3,243 research outputs found
Cure monitoring of a UV cured epoxy resin using a long period grating Mach- Zehnder interferometer
A cascaded long period grating Mach-Zehnder interferometer is used to monitor
the change in refractive index of a UV cured epoxy resin over a cure cycle.
Fourier techniques are used to calculate the phase shift and frequency spectral
amplitude of the associated fringe pattern during the cure. The results are
compared with the refractive index change during cure calculated using a Fresnel
reflection based technique
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Restoration Ecology at 25 years: the editors reflect on how we got here
Seasonal Impacts on Bark Loss for Douglas-fir and Ponderosa Pine Harvested on the Pacific Northwest Coast of the USA
Although only a few harvesting systems today intentionally remove bark prior to transporting logs to the mill, little is known about how much bark is lost during harvesting operations at different times of the year. Depending on where you are located in the forest to mill supply chain, the presence or absence of bark can be seen as a cost or a benefit. Understanding the magnitude of bark loss and the factors that affect it should lead to minimization of the costs and maximization of the benefits.
Quantification of seasonal bark loss (expressed as a percentage of the surface area of the stem) for two commercial tree species was conducted monthly over a 10-month period. All assessments were carried out on Douglas-fir and ponderosa pine harvesting operations that were using mechanized processor heads with chains over rubber feed wheels. Over 400 stems were assessed.
There was a substantial (up to five times) increase in bark loss during late spring and early summer compared with the winter season. We were also able to show that the amount of bark loss is species dependent, with Douglas-fir incurring more than twice the bark loss than found for ponderosa pine. It is possible that the distribution of bark loss along the stem is also species dependent; we found greater bark loss towards the top of the stem in ponderosa pine than towards the bottom of the stem, but no such trend for Douglas-fir
Evolution of mammalian genome organization inferred from comparative gene mapping
Comparative genome analyses, including chromosome painting in over 40 diverse mammalian species, ordered gene maps from several representatives of different mammalian and vertebrate orders, and large-scale sequencing of the human and mouse genomes are beginning to provide insight into the rates and patterns of chromosomal evolution on a whole-genome scale, as well as into the forces that have sculpted the genomes of extant mammalian species
Synergistic antibacterial effects of theaflavin in combination with ampicillin against hospital isolates of Stenotrophomonas Maltophilia
Stenotrophomonas maltophilia is an important opportunistic nosocomial pathogen that shows intrinsic resistance to many antibiotics. This often limits treatment options and can cause lengthy hospital stays. Combination treatments are often used to combat resistance and using natural compounds such as polyphenols could give increased treatment options and even the reuse of antibiotics to which high levels of resistance have been observed. A checkerboard assay was used to determine if any synergy exists between ampicillin and the polyphenol theaflavin against 9 clinical isolates and one control isolate (NCTC 13014) of S. maltophilia. It was discovered that significant synergy (P 0.05) does exist between theaflavin and ampicillin, reducing the mean MIC of ampicillin from 12.5-22.9 µg/mL, in liquid culture, to 3.125-6.25 µg/mL. The FIC index was calculated to be 0.22-0.35 confirming synergy. From these results, significant potential for medical applications can be seen and further investigation is recommended
MECHANISMS FOR ADDRESSING THIRD-PARTY IMPACTS RESULTING FROM VOLUNTARY WATER TRANSFERS
This research uses laboratory experiments to test alternative water market institutions designed to protect third-party interests. The institutions tested include taxing mechanisms that raise revenue to compensate affected third-parties, and a free market in which third-parties actively participate. We also discuss the likely implications of a command-and-control approach in which there are fixed limits on the volume of water that may be exported from a region. The results indicate that there are some important trade-offs in selecting a policy option. Although theoretically optimal, active third-party participation in the market is likely to result in free-riding that may erode some or all of the efficiency gains, and may introduce volatility into the market. Fixed limits on water exports are likely to result in a more stable market, but the constraints on exports will result in lower levels of social welfare. Taxing transfers and compensating third-parties offers a promising balance of efficiency, equity and market stability.Resource /Energy Economics and Policy,
The only known egg of the Night Parrot? A molecular and morphometric assessment of an alleged egg from the Tanami Desert
The Night Parrot Pezoporus occidentalis is a much sought-after, recently ârediscoveredâ, endangered nocturnal parrot, endemic to arid Central Australia. Very little is known of its ecology, and its eggs have never been formally described. The literature on the eggs of the Night Parrot is collated here, and the provenance of an alleged Night Parrot egg found in the Tanami Desert, Northern Territory, in 1983 was assessed using DNA analysis and physical characteristics. Anecdotal reports from the late 19thâearly 20th Century indicate that the Night Parrot lays a clutch of two to six roundish, white eggs. We suggest that its eggs are probably similar to and slightly larger than those of its congener, the Ground Parrot P. wallicus. The alleged Night Parrot egg was definitively identified by mitochondrial DNA analysis to be from the Brown Quail Synoicus ypsilophorus. This represents the first evidence of breeding by this species in the Tanami Desert, and lays to rest a long-standing misconception regarding the parrot
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