A Novel Mixed-Extinction Paradigm Makes Extinguished Pavlovian Associations More Resistant to Behavioural Relapse

Omission and Overexpectation are two paradigms that lead to a reduction in the associative relationship between events. In Omission, this is achieved through absence of the delivery of an expected outcome. In Overexpectation, two individually trained cues are presented together and are met with an outcome of less intensity then the sum of the two expected outcomes. The reduction in the conditioned response following Omission or Overexpectation training reflects a reduction in the associative relationship between the target cue and the conditioned response. However, this reduction is easily disrupted. Testing outside of the extinction context, letting time pass, or giving unsignalled exposure to the unconditioned stimulus, each lead to an increase in the conditioned response from extinction levels. These effects can be explained by a view that the original association is not erased but rather is inhibited by extinction learning and this extinction learning is more vulnerable to disruption. Insight in to this disruption might come from a biological perspective where Omission and Overexpectation have been tracked by unique and overlapping neuronal populations in the central nucleus of the amygdala (Iordanova et al., 2016). Given evidence that unique and overlapping neuronal populations are involved, one might expect the influence of two these processes to be behaviourally additive. This raises the possibility that targeting the unique and common populations associated with Omission and Overexpectation through combining both forms of extinction training might lead to lasting reduction in behaviour as one that is more resistance to relapse. To test this prediction, following conditioning of two different cues with a positive reinforcement, Sprague Dawley rats (Rattus norvegicus) were assigned to either a constantly reinforced Control, an Overexpectation-only, Omission-only, or a Mixed group consisting of blocks of Overexpectation sessions followed by blocks of Omission sessions. Subsequent Renewal, and Reinstatement tests show higher responding in the Control group compared to the three groups that had undergone extinction or Overexpectation training, with the Mixed extinction group showing the lowest rate of response. This effect was consistent across different dependant variables. However a Spontaneous Recovery test, though yielding a similar decrease, did not result in a substantive effect-size statistic or a statistically significant null hypothesis test. Taken together these findings have potential implications for deepening reductions of maladaptive associations on behaviour, such as those present in addiction and anxiety disorders

Economic inequality increases risk taking

Income inequality is rising around the world. Increased income inequality has been linked with higher rates of crime, greater debt, and poorer health, but the mechanisms linking inequality to poor outcomes among individuals are poorly understood. This research tested a behavioral account linking inequality to individual decision making. The account suggests that more unequal outcomes lead people to perceive that they need more resources to be satisfied. Higher perceived needs, in turn, motivate greater risk taking to meet those needs. Results of three experiments and an analysis of large-scale internet search data supported the proposed account. Results suggest that inequality may promote a range of poor outcomes, in part, by increasing risky behavior

The 55 Cancri Planetary System: Fully Self-Consistent N-body Constraints and a Dynamical Analysis

We present an updated study of the planets known to orbit 55 Cancri A using 1,418 high-precision radial velocity observations from four observatories (Lick, Keck, Hobby-Eberly Telescope, Harlan J. Smith Telescope) and transit time/durations for the inner-most planet, 55 Cancri "e" (Winn et al. 2011). We provide the first posterior sample for the masses and orbital parameters based on self-consistent n-body orbital solutions for the 55 Cancri planets, all of which are dynamically stable (for at least $10^8$ years). We apply a GPU version of Radial velocity Using N-body Differential evolution Markov Chain Monte Carlo (RUN DMC; B. Nelson et al. 2014) to perform a Bayesian analysis of the radial velocity and transit observations. Each of the planets in this remarkable system has unique characteristics. Our investigation of high-cadence radial velocities and priors based on space-based photometry yields an updated mass estimate for planet "e" ($8.09\pm0.26$ M$_\oplus$), which affects its density ($5.51\pm^{1.32}_{1.00}$ g cm$^{-3}$) and inferred bulk composition. Dynamical stability dictates that the orbital plane of planet "e" must be aligned to within $60^o$ of the orbital plane of the outer planets (which we assume to be coplanar). The mutual interactions between the planets "b" and "c" may develop an apsidal lock about $180^o$. We find 36-45% of all our model systems librate about the anti-aligned configuration with an amplitude of $51^o\pm^{6^o}_{10^o}$. Other cases showed short-term perturbations in the libration of $\varpi_b-\varpi_c$, circulation, and nodding, but we find the planets are not in a 3:1 mean-motion resonance. A revised orbital period and eccentricity for planet "d" pushes it further toward the closest known Jupiter analog in the exoplanet population.Comment: 12 pages, 5 figures, 4 tables, accepted to MNRAS. Figure 2 (left) is updated from published version. Posterior samples available at http://www.personal.psu.edu/ben125/Downloads.htm

A Quantum Space behind Simple Quantum Mechanics

In physics, experiments ultimately inform us about what constitutes a good theoretical model of any physical concept: physical space should be no exception. The best picture of physical space in Newtonian physics is given by the configuration space of a free particle (or the center of mass of a closed system of particles). This configuration space (as well as phase space) can be constructed as a representation space for the relativity symmetry. From the corresponding quantum symmetry, we illustrate the construction of a quantum configuration space, similar to that of quantum phase space, and recover the classical picture as an approximation through a contraction of the (relativity) symmetry and its representations. The quantum Hilbert space reduces into a sum of one-dimensional representations for the observable algebra, with the only admissible states given by coherent states and position eigenstates for the phase and configuration space pictures, respectively. This analysis, founded firmly on known physics, provides a quantum picture of physical space beyond that of a finite-dimensional manifold and provides a crucial first link for any theoretical model of quantum space-time at levels beyond simple quantum mechanics. It also suggests looking at quantum physics from a different perspective

Examining a Peak-Luminosity/Decline-Rate Relationship for Tidal Disruption Events

We compare the luminosity, radius, and temperature evolution of the UV/optical blackbodies for 21 well-observed tidal disruption events (TDEs), 8 of which were discovered by the All-Sky Automated Survey for Supernovae. We find that the blackbody radii generally increase prior to peak and slowly decline at late times. The blackbody temperature evolution is generally flat, with a few objects showing small-scale variations. The bolometric UV/optical luminosities generally evolve smoothly and flatten out at late times. Finally, we find an apparent correlation between the peak luminosity and the decline rate of TDEs. This relationship is strongest when comparing the peak luminosity to its decline over 40 days. A linear fit yields $\log_{10}( L_{peak}) = (44.1^{+0.1}_{-0.1}) + (1.6^{+0.4}_{-0.2})(\Delta L_{40} + 0.5)$ in cgs, where $\Delta L_{40} = \log_{10}(L_{40} / L_{peak})$.Comment: 10 pages, 4 figures. Updated to reflect changes made in the published ApJL version. Six new objects added to sample. Updated video description can be found at https://youtu.be/TtZU22eyHv

Revealing AGNs Through TESS Variability

We used Transiting Exoplanet Survey Satellite (TESS) data to identify 29 candidate active galactic nuclei (AGNs) through their optical variability. The high-cadence, high-precision TESS light curves present a unique opportunity for the identification of AGNs, including those not selected through other methods. Of the candidates, we found that 18 have either previously been identified as AGNs in the literature or could have been selected based on emission-line diagnostics, mid-IR colors, or X-ray luminosity. AGNs in low-mass galaxies offer a window into supermassive black hole (SMBH) and galaxy co-evolution and 8 of the 29 candidates have estimated black hole masses $\mathrm{\lesssim 10^{6} M_{\odot}}$. The low-mass galaxies NGC 4395 and NGC 4449 are two of our five "high-confidence" candidates. By applying our methodology to the entire TESS main and extended mission datasets, we expect to identify $\sim$45 more AGN candidates, of which $\sim$26 will be new and $\sim$8 will be in low-mass galaxies.Comment: 21 pages, 17 figures, 6 tables. Will be submitted to AAS journals. Comments welcom