Interindividual Differences in Leg Muscle Mass and Pyruvate Kinase Activity Correlate with Interindividual Differences in Jumping Performance of Hyla multilineata

Frog jumping is an excellent model system for examining the structural basis of interindividual variation in burst locomotor performance. Some possible factors that affect jump performance, such as total body size, hindlimb length, muscle mass, and muscle mechanical and biochemical properties, were analysed at the interindividual (intraspecies) level in the tree frog Hyla multilineata. The aim of this study was to determine which of these physiological and anatomical variables both vary between individuals and are correlated with interindividual variation in jump performance. The model produced via stepwise linear regression analysis of absolute data suggested that 62% of the interindividual variation in maximum jump distance could be explained by a combination of interindividual variation in absolute plantaris muscle mass, total hindlimb muscle mass ( excluding plantaris muscle), and pyruvate kinase activity. When body length effects were removed, multiple regression indicated that the same independent variables explained 43% of the residual interindividual variation in jump distance. This suggests that individuals with relatively large jumping muscles and high pyruvate kinase activity for their body size achieved comparatively large maximal jump distances for their body size.

Government relations, government regulations: jumping through the hoops

Over the last decade, telehealth in Australia has been primarily facilitated and driven by government funding. The government now has a major policy initiative in online health. However, in pursuing the broad initiative there is a danger that some of the smaller components can get lost, and this is probably what has happened to telehealth. There appear to be a number of steps required if telehealth in Australia is to keep up the pace of development that occurred in the 1990s, as we move into what is now being called the era of e-health, involving broadband Internet health service delivery. This area is changing extremely rapidly and is increasingly migrating away from the public sector in Australia, where most of the developmental work has occurred, and into the private sector. Many of the issues that require consideration within the domain of e-health in Australia are also relevant to other countries. E-health will significantly change the way that health-care is practised in future, and it is clear that it is the human factors that are more difficult to overcome, rather than the technological ones.

Government relations, government regulations: Jumping through the hoops

Over the last decade, telehealth in Australia has been primarily facilitated and driven by government funding. The government now has a major policy initiative in online health. However, in pursuing the broad initiative there is a danger that some of the smaller components can get lost, and this is probably what has happened to telehealth. There appear to be a number of steps required if telehealth in Australia is to keep up the pace of development that occurred in the 1990s, as we move into what is now being called the era of e-health, involving broadband Internet health service delivery. This area is changing extremely rapidly and is increasingly migrating away from the public sector in Australia, where most of the developmental work has occurred, and into the private sector. Many of the issues that require consideration within the domain of e-health in Australia are also relevant to other countries. E-health will significantly change the way that health-care is practised in future, and it is clear that it is the human factors that are more difficult to overcome, rather than the technological ones.

Locomotor performance of closely related Tropidurus species: relationships with physiological parameters and ecological divergence

Tropidurid lizards have colonized a variety of Brazilian open environments without remarkable morphological variation, despite ecological and structural differences among habitats used. This study focuses on two Tropidurus sister-species that, despite systematic proximity and similar morphology, exhibit great ecological divergence and a third ecologically generalist congeneric species providing an outgroup comparison. We quantified jumping capacity and sprint speed of each species on sand and rock to test whether ecological divergence was also accompanied by differences in locomotor performance. Relevant physiological traits possibly associated with locomotor performance metabolic scopes and fiber type composition, power output and activity of the enzymes citrate synthase, pyruvate kinase and lactate dehydrogenase of the iliofibularis muscle - were also compared among the three Tropidurus species. We found that the two sister-species exhibited remarkable differences in jumping performance, while Tropidurus oreadicus, the more distantly related species, exhibited intermediate values. Tropidurus psamonastes, a species endemic to sand dunes, exhibited high absolute sprint speeds on sand, jumped rarely and possessed a high proportion of glycolytic fibers and low activity of citrate synthase. The sister-species Tropidurus itambere, endemic to rocky outcrops, performed a large number of jumps and achieved lower absolute sprint speed than T. psamonastes. This study provides evidence of rapid divergence of locomotor parameters between sister-species that use different substrates, which is only partially explained by variation in physiological parameters of the iliofibularis muscle.

Time motion analysis of 2001 and 2002 super 12 rugby

The aim of this study was to quantify movements of Super 12 rugby players in competition because information on elite rugby players' movements is unavailable. Players were categorized into forwards [front (n = 16) and back row (n = 15)] and backs [inside (n = 9) and outside backs (n = 7)] and their movements analysed by video-based time motion analysis. Movements were classified as rest (standing, walking and jogging) and work (striding, sprinting, static exertion, jumping, lifting or tackling). The total time, number and duration of individual activities were assessed, with differences between groups evaluated using independent sample t-tests (unequal variances), while differences between halves were assessed with paired sample t-tests. Forwards had 7:47 min:s (95% confidence limits: 6:39 to 8:55 min:s, P

Was an increase in cocaine use among injecting drug users in New South Wales, Australia, accompanied by an increase in violent crime?

Background: A sharp reduction in heroin supply in Australia in 2001 was followed by a large but transient increase in cocaine use among injecting drug users (IDU) in Sydney. This paper assesses whether the increase in cocaine use among IDU was accompanied by increased rates of violent crime as occurred in the United States in the 1980s. Specifically, the paper aims to examine the impact of increased cocaine use among Sydney IDU upon police incidents of robbery with a weapon, assault and homicide. Methods: Data on cocaine use among IDU was obtained from the Illicit Drug Reporting System (IDRS). Monthly NSW Police incident data on arrests for cocaine possession/ use, robbery offences, homicides, and assaults, were obtained from the Bureau of Crime Statistics and Research. Time series analysis was conducted on the police data series where possible. Semi-structured interviews were conducted with representatives from law enforcement and health agencies about the impacts of cocaine use on crime and policing. Results: There was a significant increase in cocaine use and cocaine possession offences in the months immediately following the reduction in heroin supply. There was also a significant increase in incidents of robbery where weapons were involved. There were no increases in offences involving firearms, homicides or reported assaults. Conclusion: The increased use of cocaine among injecting drug users following the heroin shortage led to increases in violent crime. Other States and territories that also experienced a heroin shortage but did not show any increases in cocaine use did not report any increase in violent crimes. The violent crimes committed did not involve guns, most likely because of its stringent gun laws, in contrast to the experience of American cities that have experienced high rates of cocaine use and violent crime.

The state of history and the empire of metaphysics [Review]

One of the curious things about this challenging book is that its ostensible subject— the Saxon medical and political scientist Hermann Conring (1606–1681)— is not mentioned in the title. Constantin Fasolt argues that we cannot know what Conring really thought or meant in his writings, which means that his topic cannot be Conring as such and must instead be that which occludes our knowledge of him, the titular limits of history. Given that we do in fact learn a good deal about Conring from Fasolt’s book, we can only hope that the decapitation of its subject will be rectified in a subsequent edition, or perhaps by the restorative work of librarians putting together subject headings. And yet Fasolt’s decision is understandable, for Conring is indeed a stalking-horse for a much bigger quarry: historiography and the historical consciousness. By “history” Fasolt understands a way of imposing intelligibility on the world, which is founded on the twin assumptions that the past is gone and unchangeable, and that the meaning of texts can be determined by placing them in their historical contexts (ix). In challenging this mode of intelligibility, Fasolt is not attempting to improve professiona history—it’s already as good as it can be—but to displace it. He regards his work as a declaration of “independence from historical consciousness” (32). At the same time, Fasolt insists that he is not simply jumping from historiography to philosophy, or attempting to preempt history with ontology (37-39). That has been tried by Nietzsche and Heidegger, who have been tainted by Nazism (Fasolt thinks unfairly). It has also been attempted by modern philosophers from Gadamer to Foucault and Charles Taylor who, in failing to address the “violence” that its mode of intelligibility does to the world, have not succeeded in outflanking history. Perhaps, Fasolt wonders, it is only the personal experience of those who have been subject to this violence—the experience of those who have been subject to historical examination—that can break the spell of history. Fasolt’s disclaimer notwithstanding, in the course of these remarks I shall argue that he is indeed jumping from history to philosophy, or attempting to outflank history by subjecting it to a particular metaphysical understanding. I shall do so in part by sketching the recent intellectual history of this move—a historical examination that I hope inflicts as little violence as possible on Fasolt’s argument.

Short- and long-term consequences of thermal variation in the larval environment of anurans

To survive adverse or unpredictable conditions in the ontogenetic environment, many organisms retain a level of phenotypic plasticity that allows them to meet the challenges of rapidly changing conditions. Larval anurans are widely known for their ability to modify behaviour, morphology and physiological processes during development, making them an ideal model system for studies of environmental effects on phenotypic traits. Although temperature is one of the most important factors influencing the growth, development and metamorphic condition of larval anurans, many studies have failed to include ecologically relevant thermal fluctuations among their treatments. We compared the growth and age at metamorphosis of striped marsh frogs Limnodynastes peronii raised in a diurnally fluctuating thermal regime and a stable regime of the same mean temperature. We then assessed the long-term effects of the larval environment on the morphology and performance of post-metamorphic frogs. Larval L. peronii from the fluctuating treatment were significantly longer throughout development and metamorphosed about 5 days earlier. Frogs from the fluctuating group metamorphosed at a smaller mass and in poorer condition compared with the stable group, and had proportionally shorter legs. Frogs from the fluctuating group showed greater jumping performance at metamorphosis and less degradation in performance during a 10-week dormancy. Treatment differences in performance could not be explained by whole-animal morphological variation, suggesting improved contractile properties of the muscles in the fluctuating group.

What does the animal model teach us about the effects of physical activity on growing bone?

Experiments to design physical activity programs that optimize their osteogenic potential are difficult to accomplish in humans. The aim of this article is to review the contributions that animal studies have made to knowledge of the loading conditions that are osteogenic to the skeleton during growth, as well as to consider to what extent animal studies fail to provide valid models of physical activity and skeletal maturation. Controlled loading studies demonstrate that static loads are ineffective, and that bone formation is threshold driven and dependent on strain rate, amplitude, and duration of loading. Only a few loading cycles per session are required, and distributed bouts are more osteogenic than sessions of long duration. Finally, animal models fail to inform us of the most appropriate ways to account for the variations in biological maturation that occur in our studies of children and adolescents, requiring the use of techniques for studying human growth and development.

Multiphoton high-resolution 3D imaging of Langerhans cells and keratinocytes in the mouse skin model adopted for epidermal powdered immunization

Langerhans cells (LCs) can be targeted with DNA-coated gold micro-projectiles ("Gene Gun") to induce potent cellular and humoral immune responses. It is likely that the relative volumetric distribution of LCs and keratinocytes within the epidermis impacts on the efficacy of Gene Gun immunization protocols. This study quantified the three-dimensional (3D) distribution of LCs and keratinocytes in the mouse skin model with a near-infrared multiphoton laser-scanning microscope (NIR-MPLSM). Stratum corneum (SC) and viable epidermal thickness measured with MPLSM was found in close agreement with conventional histology. LCs were located in the vertical plane at a mean depth of 14.9 mum, less than 3 mum above the dermo-epidermal boundary and with a normal histogram distribution. This likely corresponds to the fact that LCs reside in the suprabasal layer (stratum germinativum). The nuclear volume of keratinocytes was found to be approximately 1.4 times larger than that of resident LCs (88.6 mum3). Importantly, the ratio of LCs to keratinocytes in mouse ear skin (1:15) is more than three times higher than that reported for human breast skin (1:53). Accordingly, cross-presentation may be more significant in clinical Gene Gun applications than in pre-clinical mouse studies. These interspecies differences should be considered in pre-clinical trials using mouse models.

Numerical analysis of gas and micro-particle interactions in a hand-held shock-tube device

A unique hand-held gene gun is employed for ballistically delivering biomolecules to key cells in the skin and mucosa in the treatment of the major diseases. One of these types of devices, called the Contoured Shock Tube (CST), delivers powdered micro-particles to the skin with a narrow and highly controllable velocity distribution and a nominally uniform spatial distribution. In this paper, we apply a numerical approach to gain new insights in to the behavior of the CST prototype device. The drag correlations proposed by Henderson (1976), Igra and Takayama (1993) and Kurian and Das (1997) were applied to predict the micro-particle transport in a numerically simulated gas flow. Simulated pressure histories agree well with the corresponding static and Pitot pressure measurements, validating the CFD approach. The calculated velocity distributions show a good agreement, with the best prediction from Igra & Takayama correlation (maximum discrepancy of 5%). Key features of the gas dynamics and gas-particle interaction are discussed. Statistic analyses show a tight free-jet particle velocity distribution is achieved (570 +/- 14.7 m/s) for polystyrene particles (39 +/- 1 mu m), representative of a drug payload.