Spectrum of the Nuclear Environment for GaAs Spin Qubits

Using a singlet-triplet spin qubit as a sensitive spectrometer of the GaAs nuclear spin bath, we demonstrate that the spectrum of Overhauser noise agrees with a classical spin diffusion model over six orders of magnitude in frequency, from 1 mHz to 1 kHz, is flat below 10 mHz, and falls as $1/f^2$ for frequency $f \! \gtrsim \! 1$ Hz. Increasing the applied magnetic field from 0.1 T to 0.75 T suppresses electron-mediated spin diffusion, which decreases spectral content in the $1/f^2$ region and lowers the saturation frequency, each by an order of magnitude, consistent with a numerical model. Spectral content at megahertz frequencies is accessed using dynamical decoupling, which shows a crossover from the few-pulse regime ($\lesssim \! 16$ $\pi$-pulses), where transverse Overhauser fluctuations dominate dephasing, to the many-pulse regime ($\gtrsim \! 32$ $\pi$-pulses), where longitudinal Overhauser fluctuations with a $1/f$ spectrum dominate.Comment: 6 pages, 4 figures, 8 pages of supplementary material, 5 supplementary figure

Atomic Oxygen Treatment as a Method of Recovering Smoke Damaged Paintings

Smoke damage, as a result of a fire, can be difficult to remove from some types of painting media without causing swelling, leaching or pigment movement or removal. A non-contact technique has been developed which can remove soot from the surface of a painting by use of a gently flowing gas containing atomic oxygen. The atomic oxygen chemically reacts with the soot on the surface creating gasses such as carbon monoxide and carbon dioxide which can be removed through the use of an exhaust system. The reaction is limited to the surface so that the process can be timed to stop when the paint layer is reached. Atomic oxygen is a primary component of the low Earth orbital environment, but can be generated on Earth through various methods. This paper will discuss the results of atomic oxygen treatment of soot exposed acrylic gesso, ink on paper, and a varnished oil painting. Reflectance measurements were used to characterize the surfaces before and after treatment

Microfluidic active loading of single cells enables analysis of complex clinical specimens

A fundamental trade-off between flow rate and measurement precision limits performance of many single-cell detection strategies, especially for applications that require biophysical measurements from living cells within complex and low-input samples. To address this, we introduce ‘active loading’, an automated, optically-triggered fluidic system that improves measurement throughput and robustness by controlling entry of individual cells into a measurement channel. We apply active loading to samples over a range of concentrations (1–1000 particles μL[superscript −1]), demonstrate that measurement time can be decreased by up to 20-fold, and show theoretically that performance of some types of existing single-cell microfluidic devices can be improved by implementing active loading. Finally, we demonstrate how active loading improves clinical feasibility for acute, single-cell drug sensitivity measurements by deploying it to a preclinical setting where we assess patient samples from normal brain, primary and metastatic brain cancers containing a complex, difficult-to-measure mixture of confounding biological debris.National Cancer Institute (U.S.) (R01 CA170592)National Cancer Institute (U.S.) (R33 CA191143)National Cancer Institute (U.S.) (Cancer Center Support (Core) Grant P30-CA14051)Bridge Projec

Microfluidic active loading of single cells enables analysis of complex clinical specimens

A fundamental trade-off between flow rate and measurement precision limits performance of many single-cell detection strategies, especially for applications that require biophysical measurements from living cells within complex and low-input samples. To address this, we introduce ‘active loading’, an automated, optically-triggered fluidic system that improves measurement throughput and robustness by controlling entry of individual cells into a measurement channel. We apply active loading to samples over a range of concentrations (1–1000 particles μL[superscript −1]), demonstrate that measurement time can be decreased by up to 20-fold, and show theoretically that performance of some types of existing single-cell microfluidic devices can be improved by implementing active loading. Finally, we demonstrate how active loading improves clinical feasibility for acute, single-cell drug sensitivity measurements by deploying it to a preclinical setting where we assess patient samples from normal brain, primary and metastatic brain cancers containing a complex, difficult-to-measure mixture of confounding biological debris.National Cancer Institute (U.S.) (R01 CA170592)National Cancer Institute (U.S.) (R33 CA191143)National Cancer Institute (U.S.) (Cancer Center Support (Core) Grant P30-CA14051)Bridge Projec

Dreaming and insight

This paper addresses claims that dreams can be a source of personal insight. Whereas there has been anecdotal backing for such claims, there is now tangential support from findings of the facilitative effect of sleep on cognitive insight, and of REM sleep in particular on emotional memory consolidation. Furthermore, the presence in dreams of metaphorical representations of waking life indicates the possibility of novel insight as an emergent feature of such metaphorical mappings. In order to assess whether personal insight can occur as a result of the consideration of dream content, 11 dream group discussion sessions were conducted which followed the Ullman Dream Appreciation technique, one session for each of 11 participants (10 females, 1 male; mean age = 19.2 years). Self-ratings of deepened self-perception and personal gains from participation in the group sessions showed that the Ullman technique is an effective procedure for establishing connections between dream content and recent waking life experiences, although wake life sources were found for only 14% of dream report text. The mean Exploration-Insight score on the Gains from Dream Interpretation questionnaire was very high and comparable to outcomes from the well-established Hill (1996) therapist-led dream interpretation method. This score was associated between-subjects with pre-group positive Attitude Toward Dreams (ATD). The need to distinguish “aha” experiences as a result of discovering a waking life source for part of a dream, from “aha” experiences of personal insight as a result of considering dream content, is discussed. Difficulties are described in designing a control condition to which the dream report condition can be compared

Comparing personal insight gains due to consideration of a recent dream and consideration of a recent event using the Ullman and Schredl dream group methods

There have been reports and claims in the psychotherapeutic literature that the consideration of recent dreams can result in personal realizations and insight. There is theoretical support for these claims from work on rapid eye movement (REM) sleep having a function of the consolidation of emotional memories and the creative formation of connections between new and older memories. To investigate these claims, 11 participants (10 females, one male) reported and considered a recent home dream in a dream discussion group that following the “Appreciating dreams” method of Montague Ullman. The group ran 11 times, each participant attending and participating once. A further nine participants (seven females, two males) reported and considered a recent home dream in a group that followed the “Listening to the dreamer” method of Michael Schredl. The two studies each had a control condition where the participant also reported a recent event, the consideration of which followed the same technique as was followed for the dream report. Outcomes of the discussions were assessed by the participants on the Gains from Dream Interpretation (GDI) scale, and on its counterpart, the Gains from Event Interpretation scale. High ratings on the GDI experiential-insight subscale were reported for both methods, when applied to dreams, and for the Ullman method Exploration-Insight ratings for the dream condition were significantly higher than for the control event condition. In the Ullman method, self-assessment of personal insight due to consideration of dream content was also significantly higher than for the event consideration condition. The findings support the view that benefits can be obtained from the consideration of dream content, in terms of identifying the waking life sources of dream content, and because personal insight may also occur. To investigate the mechanisms for the findings, the studies should be repeated with REM and non-REM dream reports, hypothesizing greater insight from the former

The Regeneration Games: Commodities, Gifts and the Economics of London 2012

This paper considers contradictions between two concurrent and tacit conceptions of the Olympic ‘legacy’, setting out one conception that understands the games and their legacies as gifts alongside and as counterpoint to the prevailing discourse, which conceives Olympic assets as commodities. The paper critically examines press and governmental discussion of legacy, in order to locate these in the context of a wider perspective contrasting ‘gift’ and ‘commodity’ Olympics – setting anthropological conceptions of gift-based sociality as a necessary supplement to contractual and dis-embedded socioeconomic organizational assumptions underpinning the commodity Olympics. Costbenefit planning is central to modern city building and mega-event delivery. The paper considers the insufficiency of this approach as the exclusive paradigm within which to frame and manage a dynamic socio-economic and cultural legacy arising from the 2012 games

Daydreams incorporate recent waking life concerns but do not show delayed (‘dream-lag’) incorporations

This study investigates the time course of incorporation of waking life experiences into daydreams. Thirty-one participants kept a diary for 10 days, reporting major daily activities (MDAs), personally significant events (PSEs) and major concerns (MCs). They were then cued for daydream, Rapid Eye Movement (REM) and N2 dream reports in the sleep laboratory. There was a higher incorporation into daydreams of MCs from the previous two days (day-residue effect), but no day-residue effect for MDAs or PSEs, supporting a function for daydreams of processing current concerns. A day-residue effect for PSEs and the delayed incorporation of PSEs from 5-7 days before the dream (the dream-lag effect) have previously been found for REM dreams. Delayed incorporation was not found in this study for daydreams. Daydreams might thus differ in function from REM sleep dreams. However, the REM dream-lag effect was not replicated here, possibly due to design differences from previous studies

Insight from the Consideration of REM dreams, Non-REM Dreams and Daydreams

Throughout history there have been reports and claims that consideration of dreams can produce personal realizations and insight. We assessed Exploration-Insight scores associated with discussing Rapid Eye Movement (REM) and non-REM (NREM) dreams in connection with recent waking life experiences. Thirty-one participants were cued in the sleep laboratory for a daydream report and then awakened from REM and N2 sleep for dream reports. Participants subsequently discussed each of their dream and daydream reports for 30-40 minutes with two experimenters, following the structured Ullman (1996) dream group discussion procedure. Participants assessed the benefit of discussing the reports by completing the Gains from (Day)Dream Interpretation (G(D)DI) questionnaire. We found no difference in G(D)DI scores between discussing REM and N2 dream reports, and no difference between dream and daydream discussions in engagement and thoroughness of exploring the reports. However, discussing dream reports produced higher scores on the G(D)DI Exploration-Insight subscale compared with discussing daydream reports. Significant differences were evident in items reflecting the learning of what the report means in terms of waking life issues. Frontal theta prior to waking from N2 was significantly associated with Exploration-Insight score obtained after N2 dream discussion, but this relationship was not found for REM dreams. The findings of high ratings of Exploration-Insight after discussing dreams were evident even though participants did not select the dream, unlike what can occur for home recorded dreams, and even though discussion was brief. We suggest that insight might be produced by embodied and metaphorical thinking in dreams