683 research outputs found
Investigation of Metal and Organic Contaminant Distributions and Sedimentation Rates in Backwater Lakes along the Illinois River
Systematic sub-sampling of sediment cores in sections of uniform thickness is necessary
in order to evaluate historic changes in sediment quality, to determine the vertical extent
of contamination, and to measure sedimentation rates. With these objectives in mind,
fourteen sediment cores were collected during March 2002 using the Illinois State Water
Survey vibracorer. Concentrations of metals and total organic carbon were measured
using standard techniques. Concentrations of chlorinated pesticides, phenolic compounds,
polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs) were
measured by gas chromatography/mass spectrometry (GC-MS). The concentrations of
chlorinated pesticides, phenolic compounds and polychlorinated biphenyls (PCBs) were
below the method detection limit in all sediment samples analyzed. However, there was
a wide range in concentrations of polycyclic aromatic hydrocarbons (PAHs) which were
detected in all sediment samples. Also, a wide range of metal concentrations was noted
in the sediments evaluated. Lower concentrations of metals were found in the upper 0.5
m of sediment but concentrations were elevated at depths ranging from 1.0 m to 1.5 m.
Sedimentation rates were estimated using cesium-137 radiometric dating on 14
vibracores. Sedimentation rates range from < 0.1 to 1.9 cm/yr, with an average of 0.9
cm/yr. These rates are comparable to those reported in previous studies.Illinois Sustainable Technology Centerpublished or submitted for publicationis peer reviewe
Feasibility of Commercial Fishing Operations in the Mid-Atlantic Continental Slope
The objective of the project was to test the feasibility of conducting commercial trawling operations in the slope waters ( 100 fm-300 fm) adjacent to the traditional fishing areas on the continental shelf in the Mid-Atlantic Bight. This was to be accomplished by developing a fishing strategy that would be structured around existing information on stock abundance, type and location and implementing the fishing strategy by procuring a lease on a commercial fishing vessel that would be suitable for slope trawling. The implementation of fishery operations would be the primary goal of the project and every effort would be made to conduct the exploratory trips as a commercial trawling endeavour
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Whole-genome sequence analysis shows that two endemic species of North American wolf are admixtures of the coyote and gray wolf.
Protection of populations comprising admixed genomes is a challenge under the Endangered Species Act (ESA), which is regarded as the most powerful species protection legislation ever passed in the United States but lacks specific provisions for hybrids. The eastern wolf is a newly recognized wolf-like species that is highly admixed and inhabits the Great Lakes and eastern United States, a region previously thought to be included in the geographic range of only the gray wolf. The U.S. Fish and Wildlife Service has argued that the presence of the eastern wolf, rather than the gray wolf, in this area is grounds for removing ESA protection (delisting) from the gray wolf across its geographic range. In contrast, the red wolf from the southeastern United States was one of the first species protected under the ESA and was protected despite admixture with coyotes. We use whole-genome sequence data to demonstrate a lack of unique ancestry in eastern and red wolves that would not be expected if they represented long divergent North American lineages. These results suggest that arguments for delisting the gray wolf are not valid. Our findings demonstrate how a strict designation of a species under the ESA that does not consider admixture can threaten the protection of endangered entities. We argue for a more balanced approach that focuses on the ecological context of admixture and allows for evolutionary processes to potentially restore historical patterns of genetic variation
Draft Report: Sediment Characterization in the Middle Peoria Pool, Illinois River
The Illinois Waterway (IWW) is a significant resource to the state of Illinois and the nation as a whole. Commercial navigation on the Illinois Waterway provides a vital means for transporting commodities to and from blue water ports on the East and Gulf coasts of the United States. However throughout the world large floodplain-river ecosystems, like the Illinois River, are becoming increasingly rare. The National Research Council Committee on Aquatic Ecosystems considered this ecosystem type to be the highest priority for aquatic restoration and specifically named the Illinois River as one of three floodplain-river ecosystems within the United States having sufficient ecological integrity to recover. To address the concomitant while sometimes competing needs of commercial navigation and ecological integrity the US federal government, through the Army Corp of Engineers (COE), and the Upper Mississippi River states have proposed the Navigation and Ecological Sustainability Project (NESP) as a means of improving navigation along the Upper Mississippi and Illinois Waterways while improving and/or mitigating the environmental impacts associated with the navigation improvements. As part of this effort it is envisioned that certain backwater areas within the middle Peoria Pool area will be dredged and the dredged material will be used for the construction of islands, elevated floodplain areas or other beneficial uses. These deep water areas will provide suitable overwinter habitat for native fish species while the islands and elevated floodplain areas will diversify terrestrial habitats within that river reach and provide loafing and nesting habitat for waterfowl and shorebirds.
These Options 1-3 of this project seek to provide additional data to help further characterize the sediments found in the middle reach of the Illinois River. For this project that area can generally be described as that portion of the Illinois River between Lacon and Chillicothe IL. The descriptions, photos, and analytical results of the analyses for the 16
sediment cores collected May 8-9, 2006 are presented.U.S. Army Corps of Engineers, Rock Island DistrictResults for Contract Options 1-3........................................................................... 1
Introduction ............................................................. 1
Acknowledgments ................................................... 1
Study Area ............................................................. 1
Methods .................................................................. 3
Results ................................................................... 4
References ............................................................ 5
Results for Contract Base Option .......................... 7
Appendix A. Field Sheets ....................................... 48
Appendix B. Standard Operating Procedures for the Collection of Sediment Cores Using the Rossfelder 3-Pc Vibrocore ............. 54
Appendix C. Chemical Results from Severn Trent Laboratories ..........62
Appendix D. Particle Size Results ............................................... 195
Appendix E. Percent Moisture ................................................... 230
Appendix F. Photographs of Sediment Cores ............................ 234Ope
Not a melting pot: Plant species aggregate in their non-native range
Aim Plant species continue to be moved outside of their native range by human activities. Here, we aim to determine whether, once introduced, plants assimilate into native communities or whether they aggregate, thus forming mosaics of native- and alien-rich communities. Alien species might aggregate in their non-native range owing to shared habitat preferences, such as their tendency to establish in high-biomass, species-poor areas. Location Twenty-two herbaceous grasslands in 14 countries, mainly in the temperate zone. Time period 2012-2016. Major taxa studied Plants. Methods We used a globally coordinated survey. Within this survey, we found 46 plant species, predominantly from Eurasia, for which we had co-occurrence data in their native and non-native ranges. We tested for differences in co-occurrence patterns of 46 species between their native (home) and non-native (away) range. We also tested whether species had similar habitat preferences, by testing for differences in total biomass and species richness of the patches that species occupy in their native and non-native ranges. Results We found the same species to show different patterns of association depending on whether they were in their native or non-native range. Alien species were negatively associated with native species; instead, they aggregated with other alien species in species-poor, high-biomass communities in their non-native range compared with their native range. Main conclusions The strong differences between the native (home) and non-native (away) range in species co-occurrence patterns are evidence that the way in which species associate with resident communities in their non-native range is not species dependent, but is instead a property of being away from their native range. These results thus highlight that species might undergo important ecological changes when introduced away from their native range. Overall, we show origin-dependent associations that result in novel communities, in which alien-rich patches exist within a mosaic of native-dominated communities
Direct ink writing of ultra-high temperature ceramics
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Electropermanent magnetic anchoring for surgery and endoscopy
The use of magnets for anchoring of instrumentation in minimally invasive surgery and endoscopy has become of increased interest in recent years. Permanent magnets have significant advantages over electromagnets for these applications; larger anchoring and retraction force for comparable size and volume without the need for any external power supply. However, permanent magnets represent a potential hazard in the operating field where inadvertent attraction to surgical instrumentation is often undesirable. The current work proposes an interesting hybrid approach which marries the high forces of permanent magnets with the control of electromagnetic technology including the ability to turn the magnet OFF when necessary. This is achieved through the use of an electropermanent magnet, which is designed for surgical retraction across the abdominal and gastric walls. Our electropermanent magnet, which is hand-held and does not require continuous power, is designed with a center lumen which may be used for trocar or needle insertion. The device in this application has been demonstrated successfully in the porcine model where coupling between an intraluminal ring magnet and our electropermanent magnet facilitated guided insertion of an 18 Fr Tuohy needle for guidewire placement. Subsequent investigations have demonstrated the ability to control the coupling distance of the system alleviating shortcomings with current methods of magnetic coupling due to variation in transabdominal wall thicknesses. With further refinement, the magnet may find application in the anchoring of endoscopic and surgical instrumentation for minimally invasive interventions in the gastrointestinal tract
Childhood and the politics of scale: Descaling children's geographies?
This is the post-print version of the final published paper that is available from the link below. Copyright @ 2008 SAGE Publications.The past decade has witnessed a resurgence of interest in the geographies of children's lives, and particularly in engaging the voices and activities of young people in geographical research. Much of this growing body of scholarship is characterized by a very parochial locus of interest — the neighbourhood, playground, shopping mall or journey to school. In this paper I explore some of the roots of children's geographies' preoccupation with the micro-scale and argue that it limits the relevance of research, both politically and to other areas of geography. In order to widen the scope of children's geographies, some scholars have engaged with developments in the theorization of scale. I present these arguments but also point to their limitations. As an alternative, I propose that the notion of a flat ontology might help overcome some difficulties around scalar thinking, and provide a useful means of conceptualizing sociospatiality in material and non-hierarchical terms. Bringing together flat ontology and work in children's geographies on embodied subjectivity, I argue that it is important to examine the nature and limits of children's spaces of perception and action. While these spaces are not simply `local', they seldom afford children opportunities to comment on, or intervene in, the events, processes and decisions that shape their own lives. The implications for the substance and method of children's geographies and for geographical work on scale are considered
Routine Left Ventricular Pacing for Patients Undergoing Transcatheter Aortic Valve Replacement
ABSTRACTBackground: Rapid ventricular pacing is often required during transcatheter aortic valve replacement (TAVR) procedures. Pacing via the retrograde left ventricular guidewire (LV-GW) is an al..
Survival and divergence in a small group: The extraordinary genomic history of the endangered Apennine brown bear stragglers
About 100 km east of Rome, in the central Apennine Mountains, a critically endangered population of ∼50 brown bears live in complete
isolation. Mating outside this population is prevented by several 100 km of bear-free territories. We exploited this natural
experiment to better understand the gene and genomic consequences of surviving at extremely small population size. We found
that brown bear populations in Europe lost connectivity since Neolithic times, when farming communities expanded and forest burning
was used for land clearance. In central Italy, this resulted in a 40-fold population decline. The overall genomic impact of this decline
included the complete loss of variation in the mitochondrial genome and along long stretches of the nuclear genome. Several private and
deleterious amino acid changes were fixed by random drift; predicted effects include energy deficit, muscle weakness, anomalies
in cranial and skeletal development, and reduced aggressiveness. Despite this extreme loss of diversity, Apennine bear genomes show
nonrandom peaks of high variation, possibly maintained by balancing selection, at genomic regions significantly enriched for genes
associated with immune and olfactory systems. Challenging the paradigm of increased extinction risk in small populations, we suggest
that random fixation of deleterious alleles (i) can be an important driver of divergence in isolation, (ii) can be tolerated when balancing
selection prevents random loss of variation at important genes, and (iii) is followed by or results directly in favorable behavioral changes
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