211 research outputs found

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

    Get PDF
    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. 51, No. 2, Spring 1985

    Get PDF
    • 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

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

    Get PDF
    • 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. 50, No. 2, Spring 1984

    Get PDF
    • 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

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

    Get PDF
    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

    The role of place branding and image in the development of sectoral clusters: the case of Dubai

    Get PDF
    This paper contextualizes how place branding and image influence the development of Dubai’s key sectoral clusters, including the key determinants of growth and success under the impression of Porter’s cluster theory. The approach is exploratory and of a qualitative inductive nature. Data was collected through conducting 21 semi-structured interviews with Dubai’s marketing/communication managers and stakeholders. Findings suggest that Dubai’s traditional clusters, namely, trading, tourism and logistics that have strong place branding and image show strong signs of success owing to Dubai’s geographical location (i.e., physical conditions). Among the new clusters, the financial sector is also benefitting from place branding. The results suggest that the success of traditional clusters have a positive spill over effect on the new clusters, in particular on construction and real estate. For policy makers it is worth to note that the recent success of the financial services cluster in Dubai will have positive impact on both, the traditional as well new clusters. The marketing and brand communication managers must consider the correlation and interplay of strength of activities amongst trading, tourism and logistics clusters and its implication while undertaking place branding for clients in their sector

    Climate stories: Why do climate scientists and sceptical voices participate in the climate debate?

    Get PDF
    Public perceptions of the climate debate predominantly frame the key actors as climate scientists versus sceptical voices; however, it is unclear why climate scientists and sceptical voices choose to participate in this antagonistic and polarised public battle. A narrative interview approach is used to better understand the underlying rationales behind 22 climate scientists’ and sceptical voices’ engagement in the climate debate, potential commonalities, as well as each actor’s ability to be critically self-reflexive. Several overlapping rationales are identified including a sense of duty to publicly engage, agreement that complete certainty about the complex assemblage of climate change is unattainable and that political factors are central to the climate debate. We argue that a focus on potential overlaps in perceptions and rationales as well as the ability to be critically self-reflexive may encourage constructive discussion among actors previously engaged in purposefully antagonistic exchange on climate change

    The Achievement of a Decentralized Water Management Through Stakeholder Participation: An Example from the Drôme River Catchment Area in France (1981–2008)

    Get PDF
    International audienceDifferent water Acts (e.g., the European Water Framework Directive) and stakeholders involved in aquatic affairs have promoted integrated river basin management (IRBM) over recent decades. However, few studies have provided feedback on these policies. The aim of the current article is to fill this gap by exploring how local newspapers reflect the implementation of a broad public participation within a catchment of France known for its innovation with regard to this domain. The media coverage of a water management strategy in the Drôme watershed from 1981 to 2008 was investigated using a content analysis and a geographic information system (GIS). We sought to determine what public participation and decentralized decision-making can be in practice. The results showed that this policy was integrated because of its social perspective, the high number of involved stakeholders, the willingness to handle water issues, and the local scale suitable for participation. We emphasized the prominence of the watershed scale guaranteed by the local water authority. This area was also characterized by compromise, arrangements, and power dynamics on a fine scale. We examined the most politically engaged writings regarding water management, which topics each group emphasized, and how the groups agreed and disagreed on issues based on their values and context. The temporal pattern of participation implementation was progressive but worked by fits and starts

    Dopaminergic modulation of appetitive trace conditioning: the role of D1 receptors in medial prefrontal cortex

    Get PDF
    Rationale: Trace conditioning may provide a behavioural model suitable to examine the maintenance of ‘on line’ information and its underlying neural substrates. Objectives: Experiment la was run to establish trace conditioning in a shortened procedure which would be suitable to test the effects of dopamine (DA) D1 receptor agents administered by microinjection directly into the brain. Experiment lb examined the effects of the DA D1 agonist SKF81297 and the DA D1 antagonist SCH23390 following systemic administration in pre-trained animals. Experiment 2 went on to test the effects of systemically administered SKF81297 on the acquisition of trace conditioning. In experiment 3, SKF81297 was administered directly in prelimbic (PL) and infralimbic (IL) sub-regions of medial prefrontal cortex (mPFC) to compare the role of different mPFC sub-regions. Results: Whilst treatment with SCH23390 impaired motor responding and/or motivation, SKF81297 had relatively little effect in the pre-trained animals tested in experiment 1b. However, systemic SKF81297 depressed the acquisition function at the 2-s trace interval in experiment 2. Similarly, in experiment 3, SKF81297 (0.1 μg in 1.0 μl) microinjected into either PL or IL mPFC impaired appetitive conditioning at the 2-s trace interval. Conclusions: Impaired trace conditioning under SKF81297 is likely to be mediated in part (but not exclusively) within the IL and PL mPFC sub-regions. The finding that trace conditioning was impaired rather than enhanced under SKF81297 provides further evidence for the inverse U-function which has been suggested to be characteristic of mPFC DA function
    corecore