6,009 research outputs found
Large magnetic circular dichroism in resonant inelastic x-ray scattering at the Mn L-edge of Mn-Zn ferrite
We report resonant inelastic x-ray scattering (RIXS) excited by circularly
polarized x-rays on Mn-Zn ferrite at the Mn L2,3-resonances. We demonstrate
that crystal field excitations, as expected for localized systems, dominate the
RIXS spectra and thus their dichroic asymmetry cannot be interpreted in terms
of spin-resolved partial density of states, which has been the standard
approach for RIXS dichroism. We observe large dichroic RIXS at the L2-resonance
which we attribute to the absence of metallic core hole screening in the
insulating Mn-ferrite. On the other hand, reduced L3-RIXS dichroism is
interpreted as an effect of longer scattering time that enables spin-lattice
core hole relaxation via magnons and phonons occurring on a femtosecond time
scale.Comment: 7 pages, 2 figures,
http://link.aps.org/doi/10.1103/PhysRevB.74.17240
A Non-Sequential Representation of Sequential Data for Churn Prediction
We investigate the length of event sequence giving best predictions
when using a continuous HMM approach to churn prediction from sequential
data. Motivated by observations that predictions based on only the few most recent
events seem to be the most accurate, a non-sequential dataset is constructed
from customer event histories by averaging features of the last few events. A simple
K-nearest neighbor algorithm on this dataset is found to give significantly
improved performance. It is quite intuitive to think that most people will react
only to events in the fairly recent past. Events related to telecommunications occurring
months or years ago are unlikely to have a large impact on a customer’s
future behaviour, and these results bear this out. Methods that deal with sequential
data also tend to be much more complex than those dealing with simple nontemporal
data, giving an added benefit to expressing the recent information in a
non-sequential manner
Research and applications: Artificial intelligence
The program is reported for developing techniques in artificial intelligence and their application to the control of mobile automatons for carrying out tasks autonomously. Visual scene analysis, short-term problem solving, and long-term problem solving are discussed along with the PDP-15 simulator, LISP-FORTRAN-MACRO interface, resolution strategies, and cost effectiveness
Magnetic circular dichroism in X-ray fluorescence of Heusler alloys at threshold excitation
The results of fluorescence measurements of magnetic circular dichroism (MCD)
in Mn L_2,L_3 X-ray emission and absorption for Heusler alloys NiMnSb and
Co2MnSb are presented. Very intense resonance Mn L_3 emission is found at the
Mn 2p_3/2 threshold and is attributed to a peculiarity of the threshold
excitation in materials with the half-metallic character of the electronic
structure. A theoretical model for the description of resonance scattering of
polarized x-rays is suggested.Comment: 3 pages, 2 figures. Discussed at conferences, submitting process in
progres
Effects of a standard provision versus an autonomy supportive exercise referral programme on physical activity, quality of life and well-being indicators:a cluster randomised controlled trial
Background: The National Institute for Health and Clinical Excellence in the UK has recommended that the effectiveness of ongoing exercise referral schemes to promote physical activity should be examined in research trials. Recent empirical evidence in health care and physical activity promotion contexts provides a foundation for testing the feasibility and impact of a Self Determination Theory-based (SDT) exercise referral consultation. Methods: An exploratory cluster randomised controlled trial comparing standard provision exercise referral with an exercise referral intervention grounded in Self Determination Theory. Individuals (N = 347) referred to an exercise referral scheme were recruited into the trial from 13 centres. Outcomes and processes of change measured at baseline, 3 and 6-months: Minutes of self-reported moderate or vigorous physical activity (PA) per week (primary outcome), health status, positive and negative indicators of emotional well-being, anxiety, depression, quality of life (QOL), vitality, and perceptions of autonomy support from the advisor, need satisfaction (3 and 6 months only), intentions to be active, and motivational regulations for exercise. Blood pressure and weight were assessed at baseline and 6 months.Results: Perceptions of the autonomy support provided by the health and fitness advisor (HFA) did not differ by arm. Between group changes over the 6-months revealed significant differences for reported anxiety only. Within arm contrasts revealed significant improvements in anxiety and most of the Dartmouth CO-OP domains in the SDT arm at 6 months, which were not seen in the standard exercise referral group. A process model depicting hypothesized relationships between advisor autonomy support, need satisfaction and more autonomous motivation, enhanced well being and PA engagement at follow up was supported. Conclusions: Significant gains in physical activity and improvements in quality of life and well-being outcomes emerged in both the standard provision exercise referral and the SDT-based intervention at programme end. At 6-months, observed between arm and within intervention arm differences for indicators of emotional health, and the results of the process model, were in line with SDT. The challenges in optimising recruitment and implementation of SDT-based training in the context of health and leisure services are discussed
Setting the stage: social-environmental and motivational predictors of optimal training engagement
In this paper, we will firstly explore the central tenets of SDT. Research that has examined the social-environmental and motivation-related correlates of optimal training, performance and health-related engagement through the theoretical lens of SDT will be reviewed. Drawing from SDT-driven work undertaken in educational, sport and dance settings, we will draw conclusions and suggest future directions from a research and applied perspective
Avaliacao genetica e selecao em Eucalyptus grandis na regiao de Arapoti - PR.
Foram avaliados 17.916 indivíduos, pertencentes a 163 progênies de polinização aberta de 11 populações de Eucalyptus grandis, implantadas em duas fazendas na região de Arapoti - PR, visando a seleção de indivíduos com base em seus valores genéticos preditos. Foram obtidas estimativas médias da herdabilidade no sentido restrito, em nível de indivíduos e da acurácia seletiva, da ordem de 40 e 65%, respectivamente. A estimativa (0,75) da correlação genética entre médias de progênies, nas duas fazendas, indicou que a interação genótipo X ambiente não é problemática para o melhorista. Ganhos genéticos da ordem de 87 a 105% poderão ser obtidos com o estabelecimento das populações de melhoramento e de produção de sementes, respectivamente
Resonant X-Ray Raman Spectra of Cu dd Excitations in Sr2CuO2Cl2
We present resonant x-ray Raman scattering results on Sr2CuO2Cl2, a model compound for high-Tc
superconductors. We demonstrate that the dd excitations can be observed and show that the polarization
dependence can be used to identify the dd excitations. We find the transition from the dx²-y² ground
state to the dxy excited state at 1.35 eV and to the degenerate dxz and dyz excited states at 1.7 eV. From
analysis of the polarization dependence we conclude that the d3z²-r² orbital energy is at 1.5 eV and not
in the midinfrared (0.5 eV) as recently suggested. We use recent theoretical arguments to show that
the d3z22r2 excitation is accompanied by a local spin flip resulting in a shift upwards of 0.2 eV due to
the exchange interaction with the neighboring spins
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