Shatter cones: Diagnostic impact signatures

Uniquely fractured target rocks known as shatter cones are associated with more than one half the world's 120 or so presently known impact structures. Shatter cones are a form of tensile rock failure in which a positive conical plug separates from a negative outer cup or mold and delicate ornaments radiating from an apex are preserved on surfaces of both portions. Although distinct, shatter cones are sometimes confused with other striated geologic features such as ventifacts, stylolites, cone-in-cone, slickensides, and artificial blast plumes. Complete cones or solitary cones are rare, occurrences are usually as swarms in thoroughly fractured rock. Shatter cones may form in a zone where an expanding shock wave propagating through a target decays to form an elastic wave. Near this transition zone, the expanding primary wave may strike a pebble or other inhomogeneity whose contrasting transmission properties produce a scattered secondary wave. Interference between primary and secondary scattered waves produce conical stress fields with axes perpendicular to the plane of an advancing shock front. This model supports mechanism capable of producing such shatter cone properties as orientation, apical clasts, lithic dependence, and shock pressure zonation. Although formational mechanics are still poorly understood, shatter cones have become the simplest geologic field criterion for recognizing astroblemes (ancient terrestrial impact structures)

Observing workplace incivility towards women: The roles of target reactions, actor motives, and actor-target relationships

The current study conceptualized observer reactions to uncivil behavior towards women as an ethical behavior and examined three factors (target reaction, actor motive, and actor-target relationship) that influence these reactions. Two vignette studies with women and men undergraduate and graduate students in western Switzerland were conducted. Study 1 (N=148) was a written vignette study that assessed how the reaction of female targets to incivility and the motives of actors influenced observer reactions. Results showed that a female target's reaction influenced observers' evaluations of the harm caused by an uncivil incident, and that an actor's motive affected observers' assessments of the necessity to intervene. Study 2 (N=81) was a video vignette study that assessed the effects of the reactions by female targets to incivility and the relationship between the target and the actor on observer reactions.We found that female targets' reactions influenced observers' evaluations of harm and the perceived necessity to intervene. Furthermore, the effect of a female target's reaction on observers' evaluations of harm was moderated by the relationship between the actor and the target: a female target who laughed at the uncivil behavior was perceived as less harmed, when she and the actor had a personal relationship than when they had a professional relationship. When the female target reacted hurt or neutrally, actor-target relationship did not affect observers' evaluations of harm. We conclude by discussing the implications of our findings for theory and practice

Satellite power system: Concept development and evaluation program. Volume 3: Power transmission and reception. Technical summary and assessment

Efforts in the DOE/NASA concept development and evaluation program are discussed for the solar power satellite power transmission and reception system. A technical summary is provided together with a summary of system assessment activities. System options and system definition drivers are described. Major system assessment activities were in support of the reference system definition, solid state system studies, critical technology supporting investigations, and various system and subsystem tradeoffs. These activities are described together with reference system updates and alternative concepts for each of the subsystem areas. Conclusions reached as a result of the numerous analytical and experimental evaluations are presented. Remaining issues for a possible follow-on program are identified

Teaching Aids in Botany. I - The Placement Test

The written placement test has proven a valuable teaching aid in General Botany at Iowa State College, particularly when used to segregate students into high, medium, or low sections. In the fall of 1938 it was used to segregate 350 students into 5 high, 2 medium and 5 low sections. The administrative difficulties of sectioning were met by placing the 90 students who were classified for the same class period into 3 sections of about 30 each. This test has been evolved over a period of ten years; and is composed of ten comprehensive questions of the following types: information, interpretation of data, testing of hypotheses, methods of proof and deductive reasoning. The effectiveness of the placement test is indicated by a correlation of .57 between it and the comprehensive final examination administered to 323 students in the fall of 1938

A Multi-Criteria Methodology for Measuring the Resilience of Transportation Assets and Prioritizing Security Investments

Transportation project prioritization uses performance measures that are related to the transportation asset, its operations, and its environment. However, in the state of practice, evaluation does not consider directly the likelihood of natural or man-made threats, the infrastructure resilience, or the consequences of the infrastructure damage in the event that the threat occurs. Thus, during the prioritization of investments, assets of low security do not receive the due attention they deserve. In defining security as the lack of risk of damage from threats due to inherent structure or functional resilience, this paper is based on the premise that the inclusion of security considerations in prioritization introduces a much needed element of robustness in investment prioritization However, the inclusion of investment security impacts leads to an increase in the number of performance measures for the investment evaluation. This paper presents a methodology to quantify the overall security level for an asset in terms of the environmental threats it faces, its resilience or vulnerability to damage, and the consequences of the infrastructure damage. The overall framework consists of the traditional steps in risk management, and this paper\u27s specific contribution is in the part of the framework that measures the risk. This paper applies the methodology to a given set of assets by measuring the risk (security) of each asset and prioritizing security investments across multiple assets using multiple criteria analysis

Optimizing passive acoustic sampling of bats in forests

Passive acoustic methods are increasingly used in biodiversity research and monitoring programs because they are cost-effective and permit the collection of large datasets. However, the accuracy of the results depends on the bioacoustic characteristics of the focal taxa and their habitat use. In particular, this applies to bats which exhibit distinct activity patterns in three-dimensionally structured habitats such as forests. We assessed the performance of 21 acoustic sampling schemes with three temporal sampling patterns and seven sampling designs. Acoustic sampling was performed in 32 forest plots, each containing three microhabitats: forest ground, canopy, and forest gap. We compared bat activity, species richness, and sampling effort using species accumulation curves fitted with the clench equation. In addition, we estimated the sampling costs to undertake the best sampling schemes. We recorded a total of 145,433 echolocation call sequences of 16 bat species. Our results indicated that to generate the best outcome, it was necessary to sample all three microhabitats of a given forest location simultaneously throughout the entire night. Sampling only the forest gaps and the forest ground simultaneously was the second best choice and proved to be a viable alternative when the number of available detectors is limited. When assessing bat species richness at the 1-km(2) scale, the implementation of these sampling schemes at three to four forest locations yielded highest labor cost-benefit ratios but increasing equipment costs. Our study illustrates that multiple passive acoustic sampling schemes require testing based on the target taxa and habitat complexity and should be performed with reference to cost-benefit ratios. Choosing a standardized and replicated sampling scheme is particularly important to optimize the level of precision in inventories, especially when rare or elusive species are expected

Experimental Test of a Two-dimensional Approximation for Dielectric Microcavities

Open dielectric resonators of different shapes are widely used for the manufacture of microlasers. A precise determination of their resonance frequencies and widths is crucial for their design. Most microlasers have a flat cylindrical geometry, and a two-dimensional approximation, the so-called method of the effective index of refraction, is commonly employed for numerical calculations. Our aim has been an experimental test of the precision and applicability of a model based on this approximation. We performed very thorough and accurate measurements of the resonance frequencies and widths of two passive circular dielectric microwave resonators and found significant deviations from the model predictions. From this we conclude that the model generally fails in the quantitative description of three-dimensional dielectric resonators.Comment: 10 pages, 13 figure

Document Filtering for Long-tail Entities

Filtering relevant documents with respect to entities is an essential task in the context of knowledge base construction and maintenance. It entails processing a time-ordered stream of documents that might be relevant to an entity in order to select only those that contain vital information. State-of-the-art approaches to document filtering for popular entities are entity-dependent: they rely on and are also trained on the specifics of differentiating features for each specific entity. Moreover, these approaches tend to use so-called extrinsic information such as Wikipedia page views and related entities which is typically only available only for popular head entities. Entity-dependent approaches based on such signals are therefore ill-suited as filtering methods for long-tail entities. In this paper we propose a document filtering method for long-tail entities that is entity-independent and thus also generalizes to unseen or rarely seen entities. It is based on intrinsic features, i.e., features that are derived from the documents in which the entities are mentioned. We propose a set of features that capture informativeness, entity-saliency, and timeliness. In particular, we introduce features based on entity aspect similarities, relation patterns, and temporal expressions and combine these with standard features for document filtering. Experiments following the TREC KBA 2014 setup on a publicly available dataset show that our model is able to improve the filtering performance for long-tail entities over several baselines. Results of applying the model to unseen entities are promising, indicating that the model is able to learn the general characteristics of a vital document. The overall performance across all entities---i.e., not just long-tail entities---improves upon the state-of-the-art without depending on any entity-specific training data.Comment: CIKM2016, Proceedings of the 25th ACM International Conference on Information and Knowledge Management. 201

eine ethnographische Annäherung

Wie denken BerlinerInnen über die Zukunft ihrer Stadt? Was sind ihre Wünsche, was mögliche Zukunftsängste? Studierende des Masterstudiums Zukunftsforschung haben Antworten auf diese Fragen gesucht und sich in verschiedenen Milieus der Stadt aufgehalten, um – angelehnt an den ethnographischen Ansatz der teilnehmenden Beobachtung – mit den Menschen vor Ort intensive Gespräche zu führen. Sechs Gruppen standen dabei im Fokus: die Gäste und BetreiberInnen alteingesessener Kneipen in Berliner Szenekiezen, TaxifahrerInnen, BewohnerInnen eines Mehrfamilienhauses in Berlin-Pankow, homosexuelle Männer, VerkäuferInnen des Obdachlosenmagazins »Straßenfeger« sowie junge UnternehmerInnen aus dem Bereich der »Social Startups«. Herausgekommen sind einzigartige Blicke auf die Zukunft Berlins, die aus teilweise vernachlässigten Perspektiven vielfältige Hoffnungen, Erwartungen und Ängste von BerlinerInnen zeigen. Die »Gespräche« zeigen, dass die von ihrer jeweils eigenen Geschichte und sozialen Gegenwart geprägten »subkulturellen« Zukunftsbilder eine elementare Rolle für die Wahrnehmung von Berlin spielen. Zentral in allen Zukunftsvorstellungen ist dabei die Auseinandersetzung mit dem zukünftigen Zusammenleben unter den Bedingungen eines sich stetig wandelnden sozialen Umfelds. Das Konzept und die Umsetzung entstand im Wintersemester 2014/15 in einer Übung im »Einsatzfeld Gesellschaft« des Masterstudiengangs Zukunftsforschung an der Freien Universität Berlin, geleitet von Björn Theis