296 research outputs found
Totally odd depth-graded multiple zeta values and period polynomials
Inspired by a paper of Tasaka, we study the relations between totally odd,
motivic depth-graded multiple zeta values. Our main objective is to determine
the rank of the matrix defined by Brown. We will give new proofs for
(conjecturally optimal) upper bounds on the rank of and ,
which were first obtained by Tasaka. Finally, we present a recursive approach
to the general problem, which reduces evaluating the rank of to an
isomorphism conjecture.Comment: 14 page
GEM-Selektor geochemical modeling package: revised algorithm and GEMS3K numerical kernel for coupled simulation codes
Reactive mass transport (RMT) simulation is a powerful numerical tool to advance our understanding of complex geochemical processes and their feedbacks in relevant subsurface systems. Thermodynamic equilibrium defines the baseline for solubility, chemical kinetics, and RMT in general. Efficient RMT simulations can be based on the operator-splitting approach, where the solver of chemical equilibria is called by the mass transport part for each control volume whose composition, temperature, or pressure has changed. Modeling of complex natural systems requires consideration of multiphase-multicomponent geochemical models that include nonideal solutions (aqueous electrolytes, fluids, gases, solid solutions, and melts). Direct Gibbs energy minimization (GEM) methods have numerous advantages for the realistic geochemical modeling of such fluid-rock systems. Substantial improvements and extensions to the revised GEM interior point method algorithm based on Karpov's convex programming approach are described, as implemented in the GEMS3K C/C+ + code, which is also the numerical kernel of GEM-Selektor v.3 package ( http://gems.web.psi.ch ). GEMS3K is presented in the context of the essential criteria of chemical plausibility, robustness of results, mass balance accuracy, numerical stability, speed, and portability to high-performance computing systems. The stand-alone GEMS3K code can treat very complex chemical systems with many nonideal solution phases accurately. It is fast, delivering chemically plausible and accurate results with the same or better mass balance precision as that of conventional speciation codes. GEMS3K is already used in several coupled RMT codes (e.g., OpenGeoSys-GEMS) capable of high-performance computin
Automated Generation of Shuttling Sequences for a Linear Segmented Ion Trap Quantum Computer
A promising approach for scaling-up trapped-ion quantum computer platforms is
by storing multiple trapped-ion qubit sets ('ion crystals') in segmented
microchip traps and to interconnect these via physical movement of the ions
('shuttling'). Already for realizing quantum circuits with moderate complexity,
the design of suitable qubit assignments and shuttling schedules require
automation. Here, we describe and test algorithms which address exactly these
tasks. We describe an algorithm for fully automated generation of shuttling
schedules, complying to constraints imposed by a given trap structure.
Furthermore, we introduce different methods for initial qubit assignment and
compare these for random circuit (of up to 20 qubits) and quantum Fourier
transform-like circuits, and generalized Toffoli gates of up to 40 qubits each.
We find that for quantum circuits which contain a fixed structure, advanced
assignment algorithms can serve to reduce the shuttling overhead
Clinical examination and patients’ history are not suitable for neonatal hip screening
PURPOSE: To assess the percentage of missed developmental dysplasia of the hip, which escape the German criteria for newborn hip high-risk screening, we analyzed our data gained from the general neonatal sonographic hip screening performed at our department. The aim of the study was to determine the number of potentially belatedly treated developmental dysplasia of the hip. METHODS: The data from 1145 standardized newborn hip ultrasound examinations according to the Graf technique were analyzed retrospectively comparing findings for general neonatal sonographic hip screening and high-risk screening subgroups. RESULTS: We diagnosed developmental dysplasia of the hip in 18 of the 1145 newborns via ultrasound. A total of 10 out of 18 developmental dysplasia of the hip would have been missed by high-risk screening, which corresponds to a proportion of 55.6% false-negative results. The sensitivity of high-risk screening was only 44.4% and specificity, 78.3%. The positive predictive value was 3.2%. Family history as a screening criterion yielded false-negative results in 77.8% and false-positive results in 16.8%. In all, 83.3% of the children who were born with developmental dysplasia of the hip but not from breech position as a risk factor were false negative. The clinical examination was false negative in 88.9% and false positive in 0.6%. CONCLUSION: High-risk screening detected less than every second developmental dysplasia of the hip, rendering the first month as the most effective treatment window unavailable for inapparent dysplastic hips, potentially resulting in the need for more invasive treatment. Due to the high sensitivity of ultrasound in the detection of developmental dysplasia of the hip, we recommend to replace the current German high-risk screening guidelines with a general newborn screening for all neonates using Graf ultrasound in the first week of life. LEVEL OF EVIDENCE: Level II
Quantum Circuit Compiler for a Shuttling-Based Trapped-Ion Quantum Computer
The increasing capabilities of quantum computing hardware and the challenge
of realizing deep quantum circuits require fully automated and efficient tools
for compiling quantum circuits. To express arbitrary circuits in a sequence of
native gates specific to the quantum computer architecture, it is necessary to
make algorithms portable across the landscape of quantum hardware providers. In
this work, we present a compiler capable of transforming and optimizing a
quantum circuit targeting a shuttling-based trapped-ion quantum processor. It
consists of custom algorithms set on top of the quantum circuit framework
Pytket. The performance was evaluated for a wide range of quantum circuits and
the results show that the gate counts can be reduced by factors up to 5.1
compared to standard Pytket and up to 2.2 compared to standard Qiskit
compilation.Comment: 35 pages, 25 figures, 4 tables, accepted in Quantu
Trajectory angles of muscles originating from and inserting to the coxal femoral bone measured on MRIs
Trajectory angles of muscles originating from and inserting to the coxal femoral bone measured on MRIs. Open access supplementary material as appendix to the original article "Muscle forces acting on the greater trochanter lead to a dorsal warping of the apophyseal growth plate" published in Journal of Anatomy
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