Establishment of a Prairie on a Borrow-Pit Site at the Bergamo-Mt. St. John Nature Preserve in Greene County, Ohio

Author Institution: Department of Biological Sciences, University of Cincinnati and Department of Biology, University of DaytonDuring the spring of 1986, development of a prairie was begun on a site at the Bergamo-Mt. St. John Nature Preserve located in Greene County, Ohio. A major objective of the project was to reclaim a sand and gravel borrow-pit. Prairie was chosen for reclamation of this area because prairie vegetation was present in the immediate area and that type of community is well-suited to the extremes in moisture conditions on the site. The prairie is intended to provide a habitat for some species being displaced by human disturbance and to provide a specific plant community within the preserve. To establish grasses, seeds obtained from Western sources were planted in April of 1986 by hydroseeding on the graded site. Just prior to this, seeds of several forbs obtained from Western sources were broadcast over the area. Subsequently, seeds of grasses and forbs collected locally were broadcast. For species more difficult to establish, plants were propagated in soil-filled plastic-film cylinders. These, and other plants collected locally from disturbed sites, were transplanted into holes prepared with a soil auger. After three seasons of growth, approximately 36 species of Ohio prairie indicator plant species, along with a number of species of animals, have become established on the site despite the severe drought of 1988

A Group-Based Yule Model for Bipartite Author-Paper Networks

This paper presents a novel model for author-paper networks, which is based on the assumption that authors are organized into groups and that, for each research topic, the number of papers published by a group is based on a success-breeds-success model. Collaboration between groups is modeled as random invitations from a group to an outside member. To analyze the model, a number of different metrics that can be obtained in author-paper networks were extracted. A simulation example shows that this model can effectively mimic the behavior of a real-world author-paper network, extracted from a collection of 900 journal papers in the field of complex networks.Comment: 13 pages (preprint format), 7 figure

Diversification Benefits from Foreign Real Estate Investment

Previous research has questioned the stability of international equity diversification. This study examines whether foreign real estate exists in a more segmented market and whether foreign real estate provides any diversification benefit beyond that obtainable from foreign stocks. Using data encompassing the stock market crash of 1987, foreign real estate was found to have a lower correlation with U.S. stocks than foreign stocks. This lower correlation is shown to be stable through time as foreign real estate has a lower correlation in nearly the entire time period. Foreign real estate was also found to have a significant weight in efficient international portfolios

Central European foreign exchange markets: a cross-spectral analysis of the 2007 financial crisis

This paper investigates co-movements between currency markets of Czech Republic, Poland, Hungary, Slovakia and the Euro in the year following the drying up of money markets in August 2007. The paper shows that assessing the degree of foreign currency co-movement by correlation can lead to concluding, erroneously, that financial contagion has not occurred. Using cross-spectral methods, the paper shows that defining contagion as changes in the structure of co-movements of asset prices encompasses more of the complex nature of exchange rate dynamics. What is shown is that, following August 2007, there is increased in the intensity of co-movements, but non-linearly. Focusing on the activities of a mix of banks and currency managers, it is suggested that changes in the structure of currency interaction present an unfavourable view of the contagion experienced by at least three of these currencies

Seasonal Responses of Filtration Rates to Temperature, Oxygen Availability, and Particle Concentration of the Freshwater Clam, Musculium partumeium (Say)

Seasonal filtration rates of a pond population of the freshwater pisidiid clam, Musculium par­tumeium (Say), were assessed by measuring the clearance of 2.02 µ.m latex beads from suspension and expressed in terms of FR = a(AFDW}b where FR = filtration rate (ml H20 · hr- 1 ) , AFDW = mg ash-free dry weight of a whole clam and a and b are constants. The a-values ( = FR of a 1-mg AFDW clam} vary seasonally with the highest rates corresponding to periods of maximum growth and reproduction in the spring and fall. Changes in b reflect the influence of body size on the weight-­specific rates (FR/AFDW). Seasonally a and b are inversely related. Therefore. seasonal increases in FR are proportionately greater for smaller clams. The 0,0 of FR is between 2-3 during the winter and decreases to 1.0 during the summer (temperature insensitivity) when clams are relatively inactive. At 20°c under aerobic conditions FR decreases as the concentration of suspension increases over a range of= 1.38-40 mg. · 1-1 with the FR for 1-mg AFDW clams going from 4.8 to 0.5; this minimum FR is maintained at higher concentrations. The amount of filtrate cleared (µ.g · clam- 1 • hr-1) initially increases as concentration increases (to = 13 mg -1 • I) then decreases before increasing again at concentrations\u3e =30 mg · I - 1• Ingestion must be less at higher concentrations since pseudofeces are produced at concentrations \u3e 22 mg · 1-1• Under anaerobic conditions FR is uniformly low at all concentrations. Seasonal responses of FR are assessed in terms of temperature. oxygen availability and particle concentration, and interpreted in terms of the interaction of growth, reproduction and population dyna­mics. These data have been integrated for 1-m2 of pond substrate. It is suggested that M. partumeium probably supplements filter-feeding with other mechanisms of energy intake such as deposit-feeding

Geometric and dynamic perspectives on phase-coherent and noncoherent chaos

Statistically distinguishing between phase-coherent and noncoherent chaotic dynamics from time series is a contemporary problem in nonlinear sciences. In this work, we propose different measures based on recurrence properties of recorded trajectories, which characterize the underlying systems from both geometric and dynamic viewpoints. The potentials of the individual measures for discriminating phase-coherent and noncoherent chaotic oscillations are discussed. A detailed numerical analysis is performed for the chaotic R\"ossler system, which displays both types of chaos as one control parameter is varied, and the Mackey-Glass system as an example of a time-delay system with noncoherent chaos. Our results demonstrate that especially geometric measures from recurrence network analysis are well suited for tracing transitions between spiral- and screw-type chaos, a common route from phase-coherent to noncoherent chaos also found in other nonlinear oscillators. A detailed explanation of the observed behavior in terms of attractor geometry is given.Comment: 12 pages, 13 figure