Multiple memory systems are unnecessary to account for infant memory development: An ecological model.

How the memory of adults evolves from the memory abilities of infants is a central problem in cognitive development. The popular solution holds that the multiple memory systems of adults mature at different rates during infancy. The early-maturing system (implicit or nondeclarative memory) functions automatically from birth, whereas the late-maturing system (explicit or declarative memory) functions intentionally, with awareness, from late in the first year. Data are presented from research on deferred imitation, sensory preconditioning, potentiation, and context for which this solution cannot account and present an alternative model that eschews the need for multiple memory systems. The ecological model of infant memory development (N. E. Spear, 1984) holds that members of all species are perfectly adapted to their niche at each point in ontogeny and exhibit effective, evolutionarily selected solutions to whatever challenges each new niche poses. Because adults and infants occupy different niches, what they perceive, learn, and remember about the same event differs, but their raw capacity to learn and remember does not. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Optimal left and right additive Schwarz preconditioning for minimal residual methods with Euclidean and energy norms

For the solution of non-symmetric or indefinite linear systems arising from discretizations of elliptic problems, two-level additive Schwarz preconditioners are known to be optimal in the sense that convergence bounds for the preconditioned problem are independent of the mesh and the number of subdomains. These bounds are based on some kind of energy norm. However, in practice, iterative methods which minimize the Euclidean norm of the residual are used, despite the fact that the usual bounds are non-optimal, i.e., the quantities appearing in the bounds may depend on the mesh size; see [X.-C. Cai, J. Zou, Some observations on the l² convergence of the additive Schwarz preconditioned GMRES method, Numer. Linear Algebra Appl. 9 (2002) 379-397]. In this paper, iterative methods are presented which minimize the same energy norm in which the optimal Schwarz bounds are derived, thus maintaining the Schwarz optimality. As a consequence, bounds for the Euclidean norm minimization are also derived, thus providing a theoretical justification for the practical use of Euclidean norm minimization methods preconditioned with additive Schwarz. Both left and right preconditioners are considered, and relations between them are derived. Numerical experiments illustrate the theoretical developments.     

Spectral-element preconditioners for the uzawa pressure operator applied to incompressible flows

Seven preconditioners for the Uzawa pressure operator are discussed in the context of the spectral-element discretization of unsteady, incompressible flows. An already existing algorithm, based on decomposition of the pressure operator, is modified in order to reduce the number of iterations and cpu time. A twostage preconditioning technique is set up to solve efficiently problems at high Reynold numbers. The performance of the preconditioners is tested on a number of Stokes and Navier-Stokes problems in three dimensions.     

Post-harvest pod storage: A method for pulp preconditioning to impair strong nib acidification during cocoa fermentation in Malaysia

In Malaysia, pulp preconditioning by post-harvest storage of cocoa pods leads to the reduction of nib acidification during subsequent fermentation, reduction of the acid note and an increase in cocoa flavour in the resulting raw cocoa. Data from several shallow-box fermentations, with material from unstored and stored pods, are compared and interpreted, obtained in the years 1984 to 1987 in a cooperational investigation of the Malaysian Agricultural Research and Development Institute (MARDI), Malaysia, and the Botanical Institute, Technical University of Braunschweig (TUBS), FRG. Prior to and during fermentation, pulp volume and pulp sugars; pH value, acetic acid and lactic acid content in the pulp and nibs; and oxygen concentration and temperature in the mass were determined. Some flavour assessments from selected samples are given. The great reduction in pulp volume per seed rather than the decrease of pulp sugars per seed during pod storage was found to be of the most importance. Pulp-volume reduction enhances mass aeration and increases the ratio of respiration to ethanol fermentation and its subsequent oxidation to acetic acid. As a consequence, the acidification of the seeds during the formative stages of flavour precursors (after the death of the seeds) is strongly reduced. With effectively dry stored pods (pulp volume per gram of seed ≤0·6 ml) the anaerobic phase during the initial stages of fermentation which is common with unstored pods is suppressed. Under these conditions the nib pH value does not fall below 5·0 and no drastic acid (and flavour) degradation at the end of fermentation is necessary to reduce the acidity in the seeds.     

On the Solution of Boundary Value Problems by Using Fast Generalized Approximate Inverse Banded Matrix Techniques

A class of finite difference schemes in conjunction with approximate inverse banded matrix techniques based on the concept of LU-type factorization procedures is introduced for computing fast explicit approximate inverses. Explicit preconditioned iterative schemes in conjunction with approximate inverse matrix techniques are presented for the efficient solution of banded linear systems. A theorem on the rate of convergence and estimates of the computational complexity required to reduce the L-norm of the error is presented. Applications of the method on linear and non-linear systems are discussed and numerical results are given.     

基于预处理方法的流动数值分析

以预处理方法为基础,采用了有限体积法,并将高精度高分辨率迎风格式与隐式时间推进法LU－SGS格式结合,对低速到超音速范围内的流动进行数值分析。为了提高AUSMPW^＋格式的计算精度,采用了三阶MUSCL格式,为了验证本方法对低速到超音速范围内的无粘和粘性流动的数值分析效果,对几个典型算例进行了数值试验。本的数值结果与献计算结果和实验数据基本一致,表明本方法可以有效地对低速到超音速范围内的流动进行数值分析。     

Macro-elementwise preconditioning methods

Extremely large scale problems, modelled by partial differential equations, arise in various applications, and must be solved by properly preconditioned iterative methods. Frequently, the corresponding medium is heterogeneous. Recursively constructed two-by-two block matrix partitioning methods and elementwise constructed preconditioners for the arising pivot block and Schur complement matrices have turned out to be very efficient methods, and are analysed in this paper. Thereby special attention is paid to macroelementwise partitionings, which can be particularly efficient in the modelling of materials with large and narrow variations and can also provide efficient implementations on parallel computers.     

肢体缺血预处理对大鼠脊髓缺血再灌注损伤的作用及机制

目的探讨肢体缺血预处理对大鼠脊髓缺血再灌注损伤的作用及机制。方法将72只SD大鼠按随机数字表法分为3组：假手术组（Sham组）、缺血再灌注损伤组（I/R组）和缺血预处理组（LIPC组）,每组24只。Sham组仅暴露腹主动脉,不结扎;I/R组采用Zivin法建立脊髓缺血再灌注损伤模型,麻醉后夹闭左肾下腹主动脉30 min;LIPC组大鼠在麻醉后使用止血带阻断右下肢血运10 min,恢复血运10 min,反复2次后同I/R组办法建模。3组分别于手术缝合后6 h（T1）、1 d（T2）、3 d（T3）和7 d（T4）时随机抽取6只大鼠,采用改良Tarlov评分法进行下肢神经功能评分。各组在T1—T4时的评分结束后,取L2-4脊髓组织,行HE染色,双目光学显微镜下观察脊髓组织的病理变化,并采用免疫组织化学法检测脊髓组织中胶质纤维酸性蛋白（GFAP）的表达水平。结果与Sham组比较：I/R组、LIPC组大鼠T1—T3时改良Tarlov得分均明显降低（均P〈0.05）,T1—T4时大鼠GFAP表达水平均明显升高（P〈0.05）;与I/R组比较：LIPC组大鼠T1—T3时改良Tarlov得分,T2、T3时大鼠脊髓组织中GFAP表达水平均明显升高（均P〈0.05）。结论肢体缺血预处理有减轻大鼠脊髓缺血再灌注损伤的作用,其机制可能与GFAP表达上调有关。     

A parallel two‐level domain decomposition based one‐shot method for shape optimization problems

A two‐level domain decomposition method is introduced for general shape optimization problems constrained by the incompressible Navier–Stokes equations. The optimization problem is first discretized with a finite element method on an unstructured moving mesh that is implicitly defined without assuming that the computational domain is known and then solved by some one‐shot Lagrange–Newton–Krylov–Schwarz algorithms. In this approach, the shape of the domain, its corresponding finite element mesh, the flow fields and their corresponding Lagrange multipliers are all obtained computationally in a single solve of a nonlinear system of equations. Highly scalable parallel algorithms are absolutely necessary to solve such an expensive system. The one‐level domain decomposition method works reasonably well when the number of processors is not large. Aiming for machines with a large number of processors and robust nonlinear convergence, we introduce a two‐level inexact Newton method with a hybrid two‐level overlapping Schwarz preconditioner. As applications, we consider the shape optimization of a cannula problem and an artery bypass problem in 2D. Numerical experiments show that our algorithm performs well on a supercomputer with over 1000 processors for problems with millions of unknowns. Copyright © 2014 John Wiley & Sons, Ltd.