Narrower corn row widths, higher crop densities, and interrow cultivation may be used as part of integrated weed management (IWM). During a three-year study, we tested whether these factors affected corn growth, development and grain yield at final harvest, and weed biomass when weeds were late-emerging (after the three-leaf stage of corn). Increasing corn density from 7 to 10 plants m−2or decreasing row width from 75 to 50 cm significantly increased corn leaf area index (LAI), and reduced photosynthetic photon flux density (PPFD) available for a mixture of weed species located below the corn canopy. Narrower rows and higher corn density significantly reduced biomass of late-emerging weeds. Corn yields increased significantly (10 to 15%) only when narrower rows were used. Intraspecific competition between corn plants in the higher density significantly reduced early corn growth and offset any gain in yield from reduced weed competition. In comparison to plots where late-emerging weeds grew uncontrolled, interrow cultivation did not decrease biomass of late-emerging weeds, hence did not increase corn yield. We recommend using narrower row widths to reduce weed competition and increase corn yield. Increased corn densities had no net yield benefit. Early-season weed management is crucial as the later-emerging weeds were less important in terms of their effect on yield.
Gettier (1963) presented the now famous Gettier problem as a challenge to epistemology. The methods Gettier used to construct his challenge, however, utilized certain principles of formal logic that are actually inappropriate for the natural language discourse of the Gettier cases. In that challenge to epistemology, Gettier also makes truth claims that would be considered controversial in analytic philosophy of language. The Gettier challenge has escaped scrutiny in these other relevant academic disciplines, however, because of its façade as an epistemological analysis. This article examines Gettier's methods with the analytical tools of logic and analytic philosophy of language.
The theoretical heuristic of assuming distinct alleles (or genotypes) for alternative phenotypes is the foundation of the paradigm of evolutionary explanation we call the Modern Synthesis. In modeling the evolution of sociality, the heuristic has been to set altruism and selfishness as alternative phenotypes under distinct genotypes, which has been dubbed the ''phenotypic gambit.'' The prevalence of the altruistic genotype that is of lower evolutionary fitness relative to the alternative genotype for non-altruistic behavior in populations is the basis of the ''paradox of altruism.'' I show in this article that the assumption of contrasting genotypes for altruism and selfishness in our ''phenotypic gambit'' is inconsistent with the empirical data when viewed in the light of today's post-Mendelian understanding of gene expression. I demonstrate that however nuanced and sophisticated the models may have become today, they are still rooted in that fundamentally problematic assumption. I then offer a genetic conception of altruism that best fits the field data.
In this article, I use Edmund Gettier's Ten Coins hypothetical scenario to illustrate some reasoning errors in the use of definite descriptions. The Gettier problem, central as it is to modern epistemology, is first and foremost an argument, which Gettier (1963) constructs to prove a contrary conclusion to a widely held view in epistemology. Whereas the epistemological claims in the case have been extensively analysed conceptually, the strategies and tools from other philosophical disciplines such as analytic philosophy of language, logic and argumentation that Gettier deploys in the case have scarcely received any attention. This work abstracts from the epistemological content and examines Gettier's handling of the definite description involved, and how that affects the cogency of his argument.
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