31 resultados para Binary and ternary correlations


Relevância:

100.00% 100.00%

Publicador:

Resumo:

The essential first step for a beginning reader is to learn to match printed forms to phonological representations. For a new word, this is an effortful process where each grapheme must be translated individually (serial decoding). The role of phonological awareness in developing a decoding strategy is well known. We examined whether beginner readers recruit different skills depending on the nature of the words being read (familiar words vs. nonwords). Print knowledge, phoneme and rhyme awareness, rapid automatized naming (RAN), phonological short term memory (STM), nonverbal reasoning, vocabulary, auditory skills and visual attention were measured in 392 pre-readers aged 4 to 5 years. Word and nonword reading were measured 9 months later. We used structural equation modeling to examine the skills-reading relationship and modeled correlations between our two reading outcomes and among all pre-reading skills. We found that a broad range of skills were associated with reading outcomes: early print knowledge, phonological STM, phoneme awareness and RAN. Whereas all these skills were directly predictive of nonword reading, early print knowledge was the only direct predictor of word reading. Our findings suggest that beginner readers draw most heavily on their existing print knowledge to read familiar words.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

We uncover high persistence in credit spread series that can obscure the relationship between the theoretical determinants of credit risk and observed credit spreads. We use a Markovswitching model, which also captures the stability (low frequency changes) of credit ratings, to show why credit spreads may continue to respond to past levels of credit risk, even though the state of the economy has changed. A bivariate model of credit spreads and either macroeconomic activity or equity market volatility detects large and significant correlations that are consistent with theory but have not been observed in previous studies. © 2010 Nova Science Publishers, Inc. All rights reserved.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Biomedical relation extraction aims to uncover high-quality relations from life science literature with high accuracy and efficiency. Early biomedical relation extraction tasks focused on capturing binary relations, such as protein-protein interactions, which are crucial for virtually every process in a living cell. Information about these interactions provides the foundations for new therapeutic approaches. In recent years, more interests have been shifted to the extraction of complex relations such as biomolecular events. While complex relations go beyond binary relations and involve more than two arguments, they might also take another relation as an argument. In the paper, we conduct a thorough survey on the research in biomedical relation extraction. We first present a general framework for biomedical relation extraction and then discuss the approaches proposed for binary and complex relation extraction with focus on the latter since it is a much more difficult task compared to binary relation extraction. Finally, we discuss challenges that we are facing with complex relation extraction and outline possible solutions and future directions.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

We use advanced statistical tools of time-series analysis to characterize the dynamical complexity of the transition to optical wave turbulence in a fiber laser. Ordinal analysis and the horizontal visibility graph applied to the experimentally measured laser output intensity reveal the presence of temporal correlations during the transition from the laminar to the turbulent lasing regimes. Both methods unveil coherent structures with well-defined time scales and strong correlations both, in the timing of the laser pulses and in their peak intensities. Our approach is generic and may be used in other complex systems that undergo similar transitions involving the generation of extreme fluctuations.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

In this work, the liquid-liquid and solid-liquid phase behaviour of ten aqueous pseudo-binary and three binary systems containing polyethylene glycol (PEG) 2050, polyethylene glycol 35000, aniline, N,N-dimethylaniline and water, in the temperature range 298.15-350.15 K and at ambient pressure of 0.1 MPa, was studied. The obtained temperature-composition phase diagrams showed that the only functional co-solvent was PEG2050 for aniline in water, while PEG35000 even showed a clear anti-solvent effect in the N,N-dimethylaniline aqueous system. The experimental solid-liquid equilibria (SLE) data have been correlated by the non-random two-liquid (NRTL) model, and the correlation results are in accordance with the experimental results.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The convergence on the Big Five in personality theory has produced a demand for efficient yet psychometrically sound measures. Therefore, five single-item measures, using bipolar response scales, were constructed to measure the Big Five and evaluated in terms of their convergent and off-diagonal divergent properties, their pattern of criterion correlations and their reliability when compared with four longer Big Five measures. In a combined sample (N?=?791) the Single-Item Measures of Personality (SIMP) demonstrated a mean convergence of r?=?0.61 with the longer scales. The SIMP also demonstrated acceptable reliability, self–other accuracy, and divergent correlations, and a closely similar pattern of criterion correlations when compared with the longer scales. It is concluded that the SIMP offer a reasonable alternative to longer scales, balancing the demands of brevity versus reliability and validity.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The density of the diffuse, primitive and classic beta-amyloid (Abeta) deposits and the incidence of large and small diameter blood vessels was studied in the upper laminae of the frontal cortex of 10 patients with sporadic Alzheimer’s disease (AD). The data were analysed using the partial correlation coefficient to determine whether variations in the density of Abeta deposit subtypes along the cortex were related to blood vessels. Significant correlations between the density of the diffuse or primitive Abeta deposits and blood vessels were found in only a small number of patients. However, the classic Abeta deposits were positively correlated with the large blood vessels in all 10 patients, the correlations remaining when the effects of gyral location and mutual correlations between Abeta deposits were removed. These results suggest that the larger blood vessels are involved specifically in the formation of the classic Abeta deposits and are less important in the formation of the diffuse and primitive deposits.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The literature relating to haze formation, methods of separation, coalescence mechanisms, and models by which droplets <100 μm are collected, coalesced and transferred, have been reviewed with particular reference to particulate bed coalescers. The separation of secondary oil-water dispersions was studied experimentally using packed beds of monosized glass ballotini particles. The variables investigated were superficial velocity, bed depth, particle size, and the phase ratio and drop size distribution of inlet secondary dispersion. A modified pump loop was used to generate secondary dispersions of toluene or Clairsol 350 in water with phase ratios between 0.5-6.0 v/v%.Inlet drop size distributions were determined using a Malvern Particle Size Analyser;effluent, coalesced droplets were sized by photography. Single phase flow pressure drop data were correlated by means of a Carman-Kozeny type equation. Correlations were obtained relating single and two phase pressure drops, as (ΔP2/μc)/ΔP1/μd) = kp Ua Lb dcc dpd Cine A flow equation was derived to correlate the two phase pressure drop data as, ΔP2/(ρcU2) = 8.64*107 [dc/D]-0.27 [L/D]0.71 [dp/D]-0.17 [NRe]1.5 [e1]-0.14 [Cin]0.26  In a comparison between functions to characterise the inlet drop size distributions a modification of the Weibull function provided the best fit of experimental data. The general mean drop diameter was correlated by: q_p q_p p_q /β      Γ ((q-3/β) +1) d qp = d fr  .α        Γ ((P-3/β +1 The measured and predicted mean inlet drop diameters agreed within ±15%. Secondary dispersion separation depends largely upon drop capture within a bed. A theoretical analysis of drop capture mechanisms in this work indicated that indirect interception and London-van der Waal's mechanisms predominate. Mathematical models of dispersed phase concentration m the bed were developed by considering drop motion to be analogous to molecular diffusion.The number of possible channels in a bed was predicted from a model in which the pores comprised randomly-interconnected passage-ways between adjacent packing elements and axial flow occured in cylinders on an equilateral triangular pitch. An expression was derived for length of service channels in a queuing system leading to the prediction of filter coefficients. The insight provided into the mechanisms of drop collection and travel, and the correlations of operating parameters, should assist design of industrial particulate bed coalescers.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This study is concerned with the linguistic situation in the town of Kirkuk in north eastern Iraq. In this town there are three main ethnic groups: Kurds, Arabs and Turkmana with some very smell minorities such as Chaldeene, Assyrians and Armenians. The languages spoken by these three ethnic groups belong to different language Family groups. In the First cart of the study the historical background of the population, a review of the literature, both of the present linguistic situation in Kirkuk end of relevant sociolinguistics in general, and the theoretical Framework, have been discussed in detail in order to provide background to this study which is mainly concerned with the Following areas: 1. The relationships existing between ethnic background and language usage and language loyalty in Kirkuk. 2. The attitudes of Kirkukiane towards language maintenance and language shift in Kirkuk. 3. Bilingual, multilingual individual communicative competence of Kurds, Arabs and Turkmans in the languages concerned, including the degree to which such a speaker is bilingual or multilingual and the nature of bilingualism or multilingualism in different domains and situations in Kirkuk. To throw light a these areas a situationally-oriented language survey was conducted; the relevant data was collected by randomly distributed questionnaire, by parsonal interview, by personal observation of language use and language attitudes in this town. The data subjected to commuter analysis and the results proved that the were no significant and substantial correlations between the language use, attitudes and competence based on the socio-economic status of respondents in this town, on the other hand, the correlations between the ethnic backgrounds and the language, use, attitudes and competence are indisoutable.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Origin of hydrodynamic turbulence in rotating shear flows is investigated. The particular emphasis is on flows whose angular velocities decrease but specific angular momenta increase with increasing radial coordinate. Such flows are Rayleigh stable, but must be turbulent in order to explain observed data. Such a mismatch between the linear theory and observations/experiments is more severe when any hydromagnetic/magnetohydrodynamic instability and the corresponding turbulence therein is ruled out. The present work explores the effect of stochastic noise on such hydrodynamic flows. We focus on a small section of such a flow which is essentially a plane shear flow supplemented by the Coriolis effect. This also mimics a small section of an astrophysical accretion disk. It is found that such stochastically driven flows exhibit large temporal and spatial correlations of perturbation velocities, and hence large energy dissipations, that presumably generate instability. A range of angular velocity profiles (for the steady flow), starting with the constant angular momentum to that of the constant circular velocity are explored. It is shown that the growth and roughness exponents calculated from the contour (envelope) of the perturbed flows are all identical, revealing a unique universality class for the stochastically forced hydrodynamics of rotating shear flows. This work, to the best of our knowledge, is the first attempt to understand origin of instability and turbulence in the three-dimensional Rayleigh stable rotating shear flows by introducing additive stochastic noise to the underlying linearized governing equations. This has important implications in resolving the turbulence problem in astrophysical hydrodynamic flows such as accretion disks.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The microbiological, physical and chemical changes which occur instored, harvested sugarcane were studied in Jamaica and the United Kingdom.The degree of deterioration was proportional to time of storage, and wasrevealed by a statistically significant reduction in sucrose content.Other symptoms included a fall in pH, and increases in reducing sugars,dextran, viscosity, and microbial count. Cut cane was universally infectedwith Leuconostoc mesenteroides, which reached a maximum count of 107 to 108organisms per ml. juice within. 3 to 4 days of harvest. Counts of othermicroorganisms were generally insignificant, except for occasional lactobacilli.A new dextran-forming species was named Lactobacillus confusus.Microorganisms isolated from deteriorated cane were screened for theirability to cause deterioration of a sterile, synthetic cane juice. L. mesenteroides strains were the most deteriogenic, but attempts toreproduce the symptoms of "sour" cane by inoculation of this organism intocut cane were only partially successful. L. mesenteroides was present in the soil and the epiphytic flora of the stalk. The principal vector of infection appeared to be the cutters' machete, especially in wet weather. Cane harvested by a chopper machine deteriorated more rapidly than hand-cut whole-stalks. Economic losses due to deterioration of harvested cane were estimated to be 9.2% of the initial recoverable sugar for the 1969 crop at Frome Estate, Jamaica. Dextran content was a useful indicator of cane biodeterioration. The dextran content of mill juices was correlated with rainfall, and significant correlations were obtained between dextran content and viscosity of mill syrups and the amount of sugar lost in final molasses; it also caused the formation of elongated crystals. Attempts to control sour cane by chemical and physical methods were unsuccessful, and it was concluded that the only solution is to mill cane within 24 hours of harvest. A novel method for removal of dextran from mill juices by enzymic treatment with dextranase was developed and patented.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Origin of hydrodynamic turbulence in rotating shear flows is investigated. The particular emphasis is on flows whose angular velocities decrease but specific angular momenta increase with increasing radial coordinate. Such flows are Rayleigh stable, but must be turbulent in order to explain observed data. Such a mismatch between the linear theory and observations/experiments is more severe when any hydromagnetic/magnetohydrodynamic instability and the corresponding turbulence therein is ruled out. The present work explores the effect of stochastic noise on such hydrodynamic flows. We focus on a small section of such a flow which is essentially a plane shear flow supplemented by the Coriolis effect. This also mimics a small section of an astrophysical accretion disk. It is found that such stochastically driven flows exhibit large temporal and spatial correlations of perturbation velocities, and hence large energy dissipations, that presumably generate instability. A range of angular velocity profiles (for the steady flow), starting with the constant angular momentum to that of the constant circular velocity are explored. It is shown that the growth and roughness exponents calculated from the contour (envelope) of the perturbed flows are all identical, revealing a unique universality class for the stochastically forced hydrodynamics of rotating shear flows. This work, to the best of our knowledge, is the first attempt to understand origin of instability and turbulence in the three-dimensional Rayleigh stable rotating shear flows by introducing additive stochastic noise to the underlying linearized governing equations. This has important implications in resolving the turbulence problem in astrophysical hydrodynamic flows such as accretion disks.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The origin of linear instability resulting in rotating sheared accretion flows has remained a controversial subject for a long time. While some explanations of such non-normal transient growth of disturbances in the Rayleigh stable limit were available for magnetized accretion flows, similar instabilities in the absence of magnetic perturbations remained unexplained. This dichotomy was resolved in two recent publications by Chattopadhyay and co-workers [Mukhopadhyay and Chattopadhyay, J. Phys. A 46, 035501 (2013)1751-811310.1088/1751-8113/46/3/035501; Nath, Phys. Rev. E 88, 013010 (2013)PLEEE81539-375510.1103/PhysRevE.88.013010] where it was shown that such instabilities, especially for nonmagnetized accretion flows, were introduced through interaction of the inherent stochastic noise in the system (even a "cold" accretion flow at 3000 K is too "hot" in the statistical parlance and is capable of inducing strong thermal modes) with the underlying Taylor-Couette flow profiles. Both studies, however, excluded the additional energy influx (or efflux) that could result from nonzero cross correlation of a noise perturbing the velocity flow, say, with the noise that is driving the vorticity flow (or equivalently the magnetic field and magnetic vorticity flow dynamics). Through the introduction of such a time symmetry violating effect, in this article we show that nonzero noise cross correlations essentially renormalize the strength of temporal correlations. Apart from an overall boost in the energy rate (both for spatial and temporal correlations, and hence in the ensemble averaged energy spectra), this results in mutual competition in growth rates of affected variables often resulting in suppression of oscillating Alfven waves at small times while leading to faster saturations at relatively longer time scales. The effects are seen to be more pronounced with magnetic field fluxes where the noise cross correlation magnifies the strength of the field concerned. Another remarkable feature noted specifically for the autocorrelation functions is the removal of energy degeneracy in the temporal profiles of fast growing non-normal modes leading to faster saturation with minimum oscillations. These results, including those presented in the previous two publications, now convincingly explain subcritical transition to turbulence in the linear limit for all possible situations that could now serve as the benchmark for nonlinear stability studies in Keplerian accretion disks.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

We investigate the evolution of magnetohydrodynamic (or hydromagnetic as coined by Chandrasekhar) perturbations in the presence of stochastic noise in rotating shear flows. The particular emphasis is the flows whose angular velocity decreases but specific angular momentum increases with increasing radial coordinate. Such flows, however, are Rayleigh stable but must be turbulent in order to explain astrophysical observed data and, hence, reveal a mismatch between the linear theory and observations and experiments. The mismatch seems to have been resolved, at least in certain regimes, in the presence of a weak magnetic field, revealing magnetorotational instability. The present work explores the effects of stochastic noise on such magnetohydrodynamic flows, in order to resolve the above mismatch generically for the hot flows. We essentially concentrate on a small section of such a flow which is nothing but a plane shear flow supplemented by the Coriolis effect, mimicking a small section of an astrophysical accretion disk around a compact object. It is found that such stochastically driven flows exhibit large temporal and spatial autocorrelations and cross-correlations of perturbation and, hence, large energy dissipations of perturbation, which generate instability. Interestingly, autocorrelations and cross-correlations appear independent of background angular velocity profiles, which are Rayleigh stable, indicating their universality. This work initiates our attempt to understand the evolution of three-dimensional hydromagnetic perturbations in rotating shear flows in the presence of stochastic noise. © 2013 American Physical Society.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Background: Food allergy is often a life-long condition that requires constant vigilance in order to prevent accidental exposure and avoid potentially life-threatening symptoms. Parents’ confidence in managing their child’s food allergy may relate to the poor quality of life anxiety and worry reported by parents of food allergic children. Objective: The aim of the current study was to develop and validate the first scale to measure parental confidence (self-efficacy) in managing food allergy in their child. Methods: The Food Allergy Self-Efficacy Scale for Parents (FASE-P) was developed through interviews with 53 parents, consultation of the literature and experts in the area. The FASE-P was then completed by 434 parents of food allergic children from a general population sample in addition to the General Self-Efficacy Scale (GSES), the Food Allergy Quality of Life Parental Burden Scale (FAQL-PB), the General Health Questionnaire (GHQ12) and the Food Allergy Impact Measure (FAIM). A total of 250 parents completed the re-test of the FASE-P. Results: Factor and reliability analysis resulted in a 21 item scale with 5 sub-scales. The overall scale and sub-scales has good to excellent internal consistency (α’s of 0.63-0.89) and the scale is stable over time. There were low to moderate significant correlations with the GSES, FAIM and GHQ12 and strong correlations with the FAQL-PB, with better parental confidence relating to better general self-efficacy, better quality of life and better mental health in the parent. Poorer self-efficacy was related to egg and milk allergy; self-efficacy was not related to severity of allergy. Conclusions and clinical relevance: The FASE-P is a reliable and valid scale for use with parents from a general population. Its application within clinical settings could aid provision of advice and improve targeted interventions by identifying areas where parents have less confidence in managing their child’s food allergy.