The Role of Multidimensional Library Neutrality in Advancing Social Justice: Adapting Theoretical Foundations from Political Science and Urban Planning

There is an ongoing, polarizing debate in the library profession and scholarship regarding the perceived incompatibility between library neutrality (embedded in the profession through the American Library Association’s Library Bill of Rights), and social justice goals. This article asserts that the growing antipathy on the part of some library practitioners and scholars towards neutrality and intellectual freedom is owed at least in part to the profession and scholarship having never articulated an adequate definition of what is meant by neutrality. As a result, the profession lacks a theoretical framework situating the library and library staff as political actors within a multicultural and largely urban society. We argue that such a framework may be drawn from the literatures of political science and urban planning. By positioning libraries and library workers within the context of liberal-democratic institutions – as is the case for urban planners in their theoretical literature – LIS theory can find more durable foundations for its core values. Stressing planning’s commitments to the participation of multiple publics, to dialogue, mediation and to consensus-building through liberal institutions, we develop a multidimensional understanding of neutrality premised on values, stakeholders, processes and goals which we then apply to these planning modes. Finally, we propose a model of “Communicative Librarianship” as best exemplifying these four dimensions of neutrality and their attendant democratic commitments

Supercontinuum light

International audienceWhen coupled into an optical waveguide, the familiar narrowband radiation from a laser can become spectrally broadened into the ultimate white light

On Hokusai's great wave off Kanagawa: Localization, linearity and a rogue wave in sub-antarctic waters

International audienceThe Hokusai woodcut entitled The great wave off Kanagawa has been interpreted as an unusually large storm wave, likely to be classed as a rogue wave, and possibly generated from nonlinear wave dynamics (J. H. E. Cartwright and H. Nakamura, Notes Rec. R. Soc. 63, 119-135 (2009)). In this paper, we present a complementary discussion of this hypothesis, discussing in particular how linear and nonlinear mechanisms can both contribute to the emergence of rogue wave events. By making reference to the Great wave's simultaneous transverse and longitudinal localization, we show that the purely linear mechanism of directional focusing also predicts characteristics consistent with those of the Great wave. In addition, we discuss the properties of a particular rogue wave photographed on the open ocean in sub-Antarctic waters, which shows two-dimensional localization and breaking dynamics remarkably similar to Hokusai's depiction in the woodcut

Extreme wave runup on a vertical cliff

International audienceWave impact and runup onto vertical obstacles are among the most important phenomena which must be taken into account in the design of coastal structures. From linear wave theory, we know that the wave amplitude on a vertical wall is twice the incident wave amplitude with weakly nonlinear theories bringing small corrections to this result. In this present study, however, we show that certain simple wave groups may produce much higher runups than previously predicted, with particular incident wave frequencies resulting in runup heights exceeding the initial wave amplitude by a factor of 5, suggesting that the notion of the design wave used in coastal structure design may need to be revisited. The results presented in this study can be considered as a note of caution for practitioners, on one side, and as a challenging novel material for theoreticians who work in the field of extreme wave-coastal structure interaction

Applications of femtosecond Bessel beams to laser ablation

International audienceNondiffracting Bessel beams have been recently applied to single shot ultrafast laser processing of high aspect ratio nanochannels.We review the principles and benefits of nondiffracting Bessel beams for material processing, and we compare experimental results with numerical simulations. We show how the stationarity of nonlinear propagation of ultrafast laser pulses allows high aspect ratio material processing

Femtosecond laser fabrication of micro and nano-disks in single layer graphene using vortex Bessel beams

International audienceWe report the fabrication of micro and nano-disks in single layer chemical vapor deposition graphene on glass substrate using femtosecond laser ablation with vortex Bessel beams. The fabricated graphene disks with diameters ranging from 650 nm to 4 μm were characterized by spatially resolved micro-Raman spectroscopy. The variation of ablation threshold was investigated as a function of the number of pulses showing an incubation effect. A very high degree of size control of the fabricated graphene disks is enabled using a sequence of femtosecond pulses with different vortex orders

Direct machining of curved trenches in silicon with femtosecond accelerating beams

International audienceControl of the longitudinal profile of ablated structures during laser processing is a key technological requirement. We report here on the direct machining of trenches in silicon with circular profiles using femtosecond accelerating beams. We describe the ablation process based on an intensity threshold model, and show how the depth of the trenches can be predicted in the framework of a caustic description of the beam

Effect of 2\u27,3\u27-Didehydro-3\u27-Deoxythymidine in an In Vitro Hollow-Fiber Pharmacodynamic Model System Correlates with Results of Dose-Ranging Clinical Studies

We sought to validate an in vitro system which could predict the minimal effect dose of antiretroviral agents. Mixtures of uninfected CEM cells and CEM cells chronically infected with human immunodeficiency virus (HIV) type 1 MN were exposed to 2\u27,3\u27-didehydro-3\u27-deoxythymidine (D4T) in vitro in a hollow-fiber model which simulates the plasma concentration-time profile of D4T in patients. Drug concentration was adjusted to simulate continuous intravenous infusion, or an intravenous bolus administered twice daily. The effect of the dosing regimen was measured with viral infectivity, p24 antigen, and reverse transcriptase or PCR for unintegrated HIV DNA. Dose deescalation studies on a twice-daily dosing schedule predicted a minimum effect dose of 0.5 mg/kg of body weight per day which correlated with the results of a clinical trial. Antiviral effect was demonstrated to be independent of schedule for every 12-h dosing versus continuous infusion. Finally, at or near the minimal effect dose, efficacy appeared to depend on the viral load. The ability of this in vitro pharmacodynamic model to assess the response of HIV-infected cells to different doses and schedules of antiviral agents may be useful in the design of optimal dosing regimens for clinical trials but requires validation with other types of antiretroviral agents

Spherical light, arbitrary nonparaxial accelerating beams and femtosecond laser micromachining of curved profiles

International audienceWe review our recent results applying caustics wave theory to the generation of arbitrary curved accelerating beams and their use in the field of femtosecond laser materials processing. We report experimental realization of highly nonparaxial accelerating beams with circular, parabolic and quartic trajectories that extend over more than 95 degrees of arc as well as spherical optical fields. We also report femtosecond laser curved edge profiling

Micromachining along a curve: Femtosecond laser micromachining of curved profiles in diamond and silicon using accelerating beams

International audienceWe report femtosecond laser micromachining of micron-size curved structures using tailored accelerating beams. We report surface curvatures as small as 70 μm in both diamond and silicon, which demonstrates the wide applicability of the technique to materials that are optically transparent or opaque at the pump laser wavelength. We also report the machining of curved trenches in silicon. Our results are consistent with an ablation-threshold model based on calculated local beam intensity, and we also observe asymmetric debris deposition which is interpreted in terms of the optical properties of the incident accelerating beam