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The use of unilateral force under George W. Bush is not a new phenomenon in US foreign policy. As the author argues, it is merely a continuation of Bill Clinton’s foreign policy and is deeply rooted in both the foreign policy traditions of Jacksonianism and Wilsonianism. The analysis concludes that Clinton used unilateralist foreign policy with a 'smile' whereas the Bush administration uses it with an attitude.
The article starts with an overview of modernization theories, its history of ups and downs as well as its present status. This first part is followed by an analysis of basic social structure distributions and trends in human development in selected countries. One major focal point of the paper is the Non-Western world and the Arab countries, in particular. The author looks at modernization and modernity in that region and comes to the conclusion that the Western world can no longer expect to be able to simply export its own values and its way of life to the rest of the world.
The paper presents a simulation and parameter-estimation approach for evaluating stochastic patterns of population growth and spread of an annual forest herb, Melampyrum pratense (Orobanchaceae). The survival of a species during large-scale changes in land use and climate will depend, to a considerable extent, on its dispersal and colonisation abilities. Predictions on species migration need a combination of field studies and modelling efforts. Our study on the ability of M. pratense to disperse into so far unoccupied areas was based on experiments in secondary woodland in NE Germany. Experiments started in 1997 at three sites where the species was not yet present, with 300 seeds sown within one square meter. Population development was then recorded until 2001 by mapping of individuals with a resolution of 5 cm. Additional observations considered density dependence of seed production. We designed a spatially explicit individual-based computer simulation model to explain the spatial patterns of population development and to predict future population spread. Besides primary drop of seeds (barochory) it assumed secondary seed transport by ants (myrmecochory) with an exponentially decreasing dispersal tail. An important feature of populationpattern explanation was the simultaneous estimation of both population-growth and dispersal parameters from consistent spatio-temporal data sets. As the simulation model produced stochastic time series and random spatially discrete distributions of individuals we estimated parameters by minimising the expectation of weighted sums of squares. These sums-ofsquares criteria considered population sizes, radial population distributions around the area of origin and distributions of individuals within squares of 25*25 cm, the range of density action. Optimal parameter values, together with the precision of the estimates, were obtained from calculating sums of squares in regular grids of parameter values. Our modelling results showed that transport of fractions of seeds by ants over distances of 1…2 m was indispensable for explaining the observed population spread that led to distances of at most 8 m from population origin within 3 years. Projections of population development over 4 additional years gave a diffusion-like increase of population area without any “outposts”. This prediction generated by the simulation model gave a hypothesis which should be revised by additional field observations. Some structural deviations between observations and model output already indicated that for full understanding of population spread the set of dispersal mechanisms assumed in the model may have to be extended by additional features of plant-animal mutualism.
The optical density of human macular pigment was measured for 50 observers ranging in age from 10 to 90 years. The psychophysical method required adjusting the radiance of a 1°, monochromatic light (400–550 nm) to minimize flicker (15 Hz) when presented in counterphase with a 460 nm standard. This test stimulus was presented superimposed on a broad-band, short-wave background. Macular pigment density was determined by comparing sensitivity under these conditions for the fovea, where macular pigment is maximal, and 5° temporally. This difference spectrum, measured for 12 observers, matched Wyszecki and Stiles's standard density spectrum for macular pigment. To study variation in macular pigment density for a larger group of observers, measurements were made at only selected spectral points (460, 500 and 550 nm). The mean optical density at 460 nm for the complete sample of 50 subjects was 0.39. Substantial individual differences in density were found (ca. 0.10–0.80), but this variation was not systematically related to age.
The spectral efficiency of blackness induction was measured in three normal trichromatic observers and in one deuteranomalous observer. The psychophysical task was to adjust the radiance of a monochromatic 60–120′ annulus until a 45′ central broadband field just turned black and its contour became indiscriminable from a dark surrounding gap that separated it from the annulus. The reciprocal of the radiance required to induce blackness with annulus wavelengths between 420 and 680 nm was used to define a spectral-efficiency function for the blackness component of the achromatic process. For each observer, the shape of this blackness-sensitivity function agreed with the spectral-efficiency function based on heterochromatic flicker photometry when measured with the same 60–120′ annulus. Both of these functions matched the Commission Internationale de l'Eclairage Vλ function except at short wavelengths. Ancillary measurements showed that the latter difference in sensitivity can be ascribed to nonuniformities of preretinal absorption, since the annular field excluded the central 60′ of the fovea. Thus our evidence indicates that, at least to a good first approximation, induced blackness is inversely related to the spectral-luminosity function. These findings are consistent with a model that separates the achromatic and the chromatic pathways.
The site of confluence of the artery and the portal vein in the liver still appears to be controversial. Anatomical studies suggested a presinusoidal or an intrasinusoidal confluence in the first, second or even final third of the sinusoids. The objective of this investigation was to study the problem with functional biochemical techniques. Rat livers were perfused through the hepatic artery and simultaneously either in the orthograde direction from the portal vein to the hepatic vein or in the retrograde direction from the hepatic vein to the portal vein. Arterial how was linearly dependent on arterial pressure between 70 cm H2O and 120 cm H2O at a constant portal or hepatovenous pressure of 18 cm H2O. An arterial pressure of 100 cm H2O was required for the maintenance of a homogeneous orthograde perfusion of the whole parenchyma and of a physiologic ratio of arterial to portal how of about 1:3. Glucagon was infused either through the artery or the portal vein and hepatic vein, respectively, to a submaximally effective ''calculated'' sinusoidal concentration after mixing of 0.1 nmol/L. During orthograde perfusions, arterial and portal glucagon caused the same increases in glucose output. Yet during retrograde perfusions, hepatovenous glucagon elicited metabolic alterations equal to those in orthograde perfusions, whereas arterial glucagon effected changes strongly reduced to between 10% and 50%. Arterially infused trypan blue was distributed homogeneously in the parenchyma during orthograde perfusions, whereas it reached clearly smaller areas of parenchyma during retrograde perfusions. Finally, arterially applied acridine orange was taken up by all periportal hepatocytes in the proximal half of the acinus during orthograde perfusions but only by a much smaller portion of periportal cells in the proximal third of the acinus during retrograde perfusions. These findings suggest that in rat liver, the hepatic artery and the portal vein mix before and within the first third of the sinusoids, rather than in the middle or even last third.
Content: Synopsis The Attitudes toward Rape Victims Scale: Psychometric Data from 14 Countries Scale Construction and Validation - Study One: Preliminary Analyses - Study Two: Test-Retest Reliability - Study Three: Construct Validity Cross-cultural Extensions - United States - United Kingdom - Germany - New Zealand - Canada - West Indies - Israel - Turkey - India - Hong Kong - Malaysia - Zimbabwe - Mexico - Metric Equivalence Discussion
The factors that determine the efficiency of energy transfer in aquatic food webs have been investigated for many decades. The plant-animal interface is the most variable and least predictable of all levels in the food web. In order to study determinants of food quality in a large lake and to test the recently proposed central importance of the long-chained eicosapentaenoic acid (EPA) at the pelagic producer-grazer interface, we tested the importance of polyunsaturated fatty acids (PUFAs) at the pelagic producerconsumer interface by correlating sestonic food parameters with somatic growth rates of a clone of Daphnia galeata. Daphnia growth rates were obtained from standardized laboratory experiments spanning one season with Daphnia feeding on natural seston from Lake Constance, a large pre-alpine lake. Somatic growth rates were fitted to sestonic parameters by using a saturation function. A moderate amount of variation was explained when the model included the elemental parameters carbon (r2 = 0.6) and nitrogen (r2 = 0.71). A tighter fit was obtained when sestonic phosphorus was incorporated (r2 = 0.86). The nonlinear regression with EPA was relatively weak (r2 = 0.77), whereas the highest degree of variance was explained by three C18-PUFAs. The best (r2 = 0.95), and only significant, correlation of Daphnia's growth was found with the C18-PUFA α-linolenic acid (α-LA; C18:3n-3). This correlation was weakest in late August when C:P values increased to 300, suggesting that mineral and PUFA-limitation of Daphnia's growth changed seasonally. Sestonic phosphorus and some PUFAs showed not only tight correlations with growth, but also with sestonic α-LA content. We computed Monte Carlo simulations to test whether the observed effects of α-LA on growth could be accounted for by EPA, phosphorus, or one of the two C18-PUFAs, stearidonic acid (C18:4n-3) and linoleic acid (C18:2n-6). With >99 % probability, the correlation of growth with α-LA could not be explained by any of these parameters. In order to test for EPA limitation of Daphnia's growth, in parallel with experiments on pure seston, growth was determined on seston supplemented with chemostat-grown, P-limited Stephanodiscus hantzschii, which is rich in EPA. Although supplementation increased the EPA content 80-800x, no significant changes in the nonlinear regression of the growth rates with α-LA were found, indicating that growth of Daphnia on pure seston was not EPA limited. This indicates that the two fatty acids, EPA and α-LA, were not mutually substitutable biochemical resources and points to different physiological functions of these two PUFAs. These results support the PUFA-limitation hypothesis for sestonic C:P < 300 but are contrary to the hypothesis of a general importance of EPA, since no evidence for EPA limitation was found. It is suggested that the resource ratios of EPA and α-LA rather than the absolute concentrations determine which of the two resources is limiting growth.
Significant seasonal variation in size at settlement has been observed in newly settled larvae of Dreissena polymorpha in Lake Constance. Diet quality, which varies temporally and spatially in freshwater habitats, has been suggested as a significant factor influencing life history and development of freshwater invertebrates. Accordingly, experiments were conducted with field-collected larvae to test the hypothesis that diet quality can determine planktonic larval growth rates, size at settlement and subsequent post-metamorphic growth rates. Larvae were fed one of two diets or starved. One diet was composed of cyanobacterial cells which are deficient in polyunsaturated fatty acids (PUFAs), and the other was a mixed diet rich in PUFAs. Freshly metamorphosed animals from the starvation treatment had a carbon content per individual 70% lower than that of larvae fed the mixed diet. This apparent exhaustion of larval internal reserves resulted in a 50% reduction of the postmetamorphic growth rates. Growth was also reduced in animals previously fed the cyanobacterial diet. Hence, low food quantity or low food quality during the larval stage of D. polymorpha lead to irreversible effects for postmetamorphic animals, and is related to inferior competitive abilities.
It has recently been demonstrated that the presentation of a rare target in a visual oddball paradigm induces a prolonged inhibition of microsaccades. In the field of electrophysiology, the amplitude of the P300 component in event-related potentials (ERP) has been shown to be sensitive to the stimulus category (target vs. non target) of the eliciting stimulus, its overall probability, and the preceding stimulus sequence. In the present study we further specify the functional underpinnings of the prolonged microsaccadic inhibition in the visual oddball task, showing that the stimulus category, the frequency of a stimulus and the preceding stimulus sequence influence microsaccade rate. Furthermore, by co-recording ERPs and eye-movements, we were able to demonstrate that, despite being largely sensitive to the same experimental manipulation, the amplitude of P300 and the microsaccadic inhibition predict each other very weakly, and thus constitute two independent measures of the brain’s response to rare targets in the visual oddball paradigm.
Narcissus and Echo
(2012)
George Eliot’s late novel Daniel Deronda tackles big, fundamental political questions that radiate from the societal circumstances of the novel’s production and reach deep into our present-day life. The novel critically analyses the capitalistic, morally flawed and standard-less English society and narrates the title hero’s proto-Zionist mission to found a Jewish nation that re-establishes history, meaning and ethical values. This study attempts to trace the novel’s two models of society and time by bringing them into resonance with the myth of Narcissus and Echo famously rendered by Ovid. The unloving, self-referential, visual Narcissus is read as the model for the capitalistic world of spectacle and speculation. Echo’s loving, memory-bearing voice forms an important part in the construction of the sublating unity of the Jewish nation-to-come. Guided by this resonance between George Eliot’s novel and Ovid’s myth pieces of critical theory and philosophy are woven into the study’s fabric. The resulting analysis dissects and deconstructs the novel’s fascinating and highly complex patterns of conditions of possibility for the fabrication of the redeeming Jewish nation, the very same conditions that the novel presents as the conditions of possibility for narrating a meaningful story.
The molecular packing and spatial correlations of two isomeric zwitterionic polymethacrylates and one polyacrylate analog are studied by means of X-ray analysis and conformational calculations. The analysis of the correlation functions and density distribution profiles suggest a double-layered molecular packing which is discussed for the three polymers investigated, with respect to their different chemical structures. Whereas the zwitterionic polymethacrylates studied exhibit liquid-like short-range order, the polyacrylate analog exhibits an ordered double-layered superstructure.
BACKGROUND: There is an increased need to replace materials derived from fossil sources by renewables. Sugar-cane derived carbohydrates are very abundant in Brazil and are the cheapest sugars available in the market, with more than 400 million tons of sugarcane processed in the year 2007. The objective of this work was to study the preparation of sugar acrylates from free sugars and free acrylic acid, thus avoiding the previous preparation of protected sugar derivatives, such as glycosides, or activated acrylates, such as vinyl acrylate. RESULTS: Lipase catalyzed esterification of three mono- and two disaccharides with acrylic acid, in the presence or absence of molecular sieves was investigated. The reactions were monitored by high-performance liquid chromatography (HPLC) and the products were analyzed by matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) mass spectrometry. The main products are mono- and diacrylates, while higher esters are formed as minor products. The highest conversion to sugar acrylates was observed for the D-glucose and D-fructose, followed by D-xylose and D-maltose. Molecular sieves had no pronounced effect on the conversion CONCLUSIONS: A feasible method is described to produce and to characterize sugar acrylates, including those containing more than two acrylate groups. The process for production of these higher esters could potentially be optimized further to produce molecules for cross-linking in acrylate polymerization and other applications. The direct enzymatic esterification of free carbohydrates with acrylic acid is unprecedented.
In this contribution, we provide a detailed dynamical analysis of the interfacial hydrogen migration mediated by scanning tunneling microscopy (STM). Contributions from the STM-current and from the non-adiabatic couplings are taken into account using only first principle models. The slight asymmetry of the tunnelling rates with respect to the potential bias sign inferred from experimental observations is reproduced by weighting the contributions of the metal acceptor–donor states for the propagation of the impinging electrons. The quasi-thermal inelastic collision mechanism is treated perturbatively. The influence of hydrogen pre-coverage is also investigated using new potential energy surfaces obtained from periodic density functional theory calculations. Fully quantum dynamical simulations of the system evolution are performed by solving the Pauli master equation, providing insight into the reaction mechanism of STM manipulation of subsurface hydrogens. It is observed that the hydrogen impurity favors resurfacing over occupation of the bulk and subsurface sites whenever possible. The present simulations give strong indication that the experimentally observed protuberances after STM-excitation are due to hydrogen accumulating in the vicinity of the surface.
We investigated the role of training-induced knowledge Schemas and encoding time on adult age differences in recall. High-plausible (schema coherent) words were recalled better than lowplausible (schema discrepant) words in both age groups. This difference was larger for old-adults than for young adults for presentation times ranging from 3 s to 11 s per word. After equating participants in overall recall (i.e., at 50% correct) by dynamic adjustment of presentation time, old adults again showed a stronger plausibility effect than young adults when recall was above criterion. In a second experiment with self-paced encoding, old adults used more time than young adults only for low-plausible pairs, yet they still remembered fewer of them. In a third experiment, both age groups preferred to imagine high- rather than low-plausible words, but this effect was more pronounced in old adults. The results indicate that, compared with young adults, old adults find it particularly difficult to form elaborative mental images of schema-discrepant information under a wide variety of time constraints during encoding. Results are discussed in relation to explanations based on age-related mental slowing.
In this paper we present an approach to recover the dynamics from recurrences of a system and then generate (multivariate) twin surrogate (TS) trajectories. In contrast to other approaches, such as the linear-like surrogates, this technique produces surrogates which correspond to an independent copy of the underlying system, i. e. they induce a trajectory of the underlying system visiting the attractor in a different way. We show that these surrogates are well suited to test for complex synchronization, which makes it possible to systematically assess the reliability of synchronization analyses. We then apply the TS to study binocular fixational movements and find strong indications that the fixational movements of the left and right eye are phase synchronized. This result indicates that there might be one centre only in the brain that produces the fixational movements in both eyes or a close link between two centres.
We present an approach to generate (multivariate) twin surrogates (TS) based on recurrence properties. This technique generates surrogates which correspond to an independent copy of the underlying system, i. e. they induce a trajectory of the underlying system starting at different initial conditions. We show that these surrogates are well suited to test for complex synchronisation and exemplify this for the paradigmatic system of R¨ossler oscillators. The proposed test enables to assess the statistical relevance of a synchronisation analysis from passive experiments which are typical in natural systems.
In June 2013, widespread flooding and consequent damage and losses occurred in Central Europe, especially in Germany. This paper explores what data are available to investigate the adverse impacts of the event, what kind of information can be retrieved from these data and how well data and information fulfil requirements that were recently proposed for disaster reporting on the European and international levels. In accordance with the European Floods Directive (2007/60/EC), impacts on human health, economic activities (and assets), cultural heritage and the environment are described on the national and sub-national scale. Information from governmental reports is complemented by communications on traffic disruptions and surveys of flood-affected residents and companies.
Overall, the impacts of the flood event in 2013 were manifold. The study reveals that flood-affected residents suffered from a large range of impacts, among which mental health and supply problems were perceived more seriously than financial losses. The most frequent damage type among affected companies was business interruption. This demonstrates that the current scientific focus on direct (financial) damage is insufficient to describe the overall impacts and severity of flood events.
The case further demonstrates that procedures and standards for impact data collection in Germany are widely missing. Present impact data in Germany are fragmentary, heterogeneous, incomplete and difficult to access. In order to fulfil, for example, the monitoring and reporting requirements of the Sendai Framework for Disaster Risk Reduction 2015–2030 that was adopted in March 2015 in Sendai, Japan, more efforts on impact data collection are needed.
Islamic movements in Iran
(2004)
The modernist Islamic Movement sought to reconcile modern values and Islamic faith and attempted to express these values through an Islamic discourse and to reform political, religious and educational institutions along modernist lines. However, such a movement in the Islamic Republic of Iran raised controversy among the traditional leadership and secular intellectual groups. The aim of this paper is to discuss how far modernist Islam could progress in an islamic republic with an old tradition.
The requirements of modern e-learning techniques change. Aspects such as community interaction, flexibility, pervasive learning and increasing mobility in communication habits become more important. To meet thesechallenges e-learning platforms must provide support on mobile learning. Most approaches try to adopt centralized and static elearning mechanisms to mobile devices. However, often technically it is not possible for all kinds of devices to be connected to a central server. Therefore we introduce an application of a mobile e-learning network which operates totally decentralized with the help of an underlying ad hoc network architecture. Furthermore the concept of ad hoc messaging network (AMNET) is used as basis system architecture for our approach to implement a platform for pervasive mobile elearning.
The requirements of modern e-learning techniques change. Aspects such as community interaction, flexibility, pervasive learning and increasing mobility in communication habits become more important. To meet these challenges e-learning platforms must provide support on mobile learning. Most approaches try to adopt centralised and static e-learning mechanisms to mobile devices. However, often technically it is not possible for all kinds of devices to be connected to a central server. Therefore we introduce an application of a mobile e-learning network which operates totally decentralised with the help of an underlying ad hoc network architecture. Furthermore the concept of ad hoc messaging network (AMNET) is used as basis system architecture for our approach to implement a platform for pervasive mobile e-learning.
To investigate the relationship between implicit psychological hypotheses and explicit empirical findings, summaries of twenty published studies on attitude-behaviour consistency were presented to a sample of forty-eight psychology undergraduates. Subjects were asked to estimate the percentage of agreement between attitudes and behaviour obtained by each study. Correlations between subjects' covariation judgements and empirically obtained attitude-behaviour consistencies were minimal and nonsignificant. Results are discussed in the light of more recent research on attitudebehaviour relationship.
This paper presents a new methodology for examining the phenomenon of subitizing. Subjects were presented with a standard numerosity-detection task but for a range of presentation times to allow Task-Accuracy Functions to be computed for individual subjects. The data appear to show a continuous change in processing for numerosities from 2 to 5 when the data are aggregated across subjects. At the level of individual subjects, there appear to be qualitative shifts in enumeration processing after 3 or 4 objects. The approach used in this experiment may be used to test the claim that subitizing is a distinct enumeration process that can be used for small numbers of objects.
My analysis of question-word questions in conversational question-answer sequences results in the decomposition of the conversational question into three systems of constitutive cues, which signal and contextualize the particular activity type in conversational interaction: (1) syntactic structure, (2) semantic relation to prior turn, and (3) prosody. These components are used and combined by interlocutors to distinguish between different activity types which (4) sequentially implicate different types of answers by the recipient in the next turn. Prosody is only one cooccurring cue, but in some cases it is the only distinctive one. It is shown that prosody, and in particular intonation, cannot be determined or even systematically related to syntactic sentence structure type or other sentence-grammatical principles, as most former and current theories of intonation postulate. Instead, prosody is an independent, autonomous signalling system, which is used as a contextualization device for the constitution of interactively relevant activity types in conversation.
This paper investigates speech styles and style-shifting in the speech of the moderator of a German radio participation programme. Style-shifting is shown to affect several distinct linguistic levels: phonetic, morphophonemic, syntactic, and lexical. The functions of style-shifting are related both to the discourse context and the broader institutional context. Relying on listeners' co-occurrence expectations with respect to language use in contexts and exploiting listeners' evaluations of processes of speech convergence and divergence, the moderator uses stereotypic markers at different style levels in locally strategic functions in discourse. On the one hand, thematic development is controlled by reinforcing obligations on the addressee. On the other hand, global social reciprocity patterns are constituted and secured. Patterns of reciprocity vary with different types of addressees. The conversational analysis of language variation shows that variation is not only a quantitative correlate of regional, social and contextual parameters as predominantly conceived of in sociolinguistics. Language variation is furthermore used as a means to signal social and interactive meaning in conversations.
Content: 1. Introduction 2. The notion of speech style: from a dependent variable to contextualization cue 3. Speech styles in conversation from a German Sozialamt 3.1 Extracts from conversation 3.2 Speech style constituting cues 3.3 Choice and alternation of speech styles in conversation 4. Summary and conclusions
A system of descriptive categories for the notation and analysis of intonation in natural conversation is presented and discussed in relation to other systems currently suggested for incorporation in discourse analysis, The categories are based on purely auditive criteria. They differ from e.g. tonetic approaches by relying more on transcribers' and analysts' perception of the form and internal cohesiveness of contours, especially with respect to rhythmicality and/or pitch contour (gestalt). Intonation is conceived of as a relational phenomenon; the role of intonation in conversational utterances can only be analyzed by considering its co-occurrence with other properties of utterances like syntactic, semantic and discourse organizational structures and devices. In general, intonation is viewed as one signalling system contributing to the contextualization of utterances in their conversational context. A broad functional differentiation between different types of intonation categories seems plausible: Local categories like accents might fulfill mainly semantic functions, while global categories like different contour types might fulfill primarily functions with respect to the interactive coordination of activities in conversation.
The role of intonation in the organization of repair and problem handling sequences in conversation
(1988)
Transcripts of repair and/or problem handling sequences from natural conversations are presented and analyzed with special reference to the role of intonation in the interactive organization of these sequences. It is shown that (a) in the initiation of so-called repair or local problem handling sequences, intonation is used as a type-distinctive device, and (b) in the handling of a global problem handling sequence, intonation is systematically used as a means to constitute and control participant cooperation. In general, intonation is analyzed as one contextualization cue cooccurring with specific syntactic, semantic and discourse organizational devices to signal the status of an utterance in conversational context. It is hypothesized that especially in the global problem handling sequence, different categories of intonation, i.e. different accent and contour types, are systematically used to signal and control participants' interactive problem handling in different, indexically relevant ways simultaneously.
After a review of previous work on the prosody of emotional involvement, data extracts from natural conversations are analyzed in order to argue for the constitution of an 'emphatic (speech) style', which linguistic devices are used to signal heightened emotive involvement. Participants use prosodic cues, in co-occurrence with syntactic and lexical cues, to contextualize turn-constructional units as 'emphatic'. Only realizations of prosodic categories that are marked in relation to surrounding uses of these categories have the power to contextualize units as displaying 'more-than-normal involvement'. In the appropriate context, and in cooccurrence with syntactic and lexical cues and sequential position, the context-sensitive interpretation of this involvement is 'emphasis'. Prosodic marking is used in addition to various unmarked cues that signal and constitute different activity types in conversation. Emphatic style highlights and reinforms particular conversational activities, and makes certain types of recipient responses locally relevant. In particular, switches from non-emphatic to emphatic style are used to contextualize 'peaks of involvement' or 'climaxes' in story-telling. These are shown in the paper to be 'staged' by speakers and treated by recipients as marked activities calling for displays of alignment with respect to the matter at hand. Signals of emphasis are deployable as techniques for locally organizing demonstrations of shared understanding and participant reciprocity in conversational interaction.
We present an approach to the correlated dynamics of many-electron systems. We show, that the twoelectron reduced density matrix (2RDM) can provide a suitable description of the real time evolution of a system. To achieve this, the hierarchy of equations of motion must be truncated in a practical way. Also, the computational effort, given that the 2RDM is represented by products of two-electron determinants, is discussed, and numerical model calculations are presented.
To determine whether Förster resonance energy transfer (FRET) measurements can provide quantitative distance information in single-molecule fluorescence experiments on polypeptides, we measured FRET efficiency distributions for donor and acceptor dyes attached to the ends of freely diffusing polyproline molecules of various lengths. The observed mean FRET efficiencies agree with those determined from ensemble lifetime measurements but differ considerably from the values expected from Förster theory, with polyproline treated as a rigid rod. At donor–acceptor distances much less than the Förster radius R0, the observed efficiencies are lower than predicted, whereas at distances comparable to and greater than R0, they are much higher. Two possible contributions to the former are incomplete orientational averaging during the donor lifetime and, because of the large size of the dyes, breakdown of the point-dipole approximation assumed in Förster theory. End-to-end distance distributions and correlation times obtained from Langevin molecular dynamics simulations suggest that the differences for the longer polyproline peptides can be explained by chain bending, which considerably shortens the donor–acceptor distances.
The salivary glands of the blowfly were injected with luminescent oxygen-sensitive microbeads. The changes in oxygen content within individual gland tubules during hormone-induced secretory activity were quantified. The measurements are based on an upgraded phase-modulation technique, where the phase shift of the sensor phosphorescence is determined independently from concentration and background signals. We show that the combination of a lock-in amplifier with a fluorescence microscope results in a convenient setup to measure oxygen concentrations within living animal tissues at the cellular level.
A technique has been developed to measure absolute intracellular oxygen concentrations in green plants. Oxygen-sensitive phosphorescent microbeads were injected into the cells and an optical multifrequency phase-modulation technique was used to discriminate the sensor signal from the strong autofluorescence of the plant tissue. The method was established using photosynthesis-competent cells of the giant algae Chara corallina L., and was validated by application to various cell types of other plant species.
Motivational conditions have been thus far largely neglected by contemporary theoretical approaches in knowledge psychology. The present article attempts to demonstrate the necessity for the greater integration of both. Suggestions are made regarding the choice and conceptualization of relevant motivational factors. Two possible groups of factors can be distinguished: (1) motivational factors of personality, and (2) motivational effects of action. Available theoretical approaches (e.g., the "levels of processing" approach) and examples are used to clarify the potential effects of these factors on the acquisition and representation of knowledge. Finally, a review is made of empirical studies allowing confirmatory allegations about the posited relationships between motivational factors and processes related to knowledge. This review reveals substantial research deficits on this topic.
Recent research related to the concept of interest is reviewed. It is argued that current constructs of motivation fail to include crucial aspects of the meaning of interest emphasized by classical American and German educational theorists. In contrast with many contemporary concepts (e.g., intrinsic learning orientation), interest is defined as a content-specific motivational characteristic composed of intrinsic feeling-related and value-related valences. Results from a number of studies are presented that indicate the importance of interest for the depth of text comprehension, the use of learning strategies, and the quality of the emotional experience while learning. The implications of these results and possible directions for future research are discussed.
The influence of topic interest, prior knowledge, and cognitive capabilities on text comprehension
(1990)
The present study investigated the influence of topic interest on the comprehension of texts. The primary goals of the study were as follows: (1) to formulate a new definition of the concept "topic interest", (2) to control for cognitive capabilities (intelligence, short-term memory) and prior knowledge, and(3) to assess different levels of comprehension. A total of 53 male students, majoring in computer science, took part in the study. Subjects were presented with a text on "Psychology of Emotion". Prior to reading the text, they were asked to indicate their level of interest in the topic. After reading the text, subjects were given a test of comprehension involving open-ended questions. The questions were designed to represent different levels of comprehension. The results show that the effect of topic interest on text comprehension is especially pronounced when a deeper level of understanding is required. Surprisingly, prior knowledge had no effect on the level of comprehension. Verbal intelligence, on the other hand, showed a clear effect on comprehension, especially in answering questions of simple knowledge. The effects of interest and verbal intelligence could be shown to be independent of one another.
Existing theoretical literature fails to explain satisfactorily the differences between the pay of workers that are covered by collective agreements and others who are not. This study aims at providing a model framework which is amenable for an analysis of this issue. Our general-equilibrium approach integrates a dual labor market and a two-sector product market. The results suggest that the so-called 'union wage gap' is largely determined by the degree of centralization of the bargains, and, to a somewhat lesser extent, by the expenditure share of the unionized sector's goods.
Dielectric spectroscopy is employed to analyze the molecular dynamics and the charge transport in mixtures of zwitterionic polymers of the type poly{3 [N(-methacryloyloxyalkyl)] N, [N-dimethylammonio propanesulfonate] with sodium iodide in the frequency range of 10²Hz-10(up)7 Hz and in the temperature range of 110 K-400 K. The amount of inorganic salt added varies from 0-200 mol-% relative to the number of zwitterionic groups present in the polymer, contributing strongly to the conductivity. One relaxation process is observed whose relaxation rate depends strongly on the length of the aliphatic spacer between the polymethacrylate main chain and the zwitterionic group. Exhibiting an Arrhenius-like temperature depence with activation energy EA = 47 KJ/mol, this relaxation process is assigned to fluctuation of the quaternary ammonium groups in the side chains. At higher temperatures, the dielectric properties and the conductivity are primarily dominated by the mobile inorganic ions: conductivity strongly depends on the salt concentration, showing a pronounced electrode polarization effect. The frequency and salt concentration, dependences of the conductivity can be quantitatively described as hopping of charge carriers being subject to spatially randomly varying energy barriers. For the low-frequency regime and for the critical frequency marking the onset of the conductivity's dispersion, the Barton-Nakajima-Namikawa (BNN) relationship is fulfilled.
When the eyes fixate at a point in a visual scene, small saccades rapidly shift the image on the retina. The effect of these microsaccades on the latency of subsequent large-scale saccades may be twofold. First, microsaccades are associated with an enhancement of visual perception. Their occurrence during saccade target perception should, thus, decrease saccade latencies. On the other hand, microsaccades likely indicate activity in fixation-related oculomotor neurons. These represent competitors to saccade-related cells in the interplay of gaze holding and shifting. Consequently, an increase in saccade latencies after microsaccades would be expected. Here, we present evidence for both aspects of microsaccadic impact on saccade latency. In a delayed response task, participants made saccades to visible or memorized targets. First, microsaccade occurrence up to 50 ms before target disappearance correlated with 18 ms (or 8%) faster saccades to memorized targets. Second, if microsaccades occurred shortly (i.e., < 150 ms) before a saccade was required, saccadic reaction times in visual and memory trials were increased by about 40 ms (or 16%). Hence, microsaccades can have opposite consequences for saccade latencies, pointing at a differential role of these fixational eye movements in preparation of motor programs.
Fixational eye movements occur involuntarily during visual fixation of stationary scenes. The fastest components of these miniature eye movements are microsaccades, which can be observed about once per second. Recent studies demonstrated that microsaccades are linked to covert shifts of visual attention [e.g., Engbert & Kliegl (2003), Vision Res 43:1035-1045]. Here,we generalized this finding in two ways. First, we used peripheral cues, rather than the centrally presented cues of earlier studies. Second, we spatially cued attention in vision and audition to visual and auditory targets. An analysis of microsaccade responses revealed an equivalent impact of visual and auditory cues on microsaccade-rate signature (i.e., an initial inhibition followed by an overshoot and a final return to the pre-cue baseline rate). With visual cues or visual targets,microsaccades were briefly aligned with cue direction and then opposite to cue direction during the overshoot epoch, probably as a result of an inhibition of an automatic saccade to the peripheral cue. With left auditory cues and auditory targets microsaccades oriented in cue direction. Thus, microsaccades can be used to study crossmodal integration of sensory information and to map the time course of saccade preparation during covert shifts of visual and auditory attention.
Following up on research suggesting an age-related reduction in the rightward extent of the perceptual span during reading (Rayner, Castelhano, & Yang, 2009), we compared old and young adults in an N+2-boundary paradigm in which a nonword preview of word N+2 or word N+2 itself is replaced by the target word once the eyes cross an invisible boundary located after word N. The intermediate word N+1 was always three letters long. Gaze durations on word N+2 were significantly shorter for identical than nonword N+2 preview both for young and for old adults with no significant difference in this preview benefit. Young adults, however, did modulate their gaze duration on word N more strongly than old adults in response to the difficulty of the parafoveal word N+1. Taken together, the results suggest a dissociation of preview benefit and parafoveal-on-foveal effect. Results are discussed in terms of age-related decline in resilience towards distributed processing while simultaneously preserving the ability to integrate parafoveal information into foveal processing. As such, the present results relate to proposals of regulatory compensation strategies older adults use to secure an overall reading speed very similar to that of young adults.
We consider the numerical treatment of Hamiltonian systems that contain a potential which grows large when the system deviates from the equilibrium value of the potential. Such systems arise, e.g., in molecular dynamics simulations and the spatial discretization of Hamiltonian partial differential equations. Since the presence of highly oscillatory terms in the solutions forces any explicit integrator to use very small step size, the numerical integration of such systems provides a challenging task. It has been suggested before to replace the strong potential by a holonomic constraint that forces the solutions to stay at the equilibrium value of the potential. This approach has, e.g., been successfully applied to the bond stretching in molecular dynamics simulations. In other cases, such as the bond-angle bending, this methods fails due to the introduced rigidity. Here we give a careful analysis of the analytical problem by means of a smoothing operator. This will lead us to the notion of the smoothed dynamics of a highly oscillatory Hamiltonian system. Based on our analysis, we suggest a new constrained formulation that maintains the flexibility of the system while at the same time suppressing the high-frequency components in the solutions and thus allowing for larger time steps. The new constrained formulation is Hamiltonian and can be discretized by the well-known SHAKE method.
Technical and physical systems, especially electronic circuits, are frequently modeled as a system of differential and nonlinear implicit equations. In the literature such systems of equations are called differentialalgebraic equations (DAEs). It turns out that the numerical and analytical properties of a DAE depend on an integer called the index of the problem. For example, the well-known BDF method of Gear can be applied, in general, to a DAE only if the index does not exceed one. In this paper we give a geometric interpretation of higherindex DAEs and indicate problems arising in connection with such DAEs by means of several examples.
The subject of this paper is the relation of differential-algebraic equations (DAEs) to vector fields on manifolds. For that reason, we introduce the notion of a regular DAE as a DAE to which a vector field uniquely corresponds. Furthermore, a technique is described which yields a family of manifolds for a given DAE. This socalled family of constraint manifolds allows in turn the formulation of sufficient conditions for the regularity of a DAE. and the definition of the index of a regular DAE. We also state a method for the reduction of higher-index DAEs to lowsr-index ones that can be solved without introducing additional constants of integration. Finally, the notion of realizability of a given vector field by a regular DAE is introduced, and it is shown that any vector field can be realized by a regular DAE. Throughout this paper the problem of path-tracing is discussed as an illustration of the mathematical phenomena.
In this paper, we show that symplectic partitioned Runge-Kutta methods conserve momentum maps corresponding to linear symmetry groups acting on the phase space of Hamiltonian differential equations by extended point transformation. We also generalize this result to constrained systems and show how this conservation property relates to the symplectic integration of Lie-Poisson systems on certain submanifolds of the general matrix group GL(n).
A theoretical famework for the investigation of the qualitative behavior of differential-algebraic equations (DAEs) near an equilibrium point is established. The key notion of our approach is the notion of regularity. A DAE is called regular locally around an equilibrium point if there is a unique vector field such that the solutions of the DAE and the vector field are in one-to-one correspondence in a neighborhood of this equili Drium point. Sufficient conditions for the regularity of an equilibrium point are stated. This in turn allows us to translate several local results, as formulated for vector fields, to DAEs that are regular locally around a g: ven equilibrium point (e.g. Local Stable and Unstable Manifold Theorem, Hopf theorem). It is important that ihese theorems are stated in terms of the given problem and not in terms of the corresponding vector field.