HIV-1 Transgenic Rat: Selective Alterations In Motivation And Histological Examination Of Medium Spiny Neurons Of The Nucleus Accumbens

Motivational alterations in HIV-1+ individuals are associated with decreased performance on tasks involving frontal-subcortical circuitry and the nucleus accumbens. In the present study, the HIV-1 transgenic (Tg) rat was used to assess long-term HIV-1 viral protein exposure on motivated behavior using activity chambers (40x40cm) and voluntary wheel running. Adult ovariectomized female HIV-1 Tg animals (n=21) to F344 controls (n=26) were pair-housed under a 12:12 light/dark cycle. Voluntary running was measured with 34 cm-diameter running wheels for ~60 minutes/day for 3 ½ months. There were no significant differences between HIV-1 Tg and F344 control rats in voluntary wheel running during the light phase. Animals were subsequently run in the nocturnal phase of their light/dark cycle. The F344 controls continued to escalate their overall running distances and surpassed the stabilized HIV-1 Tg group after ~4 weeks of nocturnal running, until reaching their asymptotic plateau at week 11. Neither maximal running speed, nor the latency to initiate running or running bout length were significantly different between groups. However, the groups were different in the number of running bouts per session, as a function of the HIV-1 transgene. Collectively, the selective alterations in the motivation for voluntary wheel running and activity chamber locomotor activity, suggests a disruption of the motivational circuitry within the HIV-1 Tg rat brain. Examination of Medium Spiny Neurons of the nucleus accumbens showed significant alterations in dendritic spine length and spine head diameter. Further study of these alterations in spine parameters may help elucidate the mechanisms of motivational alterations in HIV-1+individuals

The religious dimension of lay leadership in Catholic schools: Preserving Catholic culture in an era of change

This article is a qualitative study of the practice of leadership in Catholic schools in Australia. Within an interpretivist framework, a multiple case study of six lay principals was employed. Findings suggest that successful leadership in Catholic schools is highly influenced by the cultural and spiritual capital that a principal brings to a school, signifying a fundamental importance of appointing principals who are not only professionally competent, but who are spiritually competent as well. The relationship between the lay Catholic principal in the parish and the parish priest emerged as a challenging issue in many contexts. Indeed, it was highly problematic for some principals

Hexakis Icosahedron Frame-skin Vacuum Lighter Than Air Vehicle

A vacuum lighter than air vehicle (VLTAV) includes a rigid frame of rods connected together to form a hexakis icosahedron. A membrane skin covers the rigid frame and defines therewith a vessel configured to hold an internal vacuum that allows the vessel to float in the air. The plurality of rods and membrane skin have weights and dimensions that result in a neutral and/or positive buoyancy for the vessel while preventing geometric instability

Evaluation of the Thorax of Manduca Sexta for Flapping Wing Micro Air Vehicle Applications

n the 1990\u27s, DARPA awarded several contracts to companies to research, design, and construct a Flapping Wing Micro Air Vehicle (FWMAV). The tobacco hornworm hawkmoth (Manduca sexta) provides an excellent model from which to gather knowledge pertaining to the development of a Flapping Wing Micro Air Vehicle (FWMAV). One of the major challenges in design of a FWMAV is the energy demanding nature of low Reynolds number flapping flight. Therefore, an understanding of the power required by the flight muscles to actuate the wings is essential for the design of a FWMAV. The M.sexta wing/thorax mechanism was evaluated as a mechanical system in order to gain insight to the mechanical power required to produce the full natural wing stroke. A unique dynamic load device was designed and constructed to mechanically actuate the upstroke and downstroke of the M.sexta in order to achieve the full flapping motion. Additionally, the forces applied through the flight muscles were directly measured in order to attain the power requirements of the flight muscles simultaneously. The experiment yielded wing stroke values of + 60 and – 35 degrees, which is what is seen in nature during hovering. The DVM and DLM muscle groups were calculated to have a power density of 112 W/kg with the vehicle energy density being 2.5 W/kg. The power output requirement indicates the need for a lightweight and energy-dense power source/actuator combination for the development of FWMAVs

Making it work: identifying the challenges of collaborative international research

In this article, we explore the challenges – and benefits – of conducting collaborative research on an international scale. The authors – from Australia, Canada, and New Zealand – draw upon their experiences in designing and conducting a three-country study. The growing pressures on scholars to work in collaborative research teams are described, and key findings and reflections are presented. It is claimed that such work is a highly complex and demanding extension to the academic’s role. The authors conclude that, despite the somewhat negative sense that this reflection may convey, the synergies gained and the valuable comparative learning that took place make overcoming these challenges a worthwhile process. The experiences as outlined in this paper suggest that developing understandings of the challenges inherent in undertaking international collaborative research might well be a required component of the professional development opportunities afforded to new scholars

Exercise as a therapeutic for HIV-1-associated neurocognitive deficits

Human Immunodeficiency Virus (HIV-1) afflicts nearly 38 million individuals worldwide (Joseph et al., 2013; “WHO | HIV/AIDS,” 2016). Despite the reduction in disease mortality due to increased use of antiretroviral medication, HIV-1 associated neurocognitive disorder (HAND) affects approximately 50% of HIV infected individuals (Antinori et al., 2007; Castellon, Hinkin, Wood, & Yarema, 1998; Castelo, Sherman, Courtney, Melrose, & Stern, 2006; Cysique & Brew, 2009; Heaton et al., 2011, 2015). The brain itself is particularly sensitive to HIV-1 related viral proteins and viral infection (Masliah, DeTeresa, Mallory, & Hansen, 2000), thus, it is vital to empirically examine potentially effective therapeutics which may be capable of improving cognition in HIV-1 patients. In the contemporary literature, cognitive deficiencies encompassed by HAND include deficits in: attention/information processing, language, abstraction-executive function, complex perceptual motor skills, memory (short-term and working memory), learning and recall, simple motor skills and sensory perceptual abilities, as defined by the most recent HIV-1 nosology (Antinori et al., 2007). Therapeutics capable of improving neurocognitive dysfunction in the HIV-1 brain has yet to be established; therefore, the current study examined a potential therapeutic theoretically capable of improving HAND related cognitive dysfunction: physical activity. Physical activity has been shown to be the strongest environmental factor capable of promoting the genesis of new neurons in the subgranular zone of the hippocampal dentate gyrus (Fuss et al., 2014; Ji et al., 2014; Klein et al., 2016; M.-H. Lee et al., 2013; Naylor et al., 2008; van Praag, Christie, Sejnowski, & Gage, 1999; van Praag, Kempermann, & Gage, 1999; van Praag et al., 2002; van Praag, Shubert, Zhao, & Gage, 2005; Vivar & van Praag, 2013). Furthermore, when examining the relationship between physical activity and HIV-1 associated cognitive decline, there appears to be an association between acute physical activity and cognitive function in human HIV-1+ patients (Dufour et al., 2013, 2018), evidence which suggests physical activity may be capable of preserving/promoting cognitive function in the HIV-1 brain. The current study determined whether promoting neurogenesis through physical activity can act as a neuroprotective/neurorestorative therapeutic agent capable of attenuating the progression of HIV-1 cognitive pathology. Upon completion of the current study, the role of chronic HIV-1 viral protein expression on dentate gyrus neurogenesis in the HIV-1 transgenic (Tg) rat brain was empirically established. The current results provide evidence that HIV-1 viral proteins do inhibit neurogenesis (as determined by doublecortin immunolableling), and that wheel running did not significantly increase neurogenesis. However, wheel running significantly increased dendritic spine length, volume and head diameter, as well as dendritic length. These results suggest that physical activity may be an effective therapeutic for improving HIV-1-dependent neurological synaptodendritic damage due to the expression of HIV-1 viral proteins

Uniform shrinking and expansion under isotropic Brownian flows

We study some finite time transport properties of isotropic Brownian flows. Under a certain nondegeneracy condition on the potential spectral measure, we prove that uniform shrinking or expansion of balls under the flow over some bounded time interval can happen with positive probability. We also provide a control theorem for isotropic Brownian flows with drift. Finally, we apply the above results to show that under the nondegeneracy condition the length of a rectifiable curve evolving in an isotropic Brownian flow with strictly negative top Lyapunov exponent converges to zero as $t\to \infty$ with positive probability

Micro-political leadership strategies used by curriculum leaders in one Queensland school in implementing the national curriculum

Despite several countries having introduced a national curriculum, the literatureon how school leaders implement such curriculum is surprisingly scant. This article reportson one aspect of a larger study that investigated how members of a school curriculumleadership team implemented Australia’s first national curriculum. The aspect reported in thisarticle is concerned with leadership strategies used by these members in the implementationof this curriculum. The findings draw on semi-structured in-depth interviews of 29participants, comprising 17 members of this team and 11 teachers in the case school, and oneschool sector curriculum officer. Blase and Anderson’s (1995) micro-political leadershipmatrix was used to analyse the research findings, which shed light on the micro-politicalleadership practices regarding how school leaders implement large-scale mandatedcurriculum change. This analysis highlighted the need for those with curriculum leadership tounderstand micro-politics in leading such change.© 2018 Australian Council for Educational Leader

Vibronic coupling explains the ultrafast carotenoid-to-bacteriochlorophyll energy transfer in natural and artificial light harvesters

The initial energy transfer in photosynthesis occurs between the light-harvesting pigments and on ultrafast timescales. We analyze the carotenoid to bacteriochlorophyll energy transfer in LH2 Marichromatium purpuratum as well as in an artificial light-harvesting dyad system by using transient grating and two-dimensional electronic spectroscopy with 10 fs time resolution. We find that F\"orster-type models reproduce the experimentally observed 60 fs transfer times, but overestimate coupling constants, which leads to a disagreement with both linear absorption and electronic 2D-spectra. We show that a vibronic model, which treats carotenoid vibrations on both electronic ground and excited state as part of the system's Hamiltonian, reproduces all measured quantities. Importantly, the vibronic model presented here can explain the fast energy transfer rates with only moderate coupling constants, which are in agreement with structure based calculations. Counterintuitively, the vibrational levels on the carotenoid electronic ground state play a central role in the excited state population transfer to bacteriochlorophyll as the resonance between the donor-acceptor energy gap and vibrational ground state energies is the physical basis of the ultrafast energy transfer rates in these systems