196 research outputs found
Realization of XNOR and NAND spin-wave logic gates
We demonstrate the functionality of spin-wave logic XNOR and NAND gates based
on a Mach-Zehnder type interferometer which has arms implemented as sections of
ferrite film spin-wave waveguides. Logical input signals are applied to the
gates by varying either the phase or the amplitude of the spin waves in the
interferometer arms. This phase or amplitude variation is produced by Oersted
fields of dc current pulses through conductors placed on the surface of the
magnetic films.Comment: 5 pages, 2 figure
The First Space-Based Gravitational-Wave Detectors
Gravitational waves provide a laboratory for general relativity and a window
to energetic astrophysical phenomena invisible with electromagnetic radiation.
Several terrestrial detectors are currently under construction, and a
space-based interferometer is envisioned for launch early next century to
detect test-mass motions induced by waves of relatively short wavelength.
Very-long-wavelength gravitational waves can be detected using the plasma in
the early Universe as test masses; the motion induced in the plasma by a wave
is imprinted onto the cosmic microwave background (CMB). While the signature of
gravitational waves on the CMB temperature fluctuations is not unique, the
polarization pattern can be used to unambiguously detect gravitational
radiation. Thus, forthcoming CMB polarization experiments, such as MAP and
Planck, will be the first space-based gravitational-wave detectors.Comment: 5 pages, 3 postscript figure
Mechanical design report of the barrel liquid argon presampler
The note describes the mechanical design of the Atlas barrel presampler and its evolution since the publication of thecalorimeter TDR in December 9
Resonant scattering of spin waves from a region of inhomogeneous magnetic field in a ferromagnetic film
The transmission of a dipole-dominated spin wave in a ferromagnetic film
through a localised inhomogeneity in the form of a magnetic field produced by a
dc current through a wire placed on the film surface was studied experimentally
and theoretically. It was shown that the amplitude and phase of the transmitted
wave can be simultaneously affected by the current induced field, a feature
that will be relevant for logic based on spin wave transport.
The direction of the current creates either a barrier or well for spin wave
transmission. The main observation is that the current dependence of the
amplitude of the spin wave transmitted through the well inhomogeneity is
non-monotonic. The dependence has a minimum and an additional maximum. A theory
was constructed to clarify the nature of the maximum. It shows that the
transmission of spin waves through the inhomogeneity can be considered as a
scattering process and that the additional maximum is a scattering resonance
Systematic review and meta-analysis of the diagnostic accuracy of ultrasonography for deep vein thrombosis
Background
Ultrasound (US) has largely replaced contrast venography as the definitive diagnostic test for deep vein thrombosis (DVT). We aimed to derive a definitive estimate of the diagnostic accuracy of US for clinically suspected DVT and identify study-level factors that might predict accuracy.
Methods
We undertook a systematic review, meta-analysis and meta-regression of diagnostic cohort studies that compared US to contrast venography in patients with suspected DVT. We searched Medline, EMBASE, CINAHL, Web of Science, Cochrane Database of Systematic Reviews, Cochrane Controlled Trials Register, Database of Reviews of Effectiveness, the ACP Journal Club, and citation lists (1966 to April 2004). Random effects meta-analysis was used to derive pooled estimates of sensitivity and specificity. Random effects meta-regression was used to identify study-level covariates that predicted diagnostic performance.
Results
We identified 100 cohorts comparing US to venography in patients with suspected DVT. Overall sensitivity for proximal DVT (95% confidence interval) was 94.2% (93.2 to 95.0), for distal DVT was 63.5% (59.8 to 67.0), and specificity was 93.8% (93.1 to 94.4). Duplex US had pooled sensitivity of 96.5% (95.1 to 97.6) for proximal DVT, 71.2% (64.6 to 77.2) for distal DVT and specificity of 94.0% (92.8 to 95.1). Triplex US had pooled sensitivity of 96.4% (94.4 to 97.1%) for proximal DVT, 75.2% (67.7 to 81.6) for distal DVT and specificity of 94.3% (92.5 to 95.8). Compression US alone had pooled sensitivity of 93.8 % (92.0 to 95.3%) for proximal DVT, 56.8% (49.0 to 66.4) for distal DVT and specificity of 97.8% (97.0 to 98.4). Sensitivity was higher in more recently published studies and in cohorts with higher prevalence of DVT and more proximal DVT, and was lower in cohorts that reported interpretation by a radiologist. Specificity was higher in cohorts that excluded patients with previous DVT. No studies were identified that compared repeat US to venography in all patients. Repeat US appears to have a positive yield of 1.3%, with 89% of these being confirmed by venography.
Conclusion
Combined colour-doppler US techniques have optimal sensitivity, while compression US has optimal specificity for DVT. However, all estimates are subject to substantial unexplained heterogeneity. The role of repeat scanning is very uncertain and based upon limited data
Stigma and Fear: the 'Psy Professional' in Cultural Artifacts
This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.The loss of reason called madness provokes perhaps the greatest human fear, for it is reason that
dignifies humanity and separates us from beasts. The âpsy professionalsâ - those who prescribe and
administer treatments for madness - are frequently portrayed in fiction, film, comics, computer
games and entertainments, along with the mad themselves and the asylums that confine them.
Overall, these depictions are malign: the reader/watcher/player is encouraged to fear the mad, the
madhouse and the mad-doctor. Choosing to use less abrasive vocabulary to name the condition of
madness makes no difference to the terror the condition arouses, for the content of many books and
games aims to inspire fear. In spite of considerable efforts over many years, the stigma which
attaches to mental illness remains firmly in place for patients, while psy professionals also carry their
share of âsome of the discredit of the stigmatizedâ (Goffman 1968, p 43) and join patients in a
stigmatized group. Popular belief often equates the psy professions with madness (Walter, 1989).
This paper explores ways in which the fear of madness, and the stigma which clings to sufferers and
their professional carers, is perpetuated by a constant stream of popular cultural artifacts
High-dimensional interior crisis in the Kuramoto-Sivashinsky equation
An investigation of interior crisis of high dimensions in an extended spatiotemporal system exemplified by the Kuramoto-Sivashinsky equation is reported. It is shown that unstable periodic orbits and their associated invariant manifolds in the Poincaré hyperplane can effectively characterize the global bifurcation dynamics of high-dimensional systems.A. C.-L. Chian, E. L. Rempel, E. E. Macau, R. R. Rosa, and F. Christianse
Chronic fatigue syndrome: identifying zebras amongst the horses
There are currently no investigative tools or physical signs that can confirm or refute the presence of chronic fatigue syndrome (CFS). As a result, clinicians must decide how long to keep looking for alternative explanations for fatigue before settling on a diagnosis of CFS. Too little investigation risks serious or easily treatable causes of fatigue being overlooked, whilst too many increases the risk of iatrogenic harm and reduces the opportunity for early focused treatment. A paper by Jones et al published this month in BMC Medicine may help clinicians in deciding how to undertake such investigations. Their results suggest that if clinicians look for common psychiatric and medical conditions in those complaining of prolonged fatigue, the rate of detection will be higher than previously estimated. The most common co-morbid condition identified was depression, suggesting a simple mental state examination remains the most productive single investigation in any new person presenting with unexplained fatigue. Currently, most diagnostic criteria advice CFS should not be diagnosed when an active medical or psychiatric condition which may explain the fatigue is identified. We discuss a number of recent prospective studies that have provided valuable insights into the aetiology of chronic fatigue and describe a model for understanding chronic fatigue which may be equally relevant regardless of whether or not an apparent medical cause for fatigue can be identified
Suppression of Penning discharges between the KATRIN spectrometers
The KArlsruhe TRItium Neutrino experiment (KATRIN) aims to determine the effective electron (anti)-neutrino mass with a sensitivity of 0.2eV/c by precisely measuring the endpoint region of the tritium ÎČ-decay spectrum. It uses a tandem of electrostatic spectrometers working as magnetic adiabatic collimation combined with an electrostatic (MAC-E) filters. In the space between the pre-spectrometer and the main spectrometer, creating a Penning trap is unavoidable when the superconducting magnet between the two spectrometers, biased at their respective nominal potentials, is energized. The electrons accumulated in this trap can lead to discharges, which create additional background electrons and endanger the spectrometer and detector section downstream. To counteract this problem, âelectron catchersâ were installed in the beamline inside the magnet bore between the two spectrometers. These catchers can be moved across the magnetic-flux tube and intercept on a sub-ms time scale the stored electrons along their magnetron motion paths. In this paper, we report on the design and the successful commissioning of the electron catchers and present results on their efficiency in reducing the experimental background
Symbolic Object Code Analysis
Current software model checkers quickly reach their limit when being applied to verifying pointer safety properties in source code that includes function pointers and inlined assembly. This paper introduces an alternative technique for checking pointer safety violations, called Symbolic Object Code Analysis (SOCA), which is based on bounded symbolic execution, incorporates path-sensitive slicing, and employs the SMT solver Yices as its execution and verification engine. Extensive experimental results of a prototypic SOCA Verifier, using the Verisec suite and almost 10,000 Linux device driver functions as benchmarks, show that SOCA performs competitively to current source-code model checkers and that it also scales well when applied to real operating systems code and pointer safety issues. SOCA effectively explores semantic niches of software that current software verifiers do not reach
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