The focus of this study was to analyze the content, distribution, and comparative genome relationships of 996 chromosome bin-mapped expressed sequence tags accounting for 2266 restriction fragments on the homoeologous group 3 chromosomes of hexaploid wheat. Of these loci, 634, 884, and 748 were mapped on chromosomes 3A, 3B, and 3D, respectively. The individual chromosome bin maps revealed bins with a high density of mapped ESTs in the distal region and bins of low density in the proximal region of the (...) chromosome arms, with the exception of 3DS and 3DL. These distributions were more localized on the higher-resolution group 3 consensus map with intermediate regions of high-mapped-EST density on both chromosome arms. Gene ontology classification of mapped ESTs was not significantly different for homoeologous group 3 chromosomes compared to the other groups. A combined analysis of the individual bin maps using 537 of the mapped ESTs revealed rearrangements between the group 3 chromosomes. Approximately 232 of the consensus mapped ESTs matched sequences on rice chromosome 1 and revealed large- and small-scale differences in gene order. Of the group 3 mapped EST unigenes ∼21 and 32% matched the Arabidopsis coding regions and proteins, respectively, but no chromosome-level gene order conservation was detected. (shrink)

The complex hexaploid wheat genome offers many challenges for genomics research. Expressed sequence tags facilitate the analysis of gene-coding regions and provide a rich source of molecular markers for mapping and comparison with model organisms. The objectives of this study were to construct a high-density EST chromosome bin map of wheat homoeologous group 2 chromosomes to determine the distribution of ESTs, construct a consensus map of group 2 ESTs, investigate synteny, examine patterns of duplication, and assess the colinearity with rice (...) of ESTs assigned to the group 2 consensus bin map. A total of 2600 loci generated from 1110 ESTs were mapped to group 2 chromosomes by Southern hybridization onto wheat aneuploid chromosome and deletion stocks. A consensus map was constructed of 552 ESTs mapping to more than one group 2 chromosome. Regions of high gene density in distal bins and low gene density in proximal bins were found. Two interstitial gene-rich islands flanked by relatively gene-poor regions on both the short and long arms and having good synteny with rice were discovered. The map locations of two ESTs indicated the possible presence of a small pericentric inversion on chromosome 2B. Wheat chromosome group 2 was shown to share syntenous blocks with rice chromosomes 4 and 7. (shrink)

Schyns, Goldstone & Thibaut argue that categorization experience results in the learning of new perceptual features that are not derivable from the learner's existing feature set. We explore the meaning and implications of this “nonderivability” claim and relate it to the question of whether perceptual invariants are learnable, and if so, what might be entailed in learning them.

Humans, including preschool children, exhibit role-based relational reasoning, of which analogical reasoning is a canonical example. The connectionist model proposed in the target article is only capable of conditional paired-associate learning.

van der Velde & de Kamps argue for the importance of considering the binding problem in accounts of human mental representation. However, their proposed solution fails as a complete account because it represents the bindings between roles and their fillers through associations (or connections). In addition, many criticisms leveled by the authors towards synchrony-based bindings models do not hold.

The fundamental relations that underlie cognitive comparisons—“same” and “different”—can be defined at multiple levels of abstraction, which vary in relational complexity. We compared response times to decide whether or not two sequentially‐presented patterns, each composed of two pairs of colored squares, were the same at three levels of abstraction: perceptual, relational, and system (higher order relations). For both 150 ms and 5 s inter‐stimulus intervals (ISIs), both with and without a masking stimulus, decision time increased with level of abstraction. Sameness (...) at lower complexity levels contributed to decisions based on the higher levels. The pattern of comparison times across levelswas not predictable solely from encoding times. The results indicated that relations at multiple levels of complexity can be abstracted and compared in working memory, with higher complexity levels requiring more processing time. We simulated the impact of relational complexity on response time using Learning and Inference with Schemas and Analogies (LISA), a computational model of relational comparisons based on dynamic binding of elements into roles in a relational working memory. (shrink)

We are big fans of propositions. But we are not big fans of the proposed by Mitchell et al. The authors ignore the critical role played by implicit, non-inferential processes in biological cognition, overestimate the work that propositions alone can do, and gloss over substantial differences in how different kinds of animals and different kinds of cognitive processes approximate propositional representations.

Theories of analogical reasoning have viewed relational structure as the dominant determinant of analogical mapping and inference, while assigning lesser importance to similarity between individual objects. An experiment is reported in which these two sources of constraints on analogy are placed in competition under conditions of high relational complexity. Results demonstrate equal importance for relational structure and object similarity, both in analogical mapping and in inference generation. The human data were successfully simulated using a computational analogy model (LISA) that treats (...) both relational correspondences and object similarity as soft constraints that operate within a limited-capacity working memory; but not with a model (SME) that treats relational structure as pre-eminent. (shrink)

This report describes the rationale, approaches, organization, and resource development leading to a large-scale deletion bin map of the hexaploid wheat genome. Accompanying reports in this issue detail results from chromosome bin-mapping of expressed sequence tags representing genes onto the seven homoeologous chromosome groups and a global analysis of the entire mapped wheat EST data set. Among the resources developed were the first extensive public wheat EST collection. Described are protocols for sequencing, sequence processing, EST nomenclature, and the assembly of (...) ESTs into contigs. These contigs plus singletons were used for selection of distinct sequence motif unigenes. Selected ESTs were rearrayed, validated by 5′ and 3′ sequencing, and amplified for probing a series of wheat aneuploid and deletion stocks. Images and data for all Southern hybridizations were deposited in databases and were used by the coordinators for each of the seven homoeologous chromosome groups to validate the mapping results. Results from this project have established the foundation for future developments in wheat genomics. (shrink)

Limits to Action: The Allocation of Individual Behavior presents the ideas and methods in the study of how individual organisms allocate their limited time and energy and the consequences of such allocation. The book is a survey of individual resource allocation, emphasizing the relationships of the concepts of utility, reinforcement, and Darwinian fitness. The chapters are arranged beginning with plants and general evolutionary considerations, through animal behavior in nature and laboratory, and ending with human behavior in suburb and institution. Topics (...) discussed include operant conditioning; the principle of diminishing returns; and issues in relation to mating strategies. Biologists, sociologists, economists, and psychologists will find the book interesting. (shrink)

What are physical quantities, and in particular, what makes them quantitative? This book presents an original answer to this question through the novel position of substantival structuralism, arguing that quantitativeness is an irreducible feature of attributes, and quantitative attributes are best understood as substantival structured spaces.

Analogies must be symmetric. If a is like b, then b is like a. So if a has property R, and if R is within the scope of the analogy, then b (probably) has R. However, analogical arguments generally single out, or depend upon, only one of a or b to serve as the basis for the inference. In this respect, analogical arguments are directed by an asymmetry. I defend the importance of this neglected – even when explicitly mentioned – (...) feature in understanding analogical arguments. (shrink)

Manuscript Add. 3965, section 13, folios 541r–542r and 545r–546r is in the Portsmouth Collection of manuscripts and housed in the University Library, Cambridge. These drafts contain a careful account, in Newton's hand, of his views on place, time, and God. They are part of a large number of drafts relating to the three official editions of the Principia published in Newton's lifetime.

'To think often, and never to retain it so much as one moment, is a very useless sort of thinking' In An Essay concerning Human Understanding, John Locke sets out his theory of knowledge and how we acquire it. Eschewing doctrines of innate principles and ideas, Locke shows how all our ideas, even the most abstract and complex, are grounded in human experience and attained by sensation of external things or reflection upon our own mental activities. A thorough examination of (...) the communication of ideas through language and the conventions of taking words as signs of ideas paves the way for his penetrating critique of the limitations of ideas and the extent of our knowledge of ourselves, the world, God, and morals. Locke's masterpiece laid the foundation of British empiricism and is of enduring interest to anyone exploring the development of philosophical thought. This sensitive abridgement uses P. H. Nidditch's authoritative text, and together with an illuminating introduction and other features, makes Locke's arguments more accessible. (shrink)

: This article is concerned with Newton's appropriation of Descartes' ontology of true and immutable natures in developing his theory of infinitely extended space. It contends that unless the part played by the Platonic distinction between "being a nature" and "having a nature" in Newton's thinking is properly appreciated the foundation of his doctrine of space in relation to God will not be fully understood. It also contends that Newton's Platonism is consistent with his empiricism once the mediating role is (...) made clear that the geometry of moving loci play in grounding his intuitions concerning infinite natures. (shrink)

This book is available either individually, or as part of the specially-priced Arguments of the Philosphers Collection.