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Management of Remnant Prairie Ecosystems: Soil Transfer, Fire, and Exotic Species Invasion
Get PDFProperty management is an important aspect in sustaining the Earth’s ecosystems. Anthropogenic changes to the planet have made conservation important in maintaining species abundance and diversity as well as limit damages to sensitive ecosystems. Invasive species have become a standard, consistent problem in managed ecosystems. Such species often invade into disturbed areas, which commonly are a result of restoration or other management activities. In dredging open water bodies at Eagle Marsh Nature Preserve (Allen County, IN), artificial mounds were constructed with the soil removed. This movement of soil created a disturbance which facilitated for the recruitment and colonization of invasive species. The purpose of this study was to quantify the effectiveness of transferring a native seed bank in a mesic prairie to the artificial mounds as a method of controlling invasive species. The native seed bank in the mesic prairie would be lost due to additional management. This study was conducted with greenhouse and field experimentation. Soil samples containing the seed bank were moved to a greenhouse to quantify plant emergence following different intact and mixed soil treatments. All emerging plant species were identified and counted. All treatment methods contained a high diversity of native species and a low diversity of invasive species with the exception of the seed bank soil mixed with soil from the mounds. The mound mixed soil contained a higher diversity of invasive species than other treatments. A plant survey of the mounds was conducted in July 2014. In October 2014, 960 m2 of soil was transferred from the donor site to the mounds. A post-move survey conducted in July 2015 indicated the native species diversity increased while the diversity of invasive species decreased. Soil transfer as a management strategy was appropriate in this situation where a large native seed bank in a donor region existed. By moving soil from one location to another, we were able to promote native plant establishment and reduce invasive species emergence. While soil transfer is effective, other management strategies may not have the same results. Callery pear (Pyrus calleryana) is an invasive tree introduced to North America as an ornamental from southwest Asia. It easily invades disturbed areas, causing a disruption to mid- to late-successional species establishment. The purpose of this study was to assess Callery pear demographics in a managed prairie and quantify the effects of a prescribed fire management strategy on Callery pear density and recruitment. This study was conducted at Arrowhead Prairie (Allen County, IN), managed by Little River Wetlands Project (LRWP). Before 2009, Arrowhead Prairie was primarily used for agriculture. Following LRWP acquisition, the property has undergone active management including native plant seeding and prescribed fire. The prairie was divided into a north and south section using a historic ditch, with the south section burned in April 2014 and the north section burned in May 2015. Bare seeds, fruit, first-year seedlings, and second-year seedlings were also burned in a separate controlled experiment. Fire in both years top killed Callery pear individuals, with 100% of surveyed trees producing epicormic shoots and 83% producing more than one epicormic sprout. First-year seedlings exposed to the fire had a 3% resprout rate while all seconds-year seedlings resprouted. In contrast, 13% of individuals at Arrowhead Prairie had epicormic shoots without fire. Trees were significantly shorter post-burn than prior to the burn; however, root collar diameter was not different, suggesting that resources were used in primary growth. While fire did reduce stem height, it did increase the number of stems occurring within the burned section due to epicormic sprouting. Root stored reserves provided necessary energy to produce numerous sprouts by the majority of pear trees, although no trees produced flowers during the duration of the study. Plant age likely plays an important role in response to fire, with seeds and fruits succumbing. However, older seedlings may survive with increased epicormic shoot production. Multiple techniques combined with relevant studies allows for land managers to make appropriate decisions in terms of management. Although many of these techniques are not universal, a wide range of researched techniques provides multiple avenues of approach when managing a parcel of land
Implementation of the Continuous Space Language Model on a Heterogeneous Mobile Processor
Get PDFMobile processors continue to increase in performance while becoming more power efficient, providing consumers with improved gaming, multi-media, and browsing, along with longer lasting device usage. To keep up with consumer multimedia demand, mobile processor manufacturers have begun to integrate Graphical Processing Units (GPU) on mobile processors, providing users with the high performance graphics required for mobile gaming applications. The addition of integrated GPUs to the mobile processors also offers new opportunities for introducing to the mobile platform computationally intensive algorithms that were formerly impractical when running on the mobile CPU processor alone. GPU manufacturers such as NVIDIA are scaling down their GPU architecture from desktop systems to those developed for use on mobile processors, such as the Tegra K1, featuring a single GPU processing core.
This research effort investigates the performance of the computationally intensive Continuous Space Language Model (CSLM) algorithm on the NVIDIA Tegra K1 mobile processor and compares its performance on this platform to that of the desktop GPU platform reported by Thompson et al. [1]. The performance on the embedded GPU platform will also be compared to that of a conventional embedded CPU. However, first, the execution time of the algorithm will be observed while executing on a laptop CPU platform to provide a reference point for the performance of the Tegra K1 CPU processor(s). Next, the algorithm will be configured to execute solely on the Tegra K1 CPU processor(s), and the execution time will be observed. Finally, the execution time of the algorithm will be observed after porting only the computationally intensive portions of the algorithm to the Tegra K1 GPU while other portions remain on the embedded CPU
Suspended Because of Social Media? Students’ Knowledge and Opinions of University Social Media Policies and Practices
Get PDFIn this exploratory study, we examined undergraduates’ (N ¼ 298) knowledge of their university’s social media policies, understanding of free speech and privacy protections, opinions about university monitoring and discipline for personal social media posts, and perceptions of fairness regarding recent cases of student discipline for personal social media use. The results of our study indicate that most undergraduates are highly underinformed as to whether or not their university has a social media policy, particularly if the students are early in their academic careers and do not engage in many online privacy protection behaviors. Most participants were also misinformed as to whether free speech and/or privacy protections will shield them from university discipline. In addition, most participants (78%) were opposed to the idea of universities monitoring students’ personal social media accounts, though significantly fewer (68%) were opposed to monitoring student athletes’ social media. Finally, when asked about several recent cases involving student discipline, most participants were generally opposed to a variety of university disciplinary actions regarding students’ social media posts. We discuss these findings as they relate to the need for better social media policy training for students, as well as the potential impact on students’ academic and future careers
The Response Regulator Npun_F1278 is Essential for Scytonemin Biosynthesis in the Cyanobacterium Nostoc Punctiforme ATCC 29133
No full textFollowing exposure to long-wavelength ultraviolet radiation (UVA), some cyanobacteria produce the indole-alkaloid sunscreen scytonemin. The genomic region associated with scytonemin biosynthesis in the cyanobacterium Nostoc punctiforme includes 18 co-transcribed genes. A two-component regulatory system (Npun_F1277/Npun_F1278) directly upstream from the biosynthetic genes was identified through comparative genomics and is likely involved in scytonemin regulation. In this study, the response regulator Npun_F1278 was evaluated for its ability to regulate scytonemin biosynthesis using a mutant strain of N. punctiforme deficient in this gene, hereafter strain D1278. Following UVA radiation, the typical stimulus to initiate scytonemin biosynthesis, D1278 was incapable of producing scytonemin. A phenotypic characterization of D1278 suggests that aside from the ability to produce scytonemin, the deletion of the Npun_F1278 gene does not affect the cellular morphology, cellular differentiation capability, or lipid-soluble pigment complement of D1278 compared to the wild type. The mutant, however, had a slower specific growth rate under white light and produced ~2.5-fold more phycocyanin per cell under UVA than the wild type. Since D1278 does not produce scytonemin, this study demonstrates that the response regulator gene Npun_F1278 is essential for scytonemin biosynthesis in N. punctiforme. While most of the evaluated effects of this gene appear to be specific for scytonemin, this regulator may also influence the overall health of the cell and phycobiliprotein synthesis, directly or indirectly. This is the first study to identify a regulatory gene involved in the biosynthesis of the sunscreen scytonemin and posits a link between cell growth, pigment synthesis, and sunscreen production
Forces from the Portal Govern the Late-Stage DNA Transport in a Viral DNA Packaging Nanomotor
No full textIn the Phi29 bacteriophage, the DNA packaging nanomotor packs its double-stranded DNA genome into the virus capsid. At the late stage of DNA packaging, the negatively charged genome is increasingly compacted at a higher density in the capsid with a higher internal pressure. During the process, two Donnan effects, osmotic pressure and Donnan equilibrium potentials, are significantly amplified, which, in turn, affect the channel activity of the portal protein, GP10, embedded in the semipermeable capsid shell. In the research, planar lipid bilayer experiments were used to study the channel activities of the viral protein. The Donnan effect on the conformational changes of the viral protein was discovered, indicating GP10 may not be a static channel at the late stage of DNA packaging. Due to the conformational changes, GP10 may generate electrostatic forces that govern the DNA transport. For the section of the genome DNA that remains outside of the connector channel, a strong repulsive force from the viral protein would be generated against the DNA entry; however, for the section of the genome DNA within the channel, the portal protein would become a Brownian motor, which adopts the flash Brownian ratchet mechanism to pump the DNA against the increasingly built-up internal pressure (up to 20 atm) in the capsid. Therefore, the DNA transport in the nanoscale viral channel at the late stage of DNA packaging could be a consequence of Brownian movement of the genomic DNA, which would be rectified and harnessed by the forces from the interior wall of the viral channel under the influence of the Donnan effect
Frequency and Severity of Crayfish Injuries as an Indicator of Quality in Channelized Headwater Streams
No full textMany of the agricultural drainage ditches that border farm fields of the Midwestern United States are channelized headwater streams. Despite their degraded state, these ditches support a surprising variety of fish and macroinvertebrate species including crayfish. Crayfish have long been used as model organisms for laboratory studies of aggression, but little is known about their aggressive interactions in the wild. Even less is known about their behavior in channelized headwater streams. Crayfish need different substrates and habitat types at different life stages, and they can be sensitive to the presence of toxic chemicals in the water. In this study eight sites on channelized headwater streams feeding Cedar Creek in Northeastern Indiana, nine sites feeding Upper Big Walnut Creek in Central Ohio, and one site on the East Branch of the Saint Joseph River in Southeastern Michigan were monitored over two years for evidence of crayfish aggression. Crayfish were collected by a combination of electrofishing and seine netting techniques. Individuals were identified to species, sexed, measured, and any damaged appendages were noted as injuries. Data on instream habitat quality were also collected. Concentrations of nutrients and pesticides at all study sites were provided by scientists at the National Soil Erosion Research Laboratory. The mean count of injuries per individual, proportion of injured individuals, mean number of claw injuries per individual, proportion of individuals with multiple injuries, and crayfish density within the sites were calculated. A habitat diversity index and a water toxicity index were developed to assess site quality. A mixed model multiple regression analysis was used to correlate site quality index values with crayfish injury response variables. We found crayfish density to be the major predictor of all the injury response variables, and that habitat and water quality had no significant correlation with crayfish injury or density. Crayfish may not need high quality habitat as defined for other species, beyond what a typical channelized headwater stream can provide. Also, observed concentrations of agrichemicals in the sites were often well below established chronic effect benchmarks. Crayfish are well adapted to life in ditches due to their flexibility in habitat utilization and tolerance of agrichemicals. However, further research is needed to identify factors that determine crayfish community densities.http://opus.ipfw.edu/stu_symp2016/1024/thumbnail.jp
Mysteries of the Cædmon Manuscript, MS. Junius 11
No full texthttp://opus.ipfw.edu/stu_symp2016/1006/thumbnail.jp