Perceived Stress and the Buffering Hypothesis of Perceived Social Support on Facebook

Online social networking sites have experienced a surge in popularity since their inception. Serving as a hub for communities of all ages, Web sites such as MySpace, Friendster and Facebook bridge geographic and time limitations and offer their members the opportunity to connect with anyone on the Internet at any time. The growing accessibility of technology for computer-mediated communication, outside of such Web sites offers similar opportunities. Although critics share concern over potential for the loss of intimacy, the possibility for increased levels of perceived social support through limitless networking options should not be overlooked. When we consider the strong connection between perceived social support and perceived stress, which are linked to physical and mental symptomatology, the possible benefits are worthy of inquiry. This study explores the constructs of perceived social support and perceived stress and examines the impact of online social networking sites and computer-mediated communication upon a person’s experience of them. Results supported Cohen’s Stress-buffering hypothesis. A significant negative correlation was found for the association between reported levels of perceived social support and levels of perceived stress. Facebook use was not significantly related to perceived social support. This finding failed the second step for establishing mediation and disproved the hypothesis that perceived social support mediates a negative correlation between Facebook use and perceived stress. Further exploration revealed a significant relationship between respondent preference for computer-mediated communication, perceived social support, and perceived stress, however. The more that respondents preferred online communication to face-to-face or telephone communication, the greater the level of stress they perceived. Also, respondents who reported a preference for computer-mediated communication reported lower levels of perceived social support. A regression analysis was performed on these two relationships and perceived social support was found to mediate the relationship between a preference for computer-mediated communication and higher levels of perceived stress

Perceived Stress and the Buffering Hypothesis of Perceived Social Support on Facebook

Online social networking sites have experienced a surge in popularity since their inception. Serving as a hub for communities of all ages, Web sites such as MySpace, Friendster and Facebook bridge geographic and time limitations and offer their members the opportunity to connect with anyone on the Internet at any time. The growing accessibility of technology for computer-mediated communication, outside of such Web sites offers similar opportunities. Although critics share concern over potential for the loss of intimacy, the possibility for increased levels of perceived social support through limitless networking options should not be overlooked. When we consider the strong connection between perceived social support and perceived stress, which are linked to physical and mental symptomatology, the possible benefits are worthy of inquiry. This study explores the constructs of perceived social support and perceived stress and examines the impact of online social networking sites and computer-mediated communication upon a person’s experience of them. Results supported Cohen’s Stress-buffering hypothesis. A significant negative correlation was found for the association between reported levels of perceived social support and levels of perceived stress. Facebook use was not significantly related to perceived social support. This finding failed the second step for establishing mediation and disproved the hypothesis that perceived social support mediates a negative correlation between Facebook use and perceived stress. Further exploration revealed a significant relationship between respondent preference for computer-mediated communication, perceived social support, and perceived stress, however. The more that respondents preferred online communication to face-to-face or telephone communication, the greater the level of stress they perceived. Also, respondents who reported a preference for computer-mediated communication reported lower levels of perceived social support. A regression analysis was performed on these two relationships and perceived social support was found to mediate the relationship between a preference for computer-mediated communication and higher levels of perceived stress

Studies on growth rates in pigs and the effect of birth weight

End of project reportThe purpose of this study was to assess some environmental and management factors that affect growth performance on commercial pig units. In experiment 1, a survey was carried out on 22 pig units of known growth performance in south-west Ireland to compare management factors between those showing poor and good growth rates. Low growth rate appears to be due to the cumulative effect of a combination of factors. Experiment 2 was conducted to determine the effects of providing an additional feeder on performance of weaned piglets. No benefits were recorded. Feed consumed from the additional feeder was a replacement for feed that otherwise would have been consumed from the control hopper feeder. Experiment 3 was designed to determine if pig performance and efficiency of growth were affected by weight at birth and at weaning. Lightweight pigs showed inferior growth performance up to the finisher period. Although they compensated some of the inferior growth towards the time of slaughter, they never reached the weights of the heavy birth-weight animals. Males were either significantly heavier or tended to be heavier than females throughout. There was no significant difference between the sexes in the number of days to slaughter. Light and heavy pigs did not differ in the levels of IGF-1 in their blood plasma; however lightweight pigs had significantly lower IgG preweaning. Experiment 4 aimed to determine whether piglet birth weight influenced growth performance, plasma IGF-1 concentrations and muscle fibre characteristics at day 42 of life. At slaughter (Day 42) light birth weight pigs were significantly (P < 0.001) lighter. Plasma IGF-1 concentration was lower by 28% (P=0.06) in light pigs. Muscle fibre cross sectional area and total fibre number were not significantly different between groups. This study should be repeated with bigger numbers

Modeling inflammation and oxidative stress in gastrointestinal disease development using novel organotypic culture systems.

Gastroesophageal reflux disease (GERD), Barrett's esophagus (BE), graft-versus-host disease (GVHD), and inflammatory bowel diseases such as ulcerative colitis and Crohn's disease are common human gastrointestinal diseases that share inflammation as a key driver for their development. A general outcome resulting from these chronic inflammatory conditions is increased oxidative stress. Oxidative stress is caused by the generation of reactive oxygen and nitrogen species that are part of the normal inflammatory response, but are also capable of damaging cellular DNA, protein, and organelles. Damage to DNA can include DNA strand breaks, point mutations due to DNA adducts, as well as alterations in methylation patterns leading to activation of oncogenes or inactivation of tumor suppressors. There are a number of significant long-term consequences associated with chronic oxidative stress, most notably cancer. Infiltrating immune cells and stromal components of tissue including fibroblasts contribute to dynamic changes occurring in tissue related to disease development. Immune cells can potentiate oxidative stress, and fibroblasts have the capacity to contribute to advanced growth and proliferation of the epithelium and any resultant cancers. Disease models for GERD, BE, GVHD, and ulcerative colitis based on three-dimensional human cell and tissue culture systems that recapitulate in vivo growth and differentiation in inflammatory-associated microphysiological environments would enhance our understanding of disease progression and improve our ability to test for disease-prevention strategies. The development of physiologically relevant, human cell-based culture systems is therefore a major focus of our research. These novel models will be of enormous value, allowing us to test hypotheses and advance our understanding of these disorders, and will have a translational impact allowing us to more rapidly develop therapeutic and chemopreventive agents. In summary, this work to develop advanced human cell-based models of inflammatory conditions will greatly improve our ability to study, prevent, and treat GERD, BE, GVHD, and inflammatory bowel disease. The work will also foster the development of novel therapeutic and preventive strategies that will improve patient care for these important clinical conditions

Design and fabrication of highly efficient non-linear optical devices for implementing high-speed optical processing

We present the design and fabrication of micro-cavity semiconductor devices for enhanced Two-Photon-Absorption response, and demonstrate the use of these devices for implementing sensitive autocorrelation measurements on pico-second optical pulses

High-sensitivity two-photon absorption microcavity autocorrelator

A GaAs-AlAs microcavity device has been used as a photodetector in an autocorrelator for measuring the temporal pulsewidth of 1.5-/spl mu/m optical pulses. Enhancement of the two-photon absorption photocurrent due to the microcavity structure results in an autocorrelation (average power times peak power) sensitivity of 9.3/spl times/10/sup -4/ (mW)/sup 2/, which represents two orders of magnitude improvement when compared with conventional autocorrelators