Lensing reconstruction from line intensity maps: the impact of gravitational nonlinearity

We investigate the detection prospects for gravitational lensing of three-dimensional maps from upcoming line intensity surveys, focusing in particular on the impact of gravitational nonlinearities on standard quadratic lensing estimators. Using perturbation theory, we show that these nonlinearities can provide a significant contaminant to lensing reconstruction, even for observations at reionization-era redshifts. However, we show how this contamination can be mitigated with the use of a "bias-hardened" estimator. Along the way, we present an estimator for reconstructing long-wavelength density modes, in the spirit of the "tidal reconstruction" technique that has been proposed elsewhere, and discuss the dominant biases on this estimator. After applying bias-hardening, we find that a detection of the lensing potential power spectrum will still be challenging for the first phase of SKA-Low, CHIME, and HIRAX, with gravitational nonlinearities decreasing the signal to noise by a factor of a few compared to forecasts that ignore these effects. On the other hand, cross-correlations between lensing and galaxy clustering or cosmic shear from a large photometric survey look promising, provided that systematics can be sufficiently controlled. We reach similar conclusions for a single-dish survey inspired by CII measurements planned for CCAT-prime, suggesting that lensing is an interesting science target not just for 21cm surveys, but also for intensity maps of other lines.Comment: 40+18 pages, 13 figures, 5 tables. v2: JCAP published version, with typos fixed and clarifications adde

Pausing of Children during Signaled and Unsignaled Transitions

We evaluated effects of signaled and unsignaled transitions between reinforcement schedules on pausing and run rates of academic responding and rate and duration of problem behavior for four children who engaged in chronic and severe problem behavior. Children completed an academic task on a computer program to earn access to brief video clips. Lean (more responses and short videos) and rich (few responses and long videos) reinforcement schedules were alternated within each session, creating four transition types: lean-to-lean, lean-to-rich, rich-to-rich, and rich-to-lean. Pausing was measured as the latency to initiate the first response of a reinforcement schedule. Run rates were calculated as responses per minute (minus pause durations). The rate and percentage of transitions with problem behavior during each transition type were also calculated. The results of all measures were idiosyncratic across participants. Potential explanations for the idiosyncratic results are discussed

Evaluating Treatment Integrity Failures during Timeout from Play

Timeout is an effective behavior-reduction strategy with considerable generality. There are several recommendations about how to implement timeout. However, little research has investigated how timeout is implemented under natural conditions, or how timeout-implementation errors impact its effectiveness. Thus, our study attempted to address two aims. The first aim was to observe how teachers implemented timeout with their students. To address this aim (Experiment 1), we completed naturalistic observations of teachers who were implementing timeout during play. We collected data on how frequently the teachers implemented timeout following problem behavior (omission integrity), and how frequently teachers implemented timeout following responses not targeted for timeout (commission integrity). Experiment 1 data showed that teachers rarely implemented timeout; when the teachers did implement timeout, they often did not follow the timeout parameters specified initially. The second aim was to evaluate what effects inconsistent timeout implementation has on student behavior. To address this aim (Experiment 2), we evaluated the effects of inconsistent timeout on rates of problem behavior. Specifically, we used a reversal design to compare implementation of timeout at 0%, 100%, and reduced integrity (e.g., 11% integrity). The specific level of integrity implemented during the reduced-integrity phases was based upon the omission integrity observed for each student during Experiment 1. The data from Experiment 2 showed that timeout implemented with high integrity decreased problem behavior for two of four students. For one student, reduced-integrity implementation also decreased problem behavior. Due to low rates of problem behavior and participant attrition, three of four participants did not complete Experiment 2. Although our conclusions are limited, these data allowed us to make clinical recommendations about how the teachers should implement timeout with their students. Our results also have important implications for the application of timeout in schools and for future research

Slow Rate Sand Filtration With and Without Clinoptilolite: A Comparison of Water Quality and Filtration Economics

Slow rate sand filtration (SSF) amended with a 20 em surface layer of clinoptilolite, a natural zeolite, was compared to SSF with no amendment in a field scale SSF facility treating 85 m3/d of water. Parameters examined included turbidity, coliforms, and ammonium removal. The control filter with sand and the experimental filter amended with the zeolite were also compared with respect to duration of filter cycle, cold weather operation, and economics. Amended and unamended filters were appr oximately equivalent with respect to ammonium and coliform removal at 10° C. The zeolite amended cell was superior to the unamended cell with respect to coliform and turbidity removal at 3° C. The zeolite amended cell had filter cycle durations four times longer and operation and maintenance costs 25% lower than the unamended cell. Laboratory column studies were also conducted to compare a control column of construction sand to a homogeneous sand-zeolite mixture. and to SSF amended with zeolite or coarse sand. Construction sand and clinoptilolite were very similar in metal removal efficiency. Head loss developed most rapidly in the SSF column with construction sand only. Head loss developed more slowly resulting in longer filter cycles when the SSF was amended with a zeolite or coarse sand surface layer. A homogeneous sand-clinoptilolite mixture had filter cycles longer than construction sand, but shorter than SSF amended with a coarse surface medium. Batch reactor tests were utilized to compare adsorption of reovirus to sand and clinoptilolite. Reovirus adsorption was approximately equivalent for the two media

A priori information and optimisation in polarimetry

Published versio

STARRY: Analytic Occultation Light Curves

We derive analytic, closed form, numerically stable solutions for the total flux received from a spherical planet, moon or star during an occultation if the specific intensity map of the body is expressed as a sum of spherical harmonics. Our expressions are valid to arbitrary degree and may be computed recursively for speed. The formalism we develop here applies to the computation of stellar transit light curves, planetary secondary eclipse light curves, and planet-planet/planet-moon occultation light curves, as well as thermal (rotational) phase curves. In this paper we also introduce STARRY, an open-source package written in C++ and wrapped in Python that computes these light curves. The algorithm in STARRY is six orders of magnitude faster than direct numerical integration and several orders of magnitude more precise. STARRY also computes analytic derivatives of the light curves with respect to all input parameters for use in gradient-based optimization and inference, such as Hamiltonian Monte Carlo (HMC), allowing users to quickly and efficiently fit observed light curves to infer properties of a celestial body's surface map.Comment: 55 pages, 20 figures. Accepted to the Astronomical Journal. Check out the code at https://github.com/rodluger/starr

Photon statistics in single molecule orientational imaging

Published versio

Eigenfunction expansion of the electric fields in the focal region of a high numerical aperture focusing system

Published versio

Hyperresponsiveness in the human nasal airway: new targets for the treatment of allergic airway disease.

Allergic rhinitis is a condition which affects over 15% of the population in the United Kingdom. The pathological process involves two stages: nasal inflammation, and the development of nasal airway hyperresponsiveness (AHR) to allergen and a number of other stimuli. This results in the amplification of any subsequent allergic reaction, contributing to the chronic allergic state. A number of different hypotheses have been proposed to explain the underlying mechanism of AHR, including a role for eosinophil-derived proteins, free radicals and neuropeptides. While there may be a number of independent pathways which can result in AHR, evidence obtained from both animal models and in vivo experiments in humans indicate that some mediators may interact with one another, resulting in AHR. Further research into these interactions may open new avenues for the pharmacological treatment of chronic allergic rhinitis, and possibly other allergic airway diseases