DEFF Research Database (Denmark)
Kovács, Gábor G; Gelpi, Ellen; Ströbel, Thomas
2007-01-01
The endosomal-lysosomal system (ELS) has been suggested to play a role in the pathogenesis of prion diseases. The purpose of this study was to examine how experimental observations can be translated to human neuropathology and whether alterations of the ELS relate to neuropathologic changes...... correlate with regional pathology. Overloading of this system might impair the function of lysosomal enzymes and thus may mimic some features of lysosomal storage disorders. Udgivelsesdato: 2007-Jul...
Directory of Open Access Journals (Sweden)
Craig D Blanchette
Full Text Available BACKGROUND: Phagocytosis has been extensively examined in 'professional' phagocytic cells using pH sensitive dyes. However, in many of the previous studies, a separation between the end of internalization, beginning of acidification and completion of phagosomal-endosomal/lysosomal fusion was not clearly established. In addition, very little work has been done to systematically examine phagosomal maturation in 'non-professional' phagocytic cells. Therefore, in this study, we developed a simple method to measure and decouple particle internalization, phagosomal acidification and phagosomal-endosomal/lysosomal fusion in Madin-Darby Canine Kidney (MDCK and Caco-2 epithelial cells. METHODOLOGY/PRINCIPAL FINDINGS: Our method was developed using a pathogen mimetic system consisting of polystyrene beads coated with Internalin A (InlA, a membrane surface protein from Listeria monocytogenes known to trigger receptor-mediated phagocytosis. We were able to independently measure the rates of internalization, phagosomal acidification and phagosomal-endosomal/lysosomal fusion in epithelial cells by combining the InlA-coated beads (InlA-beads with antibody quenching, a pH sensitive dye and an endosomal/lysosomal dye. By performing these independent measurements under identical experimental conditions, we were able to decouple the three processes and establish time scales for each. In a separate set of experiments, we exploited the phagosomal acidification process to demonstrate an additional, real-time method for tracking bead binding, internalization and phagosomal acidification. CONCLUSIONS/SIGNIFICANCE: Using this method, we found that the time scales for internalization, phagosomal acidification and phagosomal-endosomal/lysosomal fusion ranged from 23-32 min, 3-4 min and 74-120 min, respectively, for MDCK and Caco-2 epithelial cells. Both the static and real-time methods developed here are expected to be readily and broadly applicable, as they simply
The late endosome/lysosome-anchored p18-mTORC1 pathway controls terminal maturation of lysosomes
Energy Technology Data Exchange (ETDEWEB)
Takahashi, Yusuke; Nada, Shigeyuki; Mori, Shunsuke; Soma-Nagae, Taeko; Oneyama, Chitose [Department of Oncogene Research, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Okada, Masato, E-mail: okadam@biken.osaka-u.ac.jp [Department of Oncogene Research, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)
2012-01-27
Highlights: Black-Right-Pointing-Pointer p18 is a membrane adaptor that anchors mTORC1 to late endosomes/lysosomes. Black-Right-Pointing-Pointer We examine the role of the p18-mTORC1 pathway in lysosome biogenesis. Black-Right-Pointing-Pointer The loss of p18 causes accumulation of intact late endosomes by arresting lysosome maturation. Black-Right-Pointing-Pointer Inhibition of mTORC1 activity with rapamycin phenocopies the defects of p18 loss. Black-Right-Pointing-Pointer The p18-mTORC1 pathway plays crucial roles in the terminal maturation of lysosomes. -- Abstract: The late endosome/lysosome membrane adaptor p18 (or LAMTOR1) serves as an anchor for the mammalian target of rapamycin complex 1 (mTORC1) and is required for its activation on lysosomes. The loss of p18 causes severe defects in cell growth as well as endosome dynamics, including membrane protein transport and lysosome biogenesis. However, the mechanisms underlying these effects on lysosome biogenesis remain unknown. Here, we show that the p18-mTORC1 pathway is crucial for terminal maturation of lysosomes. The loss of p18 causes aberrant intracellular distribution and abnormal sizes of late endosomes/lysosomes and an accumulation of late endosome specific components, including Rab7, RagC, and LAMP1; this suggests that intact late endosomes accumulate in the absence of p18. These defects are phenocopied by inhibiting mTORC1 activity with rapamycin. Loss of p18 also suppresses the integration of late endosomes and lysosomes, resulting in the defective degradation of tracer proteins. These results suggest that the p18-mTORC1 pathway plays crucial roles in the late stages of lysosomal maturation, potentially in late endosome-lysosome fusion, which is required for processing of various macromolecules.
Canfrán-Duque, Alberto; Barrio, Luis C; Lerma, Milagros; de la Peña, Gema; Serna, Jorge; Pastor, Oscar; Lasunción, Miguel A; Busto, Rebeca
2016-03-18
First- and second-generation antipsychotics (FGAs and SGAs, respectively), have the ability to inhibit cholesterol biosynthesis and also to interrupt the intracellular cholesterol trafficking, interfering with low-density lipoprotein (LDL)-derived cholesterol egress from late endosomes/lysosomes. In the present work, we examined the effects of FGA haloperidol on the functionality of late endosomes/lysosomes in vitro. In HepG2 hepatocarcinoma cells incubated in the presence of 1,1'-dioctadecyl-3,3,3,3'-tetramethylindocarbocyanineperchlorate (DiI)-LDL, treatment with haloperidol caused the enlargement of organelles positive for late endosome markers lysosome-associated membrane protein 2 (LAMP-2) and LBPA (lysobisphosphatidic acid), which also showed increased content of both free-cholesterol and DiI derived from LDL. This indicates the accumulation of LDL-lipids in the late endosomal/lysosomal compartment caused by haloperidol. In contrast, LDL traffic through early endosomes and the Golgi apparatus appeared to be unaffected by the antipsychotic as the distribution of both early endosome antigen 1 (EEA1) and coatomer subunit β (β-COP) were not perturbed. Notably, treatment with haloperidol significantly increased the lysosomal pH and decreased the activities of lysosomal protease and β-d-galactosidase in a dose-dependent manner. We conclude that the alkalinization of the lysosomes' internal milieu induced by haloperidol affects lysosomal functionality.
Directory of Open Access Journals (Sweden)
Alberto Canfrán-Duque
2016-03-01
Full Text Available First- and second-generation antipsychotics (FGAs and SGAs, respectively, have the ability to inhibit cholesterol biosynthesis and also to interrupt the intracellular cholesterol trafficking, interfering with low-density lipoprotein (LDL-derived cholesterol egress from late endosomes/lysosomes. In the present work, we examined the effects of FGA haloperidol on the functionality of late endosomes/lysosomes in vitro. In HepG2 hepatocarcinoma cells incubated in the presence of 1,1′-dioctadecyl-3,3,3,3′-tetramethylindocarbocyanineperchlorate (DiI-LDL, treatment with haloperidol caused the enlargement of organelles positive for late endosome markers lysosome-associated membrane protein 2 (LAMP-2 and LBPA (lysobisphosphatidic acid, which also showed increased content of both free-cholesterol and DiI derived from LDL. This indicates the accumulation of LDL-lipids in the late endosomal/lysosomal compartment caused by haloperidol. In contrast, LDL traffic through early endosomes and the Golgi apparatus appeared to be unaffected by the antipsychotic as the distribution of both early endosome antigen 1 (EEA1 and coatomer subunit β (β-COP were not perturbed. Notably, treatment with haloperidol significantly increased the lysosomal pH and decreased the activities of lysosomal protease and β-d-galactosidase in a dose-dependent manner. We conclude that the alkalinization of the lysosomes’ internal milieu induced by haloperidol affects lysosomal functionality.
Mundy, Dorothy I.; Li, Wei Ping; Luby-Phelps, Katherine; Anderson, Richard G. W.
2012-01-01
Caveolin-1 is an integral membrane protein of plasma membrane caveolae. Here we report that caveolin-1 collects at the cytosolic surface of lysosomal membranes when cells are serum starved. This is due to an elevation of the intralysosomal pH, since ionophores and proton pump inhibitors that dissipate the lysosomal pH gradient also trapped caveolin-1 on late endosome/lysosomes. Accumulation is both saturable and reversible. At least a portion of the caveolin-1 goes to the plasma membrane upon reversal. Several studies suggest that caveolin-1 is involved in cholesterol transport within the cell. Strikingly, we find that blocking cholesterol export from lysosomes with progesterone or U18666A or treating cells with low concentrations of cyclodextrin also caused caveolin-1 to accumulate on late endosome/lysosomal membranes. Under these conditions, however, live-cell imaging shows cavicles actively docking with lysosomes, suggesting that these structures might be involved in delivering caveolin-1. Targeting of caveolin-1 to late endosome/lysosomes is not observed normally, and the degradation rate of caveolin-1 is not altered by any of these conditions, indicating that caveolin-1 accumulation is not a consequence of blocked degradation. We conclude that caveolin-1 normally traffics to and from the cytoplasmic surface of lysosomes during intracellular cholesterol trafficking. PMID:22238363
Canfrán-Duque, Alberto; Barrio, Luis C.; Lerma, Milagros; de la Peña, Gema; Serna, Jorge; Pastor, Oscar; Lasunción, Miguel A.; Busto, Rebeca
2016-01-01
First- and second-generation antipsychotics (FGAs and SGAs, respectively), have the ability to inhibit cholesterol biosynthesis and also to interrupt the intracellular cholesterol trafficking, interfering with low-density lipoprotein (LDL)-derived cholesterol egress from late endosomes/lysosomes. In the present work, we examined the effects of FGA haloperidol on the functionality of late endosomes/lysosomes in vitro. In HepG2 hepatocarcinoma cells incubated in the presence of 1,1′-dioctadecyl-3,3,3,3′-tetramethylindocarbocyanineperchlorate (DiI)-LDL, treatment with haloperidol caused the enlargement of organelles positive for late endosome markers lysosome-associated membrane protein 2 (LAMP-2) and LBPA (lysobisphosphatidic acid), which also showed increased content of both free-cholesterol and DiI derived from LDL. This indicates the accumulation of LDL-lipids in the late endosomal/lysosomal compartment caused by haloperidol. In contrast, LDL traffic through early endosomes and the Golgi apparatus appeared to be unaffected by the antipsychotic as the distribution of both early endosome antigen 1 (EEA1) and coatomer subunit β (β-COP) were not perturbed. Notably, treatment with haloperidol significantly increased the lysosomal pH and decreased the activities of lysosomal protease and β-d-galactosidase in a dose-dependent manner. We conclude that the alkalinization of the lysosomes’ internal milieu induced by haloperidol affects lysosomal functionality. PMID:26999125
The late endosome/lysosome-anchored p18-mTORC1 pathway controls terminal maturation of lysosomes
International Nuclear Information System (INIS)
Takahashi, Yusuke; Nada, Shigeyuki; Mori, Shunsuke; Soma-Nagae, Taeko; Oneyama, Chitose; Okada, Masato
2012-01-01
Highlights: ► p18 is a membrane adaptor that anchors mTORC1 to late endosomes/lysosomes. ► We examine the role of the p18-mTORC1 pathway in lysosome biogenesis. ► The loss of p18 causes accumulation of intact late endosomes by arresting lysosome maturation. ► Inhibition of mTORC1 activity with rapamycin phenocopies the defects of p18 loss. ► The p18-mTORC1 pathway plays crucial roles in the terminal maturation of lysosomes. -- Abstract: The late endosome/lysosome membrane adaptor p18 (or LAMTOR1) serves as an anchor for the mammalian target of rapamycin complex 1 (mTORC1) and is required for its activation on lysosomes. The loss of p18 causes severe defects in cell growth as well as endosome dynamics, including membrane protein transport and lysosome biogenesis. However, the mechanisms underlying these effects on lysosome biogenesis remain unknown. Here, we show that the p18-mTORC1 pathway is crucial for terminal maturation of lysosomes. The loss of p18 causes aberrant intracellular distribution and abnormal sizes of late endosomes/lysosomes and an accumulation of late endosome specific components, including Rab7, RagC, and LAMP1; this suggests that intact late endosomes accumulate in the absence of p18. These defects are phenocopied by inhibiting mTORC1 activity with rapamycin. Loss of p18 also suppresses the integration of late endosomes and lysosomes, resulting in the defective degradation of tracer proteins. These results suggest that the p18-mTORC1 pathway plays crucial roles in the late stages of lysosomal maturation, potentially in late endosome–lysosome fusion, which is required for processing of various macromolecules.
Nixon, Ralph A
2017-07-01
Abnormalities of the endosomal-lysosomal network (ELN) are a signature feature of Alzheimer's disease (AD). These include the earliest known cytopathology that is specific to AD and that affects endosomes and induces the progressive failure of lysosomes, each of which are directly linked by distinct mechanisms to neurodegeneration. The origins of ELN dysfunction and β-amyloidogenesis closely overlap, which reflects their common genetic basis, the established early involvement of endosomes and lysosomes in amyloid precursor protein (APP) processing and clearance, and the pathologic effect of certain APP metabolites on ELN functions. Genes that promote β-amyloidogenesis in AD (APP, PSEN1/2, and APOE4) have primary effects on ELN function. The importance of primary ELN dysfunction to pathogenesis is underscored by the mutations in more than 35 ELN-related genes that, thus far, are known to cause familial neurodegenerative diseases even though different pathogenic proteins may be involved. In this article, I discuss growing evidence that implicates AD gene-driven ELN disruptions as not only the antecedent pathobiology that underlies β-amyloidogenesis but also as the essential partner with APP and its metabolites that drive the development of AD, including tauopathy, synaptic dysfunction, and neurodegeneration. The striking amelioration of diverse deficits in animal AD models by remediating ELN dysfunction further supports a need to integrate APP and ELN relationships, including the role of amyloid-β, into a broader conceptual framework of how AD arises, progresses, and may be effectively therapeutically targeted.-Nixon, R. A. Amyloid precursor protein and endosomal-lysosomal dysfunction in Alzheimer's disease: inseparable partners in a multifactorial disease. © FASEB.
Wang, Zheng; Miao, Guangyan; Xue, Xue; Guo, Xiangyang; Yuan, Chongzhen; Wang, Zhaoyu; Zhang, Gangming; Chen, Yingyu; Feng, Du; Hu, Junjie; Zhang, Hong
2016-09-01
Mutations in the human autophagy gene EPG5 cause the multisystem disorder Vici syndrome. Here we demonstrated that EPG5 is a Rab7 effector that determines the fusion specificity of autophagosomes with late endosomes/lysosomes. EPG5 is recruited to late endosomes/lysosomes by direct interaction with Rab7 and the late endosomal/lysosomal R-SNARE VAMP7/8. EPG5 also binds to LC3/LGG-1 (mammalian and C. elegans Atg8 homolog, respectively) and to assembled STX17-SNAP29 Qabc SNARE complexes on autophagosomes. EPG5 stabilizes and facilitates the assembly of STX17-SNAP29-VAMP7/8 trans-SNARE complexes, and promotes STX17-SNAP29-VAMP7-mediated fusion of reconstituted proteoliposomes. Loss of EPG5 activity causes abnormal fusion of autophagosomes with various endocytic vesicles, in part due to elevated assembly of STX17-SNAP25-VAMP8 complexes. SNAP25 knockdown partially suppresses the autophagy defect caused by EPG5 depletion. Our study reveals that EPG5 is a Rab7 effector involved in autophagosome maturation, providing insight into the molecular mechanism underlying Vici syndrome. Copyright © 2016 Elsevier Inc. All rights reserved.
Kaufmann, A M; Goldman, S D B; Krise, J P
2009-03-01
Traditionally, lysosomes have been considered to be a terminal endocytic compartment. Recent studies suggest that lysosomes are quite dynamic, being able to fuse with other late endocytic compartments as well as with the plasma membrane. Here we describe a quantitative fluorescence energy transfer (FRET)-based method for assessing rates of retrograde fusion between terminal lysosomes and late endosomes in living cells. Late endosomes were specifically labeled with 800-nm latex beads that were conjugated with streptavidin and Alexa Fluor 555 (FRET donor). Terminal lysosomes were specifically labeled with 10,000-MW dextran polymers conjugated with biotin and Alexa Fluor 647 (FRET acceptor). Following late endosome-lysosome fusion, the strong binding affinity between streptavidin and biotin brought the donor and acceptor fluorophore molecules into close proximity, thereby facilitating the appearance of a FRET emission signal. Because apparent size restrictions in the endocytic pathway do not permit endocytosed latex beads from reaching terminal lysosomes in an anterograde fashion, the appearance of the FRET signal is consistent with retrograde transport of lysosomal cargo back to late endosomes. We assessed the efficiency of this transport step in fibroblasts affected by different lysosome storage disorders-Niemann-Pick type C, mucolipidosis type IV, and Sandhoff's disease, all of which have a similar lysosomal lipid accumulation phenotype. We report here, for the first time, that these disorders can be distinguished by their rate of transfer of lysosome cargos to late endosomes, and we discuss the implications of these findings for developing new therapeutic strategies.
Yin, Kaifeng; Lin, Wenting; Guo, Jing; Sugiyama, Toshihiro; Snead, Malcolm L; Hacia, Joseph G; Paine, Michael L
2017-03-13
Amelogenesis imperfecta (AI) is group of inherited disorders resulting in enamel pathologies. The involvement of epigenetic regulation in the pathogenesis of AI is yet to be clarified due to a lack of knowledge about amelogenesis. Our previous genome-wide microRNA and mRNA transcriptome analyses suggest a key role for miR-153 in endosome/lysosome-related pathways during amelogenesis. Here we show that miR-153 is significantly downregulated in maturation ameloblasts compared with secretory ameloblasts. Within ameloblast-like cells, upregulation of miR-153 results in the downregulation of its predicted targets including Cltc, Lamp1, Clcn4 and Slc4a4, and a number of miRNAs implicated in endocytotic pathways. Luciferase reporter assays confirmed the predicted interactions between miR-153 and the 3'-UTRs of Cltc, Lamp1 (in a prior study), Clcn4 and Slc4a4. In an enamel protein intake assay, enamel cells transfected with miR-153 show a decreased ability to endocytose enamel proteins. Finally, microinjection of miR-153 in the region of mouse first mandibular molar at postnatal day 8 (PN8) induced AI-like pathologies when the enamel development reached maturity (PN12). In conclusion, miR-153 regulates maturation-stage amelogenesis by targeting key genes involved in the endocytotic and endosomal/lysosomal pathways, and disruption of miR-153 expression is a potential candidate etiologic factor contributing to the occurrence of AI.
Yin, Kaifeng; Lin, Wenting; Guo, Jing; Sugiyama, Toshihiro; Snead, Malcolm L.; Hacia, Joseph G.; Paine, Michael L.
2017-01-01
Amelogenesis imperfecta (AI) is group of inherited disorders resulting in enamel pathologies. The involvement of epigenetic regulation in the pathogenesis of AI is yet to be clarified due to a lack of knowledge about amelogenesis. Our previous genome-wide microRNA and mRNA transcriptome analyses suggest a key role for miR-153 in endosome/lysosome-related pathways during amelogenesis. Here we show that miR-153 is significantly downregulated in maturation ameloblasts compared with secretory ameloblasts. Within ameloblast-like cells, upregulation of miR-153 results in the downregulation of its predicted targets including Cltc, Lamp1, Clcn4 and Slc4a4, and a number of miRNAs implicated in endocytotic pathways. Luciferase reporter assays confirmed the predicted interactions between miR-153 and the 3′-UTRs of Cltc, Lamp1 (in a prior study), Clcn4 and Slc4a4. In an enamel protein intake assay, enamel cells transfected with miR-153 show a decreased ability to endocytose enamel proteins. Finally, microinjection of miR-153 in the region of mouse first mandibular molar at postnatal day 8 (PN8) induced AI-like pathologies when the enamel development reached maturity (PN12). In conclusion, miR-153 regulates maturation-stage amelogenesis by targeting key genes involved in the endocytotic and endosomal/lysosomal pathways, and disruption of miR-153 expression is a potential candidate etiologic factor contributing to the occurrence of AI. PMID:28287144
Directory of Open Access Journals (Sweden)
Xiang B
2017-03-01
Full Text Available Bai Xiang,1,* Xue-Li Jia,1,* Jin-Long Qi,2 Li-Ping Yang,1 Wei-Hong Sun,1 Xiao Yan,1 Shao-Kun Yang,1 De-Ying Cao,1 Qing Du,1 Xian-Rong Qi3 1Department of Pharmaceutics, School of Pharmaceutical Sciences, 2Department of Pharmacology, Hebei Medical University, Shijiazhuang, Hebei, 3School of Pharmaceutical Sciences, Peking University, Beijing, China *These authors contributed equally to this work Abstract: As a potent therapeutic agent, small interfering RNA (siRNA has been exploited to silence critical genes involved in tumor initiation and progression. However, development of a desirable delivery system is required to overcome the unfavorable properties of siRNA such as its high degradability, molecular size, and negative charge to help increase its accumulation in tumor tissues and promote efficient cellular uptake and endosomal/lysosomal escape of the nucleic acids. In this study, we developed a new activatable cell-penetrating peptide (ACPP that is responsive to an acidic tumor microenvironment, which was then used to modify the surfaces of siRNA-loaded liposomes. The ACPP is composed of a cell-penetrating peptide (CPP, an acid-labile linker (hydrazone, and a polyanionic domain, including glutamic acid and histidine. In the systemic circulation (pH 7.4, the surface polycationic moieties of the CPP (polyarginine are “shielded” by the intramolecular electrostatic interaction of the inhibitory domain. When exposed to a lower pH, a common property of solid tumors, the ACPP undergoes acid-catalyzed breakage at the hydrazone site, and the consequent protonation of histidine residues promotes detachment of the inhibitory peptide. Subsequently, the unshielded CPP would facilitate the cellular membrane penetration and efficient endosomal/lysosomal evasion of liposomal siRNA. A series of investigations demonstrated that once exposed to an acidic pH, the ACPP-modified liposomes showed elevated cellular uptake, downregulated expression of polo
Correlations in charged bosons systems
International Nuclear Information System (INIS)
Almeida Caparica, A. de.
1985-02-01
The two and three-dimensional charge Bose gas have been studied. In the bidimensional case two different types of interaction were considered: l/r and l n(r). The method of self-consistent-field was applied to these systems, which takes into account the short range correlations between the bosons through a local-field correction. By using self-consistent numerical calculations, the structure factor S(k → ) was determined. The pair-correlation function, the ground-state energy, the pressure of the gas and the spectrum of elementary excitations were obtained from S (k → ). The screening density induced by a fixed charged impurity was calculated. In the high-density limit our calculations reproduce the results given by Bogoliubov's perturbation theory. In the intermediate-density region, corresponding to the strongly coupled systems, the results are in very good agreement with calculations based on HNC approximation as well as Monte Carlo method. The results are compared in several situations with RPA results showing that the self-consistent method is much more accurate. The two-dimensional systems showed to be more correlated than the three-dimensional systems showed to be more correlated than the three-dimensional one; the gas with interaction l/r is also more correlated than the logarithmic one at high densities, but it begins to be less correlated than this one in the low-density region. The thermodynamic functions of the two and three-dimensional systems at finite temperatures near absolute zero are calculated based upon the gas excitation spectra at zero temperature. (author)
Strongly correlated systems experimental techniques
Mancini, Ferdinando
2015-01-01
The continuous evolution and development of experimental techniques is at the basis of any fundamental achievement in modern physics. Strongly correlated systems (SCS), more than any other, need to be investigated through the greatest variety of experimental techniques in order to unveil and crosscheck the numerous and puzzling anomalous behaviors characterizing them. The study of SCS fostered the improvement of many old experimental techniques, but also the advent of many new ones just invented in order to analyze the complex behaviors of these systems. Many novel materials, with functional properties emerging from macroscopic quantum behaviors at the frontier of modern research in physics, chemistry and materials science, belong to this class of systems. The volume presents a representative collection of the modern experimental techniques specifically tailored for the analysis of strongly correlated systems. Any technique is presented in great detail by its own inventor or by one of the world-wide recognize...
Peng, Yixing; Yao, Wenjun; Wang, Bo; Zong, Li
2015-04-01
Gene transfer mediated by mannosylated chitosan (MCS) is a safe and promising approach for gene and vaccine delivery. MCS nanoparticles based gene delivery system showed high in vivo delivery efficiency and elicited strong immune responses in mice. However, little knowledge about the cell binding, transfection efficiency and intracellular trafficking of MCS nanoparticles had been acquired. In this study, using gastrin-releasing peptide as a model plasmid (pGRP), the binding of MCS/pGRP nanoparticles to macrophages and the intracellular trafficking of MCS/pGRP nanoparticles in macrophages were investigated. MCS-mediated transfection efficiency in macrophages was also evaluated using pGL-3 as a reporter gene. The results showed that the binding and transfection efficiency of MCS nanoparticles in macrophages was higher than that of CS, which was attributed to the interaction between mannose ligands in MCS and mannose receptors on the surface of macrophages. Observation with a confocal laser scanning microscope indicated the cellular uptake of MCS/pGRP nanoparticles were more than that of CS/pGRP nanoparticles in macrophages. MCS/pGRP nanoparticles were taken up by macrophages and most of them were entrapped in endosomal/lysosomal compartments. After the nanoparticles escaping from endosomal/lysosomal compartments, naked pGRP entered the nucleus, and a few MCS might enter the nucleus in terms of nanoparticles. Overall, MCS has the potential to be an excellent macrophage-targeting gene delivery carrier.
Strongly Correlated Systems Theoretical Methods
Avella, Adolfo
2012-01-01
The volume presents, for the very first time, an exhaustive collection of those modern theoretical methods specifically tailored for the analysis of Strongly Correlated Systems. Many novel materials, with functional properties emerging from macroscopic quantum behaviors at the frontier of modern research in physics, chemistry and materials science, belong to this class of systems. Any technique is presented in great detail by its own inventor or by one of the world-wide recognized main contributors. The exposition has a clear pedagogical cut and fully reports on the most relevant case study where the specific technique showed to be very successful in describing and enlightening the puzzling physics of a particular strongly correlated system. The book is intended for advanced graduate students and post-docs in the field as textbook and/or main reference, but also for other researchers in the field who appreciates consulting a single, but comprehensive, source or wishes to get acquainted, in a as painless as po...
Strongly correlated systems numerical methods
Mancini, Ferdinando
2013-01-01
This volume presents, for the very first time, an exhaustive collection of those modern numerical methods specifically tailored for the analysis of Strongly Correlated Systems. Many novel materials, with functional properties emerging from macroscopic quantum behaviors at the frontier of modern research in physics, chemistry and material science, belong to this class of systems. Any technique is presented in great detail by its own inventor or by one of the world-wide recognized main contributors. The exposition has a clear pedagogical cut and fully reports on the most relevant case study where the specific technique showed to be very successful in describing and enlightening the puzzling physics of a particular strongly correlated system. The book is intended for advanced graduate students and post-docs in the field as textbook and/or main reference, but also for other researchers in the field who appreciate consulting a single, but comprehensive, source or wishes to get acquainted, in a as painless as possi...
Echoes in correlated neural systems
International Nuclear Information System (INIS)
Helias, M; Tetzlaff, T; Diesmann, M
2013-01-01
Correlations are employed in modern physics to explain microscopic and macroscopic phenomena, like the fractional quantum Hall effect and the Mott insulator state in high temperature superconductors and ultracold atoms. Simultaneously probed neurons in the intact brain reveal correlations between their activity, an important measure to study information processing in the brain that also influences the macroscopic signals of neural activity, like the electroencephalogram (EEG). Networks of spiking neurons differ from most physical systems: the interaction between elements is directed, time delayed, mediated by short pulses and each neuron receives events from thousands of neurons. Even the stationary state of the network cannot be described by equilibrium statistical mechanics. Here we develop a quantitative theory of pairwise correlations in finite-sized random networks of spiking neurons. We derive explicit analytic expressions for the population-averaged cross correlation functions. Our theory explains why the intuitive mean field description fails, how the echo of single action potentials causes an apparent lag of inhibition with respect to excitation and how the size of the network can be scaled while maintaining its dynamical state. Finally, we derive a new criterion for the emergence of collective oscillations from the spectrum of the time-evolution propagator. (paper)
PREFACE: Strongly correlated electron systems Strongly correlated electron systems
Saxena, Siddharth S.; Littlewood, P. B.
2012-07-01
This special section is dedicated to the Strongly Correlated Electron Systems Conference (SCES) 2011, which was held from 29 August-3 September 2011, in Cambridge, UK. SCES'2011 is dedicated to 100 years of superconductivity and covers a range of topics in the area of strongly correlated systems. The correlated electronic and magnetic materials featured include f-electron based heavy fermion intermetallics and d-electron based transition metal compounds. The selected papers derived from invited presentations seek to deepen our understanding of the rich physical phenomena that arise from correlation effects. The focus is on quantum phase transitions, non-Fermi liquid phenomena, quantum magnetism, unconventional superconductivity and metal-insulator transitions. Both experimental and theoretical work is presented. Based on fundamental advances in the understanding of electronic materials, much of 20th century materials physics was driven by miniaturisation and integration in the electronics industry to the current generation of nanometre scale devices. The achievements of this industry have brought unprecedented advances to society and well-being, and no doubt there is much further to go—note that this progress is founded on investments and studies in the fundamentals of condensed matter physics from more than 50 years ago. Nevertheless, the defining challenges for the 21st century will lie in the discovery in science, and deployment through engineering, of technologies that can deliver the scale needed to have an impact on the sustainability agenda. Thus the big developments in nanotechnology may lie not in the pursuit of yet smaller transistors, but in the design of new structures that can revolutionise the performance of solar cells, batteries, fuel cells, light-weight structural materials, refrigeration, water purification, etc. The science presented in the papers of this special section also highlights the underlying interest in energy-dense materials, which
EDITORIAL: Strongly correlated electron systems Strongly correlated electron systems
Ronning, Filip; Batista, Cristian
2011-03-01
Strongly correlated electrons is an exciting and diverse field in condensed matter physics. This special issue aims to capture some of that excitement and recent developments in the field. Given that this issue was inspired by the 2010 International Conference on Strongly Correlated Electron Systems (SCES 2010), we briefly give some history in order to place this issue in context. The 2010 International Conference on Strongly Correlated Electron Systems was held in Santa Fe, New Mexico, a reunion of sorts from the 1989 International Conference on the Physics of Highly Correlated Electron Systems that also convened in Santa Fe. SCES 2010—co-chaired by John Sarrao and Joe Thompson—followed the tradition of earlier conferences, in this century, hosted by Buzios (2008), Houston (2007), Vienna (2005), Karlsruhe (2004), Krakow (2002) and Ann Arbor (2001). Every three years since 1997, SCES has joined the International Conference on Magnetism (ICM), held in Recife (2000), Rome (2003), Kyoto (2006) and Karlsruhe (2009). Like its predecessors, SCES 2010 topics included strongly correlated f- and d-electron systems, heavy-fermion behaviors, quantum-phase transitions, non-Fermi liquid phenomena, unconventional superconductivity, and emergent states that arise from electronic correlations. Recent developments from studies of quantum magnetism and cold atoms complemented the traditional subjects and were included in SCES 2010. 2010 celebrated the 400th anniversary of Santa Fe as well as the birth of astronomy. So what's the connection to SCES? The Dutch invention of the first practical telescope and its use by Galileo in 1610 and subsequent years overturned dogma that the sun revolved about the earth. This revolutionary, and at the time heretical, conclusion required innovative combinations of new instrumentation, observation and mathematics. These same combinations are just as important 400 years later and are the foundation of scientific discoveries that were discussed
Reliability of Structural Systems with Correlated Elements
DEFF Research Database (Denmark)
Thoft-Christensen, Palle; Sørensen, John Dalsgaard
1982-01-01
Calculation of the probability of failure of a system with correlation members is usually a difficult and time-consuming numerical problem. However, for some types of systems with equally correlated elements this calculation can be performed in a simple way. This has suggested two new methods bas...... on so-called average and equivalent correlation coefficients. By using these methods approximate values for the probability of failure can easily be calculated. The accuracy of these methods is illustrated with examples....
Quantum correlations in multipartite quantum systems
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.
Universal behavior of strongly correlated Fermi systems
Energy Technology Data Exchange (ETDEWEB)
Shaginyan, Vasilii R [B.P. Konstantinov St. Petersburg Institute of Nuclear Physics, Russian Academy of Sciences, Gatchina, Leningrad region, Rusian Federation (Russian Federation); Amusia, M Ya [A.F. Ioffe Physico-Technical Institute, Russian Academy of Sciences, St. Petersburg (Russian Federation); Popov, Konstantin G [Komi Scientific Center, Ural Branch of the Russian Academy of Sciences, Syktyvkar (Russian Federation)
2007-06-30
This review discusses the construction of a theory and the analysis of phenomena occurring in strongly correlated Fermi systems such as high-T{sub c} superconductors, heavy-fermion metals, and quasi-two-dimensional Fermi systems. It is shown that the basic properties and the universal behavior of strongly correlated Fermi systems can be described in the framework of the Fermi-condensate quantum phase transition and the well-known Landau paradigm of quasiparticles and the order parameter. The concept of fermion condensation may be fruitful in studying neutron stars, finite Fermi systems, ultra-cold gases in traps, and quark plasma. (reviews of topical problems)
Universal behavior of strongly correlated Fermi systems
International Nuclear Information System (INIS)
Shaginyan, Vasilii R; Amusia, M Ya; Popov, Konstantin G
2007-01-01
This review discusses the construction of a theory and the analysis of phenomena occurring in strongly correlated Fermi systems such as high-T c superconductors, heavy-fermion metals, and quasi-two-dimensional Fermi systems. It is shown that the basic properties and the universal behavior of strongly correlated Fermi systems can be described in the framework of the Fermi-condensate quantum phase transition and the well-known Landau paradigm of quasiparticles and the order parameter. The concept of fermion condensation may be fruitful in studying neutron stars, finite Fermi systems, ultra-cold gases in traps, and quark plasma. (reviews of topical problems)
Correlation control theory of chaotic laser systems
International Nuclear Information System (INIS)
Li Fuli.
1986-04-01
A novel control theory of chaotic systems is studied. The correlation functions are calculated and used as feedback signals of the chaotic lasers. Computer experiments have shown that in this way the chaotic systems can be controlled to have time-independent output when the external control parameters are in chaotic domain. (author)
Superconductivity in Correlated Fermions System | Babalola ...
African Journals Online (AJOL)
We have studied the Hubbard model which is a model that is used to describe the physics of strongly correlated Fermions systems. Using the Hubbard model, we worked on some systems in one dimension (1-D) at half fillings. We employed the numerical exact diagonalization technique and found out that there was a ...
Quantum Transport in Strongly Correlated Systems
DEFF Research Database (Denmark)
Bohr, Dan
2007-01-01
the density matrix renormalization group (DMRG) method. We present two DMRG setups for calculating the linear conductance of strongly correlated nanostructures in the infinitesimal source-drain voltage regime. The first setup describes the leads by modified real-space tight-binding chains, whereas the second....... Thus both coherence and correlation effects are important in this model, and the methods applied should be able to handle both these effects rigorously. We present the DMRG setup for this model and benchmark against existing Greens function results for the model. Then we present initial DMRG results...... screening plays a much less significant role than in bulk systems due to the reduced size of the objects, therefore making it necessary to consider the importance of correlations between electrons. The work presented in this thesis deals with quantum transport through strongly correlated systems using...
System Reliability Analysis Considering Correlation of Performances
Energy Technology Data Exchange (ETDEWEB)
Kim, Saekyeol; Lee, Tae Hee [Hanyang Univ., Seoul (Korea, Republic of); Lim, Woochul [Mando Corporation, Seongnam (Korea, Republic of)
2017-04-15
Reliability analysis of a mechanical system has been developed in order to consider the uncertainties in the product design that may occur from the tolerance of design variables, uncertainties of noise, environmental factors, and material properties. In most of the previous studies, the reliability was calculated independently for each performance of the system. However, the conventional methods cannot consider the correlation between the performances of the system that may lead to a difference between the reliability of the entire system and the reliability of the individual performance. In this paper, the joint probability density function (PDF) of the performances is modeled using a copula which takes into account the correlation between performances of the system. The system reliability is proposed as the integral of joint PDF of performances and is compared with the individual reliability of each performance by mathematical examples and two-bar truss example.
System Reliability Analysis Considering Correlation of Performances
International Nuclear Information System (INIS)
Kim, Saekyeol; Lee, Tae Hee; Lim, Woochul
2017-01-01
Reliability analysis of a mechanical system has been developed in order to consider the uncertainties in the product design that may occur from the tolerance of design variables, uncertainties of noise, environmental factors, and material properties. In most of the previous studies, the reliability was calculated independently for each performance of the system. However, the conventional methods cannot consider the correlation between the performances of the system that may lead to a difference between the reliability of the entire system and the reliability of the individual performance. In this paper, the joint probability density function (PDF) of the performances is modeled using a copula which takes into account the correlation between performances of the system. The system reliability is proposed as the integral of joint PDF of performances and is compared with the individual reliability of each performance by mathematical examples and two-bar truss example.
Two-particle correlations in reactor systems
International Nuclear Information System (INIS)
Mika, J.
1975-01-01
A study is made of the relationship between the general transport equation and the correlation matrix equation, in reactor systems. How some of the results obtained so far for the generalized transport equation can be simply translated to the correlation matrix equation is indicated. In particular, the semigroup formalism developed for the generalized transport equation is used to prove the existence and uniqueness of solution to the correlation matrix equation. The generalized transport equation is rigorously formulated in a Hilbert space of square integrable functions. The semigroup formalism for that equation is introduced and the solution expressed in terms of the semigroup. The correlation matrix equation is then formulated. It is shown how the semigroup formalism developed for the generalized transport equation can be applied to the correlation matrix equation and used to prove the existence theorem. Some applications of the semigroup formalism are then indicated. Firstly, the simple one point model obtained from the general equations is introduced. Secondly, the well known phenomenon of the linear increase with time of the components of the correlation matrix in a critical reactor is analyzed. Finally, it is shown how the singular perturbation method developed recently for the generalized transport equation can be applied to the correlation matrix equation. (U.K.)
Propagating wave correlations in complex systems
International Nuclear Information System (INIS)
Creagh, Stephen C; Gradoni, Gabriele; Hartmann, Timo; Tanner, Gregor
2017-01-01
We describe a novel approach for computing wave correlation functions inside finite spatial domains driven by complex and statistical sources. By exploiting semiclassical approximations, we provide explicit algorithms to calculate the local mean of these correlation functions in terms of the underlying classical dynamics. By defining appropriate ensemble averages, we show that fluctuations about the mean can be characterised in terms of classical correlations. We give in particular an explicit expression relating fluctuations of diagonal contributions to those of the full wave correlation function. The methods have a wide range of applications both in quantum mechanics and for classical wave problems such as in vibro-acoustics and electromagnetism. We apply the methods here to simple quantum systems, so-called quantum maps, which model the behaviour of generic problems on Poincaré sections. Although low-dimensional, these models exhibit a chaotic classical limit and share common characteristics with wave propagation in complex structures. (paper)
Correlations in small systems with ALICE
Lakomov, Igor
2016-01-01
ALICE is dedicated to the study of the strongly interacting matter, the so-called Quark-Gluon Plasma (QGP), formed in heavy-ion collisions at the LHC. In addition, ALICE also actively participated in the pp and p–Pb collision programs. In particular, the measurements of the twoparticle azimuthal correlations in pp collisions at √ s = 7 TeV and in p–Pb collisions at √ sNN = 5.02 TeV have been performed by the ALICE Collaboration during Run I of the LHC. Similar long-range correlations in p–Pb and Pb–Pb collisions have been observed on the near and away side — also known as the double ridge. Further investigations showed the importance of the Multi-Parton Interactions (MPI) in high-multiplicity collisions in small systems. In this work the ALICE results on the correlations in small systems are presented including MPI measurements in pp collisions.
A new digital correlation flaw detection system
International Nuclear Information System (INIS)
Lee, B.B.; Furgason, E.S.
1981-01-01
A new portable digital random signal flaw detection system is described which uses a digital delay line to replace the acoustic delay line of the original random signal system. Using this new system, a comparison was made between the two types of transmit signals which have been used in previous systems--m-sequences and random signals. This comparison has not been possible with these previous correlation flaw detection systems. Results indicated that for high-speed short code operation, the m-sequences produced slightly lower range sidelobes than typical samples of a clipped random signal. For normal long code operation, results indicated that system performance is essentially equivalent in resolution and signal-to-noise ratio using either m-sequences or clipped and sampled random signals. Further results also showed that for normal long code operation, the system produces outputs equivalent in resolution to pulse-echo systems, but with the added benefit of signal-to-noise ratio enhancement
Eddy Correlation Flux Measurement System (ECOR) Handbook
Energy Technology Data Exchange (ETDEWEB)
Cook, DR
2011-01-31
The eddy correlation (ECOR) flux measurement system provides in situ, half-hour measurements of the surface turbulent fluxes of momentum, sensible heat, latent heat, and carbon dioxide (CO2) (and methane at one Southern Great Plains extended facility (SGP EF) and the North Slope of Alaska Central Facility (NSA CF). The fluxes are obtained with the eddy covariance technique, which involves correlation of the vertical wind component with the horizontal wind component, the air temperature, the water vapor density, and the CO2 concentration.
Quantum Monte Carlo approaches for correlated systems
Becca, Federico
2017-01-01
Over the past several decades, computational approaches to studying strongly-interacting systems have become increasingly varied and sophisticated. This book provides a comprehensive introduction to state-of-the-art quantum Monte Carlo techniques relevant for applications in correlated systems. Providing a clear overview of variational wave functions, and featuring a detailed presentation of stochastic samplings including Markov chains and Langevin dynamics, which are developed into a discussion of Monte Carlo methods. The variational technique is described, from foundations to a detailed description of its algorithms. Further topics discussed include optimisation techniques, real-time dynamics and projection methods, including Green's function, reptation and auxiliary-field Monte Carlo, from basic definitions to advanced algorithms for efficient codes, and the book concludes with recent developments on the continuum space. Quantum Monte Carlo Approaches for Correlated Systems provides an extensive reference ...
Penjweini, Rozhin; Deville, Sarah; D'Olieslaeger, Lien; Berden, Mandy; Ameloot, Marcel; Ethirajan, Anitha
2015-11-28
The study of cell-nanoparticle interactions is an important aspect for understanding drug delivery using nanocarriers. In this regard, advances in fluorescence based microscopy are useful for the investigation of temporal and spatial behavior of nanoparticles (NPs) within the intracellular environment. In this work, we focus on the delivery of the naturally-occurring hydrophobic photosensitizer Hypericin in human lung carcinoma A549 cells by using biodegradable poly L-lactic acid NPs. For the first time, Hypericin containing NPs are prepared by combining the miniemulsion technique with the solvent evaporation method. This approach yields an efficient loading of the NPs with Hypericin and allows for additional cargo molecules. To monitor the release of Hypercin from the NPs, an additional fluorescent lipophilic dye Coumarin-6 is incorporated in the NPs. Temporal and spatiotemporal image correlation spectroscopy is used to determine the fate of the NPs carrying the potential cargo. Both directed and non-directed motions are detected. By using image cross-correlation spectroscopy and specific fluorescent labeling of endosomes, lysosomes and mitochondria, the dynamics of the cargo loaded NPs in association with the organelles is studied. Copyright © 2015 Elsevier B.V. All rights reserved.
Magnetic correlations in a classic Mott system
International Nuclear Information System (INIS)
Bao, W.; Broholm, C.; Aeppli, G.; Carter, S.A.; Dai, D.; Frost, C.D.
1997-07-01
The metal-insulator transition in V 2 O 3 causes a fundamental change in its magnetism. While the antiferromagnetic insulator (AFI) is a Heisenberg localized spin system, the antiferromagnetism in the strongly correlated metal is determined by a Fermi surface instability. Paramagnetic fluctuations in the metal and insulator represent similar spatial spin correlations, but are unrelated to the long range order in the AFI. The phase transition to the AFI induces an abrupt switching of magnetic correlations to a different magnetic wave vector. The AFI transition, therefore, is not a conventional spin order-disorder transition. Instead it is accounted for by an ordering in the occupation of the two degenerate d-orbitals at the Fermi level
Directory of Open Access Journals (Sweden)
Takashi Yanagisawa
2015-01-01
Full Text Available We investigate the ground state of two-dimensional Hubbard model on the basis of the variational Monte Carlo method. We use wave functions that include kinetic correlation and doublon-holon correlation beyond the Gutzwiller ansatz. It is still not clear whether the Hubbard model accounts for high-temperature superconductivity. The antiferromagnetic correlation plays a key role in the study of pairing mechanism because the superconductive phase exists usually close to the antiferromagnetic phase. We investigate the stability of the antiferromagnetic state when holes are doped as a function of the Coulomb repulsion U. We show that the antiferromagnetic correlation is suppressed as U is increased exceeding the bandwidth. High-temperature superconductivity is possible in this region with enhanced antiferromagnetic spin fluctuation and pairing interaction.
TRANSPORT PROPERTIES OF THE STRONGLY CORRELATED SYSTEMS
Directory of Open Access Journals (Sweden)
T.Domanski
2004-01-01
Full Text Available The transport properties of various systems are studied here in the context of three different models. These are: - the disordered Hubbard model applicable to correlated binary alloys with a general disorder, - the Anderson model used in describing the Kondo physics of a quantum dot connected to the external superconducting leads, and - the Ranninger-Robaszkiewicz model applied to the study of optical properties of the system with preformed electron pairs above the temperature of transition to the superconducting state. We calculate the density of states, specific heat, the Wilson ratio and conductivity of the correlated binary alloy with off-diagonal disorder. We investigate the conditions under which the Kondo peak appears in the density of states and in the conductance of a dot coupled to the external superconducting leads. We analyze the effect of the pseudogap on the optical spectra in the high temperature superconductors described by the boson-fermion model.
Strong correlations in few-fermion systems
Energy Technology Data Exchange (ETDEWEB)
Bergschneider, Andrea
2017-07-26
In this thesis, I report on the deterministic preparation and the observation of strongly correlated few-fermion systems in single and double-well potentials. In a first experiment, we studied a system of one impurity interacting with a number of majority atoms which we prepared in a single potential well in the one-dimensional limit. With increasing number of majority particles, we observed a decrease in the quasi-particle residue which is in agreement with expectations from the Anderson orthogonality catastrophe. In a second experiment, we prepared two fermions in a double-well potential which represents the fundamental building block of the Fermi-Hubbard model. By increasing the repulsion between the two fermions, we observed the crossover into the antiferromagnetic Mott-insulator regime. Furthermore, I describe a new imaging technique, which allows spin-resolved single-atom detection both in in-situ and in time-of-flight. We use this technique to investigate the emergence of momentum correlations of two repulsive fermions in the ground state of the double well. With the methods developed in this thesis, we have established a framework for quantum simulation of strongly correlated many-body systems in tunable potentials.
Phase diagram of strongly correlated Fermi systems
International Nuclear Information System (INIS)
Zverev, M.V.; Khodel', V.A.; Baldo, M.
2000-01-01
Phase transitions in uniform Fermi systems with repulsive forces between the particles caused by restructuring of quasiparticle filling n(p) are analyzed. It is found that in terms of variables, i.e. density ρ, nondimensional binding constant η, phase diagram of a strongly correlated Fermi system for rather a wide class of interactions reminds of a puff-pastry pie. Its upper part is filled with fermion condensate, the lower one - with normal Fermi-liquid. They are separated by a narrow interlayer - the Lifshits phase, characterized by the Fermi multibound surface [ru
Electron-phonon interactions in correlated systems
International Nuclear Information System (INIS)
Wysokinski, K.I.
1996-01-01
There exist attempts to describe the superconducting mechanism operating in HTS as based on antiferromagnetic fluctuations. It is not our intention to dwell on the superconducting mechanism, even though this is very a important issue. The main aim is to discuss the problem of interplay between electron-phonon and electron-electron interactions in correlated systems. We believe such analysis can be of importance for various materials and not only HTS'S. We shall however mainly refer to experiments on this last class of superconductors. Severe complications are to be expected by studying the problem. As is well known electron correlations are very important in narrow band systems, where the relevant electronic scale E F is quite small. In those circumstances, the phonon energy scale ω D is of comparable magnitude, with the ratio ω D /E F of order 1 signalling a possible break down of the Migdal - Eliashberg description of the electron-phonon interaction in metals. Here we shall assume the validity of the Migdal-Eliashberg approximation and concentrate on the mutual influence of electron and phonon subsystems. In the next section we shall discuss experimental motivation for and theoretical work related to the present problem. Section 3 contains a brief discussion of our theory. It is a self-consistent theory a la Migdal with strong correlations treated with an auxiliary boson technique. We conclude with results and their discussion. (orig.)
Visualizing complex (hydrological) systems with correlation matrices
Haas, J. C.
2016-12-01
When trying to understand or visualize the connections of different aspects of a complex system, this often requires deeper understanding to start with, or - in the case of geo data - complicated GIS software. To our knowledge, correlation matrices have rarely been used in hydrology (e.g. Stoll et al., 2011; van Loon and Laaha, 2015), yet they do provide an interesting option for data visualization and analysis. We present a simple, python based way - using a river catchment as an example - to visualize correlations and similarities in an easy and colorful way. We apply existing and easy to use python packages from various disciplines not necessarily linked to the Earth sciences and can thus quickly show how different aquifers work or react, and identify outliers, enabling this system to also be used for quality control of large datasets. Going beyond earlier work, we add a temporal and spatial element, enabling us to visualize how a system reacts to local phenomena such as for example a river, or changes over time, by visualizing the passing of time in an animated movie. References: van Loon, A.F., Laaha, G.: Hydrological drought severity explained by climate and catchment characteristics, Journal of Hydrology 526, 3-14, 2015, Drought processes, modeling, and mitigation Stoll, S., Hendricks Franssen, H. J., Barthel, R., Kinzelbach, W.: What can we learn from long-term groundwater data to improve climate change impact studies?, Hydrology and Earth System Sciences 15(12), 3861-3875, 2011
Scattering from correlations in colloidal systems
International Nuclear Information System (INIS)
Hayter, J.B.
1984-01-01
Colloidal suspensions typically exhibit spatial correlations over distances of order 10-10 4 A, corresponding either to the size of individual particles (e.g., polymer chains, surfactant micelles) or to the range of interaction between particles (e.g., charged polymer lattices at low ionic strength). Apart from having fundamental intrinsic interest, such systems are also extremely useful as model systems with which to study, for example, non-Newtonian hydrodynamics, since temporal correlations are generally much longer lived (10 -8 -10 -3 sec) than those found in simple atomic or small molecular systems (10 -13 -10 -10 sec). Colloids have long been the subject of macroscopic phenomenological research (on rheological properties, for example), but it is only recently that microscopic light, x-ray and neutron scattering techniques have been applied to their study, in large part because of theoretical difficulties in understanding the scattering from dense liquid-like systems of interacting particles. For spherical colloids, such theoretical problems have now been largely overcome, and for anisotropic colloids experimental techniques are being developed which circumvent the intractable theoretical areas. This paper will first review some static light and small-angle neutron scattering (SANS) results on colloidal suspensions, both at equilibrium and in steady-state non-equilibrium situations, and will then discuss some dynamic measurements on polymer solutions and melts made using the neutron spin-echo (NSE) technique. Emphasis is placed on experiments which have a possible counterpart in synchrotron radiation studies. In particular, NSE extends the results of photon correlation spectroscopy (PCS) to larger momentum transfers and shorter time-scales than are available with visible light, and the extension of PCS to short wavelength on a synchrotron source would be of similar fundamental interest
Eddy Correlation Flux Measurement System Handbook
Energy Technology Data Exchange (ETDEWEB)
Cook, D. R. [Argonne National Lab. (ANL), Argonne, IL (United States)
2016-01-01
The eddy correlation (ECOR) flux measurement system provides in situ, half-hour measurements of the surface turbulent fluxes of momentum, sensible heat, latent heat, and carbon dioxide (CO2) (and methane at one Southern Great Plains extended facility (SGP EF) and the North Slope of Alaska Central Facility (NSA CF). The fluxes are obtained with the eddy covariance technique, which involves correlation of the vertical wind component with the horizontal wind component, the air temperature, the water vapor density, and the CO2 concentration. The instruments used are: • a fast-response, three-dimensional (3D) wind sensor (sonic anemometer) to obtain the orthogonal wind components and the speed of sound (SOS) (used to derive the air temperature) • an open-path infrared gas analyzer (IRGA) to obtain the water vapor density and the CO2 concentration, and • an open-path infrared gas analyzer (IRGA) to obtain methane density and methane flux at one SGP EF and at the NSA CF. The ECOR systems are deployed at the locations where other methods for surface flux measurements (e.g., energy balance Bowen ratio [EBBR] systems) are difficult to employ, primarily at the north edge of a field of crops. A Surface Energy Balance System (SEBS) has been installed collocated with each deployed ECOR system in SGP, NSA, Tropical Western Pacific (TWP), ARM Mobile Facility 1 (AMF1), and ARM Mobile Facility 2 (AMF2). The surface energy balance system consists of upwelling and downwelling solar and infrared radiometers within one net radiometer, a wetness sensor, and soil measurements. The SEBS measurements allow the comparison of ECOR sensible and latent heat fluxes with the energy balance determined from the SEBS and provide information on wetting of the sensors for data quality purposes. The SEBS at one SGP and one NSA site also support upwelling and downwelling PAR measurements to qualify those two locations as Ameriflux sites.
Correlation effects in superconducting quantum dot systems
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.
Correlated Levy Noise in Linear Dynamical Systems
International Nuclear Information System (INIS)
Srokowski, T.
2011-01-01
Linear dynamical systems, driven by a non-white noise which has the Levy distribution, are analysed. Noise is modelled by a specific stochastic process which is defined by the Langevin equation with a linear force and the Levy distributed symmetric white noise. Correlation properties of the process are discussed. The Fokker-Planck equation driven by that noise is solved. Distributions have the Levy shape and their width, for a given time, is smaller than for processes in the white noise limit. Applicability of the adiabatic approximation in the case of the linear force is discussed. (author)
Atomic physics of strongly correlated systems
International Nuclear Information System (INIS)
Lin, C.D.
1986-01-01
This abstract summarizes the progress made in the last year and the future plans of our research in the study of strongly correlated atomic systems. In atomic structure and atomic spectroscopy we are investigating the classification and supermultiplet structure of doubly excited states. We are also beginning the systematic study of triply excited states. In ion-atom collisions, we are exploring an AO-MO matching method for treating multi-electron collision systems to extract detailed information such as subshell cross sections, alignment and orientation parameters, etc. We are also beginning ab initio calculations on the angular distributions for electron transfer processes in low-energy (about 10-100eV/amu) ion-atom collisions in a full quantum mechanical treatment of the motion of heavy particles
Quantum frustrated and correlated electron systems
Directory of Open Access Journals (Sweden)
P Thalmeier
2008-06-01
Full Text Available Quantum phases and fluctuations in correlated electron systems with frustration and competing interactions are reviewed. In the localized moment case the S=1/2 J1 - J2 - model on a square lattice exhibits a rich phase diagram with magnetic as well as exotic hidden order phases due to the interplay of frustration and quantum fluctuations. Their signature in magnetocaloric quantities and the high field magnetization are surveyed. The possible quantum phase transitions are discussed and applied to layered vanadium oxides. In itinerant electron systems frustration is an emergent property caused by electron correlations. It leads to enhanced spin fluctuations in a very large region of momentum space and therefore may cause heavy fermion type low temperature anomalies as in the 3d spinel compound LiV2O4 . Competing on-site and inter-site electronic interactions in Kondo compounds are responsible for the quantum phase transition between nonmagnetic Kondo singlet phase and magnetic phase such as observed in many 4f compounds. They may be described by Kondo lattice and simplified Kondo necklace type models. Their quantum phase transitions are investigated by numerical exact diagonalization and analytical bond operator methods respectively.
Electron correlations in narrow band systems
International Nuclear Information System (INIS)
Kishore, R.
1983-01-01
The effect of the electron correlations in narrow bands, such as d(f) bands in the transition (rare earth) metals and their compounds and the impurity bands in doped semiconductors is studied. The narrow band systems is described, by the Hubbard Hamiltonian. By proposing a local self-energy for the interacting electron, it is found that the results are exact in both atomic and band limits and reduce to the Hartree Fock results for U/Δ → 0, where U is the intra-atomic Coulomb interaction and Δ is the bandwidth of the noninteracting electrons. For the Lorentzian form of the density of states of the noninteracting electrons, this approximation turns out to be equivalent to the third Hubbard approximation. A simple argument, based on the mean free path obtained from the imaginary part of the self energy, shows how the electron correlations can give rise to a discontinous metal-nonmetal transition as proposed by Mott. The band narrowing and the existence of the satellite below the Fermi energy in Ni, found in photoemission experiments, can also be understood. (Author) [pt
Strongly Correlated Electron Systems: An Operatorial Perspective
Di Ciolo, Andrea; Avella, Adolfo
2018-05-01
We discuss the operatorial approach to the study of strongly correlated electron systems and show how the exact solution of target models on small clusters chosen ad-hoc (minimal models) can suggest very efficient bulk approximations. We use the Hubbard model as case study (target model) and we analyze and discuss the crucial role of spin fluctuations in its 2-site realization (minimal model). Accordingly, we devise a novel three-pole approximation for the 2D case, including in the basic field an operator describing the dressing of the electronic one by the nearest-neighbor spin-fluctuations. Such a solution is in very good agreement with the exact one in the minimal model (2-site case) and performs very well once compared to advanced (semi-)numerical methods in the 2D case, being by far less computational-resource demanding.
Geometrical optics in correlated imaging systems
International Nuclear Information System (INIS)
Cao Dezhong; Xiong Jun; Wang Kaige
2005-01-01
We discuss the geometrical optics of correlated imaging for two kinds of spatial correlations corresponding, respectively, to a classical thermal light source and a quantum two-photon entangled source. Due to the different features in the second-order spatial correlation, the two sources obey different imaging equations. The quantum entangled source behaves as a mirror, whereas the classical thermal source looks like a phase-conjugate mirror in the correlated imaging
Superconductivity in strongly correlated electron systems: successes and open questions
International Nuclear Information System (INIS)
Shastry, B. Sriram
2000-01-01
Correlated electronic systems and superconductivity is a field which has unique track record of producing exciting new phases of matter. The article gives an overview of trends in solving the problems of superconductivity and correlated electronic systems
DEFF Research Database (Denmark)
Enkavi, Giray; Mikkolainen, Heikki; Güngör, Burçin
2017-01-01
remained elusive. Here, based on an extensive set of atomistic simulations and free energy calculations, we clarify the mechanism and energetics of npc2-membrane binding and characterize the roles of physiologically relevant key lipids associated with the binding process. Our results capture in atomistic......Niemann-Pick Protein C2 (npc2) is a small soluble protein critical for cholesterol transport within and from the lysosome and the late endosome. Intriguingly, npc2-mediated cholesterol transport has been shown to be modulated by lipids, yet the molecular mechanism of npc2-membrane interactions has......). This mode is associated with cholesterol uptake and release. On the other hand, the second mode (Supine) places the cholesterol binding pocket away from the membrane surface, but has overall higher membrane binding affinity. We determined that bis(monoacylglycero)phosphate (bmp) is specifically required...
On defense strategies for system of systems using aggregated correlations
Energy Technology Data Exchange (ETDEWEB)
Rao, Nageswara S. [ORNL; Imam, Neena [ORNL; Ma, Chris Y. T. [Hang Seng Management College, Hon Kong; Hausken, Kjell [University of Stavanger, Norway; He, Fei [Texas A& M University, Kingsville, TX, USA; Zhuang, Jun [University at Buffalo (SUNY)
2017-04-01
We consider a System of Systems (SoS) wherein each system Si, i = 1; 2; ... ;N, is composed of discrete cyber and physical components which can be attacked and reinforced. We characterize the disruptions using aggregate failure correlation functions given by the conditional failure probability of SoS given the failure of an individual system. We formulate the problem of ensuring the survival of SoS as a game between an attacker and a provider, each with a utility function composed of asurvival probability term and a cost term, both expressed in terms of the number of components attacked and reinforced. The survival probabilities of systems satisfy simple product-form, first-order differential conditions, which simplify the Nash Equilibrium (NE) conditions. We derive the sensitivity functions that highlight the dependence of SoS survival probability at NE on cost terms, correlation functions, and individual system survival probabilities.We apply these results to a simplified model of distributed cloud computing infrastructure.
Asymptotic Likelihood Distribution for Correlated & Constrained Systems
Agarwal, Ujjwal
2016-01-01
It describes my work as summer student at CERN. The report discusses the asymptotic distribution of the likelihood ratio for total no. of parameters being h and 2 out of these being are constrained and correlated.
Pair correlation of particles in strongly nonideal systems
International Nuclear Information System (INIS)
Vaulina, O. S.
2012-01-01
A new semiempirical model is proposed for describing the spatial correlation between interacting particles in nonideal systems. The developed model describes the main features in the behavior of the pair correlation function for crystalline structures and can also be used for qualitative and quantitative description of the spatial correlation of particles in strongly nonideal liquid systems. The proposed model is compared with the results of simulation of the pair correlation function.
Two particle correlations in small systems
Palmeiro Pazos, Brais
2015-01-01
The present report summarizes the work on the Summer Student project within the ALICE Collaboration. The aim of the project is to study the two-particle correlations in peripheral Pb-Pb collisions with the ALICE detector. The first part of this project is the development of a Toy Monte Carlo (MC) generator to reproduce and understand the Physics behind and probe the analysis in a controlled data set. Then, once the Toy MC is fully understood, it is possible to move to real data where some unexpected effects might appear and should be comprehended in order to have the whole physical picture of the peripheral Pb-Pb collisions.
Correlation function behavior in quantum systems which are classically chaotic
International Nuclear Information System (INIS)
Berman, G.P.; Kolovsky, A.R.
1983-01-01
The time behavior of a phase correlation function for dynamical quantum systems which are classically chaotic is considered. It is shown that under certain conditions there are three time regions of the quantum correlations behavior; the region of classical stochasticity (exponential decay of quantum correlations); the region of the correlations decay with a power law; the region of the constant level of the quantum correlations. The boundaries of these time regions are presented. The estimation of a remaining level of the quantum correlations is given. (orig.)
Electron correlation energy in confined two-electron systems
Energy Technology Data Exchange (ETDEWEB)
Wilson, C.L. [Chemistry Program, Centre College, 600 West Walnut Street, Danville, KY 40422 (United States); Montgomery, H.E., E-mail: ed.montgomery@centre.ed [Chemistry Program, Centre College, 600 West Walnut Street, Danville, KY 40422 (United States); Sen, K.D. [School of Chemistry, University of Hyderabad, Hyderabad 500 046 (India); Thompson, D.C. [Chemistry Systems and High Performance Computing, Boehringer Ingelheim Pharamaceuticals Inc., 900 Ridgebury Road, Ridgefield, CT 06877 (United States)
2010-09-27
Radial, angular and total correlation energies are calculated for four two-electron systems with atomic numbers Z=0-3 confined within an impenetrable sphere of radius R. We report accurate results for the non-relativistic, restricted Hartree-Fock and radial limit energies over a range of confinement radii from 0.05-10a{sub 0}. At small R, the correlation energies approach limiting values that are independent of Z while at intermediate R, systems with Z{>=}1 exhibit a characteristic maximum in the correlation energy resulting from an increase in the angular correlation energy which is offset by a decrease in the radial correlation energy.
Quantum coherence and correlations in quantum system
Xi, Zhengjun; Li, Yongming; Fan, Heng
2015-01-01
Criteria of measure quantifying quantum coherence, a unique property of quantum system, are proposed recently. In this paper, we first give an uncertainty-like expression relating the coherence and the entropy of quantum system. This finding allows us to discuss the relations between the entanglement and the coherence. Further, we discuss in detail the relations among the coherence, the discord and the deficit in the bipartite quantum system. We show that, the one-way quantum deficit is equal to the sum between quantum discord and the relative entropy of coherence of measured subsystem. PMID:26094795
Stochastic systems with cross-correlated Gaussian white noises
International Nuclear Information System (INIS)
Wang Cheng-Yu; Song Yu-Min; Zhou Peng; Yang Hai; Gao Yun
2010-01-01
This paper theoretically investigates three stochastic systems with cross-correlation Gaussian white noises. Both steady state properties of the stochastic nonlinear systems and the nonequilibrium transitions induced by the cross-correlated noises are studied. The stationary solutions of the Fokker—Planck equation for three specific examples are analysed. It is shown explicitly that the cross-correlation of white noises can induce nonequilibrium transitions
The n-level spectral correlations for chaotic systems
International Nuclear Information System (INIS)
Nagao, Taro; Mueller, Sebastian
2009-01-01
We study the n-level spectral correlation functions of classically chaotic quantum systems without time-reversal symmetry. According to Bohigas, Giannoni and Schmit's universality conjecture, it is expected that the correlation functions are in agreement with the prediction of the circular unitary ensemble (CUE) of random matrices. A semiclassical resummation formalism allows us to express the correlation functions as sums over pseudo-orbits. Using an extended version of the diagonal approximation on the pseudo-orbit sums, we derive the n-level correlation functions identical to the n x n determinantal correlation functions of the CUE.
Dual fermion approach to disordered correlated systems
International Nuclear Information System (INIS)
Haase, Patrick
2015-01-01
Disorder is ubiquitous in real materials and influences the physical properties like the conductivity to varying degrees. If electron-electron interactions are strong, theoretical and numerical treatment of these systems becomes challenging. In this thesis a numerical approach is developed to address these systems, treating both interactions and disorder on equal footing. The approach is based on the dual fermion approach for interacting systems developed by Rubtsov et al. Terletska et al. applied the ideas of the dual fermion approach to disordered non-interacting systems. In this approach, the replica trick is used to integrate out the disorder in favor of an effective electron-electron interaction. We extended the approach from Terletska et al. to treat disordered interacting systems. Dual Fermions allow to take into account non-local fluctuations by means of a perturbative expansion around an impurity problem. The impurity reference system is determined self-consistently, analogously to the dynamical mean-field theory. The perturbative expansion is expected to yield good results for small and large values of interaction strength and disorder. A priori, it is not clear what to expect for intermediate values, but experience shows that oftentimes good results are obtained for this region. An advantage of the dual fermion approach is that there is no sign-problem for a single orbital model if quantum Monte Carlo is used to solve the interacting reference system. Additionally, perturbation theory is usually numerically much cheaper than fully solving an interacting lattice or cluster problem. Thus, the dual fermion approach allows to address regions of parameter space that are not accessible to lattice quantum Monte Carlo calculations or cluster extension of dynamical mean-field theory. Cluster extensions of the dynamical mean-field theory are for example the dynamical cluster approximation or the cellular dynamical mean-field theory. The new approach is benchmarked
Closed hierarchy of correlations in Markovian open quantum systems
International Nuclear Information System (INIS)
Žunkovič, Bojan
2014-01-01
We study the Lindblad master equation in the space of operators and provide simple criteria for closeness of the hierarchy of equations for correlations. We separately consider the time evolution of closed and open systems and show that open systems satisfying the closeness conditions are not necessarily of Gaussian type. In addition, we show that dissipation can induce the closeness of the hierarchy of correlations in interacting quantum systems. As an example we study an interacting optomechanical model, the Fermi–Hubbard model, and the Rabi model, all coupled to a fine-tuned Markovian environment and obtain exact analytic expressions for the time evolution of two-point correlations. (paper)
Quantum correlation of high dimensional system in a dephasing environment
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.
Correlation Functions in Open Quantum-Classical Systems
Hsieh, Chang-Yu; Kapral, Raymond
2013-01-01
Quantum time correlation functions are often the principal objects of interest in experimental investigations of the dynamics of quantum systems. For instance, transport properties, such as diffusion and reaction rate coefficients, can be obtained by integrating these functions. The evaluation of such correlation functions entails sampling from quantum equilibrium density operators and quantum time evolution of operators. For condensed phase and complex systems, where quantum dynamics is diff...
Markovian Limit of a Spatio-Temporal Correlated Open Systems
Monnai, T.
Large fluctuation of Brownian particles is affected by the finiteness of the correlation length of the background noise field. Indeed a Fokker—Planck equation is derived in a Markovian limit of a spatio-temporal short correlated noise. Corresponding kinetic quantities are renormalized due to the spatio-temporal memory. We also investigate the case of open system by connecting a thermostat to the system.
A Systems-Theoretical Generalization of Non-Local Correlations
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.
A multimodal stress monitoring system with canonical correlation analysis.
Unsoo Ha; Changhyeon Kim; Yongsu Lee; Hyunki Kim; Taehwan Roh; Hoi-Jun Yoo
2015-08-01
The multimodal stress monitoring headband is proposed for mobile stress management system. It is composed of headband and earplugs. Electroencephalography (EEG), hemoencephalography (HEG) and heart-rate variability (HRV) can be achieved simultaneously in the proposed system for user status estimation. With canonical correlation analysis (CCA) and temporal-kernel CCA (tkCCA) algorithm, those different signals can be combined for maximum correlation. Thanks to the proposed combination algorithm, the accuracy of the proposed system increased up to 19 percentage points than unimodal monitoring system in n-back task.
Correlation Between Information Technology And Management Information Systems Quality
Directory of Open Access Journals (Sweden)
Annisa Fitri Anggraeni
2015-08-01
Full Text Available The aim of this research is to find out the correlation between Information Technology and Management Information System Quality. This research applies literature review from various theories and previously conducted research where controversies between Information Technology and Management Information Systems. The result of this research shows that Information Technology is a part of Management Information System and supports the performance of Management Information Systems.
Quantum correlations for bipartite continuous-variable systems
Ma, Ruifen; Hou, Jinchuan; Qi, Xiaofei; Wang, Yangyang
2018-04-01
Two quantum correlations Q and Q_P for (m+n)-mode continuous-variable systems are introduced in terms of average distance between the reduced states under the local Gaussian positive operator-valued measurements, and analytical formulas of these quantum correlations for bipartite Gaussian states are provided. It is shown that the product states do not contain these quantum correlations, and conversely, all (m+n)-mode Gaussian states with zero quantum correlations are product states. Generally, Q≥ Q_{P}, but for the symmetric two-mode squeezed thermal states, these quantum correlations are the same and a computable formula is given. In addition, Q is compared with Gaussian geometric discord for symmetric squeezed thermal states.
Multi-particle correlations in quaternionic quantum systems
International Nuclear Information System (INIS)
Brumby, S.P.; Joshi, G.C.
1994-01-01
The authors investigated the outcomes of measurements on correlated, few-body quantum systems described by a quaternionic quantum mechanics that allows for regions of quaternionic curvature. It was found that a multi particles interferometry experiment using a correlated system of four nonrelativistic, spin-half particles has the potential to detect the presence of quaternionic curvature. Two-body systems, however, are shown to give predictions identical to those of standard quantum mechanics when relative angles are used in the construction of the operators corresponding to measurements of particle spin components. 15 refs
Correlation functions for Hermitian many-body systems: Necessary conditions
International Nuclear Information System (INIS)
Brown, E.B.
1994-01-01
Lee [Phys. Rev. B 47, 8293 (1993)] has shown that the odd-numbered derivatives of the Kubo autocorrelation function vanish at t=0. We show that this condition is based on a more general property of nondiagonal Kubo correlation functions. This general property provides that certain functional forms (e.g., simple exponential decay) are not admissible for any symmetric or antisymmetric Kubo correlation function in a Hermitian many-body system. Lee's result emerges as a special case of this result. Applications to translationally invariant systems and systems with rotational symmetries are also demonstrated
Resonant x-ray scattering in correlated systems
Ishihara, Sumio
2017-01-01
The research and its outcomes presented here is devoted to the use of x-ray scattering to study correlated electron systems and magnetism. Different x-ray based methods are provided to analyze three dimensional electron systems and the structure of transition-metal oxides. Finally the observation of multipole orderings with x-ray diffraction is shown.
Resonant X-ray scattering in correlated systems
Energy Technology Data Exchange (ETDEWEB)
Murakami, Youichi [High Energy Accelerator Research Organization, Tsukuba, Ibaraki (Japan). Inst. of Materials Structure Science; Ishihara, Sumio (ed.) [Tohoku Univ., Sendai, Miyagi (Japan). Dept. of Physics
2017-03-01
The research and its outcomes presented here is devoted to the use of X-ray scattering to study correlated electron systems and magnetism. Different X-ray based methods are provided to analyze three dimensional electron systems and the structure of transition-metal oxides. Finally the observation of multipole orderings with X-ray diffraction is shown.
A Generalized Correlation Plot Package for the CEBAF Control System
International Nuclear Information System (INIS)
D. Wu; W. Akers; S. Schaffner; H. Shoaee; W. A. Watson; D. Wetherholt
1996-01-01
The Correlation Package is a general facility for data acquisition and analysis serving as an online environment for performing a wide variety of machine physics experiments and engineering diagnostics. Typical correlation experiments consist of an initial set of actions followed by stepping one or two accelerator parameters while measuring up to several hundred control system parameters. The package utilizes the CDEV [1] device API to access accelerator systems. A variety of analysis and graphics tools are included through integration with the Matlab math modeling package. A post- acquisition script capability is available to automate the data reduction process. A callable interface allows this facility to serve as the data acquisition and analysis engine for high level applications. A planned interface to archived accelerator data will allow the same analysis and graphics tools to be used for viewing and correlating history data. The object oriented design and C++ implementation details as well as the current status of the Correlation Package will be presented
Correlation matrices of two-mode bosonic systems
International Nuclear Information System (INIS)
Pirandola, Stefano; Serafini, Alessio; Lloyd, Seth
2009-01-01
We present a detailed analysis of all the algebraic conditions an arbitrary 4x4 symmetric matrix must satisfy in order to represent the correlation matrix of a two-mode bosonic system. Then, we completely clarify when this arbitrary matrix can represent the correlation matrix of a separable or entangled Gaussian state. In this analysis, we introduce alternative sets of conditions, which are expressed in terms of local symplectic invariants.
CORRELATION BETWEEN HUMAN NEEDS SYSTEM - PERSONALITY - HUMAN MOTIVATION
Directory of Open Access Journals (Sweden)
Mirela MINICA
2015-07-01
Full Text Available The article highlights the main attributes of an economic approach of needs and preferences, with detailed focus on the correlation between meta-needs and personality, by correlating the principle of hierarchy established by Maslow with the balance theory. Adopting an integrated system of human capital motivation, which takes into account the complex aspects involved in the knowledge society, represents a managerial requirement for any organisation.
A distributed timing system for synchronizing control and data correlation
International Nuclear Information System (INIS)
Stettler, M.; Thuot, M.; Dalesio, L.R.; Cole, R.; Fite, C.; Slentz, G.; Warren, D.
1992-01-01
Synchronization is necessary in experimental physics machines to provide positive control over related events. The Ground Test Accelerator (GTA) timing system provides this function through a distributed control system, known as the Experimental Physics and Industrial Control System (EPICS). The EPICS timing system was designed to take advantage of a distributed architecture, and provides time stamping for synchronous data correlation as well as event control. The system has been successfully demonstrated on over a dozen controller nodes for operation and data analysis. The design of the hardware, software, and operational results are discussed. (author). 2 refs., 4 figs
A distributed timing system for sychronizing control and data correlation
International Nuclear Information System (INIS)
Stettler, M.; Thout, M.; Dalesio, L.R.; Cole, R.; Fite, C.; Slentz, G.; Warren, D.
1992-01-01
Synchronization is necessary in experimental physics machines to provide positive control over related events. The Ground Test Accelerator (GTA) timing system provides this function through a distributed control system, known as the Experimental Physics and Industrial Control System (EPICS). The EPICS timing system was designed to take advantage of a distributed architecture, and provides time stamping for synchronous data correlation as well as event control. The system has been successfully demonstrated on over a dozen controller nodes for operation and data analysis. The design of the hardware, software, and operational results are discussed
On-Chip Correlator for Passive Wireless SAW Multisensor Systems
Directory of Open Access Journals (Sweden)
Liqiang Xie
2016-01-01
Full Text Available For decoding the asynchronous superposition of response signals from different sensors, it is a challenge to achieve correlation in a code division multiplexing (CDM based passive wireless surface acoustic wave (SAW multisensor system. Therefore, an on-chip correlator scheme is developed in this paper. In contrast to conventional CDM-based systems, this novel scheme enables the correlations to be operated at the SAW sensors, instead of the reader. Thus, the response signals arriving at the reader are the result of cross-correlation on the chips. It is then easy for the reader to distinguish the sensor that is matched with the interrogating signal. The operation principle, signal analysis, and simulation of the novel scheme are described in the paper. The simulation results show the response signals from the correlations of the sensors. A clear spike pulse is presented in the response signals, when a sensor code is matched with the interrogating code. Simulations verify the feasibility of the on-chip correlator concept.
A semiclassical treatment of correlation energy for nuclear systems
International Nuclear Information System (INIS)
Nielsen, M.
1988-01-01
Starting with the separation of the many-body density operator in two parts, one describing the one-body aspects of the full density and the other containing all dynamic correlations information, the semiclassical approximation for the system correlation energy, was calculated. It is showm that, in this case, the Gaussian Wave Packets Phase Space Representation is more convenient than the Wely-Wigner Rrepresentation for the analysis of the semiclassical correlation energy. Using a phenomenological interaction, the correlation energy to the nuclear matter and some simmetric finite nucleus was calculated. The Fermi Surface Diffusivity, was also calculated. Finally, from the relation between this theory and the pertubation theory, we have done some considerations about the viability on the local densities expansion for energy functionals. (author) [pt
Statistical fluctuations and correlations in hadronic equilibrium systems
Energy Technology Data Exchange (ETDEWEB)
Hauer, Michael
2010-06-17
This thesis is dedicated to the study of fluctuation and correlation observables of hadronic equilibrium systems. The statistical hadronization model of high energy physics, in its ideal, i.e. non-interacting, gas approximation is investigated in different ensemble formulations. The hypothesis of thermal and chemical equilibrium in high energy interaction is tested against qualitative and quantitative predictions. (orig.)
Statistical fluctuations and correlations in hadronic equilibrium systems
International Nuclear Information System (INIS)
Hauer, Michael
2010-01-01
This thesis is dedicated to the study of fluctuation and correlation observables of hadronic equilibrium systems. The statistical hadronization model of high energy physics, in its ideal, i.e. non-interacting, gas approximation is investigated in different ensemble formulations. The hypothesis of thermal and chemical equilibrium in high energy interaction is tested against qualitative and quantitative predictions. (orig.)
QUANTUM AND CLASSICAL CORRELATIONS IN GAUSSIAN OPEN QUANTUM SYSTEMS
Directory of Open Access Journals (Sweden)
Aurelian ISAR
2015-01-01
Full Text Available In the framework of the theory of open systems based on completely positive quantum dynamical semigroups, we give a description of the continuous-variable quantum correlations (quantum entanglement and quantum discord for a system consisting of two noninteracting bosonic modes embedded in a thermal environment. We solve the Kossakowski-Lindblad master equation for the time evolution of the considered system and describe the entanglement and discord in terms of the covariance matrix for Gaussian input states. For all values of the temperature of the thermal reservoir, an initial separable Gaussian state remains separable for all times. We study the time evolution of logarithmic negativity, which characterizes the degree of entanglement, and show that in the case of an entangled initial squeezed thermal state, entanglement suppression takes place for all temperatures of the environment, including zero temperature. We analyze the time evolution of the Gaussian quantum discord, which is a measure of all quantum correlations in the bipartite state, including entanglement, and show that it decays asymptotically in time under the effect of the thermal bath. This is in contrast with the sudden death of entanglement. Before the suppression of the entanglement, the qualitative evolution of quantum discord is very similar to that of the entanglement. We describe also the time evolution of the degree of classical correlations and of quantum mutual information, which measures the total correlations of the quantum system.
International Conference on Strongly Correlated Electron Systems 2017 (SCES2017)
2018-05-01
The 2017 International Conference on Strongly Correlated Electron Systems, SCES 2017, took place at the Clarion Congress Hotel in Prague, Czech Republic from July 17 to 21, 2017. The meeting was held under the auspices of the Department of Condensed Matter Physics of the Faculty of Mathematics and Physics of the Charles University.
Levitation and percolation in quantum Hall systems with correlated disorder
Song, Hui; Maruyama, Isao; Hatsugai, Yasuhiro
2007-01-01
We investigate the integer quantum Hall system in a two dimensional lattice model with spatially correlated disorder by using the efficient method to calculate the Chern number proposed by Fukui et al. [J. Phys. Soc. Jpn. 74, 1674 (2005)]. Distribution of charge density indicates that the extended states at the center of each Landau band have percolating current paths, which are topologically equivalent to the edge states that exist in a system with boundaries. As increasing the strength of d...
Spatial Correlation Characterization of a Full Dimension Massive MIMO System
Nadeem, Qurrat-Ul-Ain
2017-02-07
Elevation beamforming and Full Dimension MIMO (FD-MIMO) are currently active areas of research and standardization in 3GPP LTE-Advanced. FD-MIMO utilizes an active antenna array system (AAS), that provides the ability of adaptive electronic beam control over the elevation dimension, resulting in a better system performance as compared to the conventional 2D MIMO systems. FD-MIMO is more advantageous when amalgamated with massive MIMO systems, in that it exploits the additional degrees of freedom offered by a large number of antennas in the elevation. To facilitate the evaluation of these systems, a large effort in 3D channel modeling is needed. This paper aims at providing a summary of the recent 3GPP activity around 3D channel modeling. The 3GPP proposed approach to model antenna radiation pattern is compared with the ITU approach. A closed-form expression is then worked out for the spatial correlation function (SCF) for channels constituted by individual antenna elements in the array by exploiting results on spherical harmonics and Legendre polynomials. The proposed expression can be used to obtain correlation coefficients for any arbitrary 3D propagation environment. Simulation results corroborate and study the derived spatial correlation expression. The results are directly applicable to the analysis of future 5G 3D massive MIMO systems.
Anti-correlation and subsector structure in financial systems
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.
Correlation Functions in Open Quantum-Classical Systems
Directory of Open Access Journals (Sweden)
Chang-Yu Hsieh
2013-12-01
Full Text Available Quantum time correlation functions are often the principal objects of interest in experimental investigations of the dynamics of quantum systems. For instance, transport properties, such as diffusion and reaction rate coefficients, can be obtained by integrating these functions. The evaluation of such correlation functions entails sampling from quantum equilibrium density operators and quantum time evolution of operators. For condensed phase and complex systems, where quantum dynamics is difficult to carry out, approximations must often be made to compute these functions. We present a general scheme for the computation of correlation functions, which preserves the full quantum equilibrium structure of the system and approximates the time evolution with quantum-classical Liouville dynamics. Several aspects of the scheme are discussed, including a practical and general approach to sample the quantum equilibrium density, the properties of the quantum-classical Liouville equation in the context of correlation function computations, simulation schemes for the approximate dynamics and their interpretation and connections to other approximate quantum dynamical methods.
Boson spectra and correlations for thermal locally equilibrium systems
International Nuclear Information System (INIS)
Sinyukov, Y.M.
1999-01-01
The single- and multi-particle inclusive spectra for strongly inhomogeneous thermal boson systems are studied using the method of statistical operator. The thermal Wick's theorem is generalized and the analytical solution of the problem for a boost-invariant expanding boson gas is found. The results demonstrate the effects of inhomogeneity for such a system: the spectra and correlations for particles with wavelengths larger than the system's homogeneity lengths change essentially as compared with the results based on the local Bose-Einstein thermal distributions. The effects noticeably grow for overpopulated media, where the chemical potential associated with violation of chemical equilibrium is large enough. (author)
Pair correlations in an expanding universe for a multicomponent system
International Nuclear Information System (INIS)
Kandrup, H.E.
1983-01-01
Fall and Saslaw have derived an equation for the growth of pair correlations in an expanding universe of identical self-gravitating point masses which is correlation-free at some initial time. Their equation is rigorously true for the earliest stages of growth, assuming only that the system is spatially homogeneous and isotropic, and that it is characterized in the ''comoving frame'' by a Maxwellian distribution of velocities. This paper generalizes their analysis to the case of a multicomponent system of particles with different masses, each species of which is characterized by a Maxwellian distribution at the same temperature. Here there are two types of pair correlations to consider, namely among members of the same species and among members of different species. The general behavior may be understood most readily by considering the covariance functions, which assume very simple forms. Thus one finds that the ''strength'' of the covariance scales, for sufficiently small radial separations, as the product of the masses, whereas the ''range'' of the covariance varies inversely as the square root of the reduced mass of the two constituents. This implies that, for two very different masses, the ''range'' will be set by the lighter constituent. Knowledge of the covariances also permits the calculation of such objects as the correlational energy densities of the various interactions. Consider, for example, a two-component system. Here one finds that even a very small contamination of heavy masses, which would have a negligible effect upon the total mass or kinetic energy densities, can increase the total correlational energy density, and hence decrease the time scale for the evolution of interesting structure, by orders of magnitude
Petascale Many Body Methods for Complex Correlated Systems
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.
Enhancement of Iris Recognition System Based on Phase Only Correlation
Directory of Open Access Journals (Sweden)
Nuriza Pramita
2011-08-01
Full Text Available Iris recognition system is one of biometric based recognition/identification systems. Numerous techniques have been implemented to achieve a good recognition rate, including the ones based on Phase Only Correlation (POC. Significant and higher correlation peaks suggest that the system recognizes iris images of the same subject (person, while lower and unsignificant peaks correspond to recognition of those of difference subjects. Current POC methods have not investigated minimum iris point that can be used to achieve higher correlation peaks. This paper proposed a method that used only one-fourth of full normalized iris size to achieve higher (or at least the same recognition rate. Simulation on CASIA version 1.0 iris image database showed that averaged recognition rate of the proposed method achieved 67%, higher than that of using one-half (56% and full (53% iris point. Furthermore, all (100% POC peak values of the proposed method was higher than that of the method with full iris points.
Fast electronic structure methods for strongly correlated molecular systems
International Nuclear Information System (INIS)
Head-Gordon, Martin; Beran, Gregory J O; Sodt, Alex; Jung, Yousung
2005-01-01
A short review is given of newly developed fast electronic structure methods that are designed to treat molecular systems with strong electron correlations, such as diradicaloid molecules, for which standard electronic structure methods such as density functional theory are inadequate. These new local correlation methods are based on coupled cluster theory within a perfect pairing active space, containing either a linear or quadratic number of pair correlation amplitudes, to yield the perfect pairing (PP) and imperfect pairing (IP) models. This reduces the scaling of the coupled cluster iterations to no worse than cubic, relative to the sixth power dependence of the usual (untruncated) coupled cluster doubles model. A second order perturbation correction, PP(2), to treat the neglected (weaker) correlations is formulated for the PP model. To ensure minimal prefactors, in addition to favorable size-scaling, highly efficient implementations of PP, IP and PP(2) have been completed, using auxiliary basis expansions. This yields speedups of almost an order of magnitude over the best alternatives using 4-center 2-electron integrals. A short discussion of the scope of accessible chemical applications is given
Disentangling multi-level systems: averaging, correlations and memory
International Nuclear Information System (INIS)
Wouters, Jeroen; Lucarini, Valerio
2012-01-01
We consider two weakly coupled systems and adopt a perturbative approach based on the Ruelle response theory to study their interaction. We propose a systematic way of parameterizing the effect of the coupling as a function of only the variables of a system of interest. Our focus is on describing the impacts of the coupling on the long term statistics rather than on the finite-time behavior. By direct calculation, we find that, at first order, the coupling can be surrogated by adding a deterministic perturbation to the autonomous dynamics of the system of interest. At second order, there are additionally two separate and very different contributions. One is a term taking into account the second-order contributions of the fluctuations in the coupling, which can be parameterized as a stochastic forcing with given spectral properties. The other one is a memory term, coupling the system of interest to its previous history, through the correlations of the second system. If these correlations are known, this effect can be implemented as a perturbation with memory on the single system. In order to treat this case, we present an extension to Ruelle's response theory able to deal with integral operators. We discuss our results in the context of other methods previously proposed for disentangling the dynamics of two coupled systems. We emphasize that our results do not rely on assuming a time scale separation, and, if such a separation exists, can be used equally well to study the statistics of the slow variables and that of the fast variables. By recursively applying the technique proposed here, we can treat the general case of multi-level systems
Heat flux and quantum correlations in dissipative cascaded systems
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.
Describing a Strongly Correlated Model System with Density Functional Theory.
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.
Quantum simulation of strongly correlated condensed matter systems
Hofstetter, W.; Qin, T.
2018-04-01
We review recent experimental and theoretical progress in realizing and simulating many-body phases of ultracold atoms in optical lattices, which gives access to analog quantum simulations of fundamental model Hamiltonians for strongly correlated condensed matter systems, such as the Hubbard model. After a general introduction to quantum gases in optical lattices, their preparation and cooling, and measurement techniques for relevant observables, we focus on several examples, where quantum simulations of this type have been performed successfully during the past years: Mott-insulator states, itinerant quantum magnetism, disorder-induced localization and its interplay with interactions, and topological quantum states in synthetic gauge fields.
Transfer of spectral weight in spectroscopies of correlated electron systems
International Nuclear Information System (INIS)
Rozenberg, M.J.; Kotliar, G.; Kajueter, H.
1996-01-01
We study the transfer of spectral weight in the photoemission and optical spectra of strongly correlated electron systems. Within the local impurity self-consistent approximation, that becomes exact in the limit of large lattice coordination, we consider and compare two models of correlated electrons, the Hubbard model and the periodic Anderson model. The results are discussed in regard to recent experiments. In the Hubbard model, we predict an anomalous enhancement optical spectral weight as a function of temperature in the correlated metallic state which is in qualitative agreement with optical measurements in V 2 O 3 . We argue that anomalies observed in the spectroscopy of the metal are connected to the proximity to a crossover region in the phase diagram of the model. In the insulating phase, we obtain excellent agreement with the experimental data, and present a detailed discussion on the role of magnetic frustration by studying the k-resolved single-particle spectra. The results for the periodic Anderson model are discussed in connection to recent experimental data of the Kondo insulators Ce 3 Bi 4 Pt 3 and FeSi. The model can successfully explain the thermal filling of the optical gap and the corresponding changes in the photoemission density of states. The temperature dependence of the optical sum rule is obtained, and its relevance to the interpretation of the experimental data discussed. Finally, we argue that the large scattering rate measured in Kondo insulators cannot be described by the periodic Anderson model. copyright 1996 The American Physical Society
White matter correlates of neuropsychological dysfunction in systemic lupus erythematosus.
Directory of Open Access Journals (Sweden)
Rex E Jung
Full Text Available Patients diagnosed with Systemic Lupus Erythematosus have similar levels of neuropsychological dysfunction (i.e., 20-50% as those with Neuropsychiatric Systemic Lupus Erythematosus (NPSLE. We hypothesized a gradient between cognition and white matter integrity, such that strongest brain-behavior relationships would emerge in NPSLE, intermediate in non-NPSLE, and minimal in controls. We studied thirty-one patients (16 non-NPSLE; 15 NPSLE, ranging in age from 18 to 59 years old (100% female, and eighteen age and gender matched healthy controls. DTI examinations were performed on a 1.5T scanner. A broad neuropsychological battery was administered, tapping attention, memory, processing speed, and executive functioning. The Total z-score consisted of the combined sum of all neuropsychological measures. In control subjects, we found no significant FA-Total z-score correlations. NPSLE, non-NPSLE, and control subjects differed significantly in terms of Total z-score (NPSLE = -2.25+/-1.77, non-NPSLE = -1.22+/-1.03, Controls = -0.10+/-.57; F = 13.2, p<.001. In non-NPSLE subjects, FA within the right external capsule was significantly correlated with Total z-score. In NPSLE subjects, the largest FA-Total z-score clusters were observed within the left anterior thalamic radiation and right superior longitudinal fasciculus. In subsequent analyses the largest number of significant voxels linked FA with the Processing Speed z-score in NPSLE. The current results reflect objective white matter correlates of neuropsychological dysfunction in both NPSLE and (to a lesser degree in non-NPSLE. non-NPSLE and NPSLE subjects did not differ significantly in terms of depression, as measured by the GDI; thus, previous hypotheses suggesting moderating effects of depression upon neuropsychological performance do not impact the current FA results.
A flexible time recording and time correlation analysis system
International Nuclear Information System (INIS)
Shenhav, N.J.; Leiferman, G.; Segal, Y.; Notea, A.
1983-01-01
A system was developed to digitize and record the time intervals between detection event pulses, feed to its input channels from a detection device. The accumulated data is transferred continuously in real time to a disc through a PDP 11/34 minicomputer. Even though the system was designed for a specific scope, i.e., the comparative study of passive neutron nondestructive assay methods, it can be characterized by its features as a general purpose time series recorder. The time correlation analysis is performed by software after completion of the data accumulation. The digitizing clock period is selectable and any value, larger than a minimum of 100 ns, may be selected. Bursts of up to 128 events with a frequency up to 10 MHz may be recorded. With the present recorder-minicomputer combination, the maximal average recording frequency is 40 kHz. (orig.)
Bound states in strongly correlated magnetic and electronic systems
International Nuclear Information System (INIS)
Trebst, S.
2002-02-01
A novel strong coupling expansion method to calculate two-particle spectra of quantum lattice models is developed. The technique can be used to study bosonic and fermionic models and in principle it can be applied to systems in any dimension. A number of strongly correlated magnetic and electronic systems are examined including the two-leg spin-half Heisenberg ladder, the dimerized Heisenberg chain with a frustrating next-nearest neighbor interaction, coupled Heisenberg ladders, and the one-dimensional Kondo lattice model. In the various models distinct bound states are found below the two-particle continuum. Quantitative calculations of the dispersion, coherence length and binding energy of these bound states are used to describe spectroscopic experiments on (Ca,La) 14 Cu 24 O 41 and NaV 2 O 5 . (orig.)
Clinical and MRI correlation in multiple system atrophy
Energy Technology Data Exchange (ETDEWEB)
Negoro, Kiyoshi; Morimatsu, Mitsunori (Yamaguchi Univ., Ube (Japan). School of Medicine)
1994-05-01
By using magnetic resonance imaging (MRI), we studied 11 patients with multiple system atrophy (MSA): 5 olivo-pontocerebellar atrophy (OPCA), 2 Shy-Drager syndrome (SDS), and 4 striatonigral degeneration (SND). The diagnoses of OPCA, SDS and SND were clinically made. The MR images were performed on 1.5 tesla MRI unit (Siemens Asahi Medical, Magnetom H15), using a T[sub 2]-weighted spin echo (SE) sequence (TR: 2000-3000 ms, TE: 80-90 ms), a T[sub 1]-weighted SE sequence (TR: 550, TE: 15), and a proton density-weighted (PD) SE sequence (TR: 2000-3000, TE: 12-22). In the patients with OPCA, MRI revealed cerebellar and brainstem atrophy and degeneration of pontine transverse fibers more marked than in the patients with SDS and SND. T[sub 2]-weighted images showed low intensity in posterolateral putamina in one OPCA patient and all of SDS and SND patients. PD images demonstrated the abnormal slit-like high signals in posterolateral putamina in three SND. The degree of cerebellar ataxia was not well correlated with cerebellar and brainstem atrophy and degeneration of pontine transverse fibers. There was a positive correlation between the atrophy of cerebellum and brainstem and the duration of cerebellar ataxia. In most of the patients with Parkinsonism, MRI demonstrated abnormal low signals in putamina on T[sub 2]-weighted images. There were positive correlations between the abnormal low signals putamina and the duration and severity of Parkinsonism. Though abnormal low signals in lateral putamina may be seen in normal aging and other disorders on T[sub 2]-weighted images, it is useful to evaluate Parkinsonism in MSA. We believe that the abnormal slit-like high signals in posterolateral putamina in MSA may suggest loss of neurons and gliosis. (author).
Preliminary Correlations for Remotely Piloted Aircraft Systems Sizing
Directory of Open Access Journals (Sweden)
Álvaro Gómez-Rodríguez
2018-01-01
Full Text Available The field of Remotely Piloted Aircraft Systems (RPAS is currently undergoing a noteworthy expansion. The diverse types of missions that these aircraft can accomplish, both in military and civil environments, have motivated an increase of interest in their study and applications. The methods chosen to develop this study are based on the statistical analysis of a database including numerous models of RPAS and the estimation of different correlations in order to develop a design method for rapid sizing of H-tail RPAS. Organizing the information of the database according to relevant characteristics, information relative to the state-of-the-art design tendencies can be extracted, which can serve to take decisions relative to the aerodynamic configuration or the power plant in the first phases of the design project. Furthermore, employing statistical correlations estimated from the database, a design method for rapid-sizing of H-tail RPAS has been conducted, which will be focused on the sizing of the wing and tail surfaces. The resulting method has been tested by applying it to an example case so as to validate the proposed procedure.
Correlation plot facility in the SLC control system
International Nuclear Information System (INIS)
Hendrickson, L.; Phinney, N.; Sanchez-Chopitea, L.
1991-05-01
The Correlation Plot facility is a powerful interactive tool for data acquisition and analysis throughout the SLC. A generalized interface allows the user to perform a wide variety of machine physics experiments without the need for specialized software. It has been used extensively during SLC commissioning and operation. The user may step one or two independent parameters such as magnet or feedback setpoints while measuring or calculating up to 160 others. Measured variables include all analog signals available to the control system as well as a variety of derived parameters such as beam size or emittance. Various fitting algorithms and display options are provided for data analysis. A software-callable interface is also provided. Applications based on this facility are used to phase klystrons, measure emittance and dispersion, minimize beam size at the interaction point and maintain beam collisions. 4 refs., 3 figs
Correlation Plot facility in the SLC control system
International Nuclear Information System (INIS)
Hendrickson, L.; Phinney, N.; Sanchez-Chopitea, L.; Clark, S.
1991-11-01
The Correlation Plot facility is a powerful interactive tool for data acquisition and analysis throughout the SLC. This generalized interface allows the user to perform a range of operations or machine physics experiments without the need for any specialized analysis software. The user may step one or more independent parameters, such as magnet or feedback setpoints, while measuring or calculating up to 160 other parameters. Measured variables include all analog signals available to the control system, as well as calculated parameters such as beam size, luminosity, or emittance. Various fitting algorithms and display options are provided. A software-callable interface has been provided so that a host of applications can call this package for analysis and display. Such applications regularly phase klystrons, measure emittance and dispersion, minimize beam size, and maintain beam collisions at the interaction point. 4 refs., 5 figs
Correlation Plot facility in the SLC control system
International Nuclear Information System (INIS)
Hendrickson, L.; Phinney, N.; Sachez-Chopitea, L.; Clark, S.
1992-01-01
The Correlation Plot facility is a powerful interactive tool for data acquisition and analysis throughout the SLC. This generalized interface allows the user to perform a range of operations or machine physics experiments without the need for any specialized analysis software. The user may step one or more independent parameters, such as magnet or feedback set points, while measuring or calculating up to 160 other parameters. Measured variables include all analog signals available to the control system, as well as calculated parameters such as beam size, luminosity, or emittance. Various fitting algorithms and display options are provided. A software-callable interface has been provided so that a host of applications can call this package for analysis and display. Such applications regularly phase klystrons, measure emittance and dispersion, minimize beam size, and maintain beam collisions at the interaction point. (author)
Non-equilibrium magnetic interactions in strongly correlated systems
Energy Technology Data Exchange (ETDEWEB)
Secchi, A., E-mail: a.secchi@science.ru.nl [Institute for Molecules and Materials, Radboud University Nijmegen, 6525 AJ Nijmegen (Netherlands); Brener, S.; Lichtenstein, A.I. [Institut für Theoretische Physik, Universitat Hamburg, Jungiusstraße 9, D-20355 Hamburg (Germany); Katsnelson, M.I. [Institute for Molecules and Materials, Radboud University Nijmegen, 6525 AJ Nijmegen (Netherlands)
2013-06-15
We formulate a low-energy theory for the magnetic interactions between electrons in the multi-band Hubbard model under non-equilibrium conditions determined by an external time-dependent electric field which simulates laser-induced spin dynamics. We derive expressions for dynamical exchange parameters in terms of non-equilibrium electronic Green functions and self-energies, which can be computed, e.g., with the methods of time-dependent dynamical mean-field theory. Moreover, we find that a correct description of the system requires, in addition to exchange, a new kind of magnetic interaction, that we name twist exchange, which formally resembles Dzyaloshinskii–Moriya coupling, but is not due to spin–orbit, and is actually due to an effective three-spin interaction. Our theory allows the evaluation of the related time-dependent parameters as well. -- Highlights: •We develop a theory for magnetism of strongly correlated systems out of equilibrium. •Our theory is suitable for laser-induced ultrafast magnetization dynamics. •We write time-dependent exchange parameters in terms of electronic Green functions. •We find a new magnetic interaction, a “twist exchange”. •We give general expressions for magnetic noise in itinerant-electron systems.
Precise timing correlation in telemetry recording and processing systems
Pickett, R. B.; Matthews, F. L.
1973-01-01
Independent PCM telemetry data signals received from missiles must be correlated to within + or - 100 microseconds for comparison with radar data. Tests have been conducted to determine RF antenna receiving system delays; delays associated with wideband analog tape recorders used in the recording, dubbing and repdocuing processes; and uncertainties associated with computer processed time tag data. Several methods used in the recording of timing are evaluated. Through the application of a special time tagging technique, the cumulative timing bias from all sources is determined and the bias removed from final data. Conclusions show that relative time differences in receiving, recording, playback and processing of two telemetry links can be accomplished with a + or - 4 microseconds accuracy. In addition, the absolute time tag error (with respect to UTC) can be reduced to less than 15 microseconds. This investigation is believed to be the first attempt to identify the individual error contributions within the telemetry system and to describe the methods of error reduction within the telemetry system and to describe the methods of error reduction and correction.
Digital optical correlator x-ray telescope alignment monitoring system
Lis, Tomasz; Gaskin, Jessica; Jasper, John; Gregory, Don A.
2018-01-01
The High-Energy Replicated Optics to Explore the Sun (HEROES) program is a balloon-borne x-ray telescope mission to observe hard x-rays (˜20 to 70 keV) from the sun and multiple astrophysical targets. The payload consists of eight mirror modules with a total of 114 optics that are mounted on a 6-m-long optical bench. Each mirror module is complemented by a high-pressure xenon gas scintillation proportional counter. Attached to the payload is a camera that acquires star fields and then matches the acquired field to star maps to determine the pointing of the optical bench. Slight misalignments between the star camera, the optical bench, and the telescope elements attached to the optical bench may occur during flight due to mechanical shifts, thermal gradients, and gravitational effects. These misalignments can result in diminished imaging and reduced photon collection efficiency. To monitor these misalignments during flight, a supplementary Bench Alignment Monitoring System (BAMS) was added to the payload. BAMS hardware comprises two cameras mounted directly to the optical bench and rings of light-emitting diodes (LEDs) mounted onto the telescope components. The LEDs in these rings are mounted in a predefined, asymmetric pattern, and their positions are tracked using an optical/digital correlator. The BAMS analysis software is a digital adaption of an optical joint transform correlator. The aim is to enhance the observational proficiency of HEROES while providing insight into the magnitude of mechanically and thermally induced misalignments during flight. Results from a preflight test of the system are reported.
Lactose and ''tris'' lyoluminescence dosimetry systems and ESR correlation studies
International Nuclear Information System (INIS)
Oommen, I.K.; Nambi, K.S.V.; Sengupta, S.; Rao, T.K.G.; Ravikumar, M.
1989-01-01
Lyoluminescence (LL) dosimeters have been developed using lactose monohydrate (disaccharide) and tris(hydroxymethyl)aminomethane (''Tris'') systems and attempts have been made to understand the LL mechanism through ESR correlation studies. Tris LL dosimeter has a γ-ray sensitivity with a linear response in the absorbed-dose range 0.05-200 Gy (5-2 x 10 4 rad), while the lactose response extends to a higher range from 1 to 10 4 Gy (10 2 -10 6 rad). The LL output of lactose and Tris did not show any appreciable decay for a period of 6 months after irradiation. ESR measurements show that free-radical concentration in both the systems increases with γ-ray dose in the range 10 2 -10 5 Gy. The minimum dose required to measure the radiation-induced ESR signal for Tris is ∼ 500 Gy, the dose at which the LL output saturates, while lactose shows a radiation-induced ESR signal right at the minimum dose where LL could be detected. The estimated spin density on the radical carbon atom is 0.7. ESR signal stabilities of lactose and Tris were also studied. Lactose did not show any appreciable ESR decay for a period of 3 months after irradiation, while, for Tris, one of the radicals showed a decay of 45% for the same period. (author)
PREFACE: International Conference on Strongly Correlated Electron Systems (SCES 2011)
Littlewood, P. B.; Lonzarich, G. G.; Saxena, S. S.; Sutherland, M. L.; Sebastian, S. E.; Artacho, E.; Grosche, F. M.; Hadzibabic, Z.
2012-11-01
The Strongly Correlated Electron Systems Conference (SCES) 2011, was held from 29 August-3 September 2011, in Cambridge, UK. SCES'2011 was dedicated to 100 years of superconductivity and covered a range of topics in the area of strongly correlated systems. The correlated electronic and magnetic materials featured include f-electron based heavy fermion intermetallics and d-electron based transition metal compounds. The meeting welcomed to Cambridge 657 participants from 23 countries, who presented 127 talks (including 16 plenary, 57 invited, and 54 contributed) and 736 posters in 40 sessions over five full days of meetings. This proceedings volume contains papers reporting on the science presented at the meeting. This work deepens our understanding of the rich physical phenomena that arise from correlation effects. Strongly correlated systems are known for their remarkable array of emergent phenomena: the traditional subjects of superconductivity, magnetism and metal-insulator transitions have been joined by non-Fermi liquid phenomena, topologically protected quantum states, atomic and photonic gases, and quantum phase transitions. These are some of the most challenging and interesting phenomena in science. As well as the science driver, there is underlying interest in energy-dense materials, which make use of 'small' electrons packed to the highest possible density. These are by definition 'strongly correlated'. For example: good photovoltaics must be efficient optical absorbers, which means that photons will generate tightly bound electron-hole pairs (excitons) that must then be ionised at a heterointerface and transported to contacts; efficient solid state refrigeration depends on substantial entropy changes in a unit cell, with large local electrical or magnetic moments; efficient lighting is in a real sense the inverse of photovoltaics; the limit of an efficient battery is a supercapacitor employing mixed valent ions; fuel cells and solar to fuel conversion
Transport through correlated systems with density functional theory.
Kurth, S; Stefanucci, G
2017-10-18
We present recent advances in density functional theory (DFT) for applications in the field of quantum transport, with particular emphasis on transport through strongly correlated systems. We review the foundations of the popular Landauer-Büttiker(LB) + DFT approach. This formalism, when using approximations to the exchange-correlation (xc) potential with steps at integer occupation, correctly captures the Kondo plateau in the zero bias conductance at zero temperature but completely fails to capture the transition to the Coulomb blockade (CB) regime as the temperature increases. To overcome the limitations of LB + DFT, the quantum transport problem is treated from a time-dependent (TD) perspective using TDDFT, an exact framework to deal with nonequilibrium situations. The steady-state limit of TDDFT shows that in addition to an xc potential in the junction, there also exists an xc correction to the applied bias. Open shell molecules in the CB regime provide the most striking examples of the importance of the xc bias correction. Using the Anderson model as guidance we estimate these corrections in the limit of zero bias. For the general case we put forward a steady-state DFT which is based on one-to-one correspondence between the pair of basic variables, steady density on and steady current across the junction and the pair local potential on and bias across the junction. Like TDDFT, this framework also leads to both an xc potential in the junction and an xc correction to the bias. Unlike TDDFT, these potentials are independent of history. We highlight the universal features of both xc potential and xc bias corrections for junctions in the CB regime and provide an accurate parametrization for the Anderson model at arbitrary temperatures and interaction strengths, thus providing a unified DFT description for both Kondo and CB regimes and the transition between them.
Quantum phase transitions of strongly correlated electron systems
International Nuclear Information System (INIS)
Imada, Masatoshi
1998-01-01
Interacting electrons in solids undergo various quantum phase transitions driven by quantum fluctuations. The quantum transitions take place at zero temperature by changing a parameter to control quantum fluctuations rather than thermal fluctuations. In contrast to classical phase transitions driven by thermal fluctuations, the quantum transitions have many different features where quantum dynamics introduces a source of intrinsic fluctuations tightly connected with spatial correlations and they have been a subject of recent intensive studies as we see below. Interacting electron systems cannot be fully understood without deep analyses of the quantum phase transitions themselves, because they are widely seen and play essential roles in many phenomena. Typical and important examples of the quantum phase transitions include metal-insulator transitions, (2, 3, 4, 5, 6, 7, 8, 9) metal-superconductor transitions, superconductor-insulator transitions, magnetic transitions to antiferromagnetic or ferromagnetic phases in metals as well as in Mott insulators, and charge ordering transitions. Here, we focus on three different types of transitions
Data analysis of backscattering LIDAR system correlated with meteorological data
International Nuclear Information System (INIS)
Uehara, Sandro Toshio
2009-01-01
In these last years, we had an increase in the interest in the monitoring of the effect of the human activity being on the atmosphere and the climate in the planet. The remote sensing techniques has been used in many studies, also related the global changes. A backscattering LIDAR system, the first of this kind in Brazil, has been used to provide the vertical profile of the aerosol backscatter coefficient at 532 nm up to an altitude of 4-6 km above sea level. In this study, data has was collected in the year of 2005. These data had been correlated with data of solar photometer CIMEL and also with meteorological data. The main results had indicated to exist a standard in the behavior of these meteorological data and the vertical distribution of the extinction coefficient gotten through LIDAR. In favorable periods of atmospheric dispersion, that is, rise of the temperature of associated air the fall of relative humidity, increase of the atmospheric pressure and low ventilation tax, was possible to determine with good precision the height of the Planetary Boundary Layer, as much through the vertical profile of the extinction coefficient how much through the technique of the vertical profile of the potential temperature. The technique LIDAR showed to be an important tool in the determination of the thermodynamic structure of the atmosphere, assisting to characterize the evolution of the CLP throughout the day, which had its good space and secular resolution. (author)
Non perturbative aspects of strongly correlated electron systems
International Nuclear Information System (INIS)
Controzzi, D.
2000-01-01
In this thesis we report some selected works on Strongly Correlated Electron Systems. A common ingredient of these works is the use of non-perturbative techniques available in low dimensions. In the first part we use the Bethe Ansatz to study some properties of two families of integrable models introduced by Fateev. We calculate the Thermodynamics of the models and show how they can be interpreted as effective Landau-Ginzburg theories for coupled two-dimensional superconductors interacting with an insulating substrate. This allows us to study exactly the dependence of the critical temperature on the thickness of the insulating layer, and on the interaction between the order parameters of two different superconducting planes. In the second part of the thesis we study the optical conductivity of the sine-Gordon model using the Form Factor method and Conformal Perturbation Theory. This allows us to develop, for the first time, a complete theory of the optical conductivity of one-dimensional Mott insulators, in the Quantum Field Theory limit. (author)
Theory of L -edge spectroscopy of strongly correlated systems
Lüder, Johann; Schött, Johan; Brena, Barbara; Haverkort, Maurits W.; Thunström, Patrik; Eriksson, Olle; Sanyal, Biplab; Di Marco, Igor; Kvashnin, Yaroslav O.
2017-12-01
X-ray absorption spectroscopy measured at the L edge of transition metals (TMs) is a powerful element-selective tool providing direct information about the correlation effects in the 3 d states. The theoretical modeling of the 2 p →3 d excitation processes remains to be challenging for contemporary ab initio electronic structure techniques, due to strong core-hole and multiplet effects influencing the spectra. In this work, we present a realization of the method combining the density-functional theory with multiplet ligand field theory, proposed in Haverkort et al. [Phys. Rev. B 85, 165113 (2012), 10.1103/PhysRevB.85.165113]. In this approach, a single-impurity Anderson model (SIAM) is constructed, with almost all parameters obtained from first principles, and then solved to obtain the spectra. In our implementation, we adopt the language of the dynamical mean-field theory and utilize the local density of states and the hybridization function, projected onto TM 3 d states, in order to construct the SIAM. The developed computational scheme is applied to calculate the L -edge spectra for several TM monoxides. A very good agreement between the theory and experiment is found for all studied systems. The effect of core-hole relaxation, hybridization discretization, possible extensions of the method as well as its limitations are discussed.
Conditions for monogamy of quantum correlations in multipartite systems
Energy Technology Data Exchange (ETDEWEB)
Kumar, Asutosh, E-mail: asukumar@hri.res.in
2016-09-07
Highlights: • Monogamy of quantum correlations. • Monogamous quantum correlation measures remain so on raising of power. • Non-monogamous quantum correlations remain so on lowering of power. • Monogamy of a convex quantum correlation measure for an arbitrary multipartite pure quantum state leads to its monogamy for the mixed states. • A new monogamy inequality for quantum correlations, stronger than the standard one. - Abstract: Monogamy of quantum correlations is a vibrant area of research because of its potential applications in several areas in quantum information ranging from quantum cryptography to co-operative phenomena in many-body physics. In this paper, we investigate conditions under which monogamy is preserved for functions of quantum correlation measures. We prove that a monogamous measure remains monogamous on raising its power, and a non-monogamous measure remains non-monogamous on lowering its power. We also prove that monogamy of a convex quantum correlation measure for arbitrary multipartite pure quantum state leads to its monogamy for mixed states in the same Hilbert space. Monogamy of squared negativity for mixed states and that of entanglement of formation follow as corollaries of our results.
Aspects of Strongly Correlated Many-Body Fermi Systems
Porter, William J., III
A, by now, well-known signal-to-noise problem plagues Monte Carlo calculations of quantum-information-theoretic observables in systems of interacting fermions, particularly the Renyi entanglement entropies Sn, even in many cases where the infamous sign problem does not appear. Several methods have been put forward to circumvent this affliction including ensemble-switching techniques using auxiliary partition-function ratios. This dissertation presents an algorithm that modifies the recently proposed free-fermion decomposition in an essential way: we incorporate the entanglement-sensitive correlations directly into the probability measure in a natural way. Implementing this algorithm, we demonstrate that it is compatible with the hybrid Monte Carlo algorithm, the workhorse of the lattice quantum chromodynamics community and an essential tool for studying gauge theories that contain dynamical fermions. By studying a simple one-dimensional Hubbard model, we demonstrate that our method does not exhibit the same debilitating numerical difficulties that naive attempts to study entanglement often encounter. Following that, we illustrate some key probabilistic insights, using intuition derived from the previous method and its successes to construct a simpler, better behaved, and more elegant algorithm. Using this method, in combination with new identities which allow us to avoid seemingly necessary numerical difficulties, the inversion of the restricted one-body density matrices, we compute high order Renyi entropies and perform a thorough comparison to this new algorithm's predecessor using the Hubbard model mentioned before. Finally, we characterize non-perturbatively the Renyi entropies of degree n = 2,3,4, and 5 of three-dimensional, strongly coupled many-fermion systems in the scale-invariant regime of short interaction range and large scattering length, i.e. in the unitary limit using the algorithms detailed herein. We also detail an exact, few-body projective method
Advanced cluster methods for correlated-electron systems
Energy Technology Data Exchange (ETDEWEB)
Fischer, Andre
2015-04-27
In this thesis, quantum cluster methods are used to calculate electronic properties of correlated-electron systems. A special focus lies in the determination of the ground state properties of a 3/4 filled triangular lattice within the one-band Hubbard model. At this filling, the electronic density of states exhibits a so-called van Hove singularity and the Fermi surface becomes perfectly nested, causing an instability towards a variety of spin-density-wave (SDW) and superconducting states. While chiral d+id-wave superconductivity has been proposed as the ground state in the weak coupling limit, the situation towards strong interactions is unclear. Additionally, quantum cluster methods are used here to investigate the interplay of Coulomb interactions and symmetry-breaking mechanisms within the nematic phase of iron-pnictide superconductors. The transition from a tetragonal to an orthorhombic phase is accompanied by a significant change in electronic properties, while long-range magnetic order is not established yet. The driving force of this transition may not only be phonons but also magnetic or orbital fluctuations. The signatures of these scenarios are studied with quantum cluster methods to identify the most important effects. Here, cluster perturbation theory (CPT) and its variational extention, the variational cluster approach (VCA) are used to treat the respective systems on a level beyond mean-field theory. Short-range correlations are incorporated numerically exactly by exact diagonalization (ED). In the VCA, long-range interactions are included by variational optimization of a fictitious symmetry-breaking field based on a self-energy functional approach. Due to limitations of ED, cluster sizes are limited to a small number of degrees of freedom. For the 3/4 filled triangular lattice, the VCA is performed for different cluster symmetries. A strong symmetry dependence and finite-size effects make a comparison of the results from different clusters difficult
Quantum phase transition in strongly correlated many-body system
You, Wenlong
The past decade has seen a substantial rejuvenation of interest in the study of quantum phase transitions (QPTs), driven by experimental advance on the cuprate superconductors, the heavy fermion materials, organic conductors, Quantum Hall effect, Fe-As based superconductors and other related compounds. It is clear that strong electronic interactions play a crucial role in the systems of current interest, and simple paradigms for the behavior of such systems near quantum critical points remain unclear. Furthermore, the rapid progress in Feshbach resonance and optical lattice provides a flexible platform to study QPT. Quantum Phase Transition (QPT) describes the non-analytic behaviors of the ground-state properties in a many-body system by varying a physical parameter at absolute zero temperature - such as magnetic field or pressure, driven by quantum fluctuations. Such quantum phase transitions can be first-order phase transition or continuous. The phase transition is usually accompanied by a qualitative change in the nature of the correlations in the ground state, and describing this change shall clearly be one of our major interests. We address this issue from three prospects in a few strong correlated many-body systems in this thesis, i.e., identifying the ordered phases, studying the properties of different phases, characterizing the QPT points. In chapter 1, we give an introduction to QPT, and take one-dimensional XXZ model as an example to illustrate the QPT therein. Through this simple example, we would show that when the tunable parameter is varied, the system evolves into different phases, across two quantum QPT points. The distinct phases exhibit very different behaviors. Also a schematic phase diagram is appended. In chapter 2, we are engaged in research on ordered phases. Originating in the work of Landau and Ginzburg on second-order phase transition, the spontaneous symmetry breaking induces nonzero expectation of field operator, e.g., magnetization M
Excitonic condensation in systems of strongly correlated electrons
Czech Academy of Sciences Publication Activity Database
Kuneš, Jan
2015-01-01
Roč. 27, č. 33 (2015), s. 333201 ISSN 0953-8984 Institutional support: RVO:68378271 Keywords : electronic correlations * exciton * Bose-Einstein condensation Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.209, year: 2015
Correlation between duodenogastric reflux and symptoms of digestive system diseases
International Nuclear Information System (INIS)
Leja, M.; Reinholds, E.; Brezinskis, G.; Aboltins, A.; Lejnieks, A.
2004-01-01
The symptoms of digestive origin potentially indicative for duodenogastric reflux (DGR) have been compared to the results obtained by scintigraphic method, elaborated by the group of authors. The symptoms were registred bu using a specially elaborated questionnaire according to preliminary determined intervals of time with respect to the scintigraphic investigation. No correlation was found between DGR and the following symptoms: nausea, vomiting, regurgitation with sour and bitter content, belching, heartburn, burning sensation in the epigastric area, early satiety, flatulence, constipation, dyspepsia and abdominal pain. Diarrhoea in the morning of the investigation and month prior to the investigation was statistically significantly correlating to DGR, while no correlation was confirmed to the symptom a day and a week prior to the investigation. Bittertaste in the mouth had the best correlation to DGR in all the analysed intervals. The conclusion is made that bitter taste in the mouth is the best correlating symptom for DGR, still the low sensitivity and low positive and negative predictive values of the symptom does not make it a useful guide for symptom-based diagnosis of DGR
Transport-induced correlations in weakly interacting systems
International Nuclear Information System (INIS)
Bunin, Guy; Kafri, Yariv; Podolsky, Daniel; Lecomte, Vivien; Polkovnikov, Anatoli
2013-01-01
We study spatial correlations in the transport of energy between two baths at different temperatures. To do this, we introduce a minimal model in which energy flows from one bath to another through two subsystems. We show that the transport-induced energy correlations between the two subsystems are of the same order as the energy fluctuations within each subsystem. The correlations can be either positive or negative and we give bounds on their values which are associated with a dynamic energy scale. The different signs originate as a competition between fluctuations generated near the baths and fluctuations of the current between the two subsystems. This interpretation sheds light on known results for spatially-dependent heat and particle conduction models. (paper)
SEPHIS and the distribution coefficients correlation in the IMPUREX system
International Nuclear Information System (INIS)
Andaur Iturrieta, Claudio
1997-01-01
The reprocessing of spent nuclear fuels by the IMPUREX process consists in uranium selective extraction, originally in aqueous nitric solution, by action of the tributyl phosphate (TBP) present in an organic phase that circulates at countercurrent of the aqueous one. In the study of such process, it is necessary to use the correlations that allows to predict the concentrations of the solutes in the equilibrium, both in the aqueous phase and in the organic one, given as data the ruling operation conditions (temperature, TBP concentration and acidity). A correlation of this kind is the Groenier-Rainey-Watson, which is forming part of the code of the SEPHIS simulation program. In the present work it is analyzed the behavior of this correlation contrasting the predicted values with experimental ones
Coulomb correlation effects in YBaCuO system
International Nuclear Information System (INIS)
Costa-quintana, J.; Lopez-Aguilar, F.; Munoz, J.S.; Sanchez, A.; Balle, S.
1989-01-01
In this work, the authors apply a mean field potential deduced from the multiband Hubbard Hamiltonian in order to obtain the lower and upper strongly correlated bands. They have obtained the total and partial density of states for U d = O and U d = 4 eV. The results show that the density of states calculated with U d = 4 eV at E F is lesser than that obtained with U d = 0. A small peak above E F arising from the strong correlated bands appears in the dDOS calculated with U d = 4 eV and this is in agreement with the experimental data
Molecular photoionization studies of nucleobases and correlated systems
Energy Technology Data Exchange (ETDEWEB)
Poliakoff, Erwin D. [Louisiana State Univ., Baton Rouge, LA (United States)
2015-03-11
We proposed molecular photoionization studies in order to probe correlated events in fundamental scattering phenomena. In particular, we suggested that joint theoretical-experimental studies would provide a window into the microscopic aspects that are of central importance in AMO and chemical physics generally, and would generate useful data for wide array of important DOE topics, such as ultrafast dynamics, high harmonic generation, and probes of nonadiabatic processes. The unifying theme is that correlations between electron scattering dynamics and molecular geometry highlight inherently molecular aspects of the photoelectron behavior.
Quantum correlations in a bipartite multiqubit spin ring system
International Nuclear Information System (INIS)
Doronin, S I; Fel’dman, E B; Kuznetsova, E I
2015-01-01
We consider a spin ring with an arbitrary number of spins on the ring and one spin in its center in a strong external magnetic field. The spins on the ring are connected by the secular dipole–dipole interactions and interact with the central spin through the Heisenberg zz-interaction. We show that the quantum discord, describing quantum correlations between the ring and the central spin, can be obtained analytically for an arbitrary number of the spins in the high-temperature approximation. We demonstrate the evolution of quantum correlations at different numbers of the spins. The contributions of longitudinal and transversal spin interactions to the quantum discord are discussed. (paper)
Magneto-structural correlations in exchange coupled systems
International Nuclear Information System (INIS)
Willett, R.D.; Gatteschi, D.; Kahn, O.
1985-01-01
This book contains 19 chapters. Some of the chapter titles are: Optical Spectroscophy; The Basis of Spin-Hamiltonian Theory; Inelastic Neutorn Scattering From Clusters; Magneto-structural Correlations in Bioinorganic Chemistry; and Magnetic Exchange Interactions Propagated by Multi-Atom Bridges
Quantification of correlations in quantum many-particle systems
Czech Academy of Sciences Publication Activity Database
Byczuk, K.; Kuneš, Jan; Hofstetter, W.; Vollhardt, D.
2012-01-01
Roč. 108, č. 8 (2012), "087004-1"-"087004-5" ISSN 0031-9007 Institutional research plan: CEZ:AV0Z10100521 Keywords : electronic correlations * entropy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 7.943, year: 2012 http://link.aps.org/doi/10.1103/PhysRevLett.108.087004
Selective correlations in finite quantum systems and the Desargues property
Lei, C.; Vourdas, A.
2018-06-01
The Desargues property is well known in the context of projective geometry. An analogous property is presented in the context of both classical and Quantum Physics. In a classical context, the Desargues property implies that two logical circuits with the same input show in their outputs selective correlations. In general their outputs are uncorrelated, but if the output of one has a particular value, then the output of the other has another particular value. In a quantum context, the Desargues property implies that two experiments each of which involves two successive projective measurements have selective correlations. For a particular set of projectors, if in one experiment the second measurement does not change the output of the first measurement, then the same is true in the other experiment.
Coulomb correlation effects in YBaCuO system
Energy Technology Data Exchange (ETDEWEB)
Costa-Quintana, J; Lopez-Aguilar, F; Munoz, J S; Sanchez, A [Dept. de Fisica, Grupo de Electromagnetismo, Univ. Autonoma de Barcelona (Spain); Balle, S [Dept. de Fisica, Univ. de les Illes Balears, Palma de Mallorca (Spain)
1989-12-01
In this work, we apply a mean field potential deduced from the multiband Hubbard hamiltonian in order to obtain the lower and upper strongly correlated bands. We have obtained the total and partial density of states for U{sub d} = 0 and U{sub d} = 4 eV. The results show that the density of states calculated with U{sub d} = 4 eV at E{sub F} is lesser than that obtained with U{sub d} = 0. A small peak above E{sub F} arising from the strong correlated bands appears in the dDOS calculated with U{sub d} = 4 eV and this is in agreement with the experimental data. (orig.).
Towards a large deviation theory for strongly correlated systems
International Nuclear Information System (INIS)
Ruiz, Guiomar; Tsallis, Constantino
2012-01-01
A large-deviation connection of statistical mechanics is provided by N independent binary variables, the (N→∞) limit yielding Gaussian distributions. The probability of n≠N/2 out of N throws is governed by e −Nr , r related to the entropy. Large deviations for a strong correlated model characterized by indices (Q,γ) are studied, the (N→∞) limit yielding Q-Gaussians (Q→1 recovers a Gaussian). Its large deviations are governed by e q −Nr q (∝1/N 1/(q−1) , q>1), q=(Q−1)/(γ[3−Q])+1. This illustration opens the door towards a large-deviation foundation of nonextensive statistical mechanics. -- Highlights: ► We introduce the formalism of relative entropy for a single random binary variable and its q-generalization. ► We study a model of N strongly correlated binary random variables and their large-deviation probabilities. ► Large-deviation probability of strongly correlated model exhibits a q-exponential decay whose argument is proportional to N, as extensivity requires. ► Our results point to a q-generalized large deviation theory and suggest a large-deviation foundation of nonextensive statistical mechanics.
Accurate correlation energies in one-dimensional systems from small system-adapted basis functions
Baker, Thomas E.; Burke, Kieron; White, Steven R.
2018-02-01
We propose a general method for constructing system-dependent basis functions for correlated quantum calculations. Our construction combines features from several traditional approaches: plane waves, localized basis functions, and wavelets. In a one-dimensional mimic of Coulomb systems, it requires only 2-3 basis functions per electron to achieve high accuracy, and reproduces the natural orbitals. We illustrate its effectiveness for molecular energy curves and chains of many one-dimensional atoms. We discuss the promise and challenges for realistic quantum chemical calculations.
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.
Some Applications of Holography to Study Strongly Correlated Systems
Directory of Open Access Journals (Sweden)
Bhatnagar Neha
2018-01-01
Full Text Available 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.
A Correlated Model for Evaluating Performance and Energy of Cloud System Given System Reliability
Directory of Open Access Journals (Sweden)
Hongli Zhang
2015-01-01
Full Text Available The serious issue of energy consumption for high performance computing systems has attracted much attention. Performance and energy-saving have become important measures of a computing system. In the cloud computing environment, the systems usually allocate various resources (such as CPU, Memory, Storage, etc. on multiple virtual machines (VMs for executing tasks. Therefore, the problem of resource allocation for running VMs should have significant influence on both system performance and energy consumption. For different processor utilizations assigned to the VM, there exists the tradeoff between energy consumption and task completion time when a given task is executed by the VMs. Moreover, the hardware failure, software failure and restoration characteristics also have obvious influences on overall performance and energy. In this paper, a correlated model is built to analyze both performance and energy in the VM execution environment given the reliability restriction, and an optimization model is presented to derive the most effective solution of processor utilization for the VM. Then, the tradeoff between energy-saving and task completion time is studied and balanced when the VMs execute given tasks. Numerical examples are illustrated to build the performance-energy correlated model and evaluate the expected values of task completion time and consumed energy.
Similarity of fluctuations in correlated systems: The case of seismicity
International Nuclear Information System (INIS)
Varotsos, P.A.; Sarlis, N.V.; Tanaka, H.K.; Skordas, E.S.
2005-01-01
We report a similarity of fluctuations in equilibrium critical phenomena and nonequilibrium systems, which is based on the concept of natural time. The worldwide seismicity as well as that of the San Andreas fault system and Japan are analyzed. An order parameter is chosen and its fluctuations relative to the standard deviation of the distribution are studied. We find that the scaled distributions fall on the same curve, which interestingly exhibits, over four orders of magnitude, features similar to those in several equilibrium critical phenomena (e.g., two-dimensional Ising model) as well as in nonequilibrium systems (e.g., three-dimensional turbulent flow)
Neurofunctional systems. 3D reconstructions with correlated neuroimaging
International Nuclear Information System (INIS)
Kretschmann, H.J.; Fiekert, W.; Gerke, M.; Vogt, H.; Weirich, D.; Wesemann, M.; Weinrich, W.
1998-01-01
This book introduces, for the first time, computer-generated images of the neurofunctional systems of the human brain. These images are more accurate than drawings. The main views presented are of the medial lemniscus system, auditory system, visual system, basal ganglia, corticospinal system, and the limbic system. The arteries and sulci of the cerebral hemispheres are also illustrated by computer. These images provide a three-dimensional orientation of the intracranial space and help, for example, to assess vascular functional disturbance of the brain. Clinicians will find these images valuable for the spatial interpretation of magnetic resonance (MR), computed tomography (CT), and positron emission tomography (PET) images since many neurofunctional systems cannot be visualized as isolated structures in neuroimaging. Computer-assisted surface reconstructions of the neurofunctional systems and the cerebral arteries serve as a basis for constructing these computer-generated images. The surface reconstructions are anatomically realistic having been created from brain sections with minimal deformations. The method of computer graphics, known as ray tracing, produces digital images form these reconstructions. The computer-generated methods are explained. The computer-generated images are accompanied by illustrations and texts on neuroanatomy and clinical practice. The neurofunctional systems of the human brain are also shown in sections so that the reader can mentally reconstruct the neurofunctional systems, thus facilitating the transformation of information into textbooks and atlantes of MR and CT imaging. The aim of this book is acquaint the reader with the three-dimensional aspects of the neurofunctional systems and the cerebral arteries of the human brain using methods of computer graphics. Computer scientists and those interested in this technique are provided with basic neuroanatomic and neurofunctional information. Physicians will have a clearer understanding
Neurofunctional systems. 3D reconstructions with correlated neuroimaging
Energy Technology Data Exchange (ETDEWEB)
Kretschmann, H.J.; Fiekert, W.; Gerke, M.; Vogt, H.; Weirich, D.; Wesemann, M. [Medizinische Hochschule Hannover (Germany). Abt. Neuroanatomie; Weinrich, W. [Staedtisches Krankenhaus Nordstadt, Hannover (Germany). Abt. fuer Neurologie
1998-12-31
This book introduces, for the first time, computer-generated images of the neurofunctional systems of the human brain. These images are more accurate than drawings. The main views presented are of the medial lemniscus system, auditory system, visual system, basal ganglia, corticospinal system, and the limbic system. The arteries and sulci of the cerebral hemispheres are also illustrated by computer. These images provide a three-dimensional orientation of the intracranial space and help, for example, to assess vascular functional disturbance of the brain. Clinicians will find these images valuable for the spatial interpretation of magnetic resonance (MR), computed tomography (CT), and positron emission tomography (PET) images since many neurofunctional systems cannot be visualized as isolated structures in neuroimaging. Computer-assisted surface reconstructions of the neurofunctional systems and the cerebral arteries serve as a basis for constructing these computer-generated images. The surface reconstructions are anatomically realistic having been created from brain sections with minimal deformations. The method of computer graphics, known as ray tracing, produces digital images form these reconstructions. The computer-generated methods are explained. The computer-generated images are accompanied by illustrations and texts on neuroanatomy and clinical practice. The neurofunctional systems of the human brain are also shown in sections so that the reader can mentally reconstruct the neurofunctional systems, thus facilitating the transformation of information into textbooks and atlantes of MR and CT imaging. The aim of this book is acquaint the reader with the three-dimensional aspects of the neurofunctional systems and the cerebral arteries of the human brain using methods of computer graphics. Computer scientists and those interested in this technique are provided with basic neuroanatomic and neurofunctional information. Physicians will have a clearer understanding
The elimination of singularities in pair correlation functions of a multicomponent liquid system
International Nuclear Information System (INIS)
Vasil'jev, O.M.; Chalij, O.V.
2004-01-01
In this paper we propose a method that allows to find nonsingular expressions for pair correlation functions of a multicomponent liquid system. The nature of the method deals with using integral and differential Ornstein-Zernike equations for finding asymptotic expressions for pair correlation functions and their subsequent precision. The obtained results are analyzed taking into account their possible applicability for studying the correlative behaviour of multicomponent liquid systems
A perturbation method in strongly correlated fermion systems
International Nuclear Information System (INIS)
Keiter, H.; Oberbach, S.; Kilic, S.
1998-01-01
We present a new expression for the grand partition function of a many-body system which contains a generalized Feenberg energy formula. In addition a form of the momentum distribution function of the Luttinger model is derived and non Fermi liquid behaviour is demonstrated. (Copyright (1998) World Scientific Publishing Co. Pte. Ltd)
Magnetic interactions in strongly correlated systems: Spin and orbital contributions
Energy Technology Data Exchange (ETDEWEB)
Secchi, A., E-mail: a.secchi@science.ru.nl [Radboud University, Institute for Molecules and Materials, 6525 AJ Nijmegen (Netherlands); Lichtenstein, A.I. [Universitat Hamburg, Institut für Theoretische Physik, Jungiusstraße 9, D-20355 Hamburg (Germany); Katsnelson, M.I. [Radboud University, Institute for Molecules and Materials, 6525 AJ Nijmegen (Netherlands)
2015-09-15
We present a technique to map an electronic model with local interactions (a generalized multi-orbital Hubbard model) onto an effective model of interacting classical spins, by requiring that the thermodynamic potentials associated to spin rotations in the two systems are equivalent up to second order in the rotation angles, when the electronic system is in a symmetry-broken phase. This allows to determine the parameters of relativistic and non-relativistic magnetic interactions in the effective spin model in terms of equilibrium Green’s functions of the electronic model. The Hamiltonian of the electronic system includes, in addition to the non-relativistic part, relativistic single-particle terms such as the Zeeman coupling to an external magnetic field, spin–orbit coupling, and arbitrary magnetic anisotropies; the orbital degrees of freedom of the electrons are explicitly taken into account. We determine the complete relativistic exchange tensors, accounting for anisotropic exchange, Dzyaloshinskii–Moriya interactions, as well as additional non-diagonal symmetric terms (which may include dipole–dipole interaction). The expressions of all these magnetic interactions are determined in a unified framework, including previously disregarded features such as the vertices of two-particle Green’s functions and non-local self-energies. We do not assume any smallness in spin–orbit coupling, so our treatment is in this sense exact. Finally, we show how to distinguish and address separately the spin, orbital and spin–orbital contributions to magnetism, providing expressions that can be computed within a tight-binding Dynamical Mean Field Theory.
Correlated electron systems studied by μSR technique
International Nuclear Information System (INIS)
Amato, A.
1995-01-01
Recent muon spin relaxation and rotation experiments in heavy-fermion compounds aimed at investigating the microscopic co-existence as well as the interplay between magnetism and superconductivity are briefly presented. Relevant properties of the two systems UPd 2 Al 3 and CeCu 2 Si 2 are discussed and utilized to point out the lack of a universal picture for the heavy-fermion superconductors. The search for weak magnetism phenomena in the heavy-fermion compounds is illustrated with new examples and its possible origins are briefly surveyed. ((orig.))
Heavy fermions and other highly correlated electron systems
International Nuclear Information System (INIS)
Schlottmann, P.
1991-01-01
In this paper I given a brief summary of the achievements grouped under three main headings, namely (1) heavy-fermion, mixed-valence and Kondo systems, (2) the n-channel Kondo problem and applications, and (3) one-dimensional conductors and antiferromagnets. The list of published papers and preprints is attached to the report, as well as a list of abstracts submitted to Conferences. All these papers are new in the sense that none of them was listed in the final technical report of grant DE-FG02-87ER45333
System Design, Implementation, and Evaluation of the Optical Broadband Correlator
1994-09-20
shear-mode TeO2 , Model No. N45075-6-20, manufactured by Newport Electro- Optic Systems with a length of 75 pjs, acoustic direction 1110], optical...optical aperture (or useful length) TOA of our cells are shown in Table 3. The Bragg cells are shear-mode TeO2 , Model No. N45075-6-20, manufactured by...focusing or integrating (Fourier transform) lens is a laser diode glass doublet Model 06LAI013/076, from Melles Griot. Its focal length is 145 nun at 830
Measurement-Based Spatial Correlation and Capacity of Indoor Distributed MIMO System
Directory of Open Access Journals (Sweden)
Yan Zhang
2013-01-01
Full Text Available Distributed MIMO (D-MIMO system is one of the candidates for future wireless access networks. In this study, the spatial correlation and capacity in indoor D-MIMO system are presented. All results are from the actual channel measurements in typical indoor scenarios, including office and corridor. Based on measured data, spatial correlation coefficients between distributed transmitting antennas are analyzed. Although the literature about D-MIMO system assumes the small scale fading between distributed antennas is independent, we find that spatial correlation may still exist in specific propagation scenario. This correlation can also degrade the performance of D-MIMO system. To mitigate the impact of spatial correlation, one efficient method is to use transmitting antenna selection technique.
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.
Program system for processing of spectra obtained on the multidetector correlation device (MUK)
International Nuclear Information System (INIS)
Venos, D.; Adam, J.; Hnatowicz, V.; Honusek, M.
1988-01-01
A program system used by evaluation of multidimensional coincidence spectra is described. The spectra recorded on magnetic tapes are obtained by means of multidetector correlation device (MUK). The angular correlation coefficients A 22 and A 44 for the given cascades of gamma transitions are the final result of the calculations. The system operates in DOS/ES system of the EC-1040 computer with the 1024 Kbyte memeory. All the codes are written in fortran language
Central nervous system tumors: Radiologic pathologic correlation and diagnostic approach
Directory of Open Access Journals (Sweden)
Ishita Pant
2015-01-01
Full Text Available Objective: This study was conducted to formulate location-wise radiologic diagnostic algorithms and assess their concordance with the final histopathological diagnosis so as to evaluate their utility in a rural setting where only basic facilities are available. Materials and Methods: A retrospective analysis to assess the concordance of radiology (primarily MRI with final histopathology report was done. Based on the most common incidence of tumor location and basic radiology findings, diagnostic algorithms were prepared. Results: For supratentorial intraaxial parenchymal location concordance was seen in all high-grade astrocytomas, low- and high-grade oligodendrogliomas, metastatic tumors, primitive neuroectodermal tumors, high-grade ependymomas, neuronal and mixed neuro-glial tumors and tumors of hematopoietic system. Lowest concordance was seen in low-grade astrocytomas. In the supratentorial intraaxial ventricular location, agreement was observed in choroid plexus tumors, ependymomas, low-grade astrocytomas and meningiomas; in the supratentorial extraaxial location, except for the lack of concordance in the only case of metastatic tumor, concordance was observed in meningeal tumors, tumors of the sellar region, tumors of cranial and paraspinal nerves; the infratentorial intraaxial parenchymal location showed agreement in low- as well as high-grade astrocytomas, metastatic tumors, high-grade ependymoma, embryonal tumors and hematopoietic tumors; in the infratentorial intraaxial ventricular location, except for the lack of concordance in one case of low-grade astrocytoma and two cases of medulloblastomas, agreement was observed in low- and high-grade ependymoma; infratentorial extraaxial tumors showed complete agreement in all tumors of cranial and paraspinal nerves, meningiomas, and hematopoietic tumors. Conclusion: A location-based approach to central nervous system (CNS tumors is helpful in establishing an appropriate differential diagnosis.
Bell Correlations in a Many-Body System with Finite Statistics
Wagner, Sebastian; Schmied, Roman; Fadel, Matteo; Treutlein, Philipp; Sangouard, Nicolas; Bancal, Jean-Daniel
2017-10-01
A recent experiment reported the first violation of a Bell correlation witness in a many-body system [Science 352, 441 (2016)]. Following discussions in this Letter, we address here the question of the statistics required to witness Bell correlated states, i.e., states violating a Bell inequality, in such experiments. We start by deriving multipartite Bell inequalities involving an arbitrary number of measurement settings, two outcomes per party and one- and two-body correlators only. Based on these inequalities, we then build up improved witnesses able to detect Bell correlated states in many-body systems using two collective measurements only. These witnesses can potentially detect Bell correlations in states with an arbitrarily low amount of spin squeezing. We then establish an upper bound on the statistics needed to convincingly conclude that a measured state is Bell correlated.
Sampling Transition Pathways in Highly Correlated Complex Systems
Energy Technology Data Exchange (ETDEWEB)
Chandler, David
2004-10-20
This research grant supported my group's efforts to apply and extend the method of transition path sampling that we invented during the late 1990s. This methodology is based upon a statistical mechanics of trajectory space. Traditional statistical mechanics focuses on state space, and with it, one can use Monte Carlo methods to facilitate importance sampling of states. With our formulation of a statistical mechanics of trajectory space, we have succeeded at creating algorithms by which importance sampling can be done for dynamical processes. In particular, we are able to study rare but important events without prior knowledge of transition states or mechanisms. In perhaps the most impressive application of transition path sampling, my group combined forces with Michele Parrinello and his coworkers to unravel the dynamics of auto ionization of water [5]. This dynamics is the fundamental kinetic step of pH. Other applications concern nature of dynamics far from equilibrium [1, 7], nucleation processes [2], cluster isomerization, melting and dissociation [3, 6], and molecular motors [10]. Research groups throughout the world are adopting transition path sampling. In part this has been the result of our efforts to provide pedagogical presentations of the technique [4, 8, 9], as well as providing new procedures for interpreting trajectories of complex systems [11].
The Electron-Phonon Interaction in Strongly Correlated Systems
International Nuclear Information System (INIS)
Castellani, C.; Grilli, M.
1995-01-01
We analyze the effect of strong electron-electron repulsion on the electron-phonon interaction from a Fermi-liquid point of view and show that the electron-electron interaction is responsible for vertex corrections, which generically lead to a strong suppression of the electron-phonon coupling in the v F q/ω >>1 region, while such effect is not present when v F q/ω F is the Fermi velocity and q and ω are the transferred momentum and frequency respectively. In particular the e-ph scattering is suppressed in transport properties which are dominated by low-energy-high-momentum processes. On the other hand, analyzing the stability criterion for the compressibility, which involves the effective interactions in the dynamical limit, we show that a sizable electron-phonon interaction can push the system towards a phase-separation instability. Finally a detailed analysis of these ideas is carried out using a slave-boson approach for the infinite-U three-band Hubbard model in the presence of a coupling between the local hole density and a dispersionless optical phonon. (author)
Correlation between obesity, adipokines and the immune system
Directory of Open Access Journals (Sweden)
Marcos Regini Silveira
2009-09-01
Full Text Available Obesity is a worldwide health problem and the increase in its incidence, risks and consequences are a matter of growing concern. Obesity is characterized by the accumulation of fat in the body. Many studies are currently investigating obesity and associated comorbidities in an attempt to clarify the mechanisms involved. Fat tissue is a dynamic organ that secretes several factors, including adipokines. Adipokines are bioactive peptides secreted by fat cells, which are important for energy regulation and inflammatory and immune responses. Leptin, adiponectin and resistin are the most studied adipokines. The aim of this review was to gather information about these adipokines (leptin, adiponectin and resistin and their relationship with the immune response in obese individuals, as well as the susceptibility of these patients to infections. The results of the literature review permit some observations. The circulating levels of these adipokines are directly involved in the degree of obesity of the patient. High or low circulating concentrations of these adipokines may have beneficial or negative effects on immune competence, with obese patients being more susceptible to infection and inflammation than eutrophic individuals.Key words: Obesity; Adipokines; Leptin; Adiponectin; Resistin; Immune system.
The Alpine-Carpathian-Dinaridic orogenic system: correlation and evolution of tectonic units
Schmid, S.M.; Bernoulli, D.; Fügenschuh, B.; Matenco, L.C.; Schefer, S.; Schuster, R.; Tischler, M.; Ustaszewski, K.
2008-01-01
A correlation of tectonic units of the Alpine-Carpathian-Dinaridic system of orogens, including the substrate of the Pannonian and Transylvanian basins, is presented in the form of a map. Combined with a series of crustal-scale cross sections this correlation of tectonic units yields a clearer
Two Point Correlation Functions for a Periodic Box-Ball System
Directory of Open Access Journals (Sweden)
Jun Mada
2011-03-01
Full Text Available We investigate correlation functions in a periodic box-ball system. For the second and the third nearest neighbor correlation functions, we give explicit formulae obtained by combinatorial methods. A recursion formula for a specific N-point functions is also presented.
Tests of a robust eddy correlation system for sensible heat flux
Blanford, J. H.; Gay, L. W.
1992-03-01
Sensible heat flux estimates from a simple, one-propeller eddy correlation system (OPEC) were compared with those from a sonic anemometer eddy correlation system (SEC). In accordance with similarity theory, the performance of the OPEC system improved with increasing height of the sensor above the surface. Flux totals from the two systems at sites with adequate fetch were in excellent agreement after frequency response corrections were applied. The propeller system appears suitable for long periods of unattended measurement. The sensible heat flux measurements can be combined with net radiation and soil heat flux measurements to estimate latent heat as a residual in the surface energy balance.
Tunable two-photon correlation in a double-cavity optomechanical system
Directory of Open Access Journals (Sweden)
Zhi-Bo Feng
2015-12-01
Full Text Available Correlated photons are essential sources for quantum information processing. We propose a practical scheme to generate pairs of correlated photons in a controllable fashion from a double-cavity optomechanical system, where the variable optomechanical coupling strength makes it possible to tune the photon correlation at our will. The key operation is based on the repulsive or attractive interaction between the two photons intermediated by the mechanical resonator. The present protocol could provide a potential approach to coherent control of the photon correlation using the optomechanical cavity.
A normalisation for the four - detector system for gamma - gamma angular correlation studies
International Nuclear Information System (INIS)
Kiang, G.C.; Chen, C.H.; Niu, W.F.
1994-01-01
A normalisation method for the multiple - HPGe - detector system is described. The system consists of four coaxial HPGe detectors with a CAMAC event - by - event data acquisition system, enabling to measure six gamma -gamma coincidences of angles simultaneously. An application for gamma - gamma correlation studies of Kr 82 is presented and discussed. 3 figs., 6 refs. (author)
A CATASTROPHIC-CUM-RESTORATIVE QUEUING SYSTEM WITH CORRELATED BATCH ARRIVALS AND VARIABLE CAPACITY
Directory of Open Access Journals (Sweden)
Rakesh Kumar
2008-07-01
Full Text Available In this paper, we study a catastrophic-cum-restorative queuing system with correlated batch arrivals and service in batches of variable sizes. We perform the transient analysis of the queuing model. We obtain the Laplace Transform of the probability generating function of system size. Finally, some particular cases of the model have been derived and discussed. Keywords: Queue length, Catastrophes, Correlated batch arrivals, Broadband services, Variable service capacity, and Restoration.
Gaussian random-matrix process and universal parametric correlations in complex systems
International Nuclear Information System (INIS)
Attias, H.; Alhassid, Y.
1995-01-01
We introduce the framework of the Gaussian random-matrix process as an extension of Dyson's Gaussian ensembles and use it to discuss the statistical properties of complex quantum systems that depend on an external parameter. We classify the Gaussian processes according to the short-distance diffusive behavior of their energy levels and demonstrate that all parametric correlation functions become universal upon the appropriate scaling of the parameter. The class of differentiable Gaussian processes is identified as the relevant one for most physical systems. We reproduce the known spectral correlators and compute eigenfunction correlators in their universal form. Numerical evidence from both a chaotic model and weakly disordered model confirms our predictions
Zhao, Kexin; van der Spoel, Aarnoud; Castiglioni, Claudia; Gale, Sarah; Fujiwara, Hideji; Ory, Daniel S; Ridgway, Neale D
2018-06-01
Microdeletions in 19q12q13.12 cause a rare and complex haploinsufficiency syndrome characterized by intellectual deficiency, developmental delays, and neurological movement disorders. Variability in the size and interval of the deletions makes it difficult to attribute the complex clinical phenotype of this syndrome to an underlying gene(s). As an alternate approach, we examined the biochemical and metabolic features of fibroblasts from an affected individual to derive clues as to the molecular basis for the syndrome. Immunofluorescence and electron microscopy of affected fibroblasts revealed an abnormal endo-lysosomal compartment that was characterized by rapid accumulation of lysosomotropic dyes, elevated LAMP1 and LAMP2 expression and vacuoles containing membrane whorls, common features of lysosomal lipid storage disorders. The late endosomes-lysosomes (LE/LY) of affected fibroblasts accumulated low-density lipoprotein cholesterol, and displayed reduced cholesterol esterification and increased de novo cholesterol synthesis, indicative of defective cholesterol transport to the endoplasmic reticulum. Affected fibroblasts also had increased ceramide and sphingolipid mass, altered glycosphingolipid species and accumulation of a fluorescent lactosylceramide probe in LE/LY. Autophagosomes also accumulated in affected fibroblasts because of decreased fusion with autolysosomes, a defect associated with other lysosomal storage diseases. Attempts to correct the cholesterol/sphingolipid storage defect in fibroblasts with cyclodextrin, sphingolipid synthesis inhibitors or by altering ion transport were unsuccessful. Our data show that 19q13.12 deletion fibroblasts have abnormal accumulation of cholesterol and sphingolipids in the endo-lysosomal system that compromises organelle function and could be an underlying cause of the clinical features of the syndrome. Copyright © 2018 Elsevier B.V. All rights reserved.
Model of the Correlation between Lidar Systems and Wind Turbines for Lidar-Assisted Control
DEFF Research Database (Denmark)
Schlipf, David; Cheng, Po Wen; Mann, Jakob
2013-01-01
- or spinner-based lidar system. If on the one hand, the assumed correlation is overestimated, then the uncorrelated frequencies of the preview will cause unnecessary control action, inducing undesired loads. On the other hand, the benefits of the lidar-assisted controller will not be fully exhausted......, if correlated frequencies are filtered out. To avoid these miscalculations, this work presents a method to model the correlation between lidar systems and wind turbines using Kaimal wind spectra. The derived model accounts for different measurement configurations and spatial averaging of the lidar system......Investigations of lidar-assisted control to optimize the energy yield and to reduce loads of wind turbines have increased significantly in recent years. For this kind of control, it is crucial to know the correlation between the rotor effective wind speed and the wind preview provided by a nacelle...
High-speed holographic correlation system for video identification on the internet
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.
СREATION OF CORRELATION FUNCTIONS OF LINEAR CONTINUOUS SYSTEMS BASED ON THEIR FUNDAMENTAL MATRICES
Directory of Open Access Journals (Sweden)
N. A. Vunder
2015-11-01
Full Text Available The paper presents a method of creating correlation matrices and functions of the state vectors and outputs of the linear continuous systems functioning under the conditions of stochastic stationary, in a broad sense, effects. Fundamental matrices form the basis of the method. We have shown that for the linear continuous systems with single dimensional input and single dimensional output the correlation output function of such system can be found as the free movement of this system generated by its initial state. This state is constructed from the variance matrix of the state vector and the transposed output matrix. We have elucidated that when a continuous system belongs to a class of multi-dimensional input – multi-dimensional output systems, the following options are available for solving the problem of creation of the correlation function of a linear system. The first option is to partition the system into separate channels. Then the approach developed for systems with onedimensional input and one-dimensional output is applied to each of the separate channels. The second option is used to preserve the vector nature of the stochastic external influence. It consists in partition of output vector to scalar components by separating output matrix into separate rows with subsequent formation of the correlation function according to the scheme for single dimensional input and single dimensional output type systems. The third option is based on the scalarization of matrix correlation output function by applying the singular value decomposition to it. That gives the possibility to form scalar majorant and minorant of correlation output functions. We have established that a key component of a computational procedure of creating the correlation function of continuous linear system is a variance matrix of the system state vector. In the case of functioning under an exogenous stochastic effect like "white noise" the variance matrix is calculated by
Dane, Bari; Doshi, Ankur; Gfytopoulos, Soterios; Bhattacharji, Priya; Recht, Michael; Moore, William
2018-05-01
Radiology-pathology correlation is time-consuming and is not feasible in most clinical settings, with the notable exception of breast imaging. The purpose of this study was to determine if an automated radiology-pathology report pairing system could accurately match radiology and pathology reports, thus creating a feedback loop allowing for more frequent and timely radiology-pathology correlation. An experienced radiologist created a matching matrix of radiology and pathology reports. These matching rules were then exported to a novel comprehensive radiology-pathology module. All distinct radiology-pathology pairings at our institution from January 1, 2016 to July 1, 2016 were included (n = 8999). The appropriateness of each radiology-pathology report pairing was scored as either "correlative" or "non-correlative." Pathology reports relating to anatomy imaged in the specific imaging study were deemed correlative, whereas pathology reports describing anatomy not imaged with the particular study were denoted non-correlative. Overall, there was 88.3% correlation (accuracy) of the radiology and pathology reports (n = 8999). Subset analysis demonstrated that computed tomography (CT) abdomen/pelvis, CT head/neck/face, CT chest, musculoskeletal CT (excluding spine), mammography, magnetic resonance imaging (MRI) abdomen/pelvis, MRI brain, musculoskeletal MRI (excluding spine), breast MRI, positron emission tomography (PET), breast ultrasound, and head/neck ultrasound all demonstrated greater than 91% correlation. When further stratified by imaging modality, CT, MRI, mammography, and PET demonstrated excellent correlation (greater than 96.3%). Ultrasound and non-PET nuclear medicine studies demonstrated poorer correlation (80%). There is excellent correlation of radiology imaging reports and appropriate pathology reports when matched by organ system. Rapid, appropriate radiology-pathology report pairings provide an excellent opportunity to close feedback loop to the
Directory of Open Access Journals (Sweden)
O.V.Patsahan
2006-01-01
Full Text Available Based on the method of collective variables (CV with a reference system, the exact expression for the functional of the grand partition function of a m-component ionic model with charge and size asymmetry is found. Particular attention is paid to the n-th particle correlation functions of the reference system which is presented as a m-component system of "colour" hard spheres of the same diameter. A two-component model is considered in more detail. In this case the recurrence formulas for the correlation functions are found. A general case of a m-component inhomogeneous system of the "colour" hard spheres is also analysed.
Business cycles' correlation and systemic risk of the Japanese supplier-customer network.
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
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
Wang, X; Qiao, Y; Yang, L; Song, S; Han, Y; Tian, Y; Ding, M; Jin, H; Shao, F; Liu, A
2017-11-01
Leptin levels are increased in patients with systemic lupus erythematosus (SLE) but little is known on how this correlates with several disease characteristics including the frequency of regulatory T cells (Tregs). Here we compared serum leptin levels with frequency of circulating Tregs in 47 lupus patients vs. 25 healthy matched controls. Correlations with lupus disease activity were also analyzed, as well as Treg proliferation potential. It was found that leptin was remarkably increased in SLE patients as compared to controls, particularly in SLE patients with moderate and severe active SLE, and the increase correlated with disease activity. Importantly, increased leptin in lupus patients inversely correlated with the frequency of Tregs but not in controls, and leptin neutralization resulted in the expansion of Tregs ex vivo. Thus, hyperleptinemia in lupus patients correlates directly with disease activity and inversely with Treg frequency. The finding that leptin inhibition expands Tregs in SLE suggests possible inhibition of this molecule for an enhanced Treg function in the disease.
Ferromagnetic instabilities in disordered systems in the limit of strong correlations
International Nuclear Information System (INIS)
Magalhaes, A.N.; Troper, A.; Gomes, A.A.
1976-05-01
One derives the criterion for ferromagnetic instabilities in hybridized disordered systems, e.g. transition metal like systems and actinides, within the Coherent Potential Approximation (CPA), the electron-electron correlations being described by Hubbard' approximation. In the case of actinides, one treats approximately the motion of d electrons while the diagonal disorder within the f band is fully taken into account. In the case of a trnsition metal like system, except for Hubbard's approximation in dealing with d-d electron correlations, our procedure is exact within the spirit of CPA
The Role of screening in the strongly correlated 2D systems
Hwang, E H
2003-01-01
We investigate recently observed experiments in the strongly correlated 2D systems (r sub s >> 1) (low-density 2D plasmons, metallic behaviour of 2D systems and frictional drag resistivity between two 2D hole layers). We compare them with our theoretical results calculated within a conventional Fermi liquid theory with RPA screening.
System reliability with correlated components: Accuracy of the Equivalent Planes method
Roscoe, K.; Diermanse, F.; Vrouwenvelder, A.C.W.M.
2015-01-01
Computing system reliability when system components are correlated presents a challenge because it usually requires solving multi-fold integrals numerically, which is generally infeasible due to the computational cost. In Dutch flood defense reliability modeling, an efficient method for computing
System reliability with correlated components : Accuracy of the Equivalent Planes method
Roscoe, K.; Diermanse, F.; Vrouwenvelder, T.
2015-01-01
Computing system reliability when system components are correlated presents a challenge because it usually requires solving multi-fold integrals numerically, which is generally infeasible due to the computational cost. In Dutch flood defense reliability modeling, an efficient method for computing
Springer, P.
1993-01-01
This paper discusses the method in which the Cascade-Correlation algorithm was parallelized in such a way that it could be run using the Time Warp Operating System (TWOS). TWOS is a special purpose operating system designed to run parellel discrete event simulations with maximum efficiency on parallel or distributed computers.
Correlation Decay in Fermionic Lattice Systems with Power-Law Interactions at Nonzero Temperature
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.
Method of correlation operators in the theory of a system of particles with strong interactions
International Nuclear Information System (INIS)
Kuz'min, Y.M.
1985-01-01
A similarity transformation of the density matrix is performed with the help of the correlation operator. This does not change the value of the partition function. A method of calculating the transformed partition function with the help of a finite translation operator is given. A general system of coupled equations is obtained from which the matrix elements of correlation operators of increasing order can be found
Huang, K.-N.
1977-01-01
A computational procedure for calculating correlated wave functions is proposed for three-particle systems interacting through Coulomb forces. Calculations are carried out for the muonic helium atom. Variational wave functions which explicitly contain interparticle coordinates are presented for the ground and excited states. General Hylleraas-type trial functions are used as the basis for the correlated wave functions. Excited-state energies of the muonic helium atom computed from 1- and 35-term wave functions are listed for four states.
Energy Technology Data Exchange (ETDEWEB)
Katano, Susumu [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment
1998-03-01
Neutron scattering experiments in our group on strongly correlated electron systems are reviewed Metal-insulator transitions caused by structural phase transitions in (La{sub 1-x}Sr{sub x}) MnO{sub 3}, a novel magnetic transition in the CeP compound, correlations between antiferromagnetism and superconductivity in UPd{sub 2}Al{sub 3} and so forth are discussed. Here, in this note, the phase transition of Mn-oxides was mainly described. (author)
[Correlation analysis of G870A CCND1 gene polymorphism with digestive system tumors].
Yang, Shu-Min; Shi, Ya-Lin
2016-11-20
To study the correlation of G870A CCND1 gene polymorphism and digestive system tumors. From August 2010 to August 2014, 164 digestive system cancer patients (including 82 patients with gastric cancer and 82 with colorectal cancer) and 82 healthy subjects (control group) were examined with PCR-restriction fragment length polymorphism (PCR-RFLP). The distribution of CCND1 gene G870A frequency in the 3 groups and its association with tumor staging and grading were analyzed. The frequencies of the GG, GA and AA genotypes in G870A CCND1 gene loci in patients with gastric cancer and colorectal cancer differed significantly from those in the control group (Pdigestive system tumors (Pdigestive system cancer risk than the GG genotype (Pdigestive system tumors. The allele A is associated with an increased risk of digestive system tumors and correlated with the tumor differentiation and staging of the tumor.
Strongly correlated photons generated by coupling a three- or four-level system to a waveguide
Zheng, Huaixiu; Gauthier, Daniel J.; Baranger, Harold U.
2012-04-01
We study the generation of strongly correlated photons by coupling an atom to photonic quantum fields in a one-dimensional waveguide. Specifically, we consider a three-level or four-level system for the atom. Photon-photon bound states emerge as a manifestation of the strong photon-photon correlation mediated by the atom. Effective repulsive or attractive interaction between photons can be produced, causing either suppressed multiphoton transmission (photon blockade) or enhanced multiphoton transmission (photon-induced tunneling). As a result, nonclassical light sources can be generated on demand by sending coherent states into the proposed system. We calculate the second-order correlation function of the transmitted field and observe bunching and antibunching caused by the bound states. Furthermore, we demonstrate that the proposed system can produce photon pairs with a high degree of spectral entanglement, which have a large capacity for carrying information and are important for large-alphabet quantum communication.
Virtual-site correlation mean field approach to criticality in spin systems
International Nuclear Information System (INIS)
Sen, Aditi; Sen, Ujjwal
2013-01-01
We propose a virtual-site correlation mean field theory for dealing with interacting many-body systems. It involves a coarse-graining technique that terminates a step before the mean field theory: While mean field theory deals with only single-body physical parameters, the virtual-site correlation mean field theory deals with single- as well as two-body ones, and involves a virtual site for every interaction term in the Hamiltonian. We generalize the theory to a cluster virtual-site correlation mean field, that works with a fundamental unit of the lattice of the many-body system. We apply these methods to interacting Ising spin systems in several lattice geometries and dimensions, and show that the predictions of the onset of criticality of these models are generally much better in the proposed theories as compared to the corresponding ones in mean field theories
Energy Technology Data Exchange (ETDEWEB)
Ju, Yun Jae; Lee, Hee Joon [Kookmin Univ., Seoul (Korea, Republic of); Kang, Hanok; Lee, Taeho; Park, Cheontae [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)
2013-12-15
Recently, condensation heat exchangers have been studied for applications to the passive cooling systems of nuclear plants. To design vertical-type condensation heat exchangers in secondary passive cooling systems, TSCON (Thermal Sizing of CONdenser), a thermal sizing program for a condensation heat exchanger, was developed at KAERI (Korea Atomic Energy Research Institute). In this study, the existing condensation heat transfer correlation of TSCON was evaluated using 1,157 collected experimental data points from the heat exchanger of a secondary passive cooling system for the case of pure steam condensation. The investigation showed that the Shah correlation, published in 2009, provided the most satisfactory results for the heat transfer coefficient with a mean absolute error of 34.8%. It is suggested that the Shah correlation is appropriate for designing a condensation heat exchanger in TSCON.
Temporal cross-correlation asymmetry and departure from equilibrium in a bistable chemical system.
Bianca, C; Lemarchand, A
2014-06-14
This paper aims at determining sustained reaction fluxes in a nonlinear chemical system driven in a nonequilibrium steady state. The method relies on the computation of cross-correlation functions for the internal fluctuations of chemical species concentrations. By employing Langevin-type equations, we derive approximate analytical formulas for the cross-correlation functions associated with nonlinear dynamics. Kinetic Monte Carlo simulations of the chemical master equation are performed in order to check the validity of the Langevin equations for a bistable chemical system. The two approaches are found in excellent agreement, except for critical parameter values where the bifurcation between monostability and bistability occurs. From the theoretical point of view, the results imply that the behavior of cross-correlation functions cannot be exploited to measure sustained reaction fluxes in a specific nonlinear system without the prior knowledge of the associated chemical mechanism and the rate constants.
Genuine quantum correlations in quantum many-body systems: a review of recent progress.
De Chiara, Gabriele; Sanpera, Anna
2018-04-19
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. © 2018 IOP Publishing Ltd.
International Nuclear Information System (INIS)
Lissillour, R.; Guerillot, C.R.
1975-01-01
The self-correlated field method is based on the insertion in the group product wave function of pair functions built upon a set of correlated ''local'' functions and of ''nonlocal'' functions. This work is an application to three-electron systems. The effects of the outer electron on the inner pair are studied. The total electronic energy and some intermediary results such as pair energies, Coulomb and exchange ''correlated'' integrals, are given. The results are always better than those given by conventional SCF computations and reach the same level of accuracy as those given by more laborious methods used in correlation studies. (auth)
Fatma, Firdos; Verma, Sonam; Kamal, Aisha; Srivastava, Alka
2018-02-01
Pesticides are a group of chemical substances which are widely used to improve agricultural production. However, these substances could be persistent in soil and water, accumulative in sediment or bio-accumulative in biota depending on their solubility, leading to different types of environmental pollution. The present study was done to assess the impact of pesticides-mancozeb and chlorpyrifos, via morphological and physiological parameters using Allium cepa test system. Phytotoxic effects of pesticides were examined via germination percentage, survival percentage, root and shoot length, root shoot length ratio, seedling vigor index, percentage of phytotoxicity and tolerance index. Oxidative stress on Allium seedlings caused by pesticides was also assessed by investigating the activity of antioxidative enzymes viz. catalase, peroxidase and superoxide dismutase. Correlation was worked out between morphological parameters and antioxidative enzymes to bring out the alliance between them. Mancozeb and chlorpyrifos concentrations were significantly and positively correlated with the activity of antioxidative enzymes and negatively correlated with morphological parameters. Significant positive correlation between various morphological parameters showed their interdependency. However, negative correlation was obtained between activity of antioxidative enzymes and morphological parameters. The enzymes however, showed positive correlation with each other. Based on our result we can conclude that all morphological parameters were adversely affected by the two pesticides as reflected by phytotoxicity in Allium . Their negative correlation with activity of antioxidative enzymes indicates that upregulation of antioxidative enzymes is not sufficient to overcome the toxic effect, thereby signifying the threat being caused by the regular use of these pesticides.
Evidence of tensor correlations in the nuclear many-body system using a modern NN potential
International Nuclear Information System (INIS)
Fiase, J.O.; Nkoma, J.S.; Sharmaand, L.K.; Hosaka, A.
2003-01-01
In this paper we show evidence of the importance of tensor correlations in the nuclear many-body system by calculating the effective two-body nuclear matrix elements in the frame work of the Lowest-Order Constrained Variational (LOCV) technique with two-body correlation functions using the Reid93 potential. We have achieved this by switching on and off the strength of the tensor correlations, α k . We have found that in order to obtain reasonable agreement with earlier calculations based on the G-matrix theory, we must turn on the strength of the tensor correlations especially in the triplet even (TE) and tensor even (TNE) channels to take the value of approximately, 0.05. As an application, we have estimated the value of the Landau - Migdal parameter, g' NN which we found to be g' NN = 0.65. This compares favorably with the G-matrix calculated value of g' NN = 0.54. (author)
Enhancement and sign change of magnetic correlations in a driven quantum many-body system
Görg, Frederik; Messer, Michael; Sandholzer, Kilian; Jotzu, Gregor; Desbuquois, Rémi; Esslinger, Tilman
2018-01-01
Periodic driving can be used to control the properties of a many-body state coherently and to realize phases that are not accessible in static systems. For example, exposing materials to intense laser pulses makes it possible to induce metal-insulator transitions, to control magnetic order and to generate transient superconducting behaviour well above the static transition temperature. However, pinning down the mechanisms underlying these phenomena is often difficult because the response of a material to irradiation is governed by complex, many-body dynamics. For static systems, extensive calculations have been performed to explain phenomena such as high-temperature superconductivity. Theoretical analyses of driven many-body Hamiltonians are more challenging, but approaches have now been developed, motivated by recent observations. Here we report an experimental quantum simulation in a periodically modulated hexagonal lattice and show that antiferromagnetic correlations in a fermionic many-body system can be reduced, enhanced or even switched to ferromagnetic correlations (sign reversal). We demonstrate that the description of the many-body system using an effective Floquet-Hamiltonian with a renormalized tunnelling energy remains valid in the high-frequency regime by comparing the results to measurements in an equivalent static lattice. For near-resonant driving, the enhancement and sign reversal of correlations is explained by a microscopic model of the system in which the particle tunnelling and magnetic exchange energies can be controlled independently. In combination with the observed sufficiently long lifetimes of the correlations in this system, periodic driving thus provides an alternative way of investigating unconventional pairing in strongly correlated systems experimentally.
International Nuclear Information System (INIS)
Xue, Liyuan; Yu, Yanxia; Cai, Xiaoya; Pan, Hui; Wang, Zisheng
2016-01-01
Highlights: • We find that the Pancharatnam phases include the information of quantum correlations. • We show that the sudden died and alive phenomena of quantum entanglement is original in the transition of Pancharatnam phase. • We find that the faster the Pancharatnam phases change, the slower the quantum correlations decay. • We find that a subspace of quantum entanglement can exist in the Y-state. • Our results provide a useful approach experimentally to implement the time-dependent geometric quantum computation. - Abstract: We investigate time-dependent Pancharatnam phases and the relations between such geometric phases and quantum correlations, i.e., quantum discord and concurrence, of superconducting two-qubit coupling system in dissipative environment with the mixture effects of four different eigenstates of density matrix. We find that the time-dependent Pancharatnam phases not only keep the motion memory of such a two-qubit system, but also include the information of quantum correlations. We show that the sudden died and alive phenomena of quantum entanglement are intrinsic in the transition of Pancharatnam phase in the X-state and the complex oscillations of Pancharatnam phase in the Y-state. The faster the Pancharatnam phases change, the slower the quantum correlations decay. In particular, we find that a subspace of quantum entanglement can exist in the Y-state by choosing suitable coupling parameters between two-qubit system and its environment, or initial conditions.
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.
Quantum correlations of coupled superconducting two-qubit system in various cavity environments
International Nuclear Information System (INIS)
Yu, Yanxia; Fu, Guolan; Guo, L.P.; Pan, Hui; Wang, Z.S.
2013-01-01
Highlights: •We investigate dynamic evolutions of quantum and classical correlations for coupled superconducting system with various cavity environments. •We show that the quantum discord continues to reflect quantum information. •A transition of quantum discord is founded between classical loss and quantum increasing of correlations for a purely dephasing mode. •We show that the environment-dependent models can delay the loss of quantum discord. •We find that the results depend strongly on the initial angle. -- Abstract: Dynamic evolutions of quantum discord, concurrence, and classical correlation are investigated in coupled superconducting system with various cavity environments, focusing on the two-qubit system at an initially entangling X-state and Y-state. We find that for a smaller photon number, the quantum discord, concurrence and classical correlation show damped oscillations for all different decay modes. Differently from the sudden death or the dark and bright periods emerging in evolving processing of the concurrence and classical correlation, however, the quantum discord decreases gradually to zero. The results reveal that the quantum entanglement and classical correlation are lost, but the quantum discord continues to reflect quantum information in the same evolving period. For a larger photon number, the oscillations disappear. It is surprised that there exists a transition of quantum discord between classical loss and quantum increasing of correlations for a purely dephasing mode. For a larger photon number in the Y-state, the transition disappears. Moreover, we show that the environment-dependent models can delay the loss of quantum discord. The results depend strongly on the initial angle, which provide a clue to control the quantum gate of superconducting circuit
Memory Effects and Nonequilibrium Correlations in the Dynamics of Open Quantum Systems
Morozov, V. G.
2018-01-01
We propose a systematic approach to the dynamics of open quantum systems in the framework of Zubarev's nonequilibrium statistical operator method. The approach is based on the relation between ensemble means of the Hubbard operators and the matrix elements of the reduced statistical operator of an open quantum system. This key relation allows deriving master equations for open systems following a scheme conceptually identical to the scheme used to derive kinetic equations for distribution functions. The advantage of the proposed formalism is that some relevant dynamical correlations between an open system and its environment can be taken into account. To illustrate the method, we derive a non-Markovian master equation containing the contribution of nonequilibrium correlations associated with energy conservation.
Inner-shell correlations and Sturm expansions in coupled perturbation calculations of atomic systems
International Nuclear Information System (INIS)
Sherstyuk, A.I.; Solov'eva, G.S.
1995-01-01
It is shown that virtual Hartree-Fock orbitals in Sturm-type expansions can be used to calculate the response of atomic systems to an external field within the framework of the coupled perturbation theory with allowance for correlation effects. The corrected electron-electron interaction in a system with field-distorted orbitals is considered by adding a nonlocal potential to a one-electron Hartree-Fock operator within each group of equivalent elections. The remaining correlation effects are calculated by solving a system of equations for corrections to the radial functions. The system is solved iteratively, with each subsequent iteration corresponding to a correction of an increasingly higher order in the electron--electron interaction. The explicit expression derived for the polarizability contains one-and two-particle radial integrals of the Sturm functions
Resonant soft x-ray scattering and charge density waves in correlated systems
Rusydi, Andrivo
2006-01-01
Summary This work describes results obtained on the study of charge density waves (CDW) in strongly correlated systems with a new experimental method: resonant soft x-ray scattering (RSXS). The basic motivation is the 1986 discovery by Bednorz and Müler of a new type of superconductor, based on Cu
Quantum group random walks in strongly correlated 2+1 D spin systems
International Nuclear Information System (INIS)
Protogenov, A.P.; Rostovtsev, Yu.V.; Verbus, V.A.
1994-06-01
We consider the temporal evolution of strong correlated degrees of freedom in 2+1 D spin systems using the Wilson operator eigenvalues as variables. It is shown that the quantum-group diffusion equation at deformation parameter q being the k-th root of unity has the polynomial solution of degree k. (author). 20 refs, 1 tab
Eigenvalue distributions of correlated multichannel transfer matrices in strongly scattering systems
Sprik, R.; Tourin, A.; de Rosny, J.; Fink, M.
2008-01-01
We experimentally study the effects of correlations in the propagation of ultrasonic waves in water from a multielement source to a multielement detector through a strongly scattering system of randomly placed vertical rods. Due to the strong scattering, the wave transport in the sample is in the
Correlation between observable of four nucleon system in two-body model
International Nuclear Information System (INIS)
Barlette, V.E.
1988-01-01
The four nucleon system with effective nucleon-trinucleon interaction for s waves in states of spin Y = 0 and isospin Y = 0, is studied. The correlations between four nucleon systemn and scattering wavelength, binding energies and, coulomb energy of four nucleons are investigated by N/D method considering only the excited state. (M.C.K.)
Camilo, Ana E. F.; Grégio, André; Santos, Rafael D. C.
2016-05-01
Malware detection may be accomplished through the analysis of their infection behavior. To do so, dynamic analysis systems run malware samples and extract their operating system activities and network traffic. This traffic may represent malware accessing external systems, either to steal sensitive data from victims or to fetch other malicious artifacts (configuration files, additional modules, commands). In this work, we propose the use of visualization as a tool to identify compromised systems based on correlating malware communications in the form of graphs and finding isomorphisms between them. We produced graphs from over 6 thousand distinct network traffic files captured during malware execution and analyzed the existing relationships among malware samples and IP addresses.
Development of OCDMA system based on Flexible Cross Correlation (FCC) code with OFDM modulation
Aldhaibani, A. O.; Aljunid, S. A.; Anuar, M. S.; Arief, A. R.; Rashidi, C. B. M.
2015-03-01
The performance of the OCDMA systems is governed by numerous quantitative parameters such as the data rate, simultaneous number of users, the powers of transmitter and receiver, and the type of codes. This paper analyzes the performance of the OCDMA system using OFDM technique to enhance the channel data rate, to save power and increase the number of user of OSCDMA systems compared with previous hybrid subcarrier multiplexing/optical spectrum code division multiplexing (SCM/OSCDM) system. The average received signal to noise ratio (SNR) with the nonlinearity of subcarriers is derived. The theoretical results have been evaluated based on BER and number of users as well as amount of power saved. The proposed system gave better performance and save around -6 dBm of the power as well as increase the number of users twice compare to SCM/OCDMA system. In addition it is robust against interference and much more spectrally efficient than SCM/OCDMA system. The system was designed based on Flexible Cross Correlation (FCC) code which is easier construction, less complexity of encoder/decoder design and flexible in-phase cross-correlation for uncomplicated to implement using Fiber Bragg Gratings (FBGs) for the OCDMA systems for any number of users and weights. The OCDMA-FCC_OFDM improves the number of users (cardinality) 108% compare to SCM/ODCMA-FCC system.
Fundamental Data Standards for Science Data System Interoperability and Data Correlation
Hughes, J. Steven; Gopala Krishna, Barla; Rye, Elizabeth; Crichton, Daniel
The advent of the Web and languages such as XML have brought an explosion of online science data repositories and the promises of correlated data and interoperable systems. However there have been relatively few successes in meeting the expectations of science users in the internet age. For example a Google-like search for images of Mars will return many highly-derived and appropriately tagged images but largely ignore the majority of images in most online image repositories. Once retrieved, users are further frustrated by poor data descriptions, arcane formats, and badly organized ancillary information. A wealth of research indicates that shared information models are needed to enable system interoperability and data correlation. However, at a more fundamental level, data correlation and system interoperability are dependant on a relatively few shared data standards. A com-mon data dictionary standard, for example, allows the controlled vocabulary used in a science repository to be shared with potential collaborators. Common data registry and product iden-tification standards enable systems to efficiently find, locate, and retrieve data products and their metadata from remote repositories. Information content standards define categories of descriptive data that help make the data products scientifically useful to users who were not part of the original team that produced the data. The Planetary Data System (PDS) has a plan to move the PDS to a fully online, federated system. This plan addresses new demands on the system including increasing data volume, numbers of missions, and complexity of missions. A key component of this plan is the upgrade of the PDS Data Standards. The adoption of the core PDS data standards by the International Planetary Data Alliance (IPDA) adds the element of international cooperation to the plan. This presentation will provide an overview of the fundamental data standards being adopted by the PDS that transcend science domains and that
Towards an Autonomous System Monitor for Mitigating Correlation Attacks in the Tor Network
Hoang, Nguyen Phong
2016-01-01
After carefully considering the scalability problem in Tor and exhaustively evaluating related works on AS-level adversaries, the author proposes ASmoniTor, which is an autonomous system monitor for mitigating correlation attacks in the Tor network. In contrast to prior works, which often released offline packets, including the source code of a modified Tor client and a snapshot of the Internet topology, ASmoniTor is an online system that assists end users with mitigating the threat of AS-lev...
Energy Technology Data Exchange (ETDEWEB)
Resnick, D; Pineda, C; Trudell, D
1985-01-01
A patient with systemic lupus erythematosus required an amputation of the foot related to the presence of vascular disease and infection. Radiographs obtained prior to amputation revealed osteonecrosis in virtually every bone of the foot. Radiographic-pathologic correlation documented this widespread osseous involvement. Although ischemic necrosis of bone is a well-known feature of systemic lupus erythematosus, its localization in the small bones of the foot is rare.
International Nuclear Information System (INIS)
Resnick, D.; Pineda, C.; Trudell, D.; California Univ., San Diego, La Jolla
1985-01-01
A patient with systemic lupus erythematosus required an amputation of the foot related to the presence of vascular disease and infection. Radiographs obtained prior to amputation revealed osteonecrosis in virtually every bone of the foot. Radiographic-pathologic correlation documented this widespread osseous involvement. Although ischemic necrosis of bone is a well-known feature of systemic lupus erythematosus, its localization in the small bones of the foot is rare. (orig.)
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.
Correlation as a Determinant of Configurational Entropy in Supramolecular and Protein Systems
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
Nonlocality in many-body quantum systems detected with two-body correlators
Energy Technology Data Exchange (ETDEWEB)
Tura, J., E-mail: jordi.tura@icfo.es [ICFO—Institut de Ciencies Fotoniques, Mediterranean Technology Park, 08860 Castelldefels (Barcelona) (Spain); Augusiak, R.; Sainz, A.B. [ICFO—Institut de Ciencies Fotoniques, Mediterranean Technology Park, 08860 Castelldefels (Barcelona) (Spain); Lücke, B.; Klempt, C. [Institut für Quantenoptik, Leibniz Universität Hannover, Welfengarten 1, D-30167 Hannover (Germany); Lewenstein, M.; Acín, A. [ICFO—Institut de Ciencies Fotoniques, Mediterranean Technology Park, 08860 Castelldefels (Barcelona) (Spain); ICREA—Institució Catalana de Recerca i Estudis Avançats, Lluis Campanys 3, 08010 Barcelona (Spain)
2015-11-15
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, 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.
Directory of Open Access Journals (Sweden)
Valim V.
2004-01-01
Full Text Available 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.
Directory of Open Access Journals (Sweden)
V. Valim
2004-09-01
Full Text Available 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.
International Nuclear Information System (INIS)
Mestel, B D; Osbaldestin, A H
2004-01-01
Generalizing from the case of golden mean frequency to a wider class of quadratic irrationals, we extend our renormalization analysis of the self-similarity of correlation functions in a quasiperiodically forced two-level system. We give a description of all piecewise-constant periodic orbits of an additive functional recurrence generalizing that present in the golden mean case. We establish a criterion for periodic orbits to be globally bounded, and also calculate the asymptotic height of the main peaks in the correlation function
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 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.
Improved decryption quality and security of a joint transform correlator-based encryption system
International Nuclear Information System (INIS)
Vilardy, Juan M; Millán, María S; Pérez-Cabré, Elisabet
2013-01-01
Some image encryption systems based on modified double random phase encoding and joint transform correlator architecture produce low quality decrypted images and are vulnerable to a variety of attacks. In this work, we analyse the algorithm of some reported methods that optically implement the double random phase encryption in a joint transform correlator. We show that it is possible to significantly improve the quality of the decrypted image by introducing a simple nonlinear operation in the encrypted function that contains the joint power spectrum. This nonlinearity also makes the system more resistant to chosen-plaintext attacks. We additionally explore the system resistance against this type of attack when a variety of probability density functions are used to generate the two random phase masks of the encryption–decryption process. Numerical results are presented and discussed. (paper)
Improved decryption quality and security of a joint transform correlator-based encryption system
Vilardy, Juan M.; Millán, María S.; Pérez-Cabré, Elisabet
2013-02-01
Some image encryption systems based on modified double random phase encoding and joint transform correlator architecture produce low quality decrypted images and are vulnerable to a variety of attacks. In this work, we analyse the algorithm of some reported methods that optically implement the double random phase encryption in a joint transform correlator. We show that it is possible to significantly improve the quality of the decrypted image by introducing a simple nonlinear operation in the encrypted function that contains the joint power spectrum. This nonlinearity also makes the system more resistant to chosen-plaintext attacks. We additionally explore the system resistance against this type of attack when a variety of probability density functions are used to generate the two random phase masks of the encryption-decryption process. Numerical results are presented and discussed.
Exact exchange-correlation potentials of singlet two-electron systems
Ryabinkin, Ilya G.; Ospadov, Egor; Staroverov, Viktor N.
2017-10-01
We suggest a non-iterative analytic method for constructing the exchange-correlation potential, v XC ( r ) , of any singlet ground-state two-electron system. The method is based on a convenient formula for v XC ( r ) in terms of quantities determined only by the system's electronic wave function, exact or approximate, and is essentially different from the Kohn-Sham inversion technique. When applied to Gaussian-basis-set wave functions, the method yields finite-basis-set approximations to the corresponding basis-set-limit v XC ( r ) , whereas the Kohn-Sham inversion produces physically inappropriate (oscillatory and divergent) potentials. The effectiveness of the procedure is demonstrated by computing accurate exchange-correlation potentials of several two-electron systems (helium isoelectronic series, H2, H3 + ) using common ab initio methods and Gaussian basis sets.
2012 CORRELATED ELECTRON SYSTEMS GRC AND GRS, JUNE 23-29, 2012
Energy Technology Data Exchange (ETDEWEB)
Kivelson, Steven
2012-06-29
The 2012 Gordon Conference on Correlated Electron Systems will present cutting-edge research on emergent properties arising from strong electronic correlations. While we expect the discussion at the meeting to be wide-ranging, given the breadth of the title subject matter, we have chosen several topics to be the particular focus of the talks. These are New Developments in Single and Bilayer Graphene, Topological States of Matter, including Topological Insulators and Spin Liquids, the Interplay Between Magnetism and Unconventional Superconductivity, and Quantum Critical Phenomena in Metallic Systems. We also plan to have shorter sessions on Systems Far From Equilibrium, Low Dimensional Electron Fluids, and New Directions (which will primarily focus on new experimental methodologies and their interpretation).
Research and Design on Trigger System Based on Acoustic Delay Correlation Filtering
Directory of Open Access Journals (Sweden)
Zhiyong Lei
2014-01-01
Full Text Available In the exterior trajectory test, there usually needs a muzzle or a gun muzzle trigger system to be used as start signal for other measuring device, the customary trigger systems include off- target, infrared and acoustic detection system. But inherent echo reflection of the acoustic detection system makes the original signal of sound trigger submerged in various echo interference for bursts and shooting in a closed room, so that it can’t produce accurate trigger. In order to solve this defect, this paper analyzed the mathematical model based on acoustic delay correlation filtering in detail, then put forward the constraint condition with minimum path for delay correlation filtering. In this constraint condition, delay correlation filtering can do de-noising operation accurately. In order to verify accuracy and actual performance of the model, a MEMS sound sensor was used to implement mathematical model onto project, experimental results show that this system can filter out the every path sound bounce echoes of muzzle shock wave signal and produce the desired trigger signal accurately.
Light-Cone and Diffusive Propagation of Correlations in a Many-Body Dissipative System.
Bernier, Jean-Sébastien; Tan, Ryan; Bonnes, Lars; Guo, Chu; Poletti, Dario; Kollath, Corinna
2018-01-12
We analyze the propagation of correlations after a sudden interaction change in a strongly interacting quantum system in contact with an environment. In particular, we consider an interaction quench in the Bose-Hubbard model, deep within the Mott-insulating phase, under the effect of dephasing. We observe that dissipation effectively speeds up the propagation of single-particle correlations while reducing their coherence. In contrast, for two-point density correlations, the initial ballistic propagation regime gives way to diffusion at intermediate times. Numerical simulations, based on a time-dependent matrix product state algorithm, are supplemented by a quantitatively accurate fermionic quasiparticle approach providing an intuitive description of the initial dynamics in terms of holon and doublon excitations.
Capacity of fully correlated MIMO system using character expansion of groups
Directory of Open Access Journals (Sweden)
Ejaz Khan
2005-09-01
Full Text Available It is well known that the use of antenna arrays at both sides of communication link can result in high channel capacities provided that the propagation medium is rich scattering. In most previous works presented on MIMO wireless structures, Rayleigh fading conditions were considered. In this work, the capacity of MIMO systems under fully correlated (i.e., correlations between rows and columns of channel matrix fading is considered. We use replica method and character expansions to calculate the capacity of correlated MIMO channel in closed form. In our calculations, it is assumed that the receiver has perfect channel state information (CSI but no such information is available at the transmitter.
Zhou, Heng; Qiu, Kun; Wang, Leyang
2011-03-28
A novel wavelength-correlating receiver for incoherent Optical Code Division Multiple Access (OCDMA) system is proposed and demonstrated in this paper. Enabled by the wavelength conversion based scheme, the proposed receiver can support various code types including one-dimensional optical codes and time-spreading/wavelength-hopping two dimensional codes. Also, a synchronous detection scheme with time-to- wavelength based code acquisition is proposed, by which code acquisition time can be substantially reduced. Moreover, a novel data-validation methodology based on all-optical pulse-width monitoring is introduced for the wavelength-correlating receiver. Experimental demonstration of the new proposed receiver is presented and low bit error rate data-receiving is achieved without optical hard limiting and electronic power thresholding. For the first time, a detailed theoretical performance analysis specialized for the wavelength-correlating receiver is presented. Numerical results show that the overall performance of the proposed receiver prevails over conventional OCDMA receivers.
Nonlinear Analysis on Cross-Correlation of Financial Time Series by Continuum Percolation System
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.
Reliability Assessment of IGBT Modules Modeled as Systems with Correlated Components
DEFF Research Database (Denmark)
Kostandyan, Erik; Sørensen, John Dalsgaard
2013-01-01
configuration. The estimated system reliability by the proposed method is a conservative estimate. Application of the suggested method could be extended for reliability estimation of systems composing of welding joints, bolts, bearings, etc. The reliability model incorporates the correlation between...... was applied for the systems failure functions estimation. It is desired to compare the results with the true system failure function, which is possible to estimate using simulation techniques. Theoretical model development should be applied for the further research. One of the directions for it might...... be modeling the system based on the Sequential Order Statistics, by considering the failure of the minimum (weakest component) at each loading level. The proposed idea to represent the system by the independent components could also be used for modeling reliability by Sequential Order Statistics....
Correlation Assessment of Tax System Risk and Profitability in the Russian Regions
Directory of Open Access Journals (Sweden)
Marina Yuryevna Malkina
2015-09-01
Full Text Available The subject of the article is the risk, returnm and efficiency of the tax systems in the regions of the Russian Federation. Research methods: deflating GRP and tax revenues at regional level; calculating the standard deviations; G. Markowitz portfolio approach; W. Sharpe ratio calculating; correlation and regression analysis. Results obtained: 1 comparative risk profile of various taxes and their groups in the Russian Federation; 2 clustering the Russian regions in terms of risk and return of tax systems; 3 regression between the risk of regional tax systems, relative scale of regional economics and tax return based on panel data of the Russian regions in 2006-2012; 4 ranking of the RF regions on the effectiveness of their tax systems, estimated by W. Sharpe ratio. In the paper, the authors have concluded: 1 all taxes (tax group collected in the Russian regions demonstrate a positive statistical relationship between return and risk, but with different correlation; 2 the risk of regional tax system depends on the structure of tax revenues in given region, the risks of collected taxes and the covariance of different taxes revenues to each other, and joint effect of these factors is estimated by means of portfolio approach by G. Markowitz; 3 the correlation between return and risk of the tax systems of the subjects of Russian Federation considering the scale of regional economics accounts for 75 %; 4 the risk of the Russian tax system is significantly provided by 19 major high-risk regions with more than 65 share in the total state tax revenues; 5 the effectiveness of regional tax systems estimated by the Sharpe ratio depends on both the objective and subjective factors affecting the yield and volatility of tax revenues in a region. Obtained results can be used by researchers in further dynamic and comparative analysis of regional tax systems’ risk and return, as well as in identifying the reserves for increasing the regional tax policy
Directory of Open Access Journals (Sweden)
Rajesh Karki
2013-02-01
Full Text Available Adverse environmental impacts of carbon emissions are causing increasing concerns to the general public throughout the world. Electric energy generation from conventional energy sources is considered to be a major contributor to these harmful emissions. High emphasis is therefore being given to green alternatives of energy, such as wind and solar. Wind energy is being perceived as a promising alternative. This source of energy technology and its applications have undergone significant research and development over the past decade. As a result, many modern power systems include a significant portion of power generation from wind energy sources. The impact of wind generation on the overall system performance increases substantially as wind penetration in power systems continues to increase to relatively high levels. It becomes increasingly important to accurately model the wind behavior, the interaction with other wind sources and conventional sources, and incorporate the characteristics of the energy demand in order to carry out a realistic evaluation of system reliability. Power systems with high wind penetrations are often connected to multiple wind farms at different geographic locations. Wind speed correlations between the different wind farms largely affect the total wind power generation characteristics of such systems, and therefore should be an important parameter in the wind modeling process. This paper evaluates the effect of the correlation between multiple wind farms on the adequacy indices of wind-integrated systems. The paper also proposes a simple and appropriate probabilistic analytical model that incorporates wind correlations, and can be used for adequacy evaluation of multiple wind-integrated systems.
International Nuclear Information System (INIS)
Jankowski, K.; Smentek-Mielczarek, L.
1981-01-01
Results of model studies of the impact of electron correlation on the forced electric dipole transition probabilities between states of the 4fsup(N) configuration are reported for the [ 3 P] 0 - [ 3 F] 4 , [ 3 H] 4 transitions in Pr 3+ : LaCl 3 and for [ 7 F] 0 - [ 5 D] 2 , [ 7 F] 1 - [ 5 D] 1 hypersensitive transitions in Eu 3+ : LaCl 3 . For the former system the correlation effects cause a modification of earlier results by 40-95 per cent, whereas for the latter the probability changes by as much as two orders of magnitude. The great changes found in the case of hypersensitive transitions suggest that electron correlation effects may belong to the most important factors determining the nature of these transitions. Several types of effective correlation operators are considered and their relative importance is discussed. The results indicate that intermediate configurations including g orbitals are very important for the description of correlation effects. (author)
Uncertainty analysis of reactor safety systems with statistically correlated failure data
International Nuclear Information System (INIS)
Dezfuli, H.; Modarres, M.
1985-01-01
The probability of occurrence of the top event of a fault tree is estimated from failure probability of components that constitute the fault tree. Component failure probabilities are subject to statistical uncertainties. In addition, there are cases where the failure data are statistically correlated. Most fault tree evaluations have so far been based on uncorrelated component failure data. The subject of this paper is the description of a method of assessing the probability intervals for the top event failure probability of fault trees when component failure data are statistically correlated. To estimate the mean and variance of the top event, a second-order system moment method is presented through Taylor series expansion, which provides an alternative to the normally used Monte-Carlo method. For cases where component failure probabilities are statistically correlated, the Taylor expansion terms are treated properly. A moment matching technique is used to obtain the probability distribution function of the top event through fitting a Johnson Ssub(B) distribution. The computer program (CORRELATE) was developed to perform the calculations necessary for the implementation of the method developed. The CORRELATE code is very efficient and consumes minimal computer time. This is primarily because it does not employ the time-consuming Monte-Carlo method. (author)
Pion correlations in relativistic heavy ion collisions at Heavy Ion Spectrometer Systems (HISS)
International Nuclear Information System (INIS)
Christie, W.B. Jr.
1990-05-01
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 is 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
Momentum distributions for two-electron systems: electron correlation and the Coulomb hole
International Nuclear Information System (INIS)
Banyard, K.E.; Reed, C.E.
1978-01-01
By evaluating the distribution function f(p 12 ), where p 12 ) in momentum space can be investigated. difference[p 1 - p 2 ] the concept of a Coulomb hole Δf(p 12 ) in momentum space can be investigated. Results are presented for the isoelectronic systems H - , He and Li + . The electron correlation within each CI wavefunction was analysed into its radial and angular components so that the structure and composition of Δf(p 12 ) could be assessed. The two-particle momentum radial density distribution and several two-particle expectation quantities are also examined. The present findings indicate, that in momentum space, the radial components of correlation produce effects characteristic of total correlation in position space whereas, by contrast, angular correlation creates an opposite effect. Thus the shape and formation of Δf(p 12 ) proves to be considerably more complex than that found for its counterpart in position space. The results also reveal a noticeable change in the relative importance of the components of correlation as the momentum increases. (author)
Two- and Multi-particle Azimuthal Correlations in Small Collision Systems with the ATLAS Detector
Trzupek, Adam; The ATLAS collaboration
2017-01-01
ATLAS measurements of two-particle correlations in $\\Delta\\phi$ and $\\Delta\\eta$ are presented for $pp$ collisions at 2.76, 5.02 and 13~TeV, and for $p$+Pb collisions at 5.02 TeV. A template fitting procedure is used to subtract the dijet contribution and to extract the genuine long-range ridge correlations. This template procedure was previously used for 2.76 TeV and 13 TeV pp collisions, but is now extended to pp and $p$+Pb collisions at 5.02 TeV. In all collision systems, the ridge correlations are shown to be present even in events with a low multiplicity of produced particles, implying that the long-range correlations are not unique to rare high-multiplicity events. The properties of the correlation are shown to exhibit only a weak energy dependence and are remarkably similar to that observed in $p$+Pb collisions. Another new aspect of this talk is a detailed study of ridge properties in collisions containing hard processes, characterized by large four-momentum transfer. This may help answering the quest...
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.
SPATIAL CORRELATION BETWEEN PHYSICAL PROPERTIES OF SOIL AND WEEDS IN TWO MANAGEMENT SYSTEMS
Directory of Open Access Journals (Sweden)
Valter Roberto Schaffrath
2015-02-01
Full Text Available The spatial correlation between soil properties and weeds is relevant in agronomic and environmental terms. The analysis of this correlation is crucial for the interpretation of its meaning, for influencing factors such as dispersal mechanisms, seed production and survival, and the range of influence of soil management techniques. This study aimed to evaluate the spatial correlation between the physical properties of soil and weeds in no-tillage (NT and conventional tillage (CT systems. The following physical properties of soil and weeds were analyzed: soil bulk density, macroporosity, microporosity, total porosity, aeration capacity of soil matrix, soil water content at field capacity, weed shoot biomass, weed density, Commelina benghalensis density, and Bidens pilosa density. Generally, the ranges of the spatial correlations were higher in NT than in CT. The cross-variograms showed that many variables have a structure of combined spatial variation and can therefore be mapped from one another by co-kriging. This combined variation also allows inferences about the physical and biological meanings of the study variables. Results also showed that soil management systems influence the spatial dependence structure significantly.
A Tephra Database With an Intelligent Correlation System, Mono-Inyo Volcanic Chain, CA
Bursik, M.; Rogova, G.
2004-12-01
We are assembling a web-accessible, relational database of information on past eruptions of the Mono-Inyo volcanic chain, eastern California. The PostgreSQL database structure follows the North American Data Model and CordLink. The database allows us to extract the features diagnostic of particular pyroclastic layers, as well as lava domes and flows. The features include depth in the section, layer thickness and internal stratigraphy, mineral assemblage, major and trace element composition, tephra componentry and granulometry, and radiocarbon age. Our working hypotheses are that 1) the database will prove useful for unraveling the complex recent volcanic history of the Mono-Inyo chain 2) aided by the use of an intelligent correlation system integrated into the database system. The Mono-Inyo chain consists of domes, craters and flows that stretch for 50 km north-south, subparallel to the Sierran range front fault system. Almost all eruptions within the chain probably occurred less than 50,000 years ago. Because of the variety of magma and eruption types, and the migration of source regions in time and space, it is nontrivial to discern patterns of behaviour. We have explored the use of multiple artificial neural networks combined within the framework of the Dempster-Shafer theory of evidence to construct a hybrid information processing system as an aid in the correlation of Mono-Inyo pyroclastic layers. It is hoped that such a system could provide information useful to discerning eruptive patterns that would otherwise be difficult to sort and categorize. In a test case on tephra layers at known sites, the intelligent correlation system was able to categorize observations correctly 96% of the time. In a test case with layers at one unknown site, and using a pairwise comparison of the unknown site with the known sites, a one-to-one correlation between the unknown site and the known sites was found to sometimes be poor. Such a result could be used to aid a
Giger, Maryellen L.; Chen, Chin-Tu; Armato, Samuel; Doi, Kunio
1999-10-26
A method and system for the computerized registration of radionuclide images with radiographic images, including generating image data from radiographic and radionuclide images of the thorax. Techniques include contouring the lung regions in each type of chest image, scaling and registration of the contours based on location of lung apices, and superimposition after appropriate shifting of the images. Specific applications are given for the automated registration of radionuclide lungs scans with chest radiographs. The method in the example given yields a system that spatially registers and correlates digitized chest radiographs with V/Q scans in order to correlate V/Q functional information with the greater structural detail of chest radiographs. Final output could be the computer-determined contours from each type of image superimposed on any of the original images, or superimposition of the radionuclide image data, which contains high activity, onto the radiographic chest image.
Correlation functions of Sp(2n) invariant higher-spin systems
Energy Technology Data Exchange (ETDEWEB)
Skvortsov, Evgeny [Arnold Sommerfeld Center for Theoretical Physics, Ludwig-Maximilians University Munich,Theresienstr. 37, D-80333 Munich (Germany); ebedev Institute of Physics,Leninsky ave 53, 119991, Moscow (Russian Federation); Sorokin, Dmitri [INFN - Sezione di Padova,via F. Marzolo 8, 35131 Padova (Italy); Tsulaia, Mirian [School of Physics M013, The University of Western Australia,35 Stirling Highway, Crawley, Perth, WA 6009 (Australia)
2016-07-26
We study the general structure of correlation functions in an Sp(2n)-invariant formulation of systems of an infinite number of higher-spin fields. For n=4,8 and 16 these systems comprise the conformal higher-spin fields in space-time dimensions D=4,6 and 10, respectively, while when n=2, one deals with conventional D=3 conformal field theories of scalars and spinors. We show that for n>2 the Sp(2n) symmetry and current conservation makes the 3-point correlators of two (rank-one or rank-two) conserved currents with a scalar operator be that of free theory. This situation is analogous to the one in conventional conformal field theories, where conservation of higher-spin currents implies that the theories are free.
Study of temporal quantum correlations in decohering B and K meson systems
Naikoo, Javid; Alok, Ashutosh Kumar; Banerjee, Subhashish
2018-03-01
In this work we study temporal quantum correlations, quantified by Leggett-Garg (LG) and LG-type inequalities, in the B and K meson systems. We use the tools of open quantum systems to incorporate the effect of decoherence which is quantified by a single phenomenological parameter. The effect of C P violation is also included in our analysis. We find that the LG inequality is violated for both B and K meson systems, the violation being most prominent in the case of K mesons and least for Bs system. Since the systems with no coherence do not violate LGI, incorporating decoherence is expected to decrease the extent of violation of LGI and is clearly brought out in our results. We show that the expression for the LG functions depends upon an additional term, apart from the experimentally measurable meson transition probabilities. This term vanishes in the limit of zero decoherence. On the other hand, the LG-type parameter can be directly expressed in terms of transition probabilities, making it a more appropriate observable for studying temporal quantum correlations in neutral meson systems.
International Nuclear Information System (INIS)
Riaz, M.O.; Ahmed, T.A.
2016-01-01
Objective: To study the correlation of anti C1q antibodies with disease activity in patients with systemic lupus erythematosus (SLE). Study Design: Cross sectional, observational study. Place and Duration of study: The Department of Immunology, Armed Forces Institute of Pathology, Rawalpindi in collaboration with Military Hospital, Rawalpindi, Pakistan Institute of Medical Sciences, Islamabad and Benazir Bhutto Hospital, Rawalpindi, from Jan 2012 to Dec 2013. Material and Methods: Patients with a clinical diagnosis of SLE were included in the study on fulfilling revised American College of Rheumatology (ACR) criteria (1997). Main outcome measures were SLE disease activity index (SLEDAI) score and anti C1q antibody levels in serum. SLEDAI scores were calculated for each patient on the basis of physical examination, patient interviews and previous clinical records. Anti C1q antibody levels in the serum were determined by enzyme-linked immunosorbent assay (ELISA) and correlated with the SLEDAI scores by calculating Pearson's correlation coefficient 'r'. The cutoff value for anti C1q antibody positivity in the serum was determined by evaluating the serum levels of anti C1q antibodies in 25 healthy subjects and was 12 U/ml. Results: Six male and forty nine female SLE patients with an age range of 16-47 years (mean 34.5 years) and 8-70 years (mean 31.7 years) respectively were studied. The correlation between anti C1q levels and SLEDAI scores in all patients was demonstrated by calculating the correlation coefficient and was not significant (r=0.19, p=0.14). However, there was an inverse correlation between anti C1q levels and SLEDAI scores in patients with severe disease and this was statistically significant (r=-0.448, p=0.037). The difference in anti C1q antibody positivity between patients with and without nephritis was not significant. The anti C1q antibody levels correlated poorly with anti double stranded deoxyribonucleic acid (dsDNA) antibody positivity. A
To the theory of spin-charge separation in one-dimensional correlated electron systems
International Nuclear Information System (INIS)
Zvyagin, A.A.
2004-01-01
Spin-charge separation is considered to be one of the key properties that distinguish low-dimensional electron systems from others. Three-dimensional correlated electron systems are described by the Fermi liquid theory. There, low-energy excitations (quasiparticles) are reminiscent of noninteracting electrons: They carry charges -e and spins 1/2 . It is believed that for any one-dimensional correlated electron system, low-lying electron excitations carry either only spin and no charge, or only charge without spin. That is why recent experiments looked for such low-lying collective electron excitations, one of which carries only spin, and the other carries only charge. Here we show that despite the fact that for exactly solvable one-dimensional correlated electron models there exist excitations which carry only spin and only charge, in all these models with short-range interactions the low-energy physics is described by low-lying collective excitations, one of which carries both spin and charge
Probing correlated quantum many-body systems at the single-particle level
International Nuclear Information System (INIS)
Endres, Manuel
2013-01-01
The detection of correlation and response functions plays a crucial role in the experimental characterization of quantum many-body systems. In this thesis, we present novel techniques for the measurement of such functions at the single-particle level. Specifically, we show the single-atom- and single-site-resolved detection of an ultracold quantum gas in an optical lattice. The quantum gas is described by the Bose-Hubbard model, which features a zero temperature phase transition from a superfluid to a Mott-insulating state, a paradigm example of a quantum phase transition. We used the aforementioned detection techniques to study correlation and response properties across the superfluid-Mott-insulator transition. The single-atom sensitivity of our method is achieved by fluorescence detection of individual atoms with a high signal-to-noise ratio. A high-resolution objective collects the fluorescence light and yields in situ 'snapshots' of the quantum gas that allow for a single-site-resolved reconstruction of the atomic distribution. This allowed us to measure two-site and non-local correlation-functions across the superfluid-Mott-insulator transition. Non-local correlation functions are based on the information of an extended region of the system and play an important role for the characterization of low-dimensional quantum phases. While non-local correlation functions were so far only theoretical tools, our results show that they are actually experimentally accessible. Furthermore, we used a new thermometry scheme, based on the counting of individual thermal excitations, to measure the response of the system to lattice modulation. Using this method, we studied the excitation spectrum of the system across the two-dimensional superfluid-Mott-insulator transition. In particular, we detected a 'Higgs' amplitude mode in the strongly-interacting superfluid close to the transition point where the system is described by an effectively Lorentz-invariant low-energy theory
Probing correlated quantum many-body systems at the single-particle level
Energy Technology Data Exchange (ETDEWEB)
Endres, Manuel
2013-02-27
The detection of correlation and response functions plays a crucial role in the experimental characterization of quantum many-body systems. In this thesis, we present novel techniques for the measurement of such functions at the single-particle level. Specifically, we show the single-atom- and single-site-resolved detection of an ultracold quantum gas in an optical lattice. The quantum gas is described by the Bose-Hubbard model, which features a zero temperature phase transition from a superfluid to a Mott-insulating state, a paradigm example of a quantum phase transition. We used the aforementioned detection techniques to study correlation and response properties across the superfluid-Mott-insulator transition. The single-atom sensitivity of our method is achieved by fluorescence detection of individual atoms with a high signal-to-noise ratio. A high-resolution objective collects the fluorescence light and yields in situ 'snapshots' of the quantum gas that allow for a single-site-resolved reconstruction of the atomic distribution. This allowed us to measure two-site and non-local correlation-functions across the superfluid-Mott-insulator transition. Non-local correlation functions are based on the information of an extended region of the system and play an important role for the characterization of low-dimensional quantum phases. While non-local correlation functions were so far only theoretical tools, our results show that they are actually experimentally accessible. Furthermore, we used a new thermometry scheme, based on the counting of individual thermal excitations, to measure the response of the system to lattice modulation. Using this method, we studied the excitation spectrum of the system across the two-dimensional superfluid-Mott-insulator transition. In particular, we detected a 'Higgs' amplitude mode in the strongly-interacting superfluid close to the transition point where the system is described by an effectively Lorentz
Muscular and systemic correlates of resistance training-induced muscle hypertrophy.
Mitchell, Cameron J; Churchward-Venne, Tyler A; Bellamy, Leeann; Parise, Gianni; Baker, Steven K; Phillips, Stuart M
2013-01-01
To determine relationships between post-exercise changes in systemic [testosterone, growth hormone (GH), insulin like grow factor 1 (IGF-1) and interleukin 6 (IL-6)], or intramuscular [skeletal muscle androgen receptor (AR) protein content and p70S6K phosphorylation status] factors in a moderately-sized cohort of young men exhibiting divergent resistance training-mediated muscle hypertrophy. Twenty three adult males completed 4 sessions•wk⁻¹ of resistance training for 16 wk. Muscle biopsies were obtained before and after the training period and acutely 1 and 5 h after the first training session. Serum hormones and cytokines were measured immediately, 15, 30 and 60 minutes following the first and last training sessions of the study. Mean fiber area increased by 20% (range: -7 to 80%; P<0.001). Protein content of the AR was unchanged with training (fold change = 1.17 ± 0.61; P=0.19); however, there was a significant correlation between the changes in AR content and fiber area (r=0.60, P=0.023). Phosphorylation of p70S6K was elevated 5 hours following exercise, which was correlated with gains in mean fiber area (r=0.54, P=0.007). There was no relationship between the magnitude of the pre- or post-training exercise-induced changes in free testosterone, GH, or IGF-1 concentration and muscle fiber hypertrophy; however, the magnitude of the post exercise IL-6 response was correlated with muscle hypertrophy (r=0.48, P=0.019). Post-exercise increases in circulating hormones are not related to hypertrophy following training. Exercise-induced changes in IL-6 correlated with hypertrophy, but the mechanism for the role of IL-6 in hypertrophy is not known. Acute increases, in p70S6K phosphorylation and changes in muscle AR protein content correlated with muscle hypertrophy implicating intramuscular rather than systemic processes in mediating hypertrophy.
Performance Analysis of Production Systems with Correlated Demand via Diffusion Approximations
Directory of Open Access Journals (Sweden)
Yingdong Lu
2012-01-01
Full Text Available We investigate the performance of a production system with correlated demand through diffusion approximation. The key performance metric under consideration is the extreme points that this system can reach. This problem is mapped to a problem of characterizing the joint probability density of a two-dimensional Brownian motion and its coordinate running maximum. To achieve this goal, we obtain the stationary distribution of a reflected Brownian motion within the positive quarter-plane, which is of independent interest, through investigating a solution of an extended Helmhotz equation.
BEC-BCS-laser crossover in Coulomb-correlated electron-hole-photon systems
International Nuclear Information System (INIS)
Yamaguchi, M; Kamide, K; Ogawa, T; Yamamoto, Y
2012-01-01
Many-body features caused by Coulomb correlations are of great importance for understanding phenomena pertaining to polariton systems in semiconductor microcavities, i.e. electron-hole-photon systems. Remarkable many-body effects are shown to exist in both thermal-equilibrium phases and non-equilibrium lasing states. We then show a unified framework for connecting the thermal-equilibrium and the non-equilibrium steady states based on a non-equilibrium Green's function approach. Bose-Einstein condensate (BEC)-Bardeen-Cooper-Schrieffer (BCS)-laser crossovers are investigated by using this approach. (paper)
Friction Factor Correlation for Regenerator Working in a Travelling-Wave Thermoacoustic System
Directory of Open Access Journals (Sweden)
Fatimah A. Z. Mohd Saat
2017-03-01
Full Text Available Regenerator is a porous solid structure which is important in the travelling-wave thermoacoustic system. It provides the necessary contact surface and thermal capacity for the working gas to undergo a thermodynamic cycle under acoustic oscillatory flow conditions. However, it also creates a pressure drop that could degrade the overall system performance. Ideally, in a travelling-wave system, the phase angle between oscillating pressure and velocity in the regenerator should be zero, or as close to zero as possible. In this study, the hydrodynamic condition of a regenerator has been investigated both experimentally (in a purpose-built rig providing a travelling-wave phasing and numerically. A two-dimensional ANSYS FLUENT CFD model, capturing the important features of the experimental conditions, has been developed. The findings suggest that a steady-state correlation, commonly used in designing thermoacoustic systems, is applicable provided that the travelling-wave phase angle is maintained. However, for coarse mesh regenerators, the results show interesting “phase shifting” phenomena, which may limit the correlation validity. Current experimental and CFD studies are important for predicting the viscous losses in future models of thermoacoustic systems.
International Nuclear Information System (INIS)
Vilardy, Juan M; Millán, María S; Pérez-Cabré, Elisabet; Torres, Yezid
2014-01-01
We propose a generalization of the encryption system based on double random phase encoding (DRPE) and a joint transform correlator (JTC), from the Fourier domain to the fractional Fourier domain (FrFD) by using the fractional Fourier operators, such as the fractional Fourier transform (FrFT), fractional traslation, fractional convolution and fractional correlation. Image encryption systems based on a JTC architecture in the FrFD usually produce low quality decrypted images. In this work, we present two approaches to improve the quality of the decrypted images, which are based on nonlinear processing applied to the encrypted function (that contains the joint fractional power spectrum, JFPS) and the nonzero-order JTC in the FrFD. When the two approaches are combined, the quality of the decrypted image is higher. In addition to the advantages introduced by the implementation of the DRPE using a JTC, we demonstrate that the proposed encryption system in the FrFD preserves the shift-invariance property of the JTC-based encryption system in the Fourier domain, with respect to the lateral displacement of both the key random mask in the decryption process and the retrieval of the primary image. The feasibility of this encryption system is verified and analyzed by computer simulations. (paper)
Disorder and pseudogap in strongly correlated systems: Phase diagram in the DMFT + Σ approach
International Nuclear Information System (INIS)
Kuleeva, N. A.; Kuchinskii, E. Z.
2013-01-01
The influence of disorder and pseudogap fluctuations on the Mott insulator-metal transition in strongly correlated systems has been studied in the framework of the generalized dynamic mean field theory (DMFT + Σ approach). Using the results of investigations of the density of states (DOS) and optical conductivity, a phase diagram (disorder-Hubbard interaction-temperature) is constructed for the paramagnetic Anderson-Hubbard model, which allows both the effects of strong electron correlations and the influence of strong disorder to be considered. Strong correlations are described using the DMFT, while a strong disorder is described using a generalized self-consistent theory of localization. The DOS and optical conductivity of the paramagnetic Hubbard model have been studied in a pseudogap state caused by antiferromagnetic spin (or charge) short-range order fluctuations with a finite correlation length, which have been modeled by a static Gaussian random field. The effect of a pseudogap on the Mott insulator-metal transition has been studied. It is established that, in both cases, the static Gaussian random field (related to the disorder or pseudogap fluctuations) leads to suppression of the Mott transition, broadening of the coexistence region of the insulator and metal phases, and an increase in the critical temperature at which the coexistence region disappears
Volatility and correlation-based systemic risk measures in the US market
Civitarese, Jamil
2016-10-01
This paper deals with the problem of how to use simple systemic risk measures to assess portfolio risk characteristics. Using three simple examples taken from previous literature, one based on raw and partial correlations, another based on the eigenvalue decomposition of the covariance matrix and the last one based on an eigenvalue entropy, a Granger-causation analysis revealed some of them are not always a good measure of risk in the S&P 500 and in the VIX. The measures selected do not Granger-cause the VIX index in all windows selected; therefore, in the sense of risk as volatility, the indicators are not always suitable. Nevertheless, their results towards returns are similar to previous works that accept them. A deeper analysis has shown that any symmetric measure based on eigenvalue decomposition of correlation matrices, however, is not useful as a measure of "correlation" risk. The empirical counterpart analysis of this proposition stated that negative correlations are usually small and, therefore, do not heavily distort the behavior of the indicator.
Correlation Of An E-Nose System For Odor Assessment Of Shoe/Sock Systems With A Human Sensory Panel
International Nuclear Information System (INIS)
Horras, Stephan; Reimann, Peter; Schuetze, Andreas; Gaiotto, Alessandra; Mayer, Maria
2009-01-01
Evaluation of strength and quality of smell is today still primarily done with human sensory panels. For a range of applications, technical systems for an objective smell assessment would provide a great benefit in R and D and also day-to-day application. The project presented here specifically addresses the problem of assessing the strength and unpleasantness of smell caused by sweat in shoes and socks by an E-nose system. The ultimate goal is to provide a tool for developing improved shoe/sock systems with optimized materials.The main approach to achieve this goal is to find a correlation between the assessment of a human sensory panel and the complex sensor response patterns of an E-Nose system to appraise the smell of sweat in shoes and socks. Therefore a range of test persons wear shoes and socks under defined ambient conditions in a controlled test environment as well as during everyday use. Afterwards the smell of the shoes and socks is both measured with the E-Nose system and assessed by a human sensory panel. We report here the results of the first larger test series and the identified correlation between the E-Nose system and the human assessment of the smell of sweat.
Detection system for neutron β decay correlations in the UCNB and Nab experiments
Energy Technology Data Exchange (ETDEWEB)
Broussard, L.J., E-mail: broussardlj@ornl.gov [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Zeck, B.A. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); North Carolina State University, Raleigh, NC 27695 (United States); Adamek, E.R. [Indiana University, Bloomington, IN 47405 (United States); Baeßler, S. [University of Virginia, Charlottesville, VA 22904 (United States); Birge, N. [University of Tennessee, Knoxville, TN 37996 (United States); Blatnik, M. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Cleveland State University, Cleveland, OH 44115 (United States); Bowman, J.D. [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Brandt, A.E. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); North Carolina State University, Raleigh, NC 27695 (United States); Brown, M. [University of Kentucky, Lexington, KY 40506 (United States); Burkhart, J. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Callahan, N.B. [Indiana University, Bloomington, IN 47405 (United States); Clayton, S.M. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Crawford, C. [University of Kentucky, Lexington, KY 40506 (United States); Cude-Woods, C. [North Carolina State University, Raleigh, NC 27695 (United States); Currie, S. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Dees, E.B. [North Carolina State University, Raleigh, NC 27695 (United States); Ding, X. [Virginia Polytechnic Institute & State University, Blacksburg, VA 24061 (United States); Fomin, N. [University of Tennessee, Knoxville, TN 37996 (United States); Frlez, E.; Fry, J. [University of Virginia, Charlottesville, VA 22904 (United States); and others
2017-03-21
We describe a detection system designed for precise measurements of angular correlations in neutron β decay. The system is based on thick, large area, highly segmented silicon detectors developed in collaboration with Micron Semiconductor, Ltd. The prototype system meets specifications for β electron detection with energy thresholds below 10 keV, energy resolution of ∼3 keV FWHM, and rise time of ∼50 ns with 19 of the 127 detector pixels instrumented. Using ultracold neutrons at the Los Alamos Neutron Science Center, we have demonstrated the coincident detection of β particles and recoil protons from neutron β decay. The fully instrumented detection system will be implemented in the UCNB and Nab experiments to determine the neutron β decay parameters B, a, and b.
Directory of Open Access Journals (Sweden)
Ignacio Santamaría
2008-04-01
Full Text Available This paper treats the identification of nonlinear systems that consist of a cascade of a linear channel and a nonlinearity, such as the well-known Wiener and Hammerstein systems. In particular, we follow a supervised identification approach that simultaneously identifies both parts of the nonlinear system. Given the correct restrictions on the identification problem, we show how kernel canonical correlation analysis (KCCA emerges as the logical solution to this problem. We then extend the proposed identification algorithm to an adaptive version allowing to deal with time-varying systems. In order to avoid overfitting problems, we discuss and compare three possible regularization techniques for both the batch and the adaptive versions of the proposed algorithm. Simulations are included to demonstrate the effectiveness of the presented algorithm.
A new multiparametry system for the acquisition, correlation and processing of nuclear data
International Nuclear Information System (INIS)
Toledo Acosta, Rene; Osorio Deliz, Juan F.; Arista Romeu, Eduardo; Arteche Diaz, Raul; Lopez Torres, Ernesto
1999-01-01
A four spectrometric channels multiparametry System for the acquisition, correlation and processing of nuclear data is described. The design was based upon an TMS320-5x DSP substituting the one developed with the 80C186 microprocessor. The current configuration is similar to the previous one since consists of a PC incorporates board, an signals adapter and the software for the processing of the information.The system can be used for the multiparametry analysis, in pulse height analysis or in any combination of both according to the necessities. The System facilitates the stabilization of the zeros of the A/D converters. The block outline of the electronic design is included and they stand out some functions of the system
Marquez-Barrientos, C; Liu, X C; Lyon, R; Tassone, C; Thometz, J; Tarima, S
2012-07-01
Several studies have attempted to measure how well external markers track internal bone movement using pins drilled into the foot, but this is too invasive for the pediatric population. This study investigated how well a six segment foot model (6SFM) using external markers was able to measure bone movement in the foot compared to MRI measurements. The foot was moved into different positions using a plastic foot jig and measurements were taken with both systems. The aims were to: (1) Look at the correlation between movement tracked with an Electronic Motion Tracking System (EMTS) and by measurements derived from MRI images, specifically the principal intercept angles (PIAs) which are the angles of intersection between principal axes of inertia of bone volumes. (2) To see how well external motion measured by the 6SFM could predict PIAs. Four bone pairs had their movement tracked: Tibia-Calcaneus, Calcaneus-Cuboid, Navicular-1st Metatarsal, and 1st Metatarsal-Hallux. The results showed moderate correlation between measured PIAs and those predicted at the Tibia-Calcaneus, Navicular-1st Metatarsal, and 1st Metatarsal-Hallux joints. Moderate to high correlation was found between the PIA and movement in a single anatomic plane for all four joints at several positions. The 6SFM using the EMTS allows reliable tracking of 3D rotations in the pediatric foot, except at the Calcaneus-Cuboid joint. Copyright © 2012 Elsevier B.V. All rights reserved.
Theoretical development and first-principles analysis of strongly correlated systems
Energy Technology Data Exchange (ETDEWEB)
Liu, Chen [Iowa State Univ., Ames, IA (United States)
2016-12-17
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 an 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.
Directory of Open Access Journals (Sweden)
Ning Yin
Full Text Available To evaluate a comprehensive scoring system which combines clinical manifestations of Pierre Robin Sequence (PRS including severity of breathing difficulties, body weight and preoperative Cormack-Lehane grade, for its correlation with perioperative PRS airway management decision.Forty PRS children were retrospectively recruited after surgery. Specialists examined all subjects and scored for clinical manifestations (1´ - 4´, weight gain (1´- 4´, dyspnea scores (1´- 4´, and Cormack-Lehane grade (1´- 4´. The correlation of the integrated scores and the necessity of endotracheal intubation or laryngeal mask application were analyzed. In addition, the score correlation with postoperative dyspnea and/or low pulse oxygen saturation (SPO2 levels after extubation was determined.In our study every individual patient had a score from 0´ to 16´, while the higher in the numbers represented higher risk of breathing difficulty. All patients with comprehensive scores 13 points required a laryngeal mask assisted airway management and were considered to have difficult airways. Dyspnea after extubation and postoperative low SPO2 occurred among patients who scored over 10 points.In PRS patients, preoperative weight gaining status and severity of dyspnea in combination with Cormack-Lehane classification provide a scoring system that could help to optimize airway management decisions such as endotracheal intubation or laryngeal mask airway placement and has the potential to predict postoperative dyspnea or low SPO2 levels.
Correlations in clusters and related systems. New perspectives on the many-body problem
International Nuclear Information System (INIS)
Connerade, J.P.
1996-01-01
The contents of the present volume are the proceedings of an Adriatico Research Conference, held at the International Centre for Theoretical Physics in Trieste from 26 to 29 July 1994. The theme of the conference covered many aspects of cooperative effects, beginning with giant resonances in many-electron systems, and particularly in new objects such as metallic clusters, in which collective electron dynamics are a novel feature. The relationship of these resonances with comparable features in nuclear and solid state physics was extensively discussed. Related effects, such as instabilities of valence both in clusters and in solids were explored. Clusters allow one to track the evolution of certain properties from the free atom to the solid state limits as a function of size. The giant resonances concerned not only intra-atomic excitations, but also correlated motions of all delocalized electrons within the cluster. Other systems with unusual properties, such as negative ions, in which correlations play an important role, were also considered. Finally, dynamical effects and the possible interactions between electron-electron correlations and high laser fields were envisaged
International Nuclear Information System (INIS)
Mistretta, J.
1988-01-01
The EMRIC set up (Ensemble de Mesure Rapide pour l'Interferometrie et les Correlations) is devoted to the study of space and time extent of nuclear sources from the measurement of light charged particles correlations. This device, composed of an array of 16 detectors (CsI crystals coupled to phototubes) used in conjunction with a multiwire chamber, is characterised by a smart granulation, a large solid angle and very small detection dead areas. It opens new possibilities in the measurement of the correlation functions (complete determination (modulus and direction) of the relative momenta in the range 1 to 100 MeV/c). This work describes the development and performances of EMRIC. The mechanics and electronics are detailed to enlighten difficulties inherent to this type of detector. An auxiliary monitoring system has been carried out to simplify some of the experimental tasks. A simulation software code has been written (based on Monte-Carlo techniques) to simulate the effect of the detector on the experimental data. The precision and efficiency in detection place EMRIC, which can be operated in the whole intermediate energy range (10-100 MeV/u), among the most powerful existing devices. First results on the 20 Ne + 27 Al system are finally shown [fr
Atomic physics of strongly correlated systems: Progress report, 1 February 1988--15 January 1989
International Nuclear Information System (INIS)
Lin Chii-Dong.
1989-01-01
This report presents the progress made in our continuing study of strongly correlated atomic systems for the last contract period. In the area of hyperspherical coordinates for Coulombic three-body systems of arbitrary masses a general computing code has been developed. Calculation of the adiabatic potential curves have been accomplished for the e/sup /minus//e + e/sup /minus// system of arbitrary L, S and parity π. It was found that these curves behave very similar to the potential curves of H/sup /minus// except for a mass scaling. We have also examined the mass dependence of the ground state potential curves for systems of three charged particles, AAB, and showed that the curves become more attractive as the mass m/sub A/ becomes larger than m/sub B/. For ion-atom collisions we have examined the transfer-excitation (TE) processes to establish the importance of electron correlations in these two-electron transitions. We have also examined the orientation parameters for excited states formed in collisions with positive and negative charged particles to establish the relation between the sign of the charge of the incident particles to the sign of
International Nuclear Information System (INIS)
Backes, Steffen
2017-04-01
The study of the electronic properties of correlated systems is a very diverse field and has lead to valuable insight into the physics of real materials. In these systems, the decisive factor that governs the physical properties is the ratio between the electronic kinetic energy, which promotes delocalization over the lattice, and the Coulomb interaction, which instead favours localized electronic states. Due to this competition, correlated electronic systems can show unique and interesting properties like the Metal-Insulator transition, diverse phase diagrams, strong temperature dependence and in general a high sensitivity to the environmental conditions. A theoretical description of these systems is not an easy task, since perturbative approaches that do not preserve the competition between the kinetic and interaction terms can only be applied in special limiting cases. One of the most famous approaches to obtain the electronic properties of a real material is the ab initio density functional theory (DFT) method. It allows one to obtain the ground state density of the system under investigation by mapping onto an effective non-interacting system that has to be found self-consistently. While being an exact theory, in practical implementations certain approximations have to be made to the exchange-correlation potential. The local density approximation (LDA), which approximates the exchange-correlation contribution to the total energy by that of a homogeneous electron gas with the corresponding density, has proven quite successful in many cases. Though, this approximation in general leads to an underestimation of electronic correlations and is not able to describe a metal-insulator transition due to electronic localization in the presence of strong Coulomb interaction. A different approach to the interacting electronic problem is the dynamical mean-field theory (DMFT), which is non-perturbative in the kinetic and interaction term but neglects all non
Energy Technology Data Exchange (ETDEWEB)
Backes, Steffen
2017-04-15
The study of the electronic properties of correlated systems is a very diverse field and has lead to valuable insight into the physics of real materials. In these systems, the decisive factor that governs the physical properties is the ratio between the electronic kinetic energy, which promotes delocalization over the lattice, and the Coulomb interaction, which instead favours localized electronic states. Due to this competition, correlated electronic systems can show unique and interesting properties like the Metal-Insulator transition, diverse phase diagrams, strong temperature dependence and in general a high sensitivity to the environmental conditions. A theoretical description of these systems is not an easy task, since perturbative approaches that do not preserve the competition between the kinetic and interaction terms can only be applied in special limiting cases. One of the most famous approaches to obtain the electronic properties of a real material is the ab initio density functional theory (DFT) method. It allows one to obtain the ground state density of the system under investigation by mapping onto an effective non-interacting system that has to be found self-consistently. While being an exact theory, in practical implementations certain approximations have to be made to the exchange-correlation potential. The local density approximation (LDA), which approximates the exchange-correlation contribution to the total energy by that of a homogeneous electron gas with the corresponding density, has proven quite successful in many cases. Though, this approximation in general leads to an underestimation of electronic correlations and is not able to describe a metal-insulator transition due to electronic localization in the presence of strong Coulomb interaction. A different approach to the interacting electronic problem is the dynamical mean-field theory (DMFT), which is non-perturbative in the kinetic and interaction term but neglects all non
Pion correlations in relativistic heavy ion collisions at Heavy Ion Spectrometer Systems (HISS)
Energy Technology Data Exchange (ETDEWEB)
Christie, W.B. Jr.
1990-05-01
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 is 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.
Phase-Covariant Cloning and EPR Correlations in Entangled Macroscopic Quantum Systems
de Martini, Francesco; Sciarrino, Fabio
2007-03-01
Theoretical and experimental results on the Quantum Injected Optical Parametric Amplification (QI-OPA) of optical qubits in the high gain regime are reported. The large size of the gain parameter in the collinear configuration, g = 4.5, allows the generation of EPR nonlocally correlated bunches containing about 4000 photons. The entanglement of the related Schroedinger Cat-State (SCS) is demonstrated as well as the establishment of Phase-Covariant quantum cloning. The cloning ``fidelity'' has been found to match the theoretical results. According to the original 1935 definition of the SCS, the overall apparatus establishes for the first time the nonlocal correlations between a microcopic spin (qubit) and a high J angular momentum i.e. a mesoscopic multiparticle system close to the classical limit. The results of the first experimental realization of the Herbert proposal for superluminal communication via nonlocality will be presented.
Phase correlation and clustering of a nearest neighbour coupled oscillators system
International Nuclear Information System (INIS)
EI-Nashar, Hassan F.
2002-09-01
We investigated the phases in a system of nearest neighbour coupled oscillators before complete synchronization in frequency occurs. We found that when oscillators under the influence of coupling form a cluster of the same time-average frequency, their phases start to correlate. An order parameter, which measures this correlation, starts to grow at this stage until it reaches maximum. This means that a time-average phase locked state is reached between the oscillators inside the cluster of the same time- average frequency. At this strength the cluster attracts individual oscillators or a cluster to join in. We also observe that clustering in averaged frequencies orders the phases of the oscillators. This behavior is found at all the transition points studied. (author)
Phase correlation and clustering of a nearest neighbour coupled oscillators system
Ei-Nashar, H F
2002-01-01
We investigated the phases in a system of nearest neighbour coupled oscillators before complete synchronization in frequency occurs. We found that when oscillators under the influence of coupling form a cluster of the same time-average frequency, their phases start to correlate. An order parameter, which measures this correlation, starts to grow at this stage until it reaches maximum. This means that a time-average phase locked state is reached between the oscillators inside the cluster of the same time- average frequency. At this strength the cluster attracts individual oscillators or a cluster to join in. We also observe that clustering in averaged frequencies orders the phases of the oscillators. This behavior is found at all the transition points studied.
Energy Technology Data Exchange (ETDEWEB)
Meisel, D
1975-07-15
Recent experimental data concerning the rate constants for electron transfer reactions of organic systems in aqueous solutions and their equilibrium constants is examined for possible correlation. The data is correlated quite well by the Marcus theory, if a reorganization parameter, lambda, of 18 kcal/mole is used. Assuming that the only contribution to lambda is the free energy of rearrangement of the water molecules, an effective radius of 5 A for the reacting entities is estimated. For the zero free energy change reaction, i.e., electron exchange between a radical ion and its parent molecule, a rate constant of about 5 X 10/sup 7/ M/sup -1/ s/sup -1/ is predicted. (auth)
Serum Zinc Level and Its Correlation with Vesikari System Scoring in Acute Pediatric Diarrhea.
Eskander, Ayman E; Sherif, Lobna S; Nabih, Mohammad; Baroudy, Nevine R El; Marcos, Ghobrial C; Badawy, Ehsan A; Refay, Amira S El
2017-08-15
Diarrhea remains the most common infectious disease worldwide. Zinc has been studied extensively recently for its potential effect on prevention, control and treatment of acute diarrhoea. This study was designed to correlate the level of zinc with the severity of pediatric diarrhoea estimated by Vesikari Scoring System. The present study included 80 children aged two months to 30 months from those suffering from the acute diarrheal episode and admitted to Pediatric Hospital "Abo El Rish" Cairo University. Serum Zinc level was assessed by a colorimetric method with a spectrophotometer. Zinc deficiency was detected in 45 (56.2%) patient of the studied group Significant negative correlations were found between serum zinc level and severity of dehydration and duration of hospitalization (p Zinc level has an essential role in acute pediatric diarrhoea. Zinc therapy should be considered beside Oral rehydration salts (ORS) to achieve maximum impact on diarrheal diseases; clinical trials are recommended to support the zinc supplementation in developing countries.
φφ Back-to-Back Correlations in Finite Expanding Systems
International Nuclear Information System (INIS)
Padula, S. S.; Krein, G.; Hama, Y.; Panda, P. K.; Csoergo, T.
2006-01-01
Back-to-Back Correlations (BBC) of particle-antiparticle pairs are predicted to appear if hot and dense hadronic matter is formed in high energy nucleus-nucleus collisions. The BBC are related to in-medium mass-modification and squeezing of the quanta involved. Although the suppression of finite emission times were already known, the effects of finite system sizes and of collective phenomena had not been studied yet. Thus, for testing the survival and magnitude of the effect in more realistic situations, we study the BBC when mass-modification occurs in a finite sized, thermalized medium, considering a non-relativistically expanding fireball with finite emission time, and evaluating the width of the back-to-back correlation function. We show that the BBC signal indeed survives the expansion and flow effects, with sufficient magnitude to be observed at RHIC
Feature-based alert correlation in security systems using self organizing maps
Kumar, Munesh; Siddique, Shoaib; Noor, Humera
2009-04-01
The security of the networks has been an important concern for any organization. This is especially important for the defense sector as to get unauthorized access to the sensitive information of an organization has been the prime desire for cyber criminals. Many network security techniques like Firewall, VPN Concentrator etc. are deployed at the perimeter of network to deal with attack(s) that occur(s) from exterior of network. But any vulnerability that causes to penetrate the network's perimeter of defense, can exploit the entire network. To deal with such vulnerabilities a system has been evolved with the purpose of generating an alert for any malicious activity triggered against the network and its resources, termed as Intrusion Detection System (IDS). The traditional IDS have still some deficiencies like generating large number of alerts, containing both true and false one etc. By automatically classifying (correlating) various alerts, the high-level analysis of the security status of network can be identified and the job of network security administrator becomes much easier. In this paper we propose to utilize Self Organizing Maps (SOM); an Artificial Neural Network for correlating large amount of logged intrusion alerts based on generic features such as Source/Destination IP Addresses, Port No, Signature ID etc. The different ways in which alerts can be correlated by Artificial Intelligence techniques are also discussed. . We've shown that the strategy described in the paper improves the efficiency of IDS by better correlating the alerts, leading to reduced false positives and increased competence of network administrator.
Exact results relating spin-orbit interactions in two-dimensional strongly correlated systems
Kucska, Nóra; Gulácsi, Zsolt
2018-06-01
A 2D square, two-bands, strongly correlated and non-integrable system is analysed exactly in the presence of many-body spin-orbit interactions via the method of Positive Semidefinite Operators. The deduced exact ground states in the high concentration limit are strongly entangled, and given by the spin-orbit coupling are ferromagnetic and present an enhanced carrier mobility, which substantially differs for different spin projections. The described state emerges in a restricted parameter space region, which however is clearly accessible experimentally. The exact solutions are provided via the solution of a matching system of equations containing 74 coupled, non-linear and complex algebraic equations. In our knowledge, other exact results for 2D interacting systems with spin-orbit interactions are not present in the literature.
Electron-correlated fragment-molecular-orbital calculations for biomolecular and nano systems.
Tanaka, Shigenori; Mochizuki, Yuji; Komeiji, Yuto; Okiyama, Yoshio; Fukuzawa, Kaori
2014-06-14
Recent developments in the fragment molecular orbital (FMO) method for theoretical formulation, implementation, and application to nano and biomolecular systems are reviewed. The FMO method has enabled ab initio quantum-mechanical calculations for large molecular systems such as protein-ligand complexes at a reasonable computational cost in a parallelized way. There have been a wealth of application outcomes from the FMO method in the fields of biochemistry, medicinal chemistry and nanotechnology, in which the electron correlation effects play vital roles. With the aid of the advances in high-performance computing, the FMO method promises larger, faster, and more accurate simulations of biomolecular and related systems, including the descriptions of dynamical behaviors in solvent environments. The current status and future prospects of the FMO scheme are addressed in these contexts.
The ALPS project release 2.0: open source software for strongly correlated systems
International Nuclear Information System (INIS)
Bauer, B; Gamper, L; Gukelberger, J; Hehn, A; Isakov, S V; Ma, P N; Mates, P; Carr, L D; Evertz, H G; Feiguin, A; Freire, J; Koop, D; Fuchs, S; Gull, E; Guertler, S; Igarashi, R; Matsuo, H; Parcollet, O; Pawłowski, G; Picon, J D
2011-01-01
We present release 2.0 of the ALPS (Algorithms and Libraries for Physics Simulations) project, an open source software project to develop libraries and application programs for the simulation of strongly correlated quantum lattice models such as quantum magnets, lattice bosons, and strongly correlated fermion systems. The code development is centered on common XML and HDF5 data formats, libraries to simplify and speed up code development, common evaluation and plotting tools, and simulation programs. The programs enable non-experts to start carrying out serial or parallel numerical simulations by providing basic implementations of the important algorithms for quantum lattice models: classical and quantum Monte Carlo (QMC) using non-local updates, extended ensemble simulations, exact and full diagonalization (ED), the density matrix renormalization group (DMRG) both in a static version and a dynamic time-evolving block decimation (TEBD) code, and quantum Monte Carlo solvers for dynamical mean field theory (DMFT). The ALPS libraries provide a powerful framework for programmers to develop their own applications, which, for instance, greatly simplify the steps of porting a serial code onto a parallel, distributed memory machine. Major changes in release 2.0 include the use of HDF5 for binary data, evaluation tools in Python, support for the Windows operating system, the use of CMake as build system and binary installation packages for Mac OS X and Windows, and integration with the VisTrails workflow provenance tool. The software is available from our web server at http://alps.comp-phys.org/
Teijeiro, E J; Macías, R J; Morales, J M; Guerra, E; López, G; Alvarez, L M; Fernández, F; Maragoto, C; Seijo, F; Alvarez, E
The Neurosurgical Deep Recording System (NDRS) using a personal computer takes the place of complex electronic equipment for recording and processing deep cerebral electrical activity, as a guide in stereotaxic functional neurosurgery. It also permits increased possibilities of presenting information in direct graphic form with automatic management and sufficient flexibility to implement different analyses. This paper describes the possibilities of automatic simultaneous graphic representation in three almost orthogonal planes, available with the new 5.1 version of NDRS so as to facilitate the analysis of anatomophysiological correlation in the localization of deep structures of the brain during minimal access surgery. This new version can automatically show the spatial behaviour of signals registered throughout the path of the electrode inside the brain, superimposed simultaneously on sagittal, coronal and axial sections of an anatomical atlas of the brain, after adjusting the scale automatically according to the dimensions of the brain of each individual patient. This may also be shown in a tridimensional representation of the different planes themselves intercepting. The NDRS system has been successfully used in Spain and Cuba in over 300 functional neurosurgery operations. The new version further facilitates analysis of spatial anatomophysiological correlation for the localization of brain structures. This system has contributed to increase the precision and safety in selecting surgical targets in the control of Parkinson s disease and other disorders of movement.
Correlation between Rock mass rating, Q-system and Rock mass index based on field data
Directory of Open Access Journals (Sweden)
Soufi Amine
2018-01-01
The proposed regression models reveal strong correlations between RMR, Q and RMi indexes with high values of accuracy coefficients so that they can be used to estimate the “CPB3” underground rock mass quality for the range of RMR between 30% and 80%. The developed mathematical formulations of the geomechanicalindexes will certainly offer an effective tool to geologist and geotechnical professionals in the decision-making process, preliminary design phase, stability problems and suggestions of the required supporting system and techniques without the expense of more resources or time.
Reliability Worth Analysis of Distribution Systems Using Cascade Correlation Neural Networks
DEFF Research Database (Denmark)
Heidari, Alireza; Agelidis, Vassilios; Pou, Josep
2018-01-01
Reliability worth analysis is of great importance in the area of distribution network planning and operation. The reliability worth's precision can be affected greatly by the customer interruption cost model used. The choice of the cost models can change system and load point reliability indices....... In this study, a cascade correlation neural network is adopted to further develop two cost models comprising a probabilistic distribution model and an average or aggregate model. A contingency-based analytical technique is adopted to conduct the reliability worth analysis. Furthermore, the possible effects...
Mathematical correlation of modal-parameter-identification methods via system-realization theory
Juang, Jer-Nan
1987-01-01
A unified approach is introduced using system-realization theory to derive and correlate modal-parameter-identification methods for flexible structures. Several different time-domain methods are analyzed and treated. A basic mathematical foundation is presented which provides insight into the field of modal-parameter identification for comparison and evaluation. The relation among various existing methods is established and discussed. This report serves as a starting point to stimulate additional research toward the unification of the many possible approaches for modal-parameter identification.
Mathematical correlation of modal parameter identification methods via system realization theory
Juang, J. N.
1986-01-01
A unified approach is introduced using system realization theory to derive and correlate modal parameter identification methods for flexible structures. Several different time-domain and frequency-domain methods are analyzed and treated. A basic mathematical foundation is presented which provides insight into the field of modal parameter identification for comparison and evaluation. The relation among various existing methods is established and discussed. This report serves as a starting point to stimulate additional research towards the unification of the many possible approaches for modal parameter identification.
International Nuclear Information System (INIS)
La Ville, J.L.; Bizard, G.; Durand, D.; Jin, G.M.; Rosato, E.
1990-06-01
Light fragment emission, when triggered by large transverse momentum protons shows specific kinematical correlations due to recoil effects of the excited emitting source. Such effects have been observed in azimuthal angular distributions of He-particles produced in collisions induced by 94 MeV/u 16 0 ions on Al, Ni and Au targets. A model calculation assuming a two-stage mechanism (formation and sequential decay of a hot source) gives a good description of these whole data. From this succesfull confrontation, it is possible to estimate the size of the emitting system
Microscopic origin of marginal Fermi-liquid in strongly correlated spin systems
International Nuclear Information System (INIS)
Protogenov, A.P.; Ryndyk, D.A.
1992-08-01
We consider the consequences of separation of spin and charge degrees of freedom in 2+1D strongly correlated spin systems. Self-consistent spin and charge motions induced by doping in sites of ground and dual lattices form such a spectrum of quasiparticles which together with the dispersionless character of the collective excitation spectrum and the chemical potential pinning in the band centre yield the necessary behavior of charge and spin polarizability to support the theory of marginal liquid formulated by C.M. Varma et al. (Phys. Rev. Lett. 63, 1996 (1989)). (author). 28 refs, 4 figs
A white–cyan-red LED system for low correlated colour temperature lighting
DEFF Research Database (Denmark)
Chakrabarti, Maumita; Thorseth, Anders; Corell, Dennis Dan
2015-01-01
A white LED complemented by cyan and red LEDs is a good candidate for achieving high colour rendering at low correlated colour temperatures. This is usually very difficult with commercially available white LEDs. In addition, the system is able to replace incandescent lighting in many applications...... to 2400 K. Within this range the white light is characterized by a high general colour rendering index (Ra>90), special colour rendering indices for saturated red objects (R9>85), and low chromaticity distance (Duv) from the Planckian locus (Duv
Enhancement of Quantum Correlations in Qubit-Qutrit Systems under the non-Markovian Environment
Institute of Scientific and Technical Information of China (English)
Abdul Basit; Hamad Ali; Fazal Badshah; Guo-Qin Ge
2017-01-01
We investigate the time evolution of quantum correlations of a hybrid qubit-qutrit system under the classical Ornstein-Uhlenbeck (OU) noise.Here we consider two different one-parameter families of qubit-qutrit states which independently interact with the non-Markovian reservoirs.A comparison with the Markovian dynamics reveals that for the same set of initial condition parameters,the non-Markovian behavior of the environment plays an important role in the enhancement of the survival time of quantum correlations.In addition,it is observed that the non-Markovian strength (γ/F) has a positive impact on the correlations time.For the initial separable states it is found that there is a finite time interval in which the geometric quantum discord is frozen despite the presence of a noisy environment and that interval can be further prolonged by using the non-Markovian property.Moreover,its decay can be significantly delayed.
Eschler, Anica; Rösler, Klaus; Rotter, Robert; Gradl, Georg; Mittlmeier, Thomas; Gierer, Philip
2014-09-01
The classification system of Rockwood and Young is a commonly used classification for acromioclavicular joint separations subdividing types I-VI. This classification hypothesizes specific lesions to anatomical structures (acromioclavicular and coracoclavicular ligaments, capsule, attached muscles) leading to the injury. In recent literature, our understanding for anatomical correlates leading to the radiological-based Rockwood classification is questioned. The goal of this experimental-based investigation was to approve the correlation between the anatomical injury pattern and the Rockwood classification. In four human cadavers (seven shoulders), the acromioclavicular and coracoclavicular ligaments were transected stepwise. Radiological correlates were recorded (Zanca view) with 15-kg longitudinal tension applied at the wrist. The resulting acromio- and coracoclavicular distances were measured. Radiographs after acromioclavicular ligament transection showed joint space enlargement (8.6 ± 0.3 vs. 3.1 ± 0.5 mm, p acromioclavicular joint space width increased to 16.7 ± 2.7 vs. 8.6 ± 0.3 mm, p acromioclavicular joint lesions higher than Rockwood type I and II. The clinical consequence for reconstruction of low-grade injuries might be a solely surgical approach for the acromioclavicular ligaments or conservative treatment. High-grade injuries were always based on additional structural damage to the coracoclavicular ligaments. Rockwood type V lesions occurred while muscle attachments were intact.
Wang, Huiqin; Wang, Xue; Lynette, Kibe; Cao, Minghua
2018-06-01
The performance of multiple-input multiple-output wireless optical communication systems that adopt Q-ary pulse position modulation over spatial correlated log-normal fading channel is analyzed in terms of its un-coded bit error rate and ergodic channel capacity. The analysis is based on the Wilkinson's method which approximates the distribution of a sum of correlated log-normal random variables to a log-normal random variable. The analytical and simulation results corroborate the increment of correlation coefficients among sub-channels lead to system performance degradation. Moreover, the receiver diversity has better performance in resistance of spatial correlation caused channel fading.
Correlations between chaos in a perturbed sine-Gordon equation and a truncated model system
International Nuclear Information System (INIS)
Bishop, A.R.; Flesch, R.; Forests, M.G.; Overman, E.A.
1990-01-01
The purpose of this paper is to present a first step toward providing coordinates and associated dynamics for low-dimensional attractors in nearly integrable partial differential equations (pdes), in particular, where the truncated system reflects salient geometric properties of the pde. This is achieved by correlating: (1) numerical results on the bifurcations to temporal chaos with spatial coherence of the damped, periodically forced sine-Gordon equation with periodic boundary conditions; (2) an interpretation of the spatial and temporal bifurcation structures of this perturbed integrable system with regard to the exact structure of the sine-Gordon phase space; (3) a model dynamical systems problem, which is itself a perturbed integrable Hamiltonian system, derived from the perturbed sine-Gordon equation by a finite mode Fourier truncation in the nonlinear Schroedinger limit; and (4) the bifurcations to chaos in the truncated phase space. In particular, a potential source of chaos in both the pde and the model ordinary differential equation systems is focused on: the existence of homoclinic orbits in the unperturbed integrable phase space and their continuation in the perturbed problem. The evidence presented here supports the thesis that the chaotic attractors of the weakly perturbed periodic sine-Gordon system consists of low-dimensional metastable attacking states together with intermediate states that are O(1) unstable and correspond to homoclinic states in the integrable phase space. It is surmised that the chaotic dynamics on these attractors is due to the perturbation of these homocline integrable configurations
Bahrehmand, F; Vaisi-Raygani, A; Kiani, A; Rahimi, Z; Tavilani, H; Ardalan, M; Vaisi-Raygani, H; Shakiba, E; Pourmotabbed, T
2015-05-01
Systemic lupus erythematosus (SLE) is an autoimmune disease that involves multiple organs and is characterized by persistent systemic inflammation. Among the effects of inflammatory mediators, the induction of matrix metalloproteinases-2 and -9 (MMP-2 and MMP-9) and oxidative stress has been demonstrated to be important in the development of SLE. In this study, the possible association between MMP-9 and MMP-2 functional promoter polymorphism, stress, and inflammatory markers with development of severe cardiovascular disease (CVD), high blood pressure (HBP), and lupus nephropathy (LN) in SLE patients was investigated. The present case-control study consisted of 109 SLE patients with and without CVD, HBP and LN and 101 gender- and age-matched unrelated healthy controls from a population in western Iran. MMP-2 -G1575A and MMP-9 -C1562T polymorphisms were detected by PCR-RFLP, serum MMP-2 and MMP-9, neopterin, malondialdehyde (MDA) and lipid levels were determined by ELISA, HPLC and enzyme assay, respectively. We found that MMP-9 -C1562 T and MMP-2 -G1575A alleles act synergistically to increase the risk of SLE by 2.98 times (p = 0.015). Findings of this study also demonstrated that there is a significant increase in the serum levels of MMP-2, neopterin and MDA and a significant decrease in serum level of MMP-9 in the presence of MMP-9-C1562 T and MMP-2 -G1575A alleles in SLE patients compared to controls. Further, SLE patients with MMP-9 (C/T + T/T) genotype had significantly higher serum concentrations of MMP-2, neopterin, MDA and LDL-C, but lower serum MMP-9 and HDL-C levels than corresponding members of the control group. MMP-9 (C/T + T/T) genotype increased risk of hypertension in SLE patients 2.71-fold. This study for the first time not only suggests that MMP-9 -C1562 T and MMP-2 -G1575A alleles synergistically increase the risk of SLE but also high serum levels of MDA, neopterin, and circulatory levels of MMP-2 and lower MMP-9 in SLE patients. This
Muscular and systemic correlates of resistance training-induced muscle hypertrophy.
Directory of Open Access Journals (Sweden)
Cameron J Mitchell
Full Text Available PURPOSE: To determine relationships between post-exercise changes in systemic [testosterone, growth hormone (GH, insulin like grow factor 1 (IGF-1 and interleukin 6 (IL-6], or intramuscular [skeletal muscle androgen receptor (AR protein content and p70S6K phosphorylation status] factors in a moderately-sized cohort of young men exhibiting divergent resistance training-mediated muscle hypertrophy. METHODS: Twenty three adult males completed 4 sessions•wk⁻¹ of resistance training for 16 wk. Muscle biopsies were obtained before and after the training period and acutely 1 and 5 h after the first training session. Serum hormones and cytokines were measured immediately, 15, 30 and 60 minutes following the first and last training sessions of the study. RESULTS: Mean fiber area increased by 20% (range: -7 to 80%; P<0.001. Protein content of the AR was unchanged with training (fold change = 1.17 ± 0.61; P=0.19; however, there was a significant correlation between the changes in AR content and fiber area (r=0.60, P=0.023. Phosphorylation of p70S6K was elevated 5 hours following exercise, which was correlated with gains in mean fiber area (r=0.54, P=0.007. There was no relationship between the magnitude of the pre- or post-training exercise-induced changes in free testosterone, GH, or IGF-1 concentration and muscle fiber hypertrophy; however, the magnitude of the post exercise IL-6 response was correlated with muscle hypertrophy (r=0.48, P=0.019. CONCLUSION: Post-exercise increases in circulating hormones are not related to hypertrophy following training. Exercise-induced changes in IL-6 correlated with hypertrophy, but the mechanism for the role of IL-6 in hypertrophy is not known. Acute increases, in p70S6K phosphorylation and changes in muscle AR protein content correlated with muscle hypertrophy implicating intramuscular rather than systemic processes in mediating hypertrophy.
PREFACE: Many-body correlations from dilute to dense nuclear systems
Otsuka, Takaharu; Urban, Michael; Yamada, Taiichi
2011-09-01
The International EFES-IN2P3 conference on "Many body correlations from dilute to dense nuclear systems" was held at the Institut Henri Poincaré (IHP), Paris, France, from 15-18 February 2011, on the occasion of the retirement of our colleague Peter Schuck. Correlations play a decisive role in various many-body systems such as nuclear systems, condensed matter and quantum gases. Important examples include: pairing correlations (Cooper pairs) which give rise to nuclear superfluidity (analogous to superconductivity in condensed matter); particle-hole (RPA) correlations in the description of the ground state beyond mean-field theory; clusters; and α-particle correlations in certain nuclei. Also, the nucleons themselves can be viewed as clusters of three quarks. During the past few years, researchers have started to study how the character of these correlations changes with the variation of the density. For instance, the Cooper pairs in dense matter can transform into a Bose-Einstein condensate (BEC) of true bound states at low density (this is the BCS-BEC crossover studied in ultracold Fermi gases). Similar effects play a role in neutron matter at low density, e.g., in the "neutron skin" of exotic nuclei. The α-cluster correlation becomes particularly important at lower density, such as in the excited states of some nuclei (e.g., the α-condensate-like structure in the Hoyle state of 12C) or in the formation of compact stars. In addition to nuclear physics, topics from astrophysics (neutron stars), condensed matter, and quantum gases were discussed in 48 talks and 19 posters, allowing the almost 90 participants from different communities to exchange their ideas, experiences and methods. The conference dinner took place at the Musée d'Orsay, and all the participants enjoyed the very pleasant atmosphere. One session of the conference was dedicated to the celebration of Peter's retirement. We would like to take this opportunity to wish Peter all the best and we hope
Sato, Lucy T; Kayser, Cristiane; Andrade, Luís E C
2009-01-01
The aim of this study was to correlate quantitative and semiquantitative nailfold capillaroscopy (NFC) parameters with the extent of cutaneous and visceral involvement in systemic sclerosis (SSc) patients. The presence of clinical and serological alterations was evaluated retrospectively and correlated with NFC findings (number of capillary loops/mm, vascular deletion score and number of enlarged and giant capillary loops). For evaluation of disease extension five manifestations were analyzed: finger pad lesions, skin involvement, esophageal involvement, interstitial lung disease, and pulmonary hypertension. There were 105 NFC examinations in 92 patients, 13 of whom were evaluated at two different time points. Patients with diffuse cutaneous SSc had a higher vascular deletion score than patients with limited cutaneous SSc, sine scleroderma SSc, and overlap syndrome (1.67+/-0.91 vs 0.99+/-0.82; p=0.0005). Modified Rodnan's skin score correlated positively with capillary deletion, evaluated by the vascular deletion score and the number of capillary loops/mm (p<0.001 and p=0.012; respectively). Patients with three or more involved tracts presented lower number of capillary loops/mm (8.00+/-1.69 vs 9.23+/-1.31 capillary loops/mm; p=0.025) and a higher vascular deletion score (1.41+/-0.95 vs 0.73+/-0.76; p=0.027) when compared to patients with less than three affected tracts. Vascular deletion score was significantly higher in patients with anti-Scl-70 antibodies that in patients without anti-Scl-70 antibodies (p=0.02). NFC abnormalities correlated positively with the diffuse form of SSc, the degree of cutaneous involvement, the number of affected tracts, and the presence of anti-Scl-70 antibodies.
Zhou, Nan; Pan, Ting; Zhang, Junsong; Li, Qianwen; Zhang, Xue; Bai, Chuan; Huang, Feng; Peng, Tao; Zhang, Jianhua; Liu, Chao; Tao, Liang; Zhang, Hui
2016-01-01
Ebola virus infection can cause severe hemorrhagic fever with a high mortality in humans. The outbreaks of Ebola viruses in 2014 represented the most serious Ebola epidemics in history and greatly threatened public health worldwide. The development of additional effective anti-Ebola therapeutic agents is therefore quite urgent. In this study, via high throughput screening of Food and Drug Administration-approved drugs, we identified that teicoplanin, a glycopeptide antibiotic, potently prevents the entry of Ebola envelope pseudotyped viruses into the cytoplasm. Furthermore, teicoplanin also has an inhibitory effect on transcription- and replication-competent virus-like particles, with an IC50 as low as 330 nm. Comparative analysis further demonstrated that teicoplanin is able to block the entry of Middle East respiratory syndrome (MERS) and severe acute respiratory syndrome (SARS) envelope pseudotyped viruses as well. Teicoplanin derivatives such as dalbavancin, oritavancin, and telavancin can also inhibit the entry of Ebola, MERS, and SARS viruses. Mechanistic studies showed that teicoplanin blocks Ebola virus entry by specifically inhibiting the activity of cathepsin L, opening a novel avenue for the development of additional glycopeptides as potential inhibitors of cathepsin L-dependent viruses. Notably, given that teicoplanin has routinely been used in the clinic with low toxicity, our work provides a promising prospect for the prophylaxis and treatment of Ebola, MERS, and SARS virus infection. PMID:26953343
Zhou, Nan; Pan, Ting; Zhang, Junsong; Li, Qianwen; Zhang, Xue; Bai, Chuan; Huang, Feng; Peng, Tao; Zhang, Jianhua; Liu, Chao; Tao, Liang; Zhang, Hui
2016-04-22
Ebola virus infection can cause severe hemorrhagic fever with a high mortality in humans. The outbreaks of Ebola viruses in 2014 represented the most serious Ebola epidemics in history and greatly threatened public health worldwide. The development of additional effective anti-Ebola therapeutic agents is therefore quite urgent. In this study, via high throughput screening of Food and Drug Administration-approved drugs, we identified that teicoplanin, a glycopeptide antibiotic, potently prevents the entry of Ebola envelope pseudotyped viruses into the cytoplasm. Furthermore, teicoplanin also has an inhibitory effect on transcription- and replication-competent virus-like particles, with an IC50 as low as 330 nm Comparative analysis further demonstrated that teicoplanin is able to block the entry of Middle East respiratory syndrome (MERS) and severe acute respiratory syndrome (SARS) envelope pseudotyped viruses as well. Teicoplanin derivatives such as dalbavancin, oritavancin, and telavancin can also inhibit the entry of Ebola, MERS, and SARS viruses. Mechanistic studies showed that teicoplanin blocks Ebola virus entry by specifically inhibiting the activity of cathepsin L, opening a novel avenue for the development of additional glycopeptides as potential inhibitors of cathepsin L-dependent viruses. Notably, given that teicoplanin has routinely been used in the clinic with low toxicity, our work provides a promising prospect for the prophylaxis and treatment of Ebola, MERS, and SARS virus infection. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.
Cui, Ning; Luo, Hesheng
2014-05-27
To explore the correlative factors and clinical characteristics of digestive system injury during the treatment of anticoagulant and (or) antiplatelet-agents. A total of 1 443 hospitalized patients on anticoagulant and (or) antiplatelet-agents from January 2010 to December 2013 at Renmin Hospital of Wuhan University were analyzed retrospectively. Their length of hospital stay was from 5 to 27 days. Most of them were elderly males (n = 880, 61.0%) with an average age of (62 ± 6) years. 1 138 patients (78.9%) were farmers, workers or someone without a specific occupation. During the treatment of anticoagulant/antiplatelet-agents, statistical difference existed (P = 0.01) between positively and negatively previous digestive disease groups for actively newly occurring digestive system injury (16.0% (41/256) vs 15.9% (189/1 187)). After the dosing of anticoagulant and (or) antiplatelet-agents, 57 (66.3%, 57/86) patients were complicated by hemorrhage of digestive tract, taking 62.9% (61/97) of all positive result patients for Helicobacter pylori test. Comparing preventive PPI group with no PPI group, there was no marked statistical differences (P = 2.67) for digestive system complication (including hemorrhage of digestive tract) while receiving anticoagulant and (or) antiplatelet-agents (13.9% (74/533) vs 17.1% (156/910)). During anticoagulant and/or antiplatelet-agent therapy, 185 patients (12.8%) were complicated by peptic ulcer or peptic ulcer with bleeding, 40 patients (2.8%) had erosive gastritis and 5 (0.3%) developed acute gastric mucosal lesions. And 42 of 76 patients complicated by hemorrhage of digestive tract underwent endoscopic hemostasis while 2 patients were operated. Ninety-seven patients (6.7%) died, including 61 (62.9%, 61/97) from hemorrhage of digestive tract. The remainder became cured, improved and discharged. Moreover, no significant statistical differences existed (P = 2.29) among three combination group (aspirin, clopidogrel, warfarin), two
Ma, Jingzhe; Ge, Jian; Prochaska, J. Xavier; Zhang, Shaohua; Ji, Tuo; Zhao, Yinan; Zhou, Hongyan; Lu, Honglin; Schneider, Donald P.
2018-03-01
We present the cold neutral content (H I and C I gas) of 13 quasar 2175 Å dust absorbers (2DAs) at z = 1.6-2.5 to investigate the correlation between the presence of the UV extinction bump with other physical characteristics. These 2DAs were initially selected from the Sloan Digital Sky Surveys I-III and followed up with the Keck-II telescope and the Multiple Mirror Telescope as detailed in our Paper I. We perform a correlation analysis between metallicity, redshift, depletion level, velocity width, and explore relationships between 2DAs and other absorption line systems. The 2DAs on average have higher metallicity, higher depletion levels, and larger velocity widths than Damped Lyman α absorbers (DLAs) or subDLAs. The correlation between [Zn/H] and [Fe/Zn] or [Zn/H] and logΔV90 can be used as alternative stellar mass estimators based on the well-established mass-metallicity relation. The estimated stellar masses of the 2DAs in this sample are in the range of ˜109 to ˜2 × 1011 M⊙ with a median value of ˜2 × 1010 M⊙. The relationship with other quasar absorption line systems can be described as (1) 2DAs are a subset of Mg II and Fe II absorbers, (2) 2DAs are preferentially metal-strong DLAs/subDLAs, (3) More importantly, all of the 2DAs show C I detections with logN(C I) > 14.0 cm-2, and (4) 2DAs can be used as molecular gas tracers. Their host galaxies are likely to be chemically enriched, evolved, massive (more massive than typical DLA/subDLA galaxies), and presumably star-forming galaxies.
Hankel Matrix Correlation Function-Based Subspace Identification Method for UAV Servo System
Directory of Open Access Journals (Sweden)
Minghong She
2018-01-01
Full Text Available For the identification problem of closed-loop subspace model, we propose a zero space projection method based on the estimation of correlation function to fill the block Hankel matrix of identification model by combining the linear algebra with geometry. By using the same projection of related data in time offset set and LQ decomposition, the multiplication operation of projection is achieved and dynamics estimation of the unknown equipment system model is obtained. Consequently, we have solved the problem of biased estimation caused when the open-loop subspace identification algorithm is applied to the closed-loop identification. A simulation example is given to show the effectiveness of the proposed approach. In final, the practicability of the identification algorithm is verified by hardware test of UAV servo system in real environment.
Johansson, Johannes D; Mireles, Miguel; Morales-Dalmau, Jordi; Farzam, Parisa; Martínez-Lozano, Mar; Casanovas, Oriol; Durduran, Turgut
2016-02-01
A scanning system for small animal imaging using non-contact, hybrid broadband diffuse optical spectroscopy (ncDOS) and diffuse correlation spectroscopy (ncDCS) is presented. The ncDOS uses a two-dimensional spectrophotometer retrieving broadband (610-900 nm) spectral information from up to fifty-seven source-detector distances between 2 and 5 mm. The ncDCS data is simultaneously acquired from four source-detector pairs. The sample is scanned in two dimensions while tracking variations in height. The system has been validated with liquid phantoms, demonstrated in vivo on a human fingertip during an arm cuff occlusion and on a group of mice with xenoimplanted renal cell carcinoma.
Mean first-passage time of an asymmetric bistable system driven by colour-correlated noise
Institute of Scientific and Technical Information of China (English)
Zhang Xiao-Yan; Xu Wei
2007-01-01
In this paper, the effect of every parameter (including p, q,r, λ,τ) on the mean first-passage time (MFPT) is investigated in an asymmetric bistable system driven by colour-correlated noise. The expression of MFPT has been obtained by applying the steepest-descent approximation. Numerical results show that (1) the intensity of multiplicative noise p and the intensity of additive noise q play different roles in the MFPT of the system, (2) suppression appears on the curve of the MFPT with small λ (e.g. λ＜ 0.5) but there is a peak on the curve of the MFPT when λ is big (e.g.λ＞ 0.5), and (3) with different values of r (e.g. r = 0.1, 0.5, 1.5), the effort of τ on the MFPT is diverse.
Quantum physics of light and matter photons, atoms, and strongly correlated systems
Salasnich, Luca
2017-01-01
This compact but exhaustive textbook, now in its significantly revised and expanded second edition, provides an essential introduction to the field quantization of light and matter with applications to atomic physics and strongly correlated systems. Following an initial review of the origins of special relativity and quantum mechanics, individual chapters are devoted to the second quantization of the electromagnetic field and the consequences of light field quantization for the description of electromagnetic transitions. The spin of the electron is then analyzed, with particular attention to its derivation from the Dirac equation. Subsequent topics include the effects of external electric and magnetic fields on the atomic spectra and the properties of systems composed of many interacting identical particles. The book also provides a detailed explanation of the second quantization of the non-relativistic matter field, i.e., the Schrödinger field, which offers a powerful tool for the investigation of many-body...
Energy Technology Data Exchange (ETDEWEB)
Shaginyan, V.R. [Petersburg Nuclear Physics Institute, RAS, Gatchina 188300 (Russian Federation); Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel)], E-mail: vrshag@thd.pnpi.spb.ru; Amusia, M.Ya. [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel); Popov, K.G. [Komi Science Center, Ural Division, RAS, Syktyvkar 167982 (Russian Federation)
2009-06-15
Basing on the density functional theory of fermion condensation, we analyze the non-Fermi liquid behavior of strongly correlated Fermi-systems such as heavy-fermion metals. When deriving equations for the effective mass of quasiparticles, we consider solids with a lattice and homogeneous systems. We show that the low-temperature thermodynamic and transport properties are formed by quasiparticles, while the dependence of the effective mass on temperature, number density, magnetic fields, etc., gives rise to the non-Fermi liquid behavior. Our theoretical study of the heat capacity, magnetization, energy scales, the longitudinal magnetoresistance and magnetic entropy are in good agreement with the remarkable recent facts collected on the heavy-fermion metal YbRh{sub 2}Si{sub 2}.
International Nuclear Information System (INIS)
Shaginyan, V.R.; Amusia, M.Ya.; Popov, K.G.
2009-01-01
Basing on the density functional theory of fermion condensation, we analyze the non-Fermi liquid behavior of strongly correlated Fermi-systems such as heavy-fermion metals. When deriving equations for the effective mass of quasiparticles, we consider solids with a lattice and homogeneous systems. We show that the low-temperature thermodynamic and transport properties are formed by quasiparticles, while the dependence of the effective mass on temperature, number density, magnetic fields, etc., gives rise to the non-Fermi liquid behavior. Our theoretical study of the heat capacity, magnetization, energy scales, the longitudinal magnetoresistance and magnetic entropy are in good agreement with the remarkable recent facts collected on the heavy-fermion metal YbRh 2 Si 2 .
Foundations for a time reliability correlation system to quantify human reliability
International Nuclear Information System (INIS)
Dougherty, E.M. Jr.; Fragola, J.R.
1988-01-01
Time reliability correlations (TRCs) have been used in human reliability analysis (HRA) in conjunction with probabilistic risk assessment (PRA) to quantify post-initiator human failure events. The first TRCs were judgmental but recent data taken from simulators have provided evidence for development of a system of TRCs. This system has the equational form: t = tau R X tau U , where the first factor is the lognormally distributed random variable of successful response time, derived from the simulator data, and the second factor is a unitary lognormal random variable to account for uncertainty in the model. The first random variable is further factored into a median response time and a factor to account for the dominant type of behavior assumed to be involved in the response and a second factor to account for other influences on the reliability of the response
Directory of Open Access Journals (Sweden)
Johnson William D
2010-07-01
Full Text Available Abstract Background Obesity is a pro-inflammatory state frequently associated with widespread metabolic alterations that include insulin resistance and deregulation of blood pressure (BP. This cascade of events in some measure explains the susceptibility of obese adults for co-morbid conditions like diabetes mellitus and hypertension. Hypothesis We hypothesized that an elevated systemic proinflammatory burden correlates with dysglycemia and deregulated blood pressure. Methods We analyzed the screening anthropometric and laboratory measures from healthy disease free obese adults (n = 35; women (W 27, men (M 8 in a weight loss study. Results Healthy obese normoglycemic (fasting serum glucose: FSG Conclusions In otherwise healthy disease free obese adults, a higher degree of systemic inflammation is associated with prediabetes and prehypertension.
Riccieri, Valeria; Spadaro, Antonio; Fuksa, Leos; Firuzi, Omidreza; Saso, Luciano; Valesini, Guido
2008-02-01
Oxidative stress is suggested to be involved in the pathogenesis of systemic sclerosis (SSc). The aim of the present study was to clarify such a hypothesis by determination of four different plasmatic parameters of oxidative stress, and to define its role in the microvascular damage, assessed by nailfold capillaroscopy (NC). Plasma samples of 18 patients with SSc were analyzed. The biomarkers measured were: total antioxidant capacity, hydroperoxides (ROOHs), and sulfhydryl (SH) and carbonyl (CO) groups. Each patient had a detailed clinical assessment and underwent an NC. The results showed significantly increased ROOHs in SSc patients compared to control group (5.02 +/- 0.24 vs 3.28 +/- 0.19 micromol/l; p capillaroscopy semiquantitative rating scale score (p < 0.05) and with the rating system for avascular areas (p < 0.03). The levels of CO groups inversely correlated with modified Rodnan's skin score (p < 0.039) and were lower in patients with pulmonary fibrosis (p < 0.045), while the levels of SH groups were lower in those presenting gastrointestinal involvement (p < 0.029). The obtained data indicate augmented free radical-mediated injury in SSc and also show correlations among oxidative abnormalities, some clinical findings, and signs of a more severe microvascular involvement. These results give more evidence to the connection between oxidative impairment and SSc.
Influence of spin correlations in the transport properties of a double quantum dot system
Costa Ribeiro, Laercio; Hamad, Ignacio; Chiappe, Guillermo; Victoriano Anda, Enrique
2013-03-01
In this work we study the influence of spin correlations in the transport properties of a system consisting of two quantum dots (QDs) with high Coulomb interaction U which are interconnected through a chain of N non-interacting sites and individually coupled to two metallic leads. Using both the finite U slave boson mean field approach (FUSBMFA) and the Logarithmic-discretization-embedded-cluster approximation (LDECA) we studied the system in different regions of the parameter space for which we calculate many physical quantities, namely local density of states, conductance, total spin, spin correlations, in addition to the renormalization parameters associated with the FUSBMFA. The results reveled a very rich physical scenario which is manifested by at least two different Kondo regimes, the well-known spin s = 1/2 and some other type of Kondo effect which appears as a result of the coupling between the QDs and the non-interacting central sites. We also consider the possibility of accessing some kind of Kondo box effect due to the discrete nature of the central chain and study how this regime is affected by the magnetic interaction between the local spins of the QD's and by the interaction between these spins and the spins of the conduction electros in the leads.
Directory of Open Access Journals (Sweden)
Zhang Hua-Li
2011-01-01
Full Text Available OBJECTIVE: To explore the characteristics of seasonal distribution of active systemic lupus erythematosus (SLE and the influences of meteorological factors including temperature and humidity on active systemic lupus erythematosus. METHODS: The characteristics of seasonal distribution of active SLE and its correlation with meteorological factors were retrospectively analyzed in 640 patients living in the city of Zhanjiang, China and had active SLE between January 1997 and December 2006. RESULTS: In winter, when there are weaker ultraviolet (UV rays, the ratio of patients with active SLE to total inpatients was 3.89 %o, which is significantly higher than in other seasons with stronger UV rays, including 2.17 %o in spring, 1.87 0 in summer and 2.12 0 in autumn. The number of patients with active SLE had significant negative correlation with mean temperature and was not significantly related to mean humidity. CONCLUSION: Active SLE has the characteristics of seasonal distribution and is associated with temperature. The mechanism remains to be further studied.
Irreducible Greens' Functions method in the theory of highly correlated systems
International Nuclear Information System (INIS)
Kuzemsky, A.L.
1994-09-01
The self-consistent theory of the correlation effects in Highly Correlated Systems (HCS) is presented. The novel Irreducible Green's Function (IGF) method is discussed in detail for the Hubbard model and random Hubbard model. The interpolation solution for the quasiparticle spectrum, which is valid for both the atomic and band limit is obtained. The (IGF) method permits to calculate the quasiparticle spectra of many-particle systems with the complicated spectra and strong interaction in a very natural and compact way. The essence of the method deeply related to the notion of the Generalized Mean Fields (GMF), which determine the elastic scattering corrections. The inelastic scattering corrections leads to the damping of the quasiparticles and are the main topic of the present consideration. The calculation of the damping has been done in a self-consistent way for both limits. For the random Hubbard model the weak coupling case has been considered and the self-energy operator has been calculated using the combination of the IGF method and Coherent Potential Approximation (CPA). The other applications of the method to the s-f model, Anderson model, Heisenberg antiferromagnet, electron-phonon interaction models and quasiparticle tunneling are discussed briefly. (author). 79 refs
New developments in the theoretical treatment of low dimensional strongly correlated systems.
James, Andrew J A; Konik, Robert M; Lecheminant, Philippe; Robinson, Neil; Tsvelik, Alexei M
2017-10-09
We review two important non-perturbative approaches for extracting the physics of low- dimensional strongly correlated quantum systems. Firstly, we start by providing a comprehensive review of non-Abelian bosonization. This includes an introduction to the basic elements of confor- mal field theory as applied to systems with a current algebra, and we orient the reader by presenting a number of applications of non-Abelian bosonization to models with large symmetries. We then tie this technique into recent advances in the ability of cold atomic systems to realize complex symme- tries. Secondly, we discuss truncated spectrum methods for the numerical study of systems in one and two dimensions. For one-dimensional systems we provide the reader with considerable insight into the methodology by reviewing canonical applications of the technique to the Ising model (and its variants) and the sine-Gordon model. Following this we review recent work on the development of renormalization groups, both numerical and analytical, that alleviate the effects of truncating the spectrum. Using these technologies, we consider a number of applications to one-dimensional systems: properties of carbon nanotubes, quenches in the Lieb-Liniger model, 1+1D quantum chro- modynamics, as well as Landau-Ginzburg theories. In the final part we move our attention to consider truncated spectrum methods applied to two-dimensional systems. This involves combining truncated spectrum methods with matrix product state algorithms. We describe applications of this method to two-dimensional systems of free fermions and the quantum Ising model, including their non-equilibrium dynamics. © 2017 IOP Publishing Ltd.
Pathogenic Cascades in Lysosomal Disease – Why so Complex?
Walkley, Steven U.
2009-01-01
Lysosomal disease represents a large group of more than 50 clinically recognized conditions resulting from inborn errors of metabolism affecting the organelle known as the lysosome.The lysosome is an integral part of the larger endosomal/lysosomal system, and is closely allied with the ubiquitin-proteosomal and autophagosomal systems, which together comprise essential cell machinery for substrate degradation and recycling, homeostatic control, as well as signaling. More than two-thirds of lys...
Photon correlations in a two-site nonlinear cavity system under coherent drive and dissipation
International Nuclear Information System (INIS)
Ferretti, Sara; Andreani, Lucio Claudio; Tuereci, Hakan E.; Gerace, Dario
2010-01-01
We calculate the normalized second-order correlation function for a system of two tunnel-coupled photonic resonators, each one exhibiting a single-photon nonlinearity of the Kerr type. We employ a full quantum formulation: The master equation for the model, which takes into account both a coherent continuous drive and radiative as well as nonradiative dissipation channels, is solved analytically in steady state through a perturbative approach, and the results are compared to exact numerical simulations. The degree of second-order coherence displays values between 0 and 1, and divides the diagram identified by the two energy scales of the system - the tunneling and the nonlinear Kerr interaction - into two distinct regions separated by a crossover. When the tunneling term dominates over the nonlinear one, the system state is delocalized over both cavities, and the emitted light is coherent. In the opposite limit, photon blockade sets in, and the system shows an insulatorlike state with photons locked on each cavity, identified by antibunching of emitted light.
Bărbulescu, Andreea Lili; Vreju, Ananu Florentin; Bugă, Ana Maria; Sandu, Raluca Elena; Criveanu, Cristina; Tudoraşcu, Diana Rodica; Gheonea, Ioana Andreea; Ciurea, Paulina Lucia
2015-01-01
Our study aimed to quantify serum VEGF (vascular endothelial growth factor) and its inter-relation with the severity of microvascular damage, assessed by nailfold capillaroscopy (NC), and to establish the possible relationship with disease activity score. We included 18 patients, diagnosed with systemic lupus erythematosus (SLE) and 17 gender and age-matched control subjects. For determining serum VEGF, we used a Human VEGF Assay kit-IBL. NC was performed, according to the standard method, using a video-capillaroscope Videocap 3.0, DS Medica, by the same examiner, blinded to clinical and laboratory data. Serum VEGF registered a mean value of 68.99±71.06 pg/mL for SLE patients and 31.84±11.74 pg/mL for controls, differences statistically significant; depending on disease activity, we found a mean value of 60.11±57.74 pg/mL, for patients with moderate disease activity vs. 30.96±11.51 pg/mL for the ones with a low activity (p=0.014). We found a moderately positive correlation, statistically significant (p=0.015), between serum level of VEGF and Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). Performing NC, we found changes in 88.88% of the patients; the most frequent were increased tortuosity, dilated capillaries, an increased length and a prominent subpapillary plexus. The presence of nailfold capillaroscopy changes and serum level of VEGF, correlated moderately, positive. Since serum levels of VEGF are higher in SLE patients, compared to controls, significantly different according to disease activity degree, and directly inter-related to abnormal NC patterns and a more active disease, we can include these accessible parameters in the routine evaluation, in order to better quantify the systemic damage, individualize the treatment, improve the outcome and life quality for these patients.
International Nuclear Information System (INIS)
Grasso, M.
2009-10-01
This document is a summary of the author's research activities whose common topic is the N-body problem. The first chapter introduces the N-body issue through models based on the mean-field theory and on the Hartree-Fock-Bogoliubov equations. The second chapter presents the understanding of exotic nuclei features within the mean-field approach. Exotic phenomena like nuclear bubble structure, pairing correlations and pairing violations, giant neutron halos, non-standard terms in the Skyrme interactions are reviewed. The chapter 3 is dedicated to some extensions of the RPA (random phase approximation). For instance the computation of the shell structure far from the stability valley requires a more accurate assessment of the energy of the individual states through the introduction of a particle-vibration coupling. Different RPA extensions are described: first the self-consistent extension enlarged beyond particle-hole configurations, then the boson-mapping-based extension in a 3-level Lipkin model and also the second random-phase approximation. The chapter 4 gathers some studies concerning ultra-cold gases of trapped atoms. These systems are the only structures that allow the study of the correlations associated to superfluidity in terms of interaction intensity, temperature or system size. The mean-field approach is adequate for these studies. The last chapter draws a perspective for the mean-field-based models, their limits are assessed and ways of improvement are proposed. (A.C.)
Sway Area and Velocity Correlated With MobileMat Balance Error Scoring System (BESS) Scores.
Caccese, Jaclyn B; Buckley, Thomas A; Kaminski, Thomas W
2016-08-01
The Balance Error Scoring System (BESS) is often used for sport-related concussion balance assessment. However, moderate intratester and intertester reliability may cause low initial sensitivity, suggesting that a more objective balance assessment method is needed. The MobileMat BESS was designed for objective BESS scoring, but the outcome measures must be validated with reliable balance measures. Thus, the purpose of this investigation was to compare MobileMat BESS scores to linear and nonlinear measures of balance. Eighty-eight healthy collegiate student-athletes (age: 20.0 ± 1.4 y, height: 177.7 ± 10.7 cm, mass: 74.8 ± 13.7 kg) completed the MobileMat BESS. MobileMat BESS scores were compared with 95% area, sway velocity, approximate entropy, and sample entropy. MobileMat BESS scores were significantly correlated with 95% area for single-leg (r = .332) and tandem firm (r = .474), and double-leg foam (r = .660); and with sway velocity for single-leg (r = .406) and tandem firm (r = .601), and double-leg (r = .575) and single-leg foam (r = .434). MobileMat BESS scores were not correlated with approximate or sample entropy. MobileMat BESS scores were low to moderately correlated with linear measures, suggesting the ability to identify changes in the center of mass-center of pressure relationship, but not higher-order processing associated with nonlinear measures. These results suggest that the MobileMat BESS may be a clinically-useful tool that provides objective linear balance measures.
Golemati, Christina V; Moutsopoulos, Haralampos M; Vlachoyiannopoulos, Panayiotis G
2013-01-01
The aim of this paper is to assess the psychological characteristics of personality, depression, anxiety, social support and coping strategies of systemic sclerosis (SSc) patients, their inter-correlations and their association with clinical symptoms. Patients with SSc (n=85) were interviewed and compared to rheumatoid arthritis (RA) patients (n=120) and healthy controls (HCs [n=125]). Psychological characteristics were assessed by the following psychometric scales: centre of epidemiological studies of depression (CES-D), hospital anxiety and depression scale (HAD), Eysenck personality questionnaire (EPQ), short form of social support (SSq), life experiences survey (LES) and ways of coping (WoC). Clinical data were collected at the same time of the interview. Both control groups were matched to SSc patients in terms of gender, age and educational status. Data were analysed with SPSS software. Compared to control groups, SSc patients expressed more symptoms of depression and anxiety, showed less extraversion and reported more negative life events. They coped less often with positive reappraisal, problem solving, seeking of support and assertiveness, while they sought more often divine help, and they expressed wishing and denial. Inactive disease was associated with a lower probability of reporting depressive symptoms and negative life events and with a higher probability of positively reevaluating a problem. Lung dysfunction, skin involvement, esophageal problems and oral aperture correlated with psychological features. Complications in psychological well-being characterise patients with SSc. This finding, as well as that of psychological characteristics correlating with organic factors, is an indication for designing supportive psycho-educational programmes as complementary therapies.
Lyapunov Exponent and Out-of-Time-Ordered Correlator's Growth Rate in a Chaotic System.
Rozenbaum, Efim B; Ganeshan, Sriram; Galitski, Victor
2017-02-24
It was proposed recently that the out-of-time-ordered four-point correlator (OTOC) may serve as a useful characteristic of quantum-chaotic behavior, because, in the semiclassical limit ℏ→0, its rate of exponential growth resembles the classical Lyapunov exponent. Here, we calculate the four-point correlator C(t) for the classical and quantum kicked rotor-a textbook driven chaotic system-and compare its growth rate at initial times with the standard definition of the classical Lyapunov exponent. Using both quantum and classical arguments, we show that the OTOC's growth rate and the Lyapunov exponent are, in general, distinct quantities, corresponding to the logarithm of the phase-space averaged divergence rate of classical trajectories and to the phase-space average of the logarithm, respectively. The difference appears to be more pronounced in the regime of low kicking strength K, where no classical chaos exists globally. In this case, the Lyapunov exponent quickly decreases as K→0, while the OTOC's growth rate may decrease much slower, showing a higher sensitivity to small chaotic islands in the phase space. We also show that the quantum correlator as a function of time exhibits a clear singularity at the Ehrenfest time t_{E}: transitioning from a time-independent value of t^{-1}lnC(t) at ttime at t>t_{E}. We note that the underlying physics here is the same as in the theory of weak (dynamical) localization [Aleiner and Larkin, Phys. Rev. B 54, 14423 (1996)PRBMDO0163-182910.1103/PhysRevB.54.14423; Tian, Kamenev, and Larkin, Phys. Rev. Lett. 93, 124101 (2004)PRLTAO0031-900710.1103/PhysRevLett.93.124101] and is due to a delay in the onset of quantum interference effects, which occur sharply at a time of the order of the Ehrenfest time.
Many-particle correlations in quasi-two-dimensional electron-hole systems
International Nuclear Information System (INIS)
Nikolaev, Valentin
2002-01-01
This thesis reports a theoretical investigation of many-particle correlation effects in semiconductor heterostructures containing quantum wells. Particular attention is paid towards quasi-particle pair correlations. Using the Green's function technique and the ladder approximation as a basis, the generalized mass action law, which describes the redistribution of particles between correlated and uncorrelated states in quasi-two-dimensional systems for different temperatures and total densities, is derived. The expression is valid beyond the low-density limit, which allows us to investigate the transition of the system from a dilute exciton gas to a dense electron-hole plasma. A generalized Levinson theorem, which takes k-space filling into account, is formulated. Screening in quasi-two-dimensional systems is analyzed rigorously. Firstly, the qualitatively new mechanism of static local screening by indirect excitons is studied using the simple Thomas-Fermi approximation. Then, a detailed many-body description suitable for a proper account of dynamic screening by a quasi-2D electron-hole plasma, and consistent with the previously derived mass action law, is provided. The generalized Lindhard approximation and excitonic plasmon-pole approximations are also derived. The theory is applied to single and double quantum wells. A self-consistent procedure is developed for numerical investigation of the ionization degree of an electron-hole plasma at different values of temperature/exciton Rydberg ratios. This procedure accounts for screening, k-space filling (exciton bleaching), and the formation of excitons. An abrupt jump in the value of the ionization degree that happens with an increase of the carrier density or temperature (Mott transition) is found in a certain density-temperature region. It has been found that the critical density of the Mott transition for indirect excitons may be much smaller than that for direct excitons. A suggestion has been made that some of the
Management system - correlation study between new IAEA standards and the market standards
Energy Technology Data Exchange (ETDEWEB)
Oliveira, Dirceu Paulo de [Centro Tecnologico da Marinha em Sao Paulo (CTMSP), Ipero, SP (Brazil)], e-mail: dirceupo@hotmail.com; Zouain, Desiree Moraes [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)], e-mail: dmzouain@ipen.br
2009-07-01
In order to answer the growing concern of society with respect of the aspects that affect the quality of life, international and national regulatory bodies have developed standards that enable organizations to establish management systems for quality, environment and sustainable development, health, safety and social responsibility, among other functions. Within this context it is necessary to structure an integrated management system that promotes interests compatibility of several distinct and complementary functions involved. Considering this vision of the management system integration, the International Atomic Energy Agency (IAEA) decided to review the structure of safety standards on Quality Assurance - code and guides 50-C/SGQ1/ 14:1996, publishing, in 2006, IAEA GS-R-3 and IAEA GS-G-3.1 standards, enlarging the management approach of the previous standards, including the possibility of integrating the functions foremost mentioned. This paper presents the results about a correlation study between IAEA management system standards - IAEA GS-R-3: 2006, IAEA GS-G-3.1: 2006 and IAEA DS349 rev. 2007, this latter still a draft standard, with those market management system standards on quality - ISO 9001:2008, environmental - ISO 14001:2004, and occupational health and safety - BS OHSAS 18001:2007, identifying gaps, redundancies and complementarities among their requirements and guidances. The purpose of the study is to provide subsidies that could contribute to the structuring of a management system to nuclear facilities that satisfies, in an integrated manner, the common and complementary requirements and guidances of IAEA and market standards. (author)
Management system - correlation study between new IAEA standards and the market standards
International Nuclear Information System (INIS)
Oliveira, Dirceu Paulo de; Zouain, Desiree Moraes
2009-01-01
In order to answer the growing concern of society with respect of the aspects that affect the quality of life, international and national regulatory bodies have developed standards that enable organizations to establish management systems for quality, environment and sustainable development, health, safety and social responsibility, among other functions. Within this context it is necessary to structure an integrated management system that promotes interests compatibility of several distinct and complementary functions involved. Considering this vision of the management system integration, the International Atomic Energy Agency (IAEA) decided to review the structure of safety standards on Quality Assurance - code and guides 50-C/SGQ1/ 14:1996, publishing, in 2006, IAEA GS-R-3 and IAEA GS-G-3.1 standards, enlarging the management approach of the previous standards, including the possibility of integrating the functions foremost mentioned. This paper presents the results about a correlation study between IAEA management system standards - IAEA GS-R-3: 2006, IAEA GS-G-3.1: 2006 and IAEA DS349 rev. 2007, this latter still a draft standard, with those market management system standards on quality - ISO 9001:2008, environmental - ISO 14001:2004, and occupational health and safety - BS OHSAS 18001:2007, identifying gaps, redundancies and complementarities among their requirements and guidances. The purpose of the study is to provide subsidies that could contribute to the structuring of a management system to nuclear facilities that satisfies, in an integrated manner, the common and complementary requirements and guidances of IAEA and market standards. (author)
International Nuclear Information System (INIS)
Elyutin, P V; Rubtsov, A N
2008-01-01
The energy evolution of a quantum chaotic system under the perturbation that harmonically depends on time is studied for the case of large perturbation, in which the rate of transition calculated from the Fermi golden rule (FGR) is about or exceeds the frequency of perturbation. For this case, the models of the Hamiltonian with random non-correlated matrix elements demonstrate that the energy evolution retains its diffusive character, but the rate of diffusion increases slower than the square of the magnitude of perturbation, thus destroying the quantum-classical correspondence for the energy diffusion and the energy absorption in the classical limit ℎ → 0. The numerical calculation carried out for a model built from the first principles (the quantum analog of the Pullen-Edmonds oscillator) demonstrates that the evolving energy distribution, apart from the diffusive component, contains a ballistic one with the energy dispersion that is proportional to the square of time. This component originates from the chains of matrix elements with correlated signs and vanishes if the signs of matrix elements are randomized. The presence of the ballistic component formally extends the applicability of the FGR to the non-perturbative domain and restores the quantum-classical correspondence
Spatial correlation characterization of a uniform circular array in 3D MIMO systems
Nadeem, Qurrat-Ul-Ain
2016-08-11
In this paper, we consider a uniform circular array (UCA) of directional antennas at the base station (BS) and the mobile station (MS) and derive an exact closed-form expression for the spatial correlation present in the 3D multiple-input multiple-output (MIMO) channel constituted by these arrays. The underlying method leverages the mathematical convenience of the spherical harmonic expansion (SHE) of plane waves and the trigonometric expansion of Legendre and associated Legendre polynomials. In contrast to the existing results, this generalized closed-form expression is independent of the form of the underlying angular distributions and antenna patterns. Moreover, the incorporation of the elevation dimension into the antenna pattern and channel model renders the proposed expression extremely useful for the performance evaluation of 3D MIMO systems in the future. Verification is achieved with the help of simulation results, which highlight the dependence of the spatial correlation on channel and array parameters. An interesting interplay between the mean angle of departure (AoD), angular spread and the positioning of antennas in the array is demonstrated. © 2016 IEEE.
Spatial correlation characterization of a uniform circular array in 3D MIMO systems
Nadeem, Qurrat-Ul-Ain; Kammoun, Abla; Debbah, Merouane; Alouini, Mohamed-Slim
2016-01-01
In this paper, we consider a uniform circular array (UCA) of directional antennas at the base station (BS) and the mobile station (MS) and derive an exact closed-form expression for the spatial correlation present in the 3D multiple-input multiple-output (MIMO) channel constituted by these arrays. The underlying method leverages the mathematical convenience of the spherical harmonic expansion (SHE) of plane waves and the trigonometric expansion of Legendre and associated Legendre polynomials. In contrast to the existing results, this generalized closed-form expression is independent of the form of the underlying angular distributions and antenna patterns. Moreover, the incorporation of the elevation dimension into the antenna pattern and channel model renders the proposed expression extremely useful for the performance evaluation of 3D MIMO systems in the future. Verification is achieved with the help of simulation results, which highlight the dependence of the spatial correlation on channel and array parameters. An interesting interplay between the mean angle of departure (AoD), angular spread and the positioning of antennas in the array is demonstrated. © 2016 IEEE.
Chang, Yao-Chung; Lai, Chin-Feng; Chuang, Chi-Cheng; Hou, Cheng-Yu
2018-04-01
With the progress of science and technology, more and more machines are adpot to help human life better and more convenient. When the machines have been used for a longer period of time so that the machine components are getting old, the amount of power comsumption will increase and easily cause the machine to overheat. This also causes a waste of invisible resources. If the Internet of Everything (IoE) technologies are able to be applied into the enterprise information systems for monitoring the machines use time, it can not only make energy can be effectively used, but aslo create a safer living environment. To solve the above problem, the correlation predict model is established to collect the data of power consumption converted into power eigenvalues. This study takes the power eigenvalue as the independent variable and use time as the dependent variable in order to establish the decline curve. Ultimately, the scoring and estimation modules are employed to seek the best power eigenvalue as the independent variable. To predict use time, the correlation is discussed between the use time and the decline curve to improve the entire behavioural analysis of the facilitate recognition of the use time of machines.
Multiple-scattering formalism for correlated systems: A KKR-DMFT approach
International Nuclear Information System (INIS)
Minar, J.; Perlov, A.; Ebert, H.; Chioncel, L.; Katsnelson, M. I.; Lichtenstein, A.I.
2005-01-01
We present a charge and self-energy self-consistent computational scheme for correlated systems based on the Korringa-Kohn-Rostoker (KKR) multiple scattering theory with the many-body effects described by the means of dynamical mean field theory (DMFT). The corresponding local multiorbital and energy dependent self-energy is included into the set of radial differential equations for the single-site wave functions. The KKR Green's function is written in terms of the multiple scattering path operator, the later one being evaluated using the single-site solution for the t-matrix that in turn is determined by the wave functions. An appealing feature of this approach is that it allows to consider local quantum and disorder fluctuations on the same footing. Within the coherent potential approximation (CPA) the correlated atoms are placed into a combined effective medium determined by the DMFT self-consistency condition. Results of corresponding calculations for pure Fe, Ni, and Fe x Ni 1-x alloys are presented
Preschool acuity of the approximate number system correlates with school math ability.
Libertus, Melissa E; Feigenson, Lisa; Halberda, Justin
2011-11-01
Previous research shows a correlation between individual differences in people's school math abilities and the accuracy with which they rapidly and nonverbally approximate how many items are in a scene. This finding is surprising because the Approximate Number System (ANS) underlying numerical estimation is shared with infants and with non-human animals who never acquire formal mathematics. However, it remains unclear whether the link between individual differences in math ability and the ANS depends on formal mathematics instruction. Earlier studies demonstrating this link tested participants only after they had received many years of mathematics education, or assessed participants' ANS acuity using tasks that required additional symbolic or arithmetic processing similar to that required in standardized math tests. To ask whether the ANS and math ability are linked early in life, we measured the ANS acuity of 200 3- to 5-year-old children using a task that did not also require symbol use or arithmetic calculation. We also measured children's math ability and vocabulary size prior to the onset of formal math instruction. We found that children's ANS acuity correlated with their math ability, even when age and verbal skills were controlled for. These findings provide evidence for a relationship between the primitive sense of number and math ability starting early in life. 2011 Blackwell Publishing Ltd.
Measuring time-of-flight in an ultrasonic LPS system using generalized cross-correlation.
Villladangos, José Manuel; Ureña, Jesús; García, Juan Jesús; Mazo, Manuel; Hernández, Alvaro; Jiménez, Ana; Ruíz, Daniel; De Marziani, Carlos
2011-01-01
In this article, a time-of-flight detection technique in the frequency domain is described for an ultrasonic local positioning system (LPS) based on encoded beacons. Beacon transmissions have been synchronized and become simultaneous by means of the DS-CDMA (direct-sequence code Division multiple access) technique. Every beacon has been associated to a 255-bit Kasami code. The detection of signal arrival instant at the receiver, from which the distance to each beacon can be obtained, is based on the application of the generalized cross-correlation (GCC), by using the cross-spectral density between the received signal and the sequence to be detected. Prior filtering to enhance the frequency components around the carrier frequency (40 kHz) has improved estimations when obtaining the correlation function maximum, which implies an improvement in distance measurement precision. Positioning has been achieved by using hyperbolic trilateration, based on the time differences of arrival (TDOA) between a reference beacon and the others.
Bond, Tom; Templeton, Michael R; Mokhtar Kamal, Nurul Hana; Graham, Nigel; Kanda, Rakesh
2015-11-15
Despite the recent focus on nitrogenous disinfection byproducts in drinking water, there is limited occurrence data available for many species. This paper analyses the occurrence of seven haloacetonitriles, three haloacetamides, eight halonitromethanes and cyanogen chloride in 20 English drinking water supply systems. It is the first survey of its type to compare bromine substitution factors (BSFs) between the haloacetamides and haloacetonitriles. Concentrations of the dihalogenated haloacetonitriles and haloacetamides were well correlated. Although median concentrations of these two groups were lower in chloraminated than chlorinated surface waters, median BSFs for both in chloraminated samples were approximately double those in chlorinated samples, which is significant because of the higher reported toxicity of the brominated species. Furthermore, median BSFs were moderately higher for the dihalogenated haloacetamides than for the haloacetonitriles. This indicates that, while the dihalogenated haloacetamides were primarily generated from hydrolysis of the corresponding haloacetonitriles, secondary formation pathways also contributed. Median halonitromethane concentrations were remarkably unchanging for the different types of disinfectants and source waters: 0.1 μg · mgTOC(-1) in all cases. Cyanogen chloride only occurred in a limited number of samples, yet when present its concentrations were higher than the other N-DBPs. Concentrations of cyanogen chloride and the sum of the halonitromethanes were not correlated with any other DBPs. Copyright © 2015 Elsevier Ltd. All rights reserved.
Sun, Jianwei; Perdew, John P.; Yang, Zenghui; Peng, Haowei
2016-05-01
The uniform electron gas and the hydrogen atom play fundamental roles in condensed matter physics and quantum chemistry. The former has an infinite number of electrons uniformly distributed over the neutralizing positively charged background, and the latter only one electron bound to the proton. The uniform electron gas was used to derive the local spin density approximation to the exchange-correlation functional that undergirds the development of the Kohn-Sham density functional theory. We show here that the ground-state exchange-correlation energies of the hydrogen atom and many other 1- and 2-electron systems are modeled surprisingly well by a different local spin density approximation (LSDA0). LSDA0 is constructed to satisfy exact constraints but agrees surprisingly well with the exact results for a uniform two-electron density in a finite, curved three-dimensional space. We also apply LSDA0 to excited or noded 1-electron densities, where it works less well. Furthermore, we show that the localization of the exact exchange hole for a 1- or 2-electron ground state can be measured by the ratio of the exact exchange energy to its optimal lower bound.
Bias of damped Lyman-α systems from their cross-correlation with CMB lensing
Alonso, D.; Colosimo, J.; Font-Ribera, A.; Slosar, A.
2018-04-01
We cross-correlate the positions of damped Lyman-α systems (DLAs) and their parent quasar catalog with a convergence map derived from the Planck cosmic microwave background (CMB) temperature data. We make consistent measurements of the lensing signal of both samples in both Fourier and configuration space. By interpreting the excess signal present in the DLA catalog with respect to the parent quasar catalog as caused by the large scale structure traced by DLAs, we are able to infer the bias of these objects: bDLA=2.6±0.9. These results are consistent with previous measurements made in cross-correlation with the Lyman-α forest, although the current noise in the lensing data and the low number density of DLAs limits the constraining power of this measurement. We discuss the robustness of the analysis with respect to a number different systematic effects and forecast prospects of carrying out this measurement with data from future experiments.
Measurement system of correlation functions of microwave single photon source in real time
Korenkov, A.; Dmitriev, A.; Astafiev, O.
2018-02-01
Several quantum setups, such as quantum key distribution networks[1] and quantum simulators (e.g. boson sampling), by their design rely on single photon sources (SPSs). These quantum setups were demonstrated to operate in optical frequency domain. However, following the steady advances in circuit quantum electrodynamics, a proposal has been made recently[2] to demonstrate boson sampling with microwave photons. This in turn requires the development of reliable microwave SPS. It's one of the most important characteristics are the first-order and the second-order correlation functions g1 and g2. The measurement technique of g1 and g2 is significantly different from that in the optical domain [3],[4] because of the current unavailability of microwave single-photon detectors. In particular, due to high levels of noise present in the system a substantial amount of statistics in needed to be acquired. This work presents a platform for measurement of g1 and g2 that processes the incoming data in real time, maximizing the efficiency of data acquisition. The use of field-programmable gate array (FPGA) electronics, common in similar experiments[3] but complex in programming, is avoided; instead, the calculations are performed on a standard desktop computer. The platform is used to perform the measurements of the first-order and the second-order correlation functions of the microwave SPS.
Energy Technology Data Exchange (ETDEWEB)
Sun, Jianwei; Yang, Zenghui; Peng, Haowei [Department of Physics, Temple University, Philadelphia, Pennsylvania 19122 (United States); Perdew, John P. [Department of Physics, Temple University, Philadelphia, Pennsylvania 19122 (United States); Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122 (United States)
2016-05-21
The uniform electron gas and the hydrogen atom play fundamental roles in condensed matter physics and quantum chemistry. The former has an infinite number of electrons uniformly distributed over the neutralizing positively charged background, and the latter only one electron bound to the proton. The uniform electron gas was used to derive the local spin density approximation to the exchange-correlation functional that undergirds the development of the Kohn-Sham density functional theory. We show here that the ground-state exchange-correlation energies of the hydrogen atom and many other 1- and 2-electron systems are modeled surprisingly well by a different local spin density approximation (LSDA0). LSDA0 is constructed to satisfy exact constraints but agrees surprisingly well with the exact results for a uniform two-electron density in a finite, curved three-dimensional space. We also apply LSDA0 to excited or noded 1-electron densities, where it works less well. Furthermore, we show that the localization of the exact exchange hole for a 1- or 2-electron ground state can be measured by the ratio of the exact exchange energy to its optimal lower bound.
International Nuclear Information System (INIS)
Sun, Jianwei; Yang, Zenghui; Peng, Haowei; Perdew, John P.
2016-01-01
The uniform electron gas and the hydrogen atom play fundamental roles in condensed matter physics and quantum chemistry. The former has an infinite number of electrons uniformly distributed over the neutralizing positively charged background, and the latter only one electron bound to the proton. The uniform electron gas was used to derive the local spin density approximation to the exchange-correlation functional that undergirds the development of the Kohn-Sham density functional theory. We show here that the ground-state exchange-correlation energies of the hydrogen atom and many other 1- and 2-electron systems are modeled surprisingly well by a different local spin density approximation (LSDA0). LSDA0 is constructed to satisfy exact constraints but agrees surprisingly well with the exact results for a uniform two-electron density in a finite, curved three-dimensional space. We also apply LSDA0 to excited or noded 1-electron densities, where it works less well. Furthermore, we show that the localization of the exact exchange hole for a 1- or 2-electron ground state can be measured by the ratio of the exact exchange energy to its optimal lower bound.
Czech Academy of Sciences Publication Activity Database
Peřinová, V.; Lukš, A.; Křepelka, J.; Peřina ml., Jan
2014-01-01
Roč. 90, č. 3 (2014), "033428-1"-"033428-10" ISSN 1050-2947 Institutional support: RVO:68378271 Keywords : quantum correlation * ionizing system Subject RIV: BH - Optics , Masers, Lasers Impact factor: 2.808, year: 2014
International Nuclear Information System (INIS)
Manolescu, A.; Mezincescu, G.A.
1987-05-01
The best possible constraints of the static response in terms of two particle correlation functions, which follow from their integral representation, are analysed for homogeneous states of multicomponent systems of charged particles.(authors)
Ruaro, B; Sulli, A; Pizzorni, C; Paolino, S; Smith, V; Cutolo, M
2016-05-01
To correlate blood perfusion (BP) values assessed by laser speckle contrast analysis (LASCA) in selected skin areas of hands and face with nailfold capillary damage scores in systemic sclerosis (SSc) patients. Seventy SSc patients (mean SSc duration 6 ± 5 years) and 70 volunteer healthy subjects were enrolled after informed consent. LASCA was performed at different areas of the face (forehead, tip of nose, zygomas and perioral region) and at dorsal and volar regions of hands. Microvascular damage was assessed and scored by nailfold videocapillaroscopy (NVC) and the microangiopathy evolution score (MES) was calculated. SSc patients showed a significantly lower BP than healthy subjects at fingertips, periungual areas and palm of hands (pnailfold capillaroscopy scores of microangiopathy. Copyright © 2016. Published by Elsevier Inc.
International Nuclear Information System (INIS)
Pereira, D.; Zambrano, C.; Martin L, M.
1998-01-01
In the present work it is proposed a method for the characterization of the irregularities present in the edges of malignant leisure of central nervous system over axial images generated through Nuclear magnetic Resonance by images. Through the use of techniques of digital images processing was possible to locate, extract and generate temporal series. These temporal series were utilized using the correlation dimension concept for producing a parameter which takes different values depending of the leisure type. It is demonstrated that this type of analysis suffers in a very acceptable form independently of the errors which can be generate by the fact that in the practice of temporal series obtained they are composed by a reduced number of points. (Author)
Directory of Open Access Journals (Sweden)
Giacomo Leonardi
2007-12-01
Full Text Available Ã¯Â»Â¿This paper investigates the impact of several equalization techniques for multicarrier code division multiple access systems on the performance at both lower and upper layers (i.e., physical and TCP layers. Classical techniques such as maximal ratio combining, equal gain combining, orthogonality restoring combining, minimum mean square error, as well as a partial equalization (PE are investigated in time- and frequency-correlated fading channels with various numbers of interferers. Their impact on the performance at upper level is then studied. The results are obtained through an integrated simulation platform carefully reproducing all main aspects affecting the quality of service perceived by the final user, allowing an investigation of the real gain produced by signal processing techniques at TCP level.
Christensen, E. J.; Haines, B. J.; Mccoll, K. C.; Nerem, R. S.
1994-01-01
We have compared Global Positioning System (GPS)-based dynamic and reduced-dynamic TOPEX/Poseidon orbits over three 10-day repeat cycles of the ground-track. The results suggest that the prelaunch joint gravity model (JGM-1) introduces geographically correlated errors (GCEs) which have a strong meridional dependence. The global distribution and magnitude of these GCEs are consistent with a prelaunch covariance analysis, with estimated and predicted global rms error statistics of 2.3 and 2.4 cm rms, respectively. Repeating the analysis with the post-launch joint gravity model (JGM-2) suggests that a portion of the meridional dependence observed in JGM-1 still remains, with global rms error of 1.2 cm.
Holstein-Primakoff representation and supercoherent states for strongly correlated electron systems
International Nuclear Information System (INIS)
Azakov, S.
1999-09-01
First we show that the algebra of operators entering the Hamiltonian of the t-J model describing the strongly correlated electron system is graded spl(2.1) algebra. Then after a brief discussion of its atypical representations we construct the Holstein-Primakoff nonlinear realization of these operators which allows to carry out the systematic semiclassical approximation, similarly to the spin-wave theory of localized magnetism. The fact that the t-J model describes the itinerant magnetism is reflected in the presence of the spinless fermions. For the supersymmetric spl(2.1) algebra the supercoherent states are proposed and the partition function of the t-J model is represented as a path integral with the help of these states. (author)
Non-equilibrium correlations and entanglement in a semiconductor hybrid circuit-QED system
International Nuclear Information System (INIS)
Contreras-Pulido, L D; Emary, C; Brandes, T; Aguado, Ramón
2013-01-01
We present a theoretical study of a hybrid circuit-quantum electrodynamics system composed of two semiconducting charge-qubits confined in a microwave resonator. The qubits are defined in terms of the charge states of two spatially separated double quantum dots (DQDs) which are coupled to the same photon mode in the microwave resonator. We analyse a transport setup where each DQD is attached to electronic reservoirs and biased out-of-equilibrium by a large voltage, and study how electron transport across each DQD is modified by the coupling to the common resonator. In particular, we show that the inelastic current through each DQD reflects an indirect qubit–qubit interaction mediated by off-resonant photons in the microwave resonator. As a result of this interaction, both charge qubits stay entangled in the steady (dissipative) state. Finite shot noise cross-correlations between currents across distant DQDs are another manifestation of this nontrivial steady-state entanglement. (paper)
International Nuclear Information System (INIS)
Zhou Yu-Rong
2011-01-01
This paper considers the stochastic resonance for a time-delayed mono-stable system, driven by correlated multiplicative and additive white noise. It finds that the output signal-to-noise ratio (SNR) varies non-monotonically with the delayed times. The SNR varies non-monotonically with the increase of the intensities of the multiplicative and additive noise, with the increase of the correlation strength between the two noises, as well as with the system parameter. (general)
Norris, Zach; Mawson, Cara; Johnson, Kyron; Kessler, Sarah; Rebecca, Anne; Wolf, Nathan; Lim, Michael; Nucci, Nathaniel
Reverse micelles are molecular complexes that encapsulate a nanoscale pool of water in a surfactant shell dissolved in non-polar solvent. These complexes have a wide range of applications, and in all cases, the degree to which reverse micelles (RM) exchange their contents is relevant for their use. Despite its importance, this aspect of RM behavior is poorly understood. Photolithography is employed here to create micro and nano scale fluidic systems in which mixing rates can be precisely measured using fluorescence correlation spectroscopy (FCS). Micro-channel patterns are etched using reactive ion etching process into a layer of silicon dioxide on crystalline silicon substrates. Solutions containing mixtures of reverse micelles, proteins, and fluorophores are placed into reservoirs in the patterns, while diffusion and exchange between RMs is monitored using a FCS system built from a modified confocal Raman spectrometer. Using this approach, the diffusion and exchange rates for RM systems are measured as a function of the components of the RM mixture. Funding provided by Rowan University.
Tsai, Meng-Yen; Creedon, Niamh; Brightbill, Eleanor; Pavlidis, Spyridon; Brown, Billyde; Gray, Darren W.; Shields, Niall; Sayers, Ríona; Mooney, Mark H.; O'Riordan, Alan; Vogel, Eric M.
2017-08-01
A fully integrated system that combines extended gate field-effect transistor (EGFET)-based potentiometric biosensors and electrochemical impedance spectroscopy (EIS)-based biosensors has been demonstrated. This integrated configuration enables the sequential measurement of the same immunological binding event on the same sensing surface and consequently sheds light on the fundamental origins of sensing signals produced by FET and EIS biosensors, as well as the correlation between the two. Detection of both the bovine serum albumin (BSA)/anti-BSA model system in buffer solution and bovine parainfluenza antibodies in complex blood plasma samples was demonstrated using the integrated biosensors. Comparison of the EGFET and EIS sensor responses reveals similar dynamic ranges, while equivalent circuit modeling of the EIS response shows that the commonly reported total impedance change (ΔZtotal) is dominated by the change in charge transfer resistance (Rct) rather than surface capacitance (Csurface). Using electrochemical kinetics and the Butler-Volmer equation, we unveil that the surface potential and charge transfer resistance, measured by potentiometric and impedance biosensors, respectively, are, in fact, intrinsically linked. This observation suggests that there is no significant gain in using the FET/EIS integrated system and leads to the demonstration that low-cost EGFET biosensors are sufficient as a detection tool to resolve the charge information of biomolecules for practical sensing applications.
Preparation of a data bank system for isotope correlation on spent nuclear fuels
International Nuclear Information System (INIS)
Nakahara, Yoshinori; Umezawa, Hirokazu
1981-11-01
For the purposes of studying isotope correlation on spent nuclear fuels and its applicability to safeguards technology of nuclear material, a data bank system has been prepared on the basis of a FACOM M200 computer in JAERI. Spent fuels data of fabrication, irradiation history, reactor operator's burnup calculation, and reprocessing are stored in four kinds of data files: (1) Fuel assembly data file, (2) reprocessing batch data file, (3) plutonium product data file, and (4) uranium product data file. Corrections for decay and for mixing from adjoining batches are made and the corrected data are also kept in the files. A wide variety of variables may be derived from the isotopic and other data stored and subjected to optional statistical treatments such as regression analysis and paired comparison. Computer language used for the system was FORTRAN-IV. The system can be operated in a conversational mode with graphic indication, so that one may proceed such a statistical analysis immediately under various conditions of calculation. (author)
Correlation between the meteorological data acquisition systems of the Centro Experimental ARAMAR
International Nuclear Information System (INIS)
Oliveira, Rando M.; Beu, Cássia M.L.
2017-01-01
Centro Experimental ARAMAR (CEA) is a Brazilian Navy Technological Center located in the rural area of lperó (São Paulo State), about 10-km distant from the nearest urban area. One of the most important activities at CEA is the nuclear fuel cycle research, as well as the development of a small-scale pressurized water reactor (PWR) land based prototype, The Laboratório Radioecológico (LAR E) is responsible for the meteorological observation program which relies on an automatic data collection system, The following variables are continuously measured: pressure, precipitation, wind speed, wind direction, temperature and relative humidity, The obtained data is refined and used in the annual reports to Comissão Nacional de Energia Nuclear (CNEN), and are an important input data for atmospheric dispersion models. Due to the construction of the Laboratório de Geraç!o Nucleoclétrica (LABGENE), it will be necessary to change tbe location of the towers and meteorological sensors, Thus, since 20 14, a new set of towers and sensors (Torre Nova) are in operation. The new location is 900 m distant from the old set (Torre Velha). Therefore, CEA has currently two meteorological data acquisition systems operating concurrently for approximately three years. The present work aims to compare the meteorological data of both systems in order to verify their agreement. The meteorological time series of both systems were submitted to a statistical analysis to evaluate their correlation. The results of this work confirm the compatibility of the two systems, showing that the Torre Velha can be deactivated without impairment to the meteorological time series. (author)
Correlation between the meteorological data acquisition systems of the Centro Experimental ARAMAR
Energy Technology Data Exchange (ETDEWEB)
Oliveira, Rando M.; Beu, Cássia M.L., E-mail: rando.oliveira@marinha.mil.br, E-mail: cassia.beu@marinha.mil.br [Centro Tecnológico da Marinha em São Paulo (CEA/CTMSP), Iperó, SP (Brazil). Centro Experimental ARAMAR
2017-07-01
Centro Experimental ARAMAR (CEA) is a Brazilian Navy Technological Center located in the rural area of lperó (São Paulo State), about 10-km distant from the nearest urban area. One of the most important activities at CEA is the nuclear fuel cycle research, as well as the development of a small-scale pressurized water reactor (PWR) land based prototype, The Laboratório Radioecológico (LAR E) is responsible for the meteorological observation program which relies on an automatic data collection system, The following variables are continuously measured: pressure, precipitation, wind speed, wind direction, temperature and relative humidity, The obtained data is refined and used in the annual reports to Comissão Nacional de Energia Nuclear (CNEN), and are an important input data for atmospheric dispersion models. Due to the construction of the Laboratório de Geraç!o Nucleoclétrica (LABGENE), it will be necessary to change tbe location of the towers and meteorological sensors, Thus, since 20 14, a new set of towers and sensors (Torre Nova) are in operation. The new location is 900 m distant from the old set (Torre Velha). Therefore, CEA has currently two meteorological data acquisition systems operating concurrently for approximately three years. The present work aims to compare the meteorological data of both systems in order to verify their agreement. The meteorological time series of both systems were submitted to a statistical analysis to evaluate their correlation. The results of this work confirm the compatibility of the two systems, showing that the Torre Velha can be deactivated without impairment to the meteorological time series. (author)
High-resolution x-ray scattering studies of charge ordering in highly correlated electron systems
International Nuclear Information System (INIS)
Ghazi, M.E.
2002-01-01
Many important properties of transition metal oxides such as, copper oxide high-temperature superconductivity and colossal magnetoresistance (CMR) in manganites are due to strong electron-electron interactions, and hence these systems are called highly correlated systems. These materials are characterised by the coexistence of different kinds of order, including charge, orbital, and magnetic moment. This thesis contains high-resolution X-ray scattering studies of charge ordering in such systems namely the high-T C copper oxides isostructural system, La 2-x Sr x NiO 4 with various Sr concentrations (x = 0.33 - 0.2), and the CMR manganite system, Nd 1/2 Sr 1/2 MnO 3 . It also includes a review of charge ordering in a large variety of transition metal oxides, such as ferrates, vanadates, cobaltates, nickelates, manganites, and cuprates systems, which have been reported to date in the scientific literature. Using high-resolution synchrotron X-ray scattering, it has been demonstrated that the charge stripes exist in a series of single crystals of La 2-x Sr x NiO 4 with Sr concentrations (x = 0.33 - 0.2) at low temperatures. Satellite reflections due to the charge ordering were found with the wavevector (2ε, 0, 1) below the charge ordering transition temperature, T CO , where 2ε is the amount of separation from the corresponding Bragg peak. The charge stripes are shown to be two-dimensional in nature both by measurements of their correlation lengths and by measurement of the critical exponents of the charge stripe melting transition with an anomaly at x = 0.25. The results show by decreasing the hole concentration from the x = 0.33 to 0.2, the well-correlated charge stripes change to a glassy state at x = 0.25. The electronic transition into the charge stripe phase is second-order without any corresponding structural transition. Above the second-order transition critical scattering was observed due to fluctuations into the charge stripe phase. In a single-crystal of Nd
PIKfyve mediates the motility of late endosomes and lysosomes in neuronal dendrites.
Tsuruta, Fuminori; Dolmetsch, Ricardo E
2015-09-25
The endosome/lysosome system in the nervous system is critically important for a variety of neuronal functions such as neurite outgrowth, retrograde transport, and synaptic plasticity. In neurons, the endosome/lysosome system is crucial for the activity-dependent internalization of membrane proteins and contributes to the regulation of lipid level on the plasma membrane. Although homeostasis of membrane dynamics plays important roles in the properties of central nervous systems, it has not been elucidated how endosome/lysosome system is regulated. Here, we report that phosphatidylinositol 3-phosphate 5-kinase (PIKfyve) mediates the motility of late endosomes and lysosomes in neuronal dendrites. Endosomes and lysosomes are highly motile in resting neurons, however knockdown of PIKfyve led to a significant reduction in late endosomes and lysosomes motility. We also found that vesicle acidification is crucial for their motility and PIKfyve is associated with this process indirectly. These data suggest that PIKfyve mediates vesicle motility through the regulation of vesicle integrity in neurons. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
Institute of Scientific and Technical Information of China (English)
Xie Wen-Xian; Xu Wei; Cai Li
2007-01-01
This paper shows the Fokker-Planck equation of a dynamical system driven by coloured cross-correlated white noises in the absence and presence of a small external force. Based on the Fokker-Planck equation and the definition of Shannon's information entropy, the time dependence of entropy flux and entropy production can be calculated. The present results can be used to explain the extremal behaviour of time dependence of entropy flux and entropy production in view of the dissipative parameter γ of the system, coloured cross-correlation time τ and coloured cross-correlation strength λ.
Warren, Sean N.; Kallu, Raj R.; Barnard, Chase K.
2016-11-01
Underground gold mines in Nevada are exploiting increasingly deeper ore bodies comprised of weak to very weak rock masses. The Rock Mass Rating (RMR) classification system is widely used at underground gold mines in Nevada and is applicable in fair to good-quality rock masses, but is difficult to apply and loses reliability in very weak rock mass to soil-like material. Because very weak rock masses are transition materials that border engineering rock mass and soil classification systems, soil classification may sometimes be easier and more appropriate to provide insight into material behavior and properties. The Unified Soil Classification System (USCS) is the most likely choice for the classification of very weak rock mass to soil-like material because of its accepted use in tunnel engineering projects and its ability to predict soil-like material behavior underground. A correlation between the RMR and USCS systems was developed by comparing underground geotechnical RMR mapping to laboratory testing of bulk samples from the same locations, thereby assigning a numeric RMR value to the USCS classification that can be used in spreadsheet calculations and geostatistical analyses. The geotechnical classification system presented in this paper including a USCS-RMR correlation, RMR rating equations, and the Geo-Pick Strike Index is collectively introduced as the Weak Rock Mass Rating System (W-RMR). It is the authors' hope that this system will aid in the classification of weak rock masses and more usable design tools based on the RMR system. More broadly, the RMR-USCS correlation and the W-RMR system help define the transition between engineering soil and rock mass classification systems and may provide insight for geotechnical design in very weak rock masses.
8-Channel acquisition system for Time-Correlated Single-Photon Counting.
Antonioli, S; Miari, L; Cuccato, A; Crotti, M; Rech, I; Ghioni, M
2013-06-01
Nowadays, an increasing number of applications require high-performance analytical instruments capable to detect the temporal trend of weak and fast light signals with picosecond time resolution. The Time-Correlated Single-Photon Counting (TCSPC) technique is currently one of the preferable solutions when such critical optical signals have to be analyzed and it is fully exploited in biomedical and chemical research fields, as well as in security and space applications. Recent progress in the field of single-photon detector arrays is pushing research towards the development of high performance multichannel TCSPC systems, opening the way to modern time-resolved multi-dimensional optical analysis. In this paper we describe a new 8-channel high-performance TCSPC acquisition system, designed to be compact and versatile, to be used in modern TCSPC measurement setups. We designed a novel integrated circuit including a multichannel Time-to-Amplitude Converter with variable full-scale range, a D∕A converter, and a parallel adder stage. The latter is used to adapt each converter output to the input dynamic range of a commercial 8-channel Analog-to-Digital Converter, while the integrated DAC implements the dithering technique with as small as possible area occupation. The use of this monolithic circuit made the design of a scalable system of very small dimensions (95 × 40 mm) and low power consumption (6 W) possible. Data acquired from the TCSPC measurement are digitally processed and stored inside an FPGA (Field-Programmable Gate Array), while a USB transceiver allows real-time transmission of up to eight TCSPC histograms to a remote PC. Eventually, the experimental results demonstrate that the acquisition system performs TCSPC measurements with high conversion rate (up to 5 MHz/channel), extremely low differential nonlinearity (<0.04 peak-to-peak of the time bin width), high time resolution (down to 20 ps Full-Width Half-Maximum), and very low crosstalk between channels.
Quantum correlations between each two-level system in a pair of atoms and general coherent fields
Directory of Open Access Journals (Sweden)
S. Abdel-Khalek
Full Text Available The quantitative description of the quantum correlations between each two-level system in a two-atom system and the coherent fields initially defined in a coherent state in the framework of power-law potentials (PLPCSs is considered. Specifically, we consider two atoms locally interacting with PLPCSs and take into account the different terms of interactions, the entanglement and quantum discord are studied including the time-dependent coupling and photon transition effects. Using the monogamic relation between the entanglement of formation and quantum discord in tripartite systems, we show that the control and preservation of the different kinds of quantum correlations greatly benefit from the combination of the choice of the physical quantities. Finally, we explore the link between the dynamical behavior of quantum correlations and nonclassicality of the fields with and without atomic motion effect. Keywords: Quantum correlations, Monogamic relation, Coherent states, Power-law potentials, Wehrl entropy
Short-ranged radial and tensor correlations in nuclear many-body systems
International Nuclear Information System (INIS)
Neff, T.; Feldmeier, H.
2003-01-01
The unitary correlation operator method (UCOM) is applied to realistic potentials. The effects of tensor correlations are investigated. The resulting phase shift equivalent correlated interactions are used in the no-core shell model for light nuclei and for mean-field calculations in the Fermionic Molecular Dynamics model for nuclei up to mass A=48. (orig.)
International Nuclear Information System (INIS)
Giraud, B.G.; Heumann, J.M.; Lapedes, A.S.
1999-01-01
The fact that correlation does not imply causation is well known. Correlation between variables at two sites does not imply that the two sites directly interact, because, e.g., correlation between distant sites may be induced by chaining of correlation between a set of intervening, directly interacting sites. Such 'noncausal correlation' is well understood in statistical physics: an example is long-range order in spin systems, where spins which have only short-range direct interactions, e.g., the Ising model, display correlation at a distance. It is less well recognized that such long-range 'noncausal' correlations can in fact be stronger than the magnitude of any causal correlation induced by direct interactions. We call this phenomenon superadditive correlation (SAC). We demonstrate this counterintuitive phenomenon by explicit examples in (i) a model spin system and (ii) a model continuous variable system, where both models are such that two variables have multiple intervening pathways of indirect interaction. We apply the technique known as decimation to explain SAC as an additive, constructive interference phenomenon between the multiple pathways of indirect interaction. We also explain the effect using a definition of the collective mode describing the intervening spin variables. Finally, we show that the SAC effect is mirrored in information theory, and is true for mutual information measures in addition to correlation measures. Generic complex systems typically exhibit multiple pathways of indirect interaction, making SAC a potentially widespread phenomenon. This affects, e.g., attempts to deduce interactions by examination of correlations, as well as, e.g., hierarchical approximation methods for multivariate probability distributions, which introduce parameters based on successive orders of correlation. copyright 1999 The American Physical Society
Density of states and excitonic condensation in the double layer correlated systems
Energy Technology Data Exchange (ETDEWEB)
Apinyan, V., E-mail: v.apinyan@int.pan.wroc.pl; Kopeć, T.K.
2016-01-15
We consider the single-particle density of states (DOS) in the strongly correlated double layer (DL) system, without applied external fields. We demonstrate an unusual collapse effect in the spectrum of the normal single-particle spectral function at the particular high-symmetry point corresponding to the specific bunching-point solution of the chemical potential in the Frenkel channel. We show that at the low-temperature limit the anomalous spectral function obeys a concave like structure, which is directly related to the interlayer pair formation and condensation. We calculate the normal DOS functions, and we find their temperature dependence for different values of the interlayer Coulomb interaction parameter. We show that the normal electron and hole DOS functions demonstrate typical condensates double peak structures on the background of the excitonic pair formation quasiparticle spectra and we have found the evidence of the hybridization gap in the case of high-temperature limit, and small interlayer coupling parameter. Meanwhile, we show a possible crossover from the excitonic condensate regime into the band insulator state. The structure of the normal DOS spectra, in the Frenkel channel and for the strong interlayer coupling regime, is found gapless for all temperature limits, which clearly indicates the strong coherence effects in the DL structure, and the excitonic condensates therein. We have shown that the excitonic pair formation and pair condensation occur simultaneously in the DL system, in contrast with the purely three-dimensional (3D) or two-dimensional cases (2D), discussed previously.
Generalized correlation integral vectors: A distance concept for chaotic dynamical systems
Energy Technology Data Exchange (ETDEWEB)
Haario, Heikki, E-mail: heikki.haario@lut.fi [School of Engineering Science, Lappeenranta University of Technology, Lappeenranta (Finland); Kalachev, Leonid, E-mail: KalachevL@mso.umt.edu [Department of Mathematical Sciences, University of Montana, Missoula, Montana 59812-0864 (United States); Hakkarainen, Janne [Earth Observation Unit, Finnish Meteorological Institute, Helsinki (Finland)
2015-06-15
Several concepts of fractal dimension have been developed to characterise properties of attractors of chaotic dynamical systems. Numerical approximations of them must be calculated by finite samples of simulated trajectories. In principle, the quantities should not depend on the choice of the trajectory, as long as it provides properly distributed samples of the underlying attractor. In practice, however, the trajectories are sensitive with respect to varying initial values, small changes of the model parameters, to the choice of a solver, numeric tolerances, etc. The purpose of this paper is to present a statistically sound approach to quantify this variability. We modify the concept of correlation integral to produce a vector that summarises the variability at all selected scales. The distribution of this stochastic vector can be estimated, and it provides a statistical distance concept between trajectories. Here, we demonstrate the use of the distance for the purpose of estimating model parameters of a chaotic dynamic model. The methodology is illustrated using computational examples for the Lorenz 63 and Lorenz 95 systems, together with a framework for Markov chain Monte Carlo sampling to produce posterior distributions of model parameters.
Structures and Correlations in Ideally Aligned Polar Gay-Berne Systems
International Nuclear Information System (INIS)
Longa, L.; Cholewiak, G.; Stelzer, J.
2000-01-01
We study an ideally oriented system of Gay-Berne particles with embedded longitudinal dipole moments. While keeping the translational degrees of freedom of the molecules unrestricted we assume that their dipoles can be oriented either parallel or antiparallel to the positive z axis of the laboratory frame. At high temperatures, this frustrated Gay-Berne mesogen exhibits an ideally oriented nematic phase, which is the reference state of the system. In the limit of vanishing dipole moment nematic, smectic-A and smectic B phases are stable. Interestingly, by changing the magnitude and location of the molecular dipole in the nematic reference state we found dipole-induced smectic A, smectic B and tetragonal crystal phases, in addition to crystalline structures with smectic A d and A 2 -like dipolar organization. Various singlet, pair and triplet distribution functions were evaluated to elucidate short and long range organization in these phases. In particular, the importance of triplet correlations for a proper understanding of the structures and their local, dipolar organization is demonstrated. (author)
Directory of Open Access Journals (Sweden)
Hanlun Li
2016-01-01
Full Text Available In the past few years, many multispectral systems which consist of several identical monochrome cameras equipped with different bandpass filters have been developed. However, due to the significant difference in the intensity between different band images, image registration becomes very difficult. Considering the common structural characteristic of the multispectral systems, this paper proposes an effective method for registering different band images. First we use the phase correlation method to calculate the parameters of a coarse-offset relationship between different band images. Then we use the scale invariant feature transform (SIFT to detect the feature points. For every feature point in a reference image, we can use the coarse-offset parameters to predict the location of its matching point. We only need to compare the feature point in the reference image with the several near feature points from the predicted location instead of the feature points all over the input image. Our experiments show that this method does not only avoid false matches and increase correct matches, but also solve the matching problem between an infrared band image and a visible band image in cases lacking man-made objects.
A study of pile-up in integrated time-correlated single photon counting systems.
Arlt, Jochen; Tyndall, David; Rae, Bruce R; Li, David D-U; Richardson, Justin A; Henderson, Robert K
2013-10-01
Recent demonstration of highly integrated, solid-state, time-correlated single photon counting (TCSPC) systems in CMOS technology is set to provide significant increases in performance over existing bulky, expensive hardware. Arrays of single photon single photon avalanche diode (SPAD) detectors, timing channels, and signal processing can be integrated on a single silicon chip with a degree of parallelism and computational speed that is unattainable by discrete photomultiplier tube and photon counting card solutions. New multi-channel, multi-detector TCSPC sensor architectures with greatly enhanced throughput due to minimal detector transit (dead) time or timing channel dead time are now feasible. In this paper, we study the potential for future integrated, solid-state TCSPC sensors to exceed the photon pile-up limit through analytic formula and simulation. The results are validated using a 10% fill factor SPAD array and an 8-channel, 52 ps resolution time-to-digital conversion architecture with embedded lifetime estimation. It is demonstrated that pile-up insensitive acquisition is attainable at greater than 10 times the pulse repetition rate providing over 60 dB of extended dynamic range to the TCSPC technique. Our results predict future CMOS TCSPC sensors capable of live-cell transient observations in confocal scanning microscopy, improved resolution of near-infrared optical tomography systems, and fluorescence lifetime activated cell sorting.
Directory of Open Access Journals (Sweden)
Hongtao Yang
2018-01-01
Full Text Available This paper proposes a novel strong tracking filter (STF, which is suitable for dealing with the filtering problem of nonlinear systems when the following cases occur: that is, the constructed model does not match the actual system, the measurements have the one-step random delay, and the process and measurement noises are correlated at the same epoch. Firstly, a framework of decoupling filter (DF based on equivalent model transformation is derived. Further, according to the framework of DF, a new extended Kalman filtering (EKF algorithm via using first-order linearization approximation is developed. Secondly, the computational process of the suboptimal fading factor is derived on the basis of the extended orthogonality principle (EOP. Thirdly, the ultimate form of the proposed STF is obtained by introducing the suboptimal fading factor into the above EKF algorithm. The proposed STF can automatically tune the suboptimal fading factor on the basis of the residuals between available and predicted measurements and further the gain matrices of the proposed STF tune online to improve the filtering performance. Finally, the effectiveness of the proposed STF has been proved through numerical simulation experiments.
Neuromimetic Circuits with Synaptic Devices Based on Strongly Correlated Electron Systems
Ha, Sieu D.; Shi, Jian; Meroz, Yasmine; Mahadevan, L.; Ramanathan, Shriram
2014-12-01
Strongly correlated electron systems such as the rare-earth nickelates (R NiO3 , R denotes a rare-earth element) can exhibit synapselike continuous long-term potentiation and depression when gated with ionic liquids; exploiting the extreme sensitivity of coupled charge, spin, orbital, and lattice degrees of freedom to stoichiometry. We present experimental real-time, device-level classical conditioning and unlearning using nickelate-based synaptic devices in an electronic circuit compatible with both excitatory and inhibitory neurons. We establish a physical model for the device behavior based on electric-field-driven coupled ionic-electronic diffusion that can be utilized for design of more complex systems. We use the model to simulate a variety of associate and nonassociative learning mechanisms, as well as a feedforward recurrent network for storing memory. Our circuit intuitively parallels biological neural architectures, and it can be readily generalized to other forms of cellular learning and extinction. The simulation of neural function with electronic device analogs may provide insight into biological processes such as decision making, learning, and adaptation, while facilitating advanced parallel information processing in hardware.
From plane waves to local Gaussians for the simulation of correlated periodic systems
International Nuclear Information System (INIS)
Booth, George H.; Tsatsoulis, Theodoros; Grüneis, Andreas; Chan, Garnet Kin-Lic
2016-01-01
We present a simple, robust, and black-box approach to the implementation and use of local, periodic, atom-centered Gaussian basis functions within a plane wave code, in a computationally efficient manner. The procedure outlined is based on the representation of the Gaussians within a finite bandwidth by their underlying plane wave coefficients. The core region is handled within the projected augment wave framework, by pseudizing the Gaussian functions within a cutoff radius around each nucleus, smoothing the functions so that they are faithfully represented by a plane wave basis with only moderate kinetic energy cutoff. To mitigate the effects of the basis set superposition error and incompleteness at the mean-field level introduced by the Gaussian basis, we also propose a hybrid approach, whereby the complete occupied space is first converged within a large plane wave basis, and the Gaussian basis used to construct a complementary virtual space for the application of correlated methods. We demonstrate that these pseudized Gaussians yield compact and systematically improvable spaces with an accuracy comparable to their non-pseudized Gaussian counterparts. A key advantage of the described method is its ability to efficiently capture and describe electronic correlation effects of weakly bound and low-dimensional systems, where plane waves are not sufficiently compact or able to be truncated without unphysical artifacts. We investigate the accuracy of the pseudized Gaussians for the water dimer interaction, neon solid, and water adsorption on a LiH surface, at the level of second-order Møller–Plesset perturbation theory.
Design and development of correlation techniques to maintain a space surveillance system catalogue
Olmedo, E.; Sánchez Ortiz, Noelia; Lerate, Mercedes; Belló-Mora, Miguel; Klinkrad, H.
2009-10-01
A growing interest exists in a future, autonomous European Space Surveillance System (ESSS). Currently, most of the knowledge about Earth-orbiting space objects is based on information provided by the USASPACECOM. This paper presents the required initial orbit determination (IOD) and correlation techniques to process optical measurements. Former studies were focused on the handling of radar measurements, which are summarised with the aim of describing a global procedure for processing hybrid measurement types (combination of radar and optic data for catalogue maintenance). The introduction of manoeuvres are presented due to their importance in the space object catalogue maintenance. The detection of uncatalogued objects and the successful correlation of already catalogued objects involve two different tasks for telescopes: survey and tasking. Assumptions for both strategies are developed on the basis of the previous work developed at the University of Berne (see [T. Flohrer, T. Schildknecht, R. Musci, E. Stöveken, Performance estimation for GEO space surveillance, Advances in Space Research 35 (2005). [1]; T. Flohrer, T. Schildknecht, R. Musci, Proposed strategies for optical observations in a future European Space Surveillance Network, presented in the 36th COSPAR Scientific Assembly (2006). [2]; R. Musci, T. Schildknecht, M. Ploner, Orbit improvement for GEO objects using follow-up observations, Advances in Space Research 34 (2004). [3]; R. Musci, T. Schildknecht, M. Ploner, G. Beutler, Orbit improvement for GTO objects using follow-up observations, Advances in Space Research 35 (2005). [4]; R. Musci, T. Schildknecht, T. Flohrer, G. Beutler, Concept for a catalogue of space debris in GEO, Proceedings of the Fourth European Conference on Space Debris, (ESA SP-587, 2005). [5
From plane waves to local Gaussians for the simulation of correlated periodic systems
Energy Technology Data Exchange (ETDEWEB)
Booth, George H., E-mail: george.booth@kcl.ac.uk [Department of Physics, King’s College London, Strand, London WC2R 2LS (United Kingdom); Tsatsoulis, Theodoros; Grüneis, Andreas, E-mail: a.grueneis@fkf.mpg.de [Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart (Germany); Chan, Garnet Kin-Lic [Frick Laboratory, Department of Chemistry, Princeton University, Princeton, New Jersey 08544 (United States)
2016-08-28
We present a simple, robust, and black-box approach to the implementation and use of local, periodic, atom-centered Gaussian basis functions within a plane wave code, in a computationally efficient manner. The procedure outlined is based on the representation of the Gaussians within a finite bandwidth by their underlying plane wave coefficients. The core region is handled within the projected augment wave framework, by pseudizing the Gaussian functions within a cutoff radius around each nucleus, smoothing the functions so that they are faithfully represented by a plane wave basis with only moderate kinetic energy cutoff. To mitigate the effects of the basis set superposition error and incompleteness at the mean-field level introduced by the Gaussian basis, we also propose a hybrid approach, whereby the complete occupied space is first converged within a large plane wave basis, and the Gaussian basis used to construct a complementary virtual space for the application of correlated methods. We demonstrate that these pseudized Gaussians yield compact and systematically improvable spaces with an accuracy comparable to their non-pseudized Gaussian counterparts. A key advantage of the described method is its ability to efficiently capture and describe electronic correlation effects of weakly bound and low-dimensional systems, where plane waves are not sufficiently compact or able to be truncated without unphysical artifacts. We investigate the accuracy of the pseudized Gaussians for the water dimer interaction, neon solid, and water adsorption on a LiH surface, at the level of second-order Møller–Plesset perturbation theory.
Directory of Open Access Journals (Sweden)
Shungudzemwoyo P. Garaba
2015-12-01
Full Text Available Societal awareness of changes in the environment and climate has grown rapidly, and there is a need to engage citizens in gathering relevant scientific information to monitor environmental changes due to recognition that citizens are a potential source of critical information. The apparent colour of natural waters is one aspect of our aquatic environment that is easy to detect and an essential complementary optical water quality indicator. Here we present the results and explore the utility of the Forel-Ule colour index (FUI scale as a proxy for different properties of natural waters. A FUI scale is used to distinguish the apparent colours of different natural surface water masses. Correlation analysis was completed in an effort to determine the constituents of natural waters related to FUI. Strong correlations with turbidity, Secchi-disk depth, and coloured dissolved organic material suggest the FUI is a good indicator of changes related to other constituents of water. The increase in the number of tools capable of determining the FUI colours, (i ocean colour remote sensing products; (ii a handheld scale; and (iii a mobile device app, make it a versatile relative measure of water quality. It has the potential to provide higher spatial and temporal resolution of data for a modernized classification of optical water quality. This FUI colour system has been favoured by several scientists in the last century because it is affordable and easy to use and provides indicative information about the colour of water and the water constituents producing that colour. It is therefore within the scope of a growing interest in the application and usefulness of basic measurement methodologies with the potential to provide timely benchmark information about the environment to the public, scientists and policymakers.
Garaba, Shungudzemwoyo P; Friedrichs, Anna; Voß, Daniela; Zielinski, Oliver
2015-12-18
Societal awareness of changes in the environment and climate has grown rapidly, and there is a need to engage citizens in gathering relevant scientific information to monitor environmental changes due to recognition that citizens are a potential source of critical information. The apparent colour of natural waters is one aspect of our aquatic environment that is easy to detect and an essential complementary optical water quality indicator. Here we present the results and explore the utility of the Forel-Ule colour index (FUI) scale as a proxy for different properties of natural waters. A FUI scale is used to distinguish the apparent colours of different natural surface water masses. Correlation analysis was completed in an effort to determine the constituents of natural waters related to FUI. Strong correlations with turbidity, Secchi-disk depth, and coloured dissolved organic material suggest the FUI is a good indicator of changes related to other constituents of water. The increase in the number of tools capable of determining the FUI colours, (i) ocean colour remote sensing products; (ii) a handheld scale; and (iii) a mobile device app, make it a versatile relative measure of water quality. It has the potential to provide higher spatial and temporal resolution of data for a modernized classification of optical water quality. This FUI colour system has been favoured by several scientists in the last century because it is affordable and easy to use and provides indicative information about the colour of water and the water constituents producing that colour. It is therefore within the scope of a growing interest in the application and usefulness of basic measurement methodologies with the potential to provide timely benchmark information about the environment to the public, scientists and policymakers.
International Nuclear Information System (INIS)
Zhou Guangyu; Han Xuemei; Jin Ling
2013-01-01
Objective: To investigate the correlation between cranial magnetic resonance imaging (MRI) findings and autoantibody levels in patients with neuropsychiatric systemic lupus erythematosus (NPSLE), and to elucidate the role of MRI findings in predicting the prognosis of NPSLE. Methods: In total, 36 well-documented cases of NPSLE diagnosed definitely were selected. All the patients were divided into survival group (n=27) and dead group (n=9). Anti-nuclear antibodies and anti-dsDNA antibodies in serum were detected by indirect immunofluorescence and colloidal gold spot penetration method, respectively. Immunoblotting method was used to detect anti-Sm, anti-SSA, anti-SSB, anti U1-RNP, and anti-ribosomal P protein antibodies. Anti-cardiolipin antibody (ACL) was detected byELISA method. The correlation between MRI findings of cerebral lesions and autoantibodies, and prognosis was analyzed. Results: Cranial MRI scans on admission were abnormal in 32 patients (88.9% ), among which 21 cases showed diffuse manifestations, 10 cases showed focal lesion in brain and 1 case showed brain atrophy. The diffuse lesion on MRI showed multiple spotty or patchy normal intensity signal on T 1 -weighted image (T 1 WI) and high-intensity signal changes on T 2 -weighted image (T 2 WI). The focal lesion showed single spotty or patchy normal intensity signal on T 1 WI and high-intensity signal changes on T 2 WI. The lesion sites included basal ganglia, subcortical white matter, anterior and posterior horn of lateral ventricle, semiovale center, cerebral cortex, brainstem and cerebellum. Of 9 patients in dead group, 6 cases presented with focal lesion and the percentage of focal lesion cases in dead group was significantly higher than that in survival group (P<0.01). The percentages of lesion number in brainstem and basal ganglia in dead group were 11.5% and 26.9% , respectively, which were significantly higher than those in survival group (P<0.05 or P<0.01). The positive rate of ACL in cases
Energy Technology Data Exchange (ETDEWEB)
Mohamed, A.-B.A., E-mail: abdelbastm@yahoo.com [College of Sciences and Humanities, Prince Sattam Bin Abdulaziz University, Al-Aflaj (Saudi Arabia); Faculty of Science, Assiut University, Assiut (Egypt); Joshi, A., E-mail: mcbamji@gmail.com [Physics Department, Adelphi University Garden City, NY 11530 (United States); Department of Physics and Optical Engineering, RHIT, Terra Haute IN 47803 (United States); Hassan, S.S., E-mail: shoukryhassan@hotmail.com [Department of Mathematics, College of Science, University of Bahrain, P.O. Box 32038 (Bahrain)
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 correlations 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.
Entropy excess in strongly correlated Fermi systems near a quantum critical point
Energy Technology Data Exchange (ETDEWEB)
Clark, J.W., E-mail: jwc@wuphys.wustl.edu [McDonnell Center for the Space Sciences and Department of Physics, Washington University, St. Louis, MO 63130 (United States); Zverev, M.V. [Russian Research Centre Kurchatov Institute, Moscow, 123182 (Russian Federation); Moscow Institute of Physics and Technology, Moscow, 123098 (Russian Federation); Khodel, V.A. [Russian Research Centre Kurchatov Institute, Moscow, 123182 (Russian Federation); McDonnell Center for the Space Sciences and Department of Physics, Washington University, St. Louis, MO 63130 (United States)
2012-12-15
A system of interacting, identical fermions described by standard Landau Fermi-liquid (FL) theory can experience a rearrangement of its Fermi surface if the correlations grow sufficiently strong, as occurs at a quantum critical point where the effective mass diverges. As yet, this phenomenon defies full understanding, but salient aspects of the non-Fermi-liquid (NFL) behavior observed beyond the quantum critical point are still accessible within the general framework of the Landau quasiparticle picture. Self-consistent solutions of the coupled Landau equations for the quasiparticle momentum distribution n(p) and quasiparticle energy spectrum {epsilon}(p) are shown to exist in two distinct classes, depending on coupling strength and on whether the quasiparticle interaction is regular or singular at zero momentum transfer. One class of solutions maintains the idempotency condition n{sup 2}(p)=n(p) of standard FL theory at zero temperature T while adding pockets to the Fermi surface. The other solutions are characterized by a swelling of the Fermi surface and a flattening of the spectrum {epsilon}(p) over a range of momenta in which the quasiparticle occupancies lie between 0 and 1 even at T=0. The latter, non-idempotent solution is revealed by analysis of a Poincare mapping associated with the fundamental Landau equation connecting n(p) and {epsilon}(p) and validated by solution of a variational condition that yields the symmetry-preserving ground state. Significantly, this extraordinary solution carries the burden of a large temperature-dependent excess entropy down to very low temperatures, threatening violation of the Nernst Theorem. It is argued that certain low-temperature phase transitions, notably those involving Cooper-pair formation, offer effective mechanisms for shedding the entropy excess. Available measurements in heavy-fermion compounds provide concrete support for such a scenario. - Highlights: Black-Right-Pointing-Pointer Extension of Landau
International Nuclear Information System (INIS)
Schlottmann, P.
1998-01-01
Properties of highly correlated electrons, such as heavy fermion compounds, metal-insulator transitions, one-dimensional conductors and systems of restricted dimensionality are studied theoretically. The main focus is on Kondo insulators and impurity bands due to Kondo holes, the low-temperature magnetoresistivity of heavy fermion alloys, the n-channel Kondo problem, mesoscopic systems and one-dimensional conductors
Akçay, A.E.; Biller, B.
2014-01-01
We consider an assemble-to-order production system where the product demands and the time since the last customer arrival are not independent. The simulation of this system requires a multivariate input model that generates random input vectors with correlated discrete and continuous components. In
Shi, Pei-Ming; Li, Qun; Han, Dong-Ying
2017-06-01
This paper investigates a new asymmetric bistable model driven by correlated multiplicative colored noise and additive white noise. The mean first-passage time (MFPT) and the signal-to-noise ratio (SNR) as the indexes of evaluating the model are researched. Based on the two-state theory and the adiabatic approximation theory, the expressions of MFPT and SNR have been obtained for the asymmetric bistable system driven by a periodic signal, correlated multiplicative colored noise and additive noise. Simulation results show that it is easier to generate stochastic resonance (SR) to adjust the intensity of correlation strength λ. Meanwhile, the decrease of asymmetric coefficient r2 and the increase of noise intensity are beneficial to realize the transition between the two steady states in the system. At the same time, the twice SR phenomena can be observed by adjusting additive white noise and correlation strength. The influence of asymmetry of potential function on the MFPTs in two different directions is different.
PREFACE: International Conference on Strongly Correlated Electron Systems 2014 (SCES2014)
2015-03-01
The 2014 International Conference on Strongly Correlated Electron Systems (SCES) was held in Grenoble from the 7th to 11th of July on the campus of the University of Grenoble. It was a great privilege to have the conference in Grenoble after the series of meetings in Sendai (1992), San Diego (1993), Amsterdam (1994), Goa (1995), Zürich (1996), Paris (1998), Nagano (1999), Ann Arbor (2001), Krakow (2002), Karlsruhe (2004), Vienna (2005), Houston (2007), Buzios (2008), Santa Fe (2010), Cambridge (2011) and Tokyo (2013). Every three years, SCES joins the triennial conference on magnetism ICM. In 2015, ICM will take place in Barcelona. The meeting gathered an audience of 875 participants who actively interacted inside and outside of conference rooms. A large number of posters (530) was balanced with four parallel oral sessions which included 86 invited speakers and 141 short oral contributions. A useful arrangement was the possibility to put poster presentations on the website so participants could see them all through the conference week. Each morning two plenary sessions were held, ending on Friday with experimental and theoretical summaries delivered by Philipp Gegenwart (Augsburg) and Andrew Millis (Columbia). The plenary sessions were given by Gabriel Kotliar (Rutgers), Masashi Kawasaki (Tokyo), Jennifer Hoffman (Harvard), Mathias Vojta (Dresden), Ashvin Vishwanath (Berkeley), Andrea Cavalleri (Hamburg), Marc-Henri Julien (Grenoble), Neil Mathur (Cambridge), Giniyat Khaliullin (Stuttgart), and Toshiro Sakakibara (Tokyo). The parallel oral sessions were prepared by 40 symposium organizers selected by the chairman (Antoine Georges) and co-chairman (Kamran Behnia) of the Program Committee with the supplementary rule that speakers had not delivered an invited talk at the previous SCES conference held in 2013 in Tokyo. Special attention was given to help young researchers via grants to 40 overseas students. Perhaps due to the additional possibility of cheap
International Nuclear Information System (INIS)
Wang Canjun; Wei Qun; Mei Dongcheng
2008-01-01
The associated relaxation time T c and the normalized correlation function C(s) for a tumor cell growth system subjected to color noises are investigated. Using the Novikov theorem and Fox approach, the steady probability distribution is obtained. Based on them, the expressions of T c and C(s) are derived by means of projection operator method, in which the effects of the memory kernels of the correlation function are taken into account. Performing the numerical computations, it is found: (1) With the cross-correlation intensity |λ|, the additive noise intensity α and the multiplicative noise self-correlation time τ 1 increasing, the tumor cell numbers can be restrained; And the cross-correlation time τ 3 , the multiplicative noise intensity D can induce the tumor cell numbers increasing; However, the additive noise self-correlation time τ 2 cannot affect the tumor cell numbers; The relaxation time T c is a stochastic resonant phenomenon, and the distribution curves exhibit a single-maximum structure with D increasing. (2) The cross-correlation strength λ weakens the related activity between two states of the tumor cell numbers at different time, and enhances the stability of the tumor cell growth system in the steady state; On the contrast, τ 1 and τ 3 enhance the related activity between two states at different time; However, τ 2 has no effect on the related activity between two states at different time
Wang, Can-Jun; Wei, Qun; Mei, Dong-Cheng
2008-03-01
The associated relaxation time T and the normalized correlation function C(s) for a tumor cell growth system subjected to color noises are investigated. Using the Novikov theorem and Fox approach, the steady probability distribution is obtained. Based on them, the expressions of T and C(s) are derived by means of projection operator method, in which the effects of the memory kernels of the correlation function are taken into account. Performing the numerical computations, it is found: (1) With the cross-correlation intensity |λ|, the additive noise intensity α and the multiplicative noise self-correlation time τ increasing, the tumor cell numbers can be restrained; And the cross-correlation time τ, the multiplicative noise intensity D can induce the tumor cell numbers increasing; However, the additive noise self-correlation time τ cannot affect the tumor cell numbers; The relaxation time T is a stochastic resonant phenomenon, and the distribution curves exhibit a single-maximum structure with D increasing. (2) The cross-correlation strength λ weakens the related activity between two states of the tumor cell numbers at different time, and enhances the stability of the tumor cell growth system in the steady state; On the contrast, τ and τ enhance the related activity between two states at different time; However, τ has no effect on the related activity between two states at different time.
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.
Energy Technology Data Exchange (ETDEWEB)
Haruki, Masashi; Yahiro, Yukihito; Higashi, Hidenori; Iwai, Yoshio; Arai, Yasuhiko [Kyushu University, FUkuoka (Japan). Graduate School of Engineering
1999-08-01
A modified-Soave-Redlich-Kwong (MSRK) equation of state with an exponent-type mixing rule for the energy parameter and a conventional rule for the size parameter is applied to correlate the phase equilibria for four binary mixtures of water + hydrocarbon (benzene, hexane, decane, and dodecane) systems at high temperatures and pressures. It is noted that good correlation results are obtained by using the mixing rules with interaction parameters between unlike molecules. (author)
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.
Correlations in Many-Body systems from two-time Greens functions
International Nuclear Information System (INIS)
Morawetz, K.; Kohler, H.S.
2000-01-01
The Kadanoff-Baym (KB) equations are solved numerically for infinite nuclear matter. In particular we calculate correlation energies and correlation times. Approximating the Green's functions in the KB collision kernel by the free Green's functions the Levinson equation is obtained. This approximation is valid for weak interactions and/or low densities. It relates to the extended quasi-particle approximation for the spectral function. The Levinson correlation energy reduces for large times to a second order Born approximation for the energy. Comparing the Levinson, Born and KB calculations allows for an estimate of higher order spectral corrections to the correlations. (authors)
Tubman, Norm; Whaley, Birgitta
The development of exponential scaling methods has seen great progress in tackling larger systems than previously thought possible. One such technique, full configuration interaction quantum Monte Carlo, allows exact diagonalization through stochastically sampling of determinants. The method derives its utility from the information in the matrix elements of the Hamiltonian, together with a stochastic projected wave function, which are used to explore the important parts of Hilbert space. However, a stochastic representation of the wave function is not required to search Hilbert space efficiently and new deterministic approaches have recently been shown to efficiently find the important parts of determinant space. We shall discuss the technique of Adaptive Sampling Configuration Interaction (ASCI) and the related heat-bath Configuration Interaction approach for ground state and excited state simulations. We will present several applications for strongly correlated Hamiltonians. This work was supported through the Scientific Discovery through Advanced Computing (SciDAC) program funded by the U.S. Department of Energy, Office of Science, Advanced Scientific Computing Research and Basic Energy Sciences.
Correlated Random Systems Five Different Methods : CIRM Jean-Morlet Chair
Kistler, Nicola
2015-01-01
This volume presents five different methods recently developed to tackle the large scale behavior of highly correlated random systems, such as spin glasses, random polymers, local times and loop soups and random matrices. These methods, presented in a series of lectures delivered within the Jean-Morlet initiative (Spring 2013), play a fundamental role in the current development of probability theory and statistical mechanics. The lectures were: Random Polymers by E. Bolthausen, Spontaneous Replica Symmetry Breaking and Interpolation Methods by F. Guerra, Derrida's Random Energy Models by N. Kistler, Isomorphism Theorems by J. Rosen and Spectral Properties of Wigner Matrices by B. Schlein. This book is the first in a co-edition between the Jean-Morlet Chair at CIRM and the Springer Lecture Notes in Mathematics which aims to collect together courses and lectures on cutting-edge subjects given during the term of the Jean-Morlet Chair, as well as new material produced in its wake. It is targeted at researchers, i...
Finite-Temperature Variational Monte Carlo Method for Strongly Correlated Electron Systems
Takai, Kensaku; Ido, Kota; Misawa, Takahiro; Yamaji, Youhei; Imada, Masatoshi
2016-03-01
A new computational method for finite-temperature properties of strongly correlated electrons is proposed by extending the variational Monte Carlo method originally developed for the ground state. The method is based on the path integral in the imaginary-time formulation, starting from the infinite-temperature state that is well approximated by a small number of certain random initial states. Lower temperatures are progressively reached by the imaginary-time evolution. The algorithm follows the framework of the quantum transfer matrix and finite-temperature Lanczos methods, but we extend them to treat much larger system sizes without the negative sign problem by optimizing the truncated Hilbert space on the basis of the time-dependent variational principle (TDVP). This optimization algorithm is equivalent to the stochastic reconfiguration (SR) method that has been frequently used for the ground state to optimally truncate the Hilbert space. The obtained finite-temperature states allow an interpretation based on the thermal pure quantum (TPQ) state instead of the conventional canonical-ensemble average. Our method is tested for the one- and two-dimensional Hubbard models and its accuracy and efficiency are demonstrated.
Directory of Open Access Journals (Sweden)
Manel Hammami
2017-12-01
Full Text Available The implementation of maximum power point tracking (MPPT schemes by the ripple correlation control (RCC algorithm is presented in this paper. A reference is made to single-phase single-stage multilevel photovoltaic (PV generation systems, when the inverter input variables (PV voltage and PV current have multiple low-frequency (ripple harmonics. The harmonic analysis is carried out with reference to a multilevel configuration consisting of an H-bridge inverter and level doubling network (LDN cell, leading to the multilevel inverter having double the output voltage levels as compared to the basic H-bridge inverter topology (i.e., five levels vs. three levels. The LDN cell is basically a half-bridge fed by a floating capacitor, with self-balancing voltage capability. The multilevel configuration introduces additional PV voltage and current low-frequency harmonics, perturbing the basic implementation of the RCC scheme (based on the second harmonic component, leading to malfunctioning. The proposed RCC algorithm employs the PV current and voltage harmonics at a specific frequency for the estimation of the voltage derivative of power dP/dV (or dI/dV, driving the PV operating point toward the maximum power point (MPP in a faster and more precise manner. The steady-state and transient performances of the proposed RCC-MPPT schemes have been preliminarily tested and compared using MATLAB/Simulink. Results have been verified by experimental tests considering the whole multilevel PV generation system, including real PV modules, multilevel insulated-gate bipolar transistor (IGBT inverters, and utility grids.
Energy Technology Data Exchange (ETDEWEB)
Font-Ribera, Andreu [Institut de Ciències de l' Espai (IEEC-CSIC), E. de Ciències, Torre C5, Bellaterra, Catalonia (Spain); Miralda-Escudé, Jordi, E-mail: font@physik.uzh.ch, E-mail: miralda@icc.ub.edu [Institució Catalana de Recerca i Estudis Avançats, Passeig Lluís Companys 23, 08010 Barcelona, Catalonia (Spain)
2012-07-01
We present a study of the effect of High Column Density (HCD) systems on the Lyα forest correlation function on large scales. We study the effect both numerically, by inserting HCD systems on mock spectra for a specific model, and analytically, in the context of two-point correlations and linear theory. We show that the presence of HCDs substantially contributes to the noise of the correlation function measurement, and systematically alters the measured redshift-space correlation function of the Lyα forest, increasing the value of the density bias factor and decreasing the redshift distortion parameter β{sub α} of the Lyα forest. We provide simple formulae for corrections on these derived parameters, as a function of the mean effective optical depth and bias factor of the host halos of the HCDs, and discuss the conditions under which these expressions should be valid. In practice, precise corrections to the measured parameters of the Lyα forest correlation for the HCD effects are more complex than the simple analytical approximations we present, owing to non-linear effects of the damped wings of the HCD systems and the presence of three-point terms. However, we conclude that an accurate correction for these HCD effects can be obtained numerically and calibrated with observations of the HCD-Lyα cross-correlation. We also discuss an analogous formalism to treat and correct for the contaminating effect of metal lines overlapping the Lyα forest spectra.
Matrix-product states for strongly correlated systems and quantum information processing
International Nuclear Information System (INIS)
Saberi, Hamed
2008-01-01
This thesis offers new developments in matrix-product state theory for studying the strongly correlated systems and quantum information processing through three major projects: In the first project, we perform a systematic comparison between Wilson's numerical renormalization group (NRG) and White's density-matrix renormalization group (DMRG). The NRG method for solving quantum impurity models yields a set of energy eigenstates that have the form of matrix-product states (MPS). White's DMRG for treating quantum lattice problems can likewise be reformulated in terms of MPS. Thus, the latter constitute a common algebraic structure for both approaches. We exploit this fact to compare the NRG approach for the single-impurity Anderson model to a variational matrix-product state approach (VMPS), equivalent to single-site DMRG. For the latter, we use an ''unfolded'' Wilson chain, which brings about a significant reduction in numerical costs compared to those of NRG. We show that all NRG eigenstates (kept and discarded) can be reproduced using VMPS, and compare the difference in truncation criteria, sharp vs. smooth in energy space, of the two approaches. Finally, we demonstrate that NRG results can be improved upon systematically by performing a variational optimization in the space of variational matrix-product states, using the states produced by NRG as input. In the second project we demonstrate how the matrix-product state formalism provides a flexible structure to solve the constrained optimization problem associated with the sequential generation of entangled multiqubit states under experimental restrictions. We consider a realistic scenario in which an ancillary system with a limited number of levels performs restricted sequential interactions with qubits in a row. The proposed method relies on a suitable local optimization procedure, yielding an efficient recipe for the realistic and approximate sequential generation of any entangled multiqubit state. We give
Matrix-product states for strongly correlated systems and quantum information processing
Energy Technology Data Exchange (ETDEWEB)
Saberi, Hamed
2008-12-12
This thesis offers new developments in matrix-product state theory for studying the strongly correlated systems and quantum information processing through three major projects: In the first project, we perform a systematic comparison between Wilson's numerical renormalization group (NRG) and White's density-matrix renormalization group (DMRG). The NRG method for solving quantum impurity models yields a set of energy eigenstates that have the form of matrix-product states (MPS). White's DMRG for treating quantum lattice problems can likewise be reformulated in terms of MPS. Thus, the latter constitute a common algebraic structure for both approaches. We exploit this fact to compare the NRG approach for the single-impurity Anderson model to a variational matrix-product state approach (VMPS), equivalent to single-site DMRG. For the latter, we use an ''unfolded'' Wilson chain, which brings about a significant reduction in numerical costs compared to those of NRG. We show that all NRG eigenstates (kept and discarded) can be reproduced using VMPS, and compare the difference in truncation criteria, sharp vs. smooth in energy space, of the two approaches. Finally, we demonstrate that NRG results can be improved upon systematically by performing a variational optimization in the space of variational matrix-product states, using the states produced by NRG as input. In the second project we demonstrate how the matrix-product state formalism provides a flexible structure to solve the constrained optimization problem associated with the sequential generation of entangled multiqubit states under experimental restrictions. We consider a realistic scenario in which an ancillary system with a limited number of levels performs restricted sequential interactions with qubits in a row. The proposed method relies on a suitable local optimization procedure, yielding an efficient recipe for the realistic and approximate sequential generation of any
Energy Technology Data Exchange (ETDEWEB)
Hehn, Anna-Sophia; Holzer, Christof; Klopper, Wim, E-mail: klopper@kit.edu
2016-11-10
Highlights: • Ring-coupled-cluster-doubles approach now implemented with exchange terms. • Ring-coupled-cluster-doubles approach now implemented with F12 functions. • Szabo–Ostlund scheme (SO2) implemented for use in SAPT. • Fast convergence to the limit of a complete basis. • Implementation in the TURBOMOLE program system. - Abstract: Random-phase-approximation (RPA) methods have proven to be powerful tools in electronic-structure theory, being non-empirical, computationally efficient and broadly applicable to a variety of molecular systems including small-gap systems, transition-metal compounds and dispersion-dominated complexes. Applications are however hindered due to the slow basis-set convergence of the electron-correlation energy with the one-electron basis. As a remedy, we present approximate explicitly-correlated RPA approaches based on the ring-coupled-cluster-doubles formulation including exchange contributions. Test calculations demonstrate that the basis-set convergence of correlation energies is drastically accelerated through the explicitly-correlated approach, reaching 99% of the basis-set limit with triple-zeta basis sets. When implemented in close analogy to early work by Szabo and Ostlund [36], the new explicitly-correlated ring-coupled-cluster-doubles approach including exchange has the perspective to become a valuable tool in the framework of symmetry-adapted perturbation theory (SAPT) for the computation of dispersion energies of molecular complexes of weakly interacting closed-shell systems.
Directory of Open Access Journals (Sweden)
Yange Shao
2014-01-01
Full Text Available The phenomenon of stochastic synchronization in globally coupled FitzHugh-Nagumo (FHN neuron system subjected to spatially correlated Gaussian noise is investigated based on dynamical mean-field approximation (DMA and direct simulation (DS. Results from DMA are in good quantitative or qualitative agreement with those from DS for weak noise intensity and larger system size. Whether the consisting single FHN neuron is staying at the resting state, subthreshold oscillatory regime, or the spiking state, our investigation shows that the synchronization ratio of the globally coupled system becomes higher as the noise correlation coefficient increases, and thus we conclude that spatial correlation has an active effect on stochastic synchronization, and the neurons can achieve complete synchronization in the sense of statistics when the noise correlation coefficient tends to one. Our investigation also discloses that the noise spatial correlation plays the same beneficial role as the global coupling strength in enhancing stochastic synchronization in the ensemble. The result might be useful in understanding the information coding mechanism in neural systems.
Directory of Open Access Journals (Sweden)
M. Gianfreda
2012-01-01
Full Text Available We discuss conditions giving rise to stationary position-momentum correlations among quantum states in the Fock and coherent basis associated with the natural invariant for the one-dimensional time-dependent quadratic Hamiltonian operators such as the Kanai-Caldirola Hamiltonian. We also discuss some basic features such as quantum decoherence of the wave functions resulting from the corresponding quantum dynamics of these systems that exhibit no timedependence in their quantum correlations. In particular, steady statistical momentum averages are seen over well-defined time intervals in the evolution of a linear superposition of the basis states of modified exponentially damped mass systems.
International Nuclear Information System (INIS)
Zhang Xiu-Xing; Li Fu-Li
2011-01-01
The correlation dynamics are investigated for various bi-partitions of a composite quantum system consisting of two qubits and two independent and non-identical noisy environments. The two qubits have no direct interaction with each other and locally interact with their environments. Classical and quantum correlations including the entanglement are initially prepared only between the two qubits. We find that contrary to the identical noisy environment case, the quantum correlation transfer direction can be controlled by combining different noisy environments. The amplitude-damping environment determines whether there exists the entanglement transfer among bi-partitions of the system. When one qubit is coupled to an amplitude-damping environment and the other one to a bit-flip one, we find a very interesting result that all the quantum and the classical correlations, and even the entanglement, originally existing between the qubits, can be completely transferred without any loss to the qubit coupled to the bit-flit environment and the amplitude-damping environment. We also notice that it is possible to distinguish the quantum correlation from the classical correlation and the entanglement by combining different noisy environments. (general)
Ma, Jing; Fu, Yulong; Tan, Liying; Yu, Siyuan; Xie, Xiaolong
2018-05-01
Spatial diversity as an effective technique to mitigate the turbulence fading has been widely utilized in free space optical (FSO) communication systems. The received signals, however, will suffer from channel correlation due to insufficient spacing between component antennas. In this paper, the new expressions of the channel correlation coefficient and specifically its components (the large- and small-scale channel correlation coefficients) for a plane wave with aperture effects are derived for horizontal link in moderate-to-strong turbulence, using a non-Kolmogorov spectrum that has a generalized power law in the range of 3-4 instead of the fixed classical Kolmogorov power law of 11/3. And then the influence of power law variations on the channel correlation coefficient and its components are analysed. The numerical results indicated that various value of the power law lead to varying effects on the channel correlation coefficient and its components. This work will help with the further investigation on the fading correlation in spatial diversity systems.
Wijaya, Linda K; Kasjmir, Yoga Iwanoff; Sukmana, Nanang; Subekti, Imam; Prihartono, Joedo
2005-01-01
To understand the proportion of dyslipidemia in systemic lupus erythematosus (SLE) patients and the influencing factors of dyslipidemia. AN observational, cross-sectional study was conducted on new and longstanding SLE patients who had been diagnosed based on ARA criteria 1982 with 1997 revision. They had been hospitalized and treated at Department of Internal Medicine, Cipto Mangunkusumo National Central General Hospital and the other private Hospitals in Jakarta, i.e. Kramat Hospital in July - November 2003. The sample was selected by non probability sampling method with consecutive sampling technique. Every participant underwent history taking, physical and laboratory examination. There were 77 patients satisfying the inclusion criteria. The proportion of dyslipidemia in this study was 75.3%. By confidence interval of 95%, the dyslipidemia in SLE patient was 65.3% - 84.6%. The distribution of lipid profile in sample population were 43% with total cholesterol > or = 200 mg/dL, 26% with HDL cholesterol level or = 130 mg/dl and 44.2% with triglycerides serum level > or = 150 mg/dL. The characteristics of influencing factors in dyslipidemia prevalence for sample population consisted of 24.7% with renal involvement, 53.2% with > or = 3 years illness periods, 26% had received > or = 30 mg/day prednisone, 94.8% had not received chloroquines, and 58.4% had illness activity of Mex-SLEDAI > or = 2. By bivariate analysis, we found that illness period dyslipedemia prevalence. Prednisone > or = 30 mg/dL is the correlative factor for total cholesterol > or = 200 mg.dL and triglycerides > or = 150 mg/dL. Mex-SLEDAI > or = 2 is the corrective factor for HDL cholesterol < 40 mg/dL.
Quantum criticality around metal-insulator transitions of strongly correlated electron systems
Misawa, Takahiro; Imada, Masatoshi
2007-03-01
Quantum criticality of metal-insulator transitions in correlated electron systems is shown to belong to an unconventional universality class with violation of the Ginzburg-Landau-Wilson (GLW) scheme formulated for symmetry breaking transitions. This unconventionality arises from an emergent character of the quantum critical point, which appears at the marginal point between the Ising-type symmetry breaking at nonzero temperatures and the topological transition of the Fermi surface at zero temperature. We show that Hartree-Fock approximations of an extended Hubbard model on square lattices are capable of such metal-insulator transitions with unusual criticality under a preexisting symmetry breaking. The obtained universality is consistent with the scaling theory formulated for Mott transitions and with a number of numerical results beyond the mean-field level, implying that preexisting symmetry breaking is not necessarily required for the emergence of this unconventional universality. Examinations of fluctuation effects indicate that the obtained critical exponents remain essentially exact beyond the mean-field level. It further clarifies the whole structure of singularities by a unified treatment of the bandwidth-control and filling-control transitions. Detailed analyses of the criticality, containing diverging carrier density fluctuations around the marginal quantum critical point, are presented from microscopic calculations and reveal the nature as quantum critical “opalescence.” The mechanism of emerging marginal quantum critical point is ascribed to a positive feedback and interplay between the preexisting gap formation present even in metals and kinetic energy gain (loss) of the metallic carrier. Analyses of crossovers between GLW type at nonzero temperature and topological type at zero temperature show that the critical exponents observed in (V,Cr)2O3 and κ-ET -type organic conductors provide us with evidence for the existence of the present marginal
International Nuclear Information System (INIS)
Gong, Longyan; Zhu, Hao; Zhao, Shengmei; Cheng, Weiwen; Sheng, Yubo
2012-01-01
We investigate numerically the quantum discord and the classical correlation in a one-dimensional slowly varying potential model and a one-dimensional Soukoulis–Economou ones, respectively. There are well-defined mobility edges in the slowly varying potential model, while there are discrepancies on mobility edges in the Soukoulis–Economou ones. In the slowly varying potential model, we find that extended and localized states can be distinguished by both the quantum discord and the classical correlation. There are sharp transitions in the quantum discord and the classical correlation at mobility edges. Based on these, we study “mobility edges” in the Soukoulis–Economou model using the quantum discord and the classical correlation, which gives another perspectives for these “mobility edges”. All these provide us good quantities, i.e., the quantum discord and the classical correlation, to reflect mobility edges in these one-dimensional aperiodic single-electron systems. Moreover, our studies propose a consistent interpretation of the discrepancies between previous numerical results about the Soukoulis–Economou model. -- Highlights: ► Quantum discord and classical correlation can signal mobility edges in two models. ► An interpretation for mobility edges in the Soukoulis–Economou model is proposed. ► Quantum discord and classical correlation can reflect well localization properties.
Spin-Projected Matrix Product States: Versatile Tool for Strongly Correlated Systems.
Li, Zhendong; Chan, Garnet Kin-Lic
2017-06-13
We present a new wave function ansatz that combines the strengths of spin projection with the language of matrix product states (MPS) and matrix product operators (MPO) as used in the density matrix renormalization group (DMRG). Specifically, spin-projected matrix product states (SP-MPS) are constructed as [Formula: see text], where [Formula: see text] is the spin projector for total spin S and |Ψ MPS (N,M) ⟩ is an MPS wave function with a given particle number N and spin projection M. This new ansatz possesses several attractive features: (1) It provides a much simpler route to achieve spin adaptation (i.e., to create eigenfunctions of Ŝ 2 ) compared to explicitly incorporating the non-Abelian SU(2) symmetry into the MPS. In particular, since the underlying state |Ψ MPS (N,M) ⟩ in the SP-MPS uses only Abelian symmetries, one does not need the singlet embedding scheme for nonsinglet states, as normally employed in spin-adapted DMRG, to achieve a single consistent variationally optimized state. (2) Due to the use of |Ψ MPS (N,M) ⟩ as its underlying state, the SP-MPS can be closely connected to broken-symmetry mean-field states. This allows one to straightforwardly generate the large number of broken-symmetry guesses needed to explore complex electronic landscapes in magnetic systems. Further, this connection can be exploited in the future development of quantum embedding theories for open-shell systems. (3) The sum of MPOs representation for the Hamiltonian and spin projector [Formula: see text] naturally leads to an embarrassingly parallel algorithm for computing expectation values and optimizing SP-MPS. (4) Optimizing SP-MPS belongs to the variation-after-projection (VAP) class of spin-projected theories. Unlike usual spin-projected theories based on determinants, the SP-MPS ansatz can be made essentially exact simply by increasing the bond dimensions in |Ψ MPS (N,M) ⟩. Computing excited states is also simple by imposing orthogonality constraints
Spatial and temporal correlation in dynamic, multi-electron quantum systems
Energy Technology Data Exchange (ETDEWEB)
Godunov, A.L.; McGuire, J.H.; Shakov, Kh.Kh. [Department of Physics, Tulane University, New Orleans, LA (United States); Ivanov, P.B.; Shipakov, V.A. [Troitsk Institute for Innovation and Fusion Research, Troitsk (Russian Federation); Merabet, H.; Bruch, R.; Hanni, J. [Department of Physics, University of Nevada Reno, Reno, NV (United States)
2001-12-28
Cross sections for ionization with excitation and for double excitation in helium are evaluated in a full second Born calculation. These full second Born calculations are compared to calculations in the independent electron approximation, where spatial correlation between the electrons is removed. Comparison is also made to calculations in the independent time approximation, where time correlation between the electrons is removed. The two-electron transitions considered here are caused by interactions with incident protons and electrons with velocities ranging between 2 and 10 au. Good agreement is found between our full calculations and experiment, except for the lowest velocities, where higher Born terms are expected to be significant. Spatial electron correlation, arising from internal electron-electron interactions, and time correlation, arising from time ordering of the external interactions, can both give rise to observable effects. Our method may be used for photon impact. (author)
Energy Technology Data Exchange (ETDEWEB)
Grotti, Marco, E-mail: grotti@chimica.unige.i [Dipartimento di Chimica e Chimica Industriale, Via Dodecaneso 31, 16146 Genova (Italy); Todoli, Jose Luis [Departamento de Quimica Analitica, Nutricion y Bromatologia, Universidad de Alicante, 03080, Alicante (Spain); Mermet, Jean Michel [Spectroscopy Forever, 01390 Tramoyes (France)
2010-02-15
The influence of the acquisition and operating parameters on time correlation between emission line intensities was investigated using axially viewed inductively coupled plasma-multichannel-based emission spectrometry and various sample introduction systems. It was found that to obtain flicker-noise limited signals, necessary to compensate for time-correlated signal fluctuations by internal standardization, the flicker-noise magnitude of the sample introduction system, the integration time and the emission line intensity had to be considered. The highest correlation between lines was observed for ultrasonic nebulization with desolvatation, the noisiest system among those considered, for which the contribution of the uncorrelated shot-noise was negligible. In contrast, for sample introduction systems characterized by lower flicker-noise levels, shot-noise led to high, non-correlated RSD values, making the internal standard method to be much less efficient. To minimize shot-noise, time correlation was improved by increasing the emission line intensities and the integration time. Improvement in repeatability did not depend only on time correlation, but also on the ratio between the relative standard deviations of the analytical and reference lines. The best signal compensation was obtained when RSD values of the reference and analytical lines were similar, which is usually obtained when the system is flicker-noise limited, while departure from similarity can lead to a degradation of repeatability when using the internal standard method. Moreover, the use of so-called robust plasma conditions, i.e. a high power (1500 W) along with a low carrier gas flow rate (0.8 L/min) improved also the compensation. Finally, high correlation and consequent improvement in repeatability by internal standardization was observed also in the presence of complex matrices (sediment and soil samples), although a matrix-induced degradation of the correlation between lines was generally
Directory of Open Access Journals (Sweden)
Zhixian Huang
Full Text Available Abstract To investigate the mass transfer behavior of a liquid-liquid system with high density difference (∆ρ≈500 kg/m3, single drop experiments were performed by using the ternary chloroform-ethanol-water system. The mass transfer direction was from the dispersed phase to the continuous phase, while the aqueous phase was dispersed in chloroform to generate drops. The influences of drop diameter, initial solute concentration and temperature on the mass transfer were investigated. The effects of the drop diameter and initial solute concentration on interfacial instability of droplets hanging in the continuous phase were also observed. For the purpose of correlation, a mass transfer enhancement factor F was introduced and then correlated as a function of dimensionless variables. The modified correlation from the mass transfer coefficient model was found to fit well with the experimental values.
Directory of Open Access Journals (Sweden)
V. V. Hryhorovskyi
2015-04-01
Full Text Available Actuality. The correlation analysis between various indices of bone tissue condition was not previously carried out in patients with osteogenesis imperfecta. Aim. On purpose to determine differences and index correlations before and after intake of pamidronate systemic therapy in 13 patients with osteogenesis imperfecta indices of some methods including histomorphometric were studied. Results. We found correlation parametres of biochemical indices, on one side and histomorphometric – on the other. Conclusion. After systemic therapy mean parametres of «bone volume» in iliobiopsies increase, and «osteoid surface» and «osteoclast index per surface unit» in patients with osteogenesis imperfecta of I type – decrease, that one can regard as a tendency to improvement of the bone tissue structural-functional condition.
Directory of Open Access Journals (Sweden)
Dea Diella
2017-11-01
Full Text Available The aims of this study is to reveal metacognition and critical thinking skill of students grade XI, and also the correlation between metacognition with crititical thinking skill on human excretion system. The participants of this study consist of 100 students from grade XI of five different high schools in Tasikmalaya. Correlational method was used in this study. Instruments which used to obtain the data consist of metacognition test and critical thinking test. The students' metacognition was captured with the essay item related to the human excretion system concept. The multiple choice-reason item and essay item was used to capture the critical thinking skills. The results showed that students’ score at metacognition and critical thinking have a low average. The results also proved that metacognition has a positive correlation and moderately strong with critical thinking skills
Local Magnetism in Strongly Correlated Electron Systems with Orbital Degrees of Freedom
Ducatman, Samuel Charles
The central aim of my research is to explain the connection between the macroscopic behavior and the microscopic physics of strongly correlated electron systems with orbital degrees of freedom through the use of effective models. My dissertation focuses on the sub-class of these materials where electrons appear to be localized by interactions, and magnetic ions have well measured magnetic moments. This suggests that we can capture the low-energy physics of the material by employing a minimal model featuring localized spins which interact with each other through exchange couplings. I describe Fe1+y Te and beta-Li2IrO3 with effective models primarily focusing on the spins of the magnetic ions, in this case Fe and Ir, respectively. The goal with both materials is to gain insight and make predictions for experimentalists. In chapter 2, I focus on Fe1+yTe. I describe why we believe the magnetic ground state of this material, with an observed Bragg peak at Q +/- pi/2, pi/2), can be described by a Heisenberg model with 1st, 2nd, and 3rd neighbor interactions. I present two possible ground states of this model in the small J1 limit, the bicollinear and plaquette states. In order to predict which ground state the model prefers, I calculate the spin wave spectrum with 1/S corrections, and I find the model naturally selects the "plaquette state." I give a brief description of the ways this result could be tested using experimental techniques such as polarized neutron scattering. In chapter 3, I extend the model used in chapter 2. This is necessary because the Heisenberg model we employed cannot explain why Fe1+yTe undergoes a phase transition as y is increased. We add an additional elements to our calculation; we assume that electrons in some of the Fe 3D orbitals have selectively localized while others remain itinerant. We write a new Hamiltonian, where localized moments acquire a new long-range RKKY-like interaction from interactions with the itinerant electrons. We are
Wapenaar, C.P.A.; Fokkema, J.; Snieder, R.
2005-01-01
We compare two approaches for deriving the fact that the Green’s function in an arbitrary inhomogeneous open system can be obtained by cross correlating recordings of the wave field at two positions. One approach is based on physical arguments, exploiting the principle of time-reversal invariance of
Arthur, Tsamouo Tsokeng; Martin, Tchoffo; Fai, Lukong Cornelius
2018-06-01
We investigate the dynamics of entanglement, decoherence and quantum discord in a system of three non-interacting superconducting flux qubits (fqubits) initially prepared in a Greenberger-Horne-Zeilinger (GHZ) state and subject to static noise in different, bipartite and common environments, since it is recognized that different noise configurations generally lead to completely different dynamical behavior of physical systems. The noise is modeled by randomizing the single fqubit transition amplitude. Decoherence and quantum correlations dynamics are strongly affected by the purity of the initial state, type of system-environment interaction and the system-environment coupling strength. Specifically, quantum correlations can persist when the fqubits are commonly coupled to a noise source, and reaches a saturation value respective to the purity of the initial state. As the number of decoherence channels increases (bipartite and different environments), decoherence becomes stronger against quantum correlations that decay faster, exhibiting sudden death and revival phenomena. The residual entanglement can be successfully detected by means of suitable entanglement witness, and we derive a necessary condition for entanglement detection related to the tunable and non-degenerated energy levels of fqubits. In accordance with the current literature, our results further suggest the efficiency of fqubits over ordinary ones, as far as the preservation of quantum correlations needed for quantum processing purposes is concerned.
International Nuclear Information System (INIS)
Brown, G.; Moore, P.G.F.; Richmond, R.
1963-01-01
The results are given of exponential experiments on graphite moderated systems with fuel elements consisting of single rods and tubes of natural uranium metal. A correlation is given with the method of calculation proposed by Syrett (1961) and new consistent values of neutron yield and effective resonance integral are derived. (author)
Alavi, Hamid Reza; Rahimipoor, Tahereh
2010-01-01
The goal of this research was to understand the managers' value system, the students' moral development, and their relationship in the high schools and pre-universities of District One in Kerman City. The research method used was descriptive-correlational. The statistical population was composed of high school and pre-university managers and…
Compagnone, Eliana; Maniglio, Jlenia; Camposeo, Serena; Vespino, Teresa; Losito, Luciana; De Rinaldis, Marta; Gennaro, Leonarda; Trabacca, Antonio
2014-11-01
This study aimed to investigate a possible correlation between the gross motor function classification system-expanded and revised (GMFCS-E&R), the manual abilities classification system (MACS) and the communication function classification system (CFCS) functional levels in children with cerebral palsy (CP) by CP subtype. It was also geared to verify whether there is a correlation between these classification systems and intellectual functioning (IF) and parental socio-economic status (SES). A total of 87 children (47 males and 40 females, age range 4-18 years, mean age 8.9±4.2) were included in the study. A strong correlation was found between the three classifications: Level V of the GMFCS-E&R corresponds to Level V of the MACS (rs=0.67, p=0.001); the same relationship was found for the CFCS and the MACS (rs=0.73, p<0.001) and for the GMFCS-E&R and the CFCS (rs=0.61, p=0.001). The correlations between the IQ and the global functional disability profile were strong or moderate (GMFCS and IQ: rs=0.66, p=0.001; MACS and IQ: rs=0.58, p=0.001; CFCS and MACS: rs=0.65, p=0.001). The Kruskal-Wallis test was used to determine if there were differences between the GMFCS-E&R, the CFCS and the MACS by CP type. CP types showed different scores for the IQ level (Chi-square=8.59, df=2, p=0.014), the GMFCS-E&R (Chi-square=36.46, df=2, p<0.001), the CFCS (Chi-square=12.87, df=2, p=0.002), and the MACS Level (Chi-square=13.96, df=2, p<0.001) but no significant differences emerged for the SES (Chi-square=1.19, df=2, p=0.554). This study shows how the three functional classifications (GMFCS-E&R, CFCS and MACS) complement each other to provide a better description of the functional profile of CP. The systematic evaluation of the IQ can provide useful information about a possible future outcome for every functional level. The SES does not appear to affect functional profiles. Copyright © 2014 Elsevier Ltd. All rights reserved.
Two- and multi-particle azimuthal correlations in small collision systems with the ATLAS detector
AUTHOR|(INSPIRE)INSPIRE-00256459; The ATLAS collaboration
2017-01-01
The recent ATLAS results on two- and multi-particle azimuthal correlations of charged particles are presented for $\\sqrt{s}$=~5.02 TeV and 13 TeV $pp$, $\\sqrt{s_\\mathrm{NN}}$= 5.02 TeV $p$+Pb and $\\sqrt{s_\\mathrm{NN}}$= 2.76 TeV low-multiplicity Pb+Pb collisions. To remove the "non-flow" contribution from the correlations, that arises predominantly from hard-scattering processes, a template fitting procedure is used in the two-particle correlations (2PC) measurements, while for multi-particle correlations the cumulant method is applied. The correlations are expressed in the form of Fourier harmonics $\\mathrm{v}_n (n=2,3,4)$ measuring the global azimuthal anisotropy. The measurements presented hereafter confirm the evidence for collective phenomena in $p$+Pb and low-multiplicity Pb+Pb collisions. For $pp$ collisions the results on four-particle cumulants do not demonstrate a similar collective behaviour.
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.
International Nuclear Information System (INIS)
Mayzelis, Z.A.; Apostolov, S.S.; Melnyk, S.S.; Usatenko, O.V.; Yampol'skii, V.A.
2007-01-01
A theory of symbolic dynamic systems with long-range correlations based on the consideration of the binary N-step Markov chains developed earlier in Phys Rev Lett 2003;90:110601 is generalized to the biased case (non-equal numbers of zeros and unities in the chain). In the model, the conditional probability that the ith symbol in the chain equals zero (or unity) is a linear function of the number of unities (zeros) among the preceding N symbols. The correlation and distribution functions as well as the variance of number of symbols in the words of arbitrary length L are obtained analytically and verified by numerical simulations. A self-similarity of the studied stochastic process is revealed and the similarity group transformation of the chain parameters is presented. The diffusion Fokker-Planck equation governing the distribution function of the L-words is explored. If the persistent correlations are not extremely strong, the distribution function is shown to be the Gaussian with the variance being nonlinearly dependent on L. An equation connecting the memory and correlation function of the additive Markov chain is presented. This equation allows reconstructing a memory function using a correlation function of the system. Effectiveness and robustness of the proposed method is demonstrated by simple model examples. Memory functions of concrete coarse-grained literary texts are found and their universal power-law behavior at long distances is revealed
Energy Technology Data Exchange (ETDEWEB)
Mayzelis, Z.A. [Department of Physics, Kharkov National University, 4 Svoboda Sq., Kharkov 61077 (Ukraine); Apostolov, S.S. [Department of Physics, Kharkov National University, 4 Svoboda Sq., Kharkov 61077 (Ukraine); Melnyk, S.S. [A. Ya. Usikov Institute for Radiophysics and Electronics, Ukrainian Academy of Science, 12 Proskura Street, 61085 Kharkov (Ukraine); Usatenko, O.V. [A. Ya. Usikov Institute for Radiophysics and Electronics, Ukrainian Academy of Science, 12 Proskura Street, 61085 Kharkov (Ukraine)]. E-mail: usatenko@ire.kharkov.ua; Yampol' skii, V.A. [A. Ya. Usikov Institute for Radiophysics and Electronics, Ukrainian Academy of Science, 12 Proskura Street, 61085 Kharkov (Ukraine)
2007-10-15
A theory of symbolic dynamic systems with long-range correlations based on the consideration of the binary N-step Markov chains developed earlier in Phys Rev Lett 2003;90:110601 is generalized to the biased case (non-equal numbers of zeros and unities in the chain). In the model, the conditional probability that the ith symbol in the chain equals zero (or unity) is a linear function of the number of unities (zeros) among the preceding N symbols. The correlation and distribution functions as well as the variance of number of symbols in the words of arbitrary length L are obtained analytically and verified by numerical simulations. A self-similarity of the studied stochastic process is revealed and the similarity group transformation of the chain parameters is presented. The diffusion Fokker-Planck equation governing the distribution function of the L-words is explored. If the persistent correlations are not extremely strong, the distribution function is shown to be the Gaussian with the variance being nonlinearly dependent on L. An equation connecting the memory and correlation function of the additive Markov chain is presented. This equation allows reconstructing a memory function using a correlation function of the system. Effectiveness and robustness of the proposed method is demonstrated by simple model examples. Memory functions of concrete coarse-grained literary texts are found and their universal power-law behavior at long distances is revealed.
Total and Direct Correlation Function Integrals from Molecular Simulation of Binary Systems
DEFF Research Database (Denmark)
Wedberg, Nils Hejle Rasmus Ingemar; O’Connell, John P.; Peters, Günther H.J.
2011-01-01
The possibility for obtaining derivative properties for mixtures from integrals of spatial total and direct correlation functions obtained from molecular dynamics simulations is explored. Theoretically well-supported methods are examined to extend simulation radial distribution functions to long...... are consistent with an excess Helmholtz energy model fitted to available simulations. In addition, simulations of water/methanol and water/t-butanol mixtures have been carried out. The method yields results for partial molar volumes, activity coefficient derivatives, and individual correlation function integrals...... in reasonable agreement with smoothed experimental data. The proposed method for obtaining correlation function integrals is shown to perform at least as well as or better than two previously published approaches....
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.
Coulomb correlations in many-electron systems on the level of self-consistent fields
International Nuclear Information System (INIS)
Warken, M.
1991-06-01
It was the aim of this thesis to show means and ways, in order to regard Coulomb correlation already on the SCF level. As mean to facilitate this general averaged fields should serve. For this first in chapter I was shown, how by means of suitable gauge fixings terms into effective potentials of the Hartree-Fock or g-Hartree type are introduced, which permit an interpretation as correlation density or as effective coupling constant. The following considerations were exemplarily performed on the cases g-Hartree (in Coulomb gauge) and on f-Hartree-Fock. (orig./HSI) [de
Morgan, Christopher G.; Mitchell, A. C.; Murray, J. G.
1990-05-01
An imaging photon detector has been modified to incorporate fast timing electronics coupled to a custom built photon correlator interfaced to a RISC computer. Using excitation with intensity- muodulated light, fluorescence images can be readily obtained where contrast is determined by the decay time of emission, rather than by intensity. This technology is readily extended to multifrequency phase/demodulation fluorescence imaging or to differential polarised phase fluorometry. The potential use of the correlator for confocal imaging with a laser scanner is also briefly discussed.
Directory of Open Access Journals (Sweden)
Sajjad Alizadeh
2014-04-01
Full Text Available Conventional Time Reversal (TR technique suffers from performance degradation in time varying Multiple-Input Multiple-Output Ultra-Wideband (MIMO-UWB systems due to outdating Channel State Information (CSI over time progressions. That is, the outdated CSI degrades the TR performance significantly in time varying channels. The correlation property of time correlated channels can improve the TR performance against other traditional TR designs. Based on this property, at first, we propose a robust TR-MIMO-UWB system design for a time-varying channel in which the CSI is updated only at the beginning of each block of data where the CSI is assumed to be known. As the channel varies over time, pre-processor blindly pre-equalizes the channel during the next symbol time by using the correlation property. Then, a novel recursive power allocation strategy is derived over time-correlated time-varying TR-MIMO-UWB channels. We show that the proposed power loading technique, considerably improves the BER performance of TR-MIMO-UWB system in imperfect CSI with robust pre-filter. The proposed algorithms lead to a cost-efficient CSI updating procedure for the TR optimization. Simulation results are provided to confirm the new design performance against traditional method.
DEFF Research Database (Denmark)
Shah, Louise Jivan; Furbo, Simon
1998-01-01
-calculations are used to carry out a detailed analysis of the heat transfer from the solar collector fluid to the wall of the inner tank. The analysis has resulted in a local Nusselt-Rayleigh correlation for the heat transfer between the solar collector fluid and the wall of the inner tank....
Electron correlation influenced magnetic phase transitions in f-electron systems
International Nuclear Information System (INIS)
Frauenheim, T.; Ropke, G.
1980-01-01
The temperature-induced phase transition (on lowering the temperature) antiferromagnet-ferromagnet in the heavy rare earth and some of actinide compounds is qualitatively explained in the scope of a two-band Hubbard model and the more complex RKKY model as the result of electron correlation effects in the conduction bands. (orig.)
How Correlated is the FeSe /SrTiO3 System?
Mandal, Subhasish; Zhang, Peng; Ismail-Beigi, Sohrab; Haule, K.
2017-08-01
Recent observation of ˜10 times higher critical temperature in a FeSe monolayer compared with its bulk phase has drawn a great deal of attention because the electronic structure in the monolayer phase appears to be different than bulk FeSe. Using a combination of density functional theory and dynamical mean field theory, we find electronic correlations have important effects on the predicted atomic-scale geometry and the electronic structure of the monolayer FeSe on SrTiO3 . The electronic correlations are dominantly controlled by the Se-Fe-Se angle either in the bulk phase or the monolayer phase. But the angle sensitivity increases and the orbital differentiation decreases in the monolayer phase compared to the bulk phase. The correlations are more dependent on Hund's J than Hubbard U . The observed orbital selective incoherence to coherence crossover with temperature confirms the Hund's metallic nature of the monolayer FeSe. We also find electron doping by oxygen vacancies in SrTiO3 increases the correlation strength, especially in the dx y orbital by reducing the Se-Fe-Se angle.
Chosen-plaintext attack on a joint transform correlator encrypting system
Barrera, John Fredy; Vargas, Carlos; Tebaldi, Myrian; Torroba, Roberto
2010-10-01
We demonstrate that optical encryption methods based on the joint transform correlator architecture are vulnerable to chosen-plaintext attack. An unauthorized user, who introduces three chosen plaintexts in the accessible encryption machine, can obtain the security key code mask. In this contribution, we also propose an alternative method to eliminate ambiguities that allows obtaining the right decrypting key.
DEFF Research Database (Denmark)
Wuttge, D. M.; Carlsen, A. L.; Teku, G.
2015-01-01
Objective. To evaluate the expression profiles of cell-free plasma miRNAs in SSc and to characterize their correlation with disease subgroups (lcSSc and dcSSc) and with autoantibody profiles. Methods. Using quantitative RT-PCR, the abundance of 45 mature miRNAs in plasma was determined in 95 pati...
van Loon, A.M.
2014-01-01
How and where does our brain integrated the information that we get into our eyes into a unifying percept and into a conscious experience? Although different neural correlates of consciousness (NCC) have been proposed, depending on the kind of neural signals recorded, the type of manipulation used,
Lu, Feng; Liu, Kang; Duan, Yingying; Cheng, Shifen; Du, Fei
2018-07-01
A better characterization of the traffic influence among urban roads is crucial for traffic control and traffic forecasting. The existence of spatial heterogeneity imposes great influence on modeling the extent and degree of road traffic correlation, which is usually neglected by the traditional distance based method. In this paper, we propose a traffic-enhanced community detection approach to spatially reveal the traffic correlation in city road networks. First, the road network is modeled as a traffic-enhanced dual graph with the closeness between two road segments determined not only by their topological connection, but also by the traffic correlation between them. Then a flow-based community detection algorithm called Infomap is utilized to identify the road segment clusters. Evaluated by Moran's I, Calinski-Harabaz Index and the traffic interpolation application, we find that compared to the distance based method and the community based method, our proposed traffic-enhanced community based method behaves better in capturing the extent of traffic relevance as both the topological structure of the road network and the traffic correlations among urban roads are considered. It can be used in more traffic-related applications, such as traffic forecasting, traffic control and guidance.
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, pchest 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.
Error analysis of supercritical water correlations using ATHLET system code under DHT conditions
Energy Technology Data Exchange (ETDEWEB)
Samuel, J., E-mail: jeffrey.samuel@uoit.ca [Univ. of Ontario Inst. of Tech., Oshawa, ON (Canada)
2014-07-01
The thermal-hydraulic computer code ATHLET (Analysis of THermal-hydraulics of LEaks and Transients) is used for analysis of anticipated and abnormal plant transients, including safety analysis of Light Water Reactors (LWRs) and Russian Graphite-Moderated High Power Channel-type Reactors (RBMKs). The range of applicability of ATHLET has been extended to supercritical water by updating the fluid-and transport-properties packages, thus enabling the code to the used in analysis of SuperCritical Water-cooled Reactors (SCWRs). Several well-known heat-transfer correlations for supercritical fluids were added to the ATHLET code and a numerical model was created to represent an experimental test section. In this work, the error in the Heat Transfer Coefficient (HTC) calculation by the ATHLET model is studied along with the ability of the various correlations to predict different heat transfer regimes. (author)
Relative ordering of square-norm distance correlations in open quantum systems
International Nuclear Information System (INIS)
Wu Tao; Song Xue-Ke; Ye Liu
2014-01-01
We investigate the square-norm distance correlation dynamics of the Bell-diagonal states under different local decoherence channels, including phase flip, bit flip, and bit-phase flip channels by employing the geometric discord (GD) and its modified geometric discord (MGD), as the measures of the square-norm distance correlations. Moreover, an explicit comparison between them is made in detail. The results show that there is no distinct dominant relative ordering between them. Furthermore, we obtain that the GD just gradually deceases to zero, while MGD initially has a large freezing interval, and then suddenly changes in evolution. The longer the freezing interval, the less the MGD is. Interestingly, it is shown that the dynamic behaviors of the two geometric discords under the three noisy environments for the Werner-type initial states are the same. (general)
van Soldt, Benjamin J; Danielsen, Carl Christian; Wang, Tobias
2015-12-01
Pythons are unique amongst snakes in having different pressures in the aortas and pulmonary arteries because of intraventricular pressure separation. In this study, we investigate whether this correlates with different blood vessel strength in the ball python Python regius. We excised segments from the left, right, and dorsal aortas, and from the two pulmonary arteries. These were subjected to tensile testing. We show that the aortic vessel wall is significantly stronger than the pulmonary artery wall in P. regius. Gross morphological characteristics (vessel wall thickness and correlated absolute amount of collagen content) are likely the most influential factors. Collagen fiber thickness and orientation are likely to have an effect, though the effect of collagen fiber type and cross-links between fibers will need further study. © 2015 Wiley Periodicals, Inc.
Reply to ``Comment on `Cluster methods for strongly correlated electron systems' ''
Biroli, G.; Kotliar, G.
2005-01-01
We reply to the Comment by Aryanpour, Maier, and Jarrell [Phys. Rev. B 71, 037101 (2005)] on our paper [Phys. Rev. B 65, 155112 (2002)]. We demonstrate, using general arguments and explicit examples, that whenever the correlation length is finite, local observables converge exponentially fast in the cluster size Lc within cellular dynamical mean field theory. This is a faster rate of convergence than the 1/ L2c behavior of the dynamical cluster approximation, thus refuting the central assertion of their Comment.
Oxygen optodes as fast sensors for eddy correlation measurements in aquatic systems
DEFF Research Database (Denmark)
Chipman, Lindsay; Huettel, Markus; Berg, Peter
2012-01-01
The aquatic eddy-correlation technique can be used to noninvasively determine the oxygen exchange across the sediment-water interface by analyzing the covariance of vertical flow velocity and oxygen concentration in a small measuring volume above the sea bed. The method requires fast sensors...... that combine the advantages of noninvasive measurements and integration of fluxes over a large footprint area, using a relatively rugged and less expensive sensor....
On correlation comparison of identical pions in different systems of reference
International Nuclear Information System (INIS)
Podgoretskij, M.I.
1983-01-01
It is shown that a comparison of correlations of identical pions in reference frames moving with different velocities along the reaction axis enables one to select the frame for which there is a kinematical symmetry in the multiple generation process. The indicated possibility is due to the fact that in the considered symmetrical frame the space-time parameters R and tau are extremal. An experimental selection of the ''symmetrical frame'' may be useful in the choice between competing models of multiple generation
Correlations in quantum systems and branch points in the complex plane
Rotter, I.
2001-01-01
Branch points in the complex plane are responsible for avoided level crossings in closed and open quantum systems. They create not only an exchange of the wave functions but also a mixing of the states of a quantum system at high level density. The influence of branch points in the complex plane on the low-lying states of the system is small.
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 0.7, 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.
Energy Technology Data Exchange (ETDEWEB)
Blanchette, C D; Woo, Y; Thomas, C; Shen, N; Sulchek, T A; Hiddessen, A L
2008-12-22
Phagocytosis has been extensively examined in 'professional' phagocytic cells using pH sensitive dyes. However, in many of the previous studies, a separation between the end of internalization, beginning of acidification and completion of phagosomal-endosomal/lysosomal fusion was not clearly established, and in several cases, it was treated as a one-step process. In addition, very little work has been done to systematically examine phagosomal maturation in 'non-professional' phagocytic cells, such as epithelial cells. Therefore, in this study, we developed a simple and novel method to decouple and accurately measure particle internalization, phagosomal acidification and phagosomal-endosomal/lysosomal fusion in Madin-Darby Canine Kidney (MDCK) and Caco-2 epithelial cells. Our method was developed using a pathogen mimetic system consisting of polystyrene beads coated with Internalin A (InlA), a membrane surface protein from Listeria monocytogenes known to trigger receptor-mediated internalization. We achieved independent measurements of the rates of internalization, phagosomal acidification and phagosomal-endosomal/lysosomal fusion in epithelial cells by combining the InlA-coated beads (InlA-beads) with antibody quenching, pH sensitive dyes and endosomal/lysosomal dyes, as follows: the rate of InlA bead internalization was measured via antibody quenching of a pH independent dye (Alexa488) conjugated to InlA-beads, the rate at which phagosomes containing internalized InlA beads became acidified was measured using a pH dependent dye (FITC) conjugated to the beads and the rate of phagosomal-endosomal/lysosomal fusion was measured using a combination of unlabeled InlA-beads and an endosomal/lysosomal dye. By performing these independent measurements under identical experimental conditions, we were able to decouple the three processes and establish time scales for each. In a separate set of experiments, we also exploited the phagosomal acidification
International Nuclear Information System (INIS)
Belandria, Veronica; Mohammadi, Amir H.; Richon, Dominique
2009-01-01
In this communication, we report experimental density data for the binary mixtures of (water + tetrahydrofuran) and (water + tetra-n-butyl ammonium bromide) at atmospheric pressure and various temperatures. The densities were measured using an Anton Paar TM digital vibrating-tube densimeter. For the (tetrahydrofuran + water) system, excess molar volumes have been calculated using the experimental densities and correlated using the Redlich-Kister equation. The Redlich-Kister equation parameters have been adjusted on experimental results. The partial molar volumes and partial excess molar volumes at infinite dilution have also been calculated for each component. A simple density equation was finally applied to correlate the measured density of the (tetra-n-butyl ammonium bromide + water) system.
Rispoli, Matthew; Lukin, Alexander; Ma, Ruichao; Preiss, Philipp; Tai, M. Eric; Islam, Rajibul; Greiner, Markus
2015-05-01
Ultracold atoms in optical lattices provide a versatile tool box for observing the emergence of strongly correlated physics in quantum systems. Dynamic control of optical potentials on the single-site level allows us to prepare and probe many-body quantum states through local Hamiltonian engineering. We achieve these high precision levels of optical control through spatial light modulation with a DMD (digital micro-mirror device). This allows for both arbitrary beam shaping and aberration compensation in our imaging system to produce high fidelity optical potentials. We use these techniques to control state initialization, Hamiltonian dynamics, and measurement in experiments investigating low-dimensional many-body physics - from one-dimensional correlated quantum walks to characterizing entanglement.
K.H. Awan
2016-01-01
Objective: E-cigarettes are becoming popular among youth as safe nicotine delivery systems. Many have expressed concern, however, that e-cigarettes may serve as a gateway to future smoking, given their low perceived risk, or that their use may prevent regular smokers from quitting by maintaining their nicotine addiction. The aim of this study was to assess experimentation with and correlates of e-cigarette use among university students. Material and methods: A cross-sectional study was car...
Wang, Rui; Tao, Meixia; Mehrpouyan, Hani; Hua, Yingbo
2014-01-01
In this paper, while considering the impact of antenna correlation and the interference from neighboring users, we analyze channel estimation and training sequence design for multi-input multi-output (MIMO) two-way relay (TWR) systems. To this end, we propose to decompose the bidirectional transmission links into two phases, i.e., the multiple access (MAC) phase and the broadcasting (BC) phase. By considering the Kronecker-structured channel model, we derive the optimal linear minimum mean-sq...
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.
CORRELATION OF EXPERIMENTAL AND THEORETICAL DATA FOR MANTLE TANKS USED IN LOW FLOW SDHW SYSTEMS
DEFF Research Database (Denmark)
Shah, Louise Jivan; Furbo, Simon
1997-01-01
-calculations, a detailed analysis of the heat transfer from the solar collector fluid to the wall of the hot water tank is performed. The analysis has resulted in a correlation for the heat transfer between the solar collector fluid and the wall of the hot water........1. The model is validated against the experimental tests, and good agreement between measured and calculated results is achieved. The results from the CFD-calculations are used to illustrate the thermal behaviour and the fluid dynamics in the mantle and in the hot water tank. With the CFD...
Correlations for the partition behavior of proteins in aqueous two-phase systems
DEFF Research Database (Denmark)
Schmidt, A.S.; Andrews, B.A.; Asenjo, J.A.
1996-01-01
to its high hydrophilicity. In the case of subtilisin and trypsin inhibitor, their high concentrations in the top phase were due to their hydrophobic nature (hydrophobic interaction with PEG) and small size (negligible steric exclusion). The maximum concentration in the bottom phase for trypsin inhibitor...... of the overall protein concentration, by the ratio between the ''saturation'' equations of the two individual phases. Better correlations were obtained when an empirical sigmoidal Boltzmann equation was fitted to the data, since in virtually all cases the partition coefficient is constant at low protein...
Bryant, N. A.; Zobrist, A. L.
1978-01-01
The paper describes the development of an image based information system and its use to process a Landsat thematic map showing land use or land cover in conjunction with a census tract polygon file to produce a tabulation of land use acreages per census tract. The system permits the efficient cross-tabulation of two or more geo-coded data sets, thereby setting the stage for the practical implementation of models of diffusion processes or cellular transformation. Characteristics of geographic information systems are considered, and functional requirements, such as data management, geocoding, image data management, and data analysis are discussed. The system is described, and the potentialities of its use are examined.
Directory of Open Access Journals (Sweden)
Cotae Paul
2004-01-01
Full Text Available An algorithm for designing spreading sequences for an overloaded multicellular synchronous DS-CDMA system on uplink is introduced. The criterion used to measure the optimality of the design is the total weighted square correlation (TWSC assuming the channel state information known perfectly at both transmitter and receiver. By using this algorithm it is possible to obtain orthogonal generalized WBE sequences sets for any processing gain. The bandwidth of initial generalized WBE signals of each cell is preserved in the extended signal space associated to multicellular system. Mathematical formalism is illustrated by selected numerical examples.
Impact of Non-Idealities System on Spatial Correlation in a Multi-Probe Based MIMO OTA Setup
DEFF Research Database (Denmark)
Fan, Wei; Nielsen, Jesper Ødum; Carreño, Xavier
2013-01-01
MIMO OTA testing methodologies are being intensively investigated by CTIA and 3GPP, where a multi-probe anechoic chamber based solution is an important candidate for future standardized testing. In this paper, the probes located on an OTA ring are used to reproduce the channel spatial information....... This paper investigates the extent to which we can emulate the channel spatial characteristics inside the test zone where the device under test is located. The focus is on performance deterioration introduced by system non-idealities on spatial correlation emulation in practical MIMO OTA test systems....
Kumar, Manoj; Vijayakumar, A; Rosen, Joseph
2017-09-14
We present a lensless, interferenceless incoherent digital holography technique based on the principle of coded aperture correlation holography. The acquired digital hologram by this technique contains a three-dimensional image of some observed scene. Light diffracted by a point object (pinhole) is modulated using a random-like coded phase mask (CPM) and the intensity pattern is recorded and composed as a point spread hologram (PSH). A library of PSHs is created using the same CPM by moving the pinhole to all possible axial locations. Intensity diffracted through the same CPM from an object placed within the axial limits of the PSH library is recorded by a digital camera. The recorded intensity this time is composed as the object hologram. The image of the object at any axial plane is reconstructed by cross-correlating the object hologram with the corresponding component of the PSH library. The reconstruction noise attached to the image is suppressed by various methods. The reconstruction results of multiplane and thick objects by this technique are compared with regular lens-based imaging.
Correlation of gene expression and protein production rate - a system wide study
Directory of Open Access Journals (Sweden)
Arvas Mikko
2011-12-01
Full Text Available Abstract Background Growth rate is a major determinant of intracellular function. However its effects can only be properly dissected with technically demanding chemostat cultivations in which it can be controlled. Recent work on Saccharomyces cerevisiae chemostat cultivations provided the first analysis on genome wide effects of growth rate. In this work we study the filamentous fungus Trichoderma reesei (Hypocrea jecorina that is an industrial protein production host known for its exceptional protein secretion capability. Interestingly, it exhibits a low growth rate protein production phenotype. Results We have used transcriptomics and proteomics to study the effect of growth rate and cell density on protein production in chemostat cultivations of T. reesei. Use of chemostat allowed control of growth rate and exact estimation of the extracellular specific protein production rate (SPPR. We find that major biosynthetic activities are all negatively correlated with SPPR. We also find that expression of many genes of secreted proteins and secondary metabolism, as well as various lineage specific, mostly unknown genes are positively correlated with SPPR. Finally, we enumerate possible regulators and regulatory mechanisms, arising from the data, for this response. Conclusions Based on these results it appears that in low growth rate protein production energy is very efficiently used primarly for protein production. Also, we propose that flux through early glycolysis or the TCA cycle is a more fundamental determining factor than growth rate for low growth rate protein production and we propose a novel eukaryotic response to this i.e. the lineage specific response (LSR.
A system for denial-of-service attack detection based on multivariate correlation analysis
Tan, Zhiyuan; Jamdagni, Aruna; He, Xiangjian; Nanda, Priyadarsi; Liu, Ren Ping
Interconnected systems, such as Web servers, database servers, cloud computing servers and so on, are now under threads from network attackers. As one of most common and aggressive means, denial-of-service (DoS) attacks cause serious impact on these computing systems. In this paper, we present a DoS
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…
Seidel, T; Sankarankutty, A C; Sachse, F B
2017-11-01
The transverse tubular system (t-system) of ventricular cardiomyocytes is essential for efficient excitation-contraction coupling. In cardiac diseases, such as heart failure, remodeling of the t-system contributes to reduced cardiac contractility. However, mechanisms of t-system remodeling are incompletely understood. Prior studies suggested an association with altered cardiac biomechanics and gene expression in disease. Since fibrosis may alter tissue biomechanics, we investigated the local microscopic association of t-system remodeling with fibrosis in a rabbit model of myocardial infarction (MI). Biopsies were taken from the MI border zone of 6 infarcted hearts and from 6 control hearts. Using confocal microscopy and automated image analysis, we quantified t-system integrity (I TT ) and the local fraction of extracellular matrix (f ECM ). In control, f ECM was 18 ± 0.3%. I TT was high and homogeneous (0.07 ± 0.006), and did not correlate with f ECM (R 2 = 0.05 ± 0.02). The MI border zone exhibited increased f ECM within 3 mm from the infarct scar (30 ± 3.5%, p < 0.01 vs control), indicating fibrosis. Myocytes in the MI border zone exhibited significant t-system remodeling, with dilated, sheet-like components, resulting in low I TT (0.03 ± 0.008, p < 0.001 vs control). While both f ECM and t-system remodeling decreased with infarct distance, I TT correlated better with decreasing f ECM (R 2 = 0.44) than with infarct distance (R 2 = 0.24, p < 0.05). Our results show that t-system remodeling in the rabbit MI border zone resembles a phenotype previously described in human heart failure. T-system remodeling correlated with the amount of local fibrosis, which is known to stiffen cardiac tissue, but was not found in regions without fibrosis. Thus, locally altered tissue mechanics may contribute to t-system remodeling. Copyright © 2017 Elsevier Ltd. All rights reserved.
An automated system for the correlation measurement of γ-quanta energy distribution
International Nuclear Information System (INIS)
Ofengenden, R.G.; Berezin, F.N.; Patlan', Yu.V.; Shalejko, A.M.; Shidlyk, A.M.; Shchur, A.M.
1983-01-01
Hardware and software are described in brief for an automated system, to measure the energy and time distributions of gamma-quanta, which ensures accumulation and preliminary processing of experimental data while realizing various physical techniques for investigation. The system is based on the SM-4 computer and electronic-physical equipment produced in the CAMAC standard. In the SM-4 computer the RAFOS operational system is employed which has some advantages in solving the tasks of multidimensional data acquisition and analysis, when a high response and real-time operation are reqUired. Certain components of soltware are worked oUt and included in the system: an operational system version with a larger set of drivers which is adapted to the equipment configuration used; library of macrodeterminations and service object library; subsystem of tuning and testing; subsystem of data acquisition and initial processing
Directory of Open Access Journals (Sweden)
Jinbeum Jang
2015-03-01
Full Text Available This paper presents a novel auto-focusing system based on a CMOS sensor containing pixels with different phases. Robust extraction of features in a severely defocused image is the fundamental problem of a phase-difference auto-focusing system. In order to solve this problem, a multi-resolution feature extraction algorithm is proposed. Given the extracted features, the proposed auto-focusing system can provide the ideal focusing position using phase correlation matching. The proposed auto-focusing (AF algorithm consists of four steps: (i acquisition of left and right images using AF points in the region-of-interest; (ii feature extraction in the left image under low illumination and out-of-focus blur; (iii the generation of two feature images using the phase difference between the left and right images; and (iv estimation of the phase shifting vector using phase correlation matching. Since the proposed system accurately estimates the phase difference in the out-of-focus blurred image under low illumination, it can provide faster, more robust auto focusing than existing systems.
Vilardy, Juan M.; Millán, María. S.; Pérez-Cabré, Elisabet
2017-08-01
We present the results of the noise and occlusion tests in the Gyrator domain (GD) for a joint transform correlator-based encryption system. This encryption system was recently proposed and it was implemented by using a fully phase nonzero-order joint transform correlator (JTC) and the Gyrator transform (GT). The decryption system was based on two successive GTs. In this paper, we make several numerical simulations in order to test the performance and robustness of the JTC-based encryption-decryption system in the GD when the encrypted image is corrupted by noise or occlusion. The encrypted image is affected by additive and multiplicative noise. We also test the effect of data loss due to partial occlusion of the encrypted information. Finally, we evaluate the performance and robustness of the encryption-decryption system in the GD by using the metric of the root mean square error (RMSE) between the original image and the decrypted image when the encrypted image is degraded by noise or modified by occlusion.
Wu, Ya-Ting; Wong, Wai-Ki; Leung, Shu-Hung; Zhu, Yue-Sheng
This paper presents the performance analysis of a De-correlated Modified Code Tracking Loop (D-MCTL) for synchronous direct-sequence code-division multiple-access (DS-CDMA) systems under multiuser environment. Previous studies have shown that the imbalance of multiple access interference (MAI) in the time lead and time lag portions of the signal causes tracking bias or instability problem in the traditional correlating tracking loop like delay lock loop (DLL) or modified code tracking loop (MCTL). In this paper, we exploit the de-correlating technique to combat the MAI at the on-time code position of the MCTL. Unlike applying the same technique to DLL which requires an extensive search algorithm to compensate the noise imbalance which may introduce small tracking bias under low signal-to-noise ratio (SNR), the proposed D-MCTL has much lower computational complexity and exhibits zero tracking bias for the whole range of SNR, regardless of the number of interfering users. Furthermore, performance analysis and simulations based on Gold codes show that the proposed scheme has better mean square tracking error, mean-time-to-lose-lock and near-far resistance than the other tracking schemes, including traditional DLL (T-DLL), traditional MCTL (T-MCTL) and modified de-correlated DLL (MD-DLL).
International Nuclear Information System (INIS)
Jia Zhenglin; Mei Dongcheng
2010-01-01
We investigate the effects of the noise parameters and immunization strength β on the dynamical properties of a tumor growth system with both immunization and colored cross-correlated noises. The analytical expressions for the associated relaxation time T C and the normalized correlation function C(s) are derived by means of the projection operator method. The results indicate that: (i) T C as a function of the multiplicative noise intensity α shows resonance-like behavior, i.e. the curves of T C versus α exhibit a single-peak structure and its peak position changes with increasing correlation strength between noises λ, the autocorrelation time of multiplicative noise τ 1 , the autocorrelation time of additive noise τ 2 and the cross-correlation time τ 3 . This behavior can be understood in terms of the noise-enhanced stability effect and the influence of the memory effects on it. (ii) The increasing λ, τ 1 , τ 2 and the additive noise intensity D slow down the fluctuation decay of the tumor population, whereas the increasing τ 3 and β speed it up. (iii) C(s) increases as λ, τ 1 , τ 2 and β increase, while it decreases with τ 3 increasing. Our study shows that the effects of some noise parameters on tumor growth can be modified due to the presence of the immunization effect.
Jia, Zheng-Lin; Mei, Dong-Cheng
2010-05-01
We investigate the effects of the noise parameters and immunization strength β on the dynamical properties of a tumor growth system with both immunization and colored cross-correlated noises. The analytical expressions for the associated relaxation time TC and the normalized correlation function C(s) are derived by means of the projection operator method. The results indicate that: (i) TC as a function of the multiplicative noise intensity α shows resonance-like behavior, i.e. the curves of TC versus α exhibit a single-peak structure and its peak position changes with increasing correlation strength between noises λ, the autocorrelation time of multiplicative noise τ1, the autocorrelation time of additive noise τ2 and the cross-correlation time τ3. This behavior can be understood in terms of the noise-enhanced stability effect and the influence of the memory effects on it. (ii) The increasing λ, τ1, τ2 and the additive noise intensity D slow down the fluctuation decay of the tumor population, whereas the increasing τ3 and β speed it up. (iii) C(s) increases as λ, τ1, τ2 and β increase, while it decreases with τ3 increasing. Our study shows that the effects of some noise parameters on tumor growth can be modified due to the presence of the immunization effect.
Bischoff, Jan-Moritz; Jeckelmann, Eric
2017-11-01
We improve the density-matrix renormalization group (DMRG) evaluation of the Kubo formula for the zero-temperature linear conductance of one-dimensional correlated systems. The dynamical DMRG is used to compute the linear response of a finite system to an applied ac source-drain voltage; then the low-frequency finite-system response is extrapolated to the thermodynamic limit to obtain the dc conductance of an infinite system. The method is demonstrated on the one-dimensional spinless fermion model at half filling. Our method is able to replicate several predictions of the Luttinger liquid theory such as the renormalization of the conductance in a homogeneous conductor, the universal effects of a single barrier, and the resonant tunneling through a double barrier.
DEFF Research Database (Denmark)
Ibrom, Andreas; Dellwik, Ebba; Flyvbjerg, Henrik K.
2007-01-01
datasets for this substantial measurement error. In contrast to earlier studies, a large number of spectra and raw data have been used in the analysis to define the low-pass filtering characteristic of the EC system. This revealed that the cut-off frequency of the closed-path EC system for water vapour......Turbulent water vapour fluxes measured with closed-path eddy correlation (EC) systems are unintentionally low-pass filtered by the system in a manner that varies with environmental conditions. Why and how is described here. So is the practical method that systematically corrects long-term flux...... concentration measurements decreases exponentially with increasing relative humidity. After correction for this unintended filtering, the fluxes are consistent with CO2 and H2O fluxes that were measured with an open-path sensor at the same time. The correction of water vapour flux measurements over a Beech...
Clinical correlates of faecal incontinence in systemic sclerosis: identifying therapeutic avenues.
Richard, Nicolas; Hudson, Marie; Gyger, Geneviève; Baron, Murray; Sutton, Evelyn; Khalidi, Nader; Pope, Janet E; Carrier, Nathalie; Larché, Maggie; Albert, Alexandra; Fortin, Paul R; Thorne, Carter; Masetto, Ariel
2017-04-01
The aim was to establish the prevalence and severity of faecal incontinence (FI) in SSc, its association with other intestinal manifestations and potential predictors of FI, and its impact on quality of life. A multicentre, cross-sectional study of 298 SSc subjects followed in the Canadian Scleroderma Research Group cohort was performed using validated questionnaires: Jorge-Wexner score (an FI severity scale), Bristol stool scale (a visual scale of stool consistency) and FI Quality-of-Life scale. Constipation was defined by the Rome III criteria. Associations between the Jorge-Wexner score and other clinical variables were determined using multivariate regression analyses. Eighty-one (27.2%) subjects had FI, which was mild in 37 (12.4%) and moderate to severe in 44 (14.8%). Most patients had well-formed stools, 111 (38.8%) reported constipation and 38 (13.4%) had been previously treated for small intestinal bacterial overgrowth (SIBO). Variables independently associated with FI were: loose vs well-formed stools [odds ratio (OR) = 7.01, 95% CI: 2.09, 23.51)], constipation (OR = 3.64, 95% CI: 1.61, 8.27, P = 0.002), history of SIBO (OR = 2.97, 95% CI: 1.06, 8.27) and urinary incontinence (OR = 2.45, 95% CI: 1.14, 5.27). Quality of life measured with the FI Quality-of-Life scale was inversely correlated with FI severity (correlation coefficients between -0.602 and -0.702, P < 0.001). FI was common and often severe in SSc. Loose stools, SIBO, constipation and urinary incontinence were strongly associated with FI. Other than targeting anorectal dysfunction, concomitant treatment of clinical correlates could lead to improvement in FI and quality of life in SSc. © The Author 2016. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: journals.permissions@oup.com
DEFF Research Database (Denmark)
Pratas, Nuno; Marchetti, Nicola; Prasad, Neeli R.
2010-01-01
on cooperative sensing schemes. The analysis is supported by evaluation metrics which accounts for the perceived capacity limits. The analysis is performed along the data fusion chain, comparing several scenarios encompassing different degrees of environment correlation between the cluster nodes, number......Spectrum sensing, the cornerstone of the Cognitive Radio paradigm, has been the focus of intensive research, from which the main conclusion was that its performance can be greatly enhanced through the use of cooperative sensing schemes. Nevertheless, if a proper design of the cooperative scheme...... is not followed, then the use of cooperative schemes will introduce some limitations in the network perceived capacity. In this paper, we analyze the performance of a cooperative spectrum sensing scheme based on Data Fusion, by measuring the perceived capacity limits introduced by the use of Data Fusion...
DEFF Research Database (Denmark)
Thomalla, Götz; Siebner, Hartwig R; Jonas, Melanie
2009-01-01
Gilles de la Tourette syndrome (GTS) is a neuropsychiatric disorder characterized by multiple motor and vocal tics. Previous structural MRI studies have identified regional abnormalities in grey matter, especially in the basal ganglia. These findings are consistent with the assumption...... of white matter changes in GTS. In this study, we aimed to examine whether GTS is associated with abnormalities in white matter microstructure and whether these changes are correlated with tic severity. In a morphometric study based on diffusion tensor MRI of the whole brain, we compared brain tissue...... the groups. We also tested for a linear relationship between regional FA values and clinical scores of tic severity. Probabilistic fibre tracking was applied to characterize anatomical connectivity of those areas showing differences in regional FA. Compared with healthy controls, GTS patients showed...
Igoshev, P. A.; Timirgazin, M. A.; Arzhnikov, A. K.; Antipin, T. V.; Irkhin, V. Yu.
2017-10-01
The ground-state magnetic phase diagram is calculated within the Hubbard and s-d exchange (Kondo) models for square and simple cubic lattices vs. band filling and interaction parameter. The difference of the results owing to the presence of localized moments in the latter model is discussed. We employ a generalized Hartree-Fock approximation (HFA) to treat commensurate ferromagnetic (FM), antiferromagnetic (AFM), and incommensurate (spiral) magnetic phases. The electron correlations are taken into account within the Hubbard model by using the Kotliar-Ruckenstein slave boson approximation (SBA). The main advantage of this approach is a correct qualitative description of the paramagnetic phase: its energy becomes considerably lower as compared with HFA, and the gain in the energy of magnetic phases is substantially reduced.
[Correlations of central nervous system and thyroid function under chronic emotional stress].
Amiragova, M G; Arkhangel'skaia, M I
1982-06-01
Experiments on cats exposed to chronic emotional stress induced during one week by 4-hour immobilization of the animals in conjunction with aperiodic electrocutaneous stimulation were made to study correlations of the time course of changes in the EEG of the cortical and subcortical structures and the content of thyroxin in the peripheral blood at varying time of the experiments. It was demonstrated that in the course of stress, the EEG manifests the cycles of "burst" activity of slow waves, which are first recorded in the posterior hypothalamus and then get generalized. This is accompanied by a significantly high thyroxin secretion. As the stress exposures are repeated, the EEG changes become dominant, also corresponding with high thyroxin secretion. After the experiments are over, the cycles of "burst" activity accompanied by enhanced thyroid function are still recordable over several days.
Auxiliary-Field Quantum Monte Carlo Simulations of Strongly-Correlated Systems, the Final Report
Energy Technology Data Exchange (ETDEWEB)
Chang, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
2017-11-07
In this final report, we present preliminary results of ground state phases of interacting spinless Dirac fermions. The name "Dirac fermion" originates from the fact that low-energy excitations of electrons hopping on the honeycomb lattice are described by a relativistic Dirac equation. Dirac fermions have received much attention particularly after the seminal work of Haldale1 which shows that the quantum Hall physics can be realized on the honeycomb lattice without magnetic fields. Haldane's work later becomes the foundation of topological insulators (TIs). While the physics of TIs is based largely on spin-orbit coupled non-interacting electrons, it was conjectured that topological insulators can be induced by strong correlations alone.
Wavepacket dynamics in one-dimensional system with long-range correlated disorder
Yamada, Hiroaki S.
2018-03-01
We numerically investigate dynamical property in the one-dimensional tight-binding model with long-range correlated disorder having power spectrum 1 /fα (α: spectrum exponent) generated by Fourier filtering method. For relatively small α MSD) of the initially localized wavepacket shows ballistic spread and localizes as time elapses. It is shown that α-dependence of the dynamical localization length determined by the MSD exhibits a simple scaling law in the localization regime for the relatively weak disorder strength W. Furthermore, scaled MSD by the dynamical localization length almost obeys an universal function from the ballistic to the localization regime in the various combinations of the parameters α and W.
Meadors, Grant David; Krishnan, Badri; Papa, Maria Alessandra; Whelan, John T.; Zhang, Yuanhao
2018-02-01
Continuous-wave (CW) gravitational waves (GWs) call for computationally-intensive methods. Low signal-to-noise ratio signals need templated searches with long coherent integration times and thus fine parameter-space resolution. Longer integration increases sensitivity. Low-mass x-ray binaries (LMXBs) such as Scorpius X-1 (Sco X-1) may emit accretion-driven CWs at strains reachable by current ground-based observatories. Binary orbital parameters induce phase modulation. This paper describes how resampling corrects binary and detector motion, yielding source-frame time series used for cross-correlation. Compared to the previous, detector-frame, templated cross-correlation method, used for Sco X-1 on data from the first Advanced LIGO observing run (O1), resampling is about 20 × faster in the costliest, most-sensitive frequency bands. Speed-up factors depend on integration time and search setup. The speed could be reinvested into longer integration with a forecast sensitivity gain, 20 to 125 Hz median, of approximately 51%, or from 20 to 250 Hz, 11%, given the same per-band cost and setup. This paper's timing model enables future setup optimization. Resampling scales well with longer integration, and at 10 × unoptimized cost could reach respectively 2.83 × and 2.75 × median sensitivities, limited by spin-wandering. Then an O1 search could yield a marginalized-polarization upper limit reaching torque-balance at 100 Hz. Frequencies from 40 to 140 Hz might be probed in equal observing time with 2 × improved detectors.
Kavaliunas, Andrius; Wiberg, Michael; Tinghög, Petter; Glaser, Anna; Gyllensten, Hanna; Alexanderson, Kristina; Hillert, Jan
2015-01-01
Multiple sclerosis (MS) patients earn lower incomes and receive higher benefits. However, there is limited knowledge of how this is correlated with their disability. To elucidate sources and levels of income among MS patients with different disability, assessed with the Expanded Disability Status Scale. A total of 7929 MS patients aged 21-64 years and living in Sweden in 2010 were identified for this cross-sectional study. Descriptive statistics, logistic and truncated linear regression models were used to estimate differences between MS patients regarding earnings, disability pension, sickness absence, disability allowance, unemployment compensation, and social assistance. The average level of earnings was ten times lower and the average level of health- related benefits was four times higher when comparing MS patients with severe and mild disability. MS patients with severe disability had on average SEK 166,931 less annual income from earnings and SEK 54,534 more income from benefits compared to those with mild disability. The combined average income for MS patients was 35% lower when comparing patients in the same groups. The adjusted risk ratio for having earnings among MS patients with severe disability compared to the patients with mild disability was 0.33 (95% CI 0.29-0.39), while the risk ratio for having benefits was 1.93 (95% CI 1.90-1.94). Disease progression affects the financial situation of MS patients considerably. Correlations between higher disability and patient income were observed, suggesting that earnings and benefits could be used as measures of MS progression and proxies of disability.
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.
International Nuclear Information System (INIS)
Brorsen, Kurt R.; Sirjoosingh, Andrew; Pak, Michael V.; Hammes-Schiffer, Sharon
2015-01-01
The nuclear electronic orbital (NEO) reduced explicitly correlated Hartree-Fock (RXCHF) approach couples select electronic orbitals to the nuclear orbital via Gaussian-type geminal functions. This approach is extended to enable the use of a restricted basis set for the explicitly correlated electronic orbitals and an open-shell treatment for the other electronic orbitals. The working equations are derived and the implementation is discussed for both extensions. The RXCHF method with a restricted basis set is applied to HCN and FHF − and is shown to agree quantitatively with results from RXCHF calculations with a full basis set. The number of many-particle integrals that must be calculated for these two molecules is reduced by over an order of magnitude with essentially no loss in accuracy, and the reduction factor will increase substantially for larger systems. Typically, the computational cost of RXCHF calculations with restricted basis sets will scale in terms of the number of basis functions centered on the quantum nucleus and the covalently bonded neighbor(s). In addition, the RXCHF method with an odd number of electrons that are not explicitly correlated to the nuclear orbital is implemented using a restricted open-shell formalism for these electrons. This method is applied to HCN + , and the nuclear densities are in qualitative agreement with grid-based calculations. Future work will focus on the significance of nonadiabatic effects in molecular systems and the further enhancement of the NEO-RXCHF approach to accurately describe such effects
Energy Technology Data Exchange (ETDEWEB)
Brorsen, Kurt R.; Sirjoosingh, Andrew; Pak, Michael V.; Hammes-Schiffer, Sharon, E-mail: shs3@illinois.edu [Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Ave., Urbana, Illinois 61801 (United States)
2015-06-07
The nuclear electronic orbital (NEO) reduced explicitly correlated Hartree-Fock (RXCHF) approach couples select electronic orbitals to the nuclear orbital via Gaussian-type geminal functions. This approach is extended to enable the use of a restricted basis set for the explicitly correlated electronic orbitals and an open-shell treatment for the other electronic orbitals. The working equations are derived and the implementation is discussed for both extensions. The RXCHF method with a restricted basis set is applied to HCN and FHF{sup −} and is shown to agree quantitatively with results from RXCHF calculations with a full basis set. The number of many-particle integrals that must be calculated for these two molecules is reduced by over an order of magnitude with essentially no loss in accuracy, and the reduction factor will increase substantially for larger systems. Typically, the computational cost of RXCHF calculations with restricted basis sets will scale in terms of the number of basis functions centered on the quantum nucleus and the covalently bonded neighbor(s). In addition, the RXCHF method with an odd number of electrons that are not explicitly correlated to the nuclear orbital is implemented using a restricted open-shell formalism for these electrons. This method is applied to HCN{sup +}, and the nuclear densities are in qualitative agreement with grid-based calculations. Future work will focus on the significance of nonadiabatic effects in molecular systems and the further enhancement of the NEO-RXCHF approach to accurately describe such effects.
Geometric correlations and multifractals
International Nuclear Information System (INIS)
Amritkar, R.E.
1991-07-01
There are many situations where the usual statistical methods are not adequate to characterize correlations in the system. To characterize such situations we introduce mutual correlation dimensions which describe geometric correlations in the system. These dimensions allow us to distinguish between variables which are perfectly correlated with or without a phase lag, variables which are uncorrelated and variables which are partially correlated. We demonstrate the utility of our formalism by considering two examples from dynamical systems. The first example is about the loss of memory in chaotic signals and describes auto-correlations while the second example is about synchronization of chaotic signals and describes cross-correlations. (author). 19 refs, 6 figs
Quantum correlations in a system of nuclear s = 1/2 spins in a strong magnetic field
International Nuclear Information System (INIS)
Fel’dman, E B; Kuznetsova, E I; Yurishchev, M A
2012-01-01
Entanglement and quantum discord for a pair of nuclear spins s = 1/2 in a nanopore filled with a gas of spin-carrying molecules (atoms) are studied. The correlation functions describing dynamics of dipolar-coupled spins in a nanopore are found. The dependence of spin-pair entanglement on the temperature and the number of spins is obtained from the reduced density matrix, which is centrosymmetric (CS). An analytic expression for the concurrence is obtained for an arbitrary CS density matrix. It is shown that the quantum discord as a measure of quantum correlations attains a significant value at low temperatures. It is also shown that the discord in the considered model has ‘flickering’ character and disappears periodically in the course of time evolution of the system. The geometric discord is studied for arbitrary 4 × 4 CS density matrices. (paper)
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.
Energy Technology Data Exchange (ETDEWEB)
Davis, P; Russell, A S; Percy, J S
1976-12-01
Antibodies to ultraviolet light denatured DNA (UV DNA) have been measured in patients with systemic lupus erythematosus (SLE) and normal subjects, using a millipore filter radioimmunoassay. High levels of UV DNA binding were only found in patients with SLE. The presence of UV DNA antibodies correlated well with the presence of native DNA antibodies, although immunodiffusion studies and inhibition techniques showed these antibodies to be immunologically distinct in many cases. Forty-one percent of the SLE patients had had photosensitivity at some stage of their disease, but there was a poor correlation between this symptom and the presence of UV DNA antibodies. Although UV DNA is known to be a potent immunogen, none of the results from this study suggests that antibodies to UV DNA are more than another example of the broad spectrum of antinuclear antibodies seen in SLE.
Quantum glassiness in clean strongly correlated systems: an example of topological overprotection
Chamon, Claudio
2005-03-01
Describing matter at near absolute zero temperature requires understanding a system's quantum ground state and the low energy excitations around it, the quasiparticles, which are thermally populated by the system's contact to a heat bath. However, this paradigm breaks down if thermal equilibration is obstructed. I present solvable examples of quantum many-body Hamiltonians of systems that are unable to reach their ground states as the environment temperature is lowered to absolute zero. These examples, three dimensional generalizations of quantum Hamiltonians proposed for topological quantum computing, 1) have no quenched disorder, 2) have solely local interactions, 3) have an exactly solvable spectrum, 4) have topologically ordered ground states, and 5) have slow dynamical relaxation rates akin to those of strong structural glasses.
DEFF Research Database (Denmark)
Vogel, A; Bhattacharya, S; Larsen, J L
2011-01-01
This study examined the prevalence of cognitive impairment and its association with depressive symptoms and self-reported cognitive complaints in Danish outpatients with systemic lupus erythematosus (SLE). Fifty-seven consecutive female SLE-outpatients were examined with a comprehensive neuropsyc......This study examined the prevalence of cognitive impairment and its association with depressive symptoms and self-reported cognitive complaints in Danish outpatients with systemic lupus erythematosus (SLE). Fifty-seven consecutive female SLE-outpatients were examined with a comprehensive...
Sandqvist, Gunnel; Scheja, Agneta; Hesselstrand, Roger
2010-09-01
To identify factors, individual and work related, influencing work ability, and to assess the association between work ability and employment status, activities of daily life (ADLs) and quality of life in patients with SSc. Fifty-seven consecutive patients (53 females/4 males) with SSc (47 lcSSc/10 dcSSc) were included. Median age was 58 [interquartile range (IQR) 47-62] years and disease duration 14 (9-19) years. The patients were assessed for socio-demographic characteristics, disease parameters, symptoms, work ability, empowerment and adaptations in a workplace, social support, ADLs and quality of life. Work ability, assessed with the Work Ability Index (WAI) could be evaluated in 48 of 57 patients. The correlation between employment status and WAI was good (r(s) = 0.79, P work (P work (P Employment interventions should include support in job adaptations as well as self-management strategies to help patients deal with pain and fatigue and to enhance the confidence to perform their work.
A Computer Aided System for Correlation and Prediction of Phase Equilibrium Data
DEFF Research Database (Denmark)
Nielsen, T.L.; Gani, Rafiqul
2001-01-01
based on mathematical programming. This paper describes the development of a computer aided system for the systematic derivation of appropriate property models to be used in the service role for a specified problem. As a first step, a library of well-known property models ha's been developed...
Watanabe, Eriko; Ishikawa, Mami; Ohta, Maiko; Kodate, Kashiko
2005-09-01
Face recognition is used in a wide range of security systems, such as monitoring credit card use, searching for individuals with street cameras via Internet and maintaining immigration control. There are still many technical subjects under study. For instance, the number of images that can be stored is limited under the current system, and the rate of recognition must be improved to account for photo shots taken at different angles under various conditions. We implemented a fully automatic Fast Face Recognition Optical Correlator (FARCO) system by using a 1000 frame/s optical parallel correlator designed and assembled by us. Operational speed for the 1: N (i.e. matching a pair of images among N, where N refers to the number of images in the database) identification experiment (4000 face images) amounts to less than 1.5 seconds, including the pre/post processing. From trial 1: N identification experiments using FARCO, we acquired low error rates of 2.6% False Reject Rate and 1.3% False Accept Rate. By making the most of the high-speed data-processing capability of this system, much more robustness can be achieved for various recognition conditions when large-category data are registered for a single person. We propose a face recognition algorithm for the FARCO while employing a temporal image sequence of moving images. Applying this algorithm to a natural posture, a two times higher recognition rate scored compared with our conventional system. The system has high potential for future use in a variety of purposes such as search for criminal suspects by use of street and airport video cameras, registration of babies at hospitals or handling of an immeasurable number of images in a database.
International Nuclear Information System (INIS)
Kilic, Tuerker; Ozduman, Koray; Cavdar, Safiye; Oezek, M. Memet; Pamir, M. Necmettin
2005-01-01
Objective: This study aims at evaluating the adequacy of digital subtraction angiography and magnetic resonance venography in imaging of the galenic venous system for surgical planning of approaches to the pineal region. Anatomical dissections were carried out in 10 cadavers of several age groups and these were compared to imaging findings in 10 living subjects. Methods: The presence or absence of 10 predetermined veins or vein groupings belonging to the galenic venous system were prospectively analyzed in 10 cadaver dissections and imaging findings of 10 age matched human subjects. The studied vessels were the vein of galen, the internal cerebral veins, both basal vein of Rosenthals, internal occipital vein, occipitotemporal veins, precentral cerebellar veins, tectal veins, pineal veins, superior vermian veins (including superior cerebellar veins (SCVs)) and posterior pericallosal veins. Each of the subjects had both digital subtraction angiography and magnetic resonance venography studies performed. Diagnostic digital subtraction angiography was performed using the transfemoral route and the venous phase was used for the study. Magnetic resonance venography was performed in 1.5 T MRI equipment using the 2D-TOF sequence. All studies were reported to be normal. Results: There was wide variation in the anatomy of the galenic venous system. There were interpersonal, intrapersonal and age related variations. Both the digital subtraction angiography and the magnetic resonance venography were efficient at demonstrating large veins. However, smaller veins were less readily demonstrated in either study. The general sensitivities of the digital subtraction angiography and the magnetic resonance venography for the galenic venous system were 45.5% and 32.5%, respectively. Surgically important veins were missed in most studies. Conclusions: Anatomically, the galenic venous system is highly variable. This variability is caused by interpersonal, intrapersonal and age related
Energy Technology Data Exchange (ETDEWEB)
Kilic, Tuerker [Marmara University, Department of Neurosurgery, PK 53, Maltepe, 81532 Istanbul (Turkey) and Marmara University, Department of Anatomy, Istanbul (Turkey)]. E-mail: turkilic@tnn.net; Ozduman, Koray [Marmara University, Department of Neurosurgery, PK 53, Maltepe, 81532 Istanbul (Turkey); Cavdar, Safiye [Marmara University, Department of Anatomy, Istanbul (Turkey); Oezek, M. Memet [Marmara University, Department of Neurosurgery, PK 53, Maltepe, 81532 Istanbul (Turkey); Pamir, M. Necmettin [Marmara University, Department of Neurosurgery, PK 53, Maltepe, 81532 Istanbul (Turkey)
2005-11-01
Objective: This study aims at evaluating the adequacy of digital subtraction angiography and magnetic resonance venography in imaging of the galenic venous system for surgical planning of approaches to the pineal region. Anatomical dissections were carried out in 10 cadavers of several age groups and these were compared to imaging findings in 10 living subjects. Methods: The presence or absence of 10 predetermined veins or vein groupings belonging to the galenic venous system were prospectively analyzed in 10 cadaver dissections and imaging findings of 10 age matched human subjects. The studied vessels were the vein of galen, the internal cerebral veins, both basal vein of Rosenthals, internal occipital vein, occipitotemporal veins, precentral cerebellar veins, tectal veins, pineal veins, superior vermian veins (including superior cerebellar veins (SCVs)) and posterior pericallosal veins. Each of the subjects had both digital subtraction angiography and magnetic resonance venography studies performed. Diagnostic digital subtraction angiography was performed using the transfemoral route and the venous phase was used for the study. Magnetic resonance venography was performed in 1.5 T MRI equipment using the 2D-TOF sequence. All studies were reported to be normal. Results: There was wide variation in the anatomy of the galenic venous system. There were interpersonal, intrapersonal and age related variations. Both the digital subtraction angiography and the magnetic resonance venography were efficient at demonstrating large veins. However, smaller veins were less readily demonstrated in either study. The general sensitivities of the digital subtraction angiography and the magnetic resonance venography for the galenic venous system were 45.5% and 32.5%, respectively. Surgically important veins were missed in most studies. Conclusions: Anatomically, the galenic venous system is highly variable. This variability is caused by interpersonal, intrapersonal and age related
Lambertz, Markus; Bertozzo, Filippo; Sander, P Martin
2018-01-01
Air sacs are an important component of the avian respiratory system, and corresponding structures also were crucial for the evolution of sauropod dinosaur gigantism. Inferring the presence of air sacs in fossils so far is restricted to bones preserving internal pneumatic cavities and foramina as osteological correlates. We here present bone histological correlates for air sacs as a new potential identification tool for these elements of the respiratory system. The analysis of several avian and non-avian dinosaur samples revealed delicate fibres in secondary trabecular and secondary endosteal bone that in the former case (birds) is known or in the latter (non-avian dinosaurs) assumed to have been in contact with air sacs, respectively. The bone histology of this 'pneumosteal tissue' is markedly different from those regions where muscles attached presenting classical Sharpey's fibres. The pneumatized bones of several non-dinosaurian taxa do not exhibit the characteristics of this 'pneumosteum'. Our new histology-based approach thus can be instrumental in reconstructing the origin of air sacs among dinosaurs and hence for our understanding of this remarkable evolutionary novelty of the respiratory system. © 2018 The Author(s).
Theory of heavy-fermion compounds theory of strongly correlated Fermi-systems
Amusia, Miron Ya; Shaginyan, Vasily R; Stephanovich, Vladimir A
2015-01-01
This book explains modern and interesting physics in heavy-fermion (HF) compounds to graduate students and researchers in condensed matter physics. It presents a theory of heavy-fermion (HF) compounds such as HF metals, quantum spin liquids, quasicrystals and two-dimensional Fermi systems. The basic low-temperature properties and the scaling behavior of the compounds are described within the framework of the theory of fermion condensation quantum phase transition (FCQPT). Upon reading the book, the reader finds that HF compounds with quite different microscopic nature exhibit the same non-Fermi liquid behavior, while the data collected on very different HF systems have a universal scaling behavior, and these compounds are unexpectedly uniform despite their diversity. For the reader's convenience, the analysis of compounds is carried out in the context of salient experimental results. The numerous calculations of the non-Fermi liquid behavior, thermodynamic, relaxation and transport properties, being in good...
Froes Asmus, Carmen I R; Camara, Volney M; Raggio, Ronir; Landrigan, Philip J; Claudio, Luz
2017-10-01
This study investigated the association between pesticide exposure in Brazil (2005-2013) with rates of central nervous system (CNS) and cardiovascular system (CVS) congenital abnormalities in 2014. An exposure variable was established from data on production and sales of pesticides (kg) per crop area (ha) for 2012 and 2013 years. The Brazilian states were divided into three categories: high, medium, and low pesticide use and rate ratios were estimated for each group of states (CI: 95 %). In 2013 and 2014, the high use group presented a 100 and a 75 % increase, and the medium group a 65 and 23 % increase, respectively, in the risk of CNS and CVS congenital abnormalities at birth, compared to the low use group. These findings suggest that pesticide exposure could be associated with increased risk of congenital malformations at birth in Brazil.
Semiclassical approach to mesoscopic systems classical trajectory correlations and wave interference
Waltner, Daniel
2012-01-01
This volume describes mesoscopic systems with classically chaotic dynamics using semiclassical methods which combine elements of classical dynamics and quantum interference effects. Experiments and numerical studies show that Random Matrix Theory (RMT) explains physical properties of these systems well. This was conjectured more than 25 years ago by Bohigas, Giannoni and Schmit for the spectral properties. Since then, it has been a challenge to understand this connection analytically. The author offers his readers a clearly-written and up-to-date treatment of the topics covered. He extends previous semiclassical approaches that treated spectral and conductance properties. He shows that RMT results can in general only be obtained semiclassically when taking into account classical configurations not considered previously, for example those containing multiply traversed periodic orbits. Furthermore, semiclassics is capable of describing effects beyond RMT. In this context he studies the effect of a non-zero Eh...
Murumkar, A. R.; Gupta, S.; Kaurwar, A.; Satankar, R. K.; Mounish, N. K.; Pitta, D. S.; Virat, J.; Kumar, G.; Hatte, S.; Tripathi, R. S.; Shedekar, V.; George, K. J.; Plappally, A. K.
2015-12-01
In India, the present value of water, both potable and not potable, bears no relation to the energy of water production. However, electrical energy spent on ground water extraction alone is equivalent to the nation's hydroelectric capacity of 40.1 GWh. Likewise, desalinating 1m3 water of the Bay of Bengal would save three times the energy for potable ground water extraction along the coast of the Bay. It is estimated that every second woman in rural India expends 0.98 kWhe/m3/d for bringing water for household needs. Yet, the water-energy nexus remains to be a topic which is gravely ignored. This is largely caused by factors such as lack of awareness, defective public policies, and intrusive cultural practices. Furthermore, there are instances of unceasing dereliction towards water management and maintenance of the sparsely distributed water and waste water treatment plants across the country. This pollutes the local water across India apart from other geogenic impurities. Additionally, product aesthetics and deceptive advertisements take advantage of the abulia generated by users' ignorance of technical specifications of water technologies and processes in mismanagement of water use. Accordingly, urban residents are tempted to expend on energy intensive water technologies at end use. This worsens the water-energy equation at urban households. Cooking procedures play a significant role in determining the energy expended on water at households. The paper also evaluates total energy expense involved in cultivating some major Kharif and Rabi crops. Manual and traditional agricultural practices are more prominent than mechanized and novel agricultural techniques. The specific energy consumption estimate for different water technologies will help optimize energy expended on water in its life cycles. The implication of the present study of water-energy correlation will help plan and extend water management infrastructure at different locations across India.
Muscular and Systemic Correlates of Resistance Training-Induced Muscle Hypertrophy
Mitchell, Cameron J.; Churchward-Venne, Tyler A.; Bellamy, Leeann; Parise, Gianni; Baker, Steven K.; Phillips, Stuart M.
2013-01-01
PURPOSE: To determine relationships between post-exercise changes in systemic [testosterone, growth hormone (GH), insulin like grow factor 1 (IGF-1) and interleukin 6 (IL-6)], or intramuscular [skeletal muscle androgen receptor (AR) protein content and p70S6K phosphorylation status] factors in a moderately-sized cohort of young men exhibiting divergent resistance training-mediated muscle hypertrophy. METHODS: Twenty three adult males completed 4 sessions•wk⁻¹ of resistance training for 16 wk....
ArunKumar, GaneshPrasad; Soria-Hernanz, David F.; Pitchappan, Ramasamy
2012-01-01
Previous studies that pooled Indian populations from a wide variety of geographical locations, have obtained contradictory conclusions about the processes of the establishment of the Varna caste system and its genetic impact on the origins and demographic histories of Indian populations. To further investigate these questions we took advantage that both Y chromosome and caste designation are paternally inherited, and genotyped 1,680 Y chromosomes representing 12 tribal and 19 non-tribal (cast...
Fanconi anemia: correlating central nervous system malformations and genetic complementation groups.
Johnson-Tesch, Benjamin A; Gawande, Rakhee S; Zhang, Lei; MacMillan, Margaret L; Nascene, David R
2017-06-01
Congenital central nervous system abnormalities in children with Fanconi anemia are poorly characterized, especially with regard to specific genetic complementation groups. To characterize the impact of genetic complementation groups on central nervous system anatomy. Through chart review we identified 36 patients with Fanconi anemia with available brain MRIs at the University of Minnesota (average age, 11.3 years; range, 1-43 years; M:F=19:17), which we reviewed and compared to 19 age- and sex-matched controls (average age, 7.9 years; range, 2-18 years; M:F=9:10). Genotypic information was available for 27 patients (15 FA-A, 2 FA-C, 3 FA-G, and 7 FA-D1 [biallelic mutations in BRCA2 gene]). Of the 36 patients, 61% had at least one congenital central nervous system or skull base abnormality. These included hypoplastic clivus (n=12), hypoplastic adenohypophysis (n=11), platybasia (n=8), pontocerebellar hypoplasia (n=7), isolated pontine hypoplasia (n=4), isolated vermis hypoplasia (n=3), and ectopic neurohypophysis (n=6). Average pituitary volume was significantly less in patients with Fanconi anemia (PFanconi anemia patients (P=0.006), but the basal angle of those with FA-D1 was not significantly different from controls (P=0.239). Clivus length was less in the Fanconi anemia group (P=0.002), but significance was only observed in the FA-D1 subgroup (PFanconi anemia have higher incidences of ectopic neurohypophysis, adenohypophysis hypoplasia, platybasia and other midline central nervous system skull base posterior fossa abnormalities than age- and sex-matched controls. Patients with posterior fossa abnormalities, including pontocerebellar hypoplasia, are more likely to have biallelic BRCA2 mutations.
Fanconi anemia: correlating central nervous system malformations and genetic complementation groups
International Nuclear Information System (INIS)
Johnson-Tesch, Benjamin A.; Gawande, Rakhee S.; Nascene, David R.; Zhang, Lei; MacMillan, Margaret L.
2017-01-01
Congenital central nervous system abnormalities in children with Fanconi anemia are poorly characterized, especially with regard to specific genetic complementation groups. To characterize the impact of genetic complementation groups on central nervous system anatomy. Through chart review we identified 36 patients with Fanconi anemia with available brain MRIs at the University of Minnesota (average age, 11.3 years; range, 1-43 years; M:F=19:17), which we reviewed and compared to 19 age- and sex-matched controls (average age, 7.9 years; range, 2-18 years; M:F=9:10). Genotypic information was available for 27 patients (15 FA-A, 2 FA-C, 3 FA-G, and 7 FA-D1 [biallelic mutations in BRCA2 gene]). Of the 36 patients, 61% had at least one congenital central nervous system or skull base abnormality. These included hypoplastic clivus (n=12), hypoplastic adenohypophysis (n=11), platybasia (n=8), pontocerebellar hypoplasia (n=7), isolated pontine hypoplasia (n=4), isolated vermis hypoplasia (n=3), and ectopic neurohypophysis (n=6). Average pituitary volume was significantly less in patients with Fanconi anemia (P<0.0001) than in controls. Basal angle was significantly greater in Fanconi anemia patients (P=0.006), but the basal angle of those with FA-D1 was not significantly different from controls (P=0.239). Clivus length was less in the Fanconi anemia group (P=0.002), but significance was only observed in the FA-D1 subgroup (P<0.0001). Of the seven patients meeting criteria for pontocerebellar hypoplasia, six belonged to the FA-D1 group. Patients with Fanconi anemia have higher incidences of ectopic neurohypophysis, adenohypophysis hypoplasia, platybasia and other midline central nervous system skull base posterior fossa abnormalities than age- and sex-matched controls. Patients with posterior fossa abnormalities, including pontocerebellar hypoplasia, are more likely to have biallelic BRCA2 mutations. (orig.)
Six-quark configurations in the NN system correlated with experiment
International Nuclear Information System (INIS)
Gorovoy, V.S.; Obukhovskij, I.T.
1996-01-01
The nucleon-nucleon interaction at short range is analyzed in terms of six-quark configuration. It is shown that in low partial waves L = 0, 1 system has a two-channel character: the N N channel and the inner six-quark state (bag) with specific color-spin structure. It is shown that polarization observables could be a good tool for investigation of a quark structure of the deuteron [ru
Quantum Glassiness in Strongly Correlated Clean Systems: An Example of Topological Overprotection
Chamon, Claudio
2005-01-01
This Letter presents solvable examples of quantum many-body Hamiltonians of systems that are unable to reach their ground states as the environment temperature is lowered to absolute zero. These examples, three-dimensional generalizations of quantum Hamiltonians proposed for topological quantum computing, (1)have no quenched disorder, (2)have solely local interactions, (3)have an exactly solvable spectrum, (4)have topologically ordered ground states, and (5)have slow dynamical relaxation rates akin to those of strong structural glasses.
Test of rotating wheel system for measuring correlated α-decay
International Nuclear Information System (INIS)
Wu Xiaolei; Gan Zaiguo; Guo Junsheng; Fan Hongmei; Qin Zhi
2005-01-01
A rotating-wheel set-up used for measuring and studying the heavy nuclei with α-decay was built. This system was tested experimentally by using ion-beam from SFC. The test results prove that this set-up was useful and reliable. It provides simple and effective equipment and technique to synthesize and identify new nuclides of Z=107 in the near future. (authors)
Industrial Unionism and Its Bargaining Correlates in Nigeria Industrial Relations System
Francis C. Anyim; Joy Onyinyechi Ekwoaba; Adedoyinsola Olajumoke Shonuga
2013-01-01
Between 1960-1966, industrial relations system in Nigeria was based on Laissez-faire doctrine or voluntary ethic. The colonial trade union ordinance of 1938 allowed any five or more persons to form trade unions. The trend led to the proliferation of over 1000 mushroom unions which were not well organized and badly managed. Besides, all was not well with the organization, administration, finance, leadership and foreign relations of the unions. It was against this backdrop that government initi...
Fanconi anemia: correlating central nervous system malformations and genetic complementation groups
Energy Technology Data Exchange (ETDEWEB)
Johnson-Tesch, Benjamin A. [University of Minnesota, Department of Radiology, Minneapolis, MN (United States); Gawande, Rakhee S.; Nascene, David R. [University of Minnesota, Department of Radiology, Neuroradiology Section, Minneapolis, MN (United States); Zhang, Lei [University of Minnesota, Biostatistical Design and Analysis Centre, Minneapolis, MN (United States); MacMillan, Margaret L. [University of Minnesota, Blood and Marrow Transplant Program, Department of Pediatrics, Minneapolis, MN (United States)
2017-06-15
Congenital central nervous system abnormalities in children with Fanconi anemia are poorly characterized, especially with regard to specific genetic complementation groups. To characterize the impact of genetic complementation groups on central nervous system anatomy. Through chart review we identified 36 patients with Fanconi anemia with available brain MRIs at the University of Minnesota (average age, 11.3 years; range, 1-43 years; M:F=19:17), which we reviewed and compared to 19 age- and sex-matched controls (average age, 7.9 years; range, 2-18 years; M:F=9:10). Genotypic information was available for 27 patients (15 FA-A, 2 FA-C, 3 FA-G, and 7 FA-D1 [biallelic mutations in BRCA2 gene]). Of the 36 patients, 61% had at least one congenital central nervous system or skull base abnormality. These included hypoplastic clivus (n=12), hypoplastic adenohypophysis (n=11), platybasia (n=8), pontocerebellar hypoplasia (n=7), isolated pontine hypoplasia (n=4), isolated vermis hypoplasia (n=3), and ectopic neurohypophysis (n=6). Average pituitary volume was significantly less in patients with Fanconi anemia (P<0.0001) than in controls. Basal angle was significantly greater in Fanconi anemia patients (P=0.006), but the basal angle of those with FA-D1 was not significantly different from controls (P=0.239). Clivus length was less in the Fanconi anemia group (P=0.002), but significance was only observed in the FA-D1 subgroup (P<0.0001). Of the seven patients meeting criteria for pontocerebellar hypoplasia, six belonged to the FA-D1 group. Patients with Fanconi anemia have higher incidences of ectopic neurohypophysis, adenohypophysis hypoplasia, platybasia and other midline central nervous system skull base posterior fossa abnormalities than age- and sex-matched controls. Patients with posterior fossa abnormalities, including pontocerebellar hypoplasia, are more likely to have biallelic BRCA2 mutations. (orig.)
Blakney, Anna K; Little, Adam B; Jiang, Yonghou; Woodrow, Kim A
2016-11-01
Composite delivery systems where drugs are electrospun in different layers and vary the drug stacking-order are posited to affect bioavailability. We evaluated how the formulation characteristics of both burst- and sustained-release electrospun fibers containing three physicochemically diverse drugs: dapivirine (DPV), maraviroc (MVC) and tenofovir (TFV) affect in vitro and ex vivo release. We developed a poly(hydroxyethyl methacrylate) (pHEMA) hydrogel release platform for the rapid, inexpensive in vitro evaluation of burst- and sustained-release topical or dermal drug delivery systems with varying microarchitecture. We investigated properties of the hydrogel that could recapitulate ex vivo release into nonhuman primate vaginal tissue. Using a dimethyl sulfoxide extraction protocol and high-performance liquid chromatography analysis, we achieved >93% recovery from the hydrogels and >88% recovery from tissue explants for all three drugs. We found that DPV loading, but not stacking order (layers of fiber containing a single drug) or microarchitecture (layers with isolated drug compared to all drugs in the same layer) impacted the burst release in vitro and ex vivo. Our burst-release formulations showed a correlation for DPV accumulation between the hydrogel and tissue (R 2 = 0.80), but the correlation was not significant for MVC or TFV. For the sustained-release formulations, the PLGA/PCL content did not affect TFV release in vitro or ex vivo. Incorporation of cells into the hydrogel matrix improved the correlation between hydrogel and tissue explant release for TFV. We expect that this hydrogel-tissue mimic may be a promising preclinical model to evaluate topical or transdermal drug delivery systems with complex microarchitectures.
Mazensky, David; Petrovova, Eva; Danko, Jan
2013-01-01
The aim of this study was to describe the possible variations in the connection between the internal venous vertebral system and the cranial vena cava in rabbit using corrosion technique. The study was carried out on 40 adult New Zealand white rabbits. The venous system was injected by using Batson's corrosion casting kit number 17. We found the connection between the internal venous vertebral system and the cranial vena cava by means of the vertebral veins and the right azygos vein. The vertebral vein was present as independent tributary in 36 cases (90%). In the rest of the cases, it was found as being double, being triple, or forming a common trunk with other veins. The azygos vein was present as independent tributary of the cranial vena cava in 39 cases (97.5%). We found also a common trunk formed by the junction of the deep cervical vein, the right vertebral vein, and the azygos vein in one case (2.5%). The azygos vein received 6, 7, 8, or 9 pairs of dorsal intercostal veins. Documenting the anatomical variations in the rabbit will aid in the planning of future experimental studies and determining the clinical relevance on such studies.
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David Mazensky
2013-01-01
Full Text Available The aim of this study was to describe the possible variations in the connection between the internal venous vertebral system and the cranial vena cava in rabbit using corrosion technique. The study was carried out on 40 adult New Zealand white rabbits. The venous system was injected by using Batson's corrosion casting kit number 17. We found the connection between the internal venous vertebral system and the cranial vena cava by means of the vertebral veins and the right azygos vein. The vertebral vein was present as independent tributary in 36 cases (90%. In the rest of the cases, it was found as being double, being triple, or forming a common trunk with other veins. The azygos vein was present as independent tributary of the cranial vena cava in 39 cases (97.5%. We found also a common trunk formed by the junction of the deep cervical vein, the right vertebral vein, and the azygos vein in one case (2.5%. The azygos vein received 6, 7, 8, or 9 pairs of dorsal intercostal veins. Documenting the anatomical variations in the rabbit will aid in the planning of future experimental studies and determining the clinical relevance on such studies.
The NMR probe of high-Tc materials and correlated electron systems. 2. ed.
International Nuclear Information System (INIS)
Walstedt, Russell E.
2018-01-01
This new edition updates readers in three areas of NMR studies, namely, recent developments in high-T c materials, heavy fermion systems and actinide oxides are presented. The NMR probe has yielded a vast array of data for solid state materials, corresponding to different compounds, ionic sites, and nuclear species, as well as to a wide variety of experimental conditions. The last two parts of the book are completely new in this edition, while the first part has seen major updates. This edition features the latest developments for high-T c materials, especially the advances in the area of pseudogap studies are reviewed. An in depth overview of heavy fermion systems is presented in the second part, notably Kondo lattices, quantum critical points and unconventional superconductivity are areas of intense research recently and are covered extensively. Finally, valuable information from NMR studies with actinide oxides will be provided. Ongoing analysis and discussion of NMR data have resulted in a wealth of important insights into the physics of these exotic systems. The aims of this monograph are manifold. First, it reviews NMR methodology as it has been applied to the different studies. This is addressed to NMR practitioners and to physics laypersons alike. Next, it presents a review of NMR measurements and the wide variety of phenomena which they represent. The third phase is to recount the theoretical model calculations and other proposals which have been put forward to account for these data.
Correlations between phase behaviors and ionic conductivities of (ionic liquid + alcohol) systems
International Nuclear Information System (INIS)
Park, Nam Ku; Bae, Young Chan
2010-01-01
To understand the basic properties of ionic liquids (ILs), we examined the phase behavior and ionic conductivity characteristics using various compositions of different ionic liquids (1-ethyl-3-methylimidazolium hexafluorophosphate [emim] [PF6] and 1-benzyl-3-methylimidazolium hexafluorophosphate [bzmim] [PF6]) in several different alcohols (ethanol, propanol, 1-butanol, 2-butanol, and hexanol). We conducted a systematic study of the impact of different factors on the phase behavior of imidazolium-based ionic liquids in alcohols. Using a new experimental method with a liquid electrolyte system, we observed that the ionic conductivity of the ionic liquid/alcohol was sensitive to the surrounding temperature. We employed Chang et al.'s thermodynamic model [Chang et al. (1997, 1998) ] based on the lattice model. The obtained co-ordinated unit parameter from this model was used to describe the phase behavior and ionic conductivities of the given system. Good agreement with experimental data of various alcohol and ILs systems was obtained in the range of interest.
Staubach, Maria
2009-09-01
This study aims to identify factors which influence and cause errors in traffic accidents and to use these as a basis for information to guide the application and design of driver assistance systems. A total of 474 accidents were examined in depth for this study by means of a psychological survey, data from accident reports, and technical reconstruction information. An error analysis was subsequently carried out, taking into account the driver, environment, and vehicle sub-systems. Results showed that all accidents were influenced by errors as a consequence of distraction and reduced activity. For crossroad accidents, there were further errors resulting from sight obstruction, masked stimuli, focus errors, and law infringements. Lane departure crashes were additionally caused by errors as a result of masked stimuli, law infringements, expectation errors as well as objective and action slips, while same direction accidents occurred additionally because of focus errors, expectation errors, and objective and action slips. Most accidents were influenced by multiple factors. There is a safety potential for Advanced Driver Assistance Systems (ADAS), which support the driver in information assimilation and help to avoid distraction and reduced activity. The design of the ADAS is dependent on the specific influencing factors of the accident type.
The NMR probe of high-T{sub c} materials and correlated electron systems. 2. ed.
Energy Technology Data Exchange (ETDEWEB)
Walstedt, Russell E. [Michigan Univ., Ann Arbor, MI (United States). Dept. of Physics
2018-03-01
This new edition updates readers in three areas of NMR studies, namely, recent developments in high-T{sub c} materials, heavy fermion systems and actinide oxides are presented. The NMR probe has yielded a vast array of data for solid state materials, corresponding to different compounds, ionic sites, and nuclear species, as well as to a wide variety of experimental conditions. The last two parts of the book are completely new in this edition, while the first part has seen major updates. This edition features the latest developments for high-T{sub c} materials, especially the advances in the area of pseudogap studies are reviewed. An in depth overview of heavy fermion systems is presented in the second part, notably Kondo lattices, quantum critical points and unconventional superconductivity are areas of intense research recently and are covered extensively. Finally, valuable information from NMR studies with actinide oxides will be provided. Ongoing analysis and discussion of NMR data have resulted in a wealth of important insights into the physics of these exotic systems. The aims of this monograph are manifold. First, it reviews NMR methodology as it has been applied to the different studies. This is addressed to NMR practitioners and to physics laypersons alike. Next, it presents a review of NMR measurements and the wide variety of phenomena which they represent. The third phase is to recount the theoretical model calculations and other proposals which have been put forward to account for these data.
Energy Technology Data Exchange (ETDEWEB)
Ning Shuang [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Bian Xiufang, E-mail: xfbian@sdu.edu.c [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Ren Zhenfeng [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan 250061 (China)
2010-09-01
Activation energy is obtained from temperature dependence of viscosities by means of a fitting to the Arrhenius equation for liquid alloys of Cu-Sb, Cu-Te, Cu-Sn and Cu-Ag systems. We found that the changing trend of activation energy curves with concentration is similar to that of liquidus in the phase diagrams. Moreover, a maximum value of activation energy is in the composition range of the intermetallic phases and a minimum value of activation energy is located at the eutectic point. The correlation between the activation energy and the phase diagrams has been further discussed.
Triarhou, Lazaros C
2007-01-01
In their Atlas of Cytoarchitectonics of the Adult Human Cerebral Cortex, Economo and Koskinas defined 54 'ground,' 76 'variant,' and 107 'modification' areas. The 107 modifications are topographically distributed as 35 frontal, 13 superior limbic, 6 insular, 18 parietal, 7 occipital, 14 temporal and 14 inferior limbic (or hippocampal). One way to make the Economo-Koskinas system more practical is to encode the complex symbol notations of the 107 cortical areas with numbers EK 1 through EK 107. The present study does that, and it further correlates Economo-Koskinas areas with Brodmann areas, based on an overview of the classical and modern neurohistological literature. Copyright (c) 2007 S. Karger AG, Basel.
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JULIANA ALTAFIN GALLI
Full Text Available ABSTRACT The objective of this research was evaluate the damage caused by the yellow beetle on 85 guava accessions and correlations of the damage with the climatological elements and the production of fruit in an orchard of guava conducted in organic system. Ten leaves by access were analyzed containing the injury of insect attack. Each leaf had its foliar area measured by leaf area meter and, after obtaining the total area, the leaf was covered with duct tape, and measure again. The averages were compared by Scott-Knott test at 5% probability. The 15 accessions with highest average damage had the data submitted to the correlation with the minimum and maximum temperature, precipitation and relative humidity. The production was obtained by the number of fruits/plant. The damages are negatively correlated with the mean relative humidity of 7:00h (local time in the period of 14 days prior to the assessments, and negatively affect production. The accessions Saito, L4P16, Monte Alto Comum 1 and L5P19 are promising in organic agriculture, for presenting good production and minor damage to insect attack, when compared to others.
Tsuchimochi, Takashi
2015-10-14
Spin-flip approaches capture static correlation with the same computational scaling as the ordinary single reference methods. Here, we extend spin-flip configuration interaction singles (SFCIS) by projecting out intrinsic spin-contamination to make it spin-complete, rather than by explicitly complementing it with spin-coupled configurations. We give a general formalism of spin-projection for SFCIS, applicable to any spin states. The proposed method is viewed as a natural unification of SFCIS and spin-projected CIS to achieve a better qualitative accuracy at a low computational cost. While our wave function ansatz is more compact than previously proposed spin-complete SF approaches, it successfully offers more general static correlation beyond biradicals without sacrificing good quantum numbers. It is also shown that our method is invariant with respect to open-shell orbital rotations, due to the uniqueness of spin-projection. We will report benchmark calculations to demonstrate its qualitative performance on strongly correlated systems, including conical intersections that appear both in ground-excited and excited-excited degeneracies.
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Maria de Sousa
1992-01-01
Full Text Available This paper is written in the context of our changing preception of the immunological system as a system with possible biological roles exceding the prevailung view of a system concerned principally with the defense against external pathogens. The view discussed here relates the immunological system inextricably to the metabolism of iron, the circulation of the blood and the resolution of the evolutionary paradox created by oxygen and iron. Indirect evidence for this inextricable relationship between the two systems can be derived from the discrepancy between the theoretical quasi-impossibility of the existence of an iron deficiency state in the adult and the reality of the WHO numbers of people in the world with iron deficiency anemia. With mounting evidence that TNF, IL-1, and T lymphocyte cytokines affect hemopoieisis and iron metabolism it is possible that the reported discrepancy is a reflection of that inextricable interdependence between the two systems in the face of infection. Further direct evidence for a relationship between T cell subset numbers and iron metabolism is presented from the results of a study of T cell populations in patients with hereditary hemochromatosis. The recent finding of a correlation between low CD8+ lymphocite numbers, liver demage associated with HCVpositivity and severity of iron overload in B-thalassemia major patients (umpublished data of RW Grandy; P. Giardina, M. Hilgartner concludes this review.