Sharing a Context with Other Rewarding Events Increases the Probability that Neutral Events will be Recollected.

Although reward is known to enhance memory for reward-predicting events, the extent to which such memory effects spread to associated (neutral) events is unclear. Using a between-subject design, we examined how sharing a background context with rewarding events influenced memory for motivationally neutral events (tested after a 5 days delay). We found that sharing a visually rich context with rewarding objects during encoding increased the probability that neutral objects would be successfully recollected during memory test, as opposed to merely being recognized without any recall of associative detail. In contrast, such an effect was not seen when the context was not explicitly demarcated and objects were presented against a blank black background. These qualitative changes in memory were observed in the absence of any effects on overall recognition (as measured by d'). Additionally, a follow-up study failed to find any evidence to suggest that the mere presence of a context picture in the background during encoding (i.e., without the reward manipulation) produced any such qualitative changes in memory. These results suggest that reward enhances recollection for rewarding objects as well as other non-rewarding events that are representationally linked to the same context

Interaction-induced shift of the cyclotron resonance of graphene using infrared spectroscopy

We report a study of the cyclotron resonance (CR) transitions to and from the unusual $n=0$ Landau level (LL) in monolayer graphene. Unexpectedly, we find the CR transition energy exhibits large (up to 10%) and non-monotonic shifts as a function of the LL filling factor, with the energy being largest at half-filling of the $n=0$ level. The magnitude of these shifts, and their magnetic field dependence, suggests that an interaction-enhanced energy gap opens in the $n=0$ level at high magnetic fields. Such interaction effects normally have limited impact on the CR due to Kohn's theorem [W. Kohn, Phys. Rev. {\bf 123}, 1242 (1961)], which does not apply in graphene as a consequence of the underlying linear band structure.Comment: 4 pages, 4 figures. Version 2, edited for publication. Includes a number of edits for clarity; also added a paragraph contrasting our work w/ previous CR expts. in 2D Si and GaA

Delayed Complications of Emergency Airway Management: A Study of 533 Emergency Department Intubations

OBJECTIVES: Airway management is a critical procedure performed frequently in emergency departments (EDs). Previous studies have evaluated the complications associated with this procedure but have focused only on the immediate complications. The purpose of this study is to determine the incidence and nature of delayed complications of tracheal intubation performed in the ED at an academic center where intubations are performed by emergency physicians (EPs).METHODS: All tracheal intubations performed in the ED over a one-year period were identified; 540 tracheal intubations were performed during the study period. Of these, 523 charts (96.9%) were available for review and were retrospectively examined. Using a structured datasheet, delayed complications occurring within seven days of intubation were abstracted from the medical record. Charts were scrutinized for the following complications: acute myocardial infarction (MI), stroke, airway trauma from the intubation, and new respiratory infections. An additional 30 consecutive intubations were examined for the same complications in a prospective arm over a 29-day period.RESULTS: The overall success rate for tracheal intubation in the entire study group was 99.3% (549/553). Three patients who could not be orally intubated underwent emergent cricothyrotomy. Thus, the airway was successfully secured in 99.8% (552/553) of the patients requiring intubation. One patient, a seven-month-old infant, had unanticipated subglottic stenosis and could not be intubated by the emergency medicine attending or the anesthesiology attending. The patient was mask ventilated and was transported to the operating room for an emergent tracheotomy. Thirty-four patients (6.2% [95% CI 4.3 - 8.5%]) developed a new respiratory infection within seven days of intubation. Only 18 patients (3.3% [95% CI 1.9 - 5.1%]) had evidence of a new respiratory infection within 48 hours, indicating possible aspiration pneumonia secondary to airway management. Three patients (0.5% [95% CI 0.1 - 1.6%]) suffered an acute MI, but none appeared to be related to the intubation. One patient was having an acute MI at the time of intubation and the other two patients had MIs more than 24 hours after the intubation. No patient suffered a stroke (0% [95% CI 0 - 0.6%]). No patients suffered any serious airway trauma such as a laryngeal or vocal cord injury.CONCLUSIONS: Emergency tracheal intubation in the ED is associated with an extremely high success rate and a very low rate of delayed complications. Complication rates identified in this study compare favorably to reports of emergency intubations in other hospital settings. Tracheal intubation can safely be performed by trained EPs

Advection, diffusion and delivery over a network

Many biological, geophysical and technological systems involve the transport of resource over a network. In this paper we present an algorithm for calculating the exact concentration of resource at any point in space or time, given that the resource in the network is lost or delivered out of the network at a given rate, while being subject to advection and diffusion. We consider the implications of advection, diffusion and delivery for simple models of glucose delivery through a vascular network, and conclude that in certain circumstances, increasing the volume of blood and the number of glucose transporters can actually decrease the total rate of glucose delivery. We also consider the case of empirically determined fungal networks, and analyze the distribution of resource that emerges as such networks grow over time. Fungal growth involves the expansion of fluid filled vessels, which necessarily involves the movement of fluid. In three empirically determined fungal networks we found that the minimum currents consistent with the observed growth would effectively transport resource throughout the network over the time-scale of growth. This suggests that in foraging fungi, the active transport mechanisms observed in the growing tips may not be required for long range transport.Comment: 54 pages including appendix, 10 figure

A model of hyphal tip growth involving microtubule-based transport

We propose a simple model for mass transport within a fungal hypha and its subsequent growth. Inspired by the role of microtubule-transported vesicles, we embody the internal dynamics of mass inside a hypha with mutually excluding particles progressing stochastically along a growing one-dimensional lattice. The connection between long range transport of materials for growth, and the resulting extension of the hyphal tip has not previously been addressed in the modelling literature. We derive and analyse mean-field equations for the model and present a phase diagram of its steady state behaviour, which we compare to simulations. We discuss our results in the context of the filamentous fungus, Neurospora crassa.Comment: 5 pages, 5 figure

One, two, or three stars? An investigation of an unusual eclipsing binary candidate undergoing dramatic period changes

We report our investigation of 1SWASP J234401.81-212229.1, a variable with a 18 461.6 s period. After identification in a 2011 search of the SuperWASP archive for main-sequence eclipsing binary candidates near the distribution's short-period limit of ~0.20 d, it was measured to be undergoing rapid period decrease in our earlier work, though later observations supported a cyclic variation in period length. Spectroscopic data obtained in 2012 with the Southern African Large Telescope did not, however, support the interpretation of the object as a normal eclipsing binary. Here, we consider three possible explanations consistent with the data: a single-star oblique rotator model in which variability results from stable cool spots on opposite magnetic poles; a two-star model in which the secondary is a brown dwarf; and a three-star model involving a low-mass eclipsing binary in a hierarchical triple system. We conclude that the latter is the most likely model

Antibody mimetic receptor proteins for label-free biosensors

The development of high sensitivity biosensors, for example for clinical diagnostics, requires the identification of suitable receptor molecules which offer high stability, specificity and affinity, even when embedded into solid-state biosensor transducers. Here, we present an electrochemical biosensor employing small synthetic receptor proteins (Mw < 15 kDa) which emulate antibodies but with improved stability, sensitivity and molecular recognition properties, in particular when immobilized on a solid sensor surface. The synthetic receptor protein is a non-antibody-based protein scaffold with variable peptide regions inserted to provide the specific binding, and was designed to bind anti-myc tag antibody (Mw � 150 kDa), as a proof-of-principle exemplar. Both the scaffold and the selected receptor protein were found to have high thermostability with melting temperatures of 101 �C and 85 �C, respectively. Furthermore, the secondary structures of the receptor protein were found to be very similar to that of the original native scaffold, despite the insertion of variable peptide loops that create the binding sites. A label-free electrochemical sensor was fabricated by functionalising a microfabricated gold electrode with the receptor protein. A change in the phase of the electrochemical impedance was observed when the biosensor was subjected to anti-myc tag antibodies at concentrations between 6.7 pM and 6.7 nM. These findings demonstrate that these non-antibody receptor proteins are excellent candidates for recognition molecules in label-free biosensors