Social self-preservation theory (SSPT) suggests that when faced with social-evaluative threat, a set of psychological and physiological responses are elicited concurrently (Dickerson, Gruenewald, & Kemeny, 2004; Kemeny, Gruenewald, & Dickerson, 2004). A series of studies examined the applicability of SSPT to the examination of social-evaluative body-related threats. In the first study, interviews were conducted to identify and describe uncomfortable body-related situations, and typical responses to such situations. Findings provided preliminary evidence of the applicability of SSPT to everyday body-related threats of young adult women – the threats, context of those threats, and responses to such threats were consistent with SSPT. The second study examined psychobiological responses to, and recovery from, a social-evaluative body-related threat. Findings from this study showed that the social-evaluative body-related threat elicited a psychobiological response consistent with SSPT; women in the threat group reported higher social physique anxiety and had higher cortisol following the threat. The third study sought to extend the applicability of SSPT to examine the psychobiological responses to, and recovery from, an anticipated social-evaluative body-related threat. In addition, the potential moderating effect of appearance investment on responses to a threat was examined. Findings from this study showed that women in the threat group reported higher shame and social physique anxiety after anticipating a social-evaluative body-related threat than following a quiet rest period for women in the control group. Results also indicated that both groups showed an index of decrease for cortisol, with the control group showing a significantly greater overall decrease than the threat group. Appearance investment did not moderate cortisol responses to a threat. Findings from the third study provide partial support for SSPT’s applicability to the anticipation of a social-evaluative body-related threat. Together findings from all three studies provide converging evidence for the use of SSPT in understanding the psychobiology of body image.

The combined effect of various gas packaging atmospheres (air, vacuum and gas packaging), films of different oxygen transmission rate (OTR) and storage temperature (4 and 12°C) were investigated on the shelf-life and safety of flesh rainbow trout fillets. / Preliminary studies were done to determine the optimum packaging atmospheres to maintain the bright pink color of trout packaged in a high gas barrier film. Both vacuum and gas packaging (85% CO2:15%N2) resulted in the longest shelf-life (~28 days) in terms of color at 4°C. Based on these optimum gas atmospheres for color, shelf-life studies were performed at both refrigerated and temperature abuse conditions (12°C). / Challenges studies were also done with Listeria monocytogenes and Clostridium botulinum type E, two psychrotrophic pathogens of concern in modified atmosphere packaged (MAP) fish. / Subsequent studies were done to determine the effect of various levels of headspace oxygen (0--100%, balance CO2) or film OTR on the time to toxicity in trout stored at 12°C. (Abstract shortened by UMI.)

Value-added trout burgers and trout wontons were prepared from minced trout trimmings, oats, dried onion flakes, white pepper, cayenne pepper, garlic powder, soy sauce, spice mix and eggs. The trout burgers were coated with crushed cornflakes and then partially cooked (2 min at 140ºC) or frilly cooked (5 min at 140ºC) in hot oil. Similar fillings were used to prepare trout wontons by wrapping the mixture with Chinese wonton dough and 2 products were made: raw wonton (uncooked) and fried wonton (fried for 8 min at 140ºC). / Storage trials were performed on raw and fried trout wontons (a w 0.98--0.95, pH 6.5), and partially and fully cooked trout burgers (aw 0.97--0.96, pH 6.4). Products were packaged in air and under various modified atmospheres (MAP), and stored at 4 and 12ºC. A microbiological shelf-life of >28 days was possible for the cooked trout burgers and fried wontons stored at 4ºC. In general, the microbiological shelf-life preceded the sensory shelf-life. / Subsequent challenge studies were done to address the safety concerns associated with MAP food. All products were inoculated with 102 CFU/g of Listeria monocytogenes and 102 spores/g of Clostridium botulinum type E spores. Gas packaging with 80% CO2 (balance N2) inhibited the growth of L. monocytogenes in products stored at 4ºC. However, counts of L. monocytogenes increased in all other packaging conditions. In challenge studies with C. botulinum type E, toxin was not detected in any products after 28--60 days.

Improving road safety and traffic efficiency has been a long-term endeavor for the government, automobile industry and academia. Recently, the U.S. Federal Communication Commission (FCC) has allocated a 75 MHz spectrum at 5.9 GHz for vehicular communications, opening a new door to combat the road fatalities by letting vehicles communicate to each other on the roads. Those communicating vehicles form a huge Ad Hoc Network, namely Vehicular Ad Hoc Network (VANET). In VANETs, a variety of applications ranging from the safety related (e.g. emergence report, collision warning) to the non-safety related (e.g., delay tolerant network, infortainment sharing) are enabled by vehicle-to-vehicle (V-2-V) and vehicle-to-roadside (V-2-I) communications. However, the flourish of VANETs still hinges on fully understanding and managing the challenging issues over which the public show concern, particularly, security and privacy preservation issues. If the traffic related messages are not authenticated and integrity-protected in VANETs, a single bogus and/or malicious message can potentially incur a terrible traffic accident. In addition, considering VANET is usually implemented in civilian scenarios where locations of vehicles are closely related to drivers, VANET cannot be widely accepted by the public if VANET discloses the privacy information of the drivers, i.e., identity privacy and location privacy. Therefore, security and privacy preservation must be well addressed prior to its wide acceptance. Over the past years, much research has been done on considering VANET's unique characteristics and addressed some security and privacy issues in VANETs; however, little of it has taken the social characteristics of VANET into consideration. In VANETs, vehicles are usually driven in a city environment, and thus we can envision that the mobility of vehicles directly reflects drivers' social preferences and daily tasks, for example, the places where they usually go for shopping or work. Due to these human factors in VANETs, not only the safety related applications but also the non-safety related applications will have some social characteristics. In this thesis, we emphasize VANET's social characteristics and introduce the concept of vehicular social network (VSN), where both the safety and non-safety related applications in VANETs are influenced by human factors including human mobility, human self-interest status, and human preferences. In particular, we carry on research on vehicular delay tolerant networks and infotainment sharing --- two important non-safety related applications of VSN, and address the challenging security and privacy issues related to them. The main contributions are, i) taking the human mobility into consideration, we first propose a novel social based privacy-preserving packet forwarding protocol, called SPRING, for vehicular delay tolerant network, which is characterized by deploying roadside units (RSUs) at high social intersections to assist in packet forwarding. With the help of high-social RSUs, the probability of packet drop is dramatically reduced and as a result high reliability of packet forwarding in vehicular delay tolerant network can be achieved. In addition, the SPRING protocol also achieves conditional privacy preservation and resist most attacks facing vehicular delay tolerant network, such as packet analysis attack, packet tracing attack, and black (grey) hole attacks. Furthermore, based on the ``Sacrificing the Plum Tree for the Peach Tree" --- one of the Thirty-Six Strategies of Ancient China, we also propose a socialspot-based packet forwarding (SPF) protocol for protecting receiver-location privacy, and present an effective pseudonyms changing at social spots strategy, called PCS, to facilitate vehicles to achieve high-level location privacy in vehicular social network; ii) to protect the human factor --- interest preference privacy in vehicular social networks, we propose an efficient privacy-preserving protocol, called FLIP, for vehicles to find like-mined ones on the road, which allows two vehicles sharing the common interest to identify each other and establish a shared session key, and at the same time, protects their interest privacy (IP) from other vehicles who do not share the same interest on the road. To generalize the FLIP protocol, we also propose a lightweight privacy-preserving scalar product computation (PPSPC) protocol, which, compared with the previously reported PPSPC protocols, is more efficient in terms of computation and communication overheads; and iii) to deal with the human factor -- self-interest issue in vehicular delay tolerant network, we propose a practical incentive protocol, called Pi, to stimulate self-interest vehicles to cooperate in forwarding bundle packets. Through the adoption of the proper incentive policies, the proposed Pi protocol can not only improve the whole vehicle delay tolerant network's performance in terms of high delivery ratio and low average delay, but also achieve the fairness among vehicles. The research results of the thesis should be useful to the implementation of secure and privacy-preserving vehicular social networks.

Pulsed Electric Field (PEF) processing, a novel, non-thermal food preservation method, has been shown to inactivate both spoilage and pathogenic microorganisms, while minimizing changes in the physical and organoleptic qualities of the food, such as those observed under conventional thermal processing. An understanding of the inactivation mechanisms and kinetics of microorganisms exposed to lethal or sub-lethal PEF treatments would allow industry and consumers to better understand and evaluate the potential of PEF technology as an alternative or complement to traditional methods of food preservation. This study consisted of three sets of experiments which sought to determine: (i) the electrical conductivity (EC) of various liquid food products (apple, orange and pineapple juices, egg white, whole egg and egg yolk) at different temperatures (5--55°C); (ii) the capacity of PEF (15 kV cm-1, 0°C) to inactivate Escherichia coli O157:H7 in dialyzed liquid egg products; and (iii) the effect of PEF (20 or 30 kV cm-1) in combination with temperature (10--40°C) on the inactivation of E. coli and Salmonella Enteritidis in liquid egg yolk (EY), whole egg (WE), or egg white (EW). The treatment chamber design was based in part on regression equations of EC vs. temperature developed in the first set of experiments. After only 0.1 sec of PEF (15 kV cm-1) treatment, l, 3 and 3.5 log reductions of E. coli were noted in dialyzed egg white, egg yolk and whole egg, respectively. Kinetic models of bacterial inactivation were proposed. A 210 mus exposure to PEF (30 kV cm-1 ) resulted in log reductions of 5.0 and 5.0 in egg yolk, 3.9 and 3.6 in WE and, 2.8 and 3.6 in egg white, for E. coli and S. Enteritidis, respectively. A maximum energy of 914 J was required to inactivate S. Enteritidis in WE. In egg white, cells injured by PEF represented 0.9 and 0.4 log for S. Enteritidis and E. coli, respectively. An exponential decay model and an Arrhenius equation were

The validation and potential use of mathematical models to estimate the shelf-life of refrigerated food exposed to temperature abuse and basing such estimations on microbial growth was analyzed. Combined heat transfer, microbial growth models, and non-parametric statistical procedures formed a computer-based predictive tool to assess shelf-life and estimate the accuracy of the prediction. Experiments were carried out to assess the precision of the combined model parameters. The different situations analyzed considered stepwise fluctuations in environmental temperature and a change in package characteristic (size and packaging material). Computer simulations showed that even when the temperature abuse period constitutes a small fraction of the total exposure time (2%-3%), shelf-life can be highly affected (20%-30%). To analyze the precision of the combined model response, two sources of variation were considered, microbial growth and heat transfer parameters. First order, pseudo-zero order kinetics and Arrhenius model formed the basis for the microbial model. The accuracy of lag and exponential phase of microbial growth for a mixture of three microorganisms (P. fluorescens, S. aureus, and A. Iwoffi) was assessed using a nonparametric statistical procedure based on the bootstrap method. The activation energy (E [subscript a]) and the logarithm of the frequency factor (InK₀) were found to be 109±3.4 J/mole and 48.3±1.5 for the exponential phase of this microbial mixture. The values for the exponential phase were 152±4 J/mole and 64.0±1.7, respectively. These parameters together with experimental values for the overall heat transfer coefficient were used to analyze the precision of the model response. This precision was not affected by a change in environmental temperature and packaging characteristics and remained constant at ±1 day. Two different temperature abuse situations yield estimated shelf-life of 4.8±1 and 8.9±1 day, respectively. This result can not be generalized as it depends on the particular examples analyzed. / Graduation date: 1993

Graduation date: 1938

Graduation date: 1953

Graduation date: 1949

Graduation date: 1991