Unimolecular reaction rates in solution and in the isolated molecule: Comparison of diphenyl butadiene nonradiative decay in solutions and supersonic jets

The recent study of diphenyl butadiene (DPB) in supersonic jets and in solution by Shepanski et al.(1) and by Courtney and Felming(2), respectively, provides an opportunity to compare the isomerization rates measured in the isolated molecule (jet) with those measured at very low viscosity in solution. These comparisons should shed light on the vibrational energy flows between “optical” and “reactive” modes in the isolated molecule and on the connection between activated, friction dependent, models of barrier crossing in solution,(3-5) and statistical RRK (or RRKM) theories of gas phase unimolecular reactions(6)

Determining the Number of Factors to Retain in EFA: Using the SPSS R-Menu v2 0 to Make More Judicious Estimations

Exploratory factor analysis (EFA) is a common technique utilized in the development of assessment instruments. The key question when performing this procedure is how to best estimate the number of factors to retain. This is especially important as under- or over-extraction may lead to erroneous conclusions. Although recent advancements have been made to answer the number of factors question, popular statistical packages do not come standard with these modern techniques. This paper details how to program IBM SPSS Statistics software (SPSS) to conveniently perform five modern techniques designed to estimate the number of factors to retain. By utilizing the five empirically-supported techniques illustrated in this article, researchers will be able to more judiciously model data. Accessed 27,874 times on https://pareonline.net from April 30, 2013 to December 31, 2019. For downloads from January 1, 2020 forward, please click on the PlumX Metrics link to the right

Feed Efficiency in Growing Steers: Relationships between Efficiency and Carcass Ultrasound Traits

Phenotypic correlations between feed efficiency and carcass traits were examined in growing steers. Two feed efficiency trials were conducted using 233 Santa Gertrudis steers. Steers were individually fed a roughage-based for 77days. Individual feed intake was recorded weekly and body weight was measured bi-weekly. Ultrasound measurements of the 12th rib fat thickness (back fat), longissimus muscle area (REA) and percentage intramuscular fat were obtained on day 0 and 77, Residual feed intake (RFIp) is a measure of feed efficiency that attempts to measure variation in feed intake beyond that needed for growth and maintenance. Residual feed intake was calculated as the difference between actual feed intake and expected feed intake predicted by a linear regression model of dry matter intake (DMI) on mid-test BW0.75 (MBW) and average daily gain (ADG) with trial, trial × MBW, and trial × ADG as random effects. Steers were ranked by RFI into low, medium, and high RFI groups \u3c0.5 SD, ± 0.5, \u3e 0.5 SD, respectively, from the mean RFIp of 0.0 ± 1.01 kg/d. Overall means for ADG and DMI were 0.38 (SD = 0.57) and 9.79 (SD = 1.03), respectively. Stepwise regression indicated that inclusion of gain in back fat (GBF) into the base model increased the r2 (0.29 vs. 31). RFIp was positively correlated (P \u3c 0.5) with DMI (r = 0.85), and FCR (r = 0.47), but not with MBW or ADG. Feed to gain ratio (FCR) was negatively correlated (P \u3c 0.05) with ADG (r = -0.82). Carcass adjusted for RFI (RFIc) was not correlated with ADG, DMI, MBW, or FCR. Carcass ultrasound traits were not correlated (P \u3e 0.05) with feed efficiency traits. Gain in back fat was positively correlated with (P \u3c 0.05) with RFIp (r = 0.17), but not correlated (P \u3e 0.05) with FCR or RFIc. Gain in REA was negatively correlated (P \u3c 0.05) with FCR (r = -0.21) and RFIc (r = -0.17), but not with RFIp. The Spearman rank correlation between RFIp and RFIc was high (r = 0.91). Results suggest that RFI is independent of growth rate and mature size, but related to DMI. Selecting for favorable RFIp phenotypes can potentially improve feed efficiency in cattle. Adjusting RFI for ultrasound carcass traits could also improve feed efficiency independent of growth, body size, and carcass composition

How Does Training From a STEM Elementary Education Program Influence an Elementary Teacher’s Instruction and Experiences?

In the United States, innovation and our economy seem to be lacking in comparison to other countries. Many cite the shortage of individuals interested in STEM careers as part of the problem. The following research article addresses how STEM programs may influence the efficacy and practice of curriculum integration as well as the mathematics and science instruction of teachers in elementary education. Data were collected using interviews and taped instruction from an elementary educator who graduated from a STEM-focused elementary program. This exploratory case study will aid in understanding how preservice programs focusing on STEM-integrated curriculum in elementary education can have a positive or negative influence on teachers’ understanding and implementation of STEM-integrated curriculum

Hundred photon microwave ionization of Rydberg atoms in a static electric field

We present analytical and numerical results for the microwave excitation of nonhydrogenic atoms in a static electric field when up to 1000 photons are required to ionize an atom. For small microwave fields, dynamical localization in photon number leads to exponentially small ionization while above quantum delocalization border ionization goes in a diffusive way. For alkali atoms in a static field the ionization border is much lower than in hydrogen due to internal chaos.Comment: revtex, 4 pages, 5 figure

Quantifying the Reconfiguration of Intrinsic Networks during Working Memory

Rapid, flexible reconfiguration of connections across brain regions is thought to underlie successful cognitive control. Two intrinsic networks in particular, the cingulo-opercular (CO) and fronto-parietal (FP), are thought to underlie two operations critical for cognitive control: task-set maintenance/tonic alertness and adaptive, trial-by-trial updating. Using functional magnetic resonance imaging, we directly tested whether the functional connectivity of the CO and FP networks was related to cognitive demands and behavior. We focused on working memory because of evidence that during working memory tasks the entire brain becomes more integrated. When specifically probing the CO and FP cognitive control networks, we found that individual regions of both intrinsic networks were active during working memory and, as expected, integration across the two networks increased during task blocks that required cognitive control. Crucially, increased integration between each of the cognitive control networks and a task-related, non-cognitive control network (the hand somatosensory-motor network; SM) was related to increased accuracy. This implies that dynamic reconfiguration of the CO and FP networks so as to increase their inter-network communication underlies successful working memory

Symmetry breaking in crossed magnetic and electric fields

We present the first observations of cylindrical symmetry breaking in highly excited diamagnetic hydrogen with a small crossed electric field, and we give a semiclassical interpretation of this effect. As the small perpendicular electric field is added, the recurrence strengths of closed orbits decrease smoothly to a minimum, and revive again. This phenomenon, caused by interference among the electron waves that return to the nucleus, can be computed from the azimuthal dependence of the classical closed orbits.Comment: 4 page REVTeX file including 5 postscript files (using psfig) Accepted for publication in Physical Review Letters. Difference from earlier preprint: we have discovered the cause of the earlier apparent discrepancy between experiment and theory and now achieve excellent agreemen

First-principles prediction of redox potentials in transition-metal compounds with LDA+U

First-principles calculations within the Local Density Approximation (LDA) or Generalized Gradient Approximation (GGA), though very successful, are known to underestimate redox potentials, such as those at which lithium intercalates in transition metal compounds. We argue that this inaccuracy is related to the lack of cancellation of electron self-interaction errors in LDA/GGA and can be improved by using the DFT+$U$ method with a self-consistent evaluation of the $U$ parameter. We show that, using this approach, the experimental lithium intercalation voltages of a number of transition metal compounds, including the olivine Li$_{x}$MPO$_{4}$ (M=Mn, Fe Co, Ni), layered Li$_{x}$MO$_{2}$ ($x=$Co, Ni) and spinel-like Li$_{x}$M$_{2}$O$_{4}$ (M=Mn, Co), can be reproduced accurately.Comment: 19 pages, 6 figures, Phys. Rev. B 70, 235121 (2004

Relationship between Temperament and Performance Traits in Yearling Cattle

To examine relationships between exit velocity (EV, objective measure of temperament) and performance traits, calves were weighed 14 days prior to weaning, at weaning, 128 days post weaning, and at time of carcass measurements. Exit velocity obtained on day -14 and carcass ultrasound measurements (n = 6) obtained on day 208 and carcass harvest measurements (n = 12) obtained on day 349 were used to determine correlations between EV, performance and carcass measurements. Exit velocity showed a tendency to be negatively correlated (P \u3c 0.15) with weaning weight (r = -0.40), but not correlated (P \u3e 0.05) with average daily gain post 128 days. Exit velocity was not correlated (P \u3e 0.05) with carcass ultrasound measurements or with yearling weight. Exit velocity was negatively correlated (P = 0.04) with carcass weight (r = -0.65). Although, EV was not correlated (P \u3c 0.05) with carcass harvest traits of back fat and longissimus muscle area, results indicated more excitable cattle could have less back fat and smaller longissimus muscle area. Results suggest with additional numbers EV may be useful as an objective measure of temperament to sort calves into specific outcome groups that differ in carcass quality traits