1,538 research outputs found

    Development of a low actuation voltage RF MEMS switch

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    This paper reports on the design of a novel ultra low actuation voltage, low loss radio frequency micro-electro-mechanical system (RF MEMS) capacitive shunt switch. The concept of the switch relies on a mechanically unconstrained armature actuated over a coplanar waveguide using electrostatic forces. The minimum actuation voltage of the switch is <2V, with an isolation of 40dB and insertion loss <0.7dB at 78GHz

    Adding a subjective dimension to an ICF-based disability measure for people with multiple sclerosis: development and use of a measure for perception of disabilities

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    OBJECTIVE: The subjective dimension of disability, the perception of disability, is a dimension missing from the International Classification of Functioning, Disability and Health (ICF), and from health-related quality of life (HRQOL) instruments. However, it is a highly relevant dimension for clinical practice as perceived disability may identify care needs. We therefore developed a measure for this subjective dimension of disability in multiple sclerosis (MS) and examined the contribution of this dimension to QOL. METHOD: A measure named the Multiple Sclerosis Impact Profile-Disability Perception (MSIP-DP) was developed to reflect a person's perception of disabilities reported using the original MSIP-disability (MSIP-D) items. MS patients (n=530) completed both MSIP sections, the medical outcome study short form questionnaire (SF-36), the World Health Organisation Quality Of Life-BREF (WHOQOL-BREF) and questions concerning disease severity. The contribution of disability perception (DP) to QOL in MS was estimated using hierarchical multiple regression analyses after controlling for MS severity. RESULTS: Confirmative factor analysis confirmed the hypothesised disability perception domains that correspond with the related disability domains in the MSIP. DP scales yielded sufficient reliability. DP explained a unique and substantial part of the variance in QOL, particularly the perception of impairments in mental functions. DISCUSSION: Results indicated that the subjective dimension of functioning and health operationalised in the MSIP-DP is a relevant concept in explaining QOL in MS. In clinical practice psychological interventions addressing a patient's perception of disability, particularly of impairments in mental functioning, may contribute to QOL

    Activated Transport in the individual Layers that form the νT\nu_T=1 Exciton Condensate

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    We observe the total filling factor νT\nu_{T}=1 quantum Hall state in a bilayer two-dimensional electron system with virtually no tunnelling. We find thermally activated transport in the balanced system with a monotonic increase of the activation energy with decreasing d/Bd/\ell_B below 1.65. In the imbalanced system we find activated transport in each of the layers separately, yet the activation energies show a striking asymmetry around the balance point. This implies that the gap to charge-excitations in the {\em individual} layers is substantially different for positive and negative imbalance.Comment: 4 pages. 4 figure

    Chandra Observation of NGC 1559: Eight Ultraluminous X-ray Sources Including a Compact Binary Candidate

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    Despite the 30-year history of ultra-luminous X-ray sources (ULXs) studies, issues like the majority of their physical natures (i.e., neutron stars, stellar-mass black holes, or intermediate black holes) as well as the accretion mechanisms are still under debate. Expanding the ULX sample size in the literature is clearly a way to help. To this end, we investigated the X-ray source population, ULXs in particular, in the barred spiral galaxy NGC 1559 using a Chandra observation made in 2016. In this 45-ks exposure, 33 X-ray point sources were detected within the 2.'7 isophotal radius of the galaxy. Among them, 8 ULXs were identified with the criterion of the X-ray luminosity Lx>1039L_x>10^{39} erg s1^{-1} (0.3-7~keV). Both X-ray light curves and spectra of all the sources were examined. Except for some low-count spectra that only provide ambiguous spectral fitting results, all the X-ray sources were basically spectrally hard and therefore likely have non-thermal origins. While no strong X-ray variability was present in most of the sources owing to the relatively short exposure of the observation, we found an intriguing ULX, named X-24, exhibiting a periodicity of \sim7500s with a detection significance of 2.7σ\sigma. We speculate that it is the orbital period of the system. Roche-lobe over flow and Roche limit are consistent with the speculation. Thus, we suggest that X-24 may be the one of the rare compact binary ULXs, and hence, a good candidate as a stellar-mass black hole.Comment: Accepted for publication in Ap

    Broadening the scope on health problems among the chronically neurologically ill with the International Classification of Functioning (ICF)

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    Purpose. The aim of this study was to determine ICF items indicating health problems for patients with a chronic neurological disorder such as multiple sclerosis, Parkinson's disease and neuromuscular disease. Method. A Delphi study using three disease-specific panels composed of patients and proxies, medical and non-medical health professionals (N=98). Panels were asked to select items from the International Classification of Functioning, Disability and Health (ICF) reflecting relevant disease-specific health problems. Items appraised as relevant by the panel members were compared with items in established measures namely: the Minimal Record of Disability (MRD) and the Disability and Impact Profile (DIP). Results. Sixty-eight ICF items were considered to be the most relevant, and belonged to four ICF domains. No significant differences were found between the appraisal of items by patients/proxies and health professionals. Agreement across the disease panels appeared to be (very) strong. Differences between the three disease-specific panels were found for the 'Body Functions and Structures' domain: consensus was reached by extension of the inclusion criteria. The ICF-item selection covers almost all items of the established measures. The largest contrast was shown in the item selection for the 'participation' and 'environmental factors' domains. Conclusions. Selected items indicate a broader scope in studying health problems compared with widely used health status measures in neurology, especially for the ICF domains 'Participation' and 'Environmental Factors'
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