The head or the heart? Measuring the impact of media quality

The number of multimedia applications is constantly increasing. Subjective methods are typically used to determine the level of media quality required in applications, yet recent findings have shown that these have limitations. This paper introduces an objective method for assessing media quality measunng physiological indicators of stress. An experiment examining the impact of video frame rate is presented. With low frame rates, physiological measurements indicated that users were under strain, even though subjectively most reported no differences between low and high frame rates. We conclude that the evaluation of media quality should not be conducted using solely subjective methods

Basic science behind the cardiovascular benefits of exercise

Cardiorespiratory fitness is a strong predictor of cardiovascular (CV) disease and all-cause mortality, with increases in cardiorespiratory fitness associated with corresponding decreases in CV disease risk. The effects of exercise upon the myocardium and vascular system are dependent upon the frequency, intensity and duration of the exercise itself. Following a prolonged period (≥6 months) of regular intensive exercise in previously untrained individuals, resting and submaximal exercising heart rates are typically 5–20 beats lower, with an increase in stroke volume of ∼20% and enhanced myocardial contractility. Structurally, all four heart chambers increase in volume with mild increases in wall thickness, resulting in greater cardiac mass due to increased myocardial cell size. With this in mind, the present paper aims to review the basic science behind the CV benefits of exercise. Attention will be paid to understanding (1) the relationship between exercise and cardiac remodelling; (2) the cardiac cellular and molecular adaptations in response to exercise, including the examination of molecular mechanisms of physiological cardiac growth and applying these mechanisms to identify new therapeutic targets to prevent or reverse pathological remodelling and heart failure; and (3) vascular adaptations in response to exercise. Finally, this review will briefly examine how to optimise the CV benefits of exercise by considering how much and how intense exercise should be

Basic science behind the cardiovascular benefits of exercise

Cardiorespiratory fitness is a strong predictor of cardiovascular (CV) disease and all-cause mortality, with increases in cardiorespiratory fitness associated with corresponding decreases in CV disease risk. The effects of exercise upon the myocardium and vascular system are dependent upon the frequency, intensity and duration of the exercise itself. Following a prolonged period (≥6 months) of regular intensive exercise in previously untrained individuals, resting and submaximal exercising heart rates are typically 5–20 beats lower, with an increase in stroke volume of ∼20% and enhanced myocardial contractility. Structurally, all four heart chambers increase in volume with mild increases in wall thickness, resulting in greater cardiac mass due to increased myocardial cell size. With this in mind, the present paper aims to review the basic science behind the CV benefits of exercise. Attention will be paid to understanding (1) the relationship between exercise and cardiac remodelling; (2) the cardiac cellular and molecular adaptations in response to exercise, including the examination of molecular mechanisms of physiological cardiac growth and applying these mechanisms to identify new therapeutic targets to prevent or reverse pathological remodelling and heart failure; and (3) vascular adaptations in response to exercise. Finally, this review will briefly examine how to optimise the CV benefits of exercise by considering how much and how intense exercise should be

Diversity in the organization of elastin bundles and intramembranous muscles in bat wings

Unlike birds and insects, bats fly with wings composed of thin skin that envelops the bones of the forelimb and spans the area between the limbs, digits, and sometimes the tail. This skin is complex and unusual; it is thinner than typical mammalian skin and contains organized bundles of elastin and embedded skeletal muscles. These elements are likely responsible for controlling the shape of the wing during flight and contributing to the aerodynamic capabilities of bats. We examined the arrangement of two macroscopic architectural elements in bat wings, elastin bundles and wing membrane muscles, to assess the diversity in bat wing skin morphology. We characterized the plagiopatagium and dactylopatagium of 130 species from 17 families of bats using cross‐polarized light imaging. This method revealed structures with distinctive relative birefringence, heterogeneity of birefringence, variation in size, and degree of branching. We used previously published anatomical studies and tissue histology to identify birefringent structures, and we analyzed their architecture across taxa. Elastin bundles, muscles, neurovasculature, and collagenous fibers are present in all species. Elastin bundles are oriented in a predominantly spanwise or proximodistal direction, and there are five characteristic muscle arrays that occur within the plagiopatagium, far more muscle than typically recognized. These results inform recent functional studies of wing membrane architecture, support the functional hypothesis that elastin bundles aid wing folding and unfolding, and further suggest that all bats may use these architectural elements for flight. All species also possess numerous muscles within the wing membrane, but the architecture of muscle arrays within the plagiopatagium varies among families. To facilitate present and future discussion of these muscle arrays, we refine wing membrane muscle nomenclature in a manner that reflects this morphological diversity. The architecture of the constituents of the skin of the wing likely plays a key role in shaping wings during flight

Basic science behind the cardiovascular benefits of exercise

Cardiorespiratory fitness is a strong predictor of cardiovascular (CV) disease and all-cause mortality, with increases in cardiorespiratory fitness associated with corresponding decreases in CV disease risk. The effects of exercise upon the myocardium and vascular system are dependent upon the frequency, intensity and duration of the exercise itself. Following a prolonged period (≥6 months) of regular intensive exercise in previously untrained individuals, resting and submaximal exercising heart rates are typically 5–20 beats lower, with an increase in stroke volume of ∼20% and enhanced myocardial contractility. Structurally, all four heart chambers increase in volume with mild increases in wall thickness, resulting in greater cardiac mass due to increased myocardial cell size. With this in mind, the present paper aims to review the basic science behind the CV benefits of exercise. Attention will be paid to understanding (1) the relationship between exercise and cardiac remodelling; (2) the cardiac cellular and molecular adaptations in response to exercise, including the examination of molecular mechanisms of physiological cardiac growth and applying these mechanisms to identify new therapeutic targets to prevent or reverse pathological remodelling and heart failure; and (3) vascular adaptations in response to exercise. Finally, this review will briefly examine how to optimise the CV benefits of exercise by considering how much and how intense exercise should be

Basic science behind the cardiovascular benefits of exercise

Cardiorespiratory fitness is a strong predictor of cardiovascular (CV) disease and all-cause mortality, with increases in cardiorespiratory fitness associated with corresponding decreases in CV disease risk. The effects of exercise upon the myocardium and vascular system are dependent upon the frequency, intensity and duration of the exercise itself. Following a prolonged period (≥6 months) of regular intensive exercise in previously untrained individuals, resting and submaximal exercising heart rates are typically 5–20 beats lower, with an increase in stroke volume of ∼20% and enhanced myocardial contractility. Structurally, all four heart chambers increase in volume with mild increases in wall thickness, resulting in greater cardiac mass due to increased myocardial cell size. With this in mind, the present paper aims to review the basic science behind the CV benefits of exercise. Attention will be paid to understanding (1) the relationship between exercise and cardiac remodelling; (2) the cardiac cellular and molecular adaptations in response to exercise, including the examination of molecular mechanisms of physiological cardiac growth and applying these mechanisms to identify new therapeutic targets to prevent or reverse pathological remodelling and heart failure; and (3) vascular adaptations in response to exercise. Finally, this review will briefly examine how to optimise the CV benefits of exercise by considering how much and how intense exercise should be

The relationship between media quality and user cost in networked multimedia applications

The research reported in this thesis assesses the impact of media quality degradations in Internet multimedia conferencing on users. Low quality audio and video can be experienced, therefore it is important to determine the minimum levels of quality needed to perform specific tasks. This has most commonly been investigated using subjective measures, however the research reported in this thesis adopted a 3-factor evaluation framework of task performance, user satisfaction and user cost. User satisfaction was measured subjectively, whereas physiological indicators of perceptual strain were utilised to measure user cost. Physiological measures provide continuous data throughout a session, are not subject to cognitive mediation and taking such measurements does not interfere with the user's task. Five experiments were performed investigating audio and video quality degradations. With the exception of one passive listening task, all tasks used were based on remote interviews, as they fully exploit the capabilities of the application. Results showed that physiological responses to media quality degradations can be detected in passive, perceptual tasks. However, active participation in a task made it more difficult to detect changes due to quality degradations. In all experiments physiological measures gave information on the nature of the tasks being performed and effects of variables such as order. The results of this research were then used in three further experiments in the areas of VR and web quality of service and design. In conclusion, the physiological measures utilised in the research reported in this thesis can be employed to assess the impact of media quality degradations in passive perceptual tasks and to give general information about the nature of the task being performed

A coherent middle Pliocene magnetostratigraphy, Wanganui Basin, New Zealand

We document magnetostratigraphies for three river sections (Turakina, Rangitikei, Wanganui) in Wanganui Basin and interpret them as corresponding to the Upper Gilbert, the Gauss and lower Matuyama Chrons of the Geomagnetic Polarity Timescale, in agreement with foraminiferal biostratigraphic datums. The Gauss-Gilbert transition (3.58 Ma) is located in both the Turakina and Wanganui River sections, while the Gauss-Matuyama transition (2.58 Ma) is located in all three sections, as are the lower and upper boundaries of the Mammoth (3.33–3.22 Ma) and Kaena (3.11–3.04 Ma) Subchrons. Our interpretations are based in part on the re-analysis of existing datasets and in part on the acquisition and analysis of new data, particularly for the Wanganui River section. The palaeomagnetic dates of these six horizons provide the only numerical age control for a thick (up to 2000 m) mudstone succession (Tangahoe Mudstone) that accumulated chiefly in upper bathyal and outer neritic palaeoenvironments. In the Wanganui River section the mean sediment accumulation rate is estimated to have been about 1.8 m/k.y., in the Turakina section it was about 1.5 m/k.y., and in the Rangitikei section, the mean rate from the beginning of the Mammoth Subchron to the Hautawa Shellbed was about 1.1 m/k.y. The high rates may be associated with the progradation of slope clinoforms northward through the basin. This new palaeomagnetic timescale allows revised correlations to be made between cyclothems in the Rangitikei River section and the global Oxygen Isotope Stages (OIS) as represented in Ocean Drilling Program (ODP) Site 846. The 16 depositional sequences between the end of the Mammoth Subchron and the Gauss-Matuyama Boundary are correlated with OIS MG2 to 100. The cyclothems average 39 k.y. in duration in our age model, which is close to the 41 k.y. duration of the orbital obliquity cycles. We support the arguments advanced recently in defence of the need for local New Zealand stages as a means of classifying New Zealand sedimentary successions, and strongly oppose the proposal to move stage boundaries to selected geomagnetic polarity transitions. The primary magnetisation of New Zealand mudstone is frequently overprinted with secondary components of diagenetic origin, and hence it is often difficult to obtain reliable magnetostratigraphic records. We suggest specific approaches, analytical methods, and criteria to help ensure robustness and coherency in the palaeomagnetic identification of chron boundaries in typical New Zealand Cenozoic mudstone successions

Arachnid toxinology in Australia: From clinical toxicology to potential applications

The unique geographic isolation of Australia has resulted in the evolution of a distinctive range of Australian arachnid fauna. Through the pioneering work of a number of Australian arachnologists, toxinologists, and clinicians, the taxonomy and distribution of new species, the effective clinical treatment of envenomation, and the isolation and characterisation of the many distinctive neurotoxins, has been achieved. In particular, work has focussed on several Australian arachnids, including red-back and funnel-web spiders, paralysis ticks, and buthid scorpions that contain neurotoxins capable of causing death or serious systemic envenomation. In the case of spiders, species-specific antivenoms have been developed to treat envenomed patients that show considerable cross-reactivity. Both in vitro and clinical case studies have shown they are particularly efficacious in the treatment of envenomation by spiders even from unrelated families. Despite their notorious reputation, the high selectivity and potency of a unique range of toxins from the venom of Australian arachnids will make them invaluable molecular tools for studies of neurotransmitter release and vesicle exocytosis as well as ion channel structure and function. The venoms of funnel-web spiders, and more recently Australian scorpions, have also provided a previously untapped rich source of insect-selective neurotoxins for the future development of biopesticides and the characterisation of previously unvalidated insecticide targets. This review provides a historical viewpoint of the work of many toxinologists to isolate and characterise just some of the toxins produced by such a unique group of arachnids and examines the potential applications of these novel peptides. © 2006 Elsevier Ltd. All rights reserved

Review of medal predictions for South Africa in the Delhi 2010 Commonwealth Games

Objectives. This paper reviews South Africa’s performance in the Delhi 2010 Commonwealth Games relative to predicted medal success. Methods. Forecasts based on the nation’s previous success are compared against medals won in Delhi. Results. Actual performance is in line with predicted performance in terms of gold medals but total medals won are below expectations. Conclusion. The findings are of potential value to relevant sports authorities and follow up research is proposed