Jack Straton - Academia.edu (original) (raw)

Papers by Jack Straton

Student-centered learning requires teachers to provide students with opportunities to learn from ... more Student-centered learning requires teachers to provide students with opportunities to learn from and with each other, but most students come to group-work ill-equipped to handle the responsibility of cleanly communicating with each other. This paper provides one set of group-communication tools that helps students to become conscious molders of their own communication styles in relation to those of their peers

Many-Body Atomic Physics, 1998

$Research paper thumbnail of On the Production of the Positive Antihydrogen Ion <math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><msup><mover accent="true"><mi mathvariant="normal">H</mi><mo>ˉ</mo></mover><mo lspace="0em" rspace="0em">+</mo></msup></mrow><annotation encoding="application/x-tex">\bar{{\rm H}}^{+}</annotation></semantics></math>Hˉ+ via Radiative Attachment$

We provide an estimate of the cross section for the radiative attachment of a second positron int... more We provide an estimate of the cross section for the radiative attachment of a second positron into the (1s S) state of the H + ion using Ohmura and Ohmura’s (1960 Phys. Rev. 118 154) effective range theory and the principle of detailed balance. The H + ion can potentially be created using interactions of positrons with trapped antihydrogen, and our analysis includes a discussion in which estimates of production rates are given. Motivations to produce H + include its potential use as an intermediary to cool antihydrogen to ultra-cold (sub-mK) temperatures for a variety of studies, including spectroscopy and probing the gravitational interaction of the anti-atom.

Like many institutions of higher education, Portland State University (PSU) has engaged in initia... more Like many institutions of higher education, Portland State University (PSU) has engaged in initiatives to promote a more equitable and democratic society, from curricular changes to institutional policy implementation. In the late 1980s, PSU required students to complete a certain number of “diversity” credits as part of its general education requirements. During the 1990s, PSU radically revised its approach to general education, creating the University Studies Program that places diversity awareness among its core goals. Most recently, current President Daniel O. Bernstine has instituted a comprehensive “Diversity Initiative” as part of a series of initiatives aimed at improving the quality of university life for students, faculty, and staff. This paper recounts the institutional context for the University Studies Program’s emphasis on diversity, provides an overview of the University Studies general education curriculum, which is designed as a series of interdisciplinary learning ...

Multicultural Education, 2003

The European Physical Journal D, 2020

Atoms, 2020

To overcome the numerical difficulties inherent in the Maxwell–Boltzmann integral of the velocity... more To overcome the numerical difficulties inherent in the Maxwell–Boltzmann integral of the velocity-weighted cross section that gives the radiative attachment rate coefficient α R A for producing the negative hydrogen ion H - or its antimatter equivalent, the positive antihydrogen ion H ¯ + , we found the analytic form for this integral. This procedure is useful for temperatures below 700 K, the region for which the production of H ¯ + has potential use as an intermediate stage in the cooling of antihydrogen to ultra-cold (sub-mK) temperatures for spectroscopic studies and probing the gravitational interaction of the anti-atom. Our results, utilizing a 50-term explicitly correlated exponential wave function, confirm our prior numerical results.

$Research paper thumbnail of Utility of Precession Electron Diffraction Patterns with Varying Degrees of Non-parallel Illumination from the Same Nominal Sample Area$

Microscopy and Microanalysis, 2015

Diffraction of a primary electron beam that is precessing, i.e. Precession Electron Diffraction (... more Diffraction of a primary electron beam that is precessing, i.e. Precession Electron Diffraction (PED), in a Transmission Electron Microscope (TEM) [1-8], has over the last twenty-odd years become "an invaluable tool, not only for the determination of unknown crystal structures but also in aiding the analysis of local microstructure" [8]. Seven years after its first demonstration [9], the "scanning version of PED" [4-6] rivals in popularity electron backscattering in a scanning electron microscope.

Microscopy and Microanalysis, 2016

Crystallographic Image Processing (CIP) allows for the extraction of good estimates of the phases... more Crystallographic Image Processing (CIP) allows for the extraction of good estimates of the phases of the structure factors of many inorganic crystalline materials when the conditions of the (pseudo) weak phase object approximation are met in parallel-illumination high-resolution transmission electron microscopy (TEM) [1]. In atomic-resolution scanning TEM, CIP has been employed to remove noise from images and to confirm the average alkali-metal content per unit cell in a type I silicon clathrate [2]. The CIP technique has also been utilized to improve the signal to noise ratio (S/N) of scanning probe microscopy (SPM) images, reveal individual molecules more clearly [3,4], and remove the effects of multiple scanning probe mini-tips on a blunt scanning tunneling microscope (STM) tip from the images [5]. Because spatial averaging in CIP is done over all "asymmetric fraction" of all unit cells of regular 2D periodic arrays, this kind of noise removal from 2D periodic images is up to twelve times more effective [3,4] than traditional Fourier filtering [6].

$Research paper thumbnail of Producing the positive antihydrogen ion <math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><msup><mover accent="true"><mi mathvariant="normal">H</mi><mo>ˉ</mo></mover><mo lspace="0em" rspace="0em">+</mo></msup></mrow><annotation encoding="application/x-tex">{\bar{{\rm{H}}}}^{+}</annotation></semantics></math>Hˉ+ via radiative attachment$

Journal of Physics B: Atomic, Molecular and Optical Physics, 2016

AIP Conference Proceedings, 1997

Advanced Structural and Chemical Imaging, 2015

Crystallographic image processing (CIP) techniques may be utilized in scanning probe microscopy (... more Crystallographic image processing (CIP) techniques may be utilized in scanning probe microscopy (SPM) to glean information that has been obscured by signals from multiple probe tips. This may be of particular importance for scanning tunneling microscopy (STM) and requires images from samples that are periodic in two dimensions (2D). The image-forming current for double-tips in STM is derived with a slight modification of the independent-orbital approximation (IOA) to allow for two or more tips. Our analysis clarifies why crystallographic averaging works well in removing the effects of a blunt STM tip (that consists of multiple mini-tips) from recorded 2D periodic images and also outlines the limitations of this image-processing technique for certain spatial separations of STM double-tips. Simulations of multiple mini-tip effects in STM images (that ignore electron interference effects) may be understood as modeling multiple mini-tip (or tip shape) effects in images that were recorde...

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 1991

The charge sensitivity of this two-electron process is investigated as a tool for understanding c... more The charge sensitivity of this two-electron process is investigated as a tool for understanding correlation. The helium wave function is approximated by a sum of pair-products of one-electron wave functions, with the coefficients chosen by diagonalizing the fully correlated two-electron Hamiltonian. Thus. spatial correlation is included in both the asymptotic and scattering regions by using these configuration interaction (CI) wave functions for initial, intermedinte and final states, USC of CI wave functions also affows the first-order contributions to be expressed in closed, analytical form. Both the energy-conserving and energy-nonconserving parts of the second-order amphtude are found. The former (a correlated generalization of the independent electron approximation) is analytical and the latter is a one-dimensional integral. It is found that the double excitation cross sections are sensitive to the sign of the proJectlIe charge, but that the energy region where this sensitivity is of the same order as for double iomzation is 0.1 to 0.5 MeV,/amu, whereas the latter has peak charge sensitivity at 1.5 MeV/amu. Comparison 1s made with the experimental results of Prdersen and Hvelp~und [l] and Giese et al. 121.

Origins and Emphasis Though we teach on different teams-Jack on Pathways to Sustainability & Just... more Origins and Emphasis Though we teach on different teams-Jack on Pathways to Sustainability & Justice and Cherry on Sex, Mind & The Mask-our emphasis on extensive diversity training linked to social responsibility is quite similar. Jack teaches a 40-hour diversity curriculum that includes helping White 1 students to address the guilt that fixes them in inaction (Nile & Straton, 2003) and showing the movie The Color of Fear in which nine men of various ethnicities talk about their own experiences of race relations. Also included is "A Stand-up Exercise for Whites" (Kivel, 1992, p. 207-210) that puts them in touch with both the negative impact of White racism and the palpable reality of its prevalence. This course also explores the biological invalidity and the sociological reality of the concept of "race," and the need to move beyond a focus on interpersonal bigotry in an examination of race to challenging the institutions that remain the main obstacles to progress today by perpetuating discriminatory practices. Jack's particular challenge as a European-American teacher is crafting ways to use authentic voices to teach Students of Color how to cope with the daily indignities they face. Music is one key avenue for this.

Atoms

Quantum theory is awash in multidimensional integrals that contain exponentials in the integratio... more Quantum theory is awash in multidimensional integrals that contain exponentials in the integration variables, their inverses, and inverse polynomials of those variables. The present paper introduces a means to reduce pairs of such integrals to one dimension when the integrand contains powers multiplied by an arbitrary function of xy/(x+y) multiplying various combinations of exponentials. In some cases these exponentials arise directly from transition-amplitudes involving products of plane waves, hydrogenic wave functions, and Yukawa and/or Coulomb potentials. In other cases these exponentials arise from Gaussian transforms of such functions.