1,812 research outputs found

    The Meaning of Collective Terrorist Threat: Understanding the Subjective Causes of Terrorism Reduces Its Negative Psychological Impact

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    This article hypothesized that the possibility to construct intellectual meaning of a terrorist attack (i.e., whether participants can cognitively understand why the perpetrators did their crime) reduces the negative psychological consequences typically associated with increased terrorist threat. Concretely, the authors investigated the effect of intellectual meaning (induced by providing additional information about potential economic, cultural, and historical reasons for the terrorist attack) on perceived terrorist threat and associated emotional well-being. Study 1 revealed that pictures of terrorist attacks elicited less experienced terrorist threat when they were presented with background information about the terrorists’ motives (meaning provided) rather than without additional background information (no meaning provided). Study 2 replicated this effect with a different manipulation of terrorist threat (i.e., newspaper article) and clarified the underlying psychological process: Participants in the high terror salience condition with meaning provided experienced less terrorist threat and thus more emotional well-being in the face of crisis than participants in the high terror salience condition without meaning provided. Theoretical and practical implications in the context of psychological health and mass media effects are discussed

    Grouting Evaluation Program of the Best Methods for Use of Microfine and Portland Cements During Treatment of the Rock Foundation at the Portugues Dam

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    The U.S. Army Corps of Engineers, Jacksonville District, recently completed a grouting program in Ponce, Puerto Rico, for the Portugués Dam. The program compared microfine cement to Portland cement and helped determine the most efficient and economical method to construct the grout curtain. The foundation rock consists of volcanic sediments. A diorite stock upstream of the site altered the volcanic sediments by low grade metamorphism to metasediments, cause numerous radiating dikes and shears and a highly fractured foundation. Most of the fractures are relatively tight or healed. A bore hole video camera recorded in-situ fracture frequency, orientation and aperture thickness before and after grouting. The camera logs revealed that 58% of all the fractures were less than 0.02 inches thickness, the groutable limit for Portland cement. ln addition to standard Corps of Engineer water pressure tests, Modified Lugeon Pressure tests were conducted in exploratory core holes drilled after grouting. All of the pressure test data was then reduced to determine the rock mass permeability and compared with corresponding grout data. Various mix designs and pressures using both Portland and three microfine cements were experimented with. The standard injection refusal criteria time was adjusted and a Duration Grouting procedure, has been developed for the Portugués Dam

    Nullification functors and the homotopy type of the classifying space for proper bundles

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    Let G be a discrete group for which the classifying space for proper G-actions is finite-dimensional. We find a space W such that for any such G, the classifying space PBG for proper G-bundles has the homotopy type of the W-nullification of BG. We use this to deduce some results concerning PBG and in some cases where there is a good model for PBG we obtain information about the BZ/p-nullification of BG.Comment: Published by Algebraic and Geometric Topology at http://www.maths.warwick.ac.uk/agt/AGTVol5/agt-5-46.abs.htm

    Debris-flow release processes investigated through the analysis of multi-temporal LiDAR datasets in north-western Iceland

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    Debris flows are fast‐moving gravity flows of poorly sorted rock and soil, mixed and saturated with water. Debris‐flow initiation has been studied using empirical and experimental modelling, but the geomorphic changes, indicative of different triggering processes, are difficult to constrain with field observations only. We identify signatures to distinguish two different debris‐flow release styles by integrating high‐resolution multi‐temporal remote sensing datasets and morphometric analysis. We analyse debris flows sourced above the town of ÍsafjörĂ°ur (Iceland). Two debris‐flow triggering processes were previously hypothesized for this site: (i) slope failure, characterised by landslides evolving into debris flows, and (ii) the fire‐hose effect, in which debris accumulated in pre‐existing, steep‐sided bedrock passages is transported by a surge of water. It is unknown which process dominates and determines the local risk. To investigate this question, we compare airborne LiDAR elevation models and aerial photographs collected in 2007 with similar data from 2013. We find that two new debris‐flow tracks were created by slope failures. These are characterised by steep sliding surfaces and lateral leveed channels. Slope failure also occurred in two large, recently active tracks, creating the preparatory conditions for the fire‐hose effect to mobilise existing debris. These tracks show alternating zones of fill and scour along their length, and debris stored below the source‐area at rest angles >35°. Our approach allows us to identify and quantify the morphological changes produced by slope failure release process, which generated the preparatory conditions for the fire‐hose effect. As debris flows are rarely observed in action and morphological changes induced by them are difficult to detect and monitor, the same approach could be applied to other landscapes to understand debris‐flow initiation in absence of other monitoring information, and can improve the identification of zones at risk in inhabited areas near hillslopes with potential for debris flows

    The millenium ark: How long a voyage, how many staterooms, how many passengers?

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    Barring holocausts, demographic forecasts suggest a “demographic winter” lasting 500–1,000 years and eliminating most habitat for wildlife in the tropics. About 2,000 species of large, terrestrial animals may have to be captively bred if they are to be saved from extinction by the mushrooming human population. Improvements in biotechnology may facilitate the task of protecting these species, but it probably will be decades at least before cryotechnology per se is a viable alternative to captive breeding for most species of endangered wildlife. We suggest that a principle goal of captive breeding be the maintenance of 90% of the genetic variation in the source (wild) population over a period of 200 years. Tables are provided that permit the estimation of the ultimate minimum size of the captive group, given knowledge of the exponential growth rate of the group, and the number of founders. In most cases, founder groups will have to be above 20 (effective) individuals.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/38475/1/1430050205_ftp.pd

    DNA diet profiles with high‐resolution animal tracking data reveal levels of prey selection relative to habitat choice in a crepuscular insectivorous bird

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    Given the global decline of many invertebrate food resources, it is fundamental to understand the dietary requirements of insectivores. We give new insights into the functional relationship between the spatial habitat use, food availability, and diet of a crepuscular aerial insectivore, the European Nightjar (Caprimulgus europaeus) by relating spatial use data with high‐throughput sequencing (HTS) combined with DNA metabarcoding. Our study supports the predictions that nightjars collect a substantial part of their daily nourishment from foraging locations, sometimes at considerable distance from nesting sites. Lepidopterans comprise 65% of nightjars' food source. Nightjars tend to select larger species of Lepidoptera (>19 mm) which suggests that nightjars optimize the efficiency of foraging trips by selecting the most energetically favorable—larger—prey items. We anticipate that our findings may shed additional light on the interactions between invertebrate communities and higher trophic levels, which is required to understand the repercussions of changing food resources on individual‐ and population‐level processes

    The efficacy of a nanosynthetic bone graft substitute as a bone graft extender in rabbit posterolateral fusion

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    Funding Disclosure(s) Statement: This study was partly funded by a grant from Innovate UK (Grant no. 103853), awarded to Sirakoss Ltd., with the remaining study costs provided by Sirakoss Ltd.Peer reviewedPublisher PD

    Molards as an indicator of permafrost degradation and landslide processes

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    Molards have been defined in the past as conical mounds of debris that can form part of a landslide's deposits. We present the first conclusive evidence that molards in permafrost terrains are cones of loose debris that result from thawing of frozen blocks of ice-rich sediments mobilised by a landslide, and hence propose a rigorous definition of this landform in permafrost environments. We show that molards can be used as an indicator of permafrost degradation, and that their morphometry and spatial distribution give valuable insights into landslide dynamics in permafrost environments. We demonstrate that molards are readily recognisable not only in the field, but also in remote sensing data; surveys of historic aerial imagery allow the recognition of relict molards, which can be used as an indicator of current and past permafrost conditions. The triggering of landslides as a result of permafrost degradation will arguably occur more often as global atmospheric temperatures increase, so molards should be added to our armoury for tracking climate change, as well as helping us to understand landslide-related hazards. Finally, we have also identified candidate molards on Mars, so molards can inform about landscape evolution on Earth and other planetary bodies
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