Teaching the mathematics that teachers need to know: Classroom ideas for supporting prospective elementary teachers’ development of mathematical knowledge for teaching

The goal of this article is to articulate aspects of mathematical knowledge for teaching (MKT) that should be addressed in college mathematics content courses for prospective teachers (PTs), and to make research- and practice-based recommendations of class activities, materials, and strategies in support of developing this knowledge. We describe class activities that engage PTs in problem solving as a means of making sense of the content that they will later teach and that immerse them in the mathematics practices that they will later need to foster with their own students. We also provide examples of how mathematics manipulatives, school curriculum materials, and samples of children’s thinking can be integrated as instructional tools in content courses. In developing these activities, we were guided by the research regarding the depth and breadth of knowledge required for the effective teaching of mathematics at the early childhood and upper elementary levels, and by the recommendations of professional organizations for math teacher education

Stac Proteins Suppress Ca2+-Dependent Inactivation of Neuronal L-type Ca2+ Channels

Stac protein (named for its SH3-and cysteine-rich domains) was first identified in brain 20 years ago and is currently known to have three isoforms. Stac2, Stac1, and Stac3 transcripts are found at high, modest, and very low levels, respectively, in the cerebellum and forebrain, but their neuronal functions have been little investigated. Here, we tested the effects of Stac proteins on neuronal, high-voltage-activated Ca2+ channels. Overexpression of the three Stac isoforms eliminated Ca2+-dependent inactivation (CDI) ofL-type current in rat neonatal hippocampal neurons (sex unknown), but not CDI of non-L-type current. Using heterologous expression in tsA201 cells (together with β and α2-δ1 auxiliary subunits), we found that CDI for CaV1.2 and CaV1.3 (the predominant, neuronalL-type Ca2+ channels) was suppressed by all three Stac isoforms, whereas CDI for the P/Q channel, CaV2.1, was not. For CaV1.2, the inhibition of CDI by the Stac proteins appeared to involve their direct interaction with the channel’s C terminus. Within the Stac proteins, a weakly conserved segment containing ~100 residues and linking the structurally conserved PKC C1 and SH3_1 domains was sufficient to fully suppress CDI. The presence of CDI forL-type current in control neonatal neurons raised the possibility that endogenous Stac levels are low in these neurons and Western blotting indicated that the expression of Stac2 was substantially increased in adult forebrain and cerebellum compared with neonate. Together, our results indicate that one likely function of neuronal Stac proteins is to tune Ca2+ entry via neuronal L-type channels. © 2018 the authors

1935: Abilene Christian College Bible Lectures - Full Text

Delivered in the auditorium of Abilene Christian College, Abilene, Texas, February 193

InGaAlAsPN: A Materials System for Silicon Based Optoelectronics and Heterostructure Device Technologies

A new material system is proposed for silicon based opto-electronic and heterostructure devices; the silicon lattice matched compositions of the (In,Ga,Al)-(As,P)N 3-5 compounds. In this nitride alloy material system, the bandgap is expected to be direct at the silicon lattice matched compositions with a bandgap range most likely to be in the infrared to visible. At lattice constants ranging between those of silicon carbide and silicon, a wider bandgap range is expected to be available and the high quality material obtained through lattice matching could enable applications such as monolithic color displays, high efficiency multi-junction solar cells, opto-electronic integrated circuits for fiber communications, and the transfer of existing 3-5 technology to silicon

Composite absorbing potentials

The multiple scattering interferences due to the addition of several contiguous potential units are used to construct composite absorbing potentials that absorb at an arbitrary set of incident momenta or for a broad momentum interval.Comment: 9 pages, Revtex, 2 postscript figures. Accepted in Phys. Rev. Let

Efficacy of a topical formulation of selamectin plus sarolaner against induced infestations of Amblyomma americanum on cats and prevention of Cytauxzoon felis transmission

Cytauxzoonosis, caused by infection with Cytauxzoon felis, is the most severe tick-borne disease of cats. The purpose of our study was to determine the efficacy of selamectin (6.0 mg/kg) plus sarolaner (1.0 mg/kg) formulated in combination (Revolution® Plus / Stronghold® Plus, Zoetis) applied topically once a month on cats for three months against induced infestations of Amblyomma americanum adults and to evaluate the effectiveness of the product in preventing the transmission of C. felis. This study was conducted in two phases. Sixteen cats were dosed with selamectin/sarolaner or a placebo (vehicle control) on Days 0, 28, and 56. In phase 1, each cat was infested with 50 (±5) unfed adult A. americanum on Day 4 and tick counts were conducted on Day 6 (48 h post infestation) and Day 7 (72 h post infestation) to evaluate acaricidal efficacy. In phase 2, to confirm acaricidal efficacy and evaluate prevention of C. felis transmission, each cat was infested on Day 60 with 50 (±5) adult A. americanum acquisition fed as nymphs on two C. felis-infected donor cats. Tick counts were conducted on Day 62 (48 h post infestation) and Day 63 (72 h post infestation). Blood samples were collected on Days -9, 60, 70, 76, and 90 and tested for infection with C. felis. Placebo cats were adequately infested on all count days, with least squares (geometric) mean live tick counts ranging from 34.0 (28.8) to 46.1 (46.0). Treatment reduced the least squares (geometric) mean counts compared to placebo by 27.1 (32.1)% and 90.4 (96.8)% on Days 6 and 7, respectively. The corresponding percent reductions were 56.4 (60.6)% and 94.7 (97.3)% on Days 62 and 63, respectively. Least squares mean counts were significantly lower in the treated group compared with the placebo group on all count days (P ≤ 0.0286). All cats were negative for C. felis by PCR prior to study start. In phase 2, seven cats in the control group and no cats in the selamectin/sarolaner group became infected with C. felis (P = 0.0017). Topical treatment with selamectin/sarolaner was \u3e90% effective in reducing A. americanum tick counts 72 h after infestation and prevented the transmission of C. felis from infected ticks following the third of three monthly treatments. Revolution® Plus / Stronghold® Plus offers an option for the control of A. americanum infestations on cats and for preventing the transmission of C. felis to cats

Search for fast particles produced at large lab angles at NAL

An experiment is proposed to look for charged particles emitted at large lab angles that are normally forbidden kinematically. These particles if found would correspond to hitherto unobserved events such as the production of particles with imaginary mass values (''tachyons''). Also, they wish to look for fractionally-charged particles produced at these angles. These particles, if found, would correspond to strongly-bound quark-quark states formed in a dissociation of the target nucleon. The detection system will consist of wire-chambers, dE/dx and time-of-flight counters. The basic hardware is under construction and the final system will be ready for test runs at a lower-energy machine in six months. The detection telescope will view interactions of the primary proton beam from backward (in lab) directions and the first choice experimental site is the straight section B with a thin internal target. They would like to use the highest available beam at NAL and since the beam transport and intensity requirements are very minimal, they will be able to run parasitically during the tuning periods of the NAL machine in the next year. The machine time required for this experiment is about three months

Robust Biophysical Parameter Estimation with a Neural Network Enhanced Hamiltonian Markov Chain Monte Carlo Sampler

Probabilistic parameter estimation in model fitting runs the gamut from maximum likelihood or maximum a posteriori point estimates from optimization to Markov Chain Monte Carlo (MCMC) sampling. The latter, while more computationally intensive, generally provides a better characterization of the underlying parameter distribution than that of point estimates. However, in order to efficiently explore distributions, MCMC methods ideally require generating uncorrelated samples while also preserving reasonable acceptance probabilities; this becomes particularly important in problematic regions of parameter space. In this paper, we extend a recently proposed Hamiltonian MCMC sampler parametrized by neural networks (L2HMC) by modifying the loss function to jointly optimize the distance between samples and the acceptance probability such that it is stable and efficient. We apply this enhanced sampler to parameter estimation in a recently proposed MRI model, the multi-echo spherical mean technique. We show that it generally outperforms the state of the art Hamiltonian No-U-Turn (NUTS) sampler, L2HMC, and a least squares fitting in terms of accuracy and precision, also enabling the generation of more informative parameter posterior distributions. This illustrates the potential of machine learning enhanced samplers for improving probabilistic parameter estimation for medical imaging applications

Expression of LIM kinase 1 is associated with reversible G1/S phase arrest, chromosomal instability and prostate cancer

<p>Abstract</p> <p>Background</p> <p>LIM kinase 1 (LIMK1), a LIM domain containing serine/threonine kinase, modulates actin dynamics through inactivation of the actin depolymerizing protein cofilin. Recent studies have indicated an important role of LIMK1 in growth and invasion of prostate and breast cancer cells; however, the molecular mechanism whereby LIMK1 induces tumor progression is unknown. In this study, we investigated the effects of ectopic expression of LIMK1 on cellular morphology, cell cycle progression and expression profile of LIMK1 in prostate tumors.</p> <p>Results</p> <p>Ectopic expression of LIMK1 in benign prostatic hyperplasia cells (BPH), which naturally express low levels of LIMK1, resulted in appearance of abnormal mitotic spindles, multiple centrosomes and smaller chromosomal masses. Furthermore, a transient G1/S phase arrest and delayed G2/M progression was observed in BPH cells expressing LIMK1. When treated with chemotherapeutic agent Taxol, no metaphase arrest was noted in these cells. We have also noted increased nuclear staining of LIMK1 in tumors with higher Gleason Scores and incidence of metastasis.</p> <p>Conclusion</p> <p>Our results show that increased expression of LIMK1 results in chromosomal abnormalities, aberrant cell cycle progression and alteration of normal cellular response to microtubule stabilizing agent Taxol; and that LIMK1 expression may be associated with cancerous phenotype of the prostate.</p