914 research outputs found
Marketing implications of traditional and ICT-mediated leisure activities
This study investigates the role of traditional and information and communication technology (ICT)-mediated leisure activities in consumer behaviour. An online survey of 558 members and 1319 ex-members of an Australian DVD rental company gathered preferences for nine traditional leisure activities and seven ICT-mediated leisure activities. The results of a cluster analysis showed four clusters with significant cluster differences across leisure activities and across demographics and consumer behaviours. For practitioners, the study illustrates how profiling customers on their leisure preferences can increase advertising effectiveness, reflect loyalty and help predict customer lifetime value. For academia, the results reveal how another consumer dimension, leisure activities, relates to demographic and behavioural characteristics
A dynamic simulation model for possum and gorse control on a farm woodlot
Managers of farm woodlots in New Zealand are confronted by two major problems: possums and gorse. If these remain uncontrolled then they have a severe impact on the returns from farm woodlots. This paper presents a system dynamics model which has been developed to assist in the analysis of control measures for managing gorse and possums on a farm woodlot in the Makara Valley, Wellington. The model has four main sectors: a tree growth module for radiata pine; a growth module for gorse; a module for the stock of possums present in the habitat; and a module of financial indicators. A number of control experiments are presented which indicate the long term financial and physical consequences of different gorse and possum control measures. The model clearly demonstrates the complex nature of the dynamic behaviour of a system involving biological and environmental factors (ie possums, gorse and trees) and human intervention (in terms of silviculture, and possum and gorse control)
Superoscillations and tunneling times
It is proposed that superoscillations play an important role in the
interferences which give rise to superluminal effects. To exemplify that, we
consider a toy model which allows for a wave packet to travel, in zero time and
negligible distortion a distance arbitrarily larger than the width of the wave
packet. The peak is shown to result from a superoscillatory superposition at
the tail. Similar reasoning applies to the dwell time.Comment: 12 page
Are shoulder counter rotation and hip shoulder separation angle representative metrics of three-dimensional spinal kinematics in cricket fast bowling?
This study aimed to investigate the relationship between shoulder counter-rotation (SCR), hip shoulder separation (HSS) and three-dimensional spinal kinematics during fast bowling in cricket. Thirty five elite male fast bowlers were analysed using three-dimensional inertial sensors on the spine. Lumbar, thoracic and thoracolumbar kinematics were determined during the delivery stride. Spearman's pairwise correlations displayed significant associations between SCR, thoracic and thoracolumbar lateral flexion between the back foot impact and max contralateral rotation phase of the delivery stride (rs = -.462 and -.460). HSS and thoracolumbar lateral flexion displayed a significant correlation between back foot impact and max contralateral rotation (rs = -.552). No other significant correlations were observed. These results suggest SCR and HSS are modestly related to lateral flexion, leaving a large component of SCR and HSS unrelated to specific three-dimensional spinal kinematics. It is possible that this represents changes in whole spinal orientation and not resultant spinal motion. Despite this, SCR remains the only metric currently related to injury and therefore is important; however it is only a very modest proxy for more traditional descriptions of spinal motion
Cooperative Ring Exchange and Quantum Melting of Vortex Lattices in Atomic Bose-Einstein Condensates
Cooperative ring-exchange is suggested as a mechanism of quantum melting of
vortex lattices in a rapidly-rotating quasi two dimensional atomic
Bose-Einstein condensate (BEC). Using an approach pioneered by Kivelson et al.
[Phys. Rev. Lett. {\bf 56}, 873 (1986)] for the fractional quantized Hall
effect, we calculate the condition for quantum melting instability by
considering large-correlated ring exchanges in a two-dimensional Wigner crystal
of vortices in a strong `pseudomagnetic field' generated by the background
superfluid Bose particles. BEC may be profitably used to address issues of
quantum melting of a pristine Wigner solid devoid of complications of real
solids.Comment: 7 pages, 1 figure, to appear in Physical Review
Grain boundary effects on magnetotransport in bi-epitaxial films of LaSrMnO
The low field magnetotransport of LaSrMnO (LSMO) films
grown on SrTiO substrates has been investigated. A high qualtity LSMO film
exhibits anisotropic magnetoresistance (AMR) and a peak in the
magnetoresistance close to the Curie temperature of LSMO. Bi-epitaxial films
prepared using a seed layer of MgO and a buffer layer of CeO display a
resistance dominated by grain boundaries. One film was prepared with seed and
buffer layers intact, while a second sample was prepared as a 2D square array
of grain boundaries. These films exhibit i) a low temperature tail in the low
field magnetoresistance; ii) a magnetoconductance with a constant high field
slope; and iii) a comparably large AMR effect. A model based on a two-step
tunneling process, including spin-flip tunneling, is discussed and shown to be
consistent with the experimental findings of the bi-epitaxial films.Comment: REVTeX style; 14 pages, 9 figures. Figure 1 included in jpeg format
(zdf1.jpg); the eps was huge. Accepted to Phys. Rev.
Hypogene Calcitization: Evaporite Diagenesis in the Western Delaware Basin
Evaporite calcitization within the Castile Formation of the Delaware Basin is more widespread and diverse than originally recognized. Coupled field and GIS studies have identified more than 1000 individual occurrences of calcitization within the Castile Formation outcrop area, which includes both calcitized masses (limestone buttes) and laterally extensive calcitized horizons (limestone sheets). Both limestone buttes and sheets commonly contain a central brecciated zone that we attribute to hypogene dissolution. Lithologic fabric of calcitized zones ranges from little alteration of original varved laminae to fabrics showing extensive laminae distortion as well as extensive vuggy and open cavernous porosity. Calcitization is most abundant in the western portion of the Castile outcrop region where surface denudation has been greatest. Calcitization often forms linear trends, indicating fluid migration along fractures, but also occurs as dense clusters indicating focused, ascending, hydrocarbon-rich fluids. Native sulfur, secondary tabular gypsum (i.e. selenite) and hypogene caves are commonly associated with clusters of calcitization. This assemblage suggests that calcium sulfate diagenesis within the Castile Formation is dominated by hypogene speleogemesis
Dual stem cell therapy synergistically improves cardiac function and vascular regeneration following myocardial infarction
Since both myocardium and vasculature in the heart are excessively damaged following myocardial infarction (MI), therapeutic strategies for treating MI hearts should concurrently target both so as to achieve true cardiac repair. Here we demonstrate a concomitant method that exploits the advantages of cardiomyocytes derived from human induced pluripotent stem cells (hiPSC-CMs) and human mesenchymal stem cell-loaded patch (hMSC-PA) to amplify cardiac repair in a rat MI model. Epicardially implanted hMSC-PA provide a complimentary microenvironment which enhances vascular regeneration through prolonged secretion of paracrine factors, but more importantly it significantly improves the retention and engraftment of intramyocardially injected hiPSC-CMs which ultimately restore the cardiac function. Notably, the majority of injected hiPSC-CMs display adult CMs like morphology suggesting that the secretomic milieu of hMSC-PA constitutes pleiotropic effects in vivo. We provide compelling evidence that this dual approach can be a promising means to enhance cardiac repair on MI hearts.11Ysciescopu
IMMUNOPATHOLOGICAL STUDIES OF ORTHOTOPIC HUMAN LIVER ALLOGRAFTS
Twenty-six specimens obtained from twenty human orthotopic liver allografts 10-968 days after transplantation were studied by light microscopy, electron microscopy, and immunofluorescence. The main lesions consisted of mononuclear-cell infiltration around the portal tracts, centrilobular cholestasis, liver-cell atrophy and reticulin collapse, obliterative intimal thickening of hepatic arteries, and fibrosis. Moderate amounts of IgG and/or IgM and complement (β1C/β1A globulin or C'lq) were observed in four of the liver samples and smaller deposits were present in another five. A further three specimens contained IgG without complement. IgA was detected in only one of the samples. The immunoglobulins were found in the walls of the portal and central veins and of the sinusoids in all thirteen positive liver samples, in the walls of branches of the hepatic artery in three, and in the cytoplasm of some of the mononuclear cells infiltrating the portal tracts in nine of the specimens. Fibrinogen was seen in eight of the samples, usually in the spaces of Disse. Accumulations of immunoglobulins and complement were less frequent in liver than in kidney and heart allografts. These findings suggest that in the failure of human liver allografts cell-mediated immunity and non-immunological factors may be more important than humoral antibody. © 1972
Thermostatistics of deformed bosons and fermions
Based on the q-deformed oscillator algebra, we study the behavior of the mean
occupation number and its analogies with intermediate statistics and we obtain
an expression in terms of an infinite continued fraction, thus clarifying
successive approximations. In this framework, we study the thermostatistics of
q-deformed bosons and fermions and show that thermodynamics can be built on the
formalism of q-calculus. The entire structure of thermodynamics is preserved if
ordinary derivatives are replaced by the use of an appropriate Jackson
derivative and q-integral. Moreover, we derive the most important thermodynamic
functions and we study the q-boson and q-fermion ideal gas in the thermodynamic
limit.Comment: 14 pages, 2 figure
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