488 research outputs found
Suspended liminality: Vacillating affects in cyberbullying/research
This paper develops a concept of liminal hotspots in the context of i) a secondary analysis of a cyberbullying case involving a group of school children from a Danish school, and ii) an altered auto-ethnography in which the authors âentangleâ their own experiences with the case analysis. These two sources are used to build an account of a liminal hotspot conceived as an occasion of troubled and suspended transformative transition in which a liminal phase is extended and remains unresolved. The altered auto-ethnography is used to explore the affectivity at play in liminal hotspots, and this liminal affectivity is characterised in terms of volatility, vacillation, suggestibility and paradox
From paradox to pattern shift: Conceptualising liminal hotspots and their affective dynamics
This article introduces the concept of liminal hotspots as a specifically psychosocial and sociopsychological type of wicked problem, best addressed in a process-theoretical framework. A liminal hotspot is defined as an occasion characterised by the experience of being trapped in the interstitial dimension between different forms-of-process. The paper has two main aims. First, to articulate a nexus of concepts associated with liminal hotspots that together provide general analytic purchase on a wide range of problems concerning âtroubledâ becoming. Second, to provide concrete illustrations through examples drawn from the health domain. In the conclusion, we briefly indicate the sense in which liminal hotspots are part of broader and deeper historical processes associated with changing modes for the management and navigation of liminality
Ab initio study of alanine polypeptide chains twisting
We have investigated the potential energy surfaces for alanine chains
consisting of three and six amino acids. For these molecules we have calculated
potential energy surfaces as a function of the Ramachandran angles Phi and Psi,
which are widely used for the characterization of the polypeptide chains. These
particular degrees of freedom are essential for the characterization of
proteins folding process. Calculations have been carried out within ab initio
theoretical framework based on the density functional theory and accounting for
all the electrons in the system. We have determined stable conformations and
calculated the energy barriers for transitions between them. Using a
thermodynamic approach, we have estimated the times of characteristic
transitions between these conformations. The results of our calculations have
been compared with those obtained by other theoretical methods and with the
available experimental data extracted from the Protein Data Base. This
comparison demonstrates a reasonable correspondence of the most prominent
minima on the calculated potential energy surfaces to the experimentally
measured angles Phi and Psi for alanine chains appearing in native proteins. We
have also investigated the influence of the secondary structure of polypeptide
chains on the formation of the potential energy landscape. This analysis has
been performed for the sheet and the helix conformations of chains of six amino
acids.Comment: 24 pages, 10 figure
High-fidelity, broadband stimulated-Brillouin-scattering-based slow light using fast noise modulation
We demonstrate a 5-GHz-broadband tunable slow-light device based on
stimulated Brillouin scattering in a standard highly-nonlinear optical fiber
pumped by a noise-current-modulated laser beam. The noise modulation waveform
uses an optimized pseudo-random distribution of the laser drive voltage to
obtain an optimal flat-topped gain profile, which minimizes the pulse
distortion and maximizes pulse delay for a given pump power. Eye-diagram and
signal-to-noise ratio (SNR) analysis show that this new broadband slow-light
technique significantly increases the fidelity of a delayed data sequence,
while maintaining the delay performance. A fractional delay of 0.81 with a SNR
of 5.2 is achieved at the pump power of 350 mW using a 2-km-long highly
nonlinear fiber with the fast noise-modulation method, demonstrating a 50%
increase in eye-opening and a 36% increase in SNR compared to a previous
slow-modulation method
Selective Intra-arterial Chemotherapy with Floxuridine as Second- or Third-Line Approach in Patients with Unresectable Colorectal Liver Metastases
Background: An outcome assessment was performed of patients with unresectable colorectal liver metastases (CRLM) treated in second or third line with floxuridine (FUDR)-based hepatic artery infusion (HAI). Methods: Twenty-three patients who were pretreated with systemic (immuno)chemotherapy received FUDR-HAI alone or combined with systemic chemotherapy. We reviewed patient charts and our prospective patient database for survival and associated risk factors. Results: Patients received FUDR-HAI for unresectable CRLM from January 2000 to September 2010. Twelve patients (52%) received concurrent systemic chemotherapy. Median overall survival (OS), progression-free survival (PFS), and hepatic PFS were 15.6months (range, 2.5-55.7months), 3.9months (range, 0.7-55.7months), and 5.5months (range, 1.6-55.7months), respectively. The liver resection rate after HAI was 35%. PFS was better in patients undergoing secondary resection than in patients without resection (hazard ratio [HR] 0.21; 95% confidence interval [95% CI] 0.07-0.66; P=0.0034), while OS showed a trend toward improvement (HR 0.4; 95% CI 0.13-1.2; P=0.09). No differences were observed in OS (P=0.69) or PFS (P=0.086) in patients who received FUDR-HAI alone compared with patients treated with combined regional and systemic chemotherapy. No statistically significant differences were seen in patients previously treated with one chemotherapy line compared with patients treated with two lines. Presence of extrahepatic disease was a negative risk factor for PFS (liver-only disease: HR 0.03; 95% CI 0.0032-0.28; P<0.0001). Toxicities were manageable with dose modifications and supportive measures. Conclusions: FUDR-HAI improves PFS and results in a trend toward improved OS in selected patients able to undergo liver resection after tumor is downsize
Controllable ultra-broadband slow light in a warm Rubidium vapor
We study ultra-broadband slow light in a warm Rubidium vapor cell. By working
between the D1 and D2 transitions, we find a several-nm window centered at
788.4 nm in which the group index is highly uniform and the absorption is small
(<1%). We demonstrate that we can control the group delay by varying the
temperature of the cell, and observe a tunable fractional delay of 18 for
pulses as short as 250 fs (6.9 nm bandwidth) with a fractional broadening of
only 0.65 and a power leakage of 55%. We find that a simple theoretical model
is in excellent agreement with the experimental results. Using this model, we
discuss the impact of the pulse's spectral characteristics on the distortion it
incurs during propagation through the vapor.Comment: The first two authors contributed equally to this wor
Surface Rupture and Slip Distribution of the Denali and Totschunda Faults
The 3 November 2002 Denali fault, Alaska, earthquake resulted in
341 km of surface rupture on the Susitna Glacier, Denali, and Totschunda faults. The
rupture proceeded from west to east and began with a 48-km-long break on the
previously unknown Susitna Glacier thrust fault. Slip on this thrust averaged about
4 m (Crone et al., 2004). Next came the principal surface break, along 226 km of
the Denali fault, with average right-lateral offsets of 4.5â5.1 m and a maximum offset
of 8.8 m near its eastern end. The Denali fault trace is commonly left stepping and
north side up. About 99 km of the fault ruptured through glacier ice, where the trace
orientation was commonly influenced by local ice fabric. Finally, slip transferred
southeastward onto the Totschunda fault and continued for another 66 km where
dextral offsets average 1.6â1.8 m. The transition from the Denali fault to the Totschunda
fault occurs over a complex 25-km-long transfer zone of right-slip and
normal fault traces. Three methods of calculating average surface slip all yield a
moment magnitude of Mw 7.8, in very good agreement with the seismologically
determined magnitude of M 7.9. A comparison of strong-motion inversions for moment
release with our slip distribution shows they have a similar pattern. The locations
of the two largest pulses of moment release correlate with the locations of
increasing steps in the average values of observed slip. This suggests that slipdistribution
data can be used to infer moment release along other active fault traces.PublishedS23âS52reserve
Polarization instabilities in a two-photon laser
We describe the operating characteristics of a new type of quantum oscillator
that is based on a two-photon stimulated emission process. This two-photon
laser consists of spin-polarized and laser-driven K atoms placed in a
high-finesse transverse-mode-degenerate optical resonator, and produces a beam
with a power of 0.2 W at a wavelength of 770 nm. We observe
complex dynamical instabilities of the state of polarization of the two-photon
laser, which are made possible by the atomic Zeeman degeneracy. We conjecture
that the laser could emit polarization-entangled twin beams if this degeneracy
is lifted.Comment: Accepted by Physical Review Letters. REVTeX 4 pages, 4 EPS figure
Sheâs so vain? A Q Study of Selfies and the curation of an online self.
Selfie posting is now a well-established practice, particularly for young women. However, it is nevertheless much maligned in popular discourses. As a counterpoint to digital narcissism, selfie posting is also constituted as relational. This Q methodological study explored how young women make sense of selfie practices. Twenty-seven young women aged 18-23 sorted a set of statements about selfies into a quasi-normal grid. These sorts were factor analysed to identify shared patterns. Four factors were identified which were subsequently analysed qualitatively, producing a narrative for each. These included, (1) âPresentingâŠMe!â (2) âI am what I amâ, (3) âSharing is caringâ and (4) âThe In-crowd â beautiful and popularâ. The complexity of identity curation evidenced in this study highlights the importance of moving beyond both polarised characterisations and the pathologisation of young women selfie takers in order to explicate the interplay between normative femininities and the digital self
- âŠ