Home  About us  Contact
 

Heuristic Framework (heuristic + framework)

Distribution by Scientific Domains
Humanities and Social Sciences40%

Selected Abstracts

Anteroposterior patterning in the limb and digit specification: Contribution of mouse genetics

DEVELOPMENTAL DYNAMICS, Issue 9 2006
Benoît Robert
Abstract The limb has been a privileged object of investigation and reflection for scientists over the past two centuries and continues to provide a heuristic framework to analyze vertebrate development. Recently, accumulation of new data has significantly changed our view on the mechanisms of limb patterning, in particular along the anterior-posterior axis. These data have led us to revisit the mode of action of the zone of polarizing activity. They shed light on the molecular and cellular mechanisms of patterning linked to the Shh-Gli3 signaling pathway and give insights into the mechanism of activation of these cardinal factors, as well as the consequences of their activity. These new data are in good part the result of systematic Application of tools used in contemporary mouse molecular genetics. These have extended the power of mouse genetics by introducing mutational strategies that allow fine-tuned modulation of gene expression, interchromosomal deletions and duplication. They have even made the mouse embryo amenable to cell lineage analysis that used to be the realm of chick embryos. In this review, we focus on the data acquired over the last five years from the analysis of mouse limb development and discuss new perspectives opened by these results. Developmental Dynamics 235:2337,2352, 2006. © 2006 Wiley-Liss, Inc. [source]

What Does It Mean to Be Relational?

FAMILY PROCESS, Issue 4 2006
A Framework for Assessment, Practice
The authors begin with a question regarding how to better draw upon relational thinking in making case assessments and treatment plans. They first address issues regarding the cultural construction of self and relationships, integrating women's psychology, family systems, and collectivist culture literatures within a discussion of power. Then they present a heuristic framework for how individuals orient themselves within relationships that includes two dimensions,focus and power,and evolves out of the social context. From these two dimensions, a typology of four basic relational orientations is presented: position directed, rule directed, independence directed, and relationship directed. Case examples from couple's therapy and suggestions for practice are provided. [source]

Backbone Diversity Analysis in Catalyst Design

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 3 2009

Abstract We present a computer-based heuristic framework for designing libraries of homogeneous catalysts. In this approach, a set of given bidentate ligand-metal complexes is disassembled into key substructures ("building blocks"). These include metal atoms, ligating groups, backbone groups, and residue groups. The computer then rearranges these building blocks into a new library of virtual catalysts. We then tackle the practical problem of choosing a diverse subset of catalysts from this library for actual synthesis and testing. This is not trivial, since ,catalyst diversity' itself is a vague concept. Thus, we first define and quantify this diversity as the difference between key structural parameters (descriptors) of the catalysts, for the specific reaction at hand. Subsequently, we propose a method for choosing diverse sets of catalysts based on catalyst backbone selection, using weighted D-optimal design. The computer selects catalysts with different backbones, where the difference is measured as a distance in the descriptors space. We show that choosing such a D-optimal subset of backbones gives more diversity than a simple random sampling. The results are demonstrated experimentally in the nickel-catalysed hydrocyanation of 3-pentenenitrile to adiponitrile. Finally, the connection between backbone diversity and catalyst diversity, and the implications towards in silico catalysis design are discussed. [source]

An ejection chain algorithm for the quadratic assignment problem

NETWORKS: AN INTERNATIONAL JOURNAL, Issue 3 2010
Cesar Rego
Abstract In this study, we present a new tabu search algorithm for the quadratic assignment problem (QAP) that utilizes an embedded neighborhood construction called an ejection chain. Our ejection chain approach provides a combinatorial leverage effect, where the size of the neighborhood grows multiplicatively while the effort of finding a best move in the neighborhood grows only additively. Our results illustrate that significant improvement in solution quality is obtained in comparison to the traditional swap neighborhood. We also develop two multistart tabu search algorithms utilizing the ejection chain approach in order to demonstrate the power of embedding this neighborhood construction within a more sophisticated heuristic framework. Comparisons to the best large neighborhood approaches from the literature are presented. © 2009 Wiley Periodicals, Inc. NETWORKS, 2010 [source]

The diverse and contested meanings of sustainable development

THE GEOGRAPHICAL JOURNAL, Issue 2 2004
Colin C Williams
We provide a heuristic framework that can be used as a lens for understanding the arguments being presented in the papers which comprise this special issue on sustainable development and environmental issues in Great Britain. This framework can also be used as an introduction to the wider literature on sustainable development because it is designed to bring greater clarity to this large, diverse and rapidly expanding field of enquiry populated by heterogeneous discourses, multiple approaches and a variety of recommendations as to the ways forward. [source]