2,213 research outputs found
Distribution of Camptotheca Decaisne: Endangered Status
Camptotheca Decaisne is endemic to southern China. Since 1934, C. acuminata has been widely introduced to many gardens and arboreta in North America, Asia, and Europe as living collections. Our national surveys in China between 1995 and 1998 indicated that the genus. Camptotheca spp. are severely endangered in native range. Our field surveys failed to locate any wild populations of C. acuminata although it is often cultivated as landscape trees in southern China. We could not identify any living trees of C. acuminata var. tenuifolia and var. rotundifolia. We estimated that there are approximately 500 mature trees of C. lowreyana in Guangdong and less than 50 wild mature trees of C. yunnanensis in Yunnan
Temporal and Spatial Analysis of Water Quality and Landscape Characteristics for Albemarle Sound, North Carolina
Albemarle Sound, a lagoonal estuarine system on the North Carolina coast, has experienced a large decline in recreational and commercial fisheries over the years and managers are concerned about water quality, including the impacts of nutrient enrichment, or eutrophication. In an effort to help the United States Geological Survey improve its water quality monitoring network, this report compiles and analyzes over 40 years of historic data for the sound using three approaches.
Based on the current monitoring program and available historic data collected, five chemical and biological water quality parameters were chosen to characterize the water quality in Albemarle Sound: chlorophyll-a (Chl-a), dissolved oxygen (DO), turbidity, inorganic nitrogen (nitrate and nitrate) as N and phosphate-phosphorus as P. This project 1) statistically analyzes the relationships between water quality parameters within and among sub-sections of the Sound; 2) combines multiple sources of LULC data into sub-sections to better understand water quality drivers; 3) develops a GIS-based user interactive toolkit to identify the sensitive location(s).
Statistical and geospatial analyses show: 1) Overall, water quality in Albemarle Sound is good over time. 2) Seasonal effects may influence parameter values in some parts of the sound. 3) In light of inorganic nitrogen and phosphate-phosphorus levels, we may pay more attention to the North and South sections, as these two sections were more vulnerable to nutrient problems in history. 4) There are major differences in landscape characteristics between sections, offering some explanation for differences in water quality, and 5) There are some signals in the average concentrations of the five water quality parameters from 2006-2013, indicating that terrestrial drivers such as CAFO animal density and percent cultivated area could be important for water quality in the Albemarle Sound. This report provides fundamental guidance that can be used to inform both management plans and future studies in Albemarle Sound
The cAMP-Dependent Protein Kinase Inhibitor H-89 Attenuates the Bioluminescence Signal Produced by Renilla Luciferase
Investigations into the regulation and functional roles of kinases such as cAMP-dependent protein kinase (PKA) increasingly rely on cellular assays. Currently, there are a number of bioluminescence-based assays, for example reporter gene assays, that allow the study of the regulation, activity, and functional effects of PKA in the cellular context. Additionally there are continuing efforts to engineer improved biosensors that are capable of detecting real-time PKA signaling dynamics in cells. These cell-based assays are often utilized to test the involvement of PKA-dependent processes by using H-89, a reversible competitive inhibitor of PKA.We present here data to show that H-89, in addition to being a competitive PKA inhibitor, attenuates the bioluminescence signal produced by Renilla luciferase (RLuc) variants in a population of cells and also in single cells. Using 10 microM of luciferase substrate and 10 microM H-89, we observed that the signal from RLuc and RLuc8, an eight-point mutation variant of RLuc, in cells was reduced to 50% (+/-15%) and 54% (+/-14%) of controls exposed to the vehicle alone, respectively. In vitro, we showed that H-89 decreased the RLuc8 bioluminescence signal but did not compete with coelenterazine-h for the RLuc8 active site, and also did not affect the activity of Firefly luciferase. By contrast, another competitive inhibitor of PKA, KT5720, did not affect the activity of RLuc8.The identification and characterization of the adverse effect of H-89 on RLuc signal will help deconvolute data previously generated from RLuc-based assays looking at the functional effects of PKA signaling. In addition, for the current application and future development of bioluminscence assays, KT5720 is identified as a more suitable PKA inhibitor to be used in conjunction with RLuc-based assays. These principal findings also provide an important lesson to fully consider all of the potential effects of experimental conditions on a cell-based assay readout before drawing conclusions from the data
Transcriptional profiling avian beta-defensins in chicken oviduct epithelial cells before and after infection with Salmonella enterica serovar Enteritidis
<p>Abstract</p> <p>Background</p> <p><it>Salmonella enterica </it>serovar Enteritidis (SE) colonizes the ovary and oviduct of chickens without causing overt clinical signs which can lead to SE-contamination of the content and membrane of shell-eggs as well as hatchery eggs. The organism utilizes the <it>Salmonella </it>Pathogenicity Island-2 encoded type III secretion system (T3SS-2) to promote persistence in the oviduct of laying hens. In this study, reverse transcriptase-polymerase chain reaction (RT-PCR) was carried out to determine the expression profiles of 14 known avian beta defensins (AvBDs) in primary chicken oviduct epithelial cells (COEC) before and after infections with a wild type SE strain and T3SS mutant SE strains carrying an inactivated <it>sipA </it>or <it>pipB </it>gene.</p> <p>Results</p> <p>Based on the expression levels in uninfected COEC, AvBDs can be loosely grouped into three categories with AvBD4-5 and AvBD9-12 being constitutively expressed at high levels; AvBD1, AvBD3, and AvBD13-14 at moderate levels; and AvBD2 and AvBD6-8 at minimal levels. Infection with the wild type SE strain temporarily repressed certain highly expressed AvBDs and induced the expression of minimally expressed AvBDs. The <it>pipB </it>mutant, compared to the wild type strain, had reduced suppressive effect on the expression of highly expressed AvBDs. Moreover, the <it>pipB </it>mutant elicited significantly higher levels of the minimally expressed AvBDs than the wild type SE or the <it>sipA </it>mutant did.</p> <p>Conclusion</p> <p>Chicken oviduct epithelial cells express most of the known AvBD genes in response to SE infection. PipB, a T3SS-2 effector protein, plays a role in dampening the β-defensin arm of innate immunity during SE invasion of chicken oviduct epithelium.</p
Sediment chemistry in a hydrologically restored bottomland hardwood forest in Midwestern US
The University Archives has determined that this item is of continuing value to OSU's history
Municipal investment in off-road trails and changes in bicycle commuting in Minneapolis, Minnesota over 10Â years: a longitudinal repeated cross-sectional study
Abstract Background We studied the effect of key development and expansion of an off-road multipurpose trail system in Minneapolis, Minnesota between 2000 and 2007 to understand whether infrastructure investments are associated with increases in commuting by bicycle. Methods We used repeated measures regression on tract-level (N = 116 tracts) data to examine changes in bicycle commuting between 2000 and 2008–2012. We investigated: 1) trail proximity measured as distance from the trail system and 2) trail potential use measured as the proportion of commuting trips to destinations that might traverse the trail system. All analyses (performed 2015–2016) adjusted for tract-level sociodemographic covariates and contemporaneous cycling infrastructure changes (e.g., bicycle lanes). Results Tracts that were both closer to the new trail system and had a higher proportion of trips to destinations across the trail system experienced greater 10-year increases in commuting by bicycle. Conclusions Proximity to off-road infrastructure and travel patterns are relevant to increased bicycle commuting, an important contributor to overall physical activity. Municipal investment in bicycle facilities, especially off-road trails that connect a city’s population and its employment centers, is likely to lead to increases in commuting by bicycle
Multi-Task Imitation Learning for Linear Dynamical Systems
We study representation learning for efficient imitation learning over linear
systems. In particular, we consider a setting where learning is split into two
phases: (a) a pre-training step where a shared -dimensional representation
is learned from source policies, and (b) a target policy fine-tuning step
where the learned representation is used to parameterize the policy class. We
find that the imitation gap over trajectories generated by the learned target
policy is bounded by , where is the state
dimension, is the input dimension, denotes the
total amount of data collected for each policy during representation learning,
and is the amount of target task data. This result
formalizes the intuition that aggregating data across related tasks to learn a
representation can significantly improve the sample efficiency of learning a
target task. The trends suggested by this bound are corroborated in simulation.Comment: Appeared in L4DC 2023. V3: corrected typo in assumption
Hybrid Computing for Interactive Datacenter Applications
Field-Programmable Gate Arrays (FPGAs) are more energy efficient and cost
effective than CPUs for a wide variety of datacenter applications. Yet, for
latency-sensitive and bursty workloads, this advantage can be difficult to
harness due to high FPGA spin-up costs. We propose that a hybrid FPGA and CPU
computing framework can harness the energy efficiency benefits of FPGAs for
such workloads at reasonable cost. Our key insight is to use FPGAs for
stable-state workload and CPUs for short-term workload bursts. Using this
insight, we design Spork, a lightweight hybrid scheduler that can realize these
energy efficiency and cost benefits in practice. Depending on the desired
objective, Spork can trade off energy efficiency for cost reduction and vice
versa. It is parameterized with key differences between FPGAs and CPUs in terms
of power draw, performance, cost, and spin-up latency. We vary this parameter
space and analyze various application and worker configurations on production
and synthetic traces. Our evaluation of cloud workloads shows that
energy-optimized Spork is not only more energy efficient but it is also cheaper
than homogeneous platforms--for short application requests with tight
deadlines, it is 1.53x more energy efficient and 2.14x cheaper than using only
FPGAs. Relative to an idealized version of an existing cost-optimized hybrid
scheduler, energy-optimized Spork provides 1.2-2.4x higher energy efficiency at
comparable cost, while cost-optimized Spork provides 1.1-2x higher energy
efficiency at 1.06-1.2x lower cost.Comment: 13 page
- …