818 research outputs found

    Self-organization of intracellular gradients during mitosis

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    Gradients are used in a number of biological systems to transmit spatial information over a range of distances. The best studied are morphogen gradients where information is transmitted over many cell lengths. Smaller mitotic gradients reflect the need to organize several distinct events along the length of the mitotic spindle. The intracellular gradients that characterize mitosis are emerging as important regulatory paradigms. Intracellular gradients utilize intrinsic auto-regulatory feedback loops and diffusion to establish stable regions of activity within the mitotic cytosol. We review three recently described intracellular mitotic gradients. The Ran GTP gradient with its elaborate cascade of nuclear transport receptors and cargoes is the best characterized, yet the dynamics underlying the robust gradient of Ran-GTP have received little attention. Gradients of phosphorylation have been observed on Aurora B kinase substrates both before and after anaphase onset. In both instances the phosphorylation gradient appears to result from a soluble gradient of Aurora B kinase activity. Regulatory properties that support gradient formation are highlighted. Intracellular activity gradients that regulate localized mitotic events bare several hallmarks of self-organizing biologic systems that designate spatial information during pattern formation. Intracellular pattern formation represents a new paradigm in mitotic regulation

    Adorno, Hegel and the Philosophical Origins of Classical Social Theory

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    The central claim of my dissertation is that the work of Theodor Adorno offers a valuable framework for reevaluating the philosophical heritage of classical social theory. In his ongoing engagement with the philosophy of German Idealism, and with Hegel in particular, Adorno’s philosophical, sociological, and cultural critical writings involve a critical rethinking of the relationship between subject and object, and between individual and society. I make two primary arguments to substantiate my claim. The first is that Adorno’s work must be understood within the context of the philosophy of Kant and Hegel. In particular, I show that Hegel’s critique of Kantian philosophy structures Adorno’s own understanding of the work of philosophy and of critical social theory. In the first part of the dissertation, I review the substance of Kantian epistemology, and of Hegel’s critique (Chapter 2); I then demonstrate that the Adorno’s critical philosophical procedure is grounded in his reading of Kant and Hegel (Chapter 3). My second primary argument is that Adorno’s attempt to articulate a critique of classical social theory is hampered by his own philosophical commitments. Through a juxtaposition of Marx’s critique of Hegel’s practical philosophy with Adorno’s own critique of Hegel (Chapter 4), I show that Adorno’s commitment to the negativity of the dialectic entails a conception of social theory that has not sufficiently addressed the implications of its materialist transformation. Adorno’s work relies upon a reduction of Hegel that remains problematic and unacknowledged. Next, I use a reading of Durkheim’s own philosophical commitments, through the lens of German Idealism, to show that Adorno’s immanent critique of Durkheim reproduces the aporiae that it seeks to rescue (Chapter 5). In the conclusion to the thesis (Chapter 6), I employ a discussion of the common themes and problems of Adorno’s critical-philosophical interpretation of classical social theory to suggest a reconsideration and renewal of its Hegelian heritage

    A 21st Century Model For Ivy League Men’s Soccer: A Two-Semester Approach For The Benefit Of Student-Athletes

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    In June 2019, the Big Ten Conference announced that it would be sponsoring a proposal in the NCAA’s 2019-20 legislative cycle to implement a two-semester playing season for Division I Men’s Soccer called the 21st Century Model. If the new legislation were to pass, the Ivy League will need to decide how it will adjust its own seasonal structure to adapt to the new legislation while remaining faithful to its guiding principles. This capstone sets out to create a 21st Century Ivy League Model for men’s soccer. Using the proposed calendar included within the NCAA legislation as a starting point, this capstone worked to refine it to reflect the Founding Principles of Ivy League Athletics, namely that “academics and the personal growth of the students are of paramount importance” and that all student-athletes “shall be held to the same academic standards of the student body.” The capstone uses a thorough review of the literature surrounding the various challenges individuals encounter during their student-athlete experience, quantitative data from each of the current Ivy League men’s soccer program calendars, and a qualitative student athlete survey to drive the process of creating a theoretical two-semester model for the Ivy League’s consideration

    Cell Division: Righting the Check

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    SummaryStudies in fission and budding yeast have continuously led the way for analyzing pathways of cell division. Two elegant studies, one from each yeast species, are opening the gates to study one of the final steps of mitosis — silencing the spindle checkpoint

    The Shuttle Remote Manipulator System and Its Use in Orbital Operations

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    The Shuttle Remote Manipulator System (RMS) has been successfully flight tested during STS-2, 3 and 4 and declared operational. It has been flight qualified for light payloads with extrapolation by simulations for larger payloads. Testing of the RMS will continue with STS-7 and STS-11 and the RMS will see operational usage during the deployment of the Long Duration Exposure Facility (LDEF) and the Solar Max Mission (SMM) retrieval and repair on STS-13. This paper, includes a description of the RMS and the STS-2 to STS-4 Flight Tests. The RMS, in addition to handling payloads can perform other orbital operations such as inspection, construction and satellite servicing. This paper describes various end of arm tool concepts being developed by Spar, which could augment the basic RMS\u27s capability thereby increasing its versatility. A possible four phase program for implementation of a tool system is described which includes enhancement of the operators feel using force/moment sensing. In order to perform tasks such as construction and satellite servicing on the Orbiter in the future, the need for a Handling and Positioning Aid (HPA) is being considered. This device will essentially be a holding device or a work-bench vice on which the payload will be placed by the RMS and serviced either by an EVA astronaut or by the RMS or by a combination. A simple, costeffective design of the HPA derived entirely from existing space qualified elements of the RMS is presented in this paper
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