Mixed mode oscillations in a conceptual climate model

Much work has been done on relaxation oscillations and other simple oscillators in conceptual climate models. However, the oscillatory patterns in climate data are often more complicated than what can be described by such mechanisms. This paper examines complex oscillatory behavior in climate data through the lens of mixed-mode oscillations. As a case study, a conceptual climate model with governing equations for global mean temperature, atmospheric carbon, and oceanic carbon is analyzed. The nondimensionalized model is a fast/slow system with one fast variable (corresponding to ice volume) and two slow variables (corresponding to the two carbon stores). Geometric singular perturbation theory is used to demonstrate the existence of a folded node singularity. A parameter regime is found in which (singular) trajectories that pass through the folded node are returned to the singular funnel in the limiting case where $\epsilon = 0$. In this parameter regime, the model has a stable periodic orbit of type $1^s$ for some $s>0$. To our knowledge, it is the first conceptual climate model demonstrated to have the capability to produce an MMO pattern.Comment: 28 pages, 11 figure

Electrophysiological responses to alcohol cues are not associated with Pavlovian-to-Instrumental Transfer in social drinkers

Peer reviewedPublisher PD

Help-Seeking Attitudes of Gay and Bisexual Men Who Suffer From Eating Disorders

Eating disorders have long been associated primarily with, and studied in, heterosexual women, however, multiple studies have found that the frequency of eating disorders in gay and bisexual men is nearly as prevalent. It has been found that heterosexual women are more likely to seek help than heterosexual men. The purpose of our study will be to explore the prevalence of help-seeking attitudes among gay and bisexual men. Two scales: Beliefs About Psychological Services and Body Parts Satisfaction will be administered by a convenience sample of homosexual and bisexual university students from a various geographical locations within the U.S

Paper Session III-A - The Mobile Servicing System - A System Description

This paper is a systems description of the Mobile Servicing System (MSS) to be provided by Canada, an International Partner to the NASA Space Station Freedom. The paper desf nbes space segment, ground segment, and support systems. Spar is the prime contractor to the National Research Council of Canada (NRCC). The MSS will provide the functional capabilities for Space Station Freedom construction, maintenance, deployment, and retrieval of Free Flying Spacecraft and servicing of attached payloads

Direct evidence of an efficient energy transfer pathway from jellyfish carcasses to a commercially important deep-water species

Here we provide empirical evidence of the presence of an energetic pathway between jellyfish and a commercially important invertebrate species. Evidence of scavenging on jellyfish carcasses by the Norway lobster (Nephrops norvegicus) was captured during two deployments of an underwater camera system to 250–287 m depth in Sognefjorden, western Norway. The camera system was baited with two Periphylla periphylla (Scyphozoa) carcasses to simulate the transport of jellyfish detritus to the seafloor, hereby known as jelly-falls. N. norveigus rapidly located and consumed a large proportion (>50%) of the bait. We estimate that the energy input from jelly-falls may represent a significant contribution to N. norvegicus energy demand (0.21 to 10.7 times the energy required for the population of N. norvegicus in Sognefjorden). This potentially high energetic contribution from jelly-falls highlights a possible role of gelatinous material in the support of commercial fisheries. Such an energetic pathway between jelly-falls and N. norvegicus could become more important with increases in jellyfish blooms in some regions

Alcohol-induced risk taking on the BART mediates alcohol priming

Rationale Hazardous drinking has been associated with risk taking and alcohol priming effects. However, the potential relationship between risk taking and priming has not been investigated. The Balloon Analogue Risk Task (BART) is a behavioural measure of risk taking which appears to be associated with drinking behaviour. However, alcohol's acute effects on BART performance are not clear, and the potentially mediating effect of alcohol-induced risk taking on priming has not been tested. Objectives To assess the effects of a priming dose of alcohol on BART performance; to determine the predictive utility of the BART on drinking habits; and to identify whether alcohol-induced risk taking mediates alcohol priming (urge to drink). Methods A total of 142 participants provided data on drinking habits and trait-like impulsivity and sensation seeking. The BART was then completed after consuming alcohol (0.6 g/kg) or placebo (between-subjects design). Baseline and post-drink measures of alcohol urge were also taken. Results Alcohol consumption increased urge to drink (priming) and risk taking on the BART. In the alcohol group only, risk taking on the BART predicted unique variance in weekly alcohol consumption and bingeing. Mediation analysis showed that risk taking following alcohol consumption mediated alcohol priming. Conclusions This is the first study to show that alcohol acutely increases risk taking on the BART. Results suggest that social drinkers susceptible to alcohol-induced risk taking may be more likely to drink excessively, perhaps due to increased urge to drink (priming)

A Model of the kraft recovery furnace

Ph.D