39 research outputs found

    Assessment of Information Security Culture in Higher Education

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    Information security programs are instituted by organizations to provide guidance to their users who handle their data and systems. The main goal of these programs is to protect the organization\u27s information assets through the creation and cultivation of a positive information security culture within the organization. As the collection and use of data expands in all economic sectors, the threat of data breach due to human error increases. Employee\u27s behavior towards information security is influenced by the organizations information security programs and the overall information security culture. This study examines the human factors of an information security program and their effect on the information security culture. These human factors consist of stringency of organizational policies, behavior deterrence, employee attitudes towards information security, training and awareness, and management support of the information security programs. A survey questionnaire was given to employees in the Florida College System to measure the human aspects of the information security programs. Confirmatory factor analysis (CFA) and Structural Equation Modeling (SEM) were used to investigate the relationships between the variables in the study using IBM® SPSS® Amos 24 software. The study results show that management support and behavior deterrence have a significant positive relationship with information security. Additionally, the results show no significant association between information security culture and organization policies, employee commitment and employee awareness. This suggests a need for further refinement of the model and the survey tool design to properly assess human factors of information security programs and their effects on the organizational security culture

    Marine benthic predator-prey interactions and global change.

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    Anthropogenic stressors such as habitat loss, extreme weather events, and acidification can change predator-prey interactions. An understanding of the mechanisms by which these stressors impact predator-prey interactions may elucidate the fate of bivalves in the face of global change. My dissertation research informs management of marine resources in Chesapeake Bay, which has experienced substantial seagrass and oyster reef loss, increased storm activity, and combined estuarine and atmospheric CO2 acidification. In my dissertation, I used field survey data, field caging experiments, laboratory mesocosm experiments, time-series analysis, and density-dependent mathematical models to assess the role of habitat, major storm events, acidification, and predators on bivalve distribution in lower Chesapeake Bay, with a special focus on the commercially important, thin-shelled clam species Mya arenaria, which has declined significantly in the past few decades.;In field surveys, seagrass supported one additional bivalve functional group (based on bivalve morphology and feeding mode) than all other habitat types, and bivalve diversity was 2754% higher in seagrass than in shell hash, oyster shell, coarse sand, and detrital mud habitats. The odds of finding M arenaria were higher in seagrass than in all other habitats. Predators likely consumed seasonal pulses of juveniles each year. In field caging experiments, blue crabs Callinectes sapidus were likely responsible for most of the mortality of juvenile M arenaria, which was 76.6% higher for caged juveniles than for uncaged individuals over 5 d. In mesocosm feeding trials, M arenaria maintained a low-density refuge from predation by blue crabs, and had higher survival in oyster shell or shell habitats as compared to sand or seagrass habitats. Time series analysis suggested M arenaria was subjected to a storm-driven phase shift to low abundance in 1972, which has been maintained by blue crab predation. Density-dependent predator-prey models parameterized with data from laboratory and field experiments confirmed the presence of a coexistence steady state at low densities of M arenaria, providing the theoretical proof-of-concept that M arenaria can exist in a low-density stable state in the face of blue crab predation. Acidification altered behavior of both predator (C. sapidus) and prey (M arenaria), resulting in no net change in proportional mortality of clams between acidified and control feeding trials.;My dissertation examined multiple lines of evidence to address the importance of structured habitat, extreme weather events, and acidification in the mediation of predator-prey dynamics. For the crab-bivalve predator-prey interactions examined here, predation exacerbated the effects of some anthropogenic stressors (habitat loss, extreme weather events) and ameliorated the impacts of other stressors (acidification) on bivalve prey. An understanding of density-dependent predation is a necessary component of an adaptive management strategy that can cope with climate change

    Habitat complexity and benthic predator-prey interactions in Chesapeake Bay

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    In Chesapeake Bay, the soft-shell clam Mya arenaria (thin-shelled, deep-burrowing) exhibits population declines when predators are active, and it persists at low densities. In contrast, the hard clam Mercenaria mercenaria (thick-shelled, shallow-burrowing) has a stable population and age distribution. We examined the potential for habitat and predators to control densities and distributions of bivalves in a field caging experiment (Mya only) and laboratory mesocosm experiments (both species). In the field, clams exposed to predators experienced 76.3% greater mortality as compared to caged individuals, and blue crabs were likely responsible for most of the mortality of juvenile Mya. In mesocosm experiments, Mya had lower survival in sand and seagrass than in shell hash or oyster shell habitats. However, crabs often missed one or more prey items in seagrass, shell, and oyster shell habitats. Predator search times and encounter rates declined when prey were at low densities, likely due to the added cost of inefficient foraging; however, this effect was more pronounced for Mya than for Mercenaria. Mercenaria had higher survival than Mya in mesocosm experiments, likely because predators feeding on Mercenaria spent less time foraging than those feeding on Mya. Mya may retain a low-density refuge from predation even with the loss of structurally complex habitats, though a loss of habitat refuge may result in clam densities that are not sustainable. A better understanding of density-dependent predator-prey interactions is necessary to prevent loss of food-web integrity and to conserve marine resources

    Role of habitat and predators in maintaining functional diversity of estuarine bivalves

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    Habitat loss is occurring rapidly in coastal systems worldwide. In Chesapeake Bay, USA, most historical oyster reefs have been decimated, and seagrass loss is expected to worsen due to climate warming and nutrient pollution. This loss of habitat may result in declining diversity, but whether diversity loss will equate to loss in ecosystem function is unknown. A bivalve survey was conducted in a variety of habitat types (seagrass, oyster shell, shell hash, coarse sand, detrital mud) in 3 lower Chesapeake Bay sub-estuaries from spring 2012 through summer 2013 to examine the correlation between bivalve densities, habitat type, habitat volume (of material retained on 3 mm mesh), and predator density. Bivalves were analyzed as functional groups based on feeding mode, living position, and predator defense strategy. On average, seagrass supported one additional functional group, and diversity was increased 68-94%, in seagrass compared to the other habitats examined. Species richness and functional group richness were positively correlated with habitat volume. The greatest densities of deposit-feeding bivalves were in detrital mud habitats, the greatest densities of thin-shelled and surface-dwelling bivalves were in seagrass habitats, and the greatest densities of armored bivalves were in oyster shell habitats. Small, thin-shelled bivalves were negatively correlated with densities of predators, including blue crabs Callinectes sapidus and cownose rays Rhinoptera bonasus. Overall, bivalve diversity was as - sociated with habitat type, habitat volume, and predator densities. These results suggest that all habitats, and particularly seagrass, play a role in maximizing bivalve functional diversity in Chesapeake Bay

    Effects Of Estuarine Acidification On An Oyster-Associated Community In New South Wales, Australia

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    Many of the features that make estuaries among the most productive natural systems on earth also make them prone to acidification. Understanding the effects of estuarine acidification on different components of an ecological community is an important step in identifying indicators of ecosystem degradation. This study examined the impact of estuarine acidification, as a result of acid sulfate soil runoff, on wild Sydney rock oysters Saccostrea glomerata and their associated epifaunal communities in estuaries experiencing acid sulfate soil runoff in New South Wales, Australia. The responses of oysters and their invertebrate epifaunal communities to chronic acidification (greater than 6 mo; represented by oyster source site conditions) were assessed by examining the differences in oyster communities associated with moderate acidification (3.5 km from the source of acidification) or low acidification (8.2 km from the source). Oysters from moderate-or low-acidification sites were transplanted to a site with high exposure to acidification (less than 3 km from the source) or back to their original source sites (control) to mimic episodic acidification (2 wk). Epifaunal mussels Xenostrobus securis and limpets Patelloida mimula showed a negative association with oyster mortality, suggesting that these communities are closely tied to oyster survival. Oyster-associated epifaunal communities exposed to both chronic and episodic acidification were significantly different from communities with low exposure. Epifaunal communities exposed to episodic acidification were significantly less diverse than the control. Spionid and syllid worms were significantly less abundant and the mussel X. securis was significantly more abundant on oysters with moderate exposure or chronic exposure to acidification, as compared with communities from areas with low exposure to acidification. The mussel X. securis and the snail Bembicium auratum were significantly less abundant in oyster communities that were exposed to episodic acidification, as compared with the control. In systems where community composition depends on a single habitat-forming species, maintaining resistance may rely on the ability of that species to persist in the face of environmental stress

    Are predator−prey model predictions supported by empirical data? Evidence for a storm-driven shift toan alternative stable state in a crab−clam system

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    A dynamic systems approach can predict steady states in predator−prey interactions,but there are very few examples of predictions from predator−prey models conforming to empirical data. Here, we examined the evidence for the low-density steady state predicted by a Lotka-Volterra model of a crab−clam predator−prey system using data from long-term monitoring, and data from a previously published field survey and field predation experiment. Changepoint analysis of time series data indicate that a shift to low density occurred for the soft-shell clam Mya arenaria in 1972, the year of Tropical Storm Agnes. A possible mechanism for the shift is that Agnes altered predator−prey dynamics between M. arenaria and the blue crab Callinectes sapidus, shifting from a system controlled from the bottom up by prey resources, to a system controlled from the top down by predation pressure on bivalves, which is supported by a correlation analysis of time series data. Predator−prey ordinary differential equation models with these 2 species were analyzed for steady states, and low-density steady states were similar to previously published clam densities and mortality rates, consistent with the idea that C. sapidusis a major driver of M. arenaria population dynamics. Relatively simple models can predict shifts to alternative stable states,as shown by agreement between model predictions (this study) and published field data in this system. The preponderance of multispecies interactions exhibiting nonlinear dynamics indicatesthat this may be a general phenomenon

    Virginia Institute of Marine Science 2011 Greenhouse Gas Inventory Report

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    During the spring of 2011, members of the VIMS Green Team, with support from the College of William and Mary’s Committee on Sustainability, collected data on resource use at the VIMS Gloucester Point campus in order to monitor our greenhouse gas emissions and develop methods for reducing our carbon footprint in the future. We processed these data using the Campus Carbon Calculator, a tool developed by Clean Air Cool Planet, a nonprofit organization. This program, used by over 1,200 colleges and universities, calculates the total greenhouse gas emissions of a campus using emissions factors developed by the Intergovernmental Panel on Climate Change

    Traces of Fallback Breccia on the Rim of Barringer Meteorite Crater (a.k.a. Meteor Crater), Arizona

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    Barringer Meteorite Crater (a.k.a. Meteor Crater), Arizona, is one of the youngest and best preserved impact craters on Earth. For that rea-son, it provides a baseline for similar craters formed in the geologic past, formed elsewhere in the Solar Sys-tem, and illuminates the astronomical and geological processes that produce them. The crater has not, how-ever, escaped erosion completely. While Shoemaker [1] mapped a breccia with fallback components inside the crater, he did not locate it beyond the crater rim. He only found remnants of that type of debris in re-worked alluvium [1; see also 2]. Fallback breccia and any base-surge deposits have, thus, been missing components in studies of material ejected beyond the transient crater rim
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