THE INFLUENCE OF EWOM THROUGH INSTAGRAM SOCIAL MEDIA ON ONLINE PURCHASE INTENTION OF PRODUCTS: STUDY IN THE CITY OF BATAM

In general, this study aims to determine the effect of eWOM through social media Instagram on the purchase intention of products online in Batam City. This study uses a quantitative approach. The sample in this study amounted to 113 respondents who were users of social media Instagram. This research instrument using a questionnaire and analyzed using techniques Structural Equation Modeling (SEM) with the help of the SmartPLS 2.0 program. The results of this study indicate that trust, informational influence, moral obligation have significant involvement in eWOM, but the altruism variable does not have a significant effect on eWOM through social media Instagram and eWOM through social media Instagram has a strong influence on purchase intention of products online in Batam City. Based on the results of this study, it can be concluded that the exchange of information through eWOM can lead to consumer buying interest

Contactless Remote Induction of Shear Waves in Soft Tissues Using a Transcranial Magnetic Stimulation Device

This study presents the first observation of shear wave induced remotely within soft tissues. It was performed through the combination of a transcranial magnetic stimulation device and a permanent magnet. A physical model based on Maxwell and Navier equations was developed. Experiments were performed on a cryogel phantom and a chicken breast sample. Using an ultrafast ultrasound scanner, shear waves of respective amplitude of 5 and 0.5 micrometers were observed. Experimental and numerical results were in good agreement. This study constitutes the framework of an alternative shear wave elastography method

Breeding success, prey use, and mark-resight estimation of burrowing owls nesting on black-tailed prairie dog towns: plague affects a non-susceptible raptor

Department Head: N. LeRoy Poff.2010 Spring.Includes bibliographical references (pages 183-192).Introduced pathogens such as the bacterium (Yersinia pestis) that causes plague can have far-reaching effects on native ecosystems that go beyond the mortality of infected individuals. We investigated the effects of plague, prairie dog town dynamics, and rainfall on burrowing owls (Athene cunicularia) nesting in black-tailed prairie dog (Cynomys ludovicianus) burrows in the shortgrass steppe of northern Colorado. We examined effects on prey use, nest density, and breeding success, and used mark-resight methods for owl population estimation. Prairie dogs experience high mortality from plague, and their colonies are periodically extirpated by outbreaks. Plague does not make owls sick, but they may be affected as unmaintained burrows collapse, vegetation grows taller, and the anti-predator benefits of prairie dog association are lost. From 2005 - 2008, we monitored 322 nest attempts by 311 burrowing owl pairs on the Pawnee National Grassland and collected regurgitated pellets and prey remains. We banded owlets in 2007, and our first objective was to use a mark-resight protocol to estimate abundance, apparent survival, and temporary emigration. The Poisson-log normal mark-resight model (McClintock and White 2009) has recently been implemented in Program MARK (White and Burnham 1999). This model improves upon previous mark-resight models because individual identifications are not required 100% of the time, and individuals may die or be temporarily unobservable. Modeling showed that owlets in better condition that weighed more at first capture had higher survival throughout the summer and were more likely to be above ground. Our suggested improvements to field protocols should improve abundance estimation in the future. Our second objective was to examine the effects of precipitation, nest density, and plague on prey use and to determine whether prey composition influenced nest or fledging success. We quantified prey use and then analyzed diet composition using multi-response permutation procedures (MRPP) and indicator species analysis. Burrowing owls ate a huge variety of prey dominated by beetles, grasshoppers, ants, rodents, and songbirds. Insects comprised 95% of their diet by number, but only 11% by biomass. Owls in the driest year of our study and those at successful and very productive nests ate fewer birds and more mammals. Owl diet was unchanged by plague outbreaks, except that several bird species were less commonly eaten following epizootics. It appears that burrowing owls often forage outside of prairie dog towns, making town-level differences less relevant to owl diets. Our third objective was to determine the effects of plague, prairie dog town dynamics, and rainfall on nest fate, fledging success, and distances from each nest to its three nearest neighbors. Generalized linear modeling showed that rainfall was the strongest predictor of nest and fledging success, with higher rainfall associated with lower breeding success. Nests were more likely to succeed when plague events were more recent, and they produced more fledglings on towns where any extirpation was brief, and prairie dogs were otherwise resident on site for a longer time. Nests were closest together on recently plagued towns where prairie dog activity had been nearly continuous for a long time and recolonization was rapid. Although ubiquitous on active prairie dog towns, burrowing owls were nearly absent from towns that were not recolonized after plague epizootics. Both precipitation and plague influenced population dynamics of breeding burrowing owls. We found strong relationships among rainfall, prey species composition, and owl breeding success, and only half the owlets that emerged from burrows survived to fledge during the wettest July of our study. Precipitation regimes are expected to become more extreme in the future, which will likely have consequences for burrowing owls and other dryland species and may affect the size and frequency of plague outbreaks (Stapp et al. 2004). Although owls were absent from towns that were not recolonized after plague epizootics, it appears that burrowing owls can adapt to plague and even benefit in some cases. If conservation of burrowing owls is a primary goal, our results suggest that it will be more useful to preserve prairie dog habitat and connectivity between towns at a landscape scale than to intensively manage plague

A comparison of fish communities over different reef configurations in the northwestern Gulf of Mexico

High fishing pressure and limited natural habitat characterize the otherwise barren northwestern Gulf of Mexico. South Texas lacks extensive research of local natural and artificial reefs, and few studies report fish community and sportfish analysis of different reef densities. To alleviate this lack of data, fish abundances were monitored at different reef configurations in the PS-1047 Reef, 13 km off Port Mansfield, Texas, where 4000 concrete culverts were placed in 2011. Four culvert categories (CC1: 1-30 culverts, CC2: 31-70 culverts, CC3: 71-120 culverts, and CC4: 121-190 culverts in a 30-m radius), natural reefs and bare areas were sampled. Species abundances were assessed with 15- min SCUBA surveys, and total lengths of commercially valuable Lutjanus campechanus were measured. In summer 2013, water temperatures were warmer (25.1 ± 0.4°C), and surveys had significantly more adults and more even juvenile populations than in the summer of 2014 (22.8 ± 0.2°C). No fishes were observed at bare areas, whereas sites with structure had 186 ± 28 individuals from 13 ± 1 species. Fish communities did not significantly differ between reefs, yet significantly more adult individuals were seen on natural reefs than CC1, CC2, and CC4. CC3 resembled natural reefs with similarly high species richness and total abundance values. Lutjanus campechanus were found at all sites with structure, with an average 41 ± 6 individuals per site, and abundances did not significantly differ among reef categories. CC1 exhibited the largest Lutjanus campechanus, 362.9 ± 8.7 mm, whereas all other reef categories exhibited average lengths ranging from 296.5 to 322.8 mm. Longer individuals at CC1 may result from aggressive behaviors exhibited at sites with less suitable habitat. Using a previous study that assessed total length to age ratios in South Texas, the predicted age of Lutjanus campechanus was two years old. Findings suggest that culvert reefs are substantial improvements to otherwise bare areas, and reefs with about 100 culverts closely mimic species diversity of nearby natural reefs. Thus, it is recommended that future culvert reefs be deployed with 100 culverts in 100 m increments to cover four times more area than at PS-1047

Social plasticity and limited resilience of coral-dwelling gobies (genus Gobiodon) to climate change: outlook for coral-fish mutualisms in a changing world

Climate change is rapidly altering ecosystems on a global scale, and coral reefs are particularly vulnerable to climate-induced disturbances. Coral reefs depend on mutualisms with their foundation species, i.e. corals, and yet most of the literature has focused on their mutualisms with only one type of symbiont (algae). Little is known about how coral-fish mutualisms respond to climatic disturbances, and yet cyclones and heatwaves are increasingly devastating coral reefs. We urgently need to assess how coral-fish mutualisms respond to disturbances as changes in mutualisms have the potential for causing ecosystem-level changes. Yet fish in coral-fish mutualisms have often been overlooked in studies regarding environmental disturbances. There are multiple aspects of the life history, behaviour, and movement of fish that may impact their mutualisms with corals. Here, I investigated (1) whether both symbionts in coral-fish mutualisms respond similarly to climatic disturbances, and (2) what mechanisms from the fish perspective are likely responsible for how coral-fish mutualisms respond to climatic disturbances. I used a model coral-fish mutualism between coral hosts from the genus Acropora and coral-dwelling gobies from the genus Gobiodon in which both organisms provide important benefits for the resilience of each partner. I implemented a comparative approach by investigating multiple goby and coral species encountered in study locations to provide genus-wide understandings of how their coral-goby mutualisms are impacted by climatic disturbances. Particularly important is that gobies can live in social groups and living in groups can improve coral maintenance. Accordingly, first I provided a comprehensive review on how climate change is impacting the sociality of coral reef fish as the sociality of these taxa have only recently been investigated. Studies have shown that climate change affected the habitat and physiology of fishes, and each of these effects impacted their sociality. The review highlighted key changes to the sociality of these fish depending on how corals respond to disturbances, like reduction in coral size, shifts in coral communities, and health of corals. Secondly, I set the scene by monitoring coral-goby mutualisms throughout four extreme disturbances in the northern Great Barrier Reef (GBR): two cyclones and two heatwaves that caused mass bleaching events. In the aftermath and after a few years of recovery, there were more coral species, but corals were almost three times smaller. For gobies though, there were two times fewer coral species, there were fewer gobies, and most corals became absent of gobies when previously most were occupied. Alarmingly, this study highlighted that gobies declined far more than corals and were far slower to recover than their hosts. Finally, I used a combination of observational and manipulative studies to investigate the potential for coral gobies to exhibit plasticity in their host use, sociality, and movement in relation to disturbances. Following the same four extreme disturbances, I found that gobies shifted hosts to the newly abundant coral species. Although exhibiting host plasticity may be an advantage in the short-term, using alternative coral hosts may reduce the fitness of gobies, i.e. their growth rates. I then investigated whether gobies shifted their social tendencies to live in groups or in pairs following these four extreme disturbances in the northern GBR and following a single extreme disturbance in the southern GBR. Gobies no longer lived in groups, rarely in pairs, and primarily lived as solitary individuals after the four disturbances, whereas there was relatively little change in their social tendencies after the single disturbance. This study suggests that if consecutive disturbances become the norm, gobies may continue to decline if they primarily stay solitary as they need to live in pairs to breed. I then completed another study to investigate how predation risk, coral size and health, and number of group members affected the movement of gobies. I translocated gobies in situ into corals with varying sizes, number of individuals, and health. I replicated the study in a relatively undisturbed environment in Papua New Guinea, and in the highly disturbed environment following the four extreme disturbances in northern GBR. Regardless of the disturbance state, gobies preferred to face high costs of predation and did alter their movement based on coral size, health, or number of group members, even when predation risk was higher in disturbed environments. This suggests that gobies do not alter their movement plasticity based on environmental disturbances even though predation risk is heightened. This means that gobies exhibited host and social plasticity, but they did not exhibit movement plasticity to disturbances. I found that each mechanism of plasticity was likely responsible for a reduced recovery potential of gobies compared to their coral hosts. By combining the findings from each chapter of the thesis, I suggest that coral-fish mutualisms are highly vulnerable to climate change as fish experience barriers to recovery via host, social, and movement plasticity. Future conservation strategies should address declines in fish in order to maintain coral-fish mutualisms important for coral health