268 research outputs found

    One at a time, live tracking of NGF axonal transport using quantum dots

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    Retrograde axonal transport of nerve growth factor (NGF) signals is critical for the survival, differentiation, and maintenance of peripheral sympathetic and sensory neurons and basal forebrain cholinergic neurons. However, the mechanisms by which the NGF signal is propagated from the axon terminal to the cell body are yet to be fully elucidated. To gain insight into the mechanisms, we used quantum dot-labeled NGF (QD-NGF) to track the movement of NGF in real time in compartmentalized culture of rat dorsal root ganglion (DRG) neurons. Our studies showed that active transport of NGF within the axons was characterized by rapid, unidirectional movements interrupted by frequent pauses. Almost all movements were retrograde, but short-distance anterograde movements were occasionally observed. Surprisingly, quantitative analysis at the single molecule level demonstrated that the majority of NGF-containing endosomes contained only a single NGF dimer. Electron microscopic analysis of axonal vesicles carrying QD-NGF confirmed this finding. The majority of QD-NGF was found to localize in vesicles 50–150 nm in diameter with a single lumen and no visible intralumenal membranous components. Our findings point to the possibility that a single NGF dimer is sufficient to sustain signaling during retrograde axonal transport to the cell body

    Experimental and theoretical study of the Gouy phase anomaly of light in the focus of microlenses

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    We report on the Gouy phase anomaly of light in the focus of cylindrical and spherical microlenses. The prime subject of our study concerns a discussion of how the very small size of microlenses affects the phase properties of light in their foci. We put emphasis on determining the amount of the Gouy phase shift for line and point foci within the limited axial space. Contrary to macroscopic lenses, the optical properties of microlenses are strongly governed by the effect of diffraction when their size tends to be comparable to the operation wavelength. In our study, we clearly show how such diffraction features affect the axial phase shift. For instance, phase singularities, which occur at discrete points on the optical axis where the total intensity vanishes for spherical microlenses, cause an additional axial phase shift when compared to the cylindrical microlens where those axial phase singularities are absent. The rotational symmetry of the Fresnel zones is the origin of such a difference between point and line foci

    The Lantern Vol. 52, No. 1, Fall 1985

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    • Nudes • Orion • Fragments of an Epic • Sunrise • The Planting Season • Nursing Home • Hope Chest • Childhood Swing • Relationships • Elroy, Leopold, and Max • Urban Dragon • The Farmer\u27s Wife • A Ballad of Two Lovers • Betrayal • Choices • Letting Go • Emergence of a Butterfly • Poem for Every Man • Friction • Genesis • All\u27s Well • The Willow Tree • White Wasteland • Moe\u27s Happy Christmas • Rare Bird • Carnivalhttps://digitalcommons.ursinus.edu/lantern/1127/thumbnail.jp

    The Lantern Vol. 51, No. 2, Spring 1985

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    • Electric Pink • Derby Day • Conversation • Seasons of Sonnets • Long After Killing Us • Haunting Memory • Sacrifice • Is This Positive Enough? • My Teddy Bear • A Gentleman of Ten • Hartman Center • Yesterday\u27s Child • Mors Pueris • Momentary Reflections • Children Sleeping • There\u27s No Place Like Home • I Set My Pleasures Adrift • The Beer Can • Fragments of an Epic • Actaeon • She Sleeps • Chicago • Death Light • Tea With Louise • Balance • The Rivers • Chapel • The Hour of Prayer • Une Fille / Une Femme • A One-Way Mirror • Nonconformity • Cada Noche, Lloro • Reflections on an Empty House Down the Street • Evening Melancholy • Abandoned Road • Big Boy • Baby Brothers • Metro Oscuro • Chuchoterhttps://digitalcommons.ursinus.edu/lantern/1126/thumbnail.jp

    Applications of SOI-based optical MEMS

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    After microelectromechanical systems (MEMS) devices have been well established, components of higher complexity are now developed. Particularly, the combination with optical components has been very successful and have led to optical MEMS. The technology of choice for us is the silicon-on-insulator (SOI) technology, which has also been successfully used by other groups. The applications presented here give an overview over what is possible with this technology. In particular, we demonstrate four completely different devices: a) a 2 × 2 optical cross connector (OXC) with an insertion loss of about 0.4 dB at a switching time of 500 μs and its extension to a 4 × 4 OXC, b) a variable optical attenuators (VOA), which has an attenuation range of more than 50 dB, c) a Fourier transform spectrometer (FTS) with a spectral resolution of 6 nm in the visible, and d) an accelerometer with optical readout that achieves a linear dynamic range of 40 dB over ±6 g. Except for the FTS, all the applications utilized optical fibers, which are held and self-aligned within the MEMS component by U-grooves and small leaf springs. All devices show high reliability and a very low power consumption

    The Lantern Vol. 50, No. 2, Spring 1984

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    • The Storm • Je ne sais pas • The Ghetious Blastious • An Empty Cradle • The Playing Hands • Battle Hymn • A Limerick • Parting Thoughts • The River • Miss You • De la Tristeza • Two So Special • Time of the Unicorn • The Absence • Thru The Breeze • Is the World Really a Round Ball? • Brother • To Michael • Gravity • Refuge • Der Witwer • Plastic Flowers Never Die • Book on the Shelfhttps://digitalcommons.ursinus.edu/lantern/1124/thumbnail.jp

    Exploring institutional reform of Korean civil service pension: advocacy coalition framework, policy knowledge and social innovation

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    Abstract This paper examines what factors are associated with the 2015 pension reform of Korean civil servant as social innovation. We explore what lessons we can learn from the pension reform in terms of the Advocacy Coalition Framework (ACF) model. The ACF model allows us to identify how the substantial reform is, relying on policy knowledge and entrepreneurs, possible in terms of political and social consensus. It also clearly demonstrates the possibility of systematic pension reform at an appropriate level through social learning and policy learning. Through the ACF model, we review how South Koreas civil servant pension reform act occurred at the end of May 2015. The temporal scope covers from 2009 latest reform, and the 2014s President administrative policy speech that had strongly been showed her will to reform the pension issue to the end of May 2015 when the reform bill enacted. We investigate each advocacy coalition in order to elucidate the actors that constitute the two coalition groups and to scrutinize whether a policy broker had existed in the process. We also attempt to find the relatively stable parameters and external events that affected the reform and also the belief system that shared by two advocacy coalition group. The result clearly shows that the two coalition groups shared their normative beliefs ultimately, for example, the need to change the current civil servants pension system, but, the gap in the numerical change in the policy core belief and secondary belief between the two actors had seemed to be excessively large and uncompromising. A policy broker who can coordinate the interests and interests of stakeholder groups over the government pension reform proposal was desperately needed. Negotiation and leadership of the policy entrepreneurs led to a settlement of the government pension reform proposal at the end of May 2015. Their entrepreneurial activities led to an appropriate level of social consensus on the sustainable reform of pension system through policy knowledge and learning. Further research is required to explore how models of socially innovative forms of governance are created in various pension reforms across various countries. It is also required to examine how policy entrepreneurs use policy knowledge and information for a successful institutional reform through social innovation across various countries

    Biosemiotics, politics and Th.A. Sebeok’s move from linguistics to semiotics

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    This paper will focus on the political implications for the language sciences of Sebeok’s move from linguistics to a global semiotic perspective, a move that ultimately resulted in biosemiotics. The paper will seek to make more explicit the political bearing of a biosemiotic perspective in the language sciences and the human sciences in general. In particular, it will discuss the definition of language inherent in Sebeok’s project and the fundamental re-drawing of the grounds of linguistic debate heralded by Sebeok’s embrace of the concept of modelling. Thus far, the political co-ordinates of the biosemiotic project have not really been made explicit. This paper will therefore seek to outline 1. how biosemiotics enables us to reconfigure our understanding of the role of language in culture; 2. how exaptation is central to the evolution of language and communication, rather than adaptation; 3. how communication is the key issue in biosphere, rather than language, not just because communication includes language but because the language sciences often refer to language as if it were mere “chatter”, “tropes” and “figures of speech”; 4. how biosemiotics, despite its seeming “neutrality” arising from its transdisciplinarity, is thoroughly political; 5. how the failure to see the implications of the move from linguistics to semiotics arises from the fact that biosemiotics is devoid of old style politics, which is based on representation (devoid of experience) and “construction of [everything] in discourse” (which is grounded in linguistics, not communication study). In contrast to the post-“linguistic turn” idea that the world is “constructed in discourse”, we will argue that biosemiotics entails a reconfiguration of the polis and, in particular, offers the chance to completely reconceptualise ideology
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