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- Creators: Biodesign Institute
- Member of: Programs and Communities
- Status: Published
River rafting trips and hikers use sandbars along the Colorado River in Marble and Grand Canyons as campsites. The U.S. Geological Survey evaluated the effects of Glen Canyon Dam operations on campsite areas on sandbars along the Colorado River in Grand Canyon National Park. Campsite area was measured annually from 1998 to 2012 at 37 study sites between Lees Ferry and Diamond Creek, Arizona. The primary purpose of this report is to present the methods and results of the project.
Campsite area surveys were conducted using total station survey methods to outline the perimeter of camping area at each study site. Campsite area is defined as any region of smooth substrate (most commonly sand) with no more than an 8 degree slope and little or no vegetation. We used this definition, but relaxed the slope criteria to include steeper areas near boat mooring locations where campers typically establish their kitchens.
The results show that campsite area decreased over the course of the study period, but at a rate that varied by elevation zone and by survey period. Time-series plots show that from 1998 to 2012, high stage-elevation (greater than the 25,000 ft3/s stage-elevation) campsite area decreased significantly, although there was no significant trend in low stage-elevation (15,000–20,000 ft3/s) campsite area. High stage-elevation campsite area increased after the 2004 and 2008 high flows, but decreased in the intervals between high flows. Although no overall trend was detected for low stage-elevation campsite areas, they did increase after high-volume dam releases equal to or greater than about 20,000 ft3/s. We conclude that dam operations have not met the management objectives of the Glen Canyon Adaptive Management program to increase the size of camping beaches in critical and non-critical reaches of the Colorado River between Glen Canyon Dam and Lake Mead.
Summary:
Interview conducted by: Dr. Paul Hirt, Arizona southwestern U.S. state. State University and Jennifer Sweeney, Four East Historical Research, LLC. Glen Canyon Dam Adaptive Management Program Administrative History Project. Administered by Arizona southwestern U.S. state. State University Supported by a grant from the US Bureau of Reclamation.
Biography:
Paul Grams has worked directly with the Glen Canyon Dam Adaptive Management Program (GCDAMP) since 2008, as a program manager and research hydrologist at the Grand Canyon Monitoring and Research Center (GCMRC). His involvement in Grand Canyon studies goes back to 1991, when he took a Colorado River research trip as part of an undergraduate science course. Grams is an expert on the effects of dams on river geomorphology and sediment transport. He holds a BA in Geology from Middlebury College, an MS in Geology from Utah State University, and a PhD in Geography and Environmental Engineering from Johns Hopkins University.
Background:
Many pharmaceutical drugs are known to be ineffective or have negative side effects in a substantial proportion of patients. Genomic advances are revealing that some non-synonymous single nucleotide variants (nsSNVs) may cause differences in drug efficacy and side effects. Therefore, it is desirable to evaluate nsSNVs of interest in their ability to modulate the drug response.
Results:
We found that the available data on the link between drug response and nsSNV is rather modest. There were only 31 distinct drug response-altering (DR-altering) and 43 distinct drug response-neutral (DR-neutral) nsSNVs in the whole Pharmacogenomics Knowledge Base (PharmGKB). However, even with this modest dataset, it was clear that existing bioinformatics tools have difficulties in correctly predicting the known DR-altering and DR-neutral nsSNVs. They exhibited an overall accuracy of less than 50%, which was not better than random diagnosis. We found that the underlying problem is the markedly different evolutionary properties between positions harboring nsSNVs linked to drug responses and those observed for inherited diseases. To solve this problem, we developed a new diagnosis method, Drug-EvoD, which was trained on the evolutionary properties of nsSNVs associated with drug responses in a sparse learning framework. Drug-EvoD achieves a TPR of 84% and a TNR of 53%, with a balanced accuracy of 69%, which improves upon other methods significantly.
Conclusions:
The new tool will enable researchers to computationally identify nsSNVs that may affect drug responses. However, much larger training and testing datasets are needed to develop more reliable and accurate tools.
expenditure, and environmental risk. Surfactant treatment to disrupt Scenedesmus biomass was evaluated
as a means to make solvent extraction more efficient. Surfactant treatment increased the recovery of fatty
acid methyl ester (FAME) by as much as 16-fold vs. untreated biomass using isopropanol extraction, and
nearly 100% FAME recovery was possible without any Folch solvent, which is toxic and expensive. Surfactant
treatment caused cell disruption and morphological changes to the cell membrane, as documented by
transmission electron microscopy and flow cytometry. Surfactant treatment made it possible to extract wet
biomass at room temperature, which avoids the expense and energy cost associated with heating
and drying of biomass during the extraction process. The best FAME recovery was obtained from highlipid
biomass treated with Myristyltrimethylammonium bromide (MTAB)- and 3-(decyldimethylammonio)-
propanesulfonate inner salt (3_DAPS)-surfactants using a mixed solvent (hexane : isopropanol = 1 : 1, v/v)
vortexed for just 1 min; this was as much as 160-fold higher than untreated biomass. The critical micelle
concentration of the surfactants played a major role in dictating extraction performance, but the growth
stage of the biomass had an even larger impact on how well the surfactants disrupted the cells and
improved lipid extraction. Surfactant treatment had minimal impact on extracted-FAME profiles and,
consequently, fuel-feedstock quality. This work shows that surfactant treatment is a promising strategy for
more efficient, sustainable, and economical extraction of fuel feedstock from microalgae.
The Combined Activated Sludge-Anaerobic Digestion Model (CASADM) quantifies the effects of recycling anaerobic-digester (AD) sludge on the performance of a hybrid activated sludge (AS)-AD system. The model includes nitrification, denitrification, hydrolysis, fermentation, methanogenesis, and production/utilization of soluble microbial products and extracellular polymeric substances (EPS). A CASADM example shows that, while effluent COD and N are not changed much by hybrid operation, the hybrid system gives increased methane production in the AD and decreased sludge wasting, both caused mainly by a negative actual solids retention time in the hybrid AD. Increased retention of biomass and EPS allows for more hydrolysis and conversion to methane in the hybrid AD. However, fermenters and methanogens survive in the AS, allowing significant methane production in the settler and thickener of both systems, and AD sludge recycle makes methane formation greater in the hybrid system.