2,104 research outputs found

    Measurement of heavy-hole spin dephasing in (InGa)As quantum dots

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    We measure the spin dephasing of holes localized in self-assembled (InGa)As quantum dots by spin noise spectroscopy. The localized holes show a distinct hyperfine interaction with the nuclear spin bath despite the p-type symmetry of the valence band states. The experiments reveal a short spin relaxation time {\tau}_{fast}^{hh} of 27 ns and a second, long spin relaxation time {\tau}_{slow}^{hh} which exceeds the latter by more than one order of magnitude. The two times are attributed to heavy hole spins aligned perpendicular and parallel to the stochastic nuclear magnetic field. Intensity dependent measurements and numerical simulations reveal that the long relaxation time is still obscured by light absorption, despite low laser intensity and large detuning. Off-resonant light absorption causes a suppression of the spin noise signal due to the creation of a second hole entailing a vanishing hole spin polarization.Comment: accepted to be published in AP

    Theory for Spin-Polarized Oscillations in Nonlinear Magneto-Optics due to Quantum Well States

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    Using an electronic tight-binding theory we calculate the nonlinear magneto-optical response from an x-Cu/1Fe/Cu(001) film as a function of frequency and Cu overlayer thickness (x=3 ... 25). We find very strong spin-polarized quantum well oscillations in the nonlinear magneto-optical Kerr effect (NOLIMOKE). These are enhanced by the large density of Fe dd states close to the Fermi level acting as intermediate states for frequency doubling. In good agreement with experiment we find two oscillation periods of 6-7 and 11 monolayers the latter being more pronounced.Comment: 12 pages, Revtex, 3 postscript figure

    Sensoria: An exploratory interdisciplinary framework for researching multimodal & sensory experiences

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    This paper describes the development and salience of an original and innovative interdisciplinary approach, Sensoria, that combines methods and techniques from social science and performance to address the methodological challenges of researching sensory/multimodal experiences. It sets out the core components and methodological principles that underpin the approach and uses an illustrative example to show how it can facilitate research on hard to access sensorial experiences, to access, understand and analyse people’s experiences and perspectives of touch, a highly tacit sensory mode. The paper discusses the methodological contribution and challenges of this approach to sensory research for social science and artistic practice and ‘more-than-representational’ research more generally. It concludes by making a case for more critical research spaces at the intersection of these disciplines to foster multi-dimensional research dialogues and to advance the exploration and understanding of the relationship between the sensory, social and the digital

    Shifting identities : the musician as theatrical perfomer

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    The artistic PhD research "Shifting Identities" investigates the musicians' professional identity and how this identity might shift when musicians start acting as theatrical performers. In most of the theatrical situations where musicians "perform", their profession is extended by additional tasks such as walking on stage or reciting text. As an alternative strategy to extension, this research introduces and focuses on reduction, which means the abstracting away of specific qualities or abilities of the musician's profession. The audience watches musicians not doing certain things that usually belong to their profession. Both the expansive and the reductive approaches are concepts of working theatrically with musicians. They are different, perhaps even contradictory strategies, but both bear the ability to enrich the musician's professional identity with a more theatrical appearance. In order to build an understanding of what is extended or reduced when the identity shifts from a musician to a theatrical (musician-)performer a dynamic model is developed which builds strongly on what musicians actually do, a model that categorises the musician's professional activities into internal, external and contextual elements.Stichting de Zaaier, Lectoraat Theatrale Maakprocessen, HKU School of TheatreResearch in and through artistic practic

    A Concept For The Development Of A Maturity Model For The Holistic Assessment Of Lean, Digital, and Sustainable Production Systems

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    Manufacturing companies today face a volatile environment with a variety of challenges. Particularly, external factors such as the climate change, the digitalization, the material scarcity, or the shortage of skilled workers can be noted. At the same time, these factors are forcing companies to take measures to remain competitive and ensure their production system's future viability. In this context, established paradigms such as Lean Production and Industry 4.0 promise optimization potentials in terms of efficiency, quality, and costs. A new paradigm has gained importance with the emergence of the topic of sustainability, which aims to improve companies' use of resources and the recyclability of their products. However, there is no transparent model that enables companies to assess the status quo of their production system regarding these three paradigms, considering the interdependencies between the paradigms, and at the same time showing the implementation potential of methods or technologies within these paradigms. To support companies in rationalizing, digitalizing, and making their production processes more sustainable, this scientific paper presents a three-stage concept for a holistic maturity model. By providing transparency about the status quo of production systems in terms of Lean Production, digitalization, and sustainability, the model contributes to ensuring the future viability of such production systems in this highly competitive environment and under the political, social, and regulatory challenges

    Impact of weekday surgery on application of enhanced recovery pathway: a retrospective cohort study.

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    To compare the enhanced recovery after surgery (ERAS) protocol compliance and clinical outcomes depending on the weekday of surgery. Cohort of consecutive non-selected patients undergoing elective colorectal surgery from January 2012 to March 2015. This retrospective analysis of our prospective database compared patients operated early in the week (Monday and Tuesday) with patients operated in the second half (late: Thursday, Friday). Compliance with the ERAS protocol, functional recovery, complications and length of stay. Demographic and surgical details were similar between the early (n=352) and late groups (n=204). Overall compliance with the ERAS protocol was 78% vs 76% for the early and late groups, respectively (p=0.009). Significant differences were notably prolonged urinary drainage and intravenous fluid infusion in the late group. Complication rates and length of stay, however, were not different between surgery on Monday or Tuesday and surgery on Thursday or Friday. Application of the ERAS protocol showed only minor differences for patients operated on early or late during the week, and clinical outcomes were similar. A fully implemented ERAS programme appears to work also over the weekend

    Correlation of postoperative fluid balance and weight and their impact on outcomes.

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    Normovolemia after major surgery is critical to avoid complications. The aim of the present study was to analyze correlation between fluid balance, weight gain, and postoperative outcomes. All consecutive patients undergoing elective or emergency major abdominal surgery needing intermediate care unit (IMC) admission from September 2017 to January 2018 were included. Postoperative fluid balances and daily weight changes were calculated for postoperative days (PODs) 0-3. Risk factors for postoperative complications (30-day Clavien) and prolonged length of IMC and hospital stay were identified through uni- and multinominal logistic regression. One hundred eleven patients were included, of which 55% stayed in IMC beyond POD 1. Overall, 67% experienced any complication, while 30% presented a major complication (Clavien ≥ III). For the entire cohort, median cumulative fluid balance at the end of PODs 0-1-2-3 was 1850 (IQR 1020-2540) mL, 2890 (IQR 1610-4000) mL, 3890 (IQR 2570-5380) mL, and 4000 (IQR 1890-5760) mL respectively, and median weight gain was 2.2 (IQR 0.3-4.3) kg, 3 (1.5-4.7) kg, and 3.9 (2.5-5.4) kg, respectively. Fluid balance and weight course showed no significant correlation (r = 0.214, p = 0.19). Extent of surgery, analyzed through Δ albumin and duration of surgery, significantly correlated with POD 2 fluid balances (p = 0.04, p = 0.006, respectively), as did POD 3 weight gain (p = 0.042). Prolonged IMC stay of ≥ 3 days was related to weight gain ≥ 3 kg at POD 2 (OR 2.8, 95% CI 1.01-8.9, p = 0.049). Fluid balance and weight course showed only modest correlation. POD 2 weight may represent an easy and pragmatic tool to optimize fluid management and help to prevent fluid-related postoperative complications
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