1,068 research outputs found
Logical inference approach to relativistic quantum mechanics: derivation of the Klein-Gordon equation
The logical inference approach to quantum theory, proposed earlier [Ann.
Phys. 347 (2014) 45-73], is considered in a relativistic setting. It is shown
that the Klein-Gordon equation for a massive, charged, and spinless particle
derives from the combination of the requirements that the space-time data
collected by probing the particle is obtained from the most robust experiment
and that on average, the classical relativistic equation of motion of a
particle holds
Photo-induced magnetization enhancement in two-dimensional weakly anisotropic Heisenberg magnets
By comparing the photo-induced magnetization dynamics in simple layered
systems we show how light-induced modifications of the magnetic anisotropy
directly enhance the magnetization. It is observed that the spin precession in
(CH3NH3)2CuCl4, initiated by a light pulse, increases in amplitude at the
critical temperature TC. The phenomenon is related to the dependence of the
critical temperature on the axial magnetic anisotropy. The present results
underline the possibility and the importance of the optical modifications of
the anisotropy, opening new paths toward the control of the magnetization state
for ultrafast memories.Comment: 5 pages, 3 figures, supplementary info as SIr.pd
A Quantitative Exploration of Two Teachers with Contrasting Emotions: Intra-Individual Process Analyses of Physiology and Interpersonal Behavior
Although the association between teacher-student relations, teacher emotions, and burnout has been proven on a general level, we do not know the exact processes underlying these associations. Recently there has been a call for intra-individual process measures that assess what happens from moment-to-moment in class in order to better understand inter-individual differences in emotions and burnout between teachers. This paper explored the use of process measures of teachers’ heart rate and their interpersonal behavior during teaching. Our aim was to illustrate different ways of analyzing and combining physiological and observational time-series data and to explore their potential for understanding between-teacher differences. In this illustration, we focused on two teachers who represented contrasting cases in terms of their self-reported teaching-related emotions (i.e., anxiety and relaxation) and burnout. We discuss both univariate process analyses (i.e., trend, autocorrelation, stability) as well as state-of-the-art multivariate process analyses (i.e., cross-correlations, dynamic structural equation modeling). Results illustrate how the two teachers differed in the nature of their physiological responses, their interpersonal behavior, and the association between these two process measures over time. Along implications and suggestions for further research, it is discussed how the process-based, dynamic assessment of physiology and interpersonal behavior may ultimately help to understand differences in more general teaching-related emotions and burnout
Phonon and crystal field excitations in geometrically frustrated rare earth titanates
The phonon and crystal field excitations in several rare earth titanate
pyrochlores are investigated. Magnetic measurements on single crystals of
Gd2Ti2O7, Tb2Ti2O7, Dy2Ti2O7 and Ho2Ti2O7 are used for characterization, while
Raman spectroscopy and terahertz time domain spectroscopy are employed to probe
the excitations of the materials. The lattice excitations are found to be
analogous across the compounds over the whole temperature range investigated
(295-4 K). The resulting full phononic characterization of the R2Ti2O7
pyrochlore structure is then used to identify crystal field excitations
observed in the materials. Several crystal field excitations have been observed
in Tb2Ti2O7 in Raman spectroscopy for the first time, among which all of the
previously reported excitations. The presence of additional crystal field
excitations, however, suggests the presence of two inequivalent Tb3+ sites in
the low temperature structure. Furthermore, the crystal field level at
approximately 13 cm-1 is found to be both Raman and dipole active, indicating
broken inversion symmetry in the system and thus undermining its current
symmetry interpretation. In addition, evidence is found for a significant
crystal field-phonon coupling in Tb2Ti2O7. These findings call for a careful
reassessment of the low temperature structure of Tb2Ti2O7, which may serve to
improve its theoretical understanding.Comment: 13 pages, 7 figure
Multinomial belief networks for healthcare data
Healthcare data from patient or population cohorts are often characterized by
sparsity, high missingness and relatively small sample sizes. In addition,
being able to quantify uncertainty is often important in a medical context. To
address these analytical requirements we propose a deep generative Bayesian
model for multinomial count data. We develop a collapsed Gibbs sampling
procedure that takes advantage of a series of augmentation relations, inspired
by the Zhou\unicode{x2013}Cong\unicode{x2013}Chen model. We visualise the
model's ability to identify coherent substructures in the data using a dataset
of handwritten digits. We then apply it to a large experimental dataset of DNA
mutations in cancer and show that we can identify biologically meaningful
clusters of mutational signatures in a fully data-driven way.Comment: 18 pages, 4 figs; supplement: 22 page
Predictors and moderators of response to internet-delivered Interpersonal Psychotherapy and Cognitive Behavior Therapy for depression
Background: By identifying which predictors and moderators lead to beneficial outcomes, accurate selection of the best initial treatment will have significant benefits for depressed individuals.
Method: An automated, fully self guided randomized controlled internet-delivered noninferiority trial was conducted comparing two new interventions (Interpersonal Psychotherapy [IPT; n=620] and Cognitive Behavioral Therapy [CBT; n=610]) to an active control intervention (MoodGYM; n=613) over a period of 4 weeks to spontaneous visitors of an internet-delivered therapy vvebsite (e couch). A range of putative predictors and moderators (socio-demographic characteristics [age, gender, marital status, education level], clinical characteristics [depression/anxiety symptoms, disability, quality of life, medication use], skills [mastery and dysfunctional attitudes] and treatment preference) were assessed using internet-delivered self-report measures at baseline and immediately following treatment and at six months follow-up. Analyses were conducted using Mixed Model Repeated Measures (MMRM).
Results: Female gender, lower mastery and lower dysfunctional attitudes predicted better outcome at post-test and/or follow-up regardless of intervention. No overall differential effects for condition On depression as a function of outcome were found. However, based on time-specific estimates, a significant interaction effect of age was found. For younger people, intemet-delivered IPT may be the preferred treatment choice, whereas older participants derive more benefits from internet-delivered CBT programs.
Limitations: Although the sample of participants was large, power to detect moderator effects was still lacking.
Conclusions: Different e-mental health programs may be more beneficial for specific age groups. The Findings raise important possibilities for increasing depression treatment effectiveness and improving clinical practice guidelines for depression treatment of different age groups. (C) 2013 Elsevier B.V. All rights reserved
Genetic mechanisms of pollution resistance in a marine invertebrate
Pollution is a common stress in the marine environment and one of today's most powerful agents of selection, yet we have little understanding of how anthropogenic toxicants influence mechanisms of adaptation in marine populations. Due to their life history strategies, marine invertebrates are unable to avoid stress and must adapt to variable environments. We examined the genetic basis of pollution resistance across multiple environments using the marine invertebrate, Styela plicata. Gametes were crossed in a quantitative genetic breeding design to enable partitioning of additive genetic variance across a concentration gradient of a common marine pollutant, copper. Hatching success was scored as a measure of stress resistance in copper concentrations of 0, 75, 150, and 350 mu g/L. There was a significant genotype 3 environment interaction in hatching success across copper concentrations. Further analysis using factor analytic modeling confirmed a significant dimension of across-environment genetic variation where the genetic basis of resistance to stress in the first three environments differed from that in the environment of highest copper concentration. A second genetic dimension further differentiated between the genetic basis of resistance to low and high stress environments. These results suggest that marine organisms use different genetic mechanisms to adapt to different levels of pollution and that the level of genetic variation to adapt to intense pollution stresses may be limited
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