The Two-Pion Exchange NN-Potential in Nuclear Matter and Nuclear Stability

A meson exchange model of the $\pi\pi$ interaction which fits free $\pi\pi$ scattering data is used to calculate the interactions of pions in nuclear matter as a function of nuclear density. Polarization of the nuclear medium by the pions results in a marked increase in the s-wave $\pi\pi$ attraction at low energy. The influence of this effect on the nucleon-nucleon interaction is a corresponding increase with density of the $NN$ central potential due to the exchange of two correlated pions, resulting in an $NN$ interaction which fails to saturate. A possible mechanism for restoring the theoretical stability of nuclear matter is explored and found to be effective

Chirally Constraining the ππ\pi \pi Interaction in Nuclear Matter

A general prescription for the construction of $\pi \pi$ interaction potentials which preserve scattering length constraints from chiral symmetry when iterated in scattering equations is derived. The prescription involves only minor modifications of typical meson-exchange models, so that coupling constants and cut-off masses in the models are not greatly affected. Calculations of $s$-wave $\pi \pi$ scattering amplitudes in nuclear matter for two models are compared with those for similar models which violate the chiral constraint. While the prescription tends to suppress the accumulation of the near sub-threshold strength of the $\pi \pi$ interaction, an earlier conjecture that amplitudes which satisfy chiral constraints will not exhibit an instability towards $\pi \pi~s-$wave pair condensation appears to be incorrect. At the same time, however, conventional $\pi \pi$ interaction models which fit scattering data well can readily be adjusted to avoid the instability in nuclear matter without recourse to exotic mechanisms.Comment: 20 pages RevTeX and 5 figures (uuencoded .ps-files

Neural Coding and Synaptic Transmission: Participation Exercises for Introductory Psychology

We present two simulations of neural transmission for use in an Introductory Psychology class. These simulations illustrate the complex coding properties of a single neuron, especially how excitatory and inhibitory postsynaptic potentials accumulate to produce an action potential. A follow-up exercise, using the framework of the simple children's game Musical Chairs, illustrates synaptic transmission, including the effects of psychoactive drugs at the synapse.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

USING NONLINEAR FIXED AND MIXED MODELS WITH SWITCHING FUNCTIONS TO ALLOW FOR HORMESIS IN GROWTH OF ESCHERICHIA COLI

Individual Escherichia coli (E. coli) strains can be characterized by measuring growth rate. Strains better adapted to the environment are expected to grow faster. Classic bacterial growth curves display an increase in optical density over time. In this paper, we use the logistic function to model growth in optical density of E. coli over time. We examine 16 curves for 8 E. coli strains originally isolated from cattle and found many curves have a paradoxical dip at the beginning that is indicative of hormesis (an initial contrarian response showing, stimulation or suppression of growth). We examine several switching functions that allow for the effect of hormesis and compare the ability of nonlinear fixed and mixed models to detect the presence of hormesis

Nuclear Saturation with in-Medium Meson Exchange Interactions

We show that the assumption of dropping meson masses together with conventional many-body effects, implemented in the relativistic Dirac-Brueckner formalism, explains nuclear saturation. We use a microscopic model for correlated $2\pi$ exchange and include the standard many-body effects on the in-medium pion propagation, which initially increase the attractive nucleon-nucleon ($NN$) potential with density. For the vector meson exchanges in both the $\pi\pi$ and $NN$ sector, we assume Brown-Rho scaling which---in concert with `chiral' $\pi\pi$ contact interactions---reduces the attraction at higher densities.Comment: 5 pages REVTeX, 2 eps-figures included, submitted to Phys. Rev. Let

Power and persuasion: processes by which perceived power can influence evaluative judgments

This paper is not the copy of record and may not exactly replicate the authoritative document published in the APA journal. Please do not copy or cite without author's permission. The final article is available, upon publication, at: http://doi.org/10.1037/gpr0000119The present review focuses on how power—as a perception regarding the self, the source of the message, or the message itself—affects persuasion. Contemporary findings suggest that perceived power can increase or decrease persuasion depending on the circumstances and thus might result in both short-term and long-term consequences for behavior. Given that perceptions of power can produce different, and even opposite, effects on persuasion, it might seem that any relationship is possible and thus prediction is elusive or impossible. In contrast, the present review provides a unified perspective to understand and organize the psychological literature on the relationship between perceived power and persuasion. To accomplish this objective, present review identifies distinct mechanisms by which perceptions of power can influence persuasion and discusses when these mechanisms are likely to operate. In doing so, this article provides a structured approach for studying power and persuasion via antecedents, consequences, underlying psychological processes, and moderators. Finally, the article also discusses how power can affect evaluative judgments more broadl

Personalized Prediction of Future Lesion Activity and Treatment Effect in Multiple Sclerosis from Baseline MRI

Precision medicine for chronic diseases such as multiple sclerosis (MS) involves choosing a treatment which best balances efficacy and side effects/preferences for individual patients. Making this choice as early as possible is important, as delays in finding an effective therapy can lead to irreversible disability accrual. To this end, we present the first deep neural network model for individualized treatment decisions from baseline magnetic resonance imaging (MRI) (with clinical information if available) for MS patients. Our model (a) predicts future new and enlarging T2 weighted (NE-T2) lesion counts on follow-up MRI on multiple treatments and (b) estimates the conditional average treatment effect (CATE), as defined by the predicted future suppression of NE-T2 lesions, between different treatment options relative to placebo. Our model is validated on a proprietary federated dataset of 1817 multi-sequence MRIs acquired from MS patients during four multi-centre randomized clinical trials. Our framework achieves high average precision in the binarized regression of future NE-T2 lesions on five different treatments, identifies heterogeneous treatment effects, and provides a personalized treatment recommendation that accounts for treatment-associated risk (e.g. side effects, patient preference, administration difficulties).Comment: Accepted to MIDL 202

Environmental Parameters Associated With Stable Fly (Diptera: Muscidae) Development at Hay Feeding Sites

Substrates composed of hay residues, dung, and urine accumulate around winter hay feeding sites in cattle pastures, providing developmental habitats for stable flies. The objective of this study was to relate physiochemical and microbial properties of these substrates to the presence or absence of stable fly larvae. Properties included pH, temperature, moisture, ammonium concentration, electrical conductivity, and numbers of coliform, fecal coliform, Escherichia coli, and Enterococcus bacteria. Each physiochemical sample was classified as a function of belonging to one of the three 2-m concentric zones radiating from the feeder as well as presence or absence of larvae. In total, 538 samples were collected from 13 sites during 2005–2011. Stable fly larvae were most likely to be found in moist, slightly alkaline substrates with high levels of ammonium and low temperature. The probability of larvae being present in a sample was the highest when the moisture content was 347% relative to dry weight and the average pH was 8.4. Larvae were recovered within all zones, with a nonsignificant, but slightly higher, percentage of samples containing larvae taken 2–4m from the center. All methods used to enumerate bacteria, except total coliform, indicated decreasing concentrations in hay bale residue throughout the summer. In addition to the environmental parameters, cumulative degree day 10˚C had a significant effect on the probability of observing stable fly larvae in a sample, indicating that unidentified seasonal effects also influenced immature stable fly populations

Environmental Parameters Associated With Stable Fly (Diptera: Muscidae) Development at Hay Feeding Sites

Substrates composed of hay residues, dung, and urine accumulate around winter hay feeding sites in cattle pastures, providing developmental habitats for stable flies. The objective of this study was to relate physiochemical and microbial properties of these substrates to the presence or absence of stable fly larvae. Properties included pH, temperature, moisture, ammonium concentration, electrical conductivity, and numbers of coliform, fecal coliform, Escherichia coli, and Enterococcus bacteria. Each physiochemical sample was classified as a function of belonging to one of the three 2-m concentric zones radiating from the feeder as well as presence or absence of larvae. In total, 538 samples were collected from 13 sites during 2005–2011. Stable fly larvae were most likely to be found in moist, slightly alkaline substrates with high levels of ammonium and low temperature. The probability of larvae being present in a sample was the highest when the moisture content was 347% relative to dry weight and the average pH was 8.4. Larvae were recovered within all zones, with a nonsignificant, but slightly higher, percentage of samples containing larvae taken 2–4m from the center. All methods used to enumerate bacteria, except total coliform, indicated decreasing concentrations in hay bale residue throughout the summer. In addition to the environmental parameters, cumulative degree day 10˚C had a significant effect on the probability of observing stable fly larvae in a sample, indicating that unidentified seasonal effects also influenced immature stable fly populations