388 research outputs found
Flexible matrix composite laminated disk/ring flywheel
An energy storage flywheel consisting of a quasi-isotropic composite disk overwrapped by a circumferentially wound ring made of carbon fiber and a elastometric matrix is proposed. Through analysis it was demonstrated that with an elastomeric matrix to relieve the radial stresses, a laminated disk/ring flywheel can be designed to store a least 80.3 Wh/kg or about 68% more than previous disk/ring designs. at the same time the simple construction is preserved
Decoupling social status and status certainty effects on health in macaques: a network approach.
BackgroundAlthough a wealth of literature points to the importance of social factors on health, a detailed understanding of the complex interplay between social and biological systems is lacking. Social status is one aspect of social life that is made up of multiple structural (humans: income, education; animals: mating system, dominance rank) and relational components (perceived social status, dominance interactions). In a nonhuman primate model we use novel network techniques to decouple two components of social status, dominance rank (a commonly used measure of social status in animal models) and dominance certainty (the relative certainty vs. ambiguity of an individual's status), allowing for a more complex examination of how social status impacts health.MethodsBehavioral observations were conducted on three outdoor captive groups of rhesus macaques (N = 252 subjects). Subjects' general physical health (diarrhea) was assessed twice weekly, and blood was drawn once to assess biomarkers of inflammation (interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and C-reactive protein (CRP)).ResultsDominance rank alone did not fully account for the complex way that social status exerted its effect on health. Instead, dominance certainty modified the impact of rank on biomarkers of inflammation. Specifically, high-ranked animals with more ambiguous status relationships had higher levels of inflammation than low-ranked animals, whereas little effect of rank was seen for animals with more certain status relationships. The impact of status on physical health was more straightforward: individuals with more ambiguous status relationships had more frequent diarrhea; there was marginal evidence that high-ranked animals had less frequent diarrhea.DiscussionSocial status has a complex and multi-faceted impact on individual health. Our work suggests an important role of uncertainty in one's social status in status-health research. This work also suggests that in order to fully explore the mechanisms for how social life influences health, more complex metrics of social systems and their dynamics are needed
Enrichissement en protéines du tourteau de coprah : sélection de champignons filamenteux en FMS = Protein enrichment of copra cake : selection of filamentous fungi in SSF
Les résultats ont montré que 11 souches sur 51 testées peuvent être retenues. Elles appartiennent aux espèces #Aspergillus sp., #Aspergillus niger, Penicillium italicum, Penicillium sp. et #Penicillium roquefortii$. Le rendement moyen d'enrichissement en protéines est de 20 %. Toutefois l'objectif n'est pas totalement atteint. Une optimisation des conditions de culture, en particulier, de la composition des milieux de culture, s'impose afin d'augmenter ces rendements protéiques et atteindre 50 %
Covariance properties and regularization of conserved currents in tetrad gravity
We discuss the properties of the gravitational energy-momentum 3-form within
the tetrad formulation of general relativity theory. We derive the covariance
properties of the quantities describing the energy-momentum content under
Lorentz transformations of the tetrad. As an application, we consider the
computation of the total energy (mass) of some exact solutions of Einstein's
general relativity theory which describe compact sources with asymptotically
flat spacetime geometry. As it is known, depending on the choice of tetrad
frame, the formal total integral for such configurations may diverge. We
propose a natural regularization method which yields finite values for the
total energy-momentum of the system and demonstrate how it works on a number of
explicit examples.Comment: 36 pages, Revtex, no figures; small changes, published versio
Quantum Time and Spatial Localization: An Analysis of the Hegerfeldt Paradox
Two related problems in relativistic quantum mechanics, the apparent
superluminal propagation of initially localized particles and dependence of
spatial localization on the motion of the observer, are analyzed in the context
of Dirac's theory of constraints. A parametrization invariant formulation is
obtained by introducing time and energy operators for the relativistic particle
and then treating the Klein-Gordon equation as a constraint. The standard,
physical Hilbert space is recovered, via integration over proper time, from an
augmented Hilbert space wherein time and energy are dynamical variables. It is
shown that the Newton-Wigner position operator, being in this description a
constant of motion, acts on states in the augmented space. States with strictly
positive energy are non-local in time; consequently, position measurements
receive contributions from states representing the particle's position at many
times. Apparent superluminal propagation is explained by noting that, as the
particle is potentially in the past (or future) of the assumed initial place
and time of localization, it has time to propagate to distant regions without
exceeding the speed of light. An inequality is proven showing the Hegerfeldt
paradox to be completely accounted for by the hypotheses of subluminal
propagation from a set of initial space-time points determined by the quantum
time distribution arising from the positivity of the system's energy. Spatial
localization can nevertheless occur through quantum interference between states
representing the particle at different times. The non-locality of the same
system to a moving observer is due to Lorentz rotation of spatial axes out of
the interference minimum.Comment: This paper is identical to the version appearing in J. Math. Phys.
41; 6093 (Sept. 2000). The published version will be found at
http://ojps.aip.org/jmp/. The paper (40 page PDF file) has been completely
revised since the last posting to this archiv
Circadian Behaviour in Neuroglobin Deficient Mice
Neuroglobin (Ngb), a neuron-specific oxygen-binding globin with an unknown function, has been proposed to play a key role in neuronal survival. We have previously shown Ngb to be highly expressed in the rat suprachiasmatic nucleus (SCN). The present study addresses the effect of Ngb deficiency on circadian behavior. Ngb-deficient and wild-type (wt) mice were placed in running wheels and their activity rhythms, endogenous period and response to light stimuli were investigated. The effect of Ngb deficiency on the expression of Period1 (Per1) and the immediate early gene Fos was determined after light stimulation at night and the neurochemical phenotype of Ngb expressing neurons in wt mice was characterized. Loss of Ngb function had no effect on overall circadian entrainment, but resulted in a significantly larger phase delay of circadian rhythm upon light stimulation at early night. A light-induced increase in Per1, but not Fos, gene expression was observed in Ngb-deficient mice. Ngb expressing neurons which co-stored Gastrin Releasing Peptide (GRP) and were innervated from the eye and the geniculo-hypothalamic tract expressed FOS after light stimulation. No PER1 expression was observed in Ngb-positive neurons. The present study demonstrates for the first time that the genetic elimination of Ngb does not affect core clock function but evokes an increased behavioural response to light concomitant with increased Per1 gene expression in the SCN at early night
A Systematic Review of Music Therapy Practice and Outcomes with Acute Adult Psychiatric In-Patients
PMCID: PMC3732280This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Network Dynamics Mediate Circadian Clock Plasticity
A circadian clock governs most aspects of mammalian behavior. Although its properties are in part genetically determined, altered light-dark environment can change circadian period length through a mechanism requiring de novo DNA methylation. We show here that this mechanism is mediated not via cell-autonomous clock properties, but rather through altered networking within the suprachiasmatic nuclei (SCN), the circadian “master clock,” which is DNA methylated in region-specific manner. DNA methylation is necessary to temporally reorganize circadian phasing among SCN neurons, which in turn changes the period length of the network as a whole. Interruption of neural communication by inhibiting neuronal firing or by physical cutting suppresses both SCN reorganization and period changes. Mathematical modeling suggests, and experiments confirm, that this SCN reorganization depends upon GABAergic signaling. Our results therefore show that basic circadian clock properties are governed by dynamic interactions among SCN neurons, with neuroadaptations in network function driven by the environment
Expression Analysis of PAC1-R and PACAP Genes in Zebrafish Embryos
This study describes the expression of the pituitary adenylate cyclase-activating polypeptide (PACAP1 and PACAP2) and PAC1 receptor genes (PAC1a-R and PAC1b-R) in the brain of zebrafish (Danio rerio) during development. In situ hybridization of the 24- and 48-hpf embryos revealed that PACAP genes were expressed in the telencephalon, the diencephalon, the rhombencephalon, and the neurons in the dorsal part of the spinal cord. PACAP2 mRNA appears to be the most abundant form during brain development. The two PAC1-R subtypes showed a similar expression pattern: mRNAs were detected in the forebrain, the thalamus, and the rhombencephalon. However, in the tectum, only PAC1b-R gene was detected. These results suggest that, in fish, PACAP may play a role in brain development
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