505 research outputs found
The adaptive computation of far-field patterns by a posteriori error estimations of linear functionals
This paper is concerned with the derivation of a priori and a posteriori error bounds for a class of linear functionals arising in electromagnetics which represent the far-field pattern of the scattered electromagnetic field. The a posteriori error bound is implemented into an adaptive finite element algorithm, and a series of numerical experiments is presented
A simple and optimal ancestry labeling scheme for trees
We present a ancestry labeling scheme for trees. The
problem was first presented by Kannan et al. [STOC 88'] along with a simple solution. Motivated by applications to XML files, the label size was
improved incrementally over the course of more than 20 years by a series of
papers. The last, due to Fraigniaud and Korman [STOC 10'], presented an
asymptotically optimal labeling scheme using
non-trivial tree-decomposition techniques. By providing a framework
generalizing interval based labeling schemes, we obtain a simple, yet
asymptotically optimal solution to the problem. Furthermore, our labeling
scheme is attained by a small modification of the original solution.Comment: 12 pages, 1 figure. To appear at ICALP'1
Ultra-low thermal conductivity in organic-inorganic hybrid perovskite CH3NH3PbI3
We report on the temperature dependence of thermal conductivity of single
crystalline and polycrystalline organometallic perovskite CH3NH3PbI3. The
comparable absolute values and temperature dependence of the two sample's
morphologies indicate the minor role of the grain boundaries on the heat
transport. Theoretical modelling demonstrates the importance of the resonant
scattering in both specimens. The interaction between phonon waves and
rotational degrees of freedom of CH3NH3+ sub-lattice emerges as the dominant
mechanism for attenuation of heat transport and for ultralow thermal
conductivity of 0.5 W/(Km) at room temperature
Peripheral nerve morphology and intraneural blood flow in chronic kidney disease with and without diabetes
Introduction/Aims: Sonographic alterations of peripheral nerves in pre-dialytic kidney disease are yet to be determined. We aimed to assess peripheral nerve cross-sectional area (CSA) and intraneural blood flow in patients with pre-dialytic chronic kidney disease (CKD) and diabetic kidney disease (DKD). Methods: Subjects with CKD (n = 20) or DKD (n = 20) underwent ultrasound to assess CSA of the median and tibial nerves as well as intraneural blood flow of the median nerve. Blood flow was quantified using maximum perfusion intensity. Neuropathy was assessed using the Total Neuropathy Score. A 6-m timed walk test was also performed. Healthy controls (n = 28) were recruited for comparison. Results: The DKD group had more severe neuropathy (p =.024), larger tibial nerve CSA (p =.002) and greater median nerve blood flow than the CKD group (p =.023). Blood flow correlated with serum potassium in disease groups (r = 0.652, p =.022). Disease groups had larger tibial nerve CSA than controls (p <.05). No blood flow was detected in controls. Tibial nerve enlargement was associated with slower maximal walking speeds in disease groups (r = â0.389, p =.021). Discussion: Subjects with DKD demonstrated enlarged tibial nerve CSA and increased median nerve blood flow compared to those with CKD. Elevations in serum potassium were associated with increased blood flow. Sonographic alterations were detectable in pre-dialytic kidney disease compared to controls, highlighting the utility of ultrasound in the assessment of nerve pathology in these patient groups
Functional analyses indicate a pathogenic role of factor H autoantibodies in atypical haemolytic uraemic syndrome
Nondestructive atomic compositional analysis of BeMgZnO quaternary alloys using ion beam analytical techniques
The atomic composition with less than 1-2 atom % uncertainty was measured in
ternary BeZnO and quaternary BeMgZnO alloys using a combination of nondestructive
Rutherford backscattering spectrometry with 1 MeV He
+
analyzing ion beam and non-
Rutherford elastic backscattering experiments with 2.53 MeV energy protons. An
enhancement factor of 60 in the cross-section of Be for protons has been achieved to monitor
Be atomic concentrations. Usually the quantitative analysis of BeZnO and BeMgZnO systems
is challenging due to difficulties with appropriate experimental tools for the detection of the
light Be element with satisfactory accuracy. As it is shown, our applied ion beam technique,
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Accepted Manuscript
supported with the detailed simulation of ion stopping, backscattering, and detection
processes allows of quantitative depth profiling and compositional analysis of wurtzite
BeZnO/ZnO/sapphire and BeMgZnO/ZnO/sapphire layer structures with low uncertainty for
both Be and Mg. In addition, the excitonic bandgaps of the layers were deduced from optical
transmittance measurements. To augment the measured compositions and bandgaps of BeO
and MgO co-alloyed ZnO layers, hybrid density functional bandgap calculations were
performed with varying the Be and Mg contents. The theoretical vs. experimental bandgaps
show linear correlation in the entire bandgap range studied from 3.26 eV to 4.62 eV. The
analytical method employed should help facilitate bandgap engineering for potential
applications, such as solar blind UV photodetectors and heterostructures for UV emitters and
intersubband devices
Mutations in orbit/mast reveal that the central spindle is comprised of two microtubule populations, those that initiate cleavage and those that propagate furrow ingression
We address the relative roles of astral and central spindle microtubules (MTs) in cytokinesis of Drosophila melanogaster primary spermatocytes. Time-lapse imaging studies reveal that the central spindle is comprised of two MT populations, âinteriorâ central spindle MTs found within the spindle envelope and âperipheralâ astral MTs that probe the cytoplasm and initiate cleavage furrows where they contact the cortex and form overlapping bundles. The MT-associated protein Orbit/Mast/CLASP concentrates on interior rather than peripheral central spindle MTs. Interior MTs are preferentially affected in hypomorphic orbit mutants, and consequently the interior central spindle fails to form or is unstable. In contrast, peripheral MTs still probe the cortex and form regions of overlap that recruit the Pav-KLP motor and Aurora B kinase. orbit mutants have disorganized or incomplete anillin and actin rings, and although cleavage furrows initiate, they ultimately regress. Our work identifies a new function for Orbit/Mast/CLASP and identifies a novel MT population involved in cleavage furrow initiation
Mutations in orbit/mast reveal that the central spindle is comprised of two microtubule populations, those that initiate cleavage and those that propagate furrow ingression
We address the relative roles of astral and central spindle microtubules (MTs) in cytokinesis of Drosophila melanogaster primary spermatocytes. Time-lapse imaging studies reveal that the central spindle is comprised of two MT populations, âinteriorâ central spindle MTs found within the spindle envelope and âperipheralâ astral MTs that probe the cytoplasm and initiate cleavage furrows where they contact the cortex and form overlapping bundles. The MT-associated protein Orbit/Mast/CLASP concentrates on interior rather than peripheral central spindle MTs. Interior MTs are preferentially affected in hypomorphic orbit mutants, and consequently the interior central spindle fails to form or is unstable. In contrast, peripheral MTs still probe the cortex and form regions of overlap that recruit the Pav-KLP motor and Aurora B kinase. orbit mutants have disorganized or incomplete anillin and actin rings, and although cleavage furrows initiate, they ultimately regress. Our work identifies a new function for Orbit/Mast/CLASP and identifies a novel MT population involved in cleavage furrow initiation
Four electrons in a two-leg Hubbard ladder: exact ground states
In the case of a two-leg Hubbard ladder we present a procedure which allows
the exact deduction of the ground state for the four particle problem in
arbitrary large lattice system, in a tractable manner, which involves only a
reduced Hilbert space region containing the ground state. In the presented
case, the method leads to nine analytic, linear, and coupled equations
providing the ground state. The procedure which is applicable to few particle
problems and other systems as well is based on an r-space representation of the
wave functions and construction of symmetry adapted orthogonal basis wave
vectors describing the Hilbert space region containing the ground state. Once
the ground state is deduced, a complete quantum mechanical characterization of
the studied state can be given. Since the analytic structure of the ground
state becomes visible during the use of the method, its importance is not
reduced only to the understanding of theoretical aspects connected to exact
descriptions or potential numerical approximation scheme developments, but is
relevant as well for a large number of potential technological application
possibilities placed between nano-devices and quantum calculations, where the
few particle behavior and deep understanding are important key aspects to know.Comment: 19 pages, 5 figure
Direct comparison of steroid and non-steroid eluting small surface pacing leads: Randomized, multicenter clinical trial
BACKGROUND: The aim of the study was to evaluate the effi cacy and safety of small surface steroid-eluting atrial and ventricular pacing leads in comparison to non-steroid leads using remote monitoring system (Biotronik Home Monitoring(R)). METHODS: In this randomized multicenter prospective trial, SIELLO T steroid-eluting ventricular leads (n = 42) were compared to BPPU T non-steroid leads (n = 46) and SIELLO JT steroid-eluting atrial leads (n = 24) to BPPU JT non-steroid leads (n = 27) (Biotronik, Berlin, Germany) in pacemaker devices with remote monitoring capabilities. Lead parameters were evaluated during implantation, at 1-week and 1, 3, 6-month outpatient follow-up. Remote monitoring data were collected weekly. RESULTS: Atrial and ventricular steroid-eluting leads had stable sensing and impedance as compared to non-steroid leads at implantation and during follow-up. Patients with non-steroid atrial leads had signifi cantly higher threshold compared to steroid leads at 1-week and at 1, 3, 6-month follow-up with a peak at 1-month (1-month 1.4 +/- 0.6 vs. 0.7 +/- 0.3 V at 0.4 ms, p < 0.001; 6-month 0.3 +/- 0.5 vs. 0.2 +/- 0.3 V at 0.4 ms, p = 0.002). Patients with non-steroid ventricular leads had signifi cantly higher threshold compared to steroid leads at 1, 3, 6-month (6-month 1.0 +/- 0.3 vs. 0.6 +/- 0.2 V at 0.4 ms, p < 0.001). Remote monitoring confi rmed consistent results. During the study, 3 patients died of non-lead-related death. Lead repositioning was necessary in 2 atrial, 2 ventricular steroid leads and in 1 ventricular non-steroid lead. CONCLUSIONS: Atrial and ventricular pacemaker leads with steroid showed signifi cantly lower pacing threshold compared to non-steroid leads, confi rmed by remote monitoring
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