Stabilization and plant uptake of N from 15N-labelled pea residue 16.5 years after incorporation in soil

The decline of N from 15N-labelled mature pea residues was followed in unplanted soil over 16.5 yr. Eight years after residue incorporation, 24% of the residue 15N input was still present in the soil and, after 16.5 yr, 16% of the residue 15N input remained. A double exponential model successfully described the decay of N from 15N-labelled pea residues. The total residual 15N declined with average decay constants of 1.45 yr−1 for the 30 d to 1 yr period and of 0.07 yr−1 for the 1–16 yr period. Sixteen years following incorporation of the residues, indicator plants growing in residues-amended soils were obtaining 1.7% of their N from residue N. This is, to our knowledge, the longest study on decay of N in soils from 15N-labelled crop residues. The current study thus provides a unique data set for our empirical understanding of N-dynamics in agricultural systems, which is a prerequisite to parameterize and validate N-simulation models

Developing Energy Plants for Biofuels Production may Comply to Organic Principles

Biofuels are the only source of renewable environmentally friendly fuel currently suitable for road transport without any negative traits associated with traditional biodiesel or other green energy alternatives. The combustion of petrol and diesel produces many different types of local air pollutants, but the use of biofuels may result in the reductions in emissions of greenhouse gas carbon dioxide up to 70%. Impacts on land use require careful planning to maximise the gains and minimise the losses. The role of biofuels in organic farming will solve three significant problems: 1) waste will become valuable resources; 2) low quality forage products can be utilized for biofuels and thus get value-added; and 3) the trafficable damage on soil fertilities will be reduced by the minimized recirculation rate of bulky watery waste products

Critical behavior of an absorbing phase transition in an interacting monomer-dimer model

We study a monomer-dimer model with repulsive interactions between the same species in one dimension. With infinitely strong interactions the model exhibits a continuous transition from a reactive phase to an inactive phase with two equivalent absorbing states. Static and dynamic Monte Carlo simulations show that the critical behavior at the transition is different from the conventional directed percolation universality class but is consistent with that of the models with the mass conservation of modulo 2. The values of static and dynamic critical exponents are compared with those of other models. We also show that the directed percolation universality class is recovered when a symmetry-breaking field is introduced.Comment: 9 pages, latex, 1 figure (one PS figure file upon request) (appear in Physica A (1995): Proceeding of Statphys-Taipei-1995

Generalized Nonlinear Complementary Attitude Filter

This work describes a family of attitude estimators that are based on a generalization of Mahony's nonlinear complementary filter. This generalization reveals the close mathematical relationship between the nonlinear complementary filter and the more traditional multiplicative extended Kalman filter. In fact, the bias-free and constant gain multiplicative continuous-time extended Kalman filters may be interpreted as special cases of the generalized attitude estimator. The correspondence provides a rational means of choosing the gains for the nonlinear complementary filter and a proof of the near global asymptotic stability of special cases of the multiplicative extended Kalman filter

Is ʔ an Element? Towards a Non-segmental Phonology

This paper argues that the element calculus of Government Phonology is overburdened. In particular it shows that the simple act of supposing extra elements to explain consonantal phenomena leads to far reaching and undesirable empirical consequences. An alternative approach is proposed which leaves the elemental inventory containing only those elements attested in both nuclei and non-nuclei. The phonetic impression of consonantism is attributed to the direct interpretation of supra-skeletal structure. Some typical textbook problems involving consonant ‘mutations’ are explored in light of this simple shift of perspective, with attractive solutions. The metatheoretical benefits of this approach are highlighted and particular areas of existing supra-skeletal theory are singled out as likely to require ‘tweaking’

Managing Library Electronic Resources Using Google Sites

After attempting to use a home-grown Drupal database to administer electronic resources and later a vendor-provided electronic resources management (ERM) system, the University of Alaska Fairbanks Libraries created a Google Site that quickly proved to be more efficient than either previous system. Although this new system may not be a permanent solution, as ERM software continues to evolve, this original answer to a complex problem streamlines workflow, allows for further innovation and development and, best of all, comes with a Google mail account, and no formal training is needed

A master bosonization duality

We conjecture a new sequence of dualities between Chern-Simons gauge theories simultaneously coupled to fundamental bosons and fermions. These dualities reduce to those proposed by Aharony when the number of bosons or fermions is zero. Our conjecture passes a number of consistency checks. These include the matching of global symmetries and consistency with level/rank duality in massive phases.Comment: 29 pages, 2 figures; v2: minor improvements; v3: typos fixe

No More Liaisons: Collection Management Strategies in Hard Times

Collection development in medium to large academic libraries typically involves multiple subject librarians or “liaisons.” The University of Alaska Fairbanks (UAF) Libraries have lost significant numbers of personnel in the last four years due to attrition and retirements, including most of the professional liaison librarians whose positions will not be replaced in the foreseeable future. In addition to this challenge, collection budgets have been severely reduced due to the State of Alaska's ongoing budget crisis, necessitating large cancellation projects. This article examines UAF Libraries’ collection strategies used to sustain a research-intensive collection without liaisons and with a drastically reduced budget