood to drink drive in the next month, demographics, traffic-related demographics, personality factors, risk-taking propensity, attitudes towards drink driving, and perceived legitimacy of drink driving enforcement. An ordered logistic regression analysis was utilised to evaluate the first aim of the study; at the first step the demographic variables were entered; at step two the personality and risk-taking were entered; at the third step, the attitudes and perceptions of legitimacy variables were entered. Being a younger driver and having a high risk-taking propensity were related to self-reported likelihood of drink driving. However, when the attitudes variable was entered, these individual factors were no longer significant; with attitudes being the most important predictor of self-reported drink driving likelihood. A significant mediation model was found with the second aim of the study, such that attitudes mediated the relationship between risk-taking and self-reported likelihood of drink driving. Considerable effort and resources are utilised by traffic authorities to reducing drink driving on the Australian road network. Notwithstanding these efforts, some participants still had some positive attitudes towards drink driving and reported that they were likely to drink drive in the future. These findings suggest that more work is needed to address attitudes regarding the dangerousness of drink driving.

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The Early Years Generalizing Project (EYGP) involves Australian years 1 to 4 (age 5 to 9) students and investigates how they grasp and express generalizations. This paper focuses on data collected from 6 Year 1 students in an exploratory study within a clinical interview setting that required students to identify function rules. Preliminary findings suggest that the use of gestures (both by students and interviewers), self-talk (by students), and concrete acting out, assisted students to reach generalizations and to begin to express these generalities. It also appears that as students became aware of the structure, their use of gestures and selftalk tended to decrease.

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Introduction Female sexual functioning is affected by a range of factors including motivation, psychological well-being, and relationship issues. In understanding female sexual dysfunction (FSD), there has been a tendency to privilege diagnostic and medical over relationship issues. Aim To investigate the association between women’s experience of intimacy in close relationships - operationalized in terms of attachment and degree of differentiation of self - and FSD. Methods Two hundred and thirty sexually active Australian women responded to an invitation to complete a set of validated scales to assess potential correlates of sexual functioning. Main Outcome Measures The Female Sexuality Function Index, the Experiences in Close Relationships Scale, the Differentiation of Self Inventory, as well as a set of study-specific questions were subject to hierarchical multiple regression analyses Results Relational variables of attachment avoidance and to a lesser degree, attachment anxiety were associated with FSD. Participants with lower levels of differentiation of self were more likely to report sexual difficulties. The inability to maintain a sense of self in the presence of intimate others was the strongest predictors of sexual problems. A history of sexual abuse in adulthood and higher levels of psychological distress were also associated with sexual difficulties. Conclusions The findings provide support for a relational understanding of female sexual functioning. Attachment avoidance, attachment anxiety, and degree of differentiation of self are shown to be associated with sexual difficulties. The findings support the need to focus on relational and psychological factors in women’s experience of sex.

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Research Findings The present study investigated whether active play during recess was associated with self-regulation and academic achievement in a prekindergarten sample. A total of 51 children in classes containing approximately half Head Start children were assessed on self-regulation, active play, and early academic achievement. Path analyses indicated that higher active play was associated with better self-regulation, which in turn was associated with higher scores on early reading and math assessments. Practice or Policy Results point to the benefits of active play for promoting self-regulation and offer insight into possible interventions designed to promote self-regulation and academic achievement.

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Self-regulation refers to our individual capacities to regulate our behaviours, emotions, and thoughts, with these skills developing rapidly across early childhood. This thesis examined sleep, emotional, and cognitive regulation development, and related parental influences, for children participating in the Longitudinal Study of Australian Children. Important longitudinal associations among children's self-regulation, maternal mental health, parenting, and later behaviour problems for children were also investigated. A unique contribution of this research was a prevalence estimate of early childhood self-regulation problems in Australian children that was documented for the first time.

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A cross-sectional survey of female office workers (n=333) was undertaken to determine the level of neck pain and disability (Neck Disability Index—NDI) and to explore the relationship between individual and workplace risk factors with the NDI score and the presence of pain. Workers reported nil (32%), mild (53%), moderate (14%) and severe (1%) neck pain. There were more risk factors associated with the NDI score than the presence of neck pain. The presence of neck pain was associated with a history of neck trauma (OR: 4.8), using a graduated lens (OR: 4.6), and negative affectivity (OR: 2.7) in the multiple regression model. Factors associated with higher NDI score were using the computer mouse for more than 6 h per day, higher negative affectivity, older age and an uncomfortable workstation. These results suggest that measuring the level of neck pain and disability rather than just the presence of neck pain provides more specific directives for the prevention and management of this disorder.

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This study explored the interaction between physical and psychosocial factors in the workplace on neck pain and disability in female computer users. A self-report survey was used to collect data on physical risk factors (monitor location, duration of time spent using the keyboard and mouse) and psychosocial domains (as assessed by the Job Content Questionnaire). The neck disability index was the outcome measure. Interactions among the physical and psychosocial factors were examined in analysis of covariance. High supervisor support, decision authority and skill discretion protect against the negative impact of (1) time spent on computer-based tasks, (2) non-optimal placement of the computer monitor, and; (3) long duration of mouse use. Office workers with greater neck pain experience a combination of high physical and low psychosocial stressors at work. Prevention and intervention strategies that target both sets of risk factors are likely to be more successful than single intervention programmes. Statement of Relevance The results of this study demonstrate that the interaction of physical and psychosocial factors in the workplace has a stronger association with neck pain and disability than the presence of either factor alone. This finding has important implications for strategies aimed at the prevention of musculoskeletal problems in office workers.

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Does job control act as a stress-buffer when employees' type and level of work self-determination is taken into account? It was anticipated that job control would only be stress-buffering for employees high in self-determined and low in non-self-determined work motivation. In contrast, job control would be stress-exacerbating for employees who were low in self-determined and high in non-self-determined work motivation. Employees of a health insurance organization (N = 123) completed a survey on perceptions of role overload, job control, work self-determination, and a range of strain and engagement indicators. Results revealed that, when individuals high in self-determination perceived high job control, they experienced greater engagement (in the form of dedication to their work). In addition, when individuals high in non-self-determination perceived high job demands, they experienced more health complaints. A significant 3-way interaction demonstrated that, for individuals low in non-self-determination, high job control had the anticipated stress-buffering effect on engagement (in the form of absorption in their work). In addition, low job control was stress-exacerbating. However, contrary to expectations, for those high in non-self-determination, high job control was just as useful as low job control as a stress-buffer. The practical applications of these findings to the organizational context are discussed.