Kolmogorov Complexity of Graphs

Kolmogorov complexity is a theory based on the premise that the complexity of a binary string can be measured by its compressibility; that is, a string’s complexity is the length of the shortest program that produces that string. We explore applications of this measure to graph theory

Effects of 5-HT2 receptor ligands on tail pinch-induced stress responding and open field behavior

Stress is known to exert an influence on neuroendocrine, autonomic, hormonal, and immune functioning. As a result of the debilitating effects of stress on numerous bodily systems, there exists a large body of research devoted to the etiology, physiological sequelae, and treatment of the condition. Further, the neurotransmitter serotonin (5-HT) has been implicated in stress responding. Presently, there is conflict in the literature as to the precise role serotonin plays in mediating the stress response. This study was an attempt to further elucidate the role of 5-HT in mediating an organism’s response to tail pinch stress and the open field. Previously, we have demonstrated that peripheral administration of the broad-spectrum 5-HT2 agonist, DOI, reduces stress responding in rats subjected to a tail pinch stressor (Hawkins, et al., 2002). This effect was fully blocked by peripheral coadministration of the broad spectrum 5-HT2 antagonist, ketanserin. The present study examined further the role of the 5-HT2 receptor subclass in mediating the stress response. We employed antagonists that selectively target either the 5-HT2A or 5-HT2C receptor in an effort to clarify the relative importance of each of these receptors in mediating the stress response. These compounds were injected subcutaneously in an effort to black the effects previously seen with DOI. DOI attenuated rearing and oral behavior directed at food, while increasing the frequency of head and body shakes in the open field. DOI-induced head shakes were blacked by the 5-HT2C antagonist, SDZ SER 082, as well as by a combination of SDZ SER 082 and the 5-HT2A antagonist, spiperone. Implications for the 5-HT2 receptor subclass in mediating stress responding are discussed

The digital environmental humanities (DEH) in the anthropocene: Challenges and opportunities in an era of ecological precarity

Researchers in the complementary fields of the digital humanities and the environmental humanities have begun to collaborate under the auspices of the digital environmental humanities (DEH). The overarching aim of this emerging field is to leverage digital technologies in understanding and addressing the urgencies of the Anthropocene. Emphasizing DEH’s focus on natural and cultural vitality, this article begins with a historical overview of the field. Crafting an account of the field’s emergence, we argue that the present momentum toward DEH exhibits four broad thematic strains including perennial eco-archiving; Anthropocene narratives of loss; citizen ecohumanities; and human-plant-environment relations. Within each of the four areas, the article identifies how DEH ideas have been implemented in significant projects that engage with, envision, re-imagine, and devise communities for environmental action and transformation. We conclude with suggestions for further bolstering DEH by democratizing environmental knowledge through open, community-engaged methods

Seasonal Diets of Newfoundland Martens, Martes americana atrata

We analyzed scats (n = 679) and stomach contents (n = 25) collected from 1980-2003 to assess the relative frequencies of food types utilized by Newfoundland Marten (Martes americana atrata) during summer and winter. Meadow Voles (Microtus pennsylvanicus) were the most prevalent food item occurring in 80% and 47.5% of samples from summer and winter, respectively. Apart from Snowshoe Hares (Lepus americana), which occurred in 28% of winter samples, all other food types occurred in <16% of samples during each season. Diet breadth was widest during winter and may be related to a lower availability of Meadow Voles during this time of year. Erratum included

Exploring pathways to gambling: Proposing the Integrated Risk and Protective Factors Model of Gambling Types

Three linked studies, testing key aspects of the Pathways towards Problem and Pathological Gambling Model (Blaszczynski & Nower, 2002), are presented. Study one comprised 204 students and 490 gambling forum users. It predicted differences in gambling severity, mental health and substance use across different motives for gambling. Those with a primary social motive for gambling displayed less severe gambling and anxiety than those without, with the primary coping subgroup displaying the most anxiety and depression. Those who gambled primarily to enhance positive affect reported severe gambling. Study two comprised 404 gambling forum users and 265 students. Similar groups to the Pathways Model emerged, with a behaviourally conditioned and an emotionally vulnerable group. Unexpectedly, however, those in the emotionally vulnerable group reported more severe cognitive distortions than the behaviourally conditioned group. The final study, 378 gambling forum users and 201 students found, as predicted, that three distinct gambling groups emerged; 1.) those with lower levels of psychopathology and higher levels of protective factors; 2.) those with heightened pre-existing anxiety and depression, and moderate levels of protective factors; and 3.) those with heightened impulsivity, psychopathology, offending behaviour and the least protective factors. Three gambling groups are consequently presented (Social Gambler; Affect-Regulation Gambler; Antisocial Gambler) alongside the proposed Integrated Risk and Protective Factors Model of Gambling Types (IRPF-MGT). Directions for future research and implications for practice are outlined

The impact of tensioning device mal-positioning on strand tension during Anterior Cruciate Ligament reconstruction

<p>Abstract</p> <p>Background</p> <p>In order to confer optimal strength and stiffness to the graft in Anterior Cruciate Ligament (ACL) reconstruction, the maintenance of equal strand tension prior to fixation, is desired; positioning of the tensioning device can significantly affect strand tension This study aimed to determine the effect of tensioning device mal-positioning on individual strand tension in simulated cadaveric ACL reconstructions.</p> <p>Methods</p> <p>Twenty cadaveric specimens, comprising bovine tibia and tendon harvested from sheep, were used to simulate ACL reconstruction with a looped four-strand tendon graft. A proprietary tensioning device was used to tension the graft during tibial component fixation with graft tension recorded using load cells. The effects of the tensioning device at extreme angles, and in various locking states, was evaluated.</p> <p>Results</p> <p>Strand tension varied significantly when the tensioning device was held at extreme angles (p < 0.001) or in 'locked' configurations of the tensioning device (p < 0.046). Tendon position also produced significant effects (p < 0.016) on the resultant strand tension.</p> <p>Conclusion</p> <p>An even distribution of tension among individual graft strands is obtained by maintaining the tensioning device in an unlocked state, aligned with the longitudinal axis of the tibial tunnel. If the maintenance of equal strand tension during tibial fixation of grafts is important, close attention must be paid to positioning of the tensioning device in order to optimize the resultant graft tension and, by implication, the strength and stiffness of the graft and ultimately, surgical outcome.</p