Orbital Variability in the Eclipsing Pulsar Binary PSR B1957+20

We have conducted timing observations of the eclipsing millisecond binary pulsar PSR~B1957+20, extending the span of data on this pulsar to more than five years. During this time the orbital period of the system has varied by roughly $\Delta P_b/P_b = 1.6 \times 10^{-7}$, changing quadratically with time and displaying an orbital period second derivative $\ddot P_b = (1.43 \pm 0.08) \times 10^{-18}\,$s$^{-1}$. The previous measurement of a large negative orbital period derivative reflected only the short-term behavior of the system during the early observations; the orbital period derivative is now positive and increasing rapidly. If, as we suspect, the PSR~B1957+20 system is undergoing quasi-cyclic orbital period variations similar to those found in other close binaries such as Algol and RS CVn, then the $0.025\,M{_\odot}$ companion to PSR~B1957+20 is most likely non-degenerate, convective, and magnetically active.Comment: 9 pages, 3 figures, LaTeX, submitted ApJL 13 Dec. 1993, arz-00

A sore red eye with systemic involvement

The study of happiness has long been a playground for philosophical speculation. By lack of empirical measures of happiness, it was not possible to check propositions about the matter. In the late 20th century, survey-research methods introduced by the social sciences have brought a break-through. Dependable measures of happiness have developed, by means of which a significant body of knowledge has evolved

A Spectacle and Nothing Strange

Working through methods of abstraction and comedic mimicry I choreograph awkwardly balanced sculpture with objects of adornment as a means to defuse personal sensitivities surrounding my experiences of gender, desire, and home. The research that follows is concerned with the adjacent, the in between, above and underneath, because I feel that this kind of looking means that you are, to some degree, aware of what lies at the edges. Maybe this is what Gertrude Stein means to act as though there is no use in a center—because this concerns a way of relating, though there are many things in the room. ‘A spectacle and nothing strange’ is an arrangement of gestures, of made difference, of kinships, of orientations and possible futures, sustained tension, coded adornment, big dyke energy, shifts in hardness, leaning softness, much more than flowers, ...and in any case there is sweetness and some of that

Attachment Styles as Moderator Between Stress and Emotional Eating in Adolescent Girls: A Research Proposal

Emotional eating is an important precursor of weight gain and obesity among adolescent girls (Halberstadt et al., 2016). Researchers have defined emotional eating as individuals’ eating behaviors in response to the positive or negative emotions they endure (Bongers & Jansen, 2016). In past studies, stress has been found to be an important indicator of emotional eating in adolescent girls (Corsica, Hood, Katterman, Kleinman, & Ivan, 2014). However, not all girls who experience stress will engage in emotional eating. The stress-diathesis model suggests that certain traits of vulnerability may predispose some individuals towards mental health problems (e.g., eating disorders) in response to stress (MacNeil, Esposito-Smythers, Mehlenbeck, & Weismore, 2012). One of the important traits that may moderate the effect of stress on mental health problems is attachment styles (Chow & Ruhl, 2014). Attachment styles are defined as the internalized mental representations of individuals’ key attachment figures (e.g., mothers; Cooper, Shaver, & Collins, 1998). Attachment styles are measured by the dimensions of anxiety (e.g., fear of being abandoned by others) and avoidance (e.g., fear of being too close to others). Combining the stress-diathesis model and attachment theory, the current study aims to investigate whether adolescent girls’ attachment security within close relationships moderates the link between experiences of stress and emotional eating. Specifically, it is hypothesized that girls who are low in attachment security engage in more emotional eating when under stress. In contrast, it is hypothesized that girls who are high in attachment security engage in less emotional eating, regardless of their stress levels. To test the hypothesis, data will be drawn from archival data including 100 adolescent girls between 11 and 18 years old. Participants answered questionnaires on stress attachment security to their parents and whether they engaged in emotional eating. Moderation hypothesis will be examined with multiple regression implemented in R

Identification of criticality in neuronal avalanches: II. A theoretical and empirical investigation of the Driven case

The observation of apparent power laws in neuronal systems has led to the suggestion that the brain is at, or close to, a critical state and may be a self-organised critical system. Within the framework of self-organised criticality a separation of timescales is thought to be crucial for the observation of power-law dynamics and computational models are often constructed with this property. However, this is not necessarily a characteristic of physiological neural networks—external input does not only occur when the network is at rest/a steady state. In this paper we study a simple neuronal network model driven by a continuous external input (i.e. the model does not have an explicit separation of timescales from seeding the system only when in the quiescent state) and analytically tuned to operate in the region of a critical state (it reaches the critical regime exactly in the absence of input—the case studied in the companion paper to this article). The system displays avalanche dynamics in the form of cascades of neuronal firing separated by periods of silence. We observe partial scale-free behaviour in the distribution of avalanche size for low levels of external input. We analytically derive the distributions of waiting times and investigate their temporal behaviour in relation to different levels of external input, showing that the system’s dynamics can exhibit partial long-range temporal correlations. We further show that as the system approaches the critical state by two alternative ‘routes’, different markers of criticality (partial scale-free behaviour and long-range temporal correlations) are displayed. This suggests that signatures of criticality exhibited by a particular system in close proximity to a critical state are dependent on the region in parameter space at which the system (currently) resides

Identification of criticality in neuronal avalanches: I. A theoretical investigation of the non-driven case

In this paper, we study a simple model of a purely excitatory neural network that, by construction, operates at a critical point. This model allows us to consider various markers of criticality and illustrate how they should perform in a finite-size system. By calculating the exact distribution of avalanche sizes, we are able to show that, over a limited range of avalanche sizes which we precisely identify, the distribution has scale free properties but is not a power law. This suggests that it would be inappropriate to dismiss a system as not being critical purely based on an inability to rigorously fit a power law distribution as has been recently advocated. In assessing whether a system, especially a finite-size one, is critical it is thus important to consider other possible markers. We illustrate one of these by showing the divergence of susceptibility as the critical point of the system is approached. Finally, we provide evidence that power laws may underlie other observables of the system that may be more amenable to robust experimental assessment