Distributed interaction between computer virus and patch: A modeling study

The decentralized patch distribution mechanism holds significant promise as an alternative to its centralized counterpart. For the purpose of accurately evaluating the performance of the decentralized patch distribution mechanism and based on the exact SIPS model that accurately captures the average dynamics of the interaction between viruses and patches, a new virus-patch interacting model, which is known as the generic SIPS model, is proposed. This model subsumes the linear SIPS model. The dynamics of the generic SIPS model is studied comprehensively. In particular, a set of criteria for the final extinction or/and long-term survival of viruses or/and patches are presented. Some conditions for the linear SIPS model to accurately capture the average dynamics of the virus-patch interaction are empirically found. As a consequence, the linear SIPS model can be adopted as a standard model for assessing the performance of the distributed patch distribution mechanism, provided the proper conditions are satisfied

Toxicological Effects of Cerium Oxide Nanoparticle Aggregates on Caenorhabditis elegans

Assessing the toxicity and unique reactivity of nanoparticles in biological systems has become an relevant and quickly growing area of environmental toxicology research. The broad use of nanoparticles in industrial and commercial commodities results in exposure of these nano-compounds to the environment, the ecosystems, and humans. While previous data has suggested that cerium oxide (CeO2) nanoparticles are relatively safe to cultured cells much less is known about the potential toxicity of these materials at the organismal level. In this study we employed transgenic Caenorhabditis elegans (C. elegans) strains to assess the toxicity of CeO2 nanoparticles under “real-world” conditions. Our findings indicate that while exposure to aggregated CeO2 in C. elegans has no effect on average life span, it is associated with decreases in nematode body length, progeny count, and increased organismal stress. These findings demonstrate that exposure to aggregated CeO2 particles (0-17.21 ug/mL) may be associated with diminished organismal fitness in C. elegans

What leads to effective science-teaching practices in preschool classrooms? An examination of teachers’ person, context, and time influences on science teaching

Science is a natural conduit for children to learn about, and interact with, the natural world (McClure et al., 2017), yet early childhood classrooms are reported as having fewer science learning opportunities, and teachers have more missed teachable moments (Greenfield et al., 2009; Tu, 2006). In an effort to understand the influences of science instruction in early care and education classrooms, four preschool teachers were interviewed about their past and present science-related teaching and learning experiences. Classroom observations also were conducted to capture science-teaching practices and types of science disciplines covered in classroom activities. Using Bronfenbrenner’s bioecological theory (Bronfenbrenner & Morris, 2006) as a framework, the person characteristics and the systems of context and the influence of time regarding these teachers’ science experiences were considered within their ability to shape current classroom practices. The research questions focused on what past and present formal and informal science learning experiences influenced science-teaching practices and how those experiences affected the facilitation of science in these classrooms. Results indicated that prior science learning experiences and personal characteristics did influence science instruction. The systems of context plus past science learning experiences, as well as science-teaching beliefs, science self-efficacy, and science and math anxiety, were all critical to how these teachers implemented science activities in their classrooms. Links between specific aspects of the interviews and observations provided evidence to support the importance of past and present science-related learning experiences for teacher development in current science-teaching practices

INTERNET FRAUD AND ITS EFFECT ON NIGERIA’S IMAGE IN INTERNATIONAL RELATIONS

Internet fraud has become an increasing form of computer crime. This study investigated the effects of internet fraud on Nigeria’s image in international relations. The study adopted quantitative method and descriptive survey. Journals and materials from internet complemented the major sources. Findings showed that unemployment and poverty are major causal factors of internet fraud. The study concluded that, internet use by Nigerians has come with fraudulent acts, and this has put Nigeria under scrutiny and brought negative image in international relations. The study recommended that, government should enact a comprehensive law on internet fraud and empower graduates by providing employment

The effects of plastic related phthalates (DEHP) upon ragworm, Hediste diversicolor

The exposure of the general public to phthalates is widespread as well as quite variable. Many human consumer products consist of a range of phthalates as ingredients of plastic materials. These include building materials, clothing, household furniture, cosmetics, pharmaceuticals, medical equipment, dentures, nutritional supplements, food packaging materials, children toys, modeling clay, waxes, glow sticks, cleaning materials, lubricants, automobile parts and also some insecticides (Schettler, 2005).Animals are exposed in their natural habitats to a variety of human activities including those related to dissolved chemicals that are released into aquatic systems and may impact their fitness and survival. The responses of animals to stress, generated by these chemicals, determines their biochemical and behavioural fitness. Phthalate esters are example of such chemicals. Di-2-ethylhexyl phthalate (DEHP) and Hediste diversicolor were used for the purpose of this study. Hediste diversicolor were exposed to various low concentrations of 0.05, 2, and 10 μg/L of DEHP in long term exposures (3 months), and to high concentrations of 100, and 500 μg/L DEHP in short term exposure studies (7 days). The study aims to provide evidence that the accumulation of DEHP in H. diversicolor results in changes to their behaviours, specifically feeding and burrowing activity, as well as changes in their biochemical responses to phthalate driven oxidative stress via catalase and superoxide dismutase enzymes. DEHP showed different levels of persistence in seawater depending on concentrations. DEHP accumulated significantly more in H. diversicolor and persisted also in the sediment, while it degraded quickly in seawater. Exposure to DEHP generated behavioural impairments in H. diversicolor in the form of a decrease in the feeding time and an increase in the burrowing time, a typical predator escape behaviour. In addition to this stressed worm also showed an increase in two biomarkers of oxidative-stress, CAT enzymes and stability in SOD enzymes. Field samples showed fluctuations of DEHP over the year and significant differences in DEHP levels between various locations in the Humber Estuary, but generally DEHP levels are significantly higher in H. diversicolor followed by the sediment and seawater

Cost and behavioural avoidance of trematode cercariae in fathead minnows

xi, 84 leaves : ill. ; 29 cmNatural selection should favour host defenses that reduce a host’s exposure to parasites or reduce their negative effects. One strategy that resolves the substantial costs of host immunity and/or tolerance is to avoid infective stages altogether. For fish, behavioural avoidance is well-known for defense against aquatic predators, but it is poorly known for defense against parasites. I used a model system that is amenable to experimental manipulation to test the behavioural avoidance hypothesis for fathead minnows exposed to the larvae of two of their common flatworm parasites. First, I showed that minnows exposed to a liver encysting trematode, Ornithodiplostomum sp. showed an increase in lipid peroxidation, an indicator of oxidative stress, persisting through worm development. Three lines of evidence provided support for the behavioural avoidance hypothesis. First, shoal area decreased in groups of minnows exposed to O. ptychocheilus cercariae compared to those exposed to cues from other aquatic threats. Second, average worm numbers were 50 % lower in fish confined to artificial shoals compared to non-shoaling minnows, indicating that shoaling reduces risk of exposure. The third experiment showed that minnows within the centre of shoal reduced their risk of infection by 67%. Taken together, these results demonstrate a cost of trematode infection on minnows, that minnows can detect infective larvae within the water column, and that social living reduces a hosts’ risk of exposure

Momentum: Research & Innovation for Spring 2016

The Spring 2016 issue of Momentum: Research & Innovation, a periodical focused on research at the University of Rhode Island

Wrack Lines Spring-Summer 2022, Volume 22, Number 1

All Creatures Great and Mostly Small: from the sea to the sky to your garden is the them of the Spring-Summer 2022 issue. Articles include: Editor\u27s Column; A Scuba View of Long Island Sound; Bill Palmer: Diving into History; Rex Brasher: Connecticut\u27s greatest unknown artist left a legacy of bird masterpieces; Copepod Survival: experiment with tiny marine creatures reveals future cost of climate change; Beyond Butterflies and Bumblebees: many lesser known but common insects are beneficial for the healthy garden and planet; Ash Creek in Fairfield: \u27shellfish paradise\u27 that can guide future restoration; and Drone Technology: a tool that could help advance shellfish restoration efforts