Virginia Commonwealth University

About: Virginia Commonwealth University is a education organization based out in Richmond, Virginia, United States. It is known for research contribution in the topics: Population & Health care. The organization has 23822 authors who have published 49587 publications receiving 1787046 citations. The organization is also known as: VCU.

Predator-prey naïveté, antipredator behavior, and the ecology of predator invasions

Abstract: We present a framework for explaining variation in predator invasion success and predator impacts on native prey that integrates information about predator–prey naivete, predator and prey behavioral responses to each other, consumptive and non-consumptive eff ects of predators on prey, and interacting eff ects of multiple species interactions. We begin with the ‘naive prey’ hypothesis that posits that naive, native prey that lack evolutionary history with non-native predators suff er heavy predation because they exhibit ineff ective antipredator responses to novel predators. Not all naive prey, however, show ineff ective antipredator responses to novel predators. To explain variation in prey response to novel predators, we focus on the interaction between prey use of general versus specifi c cues and responses, and the functional similarity of non-native and native predators. Eff ective antipredator responses reduce predation rates (reduce consumptive eff ects of predators, CEs), but often also carry costs that result in non-consumptive eff ects (NCEs) of predators. We contrast expected CEs versus NCEs for non-native versus native predators, and discuss how diff erences in the relative magnitudes of CEs and NCEs might infl uence invasion dynamics. Going beyond the eff ects of naive prey, we discuss how the ‘naive prey’, ‘enemy release’ and ‘evolution of increased competitive ability’ (EICA) hypotheses are inter-related, and how the importance of all three might be mediated by prey and predator naivete. Th ese ideas hinge on the notion that non-native predators enjoy a ‘novelty advantage’ associated with the naivete of native prey and top predators. However, non-native predators could instead suff er from a novelty disadvantage because they are also naive to their new prey and potential predators. We hypothesize that patterns of community similarity and evolution might explain the variation in novelty advantage that can underlie variation in invasion outcomes. Finally, we discuss management implications of our framework, including suggestions for managing invasive predators, predator reintroductions and biological control.

The rotarod test: an evaluation of its effectiveness in assessing motor deficits following traumatic brain injury.

Abstract: The purpose of the present experiment was to examine the effectiveness of a modified rotarod test in detecting motor deficits following mild and moderate central fluid percussion brain injury. In addition, this investigation compared the performance of the rotarod task with two other commonly used measures of motor function after brain injury (beam-balance and beam-walking latencies). Rats were either injured with a mild (n = 14) or moderate (n = 8) level of fluid percussion injury or were surgically prepared but not injured (n = 8). All rats were assessed on all tasks for 5 days following their respective treatments. Results revealed that both the mild and moderate injury levels produced significant deficits in the ability of the animals to perform the rotarod task. Performance on the beam-balance and beam-walking tasks were not significantly impaired at the mild injury level. It was only at the moderate injury level that the beam-balance and beam-walking tasks detected deficits in motor perform...

Current Trends in the Epidemiology of Nosocomial Bloodstream Infections in Patients with Hematological Malignancies and Solid Neoplasms in Hospitals in the United States

Abstract: A total of 2340 patients with underlying malignancy were identified among 22,631 episodes of nosocomial bloodstream infections (BSIs) in a prospectively collected database for 49 hospitals in the United States (Surveillance and Control of Pathogens of Epidemiologic Importance [SCOPE] Project). Data were obtained for the period of March 1995 through February 2001. Gram-positive organisms accounted for 62% of all BSIs in 1995 and for 76% in 2000 (P<.001), and gram-negative organisms accounted for 22% and 14% of all BSIs for these years, respectively. Neutropenia was observed in 30% of patients, so neutropenic and nonneutropenic patients were compared. In both, the predominant pathogens were coagulase-negative staphylococci (32% of isolates recovered from neutropenic patients and 30% of isolates recovered from nonneutropenic patients). The source of BSI was not determined for 57% of patients. The crude mortality rate was 36% for neutropenic patients and 31% for nonneutropenic patients.

Cluster-Assembled Materials

Abstract: Cluster-assembled materials offer the ability to tune component properties, lattice parameters, and thus coupling of physical properties through the careful selection and assembly of building blocks. Multi-atom clusters have been found to exhibit physical properties beyond those available from the standard elements in the periodic table; classification of the properties of such clusters effectively enables expansion of the periodic table to a third dimension. Using clusters as superatomic building blocks for hierarchically assembled materials allows these properties to be incorporated into designer materials with tailored properties. Cluster-assembled materials are currently being explored and methods developed to control their design and function. Here, we discuss examples of building block syntheses, assembly strategies, and property control achieved to date.