163 research outputs found
Rotation of an atomic Bose-Einstein condensate with and without a quantized vortex
We theoretically examine the rotation of an atomic Bose-Einstein condensate
in an elliptical trap, both in the absence and presence of a quantized vortex.
Two methods of introducing the rotating potential are considered -
adiabatically increasing the rotation frequency at fixed ellipticity, and
adiabatically increasing the trap ellipticity at fixed rotation frequency.
Extensive simulations of the Gross-Pitaevskii equation are employed to map out
the points where the condensate becomes unstable and ultimately forms a vortex
lattice. We highlight the key features of having a quantized vortex in the
initial condensate. In particular, we find that the presence of the vortex
causes the instabilities to shift to lower or higher rotation frequencies,
depending on the direction of the vortex relative to the trap rotation.Comment: 15 pages, 8 figure
Dynamics of two-component Bose-Einstein condensates in rotating traps
The dynamics of two-component Bose-Einstein condensates in rotating traps is
investigated. In the Thomas-Fermi limit, equations of motion are derived
showing multiple static solutions for a vortex free condensate. Dynamic
stability analysis of these solutions and comparison with Truncated Wigner
simulations enables us to identify the regimes for which vortex states will
occur. In addition, our analysis predicts centre-of-mass oscillations that are
induced by interspecies interactions and affect each component separately. For
attractive interspecies interactions, these oscillations lead to a stable
symmetry broken state.Comment: v4: more material added. 9 pages, 6 figures v5: figures fixed v6:some
rewording v7:fixed figure
Dynamics of two-component Bose-Einstein condensates in rotating traps
The dynamics of two-component Bose-Einstein condensates in rotating traps is
investigated. In the Thomas-Fermi limit, equations of motion are derived
showing multiple static solutions for a vortex free condensate. Dynamic
stability analysis of these solutions and comparison with Truncated Wigner
simulations enables us to identify the regimes for which vortex states will
occur. In addition, our analysis predicts centre-of-mass oscillations that are
induced by interspecies interactions and affect each component separately. For
attractive interspecies interactions, these oscillations lead to a stable
symmetry broken state.Comment: v4: more material added. 9 pages, 6 figures v5: figures fixed v6:some
rewording v7:fixed figure
Hipersuperficies de tipo esférico degenerado
In this work, we dene the hypersurfaces of the spherical type degenerated (in short DST-hypersurfaces), these hypersurfaces has the geometric property that the middle spheres pass through the origin of the Euclidean space. We present a representation for these hypersurfaces in the case where the stereographic projection of the Gauss map N is given by the identity application. We characterizethe DST-hypersurfaces through a diferential equation and we give an explicit example of a two-parameter family of DST-hypersurfaces with planar lines of curvature foliated by (n-1)-dimensional spheres. Moreover, we classify the DST-hypersurfaces of rotation.En este artículo, definimos las hipersuperficies de tipo esférico degenerado (en abreviatura DST-hipersuperficies), estas hipersuperficies tienen la propiedad geométrica de que las esferas medias pasan por el origen del espacio Euclidiano. Presentamos una representación para estas hipersuperficies para el caso en que la proyección estereográfica de la aplicación de Gauss N es dada por la aplicación identidad. Caracterizamos las DST-hipersuperficies a través de una ecuación diferencial y damos un ejemplo explícito de una familia a dos parámetros de DST-hipersuperficies con líneas de curvatura planas foliadas por esferas de dimensión (n-1). Además, clasificamos las DST-hipersuperficies de rotación.
Environmental surveillance identifies multiple introductions of MRSA CC398 in an Equine Veterinary Hospital in the UK, 2011-2016
Bacterial environmental and surgical site infection (SSI) surveillance was implemented from 2011-2016 in a UK Equine Referral Veterinary Hospital and identified 81 methicillin-resistant Staphylococcus aureus (MRSA) isolates. A cluster of MRSA SSIs occurred in early 2016 with the isolates confirmed as ST398 by multilocus sequence typing (MLST), which prompted retrospective analysis of all MRSA isolates obtained from the environment (n = 62), SSIs (n = 13) and hand plates (n = 6) in the past five years. Sixty five of these isolates were typed to CC398 and a selection of these (n = 38) were further characterised for resistance and virulence genes, SCCmec and spa typing. Overall, MRSA was identified in 62/540 (11.5%) of environmental samples, 6/81 of the hand-plates (7.4%) and 13/208 of the SSIs (6.3%). spa t011 was the most frequent (24/38) and Based Upon Repeat Pattern (BURP) analysis identified spa t011 as one of the two group founders of the main spa CC identified across the five years (spa CC011/3423). However, 3 singletons (t073, t786, t064) were also identified suggesting separate introductions into the hospital environment. This long-term MRSA surveillance study revealed multiple introductions of MRSA CC398 in a UK Equine Hospital, identifying an emerging zoonotic pathogen so far only sporadically recorded in the UK
Raman Spectra of Double-Wall Carbon Nanotubes under Extreme Uniaxial Stress
We investigated the pressure dependence of the Raman frequencies and intensities of the D and G bands of double-wall carbon nanotubes under strong uniaxial conditions. Using moissanite anvils, we observed for the first time the evolution of the D band under extreme stress/pressure conditions. We find that the difference between D and G frequencies remains constant over the whole stress range. In addition, we observe that double-wall carbon nanotubes behave elastically up to the maximum uniaxial stress reached in our experiments, which is estimated to be about 12 GPa
Morphological changes in carbon nanohorns under stress: a combined Raman spectroscopy and TEM study
In this work, we present the first study of highly compressed carbon nanohorns (CNHs).</p
Integrated sensor-augmented pump therapy systems [the MiniMed® Paradigm™ Veo system and the Vibe™ and G4® PLATINUM CGM (continuous glucose monitoring) system] for managing blood glucose levels in type 1 diabetes: A systematic review and economic evaluation
Background: In recent years, meters for continuous monitoring of interstitial fluid glucose have been introduced to help people with type 1 diabetes mellitus (T1DM) to achieve better control of their disease. Objective: The objective of this project was to summarise the evidence on the clinical effectiveness and cost-effectiveness of the MiniMed® Paradigm™ Veo system (Medtronic Inc., Northridge, CA, USA) and the Vibe™ (Animas® Corporation, West Chester, PA, USA) and G4® PLATINUM CGM (continuous glucose monitoring) system (Dexcom Inc., San Diego, CA, USA) in comparison with multiple daily insulin injections (MDIs) or continuous subcutaneous insulin infusion (CSII), both with either self-monitoring of blood glucose (SMBG) or CGM, for the management of T1DM in adults and children. Data sources: A systematic review was conducted in accordance with the principles of the Centre for Reviews and Dissemination guidance and the National Institute for He
Evaluating the Effectiveness and Cost-Effectiveness of Seizure Dogs in Persons With Medically Refractory Epilepsy in the Netherlands
__Background:__ Epilepsy is associated with a high disease burden, impacting the lives of
people with epilepsy and their caregivers and family. Persons with medically refractory
epilepsy experience the greatest burden, suffering from profound physical, psychological,
and social consequences. Anecdotal evidence suggests these persons may benefit
from a seizure dog. As the training of a seizure dog is a substantial investment,
their accessibility is limited in the absence of collective reimbursement as is seen
in the Netherlands. Despite sustained interest in seizure dogs, scientific knowledge
on their benefits and costs remains scarce. To substantiate reimbursement decisions
stronger evidence is required. The EPISODE study aims to provide this evidence
by evaluating the effectiveness and cost-effectiveness of seizure dogs in adults with
medically refractory epilepsy.
__Methods:__ The study is designed as a stepped wedge randomized controlled trial that
compares the use of seizure dogs in addition to usual care, with usual care alone. The
study includes adults with epilepsy for whom current treatment options failed to achieve
seizure freedom. Seizure frequency of participants should be at least two seizures per
week, and the seizures should be associated with a high risk of injury or dysfunction.
During the 3 year follow-up period, participants receive a seizure dog in a randomized
order. Outcome measures are taken at multiple time points both before and after receiving
the seizure dog. Seizure frequency is the primary outcome of the study and will be
recorded continuously using a seizure diary. Questionnaires measuring seizure severity,
quality of life, well-being, resource use, productivity, social participation, and caregiver
burden will be completed at baseline and every 3 months thereafter. The study is
designed to include a minimum of 25 participants.
__Discussion:__ This protocol describes the first randomized controlled trial on seizure
dogs. The study will provide comprehensive data on the effectiveness and cost effectiveness
of seizure dogs in adults with medically refractory epilepsy. Broader benefits
of seizure dogs for persons with epilepsy and their caregivers are taken into account,
as well as the welfare of the dogs. The findings of the study can be used to inform
decision-makers on the reimbursement of seizure dogs
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