320 research outputs found
New battery model and state-of-health determination through subspace parameter estimation and state-observer techniques
This paper describes a novel adaptive battery model based on a remapped variant of the well-known Randles' lead-acid model. Remapping of the model is shown to allow improved modeling capabilities and accurate estimates of dynamic circuit parameters when used with subspace parameter-estimation techniques. The performance of the proposed methodology is demonstrated by application to batteries for an all-electric personal rapid transit vehicle from the Urban Light TRAnsport (ULTRA) program, which is designated for use at Heathrow Airport, U. K. The advantages of the proposed model over the Randles' circuit are demonstrated by comparisons with alternative observer/estimator techniques, such as the basic Utkin observer and the Kalman estimator. These techniques correctly identify and converge on voltages associated with the battery state-of-charge (SoC), despite erroneous initial conditions, thereby overcoming problems attributed to SoC drift (incurred by Coulomb-counting methods due to overcharging or ambient temperature fluctuations). Observation of these voltages, as well as online monitoring of the degradation of the estimated dynamic model parameters, allows battery aging (state-of-health) to also be assessed and, thereby, cell failure to be predicted. Due to the adaptive nature of the proposed algorithms, the techniques are suitable for applications over a wide range of operating environments, including large ambient temperature variations. Moreover, alternative battery topologies may also be accommodated by the automatic adjustment of the underlying state-space models used in both the parameter-estimation and observer/estimator stages
Changes in self-reported pre- to postinjury coping styles in the first 3 years after traumatic brain injury and the effects on psychosocial and emotional functioning and quality of life
OBJECTIVE:: To examine the influence of self-reported preinjury coping on postinjury coping, psychosocial functioning, emotional functioning, and quality of life at 1 year following traumatic brain injury (TBI). SETTING:: Inpatient hospital and community. PARTICIPANTS:: One hundred seventy-four participants with TBI. DESIGN:: Prospective, longitudinal design. Participants were assessed at 5 time points: after emerging from posttraumatic amnesia, and at 6, 12, 24, and 36 months postinjury. MAIN MEASURES:: Coping Scale for Adults-Short Version; Quality of Life Inventory; Sydney Psychosocial Reintegration Scale; Hospital Anxiety and Depression Scale. RESULTS:: High preinjury use of nonproductive coping style predicted high use of nonproductive coping, more anxiety, and lower psychosocial functioning at 1 year postinjury. Increased use of nonproductive coping and decreased use of productive coping predicted poorer psychosocial outcome at 1 year post-TBI. Use of both productive and nonproductive coping decreased in the first 6 to 12 months post-TBI relative to preinjury. Unlike productive coping, nonproductive coping reached preinjury levels within 3 years postinjury. CONCLUSION:: The findings support identification of individuals at risk of relying on nonproductive coping and poorer psychosocial outcome following TBI. In addition, the results emphasize the need to implement timely interventions to facilitate productive coping and reduce the use of nonproductive coping in order to maximize favorable long-term psychosocial outcome
Calculation of NMR Properties of Solitons in Superfluid 3He-A
Superfluid 3He-A has domain-wall-like structures, which are called solitons.
We calculate numerically the structure of a splay soliton. We study the effect
of solitons on the nuclear-magnetic-resonance spectrum by calculating the
frequency shifts and the amplitudes of the soliton peaks for both longitudinal
and transverse oscillations of magnetization. The effect of dissipation caused
by normal-superfluid conversion and spin diffusion is calculated. The
calculations are in good agreement with experiments, except a problem in the
transverse resonance frequency of the splay soliton or in magnetic-field
dependence of reduced resonance frequencies.Comment: 15 pages, 10 figures, updated to the published versio
Soliton-like Spin State in the A-like Phase of 3He in Anisotropic Aerogel
We have found a new stable spin state in the A-like phase of superfluid 3He
confined to intrinsically anisotropic aerogel. The state can be formed by
radiofrequency excitation applied while cooling through the superfluid
transition temperature and its NMR properties are different from the standard
A-like phase obtained in the limit of very small excitation. It is possible
that this new state is formed by textural domain walls pinned by aerogel.Comment: 9 pages, 3 figures. Submitted to J. of Low Tem. Phys. (QFS2007
Proceedings
Punctuated equilibria and 1/f noise in a biological coevolution model with individual-based dynamics
We present a study by linear stability analysis and large-scale Monte Carlo
simulations of a simple model of biological coevolution. Selection is provided
through a reproduction probability that contains quenched, random interspecies
interactions, while genetic variation is provided through a low mutation rate.
Both selection and mutation act on individual organisms. Consistent with some
current theories of macroevolutionary dynamics, the model displays
intermittent, statistically self-similar behavior with punctuated equilibria.
The probability density for the lifetimes of ecological communities is well
approximated by a power law with exponent near -2, and the corresponding power
spectral densities show 1/f noise (flicker noise) over several decades. The
long-lived communities (quasi-steady states) consist of a relatively small
number of mutualistically interacting species, and they are surrounded by a
``protection zone'' of closely related genotypes that have a very low
probability of invading the resident community. The extent of the protection
zone affects the stability of the community in a way analogous to the height of
the free-energy barrier surrounding a metastable state in a physical system.
Measures of biological diversity are on average stationary with no discernible
trends, even over our very long simulation runs of approximately 3.4x10^7
generations.Comment: 20 pages RevTex. Minor revisions consistent with published versio
Neutrino Interferometry In Curved Spacetime
Gravitational lensing introduces the possibility of multiple (macroscopic)
paths from an astrophysical neutrino source to a detector. Such a multiplicity
of paths can allow for quantum mechanical interference to take place that is
qualitatively different to neutrino oscillations in flat space. After an
illustrative example clarifying some under-appreciated subtleties of the phase
calculation, we derive the form of the quantum mechanical phase for a neutrino
mass eigenstate propagating non-radially through a Schwarzschild metric. We
subsequently determine the form of the interference pattern seen at a detector.
We show that the neutrino signal from a supernova could exhibit the
interference effects we discuss were it lensed by an object in a suitable mass
range. We finally conclude, however, that -- given current neutrino detector
technology -- the probability of such lensing occurring for a
(neutrino-detectable) supernova is tiny in the immediate future.Comment: 25 pages, 1 .eps figure. Updated version -- with simplified notation
-- accepted for publication in Phys.Rev.D. Extra author adde
Effects of Aronia melanocarpa fruit juice on exploratory behaviour and locomotor activity in rats
The main bioactive substances in Aronia melanocarpa fruit juice (AMFJ) are polyphenols (flavonoids, procyanidins, and phenolic acids). A great number of polyphenols are able to traverse the blood-brain barrier. In recent years more attention is drawn to the ability of these substances to influence central nervous system functions. The aim of the present study was to investigate the effects of AMFJ on exploratory behaviour and locomotor activity in male Wistar rats. AMFJ was administered orally for 7, 14, 21, and 30 days at three increasing doses (2.5, 5, and 10 ml kgâ1). The changes in exploratory behaviour and locomotor activity were recorded in an Opto Varimex apparatus. It was found that the low doses of AMFJ (2.5 and 5 ml kgâ1) for all treatment periods did not significantly affect exploratory behaviour and locomotor activity of rats compared to the saline-treated controls. AMFJ at the highest dose of 10 ml kgâ1 had no significant effect on exploration and locomotion for the treatment periods of 7 and 14 days, while for the periods of 21 and 30 days it significantly decreased the number of horizontal and vertical movements, which might be the result of a sedative effect. At all the doses and testing periods, AMFJ did not disturb the progressive decrease in motor behaviour, suggesting habituation
Atomic diffraction from nanostructured optical potentials
We develop a versatile theoretical approach to the study of cold-atom
diffractive scattering from light-field gratings by combining calculations of
the optical near-field, generated by evanescent waves close to the surface of
periodic nanostructured arrays, together with advanced atom wavepacket
propagation on this optical potential.Comment: 8 figures, 10 pages, submitted to Phys. Rev.
DNA methylation is required to maintain both DNA replication timing precision and 3D genome organization integrity
DNA replication timing and three-dimensional (3D) genome organization are associated with distinct epigenome patterns across large domains. However, whether alterations in the epigenome, in particular cancer-related DNA hypomethylation, affects higher-order levels of genome architecture is still unclear. Here, using Repli-Seq, single-cell Repli-Seq, and Hi-C, we show that genome-wide methylation loss is associated with both concordant loss of replication timing precision and deregulation of 3D genome organization. Notably, we find distinct disruption in 3D genome compartmentalization, striking gains in cell-to-cell replication timing heterogeneity and loss of allelic replication timing in cancer hypomethylation models, potentially through the gene deregulation of DNA replication and genome organization pathways. Finally, we identify ectopic H3K4me3-H3K9me3 domains from across large hypomethylated domains, where late replication is maintained, which we purport serves to protect against catastrophic genome reorganization and aberrant gene transcription. Our results highlight a potential role for the methylome in the maintenance of 3D genome regulation
Red Queen Coevolution on Fitness Landscapes
Species do not merely evolve, they also coevolve with other organisms.
Coevolution is a major force driving interacting species to continuously evolve
ex- ploring their fitness landscapes. Coevolution involves the coupling of
species fit- ness landscapes, linking species genetic changes with their
inter-specific ecological interactions. Here we first introduce the Red Queen
hypothesis of evolution com- menting on some theoretical aspects and empirical
evidences. As an introduction to the fitness landscape concept, we review key
issues on evolution on simple and rugged fitness landscapes. Then we present
key modeling examples of coevolution on different fitness landscapes at
different scales, from RNA viruses to complex ecosystems and macroevolution.Comment: 40 pages, 12 figures. To appear in "Recent Advances in the Theory and
Application of Fitness Landscapes" (H. Richter and A. Engelbrecht, eds.).
Springer Series in Emergence, Complexity, and Computation, 201
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