The biggest mistakes governments made during COVID– and what the future could hold

Christopher Murray (University of Washington) looks at the mistakes made during the pandemic and how its ramifications will play out in the coming years

Forecasting the response of Earth\u27s surface to future climatic and land use changes: A review of methods and research needs

In the future, Earth will be warmer, precipitation events will be more extreme, global mean sea level will rise, and many arid and semiarid regions will be drier. Human modifications of landscapes will also occur at an accelerated rate as developed areas increase in size and population density. We now have gridded global forecasts, being continually improved, of the climatic and land use changes (C&LUC) that are likely to occur in the coming decades. However, besides a few exceptions, consensus forecasts do not exist for how these C&LUC will likely impact Earth-surface processes and hazards. In some cases, we have the tools to forecast the geomorphic responses to likely future C&LUC. Fully exploiting these models and utilizing these tools will require close collaboration among Earth-surface scientists and Earth-system modelers. This paper assesses the state-of-the-art tools and data that are being used or could be used to forecast changes in the state of Earth\u27s surface as a result of likely future C&LUC. We also propose strategies for filling key knowledge gaps, emphasizing where additional basic research and/or collaboration across disciplines are necessary. The main body of the paper addresses cross-cutting issues, including the importance of nonlinear/threshold-dominated interactions among topography, vegetation, and sediment transport, as well as the importance of alternate stable states and extreme, rare events for understanding and forecasting Earth-surface response to C&LUC. Five supplements delve into different scales or process zones (global-scale assessments and fluvial, aeolian, glacial/periglacial, and coastal process zones) in detail. © 2015 The Authors. Earth\u27s Future published by Wiley on behalf of the American Geophysical Union

Outflows at the Edges of an Active Region in a Coronal Hole: A Signature of Active Region Expansion?

Outflows of plasma at the edges of active regions surrounded by quiet Sun are now a common observation with the Hinode satellite. While there is observational evidence to suggest that the outflows are originating in the magnetic field surrounding the active regions, there is no conclusive evidence that reveals how they are driven. Motivated by observations of outflows at the periphery of a mature active region embedded in a coronal hole, we have used a three-dimensional simulation to emulate the active region's development in order to investigate the origin and driver of these outflows. We find outflows are accelerated from a site in the coronal hole magnetic field immediately surrounding the active region and are channelled along the coronal hole field as they rise through the atmosphere. The plasma is accelerated simply as a result of the active region expanding horizontally as it develops. Many of the characteristics of the outflows generated in the simulation are consistent with those of observed outflows: velocities up to 45 km per sec, properties akin to the coronal hole, proximity to the active region's draining loops, expansion with height, and projection over monopolar photospheric magnetic concentrations. Although the horizontal expansion occurs as a consequence of the active region's development in the simulation, expansion is also a general feature of established active regions. Hence, it is entirely possible and plausible that the expansion acceleration mechanism displayed in the simulation is occurring in active regions on the Sun and, in addition to reconnection, is driving the outflows observed at their edges.Comment: 19 pages, 9 figure

‘Because it’s our culture!’ (Re)negotiating the meaning of lobola in Southern African secondary schools

Payment of bridewealth or lobola is a significant element of marriage among the Basotho of Lesotho and the Shona of Zimbabwe. However, the functions and meanings attached to the practice are constantly changing. In order to gauge the interpretations attached to lobola by young people today, this paper analyses a series of focus group discussions conducted among senior students at two rural secondary schools. It compares the interpretations attached by the students to the practice of lobola with academic interpretations (both historical and contemporary). Among young people the meanings and functions of lobola are hotly contested, but differ markedly from those set out in the academic literature. While many students see lobola as a valued part of ‘African culture’, most also view it as a financial transaction which necessarily disadvantages women. The paper then seeks to explain the young people’s interpretations by reference to discourses of ‘equal rights’ and ‘culture’ prevalent in secondary schools. Young people make use of these discourses in (re)negotiating the meaning of lobola, but the limitations of the discourses restrict the interpretations of lobola available to them

Phenomenological constraints on Lemaitre-Tolman-Bondi cosmological inhomogeneities from solar system dynamics

We, first, analytically work out the long-term, i.e. averaged over one orbital revolution, perturbations on the orbit of a test particle moving in a local Fermi frame induced therein by the cosmological tidal effects of the inhomogeneous Lemaitre-Tolman-Bondi (LTB) model. The LTB solution has recently attracted attention, among other things, as a possible explanation of the observed cosmic acceleration without resorting to dark energy. Then, we phenomenologically constrain both the parameters K_1 = -\ddot R/R and K_2 = -\ddot R^'/R^' of the LTB metric in the Fermi frame by using different kinds of solar system data. The corrections $\Delta\dot\varpi$ to the standard Newtonian/Einsteinian precessions of the perihelia of the inner planets recently estimated with the EPM ephemerides, compared to our predictions for them, yield K_1 = (4+8) 10^-26 s^-2, K_2 = (3+7) 10^-23 s^-2. The residuals of the Cassini-based Earth-Saturn range, compared with the numerically integrated LTB range signature, allow to obtain K_1/2 = 10^-27 s^-2. The LTB-induced distortions of the orbit of a typical object of the Oort cloud with respect to the commonly accepted Newtonian picture, based on the observations of the comet showers from that remote region of the solar system, point towards K_1/2 <= 10^-30-10^-32 s^-2. Such figures have to be compared with those inferred from cosmological data which are of the order of K1 \approx K2 = -4 10^-36 s^-2.Comment: LaTex2e, 18 pages, 3 tables, 3 figures. Minor changes. Reference added. Accepted by Journal of Cosmology and Astroparticle Physics (JCAP

Information Metric on Instanton Moduli Spaces in Nonlinear Sigma Models

We study the information metric on instanton moduli spaces in two-dimensional nonlinear sigma models. In the CP^1 model, the information metric on the moduli space of one instanton with the topological charge Q=k which is any positive integer is a three-dimensional hyperbolic metric, which corresponds to Euclidean anti--de Sitter space-time metric in three dimensions, and the overall scale factor of the information metric is (4k^2)/3; this means that the sectional curvature is -3/(4k^2). We also calculate the information metric in the CP^2 model.Comment: 9 pages, LaTeX; added references for section 1; typos adde

When unlikely outcomes occur: the role of communication format in maintaining communicator credibility

The public expects science to reduce or eliminate uncertainty (Kinzig & Starrett, 2003), yet scientific forecasts are probabilistic (at best) and it is simply not possible to make predictions with certainty. Whilst an ‘unlikely’ outcome is not expected to occur, an ‘unlikely’ outcome will still occur one in five times (based on a translation of 20%, e.g. Theil, 2002), according to a frequentist perspective. When an ‘unlikely’ outcome does occur, the prediction may be deemed ‘erroneous’, reflecting a misunderstanding of the nature of uncertainty. Such misunderstandings could have ramifications for the subsequent (perceived) credibility of the communicator who made such a prediction. We examine whether the effect of ‘erroneous’ predictions on perceived credibility differs according to the communication format used. Specifically, we consider verbal, numerical (point and range [wide / narrow]) and mixed format probability expressions. We consistently find that subsequent perceptions are least affected by the ‘erroneous’ prediction when it is expressed numerically, regardless of whether it is a point or range estimate. Our findings suggest numbers should be used in consequential risk communications regarding ‘unlikely’ events, wherever possible

Adaptation of Autocatalytic Fluctuations to Diffusive Noise

Evolution of a system of diffusing and proliferating mortal reactants is analyzed in the presence of randomly moving catalysts. While the continuum description of the problem predicts reactant extinction as the average growth rate becomes negative, growth rate fluctuations induced by the discrete nature of the agents are shown to allow for an active phase, where reactants proliferate as their spatial configuration adapts to the fluctuations of the catalysts density. The model is explored by employing field theoretical techniques, numerical simulations and strong coupling analysis. For d<=2, the system is shown to exhibits an active phase at any growth rate, while for d>2 a kinetic phase transition is predicted. The applicability of this model as a prototype for a host of phenomena which exhibit self organization is discussed.Comment: 6 pages 6 figur

Optical Spectra of SNR Candidates in NGC 300

We present moderate-resolution (<5A) long-slit optical spectra of 51 nebular objects in the nearby Sculptor Group galaxy NGC 300 obtained with the 2.3 meter Advanced Technology Telescope at Siding Spring Observatory, Australia. Adopting the criterion of [SII]/Ha>=0.4 to confirm supernova remnants (SNRs) from optical spectra, we find that of 28 objects previously proposed as SNRs from optical observations, 22 meet this criterion with six showing [SII]/Ha of less than 0.4. Of 27 objects suggested as SNRs from radio data, four are associated with the 28 previously proposed SNRs. Of these four, three (included in the 22 above) meet the criterion. In all, 22 of the 51 nebular objects meet the [SII]/Ha criterion as SNRs while the nature of the remaining 29 objects remains undetermined by these observations.Comment: Accepted for publication in Astrophysics & Space Scienc

Anisotropic Superparamagnetism of Monodispersive Cobalt-Platinum Nanocrystals

Based on the high-temperature organometallic route (Sun et al. Science 287, 1989 (2000)), we have synthesized powders containing CoPt_3 single crystals with mean diameters of 3.3(2) nm and 6.0(2) nm and small log-normal widths sigma=0.15(1). In the entire temperature range from 5 K to 400 K, the zero-field cooled susceptibility chi(T) displays significant deviations from ideal superparamagnetism. Approaching the Curie temperature of 450(10) K, the deviations arise from the (mean-field) type reduction of the ferromagnetic moments, while below the blocking temperature T_b, chi(T) is suppressed by the presence of energy barriers, the distributions of which scale with the particle volumes obtained from transmission electron microscopy (TEM). This indication for volume anisotropy is supported by scaling analyses of the shape of the magnetic absorption chi''(T,omega) which reveal distribution functions for the barriers being also consistent with the volume distributions observed by TEM. Above 200 K, the magnetization isotherms M(H,T) display Langevin behavior providing 2.5(1) mu_B per CoPt_3 in agreement with reports on bulk and thin film CoPt_3. The non-Langevin shape of the magnetization curves at lower temperatures is for the first time interpreted as anisotropic superparamagnetism by taking into account an anisotropy energy of the nanoparticles E_A(T). Using the magnitude and temperature variation of E_A(T), the mean energy barriers and 'unphysical' small switching times of the particles obtained from the analyses of chi''(T,omega) are explained. Below T_b hysteresis loops appear and are quantitatively described by a blocking model, which also ignores particle interactions, but takes the size distributions from TEM and the conventional field dependence of E_A into account.Comment: 12 pages with 10 figures and 1 table. Version accepted for publication in Phys. Rev. B . Two-column layou