A Benchmark for Semi-Inductive Link Prediction in Knowledge Graphs

Semi-inductive link prediction (LP) in knowledge graphs (KG) is the task of predicting facts for new, previously unseen entities based on context information. Although new entities can be integrated by retraining the model from scratch in principle, such an approach is infeasible for large-scale KGs, where retraining is expensive and new entities may arise frequently. In this paper, we propose and describe a large-scale benchmark to evaluate semi-inductive LP models. The benchmark is based on and extends Wikidata5M: It provides transductive, k-shot, and 0-shot LP tasks, each varying the available information from (i) only KG structure, to (ii) including textual mentions, and (iii) detailed descriptions of the entities. We report on a small study of recent approaches and found that semi-inductive LP performance is far from transductive performance on long-tail entities throughout all experiments. The benchmark provides a test bed for further research into integrating context and textual information in semi-inductive LP models

Effects of Nitrogen Availability on the Fate of Litter-Carbon and Soil Organic Matter Decomposition

Aims: To determine whether addition of inorganic nitrogen (N) directly to maize litter (stalk and leaf) with differing tissue quality impacts litter and soil organic matter (SOM) decomposition. We tested whether N addition leads to 1) faster litter decomposition, 2) less SOM-C decomposition and 3) increased incorporation of organic-C into soil-C fractions thereby increasing C sequestration potential in maize-based systems. Methodology: We investigated decomposition of two types of maize litter (stalk and leaf) with differing tissue quality both in the field and in a laboratory incubation experiment. In the field, litter was placed on the soil surface and at 10 cm soil depth to investigate the effect of litter burial and N addition on litter decomposition. Litter was harvested at six and twelve month intervals. In the incubation experiment, maize and stalk litter was ground and incorporated into the soil and incubated at 25ºC for 120 days. We measured CO2-C evolved and employed δ13C natural abundance differences between litter-C and SOM-C to measure both litter-C and SOM-C decomposition. At the end of the experiment, we examined soil-C storage via soil physical fractionation. Results: Exogenous N addition to litter had little effect both litter and SOM decomposition in the field and the laboratory except for in the stalk litter treatment where there was an 8% decrease in litter-C loss and a 5% increase in SOM-C loss in the laboratory incubation experiment. N addition to litter increased decomposition of litter in the first 20 days of litter decomposition in the laboratory incubation experiment, but reduced litter decomposition rates after day 20. N addition to litter had very little effect on C storage in soil aggregates. In the field, litter placement, and physical litter structure influenced decomposition much more than N inputs. Thus, adding N to litter is not an effective strategy to sequester C in maize-based systems

Ecophysiolgoical Responses of \u3ci\u3eSchizachyrium scoparium\u3c/i\u3e to Water and Nitrogen Manipulations

Nitrogen is increasing in terrestrial ecosystems as a result of agricultural practices and the burning of fossil fuels. This increase is expected to be accompanied by changes in water availability due to global warming. We examined the effects of nitrogen and water manipulations on Schizachyrium scoparium, one of the dominant grasses in the Great Plains. Schizachyrium scoparium responded positively to watering, with an increase in photosynthesis, stomatal conductance, water and nitrogen use efficiencies, and water potential. Under watered conditions, fertilization had no significant effect on measured parameters, except for nitrogen-use efficiency. Significant differences appeared between fertilized and nonfertilized plants under moderate drought, with fertilized plants maintaining higher photosynthesis and water-use efficiency than nonfertilized plants. Water potential declined with water stress but did not differ between fertilization treatments, while nitrogen-use efficiency was significantly higher under non fertilized than fertilized treatment. Differences among fertilization treatments disappeared under severe drought. We conclude that S. scoparium will likely respond positively to fertilization under moderate drought in the Great Plains. However, under severe drought, fertilization will not provide any physiological advantages to S. scoparium

Empirical insights into the benefit from implementing smart contracts

Smart contracts are highly relevant due to their support for new decentralized business models and processes. We empirically investigate the benefit of implementing smart contracts. Our approach measures the benefit by capturing the impact of implementing smart contracts on processes directly. Thus, our research supersedes previous research that uses deductive approaches for deriving beneficial effects from technical and architectural properties of smart contracts and blockchains. We conduct a systematic approach using the aspects cost, quality, time and flexibility, and their impact on the four process phases interest, agreement, fulfillment, and assessment. Our research enables decision-makers to make decisions on implementing smart contracts more precisely. Furthermore, decision-makers become able to develop more target-oriented initiatives

Nitrogen uptake strategies of edaphically specialized Bornean tree species

The association of tree species with particular soil types contributes to high b diversity in forests, but the mechanisms producing such distributions are still debated. Soil nitrogen (N) often limits growth and occurs in differentially available chemical forms. In a Bornean forest where tree species composition changes dramatically along a soil gradient varying in supplies of different N-forms, we investigated whether tree species’ N-uptake and soil specialization strategies covaried. We analyzed foliar 15N natural abundance for a total of 216 tree species on clay or sandy loam (the soils at the gradient’s extremes) and conducted a 15N-tracer experiment with nine specialist and generalist species to test whether species displayed flexible or differential uptake of ammonium and nitrate. Despite variation in ammonium and nitrate supplies and nearly 4 % difference in foliar δ15N between most soil specialists and populations of generalists on these soils, our 15N tracer experiment showed little support for the hypothesis that soil specialists vary in N-form use or the ratios in which they use these forms. Instead, our results indicate that these species possess flexible capacities to take up different inorganic N forms. Variation between soil specialists in uptake of different N forms is thus unlikely to cause the soil associations of tree species and high b diversity characteristic of this Bornean rain forest. Flexible uptake strategies would facilitate N-acquisition when supply rates of N-forms exhibit spatiotemporal variation and suggest that these species may be functionally redundant in their responses to N gradients and influences on ecosystem N-cycles

Accelerating the approach of dissipative quantum spin systems towards stationarity through global spin rotations

We consider open quantum systems whose dynamics is governed by a time-independent Markovian Lindblad master equation. Such systems approach their stationary state on a timescale that is determined by the spectral gap of the generator of the master equation dynamics. In a recent paper [Carollo, Phys. Rev. Lett. 127, 060401 (2021)PRLTAO0031-900710.1103/PhysRevLett.127.060401] it was shown that under certain circumstances it was possible to exponentially accelerate the approach to stationarity by performing a unitary transformation of the initial state. This phenomenon can be regarded as the quantum version of the so-called Mpemba effect. The transformation of the initial state removes its overlap with the dynamical mode of the open system dynamics that possesses the slowest decay rate and, thus, determines the spectral gap. Whereas this transformation can be exactly constructed in some cases, it is, in practice, challenging to implement. Here we show that even far simpler transformations constructed by a global unitary spin rotation allow to exponentially speed up relaxation. We demonstrate this using simple dissipative quantum spin systems, which are relevant for current quantum simulation and computation platforms based on trapped atoms and ions