Applying asynchronous parallel characteristic methods for solving systems of hyperbolic PDEs

We propose asynchronous parallel algorithms for numerically solving systems of hyperbolic partial differential equations. The algorithms are based on the solutions along the characteristic directions. We show that the characteristic directions can be computed in parallel without the need for sharing information or synchronizing on a common time step. This permits the development of efficient asynchronous parallel algorithms. Our solutions cover the cases when the characteristic lines are intersected to form shock waves. We discuss the time performance of our algorithms as well as their implementation on a parallel computer.Supported by the R&D administration of the Ministry of Defense and the Ministry of Immigration Absorption, Israel.     

High Intensity Drying of M.G. Paper

The technological properties of paper are strongly influenced by the drying conditions. This is the case in particular with M.G. paper and machine performance is limited largely for quality reasons. Therefore, the question as to which extent the drying conditions influence the process of drying and the paper quality is of major importance for industry.

Unlike the results already published, tests were carried out with a laboratory machine operating on a continuous basis, with high drying rates, short retention time and application of combined contact/ convectional drying. The kinds of stock used were waste paper containing wood, bleached long-fiber magnefite pulp and unbleached long-fiber sulphate pulp with a basis weight ranging between 37 and 75 g/m2.     

Localization of the labile disulfide bond between SU and TM of the murine leukemia virus envelope protein complex to a highly conserved CWLC motif in SU that resembles the active-site sequence of thiol-disulfide exchange enzymes

Previous studies have indicated that the surface (SU) and transmembrane (TM) subunits of the envelope protein (Env) of murine leukemia viruses (MuLVs) are joined by a labile disulfide bond that can be stabilized by treatment of virions with thiol-specific reagents. In the present study this observation was extended to the Envs of additional classes of MuLV, and the cysteines of SU involved in this linkage were mapped by proteolytic fragmentation analyses to the CWLC sequence present at the beginning of the C-terminal domain of SU. This sequence is highly conserved across a broad range of distantly related retroviruses and resembles the CXXC motif present at the active site of thiol-disulfide exchange enzymes. A model is proposed in which rearrangements of the SU-TM intersubunit disulfide linkage, mediated by the CWLC sequence, play roles in the assembly and function of the Env complex.     

Reduction of interindividual-intergroup discontinuity: The role of leader accountability and proneness to guilt.

Two experiments contrasted interactions between group leaders with interactions between individuals in a mixed-motive setting. Consistent with the idea that being accountable to the in-group implies normative pressure to benefit the in-group, Experiment 1 found that accountable leaders were more competitive than individuals. Consistent with the idea that being unaccountable to the in-group implies normative pressure to be cooperative and that high guilt proneness provides motivation to be moral, Experiment 2 found that when guilt proneness was high, unaccountable leaders were less competitive than accountable leaders and did not differ significantly from individuals. In other words, the robust interindividual-intergroup discontinuity effect was eliminated when groups had unaccountable leaders who were high in guilt proneness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comments on "Silicon models of lateral inhibition" [with reply]

The commenters refer to the above mentioned paper by Wolpert and Micheli-Tzanakou (ibid. p.955-61, 1993), and point out the oversight of previous activity in circuit design. In their opinion the paper in question does not seem to represent a novel approach either in circuitry or computationally. In reply, the authors acknowledge their oversight of the conference papers cited by the commenters, but point out that they never suggested that a simple shunting lateral inhibitory (SLI) pair was a novel circuit, and the overall objective of their effort was simply to carry analysis of SLI to a higher dimension.     

Mathematical modeling of bacteria–virus interactions in Lake Michigan incorporating phosphorus content

Viruses are ubiquitous in aquatic ecosystems and play a critical role in nutrient cycling because viral lysis of cells releases phosphorus, an essential and often limiting nutrient. Previous models have examined dynamics of bacterial and viral communities, but with limited analysis and without explicit consideration of nutrients. A recent model (Fuhrman et al., 2011; Math. Comp. Model. 53, 716-730) incorporated internal nutrient content of bacteria and viruses. In the present study, we modified and tested the model with data from natural planktonic communities from Lake Michigan. Replicate 20 L water samples (135 μm screened), were either untreated or enriched with 8 μM phosphate, and bacterial and viral abundance, chl a fluorescence, and phosphorus (total and dissolved inorganic) were monitored for two weeks. Fuhrman et al.'s model (modified to include phytoplankton) was applied to the data, fitting burst size, lytic latent period and virus decay rate. For enriched samples, model fits were good and parameters were consistent with measurements in other freshwater ecosystems. However, for unenriched samples, where nutrient concentrations approached detection limits, model fits were relatively poorer. The model predicted similar viral decay rates but higher burst sizes and longer latent period in phosphorus-limited versus enriched conditions, underlining the potential importance of nutrients in host–virus interactions. The model is likely to be most useful in meso- to eutrophic systems; requirements for future model development and parameter estimation for application to oligotrophic lakes are discussed.     

Model free kinetics coupled with finite element method for curing simulation of thermosetting epoxy resins

A finite element method algorithm for epoxy curing degree simulation was developed in Abaqus by integrating the discretized analytical solution of the model free kinetics into its user subroutines. This method was verified by nonisothermal and isothermal DSC experiments of an epoxy resin. By means of this method, the real manufacturing press cycle could be simulated regarding temperature distribution and curing degree with advanced curing degree‐dependent material properties. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46408.     

Interaction of polydiallyldimethylammonium salts with iodine

The interaction between polydiallyldimethylammonium chloride (PDADMAC) and KI or KBr, followed by changes in conformation of macromolecules, coil compaction, and counterion exchange, was detected by means of turbidimetry and viscometry. In aqueous solutions at presence of KI, PDADMAC rapidly binds iodine by the formation of polymer–iodine complexes PDADMA I^? I_m (m ≤ 4). Spectrophotometric investigations of the interaction in water without KI prove the formation of complexes of polyquaternary ammonium chloride or bromide with iodine only via iodide. These ions can be generated in the polymer‐catalyzed hydrolysis reaction of iodine. By inducing hydrolysis of iodine and binding the eventually formed iodide, PDADMAC acts as an iodine acceptor with self‐strengthening capacity. For the sorption of gaseous iodine, the possibility of direct interaction of its dipoles with the charged groups of the polyelectrolyte is also reasoned. Polydiallyldimethylammonium halides were used to modify activated carbon and employed in a nuclear power station for treatment of outlet gases containing radioactive iodine. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2710–2716, 2006     

Stability and change of personality across the life course: The impact of age and major life events on mean-level and rank-order stability of the Big Five.

Does personality change across the entire life course, and are those changes due to intrinsic maturation or major life experiences? This longitudinal study investigated changes in the mean levels and rank order of the Big Five personality traits in a heterogeneous sample of 14,718 Germans across all of adulthood. Latent change and latent moderated regression models provided 4 main findings: First, age had a complex curvilinear influence on mean levels of personality. Second, the rank-order stability of Emotional Stability, Extraversion, Openness, and Agreeableness all followed an inverted U-shaped function, reaching a peak between the ages of 40 and 60 and decreasing afterward, whereas Conscientiousness showed a continuously increasing rank-order stability across adulthood. Third, personality predicted the occurrence of several objective major life events (selection effects) and changed in reaction to experiencing these events (socialization effects), suggesting that personality can change due to factors other than intrinsic maturation. Fourth, when events were clustered according to their valence, as is commonly done, effects of the environment on changes in personality were either overlooked or overgeneralized. In sum, our analyses show that personality changes throughout the life span, but with more pronounced changes in young and old ages, and that this change is partly attributable to social demands and experiences. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The hypervariable domain of the murine leukemia virus surface protein tolerates large insertions and deletions, enabling development of a retroviral particle display system

The surface proteins (SU) of murine type-C retroviruses have a central hypervariable domain devoid of cysteine and rich in proline. This 41-amino-acid region of Friend ecotropic murine leukemia virus SU was shown to be highly tolerant of insertions and deletions. Viruses in which either the N-terminal 30 amino acids or the C-terminal 22 amino acids of this region were replaced by the 7-amino-acid sequence ASAVAGA were fully infectious. Insertions of this 7-amino-acid sequence at the N terminus, center, and the C terminus of the hypervariable domain had little effect on envelope protein (Env) function, while this insertion at a position 10 amino acids following the N terminus partially destabilized the association between the SU and transmembrane subunits of Env. Large, complex domains (either a 252-amino-acid single-chain antibody binding domain [scFv] or a 96-amino-acid V1/V2 domain of HIV-1 SU containing eight N-linked glycosylation sites and two disulfides) did not interfere with Env function when inserted in the center or C-terminal portions of the hypervariable domain. The scFv domain inserted into the C-terminal region of the hypervariable domain was shown to mediate binding of antigen to viral particles, demonstrating that it folded into the active conformation and was displayed on the surface of the virion. Both positive and negative enrichment of virions expressing the V1/V2 sequence were achieved by using a monoclonal antibody specific for a conformational epitope presented by the inserted sequence. These results indicated that the hypervariable domain of Friend ecotropic SU does not contain any specific sequence or structure that is essential for Env function and demonstrated that insertions into this domain can be used to extend particle display methodologies to complex protein domains that require expression in eukaryotic cells for glycosylation and proper folding.