Miami University

About: Miami University is a education organization based out in Oxford, Ohio, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 9949 authors who have published 19598 publications receiving 568410 citations. The organization is also known as: Miami of Ohio & Miami-Ohio.

The impact of financial and nonfinancial incentives on business-unit outcomes over time.

Abstract: Unlike previous behavior management research, this study used a quasi-experimental, control group design to examine the impact of financial and nonfinancial incentives on business-unit (21 stores in a fast-food franchise corporation) outcomes (profit, customer service, and employee turnover) over time. The results showed that both types of incentives had a significant impact on all measured outcomes. The financial incentive initially had a greater effect on all 3 outcomes, but over time, the financial and nonfinancial incentives had an equally significant impact except in terms of employee turnover.

The invasive shrub, Lonicera maackii , reduces growth and fecundity of perennial forest herbs

Abstract: Effects of invasive plant species on native plant species are frequently assumed or inferred from compar- isons, but rarely quantified experimentally. Such quanti- fication is important to assessing risks and impacts of invasives. We quantified the effects of Lonicera maackii, an exotic shrub invasive in many eastern North American forests, on survival, growth, and reproduction of three perennial herbs: Allium burdickii, Thalictrum thalic- troides, and Viola pubescens. We predicted that the spring ephemeral, A. burdickii, would be most impacted, due to early leaf expansion of L. maackii. Field experiments were carried out in two deciduous forest stands, one (Gregg's Woodlot, GW) disturbed and the other (Western Woods, WW) relatively undisturbed. In each stand, individual herbs were transplanted into a blocked design of 60 plots where L. maackii was present, absent, or removed, and monitored for 5 growing seasons. Lonicera maackii did not affect survival of transplants, but reduced growth and final size of individuals of all three species. For two of the species, A. burdickii and V. pubescens, L. maackii reduced the proportion of live plants flowering in both stands, and reduced the seed or fruit number per flowering individual in GW. For T. thalictroides the proportion flowering was not affected, but seed number per flowering plant was reduced by L. maackii in both stands. For all three species, cumulative seed production over the course of the study was reduced by L. maackii. Overall, effects on the spring ephemeral, A. burdickii, were similar to effects on the other herbs. Because mortality of these established individuals was not affected, short-term studies might conclude forest herbs are unaffected by invasive shrubs. However, the growth and reproduction impacts documen- ted here suggest that populations are impacted in the long- term.

Trophic cascades and phytoplankton community structure

Abstract: Two predators of zooplankton, fish (yellow perch) and larval insects (Chaoborus), were manipulated within in situ mesocosms to assess their indirect effects on phytoplankton. The two predators caused similar reductions in zooplankton size and biomass, and as a consequence, zooplankton grazing rates on phytoplankton. However, phytoplankton increased relative to predator—free controls only in enclosures with fish and not in enclosures with Chaoborus, suggesting that fish have effects on phytoplankton independent of their effects on zooplankton grazing rates. Estimation of phosphorus excretion rates of zooplankton and fish suggests that fish render P more available to phytoplankton in two ways: (1) by directly excreting and egesting P, and (2) by increasing rates of P excretion by the zooplankton community. The latter effect resulted because small zooplankton have higher biomass—specific excretion rates than large zooplankton. The importance of nutrient regeneration is further supported by the response of phytoplankton community structure. Phytoplankton taxa exhibiting enhanced biomass in the presence of fish were those with high P requirements, including green and blue—green algae and dinoflagellates; other phytoplankton groups did not respond to manipulations. These results suggest that the mechanisms underlying the tropic cascade are complex and that predators affect phytoplankton by altering nutrient recycling rates as well as zooplankton grazing rates.

Extraction of tannin from fresh and preserved leaves.

Abstract: The extractability of tannin from fresh, lyophilized, and dried leaves collected at various times in the growing season was determined using the radial diffusion assay for protein-precipitating phenolics. The amount of tannin extracted depended on the method of leaf preservation and on the maturity of the leaf. Early in the season, more tannin was extracted from lyophilized leaves than from fresh leaves, but late in the season more tannin was extracted from fresh leaves. At all times, more tannin was extracted with aqueous acetone than with aqueous or acidic methanol.

The role of iron in bacterial infections, with special consideration of host-tubercle bacillus interaction.

Abstract: Various bacteria can invade dead or weakened tissues of an animal but only pathogenic parasites are able to establish themselves in viable host tissues and cause disease. To survive in a host and to invade its healthy tissues, a bacterial parasite has to possess mechanisms to neutralize or resist the natural defenses of the host and to use tissues and fluids of the infected body as sources of energy and materials essential for growth. Some pathogens secrete exotoxins which produce symptoms of disease, and, if not neutralized by antitoxins, may cause death. The active or passive acquisition of antibodies to exotoxins usually eliminates toxemia but not infection. Direct destruction of bacteria by specific antibodies and complement occurs only in a few bacterial species. Many pathogens do not produce exotoxins but nevertheless are able to invade tissues of the host, to multiply, and to spread. There is no single characteristic which could account for the pathogenicity of the non-toxigenic bacteria. Some of them survive in the host by being able to multiply rapidly in its tissue fluids and to resist engulfment by his phagocytic cells; once phagocytized, these bacteria are readily digested by intracellular enzymes. Other nontoxigenic parasites are unable to multiply in tissue fluids of the host but survive and multiply in its phagocytic cells. Because of this ability to persist in the intracellular environment, these nontoxigenic bacteria are called facultative intracellular parasites. The diseases caused by facultative intracellular parasites tend to be chronic and their nature is certainly not as acute as that of diseases caused by other bacteria.