253 research outputs found
Production and Cost Assessment of a Potential Application of Surface Miners in Coal Mining in West Virginia
The broad objective of this research was to improve current mining practices and reduce negative environmental impact of surface coal mining in West Virginia (WV). The specific objectives were to (i) build the production and cost models to determine if conventional surface mining unit operations such as drilling, blasting, digging, loading, and crushing can be replaced with one mining machine called a surface miner (SM), (ii) apply the analytical hierarchy process (AHP) to help select the optimal mining method, and (iii) determine the extent of which the SM would benefit surface coal mining in WV, particularly by reducing some of the negative environmental impacts associated with current extraction practices.;The entire production and cost models were developed in MS Excel. The design and the procedures used for achieving the objectives involved six interrelated modules. Module #1 includes rock properties of sandstone, shale, which are the predominant overburden and interburden materials in WV, and sub-bituminous coal. Module #2 considers drilling and blasting operations. Module #3 includes digging and loading of overburden material. It specifically addresses mining equipment such as electric and hydraulic shovels and front-end wheel loaders. Interburden material also includes sandstone and shale, and the two unit operations involved are ripping and pushing by bulldozers and loading by hydraulic backhoe shovel. Module #4 covers coal extraction by hydraulic backhoe shovel and the crushing operation. Module #5 focuses on the SM, while Module #6 is used to conduct comparative analyses among all mining unit operations for overburden, interburden, and coal. The resulting production rates, ownership, and operating costs were also presented. The analytical hierarchy process (AHP) was used to help select the optimal mining method based on both qualitative and quantitative factors.;Based on the results of this research, application of SM would benefit coal extraction in surface mining operations in WV. The estimated cost of coal extraction is lower than with conventional mining methods, and the machine is able to work selectively with high separation accuracy. Thin seams of coal and overburden can be mined separately, thus preventing dilution with interburden material. Rising operating costs for the SM become an issue as the quantity of material being extracted increases and higher values of unconfined compressive strength are encountered. Cutting tools on the drum wear out faster and require more changes and, at a certain point, the SM becomes unfeasible because of the time and cost involved in changing cutting tools. A significant advantage of SM, where applicable, is the elimination of the negative environmental impacts associated with blasting
Mutational and transcriptional analyses of an avian pathogenic Escherichia coli ColV plasmid
<p>Abstract</p> <p>Background</p> <p>Previously we described a 184-kb ColV plasmid, pAPEC-O2-ColV, that contributed to the ability of an <it>E. coli </it>to kill avian embryos, grow in human urine, and colonize the murine kidney. Here, the roles of several genes encoded by this plasmid in virulence were assessed using mutational and transcriptional analyses.</p> <p>Methods</p> <p>Genes chosen for deletion were <it>iss</it>, <it>tsh</it>, <it>iutA</it>, <it>iroN</it>, <it>sitA</it>, and <it>cvaB</it>. In addition, a 35-kb region of the plasmid, containing <it>iss</it>, <it>tsh</it>, and the ColV and <it>iro </it>operons, along with a 15-kb region containing both the aerobactin and <it>sit </it>operons, were deleted. Mutants were compared to the wild-type (APEC O2) for lethality to chick embryos and growth in human urine. Expression of the targeted genes was also assessed under these same conditions using RT-PCR</p> <p>Results</p> <p>No significant differences between the mutants and the wild-type in these phenotypic traits were detected. However, genes encoding known or predicted iron transport systems were up-regulated during growth in human urine, as compared to growth in LB broth, while <it>iss</it>, <it>hlyF</it>, and <it>iroN </it>were strongly up-regulated in chick embryos.</p> <p>Conclusion</p> <p>While no difference was observed between the mutant strains and their wild-type parent in the phenotypic traits assayed, we reasoned that some compensatory virulence mechanism, insensitivity of the virulence assays, or other factor could have obscured changes in the virulence of the mutants. Indeed we found several of these genes to be up-regulated in human urine and/or in the chick embryo, suggesting that certain genes linked to ColV plasmids are involved in the establishment of avian extraintestinal infection.</p
Properties of Nearby Starburst Galaxies Based on their Diffuse Gamma-ray Emission
The physical relationship between the far-infrared and radio fluxes of star
forming galaxies has yet to be definitively determined. The favored
interpretation, the "calorimeter model," requires that supernova generated
cosmic ray (CR) electrons cool rapidly via synchrotron radiation. However, this
cooling should steepen their radio spectra beyond what is observed, and so
enhanced ionization losses at low energies from high gas densities are also
required. Further, evaluating the minimum energy magnetic field strength with
the traditional scaling of the synchrotron flux may underestimate the true
value in massive starbursts if their magnetic energy density is comparable to
the hydrostatic pressure of their disks. Gamma-ray spectra of starburst
galaxies, combined with radio data, provide a less ambiguous estimate of these
physical properties in starburst nuclei. While the radio flux is most sensitive
to the magnetic field, the GeV gamma-ray spectrum normalization depends
primarily on gas density. To this end, spectra above 100 MeV were constructed
for two nearby starburst galaxies, NGC 253 and M82, using Fermi data. Their
nuclear radio and far-infrared spectra from the literature are compared to new
models of the steady-state CR distributions expected from starburst galaxies.
Models with high magnetic fields, favoring galaxy calorimetry, are overall
better fits to the observations. These solutions also imply relatively high
densities and CR ionization rates, consistent with molecular cloud studies.Comment: Accepted to Ap
Facing the River Gauntlet: Understanding the Effects of Fisheries Capture and Water Temperature on the Physiology of Coho Salmon
An improved understanding of bycatch mortality can be achieved by complementing field studies with laboratory experiments that use physiological assessments. This study examined the effects of water temperature and the duration of net entanglement on physiological disturbance and recovery in coho salmon (Oncorhynchus kisutch) after release from a simulated beach seine capture. Heart rate was monitored using implanted electrocardiogram biologgers that allowed fish to swim freely before and after release. A subset of fish was recovered in respirometers to monitor metabolic recovery, and separate groups of fish were sacrificed at different times to assess blood and white muscle biochemistry. One hour after release, fish had elevated lactate in muscle and blood plasma, depleted tissue energy stores, and altered osmoregulatory status, particularly in warmer (15 vs. 10Ā°C) and longer (15 vs. 2 min) capture treatments. A significant effect of entanglement duration on blood and muscle metabolites remained after 4 h. Oxygen consumption rate recovered to baseline within 7ā10 h. However, recovery of heart rate to routine levels was longer and more variable, with most fish taking over 10 h, and 33% of fish failing to recover within 24 h. There were no significant treatment effects on either oxygen consumption or heart rate recovery. Our results indicate that fishers should minimize handling time for bycatch and maximize oxygen supply during crowding, especially when temperatures are elevated. Physiological data, such as those presented here, can be used to understand mechanisms that underlie bycatch impairment and mortality, and thus inform best practices that ensure the welfare and conservation of affected species
Protocol for a randomised controlled trial of a family strengthening program to prevent unhealthy weight gain among 5 to 11-year-old children from at-risk families : the Strong Families Trial
Background: Obesity is an increasing health concern in Australia among adult and child populations alike and is often associated with other serious comorbidities. While the rise in the prevalence of childhood obesity has plateaued in high-income countries, it continues to increase among children from disadvantaged and culturally diverse backgrounds. The family environment of disadvantaged populations may increase the risk of childhood obesity through unhealthy eating and lifestyle practices. The Strong Families Trial aims to assess the effectiveness of a mixed behavioural and lifestyle intervention for parents and carers of at-risk populations, i.e. families from culturally diverse and disadvantaged backgrounds, in preventing unhealthy weight gain among children aged 5 to 11 years. Methods: Eight hundredĀ families from low socio-economic areas in Greater Western Sydney, NSW, and Melbourne, VIC, will be recruited and randomised into aĀ lifestyleĀ intervention or control group. The intervention comprises 90-minute weekly sessions for 6 weeks (plus two-booster sessions) of an integrated, evidence-based, parenting and lifestyle program that accounts for the influences of family functioning. Primary (anthropometric data) and secondary (family functioning, feeding related parenting, physical activity, consumption of healthy foods, health literacy, family and household costs) outcome measures will be assessed at baseline, immediately following the intervention, and 12 months post-intervention. Discussion: This study will elucidate methods for engaging socially disadvantaged and culturally diverse groups in parenting programs concerned with child weight status. Trial Registration: This study is registered with the Australian New Zealand Clinical Trials Registry (ACTRN12619001019190). Registered 16 July 2019
Highly stable PEGylated gold nanoparticles in water: applications in biology and catalysis
Here we report the synthesis of well dispersed gold nanoparticles (Au NPs), with diameters ranging between 5 and 60 nm, in water and demonstrate their potential usefulness in catalysis and biological applications. Functionalised polyethylene glycol-based thiol polymers (mPEG-SH) were used to stabilise the pre-synthesised NPs. Successful PEGylation of the NPs was confirmed by Dynamic Light Scattering (DLS) and zeta potential measurements. PEG coating of the NPs was found to be key to their colloidal stability in high ionic strength media, compared to bare citrate-stabilised NPs. Our results show that PEGāAu NPs with diameters <30 nm were useful as catalysts in the homocoupling of arylboronic acids in water. Additionally, PEGāAu NPs were also shown to be stable in biological fluids, non-cytotoxic to B16.F10 and CT-26 cell lines and able to successfully deliver siRNA to CT-26 cells, achieving a significant reduction (p < 0.05) in the expression levels of luciferase protein; making these NPs attractive for further biological studies
PheMaDB: A solution for storage, retrieval, and analysis of high throughput phenotype data
<p>Abstract</p> <p>Background</p> <p>OmniLogā¢ phenotype microarrays (PMs) have the capability to measure and compare the growth responses of biological samples upon exposure to hundreds of growth conditions such as different metabolites and antibiotics over a time course of hours to days. In order to manage the large amount of data produced from the OmniLogā¢ instrument, PheMaDB (Phenotype Microarray DataBase), a web-based relational database, was designed. PheMaDB enables efficient storage, retrieval and rapid analysis of the OmniLogā¢ PM data.</p> <p>Description</p> <p>PheMaDB allows the user to quickly identify records of interest for data analysis by filtering with a hierarchical ordering of Project, Strain, Phenotype, Replicate, and Temperature. PheMaDB then provides various statistical analysis options to identify specific growth pattern characteristics of the experimental strains, such as: outlier analysis, negative controls analysis (signal/background calibration), bar plots, pearson's correlation matrix, growth curve profile search, <it>k</it>-means clustering, and a heat map plot. This web-based database management system allows for both easy data sharing among multiple users and robust tools to phenotype organisms of interest.</p> <p>Conclusions</p> <p>PheMaDB is an open source system standardized for OmniLogā¢ PM data. PheMaDB could facilitate the banking and sharing of phenotype data. The source code is available for download at <url>http://phemadb.sourceforge.net</url>.</p
Genome sequencing provides insight into the reproductive biology, nutritional mode and ploidy of the fern pathogen M ixia osmundae
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106716/1/nph12653.pd
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