We present a method for tracking radio-tagged pebbles and cobbles through subglacial meltwater channels under shallow temperate glaciers. Natural particles tagged with active radio transmitters were injected directly into a large subglacial channel 300 m up-glacier from the terminus of the Glacier d'Otemma, Switzerland. A roving antenna was developed to localise tagged particles planimetrically in subglacial and proglacial channel reaches (350 and 150 m long, respectively) using a probabilistic technique, delivering records of the change in particle location and transport distance over time with uncertainty. The roving antenna had a ±5−15 m planimetric precision, a 75% particle localisation rate and operated at a maximum ice depth of 47 m. Additionally, stationary supraglacial and proglacial antennas continuously monitored the passage of tagged particles through consecutive reaches of the channel, constraining the timing of particle transport events. The proglacial antenna system had a 98.1% detection rate and was operational to 0.89 m water depth during testing. Roving and stationary antenna records were combined to create a transport distance model for each particle, which may be used in conjunction with hydraulic data to investigate the kinematics of particle motion. When applied at scale in future studies, this method may be used to reveal the mechanisms and timescales of coarse sediment export from Alpine glaciers.

We introduce a novel amortised resource analysis couched in a type-and-effect system. Our analysis is formulated in terms of the physicist’s method of amortised analysis and is potentialbased. The type system makes use of logarithmic potential functions and is the first such system to exhibit logarithmic amortised complexity. With our approach, we target the automated analysis of self-adjusting data structures, like splay trees, which so far have only manually been analysed in the literature. In particular, we have implemented a semi-automated prototype, which successfully analyses the zig-zig case of splaying, once the type annotations are fixed.

The Hawthorne Effect is a prevalent observer effect that causes behavioral changes among participants of epidemiological studies or infection control interventions. The purpose of the review is to describe the origins of the Hawthorne Effect, to understand the term in relation to current scientific literature, to describe characteristics of the Hawthorne effect, and to discuss methods to quantify and overcome limitations associated with the Hawthorne Effect.

Infect. Control Hosp. Epidemiol. 2015;36(12):1444–1450

Using suction electrodes, photocurrent responses to 100-ms saturating flashes were recorded from isolated retinal rods of the larval-stage tiger salamander (Ambystoma tigrinum). The delay period (Te) that preceded recovery of the dark current by a criterion amount (3 pA) was analyzed in relation to the flash intensity (If), and to the corresponding fractional bleach (R*0/Rtot) of the visual pigment; R*0/Rtot was compared with R*s/Rtot the fractional bleach at which the peak level of activated transducin approaches saturation. Over an approximately 8 In unit range of If that included the predicted value of R*s/Rtot, Te increased linearly with In If. Within the linear range, the slope of the function yielded an apparent exponential time constant (TC) of 1.7 ± 0.2 s (mean ± S.D.). Background light reduced the value of Tc measured at a given flash intensity but preserved a range over which Tc increased linearly with In If; the linear-range slope was similar to that measured in the absence of background light. The intensity dependence of Tc resembles that of a delay (Td) seen in light-scattering experiments on bovine retinas, which describes the period of essentially complete activation of transducin following a bright flash; the slope of the function relating Td and In flash intensity is thought to reflect the lifetime of photoactivated visual pigment (R*) (Pepperberg et al., 1988; Kahlert et al., 1990). The present data suggest that the electrophysiological delay has a similar basis in the deactivation kinetics of R*, and that Tc represents TR* the lifetime of R* in the phototransduction process. The results furthermore suggest a preservation of the “dark-adapted” value of TR* within the investigated range of background intensity.

Linear typing schemes can be used to guarantee non-interference and so the soundness of in-place update with respect to a functional semantics. But linear schemes are restrictive in practice, and more restrictive than necessary to guarantee soundness of in-place update. This limitation has prompted research into static analysis and more sophisticated typing disciplines to determine when in-place update may be safely used, or to combine linear and non-linear schemes. Here we contribute to this direction by defining a new typing scheme that better approximates the semantic property of soundness of in-place update for a functional semantics. We begin from the observation that some data are used only in a “read-only” context, after which it may be safely re-used before being destroyed. Formalising the in-place update interpretation in a machine model semantics allows us to refine this observation, motivating three usage aspects apparent from the semantics that are used to annotate function argument types. The aspects are (1) used destructively, (2), used read-only but shared with result, and (3) used read-only and not shared with the result. The main novelty is aspect (2), which allows a linear value to be safely read and even aliased with a result of a function without being consumed. This novelty makes our type system more expressive than previous systems for functional languages in the literature. The system remains simple and intuitive, but it enjoys a strong soundness property whose proof is non-trivial. Moreover, our analysis features principal types and feasible type reconstruction, as shown in M. Konečn'y (In TYPES 2002 workshop, Nijmegen, Proceedings, Springer-Verlag, 2003).

Vanadium nitride has been synthesized with a surface area of 120 m2 g−1 by temperature programmed nitridation of a foam-like vanadium oxide (35 m2 g−1), precipitated from vanadate solutions. The nitridation reaction was established to be topotactic and pseudomorphous by x-ray powder diffraction and scanning electron microscopy. The crystallographic relationship between the nitride and oxide was {200}//{001}. The effect of precursor geometry on the product size and shape was investigated by employing vanadium oxide solids of different morphologies.