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Independent Support (independent + support)

Distribution by Scientific Domains
Humanities and Social Sciences40%

Selected Abstracts

Ecological selection against hybrids in natural populations of sympatric threespine sticklebacks

JOURNAL OF EVOLUTIONARY BIOLOGY, Issue 6 2007
J. L. GOW
Abstract Experimental work has provided evidence for extrinsic post-zygotic isolation, a phenomenon unique to ecological speciation. The role that ecological components to reduced hybrid fitness play in promoting speciation and maintaining species integrity in the wild, however, is not as well understood. We addressed this problem by testing for selection against naturally occurring hybrids in two sympatric species pairs of benthic and limnetic threespine sticklebacks (Gasterosteus aculeatus). If post-zygotic isolation is a significant reproductive barrier, the relative frequency of hybrids within a population should decline significantly across the life-cycle. Such a trend in a natural population would give independent support to experimental evidence for extrinsic, rather than intrinsic, post-zygotic isolation in this system. Indeed, tracing mean individual hybridity (genetic intermediateness) across three life-history stages spanning four generations revealed just such a decline. This provides compelling evidence that extrinsic selection plays an important role in maintaining species divergence and supports a role for ecological speciation in sticklebacks. [source]

THE PUZZLE OF FALLIBLE KNOWLEDGE

METAPHILOSOPHY, Issue 3 2008
HAMID VAHID
Abstract: Although the fallible/infallible distinction in the theory of knowledge has traditionally been upheld by most epistemologists, almost all contemporary theories of knowledge claim to be fallibilist. Fallibilists have, however, been forced to accommodate knowledge of necessary truths. This has proved to be a daunting task, not least because there is as yet no consensus on how the fallible/infallible divide is to be understood. In this article, after examining and rejecting a number of representative accounts of the notion of fallible knowledge, I argue that the main problems with these accounts actually stem from the very coherence of that notion. I then claim that the distinction is best understood in terms of the externalist/internalist conceptions of knowledge. Finally, I seek to garner some independent support for the proposal by highlighting some of its consequences, including its surprising bearing on certain recent and seemingly distant controversies involving issues in epistemology and philosophy of mind. [source]

INTENTIONALISM AND THE IMAGINABILITY OF THE INVERTED SPECTRUM

THE PHILOSOPHICAL QUARTERLY, Issue 224 2006
Eric Marcus
Various thought-experiments have been offered as independent support for the possibility of intentionalism-defeating spectrum inversion, but they do not succeed. I refute what I take to be the four best arguments for holding that the thought-experiments do in fact provide such support: the implausible error argument, the symmetry argument, the no-inference argument and the best theory of representation argument. I thus offer a defence of intentionalism against a long-standing objection. [source]

Covariate Adjusted Correlation Analysis with Application to,FMR1,Premutation Female Carrier Data

BIOMETRICS, Issue 3 2009
Damla, entürk
Summary Motivated by molecular data on female premutation carriers of the fragile X mental retardation 1 (FMR1) gene, we present a new method of covariate adjusted correlation analysis to examine the association of messenger RNA (mRNA) and number of CGG repeat expansion in the,FMR1,gene. The association between the molecular variables in female carriers needs to adjust for activation ratio (ActRatio), a measure which accounts for the protective effects of one normal X chromosome in females carriers. However, there are inherent uncertainties in the exact effects of ActRatio on the molecular measures of interest. To account for these uncertainties, we develop a flexible adjustment that accommodates both additive and multiplicative effects of ActRatio nonparametrically. The proposed adjusted correlation uses local conditional correlations, which are local method of moments estimators, to estimate the Pearson correlation between two variables adjusted for a third observable covariate. The local method of moments estimators are averaged to arrive at the final covariate adjusted correlation estimator, which is shown to be consistent. We also develop a test to check the nonparametric joint additive and multiplicative adjustment form. Simulation studies illustrate the efficacy of the proposed method. (Application to,FMR1,premutation data on 165 female carriers indicates that the association between mRNA and CGG repeat after adjusting for ActRatio is stronger.) Finally, the results provide independent support for a specific jointly additive and multiplicative adjustment form for ActRatio previously proposed in the literature. [source]

Symbolically speaking: a connectionist model of sentence production

COGNITIVE SCIENCE - A MULTIDISCIPLINARY JOURNAL, Issue 5 2002
Franklin Chang
Abstract The ability to combine words into novel sentences has been used to argue that humans have symbolic language production abilities. Critiques of connectionist models of language often center on the inability of these models to generalize symbolically (Fodor & Pylyshyn, 1988; Marcus, 1998). To address these issues, a connectionist model of sentence production was developed. The model had variables (role-concept bindings) that were inspired by spatial representations (Landau & Jackendoff, 1993). In order to take advantage of these variables, a novel dual-pathway architecture with event semantics is proposed and shown to be better at symbolic generalization than several variants. This architecture has one pathway for mapping message content to words and a separate pathway that enforces sequencing constraints. Analysis of the model's hidden units demonstrated that the model learned different types of information in each pathway, and that the model's compositional behavior arose from the combination of these two pathways. The model's ability to balance symbolic and statistical behavior in syntax acquisition and to model aphasic double dissociations provided independent support for the dual-pathway architecture. [source]