Teaching Replication to Graduate Students

Replicating published studies promotes active learning of quantitative research skills. Drawing on experiences from a replication course, we provide practical tips and reflections for teachers who consider incorporating replication in their courses. We discuss teaching practices and challenges we encountered at three stages of a replication course: student recruitment, course structure and proceedings, and learning outcomes. We highlight that by engaging in replication, students learn from established scholarly work in a collaborative and reflective manner. Students not only improve their quantitative literacy but also learn more generally about the scientific method and the production of research

Closed-cycle, low-vibration 4 K cryostat for ion traps and other applications

In-vacuo cryogenic environments are ideal for applications requiring both low temperatures and extremely low particle densities. This enables reaching long storage and coherence times for example in ion traps, essential requirements for experiments with highly charged ions, quantum computation, and optical clocks. We have developed a novel cryostat continuously refrigerated with a pulse-tube cryocooler and providing the lowest vibration level reported for such a closed-cycle system with 1 W cooling power for a <5 K experiment. A decoupling system suppresses vibrations from the cryocooler by three orders of magnitude down to a level of 10 nm peak amplitudes in the horizontal plane. Heat loads of about 40 W (at 45 K) and 1 W (at 4 K) are transferred from an experimental chamber, mounted on an optical table, to the cryocooler through a vacuum-insulated massive 120 kg inertial copper pendulum. The 1.4 m long pendulum allows installation of the cryocooler in a separate, acoustically isolated machine room. In the laser laboratory, we measured the residual vibrations using an interferometric setup. The positioning of the 4 K elements is reproduced to better than a few micrometer after a full thermal cycle to room temperature. Extreme high vacuum on the $10^{-15}$ mbar level is achieved. In collaboration with the Max-Planck-Intitut f\"ur Kernphysik (MPIK), such a setup is now in operation at the Physikalisch-Technische Bundesanstalt (PTB) for a next-generation optical clock experiment using highly charged ions

A Visual Query System for the Specification and Scientific Analysis of Continual Queries

The lack of a facility that would allow nonprogrammers to easily formulate temporal ad hoc analyses over a network of heterogeneous, constantly-updated data sources has been a significant impediment to research, particularly in the scientific community. In this paper we describe WebFormulate, an Internet-based system which facilitates the development of analyses using information obtained from databases on the Internet. The main distinction between this system and existing Internet facilities to retrieve information and assimilate it into computations is that WebFormulate provides the necessary facilities to perform continual queries, developing and maintaining dynamic links such that computations and reports automatically maintain themselves. A further distinction is that this system is specifically designed for users of spreadsheet-level ability, rather than professional programmers

Promoting cognitive support technology use and employment success among postsecondary students with traumatic brain injuries

OBJECTIVE: This article applies positive psychology principles to the purpose and objectives of a five-year, federally-funded initiative to provide cognitive support technology (CST) training and career preparatory services for undergraduate college students with mild and moderate traumatic brain injuries (TBI). METHODS: A total of 48 students with TBI have participated in the project during its first 18 months of operation - 14 of whom are military veterans with disabilities who were in the Iraq and/or Afghanistan theaters. CONCLUSION: Positive psychology interventions such as Best Possible Self, Intensely Positive Experiences, and Asset-based Assessments provide a framework for examining the activities of this multi-site development project

Optical and Electrochemical Properties of Multi-layer Polyelectrolyte Thin Films Incorporating Spherical, Gold Colloid Nanomaterials

Polyelectrolyte multilayer (PEM) films incorporating various types of spherical, gold nanomaterials (NMs) were investigated to assess the existence of electrochemical and/or optical signal enhancement effects directly attributable to embedded NMs and the relationship of these effects to film structure and composition. Specifically, electrostatically assembled films of cationic poly-L-lysine (PLL) and anionic poly(4-styrene sulfonate) (PSS) incorporating one of four types of spherical, gold colloid NMs were constructed on 3-(aminopropyl)trimethoxysilane (3-APTMS)-modified glass substrates for optical studies or 11-mercaptoundecanoic (MUA)-modified gold electrodes for electrochemical studies. The NMs inserted into the PEM films include citrate-stabilized gold nanoparticles, thioctic acid-stabilized gold nanoparticles (TAS-NPs), MUA-modified monolayer protected gold clusters, and hollow gold nanoshells (Au-NSs). Optical sensitivity of the NM-embedded films, in terms of absorbance, surface plasmon band shifts, and the dependence of these optical responses on film thickness, varied depending on the type of NM within the film (e.g., TAS-NPs versus Au-NSs) but exhibited no corresponding electrochemical effects in the diffusional voltammetry of a ferricyanide redox probe. While not correlated to optical responses, the increased Faradaic current achieved during voltammetry at NM-embedded PEM films suggested that electrochemical effects of NMs were less dependent on the type of NMs and were, instead, more related to their location within the film and the electrostatic interactions built into the interfacial chemistry of the films. These results should prove useful for developing strategies constructing thin films with NMs that are specifically designed for optical or electrochemical sensing, taking full advantage of the signal enhancements provided by individual types of NMs

Reducing multiphoton ionization in a linearly polarized microwave field by local control

We present a control procedure to reduce the stochastic ionization of hydrogen atom in a strong microwave field by adding to the original Hamiltonian a comparatively small control term which might consist of an additional set of microwave fields. This modification restores select invariant tori in the dynamics and prevents ionization. We demonstrate the procedure on the one-dimensional model of microwave ionization.Comment: 8 page

Sweep, Step, Pulse, and Frequency-Based Techniques Applied to Protein Monolayer Electrochemistry at Nanoparticle Interfaces

Protein monolayer electrochemistry (PME), a strategy using synthetic platforms to study the electron transfer (ET) properties of adsorbed proteins, has been successfully applied to proteins adsorbed at monolayer-protected gold cluster (MPCs) assembled films, an adsorption interface shown to be an effective alternative, compared to traditional self-assembled monolayer (SAM) films, for the immobilization and study of ET proteins. Within PME studies, cyclic voltammetry (CV) remains the most commonly applied electrochemical technique in spite of several limitations that occur when the sweep technique is used at either platform. In particular, CV for PME at MPC films results in analysis complications stemming from the increased charging current inherent to electrochemical interfaces incorporating MPCs with capacitive properties. In this study, multiple electroanalytical techniques, involving step (chronocoulometry, CC), pulse (square wave voltammetry, SWV), and frequency-based impedance (electrochemical impedance spectroscopy, EIS) measurements, are applied to monolayers of adsorbed Pseudomonas aeruginosa azurin and horse heart cytochrome c at both MPC film assemblies as well as traditional SAMs. Electrochemical parameters (formal potential, electroactive surface coverage, double-layer capacitance, and ET rate constant) measured from these various techniques are directly compared and offer insight into the performance and reliability of each technique’s effectiveness in PME. While certain techniques result in measurements indistinguishable from CV, others offer distinct differences. Moreover, the application of alternative techniques reveals systemic limitations and complications within the electrochemical analysis that we further explore, including strategies for applying fast scanning techniques like SWV as well as the construction of MPC platforms with controlled levels of charging current that enable successful impedance analysis. The application of more advanced electrochemical techniques to developing electrochemical interfaces such as MPC film assemblies allows for a greater understanding of not only PME but also the applicability and effectiveness of these techniques to optimize the measurement of specific electrochemical parameters