1,723 research outputs found
Investigation of nonlinear interaction phenomena in the ionosphere
Ionospheric phenomena as thermal radiation noise, propagation of naturally occurring radio noise through ionosphere, and generation of very low frequency emission
Demographic Impacts in IT Education: Research Agendas.
Culture impacts upon use, useability and decision-making processes that surround Information Technology (IT). Radical changes in the demographic profile of New Zealand cause us to reflect on the impact of such changes, as the underlying culture of the country must change with the demographic changes. This process gives rise to some interesting questions, including whether we still accept Hofstede’s analysis of New Zealand as an individualistic country. Pacifika, Asian and Maori are collectivist cultures. One important question is what impact do demographic changes have on educational requirements, given that Maori experience of IT differs from mainstream New Zealand, and given that Maori and other collective cultures form an increasing proportion of the population, particularly in Auckland
A feynman path integral representation for elastic wave scattering by anisotropic weakly perturbations
We write a space-time Feynman path integral representation for scattered
elastic wave fields from a weakly compact supported anisotropic
non-homogeneity.Replacement by a new version where We (I!) propose a new
tomographic inversion methodology based solely in the wave sampling of the Ray
paths through Monte Carlo path integral sampling Holding thus great
potentiality for Navy's advanced Sonar detection .Comment: 8 page
Mechanical Systems: Symmetry and Reduction
Reduction theory is concerned with mechanical systems with symmetries. It constructs a
lower dimensional reduced space in which associated conservation laws are taken out and
symmetries are \factored out" and studies the relation between the dynamics of the given
system with the dynamics on the reduced space. This subject is important in many areas,
such as stability of relative equilibria, geometric phases and integrable systems
Finding middle ground between intellectual arrogance and intellectual servility: Development and assessment of the limitations-owning intellectual humility scale
Recent scholarship in intellectual humility (IH) has attempted to provide deeper understanding of the virtue as personality trait and its impact on an individual's thoughts, beliefs, and actions. A limitations-owning perspective of IH focuses on a proper recognition of the impact of intellectual limitations and a motivation to overcome them, placing it as the mean between intellectual arrogance and intellectual servility. We developed the Limitations-Owning Intellectual Humility Scale to assess this conception of IH with related personality constructs. In Studies 1 (n= 386) and 2 (n = 296), principal factor and confirmatory factor analyses revealed a three-factor model – owning one's intellectual limitations, appropriate discomfort with intellectual limitations, and love of learning. Study 3 (n = 322) demonstrated strong test-retest reliability of the measure over 5 months, while Study 4 (n = 612) revealed limitations-owning IH correlated negatively with dogmatism, closed-mindedness, and hubristic pride and positively with openness, assertiveness, authentic pride. It also predicted openness and closed-mindedness over and above education, social desirability, and other measures of IH. The limitations-owning understanding of IH and scale allow for a more nuanced, spectrum interpretation and measurement of the virtue, which directs future study inside and outside of psychology
Investigating the origin and transport of methylated arsenic species in plants
Inorganic arsenic is a toxic element known to cause various diseases and cancers in humans. Arsenic contamination is widespread worldwide, particularly in South-East Asia where arsenic-contaminated groundwater is used for drinking and rice cultivation. Unlike other cereals, paddy rice can efficiently accumulate arsenic in the grain. Rice is a staple food for around 50% of the world's population, so arsenic accumulation in rice is of great concern. Arsenite, As(III), is the predominant form of arsenic within plants, but rice grains often contain significant proportions of organic arsenic species. The most common of these are dimethylarsinic acid (DMA) and monomethylarsonic acid (MMA). A series of axenic experiments demonstrated that plants are unable to methylate arsenic, and instead take these species up from soil where they are produced by micro-organisms. The uptake of undissociated MMA by rice roots is predominantly facilitated by OsNIP2;1 (OsLsi1), a member of the NIP-subfamily of aquaporins, which also accounts for 50% of root DMA uptake. Expression of OsNIP1;1 and OsNIP3;3 in Xenopus oocytes demonstrated that these NIP aquaporins are permeable to pentavalent MMA, as well as arsenite, silicon and water. However, uptake of DMA was not observed for oocytes expressing any NIP gene, including OsNIP2;1. MMA and DMA have a pKa1 of 4.19 and 6.14 respectively, and so increasing the pH of the medium increases the proportion of dissociated complexes. In hydroponic culture, rice plants over-expressing the high-affinity phosphate transporter OsPT8, took up significantly more MMA and DMA than wild-type. Additionally, the presence of phosphate in the medium significantly decreased the uptake of both MMA and DMA by OsPT8-overexpression and wild-type rice plants. Therefore we have discovered that methylated arsenic species are not formed within plants, and can be transported by two different classes of transporters depending on the pH of the medium
Geometric and dynamic perspectives on phase-coherent and noncoherent chaos
Statistically distinguishing between phase-coherent and noncoherent chaotic
dynamics from time series is a contemporary problem in nonlinear sciences. In
this work, we propose different measures based on recurrence properties of
recorded trajectories, which characterize the underlying systems from both
geometric and dynamic viewpoints. The potentials of the individual measures for
discriminating phase-coherent and noncoherent chaotic oscillations are
discussed. A detailed numerical analysis is performed for the chaotic R\"ossler
system, which displays both types of chaos as one control parameter is varied,
and the Mackey-Glass system as an example of a time-delay system with
noncoherent chaos. Our results demonstrate that especially geometric measures
from recurrence network analysis are well suited for tracing transitions
between spiral- and screw-type chaos, a common route from phase-coherent to
noncoherent chaos also found in other nonlinear oscillators. A detailed
explanation of the observed behavior in terms of attractor geometry is given.Comment: 12 pages, 13 figure
Radiation therapy planning with photons and protons for early and advanced breast cancer: an overview
Postoperative radiation therapy substantially decreases local relapse and moderately reduces breast cancer mortality, but can be associated with increased late mortality due to cardiovascular morbidity and secondary malignancies. Sophistication of breast irradiation techniques, including conformal radiotherapy and intensity modulated radiation therapy, has been shown to markedly reduce cardiac and lung irradiation. The delivery of more conformal treatment can also be achieved with particle beam therapy using protons. Protons have superior dose distributional qualities compared to photons, as dose deposition occurs in a modulated narrow zone, called the Bragg peak. As a result, further dose optimization in breast cancer treatment can be reasonably expected with protons. In this review, we outline the potential indications and benefits of breast cancer radiotherapy with protons. Comparative planning studies and preliminary clinical data are detailed and future developments are considered
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