A warming climate will make Australian soil a net emitter of atmospheric CO2

Understanding the change in soil organic carbon (C) stock in a warmer climate and the effect of current land management on that stock is critical for soil and environmental conservation and climate policy. By simulation modeling, we predicted changes in Australia’s soil organic C stock from 2010 to 2100. These vary from losses of 0.014–0.077 t C ha−1 year−1 between 2020 and 2045 and 0.013–0.047 t C ha−1 year−1 between 2070 and 2100, under increasing emissions of greenhouse gases and temperature. Thus, Australian soil will be a net emitter of CO2. Depending on the future socio-economic conditions, we predict that croplands will accrue as much as 0.19 t C ha−1 year−1 between 2020 and 2045 due to their management, but accrual will decrease with warming and increased emissions by 2070–2100. The gains will be too small to counteract the losses of C from the larger areas of rangelands and coastal regions that are more sensitive to a warmer climate. In principle, prudent management of the rangelands, for example, improving grazing management and regenerating biodiverse, endemic native plant communities, could sequester more C and mitigate the loss; in practice, it may be more difficult, requiring innovation, interdisciplinary science, cultural awareness and effective policie

Transferring structural knowledge across cognitive maps in humans and models

Relations between task elements often follow hidden underlying structural forms such as periodicities or hierarchies, whose inferences fosters performance. However, transferring structural knowledge to novel environments requires flexible representations that are generalizable over particularities of the current environment, such as its stimuli and size. We suggest that humans represent structural forms as abstract basis sets and that in novel tasks, the structural form is inferred and the relevant basis set is transferred. Using a computational model, we show that such representation allows inference of the underlying structural form, important task states, effective behavioural policies and the existence of unobserved state-trajectories. In two experiments, participants learned three abstract graphs during two successive days. We tested how structural knowledge acquired on Day-1 affected Day-2 performance. In line with our model, participants who had a correct structural prior were able to infer the existence of unobserved state-trajectories and appropriate behavioural policies

Intense, carrier frequency and bandwidth tunable quasi single-cycle pulses from an organic emitter covering the Terahertz frequency gap

In Terahertz (THz) science, one of the long-standing challenges has been the formation of spectrally dense, single-cycle pulses with tunable duration and spectrum across the frequency range of 0.1-15 THz (THz gap). This frequency band, lying between the electronically and optically accessible spectra hosts important molecular fingerprints and collective modes which cannot be fully controlled by present strong-field THz sources. We present a method that provides powerful single-cycle THz pulses in the THz gap with a stable absolute phase whose duration can be continuously selected between 68 fs and 1100 fs. The loss-free and chirp-free technique is based on optical rectification of a wavelength-tunable pump pulse in the organic emitter HMQ-TMS that allows for tuning of the spectral bandwidth from 1 to more than 7 octaves over the entire THz gap. The presented source tunability of the temporal carrier frequency and spectrum expands the scope of spectrally dense THz sources to time-resolved nonlinear THz spectroscopy in the entire THz gap. This opens new opportunities towards ultrafast coherent control over matter and light

Potential of a Neutrino Detector in the ANDES Underground Laboratory for Geophysics and Astrophysics of Neutrinos

The construction of the Agua Negra tunnels that will link Argentina and Chile under the Andes, the world longest mountain range, opens the possibility to build the first deep underground labo- ratory in the Southern Hemisphere. This laboratory has the acronym ANDES (Agua Negra Deep Experiment Site) and its overburden could be as large as \sim 1.7 km of rock, or 4500 mwe, providing an excellent low background environment to study physics of rare events like the ones induced by neutrinos and/or dark matter. In this paper we investigate the physics potential of a few kiloton size liquid scintillator detector, which could be constructed in the ANDES laboratory as one of its possible scientific programs. In particular, we evaluate the impact of such a detector for the studies of geoneutrinos and galactic supernova neutrinos assuming a fiducial volume of 3 kilotons as a reference size. We emphasize the complementary roles of such a detector to the ones in the Northern Hemisphere neutrino facilities through some advantages due to its geographical location.Comment: 20 pages, 16 figures and 9 table

Spatially uniform calibration of a liquid xenon detector at low energies using 83m-Kr

A difficult task with many particle detectors focusing on interactions below ~100 keV is to perform a calibration in the appropriate energy range that adequately probes all regions of the detector. Because detector response can vary greatly in various locations within the device, a spatially uniform calibration is important. We present a new method for calibration of liquid xenon (LXe) detectors, using the short-lived 83m-Kr. This source has transitions at 9.4 and 32.1 keV, and as a noble gas like Xe, it disperses uniformly in all regions of the detector. Even for low source activities, the existence of the two transitions provides a method of identifying the decays that is free of background. We find that at decreasing energies, the LXe light yield increases, while the amount of electric field quenching is diminished. Additionally, we show that if any long-lived radioactive backgrounds are introduced by this method, they will present less than 67E-6 events/kg/day in the next generation of LXe dark matter direct detection searchesComment: 9 pages, 9 figures. Accepted to Review of Scientific Instrument

Neural signatures of strategic types in a two-person bargaining game

The management and manipulation of our own social image in the minds of others requires difficult and poorly understood computations. One computation useful in social image management is strategic deception: our ability and willingness to manipulate other people's beliefs about ourselves for gain. We used an interpersonal bargaining game to probe the capacity of players to manage their partner's beliefs about them. This probe parsed the group of subjects into three behavioral types according to their revealed level of strategic deception; these types were also distinguished by neural data measured during the game. The most deceptive subjects emitted behavioral signals that mimicked a more benign behavioral type, and their brains showed differential activation in right dorsolateral prefrontal cortex and left Brodmann area 10 at the time of this deception. In addition, strategic types showed a significant correlation between activation in the right temporoparietal junction and expected payoff that was absent in the other groups. The neurobehavioral types identified by the game raise the possibility of identifying quantitative biomarkers for the capacity to manipulate and maintain a social image in another person's mind

First Steps into Practical Engineering for Freshman Students Using MATLAB and LEGO Mindstorms Robots

Besides lectures on basic theoretical topics, contemporary teaching and learning concepts for first semester students give more and more consideration to practically motivated courses. In this context, a new first-year introductory course in practical engineering has been established in the first semester curriculum of Electrical Engineering at RWTH Aachen University, Germany. Based on a threefold learning concept, programming skills in MATLAB are taught to 309 students within a full-time block course laboratory. The students are encouraged to transfer known mathematical basics to program algorithms and real-world applications performed by 100 LEGO Mindstorms robots. A new MATLAB toolbox and twofold project tasks have been developed for this purpose by a small team of supervisors. The students are supervised by over 60 tutors at 23 institutes, and are encouraged to create their own robotics applications. We describe how the laboratory motivates the students to act and think like engineers and to solve real-world issues with limited resources. The evaluation results show that the proposed practical course concept successfully boosts students’ motivation, advances their programming skills, and encourages the peer learning process.

Arthropods as vectors of esca-related pathogens: Transmission efficiency of ants and earwigs and the potential of earwig feces as inoculum source in vineyards

The spread of Grapevine trunk diseases (GTDs) such as esca concerns wine growers worldwide. Besides rain-splash and air currents, arthropods may play an additional role in the dissemination of esca-related pathogens such as Phaeomoniella chlamydospora (Pch) and Phaeoacremonium minimum (Pmm). The present study confirms that black garden ants (Lasius niger L., Formicidae: Formicinae) and European earwigs (Forficula auricularia L., Dermaptera: Forficulidae) can, under artificial conditions, efficiently transmit spores of Pch and Pmm to healthy grapevine cuttings, causing new infections. The potential of earwig feces as inoculum source in vineyards is additionally discussed. Spores of Pch and Pmm retained germination ability after earwig gut passage, and infectious feces successfully infected wounded grapevine cuttings under artificial conditions. However, molecular detection frequencies of esca-related pathogens in earwig feces collected from the field were very low. With this, the risk of earwig feces as inoculum source for esca-related pathogens is probably only marginal. However, arthropods carrying esca-related spores on their exoskeletons, such as ants and earwigs, might contribute to the overall spread of esca in vineyards. The invasion of GTDs during the phase of pruning wound susceptibility, either by arthropod vectors or by airborne spores, can efficiently be prevented by adequate pruning wound protection

Possible large direct CP asymmetry in hadronic B+- -> \pi+- \eta' decays

We calculate the branching ratio and direct CP asymmetry in nonleptonic two body B decays B^+- ->\pi^+- \eta'. It is shown that the tree diagram and gluon fusion mechanism via penguin diagram have comparable contributions to these decays which, as a result, could provide an interesting venue for investigating CP violation. Our estimate shows that the direct CP asymmetry in the above decays could be as large as 75% which along with a branching ratio B(B^- ->\pi^- \eta')=3.4 X 10^{-6} should be accessible to experiment in the near future.Comment: 13 pages, Revtex, 4 figures (included