817 research outputs found
Digit Ratio (2D:4D): A Biomarker for Prenatal Sex Steroids and Adult Sex Steroids in Challenge Situations
No full textDigit ratio (2D:4D) denotes the relative length of the second and fourth digits. This ratio is considered to be a biomarker of the balance between fetal testosterone (T) and estrogen (E) in a narrow window of early ontogeny. Evidence for this assertion is derived from direct and indirect measures of prenatal hormonal exposure (in experimental animals, via amniotic fluid samples and in the study of sex-typical traits) in relation to 2D:4D. In contrast, the relationships between 2D:4D and levels of sex steroids in adults are less clear, as many correlational studies of 2D:4D and adult sex steroids have concluded that this association is statistically non-significant. Here, we suggest that in order to understand the link between 2D:4D and sex hormones, one must consider both fetal organizing and adult activating effects of T and E. In particular, we hypothesize that 2D:4D correlates with organizing effects on the endocrine system that moderate activating effects in adulthood. We argue that this is particularly evident in “challenging” conditions such as aggressive and sexual encounters, in which individuals show increased levels of T. We discuss this refinement of the 2D:4D paradigm in relation to the links between 2D:4D and sports performance, and aggression
Liam Rector, 14th Annual ODU Literary Festival
No full textLiam Rector is the author of The Sorrow of Architecture, a book of poems. He\u27s also the editor of The Day I Was Older: On the Poetry of Donald Hall. He has taught at Old Dominion University, George Mason, Goucher College, and Phillips Academy at Andover. In addition, he has administered literary programs at the Folger Academy of American Poets. Currently, Liam Rector is executive director of Associated Writing Programs, which has lately taken a leading role in defending the 1st amendment. Rector has been awarded both NEA and Guggenheim fellowships for poetry
Liam Rector, 12th Annual ODU Literary Festival
No full textLiam Rector is the author of a book of poetry, The Sorrow of Architecture, 1984, and editor of The Day I Was Older: On the Poetry of Donald Hall, 1989, and is currently working on a second book of poems, tentatively titled The Persistence of Virginia. He is executive director of the Associated Writing Programs, located at Old Dominion University
Project Triton : A study into delivering targeted information to an individual based on implicit and explicit data.
No full textThe World Wide Web is frequently seen as a source of knowledge, however much of this remains undiscovered by its users. In recent times, recommender systems (e.g. Digg and Last.fm) have attempted to bridge this gap, alerting users to previously untapped knowledge. As more socially oriented services appear on the Web (e.g. Facebook and MySpace), it has never been easier to obtain information pertaining to an individual’s interests. At present, solutions for automated data recommendation tend to be highly topic specific (recommending only a certain topic such as news) and often only allow access to the system using monolithic interfaces. This report hopes to detail the stages from research to evaluation involved in creating an extensible framework, which will operate without the need for human intervention. The framework will feature several proof-of-concept plugins residing in a custom workflow, which target information that is useful to the user. Information will be retrieved automatically through plugins involved with data gathering (such as feed processing and page scraping), while users’ interests will be obtained implicitly (for example, using header information to derive location) or explicitly (taking advantage of Social Network APIs such as Facebook Connect). Finally, Third Parties will be able to integrate the framework into their own solutions using the customisable XML API (written in PHP), so that their products can provide custom user interfaces without style constraints
Brain serotonin and dopamine modulators, perceptual responses and endurance performance during exercise in the heat following creatine supplementation
No full textBackground:The present experiment examined the responses of peripheral modulators and indices of brain serotonin (5-HT) and dopamine (DA) function and their association with perception of effort during prolonged exercise in the heat after creatine (Cr) supplementation. Methods:Twenty one endurance-trained males performed, in a double-blind fashion, two constant-load exercise tests to exhaustion at 63 ± 5% V O2 max in the heat (ambient temperature: 30.3 ± 0.5°C, relative humidity: 70 ± 2%) before and after 7 days of Cr (20 g·d-1 Cr + 140 g·d-1 glucose polymer) or placebo (Plc) (160 g·d-1 glucose polymer) supplementation.Results:3-way interaction has shown that Cr supplementation reduced rectal temperature, heart rate, ratings of perceived leg fatigue (P < 0.05), plasma free-tryptophan (Trp) (P < 0.01) and free-Trp:tyrosine ratio (P < 0.01) but did not influence the ratio of free-Trp:large neutral amino acids or contribute in improving endurance performance (Plc group, n = 10: 50.4 ± 8.4 min vs. 51.2 ± 8.0 min, P > 0.05; Cr group, n = 11: 47.0 ± 4.7 min vs. 49.7 ± 7.5 min, P > 0.05). However, after dividing the participants into "responders" and "non-responders" to Cr, based on their intramuscular Cr uptake, performance was higher in the "responders" relative to "non-responders" group (51.7 ± 7.4 min vs.47.3 ± 4.9 min, p < 0.05).Conclusion:although Cr influenced key modulators of brain 5-HT and DA function and reduced various thermophysiological parameters which all may have contributed to the reduced effort perception during exercise in the heat, performance was improved only in the "responders" to Cr supplementation. The present results may also suggest the demanding of the pre-experimental identification of the participants into "responders" and "non-responders" to Cr supplementation before performing the main experimentation. Otherwise, the possibility of the type II error may be enhance
Design, fabrication and molecular modeling of protein subunits for use in a novel hydrogel:
No full textUse of bioinspired, genetically engineered proteins in tissue engineering scaffolds represents a new opportunity for engineering these constructs. However, the production and rational modification of new, artificial proteins is hindered by significant gaps in knowledge regarding expression of artificial gene constructs in E. coli and their molecular modeling. This thesis focuses on the production of a novel hydrogel scaffold composed of four self-assembling protein modules and their rational modification using Molecular Dynamics (MD) simulations. Two of the modules are based on the ABA triblock copolymer design. In this triblock, a hydrophilic, random coiled region is flanked by 28 amino-acid α−helical endblocks. The purpose of these endblocks is to function as virtual crosslinkers and support network formation. The length of the endblocks can be changed by the addition of two unlinked, fiber-forming peptides and thus potentially alter the gelation and melting points of the hydrogel. We evaluate the efficacy of production of these endblocks by two separate expression strategies in E. coli and demonstrate their ability to form hydrogels. Furthermore, we analyze the Gibbs free energy of formation of oligomeric intermediates that arise early on during fibrillogenesis from the unlinked peptides using the MM/PBSA module of Amber 9. Thermodynamic data demonstrates changes in the primary structure of these peptides affect the stability of the intermediate that seeds fiber formation. This analysis also suggests a shift in the fiber forming mechanism from monomer addition to protofibril addition. We offer how this data can be used to improve interhelical interactions between endblocks and unlinked peptides and how to develop coarse-grain models of fiber formation.Ph.D.Includes bibliographical referencesby Christopher Liam Gaugha
Match play performance characteristics that predict post-match creatine kinase responses in professional rugby union players
No full textBackground: Rugby union players can take several days to fully recover from competition. Muscle damage induced during the match has a major role in player recovery; however the specific characteristics of match play that predict post-match muscle damage remains unclear. We examined the relationships between a marker of muscle damage and performance characteristics associated with physical contacts and high-speed movement in professional rugby union players.
Methods: Twenty-eight professional rugby union players (15 forwards, 13 backs) participated in this study. Data were obtained from 4 European Cup games, with blood samples collected 2 h pre, and 16 and 40 h post-match, and were subsequently analysed for creatine kinase (CK). Relationships between changes in CK concentrations and number of physical contacts and high-speed running markers, derived from performance analysis and global positioning system (GPS) data, were assessed.
Results: Moderate and moderate-large effect-size correlations were identified between contact statistics from performance analysis and changes in CK at 16 and 40 h post match in forwards and backs, respectively (e.g. backs; total impacts vs. ΔCK (r = 0.638, p < 0.01) and Δ% CK (r = 0.454, p < 0.05) 40 h post-match). Furthermore, moderate effect-size correlations were found between measures of high-speed running and sprinting, and changes in CK at 16 and 40 h post-match within the backs (e.g. high-speed running distance vs. ΔCK (r = 0.434, p = 0.056) and Δ% CK (r = 0.437, p = 0.054) 40 hrs post-match).
Conclusions: Our data demonstrate that muscle damage induced by professional rugby union match play is to some extent predicted by the number of physical contacts induced during performance. Furthermore, we show for the first time that muscle damage in backs players is predicted by high-speed running measures derived from GPS. These data increase the understanding of the causes of muscle damage in rugby union; performance markers could potentially be used to tailor individual recovery strategies and subsequent training following rugby union competition
Poor levels of agreement between serum and saliva testosterone measurement following exercise training in aging men
No full textBetween-Match Variability of Peak Power Output and Creatine Kinase Responses to Soccer Match-Play
No full textTrained and untrained males show reliable salivary testosterone responses to a physical stimulus, but not a psychological stimulus
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