1,745 research outputs found
Faking like a woman? Towards an interpretative theorization of sexual pleasure.
This article explores the possibility of developing a feminist approach to gendered and sexual embodiment which is rooted in the pragmatist/interactionist tradition derived from G.H. Mead, but which in turn develops this perspective by inflecting it through more recent feminist thinking. In so doing we seek to rebalance some of the rather abstract work on gender and embodiment by focusing on an instance of 'heterosexual' everyday/night life - the production of the female orgasm. Through engaging with feminist and interactionist work, we develop an approach to embodied sexual pleasure that emphasizes the sociality of sexual practices and of reflexive sexual selves. We argue that sexual practices and experiences must be understood in social context, taking account of the situatedness of sex as well as wider socio-cultural processes the production of sexual desire and sexual pleasure (or their non-production) always entails interpretive, interactional processes
Tracking icebergs with time-lapse photography and sparse optical flow, LeConte Bay, Alaska, 2016–2017
We present a workflow to track icebergs in proglacial fjords using oblique time-lapse photos
and the Lucas-Kanade optical flow algorithm. We employ the workflow at LeConte Bay, Alaska, where we ran five time-lapse cameras between April 2016 and September 2017, capturing more than 400 000 photos at frame rates of 0.5–4.0 min−1. Hourly to daily average velocity fields in map coordinates illustrate dynamic currents in the bay, with dominant downfjord velocities (exceeding 0.5 m s−1 intermittently) and several eddies. Comparisons with simultaneous Acoustic Doppler Current Profiler (ADCP) measurements yield best agreement for the uppermost ADCP levels (∼ 12 m and above), in line with prevalent small icebergs that trace near-surface currents. Tracking results from multiple cameras compare favorably, although cameras with lower frame rates (0.5 min−1) tend to underestimate high flow speeds. Tests to determine requisite temporal and spatial image resolution confirm the importance of high image frame rates, while spatial resolution is of secondary importance. Application of our procedure to other fjords will be successful if iceberg concentrations are high enough and if the camera frame rates are sufficiently rapid (at least 1 min−1 for conditions similar to LeConte Bay).This work was funded by the U.S. National Science Foundation (OPP-1503910, OPP-1504288, OPP-1504521 and OPP-1504191).Ye
Spatiotemporal dispersion and wave envelopes with relativistic and pseudorelativistic characteristics
A generic nonparaxial model for pulse envelopes is presented. Classic Schro¨dinger-type descriptions of
wave propagation have their origins in slowly-varying envelopes combined with a Galilean boost to the
local time frame. By abandoning these two simplifications, a picture of pulse evolution emerges in which
frame-of-reference considerations and space-time transformations take center stage. A wide range of
effects, analogous to those in special relativity, then follows for both linear and nonlinear systems. Explicit
demonstration is presented through exact bright and dark soliton pulse solutions
Dispersive forces on bodies and atoms: a unified approach
A unified approach to the calculation of dispersive forces on ground-state
bodies and atoms is given. It is based on the ground-state Lorentz force
density acting on the charge and current densities attributed to the
polarization and magnetization in linearly, locally, and causally responding
media. The theory is applied to dielectric macro- and micro-objects, including
single atoms. Existing formulas valid for weakly polarizable matter are
generalized to allow also for strongly polarizable matter. In particular when
micro-objects can be regarded as single atoms, well-known formulas for the
Casimir-Polder force on atoms and the van der Waals interaction between atoms
are recovered. It is shown that the force acting on medium atoms--in contrast
to isolated atoms--is in general screened by the other medium atoms.Comment: 10 pages, 2 embedded figure
Wave envelopes with second-order spatiotemporal dispersion: II. Modulational instabilities and dark Kerr solitons
A simple scalar model for describing spatiotemporal dispersion of pulses, beyond the classic “slowly-varying envelopes + Galilean boost” approach, is studied. The governing equation has a cubic nonlinearity and we focus here mainly on contexts with normal group-velocity dispersion. A complete analysis of continuous waves is reported, including their dispersion relations and modulational instability characteristics. We also present a detailed derivation of exact analytical dark solitons, obtained by combining direct-integration methods with geometrical transformations. Classic results from conventional pulse theory are recovered as-ymptotically from the spatiotemporal formulation. Numerical simulations test new theoretical predictions for modulational instability, and examine the robustness of spatiotemporal dark solitons against perturbations to their local pulse shape
Why, what, and how? case study on law, risk, and decision making as necessary themes in built environment teaching
The paper considers (and defends) the necessity of including legal studies as a core part of built environment undergraduate and postgraduate curricula. The writer reflects upon his own experience as a lawyer working alongside and advising built environment professionals in complex land remediation and site safety management situations in the United Kingdom and explains how themes of liability, risk, and decision making can be integrated into a practical simulation in order to underpin more traditional lecture-based law teaching. Through reflection upon the writer's experiments with simulation-based teaching, the paper suggests some innovations that may better orientate law teaching to engage these themes and, thereby, enhance the relevance of law studies to the future needs of built environment professionals in practice.</p
Walking the walk: a phenomenological study of long distance walking
Evidence suggests that regular walking can elicit significant psychological benefits although little evidence exists concerning long distance walking. The purpose of this study was to provide detailed accounts of the experiences of long distance walkers. Phenomenological interviews were conducted with six long distance walkers. Data were transcribed verbatim before researchers independently analyzed the transcripts. Participants reported a cumulative effect with positive feelings increasing throughout the duration of the walk. Long distance walking elicited positive emotions, reduced the effects of life-stress, and promoted an increased sense of well-being and personal growth. Results are aligned to theories and concepts from positive psychology
Effect of the stellar spin history on the tidal evolution of close-in planets
We investigate how the evolution of the stellar spin rate affects, and is
affected by, planets in close orbits, via star-planet tidal interactions. To do
this, we used a standard equilibrium tidal model to compute the orbital
evolution of single planets orbiting both Sun-like stars and 0.1 M\odot
M-dwarfs. We tested two stellar spin evolution profiles, one with fast initial
rotation (P=1.2 day) and one with slow initial rotation (P=8 day). We tested
the effect of varying the stellar and planetary dissipation and the planet's
mass and initial orbital radius. Conclusions: Tidal evolution allows to
differentiate the early behaviors of extremely close-in planets orbiting either
a rapidly rotating star or a slowly rotating star. The early spin-up of the
star allows the close-in planets around fast rotators to survive the early
evolution. For planets around M-dwarfs, surviving the early evolution means
surviving on Gyr timescales whereas for Sun-like stars the spin-down brings
about late mergers of Jupiter planets. In light of this study, we can say that
differentiating between one spin evolution from another given the present
position of planets can be very tricky. Unless we can observe some markers of
former evolution it is nearly impossible to distinguish the two very different
spin profiles, let alone intermediate spin profiles. Though some conclusions
can still be drawn from statistical distributions of planets around fully
convective M-dwarfs. However, if the tidal evolution brings about a merger late
in its history it can also entail a noticeable acceleration of the star in late
ages, so that it is possible to have old stars that spin rapidly. This raises
the question of better constraining the age of stars
Bifurcation and stability for Nonlinear Schroedinger equations with double well potential in the semiclassical limit
We consider the stationary solutions for a class of Schroedinger equations
with a symmetric double-well potential and a nonlinear perturbation. Here, in
the semiclassical limit we prove that the reduction to a finite-mode
approximation give the stationary solutions, up to an exponentially small term,
and that symmetry-breaking bifurcation occurs at a given value for the strength
of the nonlinear term. The kind of bifurcation picture only depends on the
non-linearity power. We then discuss the stability/instability properties of
each branch of the stationary solutions. Finally, we consider an explicit
one-dimensional toy model where the double well potential is given by means of
a couple of attractive Dirac's delta pointwise interactions.Comment: 46 pages, 4 figure
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