Imagination as a Response to Naturalism: C.S. Lewis’s The Chronicles of Narnia in Light of the Anscombe Affair

In this paper I suggest The Chronicles of Narnia were occasioned by Elizabeth Anscombe’s critique of chapter three of Miracles. Instead of a retreat from debate, The Chronicles show that the Supernatural is not something to be contemplated, but instead experienced. In the stories, the children’s dominant naturalism and ignorance of Supernaturalism personally encounter the highest Supernatural being. When transitioning from Miracles to The Chronicles of Narnia, Lewis’s writing altered from operating under the Argument from Reason to the experience of imagination in order for the reader to personally experience – not contemplate – Supernaturalism. Fairytale, romance, and archetypes create the perfect framework for the reader to enjoy the hidden divinity of Supernaturalism in The Chronicles without distracting him with contemplation

Preface "Methods and strategies to evaluate landslide hazard and risk"

Federal Institute for Geosciences and Natural Resources, Hannover, GermanyThe special issue of Natural Hazards and Earth SystemSciences entitled "Methods and strategies to evaluatelandslide hazard and risk", which we had the fortune to edit,contains a selected set of contributions originally presentedat the General Assembly of the European GeosciencesUnion, in Vienna, Austria, on 13–18 April 2008. Themeeting proved to be a valuable opportunity to discussand compare methods, techniques and tools for discovering,evaluating, avoiding and mitigating landslide hazards andthe related risk. Novel approaches and case studies ofheuristic, statistical, and physically based models to evaluatelandslide hazards and risk at different geographical scalesand in different physiographic environments were presented.During the meeting, Theo van Asch, 2008 Sergey Solovievmedallist, gave an inspiring presentation on "Some issues andchallenges in landslide hazard modelling". This presentationsummarized the state-of-the-art, physically based landslidemodelling, and set the path for future research on thischallenging topic.The special issue contains six of the 29 oral and postercontributions originally presented and discussed by morethan 50authors at the meeting. The six papers cover alarge spectrum of topics, from site-specific investigationsto global-scale landslide hazard assessments. van Aschand Malet (2009) focused on the potential transition ofsliding blocks (slumps) into flow-like processes due tothe generation of excess pore water pressure in undrainedconditions. The generation of excess pore water pressuremay be the consequence of the deformation of the landslidebody during motion. The authors propose and discuss twomodel concepts that are tested on two slumps that havedeveloped in secondary scarps of the Super-Sauze mudslidein the Barcelonnette area, Southern Alps, France.Correspondence to: P. Reichenbach([email protected])Gunther and Thiel (2009) evaluated structurally-controlled¨failure susceptibility of fractured Cretaceous chalk rocks andtopographically-controlled shallow landslide susceptibilityof overlying glacial sediments in the Jasmund cliff area,Rugen Island, Germany. These authors adopted a combined¨methodology that involved spatially distributed kinematicalrock slope failure testing with tectonic fabric data, andphysically-based and inventory-based shallow landslidesusceptibility analyses. Romstad et al. (2009) presentedan innovative approach for regional hazard assessment ofNorwegian lakes exposed to tsunamis that can generatecatastrophic rockslides. The method successfully distin-guished between lakes with high and low rockslide potential.For each lake, the rockfall potential was determined basedon the topographical setting. For this reason, the rockfallpotential does not measure the probability of rockslides in thelakes. Van Den Eeckhaut et al. (2009) discussed a combinedlandslide inventory and susceptibility assessment based ondifferent mapping units carried out in the Flemish Ardennes,Belgium. The landslide susceptibility zonation was preparedthrough heuristic combination of, (i) a regional landslideinventory, (ii) a grid-cell-based map showing susceptibilityto landslide initiation, and (iii) a topographic-unit-based mapshowing the susceptibility to landslide spatial occurrence.Garc´ia-Rodr ´iguez and Malpica (2010) presented an approachfor assessing earthquake-triggered landslide susceptibilityusing artificial neural networks (ANN) in El Salvador.Modelling results were checked using independent landslideinformation, and revealed a good agreement between thelandslide inventory and the high susceptibility zoning. Thenew susceptibility zonation was compared critically to anexisting susceptibility zonation obtained through logisticregression analysis. Kirschbaum et al. (2009) presented apreliminary global landslide hazard algorithm developed toestimate areas of potential landslide occurrence in near real-time by combining a calculation of landslide susceptibilitywith satellite-derived rainfall estimates to forecast areas withPublished by Copernicus Publications on behalf of the European Geosciences Union

Entropy production of cyclic population dynamics

Entropy serves as a central observable in equilibrium thermodynamics. However, many biological and ecological systems operate far from thermal equilibrium. Here we show that entropy production can characterize the behavior of such nonequilibrium systems. To this end we calculate the entropy production for a population model that displays nonequilibrium behavior resulting from cyclic competition. At a critical point the dynamics exhibits a transition from large, limit-cycle like oscillations to small, erratic oscillations. We show that the entropy production peaks very close to the critical point and tends to zero upon deviating from it. We further provide analytical methods for computing the entropy production which agree excellently with numerical simulations.Comment: 4 pages, 3 figures and Supplementary Material. To appear in Phys. Rev. Lett.

Common Causes and The Direction of Causation

Is the common cause principle merely one of a set of useful heuristics for discovering causal relations, or is it rather a piece of heavy duty metaphysics, capable of grounding the direction of causation itself? Since the principle was introduced in Reichenbach’s groundbreaking work The Direction of Time (1956), there have been a series of attempts to pursue the latter program—to take the probabilistic relationships constitutive of the principle of the common cause and use them to ground the direction of causation. These attempts have not all explicitly appealed to the principle as originally formulated; it has also appeared in the guise of independence conditions, counterfactual overdetermination, and, in the causal modelling literature, as the causal markov condition. In this paper, I identify a set of difficulties for grounding the asymmetry of causation on the principle and its descendents. The first difficulty, concerning what I call the vertical placement of causation, consists of a tension between considerations that drive towards the macroscopic scale, and considerations that drive towards the microscopic scale—the worry is that these considerations cannot both be comfortably accommodated. The second difficulty consists of a novel potential counterexample to the principle based on the familiar Einstein Podolsky Rosen (EPR) cases in quantum mechanics

Rainfall induced landslides in December 2004 in south-western Umbria, central Italy: types, extent, damage and risk assessment

International audienceThe autumn of 2004 was particularly wet in Umbria, with cumulative rainfall in the period from October to December exceeding 600 mm. On 4?6 December and on 25?27 December 2004, two storms hit the Umbria Region producing numerous landslides, which were abundant near the town of Orvieto where they affected volcanic deposits and marine sediments. In this work, we document the type and abundance of the rainfall-induced landslides in the Orvieto area, in south-western Umbria, we study the rainfall conditions that triggered the landslides, including the timing of the slope failures, we determine the geotechnical properties of the failed volcanic materials, and we discuss the type and extent of damage produced by the landslides. We then use the recent event landslide information to test a geomorphological assessment of landslide hazards and risk prepared for the village of Sugano, in the Orvieto area. Based on the results of the test, we update the existing landslide hazards and risk scenario for extremely rapid landslides, mostly rock falls, and we introduce a new landslide scenario for rapid and very rapid landslides, including soil slides, debris flows and debris avalanches

All cause and disease specific mortality in patients with knee or hip osteoarthritis: Population based cohort study

Copyright © 2011 by the BMJ Publishing Group Ltd. This articles was first published in: BMJ, 2011, Vol. 342, Issue 7798, pp. 638 - 638To examine all cause and disease specific mortality in patients with osteoarthritis of the knee or hip

Impact of mapping errors on the reliability of landslide hazard maps

International audienceIdentification and mapping of landslide deposits are an intrinsically difficult and subjective operation that requires a great effort to minimise the inherent uncertainty. For the Staffora Basin, which extends for almost 300 km2 in the northern Apennines, three landslide inventory maps were independently produced by three groups of geomorphologists. In comparing each map with the others, large positional discrepancies arise (in the range of 55?65%). When all three maps are overlain, the locational mismatch of landslide deposit polygons increases to over 80%. To assess the impact of these errors on predictive models of landslide hazard, for the study area discriminant models were built up from the same set of geological-geomorphological factors as predictors, and the occurrence of landslide deposits within each terrain-unit, derived from each inventory map, as dependent variable. The comparison of these models demonstrates that statistical modelling greatly minimises the impact of input data errors which remain, however, a major limitation on the reliability of landslide hazard maps

Landslide hazard assessment in the Collazzone area, Umbria, Central Italy

We present the results of the application of a recently proposed model to determine landslide hazard. The model predicts where landslides will occur, how frequently they will occur, and how large they will be in a given area. For the Collazzone area, in the central Italian Apennines, we prepared a multi-temporal inventory map through the interpretation of multiple sets of aerial photographs taken between 1941 and 1997 and field surveys conducted in the period between 1998 and 2004. We then partitioned the 79 square kilometres study area into 894 slope units, and obtained the probability of spatial occurrence of landslides by discriminant analysis of thematic variables, including morphology, lithology, structure and land use. For each slope unit, we computed the expected landslide recurrence by dividing the total number of landslide events inventoried in the terrain unit by the time span of the investigated period. Assuming landslide recurrence was constant, and adopting a Poisson probability model, we determined the exceedance probability of having one or more landslides in each slope unit, for different periods. We obtained the probability of landslide size, a proxy for landslide magnitude, by analysing the frequency-area statistics of landslides, obtained from the multi-temporal inventory map. Lastly, assuming independence, we determined landslide hazard for each slope unit as the joint probability of landslide size, of landslide temporal occurrence, and of landslide spatial occurrence

Identification and mapping of recent rainfall-induced landslides using elevation data collected by airborne Lidar

International audienceA high resolution Digital Elevation Model with a ground resolution of 2 m×2 m (DEM2) was obtained for the Collazzone area, central Umbria, through weighted linear interpolation of elevation points acquired by Airborne Lidar Swath Mapping. Acquisition of the elevation data was performed on 3 May 2004, following a rainfall period that resulted in numerous landslides. A reconnaissance field survey conducted immediately after the rainfall period allowed mapping 70 landslides in the study area, for a total landslide area of 2.7×105 m2. Topographic derivative maps obtained from the DEM2 were used to update the reconnaissance landslide inventory map in 22 selected sub-areas. The revised inventory map shows 27% more landslides and 39% less total landslide area, corresponding to a smaller average landslide size. Discrepancies between the reconnaissance and the revised inventory maps were attributed to mapping errors and imprecision chiefly in the reconnaissance field inventory. Landslides identified exploiting the Lidar elevation data matched the local topography more accurately than the same landslides mapped using the existing topographic maps. Reasons for the difference include an incomplete or inaccurate view of the landslides in the field, an unfaithful representation of topography in the based maps, and the limited time available to map the landslides in the field. The high resolution DEM2 was compared to a coarser resolution (10 m×10 m) DEM10 to establish how well the two DEMs captured the topographic signature of landslides. Results indicate that the improved topographic information provided by DEM2 was significant in identifying recent rainfall-induced landslides, and was less significant in improving the representation of stable slopes