North-Holland Publishing Company Research Articles

First-order linear Marcus SPDEs

In this paper, we solve a Lévy driven linear stochastic first-order partial differential equation (transport equation) understood in the canonical (Marcus) form. The solution can be obtained with the help of the method of stochastic characteristics. It has the same form as a solution of a deterministic PDE or a solution of a stochastic PDE driven by a Brownian motion studied by Kunita [First order stochastic partial differential equations, in Stochastic Analysis. Proc. Taniguchi Int. Symp. Stochastic Analysis, Katata and Kyoto, 1982, North-Holland Mathematical Library, Vol. 32, ed. K. Itô (North-Holland Publishing Company, 1984), pp. 249–269; Stochastic Flows and Stochastic Differential Equations, Vol. 24 (Cambridge University Press, 1997)].

Decomposition and discrete approximation methods for solving two-stage distributionally robust optimization problems

Decomposition methods have been well studied for solving two-stage and multi-stage stochastic programming problems, see Rockafellar and Wets (Math. Oper. Res. 16:119–147, 1991), Ruszczynski and Shapiro (Stochastic Programming, Handbook in OR & MS, North-Holland Publishing Company, Amsterdam, 2003) and Ruszczynski (Math. Program. 79:333–353, 1997). In this paper, we propose an algorithmic framework based on the fundamental ideas of the methods for solving two-stage minimax distributionally robust optimization (DRO) problems where the underlying random variables take a finite number of distinct values. This is achieved by introducing nonanticipativity constraints for the first stage decision variables, rearranging the minimax problem through Lagrange decomposition and applying the well-known primal-dual hybrid gradient (PDHG) method to the new minimax problem. The algorithmic framework does not depend on specific structure of the ambiguity set. To extend the algorithm to the case that the underlying random variables are continuously distributed, we propose a discretization scheme and quantify the error arising from the discretization in terms of the optimal value and the optimal solutions when the ambiguity set is constructed through generalized prior moment conditions, the Kantorovich ball and $$\phi$$ -divergence centred at an empirical probability distribution. Some preliminary numerical tests show the proposed decomposition algorithm featured with parallel computing performs well.

Effect of substituted concentration on structure and magnetic properties of Y3Fe5-xInxO12

Abstract: This study examines the effect of substituted concentration on the structure and magnetic properties of Y3Fe5-xInxO12 (x = 0.1 ÷ 0.7) powder samples prepared using the sol-gel method. The morphological properties of the samples were analysed using XRD, SEM. The single phase of garnet was obtained in x = 0.1 ÷ 0.6 samples. The lattice parameters of the samples exhibit a linear increase with the increasing In3+ content, which can be explained by a substitution of In3+ ions for Fe3+ ions, considering the larger ionic radius of In3+ compared with that of Fe3+. Crystallite sizes were determined via the XRD data which are of 38 – 49 nm while the particle sizes were estimated from SEM images to be in range of 50 - 100 nm. Magnetization and Curie temperature of the single phase samples were studied by magnetization curves in fields up to 10 kOe and in the temperature range from 80 K to 560K. With the increase of In3+, the magnetization gradually increases while the Curie temperature decreases due to the occupation of In atoms at the a sites and the reduction of intersublattice interaction, respectively.
 Keywords: Yttrium iron garnet, Indium substitution, cation distribution, magnetization, Curie temperature.
 References[1] R. L. Streever, Anisotropic exchange in ErIG, Journal of Magnetism and Magnetic Materials 278 (1-2) (2014) 223-230.[2] N.I. Tsidaeva, The magnetic and magnetooptical properties of Y-substituted erbium iron garnet single crystals, Journal of Alloys and Compounds 374 (1-2) (2004) 160-164.[3] Y.Nakata, T. Okada, M. Maeda, S. Higuchi and K. Ueda, Effect of oxidation dynamics on the film characteristics of Ce:YIG thin films deposited by pulsed laser deposition, Optics and Lasers in Engineering 44 (2) 2006, 147-154.[4] M. Laulajainen, P. Paturi, J. Raittila, H. Huhtinen, A.B. Abrahamsen, N.H. Andersen and R. Laiho, BixY3-xFe5O12 thin film prepared by laser ablation for magneto-optical imaging of superconducting thin films, Journal of Magnetism and Magnetic Materials 279 (2-3) (2004) 218-223.[5] A.A. Lagutin, G.E. Fedorov, J. Vanacken and D. Herlach, Magnetic properties of dysprosium Yttrium ferrite garnet in pulsed magnetic fields at low temperatures, Journal of Magnetism and Mmagnetic Materials 195 (1999) 97-106.[6] S.A. Nikotov, Nonlinearity: Magneto-optic microwave interactions. Towards new devices, Journal of Magnetism and Magnetic Materials (196-197) (1999) 400-403.[7] C.S. Tsai, Wideband tunable microwave devices using, European Ceramic Society 23 (14) (2003) 2721-2726.[8] A. Sztaniszlav, M. Farkas-Jahnke, M. Balla, Kinetics of garnet formation in In3+ substituted systems, Journal of Magnetism and Magnetic Materials 215-216 (2000) 188-193.[9] R.G. Vidhate, V.D. Murumkas, R.G. Dorik, N.M. Makne, S.R. Nimbore, K.M. Jadhav, Magnetic properties of In Substituted ytrium iron garnet (YIG), Rev. Res. 1(10) (2012) 1-4.[10] G. Cuijing, Z. Wei, J. Rongjin, Z. Yanwei, Effect of In3+ substitution on the structure and magnetic properties of multi-doped YIG ferrites with low saturation magnetizations, Journal of Magnetism and Magnetic Materials 323, (2011) 611-615.[11] Vu Thi Hoai Huong, Dao Thi Thuy Nguyet, To Thanh Loan, Luong Ngoc Anh, Nguyen Phuc Duong, Than Duc Hien, Structural and magnetic properties of Y3-2xCa2xFe5-xVxO12 nanoparticles prepared by sol-gel method, Proceeding of the 3rd International Conference on Advanced Materials and Nanotechnology (2016) 219-223.[12] Imaddin A. Al-Omari, Ralph Skomski, David J. Sellmyer, Magnetic properties of Y3-2xCa2xFe5-xVxO12 garnets, Advances in Materials Physics and Chemistry 2 (2012) 116-120.[13] Rodziah Nazlan, Mansorhashim, Idza Riati Ibrahim, Fadzidah Mohd Idris, Wan Norailiana Wan Ab Rahman, Nor Hapishah Abdullah, Ismayadi Ismail, Saikannu Kanagesan, Zulkifly Abbas, Rabaah Syahidah Azis, Influence of Indium substitution and microstructure changes on the magnetic properties evolution of Y3Fe5-xInxO12 (x = 0.0 – 0.4), Journal of Material Science: Materials in Electronics 26, 6 (2015) 3596-3609.[14] M. Niyaifar, A. Beitollahi, N. Shiri, M. Mozaffari, J. Amighian, Effect of indium addition on the structure and magnetic properties of YIG, Journal of Magnetism and Magnetic Materials 322 (2010) 777 – 779.[15] J. Richard Cunningham Jr and Elmer E. Anderson, Effect of indium substitution in Yttrium iron garnet. High permeability garnets, Journal of Applied Physics 32, (1961) S388.[16] L. Vegard Dr. Phil, LV. Results of crystal analysis. –III, Philosophical magazine Series 6, 32: 191, 505 – 518.[17] Ronald W. Armstrong, Crystal dislocations, Crystals 6, 1 (2016) 9.[18] Gerald F. Dionne, Molecular field coefficients of substituted yttrium iron garnets, Journal of Applied Physics. 41 (1970) 4874.[19] M.A. Gilleo, Ferromagnetic insulators: Garnets, in: E.P. Wohlfarth (Ed.), Handbook of Magnetic Materials, Volume 2, North-Holland Publishing Company, 1980, 1-54.[20] Z. Azadi Motlagh, M. Mozaffari, J. Smighian, Preparation of nano-sized Al-substituted yttrium iron garnets by the mechanochemical method and investigation of their magnetic properties, Journal of Magnetism and Magnetic Materials 321 (2009) 1980-1984.[21] P. Belov and I.S. Lyubutin, Effective magnetic fields at tin nuclei in substituted iron garnets CaxY3-x SnxFe5-x O12, Soviet Physics JETP 22 (3) (1966) 518 – 520.

Identifiability of structural characteristics: How relevant is it for the Bayesian approach?

The role of identification in the Bayesian approach is still debatable. Since Lindley [Bayesian Statistics. A Review (1971) Philadelphia], most Bayesian statisticians pretend that unidentifiabiity causes no real difficulty in their approach. Recently, Wechsler, Izbicki and Esteves [Amer. Statist. 67 (2013) 90–93] provide a simple example illustrating this perspective. By critically reading Wechsler, Izbicki and Esteves [Amer. Statist. 67 (2013) 90–93], we intend to show that the Bayesian approach is far from being free of the identification problems, provided that the interest is focused on the interpretation of the parameters. It is written using a rather ancient style, the so-called Platonic dialogues. In modern times, there are beautiful examples of that, particularly in Foundations of Mathematics, where debatable subjects are discussed: let us refer Heyting [Intuitionism. An Introduction (1971) North-Holland Publishing Company], where the debate between a formalist and an intuitionist is presented as a dialogue; or Lakatos [Proofs and Refutations. The Logic of Mathematical Discovery (1976) Cambridge University Press], where the relationship between proofs and conjectures is magnificently illustrated. We hope that this style will help to understand why identifiability really matters in the Bayesian approach.

Fatigue from defect under multiaxial loading: Defect Stress Gradient (DSG) approach using ellipsoidal Equivalent Inclusion Method

The fatigue design of metallic parts depends on the casting process. It requires a compromise between the fatigue resistance of the component and the allowable defect size due to the process. The research team has proposed, in previous work [Leopold G, Nadot Y. J ASTM Int 7:2010], to represent the effect of a defect in the fatigue criterion by means of a stress gradient term. This general methodology called Defect Stress Gradient (DSG) can consider explicitly the type, the morphology and the size of the defect due to the fact that a Finite Element (FE) submodel describes directly the defect at the mesoscopic scale. The DSG approach gives correct results for the defects range from 100 to 1000μm but it is limited for application to full scale components by the use of FE submodel. The aim of this paper is to present an upgraded version of the DSG approach using the Equivalent Inclusion Method (EIM) due to Eshelby [Eshelby JD. Proc Royal Soc Lond Ser A. Math Phys Sci 241:1957; 376–96], [Eshelby JD. Elastic inclusions and inhomogeneities. In: Sneddon IN, Hill R (Eds.), Progress in solid mechanics 2. Amsterdam: North-Holland Publishing Company; 1961. p. 89–140] to compute stresses around the defect. Using this analytical approach, it is possible to compute the stresses around an ellipsoidal defect without FE simulations. Furthermore, the EIM for an ellipsoidal defect is efficient to address the question of the defect size related to loading direction in the case of a non-spherical defect. Although the framework of the original EIM is for internal defect, this paper shows that its application for a surface defect gives fair results in the context of the DSG approach. The new DSG proposal is evaluated on a low carbon steel, containing ellipsoidal defects with different orientations, under tension and torsion fatigue loadings.

Adaptive Green-Kubo estimates of transport coefficients from molecular dynamics based on robust error analysis

We present a rigorous Green-Kubo methodology for calculating transport coefficients based on on-the-fly estimates of: (a) statistical stationarity of the relevant process, and (b) error in the resulting coefficient. The methodology uses time samples efficiently across an ensemble of parallel replicas to yield accurate estimates, which is particularly useful for estimating the thermal conductivity of semi-conductors near their Debye temperatures where the characteristic decay times of the heat flux correlation functions are large. Employing and extending the error analysis of Zwanzig and Ailawadi [Phys. Rev. 182, 280 (1969)] and Frenkel [in Proceedings of the International School of Physics "Enrico Fermi", Course LXXV (North-Holland Publishing Company, Amsterdam, 1980)] to the integral of correlation, we are able to provide tight theoretical bounds for the error in the estimate of the transport coefficient. To demonstrate the performance of the method, four test cases of increasing computational cost and complexity are presented: the viscosity of Ar and water, and the thermal conductivity of Si and GaN. In addition to producing accurate estimates of the transport coefficients for these materials, this work demonstrates precise agreement of the computed variances in the estimates of the correlation and the transport coefficient with the extended theory based on the assumption that fluctuations follow a Gaussian process. The proposed algorithm in conjunction with the extended theory enables the calculation of transport coefficients with the Green-Kubo method accurately and efficiently.

ZFP423 Coordinates Notch and Bone Morphogenetic Protein Signaling, Selectively Up-regulating Hes5 Gene Expression

Zinc finger protein 423 encodes a 30 Zn-finger transcription factor involved in cerebellar and olfactory development. ZFP423 is a known interactor of SMAD1-SMAD4 and of Collier/Olf-1/EBF proteins, and acts as a modifier of retinoic acid-induced differentiation. In the present article, we show that ZFP423 interacts with the Notch1 intracellular domain in mammalian cell lines and in Xenopus neurula embryos, to activate the expression of the Notch1 target Hes5/ESR1. This effect is antagonized by EBF transcription factors, both in cultured cells and in Xenopus embryos, and amplified in vitro by BMP4, suggesting that ZFP423 acts to integrate BMP and Notch signaling, selectively promoting their convergence onto the Hes5 gene promoter.

An answer to Hermann's conjecture on Bleimann–Butzer–Hahn operators

We give a negative answer to the conjecture of Hermann [On the operator of Bleimann, Butzer and Hahn, in: J. Szabados, K. Tandori (Eds.), Approximation Theory, Proc. Conf., Kecskemét/Hung., 1990, North-Holland Publishing Company, Amsterdam, 1991, Colloq. Math. Soc. János Bolyai 58 (1991) 355–360] on Bleimann–Butzer–Hahn operators L n . Our main result states that for each locally bounded positive function h there exists a continuous positive function f defined on [ 0 , ∞ ) with L n f → f ( n → ∞ ) , pointwise on [ 0 , ∞ ) , such that lim sup x → + ∞ f ( x ) h ( x ) =+ ∞ . Moreover we construct an explicit counterexample function to Hermann's conjecture.

Prevention of Tissue Death by Killer Cells?

Based on the observation that mouse strains differing in lymphocyte-mediated immune responses differed also markedly in collateral density, in their ability to develop a collateral circulation, in remodeling and the expression of VEGF-A after femoral artery occlusion, previously reported by Scholz et al,1 Chalothorn,2 and Helisch et al,3 van Weel et al had set out to test the role of lymphocytes in arteriogenesis.4 They found that NK-cells and CD4 cells are important for collateral vessel growth and that substitution in animals deficient for these cells accelerated collateral development. These elegant studies, using mouse genetics as well as antibody-based deletion experiments, provide a solution to a long smoldering discussion about the role of lymphocytes in arteriogenesis as well as in angiogenesis. As early as 1976 Klintworth and collaborators5 showed that angiogenesis in response to corneal injury was associated with an influx of leukocytes. The causal relationship was proven by irradiation to depress the bone marrow leading to impaired angiogenesis. The contribution of subsets of leukocytes was difficult to discern at the time because …

Human factor—Factor human

The fatigue design of metallic parts depends on the casting process. It requires a compromise between the fatigue resistance of the component and the allowable defect size due to the process. The research team has proposed, in previous work [Leopold G, Nadot Y. J ASTM Int 7:2010], to represent the effect of a defect in the fatigue criterion by means of a stress gradient term. This general methodology called Defect Stress Gradient (DSG) can consider explicitly the type, the morphology and the size of the defect due to the fact that a Finite Element (FE) submodel describes directly the defect at the mesoscopic scale. The DSG approach gives correct results for the defects range from 100 to 1000 μm but it is limited for application to full scale components by the use of FE submodel. The aim of this paper is to present an upgraded version of the DSG approach using the Equivalent Inclusion Method (EIM) due to Eshelby [Eshelby JD. Proc Royal Soc Lond Ser A. Math Phys Sci 241:1957; 376–96], [Eshelby JD. Elastic inclusions and inhomogeneities. In: Sneddon IN, Hill R (Eds.), Progress in solid mechanics 2. Amsterdam: North-Holland Publishing Company; 1961. p. 89–140] to compute stresses around the defect. Using this analytical approach, it is possible to compute the stresses around an ellipsoidal defect without FE simulations. Furthermore, the EIM for an ellipsoidal defect is efficient to address the question of the defect size related to loading direction in the case of a non-spherical defect. Although the framework of the original EIM is for internal defect, this paper shows that its application for a surface defect gives fair results in the context of the DSG approach. The new DSG proposal is evaluated on a low carbon steel, containing ellipsoidal defects with different orientations, under tension and torsion fatigue loadings.

Equivalents of the (Weak) Fan Theorem

This article presents a weak system of intuitionistic second-order arithmetic, WKV, a subsystem of the one in S.C. Kleene, R.E. Vesley [The Foundations of Intuitionistic Mathematics: Especially in Relation to Recursive Functions, North-Holland Publishing Company, Amsterdam, 1965]. It is then shown that some statements of real analysis, like a version of the Heine–Borel Theorem, and some statements of logic, e.g. compactness of classical proposition calculus, are equivalent to the (Weak) Fan Theorem in this system.

THREE-DIMENSIONAL WAVE PROPAGATION AND ENERGY FLOW

International Journal of Computational Engineering ScienceVol. 05, No. 03, pp. 481-494 (2004) No AccessTHREE-DIMENSIONAL WAVE PROPAGATION AND ENERGY FLOWKARL-HEINZ ELMERKARL-HEINZ ELMERCurt-Risch-Institute for Dynamics, Acoustics and Measurement Techniques, University of Hannover, Appelstr. 9a, D–30167 Hannover, Germany Search for more papers by this author https://doi.org/10.1142/S1465876304002526Cited by:0 PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail AbstractRealistic mechanical wave propagation problems and acoustic problems in transient dynamics with a broad frequency range require very large systems and many timesteps, to obtain reliable numerical solutions with sufficient high accuracy. New algorithms are to be developed to make effective use of todays hardware features and the visualization of complex prozesses like intensity and energy flow in transient dynamics.The propagation of mechanical waves is characterized by the change and interaction of strain energy and kinetic energy in space and time. A fast explicit FD-algorithm for wave propagation problems and acoustic problems is developed to analyse and visualise the complex behavior of traveling waves. This inherent parallel algorithm is based on the solution of the three-dimensional wave equation as a first order formulation in terms of stresses and velocities or acoustic pressure and particle velocity, representing both forms of energy in a direct way. Because of the small storage required and the short computational time, the algorithm allows numerical investigations of large systems with online graphic simulations to analyse the complex real physical behavior of propagating waves and to make numerical results comparable to measured results. Local mesh refinement helps to minimize numerical errors of the discrete model.Examples of applications are given with dispersional effects of traveling waves, instantaneous intensity distribution and local energy flow of propagating and standing waves. The complex behavior of traveling waves in a bar with a crack is analysed as a three-dimensional system. As a result, a non-destructive testing method is described using impact hammer for the detection, localization and quantification of cracks. The size of the defects can be of some order smaller than the used wave length. References J. D. Achenbach , Wave propagation in elastic solids ( North Holland Publishing Company , Amsterdam, New York, Oxford , 1980 ) . Google Scholar K.-H. Elmer. The complex behaviour of traveling waves and numerical methods. In Eurodyn 2002 Conf., München, Germany, 2002 . Google Scholar K.-H. Elmer. Parallel algorithm for three-dimensional wave propagation problems. In F. G. Rammerstorfer H. A. Mang and J. Eberhardsteiner, editors, WCCM V, Fifth World Congress on Computational Mechanics, Vienna, Austria, 2002 . Google ScholarK.-H. Elmer and H. G. Natke, RBCM J. of the Braz. Soc. Mechanical Sciences XX(4), 587 (1998). Google Scholar K.-H. Elmer and R. Schröder. Paralleler algorithmus zur simulation von wellenaus-breitungsvorgängen. In DFG-Abschlussbericht Na 139/32-2, 2000 . Google Scholar L. E. Kinsler et al. , Fundamentals of Acoustics ( John Wiley & Sons, Inc. , Amsterdam, New York, Oxford , 2000 ) . Google Scholar J. Miklowitz , The theory of elastic waves and waveguides ( North Holland Publishing Company , Amsterdam , 1978 ) . Google ScholarG. Pavic, Journal of Sound and Vibration 115(3), 405 (1987). Crossref, Google Scholar J. C. Strikwerda. Finite difference schemes and partial differential equations. Wadsworth & Brooks/Cole Mathematics Series, Pacific Grove, 1989 . Google ScholarN.-E. Wiberg and X. D. Li, International journal for numerical methods in engineering 46, 1781 (1999). Crossref, Google ScholarO. C. Zienkiewicz, Int. J. Num. Meth. Eng. 47, 9 (2000). Crossref, Google ScholarO. C. Zienkiewicz and Y. M. Xie, Earthquake Eng. Struct. Dyn. 20, 871 (1991). Crossref, Google Scholar FiguresReferencesRelatedDetails Recommended Vol. 05, No. 03 Metrics History PDF download

Stochastic integration with respect to compensated Poisson random measures on separable Banach spaces

We define stochastic integrals of Banach valued random functions w.r.t. compensated Poisson random measures. Different notions of stochastic integrals are introduced and sufficient conditions for their existence are established. These generalize, for the case where integration is performed w.r.t. compensated Poisson random measures, the notion of stochastic integrals of real valued random functions introduced in Ikeda and Watanabe (1989) [Stochastic Differential Equations and Diffusion Processes (second edition), North-Holland Mathematical Library, Vol. 24, North Holland Publishing Company, Amsterdam/Oxford/New York.], (in a different way) in Bensoussan and Lions (1982) [Contróle impulsionnel et inquations quasi variationnelles. (French) [Impulse control and quasivariational inequalities] Méthodes Mathématiques de l'Informatique [Mathematical Methods of Information Science], Vol. 11. (Gauthier-Villars, Paris), and Skorohod, A.V. (1965) [Studies in the theory of random processes (Addison-Wesley Publishing Company, Inc, Reading, MA), Translated from the Russian by Scripta Technica, Inc. ], to the case of Banach valued random functions. The relation between these two different notions of stochastic integrals is also discussed here.

IN MEMORIAM: Dr. An Tzu Yang (1923–2003)

IN MEMORIAM: Dr. An Tzu Yang (1923–2003)

Kernels in digraphs with covering number at most 3

A kernel N of a digraph D is an independent set of vertices of D such that for every x∈ V( D)− N there exists an arc from x to N. A digraph D is M-oriented if each directed triangle has at least two symmetrical arcs. The covering number of a digraph D denoted by θ( D) is the minimum number of complete subdigraphs of D that partition V( D). Let D be an M-oriented digraph with θ( D)⩽3. In this paper the following result is proved: If each directed cycle C of length 5 satisfies at least one of the two following properties: (a) C has two diagonals (b) C has three symmetrical arcs. Then D has a kernel. This result generalizes the previous results and as a consequence the following interesting conjecture is proved (now known to be false in general) in case that D is a digraph with θ( D)⩽3. [ Meyniel, 1976]Conjecture 1 [M. Blidia, P. Duchet, F. Maffray, On the orientation of Meyniel graphs, J. Graph Theory 18(7) (1994) 705–711; P. Duchet, Graphes Noyau-Parfaits, Ann. Discrete Math. 9 (1980) 93–101, North-Holland Publishing Company]. If every directed cycle of odd length contained in D possesses two diagonals, then D has a kernel.

James E. Baumgartner, Alan Taylor, and Stanley Wagon. Ideals on uncountable cardinals. Logic Colloquium '77, Proceedings of the colloquium held in WrocŁaw, August 1977, edited by Angus Macintyre, Leszek Pacholski, and Jeff Paris, Studies in logic and the foundations of mathematics, vol. 96, North-Holland Publishing Company, Amsterdam, New York, and Oxford, 1978, pp. 67–77. - J. E. Baumgartner, A. D.

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Ankylosing spondylitis, HLA B27, and beyond

Publication of the landmark Lancet paper showing the strong association between HLA B27 and ankylosing spondylitis 25 years ago 1 Brewerton DA Hart FD Nicholls A Caffrey M James DCO Sturrock RD Ankylosing spondylitis and HLA-27. Lancet. 1973; ii: 904-907 Summary Scopus (1410) Google Scholar stimulated an avalanche of research into HLA/disease associations. The subsequent weaker associations of HLA B27 with anterior uveitis, reactive arthritis, sacroiliitis, late-onset pauciarticular juvenile chronic arthritis in boys, and inflammatory bowel disease with axial joint involvement suggested a common genetic determinant for a group of disorders already linked as seronegative spondyloarthropathies by the clinical observations and family studies of the late Verna Wright, 2 Wright V Moll JMH Seronegative polyarthritis. North Holland Publishing Company, Amsterdam1976: 1-483 Google Scholar and others. Because reactive arthritis can be precipitated in B27-positive individuals by sexually acquired chlamydial infection or by enteric infections with Campylobacter, Clostridium, Salmonella, Shigella, and Yersinia spp, induction of disease by “arthritogenic” bacterial strains in genetically predisposed individuals has become a compelling idea for the pathogenesis of these disorders. This idea is supported by experiments in transgenic rats expressing HLA B27 and human β2-microglobulin. Such animals develop gut and joint inflammatory disease, 3 Hammer RE Maika SD Richardson JA Tang JP Taurog JD Spontaneous inflammatory disease in transgenic rats expressing HLA B27 and human β2m: an animal model of HLA B27 associated with human disorders. Cell. 1990; 63: 1099-1112 Summary Full Text PDF PubMed Scopus (814) Google Scholar which is mediated by normal gut bacteria, including Bacteroides species, 4 Rath HC Herfarth HH Ikeda JS et al. Normal luminal bacteria, especially bacteroides species, mediate chronic colitis, gastritis, and arthritis in HLA B27/human beta2 microglobulin transgenic rats. J Clin Invest. 1996; 98: 945-953 Crossref PubMed Scopus (677) Google Scholar and which does not occur when the animals are maintained in a germfree environment. 5 Taurog JD Richardson JA Croft JT et al. The germ free state prevents development of gut and joint inflammatory disease in HLA B27 transgenic rats. J Exp Med. 1994; 180: 2359-2364 Crossref PubMed Scopus (914) Google Scholar

Three-Dimensional Boundary Value Problems of Elastothermodiffusion with Mixed Boundary Conditions

Abstract We investigate the basic boundary value problems of the connected theory of elastothermodiffusion for three-dimensional domains bounded by several closed surfaces when the same boundary conditions are fulfilled on every separate boundary surface, but these conditions differ on different groups of surfaces. Using the results of papers [Kupradze, Gegelia, Basheleishvili, and Burchuladze, Three-dimensional problems of the mathematical theory of elasticity and thermoelasticity, North-Holland Publishing Company, 1979, Russian original, 1976–Mikhlin, Multi-dimensional singular integrals and integral equations, 1962], we prove theorems on the existence and uniqueness of the classical solutions of these problems.

Automating Algebraic Proofs in Algebraic Logic

We present here an effective proof theory that allows one to reason within algebras of algebraic logic in a purely syntactic, algebraic fashion. We demonstrate the effectiveness of the method by discussing our automated proofs of problems and theorems taken from Professor Helena Rasiowa's book An Algebraic Approach to Non-Classical Logics, Studies in Logic and Fundation of Mathematics, Volume 78, North Holland Publishing Company, Amsterdam, London - PWN, Warsaw (1974). We include a detailed proof of a problem presented to us by Professor Helena Rasiowa in June 1993. Most of these proofs are the first direct proofs ever discovered, and they are produced by the computer without human assistance.

Harmful effects of seemingly helpful information on forecasts of stock earnings : Fred D. Davis (University of Minnesota), Gerald L. Lohse (University of Pennsylvania), and Jeffrey E. Kottemann (Salisbury State University)


 
 
 Decision makers have expanding access to business information via computerized news retrieval systems. A greater understanding is needed about how this news retrieval informa- tion influences their performance and confidence. MBA students from an advanced finance course forecasted stock earnings using a computerized information system designed to simulate systems used in practice. Disguised actual company data were presented in three different treatments: baseline information, baseline plus redundant news information, and baseline plus nonredundant news information. The redundant information made subjects significantly more confident in their forecasts compared to the baseline case. The nonredun- dam information made subjects significantly more confident than both the baseline case and the redundant case. Forecast accuracy, however, was significantly diminished in both the redundant and nonredundant conditions compared to baseline. Thus, the additional news information, whether redundant or nonredundant, had the effect of degrading performance while increasing confidence. This indicates that decision makers may be poor judges of the usefulness of newly available information sources, and may be influenced by information that does not improve their performance under the false impression that it is helpful. Journal of Economic Psychology, June 1994, 15(2): 253-267. (Reprinted with permission of North Holland Publishing Company.)