High Level Of Coherence Research Articles

Collective spin dynamics in magnetic nanomaterials

Magnetic nanomaterials are considered, forrned by magneitc nanomolecules with high spins. The problem of spin reversal in these materials is analysex, which is of interest for the possible use of such materials for quantum information processing and quantum cormputing. The fastest spin reversal can be achieved by coupling the spin sample to a resonant electric circuit and by an appropriate choice of the system parameters. A principal pont is to choose these parameters so that to organize coherent spin motion. Dynamics of collective motion is modelled by computer simulations, which confirm the high level of dynarinical coherence of molecular spins in the pricess of spin reversal.

Institutional Resource Regimes: Towards sustainability through the combination of property-rights theory and policy analysis

Although the concept of sustainable development is gaining increasing political acknowledgement, despite the implementation of environmental policies specifically intended to solve problems in this area, environmental degradation resulting from the recurrent problems associated with the over-exploitation of natural resources remains an important concern for most countries. How can this situation be explained? This article postulates that a combination of approaches from the political sciences (in particular policy analysis) and institutional economics would enable the identification of the most relevant regulatory dimensions which can explain the (un)sustainable uses of resources. Based on this starting point, it develops an innovative theoretical framework, i.e. that of the Institutional Resource Regime (IRR). The adopted approach facilitates the analysis of the regulatory measures and resource management practices associated with complex and competitive heterogeneous use situations from a perspective of sustainability. Indeed, the two dimensions of “extent” and “coherence” enable the definition and categorization of the IRR of a given resource. The extent of an IRR refers to the total number of goods and services in use that are actually regulated by the regime at a given time, while the coherence measures the degree of coordination of the various user-actors within the regime. One of the major contributions of the IRR framework is its ability to describe the different configurations of regimes, both theoretically and empirically, and to predict their effect on the sustainability of a resource based on the hypothesis that high levels of regime extent and coherence are necessary preconditions for sustainability. By doing this, the IRR framework also enables the analysis of the actual use rights to the goods and services provided by resources as the result of the political strategies of actors who mobilize different legal provisions, which stem either from formal property rights to resources or from policies that regulate the use and protection of these resources. Having developed the central research hypotheses and the empirical research procedure, we present the lessons drawn from the first campaign of field research which was mainly conducted in Switzerland from 1999. Based on the evidence from these initial findings, it is suggested that the scope of the IRR framework could be far broader than evidenced by its application in the case of Switzerland where it was initially developed.

Intimacy in adolescent friendship: The roles of attachment, coherence, and self-disclosure

This study examined attachment, coherence, and self-disclosure as predictors of intimacy in adolescent friendships as well as the extent to which coherence and disclosure mediate the relationship between attachment and intimacy. Gender and grade-level effects on intimacy development were also examined for one hundred ninety-six seventh, eighth and ninth grade students (116 boys and 80 girls). Attachment, coherence, and disclosure strongly predicted intimacy. Self-disclosure and coherence also interacted to influence intimacy where a tendency toward self-disclosure contributes to intimacy to a greater extent at low (when compared to high) levels of coherence. Structural Equation Modeling indicated that only coherence and self-disclosure had a direct effect on intimacy. Avoidant and anxious attachment had an indirect affect on intimacy, and were mediated by coherence and disclosure. Clinical implications of the results are discussed.

Attentional changes in pre-stimulus oscillatory activity within early visual cortex are predictive of human visual performance

Physiological and neuroimaging studies provide evidence to suggest that attentional mechanisms operating within the fronto-parietal network may exert top–down control on early visual areas, priming them for forthcoming sensory events. The believed consequence of such priming is enhanced task performance. Using the technique of magnetoencephalography (MEG), we investigated this possibility by examining whether attention-driven changes in cortical activity are correlated with performance on a line-orientation judgment task. We observed that, approximately 200 ms after a covert attentional shift towards the impending visual stimulus, the level of phase-resetting (transient neural coherence) within the calcarine significantly increased for 2–10 Hz activity. This was followed by a suppression of alpha activity (near 10 Hz) which persisted until the onset of the stimulus. The levels of phase-resetting, alpha suppression and subsequent behavioral performance varied between subjects in a systematic fashion. The magnitudes of phase-resetting and alpha-band power were negatively correlated, with high levels of coherence associated with high levels of performance. We propose that top–down attentional control mechanisms exert their initial effects within the calcarine through a phase-resetting within the 2–10 Hz band, which in turn triggers a suppression of alpha activity, priming early visual areas for incoming information and enhancing behavioral performance.

Application of Gene Shaving and Mixture Models to Cluster Microarray Gene Expression Data

Researchers are frequently faced with the analysis of microarray data of a relatively large number of genes using a small number of tissue samples. We examine the application of two statistical methods for clustering such microarray expression data: EMMIX-GENE and GeneClust. EMMIX-GENE is a mixture-model based clustering approach, designed primarily to cluster tissue samples on the basis of the genes. GeneClust is an implementation of the gene shaving methodology, motivated by research to identify distinct sets of genes for which variation in expression could be related to a biological property of the tissue samples. We illustrate the use of these two methods in the analysis of Affymetrix oligonucleotide arrays of well-known data sets from colon tissue samples with and without tumors, and of tumor tissue samples from patients with leukemia. Although the two approaches have been developed from different perspectives, the results demonstrate a clear correspondence between gene clusters produced by GeneClust and EMMIX-GENE for the colon tissue data. It is demonstrated, for the case of ribosomal proteins and smooth muscle genes in the colon data set, that both methods can classify genes into co-regulated families. It is further demonstrated that tissue types (tumor and normal) can be separated on the basis of subtle distributed patterns of genes. Application to the leukemia tissue data produces a division of tissues corresponding closely to the external classification, acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL), for both methods. In addition, we also identify genes specific for the subgroup of ALL-Tcell samples. Overall, we find that the gene shaving method produces gene clusters at great speed; allows variable cluster sizes and can incorporate partial or full supervision; and finds clusters of genes in which the gene expression varies greatly over the tissue samples while maintaining a high level of coherence between the gene expression profiles. The intent of the EMMIX-GENE method is to cluster the tissue samples. It performs a filtering step that results in a subset of relevant genes, followed by gene clustering, and then tissue clustering, and is favorable in its accuracy of ranking the clusters produced.

Assessment of the measurement tools of dysfunctional breathing

Introduction Prevalence of dysfunctional breathing (DB) has been claimed to range from 10% 5 to 90%. 1 Currently the clinical assessment of dysfunctional breathing is problematic and there is controversy about the role of hypocapnia and the proposed relationship between symptoms and signs of dysfunctional breathing with CO 2 levels. 3,4 Dysfunctional breathing is being implicated in many conditions commonly seen by osteopaths including fibromyalgia and chronic pain 2 and work related musculo-skeletal problems. 6 In this study we aimed to determine how measurement tools used to predict dysfunctional breathing reflect CO 2 levels and how they correlate with each other. Methods Breathing assessment was performed on 120 adults. Assessment include carbon dioxide measurement via capnometry, breath holding time according to the Buteyko Method protocol, a manual assessment of respiratory motion (MARM), Nijmegen Questionnaire, self-assessment of breathing questionnaire, and Heart Rate Variability coherence with respiration. Various anthropometrical, health outcome and emotional status evaluations were also performed. Results Preliminary results indicate that none of the measures of dysfunctional breathing correlate significantly with CO 2 levels. Claims that breath holding time could accurately predict PCO 2 were not supported. D.B. measures that did show a correlation with each other include respiratory motion balance as tested by MARM and ability to achieve high levels of coherence between respiration and heart rate variability. The self-evaluation of breathing questionnaire showed good correlation with the validated Nijmegen Questionnaire in scores for breathlessness, breathing restriction and breathing pattern disturbance. Conclusions Signs and symptoms of dysfunctional breathing appear to exist even when PCO 2 levels appear normal. Breathing may reflect the function of many systems of the body and a purely biochemical view of breathing dysfunction may be limited. For a complete picture of patients' breathing it is necessary to evaluate the biomechanical aspects of breathing pattern and symptom patterns in addition to the assessment of carbon dioxide.

Discovering Coherent Biclusters from Gene Expression Data Using Zero-Suppressed Binary Decision Diagrams

The biclustering method can be a very useful analysis tool when some genes have multiple functions and experimental conditions are diverse in gene expression measurement. This is because the biclustering approach, in contrast to the conventional clustering techniques, focuses on finding a subset of the genes and a subset of the experimental conditions that together exhibit coherent behavior. However, the biclustering problem is inherently intractable, and it is often computationally costly to find biclusters with high levels of coherence. In this work, we propose a novel biclustering algorithm that exploits the zero-suppressedbinary decision diagrams (ZBDDs) data structure to cope with the computational challenges. Our method can find all biclusters that satisfy specific input conditions, and it is scalable to practical gene expression data. We also present experimental results confirming the effectiveness of our approach.

Exploring group process

This study takes as a starting point the need for further observational research in identifying the phenomenon of cohesion in group psychotherapy. The purpose is to test the possibility that there are relevant observational technologies that, like the microscope, can reveal phenomena that cannot be perceived directly but that underpin events at the perceptual level. Two text analytical approaches will be applied to mutually support possible findings: conversation analysis as a qualitative tool and quantitative computer-assisted text analysis following the therapeutic cycles model (TCM). The text to be analyzed is a transcript of Session 9 of a psychodynamic psychotherapy group for seven women diagnosed with an eating disorder. Within the cycles there is higher category density, higher levels of coherence, and tying across turns. The TCM reliably can identify features of the therapeutic process that are of clinical interest.

Pressure–heat release measurements during start-up conditions in a pulse combustor

An experimental study focusing on the temporal evolution of the global OH heat release ( q′) and dynamic pressure ( p′) from ignition to limit cycle conditions in an aerovalved pulse combustor has been carried out. The motivation of the work was to investigate how the thermo-acoustic relationships evolve, as very little is understood regarding how pressure and heat release couplings develop prior to establishing limit cycle conditions. The start-up experiments demonstrated that the total start-up sequences occurred within 100 ms and can be subdivided into three regimes: (i) ignition and decay; (ii) instability growth; and (iii) onset of limit cycle operation. The main results showed that upon ignition the high amplitude impulse pressure wave corresponded to the natural frequency of the pulse combustor at ambient gas temperature and was verified by an acoustic model. The pressure field over the growth period exhibited two main trends, either steady amplitude growth or a short delay interval followed by steady amplitude growth to limit cycle conditions. Overall, no reproducibility in frequency or phase during the growth period was observed pointing to the influence of strong non-linear interactions. When operating under limit cycle conditions, the heat release and pressure oscillations were in phase, possessed high levels of coherence, and exhibited narrow band frequency response at the operating frequency and several harmonics.

Fragmented coherence: solid waste management in Colombo

Notwithstanding the increasingly fragmented organizational relationships within Colombo's urban governance system, the cooperative nature of stakeholder relationships lends a high level of coherence to the overall system. Since 1995, Colombo's solid waste management system has been characterized by the increased role of the private sector, community‐based organizations and NGOs. Whilst the increasingly fragmented nature of this system exhibits some deeply ingrained problems, there are also a number of positives associated with the increased role of civil society actors and, in particular, the informal sector. Reforming regulatory frameworks so as to integrate some of the social norms that are integral to the lives of the majority of urban residents will contribute to regulatory frameworks being considerably more enforceable than is currently the case. Such reform requires that institutional and regulatory frameworks need to be flexible enough to adapt to the changing social, political and economic context. In the Colombo case, effective cooperation between public sector and civil society stakeholders illustrates that adaptive institutional arrangements grounded in pragmatism are feasible. The challenge that arises is to translate these institutional arrangements into adaptive regulatory frameworks — something that would require a significant mind shift on the part of planners and urban managers.En dépit de relations structurelles de plus en plus fragmentées, la nature coopérative des liens entre les différents acteurs apporte une forte cohérence à l'ensemble du système de gouvernance urbaine de Colombo. Depuis 1995, la gestion des déchets y est caractérisée par le rôle croissant du secteur privé, de groupements locaux et d'ONG. Si la nature plus fragmentée de ce système révèle des problèmes profondément ancrés, un certain nombre d'aspects positifs s'associe au rôle plus présent des acteurs de la société civile, notamment du secteur informel. Réformer les cadres statutaires afin de pouvoir y intégrer certaines normes sociales dominantes dans la vie des citadins contribuera à ce que ces cadres soient beaucoup plus faciles à mettre en œuvre qu'actuellement. Cette réforme implique que les cadres institutionnels et statutaires soient suffisamment souples pour s'adapter aux contextes social, politique et économique évolutifs. Dans le cas de Colombo, une coopération efficace entre les parties prenantes du secteur public et de la société civile montre que des dispositifs institutionnels adaptatifs fondés sur le pragmatisme sont viables. Le défi à relever tient à la possibilité de traduire ces dispositifs institutionnels en cadres statutaires adaptatifs, ce qui exigerait un net changement de mentalités chez les responsables et aménageurs urbains.

An updated analysis of long‐term sea level change in New Zealand

The original analysis of long‐term sea level change in New Zealand is updated with a new and extended analysis. In this new analysis the original hourly sea level data have been re‐examined to remove obvious errors that were still present, new data covering the period 1989–2000 has been added, and the sea level record for Wellington extended by the inclusion of recently discovered data covering the years 1891–1893. These new results indicate that relative sea levels in New Zealand have been rising at an average rate of 1.6 mm/yr over the last 100 years ‐ a figure that is not only within the error bounds of the original determination, but when corrected for glacial‐isostatic effects has a high level of coherency with other regional and global sea level rise determinations. There continues to be no evidence of any acceleration in relative sea levels over the record period.

Visual evoked potentials elicited by coherently moving dots in dyslexic children

The magnocellular deficit theory is one of the prominent hypotheses in dyslexia research. However, recent studies have produced conflicting results. Ten dyslexic children and 12 controls were examined with visual evoked potentials elicited by random dot kinematogram. The experiment comprises two sequences, one with randomly moving dots (control condition) and a second sequence where a fraction of the dots were moved coherently at the left or right side (depending on the level of coherence, 10%, 20%, and 40% of the dots). Randomly moving dots elicited two components, a P100 and P200, which were not different between the groups. Coherently moving dots elicited a late positivity between 300 and 800 ms, which was significantly attenuated in dyslexic children. The area of this component becomes larger at a higher level of coherence. This study supports the hypothesis of an impairment of a specific magnocellular function in dyslexia.

Quantification of the factors that influence discharge correlation in model motor neurons.

The purpose of this study was to quantify the influence of intrinsic properties, active dendritic conductances, and background excitation and inhibition on measures of discharge correlation in the time and frequency domains with known levels and patterns of common synaptic input. The study involved a computer simulation of a population of neurons with a range of input resistances (0.54-3.7 MOmega) and surface areas (407,000-712,000 microm(2)). The neurons were simulated with no, moderate, or high levels of active dendritic conductances and were activated with either excitatory input only or excitatory and inhibitory inputs. The patterns of common input, either branched common input or common modulation, were tested with 0, 30, 60, and 90% common input. The results confirm previous findings of an exponential relation between the level of common input and indexes of synchronization; only when the common input comprised >/=60% of the total excitatory input was there a significant effect on discharge correlation. Synchronization was greatest in models that had passive dendrites. Active dendritic conductances caused the discharge rate of the neuron to saturate and decreased motor-unit synchronization. However, the addition of 10% background inhibitory input increased synchronization in these models. In contrast, common rhythmic modulation of inputs at 24 Hz usually decreased synchronization. Significant coherence at the modulated frequency occurred in the commonly modulated neurons when >/=60% of the inputs were modulated. Furthermore, active dendritic conductances decreased coherence. Branched common input caused high levels of coherence across a broad spectrum and when combined with active dendritic conductances caused significant frequency peaks in the 30- to 50-Hz band. In conclusion, the level of inhibitory input and active dendritic conductances interact with the amount of common input to determine time- and frequency-domain discharge correlation.

Studies of fluctuations in the high-temperature plasma of modern stellarators by the microwave scattering technique

Microwave scattering diagnostics are described that allow direct measurements of the turbulent processes in the high-temperature plasma of magnetic confinement systems. The first physical results are presented from fluctuation measurements carried out in 2000–2001 in three stellarators: L-2M (Institute of General Physics, Moscow), LHD (National Institute of Fusion Science, Toki), and TJ-II (CIEMAT, Madrid). Plasma density fluctuations in the axial (heating) regions of the L-2M and LHD stellarators were measured from microwave scattering at the fundamental harmonic of the heating gyrotron radiation. In the TJ-II stellarator, a separate 2-mm microwave source was used to produce a probing beam; the measurements were performed at the middle of the plasma radius. Characteristic features of fluctuations, common for all three devices, are revealed by the methods of statistical and spectral analysis. These features are the wide frequency Fourier and wavelet spectra, autocorrelation functions with slowly decreasing tails, and non-Gaussian probability distributions of the magnitudes and the increments in the magnitude of fluctuations. Observations showed the high level of coherence between turbulent fluctuations in the central region and at the edge of the L-2M plasma. The drift-dissipative instability and the instability driven by trapped electrons are examined as possible sources of turbulence in a high-temperature plasma.

Rod catch trends for early-running MSW salmon in Scottish rivers (1952–1997): divergence among stock components

Temporal and spatial variations in rod catches of Atlantic salmon for the months February-June were examined for evidence of coherence using data for seven Scottish rivers, from 1952-1997. High levels of coherence were detected among rivers and among months. Examination of the combined catches for all Scottish rivers showed that rod catch trends over years differed among months. Marked declining trends over years were evident for February, March and April. The trends weakened progressively throughout the monthly series and rod catches were more stable in May and June. The divergence among months of trends over years is principally a feature of the later part of the time series (since ca. 1990). Marine and estuary net catches were combined with rod catches to estimate abundance prior to all the homewater fisheries. This suggests that abundance has declined for all the months examined. The contraction of marine and estuary fisheries has resulted in proportionately greater escapement to rivers, reducing the response of rod catches to underlying trends in pre-fishery abundance. We suggest that variation among months of rod catch trends over years is attributable to variations in marine mortality rate. Variation among monthly trends may reflect spatial variation in marine mortality rates among sub-catchment populations. Environmental effects acting on freshwater populations of juveniles in a spatially variable manner may subsequently cause parallel variation in marine mortality rates. Alternatively, variations in marine mortality rate may be attributable to population-specific migrations through spatially variable marine environments.

Coherent electrical activity between vibrissa sensory areas of cerebellum and neocortex is enhanced during free whisking.

We tested if coherent signaling between the sensory vibrissa areas of cerebellum and neocortex in rats was enhanced as they whisked in air. Whisking was accompanied by 5- to 15-Hz oscillations in the mystatial electromyogram, a measure of vibrissa position, and by 5- to 20-Hz oscillations in the differentially recorded local field potential (nablaLFP) within the vibrissa area of cerebellum and within the nablaLFP of primary sensory cortex. We observed that only 10% of the activity in either cerebellum or sensory neocortex was significantly phase-locked to rhythmic motion of the vibrissae; the extent of this modulation is in agreement with the results from previous single-unit measurements in sensory neocortex. In addition, we found that 40% of the activity in the vibrissa areas of cerebellum and neocortex was significantly coherent during periods of whisking. The relatively high level of coherence between these two brain areas, in comparison with their relatively low coherence with whisking per se, implies that the vibrissa areas of cerebellum and neocortex communicate in a manner that is incommensurate with whisking. To the extent that the vibrissa areas of cerebellum and neocortex communicate over the same frequency band as that used by whisking, these areas must multiplex electrical activity that is internal to the brain with activity that is that phase-locked to vibrissa sensory input.

Calculation of Average, Uncertainty Range, and Reliability of Regional Climate Changes from AOGCM Simulations via the “Reliability Ensemble Averaging” (REA) Method

The ‘‘reliability ensemble averaging’’ (REA) method for calculating average, uncertainty range, and a measure of reliability of simulated climate changes at the subcontinental scale from ensembles of different atmosphere‐ ocean general circulation model (AOGCM) simulations is introduced. The method takes into account two ‘‘reliability criteria’’: the performance of the model in reproducing present-day climate (‘‘model performance’’ criterion) and the convergence of the simulated changes across models (‘‘model convergence’’ criterion). The REA method is applied to mean seasonal temperature and precipitation changes for the late decades of the twenty-first century, over 22 land regions of the world, as simulated by a recent set of nine AOGCM experiments for two anthropogenic emission scenarios (the A2 and B2 scenarios of the Intergovernmental Panel for Climate Change). In the A2 scenario the REA average regional temperature changes vary between about 2 and 7 K across regions and they are all outside the estimated natural variability. The uncertainty range around the REA average change as measured by 6 the REA root-mean-square difference (rmsd) varies between 1 and 4 K across regions and the reliability is mostly between 0.2 and 0.8 (on a scale from 0 to 1). For precipitation, about half of the regional REA average changes, both positive and negative, are outside the estimated natural variability and they vary between about 225% and 130% (in units of percent of present-day precipitation). The uncertainty range around these changes (6 rmsd) varies mostly between about 10% and 30% and the corresponding reliability varies widely across regions. The simulated changes for the B2 scenario show a high level of coherency with those for the A2 scenario. Compared to simpler approaches, the REA method allows a reduction of the uncertainty range in the simulated changes by minimizing the influence of ‘‘outlier’’ or poorly performing models. The method also produces a quantitative measure of reliability that shows that both criteria need to be met by the simulations in order to increase the overall reliability of the simulated changes.

Interferometric characterization of spatial coherence of high energy synchrotron X-rays

A simple and direct interferometric technique for characterization of the source size and the transverse coherence length of synchrotron hard X-rays is discussed. A high level of spatial coherence of the X-ray beam allows us to detect the diffraction images (phase contrast patterns) of both the boron fiber of about 100 μm diameter and the slit of different widths. We characterize the level of coherence by comparison of the measured visibility of the interference fringes with the theoretical values by means of simple analytical formulas derived in this work. The analytical theory of both the fiber and the slit diffraction images is discussed in details. The results obtained analytically are confirmed by computer simulations. The proposed technique is well suited for third-generation synchrotron sources and was applied at the European Synchrotron Radiation Facility.

Determination of the drainage structure of a watershed using a digital elevation model and a digital river and lake network

Distributed hydrological models require a detailed definition of a watershed's internal drainage structure. The conventional approach to obtain this drainage structure is to use an eight flow direction matrix (D8) which is derived from a raster digital elevation model (DEM). However, this approach leads to a rather coarse drainage structure when monitoring or gauging stations need to be accurately located within a watershed. This is largely due to limitations of the D8 approach and the lack of information over flat areas and pits. The D8 approach alone is also unable to differentiate lakes from plain areas. To avoid these problems a new approach, using a digital river and lake network (DRLN) as input in addition to the DEM, has been developed. This new approach allows for an accurate fit between the DRLN and the modelled drainage structure, which is represented by a flow direction matrix and a modelled watercourse network. More importantly, the identification of lakes within the modelled network is now possible. The proposed approach, which is largely rooted in the D8 approach, uses the DRLN to correct modelled flow directions and network calculations. For DEM cells overlapped by the DRLN, flow directions are determined using DRLN connections only. The flow directions of the other DEM cells are evaluated with the D8 approach which uses a DEM that has been modified as a function of distance to the DRLN. The proposed approach has been tested on the Chaudière River watershed in southern Québec, Canada. The modelled watershed drainage structure showed a high level of coherence with the DRLN. A comparison between the results obtained with the D8 approach and those obtained by the proposed approach clearly demonstrated an improvement over the conventionally modelled drainage structure. The proposed approach will benefit hydrological models which require data such as a flow direction matrix, a river and lake network and sub-watersheds for drainage structure information.

Avaliação do sistema de informações hospitalares - SIH/SUS como fonte complementar na vigilância e monitoramento de doenças de notificação compulsória

The objective of this paper was to explore the potentialities of the Hospital Information System - SIH/SUS for epidemiologic surveillance and monitoring of Notifiable Diseases. The states and regions of Brazil constituted the study area. Data relative to hospital admittances for Notifiable Diseases, during the period from 1984 to 1998, was obtained from the SIH/SUS and data from the National Center of Epidemiology – CENEPI, during the period from 1980 to 1997. Data bases were linked by pathologies, hospital admittances and by place of occurrence - distributed for states and regions of the country. The results of the classification of the states according to the four larger absolute frequencies of admittances and reports and the comparison between the reports and the number of admittances according to the need of admittances for the pathologies, showed a high level of coherence between CENEPI and SIH data. It was concluded that SIH/SUS has a great agility in obtaining the data and shows a good capacity for monitoring the analyzed pathologies, being an important complementary source of information for surveillance of Notifiable Diseases.