Coherent

Distribution by Scientific Domains

Terms modified by Coherent

  • coherent account
  • coherent anti-Stoke raman scattering
  • coherent approach
  • coherent control
  • coherent detection
  • coherent diffraction
  • coherent framework
  • coherent model
  • coherent pattern
  • coherent phonon
  • coherent picture
  • coherent potential approximation
  • coherent risk measure
  • coherent signal
  • coherent structure
  • coherent superposition
  • coherent system
  • coherent way
  • coherent x-ray

  • Selected Abstracts


    The Contribution of Bioenergy to a New Energy Paradigm

    EUROCHOICES, Issue 3 2005
    Daniel De La Torre Ugarte
    Biomass is a widely available resource that is receiving increased consideration as a renewable substitute for fossil fuels. Developed sustainably and used efficiently, it can induce growth in developing countries, reduce oil demand, and address environmental problems. The potential benefits include: reduction of greenhouse gases, recuperation of soil productivity and degraded land, economic benefits from adding value to agricultural activities and improving access to and quality of energy services. The production of bioenergy involves a range of technologies, including solid combustion, gasification, and fermentation. These technologies produce energy from a diverse set of biological resources - traditional crops, crop residues, energy-dedicated crops, dung, and the organic component of urban waste. The results are bioenergy products that provide multiple energy services: cooking fuel, heat, electricity and transportation fuels. It is this very diversity that holds the potential of a win-win-win for the environment, social and economic development. Bioenergy has to be viewed not as a replacement for oil, but as an element of a portfolio of renewable sources of energy. Coherent and mutually supportive environmental and economic policies may be needed to encourage the emergence of a globally dispersed bioenergy industry that will pursue a path of sustainable development. La biomasse est une resource largement répandue, qui commence à retenir l'attention comme substitut renouvelable aux énergies fossiles. En l'utilisant de façon efficace et durable, on peut accélérer la croissance des pays en voie de développement, réduire la demandepour le pétrole et résoudre certains problèmes d'environnement. Au nombre des bénéfices potentiels il faut mettre : la réduction des émissions de gaz à effet de serre, la reconstitution de la fertilité dessols et des terres dégradées, les avantages économiques liés à l'accroissement de la production agricole et à l'amélioration des services énergétiques, tant en qualité qu'en accessibilité. La production de bioénergie met en oeuvre un large éventail de techniques parmi lesquelles la combustionde produits solides, la gazéification et la fermentation. Elles produisent de l'énergie à partir d'une grande variété de sources biologiques : cultures traditionnelles, résidus de cultures, cultures spécialisées, fumiers et déchets organiques urbains. Les produits bio-énergétiques qui en résultent couvrent une grande variété d'usages : énergie de cuisson, chauffage, électricité et transports. C'est précisément sur cette diversité que repose l'espoir de gains dans toutes les directions, sociales, environnementales et économiques. Il ne faut pas voir la bioénergie comme un simple substitut au pétrole, mais comme un portefeuille de ressources renouvelables. Pour encourager l'émergence d'une industrie bioénergétique largement répandue et susceptible de contribuer au développement durable, il faudra sans doute élaborer des politiques économiques et environnementales cohérentes, capables de se soutenir mutuellement. Bei Biomasse handelt es sich umeine weithin verfügbare Ressource, welche zunehmend als erneuerbarer Ersatz für fossile Brennstoffe in Betracht gezogen wird. Sie kann bei nachhaltiger Entwicklung und effizienter Nutzung zu Wachstum in den Entwicklungsländern führen, die Nachfrage nach Öl senken und dazu beitragen, die Umweltprobleme in den Griff zu bekommen. Zu den potenziellen Nutzen gehÖren: Verringerung der Treibhausgase, Wiederherstellung von Bodenproduktivität sowie von erodiertem Land, wirtschaftlicher Nutzen durch zusätzliche Wertschöpfung aus landwirtschaftlicher Aktivität und besserer Zugang zu und Qualität in der Energieversorgung. Bei der Erzeugungvon Bioenergie kommen eine Reihe von verschiedenen Technologien zur Anwendung, z.B. Verbrennung fester Brennstoffe, Vergasung sowie Gärung. Diese Technologien erzeugen Energie mittels unterschiedlicher biologischer Ressourcen , traditionelle Feldfrüchte und deren Rückstände, spezielle Energiepflanzen, Mist sowie der organische Anteil städtischer Abfälle. Die daraus erzeugte Bioenergie kann zum Kochen, zum Heizen, als Elektrizität oder als Treibstoff genutzt werden. Gerade in dieser Vielfalt liegt der potenzielle Gewinn für die Umwelt und die soziale sowie die wirtschaftliche Entwicklung. Bioenergie sollte nicht als ein Ersatz für Öl, sondern als Bestandteil des Portfolios erneuerbarer Energiequellen angesehen werden. Kohärente und sich gegenseitig unterstützende ökologische und Ökonomische Politikmaßnahmen könntenerforderlich sein, um die Entstehung einer global verbreiteten Bioenergieindustrie zu begünstigen, welche eine nachhaltige Entwicklung verfolgt. [source]


    John Wiley & Sons: 200th anniversary!

    LASER TECHNIK JOURNAL, Issue 1 2007
    Andreas Thoß Dr.
    This year, the publisher John Wiley & Sons celebrates its 200th anniversary. When Charles Wiley first opened his print shop in lower Manhattan in 1807, America was a young nation, full of potential and seeking its cultural identity on the global stage. Wiley was there, contributing to the emerging American literary tradition by publishing such great 19th century American writers as James Fenimore Cooper, Washington Irving, Herman Melville, and Edgar Allan Poe. Later on, Wiley published the works of outstanding European writers such as Hans Christian Andersen, Charles Dickens, John Ruskin, and Elizabeth Barrett Browning. Yet, during the second industrial revolution , and its resulting knowledge revolution , Wiley abandoned its literary programme to pursue knowledge publishing for a global community. Today Wiley publishes a broad variety of journals, encyclopedias, books, and online products. The spectrum reaches from medicine to astronomy, from trade journals to consumer books and it includes educational materials for students as well as for lifelong learners. Since 1807, the world has seen 41 U.S. Presidents, but there have only been ten Wiley Presidents. Today, Wiley is a publicly held, independently managed family business. That is the formula of success that has sustained the company for two centuries. In 2007 Wiley is one of the major global publishers with more than one billion dollar revenue and about 3.900 employees. This will increase even more, when the acquisition of Blackwell Publishing will be completed in 2007. Aged only three years, the Laser Technik Journal is one of the youngest among the Wiley Journals. But it fits well in the history of Wiley. Thomas Alva Edison, the "Wizard of Menlo Park", held William H. Wiley in high regard, and so there is a long tradition of close contacts between the publishing house and the engineering community. The purpose of the journals has changed little: Our mission is to provide the community with up to date information on the latest in technology, reports and discussions on trends and markets, and finally the journal serves as a forum for key people from science and business to share their visions and experiences. 2007 will be a great year not only for Wiley, but for the laser community as well. Company reports from Coherent, Trumpf or Rofin Sinar show two-digit growths and excellent earnings. Record numbers are expected also at conferences and trade shows. At Photonics West in San Jose, CA, 1.000 exhibitors and more than 15.000 visitors are expected. The Laser. World of Photonics 2007 in Munich (June) will be even bigger. It is a "can't miss" event particularly for those visitors interested in Laser material processing. The Laser Technik Journal will be on both shows. Please stop by at the Wiley booth, for a chat or to see the latest from the Wiley book program! [source]


    RISK MEASURES ON ORLICZ HEARTS

    MATHEMATICAL FINANCE, Issue 2 2009
    Patrick Cheridito
    Coherent, convex, and monetary risk measures were introduced in a setup where uncertain outcomes are modeled by bounded random variables. In this paper, we study such risk measures on Orlicz hearts. This includes coherent, convex, and monetary risk measures on Lp -spaces for 1 ,p < , and covers a wide range of interesting examples. Moreover, it allows for an elegant duality theory. We prove that every coherent or convex monetary risk measure on an Orlicz heart which is real-valued on a set with non-empty algebraic interior is real-valued on the whole space and admits a robust representation as maximal penalized expectation with respect to different probability measures. We also show that penalty functions of such risk measures have to satisfy a certain growth condition and that our risk measures are Luxemburg-norm Lipschitz-continuous in the coherent case and locally Luxemburg-norm Lipschitz-continuous in the convex monetary case. In the second part of the paper we investigate cash-additive hulls of transformed Luxemburg-norms and expected transformed losses. They provide two general classes of coherent and convex monetary risk measures that include many of the currently known examples as special cases. Explicit formulas for their robust representations and the maximizing probability measures are given. [source]


    Choosing Rhetorical Structures To Plan Instructional Texts

    COMPUTATIONAL INTELLIGENCE, Issue 3 2000
    Leila Kosseim
    This paper discusses a fundamental problem in natural language generation: how to organize the content of a text in a coherent and natural way. In this research, we set out to determine the semantic content and the rhetorical structure of texts and to develop heuristics to perform this process automatically within a text generation framework. The study was performed on a specific language and textual genre: French instructional texts. From a corpus analysis of these texts, we determined nine senses typically communicated in instructional texts and seven rhetorical relations used to present these senses. From this analysis, we then developed a set of presentation heuristics that determine how the senses to be communicated should be organized rhetorically in order to create a coherent and natural text. The heuristics are based on five types of constraints: conceptual, semantic, rhetorical, pragmatic, and intentional constraints. To verify the heuristics, we developed the spin natural language generation system, which performs all steps of text generation but focuses on the determination of the content and the rhetorical structure of the text. [source]


    Strategies in Human Nonmonotonic Reasoning

    COMPUTATIONAL INTELLIGENCE, Issue 3 2000
    Marilyn Ford
    Although humans seem adept at drawing nonmonotonic conclusions, the nonmonotonic reasoning systems that researchers develop are complex and do not function with such ease. This paper explores people's reasoning processes in nonmonotonic problems. To avoid the problem of people's conclusions being based on knowledge rather than on some reasoning process, we developed a scenario about life on another planet. Problems were chosen to allow the systematic study of people's understanding of strict and nonstrict rules and their interactions. We found that people had great difficulty reasoning and we identified a number of negative factors influencing their reasoning. We also identified three positive factors which, if used consistently, would yield rational and coherent reasoning,but no subject achieved total consistency. (Another possible positive factor, specificity, was considered but we found no evidence for its use.) It is concluded that nonmonotonic reasoning is hard. When people need to reason in a domain where they have no preconceived ideas, the foundation for their reasoning is neither coherent nor rational. They do not use a nonmonotonic reasoning system that would work regardless of content. Thus, nonmonotonic reasoning systems that researchers develop are expected to do more reasoning than humans actually do! [source]


    An Exploratory Technique for Coherent Visualization of Time-varying Volume Data

    COMPUTER GRAPHICS FORUM, Issue 3 2010
    A. Tikhonova
    Abstract The selection of an appropriate global transfer function is essential for visualizing time-varying simulation data. This is especially challenging when the global data range is not known in advance, as is often the case in remote and in-situ visualization settings. Since the data range may vary dramatically as the simulation progresses, volume rendering using local transfer functions may not be coherent for all time steps. We present an exploratory technique that enables coherent classification of time-varying volume data. Unlike previous approaches, which require pre-processing of all time steps, our approach lets the user explore the transfer function space without accessing the original 3D data. This is useful for interactive visualization, and absolutely essential for in-situ visualization, where the entire simulation data range is not known in advance. Our approach generates a compact representation of each time step at rendering time in the form of ray attenuation functions, which are used for subsequent operations on the opacity and color mappings. The presented approach offers interactive exploration of time-varying simulation data that alleviates the cost associated with reloading and caching large data sets. [source]


    "Visible Signs of a City Out of Control": Community Policing in New York City

    CULTURAL ANTHROPOLOGY, Issue 2 2004
    Benjamin Chesluk
    ABSTRACT Institutions of police,community dialogue in New York City assume that communities possess an intuitive and legally sound sense of order and disorder, on which the police can rely for information and support. However, staged dialogues between police and community groups can produce complicated situations of conflict and tension. While the police work to interpellate a friendly, coherent, and controlled community subject, city residents use the police's ideological language of order to offer a critique of the police themselves and of the sweeping neoliberal economic restructuring of the city around them. [source]


    Children's narratives and patterns of cardiac reactivity

    DEVELOPMENTAL PSYCHOBIOLOGY, Issue 4 2004
    Yair Bar-Haim
    Abstract The present study examines the associations between narrative processing, narrative production, and cardiac rate and variability in children. Heart period (HP) and vagal tone (VT) were computed for fifty-eight 7-year-olds (29 males) during a resting baseline and during epochs in which the children listened to and completed a selected set of story-stems from the MacArthur Story-Stem Battery (I. Bretherton, D. Oppenheim, H. Buchsbaum, R. N. Emde, & the MacArthur Narrative Group, 1990). Significant decreases in HP and VT were observed between a resting baseline and epochs of story-stem presentation by the experimenter. In addition, HP was shorter and VT lower during children's narrative production to emotionally laden story-stems compared with narration to a neutral story-stem. Furthermore, narrative and cardiac responses to stories containing separation,reunion themes reflected increased emotional and cognitive load compared with responses to stories that did not contain such themes. Finally, children who showed VT suppression in response to emotion-laden stories produced more coherent and adaptive narratives compared to those of children who did not show VT suppression. The findings suggest interplay between the cognitive-emotional processes associated with narrative processing and production and cardiac activation patterns. © 2004 Wiley Periodicals, Inc. Dev Psychobiol 44: 238,249, 2004. [source]


    The bone histology of osteoderms in temnospondyl amphibians and in the chroniosuchian Bystrowiella

    ACTA ZOOLOGICA, Issue 1 2010
    Florian Witzmann
    Abstract Witzmann, F. and Soler-Gijón, R. 2010. The bone histology of osteoderms in temnospondyl amphibians and in the chroniosuchian Bystrowiella. ,Acta Zoologica (Stockholm) 91: 96,114 Bone histology of osteoderms in the armoured temnospondyl Peltobatrachus, plagiosaurids (Gerrothorax, Plagiosuchus) and dissorophids (Aspidosaurus, Cacops, Platyhystrix), as well as in the chroniosuchian Bystrowiella, is studied. The massive osteoderms of Peltobatrachus and Gerrothorax consist of homogeneous parallel-fibred bone, whereas in dissorophids, a lightly built, trabecular middle region is mantled by a thin cortex that is composed of a plywood-type structure. In Bystrowiella and Plagiosuchus, the osteoderms consist to a large degree of interwoven primary fibres and have cell lacunae that bear stumpy canaliculi. The differences in the histological structure of dissorophids and plagiosaurids suggest an iterative evolution of osteoderms. Furthermore, histology in Plagiosuchus indicates a metaplastic development of the osteoderms, whereas the osteoderms of Gerrothorax represent periosteal ossifications as in dissorophids. This suggests a convergent origin of osteoderms also within plagiosaurids. The extensive armour in Gerrothorax probably constituted a calcium reservoir, indicated by cyclical resorption events preserved in the external cortex and interpreted as a physiological response to periodic changes in salinity of the aquatic environment. In contrast, the unique osteoderm structure of dissorophids provides maximum stability and minimum bone mass, and is coherent with the interpretation that the osteoderms served to strengthen the vertebral column during terrestrial locomotion. [source]


    Spectrally based remote sensing of river bathymetry

    EARTH SURFACE PROCESSES AND LANDFORMS, Issue 8 2009
    Carl J. Legleiter
    Abstract This paper evaluates the potential for remote mapping of river bathymetry by (1) examining the theoretical basis of a simple, ratio-based technique for retrieving depth information from passive optical image data; (2) performing radiative transfer simulations to quantify the effects of suspended sediment concentration, bottom reflectance, and water surface state; (3) assessing the accuracy of spectrally based depth retrieval under field conditions via ground-based reflectance measurements; and (4) producing bathymetric maps for a pair of gravel-bed rivers from hyperspectral image data. Consideration of the relative magnitudes of various radiance components allowed us to define the range of conditions under which spectrally based depth retrieval is appropriate: the remotely sensed signal must be dominated by bottom-reflected radiance. We developed a simple algorithm, called optimal band ratio analysis (OBRA), for identifying pairs of wavelengths for which this critical assumption is valid and which yield strong, linear relationships between an image-derived quantity X and flow depth d. OBRA of simulated spectra indicated that water column optical properties were accounted for by a shorter-wavelength numerator band sensitive to scattering by suspended sediment while depth information was provided by a longer-wavelength denominator band subject to strong absorption by pure water. Field spectra suggested that bottom reflectance was fairly homogeneous, isolating the effect of depth, and that radiance measured above the water surface was primarily reflected from the bottom, not the water column. OBRA of these data, 28% of which were collected during a period of high turbidity, yielded strong X versus d relations (R2 from 0·792 to 0·976), demonstrating that accurate depth retrieval is feasible under field conditions. Moreover, application of OBRA to hyperspectral image data resulted in spatially coherent, hydraulically reasonable bathymetric maps, though negative depth estimates occurred along channel margins where pixels were mixed. This study indicates that passive optical remote sensing could become a viable tool for measuring river bathymetry. Copyright © 2009 John Wiley & Sons, Ltd. [source]


    Near-fault ground motions, and the response of elastic and inelastic single-degree-of-freedom (SDOF) systems

    EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 9 2004
    G. P. Mavroeidis
    Abstract In order to investigate the response of structures to near-fault seismic excitations, the ground motion input should be properly characterized and parameterized in terms of simple, yet accurate and reliable, mathematical models whose input parameters have a clear physical interpretation and scale, to the extent possible, with earthquake magnitude. Such a mathematical model for the representation of the coherent (long-period) ground motion components has been proposed by the authors in a previous study and is being exploited in this article for the investigation of the elastic and inelastic response of the single-degree-of-freedom (SDOF) system to near-fault seismic excitations. A parametric analysis of the dynamic response of the SDOF system as a function of the input parameters of the mathematical model is performed to gain insight regarding the near-fault ground motion characteristics that significantly affect the elastic and inelastic structural performance. A parameter of the mathematical representation of near-fault motions, referred to as ,pulse duration' (TP), emerges as a key parameter of the problem under investigation. Specifically, TP is employed to normalize the elastic and inelastic response spectra of actual near-fault strong ground motion records. Such normalization makes feasible the specification of design spectra and reduction factors appropriate for near-fault ground motions. The ,pulse duration' (TP) is related to an important parameter of the rupture process referred to as ,rise time' (,) which is controlled by the dimension of the sub-events that compose the mainshock. Copyright © 2004 John Wiley & Sons, Ltd. [source]


    Measuring Monetary Policy Shocks in a Small Open Economy

    ECONOMIC NOTES, Issue 1 2001
    Giuseppe De Arcangelis
    This paper presents different specifications of a structural VAR model which are useful to identify monetary policy shocks and their macroeconomic effects for the Italian economy in the 1990s. The analysis is based on a detailed institutional description of the functioning of the domestic market for bank reserves. In this setting, we try to establish if monetary policy shocks are better identified using exchange rates or foreign exchange reserves as a conditioning variable for the small open economy framework. Our analysis confirms the view that the Bank of Italy has been targeting the rate on overnight interbank loans in the 1990s. This is coherent with either proposed modelling choices. Therefore, we interpret shocks to the overnight rate as purely exogenous monetary policy shocks and study how they impact the economy. (J.E.L.: E52, F41, F47). [source]


    Energy tax harmonization in the European Union: a proposal based on the internalization of environmental external costs

    ENVIRONMENTAL POLICY AND GOVERNANCE, Issue 1 2002
    Susanna Dorigoni
    Energy tax harmonization represents a fundamental target within the European Union. In fact fiscal harmonization is a crucial step towards the creation of a single market. In this article the possibility of achieving such an objective is discussed. The paper consists of two sections. In the first the European taxation on energy products is analysed. This analysis is useful in showing the differences that exist between the European countries that account for the difficulties met so far in the process of harmonization. In this respect we comment on the recent proposal of the Directive of the European Union, which lays down the obligation of minimum levels of taxation in all European member states. In the second section, after simulating the effects related to the adoption of a common environmental taxation (a first best solution based on the internalization of environmental external costs), we propose, as a second best solution, an excise tax harmonization model taking into consideration the specificity of each country and being, as far as possible, coherent with the environmental objective. This model proposes: the introduction of a minimum level of taxation on all products equal to the external cost due to the greenhouse effect (a common carbon tax); the possibility, given to the member states, of deviating from such minimum levels, in accordance with their specific requirements, internalizing in the price of the different products, by means of taxes additional to that CO2 minimum, the external costs associated with other pollutant agents (the same in all countries); the opportunity, in case it should be necessary to exceed the entire external cost, for the member states to apply increases that are in accordance with the environmental objective. Copyright © 2002 John Wiley & Sons, Ltd. and ERP Environment [source]


    Workers in the New Economy: Transformation as Border Crossing

    ETHOS, Issue 1 2006
    Valerie Walkerdine
    In this article, I seek to make an intervention in debates between psycho-logical and postmodern anthropology by engaging with the theme of border crossing. I argue that the theme of the border is one that fundamentally instantiates a separation between interior and exterior with respect to subjectivity, itself a funda-mental transformation and a painful and difficult border. This is related to a Cartesian distinction critiqued in this article. How the distinction between interior and exterior may be transcended is discussed in relation to examples of transformation from the crossing of class borders to the production and regulation of workers in a globalized and neoliberal economy. I begin with reference to postwar transformations of class with its anxious borders and go on to think about changes in the labor market and how these demand huge transformations that tear apart communities, destroy work-places, and sunder the sense of safety and stability that those gave. Advanced liberalism or neoliberalism brings with it a speeding up of the transformations of liberalism in which subjects are constantly invoked as self-contained, with a trans-portable self that must be produced through the developmental processes of personality and rationality. This self must be carried like a snail carries a shell. It must be coherent yet mutable, fixed yet multiple and flexible. But this view of the subject covers over the many connections that make subjectivity possible. I conclude by ask-ing what it would mean to rethink this issue of the production of safe spaces beyond an essentialist psychological conception of only one mother child space, separated from the social world, as having the power to produce feelings of safety? I end the article with an argument for a relational approach to subjectivity and sociality. [subjectivity, relationality, neoliberalism, workers, class] [source]


    Molecular evidence-based medicine

    EUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 5 2007
    Evolution, integration of information in the genomic era
    Abstract Evidence-based medicine and molecular medicine have both been influential in biomedical research in the last 15 years. Despite following largely parallel routes to date, the goals and principles of evidence-based and molecular medicine are complementary and they should be converging. I define molecular evidence-based medicine as the study of medical information that makes sense of the advances of molecular biological disciplines and where errors and biases are properly appreciated and placed in context. Biomedical measurement capacity improves very rapidly. The exponentially growing mass of hypotheses being tested requires a new approach to both statistical and biological inference. Multidimensional biology requires careful exact replication of research findings, but indirect corroboration is often all that is achieved at best. Besides random error, bias remains a major threat. It is often difficult to separate bias from the spirit of scientific inquiry to force data into coherent and ,significant' biological stories. Transparency and public availability of protocols, data, analyses and results may be crucial to make sense of the complex biology of human disease and avoid being flooded by spurious research findings. Research efforts should be integrated across teams in an open, sharing environment. Most research in the future may be designed, performed, and integrated in the public cyberspace. [source]


    PRECLINICAL STUDY: FULL ARTICLE: Altered architecture and functional consequences of the mesolimbic dopamine system in cannabis dependence

    ADDICTION BIOLOGY, Issue 3 2010
    Saturnino Spiga
    ABSTRACT Cannabinoid withdrawal produces a hypofunction of mesencephalic dopamine neurons that impinge upon medium spiny neurons (MSN) of the forebrain. After chronic treatment with two structurally different cannabinoid agonists, ,9 -tetrahydrocannabinol and CP55 940 (CP) rats were withdrawn spontaneously and pharmacologically with the CB1 antagonist SR141716A (SR). In these two conditions, evaluation of tyrosine hydroxylase (TH)-positive neurons revealed significant morphometrical reductions in the ventrotegmental area but not substantia nigra pars compacta of withdrawn rats. Similarly, confocal analysis of Golgi,Cox-stained sections of the nucleus accumbens revealed a decrease in the shell, but not the core, of the spines' density of withdrawn rats. Administration of the CB1 antagonist SR to control rats, provoked structural abnormalities reminiscent of those observed in withdrawal conditions and support the regulatory role of cannabinoids in neurogenesis, axonal growth and synaptogenesis by acting as eu-proliferative signals through the CB1 receptors. Further, these measures were incorporated into a realistic computational model that predicts a strong reduction in the excitability of morphologically altered MSN, yielding a significant reduction in action potential output. These pieces of evidence support the tenet that withdrawal from addictive compounds alters functioning of the mesolimbic system and provide direct morphological evidence for functional abnormalities associated with cannabinoid dependence at the level of dopaminergic neurons and their postsynaptic counterpart and are coherent with recent hypothesis underscoring a hypodopaminergic state as a distinctive feature of the ,addicted brain'. [source]


    High-frequency gamma oscillations coexist with low-frequency gamma oscillations in the rat visual cortex in vitro

    EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 8 2010
    Olaleke O. Oke
    Abstract Synchronization of neuronal activity in the visual cortex at low (30,70 Hz) and high gamma band frequencies (> 70 Hz) has been associated with distinct visual processes, but mechanisms underlying high-frequency gamma oscillations remain unknown. In rat visual cortex slices, kainate and carbachol induce high-frequency gamma oscillations (fast-,; peak frequency , 80 Hz at 37°C) that can coexist with low-frequency gamma oscillations (slow-,; peak frequency , 50 Hz at 37°C) in the same column. Current-source density analysis showed that fast-, was associated with rhythmic current sink-source sequences in layer III and slow-, with rhythmic current sink-source sequences in layer V. Fast-, and slow-, were not phase-locked. Slow-, power fluctuations were unrelated to fast-, power fluctuations, but were modulated by the phase of theta (3,8 Hz) oscillations generated in the deep layers. Fast-, was spatially less coherent than slow-,. Fast-, and slow-, were dependent on ,-aminobutyric acid (GABA)A receptors, ,-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors and gap-junctions, their frequencies were reduced by thiopental and were weakly dependent on cycle amplitude. Fast-, and slow-, power were differentially modulated by thiopental and adenosine A1 receptor blockade, and their frequencies were differentially modulated by N -methyl- d -aspartate (NMDA) receptors, GluK1 subunit-containing receptors and persistent sodium currents. Our data indicate that fast-, and slow-, both depend on and are paced by recurrent inhibition, but have distinct pharmacological modulation profiles. The independent co-existence of fast-, and slow-, allows parallel processing of distinct aspects of vision and visual perception. The visual cortex slice provides a novel in vitro model to study cortical high-frequency gamma oscillations. [source]


    The mouse VPAC2 receptor confers suprachiasmatic nuclei cellular rhythmicity and responsiveness to vasoactive intestinal polypeptide in vitro

    EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2003
    David J. Cutler
    Abstract Expression of coherent and rhythmic circadian (, 24 h) variation of behaviour, metabolism and other physiological processes in mammals is governed by a dominant biological clock located in the hypothalamic suprachiasmatic nuclei (SCN). Photic entrainment of the SCN circadian clock is mediated, in part, by vasoactive intestinal polypeptide (VIP) acting through the VPAC2 receptor. Here we used mice lacking the VPAC2 receptor (Vipr2,/,) to examine the contribution of this receptor to the electrophysiological actions of VIP on SCN neurons, and to the generation of SCN electrical firing rate rhythms SCN in vitro. Compared with wild-type controls, fewer SCN cells from Vipr2,/, mice responded to VIP and the VPAC2 receptor-selective agonist Ro 25-1553. By contrast, similar proportions of Vipr2,/, and wild-type SCN cells responded to gastrin-releasing peptide, arginine vasopressin or N -methyl- d -aspartate. Moreover, VIP-evoked responses from control SCN neurons were attenuated by the selective VPAC2 receptor antagonist PG 99-465. In firing rate rhythm experiments, the midday peak in activity observed in control SCN cells was lost in Vipr2,/, mice. The loss of electrical activity rhythm in Vipr2,/, mice was mimicked in control SCN slices by chronic treatment with PG 99-465. These results demonstrate that the VPAC2 receptor is necessary for the major part of the electrophysiological actions of VIP on SCN cells in vitro, and is of fundamental importance for the rhythmic and coherent expression of circadian rhythms governed by the SCN clock. These findings suggest a novel role of VPAC2 receptor signalling, and of cell-to-cell communication in general, in the maintenance of core clock function in mammals, impacting on the cellular physiology of SCN neurons. [source]


    Strain differences in ,1 receptor-mediated behaviours are related to neurosteroid levels

    EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 9 2002
    Vân-Ly Phan
    Abstract The sigma1 (,1) receptor exerts a potent neuromodulatory role in the brain with relevant consequences in memory processes, response to stress, depression and pharmacodependence. Its precise endogenous ligand is not yet identified but the ,1 receptor appears to be one target for the nongenomic rapid effects of neuroactive steroids in the brain. The aim of the present study was to establish whether differences in ,1 receptor-mediated behaviours could be observed among mouse strains, in relation with differences in either ,1 receptor expression or steroid levels. The ,1 -receptor immunohistochemical distribution appeared similar between Swiss and C57BL/6 strains in all the brain structures examined. The levels of in vivo[3H](+)-SKF-10 047 binding to ,1 receptors were lower in Swiss than in C57BL/6. Adrenalectomy/castration significantly increased [3H](+)-SKF-10 047 binding only in Swiss. The behavioural efficacy of the selective ,1 agonists igmesine and PRE-084 , reversion of the scopolamine-induced amnesia in the passive avoidance test; diminution of the immobility duration in the forced swimming test , were significantly higher in C57BL/6 than in Swiss. Steroid levels were measured in the brain in basal conditions and after stress. C57BL/6 mice presented in both conditions, the lowest progesterone levels, this steroid acting as an endogenous ,1 antagonist. Collectively, the results suggested that strain differences in neuroactive steroid and particularly, progesterone, biosynthesis and sensitivity may contribute to the differential behavioural efficacy of ,1 -receptor ligands. Noteworthy, these observations are coherent with strain differences observed in the intensity of cocaine-induced reward properties, known to critically involve the ,1 receptor. [source]


    Discussion on ,Personality psychology as a truly behavioural science' by R. Michael Furr

    EUROPEAN JOURNAL OF PERSONALITY, Issue 5 2009
    Article first published online: 14 JUL 200
    Yes We Can! A Plea for Direct Behavioural Observation in Personality Research MITJA D. BACK and BORIS EGLOFF Department of Psychology, Johannes Gutenberg University Mainz, Germany mback@uni-leipzig.de Furr's target paper (this issue) is thought to enhance the standing of personality psychology as a truly behavioural science. We wholeheartedly agree with this goal. In our comment we argue for more specific and ambitious requirements for behavioural personality research. Specifically, we show why behaviour should be observed directly. Moreover, we illustratively describe potentially interesting approaches in behavioural personality research: lens model analyses, the observation of multiple behaviours in diverse experimentally created situations and the observation of behaviour in real life. Copyright © 2009 John Wiley & Sons, Ltd. The Categories of Behaviour Should be Clearly Defined PETER BORKENAU Department of Psychology, Martin-Luther University Halle-Wittenberg, Germany p.borkenau@psych.uni-halle.de The target paper is helpful by clarifying the terminology as well as the strengths and weaknesses of several approaches to collect behavioural data. Insufficiently considered, however, is the clarity of the categories being used for the coding of behaviour. Evidence is reported showing that interjudge agreement for retrospective and even concurrent codings of behaviour does not execeed interjudge agreement for personality traits if the categories being used for the coding of behaviour are not clearly defined. By contrast, if the behaviour to be registered is unambiguously defined, interjudge agreement may be almost perfect. Copyright © 2009 John Wiley & Sons, Ltd. Behaviour Functions in Personality Psychology PHILIP J. CORR Department of Psychology, Faculty of Social Sciences, University of East Anglia, Norwich, UK Philip.Corr@btopenworld.com Furr's target paper highlights the importance, yet under-representation, of behaviour in published articles in personality psychology. Whilst agreeing with most of his points, I remain unclear as to how behaviour (as specifically defined by Furr) relates to other forms of psychological data (e.g. cognitive task performance). In addition, it is not clear how the functions of behaviour are to be decided: different behaviours may serve the same function; and identical behaviours may serve different functions. To clarify these points, methodological and theoretical aspects of Furr's proposal would benefit from delineation. Copyright © 2009 John Wiley & Sons, Ltd. On the Difference Between Experience-Sampling Self-Reports and Other Self-Reports WILLIAM FLEESON Department of Psychology, Wake Forest University, Winston-Salem, NC, USA fleesonW@wfu.edu Furr's fair but evaluative consideration of the strengths and weaknesses of behavioural assessment methods is a great service to the field. As part of his consideration, Furr makes a subtle and sophisticated distinction between different self-report methods. It is easy to dismiss all self-reports as poor measures, because some are poor. In contrast, Furr points out that the immediacy of the self-reports of behaviour in experience-sampling make experience-sampling one of the three strongest methods for assessing behaviour. This comment supports his conclusion, by arguing that ESM greatly diminishes one the three major problems afflicting self-reports,lack of knowledge,and because direct observations also suffer from the other two major problems afflicting self-reports. Copyright © 2009 John Wiley & Sons, Ltd. What and Where is ,Behaviour' in Personality Psychology? LAURA A. KING and JASON TRENT Department of Psychology, University of Missouri, Columbia, USA kingla@missouri.edu Furr is to be lauded for presenting a coherent and persuasive case for the lack of behavioural data in personality psychology. While agreeing wholeheartedly that personality psychology could benefit from greater inclusion of behavioural variables, here we question two aspects of Furr's analysis, first his definition of behaviour and second, his evidence that behaviour is under-appreciated in personality psychology. Copyright © 2009 John Wiley & Sons, Ltd. Naturalistic Observation of Daily Behaviour in Personality Psychology MATTHIAS R. MEHL Department of Psychology, University of Arizona, Tucson, AZ, USA mehl@email.arizona.edu This comment highlights naturalistic observation as a specific method within Furr's (this issue) cluster direct behavioural observation and discusses the Electronically Activated Recorder (EAR) as a naturalistic observation sampling method that can be used in relatively large, nomothetic studies. Naturalistic observation with a method such as the EAR can inform researchers' understanding of personality in its relationship to daily behaviour in two important ways. It can help calibrate personality effects against act-frequencies of real-world behaviour and provide ecological, behavioural personality criteria that are independent of self-report. Copyright © 2009 John Wiley & Sons, Ltd. Measuring Behaviour D. S. MOSKOWITZ and JENNIFER J. RUSSELL Department of Psychology, McGill University, Montreal, Canada dsm@psych.mcgill.ca Furr (this issue) provides an illuminating comparison of the strengths and weaknesses of various methods for assessing behaviour. In the selection of a method for assessing behaviour, there should be a careful analysis of the definition of the behaviour and the purpose of assessment. This commentary clarifies and expands upon some points concerning the suitability of experience sampling measures, referred to as Intensive Repeated Measurements in Naturalistic Settings (IRM-NS). IRM-NS measures are particularly useful for constructing measures of differing levels of specificity or generality, for providing individual difference measures which can be associated with multiple layers of contextual variables, and for providing measures capable of reflecting variability and distributional features of behaviour. Copyright © 2009 John Wiley & Sons, Ltd. Behaviours, Non-Behaviours and Self-Reports SAMPO V. PAUNONEN Department of Psychology, University of Western Ontario, London, Canada paunonen@uwo.ca Furr's (this issue) thoughtful analysis of the contemporary body of research in personality psychology has led him to two conclusions: our science does not do enough to study real, observable behaviours; and, when it does, too often it relies on ,weak' methods based on retrospective self-reports of behaviour. In reply, I note that many researchers are interested in going beyond the study of individual behaviours to the behaviour trends embodied in personality traits; and the self-report of behaviour, using well-validated personality questionnaires, is often the best measurement option. Copyright © 2009 John Wiley & Sons, Ltd. An Ethological Perspective on How to Define and Study Behaviour LARS PENKE Department of Psychology, The University of Edinburgh, Edinburgh, UK lars.penke@ed.ac.uk While Furr (this issue) makes many important contributions to the study of behaviour, his definition of behaviour is somewhat questionable and also lacks a broader theoretical frame. I provide some historical and theoretical background on the study of behaviour in psychology and biology, from which I conclude that a general definition of behaviour might be out of reach. However, psychological research can gain from adding a functional perspective on behaviour in the tradition of Tinbergens's four questions, which takes long-term outcomes and fitness consequences of behaviours into account. Copyright © 2009 John Wiley & Sons, Ltd. What is a Behaviour? MARCO PERUGINI Faculty of Psychology, University of Milan,Bicocca, Milan, Italy marco.perugini@unimib.it The target paper proposes an interesting framework to classify behaviour as well as a convincing plea to use it more often in personality research. However, besides some potential issues in the definition of what is a behaviour, the application of the proposed definition to specific cases is at times inconsistent. I argue that this is because Furr attempts to provide a theory-free definition yet he implicitly uses theoretical considerations when applying the definition to specific cases. Copyright © 2009 John Wiley & Sons, Ltd. Is Personality Really the Study of Behaviour? MICHAEL D. ROBINSON Department of Psychology, North Dakota State University, Fargo, ND, USA Michael.D.Robinson@ndsu.edu Furr (this issue) contends that behavioural studies of personality are particularly important, have been under-appreciated, and should be privileged in the future. The present commentary instead suggests that personality psychology has more value as an integrative science rather than one that narrowly pursues a behavioural agenda. Cognition, emotion, motivation, the self-concept and the structure of personality are important topics regardless of their possible links to behaviour. Indeed, the ultimate goal of personality psychology is to understanding individual difference functioning broadly considered rather than behaviour narrowly considered. Copyright © 2009 John Wiley & Sons, Ltd. Linking Personality and Behaviour Based on Theory MANFRED SCHMITT Department of Psychology, University of Koblenz-Landau, Landau, Germany schmittm@uni-landau.de My comments on Furr's (this issue) target paper ,Personality as a Truly Behavioural Science' are meant to complement his behavioural taxonomy and sharpen some of the presumptions and conclusions of his analysis. First, I argue that the relevance of behaviour for our field depends on how we define personality. Second, I propose that every taxonomy of behaviour should be grounded in theory. The quality of behavioural data does not only depend on the validity of the measures we use. It also depends on how well behavioural data reflect theoretical assumptions on the causal factors and mechanisms that shape behaviour. Third, I suggest that the quality of personality theories, personality research and behavioural data will profit from ideas about the psychological processes and mechanisms that link personality and behaviour. Copyright © 2009 John Wiley & Sons, Ltd. The Apparent Objectivity of Behaviour is Illusory RYNE A. SHERMAN, CHRISTOPHER S. NAVE and DAVID C. FUNDER Department of Psychology, University of California, Riverside, CA, USA funder@ucr.edu It is often presumed that objective measures of behaviour (e.g. counts of the number of smiles) are more scientific than more subjective measures of behaviour (e.g. ratings of the degree to which a person behaved in a cheerful manner). We contend that the apparent objectivity of any behavioural measure is illusory. First, the reliability of more subjective measures of behaviour is often strikingly similar to the reliabilities of so-called objective measures. Further, a growing body of literature suggests that subjective measures of behaviour provide more valid measures of psychological constructs of interest. Copyright © 2009 John Wiley & Sons, Ltd. Personality and Behaviour: A Neglected Opportunity? LIAD UZIEL and ROY F. BAUMEISTER Department of Psychology, Florida State University, Tallahassee, FL, USA Baumeister@psy.fsu.edu Personality psychology has neglected the study of behaviour. Furr's efforts to provide a stricter definition of behaviour will not solve the problem, although they may be helpful in other ways. His articulation of various research strategies for studying behaviour will be more helpful for enabling personality psychology to contribute important insights and principles about behaviour. The neglect of behaviour may have roots in how personality psychologists define the mission of their field, but expanding that mission to encompass behaviour would be a positive step. Copyright © 2009 John Wiley & Sons, Ltd. [source]


    Illusory and spurious correlations: distinct phenomena or joint outcomes of exemplar-based category learning?

    EUROPEAN JOURNAL OF SOCIAL PSYCHOLOGY, Issue 3 2006
    Thorsten Meiser
    Stereotype formation about novel groups was analyzed with trivariate stimulus distributions that were generated by group membership, valence of behavior, and a context variable. Within this stimulus setting, we manipulated the confounding role of the context variable and the distinctiveness of events in terms of their relative infrequency. The experimental procedure allowed us to analyze illusory and spurious correlations in a joint framework, to conduct focused tests for memory effects of relative infrequency and to investigate the detection of covariations with the context variable. The results revealed that illusory and spurious correlations were formed without enhanced memory for infrequent events and with existing covariations of the confounding context factor being well extracted. These observations suggest that illusory and spurious correlations can be understood without assuming specific cognitive processes that are tied to the particular characteristics of a given stimulus distribution, such as enhanced memory in the case of relative infrequency and neglect of a context variable in the case of a confounding factor. Instead, computer simulations with an exemplar-based learning model demonstrated that exemplar-based category learning may provide a coherent and integrative theoretical framework for illusory correlations, spurious correlations and true contingency learning in social cognition. Copyright © 2006 John Wiley & Sons, Ltd. [source]


    Temporal and spatial responses of British Columbia steelhead (Oncorhynchus mykiss) populations to ocean climate shifts

    FISHERIES OCEANOGRAPHY, Issue 1 2000
    Welch
    The pattern of temporal change in recruitment of steelhead trout (Oncorhynchus mykiss) entering the ocean between 1963 and 1990 was geographically coherent in all regions of British Columbia. A major increase in recruitment was evident for smolts entering the ocean after 1977. Subsequently, an out-of-phase response occurred after 1990, indicating that the effect of a possible 1990 regime shift had both temporal and geographical structure. Steelhead entering northern regions had increasing recruitment, while steelhead entering southern BC coastal regions had sharply decreasing recruitment. The evidence clearly indicates that the overall recruitment response since 1977 was primarily shaped by changes in marine (not freshwater) survival. Similar sudden changes in adult recruitment also appear to be occurring for other species of Pacific salmon in BC and Oregon, such as coho (O. kisutch), which appear to occur suddenly and show considerable persistence. A possible explanation for the change is that ocean productivity declined in coastal regions of southern BC after 1990, reducing the marine growth of juvenile salmon. The Bakun upwelling index shows a pattern of geographical coherence along the west coast of North America that could in principle explain the observed pattern of changes in recruitment. However, no evidence for a temporal shift in this index occurring around 1977 and 1990 is apparent. The reason for the sudden and persistent decline in ocean survival is therefore uncertain. [source]


    Temporal coherence of two alpine lake basins of the Colorado Front Range, U.S.A.

    FRESHWATER BIOLOGY, Issue 3 2000
    J. I. L. L. S. Baron
    1. Knowledge of synchrony in trends is important to determining regional responses of lakes to disturbances such as atmospheric deposition and climate change. We explored the temporal coherence of physical and chemical characteristics of two series of mostly alpine lakes in nearby basins of the Colorado Rocky Mountains. Using year-to-year variation over a 10-year period, we asked whether lakes more similar in exposure to the atmosphere be-haved more similarly than those with greater influence of catchment or in-lake processes. 2. The Green Lakes Valley and Loch Vale Watershed are steeply incised basins with strong altitudinal gradients. There are glaciers at the heads of each catchment. The eight lakes studied are small, shallow and typically ice-covered for more than half the year. Snowmelt is the dominant hydrological event each year, flushing about 70% of the annual discharge from each lake between April and mid-July. The lakes do not thermally stratify during the period of open water. Data from these lakes included surface water temper-ature, sulphate, nitrate, calcium, silica, bicarbonate alkalinity and conductivity. 3. Coherence was estimated by Pearson's correlation coefficient between lake pairs for each of the different variables. Despite close geographical proximity, there was not a strong direct signal from climatic or atmospheric conditions across all lakes in the study. Individual lake characteristics overwhelmed regional responses. Temporal coherence was higher for lakes within each basin than between basins and was highest for nearest neighbours. 4. Among the Green Lakes, conductivity, alkalinity and temperature were temporally coherent, suggesting that these lakes were sensitive to climate fluctuations. Water tem-perature is indicative of air temperature, and conductivity and alkalinity concentrations are indicative of dilution from the amount of precipitation flushed through by snowmelt. 5. In Loch Vale, calcium, conductivity, nitrate, sulphate and alkalinity were temporally coherent, while silica and temperature were not. This suggests that external influences are attenuated by internal catchment and lake processes in Loch Vale lakes. Calcium and sulphate are primarily weathering products, but sulphate derives both from deposition and from mineral weathering. Different proportions of snowmelt versus groundwater in different years could influence summer lake concentrations. Nitrate is elevated in lake waters from atmospheric deposition, but the internal dynamics of nitrate and silica may be controlled by lake food webs. Temperature is attenuated by inconsistently different climates across altitude and glacial meltwaters. 6. It appears that, while the lakes in the two basins are topographically close, geologically and morphologically similar, and often connected by streams, only some attributes are temporally coherent. Catchment and in-lake processes influenced temporal patterns, especially for temperature, alkalinity and silica. Montane lakes with high altitudinal gradients may be particularly prone to local controls compared to systems where coherence is more obvious. [source]


    Integration of lakes and streams in a landscape perspective: the importance of material processing on spatial patterns and temporal coherence

    FRESHWATER BIOLOGY, Issue 3 2000
    George W. Kling
    1. We studied the spatial and temporal patterns of change in a suite of twenty-one chemical and biological variables in a lake district in arctic Alaska, U.S.A. The study included fourteen stream sites and ten lake sites, nine of which were in a direct series of surface drainage. All twenty-four sites were sampled between one and five times a year from 1991 to 1997. 2. Stream sites tended to have higher values of major anions and cations than the lake sites, while the lake sites had higher values of particulate carbon, nitrogen, phosphorous and chlorophyll a. There were consistent and statistically significant differences in concentrations of variables measured at the inlet versus the outlet of lakes, and in variables measured at upstream versus downstream sites in the stream reaches which connect the lakes. In-lake processing tended to consume alkalinity, conductivity, H+, DIC, Ca2+, Mg2+, CO2, CH4, and NO3,, and produce K+ and dissolved organic carbon (DOC). In-stream processing resulted in the opposite trends (e.g. consumption of K+ and DOC), and the magnitudes of change were often similar to those measured in the lakes but with the opposite sign. 3. Observed spatial patterns in the study lakes included mean concentrations of variables which increased, decreased or were constant along the lake chain from high to low altitude in the catchment (stream sites showed no spatial patterns with any variables). The strongest spatial patterns were of increasing conductivity, Ca2+, Mg2+, alkalinity, dissolved inorganic carbon and pH with lake chain number (high to low altitude in the basin). These patterns were partly determined by the effect of increasing catchment area feeding into lakes further downslope, and partly by the systematic processing of materials in lakes and in the stream segments between lakes. 4. Synchrony (the temporal coherence or correlation of response) of variables across all lakes ranged from 0.18 for particulate phosphorus to 0.90 for Mg2+ the average synchrony for all twenty-one variables was 0.50. The synchronous behaviour of lake pairs was primarily related to the spatial location or proximity of the lakes for all variables taken together and for many individual variables, and secondarily, to the catchment to lake area ratio and the water residence time. 5. These results illustrate that, over small geographic areas, and somewhat independent of lake or stream morphometry, the consistent and directional (downslope) processing of materials helps produce spatial patterns which are coherent over time for many limnological variables. We combine concepts from stream, lake and landscape ecology, and develop a conceptual view of landscape mass balance. This view highlights that the integration of material processing in both lakes and rivers is critical for understanding the structure and function of surface waters, especially from a landscape perspective. [source]


    Geostatistical Prediction and Simulation of Point Values from Areal Data

    GEOGRAPHICAL ANALYSIS, Issue 2 2005
    Phaedon C. Kyriakidis
    The spatial prediction and simulation of point values from areal data are addressed within the general geostatistical framework of change of support (the term support referring to the domain informed by each measurement or unknown value). It is shown that the geostatistical framework (i) can explicitly and consistently account for the support differences between the available areal data and the sought-after point predictions, (ii) yields coherent (mass-preserving or pycnophylactic) predictions, and (iii) provides a measure of reliability (standard error) associated with each prediction. In the case of stochastic simulation, alternative point-support simulated realizations of a spatial attribute reproduce (i) a point-support histogram (Gaussian in this work), (ii) a point-support semivariogram model (possibly including anisotropic nested structures), and (iii) when upscaled, the available areal data. Such point-support-simulated realizations can be used in a Monte Carlo framework to assess the uncertainty in spatially distributed model outputs operating at a fine spatial resolution because of uncertain input parameters inferred from coarser spatial resolution data. Alternatively, such simulated realizations can be used in a model-based hypothesis-testing context to approximate the sampling distribution of, say, the correlation coefficient between two spatial data sets, when one is available at a point support and the other at an areal support. A case study using synthetic data illustrates the application of the proposed methodology in a remote sensing context, whereby areal data are available on a regular pixel support. It is demonstrated that point-support (sub-pixel scale) predictions and simulated realizations can be readily obtained, and that such predictions and realizations are consistent with the available information at the coarser (pixel-level) spatial resolution. [source]


    Duplex architecture and late-orogenic backthrusting in Foredeep Units of the Northern Apennines (Italy)

    GEOLOGICAL JOURNAL, Issue 4 2008
    Andrea Cerrina Feroni
    Abstract The Northern Apennines of Italy is a fold and thrust belt that resulted from the NE-ward progressive overthrusting of a Mesoalpine stacking (the ocean-derived Ligurian Units) onto the detached sedimentary cover of the Adria plate continental margin (Foredeep Units). The Futa Pass area represents a key sector for the reconstruction of the deformation history of two Foredeep Units (Acquerino and Carigiola Units). The tectonic evolution of this sector is characterized by the superposition of three main deformation stages, with a constant NNE,SSW compression direction. The oldest structure is represented by the NNE-verging Acquerino Unit duplex structure, the roof thrust of which is represented by the Ligurian stacking basal thrust. The interpretation of this structure as a large-scale duplex is supported by the presence in the outer sectors of the Northern Apennines belt of Ligurian Units directly overthrust on younger Foredeep Units. In the second deformation stage the NNE-verging Tavaiano Thrust developed. This regionally significant tectonic surface juxtaposes the Acquerino Unit (already developed as a duplex) and the overlying Ligurian Units, onto the Carigiola Unit. During this stage the fault pattern of the Carigiola Unit was also developed, characterized by two conjugate fault systems, coherent with a NNE,SSW maximum compression direction. During the last deformation stage, a backthrusting with a top-to-the SSW sense of movement (the Marcoiano Backthrust) brings the Carigiola Unit and its tectonic cover over the Acquerino and Ligurian Units, with the development of a large footwall syncline. The deformation history presented here differs from previous studies, and so provides a contribution to the debate on Northern Apennines tectonic evolution. Copyright © 2008 John Wiley & Sons, Ltd. [source]


    Tectonic deformation around the eastern Himalayan syntaxis: constraints from the Cretaceous palaeomagnetic data of the Shan-Thai Block

    GEOPHYSICAL JOURNAL INTERNATIONAL, Issue 2 2008
    Kenji Tanaka
    SUMMARY Lower to Middle Cretaceous red sandstones were sampled at four localities in the Lanpin-Simao fold belt of the Shan-Thai Block to describe its regional deformational features. Most of the samples revealed a characteristic remanent magnetization with unblocking temperatures around 680 °C. Primary natures of magnetization are ascertained through positive fold test. A tilt-corrected formation-mean direction for the Jingdong (24.5°N, 100.8°E) locality, which is located at a distance of 25 km from the Ailaoshan,Red River Fault, revealed northerly declination with steep inclination (Dec./Inc. = 8.3°/48.8°, ,95= 7.7°, N= 13). However, mean directions obtained from the Zhengyuan (24.0°N, 101.1°E), West Zhengyuan (24.0°N, 101.1°E) and South Mengla (21.4°N, 101.6°E) localities indicate an easterly deflection in declination; such as Dec./Inc. = 61.8°/46.1°, ,95= 8.1° (N= 7), Dec./Inc. = 324.2°/,49.4°, ,95= 6.4° (N= 4) and Dec./Inc. = 51.2°/46.4°, ,95= 5.6° (N= 13), respectively. The palaeomagnetic directions obtained from these four localities are incorporated into a palaeomagnetic database for the Shan-Thai Block. When combined with geological, geochronological and GPS data, the processes of deformation in the Shan-Thai Block is described as follows: Subsequent to its rigid block clockwise rotation of about 20° in the early stage of India,Asia collision, the Shan-Thai Block experienced a coherent but southward displacement along the Red River Fault prior to 32 Ma. This block was then subjected to a north,south compressive stresses during the 32,27 Ma period, which played a key role in shaping the structure of Chongshan-Lancang-Chiang Mai Belt. Following this some local clockwise rotational motion has occurred during the Pliocene-Quaternary time in central part of the Shan-Thai Block as a result of internal block movements along the reactivated network of faults. [source]


    Measuring finite-frequency body-wave amplitudes and traveltimes

    GEOPHYSICAL JOURNAL INTERNATIONAL, Issue 1 2006
    Karin Sigloch
    SUMMARY We have developed a method to measure finite-frequency amplitude and traveltime anomalies of teleseismic P waves. We use a matched filtering approach that models the first 25 s of a seismogram after the P arrival, which includes the depth phases pP and sP. Given a set of broad-band seismograms from a teleseismic event, we compute synthetic Green's functions using published moment tensor solutions. We jointly deconvolve global or regional sets of seismograms with their Green's functions to obtain the broad-band source time function. The matched filter of a seismogram is the convolution of the Green's function with the source time function. Traveltimes are computed by cross-correlating each seismogram with its matched filter. Amplitude anomalies are defined as the multiplicative factors that minimize the RMS misfit between matched filters and data. The procedure is implemented in an iterative fashion, which allows for joint inversion for the source time function, amplitudes, and a correction to the moment tensor. Cluster analysis is used to identify azimuthally distinct groups of seismograms when source effects with azimuthal dependence are prominent. We then invert for one source time function per group. We implement this inversion for a range of source depths to determine the most likely depth, as indicated by the overall RMS misfit, and by the non-negativity and compactness of the source time function. Finite-frequency measurements are obtained by filtering broad-band data and matched filters through a bank of passband filters. The method is validated on a set of 15 events of magnitude 5.8 to 6.9. Our focus is on the densely instrumented Western US. Quasi-duplet events (,quplets') are used to estimate measurement uncertainty on real data. Robust results are achieved for wave periods between 24 and 2 s. Traveltime dispersion is on the order of 0.5 s. Amplitude anomalies are on the order of 1 db in the lowest bands and 3 db in the highest bands, corresponding to amplification factors of 1.2 and 2.0, respectively. Measurement uncertainties for amplitudes and traveltimes depend mostly on station coverage, accuracy of the moment tensor estimate, and frequency band. We investigate the influence of those parameters in tests on synthetic data. Along the RISTRA array in the Western US, we observe amplitude and traveltime patterns that are coherent on scales of hundreds of kilometres. Below two sections of the array, we observe a combination of frequency-dependent amplitude and traveltime patterns that strongly suggest wavefront healing effects. [source]


    Similar Ends, Differing Means: Contractualism and Civil Service Reform in Denmark and New Zealand

    GOVERNANCE, Issue 1 2004
    Robert Gregory
    State sector reform was an integral component of the radical economic and social policy changes enacted by New Zealand governments between 1984 and 1991. This reform replaced the traditional tenured public service with a contractual regime. Through a comparison with Denmark, it is shown that New Zealand's reforms were not unique. Similar reforms were enacted in Denmark. But contrary to what occurred in New Zealand, the Danish reforms had already begun in the 1960s, and have since been gradually expanded. The parallel contractual regimes introduced in the two countries are accounted for by an increasing demand among politicians to secure a civil service that is responsive to political executive demands. However, because of institutional differences and diverging regulatory regimes, the strategic approaches in the two countries have been different. Whereas the New Zealand approach was dominated by an appeal to a coherent and sophisticated body of theoretical knowledge, combined with strict formalization, the Danish strategy has been based on political bargaining with the civil service unions. In both cases the reforms rest on critical assumptions regarding their positive and negative implications. [source]


    The Construction of Qualification Levels and Frameworks: Issues from Three UK Projects

    HIGHER EDUCATION QUARTERLY, Issue 4 2001
    Stan Lester
    The United Kingdom is gradually moving to develop national frameworks of qualifications, with the aim of identifying all publicly-funded qualifications according to level, focus and, where appropriate, size or credit volume. Existing frameworks designed for use in higher education and occupational contexts reflect assumptions concerning things such as the nature of knowledge, the academic or occupational context of the learner, and the nature of access and progression within education and training. These assumptions do not hold for the full spectrum of qualifications, and need to be challenged if a fully inclusive framework is to emerge that is coherent while supporting requisite variety. [source]