139 research outputs found
Statistics of non-linear stochastic dynamical systems under L\'evy noises by a convolution quadrature approach
This paper describes a novel numerical approach to find the statistics of the
non-stationary response of scalar non-linear systems excited by L\'evy white
noises. The proposed numerical procedure relies on the introduction of an
integral transform of Wiener-Hopf type into the equation governing the
characteristic function. Once this equation is rewritten as partial
integro-differential equation, it is then solved by applying the method of
convolution quadrature originally proposed by Lubich, here extended to deal
with this particular integral transform. The proposed approach is relevant for
two reasons: 1) Statistics of systems with several different drift terms can be
handled in an efficient way, independently from the kind of white noise; 2) The
particular form of Wiener-Hopf integral transform and its numerical evaluation,
both introduced in this study, are generalizations of fractional
integro-differential operators of potential type and Gr\"unwald-Letnikov
fractional derivatives, respectively.Comment: 20 pages, 5 figure
Efficient NiII2LnIII2 electrocyclization catalysts for the synthesis of trans-4,5-diaminocyclopent-2-enones from 2-furaldehyde and primary or secondary amines
A series of heterometallic coordination clusters (CCs) [NiII2LnIII2(L1)4Cl2(CH3CN)2] 2CH3CN [Ln = Y (1Y), Sm (1Sm), Eu (1Eu), Gd (1Gd), or Tb (1Tb)] were synthesized by the reaction of (E)-2-(2-hydroxy-3-methoxybenzylidene-amino)phenol) (H2L1) with NiCl2·6(H2O) and LnCl3·x(H2O) in the presence of Et3N at room temperature. These air-stable CCs can be obtained in very high yields from commercially available materials and are efficient catalysts for the room-temperature domino ring-opening electrocyclization synthesis of trans-4,5-diaminocyclopent-2-enones from 2-furaldehyde and primary or secondary amines under a non-inert atmosphere. Structural modification of the catalyst to achieve immobilization or photosensitivity is possible without deterioration in catalytic activity
Health Care Consumers: Choices and Constraints
This article summarizes the research and data currently available on different dimensions of consumer choice. These dimensions include not only whether to participate in a health care plan and which plan to select if given a choice but also the decisions that lead to having a choice and the implications of making the choice. Data are presented on what choices consumers face, how many are given what kinds of choices, what constraints they face, what we know about how they make these choices, and what information they are given and what they use. The majority of Americans are offered some kind of health insurance plan either through their place of employment or as a dependent on someone else’s employer-sponsored health plan. About half of those offered health insurance are offered a choice, usually of only two or three plans. The majority elect to participate in one of those plans.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68465/2/10.1177_107755879905600102.pd
Unique Phase Transition on Spin-2 Triangular Lattice of Ag2MnO2
Ag2MnO2 is studied as a possible candidate compound for an antiferromagnetic
XY spin model on a triangular lattice. In spite of the large Curie-Weiss
temperature of -430 K found in magnetic susceptibi-lity, Mn3+ spins with S = 2
do not undergo a conventional long-range order down to 2 K probably owing to
the geometrical frustration and two dimensionality in the system. Instead, a
unique phase transition is found at 80 K, where specific heat exhibits a clear
sign of a second-order phase transition, while magnetic susceptibility changes
smoothly without a distinct anomaly. We think that this transition is related
to the chirality degree of freedom associated with a short-range order, which
has been expected for the classical XY spin model on a triangular lattice. On
further cooling, spin-glass-like behavior is observed below 22 K, possibly
corresponding to a quasi-long-range order.Comment: to appear in J. Phys. Soc. Jpn, Vol. 77, No.
Zea mays iRS1563: A Comprehensive Genome-Scale Metabolic Reconstruction of Maize Metabolism
The scope and breadth of genome-scale metabolic reconstructions have continued to expand over the last decade. Herein, we introduce a genome-scale model for a plant with direct applications to food and bioenergy production (i.e., maize). Maize annotation is still underway, which introduces significant challenges in the association of metabolic functions to genes. The developed model is designed to meet rigorous standards on gene-protein-reaction (GPR) associations, elementally and charged balanced reactions and a biomass reaction abstracting the relative contribution of all biomass constituents. The metabolic network contains 1,563 genes and 1,825 metabolites involved in 1,985 reactions from primary and secondary maize metabolism. For approximately 42% of the reactions direct literature evidence for the participation of the reaction in maize was found. As many as 445 reactions and 369 metabolites are unique to the maize model compared to the AraGEM model for A. thaliana. 674 metabolites and 893 reactions are present in Zea mays iRS1563 that are not accounted for in maize C4GEM. All reactions are elementally and charged balanced and localized into six different compartments (i.e., cytoplasm, mitochondrion, plastid, peroxisome, vacuole and extracellular). GPR associations are also established based on the functional annotation information and homology prediction accounting for monofunctional, multifunctional and multimeric proteins, isozymes and protein complexes. We describe results from performing flux balance analysis under different physiological conditions, (i.e., photosynthesis, photorespiration and respiration) of a C4 plant and also explore model predictions against experimental observations for two naturally occurring mutants (i.e., bm1 and bm3). The developed model corresponds to the largest and more complete to-date effort at cataloguing metabolism for a plant species
'Do I Really Need to Go to Rehab? I'd Say No, No, No.' Estimating Price Elasticities of Convalescent Care Programs
Withaferin A Alters Intermediate Filament Organization, Cell Shape and Behavior
Withaferin A (WFA) is a steroidal lactone present in Withania somnifera which has been shown in vitro to bind to the intermediate filament protein, vimentin. Based upon its affinity for vimentin, it has been proposed that WFA can be used as an anti-tumor agent to target metastatic cells which up-regulate vimentin expression. We show that WFA treatment of human fibroblasts rapidly reorganizes vimentin intermediate filaments (VIF) into a perinuclear aggregate. This reorganization is dose dependent and is accompanied by a change in cell shape, decreased motility and an increase in vimentin phosphorylation at serine-38. Furthermore, vimentin lacking cysteine-328, the proposed WFA binding site, remains sensitive to WFA demonstrating that this site is not required for its cellular effects. Using analytical ultracentrifugation, viscometry, electron microscopy and sedimentation assays we show that WFA has no effect on VIF assembly in vitro. Furthermore, WFA is not specific for vimentin as it disrupts the cellular organization and induces perinuclear aggregates of several other IF networks comprised of peripherin, neurofilament-triplet protein, and keratin. In cells co-expressing keratin IF and VIF, the former are significantly less sensitive to WFA with respect to inducing perinuclear aggregates. The organization of microtubules and actin/microfilaments is also affected by WFA. Microtubules become wavier and sparser and the number of stress fibers appears to increase. Following 24 hrs of exposure to doses of WFA that alter VIF organization and motility, cells undergo apoptosis. Lower doses of the drug do not kill cells but cause them to senesce. In light of our findings that WFA affects multiple IF systems, which are expressed in many tissues of the body, caution is warranted in its use as an anti-cancer agent, since it may have debilitating organism-wide effects
Relations between Financing and Output in the Not-for-Profit Hospital
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68639/2/10.1177_107755878804500204.pd
Parameter estimations of dynamic systems by means of the principle of minimal excitation energy
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