Why De Anima Needs III.12-13

The soul is an explanatory principle of Aristotle’s natural science, accounting both for the fact that living things are alive as well as for the diverse natural attributes that belong to them by virtue of being alive. I argue that the explanatory role of the soul in Aristotle’s natural science must be understood in light of his view, stated in a controversial passage from Parts of Animals (645b14–20), that the soul of a living thing is a “complex activity” of its organic body. This paper explores the role of this “complex activity” model of soul in Aristotle’s study of soul in De Anima. I argue, first, that the model has its origins in De Anima II.4, where Aristotle argues that living things do all they do by nature for the sake of a single, teleologically primary end. I argue further that Aristotle uses this model to account for the psychological attributes naturally present in living things, including their capacities for vital activities like nutrition, reproduction, and perception, and that this is the task to which Aristotle devotes the obscure final chapters of De Anima III

Cytokinin response factor 6 represses cytokinin-associated genes during oxidative stress

Cytokinin is a phytohormone that is well known for its roles in numerous plant growth and developmental processes, yet it has also been linked to abiotic stress response in a less defined manner. Arabidopsis (Arabidopsis thaliana) Cytokinin Response Factor 6 (CRF6) is a cytokinin-responsive AP2/ERF-family transcription factor that, through the cytokinin signaling pathway, plays a key role in the inhibition of dark-induced senescence. CRF6 expression is also induced by oxidative stress, and here we show a novel function for CRF6 in relation to oxidative stress and identify downstream transcriptional targets of CRF6 that are repressed in response to oxidative stress. Analysis of transcriptomic changes in wild-type and crf6 mutant plants treated with H2O2 identified CRF6-dependent differentially expressed transcripts, many of which were repressed rather than induced. Moreover, many repressed genes also show decreased expression in 35S:CRF6 overexpressing plants. Together, these findings suggest that CRF6 functions largely as a transcriptional repressor. Interestingly, among the H2O2 repressed CRF6-dependent transcripts was a set of five genes associated with cytokinin processes: (signaling) ARR6, ARR9, ARR11, (biosynthesis) LOG7, and (transport) ABCG14. We have examined mutants of these cytokinin-associated target genes to reveal novel connections to oxidative stress. Further examination of CRF6-DNA interactions indicated that CRF6 may regulate its targets both directly and indirectly. Together, this shows that CRF6 functions during oxidative stress as a negative regulator to control this cytokinin-associated module of CRF6-dependent genes and establishes a novel connection between cytokinin and oxidative stress response

Pathogen Manipulation of Arabidopsis Interaction Networks

Under normal conditions, plants devote resources for growth, development, and reproduction. These processes require finely tuned coordination between multiple physio logical pathways. In this dissertation, we explore the connectivity of these pathways as well as what happens when the plant is challenged by biotic stress such as a bacterial pathogen. We are able to use network biology approaches in conjunction with yeast two hybrid and BiFC assays to construct a network of leucine-rich repeat receptor kinases. Furthermore, we elucidated novel effector-host interactions through the aforementioned network. Lastly, we explored the role of the glyoxylate cycle, in particular peroxisomal citrate synthase (CSY2 and CSY3), in leaf senescence and plant defense. We discovered peroxisomal citrate synthase is transcriptionally up regulated during both processes. Ad ditionally, mutants lacking peroxisomal citrate synthase showed a delay in the onset of senescence and an increase in plant resistance to virulent pathogens. Lastly, we were able to identify ASR3 as a negative regulator of CSY2 and CSY3 gene expression during se nescence and biotic stress. ASR3 transcripts decreased during both processes. Overall, this work demonstrates the interaction between developmental processes and biotic stress response in plants

Aristotle's Case for Perceptual Knowledge

Sense experience, naïvely conceived, is a way of knowing perceptible properties: the colors, sounds, smells, flavors, and textures in our perceptual environment. So conceived, ordinary experience presents the perceiver with the essential nature of a property like Sky Blue or Middle C, such that how the property appears in experience is identical to how it essentially is. In antiquity, as today, it was controversial whether sense experience could meet the conditions for knowledge implicit in this naïve conception. Aristotle was a partisan in this debate, but his position is poorly understood. This dissertation examines how Aristotle’s perceptual psychology responds to ancient challenges to the naïve conception, and so articulates his defense of perceptual knowledge. Aristotle’s defense relies on an ontology of “perceptual qualities"—a core class of perceptible properties—according to which those qualities, despite having a perceiver-independent essence rooted in the physics of causation and affection, nevertheless can be present in experience as they essentially are. Chapter 1 defends this realist and objectivist reading against competing interpretations, which overlook a crucial distinction between perceptual qualities and perceptual objects. Chapter 2 presents Aristotle’s ontology as a physicalism that uncharacteristically allows for perceptual qualities to appear in experience as they essentially are. This ontology informs Aristotle’s account of the psychological conditions under which perceivers actually are presented with the essence of perceptual qualities. The locus of this account is an obscure passage where Aristotle purports to show that the senses “discriminate” perceptual qualities because the senses are “mean states” (An. 2.11, 424a5–7). Chapter 3 develops a comprehensive interpretation of the sensory mean state, which Chapter 4 uses to elucidate Aristotle’s argument for sensory discrimination. Sensory discrimination turns out to be a process in which the essence of a perceptual quality comes to be present in the affection it produces in a perceiver. For Aristotle, this shows that sense perception meets a condition for knowledge that his predecessors, including Plato, thought it could not meet. For in his view, but not in theirs, sense experience shares in both the truth and the essence of the qualities it perceives

Information Asymmetries And Closed-End Funds

We examine the degree to which information asymmetries play a role in the closed-end fund seasoned offerings and introduce a new explanation for why funds with low information asymmetry also choose to issue.  Interpreting turnover ratio as a proxy for information asymmetry, we test for differences in turnover across fund types and find that equity and international fund issuers generate significantly higher turnover than debt and domestic fund issuers respectively. We then investigate the motives for issuing funds with low information asymmetry and discover that they are good asset market timers, i.e. issue when underlying asset markets are relatively underpriced. By timing asset markets, such funds generate better long-run returns and maximize the interests of long-term investors

A Computational Electrostatic Modeling Pipeline for Comparing pH-dependent gp120-CD4 Interactions in Founder and Chronic HIV Strains

Though Human Immunodeficiency Virus has been studied for several decades, a consistentlyeffective vaccine has not yet been produced. While most experimental and computationalwork in this area has been performed under slightly basic conditions (eg. blood/-plasma), the viral transmission event generally occurs at the highly acidic mucosa. SincepH can greatly affect protein structure, it likely affects epitope exposure to either inhibit orfacilitate transmission. In this thesis, a pipeline for analyzing the pH sensitivity of proteinproteininteractions is applied to the transmission critical interaction between the HIV gp120and host CD4 proteins. The interaction between gp120 and CD4 is shown to be strongerat low pH for all strains tested, which is consistent with previous work and supports theaccuracy of the introduced pipeline. Also, early transmitted founder (TF) strains generallybind CD4 better at low pH and are more pH sensitive than systemically circulating chroniccontrol (CC) strains.M.S

International Regulation of Commercial Whaling: The Consequences of Norway\u27s Decision to Hunt the Minke Whale

In 1993 Norway announced its intention to resume commercial whaling despite an international whaling moratorium in effect since 1986. This moratorium has been rendered worthless by Norway\u27s insistence that it is within its legal rights, and by the dependence of the International Whaling Commission on the United States to enforce the Commission\u27s decisions. As other whaling countries make plans to follow Norway\u27s lead, it is necessary to find a way to effectively regulate whaling before it results in the extinction of the great whales. This Note explores the background of the International Whaling Commission, analyzes the whaling moratorium and Norway\u27s reaction to it, and finally evaluates possible solutions to this international dilemma