SU-E-J-48: Development of An Abdominal Compression Device for Respiratory Correlated Radiation Therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, T; Kang, S; Kim, D

Purpose: The aim of this study is to develop the abdominal compression device which could control pressure level according to the abdominal respiratory motion and evaluate its feasibility. Methods: In this study, we focused on developing the abdominal compression device which could control pressure level at any point of time so the developed device is possible to use a variety of purpose (gating technique or respiratory training system) while maintaining the merit of the existing commercial device. The compression device (air pad form) was designed to be able to compress the front and side of abdomen and the pressure levelmore » of the abdomen is controlled by air flow. Pressure level of abdomen (air flow) was determined using correlation data between external abdominal motion and respiratory volume signal measured by spirometer. In order to verify the feasibility of the device, it was necessary to confirm the correlation between the abdominal respiratory motion and respiratory volume signal and cooperation with respiratory training system also checked. Results: In the previous study, we could find that the correlation coefficient ratio between diaphragm and respiratory volume signal measured by spirometer was 0.95. In this study, we confirmed the correlation between the respiratory volume signal and the external abdominal motion measured by belt-transducer (correlation coefficient ratio was 0.92) and used the correlated respiratory volume data as an abdominal pressure level. It was possible to control the pressure level with negligible time delay and respiratory volume data based guiding waveforms could be properly inserted into the respiratory training system. Conclusion: Through this feasibility study, we confirmed the correlation between the respiratory volume signal and the external abdominal motion. Also initial assessment of the device and its compatibility with the respiratory training system were verified. Further study on application in respiratory gated therapy and respiratory training system will be investigated. This work was supported by Radiation Technology R and D program (No. 2013M2A2A7043498)and Basic Atomic Energy Research Institute (BAERI)(No. NRF-2009-0078390) through the National Research Foundation of Korea funded by the Ministry of Science, ICT and Future Planning.« less

Influence of meditation on anti-correlated networks in the brain.

PubMed

Josipovic, Zoran; Dinstein, Ilan; Weber, Jochen; Heeger, David J

2011-01-01

Human experiences can be broadly divided into those that are external and related to interaction with the environment, and experiences that are internal and self-related. The cerebral cortex appears to be divided into two corresponding systems: an "extrinsic" system composed of brain areas that respond more to external stimuli and tasks and an "intrinsic" system composed of brain areas that respond less to external stimuli and tasks. These two broad brain systems seem to compete with each other, such that their activity levels over time is usually anti-correlated, even when subjects are "at rest" and not performing any task. This study used meditation as an experimental manipulation to test whether this competition (anti-correlation) can be modulated by cognitive strategy. Participants either fixated without meditation (fixation), or engaged in non-dual awareness (NDA) or focused attention (FA) meditations. We computed inter-area correlations ("functional connectivity") between pairs of brain regions within each system, and between the entire extrinsic and intrinsic systems. Anti-correlation between extrinsic vs. intrinsic systems was stronger during FA meditation and weaker during NDA meditation in comparison to fixation (without mediation). However, correlation between areas within each system did not change across conditions. These results suggest that the anti-correlation found between extrinsic and intrinsic systems is not an immutable property of brain organization and that practicing different forms of meditation can modulate this gross functional organization in profoundly different ways.

Rating Correlations Between Customs Codes and Export Control Lists: Assessing the Needs and Challenges

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chatelus, Renaud; Heine, Pete

Correlation tables are the linchpins between the customs codes used to classify commodities in international trade and the control lists used for strategic trade control (STC) purposes. While understanding the customs classification system can help the STC community better understand strategic trade flows, better identify which trade operations require permits, and more effectively detect illegal exports, the two systems are different in scope, philosophy, content, and objectives. Many indications point to the limitations of these correlation tables, and it is important to understand the nature of the limitations and the complex underlying reasons to conceive possible improvements. As part ofmore » its Strategic Trade and Supply Chain Analytics Initiative, Argonne National Laboratory supported a study of a subset of the European Union’s TARIC correlation table. The study included development of a methodology and an approach to rating the quality and relevance of individual correlations. The study was intended as a first step to engage the STC community in deflections and initiatives to improve the conception and use of correlations, and its conclusions illustrate the scope and complex nature of the challenges to overcome. This paper presents the two classification systems, analyzes the needs for correlation tables and the complex challenges associated with them, summarizes key findings, and proposes possible ways forward.« less

Signatures of bifurcation on quantum correlations: Case of the quantum kicked top

NASA Astrophysics Data System (ADS)

Bhosale, Udaysinh T.; Santhanam, M. S.

2017-01-01

Quantum correlations reflect the quantumness of a system and are useful resources for quantum information and computational processes. Measures of quantum correlations do not have a classical analog and yet are influenced by classical dynamics. In this work, by modeling the quantum kicked top as a multiqubit system, the effect of classical bifurcations on measures of quantum correlations such as the quantum discord, geometric discord, and Meyer and Wallach Q measure is studied. The quantum correlation measures change rapidly in the vicinity of a classical bifurcation point. If the classical system is largely chaotic, time averages of the correlation measures are in good agreement with the values obtained by considering the appropriate random matrix ensembles. The quantum correlations scale with the total spin of the system, representing its semiclassical limit. In the vicinity of trivial fixed points of the kicked top, the scaling function decays as a power law. In the chaotic limit, for large total spin, quantum correlations saturate to a constant, which we obtain analytically, based on random matrix theory, for the Q measure. We also suggest that it can have experimental consequences.

On the estimation of the correlation dimension and its application to radar reflector discrimination

NASA Technical Reports Server (NTRS)

Barnett, Kevin D.

1993-01-01

Recently, system theorists have recognized that low order systems of nonlinear differential equations can give rise to solutions which are neither periodic, constant, nor predictable in steady state, but which are nonetheless bounded and deterministic. This behavior, which was first described in the study of weather systems, has been termed 'chaotic.' Much study of chaotic systems has concentrated on analysis of the systems' phase space attractors. It has been recognized that invariant measures of the attractor possess inherent information about the system. One such measure is the dimension of the attractors. The dimension of a chaotic attractor has been shown to be noninteger, leading to the term 'strange attractor;' the attractor is said to have a fractal structure. The correlation dimension has become one of the most popular measures of dimension. However, many problems have been identified in correlation dimension estimation from time sequences. The most common methods for obtaining the correlation dimension have been least squares curves fitting to find the slope of the correlation integral and the Takens Estimator. However, these estimates show unacceptable sensitivity to the upper limit on the distance chosen. Here, a new method is proposed which is shown to be rather insensitive to the upper limit and to perform in a very stable manner, at least in the absence of noise. The correlation dimension is also shown to be an effective discriminant in distinguishing between radar returns resulting from weather and those from the ground. The weather returns are shown to have a correlation dimension generally between 2.0 and 3.0, while ground returns have a correlation dimension exceeding 3.0.

Correlation between the Modified Systemic Lupus Erythematosus Disease Activity Index 2000 and the European Consensus Lupus Activity Measurement in juvenile systemic lupus erythematosus.

PubMed

Sato, J O; Corrente, J E; Saad-Magalhães, C

2016-11-01

Objective The objective of this study was to assess Modified Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) and European Consensus Lupus Activity Measurement (ECLAM) disease activity correlation in addition to their respective correlation to Pediatric Systemic Lupus International Collaborative Clinics/American College of Rheumatology (SLICC/ACR) Damage Index (Ped-SDI), in juvenile systemic lupus erythematosus (JSLE). Methods The activity indices were scored retrospectively and summarized by adjusted means during follow-up. The Ped-SDI was scored during the last visit for those with more than six months follow-up. Pearson correlation between the Modified SLEDAI-2K and ECLAM, as well as Spearman correlations between the Modified SLEDAI-2K, ECLAM, and Ped-SDI were calculated. The receiver operating characteristic (ROC) curve was calculated for both activity indices discriminating damage measured by Ped-SDI. Results Thirty-seven patients with mean age at diagnosis 11 ± 2.9 years and mean follow-up time 3.2 ± 2.4 years were studied. The Modified SLEDAI-2K and ECLAM adjusted means were highly correlated ( r = 0.78, p < 0.001). Similarly, Spearman correlation between the activity indices was also high ( r s  > 0.7, p < 0.001), but Modified SLEDAI-2K and ECLAM correlation with Ped-SDI was only moderate. ROC analysis discriminant performance for both activity indices resulted in area under curve (AUC) of 0.74 and 0.73 for Modified SLEDAI-2K and ECLAM, respectively. Conclusion The high correlation found between the Modified SLEDAI-2K and ECLAM adjusted means indicated that both tools can be equally useful for longitudinal estimates of JSLE activity.

Correlation Decay in Fermionic Lattice Systems with Power-Law Interactions at Nonzero Temperature

NASA Astrophysics Data System (ADS)

Hernández-Santana, Senaida; Gogolin, Christian; Cirac, J. Ignacio; Acín, Antonio

2017-09-01

We study correlations in fermionic lattice systems with long-range interactions in thermal equilibrium. We prove a bound on the correlation decay between anticommuting operators and generalize a long-range Lieb-Robinson-type bound. Our results show that in these systems of spatial dimension D with, not necessarily translation invariant, two-site interactions decaying algebraically with the distance with an exponent α ≥2 D , correlations between such operators decay at least algebraically to 0 with an exponent arbitrarily close to α at any nonzero temperature. Our bound is asymptotically tight, which we demonstrate by a high temperature expansion and by numerically analyzing density-density correlations in the one-dimensional quadratic (free, exactly solvable) Kitaev chain with long-range pairing.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cable, J.W.

The diffuse scattering of neutrons from magnetic materials provides unique and important information regarding the spatial correlations of the atoms and the spins. Such measurements have been extensively applied to magnetically ordered systems, such as the ferromagnetic binary alloys, for which the observed correlations describe the magnetic moment fluctuations associated with local environment effects. With the advent of polarization analysis, these techniques are increasingly being applied to study disordered paramagnetic systems such as the spin-glasses and the diluted magnetic semiconductors. The spin-pair correlations obtained are essential in understanding the exchange interactions of such systems. In this paper, we describe recentmore » neutron diffuse scattering results on the atom-pair and spin-pair correlations in some of these disordered magnetic systems. 56 refs.« less

Structural instability in polyacene: A projector quantum Monte Carlo study

NASA Astrophysics Data System (ADS)

Srinivasan, Bhargavi; Ramasesha, S.

1998-04-01

We have studied polyacene within the Hubbard model to explore the effect of electron correlations on the Peierls' instability in a system marginally away from one dimension. We employ the projector quantum Monte Carlo method to obtain ground-state estimates of the energy and various correlation functions. We find strong similarities between polyacene and polyacetylene which can be rationalized from the real-space valence-bond arguments of Mazumdar and Dixit. Electron correlations tend to enhance the Peierls' instability in polyacene. This enhancement appears to attain a maximum at U/t~3.0, and the maximum shifts to larger values when the alternation parameter is increased. The system shows no tendency to destroy the imposed bond-alternation pattern, as evidenced by the bond-bond correlations. The cis distortion is seen to be favored over the trans distortion. The spin-spin correlations show that undistorted polyacene is susceptible to a spin-density-wave distortion for large interaction strength. The charge-charge correlations indicate the absence of a charge-density-wave distortion for the parameters studied.

The Importance of Parameter Variances, Correlations Lengths, and Cross-Correlations in Reactive Transport Models: Key Considerations for Assessing the Need for Microscale Information (Invited)

NASA Astrophysics Data System (ADS)

Reimus, P. W.

2010-12-01

A process-oriented modeling approach is implemented to examine the importance of parameter variances, correlation lengths, and especially cross-correlations in contaminant transport predictions over large scales. It is shown that the most important consideration is the correlation between flow rates and retardation processes (e.g., sorption, matrix diffusion) in the system. If flow rates are negatively correlated with retardation factors in systems containing multiple flow pathways, then characterizing these negative correlation(s) may have more impact on reactive transport modeling than microscale information. Such negative correlations are expected in porous-media systems where permeability is negatively correlated with clay content and rock alteration (which are usually associated with increased sorption). Likewise, negative correlations are expected in fractured rocks where permeability is positively correlated with fracture apertures, which in turn are negatively correlated with sorption and matrix diffusion. Parameter variances and correlation lengths are also shown to have important effects on reactive transport predictions, but they are less important than parameter cross-correlations. Microscale information pertaining to contaminant transport has become more readily available as characterization methods and spectroscopic instrumentation have achieved lower detection limits, greater resolution, and better precision. Obtaining detailed mechanistic insights into contaminant-rock-water interactions is becoming a routine practice in characterizing reactive transport processes in groundwater systems (almost necessary for high-profile publications). Unfortunately, a quantitative link between microscale information and flow and transport parameter distributions or cross-correlations has not yet been established. One reason for this is that quantitative microscale information is difficult to obtain in complex, heterogeneous systems, so simple systems that lack the complexity and heterogeneity of real aquifer materials are often studied. Another is that instrumentation used to obtain microscale information often probes only one variable or family of variables at a time, so linkages to other variables must be inferred by indirect means from other lines of evidence. Despite these limitations, microscale information can be useful in the development and validation of reactive transport models. For example, knowledge of mineral phases that have strong affinities for contaminants can help in the development of cross-correlations between flow and sorption parameters via characterization of permeability and mineral distributions in aquifers. Likewise, microscale information on pore structures in low-permeability zones and contaminant penetration distances into these zones from higher-permeability zones (e.g., fractures) can provide valuable constraints on the representation of diffusive mass transfer processes between flowing porosity and secondary porosity. The prioritization of obtaining microscale information in any groundwater system can be informed by modeling exercises such as those conducted for this study.

Informational correlation between two parties of a quantum system: spin-1/2 chains

NASA Astrophysics Data System (ADS)

Zenchuk, A. I.

2014-12-01

We introduce the informational correlation between two interacting quantum subsystems and of a quantum system as the number of arbitrary parameters of a unitary transformation (locally performed on the subsystem ) which may be detected in the subsystem by the local measurements. This quantity indicates whether the state of the subsystem may be effected by means of the unitary transformation applied to the subsystem . Emphasize that in general. The informational correlations in systems with tensor product initial states are studied in more details. In particular, it is shown that the informational correlation may be changed by the local unitary transformations of the subsystem . However, there is some non-reducible part of which may not be decreased by any unitary transformation of the subsystem at a fixed time instant . Two examples of the informational correlations between two parties of the four-node spin-1/2 chain with mixed initial states are studied. The long chains with a single initially excited spin (the pure initial state) are considered as well.

Influence of meditation on anti-correlated networks in the brain

PubMed Central

Josipovic, Zoran; Dinstein, Ilan; Weber, Jochen; Heeger, David J.

2012-01-01

Human experiences can be broadly divided into those that are external and related to interaction with the environment, and experiences that are internal and self-related. The cerebral cortex appears to be divided into two corresponding systems: an “extrinsic” system composed of brain areas that respond more to external stimuli and tasks and an “intrinsic” system composed of brain areas that respond less to external stimuli and tasks. These two broad brain systems seem to compete with each other, such that their activity levels over time is usually anti-correlated, even when subjects are “at rest” and not performing any task. This study used meditation as an experimental manipulation to test whether this competition (anti-correlation) can be modulated by cognitive strategy. Participants either fixated without meditation (fixation), or engaged in non-dual awareness (NDA) or focused attention (FA) meditations. We computed inter-area correlations (“functional connectivity”) between pairs of brain regions within each system, and between the entire extrinsic and intrinsic systems. Anti-correlation between extrinsic vs. intrinsic systems was stronger during FA meditation and weaker during NDA meditation in comparison to fixation (without mediation). However, correlation between areas within each system did not change across conditions. These results suggest that the anti-correlation found between extrinsic and intrinsic systems is not an immutable property of brain organization and that practicing different forms of meditation can modulate this gross functional organization in profoundly different ways. PMID:22287947

Posture and posturology, anatomical and physiological profiles: overview and current state of art.

PubMed

Carini, Francesco; Mazzola, Margherita; Fici, Chiara; Palmeri, Salvatore; Messina, Massimo; Damiani, Provvidenza; Tomasello, Giovanni

2017-04-28

posture is the position of the body in the space, and is controlled by a set of anatomical structures. The maintenance and the control of posture are a set of interactions between muscle-skeletal, visual, vestibular, and skin system. Lately there are numerous studies that correlate the muscle-skeletal and the maintenance of posture. In particular, the correction of defects and obstruction of temporomandibular disorders, seem to have an impact on posture. The aim of this work is to collect information in literature on posture and the influence of the stomatognathic system on postural system. Comparison of the literature on posture and posturology by consulting books and scientific sites. the results obtained from the comparison of the literature show a discrepancy between the thesis. Some studies support the correlation between stomatognathic system and posture, while others deny such a correlation. further studies are necessary to be able to confirm one or the other argument.

Enhancing non-local correlations in the bipartite partitions of two qubit-system with non-mutual interaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mohamed, A.-B.A., E-mail: abdelbastm@yahoo.com; Faculty of Science, Assiut University, Assiut; Joshi, A., E-mail: mcbamji@gmail.com

2016-03-15

Several quantum-mechanical correlations, notably, quantum entanglement, measurement-induced nonlocality and Bell nonlocality are studied for a two qubit-system having no mutual interaction. Analytical expressions for the measures of these quantum-mechanical correlations of different bipartite partitions of the system are obtained, for initially two entangled qubits and the two photons are in their vacuum states. It is found that the qubits-fields interaction leads to the loss and gain of the initial quantum correlations. The lost initial quantum correlations transfer from the qubits to the cavity fields. It is found that the maximal violation of Bell’s inequality is occurring when the quantum correlationsmore » of both the logarithmic negativity and measurement-induced nonlocality reach particular values. The maximal violation of Bell’s inequality occurs only for certain bipartite partitions of the system. The frequency detuning leads to quick oscillations of the quantum correlations and inhibits their transfer from the qubits to the cavity modes. It is also found that the dynamical behavior of the quantum correlation clearly depends on the qubit distribution angle.« less

Double-time correlation functions of two quantum operations in open systems

NASA Astrophysics Data System (ADS)

Ban, Masashi

2017-10-01

A double-time correlation function of arbitrary two quantum operations is studied for a nonstationary open quantum system which is in contact with a thermal reservoir. It includes a usual correlation function, a linear response function, and a weak value of an observable. Time evolution of the correlation function can be derived by means of the time-convolution and time-convolutionless projection operator techniques. For this purpose, a quasidensity operator accompanied by a fictitious field is introduced, which makes it possible to derive explicit formulas for calculating a double-time correlation function in the second-order approximation with respect to a system-reservoir interaction. The derived formula explicitly shows that the quantum regression theorem for calculating the double-time correlation function cannot be used if a thermal reservoir has a finite correlation time. Furthermore, the formula is applied for a pure dephasing process and a linear dissipative process. The quantum regression theorem and the the Leggett-Garg inequality are investigated for an open two-level system. The results are compared with those obtained by exact calculation to examine whether the formula is a good approximation.

Fictitious spin-12 operators and correlations in quadrupole nuclear spin system

NASA Astrophysics Data System (ADS)

Furman, G. B.; Goren, S. D.; Meerovich, V. M.; Sokolovsky, V. L.

The Hamiltonian and the spin operators for a spin 3/2 are represented in the basis formed by the Kronecker productions of the 2×2 Pauli matrices. This reformulation allows us to represent a spin 3/2 as a system of two coupled fictitious spins 1/2. Correlations between these fictitious spins are studied using well-developed methods. We investigate the temperature and field dependences of correlations, such as mutual information, classical correlations, entanglement, and geometric and quantum discords in the fictitious spin-1/2 system describing a nuclear spin 3/2 which is placed in magnetic and inhomogeneous electric fields. It is shown that the correlations between the fictitious spins demonstrate properties which differ from those of real two-spin systems. In contrast to real systems all the correlations between the fictitious spins do not vanish with increasing external magnetic field; at a high magnetic field the correlations tend to their limiting values. Classical correlations, quantum and geometric discords reveal a pronounced asymmetry relative to the measurements on subsystems (fictitious spins) even in a uniform magnetic field and at symmetrical EFG, η=0. The correlations depend also on the distribution of external charges, on the parameter of symmetry η. At η≠0 quantum and geometric discords have finite values in a zero magnetic field. The proposed approach may be useful in analysis of properties of particles with larger angular momentum, can provide the way to discover new physical phenomenon of quantum correlations, and can be a useful tool for similar definitions of other physical quantities of complex systems.

Quantum Engineering of Strongly Correlated Matter with Ultracold Fermi Gases

DTIC Science & Technology

2013-05-01

aim at realizing model systems of strongly correlated, disordered electrons using ultracold fermionic atoms stored in an optical "crystal". The general...theme is to study high-temperature superfluids, Fermi liquids ("metals") and insulators in the presence of disordered impurities whose influence on...Presidential Early Career Award for Science and Education (PECASE). In this program, we aim at realizing model systems of strongly correlated, disordered

A minimalistic approach to static and dynamic electron correlations: Amending generalized valence bond method with extended random phase approximation correlation correction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chatterjee, Koushik; Jawulski, Konrad; Pastorczak, Ewa

A perfect-pairing generalized valence bond (GVB) approximation is known to be one of the simplest approximations, which allows one to capture the essence of static correlation in molecular systems. In spite of its attractive feature of being relatively computationally efficient, this approximation misses a large portion of dynamic correlation and does not offer sufficient accuracy to be generally useful for studying electronic structure of molecules. We propose to correct the GVB model and alleviate some of its deficiencies by amending it with the correlation energy correction derived from the recently formulated extended random phase approximation (ERPA). On the examples ofmore » systems of diverse electronic structures, we show that the resulting ERPA-GVB method greatly improves upon the GVB model. ERPA-GVB recovers most of the electron correlation and it yields energy barrier heights of excellent accuracy. Thanks to a balanced treatment of static and dynamic correlation, ERPA-GVB stays reliable when one moves from systems dominated by dynamic electron correlation to those for which the static correlation comes into play.« less

Measuring and modeling correlations in multiplex networks.

PubMed

Nicosia, Vincenzo; Latora, Vito

2015-09-01

The interactions among the elementary components of many complex systems can be qualitatively different. Such systems are therefore naturally described in terms of multiplex or multilayer networks, i.e., networks where each layer stands for a different type of interaction between the same set of nodes. There is today a growing interest in understanding when and why a description in terms of a multiplex network is necessary and more informative than a single-layer projection. Here we contribute to this debate by presenting a comprehensive study of correlations in multiplex networks. Correlations in node properties, especially degree-degree correlations, have been thoroughly studied in single-layer networks. Here we extend this idea to investigate and characterize correlations between the different layers of a multiplex network. Such correlations are intrinsically multiplex, and we first study them empirically by constructing and analyzing several multiplex networks from the real world. In particular, we introduce various measures to characterize correlations in the activity of the nodes and in their degree at the different layers and between activities and degrees. We show that real-world networks exhibit indeed nontrivial multiplex correlations. For instance, we find cases where two layers of the same multiplex network are positively correlated in terms of node degrees, while other two layers are negatively correlated. We then focus on constructing synthetic multiplex networks, proposing a series of models to reproduce the correlations observed empirically and/or to assess their relevance.

Experimental characterization of quantum correlated triple beams generated by cascaded four-wave mixing processes

NASA Astrophysics Data System (ADS)

Qin, Zhongzhong; Cao, Leiming; Jing, Jietai

2015-05-01

Quantum correlations and entanglement shared among multiple modes are fundamental ingredients of most continuous-variable quantum technologies. Recently, a method used to generate multiple quantum correlated beams using cascaded four-wave mixing (FWM) processes was theoretically proposed and experimentally realized by our group [Z. Qin et al., Phys. Rev. Lett. 113, 023602 (2014)]. Our study of triple-beam quantum correlation paves the way to showing the tripartite entanglement in our system. Our system also promises to find applications in quantum information and precision measurement such as the controlled quantum communications, the generation of multiple quantum correlated images, and the realization of a multiport nonlinear interferometer. For its applications, the degree of quantum correlation is a crucial figure of merit. In this letter, we experimentally study how various parameters, such as the cell temperatures, one-photon, and two-photon detunings, influence the degree of quantum correlation between the triple beams generated from the cascaded two-FWM configuration.

Experimental characterization of quantum correlated triple beams generated by cascaded four-wave mixing processes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qin, Zhongzhong; Cao, Leiming; Jing, Jietai, E-mail: jtjing@phy.ecnu.edu.cn

2015-05-25

Quantum correlations and entanglement shared among multiple modes are fundamental ingredients of most continuous-variable quantum technologies. Recently, a method used to generate multiple quantum correlated beams using cascaded four-wave mixing (FWM) processes was theoretically proposed and experimentally realized by our group [Z. Qin et al., Phys. Rev. Lett. 113, 023602 (2014)]. Our study of triple-beam quantum correlation paves the way to showing the tripartite entanglement in our system. Our system also promises to find applications in quantum information and precision measurement such as the controlled quantum communications, the generation of multiple quantum correlated images, and the realization of a multiportmore » nonlinear interferometer. For its applications, the degree of quantum correlation is a crucial figure of merit. In this letter, we experimentally study how various parameters, such as the cell temperatures, one-photon, and two-photon detunings, influence the degree of quantum correlation between the triple beams generated from the cascaded two-FWM configuration.« less

High Correlated Paternity Leads to Negative Effects on Progeny Performance in Two Mediterranean Shrub Species

PubMed Central

Nora, Sofia; Aparicio, Abelardo; Albaladejo, Rafael G.

2016-01-01

Anthropogenic habitat deterioration can promote changes in plant mating systems that subsequently may affect progeny performance, thereby conditioning plant recruitment for the next generation. However, very few studies yet tested mating system parameters other than outcrossing rates; and the direct effects of the genetic diversity of the pollen received by maternal plants (i.e. correlated paternity) has often been overlooked. In this study, we investigated the relation between correlated paternity and progeny performance in two common Mediterranean shrubs, Myrtus communis and Pistacia lentiscus. To do so, we collected open-pollinated progeny from selected maternal plants, calculated mating system parameters using microsatellite genotyping and conducted sowing experiments under greenhouse and field conditions. Our results showed that some progeny fitness components were negatively affected by the high correlated paternity of maternal plants. In Myrtus communis, high correlated paternity had a negative effect on the proportion and timing of seedling emergence in the natural field conditions and in the greenhouse sowing experiment, respectively. In Pistacia lentiscus, seedling emergence time under field conditions was also negatively influenced by high correlated paternity and a progeny survival analysis in the field experiment showed greater mortality of seedlings from maternal plants with high correlated paternity. Overall, we found effects of correlated paternity on the progeny performance of Myrtus communis, a self-compatible species. Further, we also detected effects of correlated paternity on the progeny emergence time and survival in Pistacia lentiscus, an obligate outcrossed species. This study represents one of the few existing empirical examples which highlight the influence that correlated paternity may exert on progeny performance in multiple stages during early seedling growth. PMID:27835658

High Correlated Paternity Leads to Negative Effects on Progeny Performance in Two Mediterranean Shrub Species.

PubMed

Nora, Sofia; Aparicio, Abelardo; Albaladejo, Rafael G

2016-01-01

Anthropogenic habitat deterioration can promote changes in plant mating systems that subsequently may affect progeny performance, thereby conditioning plant recruitment for the next generation. However, very few studies yet tested mating system parameters other than outcrossing rates; and the direct effects of the genetic diversity of the pollen received by maternal plants (i.e. correlated paternity) has often been overlooked. In this study, we investigated the relation between correlated paternity and progeny performance in two common Mediterranean shrubs, Myrtus communis and Pistacia lentiscus. To do so, we collected open-pollinated progeny from selected maternal plants, calculated mating system parameters using microsatellite genotyping and conducted sowing experiments under greenhouse and field conditions. Our results showed that some progeny fitness components were negatively affected by the high correlated paternity of maternal plants. In Myrtus communis, high correlated paternity had a negative effect on the proportion and timing of seedling emergence in the natural field conditions and in the greenhouse sowing experiment, respectively. In Pistacia lentiscus, seedling emergence time under field conditions was also negatively influenced by high correlated paternity and a progeny survival analysis in the field experiment showed greater mortality of seedlings from maternal plants with high correlated paternity. Overall, we found effects of correlated paternity on the progeny performance of Myrtus communis, a self-compatible species. Further, we also detected effects of correlated paternity on the progeny emergence time and survival in Pistacia lentiscus, an obligate outcrossed species. This study represents one of the few existing empirical examples which highlight the influence that correlated paternity may exert on progeny performance in multiple stages during early seedling growth.

International Space Station Future Correlation Analysis Improvements

NASA Technical Reports Server (NTRS)

Laible, Michael R.; Pinnamaneni, Murthy; Sugavanam, Sujatha; Grygier, Michael

2018-01-01

Ongoing modal analyses and model correlation are performed on different configurations of the International Space Station (ISS). These analyses utilize on-orbit dynamic measurements collected using four main ISS instrumentation systems: External Wireless Instrumentation System (EWIS), Internal Wireless Instrumentation System (IWIS), Space Acceleration Measurement System (SAMS), and Structural Dynamic Measurement System (SDMS). Remote Sensor Units (RSUs) are network relay stations that acquire flight data from sensors. Measured data is stored in the Remote Sensor Unit (RSU) until it receives a command to download data via RF to the Network Control Unit (NCU). Since each RSU has its own clock, it is necessary to synchronize measurements before analysis. Imprecise synchronization impacts analysis results. A study was performed to evaluate three different synchronization techniques: (i) measurements visually aligned to analytical time-response data using model comparison, (ii) Frequency Domain Decomposition (FDD), and (iii) lag from cross-correlation to align measurements. This paper presents the results of this study.

Teacher Leadership and Teacher Efficacy: A Correlational Study Comparing Teacher Perceptions of Leadership and Efficacy and Teacher Evaluation Scores from the North Carolina Educator Evaluation System

ERIC Educational Resources Information Center

Guenzler, April M.

2016-01-01

This study sought to identify correlations between constructs of teacher leadership, teacher efficacy, and teacher evaluation. Teacher perceptual data of support of teacher leadership, perceptual data on personal teacher efficacy, and teacher self-reported scores from the North Carolina Educator Evaluation System were gathered. The relationships…

Assessing the performance of a motion tracking system based on optical joint transform correlation

NASA Astrophysics Data System (ADS)

Elbouz, M.; Alfalou, A.; Brosseau, C.; Ben Haj Yahia, N.; Alam, M. S.

2015-08-01

We present an optimized system specially designed for the tracking and recognition of moving subjects in a confined environment (such as an elderly remaining at home). In the first step of our study, we use a VanderLugt correlator (VLC) with an adapted pre-processing treatment of the input plane and a postprocessing of the correlation plane via a nonlinear function allowing us to make a robust decision. The second step is based on an optical joint transform correlation (JTC)-based system (NZ-NL-correlation JTC) for achieving improved detection and tracking of moving persons in a confined space. The proposed system has been found to have significantly superior discrimination and robustness capabilities allowing to detect an unknown target in an input scene and to determine the target's trajectory when this target is in motion. This system offers robust tracking performance of a moving target in several scenarios, such as rotational variation of input faces. Test results obtained using various real life video sequences show that the proposed system is particularly suitable for real-time detection and tracking of moving objects.

Laser correlation spectroscopy in the diagnosis of tumor diseases of the female reproductive system (preliminary results)

NASA Astrophysics Data System (ADS)

Korneeva, A. A.; Sekerskaya, M. N.; Zhordaniya, K. I.; Sapezhinskiy, V. S.; Golubtsova, N. V.; Barmashov, A. E.; Gonchukov, S. A.; Ivanov, A. V.

2017-01-01

The study of blood serum of cancer patients by laser correlation spectroscopy to determine the possibility of differentiation of benign and malignant tumors of the female reproductive system. We analyzed the data and assessed the applicability of the method mentioned above target.

Impact of Charge Degradation on the Life Cycle Climate Performance of a Residential Air-Conditioning System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beshr, Mohamed; Aute, Vikrant; Abdelaziz, Omar

2014-01-01

Vapor compression systems continuously leak a small fraction of their refrigerant charge to the environment, whether during operation or servicing. As a result of the slow leak rate occurring during operation, the refrigerant charge decreases until the system is serviced and recharged. This charge degradation, after a certain limit, begins to have a detrimental effect on system capacity, energy consumption, and coefficient of performance (COP). This paper presents a literature review and a summary of previous experimental work on the effect of undercharging or charge degradation of different vapor compression systems, especially those without a receiver. These systems include residentialmore » air conditioning and heat pump systems utilizing different components and refrigerants, and water chiller systems. Most of these studies show similar trends for the effect of charge degradation on system performance. However, it is found that although much experimental work exists on the effect of charge degradation on system performance, no correlation or comparison between charge degradation and system performance yet exists. Thus, based on the literature review, three different correlations that characterize the effect of charge on system capacity and energy consumption are developed for different systems as follows: one for air-conditioning systems, one for vapor compression water-to-water chiller systems, and one for heat pumps. These correlations can be implemented in vapor compression cycle simulation tools to obtain a better prediction of the system performance throughout its lifetime. In this paper, these correlations are implemented in an open source tool for life cycle climate performance (LCCP) based design of vapor compression systems. The LCCP of a residential air-source heat pump is evaluated using the tool and the effect of charge degradation on the results is studied. The heat pump is simulated using a validated component-based vapor compression system model and the LCCP results obtained using the three charge degradation correlations are compared.« less

Doppler ultrasound study of penis in men with systemic sclerosis: a correlation with Doppler indices of renal and digital arteries.

PubMed

Rosato, E; Barbano, B; Gigante, A; Cianci, R; Molinaro, I; Quarta, S; Digiulio, M A; Messineo, D; Pisarri, S; Salsano, F

2013-01-01

Erectile dysfunction (ED) prevalence in male systemic sclerosis (SSc) is high and its pathogenesis is unclear. The aim of the study is to assess correlation between Doppler ultrasound indices of penis and kidneys or digital arteries in male systemic sclerosis. Fourteen men with systemic sclerosis were enrolled in this study. Erectile function was investigated by the International Index of Erectile Function-5. Peak systolic velocity, end diastolic velocity, resistive index, pulsative index, and systolic/diastolic ratio were measured on the cavernous arteries at the peno-scrotal junction in the flaccid state, on the interlobar artery of both kidneys and all ten proper palmar digital arteries. Ten (71 percent) patients have an International Index of Erectile Function-5 less than 21. Reduction of penis peak systolic velocity was observed in all SSc subjects. Doppler indices of cavernous arteries correlate with the International Index of Erectile Function-5. The renal and digital arteries resistive index demonstrated a good correlation (p less than 0.0001) with International Index of Erectile Function-5. A positive correlation exists between penis and kidney arteries Doppler indices: end diastolic velocity (p less than 0.05, r=0.54), resistive index (p less than 0.0001, r=0.90), systolic/diastolic ratio (p less than 0.01, r=0.69). A positive correlation was observed between penis and digital arteries Doppler indices: peak systolic velocity (p less than 0.01, r=0.68), end diastolic velocity (p less than 0.01, r=0.75), resistive index (p less than 0.001, r=0.79), systolic/diastolic ratio (p less than 0.05, r=0.59). A correlation exists between arterial impairment of penis and renal or digital arteries.

Using internet search queries for infectious disease surveillance: screening diseases for suitability.

PubMed

Milinovich, Gabriel J; Avril, Simon M R; Clements, Archie C A; Brownstein, John S; Tong, Shilu; Hu, Wenbiao

2014-12-31

Internet-based surveillance systems provide a novel approach to monitoring infectious diseases. Surveillance systems built on internet data are economically, logistically and epidemiologically appealing and have shown significant promise. The potential for these systems has increased with increased internet availability and shifts in health-related information seeking behaviour. This approach to monitoring infectious diseases has, however, only been applied to single or small groups of select diseases. This study aims to systematically investigate the potential for developing surveillance and early warning systems using internet search data, for a wide range of infectious diseases. Official notifications for 64 infectious diseases in Australia were downloaded and correlated with frequencies for 164 internet search terms for the period 2009-13 using Spearman's rank correlations. Time series cross correlations were performed to assess the potential for search terms to be used in construction of early warning systems. Notifications for 17 infectious diseases (26.6%) were found to be significantly correlated with a selected search term. The use of internet metrics as a means of surveillance has not previously been described for 12 (70.6%) of these diseases. The majority of diseases identified were vaccine-preventable, vector-borne or sexually transmissible; cross correlations, however, indicated that vector-borne and vaccine preventable diseases are best suited for development of early warning systems. The findings of this study suggest that internet-based surveillance systems have broader applicability to monitoring infectious diseases than has previously been recognised. Furthermore, internet-based surveillance systems have a potential role in forecasting emerging infectious disease events, especially for vaccine-preventable and vector-borne diseases.

Importance of dispersion and electron correlation in ab initio protein folding.

PubMed

He, Xiao; Fusti-Molnar, Laszlo; Cui, Guanglei; Merz, Kenneth M

2009-04-16

Dispersion is well-known to be important in biological systems, but the effect of electron correlation in such systems remains unclear. In order to assess the relationship between the structure of a protein and its electron correlation energy, we employed both full system Hartree-Fock (HF) and second-order Møller-Plesset perturbation (MP2) calculations in conjunction with the Polarizable Continuum Model (PCM) on the native structures of two proteins and their corresponding computer-generated decoy sets. Because of the expense of the MP2 calculation, we have utilized the fragment molecular orbital method (FMO) in this study. We show that the sum of the Hartree-Fock (HF) energy and force field (LJ6)-derived dispersion energy (HF + LJ6) is well correlated with the energies obtained using second-order Møller-Plesset perturbation (MP2) theory. In one of the two examples studied, the correlation energy as well as the empirical dispersive energy term was able to discriminate between native and decoy structures. On the other hand, for the second protein we studied, neither the correlation energy nor dispersion energy showed discrimination capabilities; however, the ab initio MP2 energy and the HF+LJ6 both ranked the native structure correctly. Furthermore, when we randomly scrambled the Lennard-Jones parameters, the correlation between the MP2 energy and the sum of the HF energy and dispersive energy (HF+LJ6) significantly drops, which indicates that the choice of Lennard-Jones parameters is important.

On the use of two-time correlation functions for X-ray photon correlation spectroscopy data analysis.

PubMed

Bikondoa, Oier

2017-04-01

Multi-time correlation functions are especially well suited to study non-equilibrium processes. In particular, two-time correlation functions are widely used in X-ray photon correlation experiments on systems out of equilibrium. One-time correlations are often extracted from two-time correlation functions at different sample ages. However, this way of analysing two-time correlation functions is not unique. Here, two methods to analyse two-time correlation functions are scrutinized, and three illustrative examples are used to discuss the implications for the evaluation of the correlation times and functional shape of the correlations.

The importance and pitfalls of correlational science in palliative care research.

PubMed

Klepstad, Pål; Kaasa, Stein

2012-12-01

Correlational science discovers associations between patient characteristics, symptoms and biomarkers. Correlational science using data from cross-sectional studies is the most frequently applied study design in palliative care research. The purpose of this review is to address the importance and potential pitfalls in correlational science. Associations observed in correlational science studies can be the basis for generating hypotheses that can be tested in experimental studies and are the basic data needed to develop classification systems that can predict patient outcomes. Major pitfalls in correlational science are that associations do not equate with causality and that statistical significance does not necessarily equal a correlation that is of clinical interest. Researchers should be aware of the end-points that are clinically relevant, that end-points should be defined before the start of the analyses, and that studies with several end-points should account for multiplicity. Correlational science in palliative care research can identify related clinical factors and biomarkers. Interpretation of identified associations should be done with careful consideration of the limitations underlying correlational analyses.

A Study on the Correlation of Pertrochanteric Osteoporotic Fracture Severity with the Severity of Osteoporosis.

PubMed

Hayer, Prabhnoor Singh; Deane, Anit Kumar Samuel; Agrawal, Atul; Maheshwari, Rajesh; Juyal, Anil

2016-04-01

Osteoporosis is a metabolic bone disease caused by progressive bone loss. It is characterized by low Bone Mineral Density (BMD) and structural deterioration of bone tissue leading to bone fragility and increased risk of fractures. When classifying a fracture, high reliability and validity are crucial for successful treatment. Furthermore, a classification system should include severity, method of treatment, and prognosis for any given fracture. Since it is known that treatment significantly influences prognosis, a classification system claiming to include both would be desirable. Since there is no such classification system, which includes both the fracture type and the osteoporosis severity, we tried to find a correlation between fracture severity and osteoporosis severity. The aim of the study was to evaluate whether the AO/ASIF fracture classification system, which indicates the severity of fractures, has any relationship with the bone mineral status in patients with primary osteoporosis. We hypothesized that fracture severity and severity of osteoporosis should show some correlation. An observational analytical study was conducted over a period of one year during which 49 patients were included in the study at HIMS, SRH University, Dehradun. The osteoporosis status of all the included patients with a pertrochanteric fracture was documented using a DEXA scan and T-Score (BMD) was calculated. All patients had a trivial trauma. All the fractures were classified as per AO/ASIF classification. Pearson Correlation between BMD and fracture type was calculated. Data was entered on Microsoft Office Excel version 2007 and Interpretation and analysis of obtained data was done using summary statistics. Pearson Correlation between BMD and fracture type was calculated using the SPSS software version 22.0. The average age of the patients included in the study was 71.2 years and the average bone mineral density was -4.9. The correlation between BMD and fracture type was calculated and the r-values obtained was 0.180, which showed low a correlation and p-value was 0.215, which was insignificant. Statistically the pertrochanteric fracture configuration as per AO Classification does not correlate with the osteoporosis severity of the patient.

Understanding Plasmas with a High Degree of Correlation Through Modeling: From Rydberg and Fermionic Plasmas to Penning Plasmas

NASA Astrophysics Data System (ADS)

Christlieb, Andrew

2015-09-01

Ultra cold neutral plasmas have gained attention over the past 15 years as being a unique environment for studying moderately to strongly coupled neutral systems. The first ultra cold neutral plasmas were generated by ionizing a Bose Einstein condensate, generating a plasma with .1K ions and 2-4K electrons. These neutral plasmas have the unique property that the ratio of their potential energy to their kinetic energy, (Γ = PE / KE), can greatly exceed 1, leading to a strongly correlated system. The high degree of correlation means that everything from wave propagation through collision dynamics behaves quite differently from their counterpart in traditional neutral plasmas. Currently, a range of gases and different methods for cooling have been used to generate these plasmas from supersonic expansion, through penning trap configurations (reference Tom, Jake and Ed). These systems have time scales form picoseconds to milliseconds have a particle numbers from 105 to 109. These systems present a unique environment for studying the physics of correlation due to their low particle number and small size. We start by reviewing ultra cold plasmas and the current sate of the art in generating these correlated systems. Then we introduce the methods we will use for exploring these systems through direct simulation of Molecular Dynamics models; Momentum Dependent Potentials, Treecodes and Particle-Particle Particle-Mesh methods. We use these tools to look at two key areas of ultra cold plasmas; development of methods to generate a plasma with a Γ >> 1 and the impact of correlation of collisional relaxation. Our eventual goal is to use what we learn to develop models that can simulate correlation in large plasma systems that are outside of the scope of Molecular Dynamics models. In collaboration with Gautham Dharmuman, Mayur Jain, Michael Murillo and John Verboncoeur. This work it supposed by Air Force Office of Scientific Research.

Three-particle correlation functions of quasi-two-dimensional one-component and binary colloid suspensions.

PubMed

Ho, Hau My; Lin, Binhua; Rice, Stuart A

2006-11-14

We report the results of experimental determinations of the triplet correlation functions of quasi-two-dimensional one-component and binary colloid suspensions in which the colloid-colloid interaction is short ranged. The suspensions studied range in density from modestly dilute to solid. The triplet correlation function of the one-component colloid system reveals extensive ordering deep in the liquid phase. At the same density the ordering of the larger diameter component in a binary colloid system is greatly diminished by a very small amount of the smaller diameter component. The possible utilization of information contained in the triplet correlation function in the theory of melting of a quasi-two-dimensional system is briefly discussed.

A Low Cost Simulation System to Demonstrate Pilot Induced Oscillation Phenomenon

NASA Technical Reports Server (NTRS)

Ali, Syed Firasat

1997-01-01

A flight simulation system with graphics and software on Silicon Graphics computer workstations has been installed in the Flight Vehicle Design Laboratory at Tuskegee University. The system has F-15E flight simulation software from NASA Dryden which uses the graphics of SGI flight simulation demos. On the system, thus installed, a study of pilot induced oscillations is planned for future work. Preliminary research is conducted by obtaining two sets of straight level flights with pilot in the loop. In one set of flights no additional delay is used between the stick input and the appearance of airplane response on the computer monitor. In another set of flights, a 500 ms additional delay is used. The flight data is analyzed to find cross correlations between deflections of control surfaces and response of the airplane. The pilot dynamics features depicted from cross correlations of straight level flights are discussed in this report. The correlations presented here will serve as reference material for the corresponding correlations in a future study of pitch attitude tracking tasks involving pilot induced oscillations.

A new cross-correlation algorithm for the analysis of "in vitro" neuronal network activity aimed at pharmacological studies.

PubMed

Biffi, E; Menegon, A; Regalia, G; Maida, S; Ferrigno, G; Pedrocchi, A

2011-08-15

Modern drug discovery for Central Nervous System pathologies has recently focused its attention to in vitro neuronal networks as models for the study of neuronal activities. Micro Electrode Arrays (MEAs), a widely recognized tool for pharmacological investigations, enable the simultaneous study of the spiking activity of discrete regions of a neuronal culture, providing an insight into the dynamics of networks. Taking advantage of MEAs features and making the most of the cross-correlation analysis to assess internal parameters of a neuronal system, we provide an efficient method for the evaluation of comprehensive neuronal network activity. We developed an intra network burst correlation algorithm, we evaluated its sensitivity and we explored its potential use in pharmacological studies. Our results demonstrate the high sensitivity of this algorithm and the efficacy of this methodology in pharmacological dose-response studies, with the advantage of analyzing the effect of drugs on the comprehensive correlative properties of integrated neuronal networks. Copyright © 2011 Elsevier B.V. All rights reserved.

Correlations of Life Form, Pollination Mode and Sexual System in Aquatic Angiosperms

PubMed Central

Du, Zhi-Yuan; Wang, Qing-Feng

2014-01-01

Aquatic plants are phylogenetically well dispersed across the angiosperms. Reproductive and other life-history traits of aquatic angiosperms are closely associated with specific growth forms. Hydrophilous pollination exhibits notable examples of convergent evolution in angiosperm reproductive structures, and hydrophiles exhibit great diversity in sexual system. In this study, we reconstructed ancestral characters of aquatic lineages based on the phylogeny of aquatic angiosperms. Our aim is to find the correlations of life form, pollination mode and sexual system in aquatic angiosperms. Hydrophily is the adaptive evolution of completely submersed angiosperms to aquatic habitats. Hydroautogamy and maleflower-ephydrophily are the transitional stages from anemophily and entomophily to hydrophily. True hydrophily occurs in 18 submersed angiosperm genera, which is associated with an unusually high incidence of unisexual flowers. All marine angiosperms are submersed, hydrophilous species. This study would help us understand the evolution of hydrophilous pollination and its correlations with life form and sexual system. PMID:25525810

Development of advanced acreage estimation methods

NASA Technical Reports Server (NTRS)

Guseman, L. F., Jr. (Principal Investigator)

1980-01-01

The use of the AMOEBA clustering/classification algorithm was investigated as a basis for both a color display generation technique and maximum likelihood proportion estimation procedure. An approach to analyzing large data reduction systems was formulated and an exploratory empirical study of spatial correlation in LANDSAT data was also carried out. Topics addressed include: (1) development of multiimage color images; (2) spectral spatial classification algorithm development; (3) spatial correlation studies; and (4) evaluation of data systems.

Self-avoiding walk on a square lattice with correlated vacancies

NASA Astrophysics Data System (ADS)

Cheraghalizadeh, J.; Najafi, M. N.; Mohammadzadeh, H.; Saber, A.

2018-04-01

The self-avoiding walk on the square site-diluted correlated percolation lattice is considered. The Ising model is employed to realize the spatial correlations of the metric space. As a well-accepted result, the (generalized) Flory's mean-field relation is tested to measure the effect of correlation. After exploring a perturbative Fokker-Planck-like equation, we apply an enriched Rosenbluth Monte Carlo method to study the problem. To be more precise, the winding angle analysis is also performed from which the diffusivity parameter of Schramm-Loewner evolution theory (κ ) is extracted. We find that at the critical Ising (host) system, the exponents are in agreement with Flory's approximation. For the off-critical Ising system, we find also a behavior for the fractal dimension of the walker trace in terms of the correlation length of the Ising system ξ (T ) , i.e., DFSAW(T ) -DFSAW(Tc) ˜1/√{ξ (T ) } .

Modal energy analysis for mechanical systems excited by spatially correlated loads

NASA Astrophysics Data System (ADS)

Zhang, Peng; Fei, Qingguo; Li, Yanbin; Wu, Shaoqing; Chen, Qiang

2018-10-01

MODal ENergy Analysis (MODENA) is an energy-based method, which is proposed to deal with vibroacoustic problems. The performance of MODENA on the energy analysis of a mechanical system under spatially correlated excitation is investigated. A plate/cavity coupling system excited by a pressure field is studied in a numerical example, in which four kinds of pressure fields are involved, which include the purely random pressure field, the perfectly correlated pressure field, the incident diffuse field, and the turbulent boundary layer pressure fluctuation. The total energies of subsystems differ to reference solution only in the case of purely random pressure field and only for the non-excited subsystem (the cavity). A deeper analysis on the scale of modal energy is further conducted via another numerical example, in which two structural modes excited by correlated forces are coupled with one acoustic mode. A dimensionless correlation strength factor is proposed to determine the correlation strength between modal forces. Results show that the error on modal energy increases with the increment of the correlation strength factor. A criterion is proposed to establish a link between the error and the correlation strength factor. According to the criterion, the error is negligible when the correlation strength is weak, in this situation the correlation strength factor is less than a critical value.

Association between systemic inflammation and serum prostate-specific antigen in a healthy Korean population

PubMed Central

Yun, Jonghyun; Lee, Hyunyoung; Yang, Wonjae

2017-01-01

Objective Serum prostate-specific antigen (PSA) may be elevated in healthy men with systemic inflammation. We aimed to investigate the association between systemic inflammation markers and serum PSA in a healthy Korean population. Material and methods A cohort of 20,151 healthy native Korean men without prostate disease between the ages of 40 and 65 years who underwent medical checkups were studied from January 2007 to December 2013. Serum total PSA and serum C-reactive protein concentrations, neutrophil, lymphocyte, and platelet counts were determined. The neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR) were calculated. We checked the correlation between systemic inflammation markers and PSA. Results Data obtained from 18,800 healthy men were analyzed. The mean age of the study subjects was 50.72±7.62 years and the mean NLR was 1.764±0.804. Correlation analysis after adjustment for age and body mass index (BMI) revealed that neutrophil count (coefficient = 0.028, p value <0.001), and NLR (coefficient = 0.027, p value <0.001) correlated with PSA. Multivariate analysis using the full model revealed that age, neutrophil count and NLR were positively correlated with PSA (p<0.001, 0.001, and 0.043 respectively). Multivariate analysis using a stepwise model revealed that age, neutrophil count and NLR were positively correlated with PSA (p<0.001, 0.001, and 0.040, respectively) and BMI was negatively correlated with PSA (p<0.001). Conclusion Systemic inflammation markers are useful with a serum PSA in a healthy Korean population. NLR in particular is significantly associated with serum PSA. PMID:28861299

Theoretical development and first-principles analysis of strongly correlated systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Chen

A variety of quantum many-body methods have been developed for studying the strongly correlated electron systems. We have also proposed a computationally efficient and accurate approach, named the correlation matrix renormalization (CMR) method, to address the challenges. The initial implementation of the CMR method is designed for molecules which have theoretical advantages, including small size of system, manifest mechanism and strongly correlation effect such as bond breaking process. The theoretic development and benchmark tests of the CMR method are included in this thesis. Meanwhile, ground state total energy is the most important property of electronic calculations. We also investigated anmore » alternative approach to calculate the total energy, and extended this method for magnetic anisotropy energy (MAE) of ferromagnetic materials. In addition, another theoretical tool, dynamical mean- field theory (DMFT) on top of the DFT , has also been used in electronic structure calculations for an Iridium oxide to study the phase transition, which results from an interplay of the d electrons' internal degrees of freedom.« less

Correlation between serum E-selectin levels and panoramic nailfold capillaroscopy in systemic sclerosis.

PubMed

Valim, V; Assis, L S S; Simões, M F J; Trevisani, V F M; Pucinelli, M L C; Andrade, L E C

2004-09-01

E-selectin is expressed by the activated endothelium and its plasma levels are increased in patients with systemic sclerosis. Eighteen patients fulfilling the American Rheumatism Association criteria for systemic sclerosis, 15 females and 3 males, 42-70 years old, 9 with diffuse and 9 with limited forms, were sequentially recruited for this study. Serum E-selectin levels were determined by commercially available ELISA and their association with nailfold capillaroscopic abnormalities was investigated. Nailfold capillaries were analyzed by 16X magnification wide-field capillaroscopy. Two parameters on capillaroscopy were used to correlate to serum E-selectin: deletion and ectasia. Data were analyzed statistically by the Student t-test and Spearman correlation. Two-tailed P values below 0.05 were considered significant. E-selectin range was 38 to 200 ng/ml (80 +/- 39.94). There was a correlation between serum E-selectin levels and the deletion capillaroscopic score (r = 0.50, P < 0.035). This correlation was even stronger within the first 48 months of diagnosis (r = 0.63, P < 0.048). On the other hand, no association was observed between selectin and ectasia. Patients with diffuse disease presented higher serum E-selectin levels than patients with limited disease, although the difference was not statistically significant (96.44 +/- 48.04 vs 63.56 +/- 21.77 ng/dl; P = 0.08). The present study is the first showing a correlation between soluble serum E-selectin levels and alterations in capillaroscopy. The stronger correlation of deletion score in capillaroscopy in early disease suggests that serum E-selectin levels might be a useful biochemical marker of disease activity in systemic sclerosis.

Interdependent networks - Topological percolation research and application in finance

NASA Astrophysics Data System (ADS)

Zhou, Di

This dissertation covers the two major parts of my Ph.D. research: i) developing a theoretical framework of complex networks and applying simulation and numerical methods to study the robustness of the network system, and ii) applying statistical physics concepts and methods to quantitatively analyze complex systems and applying the theoretical framework to study real-world systems. In part I, we focus on developing theories of interdependent networks as well as building computer simulation models, which includes three parts: 1) We report on the effects of topology on failure propagation for a model system consisting of two interdependent networks. We find that the internal node correlations in each of the networks significantly changes the critical density of failures, which can trigger the total disruption of the two-network system. Specifically, we find that the assortativity within a single network decreases the robustness of the entire system. 2) We study the percolation behavior of two interdependent scale-free (SF) networks under random failure of 1-p fraction of nodes. We find that as the coupling strength q between the two networks reduces from 1 (fully coupled) to 0 (no coupling), there exist two critical coupling strengths q1 and q2 , which separate the behaviors of the giant component as a function of p into three different regions, and for q2 < q < q 1 , we observe a hybrid order phase transition phenomenon. 3) We study the robustness of n interdependent networks with partially support-dependent relationship both analytically and numerically. We study a starlike network of n Erdos-Renyi (ER), SF networks and a looplike network of n ER networks, and we find for starlike networks, their phase transition regions change with n, but for looplike networks the phase regions change with average degree k . In part II, we apply concepts and methods developed in statistical physics to study economic systems. We analyze stock market indices and foreign exchange daily returns for 60 countries over the period of 1999-2012. We build a multi-layer network model based on different correlation measures, and introduce a dynamic network model to simulate and analyze the initializing and spreading of financial crisis. Using different computational approaches and econometric tests, we find atypical behavior of the cross correlations and community formations in the financial networks that we study during the financial crisis of 2008. For example, the overall correlation of stock market increases during crisis while the correlation between stock market and foreign exchange market decreases. The dramatic increase in correlations between a specific nation and other nations may indicate that this nation could trigger a global financial crisis. Specifically, core countries that have higher correlations with other countries and larger Gross Domestic Product (GDP) values spread financial crisis quite effectively, yet some countries with small GDPs like Greece and Cyprus are also effective in propagating systemic risk and spreading global financial crisis.

Strong anticipation and long-range cross-correlation: Application of detrended cross-correlation analysis to human behavioral data

NASA Astrophysics Data System (ADS)

Delignières, Didier; Marmelat, Vivien

2014-01-01

In this paper, we analyze empirical data, accounting for coordination processes between complex systems (bimanual coordination, interpersonal coordination, and synchronization with a fractal metronome), by using a recently proposed method: detrended cross-correlation analysis (DCCA). This work is motivated by the strong anticipation hypothesis, which supposes that coordination between complex systems is not achieved on the basis of local adaptations (i.e., correction, predictions), but results from a more global matching of complexity properties. Indeed, recent experiments have evidenced a very close correlation between the scaling properties of the series produced by two coordinated systems, despite a quite weak local synchronization. We hypothesized that strong anticipation should result in the presence of long-range cross-correlations between the series produced by the two systems. Results allow a detailed analysis of the effects of coordination on the fluctuations of the series produced by the two systems. In the long term, series tend to present similar scaling properties, with clear evidence of long-range cross-correlation. Short-term results strongly depend on the nature of the task. Simulation studies allow disentangling the respective effects of noise and short-term coupling processes on DCCA results, and suggest that the matching of long-term fluctuations could be the result of short-term coupling processes.

Generalized-active-space pair-density functional theory: an efficient method to study large, strongly correlated, conjugated systems.

PubMed

Ghosh, Soumen; Cramer, Christopher J; Truhlar, Donald G; Gagliardi, Laura

2017-04-01

Predicting ground- and excited-state properties of open-shell organic molecules by electronic structure theory can be challenging because an accurate treatment has to correctly describe both static and dynamic electron correlation. Strongly correlated systems, i.e. , systems with near-degeneracy correlation effects, are particularly troublesome. Multiconfigurational wave function methods based on an active space are adequate in principle, but it is impractical to capture most of the dynamic correlation in these methods for systems characterized by many active electrons. We recently developed a new method called multiconfiguration pair-density functional theory (MC-PDFT), that combines the advantages of wave function theory and density functional theory to provide a more practical treatment of strongly correlated systems. Here we present calculations of the singlet-triplet gaps in oligoacenes ranging from naphthalene to dodecacene. Calculations were performed for unprecedently large orbitally optimized active spaces of 50 electrons in 50 orbitals, and we test a range of active spaces and active space partitions, including four kinds of frontier orbital partitions. We show that MC-PDFT can predict the singlet-triplet splittings for oligoacenes consistent with the best available and much more expensive methods, and indeed MC-PDFT may constitute the benchmark against which those other models should be compared, given the absence of experimental data.

Data mining in forecasting PVT correlations of crude oil systems based on Type1 fuzzy logic inference systems

NASA Astrophysics Data System (ADS)

El-Sebakhy, Emad A.

2009-09-01

Pressure-volume-temperature properties are very important in the reservoir engineering computations. There are many empirical approaches for predicting various PVT properties based on empirical correlations and statistical regression models. Last decade, researchers utilized neural networks to develop more accurate PVT correlations. These achievements of neural networks open the door to data mining techniques to play a major role in oil and gas industry. Unfortunately, the developed neural networks correlations are often limited, and global correlations are usually less accurate compared to local correlations. Recently, adaptive neuro-fuzzy inference systems have been proposed as a new intelligence framework for both prediction and classification based on fuzzy clustering optimization criterion and ranking. This paper proposes neuro-fuzzy inference systems for estimating PVT properties of crude oil systems. This new framework is an efficient hybrid intelligence machine learning scheme for modeling the kind of uncertainty associated with vagueness and imprecision. We briefly describe the learning steps and the use of the Takagi Sugeno and Kang model and Gustafson-Kessel clustering algorithm with K-detected clusters from the given database. It has featured in a wide range of medical, power control system, and business journals, often with promising results. A comparative study will be carried out to compare their performance of this new framework with the most popular modeling techniques, such as neural networks, nonlinear regression, and the empirical correlations algorithms. The results show that the performance of neuro-fuzzy systems is accurate, reliable, and outperform most of the existing forecasting techniques. Future work can be achieved by using neuro-fuzzy systems for clustering the 3D seismic data, identification of lithofacies types, and other reservoir characterization.

Robustness of networks formed from interdependent correlated networks under intentional attacks

NASA Astrophysics Data System (ADS)

Liu, Long; Meng, Ke; Dong, Zhaoyang

2018-02-01

We study the problem of intentional attacks targeting to interdependent networks generated with known degree distribution (in-degree oriented model) or distribution of interlinks (out-degree oriented model). In both models, each node's degree is correlated with the number of its links that connect to the other network. For both models, varying the correlation coefficient has a significant effect on the robustness of a system undergoing random attacks or attacks targeting nodes with low degree. For a system with an assortative relationship between in-degree and out-degree, reducing the broadness of networks' degree distributions can increase the resistance of systems against intentional attacks.

Percolation thresholds and fractal dimensions for square and cubic lattices with long-range correlated defects

NASA Astrophysics Data System (ADS)

Zierenberg, Johannes; Fricke, Niklas; Marenz, Martin; Spitzner, F. P.; Blavatska, Viktoria; Janke, Wolfhard

2017-12-01

We study long-range power-law correlated disorder on square and cubic lattices. In particular, we present high-precision results for the percolation thresholds and the fractal dimension of the largest clusters as a function of the correlation strength. The correlations are generated using a discrete version of the Fourier filtering method. We consider two different metrics to set the length scales over which the correlations decay, showing that the percolation thresholds are highly sensitive to such system details. By contrast, we verify that the fractal dimension df is a universal quantity and unaffected by the choice of metric. We also show that for weak correlations, its value coincides with that for the uncorrelated system. In two dimensions we observe a clear increase of the fractal dimension with increasing correlation strength, approaching df→2 . The onset of this change does not seem to be determined by the extended Harris criterion.

Effects of cross-correlated noises on the relaxation time of the bistable system

NASA Astrophysics Data System (ADS)

Xie, Chong-Wei; Mei, Dong-Cheng

2003-11-01

The stationary correlation function and the associated relaxation time for a general system driven by cross-correlated white noises are derived, by virtue of a Stratonovich-like ansatz. The effects of correlated noises on the relaxation time of a bistable kinetic model coupled to an additive and a multiplicative white noises are studied. It is proved that for small fluctuations the relaxation time Tc as a function of lambda (the correlated intensity between noises) exhibits very different behaviours for alphaD (alpha and D, respectively, stand for the intensities of additive and multiplicative noises). When alpha>D, Tc increases with increasing lambda. But when alpha

Comparative study of computerized dynamic posturography and the SwayStar system in healthy subjects.

PubMed

Faraldo-García, Ana; Santos-Pérez, Sofía; Crujeiras, Rosa; Labella-Caballero, Torcuato; Soto-Varela, Andrés

2012-03-01

For healthy subjects, posturography and SwayStar™ results are basically comparable, when they are obtained under the same sensory stimulation conditions. However, the management of the information and the mathematical analyses in the two systems are not comparable. Postural control represents man's ability to maintain the center of pressures inside the limits of stability. Posturography is a set of techniques that objectively studies and quantifies the postural control. The present study analyzed the different parameters of the dynamic computerized posturography and SwayStar systems related to balance, to determine whether the results of the two systems in the same healthy subject are equivalent. Seventy healthy individuals, with a mean age of 44.9 years, were homogeneously divided into seven age groups. Postural studies with a Neurocom(®) Smart Balance Master posturography platform (sensorial organization test), with the SwayStar(®) system (14 tests), and another sensorial organization test were recorded simultaneously with the two posturographs. The Pearson correlation test was used for the statistical study (p < 0.05). Comparison of the independent records showed correlation only in the Romberg position with eyes closed on a normal surface and in the Romberg position with open eyes on moving/foam surface. We found correlation for all conditions when simultaneously recorded.

Environmental Pollution by Benzene and PM10 and Clinical Manifestations of Systemic Sclerosis: A Correlation Study.

PubMed

Borghini, Alice; Poscia, Andrea; Bosello, Silvia; Teleman, Adele Anna; Bocci, Mario; Iodice, Lanfranco; Ferraccioli, Gianfranco; La Milìa, Daniele Ignazio; Moscato, Umberto

2017-10-26

Atmospheric air pollution has been associated with a range of adverse health effects. The environment plays a causative role in the development of Systemic Sclerosis (SSc). The aim of the present study is to explore the association between particulate (PM 10 ) and benzene (B) exposure in Italian patients with systemic sclerosis and their clinical characteristics of the disease. A correlation study was conducted by enrolling 88 patients who suffer from SSc at the Fondazione Policlinico "A. Gemelli" in Rome (Italy) in the period from January 2013 to January 2014. The average mean concentrations of B (in 11 monitoring sites) and PM 10 (in 14 sites) were calculated using data from the Regional Environmental Protection Agency's monitoring stations located throughout the Lazio region (Italy) and then correlated with the clinical characteristics of the SSc patients. Of the study sample, 92.5% were female. The mean age was 55 ± 12.9 years old and the mean disease duration from the onset of Raynaud's phenomenon was 13.0 ± 9.4 years. The Spearman's correlation showed that concentrations of B correlate directly with the skin score (R = 0.3; p ≤ 0.05) and inversely with Diffusing Lung Carbon Monoxide (DLCO) results (R = -0.36; p = 0.04). This study suggests a possible role of B in the development of diffuse skin disease and in a worse progression of the lung manifestations of SSc.

Neuronal Correlation Parameter and the Idea of Thermodynamic Entropy of an N-Body Gravitationally Bounded System.

PubMed

Haranas, Ioannis; Gkigkitzis, Ioannis; Kotsireas, Ilias; Austerlitz, Carlos

2017-01-01

Understanding how the brain encodes information and performs computation requires statistical and functional analysis. Given the complexity of the human brain, simple methods that facilitate the interpretation of statistical correlations among different brain regions can be very useful. In this report we introduce a numerical correlation measure that may serve the interpretation of correlational neuronal data, and may assist in the evaluation of different brain states. The description of the dynamical brain system, through a global numerical measure may indicate the presence of an action principle which may facilitate a application of physics principles in the study of the human brain and cognition.

Hybrid Learning: A Study of Training Environment and Training Transfer in Ecuador

ERIC Educational Resources Information Center

Diaz, Karla

2013-01-01

Training transfer can be analyzed in the workplace by studying the results of a validated instrument like the Learning Transfer System Inventory (LTSI) developed by Holton and Bates (2011). This correlational study used the Spearman rho correlation coefficient to examine the relationship between transfer design and opportunity to use learning as…

The dynamics of local quantum uncertainty and trace distance discord for two-qubit X states under decoherence: a comparative study

NASA Astrophysics Data System (ADS)

Slaoui, A.; Daoud, M.; Laamara, R. Ahl

2018-07-01

We employ the concepts of local quantum uncertainty and geometric quantum discord based on the trace norm to investigate the environmental effects on quantum correlations of two bipartite quantum systems. The first one concerns a two-qubit system coupled with two independent bosonic reservoirs. We show that the trace discord exhibits frozen phenomenon contrarily to local quantum uncertainty. The second scenario deals with a two-level system, initially prepared in a separable state, interacting with a quantized electromagnetic radiation. Our results show that there exists an exchange of quantum correlations between the two-level system and its surrounding which is responsible for the revival phenomenon of non-classical correlations.

Index Cohesive Force Analysis Reveals That the US Market Became Prone to Systemic Collapses Since 2002

PubMed Central

Kenett, Dror Y.; Shapira, Yoash; Madi, Asaf; Bransburg-Zabary, Sharron; Gur-Gershgoren, Gitit; Ben-Jacob, Eshel

2011-01-01

Background The 2007–2009 financial crisis, and its fallout, has strongly emphasized the need to define new ways and measures to study and assess the stock market dynamics. Methodology/Principal Findings The S&P500 dynamics during 4/1999–4/2010 is investigated in terms of the index cohesive force (ICF - the balance between the stock correlations and the partial correlations after subtraction of the index contribution), and the Eigenvalue entropy of the stock correlation matrices. We found a rapid market transition at the end of 2001 from a flexible state of low ICF into a stiff (nonflexible) state of high ICF that is prone to market systemic collapses. The stiff state is also marked by strong effect of the market index on the stock-stock correlations as well as bursts of high stock correlations reminiscence of epileptic brain activity. Conclusions/Significance The market dynamical states, stability and transition between economic states was studies using new quantitative measures. Doing so shed new light on the origin and nature of the current crisis. The new approach is likely to be applicable to other classes of complex systems from gene networks to the human brain. PMID:21556323

Quenched dynamics and spin-charge separation in an interacting topological lattice

NASA Astrophysics Data System (ADS)

Barbiero, L.; Santos, L.; Goldman, N.

2018-05-01

We analyze the static and dynamical properties of a one-dimensional topological lattice, the fermionic Su-Schrieffer-Heeger model, in the presence of on-site interactions. Based on a study of charge and spin correlation functions, we elucidate the nature of the topological edge modes, which, depending on the sign of the interactions, either display particles of opposite spin on opposite edges, or a pair and a holon. This study of correlation functions also highlights the strong entanglement that exists between the opposite edges of the system. This last feature has remarkable consequences upon subjecting the system to a quench, where an instantaneous edge-to-edge signal appears in the correlation functions characterizing the edge modes. Besides, other correlation functions are shown to propagate in the bulk according to the light cone imposed by the Lieb-Robinson bound. Our study reveals how one-dimensional lattices exhibiting entangled topological edge modes allow for a nontrivial correlation spreading, while providing an accessible platform to detect spin-charge separation using state-of-the-art experimental techniques.

Multifunctional optical correlator for picosecond ultraviolet laser pulse measurement

DOE PAGES

Rakhman, Abdurahim; Wang, Yang; Garcia, Frances; ...

2014-01-01

A compact optical correlator system that measures both the autocorrelation between two infrared (IR) lights and the cross-correlation between an IR and an ultraviolet (UV) light using a single nonlinear optical crystal has been designed and experimentally demonstrated. The rapid scanning of optical delay line, switching between auto and cross-correlations, crystal angle tuning, and data acquisition and processing are all computer controlled. Pulse widths of an IR light from a mode-locked laser are measured by the correlator and the results are compared with a direct measurement using a high-speed photodetector system. The correlator has been used to study the parametermore » dependence of the pulse width of a macropulse UV laser designed for laser-assisted hydrogen ion (H-) beam stripping for the Spallation Neutron Source at Oak Ridge National Laboratory.« less

Pair correlation functions for identifying spatial correlation in discrete domains

NASA Astrophysics Data System (ADS)

Gavagnin, Enrico; Owen, Jennifer P.; Yates, Christian A.

2018-06-01

Identifying and quantifying spatial correlation are important aspects of studying the collective behavior of multiagent systems. Pair correlation functions (PCFs) are powerful statistical tools that can provide qualitative and quantitative information about correlation between pairs of agents. Despite the numerous PCFs defined for off-lattice domains, only a few recent studies have considered a PCF for discrete domains. Our work extends the study of spatial correlation in discrete domains by defining a new set of PCFs using two natural and intuitive definitions of distance for a square lattice: the taxicab and uniform metric. We show how these PCFs improve upon previous attempts and compare between the quantitative data acquired. We also extend our definitions of the PCF to other types of regular tessellation that have not been studied before, including hexagonal, triangular, and cuboidal. Finally, we provide a comprehensive PCF for any tessellation and metric, allowing investigation of spatial correlation in irregular lattices for which recognizing correlation is less intuitive.

The correlation of Acanthamoeba from the ventilation system with other environmental parameters in commercial buildings as possible indicator for indoor air quality.

PubMed

Ooi, Soo Shen; Mak, Joon Wah; Chen, Donald K F; Ambu, Stephen

2017-02-07

The free-living protozoan Acanthamoeba is an opportunistic pathogen that is ubiquitous in our environment. However, its role in affecting indoor air quality and ill-health of indoor occupants is relatively unknown. The present study investigated the presence of Acanthamoeba from the ventilation system and its correlation with other indoor air quality parameters, used in the industry code of practice and its potential as an indicator for indoor air quality. Indoor air quality assessments were carried out in nine commercial buildings with approval from the building management, and the parameters assessed were as recommended by the Department of Occupational Safety and Health. The presence of Acanthamoeba was determined through dust swabs from the ventilation system and indoor furniture. Logistic regression was performed to study the correlation between assessed parameters and occupants' complaints. A total of 107 sampling points were assessed and 40.2% of the supplying air diffuser and blowing fan and 15% of the furniture were positive for cysts. There was a significant correlation between Acanthamoeba detected from the ventilation system with ambient total fungus count (r=0.327; p=0.01) and respirable particulates (r=0.276; p=0.01). Occupants' sick building syndrome experience also correlated with the presence of Acanthamoeba in the ventilation system (r=0.361; p=0.01) and those detected on the furniture (r=0.290; p=0.01). Logistic regression showed that there was a five-fold probability of sick building syndrome among occupants when Acanthamoeba was detected in the ventilation system.

The correlation of Acanthamoeba from the ventilation system with other environmental parameters in commercial buildings as possible indicator for indoor air quality

PubMed Central

OOI, Soo Shen; MAK, Joon Wah; CHEN, Donald K.F.; AMBU, Stephen

2016-01-01

The free-living protozoan Acanthamoeba is an opportunistic pathogen that is ubiquitous in our environment. However, its role in affecting indoor air quality and ill-health of indoor occupants is relatively unknown. The present study investigated the presence of Acanthamoeba from the ventilation system and its correlation with other indoor air quality parameters, used in the industry code of practice and its potential as an indicator for indoor air quality. Indoor air quality assessments were carried out in nine commercial buildings with approval from the building management, and the parameters assessed were as recommended by the Department of Occupational Safety and Health. The presence of Acanthamoeba was determined through dust swabs from the ventilation system and indoor furniture. Logistic regression was performed to study the correlation between assessed parameters and occupants’ complaints. A total of 107 sampling points were assessed and 40.2% of the supplying air diffuser and blowing fan and 15% of the furniture were positive for cysts. There was a significant correlation between Acanthamoeba detected from the ventilation system with ambient total fungus count (r=0.327; p=0.01) and respirable particulates (r=0.276; p=0.01). Occupants’ sick building syndrome experience also correlated with the presence of Acanthamoeba in the ventilation system (r=0.361; p=0.01) and those detected on the furniture (r=0.290; p=0.01). Logistic regression showed that there was a five-fold probability of sick building syndrome among occupants when Acanthamoeba was detected in the ventilation system. PMID:27476379

Faithful nonclassicality indicators and extremal quantum correlations in two-qubit states

NASA Astrophysics Data System (ADS)

Girolami, Davide; Paternostro, Mauro; Adesso, Gerardo

2011-09-01

The state disturbance induced by locally measuring a quantum system yields a signature of nonclassical correlations beyond entanglement. Here, we present a detailed study of such correlations for two-qubit mixed states. To overcome the asymmetry of quantum discord and the unfaithfulness of measurement-induced disturbance (severely overestimating quantum correlations), we propose an ameliorated measurement-induced disturbance as nonclassicality indicator, optimized over joint local measurements, and we derive its closed expression for relevant two-qubit states. We study its analytical relation with discord, and characterize the maximally quantum-correlated mixed states, that simultaneously extremize both quantifiers at given von Neumann entropy: among all two-qubit states, these states possess the most robust quantum correlations against noise.

Correlational approach to study interactions between dust Brownian particles in a plasma

NASA Astrophysics Data System (ADS)

Lisin, E. A.; Vaulina, O. S.; Petrov, O. F.

2018-01-01

A general approach to the correlational analysis of Brownian motion of strongly coupled particles in open dissipative systems is described. This approach can be applied to the theoretical description of various non-ideal statistically equilibrium systems (including non-Hamiltonian systems), as well as for the analysis of experimental data. In this paper, we consider an application of the correlational approach to the problem of experimental exploring the wake-mediated nonreciprocal interactions in complex plasmas. We derive simple analytic equations, which allows one to calculate the gradients of forces acting on a microparticle due to each of other particles as well as the gradients of external field, knowing only the information on time-averaged correlations of particles displacements and velocities. We show the importance of taking dissipative and random processes into account, without which consideration of a system with a nonreciprocal interparticle interaction as linearly coupled oscillators leads to significant errors in determining the characteristic frequencies in a system. In the examples of numerical simulations, we demonstrate that the proposed original approach could be an effective instrument in exploring the longitudinal wake structure of a microparticle in a plasma. Unlike the previous attempts to study the wake-mediated interactions in complex plasmas, our method does not require any external perturbations and is based on Brownian motion analysis only.

Utility of Urinary Protein-Creatinine Ratio and Protein Content in a 24-Hour Urine Collection in Systemic Lupus Erythematosus: A Systematic Review and Meta-Analysis.

PubMed

Medina-Rosas, Jorge; Yap, Kristy S; Anderson, Melanie; Su, Jiandong; Touma, Zahi

2016-09-01

To systematically review literature on the utility of spot urinary protein-creatinine ratio (PCR) as a screening test for proteinuria and its ability to accurately measure proteinuria compared with 24-hour urine collection (24H-P) in patients with systemic lupus erythematosus (SLE). We conducted a literature search (1900-2015) for articles comparing PCR and 24H-P in SLE patients in the databases Medline, Web of Science, and Embase. Included studies and their results were critically appraised and analyzed. Thirteen studies (1,001 patients; 84.01% women) were included. Ten studies reported on Pearson's correlation (range 0.67-0.94), and 3 studies reported on Spearman's correlation (range 0.78-1.00). The meta-analysis of studies with Pearson's correlation showed a high overall correlation of 0.80 between 24H-P and PCR, yet with high heterogeneity (I(2)  = 97.2%). Correlation analysis is not sufficient to evaluate the utility of a new test against the gold standard test, and analysis on agreement is required. Seven studies reported on agreement: 3 studies analyzed concordance correlation coefficient (0.48-0.94), 3 analyzed intraclass correlation coefficient (0.66-0.95), and 1 analyzed kappa coefficient (0.58). These results confirmed that the agreement between 24H-P and PCR was inappropriate. Three studies included Bland-Altman plots, and the results also demonstrated poor agreement between both tests. The PCR has a utility as a screening test for proteinuria in SLE patients. The studies' results of 24H-P and PCR showed poor agreement between both tests, signifying that PCR should not be a substitute for the gold standard test (24H-P) to accurately measure proteinuria. © 2016, American College of Rheumatology.

Effect of Heterogeneity on Decorrelation Mechanisms in Spiking Neural Networks: A Neuromorphic-Hardware Study

NASA Astrophysics Data System (ADS)

Pfeil, Thomas; Jordan, Jakob; Tetzlaff, Tom; Grübl, Andreas; Schemmel, Johannes; Diesmann, Markus; Meier, Karlheinz

2016-04-01

High-level brain function, such as memory, classification, or reasoning, can be realized by means of recurrent networks of simplified model neurons. Analog neuromorphic hardware constitutes a fast and energy-efficient substrate for the implementation of such neural computing architectures in technical applications and neuroscientific research. The functional performance of neural networks is often critically dependent on the level of correlations in the neural activity. In finite networks, correlations are typically inevitable due to shared presynaptic input. Recent theoretical studies have shown that inhibitory feedback, abundant in biological neural networks, can actively suppress these shared-input correlations and thereby enable neurons to fire nearly independently. For networks of spiking neurons, the decorrelating effect of inhibitory feedback has so far been explicitly demonstrated only for homogeneous networks of neurons with linear subthreshold dynamics. Theory, however, suggests that the effect is a general phenomenon, present in any system with sufficient inhibitory feedback, irrespective of the details of the network structure or the neuronal and synaptic properties. Here, we investigate the effect of network heterogeneity on correlations in sparse, random networks of inhibitory neurons with nonlinear, conductance-based synapses. Emulations of these networks on the analog neuromorphic-hardware system Spikey allow us to test the efficiency of decorrelation by inhibitory feedback in the presence of hardware-specific heterogeneities. The configurability of the hardware substrate enables us to modulate the extent of heterogeneity in a systematic manner. We selectively study the effects of shared input and recurrent connections on correlations in membrane potentials and spike trains. Our results confirm that shared-input correlations are actively suppressed by inhibitory feedback also in highly heterogeneous networks exhibiting broad, heavy-tailed firing-rate distributions. In line with former studies, cell heterogeneities reduce shared-input correlations. Overall, however, correlations in the recurrent system can increase with the level of heterogeneity as a consequence of diminished effective negative feedback.

Cross-correlation between EMG and center of gravity during quiet stance: theory and simulations.

PubMed

Kohn, André Fabio

2005-11-01

Several signal processing tools have been employed in the experimental study of the postural control system in humans. Among them, the cross-correlation function has been used to analyze the time relationship between signals such as the electromyogram and the horizontal projection of the center of gravity. The common finding is that the electromyogram precedes the biomechanical signal, a result that has been interpreted in different ways, for example, the existence of feedforward control or the preponderance of a velocity feedback. It is shown here, analytically and by simulation, that the cross-correlation function is dependent in a complicated way on system parameters and on noise spectra. Results similar to those found experimentally, e.g., electromyogram preceding the biomechanical signal may be obtained in a postural control model without any feedforward control and without any velocity feedback. Therefore, correct interpretations of experimentally obtained cross-correlation functions may require additional information about the system. The results extend to other biomedical applications where two signals from a closed loop system are cross-correlated.

SCES2016 Summary: Experiment

DOE PAGES

Thompson, Joe David

2016-08-03

Experimental results presented during the 2016 International Conference on Strongly Correlated Electron Systems (SECS2016) not only reflect the breadth of topics being explored in the field of strongly correlated systems but also the remarkable progress in discovery and understanding that is being made from their study. Lastly, this brief summary highlights just a few of the exciting experimental developments discussed at SCES2016.

USE OF THE GEOGRAPHIC INFORMATION SYSTEM TO INVESTIGATE MERCURY LEVELS IN CORRELATION WITH POSTMORTEM FINDINGS OF ASPERGILLUS INDUCED LESIONS IN THE COMMON LOON (GAVIA IMMER) IN THE NORTHEASTERN USA

EPA Science Inventory

This study employed the Geographic Information System (GIS) to correlate total mercury levels in liver tissue with post-mortem findings of aspergillosis in common loons (Gavia immer) in the northeast United States of America (USA). Aspergillosis is an opportunistic fungal infecti...

Cerebrospinal fluid and plasma C-reactive protein and aggression in personality-disordered subjects: a pilot study.

PubMed

Coccaro, Emil F; Lee, Royce; Coussons-Read, Mary

2015-02-01

C-reactive protein (CRP), in the plasma, serves as a marker of systemic inflammation and has been shown to correlate with history of actual aggressive behavior, and as a personality trait of aggressive tendency, in human subjects. This pilot study was conducted to determine if plasma CRP levels are correlated with cerebrospinal fluid levels (CSF CRP) and if CSF CRP also correlates with aggression. If so, this would suggest a role for central inflammatory processes in human aggression. Both plasma and basal lumbar CSF samples were obtained from 17 subjects with DSM-5 personality disorder and assayed for CRP. Plasma and CSF CRP levels were correlated (r = 0.65, p = 0.005) and each correlated with aggression (Plasma: r = 0.53, p = 0.029; CSF: r = 0.84, p < 0.001). When considered simultaneously, CSF CRP, but not plasma CRP, uniquely correlated with aggression. No relationship was seen with other measures of psychopathology. These data suggest a positive relationship between central nervous system CRP and aggression in humans.

Non-Fermi liquids in oxide heterostructures

NASA Astrophysics Data System (ADS)

Stemmer, Susanne; Allen, S. James

2018-06-01

Understanding the anomalous transport properties of strongly correlated materials is one of the most formidable challenges in condensed matter physics. For example, one encounters metal-insulator transitions, deviations from Landau Fermi liquid behavior, longitudinal and Hall scattering rate separation, a pseudogap phase, and bad metal behavior. These properties have been studied extensively in bulk materials, such as the unconventional superconductors and heavy fermion systems. Oxide heterostructures have recently emerged as new platforms to probe, control, and understand strong correlation phenomena. This article focuses on unconventional transport phenomena in oxide thin film systems. We use specific systems as examples, namely charge carriers in SrTiO3 layers and interfaces with SrTiO3, and strained rare earth nickelate thin films. While doped SrTiO3 layers appear to be a well behaved, though complex, electron gas or Fermi liquid, the rare earth nickelates are a highly correlated electron system that may be classified as a non-Fermi liquid. We discuss insights into the underlying physics that can be gained from studying the emergence of non-Fermi liquid behavior as a function of the heterostructure parameters. We also discuss the role of lattice symmetry and disorder in phenomena such as metal-insulator transitions in strongly correlated heterostructures.

The association between computer literacy and training on clinical productivity and user satisfaction in using the electronic medical record in Saudi Arabia.

PubMed

Alasmary, May; El Metwally, Ashraf; Househ, Mowafa

2014-08-01

The association of computer literacy, training on clinical productivity and satisfaction of a recently implemented Electronic Medical Record (EMR) system in Prince Sultan Medical Military City ((PSMMC)) was investigated. The scope of this study was to explore the association between age, occupation and computer literacy and clinical productivity and users' satisfaction of the newly implemented EMR at PSMMC as well as the association of user satisfaction with age and position. A self-administrated questionnaire was distributed to all doctors and nurses working in Alwazarat Family and Community Center (a Health center in PSMMC). A convenience sample size of 112 healthcare providers (65 Nurses and 47 physicians) completed the questionnaire. A combination of correlation, One Way ANOVA and t-tests were used to answer the research questions. Participants had high levels of self-reported literacy on computers and satisfaction of the system. Both levels were higher among physicians than among nurses. A moderate but significant (at p < 0.01 level) correlation was found between computer literacy and users' satisfaction towards the system (R = 0.343). Age was weakly, but significantly (at p < 0.05), positively correlated with satisfaction with the system (R = 0.29). Self-reported system productivity and satisfaction was statistically correlated at p < 0.01 (R = 0.509). High level of satisfaction with training on using the system was not positively correlated with overall satisfaction of using the system. This study demonstrated that EMR users with high computer literacy skills were more satisfied with using the EMR than users with low computer literacy skills.

Evaluation of the Correlation Coefficient of Polyethylene Glycol Treated and Direct Prolactin Results and Comparability with Different Assay System Results.

PubMed

Pal, Shyamali

2017-12-01

The presence of Macro prolactin is a significant cause of elevated prolactin resulting in misdiagnosis in all automated systems. Poly ethylene glycol (PEG) pretreatment is the preventive process but such process includes the probability of loss of a fraction of bioactive prolactin. Surprisingly, PEG treated EQAS & IQAS samples in Cobas e 411 are found out to be correlating with direct results of at least 3 immunoassay systems and treated and untreated Cobas e 411 results are comparable by a correlation coefficient. Comparison of EQAS, IQAS and patient samples were done to find out the trueness of such correlation factor. Study with patient's results have established the correlation coefficient is valid for very small concentration of prolactin also. EQAS, IQAS and 150 patient samples were treated with PEG and prolactin results of treated and untreated samples obtained from Roche Cobas e 411. 25 patient's results (treated) were compared with direct results in Advia Centaur, Architect I & Access2 systems. Correlation coefficient was obtained from trend line of the treated and untreated results. Two tailed p-value obtained from regression coefficient(r) and sample size. The correlation coefficient is in the range (0.761-0.771). Reverse correlation range is (1.289-1.301). r value of two sets of calculated results were 0.995. Two tailed p- value is zero approving dismissal of null hypothesis. The z-score of EQAS does not always assure authenticity of resultsPEG precipitation is correlated by the factor 0.761 even in very small concentrationsAbbreviationsGFCgel filtration chromatographyPEGpolyethylene glycolEQASexternal quality assurance systemM-PRLmacro prolactinPRLprolactinECLIAelectro-chemiluminescence immunoassayCLIAclinical laboratory improvement amendmentsIQASinternal quality assurance systemrregression coefficient.

Density matrix renormalization group study of Y-junction spin systems

NASA Astrophysics Data System (ADS)

Guo, Haihui

Junction systems are important to understand both from the fundamental and the practical point of view, as they are essential components in existing and future electronic and spintronic devices. With the continuous advance of technology, device size will eventual reach the atomic scale. Some of the most interesting and useful junction systems will be strongly correlated. We chose the Density Matrix Renormalization Group method to study two types of Y-junction systems, the Y and YDelta junctions, on strongly correlated spin chains. With new ideas coming from the quantum information field, we have made a very efficient. Y-junction DMRG algorithm, which improves the overall CUB cost from O(m6) to O(m4), where m is the number of states kept per block. We studied the ground state properties, the correlation length, and investigated the degeneracy problem on the Y and YDelta junctions. For the excited states, we researched the existence of magnon bound states for various conditions, and have shown that the bound state exists when the central coupling constant is small.

Nondynamical correlation energy in model molecular systems

NASA Astrophysics Data System (ADS)

Chojnacki, Henryk

The hypersurfaces for the deprotonation processes have been studied at the nonempirical level for H3O+, NH+4, PH+4, and H3S+ cations within their correlation consistent basis set. The potential energy curves were calculated and nondynamical correlation energies analyzed. We have found that the restricted Hartree-Fock wavefunction leads to the improper dissociation limit and, in the three latest cases requires multireference description. We conclude that these systems may be treated as a good models for interpretation of the proton transfer mechanism as well as for testing one-determinantal or multireference cases.

Memory and reward systems coproduce 'nostalgic' experiences in the brain.

PubMed

Oba, Kentaro; Noriuchi, Madoka; Atomi, Tomoaki; Moriguchi, Yoshiya; Kikuchi, Yoshiaki

2016-07-01

People sometimes experience an emotional state known as 'nostalgia', which involves experiencing predominantly positive emotions while remembering autobiographical events. Nostalgia is thought to play an important role in psychological resilience. Previous neuroimaging studies have shown involvement of memory and reward systems in such experiences. However, it remains unclear how these two systems are collaboratively involved with nostalgia experiences. Here, we conducted a functional magnetic resonance imaging study of healthy females to investigate the relationship between memory-reward co-activation and nostalgia, using childhood-related visual stimuli. Moreover, we examined the factors constituting nostalgia and their neural correlates. We confirmed the presence of nostalgia-related activity in both memory and reward systems, including the hippocampus (HPC), substantia nigra/ventral tegmental area (SN/VTA), and ventral striatum (VS). We also found significant HPC-VS co-activation, with its strength correlating with individual 'nostalgia tendencies'. Factor analyses showed that two dimensions underlie nostalgia: emotional and personal significance and chronological remoteness, with the former correlating with caudal SN/VTA and left anterior HPC activity, and the latter correlating with rostral SN/VTA activity. These findings demonstrate the cooperative activity of memory and reward systems, where each system has a specific role in the construction of the factors that underlie the experience of nostalgia. © The Author (2015). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Gut microbes in correlation with mood: case study in a closed experimental human life support system.

PubMed

Li, L; Su, Q; Xie, B; Duan, L; Zhao, W; Hu, D; Wu, R; Liu, H

2016-08-01

Gut microbial community, which may influence our mood, can be shaped by modulating the gut ecosystem through dietary strategies. Understanding the gut-brain correlationship in healthy people is important for maintenance of mental health and prevention of mental illnesses. A case study on the correlation between gut microbial alternation and mood swing of healthy adults was conducted in a closed human life support system during a 105-day experiment. Gut microbial community structures were analyzed using high-throughput sequencing every 2 weeks. A profile of mood states questionnaire was used to record the mood swings. Correlation between gut microbes and mood were identified with partial least squares discrimination analysis. Microbial community structures in the three healthy adults were strongly correlated with mood states. Bacterial genera Roseburia, Phascolarctobacterium, Lachnospira, and Prevotella had potential positive correlation with positive mood, while genera Faecalibacterium, Bifidobacterium, Bacteroides, Parabacteroides, and Anaerostipes were correlated with negative mood. Among which, Faecalibacterium spp. had the highest abundance, and showed a significant negative correlation with mood. Our results indicated that the composition of microbial community could play a role in emotional change in mentally physically healthy adults. © 2016 John Wiley & Sons Ltd.

Solute–solute correlations responsible for the prepeak in structure factors of undercooled Al-rich liquids: A molecular dynamics study

DOE PAGES

Zhang, Feng; Sun, Yang; Ye, Zhuo; ...

2015-05-06

In this study, we have performed molecular dynamics simulations on a typical Al-based alloy Al 90Sm 10. The short-range and medium-range correlations of the system are reliably produced by ab initio calculations, whereas the long-range correlations are obtained with the assistance of a semi-empirical potential well-fitted to ab initio data. Our calculations show that a prepeak in the structure factor of this system emerges well above the melting temperature, and the intensity of the prepeak increases with increasing undercooling of the liquid. These results are in agreement with x-ray diffraction experiments. The interplay between the short-range order of the systemmore » originating from the large affinity between Al and Sm atoms, and the intrinsic repulsion between Sm atoms gives rise to a stronger correlation in the second peak than the first peak in the Sm–Sm partial pair correlation function (PPCF), which in turn produces the prepeak in the structure factor.« less

In Vivo Fluorescence Correlation and Cross-Correlation Spectroscopy

NASA Astrophysics Data System (ADS)

Mütze, Jörg; Ohrt, Thomas; Petrášek, Zdeněk; Schwille, Petra

In this manuscript, we describe the application of Fluorescence Correlation Spectroscopy (FCS), Fluorescence Cross-Correlation Spectroscopy (FCCS), and scanning FCS (sFCS) to two in vivo systems. In the first part, we describe the application of two-photon standard and scanning FCS in Caenorhabditis elegans embryos. The differentiation of a single fertilized egg into a complex organism in C. elegans is regulated by a number of protein-dependent processes. The oocyte divides asymmetrically into two daughter cells of different developmental fate. Two of the involved proteins, PAR-2 and NMY-2, are studied. The second investigated system is the mechanism of RNA interference in human cells. An EGFP based cell line that allows to study the dynamics and localization of the RNA-induced silencing complex (RISC) with FCS in vivo is created, which has so far been inaccessible with other experimental methods. Furthermore, Fluorescence Cross-Correlation Spectroscopy is employed to highlight the asymmetric incorporation of labeled siRNAs into RISC.

Quantifying meta-correlations in financial markets

NASA Astrophysics Data System (ADS)

Kenett, Dror Y.; Preis, Tobias; Gur-Gershgoren, Gitit; Ben-Jacob, Eshel

2012-08-01

Financial markets are modular multi-level systems, in which the relationships between the individual components are not constant in time. Sudden changes in these relationships significantly affect the stability of the entire system, and vice versa. Our analysis is based on historical daily closing prices of the 30 components of the Dow Jones Industrial Average (DJIA) from March 15th, 1939 until December 31st, 2010. We quantify the correlation among these components by determining Pearson correlation coefficients, to investigate whether mean correlation of the entire portfolio can be used as a precursor for changes in the index return. To this end, we quantify the meta-correlation - the correlation of mean correlation and index return. We find that changes in index returns are significantly correlated with changes in mean correlation. Furthermore, we study the relationship between the index return and correlation volatility - the standard deviation of correlations for a given time interval. This parameter provides further evidence of the effect of the index on market correlations and their fluctuations. Our empirical findings provide new information and quantification of the index leverage effect, and have implications to risk management, portfolio optimization, and to the increased stability of financial markets.

Effects of cross correlation on the relaxation time of a bistable system driven by cross-correlated noise

NASA Astrophysics Data System (ADS)

Mei, Dongcheng; Xie, Chongwei; Zhang, Li

2003-11-01

We study the effects of correlations between additive and multiplicative noise on relaxation time in a bistable system driven by cross-correlated noise. Using the projection-operator method, we derived an analytic expression for the relaxation time Tc of the system, which is the function of additive (α) and multiplicative (D) noise intensities, correlation intensity λ of noise, and correlation time τ of noise. After introducing a noise intensity ratio and a dimensionless parameter R=D/α, and then performing numerical computations, we find the following: (i) For the case of R<1, the relaxation time Tc increases as R increases. (ii) For the cases of R⩾1, there is a one-peak structure on the Tc-R plot and the effects of cross-correlated noise on the relaxation time are very notable. (iii) For the case of R<1, Tc almost does not change with both λ and τ, and for the cases of R⩾1, Tc decreases as λ increases, however Tc increases as τ increases. λ and τ play opposite roles in Tc, i.e., λ enhances the fluctuation decay of dynamical variable and τ slows down the fluctuation decay of dynamical variable.

Desktop chaotic systems: Intuition and visualization

NASA Technical Reports Server (NTRS)

Bright, Michelle M.; Melcher, Kevin J.; Qammar, Helen K.; Hartley, Tom T.

1993-01-01

This paper presents a dynamic study of the Wildwood Pendulum, a commercially available desktop system which exhibits a strange attractor. The purpose of studying this chaotic pendulum is twofold: to gain insight in the paradigmatic approach of modeling, simulating, and determining chaos in nonlinear systems; and to provide a desktop model of chaos as a visual tool. For this study, the nonlinear behavior of this chaotic pendulum is modeled, a computer simulation is performed, and an experimental performance is measured. An assessment of the pendulum in the phase plane shows the strange attractor. Through the use of a box-assisted correlation dimension methodology, the attractor dimension is determined for both the model and the experimental pendulum systems. Correlation dimension results indicate that the pendulum and the model are chaotic and their fractal dimensions are similar.

Use of statistical study methods for the analysis of the results of the imitation modeling of radiation transfer

NASA Astrophysics Data System (ADS)

Alekseenko, M. A.; Gendrina, I. Yu.

2017-11-01

Recently, due to the abundance of various types of observational data in the systems of vision through the atmosphere and the need for their processing, the use of various methods of statistical research in the study of such systems as correlation-regression analysis, dynamic series, variance analysis, etc. is actual. We have attempted to apply elements of correlation-regression analysis for the study and subsequent prediction of the patterns of radiation transfer in these systems same as in the construction of radiation models of the atmosphere. In this paper, we present some results of statistical processing of the results of numerical simulation of the characteristics of vision systems through the atmosphere obtained with the help of a special software package.1

Suppression of the "Quasiclassical" proximity gap in correlated-metal--superconductor structures.

PubMed

Nikolić, Branislav K; Freericks, J K; Miller, P

2002-02-18

We study the energy and spatial dependence of the local density of states in a superconductor--correlated-metal--superconductor Josephson junction, where the correlated metal is a non-Fermi liquid (described by the Falicov-Kimball model). Many-body correlations are treated with dynamical mean-field theory, extended to inhomogeneous systems. While quasiclassical theories predict a minigap in the spectrum of a disordered Fermi liquid which is proximity-coupled within a mesoscopic junction, we find that increasing electron correlations destroy any minigap that might be opened in the absence of many-body correlations.

Low Frequency Quasi-periodic Oscillations in the High-eccentric LMXB Cir X-1: Extending the WK Correlation for Z Sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bu, Qingcui; Chen, Li; Belloni, T. M.

Using archival Rossi X-ray Timing Explorer ( RXTE ) data, we studied the low-frequency quasi-periodic oscillations (LFQPOs) in the neutron star low-mass X-ray binary (LMXB) Cir X-1 and examined their contribution to frequency–frequency correlations for Z sources. We also studied the orbital phase effects on the LFQPO properties and found them to be phase independent. Comparing LFQPO frequencies in different classes of LMXBs, we found that systems that show both Z and atoll states form a common track with atoll/BH sources in the so-called WK correlation, while persistent Z systems are offset by a factor of about two. We foundmore » that neither source luminosity nor mass accretion rate is related to the shift of persistent Z systems. We discuss the possibility of a misidentification of fundamental frequency for horizontal branch oscillations from persistent Z systems and interpreted the oscillations in terms of models based on relativistic precession.« less

In-flight flow visualization results from the X-29A aircraft at high angles of attack

NASA Technical Reports Server (NTRS)

Delfrate, John H.; Saltzman, John A.

1992-01-01

Flow visualization techniques were used on the X-29A aircraft at high angles of attack to study the vortical flow off the forebody and the surface flow on the wing and tail. The forebody vortex system was studied because asymmetries in the vortex system were suspected of inducing uncommanded yawing moments at zero sideslip. Smoke enabled visualization of the vortex system and correlation of its orientation with flight yawing moment data. Good agreement was found between vortex system asymmetries and the occurrence of yawing moments. Surface flow on the forward-swept wing of the X-29A was studied using tufts and flow cones. As angle of attack increased, separated flow initiated at the root and spread outboard encompassing the full wing by 30 deg angle of attack. In general, the progression of the separated flow correlated well with subscale model lift data. Surface flow on the vertical tail was also studied using tufts and flow cones. As angle of attack increased, separated flow initiated at the root and spread upward. The area of separated flow on the vertical tail at angles of attack greater than 20 deg correlated well with the marked decrease in aircraft directional stability.

The investigation of the lateral interaction effect's on traffic flow behavior under open boundaries

NASA Astrophysics Data System (ADS)

Bouadi, M.; Jetto, K.; Benyoussef, A.; El Kenz, A.

2017-11-01

In this paper, an open boundaries traffic flow system is studied by taking into account the lateral interaction with spatial defects. For a random defects distribution, if the vehicles velocities are weakly correlated, the traffic phases can be predicted by considering the corresponding inflow and outflow functions. Conversely, if the vehicles velocities are strongly correlated, a phase segregation appears inside the system's bulk which induces the maximum current appearance. Such velocity correlation depends mainly on the defects densities and the probabilities of lateral deceleration. However, for a compact defects distribution, the traffic phases are predictable by using the inflow in the system beginning, the inflow entering the defects zone and the outflow function.

Is there a link between the hospital-acquired injurious fall rates in US acute care hospitals and these institutions' implementation levels of computerized systems?

PubMed

Tzeng, Huey-Ming; Hu, Hsou Mei; Yin, Chang-Yi

2011-12-01

Medicare no longer reimburses acute care hospitals for the costs of additional care required due to hospital-acquired injuries. Consequently, this study explored the effective computerized systems to inform practice for better interventions to reduce fall risk. It provided a correlation between type of computerized system and hospital-acquired injurious fall rates at acute care hospitals in California, Florida, and New York. It used multiple publicly available data sets, with the hospital as the unit of analysis. Descriptive and Pearson correlation analyses were used. The analysis included 462 hospitals. Significant correlations could be categorized into two groups: (1) meaningful computerized systems that were associated with lower injurious fall rates: the decision support systems for drug allergy alerts, drug-drug interaction alerts, and drug-laboratory interaction alerts; and (2) computerized systems that were associated with higher injurious fall rates: the decision support system for drug-drug interaction alerts and the computerized provider order entry system for radiology tests. Future research may include additional states, multiple years of data, and patient-level data to validate this study's findings. This effort may further inform policy makers and the public about effective clinical computerized systems provided to clinicians to improve their practice decisions and care outcomes.

Uncovering many-body correlations in nanoscale nuclear spin baths by central spin decoherence

PubMed Central

Ma, Wen-Long; Wolfowicz, Gary; Zhao, Nan; Li, Shu-Shen; Morton, John J.L.; Liu, Ren-Bao

2014-01-01

Central spin decoherence caused by nuclear spin baths is often a critical issue in various quantum computing schemes, and it has also been used for sensing single-nuclear spins. Recent theoretical studies suggest that central spin decoherence can act as a probe of many-body physics in spin baths; however, identification and detection of many-body correlations of nuclear spins in nanoscale systems are highly challenging. Here, taking a phosphorus donor electron spin in a 29Si nuclear spin bath as our model system, we discover both theoretically and experimentally that many-body correlations in nanoscale nuclear spin baths produce identifiable signatures in decoherence of the central spin under multiple-pulse dynamical decoupling control. We demonstrate that under control by an odd or even number of pulses, the central spin decoherence is principally caused by second- or fourth-order nuclear spin correlations, respectively. This study marks an important step toward studying many-body physics using spin qubits. PMID:25205440

Advanced driver assistance system: Road sign identification using VIAPIX system and a correlation technique

NASA Astrophysics Data System (ADS)

Ouerhani, Y.; Alfalou, A.; Desthieux, M.; Brosseau, C.

2017-02-01

We present a three-step approach based on the commercial VIAPIX® module for road traffic sign recognition and identification. Firstly, detection in a scene of all objects having characteristics of traffic signs is performed. This is followed by a first-level recognition based on correlation which consists in making a comparison between each detected object with a set of reference images of a database. Finally, a second level of identification allows us to confirm or correct the previous identification. In this study, we perform a correlation-based analysis by combining and adapting the Vander Lugt correlator with the nonlinear joint transformation correlator (JTC). Of particular significance, this approach permits to make a reliable decision on road traffic sign identification. We further discuss a robust scheme allowing us to track a detected road traffic sign in a video sequence for the purpose of increasing the decision performance of our system. This approach can have broad practical applications in the maintenance and rehabilitation of transportation infrastructure, or for drive assistance.

Generalized-active-space pair-density functional theory: an efficient method to study large, strongly correlated, conjugated systems

DOE PAGES

Ghosh, Soumen; Cramer, Christopher J.; Truhlar, Donald G.; ...

2017-01-19

Predicting ground- and excited-state properties of open-shell organic molecules by electronic structure theory can be challenging because an accurate treatment has to correctly describe both static and dynamic electron correlation. Strongly correlated systems, i.e., systems with near-degeneracy correlation effects, are particularly troublesome. Multiconfigurational wave function methods based on an active space are adequate in principle, but it is impractical to capture most of the dynamic correlation in these methods for systems characterized by many active electrons. Here, we recently developed a new method called multiconfiguration pair-density functional theory (MC-PDFT), that combines the advantages of wave function theory and density functionalmore » theory to provide a more practical treatment of strongly correlated systems. Here we present calculations of the singlet–triplet gaps in oligoacenes ranging from naphthalene to dodecacene. Calculations were performed for unprecedently large orbitally optimized active spaces of 50 electrons in 50 orbitals, and we test a range of active spaces and active space partitions, including four kinds of frontier orbital partitions. We show that MC-PDFT can predict the singlet–triplet splittings for oligoacenes consistent with the best available and much more expensive methods, and indeed MC-PDFT may constitute the benchmark against which those other models should be compared, given the absence of experimental data.« less

Generalized-active-space pair-density functional theory: an efficient method to study large, strongly correlated, conjugated systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghosh, Soumen; Cramer, Christopher J.; Truhlar, Donald G.

Predicting ground- and excited-state properties of open-shell organic molecules by electronic structure theory can be challenging because an accurate treatment has to correctly describe both static and dynamic electron correlation. Strongly correlated systems, i.e., systems with near-degeneracy correlation effects, are particularly troublesome. Multiconfigurational wave function methods based on an active space are adequate in principle, but it is impractical to capture most of the dynamic correlation in these methods for systems characterized by many active electrons. Here, we recently developed a new method called multiconfiguration pair-density functional theory (MC-PDFT), that combines the advantages of wave function theory and density functionalmore » theory to provide a more practical treatment of strongly correlated systems. Here we present calculations of the singlet–triplet gaps in oligoacenes ranging from naphthalene to dodecacene. Calculations were performed for unprecedently large orbitally optimized active spaces of 50 electrons in 50 orbitals, and we test a range of active spaces and active space partitions, including four kinds of frontier orbital partitions. We show that MC-PDFT can predict the singlet–triplet splittings for oligoacenes consistent with the best available and much more expensive methods, and indeed MC-PDFT may constitute the benchmark against which those other models should be compared, given the absence of experimental data.« less

Exposure assessment in epidemiologic studies of adverse pregnancy outcomes and disinfection byproducts.

PubMed

King, Will D; Dodds, Linda; Armson, B Anthony; Allen, Alexander C; Fell, Deshayne B; Nimrod, Carl

2004-11-01

A major challenge in studies that examine the association between disinfection byproducts in drinking water and pregnancy outcomes is the accurate representation of a subject's exposure. We used household water samples and questionnaire information on water-use behavior to examine several aspects of exposure assessment: (i) the distribution and correlation of specific disinfection byproducts, (ii) spatial distribution system and temporal variation in byproduct levels, and (iii) the contribution of individual water-use behavior. The level of specific trihalomethanes (THMs) and haloacetic acids (HAAs) was determined for 360 household water samples in Eastern Ontario and Nova Scotia. Subjects were interviewed regarding tap water ingestion and showering and bathing practices. In both provinces, total THMs correlated highly with chloroform (correlation coefficient (r) >0.95) and less so with total HAAs (r = 0.74 in Nova Scotia and r = 0.52 in Ontario). The correlation between total THMs and bromodichloromethane was high in Nova Scotia (r = 0.63), but low in Ontario (r = 0.26). The correlation was between THM level in individual household samples, and the mean THM level during the same time period from several distribution system samples was 0.63, while a higher correlation in THM level was observed for samples taken at the same location 1 year apart (r = 0.87). A correlation of 0.73 was found between household THM level and a total exposure measure incorporating ingestion, showering, and bathing behaviors. These results point to the importance of: measurement of different classes of byproducts; household rather than distribution system sampling; and, incorporation of subject behaviors in exposure assessment in epidemiologic studies of disinfection byproducts and adverse pregnancy outcomes.

ON THE SPIN CORRELATIONS OF MUONS AND TAU LEPTONS GENERATED IN THE ANNIHILATION PROCESSES e+e- → μ+μ-, e+e- → τ+τ-

NASA Astrophysics Data System (ADS)

Lyuboshitz, Valery V.; Lyuboshitz, Vladimir L.

2014-12-01

Using the technique of helicity amplitudes, the electromagnetic process e+e- → μ+μ-(τ+τ-) is theoretically studied in the one-photon approximation. The structure of the triplet states of the final (μ+μ-) system is analyzed. It is shown that in the case of unpolarized electron and positron the final muons are also unpolarized, but their spins are strongly correlated. Explicit expressions for the components of the correlation tensor of the (μ+μ-) system are derived. The formula for the angular correlation at the decays of final muons μ+ and μ- is obtained. It is demonstrated that spin correlations of muons in the considered process have the purely quantum character, since one of the Bell-type incoherence inequalities for the correlation tensor components is always violated.

Multivariate η-μ fading distribution with arbitrary correlation model

NASA Astrophysics Data System (ADS)

Ghareeb, Ibrahim; Atiani, Amani

2018-03-01

An extensive analysis for the multivariate ? distribution with arbitrary correlation is presented, where novel analytical expressions for the multivariate probability density function, cumulative distribution function and moment generating function (MGF) of arbitrarily correlated and not necessarily identically distributed ? power random variables are derived. Also, this paper provides exact-form expression for the MGF of the instantaneous signal-to-noise ratio at the combiner output in a diversity reception system with maximal-ratio combining and post-detection equal-gain combining operating in slow frequency nonselective arbitrarily correlated not necessarily identically distributed ?-fading channels. The average bit error probability of differentially detected quadrature phase shift keying signals with post-detection diversity reception system over arbitrarily correlated and not necessarily identical fading parameters ?-fading channels is determined by using the MGF-based approach. The effect of fading correlation between diversity branches, fading severity parameters and diversity level is studied.

Business cycles' correlation and systemic risk of the Japanese supplier-customer network.

PubMed

Krichene, Hazem; Chakraborty, Abhijit; Inoue, Hiroyasu; Fujiwara, Yoshi

2017-01-01

This work aims to study and explain the business cycle correlations of the Japanese production network. We consider the supplier-customer network, which is a directed network representing the trading links between Japanese firms (links from suppliers to customers). The community structure of this network is determined by applying the Infomap algorithm. Each community is defined by its GDP and its associated business cycle. Business cycle correlations between communities are estimated based on copula theory. Then, based on firms' attributes and network topology, these correlations are explained through linear econometric models. The results show strong evidence of business cycle correlations in the Japanese production network. A significant systemic risk is found for high negative or positive shocks. These correlations are explained mainly by the sector and by geographic similarities. Moreover, our results highlight the higher vulnerability of small communities and small firms, which is explained by the disassortative mixing of the production network.

Business cycles’ correlation and systemic risk of the Japanese supplier-customer network

PubMed Central

Chakraborty, Abhijit; Inoue, Hiroyasu; Fujiwara, Yoshi

2017-01-01

This work aims to study and explain the business cycle correlations of the Japanese production network. We consider the supplier-customer network, which is a directed network representing the trading links between Japanese firms (links from suppliers to customers). The community structure of this network is determined by applying the Infomap algorithm. Each community is defined by its GDP and its associated business cycle. Business cycle correlations between communities are estimated based on copula theory. Then, based on firms’ attributes and network topology, these correlations are explained through linear econometric models. The results show strong evidence of business cycle correlations in the Japanese production network. A significant systemic risk is found for high negative or positive shocks. These correlations are explained mainly by the sector and by geographic similarities. Moreover, our results highlight the higher vulnerability of small communities and small firms, which is explained by the disassortative mixing of the production network. PMID:29059233

Heat flux and quantum correlations in dissipative cascaded systems

NASA Astrophysics Data System (ADS)

Lorenzo, Salvatore; Farace, Alessandro; Ciccarello, Francesco; Palma, G. Massimo; Giovannetti, Vittorio

2015-02-01

We study the dynamics of heat flux in the thermalization process of a pair of identical quantum systems that interact dissipatively with a reservoir in a cascaded fashion. Despite that the open dynamics of the bipartite system S is globally Lindbladian, one of the subsystems "sees" the reservoir in a state modified by the interaction with the other subsystem and hence it undergoes a non-Markovian dynamics. As a consequence, the heat flow exhibits a nonexponential time behavior which can greatly deviate from the case where each party is independently coupled to the reservoir. We investigate both thermal and correlated initial states of S and show that the presence of correlations at the beginning can considerably affect the heat-flux rate. We carry out our study in two paradigmatic cases—a pair of harmonic oscillators with a reservoir of bosonic modes and two qubits with a reservoir of fermionic modes—and compare the corresponding behaviors. In the case of qubits and for initial thermal states, we find that the trace distance discord is at any time interpretable as the correlated contribution to the total heat flux.

[Occlusion and posture: is there evidence of correlation?].

PubMed

Michelotti, A; Manzo, P; Farella, M; Martina, R

1999-11-01

The observation that the masticatory system and the postural body regulating system are anatomically and functionally related, has led to postulate several hypotheses of correlation between occlusal and postural disturbances. In the last decade, these arguments have gained a great social impact, also because they have been broadly spread by the mass-media. As a consequence, there has been a growing number of patients seeking concomitant occlusal and postural treatments. The aim of this study was to review critically the current evidence of correlation between the two systems; this in order to address clinical issues for the management of patients. Methodology of the studies reviewed has been evaluated according to the criteria suggested by Storey and Rugh 20 rif. Although there are some evidences of correlation between occlusion and posture, this appears limited to the cranio-cervical tract of the column and tends to disappear when descending in cranio-caudal direction. On the basis of this review of the literature, it's not advisable to treat postural imbalance by means of occlusal treatment or vice versa, particularly if the therapeutic modalities are irreversible.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tokár, K.; Derian, R.; Mitas, L.

Using explicitly correlated fixed-node quantum Monte Carlo and density functional theory (DFT) methods, we study electronic properties, ground-state multiplets, ionization potentials, electron affinities, and low-energy fragmentation channels of charged half-sandwich and multidecker vanadium-benzene systems with up to 3 vanadium atoms, including both anions and cations. It is shown that, particularly in anions, electronic correlations play a crucial role; these effects are not systematically captured with any commonly used DFT functionals such as gradient corrected, hybrids, and range-separated hybrids. On the other hand, tightly bound cations can be described qualitatively by DFT. A comparison of DFT and quantum Monte Carlo providesmore » an in-depth understanding of the electronic structure and properties of these correlated systems. The calculations also serve as a benchmark study of 3d molecular anions that require a balanced many-body description of correlations at both short- and long-range distances.« less

Correlation-induced superconductivity dynamically stabilized and enhanced by laser irradiation.

PubMed

Ido, Kota; Ohgoe, Takahiro; Imada, Masatoshi

2017-08-01

Studies on out-of-equilibrium dynamics have paved a way to realize a new state of matter. Superconductor-like properties above room temperatures recently suggested to be in copper oxides achieved by selectively exciting vibrational phonon modes by laser have inspired studies on an alternative and general strategy to be pursued for high-temperature superconductivity. We show that the superconductivity can be enhanced by irradiating laser to correlated electron systems owing to two mechanisms: First, the effective attractive interaction of carriers is enhanced by the dynamical localization mechanism, which drives the system into strong coupling regions. Second, the irradiation allows reaching uniform and enhanced superconductivity dynamically stabilized without deteriorating into equilibrium inhomogeneities that suppress superconductivity. The dynamical superconductivity is subject to the Higgs oscillations during and after the irradiation. Our finding sheds light on a way to enhance superconductivity that is inaccessible in equilibrium in strongly correlated electron systems.

Practices in public health finance: an investigation of jurisdiction funding patterns and performance.

PubMed

Honoré, Peggy A; Simoes, Eduardo J; Jones, Walter J; Moonesinghe, Ramal

2004-01-01

A field of study for public health finance has never been adequately developed. Consequently, very little is known about the relationships, types, and amount of finances that fund the public health system in America. This research was undertaken to build on the sparse knowledge of public health finance by examining the value of performance measurement systems to financial analysis. A correlational study was conducted to examine the associations between public health system performance of the 10 essential public health services and funding patterns of 50 local health departments in a large state. The specific objectives were to investigate if different levels and types of revenues, expenditures, and other demographic variables in a jurisdiction are correlated to performance. Pearson correlation analysis did not conclusively show strong associations; however, statistically significant positive associations primarily between higher levels of performance and jurisdiction taxes per capita were found.

Phenotypic selection in natural populations: what limits directional selection?

PubMed

Kingsolver, Joel G; Diamond, Sarah E

2011-03-01

Studies of phenotypic selection document directional selection in many natural populations. What factors reduce total directional selection and the cumulative evolutionary responses to selection? We combine two data sets for phenotypic selection, representing more than 4,600 distinct estimates of selection from 143 studies, to evaluate the potential roles of fitness trade-offs, indirect (correlated) selection, temporally varying selection, and stabilizing selection for reducing net directional selection and cumulative responses to selection. We detected little evidence that trade-offs among different fitness components reduced total directional selection in most study systems. Comparisons of selection gradients and selection differentials suggest that correlated selection frequently reduced total selection on size but not on other types of traits. The direction of selection on a trait often changes over time in many temporally replicated studies, but these fluctuations have limited impact in reducing cumulative directional selection in most study systems. Analyses of quadratic selection gradients indicated stabilizing selection on body size in at least some studies but provided little evidence that stabilizing selection is more common than disruptive selection for most traits or study systems. Our analyses provide little evidence that fitness trade-offs, correlated selection, or stabilizing selection strongly constrains the directional selection reported for most quantitative traits.

Brain Correlates of Stuttering and Syllable Production: Gender Comparison and Replication.

ERIC Educational Resources Information Center

Ingham, Roger J.; Fox, Peter T.; Ingham, Janis C.; Xiong, Jinhu; Zamarripa, Frank; Hardies, L. Jean; Lancaster, Jack L.

2004-01-01

This article reports a gender replication study of the P. T. Fox et a. (2000) performance correlation analysis of neural systems that distinguish between normal and stuttered speech in adult males. Positron-emission tomographic (PET) images of cerebral blood flow (CBF) were correlated with speech behavior scores obtained during PET imaging for 10…

Validation study of an electronic method of condensed outcomes tools reporting in orthopaedics.

PubMed

Farr, Jack; Verma, Nikhil; Cole, Brian J

2013-12-01

Patient-reported outcomes (PRO) instruments are a vital source of data for evaluating the efficacy of medical treatments. Historically, outcomes instruments have been designed, validated, and implemented as paper-based questionnaires. The collection of paper-based outcomes information may result in patients becoming fatigued as they respond to redundant questions. This problem is exacerbated when multiple PRO measures are provided to a single patient. In addition, the management and analysis of data collected in paper format involves labor-intensive processes to score and render the data analyzable. Computer-based outcomes systems have the potential to mitigate these problems by reformatting multiple outcomes tools into a single, user-friendly tool.The study aimed to determine whether the electronic outcomes system presented produces results comparable with the test-retest correlations reported for the corresponding orthopedic paper-based outcomes instruments.The study is designed as a crossover study based on consecutive orthopaedic patients arriving at one of two designated orthopedic knee clinics.Patients were assigned to complete either a paper or a computer-administered questionnaire based on a similar set of questions (Knee injury and Osteoarthritis Outcome Score, International Knee Documentation Committee form, 36-Item Short Form survey, version 1, Lysholm Knee Scoring Scale). Each patient completed the same surveys using the other instrument, so that all patients had completed both paper and electronic versions. Correlations between the results from the two modes were studied and compared with test-retest data from the original validation studies.The original validation studies established test-retest reliability by computing correlation coefficients for two administrations of the paper instrument. Those correlation coefficients were all in the range of 0.7 to 0.9, which was deemed satisfactory. The present study computed correlation coefficients between the paper and electronic modes of administration. These correlation coefficients demonstrated similar results with an overall value of 0.86.On the basis of the correlation coefficients, the electronic application of commonly used knee outcome scores compare variably to the traditional paper variants with a high rate of test-retest correlation. This equivalence supports the use of the condensed electronic outcomes system and validates comparison of scores between electronic and paper modes. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Systemic risk and causality dynamics of the world international shipping market

NASA Astrophysics Data System (ADS)

Zhang, Xin; Podobnik, Boris; Kenett, Dror Y.; Eugene Stanley, H.

2014-12-01

Various studies have reported that many economic systems have been exhibiting an increase in the correlation between different market sectors, a factor that exacerbates the level of systemic risk. We measure this systemic risk of three major world shipping markets, (i) the new ship market, (ii) the second-hand ship market, and (iii) the freight market, as well as the shipping stock market. Based on correlation networks during three time periods, that prior to the financial crisis, during the crisis, and after the crisis, minimal spanning trees (MSTs) and hierarchical trees (HTs) both exhibit complex dynamics, i.e., different market sectors tend to be more closely linked during financial crisis. Brownian distance correlation and Granger causality test both can be used to explore the directional interconnectedness of market sectors, while Brownian distance correlation captures more dependent relationships, which are not observed in the Granger causality test. These two measures can also identify and quantify market regression periods, implying that they contain predictive power for the current crisis.

Pion correlations in relativistic heavy ion collisions at Heavy Ion Spectrometer Systems (HISS)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Christie, W.B. Jr.

This thesis contains the setup, analysis and results of experiment E684H Multi-Pion Correlations in Relativistic Heavy Ion Collisions''. The goals of the original proposal were: (1) To initiate the use of the HISS facility in the study of central Relativistic Heavy Ion Collisions (RHIC). (2) To perform a second generation experiment for the detailed study of the pion source in RHIC. The first generation experiments, implied by the second goal above, refer to pion correlation studies which the Riverside group had performed at the LBL streamer chamber. The major advantage offered by moving the pion correlation studies to HISS ismore » that, being an electronic detector system, as opposed to the Streamer Chamber which is a visual detector, one can greatly increase the statistics for a study of this sort. An additional advantage is that once one has written the necessary detector and physics analysis code to do a particular type of study, the study may be extended to investigate the systematics, with much less effort and in a relatively short time. This paper discusses the Physics motivation for this experiment, the experimental setup and detectors used, the pion correlation analysis, the results, and the conclusions possible future directions for pion studies at HISS. If one is not interested in all the details of the experiment, I believe that by reading the sections on intensity interferometry, the section the fitting of the correlation function and the systematic corrections applied, and the results section, one will get a fairly complete synopsis of the experiment.« less

Correlation between National Influenza Surveillance Data and Google Trends in South Korea

PubMed Central

Jo, Min Woo; Shin, Soo-Yong; Lee, Jae Ho; Ryoo, Seoung Mok; Kim, Won Young; Seo, Dong-Woo

2013-01-01

Background In South Korea, there is currently no syndromic surveillance system using internet search data, including Google Flu Trends. The purpose of this study was to investigate the correlation between national influenza surveillance data and Google Trends in South Korea. Methods Our study was based on a publicly available search engine database, Google Trends, using 12 influenza-related queries, from September 9, 2007 to September 8, 2012. National surveillance data were obtained from the Korea Centers for Disease Control and Prevention (KCDC) influenza-like illness (ILI) and virologic surveillance system. Pearson's correlation coefficients were calculated to compare the national surveillance and the Google Trends data for the overall period and for 5 influenza seasons. Results The correlation coefficient between the KCDC ILI and virologic surveillance data was 0.72 (p<0.05). The highest correlation was between the Google Trends query of H1N1 and the ILI data, with a correlation coefficient of 0.53 (p<0.05), for the overall study period. When compared with the KCDC virologic data, the Google Trends query of bird flu had the highest correlation with a correlation coefficient of 0.93 (p<0.05) in the 2010-11 season. The following queries showed a statistically significant correlation coefficient compared with ILI data for three consecutive seasons: Tamiflu (r = 0.59, 0.86, 0.90, p<0.05), new flu (r = 0.64, 0.43, 0.70, p<0.05) and flu (r = 0.68, 0.43, 0.77, p<0.05). Conclusions In our study, we found that the Google Trends for certain queries using the survey on influenza correlated with national surveillance data in South Korea. The results of this study showed that Google Trends in the Korean language can be used as complementary data for influenza surveillance but was insufficient for the use of predictive models, such as Google Flu Trends. PMID:24339927

Correlation between national influenza surveillance data and google trends in South Korea.

PubMed

Cho, Sungjin; Sohn, Chang Hwan; Jo, Min Woo; Shin, Soo-Yong; Lee, Jae Ho; Ryoo, Seoung Mok; Kim, Won Young; Seo, Dong-Woo

2013-01-01

In South Korea, there is currently no syndromic surveillance system using internet search data, including Google Flu Trends. The purpose of this study was to investigate the correlation between national influenza surveillance data and Google Trends in South Korea. Our study was based on a publicly available search engine database, Google Trends, using 12 influenza-related queries, from September 9, 2007 to September 8, 2012. National surveillance data were obtained from the Korea Centers for Disease Control and Prevention (KCDC) influenza-like illness (ILI) and virologic surveillance system. Pearson's correlation coefficients were calculated to compare the national surveillance and the Google Trends data for the overall period and for 5 influenza seasons. The correlation coefficient between the KCDC ILI and virologic surveillance data was 0.72 (p<0.05). The highest correlation was between the Google Trends query of H1N1 and the ILI data, with a correlation coefficient of 0.53 (p<0.05), for the overall study period. When compared with the KCDC virologic data, the Google Trends query of bird flu had the highest correlation with a correlation coefficient of 0.93 (p<0.05) in the 2010-11 season. The following queries showed a statistically significant correlation coefficient compared with ILI data for three consecutive seasons: Tamiflu (r = 0.59, 0.86, 0.90, p<0.05), new flu (r = 0.64, 0.43, 0.70, p<0.05) and flu (r = 0.68, 0.43, 0.77, p<0.05). In our study, we found that the Google Trends for certain queries using the survey on influenza correlated with national surveillance data in South Korea. The results of this study showed that Google Trends in the Korean language can be used as complementary data for influenza surveillance but was insufficient for the use of predictive models, such as Google Flu Trends.

Method to study complex systems of mesons in lattice QCD

DOE PAGES

Detmold, William; Savage, Martin J.

2010-07-30

Correlation functions involving many hadrons allow finite density systems to be explored with Lattice QCD. Recently, systems with up to 12more » $$\\pi^+$$'s or $K^+$'s have been studied to determine the the $3$-$$\\pi^+$$ and $3$-$K^+$ interactions and the corresponding chemical potential has been determined as a function of density in each case. We derive recursion relations between correlation functions that allow us to extend this work to systems of arbitrary numbers of mesons and to systems containing arbitrary different types of mesons such as $$\\pi^+$$'s, $K^+$'s, $D^0$'s and $B^+$'s. These relations allow for the study of finite-density systems in arbitrary volumes, and the study of high-density systems. Systems comprised of up to N=12 m mesons can be explored with Lattice QCD calculations utilizing $m$ different sources for the quark propagators. As the recursion relations require only a small, N-independent, number of operations to derive the N+1 meson contractions from the N meson contractions, they are compuationally feasible.« less

The thermoelectric properties of strongly correlated systems

NASA Astrophysics Data System (ADS)

Cai, Jianwei

Strongly correlated systems are among the most interesting and complicated systems in physics. Large Seebeck coefficients are found in some of these systems, which highlight the possibility for thermoelectric applications. In this thesis, we study the thermoelectric properties of these strongly correlated systems with various methods. We derived analytic formulas for the resistivity and Seebeck coefficient of the periodic Anderson model based on the dynamic mean field theory. These formulas were possible as the self energy of the single impurity Anderson model could be given by an analytic ansatz derived from experiments and numerical calculations instead of complicated numerical calculations. The results show good agreement with the experimental data of rare-earth compound in a restricted temperature range. These formulas help to understand the properties of periodic Anderson model. Based on the study of rare-earth compounds, we proposed a design for the thermoelectric meta-material. This manmade material is made of quantum dots linked by conducting linkers. The quantum dots act as the rare-earth atoms with heavier mass. We set up a model similar to the periodic Anderson model for this new material. The new model was studied with the perturbation theory for energy bands. The dynamic mean field theory with numerical renormalization group as the impurity solver was used to study the transport properties. With these studies, we confirmed the improved thermoelectric properties of the designed material.

Heat transfer in the coolant channel of a heat-exchanger system based on fluctuation theories

DOE Office of Scientific and Technical Information (OSTI.GOV)

Diaz-Guilera, A.; Rodriguez, M.A.; Rubi, J.M.

1988-11-01

We present a model to study the heat transfer in the coolant channel of a heat-exchanger system. Such a model introduces thermal fluctuations as well as external noises due to different mechanisms of heat interchange. A unified treatment of both kinds of noise is carried out. The stationary mean value of the channel temperature is studied, obtaining effective transport coefficients which affect the stability of the system. The effects of the different noises are visualized in a correlation length obtained from the temperature correlation function. The model has practical implications in the field of nuclear-reactor noise theory.

Design of an Eye Limiting Resolution Visual System Using Commercial-Off-the-Shelf Equipment

NASA Technical Reports Server (NTRS)

Sweet, Barbara T.; Giovannetti, Dean P.

2008-01-01

A feasibility study was conducted to determine if a flight simulator with an eye-limiting resolution out-the-window (OTW) visual system could be built using commercial off-the-shelf (COTS) technology and used to evaluate the visual performance of Air Force pilots in an operations context. Results of this study demonstrate that an eye limiting OTW visual system can be built using COTS technology. Further, a series of operationally-based tasks linked to clinical vision tests can be used within the synthetic environment to demonstrate a correlation and quantify the level of correlation between vision and operational aviation performance.

Behavioral Actions of Alcohol: Phenotypic Relations from Multivariate Analysis of Mutant Mouse Data

PubMed Central

Blednov, Yuri A.; Mayfield, R. Dayne; Belknap, John; Harris, R. Adron

2012-01-01

Behavioral studies of genetically diverse mice have proven powerful for determining relationships between phenotypes and have been widely used in alcohol research. Most of these studies rely on naturally occurring genetic polymorphisms among inbred strains and selected lines. Another approach is to introduce variation by engineering single gene mutations in mice. We have tested 37 different mutant mice and their wild type controls for a variety (31) of behaviors and have mined this dataset by K-means clustering and analysis of correlations. We found a correlation between a stress-related response (activity in a novel environment) and alcohol consumption and preference for saccharin. We confirmed several relationships detected in earlier genetic studies including positive correlation of alcohol consumption with saccharin consumption, and negative correlations with conditioned taste aversion and alcohol withdrawal severity. Introduction of single gene mutations either eliminated or greatly diminished these correlations. The three tests of alcohol consumption used (continuous two bottle choice, and two limited access tests: Drinking In the Dark and Sustained High Alcohol Consumption) share a relationship with saccharin consumption, but differ from each other in their correlation networks. We suggest that alcohol consumption is controlled by multiple physiological systems where single gene mutations can disrupt the networks of such systems. PMID:22405477

A level A in vitro/in vivo correlation in fasted and fed states using different methods: applied to solid immediate release oral dosage form.

PubMed

Souliman, Sabah; Blanquet, Stéphanie; Beyssac, Eric; Cardot, Jean-Michel

2006-01-01

The first purpose of this study was to simulate the impact of food intake on drug release and absorption in vivo using a novel in vitro system which mimics the gastro-intestinal (GI) tract in man. The drug studied was acetaminophen in the form of immediate release (IR) tablets. The second purpose was to establish a level A in vitro/in vivo correlation that could predict the bioavailability of a drug instead of using difficult, time-consuming and expensive in vivo bioequivalence studies. The artificial digestive system was used to estimate the availability of acetaminophen IR tablets for absorption in fasted and fed states. The same study was performed in vivo under similar conditions. A comparison study was carried out between the classical and the novel methods to estimate the efficacy of the new in vitro system to simulate the influence of food on drug release and absorption in vivo. A level A in vitro/in vivo correlation was established with a correlation coefficient of 0.9128 and 0.9984 in the fasted and fed states, respectively. Compared to USP II method, the novel in vitro model demonstrated a high level of efficacy in mimicking the behaviour of acetaminophen IR tablets in vivo in fasted and fed states.

A non-Hermitian analysis of strongly correlated quantum systems

NASA Astrophysics Data System (ADS)

Nakamura, Yuichi; Hatano, Naomichi

2006-03-01

We study a non-Hermitian generalization of strongly correlated quantum systems in which the transfer energy of electrons is asymmetric. Hatano and Nelson[1] applied this technique to non-interacting random electron systems. They related a non-Hermitian critical point to the inverse localization length of the Hermitian systems. We here conjecture that we can obtain in the same way the correlation length of Hermitian interacting non-random systems[2]. We show for the Hubbard model and the antiferromagnetic XXZ model in one dimension that the non-Hermitian critical point of the ground state, where the energy gap vanishes, is equal to the inverse correlation length. We also show that the conjecture is consistent with numerical results for S=1/2 frustrated quantum spin chains with the nearest- and next-nearest-neighbor interactions including the Majumdar-Ghosh model[3]. [1] N. Hatano and D. R. Nelson, PRL 77 (1996) 570; PRB 56 (1997) 8651. [2] Y. Nakamura and N. Hatano, Physica B, accepted. [3] C. K. Majumdar and D. K. Ghosh, J. Phys. C3 (1970) 911; J. Math. Phys. 10 (1969) 1388, 1399.

A United Effort for Crystal Growth, Neutron Scattering, and X-ray Scattering Studies of Novel Correlated Electron Materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Young S.

2015-02-12

The research accomplishments during the award involved experimental studies of correlated electron systems and quantum magnetism. The techniques of crystal growth, neutron scattering, x-ray scattering, and thermodynamic & transport measurements were employed, and graduate students and postdoctoral research associates were trained in these techniques.

In vitro-in vivo correlation strategy applied to an immediate-release solid oral dosage form with a biopharmaceutical classification system IV compound case study.

PubMed

Bredael, Gerard M; Bowers, Niya; Boulineau, Fabien; Hahn, David

2014-07-01

The ability to predict in vivo response of an oral dosage form based on an in vitro technique has been a sought after goal of the pharmaceutical scientist. Dissolution testing that demonstrates discrimination to various critical formulations or process attributes provides a sensitive quality check that may be representative or may be overpredictive of potential in vivo changes. Dissolution methodology with an established in vitro-in vivo relationship or correlation may provide the desired in vivo predictability. To establish this in vitro-in vivo link, a clinical study must be performed. In this article, recommendations are given in the selection of batches for the clinical study followed by potential outcome scenarios. The investigation of a Level C in vitro-in vivo correlation (IVIVC), which is the most common correlation for immediate-release oral dosage forms, is presented. Lastly, an IVIVC case study involving a biopharmaceutical classification system class IV compound is presented encompassing this strategy and techniques. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

Effect of resource constraints on intersimilar coupled networks.

PubMed

Shai, S; Dobson, S

2012-12-01

Most real-world networks do not live in isolation but are often coupled together within a larger system. Recent studies have shown that intersimilarity between coupled networks increases the connectivity of the overall system. However, unlike connected nodes in a single network, coupled nodes often share resources, like time, energy, and memory, which can impede flow processes through contention when intersimilarly coupled. We study a model of a constrained susceptible-infected-recovered (SIR) process on a system consisting of two random networks sharing the same set of nodes, where nodes are limited to interact with (and therefore infect) a maximum number of neighbors at each epidemic time step. We obtain that, in agreement with previous studies, when no limit exists (regular SIR model), positively correlated (intersimilar) coupling results in a lower epidemic threshold than negatively correlated (interdissimilar) coupling. However, in the case of the constrained SIR model, the obtained epidemic threshold is lower with negatively correlated coupling. The latter finding differentiates our work from previous studies and provides another step towards revealing the qualitative differences between single and coupled networks.

Effect of resource constraints on intersimilar coupled networks

NASA Astrophysics Data System (ADS)

Shai, S.; Dobson, S.

2012-12-01

Most real-world networks do not live in isolation but are often coupled together within a larger system. Recent studies have shown that intersimilarity between coupled networks increases the connectivity of the overall system. However, unlike connected nodes in a single network, coupled nodes often share resources, like time, energy, and memory, which can impede flow processes through contention when intersimilarly coupled. We study a model of a constrained susceptible-infected-recovered (SIR) process on a system consisting of two random networks sharing the same set of nodes, where nodes are limited to interact with (and therefore infect) a maximum number of neighbors at each epidemic time step. We obtain that, in agreement with previous studies, when no limit exists (regular SIR model), positively correlated (intersimilar) coupling results in a lower epidemic threshold than negatively correlated (interdissimilar) coupling. However, in the case of the constrained SIR model, the obtained epidemic threshold is lower with negatively correlated coupling. The latter finding differentiates our work from previous studies and provides another step towards revealing the qualitative differences between single and coupled networks.

[Meaning in life and mental health: personal meaning systems of psychotherapists and psychotherapy patients].

PubMed

Löffler, Sabine; Knappe, Rainer; Joraschky, Peter; Pöhlmann, Karin

2010-01-01

This study investigated differences in the personal meaning systems of psychotherapists and psychotherapy patients as well as correlations between meaning in life and mental health. We qualitatively assessed the content and structure of the personal meaning systems of 41 psychotherapists and 77 psychotherapy patients. In addition, the participants completed questionnaires measuring meaning in life (LRI-r-d), sense of coherence (SOC-9L), self-esteem (RSES), satisfaction with life (SWLS), self-efficacy (SWK), and depression (BDI). The personal meaning systems of psychotherapists were more complex and coherent compared to psychotherapy patients. In the group of psychotherapy patients, a more elaborate structure of the personal meaning system correlated with the subjective sense of meaning. We were able to confirm correlations between meaning in life and mental health for most of the instances. Psychotherapists had more elaborate and coherent meaning systems than psychotherapy patients. Especially for psychotherapy patients elaborate and coherent meaning systems turned out to be important for mental health.

Spatio-temporal correlations in the Manna model in one, three and five dimensions

NASA Astrophysics Data System (ADS)

Willis, Gary; Pruessner, Gunnar

2018-02-01

Although the paradigm of criticality is centered around spatial correlations and their anomalous scaling, not many studies of self-organized criticality (SOC) focus on spatial correlations. Often, integrated observables, such as avalanche size and duration, are used, not least as to avoid complications due to the unavoidable lack of translational invariance. The present work is a survey of spatio-temporal correlation functions in the Manna Model of SOC, measured numerically in detail in d = 1,3 and 5 dimensions and compared to theoretical results, in particular relating them to “integrated” observables such as avalanche size and duration scaling, that measure them indirectly. Contrary to the notion held by some of SOC models organizing into a critical state by re-arranging their spatial structure avalanche by avalanche, which may be expected to result in large, nontrivial, system-spanning spatial correlations in the quiescent state (between avalanches), correlations of inactive particles in the quiescent state have a small amplitude that does not and cannot increase with the system size, although they display (noisy) power law scaling over a range linear in the system size. Self-organization, however, does take place as the (one-point) density of inactive particles organizes into a particular profile that is asymptotically independent of the driving location, also demonstrated analytically in one dimension. Activity and its correlations, on the other hand, display nontrivial long-ranged spatio-temporal scaling with exponents that can be related to established results, in particular avalanche size and duration exponents. The correlation length and amplitude are set by the system size (confirmed analytically for some observables), as expected in systems displaying finite size scaling. In one dimension, we find some surprising inconsistencies of the dynamical exponent. A (spatially extended) mean field theory (MFT) is recovered, with some corrections, in five dimensions.

Using an intelligent system to aid in tephra layer correlation of the tephra beds of the Mono-Inyo Craters, California

NASA Astrophysics Data System (ADS)

Hanson-Hedgecock, S.; Bursik, M.; Rogova, G.

2008-12-01

We are developing an intelligent system to correlate tephra layers by using the lithologic and geochemical characteristics of field samples, to aid geologists in interpreting eruption patterns in volcanic fields. Understanding the eruption history of a volcanic field from stratigraphic studies is important for forecasting future eruptive behavior and hazards. The intelligent system is used to define groups of tephra source vents and to correlate tephra layers based on a combination of geochemical data and lithostratigraphic characteristics. The tephra beds of the Mono-Inyo Craters, California, are used to test the ability of the intelligent system for tephra layer correlation. The data processing is performed by a suite of both unsupervised and supervised classifiers, built and combined within the framework of the Dempster-Shafer theory of evidence. We have developed algorithms to calculate isopleth maps of thickness, lithic and pumice size that are used in the processing of the lithostratigraphic data. This spatial information is important in the determination of eruption patterns and is used by an evidential nearest neighbor classifier to correlate tephra layers. Integrating a better isopleth approximation function and expert knowledge about stratigraphic order of the tephra layers into the classifier improves the lithostratigraphic correlation from 56% to 87% of layers correctly identified. Geochemical data for defining groups of tephra sources are processed by a suit of fuzzy k-means classifiers. Improved clustering results of geochemical data are achieved by the fusion of individual clustering results with an evidential combination method. The intelligent system aids correlation by showing matches and disparities between data patterns from different outcrops that may have been overlooked. The intelligent system produces a useful recognition result, while dealing with the uncertainty from sparse data and the imprecise description of layer characteristics.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suhara, Tadahiro; Kanada-En'yo, Yoshiko

We investigate the linear-chain structures in highly excited states of {sup 14}C using a generalized molecular-orbital model, by which we incorporate an asymmetric configuration of three {alpha} clusters in the linear-chain states. By applying this model to the {sup 14}C system, we study the {sup 10}Be+{alpha} correlation in the linear-chain state of {sup 14}C. To clarify the origin of the {sup 10}Be+{alpha} correlation in the {sup 14}C linear-chain state, we analyze linear 3 {alpha} and 3{alpha} + n systems in a similar way. We find that a linear 3{alpha} system prefers the asymmetric 2{alpha} + {alpha} configuration, whose origin ismore » the many-body correlation incorporated by the parity projection. This configuration causes an asymmetric mean field for two valence neutrons, which induces the concentration of valence neutron wave functions around the correlating 2{alpha}. A linear-chain structure of {sup 16}C is also discussed.« less

Structure of public transit costs in the presence of multiple serial correlation

DOT National Transportation Integrated Search

1999-12-01

Most studies indicate that public transit systems operate under increasing returns to capital stock utilization and are significantly overcapitalized. Existing flexible form time series analyses, however, fail to correct for serial correlation. In th...

Fabry disease in children: correlation between ocular manifestations, genotype and systemic clinical severity.

PubMed

Allen, L E; Cosgrave, E M; Kersey, J P; Ramaswami, U

2010-12-01

Fabry disease is an X linked lysosomal disorder associated with severe multiorgan failure and premature death. This study aims to determine the prevalence of ophthalmic manifestations in children with the condition and investigate the correlation with genotype and systemic disease severity. The records of 26 children from 18 pedigrees with Fabry disease undergoing regular ophthalmic and systemic examination were reviewed. All pedigrees underwent GLA gene sequencing to determine genotype. Correlations between ocular and systemic phenotype and genotype were investigated. Corneal verticillata occurred in 50% of the children in this study (95% CI, 29% to 79%). Children with ophthalmic manifestations were more likely to have loss-of-function GLA mutations (p=0.003). Retinal vascular tortuosity was seen in seven children (27%), all of whom had systemic symptoms suggestive of autonomic neuropathy, such as diarrhoea and syncope. These symptoms seemed less prevalent in children without retinal vascular changes, although this did not reach statistical significance (p=0.134). Ophthalmic manifestations of Fabry disease are common even in young children with loss-of-function GLA gene mutations. Although the limited sample size possibly prevented statistical significance, systemic symptoms of autonomic neuropathy often coexist with retinal vascular changes and may share the same pathogenesis.

Thermodynamic properties Ar films on the surface of a bundle of carbon nanotubes

NASA Astrophysics Data System (ADS)

Cole, Milton; Gatica, Silvina

2005-03-01

We employ canonical Monte Carlo simulations to explore the properties of an Argon film adsorbed on the external surface of a bundle of carbon nanotubes. The study is concerned primarily with three properties: specific heat, differential heat of adsorption, and Ar-Ar correlation functions. These measurable functions exhibit information about the dependence of film structure on coverage and temperature. Our results are intended to stimulate further experimental studies of this system and analogous systems involving other gases on nanotube bundles. One of the more interesting general results is that the specific heat is typically larger than might have been expected. Particularly remarkable outcome from the correlation function studies include the reduced longitudinal correlations in the groove and striped phases as T rises above 60 K. These results would be amenable to testing by diffraction experiments.

Quantum correlations in non-inertial cavity systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harsij, Zeynab, E-mail: z.harsij@ph.iut.ac.ir; Mirza, Behrouz, E-mail: b.mirza@cc.iut.ac.ir

2016-10-15

Non-inertial cavities are utilized to store and send Quantum Information between mode pairs. A two-cavity system is considered where one is inertial and the other accelerated in a finite time. Maclaurian series are applied to expand the related Bogoliubov coefficients and the problem is treated perturbatively. It is shown that Quantum Discord, which is a measure of quantumness of correlations, is degraded periodically. This is almost in agreement with previous results reached in accelerated systems where increment of acceleration decreases the degree of quantum correlations. As another finding of the study, it is explicitly shown that degradation of Quantum Discordmore » disappears when the state is in a single cavity which is accelerated for a finite time. This feature makes accelerating cavities useful instruments in Quantum Information Theory. - Highlights: • Non-inertial cavities are utilized to store and send information in Quantum Information Theory. • Cavities include boundary conditions which will protect the entanglement once it has been created. • The problem is treated perturbatively and the maclaurian series are applied to expand the related Bogoliubov coefficients. • When two cavities are considered degradation in the degree of quantum correlation happens and it appears periodically. • The interesting issue is when a single cavity is studied and the degradation in quantum correlations disappears.« less

Personal Value Systems of Union Leaders and Corporate Managers: A Comparative Study.

DTIC Science & Technology

LABOR UNIONS, LEADERSHIP ), (*SUPERVISORS, BEHAVIOR), (*PERFORMANCE(HUMAN), ANALOG SYSTEMS), MATHEMATICAL MODELS, CORRELATION TECHNIQUES, ATTITUDES(PSYCHOLOGY), PSYCHOLOGICAL TESTS, PROBABILITY, INDUSTRIAL RELATIONS

Parts and Wholes. An Inquiry into Quantum and Classical Correlations

NASA Astrophysics Data System (ADS)

Seevinck, M. P.

2008-10-01

The primary topic of this dissertation is, firstly, the study of the correlations between outcomes of measurements on the subsystems of a composed system as predicted by a particular physical theory; secondly, the study of what this physical theory predicts for the relationships these subsystems can have to the composed system they are a part of; and thirdly, the comparison of different physical theories with respect to these two aspects. The physical theories investigated and compared are generalized probability theories in a quasi-classical physics framework and non-relativistic quantum theory. The motivation for these enquiries is that a comparison of the relationships between parts and whole as described by each theory, and of the correlations predicted by each theory between separated subsystems yields a fruitful method to investigate what these physical theories say about the world. One then finds, independent of any physical model, relationships and constraints that capture the essential physical assumptions and structural aspects of the theory in question. As such one gains a larger and deeper understanding of the different physical theories under investigation and of what they say about the world. A large part of this dissertation is devoted to understanding different aspects of different kinds of correlations that can exist between the outcomes of measurement on subsystems of a larger system. Four different kinds of correlation have been investigated: local, partially-local, no-signaling and quantum mechanical. Novel characteristics of these correlations have been used to study how they are related and how they can be discerned. The main tool of this investigation has been the usage of Bell-type inequalities that give non-trivial bounds on the strength of the correlations. The study of quantum correlations has also prompted us to study the multi-partite qubit state space with respect to its entanglement and separability characteristics, and the differing strength of the correlations in separable and entangled qubit states. Comparing the different types of correlations has provided us with many new results on the various strengths of the different types of correlation. Because of the generality of the investigation -- we have considered abstract general models, not some specific and particular ones -- these results have strong repercussions for different sorts of physical theories. These repercussions have foundational as well as philosophical impact, notably for the viability of hidden variable theories for quantum mechanics, for the possibility of doing experimental metaphysics, for the question of holism in physical theories, and for the classical vs. quantum dichotomy.

Models of compacted fine-grained soils used as mineral liner for solid waste

NASA Astrophysics Data System (ADS)

Sivrikaya, Osman

2008-02-01

To prevent the leakage of pollutant liquids into groundwater and sublayers, the compacted fine-grained soils are commonly utilized as mineral liners or a sealing system constructed under municipal solid waste and other containment hazardous materials. This study presents the correlation equations of the compaction parameters required for construction of a mineral liner system. The determination of the characteristic compaction parameters, maximum dry unit weight ( γ dmax) and optimum water content ( w opt) requires considerable time and great effort. In this study, empirical models are described and examined to find which of the index properties correlate well with the compaction characteristics for estimating γ dmax and w opt of fine-grained soils at the standard compactive effort. The compaction data are correlated with different combinations of gravel content ( G), sand content ( S), fine-grained content (FC = clay + silt), plasticity index ( I p), liquid limit ( w L) and plastic limit ( w P) by performing multilinear regression (MLR) analyses. The obtained correlations with statistical parameters are presented and compared with the previous studies. It is found that the maximum dry unit weight and optimum water content have a considerably good correlation with plastic limit in comparison with liquid limit and plasticity index.

Applicability of geomechanical classifications for estimation of strength properties in Brazilian rock masses.

PubMed

Santos, Tatiana B; Lana, Milene S; Santos, Allan E M; Silveira, Larissa R C

2017-01-01

Many authors have been proposed several correlation equations between geomechanical classifications and strength parameters. However, these correlation equations have been based in rock masses with different characteristics when compared to Brazilian rock masses. This paper aims to study the applicability of the geomechanical classifications to obtain strength parameters of three Brazilian rock masses. Four classification systems have been used; the Rock Mass Rating (RMR), the Rock Mass Quality (Q), the Geological Strength Index (GSI) and the Rock Mass Index (RMi). A strong rock mass and two soft rock masses with different degrees of weathering located in the cities of Ouro Preto and Mariana, Brazil; were selected for the study. Correlation equations were used to estimate the strength properties of these rock masses. However, such correlations do not always provide compatible results with the rock mass behavior. For the calibration of the strength values obtained through the use of classification systems, ​​stability analyses of failures in these rock masses have been done. After calibration of these parameters, the applicability of the various correlation equations found in the literature have been discussed. According to the results presented in this paper, some of these equations are not suitable for the studied rock masses.

Theoretical study of the NO gamma system

NASA Technical Reports Server (NTRS)

Langhoff, Stephen R.; Bauschlicher, Charles W., Jr.; Partridge, Harry

1988-01-01

A systematic study of the NO gamma system with level of correlation treatment was carried out using large Gaussian basis sets to determine the potential curves for the X2Pi and A2Sigma(+) states of NO. It is shown that the A2Sigma-X2Pi electronic transition moment (gamma system) increases monotonically with decreasing internuclear distance and that the increase in the moment as r decreases is correlated with the increasing degree of diffuse character in the X2Pi state. The results of a study of the X2Pi and A2Sigma(+) dipole moment functions showed that the X2Pi vibrationally averaged dipole moments and the (1-0) and (2-0) vibration-rotation band intensities agree well with experimental data.

Identification of Abnormal System Noise Temperature Patterns in Deep Space Network Antennas Using Neural Network Trained Fuzzy Logic

NASA Technical Reports Server (NTRS)

Lu, Thomas; Pham, Timothy; Liao, Jason

2011-01-01

This paper presents the development of a fuzzy logic function trained by an artificial neural network to classify the system noise temperature (SNT) of antennas in the NASA Deep Space Network (DSN). The SNT data were classified into normal, marginal, and abnormal classes. The irregular SNT pattern was further correlated with link margin and weather data. A reasonably good correlation is detected among high SNT, low link margin and the effect of bad weather; however we also saw some unexpected non-correlations which merit further study in the future.

Anti-correlation and subsector structure in financial systems

NASA Astrophysics Data System (ADS)

Jiang, X. F.; Zheng, B.

2012-02-01

With the random matrix theory, we study the spatial structure of the Chinese stock market, the American stock market and global market indices. After taking into account the signs of the components in the eigenvectors of the cross-correlation matrix, we detect the subsector structure of the financial systems. The positive and negative subsectors are anti-correlated with respect to each other in the corresponding eigenmode. The subsector structure is strong in the Chinese stock market, while somewhat weaker in the American stock market and global market indices. Characteristics of the subsector structures in different markets are revealed.

Study of photon correlation techniques for processing of laser velocimeter signals

NASA Technical Reports Server (NTRS)

Mayo, W. T., Jr.

1977-01-01

The objective was to provide the theory and a system design for a new type of photon counting processor for low level dual scatter laser velocimeter (LV) signals which would be capable of both the first order measurements of mean flow and turbulence intensity and also the second order time statistics: cross correlation auto correlation, and related spectra. A general Poisson process model for low level LV signals and noise which is valid from the photon-resolved regime all the way to the limiting case of nonstationary Gaussian noise was used. Computer simulation algorithms and higher order statistical moment analysis of Poisson processes were derived and applied to the analysis of photon correlation techniques. A system design using a unique dual correlate and subtract frequency discriminator technique is postulated and analyzed. Expectation analysis indicates that the objective measurements are feasible.

Triplet p + ip pairing correlations in the doped Kane-Mele-Hubbard model: A quantum Monte Carlo study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ma, Tianxing; Lin, Hai-Qing; Gubernatis, James E.

2015-09-01

By using the constrained-phase quantum Monte Carlo method, we performed a systematic study of the pairing correlations in the ground state of the doped Kane-Mele-Hubbard model on a honeycomb lattice. We find that pairing correlations with d + id symmetry dominate close to half filling, but pairing correlations with p+ip symmetry dominate as hole doping moves the system below three-quarters filling. We correlate these behaviors of the pairing correlations with the topology of the Fermi surfaces of the non-interacting problem. We also find that the effective pairing correlation is enhanced greatly as the interaction increases, and these superconducting correlations aremore » robust against varying the spin-orbit coupling strength. Finally, our numerical results suggest a possible way to realize spin triplet superconductivity in doped honeycomb-like materials or ultracold atoms in optical traps.« less

Asymmetric correlation matrices: an analysis of financial data

NASA Astrophysics Data System (ADS)

Livan, G.; Rebecchi, L.

2012-06-01

We analyse the spectral properties of correlation matrices between distinct statistical systems. Such matrices are intrinsically non-symmetric, and lend themselves to extend the spectral analyses usually performed on standard Pearson correlation matrices to the realm of complex eigenvalues. We employ some recent random matrix theory results on the average eigenvalue density of this type of matrix to distinguish between noise and non-trivial correlation structures, and we focus on financial data as a case study. Namely, we employ daily prices of stocks belonging to the American and British stock exchanges, and look for the emergence of correlations between two such markets in the eigenvalue spectrum of their non-symmetric correlation matrix. We find several non trivial results when considering time-lagged correlations over short lags, and we corroborate our findings by additionally studying the asymmetric correlation matrix of the principal components of our datasets.

Comparing Occupational Health and Safety Management System Programming with Injury Rates in Poultry Production.

PubMed

Autenrieth, Daniel A; Brazile, William J; Douphrate, David I; Román-Muñiz, Ivette N; Reynolds, Stephen J

2016-01-01

Effective methods to reduce work-related injuries and illnesses in animal production agriculture are sorely needed. One approach that may be helpful for agriculture producers is the adoption of occupational health and safety management systems. In this replication study, the authors compared the injury rates on 32 poultry growing operations with the level of occupational health and safety management system programming at each farm. Overall correlations between injury rates and programming level were determined, as were correlations between individual management system subcomponents to ascertain which parts might be the most useful for poultry producers. It was found that, in general, higher levels of occupational health and safety management system programming were associated with lower rates of workplace injuries and illnesses, and that Management Leadership was the system subcomponent with the strongest correlation. The strength and significance of the observed associations were greater on poultry farms with more complete management system assessments. These findings are similar to those from a previous study of the dairy production industry, suggesting that occupational health and safety management systems may hold promise as a comprehensive way for producers to improve occupational health and safety performance. Further research is needed to determine the effectiveness of such systems to reduce farm work injuries and illnesses. These results are timely given the increasing focus on occupational safety and health management systems.

Correlation effects in superconducting quantum dot systems

NASA Astrophysics Data System (ADS)

Pokorný, Vladislav; Žonda, Martin

2018-05-01

We study the effect of electron correlations on a system consisting of a single-level quantum dot with local Coulomb interaction attached to two superconducting leads. We use the single-impurity Anderson model with BCS superconducting baths to study the interplay between the proximity induced electron pairing and the local Coulomb interaction. We show how to solve the model using the continuous-time hybridization-expansion quantum Monte Carlo method. The results obtained for experimentally relevant parameters are compared with results of self-consistent second order perturbation theory as well as with the numerical renormalization group method.

Association of periodontal disease with systemic health indices in dogs and the systemic response to treatment of periodontal disease.

PubMed

Rawlinson, Jennifer E; Goldstein, Richard E; Reiter, Alexander M; Attwater, Daniel Z; Harvey, Colin E

2011-03-01

To determine whether severity of periodontal disease (PD) was associated with systemic health indices in dogs and whether treatment of PD altered systemic health indices. Prospective cohort study. 38 dogs. Healthy dogs with clinical signs of PD were included in the study. Physical examination, serum biochemical analysis, a CBC, urine evaluation, measurement of serum C-reactive protein (CRP) concentration, and a microalbuminuria test were performed prior to treatment of PD. All tooth roots were scored for gingivitis and attachment loss, and appropriate treatment of PD was performed. Laboratory data were obtained 4 weeks after treatment. The Spearman rank correlation and Wilcoxon signed rank test were used for statistical analysis. Analyses of the correlation of several variables with attachment loss or gingivitis or of differences before and after treatment revealed significant results for several variables. After applying Bonferroni corrections for family-wise error rate, significant rank correlations were found between attachment loss and platelet number (r = 0.54), creatinine concentration (r = -0.49), and the within-dog difference in CRP concentrations before and after treatment (r = 0.40). The BUN concentration was significantly higher after treatment than before treatment. Increasing severity of attachment loss was associated with changes in systemic inflammatory variables and renal indices. A decrease in CRP concentration after treatment was correlated with the severity of PD. The BUN concentration increased significantly after treatment of PD. There is a need for continued research into the systemic impact of PD.

Quantitative X-ray diffraction and fluorescence analysis of paint pigment systems : final report.

DOT National Transportation Integrated Search

1978-01-01

This study attempted to correlate measured X-ray intensities with concentrations of each member of paint pigment systems, thereby establishing calibration curves for the quantitative analyses of such systems.

The Prevalence and Correlates of Involvement in the Criminal Justice System among Youth on the Autism Spectrum

ERIC Educational Resources Information Center

Rava, Julianna; Shattuck, Paul; Rast, Jessica; Roux, Anne

2017-01-01

This study examined the prevalence and correlates of involvement in the criminal justice system among a nationally representative sample of youth with autism. We examined whether youth had been stopped and questioned by police or arrested at 14-15 years old and 21-22 years old. By age 21, approximately 20% of youth with autism had been stopped and…

Characterization of fluid flow by digital correlation of scattered light

NASA Technical Reports Server (NTRS)

Gilbert, John A.; Matthys, Donald R.

1989-01-01

The objective is to produce a physical system suitable for a space environment that can measure fluid velocities in a three-dimensional volume by the development of a particle correlation velocimetry technique. Experimental studies were conducted on a field test cell to demonstrate the suitability and accuracy of digital correlation techniques for measuring two-dimensional fluid flows. This objective was satisfied by: (1) the design of an appropriate illumination and detection system for making velocity measurements within a test cell; (2) the design and construction of a test cell; (3) the preliminary evaluations on fluid and seeding requirements; and (4) the performance of controlled tests using a multiple exposure correlation technique. This presentation is represented by viewgraphs with very little text.

Communication: importance sampling including path correlation in semiclassical initial value representation calculations for time correlation functions.

PubMed

Pan, Feng; Tao, Guohua

2013-03-07

Full semiclassical (SC) initial value representation (IVR) for time correlation functions involves a double phase space average over a set of two phase points, each of which evolves along a classical path. Conventionally, the two initial phase points are sampled independently for all degrees of freedom (DOF) in the Monte Carlo procedure. Here, we present an efficient importance sampling scheme by including the path correlation between the two initial phase points for the bath DOF, which greatly improves the performance of the SC-IVR calculations for large molecular systems. Satisfactory convergence in the study of quantum coherence in vibrational relaxation has been achieved for a benchmark system-bath model with up to 21 DOF.

Nonlinear Analysis on Cross-Correlation of Financial Time Series by Continuum Percolation System

NASA Astrophysics Data System (ADS)

Niu, Hongli; Wang, Jun

We establish a financial price process by continuum percolation system, in which we attribute price fluctuations to the investors’ attitudes towards the financial market, and consider the clusters in continuum percolation as the investors share the same investment opinion. We investigate the cross-correlations in two return time series, and analyze the multifractal behaviors in this relationship. Further, we study the corresponding behaviors for the real stock indexes of SSE and HSI as well as the liquid stocks pair of SPD and PAB by comparison. To quantify the multifractality in cross-correlation relationship, we employ multifractal detrended cross-correlation analysis method to perform an empirical research for the simulation data and the real markets data.

The dominance behavioral system and manic temperament: Motivation for dominance, self-perceptions of power, and socially dominant behaviors

PubMed Central

Johnson, Sheri L.; Carver, Charles S.

2013-01-01

The dominance behavioral system has been conceptualized as a biologically based system comprising motivation to achieve social power and self-perceptions of power. Biological, behavioral, and social correlates of dominance motivation and self-perceived power have been related to a range of psychopathological tendencies. Preliminary evidence suggests that mania and risk for mania (manic temperament) relate to the dominance system. Method Four studies examine whether manic temperament, measured with the Hypomanic Personality Scale (HPS), is related to elevations in dominance motivation, self-perceptions of power, and engagement in socially dominant behavior across multiple measures. In Study 1, the HPS correlated with measures of dominance motivation and the pursuit of extrinsically-oriented ambitions for fame and wealth among 454 undergraduates. In Study 2, the HPS correlated with perceptions of power and extrinsically-oriented lifetime ambitions among 780 undergraduates. In Study 3, the HPS was related to trait-like tendencies to experience hubristic (dominance-related) pride, as well as dominance motivation and pursuit of extrinsically-oriented ambitions. In Study 4, we developed the Socially Dominant Behavior Scale to capture behaviors reflecting high power. The scale correlated highly with the HPS among 514 undergraduates. Limitations The studies rely on self-ratings of manic temperament and dominance constructs, and findings have not yet been generalized to a clinical sample. Conclusions Taken together, results support the hypothesis that manic temperament is related to a focus on achieving social dominance, ambitions related to achieving social recognition, perceptions of having achieved power, tendencies to experience dominance-related pride, and engagement in social behaviors consistent with this elevated sense of power. PMID:22840614

The dominance behavioral system and manic temperament: motivation for dominance, self-perceptions of power, and socially dominant behaviors.

PubMed

Johnson, Sheri L; Carver, Charles S

2012-12-15

The dominance behavioral system has been conceptualized as a biologically based system comprising motivation to achieve social power and self-perceptions of power. Biological, behavioral, and social correlates of dominance motivation and self-perceived power have been related to a range of psychopathological tendencies. Preliminary evidence suggests that mania and risk for mania (manic temperament) relate to the dominance system. Four studies examine whether manic temperament, measured with the Hypomanic Personality Scale (HPS), is related to elevations in dominance motivation, self-perceptions of power, and engagement in socially dominant behavior across multiple measures. In Study 1, the HPS correlated with measures of dominance motivation and the pursuit of extrinsically-oriented ambitions for fame and wealth among 454 undergraduates. In Study 2, the HPS correlated with perceptions of power and extrinsically-oriented lifetime ambitions among 780 undergraduates. In Study 3, the HPS was related to trait-like tendencies to experience hubristic (dominance-related) pride, as well as dominance motivation and pursuit of extrinsically-oriented ambitions. In Study 4, we developed the Socially Dominant Behavior Scale to capture behaviors reflecting high power. The scale correlated highly with the HPS among 514 undergraduates. The studies rely on self-ratings of manic temperament and dominance constructs, and findings have not yet been generalized to a clinical sample. Taken together, results support the hypothesis that manic temperament is related to a focus on achieving social dominance, ambitions related to achieving social recognition, perceptions of having achieved power, tendencies to experience dominance-related pride, and engagement in social behaviors consistent with this elevated sense of power. Copyright © 2012 Elsevier B.V. All rights reserved.

The study and development of the empirical correlations equation of natural convection heat transfer on vertical rectangular sub-channels

NASA Astrophysics Data System (ADS)

Kamajaya, Ketut; Umar, Efrizon; Sudjatmi, K. S.

2012-06-01

This study focused on natural convection heat transfer using a vertical rectangular sub-channel and water as the coolant fluid. To conduct this study has been made pipe heaters are equipped with thermocouples. Each heater is equipped with five thermocouples along the heating pipes. The diameter of each heater is 2.54 cm and 45 cm in length. The distance between the central heating and the pitch is 29.5 cm. Test equipment is equipped with a primary cooling system, a secondary cooling system and a heat exchanger. The purpose of this study is to obtain new empirical correlations equations of the vertical rectangular sub-channel, especially for the natural convection heat transfer within a bundle of vertical cylinders rectangular arrangement sub-channels. The empirical correlation equation can support the thermo-hydraulic analysis of research nuclear reactors that utilize cylindrical fuel rods, and also can be used in designing of baffle-free vertical shell and tube heat exchangers. The results of this study that the empirical correlation equations of natural convection heat transfer coefficients with rectangular arrangement is Nu = 6.3357 (Ra.Dh/x)0.0740.

Elastic constants and dynamics in nematic liquid crystals

NASA Astrophysics Data System (ADS)

Humpert, Anja; Allen, Michael P.

2015-09-01

In this paper, we present molecular dynamics calculations of the Frank elastic constants, and associated time correlation functions, in nematic liquid crystals. We study two variants of the Gay-Berne potential, and use system sizes of half a million molecules, significantly larger than in previous studies of elastic behaviour. Equilibrium orientational fluctuations in reciprocal (k-) space were calculated, to determine the elastic constants by fitting at low |k|; our results indicate that small system size may be a source of inaccuracy in previous work. Furthermore, the dynamics of the Gay-Berne nematic were studied by calculating time correlation functions of components of the order tensor, together with associated components of the velocity field, for a set of wave vectors k. Confirming our earlier work, we found exponential decay for splay and twist correlations, and oscillatory exponential decay for the bend correlation. In this work, we confirm similar behaviour for the corresponding velocity components. In all cases, the decay rates, and oscillation frequencies, were found to be accurately proportional to k2 for small k, as predicted by the equations of nematodynamics. However, the observation of oscillatory bend fluctuations, and corresponding oscillatory shear flow decay, is in contradiction to the usual assumptions appearing in the literature, and in standard texts. We discuss the advantages and drawbacks of using large systems in these calculations.

Contribution to viscosity from the structural relaxation via the atomic scale Green-Kubo stress correlation function.

PubMed

Levashov, V A

2017-11-14

We studied the connection between the structural relaxation and viscosity for a binary model of repulsive particles in the supercooled liquid regime. The used approach is based on the decomposition of the macroscopic Green-Kubo stress correlation function into the correlation functions between the atomic level stresses. Previously we used the approach to study an iron-like single component system of particles. The role of vibrational motion has been addressed through the demonstration of the relationship between viscosity and the shear waves propagating over large distances. In our previous considerations, however, we did not discuss the role of the structural relaxation. Here we suggest that the contribution to viscosity from the structural relaxation can be taken into account through the consideration of the contribution from the atomic stress auto-correlation term only. This conclusion, however, does not mean that only the auto-correlation term represents the contribution to viscosity from the structural relaxation. Previously the role of the structural relaxation for viscosity has been addressed through the considerations of the transitions between inherent structures and within the mode-coupling theory by other authors. In the present work, we study the structural relaxation through the considerations of the parent liquid and the atomic level stress correlations in it. The comparison with the results obtained on the inherent structures also is made. Our current results suggest, as our previous observations, that in the supercooled liquid regime, the vibrational contribution to viscosity extends over the times that are much larger than the Einstein's vibrational period and much larger than the times that it takes for the shear waves to propagate over the model systems. Besides addressing the atomic level shear stress correlations, we also studied correlations between the atomic level pressure elements.

Contribution to viscosity from the structural relaxation via the atomic scale Green-Kubo stress correlation function

NASA Astrophysics Data System (ADS)

Levashov, V. A.

2017-11-01

We studied the connection between the structural relaxation and viscosity for a binary model of repulsive particles in the supercooled liquid regime. The used approach is based on the decomposition of the macroscopic Green-Kubo stress correlation function into the correlation functions between the atomic level stresses. Previously we used the approach to study an iron-like single component system of particles. The role of vibrational motion has been addressed through the demonstration of the relationship between viscosity and the shear waves propagating over large distances. In our previous considerations, however, we did not discuss the role of the structural relaxation. Here we suggest that the contribution to viscosity from the structural relaxation can be taken into account through the consideration of the contribution from the atomic stress auto-correlation term only. This conclusion, however, does not mean that only the auto-correlation term represents the contribution to viscosity from the structural relaxation. Previously the role of the structural relaxation for viscosity has been addressed through the considerations of the transitions between inherent structures and within the mode-coupling theory by other authors. In the present work, we study the structural relaxation through the considerations of the parent liquid and the atomic level stress correlations in it. The comparison with the results obtained on the inherent structures also is made. Our current results suggest, as our previous observations, that in the supercooled liquid regime, the vibrational contribution to viscosity extends over the times that are much larger than the Einstein's vibrational period and much larger than the times that it takes for the shear waves to propagate over the model systems. Besides addressing the atomic level shear stress correlations, we also studied correlations between the atomic level pressure elements.

Brief Report: Examination of Correlates of Adaptive Behavior in Children with HFASD Using the BASC-2 Parent Rating Scale

ERIC Educational Resources Information Center

McDonald, Christin A.; Donnelly, James P.; Rodgers, Jonathan D.; Thomeer, Marcus L.; Lopata, Christopher; Jordan, Allyson K.

2017-01-01

This study extended the research on correlates of adaptive functioning of high-functioning children with autism spectrum disorder (HFASD) using the Behavior Assessment System for Children-Second Edition (BASC-2). Specifically, this study investigated the relationships between adaptive behavior and age, IQ, and ASD symptomology, in a…

Macroscopic cartilage repair scoring of defect fill, integration and total points correlate with corresponding items in histological scoring systems - a study in adult sheep.

PubMed

Goebel, L; Orth, P; Cucchiarini, M; Pape, D; Madry, H

2017-04-01

To correlate osteochondral repair assessed by validated macroscopic scoring systems with established semiquantitative histological analyses in an ovine model and to test the hypothesis that important macroscopic individual categories correlate with their corresponding histological counterparts. In the weight-bearing portion of medial femoral condyles (n = 38) of 19 female adult Merino sheep (age 2-4 years; weight 70 ± 20 kg) full-thickness chondral defects were created (size 4 × 8 mm; International Cartilage Repair Society (ICRS) grade 3C) and treated with Pridie drilling. After sacrifice, 1520 blinded macroscopic observations from three observers at 2-3 time points including five different macroscopic scoring systems demonstrating all grades of cartilage repair where correlated with corresponding categories from 418 blinded histological sections. Categories "defect fill" and "total points" of different macroscopic scoring systems correlated well with their histological counterparts from the Wakitani and Sellers scores (all P ≤ 0.001). "Integration" was assessed in both histological scoring systems and in the macroscopic ICRS, Oswestry and Jung scores. Here, a significant relationship always existed (0.020 ≤ P ≤ 0.049), except for Wakitani and Oswestry (P = 0.054). No relationship was observed for the "surface" between histology and macroscopy (all P > 0.05). Major individual morphological categories "defect fill" and "integration", and "total points" of macroscopic scoring systems correlate with their corresponding categories in elementary and complex histological scoring systems. Thus, macroscopy allows to precisely predict key histological aspects of articular cartilage repair, underlining the specific value of macroscopic scoring for examining cartilage repair. Copyright © 2016 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Physical activity measured by physical activity monitoring system correlates with glucose trends reconstructed from continuous glucose monitoring.

PubMed

Zecchin, Chiara; Facchinetti, Andrea; Sparacino, Giovanni; Dalla Man, Chiara; Manohar, Chinmay; Levine, James A; Basu, Ananda; Kudva, Yogish C; Cobelli, Claudio

2013-10-01

In type 1 diabetes mellitus (T1DM), physical activity (PA) lowers the risk of cardiovascular complications but hinders the achievement of optimal glycemic control, transiently boosting insulin action and increasing hypoglycemia risk. Quantitative investigation of relationships between PA-related signals and glucose dynamics, tracked using, for example, continuous glucose monitoring (CGM) sensors, have been barely explored. In the clinic, 20 control and 19 T1DM subjects were studied for 4 consecutive days. They underwent low-intensity PA sessions daily. PA was tracked by the PA monitoring system (PAMS), a system comprising accelerometers and inclinometers. Variations on glucose dynamics were tracked estimating first- and second-order time derivatives of glucose concentration from CGM via Bayesian smoothing. Short-time effects of PA on glucose dynamics were quantified through the partial correlation function in the interval (0, 60 min) after starting PA. Correlation of PA with glucose time derivatives is evident. In T1DM, the negative correlation with the first-order glucose time derivative is maximal (absolute value) after 15 min of PA, whereas the positive correlation is maximal after 40-45 min. The negative correlation between the second-order time derivative and PA is maximal after 5 min, whereas the positive correlation is maximal after 35-40 min. Control subjects provided similar results but with positive and negative correlation peaks anticipated of 5 min. Quantitative information on correlation between mild PA and short-term glucose dynamics was obtained. This represents a preliminary important step toward incorporation of PA information in more realistic physiological models of the glucose-insulin system usable in T1DM simulators, in development of closed-loop artificial pancreas control algorithms, and in CGM-based prediction algorithms for generation of hypoglycemic alerts.

Clinical applications of correlational vestibular autorotation test.

PubMed

Hsieh, Li-Chun; Lin, Te-Ming; Chang, Yu-Min; Kuo, Terry B J; Lee, Gho-She

2015-06-01

The correlational vestibular autorotation test (VAT) system has the advantages of good test-retest reliability and calibrations of absolute degrees of eye movement are unnecessary when acquiring a cross correlation coefficient (CCC). The approach is able to efficiently detect peripheral vestibulopathies. A VAT has some drawbacks including poor test-retest reliability and slippage of sensor. This study aimed to develop a correlational VAT system and to evaluate the reliability and applicability of this system. Twenty healthy participants and 10 vertiginous patients were enrolled. Vertical and horizontal autorotations from 0 to 3 Hz with either closed or open eyes were performed. A small sensor and a wireless transmission technique were used to acquire the electro-ocular graph and head velocity signals. The two signals were analyzed using CCCs to assess the functioning of the vestibular ocular reflex (VOR). The results showed a significantly greater CCC for open-eye versus closed-eye of head autorotations. The CCCs also increased significantly with head rotational frequencies. Moreover, the CCCs significantly correlated with the VOR gains at autorotation frequencies ≥1.0 Hz. The test-retest reliability was good (intraclass correlation coefficients ≥0.85). The vertiginous participants had significantly lower individual CCCs and overall average CCC than age- and-gender matched controls.

Similar predictions of etravirine sensitivity regardless of genotypic testing method used: comparison of available scoring systems.

PubMed

Vingerhoets, Johan; Nijs, Steven; Tambuyzer, Lotke; Hoogstoel, Annemie; Anderson, David; Picchio, Gaston

2012-01-01

The aims of this study were to compare various genotypic scoring systems commonly used to predict virological outcome to etravirine, and examine their concordance with etravirine phenotypic susceptibility. Six etravirine genotypic scoring systems were assessed: Tibotec 2010 (based on 20 mutations; TBT 20), Monogram, Stanford HIVdb, ANRS, Rega (based on 37, 30, 27 and 49 mutations, respectively) and virco(®)TYPE HIV-1 (predicted fold change based on genotype). Samples from treatment-experienced patients who participated in the DUET trials and with both genotypic and phenotypic data (n=403) were assessed using each scoring system. Results were retrospectively correlated with virological response in DUET. κ coefficients were calculated to estimate the degree of correlation between the different scoring systems. Correlation between the five scoring systems and the TBT 20 system was approximately 90%. Virological response by etravirine susceptibility was comparable regardless of which scoring system was utilized, with 70-74% of DUET patients determined as susceptible to etravirine by the different scoring systems achieving plasma viral load <50 HIV-1 RNA copies/ml. In samples classed as phenotypically susceptible to etravirine (fold change in 50% effective concentration ≤3), correlations with genotypic score were consistently high across scoring systems (≥70%). In general, the etravirine genotypic scoring systems produced similar results, and genotype-phenotype concordance was high. As such, phenotypic interpretations, and in their absence all genotypic scoring systems investigated, may be used to reliably predict the activity of etravirine.

Network reliability maximization for stochastic-flow network subject to correlated failures using genetic algorithm and tabu\\xA0search

NASA Astrophysics Data System (ADS)

Yeh, Cheng-Ta; Lin, Yi-Kuei; Yang, Jo-Yun

2018-07-01

Network reliability is an important performance index for many real-life systems, such as electric power systems, computer systems and transportation systems. These systems can be modelled as stochastic-flow networks (SFNs) composed of arcs and nodes. Most system supervisors respect the network reliability maximization by finding the optimal multi-state resource assignment, which is one resource to each arc. However, a disaster may cause correlated failures for the assigned resources, affecting the network reliability. This article focuses on determining the optimal resource assignment with maximal network reliability for SFNs. To solve the problem, this study proposes a hybrid algorithm integrating the genetic algorithm and tabu search to determine the optimal assignment, called the hybrid GA-TS algorithm (HGTA), and integrates minimal paths, recursive sum of disjoint products and the correlated binomial distribution to calculate network reliability. Several practical numerical experiments are adopted to demonstrate that HGTA has better computational quality than several popular soft computing algorithms.

Generic dynamical features of quenched interacting quantum systems: Survival probability, density imbalance, and out-of-time-ordered correlator

NASA Astrophysics Data System (ADS)

Torres-Herrera, E. J.; García-García, Antonio M.; Santos, Lea F.

2018-02-01

We study numerically and analytically the quench dynamics of isolated many-body quantum systems. Using full random matrices from the Gaussian orthogonal ensemble, we obtain analytical expressions for the evolution of the survival probability, density imbalance, and out-of-time-ordered correlator. They are compared with numerical results for a one-dimensional-disordered model with two-body interactions and shown to bound the decay rate of this realistic system. Power-law decays are seen at intermediate times, and dips below the infinite time averages (correlation holes) occur at long times for all three quantities when the system exhibits level repulsion. The fact that these features are shared by both the random matrix and the realistic disordered model indicates that they are generic to nonintegrable interacting quantum systems out of equilibrium. Assisted by the random matrix analytical results, we propose expressions that describe extremely well the dynamics of the realistic chaotic system at different time scales.

Assessment of Stone Complexity for PCNL: A Systematic Review of the Literature, How Best Can We Record Stone Complexity in PCNL?

PubMed

Withington, John; Armitage, James; Finch, William; Wiseman, Oliver; Glass, Jonathan; Burgess, Neil

2016-01-01

This study aims to systematically review the literature reporting tools for scoring stone complexity and the stratification of outcomes by stone complexity. In doing so, we aim to determine whether the evidence favors uniform adoption of any one scoring system. PubMed and Embase databases were systematically searched for relevant studies from 2004 to 2014. Reports selected according to predetermined inclusion and exclusion criteria were appraised in terms of methodologic quality and their findings summarized in structured tables. After review, 15 studies were considered suitable for inclusion. Four distinct scoring systems were identified and a further five studies that aimed to validate aspects of those scoring systems. Six studies reported the stratification of outcomes by stone complexity, without specifically defining a scoring system. All studies reported some correlation between stone complexity and stone clearance. Correlation with complications was less clearly established, where investigated. This review does not allow us to firmly recommend one scoring system over the other. However, the quality of evidence supporting validation of the Guy's Stone Score is marginally superior, according to the criteria applied in this study. Further evaluation of the interobserver reliability of this scoring system is required.

Donabedian's structure-process-outcome quality of care model: Validation in an integrated trauma system.

PubMed

Moore, Lynne; Lavoie, André; Bourgeois, Gilles; Lapointe, Jean

2015-06-01

According to Donabedian's health care quality model, improvements in the structure of care should lead to improvements in clinical processes that should in turn improve patient outcome. This model has been widely adopted by the trauma community but has not yet been validated in a trauma system. The objective of this study was to assess the performance of an integrated trauma system in terms of structure, process, and outcome and evaluate the correlation between quality domains. Quality of care was evaluated for patients treated in a Canadian provincial trauma system (2005-2010; 57 centers, n = 63,971) using quality indicators (QIs) developed and validated previously. Structural performance was measured by transposing on-site accreditation visit reports onto an evaluation grid according to American College of Surgeons criteria. The composite process QI was calculated as the average sum of proportions of conformity to 15 process QIs derived from literature review and expert opinion. Outcome performance was measured using risk-adjusted rates of mortality, complications, and readmission as well as hospital length of stay (LOS). Correlation was assessed with Pearson's correlation coefficients. Statistically significant correlations were observed between structure and process QIs (r = 0.33), and process and outcome QIs (r = -0.33 for readmission, r = -0.27 for LOS). Significant positive correlations were also observed between outcome QIs (r = 0.37 for mortality-readmission; r = 0.39 for mortality-LOS and readmission-LOS; r = 0.45 for mortality-complications; r = 0.34 for readmission-complications; 0.63 for complications-LOS). Significant correlations between quality domains observed in this study suggest that Donabedian's structure-process-outcome model is a valid model for evaluating trauma care. Trauma centers that perform well in terms of structure also tend to perform well in terms of clinical processes, which in turn has a favorable influence on patient outcomes. Prognostic study, level III.

Nailfold capillaroscopy in systemic lupus erythematosus: A systematic review and critical appraisal.

PubMed

Cutolo, Maurizio; Melsens, Karin; Wijnant, Sara; Ingegnoli, Francesca; Thevissen, Kristof; De Keyser, Filip; Decuman, Saskia; Müller-Ladner, Ulf; Piette, Yves; Riccieri, Valeria; Ughi, Nicola; Vandecasteele, Els; Vanhaecke, Amber; Smith, Vanessa

2018-04-01

Nailfold capillaroscopy is an easy, non-invasive technique to assess microvascular involvement in rheumatic diseases. Multiple studies describe capillaroscopic changes in systemic lupus erythematosus (SLE), including a wide range of non-specific findings. On behalf of the European League Against Rheumatism (EULAR) study group on microcirculation in rheumatic diseases, a systematic review was done to obtain all original research studies (in English) in which SLE patients had capillaroscopy. Forty such studies are identified. This article firstly provides a résumé of the results of these studies according to capillaroscopic parameters (density, dimensions, morphology, haemorrhages), semi-quantitative assessment and qualitative assessment of capillaroscopy in SLE patients. Secondly, the correlations between capillaroscopic parameters in SLE patients and clinical and laboratory parameters (including auto-immune parameters) are outlined. The following capillaroscopic parameters are found to be significantly more prevalent in SLE patients compared to healthy controls: tortuous capillaries, abnormal morphology and haemorrhages. Hairpin-shaped capillaries are significantly less prevalent than in healthy persons. The semi-quantitatively determined nailfold capillaroscopic score (NFC score) in SLE patients is also higher than in healthy controls. Several correlations between clinical and laboratory parameters and capillaroscopic parameters are identified in the review. Disease activity is correlated with NFC score in seven studies, with abnormal morphology (i.e. "meandering") in one study and with haemorrhages in one study. Frequent attacks of Raynaud's phenomenon (RP) and gangrene are significantly correlated with dilated capillaries. In two studies a possible correlation between anti-SSA antibodies and lower density of capillaries is withheld. About other immune parameters conflicting results are found. In one study a significant negative correlation is found between 24-hour proteinuria and abnormal morphology (i.e. "meandering"). For the first time, an overview of the nailfold capillaroscopic changes that have been described in SLE and their correlations with clinical and laboratory findings is given. Further large-scale research on the identification of capillaroscopic changes in SLE and their correlations with standardised clinical and laboratory parameters, is ongoing at the EULAR study group on microcirculation in rheumatic diseases. Copyright © 2018 Elsevier B.V. All rights reserved.

The Behavior of Matter under Nonequilibrium Conditions: Fundamental Aspects and Applications: Progress Report for Period August 15, 1989 - April 14, 1990

DOE R&D Accomplishments Database

Prigogine, I.

1989-10-01

As in the previous period, our work has been concerned with the study of the properties of nonequilibrium systems and especially with the mechanism of self-organization. As is well-known, the study of self-organization began with the investigation of hydrodynamical or chemical instabilities studied from the point of view of macroscopic physics. The main outcome is that nonequilibrium generates spatial correlations of macroscopic physics. The main outcome is that nonequilibrium generated spatial correlations of macroscopic range whose characteristics length is an intrinsic property and whose amplitude is determined by nonequilibrium constraints. A survey of the macroscopic approach to nonequilibrium states is given in the paper. "Nonequilibrium States and Long Range Correlations in Chemical Dynamics", by G. Nicolis at al. However, over the last few years important progress has been made in the simulation of nonequilibrium situations using mainly molecular dynamics. It appears now that processes corresponding to self-organization as well as the appearance of long-range correlations can be obtained in this way starting from a program involving Newtonian dynamics (generally the laws of interaction correspond to hard spheres or hard disks). Examples of such types of studies leading to Benard instabilities, to chemical clocks, or to spatial structure formation are given in this report. As a result, we may now view self-organization as a direct expression of tan appropriate microscopic dynamics. This is the reason why we have devoted much work to the study of large Poincare systems (LPS) involving continuous sets of resonances. These systems have been shown to lead, according to the constraints, either to equilibrium situations or to nonequilibrium states involving long range correlations. We discuss LPS in the frame of classical mechanics.

SOLAR SYSTEM MOONS AS ANALOGS FOR COMPACT EXOPLANETARY SYSTEMS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kane, Stephen R.; Hinkel, Natalie R.; Raymond, Sean N., E-mail: skane@ipac.caltech.edu

2013-11-01

The field of exoplanetary science has experienced a recent surge of new systems that is largely due to the precision photometry provided by the Kepler mission. The latest discoveries have included compact planetary systems in which the orbits of the planets all lie relatively close to the host star, which presents interesting challenges in terms of formation and dynamical evolution. The compact exoplanetary systems are analogous to the moons orbiting the giant planets in our solar system, in terms of their relative sizes and semimajor axes. We present a study that quantifies the scaled sizes and separations of the solarmore » system moons with respect to their hosts. We perform a similar study for a large sample of confirmed Kepler planets in multi-planet systems. We show that a comparison between the two samples leads to a similar correlation between their scaled sizes and separation distributions. The different gradients of the correlations may be indicative of differences in the formation and/or long-term dynamics of moon and planetary systems.« less

A financial network perspective of financial institutions' systemic risk contributions

NASA Astrophysics Data System (ADS)

Huang, Wei-Qiang; Zhuang, Xin-Tian; Yao, Shuang; Uryasev, Stan

2016-08-01

This study considers the effects of the financial institutions' local topology structure in the financial network on their systemic risk contribution using data from the Chinese stock market. We first measure the systemic risk contribution with the Conditional Value-at-Risk (CoVaR) which is estimated by applying dynamic conditional correlation multivariate GARCH model (DCC-MVGARCH). Financial networks are constructed from dynamic conditional correlations (DCC) with graph filtering method of minimum spanning trees (MSTs). Then we investigate dynamics of systemic risk contributions of financial institution. Also we study dynamics of financial institution's local topology structure in the financial network. Finally, we analyze the quantitative relationships between the local topology structure and systemic risk contribution with panel data regression analysis. We find that financial institutions with greater node strength, larger node betweenness centrality, larger node closeness centrality and larger node clustering coefficient tend to be associated with larger systemic risk contributions.

Changes in Cross-Correlations as an Indicator for Systemic Risk

NASA Astrophysics Data System (ADS)

Zheng, Zeyu; Podobnik, Boris; Feng, Ling; Li, Baowen

2012-11-01

The 2008-2012 global financial crisis began with the global recession in December 2007 and exacerbated in September 2008, during which the U.S. stock markets lost 20% of value from its October 11 2007 peak. Various studies reported that financial crisis are associated with increase in both cross-correlations among stocks and stock indices and the level of systemic risk. In this paper, we study 10 different Dow Jones economic sector indexes, and applying principle component analysis (PCA) we demonstrate that the rate of increase in principle components with short 12-month time windows can be effectively used as an indicator of systemic risk--the larger the change of PC1, the higher the increase of systemic risk. Clearly, the higher the level of systemic risk, the more likely a financial crisis would occur in the near future.

Using temporal detrending to observe the spatial correlation of traffic.

PubMed

Ermagun, Alireza; Chatterjee, Snigdhansu; Levinson, David

2017-01-01

This empirical study sheds light on the spatial correlation of traffic links under different traffic regimes. We mimic the behavior of real traffic by pinpointing the spatial correlation between 140 freeway traffic links in a major sub-network of the Minneapolis-St. Paul freeway system with a grid-like network topology. This topology enables us to juxtapose the positive and negative correlation between links, which has been overlooked in short-term traffic forecasting models. To accurately and reliably measure the correlation between traffic links, we develop an algorithm that eliminates temporal trends in three dimensions: (1) hourly dimension, (2) weekly dimension, and (3) system dimension for each link. The spatial correlation of traffic links exhibits a stronger negative correlation in rush hours, when congestion affects route choice. Although this correlation occurs mostly in parallel links, it is also observed upstream, where travelers receive information and are able to switch to substitute paths. Irrespective of the time-of-day and day-of-week, a strong positive correlation is witnessed between upstream and downstream links. This correlation is stronger in uncongested regimes, as traffic flow passes through consecutive links more quickly and there is no congestion effect to shift or stall traffic. The extracted spatial correlation structure can augment the accuracy of short-term traffic forecasting models.

Using temporal detrending to observe the spatial correlation of traffic

PubMed Central

2017-01-01

This empirical study sheds light on the spatial correlation of traffic links under different traffic regimes. We mimic the behavior of real traffic by pinpointing the spatial correlation between 140 freeway traffic links in a major sub-network of the Minneapolis—St. Paul freeway system with a grid-like network topology. This topology enables us to juxtapose the positive and negative correlation between links, which has been overlooked in short-term traffic forecasting models. To accurately and reliably measure the correlation between traffic links, we develop an algorithm that eliminates temporal trends in three dimensions: (1) hourly dimension, (2) weekly dimension, and (3) system dimension for each link. The spatial correlation of traffic links exhibits a stronger negative correlation in rush hours, when congestion affects route choice. Although this correlation occurs mostly in parallel links, it is also observed upstream, where travelers receive information and are able to switch to substitute paths. Irrespective of the time-of-day and day-of-week, a strong positive correlation is witnessed between upstream and downstream links. This correlation is stronger in uncongested regimes, as traffic flow passes through consecutive links more quickly and there is no congestion effect to shift or stall traffic. The extracted spatial correlation structure can augment the accuracy of short-term traffic forecasting models. PMID:28472093

Does leadership effectiveness correlates with leadership styles in healthcare executives of Iran University of Medical Sciences

PubMed Central

Ebadifard Azar, Farbod; Sarabi Asiabar, Ali

2015-01-01

Background: Effective leadership is essential to passing through obstacles facing the health field.The current health care system in Iran has major problems and gaps in the field of effective leadership. The aim of this study was to evaluate hospital managers’ leadership style through selfassessment and to determine the correlation between leadership styles with healthcare executives’ leadership readiness and leadership effectiveness. Methods: In this cross-sectional study a self-administered questionnaire completed by all internal healthcare executives of all teaching and non-teaching hospitals affiliated to Iran University of Medical Sciences. Questionnaire was composed to determine demographic information, leadership style questions, leadership effectiveness and leadership readiness. Descriptive statistics and Pearson correlation coefficient were used for data analysis. Results: According to the findings, the dominant style of healthcare executives was transformational leadership style (with a score of 4.34). The leadership effectiveness was estimated at about 4.36 that shows the appropriate level of leadership effectiveness. There was a significant correlation (correlation coefficient of 0.244) between leadership readiness and transformational leadership style (p<0.05). Also, there was a significant correlation between leadership effectiveness with transformational (0.051) and transactional (0.216) styles. Conclusion: There was a correlation between leadership readiness and leadership effectiveness with leadership styles. Application of this research will be crucial to universities and healthcare executives. This study suggests that strengthening the scientific basis is essential for leadership readiness and leadership effectiveness in healthcare system. PMID:26000260

Does leadership effectiveness correlates with leadership styles in healthcare executives of Iran University of Medical Sciences.

PubMed

Ebadifard Azar, Farbod; Sarabi Asiabar, Ali

2015-01-01

Effective leadership is essential to passing through obstacles facing the health field.The current health care system in Iran has major problems and gaps in the field of effective leadership. The aim of this study was to evaluate hospital managers' leadership style through selfassessment and to determine the correlation between leadership styles with healthcare executives' leadership readiness and leadership effectiveness. In this cross-sectional study a self-administered questionnaire completed by all internal healthcare executives of all teaching and non-teaching hospitals affiliated to Iran University of Medical Sciences. Questionnaire was composed to determine demographic information, leadership style questions, leadership effectiveness and leadership readiness. Descriptive statistics and Pearson correlation coefficient were used for data analysis. According to the findings, the dominant style of healthcare executives was transformational leadership style (with a score of 4.34). The leadership effectiveness was estimated at about 4.36 that shows the appropriate level of leadership effectiveness. There was a significant correlation (correlation coefficient of 0.244) between leadership readiness and transformational leadership style (p<0.05). Also, there was a significant correlation between leadership effectiveness with transformational (0.051) and transactional (0.216) styles. There was a correlation between leadership readiness and leadership effectiveness with leadership styles. Application of this research will be crucial to universities and healthcare executives. This study suggests that strengthening the scientific basis is essential for leadership readiness and leadership effectiveness in healthcare system.

Autonomic dysfunction and osteoporosis after electrical burn.

PubMed

Roshanzamir, Sharareh; Dabbaghmanesh, Mohammad Hossein; Dabbaghmanesh, Alireza; Nejati, Solmaz

2016-05-01

Several studies have shown the importance of the sympathetic nervous system in bone metabolism. There is an evidence of sympathetic skin response (SSR) impairment in electrical burn patients up to 2 years after their injuries. The acute phase of burn is accompanied by increased bone resorption. Whether the prolonged dysfunction of sympathetic nervous system may result in bone metabolism derangement even after the acute phase of electrical burn is the inspiring question for this study. And we tried to find correlation between SSR abnormality and areal bone mineral density (BMD) in electrical burn patients 6 months or more after the incidents. 42 electrical burn patients (≥6 months prior to study) who did not have a known joint or bone disease, history of neuropathy (central or peripheral), diabetes mellitus or consumption of any drug affecting the autonomic nervous system or evidence of neuropathy in nerve conduction study were recruited. We also gathered a control group of 50 healthy subjects (without electrical burn or the exclusion criteria). They went under dual energy X-ray absorptiometry and SSR study. Data were analyzed statistically with SPSS 16.0 making use of independent t-test and Pearson correlation coefficient. P<0.05 was considered significant statistically. Areal BMD was significantly lower in electrical burn patients than control group (P<0.001). SSR latency was significantly prolonged and its amplitude was significantly reduced in burn patients compared to control group (P<0.001). In burn patients there was an inverse correlation of areal BMD of lumbar vertebrae, left femur neck and total femur with SSR latency and a direct correlation of areal BMD with SSR amplitude. In control group there was just direct correlation of areal BMD of lumbar vertebrae and left femur neck with SSR amplitude. Electrical burn patients are at risk of reduced areal BMD long after their injuries. Sympathetic derangement and impaired SSR are correlated with reduction in areal BMD in these patients. Copyright © 2015 Elsevier Ltd and ISBI. All rights reserved.

Neuroanatomical Correlates of Heterotypic Comorbidity in Externalizing Male Adolescents

ERIC Educational Resources Information Center

Sauder, Colin L.; Beauchaine, Theodore P.; Gatzke-Kopp, Lisa M.; Shannon, Katherine E.; Aylward, Elizabeth

2012-01-01

Children and adolescents with externalizing behavior disorders including attention-deficit/hyperactivity disorder (ADHD) and conduct disorder (CD) often present with symptoms of comorbid internalizing psychopathology. However, few studies have examined central nervous system correlates of such comorbidity. We evaluated interactions between…

Hydrodynamics and long range correlations

NASA Astrophysics Data System (ADS)

Bialas, A.; Zalewski, K.

2011-04-01

It is shown that the recently proposed method of studying the long-range correlations in multiparticle production can be effectively used to verify the hydrodynamic nature of the longitudinal expansion of the partonic system created in the collision. The case of ALICE detector is explicitly considered.

Exact exchange and Wilson-Levy correlation: a pragmatic device for studying complex weakly-bonded systems.

PubMed

Walsh, T R

2005-02-07

The Wilson-Levy (WL) correlation functional is used together with Hartree-Fock (HF) theory to evaluate interaction energies at intermediate separations (i.e. around equilibrium separation) for several weakly-bonded systems. The HF+WL approach reproduces binding trends for all complexes studied: selected rare-gas dimers, isomers of the methane dimer, benzene dimer and naphthalene dimer, and base-pair stacking structures for pyrimidine, cytosine, uracil and guanine dimers. These HF+WL data are contrasted against results obtained from some popular functionals (including B3LYP and PBE), as well as two newly-developed functionals, X3LYP and xPBE. The utility of HF+WL, with reference to exact-exchange (EXX) density-functional theory, is discussed in terms of a suggested EXXWL exchange-correlation functional.

Qubit assisted enhancement of quantum correlations in an optomechanical system

NASA Astrophysics Data System (ADS)

Chakraborty, Subhadeep; Sarma, Amarendra K.

2018-05-01

We perform a theoretical study on quantum correlations in an optomechanical system where the mechanical mirror is perturbatively coupled to an auxiliary qubit. In our study, we consider logarithmic negativity to quantify the degree of stationary entanglement between the cavity field and mechanical mirror, and, Gaussian quantum discord as a witness of the quantumness of the correlation beyond entanglement. Utilizing experimentally feasible parameters, we show that both entanglement and quantum discord enhance significantly with increase in mirror-qubit coupling. Moreover, we find that in presence of the mirror-qubit coupling entanglement could be generated at a considerably lower optomechanical coupling strength, which is also extremely robust against the environmental temperature. Overall, our proposed scheme offers some considerable advantages for realizing the continuous-variable quantum information and communication.

Boosting spin-caloritronic effects by attractive correlations in molecular junctions.

PubMed

Weymann, Ireneusz

2016-01-25

In nanoscopic systems quantum confinement and interference can lead to an enhancement of thermoelectric properties as compared to conventional bulk materials. For nanostructures, such as molecules or quantum dots coupled to external leads, the thermoelectric figure of merit can reach or even exceed unity. Moreover, in the presence of external magnetic field or when the leads are ferromagnetic, an applied temperature gradient can generate a spin voltage and an associated spin current flow in the system, which makes such nanostructures particularly interesting for future thermoelectric applications. In this study, by using the numerical renormalization group method, we examine the spin-dependent thermoelectric transport properties of a molecular junction involving an orbital level with attractive Coulomb correlations coupled to ferromagnetic leads. We analyze how attractive correlations affect the spin-resolved transport properties of the system and find a nontrivial dependence of the conductance and tunnel magnetoresistance on the strength and sign of those correlations. We also demonstrate that attractive correlations can lead to an enhancement of the spin thermopower and the figure of merit, which can be controlled by a gate voltage.

Describing a Strongly Correlated Model System with Density Functional Theory.

PubMed

Kong, Jing; Proynov, Emil; Yu, Jianguo; Pachter, Ruth

2017-07-06

The linear chain of hydrogen atoms, a basic prototype for the transition from a metal to Mott insulator, is studied with a recent density functional theory model functional for nondynamic and strong correlation. The computed cohesive energy curve for the transition agrees well with accurate literature results. The variation of the electronic structure in this transition is characterized with a density functional descriptor that yields the atomic population of effectively localized electrons. These new methods are also applied to the study of the Peierls dimerization of the stretched even-spaced Mott insulator to a chain of H 2 molecules, a different insulator. The transitions among the two insulating states and the metallic state of the hydrogen chain system are depicted in a semiquantitative phase diagram. Overall, we demonstrate the capability of studying strongly correlated materials with a mean-field model at the fundamental level, in contrast to the general pessimistic view on such a feasibility.

Synthesis of the Hydrogeologic Framework of the Floridan Aquifer System and Delineation of a Major Avon Park Permeable Zone in Central and Southern Florida

USGS Publications Warehouse

Reese, Ronald S.; Richardson, Emily

2008-01-01

The carbonate Floridan aquifer system of central and southern Florida (south of a latitude of about 29 degrees north) is an invaluable resource with a complex framework that has previously been mapped and managed primarily in a subregional context according to geopolitical boundaries. As interest and use of the Floridan aquifer system in this area increase, a consistent regional hydrogeologic framework is needed for effective management across these boundaries. This study synthesizes previous studies on the Floridan aquifer system and introduces a new regional hydrogeologic conceptual framework, linking physical relations between central and southern Florida and between the west and east coastal areas. The differences in hydrogeologic nomenclature and interpretation across the study area from previous studies were identified and resolved. The Floridan aquifer system consists of the Upper Floridan aquifer, middle confining unit, and Lower Floridan aquifer. This study introduces and delineates a new major, regional productive zone or subaquifer, referred to as the Avon Park permeable zone. This zone is contained within the middle confining unit and synthesizes an extensive zone that has been referred to differently in different parts of the study area in previous studies. The name of this zone derives from the description of this zone as the ?Avon Park highly permeable zone? in west-central Florida in a previous study. Additionally, this zone has been identified previously in southeastern Florida as the ?middle Floridan aquifer.? An approximately correlative or approximate time-stratigraphic framework was developed and was used to provide guidance in the identification and determination of aquifers, subaquifers, and confining units within the Floridan aquifer system and to determine their structural relations. Two stratigraphic marker horizons within the Floridan aquifer system and a marker unit near the top of the aquifer system were delineated or mapped. The marker horizons are correlative points in the stratigraphic section rather than a unit with upper and lower boundaries. The two marker horizons and the marker unit originated from previous studies, wherein they were based on lithology and correlation of geophysical log signatures observed in boreholes. The depths of these marker horizons and the marker unit were extended throughout the study area by correlation of natural gamma-ray logs between wells. The Floridan aquifer system includes, in ascending order, the upper part of the Cedar Keys Formation, Oldsmar Formation, Avon Park Formation, Ocala Limestone, Suwannee Limestone, and in some areas the lower part of the Hawthorn Group. The first marker horizon is in the lower part of the aquifer system near the top of the Oldsmar Formation and is associated with the top of distinctive glauconitic limestone beds that are present in some regions; the second marker horizon is near the middle of the aquifer system in the middle part of the Avon Park Formation. The marker unit lies at the top of a basal unit in the Hawthorn Group and provides a stratigraphic constraint for the top of the Floridan aquifer system. The marker horizons do not have distinguishing lithologic characteristics or a characteristic gamma-ray log pattern in all areas but are still thought to be valid because of correlation of the entire section and correlation of all sufficiently deep wells with gamma-ray logs. The Avon Park permeable zone is contained entirely within the Avon Park Formation; its position within the section is either near the middle Avon Park marker horizon or within a thick part of the section that extends several hundred feet above the marker horizon. This subaquifer is present over most of the study area and characteristically consists of thick units of dolostone and interbedded limestone, and limestone in its upper part. Permeability is primarily associated with fracturing. This subaquifer is well developed in west-cen

An ultrasonic pseudorandom signal-correlation system

NASA Astrophysics Data System (ADS)

Elias, C. M.

1980-01-01

A working ultrasonic pseudorandom signal-correlation system is described which, unlike ultrasonic random signal-correlation systems, does not require an acoustic delay line. Elimination of the delay line allows faster data acquisition and better range resolution. The system uses two identical shift-register type generators to produce pseudonoise bursts which are subsequences of a 65 535-bit complementary m-sequence. One generator produces the transmitted bursts while the other generates identical reference bursts which start at a variable correlation delay time after the transmitted bursts. The reference bursts are cross-correlated with the received echoes to obtain the approximate impulse response of the transducer/specimen system under test. Range sidelobes are reduced by transmitting and correlating many bursts at a given correlation delay before incrementing the delay. Signal-to-sidelobe ratios of greater than 47 dB have been obtained using this method. Limitations of the system due to sampling constraints and the pseudonoise power spectrum are discussed, and the system design and implementation are outlined. Results of experimental characterization of the system show that the pseudorandom signal-correlation system has approximately the same range resolution as a conventional pulse-echo system but can yield a significant increase in signal-to-noise ratio (SNR).

JOURNAL CLUB: Assessment of Interobserver Variability in the Peer Review Process: Should We Agree to Disagree?

PubMed

Verma, Nupur; Hippe, Daniel S; Robinson, Jeffrey D

2016-12-01

Peer review is an important and necessary part of radiology. There are several options to perform the peer review process. This study examines the reproducibility of peer review by comparing two scoring systems. American Board of Radiology-certified radiologists from various practice environments and subspecialties were recruited to score deidentified examinations on a web-based PACS with two scoring systems, RADPEER and Cleareview. Quantitative analysis of the scores was performed for interrater agreement. Interobserver variability was high for both the RADPEER and Cleareview scoring systems. The interobserver correlations (kappa values) were 0.17-0.23 for RADPEER and 0.10-0.16 for Cleareview. Interrater correlation was not statistically significantly different when comparing the RADPEER and Cleareview systems (p = 0.07-0.27). The kappa values were low for the Cleareview subscores when we evaluated for missed findings (0.26), satisfaction of search (0.17), and inadequate interpretation of findings (0.12). Our study confirms the previous report of low interobserver correlation when using the peer review process. There was low interobserver agreement seen when using both the RADPEER and the Cleareview scoring systems.

Electromagnetic fields in small systems from a multiphase transport model

NASA Astrophysics Data System (ADS)

Zhao, Xin-Li; Ma, Yu-Gang; Ma, Guo-Liang

2018-02-01

We calculate the electromagnetic fields generated in small systems by using a multiphase transport (AMPT) model. Compared to A +A collisions, we find that the absolute electric and magnetic fields are not small in p +Au and d +Au collisions at energies available at the BNL Relativistic Heavy Ion Collider and in p +Pb collisions at energies available at the CERN Large Hadron Collider. We study the centrality dependencies and the spatial distributions of electromagnetic fields. We further investigate the azimuthal fluctuations of the magnetic field and its correlation with the fluctuating geometry using event-by-event simulations. We find that the azimuthal correlation 〈" close="〉cos(ϕα+ϕβ-2 ΨRP)〉">cos2 (ΨB-Ψ2) between the magnetic field direction and the second-harmonic participant plane is almost zero in small systems with high multiplicities, but not in those with low multiplicities. This indicates that the charge azimuthal correlation is not a valid probe to study the chiral magnetic effect (CME) in small systems with high multiplicities. However, we suggest searching for possible CME effects in small systems with low multiplicities.

Predicting Student Success via Online Homework Usage

ERIC Educational Resources Information Center

Bowman, Charles R.; Gulacar, Ozcan; King, Daniel B.

2014-01-01

With the amount of data available through an online homework system about students' study habits, it stands to reason that such systems can be used to identify likely student outcomes. A study was conducted to see how student usage of an online chemistry homework system (OWL) correlated with student success in a general chemistry course. Online…

Validation of the videofluoroscopic dysphagia scale in various etiologies.

PubMed

Kim, Juyong; Oh, Byung-Mo; Kim, Jung Yoon; Lee, Goo Joo; Lee, Seung Ah; Han, Tai Ryoon

2014-08-01

The videofluoroscopic dysphagia scale (VDS) was developed as an objective predictor of the prognosis of dysphagia after stroke. We evaluated the clinical validity of the VDS for various diseases. We reviewed the medical records of 1,995 dysphagic patients (1,222 men and 773 women) who underwent videofluoroscopic studies in Seoul National University Hospital from April 2002 through December 2009. Their American Speech–Language–Hearing Association’s National Outcome Measurement System (ASHA NOMS) swallowing scale, clinical dysphagia scale (CDS), and VDS scores were evaluated on the basis of the clinical and/or videofluoroscopic findings by the consensus of two physiatrists. The correlations between the VDS and the other scales were calculated. The VDS displayed significant correlations with the ASHA NOMS swallowing scale and the CDS in every disease group (p < 0.001 in all groups, including central and peripheral nervous system disorders), and these correlations were more apparent for spinal cord injury, peripheral nerve system disorders, and neurodegenerative diseases (correlation coefficients between the VDS and the ASHA NOMS swallowing scale: −0.603, −0.602, and −0.567, respectively). This study demonstrated that the VDS is applicable to dysphagic patients with numerous etiologies that cause dysphagia

Detection of sub-threshold periodic signal by multiplicative and additive cross-correlated sine-Wiener noises in the FitzHugh-Nagumo neuron

NASA Astrophysics Data System (ADS)

Yao, Yuangen; Ma, Chengzhang; Wang, Canjun; Yi, Ming; Gui, Rong

2018-02-01

We study the effects of multiplicative and additive cross-correlated sine-Wiener (CCSW) noises on the performance of sub-threshold periodic signal detection in the FitzHugh-Nagumo (FHN) neuron by calculating Fourier coefficients Q for measuring synchronization between sub-threshold input signal and the response of system. CCSW noises-induced transitions of electrical activity in the FHN neuron model can be observed. Moreover, the performance of sub-threshold periodic signal detection is achieved at moderate noise strength, cross-correlation time and cross-correlation strength of CCSW noises, which indicate the occurrence of CCSW noises-induced stochastic resonance. Furthermore, the performance of sub-threshold signal detection is strongly sensitive to cross-correlation time of CCSW noises. Therefore, the performance can be effectively controlled by regulating cross-correlation time of CCSW noises. These results provide a possible mechanism for amplifying or detecting the sub-threshold signal in the nervous system.

Correlation between sonography and antibody activity in patients with Hashimoto thyroiditis.

PubMed

Willms, Arnulf; Bieler, Dan; Wieler, Helmut; Willms, Diana; Kaiser, Klaus P; Schwab, Robert

2013-11-01

Patients with Hashimoto thyroiditis show structural changes of the thyroid that can be identified by a variety of sonographic criteria. We conducted this study to investigate whether there is a correlation between sonography and antibody activity and to assess the role of sonography in the diagnosis and follow-up of Hashimoto thyroiditis. In addition, we present a new classification system (termed the VESINC system [volume, echogenicity, sonographic texture, pseudonodular hypoechoic infiltration, nodules, and cysts]), which helps improve the clarity of sonographic findings. The study included 223 consecutive patients with previously diagnosed Hashimoto autoimmune thyroiditis who attended the thyroid clinic of the German Armed Forces Central Hospital in Koblenz for follow-up examinations between 2006 and 2008. Laboratory tests were performed to measure the levels of free triiodothyronine, free thyroxine, thyrotropin, anti-thyroglobulin antibodies (TgAbs), and antithyroid peroxidase antibodies (TPOAbs). Sonography was performed according to a strict protocol. We then assessed whether a correlation existed between antibody activity and the 6 sonographic variables of the VESINC system. Hypoechogenicity, heterogeneity, and pseudonodular hypoechoic infiltration were associated with significantly higher TPOAb activity (P < .001). There were no significant correlations between the other sonographic variables examined (cysts, nodules, and volume) or the biometric data with the TPOAb and TgAb levels. In addition, an assessment of TgAb levels did not show significant differences in correlations with any of the sonographic variables. Sonography is a noninvasive diagnostic imaging modality that provides information about the level of inflammatory activity. Markedly decreased echogenicity, heterogeneity, and multifocal pseudoinodular hypoechoic infiltration are indicative of a high level of inflammatory activity. The sonographic classification system presented here (VESINC system) can be a useful tool for comparing sonographic findings in a rapid and objective manner during follow-up of Hashimoto thyroiditis.

Bounds on the cross-correlation functions of state m-sequences

NASA Astrophysics Data System (ADS)

Woodcock, C. F.; Davies, Phillip A.; Shaar, Ahmed A.

1987-03-01

Lower and upper bounds on the peaks of the periodic Hamming cross-correlation function for state m-sequences, which are often used in frequency-hopped spread-spectrum systems, are derived. The state position mapped (SPM) sequences of the state m-sequences are described. The use of SPM sequences for OR-channel code division multiplexing is studied. The relation between the Hamming cross-correlation function and the correlation function of SPM sequence is examined. Numerical results which support the theoretical data are presented.

Revealing a universal planet-metallicity correlation for planets of different solar-type stars

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Ji; Fischer, Debra A., E-mail: ji.wang@yale.edu

2015-01-01

The metallicity of exoplanet systems serves as a critical diagnostic of planet formation mechanisms. Previous studies have demonstrated the planet–metallicity correlation for large planets (R{sub P} ⩾ 4 R{sub E}); however, a correlation has not been found for smaller planets. With a sample of 406 Kepler objects of interest whose stellar properties are determined spectroscopically, we reveal a universal planet–metallicity correlation: not only gas-giant planets (3.9 R{sub E}

Fuel system technology overview

NASA Technical Reports Server (NTRS)

Friedman, R.

1980-01-01

Fuel system research and technology studies are being conducted to investigate the correlations and interactions of aircraft fuel system design and environment with applicable characteristics of the fuel. Topics include: (1) analysis of in-flight fuel temperatures; (2) fuel systems for high freezing point fuels; (3) experimental study of low temperature pumpability; (4) full scale fuel tank simulation; and (5) rapid freezing point measurement.

Randic and Schultz molecular topological indices and their correlation with some X-ray absorption parameters

NASA Astrophysics Data System (ADS)

Khatri, Sunil; Kekre, Pravin A.; Mishra, Ashutosh

2016-10-01

The properties of a molecular system are affected by the topology of molecule. Therefore many studies have been made where the various physic-chemical properties are correlated with the topological indices. These studies have shown a very good correlation demonstrating the utility of the graph theoretical approach. It is, therefore, very natural to expect that the various physical properties obtained by the X-ray absorption spectra may also show correlation with the topological indices. Some complexes were used to establish correlation between topological indices and some X-ray absorption parameters like chemical shift. The chemical shift is on the higher energy side of the metal edge in these complexes. The result obtained in these studies shows that the topological indices of organic molecule acting as a legands can be used for estimating edge shift theoretically.

A novel method for repeatedly generating speckle patterns used in digital image correlation

NASA Astrophysics Data System (ADS)

Zhang, Juan; Sweedy, Ahmed; Gitzhofer, François; Baroud, Gamal

2018-01-01

Speckle patterns play a key role in Digital Image Correlation (DIC) measurement, and generating an optimal speckle pattern has been the goal for decades now. The usual method of generating a speckle pattern is by manually spraying the paint on the specimen. However, this makes it difficult to reproduce the optimal pattern for maintaining identical testing conditions and achieving consistent DIC results. This study proposed and evaluated a novel method using an atomization system to repeatedly generate speckle patterns. To verify the repeatability of the speckle patterns generated by this system, simulation and experimental studies were systematically performed. The results from both studies showed that the speckle patterns and, accordingly, the DIC measurements become highly accurate and repeatable using the proposed atomization system.

Estimation of positive semidefinite correlation matrices by using convex quadratic semidefinite programming.

PubMed

Fushiki, Tadayoshi

2009-07-01

The correlation matrix is a fundamental statistic that is used in many fields. For example, GroupLens, a collaborative filtering system, uses the correlation between users for predictive purposes. Since the correlation is a natural similarity measure between users, the correlation matrix may be used in the Gram matrix in kernel methods. However, the estimated correlation matrix sometimes has a serious defect: although the correlation matrix is originally positive semidefinite, the estimated one may not be positive semidefinite when not all ratings are observed. To obtain a positive semidefinite correlation matrix, the nearest correlation matrix problem has recently been studied in the fields of numerical analysis and optimization. However, statistical properties are not explicitly used in such studies. To obtain a positive semidefinite correlation matrix, we assume the approximate model. By using the model, an estimate is obtained as the optimal point of an optimization problem formulated with information on the variances of the estimated correlation coefficients. The problem is solved by a convex quadratic semidefinite program. A penalized likelihood approach is also examined. The MovieLens data set is used to test our approach.

40 CFR Appendix IV to Part 92 - Guidelines for Determining Equivalency Between Emission Measurement Systems

Code of Federal Regulations, 2010 CFR

2010-07-01

... Emission Measurement Systems This appendix describes a series of correlation criteria that EPA considers to... results from each system. (b) Correlation criteria for particulate measurements. (1) The correlation... system (i.e., avgalt/avgspc) should be between 0.97 and 1.05. (c) Correlation criteria for other...

40 CFR Appendix IV to Part 92 - Guidelines for Determining Equivalency Between Emission Measurement Systems

Code of Federal Regulations, 2011 CFR

2011-07-01

... Emission Measurement Systems This appendix describes a series of correlation criteria that EPA considers to... results from each system. (b) Correlation criteria for particulate measurements. (1) The correlation... system (i.e., avgalt/avgspc) should be between 0.97 and 1.05. (c) Correlation criteria for other...

Development and Validation of a Pressurization System Model for a Crossfeed Subscale Water Test Article

NASA Technical Reports Server (NTRS)

Nguyen, Han; Mazurkivich, Pete

2006-01-01

A pressurization system model was developed for a crossfeed subscale water test article using the EASY5 modeling software. The model consisted of an integrated tank pressurization and pressurization line model. The tank model was developed using the general purpose library, while the line model was assembled from the gas dynamic library. The pressurization system model was correlated to water test data obtained from nine test runs conducted on the crossfeed subscale test article. The model was first correlated to a representative test run and frozen. The correlated model was then used to predict the tank pressures and compared with the test data for eight other runs. The model prediction showed excellent agreement with the test data, allowing it to be used in a later study to analyze the pressurization system performance of a full-scale bimese vehicle with cryogenic propellants.

The influence of systemic hemodynamics and oxygen transport on cerebral oxygen saturation in neonates after the Norwood procedure.

PubMed

Li, Jia; Zhang, Gencheng; Holtby, Helen; Guerguerian, Anne-Marie; Cai, Sally; Humpl, Tilman; Caldarone, Christopher A; Redington, Andrew N; Van Arsdell, Glen S

2008-01-01

Ischemic brain injury is an important morbidity in neonates after the Norwood procedure. Its relationship to systemic hemodynamic oxygen transport is poorly understood. Sixteen neonates undergoing the Norwood procedure were studied. Continuous cerebral oxygen saturation was measured by near-infrared spectroscopy. Continuous oxygen consumption was measured by respiratory mass spectrometry. Pulmonary and systemic blood flow, systemic vascular resistance, oxygen delivery, and oxygen extraction ratio were derived with measurements of arterial, and superior vena cava and pulmonary venous gases and pressures at 2- to 4-hour intervals during the first 72 hours in the intensive care unit. Mean cerebral oxygen saturation was 66% +/- 12% before the operation, reduced to 51% +/- 13% on arrival in the intensive care unit, and remained low during the first 8 hours; it increased to 56% +/- 9% at 72 hours, still significantly lower than the preoperative level (P < .05). Postoperatively, cerebral oxygen saturation was closely and positively correlated with systemic arterial pressure, arterial oxygen saturation, and arterial oxygen tension and negatively with oxygen extraction ratio (P < .0001 for all). Cerebral oxygen saturation was moderately and positively correlated with systemic blood flow and oxygen delivery (P < .0001 for both). It was weakly and positively correlated with pulmonary blood flow (P = .001) and hemoglobin (P = .02) and negatively correlated with systemic vascular resistance (P = .003). It was not correlated with oxygen consumption (P > .05). Cerebral oxygen saturation decreased significantly in neonates during the early postoperative period after the Norwood procedure and was significantly influenced by systemic hemodynamic and metabolic events. As such, hemodynamic interventions to modify systemic oxygen transport may provide further opportunities to reduce the risk of cerebral ischemia and improve neurodevelopmental outcomes.

Hybrid Correlation Energy (HyCE): An Approach Based on Separate Evaluations of Internal and External Components.

PubMed

Ivanic, Joseph; Schmidt, Michael W

2018-06-04

A novel hybrid correlation energy (HyCE) approach is proposed that determines the total correlation energy via distinct computation of its internal and external components. This approach evolved from two related studies. First, rigorous assessment of the accuracies and size extensivities of a number of electron correlation methods, that include perturbation theory (PT2), coupled-cluster (CC), configuration interaction (CI), and coupled electron pair approximation (CEPA), shows that the CEPA(0) variant of the latter and triples-corrected CC methods consistently perform very similarly. These findings were obtained by comparison to near full CI results for four small molecules and by charting recovered correlation energies for six steadily growing chain systems. Second, by generating valence virtual orbitals (VVOs) and utilizing the CEPA(0) method, we were able to partition total correlation energies into internal (or nondynamic) and external (or dynamic) parts for the aforementioned six chain systems and a benchmark test bed of 36 molecules. When using triple-ζ basis sets it was found that per orbital internal correlation energies were appreciably larger than per orbital external energies and that the former showed far more chemical variation than the latter. Additionally, accumulations of external correlation energies were seen to proceed smoothly, and somewhat linearly, as the virtual space is gradually increased. Combination of these two studies led to development of the HyCE approach, whereby the internal and external correlation energies are determined separately by CEPA(0)/VVO and PT2/external calculations, respectively. When applied to the six chain systems and the 36-molecule benchmark test set it was found that HyCE energies followed closely those of triples-corrected CC and CEPA(0) while easily outperforming MP2 and CCSD. The success of the HyCE approach is more notable when considering that its cost is only slightly more than MP2 and significantly cheaper than the CC approaches.

Theoretical Study of Wave Particle Correlation Measurement via 1-D Electromagnetic Particle Simulation

NASA Astrophysics Data System (ADS)

Ueda, Yoshikatsu; Omura, Yoshiharu; Kojima, Hiro

Spacecraft observation is essentially "one-point measurement", while numerical simulation can reproduce a whole system of physical processes on a computer. By performing particle simulations of plasma wave instabilities and calculating correlation of waves and particles observed at a single point, we examine how well we can infer the characteristics of the whole system by a one-point measurement. We perform various simulation runs with different plasma parameters using one-dimensional electromagnetic particle code (KEMPO1) and calculate 'E dot v' or other moments at a single point. We find good correlation between the measurement and the macroscopic fluctuations of the total simulation region. We make use of the results of the computer experiments in our system design of new instruments 'One-chip Wave Particle Interaction Analyzer (OWPIA)'.

A Study to Determine the Optimal Frequency for Conducting Periodic Dental Examinations (OFDEX)

DTIC Science & Technology

1980-06-01

as the major vehicle by which patients enter into the incremental care system . Unpublished data from studies performed by the Health Care Studies...product-moment correlation was used to measure the strength of the relationship between two variables. Significance tests for correlation coefficients...expected if no relationship existed between variables at given row and column totals. These expected frequencies are then compared to the actual values

Biophysical analysis of bacterial and viral systems. A shock tube study of bio-aerosols and a correlated AFM/nanosims investigation of vaccinia virus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gates, Sean Damien

2013-05-01

The work presented herein is concerned with the development of biophysical methodology designed to address pertinent questions regarding the behavior and structure of select pathogenic agents. Two distinct studies are documented: a shock tube analysis of endospore-laden bio-aerosols and a correlated AFM/NanoSIMS study of the structure of vaccinia virus.

Characterization Of Improved Binary Phase-Only Filters In A Real-Time Coherent Optical Correlation System

NASA Astrophysics Data System (ADS)

Flannery, D.; Keller, P.; Cartwright, S.; Loomis, J.

1987-06-01

Attractive correlation system performance potential is possible using magneto-optic spatial light modulators (SLM) to implement binary phase-only reference filters at high rates, provided the correlation performance of such reduced-information-content filters is adequate for the application. In the case studied here, the desired filter impulse response is a rectangular shape, which cannot be achieved with the usual binary phase-only filter formulation. The correlation application problem is described and techniques for synthesizing improved filter impulse response are considered. A compromise solution involves the cascading of a fixed amplitude-only weighting mask with the binary phase-only SLM. Based on simulations presented, this approach provides improved impulse responses and good correlation performance, while retaining the critical feature of real-time variations of the size, shape, and orientation of the rectangle by electronic programming of the phase pattern in the SLM. Simulations indicate that, for at least one very challenging input scene clutter situation, these filters provide higher correlation signal-to-noise than does "ideal" correlation, i.e. using a perfect rectangle filter response.

The correcting method for the estimation of correlation energies of MF2 (M = Be, Mg, Ca) set molecules

NASA Astrophysics Data System (ADS)

Zhuo, Shuping; Wei, Jichong; Ju, Guanzhi

The intrapair and interpair correlation energies of MF2 (M = Be, Mg, Ca) set molecules are calculated and analysed, and the transferability of inner core correlation effects of Mδ+ are investigated. A detailed analysis of the comparison of correlation energies of neutral atoms with their corresponding ions of Mδ+ and Fδ-/2 is given in terms of the correlation contribution of this component. The study reveals that the total correlation energy of MF2 molecules can be obtained by summing the correlation contributions of Mδ+ and two Fδ-/2 components. This simple estimation method does shed light on the importance of searching useful means for the calculation of electron correlation energy for large biological systems.

Effective Sensor Selection and Data Anomaly Detection for Condition Monitoring of Aircraft Engines

PubMed Central

Liu, Liansheng; Liu, Datong; Zhang, Yujie; Peng, Yu

2016-01-01

In a complex system, condition monitoring (CM) can collect the system working status. The condition is mainly sensed by the pre-deployed sensors in/on the system. Most existing works study how to utilize the condition information to predict the upcoming anomalies, faults, or failures. There is also some research which focuses on the faults or anomalies of the sensing element (i.e., sensor) to enhance the system reliability. However, existing approaches ignore the correlation between sensor selecting strategy and data anomaly detection, which can also improve the system reliability. To address this issue, we study a new scheme which includes sensor selection strategy and data anomaly detection by utilizing information theory and Gaussian Process Regression (GPR). The sensors that are more appropriate for the system CM are first selected. Then, mutual information is utilized to weight the correlation among different sensors. The anomaly detection is carried out by using the correlation of sensor data. The sensor data sets that are utilized to carry out the evaluation are provided by National Aeronautics and Space Administration (NASA) Ames Research Center and have been used as Prognostics and Health Management (PHM) challenge data in 2008. By comparing the two different sensor selection strategies, the effectiveness of selection method on data anomaly detection is proved. PMID:27136561

Effective Sensor Selection and Data Anomaly Detection for Condition Monitoring of Aircraft Engines.

PubMed

Liu, Liansheng; Liu, Datong; Zhang, Yujie; Peng, Yu

2016-04-29

In a complex system, condition monitoring (CM) can collect the system working status. The condition is mainly sensed by the pre-deployed sensors in/on the system. Most existing works study how to utilize the condition information to predict the upcoming anomalies, faults, or failures. There is also some research which focuses on the faults or anomalies of the sensing element (i.e., sensor) to enhance the system reliability. However, existing approaches ignore the correlation between sensor selecting strategy and data anomaly detection, which can also improve the system reliability. To address this issue, we study a new scheme which includes sensor selection strategy and data anomaly detection by utilizing information theory and Gaussian Process Regression (GPR). The sensors that are more appropriate for the system CM are first selected. Then, mutual information is utilized to weight the correlation among different sensors. The anomaly detection is carried out by using the correlation of sensor data. The sensor data sets that are utilized to carry out the evaluation are provided by National Aeronautics and Space Administration (NASA) Ames Research Center and have been used as Prognostics and Health Management (PHM) challenge data in 2008. By comparing the two different sensor selection strategies, the effectiveness of selection method on data anomaly detection is proved.

Nonequilibrium magnetic properties in a two-dimensional kinetic mixed Ising system within the effective-field theory and Glauber-type stochastic dynamics approach.

PubMed

Ertaş, Mehmet; Deviren, Bayram; Keskin, Mustafa

2012-11-01

Nonequilibrium magnetic properties in a two-dimensional kinetic mixed spin-2 and spin-5/2 Ising system in the presence of a time-varying (sinusoidal) magnetic field are studied within the effective-field theory (EFT) with correlations. The time evolution of the system is described by using Glauber-type stochastic dynamics. The dynamic EFT equations are derived by employing the Glauber transition rates for two interpenetrating square lattices. We investigate the time dependence of the magnetizations for different interaction parameter values in order to find the phases in the system. We also study the thermal behavior of the dynamic magnetizations, the hysteresis loop area, and dynamic correlation. The dynamic phase diagrams are presented in the reduced magnetic field amplitude and reduced temperature plane and we observe that the system exhibits dynamic tricritical and reentrant behaviors. Moreover, the system also displays a double critical end point (B), a zero-temperature critical point (Z), a critical end point (E), and a triple point (TP). We also performed a comparison with the mean-field prediction in order to point out the effects of correlations and found that some of the dynamic first-order phase lines, which are artifacts of the mean-field approach, disappeared.

Candidate-penetrative-fracture mapping of the Grand Canyon area, Arizona, from spatial correlation of deep geophysical features and surficial lineaments

USGS Publications Warehouse

Gettings, Mark E.; Bultman, Mark W.

2005-01-01

Some aquifers of the southwestern Colorado Plateaus Province are deeply buried and overlain by several impermeable shale layers, and so recharge to the aquifer probably is mainly by seepage down penetrative-fracture systems. The purpose of this 2-year study, sponsored by the U.S. National Park Service, was to map candidate deep penetrative fractures over a 120,000-km2 area, using gravity and aeromagnetic-anomaly data together with surficial-fracture data. The study area was on the Colorado Plateau south of the Grand Canyon and west of Black Mesa; mapping was carried out at a scale of 1:250,000. The resulting database constitutes a spatially registered estimate of deep-fracture locations. Candidate penetrative fractures were located by spatial correlation of horizontal- gradient and analytic-signal maximums of gravity and magnetic anomalies with major surficial lineaments obtained from geologic, topographic, side-looking-airborne-radar, and satellite imagery. The maps define a subset of candidate penetrative fractures because of limitations in the data coverage and the analytical technique. In particular, the data and analytical technique used cannot predict whether the fractures are open or closed. Correlations were carried out by using image-processing software, such that every pixel on the resulting images was coded to uniquely identify which datasets are correlated. The technique correctly identified known and many new deep fracture systems. The resulting penetrative-fracture-distribution maps constitute an objectively obtained, repeatable dataset and a benchmark from which additional studies can begin. The maps also define in detail the tectonic fabrics of the southwestern Colorado Plateaus Province. Overlaying the correlated lineaments on the normalized-density-of-vegetation-index image reveals that many of these lineaments correlate with the boundaries of vegetation zones in drainages and canyons and so may be controlling near-surface water availability in some places. Many derivative products can be produced from the database, such as fracture-density-estimate maps, and maps with the number of correlations color-coded to estimate the possible quality of correlation. The database contained in this report is designed to be used in a geographic information system and image-processing systems, and most data layers are in georeferenced tagged image format (Geotiff) or ARC grids. The report includes 163 map plates and various metadata, supporting, and statistical diagram files.

Non-local propagation of correlations in long-range interacting quantum systems

NASA Astrophysics Data System (ADS)

Lee, A. C.; Richerme, P.; Gong, Z.-X.; Senko, C.; Smith, J.; Foss-Feig, M.; Michalakis, S.; Gorshkov, A. V.; Monroe, C.

2014-05-01

The maximum speed with which information can propagate in a many body quantum system can dictate how demanding the system is to describe numerically and also how quickly disparate sites can become correlated. While these kinds of phenomena may be difficult or even impossible for classical computers to describe, trapped ions provide an excellent platform for investigating this rich quantum many-body physics. Using single-site resolved state-dependent imaging, we experimentally determine the spatial and time-dependent correlations of a far-from-equilibrium quantum many-body system evolving under a long-range Ising- or XY-model Hamiltonian. For varying interaction ranges, we extract the shape of the ``light'' cone and measure the velocity with which correlations propagate through the system. In many cases, we find increasing propagation velocities, which violate the prediction for short-range interactions and, in one instance, cannot be explained by any existing theory. Our results show that even for modest system sizes, trapped ion quantum simulators are well poised to study complex many-body physics which are intractable to classical methods. This work is supported by grants from the U.S. Army Research Office with funding from the DARPA OLE program, IARPA, and the MURI program; and the NSF Physics Frontier Center at JQI.

Development of a web-based and mobile app to support physical activity in individuals with rheumatoid arthritis: results from the second step of a co-design process.

PubMed

Revenäs, Åsa; Opava, Christina H; Martin, Cathrin; Demmelmaier, Ingrid; Keller, Christina; Åsenlöf, Pernilla

2015-02-09

Long-term adherence to physical activity recommendations remains challenging for most individuals with rheumatoid arthritis (RA) despite evidence for its health benefits. The aim of this study was to provide basic data on system requirement specifications for a Web-based and mobile app to self-manage physical activity. More specifically, we explored the target user group, features of the future app, and correlations between the system requirements and the established behavior change techniques (BCTs). We used a participatory action research design. Qualitative data were collected using multiple methods in four workshops. Participants were 5 individuals with RA, a clinical physiotherapist, an officer from the Swedish Rheumatism Association, a Web designer, and 2 physiotherapy researchers. A taxonomy was used to determine the degree of correlation between the system requirements and established BCTs. Participants agreed that the future Web-based and mobile app should be based on two major components important for maintaining physical activity: (1) a calendar feature for goal setting, planning, and recording of physical activity performance and progress, and (2) a small community feature for positive feedback and support from peers. All system requirements correlated with established BCTs, which were coded as 24 different BCTs. To our knowledge, this study is the first to involve individuals with RA as co-designers, in collaboration with clinicians, researchers, and Web designers, to produce basic data to generate system requirement specifications for an eHealth service. The system requirements correlated to the BCTs, making specifications of content and future evaluation of effectiveness possible.

Reliability of the social skills rating system in a group of Iranian children.

PubMed

Shahim, S

2001-12-01

The purpose of this study was to investigate reliability of the Social Skills Rating Systems of Gresham and Elliott for use in Iran. The sample consisted of 304 students aged 6 to 12 years, selected from the elementary schools in Shiraz, Iran. Parents' and teachers' ratings of social skills and behavioural problems and self-rating of social skills were applied in this study. Pearson correlations between parents' and teachers' ratings were low to moderate. Correlations between social skills subdomains and behavioural problems subdomains were low to high. Cronbach coefficients alpha were satisfactory for the two subdomains.

Motion Tracker: Camera-Based Monitoring of Bodily Movements Using Motion Silhouettes

PubMed Central

Westlund, Jacqueline Kory; D’Mello, Sidney K.; Olney, Andrew M.

2015-01-01

Researchers in the cognitive and affective sciences investigate how thoughts and feelings are reflected in the bodily response systems including peripheral physiology, facial features, and body movements. One specific question along this line of research is how cognition and affect are manifested in the dynamics of general body movements. Progress in this area can be accelerated by inexpensive, non-intrusive, portable, scalable, and easy to calibrate movement tracking systems. Towards this end, this paper presents and validates Motion Tracker, a simple yet effective software program that uses established computer vision techniques to estimate the amount a person moves from a video of the person engaged in a task (available for download from http://jakory.com/motion-tracker/). The system works with any commercially available camera and with existing videos, thereby affording inexpensive, non-intrusive, and potentially portable and scalable estimation of body movement. Strong between-subject correlations were obtained between Motion Tracker’s estimates of movement and body movements recorded from the seat (r =.720) and back (r = .695 for participants with higher back movement) of a chair affixed with pressure-sensors while completing a 32-minute computerized task (Study 1). Within-subject cross-correlations were also strong for both the seat (r =.606) and back (r = .507). In Study 2, between-subject correlations between Motion Tracker’s movement estimates and movements recorded from an accelerometer worn on the wrist were also strong (rs = .801, .679, and .681) while people performed three brief actions (e.g., waving). Finally, in Study 3 the within-subject cross-correlation was high (r = .855) when Motion Tracker’s estimates were correlated with the movement of a person’s head as tracked with a Kinect while the person was seated at a desk (Study 3). Best-practice recommendations, limitations, and planned extensions of the system are discussed. PMID:26086771

The oral-systemic disease connection: a retrospective study.

PubMed

Joseph, Bobby K; Kullman, Leif; Sharma, Prem N

2016-11-01

The study aimed at determining the association between oral disease and systemic health based on panoramic radiographs and general health of patients treated at Kuwait University Dental Center. The objective was to determine whether individuals exhibiting good oral health have lower propensity to systemic diseases. A total of 1000 adult patients treated at Kuwait University Dental Center were randomly selected from the patient's records. The general health of patients was assessed from the medical history of each patient recorded during their visit to the clinic. The number of reported diseases and serious symptoms were used to develop a medical index. The oral health of these patients was assessed from panoramic radiographs to create an oral index by evaluating such parameters as caries, periodontitis, periapical lesions, pericoronitis, and tooth loss. In a total of 887 patients, 43.8 % had an oral index between 3 and 8, of which significantly higher (62.1 %) patients were with medical conditions compared to those without (33.2 %; p < 0.001). The Spearmans's correlation (rho') revealed a positive correlation (rho' = 0.360, p 0.001) between oral and medical index. Partial correlation, while controlling demographics, gender, nationality, and age, also showed a significant positive correlation (p < 0.001) between medical and oral index. The findings of this study showed a significant association between oral health and general health and confirmed the findings of previous reports as regards the existing correlation between dental infections and medical disorders. These results are not indicative of a causal relationship when the diagnosis of oral disease was based primarily on radiographic findings. Future research needs to include prospective clinical and interventional studies. The significance of the oral-systemic disease connection highlights the importance of preventing and treating oral disease which have profound medical implications on general health.

Time Correlations in Mode Hopping of Coupled Oscillators

NASA Astrophysics Data System (ADS)

Heltberg, Mathias L.; Krishna, Sandeep; Jensen, Mogens H.

2017-05-01

We study the dynamics in a system of coupled oscillators when Arnold Tongues overlap. By varying the initial conditions, the deterministic system can be attracted to different limit cycles. Adding noise, the mode hopping between different states become a dominating part of the dynamics. We simplify the system through a Poincare section, and derive a 1D model to describe the dynamics. We explain that for some parameter values of the external oscillator, the time distribution of occupancy in a state is exponential and thus memoryless. In the general case, on the other hand, it is a sum of exponential distributions characteristic of a system with time correlations.

Pathways for diffusion in the potential energy landscape of the network glass former SiO2

NASA Astrophysics Data System (ADS)

Niblett, S. P.; Biedermann, M.; Wales, D. J.; de Souza, V. K.

2017-10-01

We study the dynamical behaviour of a computer model for viscous silica, the archetypal strong glass former, and compare its diffusion mechanism with earlier studies of a fragile binary Lennard-Jones liquid. Three different methods of analysis are employed. First, the temperature and time scale dependence of the diffusion constant is analysed. Negative correlation of particle displacements influences transport properties in silica as well as in fragile liquids. We suggest that the difference between Arrhenius and super-Arrhenius diffusive behaviour results from competition between the correlation time scale and the caging time scale. Second, we analyse the dynamics using a geometrical definition of cage-breaking transitions that was proposed previously for fragile glass formers. We find that this definition accurately captures the bond rearrangement mechanisms that control transport in open network liquids, and reproduces the diffusion constants accurately at low temperatures. As the same method is applicable to both strong and fragile glass formers, we can compare correlation time scales in these two types of systems. We compare the time spent in chains of correlated cage breaks with the characteristic caging time and find that correlations in the fragile binary Lennard-Jones system persist for an order of magnitude longer than those in the strong silica system. We investigate the origin of the correlation behaviour by sampling the potential energy landscape for silica and comparing it with the binary Lennard-Jones model. We find no qualitative difference between the landscapes, but several metrics suggest that the landscape of the fragile liquid is rougher and more frustrated. Metabasins in silica are smaller than those in binary Lennard-Jones and contain fewer high-barrier processes. This difference probably leads to the observed separation of correlation and caging time scales.

Nonlocality in many-body quantum systems detected with two-body correlators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tura, J., E-mail: jordi.tura@icfo.es; Augusiak, R.; Sainz, A.B.

Contemporary understanding of correlations in quantum many-body systems and in quantum phase transitions is based to a large extent on the recent intensive studies of entanglement in many-body systems. In contrast, much less is known about the role of quantum nonlocality in these systems, mostly because the available multipartite Bell inequalities involve high-order correlations among many particles, which are hard to access theoretically, and even harder experimentally. Standard, “theorist- and experimentalist-friendly” many-body observables involve correlations among only few (one, two, rarely three...) particles. Typically, there is no multipartite Bell inequality for this scenario based on such low-order correlations. Recently, however,more » we have succeeded in constructing multipartite Bell inequalities that involve two- and one-body correlations only, and showed how they revealed the nonlocality in many-body systems relevant for nuclear and atomic physics [Tura et al., Science 344 (2014) 1256]. With the present contribution we continue our work on this problem. On the one hand, we present a detailed derivation of the above Bell inequalities, pertaining to permutation symmetry among the involved parties. On the other hand, we present a couple of new results concerning such Bell inequalities. First, we characterize their tightness. We then discuss maximal quantum violations of these inequalities in the general case, and their scaling with the number of parties. Moreover, we provide new classes of two-body Bell inequalities which reveal nonlocality of the Dicke states—ground states of physically relevant and experimentally realizable Hamiltonians. Finally, we shortly discuss various scenarios for nonlocality detection in mesoscopic systems of trapped ions or atoms, and by atoms trapped in the vicinity of designed nanostructures.« less

Towards a formal definition of static and dynamic electronic correlations.

PubMed

Benavides-Riveros, Carlos L; Lathiotakis, Nektarios N; Marques, Miguel A L

2017-05-24

Some of the most spectacular failures of density-functional and Hartree-Fock theories are related to an incorrect description of the so-called static electron correlation. Motivated by recent progress in the N-representability problem of the one-body density matrix for pure states, we propose a method to quantify the static contribution to the electronic correlation. By studying several molecular systems we show that our proposal correlates well with our intuition of static and dynamic electron correlation. Our results bring out the paramount importance of the occupancy of the highest occupied natural spin-orbital in such quantification.

Repetition priming influences distinct brain systems: evidence from task-evoked data and resting-state correlations.

PubMed

Wig, Gagan S; Buckner, Randy L; Schacter, Daniel L

2009-05-01

Behavioral dissociations suggest that a single experience can separately influence multiple processing components. Here we used a repetition priming functional magnetic resonance imaging paradigm that directly contrasted the effects of stimulus and decision changes to identify the underlying brain systems. Direct repetition of stimulus features caused marked reductions in posterior regions of the inferior temporal lobe that were insensitive to whether the decision was held constant or changed between study and test. By contrast, prefrontal cortex showed repetition effects that were sensitive to the exact stimulus-to-decision mapping. Analysis of resting-state functional connectivity revealed that the dissociated repetition effects are embedded within distinct brain systems. Regions that were sensitive to changes in the stimulus correlated with perceptual cortices, whereas the decision changes attenuated activity in regions correlated with middle-temporal regions and a frontoparietal control system. These results thus explain the long-known dissociation between perceptual and conceptual components of priming by revealing how a single experience can separately influence distinct, concurrently active brain systems.

Neural correlates of long-term intense romantic love.

PubMed

Acevedo, Bianca P; Aron, Arthur; Fisher, Helen E; Brown, Lucy L

2012-02-01

The present study examined the neural correlates of long-term intense romantic love using functional magnetic resonance imaging (fMRI). Ten women and 7 men married an average of 21.4 years underwent fMRI while viewing facial images of their partner. Control images included a highly familiar acquaintance; a close, long-term friend; and a low-familiar person. Effects specific to the intensely loved, long-term partner were found in: (i) areas of the dopamine-rich reward and basal ganglia system, such as the ventral tegmental area (VTA) and dorsal striatum, consistent with results from early-stage romantic love studies; and (ii) several regions implicated in maternal attachment, such as the globus pallidus (GP), substantia nigra, Raphe nucleus, thalamus, insular cortex, anterior cingulate and posterior cingulate. Correlations of neural activity in regions of interest with widely used questionnaires showed: (i) VTA and caudate responses correlated with romantic love scores and inclusion of other in the self; (ii) GP responses correlated with friendship-based love scores; (iii) hypothalamus and posterior hippocampus responses correlated with sexual frequency; and (iv) caudate, septum/fornix, posterior cingulate and posterior hippocampus responses correlated with obsession. Overall, results suggest that for some individuals the reward-value associated with a long-term partner may be sustained, similar to new love, but also involves brain systems implicated in attachment and pair-bonding.

Neural correlates of long-term intense romantic love

PubMed Central

Aron, Arthur; Fisher, Helen E.; Brown, Lucy L.

2012-01-01

The present study examined the neural correlates of long-term intense romantic love using functional magnetic resonance imaging (fMRI). Ten women and 7 men married an average of 21.4 years underwent fMRI while viewing facial images of their partner. Control images included a highly familiar acquaintance; a close, long-term friend; and a low-familiar person. Effects specific to the intensely loved, long-term partner were found in: (i) areas of the dopamine-rich reward and basal ganglia system, such as the ventral tegmental area (VTA) and dorsal striatum, consistent with results from early-stage romantic love studies; and (ii) several regions implicated in maternal attachment, such as the globus pallidus (GP), substantia nigra, Raphe nucleus, thalamus, insular cortex, anterior cingulate and posterior cingulate. Correlations of neural activity in regions of interest with widely used questionnaires showed: (i) VTA and caudate responses correlated with romantic love scores and inclusion of other in the self; (ii) GP responses correlated with friendship-based love scores; (iii) hypothalamus and posterior hippocampus responses correlated with sexual frequency; and (iv) caudate, septum/fornix, posterior cingulate and posterior hippocampus responses correlated with obsession. Overall, results suggest that for some individuals the reward-value associated with a long-term partner may be sustained, similar to new love, but also involves brain systems implicated in attachment and pair-bonding. PMID:21208991

Correlations in star networks: from Bell inequalities to network inequalities

NASA Astrophysics Data System (ADS)

Tavakoli, Armin; Olivier Renou, Marc; Gisin, Nicolas; Brunner, Nicolas

2017-07-01

The problem of characterizing classical and quantum correlations in networks is considered. Contrary to the usual Bell scenario, where distant observers share a physical system emitted by one common source, a network features several independent sources, each distributing a physical system to a subset of observers. In the quantum setting, the observers can perform joint measurements on initially independent systems, which may lead to strong correlations across the whole network. In this work, we introduce a technique to systematically map a Bell inequality to a family of Bell-type inequalities bounding classical correlations on networks in a star-configuration. Also, we show that whenever a given Bell inequality can be violated by some entangled state ρ, then all the corresponding network inequalities can be violated by considering many copies of ρ distributed in the star network. The relevance of these ideas is illustrated by applying our method to a specific multi-setting Bell inequality. We derive the corresponding network inequalities, and study their quantum violations.

Metallothionein Induction as Indicator of Low Level Metal Exposure to Aquatic Macroinvertebrates from a Relatively Unimpacted River System in South Africa.

PubMed

Kemp, M; Wepener, V; de Kock, K N; Wolmarans, C T

2017-12-01

The Marico River is relatively unaffected by anthropogenic activities. However, metal concentrations-mainly from natural sources-occasionally exceed environmental quality guidelines. Macroinvertebrates are capable to react to these metals through processes such as the induction of metallothioneins (MTs). The aims of this study were to determine whether the induction of MTs can be used as indicator of natural metal exposure in not anthropogenically impacted systems and whether there are relationships between metal concentrations in water, sediment and macroinvertebrates and concomitant MT levels. Positive correlations were found between metals in sediment and macroinvertebrates, while there were no correlations between metal concentrations in water and macroinvertebrates. Even in a not anthropogenically impacted system, a positive correlation existed between trace metal bioaccumulation (e.g. Ni, Pb, Zn) in macroinvertebrates and the induction of MTs. There were, however, no correlations between MTs and bioaccumulation of earth metals (e.g. Al, Fe, Mn, Ti).

Systematic reviews: I. The correlation between laboratory tests on marginal quality and bond strength. II. The correlation between marginal quality and clinical outcome.

PubMed

Heintze, Siegward D

2007-01-01

An accepted principle in restorative dentistry states that restorations should be placed with the best marginal quality possible to avoid postoperative sensitivity, marginal discoloration, and secondary caries. Different laboratory methods claim to predict the clinical performance of restorative materials, for example, tests of bond strength and microleakage and gap analysis. The purpose of this review was twofold: (1) find studies that correlated the results of bond strength tests with either microleakage or gap analysis for the same materials, and (2) find studies that correlated the results of microleakage and/or gaps with the clinical parameters for the same materials. Furthermore, influencing factors on the results of the laboratory tests were reviewed and assessed. For the first question, searches for studies were conducted in the MEDLINE database and IADR/AADR abtracts online with specific search and inclusion criteria. The outcome for each study was assessed on the basis of the statistical test applied in the study, and finally the number of studies with or without correlation was compiled. For the second question, results of the quantitative marginal analysis of Class V restorations published by the University of Zürich with the same test protocol and prospective clinical trials were searched that investigated the same materials for at least 2 years in Class V cavities. Pearson correlation coefficients were calculated for pooled data of materials and clinical outcome parameters such as retention loss, marginal discoloration, marginal integrity, and secondary caries. For the correlation of dye penetration and clinical outcome, studies on Class V restorations published by the same research institute were searched in MEDLINE that examined the same adhesive systems as the selected clinical trials. For the correlation bond strength/microleakage, 30 studies were included into the review, and for the correlation bond strength/gap analysis 18 studies. For both topics, about 80% of the studies revealed that there was no correlation between the two methods. For the correlation quantitative marginal analysis/clinical outcome, data were compared to the clinical outcome of 11 selected clinical studies. In only 2 out of the 11 studies (18%) did the clinical outcome match the prognosis based on the laboratory tests; the remaining studies did not show any correlation. When pooling data on 20 adhesive systems, no correlation was found between the percentage of continuous margin of restorations placed in extracted premolars and the percentage of teeth that showed no retention loss in clinical studies, no discoloured margins, acceptable margins, or absence of secondary caries. With regard to the correlation of dye penetration and clinical studies, no sufficient number of studies was found that matched the inclusion criteria. However, literature data suggest that there is no correlation between microleakage data as measured in the laboratory and clinical parameters. The results of bond strength tests did not correlate with laboratory tests that evaluated the marginal seal of restorations such as microleakage or gap analysis. The quantitative marginal analysis of Class V fillings in the laboratory was unable to predict the performance of the same materials in vivo. Therefore, microleakage tests or the quantitative marginal analysis should be abandoned and research should focus on laboratory tests that are validated with regard to their ability to satisfactorily predict the clinical performance of restorative materials.

Design of pulse waveform for waveform division multiple access UWB wireless communication system.

PubMed

Yin, Zhendong; Wang, Zhirui; Liu, Xiaohui; Wu, Zhilu

2014-01-01

A new multiple access scheme, Waveform Division Multiple Access (WDMA) based on the orthogonal wavelet function, is presented. After studying the correlation properties of different categories of single wavelet functions, the one with the best correlation property will be chosen as the foundation for combined waveform. In the communication system, each user is assigned to different combined orthogonal waveform. Demonstrated by simulation, combined waveform is more suitable than single wavelet function to be a communication medium in WDMA system. Due to the excellent orthogonality, the bit error rate (BER) of multiuser with combined waveforms is so close to that of single user in a synchronous system. That is to say, the multiple access interference (MAI) is almost eliminated. Furthermore, even in an asynchronous system without multiuser detection after matched filters, the result is still pretty ideal and satisfactory by using the third combination mode that will be mentioned in the study.

Changes in Cross-Correlations as an Indicator for Systemic Risk

PubMed Central

Zheng, Zeyu; Podobnik, Boris; Feng, Ling; Li, Baowen

2012-01-01

The 2008–2012 global financial crisis began with the global recession in December 2007 and exacerbated in September 2008, during which the U.S. stock markets lost 20% of value from its October 11 2007 peak. Various studies reported that financial crisis are associated with increase in both cross-correlations among stocks and stock indices and the level of systemic risk. In this paper, we study 10 different Dow Jones economic sector indexes, and applying principle component analysis (PCA) we demonstrate that the rate of increase in principle components with short 12-month time windows can be effectively used as an indicator of systemic risk—the larger the change of PC1, the higher the increase of systemic risk. Clearly, the higher the level of systemic risk, the more likely a financial crisis would occur in the near future. PMID:23185692

Comparison of Solar and Wind Power Output and Correlation with Real-Time Pricing

NASA Astrophysics Data System (ADS)

Hoepfl, Kathryn E.; Compaan, Alvin D.; Solocha, Andrew

2011-03-01

This study presents a method that can be used to determine the least volatile power output of a wind and solar hybrid energy system in which wind and solar systems have the same peak power. Hourly data for wind and PV systems in Northwest Ohio are used to show that a combination of both types of sustainable energy sources produces a more stable power output and would be more valuable to the grid than either individually. This method could be used to determine the ideal ratio in any part of the country and should help convince electric utility companies to bring more renewable generation online. This study also looks at real-time market pricing and how each system (solar, wind, and hybrid) correlates with 2009 hourly pricing from the Midwest Interconnect. KEH acknowledges support from the NSF-REU grant PHY-1004649 to the Univ. of Toledo and Garland Energy Systems/Ohio Department of Development.

The Depressive Experiences Questionnaire: validity and psychological correlates in a clinical sample.

PubMed

Riley, W T; McCranie, E W

1990-01-01

This study sought to compare the original and revised scoring systems of the Depressive Experiences Questionnaire (DEQ) and to assess the construct validity of the Dependent and Self-Critical subscales of the DEQ in a clinically depressed sample. Subjects were 103 depressed inpatients who completed the DEQ, the Beck Depression Inventory (BDI), the Hopelessness Scale, the Automatic Thoughts Questionnaire (ATQ), the Rathus Assertiveness Schedule (RAS), and the Minnesota Multiphasic Personality Inventory (MMPI). The original and revised scoring systems of the DEQ evidenced good concurrent validity for each factor scale, but the revised system did not sufficiently discriminate dependent and self-critical dimensions. Using the original scoring system, self-criticism was significantly and positively related to severity of depression, whereas dependency was not, particularly for males. Factor analysis of the DEQ scales and the other scales used in this study supported the dependent and self-critical dimensions. For men, the correlation of the DEQ with the MMPI scales indicated that self-criticism was associated with psychotic symptoms, hostility/conflict, and a distress/exaggerated response set, whereas dependency did not correlate significantly with any MMPI scales. Females, however, did not exhibit a differential pattern of correlations between either the Dependency or the Self-Criticism scales and the MMPI. These findings suggest possible gender differences in the clinical characteristics of male and female dependent and self-critical depressive subtypes.

Expert systems for automated correlation and interpretation of wireline logs

USGS Publications Warehouse

Olea, R.A.

1994-01-01

CORRELATOR is an interactive computer program for lithostratigraphic correlation of wireline logs able to store correlations in a data base with a consistency, accuracy, speed, and resolution that are difficult to obtain manually. The automatic determination of correlations is based on the maximization of a weighted correlation coefficient using two wireline logs per well. CORRELATOR has an expert system to scan and flag incongruous correlations in the data base. The user has the option to accept or disregard the advice offered by the system. The expert system represents knowledge through production rules. The inference system is goal-driven and uses backward chaining to scan through the rules. Work in progress is used to illustrate the potential that a second expert system with a similar architecture for interpreting dip diagrams could have to identify episodes-as those of interest in sequence stratigraphy and fault detection- and annotate them in the stratigraphic column. Several examples illustrate the presentation. ?? 1994 International Association for Mathematical Geology.

Design of a Competency Evaluation Model for Clinical Nursing Practicum, Based on Standardized Language Systems: Psychometric Validation Study.

PubMed

Iglesias-Parra, Maria Rosa; García-Guerrero, Alfonso; García-Mayor, Silvia; Kaknani-Uttumchandani, Shakira; León-Campos, Álvaro; Morales-Asencio, José Miguel

2015-07-01

To develop an evaluation system of clinical competencies for the practicum of nursing students based on the Nursing Interventions Classification (NIC). Psychometric validation study: the first two phases addressed definition and content validation, and the third phase consisted of a cross-sectional study for analyzing reliability. The study population was undergraduate nursing students and clinical tutors. Through the Delphi technique, 26 competencies and 91 interventions were isolated. Cronbach's α was 0.96. Factor analysis yielded 18 factors that explained 68.82% of the variance. Overall inter-item correlation was 0.26, and total-item correlation ranged between 0.66 and 0.19. A competency system for the nursing practicum, structured on the NIC, is a reliable method for assessing and evaluating clinical competencies. Further evaluations in other contexts are needed. The availability of standardized language systems in the nursing discipline supposes an ideal framework to develop the nursing curricula. © 2015 Sigma Theta Tau International.

A Correlational Analysis of Strategic Information Systems Planning in K-12 Public Educational Organizations

ERIC Educational Resources Information Center

Martin, Christopher J.

2012-01-01

Three decades of research has indicated that strategic information systems planning is a vital component to business success. The purpose of this study was to identify the relationship strategic information systems planning and financial commitment has within the K-12 public education sector. Data for this study was obtained from top management of…

Work probability distribution for a ferromagnet with long-ranged and short-ranged correlations

NASA Astrophysics Data System (ADS)

Bhattacharjee, J. K.; Kirkpatrick, T. R.; Sengers, J. V.

2018-04-01

Work fluctuations and work probability distributions are fundamentally different in systems with short-ranged versus long-ranged correlations. Specifically, in systems with long-ranged correlations the work distribution is extraordinarily broad compared to systems with short-ranged correlations. This difference profoundly affects the possible applicability of fluctuation theorems like the Jarzynski fluctuation theorem. The Heisenberg ferromagnet, well below its Curie temperature, is a system with long-ranged correlations in very low magnetic fields due to the presence of Goldstone modes. As the magnetic field is increased the correlations gradually become short ranged. Hence, such a ferromagnet is an ideal system for elucidating the changes of the work probability distribution as one goes from a domain with long-ranged correlations to a domain with short-ranged correlations by tuning the magnetic field. A quantitative analysis of this crossover behavior of the work probability distribution and the associated fluctuations is presented.

Charge and spin correlations in the monopole liquid

NASA Astrophysics Data System (ADS)

Slobinsky, D.; Baglietto, G.; Borzi, R. A.

2018-05-01

A monopole liquid is a spin system with a high density of magnetic charges but no magnetic-charge order. We study such a liquid over an Ising pyrochlore lattice, where a single topological charge or monopole sits in each tetrahedron. Restricting the study to the case with no magnetic field applied we show that, in spite of the liquidlike correlations between charges imposed by construction constraints, the spins are uncorrelated like in a perfect paramagnet. We calculate a massive residual entropy for this phase (ln(2 )/2 , a result which is exact in the thermodynamic limit), implying a free Ising-like variable per tetrahedron. After defining a simple model Hamiltonian for this system (the balanced monopole liquid) we study its thermodynamics. Surprisingly, this monopole liquid remains a perfect paramagnet at all temperatures. Thermal disorder can then be simply and quantitatively interpreted as single charge dilution, by the excitation of neutral sites and double monopoles. The addition of the usual nearest neighbors interactions favoring neutral `2in-2out' excitations as a perturbation maintains the same ground state but induces short-range (topological) order by thermal disorder. While it decreases charge-charge correlations, pair spin correlations—resembling those in spin ice—appear on increasing temperature. This helps us to see in another light the dipolarlike correlations present in spin ices at unexpectedly high temperatures. On the other side, favoring double excitations strengthens the charges short range order and its associated spin correlations. Finally, we discuss how the monopole liquid can be related to other systems and materials where different phases of monopole matter have been observed.

Nonequilibrium steady states and resonant tunneling in time-periodically driven systems with interactions

NASA Astrophysics Data System (ADS)

Qin, Tao; Hofstetter, Walter

2018-03-01

Time-periodically driven systems are a versatile toolbox for realizing interesting effective Hamiltonians. Heating, caused by excitations to high-energy states, is a challenge for experiments. While most setups so far address the relatively weakly interacting regime, it is of general interest to study heating in strongly correlated systems. Using Floquet dynamical mean-field theory, we study nonequilibrium steady states (NESS) in the Falicov-Kimball model, with time-periodically driven kinetic energy or interaction. We systematically investigate the nonequilibrium properties of the NESS. For a driven kinetic energy, we show that resonant tunneling, where the interaction is an integer multiple of the driving frequency, plays an important role in the heating. In the strongly correlated regime, we show that this can be well understood using Fermi's golden rule and the Schrieffer-Wolff transformation for a time-periodically driven system. We furthermore demonstrate that resonant tunneling can be used to control the population of Floquet states to achieve "photodoping." For driven interactions introduced by an oscillating magnetic field near a widely adopted Feshbach resonance, we find that the double occupancy is strongly modulated. Our calculations apply to shaken ultracold-atom systems and to solid-state systems in a spatially uniform but time-dependent electric field. They are also closely related to lattice modulation spectroscopy. Our calculations are helpful to understand the latest experiments on strongly correlated Floquet systems.

Glenoid deformity in the coronal plane correlates with humeral head changes in osteoarthritis: a radiographic analysis.

PubMed

Hawi, Nael; Magosch, Petra; Tauber, Mark; Lichtenberg, Sven; Martetschläger, Frank; Habermeyer, Peter

2017-02-01

A variety of measurements can be used to assess radiographic osteoarthritic changes of the shoulder. This study aimed to analyze the correlation between the radiographic humeral-sided Samilson and Prieto classification system and 3 different radiographic classifications describing the changes of the glenoid in the coronal plane. The study material included standardized radiographs of 50 patients with idiopathic osteoarthritis before anatomic shoulder replacement. On the basis of radiographic measurements, the cases were evaluated using the Samilson and Prieto grading system, angle β, inclination type, and critical shoulder angle by 2 independent observers. Classification measurements showed an excellent agreement between observers. Our results showed that the humeral-sided Samilson and Prieto grading system had a statistically significant good correlation with angle β (observer 1, r = 0.74; observer 2, r = 0.77; P < .05) and a statistically significant excellent correlation with the inclination type of the glenoid (observer 1, r  = 0.86; observer 2, r = 0.8; P < .05). A poor correlation to the critical shoulder angle was observed (r = -0.14, r = 0.03; P > .05). The grade of humeral-sided osteoarthritis according to Samilson and Prieto correlates with the glenoid-sided osteoarthritic changes of the glenoid in the coronal plane described by the angle β and by the inclination type of the glenoid. Higher glenoid-sided inclination is associated with higher grade of osteoarthritis in primary shoulder osteoarthritis. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Community Detection for Correlation Matrices

NASA Astrophysics Data System (ADS)

MacMahon, Mel; Garlaschelli, Diego

2015-04-01

A challenging problem in the study of complex systems is that of resolving, without prior information, the emergent, mesoscopic organization determined by groups of units whose dynamical activity is more strongly correlated internally than with the rest of the system. The existing techniques to filter correlations are not explicitly oriented towards identifying such modules and can suffer from an unavoidable information loss. A promising alternative is that of employing community detection techniques developed in network theory. Unfortunately, this approach has focused predominantly on replacing network data with correlation matrices, a procedure that we show to be intrinsically biased because of its inconsistency with the null hypotheses underlying the existing algorithms. Here, we introduce, via a consistent redefinition of null models based on random matrix theory, the appropriate correlation-based counterparts of the most popular community detection techniques. Our methods can filter out both unit-specific noise and system-wide dependencies, and the resulting communities are internally correlated and mutually anticorrelated. We also implement multiresolution and multifrequency approaches revealing hierarchically nested subcommunities with "hard" cores and "soft" peripheries. We apply our techniques to several financial time series and identify mesoscopic groups of stocks which are irreducible to a standard, sectorial taxonomy; detect "soft stocks" that alternate between communities; and discuss implications for portfolio optimization and risk management.

Correlation as a Determinant of Configurational Entropy in Supramolecular and Protein Systems

PubMed Central

2015-01-01

For biomolecules in solution, changes in configurational entropy are thought to contribute substantially to the free energies of processes like binding and conformational change. In principle, the configurational entropy can be strongly affected by pairwise and higher-order correlations among conformational degrees of freedom. However, the literature offers mixed perspectives regarding the contributions that changes in correlations make to changes in configurational entropy for such processes. Here we take advantage of powerful techniques for simulation and entropy analysis to carry out rigorous in silico studies of correlation in binding and conformational changes. In particular, we apply information-theoretic expansions of the configurational entropy to well-sampled molecular dynamics simulations of a model host–guest system and the protein bovine pancreatic trypsin inhibitor. The results bear on the interpretation of NMR data, as they indicate that changes in correlation are important determinants of entropy changes for biologically relevant processes and that changes in correlation may either balance or reinforce changes in first-order entropy. The results also highlight the importance of main-chain torsions as contributors to changes in protein configurational entropy. As simulation techniques grow in power, the mathematical techniques used here will offer new opportunities to answer challenging questions about complex molecular systems. PMID:24702693

Pairing phase diagram of three holes in the generalized Hubbard model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Navarro, O.; Espinosa, J.E.

Investigations of high-{Tc} superconductors suggest that the electronic correlation may play a significant role in the formation of pairs. Although the main interest is on the physic of two-dimensional highly correlated electron systems, the one-dimensional models related to high temperature superconductivity are very popular due to the conjecture that properties of the 1D and 2D variants of certain models have common aspects. Within the models for correlated electron systems, that attempt to capture the essential physics of high-temperature superconductors and parent compounds, the Hubbard model is one of the simplest. Here, the pairing problem of a three electrons system hasmore » been studied by using a real-space method and the generalized Hubbard Hamiltonian. This method includes the correlated hopping interactions as an extension of the previously proposed mapping method, and is based on mapping the correlated many body problem onto an equivalent site- and bond-impurity tight-binding one in a higher dimensional space, where the problem was solved in a non-perturbative way. In a linear chain, the authors analyzed the pairing phase diagram of three correlated holes for different values of the Hamiltonian parameters. For some value of the hopping parameters they obtain an analytical solution for all kind of interactions.« less

Y balance test has no correlation with the Stability Index of the Biodex Balance System.

PubMed

Almeida, Gabriel Peixoto Leão; Monteiro, Isabel Oliveira; Marizeiro, Débora Fortes; Maia, Laísa Braga; de Paula Lima, Pedro Olavo

2017-02-01

A cross-sectional study design. The Stability Index of the Biodex Balance System (SI-BBS) and Y Balance Test (YBT) has been used in studies assessing postural stability but no studies have verified the association of the YBT with the SI-BBS. To analyze the association of the Y Balance Test (YBT) with the Stability Index of the Biodex Balance System (SI-BBS) to evaluate postural stability. Forty participants who engaged in recreational physical activities, 12 of whom had a history of injury to the lower limbs. Was used the SI-BBS and the anterior, posterolateral, posteromedial, and composite measures of the YBT. The order of execution of the tests and of the lower limbs evaluated was randomized and blind tested by two evaluators. Pearson's correlation coefficient was used to check the strength of the relationship between the distances achieved on the YBT and the SI-BBS. The YBT showed excellent reliability in the anterior, posteromedial, and posterolateral directions. However, the YBT showed no statistically significant correlation with any variables in the SI-BBS, indicating poor validity between YBT and SI-BBS assessments of postural stability in people with and without history of lower limb injuries. The results of this study showed the YBT is not correlated with the SI-BBS as an assessment of postural stability. This finding has implications for researchers and clinicians using YBT results as the only measure of postural stability. Copyright © 2016 Elsevier Ltd. All rights reserved.

Report on the Study of Radiation Damage in Calcium Fluoride and Magnesium Fluoride Crystals for use in Excimer Laser Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

None, None

1999-10-04

A study was performed to investigate the effects of radiation damage in calcium fluoride and magnesium fluoride crystals caused by gamma rays and UV photons from excimer lasers. The purpose was to study and correlate the damage caused by these two different mechanisms in various types of material used for fabricating optical elements in high power excimer lasers and lens systems of lithography tools. These optical systems are easily damaged by the laser itself, and it is necessary to use only the most radiation resistant materials for certain key elements. It was found that a clear correlation exists between the,more » radiation induced damage caused by high energy gamma rays and that produced by UV photons from the excimer laser. This correlation allows a simple procedure to be developed to select the most radiation resistant material at the ingot level, which would be later used to fabricate various components of the optical system. This avoids incurring the additional cost of fabricating actual optical elements with material that would later be damaged under prolonged use. The result of this screening procedure can result in a considerable savings in the overall cost of the lens and laser system.« less

Synchronization in human musical rhythms and mutually interacting complex systems

PubMed Central

Hennig, Holger

2014-01-01

Though the music produced by an ensemble is influenced by multiple factors, including musical genre, musician skill, and individual interpretation, rhythmic synchronization is at the foundation of musical interaction. Here, we study the statistical nature of the mutual interaction between two humans synchronizing rhythms. We find that the interbeat intervals of both laypeople and professional musicians exhibit scale-free (power law) cross-correlations. Surprisingly, the next beat to be played by one person is dependent on the entire history of the other person’s interbeat intervals on timescales up to several minutes. To understand this finding, we propose a general stochastic model for mutually interacting complex systems, which suggests a physiologically motivated explanation for the occurrence of scale-free cross-correlations. We show that the observed long-term memory phenomenon in rhythmic synchronization can be imitated by fractal coupling of separately recorded or synthesized audio tracks and thus applied in electronic music. Though this study provides an understanding of fundamental characteristics of timing and synchronization at the interbrain level, the mutually interacting complex systems model may also be applied to study the dynamics of other complex systems where scale-free cross-correlations have been observed, including econophysics, physiological time series, and collective behavior of animal flocks. PMID:25114228

Algorithmic implementation of particle-particle ladder diagram approximation to study strongly-correlated metals and semiconductors

NASA Astrophysics Data System (ADS)

Prayogi, A.; Majidi, M. A.

2017-07-01

In condensed-matter physics, strongly-correlated systems refer to materials that exhibit variety of fascinating properties and ordered phases, depending on temperature, doping, and other factors. Such unique properties most notably arise due to strong electron-electron interactions, and in some cases due to interactions involving other quasiparticles as well. Electronic correlation effects are non-trivial that one may need a sufficiently accurate approximation technique with quite heavy computation, such as Quantum Monte-Carlo, in order to capture particular material properties arising from such effects. Meanwhile, less accurate techniques may come with lower numerical cost, but the ability to capture particular properties may highly depend on the choice of approximation. Among the many-body techniques derivable from Feynman diagrams, we aim to formulate algorithmic implementation of the Ladder Diagram approximation to capture the effects of electron-electron interactions. We wish to investigate how these correlation effects influence the temperature-dependent properties of strongly-correlated metals and semiconductors. As we are interested to study the temperature-dependent properties of the system, the Ladder diagram method needs to be applied in Matsubara frequency domain to obtain the self-consistent self-energy. However, at the end we would also need to compute the dynamical properties like density of states (DOS) and optical conductivity that are defined in the real frequency domain. For this purpose, we need to perform the analytic continuation procedure. At the end of this study, we will test the technique by observing the occurrence of metal-insulator transition in strongly-correlated metals, and renormalization of the band gap in strongly-correlated semiconductors.

Electronic Structures of Anti-Ferromagnetic Tetraradicals: Ab Initio and Semi-Empirical Studies.

PubMed

Zhang, Dawei; Liu, Chungen

2016-04-12

The energy relationships and electronic structures of the lowest-lying spin states in several anti-ferromagnetic tetraradical model systems are studied with high-level ab initio and semi-empirical methods. The Full-CI method (FCI), the complete active space second-order perturbation theory (CASPT2), and the n-electron valence state perturbation theory (NEVPT2) are employed to obtain reference results. By comparing the energy relationships predicted from the Heisenberg and Hubbard models with ab initio benchmarks, the accuracy of the widely used Heisenberg model for anti-ferromagnetic spin-coupling in low-spin polyradicals is cautiously tested in this work. It is found that the strength of electron correlation (|U/t|) concerning anti-ferromagnetically coupled radical centers could range widely from strong to moderate correlation regimes and could become another degree of freedom besides the spin multiplicity. Accordingly, the Heisenberg-type model works well in the regime of strong correlation, which reproduces well the energy relationships along with the wave functions of all the spin states. In moderately spin-correlated tetraradicals, the results of the prototype Heisenberg model deviate severely from those of multi-reference electron correlation ab initio methods, while the extended Heisenberg model, containing four-body terms, can introduce reasonable corrections and maintains its accuracy in this condition. In the weak correlation regime, both the prototype Heisenberg model and its extended forms containing higher-order correction terms will encounter difficulties. Meanwhile, the Hubbard model shows balanced accuracy from strong to weak correlation cases and can reproduce qualitatively correct electronic structures, which makes it more suitable for the study of anti-ferromagnetic coupling in polyradical systems.

GeoBioScience: Red Wood Ants as Bioindicators for Active Tectonic Fault Systems in the West Eifel (Germany)

PubMed Central

Berberich, Gabriele; Schreiber, Ulrich

2013-01-01

Simple Summary In a 1.140 km² study area of the volcanic West Eifel, approx. 3,000 Red Wood Ant (RWA; Formica rufa-group) mounds had been identified and correlated with tectonically active gas-permeable faults, mostly strike-slip faults. Linear alignment of RWA mounds and soil gas anomalies distinctly indicate the course of these faults, while clusters of mounds indicate crosscut zones of fault systems, which can be correlated with voids caused by crustal block rotation. This demonstrates that RWA are bioindicators for identifying active fault systems and useful where information on the active regime is incomplete or the resolution by technical means is insufficient. Abstract In a 1.140 km² study area of the volcanic West Eifel, a comprehensive investigation established the correlation between red wood ant mound (RWA; Formica rufa-group) sites and active tectonic faults. The current stress field with a NW-SE-trending main stress direction opens pathways for geogenic gases and potential magmas following the same orientation. At the same time, Variscan and Mesozoic fault zones are reactivated. The results showed linear alignments and clusters of approx. 3,000 RWA mounds. While linear mound distribution correlate with strike-slip fault systems documented by quartz and ore veins and fault planes with slickensides, the clusters represent crosscut zones of dominant fault systems. Latter can be correlated with voids caused by crustal block rotation. Gas analyses from soil air, mineral springs and mofettes (CO2, Helium, Radon and H2S) reveal limiting concentrations for the spatial distribution of mounds and colonization. Striking is further the almost complete absence of RWA mounds in the core area of the Quaternary volcanic field. A possible cause can be found in occasionally occurring H2S in the fault systems, which is toxic at miniscule concentrations to the ants. Viewed overall, there is a strong relationship between RWA mounds and active tectonics in the West Eifel. PMID:26487413

Immunohistochemical expression of p53 and its clinicopathological correlation with modified Anneroth's histological grading system.

PubMed

Dave, Kajal V; Chalishazar, Monali; Dave, Vishal R; Panja, Pritam; Singh, Manisha; Modi, Tapan G

2016-01-01

Oral squamous cell carcinoma (OSCC) is an epithelial neoplasm generally beginning as focal overgrowth of altered stem cells near the basement membrane, moving upward and laterally, replacing the normal epithelium. Histopathological grading has been used for many decades in an attempt to predict the clinical behavior of oral squamous cell carcinoma. In the present study, Forty biopsies were studied for histological grading and p53 expression. The p53 expression was studied in relation to clinical parameters such as age, sex of patient and site of tumors. Relation between histological grade of malignancy and p53 protein expression was analysed. All cases were classified according to Anneroth's histological malignancy grading system (1987). 40 cases of OSCC were assessed for clinical parameters, Anneroth's histological grading and immunohistochemically stained with p53 protien. The results obtained were analyzed using Spearman's Co-relation. The positive expression of p53 was found in 62% of carcinomas studied. Positivity of p53 showed correlation with histological grade of malignancy and with individual parameters like degree of keratinization, nuclear polymorphism, number of mitoses and lymphoplasmacytic infiltration while showed a negative correlation with pattern of invasion. Our study showed a significant correlation between parameters of tumor cell population, lymphoplasmacytic infiltration and p53 expression. A significant association between high grade of malignancy and p53 overexpression and insignificant correlation of p53 with age, sex of the patient and site of the tumor was found.

Dominating clasp of the financial sector revealed by partial correlation analysis of the stock market.

PubMed

Kenett, Dror Y; Tumminello, Michele; Madi, Asaf; Gur-Gershgoren, Gitit; Mantegna, Rosario N; Ben-Jacob, Eshel

2010-12-20

What are the dominant stocks which drive the correlations present among stocks traded in a stock market? Can a correlation analysis provide an answer to this question? In the past, correlation based networks have been proposed as a tool to uncover the underlying backbone of the market. Correlation based networks represent the stocks and their relationships, which are then investigated using different network theory methodologies. Here we introduce a new concept to tackle the above question--the partial correlation network. Partial correlation is a measure of how the correlation between two variables, e.g., stock returns, is affected by a third variable. By using it we define a proxy of stock influence, which is then used to construct partial correlation networks. The empirical part of this study is performed on a specific financial system, namely the set of 300 highly capitalized stocks traded at the New York Stock Exchange, in the time period 2001-2003. By constructing the partial correlation network, unlike the case of standard correlation based networks, we find that stocks belonging to the financial sector and, in particular, to the investment services sub-sector, are the most influential stocks affecting the correlation profile of the system. Using a moving window analysis, we find that the strong influence of the financial stocks is conserved across time for the investigated trading period. Our findings shed a new light on the underlying mechanisms and driving forces controlling the correlation profile observed in a financial market.

Self-adaptive tensor network states with multi-site correlators

NASA Astrophysics Data System (ADS)

Kovyrshin, Arseny; Reiher, Markus

2017-12-01

We introduce the concept of self-adaptive tensor network states (SATNSs) based on multi-site correlators. The SATNS ansatz gradually extends its variational space incorporating the most important next-order correlators into the ansatz for the wave function. The selection of these correlators is guided by entanglement-entropy measures from quantum information theory. By sequentially introducing variational parameters and adjusting them to the system under study, the SATNS ansatz achieves keeping their number significantly smaller than the total number of full-configuration interaction parameters. The SATNS ansatz is studied for manganocene in its lowest-energy sextet and doublet states; the latter of which is known to be difficult to describe. It is shown that the SATNS parametrization solves the convergence issues found for previous correlator-based tensor network states.

Lieb-Robinson bounds on n -partite connected correlation functions

NASA Astrophysics Data System (ADS)

Tran, Minh Cong; Garrison, James R.; Gong, Zhe-Xuan; Gorshkov, Alexey V.

2017-11-01

Lieb and Robinson provided bounds on how fast bipartite connected correlations can arise in systems with only short-range interactions. We generalize Lieb-Robinson bounds on bipartite connected correlators to multipartite connected correlators. The bounds imply that an n -partite connected correlator can reach unit value in constant time. Remarkably, the bounds also allow for an n -partite connected correlator to reach a value that is exponentially large with system size in constant time, a feature which stands in contrast to bipartite connected correlations. We provide explicit examples of such systems.

Nonlinear waves in reaction-diffusion systems: The effect of transport memory

NASA Astrophysics Data System (ADS)

Manne, K. K.; Hurd, A. J.; Kenkre, V. M.

2000-04-01

Motivated by the problem of determining stress distributions in granular materials, we study the effect of finite transport correlation times on the propagation of nonlinear wave fronts in reaction-diffusion systems. We obtain results such as the possibility of spatial oscillations in the wave-front shape for certain values of the system parameters and high enough wave-front speeds. We also generalize earlier known results concerning the minimum wave-front speed and shape-speed relationships stemming from the finiteness of the correlation times. Analytic investigations are made possible by a piecewise linear representation of the nonlinearity.

Rheological behavior of FM-9 solutions and correlation with flammability test results and interpretations. [fuel thickening additive

NASA Technical Reports Server (NTRS)

Peng, S. T. J.; Landel, R. F.

1983-01-01

The rheological behavior of progressively shear thickening FM-9 solutions, a time-dependent shear thickening material with characteristics of threshold behavior, is investigated as part of a study of the rheological properties of antimisting jet fuel. Flammability test results and test configurations from various sources are evaluated. A correlation is obtained between the rheological behavior and the flammability tests such that, for a given system, such as a fixed solvent system and the FM-9 polymer system, the flammability criterion can be applied to a wide range of concentrations and temperatures.

Retinal nerve fiber layer thickness and neuropsychiatric manifestations in systemic lupus erythematosus.

PubMed

Shulman, S; Shorer, R; Wollman, J; Dotan, G; Paran, D

2017-11-01

Background Cognitive impairment is frequent in systemic lupus erythematosus. Atrophy of the corpus callosum and hippocampus have been reported in patients with systemic lupus erythematosus, and diffusion tensor imaging studies have shown impaired white matter integrity, suggesting that white matter damage in systemic lupus erythematosus may underlie the cognitive impairment as well as other neuropsychiatric systemic lupus erythematosus manifestations. Retinal nerve fiber layer thickness, as assessed by optical coherence tomography, has been suggested as a biomarker for white matter damage in neurologic disorders such as multiple sclerosis, Alzheimer's disease and Parkinson's disease. Retinal nerve fiber layer thinning may occur early, even in patients with mild clinical symptoms. Aim The objective of this study was to assess the association of retinal nerve fiber layer thickness, as a biomarker of white matter damage in systemic lupus erythematosus patients, with neuropsychiatric systemic lupus erythematosus manifestations, including cognitive impairment. Methods Twenty-one consecutive patients with systemic lupus erythematosus underwent neuropsychological testing using a validated computerized battery of tests as well as the Rey-Auditory verbal learning test. All 21 patients, as well as 11 healthy, age matched controls, underwent optical coherence tomography testing to assess retinal nerve fiber layer thickness. Correlations between retinal nerve fiber layer thickness and results in eight cognitive domains assessed by the computerized battery of tests as well as the Rey-Auditory verbal learning test were assessed in patients with systemic lupus erythematosus, with and without neuropsychiatric systemic lupus erythematosus, and compared to retinal nerve fiber layer thickness in healthy controls. Results No statistically significant correlation was found between retinal nerve fiber layer thickness in patients with systemic lupus erythematosus as compared to healthy controls. When evaluating by subgroups, no correlation was found between patients with or without neuropsychiatric systemic lupus erythematosus or cognitive impairment and retinal nerve fiber layer thickness. Conclusion Retinal nerve fiber layer thickness of systemic lupus erythematosus patients was not found to be statistically different compared to controls. Within systemic lupus erythematosus patients there was no correlation between retinal nerve fiber layer thickness and cognitive impairment or other neuropsychiatric systemic lupus erythematosus manifestations.

High-Stakes & Assessment Innovation: A Negative Correlation? Research Report.

ERIC Educational Resources Information Center

Ananda, Sri; Rabinowitz, Stanley

This paper makes the case that, as implemented so far, there has been an inverse correlation between innovation and accountability in statewide assessment systems. The higher the stakes attached to the assessment results, the more conservative the assessment methodology ultimately used. Case studies of two state assessment programs were carried…

Country-Level Correlates of Educational Achievement: Evidence from Large-Scale Surveys

ERIC Educational Resources Information Center

He, Jia; Van de Vijver, Fons J. R.; Kulikova, Alena

2017-01-01

Linking country-level educational achievement with other country-level indicators has the potential to drive systemic educational changes, as these correlates may reflect characteristics relevant for policy-making decisions to improve educational effectiveness. This study establishes a nomological network of educational achievement at the country…

Neural Correlates of Sublexical Processing in Phonological Working Memory

ERIC Educational Resources Information Center

McGettigan, Carolyn; Warren, Jane E.; Eisner, Frank; Marshall, Chloe R.; Shanmugalingam, Pradheep; Scott, Sophie K.

2011-01-01

This study investigated links between working memory and speech processing systems. We used delayed pseudoword repetition in fMRI to investigate the neural correlates of sublexical structure in phonological working memory (pWM). We orthogonally varied the number of syllables and consonant clusters in auditory pseudowords and measured the neural…

Correlation matrix renormalization theory for correlated-electron materials with application to the crystalline phases of atomic hydrogen

DOE PAGES

Zhao, Xin; Liu, Jun; Yao, Yong-Xin; ...

2018-01-23

Developing accurate and computationally efficient methods to calculate the electronic structure and total energy of correlated-electron materials has been a very challenging task in condensed matter physics and materials science. Recently, we have developed a correlation matrix renormalization (CMR) method which does not assume any empirical Coulomb interaction U parameters and does not have double counting problems in the ground-state total energy calculation. The CMR method has been demonstrated to be accurate in describing both the bonding and bond breaking behaviors of molecules. In this study, we extend the CMR method to the treatment of electron correlations in periodic solidmore » systems. By using a linear hydrogen chain as a benchmark system, we show that the results from the CMR method compare very well with those obtained recently by accurate quantum Monte Carlo (QMC) calculations. We also study the equation of states of three-dimensional crystalline phases of atomic hydrogen. We show that the results from the CMR method agree much better with the available QMC data in comparison with those from density functional theory and Hartree-Fock calculations.« less

Correlation matrix renormalization theory for correlated-electron materials with application to the crystalline phases of atomic hydrogen

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Xin; Liu, Jun; Yao, Yong-Xin

Developing accurate and computationally efficient methods to calculate the electronic structure and total energy of correlated-electron materials has been a very challenging task in condensed matter physics and materials science. Recently, we have developed a correlation matrix renormalization (CMR) method which does not assume any empirical Coulomb interaction U parameters and does not have double counting problems in the ground-state total energy calculation. The CMR method has been demonstrated to be accurate in describing both the bonding and bond breaking behaviors of molecules. In this study, we extend the CMR method to the treatment of electron correlations in periodic solidmore » systems. By using a linear hydrogen chain as a benchmark system, we show that the results from the CMR method compare very well with those obtained recently by accurate quantum Monte Carlo (QMC) calculations. We also study the equation of states of three-dimensional crystalline phases of atomic hydrogen. We show that the results from the CMR method agree much better with the available QMC data in comparison with those from density functional theory and Hartree-Fock calculations.« less

[The link between periodontitis and pancreatic cancer - review of the literature].

PubMed

Haładyj, Anna; Kaczyński, Tomasz; Górska, Renata

2016-01-01

Recent studies suggest that there is a plausible correlation between periodontitis and its influence on general health. By increasing systemic inflammatory response, which does not expire as long as inflammation of periodontal tissue endures, periodontal diseases may induce the increased risk of systemic diseases. Studies found a positive correlation between periodontitis and its impact on development of pancreatic cancer. The relationship between inflammatory periodontal disease and an increased risk of pancreatic cancer is not yet fully understood, therefore, further researches are warranted. The paper discusses the potential mechanisms that combine both entities and affect each other. It also presents results of recent studies showing a link between periodontitis and an increased risk of pancreatic cancer.

Thermodynamics of pairing in mesoscopic systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sumaryada, Tony; Volya, Alexander

Using numerical and analytical methods implemented for different models, we conduct a systematic study of the thermodynamic properties of pairing correlations in mesoscopic nuclear systems. Various quantities are calculated and analyzed using the exact solution of pairing. An in-depth comparison of canonical, grand canonical, and microcanonical ensembles is conducted. The nature of the pairing phase transition in a small system is of a particular interest. We discuss the onset of discontinuity in the thermodynamic variables, fluctuations, and evolution of zeros of the canonical and grand canonical partition functions in the complex plane. The behavior of the invariant correlational entropy ismore » also studied in the transitional region of interest. The change in the character of the phase transition due to the presence of a magnetic field is discussed along with studies of superconducting thermodynamics.« less

A novel way to detect correlations on multi-time scales, with temporal evolution and for multi-variables

NASA Astrophysics Data System (ADS)

Yuan, Naiming; Xoplaki, Elena; Zhu, Congwen; Luterbacher, Juerg

2016-06-01

In this paper, two new methods, Temporal evolution of Detrended Cross-Correlation Analysis (TDCCA) and Temporal evolution of Detrended Partial-Cross-Correlation Analysis (TDPCCA), are proposed by generalizing DCCA and DPCCA. Applying TDCCA/TDPCCA, it is possible to study correlations on multi-time scales and over different periods. To illustrate their properties, we used two climatological examples: i) Global Sea Level (GSL) versus North Atlantic Oscillation (NAO); and ii) Summer Rainfall over Yangtze River (SRYR) versus previous winter Pacific Decadal Oscillation (PDO). We find significant correlations between GSL and NAO on time scales of 60 to 140 years, but the correlations are non-significant between 1865-1875. As for SRYR and PDO, significant correlations are found on time scales of 30 to 35 years, but the correlations are more pronounced during the recent 30 years. By combining TDCCA/TDPCCA and DCCA/DPCCA, we proposed a new correlation-detection system, which compared to traditional methods, can objectively show how two time series are related (on which time scale, during which time period). These are important not only for diagnosis of complex system, but also for better designs of prediction models. Therefore, the new methods offer new opportunities for applications in natural sciences, such as ecology, economy, sociology and other research fields.

Observations and modeling of the ionospheric gravity and diamagnetic current systems from CHAMP and Swarm measurements

NASA Astrophysics Data System (ADS)

Alken, P.

2016-01-01

The CHAMP and Swarm satellites, which provide high-quality magnetic field measurements in low-altitude polar orbits, are ideally suited for investigating ionospheric current systems. In this study, we focus on the F region low-latitude gravity and diamagnetic currents which are prominent in the equatorial ionization anomaly (EIA) region in the North and South Hemisphere. During its 10 year mission, CHAMP has sampled nearly the entire altitude range of the EIA, offering the opportunity to study these currents from above, inside, and below their source region. The Swarm constellation offers the unique opportunity to study near-simultaneous measurements of the current systems at different longitudinal separations. In this study, we present new observations of these current systems, investigate their seasonal and local time dependence, investigate the use of in situ electron density measurements as a proxy for the magnetic perturbations, and compute the longitudinal self correlation of these currents. We find that these currents are strongest during spring and fall, produce nighttime magnetic fields at satellite altitude of up to 5-7 nT during solar maximum, 2-3 nT during solar minimum, and are highly correlated with in situ electron density measurements. We also find these currents are self-correlated above 70% up to 15° longitude in both hemispheres during the evening.

Canine sterile nodular panniculitis: a retrospective study of 39 dogs.

PubMed

Contreary, Caitlin L; Outerbridge, Catherine A; Affolter, Verena K; Kass, Philip H; White, Stephen D

2015-12-01

Canine sterile nodular panniculitis (SNP) is an inflammatory disease of the panniculus that is typically managed with immunomodulatory or immunosuppressive treatments. It has been reported to be a cutaneous marker of an underlying systemic disease. To assess the presence or absence of concurrent systemic diseases associated with canine SNP and to document breed predispositions. Thirty nine dogs presented to a veterinary teaching hospital from 1990 to 2012 which met inclusion criteria. Inclusion in this retrospective study required a diagnosis of SNP via histopathological analysis and negative special stains for infectious organisms. Breed distributions of affected dogs were compared to all other dogs examined at this hospital during the study period. Correlations between the histological pattern of panniculitis and the histological presence of dermatitis, clinical presentation of lesions, dog breed and therapeutic outcomes were assessed. Australian shepherd dogs, Brittany spaniels, Dalmatians, Pomeranians and Chihuahuas were significantly over-represented, but correlations between inflammatory patterns of panniculitis and other histological and clinical factors were not identified. Based on the information available in medical records, 32 dogs (82.1%) had no concurrent systemic diseases identified. Four dogs had concurrent polyarthritis, which may be related to SNP through unknown mechanisms. This study identified several novel breed predilections for SNP; it failed to find any clear correlations with associated systemic diseases other than polyarthritis. The histological inflammatory pattern of SNP does not predict therapeutic outcome. © 2015 ESVD and ACVD.

Decorrelation of Neural-Network Activity by Inhibitory Feedback

PubMed Central

Einevoll, Gaute T.; Diesmann, Markus

2012-01-01

Correlations in spike-train ensembles can seriously impair the encoding of information by their spatio-temporal structure. An inevitable source of correlation in finite neural networks is common presynaptic input to pairs of neurons. Recent studies demonstrate that spike correlations in recurrent neural networks are considerably smaller than expected based on the amount of shared presynaptic input. Here, we explain this observation by means of a linear network model and simulations of networks of leaky integrate-and-fire neurons. We show that inhibitory feedback efficiently suppresses pairwise correlations and, hence, population-rate fluctuations, thereby assigning inhibitory neurons the new role of active decorrelation. We quantify this decorrelation by comparing the responses of the intact recurrent network (feedback system) and systems where the statistics of the feedback channel is perturbed (feedforward system). Manipulations of the feedback statistics can lead to a significant increase in the power and coherence of the population response. In particular, neglecting correlations within the ensemble of feedback channels or between the external stimulus and the feedback amplifies population-rate fluctuations by orders of magnitude. The fluctuation suppression in homogeneous inhibitory networks is explained by a negative feedback loop in the one-dimensional dynamics of the compound activity. Similarly, a change of coordinates exposes an effective negative feedback loop in the compound dynamics of stable excitatory-inhibitory networks. The suppression of input correlations in finite networks is explained by the population averaged correlations in the linear network model: In purely inhibitory networks, shared-input correlations are canceled by negative spike-train correlations. In excitatory-inhibitory networks, spike-train correlations are typically positive. Here, the suppression of input correlations is not a result of the mere existence of correlations between excitatory (E) and inhibitory (I) neurons, but a consequence of a particular structure of correlations among the three possible pairings (EE, EI, II). PMID:23133368

Correlation between mass transfer coefficient kLa and relevant operating parameters in cylindrical disposable shaken bioreactors on a bench-to-pilot scale

PubMed Central

2013-01-01

Background Among disposable bioreactor systems, cylindrical orbitally shaken bioreactors show important advantages. They provide a well-defined hydrodynamic flow combined with excellent mixing and oxygen transfer for mammalian and plant cell cultivations. Since there is no known universal correlation between the volumetric mass transfer coefficient for oxygen kLa and relevant operating parameters in such bioreactor systems, the aim of this current study is to experimentally determine a universal kLa correlation. Results A Respiration Activity Monitoring System (RAMOS) was used to measure kLa values in cylindrical disposable shaken bioreactors and Buckingham’s π-Theorem was applied to define a dimensionless equation for kLa. In this way, a scale- and volume-independent kLa correlation was developed and validated in bioreactors with volumes from 2 L to 200 L. The final correlation was used to calculate cultivation parameters at different scales to allow a sufficient oxygen supply of tobacco BY-2 cell suspension cultures. Conclusion The resulting equation can be universally applied to calculate the mass transfer coefficient for any of seven relevant cultivation parameters such as the reactor diameter, the shaking frequency, the filling volume, the viscosity, the oxygen diffusion coefficient, the gravitational acceleration or the shaking diameter within an accuracy range of +/− 30%. To our knowledge, this is the first kLa correlation that has been defined and validated for the cited bioreactor system on a bench-to-pilot scale. PMID:24289110

Correlation between mass transfer coefficient kLa and relevant operating parameters in cylindrical disposable shaken bioreactors on a bench-to-pilot scale.

PubMed

Klöckner, Wolf; Gacem, Riad; Anderlei, Tibor; Raven, Nicole; Schillberg, Stefan; Lattermann, Clemens; Büchs, Jochen

2013-12-02

Among disposable bioreactor systems, cylindrical orbitally shaken bioreactors show important advantages. They provide a well-defined hydrodynamic flow combined with excellent mixing and oxygen transfer for mammalian and plant cell cultivations. Since there is no known universal correlation between the volumetric mass transfer coefficient for oxygen kLa and relevant operating parameters in such bioreactor systems, the aim of this current study is to experimentally determine a universal kLa correlation. A Respiration Activity Monitoring System (RAMOS) was used to measure kLa values in cylindrical disposable shaken bioreactors and Buckingham's π-Theorem was applied to define a dimensionless equation for kLa. In this way, a scale- and volume-independent kLa correlation was developed and validated in bioreactors with volumes from 2 L to 200 L. The final correlation was used to calculate cultivation parameters at different scales to allow a sufficient oxygen supply of tobacco BY-2 cell suspension cultures. The resulting equation can be universally applied to calculate the mass transfer coefficient for any of seven relevant cultivation parameters such as the reactor diameter, the shaking frequency, the filling volume, the viscosity, the oxygen diffusion coefficient, the gravitational acceleration or the shaking diameter within an accuracy range of +/- 30%. To our knowledge, this is the first kLa correlation that has been defined and validated for the cited bioreactor system on a bench-to-pilot scale.

Evidence for Collective Multiparticle Correlations in p -Pb Collisions

NASA Astrophysics Data System (ADS)

Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; Erö, J.; Friedl, M.; Frühwirth, R.; Ghete, V. M.; Hartl, C.; Hörmann, N.; Hrubec, J.; Jeitler, M.; Kiesenhofer, W.; Knünz, V.; Krammer, M.; Krätschmer, I.; Liko, D.; Mikulec, I.; Rabady, D.; Rahbaran, B.; Rohringer, H.; Schöfbeck, R.; Strauss, J.; Treberer-Treberspurg, W.; Waltenberger, W.; Wulz, C.-E.; Mossolov, V.; Shumeiko, N.; Suarez Gonzalez, J.; Alderweireldt, S.; Bansal, S.; Cornelis, T.; De Wolf, E. A.; Janssen, X.; Knutsson, A.; Lauwers, J.; Luyckx, S.; Ochesanu, S.; Rougny, R.; Van De Klundert, M.; Van Haevermaet, H.; Van Mechelen, P.; Van Remortel, N.; Van Spilbeeck, A.; Blekman, F.; Blyweert, S.; D'Hondt, J.; Daci, N.; Heracleous, N.; Keaveney, J.; Lowette, S.; Maes, M.; Olbrechts, A.; Python, Q.; Strom, D.; Tavernier, S.; Van Doninck, W.; Van Mulders, P.; Van Onsem, G. P.; Villella, I.; Caillol, C.; Clerbaux, B.; De Lentdecker, G.; Dobur, D.; Favart, L.; Gay, A. P. R.; Grebenyuk, A.; Léonard, A.; Mohammadi, A.; Perniè, L.; Randle-conde, A.; Reis, T.; Seva, T.; Thomas, L.; Vander Velde, C.; Vanlaer, P.; Wang, J.; Zenoni, F.; Adler, V.; Beernaert, K.; Benucci, L.; Cimmino, A.; Costantini, S.; Crucy, S.; Fagot, A.; Garcia, G.; Mccartin, J.; Ocampo Rios, A. A.; Poyraz, D.; Ryckbosch, D.; Salva Diblen, S.; Sigamani, M.; Strobbe, N.; Thyssen, F.; Tytgat, M.; Yazgan, E.; Zaganidis, N.; Basegmez, S.; Beluffi, C.; Bruno, G.; Castello, R.; Caudron, A.; Ceard, L.; Da Silveira, G. G.; Delaere, C.; du Pree, T.; Favart, D.; Forthomme, L.; Giammanco, A.; Hollar, J.; Jafari, A.; Jez, P.; Komm, M.; Lemaitre, V.; Nuttens, C.; Pagano, D.; Perrini, L.; Pin, A.; Piotrzkowski, K.; Popov, A.; Quertenmont, L.; Selvaggi, M.; Vidal Marono, M.; Vizan Garcia, J. M.; Beliy, N.; Caebergs, T.; Daubie, E.; Hammad, G. H.; Aldá Júnior, W. L.; Alves, G. A.; Brito, L.; Correa Martins Junior, M.; Dos Reis Martins, T.; Molina, J.; Mora Herrera, C.; Pol, M. E.; Rebello Teles, P.; Carvalho, W.; Chinellato, J.; Custódio, A.; Da Costa, E. M.; De Jesus Damiao, D.; De Oliveira Martins, C.; Fonseca De Souza, S.; Malbouisson, H.; Matos Figueiredo, D.; Mundim, L.; Nogima, H.; Prado Da Silva, W. L.; Santaolalla, J.; Santoro, A.; Sznajder, A.; Tonelli Manganote, E. J.; Vilela Pereira, A.; Bernardes, C. A.; Dogra, S.; Tomei, T. R. Fernandez Perez; Gregores, E. M.; Mercadante, P. G.; Novaes, S. F.; Padula, Sandra S.; Aleksandrov, A.; Genchev, V.; Hadjiiska, R.; Iaydjiev, P.; Marinov, A.; Piperov, S.; Rodozov, M.; Stoykova, S.; Sultanov, G.; Vutova, M.; Dimitrov, A.; Glushkov, I.; Litov, L.; Pavlov, B.; Petkov, P.; Bian, J. G.; Chen, G. M.; Chen, H. S.; Chen, M.; Cheng, T.; Du, R.; Jiang, C. H.; Plestina, R.; Romeo, F.; Tao, J.; Wang, Z.; Asawatangtrakuldee, C.; Ban, Y.; Liu, S.; Mao, Y.; Qian, S. J.; Wang, D.; Xu, Z.; Zhang, F.; Zhang, L.; Zou, W.; Avila, C.; Cabrera, A.; Chaparro Sierra, L. F.; Florez, C.; Gomez, J. P.; Gomez Moreno, B.; Sanabria, J. C.; Godinovic, N.; Lelas, D.; Polic, D.; Puljak, I.; Antunovic, Z.; Kovac, M.; Brigljevic, V.; Kadija, K.; Luetic, J.; Mekterovic, D.; Sudic, L.; Attikis, A.; Mavromanolakis, G.; Mousa, J.; Nicolaou, C.; Ptochos, F.; Razis, P. A.; Rykaczewski, H.; Bodlak, M.; Finger, M.; Finger, M.; Assran, Y.; Ellithi Kamel, A.; Mahmoud, M. A.; Radi, A.; Kadastik, M.; Murumaa, M.; Raidal, M.; Tiko, A.; Eerola, P.; Voutilainen, M.; Härkönen, J.; Karimäki, V.; Kinnunen, R.; Kortelainen, M. J.; Lampén, T.; Lassila-Perini, K.; Lehti, S.; Lindén, T.; Luukka, P.; Mäenpää, T.; Peltola, T.; Tuominen, E.; Tuominiemi, J.; Tuovinen, E.; Wendland, L.; Talvitie, J.; Tuuva, T.; Besancon, M.; Couderc, F.; Dejardin, M.; Denegri, D.; Fabbro, B.; Faure, J. L.; Favaro, C.; Ferri, F.; Ganjour, S.; Givernaud, A.; Gras, P.; Hamel de Monchenault, G.; Jarry, P.; Locci, E.; Malcles, J.; Rander, J.; Rosowsky, A.; Titov, M.; Baffioni, S.; Beaudette, F.; Busson, P.; Chapon, E.; Charlot, C.; Dahms, T.; Dobrzynski, L.; Filipovic, N.; Florent, A.; Granier de Cassagnac, R.; Mastrolorenzo, L.; Miné, P.; Naranjo, I. N.; Nguyen, M.; Ochando, C.; Ortona, G.; Paganini, P.; Regnard, S.; Salerno, R.; Sauvan, J. B.; Sirois, Y.; Veelken, C.; Yilmaz, Y.; Zabi, A.; Agram, J.-L.; Andrea, J.; Aubin, A.; Bloch, D.; Brom, J.-M.; Chabert, E. C.; Collard, C.; Conte, E.; Fontaine, J.-C.; Gelé, D.; Goerlach, U.; Goetzmann, C.; Le Bihan, A.-C.; Skovpen, K.; Van Hove, P.; Gadrat, S.; Beauceron, S.; Beaupere, N.; Bernet, C.; Boudoul, G.; Bouvier, E.; Brochet, S.; Carrillo Montoya, C. A.; Chasserat, J.; Chierici, R.; Contardo, D.; Courbon, B.; Depasse, P.; El Mamouni, H.; Fan, J.; Fay, J.; Gascon, S.; Gouzevitch, M.; Ille, B.; Kurca, T.; Lethuillier, M.; Mirabito, L.; Pequegnot, A. L.; Perries, S.; Ruiz Alvarez, J. D.; Sabes, D.; Sgandurra, L.; Sordini, V.; Vander Donckt, M.; Verdier, P.; Viret, S.; Xiao, H.; Tsamalaidze, Z.; Autermann, C.; Beranek, S.; Bontenackels, M.; Edelhoff, M.; Feld, L.; Heister, A.; Klein, K.; Lipinski, M.; Ostapchuk, A.; Preuten, M.; Raupach, F.; Sammet, J.; Schael, S.; Schulte, J. F.; Weber, H.; Wittmer, B.; Zhukov, V.; Ata, M.; Brodski, M.; Dietz-Laursonn, E.; Duchardt, D.; Erdmann, M.; Fischer, R.; Güth, A.; Hebbeker, T.; Heidemann, C.; Hoepfner, K.; Klingebiel, D.; Knutzen, S.; Kreuzer, P.; Merschmeyer, M.; Meyer, A.; Millet, P.; Olschewski, M.; Padeken, K.; Papacz, P.; Reithler, H.; Schmitz, S. A.; Sonnenschein, L.; Teyssier, D.; Thüer, S.; Cherepanov, V.; Erdogan, Y.; Flügge, G.; Geenen, H.; Geisler, M.; Haj Ahmad, W.; Hoehle, F.; Kargoll, B.; Kress, T.; Kuessel, Y.; Künsken, A.; Lingemann, J.; Nowack, A.; Nugent, I. M.; Pistone, C.; Pooth, O.; Stahl, A.; Aldaya Martin, M.; Asin, I.; Bartosik, N.; Behr, J.; Behrens, U.; Bell, A. J.; Bethani, A.; Borras, K.; Burgmeier, A.; Cakir, A.; Calligaris, L.; Campbell, A.; Choudhury, S.; Costanza, F.; Diez Pardos, C.; Dolinska, G.; Dooling, S.; Dorland, T.; Eckerlin, G.; Eckstein, D.; Eichhorn, T.; Flucke, G.; Garay Garcia, J.; Geiser, A.; Gizhko, A.; Gunnellini, P.; Hauk, J.; Hempel, M.; Jung, H.; Kalogeropoulos, A.; Karacheban, O.; Kasemann, M.; Katsas, P.; Kieseler, J.; Kleinwort, C.; Korol, I.; Krücker, D.; Lange, W.; Leonard, J.; Lipka, K.; Lobanov, A.; Lohmann, W.; Lutz, B.; Mankel, R.; Marfin, I.; Melzer-Pellmann, I.-A.; Meyer, A. B.; Mittag, G.; Mnich, J.; Mussgiller, A.; Naumann-Emme, S.; Nayak, A.; Ntomari, E.; Perrey, H.; Pitzl, D.; Placakyte, R.; Raspereza, A.; Ribeiro Cipriano, P. M.; Roland, B.; Ron, E.; Sahin, M. Ã.-.; Salfeld-Nebgen, J.; Saxena, P.; Schoerner-Sadenius, T.; Schröder, M.; Seitz, C.; Spannagel, S.; Vargas Trevino, A. D. R.; Walsh, R.; Wissing, C.; Blobel, V.; Centis Vignali, M.; Draeger, A. R.; Erfle, J.; Garutti, E.; Goebel, K.; Görner, M.; Haller, J.; Hoffmann, M.; Höing, R. S.; Junkes, A.; Kirschenmann, H.; Klanner, R.; Kogler, R.; Lapsien, T.; Lenz, T.; Marchesini, I.; Marconi, D.; Ott, J.; Peiffer, T.; Perieanu, A.; Pietsch, N.; Poehlsen, J.; Poehlsen, T.; Rathjens, D.; Sander, C.; Schettler, H.; Schleper, P.; Schlieckau, E.; Schmidt, A.; Seidel, M.; Sola, V.; Stadie, H.; Steinbrück, G.; Troendle, D.; Usai, E.; Vanelderen, L.; Vanhoefer, A.; Barth, C.; Baus, C.; Berger, J.; Böser, C.; Butz, E.; Chwalek, T.; De Boer, W.; Descroix, A.; Dierlamm, A.; Feindt, M.; Frensch, F.; Giffels, M.; Gilbert, A.; Hartmann, F.; Hauth, T.; Husemann, U.; Katkov, I.; Kornmayer, A.; Lobelle Pardo, P.; Mozer, M. U.; Müller, T.; Müller, Th.; Nürnberg, A.; Quast, G.; Rabbertz, K.; Röcker, S.; Simonis, H. J.; Stober, F. M.; Ulrich, R.; Wagner-Kuhr, J.; Wayand, S.; Weiler, T.; Wolf, R.; Anagnostou, G.; Daskalakis, G.; Geralis, T.; Giakoumopoulou, V. 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R.; Alexander, J.; Chatterjee, A.; Chaves, J.; Chu, J.; Dittmer, S.; Eggert, N.; Mirman, N.; Nicolas Kaufman, G.; Patterson, J. R.; Ryd, A.; Salvati, E.; Skinnari, L.; Sun, W.; Teo, W. D.; Thom, J.; Thompson, J.; Tucker, J.; Weng, Y.; Winstrom, L.; Wittich, P.; Winn, D.; Abdullin, S.; Albrow, M.; Anderson, J.; Apollinari, G.; Bauerdick, L. A. T.; Beretvas, A.; Berryhill, J.; Bhat, P. C.; Bolla, G.; Burkett, K.; Butler, J. N.; Cheung, H. W. K.; Chlebana, F.; Cihangir, S.; Elvira, V. D.; Fisk, I.; Freeman, J.; Gottschalk, E.; Gray, L.; Green, D.; Grünendahl, S.; Gutsche, O.; Hanlon, J.; Hare, D.; Harris, R. M.; Hirschauer, J.; Hooberman, B.; Jindariani, S.; Johnson, M.; Joshi, U.; Klima, B.; Kreis, B.; Kwan, S.; Linacre, J.; Lincoln, D.; Lipton, R.; Liu, T.; Lopes De Sá, R.; Lykken, J.; Maeshima, K.; Marraffino, J. M.; Martinez Outschoorn, V. I.; Maruyama, S.; Mason, D.; McBride, P.; Merkel, P.; Mishra, K.; Mrenna, S.; Nahn, S.; Newman-Holmes, C.; O'Dell, V.; Prokofyev, O.; Sexton-Kennedy, E.; Soha, A.; Spalding, W. J.; Spiegel, L.; Taylor, L.; Tkaczyk, S.; Tran, N. V.; Uplegger, L.; Vaandering, E. W.; Vidal, R.; Whitbeck, A.; Whitmore, J.; Yang, F.; Acosta, D.; Avery, P.; Bortignon, P.; Bourilkov, D.; Carver, M.; Curry, D.; Das, S.; De Gruttola, M.; Di Giovanni, G. P.; Field, R. D.; Fisher, M.; Furic, I. K.; Hugon, J.; Konigsberg, J.; Korytov, A.; Kypreos, T.; Low, J. F.; Matchev, K.; Mei, H.; Milenovic, P.; Mitselmakher, G.; Muniz, L.; Rinkevicius, A.; Shchutska, L.; Snowball, M.; Sperka, D.; Yelton, J.; Zakaria, M.; Hewamanage, S.; Linn, S.; Markowitz, P.; Martinez, G.; Rodriguez, J. L.; Adams, J. R.; Adams, T.; Askew, A.; Bochenek, J.; Diamond, B.; Haas, J.; Hagopian, S.; Hagopian, V.; Johnson, K. F.; Prosper, H.; Veeraraghavan, V.; Weinberg, M.; Baarmand, M. M.; Hohlmann, M.; Kalakhety, H.; Yumiceva, F.; Adams, M. R.; Apanasevich, L.; Berry, D.; Betts, R. R.; Bucinskaite, I.; Cavanaugh, R.; Evdokimov, O.; Gauthier, L.; Gerber, C. E.; Hofman, D. J.; Kurt, P.; O'Brien, C.; Sandoval Gonzalez, I. D.; Silkworth, C.; Turner, P.; Varelas, N.; Bilki, B.; Clarida, W.; Dilsiz, K.; Haytmyradov, M.; Khristenko, V.; Merlo, J.-P.; Mermerkaya, H.; Mestvirishvili, A.; Moeller, A.; Nachtman, J.; Ogul, H.; Onel, Y.; Ozok, F.; Penzo, A.; Rahmat, R.; Sen, S.; Tan, P.; Tiras, E.; Wetzel, J.; Yi, K.; Anderson, I.; Barnett, B. A.; Blumenfeld, B.; Bolognesi, S.; Fehling, D.; Gritsan, A. V.; Maksimovic, P.; Martin, C.; Swartz, M.; Xiao, M.; Baringer, P.; Bean, A.; Benelli, G.; Bruner, C.; Gray, J.; Kenny, R. P.; Majumder, D.; Malek, M.; Murray, M.; Noonan, D.; Sanders, S.; Sekaric, J.; Stringer, R.; Wang, Q.; Wood, J. S.; Chakaberia, I.; Ivanov, A.; Kaadze, K.; Khalil, S.; Makouski, M.; Maravin, Y.; Saini, L. K.; Skhirtladze, N.; Svintradze, I.; Gronberg, J.; Lange, D.; Rebassoo, F.; Wright, D.; Anelli, C.; Baden, A.; Belloni, A.; Calvert, B.; Eno, S. C.; Gomez, J. A.; Hadley, N. J.; Jabeen, S.; Kellogg, R. G.; Kolberg, T.; Lu, Y.; Mignerey, A. C.; Pedro, K.; Shin, Y. H.; Skuja, A.; Tonjes, M. B.; Tonwar, S. C.; Apyan, A.; Barbieri, R.; Bierwagen, K.; Busza, W.; Cali, I. A.; Di Matteo, L.; Gomez Ceballos, G.; Goncharov, M.; Gulhan, D.; Klute, M.; Lai, Y. S.; Lee, Y.-J.; Levin, A.; Luckey, P. D.; Paus, C.; Ralph, D.; Roland, C.; Roland, G.; Stephans, G. S. F.; Sumorok, K.; Velicanu, D.; Veverka, J.; Wyslouch, B.; Yang, M.; Zanetti, M.; Zhukova, V.; Dahmes, B.; Gude, A.; Kao, S. C.; Klapoetke, K.; Kubota, Y.; Mans, J.; Nourbakhsh, S.; Rusack, R.; Singovsky, A.; Tambe, N.; Turkewitz, J.; Acosta, J. G.; Oliveros, S.; Avdeeva, E.; Bloom, K.; Bose, S.; Claes, D. R.; Dominguez, A.; Gonzalez Suarez, R.; Keller, J.; Knowlton, D.; Kravchenko, I.; Lazo-Flores, J.; Meier, F.; Ratnikov, F.; Snow, G. R.; Zvada, M.; Dolen, J.; Godshalk, A.; Iashvili, I.; Kharchilava, A.; Kumar, A.; Rappoccio, S.; Alverson, G.; Barberis, E.; Baumgartel, D.; Chasco, M.; Massironi, A.; Morse, D. M.; Nash, D.; Orimoto, T.; Trocino, D.; Wang, R.-J.; Wood, D.; Zhang, J.; Hahn, K. A.; Kubik, A.; Mucia, N.; Odell, N.; Pollack, B.; Pozdnyakov, A.; Schmitt, M.; Stoynev, S.; Sung, K.; Trovato, M.; Velasco, M.; Won, S.; Brinkerhoff, A.; Chan, K. M.; Drozdetskiy, A.; Hildreth, M.; Jessop, C.; Karmgard, D. J.; Kellams, N.; Lannon, K.; Lynch, S.; Marinelli, N.; Musienko, Y.; Pearson, T.; Planer, M.; Ruchti, R.; Smith, G.; Valls, N.; Wayne, M.; Wolf, M.; Woodard, A.; Antonelli, L.; Brinson, J.; Bylsma, B.; Durkin, L. S.; Flowers, S.; Hart, A.; Hill, C.; Hughes, R.; Kotov, K.; Ling, T. Y.; Luo, W.; Puigh, D.; Rodenburg, M.; Winer, B. L.; Wolfe, H.; Wulsin, H. W.; Driga, O.; Elmer, P.; Hardenbrook, J.; Hebda, P.; Koay, S. A.; Lujan, P.; Marlow, D.; Medvedeva, T.; Mooney, M.; Olsen, J.; Piroué, P.; Quan, X.; Saka, H.; Stickland, D.; Tully, C.; Werner, J. S.; Zuranski, A.; Brownson, E.; Malik, S.; Mendez, H.; Ramirez Vargas, J. E.; Barnes, V. E.; Benedetti, D.; Bortoletto, D.; Gutay, L.; Hu, Z.; Jha, M. K.; Jones, M.; Jung, K.; Kress, M.; Leonardo, N.; Miller, D. H.; Neumeister, N.; Primavera, F.; Radburn-Smith, B. C.; Shi, X.; Shipsey, I.; Silvers, D.; Svyatkovskiy, A.; Wang, F.; Xie, W.; Xu, L.; Zablocki, J.; Parashar, N.; Stupak, J.; Adair, A.; Akgun, B.; Ecklund, K. M.; Geurts, F. J. M.; Li, W.; Michlin, B.; Padley, B. P.; Redjimi, R.; Roberts, J.; Zabel, J.; Betchart, B.; Bodek, A.; de Barbaro, P.; Demina, R.; Eshaq, Y.; Ferbel, T.; Galanti, M.; Garcia-Bellido, A.; Goldenzweig, P.; Han, J.; Harel, A.; Hindrichs, O.; Khukhunaishvili, A.; Korjenevski, S.; Petrillo, G.; Verzetti, M.; Vishnevskiy, D.; Ciesielski, R.; Demortier, L.; Goulianos, K.; Mesropian, C.; Arora, S.; Barker, A.; Chou, J. P.; Contreras-Campana, C.; Contreras-Campana, E.; Duggan, D.; Ferencek, D.; Gershtein, Y.; Gray, R.; Halkiadakis, E.; Hidas, D.; Hughes, E.; Kaplan, S.; Lath, A.; Panwalkar, S.; Park, M.; Salur, S.; Schnetzer, S.; Sheffield, D.; Somalwar, S.; Stone, R.; Thomas, S.; Thomassen, P.; Walker, M.; Rose, K.; Spanier, S.; York, A.; Bouhali, O.; Castaneda Hernandez, A.; Dalchenko, M.; De Mattia, M.; Dildick, S.; Eusebi, R.; Flanagan, W.; Gilmore, J.; Kamon, T.; Khotilovich, V.; Krutelyov, V.; Montalvo, R.; Osipenkov, I.; Pakhotin, Y.; Patel, R.; Perloff, A.; Roe, J.; Rose, A.; Safonov, A.; Suarez, I.; Tatarinov, A.; Ulmer, K. A.; Akchurin, N.; Cowden, C.; Damgov, J.; Dragoiu, C.; Dudero, P. R.; Faulkner, J.; Kovitanggoon, K.; Kunori, S.; Lee, S. W.; Libeiro, T.; Volobouev, I.; Appelt, E.; Delannoy, A. G.; Greene, S.; Gurrola, A.; Johns, W.; Maguire, C.; Mao, Y.; Melo, A.; Sharma, M.; Sheldon, P.; Snook, B.; Tuo, S.; Velkovska, J.; Arenton, M. W.; Boutle, S.; Cox, B.; Francis, B.; Goodell, J.; Hirosky, R.; Ledovskoy, A.; Li, H.; Lin, C.; Neu, C.; Wolfe, E.; Wood, J.; Clarke, C.; Harr, R.; Karchin, P. E.; Kottachchi Kankanamge Don, C.; Lamichhane, P.; Sturdy, J.; Belknap, D. A.; Carlsmith, D.; Cepeda, M.; Dasu, S.; Dodd, L.; Duric, S.; Friis, E.; Hall-Wilton, R.; Herndon, M.; Hervé, A.; Klabbers, P.; Lanaro, A.; Lazaridis, C.; Levine, A.; Loveless, R.; Mohapatra, A.; Ojalvo, I.; Perry, T.; Pierro, G. A.; Polese, G.; Ross, I.; Sarangi, T.; Savin, A.; Smith, W. H.; Taylor, D.; Vuosalo, C.; Woods, N.; CMS Collaboration

2015-07-01

The second-order azimuthal anisotropy Fourier harmonics, v2 , are obtained in p -Pb and PbPb collisions over a wide pseudorapidity (η ) range based on correlations among six or more charged particles. The p -Pb data, corresponding to an integrated luminosity of 35 nb-1 , were collected during the 2013 LHC p -Pb run at a nucleon-nucleon center-of-mass energy of 5.02 TeV by the CMS experiment. A sample of semiperipheral PbPb collision data at √{sNN }=2.76 TeV , corresponding to an integrated luminosity of 2.5 μ b-1 and covering a similar range of particle multiplicities as the p -Pb data, is also analyzed for comparison. The six- and eight-particle cumulant and the Lee-Yang zeros methods are used to extract the v2 coefficients, extending previous studies of two- and four-particle correlations. For both the p -Pb and PbPb systems, the v2 values obtained with correlations among more than four particles are consistent with previously published four-particle results. These data support the interpretation of a collective origin for the previously observed long-range (large Δ η ) correlations in both systems. The ratios of v2 values corresponding to correlations including different numbers of particles are compared to theoretical predictions that assume a hydrodynamic behavior of a p -Pb system dominated by fluctuations in the positions of participant nucleons. These results provide new insights into the multiparticle dynamics of collision systems with a very small overlapping region.

Environmental Response and Genomic Regions Correlated with Rice Root Growth and Yield under Drought in the OryzaSNP Panel across Multiple Study Systems

PubMed Central

Wade, Len J.; Bartolome, Violeta; Mauleon, Ramil; Vasant, Vivek Deshmuck; Prabakar, Sumeet Mankar; Chelliah, Muthukumar; Kameoka, Emi; Nagendra, K.; Reddy, K. R. Kamalnath; Varma, C. Mohan Kumar; Patil, Kalmeshwar Gouda; Shrestha, Roshi; Al-Shugeairy, Zaniab; Al-Ogaidi, Faez; Munasinghe, Mayuri; Gowda, Veeresh; Semon, Mande; Suralta, Roel R.; Shenoy, Vinay; Vadez, Vincent; Serraj, Rachid; Shashidhar, H. E.; Yamauchi, Akira; Babu, Ranganathan Chandra; Price, Adam; McNally, Kenneth L.; Henry, Amelia

2015-01-01

The rapid progress in rice genotyping must be matched by advances in phenotyping. A better understanding of genetic variation in rice for drought response, root traits, and practical methods for studying them are needed. In this study, the OryzaSNP set (20 diverse genotypes that have been genotyped for SNP markers) was phenotyped in a range of field and container studies to study the diversity of rice root growth and response to drought. Of the root traits measured across more than 20 root experiments, root dry weight showed the most stable genotypic performance across studies. The environment (E) component had the strongest effect on yield and root traits. We identified genomic regions correlated with root dry weight, percent deep roots, maximum root depth, and grain yield based on a correlation analysis with the phenotypes and aus, indica, or japonica introgression regions using the SNP data. Two genomic regions were identified as hot spots in which root traits and grain yield were co-located; on chromosome 1 (39.7–40.7 Mb) and on chromosome 8 (20.3–21.9 Mb). Across experiments, the soil type/ growth medium showed more correlations with plant growth than the container dimensions. Although the correlations among studies and genetic co-location of root traits from a range of study systems points to their potential utility to represent responses in field studies, the best correlations were observed when the two setups had some similar properties. Due to the co-location of the identified genomic regions (from introgression block analysis) with QTL for a number of previously reported root and drought traits, these regions are good candidates for detailed characterization to contribute to understanding rice improvement for response to drought. This study also highlights the utility of characterizing a small set of 20 genotypes for root growth, drought response, and related genomic regions. PMID:25909711

Concurrent validation of Xsens MVN measurement of lower limb joint angular kinematics.

PubMed

Zhang, Jun-Tian; Novak, Alison C; Brouwer, Brenda; Li, Qingguo

2013-08-01

This study aims to validate a commercially available inertial sensor based motion capture system, Xsens MVN BIOMECH using its native protocols, against a camera-based motion capture system for the measurement of joint angular kinematics. Performance was evaluated by comparing waveform similarity using range of motion, mean error and a new formulation of the coefficient of multiple correlation (CMC). Three dimensional joint angles of the lower limbs were determined for ten healthy subjects while they performed three daily activities: level walking, stair ascent, and stair descent. Under all three walking conditions, the Xsens system most accurately determined the flexion/extension joint angle (CMC > 0.96) for all joints. The joint angle measurements associated with the other two joint axes had lower correlation including complex CMC values. The poor correlation in the other two joint axes is most likely due to differences in the anatomical frame definition of limb segments used by the Xsens and Optotrak systems. Implementation of a protocol to align these two systems is necessary when comparing joint angle waveforms measured by the Xsens and other motion capture systems.

Atorvastatin therapy reduces interferon-regulated chemokine CXCL9 plasma levels in patients with systemic lupus erythematosus.

PubMed

Ferreira, G A; Teixeira, A L; Sato, E I

2010-07-01

A recent study showed transcriptional levels of interferon-inducible chemokines in peripheral blood cells were associated with disease activity and organ damage in systemic lupus erythematosus, and may be useful in monitoring disease activity and prognosis. Our objective was to evaluate the capacity of atorvastatin to reduce plasma levels of interferon-regulated chemokines (CCL2, CCL3 and CXCL9) and to study the correlation between these chemokines and disease activity in patients with systemic lupus erythematosus. Eighty-eight female patients with systemic lupus erythematosus were divided into two groups: 64 receiving 20 mg/day of atorvastatin (intervention group) and 24 without atorvastatin (control group). All patients were followed for 8 weeks. At baseline and after 8 weeks laboratory tests were performed for all patients. Plasma levels of chemokines were measured by ELISA using commercial kits (DuoSet, R&D Systems, Minneapolis, USA). In a univariate analysis we found correlation between CCL2, CCL3 and CXCL9 plasma levels and SLEDAI score. In the intervention group we observed a significant decrease in CXCL9 plasma levels comparing baseline and levels at the end of the study (p = 0.04); however, no differences were observed regarding CCL2 or CCL3 plasma levels in this study. No significant difference was observed in the plasma levels of these chemokines in the control group. We conclude that treatment with atorvastatin was associated with a significant decrease in the plasma levels of CXCL9 in patients with systemic lupus erythematosus. As the plasma levels of CXCL9 correlated with the SLEDAI score, we ask whether reducing levels of this chemokine could help to control systemic lupus erythematosus activity.

Neural Correlates of Four Broad Temperament Dimensions: Testing Predictions for a Novel Construct of Personality

PubMed Central

Brown, Lucy L.; Acevedo, Bianca; Fisher, Helen E.

2013-01-01

Four suites of behavioral traits have been associated with four broad neural systems: the 1) dopamine and related norepinephrine system; 2) serotonin; 3) testosterone; 4) and estrogen and oxytocin system. A 56-item questionnaire, the Fisher Temperament Inventory (FTI), was developed to define four temperament dimensions associated with these behavioral traits and neural systems. The questionnaire has been used to suggest romantic partner compatibility. The dimensions were named: Curious/Energetic; Cautious/Social Norm Compliant; Analytical/Tough-minded; and Prosocial/Empathetic. For the present study, the FTI was administered to participants in two functional magnetic resonance imaging studies that elicited feelings of love and attachment, near-universal human experiences. Scores for the Curious/Energetic dimension co-varied with activation in a region of the substantia nigra, consistent with the prediction that this dimension reflects activity in the dopamine system. Scores for the Cautious/Social Norm Compliant dimension correlated with activation in the ventrolateral prefrontal cortex in regions associated with social norm compliance, a trait linked with the serotonin system. Scores on the Analytical/Tough-minded scale co-varied with activity in regions of the occipital and parietal cortices associated with visual acuity and mathematical thinking, traits linked with testosterone. Also, testosterone contributes to brain architecture in these areas. Scores on the Prosocial/Empathetic scale correlated with activity in regions of the inferior frontal gyrus, anterior insula and fusiform gyrus. These are regions associated with mirror neurons or empathy, a trait linked with the estrogen/oxytocin system, and where estrogen contributes to brain architecture. These findings, replicated across two studies, suggest that the FTI measures influences of four broad neural systems, and that these temperament dimensions and neural systems could constitute foundational mechanisms in personality structure and play a role in romantic partnerships. PMID:24236043

Neural correlates of four broad temperament dimensions: testing predictions for a novel construct of personality.

PubMed

Brown, Lucy L; Acevedo, Bianca; Fisher, Helen E

2013-01-01

Four suites of behavioral traits have been associated with four broad neural systems: the 1) dopamine and related norepinephrine system; 2) serotonin; 3) testosterone; 4) and estrogen and oxytocin system. A 56-item questionnaire, the Fisher Temperament Inventory (FTI), was developed to define four temperament dimensions associated with these behavioral traits and neural systems. The questionnaire has been used to suggest romantic partner compatibility. The dimensions were named: Curious/Energetic; Cautious/Social Norm Compliant; Analytical/Tough-minded; and Prosocial/Empathetic. For the present study, the FTI was administered to participants in two functional magnetic resonance imaging studies that elicited feelings of love and attachment, near-universal human experiences. Scores for the Curious/Energetic dimension co-varied with activation in a region of the substantia nigra, consistent with the prediction that this dimension reflects activity in the dopamine system. Scores for the Cautious/Social Norm Compliant dimension correlated with activation in the ventrolateral prefrontal cortex in regions associated with social norm compliance, a trait linked with the serotonin system. Scores on the Analytical/Tough-minded scale co-varied with activity in regions of the occipital and parietal cortices associated with visual acuity and mathematical thinking, traits linked with testosterone. Also, testosterone contributes to brain architecture in these areas. Scores on the Prosocial/Empathetic scale correlated with activity in regions of the inferior frontal gyrus, anterior insula and fusiform gyrus. These are regions associated with mirror neurons or empathy, a trait linked with the estrogen/oxytocin system, and where estrogen contributes to brain architecture. These findings, replicated across two studies, suggest that the FTI measures influences of four broad neural systems, and that these temperament dimensions and neural systems could constitute foundational mechanisms in personality structure and play a role in romantic partnerships.

Impact of variational assimilation using multivariate background error covariances on the simulation of monsoon depressions over India

NASA Astrophysics Data System (ADS)

Dhanya, M.; Chandrasekar, A.

2016-02-01

The background error covariance structure influences a variational data assimilation system immensely. The simulation of a weather phenomenon like monsoon depression can hence be influenced by the background correlation information used in the analysis formulation. The Weather Research and Forecasting Model Data assimilation (WRFDA) system includes an option for formulating multivariate background correlations for its three-dimensional variational (3DVar) system (cv6 option). The impact of using such a formulation in the simulation of three monsoon depressions over India is investigated in this study. Analysis and forecast fields generated using this option are compared with those obtained using the default formulation for regional background error correlations (cv5) in WRFDA and with a base run without any assimilation. The model rainfall forecasts are compared with rainfall observations from the Tropical Rainfall Measurement Mission (TRMM) and the other model forecast fields are compared with a high-resolution analysis as well as with European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-Interim reanalysis. The results of the study indicate that inclusion of additional correlation information in background error statistics has a moderate impact on the vertical profiles of relative humidity, moisture convergence, horizontal divergence and the temperature structure at the depression centre at the analysis time of the cv5/cv6 sensitivity experiments. Moderate improvements are seen in two of the three depressions investigated in this study. An improved thermodynamic and moisture structure at the initial time is expected to provide for improved rainfall simulation. The results of the study indicate that the skill scores of accumulated rainfall are somewhat better for the cv6 option as compared to the cv5 option for at least two of the three depression cases studied, especially at the higher threshold levels. Considering the importance of utilising improved flow-dependent correlation structures for efficient data assimilation, the need for more studies on the impact of background error covariances is obvious.

Study of resonances produced in light nuclei through two and multi particle correlations

NASA Astrophysics Data System (ADS)

Quattrocchi, L.; Acosta, L.; Amorini, F.; Anzalone, A.; Auditore, L.; Berceanu, I.; Cardella, G.; Chbihi, A.; De Filippo, E.; De Luca, S.; Dell' Aquila, D.; Francalanza, L.; Gnoffo, B.; Grzeszczuk, A.; Lanzalone, G.; Lombardo, I.; Martel, I.; Martorana, N. S.; Minniti, T.; Norella, S.; Pagano, A.; Pagano, E. V.; Papa, M.; Pirrone, S.; Politi, G.; Porto, F.; Rizzo, F.; Rosato, E.; Russotto, P.; Trifirò, A.; Trimarchi, M.; Verde, G.; Veselsky, M.; Vigilante, M.

2017-06-01

CORRELATION experiment has been performed at INFN-LNS of Catania, using the 4π multi-detector CHIMERA, with the aim of exploring correlations between two and multi light particle produced in 12C+24Mg collisions at 35 AMeV. Particular attention has been paid to the decay mechanisms of Hoyle state, an excited resonant state of 12C produced via the triple-α process and characterized by a pronounced molecular like structure with three α particles. The study of the Hoyle state is essential for nucleosynthesis, but it also represents a clearly isolated state that can be studied as a three-α cluster system.

Control of the mixing time in vessels agitated by submerged recirculating jets.

PubMed

Kennedy, Stephen; Bhattacharjee, Pradipto K; Bhattacharya, Sati N; Eshtiaghi, Nicky; Parthasarathy, Rajarathinam

2018-01-01

Submerged recirculating jet mixing systems are an efficient and economical method of agitating large tanks with a high hydraulic residence time. Much work has been carried out in developing design correlations to aid the predictions of the mixing time in such systems, with the first such correlation being developed nearly 70 years ago. In most of these correlations, the mixing time depends directly on the volume of the vessel and inversely on the injection velocity of the submerged jet. This work demonstrates, for the first time, that the distance between the injection and suction nozzles also significantly affects the mixing time and can be used to control this time scale. The study introduces a non-dimensional quantity that can be used as an adjustable parameter in systems where such control is desired.

Control of the mixing time in vessels agitated by submerged recirculating jets

PubMed Central

Bhattacharjee, Pradipto K.; Bhattacharya, Sati N.; Eshtiaghi, Nicky; Parthasarathy, Rajarathinam

2018-01-01

Submerged recirculating jet mixing systems are an efficient and economical method of agitating large tanks with a high hydraulic residence time. Much work has been carried out in developing design correlations to aid the predictions of the mixing time in such systems, with the first such correlation being developed nearly 70 years ago. In most of these correlations, the mixing time depends directly on the volume of the vessel and inversely on the injection velocity of the submerged jet. This work demonstrates, for the first time, that the distance between the injection and suction nozzles also significantly affects the mixing time and can be used to control this time scale. The study introduces a non-dimensional quantity that can be used as an adjustable parameter in systems where such control is desired. PMID:29410817

Out-of-time-order correlators in finite open systems

NASA Astrophysics Data System (ADS)

Syzranov, S. V.; Gorshkov, A. V.; Galitski, V.

2018-04-01

We study out-of-time-order correlators (OTOCs) of the form for a quantum system weakly coupled to a dissipative environment. Such an open system may serve as a model of, e.g., a small region in a disordered interacting medium coupled to the rest of this medium considered as an environment. We demonstrate that for a system with discrete energy levels the OTOC saturates exponentially ∝∑aie-t /τi+const to a constant value at t →∞ , in contrast with quantum-chaotic systems which exhibit exponential growth of OTOCs. Focusing on the case of a two-level system, we calculate microscopically the decay times τi and the value of the saturation constant. Because some OTOCs are immune to dephasing processes and some are not, such correlators may decay on two sets of parametrically different time scales related to inelastic transitions between the system levels and to pure dephasing processes, respectively. In the case of a classical environment, the evolution of the OTOC can be mapped onto the evolution of the density matrix of two systems coupled to the same dissipative environment.

Spectroscopic techniques to study the immune response in human saliva

NASA Astrophysics Data System (ADS)

Nepomnyashchaya, E.; Savchenko, E.; Velichko, E.; Bogomaz, T.; Aksenov, E.

2018-01-01

Studies of the immune response dynamics by means of spectroscopic techniques, i.e., laser correlation spectroscopy and fluorescence spectroscopy, are described. The laser correlation spectroscopy is aimed at measuring sizes of particles in biological fluids. The fluorescence spectroscopy allows studying of the conformational and other structural changings in immune complex. We have developed a new scheme of a laser correlation spectrometer and an original signal processing algorithm. We have suggested a new fluorescence detection scheme based on a prism and an integrating pin diode. The developed system based on the spectroscopic techniques allows studies of complex process in human saliva and opens some prospects for an individual treatment of immune diseases.

Statistical Study of Turbulence: Spectral Functions and Correlation Coefficients

NASA Technical Reports Server (NTRS)

Frenkiel, Francois N.

1958-01-01

In reading the publications on turbulence of different authors, one often runs the risk of confusing the various correlation coefficients and turbulence spectra. We have made a point of defining, by appropriate concepts, the differences which exist between these functions. Besides, we introduce in the symbols a few new characteristics of turbulence. In the first chapter, we study some relations between the correlation coefficients and the different turbulence spectra. Certain relations are given by means of demonstrations which could be called intuitive rather than mathematical. In this way we demonstrate that the correlation coefficients between the simultaneous turbulent velocities at two points are identical, whether studied in Lagrange's or in Euler's systems. We then consider new spectra of turbulence, obtained by study of the simultaneous velocities along a straight line of given direction. We determine some relations between these spectra and the correlation coefficients. Examining the relation between the spectrum of the turbulence measured at a fixed point and the longitudinal-correlation curve given by G. I. Taylor, we find that this equation is exact only when the coefficient is very small.

Explore the high-density QCD medium via particle correlations in pPb collisions at CMS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Wei, E-mail: wl33@rice.edu

2015-01-15

The observation of a long-range, near-side two-particle correlation (“ridge”) in very high multiplicity proton–proton and proton–lead collisions has opened up new opportunity of studying novel QCD phenomena in small collision systems. In 2013, high luminosity pPb data were collected by the CMS experiment at the LHC. New results of two- and multi-particle correlations in pPb collisions from CMS are presented over a wide event multiplicity and transverse momentum range. A direct comparison of pPb and PbPb systems is provided. Physics implications, especially in the context of color glass condensate and hydrodynamics models are also discussed.

Two-Photon Fluorescence Correlation Spectroscopy

NASA Technical Reports Server (NTRS)

Zimmerli, Gregory A.; Fischer, David G.

2002-01-01

We will describe a two-photon microscope currently under development at the NASA Glenn Research Center. It is composed of a Coherent Mira 900 tunable, pulsed Titanium:Sapphire laser system, an Olympus Fluoview 300 confocal scanning head, and a Leica DM IRE inverted microscope. It will be used in conjunction with a technique known as fluorescence correlation spectroscopy (FCS) to study intracellular protein dynamics. We will briefly explain the advantages of the two-photon system over a conventional confocal microscope, and provide some preliminary experimental results.

Dynamics of a spin-boson model with structured spectral density

NASA Astrophysics Data System (ADS)

Kurt, Arzu; Eryigit, Resul

2018-05-01

We report the results of a study of the dynamics of a two-state system coupled to an environment with peaked spectral density. An exact analytical expression for the bath correlation function is obtained. Validity range of various approximations to the correlation function for calculating the population difference of the system is discussed as function of tunneling splitting, oscillator frequency, coupling constant, damping rate and the temperature of the bath. An exact expression for the population difference, for a limited range of parameters, is derived.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Omkar, S.; Srikanth, R., E-mail: srik@poornaprajna.org; Banerjee, Subhashish

A protocol based on quantum error correction based characterization of quantum dynamics (QECCD) is developed for quantum process tomography on a two-qubit system interacting dissipatively with a vacuum bath. The method uses a 5-qubit quantum error correcting code that corrects arbitrary errors on the first two qubits, and also saturates the quantum Hamming bound. The dissipative interaction with a vacuum bath allows for both correlated and independent noise on the two-qubit system. We study the dependence of the degree of the correlation of the noise on evolution time and inter-qubit separation.

Stereochemical control factors in the Hantzsch thiazole synthesis: a Hammett substitution correlation analysis.

PubMed

Qiao, Q; So, S S; Goodnow, R A

2001-11-15

[reaction--see text] It is possible to correlate the distribution of stereochemical products produced during a Hantzsch thiazole synthesis according to the Hammett free-energy equation. This analysis confirms the presumed control of the rate of epimerization during thiazole formation due to stabilization of a cationic transition state intermediate during dehydration of the thiazoline ring system. In the chemical system under study, the stereochemical outcome of the reaction also appears to occur according to a kinetically controlled protonation of a thiazoline tautomer.

Network-Based Analysis of Software Change Propagation

PubMed Central

Wang, Rongcun; Qu, Binbin

2014-01-01

The object-oriented software systems frequently evolve to meet new change requirements. Understanding the characteristics of changes aids testers and system designers to improve the quality of softwares. Identifying important modules becomes a key issue in the process of evolution. In this context, a novel network-based approach is proposed to comprehensively investigate change distributions and the correlation between centrality measures and the scope of change propagation. First, software dependency networks are constructed at class level. And then, the number of times of cochanges among classes is minded from software repositories. According to the dependency relationships and the number of times of cochanges among classes, the scope of change propagation is calculated. Using Spearman rank correlation analyzes the correlation between centrality measures and the scope of change propagation. Three case studies on java open source software projects Findbugs, Hibernate, and Spring are conducted to research the characteristics of change propagation. Experimental results show that (i) change distribution is very uneven; (ii) PageRank, Degree, and CIRank are significantly correlated to the scope of change propagation. Particularly, CIRank shows higher correlation coefficient, which suggests it can be a more useful indicator for measuring the scope of change propagation of classes in object-oriented software system. PMID:24790557

Network-based analysis of software change propagation.

PubMed

Wang, Rongcun; Huang, Rubing; Qu, Binbin

2014-01-01

The object-oriented software systems frequently evolve to meet new change requirements. Understanding the characteristics of changes aids testers and system designers to improve the quality of softwares. Identifying important modules becomes a key issue in the process of evolution. In this context, a novel network-based approach is proposed to comprehensively investigate change distributions and the correlation between centrality measures and the scope of change propagation. First, software dependency networks are constructed at class level. And then, the number of times of cochanges among classes is minded from software repositories. According to the dependency relationships and the number of times of cochanges among classes, the scope of change propagation is calculated. Using Spearman rank correlation analyzes the correlation between centrality measures and the scope of change propagation. Three case studies on java open source software projects Findbugs, Hibernate, and Spring are conducted to research the characteristics of change propagation. Experimental results show that (i) change distribution is very uneven; (ii) PageRank, Degree, and CIRank are significantly correlated to the scope of change propagation. Particularly, CIRank shows higher correlation coefficient, which suggests it can be a more useful indicator for measuring the scope of change propagation of classes in object-oriented software system.

[Pulmonary and systemic fat embolism as a cause of death in forensic autopsy practice].

PubMed

Akçay Turan, Arzu; Celik, Safa; Karayel, Ferah; Pakiş, Işil; Arican, Nadir

2006-04-01

The aim of this study was to evaluate the possible correlations between the grade of fat embolism and age, gender, severity of trauma and post-traumatic survival time. Thirty-one cases with pulmonary and/or systemic fat embolism, auotopsied at the Morgue Department of Council of Forensic Medicine were evaluated retrospectively. Twenty-eight cases (90%) died due to trauma and its complications. Nineteen cases (61%) were injured in motor vehicle-related accidents. Post-traumatic survival time varied between 0-384 hours (61.6+/-86.2 hours). Abbreviated injury scale (AIS) was 8.1+/-3.9 and injury severity score (ISS) was 26.5+/-19.7 SD. Twenty-four (77%) cases were determined as isolated pulmonary fat embolism and 7 (23%) cases as systemic fat embolism on histopathological examination. Possible correlations between the grade of fat embolism and age, gender, severity of trauma and post-traumatic survival time were evaluated statistically with using Chi-square and Spearman's correlation tests. There were no correlations between the grade of fat embolism and age, gender, the severity of trauma. Post-traumatic survival time and the severity of trauma had a very weak negative correlation without any statistical significance.

Quantumness and the role of locality on quantum correlations

NASA Astrophysics Data System (ADS)

Bellomo, G.; Plastino, A.; Plastino, A. R.

2016-06-01

Quantum correlations in a physical system are usually studied with respect to a unique and fixed decomposition of the system into subsystems, without fully exploiting the rich structure of the state space. Here, we show several examples in which the consideration of different ways to decompose a physical system enhances the quantum resources and accounts for a more flexible definition of quantumness measures. Furthermore, we give a different perspective regarding how to reassess the fact that local operations play a key role in general quantumness measures that go beyond entanglement—as discordlike ones. We propose a family of measures to quantify the maximum quantumness of a given state. For the discord-based case, we present some analytical results for 2 ×d -dimensional states. Applying our definition to low-dimensional bipartite states, we show that different behaviors can be reported for separable and entangled states vis-à-vis those corresponding to the usual measures of quantum correlations. We show that there is a close link between our proposal and the criterion to witness quantum correlations based on the rank of the correlation matrix, proposed by Dakić, Vedral, and Brukner [Phys. Rev. Lett. 105, 190502 (2010), 10.1103/PhysRevLett.105.190502].

Considerations for multiple hypothesis correlation on tactical platforms

NASA Astrophysics Data System (ADS)

Thomas, Alan M.; Turpen, James E.

2013-05-01

Tactical platforms benefit greatly from the fusion of tracks from multiple sources in terms of increased situation awareness. As a necessary precursor to this track fusion, track-to-track association, or correlation, must first be performed. The related measurement-to-track fusion problem has been well studied with multiple hypothesis tracking and multiple frame assignment methods showing the most success. The track-to-track problem differs from this one in that measurements themselves are not available but rather track state update reports from the measuring sensors. Multiple hypothesis, multiple frame correlation systems have previously been considered; however, their practical implementation under the constraints imposed by tactical platforms is daunting. The situation is further exacerbated by the inconvenient nature of reports from legacy sensor systems on bandwidth- limited communications networks. In this paper, consideration is given to the special difficulties encountered when attempting the correlation of tracks from legacy sensors on tactical aircraft. Those difficulties include the following: covariance information from reporting sensors is frequently absent or incomplete; system latencies can create temporal uncertainty in data; and computational processing is severely limited by hardware and architecture. Moreover, consideration is given to practical solutions for dealing with these problems in a multiple hypothesis correlator.

[The correlations of somatic, dermatoglyphic and psychological characteristics in the structure of general human constitution from the standpoint of systemic approach].

PubMed

Negasheva, M A

2008-01-01

669 young men and women aged 16-23 years were examined using a program including the measurements of 40 body, head and face parameters, fingerprinting and determination of personal psychological characteristics. On the basis of the study of the correlations between the different groups of characteristics, the evidence was obtained that supports the concept of a relative autonomy of the morpho-functional systems as an essential condition for the integrity of the organism as a whole. The coefficients of canonical correlation were calculated between the somatic and dermatoglyphic features (R=0.3), somatic sizes and psychological personality characteristics (R=0.4), psychological characteristics and the dermatoglyphic indices (R=0.4). An original model is suggested that describes the correlations of somatic, dermatoglyphic and psychological features in the structure of general human constitution on the basis of statistically significant canonical correlations (revealed by the author) and that takes in consideration the degree of the influence of genetic and social-economic complex of factors (on the basis of the literature data) on the development and formation of the investigated systems of characteristics.

A study of the relationship between the study process, motivation resources, and motivation problems of nursing students in different educational systems.

PubMed

Yardimci, Figen; Bektaş, Murat; Özkütük, Nilay; Muslu, Gonca Karayağız; Gerçeker, Gülçin Özalp; Başbakkal, Zümrüt

2017-01-01

The study process is related to students' learning approaches and styles. Motivation resources and problems determine students' internal, external, and negative motivation. Analyzing the study process and motivation of students yields important indications about the nature of educational systems in higher education. This study aims to analyze the relationship between the study process, and motivation resources and problems with regard to nursing students in different educational systems in Turkey and to reveal their effects according to a set of variables. This is a descriptive, cross-sectional and correlational study. Traditional, integrated and problem-based learning (PBL) educational programs for nurses involving students from three nursing schools in Turkey. Nursing students (n=330). The data were collected using the Study Process Questionnaire (R-SPQ-2F) and the Motivation Resources and Problems (MRP) Scale. A statistically significant difference was found between the scores on the study process scale, and motivation resources and problems scale among the educational systems. This study determined that the mean scores of students in the PBL system on learning approaches, intrinsic motivation and negative motivation were higher. A positive significant correlation was found between the scales. The study process, and motivation resources and problems were found to be affected by the educational system. This study determined that the PBL educational system more effectively increases students' intrinsic motivation and helps them to acquire learning skills. Copyright © 2016 Elsevier Ltd. All rights reserved.

Comparison of estimates of body fat content in childhood-onset systemic lupus erythematosus.

PubMed

Sinicato, N A; Peres, F A; de Oliveira Peliçari, K; de Oliveira Santos, A; Ramos, C D; Marini, R; Appenzeller, S

2017-04-01

Objective We aimed to compare estimates of body fat content with respect to their ability to predict the percentage of body fat, confirmed by dual-energy X-ray absorptiometry scans in childhood-onset systemic lupus erythematosus. Methods We included 64 consecutive childhood-onset systemic lupus erythematosus patients and 64 healthy age and sex-matched controls in a cross-sectional study. Anthropometric data, body mass index and body adiposity index were calculated for all subjects. Childhood-onset systemic lupus erythematosus patients were further assessed for clinical and laboratory childhood-onset systemic lupus erythematosus manifestations and fat mass, lean mass and percentage of body fat evaluated by dual-energy X-ray absorptiometry. Results Elevated waist/hip ratio was observed in childhood-onset systemic lupus erythematosus patients when compared to controls ( p < 0.001). We did not find differences between body mass index and body adiposity index classification in childhood-onset systemic lupus erythematosus patients and controls. Using dual-energy X-ray absorptiometry as gold standard we observed that all indirect estimates of body fat were correlated with whole body fat mass. We observed a correlation between height and cumulative corticosteroid dose adjusted by weight ( r = 0.429, p = 0.005) in childhood-onset systemic lupus erythematosus. On whole body analysis we observed a correlation between lean mass and ACR Damage Index scores ( r = -0.395; p = 0.019); percentage of body fat and adjusted Systemic Lupus Erythematosus Disease Activity Index ( r = 0.402; p = 0.008), disease duration ( r = -0.370; p = 0.012). On trunk analysis we observed a correlation between lean mass and ACR Damage Index ( r = -0.319; p = 0.042); percentage of body fat with adjusted Systemic Lupus Erythematosus Disease Activity Index ( r = 0.402; p = 0.005), disease duration ( r = -0.408; p = 0.005). Conclusions This is the first study analyzing body adiposity index in childhood-onset systemic lupus erythematosus patients. We observed that all indirect estimates of body fat were correlated with whole body fat mass. This study shows that we should not replace body mass index by body adiposity index to evaluating fat levels in childhood-onset systemic lupus erythematosus. In consideration of the importance of overweight classification in cardiovascular diseases, any direct estimates of body fat can be used in an attempt to improve the prognosis of patients. Note We believe that we have presented evidence of body adiposity index accuracy in childhood-onset systemic lupus erythematosus patients but further research on the generalizability of body adiposity index to other patient groups needs to be done.

A multicenter study analyzing the relationship of a standardized radiographic scoring system of adolescent idiopathic scoliosis and the Scoliosis Research Society outcomes instrument.

PubMed

Wilson, Philip L; Newton, Peter O; Wenger, Dennis R; Haher, Thomas; Merola, Andrew; Lenke, Larry; Lowe, Thomas; Clements, David; Betz, Randy

2002-09-15

A multicenter study examining the association between radiographic and outcomes measures in adolescent idiopathic scoliosis. To evaluate the association between an objective radiographic scoring system and patient quality of life measures as determined by the Scoliosis Research Society outcomes instrument. Although surgical correction of scoliosis has been reported to be positively correlated with patient outcomes, studies to date have been unable to demonstrate an association between radiographic measures of deformity and outcomes measures in patients with adolescent idiopathic scoliosis. A standardized radiographic deformity scoring system and the Scoliosis Research Society outcome tool were used prospectively in seven scoliosis centers to collect data on patients with adolescent idiopathic scoliosis. A total of 354 data points for 265 patients consisting of those with nonoperative or preoperative curves >or=10 degrees, as well as those with surgically treated curves, were analyzed. Correlation analysis was performed to identify significant relationships between any of the radiographic measures, the Harms Study Group radiographic deformity scores (total, sagittal, coronal), and the seven Scoliosis Research Society outcome domains (Total Pain, General Self-Image, General Function, Activity, Postoperative Self-Image, Postoperative Function, and Satisfaction) as well as Scoliosis Research Society outcomes instrument total scores. Radiographic measures that were identified as significantly correlated with Scoliosis Research Society outcome scores were then entered into a stepwise regression analysis. The coronal measures of thoracic curve and lumbar curve magnitude were found to be significantly correlated with the Total Pain, General Self-Image, and total Scoliosis Research Society scores (P < 0.0001). The thoracic and upper thoracic curve magnitudes were also correlated with General Function (P < 0.002). The "coronal" subscore as well as the "total" score of the Harms Study Group radiographic scoring system were also significantly correlated with these Scoliosis Research Society domain and total scores. No radiographic measures taken after surgery were significantly correlated with the postoperative domains of the Scoliosis Research Society outcomes instrument. Stepwise regression analysis of these radiographic measures as predictors of Scoliosis Research Society scores resulted in adjusted R2 values of 0.03-0.07 (P < 0.0001). Although these results show that a significant association exists between the radiographic Cobb angle measure of the scoliosis and the Scoliosis Research Society outcomes scores, the low R2 values indicate that variables other than the radiographic appearance of the deformity (e.g., psychosocial, functional) must also be affecting these scores. The Cobb angle measure of the major deformity has a small, but statistically significant, correlation with the reported Total Pain, General Self-Image, and General Function as measured by the Scoliosis Research Society outcomes instrument. None of the radiographic measures in this population correlated with postoperative domain scores of the Scoliosis Research Society outcomes tool.

Dynamics of correlations in long-range quantum systems follwing a quantum quench

NASA Astrophysics Data System (ADS)

Cevolani, Lorenzo; Carleo, Giuseppe; Sanchez-Palencia, Laurent

We study how and how fast correlations can spread in a quantum system abruptly driven out of equilibrium by a quantum quench. This protocol can be experimentally realized and it allow to address fundamental questions concerning the quasi-locality principle in isolated quantum systems with both short- and long-range interactions. We focus on two different models describing, respectively, lattice bosons, and spins. Our study is based on a combined approach, based on one hand on accurate many-body numerical calculations and on the other hand on a quasi-particle microscopic theory. We find that, for sufficiently fast decaying interaction potential the propagation is ballistic and the Lieb-Robinson bounds for long-range interactions are never attained. When the interactions are really long-range, the scenario is completely different in the two cases. In the bosonic system the locality is preserved and a ballistic propagation is still present while in the spin system an instantaneous propagation of correlations completely destroys locality. Using the microscopic point of view we can quantitatively describe all the different regimes, from instantaneous to ballistic, found in the spin model and we explain how locality is protected in the bosonic model leading to a ballistic propagation. ERC (FP7/2007-2013 No. 256294), QUIC (H2020 No. 641122).

Some Applications of Holography to Study Strongly Correlated Systems

NASA Astrophysics Data System (ADS)

Bhatnagar, Neha

2018-04-01

In this work, we study the transport coefficients of strongly coupled condensed matter systems using gauge/gravity duality (holography). We consider examples from the real world and evaluate the conductivities from their gravity duals. Adopting the bottom-up approach of holography, we obtain the frequency response of the conductivity for (1+1)-dimensional systems. We also evaluate the DC conductivities for non-relativistic condensed matter systems with hyperscaling violating geometry.

Regional variation of nonrural pediatric ambulance transport rates: an ecological study.

PubMed

Maio, R F; Tedeschi, P; Swor, R; Krohmer, J; Ferrel, R; Jacques, D L

1996-08-01

To determine the relationship of pediatric transport rates per hundred thousand pediatric population (RATE) to socioeconomic status (SES) factors and also mortality in Emergency Medical Services (EMS) systems. Retrospective ecological study. Four EMS Medical Control Authorities (MCAs) in Michigan. Patients (3,792), 0-19 years of age, responded to as a nonscheduled emergency response and transported to a hospital by ambulance. RATE, economic status (INCOME), private transportation status (VEHICLE), educational status (EDUC), primary care physician availability (PHYS), and EMS disease death rate (EMSDD) were determined for each MCA and analyzed using Spearman rank correlation. RATE between MCAs varied from 325 to 750. RATE was highest in the most urban MCA: its 0-4 RATE was fourfold larger than any other MCA. INCOME, EDUC, and VEHICLE were inversely correlated with transport rate: -1.00, -1.00, -1.00; P < 0.001. Rate was positively correlated with EMSDD: 1.00; P < 0.001. Substantial variation in RATE between MCAs may be primarily due to the high 0-4 transport rate in the most urban MCA. This study also suggests that higher pediatric EMS system utilization rates may be correlated to higher mortality and also to unavailability of personal transportation.

Performance Analysis of Amplify-and-Forward Systems with Single Relay Selection in Correlated Environments.

PubMed

Van Nguyen, Binh; Kim, Kiseon

2016-09-11

In this paper, we consider amplify-and-forward (AnF) cooperative systems under correlated fading environments. We first present a brief overview of existing works on the effect of channel correlations on the system performance. We then focus on our main contribution which is analyzing the outage probability of a multi-AnF-relay system with the best relay selection (BRS) scheme under a condition that two channels of each relay, source-relay and relay-destination channels, are correlated. Using lower and upper bounds on the end-to-end received signal-to-noise ratio (SNR) at the destination, we derive corresponding upper and lower bounds on the system outage probability. We prove that the system can achieve a diversity order (DO) equal to the number of relays. In addition, and importantly, we show that the considered correlation form has a constructive effect on the system performance. In other words, the larger the correlation coefficient, the better system performance. Our analytic results are corroborated by extensive Monte-Carlo simulations.

Cross-correlation spin noise spectroscopy of heterogeneous interacting spin systems

DOE PAGES

Roy, Dibyendu; Yang, Luyi; Crooker, Scott A.; ...

2015-04-30

Interacting multi-component spin systems are ubiquitous in nature and in the laboratory. As such, investigations of inter-species spin interactions are of vital importance. Traditionally, they are studied by experimental methods that are necessarily perturbative: e.g., by intentionally polarizing or depolarizing one spin species while detecting the response of the other(s). Here, we describe and demonstrate an alternative approach based on multi-probe spin noise spectroscopy, which can reveal inter-species spin interactions - under conditions of strict thermal equilibrium - by detecting and cross-correlating the stochastic fluctuation signals exhibited by each of the constituent spin species. Specifically, we consider a two-component spinmore » ensemble that interacts via exchange coupling, and we determine cross-correlations between their intrinsic spin fluctuations. The model is experimentally confirmed using “two-color” optical spin noise spectroscopy on a mixture of interacting Rb and Cs vapors. Noise correlations directly reveal the presence of inter-species spin exchange, without ever perturbing the system away from thermal equilibrium. These non-invasive and noise-based techniques should be generally applicable to any heterogeneous spin system in which the fluctuations of the constituent components are detectable.« less

Inter-subject Functional Correlation Reveal a Hierarchical Organization of Extrinsic and Intrinsic Systems in the Brain.

PubMed

Ren, Yudan; Nguyen, Vinh Thai; Guo, Lei; Guo, Christine Cong

2017-09-07

The brain is constantly monitoring and integrating both cues from the external world and signals generated intrinsically. These extrinsically and intrinsically-driven neural processes are thought to engage anatomically distinct regions, which are thought to constitute the extrinsic and intrinsic systems of the brain. While the specialization of extrinsic and intrinsic system is evident in primary and secondary sensory cortices, a systematic mapping of the whole brain remains elusive. Here, we characterized the extrinsic and intrinsic functional activities in the brain during naturalistic movie-viewing. Using a novel inter-subject functional correlation (ISFC) analysis, we found that the strength of ISFC shifts along the hierarchical organization of the brain. Primary sensory cortices appear to have strong inter-subject functional correlation, consistent with their role in processing exogenous information, while heteromodal regions that attend to endogenous processes have low inter-subject functional correlation. Those brain systems with higher intrinsic tendency show greater inter-individual variability, likely reflecting the aspects of brain connectivity architecture unique to individuals. Our study presents a novel framework for dissecting extrinsically- and intrinsically-driven processes, as well as examining individual differences in brain function during naturalistic stimulation.

Lack of Correlation Between Pulmonary and Systemic Inflammation Markers in Patients with Chronic Obstructive Pulmonary Disease: A Simultaneous, Two-Compartmental Analysis.

PubMed

Núñez, Belen; Sauleda, Jaume; Garcia-Aymerich, Judith; Noguera, Aina; Monsó, Eduard; Gómez, Federico; Barreiro, Esther; Marín, Alicia; Antó, Josep Maria; Agusti, Alvar

2016-07-01

The origin of systemic inflammation in chronic obstructive pulmonary disease (COPD) patients remains to be defined, but one of the most widely accepted hypothesis is the 'spill over' of inflammatory mediators from the lung to the circulation. To evaluate the relationship between pulmonary and systemic inflammation in COPD quantifying several inflammatory markers in sputum and serum determined simultaneously. Correlations between various inflammatory variables (TNF-α, IL6, IL8) in sputum and serum were evaluated in 133 patients from the PAC-COPD cohort study. A secondary objective was the evaluation of relationships between inflammatory variables and lung function. Inflammatory markers were clearly higher in sputum than in serum. No significant correlation was found (absolute value, r=0.03-0.24) between inflammatory markers in blood and in sputum. There were no significant associations identified between those markers and lung function variables, such as FEV1, DLCO and PaO2 neither. We found no correlation between pulmonary and systemic inflammation in patients with stable COPD, suggesting different pathogenic mechanisms. Copyright © 2016 SEPAR. Published by Elsevier Espana. All rights reserved.

Surface and finite size effect on fluctuations dynamics in nanoparticles with long-range order

NASA Astrophysics Data System (ADS)

Morozovska, A. N.; Eliseev, E. A.

2010-02-01

The influence of surface and finite size on the dynamics of the order parameter fluctuations and critical phenomena in the three-dimensional (3D)-confined systems with long-range order was not considered theoretically. In this paper, we study the influence of surface and finite size on the dynamics of the order parameter fluctuations in the particles of arbitrary shape. We consider concrete examples of the spherical and cylindrical ferroic nanoparticles within Landau-Ginzburg-Devonshire phenomenological approach. Allowing for the strong surface energy contribution in micro and nanoparticles, the analytical expressions derived for the Ornstein-Zernike correlator of the long-range order parameter spatial-temporal fluctuations, dynamic generalized susceptibility, relaxation times, and correlation radii discrete spectra are different from those known for bulk systems. Obtained analytical expressions for the correlation function of the order parameter spatial-temporal fluctuations in micro and nanosized systems can be useful for the quantitative analysis of the dynamical structural factors determined from magnetic resonance diffraction and scattering spectra. Besides the practical importance of the correlation function for the analysis of the experimental data, derived expressions for the fluctuations strength determine the fundamental limits of phenomenological theories applicability for 3D-confined systems.

Direct reconstruction of the two-dimensional pair distribution function in partially ordered systems with angular correlations.

PubMed

Zaluzhnyy, I A; Kurta, R P; Menushenkov, A P; Ostrovskii, B I; Vartanyants, I A

2016-09-01

An x-ray scattering approach to determine the two-dimensional (2D) pair distribution function (PDF) in partially ordered 2D systems is proposed. We derive relations between the structure factor and PDF that enable quantitative studies of positional and bond-orientational (BO) order in real space. We apply this approach in the x-ray study of a liquid crystal (LC) film undergoing the smectic-A-hexatic-B phase transition, to analyze the interplay between the positional and BO order during the temperature evolution of the LC film. We analyze the positional correlation length in different directions in real space.

Comparing quantitative values of two generations of laser-assisted indocyanine green dye angiography systems: can we predict necrosis?

PubMed

Phillips, Brett T; Fourman, Mitchell S; Rivara, Andrew; Dagum, Alexander B; Huston, Tara L; Ganz, Jason C; Bui, Duc T; Khan, Sami U

2014-01-01

Several devices exist today to assist the intraoperative determination of skin flap perfusion. Laser-Assisted Indocyanine Green Dye Angiography (LAICGA) has been shown to accurately predict mastectomy skin flap necrosis using quantitative perfusion values. The laser properties of the latest LAICGA device (SPY Elite) differ significantly from its predecessor system (SPY 2001), preventing direct translation of previous published data. The purpose of this study was to establish a mathematical relationship of perfusion values between these 2 devices. Breast reconstruction patients were prospectively enrolled into a clinical trial where skin flap evaluation and excision was based on quantitative SPY Q values previously established in the literature. Initial study patients underwent mastectomy skin flap evaluation using both SPY systems simultaneously. Absolute perfusion unit (APU) values at identical locations on the breast were then compared graphically. 210 data points were identified on the same patients (n = 4) using both SPY systems. A linear relationship (y = 2.9883x + 12.726) was identified with a high level or correlation (R(2) = 0.744). Previously published values using SPY 2001 (APU 3.7) provided a value of 23.8 APU on the SPY Elite. In addition, postoperative necrosis in these patients correlated to regions of skin identified with the SPY Elite with APU less than 23.8. Intraoperative comparison of LAICGA systems has provided direct correlation of perfusion values predictive of necrosis that were previously established in the literature. An APU value of 3.7 from the SPY 2001 correlates to a SPY Elite APU value of 23.8.

Comparing Quantitative Values of Two Generations of Laser-Assisted Indocyanine Green Dye Angiography Systems: Can We Predict Necrosis?

PubMed Central

Fourman, Mitchell S.; Rivara, Andrew; Dagum, Alexander B.; Huston, Tara L.; Ganz, Jason C.; Bui, Duc T.; Khan, Sami U.

2014-01-01

Objective: Several devices exist today to assist the intraoperative determination of skin flap perfusion. Laser-Assisted Indocyanine Green Dye Angiography (LAICGA) has been shown to accurately predict mastectomy skin flap necrosis using quantitative perfusion values. The laser properties of the latest LAICGA device (SPY Elite) differ significantly from its predecessor system (SPY 2001), preventing direct translation of previous published data. The purpose of this study was to establish a mathematical relationship of perfusion values between these 2 devices. Methods: Breast reconstruction patients were prospectively enrolled into a clinical trial where skin flap evaluation and excision was based on quantitative SPY Q values previously established in the literature. Initial study patients underwent mastectomy skin flap evaluation using both SPY systems simultaneously. Absolute perfusion unit (APU) values at identical locations on the breast were then compared graphically. Results: 210 data points were identified on the same patients (n = 4) using both SPY systems. A linear relationship (y = 2.9883x + 12.726) was identified with a high level or correlation (R2 = 0.744). Previously published values using SPY 2001 (APU 3.7) provided a value of 23.8 APU on the SPY Elite. In addition, postoperative necrosis in these patients correlated to regions of skin identified with the SPY Elite with APU less than 23.8. Conclusion: Intraoperative comparison of LAICGA systems has provided direct correlation of perfusion values predictive of necrosis that were previously established in the literature. An APU value of 3.7 from the SPY 2001 correlates to a SPY Elite APU value of 23.8. PMID:25525483

Adequacy assessment of composite generation and transmission systems incorporating wind energy conversion systems

NASA Astrophysics Data System (ADS)

Gao, Yi

The development and utilization of wind energy for satisfying electrical demand has received considerable attention in recent years due to its tremendous environmental, social and economic benefits, together with public support and government incentives. Electric power generation from wind energy behaves quite differently from that of conventional sources. The fundamentally different operating characteristics of wind energy facilities therefore affect power system reliability in a different manner than those of conventional systems. The reliability impact of such a highly variable energy source is an important aspect that must be assessed when the wind power penetration is significant. The focus of the research described in this thesis is on the utilization of state sampling Monte Carlo simulation in wind integrated bulk electric system reliability analysis and the application of these concepts in system planning and decision making. Load forecast uncertainty is an important factor in long range planning and system development. This thesis describes two approximate approaches developed to reduce the number of steps in a load duration curve which includes load forecast uncertainty, and to provide reasonably accurate generating and bulk system reliability index predictions. The developed approaches are illustrated by application to two composite test systems. A method of generating correlated random numbers with uniform distributions and a specified correlation coefficient in the state sampling method is proposed and used to conduct adequacy assessment in generating systems and in bulk electric systems containing correlated wind farms in this thesis. The studies described show that it is possible to use the state sampling Monte Carlo simulation technique to quantitatively assess the reliability implications associated with adding wind power to a composite generation and transmission system including the effects of multiple correlated wind sites. This is an important development as it permits correlated wind farms to be incorporated in large practical system studies without requiring excessive increases in computer solution time. The procedures described in this thesis for creating monthly and seasonal wind farm models should prove useful in situations where time period models are required to incorporate scheduled maintenance of generation and transmission facilities. There is growing interest in combining deterministic considerations with probabilistic assessment in order to evaluate the quantitative system risk and conduct bulk power system planning. A relatively new approach that incorporates deterministic and probabilistic considerations in a single risk assessment framework has been designated as the joint deterministic-probabilistic approach. The research work described in this thesis illustrates that the joint deterministic-probabilistic approach can be effectively used to integrate wind power in bulk electric system planning. The studies described in this thesis show that the application of the joint deterministic-probabilistic method provides more stringent results for a system with wind power than the traditional deterministic N-1 method because the joint deterministic-probabilistic technique is driven by the deterministic N-1 criterion with an added probabilistic perspective which recognizes the power output characteristics of a wind turbine generator.

Dynamics of cancerous tissue correlates with invasiveness

NASA Astrophysics Data System (ADS)

West, Ann-Katrine Vransø; Wullkopf, Lena; Christensen, Amalie; Leijnse, Natascha; Tarp, Jens Magelund; Mathiesen, Joachim; Erler, Janine Terra; Oddershede, Lene Broeng

2017-03-01

Two of the classical hallmarks of cancer are uncontrolled cell division and tissue invasion, which turn the disease into a systemic, life-threatening condition. Although both processes are studied, a clear correlation between cell division and motility of cancer cells has not been described previously. Here, we experimentally characterize the dynamics of invasive and non-invasive breast cancer tissues using human and murine model systems. The intrinsic tissue velocities, as well as the divergence and vorticity around a dividing cell correlate strongly with the invasive potential of the tissue, thus showing a distinct correlation between tissue dynamics and aggressiveness. We formulate a model which treats the tissue as a visco-elastic continuum. This model provides a valid reproduction of the cancerous tissue dynamics, thus, biological signaling is not needed to explain the observed tissue dynamics. The model returns the characteristic force exerted by an invading cell and reveals a strong correlation between force and invasiveness of breast cancer cells, thus pinpointing the importance of mechanics for cancer invasion.

Hierarchy in directed random networks.

PubMed

Mones, Enys

2013-02-01

In recent years, the theory and application of complex networks have been quickly developing in a markable way due to the increasing amount of data from real systems and the fruitful application of powerful methods used in statistical physics. Many important characteristics of social or biological systems can be described by the study of their underlying structure of interactions. Hierarchy is one of these features that can be formulated in the language of networks. In this paper we present some (qualitative) analytic results on the hierarchical properties of random network models with zero correlations and also investigate, mainly numerically, the effects of different types of correlations. The behavior of the hierarchy is different in the absence and the presence of giant components. We show that the hierarchical structure can be drastically different if there are one-point correlations in the network. We also show numerical results suggesting that the hierarchy does not change monotonically with the correlations and there is an optimal level of nonzero correlations maximizing the level of hierarchy.

Robustness of Oscillatory Behavior in Correlated Networks

PubMed Central

Sasai, Takeyuki; Morino, Kai; Tanaka, Gouhei; Almendral, Juan A.; Aihara, Kazuyuki

2015-01-01

Understanding network robustness against failures of network units is useful for preventing large-scale breakdowns and damages in real-world networked systems. The tolerance of networked systems whose functions are maintained by collective dynamical behavior of the network units has recently been analyzed in the framework called dynamical robustness of complex networks. The effect of network structure on the dynamical robustness has been examined with various types of network topology, but the role of network assortativity, or degree–degree correlations, is still unclear. Here we study the dynamical robustness of correlated (assortative and disassortative) networks consisting of diffusively coupled oscillators. Numerical analyses for the correlated networks with Poisson and power-law degree distributions show that network assortativity enhances the dynamical robustness of the oscillator networks but the impact of network disassortativity depends on the detailed network connectivity. Furthermore, we theoretically analyze the dynamical robustness of correlated bimodal networks with two-peak degree distributions and show the positive impact of the network assortativity. PMID:25894574

Demonstration of correlative atomic force and transmission electron microscopy using actin cytoskeleton

PubMed Central

Yamada, Yutaro; Konno, Hiroki; Shimabukuro, Katsuya

2017-01-01

In this study, we present a new technique called correlative atomic force and transmission electron microscopy (correlative AFM/TEM) in which a targeted region of a sample can be observed under AFM and TEM. The ultimate goal of developing this new technique is to provide a technical platform to expand the fields of AFM application to complex biological systems such as cell extracts. Recent advances in the time resolution of AFM have enabled detailed observation of the dynamic nature of biomolecules. However, specifying molecular species, by AFM alone, remains a challenge. Here, we demonstrate correlative AFM/TEM, using actin filaments as a test sample, and further show that immuno-electron microscopy (immuno-EM), to specify molecules, can be integrated into this technique. Therefore, it is now possible to specify molecules, captured under AFM, by subsequent observation using immuno-EM. In conclusion, correlative AFM/TEM can be a versatile method to investigate complex biological systems at the molecular level. PMID:28828286

Evaluation of several ultrasonography scoring systems for synovitis and comparison to clinical examination: results from a prospective multicentre study of rheumatoid arthritis.

PubMed

Dougados, Maxime; Jousse-Joulin, Sandrine; Mistretta, Frederic; d'Agostino, Maria-Antonietta; Backhaus, Marina; Bentin, Jacques; Chalès, Gérard; Chary-Valckenaere, Isabelle; Conaghan, Philip; Etchepare, Fabien; Gaudin, Philippe; Grassi, Walter; van der Heijde, Désirée; Sellam, Jérémie; Naredo, Esperanza; Szkudlarek, Marcin; Wakefield, Richard; Saraux, Alain

2010-05-01

To evaluate different global ultrasonographic (US) synovitis scoring systems as potential outcome measures of rheumatoid arthritis (RA) according to the Outcome Measures in Rheumatoid Arthritis Clinical Trials (OMERACT) filter. To study selected global scoring systems, for the clinical, B mode and power Doppler techniques, the following joints were evaluated: 28 joints (28-joint Disease Activity Score (DAS28)), 20 joints (metacarpophalangeals (MCPs) + metatarsophalangeals (MTPs)) and 38 joints (28 joints + MTPs) using either a binary (yes/no) or a 0-3 grade. The study was a prospective, 4-month duration follow-up of 76 patients with RA requiring anti-tumour necrosis factor (TNF) therapy (complete follow-up data: 66 patients). Intraobserver reliability was evaluated using the intraclass correlation coefficient (ICC), construct validity was evaluated using the Cronbach alpha test and external validity was evaluated using level of correlation between scoring system and C reactive protein (CRP). Sensitivity to change was evaluated using the standardised response mean. Discriminating capacity was evaluated using the standardised mean differences in patients considered by the doctor as significantly improved or not at the end of the study. Different clinimetric properties of various US scoring systems were at least as good as the clinical scores with, for example, intraobserver reliability ranging from 0.61 to 0.97 versus from 0.53 to 0.82, construct validity ranging from 0.76 to 0.89 versus from 0.76 to 0.88, correlation with CRP ranging from 0.28 to 0.34 versus from 0.28 to 0.35 and sensitivity to change ranging from 0.60 to 1.21 versus from 0.96 to 1.36 for US versus clinical scoring systems, respectively. This study suggests that US evaluation of synovitis is an outcome measure at least as relevant as physical examination. Further studies are required in order to achieve optimal US scoring systems for monitoring patients with RA in clinical trials and in clinical practice.

Estimating historical groundwater levels based on relations with hydrologic and meteorological variables in the U.S. glacial aquifer system

NASA Astrophysics Data System (ADS)

Dudley, R. W.; Hodgkins, G. A.; Nielsen, M. G.; Qi, S. L.

2018-07-01

A number of previous studies have examined relations between groundwater levels and hydrologic and meteorological variables over parts of the glacial aquifer system, but systematic analyses across the entire U.S. glacial aquifer system are lacking. We tested correlations between monthly groundwater levels measured at 1043 wells in the U.S. glacial aquifer system considered to be minimally influenced by human disturbance and selected hydrologic and meteorological variables with the goal of extending historical groundwater records where there were strong correlations. Groundwater levels in the East region correlated most strongly with short-term (1 and 3 month) averages of hydrologic and meteorological variables, while those in the Central and West Central regions yielded stronger correlations with hydrologic and meteorological variables averaged over longer time intervals (6-12 months). Variables strongly correlated with high and low annual groundwater levels were identified as candidate records for use in statistical linear models as a means to fill in and extend historical high and low groundwater levels respectively. Overall, 37.4% of study wells meeting data criteria had successful models for high and (or) low groundwater levels; these wells shared characteristics of relatively higher local precipitation, higher local land-surface slope, lower amounts of clay within the surficial sediments, and higher base-flow index. Streamflow and base flow served as explanatory variables in about two thirds of both high- and low-groundwater-level models in all three regions, and generally yielded more and better models compared to precipitation and Palmer Drought Severity Index. The use of variables such as streamflow with substantially longer and more complete records than those of groundwater wells provide a means for placing contemporary groundwater levels in a longer historical context and can support site-specific analyses such as groundwater modeling.

Modeling Aquatic Toxicity through Chromatographic Systems.

PubMed

Fernández-Pumarega, Alejandro; Amézqueta, Susana; Farré, Sandra; Muñoz-Pascual, Laura; Abraham, Michael H; Fuguet, Elisabet; Rosés, Martí

2017-08-01

Environmental risk assessment requires information about the toxicity of the growing number of chemical products coming from different origins that can contaminate water and become toxicants to aquatic species or other living beings via the trophic chain. Direct toxicity measurements using sensitive aquatic species can be carried out but they may become expensive and ethically questionable. Literature refers to the use of chromatographic measurements that correlate to the toxic effect of a compound over a specific aquatic species as an alternative to get toxicity information. In this work, we have studied the similarity in the response of the toxicity to different species and we have selected eight representative aquatic species (including tadpoles, fish, water fleas, protozoan, and bacteria) with known nonspecific toxicity to chemical substances. Next, we have selected four chromatographic systems offering good perspectives for surrogation of the eight selected aquatic systems, and thus prediction of toxicity from the chromatographic measurement. Then toxicity has been correlated to the chromatographic retention factor. Satisfactory correlation results have been obtained to emulate toxicity in five of the selected aquatic species through some of the chromatographic systems. Other aquatic species with similar characteristics to these five representative ones could also be emulated by using the same chromatographic systems. The final aim of this study is to model chemical products toxicity to aquatic species by means of chromatographic systems to reduce in vivo testing.

Feasibility study of a layer-oriented wavefront sensor for solar telescopes.

PubMed

Marino, Jose; Wöger, Friedrich

2014-02-01

Solar multiconjugate adaptive optics systems rely on several wavefront sensors, which measure the incoming turbulent phase along several field directions to produce a tomographic reconstruction of the turbulent phase. In this paper, we explore an alternative wavefront sensing approach that attempts to directly measure the turbulent phase present at a particular height in the atmosphere: a layer-oriented cross-correlating Shack-Hartmann wavefront sensor (SHWFS). In an experiment at the Dunn Solar Telescope, we built a prototype layer-oriented cross-correlating SHWFS system conjugated to two separate atmospheric heights. We present the data obtained in the observations and complement these with ray-tracing computations to achieve a better understanding of the instrument's performance and limitations. The results obtained in this study strongly indicate that a layer-oriented cross-correlating SHWFS is not a practical design to measure the wavefront at a high layer in the atmosphere.

Empirical Validation of a New Category System: One Example.

ERIC Educational Resources Information Center

Rosenshine, Barak; And Others

This study found that data from previous research can be used to validate a new observational category system and that subscripting of the original ten categories of the Flanders Interaction Analysis System is useful in identifying more specific behaviors which correlate with student achievement. The new category system was the Expanded…

The study of human venous system dynamics using hybrid computer modeling

NASA Technical Reports Server (NTRS)

Snyder, M. F.; Rideout, V. C.

1972-01-01

A computer-based model of the cardiovascular system was created emphasizing effects on the systemic venous system. Certain physiological aspects were emphasized: effects of heart rate, tilting, changes in respiration, and leg muscular contractions. The results from the model showed close correlation with findings previously reported in the literature.

Systemic mastocytosis: CT and US features of abdominal manifestations.

PubMed

Avila, N A; Ling, A; Worobec, A S; Mican, J M; Metcalfe, D D

1997-02-01

To study the imaging findings in patients with systemic mastocytosis and to correlate the findings with the severity of disease on the basis of an established classification system. Pathologic findings, when available, were correlated with imaging findings. Computed tomographic (CT) and ultrasound (US) scans and corresponding pathologic findings, when available, were retrospectively reviewed in 27 patients with systemic mastocytosis. Only five (19%) of the patients in our series had normal abdominal CT and/or US examination results. Common abdominal imaging findings associated with systemic mastocytosis were hepatosplenomegaly, retroperitoneal adenopathy, periportal adenopathy, mesenteric adenopathy, thickening of the omentum and the mesentery, and ascites. Less common findings included hepatofugal portal venous flow, Budd-Chiari syndrome, cavernous transformation of the portal vein, ovarian mass, and complications such as chloroma. The findings were more common in patients with category II and those with category III disease. Abdominal findings at CT and US are common in patients with systemic mastocytosis. Although the findings in patients with systemic mastocytosis are not specific to the disease, they are useful in directing further studies for diagnostic confirmation and in estimating the extent of systemic involvement.

Individual differences in non-symbolic numerical abilities predict mathematical achievements but contradict ATOM.

PubMed

Agrillo, Christian; Piffer, Laura; Adriano, Andrea

2013-07-01

A significant debate surrounds the nature of the cognitive mechanisms involved in non-symbolic number estimation. Several studies have suggested the existence of the same cognitive system for estimation of time, space, and number, called "a theory of magnitude" (ATOM). In addition, researchers have proposed the theory that non-symbolic number abilities might support our mathematical skills. Despite the large number of studies carried out, no firm conclusions can be drawn on either topic. In the present study, we correlated the performance of adults on non-symbolic magnitude estimations and symbolic numerical tasks. Non-symbolic magnitude abilities were assessed by asking participants to estimate which auditory tone lasted longer (time), which line was longer (space), and which group of dots was more numerous (number). To assess symbolic numerical abilities, participants were required to perform mental calculations and mathematical reasoning. We found a positive correlation between non-symbolic and symbolic numerical abilities. On the other hand, no correlation was found among non-symbolic estimations of time, space, and number. Our study supports the idea that mathematical abilities rely on rudimentary numerical skills that predate verbal language. By contrast, the lack of correlation among non-symbolic estimations of time, space, and number is incompatible with the idea that these magnitudes are entirely processed by the same cognitive system.

Research of diagnosis sensors fault based on correlation analysis of the bridge structural health monitoring system

NASA Astrophysics Data System (ADS)

Hu, Shunren; Chen, Weimin; Liu, Lin; Gao, Xiaoxia

2010-03-01

Bridge structural health monitoring system is a typical multi-sensor measurement system due to the multi-parameters of bridge structure collected from the monitoring sites on the river-spanning bridges. Bridge structure monitored by multi-sensors is an entity, when subjected to external action; there will be different performances to different bridge structure parameters. Therefore, the data acquired by each sensor should exist countless correlation relation. However, complexity of the correlation relation is decided by complexity of bridge structure. Traditionally correlation analysis among monitoring sites is mainly considered from physical locations. unfortunately, this method is so simple that it cannot describe the correlation in detail. The paper analyzes the correlation among the bridge monitoring sites according to the bridge structural data, defines the correlation of bridge monitoring sites and describes its several forms, then integrating the correlative theory of data mining and signal system to establish the correlation model to describe the correlation among the bridge monitoring sites quantificationally. Finally, The Chongqing Mashangxi Yangtze river bridge health measurement system is regards as research object to diagnosis sensors fault, and simulation results verify the effectiveness of the designed method and theoretical discussions.

Effective homogeneity of the exchange-correlation and non-interacting kinetic energy functionals under density scaling.

PubMed

Borgoo, Alex; Teale, Andrew M; Tozer, David J

2012-01-21

Correlated electron densities, experimental ionisation potentials, and experimental electron affinities are used to investigate the homogeneity of the exchange-correlation and non-interacting kinetic energy functionals of Kohn-Sham density functional theory under density scaling. Results are presented for atoms and small molecules, paying attention to the influence of the integer discontinuity and the choice of the electron affinity. For the exchange-correlation functional, effective homogeneities are highly system-dependent on either side of the integer discontinuity. By contrast, the average homogeneity-associated with the potential that averages over the discontinuity-is generally close to 4/3 when the discontinuity is computed using positive affinities for systems that do bind an excess electron and negative affinities for those that do not. The proximity to 4/3 becomes increasingly pronounced with increasing atomic number. Evaluating the discontinuity using a zero affinity in systems that do not bind an excess electron instead leads to effective homogeneities on the electron abundant side that are close to 4/3. For the non-interacting kinetic energy functional, the effective homogeneities are less system-dependent and the effect of the integer discontinuity is less pronounced. Average values are uniformly below 5/3. The study provides information that may aid the development of improved exchange-correlation and non-interacting kinetic energy functionals. © 2012 American Institute of Physics

Increased expression of low density granulocytes in juvenile-onset systemic lupus erythematosus patients correlates with disease activity.

PubMed

Midgley, A; Beresford, M W

2016-04-01

Neutrophils are implicated in a wide range of non-infectious inflammatory conditions. A subset of neutrophils in the peripheral circulation of systemic lupus erythematosus (SLE) patients has been described and termed low density granulocytes (LDGs). This study investigates the expression of LDG in juvenile-onset SLE (JSLE) patients compared to controls, and any correlations with disease activity.Neutrophils and LDGs were isolated from JSLE (n = 13) and paediatric non-inflammatory control patients (n = 12). Cell populations were assessed and compared using flow cytometry and morphological analysis. Standard clinical data, which included disease activity markers/scores, were collected for each patient.Significantly increased LDG expression (%mean ± SEM, range) was observed in JSLE patients (10.4 ± 3.26, 3.41-36.3) compared to controls (2.4 ± 0.44, 0.36-5.27; p = 0.005). A statistically significant positive correlation was observed between LDG expression and the British Isles Lupus Activity Group (correlation coefficient 0.685; p = 0.010) and SLE Disease Activity Index (correlation coefficient 0.567; p = 0.043) and the biomarker of dsDNA-antibodies (correlation coefficient 0.590; p = 0.043).Here we observe increased expression in LDGs in JSLE patients, which correlate with dsDNA antibody concentration and scores of disease activity. These correlations indicate that the increased LDG expression observed in this study may have a potential role in the pathogenesis of JSLE, and may be a useful biomarker. © The Author(s) 2015.

Statistical mechanics of the cluster Ising model

NASA Astrophysics Data System (ADS)

Smacchia, Pietro; Amico, Luigi; Facchi, Paolo; Fazio, Rosario; Florio, Giuseppe; Pascazio, Saverio; Vedral, Vlatko

2011-08-01

We study a Hamiltonian system describing a three-spin-1/2 clusterlike interaction competing with an Ising-like antiferromagnetic interaction. We compute free energy, spin-correlation functions, and entanglement both in the ground and in thermal states. The model undergoes a quantum phase transition between an Ising phase with a nonvanishing magnetization and a cluster phase characterized by a string order. Any two-spin entanglement is found to vanish in both quantum phases because of a nontrivial correlation pattern. Nevertheless, the residual multipartite entanglement is maximal in the cluster phase and dependent on the magnetization in the Ising phase. We study the block entropy at the critical point and calculate the central charge of the system, showing that the criticality of the system is beyond the Ising universality class.

A chemical risk ranking and scoring method for the selection of harmful substances to be specially controlled in occupational environments.

PubMed

Shin, Saemi; Moon, Hyung-Il; Lee, Kwon Seob; Hong, Mun Ki; Byeon, Sang-Hoon

2014-11-20

This study aimed to devise a method for prioritizing hazardous chemicals for further regulatory action. To accomplish this objective, we chose appropriate indicators and algorithms. Nine indicators from the Globally Harmonized System of Classification and Labeling of Chemicals were used to identify categories to which the authors assigned numerical scores. Exposure indicators included handling volume, distribution, and exposure level. To test the method devised by this study, sixty-two harmful substances controlled by the Occupational Safety and Health Act in Korea, including acrylamide, acrylonitrile, and styrene were ranked using this proposed method. The correlation coefficients between total score and each indicator ranged from 0.160 to 0.641, and those between total score and hazard indicators ranged from 0.603 to 0.641. The latter were higher than the correlation coefficients between total score and exposure indicators, which ranged from 0.160 to 0.421. Correlations between individual indicators were low (-0.240 to 0.376), except for those between handling volume and distribution (0.613), suggesting that each indicator was not strongly correlated. The low correlations between each indicator mean that the indicators and independent and were well chosen for prioritizing harmful chemicals. This method proposed by this study can improve the cost efficiency of chemical management as utilized in occupational regulatory systems.

Positron emission tomography reveals correlations between brain metabolism and mood changes in hyperthyroidism.

PubMed

Schreckenberger, M F; Egle, U T; Drecker, S; Buchholz, H G; Weber, M M; Bartenstein, P; Kahaly, G J

2006-12-01

Hyperthyroidism is frequently associated with emotional distress. The underlying cerebral processes of the endocrine-induced mood changes are unclear. The objective of this study was to investigate, for the first time, the neuronal correlates of thyrotoxicosis-associated psychic symptoms using positron emission tomography (PET). The study was designed as a cross-sectional trial. The study was performed at joint nuclear medicine and thyroid clinics. Twelve patients with untreated Graves' hyperthyroidism were evaluated. Levels of emotional distress were self-rated by means of the Hospital Anxiety and Depression Scale. Both patients and 20 age- and gender-matched euthyroid controls underwent a brain fluorodeoxyglucose PET scan. Subsequently, the functional relationship between brain metabolism and the psychometric scores was analyzed. Compared with controls and visualized by fluorodeoxyglucose PET, hyperthyroid patients showed a decreased (P < 0.0001) glucose metabolism in the limbic system (uncus and inferior temporal gyrus). Activation foci in the posterior cingulate and in the inferior parietal lobe were correlated with both anxiety and depression scales (P < 0.001). Compared with patients with normal anxiety levels, those with increased anxiety yielded an enhanced glucose metabolism (P < 0.001) in the bilateral sensory association cortex. Serum free T3/free T4 levels negatively correlated with regional glucose metabolism in the medial posterior cingulate. Thyrotoxicosis and associated psychic symptoms are correlated to regional metabolic changes in the main structures of the limbic/paralimbic system.

Success Avoidant Motivation and Behavior; Its Development Correlates and Situational Determinants. Final Report.

ERIC Educational Resources Information Center

Horner, Matina S.

This paper reports on a successful attempt to understand success avoidant motivation and behavior by the development of an empirically sophisticated scoring system of success avoidant motivation and the observation of its behavioral correlates and situational determinants. Like most of the work on achievement motivation, the study was carried out…

An Investigation of Possible Correlations Between Individual Pilot Performance and Neurological Functions.

DTIC Science & Technology

1977-05-23

ed these findings with tests on peptic ulcer patients.1’ In 1949, Sau l , using a psychoanalytic approach in searching for correlates of personality...this area : PILOT PERFOR MANCE ANA L YSIS 1) With respect to the system developed and used for this study, research should be conducted to determine

Electron-mediated relaxation following ultrafast pumping of strongly correlated materials: model evidence of a correlation-tuned crossover between thermal and nonthermal states.

PubMed

Moritz, B; Kemper, A F; Sentef, M; Devereaux, T P; Freericks, J K

2013-08-16

We examine electron-electron mediated relaxation following ultrafast electric field pump excitation of the fermionic degrees of freedom in the Falicov-Kimball model for correlated electrons. The results reveal a dichotomy in the temporal evolution of the system as one tunes through the Mott metal-to-insulator transition: in the metallic regime relaxation can be characterized by evolution toward a steady state well described by Fermi-Dirac statistics with an increased effective temperature; however, in the insulating regime this quasithermal paradigm breaks down with relaxation toward a nonthermal state with a complicated electronic distribution as a function of momentum. We characterize the behavior by studying changes in the energy, photoemission response, and electronic distribution as functions of time. This relaxation may be observable qualitatively on short enough time scales that the electrons behave like an isolated system not in contact with additional degrees of freedom which would act as a thermal bath, especially when using strong driving fields and studying materials whose physics may manifest the effects of correlations.

The validation of the visual analogue scale for patient satisfaction after total hip arthroplasty.

PubMed

Brokelman, Roy B G; Haverkamp, Daniel; van Loon, Corné; Hol, Annemiek; van Kampen, Albert; Veth, Rene

2012-06-01

INTRODUCTION: Patient satisfaction becomes more important in our modern health care system. The assessment of satisfaction is difficult because it is a multifactorial item for which no golden standard exists. One of the potential methods of measuring satisfaction is by using the well-known visual analogue scale (VAS). In this study, we validated VAS for satisfaction. PATIENT AND METHODS: In this prospective study, we studied 147 patients (153 hips). The construct validity was measured using the Spearman correlation test that compares the satisfaction VAS with the Harris hip score, pain VAS at rest and during activity, Oxford hip score, Short Form 36 and Western Ontario McMaster Universities Osteoarthritis Index. The reliability was tested using the intra-class coefficient. RESULTS: The Pearson correlation test showed correlations in the range of 0.40-0.80. The satisfaction VAS had a high correlation between the pain VAS and Oxford hip score, which could mean that pain is one of the most important factors in patient satisfaction. The intra-class coefficient was 0.95. CONCLUSIONS: There is a moderate to mark degree of correlation between the satisfaction VAS and the currently available subjective and objective scoring systems. The intra-class coefficient of 0.95 indicates an excellent test-retest reliability. The VAS satisfaction is a simple instrument to quantify the satisfaction of a patient after total hip arthroplasty. In this study, we showed that the satisfaction VAS has a good validity and reliability.

State-Space System Realization with Input- and Output-Data Correlation

NASA Technical Reports Server (NTRS)

Juang, Jer-Nan

1997-01-01

This paper introduces a general version of the information matrix consisting of the autocorrelation and cross-correlation matrices of the shifted input and output data. Based on the concept of data correlation, a new system realization algorithm is developed to create a model directly from input and output data. The algorithm starts by computing a special type of correlation matrix derived from the information matrix. The special correlation matrix provides information on the system-observability matrix and the state-vector correlation. A system model is then developed from the observability matrix in conjunction with other algebraic manipulations. This approach leads to several different algorithms for computing system matrices for use in representing the system model. The relationship of the new algorithms with other realization algorithms in the time and frequency domains is established with matrix factorization of the information matrix. Several examples are given to illustrate the validity and usefulness of these new algorithms.

Phase transition in 2-d system of quadrupoles on square lattice with anisotropic field

NASA Astrophysics Data System (ADS)

Sallabi, A. K.; Alkhttab, M.

2014-12-01

Monte Carlo method is used to study a simple model of two-dimensional interacting quadrupoles on ionic square lattice with anisotropic strength provided by the ionic lattice. Order parameter, susceptibility and correlation function data, show that this system form an ordered structure with p(2×1) symmetry at low temperature. The p(2×1) structure undergoes an order-disorder phase transition into disordered (1×1) phase at 8.3K. The two-point correlation function show exponential dependence on distance both above and below the transition temperature. At Tc the two-point correlation function shows a power law dependence on distance, e.g. C(r) ~ 1η. The value of the exponent η at Tc shows small deviation from the Ising value and indicates that this system falls into the same universality class as the XY model with cubic anisotropy. This model can be applied to prototypical quadrupoles physisorbed systems as N2 on NaCl(100).

USAF Development Of Optical Correlation Missile Guidance

NASA Astrophysics Data System (ADS)

Kaehr, Ronald; Spector, Marvin

1980-12-01

In 1965, the Advanced Development Program (ADP)-679A of the Avionics Laboratory initiated development of guidance systems for stand-off tactical missiles. Employing project engineering support from the Aeronautical Systems Division, WPAFB, the Avionics Laboratory funded multiple terminal guidance concepts and related midcourse navigation technology. Optical correlation techniques which utilize prestored reference information for autonomous target acquisition offered the best near-term opportunity for meeting mission goals. From among the systems studied and flight tested, Aimpoint* optical area guidance provided the best and most consistent performance. Funded development by the Air Force ended in 1974 with a MK-84 guided bomb drop test demonstration at White Sands Missile Range and the subsequent transfer of the tactical missile guidance development charter to the Air Force Armament Laboratory, Eglin AFB. A historical review of optical correlation development within the Avionics Laboratory is presented. Evolution of the Aimpoint system is specifically addressed. Finally, a brief discussion of trends in scene matching technology is presented.

Long noncoding RNA MALAT1 as a potential novel biomarker in digestive system cancers: a meta-analysis.

PubMed

Song, Wei; Zhang, Run J; Zou, Shu B

2016-08-01

Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), a newly discovered long non-coding RNA (lncRNA), has been reported to be overexpressed in various cancers. However, the clinical value of MALAT1 in digestive system cancers is unclear. This study was designed to investigate the potential value of MALAT1 as a prognostic biomarker in digestive system cancers. We searched the Medline, Embase and Cochrane Library databases. All studies that explored the correlation between lncRNA MALAT1 expression and survival in digestive system tumors were selected. A quantitative meta-analysis was performed for the correlation between lncRNA MALAT1 expression and survival in digestive system tumors. Five studies were eligible for analysis, which included 547 patients. Meta-analysis showed that high expression of MALAT1 could predict poor overall survival (OS) in digestive system cancers (pooled HR: 1.85, 95% CI: 1.41-2.43, P<0.0001). For disease-free survival (DFS), elevated MALAT1 expression was also a significant predictor with a combined HR of 2.28 (95% CI: 1.42-3.67, P=0.0007). lncRNA MALAT1 may serve as a potential novel prognostic biomarker in digestive system cancers.

Long noncoding RNA MALAT1 as a potential novel biomarker in digestive system cancers: a meta-analysis.

PubMed

Song, Wei; Zhang, Run J; Zou, Shu B

2016-05-17

MALAT1 (Metastasis-associated lung adenocarcinoma transcript 1), a newly discovered long non-coding RNA (lncRNA), has been reported to be overexpressed in various cancers. However, the clinical value of MALAT1 in digestive system cancers is unclear. This study was designed to investigate the potential value of MALAT1 as a prognostic biomarker in digestive system cancers. We searched the MEDLINE, EMBASE and Cochrane Library databases. All studies that explored the correlation between lncRNA MALAT1 expression and survival in digestive system tumors were selected. A quantitative meta-analysis was performed for the correlation between lncRNA MALAT1 expression and survival in digestive system tumors. Five studies were eligible for analysis, which included 547 patients. Meta-analysis showed that high expression of MALAT1 could predict poor overall survival (OS) in digestive system cancers (pooled HR: 1.85, 95% CI: 1.41-2.43, p < 0.0001). For disease-free survival (DFS), elevated MALAT1 expression was also a significant predictor with a combined HR of 2.28 (95% CI: 1.42-3.67, p = 0.0007). lncRNA MALAT1 may serve as a potential novel prognostic biomarker in digestive system cancers.

Using the manual ability classification system in young adults with cerebral palsy and normal intelligence.

PubMed

van Meeteren, Jetty; Nieuwenhuijsen, Channah; de Grund, Arthur; Stam, Henk J; Roebroeck, Marij E

2010-01-01

The study aimed to establish whether the manual ability classification system (MACS), a valid classification system for manual ability in children with cerebral palsy (CP), is applicable in young adults with CP and normal intelligence. The participants (n = 83) were young adults with CP and normal intelligence and had a mean age of 19.9 years. In this study, inter observer reliability of the MACS was determined. We investigated relationships between the MACS level and patient characteristics (such as the gross motor function classification system (GMFCS) level, limb distribution of the spastic paresis and educational level) and with functional activities of the upper extremity (assessed with the Melbourne assessment, the Abilhand questionnaire and the domain self-care of the functional independence measure (FIM)). Furthermore, with a linear regression analysis it was determined whether the MACS is a significant determinant of activity limitations and participation restrictions. The reliability was good (intraclass correlation coefficient 0.83). The Spearman correlation coefficients with GMFCS level, limb distribution of the spastic paresis and educational level were 0.53, 0.46, and 0.26, respectively. MACS level correlated moderately with outcome measures of functional activities (correlations ranging from -0.38 to -0.55). MACS level is, in addition to the GMFCS level, an important determinant for limitations in activities and restrictions in participation. We conclude that the MACS is a feasible method to classify manual ability in young adults with CP and normal intelligence with a good manual ability.

The relationship of acquisition systems to automated stereo correlation.

USGS Publications Warehouse

Colvocoresses, A.P.

1983-01-01

Today a concerted effort is being made to expedite the mapping process through automated correlation of stereo data. Stereo correlation involves the comparison of radiance (brightness) signals or patterns recorded by sensors. Conventionally, two-dimensional area correlation is utilized but this is a rather slow and cumbersome procedure. Digital correlation can be performed in only one dimension where suitable signal patterns exist, and the one-dimensional mode is much faster. Electro-optical (EO) systems, suitable for space use, also have much greater flexibility than film systems. Thus, an EO space system can be designed which will optimize one-dimensional stereo correlation and lead toward the automation of topographic mapping.-from Author

Assessment of gait parameters and fatigue in MS patients during inpatient rehabilitation: a pilot trial.

PubMed

Sacco, Rosaria; Bussman, Rita; Oesch, Peter; Kesselring, Jürg; Beer, Serafin

2011-05-01

Gait impairment and fatigue are common and disabling problems in multiple sclerosis (MS). Characterisation of abnormal gait in MS patients has been done mainly using observational studies and simple walking tests providing only limited quantitative and no qualitative data, or using intricate and time-consuming assessment procedures. In addition, the correlation of gait impairments with fatigue is largely unknown. The aim of this study was to characterise spatio-temporal gait parameters by a simple and easy-to-use gait analysis system (GAITRite®) in MS patients compared with healthy controls, and to analyse changes and correlation with fatigue during inpatient rehabilitation. Twenty-four MS patients (EDSS <6.5) admitted for inpatient rehabilitation and 19 healthy subjects were evaluated using the GAITRite® Functional Ambulation System. Between-group differences and changes of gait parameters during inpatient rehabilitation were analysed, and correlation with fatigue, using the Wurzburg Fatigue Inventory for Multiple Sclerosis (WEIMuS), was determined. Compared to healthy controls MS patients showed significant impairments in different spatio-temporal gait parameters, which showed a significant improvement during inpatient rehabilitation. Different gait parameters were correlated with fatigue physical score, and change of gait parameters was correlated with improvement of fatigue. Spatio-temporal gait analysis is helpful to assess specific walking impairments in MS patients and subtle changes during rehabilitation. Correlation with fatigue may indicate a possible negative impact of fatigue on rehabilitation outcome.

Experimental studies of toroidal correlations of plasma density fluctuations along the magnetic field lines in the T-10 tokamak and first results of numerical modeling

NASA Astrophysics Data System (ADS)

Buldakov, M. A.; Vershkov, V. A.; Isaev, M. Yu; Shelukhin, D. A.

2017-10-01

The antenna system of reflectometry diagnostics at the T-10 tokamak allows to study long-range toroidal correlations of plasma density fluctuations along the magnetic field lines. The antenna systems are installed in two poloidal cross-sections of the vacuum chamber separated by a 90° angle in the toroidal direction. The experiments, which were conducted at the low field side, showed that the high level of toroidal correlations is observed only for quasi-coherent fluctuations. However, broadband and stochastic low frequency fluctuations are not correlated. Numerical modeling of the plasma turbulence structure in the T-10 tokamak was conducted to interpret the experimental results and take into account non-locality of reflectometry measurements. In the model used, it was assumed that the magnitudes of density fluctuations are constant along the magnetic field lines. The 2D full-wave Tamic-RTH code was used to model the reflectometry signals. High level of correlations for quasi-coherent fluctuations was obtained during the modeling, which agrees with the experimental observations. However, the performed modeling also predicts high level of correlations for broadband fluctuations, which contradicts the experimental data. The modeling showed that the effective reflection radius, from which the information on quasi-coherent plasma turbulence is obtained, is shifted outwards from the reflection radius by approximately 7 mm.

Non-Markovian Investigation of an Autonomous Quantum Heat Engine

NASA Astrophysics Data System (ADS)

Goyal, Ketan

A systematic study of a quantum heat engine is presented in this thesis. In particular, we study heat conduction through a two-two level composite system, which is then connected to a photon cavity to extract work, forming an autonomous quantum heat engine. The question as to what extent quantum effects such as quantum coherence and correlations impact thermodynamic properties of such a system is addressed. The investigated heat engine has been previously studied using the popular Born-Markovian quantum master equation under weak internal coupling approximation. However, we show that the used approach is quite limited in addressing such problems as it is incapable of correctly accounting for the quantum effects. By using a non-Markovian approach involving hierarchical equations of motion, we show that quantum coherence and correlations between system and environments play a significant role in energy transfer processes of heat conduction and work.

The Minnesota Grading System Using Fundus Autofluorescence of Eye Bank Eyes: A Correlation To Age-Related Macular Degeneration (An AOS Thesis)

PubMed Central

Olsen, Timothy W.

2008-01-01

Purpose To establish a grading system of eye bank eyes using fundus autofluorescence (FAF) and identify a methodology that correlates FAF to age-related macular degeneration (AMD) with clinical correlation to the Age-Related Eye Disease Study (AREDS). Methods Two hundred sixty-two eye bank eyes were evaluated using a standardized analysis of FAF. Measurements were taken with the confocal scanning laser ophthalmoscope (cSLO). First, high-resolution, digital, stereoscopic, color images were obtained and graded according to AREDS criteria. With the neurosensory retina removed, mean FAF values were obtained from cSLO images using software analysis that excludes areas of atrophy and other artifact, generating an FAF value from a grading template. Age and AMD grade were compared to FAF values. An internal fluorescence reference standard was tested. Results Standardization of the cSLO machine demonstrated that reliable data could be acquired after a 1-hour warm-up. Images obtained prior to 1 hour had falsely elevated levels of FAF. In this initial analysis, there was no statistical correlation of age to mean FAF. There was a statistically significant decrease in FAF from AREDS grade 1, 2 to 3, 4 (P < .0001). An internal fluorescent standard may serve as a quantitative reference. Conclusions The Minnesota Grading System (MGS) of FAF (MGS-FAF) establishes a standardized methodology for grading eye bank tissue to quantify FAF compounds in the retinal pigment epithelium and correlate these findings to the AREDS. Future studies could then correlate specific FAF to the aging process, histopathology AMD phenotypes, and other maculopathies, as well as to analyze the biochemistry of autofluorescent fluorophores. PMID:19277247

The Minnesota Grading System using fundus autofluorescence of eye bank eyes: a correlation to age-related macular degeneration (an AOS thesis).

PubMed

Olsen, Timothy W

2008-01-01

To establish a grading system of eye bank eyes using fundus autofluorescence (FAF) and identify a methodology that correlates FAF to age-related macular degeneration (AMD) with clinical correlation to the Age-Related Eye Disease Study (AREDS). Two hundred sixty-two eye bank eyes were evaluated using a standardized analysis of FAF. Measurements were taken with the confocal scanning laser ophthalmoscope (cSLO). First, high-resolution, digital, stereoscopic, color images were obtained and graded according to AREDS criteria. With the neurosensory retina removed, mean FAF values were obtained from cSLO images using software analysis that excludes areas of atrophy and other artifact, generating an FAF value from a grading template. Age and AMD grade were compared to FAF values. An internal fluorescence reference standard was tested. Standardization of the cSLO machine demonstrated that reliable data could be acquired after a 1-hour warm-up. Images obtained prior to 1 hour had falsely elevated levels of FAF. In this initial analysis, there was no statistical correlation of age to mean FAF. There was a statistically significant decrease in FAF from AREDS grade 1, 2 to 3, 4 (P < .0001). An internal fluorescent standard may serve as a quantitative reference. The Minnesota Grading System (MGS) of FAF (MGS-FAF) establishes a standardized methodology for grading eye bank tissue to quantify FAF compounds in the retinal pigment epithelium and correlate these findings to the AREDS. Future studies could then correlate specific FAF to the aging process, histopathology AMD phenotypes, and other maculopathies, as well as to analyze the biochemistry of autofluorescent fluorophores.

The reference ballistic imaging database revisited.

PubMed

De Ceuster, Jan; Dujardin, Sylvain

2015-03-01

A reference ballistic image database (RBID) contains images of cartridge cases fired in firearms that are in circulation: a ballistic fingerprint database. The performance of an RBID was investigated a decade ago by De Kinder et al. using IBIS(®) Heritage™ technology. The results of that study were published in this journal, issue 214. Since then, technologies have evolved quite significantly and novel apparatus have become available on the market. The current research article investigates the efficiency of another automated ballistic imaging system, Evofinder(®) using the same database as used by De Kinder et al. The results demonstrate a significant increase in correlation efficiency: 38% of all matches were on first position of the Evofinder correlation list in comparison to IBIS(®) Heritage™ where only 19% were on the first position. Average correlation times are comparable to the IBIS(®) Heritage™ system. While Evofinder(®) demonstrates specific improvement for mutually correlating different ammunition brands, ammunition dependence of the markings is still strongly influencing the correlation result because the markings may vary considerably. As a consequence a great deal of potential hits (36%) was still far down in the correlation lists (positions 31 and lower). The large database was used to examine the probability of finding a match as a function of correlation list verification. As an example, the RBID study on Evofinder(®) demonstrates that to find at least 90% of all potential matches, at least 43% of the items in the database need to be compared on screen and this for breech face markings and firing pin impression separately. These results, although a clear improvement to the original RBID study, indicate that the implementation of such a database should still not be considered nowadays. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Parameters of the Immune System and Vitamin D Levels in Old Individuals.

PubMed

Alves, Amanda Soares; Ishimura, Mayari Eika; Duarte, Yeda Aparecida de Oliveira; Bueno, Valquiria

2018-01-01

The increased number of individuals older than 80 years, centenarians, and supercentenarians is not a synonym for healthy aging, since severe infections, hospitalization, and disability are frequently observed. In this context, a possible strategy is to preserve the main characteristics/functions of the immune system with the aim to cause less damage to the organism during the aging process. Vitamin D acts on bone marrow, brain, breast, malignant cells, and immune system and has been recommended as a supplement. We aimed to evaluate whether immune parameters and vitamin D serum levels are correlated. We evaluated some features of the immune system using the peripheral blood of individuals older than 80 years ( n  = 12) compared to young subjects ( n  = 10). In addition, we correlated these findings with vitamin D serum levels. Old individuals presented metabolic parameters of healthy aging and maintained preserved some features of immunity such as CD4/CD8 ratio, and low production of pro-inflammatory cytokines after stimulus. On the other hand, we observed increase in the frequency of myeloid-derived suppressor cells, reduction in circulating leukocytes, in the percentage of total CD8+, and in CD8+ Naïve T cells, in addition to increase in the percentage of CD8+ effector memory re-expressing CD45RA (EMRA) T cells. We found seropositivity for CMV in 97.7%, which was correlated with the decrease of CD8+ Naïve T cells and increase in CD8+ EMRA T cells. Vitamin D levels were insufficient in 50% of old individuals and correlated positively with total CD8+ T cells and negatively with CD8+ EMRA T cells. In the studied population, longevity was correlated to maintenance of some immune parameters. Considering the limitations of the study as size of the sample and lack of functional assays, it was found that vitamin D in old individuals was correlated to some features of the immune system, mainly in the CD8 compartment.

The dimensionality reduction at surfaces as a playground for many-body and correlation effects

NASA Astrophysics Data System (ADS)

Tejeda, A.; Michel, E. G.; Mascaraque, A.

2013-03-01

Low-dimensional systems have always deserved attention due to the peculiarity of their physics, which is different from or even at odds with three-dimensional expectations. This is precisely the case for many-body effects, as electron-electron correlation or electron-phonon coupling are behind many intriguing problems in condensed matter physics. These interesting phenomena at low dimensions can be studied in one of the paradigms of two dimensionality—the surface of crystals. The maturity of today's surface science techniques allows us to perform thorough experimental studies that can be complemented by the current strength of state-of-the-art calculations. Surfaces are thus a natural two-dimensional playground for studying correlation and many-body effects, which is precisely the object of this special section. This special section presents a collection of eight invited articles, giving an overview of the current status of selected systems, promising techniques and theoretical approaches for studying many-body effects at surfaces and low-dimensional systems. The first article by Hofmann investigates electron-phonon coupling in quasi-free-standing graphene by decoupling graphene from two different substrates with different intercalating materials. The following article by Kirschner deals with the study of NiO films by electron pair emission, a technique particularly well-adapted for studying high electron correlation. Bovensiepen investigates electron-phonon coupling via the femtosecond time- and angle-resolved photoemission spectroscopy technique. The next article by Malterre analyses the phase diagram of alkalis on Si(111):B and studies the role of many-body physics. Biermann proposes an extended Hubbard model for the series of C, Si, Sn and Pb adatoms on Si(111) and obtains the inter-electronic interaction parameters by first principles. Continuing with the theoretical studies, Bechstedt analyses the influence of on-site electron correlation in insulating antiferromagnetic surfaces. Ortega reports on the gap of molecular layers on metal systems, where the metal-organic interaction affects the organic gap through correlation effects. Finally, Cazalilla presents a study of the phase diagram of one-dimensional atoms or molecules displaying a Kondo-exchange interaction with the substrate. Acknowledgments The editors are grateful to all the invited contributors to this special section of Journal of Physics: Condensed Matter. We also thank the IOP Publishing staff for handling the administrative matters and the refereeing process. Correlation and many-body effects at surfaces contents The dimensionality reduction at surfaces as a playground for many-body and correlation effectsA Tejeda, E G Michel and A Mascaraque Electron-phonon coupling in quasi-free-standing grapheneJens Christian Johannsen, Søren Ulstrup, Marco Bianchi, Richard Hatch, Dandan Guan, Federico Mazzola, Liv Hornekær, Felix Fromm, Christian Raidel, Thomas Seyller and Philip Hofmann Exploring highly correlated materials via electron pair emission: the case of NiO/Ag(100)F O Schumann, L Behnke, C H Li and J Kirschner Coherent excitations and electron-phonon coupling in Ba/EuFe2As2 compounds investigated by femtosecond time- and angle-resolved photoemission spectroscopyI Avigo, R Cortés, L Rettig, S Thirupathaiah, H S Jeevan, P Gegenwart, T Wolf, M Ligges, M Wolf, J Fink and U Bovensiepen Understanding the insulating nature of alkali-metal/Si(111):B interfacesY Fagot-Revurat, C Tournier-Colletta, L Chaput, A Tejeda, L Cardenas, B Kierren, D Malterre, P Le Fèvre, F Bertran and A Taleb-Ibrahimi What about U on surfaces? Extended Hubbard models for adatom systems from first principlesPhilipp Hansmann, Loïg Vaugier, Hong Jiang and Silke Biermann Influence of on-site Coulomb interaction U on properties of MnO(001)2 × 1 and NiO(001)2 × 1 surfacesA Schrön, M Granovskij and F Bechstedt On the organic energy gap problemF Flores, E Abad, J I Martínez, B Pieczyrak and J Ortega Easy-axis ferromagnetic chain on a metallic surfaceMiguel A Cazalilla

Identifying Optimal Temporal Scale for the Correlation of AOD and Ground Measurements of PM2.5 to Improve the Modeling Performance in a Real-Time Air Quality Estimation System

NASA Technical Reports Server (NTRS)

Li,Hui; Faruque, Fazlay; Williams, Worth; Al-Hamdan, Mohammad; Luvall, Jeffrey; Crosson, William; Rickman, Douglas; Limaye, Ashutosh

2008-01-01

Aerosol optical depth (AOD), derived from satellite measurements using Moderate Resolution Imaging Spectrometer (MODIS), offers indirect estimates of particle matter. Research shows a significant positive correlation between satellite-based measurements of AOD and ground-based measurements of particulate matter with aerodynamic diameter less than or equal to 2.5 micrometers (PM2.5). In addition, satellite observations have also shown great promise in improving estimates of PM2.5 air quality surface. Research shows that correlations between AOD and ground PM2.5 are affected by a combination of many factors such as inherent characteristics of satellite observations, terrain, cloud cover, height of the mixing layer, and weather conditions, and thus might vary widely in different regions, different seasons, and even different days in a same location. Analysis of correlating AOD with ground measured PM2.5 on a day-to-day basis suggests the temporal scale, a number of immediate latest days for a given run's day, for their correlations needs to be considered to improve air quality surface estimates, especially when satellite observations are used in a real-time pollution system. The second reason is that correlation coefficients between AOD and ground PM2.5 cannot be predetermined and needs to be calculated for each day's run for a real-time system because the coefficients can vary over space and time. Few studies have been conducted to explore the optimal way to apply AOD data to improve model accuracies of PM2.5 surface estimation in a real-time air quality system. This paper discusses the best temporal scale to calculate the correlation of AOD and ground particle matter data to improve the results of pollution models in real-time system.

Role of the Pair Correlation Function in the Dynamical Transition Predicted by Mode Coupling Theory

NASA Astrophysics Data System (ADS)

Nandi, Manoj Kumar; Banerjee, Atreyee; Dasgupta, Chandan; Bhattacharyya, Sarika Maitra

2017-12-01

In a recent study, we have found that for a large number of systems the configurational entropy at the pair level Sc 2, which is primarily determined by the pair correlation function, vanishes at the dynamical transition temperature Tc. Thus, it appears that the information of the transition temperature is embedded in the structure of the liquid. In order to investigate this, we describe the dynamics of the system at the mean field level and, using the concepts of the dynamical density functional theory, show that the dynamical transition temperature depends only on the pair correlation function. Thus, this theory is similar in spirit to the microscopic mode coupling theory (MCT). However, unlike microscopic MCT, which predicts a very high transition temperature, the present theory predicts a transition temperature that is similar to Tc. This implies that the information of the dynamical transition temperature is embedded in the pair correlation function.

Spatial correlation analysis of cascading failures: Congestions and Blackouts

PubMed Central

Daqing, Li; Yinan, Jiang; Rui, Kang; Havlin, Shlomo

2014-01-01

Cascading failures have become major threats to network robustness due to their potential catastrophic consequences, where local perturbations can induce global propagation of failures. Unlike failures spreading via direct contacts due to structural interdependencies, overload failures usually propagate through collective interactions among system components. Despite the critical need in developing protection or mitigation strategies in networks such as power grids and transportation, the propagation behavior of cascading failures is essentially unknown. Here we find by analyzing our collected data that jams in city traffic and faults in power grid are spatially long-range correlated with correlations decaying slowly with distance. Moreover, we find in the daily traffic, that the correlation length increases dramatically and reaches maximum, when morning or evening rush hour is approaching. Our study can impact all efforts towards improving actively system resilience ranging from evaluation of design schemes, development of protection strategies to implementation of mitigation programs. PMID:24946927

Environmental Lead Pollution in an Urban Soft-water Area

PubMed Central

Beattie, A. D.; Moore, M. R.; Devenay, W. T.; Miller, A. R.; Goldberg, A.

1972-01-01

An investigation has been reported on the clinical and metabolic effects of lead acquired by soft domestic water from lead plumbing systems in 23 Glasgow households. The lead content of water from cold taps was up to 18 times the upper acceptable limit and was proportional to the amount of lead in the plumbing system. The blood lead of 71 inhabitants of these houses showed a significant positive correlation with water lead content. Delta-aminolaevulic acid dehydrase activity, an extremely sensitive indicator of lead exposure, showed a significant negative correlation with water-lead content. Atmospheric lead was within acceptable limits in all but one house and no significant correlation could be found with biochemical measurements. A small number of clinical abnormalities were found but could not be directly attributed to lead toxicity. The results of the study underline the possible danger to health of lead plumbing systems in soft-water regions. PMID:5031207

Finite-size effects on current correlation functions

NASA Astrophysics Data System (ADS)

Chen, Shunda; Zhang, Yong; Wang, Jiao; Zhao, Hong

2014-02-01

We study why the calculation of current correlation functions (CCFs) still suffers from finite-size effects even when the periodic boundary condition is taken. Two important one-dimensional, momentum-conserving systems are investigated as examples. Intriguingly, it is found that the state of a system recurs in the sense of microcanonical ensemble average, and such recurrence may result in oscillations in CCFs. Meanwhile, we find that the sound mode collisions induce an extra time decay in a current so that its correlation function decays faster (slower) in a smaller (larger) system. Based on these two unveiled mechanisms, a procedure for correctly evaluating the decay rate of a CCF is proposed, with which our analysis suggests that the global energy CCF decays as ˜t-2/3 in the diatomic hard-core gas model and in a manner close to ˜t-1/2 in the Fermi-Pasta-Ulam-β model.

Strong correlation induced charge localization in antiferromagnets

PubMed Central

Zhu, Zheng; Jiang, Hong-Chen; Qi, Yang; Tian, Chushun; Weng, Zheng-Yu

2013-01-01

The fate of a hole injected in an antiferromagnet is an outstanding issue of strongly correlated physics. It provides important insights into doped Mott insulators closely related to high-temperature superconductivity. Here, we report a systematic numerical study of t-J ladder systems based on the density matrix renormalization group. It reveals a surprising result for the single hole's motion in an otherwise well-understood undoped system. Specifically, we find that the common belief of quasiparticle picture is invalidated by the self-localization of the doped hole. In contrast to Anderson localization caused by disorders, the charge localization discovered here is an entirely new phenomenon purely of strong correlation origin. It results from destructive quantum interference of novel signs picked up by the hole, and since the same effect is of a generic feature of doped Mott physics, our findings unveil a new paradigm which may go beyond the single hole doped system. PMID:24002668

Measuring Out-of-Time-Order Correlators on a Nuclear Magnetic Resonance Quantum Simulator

NASA Astrophysics Data System (ADS)

Li, Jun; Fan, Ruihua; Wang, Hengyan; Ye, Bingtian; Zeng, Bei; Zhai, Hui; Peng, Xinhua; Du, Jiangfeng

2017-07-01

The idea of the out-of-time-order correlator (OTOC) has recently emerged in the study of both condensed matter systems and gravitational systems. It not only plays a key role in investigating the holographic duality between a strongly interacting quantum system and a gravitational system, it also diagnoses the chaotic behavior of many-body quantum systems and characterizes information scrambling. Based on OTOCs, three different concepts—quantum chaos, holographic duality, and information scrambling—are found to be intimately related to each other. Despite its theoretical importance, the experimental measurement of the OTOC is quite challenging, and thus far there is no experimental measurement of the OTOC for local operators. Here, we report the measurement of OTOCs of local operators for an Ising spin chain on a nuclear magnetic resonance quantum simulator. We observe that the OTOC behaves differently in the integrable and nonintegrable cases. Based on the recent discovered relationship between OTOCs and the growth of entanglement entropy in the many-body system, we extract the entanglement entropy from the measured OTOCs, which clearly shows that the information entropy oscillates in time for integrable models and scrambles for nonintgrable models. With the measured OTOCs, we also obtain the experimental result of the butterfly velocity, which measures the speed of correlation propagation. Our experiment paves a way for experimentally studying quantum chaos, holographic duality, and information scrambling in many-body quantum systems with quantum simulators.

Computing Earthquake Probabilities on Global Scales

NASA Astrophysics Data System (ADS)

Holliday, James R.; Graves, William R.; Rundle, John B.; Turcotte, Donald L.

2016-03-01

Large devastating events in systems such as earthquakes, typhoons, market crashes, electricity grid blackouts, floods, droughts, wars and conflicts, and landslides can be unexpected and devastating. Events in many of these systems display frequency-size statistics that are power laws. Previously, we presented a new method for calculating probabilities for large events in systems such as these. This method counts the number of small events since the last large event and then converts this count into a probability by using a Weibull probability law. We applied this method to the calculation of large earthquake probabilities in California-Nevada, USA. In that study, we considered a fixed geographic region and assumed that all earthquakes within that region, large magnitudes as well as small, were perfectly correlated. In the present article, we extend this model to systems in which the events have a finite correlation length. We modify our previous results by employing the correlation function for near mean field systems having long-range interactions, an example of which is earthquakes and elastic interactions. We then construct an application of the method and show examples of computed earthquake probabilities.

System Biology Approach: Gene Network Analysis for Muscular Dystrophy.

PubMed

Censi, Federica; Calcagnini, Giovanni; Mattei, Eugenio; Giuliani, Alessandro

2018-01-01

Phenotypic changes at different organization levels from cell to entire organism are associated to changes in the pattern of gene expression. These changes involve the entire genome expression pattern and heavily rely upon correlation patterns among genes. The classical approach used to analyze gene expression data builds upon the application of supervised statistical techniques to detect genes differentially expressed among two or more phenotypes (e.g., normal vs. disease). The use of an a posteriori, unsupervised approach based on principal component analysis (PCA) and the subsequent construction of gene correlation networks can shed a light on unexpected behaviour of gene regulation system while maintaining a more naturalistic view on the studied system.In this chapter we applied an unsupervised method to discriminate DMD patient and controls. The genes having the highest absolute scores in the discrimination between the groups were then analyzed in terms of gene expression networks, on the basis of their mutual correlation in the two groups. The correlation network structures suggest two different modes of gene regulation in the two groups, reminiscent of important aspects of DMD pathogenesis.

Heralding efficiency and correlated-mode coupling of near-IR fiber-coupled photon pairs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dixon, P. Ben; Rosenberg, Danna; Stelmakh, Veronika

We report on a systematic experimental study of heralding efficiency and generation rate of telecom-band infrared photon pairs generated by spontaneous parametric down-conversion and coupled to single mode optical fibers. We define the correlated-mode coupling efficiency--an inherent source efficiency--and explain its relation to heralding efficiency. For our experiment, we developed a reconfigurable computer controlled pump-beam and collection-mode optical apparatus which we used to measure the generation rate and correlated-mode coupling efficiency. The use of low-noise, high-efficiency superconducting-nanowire single-photon-detectors in this setup allowed us to explore focus configurations with low overall photon flux. The measured data agree well with theory andmore » we demonstrated a correlated-mode coupling efficiency of 97%±2%, which is the highest efficiency yet achieved for this type of system. These results confirm theoretical treatments and demonstrate that very high overall heralding efficiencies can, in principle, be achieved in quantum optical systems. We expect that these results and techniques will be widely incorporated into future systems that require, or benefit from, a high heralding efficiency.« less

Heralding efficiency and correlated-mode coupling of near-IR fiber-coupled photon pairs

DOE PAGES

Dixon, P. Ben; Rosenberg, Danna; Stelmakh, Veronika; ...

2014-10-06

We report on a systematic experimental study of heralding efficiency and generation rate of telecom-band infrared photon pairs generated by spontaneous parametric down-conversion and coupled to single mode optical fibers. We define the correlated-mode coupling efficiency--an inherent source efficiency--and explain its relation to heralding efficiency. For our experiment, we developed a reconfigurable computer controlled pump-beam and collection-mode optical apparatus which we used to measure the generation rate and correlated-mode coupling efficiency. The use of low-noise, high-efficiency superconducting-nanowire single-photon-detectors in this setup allowed us to explore focus configurations with low overall photon flux. The measured data agree well with theory andmore » we demonstrated a correlated-mode coupling efficiency of 97%±2%, which is the highest efficiency yet achieved for this type of system. These results confirm theoretical treatments and demonstrate that very high overall heralding efficiencies can, in principle, be achieved in quantum optical systems. We expect that these results and techniques will be widely incorporated into future systems that require, or benefit from, a high heralding efficiency.« less

In-space propellant logistics. Volume 1: Executive summary

NASA Technical Reports Server (NTRS)

1972-01-01

The study addresses the systems and operational problems associated with the transport, transfer, and storage of cryogenic propellants in low earth orbits. The safety problems connected with in-space propellant logistics operations are also considered.Correlation between the two projects was maintained by including safety considerations, resulting from the system safety analysis, in the trade studies and evaluations of alternate operating concepts in the systems operations analysis.

Computing physical properties with quantum Monte Carlo methods with statistical fluctuations independent of system size.

PubMed

Assaraf, Roland

2014-12-01

We show that the recently proposed correlated sampling without reweighting procedure extends the locality (asymptotic independence of the system size) of a physical property to the statistical fluctuations of its estimator. This makes the approach potentially vastly more efficient for computing space-localized properties in large systems compared with standard correlated methods. A proof is given for a large collection of noninteracting fragments. Calculations on hydrogen chains suggest that this behavior holds not only for systems displaying short-range correlations, but also for systems with long-range correlations.

Correlates of monoicy and dioicy in hornworts, the apparent sister group to vascular plants.

PubMed

Villarreal, Juan Carlos; Renner, Susanne S

2013-11-02

Whether male and female gametes are produced by single or separate individuals shapes plant mating and hence patterns of genetic diversity among and within populations. Haploid-dominant plants ("bryophytes": liverworts, mosses and hornworts) can have unisexual (dioicous) or bisexual (monoicous) gametophytes, and today, 68% of liverwort species, 57% of moss species, and 40% of hornwort species are dioicous. The transitions between the two sexual systems and possible correlations with other traits have been studied in liverworts and mosses, but not hornworts. Here we use a phylogeny for 98 of the 200 species of hornworts, the sister group to vascular plants, representing roughly equal proportions of all monoicous and all dioicous species, to test whether transitions in sexual systems are predominantly from monoicy to dioicy as might be expected based on studies of mosses. We further investigate possible correlations between sexual system and spore size, antheridium number, ploidy level, and diversification rate, with character selection partly based on findings in mosses and liverworts. Hornworts underwent numerous transitions between monoicy and dioicy. The transition rate from dioicy to monoicy was 2× higher than in the opposite direction, but monoicous groups have higher extinction rates; diversification rates do not correlate with sexual system. A correlation important in mosses, that between monoicy and polyploidy, apparently plays a small role: of 20 species with chromosome counts, only one is polyploid, the monoicous Anthoceros punctatus. A contingency test revealed that transitions to dioicy were more likely in species with small spores, supporting the hypothesis that small but numerous spores may be advantageous for dioicous species that depend on dense carpets of gametophytes for reproductive assurance. However, we found no evidence for increased antheridium-per-chamber numbers in dioicous species. Sexual systems in hornworts are labile, and the higher number of extant monoicous species (60%) may be largely due to frequent transitions to monoicy.

White matter lesions and brain atrophy in systemic lupus erythematosus patients: correlation to cognitive dysfunction in a cohort of systemic lupus erythematosus patients using different definition models for neuropsychiatric systemic lupus erythematosus.

PubMed

Cannerfelt, B; Nystedt, J; Jönsen, A; Lätt, J; van Westen, D; Lilja, A; Bengtsson, A; Nilsson, P; Mårtensson, J; Sundgren, P C

2018-06-01

Aim The aim of this study was to evaluate the extent of white matter lesions, atrophy of the hippocampus and corpus callosum, and their correlation with cognitive dysfunction (CD), in patients diagnosed with systemic lupus erythematosus (SLE). Methods Seventy SLE patients and 25 healthy individuals (HIs) were included in the study. To evaluate the different SLE and neuropsychiatric SLE (NPSLE) definition schemes, patients were grouped both according to the American College of Rheumatology (ACR) definition, as well as the more stringent ACR-Systemic Lupus International Collaborating Clinics definition. Patients and HIs underwent a 3 Tesla brain MRI and a standardized neuropsychological test. MRI data were evaluated for number and volume of white matter lesions and atrophy of the hippocampus and corpus callosum. Differences between groups and subgroups were evaluated for significance. Number and volume of white matter lesions and atrophy of the hippocampus and corpus callosum were correlated to cognitive dysfunction. Results The total volume of white matter lesions was significantly larger in SLE patients compared to HIs ( p = 0.004). However, no significant differences were seen between the different SLE subgroups. Atrophy of the bilateral hippocampus was significantly more pronounced in patients with NPSLE compared to those with non-NPSLE (right: p = 0.010; left p = 0.023). Significant negative correlations between cognitive test scores on verbal memory and number and volume of white matter lesions were present. Conclusion SLE patients have a significantly larger volume of white matter lesions on MRI compared to HIs and the degree of white matter lesion volume correlates to cognitive dysfunction, specifically to verbal memory. No significant differences in the number or volume of white matter lesions were identified between subgroups of SLE patients regardless of the definition model used.

Hybrid associative memory using an incoherent correlation system

NASA Astrophysics Data System (ADS)

Taniguchi, Masaki; Ichioka, Yoshiki; Matsuoka, Katsunori

1990-10-01

A hybrid heteroassociative memory is presented that uses an incoherent system in which two correlators and a nonlinear element form a nonlinear feedback system. This system can recall any pattern from an input pattern without cross-talk or ghosts by properly designing a pair of filters installed in the correlators. Experiments on a simple hybrid system were performed to ensure the operation of the system and to demonstrate the usefulness of this proposed system.

Experimental results for correlation-based wavefront sensing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poyneer, L A; Palmer, D W; LaFortune, K N

2005-07-01

Correlation wave-front sensing can improve Adaptive Optics (AO) system performance in two keys areas. For point-source-based AO systems, Correlation is more accurate, more robust to changing conditions and provides lower noise than a centroiding algorithm. Experimental results from the Lick AO system and the SSHCL laser AO system confirm this. For remote imaging, Correlation enables the use of extended objects for wave-front sensing. Results from short horizontal-path experiments will show algorithm properties and requirements.

Evidence for Collective Multiparticle Correlations in p-Pb Collisions.

PubMed

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Donegà, M; Dünser, M; Eller, P; Grab, C; Hits, D; Hoss, J; Kasieczka, G; Lustermann, W; Mangano, B; Marini, A C; Marionneau, M; Martinez Ruiz del Arbol, P; Masciovecchio, M; Meister, D; Mohr, N; Musella, P; Nägeli, C; Nessi-Tedaldi, F; Pandolfi, F; Pauss, F; Perrozzi, L; Peruzzi, M; Quittnat, M; Rebane, L; Rossini, M; Starodumov, A; Takahashi, M; Theofilatos, K; Wallny, R; Weber, H A; Amsler, C; Canelli, M F; Chiochia, V; De Cosa, A; Hinzmann, A; Hreus, T; Kilminster, B; Lange, C; Ngadiuba, J; Pinna, D; Robmann, P; Ronga, F J; Taroni, S; Yang, Y; Cardaci, M; Chen, K H; Ferro, C; Kuo, C M; Lin, W; Lu, Y J; Volpe, R; Yu, S S; Chang, P; Chang, Y H; Chao, Y; Chen, K F; Chen, P H; Dietz, C; Grundler, U; Hou, W-S; Liu, Y F; Lu, R-S; Miñano Moya, M; Petrakou, E; Tsai, J F; Tzeng, Y M; Wilken, R; Asavapibhop, B; Singh, G; Srimanobhas, N; Suwonjandee, N; Adiguzel, A; Bakirci, M N; Cerci, S; Dozen, C; Dumanoglu, I; Eskut, E; Girgis, S; Gokbulut, G; Guler, Y; Gurpinar, E; Hos, I; Kangal, E E; Kayis Topaksu, A; Onengut, G; Ozdemir, K; Ozturk, S; Polatoz, A; Sunar Cerci, D; Tali, B; Topakli, H; Vergili, M; Zorbilmez, C; Akin, I V; Bilin, B; Bilmis, S; Gamsizkan, H; Isildak, B; Karapinar, G; Ocalan, K; Sekmen, S; Surat, U E; Yalvac, M; Zeyrek, M; Albayrak, E A; Gülmez, E; Kaya, M; Kaya, O; Yetkin, T; Cankocak, K; Vardarlı, F I; Levchuk, L; Sorokin, P; Brooke, J J; Clement, E; Cussans, D; Flacher, H; Goldstein, J; Grimes, M; Heath, G P; Heath, H F; Jacob, J; Kreczko, L; Lucas, C; Meng, Z; Newbold, D M; Paramesvaran, S; Poll, A; Sakuma, T; Seif El Nasr-Storey, S; Senkin, S; Smith, V J; Belyaev, A; Brew, C; Brown, R M; Cockerill, D J A; Coughlan, J A; Harder, K; Harper, S; Olaiya, E; Petyt, D; Shepherd-Themistocleous, C H; Thea, A; Tomalin, I R; Williams, T; Womersley, W J; Worm, S D; Baber, M; Bainbridge, R; Buchmuller, O; Burton, D; Colling, D; Cripps, N; Dauncey, P; Davies, G; Della Negra, M; Dunne, P; Elwood, A; Ferguson, W; Fulcher, J; Futyan, D; Hall, G; Iles, G; Jarvis, M; Karapostoli, G; Kenzie, M; Lane, R; Lucas, R; Lyons, L; Magnan, A-M; Malik, S; Mathias, B; Nash, J; Nikitenko, A; Pela, J; Pesaresi, M; Petridis, K; Raymond, D M; Rogerson, S; Rose, A; Seez, C; Sharp, P; Tapper, A; Vazquez Acosta, M; Virdee, T; Zenz, S C; Cole, J E; Hobson, P R; Khan, A; Kyberd, P; Leggat, D; Leslie, D; Reid, I D; Symonds, P; Teodorescu, L; Turner, M; Dittmann, J; Hatakeyama, K; Kasmi, A; Liu, H; Pastika, N; Scarborough, T; Wu, Z; Charaf, O; Cooper, S I; Henderson, C; Rumerio, P; Avetisyan, A; Bose, T; Fantasia, C; Lawson, P; Richardson, C; Rohlf, J; St John, J; Sulak, L; Alimena, J; Berry, E; Bhattacharya, S; Christopher, G; Cutts, D; Demiragli, Z; Dhingra, N; Ferapontov, A; Garabedian, A; Heintz, U; Laird, E; Landsberg, G; Mao, Z; Narain, M; Sagir, S; Sinthuprasith, T; Speer, T; Swanson, J; Breedon, R; Breto, G; Calderon De La Barca Sanchez, M; Chauhan, S; Chertok, M; Conway, J; Conway, R; Cox, P T; Erbacher, R; Gardner, M; Ko, W; Lander, R; Mulhearn, M; Pellett, D; Pilot, J; Ricci-Tam, F; Shalhout, S; Smith, J; Squires, M; Stolp, D; Tripathi, M; Wilbur, S; Yohay, R; Cousins, R; Everaerts, P; Farrell, C; Hauser, J; Ignatenko, M; Rakness, G; Takasugi, E; Valuev, V; Weber, M; Burt, K; Clare, R; Ellison, J; Gary, J W; Hanson, G; Heilman, J; Ivova Rikova, M; Jandir, P; Kennedy, E; Lacroix, F; Long, O R; Luthra, A; Malberti, M; Olmedo Negrete, M; Shrinivas, A; Sumowidagdo, S; Wimpenny, S; Branson, J G; Cerati, G B; Cittolin, S; D'Agnolo, R T; Holzner, A; Kelley, R; Klein, D; Letts, J; Macneill, I; Olivito, D; Padhi, S; Palmer, C; Pieri, M; Sani, M; Sharma, V; Simon, S; Tadel, M; Tu, Y; Vartak, A; Welke, C; Würthwein, F; Yagil, A; Zevi Della Porta, G; Barge, D; Bradmiller-Feld, J; Campagnari, C; Danielson, T; Dishaw, A; Dutta, V; Flowers, K; Franco Sevilla, M; Geffert, P; George, C; Golf, F; Gouskos, L; Incandela, J; Justus, C; Mccoll, N; Mullin, S D; Richman, J; Stuart, D; To, W; West, C; Yoo, J; Apresyan, A; Bornheim, A; Bunn, J; Chen, Y; Duarte, J; Mott, A; Newman, H B; Pena, C; Pierini, M; Spiropulu, M; Vlimant, J R; Wilkinson, R; Xie, S; Zhu, R Y; Azzolini, V; Calamba, A; Carlson, B; Ferguson, T; Iiyama, Y; Paulini, M; Russ, J; Vogel, H; Vorobiev, I; Cumalat, J P; Ford, W T; Gaz, A; Krohn, M; Luiggi Lopez, E; Nauenberg, U; Smith, J G; Stenson, K; Wagner, S R; Alexander, J; Chatterjee, A; Chaves, J; Chu, J; Dittmer, S; Eggert, N; Mirman, N; Nicolas Kaufman, G; Patterson, J R; Ryd, A; Salvati, E; Skinnari, L; Sun, W; Teo, W D; Thom, J; Thompson, J; Tucker, J; Weng, Y; Winstrom, L; Wittich, P; Winn, D; Abdullin, S; Albrow, M; Anderson, J; Apollinari, G; Bauerdick, L A T; Beretvas, A; Berryhill, J; Bhat, P C; Bolla, G; Burkett, K; Butler, J N; Cheung, H W K; Chlebana, F; Cihangir, S; Elvira, V D; Fisk, I; Freeman, J; Gottschalk, E; Gray, L; Green, D; Grünendahl, S; Gutsche, O; Hanlon, J; Hare, D; Harris, R M; Hirschauer, J; Hooberman, B; Jindariani, S; Johnson, M; Joshi, U; Klima, B; Kreis, B; Kwan, S; Linacre, J; Lincoln, D; Lipton, R; Liu, T; Lopes De Sá, R; Lykken, J; Maeshima, K; Marraffino, J M; Martinez Outschoorn, V I; Maruyama, S; Mason, D; McBride, P; Merkel, P; Mishra, K; Mrenna, S; Nahn, S; Newman-Holmes, C; O'Dell, V; Prokofyev, O; Sexton-Kennedy, E; Soha, A; Spalding, W J; Spiegel, L; Taylor, L; Tkaczyk, S; Tran, N V; Uplegger, L; Vaandering, E W; Vidal, R; Whitbeck, A; Whitmore, J; Yang, F; Acosta, D; Avery, P; Bortignon, P; Bourilkov, D; Carver, M; Curry, D; Das, S; De Gruttola, M; Di Giovanni, G P; Field, R D; Fisher, M; Furic, I K; Hugon, J; Konigsberg, J; Korytov, A; Kypreos, T; Low, J F; Matchev, K; Mei, H; Milenovic, P; Mitselmakher, G; Muniz, L; Rinkevicius, A; Shchutska, L; Snowball, M; Sperka, D; Yelton, J; Zakaria, M; Hewamanage, S; Linn, S; Markowitz, P; Martinez, G; Rodriguez, J L; Adams, J R; Adams, T; Askew, A; Bochenek, J; Diamond, B; Haas, J; Hagopian, S; Hagopian, V; Johnson, K F; Prosper, H; Veeraraghavan, V; Weinberg, M; Baarmand, M M; Hohlmann, M; Kalakhety, H; Yumiceva, F; Adams, M R; Apanasevich, L; Berry, D; Betts, R R; Bucinskaite, I; Cavanaugh, R; Evdokimov, O; Gauthier, L; Gerber, C E; Hofman, D J; Kurt, P; O'Brien, C; Sandoval Gonzalez, I D; Silkworth, C; Turner, P; Varelas, N; Bilki, B; Clarida, W; Dilsiz, K; Haytmyradov, M; Khristenko, V; Merlo, J-P; Mermerkaya, H; Mestvirishvili, A; Moeller, A; Nachtman, J; Ogul, H; Onel, Y; Ozok, F; Penzo, A; Rahmat, R; Sen, S; Tan, P; Tiras, E; Wetzel, J; Yi, K; Anderson, I; Barnett, B A; Blumenfeld, B; Bolognesi, S; Fehling, D; Gritsan, A V; Maksimovic, P; Martin, C; Swartz, M; Xiao, M; Baringer, P; Bean, A; Benelli, G; Bruner, C; Gray, J; Kenny, R P; Majumder, D; Malek, M; Murray, M; Noonan, D; Sanders, S; Sekaric, J; Stringer, R; Wang, Q; Wood, J S; Chakaberia, I; Ivanov, A; Kaadze, K; Khalil, S; Makouski, M; Maravin, Y; Saini, L K; Skhirtladze, N; Svintradze, I; Gronberg, J; Lange, D; Rebassoo, F; Wright, D; Anelli, C; Baden, A; Belloni, A; Calvert, B; Eno, S C; Gomez, J A; Hadley, N J; Jabeen, S; Kellogg, R G; Kolberg, T; Lu, Y; Mignerey, A C; Pedro, K; Shin, Y H; Skuja, A; Tonjes, M B; Tonwar, S C; Apyan, A; Barbieri, R; Bierwagen, K; Busza, W; Cali, I A; Di Matteo, L; Gomez Ceballos, G; Goncharov, M; Gulhan, D; Klute, M; Lai, Y S; Lee, Y-J; Levin, A; Luckey, P D; Paus, C; Ralph, D; Roland, C; Roland, G; Stephans, G S F; Sumorok, K; Velicanu, D; Veverka, J; Wyslouch, B; Yang, M; Zanetti, M; Zhukova, V; Dahmes, B; Gude, A; Kao, S C; Klapoetke, K; Kubota, Y; Mans, J; Nourbakhsh, S; Rusack, R; Singovsky, A; Tambe, N; Turkewitz, J; Acosta, J G; Oliveros, S; Avdeeva, E; Bloom, K; Bose, S; Claes, D R; Dominguez, A; Gonzalez Suarez, R; Keller, J; Knowlton, D; Kravchenko, I; Lazo-Flores, J; Meier, F; Ratnikov, F; Snow, G R; Zvada, M; Dolen, J; Godshalk, A; Iashvili, I; Kharchilava, A; Kumar, A; Rappoccio, S; Alverson, G; Barberis, E; Baumgartel, D; Chasco, M; Massironi, A; Morse, D M; Nash, D; Orimoto, T; Trocino, D; Wang, R-J; Wood, D; Zhang, J; Hahn, K A; Kubik, A; Mucia, N; Odell, N; Pollack, B; Pozdnyakov, A; Schmitt, M; Stoynev, S; Sung, K; Trovato, M; Velasco, M; Won, S; Brinkerhoff, A; Chan, K M; Drozdetskiy, A; Hildreth, M; Jessop, C; Karmgard, D J; Kellams, N; Lannon, K; Lynch, S; Marinelli, N; Musienko, Y; Pearson, T; Planer, M; Ruchti, R; Smith, G; Valls, N; Wayne, M; Wolf, M; Woodard, A; Antonelli, L; Brinson, J; Bylsma, B; Durkin, L S; Flowers, S; Hart, A; Hill, C; Hughes, R; Kotov, K; Ling, T Y; Luo, W; Puigh, D; Rodenburg, M; Winer, B L; Wolfe, H; Wulsin, H W; Driga, O; Elmer, P; Hardenbrook, J; Hebda, P; Koay, S A; Lujan, P; Marlow, D; Medvedeva, T; Mooney, M; Olsen, J; Piroué, P; Quan, X; Saka, H; Stickland, D; Tully, C; Werner, J S; Zuranski, A; Brownson, E; Malik, S; Mendez, H; Ramirez Vargas, J E; Barnes, V E; Benedetti, D; Bortoletto, D; Gutay, L; Hu, Z; Jha, M K; Jones, M; Jung, K; Kress, M; Leonardo, N; Miller, D H; Neumeister, N; Primavera, F; Radburn-Smith, B C; Shi, X; Shipsey, I; Silvers, D; Svyatkovskiy, A; Wang, F; Xie, W; Xu, L; Zablocki, J; Parashar, N; Stupak, J; Adair, A; Akgun, B; Ecklund, K M; Geurts, F J M; Li, W; Michlin, B; Padley, B P; Redjimi, R; Roberts, J; Zabel, J; Betchart, B; Bodek, A; de Barbaro, P; Demina, R; Eshaq, Y; Ferbel, T; Galanti, M; Garcia-Bellido, A; Goldenzweig, P; Han, J; Harel, A; Hindrichs, O; Khukhunaishvili, A; Korjenevski, S; Petrillo, G; Verzetti, M; Vishnevskiy, D; Ciesielski, R; Demortier, L; Goulianos, K; Mesropian, C; Arora, S; Barker, A; Chou, J P; Contreras-Campana, C; Contreras-Campana, E; Duggan, D; Ferencek, D; Gershtein, Y; Gray, R; Halkiadakis, E; Hidas, D; Hughes, E; Kaplan, S; Lath, A; Panwalkar, S; Park, M; Salur, S; Schnetzer, S; Sheffield, D; Somalwar, S; Stone, R; Thomas, S; Thomassen, P; Walker, M; Rose, K; Spanier, S; York, A; Bouhali, O; Castaneda Hernandez, A; Dalchenko, M; De Mattia, M; Dildick, S; Eusebi, R; Flanagan, W; Gilmore, J; Kamon, T; Khotilovich, V; Krutelyov, V; Montalvo, R; Osipenkov, I; Pakhotin, Y; Patel, R; Perloff, A; Roe, J; Rose, A; Safonov, A; Suarez, I; Tatarinov, A; Ulmer, K A; Akchurin, N; Cowden, C; Damgov, J; Dragoiu, C; Dudero, P R; Faulkner, J; Kovitanggoon, K; Kunori, S; Lee, S W; Libeiro, T; Volobouev, I; Appelt, E; Delannoy, A G; Greene, S; Gurrola, A; Johns, W; Maguire, C; Mao, Y; Melo, A; Sharma, M; Sheldon, P; Snook, B; Tuo, S; Velkovska, J; Arenton, M W; Boutle, S; Cox, B; Francis, B; Goodell, J; Hirosky, R; Ledovskoy, A; Li, H; Lin, C; Neu, C; Wolfe, E; Wood, J; Clarke, C; Harr, R; Karchin, P E; Kottachchi Kankanamge Don, C; Lamichhane, P; Sturdy, J; Belknap, D A; Carlsmith, D; Cepeda, M; Dasu, S; Dodd, L; Duric, S; Friis, E; Hall-Wilton, R; Herndon, M; Hervé, A; Klabbers, P; Lanaro, A; Lazaridis, C; Levine, A; Loveless, R; Mohapatra, A; Ojalvo, I; Perry, T; Pierro, G A; Polese, G; Ross, I; Sarangi, T; Savin, A; Smith, W H; Taylor, D; Vuosalo, C; Woods, N

2015-07-03

The second-order azimuthal anisotropy Fourier harmonics, v2, are obtained in p-Pb and PbPb collisions over a wide pseudorapidity (η) range based on correlations among six or more charged particles. The p-Pb data, corresponding to an integrated luminosity of 35  nb-1, were collected during the 2013 LHC p-Pb run at a nucleon-nucleon center-of-mass energy of 5.02  TeV by the CMS experiment. A sample of semiperipheral PbPb collision data at √sNN=2.76  TeV, corresponding to an integrated luminosity of 2.5  μb-1 and covering a similar range of particle multiplicities as the p-Pb data, is also analyzed for comparison. The six- and eight-particle cumulant and the Lee-Yang zeros methods are used to extract the v2 coefficients, extending previous studies of two- and four-particle correlations. For both the p-Pb and PbPb systems, the v2 values obtained with correlations among more than four particles are consistent with previously published four-particle results. These data support the interpretation of a collective origin for the previously observed long-range (large Δη) correlations in both systems. The ratios of v2 values corresponding to correlations including different numbers of particles are compared to theoretical predictions that assume a hydrodynamic behavior of a p-Pb system dominated by fluctuations in the positions of participant nucleons. These results provide new insights into the multiparticle dynamics of collision systems with a very small overlapping region.

Evidence for Collective Multiparticle Correlations in p-Pb Collisions

DOE PAGES

Khachatryan, Vardan

2015-06-29

The second-order azimuthal anisotropy Fourier harmonics, v 2, are obtained in p-Pb and PbPb collisions over a wide pseudorapidity (η) range based on correlations among six or more charged particles. The p-Pb data, corresponding to an integrated luminosity of 35 nb -1, were collected during the 2013 LHC p-Pb run at a nucleon-nucleon center-of-mass energy of 5.02 TeV by the CMS experiment. A sample of semiperipheral PbPb collision data at √ sNN=2.76 TeV, corresponding to an integrated luminosity of 2.5 μb -1 and covering a similar range of particle multiplicities as the p-Pb data, is also analyzed for comparison. Themore » six- and eight-particle cumulant and the Lee-Yang zeros methods are used to extract the v 2 coefficients, extending previous studies of two- and four-particle correlations. For both the p-Pb and PbPb systems, the v 2 values obtained with correlations among more than four particles are consistent with previously published four-particle results. These data support the interpretation of a collective origin for the previously observed long-range (large Δη) correlations in both systems. The ratios of v 2 values corresponding to correlations including different numbers of particles are compared to theoretical predictions that assume a hydrodynamic behavior of a p-Pb system dominated by fluctuations in the positions of participant nucleons. These results provide new insights into the multiparticle dynamics of collision systems with a very small overlapping region.« less

Precise correlation of histopathological and fluorescein angiographic morphology using retinal vascular casting.

PubMed

Bek, T; Prause, J U

1996-12-01

The histopathology of three eyes obtained post mortem from 2 patients with age-related macular degeneration was correlated with the pre mortem fluorescein angiographic morphology. A precise point-by-point correlation between histopathology and the corresponding angiographic appearance was ensured by using the cast retinal vascular system as a pattern of reference. The study showed that both the photoreceptors, the pigment epithelium, and substances accumulated between the retinal and the choroidal vascular systems, may have a blocking effect on choroidal background fluorescence as seen on fluorescein angiograms. Furthermore, it is confirmed that fluorescein angiographic hyperfluorescence may be due to a lack of blocking of the choroidal fluorescence because of a window defect in the retinal photoreceptor layer and/or the pigment epithelium.

Two-particle microrheology of quasi-2D viscous systems.

PubMed

Prasad, V; Koehler, S A; Weeks, Eric R

2006-10-27

We study the spatially correlated motions of colloidal particles in a quasi-2D system (human serum albumin protein molecules at an air-water interface) for different surface viscosities eta s. We observe a transition in the behavior of the correlated motion, from 2D interface dominated at high eta s to bulk fluid dependent at low eta s. The correlated motions can be scaled onto a master curve which captures the features of this transition. This master curve also characterizes the spatial dependence of the flow field of a viscous interface in response to a force. The scale factors used for the master curve allow for the calculation of the surface viscosity eta s that can be compared to one-particle measurements.

Medical informatics in medical research - the Severe Malaria in African Children (SMAC) Network's experience.

PubMed

Olola, C H O; Missinou, M A; Issifou, S; Anane-Sarpong, E; Abubakar, I; Gandi, J N; Chagomerana, M; Pinder, M; Agbenyega, T; Kremsner, P G; Newton, C R J C; Wypij, D; Taylor, T E

2006-01-01

Computers are widely used for data management in clinical trials in the developed countries, unlike in developing countries. Dependable systems are vital for data management, and medical decision making in clinical research. Monitoring and evaluation of data management is critical. In this paper we describe database structures and procedures of systems used to implement, coordinate, and sustain data management in Africa. We outline major lessons, challenges and successes achieved, and recommendations to improve medical informatics application in biomedical research in sub-Saharan Africa. A consortium of experienced research units at five sites in Africa in studying children with disease formed a new clinical trials network, Severe Malaria in African Children. In December 2000, the network introduced an observational study involving these hospital-based sites. After prototyping, relational database management systems were implemented for data entry and verification, data submission and quality assurance monitoring. Between 2000 and 2005, 25,858 patients were enrolled. Failure to meet data submission deadline and data entry errors correlated positively (correlation coefficient, r = 0.82), with more errors occurring when data was submitted late. Data submission lateness correlated inversely with hospital admissions (r = -0.62). Developing and sustaining dependable DBMS, ongoing modifications to optimize data management is crucial for clinical studies. Monitoring and communication systems are vital in multi-center networks for good data management. Data timeliness is associated with data quality and hospital admissions.

The efficacy of family reunification practices: reentry rates and correlates of reentry for abused and neglected children reunited with their families.

PubMed

Terling, T

1999-12-01

Since the 1980s Child Protective Services has increasingly relied on family reunification for abused/neglected children rather than long term foster care or adoption. While family reunification practices are controversial, little research is available to inform the debate. This research explores the efficacy of these practices. This study utilizes two CPS data sources and both quantitative and qualitative methodologies to identify reentry rates and correlates of reentry for abused and neglected children returned to their families by CPS. System reentry due to additional maltreatment is considerable. Thirty-seven percent of the children reunited with their families reenter the system within 3 1/2 years. Correlates of reentry are identified as; abuse type, CPS history, parental competency, race, criminal history, substance abuse, and social support. Notably, assessments of risk made by caseworkers are found to be unrelated to reentry. The high reentry rate and the limitations of current risk assessment procedures suggest that CPS family reunification practices have not been entirely successful. The identification of specific risks of reentry, such as those revealed in this study, will be helpful in assessing risk on cases. In addition, future studies should explore the systemic deficiencies that contribute to the additional maltreatment that occurs for a sizable proportion of the children served by the system.

Phase and vortex correlations in superconducting Josephson-junction arrays at irrational magnetic frustration.

PubMed

Granato, Enzo

2008-07-11

Phase coherence and vortex order in a Josephson-junction array at irrational frustration are studied by extensive Monte Carlo simulations using the parallel-tempering method. A scaling analysis of the correlation length of phase variables in the full equilibrated system shows that the critical temperature vanishes with a power-law divergent correlation length and critical exponent nuph, in agreement with recent results from resistivity scaling analysis. A similar scaling analysis for vortex variables reveals a different critical exponent nuv, suggesting that there are two distinct correlation lengths associated with a decoupled zero-temperature phase transition.

An alternative way to track the hot money in turbulent times

NASA Astrophysics Data System (ADS)

Sensoy, Ahmet

2015-02-01

During recent years, networks have proven to be an efficient way to characterize and investigate a wide range of complex financial systems. In this study, we first obtain the dynamic conditional correlations between filtered exchange rates (against US dollar) of several countries and introduce a time-varying threshold correlation level to define dynamic strong correlations between these exchange rates. Then, using evolving networks obtained from strong correlations, we propose an alternative approach to track the hot money in turbulent times. The approach is demonstrated for the time period including the financial turmoil of 2008. Other applications are also discussed.

Performance Analysis of Amplify-and-Forward Systems with Single Relay Selection in Correlated Environments

PubMed Central

Nguyen, Binh Van; Kim, Kiseon

2016-01-01

In this paper, we consider amplify-and-forward (AnF) cooperative systems under correlated fading environments. We first present a brief overview of existing works on the effect of channel correlations on the system performance. We then focus on our main contribution which is analyzing the outage probability of a multi-AnF-relay system with the best relay selection (BRS) scheme under a condition that two channels of each relay, source-relay and relay-destination channels, are correlated. Using lower and upper bounds on the end-to-end received signal-to-noise ratio (SNR) at the destination, we derive corresponding upper and lower bounds on the system outage probability. We prove that the system can achieve a diversity order (DO) equal to the number of relays. In addition, and importantly, we show that the considered correlation form has a constructive effect on the system performance. In other words, the larger the correlation coefficient, the better system performance. Our analytic results are corroborated by extensive Monte-Carlo simulations. PMID:27626426

Assessment of higher order correlation effects with the help of Moller-Plesset perturbation theory up to sixth order

NASA Astrophysics Data System (ADS)

He, Yuan; Cremer, Dieter

For 30 molecules and two atoms, MP n correlation energies up to n = 6 are computed and used to analyse higher order correlation effects and the initial convergence behaviour of the MP n series. Particularly useful is the analysis of correlation contributions E(n)XY ...( n = 4,5,6; X , Y ,... = S, D, T, Q denoting single, double, triple, and quadruple excitations) in the form of correlation energy spectra. Two classes of system are distinguished, namely class A systems possessing well separated electron pairs and class B systems which are characterized by electron clustering in certain regions of atomic and molecular space. For class A systems, electron pair correlation effects as described by D, Q, DD, DQ, QQ, DDD, etc., contributions are most important, which are stepwise included at MP n with n = 2,... ,6. Class A systems are reasonably described by MP n theory, which is reflected by the fact that convergence of the MP n series is monotonic (but relatively slow) for class A systems. The description of class B systems is difficult since three- and four-electron correlation effects and couplings between two-, three-, and four-electron correlation effects missing for lower order perturbation theory are significant. MP n methods, which do not cover these effects, simulate higher order with lower order correlation effects thus exaggerating the latter, which has to be corrected with increasing n. Consequently, the MP n series oscillates for class B systems at low orders. A possible divergence of the MP n series is mostly a consequence of an unbalanced basis set. For example, diffuse functions added to an unsaturated sp basis lead to an exaggeration of higher order correlation effects, which can cause enhanced oscillations and divergence of the MP n series.

Correlation of the clinical and physical image quality in chest radiography for average adults with a computed radiography imaging system.

PubMed

Moore, C S; Wood, T J; Beavis, A W; Saunderson, J R

2013-07-01

The purpose of this study was to examine the correlation between the quality of visually graded patient (clinical) chest images and a quantitative assessment of chest phantom (physical) images acquired with a computed radiography (CR) imaging system. The results of a previously published study, in which four experienced image evaluators graded computer-simulated postero-anterior chest images using a visual grading analysis scoring (VGAS) scheme, were used for the clinical image quality measurement. Contrast-to-noise ratio (CNR) and effective dose efficiency (eDE) were used as physical image quality metrics measured in a uniform chest phantom. Although optimal values of these physical metrics for chest radiography were not derived in this work, their correlation with VGAS in images acquired without an antiscatter grid across the diagnostic range of X-ray tube voltages was determined using Pearson's correlation coefficient. Clinical and physical image quality metrics increased with decreasing tube voltage. Statistically significant correlations between VGAS and CNR (R=0.87, p<0.033) and eDE (R=0.77, p<0.008) were observed. Medical physics experts may use the physical image quality metrics described here in quality assurance programmes and optimisation studies with a degree of confidence that they reflect the clinical image quality in chest CR images acquired without an antiscatter grid. A statistically significant correlation has been found between the clinical and physical image quality in CR chest imaging. The results support the value of using CNR and eDE in the evaluation of quality in clinical thorax radiography.

Evolution of pressures and correlations in the glasma produced in high energy nuclear collisions

NASA Astrophysics Data System (ADS)

Ruggieri, M.; Liu, J. H.; Oliva, L.; Peng, G. X.; Greco, V.

2018-04-01

We consider the SU(2) glasma with Gaussian fluctuations and study its evolution by means of classical Yang-Mills equations solved numerically on a lattice. Neglecting in this first study the longitudinal expansion, we follow the evolution of the pressures of the system and compute the effect of the fluctuations in the early stage up to t ≈2 fm /c , that is the time range in which the glasma is relevant for high energy collisions. We measure the ratio of the longitudinal over the transverse pressure, PL/PT, and we find that unless the fluctuations carry a substantial amount of the energy density at the initial time, they do not change significantly the evolution of PL/PT in the early stage and that the system remains quite anisotropic. We also measure the longitudinal fields correlators both in the transverse plane and along the longitudinal direction: while at initial time fields appear to be anticorrelated in the transverse plane, this anticorrelation disappears in the very early stage, and the correlation length in the transverse plane increases. On the other hand, we find a dependence of the gauge invariant correlator on the longitudinal coordinate, which we interpret as a partial loss of correlation induced by the dynamics that we dub the gauge invariant string breaking. We finally study the effect of fluctuations on the longitudinal correlations: we find that string breaking is accelerated by the fluctuations and waiting for a sufficiently long time fluctuations lead to the complete breaking of the color strings.

Correlation of resting and exercising endoscopic findings for horses with dynamic laryngeal collapse and palatal dysfunction.

PubMed

Barakzai, S Z; Dixon, P M

2011-01-01

To correlate resting and exercising endoscopic grades of laryngeal function in horses undergoing high-speed treadmill endoscopy (HSTE) using the Havemeyer grading system. To correlate dorsal displacement of the soft palate (DDSP) seen at rest with palatal function during exercise. Records of horses that underwent HSTE examination (1999-2009) were reviewed. Resting laryngeal function score and other abnormalities noted on resting endoscopy were recorded as were results of HSTE. Results of resting and exercising endoscopic findings were correlated. 281 horses underwent HSTE. There was significant correlation between grade of laryngeal function at rest (grades 1-4) and exercise (ρ=0.53, P<0.001) and between resting subgrades 3.1, 3.2 and 3.3 and exercising grades of laryngeal function (ρ=0.43, P=0.0017). DDSP was observed at rest significantly more often in horses that developed DDSP during HSTE than those without DDSP during HSTE (RR=4.1, P<0.001). The sensitivity and specificity of DDSP seen during resting endoscopy as a test for DDSP occurring during exercise were 25.5 and 95.1% respectively (positive predictive value 0.57, negative predictive value 0.83). The results of the current study support the use of the Havemeyer system for grading laryngeal function in the resting horse, and corroborate findings of previous studies correlating resting and exercising palatal abnormalities. Studies that use the presence of spontaneous DDSP during resting endoscopic examination as an inclusion criterion for investigating efficacy of treatments for DDSP are likely to have a low proportion of horses with false positive diagnoses. © 2010 EVJ Ltd.

Performance evaluation of receive-diversity free-space optical communications over correlated Gamma-Gamma fading channels.

PubMed

Yang, Guowei; Khalighi, Mohammad-Ali; Ghassemlooy, Zabih; Bourennane, Salah

2013-08-20

The efficacy of spatial diversity in practical free-space optical communication systems is impaired by the fading correlation among the underlying subchannels. We consider in this paper the generation of correlated Gamma-Gamma random variables in view of evaluating the system outage probability and bit-error-rate under the condition of correlated fading. Considering the case of receive-diversity systems with intensity modulation and direct detection, we propose a set of criteria for setting the correlation coefficients on the small- and large-scale fading components based on scintillation theory. We verify these criteria using wave-optics simulations and further show through Monte Carlo simulations that we can effectively neglect the correlation corresponding to the small-scale turbulence in most practical systems, irrespective of the specific turbulence conditions. This has not been clarified before, to the best of our knowledge. We then present some numerical results to illustrate the effect of fading correlation on the system performance. Our conclusions can be generalized to the cases of multiple-beam and multiple-beam multiple-aperture systems.

Correspondence of electroencephalography and near-infrared spectroscopy sensitivities to the cerebral cortex using a high-density layout

PubMed Central

Giacometti, Paolo; Diamond, Solomon G.

2014-01-01

Abstract. This study investigates the correspondence of the cortical sensitivity of electroencephalography (EEG) and near-infrared spectroscopy (NIRS). EEG forward model sensitivity to the cerebral cortex was calculated for 329 EEG electrodes following the 10-5 EEG positioning system using a segmented structural magnetic resonance imaging scan of a human subject. NIRS forward model sensitivity was calculated for the same subject using 156 NIRS source-detector pairs selected from 32 source and 32 detector optodes positioned on the scalp using a subset of the 10-5 EEG positioning system. Sensitivity correlations between colocalized NIRS source-detector pair groups and EEG channels yielded R=0.46±0.08. Groups of NIRS source-detector pairs with maximum correlations to EEG electrode sensitivities are tabulated. The mean correlation between the point spread functions for EEG and NIRS regions of interest (ROI) was R=0.43±0.07. Spherical ROIs with radii of 26 mm yielded the maximum correlation between EEG and NIRS averaged across all cortical mesh nodes. These sensitivity correlations between EEG and NIRS should be taken into account when designing multimodal studies of neurovascular coupling and when using NIRS as a statistical prior for EEG source localization. PMID:25558462

Pressure effects on the electronic properties in CeCoIn5: A first-principle study

NASA Astrophysics Data System (ADS)

Medeiros, Gustavo; Gonzalez, J. L.; Scopel, Wanderlã L.

2017-11-01

Superconducting heavy fermions are exotic materials with strong electronic correlations. The temperature-pressure phase diagrams of some of these materials show a complex interplay between superconductivity and magnetism that is essential to understand the physical properties of these systems. In this work, first principle calculations are performed in order to study the pressure effects on the electronic correlations in the CeCoIn5 system, which is superconducting at ambient pressure with Tc = 2.3 K. The density functional theory (DFT) method was used to include on-site coulomb repulsions (U) at the d (Co and In) and f (Ce) electrons of the CeCoIn5 compound. External applied pressures were simulated by correlating an applied pressure with a reduction of the volume of the unit cell, but keeping constant the c/a relation, as reported in experiments. Our findings reveal that the U parameters for all atomic species increase linearly with the pressure (P), being this effect higher for the f-electrons of the cerium ions, where dU / dP = 1.2 eV/GPa. In summary, these results not only suggest that the pressure effect can be correlated with an increase in the electronic correlations in the CeCoIn5 compound, as also, the work allows quantify this effect.

Multicenter study of quantitative computed tomography analysis using a computer-aided three-dimensional system in patients with idiopathic pulmonary fibrosis.

PubMed

Iwasawa, Tae; Kanauchi, Tetsu; Hoshi, Toshiko; Ogura, Takashi; Baba, Tomohisa; Gotoh, Toshiyuki; Oba, Mari S

2016-01-01

To evaluate the feasibility of automated quantitative analysis with a three-dimensional (3D) computer-aided system (i.e., Gaussian histogram normalized correlation, GHNC) of computed tomography (CT) images from different scanners. Each institution's review board approved the research protocol. Informed patient consent was not required. The participants in this multicenter prospective study were 80 patients (65 men, 15 women) with idiopathic pulmonary fibrosis. Their mean age was 70.6 years. Computed tomography (CT) images were obtained by four different scanners set at different exposures. We measured the extent of fibrosis using GHNC, and used Pearson's correlation analysis, Bland-Altman plots, and kappa analysis to directly compare the GHNC results with manual scoring by radiologists. Multiple linear regression analysis was performed to determine the association between the CT data and forced vital capacity (FVC). For each scanner, the extent of fibrosis as determined by GHNC was significantly correlated with the radiologists' score. In multivariate analysis, the extent of fibrosis as determined by GHNC was significantly correlated with FVC (p < 0.001). There was no significant difference between the results obtained using different CT scanners. Gaussian histogram normalized correlation was feasible, irrespective of the type of CT scanner used.

Quantum correlation of high dimensional system in a dephasing environment

NASA Astrophysics Data System (ADS)

Ji, Yinghua; Ke, Qiang; Hu, Juju

2018-05-01

For a high dimensional spin-S system embedded in a dephasing environment, we theoretically analyze the time evolutions of quantum correlation and entanglement via Frobenius norm and negativity. The quantum correlation dynamics can be considered as a function of the decoherence parameters, including the ratio between the system oscillator frequency ω0 and the reservoir cutoff frequency ωc , and the different environment temperature. It is shown that the quantum correlation can not only measure nonclassical correlation of the considered system, but also perform a better robustness against the dissipation. In addition, the decoherence presents the non-Markovian features and the quantum correlation freeze phenomenon. The former is much weaker than that in the sub-Ohmic or Ohmic thermal reservoir environment.

Evaluation of liver function using gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid enhanced magnetic resonance imaging based on a three-dimensional volumetric analysis system.

PubMed

Kudo, Masashi; Gotohda, Naoto; Sugimoto, Motokazu; Kobayashi, Tatsushi; Kojima, Motohiro; Takahashi, Shinichiro; Konishi, Masaru; Hayashi, Ryuichi

2018-06-02

Magnetic resonance imaging with gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (EOB-MRI) is a diagnostic modality for liver tumors. Three-dimensional (3D) volumetric analysis systems using EOB-MRI data are used to simulate liver anatomy for surgery. This study was conducted to investigate clinical utility of a 3D volumetric analysis system on EOB-MRI to evaluate liver function. Between August 2014 and December 2015, 181 patients underwent laboratory and radiological exams as standardized preoperative evaluation for liver surgery. The liver-spleen contrast-enhanced ratio (LSR) was measured by a semi-automated 3D volumetric analysis system on EOB-MRI. First, the inter-evaluator variability of the calculated LSR was evaluated. Additionally, a subset of liver surgical specimens was evaluated histologically by using immunohistochemical staining. Finally, the correlations between the LSR and grading systems of liver function, laboratory data, or histological findings were analyzed. The inter-evaluator correlation coefficient of the measured LSR was 0.986. The mean LSR was significantly correlated with the Child-Pugh score (p = 0.014) and the ALBI score (p < 0.001). Significant correlations were also observed between the LSR and indocyanine green retention rate at 15 min (r = - 0.601, p < 0.001), between the LSR and liver fibrosis stage (r = - 0.556, p < 0.001), and between the LSR and liver steatosis grade (r = - 0.396, p < 0.001). The LSR calculated by a 3D volumetric analysis system on EOB-MRI was highly reproducible and was shown to be correlated with liver function parameters and liver histology. These data suggest that this imaging modality can be a reliable tool to evaluate liver function.

An Examination of the Demographic and Environmental Variables Correlated with Lyme Disease Emergence in Virginia.

PubMed

Seukep, Sara E; Kolivras, Korine N; Hong, Yili; Li, Jie; Prisley, Stephen P; Campbell, James B; Gaines, David N; Dymond, Randel L

2015-12-01

Lyme disease is the United States' most significant vector-borne illness. Virginia, on the southern edge of the disease's currently expanding range, has experienced an increase in Lyme disease both spatially and temporally, with steadily increasing rates over the past decade and disease spread from the northern to the southwestern part of the state. This study used a Geographic Information System and a spatial Poisson regression model to examine correlations between demographic and land cover variables, and human Lyme disease from 2006 to 2010 in Virginia. Analysis indicated that herbaceous land cover is positively correlated with Lyme disease incidence rates. Areas with greater interspersion between herbaceous and forested land were also positively correlated with incidence rates. In addition, income and age were positively correlated with incidence rates. Levels of development, interspersion of herbaceous and developed land, and population density were negatively correlated with incidence rates. Abundance of forest fragments less than 2 hectares in area was not significantly correlated. Our results support some findings of previous studies on ecological variables and Lyme disease in endemic areas, but other results have not been found in previous studies, highlighting the potential contribution of new variables as Lyme disease continues to emerge southward.

Assessing agro-environmental performance of dairy farms in northwest Italy based on aggregated results from indicators.

PubMed

Gaudino, Stefano; Goia, Irene; Grignani, Carlo; Monaco, Stefano; Sacco, Dario

2014-07-01

Dairy farms control an important share of the agricultural area of Northern Italy. Zero grazing, large maize-cropped areas, high stocking densities, and high milk production make them intensive and prone to impact the environment. Currently, few published studies have proposed indicator sets able to describe the entire dairy farm system and their internal components. This work had four aims: i) to propose a list of agro-environmental indicators to assess dairy farms; ii) to understand which indicators classify farms best; iii) to evaluate the dairy farms based on the proposed indicator list; iv) to link farmer decisions to the consequent environmental pressures. Forty agro-environmental indicators selected for this study are described. Northern Italy dairy systems were analysed considering both farmer decision indicators (farm management) and the resulting pressure indicators that demonstrate environmental stress on the entire farming system, and its components: cropping system, livestock system, and milk production. The correlations among single indicators identified redundant indicators. Principal Components Analysis distinguished which indicators provided meaningful information about each pressure indicator group. Analysis of the communalities and the correlations among indicators identified those that best represented farm variability: Farm Gate N Balance, Greenhouse Gas Emission, and Net Energy of the farm system; Net Energy and Gross P Balance of the cropping system component; Energy Use Efficiency and Purchased Feed N Input of the livestock system component; N Eco-Efficiency of the milk production component. Farm evaluation, based on the complete list of selected indicators demonstrated organic farming resulted in uniformly high values, while farms with low milk-producing herds resulted in uniformly low values. Yet on other farms, the environmental quality varied greatly when different groups of pressure indicators were considered, which highlighted the importance of expanding environmental analysis to effects within the farm. Statistical analysis demonstrated positive correlations between all farmer decision and pressure group indicators. Consumption of mineral fertiliser and pesticide negatively influenced the cropping system. Furthermore, stocking rate was found to correlate positively with the milk production component and negatively with the farm system. This study provides baseline references for ex ante policy evaluation, and monitoring tools for analysis both in itinere and ex post environment policy implementation. Copyright © 2014 Elsevier Ltd. All rights reserved.

A Study of the Construct Validity of the Interactive Computer Interview System (ICIS) Using Student Evaluations as the Outcome Measure

ERIC Educational Resources Information Center

Gardner, Robby Christopher

2009-01-01

The primary objective of this study was to compare the individual teacher interview scores from the Interactive Computer Interview System (ICIS) with their students' responses to "The Steps to Excellence Student Questionnaire". Specifically, the study examined the correlation among the teacher interviews across four themes of the ICIS ("Knowledge…

Noisy Spins and the Richardson-Gaudin Model

NASA Astrophysics Data System (ADS)

Rowlands, Daniel A.; Lamacraft, Austen

2018-03-01

We study a system of spins (qubits) coupled to a common noisy environment, each precessing at its own frequency. The correlated noise experienced by the spins implies long-lived correlations that relax only due to the differing frequencies. We use a mapping to a non-Hermitian integrable Richardson-Gaudin model to find the exact spectrum of the quantum master equation in the high-temperature limit and, hence, determine the decay rate. Our solution can be used to evaluate the effect of inhomogeneous splittings on a system of qubits coupled to a common bath.

The correlation between brain gray matter volume and empathizing and systemizing quotients in healthy children.

PubMed

Sassa, Yuko; Taki, Yasuyuki; Takeuchi, Hikaru; Hashizume, Hiroshi; Asano, Michiko; Asano, Kohei; Wakabayashi, Akio; Kawashima, Ryuta

2012-05-01

The abilities to empathize and to systemize, two fundamental dimensions of cognitive style, are characterized by apparent individual differences. These abilities are typically measured using an empathizing quotient (EQ) and a systemizing quotient (SQ) questionnaire, respectively. The purpose of this study was to reveal any correlations between EQ and SQ scores and regional gray matter volumes in healthy children by applying voxel-based morphometry to magnetic resonance images. We collected MRIs of brain structure and administered children's versions of the EQ and SQ questionnaires (EQ-C and SQ-C, respectively) to 261 healthy children aged 5-15 years. Structural MRI data were segmented, normalized, and smoothed using an optimized voxel-based morphometric analysis. Next, we analyzed the correlation between regional gray matter volume and EQ-C and SQ-C scores adjusting for age, sex, and intracranial volume. The EQ-C scores showed significant positive correlations with the regional gray matter volumes of the left fronto-opercular and superior temporal cortices, including the precentral gyrus, the inferior frontal gyrus, the superior temporal gyrus, and the insula, which are functionally related to empathic processing. Additionally, SQ-C scores showed a significant negative correlation with the regional gray matter volume of the left posterior parietal cortex, which is functionally involved in selective attention processing. Our findings suggest that individual differences in cognitive style pertaining to empathizing or systemizing abilities could be explained by differences in the volume of brain structures that are functionally relevant to empathizing and systemizing. Copyright © 2012 Elsevier Inc. All rights reserved.

Epilepsy-related stigma in European people with epilepsy: correlations with health system performance and overall quality of life.

PubMed

Brigo, Francesco; Igwe, Stanley C; Ausserer, Harald; Tezzon, Frediano; Nardone, Raffaele; Otte, Willem M

2015-01-01

We aimed to relate the percentages of encountered epilepsy-related stigma in people with epilepsy with quantitative indicators of the quality of health systems and quality of life by country in Europe. The epilepsy-related stigma percentages were obtained from the largest population-based study in people with epilepsy available. We correlated percentages of people with perceived stigma per European country with data on the country's overall health system performance, health expenditure per capita in international dollars, and the Economist Intelligence Unit's quality-of-life index. We found a nonsignificant trend towards negative correlation between the epilepsy-related stigma percentage and the overall health system performance (r=-0.16; p=0.57), the health expenditure per capita in international dollars (r=-0.24; p=0.4), and the Economist Intelligence Unit's quality-of-life index (r=-0.33; p=0.91). Living in a European country with a better health system performance and higher health expenditure per capita does not necessarily lead to a reduction in perceived epilepsy-related discrimination, unless the public health system invests on awareness programs to increase public knowledge and reduce stigma. Copyright © 2014 Elsevier Inc. All rights reserved.

Wireless wearable range-of-motion sensor system for upper and lower extremity joints: a validation study.

PubMed

Kumar, Yogaprakash; Yen, Shih-Cheng; Tay, Arthur; Lee, Wangwei; Gao, Fan; Zhao, Ziyi; Li, Jingze; Hon, Benjamin; Tian-Ma Xu, Tim; Cheong, Angela; Koh, Karen; Ng, Yee-Sien; Chew, Effie; Koh, Gerald

2015-02-01

Range-of-motion (ROM) assessment is a critical assessment tool during the rehabilitation process. The conventional approach uses the goniometer which remains the most reliable instrument but it is usually time-consuming and subject to both intra- and inter-therapist measurement errors. An automated wireless wearable sensor system for the measurement of ROM has previously been developed by the current authors. Presented is the correlation and accuracy of the automated wireless wearable sensor system against a goniometer in measuring ROM in the major joints of upper (UEs) and lower extremities (LEs) in 19 healthy subjects and 20 newly disabled inpatients through intra (same) subject comparison of ROM assessments between the sensor system against goniometer measurements by physical therapists. In healthy subjects, ROM measurements using the new sensor system were highly correlated with goniometry, with 95% of differences < 20° and 10° for most movements in major joints of UE and LE, respectively. Among inpatients undergoing rehabilitation, ROM measurements using the new sensor system were also highly correlated with goniometry, with 95% of the differences being < 20° and 25° for most movements in the major joints of UE and LE, respectively.

Parametric number covariance in quantum chaotic spectra.

PubMed

Vinayak; Kumar, Sandeep; Pandey, Akhilesh

2016-03-01

We study spectral parametric correlations in quantum chaotic systems and introduce the number covariance as a measure of such correlations. We derive analytic results for the classical random matrix ensembles using the binary correlation method and obtain compact expressions for the covariance. We illustrate the universality of this measure by presenting the spectral analysis of the quantum kicked rotors for the time-reversal invariant and time-reversal noninvariant cases. A local version of the parametric number variance introduced earlier is also investigated.

Measuring the executive regulation of emotion with self-rating scales in a nonclinical population.

PubMed

Spinella, Marcello

2007-01-01

Prefrontal systems play an important role in the regulation of emotion as evidenced by clinical neuroimaging studies. Both subjective and objective neuropsychological tests provide functional evidence of executive dysfunction in emotional deregulation. The present authors evaluated these relationships here in a nonclinical community sample using the Frontal Systems Behavior Scale, Profile of Mood States (POMS), and Depression Anxiety Stress Scales (DASS). Positive correlations uniformly emerged between prefrontal system dysfunction and negative emotional states (anger, depression, anxiety, stress, confusion, and fatigue), whereas positive emotion (vigor) showed a modest inverse correlation with prefrontal system dysfunction, even after control for demographic influences. These relationships may result from cognitive strategies for managing emotion mediated by reciprocal connections between prefrontal systems and the limbic system. The findings corroborated those of other methodologies, supporting the Frontal Systems Behavior Scale (FrSBe) as a valid tool to measure prefrontal function in nonclinical populations.

Self-Organized Lattices of Nonlinear Optochemical Waves in Photopolymerizable Fluids: The Spontaneous Emergence of 3-D Order in a Weakly Correlated System.

PubMed

Ponte, Matthew R; Hudson, Alexander D; Saravanamuttu, Kalaichelvi

2018-03-01

Many of the extraordinary three-dimensional architectures that pattern our physical world emerge from complex nonlinear systems or dynamic populations whose individual constituents are only weakly correlated to each other. Shoals of fish, murmuration behaviors in birds, congestion patterns in traffic, and even networks of social conventions are examples of spontaneous pattern formation, which cannot be predicted from the properties of individual elements alone. Pattern formation at a different scale has been observed or predicted in weakly correlated systems including superconductors, atomic gases near Bose Einstein condensation, and incoherent optical fields. Understanding pattern formation in nonlinear weakly correlated systems, which are often unified through mathematical expression, could pave intelligent self-organizing pathways to functional materials, architectures, and computing technologies. However, it is experimentally difficult to directly visualize the nonlinear dynamics of pattern formation in most populations-especially in three dimensions. Here, we describe the collective behavior of large populations of nonlinear optochemical waves, which are poorly correlated in both space and time. The optochemical waves-microscopic filaments of white light entrapped within polymer channels-originate from the modulation instability of incandescent light traveling in photopolymerizable fluids. By tracing the three-dimensional distribution of optical intensity in the nascent polymerizing system, we find that populations of randomly distributed, optochemical waves synergistically and collectively shift in space to form highly ordered lattices of specific symmetries. These, to our knowledge, are the first three-dimensionally periodic structures to emerge from a system of weakly correlated waves. Their spontaneous formation in an incoherent and effectively chaotic field is counterintuitive, but the apparent contradiction of known behaviors of light including the laws of optical interference can be explained through the soliton-like interactions of optochemical waves with nearest neighbors. Critically, this work casts fundamentally new insight into the collective behaviors of poorly correlated nonlinear waves in higher dimensions and provides a rare, accessible platform for further experimental studies of these previously unexplored behaviors. Furthermore, it defines a self-organization paradigm that, unlike conventional counterparts, could generate polymer microstructures with symmetries spanning all the Bravais lattices.

Petascale Many Body Methods for Complex Correlated Systems

NASA Astrophysics Data System (ADS)

Pruschke, Thomas

2012-02-01

Correlated systems constitute an important class of materials in modern condensed matter physics. Correlation among electrons are at the heart of all ordering phenomena and many intriguing novel aspects, such as quantum phase transitions or topological insulators, observed in a variety of compounds. Yet, theoretically describing these phenomena is still a formidable task, even if one restricts the models used to the smallest possible set of degrees of freedom. Here, modern computer architectures play an essential role, and the joint effort to devise efficient algorithms and implement them on state-of-the art hardware has become an extremely active field in condensed-matter research. To tackle this task single-handed is quite obviously not possible. The NSF-OISE funded PIRE collaboration ``Graduate Education and Research in Petascale Many Body Methods for Complex Correlated Systems'' is a successful initiative to bring together leading experts around the world to form a virtual international organization for addressing these emerging challenges and educate the next generation of computational condensed matter physicists. The collaboration includes research groups developing novel theoretical tools to reliably and systematically study correlated solids, experts in efficient computational algorithms needed to solve the emerging equations, and those able to use modern heterogeneous computer architectures to make then working tools for the growing community.

Comparison Of Pre-Operative Curvature With Postoperative Curvature In Root Canals Treated With K-3 Rotary Systems.

PubMed

Nagi, Sana Ehsen; Khan, Farhan Raza

2017-01-01

With root canal treatment, the organic debris and micro-organisms from pulp space is removed and an ideal canal preparation is achieved that is conducive of hermetic obturation. The purpose of this study was to correlate the pre-operative canal curvature with the postoperative curvature in human extracted teeth prepared with K-3 rotary systems. The root canal preparation was carried out on extracted human molars and premolars using K-3 endodontic rotary files. A pre and post-operative image of the teeth using digital radiograph were taken in order to compare pre and post-operative canal curvature. The images were saved in an images retrieval system (Gendex software, USA). Change in the canal curvature was measured using the software measuring tool (Vixwin software, USA). Student paired t-test and Pearson correlation test was applied at 0.05 level of significance. There is a statistically significant difference between pre-operative and post-operative canal curvature (p-value <0.001) and a strong positive correlation (91% correlation) between pre-operative and post-operative canal curvature in teeth prepared with the K-3 rotary files. A significant difference between pre and post instrumentation curvature was found. Degree of canal curvature was not correlated with time taken for canal preparation.

Interactions between serum leptin, the insulin-like growth factor-I system, and sex, age, anthropometric and body composition variables in a healthy population randomly selected.

PubMed

Gómez, José Manuel; Maravall, Francisco Javier; Gómez, Núria; Navarro, Miguel Angel; Casamitjana, Roser; Soler, Juan

2003-02-01

Leptin secretion is influenced by many factors and the GH/IGF axis plays an important role in the regulation of body composition, but the physiological interactions between leptin and the IGF-I system remain unknown. In this study we investigated the relationship between leptin, the IGF-I system, and sex, age, anthropometric and body composition variables in a group of healthy adults randomly selected. A cross-sectional study. The study included 268 subjects, representative of the whole population of the city of L'Hospitalet de Llobregat in sex and age distribution: 134 men aged 41.4 years, range 15-70 years; and 134 women, aged 40.7 years, range 15-70 years. Body mass index (BMI) was calculated, and body composition was determined by using a bioelectrical impedance analyser. Serum leptin concentrations were determined by using a radioimmunoassay (RIA). Serum total IGF-I concentrations, after acid-ethanol extraction, were also measured by RIA. Serum free IGF-I concentrations were determined by an enzymoimmunometric assay. Serum IGFBP3 concentrations were determined by RIA. Plasma basal TSH concentrations were determined by a specific electrochemiluminescence assay. In men the BMI was similar in all decades and waist/hip ratio increased in the last three decades. Fat-free mass decreased by decade. We observed an increase in leptin in the fourth decade with a decrease in IGF-I, free IGF-I and IGFBP3 throughout the decades. Basal TSH showed an increase in the last two decades. In women, BMI, waist/hip ratio and fat mass increased significantly in the last decades. Leptin concentrations increased in the last decades and total IGF-I, free IGF-I and IGFBP3 decreased by decade without changes in basal TSH concentration. In men, there was a positive correlation between leptin and BMI, waist/hip ratio, total body water, fat-free mass and fat mass, and these anthropometric and body composition variables showed a negative correlation with free IGF-I and IGFBP3, without any correlation with total IGF-I. In women, there was a positive correlation between leptin and BMI, waist/hip ratio, total body water, fat-free mass, and fat mass, which showed a negative correlation with total IGF-I and IGFBP3, without any correlation with free IGF-I. In men, total IGF-I was negatively correlated with waist/hip ratio without any correlation with the other variables and free IGF-I was negatively correlated with BMI and waist/hip ratio, and IGFBP3 did not show any correlation. In women, total IGF-I, free IGF-I and IGFBP3 were negatively correlated with BMI, waist/hip ratio and fat mass. The multiple linear regression analysis produced a model that explained 60.5% of leptin variability in men and 40% in women. Notably, only age, BMI, fat mass and waist/hip ratio brought an independent significant contribution to leptin variability. The final model also explained 28.2% and 60.4% of total IGF-I variability and 17.2% and 27.4% of free IGF-I variability in men and women, respectively. Age and leptin contributed to free IGF-I variability in men, and age and fat mass were significantly and independently associated with total IGF-I in women. In this well-characterized population of controls randomly selected without chronic disease or drug administration and with biochemically confirmed euthyroidism, we found that both men and women had a significant correlation between leptin levels and the IGF-I system, and anthropometric and body composition variables, but that leptin did not regulate the IGF-I system, and that the IGF-I system did not regulate leptin synthesis and secretion.

A New Methodology of Spatial Cross-Correlation Analysis

PubMed Central

Chen, Yanguang

2015-01-01

Spatial correlation modeling comprises both spatial autocorrelation and spatial cross-correlation processes. The spatial autocorrelation theory has been well-developed. It is necessary to advance the method of spatial cross-correlation analysis to supplement the autocorrelation analysis. This paper presents a set of models and analytical procedures for spatial cross-correlation analysis. By analogy with Moran’s index newly expressed in a spatial quadratic form, a theoretical framework is derived for geographical cross-correlation modeling. First, two sets of spatial cross-correlation coefficients are defined, including a global spatial cross-correlation coefficient and local spatial cross-correlation coefficients. Second, a pair of scatterplots of spatial cross-correlation is proposed, and the plots can be used to visually reveal the causality behind spatial systems. Based on the global cross-correlation coefficient, Pearson’s correlation coefficient can be decomposed into two parts: direct correlation (partial correlation) and indirect correlation (spatial cross-correlation). As an example, the methodology is applied to the relationships between China’s urbanization and economic development to illustrate how to model spatial cross-correlation phenomena. This study is an introduction to developing the theory of spatial cross-correlation, and future geographical spatial analysis might benefit from these models and indexes. PMID:25993120

A new methodology of spatial cross-correlation analysis.

PubMed

Chen, Yanguang

2015-01-01

Spatial correlation modeling comprises both spatial autocorrelation and spatial cross-correlation processes. The spatial autocorrelation theory has been well-developed. It is necessary to advance the method of spatial cross-correlation analysis to supplement the autocorrelation analysis. This paper presents a set of models and analytical procedures for spatial cross-correlation analysis. By analogy with Moran's index newly expressed in a spatial quadratic form, a theoretical framework is derived for geographical cross-correlation modeling. First, two sets of spatial cross-correlation coefficients are defined, including a global spatial cross-correlation coefficient and local spatial cross-correlation coefficients. Second, a pair of scatterplots of spatial cross-correlation is proposed, and the plots can be used to visually reveal the causality behind spatial systems. Based on the global cross-correlation coefficient, Pearson's correlation coefficient can be decomposed into two parts: direct correlation (partial correlation) and indirect correlation (spatial cross-correlation). As an example, the methodology is applied to the relationships between China's urbanization and economic development to illustrate how to model spatial cross-correlation phenomena. This study is an introduction to developing the theory of spatial cross-correlation, and future geographical spatial analysis might benefit from these models and indexes.

Detecting Pairwise Correlations in Spike Trains: An Objective Comparison of Methods and Application to the Study of Retinal Waves

PubMed Central

Eglen, Stephen J.

2014-01-01

Correlations in neuronal spike times are thought to be key to processing in many neural systems. Many measures have been proposed to summarize these correlations and of these the correlation index is widely used and is the standard in studies of spontaneous retinal activity. We show that this measure has two undesirable properties: it is unbounded above and confounded by firing rate. We list properties needed for a measure to fairly quantify and compare correlations and we propose a novel measure of correlation—the spike time tiling coefficient. This coefficient, the correlation index, and 33 other measures of correlation of spike times are blindly tested for the required properties on synthetic and experimental data. Based on this, we propose a measure (the spike time tiling coefficient) to replace the correlation index. To demonstrate the benefits of this measure, we reanalyze data from seven key studies, which previously used the correlation index to investigate the nature of spontaneous activity. We reanalyze data from β2(KO) and β2(TG) mutants, mutants lacking connexin isoforms, and also the age-dependent changes in wild-type and β2(KO) correlations. Reanalysis of the data using the proposed measure can significantly change the conclusions. It leads to better quantification of correlations and therefore better inference from the data. We hope that the proposed measure will have wide applications, and will help clarify the role of activity in retinotopic map formation. PMID:25339742

Magnitude and sign of long-range correlated time series: Decomposition and surrogate signal generation.

PubMed

Gómez-Extremera, Manuel; Carpena, Pedro; Ivanov, Plamen Ch; Bernaola-Galván, Pedro A

2016-04-01

We systematically study the scaling properties of the magnitude and sign of the fluctuations in correlated time series, which is a simple and useful approach to distinguish between systems with different dynamical properties but the same linear correlations. First, we decompose artificial long-range power-law linearly correlated time series into magnitude and sign series derived from the consecutive increments in the original series, and we study their correlation properties. We find analytical expressions for the correlation exponent of the sign series as a function of the exponent of the original series. Such expressions are necessary for modeling surrogate time series with desired scaling properties. Next, we study linear and nonlinear correlation properties of series composed as products of independent magnitude and sign series. These surrogate series can be considered as a zero-order approximation to the analysis of the coupling of magnitude and sign in real data, a problem still open in many fields. We find analytical results for the scaling behavior of the composed series as a function of the correlation exponents of the magnitude and sign series used in the composition, and we determine the ranges of magnitude and sign correlation exponents leading to either single scaling or to crossover behaviors. Finally, we obtain how the linear and nonlinear properties of the composed series depend on the correlation exponents of their magnitude and sign series. Based on this information we propose a method to generate surrogate series with controlled correlation exponent and multifractal spectrum.

CD-163 correlated with symptoms (pain or discomfort) of prostatic inflammation.

PubMed

Yamamichi, Fukashi; Shigemura, Katsumi; Arakawa, Soichi; Tanaka, Kazushi; Fujisawa, Masato

2015-01-01

The purpose of this study is to identify significant immune-system related for symptom of patients with prostatic inflammation in order to investigate the etiology of prostatic inflammation which may relate to potentially chronic prostatitis (CP). We investigated the expression of immune system-related biomarkers such as Interleukin (IL) -6 (humoral immunity), CD-3 (T-lymphocyte), and CD-163 (macrophage) in prostate biopsy (PBx) specimens from patients with prostatic inflammation (without cancer) which had been neither clinically diagnosed benign prostatic hyperplasia nor chronic prostatitis. We examined the correlation between these markers' expressions and the symptom scores using the National Institutes of Health-Chronic Prostatitis Symptom Index (NIH-CPSI), International Prostate Symptom Score (IPSS)/quality of life (QOL) which are the index for lower urinary tract symptoms (LUTS). Our results showed CD-163 (macrophage) reflected pain or discomfort on NIH-CPSI scores (P=0.0389 and r=0.3307) in the patients with prostatic inflammation; however, the control patients had no significant correlation between symptom scores and those immune-related markers' expression. These results suggest that pain or discomfort related to macrophages in the relationship between immune-system and the symptom of prostatic inflammation. In conclusion, CD-163, related to immune-system (macrophage), correlated with symptoms (pain or discomfort) of prostatic inflammation and might represent a significant immune-system related biomarker for pain or LUTS score in potentially CP.

Quantum Gibbs Samplers: The Commuting Case

NASA Astrophysics Data System (ADS)

Kastoryano, Michael J.; Brandão, Fernando G. S. L.

2016-06-01

We analyze the problem of preparing quantum Gibbs states of lattice spin Hamiltonians with local and commuting terms on a quantum computer and in nature. Our central result is an equivalence between the behavior of correlations in the Gibbs state and the mixing time of the semigroup which drives the system to thermal equilibrium (the Gibbs sampler). We introduce a framework for analyzing the correlation and mixing properties of quantum Gibbs states and quantum Gibbs samplers, which is rooted in the theory of non-commutative {mathbb{L}_p} spaces. We consider two distinct classes of Gibbs samplers, one of them being the well-studied Davies generator modelling the dynamics of a system due to weak-coupling with a large Markovian environment. We show that their spectral gap is independent of system size if, and only if, a certain strong form of clustering of correlations holds in the Gibbs state. Therefore every Gibbs state of a commuting Hamiltonian that satisfies clustering of correlations in this strong sense can be prepared efficiently on a quantum computer. As concrete applications of our formalism, we show that for every one-dimensional lattice system, or for systems in lattices of any dimension at temperatures above a certain threshold, the Gibbs samplers of commuting Hamiltonians are always gapped, giving an efficient way of preparing the associated Gibbs states on a quantum computer.

Skin collagen can be accurately quantified through noninvasive optical method: Validation on a swine study.

PubMed

Tzeng, S-Y; Kuo, T-Y; Hu, S-B; Chen, Y-W; Lin, Y-L; Chu, K-Y; Tseng, S-H

2018-02-01

Diffuse reflectance spectroscopy (DRS) is a noninvasive optical technology characterized by relatively low system cost and high efficiency. In our previous study, we quantified the relative concentration of collagen for the individual keloid patient. However, no actual value of collagen concentration can prove the reliability of collagen detection by our DRS system. Skin-mimicking phantoms were prepared using different collagen and coffee concentrations, and their chromophore concentrations were quantified using the DRS system to analyze the influence of collagen and other chromophores. Moreover, we used the animal study to compare the DRS system with the collagen evaluation of biopsy section by second-harmonic generation (SHG) microscopy at four different skin parts. In the phantom study, the result showed that coffee chromophore did not severely interfere with collagen concentration recovery. In the animal study, a positive correlation (r=.902) between the DRS system and collagen evaluation with SHG microscopy was found. We have demonstrated that the DRS system can quantify the actual values of collagen concentration and excluded the interference of other chromophores in skin-mimicking phantoms. Furthermore, a high positive correlation was found in the animal study with SHG microscopy. We consider that the DRS is a potential technique and can evaluate skin condition objectively. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

The Application of a Technique for Vector Correlation to Problems in Meteorology and Oceanography.

NASA Astrophysics Data System (ADS)

Breaker, L. C.; Gemmill, W. H.; Crosby, D. S.

1994-11-01

In a recent study, Crosby et al. proposed a definition for vector correlation that has not been commonly used in meteorology or oceanography. This definition has both a firm theoretical basis and a rather complete set of desirable statistical properties. In this study, the authors apply the definition to practical problems arising in meteorology and oceanography. In the first of two case studies, vector correlations were calculated between subsurface currents for five locations along the southeastern shore of Lake Erie. Vector correlations for one sample size were calculated for all current meter combinations, first including the seiche frequency and then with the seiche frequency removed. Removal of the seiche frequency, which was easily detected in the current spectra, had only a small effect on the vector correlations. Under reasonable assumptions, the vector correlations were in most cases statistically significant and revealed considerable fine structure in the vector correlation sequences. In some cases, major variations in vector correlation coincided with changes in surface wind. The vector correlations for the various current meter combinations decreased rapidly with increasing spatial separation. For one current meter combination, canonical correlations were also calculated; the first canonical correlation tended to retain the underlying trend, whereas the second canonical correlation retained the peaks in the vector correlations.In the second case study, vector correlations were calculated between marine surface winds derived from the National Meteorological Center's Global Data Assimilation System and observed winds acquired from the network of National Data Buoy Center buoys that are located off the continental United States and in the Gulf of Alaska. Results of this comparison indicated that 1) there was a significant decrease in correlation between the predicted and observed winds with increasing forecast interval out to 72 h, 2) the technique provides a sensitive indicator for detecting bad buoy reports, and 3) there was no obvious seasonal cycle in the monthly vector correlations for the period of observation.

Nanostructure studies of strongly correlated materials.

PubMed

Wei, Jiang; Natelson, Douglas

2011-09-01

Strongly correlated materials exhibit an amazing variety of phenomena, including metal-insulator transitions, colossal magnetoresistance, and high temperature superconductivity, as strong electron-electron and electron-phonon couplings lead to competing correlated ground states. Recently, researchers have begun to apply nanostructure-based techniques to this class of materials, examining electronic transport properties on previously inaccessible length scales, and applying perturbations to drive systems out of equilibrium. We review progress in this area, particularly emphasizing work in transition metal oxides (Fe(3)O(4), VO(2)), manganites, and high temperature cuprate superconductors. We conclude that such nanostructure-based studies have strong potential to reveal new information about the rich physics at work in these materials.

Validation of a prediction model that allows direct comparison of the Oxford Knee Score and American Knee Society clinical rating system.

PubMed

Maempel, J F; Clement, N D; Brenkel, I J; Walmsley, P J

2015-04-01

This study demonstrates a significant correlation between the American Knee Society (AKS) Clinical Rating System and the Oxford Knee Score (OKS) and provides a validated prediction tool to estimate score conversion. A total of 1022 patients were prospectively clinically assessed five years after TKR and completed AKS assessments and an OKS questionnaire. Multivariate regression analysis demonstrated significant correlations between OKS and the AKS knee and function scores but a stronger correlation (r = 0.68, p < 0.001) when using the sum of the AKS knee and function scores. Addition of body mass index and age (other statistically significant predictors of OKS) to the algorithm did not significantly increase the predictive value. The simple regression model was used to predict the OKS in a group of 236 patients who were clinically assessed nine to ten years after TKR using the AKS system. The predicted OKS was compared with actual OKS in the second group. Intra-class correlation demonstrated excellent reliability (r = 0.81, 95% confidence intervals 0.75 to 0.85) for the combined knee and function score when used to predict OKS. Our findings will facilitate comparison of outcome data from studies and registries using either the OKS or the AKS scores and may also be of value for those undertaking meta-analyses and systematic reviews. ©2015 The British Editorial Society of Bone & Joint Surgery.

Interleukin-6 levels in the central nervous system are negatively correlated with fat mass in overweight/obese subjects.

PubMed

Stenlöf, Kaj; Wernstedt, Ingrid; Fjällman, Ted; Wallenius, Ville; Wallenius, Kristina; Jansson, John-Olov

2003-09-01

Recently, we demonstrated that intracerebroventricular injection of IL-6 increases energy expenditure and decreases body fat in rodents. Therefore, IL-6 may play a role in appetite and body weight control in the central nervous system. In the present study we evaluated cerebrospinal fluid (CSF) and serum IL-6 levels in humans in relation to body fat content and to CSF and serum levels of leptin. Thirty-two healthy overweight/obese male subjects with a body mass index range of 29.3-36.0 kg/m(2) were studied. Total and sc body fat were measured by dual energy x-ray absorptiometry and computed tomography, respectively. CSF IL-6 levels were in some individuals higher than serum IL-6 levels and correlated negatively with total body weight, sc and total body fat. In contrast, CSF leptin levels were 30-60 times lower than serum leptin levels and correlated positively with serum leptin, body weight, sc and total body fat. Furthermore, there was a negative correlation between CSF IL-6 and leptin. In conclusion, CSF IL-6 differs in many ways from CSF leptin. CSF IL-6 may be locally produced rather than serum derived, and body fat-regulating regions in the central nervous system may be exposed to insufficient IL-6 levels in more severe obesity.

Glucocorticoid-induced leucine zipper expression is associated with response to treatment and immunoregulation in systemic lupus erythematosus.

PubMed

Mohammadi, Saeed; Ebadpour, Mohammad Reza; Sedighi, Sima; Saeedi, Mohsen; Memarian, Ali

2017-08-01

Systemic lupus erythematosus (SLE) is an autoimmune disorder in which cytokine balance is disturbed. Glucocorticoids (GCs) are shown to balance immune response by transcriptional regulation of glucocorticoid receptor target genes such as Glucocorticoid-induced leucine zipper (GILZ) which has been introduced as an endogenous anti-inflammatory mediator. In the present study, we assessed the expression of GILZ in association with interferon-γ (IFN-γ), interleukine-10 (IL-10), and B lymphocyte stimulator (BLyS) plasma levels in SLE patients. A total of 40 female patients (18 under treatment and 22 newly diagnosed) were recruited in this study. Real-time RT PCR was conducted to quantify the mRNA expression of GILZ. The plasma levels of IFN-γ, IL-10, and BLyS were evaluated using ELISA method. GILZ was overexpressed among under treatment SLE patients. The mRNA expression of GILZ was significantly correlated with Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) score. IFN-γ and BLyS were downregulated in response to therapies with negative correlations to GILZ. Moreover, IL-10 was upregulated among treated patients. The levels of IFN-γ and BLyS were correlated with the severity of disease, while IL-10 was negatively correlated with SLEDAI score. GILZ could be introduced as one of the acting molecules in mediating the regulatory effects of GCs on producing pro- and anti-inflammatory cytokines in SLE.

Repeatability of shear wave elastography in liver fibrosis phantoms—Evaluation of five different systems

PubMed Central

2018-01-01

This study aimed to assess and validate the repeatability and agreement of quantitative elastography of novel shear wave methods on four individual tissue-mimicking liver fibrosis phantoms with different known Young’s modulus. We used GE Logiq E9 2D-SWE, Philips iU22 ARFI (pSWE), Samsung TS80A SWE (pSWE), Hitachi Ascendus (SWM) and Transient Elastography (TE). Two individual investigators performed all measurements non-continued and in parallel. The methods were evaluated for inter- and intraobserver variability by intraclass correlation, coefficient of variation and limits of agreement using the median elastography value. All systems used in this study provided high repeatability in quantitative measurements in a liver fibrosis phantom and excellent inter- and intraclass correlations. All four elastography platforms showed excellent intra-and interobserver agreement (interclass correlation 0.981–1.000 and intraclass correlation 0.987–1.000) and no significant difference in mean elasticity measurements for all systems, except for TE on phantom 4. All four liver fibrosis phantoms could be differentiated by quantitative elastography, by all platforms (p<0.001). In the Bland-Altman analysis the differences in measurements were larger for the phantoms with higher Young’s modulus. All platforms had a coefficient of variation in the range 0.00–0.21 for all four phantoms, equivalent to low variance and high repeatability. PMID:29293527

Self-Other Resonance, Its Control and Prosocial Inclinations: Brain-Behavior Relationships

PubMed Central

Christov-Moore, Leonardo; Iacoboni, Marco

2016-01-01

Humans seem to place a positive reward value on prosocial behavior. Evidence suggests that this prosocial inclination is driven by our reflexive tendency to share in the observed sensations, emotions and behavior of others, or “self-other resonance”. In this study, we examine how neural correlates of self-other resonance relate to prosocial decision-making. Subjects performed two tasks while undergoing fMRI: Observation of a human hand pierced by a needle, and observation and imitation of emotional facial expressions. Outside the scanner, subjects played the Dictator Game with players of low or high income (represented by neutral-expression headshots). Subjects’ offers in the Dictator Game were correlated with activity in neural systems associated with self-other resonance and anticorrelated with activity in systems implicated in the control of pain, affect and imitation. Activity in these latter systems was specifically correlated with subjects’ diminished sharing towards players of high incomes. Functional connectivity between areas involved in self-other resonance and top-down control was negatively correlated with subjects’ offers. This study suggests that the interaction between self-other resonance and top-down control processes are an important component of prosocial inclinations towards others, even when biological stimuli associated with self-other resonance are limited. These findings support a view of prosocial decision-making that is grounded in embodied cognition. PMID:26954937

Quantum correlations in multipartite quantum systems

NASA Astrophysics Data System (ADS)

Jafarizadeh, M. A.; Heshmati, A.; Karimi, N.; Yahyavi, M.

2018-03-01

Quantum entanglement is the most famous type of quantum correlation between elements of a quantum system that has a basic role in quantum communication protocols like quantum cryptography, teleportation and Bell inequality detection. However, it has already been shown that various applications in quantum information theory do not require entanglement. Quantum discord as a new kind of quantum correlations beyond entanglement, is the most popular candidate for general quantum correlations. In this paper, first we find the entanglement witness in a particular multipartite quantum system which consists of a N-partite system in 2 n -dimensional space. Then we give an exact analytical formula for the quantum discord of this system. At the end of the paper, we investigate the additivity relation of the quantum correlation and show that this relation is satisfied for a N-partite system with 2 n -dimensional space.

Array of nanoparticles coupling with quantum-dot: Lattice plasmon quantum features

NASA Astrophysics Data System (ADS)

Salmanogli, Ahmad; Gecim, H. Selcuk

2018-06-01

In this study, we analyze the interaction of lattice plasmon with quantum-dot in order to mainly examine the quantum features of the lattice plasmon containing the photonic/plasmonic properties. Despite optical properties of the localized plasmon, the lattice plasmon severely depends on the array geometry, which may influence its quantum features such as uncertainty and the second-order correlation function. To investigate this interaction, we consider a closed system containing an array of the plasmonic nanoparticles and quantum-dot. We analyze this system with full quantum theory by which the array electric far field is quantized and the strength coupling of the quantum-dot array is analytically calculated. Moreover, the system's dynamics are evaluated and studied via the Heisenberg-Langevin equations to attain the system optical modes. We also analytically examine the Purcell factor, which shows the effect of the lattice plasmon on the quantum-dot spontaneous emission. Finally, the lattice plasmon uncertainty and its time evolution of the second-order correlation function at different spatial points are examined. These parameters are dramatically affected by the retarded field effect of the array nanoparticles. We found a severe quantum fluctuation at points where the lattice plasmon occurs, suggesting that the lattice plasmon photons are correlated.

Fuzzy logic and optical correlation-based face recognition method for patient monitoring application in home video surveillance

NASA Astrophysics Data System (ADS)

Elbouz, Marwa; Alfalou, Ayman; Brosseau, Christian

2011-06-01

Home automation is being implemented into more and more domiciles of the elderly and disabled in order to maintain their independence and safety. For that purpose, we propose and validate a surveillance video system, which detects various posture-based events. One of the novel points of this system is to use adapted Vander-Lugt correlator (VLC) and joint-transfer correlator (JTC) techniques to make decisions on the identity of a patient and his three-dimensional (3-D) positions in order to overcome the problem of crowd environment. We propose a fuzzy logic technique to get decisions on the subject's behavior. Our system is focused on the goals of accuracy, convenience, and cost, which in addition does not require any devices attached to the subject. The system permits one to study and model subject responses to behavioral change intervention because several levels of alarm can be incorporated according different situations considered. Our algorithm performs a fast 3-D recovery of the subject's head position by locating eyes within the face image and involves a model-based prediction and optical correlation techniques to guide the tracking procedure. The object detection is based on (hue, saturation, value) color space. The system also involves an adapted fuzzy logic control algorithm to make a decision based on information given to the system. Furthermore, the principles described here are applicable to a very wide range of situations and robust enough to be implementable in ongoing experiments.

Comparison of two stand-alone CADe systems at multiple operating points

NASA Astrophysics Data System (ADS)

Sahiner, Berkman; Chen, Weijie; Pezeshk, Aria; Petrick, Nicholas

2015-03-01

Computer-aided detection (CADe) systems are typically designed to work at a given operating point: The device displays a mark if and only if the level of suspiciousness of a region of interest is above a fixed threshold. To compare the standalone performances of two systems, one approach is to select the parameters of the systems to yield a target false-positive rate that defines the operating point, and to compare the sensitivities at that operating point. Increasingly, CADe developers offer multiple operating points, which necessitates the comparison of two CADe systems involving multiple comparisons. To control the Type I error, multiple-comparison correction is needed for keeping the family-wise error rate (FWER) less than a given alpha-level. The sensitivities of a single modality at different operating points are correlated. In addition, the sensitivities of the two modalities at the same or different operating points are also likely to be correlated. It has been shown in the literature that when test statistics are correlated, well-known methods for controlling the FWER are conservative. In this study, we compared the FWER and power of three methods, namely the Bonferroni, step-up, and adjusted step-up methods in comparing the sensitivities of two CADe systems at multiple operating points, where the adjusted step-up method uses the estimated correlations. Our results indicate that the adjusted step-up method has a substantial advantage over other the two methods both in terms of the FWER and power.

Monitoring Influenza Activity in the United States: A Comparison of Traditional Surveillance Systems with Google Flu Trends

PubMed Central

Ortiz, Justin R.; Zhou, Hong; Shay, David K.; Neuzil, Kathleen M.; Fowlkes, Ashley L.; Goss, Christopher H.

2011-01-01

Background Google Flu Trends was developed to estimate US influenza-like illness (ILI) rates from internet searches; however ILI does not necessarily correlate with actual influenza virus infections. Methods and Findings Influenza activity data from 2003–04 through 2007–08 were obtained from three US surveillance systems: Google Flu Trends, CDC Outpatient ILI Surveillance Network (CDC ILI Surveillance), and US Influenza Virologic Surveillance System (CDC Virus Surveillance). Pearson's correlation coefficients with 95% confidence intervals (95% CI) were calculated to compare surveillance data. An analysis was performed to investigate outlier observations and determine the extent to which they affected the correlations between surveillance data. Pearson's correlation coefficient describing Google Flu Trends and CDC Virus Surveillance over the study period was 0.72 (95% CI: 0.64, 0.79). The correlation between CDC ILI Surveillance and CDC Virus Surveillance over the same period was 0.85 (95% CI: 0.81, 0.89). Most of the outlier observations in both comparisons were from the 2003–04 influenza season. Exclusion of the outlier observations did not substantially improve the correlation between Google Flu Trends and CDC Virus Surveillance (0.82; 95% CI: 0.76, 0.87) or CDC ILI Surveillance and CDC Virus Surveillance (0.86; 95%CI: 0.82, 0.90). Conclusions This analysis demonstrates that while Google Flu Trends is highly correlated with rates of ILI, it has a lower correlation with surveillance for laboratory-confirmed influenza. Most of the outlier observations occurred during the 2003–04 influenza season that was characterized by early and intense influenza activity, which potentially altered health care seeking behavior, physician testing practices, and internet search behavior. PMID:21556151

A combined post-mortem magnetic resonance imaging and quantitative histological study of multiple sclerosis pathology

PubMed Central

Kolasinski, James; Chance, Steven A.; DeLuca, Gabriele C.; Esiri, Margaret M.; Chang, Eun-Hyuk; Palace, Jacqueline A.; McNab, Jennifer A.; Jenkinson, Mark; Miller, Karla L.; Johansen-Berg, Heidi

2012-01-01

Multiple sclerosis is a chronic inflammatory neurological condition characterized by focal and diffuse neurodegeneration and demyelination throughout the central nervous system. Factors influencing the progression of pathology are poorly understood. One hypothesis is that anatomical connectivity influences the spread of neurodegeneration. This predicts that measures of neurodegeneration will correlate most strongly between interconnected structures. However, such patterns have been difficult to quantify through post-mortem neuropathology or in vivo scanning alone. In this study, we used the complementary approaches of whole brain post-mortem magnetic resonance imaging and quantitative histology to assess patterns of multiple sclerosis pathology. Two thalamo-cortical projection systems were considered based on their distinct neuroanatomy and their documented involvement in multiple sclerosis: lateral geniculate nucleus to primary visual cortex and mediodorsal nucleus of the thalamus to prefrontal cortex. Within the anatomically distinct thalamo-cortical projection systems, magnetic resonance imaging derived cortical thickness was correlated significantly with both a measure of myelination in the connected tract and a measure of connected thalamic nucleus cell density. Such correlations did not exist between these markers of neurodegeneration across different thalamo-cortical systems. Magnetic resonance imaging lesion analysis depicted clearly demarcated subcortical lesions impinging on the white matter tracts of interest; however, quantitation of the extent of lesion-tract overlap failed to demonstrate any appreciable association with the severity of markers of diffuse pathology within each thalamo-cortical projection system. Diffusion-weighted magnetic resonance imaging metrics in both white matter tracts were correlated significantly with a histologically derived measure of tract myelination. These data demonstrate for the first time the relevance of functional anatomical connectivity to the spread of multiple sclerosis pathology in a ‘tract-specific’ pattern. Furthermore, the persisting relationship between metrics from post-mortem diffusion-weighted magnetic resonance imaging and histological measures from fixed tissue further validates the potential of imaging for future neuropathological studies. PMID:23065787

Convergence and divergence of neuroanatomic correlates and executive task performance in healthy controls and psychiatric participants.

PubMed

Ming-Tak Chung, Dennis; Jerram, Matthew W; Lee, Jonathan K; Katz, Harvey; Gansler, David A

2013-12-30

The associations between brain matter volume in the cerebral cortex and set shifting and attentional control as operationalized by the Wisconsin Card Sort Test (WCST) and Condition Three of the Delis-Kaplan version of the Color Word Interference Test (CWIT) were investigated in 15 healthy controls and 16 heterogeneously diagnosed psychiatric patients with self-control problems using voxel based morphometry. Both groups underwent standardized magnetic resonance imaging and neuropsychological assessment. WCST and CWIT variables, and a composite, were regressed across the whole brain. Although CWIT performance levels were the same in both groups, neuroanatomic correlates for the psychiatric participants invoked the left hemisphere language system, but the bilateral dorsal attention system in the healthy controls. On its own, no neuroanatomic correlates were observed for the WCST. But when part of a composite with CWIT, neuroanatomic correlates in the dorsal attention system emerged for the psychiatric participants. Psychometric combinations of manifest executive task variables may best represent higher level latent neuro-cognitive control systems. Factor analytic studies of neuropsychological test performances suggest the constructs being measured are the same across psychiatric and non-diagnosed participants, however, imaging modalities indicate the relevant neural architecture can vary by group. © 2013 Elsevier Ireland Ltd. All rights reserved.

Measurement of diabetic wounds with optical coherence tomography-based air-jet indentation system and a material testing system.

PubMed

Choi, M-C; Cheung, K-K; Ng, G Y-F; Zheng, Y-P; Cheing, G L-Y

2015-11-01

Material testing system is a conventional but destructive method for measuring the biomechanical properties of wound tissues in basic research. The recently developed optical coherence tomography-based air-jet indentation system is a non-destructive method for measuring these properties of soft tissues in a non-contact manner. The aim of the study was to examine the correlation between the biomechanical properties of wound tissues measured by the two systems. Young male Sprague-Dawley rats with streptozotocin-induced diabetic were wounded by a 6 mm biopsy punch on their hind limbs. The biomechanical properties of wound tissues were assessed with the two systems on post-wounding days 3, 7, 10, 14, and 21. Wound sections were stained with picro-sirius red for analysis on the collagen fibres. Data obtained on the different days were charted to obtain the change in biomechanical properties across the time points, and then pooled to examine the correlation between measurements made by the two devices. Qualitative analysis to determine any correlation between indentation stiffness measured by the air-jet indentation system and the orientation of collagen fibres. The indentation stiffness is significantly negatively correlated to the maximum load, maximum tensile stress, and Young's modulus by the material testing system (all p<0.05). The orientation of collagen changes with the indentation stiffness over time. Our findings support the use of optical coherence tomography-based air-jet indentation system to evaluate the biomechanical properties of wounds in a non-contact manner. It is a potential clinical device to examine the biomechanical properties of chronic wounds in vivo in a repeatable manner.

Adaptive Correlation Space Adjusted Open-Loop Tracking Approach for Vehicle Positioning with Global Navigation Satellite System in Urban Areas

PubMed Central

Ruan, Hang; Li, Jian; Zhang, Lei; Long, Teng

2015-01-01

For vehicle positioning with Global Navigation Satellite System (GNSS) in urban areas, open-loop tracking shows better performance because of its high sensitivity and superior robustness against multipath. However, no previous study has focused on the effects of the code search grid size on the code phase measurement accuracy of open-loop tracking. Traditional open-loop tracking methods are performed by the batch correlators with fixed correlation space. The code search grid size, which is the correlation space, is a constant empirical value and the code phase measuring accuracy will be largely degraded due to the improper grid size, especially when the signal carrier-to-noise density ratio (C/N0) varies. In this study, the Adaptive Correlation Space Adjusted Open-Loop Tracking Approach (ACSA-OLTA) is proposed to improve the code phase measurement dependent pseudo range accuracy. In ACSA-OLTA, the correlation space is adjusted according to the signal C/N0. The novel Equivalent Weighted Pseudo Range Error (EWPRE) is raised to obtain the optimal code search grid sizes for different C/N0. The code phase measuring errors of different measurement calculation methods are analyzed for the first time. The measurement calculation strategy of ACSA-OLTA is derived from the analysis to further improve the accuracy but reduce the correlator consumption. Performance simulation and real tests confirm that the pseudo range and positioning accuracy of ASCA-OLTA are better than the traditional open-loop tracking methods in the usual scenarios of urban area. PMID:26343683

Activation of parallel fiber feedback by spatially diffuse stimuli reduces signal and noise correlations via independent mechanisms in a cerebellum-like structure.

PubMed

Simmonds, Benjamin; Chacron, Maurice J

2015-01-01

Correlations between the activities of neighboring neurons are observed ubiquitously across systems and species and are dynamically regulated by several factors such as the stimulus' spatiotemporal extent as well as by the brain's internal state. Using the electrosensory system of gymnotiform weakly electric fish, we recorded the activities of pyramidal cell pairs within the electrosensory lateral line lobe (ELL) under spatially localized and diffuse stimulation. We found that both signal and noise correlations were markedly reduced (>40%) under the latter stimulation. Through a network model incorporating key anatomical features of the ELL, we reveal how activation of diffuse parallel fiber feedback from granule cells by spatially diffuse stimulation can explain both the reduction in signal as well as the reduction in noise correlations seen experimentally through independent mechanisms. First, we show that burst-timing dependent plasticity, which leads to a negative image of the stimulus and thereby reduces single neuron responses, decreases signal but not noise correlations. Second, we show trial-to-trial variability in the responses of single granule cells to sensory input reduces noise but not signal correlations. Thus, our model predicts that the same feedback pathway can simultaneously reduce both signal and noise correlations through independent mechanisms. To test this prediction experimentally, we pharmacologically inactivated parallel fiber feedback onto ELL pyramidal cells. In agreement with modeling predictions, we found that inactivation increased both signal and noise correlations but that there was no significant relationship between magnitude of the increase in signal correlations and the magnitude of the increase in noise correlations. The mechanisms reported in this study are expected to be generally applicable to the cerebellum as well as other cerebellum-like structures. We further discuss the implications of such decorrelation on the neural coding strategies used by the electrosensory and by other systems to process natural stimuli.

Systematic Correlation Matrix Evaluation (SCoMaE) - a bottom-up, science-led approach to identifying indicators

NASA Astrophysics Data System (ADS)

Mengis, Nadine; Keller, David P.; Oschlies, Andreas

2018-01-01

This study introduces the Systematic Correlation Matrix Evaluation (SCoMaE) method, a bottom-up approach which combines expert judgment and statistical information to systematically select transparent, nonredundant indicators for a comprehensive assessment of the state of the Earth system. The methods consists of two basic steps: (1) the calculation of a correlation matrix among variables relevant for a given research question and (2) the systematic evaluation of the matrix, to identify clusters of variables with similar behavior and respective mutually independent indicators. Optional further analysis steps include (3) the interpretation of the identified clusters, enabling a learning effect from the selection of indicators, (4) testing the robustness of identified clusters with respect to changes in forcing or boundary conditions, (5) enabling a comparative assessment of varying scenarios by constructing and evaluating a common correlation matrix, and (6) the inclusion of expert judgment, for example, to prescribe indicators, to allow for considerations other than statistical consistency. The example application of the SCoMaE method to Earth system model output forced by different CO2 emission scenarios reveals the necessity of reevaluating indicators identified in a historical scenario simulation for an accurate assessment of an intermediate-high, as well as a business-as-usual, climate change scenario simulation. This necessity arises from changes in prevailing correlations in the Earth system under varying climate forcing. For a comparative assessment of the three climate change scenarios, we construct and evaluate a common correlation matrix, in which we identify robust correlations between variables across the three considered scenarios.

Effect of beta-cyclodextrin in improving the correlation between lycopene concentration and ORAC values.

PubMed

Bangalore, Dharmendra V; McGlynn, William; Scott, Darren D

2005-03-23

Lycopene, a lipophilic antioxidant, plays a crucial role in biological systems. It may play an important role in human biological systems by providing protection against cardiovascular disease and some cancers and by boosting the immune system. The oxygen radical absorbance capacity (ORAC) has been validated as an index of antioxidant activity for many hydrophilic antioxidants but not for lycopene. This study validates the ORAC assay for different concentrations of lycopene in the presence of beta-cyclodextrin, a water-solubility enhancer. Lyc-O-Mato 6% extract was used as a source of lycopene for these experiments. Lycopene was extracted according to a standard spectrophotometric assay procedure in the presence of beta-cyclodextrin at concentrations of 0, 0.4, 0.8, and 1.6%, and the antioxidant activity of lycopene was measured with the ORAC assay. Experiments were conducted in quadruplicate and statistical pooled correlations analyzed. Statistical analysis showed a very high correlation (R2 = 0.99) between ORAC and ascorbic acid concentrations, validating this method. Lycopene concentration correlated poorly with ORAC (R2 = 0.33) in the absence of beta-cyclodextrin. Correlations improved with increasing levels of beta-cyclodextrin (R2 = 0.58 and 0.91 for 0.4 and 0.8% beta-cyclodextrin, respectively). A very high beta-cyclodextrin concentration (1.6%) decreased the correlation between ORAC and lycopene concentration. Inclusion of beta-cyclodextrin in the ORAC assay improves correlation between ORAC and lycopene concentration, thus expanding the scope of the ORAC assay to include an additional fat-soluble antioxidant.

Node Survival in Networks under Correlated Attacks

PubMed Central

Hao, Yan; Armbruster, Dieter; Hütt, Marc-Thorsten

2015-01-01

We study the interplay between correlations, dynamics, and networks for repeated attacks on a socio-economic network. As a model system we consider an insurance scheme against disasters that randomly hit nodes, where a node in need receives support from its network neighbors. The model is motivated by gift giving among the Maasai called Osotua. Survival of nodes under different disaster scenarios (uncorrelated, spatially, temporally and spatio-temporally correlated) and for different network architectures are studied with agent-based numerical simulations. We find that the survival rate of a node depends dramatically on the type of correlation of the disasters: Spatially and spatio-temporally correlated disasters increase the survival rate; purely temporally correlated disasters decrease it. The type of correlation also leads to strong inequality among the surviving nodes. We introduce the concept of disaster masking to explain some of the results of our simulations. We also analyze the subsets of the networks that were activated to provide support after fifty years of random disasters. They show qualitative differences for the different disaster scenarios measured by path length, degree, clustering coefficient, and number of cycles. PMID:25932635

Advances in Neutron Spectroscopy and High Magnetic Field Instrumentation for studies of Correlated Electron Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Granroth, Garrett E

2011-01-01

Neutron Spectroscopy has provided critical information on the magnetism in correlated electron systems. Specifically quantum magnets, superconductors, and multi-ferroics are areas of productive research. A discussion of recent measurements on the SEQUOIA spectrometer will provide examples of how novel instrumentation concepts are used on the latest generation of spectrometers to extend our knowledge in such systems. The now ubiquitous function of sample rotation allows for full mapping of volumes ofmore » $Q$ and $$\\omega$$ space. An instrument focused on low angles could extend these maps to cover more of the first Brillioun zone. Innovative chopper cascades allow two unique modes of operation. Multiplexed measurements allow the simultaneous measurement of high and low energy features in an excitation spectrum. Alternatively by limiting the neutron bandwidth incident on the Fermi Chopper, background from subsequent time frames is removed, enabling the observation of weak, large energy transfer features. Finally the implementation of event-based detection for neutron experiments is time correlated experiments. Diffraction studies of the high field spin states in MnWO$$_4$$ using magnetic fields up to 30 T, provided by a pulsed magnet, illustrate this method. Expanding the high field studies to spectroscopy will require a novel instrument, focused around a world class DC magnet, like Zeemans proposed for the SNS.« less

Cardiovascular autonomic adaptation in lunar and martian gravity during parabolic flight.

PubMed

Widjaja, Devy; Vandeput, Steven; Van Huffel, Sabine; Aubert, André E

2015-06-01

Weightlessness has a well-known effect on the autonomic control of the cardiovascular system. With future missions to Mars in mind, it is important to know what the effect of partial gravity is on the human body. We aim to study the autonomic response of the cardiovascular system to partial gravity levels, as present on the Moon and on Mars, during parabolic flight. ECG and blood pressure were continuously recorded during parabolic flight. A temporal analysis of blood pressure and heart rate to changing gravity was conducted to study the dynamic response. In addition, cardiovascular autonomic control was quantified by means of heart rate (HR) and blood pressure (BP) variability measures. Zero and lunar gravity presented a biphasic cardiovascular response, while a triphasic response was noted during martian gravity. Heart rate and blood pressure are positively correlated with gravity, while the general variability of HR and BP, as well as vagal indices showed negative correlations with increasing gravity. However, the increase in vagal modulation during weightlessness is not in proportion when compared to the increase during partial gravity. Correlations were found between the gravity level and modulations in the autonomic nervous system during parabolic flight. Nevertheless, with future Mars missions in mind, more studies are needed to use these findings to develop appropriate countermeasures.

Correlation of morphological and molecular parameters for colon cancer

NASA Astrophysics Data System (ADS)

Yuan, Shuai; Roney, Celeste A.; Li, Qian; Jiang, James; Cable, Alex; Summers, Ronald M.; Chen, Yu

2010-02-01

Colorectal cancer (CRC) is the second leading cause of cancer death in the United States. There is great interest in studying the relationship among microstructures and molecular processes of colorectal cancer during its progression at early stages. In this study, we use our multi-modality optical system that could obtain co-registered optical coherence tomography (OCT) and fluorescence molecular imaging (FMI) images simultaneously to study CRC. The overexpressed carbohydrate α-L-fucose on the surfaces of polyps facilitates the bond of adenomatous polyps with UEA-1 and is used as biomarker. Tissue scattering coefficient derived from OCT axial scan is used as quantitative value of structural information. Both structural images from OCT and molecular images show spatial heterogeneity of tumors. Correlations between those values are analyzed and demonstrate that scattering coefficients are positively correlated with FMI signals in conjugated. In UEA-1 conjugated samples (8 polyps and 8 control regions), the correlation coefficient is ranged from 0.45 to 0.99. These findings indicate that the microstructure of polyps is changed gradually during cancer progression and the change is well correlated with certain molecular process. Our study demonstrated that multi-parametric imaging is able to simultaneously detect morphology and molecular information and it can enable spatially and temporally correlated studies of structure-function relationships during tumor progression.

Combat Casualty Hand Burns: Evaluating Impairment and Disability during Recovery

DTIC Science & Technology

2008-06-01

impairment guidelines would correlate with disability as mea- sured by the DASH. However, a study by Mink van der Molen et al. found only a weak correlation (r...Mink van der Molen AB, Ettema AM, Hovius SER. Outcome of hand trauma: the hand injury severity scoring system (HISS) and subsequent impairment and...0.38) between AMA and DASH scores at six months after hand trauma.16 In another study, van Oosterom et al. reported no statistically significant

Coarse-Grained Theory of Biological Charge Transfer with Spatially and Temporally Correlated Noise.

PubMed

Liu, Chaoren; Beratan, David N; Zhang, Peng

2016-04-21

System-environment interactions are essential in determining charge-transfer (CT) rates and mechanisms. We developed a computationally accessible method, suitable to simulate CT in flexible molecules (i.e., DNA) with hundreds of sites, where the system-environment interactions are explicitly treated with numerical noise modeling of time-dependent site energies and couplings. The properties of the noise are tunable, providing us a flexible tool to investigate the detailed effects of correlated thermal fluctuations on CT mechanisms. The noise is parametrizable by molecular simulation and quantum calculation results of specific molecular systems, giving us better molecular resolution in simulating the system-environment interactions than sampling fluctuations from generic spectral density functions. The spatially correlated thermal fluctuations among different sites are naturally built-in in our method but are not readily incorporated using approximate spectral densities. Our method has quantitative accuracy in systems with small redox potential differences (

Flow Boiling Critical Heat Flux in Reduced Gravity

NASA Technical Reports Server (NTRS)

Mudawar, Issam; Zhang, Hui; Hasan, Mohammad M.

2004-01-01

This study provides systematic method for reducing power consumption in reduced gravity systems by adopting minimum velocity required to provide adequate CHF and preclude detrimental effects of reduced gravity . This study proves it is possible to use existing 1 ge flow boiling and CHF correlations and models to design reduced gravity systems provided minimum velocity criteria are met

Study of reflection and transport in the microwave photo-excited GaAs/AlGaAs two dimensional electron system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ye, Tianyu; Mani, Ramesh G.; Wegscheider, Werner

2013-12-04

We present the results of a concurrent experimental study of microwave reflection and transport in the GaAs/AlGaAs two dimensional electron gas system and correlate observed features in the reflection with the observed transport features. The experimental results are compared with expectations based on theory.

Dosimetry for radiobiological studies of the human hematopoietic system

NASA Technical Reports Server (NTRS)

Beck, W. L.; Stokes, T. R.; Lushbaugh, C. C.

1972-01-01

A system for estimating individual bone marrow doses in therapeutic radiation exposures of leukemia patients was studied. These measurements are used to make dose response correlations and to study the effect of dose protraction on peripheral blood cell levels. Three irradiators designed to produce a uniform field of high energy gamma radiation for total body exposures of large animals and man are also used for radiobiological studies.

How Volatilities Nonlocal in Time Affect the Price Dynamics in Complex Financial Systems

PubMed Central

Tan, Lei; Zheng, Bo; Chen, Jun-Jie; Jiang, Xiong-Fei

2015-01-01

What is the dominating mechanism of the price dynamics in financial systems is of great interest to scientists. The problem whether and how volatilities affect the price movement draws much attention. Although many efforts have been made, it remains challenging. Physicists usually apply the concepts and methods in statistical physics, such as temporal correlation functions, to study financial dynamics. However, the usual volatility-return correlation function, which is local in time, typically fluctuates around zero. Here we construct dynamic observables nonlocal in time to explore the volatility-return correlation, based on the empirical data of hundreds of individual stocks and 25 stock market indices in different countries. Strikingly, the correlation is discovered to be non-zero, with an amplitude of a few percent and a duration of over two weeks. This result provides compelling evidence that past volatilities nonlocal in time affect future returns. Further, we introduce an agent-based model with a novel mechanism, that is, the asymmetric trading preference in volatile and stable markets, to understand the microscopic origin of the volatility-return correlation nonlocal in time. PMID:25723154

Spaced antenna diversity in temperate latitude meteor burst systems operating near 40 MHz - Variation of signal cross-correlation coefficients with antenna separation

NASA Astrophysics Data System (ADS)

Cannon, Paul S.; Shukla, Anil K.; Lester, Mark

1993-04-01

We have studied 37-MHz signals received over an 800-km temperate latitude path using 400-W continuous wave transmissions. Signals collected during a 9-day period in February 1990 on two antennas at separations of 5, 10, and 20 lambda were analyzed. Three signal categories were identified (overdense, underdense, and not known (NK)) and cross-correlation coefficients between the signals received by the two antennas were calculated for each signal category. No spatial variation, and in particular no decrease, in average cross-correlation coefficient was observed for underdense or NK signals as the antenna spacing was increased from 5 to 20 lambda. At each antenna separation the cross-correlation coefficients of these two categories were strongly dependent on time. Overdense signals, however, showed no cross-correlation time dependency at 5 and 10 lambda, but there was a strong time dependency at 20 lambda. Recommendations are made in regard to the optimum antenna spacing for a meteor burst communication system using spaced antenna diversity.

Heat perturbation spreading in the Fermi-Pasta-Ulam-β system with next-nearest-neighbor coupling: Competition between phonon dispersion and nonlinearity

NASA Astrophysics Data System (ADS)

Xiong, Daxing

2017-06-01

We employ the heat perturbation correlation function to study thermal transport in the one-dimensional Fermi-Pasta-Ulam-β lattice with both nearest-neighbor and next-nearest-neighbor couplings. We find that such a system bears a peculiar phonon dispersion relation, and thus there exists a competition between phonon dispersion and nonlinearity that can strongly affect the heat correlation function's shape and scaling property. Specifically, for small and large anharmoncities, the scaling laws are ballistic and superdiffusive types, respectively, which are in good agreement with the recent theoretical predictions; whereas in the intermediate range of the nonlinearity, we observe an unusual multiscaling property characterized by a nonmonotonic delocalization process of the central peak of the heat correlation function. To understand these multiscaling laws, we also examine the momentum perturbation correlation function and find a transition process with the same turning point of the anharmonicity as that shown in the heat correlation function. This suggests coupling between the momentum transport and the heat transport, in agreement with the theoretical arguments of mode cascade theory.

Local and systemic oxidative stress and glucocorticoid receptor levels in chronic obstructive pulmonary disease patients

PubMed Central

Zeng, Mian; Li, Yue; Jiang, Yujie; Lu, Guifang; Huang, Xiaomei; Guan, Kaipan

2013-01-01

BACKGROUND: Previous studies have indicated that oxidative stress plays an important role in the pathogenesis of chronic obstructive pulmonary disease (COPD). OBJECTIVES: To study local and systemic oxidative stress status in COPD patients, and to clarify the relationship between local and systemic oxidative stress. METHODS: Lipid peroxide malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD) and GSH peroxidase (GSH-PX) levels in induced sputum and plasma, as well as glucocorticoid receptor (GR) levels in peripheral blood leukocytes were examined in 43 acute exacerbation of COPD patients (group A), 35 patients with stable COPD (group B) and 28 healthy controls (14 smokers [group C]; 14 nonsmokers [group D]). RESULTS: MDA levels in induced sputum and plasma decreased progressively in groups A to D, with significant differences between any two groups (P<0.001). GSH, SOD and GSH-PX levels in both induced sputum and plasma increased progressively in groups A to D, with significant differences between any two groups (P<0.001). GR levels in peripheral blood leukocytes decreased progressively in groups D to A (all comparisons P<0.001). Pearson analysis revealed strong correlations between MDA, GSH, SOD and GSH-PX levels in plasma and induced sputum. The activity of SOD in plasma and sputum were both positively correlated with GR levels (partial correlation coefficients 0.522 and 0.574, respectively [P<0.001]). CONCLUSIONS: Oxidative stress levels were elevated in COPD patients. There was a correlation between local and systemic oxidative status in COPD, and between decreased SOD activity and decreased GR levels in COPD patients. PMID:23457673

Biomechanical properties of the forefoot plantar soft tissue as measured by an optical coherence tomography-based air-jet indentation system and tissue ultrasound palpation system.

PubMed

Chao, Clare Y L; Zheng, Yong-Ping; Huang, Yan-Ping; Cheing, Gladys L Y

2010-07-01

The forefoot medial plantar area withstand high plantar pressure during locomotion, and is a common site that develops foot lesion problems among elderly people. The aims of the present study were to (1) determine the correlation between the biomechanical properties of forefoot medial plantar soft tissue measured by a newly developed optical coherence tomography-based air-jet indentation system and by tissue ultrasound palpation system, and (2) to compare the biomechanical properties of plantar soft tissues of medial forefoot between a young and old adult group. Thirty healthy subjects were classified as the young or older group. The biomechanical properties of plantar soft tissues measured at the forefoot by the air-jet indentation system and tissue ultrasound palpation system were performed, and the correlation of the findings obtained in the two systems were compared. A strong positive correlation was obtained from the findings in the two systems (r=0.88, P<0.001). The forefoot plantar soft tissue of the older group was significantly stiffer at the second metatarsal head and thinner at both metatarsal heads than that of the young group (all P<0.05). The stiffness coefficient at the second metatarsal head was 28% greater than that at the first metatarsal head in both study groups. Older subjects showed a loss of elasticity and reduced thickness in their forefoot plantar soft tissue, with the second metatarsal head displaying stiffer and thicker plantar tissue than the first metatarsal head. The air-jet indentation system is a useful instrument for characterizing the biomechanical properties of soft tissue. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Subaperture correlation based digital adaptive optics for full field optical coherence tomography.

PubMed

Kumar, Abhishek; Drexler, Wolfgang; Leitgeb, Rainer A

2013-05-06

This paper proposes a sub-aperture correlation based numerical phase correction method for interferometric full field imaging systems provided the complex object field information can be extracted. This method corrects for the wavefront aberration at the pupil/ Fourier transform plane without the need of any adaptive optics, spatial light modulators (SLM) and additional cameras. We show that this method does not require the knowledge of any system parameters. In the simulation study, we consider a full field swept source OCT (FF SSOCT) system to show the working principle of the algorithm. Experimental results are presented for a technical and biological sample to demonstrate the proof of the principle.

Dynamic entanglement transfer in a double-cavity optomechanical system

NASA Astrophysics Data System (ADS)

Huan, Tiantian; Zhou, Rigui; Ian, Hou

2015-08-01

We give a theoretical study of a double-cavity system in which a mechanical resonator beam is coupled to two cavity modes on both sides through radiation pressures. The indirect coupling between the cavities via the resonator sets up a correlation in the optomechanical entanglements between the two cavities with the common resonator. This correlation initiates an entanglement transfer from the intracavity photon-phonon entanglements to an intercavity photon-photon entanglement. Using numerical solutions, we show two distinct regimes of the optomechanical system, in which the indirect entanglement either builds up and eventually saturates or undergoes a death-and-revival cycle, after a time lapse for initiating the cooperative motion of the left and right cavity modes.

Quantum Liquid Crystal Phases in Strongly Correlated Fermionic Systems

ERIC Educational Resources Information Center

Sun, Kai

2009-01-01

This thesis is devoted to the investigation of the quantum liquid crystal phases in strongly correlated electronic systems. Such phases are characterized by their partially broken spatial symmetries and are observed in various strongly correlated systems as being summarized in Chapter 1. Although quantum liquid crystal phases often involve…

Theoretical Studies of the Kinetics of First-Order Phase Transitions.

NASA Astrophysics Data System (ADS)

Zheng, Qiang

This thesis involves theoretical studies of the kinetics of orderings in three classes of systems. The first class involves problems of phase separation in which the order parameter is conserved, such as occurs in the binary alloy Al-Zn. A theory is developed for the late stages of phase separation in the droplet regime for two -dimensional systems, namely, Ostwald ripening in two dimensions. The theory considers droplet correlations, which was neglected before, by a proper treatment of the screening effect of the correlations. This correlation effect is found that it does not alert the scaling features of phase separation, but significantly changes the shape of droplet-size distribution function. Further experiments and computer simulations are needed before this long-time subject may be closed. A second class of problem involves a study of the finite-size effects on domain growth described by the Allen-Cahn dynamics. Based on a theoretical approach of Ohta, Jasnow, and Kawasaki the explicit scaling functions for the scattering intensity for hypercubes and films are obtained. These results are for the cases in which the order-parameter is not conserved, such as in an order-disorder transition in alloys. These studies will be relevant to the experimental and computer simulation research projects currently being carried out in the United States and Europe. The last class of problems involves orderings in strong correlated systems, namely, the growth of Breath Figures. A special feature of this class of problems is that the coalescence effect. A theoretical model is proposed which can handle the two growth mechanisms, the individual droplet growth and coalescence simultaneously. Under certain approximations, the droplet-size distribution function is obtained analytically, and is in qualitative agreement with computer simulations. Our model also suggests that there may be an interesting relationship between the growth of Breath Figures and a geometric structure (ultrametricity) of general complex systems.

High-speed holographic correlation system for video identification on the internet

NASA Astrophysics Data System (ADS)

Watanabe, Eriko; Ikeda, Kanami; Kodate, Kashiko

2013-12-01

Automatic video identification is important for indexing, search purposes, and removing illegal material on the Internet. By combining a high-speed correlation engine and web-scanning technology, we developed the Fast Recognition Correlation system (FReCs), a video identification system for the Internet. FReCs is an application thatsearches through a number of websites with user-generated content (UGC) and detects video content that violates copyright law. In this paper, we describe the FReCs configuration and an approach to investigating UGC websites using FReCs. The paper also illustrates the combination of FReCs with an optical correlation system, which is capable of easily replacing a digital authorization sever in FReCs with optical correlation.

Change Point Detection in Correlation Networks

NASA Astrophysics Data System (ADS)

Barnett, Ian; Onnela, Jukka-Pekka

2016-01-01

Many systems of interacting elements can be conceptualized as networks, where network nodes represent the elements and network ties represent interactions between the elements. In systems where the underlying network evolves, it is useful to determine the points in time where the network structure changes significantly as these may correspond to functional change points. We propose a method for detecting change points in correlation networks that, unlike previous change point detection methods designed for time series data, requires minimal distributional assumptions. We investigate the difficulty of change point detection near the boundaries of the time series in correlation networks and study the power of our method and competing methods through simulation. We also show the generalizable nature of the method by applying it to stock price data as well as fMRI data.

The Bethesda system for reporting thyroid cytopathology in Colombia: Correlation with histopathological diagnoses in oncology and non-oncology institutions

PubMed Central

Melo-Uribe, Mario Alexander; Sanabria, Álvaro; Romero-Rojas, Alfredo; Pérez, Gabriel; Vargas, Elga Johanna; Abaúnza, María Claudia; Gutiérrez, Víctor

2015-01-01

Aim: To determine the correlation between the results of thyroid fine-needle aspirations interpreted using the Bethesda system and final histopathological reports for patients at an oncology hospital (OH) and non-oncology hospitals (NOHs). Materials and Methods: A retrospective, cross-sectional, descriptive study was performed to compare the cytology and histopathology results for patients with thyroid nodules in three Colombian hospitals. The final correlation of diagnoses between the two methods is reported. In Colombia, the health system provides the existence of general care hospitals and hospitals specializing in care of patients with cancer. Results: A total of 196 reports were reviewed, of which 53% were from OH and 47% were from NOHs. A greater proportion of category V (37.5%) was diagnosed at the OH, whereas NOHs diagnosed a greater proportion of category II (42.3%). The global correlation between diagnoses made using cytology and histopathology was 93.3% for categories V and VI (based on the final malignant diagnosis) and 86.9% for benign category II. Significant differences between institution types were observed when category IV and V and malignant histopathology were compared (56.3% OH vs. 23.5% NOH; P = 0.05 for category IV, 97.4% OH vs. 82.3% NOH; P = 0.03 for category V), while no significant difference between institution types was observed when category II and final benign diagnosis were compared (P = 0.6). Conclusions: The Bethesda system for thyroid cytology correlates adequately with final histopathological diagnosis in Colombia. Significant differences were identified in the diagnostic correlation for malignant lesions between the OH and NOHs in categories IV and V caused by selection bias of the population. PMID:25948937

Performance Monitoring Applied to System Supervision

PubMed Central

Somon, Bertille; Campagne, Aurélie; Delorme, Arnaud; Berberian, Bruno

2017-01-01

Nowadays, automation is present in every aspect of our daily life and has some benefits. Nonetheless, empirical data suggest that traditional automation has many negative performance and safety consequences as it changed task performers into task supervisors. In this context, we propose to use recent insights into the anatomical and neurophysiological substrates of action monitoring in humans, to help further characterize performance monitoring during system supervision. Error monitoring is critical for humans to learn from the consequences of their actions. A wide variety of studies have shown that the error monitoring system is involved not only in our own errors, but also in the errors of others. We hypothesize that the neurobiological correlates of the self-performance monitoring activity can be applied to system supervision. At a larger scale, a better understanding of system supervision may allow its negative effects to be anticipated or even countered. This review is divided into three main parts. First, we assess the neurophysiological correlates of self-performance monitoring and their characteristics during error execution. Then, we extend these results to include performance monitoring and error observation of others or of systems. Finally, we provide further directions in the study of system supervision and assess the limits preventing us from studying a well-known phenomenon: the Out-Of-the-Loop (OOL) performance problem. PMID:28744209

The relationship between brain behavioral systems and the characteristics of the five factor model of personality with aggression among Iranian students.

PubMed

Komasi, Saeid; Saeidi, Mozhgan; Soroush, Ali; Zakiei, Ali

2016-07-01

Aggression is one of the negative components of emotion and it is usually considered to be the outcome of the activity of the Behavioral Inhibition and the Behavioral Activation System (BIS/BAS): components which can be considered as predisposing factors for personality differences. Therefore, the purpose of this study was to investigate the relationship between brain behavioral systems and the characteristics of the five factor model of personality with aggression among students. The present study has a correlation descriptive design. The research population included all of the Razi University students in the academic year of 2012-2013. The sampling was carried out with a random stratified method and 360 people (308 female and 52 male) were studied according to a table of Morgan. The study instruments were Buss and Perry Aggression Questionnaire, NEO Personality Inventory (Short Form), and Carver and White scale for BAS/BIS. Finally, SPSS20 was utilized to analyze the data using Pearson correlation, regression analysis, and canonical correlation. The data showed a significant positive relationship between the neurosis and agreeableness personality factors with aggression; but there is a significant negative relationship between the extroversion, openness, and conscientiousness personality factors with aggression. Furthermore, there is a significant positive relationship between all the components of brain behavioral systems (impulsivity, novelty seeking, sensitivity, tender) and aggression. The results of regression analysis indicated the personality characteristics and the brain behavioral systems which can predict 29 percent of the changes to aggression, simultaneously. According to a predictable level of aggressiveness by the personality characteristics and brain behavioral systems, it is possible to identify the personality characteristics and template patterns of brain behavioral systems for the students which be presented to them as a necessary training in order to control and manage of anger and aggression. © 2016 KUMS, All rights reserved.

Private health care expenditure and quality in Beveridge systems: cross-regional differences in the Italian NHS.

PubMed

Del Vecchio, Mario; Fenech, Lorenzo; Prenestini, Anna

2015-03-01

Private health care expenditure ranges from 15% to 30% of total healthcare spending in OECD countries. The literature suggests that there should be an inverse correlation between quality of public services and private expenditures. The main objective of this study is to explore the association between quality of public healthcare and private expenditures in the Italian Regional Healthcare Systems (RHSs). The institutional framework offered by the Italian NHS allows to investigate on the differences among the regions while controlling for institutional factors. The study uses micro-data from the ISTAT Household Consumption Survey (HCS) and a rich set of regional quality indicators. The results indicate that there is a positive and significant correlation between quality and private spending per capita across regions. The study also points out the strong association between the distribution of private consumption and income. In order to account for the influence of income, the study segmented data in three socio-economic classes and computed cross-regional correlations of RHSs quality and household healthcare expenditure per capita, within each class. No correlation was found between the two variables. These findings are quite surprising and call into question the theory that better quality of public services crowds out private spending, or, at the very least, it undermines the simplistic notions that higher levels of private spending are a direct consequence of poor quality in the public sector. This suggests that policies should avoid to simplistically link private spending with judgements or assessments about the functioning or efficacy of the public system and its organizations. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Effect of all-trans retinoic acid treatment on prohibitin and renin-angiotensin-aldosterone system expression in hypoxia-induced renal tubular epithelial cell injury.

PubMed

Zhou, Tian-Biao; Ou, Chao; Rong, Liang; Drummen, Gregor P C

2014-09-01

All-trans retinoic acid (ATRA) exerts various effects on physiological processes such as cell growth, differentiation, apoptosis and inflammation. Prohibitins (PHB), including prohibitin 1 (PHB1) and prohibitin 2 (PHB2), are evolutionary conserved and pleiotropic proteins implicated in various cellular functions, including proliferation, tumor suppression, apoptosis, transcription, and mitochondrial protein folding. The renin-angiotensin-aldosterone system plays a pivotal role in the regulation of blood pressure and volume homeostasis. All these factors and systems have been implicated in renal interstitial fibrosis. Therefore, the objective of this study was to investigate the effect of ATRA treatment on the renin-angiotensin-aldosterone system and expression of prohibitins to further understand its role in the processes leading to renal interstitial fibrosis. The hypoxic and oxidative stress conditions in obstructive renal disease were simulated in a hypoxia/reoxygenation model with renal tubular epithelial cells (RTEC) as a model system. Subsequently, the effect of ATRA on mRNA and protein expression levels was determined and correlations were established between factors involved in the renin-angiotensin-aldosterone system, the prohibitins, cellular redox status, renal interstitial fibrosis and ATRA treatment. Correlation analysis showed that both PHB1 and PHB2 protein levels were negatively correlated with angiotensin I, ACE1, angiotensin II, TGF-β1, Col-IV, FN, ROS, and MDA (PHB1: r = -0.792, -0.834, -0.805, -0.795, -0.778, -0.798, -0.751, -0.682; PHB2: r = -0.872, -0.799, -0.838, -0.773, -0.769, -0.841, -0.794, -0.826; each p < 0.05), but positively correlated with ACE2, SOD, and GSH (PHB1: r = 0.796, 0.879, 0.824; PHB2: r = 0.785, 0.914, 0.849; each p < 0.05). ACE1 was positively correlated with angiotensin I, angiotensin II, TGF-β1, Col-IV, FN, ROS, and MDA, and negatively correlated with ACE2, SOD, and GSH (each p < 0.05). ACE2 was negatively correlated with ACE1, angiotensin I, angiotensin II, TGF-β1, Col-IV, FN, ROS, and MDA, and positively correlated with SOD and GSH (each p < 0.05). The results suggest that ATRA acts as a positive regulator of PHB1, PHB2 and ACE2, and as a negative regulator of ACE1, angiotensin I, and angiotensin II in a RTEC model system under hypoxia/reoxygenation conditions. © The Author(s) 2014.

The human foramen magnum--normal anatomy of the cisterna magna in adults.

PubMed

Whitney, Nathaniel; Sun, Hai; Pollock, Jeffrey M; Ross, Donald A

2013-11-01

The goal of this study was to radiologically describe the anatomical characteristics of the cisterna magna (CM) with regard to presence, dimension, and configuration. In this retrospective study, 523 records were reviewed. We defined five CM types, the range of which covered all normal variants found in the study population. Characteristics of the CM were recorded and correlations between various posterior fossa dimensions and CM volume determined. There were 268 female (mean age 50.9 ± 16.9 years) and 255 male (mean age 54.1 ± 15.8 years) patients. CM volume was smaller in females than in males and correlated with age (Pearson correlation, r = 0.1494, p = 0.0006) and gender (unpaired t test, r (2) = 0.0608, p < 0.0001). Clivus length correlated with CM volume (Pearson correlation, r = 0.211, p < 0.0001) and gender (unpaired t test, r (2) = 0.2428, p < 0.0001). Tentorial angle did not correlate with CM volume (Pearson correlation, r = -0.0609, p < 0.1642) but did correlate with gender (unpaired t test, r (2) = 0.0163, p < 0.0035). The anterior-posterior dimension of cerebrospinal fluid anterior to the brainstem correlated with CM volume (Pearson correlation, r = 0.181, p < 0.0001) and gender (unpaired t test, r (2) = 0.0205, p = 0.001). The anatomical description and simple classification system we define allows for a more precise description of posterior fossa anatomy and could potentially contribute to the understanding of Chiari malformation anatomy and management.

A Correlation of Quality Reviews and Fourth Grade Performance in English Language Arts

ERIC Educational Resources Information Center

Sutherland, Ann V.

2012-01-01

This study was conducted to determine if there is a relationship between two of New York City's accountability tools, and, if so, to what the extent this correlation exists. The ongoing calls for school reform have left individual states and school systems initiating one program after another in an effort to improve student achievement. New York…

20 Meter Solar Sail Analysis and Correlation

NASA Technical Reports Server (NTRS)

Taleghani, B.; Lively, P.; Banik, J.; Murphy, D.; Trautt, T.

2005-01-01

This presentation discusses studies conducted to determine the element type and size that best represents a 20-meter solar sail under ground-test load conditions, the performance of test/Analysis correlation by using Static Shape Optimization Method for Q4 sail, and system dynamic. TRIA3 elements better represent wrinkle patterns than do QUAD3 elements Baseline, ten-inch elements are small enough to accurately represent sail shape, and baseline TRIA3 mesh requires a reasonable computation time of 8 min. 21 sec. In the test/analysis correlation by using Static shape optimization method for Q4 sail, ten parameters were chosen and varied during optimization. 300 sail models were created with random parameters. A response surfaces for each targets which were created based on the varied parameters. Parameters were optimized based on response surface. Deflection shape comparison for 0 and 22.5 degrees yielded a 4.3% and 2.1% error respectively. For the system dynamic study testing was done on the booms without the sails attached. The nominal boom properties produced a good correlation to test data the frequencies were within 10%. Boom dominated analysis frequencies and modes compared well with the test results.

Nondestructive assessment of collagen hydrogel cross-linking using time-resolved autofluorescence imaging

NASA Astrophysics Data System (ADS)

Sherlock, Benjamin E.; Harvestine, Jenna N.; Mitra, Debika; Haudenschild, Anne; Hu, Jerry; Athanasiou, Kyriacos A.; Leach, J. Kent; Marcu, Laura

2018-03-01

We investigate the use of a fiber-based, multispectral fluorescence lifetime imaging (FLIm) system to nondestructively monitor changes in mechanical properties of collagen hydrogels caused by controlled application of widely used cross-linking agents, glutaraldehyde (GTA) and ribose. Postcross-linking, fluorescence lifetime images are acquired prior to the hydrogels being processed by rheological or tensile testing to directly probe gel mechanical properties. To preserve the sterility of the ribose-treated gels, FLIm is performed inside a biosafety cabinet (BSC). A pairwise correlation analysis is used to quantify the relationship between mean hydrogel fluorescence lifetimes and the storage or Young's moduli of the gels. In the GTA study, we observe strong and specific correlations between fluorescence lifetime and the storage and Young's moduli. Similar correlations are not observed in the ribose study and we postulate a reason for this. Finally, we demonstrate the ability of FLIm to longitudinally monitor dynamic cross-link formation. The strength of the GTA correlations and deployment of our fiber-based FLIm system inside the aseptic environment of a BSC suggests that this technique may be a valuable tool for the tissue engineering community where longitudinal assessment of tissue construct maturation in vitro is highly desirable.

Sampling networks with prescribed degree correlations

NASA Astrophysics Data System (ADS)

Del Genio, Charo; Bassler, Kevin; Erdos, Péter; Miklos, István; Toroczkai, Zoltán

2014-03-01

A feature of a network known to affect its structural and dynamical properties is the presence of correlations amongst the node degrees. Degree correlations are a measure of how much the connectivity of a node influences the connectivity of its neighbours, and they are fundamental in the study of processes such as the spreading of information or epidemics, the cascading failures of damaged systems and the evolution of social relations. We introduce a method, based on novel mathematical results, that allows the exact sampling of networks where the number of connections between nodes of any given connectivity is specified. Our algorithm provides a weight associated to each sample, thereby allowing network observables to be measured according to any desired distribution, and it is guaranteed to always terminate successfully in polynomial time. Thus, our new approach provides a preferred tool for scientists to model complex systems of current relevance, and enables researchers to precisely study correlated networks with broad societal importance. CIDG acknowledges support by the European Commission's FP7 through grant No. 288021. KEB acknowledges support from the NSF through grant DMR?1206839. KEB, PE, IM and ZT acknowledge support from AFSOR and DARPA through grant FA?9550-12-1-0405.

[CT morphometry for calcaneal fractures and comparison of the Zwipp and Sanders classifications].

PubMed

Andermahr, J; Jesch, A B; Helling, H J; Jubel, A; Fischbach, R; Rehm, K E

2002-01-01

The aim of the study is to correlate the CT-morphological changes of fractured calcaneus and the classifications of Zwipp and Sanders with the clinical outcome. In a retrospective clinical study, the preoperative CT scans of 75 calcaneal fractures were analysed. The morphometry of the fractures was determined by measuring height, length diameter and calcaneo-cuboidal angle in comparison to the intact contralateral side. At a mean of 38 months after trauma 44 patients were clinically followed-up. The data of CT image morphometry were correlated with the severity of fracture classified by Zwipp or Sanders as well as with the functional outcome. There was a good correlation between the fracture classifications and the morphometric data. Both fracture classifying systems have a predictive impact for functional outcome. The more exacting and accurate Zwipp classification considers the most important cofactors like involvement of the calcaneo-cuboidal joint, soft tissue damage, additional fractures etc. The Sanders classification is easier to use during clinical routine. The Zwipp classification includes more relevant cofactors (fracture of the calcaneo-cuboidal-joint, soft tissue swelling, etc.) and presents a higher correlation to the choice of therapy. Both classification systems present a prognostic impact concerning the clinical outcome.

Correlation Function Approach for Estimating Thermal Conductivity in Highly Porous Fibrous Materials

NASA Technical Reports Server (NTRS)

Martinez-Garcia, Jorge; Braginsky, Leonid; Shklover, Valery; Lawson, John W.

2011-01-01

Heat transport in highly porous fiber networks is analyzed via two-point correlation functions. Fibers are assumed to be long and thin to allow a large number of crossing points per fiber. The network is characterized by three parameters: the fiber aspect ratio, the porosity and the anisotropy of the structure. We show that the effective thermal conductivity of the system can be estimated from knowledge of the porosity and the correlation lengths of the correlation functions obtained from a fiber structure image. As an application, the effects of the fiber aspect ratio and the network anisotropy on the thermal conductivity is studied.

Failure criterion for materials with spatially correlated mechanical properties

NASA Astrophysics Data System (ADS)

Faillettaz, J.; Or, D.

2015-03-01

The role of spatially correlated mechanical elements in the failure behavior of heterogeneous materials represented by fiber bundle models (FBMs) was evaluated systematically for different load redistribution rules. Increasing the range of spatial correlation for FBMs with local load sharing is marked by a transition from ductilelike failure characteristics into brittlelike failure. The study identified a global failure criterion based on macroscopic properties (external load and cumulative damage) that is independent of spatial correlation or load redistribution rules. This general metric could be applied to assess the mechanical stability of complex and heterogeneous systems and thus provide an important component for early warning of a class of geophysical ruptures.

A Systems-Theoretical Generalization of Non-Local Correlations

NASA Astrophysics Data System (ADS)

von Stillfried, Nikolaus

Non-local correlations between quantum events are not due to a causal interaction in the sense of one being the cause for the other. In principle, the correlated events can thus occur simultaneously. Generalized Quantum Theory (GQT) formalizes the idea that non-local phenomena are not exclusive to quantum mechanics, e.g. due to some specific properties of (sub)atomic particles, but that they instead arise as a consequence of the way such particles are arranged into systems. Non-local phenomena should hence occur in any system which fulfils the necessary systems-theoretical parameters. The two most important parameters with respect to non-local correlations seem to be a conserved global property of the system as a whole and sufficient degrees of freedom of the corresponding property of its subsystems. Both factors place severe limitations on experimental observability of the phenomena, especially in terms of replicability. It has been suggested that reported phenomena of a so-called synchronistic, parapsychological or paranormal kind could be understood as instances of systems-inherent non-local correlations. From a systems-theoretical perspective, their phenomenology (including the favorable conditions for their occurrence and their lack of replicability) displays substantial similarities to non-local correlations in quantum systems and matches well with systems-theoretical parameters, thus providing circumstantial evidence for this hypothesis.

Neural correlates of dual-task effect on belief-bias syllogistic reasoning: a near-infrared spectroscopy study.

PubMed

Tsujii, Takeo; Watanabe, Shigeru

2009-09-01

Recent dual-process reasoning theories have explained the belief-bias effect, the tendency for human reasoning to be erroneously biased when logical conclusions are incongruent with beliefs about the world, by proposing a belief-based automatic heuristic system and logic-based demanding analytic system. Although these claims are supported by the behavioral finding that high-load secondary tasks enhance the belief-bias effect, the neural correlates of dual-task reasoning remain unknown. The present study therefore examined the relationship between dual-task effect and activity in the inferior frontal cortex (IFC) during belief-bias reasoning by near-infrared spectroscopy (NIRS). Forty-eight subjects participated in this study (MA=23.46 years). They were required to perform congruent and incongruent reasoning trials while responding to high- and low-load secondary tasks. Behavioral analysis showed that the high-load secondary task impaired only incongruent reasoning performance. NIRS analysis found that the high-load secondary task decreased right IFC activity during incongruent trials. Correlation analysis showed that subjects with enhanced right IFC activity could perform better in the incongruent reasoning trials, though subjects for whom right IFC activity was impaired by the secondary task could not maintain better reasoning performance. These findings suggest that the right IFC may be responsible for the dual-task effect in conflicting reasoning processes. When secondary tasks impair right IFC activity, subjects may rely on the automatic heuristic system, which results in belief-bias responses. We therefore offer the first demonstration of neural correlates of dual-task effect on IFC activity in belief-bias reasoning.

Development of a discriminative biphasic in vitro dissolution test and correlation with in vivo pharmacokinetic studies for differently formulated racecadotril granules.

PubMed

Deng, Jia; Staufenbiel, Sven; Hao, Shilei; Wang, Bochu; Dashevskiy, Andriy; Bodmeier, Roland

2017-06-10

The purpose of this study was to discriminate the release behavior from three differently formulated racecadotril (BCS II) granules and to establish an in vitro-in vivo correlation. Three granule formulations of the lipophilic drug were prepared with equivalent composition but prepared with different manufacturing processes (dry granulation, wet granulation with or without binder). In vitro release of the three granules was investigated using a biphasic dissolution system (phosphate buffer pH6.8 and octanol) and compared to the conventional single phase USP II dissolution test performed under sink and non-sink conditions. In vivo studies with each granule formulation were performed in rats. Interestingly, the granule formulations exhibited pronouncedly different behavior in the different dissolution systems depending on different wetting and dissolution conditions. Single phase USP II dissolution tests lacked discrimination. In contrast, remarkable discrimination between the granule formulations was observed in the octanol phase of biphasic dissolution system with a rank order of release from granules prepared by wet granulation with binder>wet granulation without binder>dry granulation. This release order correlated well with the wettability of these granules. An excellent correlation was also established between in vitro release in the octanol phase of the biphasic test and in vivo data (R 2 =0.999). Compared to conventional dissolution methods, the biphasic method provides great potential to discriminate between only minor formulation and process changes within the same dosage form for poorly soluble drugs. Copyright © 2017 Elsevier B.V. All rights reserved.

The role of ZAP70 kinase in acute lymphoblastic leukemia infiltration into the central nervous system.

PubMed

Alsadeq, Ameera; Fedders, Henning; Vokuhl, Christian; Belau, Nele M; Zimmermann, Martin; Wirbelauer, Tim; Spielberg, Steffi; Vossen-Gajcy, Michaela; Cario, Gunnar; Schrappe, Martin; Schewe, Denis M

2017-02-01

Central nervous system infiltration and relapse are poorly understood in childhood acute lymphoblastic leukemia. We examined the role of zeta-chain-associated protein kinase 70 in preclinical models of central nervous system leukemia and performed correlative studies in patients. Zeta-chain-associated protein kinase 70 expression in acute lymphoblastic leukemia cells was modulated using short hairpin ribonucleic acid-mediated knockdown or ectopic expression. We show that zeta-chain-associated protein kinase 70 regulates CCR7/CXCR4 via activation of extracellular signal-regulated kinases. High expression of zeta-chain-associated protein kinase 70 in acute lymphoblastic leukemia cells resulted in a higher proportion of central nervous system leukemia in xenografts as compared to zeta-chain-associated protein kinase 70 low expressing counterparts. High zeta-chain-associated protein kinase 70 also enhanced the migration potential towards CCL19/CXCL12 gradients in vitro CCR7 blockade almost abrogated homing of acute lymphoblastic leukemia cells to the central nervous system in xenografts. In 130 B-cell precursor acute lymphoblastic leukemia and 117 T-cell acute lymphoblastic leukemia patients, zeta-chain-associated protein kinase 70 and CCR7/CXCR4 expression levels were significantly correlated. Zeta-chain-associated protein kinase 70 expression correlated with central nervous system disease in B-cell precursor acute lymphoblastic leukemia, and CCR7/CXCR4 correlated with central nervous system involvement in T-cell acute lymphoblastic leukemia patients. In multivariate analysis, zeta-chain-associated protein kinase 70 expression levels in the upper third and fourth quartiles were associated with central nervous system involvement in B-cell precursor acute lymphoblastic leukemia (odds ratio=7.48, 95% confidence interval, 2.06-27.17; odds ratio=6.86, 95% confidence interval, 1.86-25.26, respectively). CCR7 expression in the upper fourth quartile correlated with central nervous system positivity in T-cell acute lymphoblastic leukemia (odds ratio=11.00, 95% confidence interval, 2.00-60.62). We propose zeta-chain-associated protein kinase 70, CCR7 and CXCR4 as markers of central nervous system infiltration in acute lymphoblastic leukemia warranting prospective investigation. Copyright© Ferrata Storti Foundation.

Observability of radiation-pressure shot noise in optomechanical systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boerkje, K.; Nunnenkamp, A.; Zwickl, B. M.

2010-07-15

We present a theoretical study of an experiment designed to detect radiation-pressure shot noise in an optomechanical system. Our model consists of a coherently driven optical cavity mode that is coupled to a mechanical oscillator. We examine the cross-correlation between two quadratures of the output field from the cavity. We determine under which circumstances radiation-pressure shot noise can be detected by a measurement of this cross-correlation. This is done in the general case of nonzero detuning between the frequency of the drive and the cavity resonance frequency. We study the qualitative features of the different contributions to the cross-correlator andmore » provide quantitative figures of merit for the relative importance of the radiation-pressure shot noise contribution to other contributions. We also propose a modified setup of this experiment relevant to the 'membrane-in-the-middle' geometry, which potentially can avoid the problems of static bistability and classical noise in the drive.« less

Shock probes in a one-dimensional Katz-Lebowitz-Spohn model

NASA Astrophysics Data System (ADS)

Chatterjee, Sakuntala; Barma, Mustansir

2008-06-01

We consider shock probes in a one-dimensional driven diffusive medium with nearest-neighbor Ising interaction (KLS model). Earlier studies based on an approximate mapping of the present system to an effective zero-range process concluded that the exponents characterizing the decays of several static and dynamical correlation functions of the probes depend continuously on the strength of the Ising interaction. On the contrary, our numerical simulations indicate that over a substantial range of the interaction strength, these exponents remain constant and their values are the same as in the case of no interaction (when the medium executes an ASEP). We demonstrate this by numerical studies of several dynamical correlation functions for two probes and also for a macroscopic number of probes. Our results are consistent with the expectation that the short-ranged correlations induced by the Ising interaction should not affect the large time and large distance properties of the system, implying that scaling forms remain the same as in the medium with no interactions present.

Fluorescence correlation spectroscopy as a method for assessment of interactions between phage displaying antibodies and soluble antigen

PubMed Central

Lagerkvist, Ann Catrin; Földes-Papp, Zeno; Persson, Mats A.A.; Rigler, Rudolf

2001-01-01

Phage display is widely used for expression of combinatorial libraries, not least for protein engineering purposes. Precise selection at the single molecule level will provide an improved tool for generating proteins with complex and distinct properties from large molecular libraries. To establish such an improved selection system, we here report the detection of specific interactions between phage with displayed antibody fragments and fluorescently labeled soluble antigen based on Fluorescence Correlation Spectroscopy (FCS). Our novel strategy comprises the use of two separate fluorochromes for detection of the phage–antigen complex, either with labeled antiphage antibody or using a labeled antigen. As a model system, we studied a human monoclonal antibody to the hepatitis-C virus (HCV) envelope protein E2 and its cognate antigen (rE2 or rE1/E2). We could thus assess the specific interactions and determine the fraction of specific versus background phage (26% specific phage). Aggregation of these particular antigens made it difficult to reliably utilize the full potential of cross-correlation studies using the two labels simultaneously. However, with true monomeric proteins, this will certainly be possible, offering a great advantage in a safer and highly specific detection system. PMID:11468349

Scaling Theory of Entanglement at the Many-Body Localization Transition.

PubMed

Dumitrescu, Philipp T; Vasseur, Romain; Potter, Andrew C

2017-09-15

We study the universal properties of eigenstate entanglement entropy across the transition between many-body localized (MBL) and thermal phases. We develop an improved real space renormalization group approach that enables numerical simulation of large system sizes and systematic extrapolation to the infinite system size limit. For systems smaller than the correlation length, the average entanglement follows a subthermal volume law, whose coefficient is a universal scaling function. The full distribution of entanglement follows a universal scaling form, and exhibits a bimodal structure that produces universal subleading power-law corrections to the leading volume law. For systems larger than the correlation length, the short interval entanglement exhibits a discontinuous jump at the transition from fully thermal volume law on the thermal side, to pure area law on the MBL side.

A frequency tunable, eight-channel correlation ECE system for electron temperature turbulence measurements on the DIII-D tokamak

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sung, C., E-mail: csung@physics.ucla.edu; Peebles, W. A.; Wannberg, C.

2016-11-15

A new eight-channel correlation electron cyclotron emission diagnostic has recently been installed on the DIII-D tokamak to study both turbulent and coherent electron temperature fluctuations under various plasma conditions and locations. This unique system is designed to cover a broad range of operation space on DIII-D (1.6-2.1 T, detection frequency: 72-108 GHz) via four remotely selected local oscillators (80, 88, 96, and 104 GHz). Eight radial locations are measured simultaneously in a single discharge covering as much as half the minor radius. In this paper, we present design details of the quasi-optical system, the receiver, as well as representative datamore » illustrating operation of the system.« less

Ultra-wideband communication system prototype using orthogonal frequency coded SAW correlators.

PubMed

Gallagher, Daniel R; Kozlovski, Nikolai Y; Malocha, Donald C

2013-03-01

This paper presents preliminary ultra-wideband (UWB) communication system results utilizing orthogonal frequency coded SAW correlators. Orthogonal frequency coding (OFC) and pseudo-noise (PN) coding provides a means for spread-spectrum UWB. The use of OFC spectrally spreads a PN sequence beyond that of CDMA; allowing for improved correlation gain. The transceiver approach is still very similar to that of the CDMA approach, but provides greater code diversity. Use of SAW correlators eliminates many of the costly components that are typically needed in the intermediate frequency (IF) section in the transmitter and receiver, and greatly reduces the signal processing requirements. Development and results of an experimental prototype system with center frequency of 250 MHz are presented. The prototype system is configured using modular RF components and benchtop pulse generator and frequency source. The SAW correlation filters used in the test setup were designed using 7 chip frequencies within the transducer. The fractional bandwidth of approximately 29% was implemented to exceed the defined UWB specification. Discussion of the filter design and results are presented and are compared with packaged device measurements. A prototype UWB system using OFC SAW correlators is demonstrated in wired and wireless configurations. OFC-coded SAW filters are used for generation of a transmitted spread-spectrum UWB and matched filter correlated reception. Autocorrelation and cross-correlation system outputs are compared. The results demonstrate the feasibility of UWB SAW correlators for use in UWB communication transceivers.

Revealing hidden antiferromagnetic correlations in doped Hubbard chains via string correlators

NASA Astrophysics Data System (ADS)

Hilker, Timon A.; Salomon, Guillaume; Grusdt, Fabian; Omran, Ahmed; Boll, Martin; Demler, Eugene; Bloch, Immanuel; Gross, Christian

2017-08-01

Topological phases, like the Haldane phase in spin-1 chains, defy characterization through local order parameters. Instead, nonlocal string order parameters can be employed to reveal their hidden order. Similar diluted magnetic correlations appear in doped one-dimensional lattice systems owing to the phenomenon of spin-charge separation. Here we report on the direct observation of such hidden magnetic correlations via quantum gas microscopy of hole-doped ultracold Fermi-Hubbard chains. The measurement of nonlocal spin-density correlation functions reveals a hidden finite-range antiferromagnetic order, a direct consequence of spin-charge separation. Our technique, which measures nonlocal order directly, can be readily extended to higher dimensions to study the complex interplay between magnetic order and density fluctuations.

Digital-Electronic/Optical Apparatus Would Recognize Targets

NASA Technical Reports Server (NTRS)

Scholl, Marija S.

1994-01-01

Proposed automatic target-recognition apparatus consists mostly of digital-electronic/optical cross-correlator that processes infrared images of targets. Infrared images of unknown targets correlated quickly with images of known targets. Apparatus incorporates some features of correlator described in "Prototype Optical Correlator for Robotic Vision System" (NPO-18451), and some of correlator described in "Compact Optical Correlator" (NPO-18473). Useful in robotic system; to recognize and track infrared-emitting, moving objects as variously shaped hot workpieces on conveyor belt.

Correlation of the clinical and physical image quality in chest radiography for average adults with a computed radiography imaging system

PubMed Central

Wood, T J; Beavis, A W; Saunderson, J R

2013-01-01

Objective: The purpose of this study was to examine the correlation between the quality of visually graded patient (clinical) chest images and a quantitative assessment of chest phantom (physical) images acquired with a computed radiography (CR) imaging system. Methods: The results of a previously published study, in which four experienced image evaluators graded computer-simulated postero-anterior chest images using a visual grading analysis scoring (VGAS) scheme, were used for the clinical image quality measurement. Contrast-to-noise ratio (CNR) and effective dose efficiency (eDE) were used as physical image quality metrics measured in a uniform chest phantom. Although optimal values of these physical metrics for chest radiography were not derived in this work, their correlation with VGAS in images acquired without an antiscatter grid across the diagnostic range of X-ray tube voltages was determined using Pearson’s correlation coefficient. Results: Clinical and physical image quality metrics increased with decreasing tube voltage. Statistically significant correlations between VGAS and CNR (R=0.87, p<0.033) and eDE (R=0.77, p<0.008) were observed. Conclusion: Medical physics experts may use the physical image quality metrics described here in quality assurance programmes and optimisation studies with a degree of confidence that they reflect the clinical image quality in chest CR images acquired without an antiscatter grid. Advances in knowledge: A statistically significant correlation has been found between the clinical and physical image quality in CR chest imaging. The results support the value of using CNR and eDE in the evaluation of quality in clinical thorax radiography. PMID:23568362

2D and 3D MOCART scoring systems assessed by 9.4 T high-field MRI correlate with elementary and complex histological scoring systems in a translational model of osteochondral repair.

PubMed

Goebel, L; Zurakowski, D; Müller, A; Pape, D; Cucchiarini, M; Madry, H

2014-10-01

To compare the 2D and 3D MOCART system obtained with 9.4 T high-field magnetic resonance imaging (MRI) for the ex vivo analysis of osteochondral repair in a translational model and to correlate the data with semiquantitative histological analysis. Osteochondral samples representing all levels of repair (sheep medial femoral condyles; n = 38) were scanned in a 9.4 T high-field MRI. The 2D and adapted 3D MOCART systems were used for grading after point allocation to each category. Each score was correlated with corresponding reconstructions between both MOCART systems. Data were next correlated with corresponding categories of an elementary (Wakitani) and a complex (Sellers) histological scoring system as gold standards. Correlations between most 2D and 3D MOCART score categories were high, while mean total point values of 3D MOCART scores tended to be 15.8-16.1 points higher compared to the 2D MOCART scores based on a Bland-Altman analysis. "Defect fill" and "total points" of both MOCART scores correlated with corresponding categories of Wakitani and Sellers scores (all P ≤ 0.05). "Subchondral bone plate" also correlated between 3D MOCART and Sellers scores (P < 0.001). Most categories of the 2D and 3D MOCART systems correlate, while total scores were generally higher using the 3D MOCART system. Structural categories "total points" and "defect fill" can reliably be assessed by 9.4 T MRI evaluation using either system, "subchondral bone plate" using the 3D MOCART score. High-field MRI is valuable to objectively evaluate osteochondral repair in translational settings. Copyright © 2014 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Ethnopedology and soil quality of bamboo (Bambusa sp.) based agroforestry system.

PubMed

Arun Jyoti, Nath; Lal, Rattan; Das, Ashesh Kumar

2015-07-15

It is widely recognized that farmers' hold important knowledge of folk soil classification for agricultural land for its uses, yet little has been studied for traditional agroforestry systems. This article explores the ethnopedology of bamboo (Bambusa sp.) based agroforestry system in North East India, and establishes the relationship of soil quality index (SQI) with bamboo productivity. The study revealed four basic folk soil (mati) types: kalo (black soil), lal (red soil), pathal (stony soil) and balu (sandy soil). Of these, lal mati soil was the most predominant soil type (~ 40%) in bamboo-based agroforestry system. Soil physio-chemical parameters were studied to validate the farmers' soil hierarchal classification and also to correlate with productivity of the bamboo stand. Farmers' hierarchal folk soil classification was consistent with the laboratory scientific analysis. Culm production (i.e. measure of productivity of bamboo) was the highest (27culmsclump(-1)) in kalo mati (black soil) and the lowest (19culmsclump(-1)) in balu mati (sandy soil). Linear correlation of individual soil quality parameter with bamboo productivity explained 16 to 49% of the variability. A multiple correlation of the best fitted linear soil quality parameter (soil organic carbon or SOC, water holding capacity or WHC, total nitrogen) with productivity improved explanatory power to 53%. Development of SQI from ten relevant soil quality parameters and its correlation with bamboo productivity explained the 64% of the variation and therefore, suggest SQI as the best determinant of bamboo yield. Data presented indicate that the kalo mati (black soil) is sustainable or sustainable with high input. However, the other three folk soil types (red, stony and sandy soil) are also sustainable but for other land uses. Therefore, ethnopedological studies may move beyond routine laboratory analysis and incorporate SQI for assessing the sustainability of land uses managed by the farmers'. Additional research is required to incorporate principal component analysis for improving the SQI and site potential assessment. It is also important to evaluate the minimum data set (MDS) required for SQI and productivity assessment in agroforestry systems. Copyright © 2015 Elsevier B.V. All rights reserved.

Genuine quantum correlations in quantum many-body systems: a review of recent progress

NASA Astrophysics Data System (ADS)

De Chiara, Gabriele; Sanpera, Anna

2018-07-01

Quantum information theory has considerably helped in the understanding of quantum many-body systems. The role of quantum correlations and in particular, bipartite entanglement, has become crucial to characterise, classify and simulate quantum many body systems. Furthermore, the scaling of entanglement has inspired modifications to numerical techniques for the simulation of many-body systems leading to the, now established, area of tensor networks. However, the notions and methods brought by quantum information do not end with bipartite entanglement. There are other forms of correlations embedded in the ground, excited and thermal states of quantum many-body systems that also need to be explored and might be utilised as potential resources for quantum technologies. The aim of this work is to review the most recent developments regarding correlations in quantum many-body systems focussing on multipartite entanglement, quantum nonlocality, quantum discord, mutual information but also other non classical measures of correlations based on quantum coherence. Moreover, we also discuss applications of quantum metrology in quantum many-body systems.

One- and two-mode squeezed light in correlated interferometry

NASA Astrophysics Data System (ADS)

Ruo-Berchera, I.; Degiovanni, I. P.; Olivares, S.; Samantaray, N.; Traina, P.; Genovese, M.

2015-11-01

We study in detail a system of two interferometers aimed at detecting extremely faint phase fluctuations. This system can represent a breakthrough for detecting a faint correlated signal that would remain otherwise undetectable even using the most sensitive individual interferometric devices, as in the case of so-called holographic noise. The signature of this kind of noise emerges as a correlation between the output signals of the interferometers. On the other hand, when holographic noise is absent one expects uncorrelated signals since the time-averaged fluctuations due to shot noise and other independent contributions vanish (though limiting the overall sensitivity). We show how injecting quantum light in the free ports of the interferometers can reduce the photon noise of the system beyond the shot noise, enhancing the resolution in the phase-correlation estimation. We analyze the use of both the two-mode squeezed vacuum and two independent squeezed states. Our results confirm the benefit of using squeezed beams together with strong coherent beams in interferometry. We also investigate the possible use of the two-mode squeezed vacuum, discovering interesting and unexplored areas of application of bipartite entanglement, in particular the possibility of reaching in principle a surprising uncertainty reduction.

Spin Solid versus Magnetic Charge Ordered State in Artificial Honeycomb Lattice of Connected Elements

PubMed Central

Glavic, Artur; Summers, Brock; Dahal, Ashutosh; Kline, Joseph; Van Herck, Walter; Sukhov, Alexander; Ernst, Arthur

2018-01-01

Abstract The nature of magnetic correlation at low temperature in two‐dimensional artificial magnetic honeycomb lattice is a strongly debated issue. While theoretical researches suggest that the system will develop a novel zero entropy spin solid state as T → 0 K, a confirmation to this effect in artificial honeycomb lattice of connected elements is lacking. This study reports on the investigation of magnetic correlation in newly designed artificial permalloy honeycomb lattice of ultrasmall elements, with a typical length of ≈12 nm, using neutron scattering measurements and temperature‐dependent micromagnetic simulations. Numerical modeling of the polarized neutron reflectometry data elucidates the temperature‐dependent evolution of spin correlation in this system. As temperature reduces to ≈7 K, the system tends to develop novel spin solid state, manifested by the alternating distribution of magnetic vortex loops of opposite chiralities. Experimental results are complemented by temperature‐dependent micromagnetic simulations that confirm the dominance of spin solid state over local magnetic charge ordered state in the artificial honeycomb lattice with connected elements. These results enable a direct investigation of novel spin solid correlation in the connected honeycomb geometry of 2D artificial structure. PMID:29721429

Pain point system scale (PPSS): a method for postoperative pain estimation in retrospective studies

PubMed Central

Gkotsi, Anastasia; Petsas, Dimosthenis; Sakalis, Vasilios; Fotas, Asterios; Triantafyllidis, Argyrios; Vouros, Ioannis; Saridakis, Evangelos; Salpiggidis, Georgios; Papathanasiou, Athanasios

2012-01-01

Purpose Pain rating scales are widely used for pain assessment. Nevertheless, a new tool is required for pain assessment needs in retrospective studies. Methods The postoperative pain episodes, during the first postoperative day, of three patient groups were analyzed. Each pain episode was assessed by a visual analog scale, numerical rating scale, verbal rating scale, and a new tool – pain point system scale (PPSS) – based on the analgesics administered. The type of analgesic was defined based on the authors’ clinic protocol, patient comorbidities, pain assessment tool scores, and preadministered medications by an artificial neural network system. At each pain episode, each patient was asked to fill the three pain scales. Bartlett’s test and Kaiser–Meyer–Olkin criterion were used to evaluate sample sufficiency. The proper scoring system was defined by varimax rotation. Spearman’s and Pearson’s coefficients assessed PPSS correlation to the known pain scales. Results A total of 262 pain episodes were evaluated in 124 patients. The PPSS scored one point for each dose of paracetamol, three points for each nonsteroidal antiinflammatory drug or codeine, and seven points for each dose of opioids. The correlation between the visual analog scale and PPSS was found to be strong and linear (rho: 0.715; P < 0.001 and Pearson: 0.631; P < 0.001). Conclusion PPSS correlated well with the known pain scale and could be used safely in the evaluation of postoperative pain in retrospective studies. PMID:23152699

The Eating and Drinking Ability Classification System: concurrent validity and reliability in children with cerebral palsy.

PubMed

Tschirren, Lea; Bauer, Susanne; Hanser, Chiara; Marsico, Petra; Sellers, Diane; van Hedel, Hubertus J A

2018-06-01

As there is little evidence for concurrent validity of the Eating and Drinking Ability Classification System (EDACS), this study aimed to determine its concurrent validity and reliability in children and adolescents with cerebral palsy (CP). After an extensive translation procedure, we applied the German language version to 52 participants with CP (30 males, 22 females, mean age 9y 7mo [SD 4y 2mo]). We correlated (Kendall's tau or K τ ) the EDACS levels with the Bogenhausener Dysphagiescore (BODS), and the EDACS level of assistance with the Manual Ability Classification System (MACS) and the item 'eating' of the Functional Independence Measure for Children (WeeFIM). We further quantified the interrater reliability between speech and language therapists (SaLTs) and between SaLTs and parents with Kappa (κ). The EDACS levels correlated highly with the BODS (K τ =0.79), and the EDACS level of assistance correlated highly with the MACS (K τ =0.73) and WeeFIM eating item (K τ =-0.80). Interrater reliability proved almost perfect between SaLTs (EDACS: κ=0.94; EDACS level of assistance: κ=0.89) and SaLTs and parents (EDACS: κ=0.82; EDACS level of assistance: κ=0.89). The EDACS levels and level of assistance seem valid and showed almost perfect interrater reliability when classifying eating and drinking problems in children and adolescents with CP. The Eating and Drinking Ability Classification System (EDACS) correlates well with a dysphagia score. The EDACS level of assistance proves valid. The German version of EDACS is highly reliable. EDACS correlates moderately to highly with other classification systems. © 2018 Mac Keith Press.

Correlations between soil respiration and soil properties in sugarcane areas under green and slash-and-burn management systems

NASA Astrophysics Data System (ADS)

Rodrigo Panosso, Alan; Milori, Débora M. B. P.; Marques Júnior, José; Martin-Neto, Ladislau; La Scala, Newton, Jr.

2010-05-01

Soil management causes changes in soil physical, chemical, and biological properties that consequently affect its CO2 emission. In this work we studied soil respiration (FCO2) in areas with sugarcane production in southern Brazil under two different sugarcane management systems: green (G), consisting of mechanized harvesting that produces a large amount of crop residues left on the soil surface, and slash-and-burn (SB), in which the residues are burned before manual harvest, leaving no residues on the soil surface. The study was conducted after the harvest period in two side-by-side grids installed in adjacent areas, having 20 measurement points each. The objective of this work was to determinate whether soil physical and chemical properties within each plot were useful in order to explain the spatial variability of FCO2, supposedly influence by each management system. Most of the soil physical properties studied showed no significant differences between management systems, but on the other hand most of the chemical properties differed significantly when SB and G areas were compared. Total FCO2 was 31% higher in the SB plot (729 g CO2 m-2) when compared to the G plot (557 g CO2 m-2) throughout the 70-day period after harvest studied. This seems to be related to the sensitivity of FCO2 to precipitation events, as respiration in this plot increased significantly with increases in soil moisture. Despite temporal variability showed to be positively related to soil moisture, inside each management system there was a negative correlation (p<0.01) between the spatial changes of FCO2 and soil moisture (MS), R= -0.56 and -0.59 for G and SB respectively. There was no spatial correlation between FCO2 and soil organic matter in each management system, however, the humification index (Hum) of organic matter was negatively linear correlated with FCO2 in SB (R= -0.53, p<0.05) while positively linear correlated in G area (R=0.42, p<0.10). The multiple regression model analysis applied in each management system indicates that 63% of the FCO2 spatial variability in G managed could be explained by the model: FCO2(G)= 4.11978 -0.07672MS + 0.0045Hum +1.5352K -0.04474FWP, where K and FWP are potassium content and free water porosity in G area, respectively. On the other hand, 75% of FCO2 spatial variability in SB managed plot was accounted by the model: FCO2(SB) = 10.66774 -0.08624MS -0.02904Hum -2.42548K. Therefore, soil moisture, humification index of organic matter and potassium level were the main properties able to explain the spatial variability of FCO2 in both sugarcane management systems. This result indicates that changes in sugarcane management systems could result in changes on the soil chemical properties, mostly, especially humification index of organic matter. It seems that in conversion from slash-and-burn to green harvest system, free water porosity turns to be an important aspect in order to explain part of FCO2 spatial variability in green managed system.

Analysis of the cost and efficiency relationship: experience in the Turkish pay for performance system.

PubMed

Gok, Mehmet Sahin; Altındağ, Erkut

2015-06-01

This paper analyzes the effects of the pay for performance (PFP) system on the efficiencies of public and private hospitals in Turkey. In order to evaluate these effects, we examine the relationship between hospital efficiency and health care costs in Turkey, and address the impact of the PFP system on the efficiencies of public and private hospitals. In an effort to analyze the efficiencies of public and private hospitals, this study uses data envelopment analysis. The Malmquist Productivity Index is also used to analyze the patterns of efficiency change for the study years from 2001 to 2008. This study shows that health care costs and hospital efficiency are negatively correlated for private hospitals, while they are positively correlated for public hospitals. In other words, increased health care costs might reduce efficiency in private hospitals in contrast to public hospitals. Our findings also indicate that average efficiencies of public hospitals tend to increase, particularly during the implementation period of PFP system. The efficiency trend of private hospitals, conversely, decreased in the latter periods of the PFP system. Suggestions for improvement are provided to the health care policy makers regarding the impact of health care reforms on public and private hospitals.

Seasonal Prediction of Taiwan's Streamflow Using Teleconnection Patterns

NASA Astrophysics Data System (ADS)

Chen, Chia-Jeng; Lee, Tsung-Yu

2017-04-01

Seasonal streamflow as an integrated response to complex hydro-climatic processes can be subject to activity of prevailing weather systems potentially modulated by large-scale climate oscillations (e.g., El Niño-Southern Oscillation, ENSO). To develop a seamless seasonal forecasting system in Taiwan, this study assesses how significant Taiwan's precipitation and streamflow in different seasons correlate with selected teleconnection patterns. Long-term precipitation and streamflow data in three major precipitation seasons, namely the spring rains (February to April), Mei-Yu (May and June), and typhoon (July to September) seasons, are derived at 28 upstream and 13 downstream catchments in Taiwan. The three seasons depict a complete wet period of Taiwan as well as many regions bearing similar climatic conditions in East Asia. Lagged correlation analysis is then performed to investigate how the precipitation and streamflow data correlate with predominant teleconnection indices at varied lead times. Teleconnection indices are selected only if they show certain linkage with weather systems and activity in the three seasons based on previous literature. For instance, the ENSO and Quasi-Biennial Oscillation, proven to influence East Asian climate across seasons and summer typhoon activity, respectively, are included in the list of climate indices for correlation analysis. Significant correlations found between Taiwan's precipitation and streamflow and teleconnection indices are further examined by a climate regime shift (CRS) test to identify any abrupt changes in the correlations. The understanding of existing CRS is useful for informing the forecasting system of the changes in the predictor-predictand relationship. To evaluate prediction skill in the three seasons and skill differences between precipitation and streamflow, hindcasting experiments of precipitation and streamflow are conducted using stepwise linear regression models. Discussion and suggestions for coping with extreme events in empirical seasonal predictions are also carried out. Findings from this work will contribute to the development of an integrated water resources planning and management system.

Torsional actuation with extension-torsion composite coupling and a magnetostrictive actuator

NASA Astrophysics Data System (ADS)

Bothwell, Christopher M.; Chandra, Ramesh; Chopra, Inderjit

1995-04-01

An analytical-experimental study of using magnetostrictive actuators in conjunction with an extension-torsion coupled composite tube to actuate a rotor blade trailing-edge flap to actively control helicopter vibration is presented. Thin walled beam analysis based on Vlasov theory was used to predict the induced twist and extension in a composite tube with magnetostrictive actuation. The study achieved good correlation between theory and experiment. The Kevlar-epoxy systems showed good correlation between measured and predicted twist values.

Laboratory studies of in vivo fluorescence of phytoplankton

NASA Technical Reports Server (NTRS)

Brown, C. A., Jr.; Farmer, F. H.; Jarrett, O., Jr.; Staton, W. L.

1978-01-01

A lidar system is developed that uses four selected excitation wavelengths to induce chlorophyll 'a' fluorescence which is indicative of both the concentration and diversity of phytoplankton. The operating principles of the system and the results of measurements of phytoplankton fluorescence in a controlled laboratory environment are presented. A comparative study of results from lidar fluorosensor laboratory tank tests using representative species of phytoplankton in single and multispecies cultures from each of four color groups reveals that (1) there is good correlation between the fluorescence of chlorophyll 'a' remotely simulated and detected by the lidar system and in-situ measurements using four similar excitation wavelengths in a flow-through fluorometer; (2) good correlation exists between the total chlorophyll 'a' calculated from lidar-fluorosensor data and measurements obtained by the Strickland-Parsons method; and (3) the lidar fluorosensor can provide an index of population diversity.

Numerical simulations of strongly correlated electron and spin systems

NASA Astrophysics Data System (ADS)

Changlani, Hitesh Jaiprakash

Developing analytical and numerical tools for strongly correlated systems is a central challenge for the condensed matter physics community. In the absence of exact solutions and controlled analytical approximations, numerical techniques have often contributed to our understanding of these systems. Exact Diagonalization (ED) requires the storage of at least two vectors the size of the Hilbert space under consideration (which grows exponentially with system size) which makes it affordable only for small systems. The Density Matrix Renormalization Group (DMRG) uses an intelligent Hilbert space truncation procedure to significantly reduce this cost, but in its present formulation is limited to quasi-1D systems. Quantum Monte Carlo (QMC) maps the Schrodinger equation to the diffusion equation (in imaginary time) and only samples the eigenvector over time, thereby avoiding the memory limitation. However, the stochasticity involved in the method gives rise to the "sign problem" characteristic of fermion and frustrated spin systems. The first part of this thesis is an effort to make progress in the development of a numerical technique which overcomes the above mentioned problems. We consider novel variational wavefunctions, christened "Correlator Product States" (CPS), that have a general functional form which hopes to capture essential correlations in the ground states of spin and fermion systems in any dimension. We also consider a recent proposal to modify projector (Green's Function) Quantum Monte Carlo to ameliorate the sign problem for realistic and model Hamiltonians (such as the Hubbard model). This exploration led to our own set of improvements, primarily a semistochastic formulation of projector Quantum Monte Carlo. Despite their limitations, existing numerical techniques can yield physical insights into a wide variety of problems. The second part of this thesis considers one such numerical technique - DMRG - and adapts it to study the Heisenberg antiferromagnet on a generic tree graph. Our attention turns to a systematic numerical and semi-analytical study of the effect of local even/odd sublattice imbalance on the low energy spectrum of antiferromagnets on regular Cayley trees. Finally, motivated by previous experiments and theories of randomly diluted antiferromagnets (where an even/odd sublattice imbalance naturally occurs), we present our study of the Heisenberg antiferromagnet on the Cayley tree at the percolation threshold. Our work shows how to detect "emergent" low energy degrees of freedom and compute the effective interactions between them by using data from DMRG calculations.

Cost study of solar cell space power systems.

NASA Technical Reports Server (NTRS)

Bernatowicz, D. T.

1972-01-01

A study of historical costs for solar cell space power systems was made by a NASA ad hoc study group. The study covered thirteen missions that represented a broad cross-section of flight projects over the past decade. Fully burdened costs in terms of 1971 dollars are presented for the system and the solar array. The costs correlate reasonably well with array area and do not increase in proportion to array area. The trends for array costs support the contention that solar cell and module standardization would reduce costs.

Water conservation study. Badger Army Ammunition Plant, Baraboo, Wisconsin. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1995-05-01

The purpose of this water conservation study is to identify projects which result in energy maintenance and cost savings in the process water distribution system at Badger Army Ammunition Plant (BAAP) in Baraboo, Wisconsin. A leak detection survey was performed on all process water piping with a diameter of 6 inches or greater. The leak detection analysis was performed using a combination of listening devices and preamplified-transducer systems to identify the majority of leak locations. When the location of the leak could not be readily identified using these methods, a leak correlator was used. The leak correlator determines leak locationmore » based on the time it takes for sound to travel from the leak to a waterline connection point.« less

Comparison between electromagnetic transponders and radiographic imaging for prostate localization: A pelvic phantom study with rotations and translations.

PubMed

Hamilton, Daniel G; McKenzie, Dean P; Perkins, Anne E

2017-09-01

The aim of this study was to evaluate the differences in target localization between Calypso ® , kV orthogonal imaging and cone-beam computed tomography (CBCT) for combined translations and rotations of an anthropomorphic pelvic phantom. The phantom was localized using all three systems in 50 different positions, with applied translational and rotational offsets randomly sampled from representative normal distributions of prostate motion. Lin's concordance correlation coefficient (ρc) and 95% confidence intervals were calculated to assess the agreement between the localization systems. Mean differences and difference vectors between the three systems were also calculated. Agreement between systems for lateral, vertical, and longitudinal translations was excellent, with ρc values of greater than 0.98 between all three systems in all axes. There was excellent agreement between the systems for rotations around the lateral axis (pitch) (ρc > 0.99), and around the vertical axis (yaw) (ρc > 0.97). However, somewhat poorer agreement for rotations around the longitudinal axis (roll) was observed, with the lowest correlation observed between Calypso and kV orthogonal imaging (ρc = 0.895). Mean differences between the phantom position reported by Calypso and the radiographic systems were less than 1 mm and 1° for all translations and rotations. The results for translations are consistent with the publications of previous authors. There is no comparable published data for rotations. While there is lower correlation between the three systems for roll than for the other angles, the mean differences in reported rotations are not clinically significant. © 2017 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

Measuring joint kinematics of treadmill walking and running: Comparison between an inertial sensor based system and a camera-based system.

PubMed

Nüesch, Corina; Roos, Elena; Pagenstert, Geert; Mündermann, Annegret

2017-05-24

Inertial sensor systems are becoming increasingly popular for gait analysis because their use is simple and time efficient. This study aimed to compare joint kinematics measured by the inertial sensor system RehaGait® with those of an optoelectronic system (Vicon®) for treadmill walking and running. Additionally, the test re-test repeatability of kinematic waveforms and discrete parameters for the RehaGait® was investigated. Twenty healthy runners participated in this study. Inertial sensors and reflective markers (PlugIn Gait) were attached according to respective guidelines. The two systems were started manually at the same time. Twenty consecutive strides for walking and running were recorded and each software calculated sagittal plane ankle, knee and hip kinematics. Measurements were repeated after 20min. Ensemble means were analyzed calculating coefficients of multiple correlation for waveforms and root mean square errors (RMSE) for waveforms and discrete parameters. After correcting the offset between waveforms, the two systems/models showed good agreement with coefficients of multiple correlation above 0.950 for walking and running. RMSE of the waveforms were below 5° for walking and below 8° for running. RMSE for ranges of motion were between 4° and 9° for walking and running. Repeatability analysis of waveforms showed very good to excellent coefficients of multiple correlation (>0.937) and RMSE of 3° for walking and 3-7° for running. These results indicate that in healthy subjects sagittal plane joint kinematics measured with the RehaGait® are comparable to those using a Vicon® system/model and that the measured kinematics have a good repeatability, especially for walking. Copyright © 2017 Elsevier Ltd. All rights reserved.

Message frames interact with motivational systems to determine depth of message processing.

PubMed

Shen, Lijiang; Dillard, James Price

2009-09-01

Although several theoretical perspectives predict that negatively framed messages will be processed more deeply than positively framed messages, a recent meta-analysis found no such difference. In this article, the authors explore 2 explanations for this inconsistency. One possibility is methodological: the statistics used in the primary studies underestimated framing effects on depth of message processing because the data were maldistributed. The other is theoretical: the absence of a main effect is veridical, but framing interacts with individual differences that predispose individuals to greater or lesser depth of processing. Data from 2 experiments (Ns = 286 and 252) were analyzed via tobit regression, a technique designed to overcome the limitations of maldistributed data. One study showed the predicted main effect for framing, but the other did not. Both studies showed the anticipated interaction: Depth of processing correlated positively with a measure of the behavioral activation system in the advantage framing condition, whereas depth of processing correlated positively with the behavioral inhibition system in the disadvantage framing condition.

Consistency properties of chaotic systems driven by time-delayed feedback

NASA Astrophysics Data System (ADS)

Jüngling, T.; Soriano, M. C.; Oliver, N.; Porte, X.; Fischer, I.

2018-04-01

Consistency refers to the property of an externally driven dynamical system to respond in similar ways to similar inputs. In a delay system, the delayed feedback can be considered as an external drive to the undelayed subsystem. We analyze the degree of consistency in a generic chaotic system with delayed feedback by means of the auxiliary system approach. In this scheme an identical copy of the nonlinear node is driven by exactly the same signal as the original, allowing us to verify complete consistency via complete synchronization. In the past, the phenomenon of synchronization in delay-coupled chaotic systems has been widely studied using correlation functions. Here, we analytically derive relationships between characteristic signatures of the correlation functions in such systems and unequivocally relate them to the degree of consistency. The analytical framework is illustrated and supported by numerical calculations of the logistic map with delayed feedback for different replica configurations. We further apply the formalism to time series from an experiment based on a semiconductor laser with a double fiber-optical feedback loop. The experiment constitutes a high-quality replica scheme for studying consistency of the delay-driven laser and confirms the general theoretical results.

Photon correlation in single-photon frequency upconversion.

PubMed

Gu, Xiaorong; Huang, Kun; Pan, Haifeng; Wu, E; Zeng, Heping

2012-01-30

We experimentally investigated the intensity cross-correlation between the upconverted photons and the unconverted photons in the single-photon frequency upconversion process with multi-longitudinal mode pump and signal sources. In theoretical analysis, with this multi-longitudinal mode of both signal and pump sources system, the properties of the signal photons could also be maintained as in the single-mode frequency upconversion system. Experimentally, based on the conversion efficiency of 80.5%, the joint probability of simultaneously detecting at upconverted and unconverted photons showed an anti-correlation as a function of conversion efficiency which indicated the upconverted photons were one-to-one from the signal photons. While due to the coherent state of the signal photons, the intensity cross-correlation function g(2)(0) was shown to be equal to unity at any conversion efficiency, agreeing with the theoretical prediction. This study will benefit the high-speed wavelength-tunable quantum state translation or photonic quantum interface together with the mature frequency tuning or longitudinal mode selection techniques.

Role of the Pair Correlation Function in the Dynamical Transition Predicted by Mode Coupling Theory.

PubMed

Nandi, Manoj Kumar; Banerjee, Atreyee; Dasgupta, Chandan; Bhattacharyya, Sarika Maitra

2017-12-29

In a recent study, we have found that for a large number of systems the configurational entropy at the pair level S_{c2}, which is primarily determined by the pair correlation function, vanishes at the dynamical transition temperature T_{c}. Thus, it appears that the information of the transition temperature is embedded in the structure of the liquid. In order to investigate this, we describe the dynamics of the system at the mean field level and, using the concepts of the dynamical density functional theory, show that the dynamical transition temperature depends only on the pair correlation function. Thus, this theory is similar in spirit to the microscopic mode coupling theory (MCT). However, unlike microscopic MCT, which predicts a very high transition temperature, the present theory predicts a transition temperature that is similar to T_{c}. This implies that the information of the dynamical transition temperature is embedded in the pair correlation function.

Correlation of pelvic organ prolapse quantification system scores with obstetric parameters and lower urinary tract symptoms in primiparae postpartum.

PubMed

Liang, Ching-Chung; Tseng, Ling-Hong; Horng, Shang-Gwo; Lin, I-wen; Chang, Shuenn-Dhy

2007-05-01

This study investigated the correlation between results of the pelvic organ prolapse quantification (POPQ) system at 3 days and at 2 months postpartum with obstetric parameters and lower urinary tract symptoms (LUTS) in 125 primiparae with vaginal delivery. The clinical characteristics, prevalence of pregnancy-related LUTS, and POPQ scores were evaluated. Regarding the relationship of obstetric parameters with POPQ scoring, the gh was found positively correlated with the body mass index and vaginal laceration at 2 months postpartum. The POPQ evaluation did not find the LUTS to be significantly related to the prolapse score. The mean scores of points C and D were significantly increased, and gh, pb, and tvl were significantly decreased between the initial and 2-month follow-up scores. Our results revealed that a decrease in vaginal size is the principal change during the first 2 months postpartum and that with the exception of gh, neither the obstetric parameters nor the LUTS were associated with the POPQ scoring system.