43 research outputs found
Electron microscopic demonstration of centrifugal nerve fibers in the human optic nerve
Electron microscopic views of centrifugal nerve fibers in the optic nerve stump of a 56-year-old man are presented. These nerve fibers had survived for 16 days after removal of the corresponding eyeball and exhibited terminal swellings pointing in a distal direction and indicating axoplasmic flow towards the removed eye. The centrifugal nerves in this adult lack any evidence of attempted regeneration that has earlier been observed under similar conditions in the optic nerve stump of a child. Zentrifugale (antidrome, efferente) Nervenfasern sind hier zum ersten Mal mit dem Elektronenmikroskop im menschlichen Sehnerven dargestellt worden. Diese Nervenfasern wurden in dem Sehnervenstumpf eines 56jĂ€hrigen Mannes 16 Tage nach der Entfernung des dazugehörigen Auges gefunden. Endschwellungen dieser Nervenfasern waren distal ausgerichtet und deuteten damit einen AxoplasmafluĂ in Richtung des entfernten Auges an. WĂ€hrend deutliche Regenerationsversuche an den distalen Enden unterbrochener zentrifugaler Nervenfasern im Sehnervenstumpf eines Kindes frĂŒher beobachtet worden sind, fanden sich im Sehnerven dieses Erwachsenen keinerlei Zeichen von Regeneration der zentrifugalen Fasern.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47369/1/417_2004_Article_BF00414787.pd
Qualitative behavior of solutions for thermodynamically consistent Stefan problems with surface tension
The qualitative behavior of a thermodynamically consistent two-phase Stefan
problem with surface tension and with or without kinetic undercooling is
studied. It is shown that these problems generate local semiflows in
well-defined state manifolds. If a solution does not exhibit singularities in a
sense made precise below, it is proved that it exists globally in time and its
orbit is relatively compact. In addition, stability and instability of
equilibria is studied. In particular, it is shown that multiple spheres of the
same radius are unstable, reminiscent of the onset of Ostwald ripening.Comment: 56 pages. Expanded introduction, added references. This revised
version is published in Arch. Ration. Mech. Anal. (207) (2013), 611-66
Antileishmanial activity of extracts from Libidibia ferrea: development of in vitro and in vivo tests
Genetics of the induction of antigen-specific immunity in anti-idiotype-treated mice and derivation of monoclonal Ab3 antibodies
Abortive infection of Lutzomyia longipalpis insect vectors by aflagellated LdARL-3A-Q70L overexpressing Leishmania amazonensis parasites
A modelling approach to estimate the sensitivity of pooled faecal samples for isolation of Salmonella in pigs
The objective of this study was to develop and parametrize a mathematical model of the sensitivity of pooled sampling of faeces to detect Salmonella infection in pigs. A mathematical model was developed to represent the effect of pooling on the probability of Salmonella isolation. Parameters for the model were estimated using data obtained by collecting 50 faecal samples from each of two pig farms. Each sample was tested for Salmonella at individual sample weights of 0.1, 0.5, 1, 10 and 25âg and pools of 5, 10 and 20 samples were created from the individual samples. The highest test sensitivity for individual samples was found at 10âg (90% sensitivity), with the 25âg test sensitivity equal to 83%. For samples of less than 10âg, sensitivity was found to reduce with sample weight. Incubation for 48âh was found to produce a more sensitive test than incubation for 24âh. Model results found increasing sensitivity with more samples in the pool, with the pools of 5, 10 and 20 being more sensitive than individual sampling, and the pools of 20 being the most sensitive of those considered
Testing for asymptomatic herpes simplex virus type 2: Implications for pretest and post-test counseling
Accelerated Greenland Ice Sheet Mass Loss Under High Greenhouse Gas Forcing as Simulated by the Coupled CESM2.1-CISM2.1
The Greenland ice sheet (GrIS) is now losing mass at a rate of 0.7 mm of sea level rise (SLR) per year. Here we explore future GrIS evolution and interactions with global and regional climate under high greenhouse gas forcing with the Community Earth System Model version 2.1 (CESM2.1), which includes an interactive ice sheet component (the Community Ice Sheet Model v2.1 [CISM2.1]) and an advanced energy balance-based calculation of surface melt. We run an idealized 350-year scenario in which atmospheric CO2 concentration increases by 1% annually until reaching four times pre-industrial values at year 140, after which it is held fixed. The global mean temperature increases by 5.2 and 8.5 K by years 131â150 and 331â350, respectively. The projected GrIS contribution to global mean SLR is 107 mm by year 150 and 1,140 mm by year 350. The rate of SLR increases from 2 mm yrâ1 at year 150 to almost 7 mm yrâ1 by year 350. The accelerated mass loss is caused by rapidly increasing surface melt as the ablation area expands, with associated albedo feedback and increased sensible and latent heat fluxes. This acceleration occurs for a global warming of approximately 4.2 K with respect to pre-industrial and is in part explained by the quasi-parabolic shape of the ice sheet, which favors rapid expansion of the ablation area as it approaches the interior âplateau.â.</p
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An Efficient Ice Sheet/Earth System Model Spin-up Procedure for CESM2-CISM2: Description, Evaluation, and Broader Applicability
Spinning up a highly complex, coupled Earth system model (ESM) is a time consuming and computationally demanding exercise. For models with interactive ice sheet components, this becomes a major challenge, as ice sheets are sensitive to bidirectional feedback processes and equilibrate over glacial timescales of up to many millennia. This work describes and demonstrates a computationally tractable, iterative procedure for spinning up a contemporary, highly complex ESM that includes an interactive ice sheet component. The procedure alternates between a computationally expensive coupled configuration and a computationally cheaper configuration where the atmospheric component is replaced by a data model. By periodically regenerating atmospheric forcing consistent with the coupled system, the data atmosphere remains adequately constrained to ensure that the broader model state evolves realistically. The applicability of the method is demonstrated by spinning up the preindustrial climate in the Community Earth System Model Version 2 (CESM2), coupled to the Community Ice Sheet Model Version 2 (CISM2) over Greenland. The equilibrium climate state is similar to the control climate from a coupled simulation with a prescribed Greenland ice sheet, indicating that the iterative procedure is consistent with a traditional spin-up approach without interactive ice sheets. These results suggest that the iterative method presented here provides a faster and computationally cheaper method for spinning up a highly complex ESM, with or without interactive ice sheet components. The method described here has been used to develop the climate/ice sheet initial conditions for transient, ice sheet-enabled simulations with CESM2-CISM2 in the Coupled Model Intercomparison Project Phase 6 (CMIP6).Physical and Space Geodes
Comparing and generating Latin Hypercube designs in Kriging models
Computer experiments, Latin hypercube, Mean square prediction error, Gaussian linear prediction,