Science advice for global challenges: learning from trade-offs in the IPCC

In the context of ongoing debates about the place of knowledge and expertise in the governance of global challenges, this article seeks to promote cross-sectoral learning about the politics and pitfalls of global science advice. It begins with the intertwined histories of the Intergovernmental Panel on Climate Change (IPCC) and the global climate policy regime, before examining the politics of different ‘framings’ of the climate problem and the challenges of building and communicating scientific consensus. We then identify three important trade-offs which the IPCC has had to negotiate: global versus local; scientific disinterestedness versus policy-relevance; and consensus versus plurality. These lessons are especially timely as global institutions begin to convene knowledge to address urgent sustainable development challenges posed by anti-microbial resistance (AMR). While the IPCC experience does not provide a wholly transportable model for science advice, we show why similar trade-offs need to be addressed at an early stage by architects of advisory systems for AMR as well as other global challenges

DISSOLVED OXYGEN CHARACTERISTICS OF THE GAMTOOS ESTUARY, SOUTH AFRICA

The fall and recovery of dissolved oxygen (DO) is documented throughout the Gamtoos Estuary, South Africa during dry conditions and following light and heavy rainfall over a 13-month period from November 1992 to November 1993. Hypoxic conditions generally occurred in the near-bottom waters of the upper estuary. Localized fluctuations in DO levels are related to the natural diurnal fluctuation associated with photosynthesis of aquatic flora. The drop in DO levels following light rainfall is associated with the volume of oxygen-consuming compounds entering the estuary via runoff from adjacent agricultural fields. This hypoxia was short-lived. Following an extreme rainfall event, however, almost immediate hypoxia was recorded throughout the estuary, and DO levels deteriorated for some time thereafter as a result of the substantial input of organic matter into the estuary. The area of hypoxia and recovery was governed by the freshwater input at the tidal head, estuarine hydrometry and hydrodynamics. Tidal processes were identified as a source of replenishment of oxygen when, during high tide, seawater with a higher DO content penetrated the estuary.Afr. J. mar. Sci. 25: 99–10

Wind on the boundary for the Abelian sandpile model

We continue our investigation of the two-dimensional Abelian sandpile model in terms of a logarithmic conformal field theory with central charge c=-2, by introducing two new boundary conditions. These have two unusual features: they carry an intrinsic orientation, and, more strangely, they cannot be imposed uniformly on a whole boundary (like the edge of a cylinder). They lead to seven new boundary condition changing fields, some of them being in highest weight representations (weights -1/8, 0 and 3/8), some others belonging to indecomposable representations with rank 2 Jordan cells (lowest weights 0 and 1). Their fusion algebra appears to be in full agreement with the fusion rules conjectured by Gaberdiel and Kausch.Comment: 26 pages, 4 figure

Fusion algebra of critical percolation

We present an explicit conjecture for the chiral fusion algebra of critical percolation considering Virasoro representations with no enlarged or extended symmetry algebra. The representations we take to generate fusion are countably infinite in number. The ensuing fusion rules are quasi-rational in the sense that the fusion of a finite number of these representations decomposes into a finite direct sum of these representations. The fusion rules are commutative, associative and exhibit an sl(2) structure. They involve representations which we call Kac representations of which some are reducible yet indecomposable representations of rank 1. In particular, the identity of the fusion algebra is a reducible yet indecomposable Kac representation of rank 1. We make detailed comparisons of our fusion rules with the recent results of Eberle-Flohr and Read-Saleur. Notably, in agreement with Eberle-Flohr, we find the appearance of indecomposable representations of rank 3. Our fusion rules are supported by extensive numerical studies of an integrable lattice model of critical percolation. Details of our lattice findings and numerical results will be presented elsewhere.Comment: 12 pages, v2: comments and references adde

Development of laminar flow control wing surface porous structure

It was concluded that the chordwise air collection method, which actually combines chordwise and spanwise air collection, is the best of the designs conceived up to this time for full chord laminar flow control (LFC). Its shallower ducting improved structural efficiency of the main wing box resulting in a reduction in wing weight, and it provided continuous support of the chordwise panel joints, better matching of suction and clearing airflow requirements, and simplified duct to suction source minifolding. Laminar flow control on both the upper and lower surfaces was previously reduced to LFC suction on the upper surface only, back to 85 percent chord. The study concludes that, in addition to reduced wing area and other practical advantages, this system would be lighter because of the increase in effective structural wing thickness

Fundamental Limits of Classical and Quantum Imaging

Quantum imaging promises increased imaging performance over classical protocols. However, there are a number of aspects of quantum imaging that are not well understood. In particular, it has so far been unknown how to compare classical and quantum imaging procedures. Here, we consider classical and quantum imaging in a single theoretical framework and present general fundamental limits on the resolution and the deposition rate for classical and quantum imaging. The resolution can be estimated from the image itself. We present a utility function that allows us to compare imaging protocols in a wide range of applications.Comment: 4 pages, 3 figures; accepted for Physical Review Letters, with updated title and fixed typo

The phase of pre-stimulus alpha oscillations influences the visual perception of stimulus timing

AbstractThis study examined the influence of pre-stimulus alpha phase and attention on whether two visual stimuli occurring closely in time were perceived as simultaneous or asynchronous. The results demonstrated that certain phases of alpha in the period immediately preceding stimulus onset were associated with a higher proportion of stimuli judged to be asynchronous. Furthermore, this effect was shown to occur independently of both visuo-spatial attention and alpha amplitude. The findings are compatible with proposals that alpha phase reflects cyclic shifts in neuronal excitability. Importantly, however, the results further suggest that fluctuations in neuronal excitability can create a periodicity in neuronal transfer that can have functional consequences that are decoupled from changes in alpha amplitude. This study therefore provides evidence that perceptual processes fluctuate periodically although it remains uncertain whether this implies the discrete temporal framing of perception

Direct measurements of the polarization of terrestrial kilometric radiation from Voyagers 1 and 2

Terrestrial radiation measurements obtained with planetary radio astronomy experiments on Voyager-1 and 2 during the early portions of each flight show the signals to be predominantly left-hand circularly polarized. Since these emissions were most probably generated above the Northern Hemisphere auroral zone, it is concluded that the radiation is emitted primarily in the extraordinary mode

Toward Renewable Eenergy Geo-information Infrastructures: Applications of GIScience and Remote Sensing that Build Institutional Capacity

Sustained policy support is necessary in order to drive a transition toward renewable energy (RE). The ability to realize RE policy objectives is constrained by a range of geographic factors related to resource potential, the distribution of resources, land availability/suitability, the absorptive capacity of proximal infrastructure, and local socio-political acceptance. With this in mind, this paper provides a systematic review of how geographic information science and remote sensing techniques have been applied to reduce uncertainties surrounding renewable energy development, with emphasis on policy and planning needs. The concept of a ‘geo-information infrastructure’ is used to bring coherence and direction to this growing body of literature. The review highlights four underdeveloped research areas, including: Resolving issues of scalar discordance through comprehensive analysis at local and regional scales; mapping interactions in space of multiple supply options to deliver more accurate and sophisticated estimates of RE potential in an area and to identify competitive and symbiotic land-use situations; using energy resource maps as primary inputs into the development of technology road-maps; and developing geographically explicit indicators which can signal priority areas for RE recovery based on social and environmental returns on investments. In each case, suggestions moving forward are provided. The paper identifies knowledge-based institutional networking as a pathway through which local and regional public authorities can be equipped with the resources necessary to build and mobilize a geo-information infrastructure

Improved Parametric Empirical Determination of Module Short Circuit Current for Modelling and Optimization of Solar Photovoltaic Systems

Correct modelling of solar photovoltaic (PV) system yields is necessary to optimize system design, improve reliability of projected outputs to ensure favourable project financing and to facilitate proper operations and maintenance. An improved methodology for fine resolution modelling of PV systems is presented using module short-circuit current (Isc) at 5-minute time-scales, and clearly identifies pertinent error mechanisms that arise when working at this high resolution. This work used a modified version of the Sandia array performance model, and introduces new factors to the calculation of Isc to account for identified error mechanisms, including instrumentation alignment, spectral, and module power tolerance errors. A simple methodology was introduced and verified where specific module parameters can be derived solely from properly filtered performance time series data. In particular, this paper focused on methodologies for determining the predicted Isc for a variety of solar PV module types. These methods of regressive analysis significantly reduced the error of the predicted model, and demonstrate the need for this form of modelling when evaluating long term PV array performance. This methodology has applications for current systems operators, which will enable the extraction of useful module parameters from existing data in addition to more precise continuous monitoring of existing systems, and can also be used to more accurately model and optimize new systems