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https://www.readbyqxmd.com/read/28340406/a-local-adjustment-strategy-for-the-initialization-of-dynamic-causal-modelling-to-infer-effective-connectivity-in-brain-epileptic-structures
#1
Wentao Xiang, Ahmad Karfoul, Huazhong Shu, Régine Le Bouquin Jeannès
This paper addresses the question of effective connectivity in the human cerebral cortex in the context of epilepsy. Among model based approaches to infer brain connectivity, spectral Dynamic Causal Modelling is a conventional technique for which we propose an alternative to estimate cross spectral density. The proposed strategy we investigated tackles the sub-estimation of the free energy using the well-known variational Expectation-Maximization algorithm highly sensitive to the initialization of the parameters vector by a permanent local adjustment of the initialization process...
March 7, 2017: Computers in Biology and Medicine
https://www.readbyqxmd.com/read/28340243/finite-time-parametric-identification-for-the-model-representing-the-metabolic-and-genetic-regulatory-effects-of-sequential-aerobic-respiration-and-anaerobic-fermentation-processes-in-escherichia-coli
#2
Alfonso Sepúlveda-Gálvez, Jesús Agustín Badillo-Corona, Isaac Chairez
Mathematical modelling applied to biological systems allows for the inferring of changes in the dynamic behaviour of organisms associated with variations in the environment. Models based on ordinary differential equations are most commonly used because of their ability to describe the mechanisms of biological systems such as transcription. The disadvantage of using this approach is that there is a large number of parameters involved and that it is difficult to obtain them experimentally. This study presents an algorithm to obtain a finite-time parameter characterization of the model used to describe changes in the metabolic behaviour of Escherichia coli associated with environmental changes...
March 17, 2017: Mathematical Medicine and Biology: a Journal of the IMA
https://www.readbyqxmd.com/read/28339260/dynamic-chiral-magnetic-effect-and-faraday-rotation-in-macroscopically-disordered-helical-metals
#3
J Ma, D A Pesin
We develop an effective medium theory for electromagnetic wave propagation through gapless nonuniform systems with a dynamic chiral magnetic effect. The theory allows us to calculate macroscopic-disorder-induced corrections to the values of optical, as well as chiral magnetic conductivities. In particular, we show that spatial fluctuations of the optical conductivity induce corrections to the effective value of the chiral magnetic conductivity. The absolute value of the effect varies strongly depending on the system parameters, but yields the leading frequency dependence of the polarization rotation and circular dichroism signals...
March 10, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28339231/chiral-dark-sector
#4
Raymond T Co, Keisuke Harigaya, Yasunori Nomura
We present a simple and natural dark sector model in which dark matter particles arise as composite states of hidden strong dynamics and their stability is ensured by accidental symmetries. The model has only a few free parameters. In particular, the gauge symmetry of the model forbids the masses of dark quarks, and the confinement scale of the dynamics provides the unique mass scale of the model. The gauge group contains an Abelian symmetry U(1)_{D}, which couples the dark and standard model sectors through kinetic mixing...
March 10, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28339221/open-systems-with-error-bounds-spin-boson-model-with-spectral-density-variations
#5
F Mascherpa, A Smirne, S F Huelga, M B Plenio
In the study of open quantum systems, one of the most common ways to describe environmental effects on the reduced dynamics is through the spectral density. However, in many models this object cannot be computed from first principles and needs to be inferred on phenomenological grounds or fitted to experimental data. Consequently, some uncertainty regarding its form and parameters is unavoidable; this in turn calls into question the accuracy of any theoretical predictions based on a given spectral density. Here, we focus on the spin-boson model as a prototypical open quantum system, find two error bounds on predicted expectation values in terms of the spectral density variation considered, and state a sufficient condition for the strongest one to apply...
March 10, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28335569/a-quantitative-risk-assessment-model-involving-frequency-and-threat-degree-under-line-of-business-services-for-infrastructure-of-emerging-sensor-networks
#6
Xu Jing, Hanwen Hu, Huijun Yang, Man Ho Au, Shuqin Li, Naixue Xiong, Muhammad Imran, Athanasios V Vasilakos
The prospect of Line-of-Business Services (LoBSs) for infrastructure of Emerging Sensor Networks (ESNs) is exciting. Access control remains a top challenge in this scenario as the service provider's server contains a lot of valuable resources. LoBSs' users are very diverse as they may come from a wide range of locations with vastly different characteristics. Cost of joining could be low and in many cases, intruders are eligible users conducting malicious actions. As a result, user access should be adjusted dynamically...
March 21, 2017: Sensors
https://www.readbyqxmd.com/read/28335297/rotation-of-magnetization-derived-from-brownian-relaxation-in-magnetic-fluids-of-different-viscosity-evaluated-by-dynamic-hysteresis-measurements-over-a-wide-frequency-range
#7
Satoshi Ota, Ryoichi Kitaguchi, Ryoji Takeda, Tsutomu Yamada, Yasushi Takemura
The dependence of magnetic relaxation on particle parameters, such as the size and anisotropy, has been conventionally discussed. In addition, the influences of external conditions, such as the intensity and frequency of the applied field, the surrounding viscosity, and the temperature on the magnetic relaxation have been researched. According to one of the basic theories regarding magnetic relaxation, the faster type of relaxation dominates the process. However, in this study, we reveal that Brownian and Néel relaxations coexist and that Brownian relaxation can occur after Néel relaxation despite having a longer relaxation time...
September 10, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28335222/effects-of-atomization-injection-on-nanoparticle-processing-in-suspension-plasma-spray
#8
Hong-Bing Xiong, Cheng-Yu Zhang, Kai Zhang, Xue-Ming Shao
Liquid atomization is applied in nanostructure dense coating technology to inject suspended nano-size powder materials into a suspension plasma spray (SPS) torch. This paper presents the effects of the atomization parameters on the nanoparticle processing. A numerical model was developed to simulate the dynamic behaviors of the suspension droplets, the solid nanoparticles or agglomerates, as well as the interactions between them and the plasma gas. The plasma gas was calculated as compressible, multi-component, turbulent jet flow in Eulerian scheme...
May 20, 2016: Nanomaterials
https://www.readbyqxmd.com/read/28334863/consecutive-non-natural-pz-nucleobase-pairs-in-dna-impact-helical-structure-as-seen-in-50-%C3%AE-s-molecular-dynamics-simulations
#9
Robert W Molt, Millie M Georgiadis, Nigel G J Richards
Little is known about the influence of multiple consecutive 'non-standard' ( , 6-amino-5-nitro-2(1H)-pyridone, and , 2-amino-imidazo[1,2-a]-1,3,5-triazin-4(8H)-one) nucleobase pairs on the structural parameters of duplex DNA. nucleobase pairs follow standard rules for Watson-Crick base pairing but have rearranged hydrogen bonding donor and acceptor groups. Using the X-ray crystal structure as a starting point, we have modeled the motions of a DNA duplex built from a self-complementary oligonucleotide (5΄-CTTATPPPZZZATAAG-3΄) in water over a period of 50 μs and calculated DNA local parameters, step parameters, helix parameters, and major/minor groove widths to examine how the presence of multiple, consecutive nucleobase pairs might impact helical structure...
February 28, 2017: Nucleic Acids Research
https://www.readbyqxmd.com/read/28334271/a-temperature-dependent-phenology-model-for-liriomyza-huidobrensis-diptera-agromyzidae
#10
Norma Mujica, Marc Sporleder, Pablo Carhuapoma, Jürgen Kroschel
Liriomyza huidobrensis (Blanchard) is an economically important and highly polyphagous worldwide pest. To establish a temperature-dependent phenology model, essential for understanding the development and growth of the pest population under a variety of climates and as part of a pest risk analysis, L. huidobrensis life-table data were collected under laboratory conditions at seven constant temperatures on its host faba bean (Vicia faba L.). Several nonlinear equations were fitted to each life stage to model the temperature-dependent population growth and species life history and finally compile an overall temperature-dependent pest phenology model using the Insect Life Cycle Modeling (ILCYM) software...
March 8, 2017: Journal of Economic Entomology
https://www.readbyqxmd.com/read/28334145/combined-effects-of-thinning-and-decline-on-fine-root-dynamics-in-a-quercus-robur-l-forest-adjoining-the-italian-pre-alps
#11
E Mosca, L Montecchio, G Barion, C Dal Cortivo, T Vamerali
Aims: Oak decline is a complex phenomenon, characterized by symptoms of canopy transparency, bark cracks and root biomass reduction. Root health status is one of the first stress indicators, and root turnover is a key process in plant adaptation to unfavourable conditions. In this study, the combined effects of decline and thinning were evaluated on fine root dynamics in an oak forest adjoining the Italian Pre-Alps by comparison of acute declining trees with non-declining trees, both with and without thinning treatment of surrounding trees...
February 28, 2017: Annals of Botany
https://www.readbyqxmd.com/read/28333937/variability-in-age-and-size-at-maturation-reproductive-longevity-and-long-term-growth-dynamics-for-kemp-s-ridley-sea-turtles-in-the-gulf-of-mexico
#12
Larisa Avens, Lisa R Goshe, Lewis Coggins, Donna J Shaver, Ben Higgins, Andre M Landry, Rhonda Bailey
Effective management of protected sea turtle populations requires knowledge not only of mean values for demographic and life-history parameters, but also temporal and spatial trends, variability, and underlying causes. For endangered Kemp's ridley sea turtles (Lepidochelys kempii), the need for baseline information of this type has been emphasized during attempts to understand causes underlying the recent truncation in the recovery trajectory for nesting females. To provide insight into variability in age and size at sexual maturation (ASM and SSM) and long-term growth patterns likely to influence population trends, we conducted skeletochronological analysis of humerus bones from 333 Kemp's ridleys stranded throughout the Gulf of Mexico (GOM) from 1993 to 2010...
2017: PloS One
https://www.readbyqxmd.com/read/28333929/the-rise-and-fall-of-rabies-in-japan-a-quantitative-history-of-rabies-epidemics-in-osaka-prefecture-1914-1933
#13
Aiko Kurosawa, Kageaki Tojinbara, Hazumu Kadowaki, Katie Hampson, Akio Yamada, Kohei Makita
Japan has been free from rabies since the 1950s. However, during the early 1900s several large-scale epidemics spread throughout the country. Here we investigate the dynamics of these epidemics between 1914 and 1933 in Osaka Prefecture, using archival data including newspapers. The association between dog rabies cases and human population density was investigated using Mixed-effects models and epidemiological parameters such as the basic reproduction number (R0), the incubation and infectious period and the serial interval were estimated...
March 23, 2017: PLoS Neglected Tropical Diseases
https://www.readbyqxmd.com/read/28333652/survivability-modeling-and-resource-planning-for-self-repairing-reconfigurable-device-fabrics
#14
Rashad S Oreifej, Rawad Al-Haddad, Ramtin Zand, Rizwan A Ashraf, Ronald F DeMara
A resilient system design problem is formulated as the quantification of uncommitted reconfigurable resources required for a system of components to survive its lifetime within mission availability specifications. We show that this survivability metric can be calculated according to the residual functionality obtained from pools of dynamically configurable elements constituting the amorphous resource pool (ARP). The ARP is depleted based on the failure rate to replenish the functionality lost in a reconfigurable fabric due to the occurrence of permanent faults during the mission lifetime...
March 21, 2017: IEEE Transactions on Cybernetics
https://www.readbyqxmd.com/read/28333171/dual-dimensional-nanostructures-with-highly-durable-non-wetting-properties-under-dynamic-and-underwater-conditions
#15
Seunghyeon Baek, Wuseok Kim, Sangmin Jeon, Kijung Yong
Non-wetting states with high durability under both dynamic and underwater conditions are very desirable for practical applications of superhydrophobic surfaces in various fields. Despite increasing demands for this dual stability of non-wetting surfaces, studies investigating both the impact dynamics and underwater stability are very rare. In the current study, we performed water droplet impact dynamics and underwater stability studies using ZnO/Si hierarchical nanostructures (HNs) as a model system. The effects of the surface structure on the non-wetting states under dynamic conditions were first studied by comparing various surface structures, such as ZnO nanowires (NWs), Si microposts (MPs), ZnO/Si HNs with controlled MP interspacings, and lotus leaf (LL)...
March 23, 2017: Nanoscale
https://www.readbyqxmd.com/read/28332621/evolution-analysis-of-euv-radiation-from-laser-produced-tin-plasmas-based-on-a-radiation-hydrodynamics-model
#16
M G Su, Q Min, S Q Cao, D X Sun, P Hayden, G O'Sullivan, C Z Dong
One of fundamental aims of extreme ultraviolet (EUV) lithography is to maximize brightness or conversion efficiency of laser energy to radiation at specific wavelengths from laser produced plasmas (LPPs) of specific elements for matching to available multilayer optical systems. Tin LPPs have been chosen for operation at a wavelength of 13.5 nm. For an investigation of EUV radiation of laser-produced tin plasmas, it is crucial to study the related atomic processes and their evolution so as to reliably predict the optimum plasma and experimental conditions...
March 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28332595/mechanistic-platform-knowledge-of-concomitant-sugar-uptake-in-escherichia-coli-bl21-de3-strains
#17
David J Wurm, Johanna Hausjell, Sophia Ulonska, Christoph Herwig, Oliver Spadiut
When producing recombinant proteins, the use of Escherichia coli strain BL21(DE3) in combination with the T7-based pET-expression system is often the method of choice. In a recent study we introduced a mechanistic model describing the correlation of the specific glucose uptake rate (qs,glu) and the corresponding maximum specific lactose uptake rate (qs,lac,max) for a pET-based E. coli BL21(DE3) strain producing a single chain variable fragment (scFv). We showed the effect of qs,lac,max on productivity and product location underlining its importance for recombinant protein production...
March 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28332407/unsteady-computational-fluid-dynamics-in-front-crawl-swimming
#18
Mathias Samson, Anthony Bernard, Tony Monnet, Patrick Lacouture, Laurent David
The development of codes and power calculations currently allows the simulation of increasingly complex flows, especially in the turbulent regime. Swimming research should benefit from these technological advances to try to better understand the dynamic mechanisms involved in swimming. An unsteady Computational Fluid Dynamics (CFD) study is conducted in crawl, in order to analyse the propulsive forces generated by the hand and forearm. The k-ω SST turbulence model and an overset grid method have been used...
March 23, 2017: Computer Methods in Biomechanics and Biomedical Engineering
https://www.readbyqxmd.com/read/28332315/significant-increase-of-flow-kinetic-energy-in-nonresponders-patients-to-cardiac-resynchronization-therapy
#19
Sara Cimino, Dino Palombizio, Francesco Cicogna, Donatella Cantisani, Manuela Reali, Domenico Filomena, Valentina Petronilli, Carlo Iacoboni, Luciano Agati
BACKGROUNDS: It's still unclear if different patterns of intraventricular flow dynamics may be detected in patients nonresponders to cardiac resynchronization therapy (CRT) as compared to responders ones. Aim of this study was to evaluate the characteristics of left ventricular (LV) flow dynamics 6-months after CRT to identify Echo-particle imaging velocity (PIV) patterns were more frequently detected in nonresponders patients. METHODS: Thirty-two patients with dilated cardiomyopathy, undergoing CRT, were enrolled in this study...
March 23, 2017: Echocardiography
https://www.readbyqxmd.com/read/28332138/benzo-a-pyrene-exposure-causes-genotoxic-and-biochemical-changes-in-the-midge-larvae-of-chironomus-sancticaroli-strixino-strixino-diptera-chironomidae
#20
M Vicentini, G S Morais, D Rebechi-Baggio, V S Richardi, G S Santos, M M Cestari, M A Navarro-Silva
Benzo(a)pyrene (BaP) is a carcinogenic polycyclic aromatic hydrocarbon, also found in nature due to human activities. BaP adheres to sediments showing toxic effects on benthic organisms, including midge larvae of the family Chironomidae. We tested for toxic effects of benzo(a)pyrene on Chironomus sancticaroli Strixino & Strixino 1981 using biochemical and genotoxic biomarkers, to identify changes in metabolic and antioxidant pathways, besides neurotoxic and DNA damage. Enzyme activity was compared by exposing larvae to four nominal concentrations (0...
March 22, 2017: Neotropical Entomology
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