2,179 research outputs found
Stability and Dynamics of Cross Solitons in Harmonically Confined Bose-Einstein Condensates
We examine the stability and dynamics of a family of crossed dark solitons in
a harmonically confined Bose-Einstein condensate in two dimensions. Working in
a regime where the fundamental snake instability is suppressed, we show the
existence of an instability which leads to an interesting collapse and revival
of the initial state for the fundamental case of two crossed solitons. The
instability originates from the singular point where the solitons cross, and we
characterise it by examining the Bogoliubov spectrum. Finally, we extend the
treatment to systems of higher symmetry.Comment: 7 pages, 7 figure
Using adiabatic coupling techniques in atom-chip waveguide structures
Adiabatic techniques are well known tools in multi-level electron systems to
transfer population between different states with high fidelity. Recently it
has been realised that these ideas can also be used in ultra-cold atom systems
to achieve coherent manipulation of the atomic centre-of-mass states. Here we
present an investigation into a realistic setup using three atomic waveguides
created on top of an atom chip and show that such systems hold large potential
for the observation of adiabatic phenomena in experiments.Comment: 10 pages, 6 figures, accepted for publication in Physica Scripta for
the CEWQO2009 proceeding
Identification of the slow E3 transition 136mCs -> 136Cs with conversion electrons
We performed at ISOLDE the spectroscopy of the decay of the 8- isomer in
136Cs by and conversion-electron detection. For the first time the excitation
energy of the isomer and the multipolarity of its decay have been measured. The
half-life of the isomeric state was remeasured to T1/2 = 17.5(2) s. This isomer
decays via a very slow 518 keV E3 transition to the ground state. In addition
to this, a much weaker decay branch via a 413 keV M4 and a subsequent 105 keV
E2 transition has been found. Thus we have found a new level at 105 keV with
spin 4+ between the isomeric and the ground state. The results are discussed in
comparison to shell model calculations.Comment: Phys. Rev. C accepted for publicatio
Using telehealth to support end of life care in the community: a feasibility study.
BACKGROUND: Telehealth is being used increasingly in providing care to patients in the community setting. Telehealth enhanced service delivery could offer new ways of managing load and care prioritisation for palliative care patients living in the community. The study assesses the feasibility of a telehealth-based model of service provision for community based palliative care patients, carers and clinicians. METHODS: This study was a prospective cohort study of a telehealth-based intervention for community based patients of a specialist palliative care service living in Southern Adelaide, South Australia. Participants were 43 community living patients enrolled in the Southern Adelaide Palliative Service. To be eligible patients needed to be over 18 years and have an Australian modified Karnofksy Performance Score > 40. Exclusion criteria included a demonstrated inability to manage the hardware or technology (unless living with a carer who could manage the technology) or non-English speaking without a suitable carer/proxy. Participants received video-based conferences between service staff and the patient/carer; virtual case conferences with the patient/carer, service staff and patient's general practitioner (GP); self-report assessment tools for patient and carer; and remote activity monitoring (ACTRN12613000733774). RESULTS: The average age of patients was 71.6 years (range: 49 to 91 years). All 43 patients managed to enter data using the telehealth system. Self-reported data entered by patients and carers did identify changes in performance status leading to changes in care. Over 4000 alerts were generated. Staff reported that videocalls were similar (22.3%) or better/much better (65.2%) than phone calls and similar (63.1%) or better/much better (27.1%) than face-to-face. Issues with the volume of alerts generated, technical support required and the impact of service change were identified. CONCLUSIONS: The trial showed that patients and carers could manage the technology and provide data that would otherwise not have been available to the palliative care service. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12613000733774 registered on 02/07/2013
First identification of large electric monopole strength in well-deformed rare earth nuclei
Excited states in the well-deformed rare earth isotopes Sm and
Er were populated via ``safe'' Coulomb excitation at the Munich MLL
Tandem accelerator. Conversion electrons were registered in a cooled Si(Li)
detector in conjunction with a magnetic transport and filter system, the
Mini-Orange spectrometer. For the first excited state in Sm at
1099 keV a large value of the monopole strength for the transition to the
ground state of could be extracted. This confirms the interpretation of the lowest
excited state in Sm as the collective -vibrational
excitation of the ground state. In Er the measured large electric
monopole strength of clearly identifies the state at 1934 keV to be the
-vibrational excitation of the ground state.Comment: submitted to Physics Letters
Electroencephalogram variability in patients with cirrhosis associates with the presence and severity of hepatic encephalopathy
BACKGROUND & AIMS: The outputs of physiological systems fluctuate in a complex manner even under resting conditions. Decreased variability or increased regularity of these outputs is documented in several disease states. Changes are observed in the spatial and temporal configuration of the electroencephalogram (EEG) in patients with hepatic encephalopathy (HE), but there is no information on the variability of the EEG signal in this condition. The aim of this study was to measure and characterize EEG variability in patients with cirrhosis and to determine its relationship to neuropsychiatric status. METHODS: Eyes-closed, awake EEGs were obtained from 226 patients with cirrhosis, classified, using clinical and psychometric criteria, as neuropsychiatrically unimpaired (n=127) or as having minimal (n=21) or overt (n=78) HE, and from a reference population of 137 healthy controls. Analysis of EEG signal variability was undertaken using continuous wavelet transform and sample entropy. RESULTS: EEG variability was reduced in the patients with cirrhosis compared with the reference population (coefficient of variation: 21.2% [19.3-23.4] vs. 22.4% [20.8-24.5]; p<0.001). A significant association was observed between EEG variability and neuropsychiatric status; thus, variability was increased in the patients with minimal HE compared with their neuropsychiatrically unimpaired counterparts (sample entropy: 0.98 [0.87-1.14] vs. 0.83 [0.75-0.95]; p=0.02), and compared with the patients with overt HE (sample entropy: 0.98 [0.87-1.14] vs. 0.82 [0.71-1.01]; p=0.01). CONCLUSIONS: Variability of the EEG is associated with both the presence and severity of HE. This novel finding may provide new insights into the pathophysiology of HE and provide a means for monitoring patients over time. LAY SUMMARY: Decreased variability or increased regularity of physiological systems is documented in several disease states. Variability of the electroencephalogram was found to be associated with both the presence and severity of brain dysfunction in patients with chronic liver disease
Axial form factor of the nucleon in the perturbative chiral quark model
We apply the perturbative chiral quark model (PCQM) at one loop to analyze
the axial form factor of the nucleon. This chiral quark model is based on an
effective Lagrangian, where baryons are described by relativistic valence
quarks and a perturbative cloud of Goldstone bosons as dictated by chiral
symmetry. We apply the formalism to obtain analytical expressions for the axial
form factor of the nucleon, which is given in terms of fundamental parameters
of low-energy pion-nucleon physics (weak pion decay constant, strong
pion-nucleon form factor) and of only one model parameter (radius of the
nucleonic three-quark core).Comment: 23 pages, 5 figures, accepted for publication in J. Phys.
piN scattering and electromagnetic corrections in the perturbative chiral quark model
We apply the perturbative chiral quark model to give predictions for the
electromagnetic O(p^2) low-energy couplings of the ChPT effective Lagrangian
that define the electromagnetic mass shifts of nucleons and first-order (e^2)
radiative corrections to the piN scattering amplitude. We estimate the leading
isospin-breaking correction to the strong energy shift of the pi(-)p atom in
the 1s state, which is relevant for the experiment "Pionic Hydrogen" at PSI.Comment: 12 pages, 2 figure
Measuring Dust Production in the Small Magellanic Cloud Core-Collapse Supernova Remnant 1E 0102.2-7219
We present mid-infrared spectral mapping observations of the core-collapse
supernova remnant 1E 0102.2-7219 in the Small Magellanic Cloud using the
InfraRed Spectrograph (IRS) on the Spitzer Space Telescope. The remnant shows
emission from fine structure transitions of neon and oxygen as well as
continuum emission from dust. Comparison of the mid-IR dust emission with
observations at x-ray, radio and optical wavelengths shows that the dust is
associated with the supernova ejecta and is thus newly formed in the remnant.
The spectrum of the newly formed dust is well reproduced by a model that
includes 3x10^-3 solar masses of amorphous carbon dust at 70 K and 2x10^-5
solar masses of Mg2SiO4 (forsterite) at 145 K. Our observations place a lower
limit on the amount of dust in the remnant since we are not sensitive to the
cold dust in the unshocked ejecta. We compare our results to observations of
other core-collapse supernovae and remnants, particularly Cas A where very
similar spectral mapping observations have been carried out. We observe a a
factor of ~10 less dust in E 0102 than seen in Cas A, although the amounts of
amorphous carbon and forsterite are comparable.Comment: submitted to Ap
- …