Stressor categorization : acute physical and psychological stressors elicit distinctive recruitment patterns in the amygdala and in medullary noradrenergic cell groups

It has been hypothesized that the brain categorizes stressors and utilizes neural response pathways that vary in accordance with the assigned category. If this is true, stressors should elicit patterns of neuronal activation within the brain that are category-specific. Data from previous immediate–early gene expression mapping studies have hinted that this is the case, but interstudy differences in methodology render conclusions tenuous. In the present study, immunolabelling for the expression of c-fos was used as a marker of neuronal activity elicited in the rat brain by haemorrhage, immune challenge, noise, restraint and forced swim. All stressors elicited c-fos expression in 25–30% of hypothalamic paraventricular nucleus corticotrophin-releasing-factor cells, suggesting that these stimuli were of comparable strength, at least with regard to their ability to activate the hypothalamic–pituitary–adrenal axis. In the amygdala, haemorrhage and immune challenge both elicited c-fos expression in a large number of neurons in the central nucleus of the amygdala, whereas noise, restraint and forced swim primarily elicited recruitment of cells within the medial nucleus of the amygdala. In the medulla, all stressors recruited similar numbers of noradrenergic (A1 and A2) and adrenergic (C1 and C2) cells. However, haemorrhage and immune challenge elicited c-fos expression in subpopulations of A1 and A2 noradrenergic cells that were significantly more rostral than those recruited by noise, restraint or forced swim. The present data support the suggestion that the brain recognizes at least two major categories of stressor, which we have referred to as ‘physical’ and ‘psychological’. Moreover, the present data suggest that the neural activation footprint that is left in the brain by stressors can be used to determine the category to which they have been assigned by the brain.

An investigation into the use of physical modelling for the prediction of various feature types visible from different view points

This paper describes a general purpose flexible technique which uses physical modelling techniques for determining the features of a 3D object that are visible from any predefined view. Physical modelling techniques are used to determine which of many different types of features are visible from a complete set of viewpoints. The power of this technique lies in its ability to detect and parameterise object features, regardless of object complexity. Raytracing is used to simulate the physical process by which object features are visible so that surface properties (eg specularity, transparency) as well as object boundaries can be used in the recognition process. Using this technique occluding and non-occluding edge based features are extracted using image processing techniques and then parameterised. Features caused by specularity are also extracted and qualitative descriptions for these are defined.

Stereotypes and self-perceptions of physical education pre-service teachers

Stereotypes and self-perceptions are important in understanding how people develop their self-knowledge and social identity, become members of groups, and view groups and their members. While we have some understanding of the stereotypical view of the physical education teacher, we currently have little knowledge of how physical education pre-service teachers (students studying a physical education degree) are stereotyped, and also if there is any relationship between these stereotypes and how physical education pre-service teachers perceive themselves. The purpose of this study was to examine the stereotypes and self-perceptions of physical education pre-service teachers. The aims were to describe how physical education pre-service teachers stereotype and perceive themselves, examine if there are differences in the stereotypes and self-perceptions between males and females, and to explore if there were relationships between what the physical education pre-service teachers believed stereotyped them and how they perceived themselves. Participants were 250 students (n=120 males, n=130 female) studying a 4-year Bachelor of Education (Physical Education) degree at a university who completed a questionnaire which contained 10 items about how they viewed physical education pre-service teachers (stereotypes), and 26 items on how they viewed male physical education pre-service teachers and female pre-service teachers (stereotypes) and 26 items on how they view themselves (self-perceptions). Factor analysis revealed 2 stereotype factors, which were labelled as Sociable (e.g., socialise, partying, drinking, loud and outgoing) and Health and Lifestyle (e.g., fit, playing sport and not smoking). The stereotype of the male physical education pre-service teacher, comprised two factors: physical, assertive and aggressive behaviour (e.g., aggressive, dominant, self-confident, and competitive) and physical and self-presentation factors (muscular, athletic, physically fit, physically coordinated, and attractive). The stereotype of female physical education pre-service teachers comprised three factors: physical appearance and ability (e.g., physically fit, athletic, able-bodied, attractive, thin, and physically coordinated), aggressive and assertive behavioural style (e.g., intimidating, unapproachable, and aggressive), and masculine behavioural style (e.g., aggressive, masculine, feminine, muscular and dominant). The self-perception of male physical education pre-service teachers comprised three factors: perceived appearance and ability (e.g., athletic, physical fit, thin, attractive, muscular and pleased with their body), aggressive and confident behaviour (e.g., intimidating, dominant, show off and aggressive) and independence and intellect (e.g., independent, ambitious, self confident and intelligent). The self-perception of female physical education pre-service teachers comprised three factors: strong willed behaviour (e.g., ambitious, and dominant), presentation and appearance (e.g., pleased with their body, attractive, thin and self confident), and aggressive and dominant behaviour (e.g., aggressive, intimidating, masculine and show off). There were significant relationships between the male physical and self-presentation stereotype factor stereotype and perceived appearance and ability self-perception factor and between the male physical, assertive and aggressive behaviour stereotype factor and the male aggressive and confident behaviours self-perception factor. For females, the aggressive and dominant behaviour stereotype was related to both the aggressive and assertive behavioural style self-perception factor and the masculine behavioural style self-perception factor. It is suggested that future studies investigate the stereotypes and self-perceptions of students in schools during the recruitment phase of socialisation, and the possible influence of the physical education teacher education programme, faculty leaders, and significant others on the physical education pre-service teachers’ self-perceptions, stereotypes and socialisation into physical education.

Am I able? Is it worth it? Adolescent girls' motivational predispositions to school physical education : Associations with health-enhancing physical activity

The study purpose was to investigate predictive associations between adolescent girls’ motivational predispositions to physical education (PE) and habitual physical activity. Two hundred girls (age 13.1 ± 0.6 years) completed the Physical Education Predisposition Scale and the Physical Activity Questionnaire for Older Children. ANCOVAs revealed that girls with the highest Perceived PE Worth and Perceived PE Ability scores were the most habitually active groups (p < .0001). Significant predictors of physical activity identified by hierarchical regression were Perceived PE Ability and body mass index, which accounted for 17% and 3% of variance, respectively. As Perceived PE Ability was strongly associated with physical activity, the correlates of this construct should be further established to inform future school and PE-based interventions.

Increasing children’s physical activity : individual, social, and environmental factors associated with walking to and from school

Background. Efforts to increase the prevalence of children’s active school transport require evidence to inform the development of comprehensive interventions. This study used a multilevel ecological framework to investigate individual, social, and environmental factors associated with walking to and from school among elementary school-aged children, stratified by gender.
Method. Boys aged 10 to 13 years (n = 617) and girls aged 9 to 13 years (n = 681) attending 25 Australian primary schools located in high or low walkable neighborhoods completed a 1-week travel diary and a parent/child questionnaire on travel habits and attitudes.
Results. Boys were more likely (odds ratio [OR] = 3.37; p < .05) to walk if their school neighborhood had high connectivity and low traffic and less likely to walk if they had to cross a busy road (OR = 0.49; p < .05). For girls, confidence in their ability to walk to or from school without an adult (OR = 2.03), school encouragement (OR = 2.43), scheduling commitments (OR = 0.41), and parent-perceived convenience of driving (OR = 0.24) were significantly associated (p < .05) with walking. Irrespective of gender and proximity to school, child-perceived convenience of walking (boys OR = 2.17 and girls OR = 1.84) and preference to walk to school (child perceived, boys OR = 5.57, girls OR = 1.84 and parent perceived, boys OR = 2.82, girls OR = 1.90) were consistently associated (p < .05) with walking to and from school.
Conclusion. Although there are gender differences in factors influencing children walking to and from school, proximity to school, the safety of the route, and family time constraints are consistent correlates. These need to be addressed if more children are to be encouraged to walk to and from school.

Utilizing polypropylene fibers to improve physical and mechanical properties of concrete

The influence of polypropylene fibers has been studied in different proportioning and fiber aspect ratios to improve physical and mechanical properties of fiber-reinforced concretes. Fibers are used in two different lengths (12 mm and 19 mm) and proportions (0.1% and 0.3%) in concrete mixture design. Hardened concrete properties, such as 7- and 28-day compressive strength, splitting tensile strength, flexural strength, water and air absorption, and restrained shrinkage cracking were evaluated.

No statistically significant effects were observed for polypropylene fibers on the compressive strength of concrete, while toughness indexes, splitting tensile and flexural strength and durability parameters showed an increase in the presence of polypropylene fibers. Increased fiber availability (fiber aspect ratio) in the concrete matrix, in addition to the ability of longer polypropylene fibers to bridge on the micro cracks, are suggested as the reasons for the enhancement in mechanical properties. Finally, crack width in fiber-reinforced concrete is calculated analytically with fiber property variables (fiber type, length, diameter and proportion). Results are compared with experimental values and concluded that with an increase in fiber length and/or decrease in fiber diameter crack width, decrease significantly.

Children's physical activity and screen time : qualitative comparison of views of parents of infants and preschool children

Background
While parents are central to the development of behaviours in their young children, little is known about how parents view their role in shaping physical activity and screen time behaviours.

Methods
Using an unstructured focus group design, parental views and practices around children′s physical activity and screen time (television and computer use) were explored with eight groups of new parents (n=61; child age <12 months) and eight groups of parents with preschool-aged (3–5 year old) children (n=36) in Melbourne, Australia.

Results
Parents generally believed children are naturally active, which may preclude their engagement in strategies designed to increase physical activity. While parents across both age groups shared many overarching views concerning parenting for children′s physical activity and screen time behaviours, some strategies and barriers differed depending on the age of the child. While most new parents were optimistic about their ability to positively influence their child′s behaviours, many parents of preschool-aged children seemed more resigned to strategies that worked for them, even when aware such strategies may not be ideal.

Conclusions
Interventions aiming to increase children′s physical activity and decrease screen time may need to tailor strategies to the age group of the child and address parents′ misconceptions and barriers to optimum parenting in these domains.

Adolescents' perception of the relationship between movement skills, physical activity and sport

Movement skill competence is important to organised youth physical activity participation, but it is unclear how adolescents view this relationship. The primary aim of this study was to explore adolescents’ perception of the relationship between movement skills, physical activity and sport, and whether their perceptions differed according to extent of participation in organised physical activities. We recruited 33 (17 male) Grade 11 and 12 students (aged 16 to 18) from two secondary schools in Australia. Focus groups were allocated according to whether or not students participated in organised physical activity, where ‘organised activity’ was defined as activity which involved regular classes, training or competition, was reasonably structured or formal, or had a teacher, instructor or coach. There were three all-male ‘organised’ groups, one mixed-gender ‘organised’ group and one all-female ‘not-organised’ group. Students were asked about their attitudes towards physical activity and sport, the relationship between childhood skill proficiency and later physical activity and their perceptions of the appropriate time taken to learn movement skills. Group discussions lasted for approximately 50 minutes, were recorded and were then transcribed verbatim. Transcripts were read using a constant comparison method, in which quotes were continually compared to other quotes. A thematic analysis was conducted in which the transcripts were analysed inductively. Participation in organised sport had no bearing on opinions regarding whether lack of childhood skill development would negatively impact latter participation. It did, however, subtly influence opinions regarding whether skill could be successfully acquired later in life. When asked whether not having well-developed skills as a child would negatively impact on participation in sport/physical activity later in life, the response was mixed, but this was not related to their involvement in organised sport or activities. Students who believed early skill proficiency related to subsequent activity thought this was due to skill ability and motivation. An alternate view was that subsequent activity did not need to be based on skill proficiency; also, one’s environment might change, resulting in differing opportunities/constraints. Students felt skills could be learnt at any time in life (dependent on motivation), but that learning skills at a younger age would be easier and that skills learnt later would not be as developed. Fear of failure was identified as a barrier to learning when older. We conclude that motivation towards participation in sport and physical activity is affected by adolescents’ perception of their own movement skill ability. Therefore, developing children’s actual and perceived movement skills may help to increase adolescent physical activity. Since those with intrinsic achievement orientations were not as inclined towards organised activity, we may also need to provide physical activity options that resonate with intrinsic achievement motivations.

Protocol for a home-based integrated physical therapy program to reduce falls and improve mobility in people with Parkinson’s disease

Background The high incidence of falls associated with Parkinson’s disease (PD) increases the risk of injuries and immobility and compromises quality of life. Although falls education and strengthening programs have shown some benefit in healthy older people, the ability of physical therapy interventions in home settings to reduce falls and improve mobility in people with Parkinson’s has not been convincingly demonstrated.
Methods/design 180 community living people with PD will be randomly allocated to receive either a home-based integrated rehabilitation program (progressive resistance strength training, movement strategy training and falls education) or a home-based life skills program (control intervention). Both programs comprise one hour of treatment and one hour of structured homework per week over six weeks of home therapy. Blinded assessments occurring before therapy commences, the week after completion of therapy and 12 months following intervention will establish both the immediate and long-term benefits of home-based rehabilitation. The number of falls, number of repeat falls, falls rate and time to first fall will be the primary measures used to quantify outcome. The economic costs associated with injurious falls, and the costs of running the integrated rehabilitation program from a health system perspective will be established. The effects of intervention on motor and global disability and on quality of life will also be examined.
Discussion This study will provide new evidence on the outcomes and cost effectiveness of home-based movement rehabilitation programs for people living with PD.

Investigating the predictive ability of gait speed and quadriceps strength for incident falls in community-dwelling older women at high risk of fracture

Gait speed is a recommended geriatric assessment of physical performance, but may not be regularly examined in clinical settings. We aimed to investigate whether quadriceps strength tests demonstrate similar predictive ability for incident falls as gait speed in older women. We investigated 135 female volunteers aged mean±SD 76.7±5.0 years (range 70-92) at high risk of fracture. Participants completed gait speed assessments using the GAITRite Electronic Walkway System, and quadriceps strength assessments using a hand-held dynamometer (HHD). Participants reported incident falls monthly for 3.7±1.2 years. N=99 (73%) participants fell 355 times during the follow-up period (mean fall rate 83 per 100 person years). We observed a reduced odds ratio for multiple falls (0.83, 95% CI 0.70-0.98) and a reduced hazard ratio for time to first fall (0.90, 95% CI 0.83-0.98), according to quadriceps strength. There was also a significantly shorter time to first fall for those with low quadriceps strength (<7.0 kg; lowest tertile) compared with those with normal quadriceps strength (estimated means [95% CI] 1.54 [1.02, 2.06] vs. 2.23 [1.82, 2.64] years; P=0.019), but not for those with low (<1.0 m/s) vs. normal gait speed (P=0.15). Quadriceps strength is a significant predictor of incident falls over three years amongst community-dwelling older women at high risk of fracture. Quadriceps strength tests may be an acceptable alternative to gait speed for geriatric assessments of falls risk.

Fighting fires and fatigue: sleep, physical activity, and physical task performance

 During bushfires, firefighters often work long shifts with little sleep. Grace’s research showed that although firefighters’ sleep is restricted, it does not adversely affect their ability to perform physical tasks. This contrasts the cognitive impairments associated with sleep loss and could prompt revision of fatigue management guidelines in physically-demanding occupations.

Fatigue is a major issue for children and adolescents with physical disabilities

AIM: This study aimed to investigate fatigue, and its correlates, in children and adolescents with physical disabilities. METHOD: Sixty-five young people aged 8 to 17 years (35 males, 30 females; mean age 13y 2mo, SD 2y 8mo) with mild to moderate physical disabilities (Gillette Functional Assessment Questionnaire levels 7-10) were recruited. Self-reported fatigue was measured using the PedsQL Multidimensional Fatigue Scale. Physical activity was measured using 7-day hip-worn accelerometer. Associations between fatigue, physical activity, and socio-demographic characteristics were examined using analysis of covariance, with significance (α) set at 0.05. Results were compared with normative data from other paediatric populations. RESULTS: Among children with physical disabilities, fatigue was associated with being physically inactive (F-statistic=4.42, p=0.040), female (F=4.37, p=0.042), and of low socio-economic status (F=3.94, p=0.050). Fatigue was not associated with age, weight status, or functional impairment. Young people with physical disabilities experienced high levels of fatigue compared with other paediatric health populations, and comparable to the paediatric cancer population. INTERPRETATION: Fatigue is an important issue for young people with physical disabilities. Clinicians and researchers working with this group should be mindful that fatigue is likely to impact on an individual's ability to undertake new treatment regimens or interventions. Interventions aimed at reducing fatigue are warranted. Increasing physical activity might play a role in reducing fatigue.

Smartphone apps to improve fitness and increase physical activity among young people: protocol of the Apps for IMproving FITness (AIMFIT) randomized controlled trial

BACKGROUND: Physical activity is a modifiable behavior related to many preventable non-communicable diseases. There is an age-related decline in physical activity levels in young people, which tracks into adulthood. Common interactive technologies such as smartphones, particularly employing immersive features, may enhance the appeal and delivery of interventions to increase levels of physical activity in young people. The primary aim of the Apps for IMproving FITness (AIMFIT) trial is to evaluate the effectiveness of two popular "off-the-shelf" smartphone apps for improving cardiorespiratory fitness in young people.

METHODS/DESIGN: A three-arm, parallel, randomized controlled trial will be conducted in Auckland, New Zealand. Fifty-one eligible young people aged 14-17 years will be randomized to one of three conditions: 1) use of an immersive smartphone app, 2) use of a non-immersive app, or 3) usual behavior (control). Both smartphone apps consist of an eight-week training program designed to improve fitness and ability to run 5 km, however, the immersive app features a game-themed design and adds a narrative. Data are collected at baseline and 8 weeks. The primary outcome is cardiorespiratory fitness, assessed as time to complete the one mile run/walk test at 8 weeks. Secondary outcomes are physical activity levels, self-efficacy, enjoyment, psychological need satisfaction, and acceptability and usability of the apps. Analysis using intention to treat principles will be performed using regression models.

DISCUSSION: Despite the proliferation of commercially available smartphone applications, there is a dearth of empirical evidence to support their effectiveness on the targeted health behavior. This pragmatic study will determine the effectiveness of two popular "off-the-shelf" apps as a stand-alone instrument for improving fitness and physical activity among young people. Adherence to app use will not be closely controlled; however, random allocation of participants, a heterogeneous group, and data analysis using intention to treat principles provide internal and external validity to the study. The primary outcome will be objectively assessed with a valid and reliable field-based test, as well as the secondary outcome of physical activity, via accelerometry. If effective, such applications could be used alongside existing interventions to promote fitness and physical activity in this population. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry: ACTRN12613001030763. Registered 16 September 2013.

Modeling a system of phosphated cross-linked high amylose for controlled drug release. Part 2: Physical parameters, cross-linking degrees and drug delivery relationships

High amylose cross-linked to different degrees with sodium trimetaphosphate by varying base strength (2% or 4%) and contact time (0.5-4 h) was evaluated as non-compacted systems for sodium diclophenac controlled release. The physical properties and the performance of these products for sodium diclophenac controlled release from non-compacted systems were related to the structures generated at each cross-linking degree. For samples at 2% until 2 h the swelling ability, G' and eta* values increased with the cross-linking degree, because the longer polymer chains became progressively more entangled and linked. This increases water uptake and holding, favoring the swelling and resulting in systems with higher viscosities. Additionally, the increase of cross-linking degree should contribute for a more elastic structure. The shorter chains with more inter-linkages formed at higher cross-linking degrees (2%4h and 4%) make water caption and holding difficult, decreasing the swelling, viscosity and elasticity. For 2% samples, the longer drug release time exhibited for 2%4h sample indicates that the increase of swelling and viscosity contribute for a more sustained drug release, but the mesh size of the polymeric network seems to be determinant for the attachment of drug molecules. For the 4% samples, smaller meshes size should determine less sustained release of drug. (C) 2008 Elsevier B.V. All rights reserved.