Updating "small world representations" in strategic decision-making under extreme uncertainty

The behavioral strategy literature investigates how decision makers might use Small World Representations (SWRs) to guide their actions in situations of extreme uncertainty, but says little about how such representations should be updated during the implementation phase. In this paper, we provide a framework to capture the relationship between SWRs, unknowns and Black Swans, and, drawing on the psychology of reasoning literature, explore different heuristic methods of inquiry that decision makers might use to update their SWRs. We compare the performance of two such methods⎯disconfirmation and counterfactual reasoning⎯in highly uncertain situations characterized by ambiguous and non-definite information. We find that counterfactual reasoning is superior to disconfirmation with respect to (1) counteracting the confirmation bias, (2) promoting the exploration of the scenario space, and (3) favoring the adoption of actions able to mitigate or exploit the consequences of Black Swans

Dirac R-matrix calculations for the electron-impact excitation of neutral tungsten providing noninvasive diagnostics for magnetic confinement fusion

Neutral tungsten is the primary candidate as a wall material in the divertor region of the International Thermonuclear Experimental Reactor (ITER). The efficient operation of ITER depends heavily on precise atomic physics calculations for the determination of reliable erosion diagnostics, helping to characterise the influx of tungsten impurities into the core plasma. The following paper presents detailed calculations of the atomic structure of neutral tungsten using the multiconfigurational Dirac-Fock method, drawing comparisons with experimental measurements where available, and includes a critical assessment of existing atomic structure data. We investigate the electron-impact excitation of neutral tungsten using the Dirac R-matrix method and, by employing collisional-radiative models, we benchmark our results with recent Compact Toroidal Hybrid measurements. The resulting comparisons highlight alternative diagnostic lines to the widely used 400.88nm line.Comment: 10 pages, 6 figure

Economic Value of Recreational Use of South Australia’s National Parks and Reserves: Kangaroo Island Wilderness Trail Case Study

Eco­nom­ic val­ue of SA’s Parks – Tech­ni­cal report 3 (Kan­ga­roo Island Wilderness Trail Case Study)By: A/Prof Adam Loch, Christopher Auricht and A/Prof Patrick O’Conno

The Golden Gift of Groundwater in Australia’s MDB

The Murray-Darling Basin (MDB) has the second-most variable surface flows in the world. The unreliable nature of MDB surface water supply is expected to increase under climate change. To partially address this future problem, Australia’s government released 927 gigalitres (GL = 1 billion litres) of groundwater rights to agricultural users in the basin under the Murray-Darling Basin Plan (2012-2026). A key argument for that action was the perception that groundwater resources in the basin are sustainable, and more reliable, than surface water resources. Access to more reliable water often transforms agricultural cropping choices. This chapter uses an optimization model of the MDB to explore how basin agriculture may transform in response to reliable water access—particularly in the northern part of the MDB. We find that traditional opportunistic cropping systems (i.e., annuals) shift towards high-value systems (e.g., perennials) and change irrigation practices when access to groundwater resources is increased. We also examine the change in value for those new groundwater rights as climate change impacts take hold.David Adamson, Christopher Auricht and Adam Loc

Value of South Australia’s National Parks and Reserves. Study 1: Economic value of nature-based tourism. Part 2. Secondary economic value

Eco­nom­ic val­ue of SA’s Parks – Tech­ni­cal report 2 (Sec­ondary eco­nom­ic value)By: A/Prof Adam Loch, Christopher Auricht and A/Prof Patrick O’Conno

Lower entropy bounds and particle number fluctuations in a Fermi sea

We demonstrate, in an elementary manner, that given a partition of the single particle Hilbert space into orthogonal subspaces, a Fermi sea may be factored into pairs of entangled modes, similar to a BCS state. We derive expressions for the entropy and for the particle number fluctuations of a subspace of a fermi sea, at zero and finite temperatures, and relate these by a lower bound on the entropy. As an application we investigate analytically and numerically these quantities for electrons in the lowest Landau level of a quantum Hall sample.Comment: shorter version, typos fixe

TESTING PROCEDURES TO CHARACTERISE TUNNELLING RISK ON SPOIL MATERIALS

Abstract Many factors affect the success or failure of attempts to stabilise and rehabilitate waste rock dumps on mines. Major erosion causing waste rock dump "failure" is often associated with unstable materials prone to tunnelling, including dispersive spoils. The presence of these materials commonly results in the failure of berms at points where tunnels develop, creation of relatively unsafe landforms with widespread tunnels immediately below the soil surface, development of large gullies when tunnels collapse, and instability of rock drains. Although tunnel erosion is commonly considered to be associated with dispersion, some non-dispersive mine spoil materials have been shown to be highly susceptible to tunnelling. Similarly, materials that are initially stable often undergo chemical and physical changes over time that lead to subsequent tunnel formation. Hence, there is a need for the development of more comprehensive testing procedures to identify materials at risk of tunnel erosion. This paper reports on the development of a laboratory based testing procedure to characterise the risk of tunnelling failure on the basis of soil properties and failure mechanisms. The test procedure also provides information on the impact of leaching on the potential for tunnel formation over time

A large-scale R-matrix calculation for electron-impact excitation of the Ne2+^{2+} O-like ion

The five J$\Pi$ levels within a $np^2$ or $np^4$ ground state complex provide an excellent testing ground for the comparison of theoretical line ratios with astrophysically observed values, in addition to providing valuable electron temperature and density diagnostics. The low temperature nature of the line ratios ensure that the theoretically derived values are sensitive to the underlying atomic structure and electron-impact excitation rates. Previous R-matrix calculations for the Ne$^{2+}$ O-like ion exhibit large spurious structure in the cross sections at higher electron energies, which may affect Maxwellian averaged rates even at low temperatures. Furthermore, there is an absence of comprehensive excitation data between the excited states that may provide newer diagnostics to compliment the more established lines discussed in this paper. To resolve these issues, we present both a small scale 56-level Breit-Pauli (BP) calculation and a large-scale 554 levels R-matrix Intermediate Coupling Frame Transformation (ICFT) calculation that extends the scope and validity of earlier JAJOM calculations both in terms of the atomic structure and scattering cross sections. Our results provide a comprehensive electron-impact excitation data set for all transitions to higher $n$ shells. The fundamental atomic data for this O-like ion is subsequently used within a collisional radiative framework to provide the line ratios across a range of electron temperatures and densities of interest in astrophysical observations.Comment: 17 pages, 8 figure

Varicellovirus UL 49.5 proteins differentially affect the function of the transporter associated with antigen processing, TAP

Cytotoxic T-lymphocytes play an important role in the protection against viral infections, which they detect through the recognition of virus-derived peptides, presented in the context of MHC class I molecules at the surface of the infected cell. The transporter associated with antigen processing (TAP) plays an essential role in MHC class I–restricted antigen presentation, as TAP imports peptides into the ER, where peptide loading of MHC class I molecules takes place. In this study, the UL49.5 proteins of the varicelloviruses bovine herpesvirus 1 (BHV-1), pseudorabies virus (PRV), and equine herpesvirus 1 and 4 (EHV-1 and EHV-4) are characterized as members of a novel class of viral immune evasion proteins. These UL49.5 proteins interfere with MHC class I antigen presentation by blocking the supply of antigenic peptides through inhibition of TAP. BHV-1, PRV, and EHV-1 recombinant viruses lacking UL49.5 no longer interfere with peptide transport. Combined with the observation that the individually expressed UL49.5 proteins block TAP as well, these data indicate that UL49.5 is the viral factor that is both necessary and sufficient to abolish TAP function during productive infection by these viruses. The mechanisms through which the UL49.5 proteins of BHV-1, PRV, EHV-1, and EHV-4 block TAP exhibit surprising diversity. BHV-1 UL49.5 targets TAP for proteasomal degradation, whereas EHV-1 and EHV-4 UL49.5 interfere with the binding of ATP to TAP. In contrast, TAP stability and ATP recruitment are not affected by PRV UL49.5, although it has the capacity to arrest the peptide transporter in a translocation-incompetent state, a property shared with the BHV-1 and EHV-1 UL49.5. Taken together, these results classify the UL49.5 gene products of BHV-1, PRV, EHV-1, and EHV-4 as members of a novel family of viral immune evasion proteins, inhibiting TAP through a variety of mechanisms

Heuristic methods for updating small world representations in strategic situations of Knightian uncertainty

Recent studies on the construction and use of “small world representations” in strategic decision-making under Knightian uncertainty say little about how such representations should be updated over the implementation phase. This paper draws on the psychology of reasoning to take a step towards answering this question. We begin by theorizing small world representations and how the scenario spaces they contain are constructed and may be updated over time. We then introduce two well-known heuristic methods of inquiry, disconfirmation and counterfactual reasoning, translate them into practical procedures for updating scenario spaces, and compare the relative performance of these procedures in strategic situations of Knightian uncertainty. Our principal findings are that the procedure based on counterfactual reasoning is superior to the one based on disconfirmation with respect to (1) counteracting the confirmation bias, (2) promoting the exploration of the set of imaginable scenarios, and (3) facilitating action to mitigate or exploit the consequences of what would otherwise have been Black Swans. We close with some broader implications for the study of strategic decision-making under Knightian uncertainty