1,308 research outputs found
A fast branch-and-prune algorithm for the position analysis of spherical mechanisms
The final publication is available at link.springer.comDifferent branch-and-prune schemes can be found in the literature for numerically solving the position analysis of spherical mechanisms. For the prune operation, they all rely on the propagation of motion intervals. They differ in the way the problem is algebraically formulated. This paper exploits the fact that spherical kinematic loop equations can be formulated as sets of 3 multi-affine polynomials. Multi-affinity has an important impact on how the propagation of motion intervals can be performed because a multi-affine polynomial is uniquely determined by its values at the vertices of a closed hyperbox defined in its domain.Peer ReviewedPostprint (author's final draft
Magnetic-Field Induced First-Order Transition in the Frustrated XY Model on a Stacked Triangular Lattice
The results of extensive Monte Carlo simulations of magnetic-field induced
transitions in the xy model on a stacked triangular lattice with
antiferromagnetic intraplane and ferromagnetic interplane interactions are
discussed. A low-field transition from the paramagnetic to a 3-state (Potts)
phase is found to be very weakly first order with behavior suggesting
tricriticality at zero field. In addition to clarifying some long-standing
ambiguity concerning the nature of this Potts-like transition, the present work
also serves to further our understanding of the critical behavior at ,
about which there has been much controversy.Comment: 10 pages (RevTex 3.0), 4 figures available upon request, CRPS-93-0
Synthesizing long-term sea level rise projections – the MAGICC sea level model v2.0
Sea level rise (SLR) is one of the major impacts of global warming; it will threaten coastal populations, infrastructure, and ecosystems around the globe in coming centuries. Well-constrained sea level projections are needed to estimate future losses from SLR and benefits of climate protection and adaptation. Process-based models that are designed to resolve the underlying physics of individual sea level drivers form the basis for state-of-the-art sea level projections. However, associated computational costs allow for only a small number of simulations based on selected scenarios that often vary for different sea level components. This approach does not sufficiently support sea level impact science and climate policy analysis, which require a sea level projection methodology that is flexible with regard to the climate scenario yet comprehensive and bound by the physical constraints provided by process-based models. To fill this gap, we present a sea level model that emulates global-mean long-term process-based model projections for all major sea level components. Thermal expansion estimates are calculated with the hemispheric upwelling-diffusion ocean component of the simple carbon-cycle climate model MAGICC, which has been updated and calibrated against CMIP5 ocean temperature profiles and thermal expansion data. Global glacier contributions are estimated based on a parameterization constrained by transient and equilibrium process-based projections. Sea level contribution estimates for Greenland and Antarctic ice sheets are derived from surface mass balance and solid ice discharge parameterizations reproducing current output from ice-sheet models. The land water storage component replicates recent hydrological modeling results. For 2100, we project 0.35 to 0.56m (66% range) total SLR based on the RCP2.6 scenario, 0.45 to 0.67m for RCP4.5, 0.46 to 0.71m for RCP6.0, and 0.65 to 0.97m for RCP8.5. These projections lie within the range of the latest IPCC SLR estimates. SLR projections for 2300 yield median responses of 1.02m for RCP2.6, 1.76m for RCP4.5, 2.38m for RCP6.0, and 4.73m for RCP8.5. The MAGICC sea level model provides a flexible and efficient platform for the analysis of major scenario, model, and climate uncertainties underlying long-term SLR projections. It can be used as a tool to directly investigate the SLR implications of different mitigation pathways and may also serve as input for regional SLR assessments via component-wise sea level pattern scaling
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Synthesizing long-term sea level rise projections – the MAGICC sea level model v2.0
Sea level rise (SLR) is one of the major impacts of global warming; it will threaten coastal populations, infrastructure, and ecosystems around the globe in coming centuries. Well-constrained sea level projections are needed to estimate future losses from SLR and benefits of climate protection and adaptation. Process-based models that are designed to resolve the underlying physics of individual sea level drivers form the basis for state-of-the-art sea level projections. However, associated computational costs allow for only a small number of simulations based on selected scenarios that often vary for different sea level components. This approach does not sufficiently support sea level impact science and climate policy analysis, which require a sea level projection methodology that is flexible with regard to the climate scenario yet comprehensive and bound by the physical constraints provided by process-based models. To fill this gap, we present a sea level model that emulates global-mean long-term process-based model projections for all major sea level components. Thermal expansion estimates are calculated with the hemispheric upwelling-diffusion ocean component of the simple carbon-cycle climate model MAGICC, which has been updated and calibrated against CMIP5 ocean temperature profiles and thermal expansion data. Global glacier contributions are estimated based on a parameterization constrained by transient and equilibrium process-based projections. Sea level contribution estimates for Greenland and Antarctic ice sheets are derived from surface mass balance and solid ice discharge parameterizations reproducing current output from ice-sheet models. The land water storage component replicates recent hydrological modeling results. For 2100, we project 0.35 to 0.56m (66% range) total SLR based on the RCP2.6 scenario, 0.45 to 0.67m for RCP4.5, 0.46 to 0.71m for RCP6.0, and 0.65 to 0.97m for RCP8.5. These projections lie within the range of the latest IPCC SLR estimates. SLR projections for 2300 yield median responses of 1.02m for RCP2.6, 1.76m for RCP4.5, 2.38m for RCP6.0, and 4.73m for RCP8.5. The MAGICC sea level model provides a flexible and efficient platform for the analysis of major scenario, model, and climate uncertainties underlying long-term SLR projections. It can be used as a tool to directly investigate the SLR implications of different mitigation pathways and may also serve as input for regional SLR assessments via component-wise sea level pattern scaling
Chair and Bed Rise Performance in ADL‐Impaired Congregate Housing Residents
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111141/1/j.1532-5415.2000.tb04999.x.pd
Surgical Outcomes after Full Thickness Chest Wall Resection Followed by Immediate Reconstruction:A 7-Year Observational Study of 42 Cases
Introduction: Reconstruction of full thickness chest wall defects is challenging and is associated with a considerable risk of complications. Therefore, the aim of this study was to investigate the surgical outcomes and their associations with patient and treatment characteristics following full thickness chest wall reconstruction. Patients and methods: A retrospective observational study was performed by including patients who underwent reconstruction of full thickness chest wall defect at the Erasmus MC between January 2014 and December 2020. The type of reconstruction was categorized into skeletal and soft tissue reconstructions. For skeletal reconstruction, only non-rigid prosthetic materials were used. Patient and surgical characteristics were retrieved and analyzed for associations with postoperative complications. Results: Thirty-two women and 10 men with a mean age of 60 years were included. In 26 patients (61.9%), the reconstruction was performed using prosthetic material and a soft tissue flap, in nine cases (21.4%) only a soft tissue flap was used, and in seven other patients (16.7%) only the prosthetic material was used. Pedicled musculocutaneous latissimus dorsi flaps were used most often (n=17), followed by pectoralis major flaps (n=8) and free flaps (n=8). Twenty-two patients (52.4%) developed at least one postoperative complication. Wounds (21.4%) and pulmonary (19.0%) complications occurred most frequently. Five (11.9%) patients required reoperation. There were no associations between patient and treatment characteristics and the occurrence of major complications. There was no mortality. Conclusions: Reconstruction of full thickness chest wall defects using only non-rigid prosthetic material for skeletal reconstruction appears safe with an acceptable reoperation rate and low mortality, questioning the need for rigid fixation techniques.</p
Surgical Outcomes after Full Thickness Chest Wall Resection Followed by Immediate Reconstruction:A 7-Year Observational Study of 42 Cases
Introduction: Reconstruction of full thickness chest wall defects is challenging and is associated with a considerable risk of complications. Therefore, the aim of this study was to investigate the surgical outcomes and their associations with patient and treatment characteristics following full thickness chest wall reconstruction. Patients and methods: A retrospective observational study was performed by including patients who underwent reconstruction of full thickness chest wall defect at the Erasmus MC between January 2014 and December 2020. The type of reconstruction was categorized into skeletal and soft tissue reconstructions. For skeletal reconstruction, only non-rigid prosthetic materials were used. Patient and surgical characteristics were retrieved and analyzed for associations with postoperative complications. Results: Thirty-two women and 10 men with a mean age of 60 years were included. In 26 patients (61.9%), the reconstruction was performed using prosthetic material and a soft tissue flap, in nine cases (21.4%) only a soft tissue flap was used, and in seven other patients (16.7%) only the prosthetic material was used. Pedicled musculocutaneous latissimus dorsi flaps were used most often (n=17), followed by pectoralis major flaps (n=8) and free flaps (n=8). Twenty-two patients (52.4%) developed at least one postoperative complication. Wounds (21.4%) and pulmonary (19.0%) complications occurred most frequently. Five (11.9%) patients required reoperation. There were no associations between patient and treatment characteristics and the occurrence of major complications. There was no mortality. Conclusions: Reconstruction of full thickness chest wall defects using only non-rigid prosthetic material for skeletal reconstruction appears safe with an acceptable reoperation rate and low mortality, questioning the need for rigid fixation techniques.</p
Genome sequence analysis with MonetDB - A case study on Ebola virus diversity
Next-generation sequencing (NGS) technology has led the life sciences into the big data era.
Today, sequencing genomes takes little time and cost, but yields terabytes of data to be stored and analyzed.
Biologists are often exposed to excessively time consuming and error-prone data
management and analysis hurdles.
In this paper, we propose a database management system (DBMS) based
approach to accelerate and substantially simplify genome sequence analysis.
We have extended MonetDB, an open-source
column-based DBMS, with a BAM module, which enables \textit{easy},
\textit{flexible}, and \textit{rapid} management and analysis of sequence
alignment data stored as Sequence Alignment/Map \\(SAM/BAM) files.
We describe the main features of MonetDB/BAM using a case study on Ebola
virus \\genomes
Genome sequence analysis with MonetDB: a case study on Ebola virus diversity
Next-generation sequencing (NGS) technology has led the life sciences into the big data era. Today, sequencing genomes takes little time and cost, but results in terabytes of data to be stored and analysed. Biologists are often exposed to excessively time consuming and error-prone data management and analysis hurdles. In this paper, we propose a database management system (DBMS) based approach to accelerate and substantially simplify genome sequence analysis. We have extended MonetDB, an open-source column-based DBMS, with a BAM module, which enables easy, flexible, and rapid management and analysis of sequence alignment data stored as Sequence Alignment/Map (SAM/BAM) files. We describe the main features of MonetDB/BAM using a case study on Ebola virus genomes
Motion of a driven tracer particle in a one-dimensional symmetric lattice gas
We study the dynamics of a tracer particle subject to a constant driving
force in a one-dimensional lattice gas of hard-core particles whose
transition rates are symmetric. We show that the mean displacement of the
driven tracer grows in time, , as , rather than the linear
time dependence found for driven diffusion in the bath of non-interacting
(ghost) particles. The prefactor is determined implicitly, as the
solution of a transcendental equation, for an arbitrary magnitude of the
driving force and an arbitrary concentration of the lattice gas particles. In
limiting cases the prefactor is obtained explicitly. Analytical predictions are
seen to be in a good agreement with the results of numerical simulations.Comment: 21 pages, LaTeX, 4 Postscript fugures, to be published in Phys. Rev.
E, (01Sep, 1996
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