University of Rhode Island

About: University of Rhode Island is a education organization based out in Kingston, Rhode Island, United States. It is known for research contribution in the topics: Population & Bay. The organization has 11464 authors who have published 22770 publications receiving 841066 citations. The organization is also known as: URI & Rhode Island College of Agriculture and the Mechanic Arts.

The intensity of plinian eruptions

Abstract: Peak intensities (magma discharge rate) of 45 Pleistocene and Holocene plinian eruptions have been inferred from lithic dispersal patterns by using a theoretical model of pyroclast fallout from eruption columns. Values range over three orders of magnitude from 1.6 × 106 to 1.1 × 109 kg/s. Magnitudes (total erupted mass) also vary over about three orders of magnitude from 2.0 × 1011 to 6.8 × 1014 kg and include several large ignimbrite-forming events with associated caldera formation. Intensity is found to be positively correlated with the magnitude when total erupted mass (tephra fall, surges and pyroclastic flows) is considered. Initial plinian fall phases with intensities in excess of 2.0 × 108 kg/s typically herald the onset of major pyroclastic flow generation and subsequent caldera collapse. During eruptions of large magnitude, the transition to pyroclastic flows is likely to be the result of high intensity, whereas the generation of pyroclastic flows in small magnitude eruptions may occur more often by reduction of magmatic volatile content or some transient change in magma properties. The correlation between plinian fall intensity and total magnitude suggests that the rate of magma discharge is related to the size of the chamber being tapped. A simple model is presented to account for the variation in intensity by progressive enlargement of conduits and vents and excess pressure at the chamber roof caused by buoyant forces acting on the chamber as it resides in the crust. Both processes are fundamentally linked to the absolute size of the pre-eruption reservoir. The data suggest that sustained eruption column heights (i.e. magma discharge rates) are indicators of eventual eruption magnitude, and perhaps eruptive style, and thus are key parameters to monitor in order to assess the temporal evolution of plinian eruptions.

The protozoan-metazoan trophic link in pelagic ecosystems

Abstract: The evidence for a qualitatively and quantitatively important trophic link between planktonic Protozoa and higher order metazoan consumers is reviewed. the available data are obtained primarily, but not exclusively, from laboratory studies of calanoid copepod consumers and tintinnid ciliate prey from marine estuarine and nearshore environments. the data indicates that the protozoan-metazoan link is of similar magnitude and importance in the pelagic ecosystems of freshwaters. It is proposed that planktonic Protozoa constitute a high quality, nitrogen-rich food in the diets of their metazoan consumers. Implications of die trophic link to the consumers, prey, and ecosystem are discussed.

Economic Distress and Intimate Violence: Testing Family Stress and Resources Theories

Abstract: Hypotheses shaped by family stress and resource theories about the impact of household economic indicators on the risk of violence against women in intimate relationships are tested with a data set built from the initial two waves of the National Survey of Families and Households (NSFH) and the 1990 U.S. Census. Measures of employment status, job conditions, and economic well-being for male and female partners are examined with logistic regression analyses as predictors of the odds of male-to-female intimate violence. Results underline the importance that partners attach to each other's work performance and their feelings of financial well-being in assessing whether job holding and household income serve to elevate or reduce the risk of intimate partner violence toward women.