1,904 research outputs found
Intimidation or Impatience? Jump Bidding in On-line Ascending Automobile Auctions
We run a large field experiment with an online company specializing in selling used automobiles via ascending auctions. We manipulate experimentally the maximum amount which bidders can bid above the current standing price, thus affecting the ease with which bidders can engage in jump bidding. We test between the intimidation vs. costly bidding hypotheses of jump bidding by looking at the effect of these jump-bidding restrictions on average seller revenue. We find evidence consistent with costly bidding in one market (Texas), but intimidation in the other market (New York). This difference in findings between the two markets appears partly attributable to the more prominent presence of sellers who are car dealers in the Texas market.
Prayer, leadership, and church planting movements : learning from the prayer-lives of Western renewal movements and their leaders
https://place.asburyseminary.edu/ecommonsatsdissertations/2560/thumbnail.jp
Microbial community dynamics in denitrifying biofilters receiving agricultural drainage
Subsurface drains (tile drains) used to augment drainage in agricultural fields serve as a major pathway for agricultural nitrate pollution to enter surface waters. Used primarily in the Midwestern United States, nitrates from tile drainage systems contribute to eutrophication within the Gulf of Mexico, ultimately leading to the formation of the Gulf of Mexico hypoxic zone. One cost-effective solution for reducing the quantity of nitrate entering surface waters is the denitrifying biofilter. A typical denitrifying biofilter consists of a woodchip-filled trench inline with the drainage tile; woodchips provide a carbon substrate to the microorganisms that convert nitrate to nitrogen gas through the denitrification pathway.
Research to date has focused on applying traditional engineering approaches to improve biofilter performance and reliability. Although previous work has produced valuable results related to the selection of appropriate biofilter media, and optimization of operational parameters, denitrifying biofilters still perform somewhat unpredictably. Therefore, in this work we sought to understand how environmental and management factors affect the microbial communities responsible for biofilter functional.
To do so, we employed two different approaches. First, in our spatial study we sampled one biofilter over the course of an afternoon in 2007 to determine how total and denitrifying bacterial communities varied by depth, transect, and position along a transect. Second, in our temporal study we sampled three biofilters over two years, January 2009 â December 2010, to determine how total bacterial, denitrifying bacterial, and fungal communities correlated with environmental and management variables over time. Total bacterial community structure was analyzed by Automated Ribosomal Intergenic Spacer Analysis (ARISA), denitrifying bacteria community structure was determined by Terminal Restriction Fragment Length Polymorphism (T-RFLP) of nosZ (one of the nitrous oxide reductase genes), and fungal ARISA (FARISA) was used to determine fungal community structure.
Spatial and temporal results from the biofilter studies have provided valuable insight into how microbial communities, essential to the functionality of the denitrifying biofilter, vary over space and time. Results from our spatial study indicate that the composition of the total bacterial community varied by depth and sampling transect, but not by sampling position along a transect. Denitrifying bacteria community composition, unlike total bacteria, showed little variance by depth, transect, or sampling position.
Results from our temporal study indicate that depth and season were two of the most important factors influencing the structure of total bacterial, fungal, and denitrifying bacterial communities within all three biofilters. Correspondence analysis results suggest that microbial community structuring by depth may have been driven by moisture and temperature gradients. In addition to depth, microbial community composition was influenced by seasonal factors within all three denitrifying biofilters. For 2009 and 2010 bi-annual seasonal variation was observed for samples collected in January â June or July â December. Results from correspondence analysis suggest that seasonality was likely driven by moisture, water flow, and temperature. In addition to observing patterns in community composition related to depth and season, we were able to identify small subsets of the total bacterial, denitrifying, and fungal populations that were either influential in shaping the overall community structure, were correlated to strong biofilter performance, or both.
The application of denitrifying biofilters in tile drain networks shows the promise of significantly reducing anthropogenic inputs of nitrogen into aquatic ecosystems. By developing an understanding of how microbial population dynamics, environmental parameters, and management factors relate to biofilter performance, reliability, stability and resilience, the effectiveness and viability of the denitrifying biofilter as a treatment technology will ultimately be enhanced
The Political Economy of the Transition from Logging to Mining in Solomon Islands
Solomon Islanders have more than four decades of
experience with large-scale commercial logging of
natural forests, which still accounts for around 70
per cent of exports, 15 per cent of GDP and 14 per
cent of domestically sourced government revenues
(World Bank 2015:139). However, having logged well
beyond the sustainable yield almost every year since
1981, and despite previous predictions of the exhaustion
of the resource having proved to be incorrect,
there are signs that logging is set to decline. For
example, in 2012 there were 102 active licensed logging
operations, down from 333 in 2008, and these
are now mostly restricted to three of the nine provinces
â Isabel, Makira Ulawa and Western.AusAI
Elizabeth Yates and Matthew Porter in a Joint Junior Voice Recital
This is the program for the joint junior voice recital of soprano Elizabeth Yates and baritone Matthew Porter. Pianist Bradley Permenter accompanied Yates; pianist Jonathan Besanson accompanied Porter. The recital took place on March 23, 1984, in the Mabee Fine Arts Center Recital Hall
SB04-09/10: The Forest Jobs and Recreation Act of 2009
SB04-09/10: The Forest Jobs and Recreation Act of 2009. This resolution passed unanimously during the September 30, 2009 meeting of the Associated Students of the University of Montana (ASUM)
EB Sagamore Parkway Over the Wabash River Bridge Project
The Sagamore Parkway bridges over the Wabash River are vital crossings for the citizens of West Lafayette and Lafayette. This presentation will walk attendees through the entire design and construction process for this unique bridge replacement project. The presentation will also discuss Parsonsâ role with the JTRP project that focuses on the verification of the substructure design loads by using embedded strain gauges that were installed in the substructure
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