Spin injection and spin transport in paramagnetic insulators

DOE PAGES

Okamoto, Satoshi

2016-02-22

We investigate the spin injection and the spin transport in paramagnetic insulators described by simple Heisenberg interactions using auxiliary particle methods. Some of these methods allow access to both paramagnetic states above magnetic transition temperatures and magnetic states at low temperatures. It is predicted that the spin injection at an interface with a normal metal is rather insensitive to temperatures above the magnetic transition temperature. On the other hand below the transition temperature, it decreases monotonically and disappears at zero temperature. We also analyze the bulk spin conductance. We show that the conductance becomes zero at zero temperature as predictedmore » by linear spin wave theory but increases with temperature and is maximized around the magnetic transition temperature. These findings suggest that the compromise between the two effects determines the optimal temperature for spintronics applications utilizing magnetic insulators.« less

Magnetic preferential orientation of metal oxide superconducting materials

DOEpatents

Capone, D.W.; Dunlap, B.D.; Veal, B.W.

1990-07-17

A superconductor comprised of a polycrystalline metal oxide such as YBa[sub 2]Cu[sub 3]O[sub 7[minus]X] (where 0 < X < 0.5) exhibits superconducting properties and is capable of conducting very large current densities. By aligning the two-dimensional Cu-O layers which carry the current in the superconducting state in the a- and b-directions, i.e., within the basal plane, a high degree of crystalline axes alignment is provided between adjacent grains permitting the conduction of high current densities. The highly anisotropic diamagnetic susceptibility of the polycrystalline metal oxide material permits the use of an applied magnetic field to orient the individual crystals when in the superconducting state to substantially increase current transport between adjacent grains. In another embodiment, the anisotropic paramagnetic susceptibility of rare-earth ions substituted into the oxide material is made use of as an applied magnetic field orients the particles in a preferential direction. This latter operation can be performed with the material in the normal (non-superconducting) state. 4 figs.

Monolithic quasi-solid-state dye-sensitized solar cells based on graphene-modified mesoscopic carbon-counter electrodes

NASA Astrophysics Data System (ADS)

Rong, Yaoguang; Han, Hongwei

2013-01-01

A monolithic quasi-solid-state dye-sensitized solar cell (DSSC) based on graphene-modified mesoscopic carbon-counter electrode is developed. A TiO2-working electrode layer, ZrO2 spacer layer, and carbon counter electrode layer were constructed on a single conducting glass substrate by screen printing. The quasi-solid-state polymer gel electrolyte employed a polymer composite as the gelator, and effectively infiltrated the porous layers. Fabricated with normal carbon-counter electrode (NC-CE) containing graphite and carbon black, the DSSC had a power conversion efficiency (PCE) of 5.09% with the fill factor of 0.63 at 100 mW cm-2 AM1.5 illumination. When the NC-CE was modified with graphene sheets, the PCE and fill factor were enhanced to 6.27% and 0.71, respectively. This improvement indicates excellent conductivity and high electrocatalytic activity of the graphene sheets, which have been considered as a promising platinum-free electrode material for DSSCs.

Magnetic preferential orientation of metal oxide superconducting materials

DOEpatents

Capone, Donald W.; Dunlap, Bobby D.; Veal, Boyd W.

1990-01-01

A superconductor comprised of a polycrystalline metal oxide such as YBa.sub.2 Cu.sub.3 O.sub.7-X (where 0

Non-local electron transport through normal and topological ladder-like atomic systems

NASA Astrophysics Data System (ADS)

Kurzyna, Marcin; Kwapiński, Tomasz

2018-05-01

We propose a locally protected ladder-like atomic system (nanoconductor) on a substrate that is insensitive to external perturbations. The system corresponds to coupled atomic chains fabricated on different surfaces. Electron transport properties of such conductors are studied theoretically using the model tight-binding Su-Schriffer-Hegger (SSH) Hamiltonian and Green's function formalism. We have found that the conductance of the system is almost insensitive to single adatoms and oscillates as a function of the side chain length with very large periods. Non-local character of the electron transport was observed also for topological SSH chains where nontrivial end states survive in the presence of disturbances as well as for different substrates. We have found that the careful inspection of the density of states or charge waves can provide the information about the atom energy levels and hopping amplitudes. Moreover, the ladder-like geometry allows one to distinguish between normal and topological zero-energy states. It is important that topological chains do not reveal Friedel oscillations which are observed in non-topological chains.

Electrical conductivity measurement of excised human metastatic liver tumours before and after thermal ablation.

PubMed

Haemmerich, Dieter; Schutt, David J; Wright, Andrew W; Webster, John G; Mahvi, David M

2009-05-01

We measured the ex vivo electrical conductivity of eight human metastatic liver tumours and six normal liver tissue samples from six patients using the four electrode method over the frequency range 10 Hz to 1 MHz. In addition, in a single patient we measured the electrical conductivity before and after the thermal ablation of normal and tumour tissue. The average conductivity of tumour tissue was significantly higher than normal tissue over the entire frequency range (from 4.11 versus 0.75 mS cm(-1) at 10 Hz, to 5.33 versus 2.88 mS cm(-1) at 1 MHz). We found no significant correlation between tumour size and measured electrical conductivity. While before ablation tumour tissue had considerably higher conductivity than normal tissue, the two had similar conductivity throughout the frequency range after ablation. Tumour tissue conductivity changed by +25% and -7% at 10 Hz and 1 MHz after ablation (0.23-0.29 at 10 Hz, and 0.43-0.40 at 1 MHz), while normal tissue conductivity increased by +270% and +10% at 10 Hz and 1 MHz (0.09-0.32 at 10 Hz and 0.37-0.41 at 1 MHz). These data can potentially be used to differentiate tumour from normal tissue diagnostically.

Single-cell RNA sequencing identifies diverse roles of epithelial cells in idiopathic pulmonary fibrosis

PubMed Central

Mizuno, Takako; Sridharan, Anusha; Du, Yina; Guo, Minzhe; Wikenheiser-Brokamp, Kathryn A.; Perl, Anne-Karina T.; Funari, Vincent A.; Gokey, Jason J.; Stripp, Barry R.; Whitsett, Jeffrey A.

2016-01-01

Idiopathic pulmonary fibrosis (IPF) is a lethal interstitial lung disease characterized by airway remodeling, inflammation, alveolar destruction, and fibrosis. We utilized single-cell RNA sequencing (scRNA-seq) to identify epithelial cell types and associated biological processes involved in the pathogenesis of IPF. Transcriptomic analysis of normal human lung epithelial cells defined gene expression patterns associated with highly differentiated alveolar type 2 (AT2) cells, indicated by enrichment of RNAs critical for surfactant homeostasis. In contrast, scRNA-seq of IPF cells identified 3 distinct subsets of epithelial cell types with characteristics of conducting airway basal and goblet cells and an additional atypical transitional cell that contributes to pathological processes in IPF. Individual IPF cells frequently coexpressed alveolar type 1 (AT1), AT2, and conducting airway selective markers, demonstrating “indeterminate” states of differentiation not seen in normal lung development. Pathway analysis predicted aberrant activation of canonical signaling via TGF-β, HIPPO/YAP, P53, WNT, and AKT/PI3K. Immunofluorescence confocal microscopy identified the disruption of alveolar structure and loss of the normal proximal-peripheral differentiation of pulmonary epithelial cells. scRNA-seq analyses identified loss of normal epithelial cell identities and unique contributions of epithelial cells to the pathogenesis of IPF. The present study provides a rich data source to further explore lung health and disease. PMID:27942595

Quasi One-Dimensional Unsteady Modeling of External Compression Supersonic Inlets

NASA Technical Reports Server (NTRS)

Kopasakis, George; Connolly, Joseph W.; Kratz, Jonathan

2012-01-01

The AeroServoElasticity task under the NASA Supersonics Project is developing dynamic models of the propulsion system and the vehicle in order to conduct research for integrated vehicle dynamic performance. As part of this effort, a nonlinear quasi 1-dimensional model of an axisymmetric external compression supersonic inlet is being developed. The model utilizes compressible flow computational fluid dynamics to model the internal inlet segment as well as the external inlet portion between the cowl lip and normal shock, and compressible flow relations with flow propagation delay to model the oblique shocks upstream of the normal shock. The external compression portion between the cowl-lip and the normal shock is also modeled with leaking fluxes crossing the sonic boundary, with a moving CFD domain at the normal shock boundary. This model has been verified in steady state against tunnel inlet test data and it s a first attempt towards developing a more comprehensive model for inlet dynamics.

State-dependent anisotrophy: Comparison of quasi-analytical solutions with stochastic results for steady gravity drainage

USGS Publications Warehouse

Green, Timothy R.; Freyberg, David L.

1995-01-01

Anisotropy in large-scale unsaturated hydraulic conductivity of layered soils changes with the moisture state. Here, state-dependent anisotropy is computed under conditions of large-scale gravity drainage. Soils represented by Gardner's exponential function are perfectly stratified, periodic, and inclined. Analytical integration of Darcy’s law across each layer results in a system of nonlinear equations that is solved iteratively for capillary suction at layer interfaces and for the Darcy flux normal to layering. Computed fluxes and suction profiles are used to determine both upscaled hydraulic conductivity in the principal directions and the corresponding “state-dependent” anisotropy ratio as functions of the mean suction. Three groups of layered soils are analyzed and compared with independent predictions from the stochastic results of Yeh et al. (1985b). The small-perturbation approach predicts appropriate behaviors for anisotropy under nonarid conditions. However, the stochastic results are limited to moderate values of mean suction; this limitation is linked to a Taylor series approximation in terms of a group of statistical and geometric parameters. Two alternative forms of the Taylor series provide upper and lower bounds for the state-dependent anisotropy of relatively dry soils.

The Initiation of Smooth Pursuit is Delayed in Anisometropic Amblyopia.

PubMed

Raashid, Rana Arham; Liu, Ivy Ziqian; Blakeman, Alan; Goltz, Herbert C; Wong, Agnes M F

2016-04-01

Several behavioral studies have shown that the reaction times of visually guided movements are slower in people with amblyopia, particularly during amblyopic eye viewing. Here, we tested the hypothesis that the initiation of smooth pursuit eye movements, which are responsible for accurately keeping moving objects on the fovea, is delayed in people with anisometropic amblyopia. Eleven participants with anisometropic amblyopia and 14 visually normal observers were asked to track a step-ramp target moving at ±15°/s horizontally as quickly and as accurately as possible. The experiment was conducted under three viewing conditions: amblyopic/nondominant eye, binocular, and fellow/dominant eye viewing. Outcome measures were smooth pursuit latency, open-loop gain, steady state gain, and catch-up saccade frequency. Participants with anisometropic amblyopia initiated smooth pursuit significantly slower during amblyopic eye viewing (206 ± 20 ms) than visually normal observers viewing with their nondominant eye (183 ± 17 ms, P = 0.002). However, mean pursuit latency in the anisometropic amblyopia group during binocular and monocular fellow eye viewing was comparable to the visually normal group. Mean open-loop gain, steady state gain, and catch-up saccade frequency were similar between the two groups, but participants with anisometropic amblyopia exhibited more variable steady state gain (P = 0.045). This study provides evidence of temporally delayed smooth pursuit initiation in anisometropic amblyopia. After initiation, the smooth pursuit velocity profile in anisometropic amblyopia participants is similar to visually normal controls. This finding differs from what has been observed previously in participants with strabismic amblyopia who exhibit reduced smooth pursuit velocity gains with more catch-up saccades.

Superconducting and Normal State Properties of OsB2*

NASA Astrophysics Data System (ADS)

Singh, Yogesh; Niazi, A.; Zong, X.; Suh, B. J.; Vannette, M. W.; Prozorov, R.; Johnston, D. C.

2007-03-01

OsB2 is a layered superhard metallic material that was found to superconduct below Tc= 2.1 K.^1 We report the first detailed measurements of the static and dynamic magnetic susceptibilities χ, electrical resistivity, heat capacity Cp, penetration depth, and ^11B NMR on OsB2 to characterize its superconducting and normal state properties. The results confirm that OsB2 is a bulk superconductor below Tc= 2.1 K@. Its properties can be described by a close to weak-coupling s-wave BCS model with an electron-phonon coupling constant λ= 0.4--0.5, δ(0)/(kBTc) 1.9, a small Ginzburg-Landau parameter κ of order 5 or less, and a small zero-temperature critical magnetic field of roughly 500 Oe. The ^11B NMR measurements in the normal state show a nuclear spin-lattice relaxation time T1= 2.1 s at room temperature and a Korringa law with T1T = 610 s.K at lower T, and a correspondingly small T-independent Knight shift. These results indicate a small s character of the conduction electron wave function at the B site at the Fermi level. Our results will be compared to corresponding data for MgB2.1. J. K. Vandenberg et al., Mater. Res. Bull. 10, 889 (1975).^*Supported by the USDOE under Contract No. W-7405-Eng-82. Permanent address: Dept. Phys., The Catholic Univ. Korea.

[Aberrant topological properties of whole-brain functional network in chronic right-sided sensorineural hearing loss: a resting-state functional MRI study].

PubMed

Zhang, Lingling; Liu, Bin; Xu, Yangwen; Yang, Ming; Feng, Yuan; Huang, Yaqing; Huan, Zhichun; Hou, Zhaorui

2015-02-03

To investigate the topological properties of the functional brain network in unilateral sensorineural hearing loss patients. In this study, we acquired resting-state BOLD- fMRI data from 19 right-sided SNHL patients and 31 healthy controls with normal hearing and constructed their whole brain functional networks. Two-sample two-tailed t-tests were performed to investigate group differences in topological parameters between the USNHL patients and the controls. Partial correlation analysis was conducted to determine the relationships between the network metrics and USNHL-related variables. Both USNHL patients and controls exhibited small-word architecture in their brain functional networks within the range 0. 1 - 0. 2 of sparsity. Compared to the controls, USNHL patients showed significant increase in characteristic path length and normalized characteristic path length, but significant decrease in global efficiency. Clustering coefficient, local efficiency and normalized clustering coefficient demonstrated no significant difference. Furthermore, USNHL patients exhibited no significant association between the altered network metrics and the duration of USNHL or the severity of hearing loss. Our results indicated the altered topological properties of whole brain functional networks in USNHL patients, which may help us to understand pathophysiologic mechanism of USNHL patients.

To Be Free and Normal: Addiction, Governance, and the Therapeutics of Buprenorphine.

PubMed

Harris, Shana

2015-12-01

Methadone maintenance has dominated opiate addiction treatment in the United States for decades. Since 2002, opiate addiction has also been treated in general medical settings with a substance called buprenorphine. Based on interviews and participant observation conducted in northern California, this article analyzes how discourses of freedom and normalcy in patient and provider narratives reflect and affect experiences with this treatment modality. I discuss how buprenorphine treatment, in contrast to methadone maintenance, offers patients and providers a greater sense of autonomy and flexibility in how they receive and deliver treatment. It presents them with new obligations, responsibilities, and choices around care and conduct. It simultaneously perpetuates and shapes a desire to be "free" and "normal." I argue that the therapeutics of buprenorphine govern patients and providers through this desire for freedom and normalcy. Buprenorphine is thus a technology of governmentality that extends neoliberal discourses and values and produces self-governing subjects. © 2015 by the American Anthropological Association.

Quantum transport through 3D Dirac materials

NASA Astrophysics Data System (ADS)

Salehi, M.; Jafari, S. A.

2015-08-01

Bismuth and its alloys provide a paradigm to realize three dimensional materials whose low-energy effective theory is given by Dirac equation in 3+1 dimensions. We study the quantum transport properties of three dimensional Dirac materials within the framework of Landauer-Büttiker formalism. Charge carriers in normal metal satisfying the Schrödinger equation, can be split into four-component with appropriate matching conditions at the boundary with the three dimensional Dirac material (3DDM). We calculate the conductance and the Fano factor of an interface separating 3DDM from a normal metal, as well as the conductance through a slab of 3DDM. Under certain circumstances the 3DDM appears transparent to electrons hitting the 3DDM. We find that electrons hitting the metal-3DDM interface from metallic side can enter 3DDM in a reversed spin state as soon as their angle of incidence deviates from the direction perpendicular to interface. However the presence of a second interface completely cancels this effect.

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

Salehi, M.; Jafari, S.A., E-mail: jafari@physics.sharif.edu; Center of Excellence for Complex Systems and Condensed Matter

Bismuth and its alloys provide a paradigm to realize three dimensional materials whose low-energy effective theory is given by Dirac equation in 3+1 dimensions. We study the quantum transport properties of three dimensional Dirac materials within the framework of Landauer–Büttiker formalism. Charge carriers in normal metal satisfying the Schrödinger equation, can be split into four-component with appropriate matching conditions at the boundary with the three dimensional Dirac material (3DDM). We calculate the conductance and the Fano factor of an interface separating 3DDM from a normal metal, as well as the conductance through a slab of 3DDM. Under certain circumstances themore » 3DDM appears transparent to electrons hitting the 3DDM. We find that electrons hitting the metal-3DDM interface from metallic side can enter 3DDM in a reversed spin state as soon as their angle of incidence deviates from the direction perpendicular to interface. However the presence of a second interface completely cancels this effect.« less

The Calderón problem with corrupted data

NASA Astrophysics Data System (ADS)

Caro, Pedro; Garcia, Andoni

2017-08-01

We consider the inverse Calderón problem consisting of determining the conductivity inside a medium by electrical measurements on its surface. Ideally, these measurements determine the Dirichlet-to-Neumann map and, therefore, one usually assumes the data to be given by such a map. This situation corresponds to having access to infinite-precision measurements, which is totally unrealistic. In this paper, we study the Calderón problem assuming the data to contain measurement errors and provide formulas to reconstruct the conductivity and its normal derivative on the surface. Additionally, we state the rate convergence of the method. Our approach is theoretical and has a stochastic flavour.

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

Ghadkolai, Milad Azami; Creager, Stephen; Nanda, Jagjit

Lithium titanate (Li 4Ti 5O 12) powders with and without molybdenum doping (LTO and MoLTO respectively) were synthesized by a solid-state method and used to fabricate electrodes on Cu foil using a normal tape-cast method and a novel freeze-tape-cast method. Modest molybdenum doping produces a significant electronic conductivity increase (e.g. 1 mS cm -1 for MoLTO vs 10 -7 mS cm -1 for LTO) that is thought to reflect a partial Ti 4+ reduction to Ti 3+ with charge compensation by the Mo 6+ dopant, producing a stable mixed-valent Ti 4+/3+ state. Freeze-tape-cast electrodes were fabricated by a variant ofmore » the normal tape-cast method that includes a rapid freezing step in which the solvent in the Cu-foil-supported slurry is rapidly frozen on a cold finger then subsequently sublimed to create unidirectional columnar macropores in the electrode. The resulting electrodes exhibit high porosity and low tortuosity which enhances electrolyte accessibility throughout the full electrode thickness. Freeze-tape-cast electrodes subjected to galvanostatic charge-discharge testing as cathodes in cells vs. a lithium metal anode exhibit higher specific capacity and lower capacity loss at high discharge rates compared with normal-tape-cast electrodes of the same mass loading, despite the fact that the freeze-tape-cast electrodes are nearly twice as thick as the normal tape cast electrodes.« less

Steady-state chlorophyll fluorescence (Fs) measurements as a tool to follow variations of net CO2 assimilation and stomatal conductance during water-stress in C3 plants.

PubMed

Flexas, Jaume; Escalona, José Mariano; Evain, Sebastian; Gulías, Javier; Moya, Ismaël; Osmond, Charles Barry; Medrano, Hipólito

2002-02-01

Water stress experiments were performed with grapevines (Vitis vinifera L.) and other C3 plants in the field, in potted plants in the laboratory, and with detached leaves. It was found that, in all cases, the ratio of steady state chlorophyll fluorescence (Fs) normalized to dark-adapted intrinsic fluorescence (Fo) inversely correlated with non-photochemical quenching (NPQ). Also, at high irradiance, the ratio Fs/Fo was positively correlated with CO2 assimilation in air, with electron transport rate calculated from fluorescence, and with stomatal conductance, but no clear correlation was observed with qP. The significance of these relationships is discussed. The ratio Fs/Fo, measured with a portable instrument (PAM-2000) or with a remote sensing FIPAM system, provides a good method for the early detection of water stress, and may become a useful guide to irrigation requirements.

Two Salt Bridges Differentially Contribute to the Maintenance of Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Channel Function*

PubMed Central

Cui, Guiying; Freeman, Cody S.; Knotts, Taylor; Prince, Chengyu Z.; Kuang, Christopher; McCarty, Nael A.

2013-01-01

Previous studies have identified two salt bridges in human CFTR chloride ion channels, Arg352-Asp993 and Arg347-Asp924, that are required for normal channel function. In the present study, we determined how the two salt bridges cooperate to maintain the open pore architecture of CFTR. Our data suggest that Arg347 not only interacts with Asp924 but also interacts with Asp993. The tripartite interaction Arg347-Asp924-Asp993 mainly contributes to maintaining a stable s2 open subconductance state. The Arg352-Asp993 salt bridge, in contrast, is involved in stabilizing both the s2 and full (f) open conductance states, with the main contribution being to the f state. The s1 subconductance state does not require either salt bridge. In confirmation of the role of Arg352 and Asp993, channels bearing cysteines at these sites could be latched into a full open state using the bifunctional cross-linker 1,2-ethanediyl bismethanethiosulfonate, but only when applied in the open state. Channels remained latched open even after washout of ATP. The results suggest that these interacting residues contribute differently to stabilizing the open pore in different phases of the gating cycle. PMID:23709221

Manifestation of hopping conductivity and granularity within phase diagrams of LaO1-x F x BiS2, Sr1-x La x FBiS2 and related BiS2-based compounds

NASA Astrophysics Data System (ADS)

Arouca, R.; Silva Neto, M. B.; Chaves, C. M.; Nagao, M.; Watauchi, S.; Tanaka, I.; ElMassalami, M.

2017-09-01

Layered BiS 2 -based series, such as LaO 1-x F x BiS 2 and Sr 1-x La x FBiS 2 , offer ideal examples for studying normal and superconducting phase diagram of a solid solution that evolves from a nonmagnetic band-insulator parent. We constructed typical x-T phase diagrams of these systems based on events occurring in thermal evolution of their electrical resistivity, ρ(x, T) . Overall evolution of these diagrams can be rationalized in terms of (i) Mott-Efros-Shklovskii scenario which, within the semiconducting x regime (x_MIT = Mott metal-insulator transition), describes the doping influence on the thermally activated hopping conductivity. (ii) A granular metal (superconductor) scenario which, within x_MIT< x < x_solubility , describes the evolution of normal and superconducting properties in terms of conductance g, Coulomb charging energy E c and Josephson coupling J; their joint influence is usually captured within a g-\\frac{gE_c}{J}-T phase diagram. Based on analysis of the granular character of ρ(x, T) , we converted the x-T diagrams into projected g - T diagrams which, being fundamental, allow a better understanding of evolution of various granular-related properties (in particular the hallmarks of normal-state \\partialρ/\\partial T<0 feature and superconductor-insulator transition) and how such properties are influenced by x, pressure or heat treatment.

Structural Changes Fundamental to Gating of the Cystic Fibrosis Transmembrane Conductance Regulator Anion Channel Pore.

PubMed

Linsdell, Paul

2017-01-01

Cystic fibrosis is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR), an epithelial cell anion channel. Potentiator drugs used in the treatment of cystic fibrosis act on the channel to increase overall channel function, by increasing the stability of its open state and/or decreasing the stability of its closed state. The structure of the channel in either the open state or the closed state is not currently known. However, changes in the conformation of the protein as it transitions between these two states have been studied using functional investigation and molecular modeling techniques. This review summarizes our current understanding of the architecture of the transmembrane channel pore that controls the movement of chloride and other small anions, both in the open state and in the closed state. Evidence for different kinds of changes in the conformation of the pore as it transitions between open and closed states is described, as well as the mechanisms by which these conformational changes might be controlled to regulate normal channel gating. The ways that key conformational changes might be targeted by small compounds to influence overall CFTR activity are also discussed. Understanding the changes in pore structure that might be manipulated by such small compounds is key to the development of novel therapeutic strategies for the treatment of cystic fibrosis.

Control of Respiratory Motion by Hypnosis Intervention during Radiotherapy of Lung Cancer I

PubMed Central

Deng, Jie; Xie, Yaoqin

2013-01-01

The uncertain position of lung tumor during radiotherapy compromises the treatment effect. To effectively control respiratory motion during radiotherapy of lung cancer without any side effects, a novel control scheme, hypnosis, has been introduced in lung cancer treatment. In order to verify the suggested method, six volunteers were selected with a wide range of distribution of age, weight, and chest circumference. A set of experiments have been conducted for each volunteer, under the guidance of the professional hypnotist. All the experiments were repeated in the same environmental condition. The amplitude of respiration has been recorded under the normal state and hypnosis, respectively. Experimental results show that the respiration motion of volunteers in hypnosis has smaller and more stable amplitudes than in normal state. That implies that the hypnosis intervention can be an alternative way for respiratory control, which can effectively reduce the respiratory amplitude and increase the stability of respiratory cycle. The proposed method will find useful application in image-guided radiotherapy. PMID:24093100

Anomalous Normal State and Quasi Particle Transport in High-Tc Superconductors

NASA Astrophysics Data System (ADS)

Ong, N. P.

1997-03-01

The quasi-particles (qp) below Tc are much less studied compared to excitations of the normal state. The thermal conductivity tensor κ_ij provides a window on their transport properties. In YBaCuO, the large thermal Hall response allows the qp mean-free-path l to be estimated. l rises rapidly from 90 Åat Tc to over 6,000 Åat 20 K in untwinned crystals. The intense scattering rate above Tc is rapidly suppressed, leaving qp's that travel great distances at low T. In LaSrCuO, where there is substantial disorder, κ_xx varies logarithmically with field B. While the field dependence is entirely electronic, it is incompatible with scattering from vortices. κ_xx fits well to the digamma function form ψ(1/2+ fracB_0B) + ln(fracBB_0), with a T-linear field-scale B_0. Possible field destruction of a quantum interference effect or depairing effects in a d-wave superconductor will be discussed.

Sodium deficiency effect on the transport properties of La0.8Na0.2-x□xMnO3 manganites

NASA Astrophysics Data System (ADS)

Elghoul, N.; Wali, M.; Kraiem, S.; Rahmouni, H.; Dhahri, E.; Khirouni, K.

2015-12-01

Effect of sodium deficiency on the transport properties of La0.8Na0.2-x□xMnO3 manganites is investigated using impedance spectroscopy technique. In the whole explored temperature range (77-700 K), conductivity measurements show the appearance of a metal-semiconductor transition for all investigated samples. Also, a saturation region is observed in σ (T) curves. It is found that conduction mechanism is governed by hopping process. The conductivity of the material decreases with increasing sodium deficiency. The transition temperature and the activation energy values inferred from grain boundary resistance and conductivity analysis are closed to each other. Such result confirms the contribution of grain boundary on the electrical conductivity. The variation of the Average Normalized Change (ANC) and its derivative with temperature gives important information about the available density of trapped charge states. The obtained results explain the observed saturation region in conductivity at high temperature region.

Fragile surface zero-energy flat bands in three-dimensional chiral superconductors

NASA Astrophysics Data System (ADS)

Kobayashi, Shingo; Tanaka, Yukio; Sato, Masatoshi

2015-12-01

We study surface zero-energy flat bands in three-dimensional chiral superconductors with pz(px+i py) ν -wave pairing symmetry (ν is a nonzero integer), based on topological arguments and tunneling conductance. It is shown that the surface flat bands are fragile against (i) the surface misorientation and (ii) the surface Rashba spin-orbit interaction. The fragility of (i) is specific to chiral SCs, whereas that of (ii) happens for general odd-parity SCs. We demonstrate that these flat-band instabilities vanish or suppress a zero-bias conductance peak in a normal/insulator/superconductor junction, which behavior is clearly different from high-Tc cuprates and noncentrosymmetric superconductors. By calculating the angle-resolved conductance, we also discuss a topological surface state associated with the coexistence of line and point nodes.

Anisotropic magnetoresistance and tunneling magnetoresistance of conducting filaments in NiO with different resistance states

NASA Astrophysics Data System (ADS)

Zhao, Diyang; Qiao, Shuang; Luo, Yuxiang; Chen, Aitian; Zhang, Pengfei; Zheng, Ping; Sun, Zhong; Guo, Minghua; Chiang, F.-K.; Wu, Jian; Luo, Jianlin; Li, Jianqi; Wang, Yayu; Zhao, Yonggang; Tsinghua University Team; Chinese Academy of Sciences Collaboration

Resistive switching (RS) effect in conductor/insulator/conductor thin-film stacks has attracted much attention due to its interesting physics and potentials for applications. NiO is one of the most representative systems and its RS effect has been generally explained by the formation and rupture of Ni related conducting filaments, which are very unique since they are formed by electric forming process. We study the MR behaviors in NiO RS films with different resistance states. Rich and interesting MR behaviors were observed, including the normal and anomalous anisotropic magnetoresistance (AMR) and tunneling magnetoresistance (TMR), etc., which provide new insights into the nature of the filaments and their evolution in the resistive switching process. First-principles calculation reveals the essential role of oxygen migration into the filaments during the RESET process and can account for the experimental results. Our work provides a new avenue for the exploration of the conducting filaments in RS materials, and is significant for understanding the RS mechanism as well as multifunctional device design.

Substitution of Ni for Fe in superconducting Fe 0.98 Te 0.5 Se 0.5 depresses the normal-state conductivity but not the magnetic spectral weight

DOE PAGES

Wang, Jinghui; Zhong, Ruidan; Li, Shichao; ...

2015-01-05

We have performed systematic resistivity and inelastic neutron scattering measurements on Fe₀.₉₈₋ zNi zTe₀.₅Se₀.₅ samples to study the impact of Ni substitution on the transport properties and the low-energy (≤ 12 meV) magnetic excitations. It is found that, with increasing Ni doping, both the conductivity and superconductivity are gradually suppressed; in contrast, the low-energy magnetic spectral weight changes little. Comparing with the impact of Co and Cu substitution, we find that the effects on conductivity and superconductivity for the same degree of substitution grow systematically as the atomic number of the substituent deviates from that of Fe. The impact ofmore » the substituents as scattering centers appears to be greater than any contribution to carrier concentration. The fact that low-energy magnetic spectral weight is not reduced by increased electron scattering indicates that the existence of antiferromagnetic correlations does not depend on electronic states close to the Fermi energy.« less

Experiences and Perspectives About Breastfeeding in "Public": A Qualitative Exploration Among Normal-Weight and Obese Mothers.

PubMed

McKenzie, Shanice A; Rasmussen, Kathleen M; Garner, Christine D

2018-01-01

Women face societal and cultural barriers to breastfeeding. These challenges have been investigated in international studies and U.S. public opinion polls; however, mothers' experiences with breastfeeding in public in the United States remain unexplored. Research aim: The aim of this study was to describe the experiences of obese and normal-weight women with breastfeeding in public in central New York. Pregnant women ( N = 26) in central New York who intended to breastfeed and were either normal weight or obese were enrolled during their third trimester. A longitudinal, qualitative study was conducted to obtain information about women's experiences from birth through 3 to 6 months postpartum. Interviews were audio recorded, transcribed, and verified for accuracy. Transcripts were analyzed iteratively using conventional content analysis. The concept of "public" was situational rather than a set of physical places; women experienced challenges while breastfeeding around others in private locations that were indistinguishable from those they encountered in places typically considered public. Women experienced social and physical awkwardness including perceived lack of acceptability, fear of confrontation, exposure, and positioning difficulties. They used strategies to reduce awkwardness, for example, being "discreet" and minimizing breastfeeding around other people. Obese women experienced similar challenges but to a greater degree than normal-weight women. "Breastfeeding around others" described mother's experiences more accurately than "breastfeeding in public" and was experienced as awkward both socially and physically, particularly by obese women. Strategies are needed to normalize breastfeeding in the United States and to prepare mothers for the challenges of breastfeeding around others.

The Initiation of Smooth Pursuit is Delayed in Anisometropic Amblyopia

PubMed Central

Raashid, Rana Arham; Liu, Ivy Ziqian; Blakeman, Alan; Goltz, Herbert C.; Wong, Agnes M. F.

2016-01-01

Purpose Several behavioral studies have shown that the reaction times of visually guided movements are slower in people with amblyopia, particularly during amblyopic eye viewing. Here, we tested the hypothesis that the initiation of smooth pursuit eye movements, which are responsible for accurately keeping moving objects on the fovea, is delayed in people with anisometropic amblyopia. Methods Eleven participants with anisometropic amblyopia and 14 visually normal observers were asked to track a step-ramp target moving at ±15°/s horizontally as quickly and as accurately as possible. The experiment was conducted under three viewing conditions: amblyopic/nondominant eye, binocular, and fellow/dominant eye viewing. Outcome measures were smooth pursuit latency, open-loop gain, steady state gain, and catch-up saccade frequency. Results Participants with anisometropic amblyopia initiated smooth pursuit significantly slower during amblyopic eye viewing (206 ± 20 ms) than visually normal observers viewing with their nondominant eye (183 ± 17 ms, P = 0.002). However, mean pursuit latency in the anisometropic amblyopia group during binocular and monocular fellow eye viewing was comparable to the visually normal group. Mean open-loop gain, steady state gain, and catch-up saccade frequency were similar between the two groups, but participants with anisometropic amblyopia exhibited more variable steady state gain (P = 0.045). Conclusions This study provides evidence of temporally delayed smooth pursuit initiation in anisometropic amblyopia. After initiation, the smooth pursuit velocity profile in anisometropic amblyopia participants is similar to visually normal controls. This finding differs from what has been observed previously in participants with strabismic amblyopia who exhibit reduced smooth pursuit velocity gains with more catch-up saccades. PMID:27070109

Hole Transport in the Upper Hubbard Band in Ge:Cu under Uniaxial Pressure

NASA Astrophysics Data System (ADS)

Walukiewicz, W.; Dubon, O. D.; Silvestri, H. H.; Haller, E. E.

1998-03-01

We have reported recently on a uniaxial stress induced transformation of the ground state of Cu triple acceptors in Ge from highly localized 1s^3 to the much more extended 1s^22s^1 configuration (O.D. Dubon et. al., Phys Rev Lett. 78, 3519, (1997)). We find that the transformation leads to a gigantic enhancement of the low temperature conductivity. The conductivity is due to hole transport in the upper Hubbard band formed by overcharged 1s^22s^2 states. We have calculated hole mobilities in this band assuming that the states in the upper Hubbard band can be treated in the optical approximation as normal extended states with a well-defined effective mass. We find that for Cu concentrations below 10^15 cm-3 the experimentally observed mobilities approach 10^6 cm^2/Vs. These very high mobilities can be explained by hole scattering from ionized and neutral impurity centers. At higher Cu concentrations we observe an onset of Anderson localization that manifests itself in a thermally activated low temperature mobility. This work was supported by US DOE under Contract No. DE-AC03-76SF00098.

Nanoscale Electronic Structure of Cuprate Superconductors Investigated with Scanning Tunneling Spectroscopy

NASA Astrophysics Data System (ADS)

Williams, Tess Lawanna

Despite 25 years of intense research activity, high-temperature superconductors remain poorly understood, with the underlying pairing mechanism still unidentified. Efforts are complicated by the remarkably complex phase diagram, rich in energy-dependent charge and spin orders. In this thesis I describe the use of a Scanning Tunneling Microscope (STM) to study energy-dependent charge orders in Bi2-- yPbySr2CuO6+delta , a cuprate high-temperature superconductor. STM, a surface-sensitive probe used to map electronic structure with sub-meV energy resolution and sub-A spatial resolution, has contributed greatly to our current understanding of the cuprate high-temperature superconductors. However, STM data is acquired with a constant-current normalization condition. The measured differential conductance, g(x, y, V), is often taken to be proportional to the density of states at energy eV (where V is the voltage applied between tip and sample). In fact, due to the normalization condition, the measured g(x, y, V) is actually the quotient of the density of states at energy eV and the integrated density of states from the Fermi energy to eV. This unavoidable quotient may fold electronic structure from its true energy range into other energies. I discuss a new method to correct STM differential conductance spectra to remove the constant-current normalization condition. Using local work function measurements and the constant-current topograph, I create a map which does not suffer from the setpoint effect and contains a mixture of topographic information and properly normalized spectroscopic information. I apply this method to the extraction of the incommensurate charge modulation at q⃗˜34 2pa0 . I also extend the study of electronic nematic order, an atomic-lattice-periodic C4 → C2 symmetry breaking, from highly underdoped Bi2 Sr2CaCu2O 8+delta [28] to overdoped Bi2--yPb ySr2CuO6+/-delta. I find that the electronic nematic order parameter is robust to change of scan angle. I define and contrast three different electronic nematic orders with different phases with respect to the crystal. I discuss the effect of the choice of normalization and possible alternate explanations for the source of the calculated nematic order. Finally, I discuss a drift-correction technique, which removes picometer scale drift that is introduced into a spectral map by experimental imperfections, and characterize the optimal algorithm and potential artifacts that drift-correction may introduce.

JPRS Report, Science & Technology, USSR: Engineering & Equipment.

DTIC Science & Technology

1988-11-04

correspondent: "We will conduct an experiment with a welded joint of a pipe in your presence. First we will photograph it in the normal state and then...following heating and an impact, or under pressure in which the product changes shape by fractions of a micron and vibrates. The two images lie in a single...light spot. It consists of feeder optics including a photocathode, a pair of microchannel plates in a herringbone configuration, and four other elec

The Effect of Increased Intracranial Pressure on Vestibular Evoked Myogenic Potentials in Superior Canal Dehiscence Syndrome

PubMed Central

Janky, Kristen L.; Zuniga, M. Geraldine; Schubert, Michael C; Carey, John P

2014-01-01

Objective To determine if vestibular evoked myogenic potential (VEMP) responses change during inversion in patients with superior canal dehiscence syndrome (SCDS) compared to controls. Methods Sixteen subjects with SCDS (mean: 43, range 30–57 years) and 15 age-matched, healthy subjects (mean: 41, range 22–57 years) completed cervical VEMP (cVEMP) in response to air conduction click stimuli and ocular VEMP (oVEMP) in response to air conduction 500 Hz tone burst stimuli and midline tap stimulation. All VEMP testing was completed in semi-recumbent and inverted conditions. Results SCDS ears demonstrated significantly larger oVEMP peak-to-peak amplitudes in comparison to normal ears in semi-recumbency. While corrected cVEMP peak-to-peak amplitudes were larger in SCDS ears; this did not reach significance in our sample. Overall, there was not a differential change in o- or cVEMP amplitude with inversion between SCDS and normal subjects. Conclusions Postural-induced changes in o- and cVEMP responses were measured in the steady state regardless of whether the labyrinth was intact or dehiscent. Significance VEMP responses are blunted during inversion. Although steady-state measurements of VEMPs during inversion do not increase diagnostic accuracy for SCDS, the findings suggest that inversion may provide more general insights into the equilibration of pressures between intracranial and intralabyrinthine fluids. PMID:25103787

Density Functional Theory Calculations Revealing Metal-like Band Structures for Ultrathin Ge {111} and {211} Surface Layers.

PubMed

Tan, Chih-Shan; Huang, Michael Hsuan-Yi

2018-05-21

To find out if germanium should also possess facet-dependent electrical conductivity properties, surface state density functional theory (DFT) calculations were performed on 1-6 layers of Ge (100), (110), (111), and (211) planes. Tunable Ge (100) and (110) planes always present the same semiconducting band structure with a band gap of 0.67 eV expected of bulk germanium. In contrast, 1, 2, 4, and 5 layers of Ge (111) and (211) plane models show metal-like band structures with continuous density of states (DOS) throughout the entire band. For 3 and 6 layers of Ge (111) and (211) plane models, the normal semiconducting band structure was obtained. The plane layers with metal-like band structures also show Ge-Ge bond length deviations and bond distortions, as well as significantly different 4s and 4p frontier orbital electron count and their relative percentages integrated over the valence and conduction bands from those of the semiconducting state. These differences should contribute to strikingly dissimilar band structures. The calculation results suggest observation of facet-dependent electrical conductivity properties of germanium materials, and transistors made of germanium may also need to consider the facet effects with shrinking dimensions approaching 3 nm. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Monolithic quasi-solid-state dye-sensitized solar cells based on graphene modified mesoscopic carbon counter electrodes

NASA Astrophysics Data System (ADS)

Rong, Yaoguang; Li, Xiong; Liu, Guanghui; Wang, Heng; Ku, Zhiliang; Xu, Mi; Liu, Linfeng; Hu, Min; Yang, Ying; Han, Hongwei

2013-03-01

We have developed a monolithic quasi-solid-state dye-sensitized solar cell (DSSC) based on graphene modified mesoscopic carbon counter electrode (GC-CE), which offers a promising prospect for commercial applications. Based on the design of a triple layer structure, the TiO2 working electrode layer, ZrO2 spacer layer and carbon counter electrode (CE) layer are constructed on a single conducting glass substrate by screen-printing. The quasi-solid-state polymer gel electrolyte employs a polymer composite as the gelator and could effectively infiltrate into the porous layers. Fabricated with normal carbon counter electrode (NC-CE) containing graphite and carbon black, the device shows a power conversion efficiency (PCE) of 5.09% with the fill factor (FF) of 0.63 at 100 mW cm-2 AM1.5 illumination. When the NC-CE is modified with graphene sheets, the PCE and FF could be enhanced to 6.27% and 0.71, respectively. This improvement indicates excellent conductivity and high electrocatalytic activity of the graphene sheets, which have been considered as a promising platinum-free electrode material for DSSCs.

Progress toward steady-state tokamak operation exploiting the high bootstrap current fraction regime

DOE PAGES

Ren, Q. L.; Garofalo, A. M.; Gong, X. Z.; ...

2016-06-20

Recent DIII-D experiments have increased the normalized fusion performance of the high bootstrap current fraction tokamak regime toward reactor-relevant steady state operation. The experiments, conducted by a joint team of researchers from the DIII-D and EAST tokamaks, developed a fully noninductive scenario that could be extended on EAST to a demonstration of long pulse steady-state tokamak operation. Improved understanding of scenario stability has led to the achievement of very high values of β p and β N despite strong ITBs. Good confinement has been achieved with reduced toroidal rotation. These high β p plasmas challenge the energy transport understanding, especiallymore » in the electron energy channel. A new turbulent transport model, named 2 TGLF-SAT1, has been developed which improves the transport prediction. Experiments extending results to long pulse on EAST, based on the physics basis developed at DIII-D, have been conducted. Finally, more investigations will be carried out on EAST with more additional auxiliary power to come online in the near term.« less

Magneto thermal conductivity of superconducting Nb with intermediate level of impurity

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

L.S. Sharath Chandra, M.K. Chattopadhyay, S.B. Roy, V.C. Sahni, G.R. Myneni

2012-03-01

Niobium materials with intermediate purity level are used for fabrication of superconducting radio frequency cavities (SCRF), and thermal conductivity is an important parameter influencing the performance of such SCRF cavities. We report here the temperature and magnetic field dependence of thermal conductivity {kappa} for superconducting niobium (Nb) samples, for which the electron mean free path I{sub e}, the phonon mean free path I{sub g}, and the vortex core diameter 2r{sub C} are of the same order of magnitude. The measured thermal conductivity is analyzed using the effective gap model (developed for I{sub e} >> 2r{sub C} (Dubeck et al 1963more » Phys. Rev. Lett. 10 98)) and the normal core model (developed for I{sub e} << 2r{sub C} (Ward and Dew-Hughes 1970 J. Phys. C: Solid St. Phys. 3 2245)). However, it is found that the effective gap model is not suitable for low temperatures when I{sub e} {approx} 2r{sub C}. The normal core model, on the other hand, is able to describe {kappa}(T,H) over the entire temperature range except in the field regime between H{sub C1} and H{sub C2} i.e. in the mixed state. It is shown that to understand the complete behavior of {kappa} in the mixed state, the scattering of quasi-particles from the vortex cores and the intervortex quasi-particle tunneling are to be invoked. The quasi-particle scattering from vortices for the present system is understood in terms of the framework of Sergeenkov and Ausloos (1995 Phys. Rev. B 52 3614) extending their approach to the case of Nb. The intervortex tunneling is understood within the framework of Schmidbauer et al (1970 Z. Phys. 240 30). Analysis of the field dependence of thermal conductivity shows that while the quasi-particle scattering from vortices dominates in the low fields, the intervortex quasi-particle tunneling dominates in high fields. Analysis of the temperature dependence of thermal conductivity shows that while the quasi-particle scattering is dominant at low temperatures, the intervortex quasi-particle tunneling is dominant at high temperatures.« less

Using Local Perturbations To Manipulate and Control Pointer States in Quantum Dot Systems

NASA Astrophysics Data System (ADS)

Akis, Richard; Speyer, Gil; Ferry, David; Brunner, Roland

2012-02-01

Recently, scanning gate microscopy (SGM) was used to image scarred wave functions in an open InAs quantum dot[1]. The SGM tip provides a local potential perturbation and imaging is performed by measuring changes in conductance. Scarred wave functions, long associated with quantum chaos, have been shown in open dots to correspond to pointer states[2], eigenstates that survive the decoherence process that occurs via coupling to the environment. Pointer states modulate the conductance, yielding periodic fluctuations and the scars, normally thought unstable, are stabilized by quantum Darwinism [3]. We shall show that, beyond probing, pointer states can be manipulated by local perturbations. Particularly interesting effects occur in coupled quantum dot arrays, where a pointer state localized in one dot can be shifted over into another with a perturbation in a completely different part of the system. These nonlocal effects may perhaps be exploited to give such systems an exotic functionality. [1] A. M. Burke, R. Akis, T. E. Day, Gil Speyer, D. K. Ferry, and B. R. Bennett, Phys. Rev. Lett. 104, 176801 (2010). [2] D. K. Ferry, R. Akis, and J. P. Bird, Phys. Rev. Lett. 104, 176801 (2004). [3] R. Brunner, R. Akis,D. K. Ferry, F. Kuchar,and R. Meisels, Phys. Rev. Lett. 101, 024102 (2008).

Determination of stress intensity factors for interface cracks under mixed-mode loading

NASA Technical Reports Server (NTRS)

Naik, Rajiv A.; Crews, John H., Jr.

1992-01-01

A simple technique was developed using conventional finite element analysis to determine stress intensity factors, K1 and K2, for interface cracks under mixed-mode loading. This technique involves the calculation of crack tip stresses using non-singular finite elements. These stresses are then combined and used in a linear regression procedure to calculate K1 and K2. The technique was demonstrated by calculating three different bimaterial combinations. For the normal loading case, the K's were within 2.6 percent of an exact solution. The normalized K's under shear loading were shown to be related to the normalized K's under normal loading. Based on these relations, a simple equation was derived for calculating K1 and K2 for mixed-mode loading from knowledge of the K's under normal loading. The equation was verified by computing the K's for a mixed-mode case with equal and normal shear loading. The correlation between exact and finite element solutions is within 3.7 percent. This study provides a simple procedure to compute K2/K1 ratio which has been used to characterize the stress state at the crack tip for various combinations of materials and loadings. Tests conducted over a range of K2/K1 ratios could be used to fully characterize interface fracture toughness.

[Clinical-diagnostic estimation of carbohydrates metabolism in obturation jaundice].

PubMed

Nychytaĭlo, M Iu; Malyk, S V

2004-07-01

Complex examination of 175 patients with obturation jaundice was conducted, peculiar attention was spared to the carbohydrates metabolism changes, characterizing hepatic state. It was established, that in obturation jaundice in the liver there are occurring inflammatory changes and disturbances of all kinds of metabolism, including that of carbohydrates, severity of which depends on duration of jaundice, the concurrent diseases presence, they shows lowering of the glucose and glycogen level in the blood, as well as the hepatic glycogen content, that's why they may be applied as a complex of prognostic criterions for the disease course. An early conduction of operative treatment, elimination of the biliary ducts impassability promote the rehabilitation period shortening and the hepatic functional activity normalization.

Interstitial hydraulic conductivity and interstitial fluid pressure for avascular or poorly vascularized tumors.

PubMed

Liu, L J; Schlesinger, M

2015-09-07

A correct description of the hydraulic conductivity is essential for determining the actual tumor interstitial fluid pressure (TIFP) distribution. Traditionally, it has been assumed that the hydraulic conductivities both in a tumor and normal tissue are constant, and that a tumor has a much larger interstitial hydraulic conductivity than normal tissue. The abrupt transition of the hydraulic conductivity at the tumor surface leads to non-physical results (the hydraulic conductivity and the slope of the TIFP are not continuous at tumor surface). For the sake of simplicity and the need to represent reality, we focus our analysis on avascular or poorly vascularized tumors, which have a necrosis that is mostly in the center and vascularization that is mostly on the periphery. We suggest that there is an intermediary region between the tumor surface and normal tissue. Through this region, the interstitium (including the structure and composition of solid components and interstitial fluid) transitions from tumor to normal tissue. This process also causes the hydraulic conductivity to do the same. We introduce a continuous variation of the hydraulic conductivity, and show that the interstitial hydraulic conductivity in the intermediary region should be monotonically increasing up to the value of hydraulic conductivity in the normal tissue in order for the model to correspond to the actual TIFP distribution. The value of the hydraulic conductivity at the tumor surface should be the lowest in value. Copyright © 2015 Elsevier Ltd. All rights reserved.

A quantitative description of normal AV nodal conduction curve in man.

PubMed

Teague, S; Collins, S; Wu, D; Denes, P; Rosen, K; Arzbaecher, R

1976-01-01

The AV nodal conduction curve generated by the atrial extrastimulus technique has been described only qualitatively in man, making clinical comparison of known normal curves with those of suspected AV nodal dysfunction difficult. Also, the effects of physiological and pharmacological interventions have not been quantifiable. In 50 patients with normal AV conduction as defined by normal AH (less than 130 ms), normal AV nodal effective and functional refractory periods (less than 380 and less than 500 ms), and absence of demonstrable dual AV nodal pathways, we found that conduction curves (at sinus rhythm or longest paced cycle length) can be described by an exponential equation of the form delta = Ae-Bx. In this equation, delta is the increase in AV nodal conduction time of an extrastimulus compared to that of a regular beat and x is extrastimulus interval. The natural logarithm of this equation is linear in the semilogarithmic plane, thus permitting the constants A and B to be easily determined by a least-squares regression analysis with a hand calculator.

Non-ambipolar radio-frequency plasma electron source and systems and methods for generating electron beams

DOEpatents

Hershkowitz, Noah [Madison, WI; Longmier, Benjamin [Madison, WI; Baalrud, Scott [Madison, WI

2009-03-03

An electron generating device extracts electrons, through an electron sheath, from plasma produced using RF fields. The electron sheath is located near a grounded ring at one end of a negatively biased conducting surface, which is normally a cylinder. Extracted electrons pass through the grounded ring in the presence of a steady state axial magnetic field. Sufficiently large magnetic fields and/or RF power into the plasma allow for helicon plasma generation. The ion loss area is sufficiently large compared to the electron loss area to allow for total non-ambipolar extraction of all electrons leaving the plasma. Voids in the negatively-biased conducting surface allow the time-varying magnetic fields provided by the antenna to inductively couple to the plasma within the conducting surface. The conducting surface acts as a Faraday shield, which reduces any time-varying electric fields from entering the conductive surface, i.e. blocks capacitive coupling between the antenna and the plasma.

Non-ambipolar radio-frequency plasma electron source and systems and methods for generating electron beams

NASA Technical Reports Server (NTRS)

Hershkowitz, Noah (Inventor); Longmier, Benjamin (Inventor); Baalrud, Scott (Inventor)

2011-01-01

An electron generating device extracts electrons, through an electron sheath, from plasma produced using RF fields. The electron sheath is located near a grounded ring at one end of a negatively biased conducting surface, which is normally a cylinder. Extracted electrons pass through the grounded ring in the presence of a steady state axial magnetic field. Sufficiently large magnetic fields and/or RF power into the plasma allow for helicon plasma generation. The ion loss area is sufficiently large compared to the electron loss area to allow for total non-ambipolar extraction of all electrons leaving the plasma. Voids in the negatively-biased conducting surface allow the time-varying magnetic fields provided by the antenna to inductively couple to the plasma within the conducting surface. The conducting surface acts as a Faraday shield, which reduces any time-varying electric fields from entering the conductive surface, i.e. blocks capacitive coupling between the antenna and the plasma.

Non-ambipolar radio-frequency plasma electron source and systems and methods for generating electron beams

NASA Technical Reports Server (NTRS)

Hershkowitz, Noah (Inventor); Longmier, Benjamin (Inventor); Baalrud, Scott (Inventor)

2009-01-01

An electron generating device extracts electrons, through an electron sheath, from plasma produced using RF fields. The electron sheath is located near a grounded ring at one end of a negatively biased conducting surface, which is normally a cylinder. Extracted electrons pass through the grounded ring in the presence of a steady state axial magnetic field. Sufficiently large magnetic fields and/or RF power into the plasma allow for helicon plasma generation. The ion loss area is sufficiently large compared to the electron loss area to allow for total non-ambipolar extraction of all electrons leaving the plasma. Voids in the negatively-biased conducting surface allow the time-varying magnetic fields provided by the antenna to inductively couple to the plasma within the conducting surface. The conducting surface acts as a Faraday shield, which reduces any time-varying electric fields from entering the conductive surface, i.e. blocks capacitive coupling between the antenna and the plasma.

Qualitative Difference in the Experience of State-Trait Anxiety in Emotionally Disturbed and Normal Children

ERIC Educational Resources Information Center

Finch, A. J., Jr.; And Others

1976-01-01

Responses of emotionally disturbed and normal children to the State-Trait Anxiety Inventory for Children were factor analyzed separately. Two A-State and two A-Trait factors were found, with A-State factors accounting for significantly more variance. Four A-State and two A-Trait factors were found for the normal group, with no significant…

Freeze Tape Cast Thick Mo Doped Li 4Ti 5O 12 Electrodes for Lithium-Ion Batteries

DOE PAGES

Ghadkolai, Milad Azami; Creager, Stephen; Nanda, Jagjit; ...

2017-08-30

Lithium titanate (Li 4Ti 5O 12) powders with and without molybdenum doping (LTO and MoLTO respectively) were synthesized by a solid-state method and used to fabricate electrodes on Cu foil using a normal tape-cast method and a novel freeze-tape-cast method. Modest molybdenum doping produces a significant electronic conductivity increase (e.g. 1 mS cm -1 for MoLTO vs 10 -7 mS cm -1 for LTO) that is thought to reflect a partial Ti 4+ reduction to Ti 3+ with charge compensation by the Mo 6+ dopant, producing a stable mixed-valent Ti 4+/3+ state. Freeze-tape-cast electrodes were fabricated by a variant ofmore » the normal tape-cast method that includes a rapid freezing step in which the solvent in the Cu-foil-supported slurry is rapidly frozen on a cold finger then subsequently sublimed to create unidirectional columnar macropores in the electrode. The resulting electrodes exhibit high porosity and low tortuosity which enhances electrolyte accessibility throughout the full electrode thickness. Freeze-tape-cast electrodes subjected to galvanostatic charge-discharge testing as cathodes in cells vs. a lithium metal anode exhibit higher specific capacity and lower capacity loss at high discharge rates compared with normal-tape-cast electrodes of the same mass loading, despite the fact that the freeze-tape-cast electrodes are nearly twice as thick as the normal tape cast electrodes.« less

From industrially weavable and knittable highly conductive yarns to large wearable energy storage textiles.

PubMed

Huang, Yan; Hu, Hong; Huang, Yang; Zhu, Minshen; Meng, Wenjun; Liu, Chang; Pei, Zengxia; Hao, Chonglei; Wang, Zuankai; Zhi, Chunyi

2015-05-26

Wearable electronic textiles that store capacitive energy are a next frontier in personalized electronics. However, the lack of industrially weavable and knittable conductive yarns in conjunction with high capacitance, limits the wide-scale application of such textiles. Here pristine soft conductive yarns are continuously produced by a scalable method with the use of twist-bundle-drawing technique, and are mechanically robust enough to be knitted to a cloth by a commercial cloth knitting machine. Subsequently, the reduced-graphene-oxide-modified conductive yarns covered with a hierarchical structure of MnO2 nanosheets and a polypyrrole thin film were used to fabricate weavable, knittable and wearable yarn supercapacitors. The resultant modified yarns exhibit specific capacitances as high as 36.6 mF cm(-1) and 486 mF cm(-2) in aqueous electrolyte (three-electrode cell) or 31 mF cm(-1) and 411 mF cm(-2) in all solid-state two-electrode cell. The symmetric solid-state supercapacitor has high energy densities of 0.0092 mWh cm(-2) and 1.1 mWh cm(-3) (both normalized to the whole device) with a long cycle life. Large energy storage textiles are fabricated by weaving our flexible all-solid-state supercapacitor yarns to a 15 cm × 10 cm cloth on a loom and knitting in a woollen wrist band to form a pattern, enabling dual functionalities of energy storage capability and wearability.

Zero energy states at a normal-metal/cuprate-superconductor interface probed by shot noise

NASA Astrophysics Data System (ADS)

Negri, O.; Zaberchik, M.; Drachuck, G.; Keren, A.; Reznikov, M.

2018-06-01

We report measurements of the current noise generated in the optimally doped, x =0.15 , Au-La2-xSrxCuO4 junctions. For high transmission junctions on a (110) surface, we observed a split zero-bias conductance peak (ZBCP), accompanied by enhanced shot noise. We observed no enhanced noise neither in low-transmission junctions on a (110) surface nor in any junction on a (100) surface. We attribute the enhanced noise to Cooper pair transport through the junctions.

Cold starting of fluorescent lamps - part I: a description of the transient regime

NASA Astrophysics Data System (ADS)

Langer, Reinhard; Garner, Richard; Paul, Irina; Horn, Siegfried; Tidecks, Reinhard

2016-10-01

In this paper we give a proposal for the transient behaviour of a cold-started fluorescent lamp, from the generation of the first conductive channel over the normal and abnormal glow discharge and the glow-to-arc (GTA) transition to the arc discharge in the steady state. Starting from the equilibrium voltage-current characteristics of the lamp and considering recent experimental results a qualitative description of the transient regime is developed, which was so far not available in the literature.

Dynamics of static friction between steel and silicon

PubMed Central

Yang, Zhiping; Zhang, H. P.; Marder, M.

2008-01-01

We conducted experiments in which steel and silicon or quartz are clamped together. Even with the smallest tangential forces we could apply, we always found reproducible sliding motions on the nanometer scale. The velocities we study are thousands of times smaller than in previous investigations. The samples first slide and then lock up even when external forces hold steady. One might call the result “slip-stick” friction. We account for the results with a phenomenological theory that results from considering the rate and state theory of dynamic friction at low velocities. Our measurements lead us to set the instantaneous coefficient of static friction that normally enters rate and state theories to zero. PMID:18768792

Field-induced thermal metal-to-insulator transition in underdoped La(2-x)Sr(x)CuO(4+delta).

PubMed

Hawthorn, D G; Hill, R W; Proust, C; Ronning, F; Sutherland, Mike; Boaknin, Etienne; Lupien, C; Tanatar, M A; Paglione, Johnpierre; Wakimoto, S; Zhang, H; Taillefer, Louis; Kimura, T; Nohara, M; Takagi, H; Hussey, N E

2003-05-16

The transport of heat and charge in cuprates was measured in single crystals of La(2-x)Sr(x)CuO(4+delta) (LSCO) across the doping phase diagram at low temperatures. In underdoped LSCO, the thermal conductivity is found to decrease with increasing magnetic field in the T-->0 limit, in striking contrast to the increase observed in all superconductors, including cuprates at higher doping. In heavily underdoped LSCO, where superconductivity can be entirely suppressed with an applied magnetic field, we show that a novel thermal metal-to-insulator transition takes place upon going from the superconducting state to the field-induced normal state.

Antiferromagnetic d-Electron Exchange via a Spin-Singlet π-Electron Ground State in an Organic Conductor

NASA Astrophysics Data System (ADS)

Tokumoto, T.; Brooks, J. S.; Oshima, Y.; Choi, E. S.; Brunel, L. C.; Akutsu, H.; Kaihatsu, T.; Yamada, J.; van Tol, J.

2008-04-01

Electron spin resonance reveals the spin behavior of conduction (π) and localized (d) electrons in β-(BDA-TTP)2MCl4 (M=Fe, Ga). Both the Ga3+(S=0) and Fe3+(S=5/2) compounds exhibit a metal-insulator transition at 113 K with the simultaneous formation of a spin-singlet ground state in the π electron system of the donor molecules. The behavior is consistent with charge ordering in β-(BDA-TTP)2MCl4 at the metal-insulator transition. At 5 K, the Fe3+ compound orders antiferromagnetically, even though the π electrons, which normally would facilitate magnetic exchange, are localized nonmagnetic singlets.

Josephson supercurrent through a topological insulator surface state.

PubMed

Veldhorst, M; Snelder, M; Hoek, M; Gang, T; Guduru, V K; Wang, X L; Zeitler, U; van der Wiel, W G; Golubov, A A; Hilgenkamp, H; Brinkman, A

2012-02-19

The long-sought yet elusive Majorana fermion is predicted to arise from a combination of a superconductor and a topological insulator. An essential step in the hunt for this emergent particle is the unequivocal observation of supercurrent in a topological phase. Here, direct evidence for Josephson supercurrents in superconductor (Nb)-topological insulator (Bi(2)Te(3))-superconductor electron-beam fabricated junctions is provided by the observation of clear Shapiro steps under microwave irradiation, and a Fraunhofer-type dependence of the critical current on magnetic field. Shubnikov-de Haas oscillations in magnetic fields up to 30 T reveal a topologically non-trivial two-dimensional surface state. This surface state is attributed to mediate the ballistic Josephson current despite the fact that the normal state transport is dominated by diffusive bulk conductivity. The lateral Nb-Bi(2)Te(3)-Nb junctions hence provide prospects for the realization of devices supporting Majorana fermions.

Angular particle impingement studies of thermoplastic materials at normal incidence

NASA Technical Reports Server (NTRS)

Rao, P. V.; Buckley, D. H.

1985-01-01

Scanning electron microscope studies were conducted to characterize the erosion resistance of polymethyl methacrylate (PMMA), polycarbonate (PC), polytetrafluorethylene (PTFE), and ultra-high-molecular-weight polyethylene (UHMWPE). Erosion was caused by a jet of angular microparticles of crushed glass at normal incidence. Material built up above the original surface on all of the materials. As erosion progressed, this buildup disappeared. UHMWPE was the most resistant material and PMMA the least. The most favorable properties for high erosion resistance were high values of ultimate elongation, maximum service temperature, and strain energy and a low value of the modulus of elasticity. Erosion-rate-versus-time curves of PC and PTFE exhibited incubation, acceleration, and steady-state periods. PMMA also exhibited a deceleration period, and an incubation period with deposition was observed for UHMWPE.

Tonic nanomolar dopamine enables an activity-dependent phase recovery mechanism that persistently alters the maximal conductance of the hyperpolarization-activated current in a rhythmically active neuron.

PubMed

Rodgers, Edmund W; Fu, Jing Jing; Krenz, Wulf-Dieter C; Baro, Deborah J

2011-11-09

The phases at which network neurons fire in rhythmic motor outputs are critically important for the proper generation of motor behaviors. The pyloric network in the crustacean stomatogastric ganglion generates a rhythmic motor output wherein neuronal phase relationships are remarkably invariant across individuals and throughout lifetimes. The mechanisms for maintaining these robust phase relationships over the long-term are not well described. Here we show that tonic nanomolar dopamine (DA) acts at type 1 DA receptors (D1Rs) to enable an activity-dependent mechanism that can contribute to phase maintenance in the lateral pyloric (LP) neuron. The LP displays continuous rhythmic bursting. The activity-dependent mechanism was triggered by a prolonged decrease in LP burst duration, and it generated a persistent increase in the maximal conductance (G(max)) of the LP hyperpolarization-activated current (I(h)), but only in the presence of steady-state DA. Interestingly, micromolar DA produces an LP phase advance accompanied by a decrease in LP burst duration that abolishes normal LP network function. During a 1 h application of micromolar DA, LP phase recovered over tens of minutes because, the activity-dependent mechanism enabled by steady-state DA was triggered by the micromolar DA-induced decrease in LP burst duration. Presumably, this mechanism restored normal LP network function. These data suggest steady-state DA may enable homeostatic mechanisms that maintain motor network output during protracted neuromodulation. This DA-enabled, activity-dependent mechanism to preserve phase may be broadly relevant, as diminished dopaminergic tone has recently been shown to reduce I(h) in rhythmically active neurons in the mammalian brain.

Ventral frontal satiation-mediated responses to food aromas in obese and normal-weight women123

PubMed Central

Eiler, William JA; Dzemidzic, Mario; Case, K Rose; Armstrong, Cheryl LH; Mattes, Richard D; Cyders, Melissa A; Considine, Robert V; Kareken, David A

2014-01-01

Background: Sensory properties of foods promote and guide consumption in hunger states, whereas satiation should dampen the sensory activation of ingestive behaviors. Such activation may be disordered in obese individuals. Objective: Using functional magnetic resonance imaging (fMRI), we studied regional brain responses to food odor stimulation in the sated state in obese and normal-weight individuals targeting ventral frontal regions known to be involved in coding for stimulus reward value. Design: Forty-eight women (25 normal weight; 23 obese) participated in a 2-day (fed compared with fasting) fMRI study while smelling odors of 2 foods and an inedible, nonfood object. Analyses were conducted to permit an examination of both general and sensory-specific satiation (satiation effects specific to a given food). Results: Normal-weight subjects showed significant blood oxygen level–dependent responses in the ventromedial prefrontal cortex (vmPFC) to food aromas compared with responses induced by the odor of an inedible object. Normal-weight subjects also showed general (but not sensory-specific) satiation effects in both the vmPFC and orbitofrontal cortex. Obese subjects showed no differential response to the aromas of food and the inedible object when fasting. Within- and between-group differences in satiation were driven largely by changes in the response to the odor of the inedible stimulus. Responses to food aromas in the obese correlated with trait negative urgency, the tendency toward negative affect-provoked impulsivity. Conclusions: Ventral frontal signaling of reward value may be disordered in obesity, with negative urgency heightening responses to food aromas. The observed nature of responses to food and nonfood stimuli suggests that future research should independently quantify each to fully understand brain reward signaling in obesity. This trial was registered at clinicaltrials.gov as NCT02041039. PMID:24695888

Ventral frontal satiation-mediated responses to food aromas in obese and normal-weight women.

PubMed

Eiler, William J A; Dzemidzic, Mario; Case, K Rose; Armstrong, Cheryl L H; Mattes, Richard D; Cyders, Melissa A; Considine, Robert V; Kareken, David A

2014-06-01

Sensory properties of foods promote and guide consumption in hunger states, whereas satiation should dampen the sensory activation of ingestive behaviors. Such activation may be disordered in obese individuals. Using functional magnetic resonance imaging (fMRI), we studied regional brain responses to food odor stimulation in the sated state in obese and normal-weight individuals targeting ventral frontal regions known to be involved in coding for stimulus reward value. Forty-eight women (25 normal weight; 23 obese) participated in a 2-day (fed compared with fasting) fMRI study while smelling odors of 2 foods and an inedible, nonfood object. Analyses were conducted to permit an examination of both general and sensory-specific satiation (satiation effects specific to a given food). Normal-weight subjects showed significant blood oxygen level-dependent responses in the ventromedial prefrontal cortex (vmPFC) to food aromas compared with responses induced by the odor of an inedible object. Normal-weight subjects also showed general (but not sensory-specific) satiation effects in both the vmPFC and orbitofrontal cortex. Obese subjects showed no differential response to the aromas of food and the inedible object when fasting. Within- and between-group differences in satiation were driven largely by changes in the response to the odor of the inedible stimulus. Responses to food aromas in the obese correlated with trait negative urgency, the tendency toward negative affect-provoked impulsivity. Ventral frontal signaling of reward value may be disordered in obesity, with negative urgency heightening responses to food aromas. The observed nature of responses to food and nonfood stimuli suggests that future research should independently quantify each to fully understand brain reward signaling in obesity. © 2014 American Society for Nutrition.

Effect of in-pile degradation of the meat thermal conductivity on the maximum temperature of the plate-type U-Mo dispersion fuels

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

Pavel G. Medvedev

2009-11-01

Effect of in-pile degradation of thermal conductivity on the maximum temperature of the plate-type research reactor fuels has been assessed using the steady-state heat conduction equation and assuming convection cooling. It was found that due to very low meat thickness, characteristic for this type of fuel, the effect of thermal conductivity degradation on the maximum fuel temperature is minor. For example, the fuel plate featuring 0.635 mm thick meat operating at heat flux of 600 W/cm2 would experience only a 20oC temperature rise if the meat thermal conductivity degrades from 0.8 W/cm-s to 0.3 W/cm-s. While degradation of meat thermalmore » conductivity in dispersion-type U-Mo fuel can be very substantial due to formation of interaction layer between the particles and the matrix, and development of fission gas filled porosity, this simple analysis demonstrates that this phenomenon is unlikely to significantly affect the temperature-based safety margin of the fuel during normal operation.« less

The role of conductivity discontinuities in design of cardiac defibrillation

NASA Astrophysics Data System (ADS)

Lim, Hyunkyung; Cun, Wenjing; Wang, Yue; Gray, Richard A.; Glimm, James

2018-01-01

Fibrillation is an erratic electrical state of the heart, of rapid twitching rather than organized contractions. Ventricular fibrillation is fatal if not treated promptly. The standard treatment, defibrillation, is a strong electrical shock to reinitialize the electrical dynamics and allow a normal heart beat. Both the normal and the fibrillatory electrical dynamics of the heart are organized into moving wave fronts of changing electrical signals, especially in the transmembrane voltage, which is the potential difference between the cardiac cellular interior and the intracellular region of the heart. In a normal heart beat, the wave front motion is from bottom to top and is accompanied by the release of Ca ions to induce contractions and pump the blood. In a fibrillatory state, these wave fronts are organized into rotating scroll waves, with a centerline known as a filament. Treatment requires altering the electrical state of the heart through an externally applied electrical shock, in a manner that precludes the existence of the filaments and scroll waves. Detailed mechanisms for the success of this treatment are partially understood, and involve local shock-induced changes in the transmembrane potential, known as virtual electrode alterations. These transmembrane alterations are located at boundaries of the cardiac tissue, including blood vessels and the heart chamber wall, where discontinuities in electrical conductivity occur. The primary focus of this paper is the defibrillation shock and the subsequent electrical phenomena it induces. Six partially overlapping causal factors for defibrillation success are identified from the literature. We present evidence in favor of five of these and against one of them. A major conclusion is that a dynamically growing wave front starting at the heart surface appears to play a primary role during defibrillation by critically reducing the volume available to sustain the dynamic motion of scroll waves; in contrast, virtual electrodes occurring at the boundaries of small, isolated blood vessels only cause minor effects. As a consequence, we suggest that the size of the heart (specifically, the surface to volume ratio) is an important defibrillation variable.

Delayed in vitro development of Up states but normal network plasticity in Fragile X circuits.

PubMed

Motanis, Helen; Buonomano, Dean

2015-09-01

A broad range of neurophysiological phenotypes have been reported since the generation of the first mouse model of Fragile X syndrome (FXS). However, it remains unclear which phenotypes are causally related to the cognitive deficits associated with FXS. Indeed, because many of these phenotypes are known to be modulated by experience, a confounding factor in the interpretation of many studies is whether some phenotypes are an indirect consequence of abnormal development and experience. To help diminish this confound we first conducted an in vitro developmental study of spontaneous neural dynamics in cortical organotypic cultures. A significant developmental increase in network activity and Up states was observed in both wild-type and Fmr1(-/y) circuits, along with a specific developmental delay in the emergence of Up states in knockout circuits. To determine whether Up state regulation is generally impaired in FXS circuits, we examined Up state plasticity using chronic optogenetic stimulation. Wild-type and Fmr1(-/y) stimulated circuits exhibited a significant decrease in overall spontaneous activity including Up state frequency; however, no significant effect of genotype was observed. These results demonstrate that developmental delays characteristic of FXS are recapitulated during in vitro development, and that Up state abnormalities are probably a direct consequence of the disease, and not an indirect consequence of abnormal experience. However, the fact that Fmr1(-/y) circuits exhibited normal homeostatic modulation of Up states suggests that these plasticity mechanisms are largely intact, and that some of the previously reported plasticity deficits could reflect abnormal experience or the engagement of compensatory mechanisms. © 2015 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Spherical microglass particle impingement studies of thermoplastic materials at normal incidence

NASA Technical Reports Server (NTRS)

Veerabhadra Rao, P.; Buckley, D. H.

1984-01-01

Light optical and scanning electron microscope studies were conducted to characterize the erosion resistance of polymethyl methacrylate (PMMA), polycarbonate (PC), polytetrafluoroethylene (PTFE) and ultra-high-molecular-weight-polyethylene (UHMWPE). Erosion was caused by a jet of spherical micro-glass beads at normal impact. During the initial stages of damage, the surfaces of these materials were studied using a profilometer. Material buildup above the original surface was observed on PC and PMMA. As erosion progressed, this buildup disappeared as the pit became deeper. Little or no buildup was observed on PTFE and on UHMWPE. UHMWPE and PTFE are the most resistant materials and PMMA the least. Favorable properties for high erosion resistance seem to be high values of ultimate elongation, and strain energy and a low value of the modulus of elasticity. Erosion-rate-versus-time curves of PC and PTFE exhibit incubation, acceleration and steady state periods. A continuously increasing erosion rate period was observed however for PMMA instead of a steady state period. At early stages of damage and at low impact pressure material removal mechanisms appear to be similar to those for metallic materials.

Spherical micro-glass particle impingement studies of thermoplastic materials at normal incidence

NASA Technical Reports Server (NTRS)

Rao, P. V.; Buckley, D. H.

1983-01-01

Light optical and scanning electron microscope studies were conducted to characterize the erosion resistance of polymethyl methacrylate (PMMA), polycarbonate (PC), polytetrafluoroethylene (PTFE) and ultra-high-molecular-weight-polyethylene (UHMWPE). Erosion was caused by a jet of spherical micro-glass beads at normal impact. During the initial stages of damage, the surfaces of these materials were studied using a profilometer. Material buildup above the original surface was observed on PC and PMMA. As erosion progressed, this buildup disappeared as the pit became deeper. Little or no buildup was observed on PTFE and on UHMWPE. UHMWPE and PTFE are the most resistant materials and PMMA the least. Favorable properties for high erosion resistance seem to be high values of ultimate elongation, and strain energy and a low value of the modulus of elasticity. Erosion-rate-versus-time curves of PC and PTFE exhibit incubation, acceleration and steady state periods. A continuously increasing erosion rate period was observed however for PMMA instead of a steady state period. At early stages of damage and at low impact pressure material removal mechanisms appear to be similar to those for metallic materials.

Direct Shear Tests of Sandstone Under Constant Normal Tensile Stress Condition Using a Simple Auxiliary Device

NASA Astrophysics Data System (ADS)

Cen, Duofeng; Huang, Da

2017-06-01

Tension-shear failure is a typical failure mode in the rock masses in unloading zones induced by excavation or river incision, etc., such as in excavation-disturbed zone of deep underground caverns and superficial rocks of high steep slopes. However, almost all the current shear failure criteria for rock are usually derived on the basis of compression-shear failure. This paper proposes a simple device for use with a servo-controlled compression-shear testing machine to conduct the tension-shear tests of cuboid rock specimens, to test the direct shear behavior of sandstone under different constant normal tensile stress conditions ( σ = -1, -1.5, -2, -2.5 and -3 MPa) as well as the uniaxial tension behavior. Generally, the fracture surface roughness decreases and the proportion of comminution areas in fracture surface increases as the change of stress state from tension to tension-shear and to compression-shear. Stepped fracture is a primary fracture pattern in the tension-shear tests. The shear stiffness, shear deformation and normal deformation (except the normal deformation for σ = -1 MPa) decrease during shearing, while the total normal deformation containing the pre-shearing portion increases as the normal tensile stress level (| σ|) goes up. Shear strength is more sensitive to the normal tensile stress than to the normal compressive stress, and the power function failure criterion (or Mohr envelope form of Hoek-Brown criterion) is examined to be the optimal criterion for the tested sandstone in the full region of tested normal stress in this study.

The microtube-strip heat exchanger - Space power applications for ultra-high conductance gas-gas exchangers

NASA Astrophysics Data System (ADS)

Doty, F. D.; Hosford, Gregory S.; Spitzmesser, Jonathan B.

New developments in manufacturing automation permit the use of large, parallel arrays of very small diameter tubing for greatly increased performance in both spacecraft radiators and recuperators. Micro-tube strip (MTS) recuperators with normalized specific conductance above 1000 W/kgK (20 times the current state of the art) and pressure drops below 1 percent are shown to be realistic long-term goals. The same technology also promises an order of magnitude improvement in radiator specific mass. Some significant space power applications, including the Closed Brayton Cycle and Reverse Brayton Cycle, are discussed. A detailed analysis of the MTS recuperator is presented along with experimental results from prototypes, and some manufacturing considerations are mentioned.

Magnetoresistance Behavior of Conducting Filaments in Resistive-Switching NiO with Different Resistance States.

PubMed

Zhao, Diyang; Qiao, Shuang; Luo, Yuxiang; Chen, Aitian; Zhang, Pengfei; Zheng, Ping; Sun, Zhong; Guo, Minghua; Chiang, Fu-Kuo; Wu, Jian; Luo, Jianlin; Li, Jianqi; Kokado, Satoshi; Wang, Yayu; Zhao, Yonggang

2017-03-29

The resistive switching (RS) effect in various materials has attracted much attention due to its interesting physics and potential for applications. NiO is an important system and its RS effect has been generally explained by the formation/rupture of Ni-related conducting filaments. These filaments are unique since they are formed by an electroforming process, so it is interesting to explore their magnetoresistance (MR) behavior, which can also shed light on unsolved issues such as the nature of the filaments and their evolution in the RS process, and this behavior is also important for multifunctional devices. Here, we focus on MR behavior in NiO RS films with different resistance states. Rich and interesting MR behaviors have been observed, including the normal and anomalous anisotropic magnetoresistance and tunneling magnetoresistance, which provide new insights into the nature of the filaments and their evolution in the RS process. First-principles calculation reveals the essential role of oxygen migration into the filaments during the RESET process and can account for the experimental results. Our work provides a new avenue for exploration of the conducting filaments in resistive switching materials and is significant for understanding the mechanism of RS effect and multifunctional devices.

Dimensional Crossover and Its Interplay with In-Plane Anisotropy of Upper Critical Field in β-(BDA-TTP)2SbF6

NASA Astrophysics Data System (ADS)

Yasuzuka, Syuma; Koga, Hiroaki; Yamamura, Yasuhisa; Saito, Kazuya; Uji, Shinya; Terashima, Taichi; Akutsu, Hiroki; Yamada, Jun-ichi

2017-08-01

Resistance measurements have been performed to investigate the dimensionality and the in-plane anisotropy of the upper critical field (Hc2) for β-(BDA-TTP)2SbF6 in fields H up to 15 T and at temperatures T from 1.5 to 7.5 K, where BDA-TTP stands for 2,5-bis(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene. The upper critical fields parallel and perpendicular to the conduction layer are determined and dimensional crossover from anisotropic three-dimensional behavior to two-dimensional behavior is found at around 6 K. When the direction of H is varied within the conducting layer at 6.0 K, Hc2 shows twofold symmetry: Hc2 along the minimum Fermi wave vector (maximum Fermi velocity) is larger than that along the maximum Fermi wave vector (minimum Fermi velocity). The normal-state magnetoresistance has twofold symmetry similar to Hc2 and shows a maximum when the magnetic field is nearly parallel to the maximum Fermi wave vector. This tendency is consistent with the Fermi surface anisotropy. At 3.5 K, we found clear fourfold symmetry of Hc2 despite the fact that the normal-state magnetoresistance shows twofold symmetry arising from the Fermi surface anisotropy. The origin of the fourfold symmetry of Hc2 is discussed in terms of the superconducting gap structure in β-(BDA-TTP)2SbF6.

New perspectives concerning feedback influences on cardiorespiratory control during rhythmic exercise and on exercise performance.

PubMed

Dempsey, Jerome A

2012-09-01

The cardioaccelerator and ventilatory responses to rhythmic exercise in the human are commonly viewed as being mediated predominantly via feedforward 'central command' mechanisms, with contributions from locomotor muscle afferents to the sympathetically mediated pressor response. We have assessed the relative contributions of three types of feedback afferents on the cardiorespiratory response to voluntary, rhythmic exercise by inhibiting their normal 'tonic' activity in healthy animals and humans and in chronic heart failure. Transient inhibition of the carotid chemoreceptors during moderate intensity exercise reduced muscle sympathetic nerve activity (MSNA) and increased limb vascular conductance and blood flow; and reducing the normal level of respiratory muscle work during heavier intensity exercise increased limb vascular conductance and blood flow. These cardiorespiratory effects were prevented via ganglionic blockade and were enhanced in chronic heart failure and in hypoxia. Blockade of μ opioid sensitive locomotor muscle afferents, with preservation of central motor output via intrathecal fentanyl: (a) reduced the mean arterial blood pressure (MAP), heart rate and ventilatory responses to all steady state exercise intensities; and (b) during sustained high intensity exercise, reduced O(2) transport, increased central motor output and end-exercise muscle fatigue and reduced endurance performance. We propose that these three afferent reflexes - probably acting in concert with feedforward central command - contribute significantly to preserving O(2) transport to locomotor and to respiratory muscles during exercise. Locomotor muscle afferents also appear to provide feedback concerning the metabolic state of the muscle to influence central motor output, thereby limiting peripheral fatigue development.

Phase-incoherent superconducting pairs in the normal state of Ba(Fe(1-x)Co(x))₂As₂.

PubMed

Sheet, Goutam; Mehta, Manan; Dikin, D A; Lee, S; Bark, C W; Jiang, J; Weiss, J D; Hellstrom, E E; Rzchowski, M S; Eom, C B; Chandrasekhar, V

2010-10-15

The normal state properties of the recently discovered ferropnictide superconductors might hold the key to understanding their exotic superconductivity. Using point-contact spectroscopy we show that Andreev reflection between an epitaxial thin film of Ba(Fe(0.92)Co(0.08))₂As₂ and a silver tip can be seen in the normal state of the film up to temperature T∼1.3T(c), where T(c) is the critical temperature of the superconductor. Andreev reflection far above T(c) can be understood only when superconducting pairs arising from strong fluctuation of the phase of the complex superconducting order parameter exist in the normal state. Our results provide spectroscopic evidence of phase-incoherent superconducting pairs in the normal state of the ferropnictide superconductors.

On experimental damage localization by SP2E: Application of H∞ estimation and oblique projections

NASA Astrophysics Data System (ADS)

Lenzen, Armin; Vollmering, Max

2018-05-01

In this article experimental damage localization based on H∞ estimation and state projection estimation error (SP2E) is studied. Based on an introduced difference process, a state space representation is derived for advantageous numerical solvability. Because real structural excitations are presumed to be unknown, a general input is applied therein, which allows synchronization and normalization. Furthermore, state projections are introduced to enhance damage identification. While first experiments to verify method SP2E have already been conducted and published, further laboratory results are analyzed here. Therefore, SP2E is used to experimentally localize stiffness degradations and mass alterations. Furthermore, the influence of projection techniques is analyzed. In summary, method SP2E is able to localize structural alterations, which has been observed by results of laboratory experiments.

Frictional stability and earthquake triggering during fluid pressure stimulation of an experimental fault

NASA Astrophysics Data System (ADS)

Scuderi, M. M.; Collettini, C.; Marone, C.

2017-11-01

It is widely recognized that the significant increase of M > 3.0 earthquakes in Western Canada and the Central United States is related to underground fluid injection. Following injection, fluid overpressure lubricates the fault and reduces the effective normal stress that holds the fault in place, promoting slip. Although, this basic physical mechanism for earthquake triggering and fault slip is well understood, there are many open questions related to induced seismicity. Models of earthquake nucleation based on rate- and state-friction predict that fluid overpressure should stabilize fault slip rather than trigger earthquakes. To address this controversy, we conducted laboratory creep experiments to monitor fault slip evolution at constant shear stress while the effective normal stress was systematically reduced via increasing fluid pressure. We sheared layers of carbonate-bearing fault gouge in a double direct shear configuration within a true-triaxial pressure vessel. We show that fault slip evolution is controlled by the stress state acting on the fault and that fluid pressurization can trigger dynamic instability even in cases of rate strengthening friction, which should favor aseismic creep. During fluid pressurization, when shear and effective normal stresses reach the failure condition, accelerated creep occurs in association with fault dilation; further pressurization leads to an exponential acceleration with fault compaction and slip localization. Our work indicates that fault weakening induced by fluid pressurization can overcome rate strengthening friction resulting in fast acceleration and earthquake slip. Our work points to modifications of the standard model for earthquake nucleation to account for the effect of fluid overpressure and to accurately predict the seismic risk associated with fluid injection.

Phase coherence and Andreev reflection in topological insulator devices

DOE PAGES

Finck, A. D. K.; Kurter, C.; Hor, Y. S.; ...

2014-11-04

Topological insulators (TIs) have attracted immense interest because they host helical surface states. Protected by time-reversal symmetry, they are robust to nonmagnetic disorder. When superconductivity is induced in these helical states, they are predicted to emulate p-wave pairing symmetry, with Majorana states bound to vortices. Majorana bound states possess non-Abelian exchange statistics that can be probed through interferometry. Here, we take a significant step towards Majorana interferometry by observing pronounced Fabry-Pérot oscillations in a TI sandwiched between a superconducting and a normal lead. For energies below the superconducting gap, we observe a doubling in the frequency of the oscillations, arisingmore » from an additional phase from Andreev reflection. When a magnetic field is applied perpendicular to the TI surface, a number of very sharp and gate-tunable conductance peaks appear at or near zero energy, which has consequences for interpreting spectroscopic probes of Majorana fermions. Our results show that TIs are a promising platform for exploring phase-coherent transport in a solid-state system.« less

High-Resolution Faraday Rotation and Electron-Phonon Coupling in Surface States of the Bulk-Insulating Topological Insulator Cu_{0.02}Bi_{2}Se_{3}.

PubMed

Wu, Liang; Tse, Wang-Kong; Brahlek, M; Morris, C M; Aguilar, R Valdés; Koirala, N; Oh, S; Armitage, N P

2015-11-20

We have utilized time-domain magnetoterahertz spectroscopy to investigate the low-frequency optical response of the topological insulator Cu_{0.02}Bi_{2}Se_{3} and Bi_{2}Se_{3} films. With both field and frequency dependence, such experiments give sufficient information to measure the mobility and carrier density of multiple conduction channels simultaneously. We observe sharp cyclotron resonances (CRs) in both materials. The small amount of Cu incorporated into the Cu_{0.02}Bi_{2}Se_{3} induces a true bulk insulator with only a single type of conduction with a total sheet carrier density of ~4.9×10^{12}/cm^{2} and mobility as high as 4000 cm^{2}/V·s. This is consistent with conduction from two virtually identical topological surface states (TSSs) on the top and bottom of the film with a chemical potential ~145 meV above the Dirac point and in the bulk gap. The CR broadens at high fields, an effect that we attribute to an electron-phonon interaction. This assignment is supported by an extended Drude model analysis of the zero-field Drude conductance. In contrast, in normal Bi_{2}Se_{3} films, two conduction channels were observed, and we developed a self-consistent analysis method to distinguish the dominant TSSs and coexisting trivial bulk or two-dimensional electron gas states. Our high-resolution Faraday rotation spectroscopy on Cu_{0.02}Bi_{2}Se_{3} paves the way for the observation of quantized Faraday rotation under experimentally achievable conditions to push the chemical potential in the lowest Landau level.

Analysis of urban regions using AVHRR thermal infrared data

USGS Publications Warehouse

Wright, Bruce

1993-01-01

Using 1-km AVHRR satellite data, relative temperature difference caused by conductivity and inertia were used to distinguish urban and non urban land covers. AVHRR data that were composited on a biweekly basis and distributed by the EROS Data Center in Sioux Falls, South Dakota, were used for the classification process. These composited images are based on the maximum normalized different vegetation index (NDVI) of each pixel during the 2-week period using channels 1 and 2. The resultant images are nearly cloud-free and reduce the need for extensive reclassification processing. Because of the physiographic differences between the Eastern and Western United States, the initial study was limited to the eastern half of the United States. In the East, the time of maximum difference between the urban surfaces and the vegetated non urban areas is the peak greenness period in late summer. A composite image of the Eastern United States for the 2-weel time period from August 30-Septmeber 16, 1991, was used for the extraction of the urban areas. Two channels of thermal data (channels 3 and 4) normalized for regional temperature differences and a composited NDVI image were classified using conventional image processing techniques. The results compare favorably with other large-scale urban area delineations.

Estimating Systemic Exposure to Levonorgestrel from an Oral Contraceptive

PubMed Central

Basaraba, Cale N; Westhoff, Carolyn L; Pike, Malcolm C; Nandakumar, Renu; Cremers, Serge

2017-01-01

Objective The gold standard for measuring oral contraceptive (OC) pharmacokinetics is the 24-hour steady-state area-under-the-curve (AUC). We conducted this study to assess whether limited sampling at steady state or measurements following use of one or two OCs could provide an adequate proxy in epidemiological studies for the progestin 24-hour steady-state AUC of a particular OC. Study Design We conducted a 13-sample, 24-hour pharmacokinetic study on both day 1 and day 21 of the first cycle of a monophasic OC containing 30 μg ethinyl estradiol and 150 μg levonorgestrel (LNG) in 17 normal-weight healthy white women, and a single-dose 9-sample study of the same OC after a one-month washout. We compared the 13-sample steady-state results with several steady-state and single-dose results calculated using parsimonious sampling schemes. Results The 13-sample steady-state 24-hour LNG AUC was highly correlated with the steady-state 24-hour trough value (r = 0.95; 95% CI [0.85, 0.98]) and with the steady-state 6, 8, 12 and 16-hour values (0.92 ≤ r ≤ 0.95). The trough values after one or two doses were moderately correlated with the steady-state 24-hour AUC value (r = 0.70; 95% CI [0.27, 0.90] and 0.77; 95% CI [0.40, 0.92], respectively). Conclusions Single time-point concentrations at steady-state and after administration of one or two OCs gave highly to moderately correlated estimates of steady-state LNG AUC. Using such measures could facilitate prospective pharmaco-epidemiologic studies of the OC and its side effects. PMID:28041990

Spin-controlled negative magnetoresistance resulting from exchange interactions

NASA Astrophysics Data System (ADS)

Agrinskaya, N. V.; Kozub, V. I.; Mikhailin, N. Yu.; Shamshur, D. V.

2017-04-01

We studied conductivity of AlGaAs-GaAs quantum well structures (where centers of the wells were doped by Be) at temperatures higher than 4 K in magnetic fields up 10 T. Throughout all the temperature region considered the conductivity demonstrated activated behavior. At moderate magnetic fields 0.1 T < H < 1 T, we observed negative isotropic magnetoresistance, which was linear in magnetic field while for magnetic field normal with respect to the plane of the wells the magnetoresistance was positive at H > 2T. To the best of our knowledge, it was the first observation of linear negative magnetoresistance, which would be isotropic with respect to the direction of magnetic field. While the isotropic character of magnetoresistance apparently evidences role of spins, the existing theoretical considerations concerning spin effects in conductance fail to explain our experimental results. We believe that such a behavior can be attributed to spin effects supported by exchange interactions between localized states.

Thermal conductivity of layered organic superconductor β-(BDA-TTP)2SbF6 in a parallel magnetic field: Anomalous effect of coreless vortices

NASA Astrophysics Data System (ADS)

Tanatar, M. A.; Ishiguro, T.; Toita, T.; Yamada, J.

2005-01-01

Thermal conductivity κ of the organic superconductor β-(BDA-TTP)2SbF6 was studied down to 0.3 K in magnetic fields H of varying orientation with respect to the superconducting plane. Anomalous plateau shape of the field dependence, κ vs H , is found for orientation of magnetic fields precisely parallel to the plane, in contrast to usual behavior observed in the perpendicular fields. We show that the lack of magnetic-field effect on the heat conduction results from coreless structure of vortices, causing both negligible scattering of phonons and constant in field electronic conduction up to the fields close to the upper critical field Hc2 . Usual behavior is recovered on approaching Hc2 and on slight field inclination from parallel direction, when normal cores are restored. This behavior points to the lack of bulk quasiparticle excitations induced by magnetic field, consistent with the conventional superconducting state.

Effective masking levels for 500 and 2000 Hz bone conduction auditory steady state responses in infants and adults with normal hearing.

PubMed

Small, Susan A; Smyth, Aisling; Leon, Griselle

2014-01-01

Few studies have investigated effective masking levels (EMLs) needed to isolate the test ear for bone conduction assessments in infants. The objective of this study was to determine EMLs for 500 and 2000 Hz bone conduction auditory steady state responses (ASSRs) to amplitude (AM)/frequency-modulated (FM) stimuli for infants and adults with normal hearing. Maturational factors that contribute to infant-adult differences in EMLs will also be investigated. The present study and previously published 1000 and 4000 Hz EML data will be compared to investigate EML across four frequencies. These findings will provide a starting point for implementing clinical masking for infant bone conduction testing using physiological measures. Participants were 15 infants (7 to 35 weeks) and 15 adults (21 to 56 years) with normal hearing. Bone-conducted single ASSR stimuli (research MASTER) were 100% AM and 25% FM at 85 and 101 Hz for 500 and 2000 Hz carrier frequencies, respectively. They were presented at 25 and 35 dB HL for 500 Hz and at 35 and 45 dB HL for 2000 Hz for both infants and adults (approximately 10 and 20 dB SL at each frequency for infants). Air-conducted narrowband maskers were presented to both ears simultaneously. Real-ear to coupler differences were measured to account for differences in the sound pressure developed in infant and adult ear canals as a result of ear-canal size. Data analyses were conducted for mean EMLs across frequency (500 to 4000 Hz) and between age groups. Masked and unmasked ASSR amplitudes were compared for 500 and 2000 Hz. Both infants and adults required much more masking (25 to 33 dB) to eliminate responses at 500 compared with 2000 Hz. On average, infants required 16 dB more masking at 500 Hz and similar amounts of masking at 2000 Hz compared with adults. When adjusted for ear-canal size and bone conduction sensitivity, the pattern of results did not change. Across all four frequencies, infants showed a systematic decrease in mean EMLs with an increase in frequency; all pair-wise comparisons were significant except 2000 versus 4000 Hz. Adults showed smaller frequency-dependent changes in EML (only significantly greater for 500 versus 2000 Hz and 4000 Hz). When ear-canal size and bone conduction sensitivity were taken into account, only 500 Hz required more masking than other frequencies in infants; there were no significant frequency-dependent trends for adults, although the greater EMLs at 1000 versus 2000 Hz and 4000 Hz approached significance. Unmasked and masked amplitudes tended to be larger for 2000 Hz but not for 500 Hz when comparing infants with adults. EMLs appropriate for infants for bone conduction ASSRs elicited to AM/FM stimuli are considerably higher at 500 compared with 2000 Hz. Infants also need more masking at 500 Hz compared with adults but the same amount of masking at 2000 Hz. Comparisons across four frequencies reveal a systematic decrease in EML with an increase in frequency in infants, which is not apparent in adults. Recommended EMLs for AM/FM bone-conducted ASSR stimuli presented at 35 dB HL for 500, 1000, 2000, and 4000 Hz, respectively, are: (1) infants: 81, 68, 59, and 45 dB SPL, and (2) adults: 66, 63, 59, and 55 dB SPL.

Cancer cell redirection biomarker discovery using a mutual information approach.

PubMed

Roche, Kimberly; Feltus, F Alex; Park, Jang Pyo; Coissieux, Marie-May; Chang, Chenyan; Chan, Vera B S; Bentires-Alj, Mohamed; Booth, Brian W

2017-01-01

Introducing tumor-derived cells into normal mammary stem cell niches at a sufficiently high ratio of normal to tumorous cells causes those tumor cells to undergo a change to normal mammary phenotype and yield normal mammary progeny. This phenomenon has been termed cancer cell redirection. We have developed an in vitro model that mimics in vivo redirection of cancer cells by the normal mammary microenvironment. Using the RNA profiling data from this cellular model, we examined high-level characteristics of the normal, redirected, and tumor transcriptomes and found the global expression profiles clearly distinguish the three expression states. To identify potential redirection biomarkers that cause the redirected state to shift toward the normal expression pattern, we used mutual information relationships between normal, redirected, and tumor cell groups. Mutual information relationship analysis reduced a dataset of over 35,000 gene expression measurements spread over 13,000 curated gene sets to a set of 20 significant molecular signatures totaling 906 unique loci. Several of these molecular signatures are hallmark drivers of the tumor state. Using differential expression as a guide, we further refined the gene set to 120 core redirection biomarker genes. The expression levels of these core biomarkers are sufficient to make the normal and redirected gene expression states indistinguishable from each other but radically different from the tumor state.

Cancer cell redirection biomarker discovery using a mutual information approach

PubMed Central

Roche, Kimberly; Feltus, F. Alex; Park, Jang Pyo; Coissieux, Marie-May; Chang, Chenyan; Chan, Vera B. S.; Bentires-Alj, Mohamed

2017-01-01

Introducing tumor-derived cells into normal mammary stem cell niches at a sufficiently high ratio of normal to tumorous cells causes those tumor cells to undergo a change to normal mammary phenotype and yield normal mammary progeny. This phenomenon has been termed cancer cell redirection. We have developed an in vitro model that mimics in vivo redirection of cancer cells by the normal mammary microenvironment. Using the RNA profiling data from this cellular model, we examined high-level characteristics of the normal, redirected, and tumor transcriptomes and found the global expression profiles clearly distinguish the three expression states. To identify potential redirection biomarkers that cause the redirected state to shift toward the normal expression pattern, we used mutual information relationships between normal, redirected, and tumor cell groups. Mutual information relationship analysis reduced a dataset of over 35,000 gene expression measurements spread over 13,000 curated gene sets to a set of 20 significant molecular signatures totaling 906 unique loci. Several of these molecular signatures are hallmark drivers of the tumor state. Using differential expression as a guide, we further refined the gene set to 120 core redirection biomarker genes. The expression levels of these core biomarkers are sufficient to make the normal and redirected gene expression states indistinguishable from each other but radically different from the tumor state. PMID:28594912

Unsaturated flow in a centrifugal field: Measurement of hydraulic conductivity and testing of Darcy's Law

USGS Publications Warehouse

Nimmo, J.R.; Rubin, J.; Hammermeister, D.P.

1987-01-01

A method has been developed to establish steady state flow of water in an unsaturated soil sample spinning in a centrifuge. Theoretical analysis predicts moisture conditions in the sample that depend strongly on soil type and certain operating parameters. For Oakley sand, measurements of flux, water content, and matric potential during and after centrifugation verify that steady state flow can be achieved. Experiments have confirmed the theoretical prediction of a nearly uniform moisture distribution for this medium and have demonstrated that the flow can be effectively one-dimensional. The method was used for steady state measurements of hydraulic conductivity K for relatively dry soil, giving values as low as 7.6 × 10−11 m/s with data obtained in a few hours. Darcy's law was tested by measuring K for different centrifugal driving forces but with the same water content. For the sand at a bulk density of 1.82 Mg/m3 and 27% saturation, results were consistent with Darcy's law for K equal to 5.22 × 10−10 m/s and forces ranging from 216 to 1650 times normal gravity.

The effect of amino acid infusion on anesthesia-induced hypothermia in muscle atrophy model rats.

PubMed

Kanazawa, Masahiro; Ando, Satoko; Tsuda, Michio; Suzuki, Toshiyasu

2010-01-01

An infusion of amino acids stimulates heat production in skeletal muscle and then attenuates the anesthesia-induced hypothermia. However, in a clinical setting, some patients have atrophic skeletal muscle caused by various factors. The present study was therefore conducted to investigate the effect of amino acids on the anesthesia-induced hypothermia in the state of muscle atrophy. As the muscle atrophy model, Sprague-Dawley rats were subjected to hindlimb immobilization for 2 wk. Normal rats and atrophy model rats were randomly assigned to one of the two treatment groups: saline or amino acids (n=8 for each group). Test solutions were administered intravenously to the rats under sevoflurane anesthesia for 180 min, and the rectal temperature was measured. Plasma samples were collected for measurement of insulin, blood glucose, and free amino acids. The rectal temperature was significantly higher in the normal-amino acid group than in the muscle atrophy-amino acid group from 75 to 180 min. The plasma insulin level was significantly higher in the rats given amino acids than in the rats given saline in both normal and model groups. In the rats given amino acids, plasma total free amino acid concentration was higher in the model group than in the normal group. These results indicate that skeletal muscle plays an important role in changes in body temperature during anesthesia and the effect of amino acids on anesthesia-induced hypothermia decreases in the muscle atrophy state. In addition, intravenous amino acids administration during anesthesia induces an increase in the plasma insulin level.

Thermal transport properties in helium near the superfluid transition. I.4He in the normal phase

NASA Astrophysics Data System (ADS)

Dingus, M.; Zhong, F.; Meyer, H.

1986-11-01

The thermal conductivity κ and the associated relaxation time τ to reach steady-state conditions are reported for the normal phase of several very dilute mixtures of3He in4He ( X<4 × 10-6) at saturated vapor pressure near Tλ. The measurements were made over the reduced temperature range 2.5 × 10-6<ɛ<2×10-1, where ɛ ≡ (T-Tλ)/Tλ, and are representative for pure4He. The spacing between the cell plates was 0.147 cm. The systematic uncertainty in the conductivity data is estimated to increase from ˜2% for ɛ=0.2 to ˜4% for ɛ=3 × 10-6. The random scatter due to finite temperature resolution increases to ˜7% at the smallest ɛ. The data are in agreement within the combined uncertainty with recent ones by Tam and Ahlers (cell F, spacing 0.20 cm) and with previous ones in this laboratory taken with a different plate spacing. The thermal diffusivity coefficient D T = κ / ϱ C p obtained from τ is found to agree within better than 15% with the calculated one using data for κ, the density ϱ, and the specific heat C p . Measurements of the effective boundary resistivity R b in the superfluid phase are described. R b is found to depend on the thermal history of the cell when cycled up to 77 K and above. Also, R b shows the beginning of an anomalous increase for ¦ɛ¦≲10-4. The possible reasons for this anomaly are discussed, and their impact on the analysis of conductivity data in the normal phase is appraised.

Normalization of aberrant resting state functional connectivity in fibromyalgia patients following a three month physical exercise therapy

PubMed Central

Flodin, P.; Martinsen, S.; Mannerkorpi, K.; Löfgren, M.; Bileviciute-Ljungar, I.; Kosek, E.; Fransson, P.

2015-01-01

Physical exercise is one of the most efficient interventions to mitigate chronic pain symptoms in fibromyalgia (FM). However, little is known about the neurophysiological mechanisms mediating these effects. In this study we investigated resting-state connectivity using functional magnetic resonance imaging (fMRI) before and after a 15 week standardized exercise program supervised by physical therapists. Our aim was to gain an understanding of how physical exercise influences previously shown aberrant patterns of intrinsic brain activity in FM. Fourteen FM patients and eleven healthy controls successfully completed the physical exercise treatment. We investigated post- versus pre-treatment changes of brain connectivity, as well as changes in clinical symptoms in the patient group. FM patients reported improvements in symptom severity. Although several brain regions showed a treatment-related change in connectivity, only the connectivity between the right anterior insula and the left primary sensorimotor area was significantly more affected by the physical exercise among the fibromyalgia patients compared to healthy controls. Our results suggest that previously observed aberrant intrinsic brain connectivity patterns in FM are partly normalized by the physical exercise therapy. However, none of the observed normalizations in intrinsic brain connectivity were significantly correlated with symptom changes. Further studies conducted in larger cohorts are warranted to investigate the precise relationship between improvements in fibromyalgia symptoms and changes in intrinsic brain activity. PMID:26413476

Normalization of aberrant resting state functional connectivity in fibromyalgia patients following a three month physical exercise therapy.

PubMed

Flodin, P; Martinsen, S; Mannerkorpi, K; Löfgren, M; Bileviciute-Ljungar, I; Kosek, E; Fransson, P

2015-01-01

Physical exercise is one of the most efficient interventions to mitigate chronic pain symptoms in fibromyalgia (FM). However, little is known about the neurophysiological mechanisms mediating these effects. In this study we investigated resting-state connectivity using functional magnetic resonance imaging (fMRI) before and after a 15 week standardized exercise program supervised by physical therapists. Our aim was to gain an understanding of how physical exercise influences previously shown aberrant patterns of intrinsic brain activity in FM. Fourteen FM patients and eleven healthy controls successfully completed the physical exercise treatment. We investigated post- versus pre-treatment changes of brain connectivity, as well as changes in clinical symptoms in the patient group. FM patients reported improvements in symptom severity. Although several brain regions showed a treatment-related change in connectivity, only the connectivity between the right anterior insula and the left primary sensorimotor area was significantly more affected by the physical exercise among the fibromyalgia patients compared to healthy controls. Our results suggest that previously observed aberrant intrinsic brain connectivity patterns in FM are partly normalized by the physical exercise therapy. However, none of the observed normalizations in intrinsic brain connectivity were significantly correlated with symptom changes. Further studies conducted in larger cohorts are warranted to investigate the precise relationship between improvements in fibromyalgia symptoms and changes in intrinsic brain activity.

Conduct problems and level of social competence in Head Start children: prevalence, pervasiveness, and associated risk factors.

PubMed

Webster-Stratton, C; Hammond, M

1998-06-01

The purpose of the current project was to determine the prevalence of conduct problems, low social competence, and associated risk factors in a sample of 4-year-old low-income children (N = 426) from 64 Head Start classrooms in the Seattle area. Conduct problems and social competence were assessed based on a combination of teacher reports, parent reports, and independent observations of children interacting with peers in the classroom and with parents at home. We examined the relative contribution of a variety of risk factors, including maternal history and socioeconomic background, current levels of stress and social support, mothers' emotional state, and parenting competence in relation to "pervasive" (i.e., at home and school) and "nonpervasive" conduct problems and low social competence. Findings indicated similar risk factors for conduct problems and for low social competence, with an ordered increase in the number of risk factors from normal to "nonpervasive" to "pervasive" groups. Harshness of parenting style (i.e., slapping, hitting, yelling) significantly distinguished between the three groups for low social competence and conduct problems. Positive affect, praise, and physical warmth from mothers were positively related to social competence but unrelated to conduct problems.

The entropic brain: a theory of conscious states informed by neuroimaging research with psychedelic drugs.

PubMed

Carhart-Harris, Robin L; Leech, Robert; Hellyer, Peter J; Shanahan, Murray; Feilding, Amanda; Tagliazucchi, Enzo; Chialvo, Dante R; Nutt, David

2014-01-01

Entropy is a dimensionless quantity that is used for measuring uncertainty about the state of a system but it can also imply physical qualities, where high entropy is synonymous with high disorder. Entropy is applied here in the context of states of consciousness and their associated neurodynamics, with a particular focus on the psychedelic state. The psychedelic state is considered an exemplar of a primitive or primary state of consciousness that preceded the development of modern, adult, human, normal waking consciousness. Based on neuroimaging data with psilocybin, a classic psychedelic drug, it is argued that the defining feature of "primary states" is elevated entropy in certain aspects of brain function, such as the repertoire of functional connectivity motifs that form and fragment across time. Indeed, since there is a greater repertoire of connectivity motifs in the psychedelic state than in normal waking consciousness, this implies that primary states may exhibit "criticality," i.e., the property of being poised at a "critical" point in a transition zone between order and disorder where certain phenomena such as power-law scaling appear. Moreover, if primary states are critical, then this suggests that entropy is suppressed in normal waking consciousness, meaning that the brain operates just below criticality. It is argued that this entropy suppression furnishes normal waking consciousness with a constrained quality and associated metacognitive functions, including reality-testing and self-awareness. It is also proposed that entry into primary states depends on a collapse of the normally highly organized activity within the default-mode network (DMN) and a decoupling between the DMN and the medial temporal lobes (which are normally significantly coupled). These hypotheses can be tested by examining brain activity and associated cognition in other candidate primary states such as rapid eye movement (REM) sleep and early psychosis and comparing these with non-primary states such as normal waking consciousness and the anaesthetized state.

Electronic structure and dynamics of thin Ge/GaAs(110) heterostructures

NASA Astrophysics Data System (ADS)

Haight, R.; Silberman, J. A.

1990-10-01

Using angle-resolved picosecond laser photoemission we have investigated both occupied and transiently excited empty states at the surface of Ge grown epitaxially on GaAs(110). We observe a normally unoccupied, Ge layer derived state whose separation from the valence-band maximum of the system is 700±50 meV at six monolayers Ge coverage. The evolution of the electronic structure is followed as a function of coverage and correlated with low-energy electron diffraction. The time dependence of the transiently occupied Ge signal is compared with that of the clean GaAs(110) surface and shows that electrons are prevented from diffusing into the GaAs bulk by the conduction-band offset of 330±40 meV.

The significance of oxygen during contact lens wear.

PubMed

Papas, Eric B

2014-12-01

In order to establish the relevance of oxygen to contemporary contact lens practice, a review of the literature was conducted. The results indicate that there are a number of processes occurring in the normal healthy eye where oxygen is required and which are potentially affected by the presence of a contact lens. These activities appear to take place at all corneal levels, as well as at the limbus. Evidence from laboratory, clinical and modelling studies indicates that what constitutes normal oxygenation (normoxia) depends on, among other things, the physiological system under consideration, corneal location and the state of eye closure. This diversity is reflected in the wide range of minimum lens oxygen transmissibility (Dk/t) requirements that are present in a literature. Copyright © 2014 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

Applied nursing informatics research - state-of-the-art methodologies using electronic health record data.

PubMed

Park, Jung In; Pruinelli, Lisiane; Westra, Bonnie L; Delaney, Connie W

2014-01-01

With the pervasive implementation of electronic health records (EHR), new opportunities arise for nursing research through use of EHR data. Increasingly, comparative effectiveness research within and across health systems is conducted to identify the impact of nursing for improving health, health care, and lowering costs of care. Use of EHR data for this type of research requires use of national and internationally recognized nursing terminologies to normalize data. Research methods are evolving as large data sets become available through EHRs. Little is known about the types of research and analytic methods for applied to nursing research using EHR data normalized with nursing terminologies. The purpose of this paper is to report on a subset of a systematic review of peer reviewed studies related to applied nursing informatics research involving EHR data using standardized nursing terminologies.

Legislature agrees to fund study of marijuana efficacy.

PubMed

1999-10-01

California could be the first State to conduct a research study on medical uses for marijuana under the "Medical Research Act of 1999". S.B. 847 would authorize a three-year program, administered by the University of California, to study which methods of ingesting marijuana are most effective in treating pain and side effects of treatments for AIDS, cancer, glaucoma and seizures. The sponsor of the bill, Sen. John Vasconcellos, initially wanted $1 million in annual funding, but the program will be funded through the normal appropriations process.

Notice of Changes to the Weekly Natural Gas Storage Report

EIA Publications

2015-01-01

On November 19, 2015, EIA will release the Weekly Natural Gas Storage Report (WNGSR) with new data breakouts for five regions of the Lower 48 states, converting from the current three-region structure. On Monday, November 16, 2015, EIA will re-release the data that will be published on Friday, November 13 (for the week ending Friday, November 6) in the new five-region format. The release will be conducted through the same timed countdown procedures used for normal releases on the same WNGSR web page: http://ir.eia.gov/ngs/ngs.html.

The entropic brain: a theory of conscious states informed by neuroimaging research with psychedelic drugs

PubMed Central

Carhart-Harris, Robin L.; Leech, Robert; Hellyer, Peter J.; Shanahan, Murray; Feilding, Amanda; Tagliazucchi, Enzo; Chialvo, Dante R.; Nutt, David

2014-01-01

Entropy is a dimensionless quantity that is used for measuring uncertainty about the state of a system but it can also imply physical qualities, where high entropy is synonymous with high disorder. Entropy is applied here in the context of states of consciousness and their associated neurodynamics, with a particular focus on the psychedelic state. The psychedelic state is considered an exemplar of a primitive or primary state of consciousness that preceded the development of modern, adult, human, normal waking consciousness. Based on neuroimaging data with psilocybin, a classic psychedelic drug, it is argued that the defining feature of “primary states” is elevated entropy in certain aspects of brain function, such as the repertoire of functional connectivity motifs that form and fragment across time. Indeed, since there is a greater repertoire of connectivity motifs in the psychedelic state than in normal waking consciousness, this implies that primary states may exhibit “criticality,” i.e., the property of being poised at a “critical” point in a transition zone between order and disorder where certain phenomena such as power-law scaling appear. Moreover, if primary states are critical, then this suggests that entropy is suppressed in normal waking consciousness, meaning that the brain operates just below criticality. It is argued that this entropy suppression furnishes normal waking consciousness with a constrained quality and associated metacognitive functions, including reality-testing and self-awareness. It is also proposed that entry into primary states depends on a collapse of the normally highly organized activity within the default-mode network (DMN) and a decoupling between the DMN and the medial temporal lobes (which are normally significantly coupled). These hypotheses can be tested by examining brain activity and associated cognition in other candidate primary states such as rapid eye movement (REM) sleep and early psychosis and comparing these with non-primary states such as normal waking consciousness and the anaesthetized state. PMID:24550805

Is Participatory Action Research an innovative pedagogical alternative for training teachers as researchers? The training plan and evaluation for normal schools.

PubMed

Paredes-Chi, Arely Anahy; Castillo-Burguete, María Teresa

2018-06-01

Normal schools in Mexico train teachers for basic level education. Classified as Higher Education Institutions, part of their mandate is to conduct scientific research to improve educational quality. Currently, normal school students can meet graduation requirements by either writing a thesis or reporting on professional practice using Participatory Action Research (PAR). Teachers at normal schools have only limited experience in conducting and supervising PAR projects. With the aim of analyzing the situation and addressing this paradox, we used PAR to develop a plan to train normal school teachers in application of PAR methodology. We present the training proposal and evaluate its results in a pilot phase. These suggest that PAR represents an innovative option for training teachers to conduct research and therefore fulfill part of their responsibilities at normal schools in Mexico. Changes in institutional culture and structure would be required for successful implementation of PAR in this context. Copyright © 2018 Elsevier Ltd. All rights reserved.

Using Multi-scale Dynamic Rupture Models to Improve Ground Motion Estimates: ALCF-2 Early Science Program Technical Report

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

Ely, Geoffrey P.

2013-10-31

This project uses dynamic rupture simulations to investigate high-frequency seismic energy generation. The relevant phenomena (frictional breakdown, shear heating, effective normal-stress fluctuations, material damage, etc.) controlling rupture are strongly interacting and span many orders of magnitude in spatial scale, requiring highresolution simulations that couple disparate physical processes (e.g., elastodynamics, thermal weakening, pore-fluid transport, and heat conduction). Compounding the computational challenge, we know that natural faults are not planar, but instead have roughness that can be approximated by power laws potentially leading to large, multiscale fluctuations in normal stress. The capacity to perform 3D rupture simulations that couple these processes willmore » provide guidance for constructing appropriate source models for high-frequency ground motion simulations. The improved rupture models from our multi-scale dynamic rupture simulations will be used to conduct physicsbased (3D waveform modeling-based) probabilistic seismic hazard analysis (PSHA) for California. These calculation will provide numerous important seismic hazard results, including a state-wide extended earthquake rupture forecast with rupture variations for all significant events, a synthetic seismogram catalog for thousands of scenario events and more than 5000 physics-based seismic hazard curves for California.« less

Classification accuracy on the family planning participation status using kernel discriminant analysis

NASA Astrophysics Data System (ADS)

Kurniawan, Dian; Suparti; Sugito

2018-05-01

Population growth in Indonesia has increased every year. According to the population census conducted by the Central Bureau of Statistics (BPS) in 2010, the population of Indonesia has reached 237.6 million people. Therefore, to control the population growth rate, the government hold Family Planning or Keluarga Berencana (KB) program for couples of childbearing age. The purpose of this program is to improve the health of mothers and children in order to manifest prosperous society by controlling births while ensuring control of population growth. The data used in this study is the updated family data of Semarang city in 2016 that conducted by National Family Planning Coordinating Board (BKKBN). From these data, classifiers with kernel discriminant analysis will be obtained, and also classification accuracy will be obtained from that method. The result of the analysis showed that normal kernel discriminant analysis gives 71.05 % classification accuracy with 28.95 % classification error. Whereas triweight kernel discriminant analysis gives 73.68 % classification accuracy with 26.32 % classification error. Using triweight kernel discriminant for data preprocessing of family planning participation of childbearing age couples in Semarang City of 2016 can be stated better than with normal kernel discriminant.

Preliminary Pseudo 3-D Imagery of the State Line Fault, Stewart Valley, Nevada Using Seismic Reflection Data

NASA Astrophysics Data System (ADS)

Saldaña, S. C.; Snelson, C. M.; Taylor, W. J.; Beachly, M.; Cox, C. M.; Davis, R.; Stropky, M.; Phillips, R.; Robins, C.; Cothrun, C.

2007-12-01

The Pahrump Fault system is located in the central Basin and Range region and consists of three main fault zones: the Nopah range front fault zone, the State Line fault zone and the Spring Mountains range fault zone. The State Line fault zone is made up north-west trending dextral strike-slip faults that run parallel to the Nevada- California border. Previous geologic and geophysical studies conducted in and around Stewart Valley, located ~90 km from Las Vegas, Nevada, have constrained the location of the State Line fault zone to within a few kilometers. The goals of this project were to use seismic methods to definitively locate the northwestern most trace of the State Line fault and produce pseudo 3-D seismic cross-sections that can then be used to characterize the subsurface geometry and determine the slip of the State Line fault. During July 2007, four seismic lines were acquired in Stewart Valley: two normal and two parallel to the mapped traces of the State Line fault. Presented here are preliminary results from the two seismic lines acquired normal to the fault. These lines were acquired utilizing a 144-channel geode system with each of the 4.5 Hz vertical geophones set out at 5 m intervals to produce a 595 m long profile to the north and a 715 m long profile to the south. The vibroseis was programmed to produce an 8 s linear sweep from 20-160 Hz. These data returned excellent signal to noise and reveal subsurface lithology that will subsequently be used to resolve the subsurface geometry of the State Line fault. This knowledge will then enhance our understanding of the evolution of the State Line fault. Knowing how the State Line fault has evolved gives insight into the stick-slip fault evolution for the region and may improve understanding of how stress has been partitioned from larger strike-slip systems such as the San Andreas fault.

Eating Habits and Food Additive Intakes Are Associated with Emotional States Based on EEG and HRV in Healthy Korean Children and Adolescents.

PubMed

Kim, Jin Young; Kang, Hye Lim; Kim, Dae-Keun; Kang, Seung Wan; Park, Yoo Kyoung

2017-07-01

Recent study suggests that psychological issues and eating habits are closely related. In this study, we aimed to find the association between eating habits and intakes of artificial sweeteners with emotional states of schoolchildren using quantitatively analyzing objective biosignals. The study was conducted at the National Standard Reference Data Center for Korean EEG as a cross-sectional study. Three hundred eighteen healthy children who have not been diagnosed with neurologic or psychiatric disorders were evaluated (168 girls and 150 boys; mean age of 11.8 ± 3.6 years). Analysis indicators were a dietary intake checklist for children's nutrition-related behavior score (NBS), consisting of 19 items; food frequency questionnaires (FFQs), consisting of 76 items; the Child Depression Inventory (CDI); State-Trait Anxiety Inventory-State (STAI-S); State-Trait Anxiety Inventory-Trait (STAI-T); electroencephalograph (EEG); and heart rate variability (HRV). Higher scores on the CDI, STAI-S, and STAI-T indicate negative emotions, and these scores were significantly decreased from the first to the fourth quartiles. The HRV results showed that the standard deviation of all normal-to-normal (SDNN) intervals was significantly higher in the first quartile than in the fourth quartile (p < 0.05). The intakes of artificial sweeteners and processed foods such as hamburgers correlate with higher theta/beta ratios, and intakes of natural foods such as legumes and fruits correlate with lower theta/beta ratios (p < 0.05). From this result we confirmed a link between overall nutritional behavior, food additive intakes, and emotion in apparently healthy children and adolescents.

Evolution of superconducting gap and metallic ground state in cuprates from transport

NASA Astrophysics Data System (ADS)

Taillefer, Louis

2006-03-01

We report on fundamental characteristics of the ground state of cuprates in the limit of T=0, for both normal and superconducting states, obtained from transport measurements on high-quality single crystals of YBCO and Tl-2201, as a function of hole concentration. The superconducting gap is extracted from thermal conductivity; it is found to scale with the superconducting transition temperature throughout the overdoped regime, with a gap-to-Tc ratio of 5 [1]. The normal state is accessed by suppressing superconductivity with magnetic fields up to 60 T and is characterized by the limiting behavior of its electrical resistivity; while carrier localization is observed in YBCO at low temperature for carrier concentrations p below 0.1 hole/planar Cu, at p=0.1 and above the material remains highly metallic down to T=0 [2]. This shows that the non-superconducting state of underdoped cuprates, deep in the pseudogap phase, is remarkably similar to that of strongly overdoped cuprates, e.g. at p=0.3. We compare these results with similar measurements on other cuprates and discuss their implication for our understanding of the cuprate phase diagram. [1] In collaboration with: D.G. Hawthorn, S.Y. Li, M. Sutherland, E. Boaknin, R.W. Hill, C. Proust, F. Ronning, M. Tanatar, J. Paglione, D. Peets, R. Liang, D.A. Bonn, W.N. Hardy, and N.N. Kolesnikov. [2] In collaboration with: C. Proust, M. Sutherland, N. Doiron- Leyraud, S.Y. Li, R. Liang, D.A. Bonn, W.N. Hardy, N.E. Hussey, S. Adachi, S. Tajima, J. Levallois, and M. Narbone.

Optical spectroscopy study of the three-dimensional Dirac semimetal ZrTe 5

DOE PAGES

Chen, R. Y.; Gu, G. D.; Zhang, S. J.; ...

2015-08-05

Three-dimensional (3D) topological Dirac materials have been under intensive study recently. The layered compound ZrTe 5 has been suggested to be one such material as a result of transport and angle-resolved photoemission spectroscopy experiments. Here, we perform infrared reflectivity measurements to investigate the underlying physics of this material. The derived optical conductivity increases linearly with frequency below normal interband transitions, which provides optical spectroscopic proof of a 3D Dirac semimetal. In addition, the plasma edge shifts dramatically to lower energy upon temperature cooling, which might be due to the shrinking of the lattice parameters. Additionally, an extremely sharp peak showsmore » up in the frequency-dependent optical conductivity, indicating the presence of a Van Hove singularity in the joint density of state.« less

Circadian changes in salivary constituents and conductivity in women and men.

PubMed

Atwood, C S; James, I R; Keil, U; Roberts, N K; Hartmann, P E

1991-01-01

Circadian rhythms in salivary [glucose], [Na+], [K+] and conductivity were measured in 2 age groups of men (men A, 20-45 years and men B, 46-60 years) and 8 different states of fertility in women (normally menstruating, taking oral contraceptives, pregnant, lactational amenorrhea, lactational amenorrhea and taking oral contraceptives, lactating and menstruating, menopausal, and post-menopausal). Unstimulated whole saliva (2-3 ml) was collected every 3 h over a 48 h span. Analysis of Spearman Rank Correlations indicated significant circadian rhythms (significant positive coefficients) for all groups of [Na+] (mean = 0.577 +/- 0.040) and conductivity (mean = 0.410 +/- 0.050). There was no evidence of differences in prominence of rhythm across groups for [Na+] and conductivity. [K+] showed less evidence of rhythms and much greater variability between groups (mean correlation coefficient = 0.198 +/- 0.055). Rhythms in [glucose] (mean correlation coefficient = 0.409 +/- 0.051) were evident in all groups except men B (0.016), menopausal women (0.151) and post-menopausal women (0.310). Model analysis of the data showed no discernible rhythmic trend with age for either conductivity, [Na+] or [K+], where any differences were explainable by the group characteristics. The rhythm in [glucose] showed a significant weakening with age over all groups (F-ratio = 7.46**), and was different between men A and men B (F-ratio = 6.95**). It was concluded that circadian rhythms were present in whole unstimulated saliva for conductivity and [Na+] and that these rhythms were independent of reproductive state, whereas circadian rhythms in [K+] were dependent on reproductive state. Circadian rhythms for [glucose] were dependent on age. The loss of a rhythm in [glucose] with age indicates that glucose, Na+ and K+ are not linked in their entry into saliva. The influence of entry and reabsorption on the final concentrations of glucose, Na+ and K+ in saliva is discussed.

Quantifying the underlying landscape and paths of cancer

PubMed Central

Li, Chunhe; Wang, Jin

2014-01-01

Cancer is a disease regulated by the underlying gene networks. The emergence of normal and cancer states as well as the transformation between them can be thought of as a result of the gene network interactions and associated changes. We developed a global potential landscape and path framework to quantify cancer and associated processes. We constructed a cancer gene regulatory network based on the experimental evidences and uncovered the underlying landscape. The resulting tristable landscape characterizes important biological states: normal, cancer and apoptosis. The landscape topography in terms of barrier heights between stable state attractors quantifies the global stability of the cancer network system. We propose two mechanisms of cancerization: one is by the changes of landscape topography through the changes in regulation strengths of the gene networks. The other is by the fluctuations that help the system to go over the critical barrier at fixed landscape topography. The kinetic paths from least action principle quantify the transition processes among normal state, cancer state and apoptosis state. The kinetic rates provide the quantification of transition speeds among normal, cancer and apoptosis attractors. By the global sensitivity analysis of the gene network parameters on the landscape topography, we uncovered some key gene regulations determining the transitions between cancer and normal states. This can be used to guide the design of new anti-cancer tactics, through cocktail strategy of targeting multiple key regulation links simultaneously, for preventing cancer occurrence or transforming the early cancer state back to normal state. PMID:25232051

From Intensity Profile to Surface Normal: Photometric Stereo for Unknown Light Sources and Isotropic Reflectances.

PubMed

Lu, Feng; Matsushita, Yasuyuki; Sato, Imari; Okabe, Takahiro; Sato, Yoichi

2015-10-01

We propose an uncalibrated photometric stereo method that works with general and unknown isotropic reflectances. Our method uses a pixel intensity profile, which is a sequence of radiance intensities recorded at a pixel under unknown varying directional illumination. We show that for general isotropic materials and uniformly distributed light directions, the geodesic distance between intensity profiles is linearly related to the angular difference of their corresponding surface normals, and that the intensity distribution of the intensity profile reveals reflectance properties. Based on these observations, we develop two methods for surface normal estimation; one for a general setting that uses only the recorded intensity profiles, the other for the case where a BRDF database is available while the exact BRDF of the target scene is still unknown. Quantitative and qualitative evaluations are conducted using both synthetic and real-world scenes, which show the state-of-the-art accuracy of smaller than 10 degree without using reference data and 5 degree with reference data for all 100 materials in MERL database.

SymPS: BRDF Symmetry Guided Photometric Stereo for Shape and Light Source Estimation.

PubMed

Lu, Feng; Chen, Xiaowu; Sato, Imari; Sato, Yoichi

2018-01-01

We propose uncalibrated photometric stereo methods that address the problem due to unknown isotropic reflectance. At the core of our methods is the notion of "constrained half-vector symmetry" for general isotropic BRDFs. We show that such symmetry can be observed in various real-world materials, and it leads to new techniques for shape and light source estimation. Based on the 1D and 2D representations of the symmetry, we propose two methods for surface normal estimation; one focuses on accurate elevation angle recovery for surface normals when the light sources only cover the visible hemisphere, and the other for comprehensive surface normal optimization in the case that the light sources are also non-uniformly distributed. The proposed robust light source estimation method also plays an essential role to let our methods work in an uncalibrated manner with good accuracy. Quantitative evaluations are conducted with both synthetic and real-world scenes, which produce the state-of-the-art accuracy for all of the non-Lambertian materials in MERL database and the real-world datasets.

In vivo electrical conductivity of hepatic tumours.

PubMed

Haemmerich, Dieter; Staelin, S T; Tsai, J Z; Tungjitkusolmun, S; Mahvi, D M; Webster, J G

2003-05-01

Knowledge of electrical tissue conductivity is necessary to determine deposition of electromagnetic energy and can further be used to diagnostically differentiate between normal and neoplastic tissue. We measured 17 rats with a total of 24 tumours of the K12/TRb rat colon cancer cell line. In each animal we measured in vivo hepatic tumour and normal tissue conductivity at seven frequencies from 10 Hz to 1 MHz, at different tumour stages between 6 and 12 weeks after induction. Conductivity of normal liver tissue was 1.26 +/- 0.15 mS cm(-1) at 10 Hz, and 4.61 +/- 0.42 mS cm(-1) at 1 MHz. Conductivity of tumour was 2.69 +/- 0.91 mS cm(-1) at 10 Hz, and 5.23 +/- 0.82 mS cm(-1) at 1 MHz. Conductivity was significantly different between normal and tumour tissue (p < 0.05). We determined the percentage of necrosis and fibrosis at the measurement site. We fitted the conductivity data to the Cole-Cole model. For the tumour data we determined Spearman's correlation coefficients between the Cole-Cole parameters and age, necrosis, fibrosis and tumour volume and found significant correlation between necrosis and the Cole-Cole parameters (p < 0.05). We conclude that necrosis within the tumour and the associated membrane breakdown is likely responsible for the observed change in conductivity.

The Functionality of Facial Appearance and Its Importance to a Korean Population

PubMed Central

Kim, Young Jun; Park, Jang Wan; Kim, Jeong Min; Park, Sun Hyung; Hwang, Jae Ha; Lee, Sam Yong; Shin, Jun Ho

2013-01-01

Background Many people have an interest in the correction of facial scars or deformities caused by trauma. The increasing ability to correct such flaws has been one of the reasons for the increase in the popularity of facial plastic surgery. In addition to its roles in communication, breathing, eating, olfaction and vision, the appearance of the face also plays an important role in human interactions, including during social activities. However, studies on the importance of the functional role of facial appearance. As a function of the face are scare. Therefore, in the present study, we evaluated the importance of the functions of the face in Korea. Methods We conducted an online panel survey of 300 participants (age range, 20-70 years). Each respondent was administered the demographic data form, Facial Function Assessment Scale, Rosenberg Self-Esteem Scale, and standard gamble questionnaires. Results In the evaluation on the importance of facial functions, a normal appearance was considered as important as communication, breathing, speech, and vision. Of the 300 participants, 85% stated that a normal appearance is important in social activities. Conclusions The results of this survey involving a cross-section of the Korean population indicated that a normal appearance was considered one of the principal facial functions. A normal appearance was considered more important than the functions of olfaction and expression. Moreover, a normal appearance was determined to be an important facial function for leading a normal life in Korea. PMID:24286044

A model of the normal and null states of pulsars

NASA Astrophysics Data System (ADS)

Jones, P. B.

1981-12-01

A solvable three-dimensional polar cap model of pair creation and charged particle acceleration has been derived. There are no free parameters of significance apart from the polar surface magnetic flux density. The parameter determining the acceleration potential difference has been obtained by calculation of elementary nuclear and electromagnetic processes. Solutions of the model exist for both normal and null states of a pulsar, and the instability in the normal state leading to the normal to null transition has been identified. The predicted necessary condition for the transition is entirely consistent with observation.

A model of the normal and null states of pulsars

NASA Astrophysics Data System (ADS)

Jones, P. B.

A solvable three dimensional polar cap model of pair creation and charged particle acceleration is derived. There are no free parameters of significance apart from the polar surface magnetic flux density. The parameter CO determining the acceleration potential difference was obtained by calculation of elementary nuclear and electromagnetic processes. Solutions of the model exist for both normal and null states of a pulsar, and the instability in the normal state leading to the normal to null transition is identified. The predicted necessary condition for the transition is entirely consistent with observation.

Anomalous Hall effect in semiconductor quantum wells in proximity to chiral p -wave superconductors

NASA Astrophysics Data System (ADS)

Yang, F.; Yu, T.; Wu, M. W.

2018-05-01

By using the gauge-invariant optical Bloch equation, we perform a microscopic kinetic investigation on the anomalous Hall effect in chiral p -wave superconducting states. Specifically, the intrinsic anomalous Hall conductivity in the absence of the magnetic field is zero as a consequence of Galilean invariance in our description. As for the extrinsic channel, a finite anomalous Hall current is obtained from the impurity scattering with the optically excited normal quasiparticle current even at zero temperature. From our kinetic description, it can be clearly seen that the excited normal quasiparticle current is due to an induced center-of-mass momentum of Cooper pairs through the acceleration driven by ac electric field. For the induced anomalous Hall current, we show that the conventional skew-scattering channel in the linear response makes the dominant contribution in the strong impurity interaction. In this case, our kinetic description as a supplementary viewpoint mostly confirms the results of Kubo formalism in the literature. Nevertheless, in the weak impurity interaction, this skew-scattering channel becomes marginal and we reveal that an induction channel from the Born contribution dominates the anomalous Hall current. This channel, which has long been overlooked in the literature, is due to the particle-hole asymmetry by nonlinear optical excitation. Finally, we study the case in the chiral p -wave superconducting state with a transverse conical magnetization, which breaks the Galilean invariance. In this situation, the intrinsic anomalous Hall conductivity is no longer zero. Comparison of this intrinsic channel with the extrinsic one from impurity scattering is addressed.

New perspectives concerning feedback influences on cardiorespiratory control during rhythmic exercise and on exercise performance

PubMed Central

Dempsey, Jerome A

2012-01-01

The cardioaccelerator and ventilatory responses to rhythmic exercise in the human are commonly viewed as being mediated predominantly via feedforward ‘central command’ mechanisms, with contributions from locomotor muscle afferents to the sympathetically mediated pressor response. We have assessed the relative contributions of three types of feedback afferents on the cardiorespiratory response to voluntary, rhythmic exercise by inhibiting their normal ‘tonic’ activity in healthy animals and humans and in chronic heart failure. Transient inhibition of the carotid chemoreceptors during moderate intensity exercise reduced muscle sympathetic nerve activity (MSNA) and increased limb vascular conductance and blood flow; and reducing the normal level of respiratory muscle work during heavier intensity exercise increased limb vascular conductance and blood flow. These cardiorespiratory effects were prevented via ganglionic blockade and were enhanced in chronic heart failure and in hypoxia. Blockade of μ opioid sensitive locomotor muscle afferents, with preservation of central motor output via intrathecal fentanyl: (a) reduced the mean arterial blood pressure (MAP), heart rate and ventilatory responses to all steady state exercise intensities; and (b) during sustained high intensity exercise, reduced O2 transport, increased central motor output and end-exercise muscle fatigue and reduced endurance performance. We propose that these three afferent reflexes – probably acting in concert with feedforward central command – contribute significantly to preserving O2 transport to locomotor and to respiratory muscles during exercise. Locomotor muscle afferents also appear to provide feedback concerning the metabolic state of the muscle to influence central motor output, thereby limiting peripheral fatigue development. PMID:22826128

Band structure of the quasi two-dimensional purple molybdenum bronze

NASA Astrophysics Data System (ADS)

Guyot, H.; Balaska, H.; Perrier, P.; Marcus, J.

2006-09-01

The molybdenum purple bronze KMo 6O 17 is quasi two-dimensional (2D) metallic oxide that shows a Peierls transition towards a metallic charge density wave state. Since this specific transition is directly related to the electron properties of the normal state, we have investigated the electronic structure of this bronze at room temperature. The shape of the Mo K1s absorption edge reveals the presence of distorted MoO 6 octahedra in the crystallographic structure. Photoemission experiments evidence a large conduction band, with a bandwidth of 800 meV and confirm the metallic character of this bronze. A wide depleted zone separates the conduction band from the valence band that exhibits a fourfold structure, directly connected to the octahedral symmetry of the Mo sites. The band structure is determined by ARUPS in two main directions of the (0 0 1) Brillouin zone. It exhibits some unpredicted features but corroborates the earlier theoretical band structure and Fermi surface. It confirms the hidden one-dimensionality of KMo 6O 17 that has been proposed to explain the origin of the Peierls transition in this 2D compound.

Selection of housekeeping genes for gene expression studies in the adult rat submandibular gland under normal, inflamed, atrophic and regenerative states

PubMed Central

Silver, Nicholas; Cotroneo, Emanuele; Proctor, Gordon; Osailan, Samira; Paterson, Katherine L; Carpenter, Guy H

2008-01-01

Background Real-time PCR is a reliable tool with which to measure mRNA transcripts, and provides valuable information on gene expression profiles. Endogenous controls such as housekeeping genes are used to normalise mRNA levels between samples for sensitive comparisons of mRNA transcription. Selection of the most stable control gene(s) is therefore critical for the reliable interpretation of gene expression data. For the purpose of this study, 7 commonly used housekeeping genes were investigated in salivary submandibular glands under normal, inflamed, atrophic and regenerative states. Results The program NormFinder identified the suitability of HPRT to use as a single gene for normalisation within the normal, inflamed and regenerative states, and GAPDH in the atrophic state. For normalisation to multiple housekeeping genes, for each individual state, the optimal number of housekeeping genes as given by geNorm was: ACTB/UBC in the normal, ACTB/YWHAZ in the inflamed, ACTB/HPRT in the atrophic and ACTB/GAPDH in the regenerative state. The most stable housekeeping gene identified between states (compared to normal) was UBC. However, ACTB, identified as one of the most stably expressed genes within states, was found to be one of the most variable between states. Furthermore we demonstrated that normalising between states to ACTB, rather than UBC, introduced an approximately 3 fold magnitude of error. Conclusion Using NormFinder, our studies demonstrated the suitability of HPRT to use as a single gene for normalisation within the normal, inflamed and regenerative groups and GAPDH in the atrophic group. However, if normalising to multiple housekeeping genes, we recommend normalising to those identified by geNorm. For normalisation across the physiological states, we recommend the use of UBC. PMID:18637167

Asymmetric Andreev resonant state with a magnetic exchange field in spin-triplet superconducting monolayer MoS2

NASA Astrophysics Data System (ADS)

Goudarzi, H.; Khezerlou, M.; Ebadzadeh, S. F.

2018-03-01

We study the influence of magnetic exchange field (MEF) on the chirality of Andreev resonant state (ARS) appearing at the relating monolayer MoS2 ferromagnet/superconductor interface, in which the induced pairing order parameter is chiral p-wave symmetry. Transmission of low-energy Dirac-like electron (hole) quasiparticles through a ferromagnet/superconductor (F/S) interface is considered based on Dirac-Bogoliubov-de Gennes Hamiltonian and, of course, Andreev reflection process. The magnetic exchange field of a ferromagnetic section on top of ML-MDS may affect the electron (hole) excitations for spin-up and spin-down electrons, differently. We find the chirality symmetry of ARS to be conserved in the absence of MEF, whereas it is broken in the presence of MEF. Tuning the MEF enables one to control either electrical properties (such as band gap, SOC and etc.) or spin-polarized transport. The resulting normal conductance is found to be more sensitive to the magnitude of MEF and doping regime of F region. Unconventional spin-triplet p-wave symmetry features the zero-bias conductance, which strongly depends on p-doping level of F region in the relating NFS junction. A sharp conductance switching in zero is achieved in the absence of SOC.

Antibacterial Efficacy of Tender Coconut Water (Cocos nucifera L) on Streptococcus mutans: An In-Vitro Study

PubMed Central

Rukmini, J. N.; Manasa, Sunkari; Rohini, Chenna; Sireesha, Lavanya Putchla; Ritu, Sachan; Umashankar, G. K.

2017-01-01

Objective: The antibacterial property of coconut, the presence of lauric acid, and the ability to extract antimicrobial peptides Cn-AMP (1, 2, and 3) from tender coconut water has drawn attention on its effectiveness in normal consumption. An in-vitro experimental study was conducted to evaluate the antimicrobial efficacy of tender coconut water in its natural state on Streptococcus mutans. Materials and Methods: Fresh tender coconut water and pasteurized tender coconut water were taken as test samples, dimethyl formamide was used as the negative control, and 0.2% chlorhexidine was used as the positive control. Pure strain of S. mutans (MTCC 890) was used for determining the antibacterial effects. The test samples along with the controls were subjected to antimicrobial sensitivity test procedure and the zone of inhibition was examined. Kruskal–Wallis test was used to check for any significant differences in the antibacterial efficacy between the samples. Result: There was no zone of inhibition with the tender coconut water, fresh and pasteurised, and negative control (dimethyl formamide). Zone of inhibition was seen in positive control (0.2% Chlorhexidine). Conclusion: No antimicrobial activity was demonstrated with tender coconut water in its normal state (in vitro). PMID:28462183

Antibacterial Efficacy of Tender Coconut Water (Cocos nucifera L) on Streptococcus mutans: An In-Vitro Study.

PubMed

Rukmini, J N; Manasa, Sunkari; Rohini, Chenna; Sireesha, Lavanya Putchla; Ritu, Sachan; Umashankar, G K

2017-01-01

The antibacterial property of coconut, the presence of lauric acid, and the ability to extract antimicrobial peptides Cn-AMP (1, 2, and 3) from tender coconut water has drawn attention on its effectiveness in normal consumption. An in-vitro experimental study was conducted to evaluate the antimicrobial efficacy of tender coconut water in its natural state on Streptococcus mutans . Fresh tender coconut water and pasteurized tender coconut water were taken as test samples, dimethyl formamide was used as the negative control, and 0.2% chlorhexidine was used as the positive control. Pure strain of S. mutans (MTCC 890) was used for determining the antibacterial effects. The test samples along with the controls were subjected to antimicrobial sensitivity test procedure and the zone of inhibition was examined. Kruskal-Wallis test was used to check for any significant differences in the antibacterial efficacy between the samples. There was no zone of inhibition with the tender coconut water, fresh and pasteurised, and negative control (dimethyl formamide). Zone of inhibition was seen in positive control (0.2% Chlorhexidine). No antimicrobial activity was demonstrated with tender coconut water in its normal state ( in vitro ).

Effects of premature stimulation on HERG K+ channels

PubMed Central

Lu, Yu; Mahaut-Smith, Martyn P; Varghese, Anthony; Huang, Christopher L-H; Kemp, Paul R; Vandenberg, Jamie I

2001-01-01

The unusual kinetics of human ether-à-go-go-related gene (HERG) K+ channels are consistent with a role in the suppression of arrhythmias initiated by premature beats. Action potential clamp protocols were used to investigate the effect of premature stimulation on HERG K+ channels, transfected in Chinese hamster ovary cells, at 37 °C. HERG K+ channel currents peaked during the terminal repolarization phase of normally paced action potential waveforms. However, the magnitude of the current and the time point at which conductance was maximal depended on the type of action potential waveform used (epicardial, endocardial, Purkinje fibre or atrial). HERG K+ channel currents recorded during premature action potentials consisted of an early transient outward current followed by a sustained outward current. The magnitude of the transient current component showed a biphasic dependence on the coupling interval between the normally paced and premature action potentials and was maximal at a coupling interval equivalent to 90% repolarization (APD90) for ventricular action potentials. The largest transient current response occurred at shorter coupling intervals for Purkinje fibre (APD90– 20 ms) and atrial (APD90– 30 ms) action potentials. The magnitude of the sustained current response following premature stimulation was similar to that recorded during the first action potential for ventricular action potential waveforms. However, for Purkinje and atrial action potentials the sustained current response was significantly larger during the premature action potential than during the normally paced action potential. A Markov model that included three closed states, one open and one inactivated state with transitions permitted between the pre-open closed state and the inactivated state, successfully reproduced our results for the effects of premature stimuli, both during square pulse and action potential clamp waveforms. These properties of HERG K+ channels may help to suppress arrhythmias initiated by early afterdepolarizations and premature beats in the ventricles, Purkinje fibres or atria. PMID:11744759

A comparison of the effects of caffeine following abstinence and normal caffeine use.

PubMed

Addicott, Merideth A; Laurienti, Paul J

2009-12-01

Caffeine typically produces positive effects on mood and performance. However, tolerance may develop following habitual use, and abrupt cessation can result in withdrawal symptoms, such as fatigue. This study investigated whether caffeine has a greater stimulant effect in a withdrawn state compared to a normal caffeinated state, among moderate daily caffeine consumers. Using a within-subjects design, 17 caffeine consumers (mean +/- sd = 375 +/- 101 mg/day) ingested placebo or caffeine (250 mg) following 30-h of caffeine abstention or normal dietary caffeine use on four separate days. Self-reported mood and performance on choice reaction time, selective attention, and memory tasks were measured. Caffeine had a greater effect on mood and choice reaction time in the abstained state than in the normal caffeinated state, but caffeine improved selective attention and memory in both states. Although improvements in mood and reaction time may best explained as relief from withdrawal symptoms, other performance measures showed no evidence of withdrawal and were equally sensitive to an acute dose of caffeine in the normal caffeinated state.

A comparison of the effects of caffeine following abstinence and normal caffeine use

PubMed Central

Addicott, Merideth A.

2010-01-01

Rationale Caffeine typically produces positive effects on mood and performance. However, tolerance may develop following habitual use, and abrupt cessation can result in withdrawal symptoms, such as fatigue. This study investigated whether caffeine has a greater stimulant effect in a withdrawn state compared to a normal caffeinated state, among moderate daily caffeine consumers. Materials and methods Using a within-subjects design, 17 caffeine consumers (mean±sd=375±101 mg/day) ingested placebo or caffeine (250 mg) following 30-h of caffeine abstention or normal dietary caffeine use on four separate days. Self-reported mood and performance on choice reaction time, selective attention, and memory tasks were measured. Results Caffeine had a greater effect on mood and choice reaction time in the abstained state than in the normal caffeinated state, but caffeine improved selective attention and memory in both states. Conclusions Although improvements in mood and reaction time may best explained as relief from withdrawal symptoms, other performance measures showed no evidence of withdrawal and were equally sensitive to an acute dose of caffeine in the normal caffeinated state. PMID:19777214

Ideologies of self, suffering, and gender nonconformity at work in a US gender identity clinic.

PubMed

van Eijk, Marieke

2014-01-01

Health care institutions are often severely criticized for regulating the lives of individuals who deviate from socially sanctioned norms. In teaching people where they fit in the conventional scheme of things, institutions often reproduce socially dominant ideologies of normality, health, and self. Drawing on ethnographic fieldwork conducted at a university-based gender identity clinic in the United States, I demonstrate that while some institutions adopt dominant cultural frameworks, others critically assess these. To understand the intricacies of the clinic's psychotherapeutic practices, I analyze the clinicians' constructions of health and suffering. Instead of viewing transgenderism as a psychiatric condition, these clinicians approach it as a normal human condition that is marginalized by society's heteronormative values. The analysis, attentive to the interaction among social context, institutional work, and psychotherapeutic ideologies, shows that while some institutions reproduce hegemonic cultural frameworks, others, in their attempts to alleviate people's suffering, do challenge dominant social norms.

What Teens Want: Barriers to Seeking Care for Depression

PubMed Central

Wisdom, Jennifer P.; Clarke, Gregory N.; Green, Carla A.

2013-01-01

This study examined the experiences of teenagers seeking and receiving care for depression from primary care providers. We investigated teens’ perceived barriers in obtaining care to determine how primary care can effectively address depressed teens’ stated needs. In-depth individual (n = 15) and focus group (n = 7) interviews with adolescents were conducted and analyzed using grounded theory and prominent themes were identified. Teenagers reported faring best when providers actively considered and reflected upon the teenagers’ developmentally appropriate desires to be normal, to feel connected, and to be autous. These goals are achieved by providers establishing rapport, exchanging information about depression etiology and treatment, and helping teens make decisions about their treatment. To the extent that providers improve efforts to help teens feel normal, autonomous, and connected, the teens report they are more likely to accept treatment for depression and report success in treatment. PMID:16489480

Definition and management of hypertension among Haitian immigrants: a qualitative study.

PubMed

Sanon, Marie-Anne; Mohammed, Selina A; McCullagh, Marjorie C

2014-08-01

Hypertension is a major health concern among Haitian immigrants, one of the largest Caribbean immigrant groups in the United States. Yet, little is known about how Hatian immigrants define and manage hypertension. For this qualitative study, face-to-face semi-structured interviews were conducted with 31 Haitian immigrants in Miami Dade County, Florida. Results indicated that most Haitian immigrants used the Haitian Creole word tansyon to represent hypertension. Tansyon was considered as either a normal condition of the human body or a maladi (illness). Both traditional biomedical and alternative approaches were used to manage hypertension. The findings show that how Haitian immigrants defined hypertension shaped their beliefs about its occurrence and the resulting management strategies used. Those who believed tansyon was a normal body condition did not take any management measures. Awareness and understanding of Haitian immigrants' beliefs about and approaches to hypertension management can enhance culturally sensitive care and improve health outcomes.

IVGEN Post Flight Analysis

NASA Technical Reports Server (NTRS)

Mcquillen, John; Brown, Dan; Hussey, Sam; Zoldak, John

2014-01-01

The Intravenous Fluid Generation (IVGEN) Experiment was a technology demonstration experiment that purified ISS potable water, mixed it with salt, and transferred it through a sterilizing filter. On-orbit performance was verified as appropriate and two 1.5 l bags of normal saline solution were returned to earth for post-flight testing by a FDA certified laboratory for compliance with United States Pharmacopiea (USP) standards. Salt concentration deviated from required values and an analysis identified probable causes. Current efforts are focused on Total Organic Content (TOC) testing, and shelf life.The Intravenous Fluid Generation (IVGEN) Experiment demonstrated the purification of ISS potable water, the mixing of the purified water with sodium chloride, and sterilization of the solution via membrane filtration. On-orbit performance was monitored where feasible and two 1.5-liter bags of normal saline solution were returned to earth for post-flight testing by a FDA-registered laboratory for compliance with United States Pharmacopeia (USP)standards [1]. Current efforts have been focused on challenge testing with identified [2] impurities (total organic-carbon), and shelf life testing. The challenge testing flowed known concentrations of contaminants through the IVGEN deionizing cartridge and membrane filters to test their effectiveness. One finding was that the filters and DI-resin themselves contribute to the contaminant load during initial startup, suggesting that the first 100 ml of fluid be discarded. Shelf life testing is ongoing and involves periodic testing of stored DI cartridges and membrane filters that are capped and sealed in hermetic packages. The testing is conducted at six month intervals measuring conductivity and endotoxins in the effluent. Currently, the packaging technique has been successfully demonstrated for one year of storage testing. The USP standards specifies that the TOC be conducted at point of generation as opposed to point of consumption. Samples were generated and shipped to an FDA facility however, testing determined that the samples failed the TOC specification with most likely due to leaching from the sample container. Shelf life testing is examining packaging techniques and periodic testing of samples of DI cartridges that are capped and sealed in hermetic packages. Periodic testing of the purified water output will be conducted at six month intervals.

Superconducting cuprate heterostructures for hot electron bolometers

NASA Astrophysics Data System (ADS)

Wen, B.; Yakobov, R.; Vitkalov, S. A.; Sergeev, A.

2013-11-01

Transport properties of the resistive state of quasi-two dimensional superconducting heterostructures containing ultrathin La2-xSrxCuO4 layers synthesized using molecular beam epitaxy are studied. The electron transport exhibits strong deviation from Ohm's law, δV ˜γI3, with a coefficient γ(T) that correlates with the temperature variation of the resistivity dρ /dT. Close to the normal state, analysis of the nonlinear behavior in terms of electron heating yields an electron-phonon thermal conductance per unit area ge -ph≈1 W/K cm2 at T = 20 K, one-two orders of magnitude smaller than in typical superconductors. This makes superconducting LaSrCuO heterostructures to be attractive candidate for the next generation of hot electron bolometers with greatly improved sensitivity.

Preliminary results of steady state characterization of near term electric vehicle breadboard propulsion system

NASA Technical Reports Server (NTRS)

Sargent, N. B.

1980-01-01

The steady state test results on a breadboard version of the General Electric Near Term Electric Vehicle (ETV-1) are discussed. The breadboard was built using exact duplicate vehicle propulsion system components with few exceptions. Full instrumentation was provided to measure individual component efficiencies. Tests were conducted on a 50 hp dynamometer in a road load simulator facility. Characterization of the propulsion system over the lower half of the speed-torque operating range has shown the system efficiency to be composed of a predominant motor loss plus a speed dependent transaxle loss. At the lower speeds with normal road loads the armature chopper loss is also a significant factor. At the conditions corresponding to a cycle for which the vehicle system was specifically designed, the efficiencies are near optimum.

Quantum-Fluctuation Effects in the Transport Properties of Ultrathin Films of Disordered Superconductors above the Paramagnetic Limit

NASA Astrophysics Data System (ADS)

Khodas, M.; Levchenko, A.; Catelani, G.

2012-06-01

We study the transport in ultrathin disordered film near the quantum critical point induced by the Zeeman field. We calculate corrections to the normal state conductivity due to quantum pairing fluctuations. The fluctuation-induced transport is mediated by virtual rather than real quasiparticle excitations. We find that at zero temperature, where the corrections come from purely quantum fluctuations, the Aslamazov-Larkin paraconductivity term, the Maki-Thompson interference contribution, and the density of states effects are all of the same order. The total correction leads to the negative magnetoresistance. This result is in qualitative agreement with the recent transport observations in the parallel magnetic field of the homogeneously disordered amorphous films and superconducting two-dimensional electron gas realized at the oxide interfaces.

Effect of second to first normal stress difference ratio at the die exit on neck-in phenomenon in polymeric flat film production

NASA Astrophysics Data System (ADS)

Barborik, Tomas; Zatloukal, Martin

2017-05-01

In this study, viscoelastic modeling of the extrusion film casting process, based on the lD membrane model and modified Leonov constitutive equation, was conducted and the effect of the viscoelastic stress state at the die exit (captured here via second to first normal stress difference ratio) on the unwanted neck-in phenomenon has been analyzed for wide range of Deborah numbers and materials having different level of uniaxial and planar extensional strain hardening. Relevant experimental data for LDPE and theoretical predictions based on multimode eXtended Pom-Pom model acquired from the open literature were used for the validation purposes. It was found that firstly, the predicting capabilities of both constitutive equations for given material and processing conditions are comparable even if the single mode modified Leonov model was used and secondly, the agreement between theoretical and experimental data on neck-in is fairly good. Results of the theoretical study revealed that the viscoelastic stress state at the die exit (i.e. -N2/N1 ratio) increases the level of neck-in if uniaxial extensional strain hardening, planar to uniaxial extensional viscosity ratio and Deborah number increases. It has also been revealed that there exists threshold value for Deborah number and extensional strain hardening below which the neck-in becomes independent on the die exit stress state.

pH-modulation of chloride channels from the sarcoplasmic reticulum of skeletal muscle.

PubMed

Kourie, J I

1999-01-01

The understanding of the role of cytoplasmic pH in modulating sarcoplasmic reticulum (SR) ion channels involved in Ca2+ regulation is important for the understanding of the function of normal and adversely affected muscles. The dependency of the SR small chloride (SCl) channel from rabbit skeletal muscle on cytoplasmic pH (pHcis) and luminal pH (pHtrans) was investigated using the lipid bilayer-vesicle fusion technique. Low pHcis 6.75-4.28 modifies the operational mode of this multiconductance channel (conductance levels between 5 and 75 pS). At pHcis 7.26-7.37 the channel mode is dominated by the conductance and kinetics of the main conductance state (65-75 pS) whereas at low pHcis 6.75-4.28 the channel mode is dominated by the conductance and kinetics of subconductance states (5-40 pS). Similarly, low pHtrans 4.07, but not pHtrans 6.28, modified the activity of SCl channels. The effects of low pHcis are pronounced at 10(-3) and 10(-4) M [Ca2+]cis but are not apparent at 10(-5) M [Ca2+]cis, where the subconductances of the channel are already prominent. Low pHcis-induced mode shift in the SCl channel activity is due to modification of the channel proteins that cause the uncoupling of the subconductance states. The results in this study suggest that low pHcis can modify the functional properties of the skeletal SR ion channels and hence contribute, at least partly, to the malfunction in the contraction-relaxation mechanism in skeletal muscle under low cytoplasmic pH levels.

Chronic inflammatory pure sensory polyradiculoneuropathy: a rare CIDP variant with unusual electrophysiology.

PubMed

Rajabally, Yusuf A; Wong, Siew L

2012-03-01

We describe a patient presenting with progressive upper limb numbness and sensory ataxia of the 4 limbs. Motor nerve conduction studies were completely normal. Sensory electrophysiology showed reduced/absent upper limb sensory action potentials (SAPs). In the lower limbs, SAPs were mostly normal. Sensory conduction velocities were normal. Forearm sensory conduction blocks were present for both median nerves on antidromic testing. The maximal recordable sural SAP was preserved in comparison to maximal recordable radial SAP, consistent with an "abnormal radial normal sural" pattern. Somatosensory evoked potentials were unrecordable for tibial and median nerves. Cerebrospinal fluid protein was raised (0.99 g/L). The patient worsened on oral corticosteroids but subsequently made substantial functional recovery on intravenous immunoglobulins. This case is different to those previously reported of sensory chronic inflammatory demyelinating polyradiculoneuropathy, given its exclusive sensory electrophysiologic presentation, presence of predominant upper limb reduced sensory amplitudes, and detection of sensory conduction blocks. These electrophysiologic features were of paramount importance in establishing diagnosis and effective therapy.

Transcriptomic analysis on the formation of the viable putative non-culturable state of beer-spoilage Lactobacillus acetotolerans

PubMed Central

Liu, Junyan; Deng, Yang; Peters, Brian M.; Li, Lin; Li, Bing; Chen, Lequn; Xu, Zhenbo; Shirtliff, Mark E.

2016-01-01

Lactic acid bacteria (LAB) are the most common beer-spoilage bacteria regardless of beer type, and thus pose significant problems for the brewery industry. The aim of this study was to investigate the genetic mechanisms involved in the ability of the hard-to-culture beer-spoilage bacterium Lactobacillus acetotolerans to enter into the viable putative non-culturable (VPNC) state. A genome-wide transcriptional analysis of beer-spoilage L. acetotolerans strains BM-LA14526, BM-LA14527, and BM-LA14528 under normal, mid-term and VPNC states were performed using RNA-sequencing (RNA-seq) and further bioinformatics analyses. GO function, COG category, and KEGG pathway enrichment analysis were conducted to investigate functional and related metabolic pathways of the differentially expressed genes. Functional and pathway enrichment analysis indicated that heightened stress response and reduction in genes associated with transport, metabolic process, and enzyme activity might play important roles in the formation of the VPNC state. This is the first transcriptomic analysis on the formation of the VPNC state of beer spoilage L. acetotolerans. PMID:27819317

Transcriptomic analysis on the formation of the viable putative non-culturable state of beer-spoilage Lactobacillus acetotolerans.

PubMed

Liu, Junyan; Deng, Yang; Peters, Brian M; Li, Lin; Li, Bing; Chen, Lequn; Xu, Zhenbo; Shirtliff, Mark E

2016-11-07

Lactic acid bacteria (LAB) are the most common beer-spoilage bacteria regardless of beer type, and thus pose significant problems for the brewery industry. The aim of this study was to investigate the genetic mechanisms involved in the ability of the hard-to-culture beer-spoilage bacterium Lactobacillus acetotolerans to enter into the viable putative non-culturable (VPNC) state. A genome-wide transcriptional analysis of beer-spoilage L. acetotolerans strains BM-LA14526, BM-LA14527, and BM-LA14528 under normal, mid-term and VPNC states were performed using RNA-sequencing (RNA-seq) and further bioinformatics analyses. GO function, COG category, and KEGG pathway enrichment analysis were conducted to investigate functional and related metabolic pathways of the differentially expressed genes. Functional and pathway enrichment analysis indicated that heightened stress response and reduction in genes associated with transport, metabolic process, and enzyme activity might play important roles in the formation of the VPNC state. This is the first transcriptomic analysis on the formation of the VPNC state of beer spoilage L. acetotolerans.

Understanding ion association states and molecular dynamics using infrared spectroscopy

NASA Astrophysics Data System (ADS)

Masser, Hanqing

A molecular level understanding of the ion transport mechanism within polymer electrolytes is crucial to the further development for advanced energy storage applications. This can be achieved by the identification and quantitative measurement of different ion species in the system and further relating them to the ion conductivity. In the first part of this thesis, research is presented towards understanding the ion association states (free ions, ion pairs and ion aggregates) in ionomer systems, and the correlation of ion association states, ion conduction, polymer dynamics, and morphology. Ion conductivity in ionomers can be improved by lowering glass transition temperature, increasing polymer ion solvation ability, and adjusting ionomer structural variables such as ion content, cation type and side chain structure. These effects are studied in three ionomer systems respectively, using a combination of characterization methods. Fourier Transform Infrared Spectroscopy (FTIR) identifies and quantifies the ion association states. Dielectric Spectroscopy (DRS) characterizes ion conductivity and polymer and ion dynamics. X-ray scattering reveals changes in morphology. The influence of a cation solvating plasticizer on a polyester ionomer is systematically investigated with respect to ion association states, ion and polymer dynamics and morphology. A decrease in the number ratio of ion aggregates with increased plasticizer content and a slight increase at elevated temperature are observed in FTIR. Similar results are also detected by X-ray scattering. As determined from dielectric spectroscopy, ion conductivity increases with plasticizer content, in accordance with the decrease in glass transition temperature. Research on copolymer of poly(ethylene oxide) (PEO) and poly(tetramethylene oxide) (PTMO) based ionomers further develops an understanding of the trade-off between ion solvation and segmental dynamics. Upon the incorporation of PTMO, the majority of the PTMO microphase separates from the PEO-rich microphase, and ionic groups are preferentially solvated by PEO chains and reside in the PEO-rich microphase. As the ratio of PTMO increases, the fraction of aggregates increases, resulting in more highly coordinated aggregation states. Results on ion association states are in good agreement with previous results on ion conductivity, polymer dynamics and morphology. The effects of ion content, cation type and ionic side chain structure on ion association states are systemically studied in a series of ionomers with short ethylene oxide and ionic sulfonated styrene side chains, and then correlated to the ion and polymer dynamic characterization. It is found that ionomers with modest ion content, large cation and styrene ionic side chain have the most "free ions" and ion pairs, and highest ion conductivity. Ion conduction in ionomers is optimized by systematically changing their chemical structures. In addition to knowledge of ion association states, a IR band shape also contains information on molecular dynamics. In companion investigation, the vibrational relaxation and dynamic transitions of conformationally insensitive normal modes in two different polymer systems (atactic polystyrene and deuterated poly(methyl methacrylate)) are studied. The information on vibrational relaxations is resolved by conducting precisely controlled FTIR experiments, applying specialized curve resolving data analysis, and calculating time correlation functions through numerical Fourier transformation. The vibrational relaxations of these modes can be described by a two process model: a fast process on the time scale of 0.01 ps, which is inhomogeneously broadened by a slow process on the time scale of picoseconds.

Information cascade on networks

NASA Astrophysics Data System (ADS)

Hisakado, Masato; Mori, Shintaro

2016-05-01

In this paper, we discuss a voting model by considering three different kinds of networks: a random graph, the Barabási-Albert (BA) model, and a fitness model. A voting model represents the way in which public perceptions are conveyed to voters. Our voting model is constructed by using two types of voters-herders and independents-and two candidates. Independents conduct voting based on their fundamental values; on the other hand, herders base their voting on the number of previous votes. Hence, herders vote for the majority candidates and obtain information relating to previous votes from their networks. We discuss the difference between the phases on which the networks depend. Two kinds of phase transitions, an information cascade transition and a super-normal transition, were identified. The first of these is a transition between a state in which most voters make the correct choices and a state in which most of them are wrong. The second is a transition of convergence speed. The information cascade transition prevails when herder effects are stronger than the super-normal transition. In the BA and fitness models, the critical point of the information cascade transition is the same as that of the random network model. However, the critical point of the super-normal transition disappears when these two models are used. In conclusion, the influence of networks is shown to only affect the convergence speed and not the information cascade transition. We are therefore able to conclude that the influence of hubs on voters' perceptions is limited.

Reference Levels for Patient Radiation Doses in Interventional Radiology: Proposed Initial Values for U.S. Practice1

PubMed Central

Miller, Donald L.; Kwon, Deukwoo; Bonavia, Grant H.

2009-01-01

Purpose: To propose initial values for patient reference levels for fluoroscopically guided procedures in the United States. Materials and Methods: This secondary analysis of data from the Radiation Doses in Interventional Radiology Procedures (RAD-IR) study was conducted under a protocol approved by the institutional review board and was HIPAA compliant. Dose distributions (percentiles) were calculated for each type of procedure in the RAD-IR study where there were data from at least 30 cases. Confidence intervals for the dose distributions were determined by using bootstrap resampling. Weight banding and size correction methods for normalizing dose to patient body habitus were tested. Results: The different methods for normalizing patient radiation dose according to patient weight gave results that were not significantly different (P > .05). The 75th percentile patient radiation doses normalized with weight banding were not significantly different from those that were uncorrected for body habitus. Proposed initial reference levels for various interventional procedures are provided for reference air kerma, kerma-area product, fluoroscopy time, and number of images. Conclusion: Sufficient data exist to permit an initial proposal of values for reference levels for interventional radiologic procedures in the United States. For ease of use, reference levels without correction for body habitus are recommended. A national registry of radiation-dose data for interventional radiologic procedures is a necessary next step to refine these reference levels. © RSNA, 2009 Supplemental material: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.2533090354/-/DC1 PMID:19789226

Karyometry detects subvisual differences in chromatin organization state between cribriform and flat high-grade prostatic intraepithelial neoplasia.

PubMed

Montironi, Rodolfo; Thompson, Deborah; Scarpelli, Marina; Mazzucchelli, Roberta; Peketi, Prasanthi; Hamilton, Peter W; Bostwick, David G; Bartels, Peter H

2004-08-01

This digital texture analysis-based study evaluates the chromatin organization state in flat and cribriform high-grade prostatic intraepithelial neoplasia (PIN), in the adjacent normal looking secretory epithelium and in the co-occurring adenocarcinoma. Digital texture analysis (karyometry) was carried out on hematoxylin and eosin-stained sections from 24 radical prostatectomy specimens with high-grade PIN (12 with flat and 12 with cribriform architectural pattern, respectively) and cancer. Quantification was also conducted on the normal looking secretory epithelium. Discriminant analysis and the nonsupervised learning algorithm P-index were used to identify suitable subsets of features useful for the discrimination and classification of pathological groups and to explore multivariate data structure in the pathological subgroups. The average nuclear abnormality increases monotonically from the histologically normal appearing secretory epithelium to high-grade PIN and to adenocarcinoma. The nuclei from the so-called perimeter compartment of the flat high-grade PIN lesions show a higher nuclear abnormality compared to the nuclei of the cribriform high-grade PINs. Discriminant analysis shows that flat and cribriform high-grade PINs fall into two populations. Processing by the nonsupervised learning algorithm P-index revealed the existence of three well-defined, distinct subpopulations of nuclei of different chromatin phenotype. In the flat high-grade PIN lesions the proportions of nuclei in the three subpopulations are 16.5% (low abnormality), 25.0% (mid abnormality) and 58.5% (high abnormality), respectively. In the cribriform high-grade PIN lesions, 100% of the nuclei are in the mid-abnormality subpopulation. These differences are also discernible in the co-occurring adenocarcinoma and the histologically normal appearing secretory epithelium. To conclude, karyometry and statistical analysis detect the existence of distinct cell subpopulations of different chromatin packaging and phenotype, with the nuclei from the flat high-grade PIN lesions, adjacent normal looking epithelium and co-occurring adenocarcinoma expressing a greater nuclear abnormality than in the specimens with cribriform high-grade PIN.

Vortices and gate-tunable bound states in a topological insulator coupled to superconducting leads

NASA Astrophysics Data System (ADS)

Finck, Aaron; Kurter, C.; Hor, Y. S.; van Harlingen, D. J.

2014-03-01

It has been predicted that zero energy Majorana bound states can be found in the core of vortices within topological superconductors. Here, we report on Andreev spectroscopy measurements of the topological insulator Bi2Se3 with a normal metal lead and one or more niobium leads. The niobium induces superconductivity in the Bi2Se3 through the proximity effect, leading to both signatures of Andreev reflection and a prominent re-entrant resistance effect. When a large magnetic field is applied perpendicular to the surface of the Bi2Se3, we observe multiple abrupt changes in the subgap conductance that are accompanied by sharp peaks in the dynamical resistance. These peaks are very sensitive to changes in magnetic field and disappear at temperatures associated with the critical temperature of the induced superconductivity. The appearance of the transitions and peaks can be tuned by a top gate. At high magnetic fields, we also find evidence of gate-tunable states, which can lead to stable zero-bias conductance peaks. We interpret our results in terms of a transition occurring within the proximity effect region of the topological insulator, likely due to the formation of vortices. We acknowledge support from Microsoft Project Q.

Apparent Dependence of Rate- and State-Dependent Friction Parameters on Loading Velocity and Cumulative Displacement Inferred from Large-Scale Biaxial Friction Experiments

NASA Astrophysics Data System (ADS)

Urata, Yumi; Yamashita, Futoshi; Fukuyama, Eiichi; Noda, Hiroyuki; Mizoguchi, Kazuo

2017-06-01

We investigated the constitutive parameters in the rate- and state-dependent friction (RSF) law by conducting numerical simulations, using the friction data from large-scale biaxial rock friction experiments for Indian metagabbro. The sliding surface area was 1.5 m long and 0.5 m wide, slid for 400 s under a normal stress of 1.33 MPa at a loading velocity of either 0.1 or 1.0 mm/s. During the experiments, many stick-slips were observed and those features were as follows. (1) The friction drop and recurrence time of the stick-slip events increased with cumulative slip displacement in an experiment before which the gouges on the surface were removed, but they became almost constant throughout an experiment conducted after several experiments without gouge removal. (2) The friction drop was larger and the recurrence time was shorter in the experiments with faster loading velocity. We applied a one-degree-of-freedom spring-slider model with mass to estimate the RSF parameters by fitting the stick-slip intervals and slip-weakening curves measured based on spring force and acceleration of the specimens. We developed an efficient algorithm for the numerical time integration, and we conducted forward modeling for evolution parameters ( b) and the state-evolution distances (L_{{c}}), keeping the direct effect parameter ( a) constant. We then identified the confident range of b and L_{{c}} values. Comparison between the results of the experiments and our simulations suggests that both b and L_{{c}} increase as the cumulative slip displacement increases, and b increases and L_{{c}} decreases as the loading velocity increases. Conventional RSF laws could not explain the large-scale friction data, and more complex state evolution laws are needed.

Auditory brainstem responses of CBA/J mice with neonatal conductive hearing losses and treatment with GM1 ganglioside.

PubMed

Money, M K; Pippin, G W; Weaver, K E; Kirsch, J P; Webster, D B

1995-07-01

Exogenous administration of GM1 ganglioside to CBA/J mice with a neonatal conductive hearing loss ameliorates the atrophy of spiral ganglion neurons, ventral cochlear nucleus neurons, and ventral cochlear nucleus volume. The present investigation demonstrates the extent of a conductive loss caused by atresia and tests the hypothesis that GM1 ganglioside treatment will ameliorate the conductive hearing loss. Auditory brainstem responses were recorded from four groups of seven mice each: two groups received daily subcutaneous injections of saline (one group had normal hearing; the other had a conductive hearing loss); the other two groups received daily subcutaneous injections of GM1 ganglioside (one group had normal hearing; the other had a conductive hearing loss). In mice with a conductive loss, decreases in hearing sensitivity were greatest at high frequencies. The decreases were determined by comparing mean ABR thresholds of the conductive loss mice with those of normal hearing mice. The conductive hearing loss induced in the mice in this study was similar to that seen in humans with congenital aural atresias. GM1 ganglioside treatment had no significant effect on ABR wave I thresholds or latencies in either group.

Prediction of terrestrial gamma dose rate based on geological formations and soil types in the Johor State, Malaysia.

PubMed

Saleh, Muneer Aziz; Ramli, Ahmad Termizi; bin Hamzah, Khaidzir; Alajerami, Yasser; Moharib, Mohammed; Saeed, Ismael

2015-10-01

This study aims to predict and estimate unmeasured terrestrial gamma dose rate (TGDR) using statistical analysis methods to derive a model from the actual measurement based on geological formation and soil type. The measurements of TGDR were conducted in the state of Johor with a total of 3873 measured points which covered all geological formations, soil types and districts. The measurements were taken 1 m above the soil surface using NaI [Ti] detector. The measured gamma dose rates ranged from 9 nGy h(-1) to 1237 nGy h(-1) with a mean value of 151 nGy h(-1). The data have been normalized to fit a normal distribution. Tests of significance were conducted among all geological formations and soil types, using the unbalanced one way ANOVA. The results indicated strong significant differences due to the different geological formations and soil types present in Johor State. Pearson Correlation was used to measure the relations between gamma dose rate based on geological formation and soil type (D(G,S)) with the gamma dose rate based on geological formation (D(G)) or soil type (D(s)). A very good correlation was found between D(G,S) and D(G) or D(G,S) and D(s). A total of 118 pairs of geological formations and soil types were used to derive the statistical contribution of geological formations and soil types to gamma dose rates. The contribution of the gamma dose rate from geological formation and soil type were found to be 0.594 and 0.399, respectively. The null hypotheses were accepted for 83% of examined data, therefore, the model could be used to predict gamma dose rates based on geological formation and soil type information. Copyright © 2015 Elsevier Ltd. All rights reserved.

Inhalation Injury: Pathophysiology and Clinical Care. Proceedings of a Symposium Conducted at the Trauma Institute of San Antonio, San Antonio, TX, USA on 28 March 2006

DTIC Science & Technology

2007-01-01

the Hounsfield - unit ranges established by Gattinoni et al. [23] (air: hyperinflated, normal, poorly aerated, and non-aerated lung). The fraction of...T. J., Wolf S. E., 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) United States Army...Abnormally low V/Q is ɘ.1 and abnormally high is V/Q > 10. Shunt is specified as blood flow in units with V/Q < 0.005 and dead space as ventilation

Pore pressure diffusion and the hydrologic response of nearly saturated, thin landslide deposits of rainfall

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

Haneberg, W.C.

1991-11-01

Previous workers have correlated slope failures during rainstorms with rainfall intensity, rainfall duration, and seasonal antecedent rainfall. This note shows how such relationships can be interpreted using a periodic steady-state solution to the well-known linear pressure diffusion equation. Normalization of the governing equation yields a characteristic response time that is a function of soil thickness, saturated hydraulic conductivity, and pre-storm effective porosity, and which is analogous to the travel time of a piston wetting front. The effects of storm frequency and magnitude are also successfully quantified using dimensionless attenuation factors and lag times.

State of the mineral component of rat bone tissue during hypokinesia and the recovery period

NASA Technical Reports Server (NTRS)

Volozhin, A. I.; Stupakov, G. P.; Pavlova, M. N.; Muradov, I. S.

1980-01-01

Experiments were conducted on young growing rats. Hypokinesia lasting from 20 to 200 days caused retarded gain in weight and volume of the femur and delayed development of the cortical layer of the diaphysis. In contrast, the density of the cortical layer of the femoral diaphysis increased due to elevation of the mineral saturation of the bone tissue microstructures. Incorporation of Ca into the bone tissue in hypokinesia had a tendency to reduce. Partial normalization of the bone tissue mineral component occurred during a 20 day recovery period following hypokinesia.

Thermophysical properties of Helium-4 from 0.8 to 1500 K with pressures to 2000 MPa

NASA Technical Reports Server (NTRS)

Arp, Vincent D.; Mccarty, Robert D.

1989-01-01

Tabular summary data of the thermophysical properties of fluid helium are given for temperatures from 0.8 to 1500 K, with pressures to 2000 MPa between 75 and 300 K, or to 100 MPa outside of this temperature band. Properties include density, specific heats, enthalpy, entropy, internal energy, sound velocity, expansivity, compressibility, thermal conductivity, and viscosity. The data are calculated from a computer program which is available from the National Institute of Standards and Technology. The computer program is based on carefully fitted state equations for both normal and superfluid helium.

Conductance of graphene based normal-superconductor junction with double magnetic barriers

NASA Astrophysics Data System (ADS)

Abdollahipour, B.; Mohebalipour, A.; Maleki, M. A.

2018-05-01

We study conductance of a graphene based normal metal-superconductor junction with two magnetic barriers. The magnetic barriers are induced via two applied magnetic fields with the same magnitudes and opposite directions accompanied by an applied electrostatic potential. We solve Dirac-Bogoliubov-De-Gennes (DBdG) equation to calculate conductance of the junction. We find that applying the magnetic field leads to suppression of the Andreev reflection and conductance for all energies. On the other hand, we observe a crossover from oscillatory to tunneling behavior of the conductance as a function of the applied potential by increasing the magnetic field.

Pseudogap and conduction dimensionalities in high-Tc superconductors

NASA Astrophysics Data System (ADS)

Das Arulsamy, Andrew; Ong, P. C.; Ong, M. T.

2003-01-01

The nature of normal state charge-carriers' dynamics and the transition in conduction and gap dimensionalities between 2D and 3D for YBa2Cu3O7-δ and Bi2Sr2Ca1- xYxCu2O8 high-Tc superconductors were described by computing and fitting the resistivity curves, /ρ(T,δ,x). These were carried out by utilizing the 2D and 3D Fermi liquid and ionization energy (EI) based resistivity models coupled with charge-spin separation based /t-/J model (Phys. Rev. B 64 (2001) 104516). /ρ(T,δ,x) curves of Y123 and Bi2212 samples indicate the beginning of the transition of conduction and gap from 2D to 3D with reduction in oxygen content /(7-δ) and Ca2+(1-x) as such, /c-axis pseudogap could be a different phenomenon from superconductor and spin gaps. These models also indicate that the recent MgB2 superconductor is at least not Y123 or Bi2212 type.

Transport spectroscopy of induced superconductivity in the three-dimensional topological insulator HgTe

NASA Astrophysics Data System (ADS)

Wiedenmann, Jonas; Liebhaber, Eva; Kübert, Johannes; Bocquillon, Erwann; Burset, Pablo; Ames, Christopher; Buhmann, Hartmut; Klapwijk, Teun M.; Molenkamp, Laurens W.

2017-10-01

The proximity-induced superconducting state in the three-dimensional topological insulator HgTe has been studied using electronic transport of a normal metal-superconducting point contact as a spectroscopic tool (Andreev point-contact spectroscopy). By analyzing the conductance as a function of voltage for various temperatures, magnetic fields, and gate voltages, we find evidence, in equilibrium, for an induced order parameter in HgTe of 70 µeV and a niobium order parameter of 1.1 meV. To understand the full conductance curve as a function of applied voltage we suggest a non-equilibrium-driven transformation of the quantum transport process where the relevant scattering region and equilibrium reservoirs change with voltage. This change implies that the spectroscopy probes the superconducting correlations at different positions in the sample, depending on the bias voltage.

Advancement of proprotor technology. Task 1: Design study summary. [aerodynamic concept of minimum size tilt proprotor research aircraft

NASA Technical Reports Server (NTRS)

1969-01-01

A tilt-proprotor proof-of-concept aircraft design study has been conducted. The results are presented. The ojective of the contract is to advance the state of proprotor technology through design studies and full-scale wind-tunnel tests. The specific objective is to conduct preliminary design studies to define a minimum-size tilt-proprotor research aircraft that can perform proof-of-concept flight research. The aircraft that results from these studies is a twin-engine, high-wing aircraft with 25-foot, three-bladed tilt proprotors mounted on pylons at the wingtips. Each pylon houses a Pratt and Whitney PT6C-40 engine with a takeoff rating of 1150 horsepower. Empty weight is estimated at 6876 pounds. The normal gross weight is 9500 pounds, and the maximum gross weight is 12,400 pounds.

Aggressive and Prosocial Behaviors before and after Treatment in Conduct-Disordered Children and in Matched Controls.

ERIC Educational Resources Information Center

Konstantareas, M. Mary; Homatidis, Soula

1984-01-01

Examines groups of conduct-disordered and normal children in order to (1) test the potential usefulness of observational techniques in assessing therapeutic outcomes and (2) identify possible differences between deviant children and normal peers in aggressive and prosocial behavior. (RH)

Clinical investigations of the therapeutic potential of ayahuasca: rationale and regulatory challenges.

PubMed

McKenna, Dennis J

2004-05-01

Ayahuasca is a hallucinogenic beverage that is prominent in the ethnomedicine and shamanism of indigenous Amazonian tribes. Its unique pharmacology depends on the oral activity of the hallucinogen, N,N-dimethyltryptamine (DMT), which results from inhibition of monoamine oxidase (MAO) by beta-carboline alkaloids. MAO is the enzyme that normally degrades DMT in the liver and gut. Ayahuasca has long been integrated into mestizo folk medicine in the northwest Amazon. In Brazil, it is used as a sacrament by several syncretic churches. Some of these organizations have incorporated in the United States. The recreational and religious use of ayahuasca in the United States, as well as "ayahuasca tourism" in the Amazon, is increasing. The current legal status of ayahuasca or its source plants in the United States is unclear, although DMT is a Schedule I controlled substance. One ayahuasca church has received favorable rulings in 2 federal courts in response to its petition to the Department of Justice for the right to use ayahuasca under the Religious Freedom Restoration Act. A biomedical study of one of the churches, the Uñiao do Vegetal (UDV), indicated that ayahuasca may have therapeutic applications for the treatment of alcoholism, substance abuse, and possibly other disorders. Clinical studies conducted in Spain have demonstrated that ayahuasca can be used safely in normal healthy adults, but have done little to clarify its potential therapeutic uses. Because of ayahuasca's ill-defined legal status and variable botanical and chemical composition, clinical investigations in the United States, ideally under an approved Investigational New Drug (IND) protocol, are complicated by both regulatory and methodological issues. This article provides an overview of ayahuasca and discusses some of the challenges that must be overcome before it can be clinically investigated in the United States.

Recent advances of high voltage AlGaN/GaN power HFETs

NASA Astrophysics Data System (ADS)

Uemoto, Yasuhiro; Ueda, Tetsuzo; Tanaka, Tsuyoshi; Ueda, Daisuke

2009-02-01

We review our recent advances of GaN-based high voltage power transistors. These are promising owing to low on-state resistance and high breakdown voltage taking advantages of superior material properties. However, there still remain a couple of technical issues to be solved for the GaN devices to replace the existing Si-based power devices. The most critical issue is to achieve normally-off operation which is strongly desired for the safety operation, however, it has been very difficult because of the built-in polarization electric field. Our new device called GIT (Gate Injection Transistor) utilizing conductivity modulation successfully achieves the normally-off operation keeping low on-state resistance. The fabricated GIT on a Si substrate exhibits threshold voltage of +1.0V. The obtained on-state resistance and off-state breakdown voltage were 2.6mΩ•cm2 and 800V, respectively. Remaining technical issue is to further increase the breakdown voltage. So far, the reported highest off-state breakdown voltage of AlGaN/GaN HFETs has been 1900V. Overcoming these issues by a novel device structure, we have demonstrated the world highest breakdown voltages of 10400V using thick poly-crystalline AlN as a passivation film and Via-holes through sapphire which enable very efficient layout of the lateral HFET array avoiding any undesired breakdown of passivation films. Since conventional wet or dry etching cannot be used for chemically stable sapphire, high power pulsed laser is used to form the via-holes. The presented GaN power devices demonstrate that GaN is advantageous for high voltage power switching applications replacing currently used Si-based power MOSFETs and IGBTs.

Comparisons between gouge and bare surface friction of serpentinite at seismic slip velocities: Implications for dynamic weakening of gouge-bearing faults

NASA Astrophysics Data System (ADS)

Proctor, B.; Mitchell, T. M.; Hirth, G.; Goldsby, D. L.; Di Toro, G.; Zorzi, F.

2013-12-01

High-velocity friction (HVF) experiments on bare rock surfaces have revealed various dynamic weakening processes (e.g., flash weakening, gel weakening, melt lubrication) that likely play a fundamental role in coseismic fault weakening. However, faults generally contain a thin layer of gouge separating the solid wallrocks, thus it is important to understand how the presence of gouge modifies the efficiency of these weakening processes at seismic slip rates. We explored the frictional behavior of bare surfaces and powdered samples of an antigorite-rich serpentinite (ARS) and a lizardite-rich serpentinite (LRS) at earthquake slip rates. HVF experiments were conducted with slip displacements ranging from ~0.5 to 2m, at velocities ranging from 0.002m/s to 6.5 m/s, and with normal stresses ranging from 2-22 MPa for gouge and 5-100MPa for bare surfaces. Our results demonstrate that the friction coefficient (μ) of powdered serpentine is significantly larger than that of bare surfaces under otherwise identical conditions. Bare surface friction decreases over a weakening distance of a few centimeters to a nominally steady-state value of ~0.1 at velocities greater than 0.1m/s. The nominal steady-state friction decreases non-linearly with increasing normal stress from 0.14 to 0.045 at 5 and ~100MPa respectfully at a slip velocity of 1m/s. Additionally, the recovery of frictional strength during deceleration depends on total displacement; samples slipped for ~50mm recover faster than samples slipped for ~0.5m. Microstructural analysis of bare surfaces deformed at the highest normal stresses revealed translucent glass-like material on the slip surfaces and XRD analysis of wear material revealed an increasing presence of olivine and enstatite with increasing normal stress. In contrast, gouge requires an order of magnitude higher velocity than bare surfaces to induce frictional weakening, has a larger weakening distance and higher steady state friction values for equivalent deformation conditions. Furthermore, we observe a strong normal stress dependence of the nominal steady state friction and the weakening distance of ARS and LRS gouge from 0.51 to 0.39 and from 25-10cm at 4MPa and 22MPa, respectfully, for at a slip velocity of 1m/s. Strain was localized onto a shear surface in the range of 100-300 microns wide in all gouge samples deformed at >10cm/s and XRD analyses revealed the presence of olivine and enstatite in samples with the most weakening and none in samples with no weakening. Our results indicate that dynamic weakening occurs in gouge at low normal stress in response to strain localization and shear heating of the slip surface. However, because more initial displacement is required to localize strain, weakening initiates at higher velocities and after larger weakening distances than bare surfaces. At higher normal stress, localization occurs after less displacement and the differences between gouge and bare-surface friction diminish; extrapolation of our data suggests that the behavior of serpentine gouge will approach that of bare surfaces at normal stresses ≥60 MPa.

Magnetic measurements on human erythrocytes: Normal, beta thalassemia major, and sickle

NASA Astrophysics Data System (ADS)

Sakhnini, Lama

2003-05-01

In this article magnetic measurements were made on human erythrocytes at different hemoglobin states (normal and reduced hemoglobin). Different blood samples: normal, beta thalassemia major, and sickle were studied. Beta thalassemia major and sickle samples were taken from patients receiving lifelong blood transfusion treatment. All samples examined exhibited diamagnetic behavior. Beta thalassemia major and sickle samples showed higher diamagnetic susceptibilities than that for the normal, which was attributed to the increase of membrane to hemoglobin volume ratio of the abnormal cells. Magnetic measurements showed that the erythrocytes in the reduced state showed less diamagnetic response in comparison with erythrocytes in the normal state. Analysis of the paramagnetic component of magnetization curves gave an effective magnetic moment of μeff=7.6 μB per reduced hemoglobin molecule. The same procedure was applied to sickle and beta thalassemia major samples and values for μeff were found to be comparable to that of the normal erythrocytes.

A moving target: responding to magnetic and structural disorder in lanthanide- and actinide-based superconductors

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

Bauer, Eric D; Mitchell, Jeremy N; Booth, C H

2009-01-01

The effects of various chemical substitutions and induced lattice disorder in the Ce- and Pu-based 115 superconductors are reviewed, with particular emphasis on results from x-ray absorption fine structure (XAFS) measurements. The competition between spin, charge, and lattice interactions is at the heart of many of the strongly-correlated ground states in materials of current interest, such as in colossal magnetoresistors and high-temperature superconductors. This relationship is particularly strong in the CeTIn{sub 5} and PuTGa{sub 5} series (T = Co, Rh, Ir) of heavy-fermion superconductors. In these systems (figure 1), competition between bulk magnetic and non-magnetic ground states, as well asmore » between superconducting and normal states, are directly related to local properties around the lanthanide or actinide ion, such as the nearest-neighbor bond lengths and the local density of states at the Fermi level. Tiny changes in the latter values can easily tip the balance from one ground state to another. This paper reviews recent work by the authors exploring the relationship between local crystal and electronic structure and ground state magnetic and conducting properties in the Ce- and Pu-based 115 materials.« less

Liquid jet impingement normal to a disk in zero gravity. Ph.D. Thesis - Toledo Univ.

NASA Technical Reports Server (NTRS)

Labus, T. L.

1976-01-01

An experimental and analytical investigation was conducted to determine the free surface shapes of circular liquid jets impinging normal to sharp-edged disks under both normal and zero gravity conditions. An order of magnitude analysis was conducted indicating regions where viscous forces were not significant when computing free surface shapes. The demarcation between the viscous and inviscid region was found to depend upon the flow Reynolds number and the ratio between the jet and disk radius.

Characteristics of Asperity Damage and Its Influence on the Shear Behavior of Granite Joints

NASA Astrophysics Data System (ADS)

Meng, Fanzhen; Zhou, Hui; Wang, Zaiquan; Zhang, Chuanqing; Li, Shaojun; Zhang, Liming; Kong, Liang

2018-02-01

Surface roughness significantly affects the shear behavior of rock joints; thus, studies on the asperity damage characteristics and its influence on the shear behavior of joints are extremely important. In this paper, shear tests were conducted on tensile granite joints; asperity damage was evaluated based on acoustic emission (AE) events; and the influence of asperity damage on joint shear behavior was analyzed. The results indicated that the total AE events tended to increase with normal stress. In addition, the asperity damage initiation shear stress, which is defined as the transition point from slow growth to rapid growth in the cumulative events curve, was approximately 0.485 of the peak shear strength regardless of the normal stress. Moreover, 63-85% of the AE events were generated after the peak shear stress, indicating that most of the damage occurred in this stage. Both the dilation and the total AE events decreased with shear cycles because of the damage inflicted on asperities during the previous shear cycle. Two stages were observed in the normal displacement curves under low normal stress, whereas three stages (compression, dilation and compression again) were observed at a higher normal stress; the second compression stage may be caused by tensile failure outside the shear plane. The magnitude of the normal stress and the state of asperity are two important factors controlling the post-peak stress drop and stick-slip of granite joints. Serious deterioration of asperities will stop stick-slip from recurring under the same normal stress because the ability to accumulate energy is decreased. The AE b-value increases with the number of shear cycles, indicating that the stress concentration inside the fault plane is reduced because of asperity damage; thus, the potential for dynamic disasters, such as fault-slip rockbursts, will be decreased.

Accurate determination of complex materials coefficients of piezoelectric resonators.

PubMed

Du, Xiao-Hong; Wang, Qing-Ming; Uchino, Kenji

2003-03-01

This paper presents a method of accurately determining the complex piezoelectric and elastic coefficients of piezoelectric ceramic resonators from the measurement of the normalized electric admittance, Y, which is electric admittance Y of piezoelectric resonator normalized by the angular frequency omega. The coefficients are derived from the measurements near three special frequency points that correspond to the maximum and the minimum normalized susceptance (B) and the maximum normalized conductance (G). The complex elastic coefficient is determined from the frequencies at these points, and the real and imaginary parts of the piezoelectric coefficient are related to the derivative of the susceptance with respect to the frequency and the asymmetry of the conductance, respectively, near the maximum conductance point. The measurements for some lead zirconate titanate (PZT) based ceramics are used as examples to demonstrate the calculation and experimental procedures and the comparisons with the standard methods.

Validated Numerical Models for the Convective Extinction of Fuel Droplets (CEFD)

NASA Technical Reports Server (NTRS)

Gogos, George; Bowen, Brent; Nickerson, Jocelyn S.

2002-01-01

The NASA Nebraska Space Grant (NSGC) & EPSCoR programs have continued their effort to support outstanding research endeavors by funding the Numerical Simulation of the Combustion of Fuel Droplets study at the University of Nebraska at Lincoln (UNL). This team of researchers has developed a transient numerical model to study the combustion of suspended and moving droplets. The engines that propel missiles, jets, and many other devices are dependent upon combustion. Therefore, data concerning the combustion of fuel droplets is of immediate relevance to aviation and aeronautical personnel, especially those involved in flight operations. The experiments being conducted by Dr. Gogos and Dr. Nayagam s research teams, allow investigators to gather data for comparison with theoretical predictions of burning rates, flame structures, and extinction conditions. The consequent improved fundamental understanding of droplet combustion may contribute to the clean and safe utilization of fossil fuels (Williams, Dryer, Haggard & Nayagam, 1997, f 2). The present state of knowledge on convective extinction of fuel droplets derives from experiments conducted under normal gravity conditions. However, any data obtained with suspended droplets under normal gravity are grossly affected by gravity. The need to obtain experimental data under microgravity conditions is therefore well justified and addresses one of the goals of NASA's Human Exploration and Development of Space (HEDS) microgravity combustion experiment.

Direct measurement of asperity contact growth in quartz at hydrothermal conditions

USGS Publications Warehouse

Beeler, Nicholas M.; Hickman, Stephen H.

2015-01-01

Earthquake recurrence requires interseismic fault restrengthening which results from solid state deformation in room-temperature friction and indentation experiments. In contrast exhumed fault zones show solution-transport processes such as pressure solution and contact overgrowths influence fault zone properties . In the absence of fluid flow, overgrowths are driven by gradients in surface curvature where material is dissolved, diffuses, and precipitates at the contact without convergence normal to the contact. To determine the rate of overgrowth for quartz, we conducted single contact experiments in an externally heated pressure vessel. Convergence was continuously monitored using reflected-light interferometry through a long-working-distance microscope. Contact normal force was constant with an initial effective normal stress of 1.7 MPa, temperature was between 350 and 530{degree sign}C, and water pressure was constant at 150 MPa. Two control experiments were conducted: one dry at 425{degree sign}C and one bi-material (sapphire) at 425{degree sign}C and 150 MPa water pressure. No contact growth or convergence was observed in the controls. For wet single-phase contacts, growth was initially rapid and then decreased with time. No convergence was observed. Fluid inclusions indicate that the contact is not uniformly wetted. The contact is bounded by small regions of high aperture, reflecting local free-face dissolution as the source for the overgrowth. The apparent activation energy is ~125 kJ/mol. Extrapolation predicts rates of contact area increase orders of magnitude faster than in dry, room-temperature and hydrothermal friction experiments, suggesting that natural strength recovery near the base of the seismogenic zone could be dominated by contact overgrowth.

Thermal boundary resistance between sapphire and aluminum monocrystals at low temperature

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

Sahling, S.; Engert, J.; Gladun, A.

1981-12-01

The thermal boundary resistance at boundaries between monocrystalline sapphire and monocrystalline aluminum and between monocrystalline sapphire and polycrystalline aluminum has been measured in the temperature range from 0.1 to 6 K with aluminum in the superconducting and normal states. The ratio of the thermal boundary resistance of the aluminum monocrystals in the superconducting state to that in the normal state increases as the temperature is lowered, reaches a maximum at about 0.13 K, and decreases at still lower temperatures. At the maximum, the thermal boundary resistance in the superconducting state is two orders of magnitude larger than the resistance inmore » the normal state.« less

The significance of nerve sugar levels for the peripheral nerve impairment of spontaneously diabetic GK (Goto-Kakizaki) rats.

PubMed

Suzuki, K; Yen-Chung, H; Toyota, T; Goto, Y; Hirata, Y; Okada, K

1990-05-01

This study was carried out to clarify the relationship between the slowing of motor nerve conduction velocity and nerve levels of sorbitol, fructose, glucose and myoinositol in spontaneously diabetic GK (Goto-Kakizaki) rats. The motor nerve conduction velocity in GK rats was constantly lower than in normal controls at three and nine months of age. This constant decrease in motor nerve conduction velocity in GK rats was closely related to glucose intolerance in GK rats soon after birth. Nerve levels of sorbitol, glucose and fructose in GK rats were significantly increased as compared to normal controls at nine months old, but not (except glucose) at three months old. The increase in nerve concentrations of sugars in GK rats was progressive with age. However, levels of glucose, sorbitol and fructose in normal Wistar rats remain unchanged with age. Although nerve myo-inositol levels in GK rats were lower at three and nine months than those of normal controls, a significant difference in myo-inositol levels was observed only at nine months. On the contrary, nerve myo-inositol level in normal Wistar rats did not show age-related change. These findings suggested that both enhanced polyol pathway activity and myo-inositol depletion play important roles in the reduction of motor nerve conduction velocity.

Exploring Science Teachers' Affective States: Pedagogical Discontentment, Self-efficacy, Intentions to Reform, and Their Relationships

NASA Astrophysics Data System (ADS)

Kahveci, Ajda; Kahveci, Murat; Mansour, Nasser; Alarfaj, Maher Mohammed

2017-06-01

Teachers play a key role in moving reform-based science education practices into the classroom. Based on research that emphasizes the importance of teachers' affective states, this study aimed to explore the constructs pedagogical discontentment, science teaching self-efficacy, intentions to reform, and their correlations. Also, it aimed to provide empirical evidence in light of a previously proposed theoretical model while focusing on an entirely new context in Middle East. Data were collected in Saudi Arabia with a total of randomly selected 994 science teachers, 656 of whom were females and 338 were males. To collect the data, the Arabic versions of the Science Teachers' Pedagogical Discontentment scale, the Science Teaching Efficacy Beliefs Instrument and the Intentions to Reform Science Teaching scale were developed. For assuring the validity of the instruments in a non-Western context, rigorous cross-cultural validations procedures were followed. Factor analyses were conducted for construct validation and descriptive statistical analyses were performed including frequency distributions and normality checks. Univariate analyses of variance were run to explore statistically significant differences between groups of teachers. Cross-tabulation and correlation analyses were conducted to explore relationships. The findings suggest effect of teacher characteristics such as age and professional development program attendance on the affective states. The results demonstrate that teachers who attended a relatively higher number of programs had lower level of intentions to reform raising issues regarding the conduct and outcomes of professional development. Some of the findings concerning interrelationships among the three constructs challenge and serve to expand the previously proposed theoretical model.

Infant botulism due to consumption of contaminated commercially prepared honey. First report from the Arabian Gulf States.

PubMed

van der Vorst, Maria M J; Jamal, Wafaa; Rotimi, Vincent O; Moosa, Alie

2006-01-01

To report the first case of infant botulism in Arabian Gulf States. A 6-week-old infant, presenting with signs of sepsis, was intubated and ventilated due to progressive weakness. Infant botulism was suspected with acute flaccid paralysis and a history of honey consumption. An electromyogram showed decreased amplitude of compound muscle action potential in all motor nerves, preserved sensory responses; the motor terminal latencies and motor conduction velocities were normal. Blood, stool and honey samples were sent for culture. Stool and honey cultures showed two identical strains of Clostridium botulinum. This case shows that the infant botulism occurred from the ingested contaminated honey. Hence vigilance should be maintained when a baby is fed honey and shows signs of progressive weakness because the disease can quickly progress to respiratory failure.

Metal-to-insulator crossover in YBa2Cu3Oy probed by low-temperature quasiparticle heat transport.

PubMed

Sun, X F; Segawa, Kouji; Ando, Yoichi

2004-09-03

It was recently demonstrated that in La2-xSrxCuO4 the magnetic-field (H) dependence of the low-temperature thermal conductivity kappa up to 16 T reflects whether the normal state under high magnetic field is a metal or an insulator. We measure the H dependence of kappa in YBa(2)Cu(3)O(y) (YBCO) at subkelvin temperatures for a wide doping range, and find that at low doping the kappa(H) behavior signifies the change in the ground state in this system as well. Surprisingly, the critical doping is found to be located deeply inside the underdoped region, about the hole doping of 0.07 hole/Cu; this critical doping is apparently related to the stripe correlations as revealed by the in-plane resistivity anisotropy.

Developments in new aircraft tire tread materials. [fatigue life of elastomeric materials

NASA Technical Reports Server (NTRS)

Yager, T. J.; Mccarty, J. L.; Riccitiello, S. R.; Golub, M. A.

1976-01-01

Comparative laboratory and field tests were conducted on experimental and state-of-the-art aircraft tire tread materials in a program aimed at seeking new elastomeric materials which would provide improved aircraft tire tread wear, traction, and blowout resistance in the interests of operational safety and economy. The experimental stock was formulated of natural rubber and amorphous vinyl polybutadiene to provide high thermal-oxidative resistance, a characteristic pursued on the premise that thermal oxidation is involved both in the normal abrasion or wear of tire treads and probably in the chain of events leading to blowout failures. Results from the tests demonstrate that the experimental stock provided better heat buildup (hysteresis) and fatigue properties, at least equal wet and dry traction, and greater wear resistance than the state-of-the-art stock.

Catheter ablation as a treatment of atrioventricular block.

PubMed

Tuohy, Stephen; Saliba, Walid; Pai, Manjunath; Tchou, Patrick

2018-01-01

Symptomatic second-degree atrioventricular (AV) block is typically treated by implantation of a pacemaker. An otherwise healthy AV conduction system can nevertheless develop AV block due to interference from junctional extrasystoles. When present with a high burden, these can produce debilitating symptoms from AV block despite an underlying normal AV node and His-Purkinje system properties. The purpose of this study was to describe a catheter ablation approach for alleviating symptomatic AV block due to a ventricular nodal pathway interfering with AV conduction. Common clinical monitoring techniques such as Holter and event recorders were used. Standard electrophysiological study techniques using multipolar recording and ablation catheters were utilized during procedures. A 55-year-old woman presented with highly symptomatic, high-burden second-degree AV block due to concealed and manifest junctional premature beats. Electrophysiological characteristics indicated interference of AV conduction due to a concealed ventricular nodal pathway as the cause of the AV block. The patient's AV nodal and His-Purkinje system conduction characteristics were otherwise normal. Radiofrequency catheter ablation of the pathway was successful in restoring normal AV conduction and eliminating her clinical symptoms. Pathways inserting into the AV junction can interfere with AV conduction. When present at a high burden, this type of AV block can be highly symptomatic. Catheter ablation techniques can be used to alleviate this type of AV block and restore normal AV conduction. Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Metastable states and energy flow pathway in square graphene resonators

NASA Astrophysics Data System (ADS)

Wang, Yisen; Zhu, Zhigang; Zhang, Yong; Huang, Liang

2018-01-01

Nonlinear interaction between flexural modes is critical to heat conductivity and mechanical vibration of two-dimensional materials such as graphene. Much effort has been devoted to understand the underlying mechanism. In this paper, we examine solely the out-of-plane flexural modes and identify their energy flow pathway during thermalization process. The key is the development of a universal scheme that numerically characterizes the strength of nonlinear interactions between normal modes. In particular, for our square graphene system, the modes are grouped into four classes by their distinct symmetries. The couplings are significantly larger within a class than between classes. As a result, the equations for the normal modes in the same class as the initially excited one can be approximated by driven harmonic oscillators, therefore, they get energy almost instantaneously. Because of the hierarchical organization of the mode coupling, the energy distribution among the modes will arrive at a stable profile, where most of the energy is localized on a few modes, leading to the formation of "natural package" and metastable states. The dynamics for modes in other symmetry classes follows a Mathieu type of equation, thus, interclass energy flow, when the initial excitation energy is small, starts typically when there is a mode that lies in the unstable region in the parameter space of Mathieu equation. Due to strong coupling of the modes inside the class, the whole class will get energy and be lifted up by the unstable mode. This characterizes the energy flow pathway of the system. These results bring fundamental understandings to the Fermi-Pasta-Ulam problem in two-dimensional systems with complex potentials, and reveal clearly the physical picture of dynamical interactions between the flexural modes, which will be crucial to the understanding of their abnormal contribution to heat conduction and nonlinear mechanical vibrations.

Sampling based State of Health estimation methodology for Li-ion batteries

NASA Astrophysics Data System (ADS)

Camci, Fatih; Ozkurt, Celil; Toker, Onur; Atamuradov, Vepa

2015-03-01

Storage and management of energy is becoming a more and more important problem every day, especially for electric and hybrid vehicle applications. Li-ion battery is one of the most important technological alternatives for high capacity energy storage and related industrial applications. State of Health (SoH) of Li-ion batteries plays a critical role in their deployment from economic, safety, and availability aspects. Most, if not all, of the studies related to SoH estimation focus on the measurement of a new parameter/physical phenomena related to SoH, or development of new statistical/computational methods using several parameters. This paper presents a new approach for SoH estimation for Li-ion battery systems with multiple battery cells: The main idea is a new circuit topology which enables separation of battery cells into two groups, main and test batteries, whenever a SoH related measurement is to be conducted. All battery cells will be connected to the main battery during the normal mode of operation. When a measurement is needed for SoH estimation, some of the cells will be separated from the main battery, and SoH estimation related measurements will be performed on these units. Compared to classical SoH measurement methods which deal with whole battery system, the proposed method estimates the SoH of the system by separating a small but representative set of cells. While SoH measurements are conducted on these isolated cells, remaining cells in the main battery continue to function in normal mode, albeit in slightly reduced performance levels. Preliminary experimental results are quite promising, and validate the feasibility of the proposed approach. Technical details of the proposed circuit architecture are also summarized in the paper.

A State-trait Analysis of Alpha Density and Personality Variables in a Normal Population

ERIC Educational Resources Information Center

Degood, Douglas E.; Valle, Ronald S.

1975-01-01

This paper examined the relationship of some selected trait measures of personality with resting samples of alpha density in a normal population and the implications of such data for a state-trait approach to alpha and the experiential states associated with alpha. (Author/RK)

Quantitative thermal sensory testing -- value of testing for both cold and warm sensation detection in evaluation of small fiber neuropathy.

PubMed

Shukla, Garima; Bhatia, Manvir; Behari, Madhuri

2005-10-01

Small fiber neuropathy is a common neurological disorder, often missed or ignored by physicians, since examination and routine nerve conduction studies are usually normal in this condition. Many methods including quantitative thermal sensory testing are currently being used for early detection of this condition, so as to enable timely investigation and treatment. This study was conducted to assess the yield of quantitative thermal sensory testing in diagnosis of small fiber neuropathy. We included patients presenting with history suggestive of positive and/or negative sensory symptoms, with normal examination findings, clinically suggestive of small fiber neuropathy, with normal or minimally abnormal routine nerve conduction studies. These patients were subjected to quantitative thermal sensory testing using a Medoc TSA-II Neurosensory analyser at two sites and for two modalities. QST data were compared with those in 120 normal healthy controls. Twenty-five patients (16 males, 9 females) with mean age 46.8+/-16.6 years (range: 21-75 years) were included in the study. The mean duration of symptoms was 1.6+/-1.6 years (range: 3 months-6 years). Eighteen patients (72%) had abnormal thresholds in at least one modality. Thermal thresholds were normal in 7 out of the 25 patients. This study demonstrates that quantitative thermal sensory testing is a fairly sensitive method for detection of small fiber neuropathy especially in patients with normal routine nerve conduction studies.

Exercises in anatomy: the normal heart.

PubMed

Anderson, Robert H; Sarwark, Anne; Spicer, Diane E; Backer, Carl L

2014-01-01

In this series of videoclips, we analyze the anatomy of the normal heart. We begin our overview by emphasizing the need, in the current era, to describe the heart in attitudinally appropriate fashion. Increasingly, clinicians are demonstrating the features of the heart as it is located within the body. It is no longer satisfactory, therefore, to describe these components in a ‘Valentine’ fashion, as continues to be the case in most textbooks of normal or cardiac anatomy. We then emphasize the importance of the so-called morphological method, which states that structures within the heart should be defined on the basis of their own intrinsic morphology, and not according to other parts, which are themselves variable. We continue by using this concept to show how the appendages serve to distinguish between the atrial chambers, while the apical trabecular components provide the features to distinguish the ventricles. We then return to the cardiac chambers, emphasizing features of surgical significance, in particular the locations of the cardiac conduction tissues. We proceed by examining the cardiac valves, and conclude by providing a detailed analysis of the septal structures. © The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Spin textures on general surfaces of the correlated topological insulator SmB6

NASA Astrophysics Data System (ADS)

Baruselli, Pier Paolo; Vojta, Matthias

2016-05-01

Employing the k .p expansion for a family of tight-binding models for SmB6, we analytically compute topological surface states on a generic (l m n ) surface. We show how the Dirac-cone spin structure depends on model ingredients and on the angle θ between the surface normal and the main crystal axes. We apply the general theory to (001), (110), (111), and (210) surfaces, for which we provide concrete predictions for the spin pattern of surface states which we also compare with tight-binding results. As shown in previous work, the spin pattern on a (001 ) surface can be related to the value of mirror Chern numbers, and we explore the possibility of topological phase transitions between states with different mirror Chern numbers and the associated change of the spin structure of surface states. Such transitions may be accessed by varying either the hybridization between conduction and f electrons or the crystal-field splitting of the low-energy f multiplets, and we compute corresponding phase diagrams. Experimentally, chemical doping is a promising route to realize such transitions.

First-Principles Correlated Approach to the Normal State of Strontium Ruthenate

PubMed Central

Acharya, S.; Laad, M. S.; Dey, Dibyendu; Maitra, T.; Taraphder, A.

2017-01-01

The interplay between multiple bands, sizable multi-band electronic correlations and strong spin-orbit coupling may conspire in selecting a rather unusual unconventional pairing symmetry in layered Sr2RuO4. This mandates a detailed revisit of the normal state and, in particular, the T-dependent incoherence-coherence crossover. Using a modern first-principles correlated view, we study this issue in the actual structure of Sr2RuO4 and present a unified and quantitative description of a range of unusual physical responses in the normal state. Armed with these, we propose that a new and important element, that of dominant multi-orbital charge fluctuations in a Hund’s metal, may be a primary pair glue for unconventional superconductivity. Thereby we establish a connection between the normal state responses and superconductivity in this system. PMID:28220879

Hydraulic Conductivity Estimation using Bayesian Model Averaging and Generalized Parameterization

NASA Astrophysics Data System (ADS)

Tsai, F. T.; Li, X.

2006-12-01

Non-uniqueness in parameterization scheme is an inherent problem in groundwater inverse modeling due to limited data. To cope with the non-uniqueness problem of parameterization, we introduce a Bayesian Model Averaging (BMA) method to integrate a set of selected parameterization methods. The estimation uncertainty in BMA includes the uncertainty in individual parameterization methods as the within-parameterization variance and the uncertainty from using different parameterization methods as the between-parameterization variance. Moreover, the generalized parameterization (GP) method is considered in the geostatistical framework in this study. The GP method aims at increasing the flexibility of parameterization through the combination of a zonation structure and an interpolation method. The use of BMP with GP avoids over-confidence in a single parameterization method. A normalized least-squares estimation (NLSE) is adopted to calculate the posterior probability for each GP. We employee the adjoint state method for the sensitivity analysis on the weighting coefficients in the GP method. The adjoint state method is also applied to the NLSE problem. The proposed methodology is implemented to the Alamitos Barrier Project (ABP) in California, where the spatially distributed hydraulic conductivity is estimated. The optimal weighting coefficients embedded in GP are identified through the maximum likelihood estimation (MLE) where the misfits between the observed and calculated groundwater heads are minimized. The conditional mean and conditional variance of the estimated hydraulic conductivity distribution using BMA are obtained to assess the estimation uncertainty.

Evolution of Neural Networks for the Prediction of Hydraulic Conductivity as a Function of Borehole Geophysical Logs: Shobasama Site, Japan

NASA Astrophysics Data System (ADS)

Reeves, P.; McKenna, S. A.; Takeuchi, S.; Saegusa, H.

2003-12-01

In situ measurements of hydraulic conductivity in fractured rocks are expensive to acquire. Borehole geophysical measurements are relatively inexpensive to acquire but do not provide direct information on hydraulic conductivity. These geophysical measurements quantify properties of the rock that influence the hydraulic conductivity and it may be possible to employ a non-linear combination of these measurements to estimate hydraulic conductivity. Geophysical measurements collected in fractured granite at the Shobasama site in central Japan were used as the input to a feed-forward neural network. A simple genetic algorithm was used to simultaneously evolve the architecture and parameters of the neural network as well as determine an optimal subset of geophysical measurements for the prediction of hydraulic conductivity. The initial estimation procedure focused on predicting the class of the hydraulic conductivity, high, medium or low, from the geophysical measurements. This estimation was done while using the genetic algorithm to simultaneously determine the most important geophysical logs and optimize the architecture of the neural network. Results show that certain geophysical logs provide more information than others- most notably the short-normal resistivity, micro-resistivity, porosity and sonic logs provided the most information on hydraulic conductivity. The neural network produced excellent training results with accuracy of 90 percent or greater, but was unable to produce accurate predictions of the hydraulic conductivity class In the second phase of calculations, the selection of geophysical measurements is limited to only those that provide significant information. Additionally, this second phase predicts transmissivity instead of hydraulic conductivity in order to account for the differences in the length of the hydraulic test zones. Resulting predictions of transmissivity exhibit conditional bias with maximum prediction errors of three orders of magnitude occurring at the extreme measurement values. Results of these simulations indicate that the most informative geophysical measurements for the prediction of transmissivity are depth and sonic velocity. The long normal resistivity and self potential geophysical measurements are moderately informative. In addition, it was found that porosity and crack counts (clear, open, or hairline) do not inform predictions of transmissivity. This work was funded by the Japan Nuclear Cycle Development Institute. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94-AL-85000

Field-tuned superconductor-insulator transitions and Hall resistance in thin polycrystalline MoN films

NASA Astrophysics Data System (ADS)

Makise, Kazumasa; Ichikawa, Fusao; Asano, Takayuki; Shinozaki, Bunju

2018-02-01

We report on the superconductor-insulator transitions (SITs) of disordered molybdenum nitride (MoN) thin films on (1 0 0) MgO substrates as a function of the film thickness and magnetic fields. The T c of the superconducting MoN films, which exhibit a sharp superconducting transition, monotonically decreases as the normal state R sq increases with a decreasing film thickness. For several films with different thicknesses, we estimate the critical field H c and the product zν  ≃  0.6 of the dynamical exponent z and the correlation length exponent ν using a finite scaling analysis. The value of this product can be explained by the (2  +  1) XY model. We found that the Hall resistance ΔR xy (H) is maximized when the magnetic field satisfies H HP(T) \\propto |1  -  T/T C0| in the superconducting state and also in the normal states owning to the superconducting fluctuation corresponding to the ghost critical magnetic field. We measured the Hall conductivity δσ xy (H)  =  σ xy (H)  -  σ xyn and fit the Gaussian approximation theory for δσ xy (H) to the experimental data. Agreement between the data and the theory beyond H c suggests the survival of the Cooper pair in the insulating region of the SIT.

Field-tuned superconductor-insulator transitions and Hall resistance in thin polycrystalline MoN films.

PubMed

Makise, Kazumasa; Ichikawa, Fusao; Asano, Takayuki; Shinozaki, Bunju

2018-02-14

We report on the superconductor-insulator transitions (SITs) of disordered molybdenum nitride (MoN) thin films on (1 0 0) MgO substrates as a function of the film thickness and magnetic fields. The T c of the superconducting MoN films, which exhibit a sharp superconducting transition, monotonically decreases as the normal state R sq increases with a decreasing film thickness. For several films with different thicknesses, we estimate the critical field H c and the product zν  ≃  0.6 of the dynamical exponent z and the correlation length exponent ν using a finite scaling analysis. The value of this product can be explained by the (2  +  1) XY model. We found that the Hall resistance ΔR xy (H) is maximized when the magnetic field satisfies H HP (T) [Formula: see text] |1  -  T/T C0 | in the superconducting state and also in the normal states owning to the superconducting fluctuation corresponding to the ghost critical magnetic field. We measured the Hall conductivity δσ xy (H)  =  σ xy (H)  -  [Formula: see text] and fit the Gaussian approximation theory for δσ xy (H) to the experimental data. Agreement between the data and the theory beyond H c suggests the survival of the Cooper pair in the insulating region of the SIT.

Superconductivity driven by pairing of the coherent parts of the physical electrons

NASA Astrophysics Data System (ADS)

Su, Yuehua; Zhang, Chao

2018-03-01

How the superconductivity in unconventional superconductors emerges from the diverse mother normal states is still a big puzzle. Whatever the mother normal states are the superconductivity is normal with BCS-like behaviours of the paired quasiparticles in condensation. To reconcile the diverse mother normal states and the normal superconductivity in unconventional superconductors, we revisit a proposal that the emergence of the low-energy coherent parts of the physical electrons, which survive from the interaction correlations, is an essential prerequisite for superconductivity. The superconductivity is driven by the pair condensation of these coherent parts of the physical electrons. Moreover the incoherent parts of the physical electrons can enhance the superconducting transition temperature Tc although they are not in driving role in the emergence of the superconductivity. Some experimental responses of the coherent parts of the physical electrons are predicted.

Alternating Wolff-Parkinson-White syndrome associated with attack of angina

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

Mangiafico, R.A.; Petralito, A.; Grimaldi, D.R.

1990-07-01

In a patient with Wolff-Parkinson-White syndrome and an inferior-posterior bypass tract, transient restoration of normal conduction occurred during an attack of angina. The ECG pattern of inferior posterior ischemia was present when the conduction was normal. Thallium scintigraphy showed a reversible posterolateral perfusion defect. The possible mechanisms for production of intermittent preexcitation are discussed.

Thermostructural Evaluation of Joggle Region on the Shuttle Orbiter's Wing Leading Edge

NASA Technical Reports Server (NTRS)

Walker, Sandra P.; Warren, Jerry E.

2012-01-01

An investigation was initiated to determine the cause of coating spallation occurring on the Shuttle Orbiter's wing leading edge panels in the slip-side joggle region. The coating spallation events were observed, post flight, on differing panels on different missions. As part of the investigation, the high re-entry heating occurring on the joggles was considered here as a possible cause. Thus, a thermostructural evaluation was conducted to determine the detailed state-of-stress in the joggle region during re-entry and the feasibility of a laboratory test on a local joggle specimen to replicate this state-of-stress. A detailed three-dimensional finite element model of a panel slip-side joggle region was developed. Parametric and sensitivity studies revealed significant stresses occur in the joggle during peak heating. A critical interlaminar normal stress concentration was predicted in the substrate at the coating interface and was confined to the curved joggle region. Specifically, the high interlaminar normal stress is identified to be the cause for the occurrence of failure in the form of local subsurface material separation occurring in the slip-side joggle. The predicted critical stresses are coincident with material separations that had been observed with microscopy in joggle specimens obtained from flight panels.

Characterizing Normal Groundwater Chemistry in Hawaii

NASA Astrophysics Data System (ADS)

Tachera, D.; Lautze, N. C.; Thomas, D. M.; Whittier, R. B.; Frazer, L. N.

2017-12-01

Hawaii is dependent on groundwater resources, yet how water moves through the subsurface is not well understood in many locations across the state. As marine air moves across the islands water evaporates from the ocean, along with trace amounts of sea-salt ions, and interacts with the anthropogenic and volcanic aerosols (e.g. sulfuric acid, ammonium sulfate, HCl), creating a slightly more acidic rain. When this rain falls, it has a chemical signature distinctive of past processes. As this precipitation infiltrates through soil it may pick up another distinctive chemical signature associated with land use and degree of soil development, and as it flows through the underlying geology, its chemistry is influenced by the host rock. We are currently conducting an investigation of groundwater chemistry in selected aquifer areas of Hawaii, having diverse land use, land cover, and soil development conditions, in an effort to investigate and document what may be considered a "normal" water chemistry for an area. Through this effort, we believe we better assess anomalies due to contamination events, hydrothermal alteration, and other processes; and we can use this information to better understand groundwater flow direction. The project has compiled a large amount of precipitation, soil, and groundwater chemistry data in the three focus areas distributed across in the State of Hawaii. Statistical analyses of these data sets will be performed in an effort to determine what is "normal" and what is anomalous chemistry for a given area. Where possible, results will be used to trace groundwater flow paths. Methods and preliminary results will be presented.

Ballistic superconductivity in semiconductor nanowires.

PubMed

Zhang, Hao; Gül, Önder; Conesa-Boj, Sonia; Nowak, Michał P; Wimmer, Michael; Zuo, Kun; Mourik, Vincent; de Vries, Folkert K; van Veen, Jasper; de Moor, Michiel W A; Bommer, Jouri D S; van Woerkom, David J; Car, Diana; Plissard, Sébastien R; Bakkers, Erik P A M; Quintero-Pérez, Marina; Cassidy, Maja C; Koelling, Sebastian; Goswami, Srijit; Watanabe, Kenji; Taniguchi, Takashi; Kouwenhoven, Leo P

2017-07-06

Semiconductor nanowires have opened new research avenues in quantum transport owing to their confined geometry and electrostatic tunability. They have offered an exceptional testbed for superconductivity, leading to the realization of hybrid systems combining the macroscopic quantum properties of superconductors with the possibility to control charges down to a single electron. These advances brought semiconductor nanowires to the forefront of efforts to realize topological superconductivity and Majorana modes. A prime challenge to benefit from the topological properties of Majoranas is to reduce the disorder in hybrid nanowire devices. Here we show ballistic superconductivity in InSb semiconductor nanowires. Our structural and chemical analyses demonstrate a high-quality interface between the nanowire and a NbTiN superconductor that enables ballistic transport. This is manifested by a quantized conductance for normal carriers, a strongly enhanced conductance for Andreev-reflecting carriers, and an induced hard gap with a significantly reduced density of states. These results pave the way for disorder-free Majorana devices.

Enhanced Andreev reflection in gapped graphene

NASA Astrophysics Data System (ADS)

Majidi, Leyla; Zareyan, Malek

2012-08-01

We theoretically demonstrate unusual features of superconducting proximity effect in gapped graphene that presents a pseudospin symmetry-broken ferromagnet with a net pseudomagnetization. We find that the presence of a band gap makes the Andreev conductance of graphene superconductor/pseudoferromagnet (S/PF) junction to behave similar to that of a graphene ferromagnet-superconductor junction. The energy gap ΔN can enhance the pseudospin inverted Andreev conductance of S/PF junction to reach a limiting maximum value for ΔN≫μ, which depending on the bias voltage can be larger than the value for the corresponding junction with no energy gap. We further demonstrate a damped-oscillatory behavior for the local density of states of the PF region of S/PF junction and a long-range crossed Andreev reflection process in PF/S/PF structure with antiparallel alignment of pseudomagnetizations of PFs, which confirm that, in this respect, the gapped normal graphene behaves like a ferromagnetic graphene.

Chalcogen doping at anionic site: A scheme towards more dispersive valence band in CuAlO2

NASA Astrophysics Data System (ADS)

Mazumder, Nilesh; Sen, Dipayan; Chattopadhyay, Kalyan Kumar

2013-02-01

Using first-principles calculations, we propose to enhance the dispersion of the top of valence band at high-symmetry points by selective introduction of chalcogen (Ch) impurities at oxygen site. As ab-plane hole mobility of CuAlO2 is large enough to support a band-conduction model over a polaronic one at room temperature [M. S. Lee et al. Appl. Phys. Lett. 79, 2029, (2001); J. Tate et al. Phys. Rev. B 80, 165206, (2009)], we examine its electronic and optical properties normal to c-axis. Intrinsic indirectness of energy-gap at Γ-point can be effectively removed along with substantial increase in density of states near Fermi level (EF) upon Ch addition. This can be attributed to S 2p-Cu 3d interaction just at or below EF, which should result in significantly improved carrier mobility and conductivity profile for this important p-type TCO.

Anomalous phonon behavior in superconducting CaKFe 4 As 4 : An optical study

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

Yang, Run; Dai, Yaomin; Xu, Bing

Here, the temperature dependence of ab-plane optical conductivity of CaKFe 4As 4 has been measured below and above its superconducting transition temperature T c≃35.5 K. In the normal state, analysis with the two-Drude model reveals a T-linear scattering rate for the coherent response, which suggests strong spin-fluctuation scattering. Below the superconducting transition, the optical conductivity below 120 cm –1 vanishes, indicating nodeless gap(s). The Mattis-Bardeen fitting in the superconducting state gives two gaps of Δ 1 ≃ 9 meV and Δ 2 ≃ 14 meV, in good agreement with recent angle-resolved photoemission spectroscopy (ARPES) results. In addition, around 255 cmmore » –1, we observe two different infrared-active Fe-As modes with obvious asymmetric lineshape, originating from strong coupling between lattice vibrations and spin or charge excitations. Considering a moderate Hund's rule coupling determined from spectral weight analysis, we propose that the strong fluctuations induced by the coupling between itinerant carriers and local moments may affect the phonon mode, and the electron-phonon coupling through the spin channel is likely to play an important role in the unconventional pairing in iron-based superconductors.« less

Weak antilocalization effect due to topological surface states in Bi2Se2.1Te0.9

NASA Astrophysics Data System (ADS)

Shrestha, K.; Graf, D.; Marinova, V.; Lorenz, B.; Chu, C. W.

2017-10-01

We have investigated the weak antilocalization (WAL) effect in the p-type Bi2Se2.1Te0.9 topological system. The magnetoconductance shows a cusp-like feature at low magnetic fields, indicating the presence of the WAL effect. The WAL curves measured at different tilt angles merge together when they are plotted as a function of the normal field components, showing that surface states dominate the magnetoconductance in the Bi2Se2.1Te0.9 crystal. We have calculated magnetoconductance per conduction channel and applied the Hikami-Larkin-Nagaoka formula to determine the physical parameters that characterize the WAL effect. The number of conduction channels and the phase coherence length do not change with temperature up to T = 5 K. In addition, the sample shows a large positive magnetoresistance that reaches 1900% under a magnetic field of 35 T at T = 0.33 K with no sign of saturation. The magnetoresistance value decreases with both increasing temperature and tilt angle of the sample surface with respect to the magnetic field. The large magnetoresistance of topological insulators can be utilized in future technology such as sensors and memory devices.

Student Design Challenges in Capillary Flow

NASA Technical Reports Server (NTRS)

Stocker, Dennis P.; Wollman, Andrew; Hall, Nancy R.; Weislogel, Mark; DeLombard, Richard

2016-01-01

For some grade 8-12 students, capillary flow has bridged the gap between the classroom and research facility, from normal gravity to microgravity. In the past four years, NASA and the Portland State University (PSU) have jointly challenged students to design test cells, using Computer-Aided Design (CAD), to study capillary action in microgravity as PSU has done on the International Space Station (ISS). Using the student-submitted CAD drawings, the test cells were manufactured by PSU and tested in their 2.1-second drop tower. The microgravity results were made available online for student analysis and reporting. Over 100 such experiments have been conducted, where there has been participation from 15 states plus a German school for the children of U.S. military personnel. In 2016, a related NASA challenge was held in partnership with the ASGSR, again, based on the research conducted by PSU. In this challenge, grade 9-12 students designed and built devices using capillary action to launch droplets as far as possible in NASAs 2.2 Second Drop Tower. Example results will be presented by students at this conference. The challenges engage students in ISS science and technology and can inspire them to pursue technical careers.

Effects of personal experiences on the interpretation of the meaning of colours used in the displays and controls in electric control panels.

PubMed

Lee, Inseok; Hwang, Won-Gue

2015-01-01

A survey was conducted to examine how personal experiences affect the interpretation of the meaning of display and control colours on electric control panels (ECPs). In Korea, the red light on ECPs represents a normal state of operation, while the green light represents a stopped state of operation; this appears to contradict the general stereotypes surrounding these colours. The survey results indicated that the participants who had experience in using ECPs interpreted the colour meaning differently from the other participant group. More than half of the experienced participants regarded the coloured displays and controls as they were designed, while most participants in the other group appeared to interpret the colours in accordance with the stereotypes. It is presumed that accidents related to human errors can occur when non-experienced people use the ECPs, which are easily accessible in many buildings. Practitioner Summary: A survey was conducted to investigate how personal experiences affect the interpretation of the function meanings of coloured lights on electrical control panels. It was found that the interpretation varies according to personal experiences, which can induce accidents related to human errors while operating electrical equipment.

Anomalous phonon behavior in superconducting CaKFe 4 As 4 : An optical study

DOE PAGES

Yang, Run; Dai, Yaomin; Xu, Bing; ...

2017-02-08

Here, the temperature dependence of ab-plane optical conductivity of CaKFe 4As 4 has been measured below and above its superconducting transition temperature T c≃35.5 K. In the normal state, analysis with the two-Drude model reveals a T-linear scattering rate for the coherent response, which suggests strong spin-fluctuation scattering. Below the superconducting transition, the optical conductivity below 120 cm –1 vanishes, indicating nodeless gap(s). The Mattis-Bardeen fitting in the superconducting state gives two gaps of Δ 1 ≃ 9 meV and Δ 2 ≃ 14 meV, in good agreement with recent angle-resolved photoemission spectroscopy (ARPES) results. In addition, around 255 cmmore » –1, we observe two different infrared-active Fe-As modes with obvious asymmetric lineshape, originating from strong coupling between lattice vibrations and spin or charge excitations. Considering a moderate Hund's rule coupling determined from spectral weight analysis, we propose that the strong fluctuations induced by the coupling between itinerant carriers and local moments may affect the phonon mode, and the electron-phonon coupling through the spin channel is likely to play an important role in the unconventional pairing in iron-based superconductors.« less

Mobilizing mobile medical units for hurricane relief: the United States Public Health Service and Broward County Health Department response to hurricane Wilma, Broward County, Florida.

PubMed

Taylor, Melanie M; Stokes, William S; Bajuscak, Ronald; Serdula, Mary; Siegel, Karen L; Griffin, Brian; Keiser, Jeffrey; Agate, Lisa; Kite-Powell, Aaron; Roach, David; Humbert, Nancy; Brusuelas, Kristin; Shekar, Sam S

2007-01-01

To describe the outcomes of a collaborative response of federal, state, county, and local agencies in conducting syndromic surveillance and delivering medical care to persons affected by the storm through the use of mobile medical units. Nine mobile medical vans were staffed with medical personnel to deliver care in communities affected by the storm. Individual patient encounter information was collected. A total of 14,033 housing units were approached and checked for occupants. Of residents with whom contact was made, approximately 10 percent required medical assessment in their homes; 3,218 clients were medically evaluated on the mobile medical vans. Sixty-two percent of clients were female. The most common presenting complaints included normal health maintenance (59%), upper respiratory tract illness (10%), and other illness (10%). Injuries occurred in 9 percent. A total of 1,531 doses of medications were dispensed from the mobile medical units during the response. Mobile medical units provided an efficient means to conduct syndromic surveillance and to reach populations in need of medical care who were unable to access fixed local medical facilities.

Complex conductivity of volcanic rocks and the geophysical mapping of alteration in volcanoes

NASA Astrophysics Data System (ADS)

Ghorbani, A.; Revil, A.; Coperey, A.; Soueid Ahmed, A.; Roque, S.; Heap, M. J.; Grandis, H.; Viveiros, F.

2018-05-01

Induced polarization measurements can be used to image alteration at the scale of volcanic edifices to a depth of few kilometers. Such a goal cannot be achieved with electrical conductivity alone, because too many textural and environmental parameters influence the electrical conductivity of volcanic rocks. We investigate the spectral induced polarization measurements (complex conductivity) in the frequency band 10 mHz-45 kHz of 85 core samples from five volcanoes: Merapi and Papandayan in Indonesia (32 samples), Furnas in Portugal (5 samples), Yellowstone in the USA (26 samples), and Whakaari (White Island) in New Zealand (22 samples). This collection of samples covers not only different rock compositions (basaltic andesite, andesite, trachyte and rhyolite), but also various degrees of alteration. The specific surface area is found to be correlated to the cation exchange capacity (CEC) of the samples measured by the cobalthexamine method, both serving as rough proxies of the hydrothermal alteration experienced by these materials. The in-phase (real) conductivity of the samples is the sum of a bulk contribution associated with conduction in the pore network and a surface conductivity that increases with alteration. The quadrature conductivity and the normalized chargeability are two parameters related to the polarization of the electrical double layer coating the minerals of the volcanic rocks. Both parameters increase with the degree of alteration. The surface conductivity, the quadrature conductivity, and the normalized chargeability (defined as the difference between the in-phase conductivity at high and low frequencies) are linearly correlated to the CEC normalized by the bulk tortuosity of the pore space. The effects of temperature and pyrite-content are also investigated and can be understood in terms of a physics-based model. Finally, we performed a numerical study of the use of induced polarization to image the normalized chargeability of a volcanic edifice. Induced polarization tomography can be used to map alteration of volcanic edifices with applications to geohazard mapping.

Weakly coupled map lattice models for multicellular patterning and collective normalization of abnormal single-cell states

NASA Astrophysics Data System (ADS)

García-Morales, Vladimir; Manzanares, José A.; Mafe, Salvador

2017-04-01

We present a weakly coupled map lattice model for patterning that explores the effects exerted by weakening the local dynamic rules on model biological and artificial networks composed of two-state building blocks (cells). To this end, we use two cellular automata models based on (i) a smooth majority rule (model I) and (ii) a set of rules similar to those of Conway's Game of Life (model II). The normal and abnormal cell states evolve according to local rules that are modulated by a parameter κ . This parameter quantifies the effective weakening of the prescribed rules due to the limited coupling of each cell to its neighborhood and can be experimentally controlled by appropriate external agents. The emergent spatiotemporal maps of single-cell states should be of significance for positional information processes as well as for intercellular communication in tumorigenesis, where the collective normalization of abnormal single-cell states by a predominantly normal neighborhood may be crucial.

Weakly coupled map lattice models for multicellular patterning and collective normalization of abnormal single-cell states.

PubMed

García-Morales, Vladimir; Manzanares, José A; Mafe, Salvador

2017-04-01

We present a weakly coupled map lattice model for patterning that explores the effects exerted by weakening the local dynamic rules on model biological and artificial networks composed of two-state building blocks (cells). To this end, we use two cellular automata models based on (i) a smooth majority rule (model I) and (ii) a set of rules similar to those of Conway's Game of Life (model II). The normal and abnormal cell states evolve according to local rules that are modulated by a parameter κ. This parameter quantifies the effective weakening of the prescribed rules due to the limited coupling of each cell to its neighborhood and can be experimentally controlled by appropriate external agents. The emergent spatiotemporal maps of single-cell states should be of significance for positional information processes as well as for intercellular communication in tumorigenesis, where the collective normalization of abnormal single-cell states by a predominantly normal neighborhood may be crucial.

Estimating systemic exposure to levonorgestrel from an oral contraceptive.

PubMed

Basaraba, Cale N; Westhoff, Carolyn L; Pike, Malcolm C; Nandakumar, Renu; Cremers, Serge

2017-04-01

The gold standard for measuring oral contraceptive (OC) pharmacokinetics is the 24-h steady-state area under the curve (AUC). We conducted this study to assess whether limited sampling at steady state or measurements following use of one or two OCs could provide an adequate proxy in epidemiological studies for the progestin 24-h steady-state AUC of a particular OC. We conducted a 13-sample, 24-h pharmacokinetic study on both day 1 and day 21 of the first cycle of a monophasic OC containing 30-mcg ethinyl estradiol and 150-mcg levonorgestrel (LNG) in 17 normal-weight healthy White women and a single-dose 9-sample study of the same OC after a 1-month washout. We compared the 13-sample steady-state results with several steady-state and single-dose results calculated using parsimonious sampling schemes. The 13-sample steady-state 24-h LNG AUC was highly correlated with the steady-state 24-h trough value [r=0.95; 95% confidence interval (0.85, 0.98)] and with the steady-state 6-, 8-, 12- and 16-h values (0.92≤r≤0.95). The trough values after one or two doses were moderately correlated with the steady-state 24-h AUC value [r=0.70; 95% CI (0.27, 0.90) and 0.77; 95% CI (0.40, 0.92), respectively]. Single time-point concentrations at steady state and after administration of one or two OCs gave highly to moderately correlated estimates of steady-state LNG AUC. Using such measures could facilitate prospective pharmaco-epidemiologic studies of the OC and its side effects. A single time-point LNG concentration at steady state is an excellent proxy for complete and resource-intensive steady-state AUC measurement. The trough level after two single doses is a fair proxy for steady-state AUC. These results provide practical tools to facilitate large studies to investigate the relationship between systemic LNG exposure and side effects in a real-life setting. Copyright © 2017 Elsevier Inc. All rights reserved.

Reagentless Detection of Low-Molecular-Weight Triamterene Using Self-Doped TiO2 Nanotubes.

PubMed

Hudari, Felipe F; Bessegato, Guilherme G; Bedatty Fernandes, Flávio C; Zanoni, Maria V B; Bueno, Paulo R

2018-06-19

TiO 2 nanotube electrodes were self-doped by electrochemical cathodic polarization, potentially converting Ti 4+ into Ti 3+ , and thereby increasing both the normalized conductance and capacitance of the electrodes. One-hundred (from 19.2 ± 0.1 μF cm -2 to 1.9 ± 0.1 mF cm -2 for SD-TNT) and two-fold (from ∼6.2 to ∼14.4 mS cm -2 ) concomitant increases in capacitance and conductance, respectively, were achieved in self-doped TiO 2 nanotubes; this was compared with the results for their undoped counterparts. The increases in the capacitance and conductance indicate that the Ti 3+ states enhance the density of the electronic states; this is attributed to an existing relationship between the conductance and capacitance for nanoscale structures built on macroscopic electrodes. The ratio between the conductance and capacitance was used to detect and quantify, in a reagentless manner, the triamterene (TRT) diuretic by designing an appropriate doping level of TiO 2 nanotubes. The sensitivity was improved when using immittance spectroscopy (Patil et al. Anal. Chem. 2015, 87, 944-950; Bedatty Fernandes et al. Anal. Chem. 2015, 87, 12137-12144) (2.4 × 10 6 % decade -1 ) compared to cyclic voltammetry (5.8 × 10 5 % decade -1 ). Furthermore, a higher linear range from 0.5 to 100 μmol L -1 (5.0 to 100 μmol L -1 for cyclic voltammetry measurements) and a lower limit-of-detection of approximately 0.2 μmol L -1 were achieved by using immittance function methodology (better than the 4.1 μmol L -1 obtained by using cyclic voltammetry).

Effects of cardiac energy efficiency in diastolic heart failure: assessment with positron emission tomography with 11C-acetate.

PubMed

Hasegawa, Shinji; Yamamoto, Kazuhiro; Sakata, Yasushi; Takeda, Yasuharu; Kajimoto, Katsufumi; Kanai, Yasukazu; Hori, Masatsugu; Hatazawa, Jun

2008-06-01

Diastolic heart failure (DHF) has become a high social burden, and its major underlying cardiovascular disease is hypertensive heart disease. However, the pathogenesis of DHF remains to be clarified. This study aimed to assess the effects of cardiac energy efficiency in DHF patients. (11)C-Acetate positron emission tomography and echocardiography were conducted in 11 DHF Japanese patients and 10 normal volunteers. The myocardial clearance rate of radiolabeled (11)C-acetate was measured to calculate the work metabolic index (WMI), an index of cardiac efficiency. The ratio of peak mitral E wave velocity to peak early diastolic septal myocardial velocity (E/e') was calculated to assess left ventricular (LV) filling pressure. The LV mass index was greater and the mean age was higher in the DHF patients than in the normal volunteers. There was no difference in WMI between the two groups. However, WMI varied widely among the DHF patients and was inversely correlated with E/e' (r=-0.699, p=0.017). In contrast, there was no correlation in the normal volunteers. In conclusion, the inefficiency of energy utilization is not a primary cause of diastolic dysfunction or DHF, and cardiac efficiency may not affect diastolic function in normal hearts. However, the energy-wasting state may induce the elevation of LV filling pressure in DHF patients, which was considered to principally result from the progressive diastolic dysfunction.

Temporal resistance variation of the second generation HTS tape during superconducting-to-normal state transition.

PubMed

Malginov, Vladimir A; Malginov, Andrey V; Fleishman, Leonid S

2013-01-01

The quench process in high-temperature superconducting (HTS) wires plays an important role in superconducting power devices, such as fault current limiters, magnets, cables, etc. The superconducting device should survive after the overheating due to quench. We studied the evolution of the resistance of the YBCO tape wire during the quench process with 1 ms time resolution for various excitation voltages. The resistive normal zone was found to be located in a domain of about 1-4 cm long. The normal state nucleation begins in 40-60 ms after voltage is applied across the HTS tape. In subsequent 200-300 ms other normal state regions appear. The normal domain heating continues in the following 5-10s that results in a factor of 2-3 increase of its resistance. Formation of the normal domain during the quench process follows the same stages for different excitation voltages. Characteristic domain sizes, lifetimes and temperatures are determined for all stages.

Laboratory investigation on effects of flood intermittency on river delta dynamics

NASA Astrophysics Data System (ADS)

Miller, K. L.; Kim, W.

2015-12-01

In order to simplify the complex hydrological variability of flow conditions, experiments modeling delta evolution are often conducted using a representative "channel-forming" flood flow and then relate results to field settings using an intermittency factor, defined as the fraction of total time at flood conditions. Although this intermittency factor makes it easier to investigate how variables, such as relative base level and/or sediment supply, affect delta dynamics, little is known about how this generalization to a single flow condition affects delta processes. We conducted a set of laboratory experiments with periodic flow conditions to determine the effects of intermittent discharges on delta evolution. During the experiment, flood with a set water discharge and sediment supply, cycles between periods of normal flow where the water flux is halved and the sediment discharge is turned off. For each run, the magnitude of the flood is held constant, but the duration is assigned differently, thus varying the intermittency between 1 and 0.2. We find that as the intermittency factor decreases (duration of each flood period decreases), the delta topset has a larger, more elongated area with a shallower slope as a result of reworking on the delta topset during normal flow conditions. During periods of normal flow, the system adjusts towards a new equilibrium state that then in turn acts as the initial condition for the subsequent flood period. Furthermore, the natural delta avulsion cycle becomes obscured by the flood cycles as the flood duration becomes shorter than the autogenic behavior. These results suggest that the adjustment timescale for differing flow conditions is a factor in determining the overall shape of the delta and behavior of the fluviodeltaic channels. We conclude, periods of normal flow when topset sediment is reworked, may be just as important to delta dynamics as periods of flood when sediment is supplied to the system.

Interneuron-mediated inhibition synchronizes neuronal activity during slow oscillation.

PubMed

Chen, Jen-Yung; Chauvette, Sylvain; Skorheim, Steven; Timofeev, Igor; Bazhenov, Maxim

2012-08-15

The signature of slow-wave sleep in the electroencephalogram (EEG) is large-amplitude fluctuation of the field potential, which reflects synchronous alternation of activity and silence across cortical neurons. While initiation of the active cortical states during sleep slow oscillation has been intensively studied, the biological mechanisms which drive the network transition from an active state to silence remain poorly understood. In the current study, using a combination of in vivo electrophysiology and thalamocortical network simulation, we explored the impact of intrinsic and synaptic inhibition on state transition during sleep slow oscillation. We found that in normal physiological conditions, synaptic inhibition controls the duration and the synchrony of active state termination. The decline of interneuron-mediated inhibition led to asynchronous downward transition across the cortical network and broke the regular slow oscillation pattern. Furthermore, in both in vivo experiment and computational modelling, we revealed that when the level of synaptic inhibition was reduced significantly, it led to a recovery of synchronized oscillations in the form of seizure-like bursting activity. In this condition, the fast active state termination was mediated by intrinsic hyperpolarizing conductances. Our study highlights the significance of both intrinsic and synaptic inhibition in manipulating sleep slow rhythms.

Interneuron-mediated inhibition synchronizes neuronal activity during slow oscillation

PubMed Central

Chen, Jen-Yung; Chauvette, Sylvain; Skorheim, Steven; Timofeev, Igor; Bazhenov, Maxim

2012-01-01

The signature of slow-wave sleep in the electroencephalogram (EEG) is large-amplitude fluctuation of the field potential, which reflects synchronous alternation of activity and silence across cortical neurons. While initiation of the active cortical states during sleep slow oscillation has been intensively studied, the biological mechanisms which drive the network transition from an active state to silence remain poorly understood. In the current study, using a combination of in vivo electrophysiology and thalamocortical network simulation, we explored the impact of intrinsic and synaptic inhibition on state transition during sleep slow oscillation. We found that in normal physiological conditions, synaptic inhibition controls the duration and the synchrony of active state termination. The decline of interneuron-mediated inhibition led to asynchronous downward transition across the cortical network and broke the regular slow oscillation pattern. Furthermore, in both in vivo experiment and computational modelling, we revealed that when the level of synaptic inhibition was reduced significantly, it led to a recovery of synchronized oscillations in the form of seizure-like bursting activity. In this condition, the fast active state termination was mediated by intrinsic hyperpolarizing conductances. Our study highlights the significance of both intrinsic and synaptic inhibition in manipulating sleep slow rhythms. PMID:22641778

Coaxial line configuration for microwave power transmission study of YBa2Cu3O(7-delta) thin films

NASA Technical Reports Server (NTRS)

Chorey, C. M.; Miranda, F. A.; Bhasin, K. B.

1991-01-01

Microwave transmission measurements through YBa2Cu3O(7-delta) (YBCO) high-transition-temperature superconducting thin films on lanthanum aluminate (LaAlO3) have been performed in a coaxial line at 10 GHz. LaAlO3 substrates were ultrasonically machined into washer-shaped discs, polished, and coated with laser-ablated YBCO. These samples were mounted in a 50-ohm coaxial air line to form a short circuit. The power transmitted through the films as a function of temperature was used to calculate the normal state conductivity and the magnetic penetration depth for the films.

Breakdown of the Simple Arrhenius Law in the Normal Liquid State.

PubMed

Thoms, Erik; Grzybowski, Andrzej; Pawlus, Sebastian; Paluch, Marian

2018-04-05

It is common practice to discuss the temperature effect on molecular dynamics of glass formers above the melting temperature in terms of the Arrhenius law. Using dielectric spectroscopy measurements of dc conductivity and structural relaxation time on the example of the typical glass former propylene carbonate, we provide experimental evidence that this practice is not justified. Our conclusions are supported by employing thermodynamic density scaling and the occurrence of inflection points in isothermal dynamic data measured at elevated pressure. Additionally, we propose a more suitable approach to describe the dynamics both above and below the inflection point based on a modified MYEGA model.

The effects of moisture on molecular sieve oxygen concentrators.

PubMed

Ikels, K G; Theis, C F

1985-01-01

Molecular sieve oxygen generating systems are receiving extensive laboratory and flight evaluation. Assessment of the molecular system has generally been conducted in the laboratory using clean dry air. In aircraft, however, the molecular sieve generator is supplied with engine bleed air which may not always be totally free of contaminants and water. Recent studies using bed washout technics have shown that the molecular sieve units, with 50% of the beds deactivated with water, still function normally with respect to product gas flow and O2 concentration. By utilizing the technics described in this paper, the moisture content or state of hydration of the molecular sieve can readily be determined.

Room-temperature annealing effects on the basal-plane resistivity of optimally doped YBa2Cu3O7-δ single crystals

NASA Astrophysics Data System (ADS)

Khadzhai, G. Ya.; Vovk, R. V.; Vovk, N. R.; Kamchatnaya, S. N.; Dobrovolskiy, O. V.

2018-02-01

We reveal that the temperature dependence of the basal-plane normal-state electrical resistance of optimally doped YBa2Cu3O7-δ single crystals can be with great accuracy approximated within the framework of the model of s-d electron-phonon scattering. This requires taking into account the fluctuation conductivity whose contribution exponentially increases with decreasing temperature and decreases with an increase of oxygen deficiency. Room-temperature annealing improves the sample and, thus, increases the superconducting transition temperature. The temperature of the 2D-3D crossover decreases during annealing.

Wavelet entropy characterization of elevated intracranial pressure.

PubMed

Xu, Peng; Scalzo, Fabien; Bergsneider, Marvin; Vespa, Paul; Chad, Miller; Hu, Xiao

2008-01-01

Intracranial Hypertension (ICH) often occurs for those patients with traumatic brain injury (TBI), stroke, tumor, etc. Pathology of ICH is still controversial. In this work, we used wavelet entropy and relative wavelet entropy to study the difference existed between normal and hypertension states of ICP for the first time. The wavelet entropy revealed the similar findings as the approximation entropy that entropy during ICH state is smaller than that in normal state. Moreover, with wavelet entropy, we can see that ICH state has the more focused energy in the low wavelet frequency band (0-3.1 Hz) than the normal state. The relative wavelet entropy shows that the energy distribution in the wavelet bands between these two states is actually different. Based on these results, we suggest that ICH may be formed by the re-allocation of oscillation energy within brain.

A normality bias in legal decision making.

PubMed

Prentice, Robert A; Koehler, Jonathan J

2003-03-01

It is important to understand how legal fact finders determine causation and assign blame. However, this process is poorly understood. Among the psychological factors that affect decision makers are an omission bias (a tendency to blame actions more than inactions [omissions] for bad results), and a normality bias (a tendency to react more strongly to bad outcomes that spring from abnormal rather than normal circumstances). The omission and normality biases often reinforce one another when inaction preserves the normal state and when action creates an abnormal state. But what happens when these biases push in opposite directions as they would when inaction promotes an abnormal state or when action promotes a normal state? Which bias exerts the stronger influence on the judgments and behaviors of legal decision makers? The authors address this issue in two controlled experiments. One experiment involves medical malpractice and the other involves stockbroker negligence. They find that jurors pay much more attention to the normality of conditions than to whether those conditions arose through acts or omissions. Defendants who followed a nontraditional medical treatment regime or who chose a nontraditional stock portfolio received more blame and more punishment for bad outcomes than did defendants who obtained equally poor results after recommending a traditional medical regime or a traditional stock portfolio. Whether these recommendations entailed an action or an omission was essentially irrelevant. The Article concludes with a discussion of the implications of a robust normality bias for American jurisprudence.

Statistical process control applied to mechanized peanut sowing as a function of soil texture.

PubMed

Zerbato, Cristiano; Furlani, Carlos Eduardo Angeli; Ormond, Antonio Tassio Santana; Gírio, Lucas Augusto da Silva; Carneiro, Franciele Morlin; da Silva, Rouverson Pereira

2017-01-01

The successful establishment of agricultural crops depends on sowing quality, machinery performance, soil type and conditions, among other factors. This study evaluates the operational quality of mechanized peanut sowing in three soil types (sand, silt, and clay) with variable moisture contents. The experiment was conducted in three locations in the state of São Paulo, Brazil. The track-sampling scheme was used for 80 sampling locations of each soil type. Descriptive statistics and statistical process control (SPC) were used to evaluate the quality indicators of mechanized peanut sowing. The variables had normal distributions and were stable from the viewpoint of SPC. The best performance for peanut sowing density, normal spacing, and the initial seedling growing stand was found for clayey soil followed by sandy soil and then silty soil. Sandy or clayey soils displayed similar results regarding sowing depth, which was deeper than in the silty soil. Overall, the texture and the moisture of clayey soil provided the best operational performance for mechanized peanut sowing.

Acoustic analysis of normal Saudi adult voices.

PubMed

Malki, Khalid H; Al-Habib, Salman F; Hagr, Abulrahman A; Farahat, Mohamed M

2009-08-01

To determine the acoustic differences between Saudi adult male and female voices, and to compare the acoustic variables of the Multidimensional Voice Program (MDVP) obtained from North American adults to a group of Saudi males and females. A cross-sectional survey of normal adult male and female voices was conducted at King Abdulaziz University Hospital, Riyadh, Kingdom of Saudi Arabia between March 2007 and December 2008. Ninety-five Saudi subjects sustained the vowel /a/ 6 times, and the steady state portion of 3 samples was analyzed and compared with the samples of the KayPentax normative voice database. Significant differences were found between Saudi and North American KayPentax database groups. In the male subjects, 15 of 33 MDVP variables, and 10 of 33 variables in the female subjects were found to be significantly different from the KayPentax database. We conclude that the acoustical differences may reflect laryngeal anatomical or tissue differences between the Saudi and the KayPentax database.

Modelling of steady state erosion of CFC actively water-cooled mock-up for the ITER divertor

NASA Astrophysics Data System (ADS)

Ogorodnikova, O. V.

2008-04-01

Calculations of the physical and chemical erosion of CFC (carbon fibre composite) monoblocks as outer vertical target of the ITER divertor during normal operation regimes have been done. Off-normal events and ELM's are not considered here. For a set of components under thermal and particles loads at glancing incident angle, variations in the material properties and/or assembly of defects could result in different erosion of actively-cooled components and, thus, in temperature instabilities. Operation regimes where the temperature instability takes place are investigated. It is shown that the temperature and erosion instabilities, probably, are not a critical point for the present design of ITER vertical target if a realistic variation of material properties is assumed, namely, the difference in the thermal conductivities of the neighbouring monoblocks is 20% and the maximum allowable size of a defect between CFC armour and cooling tube is +/-90° in circumferential direction from the apex.

Statistical process control applied to mechanized peanut sowing as a function of soil texture

PubMed Central

Furlani, Carlos Eduardo Angeli; da Silva, Rouverson Pereira

2017-01-01

The successful establishment of agricultural crops depends on sowing quality, machinery performance, soil type and conditions, among other factors. This study evaluates the operational quality of mechanized peanut sowing in three soil types (sand, silt, and clay) with variable moisture contents. The experiment was conducted in three locations in the state of São Paulo, Brazil. The track-sampling scheme was used for 80 sampling locations of each soil type. Descriptive statistics and statistical process control (SPC) were used to evaluate the quality indicators of mechanized peanut sowing. The variables had normal distributions and were stable from the viewpoint of SPC. The best performance for peanut sowing density, normal spacing, and the initial seedling growing stand was found for clayey soil followed by sandy soil and then silty soil. Sandy or clayey soils displayed similar results regarding sowing depth, which was deeper than in the silty soil. Overall, the texture and the moisture of clayey soil provided the best operational performance for mechanized peanut sowing. PMID:28742095

Part A: Assessing the performance of the COMFA outdoor thermal comfort model on subjects performing physical activity

NASA Astrophysics Data System (ADS)

Kenny, Natasha A.; Warland, Jon S.; Brown, Robert D.; Gillespie, Terry G.

2009-09-01

This study assessed the performance of the COMFA outdoor thermal comfort model on subjects performing moderate to vigorous physical activity. Field tests were conducted on 27 subjects performing 30 min of steady-state activity (walking, running, and cycling) in an outdoor environment. The predicted COMFA budgets were compared to the actual thermal sensation (ATS) votes provided by participants during each 5-min interval. The results revealed a normal distribution in the subjects’ ATS votes, with 82% of votes received in categories 0 (neutral) to +2 (warm). The ATS votes were significantly dependent upon sex, air temperature, short and long-wave radiation, wind speed, and metabolic activity rate. There was a significant positive correlation between the ATS and predicted budgets (Spearman’s rho = 0.574, P < 0.01). However, the predicted budgets did not display a normal distribution, and the model produced erroneous estimates of the heat and moisture exchange between the human body and the ambient environment in 6% of the cases.

Gear Mesh Loss-of-Lubrication Experiments and Analytical Simulation

NASA Technical Reports Server (NTRS)

Handschuh, Robert F.; Polly, Joseph; Morales, Wilfredo

2011-01-01

An experimental program to determine the loss-of-lubrication (LOL) characteristics of spur gears in an aerospace simulation test facility has been completed. Tests were conducted using two different emergency lubricant types: (1) an oil mist system (two different misted lubricants) and (2) a grease injection system (two different grease types). Tests were conducted using a NASA Glenn test facility normally used for conducting contact fatigue. Tests were run at rotational speeds up to 10000 rpm using two different gear designs and two different gear materials. For the tests conducted using an air-oil misting system, a minimum lubricant injection rate was determined to permit the gear mesh to operate without failure for at least 1 hr. The tests allowed an elevated steady state temperature to be established. A basic 2-D heat transfer simulation has been developed to investigate temperatures of a simulated gear as a function of frictional behavior. The friction (heat generation source) between the meshing surfaces is related to the position in the meshing cycle, the load applied, and the amount of lubricant in the contact. Experimental conditions will be compared to those from the 2-D simulation.

Transient thermal analysis of a titanium multiwall thermal protection system

NASA Technical Reports Server (NTRS)

Blosser, M. L.

1982-01-01

The application of the SPAR thermal analyzer to the thermal analysis of a thermal protection system concept is discussed. The titanium multiwall thermal protection system concept consists of alternate flat and dimpled sheets which are joined together at the crests of the dimples and formed into 30 cm by 30 cm (12 in. by 12 in.) tiles. The tiles are mechanically attached to the structure. The complex tile geometry complicates thermal analysis. Three modes of heat transfer were considered: conduction through the gas inside the tile, conduction through the metal, and radiation between the various layers. The voids between the dimpled and flat sheets were designed to be small enough so that natural convection is insignificant (e.g., Grashof number 1000). A two step approach was used in the thermal analysis of the multiwall thermal protection system. First, an effective normal (through-the-thickness) thermal conductivity was obtained from a steady state analysis using a detailed SPAR finite element model of a small symmetric section of the multiwall tile. This effective conductivity was then used in simple one dimensional finite element models for preliminary analysis of several transient heat transfer problems.

Development of a nerve conduction technique for the recurrent laryngeal nerve.

PubMed

J Kim, Sang; G Lee, Dae; Kwon, Jeong-Yi

2014-12-01

To develop a reliable and safe laryngeal nerve conduction technique and to obtain consistent parameters as normal reference values. A prospective single-arm study. A nerve conduction test was performed on the contralateral normal side in 42 patients with unilateral vocal fold palsy. The recording was performed in the intact thyroarytenoid muscle using a monopolar needle. The electrical stimulation using a 37-mm monopolar needle was applied 3 cm below the lower margin of the cricoid cartilage, just lateral to the trachea and medial to the carotid artery, and its intensity was gradually increased until the amplitude of the electrical response reached the maximum level. The latency of the evoked muscle response was acquired at the first evoked waveform deflection from the baseline. The average latency of the recurrent laryngeal nerves was 1.98 ± 0.26 ms. The latencies showed normal distribution according to the quantile-quantile plot and Kolmogorov-Smirnov test (P = .098). There was no significant difference in latencies between the right and left recurrent laryngeal nerves. Anthropometric factors including height and weight did not show any correlation with the latencies. We developed a reliable and safe laryngeal nerve conduction technique and obtained normal reference values for the recurrent laryngeal nerve conduction study. This laryngeal nerve conduction study can be an additional tool for detecting recurrent laryngeal nerve injury if it is performed in combination with the conventional laryngeal electromyography. 4. © 2014 The American Laryngological, Rhinological and Otological Society, Inc.

Changes in nerve conduction and Pi/PCr ratio during denervation-reinnervation of the gastrocsoleus muscles of rats

NASA Technical Reports Server (NTRS)

Lai, K. S.; Jaweed, M. M.; Seestead, R.; Herbison, G. J.; Ditunno, J. F. Jr; McCully, K.; Chance, B.

1992-01-01

The purpose of this investigation was to study the changes in nerve conduction and phosphate metabolites of the gastrocsoleus muscles of rats during denervation-reinnervation. Sixteen male Sprague-Dawley rats underwent unilateral crush-denervation of the left sciatic nerves at the sciatic notch. Six rats were used for measurement of motor conduction latency and action potential amplitude of the gastrocsoleus muscle by stimulating the sciatic nerve at one, two and eight weeks after nerve crush. The other ten rats were designated for evaluation of the ratio of inorganic phosphorous (Pi) to phosphocreatine (PCr) by a 31P-phosphoenergetic spectrometer at two weeks and eight weeks after nerve crush. None of the sciatic nerves showed conduction to the gastrocsoleus at one or two weeks after nerve crush. At eight weeks postcrush, the motor conduction latency returned to within normal limits, whereas the action potential amplitude was only 55% of the normal. For the eight-week period of study, the Pi/PCr ratio of the normal control muscles ranged between 0.09 +/- 0.02 and 0.11 +/- 0.02 (mean +/- SD). The denervated muscles showed an increase of Pi/PCr ratio by 54% at two weeks postcrush, compared to the respective contralateral control sides. The ratios returned to the normal value by eight weeks postcrush. In summary, these data suggested that the metabolic recovery of the crush-denervated muscle followed the same pattern as the parameters of nerve conduction.

Auditory Brainstem Response Thresholds to Air- and Bone-Conducted CE-Chirps in Neonates and Adults

ERIC Educational Resources Information Center

Cobb, Kensi M.; Stuart, Andrew

2016-01-01

Purpose The purpose of this study was to compare auditory brainstem response (ABR) thresholds to air- and bone-conducted CE-Chirps in neonates and adults. Method Thirty-two neonates with no physical or neurologic challenges and 20 adults with normal hearing participated. ABRs were acquired with a starting intensity of 30 dB normal hearing level…

Protection of Hardware: Powering Systems (Power Converter, Normal Conducting, and Superconducting Magnets)

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

Pfeffer, H.; Flora, B.; Wolff, D.

2016-01-01

Along with the protection of magnets and power converters, we have added a section on personnel protection because this is our highest priority in the design and operation of power systems. Thus, our topics are the protection of people, power converters, and magnet loads (protected from the powering equipment), including normal conducting magnets and superconducting magnets.

Theory of superconductivity in oxides. Final technical report

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

Anderson, P.W.

1988-05-18

Progress was made towards a final theory of high-Tc superconductivity. The key elements are the work on normal-state properties and the actual mechanism for Tc. With the understanding (ZA) of the large anisotropy and other transport properties in the normal state, the model is uniquely determined: one must have one version or another of a holon-spinon quantum-fluid state, which is not a normal Fermi liquid. And with the recognition (HWA) of the large-repulsion holon-holon interactions, the author has the first way of thinking quantitatively about the superconducting state. Work on the pure Heisenberg system, which is related but not necessarilymore » crucial to understanding the superconducting properties is described.« less

Coherence-enhanced phase-dependent dissipation in long SNS Josephson junctions: Revealing Andreev bound state dynamics

NASA Astrophysics Data System (ADS)

Dassonneville, B.; Murani, A.; Ferrier, M.; Guéron, S.; Bouchiat, H.

2018-05-01

One of the best known causes of dissipation in ac-driven quantum systems stems from photon absorption causing transitions between levels. Dissipation can also be caused by the retarded response to the time-dependent excitation, and in general gives insight into the system's relaxation times and mechanisms. Here we address the dissipation in a mesoscopic normal wire with superconducting contacts, that sustains a dissipationless supercurrent at zero frequency and that may therefore naively be expected to remain dissipationless at a frequency lower than the superconducting gap. We probe the high-frequency linear response of such a normal metal/superconductor (NS) ring to a time-dependent flux by coupling it to a highly sensitive multimode microwave resonator. Far from being the simple, dissipationless derivative of the supercurrent-versus-phase relation, the ring's ac susceptibility also displays a dissipative component whose phase dependence is a signature of the dynamical processes occurring within the Andreev spectrum. We show how dissipation is driven by the competition between two mechanisms. The first is the relaxation of the Andreev level distribution function, while the second corresponds to microwave-induced transitions within the spectrum. Depending on the relative strength of those contributions, dissipation can be maximal at π , a phase at which the proximity-induced minigap closes, or can be maximal near π /2 , a phase at which the dc supercurrent is maximal. We also find that the dissipative response paradoxically increases at low temperature and can even exceed the normal-state conductance. The results are successfully confronted with theoretical predictions of the Kubo linear response and time-dependent Usadel equations, derived from the Bogoliubov-de Gennes Hamiltonian describing the SNS junction. These experiments thus demonstrate the power of the ac susceptibility measurement of individual hybrid mesoscopic systems in probing in a controlled way the quantum dynamics of Andreev bound states. By spanning different physical regimes, our experiments provide unique access to inelastic scattering and spectroscopy of an isolated quantum coherent system, and reveal the associated relaxation times. This technique should be a tool of choice to investigate topological superconductivity and detect the topological protection of edge states.

Exercise training normalizes renal blood flow responses to acute hypoxia in experimental heart failure: role of the α1-adrenergic receptor.

PubMed

Pügge, Carolin; Mediratta, Jai; Marcus, Noah J; Schultz, Harold D; Schiller, Alicia M; Zucker, Irving H

2016-02-01

Recent data suggest that exercise training (ExT) is beneficial in chronic heart failure (CHF) because it improves autonomic and peripheral vascular function. In this study, we hypothesized that ExT in the CHF state ameliorates the renal vasoconstrictor responses to hypoxia and that this beneficial effect is mediated by changes in α1-adrenergic receptor activation. CHF was induced in rabbits. Renal blood flow (RBF) and renal vascular conductance (RVC) responses to 6 min of 5% isocapnic hypoxia were assessed in the conscious state in sedentary (SED) and ExT rabbits with CHF with and without α1-adrenergic blockade. α1-adrenergic receptor expression in the kidney cortex was also evaluated. A significant decline in baseline RBF and RVC and an exaggerated renal vasoconstriction during acute hypoxia occurred in CHF-SED rabbits compared with the prepaced state (P < 0.05). ExT diminished the decline in baseline RBF and RVC and restored changes during hypoxia to those of the prepaced state. α1-adrenergic blockade partially prevented the decline in RBF and RVC in CHF-SED rabbits and eliminated the differences in hypoxia responses between SED and ExT animals. Unilateral renal denervation (DnX) blocked the hypoxia-induced renal vasoconstriction in CHF-SED rabbits. α1-adrenergic protein in the renal cortex of animals with CHF was increased in SED animals and normalized after ExT. These data provide evidence that the acute decline in RBF during hypoxia is caused entirely by the renal nerves but is only partially mediated by α1-adrenergic receptors. Nonetheless, α1-adrenergic receptors play an important role in the beneficial effects of ExT in the kidney. Copyright © 2016 the American Physiological Society.

Comprehensive Study of Pr-Doped GdBa2Cu3O7 - y System

NASA Astrophysics Data System (ADS)

Yamani, Z.; Akhavan, M.

1997-09-01

An extensive study of the magnetic, electrical transport, and structural properties of the normal and superconducting states of Gd1 - xPrxBa2Cu3O7 - y (GdPr-123) is presented. Ceramic compounds have been synthesized by the solid state reaction technique, and characterized by XRD, SEM, TGA, and DT techniques. The parent compound GdBa2Cu3O7 - y (Gd-123) is a high-Tc superconductor and the endpoint compound, PrBa2Cu3O7 - y (Pr-123) is a magnetic insulator, both having the crystal structures isomorphic to the 123 phase structure. The superconducting transition temperature is reduced with increasing Pr content in a non-linear manner, in contrast to the Abrikosov-Gorkov pair breaking theory. A metal-insulator transition is observed at the critical Pr content, xcr 0.45, at which superconductivity completely disappears. Magnetic susceptibility measurements show that the nominal Pr valence is 3.86+, independent of the Pr content. The metal-insulator transition in this system is similar to that in the oxygen-deficient RBa2Cu3O7 - y (R-123) system. Based on this resemblance, we suggest that Pr doping reduces the carrier concentration (either by hole filling/localization or changes in the band structure) similar to the deoxygenated case. Hence, the environment surrounding the Cu-O layers is important to high-Tc superconductivity (HTSC). In this sense, HTSC cannot completely be two dimensional feature. A chain-plane correlation (CPC) effect is plausible. The normal state conduction mechanism has been interpreted by the quantum percolation theory based on localized states. Localization is probably caused by the Pr valence fluctuations in the GdPr-123 system.

Monophasic action potentials of right atrium and electrophysiological properties of AV conducting system in patients with hypothyroidism.

PubMed Central

Gavrilescu, S; Luca, C; Streian, C; Lungu, G; Deutsch, G

1976-01-01

In 12 patients with manifest hypothyroidism right atrial monophasic action potentials showed a significant prolongation in comparison with data from normal or euthyroid patients. Atrial effective refractory periods were also significantly prolonged. After thyroid treatment the monophasic action potential duration and the effective refractory period of the right atrium were within normal ranges. In 6 hypothyroid patients studies of AV conduction with the aid of His bundle electrography and atrial pacing showed a supraHisian conduction delay which was manifest in one case and latent in another two. InfraHisian conduction delay was encountered in 2 cases. PMID:1008978

Regulation of hepatic ABCC transporters by xenobiotics and in disease states

PubMed Central

Gu, Xinsheng; Manautou, Jose E.

2015-01-01

The subfamily of ABCC transporters consists of 13 members in mammals, including the multidrug resistance-associated proteins (MRPs), sulfonylurea receptors (SURs), and the cystic fibrosis transmembrane conductance regulator (CFTR). These proteins play roles in chemical detoxification, disposition, and normal cell physiology. ABCC transporters are expressed differentially in the liver and are regulated at the transcription and translation level. Their expression and function are also controlled by post-translational modification and membrane-trafficking events. These processes are tightly regulated. Information about alterations in the expression of hepatobiliary ABCC transporters could provide important insights into the pathogenesis of diseases and disposition of xenobiotics. In this review, we describe the regulation of hepatic ABCC transporters in humans and rodents by a variety of xenobiotics, under disease states and in genetically modified animal models deficient in transcription factors, transporters, and cell-signaling molecules. PMID:20233023

Non-Fermi-liquid nature and exotic thermoelectric power in the heavy-fermion superconductor UBe13

NASA Astrophysics Data System (ADS)

Shimizu, Yusei; Pourret, Alexandre; Knebel, Georg; Palacio-Morales, Alexandra; Aoki, Dai

2015-12-01

We report quite exotic thermoelectric power S in UBe13. At 0 T, the negative S /T continues to strongly enhance down to the superconducting transition temperature with no Fermi-liquid behavior. |S /T | is dramatically suppressed and becomes rather modest with increasing field. We have also obtained precise field dependencies of (i) an anomaly in S due to an exotic Kondo effect and (ii) a field-induced anomaly in S /T associated with the anomalous upward Hc 2(T ) . In contrast to the field-sensitive transport property, the normal-state specific heat is magnetically robust, indicating that the largeness of the 5 f density of states remains in high fields. This unusual behavior in UBe13 can be explained by a considerable change in the energy derivative of the conduction-electron lifetime τc(ɛ ) at the Fermi level under magnetic fields.

Study of cost/benefit tradeoffs for reducing the energy consumption of the commercial air transportation system

NASA Technical Reports Server (NTRS)

Coykendall, R. E.; Curry, J. K.; Domke, A. E.; Madsen, S. E.

1976-01-01

Economic studies were conducted for three general fuel conserving options: (1) improving fuel consumption characteristics of existing aircraft via retrofit modifications; (2) introducing fuel efficient derivations of existing production aircraft and/or introducing fuel efficient, current state-of-the-art new aircraft; and (3) introducing an advanced state-of-the-art turboprop airplane. These studies were designed to produce an optimum airline fleet mix for the years 1980, 1985 and 1990. The fleet selected accommodated a normal growth market by introducing somewhat larger aircraft while solving for maximum departure frequencies and a minimum load factor corresponding to a 15% investment hurdle rate. Fuel burnt per available-seat-mile flown would drop 22% from 1980 to 1990 due to the use of more fuel efficient aircraft designs, larger average aircraft size, and increased seating density. An inflight survey was taken to determine air traveler attitudes towards a new generation of advanced turboprops.

Edge currents shunt the insulating bulk in gapped graphene

NASA Astrophysics Data System (ADS)

Zhu, M. J.; Kretinin, A. V.; Thompson, M. D.; Bandurin, D. A.; Hu, S.; Yu, G. L.; Birkbeck, J.; Mishchenko, A.; Vera-Marun, I. J.; Watanabe, K.; Taniguchi, T.; Polini, M.; Prance, J. R.; Novoselov, K. S.; Geim, A. K.; Ben Shalom, M.

2017-02-01

An energy gap can be opened in the spectrum of graphene reaching values as large as 0.2 eV in the case of bilayers. However, such gaps rarely lead to the highly insulating state expected at low temperatures. This long-standing puzzle is usually explained by charge inhomogeneity. Here we revisit the issue by investigating proximity-induced superconductivity in gapped graphene and comparing normal-state measurements in the Hall bar and Corbino geometries. We find that the supercurrent at the charge neutrality point in gapped graphene propagates along narrow channels near the edges. This observation is corroborated by using the edgeless Corbino geometry in which case resistivity at the neutrality point increases exponentially with increasing the gap, as expected for an ordinary semiconductor. In contrast, resistivity in the Hall bar geometry saturates to values of about a few resistance quanta. We attribute the metallic-like edge conductance to a nontrivial topology of gapped Dirac spectra.

Effect of spin fluctuations on the electronic structure in iron-based superconductors

NASA Astrophysics Data System (ADS)

Heimes, Andreas; Grein, Roland; Eschrig, Matthias

2012-08-01

Magnetic inelastic neutron scattering studies of iron-based superconductors reveal a strongly temperature-dependent spin-fluctuation spectrum in the normal conducting state, which develops a prominent low-energy resonance feature when entering the superconducting state. Angle-resolved photoemission spectroscopy (ARPES) and scanning tunneling spectroscopy (STS) allow us to study the fingerprints of fluctuation modes via their interactions with electronic quasiparticles. We calculate such fingerprints in 122 iron pnictides using an experimentally motivated spin-fluctuation spectrum and make a number of predictions that can be tested in ARPES and STS experiments. This includes discussions of the quasiparticle scattering rate and the superconducting order parameter. In quantitative agreement with experiment we reproduce the quasiparticle dispersions obtained from momentum distribution curves as well as energy distribution curves. We discuss the relevance of the coupling between spin fluctuations and electronic excitations for the superconducting mechanism.

Possible mechanism to enhance spin-fluctuation-mediated superconductivity in two-dimensional organic conductor

NASA Astrophysics Data System (ADS)

Nonoyama, Yoshito; Maekawa, Yukiko; Kobayashi, Akito; Suzumura, Yoshikazu; Yamada, Jun-ichi

2008-10-01

Mechanisms of superconductivity in quasi-two-dimensional organic conductors have been investigated using an extended Hubbard model by using the transfer energies between BDA-TTP molecules for β-(BDA-TTP)2I3 based on the X-ray experiment data and the extended Hückel calculation. We obtain several mean-field solutions with charge orderings which may represent short-range orderings or low-energy fluctuations in the low-dimensional electronic system. In the pressure-temperature phase diagram, a charge ordered metal state almost degenerates with a normal metal state between an insulating phase with charge ordering and the normal metal phase. Using the random phase approximation (RPA) and the linearized gap equation, the transition temperature of the superconducting state is estimated for the charge-ordered metal state and the normal metal state. It is found that transition temperature of the superconductivity induced by spin fluctuations in the charge-ordered metal state is much higher than that of the normal metal state and that the superconductivity in the charge-ordered metal state is the gapless d-wave. This suggests that the short range charge ordering may also contribute to an enhancement of spin-fluctuation-mediated superconductivity. The difference in the superconducting states between β-(BDA-TTP)2I3 and β-(BDA-TTP)2SbF6 are briefly discussed.

Molecular Tagging Velocimetry Development for In-situ Measurement in High-Temperature Test Facility

NASA Technical Reports Server (NTRS)

Andre, Matthieu A.; Bardet, Philippe M.; Burns, Ross A.; Danehy, Paul M.

2015-01-01

The High Temperature Test Facility, HTTF, at Oregon State University (OSU) is an integral-effect test facility designed to model the behavior of a Very High Temperature Gas Reactor (VHTR) during a Depressurized Conduction Cooldown (DCC) event. It also has the ability to conduct limited investigations into the progression of a Pressurized Conduction Cooldown (PCC) event in addition to phenomena occurring during normal operations. Both of these phenomena will be studied with in-situ velocity field measurements. Experimental measurements of velocity are critical to provide proper boundary conditions to validate CFD codes, as well as developing correlations for system level codes, such as RELAP5 (http://www4vip.inl.gov/relap5/). Such data will be the first acquired in the HTTF and will introduce a diagnostic with numerous other applications to the field of nuclear thermal hydraulics. A laser-based optical diagnostic under development at The George Washington University (GWU) is presented; the technique is demonstrated with velocity data obtained in ambient temperature air, and adaptation to high-pressure, high-temperature flow is discussed.

Electrical Conductivity through a Single Atomic Step Measured with the Proximity-Induced Superconducting Pair Correlation

DOE PAGES

Kim, Howon; Lin, Shi -Zeng; Graf, Matthias J.; ...

2016-09-08

Local disordered nanostructures in an atomically thick metallic layer on a semiconducting substrate play significant and decisive roles in transport properties of two-dimensional (2D) conductive systems. We measured the electrical conductivity through a step of monoatomic height in a truly microscopic manner by using as a signal the superconducting pair correlation induced by the proximity effect. The transport property across a step of a one-monolayer Pb surface metallic phase, formed on a Si(111) substrate, was evaluated by inducing the pair correlation around the local defect and measuring its response, i.e., the reduced density of states at the Fermi energy usingmore » scanning tunneling microscopy. We found that the step resistance has a significant contribution to the total resistance on a nominally flat surface. Our study also revealed that steps in the 2D metallic layer terminate the propagation of the pair correlation. Furthermore, superconductivity is enhanced between the first surface step and the superconductor–normal-metal interface by reflectionless tunneling when the step is located within a coherence length.« less

Electrical Conductivity through a Single Atomic Step Measured with the Proximity-Induced Superconducting Pair Correlation.

PubMed

Kim, Howon; Lin, Shi-Zeng; Graf, Matthias J; Miyata, Yoshinori; Nagai, Yuki; Kato, Takeo; Hasegawa, Yukio

2016-09-09

Local disordered nanostructures in an atomically thick metallic layer on a semiconducting substrate play significant and decisive roles in transport properties of two-dimensional (2D) conductive systems. We measured the electrical conductivity through a step of monoatomic height in a truly microscopic manner by using as a signal the superconducting pair correlation induced by the proximity effect. The transport property across a step of a one-monolayer Pb surface metallic phase, formed on a Si(111) substrate, was evaluated by inducing the pair correlation around the local defect and measuring its response, i.e., the reduced density of states at the Fermi energy using scanning tunneling microscopy. We found that the step resistance has a significant contribution to the total resistance on a nominally flat surface. Our study also revealed that steps in the 2D metallic layer terminate the propagation of the pair correlation. Superconductivity is enhanced between the first surface step and the superconductor-normal-metal interface by reflectionless tunneling when the step is located within a coherence length.

Thermoelectric properties of FeAs based superconductors, with thick perovskite- and Sm-O fluorite-type blocking layers

NASA Astrophysics Data System (ADS)

Singh, S. J.; Shimoyama, J.; Ogino, H.; Kishio, K.

2015-11-01

The transport properties (electrical resistivity, Hall and Seebeck coefficient, and thermal conductivity) of iron based superconductors with thick perovskite-type oxide blocking layers and fluorine-doped SmFeAsO were studied to explore their possible potential for thermoelectric applications. The thermal conductivity of former compounds depicts the dominated role of phonon and its value decreases rapidly below the Tc, suggesting the addition of scattering of phonons. Both the Seebeck coefficient (S) and Hall coefficient (RH) of all samples were negative in the whole temperature region below 300 K, indicating that the major contribution to the normal state conductivity is by electrons. In addition, the profile of S(T) and RH(T) of all samples have similar behaviours as would be expected for a multi-band superconductors. Although the estimated thermoelectric figure of merit (ZT) of these compounds was much lower than that of practically applicable thermoelectric materials, however its improvement can be expected by optimizing microstructure of the polycrystalline materials, such as densification and grain orientation.

Superconducting fault current-limiter with variable shunt impedance

DOEpatents

Llambes, Juan Carlos H; Xiong, Xuming

2013-11-19

A superconducting fault current-limiter is provided, including a superconducting element configured to resistively or inductively limit a fault current, and one or more variable-impedance shunts electrically coupled in parallel with the superconducting element. The variable-impedance shunt(s) is configured to present a first impedance during a superconducting state of the superconducting element and a second impedance during a normal resistive state of the superconducting element. The superconducting element transitions from the superconducting state to the normal resistive state responsive to the fault current, and responsive thereto, the variable-impedance shunt(s) transitions from the first to the second impedance. The second impedance of the variable-impedance shunt(s) is a lower impedance than the first impedance, which facilitates current flow through the variable-impedance shunt(s) during a recovery transition of the superconducting element from the normal resistive state to the superconducting state, and thus, facilitates recovery of the superconducting element under load.

Gating of the late Na+ channel in normal and failing human myocardium.

PubMed

Undrovinas, Albertas I; Maltsev, Victor A; Kyle, John W; Silverman, Norman; Sabbah, Hani N

2002-11-01

We previously reported an ultraslow inactivating late Na+ current (INaL) in left ventricular cardiomyocytes (VC) isolated from normal (NVC) and failing (FVC) human hearts. This current could play a role in heart failure-induced repolarization abnormalities. To identify properties of NaCh contributing to INaL, we examined early and late openings in cell-attached patches of HEK293 cells expressing human cardiac NaCh alpha-subunit (alpha-HEK) and in VC of one normal and three failing human hearts. Two types of the late NaCh openings underlay INaL in all three preparations: scattered late (SLO) and bursts (BO). Amplitude analysis revealed that slope conductance for both SLO and BO was the same compared to the main level of early openings (EO) in both VC (21 vs 22.7pS, NVC; 22.7 vs 22.6pS, FVC) and alpha-HEK (23.2 vs 23pS), respectively. Analysis of SLO latencies revealed voltage-independent ultraslow inactivation in all preparations with tendency to be slower in FVC compared to NCV. EO and SLO render one open voltage-independent state (tau approximately 0.4ms) for NVC and FVC. One open (voltage-dependent) and two closed states (one voltage-dependent and another voltage-independent) were found in BO of both specimens. Burst duration tend to be longer in FVC ( approximately 50ms) than in NVC ( approximately 30ms). In FVC we found both modes SLO and BO at membrane potential of -10mV that is attribute for take-off voltages (from -18 to -2mV) for early afterdepolarizations (EAD's) in FVC. In conclusions, we found a novel gating mode SLO that manifest slow (hundreds of ms), voltage-independent inactivation in both NVC and FVC. We were unable to reliably demonstrate any differences in the properties of the late NaCh in failing vs a normal human heart. Accordingly, the late current appears to be generated by a single population of channels in normal and failing human ventricular myocardium. Both SLO and BO could be implicated in EADs in HF.

The movement and deposition of PM2.5 in the upper respiratory tract for the patients with heart failure: an elementary CFD study.

PubMed

Zhang, Tiantian; Gao, Bin; Zhou, Zhixiang; Chang, Yu

2016-12-28

PM2.5 is an important factor to affect the patients with respiratory and cardiovascular diseases. Clinical studies have found that the morbidity and mortality of patients with heart failure (HF) have a close relationship with the movement and deposition state of PM2.5. One reason is that the breathing pattern of patients with HF has obvious difference with healthy people, however the effect caused by these differences on the distribution regularity of PM2.5 in the respiratory tract is still unclear. Hence, a computational fluid dynamics simulation was conducted to clarify the aerodynamic effect of breathing pattern of patients with HF on respiratory system. Ideal upper respiratory tract geometric model was established based on standardized aerosol research laboratory of Alberta and Weibel A dimension. The discrete phase method is used to calculate the movement of the airflow and particles. The flow rate were chosen as the inlet boundary conditions, and the outlets are set at a constant pressure. The rate of particle deposition, distribution location, wall pressure, flow velocity and wall shear stress are obtained, and compared to the normal control. The results demonstrated that the rate of escaped particles in every bronchial outlet of the patients with HF was more than the normal controls, meanwhile the trapped was less (1024 < 1160). There was higher by 12.9% possibility that the PM2.5 entered the lungs than the normal control. The aerodynamic performances of HF patients are different from normal control. Compared to the normal control, under similar environment, there is higher possibility of PM2.5 moving into lungs, and these particles could affect the function of the respiratory system, resulting in the deterioration of the state of cardiovascular system. In short, it's necessary to pay more attention to the living environment of HF patients, to reduce the content of PM2.5 particles in the air, and reduce the damage of PM2.5 particles caused by breathing patterns.

[Association between time of permanence at early education program (Estancias Infantiles) and developmental level for children in situation of poverty].

PubMed

Rizzoli-Córdoba, Antonio; Vargas-Carrillo, Laura Ibernia; Vásquez-Ríos, Jorge Rodrigo; Reyes-Morales, Hortensia; Villasís-Keever, Miguel Ángel; O'Shea-Cuevas, Gabriel; Aceves-Villagrán, Daniel; Muñoz-Hernández, Onofre; García-Aranda, José Alberto

Early education program (EEP) was created to support parents with 1 to 3 year olds living in poverty situation in Mexico, and includes education and child daycare for 8h five days per week. The objective of this study was to evaluate the association between length of stay in EEP and the level of development in children. Cross sectional, population-based study conducted in two Mexican states. All children aged between 12 to 48 months enrolled in EEP from November 2014 to January 2015 were included. Child Development Evaluation (CDE) test was used to screen early development in every child. Normal early development prevalence odds ratio (OR) was calculated adjusted by gender, impairment and state, using as a reference those children with less than 30 days in the program. The study included 3,387 children from 177 EEP nurseries, from which 53% were male; age by group was divided in 12-24 months (22.3%), 25-36 months (37.6%) and 37-42 months (40.1%). Normal development adjusted OR by age was 1.9 (CI95%: 1.30-2.78) for 6-11 months, 2.36 (CI95%: 1.60-3.50) for 12-17 months, 2.78 (CI95%: 1.65-4.65) for 18-23 months and 3.46 (CI95%: 2.13-5.60) for >24 months. By area of development, a greater probability of having a normal result for language and social areas was observed after 6 months in the program, and for motor (both gross and fine) and knowledge areas after 12 months. The length of the stay in the EEP after 6 months significantly and progressively increases the probability of normal development regardless of gender and age. Copyright © 2017 Hospital Infantil de México Federico Gómez. Publicado por Masson Doyma México S.A. All rights reserved.

Observation of cyclotron resonance and electron-phonon coupling in surface states of the bulk-insulating topological insulator Cu 0.02Bi 2Se 3

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

Wu, Liang; Tse, Wang-Kong; Morris, C. M.

2015-02-05

We have utilized magneto-optical time-domain spectroscopy to investigate the low frequency optical response of topological insulator Cu 0.02Bi 2Se 3 and Bi 2Se 3 films. With both field and frequency depedence, such experiments give sufficient information to measure the mobility and carrier density of multiple conduction channels simultaneously. We observe sharp cyclotron resonances (CRs) in both samples. The small amount of Cu substitution into the Cu 0.02Bi 2Se 3 induces a true bulk insulator with only a single conduction channel with total sheet carrier density 4.9 x 10 12/cm 2 and mobility as large as 4000 cm 2/V s. Thismore » is consistent with pure topological surface state (TSSs) conduction with a chemical potential 150 meV above the Dirac point. Hence, a true topological insulator with an insulating bulk is realized. The CR broadens at high fields, an e ect that we attribute to an electron-phonon interaction. This assignment is supported by an extended Drude model analysis on the zero field data. In contrast to Cu 0.02Bi 2Se 3, two charge channels were observed in normal Bi 2Se 3 films. We demonstrate a method to distinguish between the dominant TSSs and trivial bulk/2DEG states. The dominant channel exhibits a CR with a carrier density of ~2.0 x 10 13/cm 2 and mobility ~3200 cm 2/V s, consistent with TSSs with a chemical potential ~350meV above the Dirac point.« less

electric dipole superconductor in bilayer exciton system

NASA Astrophysics Data System (ADS)

Sun, Qing-Feng; Jiang, Qing-Dong; Bao, Zhi-Qiang; Xie, X. C.

Recently, it was reported that the bilayer exciton systems could exhibit many new phenomena, including the large bilayer counterflow conductivity, the Coulomb drag, etc. These phenomena imply the formation of exciton condensate superfluid state. On the other hand, it is now well known that the superconductor is the condensate superfluid state of the Cooper pairs, which can be viewed as electric monopoles. In other words, the superconductor state is the electric monopole condensate superfluid state. Thus, one may wonder whether there exists electric dipole superfluid state. In this talk, we point out that the exciton in a bilayer system can be considered as a charge neutral electric dipole. And we derive the London-type and Ginzburg-Landau-type equations of electric dipole superconductivity. From these equations, we discover the Meissner-type effect (against spatial variation of magnetic fields), and the dipole current Josephson effect. The frequency in the AC Josephson effect of the dipole current is equal to that in the normal (monopole) superconductor. These results can provide direct evidence for the formation of exciton superfluid state in the bilayer systems and pave new ways to obtain the electric dipole current. We gratefully acknowledge the financial support by NBRP of China (2012CB921303 and 2015CB921102) and NSF-China under Grants Nos. 11274364 and 11574007.

Safety of the HyperSound® Audio System in Subjects with Normal Hearing.

PubMed

Mehta, Ritvik P; Mattson, Sara L; Kappus, Brian A; Seitzman, Robin L

2015-06-11

The objective of the study was to assess the safety of the HyperSound® Audio System (HSS), a novel audio system using ultrasound technology, in normal hearing subjects under normal use conditions; we considered pre-exposure and post-exposure test design. We investigated primary and secondary outcome measures: i) temporary threshold shift (TTS), defined as >10 dB shift in pure tone air conduction thresholds and/or a decrement in distortion product otoacoustic emissions (DPOAEs) >10 dB at two or more frequencies; ii) presence of new-onset otologic symptoms after exposure. Twenty adult subjects with normal hearing underwent a pre-exposure assessment (pure tone air conduction audiometry, tympanometry, DPOAEs and otologic symptoms questionnaire) followed by exposure to a 2-h movie with sound delivered through the HSS emitter followed by a post-exposure assessment. No TTS or new-onset otological symptoms were identified. HSS demonstrates excellent safety in normal hearing subjects under normal use conditions.

Safety of the HyperSound® Audio System in Subjects with Normal Hearing

PubMed Central

Mattson, Sara L.; Kappus, Brian A.; Seitzman, Robin L.

2015-01-01

The objective of the study was to assess the safety of the HyperSound® Audio System (HSS), a novel audio system using ultrasound technology, in normal hearing subjects under normal use conditions; we considered pre-exposure and post-exposure test design. We investigated primary and secondary outcome measures: i) temporary threshold shift (TTS), defined as >10 dB shift in pure tone air conduction thresholds and/or a decrement in distortion product otoacoustic emissions (DPOAEs) >10 dB at two or more frequencies; ii) presence of new-onset otologic symptoms after exposure. Twenty adult subjects with normal hearing underwent a pre-exposure assessment (pure tone air conduction audiometry, tympanometry, DPOAEs and otologic symptoms questionnaire) followed by exposure to a 2-h movie with sound delivered through the HSS emitter followed by a post-exposure assessment. No TTS or new-onset otological symptoms were identified. HSS demonstrates excellent safety in normal hearing subjects under normal use conditions. PMID:26779330

Evaluation of Bias-Variance Trade-Off for Commonly Used Post-Summarizing Normalization Procedures in Large-Scale Gene Expression Studies

PubMed Central

Qiu, Xing; Hu, Rui; Wu, Zhixin

2014-01-01

Normalization procedures are widely used in high-throughput genomic data analyses to remove various technological noise and variations. They are known to have profound impact to the subsequent gene differential expression analysis. Although there has been some research in evaluating different normalization procedures, few attempts have been made to systematically evaluate the gene detection performances of normalization procedures from the bias-variance trade-off point of view, especially with strong gene differentiation effects and large sample size. In this paper, we conduct a thorough study to evaluate the effects of normalization procedures combined with several commonly used statistical tests and MTPs under different configurations of effect size and sample size. We conduct theoretical evaluation based on a random effect model, as well as simulation and biological data analyses to verify the results. Based on our findings, we provide some practical guidance for selecting a suitable normalization procedure under different scenarios. PMID:24941114

Trajectories of health-related quality of life during the natural history of dementia: a six-wave longitudinal study.

PubMed

Yu, Hongmei; Gao, Caihong; Zhang, Yanbo; He, Runlian; Zhou, Liye; Liang, Ruifeng

2017-09-01

The objective of this study was to explore profiles of quality of life (QoL) trajectories during the natural history of dementia and individual variations contributing to QoL trajectories. We conducted a longitudinal community-based study of 520 elderly people with mild cognitive impairment and 100 healthy people aged 60 years or over. We conducted six waves of assessment between October 2010 and May 2013 in Taiyuan, mainland China. Cognitively normal, mild cognitive impairment, global impairment, and Alzheimer's disease (AD) were defined as state 1, 2, 3, and 4, respectively. We assessed health-related QoL (HRQoL) via the Quality of Life-Alzheimer's Disease (QoL-AD) Chinese version. We used the latent growth curve model (LGCM) to investigate change in HRQoL over time. Latent growth curve model analysis revealed a mean initial QoL level of 29.865 with substantial variation and a significant mean slope for the whole sample. Multigroup LGCM showed substantial variations across individuals in initial QoL levels for each cognitive state transition group. For the slope factor, we found significant changes and variations for the transition from state 2 to 3 and from state 3 to 4. We estimated mean QoL levels over six assessments based on intercept, slope, and factor loadings for the whole sample and the three cognitive state transition groups. A decline in subjective QoL is not inevitable during the natural history of dementia in community settings, and there is a degree of individual variation in QoL. Future studies should investigate the factors associated with individual variations in QoL trajectories in AD. Copyright © 2016 John Wiley & Sons, Ltd.

Fault Wear and Friction Evolution: Experimental Analysis

NASA Astrophysics Data System (ADS)

Boneh, Y.; Chang, J. C.; Lockner, D. A.; Reches, Z.

2011-12-01

Wear is an inevitable product of frictional sliding of brittle rocks as evidenced by the ubiquitous occurrence of fault gouge and slickenside striations. We present here experimental observations designed to demonstrate the relationship between wear and friction and their governing mechanisms. The experiments were conducted with a rotary shear apparatus on solid, ring-shaped rock samples that slipped for displacements up to tens of meters. Stresses, wear and temperature were continuously monitored. We analyzed 86 experiments of Kasota dolomite, Sierra White granite, Pennsylvania quartzite, Karoo gabbro, and Tennessee sandstone at slip velocities ranging from 0.002 to 0.97 m/s, and normal stress from 0.25 to 6.9 MPa. We conducted two types of runs: short slip experiments (slip distance < 25 mm) primarily on fresh, surface-ground samples, designed to analyze initial wear mechanisms; and long slip experiments (slip distance > 3 m) designed to achieve mature wear conditions and to observe the evolution of wear and friction as the fault surfaces evolved. The experiments reveal three wear stages: initial, running-in, and steady-state. The initial stage is characterized by (1) discrete damage striations, the length of which is comparable to total slip , and local pits or plow features; (2) timing and magnitude of fault-normal dilation corresponds to transient changes of normal and shear stresses; and (3) surface roughness increasing with the applied normal stress. We interpret these observations as wear mechanisms of (a) plowing into the fresh rock surfaces; (b) asperity breakage; and (c) asperity climb. The running-in stage is characterized by (1) intense wear-rate over a critical wear distance of Rd = 0.3-2 m; (2) drop of friction coefficient over a weakening distance of Dc = 0.2-4 m; (3) Rd and Dc display positive, quasi-linear relation with each other. We interpret these observations as indicating the organizing of newly-created wear particles into a 'three-body' structure that acts to lubricate the fault (Reches & Lockner, 2010). The steady-state stage is characterized by (1) relatively low wear-rate (approximately 10% of running-in wear-rate) and (2) quasi-constant friction coefficient. These observations suggest only small changes in the gouge layer in term of thickness (100 to 200 microns) and strength in this final stage. The present study indicates that (1) wear by plowing and asperity failure initiate early, during the first few millimeters of slip; and (2) wear and associated gouge formation appear as the controlling factors of friction evolution and fault weakening.

Fast electron transfer through a single molecule natively structured redox protein

NASA Astrophysics Data System (ADS)

Della Pia, Eduardo Antonio; Chi, Qijin; MacDonald, J. Emyr; Ulstrup, Jens; Jones, D. Dafydd; Elliott, Martin

2012-10-01

The electron transfer properties of proteins are normally measured as molecularly averaged ensembles. Through these and related measurements, proteins are widely regarded as macroscopically insulating materials. Using scanning tunnelling microscopy (STM), we present new measurements of the conductance through single-molecules of the electron transfer protein cytochrome b562 in its native conformation, under pseudo-physiological conditions. This is achieved by thiol (SH) linker pairs at opposite ends of the molecule through protein engineering, resulting in defined covalent contact between a gold surface and a platinum-iridium STM tip. Two different orientations of the linkers were examined: a long-axis configuration (SH-LA) and a short-axis configuration (SH-SA). In each case, the molecular conductance could be `gated' through electrochemical control of the heme redox state. Reproducible and remarkably high conductance was observed in this relatively complex electron transfer system, with single-molecule conductance values peaking around 18 nS and 12 nS for the SH-SA and SH-LA cytochrome b562 molecules near zero electrochemical overpotential. This strongly points to the important role of the heme co-factor bound to the natively structured protein. We suggest that the two-step model of protein electron transfer in the STM geometry requires a multi-electron transfer to explain such a high conductance. The model also yields a low value for the reorganisation energy, implying that solvent reorganisation is largely absent.The electron transfer properties of proteins are normally measured as molecularly averaged ensembles. Through these and related measurements, proteins are widely regarded as macroscopically insulating materials. Using scanning tunnelling microscopy (STM), we present new measurements of the conductance through single-molecules of the electron transfer protein cytochrome b562 in its native conformation, under pseudo-physiological conditions. This is achieved by thiol (SH) linker pairs at opposite ends of the molecule through protein engineering, resulting in defined covalent contact between a gold surface and a platinum-iridium STM tip. Two different orientations of the linkers were examined: a long-axis configuration (SH-LA) and a short-axis configuration (SH-SA). In each case, the molecular conductance could be `gated' through electrochemical control of the heme redox state. Reproducible and remarkably high conductance was observed in this relatively complex electron transfer system, with single-molecule conductance values peaking around 18 nS and 12 nS for the SH-SA and SH-LA cytochrome b562 molecules near zero electrochemical overpotential. This strongly points to the important role of the heme co-factor bound to the natively structured protein. We suggest that the two-step model of protein electron transfer in the STM geometry requires a multi-electron transfer to explain such a high conductance. The model also yields a low value for the reorganisation energy, implying that solvent reorganisation is largely absent. Electronic supplementary information (ESI) available: Experimental methods, DNA and protein sequences, additional STM statistical analysis and images, electrochemical data and It-z data analysis. See DOI: 10.1039/c2nr32131a

Does Epileptiform Activity Represent a Failure of Neuromodulation to Control Central Pattern Generator-Like Neocortical Behavior?

PubMed Central

Traub, Roger D.; Whittington, Miles A.; Hall, Stephen P.

2017-01-01

Rhythmic motor patterns in invertebrates are often driven by specialized “central pattern generators” (CPGs), containing small numbers of neurons, which are likely to be “identifiable” in one individual compared with another. The dynamics of any particular CPG lies under the control of modulatory substances, amines, or peptides, entering the CPG from outside it, or released by internal constituent neurons; consequently, a particular CPG can generate a given rhythm at different frequencies and amplitudes, and perhaps even generate a repertoire of distinctive patterns. The mechanisms exploited by neuromodulators in this respect are manifold: Intrinsic conductances (e.g., calcium, potassium channels), conductance state of postsynaptic receptors, degree of plasticity, and magnitude and kinetics of transmitter release can all be affected. The CPG concept has been generalized to vertebrate motor pattern generating circuits (e.g., for locomotion), which may contain large numbers of neurons – a construct that is sensible, if there is enough redundancy: that is, the large number of neurons consists of only a small number of classes, and the cells within any one class act stereotypically. Here we suggest that CPG and modulator ideas may also help to understand cortical oscillations, normal ones, and particularly transition to epileptiform pathology. Furthermore, in the case illustrated, the mechanism of the transition appears to be an exaggerated form of a normal modulatory action used to influence sensory processing. PMID:29093667

Numerical Simulation of the Combustion of Fuel Droplets: Finite Rate Kinetics and Flame Zone Grid Adaptation (CEFD)

NASA Technical Reports Server (NTRS)

Gogos, George; Bowen, Brent D.; Nickerson, Jocelyn S.

2002-01-01

The NASA Nebraska Space Grant (NSGC) & EPSCoR programs have continued their effort to support outstanding research endeavors by funding the Numerical Simulation of the Combustion of Fuel Droplets study at the University of Nebraska at Lincoln (UNL). This team of researchers has developed a transient numerical model to study the combustion of suspended and moving droplets. The engines that propel missiles, jets, and many other devices are dependent upon combustion. Therefore, data concerning the combustion of fuel droplets is of immediate relevance to aviation and aeronautical personnel, especially those involved in flight operations. The experiments being conducted by Dr. Gogos and Dr. Nayagam s research teams, allow investigators to gather data for comparison with theoretical predictions of burning rates, flame structures, and extinction conditions. The consequent improved hndamental understanding droplet combustion may contribute to the clean and safe utilization of fossil hels (Williams, Dryer, Haggard & Nayagam, 1997, 72). The present state of knowledge on convective extinction of he1 droplets derives fiom experiments conducted under normal gravity conditions. However, any data obtained with suspended droplets under normal gravity are grossly affected by gravity. The need to obtain experimental data under microgravity conditions is therefore well justified and addresses one of the goals of NASA s Human Exploration and Development of Space (HEDS) microgravity combustion experiment.

Morphometric and molecular analyses of the sand fly species Lutzomyia shannoni (Diptera: Psychodidae: Phlebotominae) collected from seven different geographical areas in the southeastern United States.

PubMed

Florin, David A; Davies, Stephen J; Olsen, Cara; Lawyer, Phillip; Lipnick, Robert; Schultz, George; Rowton, Edgar; Wilkerson, Richard; Keep, Lisa

2011-03-01

A morphometric and molecular study of adult male and female Lutzomyia shannoni (Dyar 1929) collected at seven different locations within the southeastern United States was conducted to assess the degree of divergence between the grouped specimens from each location. The collection locations were as follows: Fort Bragg, NC; Fort Campbell, KY; Fort Rucker, AL; Ossabaw Island, GA; Patuxent National Wildlife Research Refuge, MD; Suwannee National Wildlife Refuge, FL; and Baton Rouge, LA. Forty males and forty females from each location were analyzed morphometrically from 54 and 49 character measurements, respectively. In addition, the molecular markers consisting of the partial cytochrome c oxidase subunit I (from 105 sand flies: 15 specimens/collection site) and the partial internal transcribed spacer 2 (from 42 sand flies: six specimens/collection site) were compared. Multivariate analyses indicate that the low degree of variation between the grouped specimens from each collection site prevents the separation of any collection site into an entity that could be interpreted as a distinct population. The molecular analyses were in concordance with the morphometric study as no collection location grouped into a separate population based on the two partial markers. The grouped specimens from each collection site appear to be within the normal variance of the species, indicating a single population in the southeast United States. It is recommended that additional character analyses of L. shannoni based on more molecular markers, behavioral, ecological, and physiological characteristics, be conducted before ruling out the possibility of populations or a cryptic species complex within the southeastern United States.

Collective thermal transport in pure and alloy semiconductors.

PubMed

Torres, Pol; Mohammed, Amr; Torelló, Àlvar; Bafaluy, Javier; Camacho, Juan; Cartoixà, Xavier; Shakouri, Ali; Alvarez, F Xavier

2018-03-07

Conventional models for predicting thermal conductivity of alloys usually assume a pure kinetic regime as alloy scattering dominates normal processes. However, some discrepancies between these models and experiments at very small alloy concentrations have been reported. In this work, we use the full first principles kinetic collective model (KCM) to calculate the thermal conductivity of Si 1-x Ge x and In x Ga 1-x As alloys. The calculated thermal conductivities match well with the experimental data for all alloy concentrations. The model shows that the collective contribution must be taken into account at very low impurity concentrations. For higher concentrations, the collective contribution is suppressed, but normal collisions have the effect of significantly reducing the kinetic contribution. The study thus shows the importance of the proper inclusion of normal processes even for alloys for accurate modeling of thermal transport. Furthermore, the phonon spectral distribution of the thermal conductivity is studied in the framework of KCM, providing insights to interpret the superdiffusive regime introduced in the truncated Lévy flight framework.

Mining the bitter melon (momordica charantia l.) seed transcriptome by 454 analysis of non-normalized and normalized cDNA populations for conjugated fatty acid metabolism-related genes

USDA-ARS?s Scientific Manuscript database

Seeds of Momordica charantia (bitter melon) produce high levels of eleostearic acid, an unusual conjugated fatty acid with industrial value. Deep sequencing of non-normalized and normalized cDNAs from developing bitter melon seeds was conducted to uncover key genes required for biotechnological tran...

49 CFR 192.605 - Procedural manual for operations, maintenance, and emergencies.

Code of Federal Regulations, 2010 CFR

2010-10-01

... operations and maintenance activities are conducted. (b) Maintenance and normal operations. The manual... personnel to determine the effectiveness, and adequacy of the procedures used in normal operation and... or flow rate outside normal operating limits; (iii) Loss of communications; (iv) Operation of any...

Anomalous heat conduction and anomalous diffusion in nonlinear lattices, single walled nanotubes, and billiard gas channels.

PubMed

Li, Baowen; Wang, Jiao; Wang, Lei; Zhang, Gang

2005-03-01

We study anomalous heat conduction and anomalous diffusion in low-dimensional systems ranging from nonlinear lattices, single walled carbon nanotubes, to billiard gas channels. We find that in all discussed systems, the anomalous heat conductivity can be connected with the anomalous diffusion, namely, if energy diffusion is sigma(2)(t)=2Dt(alpha) (01) implies an anomalous heat conduction with a divergent thermal conductivity (beta>0), and more interestingly, a subdiffusion (alpha<1) implies an anomalous heat conduction with a convergent thermal conductivity (beta<0), consequently, the system is a thermal insulator in the thermodynamic limit. Existing numerical data support our theoretical prediction.

Evaluation of MARC for the analysis of rotating composite blades

NASA Technical Reports Server (NTRS)

Bartos, Karen F.; Ernst, Michael A.

1993-01-01

The suitability of the MARC code for the analysis of rotating composite blades was evaluated using a four-task process. A nonlinear displacement analysis and subsequent eigenvalue analysis were performed on a rotating spring mass system to ensure that displacement-dependent centrifugal forces were accounted for in the eigenvalue analysis. Normal modes analyses were conducted on isotropic plates with various degrees of twist to evaluate MARC's ability to handle blade twist. Normal modes analyses were conducted on flat composite plates to validate the newly developed coupled COBSTRAN-MARC methodology. Finally, normal modes analyses were conducted on four composite propfan blades that were designed, analyzed, and fabricated at NASA Lewis Research Center. Results were compared with experimental data. The research documented herein presents MARC as a viable tool for the analysis of rotating composite blades.

Evaluation of MARC for the analysis of rotating composite blades

NASA Astrophysics Data System (ADS)

Bartos, Karen F.; Ernst, Michael A.

1993-03-01

The suitability of the MARC code for the analysis of rotating composite blades was evaluated using a four-task process. A nonlinear displacement analysis and subsequent eigenvalue analysis were performed on a rotating spring mass system to ensure that displacement-dependent centrifugal forces were accounted for in the eigenvalue analysis. Normal modes analyses were conducted on isotropic plates with various degrees of twist to evaluate MARC's ability to handle blade twist. Normal modes analyses were conducted on flat composite plates to validate the newly developed coupled COBSTRAN-MARC methodology. Finally, normal modes analyses were conducted on four composite propfan blades that were designed, analyzed, and fabricated at NASA Lewis Research Center. Results were compared with experimental data. The research documented herein presents MARC as a viable tool for the analysis of rotating composite blades.

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

Harner, E.J.; Gilfillan, E.S.

Two large shoreline assessment studies conducted in 1990 in Prince William Sound, Alaska, after the Exxon Valdez oil spill used different design strategies to determine the impact of oiling on shoreline biota. One of the studies, the Coastal Habitat Injury Assessment (CHIA) conducted for the Exxon Valdez Oil Spill Council, used matched pairs of sites, normal population distributions for biota, and meta-analysis. The power of the CHIA study to detect oiling impacts depends on being able to identify and select appropriate pairs of sites for comparison. The CHIA study also increased the oiling signal by focusing on moderate to heavilymore » oiled sites. The Shoreline Ecology Program (SEP), conducted for Exxon, used a stratified-random-sampling study design, normal and non-normal population distributions and covariates. The SEP study was able to detect oiling impacts by using a sufficient number of sites and widely spaced transects.« less

Ultrafast exciton dynamics in cadmium selenide nanocrystals determined by femtosecond fluorescence upconversion spectroscopy

NASA Astrophysics Data System (ADS)

Underwood, David Frederick

Femtosecond fluorescence upconversion spectroscopy is a technique that allows the unambiguous determination of the excited state dynamics of an analyte. Combining this method with the use of tunable laser excitation, the exciton dynamics in semiconducting nanocrystals (NC's) of cadmium selenide (CdSe) have been determined, devoid of the complications arising from more common spectroscopic methods such as pump-probe. The results of this investigation were used to construct a model to fully describe the three-level system comprising of the valence and conduction bands and surface states, which have been calculated by others to lie mid-gap in energy. Smaller NC's showed faster decay components due to increased interaction between the exciton and surface states. The deep trap emission, which has never before been measured by ultrafast fluorescence techniques, shows a rapid rise time (˜2 ps), which is attributed to surface selenium dangling bonds relaxing to the valence band and radiatively combining with the photo-generated hole. The band edge fluorescence decays as the deep trap emission grows in, inherently coupling the two processes. An experiment which measured the dependence of the excitation energy showed that increased energy imparted to the NC's resulted in increased rise times, yielding the timescales for exciton relaxation through the valence and conduction band states to the lowest emitting state. Surface-oxidized and normally-passivated NC's display the same decay dynamics in time but differ in relative amplitude; the latter point agrees with steady-state measurements. The rotational anisotrophy of the NC's was measured and agrees with previous pump-probe data. Upconversion on the red and blue sides of the static fluorescence spectrum showed no discernable differences, which is either and inherent limitation of the experimental apparatus, or the possibility that lower-lying triplet states are populated on a timescale below the instrument resolution.

Local bifurcations in differential equations with state-dependent delay.

PubMed

Sieber, Jan

2017-11-01

A common task when analysing dynamical systems is the determination of normal forms near local bifurcations of equilibria. As most of these normal forms have been classified and analysed, finding which particular class of normal form one encounters in a numerical bifurcation study guides follow-up computations. This paper builds on normal form algorithms for equilibria of delay differential equations with constant delay that were developed and implemented in DDE-Biftool recently. We show how one can extend these methods to delay-differential equations with state-dependent delay (sd-DDEs). Since higher degrees of regularity of local center manifolds are still open for sd-DDEs, we give an independent (still only partial) argument which phenomena from the truncated normal must persist in the full sd-DDE. In particular, we show that all invariant manifolds with a sufficient degree of normal hyperbolicity predicted by the normal form exist also in the full sd-DDE.

Theory of electrical conductivity and dielectric permittivity of highly aligned graphene-based nanocomposites.

PubMed

Xia, Xiaodong; Hao, Jia; Wang, Yang; Zhong, Zheng; Weng, George J

2017-05-24

Highly aligned graphene-based nanocomposites are of great interest due to their excellent electrical properties along the aligned direction. Graphene fillers in these composites are not necessarily perfectly aligned, but their orientations are highly confined to a certain angle, [Formula: see text] with 90° giving rise to the randomly oriented state and 0° to the perfectly aligned one. Recent experiments have shown that electrical conductivity and dielectric permittivity of highly aligned graphene-polymer nanocomposites are strongly dependent on this distribution angle, but at present no theory seems to exist to address this issue. In this work we present a new effective-medium theory that is derived from the underlying physical process including the effects of graphene orientation, filler loading, aspect ratio, percolation threshold, interfacial tunneling, and Maxwell-Wagner-Sillars polarization, to determine these two properties. The theory is formulated in the context of preferred orientational average. We highlight this new theory with an application to rGO/epoxy nanocomposites, and demonstrate that the calculated in-plane and out-of-plane conductivity and permittivity are in agreement with the experimental data as the range of graphene orientations changes from the randomly oriented to the highly aligned state. We also show that the percolation thresholds of highly aligned graphene nanocomposites are in general different along the planar and the normal directions, but they converge into a single one when the statistical distribution of graphene fillers is spherically symmetric.

The Natural History of Subclinical Hyperthyroidism in Graves' Disease: The Rule of Thirds.

PubMed

Zhyzhneuskaya, Sviatlana; Addison, Caroline; Tsatlidis, Vasileios; Weaver, Jolanta U; Razvi, Salman

2016-06-01

There is little information regarding the natural history of subclinical hyperthyroidism (SH) due to Graves' disease (GD). A prospective analysis was conducted of patients with SH due to GD between 2007 and 2013 with at least 12 months of follow-up. SH was diagnosed if serum thyrotropin (TSH) was below the laboratory reference range (0.4-4.0 mIU/L) and when thyroid hormones were normal. GD was confirmed by either a raised TSH receptor antibody (TRAb) level or uniform uptake on Technetium scan. Forty-four patients (89% female, 16% current smokers, and 5% with active Graves' orbitopathy) were diagnosed with SH due to GD. Over the follow-up period (median 32 months), approximately one third (34%) of the cohort progressed to overt hyperthyroidism, one third (34%) normalized their thyroid function, slightly less than one third (30%) remained in the SH state, while one person became hypothyroid. Multivariate regression analysis showed that older age and positive antithyroid peroxidase (TPO) antibody status had a positive association with risk of progression to overt hyperthyroidism, with hazard ratios of 1.06 ([confidence interval (CI) 1.02-1.10], p < 0.01) per year and 10.15 ([CI 1.83-56.23], p < 0.01), respectively, independent of other risk factors including, smoking, TRAb levels at diagnosis, and sex. A third each of patients with SH due to GD progress, normalize, or remain in the SH state. Older people and those with positive anti-TPO antibodies have a higher risk of progression of the disease. These novel data need to be verified and confirmed in larger cohorts and over longer periods of follow-up.

Slip behaviour of experimental faults subjected to fluid pressure stimulation: carbonates vs. shales

NASA Astrophysics Data System (ADS)

Collettini, C.; Scuderi, M. M.; Marone, C.

2017-12-01

Fluid overpressure is one of the primary mechanisms for triggering tectonic fault slip and human-induced seismicity. This mechanism has been invoked to explain the dramatic increase in seismicity associated with waste water disposal in intra-plate setting, and it is appealing because fluids lubricate the fault and reduce the effective normal stress that holds the fault in place. Although, this basic physical mechanism is well understood, several fundamental questions remain including the apparent delay between fluid injection and seismicity, the role of fault zone rheology, and the relationship between injection volume and earthquake size. Moreover, models of earthquake nucleation predict that a reduction in normal stress, as expected for fluid overpressure, should stabilize fault slip. Here, we address these questions using laboratory experiments, conducted in the double direct shear configuration in a true-triaxial machine on carbonates and shale fault gouges. In particular, we: 1) evaluate frictional strength and permeability, 2) characterize the rate- and state- friction parameters and 3) study fault slip evolution during fluid pressure stimulations. With increasing fluid pressure, when shear and effective normal stresses reach the failure condition, in calcite gouges, characterized by slightly velocity strengthening behaviour, we observe an acceleration of slip that spontaneously evolves into dynamic failure. For shale gouges, with a strong rate-strengthening behaviour, we document complex fault slip behavior characterized by periodic accelerations and decelerations with slip velocity that remains slow (i.e. v 200 µm/s), never approaching dynamic slip rates. Our data indicate that fault rheology and fault stability is controlled by the coupling between fluid pressure and rate- and state- friction parameters suggesting that their comprehensive characterization is fundamental for assessing the role of fluid pressure in natural and human induced earthquakes.

Influence of hepatic impairment on the pharmacokinetics of the dopamine agonist rotigotine.

PubMed

Cawello, Willi; Fichtner, Andreas; Boekens, Hilmar; Braun, Marina

2014-09-01

The transdermally applied dopamine receptor agonist rotigotine is extensively metabolized in the liver. An open-label, parallel-group study was conducted to evaluate the effects of moderate hepatic impairment on the pharmacokinetics, safety and tolerability of rotigotine. Eight subjects with normal hepatic function and nine with moderate hepatic impairment (Child-Pugh class B) received one rotigotine transdermal patch (providing a dose of 2 mg/24 h) daily for 3 days with a 24-h patch-on period. Blood and urine samples were collected to evaluate pharmacokinetic parameters characterizing drug bioavailability and elimination. Primary variables included plasma and urine concentrations of unconjugated rotigotine (active parent compound) and total rotigotine (unconjugated rotigotine plus sulfate and glucuronide conjugates) under steady-state (SS) conditions. For unconjugated rotigotine, point estimates for the ratios of AUC(0-24)SS and C max,SS between the two groups (normal vs. impaired hepatic function) were near 1: AUC(0-24)SS, 0.90 (90 % CI 0.59, 1.38) and C max,SS, 0.94 (90 % CI 0.66, 1.35); t max,SS and t 1/2 were lower in subjects with hepatic impairment, while renal clearance was unaffected and overall clearance was higher. For total rotigotine, C max,SS was higher in subjects with hepatic impairment compared with those with normal hepatic function (P = 0.0239, ANOVA). A tendency to reduced non-renal clearance was observed in subjects with hepatic impairment, consistent with their higher plasma concentrations of total rotigotine. Thus, moderate hepatic impairment did not influence the pharmacokinetics of unconjugated rotigotine under steady-state conditions suggesting that dose adjustment will not be required for patients with mild or moderate hepatic insufficiency. In addition, the rotigotine patch was well tolerated in subjects with moderate hepatic impairment.

Conduct problems in youth and the RDoC approach: A developmental, evolutionary-based view.

PubMed

Fonagy, Peter; Luyten, Patrick

2017-09-08

Problems related to aggression in young people are traditionally subsumed under the header of conduct problems, which include conduct disorder and oppositional defiant disorder. Such problems in children and adolescents are an important societal and mental health problem. In this paper we present an evolutionarily informed developmental psychopathology view of conduct problems inspired by the NIMH Research Domain Criteria (RDoC) initiative. We assume that while there are many pathways to conduct problems, chronic or temporary impairments in the domain of social cognition or mentalizing are a common denominator. Specifically, we conceptualize conduct problems as reflecting temporary or chronic difficulties with mentalizing, that is, the capacity to understand the self and others in terms of intentional mental states, leading to a failure to inhibit interpersonal violence through a process of perspective-taking and empathy. These difficulties, in turn, stem from impairments in making use of a normally evolutionarily protected social learning system that functions to facilitate intergenerational knowledge transmission and protect social collaborative processes from impulsive and aggressive action. Temperamental, biological, and social risk factors in different combinations may all contribute to this outcome. This adaptation then interacts with impairments in other domains of functioning, such as in negative and positive valence systems and cognitive systems. This view highlights the importance of a complex interplay among biological, psychological, and environmental factors in understanding the origins of conduct problems. We outline the implications of these views for future research and intervention. Copyright © 2017 Elsevier Ltd. All rights reserved.

Neurophysiological aspects of peripheral neuropathies.

PubMed

MacKenzie, R A; Skuse, N F; Lethlean, A K

1976-01-01

1. Eighty-eight intrafascicular neural recordings were obtained in 10 normal subjects, 5 patients with axonal degeneration and 11 patients with demyelinating neuropathy. 2. Stimulus levels required for perception and fibre activation were higher in neuropathic subjects. Fibres transmitting touch perception had significantly lower conduction velocities in both patient groups, but were very much lower in the group with demyelinating neuropahty than the group with axonal degeneration. Maximum electrical stimulation evoked dispersed fibre responses in the axonal degeneration group and more dispersed, slowly conducting fibre potentials in the demyelinating group. In patients with hypertrophic Charcot-Marie-Tooth disorder, usually only a small group of slowly conducting low amplitude potentials was recorded. 3. Delivery of a train of supramaximal stimuli caused prolongation of latency and dispersion of fibre potentials in all microneurographic recordings. The changes were significantly greater in the axonal neuropathy group than in normals, and recovery was slower. The demyelinating neuropathies showed significantly greater changes than both the normal and the axonal neuropathy groups, and post-tetanic conduction slowing became even more marked after limb temperature was raised. 4. Surface SAP recordings showed normal refractory period in chronic axonal neuropathy but significant latency prolongation occurred in demyelinating neuropathy. 5. It is concluded that both receptor and nerve fibre abnormalities contribute to sensory dysfunction in degenerative and demyelinating neuropathies.

Excited state intramolecular proton transfer reaction of 4'-N,N-diethylamino-3-hydroxyflavone and solvation dynamics in room temperature ionic liquids studied by optical Kerr gate fluorescence measurement.

PubMed

Kimura, Yoshifumi; Fukuda, Masanori; Suda, Kayo; Terazima, Masahide

2010-09-16

Fluorescence dynamics of 4'-N,N-diethylamino-3-hydroxyflavone (DEAHF) and its methoxy derivative (DEAMF) in various room temperature ionic liquids (RTILs) have been studied mainly by an optical Kerr gate method. DEAMF showed a single band fluorescence whose peak shifted with time by the solvation dynamics. The averaged solvation time determined by the fluorescence peak shift was proportional to the viscosity of the solvent except for tetradecyltrihexylphosphonium bis(trifluoromethanesulfonyl)amide. The solvation times were consistent with reported values determined with different probe molecules. DEAHF showed dual fluorescence due to the normal and tautomer forms produced by the excited state intramolecular proton transfer (ESIPT), and the relative intensities were dependent on the time and the solvent cation or anion species. By using the information of the fluorescence spectrum of DEAMF, the fluorescence spectrum of DEAHF at each delay time after the photoexcitation was decomposed into the normal and the tautomer fluorescence components, respectively. The normal component showed a very fast decay simulated by a biexponential function (2-3 and 20-30 ps) with an additional slower decay component. The tautomer component showed a rise with the time constants corresponding to the faster decay of the normal form with an additional instantaneous rise. The faster dynamics of the normal and tautomer population changes were assigned to the ESIPT process, while the slower decay of the fluorescence was attributed to the population decay from the excited state through the radiative and nonradiative processes. The average ESIPT time was much faster than the averaged solvation time of RTILs. Basically, the ESIPT kinetics in RTILs is similar to those in conventional liquid solvents like acetonitrile (Chou et al. J. Phys. Chem. A 2005, 109, 3777). The faster ESIPT is interpreted in terms of the activation barrierless process from the Franck-Condon state before the solvation of the normal state in the electronic excited state. With the advance of the solvation in the excited state, the normal form becomes relatively more stable than the tautomer form, which makes the ESIPT become an activation process.

The effect of inertia, viscous damping, temperature and normal stress on chaotic behaviour of the rate and state friction model

NASA Astrophysics Data System (ADS)

Sinha, Nitish; Singh, Arun K.; Singh, Trilok N.

2018-04-01

A fundamental understanding of frictional sliding at rock surfaces is of practical importance for nucleation and propagation of earthquakes and rock slope stability. We investigate numerically the effect of different physical parameters such as inertia, viscous damping, temperature and normal stress on the chaotic behaviour of the two state variables rate and state friction (2sRSF) model. In general, a slight variation in any of inertia, viscous damping, temperature and effective normal stress reduces the chaotic behaviour of the sliding system. However, the present study has shown the appearance of chaos for the specific values of normal stress before it disappears again as the normal stress varies further. It is also observed that magnitude of system stiffness at which chaotic motion occurs, is less than the corresponding value of critical stiffness determined by using the linear stability analysis. These results explain the practical observation why chaotic nucleation of an earthquake is a rare phenomenon as reported in literature.

Body mass index and other anthropometric variables in children with sickle cell anaemia.

PubMed

Odetunde, Odutola Israel; Chinawa, Josephat Maduabuchi; Achigbu, Kingsley Ihedioha; Achigbu, Eberechukwu O

2016-01-01

The objectives of this study were to determine the anthropometric variables of children with sickle cell anaemia and comparing it with those with normal haemoglobin genotype. A cross sectional study of anthropometric measurements was conducted over a period of six months. Children with sickle cell anaemia in steady state aged between 6-20 years were recruited. Nutritional assessment was done using anthropometrical variables. Data were analyzed using the Statistical Package for Social Sciences program (SPSS), version 20. The sickle cell patients comprised of 20 males and 20 females. There were an equal number of controls with an equal male to female ratio of 1:1. Forty eight percent (19) of the children with sickle cell anemia were underweight (< 5th %ile) and this is statistically significant. χ(2)=18.02 and p=0.000. When compared with subjects with normal haemoglobin genotype only five of them (13%) were underweight. χ(2)=10.286 and p=0.001. The controls weighed significantly more than the HbSS patients and also had significantly larger body surface compared to the HbSS population (P<0.05). BMI and other anthropometric variables among children with sickle cell anemia were low when compared with children with normal Haemoglobin genotype.

Relationship between irritable bowel syndrome, worry and stress in adolescent girls.

PubMed

Song, Sang-Wook; Park, Seo-Jin; Kim, Se-Hong; Kang, Sung-Goo

2012-11-01

The aim of this study is to investigate prevalence of irritable bowel syndrome (IBS) among adolescents and difference in worry and stress between normal and IBS groups. Questionnaire survey was conducted at a girl's middle and high school. Students from seventh to eleventh grade participated in the examination on Rome II criteria, lifestyle and dietary habits. Worry and stress were measured with the Korean version Penn State Worry Questionnaire-Children and the Korean version Brief Encounter Psychosocial Instrument. Worry score was significantly higher in the IBS group (22.07 ± 9.38, P < 0.001) than in the normal group (18.65 ± 8.99) and was higher in high school students than in middle school students (P = 0.02). Stress score also was higher in the IBS group than in the normal group (P < 0.001) and was higher in the high school girls than in the middle school ones (P = 0.04). Of all the lifestyle factors influencing IBS preference for fatty foods, preference for salty foods, drinking alcohol and sleeping for less than six hours a day were found to be significant. Worry and stress seem to be associated with IBS symptoms. The findings of this study draw a clue that less worry and stress will help decrease IBS symptoms.

Physiological and psychological effects of forest therapy on middle-aged males with high-normal blood pressure.

PubMed

Ochiai, Hiroko; Ikei, Harumi; Song, Chorong; Kobayashi, Maiko; Takamatsu, Ako; Miura, Takashi; Kagawa, Takahide; Li, Qing; Kumeda, Shigeyoshi; Imai, Michiko; Miyazaki, Yoshifumi

2015-02-25

Time spent walking and relaxing in a forest environment ("forest bathing" or "forest therapy") has well demonstrated anti-stress effects in healthy adults, but benefits for ill or at-risk populations have not been reported. The present study assessed the physiological and psychological effects of forest therapy (relaxation and stress management activity in the forest) on middle-aged males with high-normal blood pressure. Blood pressure and several physiological and psychological indices of stress were measured the day before and approximately 2 h following forest therapy. Both pre- and post-treatment measures were conducted at the same time of day to avoid circadian influences. Systolic and diastolic blood pressure (BP), urinary adrenaline, and serum cortisol were all significantly lower than baseline following forest therapy (p<0.05). Subjects reported feeling significantly more "relaxed" and "natural" according to the Semantic Differential (SD) method. Profile of Mood State (POMS) negative mood subscale scores for "tension-anxiety," "confusion," and "anger-hostility," as well as the Total Mood Disturbance (TMD) score were significantly lower following forest therapy. These results highlight that forest is a promising treatment strategy to reduce blood pressure into the optimal range and possibly prevent progression to clinical hypertension in middle-aged males with high-normal blood pressure.

Interplay between hopping and band transport in high-mobility disordered semiconductors at large carrier concentrations: The case of the amorphous oxide InGaZnO

NASA Astrophysics Data System (ADS)

Fishchuk, I. I.; Kadashchuk, A.; Bhoolokam, A.; de Jamblinne de Meux, A.; Pourtois, G.; Gavrilyuk, M. M.; Köhler, A.; Bässler, H.; Heremans, P.; Genoe, J.

2016-05-01

We suggest an analytic theory based on the effective medium approximation (EMA) which is able to describe charge-carrier transport in a disordered semiconductor with a significant degree of degeneration realized at high carrier concentrations, especially relevant in some thin-film transistors (TFTs), when the Fermi level is very close to the conduction-band edge. The EMA model is based on special averaging of the Fermi-Dirac carrier distributions using a suitably normalized cumulative density-of-state distribution that includes both delocalized states and the localized states. The principal advantage of the present model is its ability to describe universally effective drift and Hall mobility in heterogeneous materials as a function of disorder, temperature, and carrier concentration within the same theoretical formalism. It also bridges a gap between hopping and bandlike transport in an energetically heterogeneous system. The key assumption of the model is that the charge carriers move through delocalized states and that, in addition to the tail of the localized states, the disorder can give rise to spatial energy variation of the transport-band edge being described by a Gaussian distribution. It can explain a puzzling observation of activated and carrier-concentration-dependent Hall mobility in a disordered system featuring an ideal Hall effect. The present model has been successfully applied to describe experimental results on the charge transport measured in an amorphous oxide semiconductor, In-Ga-Zn-O (a-IGZO). In particular, the model reproduces well both the conventional Meyer-Neldel (MN) compensation behavior for the charge-carrier mobility and inverse-MN effect for the conductivity observed in the same a-IGZO TFT. The model was further supported by ab initio calculations revealing that the amorphization of IGZO gives rise to variation of the conduction-band edge rather than to the creation of localized states. The obtained changes agree with the one we used to describe the charge transport. We found that the band-edge variation dominates the charge transport in high-quality a-IGZO TFTs in the above-threshold voltage region, whereas the localized states need not to be invoked to account for the experimental results in this material.

Synthesis, characterization and solid state electrical properties of 1-D coordination polymer of the type [CuxNi1-x(dadb)·yH2O]n

NASA Astrophysics Data System (ADS)

Prasad, R. L.; Kushwaha, A.; Shrivastava, O. N.

2012-12-01

New heterobimetallic complexes [CuxNi1-x(dadb)·yH2O]n {where dadb=2,5-Diamino-3,6-dichloro-1,4-benzoquinone (1); x=1 (2), 0.5 (4), 0.25 (5), 0.125 (6), 0.0625 (7) and 0 (3); y=2; n=degree of polymerization} were synthesized and characterized. Heterobimetallic complexes show normal magnetic moments, whereas, monometallic complexes exhibit magnetic moments less than the value due to spin only. Thermo-gravimetric analysis shows that degradation of the ligand dadb moiety is being controlled by the electronic environment of the Cu(II) ions in preference over Ni(II) in heterobimetallic complexes. Existence of the mixed valency/non-integral oxidation states of copper and nickel metal ions in the complex 4 has been attributed from magnetic moment and ESR spectral results. Solid state dc electrical conductivity of all the complexes was investigated. Monometallic complexes were found to be semiconductors, whereas heterobimetallic coordination polymer 4 was found to exhibit metallic behaviour. Existence of mixed valency/ non-integral oxidation state of metal ions seems to be responsible for the metallic behaviour.

Surface Andreev Bound States and Odd-Frequency Pairing in Topological Superconductor Junctions

NASA Astrophysics Data System (ADS)

Tanaka, Yukio; Tamura, Shun

2018-04-01

In this review, we summarize the achievement of the physics of surface Andreev bound states (SABS) up to now. The route of this activity has started from the physics of SABS of unconventional superconductors where the pair potential has a sign change on the Fermi surface. It has been established that SABS can be regarded as a topological edge state with topological invariant defined in the bulk Hamiltonian. On the other hand, SABS accompanies odd-frequency pairing like spin-triplet s-wave or spin-singlet p-wave. In a spin-triplet superconductor junction, induced odd-frequency pairing can penetrate into a diffusive normal metal (DN) attached to the superconductor. It causes so called anomalous proximity effect where the local density of states of quasiparticle in DN has a zero energy peak. When bulk pairing symmetry is spin-triplet px-wave, the anomalous proximity effect becomes prominent and the zero bias voltage conductance is always quantized independent of the resistance in DN and interface. Finally, we show that the present anomalous proximity effect is realized in an artificial topological superconducting system, where a nanowire with spin-orbit coupling and Zeeman field is put on the conventional spin-singlet s-wave superconductor.

Dynamics of the Rydberg state population of slow highly charged ions impinging a solid surface at arbitrary collision geometry

NASA Astrophysics Data System (ADS)

Nedeljković, N. N.; Majkić, M. D.; Božanić, D. K.; Dojčilović, R. J.

2016-06-01

We consider the population dynamics of the intermediate Rydberg states of highly charged ions (core charge Z\\gg 1, principal quantum number {n}{{A}}\\gg 1) interacting with solid surfaces at arbitrary collision geometry. The recently developed resonant two-state vector model for the grazing incidence (2012 J. Phys. B: At. Mol. Opt. Phys. 45 215202) is extended to the quasi-resonant case and arbitrary angle of incidence. According to the model, the population probabilities depend both on the projectile parallel and perpendicular velocity components, in a complementary way. A cascade neutralization process for {{{Xe}}}Z+ ions, for Z=15{--}45, interacting with a conductive-surface is considered by taking into account the population dynamics. For an arbitrary collision geometry and given range of ionic velocities, a micro-staircase model for the simultaneous calculation of the kinetic energy gain and the charge state of the ion in front of the surface is proposed. The relevance of the obtained results for the explanation of the formation of nanostructures on solid surfaces by slow highly charged ions for normal incidence geometry is briefly discussed.

Top-selling childbirth advice books: a discourse analysis.

PubMed

Kennedy, Holly Powell; Nardini, Katrina; McLeod-Waldo, Rebecca; Ennis, Linda

2009-12-01

Recent evidence suggests that one-third of women receive information about pregnancy and childbirth through books. Messages about what characteristics are normal (or expected) in childbirth are disseminated in a variety of ways, including popular childbirth education books, but little study of them has been conducted. The purpose of this investigation is to address that gap by examining the discussions about childbirth in the 10 top-selling books in the United States. Discourse analysis (relating to the public, personal, and political discussions about a specific phenomenon) was used to study 10 best-selling United States childbirth advice books marketed to childbearing women during the first week of November 2007. Book styles ranged from clinical descriptions of pregnancy and birth primarily offering reassurance, self-help information, and danger signs to more folksy and humorous commentaries. Presentation of scientific evidence to support recommendations was uneven and at times inaccurate. Five focal areas of discourse included body image, labor and birth, pain, power and control, and life preparation for motherhood. Top-selling books shine an interesting light on the current state of United States maternity practices. Women and health professionals should assess them carefully and engage with each other about their recommendations and implications for childbirth.

Heat transfer and fluid mechanics measurements in transitional boundary layer flows

NASA Technical Reports Server (NTRS)

Wang, T.; Simon, T. W.; Buddhavarapu, J.

1985-01-01

Experimental results are presented to document hydrodynamic and thermal development of flat-plate boundary layers undergoing natural transition. Local heat transfer coefficients, skin friction coefficients and profiles of velocity, temperature and Reynolds normal and shear stresses are presented. A case with no transition and transitional cases with 0.68% and 2.0% free-stream disturbance intensities were investigated. The locations of transition are consistent with earlier data. A late-laminar state with significant levels of turbulence is documented. In late-transitional and early-turbulent flows, turbulent Prandtl number and conduction layer thickness values exceed, and the Reynolds analogy factor is less than, values previously measured in fully turbulent flows.

Cystic fibrosis transmembrane conductance regulator is correlated closely with sperm progressive motility and normal morphology in healthy and fertile men with normal sperm parameters.

PubMed

Jiang, L-Y; Shan, J-J; Tong, X-M; Zhu, H-Y; Yang, L-Y; Zheng, Q; Luo, Y; Shi, Q-X; Zhang, S-Y

2014-10-01

Cystic fibrosis transmembrane conductance regulator (CFTR) has been demonstrated to be expressed in mature spermatozoa and correlated with sperm quality. Sperm CFTR expression in fertile men is higher than that in infertile men suffering from teratospermia, asthenoteratospermia, asthenospermia and oligospermia, but it is unknown whether CFTR is correlated with sperm parameters when sperm parameters are normal. In this study, 282 healthy and fertile men with normal semen parameters were classified into three age groups, group (I): age group of 20-29 years (98 cases, 27.1 ± 6.2), group (II): age group of 30-39 years (142 cases, 33.7 ± 2.6) and group (III): age group of more than or equal to 40 years (42 cases, 44.1 ± 4.6). Sperm concentration, total count and progressive motility were analysed by computer-assisted sperm analysis. Sperm morphology was analysed by modified Papanicolaou staining. Sperm CFTR expression was conducted by indirect immunofluorescence staining. There was a significant positive correlation (P < 0.001) between CFTR expression and sperm progressive motility (r = 0.221) and normal morphology (r = 0.202), but there were no correlations between sperm CFTR expression and semen volume, sperm concentration, sperm total count as well as male age (P > 0.05). Our findings show that CFTR expression is associated with sperm progressive motility and normal morphology in healthy and fertile men with normal sperm parameters, but not associated with the number of spermatozoa and male age. © 2013 Blackwell Verlag GmbH.

Sibutramine promotes amygdala activity under fasting conditions in obese women.

PubMed

Oltmanns, Kerstin M; Heldmann, Marcus; Daul, Susanne; Klose, Silke; Rotte, Michael; Schäfer, Michael; Heinze, Hans-Jochen; Münte, Thomas F; Lehnert, Hendrik

2012-06-01

Sibutramine, a centrally-acting selective monoamine reuptake inhibitor, has been used as an appetite suppressant drug in obesity. To gain insight into the central nervous actions of sibutramine, brain responses to pictures of food items after sibutramine vs placebo application were assessed by functional magnetic resonance imaging (fMRI) in obese women. In a randomized double-blind crossover design, 10 healthy obese women (BMI 31.8-39.9 kg/m(2)) received 15 mg/d of sibutramine vs placebo for 14 d. Obese participants, and a group of 10 age-matched normal weight controls, viewed pictures of food items and control objects in hungry and satiated states while lying in the MR scanner. The paradigm followed a block design. In obese participants, fMRI measurements were conducted prior and after two weeks of daily sibutramine or placebo administration, whereas control participants were scanned only at one point in time. Upon food item presentation, obese participants showed increased brain activity in areas related to emotional and reward processing, perceptual processing, and cognitive control as compared to normal weight controls. Sibutramine exerted a divergent satiety-dependent effect on amygdala activity in obese participants, increasing activity in the hungry state while decreasing it under conditions of satiation. Our results demonstrate a modulatory influence of sibutramine on amygdala activity in obese women which may underlie the appetite suppressant effects of the drug.

Effect of electron-phonon coupling on the superconducting transition temperature in dodecaboride superconductors: A comparison of LuB12 with ZrB12

NASA Astrophysics Data System (ADS)

Teyssier, J.; Lortz, R.; Petrovic, A.; van der Marel, D.; Filippov, V.; Shitsevalova, N.

2008-10-01

We report a detailed study of specific heat, electrical resistivity, and optical spectroscopy in the superconducting boride LuB12 (Tc=0.4K) , and compare it to the higher Tc compound ZrB12 (Tc=6K) . Both compounds have the same structure based on enclosed metallic Lu or Zr ions in oversized boron cages. The infrared reflectivity and ellipsometry in the visible range allow us to extract the optical conductivity from 6 meV to 4 eV in the normal state from 20 to 280 K. By extracting the superconducting properties, phonon density of states, and electron-phonon coupling function from these measurements, we discuss the important factors governing Tc and explain the difference between the two compounds. The phonon density of states seems to be insignificantly modified by substitution of Zr with Lu. However, the soft vibrations of the metal ions in boron cages, responsible for the relatively high Tc in ZrB12 , have almost no contribution to the electron-phonon coupling in LuB12 .

Cardiac macrophage biology in the steady-state heart, the aging heart, and following myocardial infarction

PubMed Central

Ma, Yonggang; Mouton, Alan J.; Lindsey, Merry L.

2018-01-01

Macrophages play critical roles in homeostatic maintenance of the myocardium under normal conditions and in tissue repair after injury. In the steady-state heart, resident cardiac macrophages remove senescent and dying cells and facilitate electrical conduction. In the aging heart, the shift in macrophage phenotype to a proinflammatory subtype leads to inflammaging. Following myocardial infarction (MI), macrophages recruited to the infarct produce both proinflammatory and anti-inflammatory mediators (cytokines, chemokines, matrix metalloproteinases, and growth factors), phagocytize dead cells, and promote angiogenesis and scar formation. These diverse properties are attributed to distinct macrophage subtypes and polarization status. Infarct macrophages exhibit a proinflammatory M1 phenotype early and become polarized toward an anti-inflammatory M2 phenotype later post- MI. Although this classification system is oversimplified and needs to be refined to accommodate the multiple different macrophage subtypes that have been recently identified, general concepts on macrophage roles are independent of subtype classification. This review summarizes current knowledge about cardiac macrophage origins, roles, and phenotypes in the steady state, with aging, and after MI, as well as highlights outstanding areas of investigation. PMID:29106912

Characterization of the superconducting state in hafnium hydride under high pressure

NASA Astrophysics Data System (ADS)

Duda, A. M.; Szewczyk, K. A.; Jarosik, M. W.; Szcześniak, K. M.; Sowińska, M. A.; Szcześniak, D.

2018-05-01

The hydrogen-rich compounds at high pressure may exhibit notably high superconducting transition temperatures. In the paper, we have calculated the basic thermodynamic parameters of the superconducting state in two selected phases of HfH2 hydride under high-pressure respectively at 180 GPa for Cmma and 260 GPa for P21 / m . Calculations has been conducted in the framework of the Eliashberg formalism. In particular, we have determined the values of the critical temperature (TC) to be equal to 8 K and 13 K for the Cmma and P21 / m phases, respectively. Moreover, we have estimated other thermodynamic properties such as the order parameter (Δ (T)) , the thermodynamic critical field (HC (T)) , and the specific heat for the normal (CN) and superconducting (CS) state. Finally, we have shown that the characteristic ratios: RΔ = 2 Δ (0) /kBTC and RC = ΔC (TC) /CN (TC) , which are related to the above thermodynamic functions, slightly differ from the predictions of the Bardeen-Cooper-Schrieffer theory due to the strong-coupling and retardation effects.

A Solid-State Fibriform Supercapacitor Boosted by Host-Guest Hybridization between the Carbon Nanotube Scaffold and MXene Nanosheets.

PubMed

Yu, Chenyang; Gong, Yujiao; Chen, Ruyi; Zhang, Mingyi; Zhou, Jinyuan; An, Jianing; Lv, Fan; Guo, Shaojun; Sun, Gengzhi

2018-06-25

Fiber-shaped supercapacitors with improved specific capacitance and high rate capability are a promising candidate as power supply for smart textiles. However, the synergistic interaction between conductive filaments and active nanomaterials remains a crucial challenge, especially when hydrothermal or electrochemical deposition is used to produce a core (fiber)-shell (active materials) fibrous structure. On the other hand, although 2D pseudocapacitive materials, e.g., Ti 3 C 2 T x (MXene), have demonstrated high volumetric capacitance, high electrical conductivity, and hydrophilic characteristics, MXene-based electrodes normally suffer from poor rate capability owing to the sheet restacking especially when the loading level is high and solid-state gel is used as electrolyte. Herein, by hosting MXene nanosheets (Ti 3 C 2 T x ) in the corridor of a scrolled carbon nanotube (CNT) scaffold, a MXene/CNT fiber with helical structure is successfully fabricated. These features offer open spaces for rapid ion diffusion and guarantee fast electron transport. The solid-state supercapacitor based on such hybrid fibers with gel electrolyte coating exhibits a volumetric capacitance of 22.7 F cm -3 at 0.1 A cm -3 with capacitance retention of 84% at current density of 1.0 A cm -3 (19.1 F cm -3 ), improved volumetric energy density of 2.55 mWh cm -3 at the power density of 45.9 mW cm -3 , and excellent mechanical robustness. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Evaluation of rare earth elements in groundwater of Lagos and Ogun States, Southwest Nigeria.

PubMed

Ayedun, H; Arowolo, T A; Gbadebo, A M; Idowu, O A

2017-06-01

Rare earth elements in our environment are becoming important because of their utilization in permanent magnets, lamp phosphors, superconductors, rechargeable batteries, catalyst, ceramics and other applications. This study was conducted to evaluate the level of rare earth elements (REE) and the variability of their anomalous behavior in groundwater samples collected from Lagos and Ogun States, Southwest, Nigeria. REE concentrations were determined in 170 groundwater samples using inductively coupled plasma-mass spectrometry, while the physicochemical parameters were determined using standard methods. Lagos State groundwater is enriched with REE [sum REEs range (mean ± SD)]; [0.365-488 (69.5 ± 117)] µg L -1 than Ogun State groundwater [sum REEs range (mean ± SD)]; [1.14-232 (22.6 ± 41.1)] µg L -1 . Boreholes are more enriched with REEs than wells. Significant (P < 0.05) positive correlation (R = Pearson) was recorded in Lagos State groundwater between sum REEs and Fe (R = 0.55). However, there were no significant correlations between sum REEs, pH (R = 0.073) and HCO 3 2- (R = 0.157) in Ogun State groundwater. Chondrite-normalized plot shows that Lagos groundwater exhibits positive Ce anomaly, while Ogun State groundwater does not. The source of REE in Lagos State may be from the ocean and leaching from wastes dumpsites, while the source in Ogun State groundwater may be from the rocks.

Calculations of the first frequency moment of the structure factor in the BCS model

NASA Astrophysics Data System (ADS)

Rendell, J. M.; Carbotte, J. P.

1998-03-01

We have calculated the first frequency moment of the dynamical structure factor, S(q,ω), known as the f-sum, using the BCS model of susceptibility, \\chi(q,ω), with phenomenological models of the normal state dispersion, tilde\\varepsilon_k, and the superconducting energy gap, Δ_k(T). We have found an explicit expression for the f-sum in both the normal state and the superconducting state. Numerically, we show that the f-sum is insensitive to temperature changes in the range 0 to the order of magnitude of T_c, to the state (normal or superconducting) and to the size and type of energy gap, Δ_k(T), in the superconducting state. The f-sum does depend intimately on the normal state dispersion model, tilde\\varepsilonk and on the filling in the first Brillouin zone. In addition, we show numerically that the f-sum is nearly constant for the Random Phase Approximation (RPA) of the susceptibility up to pseudo-potentials, U <= U_c, the critical potential. Thus, a large increase in Im \\chi(q_0,ω_0) at frequency ω0 and a potential U > 0 (e.g. examining the 41 meV peak at q0 = (π,π)), is compensated by commensurate reduction in Im \\chi(q_0,ω) at other frequencies.

STEADY STATE FLAMMABLE GAS RELEASE RATE CALCULATION AND LOWER FLAMMABILITY LEVEL EVALUATION FOR HANFORD TANK WASTE

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

HU TA

2009-10-26

Assess the steady-state flammability level at normal and off-normal ventilation conditions. The hydrogen generation rate was calculated for 177 tanks using the rate equation model. Flammability calculations based on hydrogen, ammonia, and methane were performed for 177 tanks for various scenarios.

The Induction of Chaos in Electronic Circuits Final Report-October 1, 2001

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

R.M.Wheat, Jr.

2003-04-01

This project, now known by the name ''Chaos in Electronic Circuits,'' was originally tasked as a two-year project to examine various ''fault'' or ''non-normal'' operational states of common electronic circuits with some focus on determining the feasibility of exploiting these states. Efforts over the two-year duration of this project have been dominated by the study of the chaotic behavior of electronic circuits. These efforts have included setting up laboratory space and hardware for conducting laboratory tests and experiments, acquiring and developing computer simulation and analysis capabilities, conducting literature surveys, developing test circuitry and computer models to exercise and test ourmore » capabilities, and experimenting with and studying the use of RF injection as a means of inducing chaotic behavior in electronics. An extensive array of nonlinear time series analysis tools have been developed and integrated into a package named ''After Acquisition'' (AA), including capabilities such as Delayed Coordinate Embedding Mapping (DCEM), Time Resolved (3-D) Fourier Transform, and several other phase space re-creation methods. Many computer models have been developed for Spice and for the ATP (Alternative Transients Program), modeling the several working circuits that have been developed for use in the laboratory. And finally, methods of induction of chaos in electronic circuits have been explored.« less

High-velocity frictional experiments on dolerite and quartzite under controlled pore pressure

NASA Astrophysics Data System (ADS)

Togo, T.; Shimamoto, T.; Ma, S.

2013-12-01

High-velocity friction experiments on rocks with or without gouge have been conducted mostly under dry conditions and demonstrated dramatic weakening of faults at high velocities (e.g., Di Toro et al., 2011, Nature). Recent experiments under wet conditions (e.g., Ujiie and Tsutsumi, 2010, GRL; Faulkner et al., 2011, GRL) revealed very different behaviors from those of dry faults, but those experiments were done under drained conditions. Experiments with controlled pore pressure Pp are definitely needed to determine mechanical properties of faults under fluid-rich environments such as those in subduction zones. Thus we have developed a pressure vessel that can be attached to our rotary-shear low to high-velocity friction apparatus (Marui Co Ltd., MIS-233-1-76). With a current specimen holder, friction experiments can be done on hollow-cylindrical specimens of 15 and 40 mm in inner and outer diameters, respectively, at controlled Pp to 35 MPa, at effective normal stresses of 3~9 MPa, and at slip rates of 60 mm/year to 2 m/s. An effective normal stress can be applied with a 100 kN hydraulic actuator. We report an outline of the experimental system and preliminary high-velocity experiments on Shanxi dolerite and a quartzite from China that are composed of pyroxene and plagioclase and of almost pure quartz, respectively. High-velocity friction experiments were performed on hollow-cylindrical specimens of Shanxi dolerite at effective normal stresses of 0.13~1.07 MPa and at slip rates of 1, 10, 100 and 1000 mm/sec. All experiments were conducted first with the nitrogen gas filling the pressure vessel (dry tests) and then with a controlled pore-water pressure (wet tests). In the dry tests an axial force was kept at 1 kN and the nitrogen gas pressure was increased in steps to 5 MPa to change an effective normal stress. In the wet tests the specimens were soaked in distilled water in the vessel and Pp was applied by nitrogen gas in a similar manner as in the dry tests. Nitrogen gas acted as buffer to prevent an abrupt changes in the pore-water pressure during experiments. The steady-state friction coefficient (μss) of dry dolerite increased from 0.3~0.35 at 10 mm/s to 0.55~0.8 at 100 mm/s and then decreased down to 0.2~0.6 at 1000 mm/s. The results are quite similar to those of dry granite tested under similar conditions (Reches and Lockner, 2010, Nature). However, the μss of dolerite under a pore-water pressure decreased monotonically from 0.4~0.8 at 1 mm/s to 0.3~0.5 at 1000 mm/s, and the strengthening from 10 to 100 mm/s disappeared with a pore-water pressure. Two experiments were conducted on solid-cylindrical specimens of quartzite at effective normal stresses of 1.39 MPa (a dry test with CO2 gas pressure of 6.22 MPa) and of 0.99 MPa (a wet test with pore-water pressure of 6.1 MPa, also applied with pressurized CO2 gas). In dry and wet tests, the friction coefficient decreases nearly exponentially from about 0.35 at the peak friction to around 0.05 (dry) and 0.03 (wet) at the steady state. A notable difference was that wet quartzite exhibit much more rapid slip weakening with the slip weakening distance Dc of several meters than the dry specimen with Dc of about 15 m. We plan to conduct more experiments with controlled pore-water pressure and to do textural and material analysis of specimens to gain insight on the weakening mechanisms.

Impact of the charge density wave state in the electrodynamic response of ZrTe3 -xSex : Optical evidence for a pseudogap phase

NASA Astrophysics Data System (ADS)

Chinotti, M.; Ethiraj, J.; Mirri, C.; Zhu, Xiangde; Li, Lijun; Petrovic, C.; Degiorgi, L.

2018-01-01

The emergence of superconductivity upon progressively suppressing the long-range, charge-density-wave (CDW) order characterizes the phase diagram of several materials of interest in the on-going solid-state physics research. Se-doped ZrTe3 compounds provide the most recent, suitable arena in order to investigate the interplay of otherwise competing orders in layeredlike two-dimensional systems. We present an optical study of the CDW state in ZrTe3 -xSex at selected Se dopings, based on the measurement of the reflectivity from the far-infrared up to the ultraviolet, as a function of temperature. We particularly focus our attention to the redistribution of the spectral weight, which images the impact of the CDW state within the optical conductivity across the phase diagram of the title compounds. The electrodynamic response is consistent with a scenario based on a long-range CDW condensate at low Se doping. Upon increasing the Se content, this then gives way to local, short-range order CDW segments. Our spectral weight analysis reveals the presence of a pseudogap phase, as fingerprint of the CDW precursor effects and thus shaping the charge dynamics of the title compounds in their normal state, preceding the onset of superconductivity.

Optically induced lattice deformations, electronic structure changes, and enhanced superconductivity in YBa 2Cu 3O 6.48

DOE PAGES

Mankowsky, R.; Fechner, M.; Forst, M.; ...

2017-02-28

Resonant optical excitation of apical oxygen vibrational modes in the normal state of underdoped YBa 2Cu 3O 6+x induces a transient state with optical properties similar to those of the equilibrium superconducting state. Amongst these, a divergent imaginary conductivity and a plasma edge are transiently observed in the photo-stimulated state. Femtosecond hard x-ray diffraction experiments have been used in the past to identify the transient crystal structure in this non-equilibrium state. Here, we start from these crystallographic features and theoretically predict the corresponding electronic rearrangements that accompany these structural deformations. Using density functional theory, we predict enhanced hole-doping of themore » CuO 2 planes. The empty chain Cu dy2-z2 orbital is calculated to strongly reduce in energy, which would increase c-axis transport and potentially enhance the interlayer Josephson coupling as observed in the THz-frequency response. From these results, we calculate changes in the soft x-ray absorption spectra at the Cu L-edge. As a result, femtosecond x-ray pulses from a free electron laser are used to probe changes in absorption at two photon energies along this spectrum and provide data consistent with these predictions.« less

Mental state attribution in schizophrenia: what distinguishes patients with "poor" from patients with "fair" mentalising skills?

PubMed

Brüne, M; Schaub, D

2012-07-01

Although many patients with schizophrenia are impaired in mental states attribution abilities, a significant number perform within normal or near-normal ranges in mental state attribution tasks. No studies have analysed cognitive or behavioural differences between patients with - to some extent - preserved mental state attribution skills and those with poor mentalising abilities. To examine characteristics of "poor" and "fair" mentalisers, 58 patients with schizophrenia performed a mental state attribution task, a test of general intelligence, and two executive functioning tests. "Poor" and "fair" mentalising skills were defined according to a median-split procedure; the median score in the patient group was also within two standard deviations of the control group. In addition, patients' social behavioural skills and psychopathological profiles were rated. Patients performing within normal or near normal ranges on the mental state attribution task had fewer social behavioural abnormalities than patients with poor mentalising abilities (even when controlled for intelligence), but did not differ in executive functioning. Fair mental state performers showed less disorganisation and excitement symptoms than poor performers. The degree of disorganisation mediated the influence of mental state attribution on social behavioural skills. Schizophrenia patients with (partially) preserved mentalising skills have fewer behavioural problems in the social domain than patients with poor mentalising abilities. Conceptual disorganisation mediates the prediction of social behavioural skills through mentalising skills, suggesting that disorganised patients may require special attention regarding social-cognitive skills training. Copyright © 2010 Elsevier Masson SAS. All rights reserved.

Evaluating Uncertainties in Sap Flux Scaled Estimates of Forest Transpiration, Canopy Conductance and Photosynthesis

NASA Astrophysics Data System (ADS)

Ward, E. J.; Bell, D. M.; Clark, J. S.; Kim, H.; Oren, R.

2009-12-01

Thermal dissipation probes (TDPs) are a common method for estimating forest transpiration and canopy conductance from sap flux rates in trees, but their implementation is plagued by uncertainties arising from missing data and variability in the diameter and canopy position of trees, as well as sapwood conductivity within individual trees. Uncertainties in estimates of canopy conductance also translate into uncertainties in carbon assimilation in models such as the Canopy Conductance Constrained Carbon Assimilation (4CA) model that combine physiological and environmental data to estimate photosynthetic rates. We developed a method to propagate these uncertainties in the scaling and imputation of TDP data to estimates of canopy transpiration and conductance using a state-space Jarvis-type conductance model in a hierarchical Bayesian framework. This presentation will focus on the impact of these uncertainties on estimates of water and carbon fluxes using 4CA and data from the Duke Free Air Carbon Enrichment (FACE) project, which incorporates both elevated carbon dioxide and soil nitrogen treatments. We will also address the response of canopy conductance to vapor pressure deficit, incident radiation and soil moisture, as well as the effect of treatment-related stand structure differences in scaling TDP measurements. Preliminary results indicate that in 2006, a year of normal precipitation (1127 mm), canopy transpiration increased in elevated carbon dioxide ~8% on a ground area basis. In 2007, a year with a pronounced drought (800 mm precipitation), this increase was only present in the combined carbon dioxide and fertilization treatment. The seasonal dynamics of water and carbon fluxes will be discussed in detail.

Corresponding states correlation for temperature dependent surface tension of normal saturated liquids

NASA Astrophysics Data System (ADS)

Yi, Huili; Tian, Jianxiang

2014-07-01

A new simple correlation based on the principle of corresponding state is proposed to estimate the temperature-dependent surface tension of normal saturated liquids. The correlation is a linear one and strongly stands for 41 saturated normal liquids. The new correlation requires only the triple point temperature, triple point surface tension and critical point temperature as input and is able to represent the experimental surface tension data for these 41 saturated normal liquids with a mean absolute average percent deviation of 1.26% in the temperature regions considered. For most substances, the temperature covers the range from the triple temperature to the one beyond the boiling temperature.

Andreev bound states probed in three-terminal quantum dots

NASA Astrophysics Data System (ADS)

Gramich, J.; Baumgartner, A.; Schönenberger, C.

2017-11-01

Andreev bound states (ABSs) are well-defined many-body quantum states that emerge from the hybridization of individual quantum dot (QD) states with a superconductor and exhibit very rich and fundamental phenomena. We demonstrate several electron transport phenomena mediated by ABSs that form on three-terminal carbon nanotube (CNT) QDs, with one superconducting (S) contact in the center and two adjacent normal-metal (N) contacts. Three-terminal spectroscopy allows us to identify the coupling to the N contacts as the origin of the Andreev resonance (AR) linewidths and to determine the critical coupling strengths to S, for which a ground state (or quantum phase) transition in such S-QD systems can occur. In addition, we ascribe replicas of the lowest-energy ABS resonance to transitions between the ABS and odd-parity excited QD states, a process we call excited state ABS resonances. In the conductance between the two N contacts we find a characteristic pattern of positive and negative differential subgap conductance, which we explain by considering two nonlocal processes, the creation of Cooper pairs in S by electrons from both N terminals, and a transport mechanism we call resonant ABS tunneling, possible only in multiterminal QD devices. In the latter process, electrons are transferred via the ABS without effectively creating Cooper pairs in S. The three-terminal geometry also allows spectroscopy experiments with different boundary conditions, for example by leaving S floating. Surprisingly, we find that, depending on the boundary conditions and the device parameters, the experiments either show single-particle Coulomb blockade resonances, ABS characteristics, or both in the same measurements, seemingly contradicting the notion of ABSs replacing the single-particle states as eigenstates of the QD. We qualitatively explain these results as originating from the finite time scale required for the coherent oscillations between the superposition states after a single-electron tunneling event. These experiments demonstrate that three-terminal experiments on a single complex quantum object can also be useful to investigate charge dynamics otherwise not accessible due to the very high frequencies.

Physical models for the normal YORP and diurnal Yarkovsky effects

NASA Astrophysics Data System (ADS)

Golubov, O.; Kravets, Y.; Krugly, Yu. N.; Scheeres, D. J.

2016-06-01

We propose an analytic model for the normal Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) and diurnal Yarkovsky effects experienced by a convex asteroid. Both the YORP torque and the Yarkovsky force are expressed as integrals of a universal function over the surface of an asteroid. Although in general this function can only be calculated numerically from the solution of the heat conductivity equation, approximate solutions can be obtained in quadratures for important limiting cases. We consider three such simplified models: Rubincam's approximation (zero heat conductivity), low thermal inertia limit (including the next order correction and thus valid for small heat conductivity), and high thermal inertia limit (valid for large heat conductivity). All three simplified models are compared with the exact solution.

The origin of nulls mode changes and timing noise in pulsars

NASA Astrophysics Data System (ADS)

Jones, P. B.

A solvable polar cap model obtained previously has normal states which may be associated with radio emission and null states. The solutions cannot be time-independent; the neutron star surface temperature T and mean surface nuclear charge Z are both functions of time. The normal and null states, and the transitions between them, form closed cycles in the T-Z plane. Normal-null transitions can occur inside a fraction of the area on the neutron star surface intersected by open magnetic flux lines. The fraction increases with pulsar period and becomes unity when the pulsar nears extinction. Frequency noise, mode changes, and pulse nulls have a common explanation in the transitions.

The origin of nulls, mode changes and timing noise in pulsars

NASA Astrophysics Data System (ADS)

Jones, P. B.

1982-09-01

A solvable polar cap model obtained previously has normal states which may be associated with radio emission, and null states. The solutions cannot be time-independent; the neutron star surface temperature T and mean surface nuclear charge Z are both functions of time. The normal and null states and the transitions between them, form closed cycles in the T-Z plane. Normal-null transitions can occur inside a fraction of the area of the neutron star surface intersected by open magnetic flux lines. The fraction increases with pulsar period and becomes unity when the pulsar nears extinction. Frequency noise, mode changes and pulse nulls have a common explanation in the transitions.

Quantum spin Hall effect and topological phase transition in InN x Bi y Sb1-x-y /InSb quantum wells

NASA Astrophysics Data System (ADS)

Song, Zhigang; Bose, Sumanta; Fan, Weijun; Zhang, Dao Hua; Zhang, Yan Yang; Shen Li, Shu

2017-07-01

Quantum spin Hall (QSH) effect, a fundamentally new quantum state of matter and topological phase transitions are characteristics of a kind of electronic material, popularly referred to as topological insulators (TIs). TIs are similar to ordinary insulator in terms of their bulk bandgap, but have gapless conducting edge-states that are topologically protected. These edge-states are facilitated by the time-reversal symmetry and they are robust against nonmagnetic impurity scattering. Recently, the quest for new materials exhibiting non-trivial topological state of matter has been of great research interest, as TIs find applications in new electronics and spintronics and quantum-computing devices. Here, we propose and demonstrate as a proof-of-concept that QSH effect and topological phase transitions can be realized in {{InN}}x{{Bi}}y{{Sb}}1-x-y/InSb semiconductor quantum wells (QWs). The simultaneous incorporation of nitrogen and bismuth in InSb is instrumental in lowering the bandgap, while inducing opposite kinds of strain to attain a near-lattice-matching conducive for lattice growth. Phase diagram for bandgap shows that as we increase the QW thickness, at a critical thickness, the electronic bandstructure switches from a normal to an inverted type. We confirm that such transition are topological phase transitions between a traditional insulator and a TI exhibiting QSH effect—by demonstrating the topologically protected edge-states using the bandstructure, edge-localized distribution of the wavefunctions and edge-state spin-momentum locking phenomenon, presence of non-zero conductance in spite of the Fermi energy lying in the bandgap window, crossover points of Landau levels in the zero-mode indicating topological band inversion in the absence of any magnetic field and presence of large Rashba spin-splitting, which is essential for spin-manipulation in TIs.

Effect of signal to noise ratio on the speech perception ability of older adults

PubMed Central

Shojaei, Elahe; Ashayeri, Hassan; Jafari, Zahra; Zarrin Dast, Mohammad Reza; Kamali, Koorosh

2016-01-01

Background: Speech perception ability depends on auditory and extra-auditory elements. The signal- to-noise ratio (SNR) is an extra-auditory element that has an effect on the ability to normally follow speech and maintain a conversation. Speech in noise perception difficulty is a common complaint of the elderly. In this study, the importance of SNR magnitude as an extra-auditory effect on speech perception in noise was examined in the elderly. Methods: The speech perception in noise test (SPIN) was conducted on 25 elderly participants who had bilateral low–mid frequency normal hearing thresholds at three SNRs in the presence of ipsilateral white noise. These participants were selected by available sampling method. Cognitive screening was done using the Persian Mini Mental State Examination (MMSE) test. Results: Independent T- test, ANNOVA and Pearson Correlation Index were used for statistical analysis. There was a significant difference in word discrimination scores at silence and at three SNRs in both ears (p≤0.047). Moreover, there was a significant difference in word discrimination scores for paired SNRs (0 and +5, 0 and +10, and +5 and +10 (p≤0.04)). No significant correlation was found between age and word recognition scores at silence and at three SNRs in both ears (p≥0.386). Conclusion: Our results revealed that decreasing the signal level and increasing the competing noise considerably reduced the speech perception ability in normal hearing at low–mid thresholds in the elderly. These results support the critical role of SNRs for speech perception ability in the elderly. Furthermore, our results revealed that normal hearing elderly participants required compensatory strategies to maintain normal speech perception in challenging acoustic situations. PMID:27390712

Kondo physics from quasiparticle poisoning in Majorana devices

DOE PAGES

Plugge, S.; Tsvelik, A. M.; Zazunov, A.; ...

2016-03-24

Here, we present a theoretical analysis of quasiparticle poisoning in Coulomb-blockaded Majorana fermion systems tunnel-coupled to normal-conducting leads. Taking into account finite-energy quasiparticles, we derive the effective low-energy theory and present a renormalization group analysis. We find qualitatively new effects when a quasiparticle state with very low energy is localized near a tunnel contact. For M = 2 attached leads, such “dangerous” quasiparticle poisoning processes cause a spin S = 1/2 single-channel Kondo effect, which can be detected through a characteristic zero-bias anomaly conductance peak in all Coulomb blockade valleys. For more than two attached leads, the topological Kondo effectmore » of the unpoisoned system becomes unstable. A strong-coupling bosonization analysis indicates that at low energy the poisoned lead is effectively decoupled and hence, for M > 3, the topological Kondo fixed point re-emerges, though now it involves only M–1 leads. As a consequence, for M = 3, the low-energy fixed point becomes trivial corresponding to decoupled leads.« less

Wiedemann-Franz ratio in high-pressure and low-temperature thermal xenon plasma with 10% caesium

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

Novakovic, N.V.; Milic, B.S.; Stojilkovic, S.M.

1995-12-31

Theoretical investigations of various transport properties of low-temperature noble-gas plasmas with additives has aroused a continuous interest over a considerable spall of time, due to numerous applications. In this paper the results of a theoretical evaluation of electrical conductivity, thermal conductivity and their ratio (the Wiedemann-Franz ratio) in xenon plasma with 10% of argon and 10% of caesium are presented, for the temperature range from 2000 K to 20000 K, and for pressures equal to or 5, 10, and 15 time higher than the normal atmospheric pressure. The plasma was regarded as weakly non-ideal and in the state of localmore » thermodynamical equilibrium with the assumption that the equilibrium is attained with the pressure kept constant. The plasma composition was determined on the ground of a set of Saha equations; the ionization energy lowerings were expressed with the aid of a modified plasma Debye radius r*{sub D} (rather than the standard r{sub D}), as proposed previously.« less

Ballistic superconductivity in semiconductor nanowires

PubMed Central

Zhang, Hao; Gül, Önder; Conesa-Boj, Sonia; Nowak, Michał P.; Wimmer, Michael; Zuo, Kun; Mourik, Vincent; de Vries, Folkert K.; van Veen, Jasper; de Moor, Michiel W. A.; Bommer, Jouri D. S.; van Woerkom, David J.; Car, Diana; Plissard, Sébastien R; Bakkers, Erik P.A.M.; Quintero-Pérez, Marina; Cassidy, Maja C.; Koelling, Sebastian; Goswami, Srijit; Watanabe, Kenji; Taniguchi, Takashi; Kouwenhoven, Leo P.

2017-01-01

Semiconductor nanowires have opened new research avenues in quantum transport owing to their confined geometry and electrostatic tunability. They have offered an exceptional testbed for superconductivity, leading to the realization of hybrid systems combining the macroscopic quantum properties of superconductors with the possibility to control charges down to a single electron. These advances brought semiconductor nanowires to the forefront of efforts to realize topological superconductivity and Majorana modes. A prime challenge to benefit from the topological properties of Majoranas is to reduce the disorder in hybrid nanowire devices. Here we show ballistic superconductivity in InSb semiconductor nanowires. Our structural and chemical analyses demonstrate a high-quality interface between the nanowire and a NbTiN superconductor that enables ballistic transport. This is manifested by a quantized conductance for normal carriers, a strongly enhanced conductance for Andreev-reflecting carriers, and an induced hard gap with a significantly reduced density of states. These results pave the way for disorder-free Majorana devices. PMID:28681843

Sharks and people: insight into the global practices of tourism operators and their attitudes to shark behaviour.

PubMed

Richards, Kirsty; O'Leary, Bethan C; Roberts, Callum M; Ormond, Rupert; Gore, Mauvis; Hawkins, Julie P

2015-02-15

Shark tourism is a popular but controversial activity. We obtained insights into this industry via a global e-mailed questionnaire completed by 45 diving/snorkelling operators who advertised shark experiences (shark operators) and 49 who did not (non-shark operators). 42% of shark operators used an attractant to lure sharks and 93% stated they had a formal code of conduct which 86% enforced "very strictly". While sharks were reported to normally ignore people, 9 operators had experienced troublesome behaviour from them. Whilst our research corroborates previous studies indicating minimal risk to humans from most shark encounters, a precautionary approach to provisioning is required to avoid potential ecological and societal effects of shark tourism. Codes of conduct should always stipulate acceptable diver behaviour and appropriate diver numbers and shark operators should have a moral responsibility to educate their customers about the need for shark conservation. Copyright © 2014 Elsevier Ltd. All rights reserved.

CNN-based ranking for biomedical entity normalization.

PubMed

Li, Haodi; Chen, Qingcai; Tang, Buzhou; Wang, Xiaolong; Xu, Hua; Wang, Baohua; Huang, Dong

2017-10-03

Most state-of-the-art biomedical entity normalization systems, such as rule-based systems, merely rely on morphological information of entity mentions, but rarely consider their semantic information. In this paper, we introduce a novel convolutional neural network (CNN) architecture that regards biomedical entity normalization as a ranking problem and benefits from semantic information of biomedical entities. The CNN-based ranking method first generates candidates using handcrafted rules, and then ranks the candidates according to their semantic information modeled by CNN as well as their morphological information. Experiments on two benchmark datasets for biomedical entity normalization show that our proposed CNN-based ranking method outperforms traditional rule-based method with state-of-the-art performance. We propose a CNN architecture that regards biomedical entity normalization as a ranking problem. Comparison results show that semantic information is beneficial to biomedical entity normalization and can be well combined with morphological information in our CNN architecture for further improvement.

Median and ulnar neuropathies in university guitarists.

PubMed

Kennedy, Rachel H; Hutcherson, Kimberly J; Kain, Jennifer B; Phillips, Alicia L; Halle, John S; Greathouse, David G

2006-02-01

Descriptive study. To determine the presence of median and ulnar neuropathies in both upper extremities of university guitarists. Peripheral nerve entrapment syndromes of the upper extremities are well documented in musicians. Guitarists and plucked-string musicians are at risk for entrapment neuropathies in the upper extremities and are prone to mild neurologic deficits. Twenty-four volunteer male and female guitarists (age range, 18-26 years) were recruited from the Belmont University School of Music and the Vanderbilt University Blair School of Music. Individuals were excluded if they were pregnant or had a history of recent upper extremity or neck injury. Subjects completed a history form, were interviewed, and underwent a physical examination. Nerve conduction status of the median and ulnar nerves of both upper extremities was obtained by performing motor, sensory, and F-wave (central) nerve conduction studies. Descriptive statistics of the nerve conduction study variables were computed using Microsoft Excel. Six subjects had positive findings on provocative testing of the median and ulnar nerves. Otherwise, these guitarists had normal upper extremity neural and musculoskeletal function based on the history and physical examinations. When comparing the subjects' nerve conduction study values with a chart of normal nerve conduction studies values, 2 subjects had prolonged distal motor latencies (DMLs) of the left median nerve of 4.3 and 4.7 milliseconds (normal, < 4.2 milliseconds). Prolonged DMLs are compatible with median neuropathy at or distal to the wrist. Otherwise, all electrophysiological variables were within normal limits for motor, sensory, and F-wave (central) values. However, comparison studies of median and ulnar motor latencies in the same hand demonstrated prolonged differences of greater than 1.0 milliseconds that affected the median nerve in 2 additional subjects, and identified contralateral limb involvement in a subject with a prolonged distal latency. The other 20 subjects demonstrated normal comparison studies of the median and ulnar nerves in both upper extremities. In this descriptive study of a population of 24 university guitarists, 4 musicians (17%) were found to have electrophysiologic evidence of median neuropathy at or distal to the wrist or carpal tunnel syndrome. Ulnar nerve electrophysiological function was within normal limits for all subjects examined.

Versatile solid-state relay

NASA Technical Reports Server (NTRS)

Fox, D. A.

1977-01-01

Solid-state relay (SSR), containing multinode control logic, is operated as normally open, normally closed, or latched. Moreover several can be paralleled to form two-pole or double-throw relays. Versatile unit ends need to design custom control circuit for every relay application. Technique can be extended to incorporate selectable time delay, on operation or release, or pulsed output.

Higher resting-state activity in reward-related brain circuits in obese versus normal-weight females independent of food intake.

PubMed

Hogenkamp, P S; Zhou, W; Dahlberg, L S; Stark, J; Larsen, A L; Olivo, G; Wiemerslage, L; Larsson, E-M; Sundbom, M; Benedict, C; Schiöth, H B

2016-11-01

In response to food cues, obese vs normal-weight individuals show greater activation in brain regions involved in the regulation of food intake under both fasted and sated conditions. Putative effects of obesity on task-independent low-frequency blood-oxygenation-level-dependent signals-that is, resting-state brain activity-in the context of food intake are, however, less well studied. To compare eyes closed, whole-brain low-frequency BOLD signals between severely obese and normal-weight females, as assessed by functional magnetic resonance imaging (fMRI). Fractional amplitude of low-frequency fluctuations were measured in the morning following an overnight fast in 17 obese (age: 39±11 years, body mass index (BMI): 42.3±4.8 kg m - 2 ) and 12 normal-weight females (age: 36±12 years, BMI: 22.7±1.8 kg m - 2 ), both before and 30 min after consumption of a standardized meal (~260 kcal). Compared with normal-weight controls, obese females had increased low-frequency activity in clusters located in the putamen, claustrum and insula (P<0.05). This group difference was not altered by food intake. Self-reported hunger dropped and plasma glucose concentrations increased after food intake (P<0.05); however, these changes did not differ between the BMI groups. Reward-related brain regions are more active under resting-state conditions in obese than in normal-weight females. This difference was independent of food intake under the experimental settings applied in the current study. Future studies involving males and females, as well as utilizing repeated post-prandial resting-state fMRI scans and various types of meals are needed to further investigate how food intake alters resting-state brain activity in obese humans.

Characterization of stem cells and cancer cells on the basis of gene expression profile stability, plasticity, and robustness: dynamical systems theory of gene expressions under cell-cell interaction explains mutational robustness of differentiated cells and suggests how cancer cells emerge.

PubMed

Kaneko, Kunihiko

2011-06-01

Here I present and discuss a model that, among other things, appears able to describe the dynamics of cancer cell origin from the perspective of stable and unstable gene expression profiles. In identifying such aberrant gene expression profiles as lying outside the normal stable states attracted through development and normal cell differentiation, the hypothesis explains why cancer cells accumulate mutations, to which they are not robust, and why these mutations create a new stable state far from the normal gene expression profile space. Such cells are in strong contrast with normal cell types that appeared as an attractor state in the gene expression dynamical system under cell-cell interaction and achieved robustness to noise through evolution, which in turn also conferred robustness to mutation. In complex gene regulation networks, other aberrant cellular states lacking such high robustness are expected to remain, which would correspond to cancer cells. Copyright © 2011 WILEY Periodicals, Inc.

30 CFR 48.10 - Compensation for training.

Code of Federal Regulations, 2010 CFR

2010-07-01

... training. (a) Training shall be conducted during normal working hours; miners attending such training shall receive the rate of pay as provided in § 48.2(d) (Definition of normal working hours) of this subpart A...

Superconductivity of Ca2 InN with a layered structure embedding an anionic indium chain array

NASA Astrophysics Data System (ADS)

Jeong, Sehoon; Matsuishi, Satoru; Lee, Kimoon; Toda, Yoshitake; Wng Kim, Sung; Hosono, Hideo

2014-05-01

We report the emergence of superconductivity in Ca2InN consisting of a two-dimensional (2D) array of zigzag indium chains embedded between Ca2N layers. A sudden drop of resistivity and a specific heat (Cp) jump attributed to the superconducting transition were observed at 0.6 K. The Sommerfeld coefficient γ = 4.24 mJ mol-1K-2 and Debye temperature ΘD = 322 K were determined from the Cp of the normal conducting state and the superconducting volume fraction was estimated to be ˜80% from the Cp jump, assuming a BCS-type weak coupling. Density functional theory calculations demonstrated that the electronic bands near the Fermi level (EF) are mainly derived from In 5p orbitals with π and σ bonding states and the Fermi surface is composed of cylindrical parts, corresponding to the quasi-2D electronic state of the In-chain array. By integrating the projected density of states of the In-p component up to EF, a valence electron population of ˜1.6 electrons/In was calculated, indicating that partially anionic state of In. The In 3d binding energies observed in Ca2InN by x-ray photoemission spectroscopy were negatively shifted from that in In metal. The superconductivity of Ca2InN is associated with the p-p bonding states of the anionic In layer.

A STUDY OF COGNITIVE DEVELOPMENT AND PERFORMANCE IN CHILDREN WITH NORMAL AND DEFECTIVE HEARING.

ERIC Educational Resources Information Center

TEMPLIN, MILDRED C.

A COMPARATIVE, LONGITUDINAL STUDY WAS CONDUCTED TO EXAMINE SPECIFIC PERFORMANCE CHARACTERISTICS OF DEAF AND NORMAL CHILDREN ON SELECTED COGNITIVE TASKS. THE SAMPLE, DISTRIBUTED INTO 3 AGE CATEGORIES, CONSISTED OF 72 NORMAL AND 60 DEAF CHILDREN. MEASURES WERE SELECTED TO ASSESS THE PERFORMANCE OF SUBJECTS (1) IN DIFFERENT AREAS OF COGNITION, (2) BY…

Do Perceptions of Gifted Intelligence and Normal Intelligence Participants Differ about Social Science and Social Scientists?

ERIC Educational Resources Information Center

Selvi, Sezgin; Demir, Selçuk Besir

2017-01-01

This qualitative study was conducted to compare the perceptions of students with gifted intelligence and students with those of normal intelligence about social science and social scientists. The data obtained from 23 gifted intelligent and 23 normal participants within the same age group was analysed using content analysis and results were…

A psychophysiological investigation of moral judgment after ventromedial prefrontal damage.

PubMed

Moretto, Giovanna; Làdavas, Elisabetta; Mattioli, Flavia; di Pellegrino, Giuseppe

2010-08-01

Converging evidence suggests that emotion processing mediated by ventromedial prefrontal cortex (vmPFC) is necessary to prevent personal moral violations. In moral dilemmas, for example, patients with lesions in vmPFC are more willing than normal controls to approve harmful actions that maximize good consequences (e.g., utilitarian moral judgments). Yet, none of the existing studies has measured subjects' emotional responses while they considered moral dilemmas. Therefore, a direct link between emotion processing and moral judgment is still lacking. Here, vmPFC patients and control participants considered moral dilemmas while skin conductance response (SCR) was measured as a somatic index of affective state. Replicating previous evidence, vmPFC patients approved more personal moral violations than did controls. Critically, we found that, unlike control participants, vmPFC patients failed to generate SCRs before endorsing personal moral violations. In addition, such anticipatory SCRs correlated negatively with the frequency of utilitarian judgments in normal participants. These findings provide direct support to the hypothesis that the vmPFC promotes moral behavior by mediating the anticipation of the emotional consequences of personal moral violations.

Growth of normally-immiscible materials (NIMs), binary alloys, and metallic fibers by hyperbaric laser chemical vapor deposition

NASA Astrophysics Data System (ADS)

Maxwell, J. L.; Black, M. R.; Chavez, C. A.; Maskaly, K. R.; Espinoza, M.; Boman, M.; Landstrom, L.

2008-06-01

This work demonstrates that two or more elements of negligible solubility (and no known phase diagram) can be co-deposited in fiber form by hyperbaric-pressure laser chemical vapor deposition (HP-LCVD). For the first time, Hg-W alloys were grown as fibers from mixtures of tungsten hexafluoride, mercury vapor, and hydrogen. This new class of materials is termed normally-immiscible materials (NIMs), and includes not only immiscible materials, but also those elemental combinations that have liquid states at exclusive temperatures. This work also demonstrates that a wide variety of other binary and ternary alloys, intermetallics, and mixtures can be grown as fibers, e.g. silicon-tungsten, aluminum-silicon, boron-carbon-silicon, and titanium-carbon-nitride. In addition, pure metallic fibers of aluminum, titanium, and tungsten were deposited, demonstrating that materials of high thermal conductivity can indeed be grown in three-dimensions, provided sufficient vapor pressures are employed. A wide variety of fiber properties and microstructures resulted depending on process conditions; for example, single crystals, fine-grained alloys, and glassy metals could be deposited.

On a Heat Exchange Problem under Sharply Changing External Conditions

NASA Astrophysics Data System (ADS)

Khishchenko, K. V.; Charakhch'yan, A. A.; Shurshalov, L. V.

2018-02-01

The heat exchange problem between carbon particles and an external environment (water) is stated and investigated based on the equations of heat conducting compressible fluid. The environment parameters are supposed to undergo large and fast variations. In the time of about 100 μs, the temperature of the environment first increases from the normal one to 2400 K, is preserved at this level for about 60 μs, and then decreases to 300 K during approximately 50 μs. At the same periods of time, the pressure of the external environment increases from the normal one to 67 GPa, is preserved at this level, and then decreases to zero. Under such external conditions, the heating of graphite particles of various sizes, their phase transition to the diamond phase, and the subsequent unloading and cooling almost to the initial values of the pressure and temperature without the reverse transition from the diamond to the graphite phase are investigated. Conclusions about the maximal size of diamond particles that can be obtained in experiments on the shock compression of the mixture of graphite with water are drawn.

The mechanism by which nonlinearity sustains turbulence in plane Couette flow

NASA Astrophysics Data System (ADS)

Nikolaidis, M.-A.; Farrell, B. F.; Ioannou, P. J.

2018-04-01

Turbulence in wall-bounded shear flow results from a synergistic interaction between linear non-normality and nonlinearity in which non-normal growth of a subset of perturbations configured to transfer energy from the externally forced component of the turbulent state to the perturbation component maintains the perturbation energy, while the subset of energy-transferring perturbations is replenished by nonlinearity. Although it is accepted that both linear non-normality mediated energy transfer from the forced component of the mean flow and nonlinear interactions among perturbations are required to maintain the turbulent state, the detailed physical mechanism by which these processes interact in maintaining turbulence has not been determined. In this work a statistical state dynamics based analysis is performed on turbulent Couette flow at R = 600 and a comparison to DNS is used to demonstrate that the perturbation component in Couette flow turbulence is replenished by a non-normality mediated parametric growth process in which the fluctuating streamwise mean flow has been adjusted to marginal Lyapunov stability. It is further shown that the alternative mechanism in which the subspace of non-normally growing perturbations is maintained directly by perturbation-perturbation nonlinearity does not contribute to maintaining the turbulent state. This work identifies parametric interaction between the fluctuating streamwise mean flow and the streamwise varying perturbations to be the mechanism of the nonlinear interaction maintaining the perturbation component of the turbulent state, and identifies the associated Lyapunov vectors with positive energetics as the structures of the perturbation subspace supporting the turbulence.

Experimental analysis of surface finish in normal conducting cavities

NASA Astrophysics Data System (ADS)

Zarrebini-Esfahani, A.; Aslaninejad, M.; Ristic, M.; Long, K.

2017-10-01

A normal conducting 805 MHz test cavity with an in built button shaped sample is used to conduct a series of surface treatment experiments. The button enhances the local fields and influences the likelihood of an RF breakdown event. Because of their smaller sizes, compared to the whole cavity surface, they allow practical investigations of the effects of cavity surface preparation in relation to RF breakdown. Manufacturing techniques and steps for preparing the buttons to improve the surface quality are described in detail. It was observed that even after the final stage of the surface treatment, defects on the surface of the cavities still could be found.

Effects of Hearing Loss on Heart-Rate Variability and Skin Conductance Measured During Sentence Recognition in Noise

PubMed Central

Mackersie, Carol L.; MacPhee, Imola X.; Heldt, Emily W.

2014-01-01

SHORT SUMMARY (précis) Sentence recognition by participants with and without hearing loss was measured in quiet and in babble noise while monitoring two autonomic nervous system measures: heart-rate variability and skin conductance. Heart-rate variability decreased under difficult listening conditions for participants with hearing loss, but not for participants with normal hearing. Skin conductance noise reactivity was greater for those with hearing loss, than for those with normal hearing, but did not vary with the signal-to-noise ratio. Subjective ratings of workload/stress obtained after each listening condition were similar for the two participant groups. PMID:25170782

Distribution Characteristics of Air-Bone Gaps – Evidence of Bias in Manual Audiometry

PubMed Central

Margolis, Robert H.; Wilson, Richard H.; Popelka, Gerald R.; Eikelboom, Robert H.; Swanepoel, De Wet; Saly, George L.

2015-01-01

Objective Five databases were mined to examine distributions of air-bone gaps obtained by automated and manual audiometry. Differences in distribution characteristics were examined for evidence of influences unrelated to the audibility of test signals. Design The databases provided air- and bone-conduction thresholds that permitted examination of air-bone gap distributions that were free of ceiling and floor effects. Cases with conductive hearing loss were eliminated based on air-bone gaps, tympanometry, and otoscopy, when available. The analysis is based on 2,378,921 threshold determinations from 721,831 subjects from five databases. Results Automated audiometry produced air-bone gaps that were normally distributed suggesting that air- and bone-conduction thresholds are normally distributed. Manual audiometry produced air-bone gaps that were not normally distributed and show evidence of biasing effects of assumptions of expected results. In one database, the form of the distributions showed evidence of inclusion of conductive hearing losses. Conclusions Thresholds obtained by manual audiometry show tester bias effects from assumptions of the patient’s hearing loss characteristics. Tester bias artificially reduces the variance of bone-conduction thresholds and the resulting air-bone gaps. Because the automated method is free of bias from assumptions of expected results, these distributions are hypothesized to reflect the true variability of air- and bone-conduction thresholds and the resulting air-bone gaps. PMID:26627469

Superconductivity in two-dimensional NbSe2 field effect transistors

NASA Astrophysics Data System (ADS)

El-Bana, Mohammed S.; Wolverson, Daniel; Russo, Saverio; Balakrishnan, Geetha; Mck Paul, Don; Bending, Simon J.

2013-12-01

We describe investigations of superconductivity in few molecular layer NbSe2 field effect transistors. While devices fabricated from NbSe2 flakes less than eight molecular layers thick did not conduct, thicker flakes were superconducting with an onset Tc that was only slightly depressed from the bulk value for 2H-NbSe2 (7.2 K). The resistance typically showed a small, sharp high temperature transition followed by one or more broader transitions which usually ended in a wide tail to zero resistance at low temperatures. We speculate that these multiple resistive transitions are related to disorder in the layer stacking. The behavior of several flakes has been characterized as a function of temperature, applied field and back-gate voltage. We find that the conductance in the normal state and transition temperature depend weakly on the gate voltage, with both conductivity and Tc decreasing as the electron concentration is increased. The application of a perpendicular magnetic field allows the evolution of different resistive transitions to be tracked and values of the zero temperature upper critical field, Hc2(0), and coherence length, ξ(0), to be independently estimated. Our results are analyzed in terms of available theories for these phenomena.

Bifurcations of the Creation of Low-Temperature Maxima of the Tunneling Conductance of a "Dirty" N-I-N Junction

NASA Astrophysics Data System (ADS)

Kirpichenkov, V. Ya.; Kirpichenkova, N. V.; Lozin, O. I.; Pukhlova, A. A.

2017-05-01

The representation of the tunneling conductance G(T) of the "dirty" (with low concentrations of the same nonmagnetic impurities in the I layer) N-I-N junction (where N is a normal metal and I is an insulator) in the form of a sum of conductances of random quantum jumpers penetrating the disordered I layer is obtained in the low-temperature region. It is shown that the axis of the parameter δ = |ɛ0 - ɛF| giving the deviation of the energy of ɛ0 the quasi-local electron state on the impurity in the I layer from the Fermi energy of ɛF the dirty N-I-N junction contains a series of bifurcation points, at the transition through each of which (in the direction of the increase in δ) the number of maxima on the temperature dependence G(T) increases by unity; i.e., a new maximum is "born" on the curve G(T). Numerical estimates are given for the characteristic parameters of dirty N-I-N junctions indicating the possibility of the experimental observation of at least the first of these maxima.

Experimental transport studies of yttrium barium copper oxide and lambda-DNA

NASA Astrophysics Data System (ADS)

Zhang, Yuexing

This dissertation consists of two parts. In Part I, we focus on the quasi-particle transport properties in the high temperature superconductor YBa2Cu3O7-delta (YBCO), probed by the thermal Hall conductivity (kappa xy). The thermal Hall conductivity selectively reflects the transport behaviors of the charge carriers. By measuring kappaxy in the normal state YBCO, we established a new method to determine the Wiedemann-Franz (WF) ratio in cuprates. We determined the Hall-channel WF ratio kappa xy/sigmaxyT in Cu and YBCO. In the latter, we uncovered a T-linear dependence and suppression of the Hallchannel WF ratio. The suppression of the Hall-channel WF ratio in systems with predominant electron-electron scattering will be discussed. Thermal transport behaviors of the quasi-particles in the mixed state were studied by measuring kappaxx and kappa xy in a high-purity YBCO crystal. From the field-dependence of the thermal conductivity kappaxx, we separated the quasi particle contribution (kappae) from the phonon background. In the Hall channel, we observed that the (weak-field) kappa xy increased 103-fold between T c (90 K) and 30 K, implying a 100-fold enhancement of the quasi-particle lifetime. We found that kappaxy exhibited a specific scaling behavior below ˜30 K. The implication of the scaling behavior will be discussed. In Part II, we describe an experiment on determining the electrical conductivity of the bacteriophage lambda-DNA, an issue currently under intense debate. We covalently bonded the DNA to Au electrodes by incorporating thiol modified dTTP into the 'sticky' ends of the lambda-DNA. Two-probe measurements on such molecules provided a lower bound for the resistivity rho > 10 6 mum at bias potentials up to 20 V, in conflict with recent claims of moderate to high conductivity. We stress the importance of eliminating salt residues in these measurements.

Enhanced disease characterization through multi network functional normalization in fMRI.

PubMed

Çetin, Mustafa S; Khullar, Siddharth; Damaraju, Eswar; Michael, Andrew M; Baum, Stefi A; Calhoun, Vince D

2015-01-01

Conventionally, structural topology is used for spatial normalization during the pre-processing of fMRI. The co-existence of multiple intrinsic networks which can be detected in the resting brain are well-studied. Also, these networks exhibit temporal and spatial modulation during cognitive task vs. rest which shows the existence of common spatial excitation patterns between these identified networks. Previous work (Khullar et al., 2011) has shown that structural and functional data may not have direct one-to-one correspondence and functional activation patterns in a well-defined structural region can vary across subjects even for a well-defined functional task. The results of this study and the existence of the neural activity patterns in multiple networks motivates us to investigate multiple resting-state networks as a single fusion template for functional normalization for multi groups of subjects. We extend the previous approach (Khullar et al., 2011) by co-registering multi group of subjects (healthy control and schizophrenia patients) and by utilizing multiple resting-state networks (instead of just one) as a single fusion template for functional normalization. In this paper we describe the initial steps toward using multiple resting-state networks as a single fusion template for functional normalization. A simple wavelet-based image fusion approach is presented in order to evaluate the feasibility of combining multiple functional networks. Our results showed improvements in both the significance of group statistics (healthy control and schizophrenia patients) and the spatial extent of activation when a multiple resting-state network applied as a single fusion template for functional normalization after the conventional structural normalization. Also, our results provided evidence that the improvement in significance of group statistics lead to better accuracy results for classification of healthy controls and schizophrenia patients.

Changes in aerodynamics during vocal cord dysfunction.

PubMed

Frank-Ito, Dennis O; Schulz, Kristine; Vess, Gina; Witsell, David L

2015-02-01

Changes in laryngeal airflow dynamics during episodes of vocal cord dysfunction (VCD) have not been well described. Very little is known about how inspiratory airflow is impacted when the vocal cords transition from normal inhalation state to a paradoxical adducted state; and how much change in laryngeal airflow and resistance occur before symptoms of stridor and air hunger emerge. This study provides new insight on the effects of VCD on respiratory airflow using computational fluid dynamics (CFD) techniques. Computed tomography images of a subject with normal vocal cords opening at the time of scanning were digitally modified to mimic an episode of VCD. To quantify and compare changes in inspiratory flow during VCD attack and normal inhalation, steady-state, laminar simulations were performed for three different breathing rates. Pressure-flow analysis during VCD revealed that increasing inspiratory effort is not as efficient as in normal inhalation. Airflow resistance at the epiglottis was higher in the normal state (0.04Pa.s/mL versus 0.02Pa.s/mL) than in VCD; while resistance at the glottis and trachea remained roughly the same (0.04Pa.s/mL) during normal inhalation, it escalated during VCD (0.11Pa.s/mL and 0.13Pa.s/mL at the glottis and trachea, respectively). Peak airflow velocity and vorticity occurred around the glottis during VCD, and at the epiglottis during normal inhalation. This pilot study demonstrates that attempting to force more inspired air will yield greater glottal resistance during VCD. Furthermore, there were evidence of abrupt laryngeal pressure gradient, chaotic airflow and high concentration of shear stresses in the glottal region. Copyright © 2014 Elsevier Ltd. All rights reserved.

The utility of an online diagnostic decision support system (Isabel) in general practice: a process evaluation.

PubMed

Henderson, Emily J; Rubin, Greg P

2013-05-01

To evaluate the utility of Isabel, an online diagnostic decision support system developed by Isabel Healthcare primarily for secondary medical care, in the general practice setting. Focus groups were conducted with clinicians to understand why and how they used the system. A modified online post-use survey asked practitioners about its impact on their decision-making. Normalization process theory (NPT) was used as a theoretical framework to determine whether the system could be incorporated into routine clinical practice. The system was introduced by NHS County Durham and Darlington in the UK in selected general practices as a three-month pilot. General practitioners and nurse practitioners who had access to Isabel as part of the Primary Care Trust's pilot. General practitioners' views, experiences and usage of the system. Seven general practices agreed to pilot Isabel. Two practices did not subsequently use it. The remaining five practices conducted searches on 16 patients. Post-use surveys (n = 10) indicated that Isabel had little impact on diagnostic decision-making. Focus group participants stated that, although the diagnoses produced by Isabel in general did not have an impact on their decision-making, they would find the tool useful if it were better tailored to the primary care setting. Our analysis concluded that normalization was not likely to occur in its current form. Isabel was of limited utility in this short pilot study and may need further modification for use in general practice.

Detecting the tipping points in a three-state model of complex diseases by temporal differential networks.

PubMed

Chen, Pei; Li, Yongjun; Liu, Xiaoping; Liu, Rui; Chen, Luonan

2017-10-26

The progression of complex diseases, such as diabetes and cancer, is generally a nonlinear process with three stages, i.e., normal state, pre-disease state, and disease state, where the pre-disease state is a critical state or tipping point immediately preceding the disease state. Traditional biomarkers aim to identify a disease state by exploiting the information of differential expressions for the observed molecules, but may fail to detect a pre-disease state because there are generally little significant differences between the normal and pre-disease states. Thus, it is challenging to signal the pre-disease state, which actually implies the disease prediction. In this work, by exploiting the information of differential associations among the observed molecules between the normal and pre-disease states, we propose a temporal differential network based computational method to accurately signal the pre-disease state or predict the occurrence of severe disease. The theoretical foundation of this work is the quantification of the critical state using dynamical network biomarkers. Considering that there is one stationary Markov process before reaching the tipping point, a novel index, inconsistency score (I-score), is proposed to quantitatively measure the change of the stationary processes from the normal state so as to detect the onset of pre-disease state. In other words, a drastic increase of I-score implies the high inconsistency with the preceding stable state and thus signals the upcoming critical transition. This approach is applied to the simulated and real datasets of three diseases, which demonstrates the effectiveness of our method for predicting the deterioration into disease states. Both functional analysis and pathway enrichment also validate the computational results from the perspectives of both molecules and networks. At the molecular network level, this method provides a computational way of unravelling the underlying mechanism of the dynamical progression when a biological system is near the tipping point, and thus detecting the early-warning signal of the imminent critical transition, which may help to achieve timely intervention. Moreover, the rewiring of differential networks effectively extracts discriminatively interpretable features, and systematically demonstrates the dynamical change of a biological system.

Hydrodynamic lubrication of rigid nonconformal contacts in combined rolling and normal motion

NASA Technical Reports Server (NTRS)

Ghosh, M. K.; Hamrock, B. J.; Brewe, D. E.

1984-01-01

A numerical solution to the problem of hydrodynamic lubrication of rigid point contacts with an isoviscous, incompressible lubricant was obtained. The hydrodynamic load-carrying capacity under unsteady (or dynamic) conditions arising from the combined effects of squeeze motion superposed upon the entraining motion was determined for both normal approach and separation. Superposed normal motion considerably increases net load-carrying capacity during normal approach and substantially reduces net load-carrying capacity during separation. Geometry was also found to have a significant influence on the dynamic load-carrying capacity. The ratio of dynamic to steady state load-carrying capacity increases with increasing geometry parameter for normal approach and decreases during separation. The cavitation (film rupture) boundary is also influenced significantly by the normal motion, moving downstream during approach and upstream during separation. For sufficiently high normal separation velocity the rupture boundary may even move upstream of the minimum-film-thickness position. Sixty-three cases were used to derive a functional relationship for the ratio of the dynamic to steady state load-carrying capacity in terms of the dimensionless normal velocity parameter (incorporating normal velocity, entraining velocity, and film thickness) and the geometry parameter.

Hydrodynamic lubrication of rigid nonconformal contacts in combined rolling and normal motion

NASA Technical Reports Server (NTRS)

Ghosh, M. K.; Hamrock, B. J.; Brewe, D.

1985-01-01

A numerical solution to the problem of hydrodynamic lubrication of rigid point contacts with an isoviscous, incompressible lubricant was obtained. The hydrodynamic load-carrying capacity under unsteady (or dynamic) conditions arising from the combined effects of squeeze motion superposed upon the entraining motion was determined for both normal approach and separation. Superposed normal motion considerably increases net load-carrying capacity during normal approach and substantially reduces net load-carrying capacity during separation. Geometry was also found to have a significant influence on the dynamic load-carrying capacity. The ratio of dynamic to steady state load-carrying capacity increases with increasing geometry parameter for normal approach and decreases during separation. The cavitation (film rupture) boundary is also influenced significantly by the normal motion, moving downstream during approach and upstream during separation. For sufficiently high normal separation velocity the rupture boundary may even move upstream of the minimum-film-thickness position. Sixty-three cases were used to derive a functional relationship for the ratio of the dynamic to steady state load-carrying capacity in terms of the dimensionless normal velocity parameter (incorporating normal velocity, entraining velocity, and film thickness) and the geometry parameter.

Development of the method and U.S. normalization database for Life Cycle Impact Assessment and sustainability metrics.

PubMed

Bare, Jane; Gloria, Thomas; Norris, Gregory

2006-08-15

Normalization is an optional step within Life Cycle Impact Assessment (LCIA) that may be used to assist in the interpretation of life cycle inventory data as well as life cycle impact assessment results. Normalization transforms the magnitude of LCI and LCIA results into relative contribution by substance and life cycle impact category. Normalization thus can significantly influence LCA-based decisions when tradeoffs exist. The U. S. Environmental Protection Agency (EPA) has developed a normalization database based on the spatial scale of the 48 continental U.S. states, Hawaii, Alaska, the District of Columbia, and Puerto Rico with a one-year reference time frame. Data within the normalization database were compiled based on the impact methodologies and lists of stressors used in TRACI-the EPA's Tool for the Reduction and Assessment of Chemical and other environmental Impacts. The new normalization database published within this article may be used for LCIA case studies within the United States, and can be used to assist in the further development of a global normalization database. The underlying data analyzed for the development of this database are included to allow the development of normalization data consistent with other impact assessment methodologies as well.

Electron localization mechanism in the normal state of high- T c superconductors

NASA Astrophysics Data System (ADS)

Yamani, Z.; Akhavan, M.

The ceramic compounds Gd 1- xPr xCu 3O 7- y (GdPr-123) with 0.0 ≤ x≤1.0, were synthesized by standard solid state reaction technique. XRD analysis shows a predominantly single phase perovskite structure with the orthorhombic Pmmm symmetry. The samples have been examined for superconductivity by measuring electrical resistivity within the temperature range 10-300 K. These measurements show a suppression of superconductivity with increasing x. It is observed that the critical Pr concentration ( x cr) required to suppress superconductivity is about 0.45, the samples with x < 0.45 become superconducting and are metallic in their normal state, the samples with x ≥ 0.45 do not become superconducting and show a semiconducting behavior above 10 K. To interpret the normal state properties of the samples, the quantum percolation theory based on localized states is applied. A cross-over between variable-range hopping (VRH) and Coulomb gap (CG) mechanisms is observed as a result of decreasing the Pr content.

Specific heat in KFe2As2 in zero and applied magnetic field

NASA Astrophysics Data System (ADS)

Kim, J. S.; Kim, E. G.; Stewart, G. R.; Chen, X. H.; Wang, X. F.

2011-05-01

The specific heat down to 0.08 K of the iron pnictide superconductor KFe2As2 was measured on a single-crystal sample with a residual resistivity ratio of ˜650, with a Tconset determined by a specific heat of 3.7 K. The zero-field normal-state specific heat divided by temperature, C/T, was extrapolated from above Tc to T=0 by insisting on agreement between the extrapolated normal-state entropy at Tc, Snextrap(Tc), and the measured superconducting-state entropy at Tc, Ssmeas(Tc), since for a second-order phase transition the two entropies must be equal. This extrapolation would indicate that this rather clean sample of KFe2As2 exhibits non-Fermi-liquid behavior; i.e., C/T increases at low temperatures, in agreement with the reported non-Fermi-liquid behavior in the resistivity. However, specific heat as a function of magnetic field shows that the shoulder feature around 0.7 K, which is commonly seen in KFe2As2 samples, is not evidence for a second superconducting gap as has been previously proposed but instead is due to an unknown magnetic impurity phase, which can affect the entropy balance and the extrapolation of the normal-state specific heat. This peak (somewhat larger in magnitude) with similar field dependence is also found in a less pure sample of KFe2As2, with a residual resistivity ratio of only 90 and Tconset=3.1 K. These data, combined with the measured normal-state specific heat in field to suppress superconductivity, allow the conclusion that an increase in the normal-state specific heat as T→0 is in fact not seen in KFe2As2; i.e., Fermi-liquid behavior is observed.

High-field specific heats of A15 V3Si and Nb3Sn

NASA Astrophysics Data System (ADS)

Stewart, G. R.; Brandt, B. L.

1984-04-01

In order to further understand the anomalous behavior of the specific heat of Nb3Sn in an 18-T magnetic field discovered by Stewart, Cort, and Webb

Militarism's Killing Fields: From Gaza to Ferguson

ERIC Educational Resources Information Center

Giroux, Henry

2014-01-01

Militarization and a military definition of life and culture have become normalized in the United States. This article explores the ways in which a military metaphysics has become the new normal for a nation not only at war abroad but also at home, especially with regards to the ongoing assaults waged by the state against youth, immigrants, and…

Surface impedance and optimum surface resistance of a superconductor with an imperfect surface

NASA Astrophysics Data System (ADS)

Gurevich, Alex; Kubo, Takayuki

2017-11-01

We calculate a low-frequency surface impedance of a dirty, s -wave superconductor with an imperfect surface incorporating either a thin layer with a reduced pairing constant or a thin, proximity-coupled normal layer. Such structures model realistic surfaces of superconducting materials which can contain oxide layers, absorbed impurities, or nonstoichiometric composition. We solved the Usadel equations self-consistently and obtained spatial distributions of the order parameter and the quasiparticle density of states which then were used to calculate a low-frequency surface resistance Rs(T ) and the magnetic penetration depth λ (T ) as functions of temperature in the limit of local London electrodynamics. It is shown that the imperfect surface in a single-band s -wave superconductor results in a nonexponential temperature dependence of Z (T ) at T ≪Tc which can mimic the behavior of multiband or d -wave superconductors. The imperfect surface and the broadening of the gap peaks in the quasiparticle density of states N (ɛ ) in the bulk give rise to a weakly temperature-dependent residual surface resistance. We show that the surface resistance can be optimized and even reduced below its value for an ideal surface by engineering N (ɛ ) at the surface using pair-breaking mechanisms, particularly by incorporating a small density of magnetic impurities or by tuning the thickness and conductivity of the normal layer and its contact resistance. The results of this work address the limit of Rs in superconductors at T ≪Tc , and the ways of engineering the optimal density of states by surface nanostructuring and impurities to reduce losses in superconducting microresonators, thin-film strip lines, and radio-frequency cavities for particle accelerators.

Interactions between the thyroid hormones and the hormones of the growth hormone axis.

PubMed

Laron, Zvi

2003-12-01

The normal secretion and action of the thyroid hormones and the hormones of the GH/IGF-I (growth hormone/ insulin-like growth factor I) axis are interdependent. Their interactions often differ in man from animal studies in rodents and sheep. Thus neonates with congenital hypothyroidism are of normal length in humans but IUGR (intrauterine growth retardation) in sheep. Postnatally normal GH/IGF-I secretion and action depends on an euthyroid state. Present knowledge on the interactions between the two axes is reviewed in states of hypo- and hyperthyroidism, states of GH/IGF-I deprivation and hypersecretion, as well as the relationship between IGF-I and thyroid cancer. Emphasis is given to data in children and aspects of linear growth and skeletal maturation.

Diffusion-Cooled Tantalum Hot-Electron Bolometer Mixers

NASA Technical Reports Server (NTRS)

Skalare, Anders; McGrath, William; Bumble, Bruce; LeDuc, Henry

2004-01-01

A batch of experimental diffusion-cooled hot-electron bolometers (HEBs), suitable for use as mixers having input frequencies in the terahertz range and output frequencies up to about a gigahertz, exploit the superconducting/normal-conducting transition in a thin strip of tantalum. The design and operation of these HEB mixers are based on mostly the same principles as those of a prior HEB mixer that exploited the superconducting/normal- conducting transition in a thin strip of niobium and that was described elsewhere.

Doubled full shot noise in quantum coherent superconductor-semiconductor junctions.

PubMed

Lefloch, F; Hoffmann, C; Sanquer, M; Quirion, D

2003-02-14

We performed low temperature shot noise measurements in superconductor (TiN) strongly disordered normal metal (heavily doped Si) weakly transparent junctions. We show that the conductance has a maximum due to coherent multiple Andreev reflections at low energy and that the shot noise is then twice the Poisson noise (S = 4eI). When the subgap conductance reaches its minimum at finite voltage the shot noise changes to the normal value (S = 2eI) due to a large quasiparticle contribution.

Expression of the cystic fibrosis transmembrane conductance regulator gene in the respiratory tract of normal individuals and individuals with cystic fibrosis

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

Trapnell, B.C.; Chinshyan Chu; Paakko, P.K.

1991-08-01

The most common mutation of the cystic fibrosis transmembrane conductance regulator gene, CFTR, associated with the clinical disorder cystic fibrosis (CF) is called {Delta}Phe{sup 508}, a triple-base deletion resulting in loss of phenylalanine at residue 508 of the predicted 1480-amino acid CFTR protein. In the context that the lung is the major site of morbidity and mortality in CF, the authors evaluated airway epithelial cells for CFTR mRNA transcripts in normal individuals, normal-{Delta}Phe{sup 508} heterozygotes, and {Delta}Phe{sup 508} homozygotes to determine if the normal and {Delta}Phe{sup 508} CFTR alleles are expressed in the respiratory epithelium, to what extent they aremore » expressed, and whether there are relative differences in the expression of the normal and abnormal alleles at the mRNA level. Respiratory tract epithelial cells recovered by fiberoptic bronchoscopy with a cytology brush demonstrated CFTR mRNA transcripts with sequences appropriately reflecting the normal and {Delta}Phe{sup 508} CFTR alleles of the various study groups. CFTR gene expression quantified by limited polymerase chain reaction amplification showed that in normal individuals, CFTR mRNA transcripts are expressed in nasal, tracheal, and bronchial epithelial cells.« less

Bipolar mood state reflected in cortico-amygdala resting state connectivity: A cohort and longitudinal study.

PubMed

Brady, Roscoe O; Margolis, Allison; Masters, Grace A; Keshavan, Matcheri; Öngür, Dost

2017-08-01

Using resting-state functional magnetic resonance imaging (rsfMRI), we previously compared cohorts of bipolar I subjects in a manic state to those in a euthymic state to identify mood state-specific patterns of cortico-amygdala connectivity. Our results suggested that mania is reflected in the disruption of emotion regulation circuits. We sought to replicate this finding in a group of subjects with bipolar disorder imaged longitudinally across states of mania and euthymia METHODS: We divided our subjects into three groups: 26 subjects imaged in a manic state, 21 subjects imaged in a euthymic state, and 10 subjects imaged longitudinally across both mood states. We measured differences in amygdala connectivity between the mania and euthymia cohorts. We then used these regions of altered connectivity to examine connectivity in the longitudinal bipolar group using a within-subjects design. Our findings in the mania vs euthymia cohort comparison were replicated in the longitudinal analysis. Bipolar mania was differentiated from euthymia by decreased connectivity between the amygdala and pre-genual anterior cingulate cortex. Mania was also characterized by increased connectivity between amygdala and the supplemental motor area, a region normally anti-correlated to the amygdala in emotion regulation tasks. Stringent controls for movement effects limited the number of subjects in the longitudinal sample. In this first report of rsfMRI conducted longitudinally across mood states, we find that previously observed between-group differences in amygdala connectivity are also found longitudinally within subjects. These results suggest resting state cortico-amygdala connectivity is a biomarker of mood state in bipolar disorder. Copyright © 2017 Elsevier B.V. All rights reserved.

A sub-1-volt analog metal oxide memristive-based synaptic device with large conductance change for energy-efficient spike-based computing systems

NASA Astrophysics Data System (ADS)

Hsieh, Cheng-Chih; Roy, Anupam; Chang, Yao-Feng; Shahrjerdi, Davood; Banerjee, Sanjay K.

2016-11-01

Nanoscale metal oxide memristors have potential in the development of brain-inspired computing systems that are scalable and efficient. In such systems, memristors represent the native electronic analogues of the biological synapses. In this work, we show cerium oxide based bilayer memristors that are forming-free, low-voltage (˜|0.8 V|), energy-efficient (full on/off switching at ˜8 pJ with 20 ns pulses, intermediate states switching at ˜fJ), and reliable. Furthermore, pulse measurements reveal the analog nature of the memristive device; that is, it can directly be programmed to intermediate resistance states. Leveraging this finding, we demonstrate spike-timing-dependent plasticity, a spike-based Hebbian learning rule. In those experiments, the memristor exhibits a marked change in the normalized synaptic strength (>30 times), when the pre- and post-synaptic neural spikes overlap. This demonstration is an important step towards the physical construction of high density and high connectivity neural networks.

Study of cost/benefit tradeoffs for reducing the energy consumption of the commercial air transportation system. [Advanced turboprop introduction

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

Coykendall, R.E.; Curry, J.K.; Domke, A.E.

1976-06-01

Economic studies were conducted for three general fuel-conserving options: (1) improving fuel-consumption characteristics of existing aircraft via retrofit modifications; (2) introducing fuel-efficient derivations of existing production aircraft and/or introducing fuel efficient, current state-of-the-art new aircraft; and (3) introducing an advanced state-of-the-art turboprop airplane. These studies were designed to produce an optimum airline fleet mix for the years 1980, 1985 and 1990. The fleet selected accommodated a normal growth market by introducing somewhat larger aircraft while solving for maximum departure frequencies and a minimum load factor corresponding to a 15% investment hurdle rate. Fuel burnt per available-seat-mile flown would drop 22%more » from 1980 to 1990 due to the use of more fuel efficient aircraft designs, larger average aircraft size, and increased seating density. An inflight survey was taken to determine air traveler attitudes towards a new generation of advanced turboprops. (Author) (GRA)« less

Infrared photodetectors based on graphene van der Waals heterostructures

NASA Astrophysics Data System (ADS)

Ryzhii, V.; Ryzhii, M.; Svintsov, D.; Leiman, V.; Mitin, V.; Shur, M. S.; Otsuji, T.

2017-08-01

We propose and evaluate the graphene layer (GL) infrared photodetectors (GLIPs) based on the van der Waals (vdW) heterostructures with the radiation absorbing GLs. The operation of the GLIPs is associated with the electron photoexcitation from the GL valence band to the continuum states above the inter-GL barriers (either via tunneling or direct transitions to the continuum states). Using the developed device model, we calculate the photodetector characteristics as functions of the GL-vdW heterostructure parameters. We show that due to a relatively large efficiency of the electron photoexcitation and low capture efficiency of the electrons propagating over the barriers in the inter-GL layers, GLIPs should exhibit the elevated photoelectric gain and detector responsivity as well as relatively high detectivity. The possibility of high-speed operation, high conductivity, transparency of the GLIP contact layers, and the sensitivity to normally incident IR radiation provides additional potential advantages in comparison with other IR photodetectors. In particular, the proposed GLIPs can compete with unitravelling-carrier photodetectors.

Electrical measurement of the hydration state of the skin surface in vivo.

PubMed

Tagami, H

2014-09-01

Healthy skin surface is smooth and soft, because it is covered by the properly hydrated stratum corneum (SC), an extremely thin and soft barrier membrane produced by the underlying normal epidermis. By contrast, the skin surfaces covering pathological lesions exhibit dry and scaly changes and the SC shows poor barrier function. The SC barrier function has been assessed in vivo by instrumentally measuring transepidermal water loss (TEWL). However, there was a lack of any appropriate method for evaluating the hydration state of the skin surface in vivo until 1980 when we reported the feasibility of employing high-frequency conductance or capacitance to evaluate it quickly and accurately. With such measurements, we can assess easily the moisturizing efficacy of various topical agents in vivo as well as the distribution pattern of water in the SC by combining it with a serial tape-stripping procedure of the skin surface. © 2014 The Author BJD © 2014 British Association of Dermatologists.

Modeling and simulation performance of photovoltaic system integration battery and supercapacitor paralellization of MPPT prototipe for solar vehicle

NASA Astrophysics Data System (ADS)

Ajiatmo, Dwi; Robandi, Imam

2017-03-01

This paper proposes a control scheme photovoltaic, battery and super capacitor connected in parallel for use in a solar vehicle. Based on the features of battery charging, the control scheme consists of three modes, namely, mode dynamic irradian, constant load mode and constant voltage charging mode. The shift of the three modes can be realized by controlling the duty cycle of the mosffet Boost converter system. Meanwhile, the high voltage which is more suitable for the application can be obtained. Compared with normal charging method with parallel connected current limiting detention and charging method with dynamic irradian mode, constant load mode and constant voltage charging mode, the control scheme is proposed to shorten the charging time and increase the use of power generated from the PV array. From the simulation results and analysis conducted to determine the performance of the system in state transient and steady-state by using simulation software Matlab / Simulink. Response simulation results demonstrate the suitability of the proposed concept.

Many-Body Spectral Functions from Steady State Density Functional Theory.

PubMed

Jacob, David; Kurth, Stefan

2018-03-14

We propose a scheme to extract the many-body spectral function of an interacting many-electron system from an equilibrium density functional theory (DFT) calculation. To this end we devise an ideal scanning tunneling microscope (STM) setup and employ the recently proposed steady-state DFT formalism (i-DFT) which allows one to calculate the steady current through a nanoscopic region coupled to two biased electrodes. In our setup, one of the electrodes serves as a probe ("STM tip"), which is weakly coupled to the system we want to measure. In the ideal STM limit of vanishing coupling to the tip, the system is restored to quasi-equilibrium and the normalized differential conductance yields the exact equilibrium many-body spectral function. Calculating this quantity from i-DFT, we derive an exact relation expressing the interacting spectral function in terms of the Kohn-Sham one. As illustrative examples, we apply our scheme to calculate the spectral functions of two nontrivial model systems, namely the single Anderson impurity model and the Constant Interaction Model.

Nodal quasiparticle dynamics in the heavy fermion superconductor CeCoIn₅ revealed by precision microwave spectroscopy.

PubMed

Truncik, C J S; Huttema, W A; Turner, P J; Ozcan, S; Murphy, N C; Carrière, P R; Thewalt, E; Morse, K J; Koenig, A J; Sarrao, J L; Broun, D M

2013-01-01

CeCoIn₅ is a heavy fermion superconductor with strong similarities to the high-Tc cuprates, including quasi-two-dimensionality, proximity to antiferromagnetism and probable d-wave pairing arising from a non-Fermi-liquid normal state. Experiments allowing detailed comparisons of their electronic properties are of particular interest, but in most cases are difficult to realize, due to their very different transition temperatures. Here we use low-temperature microwave spectroscopy to study the charge dynamics of the CeCoIn₅ superconducting state. The similarities to cuprates, in particular to ultra-clean YBa₂Cu₃O(y), are striking: the frequency and temperature dependence of the quasiparticle conductivity are instantly recognizable, a consequence of rapid suppression of quasiparticle scattering below T(c); and penetration-depth data, when properly treated, reveal a clean, linear temperature dependence of the quasiparticle contribution to superfluid density. The measurements also expose key differences, including prominent multiband effects and a temperature-dependent renormalization of the quasiparticle mass.

Fault stability under conditions of variable normal stress

USGS Publications Warehouse

Dieterich, J.H.; Linker, M.F.

1992-01-01

The stability of fault slip under conditions of varying normal stress is modelled as a spring and slider system with rate- and state-dependent friction. Coupling of normal stress to shear stress is achieved by inclining the spring at an angle, ??, to the sliding surface. Linear analysis yields two conditions for unstable slip. The first, of a type previously identified for constant normal stress systems, results in instability if stiffness is below a critical value. Critical stiffness depends on normal stress, constitutive parameters, characteristic sliding distance and the spring angle. Instability of the first type is possible only for velocity-weakening friction. The second condition yields instability if spring angle ?? <-cot-1??ss, where ??ss is steady-state sliding friction. The second condition can arise under conditions of velocity strengthening or weakening. Stability fields for finite perturbations are investigated by numerical simulation. -Authors

Normalization of reverse redistribution of thallium-201 with procainamide pretreatment in Wolff-Parkinson-White syndrome

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

Nii, T.; Nakashima, Y.; Nomoto, J.

1991-03-01

Stress thallium-201 myocardial perfusion imaging was performed in a patient with Wolff-Parkinson-White syndrome. Reverse redistribution phenomenon was observed in the absence of coronary artery disease. This seems to be the first report of normalization of this phenomenon in association with reversion of accessory pathway to normal atrioventricular conduction after pretreatment with procainamide.

Towards Principled Experimental Study of Autonomous Mobile Robots

NASA Technical Reports Server (NTRS)

Gat, Erann

1995-01-01

We review the current state of research in autonomous mobile robots and conclude that there is an inadequate basis for predicting the reliability and behavior of robots operating in unengineered environments. We present a new approach to the study of autonomous mobile robot performance based on formal statistical analysis of independently reproducible experiments conducted on real robots. Simulators serve as models rather than experimental surrogates. We demonstrate three new results: 1) Two commonly used performance metrics (time and distance) are not as well correlated as is often tacitly assumed. 2) The probability distributions of these performance metrics are exponential rather than normal, and 3) a modular, object-oriented simulation accurately predicts the behavior of the real robot in a statistically significant manner.

[Investigation of psychological state and its influencing factors in children with epilepsy].

PubMed

Zhao, Jin-Hua; Zhou, Hui; Xu, Ming; Lu, Sheng-Li; Hong, Fei

2015-06-01

To evaluate the psychological state of children with epilepsy and analyze its influencing factors. The Mental Health Scale for Child and Adolescent was used to survey 113 children with epilepsy and 114 normal children to evaluate and compare their psychological state. Questionnaires were used to investigate the general status of all subjects and the disease condition and treatment of children with epilepsy. The possible influencing factors for the psychological state of children with epilepsy were analyzed. The mental health status of children with epilepsy was poorer than that of normal children in cognition, thinking, emotion, will-behavior, and personality traits (P<0.05). Multivariate logistic regression analysis showed that family education, family relations, seizure frequency, seizure duration, EEG epileptiform discharges in the last six months, and number of types of antiepileptic drugs were correlated with the psychological state of children with epilepsy. There is a wider range of psychological health problems in children with epilepsy than in normal children. Poor family living environment, poor seizure control, and use of many antiepileptic drugs are the risk factors affecting the psychological state of children with epilepsy. Improving family living environment, controlling seizures, and monotherapy help to improve the psychological state of children with epilepsy.

Thermodynamics of an Attractive 2D Fermi Gas

NASA Astrophysics Data System (ADS)

Fenech, K.; Dyke, P.; Peppler, T.; Lingham, M. G.; Hoinka, S.; Hu, H.; Vale, C. J.

2016-01-01

Thermodynamic properties of matter are conveniently expressed as functional relations between variables known as equations of state. Here we experimentally determine the compressibility, density, and pressure equations of state for an attractive 2D Fermi gas in the normal phase as a function of temperature and interaction strength. In 2D, interacting gases exhibit qualitatively different features to those found in 3D. This is evident in the normalized density equation of state, which peaks at intermediate densities corresponding to the crossover from classical to quantum behavior.

Industrial process surveillance system

DOEpatents

Gross, Kenneth C.; Wegerich, Stephan W.; Singer, Ralph M.; Mott, Jack E.

1998-01-01

A system and method for monitoring an industrial process and/or industrial data source. The system includes generating time varying data from industrial data sources, processing the data to obtain time correlation of the data, determining the range of data, determining learned states of normal operation and using these states to generate expected values, comparing the expected values to current actual values to identify a current state of the process closest to a learned, normal state; generating a set of modeled data, and processing the modeled data to identify a data pattern and generating an alarm upon detecting a deviation from normalcy.

Industrial process surveillance system

DOEpatents

Gross, K.C.; Wegerich, S.W.; Singer, R.M.; Mott, J.E.

1998-06-09

A system and method are disclosed for monitoring an industrial process and/or industrial data source. The system includes generating time varying data from industrial data sources, processing the data to obtain time correlation of the data, determining the range of data, determining learned states of normal operation and using these states to generate expected values, comparing the expected values to current actual values to identify a current state of the process closest to a learned, normal state; generating a set of modeled data, and processing the modeled data to identify a data pattern and generating an alarm upon detecting a deviation from normalcy. 96 figs.

Industrial Process Surveillance System

DOEpatents

Gross, Kenneth C.; Wegerich, Stephan W; Singer, Ralph M.; Mott, Jack E.

2001-01-30

A system and method for monitoring an industrial process and/or industrial data source. The system includes generating time varying data from industrial data sources, processing the data to obtain time correlation of the data, determining the range of data, determining learned states of normal operation and using these states to generate expected values, comparing the expected values to current actual values to identify a current state of the process closest to a learned, normal state; generating a set of modeled data, and processing the modeled data to identify a data pattern and generating an alarm upon detecting a deviation from normalcy.

Blocking-state influence on shot noise and conductance in quantum dots

NASA Astrophysics Data System (ADS)

Harabula, M.-C.; Ranjan, V.; Haller, R.; Fülöp, G.; Schönenberger, C.

2018-03-01

Quantum dots (QDs) investigated through electron transport measurements often exhibit varying, state-dependent tunnel couplings to the leads. Under specific conditions, weakly coupled states can result in a strong suppression of the electrical current, and they are correspondingly called blocking states. Using the combination of conductance and shot noise measurements, we investigate blocking states in carbon nanotube (CNT) QDs. We report negative differential conductance and super-Poissonian noise. The enhanced noise is the signature of electron bunching, which originates from random switches between the strongly and weakly conducting states of the QD. Negative differential conductance appears here when the blocking state is an excited state. In this case, at the threshold voltage where the blocking state becomes populated, the current is reduced. Using a master equation approach, we provide numerical simulations reproducing both the conductance and the shot noise pattern observed in our measurements.

Gene Expression Analysis of Early Stage Endometrial Cancers Reveals Unique Transcripts Associated with Grade and Histology but Not Depth of Invasion

PubMed Central

Risinger, John I.; Allard, Jay; Chandran, Uma; Day, Roger; Chandramouli, Gadisetti V. R.; Miller, Caela; Zahn, Christopher; Oliver, Julie; Litzi, Tracy; Marcus, Charlotte; Dubil, Elizabeth; Byrd, Kevin; Cassablanca, Yovanni; Becich, Michael; Berchuck, Andrew; Darcy, Kathleen M.; Hamilton, Chad A.; Conrads, Thomas P.; Maxwell, G. Larry

2013-01-01

Endometrial cancer is the most common gynecologic malignancy in the United States but it remains poorly understood at the molecular level. This investigation was conducted to specifically assess whether gene expression changes underlie the clinical and pathologic factors traditionally used for determining treatment regimens in women with stage I endometrial cancer. These include the effect of tumor grade, depth of myometrial invasion and histotype. We utilized oligonucleotide microarrays to assess the transcript expression profile in epithelial glandular cells laser microdissected from 79 endometrioid and 12 serous stage I endometrial cancers with a heterogeneous distribution of grade and depth of myometrial invasion, along with 12 normal post-menopausal endometrial samples. Unsupervised multidimensional scaling analyses revealed that serous and endometrioid stage I cancers have similar transcript expression patterns when compared to normal controls where 900 transcripts were identified to be differentially expressed by at least fourfold (univariate t-test, p < 0.001) between the cancers and normal endometrium. This analysis also identified transcript expression differences between serous and endometrioid cancers and tumor grade, but no apparent differences were identified as a function of depth of myometrial invasion. Four genes were validated by quantitative PCR on an independent set of cancer and normal endometrium samples. These findings indicate that unique gene expression profiles are associated with histologic type and grade, but not myometrial invasion among early stage endometrial cancers. These data provide a comprehensive perspective on the molecular alterations associated with stage I endometrial cancer, particularly those subtypes that have the worst prognosis. PMID:23785665

The association of obesity and school absenteeism attributed to illness or injury among adolescents in the United States, 2009.

PubMed

Pan, Liping; Sherry, Bettylou; Park, Sohyun; Blanck, Heidi M

2013-01-01

School attendance can impact academic performance. Childhood obesity-related physical and psychosocial consequences are potentially associated with school absenteeism. Thus, we examined the association between school absenteeism attributed to illness or injury and obesity among adolescents aged 12-17 years. We used a weighted sample of 3,470 U.S. adolescents from the 2009 National Health Interview Survey. School absenteeism was measured from the parent-reported number of sick days taken in the preceding 12 months. Body mass index was calculated from parent-reported weight and height. Weight status was classified based on the sex-specific body mass index-for-age percentile defined by the CDC growth charts. Poisson regression was conducted to examine the association between school absenteeism and weight status, controlling for selected sociodemographic characteristics and disease status. The mean number of annual sick days was 3.9 days overall; 3.4 days among normal-weight, 4.4 days among overweight, and 4.5 days among obese adolescents. Obese adolescents had a higher proportion of missing ≥4 days of school per year than adolescents of normal weight. Our multivariate analyses found that compared with adolescents of normal weight, overweight and obese adolescents had greater than one-third more sick days annually (rate ratio = 1.36 for overweight and 1.37 for obese adolescents). Overweight and obese adolescents had 36% and 37% more sick days, respectively, than adolescents of normal weight. The results suggest another potential aspect of obesity prevention and reduction efforts among children and families is to improve children's school attendance. Published by Elsevier Inc.

Mood state sub-types in adults who stutter: A prospective study.

PubMed

Tran, Yvonne; Blumgart, Elaine; Craig, Ashley

2018-06-01

Many adults who stutter have elevated negative mood states like anxiety and depressive mood. Little is known about how mood states change over time. The purpose of this study was to determine the trajectories or sub-types of mood states in adults who stutter over a 6 month period, and establish factors that contribute to these sub-types. Participants included 129 adults who stutter who completed an assessment regimen at baseline, including a measure of mood states (Symptom Checklist-90-Revised). Three mood states were assessed (interpersonal sensitivity or IS, depressive mood and anxiety) once a month over 6 months. Latent class growth mixture modeling was used to establish trajectories of change in these mood states over time. Logistic regression was then used to determine factors assessed at baseline that contribute to the IS trajectories. Three-class trajectory models were accepted as the best fit for IS, depressive mood and anxiety mood sub-types. Stable and normal mood state sub-types were found, incorporating around 60% of participants. Up to 40% belonged to sub-types comprising elevated levels of negative mood states. The logistic regression was conducted only with the IS domain, and revealed four factors that significantly contributed to IS mood sub-types. Those with low perceived control, low vitality, elevated social fears and being female were more likely to belong to elevated IS classes. This research revealed mood sub-types in adults who stutter, providing direction for the treatment of stuttering. Clarification of how much stuttering influences mood sub-types versus pre-existing mood is required. Copyright © 2017 Elsevier Inc. All rights reserved.

Prevalence of Central Obesity among Adults with Normal BMI and Its Association with Metabolic Diseases in Northeast China.

PubMed

Zhang, Peng; Wang, Rui; Gao, Chunshi; Jiang, Lingling; Lv, Xin; Song, Yuanyuan; Li, Bo

2016-01-01

The present study aimed to investigate the prevalence of central obesity among adults with normal BMI and its association with metabolic diseases in Jilin Province, China. A population-based cross-sectional study was conducted in 2012 in Jilin Province of China. Information was collected by face to face interview. Descriptive data analysis and 95% confidence intervals (CI) of prevalence/frequency were conducted. Log-binomial regression analyses were used to find the independent factors associated with central obesity and to explore the adjusted association between central obesity and metabolic diseases among adults with normal BMI. Among the adult residents with normal BMI in Jilin Province, 55.6% of participants with central obesity self-assessed as normal weight and 27.0% thought their body weight were above normal. 12.7% of central obesity people took methods to lose weight, while 85.3% didn't. Female, older people and non-manual worker had higher risk to be central obesity among adults with normal BMI. Hypertension, diabetes and hyperlipidemia were significantly associated with central obesity among adults with normal BMI, the PRs were 1.337 (1.224-1.461), 1.323 (1.193-1.456) and 1.261 (1.152-1.381) separately when adjusted for gender, age and BMI. Hypertension, diabetes and hyperlipidemia were significantly associated with central obesity among adults with normal BMI in Jilin Province, China. The low rates of awareness and control of central obesity among adults with normal BMI should be improved by government and health department.

Enhanced Spin Conductance of a Thin-Film Insulating Antiferromagnet

NASA Astrophysics Data System (ADS)

Bender, Scott A.; Skarsvâg, Hans; Brataas, Arne; Duine, Rembert A.

2017-08-01

We investigate spin transport by thermally excited spin waves in an antiferromagnetic insulator. Starting from a stochastic Landau-Lifshitz-Gilbert phenomenology, we obtain the out-of-equilibrium spin-wave properties. In linear response to spin biasing and a temperature gradient, we compute the spin transport through a normal-metal-antiferromagnet-normal-metal heterostructure. We show that the spin conductance diverges as one approaches the spin-flop transition; this enhancement of the conductance should be readily observable by sweeping the magnetic field across the spin-flop transition. The results from such experiments may, on the one hand, enhance our understanding of spin transport near a phase transition, and on the other be useful for applications that require a large degree of tunability of spin currents. In contrast, the spin Seebeck coefficient does not diverge at the spin-flop transition. Furthermore, the spin Seebeck coefficient is finite even at zero magnetic field, provided that the normal metal contacts break the symmetry between the antiferromagnetic sublattices.

Role of the pedunculopontine nucleus in controlling gait and sleep in normal and parkinsonian monkeys.

PubMed

Karachi, C; Francois, Chantal

2018-03-01

Patients with Parkinson's disease (PD) develop cardinal motor symptoms, including akinesia, rigidity, and tremor, that are alleviated by dopaminergic medication and/or subthalamic deep brain stimulation. Over the time course of the disease, gait and balance disorders worsen and become resistant to pharmacological and surgical treatments. These disorders generate debilitating motor symptoms leading to increased dependency, morbidity, and mortality. PD patients also experience sleep disturbance that raise the question of a common physiological basis. An extensive experimental and clinical body of work has highlighted the crucial role of the pedunculopontine nucleus (PPN) in the control of gait and sleep, and its potential major role in PD. Here, we summarise our investigations in the monkey PPN in the normal and parkinsonian states. We first examined the anatomy and connectivity of the PPN and the cuneiform nucleus which both belong to the mesencephalic locomotor region. Second, we conducted experiments to demonstrate the specific effects of PPN cholinergic lesions on locomotion in the normal and parkinsonian monkey. Third, we aimed to understand how PPN cholinergic lesions impair sleep in parkinsonian monkeys. Our final goal was to develop a novel model of advanced PD with gait and sleep disorders. We believe that this monkey model, even if it does not attempt to reproduce the exact human disease with all its complexities, represents a good biomedical model to characterise locomotion and sleep in the context of PD.

Differences in Relative Levels of 88 microRNAs in Various Regions of the Normal Adult Human Brain.

PubMed

Filatova, Elena V; Alieva, Anelya; Shadrina, Maria I; Slominsky, Petr A

2017-08-16

Since the discovery of microRNAs (miRNAs) in the 1990s, our knowledge about their biology has grown considerably. The increasing number of studies addressing the role of miRNAs in development and in various diseases emphasizes the need for a comprehensive catalogue of accurate sequence, expression and conservation information regarding the large number of miRNAs proposed recently in all organs and tissues. The objective of this study was to provide data on the levels of miRNA expression in 15 tissues of the normal human brain. We conducted an analysis of the relative levels of 88 of the most abundantly expressed and best characterized miRNA derived postmortem from well-characterized samples of various regions of the brains from five normal individuals. The cluster analysis revealed some differences in the relative levels of these miRNAs among the brain regions studied. Such diversity can be explained by different functioning of these brain regions. We hope that the data from the current study are a resource that will be useful to our colleagues in this exciting field, as more hypotheses will be generated and tested with regard to small noncoding RNA in the human brain in healthy and disease states. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Electron Transport Coefficients and Effective Ionization Coefficients in SF6-O2 and SF6-Air Mixtures Using Boltzmann Analysis

NASA Astrophysics Data System (ADS)

Wei, Linsheng; Xu, Min; Yuan, Dingkun; Zhang, Yafang; Hu, Zhaoji; Tan, Zhihong

2014-10-01

The electron drift velocity, electron energy distribution function (EEDF), density-normalized effective ionization coefficient and density-normalized longitudinal diffusion velocity are calculated in SF6-O2 and SF6-Air mixtures. The experimental results from a pulsed Townsend discharge are plotted for comparison with the numerical results. The reduced field strength varies from 40 Td to 500 Td (1 Townsend=10-17 V·cm2) and the SF6 concentration ranges from 10% to 100%. A Boltzmann equation associated with the two-term spherical harmonic expansion approximation is utilized to gain the swarm parameters in steady-state Townsend. Results show that the accuracy of the Boltzmann solution with a two-term expansion in calculating the electron drift velocity, electron energy distribution function, and density-normalized effective ionization coefficient is acceptable. The effective ionization coefficient presents a distinct relationship with the SF6 content in the mixtures. Moreover, the E/Ncr values in SF6-Air mixtures are higher than those in SF6-O2 mixtures and the calculated value E/Ncr in SF6-O2 and SF6-Air mixtures is lower than the measured value in SF6-N2. Parametric studies conducted on these parameters using the Boltzmann analysis offer substantial insight into the plasma physics, as well as a basis to explore the ozone generation process.

Assessment of Knowledge of Critical Cardiovascular Risk Indicators among College Students: Does Stage of Education Matter?

PubMed Central

Sarpong, Daniel F.; Curry, India Y.; Williams, Melinda

2017-01-01

The health risk of college students in the United States (US) is on the rise, with a significant increase in the prevalence of cardiovascular risk factors. Cardiovascular disease is the leading cause of death in the US, costing approximately $475.3 billion yearly. The goals of this “Know Your Numbers” study were to: (1) estimate the awareness of college students of their critical health numbers (CHN); and (2) compare a college of pharmacy entry class (IP1) with second semester non-commuter freshman college students (FCS) in knowing their numbers. A cross-sectional 15-item pre-test survey was conducted among a convenience sample of IP1 and FCS. All statistical tests were performed at α = 0.05. Awareness of their: cholesterol (7%), blood pressure (BP) (35%), glucose (8%), and body mass index (BMI) (42%) were low. The IP1, compared to FCS, were more knowledgeable of: (1) their BP (46% vs. 28%, p = 0.01); (2) BP normal range (74% vs. 63%, p = 0.02); and (3) BMI normal range (39% vs. 23%, p = 0.04). The IP1s maintained a healthier diet than the FCS (64% vs. 36%, p < 0.0001). Awareness of knowing CHN was very low. Knowledge of one’s CHN was significantly associated with knowledge of normal reference values for BP, glucose, and BMI. PMID:28257080

Current collectors for improved safety

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

Abdelmalak, Michael Naguib; Allu, Srikanth; Dudney, Nancy J.

A battery electrode assembly includes a current collector with conduction barrier regions having a conductive state in which electrical conductivity through the conduction barrier region is permitted, and a safety state in which electrical conductivity through the conduction barrier regions is reduced. The conduction barrier regions change from the conductive state to the safety state when the current collector receives a short-threatening event. An electrode material can be connected to the current collector. The conduction barrier regions can define electrical isolation subregions. A battery is also disclosed, and methods for making the electrode assembly, methods for making a battery, andmore » methods for operating a battery.« less

PRESSURE SENSING DEVICE

DOEpatents

Pope, K.E.

1959-12-15

This device is primarily useful as a switch which is selectively operable to actuate in response to either absolute or differential predetermined pressures. The device generally comprises a pressure-tight housing divided by a movable impermeable diaphragm into two chambers, a reference pressure chamber and a bulb chamber containing the switching means and otherwise filled with an incompressible non-conducting fluid. The switch means comprises a normally collapsed bulb having an electrically conductive outer surface and a vent tube leading to the housing exterior. The normally collapsed bulb is disposed such that upon its inflation, respensive to air inflow from the vent, two contacts fixed within the bulb chamber are adapted to be electrically shorted by the conducting outer surface of the bulb.

Descriptive Statistics for Modern Test Score Distributions: Skewness, Kurtosis, Discreteness, and Ceiling Effects.

PubMed

Ho, Andrew D; Yu, Carol C

2015-06-01

Many statistical analyses benefit from the assumption that unconditional or conditional distributions are continuous and normal. More than 50 years ago in this journal, Lord and Cook chronicled departures from normality in educational tests, and Micerri similarly showed that the normality assumption is met rarely in educational and psychological practice. In this article, the authors extend these previous analyses to state-level educational test score distributions that are an increasingly common target of high-stakes analysis and interpretation. Among 504 scale-score and raw-score distributions from state testing programs from recent years, nonnormal distributions are common and are often associated with particular state programs. The authors explain how scaling procedures from item response theory lead to nonnormal distributions as well as unusual patterns of discreteness. The authors recommend that distributional descriptive statistics be calculated routinely to inform model selection for large-scale test score data, and they illustrate consequences of nonnormality using sensitivity studies that compare baseline results to those from normalized score scales.

NMR Structural Studies of Antimicrobial Peptides: LPcin Analogs.

PubMed

Jeong, Ji-Ho; Kim, Ji-Sun; Choi, Sung-Sub; Kim, Yongae

2016-01-19

Lactophoricin (LPcin), a component of proteose peptone (113-135) isolated from bovine milk, is a cationic amphipathic antimicrobial peptide consisting of 23 amino acids. We designed a series of N- or C-terminal truncated variants, mutated analogs, and truncated mutated analogs using peptide-engineering techniques. Then, we selected three LPcin analogs of LPcin-C8 (LPcin-YK1), LPcin-T2WT6W (LPcin-YK2), and LPcin-T2WT6W-C8 (LPcin-YK3), which may have better antimicrobial activities than LPcin, and successfully expressed them in E. coli with high yield. We elucidated the 3D structures and topologies of the three LPcin analogs in membrane environments by conducting NMR structural studies. We investigated the purity of the LPcin analogs and the α-helical secondary structures by performing (1)H-(15)N 2D HSQC and HMQC-NOESY liquid-state NMR spectroscopy using protein-containing micelle samples. We measured the 3D structures and tilt angles in membranes by conducting (15)N 1D and 2D (1)H-(15)N SAMMY type solid-state NMR spectroscopy with an 800 MHz in-house-built (1)H-(15)N double-resonance solid-state NMR probe with a strip-shield coil, using protein-containing large bicelle samples aligned and confirmed by molecular-dynamics simulations. The three LPcin analogs were found to be curved α-helical structures, with tilt angles of 55-75° for normal membrane bilayers, and their enhanced activities may be correlated with these topologies. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Ultra-Wideband Millimeter-Wave Dielectric Characteristics of Freshly Excised Normal and Malignant Human Skin Tissues.

PubMed

Mirbeik-Sabzevari, Amir; Ashinoff, Robin; Tavassolian, Negar

2018-06-01

Millimeter waves have recently gained attention for the evaluation of skin lesions and the detection of skin tumors. Such evaluations heavily rely on the dielectric contrasts existing between normal and malignant skin tissues at millimeter-wave frequencies. However, current studies on the dielectric properties of normal and diseased skin tissues at these frequencies are limited and inconsistent. In this study, a comprehensive dielectric spectroscopy study is conducted for the first time to characterize the ultra-wideband dielectric properties of freshly excised normal and malignant skin tissues obtained from skin cancer patients having undergone Mohs micrographic surgeries at Hackensack University Medical Center. Measurements are conducted using a precision slim-form open-ended coaxial probe in conjunction with a millimeter-wave vector network analyzer over the frequency range of 0.5-50 GHz. A one-pole Cole-Cole model is fitted to the complex permittivity dataset of each sample. Statistically considerable contrasts are observed between the dielectric properties of malignant and normal skin tissues over the ultra-wideband millimeter-wave frequency range considered.

Orientations of dendritic growth during solidification

NASA Astrophysics Data System (ADS)

Lee, Dong Nyung

2017-03-01

Dendrites are crystalline forms which grow far from the limit of stability of the plane front and adopt an orientation which is as close as possible to the heat flux direction. Dendritic growth orientations for cubic metals, bct Sn, and hcp Zn, can be controlled by thermal conductivity, Young's modulus, and surface energy. The control factors have been elaborated. Since the dendrite is a single crystal, its properties such as thermal conductivity that influences the heat flux direction, the minimum Young's modulus direction that influences the strain energy minimization, and the minimum surface energy plane that influences the crystal/liquid interface energy minimization have been proved to control the dendritic growth direction. The dendritic growth directions of cubic metals are determined by the minimum Young's modulus direction and/or axis direction of symmetry of the minimum crystal surface energy plane. The dendritic growth direction of bct Sn is determined by its maximum thermal conductivity direction and the minimum surface energy plane normal direction. The primary dendritic growth direction of hcp Zn is determined by its maximum thermal conductivity direction and the minimum surface energy plane normal direction and the secondary dendrite arm direction of hcp Zn is normal to the primary dendritic growth direction.

Bioelectrical Signals and Ion Channels in the Modeling of Multicellular Patterns and Cancer Biophysics.

PubMed

Cervera, Javier; Alcaraz, Antonio; Mafe, Salvador

2016-02-04

Bioelectrical signals and ion channels are central to spatial patterns in cell ensembles, a problem of fundamental interest in positional information and cancer processes. We propose a model for electrically connected cells based on simple biological concepts: i) the membrane potential of a single cell characterizes its electrical state; ii) the long-range electrical coupling of the multicellular ensemble is realized by a network of gap junction channels between neighboring cells; and iii) the spatial distribution of an external biochemical agent can modify the conductances of the ion channels in a cell membrane and the multicellular electrical state. We focus on electrical effects in small multicellular ensembles, ignoring slow diffusional processes. The spatio-temporal patterns obtained for the local map of cell electric potentials illustrate the normalization of regions with abnormal cell electrical states. The effects of intercellular coupling and blocking of specific channels on the electrical patterns are described. These patterns can regulate the electrically-induced redistribution of charged nanoparticles over small regions of a model tissue. The inclusion of bioelectrical signals provides new insights for the modeling of cancer biophysics because collective multicellular states show electrical coupling mechanisms that are not readily deduced from biochemical descriptions at the individual cell level.

Bioelectrical Signals and Ion Channels in the Modeling of Multicellular Patterns and Cancer Biophysics

PubMed Central

Cervera, Javier; Alcaraz, Antonio; Mafe, Salvador

2016-01-01

Bioelectrical signals and ion channels are central to spatial patterns in cell ensembles, a problem of fundamental interest in positional information and cancer processes. We propose a model for electrically connected cells based on simple biological concepts: i) the membrane potential of a single cell characterizes its electrical state; ii) the long-range electrical coupling of the multicellular ensemble is realized by a network of gap junction channels between neighboring cells; and iii) the spatial distribution of an external biochemical agent can modify the conductances of the ion channels in a cell membrane and the multicellular electrical state. We focus on electrical effects in small multicellular ensembles, ignoring slow diffusional processes. The spatio-temporal patterns obtained for the local map of cell electric potentials illustrate the normalization of regions with abnormal cell electrical states. The effects of intercellular coupling and blocking of specific channels on the electrical patterns are described. These patterns can regulate the electrically-induced redistribution of charged nanoparticles over small regions of a model tissue. The inclusion of bioelectrical signals provides new insights for the modeling of cancer biophysics because collective multicellular states show electrical coupling mechanisms that are not readily deduced from biochemical descriptions at the individual cell level. PMID:26841954

Bioelectrical Signals and Ion Channels in the Modeling of Multicellular Patterns and Cancer Biophysics

NASA Astrophysics Data System (ADS)

Cervera, Javier; Alcaraz, Antonio; Mafe, Salvador

2016-02-01

Bioelectrical signals and ion channels are central to spatial patterns in cell ensembles, a problem of fundamental interest in positional information and cancer processes. We propose a model for electrically connected cells based on simple biological concepts: i) the membrane potential of a single cell characterizes its electrical state; ii) the long-range electrical coupling of the multicellular ensemble is realized by a network of gap junction channels between neighboring cells; and iii) the spatial distribution of an external biochemical agent can modify the conductances of the ion channels in a cell membrane and the multicellular electrical state. We focus on electrical effects in small multicellular ensembles, ignoring slow diffusional processes. The spatio-temporal patterns obtained for the local map of cell electric potentials illustrate the normalization of regions with abnormal cell electrical states. The effects of intercellular coupling and blocking of specific channels on the electrical patterns are described. These patterns can regulate the electrically-induced redistribution of charged nanoparticles over small regions of a model tissue. The inclusion of bioelectrical signals provides new insights for the modeling of cancer biophysics because collective multicellular states show electrical coupling mechanisms that are not readily deduced from biochemical descriptions at the individual cell level.

Stress evaluation of metallic material under steady state based on nonlinear critically refracted longitudinal wave

NASA Astrophysics Data System (ADS)

Mao, Hanling; Zhang, Yuhua; Mao, Hanying; Li, Xinxin; Huang, Zhenfeng

2018-06-01

This paper presents the study of applying the nonlinear ultrasonic wave to evaluate the stress state of metallic materials under steady state. The pre-stress loading method is applied to guarantee components with steady stress. Three kinds of nonlinear ultrasonic experiments based on critically refracted longitudinal wave are conducted on components which the critically refracted longitudinal wave propagates along x, x1 and x2 direction. Experimental results indicate the second and third order relative nonlinear coefficients monotonically increase with stress, and the normalized relationship is consistent with simplified dislocation models, which indicates the experimental result is logical. The combined ultrasonic nonlinear parameter is proposed, and three stress evaluation models at x direction are established based on three ultrasonic nonlinear parameters, which the estimation error is below 5%. Then two stress detection models at x1 and x2 direction are built based on combined ultrasonic nonlinear parameter, the stress synthesis method is applied to calculate the magnitude and direction of principal stress. The results show the prediction error is within 5% and the angle deviation is within 1.5°. Therefore the nonlinear ultrasonic technique based on LCR wave could be applied to nondestructively evaluate the stress of metallic materials under steady state which the magnitude and direction are included.

High power multiple wavelength diode laser stack for DPSSL application without temperature control

NASA Astrophysics Data System (ADS)

Hou, Dong; Yin, Xia; Wang, Jingwei; Chen, Shi; Zhan, Yun; Li, Xiaoning; Fan, Yingmin; Liu, Xingsheng

2018-02-01

High power diode laser stack is widely used in pumping solid-state laser for years. Normally an integrated temperature control module is required for stabilizing the output power of solid-state laser, as the output power of the solid-state laser highly depends on the emission wavelength and the wavelength shift of diode lasers according to the temperature changes. However the temperature control module is inconvenient for this application, due to its large dimension, high electric power consumption and extra adding a complicated controlling system. Furthermore, it takes dozens of seconds to stabilize the output power when the laser system is turned on. In this work, a compact hard soldered high power conduction cooled diode laser stack with multiple wavelengths is developed for stabilizing the output power of solid-state laser in a certain temperature range. The stack consists of 5 laser bars with the pitch of 0.43mm. The peak output power of each bar in the diode laser stack reaches as much as 557W and the combined lasing wavelength spectrum profile spans 15nm. The solidstate laser, structured with multiple wavelength diode laser stacks, allows the ambient temperature change of 65°C without suddenly degrading the optical performance.

Length divergence of the lattice thermal conductivity in suspended graphene nanoribbons

NASA Astrophysics Data System (ADS)

Majee, Arnab K.; Aksamija, Zlatan

2016-06-01

Thermal properties of graphene have attracted much attention, culminating in a recent measurement of its length dependence in ribbons up to 9 μ m long. In this paper, we use the improved Callaway model to solve the phonon Boltzmann transport equation while capturing both the resistive (umklapp, isotope, and edge roughness) and nonresistive (normal) contributions. We show that for lengths smaller than 100 μ m , scaling the ribbon length while keeping the width constant leads to a logarithmic divergence of thermal conductivity. The length dependence is driven primarily by a ballistic-to-diffusive transition in the in-plane (LA and TA) branches, while in the hydrodynamic regime when 10 μ m 100 μ m due to the coupling between in-plane and flexural modes. This coupling leads to renormalization of ZA phonon dispersion in the long-wavelength range, preventing further divergence of thermal conductivity. We also uncover a strong dependence on sample width, which we attribute to the interplay between nonresistive normal and diffusive edge scattering in the Poisseuille flow regime. We conclude that normal processes play a crucial role in the length and width dependence of thermal transport in graphene in the hydrodynamic regime and dictate the relative in-plane (LA+TA) to out-of-plane (ZA) contribution to transport.

Acute severe male hypo-testosteronemia affects central motor command in humans.

PubMed

Felici, Francesco; Bazzucchi, Ilenia; Sgrò, Paolo; Quinzi, Federico; Conti, Alessandra; Aversa, Antonio; Gizzi, Leonardo; Mezzullo, Marco; Romanelli, Francesco; Pasquali, Renato; Lenzi, Andrea; Di Luigi, Luigi

2016-06-01

To indirectly evaluate the effect of androgens on neuromuscular system in humans we analyzed if an induced short-term hypogonadal state (serum total testosterone-TT<2.3ng/ml) may affect central drive to skeletal muscle and/or muscle neuro-mechanical performance. We compared voluntary and electrically evoked muscle sEMG signals from biceps brachii in nine hypogonadal male volunteers (Hypo) and in ten healthy controls (Cont). Serum TT and dihydrotestosterone (DHT) were assayed. With respect to Hypo, Cont exhibited significantly higher median frequency content (MDF) at any angular velocity; normalized MDF [95.9% (SD=23.3) vs 73.8% (SD=9.3)]; muscle fiber conduction velocity (CV) from lowest to highest angular velocities; initial MDF at fatigue test [91.78Hz (SD=22.03) vs 70.94Hz (SD=11.06)] as well as was the normalized slope [-0.64 (SD=0.14 vs -0.5 (SD=0.11)]. In the non-fatigued state, Hypo showed a slower single twitches time to peak (TTP). In Cont, half relaxation time (HRT) decreased after fatigue while increased in Hypo (p<0.05 between groups). A significant correlation between both TT and dihydrotestosterone with MDF and CV was found during voluntary contractions only. A brief exposure to very low serum TT concentration in males seem to determine a reduced excitability of the NM system which, in turn, would favor a predominant recruitment of slow twitch MUs. Copyright © 2015 Elsevier Ltd. All rights reserved.

Characterization of normality of chaotic systems including prediction and detection of anomalies

NASA Astrophysics Data System (ADS)

Engler, Joseph John

Accurate prediction and control pervades domains such as engineering, physics, chemistry, and biology. Often, it is discovered that the systems under consideration cannot be well represented by linear, periodic nor random data. It has been shown that these systems exhibit deterministic chaos behavior. Deterministic chaos describes systems which are governed by deterministic rules but whose data appear to be random or quasi-periodic distributions. Deterministically chaotic systems characteristically exhibit sensitive dependence upon initial conditions manifested through rapid divergence of states initially close to one another. Due to this characterization, it has been deemed impossible to accurately predict future states of these systems for longer time scales. Fortunately, the deterministic nature of these systems allows for accurate short term predictions, given the dynamics of the system are well understood. This fact has been exploited in the research community and has resulted in various algorithms for short term predictions. Detection of normality in deterministically chaotic systems is critical in understanding the system sufficiently to able to predict future states. Due to the sensitivity to initial conditions, the detection of normal operational states for a deterministically chaotic system can be challenging. The addition of small perturbations to the system, which may result in bifurcation of the normal states, further complicates the problem. The detection of anomalies and prediction of future states of the chaotic system allows for greater understanding of these systems. The goal of this research is to produce methodologies for determining states of normality for deterministically chaotic systems, detection of anomalous behavior, and the more accurate prediction of future states of the system. Additionally, the ability to detect subtle system state changes is discussed. The dissertation addresses these goals by proposing new representational techniques and novel prediction methodologies. The value and efficiency of these methods are explored in various case studies. Presented is an overview of chaotic systems with examples taken from the real world. A representation schema for rapid understanding of the various states of deterministically chaotic systems is presented. This schema is then used to detect anomalies and system state changes. Additionally, a novel prediction methodology which utilizes Lyapunov exponents to facilitate longer term prediction accuracy is presented and compared with other nonlinear prediction methodologies. These novel methodologies are then demonstrated on applications such as wind energy, cyber security and classification of social networks.

Strain tolerant microfilamentary superconducting wire

DOEpatents

Finnemore, D.K.; Miller, T.A.; Ostenson, J.E.; Schwartzkopf, L.A.; Sanders, S.C.

1993-02-23

A strain tolerant microfilamentary wire capable of carrying superconducting currents is provided comprising a plurality of discontinuous filaments formed from a high temperature superconducting material. The discontinuous filaments have a length at least several orders of magnitude greater than the filament diameter and are sufficiently strong while in an amorphous state to withstand compaction. A normal metal is interposed between and binds the discontinuous filaments to form a normal metal matrix capable of withstanding heat treatment for converting the filaments to a superconducting state. The geometry of the filaments within the normal metal matrix provides substantial filament-to-filament overlap, and the normal metal is sufficiently thin to allow supercurrent transfer between the overlapped discontinuous filaments but is also sufficiently thick to provide strain relief to the filaments.

Feasibility and normal values of an integrated conductivity (Nanoduct™) sweat test system in healthy newborns.

PubMed

Kuehni, Claudia E; Schindler, Matthias; Mazur, Agnieszka; Malzacher, Andreas; Hornung, René; Barben, Juerg

2017-07-01

Nanoduct™ is a simple and practical sweat analysis system measuring conductivity in situ. It requires only three microlitres of sweat, making it especially applicable to newborns. We measured conductivity in 260 healthy term infants at the age of four days, and again at four weeks to determine the proportion of successful tests, test duration, and normal values for sweat conductivity in newborns. Sufficient sweat was collected in 159/260 of four-day olds (61%), and in 225/239 of four-week olds (94%). Mean (sd) test duration was 27 (5) and 25 (5) min. Mean (sd, range) conductivity was 53mmol/l (16, 8-114) at age four days, and 36 (9, 12-64) at four weeks. Determination of sweat conductivity using Nanoduct™ cannot be recommended for four-day old newborns. However, at the age of four weeks the success rate is high (94%), and conductivity values at that age are comparable to older healthy children. Copyright © 2017 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

A childbirth educator speaks out for increased advocacy for normal birth.

PubMed

Boyd, Anne

2006-01-01

Upon noting that, over the years, normal birth has become less and less a cultural norm in the United States (where cesarean births now approach 30%), a childbirth educator speaks out to say it is time for normal-birth advocates to organize in order to increase efforts at social marketing of normal birth as a cultural norm.

A Childbirth Educator Speaks Out for Increased Advocacy for Normal Birth

PubMed Central

Boyd, Anne

2006-01-01

Upon noting that, over the years, normal birth has become less and less a cultural norm in the United States (where cesarean births now approach 30%), a childbirth educator speaks out to say it is time for normal-birth advocates to organize in order to increase efforts at social marketing of normal birth as a cultural norm. PMID:17322939

Nausea in pregnancy: attitudes among pregnant women and general practitioners on treatment and pregnancy care.

PubMed

Heitmann, Kristine; Svendsen, Hans Christian; Sporsheim, Ingvild H; Holst, Lone

2016-01-01

Nausea and vomiting during pregnancy (NVP) is very common, and may have great impact on a woman's life. The aim of this study was to explore thoughts and attitudes among Norwegian pregnant women and GPs on treatment of NVP and pregnancy care. Focus-group study. Separate focus-group discussions were conducted with pregnant women and GPs. Two focus-group discussions were conducted with pregnant women and two with GPs. The GPs thought it was important to normalize NVP symptoms. However, the women felt their distress due to NVP was trivialized by the GPs. The women were sceptical towards the use of medicines while pregnant, and avoidance was sought despite being ill. The GPs appeared uncertain with respect to medical treatment of NVP, which was stated to be considered only after progression to quite severe symptoms. Sick leave seemed to be an important part of the treatment regime applied by the GPs. The women had good experiences with graded sick leave. This Norwegian study identifies attitudes among GPs and pregnant women that may act as obstacles to appropriate care for women with NVP. The pregnant women and the GPs seemed to talk at cross-purposes; GPs' normalization of the symptoms made the women feel that their distress due to NVP was trivialized by the GPs. Our results indicate that pregnant women with NVP requiring medical treatment probably need comprehensive and reassuring information about treatment options before considering using any medicines. Nausea and vomiting during pregnancy (NVP) is very common, and considered to be of clinical significance for 35% of women. While the GPs agreed on the importance of normalizing the symptoms, the women felt their distress was trivialized, and missed being properly evaluated. Both the GPs and the women showed a reluctant attitude to medical treatment of NVP. The GPs gave the impression of considering medical treatment only after progression of symptoms to becoming quite severe.

Impact of the charge density wave state in the electrodynamic response of ZrTe 3 - x Se x : Optical evidence for a pseudogap phase

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

Chinotti, M.; Ethiraj, J.; Mirri, C.

The emergence of superconductivity upon progressively suppressing the long-range, charge-density-wave (CDW) order characterizes the phase diagram of several materials of interest in the on-going solid-state physics research. Se-doped ZrTe 3 compounds provide the most recent, suitable arena in order to investigate the interplay of otherwise competing orders in layeredlike two-dimensional systems. We present an optical study of the CDW state in ZrTe 3-xSe x at selected Se dopings, based on the measurement of the reflectivity from the far-infrared up to the ultraviolet, as a function of temperature. We particularly focus our attention to the redistribution of the spectral weight, whichmore » images the impact of the CDW state within the optical conductivity across the phase diagram of the title compounds. The electrodynamic response is consistent with a scenario based on a long-range CDW condensate at low Se doping. Upon increasing the Se content, this then gives way to local, short-range order CDW segments. Thus, our spectral weight analysis reveals the presence of a pseudogap phase, as fingerprint of the CDW precursor effects and thus shaping the charge dynamics of the title compounds in their normal state, preceding the onset of superconductivity.« less

Impact of the charge density wave state in the electrodynamic response of ZrTe 3 - x Se x : Optical evidence for a pseudogap phase

DOE PAGES

Chinotti, M.; Ethiraj, J.; Mirri, C.; ...

2018-01-12

The emergence of superconductivity upon progressively suppressing the long-range, charge-density-wave (CDW) order characterizes the phase diagram of several materials of interest in the on-going solid-state physics research. Se-doped ZrTe 3 compounds provide the most recent, suitable arena in order to investigate the interplay of otherwise competing orders in layeredlike two-dimensional systems. We present an optical study of the CDW state in ZrTe 3-xSe x at selected Se dopings, based on the measurement of the reflectivity from the far-infrared up to the ultraviolet, as a function of temperature. We particularly focus our attention to the redistribution of the spectral weight, whichmore » images the impact of the CDW state within the optical conductivity across the phase diagram of the title compounds. The electrodynamic response is consistent with a scenario based on a long-range CDW condensate at low Se doping. Upon increasing the Se content, this then gives way to local, short-range order CDW segments. Thus, our spectral weight analysis reveals the presence of a pseudogap phase, as fingerprint of the CDW precursor effects and thus shaping the charge dynamics of the title compounds in their normal state, preceding the onset of superconductivity.« less

The ÖX˜ absorption of vinoxy radical revisited: Normal and Herzberg-Teller bands observed via cavity ringdown spectroscopy

NASA Astrophysics Data System (ADS)

Thomas, Phillip S.; Chhantyal-Pun, Rabi; Kline, Neal D.; Miller, Terry A.

2010-03-01

The ÖX˜ electronic absorption spectrum of vinoxy radical has been investigated using room temperature cavity ringdown spectroscopy. Analysis of the observed bands on the basis of computed vibrational frequencies and rotational envelopes reveals that two distinct types of features are present with comparable intensities. The first type corresponds to "normal" allowed electronic transitions to the origin and symmetric vibrations in the à state. The second type is interpreted in terms of excitations to asymmetric à state vibrations, which are only vibronically allowed by Herzberg-Teller coupling to the B˜ state. Results of electronic structure calculations indicate that the magnitude of the Herzberg-Teller coupling is appropriate to produce vibronically induced transitions with intensities comparable to those of the normal bands.

Multiple normalized solutions for a planar gauged nonlinear Schrödinger equation

NASA Astrophysics Data System (ADS)

Luo, Xiao

2018-06-01

We study the existence, multiplicity, quantitative property and asymptotic behavior of normalized solutions for a gauged nonlinear Schrödinger equation arising from the Chern-Simons theory Δ u + ω u +|x|^2u+ λ ( {{h^2}(| x | )}/{{{| x | ^2}}} + \\int \\limits _{| x | }^{ + ∞} {{h(s)}/s} {u^2}(s)ds) u = {| u | ^{p - 2}}u,\\quad x\\in R^2, where ω \\in R, λ >0, p>4 and h(s) = 1/2\\int \\limits _0^s {r{u^2}(r)dr} . Combining constraint minimization method and minimax principle, we prove that the problem possesses at least two normalized solutions: One is a ground state and the other is an excited state. Furthermore, the asymptotic behavior and quantitative property of the ground state are analyzed.

New generalized corresponding states correlation for surface tension of normal saturated liquids

NASA Astrophysics Data System (ADS)

Yi, Huili; Tian, Jianxiang

2015-08-01

A new simple correlation based on the principle of corresponding state is proposed to estimate the temperature-dependent surface tension of normal saturated liquids. The new correlation contains three coefficients obtained by fitting 17,051 surface tension data of 38 saturated normal liquids. These 38 liquids contain refrigerants, hydrocarbons and some other inorganic liquids. The new correlation requires only the triple point temperature, triple point surface tension and critical point temperature as input and is able to well represent the experimental surface tension data for each of the 38 saturated normal liquids from the triple temperature up to the point near the critical point. The new correlation gives absolute average deviations (AAD) values below 3% for all of these 38 liquids with the only exception being octane with AAD=4.30%. Thus, the new correlation gives better overall results in comparison with other correlations for these 38 normal saturated liquids.

Spectroscopic study of hafnium silicate alloys prepared by RPECVD: Comparisons between conduction/valence band offset energies and optical band gaps

NASA Astrophysics Data System (ADS)

Hong, Joon Goo

Aggressive scaling of devices has continued to improve MOSFET transistor performance. As lateral device dimensions continue to decrease, gate oxide thickness must be scaled down. As one of the promising high k alternative gate oxide materials, HfO2 and its silicates were investigated to understand their direct tunneling behavior by studying band offset energies with spectroscopy and electrical characterization. Local bonding change of remote plasma deposited (HfO2)x(SiO 2)1-x alloys were characterized by Fourier transform infrared (FTIR) spectroscopy, x-ray photoelectron spectroscopy (XPS), and Auger electron spectroscopy (AES) as a function of alloy composition, x. Two different precursors with Hf Nitrato and Hf-tert-butoxide were tested to have amorphous deposition. Film composition was determined off-line by Rutherford backscattering spectroscopy (RBS) and these results were calibrated with on-line AES. As deposited Hf-silicate alloys were characterized by off-line XPS and AES for their chemical shifts interpreting with a partial charge transfer model as well as coordination changes. Sigmoidal dependence of valence band offset energies was observed. Hf 5d* state is fixed at the bottom of the conduction band and located at 1.3 +/- 0.2 eV above the top of the Si conduction band as a conduction band offset by x-ray absorption spectroscopy (XAS). Optical band gap energy changes were observed with vacuum ultra violet spectroscopic ellipsometry (VUVSE) to verify compositional dependence of conduction and valence band offset energy changes. 1 nm EOT normalized tunneling current with Wentzel-Kramer-Brillouin (WKB) simulation based on the band offset study and Franz two band model showed the minimum at the intermediate composition matching with the experimental data. Non-linear trend in tunneling current was observed because the increases in physical thickness were mitigated by reductions in band offset energies and effective mass for tunneling. C-V curves were compared to each other, and more hysteresis was observed with increasing x. Localized Hf 5d* state as a trap site was the reason for hysteresis and its reverse direction with temperature-dependent C-V curves. Temperature-dependent I-V study located Hf 5d* state. For the integration issue, nitridation study was done at the interface and surface, and both. Interfacial nitridaion gave more effective reduction in EOT.

Lack of harmonization in sweat testing for cystic fibrosis - a national survey.

PubMed

Christiansen, Anne Lindegaard; Nybo, Mads

2014-11-01

Sweat testing is used in the diagnosis of cystic fibrosis. Interpretation of the sweat test depends, however, on the method performed since conductivity, osmolality and chloride concentration all can be measured as part of a sweat test. The aim of this study was to investigate how performance of the test is organized in Denmark. Departments conducting the sweat test were contacted and interviewed following a premade questionnaire. They were asked about methods performed, applied NPU (Nomenclature for Properties and Units) code, reference interval, recommended interpretation and referred literature. 14 departments performed the sweat test. One department measured chloride and sodium concentration, while 13 departments measured conductivity. One department used a non-existing NPU code, two departments applied NPU codes inconsistent with the method performed, four departments applied no NPU code and seven applied a correct NPU code. Ten of the departments measuring conductivity applied reference intervals. Nine departments measuring conductivity had recommendations of a normal area, a grey zone and a pathological value, while four departments only applied a normal and grey zone or a pathological value. Cut-off values for normal, grey and pathological areas were like the reference intervals inconsistent. There is inconsistent use of NPU codes, reference intervals and interpretation of sweat conductivity used in the process of diagnosing cystic fibrosis. Because diagnosing cystic fibrosis is a combined effort between local pediatric departments, biochemical and genetic departments and cystic fibrosis centers, a national harmonization is necessary to assure correct clinical use.

Relationship between anisotropies of permeability, electrical conductivity, and dielectric permittivity, with application to the Ellenburger dolomite reservoir analog

NASA Astrophysics Data System (ADS)

Kutemi, Titilope F.

The steady-state flow technique was employed to measure the flow rate of clean dry air through thirty core plugs (approximately 1" diameter) of the Ellenburger dolomite, drilled normal and parallel to the dominant fractures. Porosity was estimated by the method of imbibition. Electrical parameters (electrical conductivity and dielectric permittivity) were calculated from electrical resistance and capacitance measured as a function of frequency (100 Hz, 120 Hz, 1 KHz, and 10 KHz) and saturation (dry/ambient and brine saturated conditions). Another set of permeability data obtained by the method of pressure decay on similar samples was used for correlation. Anisotropies of permeability and electromagnetic parameters were established. Empirical relations between porosity (phi), permeability (k), electrical conductivity (sigma), and dielectric permittivity (epsilon) were defined via cross-plots and linear regressions. Prediction of k from sigma and epsilon was attempted; k from sigma was modeled from a combination of the Archie's relation and the Carman-Kozeny relation. Anisotropic EM responses are sensitive to saturation. Anisotropies of conductivity and permeability were observed to be controlled by the pore micro-structure. Although the rock is fractured, the fracture density appears insufficient to dominate the effects of primary structures in these samples of the Ellenburger dolomite. Model-based prediction of permeability from conductivity is generally unreliable, and is attributed to the underlying assumptions of the models, which are not consistent with the properties of the samples used for this study. Permeability was not predictable from dielectric permittivity.

Increased androgen response to follicle-stimulating hormone administration in women with polycystic ovary syndrome.

PubMed

Wachs, Deborah S; Coffler, Mickey S; Malcom, Pamela J; Shimasaki, Shunichi; Chang, R Jeffrey

2008-05-01

In women with polycystic ovary syndrome (PCOS), excess ovarian androgen production is driven by increased LH secretion. Studies conducted in animals suggest that the granulosa cell may influence LH-stimulated theca cell androgen production. The objective of this study was to determine whether FSH enhances androgen production in women with PCOS compared with that of normal women. A prospective study was conducted to compare androgen production in response to FSH in two groups of women. The study was conducted in a General Clinical Research Center in a tertiary academic medical center. Women with PCOS, 18-35 yr (n = 20), and normal ovulatory controls, 18-35 yr (n = 10), were recruited for study. Serial blood samples were obtained over a 24-h period after an iv injection of recombinant human FSH (150 IU). The main outcome measures were serum 17-hydroxyprogesterone (17-OHP), androstenedione (A), dehydroepiandrosterone (DHEA), testosterone (T), and inhibin B (Inh B) responses after FSH administration. Basal serum 17-OHP, A, and T levels were markedly increased in women with PCOS compared with that observed in normal women. Basal DHEA and Inh B levels were similar to those of normal controls. After FSH injection, PCOS women demonstrated enhanced production of 17-OHP, A, DHEA, and Inh B, whereas in normal women no increases were observed. T levels declined slightly in both groups. These findings provide evidence that, in PCOS women, theca cell androgen production is enhanced by FSH administration and suggest a granulosa-theca cell paracrine mechanism.

Influence of disorder on the superconducting critical temperature in indium-opal nanocomposites

NASA Astrophysics Data System (ADS)

Zakharchuk, I.; Januzaj, A.; Mikhailin, N. Yu.; Traito, K. B.; Chernyaev, A. V.; Romanov, S. G.; Safonchik, M.; Shamshur, D. V.; Lähderanta, E.

2018-06-01

Transport properties of bulk indium-opal and indium-porous glass superconducting nanocomposites possessing moderate and strong disorder are investigated. A strongly nonmonotonous dependence of the global critical temperature Tc versus normal state conductivity of samples is found. The maximum, which is observed at moderate disorder, has Tc higher than that of clean bulk indium. The increasing part can be explained by the Eliashberg equations with disorder and an additional mechanism of interaction between superconducting and dielectric granules. The descending part of the maximum at higher disorder can be explained by the increasing of long-range Coulomb repulsion due to diffusion of charges. Negative slope in magnetic field dependence of resistivity and a peak in the temperature dependence of resistivity, observed in the sample near the proximity to the disorder-induced superconductor-insulator transition (SIT). A large difference between the onset temperature of superconducting fluctuations, Tcon , and global critical temperature Tc is found and considered in the framework of the weak multifractal theory. Slow time-logarithmic relaxation of the resistivity between Tc and Tcon is observed, which assumes existence of the precursor state near the SIT. This unusual state is discussed in the scope of the many-body localization theory.

Bifurcation analysis of a delay reaction-diffusion malware propagation model with feedback control

NASA Astrophysics Data System (ADS)

Zhu, Linhe; Zhao, Hongyong; Wang, Xiaoming

2015-05-01

With the rapid development of network information technology, information networks security has become a very critical issue in our work and daily life. This paper attempts to develop a delay reaction-diffusion model with a state feedback controller to describe the process of malware propagation in mobile wireless sensor networks (MWSNs). By analyzing the stability and Hopf bifurcation, we show that the state feedback method can successfully be used to control unstable steady states or periodic oscillations. Moreover, formulas for determining the properties of the bifurcating periodic oscillations are derived by applying the normal form method and center manifold theorem. Finally, we conduct extensive simulations on large-scale MWSNs to evaluate the proposed model. Numerical evidences show that the linear term of the controller is enough to delay the onset of the Hopf bifurcation and the properties of the bifurcation can be regulated to achieve some desirable behaviors by choosing the appropriate higher terms of the controller. Furthermore, we obtain that the spatial-temporal dynamic characteristics of malware propagation are closely related to the rate constant for nodes leaving the infective class for recovered class and the mobile behavior of nodes.

Perceived Body Image, Eating Behavior, and Sedentary Activities and Body Mass Index Categories in Kuwaiti Female Adolescents.

PubMed

Shaban, Lemia H; Vaccaro, Joan A; Sukhram, Shiryn D; Huffman, Fatma G

2016-01-01

Background. The State of Kuwait has a growing obesity epidemic in both genders and all age groups; however, obesity rates in the young seem to be rising. Methods. We conducted a cross-sectional survey in 169 Kuwaiti female adolescents attending both private and public schools spanning the six governorates in the State of Kuwait in order to explore female adolescents' self-image, body dissatisfaction, type of school (private versus public), TV viewing, and computer games and their relationship to body mass index. Results. Approximately half the students classified as obese perceived their body image to lie in the normal range. Females in the obese category were the most dissatisfied with their body image, followed by those in the overweight category. Eating behavior, level of physical activity, school type, television viewing, computer/video usage, and desired BMI were not significantly associated with level of obesity. Conclusion. This study was one of the few studies to assess adolescent females' body image dissatisfaction in relation to obesity in the State of Kuwait. The results suggest that including body image dissatisfaction awareness into obesity prevention programs would be of value.

Forecasting United States heartworm Dirofilaria immitis prevalence in dogs.

PubMed

Bowman, Dwight D; Liu, Yan; McMahan, Christopher S; Nordone, Shila K; Yabsley, Michael J; Lund, Robert B

2016-10-10

This paper forecasts next year's canine heartworm prevalence in the United States from 16 climate, geographic and societal factors. The forecast's construction and an assessment of its performance are described. The forecast is based on a spatial-temporal conditional autoregressive model fitted to over 31 million antigen heartworm tests conducted in the 48 contiguous United States during 2011-2015. The forecast uses county-level data on 16 predictive factors, including temperature, precipitation, median household income, local forest and surface water coverage, and presence/absence of eight mosquito species. Non-static factors are extrapolated into the forthcoming year with various statistical methods. The fitted model and factor extrapolations are used to estimate next year's regional prevalence. The correlation between the observed and model-estimated county-by-county heartworm prevalence for the 5-year period 2011-2015 is 0.727, demonstrating reasonable model accuracy. The correlation between 2015 observed and forecasted county-by-county heartworm prevalence is 0.940, demonstrating significant skill and showing that heartworm prevalence can be forecasted reasonably accurately. The forecast presented herein can a priori alert veterinarians to areas expected to see higher than normal heartworm activity. The proposed methods may prove useful for forecasting other diseases.

Efficient implementation of a real-time estimation system for thalamocortical hidden Parkinsonian properties

NASA Astrophysics Data System (ADS)

Yang, Shuangming; Deng, Bin; Wang, Jiang; Li, Huiyan; Liu, Chen; Fietkiewicz, Chris; Loparo, Kenneth A.

2017-01-01

Real-time estimation of dynamical characteristics of thalamocortical cells, such as dynamics of ion channels and membrane potentials, is useful and essential in the study of the thalamus in Parkinsonian state. However, measuring the dynamical properties of ion channels is extremely challenging experimentally and even impossible in clinical applications. This paper presents and evaluates a real-time estimation system for thalamocortical hidden properties. For the sake of efficiency, we use a field programmable gate array for strictly hardware-based computation and algorithm optimization. In the proposed system, the FPGA-based unscented Kalman filter is implemented into a conductance-based TC neuron model. Since the complexity of TC neuron model restrains its hardware implementation in parallel structure, a cost efficient model is proposed to reduce the resource cost while retaining the relevant ionic dynamics. Experimental results demonstrate the real-time capability to estimate thalamocortical hidden properties with high precision under both normal and Parkinsonian states. While it is applied to estimate the hidden properties of the thalamus and explore the mechanism of the Parkinsonian state, the proposed method can be useful in the dynamic clamp technique of the electrophysiological experiments, the neural control engineering and brain-machine interface studies.

Observation of van Hove singularity and quasiparticle interference in KFe2 As2 superconductors revealed by STM/STS measurements

NASA Astrophysics Data System (ADS)

Wen, Hai-Hu; Fang, Delong; Du, Zengyi; Wang, Zhenyu; Yang, Huan; Ding, Xiaxin

2015-03-01

We have conducted STM/STS investigations on the KFe2As2 superconducting single crystals down to 0.45 K under magnetic field. Clear electronic standing waves have been observed allowing us to investigate the quasiparticle interference (QPI). Interestingly we observed a sharp peak of local density of states (LDOS) near the Fermi energy showing evidence of strongly enhanced DOS both below and above Tc. We demonstrate that this is induced by a van Hove singularity with the saddle point locating only 4 meV below the Fermi energy. Below Tc it is found that only 20% of the normal state DOS is gapped away by superconductivity, with the major part of DOS due to VHS ungapped. Combing with the ARPES data, we find that the VHS points locate on the (π,0) point, which gives strong constraint on the gap function and pairing mechanism. In the mixed state we clearly observed the mixture of vortices and the standing waves due to quasiparticle interference, giving support to above picture. In collaboration with X. Shi, P. Richard, T. Qian and H. Ding et al. in Institute of Physics, CAS.

Microwave Conductivity of Laser Ablated YBa2Cu3O7-delta Superconducting Films and Its Relation to Microstrip Transmission Line Performance

NASA Technical Reports Server (NTRS)

Bhasin, K. B.; Warner, J. D.; Chorey, C. M.; Ebihara, B. T.; Romanofsky, R. R.; Heinen, V. O.

1990-01-01

We report on the values of the microwave conductivity in the normal (sigma(subN)) and superconducting (sigma*=sigma(sub1)-j sigma(sub2)) states of two laser ablated YBa2CU3O7(sigma) thin films at 35 GHz, in the temperature range from 20 to 300 K. The films 0.7 and 0.4 micrometers) were deposited on LaA10(sub3) by laser ablation. The conductivity was obtained from the microwave power transmitted through the films and assuming a two-fluid model. Values of sigma(subN) approximately 2.3 X 10(exp5) S/m at room temperature for both films, and of sigma(sub1) approximately 6.3 X 10(exp5) and 4.6 X 10(exp5) S/m at temperatures around 80 K were obtained for the 0.7 and 0.4 micrometer films respectively. For sigma(sub2) values of 4.9 X 10(exp6) and 5.4 X 10(exp6) S/m were obtained for the 0.7 and 0.4 micrometer films at 80 K. The expected conductor losses and Q-factor of a superconducting ring resonator were calculated using these conductivity values. The theoretical values were then compared with the experimental results obtained for a resonator fabricated from one of these films.

The composition and stability of the vaginal microbiota of normal pregnant women is different from that of non-pregnant women

PubMed Central

2014-01-01

Background This study was undertaken to characterize the vaginal microbiota throughout normal human pregnancy using sequence-based techniques. We compared the vaginal microbial composition of non-pregnant patients with a group of pregnant women who delivered at term. Results A retrospective case–control longitudinal study was designed and included non-pregnant women (n = 32) and pregnant women who delivered at term (38 to 42 weeks) without complications (n = 22). Serial samples of vaginal fluid were collected from both non-pregnant and pregnant patients. A 16S rRNA gene sequence-based survey was conducted using pyrosequencing to characterize the structure and stability of the vaginal microbiota. Linear mixed effects models and generalized estimating equations were used to identify the phylotypes whose relative abundance was different between the two study groups. The vaginal microbiota of normal pregnant women was different from that of non-pregnant women (higher abundance of Lactobacillus vaginalis, L. crispatus, L. gasseri and L. jensenii and lower abundance of 22 other phylotypes in pregnant women). Bacterial community state type (CST) IV-B or CST IV-A characterized by high relative abundance of species of genus Atopobium as well as the presence of Prevotella, Sneathia, Gardnerella, Ruminococcaceae, Parvimonas, Mobiluncus and other taxa previously shown to be associated with bacterial vaginosis were less frequent in normal pregnancy. The stability of the vaginal microbiota of pregnant women was higher than that of non-pregnant women; however, during normal pregnancy, bacterial communities shift almost exclusively from one CST dominated by Lactobacillus spp. to another CST dominated by Lactobacillus spp. Conclusion We report the first longitudinal study of the vaginal microbiota in normal pregnancy. Differences in the composition and stability of the microbial community between pregnant and non-pregnant women were observed. Lactobacillus spp. were the predominant members of the microbial community in normal pregnancy. These results can serve as the basis to study the relationship between the vaginal microbiome and adverse pregnancy outcomes. PMID:24484853

Effect of surrogate aggregates on the thermal conductivity of concrete at ambient and elevated temperatures.

PubMed

Yun, Tae Sup; Jeong, Yeon Jong; Youm, Kwang-Soo

2014-01-01

The accurate assessment of the thermal conductivity of concretes is an important part of building design in terms of thermal efficiency and thermal performance of materials at various temperatures. We present an experimental assessment of the thermal conductivity of five thermally insulated concrete specimens made using lightweight aggregates and glass bubbles in place of normal aggregates. Four different measurement methods are used to assess the reliability of the thermal data and to evaluate the effects of the various sensor types. The concrete specimens are also assessed at every 100 °C during heating to ~800 °C. Normal concrete is shown to have a thermal conductivity of ~2.25 W m(-1) K(-1). The surrogate aggregates effectively reduce the conductivity to ~1.25 W m(-1) K(-1) at room temperature. The aggregate size is shown not to affect thermal conduction: fine and coarse aggregates each lead to similar results. Surface contact methods of assessment tend to underestimate thermal conductivity, presumably owing to high thermal resistance between the transducers and the specimens. Thermogravimetric analysis shows that the stages of mass loss of the cement paste correspond to the evolution of thermal conductivity upon heating.

Effect of Surrogate Aggregates on the Thermal Conductivity of Concrete at Ambient and Elevated Temperatures

PubMed Central

Yun, Tae Sup; Jeong, Yeon Jong; Youm, Kwang-Soo

2014-01-01

The accurate assessment of the thermal conductivity of concretes is an important part of building design in terms of thermal efficiency and thermal performance of materials at various temperatures. We present an experimental assessment of the thermal conductivity of five thermally insulated concrete specimens made using lightweight aggregates and glass bubbles in place of normal aggregates. Four different measurement methods are used to assess the reliability of the thermal data and to evaluate the effects of the various sensor types. The concrete specimens are also assessed at every 100°C during heating to ~800°C. Normal concrete is shown to have a thermal conductivity of ~2.25 W m−1 K−1. The surrogate aggregates effectively reduce the conductivity to ~1.25 W m−1 K−1 at room temperature. The aggregate size is shown not to affect thermal conduction: fine and coarse aggregates each lead to similar results. Surface contact methods of assessment tend to underestimate thermal conductivity, presumably owing to high thermal resistance between the transducers and the specimens. Thermogravimetric analysis shows that the stages of mass loss of the cement paste correspond to the evolution of thermal conductivity upon heating. PMID:24696666

Superconducting and normal-state anisotropy of the doped topological insulator Sr 0.1Bi 2Se 3

DOE PAGES

Smylie, M. P.; Willa, K.; Claus, H.; ...

2018-05-16

Sr xBi 2Se 3 and the related compounds Cu xBi 2Se 3 and Nb xBi 2Se 3 have attracted considerable interest, as these materials may be realizations of unconventional topological superconductors. Superconductivity with T c ~3 K in Sr xBi 2Se 3 arises upon intercalation of Sr into the layered topological insulator Bi 2Se 3. Here we elucidate the anisotropy of the normal and superconducting state of Sr 0.1Bi 2Se 3 with angular dependent magnetotransport and thermodynamic measurements. High resolution x-ray diffraction studies underline the high crystalline quality of the samples. We demonstrate that the normal state electronic and magneticmore » properties of Sr 0.1Bi 2Se 3 are isotropic in the basal plane while we observe a large two-fold in-plane anisotropy of the upper critical field in the superconducting state. In conclusion, our results support the recently proposed odd-parity nematic state characterized by a nodal gap of Eu symmetry in Sr xBi 2Se 3.« less

Superconducting and normal-state anisotropy of the doped topological insulator Sr 0.1Bi 2Se 3

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

Smylie, M. P.; Willa, K.; Claus, H.

Sr xBi 2Se 3 and the related compounds Cu xBi 2Se 3 and Nb xBi 2Se 3 have attracted considerable interest, as these materials may be realizations of unconventional topological superconductors. Superconductivity with T c ~3 K in Sr xBi 2Se 3 arises upon intercalation of Sr into the layered topological insulator Bi 2Se 3. Here we elucidate the anisotropy of the normal and superconducting state of Sr 0.1Bi 2Se 3 with angular dependent magnetotransport and thermodynamic measurements. High resolution x-ray diffraction studies underline the high crystalline quality of the samples. We demonstrate that the normal state electronic and magneticmore » properties of Sr 0.1Bi 2Se 3 are isotropic in the basal plane while we observe a large two-fold in-plane anisotropy of the upper critical field in the superconducting state. In conclusion, our results support the recently proposed odd-parity nematic state characterized by a nodal gap of Eu symmetry in Sr xBi 2Se 3.« less

Competitive Dynamics on Complex Networks

PubMed Central

Zhao, Jiuhua; Liu, Qipeng; Wang, Xiaofan

2014-01-01

We consider a dynamical network model in which two competitors have fixed and different states, and each normal agent adjusts its state according to a distributed consensus protocol. The state of each normal agent converges to a steady value which is a convex combination of the competitors' states, and is independent of the initial states of agents. This implies that the competition result is fully determined by the network structure and positions of competitors in the network. We compute an Influence Matrix (IM) in which each element characterizing the influence of an agent on another agent in the network. We use the IM to predict the bias of each normal agent and thus predict which competitor will win. Furthermore, we compare the IM criterion with seven node centrality measures to predict the winner. We find that the competitor with higher Katz Centrality in an undirected network or higher PageRank in a directed network is most likely to be the winner. These findings may shed new light on the role of network structure in competition and to what extent could competitors adjust network structure so as to win the competition. PMID:25068622

[Trace and anxiety of nursing mothers with insufficient and normal breast feeding indicators].

PubMed

Aragaki, Ilva Marico Mizumoto; Silva, Isília Aparecida; dos Santos, Jair Lício Ferreira

2006-09-01

The objective of this study was to identify and compare the trace and the anxiety state on the 10th day postpartum and the anxiety state on the 30th day postpartum of primiparous and multiparous nursing mothers who present insufficient breast feeding indicators and nursing mothers with normal breast feeding, in order to verify the possible relationships between the anxiety state of the nursing mothers in those two moments with the insufficient breast feeding indicators presented. This is an exploratory and descriptive study, whose data has been gotten from 168 nursing mothers and their children by means of interviews in nursing consultations in the 10th and 30th day postpartum. The results obtained showed that primiparous and multiparous with insufficient breast feeding and primiparous with normal lactation presented higher anxiety state trace than the anxiety state on the 10th and 30th day postpartum. There was remission of the maternal signals of anxiety with the passing of time, which may be caused by the correction of the breast feeding technique and support to the nursing mothers.

Superconducting and normal-state anisotropy of the doped topological insulator Sr0.1Bi2Se3.

PubMed

Smylie, M P; Willa, K; Claus, H; Koshelev, A E; Song, K W; Kwok, W-K; Islam, Z; Gu, G D; Schneeloch, J A; Zhong, R D; Welp, U

2018-05-16

Sr x Bi 2 Se 3 and the related compounds Cu x Bi 2 Se 3 and Nb x Bi 2 Se 3 have attracted considerable interest, as these materials may be realizations of unconventional topological superconductors. Superconductivity with T c  ~3 K in Sr x Bi 2 Se 3 arises upon intercalation of Sr into the layered topological insulator Bi 2 Se 3 . Here we elucidate the anisotropy of the normal and superconducting state of Sr 0.1 Bi 2 Se 3 with angular dependent magnetotransport and thermodynamic measurements. High resolution x-ray diffraction studies underline the high crystalline quality of the samples. We demonstrate that the normal state electronic and magnetic properties of Sr 0.1 Bi 2 Se 3 are isotropic in the basal plane while we observe a large two-fold in-plane anisotropy of the upper critical field in the superconducting state. Our results support the recently proposed odd-parity nematic state characterized by a nodal gap of Eu symmetry in Sr x Bi 2 Se 3 .

Reliable multicast protocol specifications protocol operations

NASA Technical Reports Server (NTRS)

Callahan, John R.; Montgomery, Todd; Whetten, Brian

1995-01-01

This appendix contains the complete state tables for Reliable Multicast Protocol (RMP) Normal Operation, Multi-RPC Extensions, Membership Change Extensions, and Reformation Extensions. First the event types are presented. Afterwards, each RMP operation state, normal and extended, is presented individually and its events shown. Events in the RMP specification are one of several things: (1) arriving packets, (2) expired alarms, (3) user events, (4) exceptional conditions.

Decay hazard (Scheffer) index values calculated from 1971-2000 climate normal data

Treesearch

Charles G. Carll

2009-01-01

Climate index values for estimating decay hazard to wood exposed outdoors above ground (commonly known as Scheffer index values) were calculated for 280 locations in the United States (270 locations in the conterminous United States) using the most current climate normal data available from the National Climatic Data Center. These were data for the period 1971–2000. In...

Where did the time go? Friction evolves with slip following large velocity steps, normal stress steps, and (?) during long holds

NASA Astrophysics Data System (ADS)

Rubin, A. M.; Bhattacharya, P.; Tullis, T. E.; Okazaki, K.; Beeler, N. M.

2016-12-01

The popular constitutive formulations of rate-and-state friction offer two end-member views on whether friction evolves only with slip (Slip law state evolution) or with time even without slip (Aging law state evolution). While rate stepping experiments show support for the Slip law, laboratory observed frictional behavior of initially bare rock surfaces near zero slip rate has traditionally been interpreted to show support for time-dependent evolution of frictional strength. Such laboratory derived support for time-dependent evolution has been one of the motivations behind the Aging law being widely used to model earthquake cycles on natural faults.Through a combination of theoretical results and new experimental data on initially bare granite, we show stronger support for the other end member view, i.e. that friction under a wide range of sliding conditions evolves only with slip. Our dataset is unique in that it combines up to 3.5 orders of magnitude rate steps, sequences of holds up to 10000s, and 5% normal stress steps at order of magnitude different sliding rates during the same experimental run. The experiments were done on the Brown rotary shear apparatus using servo feedback, making the machine stiff enough to provide very large departures from steady-state while maintaining stable, quasi-static sliding. Across these diverse sliding conditions, and in particular for both large velocity step decreases and the longest holds, the data are much more consistent with the Slip law version of slip-dependence than the time-dependence formulated in the Aging law. The shear stress response to normal stress steps is also consistently better explained by the Slip law when paired with the Linker-Dieterich type response to normal stress perturbations. However, the remarkable symmetry and slip-dependence of the normal stress step increases and decreases suggest deficiencies in the Linker-Dieterich formulation that we will probe in future experiments.High quality measurements of interface compaction from the normal-stress steps suggest that the instantaneous changes in state and contact area are opposite in sign, indicating that state evolution might be fundamentally connected to contact quality, and not quantity alone.

Normalizing English Language Learner Students: A Foucauldian Analysis of Opposition to Bilingual Education

ERIC Educational Resources Information Center

Bondy, Jennifer M.

2011-01-01

This article uses Foucault's (1977/1995) concept of normalization to analyze contemporary opposition to bilingual education in the United States. These contemporary movements have "normalized" English language learner (ELL) students by appropriating the technology of language in order to become "Americanized." This has become…

Personality and antisocial behavior in children and adolescents: an enquiry into Eysenck's and Gray's theories.

PubMed

Fonseca, A C; Yule, W

1995-12-01

Two studies were conducted to test the hypotheses derived from Eysenck's and Gray's theories of personality regarding antisocial behavior. For this purpose the Eysenck Personality Questionnaire (Junior) (EPQ-Junior) and a card task aimed at measuring sensitivity to reward were used in each of the studies. The first study compared a group of juvenile delinquents with a group of nondelinquents and the second study compared a group of severely conduct-disordered children with a group of normal children. The results did not support Eysenck's claim that delinquents score higher than their normal counterparts on extraversion, neuroticism, and psychoticism. Some support was found for the hypothesis derived from Gray's theory: Children and adolescents with severe antisocial behavior were more sensitive to rewards than their normal counterparts.

Signatures of the Mott transition in the antiferromagnetic state of the two-dimensional Hubbard model

DOE PAGES

Fratino, L.; Sémon, P.; Charlebois, M.; ...

2017-06-06

The properties of a phase with large correlation length can be strongly influenced by the underlying normal phase. Here, we illustrate this by studying the half-filled two-dimensional Hubbard model using cellular dynamical mean-field theory with continuous-time quantum Monte Carlo. Sharp crossovers in the mechanism that favors antiferromagnetic correlations and in the corresponding local density of states are observed. We found that these crossovers occur at values of the interaction strength U and temperature T that are controlled by the underlying normal-state Mott transition.

Proposal: A Hybrid Dictionary Modelling Approach for Malay Tweet Normalization

NASA Astrophysics Data System (ADS)

Muhamad, Nor Azlizawati Binti; Idris, Norisma; Arshi Saloot, Mohammad

2017-02-01

Malay Twitter message presents a special deviation from the original language. Malay Tweet widely used currently by Twitter users, especially at Malaya archipelago. Thus, it is important to make a normalization system which can translated Malay Tweet language into the standard Malay language. Some researchers have conducted in natural language processing which mainly focuses on normalizing English Twitter messages, while few studies have been done for normalize Malay Tweets. This paper proposes an approach to normalize Malay Twitter messages based on hybrid dictionary modelling methods. This approach normalizes noisy Malay twitter messages such as colloquially language, novel words, and interjections into standard Malay language. This research will be used Language Model and N-grams model.

Progress Toward Steady State Tokamak Operation Exploiting the high bootstrap current fraction regime

NASA Astrophysics Data System (ADS)

Ren, Q.

2015-11-01

Recent DIII-D experiments have advanced the normalized fusion performance of the high bootstrap current fraction tokamak regime toward reactor-relevant steady state operation. The experiments, conducted by a joint team of researchers from the DIII-D and EAST tokamaks, developed a fully noninductive scenario that could be extended on EAST to a demonstration of long pulse steady-state tokamak operation. Fully noninductive plasmas with extremely high values of the poloidal beta, βp >= 4 , have been sustained at βT >= 2 % for long durations with excellent energy confinement quality (H98y,2 >= 1 . 5) and internal transport barriers (ITBs) generated at large minor radius (>= 0 . 6) in all channels (Te, Ti, ne, VTf). Large bootstrap fraction (fBS ~ 80 %) has been obtained with high βp. ITBs have been shown to be compatible with steady state operation. Because of the unusually large ITB radius, normalized pressure is not limited to low βN values by internal ITB-driven modes. βN up to ~4.3 has been obtained by optimizing the plasma-wall distance. The scenario is robust against several variations, including replacing some on-axis with off-axis neutral beam injection (NBI), adding electron cyclotron (EC) heating, and reducing the NBI torque by a factor of 2. This latter observation is particularly promising for extension of the scenario to EAST, where maximum power is obtained with balanced NBI injection, and to a reactor, expected to have low rotation. However, modeling of this regime has provided new challenges to state-of-the-art modeling capabilities: quasilinear models can dramatically underpredict the electron transport, and the Sauter bootstrap current can be insufficient. The analysis shows first-principle NEO is in good agreement with experiments for the bootstrap current calculation and ETG modes with a larger saturated amplitude or EM modes may provide the missing electron transport. Work supported in part by the US DOE under DE-FC02-04ER54698, DE-AC52-07NA27344, DE-AC02-09CH11466, and the NMCFP of China under 2015GB110000 and 2015GB102000.

Neuromuscular ultrasound in patients with carpal tunnel syndrome and normal nerve conduction studies.

PubMed

Aseem, Fazila; Williams, Jessica W; Walker, Francis O; Cartwright, Michael S

2017-06-01

Nerve conduction studies (NCS) are sensitive for carpal tunnel syndrome (CTS), but a small proportion of patients with clinical CTS have normal NCS. This retrospective study was designed to assess the neuromuscular ultrasound findings in a group of CTS patients. The electronic medical record was reviewed by a neurologist to identify patients who had a diagnosis of CTS with normal NCS, including either mixed median-ulnar comparison or transcarpal sensory studies, and complete neuromuscular ultrasound evaluation for CTS. Fourteen individuals (22 wrists) met all criteria. A total of 92.3% had median nerve cross-sectional area enlargement at the wrist (mean 16.3 mm 2 ), 100% had increased wrist-to-forearm median nerve area ratio (mean 2.4), 82.4% had decreased median nerve echogenicity, 75.0% had decreased median nerve mobility, and 7.1% had increased median nerve vascularity. A large proportion of patients with clinical CTS but normal NCS have abnormal neuromuscular ultrasound findings. Muscle Nerve 55: 913-915, 2017. © 2016 Wiley Periodicals, Inc.

[Radiation-induced genomic instability: phenomenon, molecular mechanisms, pathogenetic significance].

PubMed

Mazurik, V K; Mikhaĭlov, V F

2001-01-01

The recent data on the radiation-induced genome instability as a special state of progeny of cells irradiated in vitro as well as after a whole body exposure to ionizing radiation, that make these cells considerably different from normal, unirradiated cells, were considered. This state presents a number of cytogenetical, molecular-biological, cytological and biochemical manifestations untypical for normal cells. The state is controlled by the mechanisms of regulation of checkpoints of cell cycle, and apoptosis, that is under gene p53 control. The proof has been found that this state transfers from irradiated maternal cells to their surviving progeny by the epigenetical mechanisms and would exist until the cells restore the original state of response on the DNA damage. From the point of view of the genome instability conception, that considers the chromatine rearrangement as the adaptive-evolution mechanism of adaptation of the species to changeable environmental conditions, the radiation-induced genome instability may be considered as transition of irradiated progeny to the state of read these to adaptation changes with two alternative pathways. The first leads to adaptation to enviromental conditions and restoring of normal cell functions. The second presents the cell transition into the transformed state with remain genome instability and with increase of tumour growth probability.

THE CONTRIBUTIONS OF NORMAL AND ANOMALOUS OSMOSIS TO THE OSMOTIC EFFECTS ARISING ACROSS CHARGED MEMBRANES WITH SOLUTIONS OF ELECTROLYTES

PubMed Central

Grim, Eugene; Sollner, Karl

1957-01-01

The osmotic effect arising across a porous membrane separating the solution of an electrolyte from water (or a more dilute solution) is ordinarily due to both normal osmosis, as it occurs also with non-electrolytes, and to "anomalous" osmosis. It is shown that the normal osmotic component cannot be measured quantitatively by the conventional comparison with a non-electrolytic reference solute. Anomalous osmosis does not occur with electroneutral membranes. Accordingly, with membranes which can be charged and discharged reversibly (without changes in geometrical structure), such as many proteinized membranes, the osmotic effects caused by an electrolyte can be measured both when only normal osmosis arises (with the membrane in the electroneutral state) and when normal as well as anomalous osmosis occurs (with the membrane in a charged state). The difference between these two effects is the true anomalous osmosis. Data are presented on the osmotic effects across an oxyhemoglobin membrane in the uncharged state at pH 6.75 and in two charged states, positive at pH 4.0 and negative at pH 10.0, with solutions of a variety of electrolytes using a concentration ratio of 2:1 over a wide range of concentrations. The rates of the movement of liquid across the membrane against an inconsequentially small hydrostatic head are recorded instead of, as conventional, the physiologically less significant pressure rises after a standard time. PMID:13439166

Method for producing strain tolerant multifilamentary oxide superconducting wire

DOEpatents

Finnemore, D.K.; Miller, T.A.; Ostenson, J.E.; Schwartzkopf, L.A.; Sanders, S.C.

1994-07-19

A strain tolerant multifilamentary wire capable of carrying superconducting currents is provided comprising a plurality of discontinuous filaments formed from a high temperature superconducting material. The discontinuous filaments have a length at least several orders of magnitude greater than the filament diameter and are sufficiently strong while in an amorphous state to withstand compaction. A normal metal is interposed between and binds the discontinuous filaments to form a normal metal matrix capable of withstanding heat treatment for converting the filaments to a superconducting state. The geometry of the filaments within the normal metal matrix provides substantial filament-to-filament overlap, and the normal metal is sufficiently thin to allow supercurrent transfer between the overlapped discontinuous filaments but is also sufficiently thick to provide strain relief to the filaments. 6 figs.

Method for producing strain tolerant multifilamentary oxide superconducting wire

DOEpatents

Finnemore, Douglas K.; Miller, Theodore A.; Ostenson, Jerome E.; Schwartzkopf, Louis A.; Sanders, Steven C.

1994-07-19

A strain tolerant multifilamentary wire capable of carrying superconducting currents is provided comprising a plurality of discontinuous filaments formed from a high temperature superconducting material. The discontinuous filaments have a length at least several orders of magnitude greater than the filament diameter and are sufficiently strong while in an amorphous state to withstand compaction. A normal metal is interposed between and binds the discontinuous filaments to form a normal metal matrix capable of withstanding heat treatment for converting the filaments to a superconducting state. The geometry of the filaments within the normal metal matrix provides substantial filament-to-filament overlap, and the normal metal is sufficiently thin to allow supercurrent transfer between the overlapped discontinuous filaments but is also sufficiently thick to provide strain relief to the filaments.

Umklapp scattering as the origin of T -linear resistivity in the normal state of high- T c cuprate superconductors

DOE PAGES

Rice, T. Maurice; Robinson, Neil J.; Tsvelik, Alexei M.

2017-12-11

Here, the high-temperature normal state of the unconventional cuprate superconductors has resistivity linear in temperature T, which persists to values well beyond the Mott-Ioffe-Regel upper bound. At low temperatures, within the pseudogap phase, the resistivity is instead quadratic in T, as would be expected from Fermi liquid theory. Developing an understanding of these normal phases of the cuprates is crucial to explain the unconventional superconductivity. We present a simple explanation for this behavior, in terms of the umklapp scattering of electrons. This fits within the general picture emerging from functional renormalization group calculations that spurred the Yang-Rice-Zhang ansatz: Umklapp scatteringmore » is at the heart of the behavior in the normal phase.« less

Study of the Correlations and the MAXI Hardness Ratio between the Anomalous and Normal Low States of LMC X-3

NASA Astrophysics Data System (ADS)

Torpin, Trevor; Boyd, Patricia T.; Smale, Alan P.

2015-01-01

The bright, unusual black-hole X-ray binary LMC X-3 has been monitored virtually continuously by the Japanese MAXI X-ray All-Sky Monitor aboard the International Space Station (Matsuoka, et al., PASJ, 2009) from August 2009 to the present. Comparison with RXTE PCA and ASM light curves during the ~2.33-year period of overlap demonstrate that despite slight differences in energy-band boundaries both the ASM and MAXI faithfully reproduce characteristics of the high-amplitude, nonperiodic long-term variability, on the order of 100-300 days, clearly seen in the more sensitive PCA monitoring. The mechanism for this variability at a timescale many times longer than the 1.7-day orbital period is still unknown. Models to explain the long-term variability invoke mechanisms such as changes in mass transfer rate, and/or a precessing warped accretion disk. Observations of LMC X-3 have not definitely determined whether wind accretion or Roche-love overflow is the driver of the long-term variability. Recent MAXI monitoring of LMC X-3 includes excellent coverage of a rare anomalous low state (ALS) where the X-ray source cannot be distinguished from the background, as well as several normal low states, in which the source count rate passes smoothly through a low, yet detectable value. Pointed Swift XRT and UVOT observations also sample this ALS and one normal low state well. We combine these data sets to study the correlations between the wavelength regimes observed during the ALS versus the normal low. We also examine the behavior of the X-ray hardness ratios using XRT and MAXI monitoring data during the ALS versus the normal low state.

Single-molecule junction of an overcrowded ethylene with binary conductance states

NASA Astrophysics Data System (ADS)

Koike, Masato; Fujii, Shintaro; Cho, Haruna; Shoji, Yoshiaki; Nishino, Tomoaki; Fukushima, Takanori; Kiguchi, Manabu

2018-03-01

Overcrowded ethylene 1 shows mechanochromic behavior with contrasting color change between yellow and violet arising from its conformational isomerization, which should also be accompanied by the change in the electronic structure. Here, we report a single-molecule electronic study of 1 using scanning tunneling microcopy (STM) and STM-based break junction techniques. The single-molecule junction of 1 sandwiched by Au electrodes showed two distinct high- and low-conductance states with the conductance values of 0.003 and 0.0002 G 0. The high-conductance state is one order of magnitude more conductive than the low-conductance state. The two states can be ascribed to two conformational isomers of 1 in the junction.

A novel method for measuring hydraulic conductivity at the human blood-nerve barrier in vitro.

PubMed

Helton, E Scott; Palladino, Steven; Ubogu, Eroboghene E

2017-01-01

Microvascular barrier permeability to water is an essential biophysical property required for the homeostatic maintenance of unique tissue microenvironments. This is of particular importance in peripheral nerves where strict control of ionic concentrations is needed for axonal signal transduction. Previous studies have associated inflammation, trauma, toxin exposure and metabolic disease with increases in water influx and hydrostatic pressure in peripheral nerves with resultant endoneurial edema that may impair axonal function. The regulation of water permeability across endoneurial microvessels that form the blood-nerve barrier (BNB) is poorly understood. Variations exist in apparatus and methods used to measure hydraulic conductivity. The objective of the study was to develop a simplified hydraulic conductivity system using commercially available components to evaluate the BNB. We determined the mean hydraulic conductivity of cultured confluent primary and immortalized human endoneurial endothelial cell layers as 2.00×10 -7 and 2.17×10 -7 cm/s/cm H₂O respectively, consistent with restrictive microvascular endothelial cells in vitro. We also determined the mean hydraulic conductivity of immortalized human brain microvascular endothelial cell layers, a commonly used blood-brain barrier (BBB) cell line, as 0.20×10 -7 cm/s/cm H₂O, implying a mean 10-fold higher resistance to transendothelial water flux in the brain compared to peripheral nerves. To our knowledge, this is the first reported measurement of human BNB and BBB hydraulic conductivities. This model represents an important tool to further characterize the human BNB and deduce the molecular determinants and signaling mechanisms responsible for BNB hydraulic conductivity in normal and disease states in vitro. Copyright © 2016 Elsevier Inc. All rights reserved.

Thin semi-rigid coaxial cables for cryogenics applications

NASA Astrophysics Data System (ADS)

Kushino, Akihiro; Kasai, Soichi

2013-03-01

We have developed cryogenic coaxial cables for low temperature signal readout from sensitive devices, such as transition edge sensors, superconducting tunnel junctions, and kinetic inductance detectors. In order to reduce heat penetration into cryogenic stages, low thermal conductivity metals were chosen for both center and outer electrical conductors. Various types of coaxial cables, employing stainless-steel, cupro-nickel, brass, beryllium-copper, phosphor-bronze, niobium, and niobium-titanium, were manufactured using drawing dies. Thermal and electrical properties were investigated between 1 and 8 K. Coaxial cables made of copper alloys showed thermal conductance roughly consistent with literature, meanwhile Nb coaxial cable must be affected by the drawing process and thermal conductance was lowered. Attenuation of superconducting Nb and NbTi coaxial cables were observed to be adequately small up to above 10 GHz compared to those of normal conducting coaxial cables, which are subject to the Wiedemann-Franz law. We also measured normal conducting coaxial cables with silver-plated center conductors to improve high frequency performance.

Normal modes of weak colloidal gels

NASA Astrophysics Data System (ADS)

Varga, Zsigmond; Swan, James W.

2018-01-01

The normal modes and relaxation rates of weak colloidal gels are investigated in calculations using different models of the hydrodynamic interactions between suspended particles. The relaxation spectrum is computed for freely draining, Rotne-Prager-Yamakawa, and accelerated Stokesian dynamics approximations of the hydrodynamic mobility in a normal mode analysis of a harmonic network representing several colloidal gels. We find that the density of states and spatial structure of the normal modes are fundamentally altered by long-ranged hydrodynamic coupling among the particles. Short-ranged coupling due to hydrodynamic lubrication affects only the relaxation rates of short-wavelength modes. Hydrodynamic models accounting for long-ranged coupling exhibit a microscopic relaxation rate for each normal mode, λ that scales as l-2, where l is the spatial correlation length of the normal mode. For the freely draining approximation, which neglects long-ranged coupling, the microscopic relaxation rate scales as l-γ, where γ varies between three and two with increasing particle volume fraction. A simple phenomenological model of the internal elastic response to normal mode fluctuations is developed, which shows that long-ranged hydrodynamic interactions play a central role in the viscoelasticity of the gel network. Dynamic simulations of hard spheres that gel in response to short-ranged depletion attractions are used to test the applicability of the density of states predictions. For particle concentrations up to 30% by volume, the power law decay of the relaxation modulus in simulations accounting for long-ranged hydrodynamic interactions agrees with predictions generated by the density of states of the corresponding harmonic networks as well as experimental measurements. For higher volume fractions, excluded volume interactions dominate the stress response, and the prediction from the harmonic network density of states fails. Analogous to the Zimm model in polymer physics, our results indicate that long-ranged hydrodynamic interactions play a crucial role in determining the microscopic dynamics and macroscopic properties of weak colloidal gels.

Tidal friction and generalized Cassini's laws in the solar system. [for planetary spin axis rotation

NASA Technical Reports Server (NTRS)

Ward, W. R.

1975-01-01

The tidal drift toward a generalized Cassini state of rotation of the spin axis of a planet or satellite in a precessing orbit is described. Generalized Cassini's laws are applied to several solar system objects and the location of their spin axes estimated. Of those considered only the moon definitely occupies state 2 with the spin axis near to the normal of the invariable plane. Most objects appear to occupy state 1 with the spin axis near to the orbit normal. Iapetus could occupy either state depending on its oblateness. In addition, the resonant rotation of Mercury is found to have little effect on the tidal drift of its spin axis toward state 1.

Normalization regulates competition for visual awareness

PubMed Central

Ling, Sam; Blake, Randolph

2012-01-01

Summary Signals in our brain are in a constant state of competition, including those that vie for motor control, sensory dominance and awareness. To shed light on the mechanisms underlying neural competition, we exploit binocular rivalry, a phenomenon that allows us to probe the competitive process that ordinarily transpires outside of our awareness. By measuring psychometric functions under different states of rivalry, we discovered a pattern of gain changes that are consistent with a model of competition in which attention interacts with normalization processes, thereby driving the ebb and flow between states of awareness. Moreover, we reveal that attention plays a crucial role in modulating competition; without attention, rivalry suppression for high-contrast stimuli is negligible. We propose a framework whereby our visual awareness of competing sensory representations is governed by a common neural computation: normalization. PMID:22884335

Pressure effect on the superconducting and the normal state of β -B i2Pd

NASA Astrophysics Data System (ADS)

Pristáš, G.; Orendáč, Mat.; Gabáni, S.; Kačmarčík, J.; Gažo, E.; Pribulová, Z.; Correa-Orellana, A.; Herrera, E.; Suderow, H.; Samuely, P.

2018-04-01

The pressure effect up to 24.0 kbar on superconducting and normal-state properties of β -B i2Pd single crystal (Tc≈4.98 K at ambient pressure) has been investigated by measurements of the electrical resistivity. In addition, we have performed the heat capacity measurements in the temperature range 0.7-300 K at ambient pressure. The recent calculations of electronic density of states, electron-phonon interaction spectral function, and phonon density of states of β -B i2Pd [Zheng and Margine, Phys. Rev. B 95, 014512 (2017), 10.1103/PhysRevB.95.014512], are used to fit the resistivity and the heat capacity data. In the superconducting state we have focused on the influence of pressure on the superconducting transition temperature Tc and upper critical field Hc 2 and a negative effect with d Tc/d p =-0.025 K /kbar and d Hc 2/d p =-8 mT /kbar is found. A simplified Bloch-Grüneisen model was used to analyze the pressure effect on the temperature dependence of the normal-state resistivity. The obtained results point to a decrease of the electron-phonon coupling parameter λ and to a shift of phonon frequencies to higher values with pressure. Moreover, the temperature dependence of the normal-state resistivity follows a T2 dependence above Tc up to about 25 K. Together with the enhanced value of Sommerfeld coefficient γ =13.23 mJ mo l-1K-2 these results point to a certain role of the electron-electron interaction in the superconducting pairing mechanism in β -B i2Pd .

Diagnostic transitions in mild cognitive impairment subtypes.

PubMed

Forlenza, Orestes Vicente; Diniz, Breno Satler; Nunes, Paula Villela; Memória, Claudia Maia; Yassuda, Monica Sanches; Gattaz, Wagner Farid

2009-12-01

At least for a subset of patients, the clinical diagnosis of mild cognitive impairment (MCI) may represent an intermediate stage between normal aging and dementia. Nevertheless, the patterns of transition of cognitive states between normal cognitive aging and MCI to dementia are not well established. In this study we address the pattern of transitions between cognitive states in patients with MCI and healthy controls, prior to the conversion to dementia. 139 subjects (78% women, mean age, 68.5 +/- 6.1 years; mean educational level, 11.7 +/- 5.4 years) were consecutively assessed in a memory clinic with a standardized clinical and neuropsychological protocol, and classified as cognitively healthy (normal controls) or with MCI (including subtypes) at baseline. These subjects underwent annual reassessments (mean duration of follow-up: 2.7 +/- 1.1 years), in which cognitive state was ascertained independently of prior diagnoses. The pattern of transitions of the cognitive state was determined by Markov chain analysis. The transitions from one cognitive state to another varied substantially between MCI subtypes. Single-domain MCI (amnestic and non-amnestic) more frequently returned to normal cognitive state upon follow-up (22.5% and 21%, respectively). Among subjects who progressed to Alzheimer's disease (AD), the most common diagnosis immediately prior conversion was multiple-domain MCI (85%). The clinical diagnosis of MCI and its subtypes yields groups of patients with heterogeneous patterns of transitions between one given cognitive state to another. The presence of more severe and widespread cognitive deficits, as indicated by the group of multiple-domain amnestic MCI may be a better predictor of AD than single-domain amnestic or non-amnestic deficits. These higher-risk individuals could probably be the best candidates for the development of preventive strategies and early treatment for the disease.

Spin Transport in Electric-Barrier-Modulated Ferromagnetic/Normal/Ferromagnetic Monolayer Zigzag MoS2 Nanoribbon Junction

NASA Astrophysics Data System (ADS)

Xia, Y.-Y.; Yuan, R.-Y.; Yang, Q.-J.; Sun, Q.; Zheng, J.; Guo, Y.

In this paper, with the three-band tight-binding model and non-equilibrium Green’s function technique, we investigate spin transport in electric-barrier-modulated Ferromagnetic/Normal/Ferromagnetic (F/N/F) monolayer (ML) zigzag MoS2 nanoribbon junction. The results demonstrate that once the double electric barriers structure emerges, the oscillations of spin conductances become violent, especially for spin-down conductance, the numbers of resonant peaks increase obviously, thus we can obtain 100% spin polarization in the low energy region. It is also found that with the intensity of the exchange field enhancement, the resonant peaks of spin-up and spin-down conductances move in the opposite direction in a certain energy region. As a consequence, the spin-down conductance can be filtered out completely. The findings here indicate that the present structure may be considered as a good candidate for spin filter.

Diagnostic value of the near-nerve needle sensory nerve conduction in sensory inflammatory demyelinating polyneuropathy.

PubMed

Odabasi, Zeki; Oh, Shin J

2018-03-01

In this study we report the diagnostic value of the near-nerve needle sensory nerve conduction study (NNN-SNCS) in sensory inflammatory demyelinating polyneuropathy (IDP) in which the routine nerve conduction study was normal or non-diagnostic. The NNN-SNCS was performed to identify demyelination in the plantar nerves in 14 patients and in the median or ulnar nerve in 2 patients with sensory IDP. In 16 patients with sensory IDP, routine NCSs were either normal or non-diagnostic for demyelination. Demyelination was identified by NNN-SNCS by dispersion and/or slow nerve conduction velocity (NCV) below the demyelination marker. Immunotherapy was initiated in 11 patients, 10 of whom improved or remained stable. NNN-SNCS played an essential role in identifying demyelinaton in 16 patients with sensory IDP, leading to proper treatment. Muscle Nerve 57: 414-418, 2018. © 2017 Wiley Periodicals, Inc.

Effect of d-wave pairing symmetry in transport properties of silicene-based superconductor junction

NASA Astrophysics Data System (ADS)

Vosoughi-nia, S.; Rashedi, G.; hajati, Y.

2018-06-01

We theoretically study the tunneling conductance of a normal/d-wave superconductor silicene junction using Blonder-Tinkham-Klapwijk (BTK) formalism. We discuss how the conductance spectra are affected by changing the chemical potential (μN) in the normal silicene region. It is obtained that the amplitude of the spin/valley-dependent Andreev reflection (AR) and charge conductance (G) of the junction can be strongly modulated by the orientation angle of superconductive gap (β) and perpendicular electric field (Ez). We demonstrate that the charge conductance exhibits an oscillatory behavior as a function of β by a period of π/2. Remarkably, variation of μN strongly modifies the amplitude of the oscillations and periodically there are transport gaps in the G - β oscillations for a range of μN. These findings suggest that one may experimentally tune the transport properties of the junction through changing β, Ez and μN.

31 CFR 560.507 - Accompanied baggage authorized.

Code of Federal Regulations, 2011 CFR

2011-07-01

... the United States directly or indirectly from Iran are authorized to import into the United States... Iran are authorized to export from the United States accompanied baggage normally incident to travel...

31 CFR 560.507 - Accompanied baggage authorized.

Code of Federal Regulations, 2010 CFR

2010-07-01

... the United States directly or indirectly from Iran are authorized to import into the United States... Iran are authorized to export from the United States accompanied baggage normally incident to travel...

A review of inherent safety characteristics of metal alloy sodium-cooled fast reactor fuel against postulated accidents

DOE PAGES

Sofu, Tanju

2015-04-01

The thermal, mechanical, and neutronic performance of the metal alloy fast reactor fuel design complements the safety advantages of the liquid metal cooling and the pool-type primary system. Together, these features provide large safety margins in both normal operating modes and for a wide range of postulated accidents. In particular, they maximize the measures of safety associated with inherent reactor response to unprotected, double-fault accidents, and to minimize risk to the public and plant investment. High thermal conductivity and high gap conductance play the most significant role in safety advantages of the metallic fuel, resulting in a flatter radial temperaturemore » profile within the pin and much lower normal operation and transient temperatures in comparison to oxide fuel. Despite the big difference in melting point, both oxide and metal fuels have a relatively similar margin to melting during postulated accidents. When the metal fuel cladding fails, it typically occurs below the coolant boiling point and the damaged fuel pins remain coolable. Metal fuel is compatible with sodium coolant, eliminating the potential of energetic fuel--coolant reactions and flow blockages. All these, and the low retained heat leading to a longer grace period for operator action, are significant contributing factors to the inherently benign response of metallic fuel to postulated accidents. This paper summarizes the past analytical and experimental results obtained in past sodium-cooled fast reactor safety programs in the United States, and presents an overview of fuel safety performance as observed in laboratory and in-pile tests.« less

Regional transport, source apportionment and health impact of PM10 bound polycyclic aromatic hydrocarbons in Singapore's atmosphere.

PubMed

Urbančok, Dejan; Payne, Anthony J R; Webster, Richard D

2017-10-01

A study of 16 United States Environmental Protection Agency (USEPA) priority listed PAHs associated with particulate matter ≤ 10 μm (PM 10 ) was conducted in Singapore during the period 29th May 2015 to 28th May 2016. The sampling period coincided with an extensive, regional smoke haze episode (5th September to 25th October) that occurred as a result of forest and peat fires in neighboring Indonesia. Throughout this study, 54 atmospheric PM 10 samples were collected in 24 h periods using a high volume sampler (HVS) and quarts fiber filters (QFF) as the collection medium. Hysplit software for computing 3-D backward air mass trajectories, diagnostic ratio analysis and ring number distribution calculations were used to examine the sources of PAHs in the atmosphere in Singapore. Under normal conditions the total PAH concentrations were in a range from 0.68 ng m -3 to 3.07 ng m -3 , while for the high haze period the results showed approximately double the concentrations with a maximum value of 5.97 ng m -3 . Diagnostic ratio (DR) and principal component analysis (PCA) were conducted and indicated the contribution of the traffic as a dominant pyrogenic source of PAHs during normal periods, while results from the haze dataset showed relatively strong influence of smoke from peat and forest fires in Indonesia. Environmental and health risk from PAHs were assessed for both regular and hazy days. Copyright © 2017 Elsevier Ltd. All rights reserved.

A review of inherent safety characteristics of metal alloy sodium-cooled fast reactor fuel against postulated accidents

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

Sofu, Tanju

2015-04-01

The thermal, mechanical, and neutronic performance of the metal alloy fast reactor fuel design complements the safety advantages of the liquid metal cooling and the pool-type primary system. Together, these features provide large safety margins in both normal operating modes and for a wide range of postulated accidents. In particular, they maximize the measures of safety associated with inherent reactor response to unprotected, double-fault accidents, and to minimize risk to the public and plant investment. High thermal conductivity and high gap conductance play the most significant role in safety advantages of the metallic fuel, resulting in a flatter radial temperaturemore » profile within the pin and much lower normal operation and transient temperatures in comparison to oxide fuel. Despite the big difference in melting point, both oxide and metal fuels have a relatively similar margin to melting during postulated accidents. When the metal fuel cladding fails, it typically occurs below the coolant boiling point and the damaged fuel pins remain cool-able. Metal fuel is compatible with sodium coolant, eliminating the potential of energetic fuel coolant reactions and flow blockages. All these, and the low retained heat leading to a longer grace period for operator action, are significant contributing factors to the inherently benign response of metallic fuel to postulated accidents. This paper summarizes the past analytical and experimental results obtained in past sodium-cooled fast reactor safety programs in the United States, and presents an overview of fuel safety performance as observed in laboratory and in-pile tests.« less

Maximum on the Electrical Conductivity Polytherm of Molten TeCl4

NASA Astrophysics Data System (ADS)

Salyulev, Alexander B.; Potapov, Alexei M.

2017-05-01

The electrical conductivity of molten TeCl4 was measured up to 761K, i.e. 106 degrees above the normal boiling point of the salt. For the first time it was found that TeCl4 electrical conductivity polytherm has a maximum. It was recorded at 705K (κmax=0.245 Sm/cm), whereupon the conductivity decreases as the temperature rises. The activation energy of electrical conductivity was calculated.

Anomalous proximity effect in an inhomogeneous disordered superconductor.

PubMed

Escoffier, W; Chapelier, C; Hadacek, N; Villégier, J-C

2004-11-19

By combining very low temperature scanning tunneling microscopy and spectroscopy on a TiN film we have observed a nonuniform state comprising of superconducting (S) and normal (N) areas. The local density of states displays a spatial dependence between S and N different from the usual proximity effect. We conclude that mesoscopic fluctuations might play a major role in accordance with recent theories describing superconductor-normal-metal quantum transition.

Advanced Very High Resolution Radiometer Normalized Difference Vegetation Index Composites

USGS Publications Warehouse

,

2005-01-01

The Advanced Very High Resolution Radiometer (AVHRR) is a broad-band scanner with four to six bands, depending on the model. The AVHRR senses in the visible, near-, middle-, and thermal- infrared portions of the electromagnetic spectrum. This sensor is carried on a series of National Oceanic and Atmospheric Administration (NOAA) Polar Orbiting Environmental Satellites (POES), beginning with the Television InfraRed Observation Satellite (TIROS-N) in 1978. Since 1989, the United States Geological Survey (USGS) Center for Earth Resources Observation and Science (EROS) has been mapping the vegetation condition of the United States and Alaska using satellite information from the AVHRR sensor. The vegetation condition composites, more commonly called greenness maps, are produced every week using the latest information on the growth and condition of the vegetation. One of the most important aspects of USGS greenness mapping is the historical archive of information dating back to 1989. This historical stretch of information has allowed the USGS to determine a 'normal' vegetation condition. As a result, it is possible to compare the current week's vegetation condition with normal vegetation conditions. An above normal condition could indicate wetter or warmer than normal conditions, while a below normal condition could indicate colder or dryer than normal conditions. The interpretation of departure from normal will depend on the season and geography of a region.

Normal state above the upper critical field in Fe 1 + y Te 1 - x ( Se , S ) x

DOE PAGES

Wang, Aifeng; Kampert, Erik; Saadaoui, H.; ...

2017-05-03

Here, we have investigated the magnetotransport above the upper critical field ( H c 2 ) in Fe 1.14 Te 0.7 Se 0.3 , Fe 1.02 Te 0.61 Se 0.39 , Fe 1.05 Te 0.89 Se 0.11 , and Fe 1.06 Te 0.86 S 0.14 . The μ SR measurements confirm electronic phase separation in Fe 1.06 Te 0.86 S 0.14 , similar to Fe 1 + y Te 1 - x Se x . We found that superconductivity is suppressed in high magnetic fields above 60 T, allowing us to gain insight into the normal-state properties below the zero-fieldmore » superconducting transition temperature ( T c ). We also show that the resistivity of Fe 1.14 Te 0.7 Se 0.3 and Fe 1.02 Te 0.61 Se 0.39 above H c 2 is metallic as T → 0 , just like the normal-state resistivity above T c . On the other hand, the normal-state resistivity in Fe 1.05 Te 0.89 Se 0.11 and Fe 1.06 Te 0.86 S 0.14 is nonmetallic down to lowest temperatures, reflecting the superconductor-insulator transition due to electronic phase separation.« less

Effects of wear on structure-sensitive magnetic properties of ceramic ferrite in contact with magnetic tape

NASA Technical Reports Server (NTRS)

Miyoshi, K.; Buckley, D. H.; Tanaka, K.

1985-01-01

Wear experiments and electron microscopy and diffraction studies were conducted to examine the wear and deformed layers in single-crystal Mn-Zn (ceramic) ferrite magnetic head material in contact with magnetic tape and the effects of that contact on magnetic properties. The crystalline state of the single-crystal magnetic head was changed drastically during the sliding process. A nearly amorphous structure was produced on its wear surface. Deformation in the surficial layer of the magnetic head was a critical factor in readback signal loss above 2.5 dB. The signal output level was reduced as applied normal load was increased. Considerable plastic flow occurred on the magnetic tape surface with sliding, and the signal loss due to the tape wear was approximately 1 dB.

Electrically switchable polymer liquid crystal and polymer birefringent flake in fluid host systems and optical devices utilizing same

DOEpatents

Marshall, Kenneth L.; Kosc, Tanya Z.; Jacobs, Stephen D.; Faris, Sadeg M.; Li, Le

2003-12-16

Flakes or platelets of polymer liquid crystals (PLC) or other birefringent polymers (BP) suspended in a fluid host medium constitute a system that can function as the active element in an electrically switchable optical device when the suspension is either contained between a pair of rigid substrates bearing transparent conductive coatings or dispersed as microcapsules within the body of a flexible host polymer. Optical properties of these flake materials include large effective optical path length, different polarization states and high angular sensitivity in their selective reflection or birefringence. The flakes or platelets of these devices need only a 3-20.degree. rotation about the normal to the cell surface to achieve switching characteristics obtainable with prior devices using particle rotation or translation.

Transport properties of field-effect transistor with Langmuir-Blodgett films of C60 dendrimer and estimation of impurity levels

NASA Astrophysics Data System (ADS)

Kawasaki, Naoko; Nagano, Takayuki; Kubozono, Yoshihiro; Sako, Yuuki; Morimoto, Yu; Takaguchi, Yutaka; Fujiwara, Akihiko; Chu, Chih-Chien; Imae, Toyoko

2007-12-01

Field-effect transistor (FET) device has been fabricated with Langmuir-Blodgett films of C60 dendrimer. The device showed n-channel normally off characteristics with the field-effect mobility of 2.7×10-3cm2V-1s-1 at 300K, whose value is twice as high as that (1.4×10-3cm2V-1s-1) for the FET with spin-coated films of C60 dendrimer. This originates from the formation of ordered π-conduction network of C60 moieties. From the temperature dependence of field-effect mobility, a structural phase transition has been observed at around 300K. Furthermore, the density of states for impurity levels was estimated in the Langmuir-Blodgett films.

Broken symmetry and critical transport properties of random metals

PubMed Central

Phillips, J. C.

1997-01-01

Recent experimental data on the conductivity σ+(T), T → 0, on the metallic side of the metal–insulator transition in ideally random (neutron transmutation-doped) 70Ge:Ga have shown that σ+(0) ∝ (N − Nc)μ with μ = ½, confirming earlier ultra-low-temperature results for Si:P. This value is inconsistent with theoretical predictions based on diffusive classical scaling models, but it can be understood by a quantum-directed percolative filamentary amplitude model in which electronic basis states exist which have a well-defined momentum parallel but not normal to the applied electric field. The model, which is based on a new kind of broken symmetry, also explains the anomalous sign reversal of the derivative of the temperature dependence in the critical regime. PMID:11038579