In vivo nuclear magnetic resonance imaging

A number of physiological changes have been demonstrated in bone, muscle and blood after exposure of humans and animals to microgravity. Determining mechanisms and the development of effective countermeasures for long duration space missions is an important NASA goal. The advent of tomographic nuclear magnetic resonance imaging (NMR or MRI) gives NASA a way to greatly extend early studies of this phenomena in ways not previously possible; NMR is also noninvasive and safe. NMR provides both superb anatomical images for volume assessments of individual organs and quantification of chemical/physical changes induced in the examined tissues. The feasibility of NMR as a tool for human physiological research as it is affected by microgravity is demonstrated. The animal studies employed the rear limb suspended rat as a model of mucle atrophy that results from microgravity. And bedrest of normal male subjects was used to simulate the effects of microgravity on bone and muscle

Burnout-depression overlap: A study of New Zealand schoolteachers

We examined the overlap of burnout with depression in a sample of 184 New Zealand schoolteachers. Burnout and depressive symptoms were strongly correlated with each other (r = .73; disattenuated correlation: .82) and moderately correlated with dysfunctional attitudes, ruminative responses, and pessimistic attributions. All the participants with high frequencies of burnout symptoms were identified as clinically depressed. Suicidal ideation was reported by 36% of those participants. Three groups of teachers emerged from a two-step cluster analysis: “low burnout-depression,” “medium burnout-depression,” and “high burnout-depression.” The correlation between the affective-cognitive and somatic symptoms of depression was similar in strength to the burnout-depression correlation. Consistent with recent results obtained in Europe and the U.S., our findings suggest that burnout is a depressive syndrome

Minor physical anomalies: Modifiers of environmental risk for psychopathology

Tested the hypothesis that minor physical anomalies (MPAs) modify an adolescent\u27s vulnerability to environmental risk factors for psychopathology. 118 male 17-yr-olds who had been evaluated as 7-year-olds received a comprehensive neuropsychiatric evaluation. The evaluation included standardized assessments of environmental risk factors for psychiatric impairment, neurological signs, IQ, MPAs, and psychiatric impairment. The relationship between psychiatric status and environmental risk was examined as a function of the MPA profile. There was a significant interaction between MPAs and environmental risk in predicting psychiatric status. Environmental risk was more predictive of psychiatric impairment at age 17 in Ss with high scores on the MPA scale than in Ss with low scores on the scale. This relationship was particularly apparent in Ss with conduct disorder. MPAs also exhibited relationships with 2 childhood factors, neurological soft signs and Verbal IQ, that had been shown to predict adolescent psychopathology in prior reports on this cohort

Two-Stage Friend Recommendation Based on Network Alignment and Series Expansion of Probabilistic Topic Model

© 2017 IEEE. Precise friend recommendation is an important problem in social media. Although most social websites provide some kinds of auto friend searching functions, their accuracies are not satisfactory. In this paper, we propose a more precise auto friend recommendation method with two stages. In the first stage, by utilizing the information of the relationship between texts and users, as well as the friendship information between users, we align different social networks and choose some "possible friends." In the second stage, with the relationship between image features and users, we build a topic model to further refine the recommendation results. Because some traditional methods, such as variational inference and Gibbs sampling, have their limitations in dealing with our problem, we develop a novel method to find out the solution of the topic model based on series expansion. We conduct experiments on the Flickr dataset to show that the proposed algorithm recommends friends more precisely and faster than traditional methods

Chern-simon type photon mass from fermion electric dipole moments at finite temperature in 3+1 dimensions

We study the low energy effective field theory of fermions with electric and magnetic dipole moments at finite temperature. We find that at one loop there is an interaction term of the Chern-Simon form ${\cal L_I}=m_\mu\>A_\nu {\tilde F}^{\mu\nu}$. The four vector $m_\mu \simeq d_i \mu_i m_i^2 ~{\partial_\mu}\>(ln T)$ is interpreted as a Chern- Simon type mass of photons, which is determined by the electric (magnetic) dipole moments $d_i$ ($\mu_i$) of the fermions in the vacuum polarisation loop diagram. The physical consequence of such a photon mass is that, photons of opposite circular polarisations, propagating through a hot medium, have different group velocities. We estimate that the time lag between the arrival times of the left and right circularly polarised light signals from pulsars. If the light propagates through a hot plasma (where the temperature in some regions is $T \sim 100 MeV$) then the time lag between the two circularly polarised signals of frequency $\omega$ will be $\Delta t(\omega) \simeq 10^{-6} /\omega$. It may be possible to observe this effect in pulsar signals which propagate through nebula at high temperatures.Comment: plain TeX, 9 page

Radiatively Induced Lorentz and CPT Violation in Electrodynamics

In a nonperturbative formulation, radiative corrections arising from Lorentz and CPT violation in the fermion sector induce a definite and nonzero Chern-Simons addition to the electromagnetic action. If instead a perturbative formulation is used, an infinite class of theories characterized by the value of the Chern-Simons coefficient emerges at the quantum level.Comment: 4 page

Free conical dynamics: charge-monopole as a particle with spin, anyon and nonlinear fermion-monopole supersymmetry

We discuss the origin of the effectively free dynamics of the charge in the magnetic monopole field to apply it for finding the alternative treatment of the charge-monopole as a particle with spin, for tracing out the relation of the charge-monopole to the free relativistic anyon and for clarifying the nature of the non-standard nonlinear supersymmetry of the fermion-monopole system.Comment: 8 pages, to be published in Nuclear Physics B Conference Supplements (D.V.Volkov Memorial Conference ``Supersymmetry and Quantum Field Theory'', Kharkov, July 25-29, 2000

Schr\"{o}dinger Fields on the Plane with non-Abelian Chern-Simons Interactions

Physical content of the nonrelativistic quantum field theory with non-Abelian Chern-Simons interactions is clarified with the help of the equivalent first- quantized description which we derive in any physical gauge.Comment: 12 pages, LaTex, SNUTP 94-1

Symmetries and classical quantization

A phenomenon of classical quantization is discussed. This is revealed in the class of pseudoclassical gauge systems with nonlinear nilpotent constraints containing some free parameters. Variation of parameters does not change local (gauge) and discrete symmetries of the corresponding systems, but there are some special discrete values of them which give rise to the maximal global symmetries at the classical level. Exactly the same values of the parameters are separated at the quantum level, where, in particular, they are singled out by the requirement of conservation of the discrete symmetries. The phenomenon is observed for the familiar pseudoclassical model of 3D P,T-invariant massive fermion system and for a new pseudoclassical model of 3D P,T-invariant system of topologically massive U(1) gauge fields.Comment: 10 pages, LaTe