12,153 research outputs found
Pitch and yaw motions of a human being in free fall
Human limb motions for body orientation during free fal
Alteration of the state of motion of a human being in free fall
Orientation and attitude alteration of human body motion state in free fall studied with mathematical model
Interface Between Topological and Superconducting Qubits
We propose and analyze an interface between a topological qubit and a
superconducting flux qubit. In our scheme, the interaction between Majorana
fermions in a topological insulator is coherently controlled by a
superconducting phase that depends on the quantum state of the flux qubit. A
controlled phase gate, achieved by pulsing this interaction on and off, can
transfer quantum information between the topological qubit and the
superconducting qubit.Comment: 12 pages, 7 figures. V2: Final version as published in Phys. Rev.
Lett, with detailed clarifications in the Appendi
Electromagnetic field induced suppression of transport through - junctions in graphene
We study quasi-particle transmission through an - junction in a
graphene irradiated by an electromagnetic field (EF). In the absence of EF the
electronic spectrum of undoped graphene is gapless, and one may expect the
perfect transmission of quasi-particles flowing perpendicular to the junction.
We demonstrate that the resonant interaction of propagating quasi-particles
with the component of EF parallel to the junction induces a
\textit{non-equilibrium dynamic gap} between electron and hole
bands in the quasi-particle spectrum of graphene. In this case the strongly
suppressed quasi-particle transmission is only possible due to interband
tunnelling. The effect may be used for controlling transport properties of
diverse structures in graphene, like, e.g., -- transistors, single
electron transistors, quantum dots, etc., by variation of the intensity and
frequency of the external radiation.Comment: 5 pages, 3 figure
Understanding and improving the diagnosis of dementia with Lewy bodies
PhD ThesisBackground
Accurate diagnosis of dementia with Lewy bodies (DLB) has important implications for
treatment and prognosis, but it is not currently clear how frequently DLB is diagnosed in
routine clinical practice, nor how frequently they are assigned an alternative dementia
diagnosis.
123I-metaiodobenzylguanidine (MIBG) may be capable of improving DLB diagnostic accuracy
but it has not been investigated in clinically representative populations that include patients
with comorbidities or interfering medications.
Methods
We conducted a cross-sectional survey of 5 569 patients attending three Psychiatry of Old
Age services. From this cohort, 51 DLB and 51 matched non-DLB cases consented to
extraction of data relating to the diagnostic process from their clinical case notes.
We enrolled a clinically representative cohort of 17 patients with DLB and 16 with
Alzheimer’s disease (AD) to a MIBG utility study. Each patient underwent detailed clinical
examination, cardiac MIBG and FP-CIT SPECT imaging.
Results
DLB represented 5.6% of dementia cases but prevalence varied across services (3.5-5.9%).
DLB cases were often given a different dementia subtype diagnosis (39%) and experienced a
longer time from referral to diagnosis (265 days) than non-DLB patients (154 days).
MIBG had a sensitivity and specificity of 71% and 75% for differentiating DLB from AD, but a
lower HMR threshold enhanced specificity (100%) without compromising sensitivity. No
significant relationships between HMR and either myocardial infarction, or medication
prescription, were identified.
ii
Conclusions
Variation in DLB prevalence across services may suggest differences in detection rather than
in the true prevalence of the disease. The higher frequency of clinical contacts seen in DLB
may provide opportunities to improve both diagnostic accuracy and time to diagnosis.
Our findings support the use of representative cohorts in further MIBG research, particularly
in determining appropriate HMR cut-offs. Our finding that three DLB patients had normal
MIBG, but abnormal FP-CIT results challenges the Braak hypothesis of DLB pathogenesi
Predicting Revision Following In Situ Ulnar Nerve Decompression for Patients With Idiopathic Cubital Tunnel Syndrome.
PURPOSE: To determine the incidence of revision and potential risk factors for needing revision surgery following in situ ulnar nerve decompression for patients with idiopathic cubital tunnel syndrome (CTS).
METHODS: We conducted a retrospective chart review of all patients treated at 1 specialty hand center with an open in situ ulnar nerve decompression for idiopathic CTS from January 2006 through December 2010. Revision incidence was determined by identifying patients who underwent additional surgeries for recurrent or persistent ulnar nerve symptoms. Bivariate analysis was performed to determine which variables had a significant influence on the need for revision surgery.
RESULTS: Revision surgery was required in 3.2% (7 of 216) of all cases. Age younger than 50 years at the time of index decompression was the lone significant predictor of need for revision surgery. Other patient factors, including gender, diabetes, smoking history, and workers\u27 compensation status were not predictive of the need for revision surgery. Disease-specific variables including nerve conduction velocities, McGowan grading, and predominant symptom type were also not predictive of revision.
CONCLUSIONS: For patients with idiopathic CTS, the risk of revision surgery following in situ ulnar nerve decompression is low. However, this risk was increased in patients who were younger than 50 years at the time of the index procedure. The findings of this study suggest that, in the absence of underlying elbow arthritis or prior elbow trauma, in situ ulnar nerve decompression is an effective, minimal-risk option for the initial surgical treatment of CTS.
TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic III
Evaluation and Management of Sleep Disorders in the Hand Surgery Patient.
Despite posing a significant public health threat, sleep disorders remain poorly understood and often underdiagnosed and mismanaged. Although sleep disorders are seemingly unrelated, hand surgeons should be mindful of these because numerous conditions of the upper extremity have known associations with sleep disturbances that can adversely affect patient function and satisfaction. In addition, patients with sleep disorders are at significantly higher risk for severe, even life-threatening medical comorbidities, further amplifying the role of hand surgeons in the recognition of this condition
Analysis of heavy spin--3/2 baryon--heavy spin--1/2 baryon--light vector meson vertices in QCD
The heavy spin--3/2 baryon--heavy spin--1/2 baryon vertices with light vector
mesons are studied within the light cone QCD sum rules method. These vertices
are parametrized in terms of three coupling constants. These couplings are
calculated for all possible transitions. It is shown that correlation functions
for these transitions are described by only one invariant function for every
Lorenz structure. The obtained relations between the correlation functions of
the different transitions are structure independent while explicit expressions
of invariant functions depend on the Lorenz structure.Comment: 17 Pages, 6 Figures and 4 Table
High-Field Electrical Transport in Single-Wall Carbon Nanotubes
Using low-resistance electrical contacts, we have measured the intrinsic
high-field transport properties of metallic single-wall carbon nanotubes.
Individual nanotubes appear to be able to carry currents with a density
exceeding 10^9 A/cm^2. As the bias voltage is increased, the conductance drops
dramatically due to scattering of electrons. We show that the current-voltage
characteristics can be explained by considering optical or zone-boundary phonon
emission as the dominant scattering mechanism at high field.Comment: 4 pages, 3 eps figure
Geographic and Age-Based Variations in Medicare Reimbursement Among ASSH Members.
Background: The purpose of this study was to investigate how American Society for Surgery of the Hand (ASSH) members\u27 Medicare reimbursement depends on their geographical location and number of years in practice. Methods: Demographic data for surgeons who were active members of the ASSH in 2012 were obtained using information publicly available through the US Centers for Medicare and Medicaid Services (CMS). Hand-surgeons-per-capita and average reimbursement per surgeon were calculated for each state. Regression analysis was performed to determine a relationship between (1) each state\u27s average reimbursement versus the number of ASSH members in that state, (2) average reimbursement versus number of hand surgeons per capita, and (3) total reimbursement from Medicare versus number of years in practice. Analysis of variance (ANOVA) was used to detect a difference in reimbursement based on categorical range of years as an ASSH member. Results: A total of 1667 ASSH members satisfied inclusion in this study. Although there was significant variation among states\u27 average reimbursement, reimbursement was not significantly correlated with the state\u27s hand surgeons per capita or total number of hand surgeons in that given state. Correlation between years as an ASSH member and average reimbursement was significant but non-linear; the highest reimbursements were seen in surgeons who had been ASSH members from 8 to 20 years. Conclusions: Peak reimbursement from Medicare for ASSH members appears to be related to the time of surgeons\u27 peak operative volume, rather than any age-based bias for or against treating Medicare beneficiaries. In addition, though geographic variation in reimbursement does exist, this does not appear to correlate with density or availability of hand surgeons
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