Continuous variable quantum key distribution with multi-mode signals for noisy detectors

This paper proposes a multi-mode Gaussian modulated continuous variable quantum key distribution (CV-QKD) scheme able to operate at high bandwidth despite using conventional noisy, coherent detectors. We demonstrate enhancement in shotnoise sensitivity as well as reduction in the electronic noise variance of the coherent receiver of the multi-mode CV-QKD system. A proof-of-concept simulation is presented using multiple modes; this demonstrates an increase in signal-to-noise ratio and secure key rate at various transmission distances with increasing signal modes

Integrated management of invasive cattails (Typha spp.) for wetland habitat and biofuel in the Northern Great Plains of the United States and Canada: A review

On many public lands in the Great Plains region of the USA and Canada, cattail (Typha spp.) growth has far exceeded the 50:50 distribution recommended for optimum wetland wildlife habitat. Excessive cattail growth is the primary concern of wetland managers and its integrated management is reviewed here. The coverage of this mostly hybrid cattail (T. latifolia × T. angustifolia) is often over 90 % and if partially removed for habitat enhancement represents a substantial biomass resource in sites such as conservation wetlands, water retention basins and roadside drainage ditches. Available biomass is estimated to be 3,000 kg/ha assuming a 50 % harvest rate. Cattail control using mowing, herbicides, and burning is expensive, therefore if harvest logistics can be improved along with developing biomass markets, harvest management would become much more viable. Energy values of cattails are comparable to wood pellets at 20 MJ/kg. Cattails can be simultaneously managed for wetland wildlife, harvested for biofuel, serve as a partial substitute for coal, generate carbon credits, and remove phosphorus from the watershed. Cattails extract nitrogen and phosphorous from runoff water that enters rivers and lakes that could be used for agricultural fertiliser while reducing eutrophication. Additionally, rural economies could be boosted by harvesting a renewable energy resource, especially in areas with little fossil fuels or unsustainable biomass practices

Typha (Cattail) Invasion in North American Wetlands: Biology, Regional Problems, Impacts, Ecosystem Services, and Management

Typha is an iconic wetland plant found worldwide. Hybridization and anthropogenic disturbances have resulted in large increases in Typha abundance in wetland ecosystems throughout North America at a cost to native floral and faunal biodiversity. As demonstrated by three regional case studies, Typha is capable of rapidly colonizing habitats and forming monodominant vegetation stands due to traits such as robust size, rapid growth rate, and rhizomatic expansion. Increased nutrient inputs into wetlands and altered hydrologic regimes are among the principal anthropogenic drivers of Typha invasion. Typha is associated with a wide range of negative ecological impacts to wetland and agricultural systems, but also is linked with a variety of ecosystem services such as bioremediation and provisioning of biomass, as well as an assortment of traditional cultural uses. Numerous physical, chemical, and hydrologic control methods are used to manage invasive Typha, but results are inconsistent and multiple methods and repeated treatments often are required. While this review focuses on invasive Typha in North America, the literature cited comes from research on Typha and other invasive species from around the world. As such, many of the underlying concepts in this review are relevant to invasive species in other wetland ecosystems worldwide

Transition-state discrimination by adenosine deaminase from Aspergillus oryzae

Adenosine deaminase from Aspergillus oryzae resembles mammalian adenosine deaminases in its ability to catalyze the hydrolytic removal of many substituents from C-6, and in the chirality at C-6 of the active isomer of the transition-state-analogue inhibitor 6-hydroxymethyl-l,6-dihydropurine ribonucleoside. The 5'-OH group of adenosine has been found to contribute a factor of 5 • 10 4 to transition-state stabilization by calf intestinal adenosine deaminase, and crystallographic observations suggest that a zinc-histidine 'bridge' is formed between the 6-OH and the 5'-OH groups of the substrate in the transition state for its deamination. The present paper describes experiments indicating that this bridge is not present during the action of adenosine deaminase from Aspergillus oryzae. We find (1), that the fungal enzyme catalyzes deamination of adenosine and 5'-deoxyadenosine with kcat/Km values that are almost identical; (2), that the K i value of the transition-state-analogue inhibitor 2'-deoxycoformycin is much higher for the fungal enzyme (2.7.10 -9 M) than for the mammalian enzyme (2-10 12 M) and (3), that this difference in binding affinities arises mainly from a difference in rates of enzyme-inhibitor association. Thus, the onset of inhibition was markedly slower for the fungal enzyme (kon = 1.3 • 104 M-l s-1) than for the calf intestinal enzyme (kon = 2.6.106 M i s-l). Effects of chelating agents and divalent cations suggest that the fungal enzyme, like other deaminases for adenosine and cytidine, contains essential zinc

Glyphosate (Ab)sorption by Shoots and Rhizomes of Native versus Hybrid Cattail (Typha)

Wetlands in the Prairie Pothole Region of North America are integrated with farmland and contain mixtures of herbicide contaminants. Passive nonfacilitated diffusion is how most herbicides can move across plant membranes, making this perhaps an important process by which herbicide contaminants are absorbed by wetland vegetation. Prairie wetlands are dominated by native cattail (Typha latifolia) and hybrid cattail (Typha x glauca). The objective of this batch equilibrium study was to compare glyphosate absorption by the shoots and rhizomes of native versus hybrid cattails. Although it has been previously reported for some pesticides that passive diffusion is greater for rhizome than shoot components, this is the first study to demonstrate that the absorption capacity of rhizomes is species dependent, with the glyphosate absorption being significantly greater for rhizomes than shoots in case of native cattails, but with no significant differences in glyphosate absorption between rhizomes and shoots in case of hybrid cattails. Most importantly, glyphosate absorption by native rhizomes far exceeded that of the absorption occurring for hybrid rhizomes, native shoots and hybrid shoots. Glyphosate has long been used to manage invasive hybrid cattails in wetlands in North America, but hybrid cattail expansions continue to occur. Since our results showed limited glyphosate absorption by hybrid shoots and rhizomes, this lack of sorption may partially explain the poorer ability of glyphosate to control hybrid cattails in wetlands