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Institution

University of Rhode Island

EducationKingston, Rhode Island, United States
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.


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Journal ArticleDOI
18 Jun 2008-PLOS ONE
TL;DR: A simple Lotka-Volterra predator-prey model is built on to provide a heuristic tool for distinguishing between the demographic effects of consumption and of anti-predator defenses, and for distinguishing among the multiple mechanisms by which anti-Predator defenses might reduce prey population growth rates.
Abstract: Background: Most ecological models assume that predator and prey populations interact solely through consumption: predators reduce prey densities by killing and consuming individual prey. However, predators can also reduce prey densities by forcing prey to adopt costly defensive strategies. Methodology/Principal Findings: We build on a simple Lotka-Volterra predator-prey model to provide a heuristic tool for distinguishing between the demographic effects of consumption (consumptive effects) and of anti-predator defenses (nonconsumptive effects), and for distinguishing among the multiple mechanisms by which anti-predator defenses might reduce prey population growth rates. We illustrate these alternative pathways for nonconsumptive effects with selected empirical examples, and use a meta-analysis of published literature to estimate the mean effect size of each pathway. Overall, predation risk tends to have a much larger impact on prey foraging behavior than measures of growth, survivorship, or fecundity. Conclusions/Significance: While our model provides a concise framework for understanding the many potential NCE pathways and their relationships to each other, our results confirm empirical research showing that prey are able to partially compensate for changes in energy income, mitigating the fitness effects of defensive changes in time budgets. Distinguishing the many facets of nonconsumptive effects raises some novel questions, and will help guide both empirical and theoretical studies of how predation risk affects prey dynamics.

262 citations

Journal ArticleDOI
TL;DR: In the second phase of the International Chemical Transport Experiment-B (INTEX-B) campaign as discussed by the authors, a new airborne OH reactivity instrument was designed and deployed for the first time on the NASA DC-8 aircraft, which was focused on the Asian pollution outflow over Pacific Ocean and was based in Hawaii and Alaska.
Abstract: . The measurement of OH reactivity, the inverse of the OH lifetime, provides a powerful tool to investigate atmospheric photochemistry. A new airborne OH reactivity instrument was designed and deployed for the first time on the NASA DC-8 aircraft during the second phase of Intercontinental Chemical Transport Experiment-B (INTEX-B) campaign, which was focused on the Asian pollution outflow over Pacific Ocean and was based in Hawaii and Alaska. The OH reactivity was measured by adding OH, generated by photolyzing water vapor with 185 nm UV light in a moveable wand, to the flow of ambient air in a flow tube and measuring the OH signal with laser induced fluorescence. As the wand was pulled back away from the OH detector, the OH signal decay was recorded; the slope of −Δln(signal)/Δ time was the OH reactivity. The overall absolute uncertainty at the 2σ confidence levels is about 1 s−1 at low altitudes (for decay about 6 s−1), and 0.7 s−1 at high altitudes (for decay about 2 s−1). From the median vertical profile obtained in the second phase of INTEX-B, the measured OH reactivity (4.0±1.0 s−1) is higher than the OH reactivity calculated from assuming that OH was in steady state (3.3±0.8 s−1), and even higher than the OH reactivity that was calculated from the total measurements of all OH reactants (1.6±0.4 s−1). Model calculations show that the missing OH reactivity is consistent with the over-predicted OH and under-predicted HCHO in the boundary layer and lower troposphere. The over-predicted OH and under-predicted HCHO suggest that the missing OH sinks are most likely related to some highly reactive VOCs that have HCHO as an oxidation product.

262 citations

Journal ArticleDOI
TL;DR: The phreatomagmatic analogue of plinian tephra is the phreatoplinian pyroclastic deposits as mentioned in this paper, formed by the interaction of water and silicic magma during explosive eruptions.
Abstract: We have recognized a type of pyroclastic deposit formed by the interaction of water and silicic magma during explosive eruptions. These deposits have a widespread dispersal, similar to plinian tephra, but the overall grain size is much tiner. Several deposits studied can be associated with caldera lakes or sea water and water/magma interaction is proposed to account for the fine grain size. Several examples have been studied, including the Oruanui Formation, N.Z., and the Askja 1875 deposit. Both show little downwind decrease in median diameter, a downwind decrease in sorting (σφ) (more evident in the Askja deposit) and coarse tail grading. The Askja example has base surge deposits near source and some Oruanui members show multiple thin beds near source; both are common features of phreatomagmatic deposits. Isopachs of the Askja deposit indicate a source under Lake Oskjuvatn in Askja Caldera and those of the Oruanui indicate a source under the NW part of Lake Taupo. In terms of dispersal area, volume and calculated eruption column heights, these deposits are similar to plinian. However, their extreme fragmentation due to magma/water interaction, superimposed on fragmentation imparted by carlier vesiculation, gives a much finer and more complex grain size distribution than plinian counterparts. The field of phreatomagmatic equivalents to plinian pumice deposits was unoccupied onWalker’s (1973) classification of explosive volcanic eruptions. Such deposits are the phreatomagmatic analogue of plinian deposits and the name « phreatoplinian » is proposed.

261 citations

Journal ArticleDOI
TL;DR: Evidence is presented that challenges the importance of pelvic morphology and mechanics in the evolution of human gestation and altriciality and suggests that limits to maternal metabolism are the primary constraints on human gestation length and fetal growth.
Abstract: The classic anthropological hypothesis known as the “obstetrical dilemma” is a well-known explanation for human altriciality, a condition that has significant implications for human social and behavioral evolution. The hypothesis holds that antagonistic selection for a large neonatal brain and a narrow, bipedal-adapted birth canal poses a problem for childbirth; the hominin “solution” is to truncate gestation, resulting in an altricial neonate. This explanation for human altriciality based on pelvic constraints persists despite data linking human life history to that of other species. Here, we present evidence that challenges the importance of pelvic morphology and mechanics in the evolution of human gestation and altriciality. Instead, our analyses suggest that limits to maternal metabolism are the primary constraints on human gestation length and fetal growth. Although pelvic remodeling and encephalization during hominin evolution contributed to the present parturitional difficulty, there is little evidence that pelvic constraints have altered the timing of birth.

260 citations


Authors

Showing all 11569 results

NameH-indexPapersCitations
James M. Tiedje150688102287
Roberto Kolter12031552942
Robert S. Stern12076162834
Michael S. Feld11955251968
William C. Sessa11738352208
Kenneth H. Mayer115135164698
Staffan Kjelleberg11442544414
Kevin C. Jones11474450207
David R. Nelson11061566627
Peter K. Smith10785549174
Peter M. Groffman10645740165
Ming Li103166962672
Victor Nizet10256444193
Anil Kumar99212464825
James O. Prochaska9732073265
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
202344
2022161
20211,105
20201,058
2019996
2018888