Influence of growth rate on the immature skeleton

Bone architecture adapts to withstand the loads placed upon it. In response to increased loads during growth, bones circumferentially expand to increase their diameter through the incorporation of periosteal blood vessels and the formation and infilling of primary osteons. However, the influence of growth rate on bone architecture in the immature skeleton is not fully understood. To investigate how bone architecture is modulated by growth rate, morphometric, biochemical and genetic comparisons were made between tibiae from broiler chickens with either fast or slow growth potentials. Both strains of chickens were kept under identical conditions, and fed ad-libitum standard broiler feed. Tibiae were removed and tested by three-point bending to determine stiffness and breaking strength and cross sections of the tibia were examined histomorphologically. Bone stiffness and breaking strength were higher in the rapidly growing birds, but after adjustment for body weight the bones were inherently weaker. Cortical porosity periosteally, but not endosteally, was increased. Sections reacted for ALP and TRAP activity, and others stained for cement (reversal) lines indicated the absence of primary osteon remodelling in the periosteal region. This suggests that the increased periosteal porosity is due to slower infilling of the primary osteons in the rapidly growing birds. To directly quantify the rate of osteon infilling, tibiae were removed from 21-day-old chicks, which had been double labelled with calcein (80 and 8 h before death). The mineral apposition rate was higher in the slow growing chickens, and confirmined the previous histomorphometry results. Osteocyte density within the circumferential lamellae of the cortical bone was higher in the rapidly growing birds but unchanged within the newly laid down bone of the primary osteons. Immunohistochemical staining of cortical bone sections from chickens injected with bromodeoxyuridine located proliferating pre-osteoblast cells to the osteogenic layer of the periosteum. A lower labelling index in the rapidly growing birds was seen across four circumferential areas of the periosteum (anterior = fast growing area, posterior = slow growing area, medial and lateral = intermediate growing areas), even though the osteogenic layer of the periosteum was thicker in the fast strain. Blood vessel numbers within the periosteum was similar between strains but differed between regions habitually loaded in tension (anterior) or in compression (posterior). Osteoblasts were grown and expanded in culture from explants of tibia cortical bone (periosteum removed) of 21-day-old birds of both strains (n=4/strain). Osteoblast proliferation was determined by tritiated-thymidine uptake and differentiation by alkaline phosphatase (ALP) activity. At pre-confluency, cell proliferation was higher in the slow growing birds, but this pattern was reversed at confluency and post confluency which was a likely consequence of impairment of proliferation by contact inhibition in the slow growing strain. ALP activity was only detected at post-confluency and was higher in the fast growing strain. Osteoblastic gene expression was determined by RT-PCR and quantified by densitometry. A higher level of osteopontin, and bone sialoprotein expression (BSP) was observed in the slow growing birds. Whereas Runx2 and the serotonin receptor, considered to have a role in mechanoregulation, were more highly expressed in the fast chickens. In conclusion, fast growth resulted in the expected circumferential expansion to increase bone bending strength. Fast growth was accompanied by increased porosity resulting from the rapid formation of primary osteons and the incapacity of osteoblasts to completely infill the resultant canal. However, periosteal interstitial bone of the fast growing birds had a higher osteocyte density suggesting that the lack of infilling was not due to a decrease in osteoblast number. No evidence was obtained to suggest that osteonal remodelling or periosteal blood vessel number were a determinant for primary osteon size. However, the lower labelling index at the periosteum and increased osteocyte density within the circumferential lamellae of the fast strain suggests an increase in transit time through the osteoblast lineage at the periosteal surface. In vitro, osteoblast proliferation was faster in the slow growing birds whereas differentiation was slower. This is in accord with the previous hypothesis that the fast growing birds are characterised by an increase in transit time through the osteoblast lineage, which may be driven by the high levels of Runx2 expression. Osteopontin and BSP are associated with mechanical loading but the significance of the lower expression levels in the fast growing birds requires further study. However, the up regulation of serotonin expression may reflect the greater loads experienced in the fast growing birds in vivo

Interacting with Presence. HCI and the Sense of Presence in Computer-mediated Environments

The experience of using and interacting with the newest Virtual Reality and computing technologies is profoundly affected by the extent to which we feel ourselves to be really ‘present’ in computer-generated and -mediated augmented worlds. This feeling of 'Presence’, of “being inside the mediated world”, is key to understanding developments in applications such as interactive entertainment, gaming, psychotherapy, education, scientific visualisation, sports training and rehabilitation, and many more. This edited volume, featuring contributions from internationally renowned scholars, provides a comprehensive introduction to and overview of the topic of mediated presence - or ‘tele-presence’ - and of the emerging field of presence research. It is intended for researchers and graduate students in human-computer interaction, cognitive science, psychology, cyberpsychology and computer science, as well as for experienced professionals from the ICT industry. The editors are all well-known professional researchers in the field: Professor Giuseppe Riva from the Catholic University of Milan, Italy; Professor John Waterworth from Umeå University, Sweden; Dianne Murray, an HCI Consultant and editor of the journal “Interacting with Computers”

A synopsis of the mental health concerns of university students: results of a text-based online survey from one Australian university

Within the university community, student demographic data highlights a high level of cultural diversity and an ‘at-risk’ population for the onset of mental health problems. Moreover, the transition to higher education is itself associated with a range of emotional, social and academic demands that can cause psychological distress. Therefore, at any one time, a substantial number of students may be attempting to complete university studies while managing problematic symptoms, behaviours or an emerging or diagnosed mental disorder. The aim of this paper is to provide a snapshot of these students' experiences to enable strategic planning of future university support services. Of particular importance was the identification of facilitators and barriers that this group of students faced while engaged in university life. Participants were 1378 students enrolled at a Western Australian university who accessed a text-based online survey during May 2009. The students provided descriptions of the range of problematic symptoms, behaviours and/or disorders that were causing interference with their lives, and university career. Not surprisingly, the most commonly identified disorders with the participant population were depression, anxiety and stress-related concerns. More than half the sample had not sought professional help. The results highlight the fact that universities are well placed to play a major role in improving pathways to primary care and early intervention for students with an emerging or diagnosed mental health problem and to identify and support students trying to manage the ‘normal’ psychological demands associated with higher education

“Teacher Burnout Is One of My Greatest Fears”: Interrupting a Narrative on Fire

Teacher burnout is often positioned as a common result of the complex demands of the teaching profession (García-Carmona et al., 2019). While there is no denying the demanding nature of teaching, in this article we present an alternative perspective on the widespread burnout discussion that distinguishes between burnout and the complexities of teacher attrition, and offer a more hopeful and strengths-based approach to the teaching profession. In a qualitative study that analyzed the anticipatory beliefs that pre-service teachers expressed in a reflective assignment for a course focused on Comprehensive School Health (CSH), we found evidence to suggest that the burnout narrative may threaten teacher candidates’ self-efficacy before entering the teaching profession. We call for a disruption to the overemphasis of burnout narratives in teacher education programs as they may undermine the profession.L’épuisement professionnel des enseignants est souvent perçu comme un résultat commun découlant des exigences complexes de la profession d’enseignant (Garcia-Carmona et al., 2019). Bien que la nature exigeante de l’enseignement soit indéniable, nous présentons dans cet article une perspective alternative sur la discussion générale concernant l’épuisement professionnel qui fait la distinction entre l’épuisement professionnel et les complexités de l’attrition des enseignants, et offre une approche plus optimiste et fondée sur les forces de la profession enseignante. Une étude qualitative a analysé les croyances anticipées exprimées par des enseignants en formation initiale. Dans un travail de réflexion effectué par ceux-ci dans le cadre d’un cours axé sur la santé scolaire globale, nous avons trouvé des preuves qui indiquent que le discours sur l’épuisement professionnel peut menacer l’autoefficacité des candidats avant même leur entrée dans la profession. Nous appelons à une cessation de la trop grande importance accordée aux récits d’épuisement professionnel dans les programmes de formation à l’enseignement puisqu’elle pourrait miner la profession

Counselors' Attributions of Blame Toward Female Survivors of Battering

Intimate partner violence (IPV) is a social problem that affects roughly 5.3 million women in the U.S. each year, accounts for 1,300 deaths, and often results in a number of physical and mental health consequences. Many women seek counseling as a way to find relief from the symptoms of the abuse they have endured. Previous research indicates that women seeking counseling after facing intimate partner violence victimization have reported experiencing counseling resources as inadequate or blaming. In the current study, counselors (N = 122) were surveyed regarding their gender role attitudes, ambivalent sexism, training in family violence, and attributions of blame toward women who have been battered. The regression analysis suggested that 16% of the variance in blame attributions was accounted for by gender role attitudes and ambivalent sexism. Study findings provide directions for future research and implications for practicing counselors

During postnatal development endogenous neurosteroids influence GABA-ergic neurotransmission of mouse cortical neurons

AbstractAs neuronal development progresses, GABAergic synaptic transmission undergoes a defined program of reconfiguration. For example, GABAA receptor (GABAAR)-mediated synaptic currents, (miniature inhibitory postsynaptic currents; mIPSCs), which initially exhibit a relatively slow decay phase, become progressively reduced in duration, thereby supporting the temporal resolution required for mature network activity. Here we report that during postnatal development of cortical layer 2/3 pyramidal neurons, GABAAR-mediated phasic inhibition is influenced by a resident neurosteroid tone, which wanes in the second postnatal week, resulting in the brief phasic events characteristic of mature neuronal signalling. Treatment of cortical slices with the immediate precursor of 5α-pregnan-3α-ol-20-one (5α3α), the GABAAR-inactive 5α-dihydroprogesterone, (5α-DHP), greatly prolonged the mIPSCs of P20 pyramidal neurons, demonstrating these more mature neurons retain the capacity to synthesize GABAAR-active neurosteroids, but now lack the endogenous steroid substrate. Previously, such developmental plasticity of phasic inhibition was ascribed to the expression of synaptic GABAARs incorporating the α1 subunit. However, the duration of mIPSCs recorded from L2/3 cortical neurons derived from α1 subunit deleted mice, were similarly under the developmental influence of a neurosteroid tone. In addition to principal cells, synaptic GABAARs of L2/3 interneurons were modulated by native neurosteroids in a development-dependent manner. In summary, local neurosteroids influence synaptic transmission during a crucial period of cortical neurodevelopment, findings which may be of importance for establishing normal network connectivity

Mentoring promotion/tenure-seeking faculty: principles of good practice within a counselor education program

Approaches to mentoring junior faculty in counselor education departments have received minimal attention in the counseling literature. In this article, the authors describe a successful program based on the 10 principles for good mentoring recommended by Sorcinelli (2000). Application of the principles within a combined formal and informal mentoring approach is described, as are the experiences of junior faculty whose careers have been shaped within this system

Multilevel Interventions Targeting Obesity: Research Recommendations for Vulnerable Populations

The origins of obesity are complex and multifaceted. To be successful, an intervention aiming to prevent or treat obesity may need to address multiple layers of biological, social, and environmental influences

Public perspective on potential treatment intervention harm in clinical trials-terminology and communication

Peer reviewe

State Policies Targeting Junk Food in Schools: Racial/Ethnic Differences in the Effect of Policy Change on Soda Consumption

Objectives. We estimated the association between state policy changes and adolescent soda consumption and body mass index (BMI) percentile, overall and by race/ethnicity