Mycorrhizas for a changing world: Sustainability, conservation, and society

Mycorrhizal fungi, of all types, hold huge significance for our planet and society. By forming mutualistic symbioses with the vast majority of land plants, mycorrhizas play an essential role in the formation and maintenance of global ecosystems. They also have great potential for exploitation to facilitate a variety of sustainability programs in agriculture, conservation, and restoration, particularly relevant in the context of global climate change and depletion of natural resources. As such, in addition to the fruiting bodies of many mycorrhiza‐forming fungal species being delicious, mycorrhizal symbioses are of critical and increasingly appreciated importance to human society. This editorial provides an overview of the relevance and potential roles of mycorrhizal fungi toward achieving global goals in sustainability, conservation and their significance within society, and highlights key directions for future research

Effect of seeding date, environment, and storage on canola seed vigour

Non-Peer ReviewedSeed vigour has been identified as one of the leading factors limiting stand establishment and yield in western Canada. Field studies at Scott, SK demonstrated that seed derived from Fall and April-sown canola produced higher plant densities, higher biomass at bolting, and higher seed yield than seed derived from May-sown canola. This study established the impact of seeding date on seed quality and vigour, which in turn affected emergence, seedling vigour and yield. Also, seed vigour slowly declines within one year, primarily from seed derived from the May-sown canola. Currently we are in the process of uncovering which genes and proteins are in common with vigour irrespective of seed source. We will combine our analysis with synchrotron technologies for a much more in-depth understanding of what constitutes “seed vigour” to develop a rapid, simple, and inexpensive method that will identify intrinsic characteristics of superior seed lots, as well as seed lots that lose vigour when stored under adverse conditions. In addition, we have initiated a study to compare hormones and metabolites during cold acclimation and freeze-induced injury/recovery to correlate these changes with winter survival. This research will identify traits that can be used in marker-assisted/molecular breeding programs for winter hardiness and possible genetic engineering studies on abiotic stress tolerance of seeds and plants. To further understand the processes involved in stress tolerance, we utilized gene transfer techniques to produce a PNT canola that over-expresses a novel gene which results in higher yields under stressful conditions. These PNT lines were tested in the field over 3 years across Western Canada in non-stressed, moderately stressed, or severely stressed areas. At each location, several lines flowered and matured 1 to 3 weeks earlier. The faster maturating PNT lines (up to 55% more mature at harvest) had increased yields (up to 32% increase) and enhanced seed quality (up to 87% increase in larger and more mature seed) versus the control. These results, both in controlled laboratory tests and in field trials, have been optimistic for genetic engineering of plants for enhanced stress tolerance without losing agronomical important characteristics

Slicing Sets and Measures, and the Dimension of Exceptional Parameters

We consider the problem of slicing a compact metric space \Omega with sets of the form \pi_{\lambda}^{-1}\{t\}, where the mappings \pi_{\lambda} \colon \Omega \to \R, \lambda \in \R, are \emph{generalized projections}, introduced by Yuval Peres and Wilhelm Schlag in 2000. The basic question is: assuming that \Omega has Hausdorff dimension strictly greater than one, what is the dimension of the 'typical' slice \pi_{\lambda}^{-1}{t}, as the parameters \lambda and t vary. In the special case of the mappings \pi_{\lambda} being orthogonal projections restricted to a compact set \Omega \subset \R^{2}, the problem dates back to a 1954 paper by Marstrand: he proved that for almost every \lambda there exist positively many $t \in \R$ such that \dim \pi_{\lambda}^{-1}{t} = \dim \Omega - 1. For generalized projections, the same result was obtained 50 years later by J\"arvenp\"a\"a, J\"arvenp\"a\"a and Niemel\"a. In this paper, we improve the previously existing estimates by replacing the phrase 'almost all \lambda' with a sharp bound for the dimension of the exceptional parameters.Comment: 31 pages, three figures; several typos corrected and large parts of the third section rewritten in v3; to appear in J. Geom. Ana

Effects of Molybdenum Supplementation on Performance of Forage‐fed SteersReceiving High‐sulfur Water

There has been on‐going research in the area of the consumption of high‐sulfur (S) water by steers grazing rangeland as well as forage‐fed steers in a feedlot setting. During the summer of 2009, a trial was conducted on the effects of high‐S water in finishing steers supplemented with molybdenum (Mo). The main purpose of the research was to gather data that may aid in the formulation of a supplement to counteract the negative effects of high‐S water consumed by ruminant livestock species in areas where sulfur concentration in water sources is a risk to animal health and performance. The specific focus of this trial was to determine whether the feeding of supplemental Mo would improve animal health and performance by decreasing the formation of hydrogen sulfide gas (H2S) in the rumen. Yearling steers (n=96) were used for a 56‐d trial. The trial consisted of 3 treatment groups; a low‐S water group and two high‐S water groups. One high‐S water treatment group received the same pellet that the low‐S group was given and the other high‐S water treatment group received a pellet with supplemental Mo included. Rumen gas cap H2S was collected on d ‐1, 29 and 57. Weights were recorded on d ‐2, ‐1, 29, 56 and 57. There were no differences between treatments in water intake (P= 0.719), but feed intake was reduced in the steers receiving the supplemental Mo (P \u3c 0.001). There was a significant difference in ruminal H2S due to treatment (P= 0.014), with higher ruminal H2S in the steers receiving the supplemental Mo. Steers receiving the Mo supplement had lower ADG than steers in the other treatments (P= 0.009). Throughout the duration of the trial, two steers were removed from the trial due to advanced symptoms of sulfur‐induced PEM (sPEM) from the high‐S treatment with no supplemental M

Binary Collisions and the Slingshot Effect

We derive the equations for the gravity assist manoeuvre in the general 2D case without the constraints of circular planetary orbits or widely different masses as assumed by Broucke, and obtain the slingshot conditions and maximum energy gain for arbitrary mass ratios of two colliding rigid bodies. Using the geometric view developed in an earlier paper by the authors the possible trajectories are computed for both attractive or repulsive interactions yielding a further insight on the slingshot mechanics and its parametrization. The general slingshot manoeuvre for arbitrary masses is explained as a particular case of the possible outcomes of attractive or repulsive binary collisions, and the correlation between asymptotic information and orbital parameters is obtained in general.Comment: 12 pages, 7 figures, accepted for publication Dec'07, Celestial Mechanics and Dynamical Astronom

Variable Effects of Snow Conditions Across Boreal Mesocarnivore Species

Mesocarnivores are increasingly recognized as key drivers of community dynamics, but the effects of bottom-up and abiotic factors on mesocarnivore populations remain poorly understood. We evaluated the effects of snow conditions, prey abundance, and habitat type on the distribution of five sympatric mesocarnivore species in interior Alaska using repeated snow track surveys and occupancy modelling. Snow depth and snow compaction were the best predictors of mesocarnivore occupancy, with differential effects across species. Coyotes (Canis latrans (Say, 1823)) and red foxes (Vulpes vulpes L., 1758) occurred in areas of shallow, compact snow, Canada lynx (Lynx canadensis (Kerr, 1792)) occurred in areas of shallow, fluffy snow, and wolverines (Gulo gulo L., 1758) and marten (Martes americana (Turton, 1806)) occurred in areas of deep, fluffy snow. These findings indicate that altered snow conditions due to climate change may have strong direct effects on the distribution of northern mesocarnivores, with divergent effects across species

Mycorrhizal mediation of sustainable development goals

This special issue, brought together during a time of unprecedented global change, represents a unique collection of papers that shed light on the current and future significance of mycorrhiza-forming fungi in the human world. Across this selection of papers, we explore the significance and potential of mycorrhizal fungi to contribute towards our achievement of global change goals of improved sustainability, food security and conservation as well as how we might best implement mycorrhizal knowledge and technologies to achieve these outcomes in modern societies

Cold Nuclear Matter Effects on Dijet Productions in Relativistic Heavy-ion Reactions at LHC

We investigate the cold nuclear matter(CNM) effects on dijet productions in high-energy nuclear collisions at LHC with the next-to-leading order perturbative QCD. The nuclear modifications for dijet angular distributions, dijet invariant mass spectra, dijet transverse momentum spectra and dijet momentum imbalance due to CNM effects are calculated by incorporating EPS, EKS, HKN and DS param-etrization sets of parton distributions in nucleus . It is found that dijet angular distributions and dijet momentum imbalance are insensitive to the initial-state CNM effects and thus provide optimal tools to study the final-state hot QGP effects such as jet quenching. On the other hand, the invariant mass spectra and the transverse momentum spectra of dijet are generally enhanced in a wide region of the invariant mass or transverse momentum due to CNM effects with a feature opposite to the expected suppression because of the final-state parton energy loss effect in the QGP. The difference of EPS, EKS, HKN and DS parametrization sets of nuclear parton distribution functions is appreciable for dijet invariant mass spectra and transverse momentum spectra at p+Pb collisions, and becomes more pronounced for those at Pb+Pb reactions.Comment: 10 pages, 11 figure

Near-term deployment of carbon capture and sequestration from biorefineries in the United States

Capture and permanent geologic sequestration of biogenic CO2 emissions may provide critical flexibility in ambitious climate change mitigation. However, most bioenergy with carbon capture and sequestration (BECCS) technologies are technically immature or commercially unavailable. Here, we evaluate low-cost, commercially ready CO2 capture opportunities for existing ethanol biorefineries in the United States. The analysis combines process engineering, spatial optimization, and lifecycle assessment to consider the technical, economic, and institutional feasibility of near-term carbon capture and sequestration (CCS). Our modeling framework evaluates least cost source-sink relationships and aggregation opportunities for pipeline transport, which can cost-effectively transport small CO2 volumes to suitable sequestration sites; 216 existing US biorefineries emit 45 Mt CO2 annually from fermentation, of which 60% could be captured and compressed for pipeline transport for under $25/tCO2 A sequestration credit, analogous to existing CCS tax credits, of$60/tCO2 could incent 30 Mt of sequestration and 6,900 km of pipeline infrastructure across the United States. Similarly, a carbon abatement credit, analogous to existing tradeable CO2 credits, of $90/tCO2 can incent 38 Mt of abatement. Aggregation of CO2 sources enables cost-effective long-distance pipeline transport to distant sequestration sites. Financial incentives under the low-carbon fuel standard in California and recent revisions to existing federal tax credits suggest a substantial near-term opportunity to permanently sequester biogenic CO2 This financial opportunity could catalyze the growth of carbon capture, transport, and sequestration; improve the lifecycle impacts of conventional biofuels; support development of carbon-negative fuels; and help fulfill the mandates of low-carbon fuel policies across the United States