f(R) gravity and chameleon theories

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

Brax, Philippe; Bruck, Carsten van de; Davis, Anne-Christine

2008-11-15

We analyze f(R) modifications of Einstein's gravity as dark energy models in the light of their connection with chameleon theories. Formulated as scalar-tensor theories, the f(R) theories imply the existence of a strong coupling of the scalar field to matter. This would violate all experimental gravitational tests on deviations from Newton's law. Fortunately, the existence of a matter dependent mass and a thin-shell effect allows one to alleviate these constraints. The thin-shell condition also implies strong restrictions on the cosmological dynamics of the f(R) theories. As a consequence, we find that the equation of state of dark energy is constrainedmore » to be extremely close to -1 in the recent past. We also examine the potential effects of f(R) theories in the context of the Eoet-wash experiments. We show that the requirement of a thin shell for the test bodies is not enough to guarantee a null result on deviations from Newton's law. As long as dark energy accounts for a sizeable fraction of the total energy density of the Universe, the constraints that we deduce also forbid any measurable deviation of the dark energy equation of state from -1. All in all, we find that both cosmological and laboratory tests imply that f(R) models are almost coincident with a {lambda}CDM model at the background level.« less

Influence of Convective Effect of Solar Winds on the CME Transit Time

NASA Astrophysics Data System (ADS)

Sun, Lu-yuan

2017-10-01

Based on an empirical model for predicting the transit time of coronal mass ejections (CMEs) proposed by Gopalswamy, 52 CME events which are related to the geomagnetic storms of Dst < -50 nT, and 10 CME events which caused extremely strong geomagnetic storms (Dst < -200 nT) in 1996- 2007 are selected, and combined with the observational data of the interplanetary solar winds that collected by the ACE satellite at 1AU, to analyze the influence of convective effect of ambient solar winds on the prediction of the CME transit time when it arrives at a place of 1 AU. After taking the convective effect of ambient solar winds into account, the standard deviation of predictions is reduced from 16.5 to 11.4 hours for the 52 CME events, and the prediction error is less than 15 hours for 68% of these events; while the standard deviation of predictions is reduced from 10.6 to 6.5 hours for the 10 CME events that caused extremely strong geomagnetic storms, and the prediction error is less than 5 hours for 6 of the 10 events. These results show that taking the convective effect of ambient solar winds into account can reduce the standard deviation of the predicted CME transit time, hence the convective effect of solar winds plays an important role for predicting the transit times of CME events.

Multipole moments of bumpy black holes

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

Vigeland, Sarah J.

General relativity predicts the existence of black holes, compact objects whose spacetimes depend only on their mass, spin, and charge in vacuum (the 'no-hair' theorem). As various observations probe deeper into the strong fields of black hole candidates, it is becoming possible to test this prediction. Previous work suggested that such tests can be performed by measuring whether the multipolar structure of black hole candidates has the form that general relativity demands, and introduced a family of 'bumpy black hole' spacetimes to be used for making these measurements. These spacetimes have generalized multipoles, where the deviation from the Kerr metricmore » depends on the spacetime's 'bumpiness'. In this paper, we show how to compute the Geroch-Hansen moments of a bumpy black hole, demonstrating that there is a clean mapping between the deviations used in the bumpy black hole formalism and the Geroch-Hansen moments. We also extend our previous results to define bumpy black holes whose current moments, analogous to magnetic moments of electrodynamics, deviate from the canonical Kerr value.« less

Ionospheric reflection of the magnetic activity described by the index η

NASA Astrophysics Data System (ADS)

Dziak-Jankowska, Beata; Stanisławska, Iwona; Ernst, Tomasz; Tomasik, Łukasz

2011-09-01

Differences in the external part of the vertical geomagnetic component point to the existence of local inhomogeneities in the magnetosphere or the ionosphere. Usually used magnetic indices are not sufficient to express the state of ionosphere, the common used global Kp index derived in the three-hour interval does not indicate much more rapidly changes appearing in ionosphere. Magnetic index η reflects ionospheric disturbances when other indices show very quiet conditions. Data of ionospheric characteristics (foE, foEs, h'E, h'F2) during 28-day long quiet day conditions (Kp = 0-2) in 2004 were analyzed. The correlations between strong local disturbances in ionosphere during very quiet days and high values of magnetic index η were found. The most sensitive to magnetic influence - ionospheric E layer data (foE characteristic) - reaches median deviations up to (+0.8 MHz and -0.8 MHz) during very low magnetic activity (Kp = 0-1). The high peaks (2-2.7) of the magnetic index η correlate in time with large local median deviations of foE. Such local deviations can suggest local inhomogeneities (vertical drifts) in the ionosphere. The correlation in space is not trivial. The strong peak of η is situated between the positive and negative deviations of foE. Additional observation is connected with correlation in time of the high η value with the negative median deviations of h'F2 (in some cases up to -90 km). The analysis was based on one-minute data recorded at each of 20 European Magnetic Observatories working in the INTERMAGNET network and from 19 ionosondes for 2004. Ionospheric data are sparse in time and in space in opposite to the magnetic data. The map of the magnetic indices can suggest the behavior of ionospheric characteristics in the areas where we have no data.

Last Millennium ENSO-Mean State Interactions in the Tropical Pacific

NASA Astrophysics Data System (ADS)

Wyman, D. A.; Conroy, J. L.; Karamperidou, C.

2017-12-01

The nature and degree of interaction between the mean state of the tropical Pacific and ENSO remains an open question. Here we use high temporal resolution, tropical Pacific sea surface temperature (SST) records from the last millennium to investigate the relationship between ENSO and the tropical Pacific zonal sea surface temperature gradient (hereafter dSST). A dSST time series was created by standardizing, interpolating, and compositing 7 SST records from the western and 3 SST records from the eastern tropical Pacific. Propagating the age uncertainty of each of these records was accomplished through a Monte Carlo Empirical Orthogonal Function analysis. We find last millennium dSST is strong from 700 to 1300 CE, begins to weaken at approximately 1300 CE, and decreases more rapidly at 1700 CE. dSST was compared to 14 different ENSO reconstructions, independent of the records used to create dSST, to assess the nature of the ENSO-mean state relationship. dSST correlations with 50-year standard deviations of ENSO reconstructions are consistently negative, suggesting that more frequent, strong El Niño events on this timescale reduces dSST. To further assess the strength and direction of the ENSO-dSST relationship, moving 100-year standard deviations of ENSO reconstructions were compared to moving 100-year averages of dSST using Cohen's Kappa statistic, which measures categorical agreement. The Li et al. (2011) and Li et al. (2013) Nino 3.4 ENSO reconstructions had the highest agreement with dSST (k=0.80 and 0.70, respectively), with greater ENSO standard deviation coincident with periods of weak dSST. Other ENSO reconstructions showed weaker agreement with dSST, which may be partly due to low sample size. The consistent directional agreement of dSST with ENSO, coupled with the inability of strong ENSO events to develop under a weak SST gradient, suggests periods of more frequent strong El Niño events reduced tropical Pacific dSST on centennial timescales over the last millennium.

Correlation between Extraocular Muscle Size Measured by Computed Tomography and the Vertical Angle of Deviation in Thyroid Eye Disease

PubMed Central

Lee, Ju-Yeun; Bae, Kunho; Park, Kyung-Ah; Lyu, In Jeong; Oh, Sei Yeul

2016-01-01

The aim of this study was to investigate extraocular muscle (EOM) volume and cross-sectional area using computed tomography (CT), and to determine the relationship between EOM size and the vertical angle of deviation in thyroid eye disease (TED). Twenty-nine TED patients (58 orbits) with vertical strabismus were enrolled in the study. All patients underwent complete ophthalmic examination including prism, alternate cover, and Krimsky tests. Orbital CT scans were also performed on each patient. Digital image analysis was used to quantify superior rectus (SR) and inferior rectus (IR) muscle cross-sectional areas and volumes. Measurements were compared with those of controls. The correlation between muscle size and degree of vertical angle deviation was evaluated. The mean vertical angle of deviation was 26.2 ± 4.1 prism diopters. The TED group had a greater maximum cross-sectional area and EOM volume in the SR and IR than the control group (all p<0.001). Area and volume of the IR were correlated with the angle of deviation, but the SR alone did not show a significant correlation. The maximum cross-sectional area and volume of [Right IR + Left SR − Right SR − Left IR] was strongly correlated with the vertical angle of deviation (P<0.001). Quantitative CT of the orbit with evaluation of the area and volume of EOMs may be helpful in anticipating and monitoring vertical strabismus in TED patients. PMID:26820406

Correlation between Extraocular Muscle Size Measured by Computed Tomography and the Vertical Angle of Deviation in Thyroid Eye Disease.

PubMed

Lee, Ju-Yeun; Bae, Kunho; Park, Kyung-Ah; Lyu, In Jeong; Oh, Sei Yeul

2016-01-01

The aim of this study was to investigate extraocular muscle (EOM) volume and cross-sectional area using computed tomography (CT), and to determine the relationship between EOM size and the vertical angle of deviation in thyroid eye disease (TED). Twenty-nine TED patients (58 orbits) with vertical strabismus were enrolled in the study. All patients underwent complete ophthalmic examination including prism, alternate cover, and Krimsky tests. Orbital CT scans were also performed on each patient. Digital image analysis was used to quantify superior rectus (SR) and inferior rectus (IR) muscle cross-sectional areas and volumes. Measurements were compared with those of controls. The correlation between muscle size and degree of vertical angle deviation was evaluated. The mean vertical angle of deviation was 26.2 ± 4.1 prism diopters. The TED group had a greater maximum cross-sectional area and EOM volume in the SR and IR than the control group (all p<0.001). Area and volume of the IR were correlated with the angle of deviation, but the SR alone did not show a significant correlation. The maximum cross-sectional area and volume of [Right IR + Left SR - Right SR - Left IR] was strongly correlated with the vertical angle of deviation (P<0.001). Quantitative CT of the orbit with evaluation of the area and volume of EOMs may be helpful in anticipating and monitoring vertical strabismus in TED patients.

Structure-property relations of orthorhombic [(CH3)3NCH2COO]2(CuCl2)3 · 2H2 O

NASA Astrophysics Data System (ADS)

Haussühl, Eiken; Schreuer, Jürgen; Wiehl, Leonore; Paulsen, Natalia

2014-04-01

Large single crystals of orthorhombic [(CH3)3NCH2COO]2(CuCl2)3 · 2H2 O with dimensions up to 40×40×30 mm3 were grown from aqueous solutions. The elastic and piezoelastic coefficients were derived from ultrasonic resonance frequencies and their shifts upon variation of pressure, respectively, using the plate-resonance technique. Additionally, the coefficients of thermal expansion were determined between 95 K and 305 K by dilatometry. The elastic behaviour at ambient conditions is dominated by the 2-dimensional network of strong hydrogen bonds within the (001) plane leading to a corresponding pseudo-tetragonal anisotropy of the longitudinal elastic stiffness. The variation of elastic properties with pressure, however, as well as the thermal expansion shows strong deviations from the pseudo-tetragonal symmetry. These deviations are probably correlated with tilts of the elongated tri-nuclear betaine-CuCl2-water complexes. Neither the thermal expansion nor the specific heat capacity gives any hint on a phase transition in the investigated temperature range.

Describing temporal variation in reticuloruminal pH using continuous monitoring data.

PubMed

Denwood, M J; Kleen, J L; Jensen, D B; Jonsson, N N

2018-01-01

Reticuloruminal pH has been linked to subclinical disease in dairy cattle, leading to considerable interest in identifying pH observations below a given threshold. The relatively recent availability of continuously monitored data from pH boluses gives new opportunities for characterizing the normal patterns of pH over time and distinguishing these from abnormal patterns using more sensitive and specific methods than simple thresholds. We fitted a series of statistical models to continuously monitored data from 93 animals on 13 farms to characterize normal variation within and between animals. We used a subset of the data to relate deviations from the normal pattern to the productivity of 24 dairy cows from a single herd. Our findings show substantial variation in pH characteristics between animals, although animals within the same farm tended to show more consistent patterns. There was strong evidence for a predictable diurnal variation in all animals, and up to 70% of the observed variation in pH could be explained using a simple statistical model. For the 24 animals with available production information, there was also a strong association between productivity (as measured by both milk yield and dry matter intake) and deviations from the expected diurnal pattern of pH 2 d before the productivity observation. In contrast, there was no association between productivity and the occurrence of observations below a threshold pH. We conclude that statistical models can be used to account for a substantial proportion of the observed variability in pH and that future work with continuously monitored pH data should focus on deviations from a predictable pattern rather than the frequency of observations below an arbitrary pH threshold. Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Symmetry analysis of talus bone: A Geometric morphometric approach.

PubMed

Islam, K; Dobbe, A; Komeili, A; Duke, K; El-Rich, M; Dhillon, S; Adeeb, S; Jomha, N M

2014-01-01

The main object of this study was to use a geometric morphometric approach to quantify the left-right symmetry of talus bones. Analysis was carried out using CT scan images of 11 pairs of intact tali. Two important geometric parameters, volume and surface area, were quantified for left and right talus bones. The geometric shape variations between the right and left talus bones were also measured using deviation analysis. Furthermore, location of asymmetry in the geometric shapes were identified. Numerical results showed that talus bones are bilaterally symmetrical in nature, and the difference between the surface area of the left and right talus bones was less than 7.5%. Similarly, the difference in the volume of both bones was less than 7.5%. Results of the three-dimensional (3D) deviation analyses demonstrated the mean deviation between left and right talus bones were in the range of -0.74 mm to 0.62 mm. It was observed that in eight of 11 subjects, the deviation in symmetry occurred in regions that are clinically less important during talus surgery. We conclude that left and right talus bones of intact human ankle joints show a strong degree of symmetry. The results of this study may have significance with respect to talus surgery, and in investigating traumatic talus injury where the geometric shape of the contralateral talus can be used as control. Cite this article: Bone Joint Res 2014;3:139-45.

Efficiency of thin magnetically arrested discs around black holes

NASA Astrophysics Data System (ADS)

Avara, Mark J.; McKinney, Jonathan C.; Reynolds, Christopher S.

2016-10-01

The radiative and jet efficiencies of thin magnetized accretion discs around black holes (BHs) are affected by BH spin and the presence of a magnetic field that, when strong, could lead to large deviations from Novikov-Thorne (NT) thin disc theory. To seek the maximum deviations, we perform general relativistic magnetohydrodynamic simulations of radiatively efficient thin (half-height H to radius R of H/R ≈ 0.10) discs around moderately rotating BHs with a/M = 0.5. First, our simulations, each evolved for more than 70 000 rg/c (gravitational radius rg and speed of light c), show that large-scale magnetic field readily accretes inward even through our thin disc and builds-up to the magnetically arrested disc (MAD) state. Secondly, our simulations of thin MADs show the disc achieves a radiative efficiency of ηr ≈ 15 per cent (after estimating photon capture), which is about twice the NT value of ηr ˜ 8 per cent for a/M = 0.5 and gives the same luminosity as an NT disc with a/M ≈ 0.9. Compared to prior simulations with ≲10 per cent deviations, our result of an ≈80 per cent deviation sets a new benchmark. Building on prior work, we are now able to complete an important scaling law which suggests that observed jet quenching in the high-soft state in BH X-ray binaries is consistent with an ever-present MAD state with a weak yet sustained jet.

Symmetry analysis of talus bone

PubMed Central

Islam, K.; Dobbe, A.; Komeili, A.; Duke, K.; El-Rich, M.; Dhillon, S.; Adeeb, S.; Jomha, N. M.

2014-01-01

Objective The main object of this study was to use a geometric morphometric approach to quantify the left-right symmetry of talus bones. Methods Analysis was carried out using CT scan images of 11 pairs of intact tali. Two important geometric parameters, volume and surface area, were quantified for left and right talus bones. The geometric shape variations between the right and left talus bones were also measured using deviation analysis. Furthermore, location of asymmetry in the geometric shapes were identified. Results Numerical results showed that talus bones are bilaterally symmetrical in nature, and the difference between the surface area of the left and right talus bones was less than 7.5%. Similarly, the difference in the volume of both bones was less than 7.5%. Results of the three-dimensional (3D) deviation analyses demonstrated the mean deviation between left and right talus bones were in the range of -0.74 mm to 0.62 mm. It was observed that in eight of 11 subjects, the deviation in symmetry occurred in regions that are clinically less important during talus surgery. Conclusions We conclude that left and right talus bones of intact human ankle joints show a strong degree of symmetry. The results of this study may have significance with respect to talus surgery, and in investigating traumatic talus injury where the geometric shape of the contralateral talus can be used as control. Cite this article: Bone Joint Res 2014;3:139–45. PMID:24802391

The Liquid State and Its Electrical Properties

DTIC Science & Technology

1988-01-01

system. At any instant, the density will deviate from its average, and the deviation of one position r will affect that at another position r’. These...and treats the affect of the sizes of the ions incompletely. The limiting law slopes and deviations from them depend strongly on the temperature and...2,2,4-trimethylpentane, pressure increases the mobility by 30-40% at room temperature, affects little change at temperatures near 60*, and decreases

Study on probability distribution of prices in electricity market: A case study of zhejiang province, china

NASA Astrophysics Data System (ADS)

Zhou, H.; Chen, B.; Han, Z. X.; Zhang, F. Q.

2009-05-01

The study on probability density function and distribution function of electricity prices contributes to the power suppliers and purchasers to estimate their own management accurately, and helps the regulator monitor the periods deviating from normal distribution. Based on the assumption of normal distribution load and non-linear characteristic of the aggregate supply curve, this paper has derived the distribution of electricity prices as the function of random variable of load. The conclusion has been validated with the electricity price data of Zhejiang market. The results show that electricity prices obey normal distribution approximately only when supply-demand relationship is loose, whereas the prices deviate from normal distribution and present strong right-skewness characteristic. Finally, the real electricity markets also display the narrow-peak characteristic when undersupply occurs.

Excitation laser energy dependence of surface-enhanced fluorescence showing plasmon-induced ultrafast electronic dynamics in dye molecules

NASA Astrophysics Data System (ADS)

Itoh, Tamitake; Yamamoto, Yuko S.; Tamaru, Hiroharu; Biju, Vasudevanpillai; Murase, Norio; Ozaki, Yukihiro

2013-06-01

We find unique properties accompanying surface-enhanced fluorescence (SEF) from dye molecules adsorbed on Ag nanoparticle aggregates, which generate surface-enhanced Raman scattering. The properties are observed in excitation laser energy dependence of SEF after excluding plasmonic spectral modulation in SEF. The unique properties are large blue shifts of fluorescence spectra, deviation of ratios between anti-Stokes SEF intensity and Stokes from those of normal fluorescence, super-broadening of Stokes spectra, and returning to original fluorescence by lower energy excitation. We elucidate that these properties are induced by electromagnetic enhancement of radiative decay rates exceeding the vibrational relaxation rates within an electronic excited state, which suggests that molecular electronic dynamics in strong plasmonic fields can be largely deviated from that in free space.

Anomalous interlayer vibrations in strongly coupled layered PdSe 2

DOE PAGES

Puretzky, Alexander A.; Oyedele, Akinola D.; Xiao, Kai; ...

2018-05-04

In this work, we show unusual effects of strong interlayer coupling on low-frequency (LF) Raman scattering in exfoliated PdSe 2 crystals with different number of layers. Unlike many other layered materials, it is found that the measured frequencies of the breathing modes cannot be simply described by a conventional linear chain model (LCM) that treats each layer as a single rigid object. By using first-principles calculations, we show that strong deviations from layer rigidity can occur for the LF breathing vibrations of PdSe 2, which accounts for the observed disagreement with the conventional LCM. The layer non-rigidity and strong interlayermore » coupling could also explain the unusual strong intensities of the LF breathing modes that are comparable with those of the high-frequency Raman modes. These strong intensities allowed us to use a set of the measured LF Raman lines as unique fingerprints for a precise assignment of the layer numbers. The assignment of the layer numbers was further confirmed using second harmonic generation that appeared only in the noncentrosymmetric even-layer PdSe 2 crystals. In conclusion, this work thus demonstrates a simple and fast approach for the determination of the number of layers in 2D materials with strong interlayer coupling and non-rigid interlayer vibrations.« less

Anomalous interlayer vibrations in strongly coupled layered PdSe 2

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

Puretzky, Alexander A.; Oyedele, Akinola D.; Xiao, Kai

In this work, we show unusual effects of strong interlayer coupling on low-frequency (LF) Raman scattering in exfoliated PdSe 2 crystals with different number of layers. Unlike many other layered materials, it is found that the measured frequencies of the breathing modes cannot be simply described by a conventional linear chain model (LCM) that treats each layer as a single rigid object. By using first-principles calculations, we show that strong deviations from layer rigidity can occur for the LF breathing vibrations of PdSe 2, which accounts for the observed disagreement with the conventional LCM. The layer non-rigidity and strong interlayermore » coupling could also explain the unusual strong intensities of the LF breathing modes that are comparable with those of the high-frequency Raman modes. These strong intensities allowed us to use a set of the measured LF Raman lines as unique fingerprints for a precise assignment of the layer numbers. The assignment of the layer numbers was further confirmed using second harmonic generation that appeared only in the noncentrosymmetric even-layer PdSe 2 crystals. In conclusion, this work thus demonstrates a simple and fast approach for the determination of the number of layers in 2D materials with strong interlayer coupling and non-rigid interlayer vibrations.« less

Spacetime and orbits of bumpy black holes

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

Vigeland, Sarah J.; Hughes, Scott A.

2010-01-15

Our Universe contains a great number of extremely compact and massive objects which are generally accepted to be black holes. Precise observations of orbital motion near candidate black holes have the potential to determine if they have the spacetime structure that general relativity demands. As a means of formulating measurements to test the black hole nature of these objects, Collins and Hughes introduced ''bumpy black holes'': objects that are almost, but not quite, general relativity's black holes. The spacetimes of these objects have multipoles that deviate slightly from the black hole solution, reducing to black holes when the deviation ismore » zero. In this paper, we extend this work in two ways. First, we show how to introduce bumps which are smoother and lead to better behaved orbits than those in the original presentation. Second, we show how to make bumpy Kerr black holes--objects which reduce to the Kerr solution when the deviation goes to zero. This greatly extends the astrophysical applicability of bumpy black holes. Using Hamilton-Jacobi techniques, we show how a spacetime's bumps are imprinted on orbital frequencies, and thus can be determined by measurements which coherently track the orbital phase of a small orbiting body. We find that in the weak field, orbits of bumpy black holes are modified exactly as expected from a Newtonian analysis of a body with a prescribed multipolar structure, reproducing well-known results from the celestial mechanics literature. The impact of bumps on strong-field orbits is many times greater than would be predicted from a Newtonian analysis, suggesting that this framework will allow observations to set robust limits on the extent to which a spacetime's multipoles deviate from the black hole expectation.« less

Temperature dependent structural properties and bending rigidity of pristine and defective hexagonal boron nitride

NASA Astrophysics Data System (ADS)

Thomas, Siby; Ajith, K. M.; Chandra, Sharat; Valsakumar, M. C.

2015-08-01

Structural and thermodynamical properties of monolayer pristine and defective boron nitride sheets (h-BN) have been investigated in a wide temperature range by carrying out atomistic simulations using a tuned Tersoff-type inter-atomic empirical potential. The temperature dependence of lattice parameter, radial distribution function, specific heat at constant volume, linear thermal expansion coefficient and the height correlation function of the thermally excited ripples on pristine as well as defective h-BN sheet have been investigated. Specific heat shows considerable increase beyond the Dulong-Petit limit at high temperatures, which is interpreted as a signature of strong anharmonicity present in h-BN. Analysis of the height fluctuations, < {{h}2}> , shows that the bending rigidity and variance of height fluctuations are strongly temperature dependent and this is explained using the continuum theory of membranes. A detailed study of the height-height correlation function shows deviation from the prediction of harmonic theory of membranes as a consequence of the strong anharmonicity in h-BN. It is also seen that the variance of the height fluctuations increases with defect concentration.

Fitness consequences of artificial selection on relative male genital size

PubMed Central

Booksmythe, Isobel; Head, Megan L.; Keogh, J. Scott; Jennions, Michael D.

2016-01-01

Male genitalia often show remarkable differences among related species in size, shape and complexity. Across poeciliid fishes, the elongated fin (gonopodium) that males use to inseminate females ranges from 18 to 53% of body length. Relative genital size therefore varies greatly among species. In contrast, there is often tight within-species allometric scaling, which suggests strong selection against genital–body size combinations that deviate from a species' natural line of allometry. We tested this constraint by artificially selecting on the allometric intercept, creating lines of males with relatively longer or shorter gonopodia than occur naturally for a given body size in mosquitofish, Gambusia holbrooki. We show that relative genital length is heritable and diverged 7.6–8.9% between our up-selected and down-selected lines, with correlated changes in body shape. However, deviation from the natural line of allometry does not affect male success in assays of attractiveness, swimming performance and, crucially, reproductive success (paternity). PMID:27188478

Numerical Large Deviation Analysis of the Eigenstate Thermalization Hypothesis

NASA Astrophysics Data System (ADS)

Yoshizawa, Toru; Iyoda, Eiki; Sagawa, Takahiro

2018-05-01

A plausible mechanism of thermalization in isolated quantum systems is based on the strong version of the eigenstate thermalization hypothesis (ETH), which states that all the energy eigenstates in the microcanonical energy shell have thermal properties. We numerically investigate the ETH by focusing on the large deviation property, which directly evaluates the ratio of athermal energy eigenstates in the energy shell. As a consequence, we have systematically confirmed that the strong ETH is indeed true even for near-integrable systems. Furthermore, we found that the finite-size scaling of the ratio of athermal eigenstates is a double exponential for nonintegrable systems. Our result illuminates the universal behavior of quantum chaos, and suggests that a large deviation analysis would serve as a powerful method to investigate thermalization in the presence of the large finite-size effect.

The impact of physical and mental tasks on pilot mental workoad

NASA Technical Reports Server (NTRS)

Berg, S. L.; Sheridan, T. B.

1986-01-01

Seven instrument-rated pilots with a wide range of backgrounds and experience levels flew four different scenarios on a fixed-base simulator. The Baseline scenario was the simplest of the four and had few mental and physical tasks. An activity scenario had many physical but few mental tasks. The Planning scenario had few physical and many mental taks. A Combined scenario had high mental and physical task loads. The magnitude of each pilot's altitude and airspeed deviations was measured, subjective workload ratings were recorded, and the degree of pilot compliance with assigned memory/planning tasks was noted. Mental and physical performance was a strong function of the manual activity level, but not influenced by the mental task load. High manual task loads resulted in a large percentage of mental errors even under low mental task loads. Although all the pilots gave similar subjective ratings when the manual task load was high, subjective ratings showed greater individual differences with high mental task loads. Altitude or airspeed deviations and subjective ratings were most correlated when the total task load was very high. Although airspeed deviations, altitude deviations, and subjective workload ratings were similar for both low experience and high experience pilots, at very high total task loads, mental performance was much lower for the low experience pilots.

The Higgs vacuum uplifted: revisiting the electroweak phase transition with a second Higgs doublet

NASA Astrophysics Data System (ADS)

Dorsch, G. C.; Huber, S. J.; Mimasu, K.; No, J. M.

2017-12-01

The existence of a second Higgs doublet in Nature could lead to a cosmological first order electroweak phase transition and explain the origin of the matter-antimatter asymmetry in the Universe. We explore the parameter space of such a two-Higgs-doublet-model and show that a first order electroweak phase transition strongly correlates with a significant uplifting of the Higgs vacuum w.r.t. its Standard Model value. We then obtain the spectrum and properties of the new scalars H 0, A 0 and H ± that signal such a phase transition, showing that the decay A 0 → H 0 Z at the LHC and a sizable deviation in the Higgs self-coupling λ hhh from its SM value are sensitive indicators of a strongly first order electroweak phase transition in the 2HDM.

Low-noise cold-field emission current obtained between two opposed carbon cone nanotips during in situ transmission electron microscope biasing

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

Knoop, L. de; Gatel, C.; Houdellier, F.

2015-06-29

A dedicated transmission electron microscope sample holder has been used to study in situ the cold-field emission process of carbon cone nanotips (CCnTs). We show that when using a CCnT instead of a Au plate-anode, the standard deviation of the emission current noise can be decreased from the 10 nA range to the 1 nA range under vacuum conditions of 10{sup −5 }Pa. This shows the strong influence of the anode on the cold-field emission current noise.

Impact of buildings on surface solar radiation over urban Beijing

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

Zhao, Bin; Liou, Kuo-Nan; Gu, Yu

The rugged surface of an urban area due to varying buildings can interact with solar beams and affect both the magnitude and spatiotemporal distribution of surface solar fluxes. Here we systematically examine the impact of buildings on downward surface solar fluxes over urban Beijing by using a 3-D radiation parameterization that accounts for 3-D building structures vs. the conventional plane-parallel scheme. We find that the resulting downward surface solar flux deviations between the 3-D and the plane-parallel schemes are generally ±1–10 W m -2 at 800 m grid resolution and within ±1 W m -2 at 4 km resolution. Pairsmore » of positive–negative flux deviations on different sides of buildings are resolved at 800 m resolution, while they offset each other at 4 km resolution. Flux deviations from the unobstructed horizontal surface at 4 km resolution are positive around noon but negative in the early morning and late afternoon. The corresponding deviations at 800 m resolution, in contrast, show diurnal variations that are strongly dependent on the location of the grids relative to the buildings. Both the magnitude and spatiotemporal variations of flux deviations are largely dominated by the direct flux. Furthermore, we find that flux deviations can potentially be an order of magnitude larger by using a finer grid resolution. Atmospheric aerosols can reduce the magnitude of downward surface solar flux deviations by 10–65 %, while the surface albedo generally has a rather moderate impact on flux deviations. The results imply that the effect of buildings on downward surface solar fluxes may not be critically significant in mesoscale atmospheric models with a grid resolution of 4 km or coarser. However, the effect can play a crucial role in meso-urban atmospheric models as well as microscale urban dispersion models with resolutions of 1 m to 1 km.« less

Contact Dependence and Velocity Crossover in Friction between Microscopic Solid/Solid Contacts.

PubMed

McGraw, Joshua D; Niguès, Antoine; Chennevière, Alexis; Siria, Alessandro

2017-10-11

Friction at the nanoscale differs markedly from that between surfaces of macroscopic extent. Characteristically, the velocity dependence of friction between apparent solid/solid contacts can strongly deviate from the classically assumed velocity independence. Here, we show that a nondestructive friction between solid tips with radius on the scale of hundreds of nanometers and solid hydrophobic self-assembled monolayers has a strong velocity dependence. Specifically, using laterally oscillating quartz tuning forks, we observe a linear scaling in the velocity at the lowest accessed velocities, typically hundreds of micrometers per second, crossing over into a logarithmic velocity dependence. This crossover is consistent with a general multicontact friction model that includes thermally activated breaking of the contacts at subnanometric elongation. We find as well a strong dependence of the friction on the dimensions of the frictional probe.

Correlation between Visual Field Index and Other Functional and Structural Measures in Glaucoma Patients and Suspects.

PubMed

Iutaka, Natalia A; Grochowski, Rubens A; Kasahara, Niro

2017-01-01

To evaluate the correlation between visual field index (VFI) and both structural and functional measures of the optic disc in primary open angle glaucoma patients and suspects. In this retrospective study, 162 glaucoma patients and suspects underwent standard automated perimetry (SAP), retinography, and retinal nerve fiber layer (RNFL) measurement. The optic disc was stratified according to the vertical cup/disc ratio (C/D) and sorted by the disc damage likelihood scale (DDLS). RNFL was measured with the optical coherence tomography. The VFI perimetry was correlated with the mean deviation (MD) and pattern standard deviation (PSD) obtained by SAP, and structural parameters by Pearson's correlation coefficients. VFI displayed strong correlation with MD ( R = 0.959) and PSD ( R = -0.744). The linear correlations between VFI and structural measures including C/D ( R = -0.179, P = 0.012), DDLS ( R = -0.214, P = 0.006), and RNFL ( R = 0.416, P < 0.001) were weak but statistically significant. VFI showed a strong correlation with MD and PSD but demonstrated a weak correlation with structural measures. It can possibly be used as a marker for functional impairment severity in patients with glaucoma.

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

Casadio, Roberto; Orlandi, Alessio; Kühnel, Florian, E-mail: casadio@bo.infn.it, E-mail: florian.kuhnel@fysik.su.se, E-mail: aorlandi@bo.infn.it

Following a new quantum cosmological model proposed by Dvali and Gomez, we quantitatively investigate possible modifications to the Hubble parameter and following corrections to the cosmic microwave background spectrum. In this model, scalar and tensor perturbations are generated by the quantum depletion of the background inflaton and graviton condensate respectively. We show how the inflaton mass affects the power spectra and the tensor-to-scalar ratio. Masses approaching the Planck scale would lead to strong deviations, while standard spectra are recovered for an inflaton mass much smaller than the Planck mass.

Nasal airway and septal variation in unilateral and bilateral cleft lip and palate.

PubMed

Starbuck, John M; Friel, Michael T; Ghoneima, Ahmed; Flores, Roberto L; Tholpady, Sunil; Kula, Katherine

2014-10-01

Cleft lip and palate (CLP) affects the dentoalveolar and nasolabial facial regions. Internal and external nasal dysmorphology may persist in individuals born with CLP despite surgical interventions. 7-18 year old individuals born with unilateral and bilateral CLP (n = 50) were retrospectively assessed using cone beam computed tomography. Anterior, middle, and posterior nasal airway volumes were measured on each facial side. Septal deviation was measured at the anterior and posterior nasal spine, and the midpoint between these two locations. Data were evaluated using principal components analysis (PCA), multivariate analysis of variance (MANOVA), and post-hoc ANOVA tests. PCA results show partial separation in high dimensional space along PC1 (48.5% variance) based on age groups and partial separation along PC2 (29.8% variance) based on CLP type and septal deviation patterns. MANOVA results indicate that age (P = 0.007) and CLP type (P ≤ 0.001) significantly affect nasal airway volume and septal deviation. ANOVA results indicate that anterior nasal volume is significantly affected by age (P ≤ 0.001), whereas septal deviation patterns are significantly affected by CLP type (P ≤ 0.001). Age and CLP type affect nasal airway volume and septal deviation patterns. Nasal airway volumes tend to be reduced on the clefted sides of the face relative to non-clefted sides of the face. Nasal airway volumes tend to strongly increase with age, whereas septal deviation values tend to increase only slightly with age. These results suggest that functional nasal breathing may be impaired in individuals born with the unilateral and bilateral CLP deformity. © 2014 Wiley Periodicals, Inc.

TESTING GRAVITY WITH QUASI-PERIODIC OSCILLATIONS FROM ACCRETING BLACK HOLES: THE CASE OF THE EINSTEIN–DILATON–GAUSS–BONNET THEORY

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

Maselli, Andrea; Gualtieri, Leonardo; Ferrari, Valeria

Quasi-periodic oscillations (QPOs) observed in the X-ray flux emitted by accreting black holes are associated with phenomena occurring near the horizon. Future very large area X-ray instruments will be able to measure QPO frequencies with very high precision, thus probing this strong-field region. Using the relativistic precession model, we show the way in which QPO frequencies could be used to test general relativity (GR) against those alternative theories of gravity which predict deviations from the classical theory in the strong-field and high-curvature regimes. We consider one of the best-motivated high-curvature corrections to GR, namely, the Einstein–Dilaton–Gauss–Bonnet theory, and show thatmore » a detection of QPOs with the expected sensitivity of the proposed ESA M-class mission LOFT would set the most stringent constraints on the parameter space of this theory.« less

Synchronization and bidirectional communication without delay line using strong mutually coupled semiconductor lasers

NASA Astrophysics Data System (ADS)

Li, Guang-Hui; Wang, An-Bang; Feng, Ye; Wang, Yang

2010-07-01

This paper numerically demonstrates synchronization and bidirectional communication without delay line by using two semiconductor lasers with strong mutual injection in a face-to-face configuration. These results show that both of the two lasers' outputs synchronize with their input chaotic carriers. In addition, simulations demonstrate that this kind of synchronization can be used to realize bidirectional communications without delay line. Further studies indicate that within a small deviation in message amplitudes of two sides (±6%), the message can be extracted with signal-noise-ratio more than 10 dB; and the signal-noise-ratio is extremely sensitive to the message rates mismatch of two sides, which may be used as a key of bidirectional communication.

Testing General Relativity with the Shadow Size of Sgr A(*).

PubMed

Johannsen, Tim; Broderick, Avery E; Plewa, Philipp M; Chatzopoulos, Sotiris; Doeleman, Sheperd S; Eisenhauer, Frank; Fish, Vincent L; Genzel, Reinhard; Gerhard, Ortwin; Johnson, Michael D

2016-01-22

In general relativity, the angular radius of the shadow of a black hole is primarily determined by its mass-to-distance ratio and depends only weakly on its spin and inclination. If general relativity is violated, however, the shadow size may also depend strongly on parametric deviations from the Kerr metric. Based on a reconstructed image of Sagittarius A^{*} (Sgr A^{*}) from a simulated one-day observing run of a seven-station Event Horizon Telescope (EHT) array, we employ a Markov chain Monte Carlo algorithm to demonstrate that such an observation can measure the angular radius of the shadow of Sgr A^{*} with an uncertainty of ∼1.5  μas (6%). We show that existing mass and distance measurements can be improved significantly when combined with upcoming EHT measurements of the shadow size and that tight constraints on potential deviations from the Kerr metric can be obtained.

The ‘ideal selectivity’ vs ‘true selectivity’ for permeation of gas mixture in nanoporous membranes

NASA Astrophysics Data System (ADS)

He, Zhou; Wang, Kean

2018-03-01

In this study, we proposed and validated a novel and non-destructive experimental technology for measuring the permeation of binary gas mixture in nanoporous membranes. The traditional time lag rig was modified to examine the permeation characteristics of each gas component as well as that of the binary gas mixtures. The difference in boiling points of each species were explored. Binary gas mixtures of CO2/He were permeated through the nanoporous carbon molecular sieve membrane (CMSM). The results showed that, due to the strong interaction among different molecules and with the porous network of the membrane, the measured perm-selectivity or ‘true selectivity’ of a binary mixture can significantly deviate from the ‘ideal selectivity’ calculated form the permeation flux of each pure species, and this deviation is a complicated function of the molecular properties and operation conditions.

A defect model for UO2+x based on electrical conductivity and deviation from stoichiometry measurements

NASA Astrophysics Data System (ADS)

Garcia, Philippe; Pizzi, Elisabetta; Dorado, Boris; Andersson, David; Crocombette, Jean-Paul; Martial, Chantal; Baldinozzi, Guido; Siméone, David; Maillard, Serge; Martin, Guillaume

2017-10-01

Electrical conductivity of UO2+x shows a strong dependence upon oxygen partial pressure and temperature which may be interpreted in terms of prevailing point defects. A simulation of this property along with deviation from stoichiometry is carried out based on a model that takes into account the presence of impurities, oxygen interstitials, oxygen vacancies, holes, electrons and clusters of oxygen atoms. The equilibrium constants for each defect reaction are determined to reproduce the experimental data. An estimate of defect concentrations and their dependence upon oxygen partial pressure can then be determined. The simulations carried out for 8 different temperatures (973-1673 K) over a wide range of oxygen partial pressures are discussed and resulting defect equilibrium constants are plotted in an Arrhenius diagram. This provides an estimate of defect formation energies which may further be compared to other experimental data or ab-initio and empirical potential calculations.

Mandibular deviations in TMD and non-TMD groups related to eye dominance and head posture.

PubMed

Pradham, N S; White, G E; Mehta, N; Forgione, A

2001-01-01

This study was designed to determine whether eye-dominance affects head posture (rotation) and in turn, whether head posture is associated with mandibular frenum midline deviation, in both TMJ and control subjects. Eye dominance was determined using three tests: Porta, Hole, Point tests. Natural head posture was evaluated using the Arthrodial protractor. Mandibular frenum deviation was recorded as left, right or no deviation. Fifty female subjects were included in the study, 25 TMJ patients attending the Gelb Craniomandibular Pain Center and 25 non-TMJ control subjects. The findings indicate that eye dominance and direction of head rotation are strongly associated in both TMJ and control subjects. Further, in TMJ subjects mandibular deviation occurred in greater frequency than in controls and tends to occur in the contra lateral direction of head rotation.

Coercivity of die upset NdFeB magnets: A strong pinning model

NASA Astrophysics Data System (ADS)

Pinkerton, F. E.; Fuerst, C. D.

1990-09-01

We show that the temperature dependence of the intrinsic coercivity Hci( T) between 5 and 600 K in a die-upset NdFeB magnet is in good agreement with a model for strong domain wall pinning by a random array of pinning sites proposed by Gaunt [P. Gaunt, Phil. Mag. B48 (1983) 261]. The model includes both the temperature dependence of the intrinsic magnetic properties of the Nd 2Fe 14B phase and the effects of thermal activation of domain walls over the pinning barrier. The pinning sites are modeled as nonmagnetic planar inhomogeneities at the boundaries aetween platelet-shaped Nd 2Fe 14B grains. We develop an expression for the maximum pinning force per site, f, and derive the model prediction that (H ci/γH A) {1}/{2} varies linearly with (T/γ) {2}/{3}, where HA and γ are the magnetocrystalline anisotropy and the domain wall energy per unit area of the Nd 2Fe 14B phase, respectively. The model is in good agreement with the observed Hci values over a broad temperature range from 200 to 477 K. Deviations from the model below 200 K are an artifact of the axial-to-conical spin reorientation in Nd 2Fe 14B at low temperature. Deviations at high temperature most likely occur because the strong pinning model is no longer valid close to the Curie temperature (585 K).

Scalar-tensor theories and modified gravity in the wake of GW170817

NASA Astrophysics Data System (ADS)

Langlois, David; Saito, Ryo; Yamauchi, Daisuke; Noui, Karim

2018-03-01

Theories of dark energy and modified gravity can be strongly constrained by astrophysical or cosmological observations, as illustrated by the recent observation of the gravitational wave event GW170817 and of its electromagnetic counterpart GRB 170817A, which showed that the speed of gravitational waves, cg , is the same as the speed of light, within deviations of order 10-15 . This observation implies severe restrictions on scalar-tensor theories, in particular theories whose action depends on second derivatives of a scalar field. Working in the very general framework of degenerate higher-order scalar-tensor (DHOST) theories, which encompass Horndeski and beyond Horndeski theories, we present the DHOST theories that satisfy cg=c . We then examine, for these theories, the screening mechanism that suppresses scalar interactions on small scales, namely the Vainshtein mechanism, and compute the corresponding gravitational laws for a nonrelativistic spherical body. We show that it can lead to a deviation from standard gravity inside matter, parametrized by three coefficients which satisfy a consistency relation and can be constrained by present and future astrophysical observations.

A Visual Model for the Variance and Standard Deviation

ERIC Educational Resources Information Center

Orris, J. B.

2011-01-01

This paper shows how the variance and standard deviation can be represented graphically by looking at each squared deviation as a graphical object--in particular, as a square. A series of displays show how the standard deviation is the size of the average square.

Strong adherence to a healthy dietary pattern is associated with better semen quality, especially in men with poor semen quality.

PubMed

Oostingh, Elsje C; Steegers-Theunissen, Régine P M; de Vries, Jeanne H M; Laven, Joop S E; Koster, Maria P H

2017-04-01

To study associations between periconceptional dietary patterns and semen quality parameters. Prospective periconception cohort study. Tertiary hospital. One hundred and twenty-nine male partners of pregnant women who participated in the Rotterdam Periconception Cohort (Predict study). None. Semen quality parameters-ejaculate volume, sperm concentration, total sperm count, progressive motility, immotile sperm, and total motile sperm count (TMSC). Men included in our study were on average 35 (±6 standard deviation) years old and had a body mass index of 26.4 ± 4 kg/m 2 . Two dietary patterns were identified using principle component analysis, which were labeled as "healthy" and "unhealthy." An increase of one factor score (stated as β) represented an increase of 1 standard deviation. Sperm concentration (β = 0.278; 95% CI, 0.112-0.444), total sperm count (β = 1.369; 95% CI, 0.244-2.495), progressive motility (β = 4.305; 95% CI, 0.675-7.936), and TMSC (β = 0.319; 95% CI, 0.113-0.526) were all positively associated with a strong adherence to the healthy dietary pattern. Subgroup analysis showed that these associations were mainly present in men with a TMSC <10 million spermatozoa. Although there was a trend toward a diminution in semen quality, we found no statistically significant associations with strong adherence to the unhealthy dietary pattern. The positive associations between strong adherence to a healthy dietary pattern and semen parameters in men with poor semen quality support the importance of preconceptional tailored nutritional counseling and coaching of couples who are trying to conceive. Copyright © 2017 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Properties of pattern standard deviation in open-angle glaucoma patients with hemi-optic neuropathy and bi-optic neuropathy.

PubMed

Heo, Dong Won; Kim, Kyoung Nam; Lee, Min Woo; Lee, Sung Bok; Kim, Chang-Sik

2017-01-01

To evaluate the properties of pattern standard deviation (PSD) according to localization of the glaucomatous optic neuropathy. We enrolled 242 eyes of 242 patients with primary open-angle glaucoma, with a best-corrected visual acuity ≥ 20/25, and no media opacity. Patients were examined via dilated fundus photography, spectral-domain optical coherence tomography, and Humphrey visual field examination, and divided into those with hemi-optic neuropathy (superior or inferior) and bi-optic neuropathy (both superior and inferior). We assessed the relationship between mean deviation (MD) and PSD. Using broken stick regression analysis, the tipping point was identified, i.e., the point at which MD became significantly associated with a paradoxical reversal of PSD. In 91 patients with hemi-optic neuropathy, PSD showed a strong correlation with MD (r = -0.973, β = -0.965, p < 0.001). The difference between MD and PSD ("-MD-PSD") was constant (mean, -0.32 dB; 95% confidence interval, -2.48~1.84 dB) regardless of visual field defect severity. However, in 151 patients with bi-optic neuropathy, a negative correlation was evident between "-MD-PSD" and MD (r2 = 0.907, p < 0.001). Overall, the MD tipping point was -14.0 dB, which was close to approximately 50% damage of the entire visual field (p < 0.001). Although a false decrease of PSD usually begins at approximately 50% visual field damage, in patients with hemi-optic neuropathy, the PSD shows no paradoxical decrease and shows a linear correlation with MD.

Beyond Word Frequency: Bursts, Lulls, and Scaling in the Temporal Distributions of Words

PubMed Central

Altmann, Eduardo G.; Pierrehumbert, Janet B.; Motter, Adilson E.

2009-01-01

Background Zipf's discovery that word frequency distributions obey a power law established parallels between biological and physical processes, and language, laying the groundwork for a complex systems perspective on human communication. More recent research has also identified scaling regularities in the dynamics underlying the successive occurrences of events, suggesting the possibility of similar findings for language as well. Methodology/Principal Findings By considering frequent words in USENET discussion groups and in disparate databases where the language has different levels of formality, here we show that the distributions of distances between successive occurrences of the same word display bursty deviations from a Poisson process and are well characterized by a stretched exponential (Weibull) scaling. The extent of this deviation depends strongly on semantic type – a measure of the logicality of each word – and less strongly on frequency. We develop a generative model of this behavior that fully determines the dynamics of word usage. Conclusions/Significance Recurrence patterns of words are well described by a stretched exponential distribution of recurrence times, an empirical scaling that cannot be anticipated from Zipf's law. Because the use of words provides a uniquely precise and powerful lens on human thought and activity, our findings also have implications for other overt manifestations of collective human dynamics. PMID:19907645

Evolution of Grain Interfaces in Annealed Duplex Stainless Steel after Parallel Cross Rolling and Direct Rolling

PubMed Central

Wang, Ming; Li, Haoqing; Tian, Yujing; Guo, Hong; Fang, Xiaoying; Guo, Yuebin

2018-01-01

Changes in various grain interfaces, including the grain boundary and phase boundary, are a strong indication of microstructural changes, particularly ultra-fined grains achieved by large strain deformation and subsequent annealing. After direct rolling and cross rolling with the same strain of ε = 2, the distributions of the interfaces in annealed UNS S32304 duplex stainless steel were investigated using electron backscatter diffraction (EBSD) in this study. The ferrite experienced continued recovery, and a high density of low-angle grain boundaries (LAGBs) was produced. The percentage and number of twin boundaries (TBs) and LAGBs varied within the austenite. TBs were frequently found within austenite, showing a deviation from the Kurdjumov-Sachs (K-S) orientation relationship (OR) with ferrite matrix. However, LAGBs usually occur in austenite, with the K-S OR in the ferrite matrix. LAGBs were prevalent in the precipitated austenite grains, and therefore a strong texture was introduced in the cross-rolled and annealed samples, in which the precipitated austenite readily maintained the K-S OR in the ferrite matrix. By contrast, more TBs and a less robust texture were found in the precipitated austenite in direct-rolled and annealed samples, deviating from the K-S OR. PMID:29772723

Probing anomalous $$ t\\overline{t}Z $$ interactions with rare meson decays

DOE PAGES

Brod, Joachim; Greljo, Admir; Stamou, Emmanuel; ...

2015-02-23

Anomalous couplings of the Z boson to top quarks are only marginally constrained by direct searches and are still sensitive to new particle dynamics at the TeV scale. Employing an effective field theory approach we consider the dimension-six operators which generate deviations from the standard-model vector and axial-vector interactions. We show that rare B and K meson decays together with electroweak precision observables provide strong constraints on these couplings. In addition, we also consider constraints from t-channel single-top production.

Spin-exchange effects in elastic electron-radical collisions

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

Fujimoto, M. M.; Michelin, S. E.; Iga, I.

2006-01-15

This work presents a theoretical investigation on the spin-exchange effects in the low-energy elastic electron-C{sub 2}O radical collisions. Spin-polarization differential and integral cross sections calculated in the 1-10-eV energy range are reported. Our calculation has shown that the exchange between the scattering and unpaired target electron is strongly influenced by the occurrence of shape resonances. More specifically, our calculated rotationally summed spin-polarization fractions show significant deviation from unity in the resonance region. An analysis of the contributions from individual rotational transitions is also made.

Frank Wilczek, Asymptotic Freedom, and Strong Interaction

Science.gov Websites

whereby quarks behave as free particles when they are close together, but become more strongly attracted , Issue 26; 1973 Asymptotically Free Gauge Theories I; DOE Technical Report; 1973 Scaling Deviations for Neutrino Reactions in Asymptotically Free Field Theories; DOE Technical Report; 1974 Weak-interaction

Interhemispheric Asymmetry of the Sunward Plasma Flows for Strongly Dominant IMF BZ > 0

NASA Astrophysics Data System (ADS)

Yakymenko, K. N.; Koustov, A. V.; Fiori, R. A. D.

2018-01-01

Super Dual Auroral Radar Network (SuperDARN) convection maps obtained simultaneously in both hemispheres are averaged to infer polar cap ionospheric flow patterns under strongly dominant positive interplanetary magnetic field (IMF) Bz component. The data set consisted of winter observations in the Northern Hemisphere simultaneously with summer observations in the Southern Hemisphere. Long-lasting high-latitude dayside reverse convection cells are shown to have faster sunward flows at near-magnetic noon hours in the summer/Southern Hemisphere. Sunward flows typically deviate from the midnight-noon meridian toward 10-11 h of magnetic local time in the summer/Southern Hemisphere and are more aligned with the midnight-noon meridian in the winter/Northern Hemisphere. Flow deviations in the winter/Northern Hemisphere can be both toward prenoon and postnoon hours, and there is no clear relationship between flow deviation and the IMF By component. No strong preference for the sunward flow occurrence depending on the IMF Bx polarity was found. In addition, the rate of the sunward flow speed increase in response to an increase in driving conditions was found to be comparable for the IMF Bx > 0 and Bx < 0.

Quantifying the heterogeneity of the tectonic stress field using borehole data

USGS Publications Warehouse

Schoenball, Martin; Davatzes, Nicholas C.

2017-01-01

The heterogeneity of the tectonic stress field is a fundamental property which influences earthquake dynamics and subsurface engineering. Self-similar scaling of stress heterogeneities is frequently assumed to explain characteristics of earthquakes such as the magnitude-frequency relation. However, observational evidence for such scaling of the stress field heterogeneity is scarce.We analyze the local stress orientations using image logs of two closely spaced boreholes in the Coso Geothermal Field with sub-vertical and deviated trajectories, respectively, each spanning about 2 km in depth. Both the mean and the standard deviation of stress orientation indicators (borehole breakouts, drilling-induced fractures and petal-centerline fractures) determined from each borehole agree to the limit of the resolution of our method although measurements at specific depths may not. We find that the standard deviation in these boreholes strongly depends on the interval length analyzed, generally increasing up to a wellbore log length of about 600 m and constant for longer intervals. We find the same behavior in global data from the World Stress Map. This suggests that the standard deviation of stress indicators characterizes the heterogeneity of the tectonic stress field rather than the quality of the stress measurement. A large standard deviation of a stress measurement might be an expression of strong crustal heterogeneity rather than of an unreliable stress determination. Robust characterization of stress heterogeneity requires logs that sample stress indicators along a representative sample volume of at least 1 km.

Guided waves and defect scattering in metal matrix composite plates

NASA Technical Reports Server (NTRS)

Datta, Subhendu K.; Bratton, Robert L.; Shah, Arvind H.

1989-01-01

Guided Rayleigh-Lamb waves in a continuous graphite fiber reinforced magnesium plate has been studied. The interest in this material arises from its high thermal stability and because it provides high strength-to-weight ratio. Previous studies have shown that for wavelengths much larger than the fiber diameters and spacing, the material can be characterized as transversely isotropic with the symmetry axis aligned with the fiber direction. Because of the high longitudinal stiffness of the graphite fibers, the material shows strong anisotropy, with very high modulus in the fiber direction. For this reason, dispersion of guided waves is strongly influenced by the deviation of the direction of propagation from the symmetry axis. Results are given for propagation in different directions and for scattering of antiplane shear waves by surface-breaking cracks and delaminations.

Neutron star merger GW170817 strongly constrains doubly coupled bigravity

NASA Astrophysics Data System (ADS)

Akrami, Yashar; Brax, Philippe; Davis, Anne-Christine; Vardanyan, Valeri

2018-06-01

We study the implications of the recent detection of gravitational waves emitted by a pair of merging neutron stars and their electromagnetic counterpart, events GW170817 and GRB170817A, on the viability of the doubly coupled bimetric models of cosmic evolution, where the two metrics couple directly to matter through a composite, effective metric. We demonstrate that the bounds on the speed of gravitational waves place strong constraints on the doubly coupled models, forcing either the two metrics to be proportional at the background level or the models to become singly coupled. Proportional backgrounds are particularly interesting as they provide stable cosmological solutions with phenomenologies equivalent to that of Λ CDM at the background level as well as for linear perturbations, while nonlinearities are expected to show deviations from the standard model.

Lunar Laser Ranging Science: Gravitational Physics and Lunar Interior and Geodesy

NASA Technical Reports Server (NTRS)

Williams, James G.; Turyshev, Slava G.; Boggs, Dale H.; Ratcliff, J. Todd

2004-01-01

Laser pulses fired at retroreflectors on the Moon provide very accurate ranges. Analysis yields information on Earth, Moon, and orbit. The highly accurate retroreflector positions have uncertainties less than a meter. Tides on the Moon show strong dissipation, with Q=33+/-4 at a month and a weak dependence on period. Lunar rotation depends on interior properties; a fluid core is indicated with radius approx.20% that of the Moon. Tests of relativistic gravity verify the equivalence principle to +/-1.4x10(exp -13), limit deviations from Einstein's general relativity, and show no rate for the gravitational constant G/G with uncertainty 9x10(exp -13)/yr.

Charge transfer excitations from exact and approximate ensemble Kohn-Sham theory

NASA Astrophysics Data System (ADS)

Gould, Tim; Kronik, Leeor; Pittalis, Stefano

2018-05-01

By studying the lowest excitations of an exactly solvable one-dimensional soft-Coulomb molecular model, we show that components of Kohn-Sham ensembles can be used to describe charge transfer processes. Furthermore, we compute the approximate excitation energies obtained by using the exact ensemble densities in the recently formulated ensemble Hartree-exchange theory [T. Gould and S. Pittalis, Phys. Rev. Lett. 119, 243001 (2017)]. Remarkably, our results show that triplet excitations are accurately reproduced across a dissociation curve in all cases tested, even in systems where ground state energies are poor due to strong static correlations. Singlet excitations exhibit larger deviations from exact results but are still reproduced semi-quantitatively.

Wall-collision line broadening of molecular oxygen within nanoporous materials

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

Xu, Can T.; Lewander, Maerta; Andersson-Engels, Stefan

2011-10-15

Wall-collision broadening of near-infrared absorption lines of molecular oxygen confined in nanoporous zirconia is studied by employing high-resolution diode-laser spectroscopy. The broadening is studied for pores of different sizes under a range of pressures, providing new insights on how wall collisions and intermolecular collisions influence the total spectroscopic line profile. The pressure series show that wall-collision broadening is relatively more prominent under reduced pressures, enabling sensitive means to probe pore sizes of porous materials. In addition, we show that the total wall-collision-broadened profile strongly deviates from a Voigt profile and that wall-collision broadening exhibits an additive-like behavior to the pressuremore » and Doppler broadening.« less

Accurate control of a liquid-crystal display to produce a homogenized Fourier transform for holographic memories.

PubMed

Márquez, Andrés; Gallego, Sergi; Méndez, David; Alvarez, Mariela L; Fernández, Elena; Ortuño, Manuel; Neipp, Cristian; Beléndez, Augusto; Pascual, Inmaculada

2007-09-01

We show an accurate procedure to obtain a Fourier transform (FT) with no dc term using a commercial twisted-nematic liquid-crystal display. We focus on the application to holographic storage of binary data pages, where a drastic decrease of the dc term in the FT is highly desirable. Two different codification schemes are considered: binary pi radians phase modulation and hybrid ternary modulation. Any deviation in the values of the amplitude and phase shift generates the appearance of a strong dc term. Experimental results confirm that the calculated configurations provide a FT with no dc term, thus showing the effectiveness of the proposal.

Thermodynamics of enzyme-catalyzed esterifications: II. Levulinic acid esterification with short-chain alcohols.

PubMed

Altuntepe, Emrah; Emel'yanenko, Vladimir N; Forster-Rotgers, Maximilian; Sadowski, Gabriele; Verevkin, Sergey P; Held, Christoph

2017-10-01

Levulinic acid was esterified with methanol, ethanol, and 1-butanol with the final goal to predict the maximum yield of these equilibrium-limited reactions as function of medium composition. In a first step, standard reaction data (standard Gibbs energy of reaction Δ R g 0 ) were determined from experimental formation properties. Unexpectedly, these Δ R g 0 values strongly deviated from data obtained with classical group contribution methods that are typically used if experimental standard data is not available. In a second step, reaction equilibrium concentrations obtained from esterification catalyzed by Novozym 435 at 323.15 K were measured, and the corresponding activity coefficients of the reacting agents were predicted with perturbed-chain statistical associating fluid theory (PC-SAFT). The so-obtained thermodynamic activities were used to determine Δ R g 0 at 323.15 K. These results could be used to cross-validate Δ R g 0 from experimental formation data. In a third step, reaction-equilibrium experiments showed that equilibrium position of the reactions under consideration depends strongly on the concentration of water and on the ratio of levulinic acid: alcohol in the initial reaction mixtures. The maximum yield of the esters was calculated using Δ R g 0 data from this work and activity coefficients of the reacting agents predicted with PC-SAFT for varying feed composition of the reaction mixtures. The use of the new Δ R g 0 data combined with PC-SAFT allowed good agreement to the measured yields, while predictions based on Δ R g 0 values obtained with group contribution methods showed high deviations to experimental yields.

Free Dendritic Growth of Succinonitrile-Acetone Alloys with Thermosolutal Melt Convection

NASA Technical Reports Server (NTRS)

Beckermann, Christoph; Li, Ben Q.

2003-01-01

A stagnant film model of the effects of thermosolutal convection on free dendritic growth of alloys is developed, and its predictions are compared to available earth-based experimental data for succinonitrileacetone alloys. It is found that the convection model gives excellent agreement with the measured dendrite tip velocities and radii for low solute concentrations. However, at higher solute concentrations the present predictions show some deviations from the measured data, and the measured (thermal) Peclet numbers tend to fall even below the predictions from diffusion theory. Furthermore, the measured selection parameter (sigma*) is significantly above the expected value of 0.02 and exhibits strong scatter. It is shown that convection is not responsible for these discrepancies. Some of the deviations between the predicted and measured data at higher supercoolings could be caused by measurement difficulties. The systematic disagreement in the selection parameter for higher solute concentrations and all supercoolings examined, indicates that the theory for the selection of the dendrite tip operating state in alloys may need to be reexamined.

Minding Impacting Events in a Model of Stochastic Variance

PubMed Central

Duarte Queirós, Sílvio M.; Curado, Evaldo M. F.; Nobre, Fernando D.

2011-01-01

We introduce a generalization of the well-known ARCH process, widely used for generating uncorrelated stochastic time series with long-term non-Gaussian distributions and long-lasting correlations in the (instantaneous) standard deviation exhibiting a clustering profile. Specifically, inspired by the fact that in a variety of systems impacting events are hardly forgot, we split the process into two different regimes: a first one for regular periods where the average volatility of the fluctuations within a certain period of time is below a certain threshold, , and another one when the local standard deviation outnumbers . In the former situation we use standard rules for heteroscedastic processes whereas in the latter case the system starts recalling past values that surpassed the threshold. Our results show that for appropriate parameter values the model is able to provide fat tailed probability density functions and strong persistence of the instantaneous variance characterized by large values of the Hurst exponent (), which are ubiquitous features in complex systems. PMID:21483864

Brief communication: Swimming and diving behavior in apes (Pan troglodytes and Pongo pygmaeus): first documented report.

PubMed

Bender, Renato; Bender, Nicole

2013-09-01

Extant hominoids, including humans, are well known for their inability to swim instinctively. We report swimming and diving in two captive apes using visual observation and video recording. One common chimpanzee and one orangutan swam repeatedly at the water surface over a distance of 2-6 m; both individuals submerged repeatedly. We show that apes are able to overcome their negative buoyancy by deliberate swimming, using movements which deviate from the doggy-paddle pattern observed in other primates. We suggest that apes' poor swimming ability is due to behavioral, anatomical, and neuromotor changes related to an adaptation to arboreal life in their early phylogeny. This strong adaptive focus on arboreal life led to decreased opportunities to interact with water bodies and consequently to a reduction of selective pressure to maintain innate swimming behavior. As the doggy paddle is associated with quadrupedal walking, a deviation from terrestrial locomotion might have interfered with the fixed rhythmic action patterns responsible for innate swimming. Copyright © 2013 Wiley Periodicals, Inc.

Attacks exploiting deviation of mean photon number in quantum key distribution and coin tossing

NASA Astrophysics Data System (ADS)

Sajeed, Shihan; Radchenko, Igor; Kaiser, Sarah; Bourgoin, Jean-Philippe; Pappa, Anna; Monat, Laurent; Legré, Matthieu; Makarov, Vadim

2015-03-01

The security of quantum communication using a weak coherent source requires an accurate knowledge of the source's mean photon number. Finite calibration precision or an active manipulation by an attacker may cause the actual emitted photon number to deviate from the known value. We model effects of this deviation on the security of three quantum communication protocols: the Bennett-Brassard 1984 (BB84) quantum key distribution (QKD) protocol without decoy states, Scarani-Acín-Ribordy-Gisin 2004 (SARG04) QKD protocol, and a coin-tossing protocol. For QKD we model both a strong attack using technology possible in principle and a realistic attack bounded by today's technology. To maintain the mean photon number in two-way systems, such as plug-and-play and relativistic quantum cryptography schemes, bright pulse energy incoming from the communication channel must be monitored. Implementation of a monitoring detector has largely been ignored so far, except for ID Quantique's commercial QKD system Clavis2. We scrutinize this implementation for security problems and show that designing a hack-proof pulse-energy-measuring detector is far from trivial. Indeed, the first implementation has three serious flaws confirmed experimentally, each of which may be exploited in a cleverly constructed Trojan-horse attack. We discuss requirements for a loophole-free implementation of the monitoring detector.

Anomalous dynamics of interstitial dopants in soft crystals

PubMed Central

Tauber, Justin; Higler, Ruben; Sprakel, Joris

2016-01-01

The dynamics of interstitial dopants govern the properties of a wide variety of doped crystalline materials. To describe the hopping dynamics of such interstitial impurities, classical approaches often assume that dopant particles do not interact and travel through a static potential energy landscape. Here we show, using computer simulations, how these assumptions and the resulting predictions from classical Eyring-type theories break down in entropically stabilized body-centered cubic (BCC) crystals due to the thermal excitations of the crystalline matrix. Deviations are particularly severe close to melting where the lattice becomes weak and dopant dynamics exhibit strongly localized and heterogeneous dynamics. We attribute these anomalies to the failure of both assumptions underlying the classical description: (i) The instantaneous potential field experienced by dopants becomes largely disordered due to thermal fluctuations and (ii) elastic interactions cause strong dopant–dopant interactions even at low doping fractions. These results illustrate how describing nonclassical dopant dynamics requires taking the effective disordered potential energy landscape of strongly excited crystals and dopant–dopant interactions into account. PMID:27856751

How does an asymmetric magnetic field change the vertical structure of a hot accretion flow?

NASA Astrophysics Data System (ADS)

Samadi, M.; Abbassi, S.; Lovelace, R. V. E.

2017-09-01

This paper explores the effects of large-scale magnetic fields in hot accretion flows for asymmetric configurations with respect to the equatorial plane. The solutions that we have found show that the large-scale asymmetric magnetic field can significantly affect the dynamics of the flow and also cause notable outflows in the outer parts. Previously, we treated a viscous resistive accreting disc in the presence of an odd symmetric B-field about the equatorial plane. Now, we extend our earlier work by taking into account another configuration of large-scale magnetic field that is no longer symmetric. We provide asymmetric field structures with small deviations from even and odd symmetric B-field. Our results show that the disc's dynamics and appearance become different above and below the equatorial plane. The set of solutions also predicts that even a small deviation in a symmetric field causes the disc to compress on one side and expand on the other. In some cases, our solution represents a very strong outflow from just one side of the disc. Therefore, the solution may potentially explain the origin of one-sided jets in radio galaxies.

A programmable and self-adjusting class E amplifier for efficient wireless powering of biomedical implants.

PubMed

Stoecklin, S; Volk, T; Yousaf, A; Reindl, L

2015-01-01

In this paper, an enhanced approach of a class E amplifier being insensitive to coil impedance variations is presented. While state of the art class E amplifiers widely being used to supply implanted systems show a strong degradation of efficiency when powering distance, coil orientation or the implant current consumption deviate from the nominal design, the presented concept is able to detect these deviations on-line and to reconfigure the amplifier automatically. The concept is facilitated by a new approach of sensing the load impedance without interruption of the power supply to the implant, while the main components of the class E amplifier are programmable by software. Therefore, the device is able to perform dynamic impedance matching. Besides presenting the operational principle and the design equations, we show an adaptive prototype reader system which achieves a drain efficiency of up to 92% for a wide range of reflected coil impedances from 1 to 40 Ω. The integrated communication concept allows downlink data rates of up to 500 kBit/s, while the load modulation based uplink from implant to reader was verified of providing up to 1.35 MBit/s.

Thermal stability of mullite RMn₂O₅ (R  =  Bi, Y, Pr, Sm or Gd): combined density functional theory and experimental study.

PubMed

Li, Chenzhe; Thampy, Sampreetha; Zheng, Yongping; Kweun, Joshua M; Ren, Yixin; Chan, Julia Y; Kim, Hanchul; Cho, Maenghyo; Kim, Yoon Young; Hsu, Julia W P; Cho, Kyeongjae

2016-03-31

Understanding and effectively predicting the thermal stability of ternary transition metal oxides with heavy elements using first principle simulations are vital for understanding performance of advanced materials. In this work, we have investigated the thermal stability of mullite RMn2O5 (R  =  Bi, Pr, Sm, or Gd) structures by constructing temperature phase diagrams using an efficient mixed generalized gradient approximation (GGA) and the GGA  +  U method. Simulation predicted stability regions without corrections on heavy elements show a 4-200 K underestimation compared to our experimental results. We have found the number of d/f electrons in the heavy elements shows a linear relationship with the prediction deviation. Further correction on the strongly correlated electrons in heavy elements could significantly reduce the prediction deviations. Our corrected simulation results demonstrate that further correction of R-site elements in RMn2O5 could effectively reduce the underestimation of the density functional theory-predicted decomposition temperature to within 30 K. Therefore, it could produce an accurate thermal stability prediction for complex ternary transition metal oxide compounds with heavy elements.

Reproducibility of Fluorescent Expression from Engineered Biological Constructs in E. coli

PubMed Central

Beal, Jacob; Haddock-Angelli, Traci; Gershater, Markus; de Mora, Kim; Lizarazo, Meagan; Hollenhorst, Jim; Rettberg, Randy

2016-01-01

We present results of the first large-scale interlaboratory study carried out in synthetic biology, as part of the 2014 and 2015 International Genetically Engineered Machine (iGEM) competitions. Participants at 88 institutions around the world measured fluorescence from three engineered constitutive constructs in E. coli. Few participants were able to measure absolute fluorescence, so data was analyzed in terms of ratios. Precision was strongly related to fluorescent strength, ranging from 1.54-fold standard deviation for the ratio between strong promoters to 5.75-fold for the ratio between the strongest and weakest promoter, and while host strain did not affect expression ratios, choice of instrument did. This result shows that high quantitative precision and reproducibility of results is possible, while at the same time indicating areas needing improved laboratory practices. PMID:26937966

Stable isotope chemistry of fossil bone as a new paleoclimate indicator

NASA Astrophysics Data System (ADS)

Kohn, Matthew J.; Law, J. Mclver

2006-02-01

During fossilization, bone is thought to recrystallize and alter chemically on timescales of kyr to a few tens of kyr, i.e., similar to the timescale for formation of soils. Therefore, C- and O-isotope compositions of bone apatite should correlate with trends in soil water composition and aridity, and serve as paleoclimate indicators. This hypothesis was tested by analyzing C- and O-isotope compositions of the CO 3 component of fossil bone apatite from mid-Oligocene through late Pleistocene units in Oregon and western Idaho, including the John Day (19.4-30.0 Ma), Mascall (15.2-15.8 Ma), and Rattlesnake (7.2-7.8 Ma) Formations, whose paleosol sequences have been studied in detail, and the Juntura (10-11 Ma), Hagerman (3.2 Ma), and Fossil Lake (<23-650 ka) fossil localities. Tooth enamel δ18O values provide a baseline of meteoric water compositions. Stable isotope compositions of bone CO 3 do change in response to broad climatic trends, but show poor correlation with compositions of corresponding paleosol CO 3 at specific horizons. Instead, compositional deviations between bone and paleosol CO 3 correlate with compositional deviations with the next higher paleosol; this suggests that the timescale for fossilization exceeds one paleosol cycle. Based on stratigraphic evidence and simple alteration models, fossilization timescales are estimated at 20-50 kyr, indicating that bone CO 3 will prove most useful for sequences spanning >100 kyr. C-isotopes show negative and strong positive deviations during wet and dry climates respectively, and short-term trends correspond well with changes in aridity within the Mascall and Rattlesnake Formations, as inferred from paleosols. A proposed correction to δ18O values based on δ13C anomalies implies a small, ˜1.5‰ increase in meteoric water δ18O during the late Oligocene global warming event, consistent with a minimum temperature increase of ˜4 °C. A strong inferred decrease in δ18O of 4-5‰ after 7 Ma closely parallels compositional changes in tooth enamel, and reflects a doubling in the height of the Cascade Range.

TRANSIT TIMING OBSERVATIONS FROM KEPLER. VI. POTENTIALLY INTERESTING CANDIDATE SYSTEMS FROM FOURIER-BASED STATISTICAL TESTS

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

Steffen, Jason H.; Ford, Eric B.; Rowe, Jason F.

2012-09-10

We analyze the deviations of transit times from a linear ephemeris for the Kepler Objects of Interest (KOI) through quarter six of science data. We conduct two statistical tests for all KOIs and a related statistical test for all pairs of KOIs in multi-transiting systems. These tests identify several systems which show potentially interesting transit timing variations (TTVs). Strong TTV systems have been valuable for the confirmation of planets and their mass measurements. Many of the systems identified in this study should prove fruitful for detailed TTV studies.

Transit Timing Observations from Kepler: VII. Potentially interesting candidate systems from Fourier-based statistical tests

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

Steffen, Jason H.; /Fermilab; Ford, Eric B.

2012-01-01

We analyze the deviations of transit times from a linear ephemeris for the Kepler Objects of Interest (KOI) through Quarter six (Q6) of science data. We conduct two statistical tests for all KOIs and a related statistical test for all pairs of KOIs in multi-transiting systems. These tests identify several systems which show potentially interesting transit timing variations (TTVs). Strong TTV systems have been valuable for the confirmation of planets and their mass measurements. Many of the systems identified in this study should prove fruitful for detailed TTV studies.

Software Obfuscation With Symmetric Cryptography

DTIC Science & Technology

2008-03-01

of y = a * b + c Against Random Functions ...............84 Appendix C: Black-box Analysis of Fibonacci Against Random Functions...Metric ................... 67 Figure 19. Standard Deviations of All Fibonacci Output Bits by Metric ........................ 67 Figure 20...caveat to encryption strength is that what may be strong presently may not always be strong; the Data Encryption Standard ( DES ) was once considered

Shapes of strong shock fronts in an inhomogeneous solar wind

NASA Technical Reports Server (NTRS)

Heinemann, M. A.; Siscoe, G. L.

1974-01-01

The shapes expected for solar-flare-produced strong shock fronts in the solar wind have been calculated, large-scale variations in the ambient medium being taken into account. It has been shown that for reasonable ambient solar wind conditions the mean and the standard deviation of the east-west shock normal angle are in agreement with experimental observations including shocks of all strengths. The results further suggest that near a high-speed stream it is difficult to distinguish between corotating shocks and flare-associated shocks on the basis of the shock normal alone. Although the calculated shapes are outside the range of validity of the linear approximation, these results indicate that the variations in the ambient solar wind may account for large deviations of shock normals from the radial direction.

Relations between productivity, climate, and normalized difference vegetation index in the central Great Plains

NASA Astrophysics Data System (ADS)

Wang, Jue

Understanding the influences of climate on productivity remains a major challenge in landscape ecology. Satellite remote sensing of normalized difference vegetation index (NDVI) provides a useful tool to study landscape patterns, based on generalization of local measurements, and to examine relations between climate and variation in productivity. This dissertation examines temporal and spatial relations between NDVI, productivity, and climatic factors over the course of nine years in the central Great Plains. Two general findings emerge: (1) integrated NDVI is a reliable measure of production, as validated with ground-based productivity measurements; and (2) precipitation is the primary factor that determines spatial and temporal patterns of NDVI. NDVI, integrated over appropriate time intervals, is strongly correlated with ground productivity measurements in forests, grasslands, and croplands. Most tree productivity measurements (tree ring size, tree diameter growth, and seed production) are strongly correlated with NDVI integrated for a period during the early growing season; foliage production is most strongly correlated with NDVI integrated over the entire growing season; and tree height growth corresponds with NDVI integrate during the previous growing season. Similarly, productivity measurements for herbaceous plants (grassland biomass and crop yield) are strongly correlated with NDVI. Within the growing season, the temporal pattern of grassland biomass production covaries with NDVI, with a four-week lag time. Across years, grassland biomass production covaries with NDVI integrated from part to all of the current growing season. Corn and wheat yield are most strongly related to NDVI integrated from late June to early August and from late April to mid-May, respectively. Precipitation strongly influences both temporal and spatial patterns of NDVI, while temperature influences NDVI only during the early and late growing season. In terms of temporal patterns, NDVI integrated over the growing season is strongly correlated with precipitation received during the current growing season plus the seven preceding months (fifteen month period); NDVI within the growing season responds to changes in precipitation with a four to eight week lag time; and major precipitation events lead to changes in NDVI with a two to four week lag time. Temperature has a positive correlation with NDVI during the early and late growing season, and a weak negative correlation during the middle of the growing season. In terms of spatial patterns, average precipitation is a strong predictor of the major east-west gradient of NDVI. Deviation from average precipitation explains most of the year-to-year variation in spatial patterns. NDVI and precipitation deviations from average covary (both positive or both negative) for 60--95% of the total land area in Kansas. Minimum and average temperatures are positively correlated with NDVI, but temperature deviation from average is generally not correlated with NDVI deviation from average. The strong relationships between NDVI and productivity, and between precipitation and NDVI, along with detailed analysis of the temporal and spatial patterns for our study region, provides the basis for prediction of productivity at landscape scales under different climate regimes.

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

Mohapi, N.; Hees, A.; Larena, J., E-mail: n.mohapi@gmail.com, E-mail: a.hees@ru.ac.za, E-mail: j.larena@ru.ac.za

The Einstein Equivalence Principle is a fundamental principle of the theory of General Relativity. While this principle has been thoroughly tested with standard matter, the question of its validity in the Dark sector remains open. In this paper, we consider a general tensor-scalar theory that allows to test the equivalence principle in the Dark sector by introducing two different conformal couplings to standard matter and to Dark matter. We constrain these couplings by considering galactic observations of strong lensing and of velocity dispersion. Our analysis shows that, in the case of a violation of the Einstein Equivalence Principle, data favourmore » violations through coupling strengths that are of opposite signs for ordinary and Dark matter. At the same time, our analysis does not show any significant deviations from General Relativity.« less

Stock markets and criticality in the current economic crisis

NASA Astrophysics Data System (ADS)

da Silva, Roberto; Zembrzuski, Marcelo; Correa, Fabio C.; Lamb, Luis C.

2010-12-01

We show that the current economic crisis has led the market to exhibit a non-critical behavior. We do so by analyzing the quantitative parameters of time series from the main assets of the Brazilian Stock Market BOVESPA. By monitoring global persistence we show a deviation of power law behavior during the crisis in a strong analogy with spin systems (from where this concept was originally conceived). Such behavior is corroborated by an emergent heavy tail of absolute return distribution and also by the magnitude autocorrelation exponent. Comparisons with universal exponents obtained in the international stock markets are also performed. This suggests how a thorough analysis of suitable exponents can bring a possible way of forecasting market crises characterized by non-criticality.

Single-Station Sigma for the Iranian Strong Motion Stations

NASA Astrophysics Data System (ADS)

Zafarani, H.; Soghrat, M. R.

2017-11-01

In development of ground motion prediction equations (GMPEs), the residuals are assumed to have a log-normal distribution with a zero mean and a standard deviation, designated as sigma. Sigma has significant effect on evaluation of seismic hazard for designing important infrastructures such as nuclear power plants and dams. Both aleatory and epistemic uncertainties are involved in the sigma parameter. However, ground-motion observations over long time periods are not available at specific sites and the GMPEs have been derived using observed data from multiple sites for a small number of well-recorded earthquakes. Therefore, sigma is dominantly related to the statistics of the spatial variability of ground motion instead of temporal variability at a single point (ergodic assumption). The main purpose of this study is to reduce the variability of the residuals so as to handle it as epistemic uncertainty. In this regard, it is tried to partially apply the non-ergodic assumption by removing repeatable site effects from total variability of six GMPEs driven from the local, Europe-Middle East and worldwide data. For this purpose, we used 1837 acceleration time histories from 374 shallow earthquakes with moment magnitudes ranging from M w 4.0 to 7.3 recorded at 370 stations with at least two recordings per station. According to estimated single-station sigma for the Iranian strong motion stations, the ratio of event-corrected single-station standard deviation ( Φ ss) to within-event standard deviation ( Φ) is about 0.75. In other words, removing the ergodic assumption on site response resulted in 25% reduction of the within-event standard deviation that reduced the total standard deviation by about 15%.

Identity physics experiment on internal transport barriers in JT-60U and JET

NASA Astrophysics Data System (ADS)

de Vries, P. C.; Sakamoto, Y.; Litaudon, X.; Beurskens, M. N. A.; Brix, M.; Crombé, K.; Fujita, T.; Giroud, C.; Hawkes, N. C.; Hayashi, N.; Joffrin, E.; Mantica, P.; Matsunaga, G.; Oyama, N.; Parail, V.; Salmi, A.; Shinohara, K.; Strintzi, D.; Suzuki, T.; Takechi, M.; Takenaga, H.; Tala, T.; Tsalas, M.; Urano, H.; Voitsekhovitch, I.; Yoshida, M.; EFDA contributors, JET; JT-60 Team

2009-12-01

A series of experiments have been carried out in 2008 at JT-60U and JET to find common characteristics and explain differences between internal transport barriers (ITBs). The identity experiments succeeded in matching the profiles of most dimensionless parameters at the time ITBs were triggered. Thereafter the q-profile development deviated due to differences in non-inductive current density profile, affecting the ITB. Furthermore, the ITBs in JET were more strongly influenced by the H-mode pedestal or edge localized modes. It was found to be difficult to match the plasma rotation characteristics in both devices. However, the wide range of Mach numbers obtained in these experiments shows that the rotation has little effect on the triggering of ITBs in plasmas with reversed magnetic shear. On the other hand the toroidal rotation and more specifically the rotational shear had an impact on the subsequent growth and allowed the formation of strong ITBs.

Quasilinear quantum magnetoresistance in pressure-induced nonsymmorphic superconductor chromium arsenide

NASA Astrophysics Data System (ADS)

Niu, Q.; Yu, W. C.; Yip, K. Y.; Lim, Z. L.; Kotegawa, H.; Matsuoka, E.; Sugawara, H.; Tou, H.; Yanase, Y.; Goh, Swee K.

2017-06-01

In conventional metals, modification of electron trajectories under magnetic field gives rise to a magnetoresistance that varies quadratically at low field, followed by a saturation at high field for closed orbits on the Fermi surface. Deviations from the conventional behaviour, for example, the observation of a linear magnetoresistance, or a non-saturating magnetoresistance, have been attributed to exotic electron scattering mechanisms. Recently, linear magnetoresistance has been observed in many Dirac materials, in which the electron-electron correlation is relatively weak. The strongly correlated helimagnet CrAs undergoes a quantum phase transition to a nonmagnetic superconductor under pressure. Here we observe, near the magnetic instability, a large and non-saturating quasilinear magnetoresistance from the upper critical field to 14 T at low temperatures. We show that the quasilinear magnetoresistance may arise from an intricate interplay between a nontrivial band crossing protected by nonsymmorphic crystal symmetry and strong magnetic fluctuations.

Magnetic field distribution in superconducting composites as revealed by ESR-probe and magnetization

NASA Astrophysics Data System (ADS)

Davidov, D.; Bontemps, N.; Golosovsky, M.; Waysand, G.

1998-03-01

The distribution of a static magnetic field in superconductor-insulator composites consisting of BSCCO (YBCO) powder in paraffin wax is studied by ESR bulk probing and magnetization. The average field and field variance in the non-superconducting host are measured as function of temperature and volume fraction of superconductor. We develop a model of the field distribution in dilute magnetic and superconducting composites that relates the field inhomogeneity to magnetization and particle shape. We find that this model satisfactorily describes field distribution in our superconducting composites in the regime of strong flux pinning, i.e. below irreversibility line. We find deviations from the model above the irreversibility line and attribute this to flux motion. We show that the field distribution in superconducting composites is determined not only by magnetization and particle shape, but is strongly affected by the flux profile within the superconducting particles.

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

Chu, S.; Wang, K.; Layton, E.

In this paper we accomplish three goals. First, we present new nonperturbative results of complex quasi-energies (shifts and widths) for several low-lying excited states of atomic H in strong fields, using the {ital L}{sup 2} non-Hermitian Floquet matrix technique. Second, we present a new nonperturbative {ital L}{sup 2} technique for the treatment of ac Stark shifts of arbitrary excited states. We found that all the Rydberg states in weak fields are upshifted and closely follow the quadratic field dependence described by the ponderomotive potential {ital e}{sup 2}{ital F}{sup 2}/4{ital mgw}{sup 2}. Large deviation from the ponderomotive shift and intricate level-shiftmore » behaviors, however, occur in strong fields. Finally, we present a classical nonperturbative treatment of the electronic motion in intense laser fields. We show that the spectral analysis of classical trajectories can provide detailed insights regarding the mechanisms responsible for the multiple-harmonic generation recently observed in high-intensity experiments.« less

Testing general relativity using gravitational wave signals from the inspiral, merger and ringdown of binary black holes

NASA Astrophysics Data System (ADS)

Ghosh, Abhirup; Johnson-McDaniel, Nathan K.; Ghosh, Archisman; Kant Mishra, Chandra; Ajith, Parameswaran; Del Pozzo, Walter; Berry, Christopher P. L.; Nielsen, Alex B.; London, Lionel

2018-01-01

Advanced LIGO’s recent observations of gravitational waves (GWs) from merging binary black holes have opened up a unique laboratory to test general relativity (GR) in the highly relativistic regime. One of the tests used to establish the consistency of the first LIGO event with a binary black hole merger predicted by GR was the inspiral-merger-ringdown consistency test. This involves inferring the mass and spin of the remnant black hole from the inspiral (low-frequency) part of the observed signal and checking for the consistency of the inferred parameters with the same estimated from the post-inspiral (high-frequency) part of the signal. Based on the observed rate of binary black hole mergers, we expect the advanced GW observatories to observe hundreds of binary black hole mergers every year when operating at their design sensitivities, most of them with modest signal to noise ratios (SNRs). Anticipating such observations, this paper shows how constraints from a large number of events with modest SNRs can be combined to produce strong constraints on deviations from GR. Using kludge modified GR waveforms, we demonstrate how this test could identify certain types of deviations from GR if such deviations are present in the signal waveforms. We also study the robustness of this test against reasonable variations of a variety of different analysis parameters.

Concretionary manganese-iron oxides in streams and their usefulness as a sample medium for geochemical prospecting

USGS Publications Warehouse

Nowlan, G.A.

1976-01-01

Correlation studies of 400 samples of sieved stream sediments and 325 samples of fluvial, concretionary Mn-Fe oxides from Maine resulted in the separation of elements into the following categories: (1) elements not scavenged by Mn-Fe oxides - B, Cr, K, Mg, Rb, Sc, Ti, V, and Zr; (2) elements probably not scavenged by Mn-Fe oxides - Ag, Be, Ca, Ga, La, Sb, and Y; (3) elements scavenged weakly by Mn-Fe oxides - Cu, Mo, Pb, and Sr; (4) elements scavenged strongly by Mn oxides - Ba, Cd, Co, Ni, Tl, and Zn; and (5) elements scavenged strongly by Fe oxides - As and In. Studies of the scavenged elements showed that the deviation from the mean is characteristically greater in oxide samples as compared to sieved sediments from the same locality. However, a significant increase in contrast between anomalous and background localities, when oxides are the sample medium, more than offsets the disadvantage of data scatter. The use of oxides as a sampling medium clearly and significantly accentuates anomalous localities. In general, non-ratioed data on oxides give very nearly the same results as data consisting of scavenged elements ratioed to Mn and Fe. However, ratioed data expand the geographic area of specific anomalies. Cd and Zn consistently show strong correlations with concretionary Mn-Fe oxides, but their concentrations in the oxides do not generally show as much contrast between anomalous and background localities as do Cu, Mo, and Pb. These latter elements are strongly scavenged where rocks are mineralized. ?? 1976.

Trajectory Control of Small Rotating Projectiles by Laser Sparks

NASA Astrophysics Data System (ADS)

Starikovskiy, Andrey; Limbach, Christopher; Miles, Richard

2015-09-01

The possibility of controlling the trajectory of the supersonic motion of a rotating axisymmetric projectile using a remotely generated laser spark was investigated. The dynamic images of the interaction of thermal inhomogeneity created by the laser spark with the bow shock in front of the projectile were obtained. The criterion for a strong shock wave interaction with the thermal inhomogeneity at different angles of a shock wave was derived. Significant changes in the configuration of the bow shock wave and changes in the pressure distribution over the surface of the rotating projectile can appear for laser spark temperature of T' = 2500-3000 K. The experiment showed that strong interaction takes place for both plane and oblique shock waves. The measurement of the velocity of the precession of the rotating projectile axis from the initial position in time showed that the angle of attack of the projectile deviates with a typical time of perturbation propagation along the projectile's surface. Thus the laser spark can change the trajectory of the rotating projectile, moving at supersonic speed, through the creation of thermal heterogeneity in front of it.

Directional learning and the provisioning of public goods.

PubMed

Nax, Heinrich H; Perc, Matjaž

2015-01-26

We consider an environment where players are involved in a public goods game and must decide repeatedly whether to make an individual contribution or not. However, players lack strategically relevant information about the game and about the other players in the population. The resulting behavior of players is completely uncoupled from such information, and the individual strategy adjustment dynamics are driven only by reinforcement feedbacks from each player's own past. We show that the resulting "directional learning" is sufficient to explain cooperative deviations away from the Nash equilibrium. We introduce the concept of k-strong equilibria, which nest both the Nash equilibrium and the Aumann-strong equilibrium as two special cases, and we show that, together with the parameters of the learning model, the maximal k-strength of equilibrium determines the stationary distribution. The provisioning of public goods can be secured even under adverse conditions, as long as players are sufficiently responsive to the changes in their own payoffs and adjust their actions accordingly. Substantial levels of public cooperation can thus be explained without arguments involving selflessness or social preferences, solely on the basis of uncoordinated directional (mis)learning.

Intertidal nematode communities in the Mekong estuaries of Vietnam and their potential for biomonitoring.

PubMed

Quang, Ngo Xuan; Chau, Nguyen Ngoc; Smol, Nic; Prozorova, Larisa; Vanreusel, Ann

2016-02-01

Nematode communities in eight Mekong estuaries were investigated during the dry season. The aim of the study was to identify the structure and the diversity of the communities in relation to the main environmental characteristics. In each estuary, three to four intertidal sampling stations were identified at regular distances from the mouth to up to 45 km land inward. The nematode communities showed a strong correlation with sediment composition and to a lesser degree with chlorophyll a concentrations. Multivariate analysis resulted in the identification of four types of communities. We identified two types of Desmodora communities in the sandy mouth stations and two types of Parodontophora communities in the silty sand stations. One of the silt associated communities showed a preference for higher chlorophyll a concentrations, resulting in higher densities and higher diversity, mainly of monhysterid species. Because of the strong association between community structure and sediment composition, nematodes are a meaningful tool for monitoring changes in their environment. In case their community deviates from what is expected based on sediment, it may serve as an early warning for disturbance.

High Useful Yield and Isotopic Analysis of Uranium by Resonance Ionization Mass Spectrometry

DOE PAGES

Savina, Michael R.; Isselhardt, Brett H.; Kucher, Andrew; ...

2017-05-09

Useful yields from resonance ionization mass spectrometry can be extremely high compared to other mass spectrometry techniques, but uranium analysis shows strong matrix effects arising from the tendency of uranium to form strongly bound oxide molecules that do not dissociate appreciably on energetic ion bombardment. Here, we demonstrate a useful yield of 24% for metallic uranium. Modeling the laser ionization and ion transmission processes shows that the high useful yield is attributable to a high ion fraction achieved by resonance ionization. We quantify the reduction of uranium oxide surface layers by Ar + and Ga + sputtering. The useful yieldmore » for uranium atoms from a uranium dioxide matrix is 0.4% and rises to 2% when the surface is in sputter equilibrium with the ion beam. The lower useful yield from the oxide is almost entirely due to uranium oxide molecules reducing the neutral atom content of the sputtered flux. We also demonstrate rapid isotopic analysis of solid uranium oxide at a precision of <0.5% relative standard deviation using relatively broadband lasers to mitigate spectroscopic fractionation.« less

High Useful Yield and Isotopic Analysis of Uranium by Resonance Ionization Mass Spectrometry

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

Savina, Michael R.; Isselhardt, Brett H.; Kucher, Andrew

Useful yields from resonance ionization mass spectrometry can be extremely high compared to other mass spectrometry techniques, but uranium analysis shows strong matrix effects arising from the tendency of uranium to form strongly bound oxide molecules that do not dissociate appreciably on energetic ion bombardment. Here, we demonstrate a useful yield of 24% for metallic uranium. Modeling the laser ionization and ion transmission processes shows that the high useful yield is attributable to a high ion fraction achieved by resonance ionization. We quantify the reduction of uranium oxide surface layers by Ar + and Ga + sputtering. The useful yieldmore » for uranium atoms from a uranium dioxide matrix is 0.4% and rises to 2% when the surface is in sputter equilibrium with the ion beam. The lower useful yield from the oxide is almost entirely due to uranium oxide molecules reducing the neutral atom content of the sputtered flux. We also demonstrate rapid isotopic analysis of solid uranium oxide at a precision of <0.5% relative standard deviation using relatively broadband lasers to mitigate spectroscopic fractionation.« less

Experimental study of the dynamics of a ruby laser pumped by a CW argon-ion laser

NASA Technical Reports Server (NTRS)

Afzal, R. S.; Lin, W. P.; Lawandy, N. M.

1989-01-01

A study of the dynamics of a ruby laser pumped by a CW argon-ion laser is presented. The ruby laser is predominantly stable but has two accessible unstable states. One state exhibits chaotic output, while the other results in regular self-pulsing. The conditions needed for instability are discussed and homodyne spectra and temporal maps of the phase-space attractors are obtained. In addition, a numerical simulation of nonlinear beam propagation in ruby is presented that shows that strong deviations from plane-wave behavior exist, and that transverse effects must be incorporated into theoretical models of the instability.

Bubbles Are Departures from Equilibrium Housing Markets: Evidence from Singapore and Taiwan

PubMed Central

Chou, Chung-I; Li, Sai-Ping; Tee, Shang You; Cheong, Siew Ann

2016-01-01

The housing prices in many Asian cities have grown rapidly since mid-2000s, leading to many reports of bubbles. However, such reports remain controversial as there is no widely accepted definition for a housing bubble. Previous studies have focused on indices, or assumed that home prices are lognomally distributed. Recently, Ohnishi et al. showed that the tail-end of the distribution of (Japan/Tokyo) becomes fatter during years where bubbles are suspected, but stop short of using this feature as a rigorous definition of a housing bubble. In this study, we look at housing transactions for Singapore (1995 to 2014) and Taiwan (2012 to 2014), and found strong evidence that the equilibrium home price distribution is a decaying exponential crossing over to a power law, after accounting for different housing types. We found positive deviations from the equilibrium distributions in Singapore condominiums and Zhu Zhai Da Lou in the Greater Taipei Area. These positive deviations are dragon kings, which thus provide us with an unambiguous and quantitative definition of housing bubbles. Also, the spatial-temporal dynamics show that bubble in Singapore is driven by price pulses in two investment districts. This finding provides a valuable insight for policymakers on implementation and evaluation of cooling measures. PMID:27812187

Sulfate Assimilation Mediates Tellurite Reduction and Toxicity in Saccharomyces cerevisiae▿†

PubMed Central

Ottosson, Lars-Göran; Logg, Katarina; Ibstedt, Sebastian; Sunnerhagen, Per; Käll, Mikael; Blomberg, Anders; Warringer, Jonas

2010-01-01

Despite a century of research and increasing environmental and human health concerns, the mechanistic basis of the toxicity of derivatives of the metalloid tellurium, Te, in particular the oxyanion tellurite, Te(IV), remains unsolved. Here, we provide an unbiased view of the mechanisms of tellurium metabolism in the yeast Saccharomyces cerevisiae by measuring deviations in Te-related traits of a complete collection of gene knockout mutants. Reduction of Te(IV) and intracellular accumulation as metallic tellurium strongly correlated with loss of cellular fitness, suggesting that Te(IV) reduction and toxicity are causally linked. The sulfate assimilation pathway upstream of Met17, in particular, the sulfite reductase and its cofactor siroheme, was shown to be central to tellurite toxicity and its reduction to elemental tellurium. Gene knockout mutants with altered Te(IV) tolerance also showed a similar deviation in tolerance to both selenite and, interestingly, selenomethionine, suggesting that the toxicity of these agents stems from a common mechanism. We also show that Te(IV) reduction and toxicity in yeast is partially mediated via a mitochondrial respiratory mechanism that does not encompass the generation of substantial oxidative stress. The results reported here represent a robust base from which to attack the mechanistic details of Te(IV) toxicity and reduction in a eukaryotic organism. PMID:20675578

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

Mun, Eundeok; Bud'ko, Sergey L.; Canfield, Paul C.

We present the magnetic field dependencies of transport properties for RPtBi ( R = Gd, Dy, Tm, and Lu) half-Heusler compounds. Temperature- and field-dependent resistivity measurements of high-quality RPtBi single crystals reveal an unusually large, nonsaturating magnetoresistance (MR) up to 300 K under a moderate magnetic field of H = 140 kOe. At 300 K, the large MR effect decreases as the rare earth is traversed from Gd to Lu and the magnetic field dependence of MR shows a deviation from the conventional H2 behavior. The Hall coefficient ( RH) for R = Gd indicates a sign change around 120more » K, whereas RH curves for R = Dy, Tm, and Lu remain positive for all measured temperatures. At 300 K, the Hall resistivity reveals a deviation from the linear field dependence for all compounds. Thermoelectric power measurements on this family show strong temperature and magnetic field dependencies which are consistent with resistivity measurements. A highly enhanced thermoelectric power under applied magnetic field is observed as high as ~100 μV/K at 140 kOe. Furthermore, analysis of the transport data in this series reveals that the rare-earth-based half-Heusler compounds provide opportunities to tune MR effect through lanthanide contraction and to elucidate the mechanism of nontrivial MR.« less

Effects of local extinction on mixture fraction and scalar dissipation statistics in turbulent nonpremixed flames

NASA Astrophysics Data System (ADS)

Attili, Antonio; Bisetti, Fabrizio

2015-11-01

Passive scalar and scalar dissipation statistics are investigated in a set of flames achieving a Taylor's scale Reynolds number in the range 100 <=Reλ <= 150 [Attili et al. Comb. Flame 161, 2014; Attili et al. Proc. Comb. Inst. 35, 2015]. The three flames simulated show an increasing level of extinction due to the decrease of the Damköhler number. In the case of negligible extinction, the non-dimensional scalar dissipation is expected to be the same in the three cases. In the present case, the deviations from the aforementioned self-similarity manifests itself as a decrease of the non-dimensional scalar dissipation for increasing level of local extinction, in agreement with recent experiments [Karpetis and Barlow Proc. Comb. Inst. 30, 2005; Sutton and Driscoll Combust. Flame 160, 2013 ]. This is caused by the decrease of molecular diffusion due to the lower temperature in the low Damköhler number cases. Probability density functions of the scalar dissipation χ show rather strong deviations from the log-normal distribution. The left tail of the pdf scales as χ 1 / 2 while the right tail scales as e-cχα, in agreement with results for incompressible turbulence [Schumacher et al. J. Fluid Mech. 531, 2005].

Bubbles Are Departures from Equilibrium Housing Markets: Evidence from Singapore and Taiwan.

PubMed

Tay, Darrell Jiajie; Chou, Chung-I; Li, Sai-Ping; Tee, Shang You; Cheong, Siew Ann

2016-01-01

The housing prices in many Asian cities have grown rapidly since mid-2000s, leading to many reports of bubbles. However, such reports remain controversial as there is no widely accepted definition for a housing bubble. Previous studies have focused on indices, or assumed that home prices are lognomally distributed. Recently, Ohnishi et al. showed that the tail-end of the distribution of (Japan/Tokyo) becomes fatter during years where bubbles are suspected, but stop short of using this feature as a rigorous definition of a housing bubble. In this study, we look at housing transactions for Singapore (1995 to 2014) and Taiwan (2012 to 2014), and found strong evidence that the equilibrium home price distribution is a decaying exponential crossing over to a power law, after accounting for different housing types. We found positive deviations from the equilibrium distributions in Singapore condominiums and Zhu Zhai Da Lou in the Greater Taipei Area. These positive deviations are dragon kings, which thus provide us with an unambiguous and quantitative definition of housing bubbles. Also, the spatial-temporal dynamics show that bubble in Singapore is driven by price pulses in two investment districts. This finding provides a valuable insight for policymakers on implementation and evaluation of cooling measures.

Combined Characterization of the Time Response of Impression Materials via Traditional and FTIR Measurements

PubMed Central

Derchi, Giacomo; Manca, Enrico; Shayganpour, Amirreza; Barone, Antonio; Diaspro, Alberto; Salerno, Marco

2015-01-01

We investigated the temporal response of four dental impression materials, namely three siloxanes (Imprint 4, Flexitime, Aquasil) and one polyether (Impregum). The null hypothesis was that the nominal working times are confirmed by instrumental laboratory tests. We also aimed to identify alternative techniques with strong physical-chemical background for the assessment of temporal response. Traditional characterization was carried out by shark fin test device and durometer at both ambient and body temperature. Additionally, Fourier-transform infrared spectroscopy was performed at room temperature. From shark fin height and Shore hardness versus time the working time and the setting time of the materials were evaluated, respectively. These were in reasonable agreement with the nominal values, except for Impregum, which showed longer working time. Spectroscopy confirmed the different character of the two types of materials, and provided for Imprint 4 and Aquasil an independent evaluation of both evolution times, consistent with the results of the other techniques. Shark fin test and durometer measurements showed deviations in setting time, low sensitivity to temperature for Flexitime, and longer working time at higher temperature for Impregum. Deviations of working time appear in operating conditions from what specified by the manufacturers. Fourier-transform infrared spectroscopy can provide insight in the correlation between material properties and their composition and structure.

Estimating the contribution of strong daily export events to total pollutant export from the United States in summer

NASA Astrophysics Data System (ADS)

Fang, Yuanyuan; Fiore, Arlene M.; Horowitz, Larry W.; Gnanadesikan, Anand; Levy, Hiram; Hu, Yongtao; Russell, Armistead G.

2009-12-01

While the export of pollutants from the United States exhibits notable variability from day to day and is often considered to be "episodic," the contribution of strong daily export events to total export has not been quantified. We use carbon monoxide (CO) as a tracer of anthropogenic pollutants in the Model of OZone And Related Tracers (MOZART) to estimate this contribution. We first identify the major export pathway from the United States to be through the northeast boundary (24-48°N along 67.5°W and 80-67.5°W along 48°N), and then analyze 15 summers of daily CO export fluxes through this boundary. These daily CO export fluxes have a nearly Gaussian distribution with a mean of 1100 Gg CO day-1 and a standard deviation of 490 Gg CO day-1. To focus on the synoptic variability, we define a "synoptic background" export flux equal to the 15 day moving average export flux and classify strong export days according to their fluxes relative to this background. As expected from Gaussian statistics, 16% of summer days are "strong export days," classified as those days when the CO export flux exceeds the synoptic background by one standard deviation or more. Strong export days contributes 25% to the total export, a value determined by the relative standard deviation of the CO flux distribution. Regressing the anomalies of the CO export flux through the northeast U.S. boundary relative to the synoptic background on the daily anomalies in the surface pressure field (also relative to a 15 day running mean) suggests that strong daily export fluxes are correlated with passages of midlatitude cyclones over the Gulf of Saint Lawrence. The associated cyclonic circulation and Warm Conveyor Belts (WCBs) that lift surface pollutants over the northeastern United States have been shown previously to be associated with long-range transport events. Comparison with observations from the 2004 INTEX-NA field campaign confirms that our model captures the observed enhancements in CO outflow and resolves the processes associated with cyclone passages on strong export days. "Moderate export days," defined as days when the CO flux through the northeast boundary exceeds the 15 day running mean by less than one standard deviation, represent an additional 34% of summer days and 40% of total export. These days are also associated with migratory midlatitude cyclones. The remaining 35% of total export occurs on "weak export days" (50% of summer days) when high pressure anomalies occur over the Gulf of Saint Lawrence. Our findings for summer also apply to spring, when the U.S. pollutant export is typically strongest, with similar contributions to total export and associated meteorology on strong, moderate and weak export days. Although cyclone passages are the primary driver for strong daily export events, export during days without cyclone passages also makes a considerable contribution to the total export and thereby to the global pollutant budget.

Comparison of Profile Total Ozone from SBUV (v8.6) with GOME-Type and Ground-Based Total Ozone for a 16-Year Period (1996 to 2011)

NASA Technical Reports Server (NTRS)

Chiou, E. W.; Bhartia, P. K.; McPeters, R. D.; Loyola, D. G.; Coldewey-Egbers, M.; Fioletov, V. E.; Van Roozendael, M.; Spurr, R.; Lerot, C.; Frith, S. M.

2014-01-01

This paper describes the comparison of the variability of total column ozone inferred from the three independent multi-year data records, namely, (i) Solar Backscatter Ultraviolet Instrument (SBUV) v8.6 profile total ozone, (ii) GTO (GOME-type total ozone), and (iii) ground-based total ozone data records covering the 16-year overlap period (March 1996 through June 2011). Analyses are conducted based on area-weighted zonal means for 0-30degS, 0-30degN, 50-30degS, and 30-60degN. It has been found that, on average, the differences in monthly zonal mean total ozone vary between -0.3 and 0.8% and are well within 1 %. For GTO minus SBUV, the standard deviations and ranges (maximum minus minimum) of the differences regarding monthly zonal mean total ozone vary between 0.6-0.7% and 2.8-3.8% respectively, depending on the latitude band. The corresponding standard deviations and ranges regarding the differences in monthly zonal mean anomalies show values between 0.4-0.6% and 2.2-3.5 %. The standard deviations and ranges of the differences ground-based minus SBUV regarding both monthly zonal means and anomalies are larger by a factor of 1.4-2.9 in comparison to GTO minus SBUV. The ground-based zonal means demonstrate larger scattering of monthly data compared to satellite-based records. The differences in the scattering are significantly reduced if seasonal zonal averages are analyzed. The trends of the differences GTO minus SBUV and ground-based minus SBUV are found to vary between -0.04 and 0.1%/yr (-0.1 and 0.3DU/yr). These negligibly small trends have provided strong evidence that there are no significant time-dependent differences among these multiyear total ozone data records. Analyses of the annual deviations from pre-1980 level indicate that, for the 15-year period of 1996 to 2010, all three data records show a gradual increase at 30-60degN from -5% in 1996 to -2% in 2010. In contrast, at 50-30degS and 30degS- 30degN there has been a leveling off in the 15 years after 1996. The deviations inferred from GTO and SBUV show agreement within 1 %, but a slight increase has been found in the differences during the period 1996-2010.

Detailed Investigation of Self-Similarity of Strong Shock Reflection Phenomena

NASA Astrophysics Data System (ADS)

Kobayashi, Susumu; Adachi, Takashi

2012-04-01

This paper experimentally investigates the validity of self-similarity of strong shock reflection phenomena in a shock tube. The models used for the shock-tube experiment are ordinary wedges with various reflecting wedge angles. The triple-point trajectory is approximately a straight line through the wedge apex for each reflecting wedge. However, a detailed measurement of the angle made by the incident and reflected shocks shows that the wave angle varies as the incident shock proceeds. This means that the shock reflection configuration deviates from self-similarity. The most remarkable phenomenon is the dynamic transition from regular to Mach reflection during shock propagation, where the validity of self-similarity breaks down. The flow-field behind the Mach stem is subsonic with respect to the triple point, so the condition on the solid boundary can catch up with the triple point and affect the flow around it. We also explain why the discrepancy between theory and experiment has gone unnoticed for strong shock waves and demonstrate that it is due to the transport properties of the fluid, such as the viscosity.

First-Principles Momentum Dependent Local Ansatz Approach to the Momentum Distribution Function in Iron-Group Transition Metals

NASA Astrophysics Data System (ADS)

Kakehashi, Yoshiro; Chandra, Sumal

2017-03-01

The momentum distribution function (MDF) bands of iron-group transition metals from Sc to Cu have been investigated on the basis of the first-principles momentum dependent local ansatz wavefunction method. It is found that the MDF for d electrons show a strong momentum dependence and a large deviation from the Fermi-Dirac distribution function along high-symmetry lines of the first Brillouin zone, while the sp electrons behave as independent electrons. In particular, the deviation in bcc Fe (fcc Ni) is shown to be enhanced by the narrow eg (t2g) bands with flat dispersion in the vicinity of the Fermi level. Mass enhancement factors (MEF) calculated from the jump on the Fermi surface are also shown to be momentum dependent. Large mass enhancements of Mn and Fe are found to be caused by spin fluctuations due to d electrons, while that for Ni is mainly caused by charge fluctuations. Calculated MEF are consistent with electronic specific heat data as well as recent angle resolved photoemission spectroscopy data.

PARALLAX AND ORBITAL EFFECTS IN ASTROMETRIC MICROLENSING WITH BINARY SOURCES

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

Nucita, A. A.; Paolis, F. De; Ingrosso, G.

2016-06-01

In gravitational microlensing, binary systems may act as lenses or sources. Identifying lens binarity is generally easy, in particular in events characterized by caustic crossing since the resulting light curve exhibits strong deviations from a smooth single-lensing light curve. In contrast, light curves with minor deviations from a Paczyński behavior do not allow one to identify the source binarity. A consequence of gravitational microlensing is the shift of the position of the multiple image centroid with respect to the source star location — the so-called astrometric microlensing signal. When the astrometric signal is considered, the presence of a binary sourcemore » manifests with a path that largely differs from that expected for single source events. Here, we investigate the astrometric signatures of binary sources taking into account their orbital motion and the parallax effect due to the Earth’s motion, which turn out not to be negligible in most cases. We also show that considering the above-mentioned effects is important in the analysis of astrometric data in order to correctly estimate the lens-event parameters.« less

Evaluation of the navigation performance of shipboard-VTOL-landing guidance systems

NASA Technical Reports Server (NTRS)

Mcgee, L. A.; Paulk, C. H., Jr.; Steck, S. A.; Schmidt, S. F.; Merz, A. W.

1979-01-01

The objective of this study was to explore the performance of a VTOL aircraft landing approach navigation system that receives data (1) from either a microwave scanning beam (MSB) or a radar-transponder (R-T) landing guidance system, and (2) information data-linked from an aviation facility ship. State-of-the-art low-cost-aided inertial techniques and variable gain filters were used in the assumed navigation system. Compensation for ship motion was accomplished by a landing pad deviation vector concept that is a measure of the landing pad's deviation from its calm sea location. The results show that the landing guidance concepts were successful in meeting all of the current Navy navigation error specifications, provided that vector magnitude of the allowable error, rather than the error in each axis, is a permissible interpretation of acceptable performance. The success of these concepts, however, is strongly dependent on the distance measuring equipment bias. In addition, the 'best possible' closed-loop tracking performance achievable with the assumed point-mass VTOL aircraft guidance concept is demonstrated.

Sensitivity of super-efficient data envelopment analysis results to individual decision-making units: an example of surgical workload by specialty.

PubMed

Dexter, Franklin; O'Neill, Liam; Xin, Lei; Ledolter, Johannes

2008-12-01

We use resampling of data to explore the basic statistical properties of super-efficient data envelopment analysis (DEA) when used as a benchmarking tool by the manager of a single decision-making unit. Our focus is the gaps in the outputs (i.e., slacks adjusted for upward bias), as they reveal which outputs can be increased. The numerical experiments show that the estimates of the gaps fail to exhibit asymptotic consistency, a property expected for standard statistical inference. Specifically, increased sample sizes were not always associated with more accurate forecasts of the output gaps. The baseline DEA's gaps equaled the mode of the jackknife and the mode of resampling with/without replacement from any subset of the population; usually, the baseline DEA's gaps also equaled the median. The quartile deviations of gaps were close to zero when few decision-making units were excluded from the sample and the study unit happened to have few other units contributing to its benchmark. The results for the quartile deviations can be explained in terms of the effective combinations of decision-making units that contribute to the DEA solution. The jackknife can provide all the combinations contributing to the quartile deviation and only needs to be performed for those units that are part of the benchmark set. These results show that there is a strong rationale for examining DEA results with a sensitivity analysis that excludes one benchmark hospital at a time. This analysis enhances the quality of decision support using DEA estimates for the potential ofa decision-making unit to grow one or more of its outputs.

Advances in snow cover distributed modelling via ensemble simulations and assimilation of satellite data

NASA Astrophysics Data System (ADS)

Revuelto, J.; Dumont, M.; Tuzet, F.; Vionnet, V.; Lafaysse, M.; Lecourt, G.; Vernay, M.; Morin, S.; Cosme, E.; Six, D.; Rabatel, A.

2017-12-01

Nowadays snowpack models show a good capability in simulating the evolution of snow in mountain areas. However singular deviations of meteorological forcing and shortcomings in the modelling of snow physical processes, when accumulated on time along a snow season, could produce large deviations from real snowpack state. The evaluation of these deviations is usually assessed with on-site observations from automatic weather stations. Nevertheless the location of these stations could strongly influence the results of these evaluations since local topography may have a marked influence on snowpack evolution. Despite the evaluation of snowpack models with automatic weather stations usually reveal good results, there exist a lack of large scale evaluations of simulations results on heterogeneous alpine terrain subjected to local topographic effects.This work firstly presents a complete evaluation of the detailed snowpack model Crocus over an extended mountain area, the Arve upper catchment (western European Alps). This catchment has a wide elevation range with a large area above 2000m a.s.l. and/or glaciated. The evaluation compares results obtained with distributed and semi-distributed simulations (the latter nowadays used on the operational forecasting). Daily observations of the snow covered area from MODIS satellite sensor, seasonal glacier surface mass balance evolution measured in more than 65 locations and the galciers annual equilibrium line altitude from Landsat/Spot/Aster satellites, have been used for model evaluation. Additionally the latest advances in producing ensemble snowpack simulations for assimilating satellite reflectance data over extended areas will be presented. These advances comprises the generation of an ensemble of downscaled high-resolution meteorological forcing from meso-scale meteorological models and the application of a particle filter scheme for assimilating satellite observations. Despite the results are prefatory, they show a good potential improving snowpack forecasting capabilities.

The effect of human immunodeficiency virus type 1 antibody status on military applicant aptitude test scores.

PubMed

Arday, D R; Brundage, J F; Gardner, L I; Goldenbaum, M; Wann, F; Wright, S

1991-06-15

The authors conducted a population-based study to attempt to estimate the effect of human immunodeficiency virus type 1 (HIV-1) seropositivity on Armed Services Vocational Aptitude Battery test scores in otherwise healthy individuals with early HIV-1 infection. The Armed Services Vocational Aptitude Battery is a 10-test written multiple aptitude battery administered to all civilian applicants for military enlistment prior to serologic screening for HIV-1 antibodies. A total of 975,489 induction testing records containing both Armed Services Vocational Aptitude Battery and HIV-1 results from October 1985 through March 1987 were examined. An analysis data set (n = 7,698) was constructed by choosing five controls for each of the 1,283 HIV-1-positive cases, matched on five-digit ZIP code, and a multiple linear regression analysis was performed to control for demographic and other factors that might influence test scores. Years of education was the strongest predictor of test scores, raising an applicant's score on a composite test nearly 0.16 standard deviation per year. The HIV-1-positive effect on the composite score was -0.09 standard deviation (99% confidence interval -0.17 to -0.02). Separate regressions on each component test within the battery showed HIV-1 effects between -0.39 and +0.06 standard deviation. The two Armed Services Vocational Aptitude Battery component tests felt a priori to be the most sensitive to HIV-1-positive status showed the least decrease with seropositivity. Much of the variability in test scores was not predicted by either HIV-1 serostatus or the demographic and other factors included in the model. There appeared to be little evidence of a strong HIV-1 effect.

Preconditioning of Interplanetary Space Due to Transient CME Disturbances

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

Temmer, M.; Reiss, M. A.; Hofmeister, S. J.

Interplanetary space is characteristically structured mainly by high-speed solar wind streams emanating from coronal holes and transient disturbances such as coronal mass ejections (CMEs). While high-speed solar wind streams pose a continuous outflow, CMEs abruptly disrupt the rather steady structure, causing large deviations from the quiet solar wind conditions. For the first time, we give a quantification of the duration of disturbed conditions (preconditioning) for interplanetary space caused by CMEs. To this aim, we investigate the plasma speed component of the solar wind and the impact of in situ detected interplanetary CMEs (ICMEs), compared to different background solar wind modelsmore » (ESWF, WSA, persistence model) for the time range 2011–2015. We quantify in terms of standard error measures the deviations between modeled background solar wind speed and observed solar wind speed. Using the mean absolute error, we obtain an average deviation for quiet solar activity within a range of 75.1–83.1 km s{sup −1}. Compared to this baseline level, periods within the ICME interval showed an increase of 18%–32% above the expected background, and the period of two days after the ICME displayed an increase of 9%–24%. We obtain a total duration of enhanced deviations over about three and up to six days after the ICME start, which is much longer than the average duration of an ICME disturbance itself (∼1.3 days), concluding that interplanetary space needs ∼2–5 days to recover from the impact of ICMEs. The obtained results have strong implications for studying CME propagation behavior and also for space weather forecasting.« less

Porosity of spacer-filled channels in spiral-wound membrane systems: Quantification methods and impact on hydraulic characterization.

PubMed

Siddiqui, A; Lehmann, S; Haaksman, V; Ogier, J; Schellenberg, C; van Loosdrecht, M C M; Kruithof, J C; Vrouwenvelder, J S

2017-08-01

The porosity of spacer-filled feed channels influences the hydrodynamics of spiral-wound membrane systems and impacts the overall performance of the system. Therefore, an exact measurement and a detailed understanding of the impact of the feed channel porosity is required to understand and improve the hydrodynamics of spiral-wound membrane systems applied for desalination and wastewater reuse. The objectives of this study were to assess the accuracy of porosity measurement techniques for feed spacers differing in geometry and thickness and the consequences of using an inaccurate method on hydrodynamic predictions, which may affect permeate production. Six techniques were applied to measure the porosity namely, three volumetric techniques based on spacer strand count together with a cuboidal (SC), cylindrical (VCC) and ellipsoidal volume calculation (VCE) and three independent techniques based on volume displacement (VD), weight and density (WD) and computed tomography (CT) scanning. The CT method was introduced as an alternative for the other five already existing and applied methods in practice. Six feed spacers used for the porosity measurement differed in filament thickness, angle between the filaments and mesh-size. The results of the studies showed differences between the porosities, measured by the six methods. The results of the microscopic techniques SC, VCC and VCE deviated significantly from measurements by VD, WD and CT, which showed similar porosity values for all spacer types. Depending on the maximum deviation of the porosity measurement techniques from -6% to +6%, (i) the linear velocity deviations were -5.6% and +6.4% respectively and (ii) the pressure drop deviations were -31% and +43% respectively, illustrating the importance of an accurate porosity measurement. Because of the accuracy and standard deviation, the VD and WD method should be applied for the porosity determination of spacer-filled channels, while the CT method is recommended for numerical modelling purposes. The porosity has a linear relationship with the flow velocity and a superlinear effect on the pressure drop. Accurate porosity data are essential to evaluate feed spacer performance in spiral-wound membrane systems. Porosity of spacer-filled feed channels has a strong impact on membrane performance and biofouling impact. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Investigation of sequential properties of snoring episodes for obstructive sleep apnoea identification.

PubMed

Cavusoglu, M; Ciloglu, T; Serinagaoglu, Y; Kamasak, M; Erogul, O; Akcam, T

2008-08-01

In this paper, 'snore regularity' is studied in terms of the variations of snoring sound episode durations, separations and average powers in simple snorers and in obstructive sleep apnoea (OSA) patients. The goal was to explore the possibility of distinguishing among simple snorers and OSA patients using only sleep sound recordings of individuals and to ultimately eliminate the need for spending a whole night in the clinic for polysomnographic recording. Sequences that contain snoring episode durations (SED), snoring episode separations (SES) and average snoring episode powers (SEP) were constructed from snoring sound recordings of 30 individuals (18 simple snorers and 12 OSA patients) who were also under polysomnographic recording in Gülhane Military Medical Academy Sleep Studies Laboratory (GMMA-SSL), Ankara, Turkey. Snore regularity is quantified in terms of mean, standard deviation and coefficient of variation values for the SED, SES and SEP sequences. In all three of these sequences, OSA patients' data displayed a higher variation than those of simple snorers. To exclude the effects of slow variations in the base-line of these sequences, new sequences that contain the coefficient of variation of the sample values in a 'short' signal frame, i.e., short time coefficient of variation (STCV) sequences, were defined. The mean, the standard deviation and the coefficient of variation values calculated from the STCV sequences displayed a stronger potential to distinguish among simple snorers and OSA patients than those obtained from the SED, SES and SEP sequences themselves. Spider charts were used to jointly visualize the three parameters, i.e., the mean, the standard deviation and the coefficient of variation values of the SED, SES and SEP sequences, and the corresponding STCV sequences as two-dimensional plots. Our observations showed that the statistical parameters obtained from the SED and SES sequences, and the corresponding STCV sequences, possessed a strong potential to distinguish among simple snorers and OSA patients, both marginally, i.e., when the parameters are examined individually, and jointly. The parameters obtained from the SEP sequences and the corresponding STCV sequences, on the other hand, did not have a strong discrimination capability. However, the joint behaviour of these parameters showed some potential to distinguish among simple snorers and OSA patients.

MetaMQAP: a meta-server for the quality assessment of protein models.

PubMed

Pawlowski, Marcin; Gajda, Michal J; Matlak, Ryszard; Bujnicki, Janusz M

2008-09-29

Computational models of protein structure are usually inaccurate and exhibit significant deviations from the true structure. The utility of models depends on the degree of these deviations. A number of predictive methods have been developed to discriminate between the globally incorrect and approximately correct models. However, only a few methods predict correctness of different parts of computational models. Several Model Quality Assessment Programs (MQAPs) have been developed to detect local inaccuracies in unrefined crystallographic models, but it is not known if they are useful for computational models, which usually exhibit different and much more severe errors. The ability to identify local errors in models was tested for eight MQAPs: VERIFY3D, PROSA, BALA, ANOLEA, PROVE, TUNE, REFINER, PROQRES on 8251 models from the CASP-5 and CASP-6 experiments, by calculating the Spearman's rank correlation coefficients between per-residue scores of these methods and local deviations between C-alpha atoms in the models vs. experimental structures. As a reference, we calculated the value of correlation between the local deviations and trivial features that can be calculated for each residue directly from the models, i.e. solvent accessibility, depth in the structure, and the number of local and non-local neighbours. We found that absolute correlations of scores returned by the MQAPs and local deviations were poor for all methods. In addition, scores of PROQRES and several other MQAPs strongly correlate with 'trivial' features. Therefore, we developed MetaMQAP, a meta-predictor based on a multivariate regression model, which uses scores of the above-mentioned methods, but in which trivial parameters are controlled. MetaMQAP predicts the absolute deviation (in Angströms) of individual C-alpha atoms between the model and the unknown true structure as well as global deviations (expressed as root mean square deviation and GDT_TS scores). Local model accuracy predicted by MetaMQAP shows an impressive correlation coefficient of 0.7 with true deviations from native structures, a significant improvement over all constituent primary MQAP scores. The global MetaMQAP score is correlated with model GDT_TS on the level of 0.89. Finally, we compared our method with the MQAPs that scored best in the 7th edition of CASP, using CASP7 server models (not included in the MetaMQAP training set) as the test data. In our benchmark, MetaMQAP is outperformed only by PCONS6 and method QA_556 - methods that require comparison of multiple alternative models and score each of them depending on its similarity to other models. MetaMQAP is however the best among methods capable of evaluating just single models. We implemented the MetaMQAP as a web server available for free use by all academic users at the URL https://genesilico.pl/toolkit/

The gait standard deviation, a single measure of kinematic variability.

PubMed

Sangeux, Morgan; Passmore, Elyse; Graham, H Kerr; Tirosh, Oren

2016-05-01

Measurement of gait kinematic variability provides relevant clinical information in certain conditions affecting the neuromotor control of movement. In this article, we present a measure of overall gait kinematic variability, GaitSD, based on combination of waveforms' standard deviation. The waveform standard deviation is the common numerator in established indices of variability such as Kadaba's coefficient of multiple correlation or Winter's waveform coefficient of variation. Gait data were collected on typically developing children aged 6-17 years. Large number of strides was captured for each child, average 45 (SD: 11) for kinematics and 19 (SD: 5) for kinetics. We used a bootstrap procedure to determine the precision of GaitSD as a function of the number of strides processed. We compared the within-subject, stride-to-stride, variability with the, between-subject, variability of the normative pattern. Finally, we investigated the correlation between age and gait kinematic, kinetic and spatio-temporal variability. In typically developing children, the relative precision of GaitSD was 10% as soon as 6 strides were captured. As a comparison, spatio-temporal parameters required 30 strides to reach the same relative precision. The ratio stride-to-stride divided by normative pattern variability was smaller in kinematic variables (the smallest for pelvic tilt, 28%) than in kinetic and spatio-temporal variables (the largest for normalised stride length, 95%). GaitSD had a strong, negative correlation with age. We show that gait consistency may stabilise only at, or after, skeletal maturity. Copyright © 2016 Elsevier B.V. All rights reserved.

Revealing modified gravity signals in matter and halo hierarchical clustering

NASA Astrophysics Data System (ADS)

Hellwing, Wojciech A.; Koyama, Kazuya; Bose, Benjamin; Zhao, Gong-Bo

2017-07-01

We use a set of N-body simulations employing a modified gravity (MG) model with Vainshtein screening to study matter and halo hierarchical clustering. As test-case scenarios we consider two normal branch Dvali-Gabadadze-Porrati (nDGP) gravity models with mild and strong growth rate enhancement. We study higher-order correlation functions ξn(R ) up to n =9 and associated reduced cumulants Sn(R )≡ξn(R )/σ (R )2n -2. We find that the matter probability distribution functions are strongly affected by the fifth force on scales up to 50 h-1 Mpc , and the deviations from general relativity (GR) are maximized at z =0 . For reduced cumulants Sn, we find that at small scales R ≤6 h-1 Mpc the MG is characterized by lower values, with the deviation growing from 7% in the reduced skewness up to even 40% in S5. To study the halo clustering we use a simple abundance matching and divide haloes into thee fixed number density samples. The halo two-point functions are weakly affected, with a relative boost of the order of a few percent appearing only at the smallest pair separations (r ≤5 h-1 Mpc ). In contrast, we find a strong MG signal in Sn(R )'s, which are enhanced compared to GR. The strong model exhibits a >3 σ level signal at various scales for all halo samples and in all cumulants. In this context, we find that the reduced kurtosis to be an especially promising cosmological probe of MG. Even the mild nDGP model leaves a 3 σ imprint at small scales R ≤3 h-1 Mpc , while the stronger model deviates from a GR signature at nearly all scales with a significance of >5 σ . Since the signal is persistent in all halo samples and over a range of scales, we advocate that the reduced kurtosis estimated from galaxy catalogs can potentially constitute a strong MG-model discriminatory as well as GR self-consistency test.

Energy-level repulsion by spin-orbit coupling in two-dimensional Rydberg excitons

NASA Astrophysics Data System (ADS)

Stephanovich, V. A.; Sherman, E. Ya.; Zinner, N. T.; Marchukov, O. V.

2018-05-01

We study the effects of Rashba spin-orbit coupling on two-dimensional Rydberg exciton systems. Using analytical and numerical arguments we demonstrate that this coupling considerably modifies the wave functions and leads to a level repulsion that results in a deviation from the Poissonian statistics of the adjacent level distance distribution. This signifies the crossover to nonintegrability of the system and hints at the possibility of quantum chaos emerging. Such behavior strongly differs from the classical realization, where spin-orbit coupling produces highly entangled, chaotic electron trajectories in an exciton. We also calculate the oscillator strengths and show that randomization appears in the transitions between states with different total momenta.

Strong motions observed by K-NET and KiK-net during the 2016 Kumamoto earthquake sequence

NASA Astrophysics Data System (ADS)

Suzuki, Wataru; Aoi, Shin; Kunugi, Takashi; Kubo, Hisahiko; Morikawa, Nobuyuki; Nakamura, Hiromitsu; Kimura, Takeshi; Fujiwara, Hiroyuki

2017-01-01

The nationwide strong-motion seismograph network of K-NET and KiK-net in Japan successfully recorded the strong ground motions of the 2016 Kumamoto earthquake sequence, which show the several notable characteristics. For the first large earthquake with a JMA magnitude of 6.5 (21:26, April 14, 2016, JST), the large strong motions are concentrated near the epicenter and the strong-motion attenuations are well predicted by the empirical relation for crustal earthquakes with a moment magnitude of 6.1. For the largest earthquake of the sequence with a JMA magnitude of 7.3 (01:25, April 16, 2016, JST), the large peak ground accelerations and velocities extend from the epicentral area to the northeast direction. The attenuation feature of peak ground accelerations generally follows the empirical relation, whereas that for velocities deviates from the empirical relation for stations with the epicentral distance of greater than 200 km, which can be attributed to the large Love wave having a dominant period around 10 s. The large accelerations were observed at stations even in Oita region, more than 70 km northeast from the epicenter. They are attributed to the local induced earthquake in Oita region, whose moment magnitude is estimated to be 5.5 by matching the amplitudes of the corresponding phases with the empirical attenuation relation. The real-time strong-motion observation has a potential for contributing to the mitigation of the ongoing earthquake disasters. We test a methodology to forecast the regions to be exposed to the large shaking in real time, which has been developed based on the fact that the neighboring stations are already shaken, for the largest event of the Kumamoto earthquakes, and demonstrate that it is simple but effective to quickly make warning. We also shows that the interpolation of the strong motions in real time is feasible, which will be utilized for the real-time forecast of ground motions based on the observed shakings.[Figure not available: see fulltext.

Developmental Dyslexia, Neurolinguistic Theory and Deviations in Brain Morphology.

ERIC Educational Resources Information Center

Hynd, George W.; And Others

1991-01-01

Reviews computer tomography and magnetic resonance imaging studies examining deviations in brain morphology. Discusses methodological and technical issues. Concludes that dyslexics show variations in specific brain regions. Suggests that neuroimaging procedures appear to provide direct evidence supporting the importance of deviations in normal…

Potential sources of variability in mesocosm experiments on the response of phytoplankton to ocean acidification

NASA Astrophysics Data System (ADS)

Moreno de Castro, Maria; Schartau, Markus; Wirtz, Kai

2017-04-01

Mesocosm experiments on phytoplankton dynamics under high CO2 concentrations mimic the response of marine primary producers to future ocean acidification. However, potential acidification effects can be hindered by the high standard deviation typically found in the replicates of the same CO2 treatment level. In experiments with multiple unresolved factors and a sub-optimal number of replicates, post-processing statistical inference tools might fail to detect an effect that is present. We propose that in such cases, data-based model analyses might be suitable tools to unearth potential responses to the treatment and identify the uncertainties that could produce the observed variability. As test cases, we used data from two independent mesocosm experiments. Both experiments showed high standard deviations and, according to statistical inference tools, biomass appeared insensitive to changing CO2 conditions. Conversely, our simulations showed earlier and more intense phytoplankton blooms in modeled replicates at high CO2 concentrations and suggested that uncertainties in average cell size, phytoplankton biomass losses, and initial nutrient concentration potentially outweigh acidification effects by triggering strong variability during the bloom phase. We also estimated the thresholds below which uncertainties do not escalate to high variability. This information might help in designing future mesocosm experiments and interpreting controversial results on the effect of acidification or other pressures on ecosystem functions.

Robust tunability of magnetoresistance in half-Heusler R PtBi ( R = Gd , Dy, Tm, and Lu) compounds

DOE PAGES

Mun, Eundeok; Bud'ko, Sergey L.; Canfield, Paul C.

2016-03-15

We present the magnetic field dependencies of transport properties for RPtBi ( R = Gd, Dy, Tm, and Lu) half-Heusler compounds. Temperature- and field-dependent resistivity measurements of high-quality RPtBi single crystals reveal an unusually large, nonsaturating magnetoresistance (MR) up to 300 K under a moderate magnetic field of H = 140 kOe. At 300 K, the large MR effect decreases as the rare earth is traversed from Gd to Lu and the magnetic field dependence of MR shows a deviation from the conventional H2 behavior. The Hall coefficient ( RH) for R = Gd indicates a sign change around 120more » K, whereas RH curves for R = Dy, Tm, and Lu remain positive for all measured temperatures. At 300 K, the Hall resistivity reveals a deviation from the linear field dependence for all compounds. Thermoelectric power measurements on this family show strong temperature and magnetic field dependencies which are consistent with resistivity measurements. A highly enhanced thermoelectric power under applied magnetic field is observed as high as ~100 μV/K at 140 kOe. Furthermore, analysis of the transport data in this series reveals that the rare-earth-based half-Heusler compounds provide opportunities to tune MR effect through lanthanide contraction and to elucidate the mechanism of nontrivial MR.« less

Anomalous scaling of Δ C versus T c in the Fe-based superconductors: the $${S}_{\\pm }$$-wave pairing state model

DOE PAGES

Bang, Yunkyu; Stewart, G. R.

2016-02-01

The strong power law behavior of the specific heat jumpmore » $${\\rm{\\Delta }}C\\;$$ versus T c $$({\\rm{\\Delta }}C/{T}_{{\\rm{c}}}\\sim {T}_{{\\rm{c}}}^{\\alpha },\\alpha \\approx 2)$$, first observed by Bud'ko et al (2009 Phys. Rev. B 79 220516), has been confirmed with several families of the Fe-based superconducting compounds with various dopings. We tested a minimal two band BCS model to understand this anomalous behavior and showed that this non-BCS relation between $${\\rm{\\Delta }}C\\;$$ versus T c is a generic property of the multiband superconducting state paired by a dominant interband interaction ($${V}_{\\mathrm{inter}}\\gt {V}_{\\mathrm{intra}}$$) reflecting the relation $$\\frac{{{\\rm{\\Delta }}}_{{\\rm{h}}}}{{{\\rm{\\Delta }}}_{{\\rm{e}}}}\\sim \\sqrt{\\frac{{N}_{{\\rm{e}}}}{{N}_{{\\rm{h}}}}}$$ near T c, as in the $${S}_{\\pm }$$-wave pairing state. We also found that this $${\\rm{\\Delta }}C\\;$$ versus T c power law can continuously change from the ideal BNC scaling to a considerable deviation by a moderate variation of the impurity scattering rate $${{\\rm{\\Gamma }}}_{0}$$ (non-pair-breaking). Finally, as a result, our model provides a consistent explanation why the electron-doped Fe-based superconductors follow the ideal BNC scaling very well while the hole-doped systems often show varying degree of deviations.« less

Shared Components of Rhythm Generation for Locomotion and Scratching Exist Prior to Motoneurons

PubMed Central

Hao, Zhao-Zhe; Berkowitz, Ari

2017-01-01

Does the spinal cord use a single network to generate locomotor and scratching rhythms or two separate networks? Previous research showed that simultaneous swim and scratch stimulation (“dual stimulation”) in immobilized, spinal turtles evokes a single rhythm in hindlimb motor nerves with a frequency often greater than during swim stimulation alone or scratch stimulation alone. This suggests that the signals that trigger swimming and scratching converge and are integrated within the spinal cord. However, these results could not determine whether the integration occurs in motoneurons themselves or earlier, in spinal interneurons. Here, we recorded intracellularly from hindlimb motoneurons during dual stimulation. Motoneuron membrane potentials displayed regular oscillations at a higher frequency during dual stimulation than during swim or scratch stimulation alone. In contrast, arithmetic addition of the oscillations during swimming alone and scratching alone with various delays always generated irregular oscillations. Also, the standard deviation of the phase-normalized membrane potential during dual stimulation was similar to those during swimming or scratching alone. In contrast, the standard deviation was greater when pooling cycles of swimming alone and scratching alone for two of the three forms of scratching. This shows that dual stimulation generates a single rhythm prior to motoneurons. Thus, either swimming and scratching largely share a rhythm generator or the two rhythms are integrated into one rhythm by strong interactions among interneurons. PMID:28848402

Studies on transport behaviour of a binary liquid mixture of ethanol and toluene at 298.15K in terms of viscosity models

NASA Astrophysics Data System (ADS)

Purohit, Suresh; Suthar, Shyam Sunder; Vyas, Mahendra; Beniwal, Ram Chandra

2018-05-01

The main transport properties of liquid or liquid mixtures are viscosity, diffusion, transference and electrical conductance. Viscosities of various liquid mixtures have been studied and their analyses have also been done by the help of some parameters. For each solution, the excess thermodynamic properties (YE) have been investigated. These excess thermodynamic properties are excess molar volume (VE), viscosity deviation (Δη) and excess Gibbs free energy of activation of viscous flow (ΔG*E). These parameters provide us the important information about interaction between molecules. For example, the negative value of VE and positive value of Δη shows the strong interaction between the solute and solvent molecules while positive value of VE and negative value of Δη shows the weak interaction between solute and solvent molecules. Above parameters and their discussion have been made in our earlier paper. In the present research paper, the viscosity data have been correlated with the equations of Grunberg and Nissan, Hind et al., Tamura and Kurata Katti. The excess values have been correlated using Redlich-Kister polynomial equation to obtain their coefficients and standard deviations. It has been found that in all cases, the data obtained fitted with the values correlated by the corresponding models very well. The results are interpreted in terms of molecular interactions occurring in the solution.

Cooperative Effects of Corticosteroids and Catecholamines upon Immune Deviation of the Type-1/Type-2 Cytokine Balance in Favor of Type-2 Expression in Human Peripheral Blood Mononuclear Cells

NASA Technical Reports Server (NTRS)

Salicru, A. N.; Sams, Clarence F.; Marshall, G. D.

2007-01-01

A growing number of studies show strong associations between stress and altered immune function. In vivo studies of chronic and acute stress have demonstrated that cognitive stressors are strongly correlated with high levels of catecholamines (CT) and corticosteroids (CS). Although both CS and CT individually can inhibit the production of T-helper 1 (TH1, type-1 like) cytokines and simultaneously promote the production of T-helper 2 (TH2, type-2 like) cytokines in antigen-specific and mitogen stimulated human leukocyte cultures in vitro, little attention has been focused on the effects of combination CT and CS in immune responses that may be more physiologically relevant. We therefore investigated the combined effects of in vitro CT and CS upon the type-1/type-2 cytokine balance of human peripheral blood mononuclear cells (PBMC) as a model to study the immunomodulatory effects of superimposed acute and chronic stress. Results demonstrated a significant decrease in type-1 cytokine production (IFN-gamma) and a significant increase in type-2 cytokine production (IL-4, IL-10) in our CS+CT incubated cultures when compared to either CT or CS agents alone. Furthermore, variable enhancement of type-1/type-2 immune deviation occurred depending upon when the CT was added. The data suggest that CS can increase the sensitivity of PBMC to the immunomodulatory effects of CT and establishes an in vitro model to study the combined effects of in vivo type-1/type-2 cytokine alterations observed in acute and chronic stress.

Relationship between chin deviation and the position and morphology of the mandible in individuals with a unilateral cleft lip and palate

PubMed Central

Kim, Kyung-Seon; Park, Soo-Byung; Kim, Seong-Sik; Kim, Yong-Il

2013-01-01

Objective In this study, we aimed to examine the relationship between chin deviation and the positional and morphological features of the mandible and to determine the factors that contributed to chin deviation in individuals with a unilateral cleft lip and palate (UCLP). Methods Cone-beam computed tomography (CBCT) images of 28 adults with UCLP were analyzed in this study. Segmented three-dimensional temporomandibular fossa and mandible images were reconstructed, and angular, linear, and volumetric parameters were measured. Results For all 28 individuals, the chin was found to deviate to the cleft side by 1.59 mm. Moreover, among these 28 individuals, only 7 showed distinct (more than 4 mm) chin deviation, which was toward the cleft side. Compared to the non-cleft side, the mandibular body length, frontal ramal inclination, and vertical position of the condyle were lower and inclination of the temporomandibular fossa was steeper on the cleft side. Furthermore, the differences in inclination of the temporomandibular fossa, mandibular body length, ramus length, and condylar volume ratio (non-deviated/deviated) were positively correlated with chin deviation. Conclusions UCLP individuals show mild chin deviation to the cleft side. Statistical differences were noted in the parameters that represented positional and morphological asymmetries of the mandible and temporomandibular fossa; however, these differences were too small to indicate clinical significance. PMID:24015386

A massive binary black-hole system in OJ 287 and a test of general relativity.

PubMed

Valtonen, M J; Lehto, H J; Nilsson, K; Heidt, J; Takalo, L O; Sillanpää, A; Villforth, C; Kidger, M; Poyner, G; Pursimo, T; Zola, S; Wu, J-H; Zhou, X; Sadakane, K; Drozdz, M; Koziel, D; Marchev, D; Ogloza, W; Porowski, C; Siwak, M; Stachowski, G; Winiarski, M; Hentunen, V-P; Nissinen, M; Liakos, A; Dogru, S

2008-04-17

Tests of Einstein's general theory of relativity have mostly been carried out in weak gravitational fields where the space-time curvature effects are first-order deviations from Newton's theory. Binary pulsars provide a means of probing the strong gravitational field around a neutron star, but strong-field effects may be best tested in systems containing black holes. Here we report such a test in a close binary system of two candidate black holes in the quasar OJ 287. This quasar shows quasi-periodic optical outbursts at 12-year intervals, with two outburst peaks per interval. The latest outburst occurred in September 2007, within a day of the time predicted by the binary black-hole model and general relativity. The observations confirm the binary nature of the system and also provide evidence for the loss of orbital energy in agreement (within 10 per cent) with the emission of gravitational waves from the system. In the absence of gravitational wave emission the outburst would have happened 20 days later.

Adsorption of phospholipids at oil/water interfaces during emulsification is controlled by stress relaxation and diffusion.

PubMed

Hildebrandt, Ellen; Nirschl, Hermann; Kok, Robbert Jan; Leneweit, Gero

2018-05-16

Adsorption of phosphatidylcholines at oil/water interfaces strongly deviates from spread monolayers at air/water surfaces. Understanding its nature and consequences could vastly improve applications in medical nanoemulsions and biotechnologies. Adsorption kinetics at interfaces of water with different oil phases were measured by profile analysis tensiometry. Adsorption kinetics for 2 different phospholipids, DPPC and POPC, as well as 2 organic phases, squalene and squalane, show that formation of interfacial monolayers is initially dominated by stress-relaxation in the first minutes. Diffusion only gradually contributes to a decrease in interfacial tension at later stages of time and higher film pressures. The results can be applied for the optimization of emulsification protocols using mechanical treatments. Emulsions using phospholipids with unsaturated fatty acids are dominated much more strongly by stress-relaxation and cover interfaces very fast compared to those with saturated fatty acids. In contrast, phospholipid layers consisting of saturated fatty acids converge faster towards the equilibrium than those with unsaturated fatty acids.

Grain size analysis and depositional environment of shallow marine to basin floor, Kelantan River Delta

NASA Astrophysics Data System (ADS)

Afifah, M. R. Nurul; Aziz, A. Che; Roslan, M. Kamal

2015-09-01

Sediment samples were collected from the shallow marine from Kuala Besar, Kelantan outwards to the basin floor of South China Sea which consisted of quaternary bottom sediments. Sixty five samples were analysed for their grain size distribution and statistical relationships. Basic statistical analysis like mean, standard deviation, skewness and kurtosis were calculated and used to differentiate the depositional environment of the sediments and to derive the uniformity of depositional environment either from the beach or river environment. The sediments of all areas were varied in their sorting ranging from very well sorted to poorly sorted, strongly negative skewed to strongly positive skewed, and extremely leptokurtic to very platykurtic in nature. Bivariate plots between the grain-size parameters were then interpreted and the Coarsest-Median (CM) pattern showed the trend suggesting relationships between sediments influenced by three ongoing hydrodynamic factors namely turbidity current, littoral drift and waves dynamic, which functioned to control the sediments distribution pattern in various ways.

Enabling electroweak baryogenesis through dark matter

DOE PAGES

Lewicki, Marek; Rindler-Daller, Tanja; Wells, James D.

2016-06-09

We study the impact on electroweak baryogenesis from a swifter cosmological expansion induced by dark matter. We detail the experimental bounds that one can place on models that realize it, and we investigate the modifications of these bounds that result from a non-standard cosmological history. The modifications can be sizeable if the expansion rate of the Universe increases by several orders of magnitude. We illustrate the impact through the example of scalar field dark matter, which can alter the cosmological history enough to enable a strong-enough first-order phase transition in the Standard Model when it is supplemented by a dimensionmore » six operator directly modifying the Higgs boson potential. We show that due to the modified cosmological history, electroweak baryogenesis can be realized, while keeping deviations of the triple Higgs coupling below HL-LHC sensitivies. The required scale of new physics to effectuate a strong-enough first order phase transition can change by as much as twenty percent as the expansion rate increases by six orders of magnitude.« less

Directional learning and the provisioning of public goods

PubMed Central

Nax, Heinrich H.; Perc, Matjaž

2015-01-01

We consider an environment where players are involved in a public goods game and must decide repeatedly whether to make an individual contribution or not. However, players lack strategically relevant information about the game and about the other players in the population. The resulting behavior of players is completely uncoupled from such information, and the individual strategy adjustment dynamics are driven only by reinforcement feedbacks from each player's own past. We show that the resulting “directional learning” is sufficient to explain cooperative deviations away from the Nash equilibrium. We introduce the concept of k–strong equilibria, which nest both the Nash equilibrium and the Aumann-strong equilibrium as two special cases, and we show that, together with the parameters of the learning model, the maximal k–strength of equilibrium determines the stationary distribution. The provisioning of public goods can be secured even under adverse conditions, as long as players are sufficiently responsive to the changes in their own payoffs and adjust their actions accordingly. Substantial levels of public cooperation can thus be explained without arguments involving selflessness or social preferences, solely on the basis of uncoordinated directional (mis)learning. PMID:25619192

Acoustic waves in the solar atmosphere. VII - Non-grey, non-LTE H(-) models

NASA Technical Reports Server (NTRS)

Schmitz, F.; Ulmschneider, P.; Kalkofen, W.

1985-01-01

The propagation and shock formation of radiatively damped acoustic waves in the solar chromosphere are studied under the assumption that H(-) is the only absorber; the opacity is non-grey. Deviations from local thermodynamic equilibrium (LTE) are permitted. The results of numerical simulations show the depth dependence of the heating by the acoustic waves to be insensitive to the mean state of the atmosphere. After the waves have developed into shocks, their energy flux decays exponentially with a constant damping length of about 1.4 times the pressure scale height, independent of initial flux and wave period. Departures from LTE have a strong influence on the mean temperature structure in dynamical chromosphere models; this is even more pronounced in models with reduced particle density - simulating conditions in magnetic flux tubes - which show significantly increased temperatures in response to mechanical heating. When the energy dissipation of the waves is sufficiently large to dissociate most of the H(-) ions, a strong temperature rise is found that is reminiscent of the temperature structure in the transition zone between chromosphere and corona; the energy flux remaining in the waves then drives mass motions.

Remarkably constant PAH concentrations in Swiss soils over the last 30 years.

PubMed

Gubler, Andreas; Wächter, Daniel; Blum, Franziska; Bucheli, Thomas D

2015-10-01

Although polycyclic aromatic hydrocarbons (PAH) are of concern due to their carcinogenic, mutagenic, and teratogenic properties and their ubiquitous occurrence in environmental compartments, only few studies assessed the temporal evolutions of PAH contents of soils over extended time periods. The Swiss Soil Monitoring Network NABO runs long-term monitoring sites resampled every five years since the 1980s. In the present study, soil (0-20 cm) samples collected from 1985 through 2013 at 25 selected monitoring sites were analysed for the 16 priority PAH according to the U.S. EPA and five PAH marker substances. We observed divergent trends for light PAH, such as naphthalene and phenanthrene, compared with heavy PAH, such as benzo[a]pyrene and benzo[ghi]perylene. Whereas the former showed decreasing concentrations since the late 1980s, no significant trends were found for the latter. Furthermore, the analyses showed that naphthalene contents decreased most strongly at rural sites featuring low population densities, while phenanthrene contents generally decreased most strongly at semi-rural sites. The deviating evolutions of light and heavy PAH were mainly attributed to their differing physico-chemical properties. Temporal evolutions in soils contradict emission inventory data suggesting PAH emissions to decline since the 1980s.

Analyzing the "CareGap": assessing gaps in adherence to clinical guidelines in adult soft tissue sarcoma.

PubMed

Waks, Zeev; Goldbraich, Esther; Farkash, Ariel; Torresani, Michele; Bertulli, Rossella; Restifo, Nicola; Locatelli, Paolo; Casali, Paolo; Carmeli, Boaz

2013-01-01

Clinical decision support systems (CDSSs) are gaining popularity as tools that assist physicians in optimizing medical care. These systems typically comply with evidence-based medicine and are designed with input from domain experts. Nonetheless, deviations from CDSS recommendations are abundant across a broad spectrum of disorders, raising the question as to why this phenomenon exists. Here, we analyze this gap in adherence to a clinical guidelines-based CDSS by examining the physician treatment decisions for 1329 adult soft tissue sarcoma patients in northern Italy using patient-specific parameters. Dubbing this analysis "CareGap", we find that deviations correlate strongly with certain disease features such as local versus metastatic clinical presentation. We also notice that deviations from the guideline-based CDSS suggestions occur more frequently for patients with shorter survival time. Such observations can direct physicians' attention to distinct patient cohorts that are prone to higher deviation levels from clinical practice guidelines. This illustrates the value of CareGap analysis in assessing quality of care for subsets of patients within a larger pathology.

The morphological characteristics of the antebrachiocarpal joint of the cheetah (Acinonyx jubatus).

PubMed

Ohale, L O C; Groenewald, H B

2003-03-01

A morphological study of the structures of the antebrachiocarpal (AC) joint of the cheetah was carded out by dissection of eight forelimbs obtained from four adult cheetahs culled from the Kruger National Park, Republic of South Africa. The aim was to evaluate the deviations of this joint from the normal feline pattern and to consider their possible relationship to the cheetah's adaptation to speed. Although published data on the AC joint of the other felids show general resemblance to that of the cheetah, there are nevertheless slight, but significant variations and modifications which tend to suggest adaptation to speed. The shafts of the radius and ulna of the cheetah are relatively straight and slender, with poorly developed distal ends. The ulnar notch is reduced to a very shallow concavity while the corresponding ulnar facet is a barely noticeable convexity, separated from the distal ulnar articular facet by an ill-defined groove. The movement of the distal radio-ulnar joint is highly restricted by the presence of a fibro-cartilaginous structure and a strong interrosseous membrane, limiting pronation and supination normally achieved by the rotation of the radius around the ulna. The extensor grooves at the distal extremity of the radius are deep and narrow and are guarded by prominent ridges. A thick extensor retinaculum anchors the strong extensor tendons in these grooves. The distal articular surface of the radius is concave in all directions except at the point where it moves into its stylold process. At this point it is convex in the dorsopalmar direction, with a surface that is rather deep and narrow. The proximal row of carpal bones presents a strongly convex surface, which is more pronounced in the dorsopalmar direction with the greatest convexity on the lateral aspect. Medially, there is a ridge-like concavity across the base of the tubercle, which rocks on the flexor surface of the radius, limiting excessive flexion as well as restricting lateral deviation of the AC joint.

The relationship between physical workload and quality within line-based assembly.

PubMed

Ivarsson, Anna; Eek, Frida

2016-07-01

Reducing costs and improvement of product quality are considered important to ensure productivity within a company. Quality deviations during production processes and ergonomics have previously shown to be associated. This study explored the relationship between physical workload and real (found during production processes) and potential (need of extra time and assistance to complete tasks) quality deviations in a line-based assembly plant. The physical workload on and the work rotation between 52 workstations were assessed. As the outcome, real and potential quality deviations were studied during 10 weeks. Results show that workstations with higher physical workload had significantly more real deviations compared to lower workload stations. Static work posture had significantly more potential deviations. Rotation between high and low workload was related to fewer quality deviations compared to rotation between only high workload stations. In conclusion, physical ergonomics seems to be related to real and potential quality deviation within line-based assembly. Practitioner Summary: To ensure good productivity in manufacturing industries, it is important to reduce costs and improve product quality. This study shows that high physical workload is associated with quality deviations and need of extra time and assistance to complete tasks within line-based assembly, which can be financially expensive for a company.

Structure–property relations of orthorhombic [(CH{sub 3}){sub 3}NCH{sub 2}COO]{sub 2}(CuCl{sub 2}){sub 3}·2H{sub 2}O

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

Haussühl, Eiken, E-mail: haussuehl@kristall.uni-frankfurt.de; Schreuer, Jürgen; Wiehl, Leonore

2014-04-01

Large single crystals of orthorhombic [(CH{sub 3}){sub 3}NCH{sub 2}COO]{sub 2}(CuCl{sub 2}){sub 3}·2H{sub 2}O with dimensions up to 40×40×30 mm{sup 3} were grown from aqueous solutions. The elastic and piezoelastic coefficients were derived from ultrasonic resonance frequencies and their shifts upon variation of pressure, respectively, using the plate-resonance technique. Additionally, the coefficients of thermal expansion were determined between 95 K and 305 K by dilatometry. The elastic behaviour at ambient conditions is dominated by the 2-dimensional network of strong hydrogen bonds within the (001) plane leading to a corresponding pseudo-tetragonal anisotropy of the longitudinal elastic stiffness. The variation of elastic propertiesmore » with pressure, however, as well as the thermal expansion shows strong deviations from the pseudo-tetragonal symmetry. These deviations are probably correlated with tilts of the elongated tri-nuclear betaine–CuCl{sub 2}–water complexes. Neither the thermal expansion nor the specific heat capacity gives any hint on a phase transition in the investigated temperature range. - Graphical abstract: Single crystal of orthorhombic [(CH{sub 3}){sub 3}NCH{sub 2}COO]{sub 2}(CuCl{sub 2}){sub 3}·2H{sub 2}O. - Highlights: • Large single crystals (40 ×40 ×30 mm{sup 3}) of [(CH{sub 3}){sub 3}NCH{sub 2}COO]{sub 2}(CuCl{sub 2}){sub 3}·2H{sub 2}O were grown. • The elastic and piezoelastic coefficients were derived from ultrasonic resonance frequencies. • Thermal expansion (95 K–305 K) and heat capacity (113 K–323 K) were determined. • The orthorhombic structure shows pseudo-tetragonal elastic anisotropy at ambient conditions. • The crystal structure is stable in the investigated range (1–1600 bar, 95–303 K)« less

The Determination of Relevant Goals and Criteria Used to Select an Automated Patient Care Information System

PubMed Central

Chocholik, Joan K.; Bouchard, Susan E.; Tan, Joseph K. H.; Ostrow, David N.

1999-01-01

Objectives: To determine the relevant weighted goals and criteria for use in the selection of an automated patient care information system (PCIS) using a modified Delphi technique to achieve consensus. Design: A three-phase, six-round modified Delphi process was implemented by a ten-member PCIS selection task force. The first phase consisted of an exploratory round. It was followed by the second phase, of two rounds, to determine the selection goals and finally the third phase, of three rounds, to finalize the selection criteria. Results: Consensus on the goals and criteria for selecting a PCIS was measured during the Delphi process by reviewing the mean and standard deviation of the previous round's responses. After the study was completed, the results were analyzed using a limits-of-agreement indicator that showed strong agreement of each individual's responses between each of the goal determination rounds. Further analysis for variability in the group's response showed a significant movement to consensus after the first goal-determination iteration, with consensus reached on all goals by the end of the second iteration. Conclusion: The results indicated that the relevant weighted goals and criteria used to make the final decision for an automated PCIS were developed as a result of strong agreement among members of the PCIS selection task force. It is therefore recognized that the use of the Delphi process was beneficial in achieving consensus among clinical and nonclinical members in a relatively short time while avoiding a decision based on political biases and the “groupthink” of traditional committee meetings. The results suggest that improvements could be made in lessening the number of rounds by having information available through side conversations, by having other statistical indicators besides the mean and standard deviation available between rounds, and by having a content expert address questions between rounds. PMID:10332655

Probing turbulence with infrared observations in OMC1

NASA Astrophysics Data System (ADS)

Gustafsson, M.; Field, D.; Lemaire, J. L.; Pijpers, F. P.

2006-01-01

A statistical analysis is presented of the turbulent velocity structure in the Orion Molecular Cloud at scales ranging from 70 AU to 3×104 AU. Results are based on IR Fabry-Perot interferometric observations of shock and photon-excited H2 in the K-band S(1) v=1{-}0 line at 2.121 μm and refer to the dynamical characteristics of warm perturbed gas. Data consist of a spatially resolved image with a measured velocity for each resolution limited region (70 AU× 70 AU) in the image. The effect of removal of apparent large scale velocity gradients is discussed and the conclusion drawn that these apparent gradients represent part of the turbulent cascade and should remain within the data. Using our full data set, observations establish that the Larson size-linewidth relation is obeyed to the smallest scales studied here extending the range of validity of this relationship by nearly 2 orders of magnitude. The velocity probability distribution function (PDF) is constructed showing extended exponential wings, providing evidence of intermittency, further supported by the skewness (third moment) and kurtosis (fourth moment) of the velocity distribution. Variance and kurtosis of the PDF of velocity differences are constructed as a function of lag. The variance shows an approximate power law dependence on lag, with exponent significantly lower than the Kolmogorov value, and with deviations below 2000 AU which are attributed to outflows and possibly disk structures associated with low mass star formation within OMC1. The kurtosis shows strong deviation from a Gaussian velocity field, providing evidence of velocity correlations at small lags. Results agree accurately with semi-empirical simulations in Eggers & Wang (1998). In addition, 170 individual H2 emitting clumps have been analysed with sizes between 500 and 2200 AU. These show considerable diversity with regard to PDFs and variance functions (related to second order structure functions) displaying a variety of shapes of the PDF and different values of the scaling exponent within a restricted spatial region. However, a region associated with an outflow from a deeply embedded O-star shows high values of the scaling exponent of the variance function, representing a strong segregation of high and low exponent clumps. Our analysis constitutes the first characterization of the turbulent velocity field at the scale of star formation and provide a dataset which models of star-forming regions should aim to reproduce.

High resolution FTIR spectroscopy of the ν7 band of CD3CCH

NASA Astrophysics Data System (ADS)

Pal, Ayan Kumar; Kshirsagar, R. J.

2018-03-01

The high-resolution Fourier transform spectrum of propyne-d3 (CD3CCH) at room temperature has been recorded in the region of the ν7 band (950-1200 cm-1) at an apodized resolution of 0.004 cm-1. About 2400 lines consisting of a total of 25 sub-bands ranging from KΔK = -13 to 12 have been assigned in the ν7 band of CD3CCH. In the fitting analysis, the ν4 = 1 state to which transitions have not been identified in the experimental spectrum included as a "shadow" state. The data have been analyzed taking into account of the strong x-y Coriolis interaction of the ν7 = 1 state with the ν4 = 1 state. l-type interactions between the ± l components of the ν7 = 1 state, and a weak k-type doubling interaction between ν7 = 1 and ν4 = 1 states have been included in the analysis. The vibration-rotation transitions for K ≥ 8 show fairly large amount of deviation and most likely interacted by other nearby states. The transitions upto K = 7 and Jmax = 61 could be fitted with a standard deviation of 0.0007 cm-1.

Vertex Movement for Mission Status Graphics: A Polar-Star Display

NASA Technical Reports Server (NTRS)

Trujillo, Anna

2002-01-01

Humans are traditionally bad monitors, especially over long periods of time on reliable systems, and they are being called upon to do this more and more as systems become further automated. Because of this, there is a need to find a way to display the monitoring information to the human operator in such a way that he can notice pertinent deviations in a timely manner. One possible solution is to use polar-star displays that will show deviations from normal in a more salient manner. A polar-star display uses a polygon's vertices to report values. An important question arises, though, of how the vertices should move. This experiment investigated two particular issues of how the vertices should move: (1) whether the movement of the vertices should be continuous or discrete and (2) whether the parameters that made up each vertex should always move in one direction regardless of parameter sign or move in both directions indicating parameter sign. The results indicate that relative movement direction is best. Subjects performed better with this movement type and they subjectively preferred it to the absolute movement direction. As for movement type, no strong preferences were shown.

Development and evaluation of a device for simultaneous uniaxial compression and optical imaging of cartilage samples in vitro

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

Steinert, Marian; Kratz, Marita; Jones, David B.

2014-10-15

In this paper, we present a system that allows imaging of cartilage tissue via optical coherence tomography (OCT) during controlled uniaxial unconfined compression of cylindrical osteochondral cores in vitro. We describe the system design and conduct a static and dynamic performance analysis. While reference measurements yield a full scale maximum deviation of 0.14% in displacement, force can be measured with a full scale standard deviation of 1.4%. The dynamic performance evaluation indicates a high accuracy in force controlled mode up to 25 Hz, but it also reveals a strong effect of variance of sample mechanical properties on the tracking performancemore » under displacement control. In order to counterbalance these disturbances, an adaptive feed forward approach was applied which finally resulted in an improved displacement tracking accuracy up to 3 Hz. A built-in imaging probe allows on-line monitoring of the sample via OCT while being loaded in the cultivation chamber. We show that cartilage topology and defects in the tissue can be observed and demonstrate the visualization of the compression process during static mechanical loading.« less

Test of quantum thermalization in the two-dimensional transverse-field Ising model

PubMed Central

Blaß, Benjamin; Rieger, Heiko

2016-01-01

We study the quantum relaxation of the two-dimensional transverse-field Ising model after global quenches with a real-time variational Monte Carlo method and address the question whether this non-integrable, two-dimensional system thermalizes or not. We consider both interaction quenches in the paramagnetic phase and field quenches in the ferromagnetic phase and compare the time-averaged probability distributions of non-conserved quantities like magnetization and correlation functions to the thermal distributions according to the canonical Gibbs ensemble obtained with quantum Monte Carlo simulations at temperatures defined by the excess energy in the system. We find that the occurrence of thermalization crucially depends on the quench parameters: While after the interaction quenches in the paramagnetic phase thermalization can be observed, our results for the field quenches in the ferromagnetic phase show clear deviations from the thermal system. These deviations increase with the quench strength and become especially clear comparing the shape of the thermal and the time-averaged distributions, the latter ones indicating that the system does not completely lose the memory of its initial state even for strong quenches. We discuss our results with respect to a recently formulated theorem on generalized thermalization in quantum systems. PMID:27905523

Determination of Trace lead (II) by Resonance Light Scattering Based on Pb (II)-KI-MG System

NASA Astrophysics Data System (ADS)

Chen, Ninghua; Yang, Yingchun; Hao, Shuai; Li, Yangmin

2018-01-01

In pH=3.0 weak acidic solution, it is found that Pb2+ can react with I-to form [PbI4]2-, and it further reacted with MG to form ion-association complex. As a result, the new spectra of RLS appeared and their intensities enhanced greatly. Accordingly, a new method developed for the determination of Pb (II).The appropriate reaction conditions were optimized through experiments. The results show that a strong and stable resonance scattering spectra emerge at the wavelength of 338 nm. The resonance light scattering strength (ΔIRLS) has good linear relationship with the concentration of Pb (II) in the range of 0.2 μg/mL ~ 1.0 μg/mL. The detection limits (LOD) is 0.0155 μg/mL. The relative standard deviation (RSD) is 3.61% (n=11) for the determination of 0.6 μg/mL Pb (II) standard solution. And this method was successfully applied to the determination of three environmental water samples (nongfu spring, tap water, laboratory wastewater). Results illustrate that the addition standard recovery are 80%~107% with relative standard deviation (RSD) between 1.8% to 4.6%.

Effect of q-nonextensive parameter and saturation time on electron density steepening in electron-positron-ion plasmas

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

Hashemzadeh, M., E-mail: hashemzade@gmail.com

2015-11-15

The effect of q-nonextensive parameter and saturation time on the electron density steepening in electron-positron-ion plasmas is studied by particle in cell method. Phase space diagrams show that the size of the holes, and consequently, the number of trapped particles strongly depends on the q-parameter and saturation time. Furthermore, the mechanism of the instability and exchange of energy between electron-positron and electric field is explained by the profiles of the energy density. Moreover, it is found that the q-parameter, saturation time, and electron and positron velocities affect the nonlinear evolution of the electron density which leads to the steepening ofmore » its structure. The q-nonextensive parameter or degree of nonextensivity is the relation between temperature gradient and potential energy of the system. Therefore, the deviation of q-parameter from unity indicates the degree of inhomogeneity of temperature or deviation from equilibrium. Finally, using the kinetic theory, a generalized q-dispersion relation is presented for electron-positron-ion plasma systems. It is found that the simulation results in the linear regime are in good agreement with the growth rate results obtained by the kinetic theory.« less

An Integrated Model of Application, Admission, Enrollment, and Financial Aid

ERIC Educational Resources Information Center

DesJardins, Stephen L.; Ahlburg, Dennis A.; McCall, Brian Patrick

2006-01-01

We jointly model the application, admission, financial aid determination, and enrollment decision process. We find that expectations of admission affect application probabilities, financial aid expectations affect enrollment and application behavior, and deviations from aid expectations are strongly related to enrollment. We also conduct…

Computing 3-D wavefields in mantle circulations models to test hypotheses on the origin of lower mantle heterogeneity under Africa directly against seismic observations

NASA Astrophysics Data System (ADS)

Schuberth, Bernhard; Zaroli, Christophe; Nolet, Guust

2015-04-01

Of particular interest for the tectonic evolution of the Atlantic region is the influence of lower mantle structure under Africa on flow in the upper mantle beneath the ocean basin. Along with its Pacific counterpart, the large African anomaly in the lowermost mantle with strongly reduced seismic velocities has received considerable attention in seismological and geodynamic studies. Several seismological observations are typically taken as an indication that these two anomalies are being caused by large-scale compositional variations and that they are piles of material with higher density than normal mantle rock. This would imply negative buoyancy in the lowermost mantle under Africa, which has important implications for the flow at shallower depth and inferences on the processes that led to the formation of the Atlantic Ocean basin. However, a large number of recent studies argue for a strong thermal gradient across the core-mantle boundary that might provide an alternative explanation for the lower mantle anomaly through the resulting large lateral temperature variations. Recently, we developed a new joint forward modeling approach to test such geodynamic hypotheses directly against the seismic observations: Seismic heterogeneity is predicted by converting the temperature field of a high-resolution 3-D mantle circulation model into seismic velocities using thermodynamic models of mantle mineralogy. 3-D global wave propagation in the synthetic elastic structures is then simulated using a spectral element method. Being based on forward modelling only, this approach allows us to generate synthetic wavefields and seismograms independently of seismic observations. The statistics of observed long-period body wave traveltime variations show a markedly different behaviour for P- and S-waves: the standard deviation of P-wave delay times stays almost constant with ray turning depth, while that of the S-wave delay times increases strongly throughout the mantle. In an earlier study, we showed that synthetic traveltime variations computed for an isochemical mantle circulation model with strong core heating can reproduce these different trends. This was taken as a strong indication that seismic heterogeneity in the lower mantle is likely dominated by thermal variations on large length-scales (i.e., relevant for long-period body waves). We will discuss the robustness of this earlier conclusion by exploring the uncertainties in the mineralogical models used to convert temperatures to seismic velocities. In particular, we investigate the influence of anelasticity on the standard deviation of our synthetic traveltime variations. Owing to the differences in seismic frequency content between laboratory measurements (MHz to GHz) and the Earth (mHz to Hz), the seismic velocities given in the mineralogical model need to be adjusted; that is, corrected for dispersion due to anelastic effects.

An approximate fluvial equilibrium topography for the Alps

NASA Astrophysics Data System (ADS)

Stüwe, K.; Hergarten, S.

2012-04-01

This contribution addresses the question whether the present topography of the Alps can be approximated by a fluvial equilibrium topography and whether this can be used to determine uplift rates. Based on a statistical analysis of the present topography we use a stream-power approach for erosion where the erosion rate is proportional to the square root of the catchment size for catchment sizes larger than 12 square kilometers and a logarithmic dependence to mimic slope processes at smaller catchment sizes. If we assume a homogeneous uplift rate over the entire region (block uplift), the best-fit fluvial equilibrium topography differs from the real topography by about 500 m RMS (root mean square) with a strong systematic deviation. Regions of low elevation are too high in the equilibrium topography, while high-mountain regions are too low. The RMS difference significantly decreases if a spatially variable uplift function is allowed. If a strong variation of the uplift rate on a scale of 5 km is allowed, the systematic deviation becomes rather small, and the RMS difference decreases to about 150 m. A significant part of the remaining deviation apparently arises from glacially-shaped valleys, while another part may result from prematurity of the relief (Hergarten, Wagner & Stüwe, EPSL 297:453, 2010). The best-fit uplift function can probably be used for forward or backward simulation of the landform evolution.

Correlation between clinical severity and type and degree of pectus excavatum in twelve brachycephalic dogs.

PubMed

Hassan, Elham A; Hassan, Marwa H; Torad, Faisal A

2018-05-18

The aim of the study was to correlate the clinical severity of pectus excavatum with its type and degree based on objective radiographic evaluation. Twelve brachycephalic dogs were included. Grading of the clinical severity was done based on a 6-point grading score. Thoracic radiographs were used to calculate the frontosagittal and vertebral indices at the tenth thoracic vertebra and the vertebra overlying the excavatum. Correlation between the clinical severity score and frontosagittal and vertebral indices was evaluated using Pearson's correlation coefficient. Typical pectus excavatum was recorded in the caudal sternum in seven dogs, with a mean clinical severity score of 1.7 ± 1.4, whereas in five dogs, atypical mid-sternal deviation was recorded with a mean clinical severity score of 3.8 ± 0.7. A strong correlation (r=0.7) was recorded between the clinical severity score and vertebral index in the atypical form, whereas a weak correlation (r=0.02) was recorded in the typical form (P<0.05). The clinical severity and degree of pectus excavatum was poorly correlated (r=0.3) in the typical form of pectus excavatum, whereas it was strongly correlated (r=0.9) in the atypical form. Pectus excavatum in dogs is associated with compressive cardiopulmonary dysfunction, which depends mainly on the site/type of deviation rather than the degree of deviation.

Physically Challenging Song Traits, Male Quality, and Reproductive Success in House Wrens

PubMed Central

Cramer, Emily R. A.

2013-01-01

Physically challenging signals are likely to honestly indicate signaler quality. In trilled bird song two physically challenging parameters are vocal deviation (the speed of sound frequency modulation) and trill consistency (how precisely syllables are repeated). As predicted, in several species, they correlate with male quality, are preferred by females, and/or function in male-male signaling. Species may experience different selective pressures on their songs, however; for instance, there may be opposing selection between song complexity and song performance difficulty, such that in species where song complexity is strongly selected, there may not be strong selection on performance-based traits. I tested whether vocal deviation and trill consistency are signals of male quality in house wrens (Troglodytes aedon), a species with complex song structure. Males’ singing ability did not correlate with male quality, except that older males sang with higher trill consistency, and males with more consistent trills responded more aggressively to playback (although a previous study found no effect of stimulus trill consistency on males’ responses to playback). Males singing more challenging songs did not gain in polygyny, extra-pair paternity, or annual reproductive success. Moreover, none of the standard male quality measures I investigated correlated with mating or reproductive success. I conclude that vocal deviation and trill consistency do not signal male quality in this species. PMID:23527137

CZMIL (coastal zone mapping and imaging lidar): from first flights to first mission through system validation

NASA Astrophysics Data System (ADS)

Feygels, Viktor I.; Park, Joong Yong; Wozencraft, Jennifer; Aitken, Jennifer; Macon, Christopher; Mathur, Abhinav; Payment, Andy; Ramnath, Vinod

2013-06-01

CZMIL is an integrated lidar-imagery system and software suite designed for highly automated generation of physical and environmental information products for coastal zone mapping in the framework of the US Army Corps of Engineers (USACE) National Coastal Mapping Program (NCMP). This paper presents the results of CZMIL system validation in turbid water conditions along the Gulf Coast of Mississippi and in relatively clear water conditions in Florida in late spring 2012. Results of the USACE May-October 2012 mission in Green Bay, WI and Lake Erie are presented. The system performance tests show that CZMIL successfully achieved 7-8m depth in Mississippi with Kd =0.46m-1 (Kd is the diffuse attenuation coefficient) and up to 41m in Florida when Kd=0.11m-1. Bathymetric accuracy of CZMIL was measured by comparing CZMIL depths with multi-beam sonar data from Cat Island, MS and from off the coast of Fort. Lauderdale, FL. Validation demonstrated that CZMIL meets USACE specifications (two standard deviation, 2σ, ~30 cm). To measure topographic accuracy we made direct comparisons of CZMIL elevations to GPS-surveyed ground control points and vehicle-based lidar scans of topographic surfaces. Results confirmed that CZMIL meets the USACE topographic requirements (2σ, ~15 cm). Upon completion of the Green Bay and Lake Erie mission there were 89 flights with 2231 flightlines. The general hours of aircraft engine time (which doesn't include all transit/ferry flights) was 441 hours with 173 hours of time on survey flightlines. The 4.8 billion (!) laser shots and 38.6 billion digitized waveforms covered over 1025 miles of shoreline.

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

Johannsen, Tim; Psaltis, Dimitrios

According to the no-hair theorem, astrophysical black holes are fully characterized by their masses and spins and are described by the Kerr metric. This theorem can be tested observationally by measuring (at least) three different multipole moments of the spacetimes of black holes. In this paper, we calculate the profiles of fluorescent iron lines emitted from the accretion flows around black hole candidates within a framework that allows us to perform the calculation as a function of its mass and spin as well as of a free parameter that measures potential deviations from the Kerr metric. We show that suchmore » deviations lead to line profiles that are significantly altered and may exhibit a modified flux ratio of the two peaks in their characteristic double-peaked shape. We also show that the disk inclination can be measured independently of the spin and the deviation parameter at low to intermediate inclination angles, as in the case of Kerr black holes. We estimate the precision that near-future X-ray missions such as Astro-H and ATHENA+ are required to achieve in order to resolve deviations from the Kerr metric in iron line profiles and show that constraints on such deviations will be strongest for rapidly spinning black holes. More generally, we show that measuring the line profile with a precision of {approx}5% at disk inclinations of 30 Degree-Sign or 60 Degree-Sign constrains the deviation parameter to order unity for values of the spin a {approx}> 0.5M.« less

``The errors were the results of errors'': Promoting Good Writing by Bad Example

NASA Astrophysics Data System (ADS)

Korsunsky, Boris

2010-01-01

We learn best by example—this adage is probably as old as teaching itself. In my own classroom, I have found that very often the students learn best from the "negative" examples. Perhaps, this shouldn't come as a surprise at all. After all, we don't react strongly to the norm—but an obvious deviation from the norm may attract our attention and make for a great teachable moment. And, if the deviation happens to be either scary or funny, the added emotional impact can create a truly powerful and lasting memory in the minds of the students.

Linear maps preserving maximal deviation and the Jordan structure of quantum systems

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

Hamhalter, Jan

2012-12-15

In the algebraic approach to quantum theory, a quantum observable is given by an element of a Jordan algebra and a state of the system is modelled by a normalized positive functional on the underlying algebra. Maximal deviation of a quantum observable is the largest statistical deviation one can obtain in a particular state of the system. The main result of the paper shows that each linear bijective transformation between JBW algebras preserving maximal deviations is formed by a Jordan isomorphism or a minus Jordan isomorphism perturbed by a linear functional multiple of an identity. It shows that only onemore » numerical statistical characteristic has the power to determine the Jordan algebraic structure completely. As a consequence, we obtain that only very special maps can preserve the diameter of the spectra of elements. Nonlinear maps preserving the pseudometric given by maximal deviation are also described. The results generalize hitherto known theorems on preservers of maximal deviation in the case of self-adjoint parts of von Neumann algebras proved by Molnar.« less

Compact objects in relativistic theories of gravity

NASA Astrophysics Data System (ADS)

Okada da Silva, Hector

2017-05-01

In this dissertation we discuss several aspects of compact objects, i.e. neutron stars and black holes, in relativistic theories of gravity. We start by studying the role of nuclear physics (encoded in the so-called equation of state) in determining the properties of neutron stars in general relativity. We show that low-mass neutron stars are potentially useful astrophysical laboratories that can be used to constrain the properties of the equation of state. More specifically, we show that various bulk properties of these objects, such as their quadrupole moment and tidal deformability, are tightly correlated. Next, we develop a formalism that aims to capture how generic modifications from general relativity affect the structure of neutron stars, as predicted by a broad class of gravity theories, in the spirit of the parametrized post-Newtonian formalism (PPN). Our "post-Tolman-Oppenheimer-Volkoff" formalism provides a toolbox to study both stellar structure and the interior/exterior geometries of static, spherically symmetric relativistic stars. We also apply the formalism to parametrize deviations from general relativity in various astrophysical observables related with neutron stars, including surface redshift, apparent radius, Eddington luminosity. We then turn our attention to what is arguably the most well-motivated and well-investigated generalization of general relativity: scalar-tensor theory. We start by considering theories where gravity is mediated by a single extra scalar degree of freedom (in addition to the metric tensor). An interesting class of scalar-tensor theories passes all experimental tests in the weak-field regime of gravity, yet considerably deviates from general relativity in the strong-field regime in the presence of matter. A common assumption in modeling neutron stars is that the pressure within these object is spatially isotropic. We relax this assumption and examine how pressure anisotropy affects the mass, radius and moment of inertia of slowly rotating neutron stars, both in general relativity and in scalar-tensor gravity. We show that a sufficient amount of pressure anisotropy results in neutron star models whose properties in scalar-tensor theory deviate significantly from their general relativistic counterparts. Moreover, the presence of anisotropy allows these deviations to be considerable even for values of the theory's coupling parameter for which neutron stars in scalar-tensor theory would be otherwise indistinguishable from those in general relativity. Within scalar-tensor theory we also investigate the effects of the scalar field on the crustal torsional oscillations of neutron stars, which have been associated to quasi-periodic oscillations in the X-ray spectra in the aftermath of giant flares. We show that the presence of the scalar field has an influence on the thickness of the stellar crust, and investigate how it affects the oscillation frequencies. Deviations from the predictions of general relativity can be large for certain values of the theory's coupling parameter. However, the influence of the scalar field is degenerate with uncertainties in the equation of state of the star's crust and microphysics effects (electron screening) for values of the coupling allowed by binary pulsar observations. We also derive the stellar structure equations for slowly-rotating neutron stars in a broader class of scalar-tensor theories in which matter and scalar field are coupled through the so-called disformal coupling. We study in great detail how the disformal coupling affects the structure of neutron stars, and we investigate the existence of universal (equation of state-independent) relations connecting the stellar compactness and moment of inertia. In particular, we find that these universal relations can deviate considerably from the predictions of general relativity. (Abstract shortened by ProQuest.).

Changing incidence of psychotic disorders among the young in Zurich.

PubMed

Ajdacic-Gross, Vladeta; Lauber, Christoph; Warnke, Inge; Haker, Helene; Murray, Robin M; Rössler, Wulf

2007-09-01

There is controversy over whether the incidence rates of schizophrenia and psychotic disorders have changed in recent decades. To detect deviations from trends in incidence, we analysed admission data of patients with an ICD-8/9/10 diagnosis of psychotic disorders in the Canton Zurich / Switzerland, for the period 1977-2005. The data was derived from the central psychiatric register of the Canton Zurich. Ex-post forecasting with ARIMA (Autoregressive Integrated Moving Average) models was used to assess departures from existing trends. In addition, age-period-cohort analysis was applied to determine hidden birth cohort effects. First admission rates of patients with psychotic disorders were constant in men and showed a downward trend in women. However, the rates in the youngest age groups showed a strong increase in the second half of the 1990's. The trend reversal among the youngest age groups coincides with the increased use of cannabis among young Swiss in the 1990's.

Using satellite measurements of N2O to remove dynamical variability from HCl measurements

NASA Astrophysics Data System (ADS)

Stolarski, Richard S.; Douglass, Anne R.; Strahan, Susan E.

2018-04-01

Column HCl measurements show deviations from the expected slow decline following the regulation of chlorine-containing compounds by the Montreal Protocol. We use the simultaneous measurements of N2O and HCl by the Microwave Limb Sounder (MLS) instrument on the Aura satellite to examine this problem. We find that the use of N2O measurements at a specific altitude to represent the impact of dynamical variability on HCl results in a derived linear trend in HCl that is negative (ranging from -2.5 to 5.3 % decade-1) at all altitudes between 68 and 10 hPa. These trends are at or near 2σ statistical significance at all pressure levels between 68 and 10 hPa. This shows that analysis of simultaneous measurements of several constituents is a useful approach to identify small trends from data records that are strongly influenced by dynamical interannual variability.

Citizen Science Provides Valuable Data for Monitoring Global Night Sky Luminance

PubMed Central

Kyba, Christopher C. M.; Wagner, Janna M.; Kuechly, Helga U.; Walker, Constance E.; Elvidge, Christopher D.; Falchi, Fabio; Ruhtz, Thomas; Fischer, Jürgen; Hölker, Franz

2013-01-01

The skyglow produced by artificial lights at night is one of the most dramatic anthropogenic modifications of Earth's biosphere. The GLOBE at Night citizen science project allows individual observers to quantify skyglow using star maps showing different levels of light pollution. We show that aggregated GLOBE at Night data depend strongly on artificial skyglow, and could be used to track lighting changes worldwide. Naked eye time series can be expected to be very stable, due to the slow pace of human eye evolution. The standard deviation of an individual GLOBE at Night observation is found to be 1.2 stellar magnitudes. Zenith skyglow estimates from the “First World Atlas of Artificial Night Sky Brightness” are tested using a subset of the GLOBE at Night data. Although we find the World Atlas overestimates sky brightness in the very center of large cities, its predictions for Milky Way visibility are accurate. PMID:23677222

VDLLA: A virtual daddy-long legs optimization

NASA Astrophysics Data System (ADS)

Yaakub, Abdul Razak; Ghathwan, Khalil I.

2016-08-01

Swarm intelligence is a strong optimization algorithm based on a biological behavior of insects or animals. The success of any optimization algorithm is depending on the balance between exploration and exploitation. In this paper, we present a new swarm intelligence algorithm, which is based on daddy long legs spider (VDLLA) as a new optimization algorithm with virtual behavior. In VDLLA, each agent (spider) has nine positions which represent the legs of spider and each position represent one solution. The proposed VDLLA is tested on four standard functions using average fitness, Medium fitness and standard deviation. The results of proposed VDLLA have been compared against Particle Swarm Optimization (PSO), Differential Evolution (DE) and Bat Inspired Algorithm (BA). Additionally, the T-Test has been conducted to show the significant deference between our proposed and other algorithms. VDLLA showed very promising results on benchmark test functions for unconstrained optimization problems and also significantly improved the original swarm algorithms.

Organics In Meteorites

NASA Technical Reports Server (NTRS)

Chang, Sherwood

1996-01-01

The variety of classes of organic compounds that occur in carbonaceous meteorites suggests a rich pre-planetary chemistry with possible connections to interstellar, solar nebular and parent body processes. Structural diversity prevails within all classes examined in detail. Among amino acids for instance, all possible isomers are found up to species containing 4-6 carbon atoms, with abundances decreasing with increasing molecular weight. Such diversity seems limited to those carbonaceous meteorites which show evidence of having been exposed to liquid water; meteorites lacking such evidence also show much lower abundances and less structural diversity in their organic contents. This apparent dependency on water suggests a role for cometary ices in the chemical evolution of organic compounds on parent bodies. Measurements of the stable isotope compositions of C, H, N and S in classes of compounds and at the individual compound level show strong deviations from average chondritic values. These deviations are difficult to explain by solar system or parent body processes, and precedents for some of these isotopic anomalies exist in interstellar (e.g., high D/H ratios) and circumstellar chemistry. Therefore, presolar origins for much if not all of the meteoritic organic compounds (or their precursors) is a distinct possibility. In contrast, evidence of solar nebular origins is either lacking or suspect. Results from molecular and isotopic analyses of meteoritic organics, from laboratory simulations and from a model of interstellar grain reactions will be used to flesh out the hypothesis that this material originated with interstellar chemistry, was distributed within the early solar system as cometary ices, and was subsequently altered on meteorite parent bodies to yield the observed compounds.

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

Calder, Stuart A; Cao, Guixin; Okamoto, Satoshi

The J_eff=1/2 state is manifested in systems with large cubic crystal field splitting and spin-orbit coupling that are comparable to the on-site Coulomb interaction, U. 5d transition metal oxides host parameters in this regime and strong evidence for this state in Sr2IrO4, and additional iridates, has been presented. All the candidates, however, deviate from the cubic crystal field required to provide an unmixed canonical J_eff=1/2 state, impacting the development of a robust model of this novel insulating and magnetic state. We present experimental and theoretical results that not only show Ca4IrO6 hosts the state, but furthermore uniquely resides in themore » limit required for a canonical unmixed J_eff=1/2 state.« less

Misery Loves Company? A Meta-Regression Examining Aggregate Unemployment Rates and the Unemployment-Mortality Association

PubMed Central

Roelfs, David J.; Shor, Eran; Blank, Aharon; Schwartz, Joseph E.

2015-01-01

PURPOSE Individual-level unemployment has been consistently linked to poor health and higher mortality, but some scholars have suggested that the negative effect of job loss may be lower during times and in places where aggregate unemployment rates are high. We review three logics associated with this moderation hypothesis: health selection, social isolation, and unemployment stigma. We then test whether aggregate unemployment rates moderate the individual-level association between unemployment and all-cause mortality. METHODS We use 6 meta-regression models (each utilizing a different measure of the aggregate unemployment rate) based on 62 relative all-cause mortality risk estimates from 36 studies (from 15 nations). RESULTS We find that the magnitude of the individual-level unemployment-mortality association is approximately the same during periods of high and low aggregate-level unemployment. Model coefficients (exponentiated) were 1.01 for the crude unemployment rate (p = 0.27), 0.94 for the change in unemployment rate from the previous year (p = 0.46), 1.01 for the deviation of the unemployment rate from the 5-year running average (p = 0.87), 1.01 for the deviation of the unemployment rate from the 10-year running average (p = 0.73), 1.01 for the deviation of the unemployment rate from the overall average (measured as a continuous variable; p = 0.61), and showed no variation across unemployment levels when the deviation of the unemployment rate from the overall average was measured categorically. Heterogeneity between studies was significant (p < .001), supporting the use of the random effects model. CONCLUSIONS We found no strong evidence to suggest that unemployment experiences change when macro-economic conditions change. Efforts to ameliorate the negative social and economic consequences of unemployment should continue to focus on the individual and should be maintained regardless of periodic changes in macro-economic conditions. PMID:25795225

Misery loves company? A meta-regression examining aggregate unemployment rates and the unemployment-mortality association.

PubMed

Roelfs, David J; Shor, Eran; Blank, Aharon; Schwartz, Joseph E

2015-05-01

Individual-level unemployment has been consistently linked to poor health and higher mortality, but some scholars have suggested that the negative effect of job loss may be lower during times and in places where aggregate unemployment rates are high. We review three logics associated with this moderation hypothesis: health selection, social isolation, and unemployment stigma. We then test whether aggregate unemployment rates moderate the individual-level association between unemployment and all-cause mortality. We use six meta-regression models (each using a different measure of the aggregate unemployment rate) based on 62 relative all-cause mortality risk estimates from 36 studies (from 15 nations). We find that the magnitude of the individual-level unemployment-mortality association is approximately the same during periods of high and low aggregate-level unemployment. Model coefficients (exponentiated) were 1.01 for the crude unemployment rate (P = .27), 0.94 for the change in unemployment rate from the previous year (P = .46), 1.01 for the deviation of the unemployment rate from the 5-year running average (P = .87), 1.01 for the deviation of the unemployment rate from the 10-year running average (P = .73), 1.01 for the deviation of the unemployment rate from the overall average (measured as a continuous variable; P = .61), and showed no variation across unemployment levels when the deviation of the unemployment rate from the overall average was measured categorically. Heterogeneity between studies was significant (P < .001), supporting the use of the random effects model. We found no strong evidence to suggest that unemployment experiences change when macroeconomic conditions change. Efforts to ameliorate the negative social and economic consequences of unemployment should continue to focus on the individual and should be maintained regardless of periodic changes in macroeconomic conditions. Copyright © 2015 Elsevier Inc. All rights reserved.

An activity index for geomagnetic paleosecular variation, excursions, and reversals

NASA Astrophysics Data System (ADS)

Panovska, S.; Constable, C. G.

2017-04-01

Magnetic indices provide quantitative measures of space weather phenomena that are widely used by researchers in geomagnetism. We introduce an index focused on the internally generated field that can be used to evaluate long term variations or climatology of modern and paleomagnetic secular variation, including geomagnetic excursions, polarity reversals, and changes in reversal rate. The paleosecular variation index, Pi, represents instantaneous or average deviation from a geocentric axial dipole field using normalized ratios of virtual geomagnetic pole colatitude and virtual dipole moment. The activity level of the index, σPi, provides a measure of field stability through the temporal standard deviation of Pi. Pi can be calculated on a global grid from geomagnetic field models to reveal large scale geographic variations in field structure. It can be determined for individual time series, or averaged at local, regional, and global scales to detect long term changes in geomagnetic activity, identify excursions, and transitional field behavior. For recent field models, Pi ranges from less than 0.05 to 0.30. Conventional definitions for geomagnetic excursions are characterized by Pi exceeding 0.5. Strong field intensities are associated with low Pi unless they are accompanied by large deviations from axial dipole field directions. σPi provides a measure of geomagnetic stability that is modulated by the level of PSV or frequency of excursional activity and reversal rate. We demonstrate uses of Pi for paleomagnetic observations and field models and show how it could be used to assess whether numerical simulations of the geodynamo exhibit Earth-like properties.

Interrelations between orthostatic postural deviations and subjects' age, sex, malocclusion, and specific signs and symptoms of functional pathologies of the temporomandibular system: a preliminary correlation and regression study.

PubMed

Munhoz, Wagner Cesar; Hsing, Wu Tu

2014-07-01

Studies on the relationships between postural deviations and the temporomandibular system (TS) functional health are controversial and inconclusive. This study stems from the hypothesis that such inconclusiveness is due to authors considering functional pathologies of the TS (FPTS) as a whole, without taking into account subjects' specific FPTS signs and symptoms. Based on the author and collaborators' previous studies, the present study analyzed data on body posture from a sample of 50 subjects with (30) and without (20) FPTS. Correlation analyses were applied, taking as independent variables age, sex, Helkimo anamnestic, occlusal, and dysfunction indices, as well as FPTS specific signs and symptoms. Postural assessments of the head, cervical spine, shoulders, lumbar spine, and hips were the dependent variables. Linear regression equations were built that proved to partially predict the presence and magnitude of body posture deviations by drawing on subjects' characteristics and specific FPTS symptoms. Determination coefficients for these equations ranged from 0.082 to 0.199 in the univariate, and from 0.121 to 0.502 in the multivariate regression analyses. Results show that factors intrinsic to the subjects or the TS may potentially interfere in results of studies that analyze relationships between FPTS and body posture. Furthermore, a trend to specificity was found, e.g. the degree of cervical lordosis was found to correlate to age and FPTS degree of severity, suggesting that some TS pathological features, or malocclusion, age or sex, may be more strongly correlated than others with specific posture patterns.

CAD/CAM produces dentures with improved fit.

PubMed

Steinmassl, Otto; Dumfahrt, Herbert; Grunert, Ingrid; Steinmassl, Patricia-Anca

2018-02-22

Resin polymerisation shrinkage reduces the congruence of the denture base with denture-bearing tissues and thereby decreases the retention of conventionally fabricated dentures. CAD/CAM denture manufacturing is a subtractive process, and polymerisation shrinkage is not an issue anymore. Therefore, CAD/CAM dentures are assumed to show a higher denture base congruence than conventionally fabricated dentures. It has been the aim of this study to test this hypothesis. CAD/CAM dentures provided by four different manufacturers (AvaDent, Merz Dental, Whole You, Wieland/Ivoclar) were generated from ten different master casts. Ten conventional dentures (pack and press, long-term heat polymerisation) made from the same master casts served as control group. The master casts and all denture bases were scanned and matched digitally. The absolute incongruences were measured using a 2-mm mesh. Conventionally fabricated dentures showed a mean deviation of 0.105 mm, SD = 0.019 from the master cast. All CAD/CAM dentures showed lower mean incongruences. From all CAD/CAM dentures, AvaDent Digital Dentures showed the highest congruence with the master cast surface with a mean deviation of 0.058 mm, SD = 0.005. Wieland Digital Dentures showed a mean deviation of 0.068 mm, SD = 0.005, Whole You Nexteeth prostheses showed a mean deviation of 0.074 mm, SD = 0.011 and Baltic Denture System prostheses showed a mean deviation of 0.086 mm, SD = 0.012. CAD/CAM produces dentures with better fit than conventional dentures. The present study explains the clinically observed enhanced retention and lower traumatic ulcer-frequency in CAD/CAM dentures.

Box-Cox transformation of firm size data in statistical analysis

NASA Astrophysics Data System (ADS)

Chen, Ting Ting; Takaishi, Tetsuya

2014-03-01

Firm size data usually do not show the normality that is often assumed in statistical analysis such as regression analysis. In this study we focus on two firm size data: the number of employees and sale. Those data deviate considerably from a normal distribution. To improve the normality of those data we transform them by the Box-Cox transformation with appropriate parameters. The Box-Cox transformation parameters are determined so that the transformed data best show the kurtosis of a normal distribution. It is found that the two firm size data transformed by the Box-Cox transformation show strong linearity. This indicates that the number of employees and sale have the similar property as a firm size indicator. The Box-Cox parameters obtained for the firm size data are found to be very close to zero. In this case the Box-Cox transformations are approximately a log-transformation. This suggests that the firm size data we used are approximately log-normal distributions.

Structural modeling of carbonaceous mesophase amphotropic mixtures under uniaxial extensional flow.

PubMed

Golmohammadi, Mojdeh; Rey, Alejandro D

2010-07-21

The extended Maier-Saupe model for binary mixtures of model carbonaceous mesophases (uniaxial discotic nematogens) under externally imposed flow, formulated in previous studies [M. Golmohammadi and A. D. Rey, Liquid Crystals 36, 75 (2009); M. Golmohammadi and A. D. Rey, Entropy 10, 183 (2008)], is used to characterize the effect of uniaxial extensional flow and concentration on phase behavior and structure of these mesogenic blends. The generic thermorheological phase diagram of the single-phase binary mixture, given in terms of temperature (T) and Deborah (De) number, shows the existence of four T-De transition lines that define regions that correspond to the following quadrupolar tensor order parameter structures: (i) oblate (perpendicular, parallel), (ii) prolate (perpendicular, parallel), (iii) scalene O(perpendicular, parallel), and (iv) scalene P(perpendicular, parallel), where the symbols (perpendicular, parallel) indicate alignment of the tensor order ellipsoid with respect to the extension axis. It is found that with increasing T the dominant component of the mixture exhibits weak deviations from the well-known pure species response to uniaxial extensional flow (uniaxial perpendicular nematic-->biaxial nematic-->uniaxial parallel paranematic). In contrast, the slaved component shows a strong deviation from the pure species response. This deviation is dictated by the asymmetric viscoelastic coupling effects emanating from the dominant component. Changes in conformation (oblate <==> prolate) and orientation (perpendicular <==> parallel) are effected through changes in pairs of eigenvalues of the quadrupolar tensor order parameter. The complexity of the structural sensitivity to temperature and extensional flow is a reflection of the dual lyotropic/thermotropic nature (amphotropic nature) of the mixture and their cooperation/competition. The analysis demonstrates that the simple structures (biaxial nematic and uniaxial paranematic) observed in pure discotic mesogens under uniaxial extensional flow are significantly enriched by the interaction of the lyotropic/thermotropic competition with the binary molecular architectures and with the quadrupolar nature of the flow.

Coherence Properties of Strongly Interacting Atomic Vapors in Waveguides

DTIC Science & Technology

2011-12-31

lattice in the mean-field regime [22]. There the goal was to repeat, for our system, the Chirikiov-lzrailev program for Fermi- Pasta -Ulam chain and...define a typical deviation from ergodicity), we introduce a geometric structure— based on the Frobenius or Hilbert-Schmidt inner product—to the space of

The Ghanaian Economic Recovery

DTIC Science & Technology

2013-12-01

Adjustment Programs6 instituted by the IMF and World Bank, combined with currency devaluation and smaller government, are responsible for Ghana’s recent...study shows that every negative deviation year was preceded by protectionist policies, and, with one exception (explained by currency devaluation ...negative deviation year was preceded by protectionist policies, and, with one exception (explained by currency devaluation ), every positive deviation

Introducing a Method for Calculating the Allocation of Attention in a Cognitive “Two-Armed Bandit” Procedure: Probability Matching Gives Way to Maximizing

PubMed Central

Heyman, Gene M.; Grisanzio, Katherine A.; Liang, Victor

2016-01-01

We tested whether principles that describe the allocation of overt behavior, as in choice experiments, also describe the allocation of cognition, as in attention experiments. Our procedure is a cognitive version of the “two-armed bandit choice procedure.” The two-armed bandit procedure has been of interest to psychologistsand economists because it tends to support patterns of responding that are suboptimal. Each of two alternatives provides rewards according to fixed probabilities. The optimal solution is to choose the alternative with the higher probability of reward on each trial. However, subjects often allocate responses so that the probability of a response approximates its probability of reward. Although it is this result which has attracted most interest, probability matching is not always observed. As a function of monetary incentives, practice, and individual differences, subjects tend to deviate from probability matching toward exclusive preference, as predicted by maximizing. In our version of the two-armed bandit procedure, the monitor briefly displayed two, small adjacent stimuli that predicted correct responses according to fixed probabilities, as in a two-armed bandit procedure. We show that in this setting, a simple linear equation describes the relationship between attention and correct responses, and that the equation’s solution is the allocation of attention between the two stimuli. The calculations showed that attention allocation varied as a function of the degree to which the stimuli predicted correct responses. Linear regression revealed a strong correlation (r = 0.99) between the predictiveness of a stimulus and the probability of attending to it. Nevertheless there were deviations from probability matching, and although small, they were systematic and statistically significant. As in choice studies, attention allocation deviated toward maximizing as a function of practice, feedback, and incentives. Our approach also predicts the frequency of correct guesses and the relationship between attention allocation and response latencies. The results were consistent with these two predictions, the assumptions of the equations used to calculate attention allocation, and recent studies which show that predictiveness and reward are important determinants of attention. PMID:27014109

Strong Coupling Corrections in Quantum Thermodynamics

NASA Astrophysics Data System (ADS)

Perarnau-Llobet, M.; Wilming, H.; Riera, A.; Gallego, R.; Eisert, J.

2018-03-01

Quantum systems strongly coupled to many-body systems equilibrate to the reduced state of a global thermal state, deviating from the local thermal state of the system as it occurs in the weak-coupling limit. Taking this insight as a starting point, we study the thermodynamics of systems strongly coupled to thermal baths. First, we provide strong-coupling corrections to the second law applicable to general systems in three of its different readings: As a statement of maximal extractable work, on heat dissipation, and bound to the Carnot efficiency. These corrections become relevant for small quantum systems and vanish in first order in the interaction strength. We then move to the question of power of heat engines, obtaining a bound on the power enhancement due to strong coupling. Our results are exemplified on the paradigmatic non-Markovian quantum Brownian motion.

Propagation of rotational Risley-prism-array-based Gaussian beams in turbulent atmosphere

NASA Astrophysics Data System (ADS)

Chen, Feng; Ma, Haotong; Dong, Li; Ren, Ge; Qi, Bo; Tan, Yufeng

2018-03-01

Limited by the size and weight of prism and optical assembling, Rotational Risley-prism-array system is a simple but effective way to realize high power and superior beam quality of deflecting laser output. In this paper, the propagation of the rotational Risley-prism-array-based Gaussian beam array in atmospheric turbulence is studied in detail. An analytical expression for the average intensity distribution at the receiving plane is derived based on nonparaxial ray tracing method and extended Huygens-Fresnel principle. Power in the diffraction-limited bucket is chosen to evaluate beam quality. The effect of deviation angle, propagation distance and intensity of turbulence on beam quality is studied in detail by quantitative simulation. It reveals that with the propagation distance increasing, the intensity distribution gradually evolves from multiple-petal-like shape into the pattern that contains one main-lobe in the center with multiple side-lobes in weak turbulence. The beam quality of rotational Risley-prism-array-based Gaussian beam array with lower deviation angle is better than its counterpart with higher deviation angle when propagating in weak and medium turbulent (i.e. Cn2 < 10-13m-2/3), the beam quality of higher deviation angle arrays degrades faster as the intensity of turbulence gets stronger. In the case of propagating in strong turbulence, the long propagation distance (i.e. z > 10km ) and deviation angle have no influence on beam quality.

ECG-Based Detection of Early Myocardial Ischemia in a Computational Model: Impact of Additional Electrodes, Optimal Placement, and a New Feature for ST Deviation

PubMed Central

Schulze, Walther H. W.; Jiang, Yuan; Wilhelms, Mathias; Luik, Armin; Dössel, Olaf; Seemann, Gunnar

2015-01-01

In case of chest pain, immediate diagnosis of myocardial ischemia is required to respond with an appropriate treatment. The diagnostic capability of the electrocardiogram (ECG), however, is strongly limited for ischemic events that do not lead to ST elevation. This computational study investigates the potential of different electrode setups in detecting early ischemia at 10 minutes after onset: standard 3-channel and 12-lead ECG as well as body surface potential maps (BSPMs). Further, it was assessed if an additional ECG electrode with optimized position or the right-sided Wilson leads can improve sensitivity of the standard 12-lead ECG. To this end, a simulation study was performed for 765 different locations and sizes of ischemia in the left ventricle. Improvements by adding a single, subject specifically optimized electrode were similar to those of the BSPM: 2–11% increased detection rate depending on the desired specificity. Adding right-sided Wilson leads had negligible effect. Absence of ST deviation could not be related to specific locations of the ischemic region or its transmurality. As alternative to the ST time integral as a feature of ST deviation, the K point deviation was introduced: the baseline deviation at the minimum of the ST-segment envelope signal, which increased 12-lead detection rate by 7% for a reasonable threshold. PMID:26587538

ECG-Based Detection of Early Myocardial Ischemia in a Computational Model: Impact of Additional Electrodes, Optimal Placement, and a New Feature for ST Deviation.

PubMed

Loewe, Axel; Schulze, Walther H W; Jiang, Yuan; Wilhelms, Mathias; Luik, Armin; Dössel, Olaf; Seemann, Gunnar

2015-01-01

In case of chest pain, immediate diagnosis of myocardial ischemia is required to respond with an appropriate treatment. The diagnostic capability of the electrocardiogram (ECG), however, is strongly limited for ischemic events that do not lead to ST elevation. This computational study investigates the potential of different electrode setups in detecting early ischemia at 10 minutes after onset: standard 3-channel and 12-lead ECG as well as body surface potential maps (BSPMs). Further, it was assessed if an additional ECG electrode with optimized position or the right-sided Wilson leads can improve sensitivity of the standard 12-lead ECG. To this end, a simulation study was performed for 765 different locations and sizes of ischemia in the left ventricle. Improvements by adding a single, subject specifically optimized electrode were similar to those of the BSPM: 2-11% increased detection rate depending on the desired specificity. Adding right-sided Wilson leads had negligible effect. Absence of ST deviation could not be related to specific locations of the ischemic region or its transmurality. As alternative to the ST time integral as a feature of ST deviation, the K point deviation was introduced: the baseline deviation at the minimum of the ST-segment envelope signal, which increased 12-lead detection rate by 7% for a reasonable threshold.

Thomson scattering diagnostics of thermal plasmas: Laser heating of electrons and the existence of local thermodynamic equilibrium.

PubMed

Murphy, A B

2004-01-01

A number of assessments of electron temperatures in atmospheric-pressure arc plasmas using Thomson scattering of laser light have recently been published. However, in this method, the electron temperature is perturbed due to strong heating of the electrons by the incident laser beam. This heating was taken into account by measuring the electron temperature as a function of the laser pulse energy, and linearly extrapolating the results to zero pulse energy to obtain an unperturbed electron temperature. In the present paper, calculations show that the laser heating process has a highly nonlinear dependence on laser power, and that the usual linear extrapolation leads to an overestimate of the electron temperature, typically by 5000 K. The nonlinearity occurs due to the strong dependence on electron temperature of the absorption of laser energy and of the collisional and radiative cooling of the heated electrons. There are further problems in deriving accurate electron temperatures from laser scattering due to necessary averages that have to be made over the duration of the laser pulse and over the finite volume from which laser light is scattered. These problems are particularly acute in measurements in which the laser beam is defocused in order to minimize laser heating; this can lead to the derivation of electron temperatures that are significantly greater than those existing anywhere in the scattering volume. It was concluded from the earlier Thomson scattering measurements that there were significant deviations from equilibrium between the electron and heavy-particle temperatures at the center of arc plasmas of industrial interest. The present calculations indicate that such deviations are only of the order of 1000 K in 20 000 K, so that the usual approximation that arc plasmas are approximately in local thermodynamic equilibrium still applies.

Effects of the scatter in sunspot group tilt angles on the large-scale magnetic field at the solar surface

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

Jiang, J.; Cameron, R. H.; Schüssler, M., E-mail: jiejiang@nao.cas.cn

The tilt angles of sunspot groups represent the poloidal field source in Babcock-Leighton-type models of the solar dynamo and are crucial for the build-up and reversals of the polar fields in surface flux transport (SFT) simulations. The evolution of the polar field is a consequence of Hale's polarity rules, together with the tilt angle distribution which has a systematic component (Joy's law) and a random component (tilt-angle scatter). We determine the scatter using the observed tilt angle data and study the effects of this scatter on the evolution of the solar surface field using SFT simulations with flux input basedmore » upon the recorded sunspot groups. The tilt angle scatter is described in our simulations by a random component according to the observed distributions for different ranges of sunspot group size (total umbral area). By performing simulations with a number of different realizations of the scatter we study the effect of the tilt angle scatter on the global magnetic field, especially on the evolution of the axial dipole moment. The average axial dipole moment at the end of cycle 17 (a medium-amplitude cycle) from our simulations was 2.73 G. The tilt angle scatter leads to an uncertainty of 0.78 G (standard deviation). We also considered cycle 14 (a weak cycle) and cycle 19 (a strong cycle) and show that the standard deviation of the axial dipole moment is similar for all three cycles. The uncertainty mainly results from the big sunspot groups which emerge near the equator. In the framework of Babcock-Leighton dynamo models, the tilt angle scatter therefore constitutes a significant random factor in the cycle-to-cycle amplitude variability, which strongly limits the predictability of solar activity.« less

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

Brock, K; Lee, C; Samuels, S

Purpose: Tools are now available to perform daily dose assessment in radiotherapy, however, guidance is lacking as to when to replan to limit increase in normal tissue dose. This work performs statistical analysis to provide guidance for when adaptive replanning may be necessary for head/neck (HN) patients. Methods: Planning CT and daily kVCBCT images for 50 HN patients treated with VMAT were retrospectively evaluated. Twelve of 50 patients were replanned due to anatomical changes noted over their RT course. Daily dose assessment was performed to calculate the variation between the planned and delivered dose for the 38 patients not replannedmore » and the patients replanned using their delivered plan. In addition, for the replanned patients, the dose that would have been delivered if the plan was not modified was also quantified. Deviations in dose were analyzed before and after replanning, the daily variations in patients who were not replanned assessed, and the predictive power of the deviation after 1, 5, and 15 fractions determined. Results: Dose deviations were significantly reduced following replanning, compared to if the original plan would have been delivered for the entire course. Early deviations were significantly correlated with total deviations (p<0.01). Using the criteria that a 10% increase in the final delivered dose indicates a replan may be needed earlier in the treatment course, the following guidelines can be made with a 90% specificity after the first 5 fractions: deviations of 7% in the mean dose to the inferior constrictors and 5% in the mean dose to the parotid glands and submandibular glands. No significant dose deviations were observed in any patients for the CTV -70Gy (max deviation 4%). Conclusions: A 5–7% increase in mean dose to normal tissues within the first 5 fractions strongly correlate to an overall deviatios in the delivered dose for HN patients. This work is funded in part by NIH 2P01CA059827-16.« less

Analysis of variability of tropical Pacific sea surface temperatures

NASA Astrophysics Data System (ADS)

Davies, Georgina; Cressie, Noel

2016-11-01

Sea surface temperature (SST) in the Pacific Ocean is a key component of many global climate models and the El Niño-Southern Oscillation (ENSO) phenomenon. We shall analyse SST for the period November 1981-December 2014. To study the temporal variability of the ENSO phenomenon, we have selected a subregion of the tropical Pacific Ocean, namely the Niño 3.4 region, as it is thought to be the area where SST anomalies indicate most clearly ENSO's influence on the global atmosphere. SST anomalies, obtained by subtracting the appropriate monthly averages from the data, are the focus of the majority of previous analyses of the Pacific and other oceans' SSTs. Preliminary data analysis showed that not only Niño 3.4 spatial means but also Niño 3.4 spatial variances varied with month of the year. In this article, we conduct an analysis of the raw SST data and introduce diagnostic plots (here, plots of variability vs. central tendency). These plots show strong negative dependence between the spatial standard deviation and the spatial mean. Outliers are present, so we consider robust regression to obtain intercept and slope estimates for the 12 individual months and for all-months-combined. Based on this mean-standard deviation relationship, we define a variance-stabilizing transformation. On the transformed scale, we describe the Niño 3.4 SST time series with a statistical model that is linear, heteroskedastic, and dynamical.

A bench-top megavoltage fan-beam CT using CdWO4-photodiode detectors. I. System description and detector characterization.

PubMed

Rathee, S; Tu, D; Monajemi, T T; Rickey, D W; Fallone, B G

2006-04-01

We describe the components of a bench-top megavoltage computed tomography (MVCT) scanner that uses an 80-element detector array consisting of CdWO4 scintillators coupled to photodiodes. Each CdWO4 crystal is 2.75 x 8 x 10 mm3. The detailed design of the detector array, timing control, and multiplexer are presented. The detectors show a linear response to dose (dose rate was varied by changing the source to detector distance) with a correlation coefficient (R2) nearly unity with the standard deviation of signal at each dose being less than 0.25%. The attenuation of a 6 MV beam by solid water measured by this detector array indicates a small, yet significant spectral hardening that needs to be corrected before image reconstruction. The presampled modulation transfer function is strongly affected by the detector's large pitch and a large improvement can be obtained by reducing the detector pitch. The measured detective quantum efficiency at zero spatial frequency is 18.8% for 6 MV photons which will reduce the dose to the patient in MVCT applications. The detector shows a less than a 2% reduction in response for a dose of 24.5 Gy accumulated in 2 h; however, the lost response is recovered on the following day. A complete recovery can be assumed within the experimental uncertainty (standard deviation <0.5%); however, any smaller permanent damage could not be assessed.

Adjusting head circumference for covariates in autism: clinical correlates of a highly heritable continuous trait.

PubMed

Chaste, Pauline; Klei, Lambertus; Sanders, Stephan J; Murtha, Michael T; Hus, Vanessa; Lowe, Jennifer K; Willsey, A Jeremy; Moreno-De-Luca, Daniel; Yu, Timothy W; Fombonne, Eric; Geschwind, Daniel; Grice, Dorothy E; Ledbetter, David H; Lord, Catherine; Mane, Shrikant M; Lese Martin, Christa; Martin, Donna M; Morrow, Eric M; Walsh, Christopher A; Sutcliffe, James S; State, Matthew W; Devlin, Bernie; Cook, Edwin H; Kim, Soo-Jeong

2013-10-15

Brain development follows a different trajectory in children with autism spectrum disorders (ASD) than in typically developing children. A proxy for neurodevelopment could be head circumference (HC), but studies assessing HC and its clinical correlates in ASD have been inconsistent. This study investigates HC and clinical correlates in the Simons Simplex Collection cohort. We used a mixed linear model to estimate effects of covariates and the deviation from the expected HC given parental HC (genetic deviation). After excluding individuals with incomplete data, 7225 individuals in 1891 families remained for analysis. We examined the relationship between HC/genetic deviation of HC and clinical parameters. Gender, age, height, weight, genetic ancestry, and ASD status were significant predictors of HC (estimate of the ASD effect = .2 cm). HC was approximately normally distributed in probands and unaffected relatives, with only a few outliers. Genetic deviation of HC was also normally distributed, consistent with a random sampling of parental genes. Whereas larger HC than expected was associated with ASD symptom severity and regression, IQ decreased with the absolute value of the genetic deviation of HC. Measured against expected values derived from covariates of ASD subjects, statistical outliers for HC were uncommon. HC is a strongly heritable trait, and population norms for HC would be far more accurate if covariates including genetic ancestry, height, and age were taken into account. The association of diminishing IQ with absolute deviation from predicted HC values suggests HC could reflect subtle underlying brain development and warrants further investigation. © 2013 Society of Biological Psychiatry.

Adjusting head circumference for covariates in autism: clinical correlates of a highly heritable continuous trait

PubMed Central

Chaste, Pauline; Klei, Lambertus; Sanders, Stephan J.; Murtha, Michael T.; Hus, Vanessa; Lowe, Jennifer K.; Willsey, A. Jeremy; Moreno-De-Luca, Daniel; Yu, Timothy W.; Fombonne, Eric; Geschwind, Daniel; Grice, Dorothy E.; Ledbetter, David H.; Lord, Catherine; Mane, Shrikant M.; Martin, Christa Lese; Martin, Donna M.; Morrow, Eric M.; Walsh, Christopher A.; Sutcliffe, James S.; State, Matthew W.; Devlin, Bernie; Cook, Edwin H.; Kim, Soo-Jeong

2013-01-01

BACKGROUND Brain development follows a different trajectory in children with Autism Spectrum Disorders (ASD) than in typically developing children. A proxy for neurodevelopment could be head circumference (HC), but studies assessing HC and its clinical correlates in ASD have been inconsistent. This study investigates HC and clinical correlates in the Simons Simplex Collection cohort. METHODS We used a mixed linear model to estimate effects of covariates and the deviation from the expected HC given parental HC (genetic deviation). After excluding individuals with incomplete data, 7225 individuals in 1891 families remained for analysis. We examined the relationship between HC/genetic deviation of HC and clinical parameters. RESULTS Gender, age, height, weight, genetic ancestry and ASD status were significant predictors of HC (estimate of the ASD effect=0.2cm). HC was approximately normally distributed in probands and unaffected relatives, with only a few outliers. Genetic deviation of HC was also normally distributed, consistent with a random sampling of parental genes. Whereas larger HC than expected was associated with ASD symptom severity and regression, IQ decreased with the absolute value of the genetic deviation of HC. CONCLUSIONS Measured against expected values derived from covariates of ASD subjects, statistical outliers for HC were uncommon. HC is a strongly heritable trait and population norms for HC would be far more accurate if covariates including genetic ancestry, height and age were taken into account. The association of diminishing IQ with absolute deviation from predicted HC values suggests HC could reflect subtle underlying brain development and warrants further investigation. PMID:23746936

Complexity analysis based on generalized deviation for financial markets

NASA Astrophysics Data System (ADS)

Li, Chao; Shang, Pengjian

2018-03-01

In this paper, a new modified method is proposed as a measure to investigate the correlation between past price and future volatility for financial time series, known as the complexity analysis based on generalized deviation. In comparison with the former retarded volatility model, the new approach is both simple and computationally efficient. The method based on the generalized deviation function presents us an exhaustive way showing the quantization of the financial market rules. Robustness of this method is verified by numerical experiments with both artificial and financial time series. Results show that the generalized deviation complexity analysis method not only identifies the volatility of financial time series, but provides a comprehensive way distinguishing the different characteristics between stock indices and individual stocks. Exponential functions can be used to successfully fit the volatility curves and quantify the changes of complexity for stock market data. Then we study the influence for negative domain of deviation coefficient and differences during the volatile periods and calm periods. after the data analysis of the experimental model, we found that the generalized deviation model has definite advantages in exploring the relationship between the historical returns and future volatility.

Unification of small and large time scales for biological evolution: deviations from power law.

PubMed

Chowdhury, Debashish; Stauffer, Dietrich; Kunwar, Ambarish

2003-02-14

We develop a unified model that describes both "micro" and "macro" evolutions within a single theoretical framework. The ecosystem is described as a dynamic network; the population dynamics at each node of this network describes the "microevolution" over ecological time scales (i.e., birth, ageing, and natural death of individual organisms), while the appearance of new nodes, the slow changes of the links, and the disappearance of existing nodes accounts for the "macroevolution" over geological time scales (i.e., the origination, evolution, and extinction of species). In contrast to several earlier claims in the literature, we observe strong deviations from power law in the regime of long lifetimes.

Current from a nano-gap hyperbolic diode using shape-factors: Theory

NASA Astrophysics Data System (ADS)

Jensen, Kevin L.; Shiffler, Donald A.; Peckerar, Martin; Harris, John R.; Petillo, John J.

2017-08-01

Quantum tunneling by field emission from nanoscale features or sharp field emission structures for which the anode-cathode gap is nanometers in scale ("nano diodes") experience strong deviations from the planar image charge lowered tunneling barrier used in the Murphy and Good formulation of the Fowler-Nordheim equation. These deviations alter the prediction of total current from a curved surface. Modifications to the emission barrier are modeled using a hyperbolic (prolate spheroidal) geometry to determine the trajectories along which the Gamow factor in a WKB-like treatment is undertaken; a quadratic equivalent potential is determined, and a method of shape factors is used to evaluate the corrected total current from a protrusion or wedge geometry.

Results of the eruptive column model inter-comparison study

USGS Publications Warehouse

Costa, Antonio; Suzuki, Yujiro; Cerminara, M.; Devenish, Ben J.; Esposti Ongaro, T.; Herzog, Michael; Van Eaton, Alexa; Denby, L.C.; Bursik, Marcus; de' Michieli Vitturi, Mattia; Engwell, S.; Neri, Augusto; Barsotti, Sara; Folch, Arnau; Macedonio, Giovanni; Girault, F.; Carazzo, G.; Tait, S.; Kaminski, E.; Mastin, Larry G.; Woodhouse, Mark J.; Phillips, Jeremy C.; Hogg, Andrew J.; Degruyter, Wim; Bonadonna, Costanza

2016-01-01

This study compares and evaluates one-dimensional (1D) and three-dimensional (3D) numerical models of volcanic eruption columns in a set of different inter-comparison exercises. The exercises were designed as a blind test in which a set of common input parameters was given for two reference eruptions, representing a strong and a weak eruption column under different meteorological conditions. Comparing the results of the different models allows us to evaluate their capabilities and target areas for future improvement. Despite their different formulations, the 1D and 3D models provide reasonably consistent predictions of some of the key global descriptors of the volcanic plumes. Variability in plume height, estimated from the standard deviation of model predictions, is within ~ 20% for the weak plume and ~ 10% for the strong plume. Predictions of neutral buoyancy level are also in reasonably good agreement among the different models, with a standard deviation ranging from 9 to 19% (the latter for the weak plume in a windy atmosphere). Overall, these discrepancies are in the range of observational uncertainty of column height. However, there are important differences amongst models in terms of local properties along the plume axis, particularly for the strong plume. Our analysis suggests that the simplified treatment of entrainment in 1D models is adequate to resolve the general behaviour of the weak plume. However, it is inadequate to capture complex features of the strong plume, such as large vortices, partial column collapse, or gravitational fountaining that strongly enhance entrainment in the lower atmosphere. We conclude that there is a need to more accurately quantify entrainment rates, improve the representation of plume radius, and incorporate the effects of column instability in future versions of 1D volcanic plume models.

A comparative study of surface waves inversion techniques at strong motion recording sites in Greece

USGS Publications Warehouse

Panagiotis C. Pelekis,; Savvaidis, Alexandros; Kayen, Robert E.; Vlachakis, Vasileios S.; Athanasopoulos, George A.

2015-01-01

Surface wave method was used for the estimation of Vs vs depth profile at 10 strong motion stations in Greece. The dispersion data were obtained by SASW method, utilizing a pair of electromechanical harmonic-wave source (shakers) or a random source (drop weight). In this study, three inversion techniques were used a) a recently proposed Simplified Inversion Method (SIM), b) an inversion technique based on a neighborhood algorithm (NA) which allows the incorporation of a priori information regarding the subsurface structure parameters, and c) Occam's inversion algorithm. For each site constant value of Poisson's ratio was assumed (ν=0.4) since the objective of the current study is the comparison of the three inversion schemes regardless the uncertainties resulting due to the lack of geotechnical data. A penalty function was introduced to quantify the deviations of the derived Vs profiles. The Vs models are compared as of Vs(z), Vs30 and EC8 soil category, in order to show the insignificance of the existing variations. The comparison results showed that the average variation of SIM profiles is 9% and 4.9% comparing with NA and Occam's profiles respectively whilst the average difference of Vs30 values obtained from SIM is 7.4% and 5.0% compared with NA and Occam's.

High-T c superconductivity in undoped ThFeAsN.

PubMed

Shiroka, T; Shang, T; Wang, C; Cao, G-H; Eremin, I; Ott, H-R; Mesot, J

2017-07-31

Unlike the widely studied ReFeAsO series, the newly discovered iron-based superconductor ThFeAsN exhibits a remarkably high critical temperature of 30 K, without chemical doping or external pressure. Here we investigate in detail its magnetic and superconducting properties via muon-spin rotation/relaxation and nuclear magnetic resonance techniques and show that ThFeAsN exhibits strong magnetic fluctuations, suppressed below ~35 K, but no magnetic order. This contrasts strongly with the ReFeAsO series, where stoichiometric parent materials order antiferromagnetically and superconductivity appears only upon doping. The ThFeAsN case indicates that Fermi-surface modifications due to structural distortions and correlation effects are as important as doping in inducing superconductivity. The direct competition between antiferromagnetism and superconductivity, which in ThFeAsN (as in LiFeAs) occurs at already zero doping, may indicate a significant deviation of the s-wave superconducting gap in this compound from the standard s ± scenario.Exploring the interplay between the superconducting gap and the antiferromagnetic phase in Fe-based superconductors remains an open issue. Here, the authors show that Fermi-surface modifications by means of structural distortions and correlation effects are as important as doping in inducing superconductivity in undoped ThFeAsN.

Interfacial Coupling and Electronic Structure of Two-Dimensional Silicon Grown on the Ag(111) Surface at High Temperature.

PubMed

Feng, Jiagui; Wagner, Sean R; Zhang, Pengpeng

2015-06-18

Freestanding silicene, a monolayer of Si arranged in a honeycomb structure, has been predicted to give rise to massless Dirac fermions, akin to graphene. However, Si structures grown on a supporting substrate can show properties that strongly deviate from the freestanding case. Here, combining scanning tunneling microscopy/spectroscopy and differential conductance mapping, we show that the electrical properties of the (√3 x √3) phase of few-layer Si grown on Ag(111) strongly depend on film thickness, where the electron phase coherence length decreases and the free-electron-like surface state gradually diminishes when approaching the interface. These features are presumably attributable to the inelastic inter-band electron-electron scattering originating from the overlap between the surface state, interface state and the bulk state of the substrate. We further demonstrate that the intrinsic electronic structure of the as grown (√3 x √3) phase is identical to that of the (√3 x √3)R30° reconstructed Ag on Si(111), both of which exhibit the parabolic energy-momentum dispersion relation with comparable electron effective masses. These findings highlight the essential role of interfacial coupling on the properties of two-dimensional Si structures grown on supporting substrates, which should be thoroughly scrutinized in pursuit of silicene.

Left-right and Yin-Yang balance of biophoton emission from hands.

PubMed

Yang, Joon-mo; Choi, Chunho; Hyun-hee; Woo, Won-myung; Yi, Seung-ho; Soh, Kwang-sup; Yang, Jong Soo; Choi, C

2004-01-01

Yearlong measurements of biophotons from palm and back of hand of three healthy people were performed. The detection of biophoton was done with two photomultiplier tubes whose spectral range was from 300 nm to 650 nm. The measurement was done on a circular area of diameter 46 mm whose centers were at the acupuncture point Laogong (PC8) of a palm and the mid-point of a back, respectively. The emission rates from the dorsa showed strong seasonal dependence which is consistent with the active nature of Yang meridians, while the palm sides show less seasonal dependence as they belong to the passive Yin meridians. This could be quantified simply by the standard deviations from the yearly average: They were 47.6 counts per second (cps), 66.1 cps and 66.0 cps from the dorsa, and 23.8 cps, 29.7 cps and 30.4 cps from the palms of subject 1, 2 and 3, respectively. Biophoton emission revealed qualitative individual tendencies: The subjects 1 and 2 emitted more strongly from the left dorsa, while the subject 3 from the right dorsum. The left-right balance of biophoton emission was well kept for normal people, which is in contrast with the severe imbalance for some stroke patients. Thus biophoton measurement has a diagnostic potential that encourages more studies.

Reconciling Intuitive Physics and Newtonian Mechanics for Colliding Objects

ERIC Educational Resources Information Center

Sanborn, Adam N.; Mansinghka, Vikash K.; Griffiths, Thomas L.

2013-01-01

People have strong intuitions about the influence objects exert upon one another when they collide. Because people's judgments appear to deviate from Newtonian mechanics, psychologists have suggested that people depend on a variety of task-specific heuristics. This leaves open the question of how these heuristics could be chosen, and how to…

A Monte Carlo Approach to Unidimensionality Testing in Polytomous Rasch Models

ERIC Educational Resources Information Center

Christensen, Karl Bang; Kreiner, Svend

2007-01-01

Many statistical tests are designed to test the different assumptions of the Rasch model, but only few are directed at detecting multidimensionality. The Martin-Lof test is an attractive approach, the disadvantage being that its null distribution deviates strongly from the asymptotic chi-square distribution for most realistic sample sizes. A Monte…

Red, Straight, no bends: primordial power spectrum reconstruction from CMB and large-scale structure

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

Ravenni, Andrea; Verde, Licia; Cuesta, Antonio J., E-mail: andrea.ravenni@pd.infn.it, E-mail: liciaverde@icc.ub.edu, E-mail: ajcuesta@icc.ub.edu

2016-08-01

We present a minimally parametric, model independent reconstruction of the shape of the primordial power spectrum. Our smoothing spline technique is well-suited to search for smooth features such as deviations from scale invariance, and deviations from a power law such as running of the spectral index or small-scale power suppression. We use a comprehensive set of the state-of the art cosmological data: Planck observations of the temperature and polarisation anisotropies of the cosmic microwave background, WiggleZ and Sloan Digital Sky Survey Data Release 7 galaxy power spectra and the Canada-France-Hawaii Lensing Survey correlation function. This reconstruction strongly supports the evidencemore » for a power law primordial power spectrum with a red tilt and disfavours deviations from a power law power spectrum including small-scale power suppression such as that induced by significantly massive neutrinos. This offers a powerful confirmation of the inflationary paradigm, justifying the adoption of the inflationary prior in cosmological analyses.« less

Red, Straight, no bends: primordial power spectrum reconstruction from CMB and large-scale structure

NASA Astrophysics Data System (ADS)

Ravenni, Andrea; Verde, Licia; Cuesta, Antonio J.

2016-08-01

We present a minimally parametric, model independent reconstruction of the shape of the primordial power spectrum. Our smoothing spline technique is well-suited to search for smooth features such as deviations from scale invariance, and deviations from a power law such as running of the spectral index or small-scale power suppression. We use a comprehensive set of the state-of the art cosmological data: Planck observations of the temperature and polarisation anisotropies of the cosmic microwave background, WiggleZ and Sloan Digital Sky Survey Data Release 7 galaxy power spectra and the Canada-France-Hawaii Lensing Survey correlation function. This reconstruction strongly supports the evidence for a power law primordial power spectrum with a red tilt and disfavours deviations from a power law power spectrum including small-scale power suppression such as that induced by significantly massive neutrinos. This offers a powerful confirmation of the inflationary paradigm, justifying the adoption of the inflationary prior in cosmological analyses.

Age-independent anti-Müllerian hormone (AMH) standard deviation scores to estimate ovarian function.

PubMed

Helden, Josef van; Weiskirchen, Ralf

2017-06-01

To determine single year age-specific anti-Müllerian hormone (AMH) standard deviation scores (SDS) for women associated to normal ovarian function and different ovarian disorders resulting in sub- or infertility. Determination of particular year median and mean AMH values with standard deviations (SD), calculation of age-independent cut off SDS for the discrimination between normal ovarian function and ovarian disorders. Single-year-specific median, mean, and SD values have been evaluated for the Beckman Access AMH immunoassay. While the decrease of both median and mean AMH values is strongly correlated with increasing age, calculated SDS values have been shown to be age independent with the differentiation between normal ovarian function measured as occurred ovulation with sufficient luteal activity compared with hyperandrogenemic cycle disorders or anovulation associated with high AMH values and reduced ovarian activity or insufficiency associated with low AMH, respectively. These results will be helpful for the treatment of patients and the ventilation of the different reproductive options. Copyright © 2017 Elsevier B.V. All rights reserved.

Large deviations and mixing for dissipative PDEs with unbounded random kicks

NASA Astrophysics Data System (ADS)

Jakšić, V.; Nersesyan, V.; Pillet, C.-A.; Shirikyan, A.

2018-02-01

We study the problem of exponential mixing and large deviations for discrete-time Markov processes associated with a class of random dynamical systems. Under some dissipativity and regularisation hypotheses for the underlying deterministic dynamics and a non-degeneracy condition for the driving random force, we discuss the existence and uniqueness of a stationary measure and its exponential stability in the Kantorovich-Wasserstein metric. We next turn to the large deviations principle (LDP) and establish its validity for the occupation measures of the Markov processes in question. The proof is based on Kifer’s criterion for non-compact spaces, a result on large-time asymptotics for generalised Markov semigroup, and a coupling argument. These tools combined together constitute a new approach to LDP for infinite-dimensional processes without strong Feller property in a non-compact space. The results obtained can be applied to the two-dimensional Navier-Stokes system in a bounded domain and to the complex Ginzburg-Landau equation.

Early Emission from Type Ia Supernovae

NASA Astrophysics Data System (ADS)

Rabinak, Itay; Livne, Eli; Waxman, Eli

2012-09-01

A unique feature of deflagration-to-detonation (DDT) white dwarf explosion models of supernovae of type Ia is the presence of a strong shock wave propagating through the outer envelope. We consider the early emission expected in such models, which is produced by the expanding shock-heated outer part of the ejecta and precedes the emission driven by radioactive decay. We expand on earlier analyses by considering the modification of the pre-detonation density profile by the weak shocks generated during the deflagration phase, the time evolution of the opacity, and the deviation of the post-shock equation of state from that obtained for radiation pressure domination. A simple analytic model is presented and shown to provide an acceptable approximation to the results of one-dimensional numerical DDT simulations. Our analysis predicts a ~103 s long UV/optical flash with a luminosity of ~1 to ~3 × 1039 erg s-1. Lower luminosity corresponds to faster (turbulent) deflagration velocity. The luminosity of the UV flash is predicted to be strongly suppressed at t > t drop ~ 1 hr due to the deviation from pure radiation domination.

Experimental investigation of unsteady flows at large incidence angles in a linear oscillating cascade

NASA Technical Reports Server (NTRS)

Buffum, Daniel H.; King, Aaron J.; Capece, Vincent R.; El-Aini, Yehia M.

1996-01-01

The aerodynamics of a cascade of airfoils oscillating in torsion about the midchord is investigated experimentally at a large mean incidence angle and, for reference, at a low mean incidence angle. The airfoil section is representative of a modern, low aspect ratio, fan blade tip section. Time-dependent airfoil surface pressure measurements were made for reduced frequencies up to 0.8 for out-of-phase oscillations at Mach numbers up to 0.8 and chordal incidence angles of 0 deg and 10 deg. For the 10 deg chordal incidence angle, a separation bubble formed at the leading edge of the suction surface. The separated flow field was found to have a dramatic effect on the chordwise distribution of the unsteady pressure. In this region, substantial deviations from the attached flow data were found with the deviations becoming less apparent in the aft region of the airfoil for all reduced frequencies. In particular, near the leading edge the separated flow had a strong destabilizing influence while the attached flow had a strong stabilizing influence.

Oscillating cascade aerodynamics at large mean incidence

NASA Technical Reports Server (NTRS)

Buffum, Daniel H.; King, Aaron J.; El-Aini, Yehia M.; Capece, Vincent R.

1996-01-01

The aerodynamics of a cascade of airfoils oscillating in torsion about the midchord is investigated experimentally at a large mean incidence angle and, for reference, at a low mean incidence angle. The airfoil section is representative of a modern, low aspect ratio, fan blade tip section. Time-dependent airfoil surface pressure measurements were made for reduced frequencies of up to 1.2 for out-of-phase oscillations at a Mach number of 0.5 and chordal incidence angles of 0 deg and 10 deg; the Reynolds number was 0.9 x l0(exp 6). For the 10 deg chordal incidence angle, a separation bubble formed at the leading edge of the suction surface. The separated flow field was found to have a dramatic effect on the chordwise distribution of the unsteady pressure. In this region, substantial deviations from the attached flow data were found with the deviations becoming less apparent in the aft region of the airfoil for all reduced frequencies. In particular, near the leading edge the separated flow had a strong destabilizing influence while the attached flow had a strong stabilizing influence.

Reliability of voxel gray values in cone beam computed tomography for preoperative implant planning assessment.

PubMed

Parsa, Azin; Ibrahim, Norliza; Hassan, Bassam; Motroni, Alessandro; van der Stelt, Paul; Wismeijer, Daniel

2012-01-01

To assess the reliability of cone beam computed tomography (CBCT) voxel gray value measurements using Hounsfield units (HU) derived from multislice computed tomography (MSCT) as a clinical reference (gold standard). Ten partially edentulous human mandibular cadavers were scanned by two types of computed tomography (CT) modalities: multislice CT and cone beam CT. On MSCT scans, eight regions of interest (ROI) designating the site for preoperative implant placement were selected in each mandible. The datasets from both CT systems were matched using a three-dimensional (3D) registration algorithm. The mean voxel gray values of the region around the implant sites were compared between MSCT and CBCT. Significant differences between the mean gray values obtained by CBCT and HU by MSCT were found. In all the selected ROIs, CBCT showed higher mean values than MSCT. A strong correlation (R=0.968) between mean voxel gray values of CBCT and mean HU of MSCT was determined. Voxel gray values from CBCT deviate from actual HU units. However, a strong linear correlation exists, which may permit deriving actual HU units from CBCT using linear regression models.

Singlet-catalyzed electroweak phase transitions and precision Higgs boson studies

NASA Astrophysics Data System (ADS)

Profumo, Stefano; Ramsey-Musolf, Michael J.; Wainwright, Carroll L.; Winslow, Peter

2015-02-01

We update the phenomenology of gauge-singlet extensions of the Standard Model scalar sector and their implications for the electroweak phase transition. Considering the introduction of one real scalar singlet to the scalar potential, we analyze present constraints on the potential parameters from Higgs coupling measurements at the Large Hadron Collider (LHC) and electroweak precision observables for the kinematic regime in which no new scalar decay modes arise. We then show how future precision measurements of Higgs boson signal strengths and the Higgs self-coupling could probe the scalar potential parameter space associated with a strong first-order electroweak phase transition. We illustrate using benchmark precision for several future collider options, including the high-luminosity LHC, the International Linear Collider, Triple-Large Electron-Positron collider, the China Electron-Positron Collider, and a 100 TeV proton-proton collider, such as the Very High Energy LHC or the Super Proton-Proton Collider. For the regions of parameter space leading to a strong first-order electroweak phase transition, we find that there exists considerable potential for observable deviations from purely Standard Model Higgs properties at these prospective future colliders.

Convergent chaos

NASA Astrophysics Data System (ADS)

Pradas, Marc; Pumir, Alain; Huber, Greg; Wilkinson, Michael

2017-07-01

Chaos is widely understood as being a consequence of sensitive dependence upon initial conditions. This is the result of an instability in phase space, which separates trajectories exponentially. Here, we demonstrate that this criterion should be refined. Despite their overall intrinsic instability, trajectories may be very strongly convergent in phase space over extremely long periods, as revealed by our investigation of a simple chaotic system (a realistic model for small bodies in a turbulent flow). We establish that this strong convergence is a multi-facetted phenomenon, in which the clustering is intense, widespread and balanced by lacunarity of other regions. Power laws, indicative of scale-free features, characterize the distribution of particles in the system. We use large-deviation and extreme-value statistics to explain the effect. Our results show that the interpretation of the ‘butterfly effect’ needs to be carefully qualified. We argue that the combination of mixing and clustering processes makes our specific model relevant to understanding the evolution of simple organisms. Lastly, this notion of convergent chaos, which implies the existence of conditions for which uncertainties are unexpectedly small, may also be relevant to the valuation of insurance and futures contracts.

Non-Newtonian flow of an ultralow-melting chalcogenide liquid in strongly confined geometry

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

Wang, Siyuan; Jain, Chhavi; Wondraczek, Katrin

2015-05-18

The flow of high-viscosity liquids inside micrometer-size holes can be substantially different from the flow in the bulk, non-confined state of the same liquid. Such non-Newtonian behavior can be employed to generate structural anisotropy in the frozen-in liquid, i.e., in the glassy state. Here, we report on the observation of non-Newtonian flow of an ultralow melting chalcogenide glass inside a silica microcapillary, leading to a strong deviation of the shear viscosity from its value in the bulk material. In particular, we experimentally show that the viscosity is radius-dependent, which is a clear indication that the microscopic rearrangement of the glassmore » network needs to be considered if the lateral confinement falls below a certain limit. The experiments have been conducted using pressure-assisted melt filling, which provides access to the rheological properties of high-viscosity melt flow under previously inaccessible experimental conditions. The resulting flow-induced structural anisotropy can pave the way towards integration of anisotropic glasses inside hybrid photonic waveguides.« less

Labor union members play an OLG repeated game

PubMed Central

Kandori, Michihiro; Obayashi, Shinya

2014-01-01

Humans are capable of cooperating with one another even when it is costly and a deviation provides an immediate gain. An important reason is that cooperation is reciprocated or rewarded and deviations are penalized in later stages. For cooperation to be sustainable, not only must rewards and penalties be strong enough but individuals should also have the right incentives to provide rewards and punishments. Codes of conduct with such properties have been studied extensively in game theory (as repeated game equilibria), and the literature on the evolution of cooperation shows how equilibrium behavior might emerge and proliferate in society. We found that community unions, a subclass of labor unions that admits individual affiliations, are ideal to corroborate these theories with reality, because (i) their activities are simple and (ii) they have a structure that closely resembles a theoretical model, the overlapping generations repeated game. A detailed case study of a community union revealed a possible equilibrium that can function under the very limited observability in the union. The equilibrium code of conduct appears to be a natural focal point based on simple heuristic reasoning. The union we studied was created out of necessity for cooperation, without knowing or anticipating how cooperation might be sustained. The union has successfully resolved about 3,000 labor disputes and created a number of offspring. PMID:25024211

Neutral biogeography and the evolution of climatic niches.

PubMed

Boucher, Florian C; Thuiller, Wilfried; Davies, T Jonathan; Lavergne, Sébastien

2014-05-01

Recent debate on whether climatic niches are conserved through time has focused on how phylogenetic niche conservatism can be measured by deviations from a Brownian motion model of evolutionary change. However, there has been no evaluation of this methodological approach. In particular, the fact that climatic niches are usually obtained from distribution data and are thus heavily influenced by biogeographic factors has largely been overlooked. Our main objective here was to test whether patterns of climatic niche evolution that are frequently observed might arise from neutral dynamics rather than from adaptive scenarios. We developed a model inspired by neutral biodiversity theory, where individuals disperse, compete, and undergo speciation independently of climate. We then sampled the climatic niches of species according to their geographic position and showed that even when species evolve independently of climate, their niches can nonetheless exhibit evolutionary patterns strongly differing from Brownian motion. Indeed, climatic niche evolution is better captured by a model of punctuated evolution with constraints due to landscape boundaries, two features that are traditionally interpreted as evidence for selective processes acting on the niche. We therefore suggest that deviation from Brownian motion alone should not be used as evidence for phylogenetic niche conservatism but that information on phenotypic traits directly linked to physiology is required to demonstrate that climatic niches have been conserved through time.

Neutral biogeography and the evolution of climatic niches

PubMed Central

Boucher, Florian C.; Thuiller, Wilfried; Davies, T. Jonathan; Lavergne, Sébastien

2014-01-01

Recent debate on whether climatic niches are conserved through time has focused on how phylogenetic niche conservatism can be measured by deviations from a Brownian motion model of evolutionary change. However, there has been no evaluation of this methodological approach. In particular, the fact that climatic niches are usually obtained from distribution data and are thus heavily influenced by biogeographic factors has largely been overlooked. Our main objective here was to test whether patterns of climatic niche evolution that are frequently observed might arise from neutral dynamics rather than adaptive scenarios. We develop a model inspired by Neutral Biodiversity Theory, where individuals disperse, compete, and undergo speciation independently of climate. We then sample the climatic niches of species according to their geographic position and show that even when species evolved independently of climate, their niches can nonetheless exhibit evolutionary patterns strongly differing from Brownian motion. Indeed, climatic niche evolution is better captured by a model of punctuated evolution with constraints due to landscape boundaries, two features that are traditionally interpreted as evidence for selective processes acting on the niche. We therefore suggest that deviation from Brownian motion alone should not be used as evidence for phylogenetic niche conservatism, but that information on phenotypic traits directly linked to physiology is required to demonstrate that climatic niches have been conserved through time. PMID:24739191

When Can Species Abundance Data Reveal Non-neutrality?

PubMed Central

Al Hammal, Omar; Alonso, David; Etienne, Rampal S.; Cornell, Stephen J.

2015-01-01

Species abundance distributions (SAD) are probably ecology’s most well-known empirical pattern, and over the last decades many models have been proposed to explain their shape. There is no consensus over which model is correct, because the degree to which different processes can be discerned from SAD patterns has not yet been rigorously quantified. We present a power calculation to quantify our ability to detect deviations from neutrality using species abundance data. We study non-neutral stochastic community models, and show that the presence of non-neutral processes is detectable if sample size is large enough and/or the amplitude of the effect is strong enough. Our framework can be used for any candidate community model that can be simulated on a computer, and determines both the sampling effort required to distinguish between alternative processes, and a range for the strength of non-neutral processes in communities whose patterns are statistically consistent with neutral theory. We find that even data sets of the scale of the 50 Ha forest plot on Barro Colorado Island, Panama, are unlikely to be large enough to detect deviations from neutrality caused by competitive interactions alone, though the presence of multiple non-neutral processes with contrasting effects on abundance distributions may be detectable. PMID:25793889

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

Ahadi, S., E-mail: su4idi@yahoo.com; Puspito, N. T.; Ibrahim, G.

Determination of onset time precursors of strong earthquakes (Mw > 5) and distance (d < 500 km) using geomagnetic data from Geomagnetic station KTB, Sumatra and two station references DAV, Philippine and DAW, Australia. separate techniques are required in its determination. Not the same as that recorded in the kinetic wave seismograms can be determined by direct time domain. Difficulties associated with electromagnetic waves seismogenic activities require analysis of the transformed signal in the frequency domain. Determination of the frequency spectrum will determine the frequency of emissions emitted from the earthquake source. The aim is to analyze the power amplitudemore » of the ULF emissions in the horizontal component (H) and vertical component (Z). Polarization power ratio Z/H is used for determining the sign of earthquake precursors controlled by the standard deviation. The pattern recognition polarization ratio should be obtained which can differentiate emissions from seismogenic effects of geomagnetic activity. ULF emission patterns generated that seismogenic effect has duration > 5 days and the dominance of emission intensity recorded at the Z component and for the dominance of the emission intensity of geomagnetic activity recorded in the component H. The result shows that the onset time is determined when the polarization power ratio Z/H standard deviation over the limit (p ± 2 σ) which has a duration of > 5 days.« less

Scaling theory of temporal correlations and size-dependent fluctuations in the traded value of stocks

NASA Astrophysics Data System (ADS)

Eisler, Zoltán; Kertész, János

2006-04-01

Records of the traded value fi of stocks display fluctuation scaling, a proportionality between the standard deviation σi and the average ⟨fi⟩ : σi∝⟨fi⟩α , with a strong time scale dependence α(Δt) . The nontrivial (i.e., neither 0.5 nor 1) value of α may have different origins and provides information about the microscopic dynamics. We present a set of stylized facts and then show their connection to such behavior. The functional form α(Δt) originates from two aspects of the dynamics: Stocks of larger companies both tend to be traded in larger packages and also display stronger correlations of traded value. The results are integrated into a general framework that can be applied to a wide range of complex systems.

40 CFR 63.8640 - What records must I keep?

Code of Federal Regulations, 2010 CFR

2010-07-01

... to show continuous compliance with each emission limitation that applies to you. (c) You must also... deviation of an operating limit parameter value, the date, time, and duration of the deviation, a brief...

Moralized Health-Related Persuasion Undermines Social Cohesion

PubMed Central

Täuber, Susanne

2018-01-01

Integrating theory and research on persuasion, moralization, and intergroup relations, the present research aims to highlight the far-reaching impact of health-related persuasion on society. I propose that governments’ health-related persuasion leads to the emergence of new social norms, and in particular moral norms. Importantly, moral norms provide strong behavioral imperatives and are seen as binding for group members. This suggests that moralized persuasion has a strong potential to divide society along the lines of citizens who conform to and citizens who deviate from health-related moral norms. Thus, departing from the traditional focus on targets of persuasion, the present research focuses on those holding a moralized view on health and lifestyle. Key aspects of social cohesion as defined by the OECD (2011) have been tested across four studies. The main hypothesis tested is that those conforming to the norm (e.g., non-smokers, normal weight people, people with healthy lifestyles) will stigmatize those deviating from the norm (e.g., smokers, overweight people, people with unhealthy lifestyles). Flowing from stigmatization, less inclusion, lower solidarity with and greater endorsement of unequal treatment of those deviating from the moral norm are predicted. Four survey studies (total N = 1568) examining the proposed associations among non-smokers, normal weight people, and employees with healthy lifestyles are presented. The studies provide unanimous support for the hypothesis, with meta-analysis providing further support for the reliability of the findings. Consistent across studies, social cohesion indicators were negatively affected by health moralization through stigmatization of those deviating from health-related moral norms. Findings highlight an under-acknowledged potential of moralized health-related persuasion to divide society, thereby undermining cohesion and the achievement of important societal goals. In the discussion, limitations and relevant routes for future research are highlighted. Recommendations are derived for policy makers, institutions, employers, and individuals. PMID:29946279

Magnitude Estimation for Large Earthquakes from Borehole Recordings

NASA Astrophysics Data System (ADS)

Eshaghi, A.; Tiampo, K. F.; Ghofrani, H.; Atkinson, G.

2012-12-01

We present a simple and fast method for magnitude determination technique for earthquake and tsunami early warning systems based on strong ground motion prediction equations (GMPEs) in Japan. This method incorporates borehole strong motion records provided by the Kiban Kyoshin network (KiK-net) stations. We analyzed strong ground motion data from large magnitude earthquakes (5.0 ≤ M ≤ 8.1) with focal depths < 50 km and epicentral distances of up to 400 km from 1996 to 2010. Using both peak ground acceleration (PGA) and peak ground velocity (PGV) we derived GMPEs in Japan. These GMPEs are used as the basis for regional magnitude determination. Predicted magnitudes from PGA values (Mpga) and predicted magnitudes from PGV values (Mpgv) were defined. Mpga and Mpgv strongly correlate with the moment magnitude of the event, provided sufficient records for each event are available. The results show that Mpgv has a smaller standard deviation in comparison to Mpga when compared with the estimated magnitudes and provides a more accurate early assessment of earthquake magnitude. We test this new method to estimate the magnitude of the 2011 Tohoku earthquake and we present the results of this estimation. PGA and PGV from borehole recordings allow us to estimate the magnitude of this event 156 s and 105 s after the earthquake onset, respectively. We demonstrate that the incorporation of borehole strong ground-motion records immediately available after the occurrence of large earthquakes significantly increases the accuracy of earthquake magnitude estimation and the associated improvement in earthquake and tsunami early warning systems performance. Moment magnitude versus predicted magnitude (Mpga and Mpgv).

Non-parametric characterization of long-term rainfall time series

NASA Astrophysics Data System (ADS)

Tiwari, Harinarayan; Pandey, Brij Kishor

2018-03-01

The statistical study of rainfall time series is one of the approaches for efficient hydrological system design. Identifying, and characterizing long-term rainfall time series could aid in improving hydrological systems forecasting. In the present study, eventual statistics was applied for the long-term (1851-2006) rainfall time series under seven meteorological regions of India. Linear trend analysis was carried out using Mann-Kendall test for the observed rainfall series. The observed trend using the above-mentioned approach has been ascertained using the innovative trend analysis method. Innovative trend analysis has been found to be a strong tool to detect the general trend of rainfall time series. Sequential Mann-Kendall test has also been carried out to examine nonlinear trends of the series. The partial sum of cumulative deviation test is also found to be suitable to detect the nonlinear trend. Innovative trend analysis, sequential Mann-Kendall test and partial cumulative deviation test have potential to detect the general as well as nonlinear trend for the rainfall time series. Annual rainfall analysis suggests that the maximum changes in mean rainfall is 11.53% for West Peninsular India, whereas the maximum fall in mean rainfall is 7.8% for the North Mountainous Indian region. The innovative trend analysis method is also capable of finding the number of change point available in the time series. Additionally, we have performed von Neumann ratio test and cumulative deviation test to estimate the departure from homogeneity. Singular spectrum analysis has been applied in this study to evaluate the order of departure from homogeneity in the rainfall time series. Monsoon season (JS) of North Mountainous India and West Peninsular India zones has higher departure from homogeneity and singular spectrum analysis shows the results to be in coherence with the same.

Prediction uncertainty and optimal experimental design for learning dynamical systems.

PubMed

Letham, Benjamin; Letham, Portia A; Rudin, Cynthia; Browne, Edward P

2016-06-01

Dynamical systems are frequently used to model biological systems. When these models are fit to data, it is necessary to ascertain the uncertainty in the model fit. Here, we present prediction deviation, a metric of uncertainty that determines the extent to which observed data have constrained the model's predictions. This is accomplished by solving an optimization problem that searches for a pair of models that each provides a good fit for the observed data, yet has maximally different predictions. We develop a method for estimating a priori the impact that additional experiments would have on the prediction deviation, allowing the experimenter to design a set of experiments that would most reduce uncertainty. We use prediction deviation to assess uncertainty in a model of interferon-alpha inhibition of viral infection, and to select a sequence of experiments that reduces this uncertainty. Finally, we prove a theoretical result which shows that prediction deviation provides bounds on the trajectories of the underlying true model. These results show that prediction deviation is a meaningful metric of uncertainty that can be used for optimal experimental design.

Monodisperse hexagonal silver nanoprisms: synthesis via thiolate-protected cluster precursors and chiral, ligand-imprinted self-assembly.

PubMed

Cathcart, Nicole; Kitaev, Vladimir

2011-09-27

Silver nanoprisms of a predominantly hexagonal shape have been prepared using a ligand combination of a strongly binding thiol, captopril, and charge-stabilizing citrate together with hydrogen peroxide as an oxidative etching agent and a strong base that triggered nanoprism formation. The role of the reagents and their interplay in the nanoprism synthesis is discussed in detail. The beneficial role of chloride ions to attain a high degree of reproducibility and monodispersity of the nanoprisms is elucidated. Control over the nanoprism width, thickness, and, consequently, plasmon resonance in the system has been demonstrated. One of the crucial factors in the nanoprism synthesis was the slow, controlled aggregation of thiolate-stabilized silver nanoclusters as the intermediates. The resulting superior monodispersity (better than ca. 10% standard deviation in lateral size and ca. 15% standard deviation in thickness (<1 nm variation)) and charge stabilization of the produced silver nanoprisms enabled the exploration of the rich diversity of the self-assembled morphologies in the system. Regular columnar assemblies of the self-assembled nanoprisms spanning 2-3 μm in length have been observed. Notably, the helicity of the columnar phases was evident, which can be attributed to the chirality of the strongly binding thiol ligand. Finally, the enhancement of Raman scattering has been observed after oxidative removal of thiolate ligands from the AgNPR surface. © 2011 American Chemical Society

Extreme Right Axis Deviation in Acute Myocardial Infarction: A Hazardous Signal of Poor Prognosis.

PubMed

Wang, Qingyu; Pan, Shuo; Liu, Fuqiang; Yang, Dan; Wang, Jun-Kui

2018-05-11

BACKGROUND New-onset extreme right axis deviation and right bundle branch block (RBBB) are rare during acute myocardial infarction (AMI), and has only been reported in several cases reflecting the severity of AMI. It could predict severe clinical complications and higher risks in coronary artery disease. Although there is little electrophysiological explanation, the complications are severe. They should be emphasized in newly diagnosed extreme right axis deviation and RBBB in AMI. CASE REPORT A 72-year-old male was admitted to our department with a chief complaint of intermittent retrosternal chest pain and was diagnosed with extensive anterior myocardial infarction with RBBB, by elevated myocardial enzymes and ECG. The main wave direction of QRS in lead aVR was positive and showed an extreme right axis deviation. After a month, the patient's chest distress and the RBBB vanished, but a right axis deviation still existed. The echocardiogram showed prior extensive anterior myocardial infarction (including apex myocardia) and lower LVEF. CONCLUSIONS New diagnosed RBBB and right axis deviation is uncommon and could be a useful clue to evaluate myocardial ischemia in AMI cases. This electrocardiographic marker can identify coronary artery occlusion where ST-segments are hard to evaluate, and hence, patients may benefit most from early and complete revascularization strategies such as primary angioplasty.

Do health care workforce, population, and service provision significantly contribute to the total health expenditure? An econometric analysis of Serbia.

PubMed

Santric-Milicevic, M; Vasic, V; Terzic-Supic, Z

2016-08-15

In times of austerity, the availability of econometric health knowledge assists policy-makers in understanding and balancing health expenditure with health care plans within fiscal constraints. The objective of this study is to explore whether the health workforce supply of the public health care sector, population number, and utilization of inpatient care significantly contribute to total health expenditure. The dependent variable is the total health expenditure (THE) in Serbia from the years 2003 to 2011. The independent variables are the number of health workers employed in the public health care sector, population number, and inpatient care discharges per 100 population. The statistical analyses include the quadratic interpolation method, natural logarithm and differentiation, and multiple linear regression analyses. The level of significance is set at P < 0.05. The regression model captures 90 % of all variations of observed dependent variables (adjusted R square), and the model is significant (P < 0.001). Total health expenditure increased by 1.21 standard deviations, with an increase in health workforce growth rate by 1 standard deviation. Furthermore, this rate decreased by 1.12 standard deviations, with an increase in (negative) population growth rate by 1 standard deviation. Finally, the growth rate increased by 0.38 standard deviation, with an increase of the growth rate of inpatient care discharges per 100 population by 1 standard deviation (P < 0.001). Study results demonstrate that the government has been making an effort to control strongly health budget growth. Exploring causality relationships between health expenditure and health workforce is important for countries that are trying to consolidate their public health finances and achieve universal health coverage at the same time.

Variability of Martian Turbopause Altitudes

NASA Astrophysics Data System (ADS)

Slipski, Marek; Jakosky, Bruce; Benna, Mehdi; Mahaffy, Paul R.; Elrod, Meredith K.; Kass, David M.; Gonzalez-Galindo, Francisco

2017-10-01

The transition region between the well-mixed, turbulent lower atmosphere and the diffusive upper atmosphere - the turbopause - is an area of coupled physical processes that can have significant impacts on the structure and dynamics of the mesosphere and thermosphere. Above the turbopause, molecular diffusion dominates and species fractionate according to their masses. Below, turbulence is strong and waves dissipate and break. We have used density measurements from MAVEN's NGIMS instrument and temperatures from MRO's MCS to calculate turbopause altitudes over the course of a Martian year.The homopause, or "mixing-turbopause,” is defined with respect to the mixing ratio of a given atmospheric species. The mean molecular mass of the atmosphere remains essentially constant below, but each species has its own scale height above. We determined this altitude for each MAVEN orbit between Feb 2015 - Dec 2016 by extrapolating the ratio of N2 and 40Ar densities downward to where their ratio equals that measured by Curiosity. To determine the "wave-turbopause" (Offermann et al., 2007) we used variations in monthly-averaged temperature profiles of the upper and lower atmosphere. Because the dissipation of waves produces turbulence the turbopause altitude is set by the transition from strong to weak dissipation. If no energy were lost, the amplitude of a vertically propagating gravity wave would increase exponentially with altitude. Using the monthly standard deviation in temperatures as a proxy for wave amplitude, we show that waves are strongly dissipated at low altitudes but freely propagating in the lower thermosphere. The altitude at which the standard deviation begins to increase substantially from low values at mid-altitudes determines the altitude of the "wave-turbopause."The observed range of turbopause altitudes is 80-140 km. The turbopause is highest during the day and for Ls values near 270°. Homopause altitudes correlate well with changes in CO2 densities. The variation in turbopause altitudes means that energy, mass, and momentum transported vertically are deposited at different altitudes across the planet, which can have a substantial effect on the thermal and dynamical state of the middle-upper atmosphere.

Density Large Deviations for Multidimensional Stochastic Hyperbolic Conservation Laws

NASA Astrophysics Data System (ADS)

Barré, J.; Bernardin, C.; Chetrite, R.

2018-02-01

We investigate the density large deviation function for a multidimensional conservation law in the vanishing viscosity limit, when the probability concentrates on weak solutions of a hyperbolic conservation law. When the mobility and diffusivity matrices are proportional, i.e. an Einstein-like relation is satisfied, the problem has been solved in Bellettini and Mariani (Bull Greek Math Soc 57:31-45, 2010). When this proportionality does not hold, we compute explicitly the large deviation function for a step-like density profile, and we show that the associated optimal current has a non trivial structure. We also derive a lower bound for the large deviation function, valid for a more general weak solution, and leave the general large deviation function upper bound as a conjecture.

Precision analysis for standard deviation measurements of immobile single fluorescent molecule images.

PubMed

DeSantis, Michael C; DeCenzo, Shawn H; Li, Je-Luen; Wang, Y M

2010-03-29

Standard deviation measurements of intensity profiles of stationary single fluorescent molecules are useful for studying axial localization, molecular orientation, and a fluorescence imaging system's spatial resolution. Here we report on the analysis of the precision of standard deviation measurements of intensity profiles of single fluorescent molecules imaged using an EMCCD camera.We have developed an analytical expression for the standard deviation measurement error of a single image which is a function of the total number of detected photons, the background photon noise, and the camera pixel size. The theoretical results agree well with the experimental, simulation, and numerical integration results. Using this expression, we show that single-molecule standard deviation measurements offer nanometer precision for a large range of experimental parameters.

Attenuation relation for strong motion in Eastern Java based on appropriate database and method

NASA Astrophysics Data System (ADS)

Mahendra, Rian; Rohadi, Supriyanto; Rudyanto, Ariska

2017-07-01

The selection and determination of attenuation relation has become important for seismic hazard assessment in active seismic region. This research initially constructs the appropriate strong motion database, including site condition and type of the earthquake. The data set consisted of large number earthquakes of 5 ≤ Mw ≤ 9 and distance less than 500 km that occurred around Java from 2009 until 2016. The location and depth of earthquake are being relocated using double difference method to improve the quality of database. Strong motion data from twelve BMKG's accelerographs which are located in east Java is used. The site condition is known by using dominant period and Vs30. The type of earthquake is classified into crustal earthquake, interface, and intraslab based on slab geometry analysis. A total of 10 Ground Motion Prediction Equations (GMPEs) are tested using Likelihood (Scherbaum et al., 2004) and Euclidean Distance Ranking method (Kale and Akkar, 2012) with the associated database. The evaluation of these methods lead to a set of GMPEs that can be applied for seismic hazard in East Java where the strong motion data is collected. The result of these methods found that there is still high deviation of GMPEs, so the writer modified some GMPEs using inversion method. Validation was performed by analysing the attenuation curve of the selected GMPE and observation data in period 2015 up to 2016. The results show that the selected GMPE is suitable for estimated PGA value in East Java.

Sticky ions in biological systems.

PubMed Central

Collins, K D

1995-01-01

Aqueous gel sieving chromatography on Sephadex G-10 of the Group IA cations (Li+, Na+, K+, Rb+, Cs+) plus NH4+ as the Cl- salts, in combination with previous results for the halide anions (F-, Cl-, Br-, I-) as the Na+ salts [Washabaugh, M.W. & Collins, K.D. (1986) J. Biol. Chem. 261, 12477-12485], leads to the following conclusions. (i) The small monovalent ions (Li+, Na+, F-) flow through the gel with water molecules attached, whereas the large monovalent ions (K+, Rb+, Cs+, Cl-, Br-, I-) adsorb to the nonpolar surface of the gel, a process requiring partial dehydration of the ion and implying that these ions bind the immediately adjacent water molecules weakly. (ii) The transition from strong to weak hydration occurs at a radius of about 1.78 A for the monovalent anions, compared with a radius of about 1.06 A for the monovalent cations (using ionic radii), indicating that the anions are more strongly hydrated than the cations for a given charge density. (iii) The anions show larger deviations from ideal behavior (an elution position corresponding to the anhydrous molecular weight) than do the cations and dominate the chromatographic behavior of the neutral salts. These results are interpreted to mean that weakly hydrated ions (chaotropes) are "pushed" onto weakly hydrated surfaces by strong water-water interactions and that the transition from strong ionic hydration to weak ionic hydration occurs where the strength of ion-water interactions approximately equals the strength of water-water interactions in bulk solution. PMID:7539920

Input clustering in the normal and learned circuits of adult barn owls.

PubMed

McBride, Thomas J; DeBello, William M

2015-05-01

Experience-dependent formation of synaptic input clusters can occur in juvenile brains. Whether this also occurs in adults is largely unknown. We previously reconstructed the normal and learned circuits of prism-adapted barn owls and found that changes in clustering of axo-dendritic contacts (putative synapses) predicted functional circuit strength. Here we asked whether comparable changes occurred in normal and prism-removed adults. Across all anatomical zones, no systematic differences in the primary metrics for within-branch or between-branch clustering were observed: 95-99% of contacts resided within clusters (<10-20 μm from nearest neighbor) regardless of circuit strength. Bouton volumes, a proxy measure of synaptic strength, were on average larger in the functionally strong zones, indicating that changes in synaptic efficacy contributed to the differences in circuit strength. Bootstrap analysis showed that the distribution of inter-contact distances strongly deviated from random not in the functionally strong zones but in those that had been strong during the sensitive period (60-250 d), indicating that clusters formed early in life were preserved regardless of current value. While cluster formation in juveniles appeared to require the production of new synapses, cluster formation in adults did not. In total, these results support a model in which high cluster dynamics in juveniles sculpt a potential connectivity map that is refined in adulthood. We propose that preservation of clusters in functionally weak adult circuits provides a storage mechanism for disused but potentially useful pathways. Copyright © 2015 Elsevier Inc. All rights reserved.

Assessment of the vision-specific quality of life using clustered visual field in glaucoma patients.

PubMed

Sawada, Hideko; Yoshino, Takaiko; Fukuchi, Takeo; Abe, Haruki

2014-02-01

To investigate the significance of vision-specific quality of life (QOL) in glaucoma patients based on the location of visual field defects. We examined 336 eyes of 168 patients. The 25-item National Eye Institute Visual Function Questionnaire was used to evaluate patients' QOL. Visual field testing was performed using the Humphrey Field Analyzer; the visual field was divided into 10 clusters. We defined the eye with better mean deviation as the better eye and the fellow eye as the worse eye. A single linear regression analysis was applied to assess the significance of the relationship between QOL and the clustered visual field. The strongest correlation was observed in the lower paracentral visual field in the better eye. The lower peripheral visual field in the better eye also showed a good correlation. Correlation coefficients in the better eye were generally higher than those in the worse eye. For driving, the upper temporal visual field in the better eye was the most strongly correlated (r=0.509). For role limitation and peripheral vision, the lower peripheral visual field in the better eye had the highest correlation coefficients at 0.459 and 0.425, respectively. Overall, clusters in the lower hemifield in the better eye were more strongly correlated with QOL than those in the worse eye. In particular, the lower paracentral visual field in the better eye was correlated most strongly of all. Driving, however, strongly correlated with the upper hemifield in the better eye.

Family structure and childhood anthropometry in Saint Paul, Minnesota in 1918

PubMed Central

Warren, John Robert

2017-01-01

Concern with childhood nutrition prompted numerous surveys of children’s growth in the United States after 1870. The Children’s Bureau’s 1918 “Weighing and Measuring Test” measured two million children to produce the first official American growth norms. Individual data for 14,000 children survives from the Saint Paul, Minnesota survey whose stature closely approximated national norms. As well as anthropometry the survey recorded exact ages, street address and full name. These variables allow linkage to the 1920 census to obtain demographic and socioeconomic information. We matched 72% of children to census families creating a sample of nearly 10,000 children. Children in the entire survey (linked set) averaged 0.74 (0.72) standard deviations below modern WHO height-for-age standards, and 0.48 (0.46) standard deviations below modern weight-for-age norms. Sibship size strongly influenced height-for-age, and had weaker influence on weight-for-age. Each additional child six or underreduced height-for-age scores by 0.07 standard deviations (95% CI: −0.03, 0.11). Teenage siblings had little effect on height-forage. Social class effects were substantial. Children of laborers averaged half a standard deviation shorter than children of professionals. Family structure and socio-economic status had compounding impacts on children’s stature. PMID:28943749

Dependence of short and intermediate-range order on preparation in experimental and modeled pure a-Si

DOE PAGES

Holmstrom, Eero; Haberl, Bianca; Pakarinen, Olli H.; ...

2016-02-20

Variability in the short-to-intermediate range order of pure amorphous silicon prepared by different experimental and computational techniques is probed by measuring mass density, atomic coordination, bond-angle deviation, and dihedral angle deviation. It is found that there is significant variability in order parameters at these length scales in this archetypal covalently bonded, monoatomic system. This diversity strongly reflects preparation technique and thermal history in both experimental and simulated systems. Experiment and simulation do not fully quantitatively agree, partly due to differences in the way parameters are accessed. However, qualitative agreement in the trends is identified. Relaxed forms of amorphous silicon closelymore » resemble continuous random networks generated by a hybrid method of bond-switching Monte Carlo and molecular dynamics simulation. As-prepared ion implanted amorphous silicon can be adequately modeled using a structure generated from amorphization via ion bombardement using energetic recoils. Preparation methods which narrowly avoid crystallization such as experimental pressure-induced amorphization or simulated melt-quenching result in inhomogeneous structures that contain regions with significant variations in atomic ordering. Ad hoc simulated structures containing small (1 nm) diamond cubic crystal inclusions were found to possess relatively high bond-angle deviations and low dihedral angle deviations, a trend that could not be reconciled with any experimental material.« less

A NEW FACTOR ANALYSIS OF THE SVIB--SUGGESTED MODIFICATION OF EXISTING GROUPS AND IMPLICATIONS FOR COUNSELING.

ERIC Educational Resources Information Center

SMITH, STUART E.; AND OTHERS

FACTOR ANALYSIS WAS CARRIED OUT TO ASCERTAIN THE BEST OCCUPATIONAL GROUP LOCATION FOR EACH OF FOUR STRONG VOCATIONAL INTEREST BLANK (SVIB) SCALES--VETERMINARIAN, SENIOR CPA, PHARMACIST, AND MORTICIAN. THE SVIB WAS ADMINISTERED TO 125 MALE LIBERAL ARTS FRESHMEN. MEANS, STANDARD DEVIATIONS, AND INTERCORRELATIONS WERE COMPUTED. THIS FACTOR ANALYSIS…

Time Perception and Depressive Realism: Judgment Type, Psychophysical Functions and Bias

PubMed Central

Kornbrot, Diana E.; Msetfi, Rachel M.; Grimwood, Melvyn J.

2013-01-01

The effect of mild depression on time estimation and production was investigated. Participants made both magnitude estimation and magnitude production judgments for five time intervals (specified in seconds) from 3 sec to 65 sec. The parameters of the best fitting psychophysical function (power law exponent, intercept, and threshold) were determined individually for each participant in every condition. There were no significant effects of mood (high BDI, low BDI) or judgment (estimation, production) on the mean exponent, n = .98, 95% confidence interval (.96–1.04) or on the threshold. However, the intercept showed a ‘depressive realism’ effect, where high BDI participants had a smaller deviation from accuracy and a smaller difference between estimation and judgment than low BDI participants. Accuracy bias was assessed using three measures of accuracy: difference, defined as psychological time minus physical time, ratio, defined as psychological time divided by physical time, and a new logarithmic accuracy measure defined as ln (ratio). The ln (ratio) measure was shown to have approximately normal residuals when subjected to a mixed ANOVA with mood as a between groups explanatory factor and judgment and time category as repeated measures explanatory factors. The residuals of the other two accuracy measures flagrantly violated normality. The mixed ANOVAs of accuracy also showed a strong depressive realism effect, just like the intercepts of the psychophysical functions. There was also a strong negative correlation between estimation and production judgments. Taken together these findings support a clock model of time estimation, combined with additional cognitive mechanisms to account for the depressive realism effect. The findings also suggest strong methodological recommendations. PMID:23990960

Multiphoton amplitude in a constant background field

NASA Astrophysics Data System (ADS)

Ahmad, Aftab; Ahmadiniaz, Naser; Corradini, Olindo; Kim, Sang Pyo; Schubert, Christian

2018-01-01

In this contribution, we present our recent compact master formulas for the multiphoton amplitudes of a scalar propagator in a constant background field using the worldline fomulation of quantum field theory. The constant field has been included nonperturbatively, which is crucial for strong external fields. A possible application is the scattering of photons by electrons in a strong magnetic field, a process that has been a subject of great interest since the discovery of astrophysical objects like radio pulsars, which provide evidence that magnetic fields of the order of 1012G are present in nature. The presence of a strong external field leads to a strong deviation from the classical scattering amplitudes. We explicitly work out the Compton scattering amplitude in a magnetic field, which is a process of potential relevance for astrophysics. Our final result is compact and suitable for numerical integration.

Asteroseismology of ZZ Ceti stars with full evolutionary white dwarf models. II. The impact of AGB thermal pulses on the asteroseismic inferences of ZZ Ceti stars

NASA Astrophysics Data System (ADS)

De Gerónimo, F. C.; Althaus, L. G.; Córsico, A. H.; Romero, A. D.; Kepler, S. O.

2018-05-01

Context. The thermally pulsing phase on the asymptotic giant branch (TP-AGB) is the last nuclear burning phase experienced by most low- and intermediate-mass stars. During this phase, the outer chemical stratification above the C/O core of the emerging white dwarf (WD) is built up. The chemical structure resulting from progenitor evolution strongly impacts the whole pulsation spectrum exhibited by ZZ Ceti stars, which are pulsating C/O core white dwarfs located on a narrow instability strip at Teff 12 000 K. Several physical processes occurring during progenitor evolution strongly affect the chemical structure of these stars; those found during the TP-AGB phase are the most relevant for the pulsational properties of ZZ Ceti stars. Aims: We present a study of the impact of the chemical structure built up during the TP-AGB evolution on the stellar parameters inferred from asteroseismological fits of ZZ Ceti stars. Methods: Our analysis is based on a set of carbon-oxygen core white dwarf models with masses from 0.534 to 0.6463 M⊙ derived from full evolutionary computations from the ZAMS to the ZZ Ceti domain. We computed evolutionary sequences that experience different number of thermal pulses (TP). Results: We find that the occurrence or not of thermal pulses during AGB evolution implies an average deviation in the asteroseimological effective temperature of ZZ Ceti stars of at most 8% and on the order of ≲5% in the stellar mass. For the mass of the hydrogen envelope, however, we find deviations up to 2 orders of magnitude in the case of cool ZZ Ceti stars. Hot and intermediate temperature ZZ Ceti stars show no differences in the hydrogen envelope mass in most cases. Conclusions: Our results show that, in general, the impact of the occurrence or not of thermal pulses in the progenitor stars is not negligible and must be taken into account in asteroseismological studies of ZZ Ceti stars.

A geometric morphometric analysis of hominin upper second and third molars, with particular emphasis on European Pleistocene populations.

PubMed

Gómez-Robles, Aida; Bermúdez de Castro, José María; Martinón-Torres, María; Prado-Simón, Leyre; Arsuaga, Juan Luis

2012-09-01

The study of dental morphology by means of geometric morphometric methods allows for a detailed and quantitative comparison of hominin species that is useful for taxonomic assignment and phylogenetic reconstruction. Upper second and third molars have been studied in a comprehensive sample of Plio- and Pleistocene hominins from African, Asian and European sites in order to complete our analysis of the upper postcanine dentition. Intraspecific variation in these two molars is high, but some interspecific trends can be identified. Both molars exhibit a strong reduction of the distal cusps in recent hominin species, namely European Homo heidelbergensis, Homo neanderthalensis and Homo sapiens, but this reduction shows specific patterns and proportions in the three groups. Second molars tend to show four well developed cusps in earlier hominin species and their morphology is only marginally affected by allometric effects. Third molars can be incipiently reduced in earlier species and they evince a significant allometric component, identified both inter- and intraspecifically. European Middle Pleistocene fossils from Sima de los Huesos (SH) show a very strong reduction of these two molars, even more marked than the reduction observed in Neanderthals and in modern human populations. The highly derived shape of SH molars points to an early acquisition of typical Neanderthal dental traits by pre-Neanderthal populations and to a deviation of this population from mean morphologies of other European Middle Pleistocene groups. Copyright © 2012 Elsevier Ltd. All rights reserved.

Stimulus discriminability in visual search.

PubMed

Verghese, P; Nakayama, K

1994-09-01

We measured the probability of detecting the target in a visual search task, as a function of the following parameters: the discriminability of the target from the distractors, the duration of the display, and the number of elements in the display. We examined the relation between these parameters at criterion performance (80% correct) to determine if the parameters traded off according to the predictions of a limited capacity model. For the three dimensions that we studied, orientation, color, and spatial frequency, the observed relationship between the parameters deviates significantly from a limited capacity model. The data relating discriminability to display duration are better than predicted over the entire range of orientation and color differences that we examined, and are consistent with the prediction for only a limited range of spatial frequency differences--from 12 to 23%. The relation between discriminability and number varies considerably across the three dimensions and is better than the limited capacity prediction for two of the three dimensions that we studied. Orientation discrimination shows a strong number effect, color discrimination shows almost no effect, and spatial frequency discrimination shows an intermediate effect. The different trading relationships in each dimension are more consistent with early filtering in that dimension, than with a common limited capacity stage. Our results indicate that higher-level processes that group elements together also play a strong role. Our experiments provide little support for limited capacity mechanisms over the range of stimulus differences that we examined in three different dimensions.

Strongly disordered TiN and NbTiN s-wave superconductors probed by microwave electrodynamics.

PubMed

Driessen, E F C; Coumou, P C J J; Tromp, R R; de Visser, P J; Klapwijk, T M

2012-09-07

We probe the effects of strong disorder (2.4

Analysis of using the tongue deviation angle as a warning sign of a stroke

PubMed Central

2012-01-01

Background The symptom of tongue deviation is observed in a stroke or transient ischemic attack. Nevertheless, there is much room for the interpretation of the tongue deviation test. The crucial factor is the lack of an effective quantification method of tongue deviation. If we can quantify the features of the tongue deviation and scientifically verify the relationship between the deviation angle and a stroke, the information provided by the tongue will be helpful in recognizing a warning of a stroke. Methods In this study, a quantification method of the tongue deviation angle was proposed for the first time to characterize stroke patients. We captured the tongue images of stroke patients (15 males and 10 females, ranging between 55 and 82 years of age); transient ischemic attack (TIA) patients (16 males and 9 females, ranging between 53 and 79 years of age); and normal subjects (14 males and 11 females, ranging between 52 and 80 years of age) to analyze whether the method is effective. In addition, we used the receiver operating characteristic curve (ROC) for the sensitivity analysis, and determined the threshold value of the tongue deviation angle for the warning sign of a stroke. Results The means and standard deviations of the tongue deviation angles of the stroke, TIA, and normal groups were: 6.9 ± 3.1, 4.9 ± 2.1 and 1.4 ± 0.8 degrees, respectively. Analyzed by the unpaired Student’s t-test, the p-value between the stroke group and the TIA group was 0.015 (>0.01), indicating no significant difference in the tongue deviation angle. The p-values between the stroke group and the normal group, as well as between the TIA group and the normal group were both less than 0.01. These results show the significant differences in the tongue deviation angle between the patient groups (stroke and TIA patients) and the normal group. These results also imply that the tongue deviation angle can effectively identify the patient group (stroke and TIA patients) and the normal group. With respect to the visual examination, 40% and 32% of stroke patients, 24% and 16% of TIA patients, and 4% and 0% of normal subjects were found to have tongue deviations when physicians “A” and “B” examined them. The variation showed the essentiality of the quantification method in a clinical setting. In the receiver operating characteristic curve (ROC), the Area Under Curve (AUC, = 0.96) indicates good discrimination. The tongue deviation angle more than the optimum threshold value (= 3.2°) predicts a risk of stroke. Conclusions In summary, we developed an effective quantification method to characterize the tongue deviation angle, and we confirmed the feasibility of recognizing the tongue deviation angle as an early warning sign of an impending stroke. PMID:22908956

Analysis of using the tongue deviation angle as a warning sign of a stroke.

PubMed

Wei, Ching-Chuan; Huang, Shu-Wen; Hsu, Sheng-Lin; Chen, Hsing-Chung; Chen, Jong-Shin; Liang, Hsinying

2012-08-21

The symptom of tongue deviation is observed in a stroke or transient ischemic attack. Nevertheless, there is much room for the interpretation of the tongue deviation test. The crucial factor is the lack of an effective quantification method of tongue deviation. If we can quantify the features of the tongue deviation and scientifically verify the relationship between the deviation angle and a stroke, the information provided by the tongue will be helpful in recognizing a warning of a stroke. In this study, a quantification method of the tongue deviation angle was proposed for the first time to characterize stroke patients. We captured the tongue images of stroke patients (15 males and 10 females, ranging between 55 and 82 years of age); transient ischemic attack (TIA) patients (16 males and 9 females, ranging between 53 and 79 years of age); and normal subjects (14 males and 11 females, ranging between 52 and 80 years of age) to analyze whether the method is effective. In addition, we used the receiver operating characteristic curve (ROC) for the sensitivity analysis, and determined the threshold value of the tongue deviation angle for the warning sign of a stroke. The means and standard deviations of the tongue deviation angles of the stroke, TIA, and normal groups were: 6.9 ± 3.1, 4.9 ± 2.1 and 1.4 ± 0.8 degrees, respectively. Analyzed by the unpaired Student's t-test, the p-value between the stroke group and the TIA group was 0.015 (>0.01), indicating no significant difference in the tongue deviation angle. The p-values between the stroke group and the normal group, as well as between the TIA group and the normal group were both less than 0.01. These results show the significant differences in the tongue deviation angle between the patient groups (stroke and TIA patients) and the normal group. These results also imply that the tongue deviation angle can effectively identify the patient group (stroke and TIA patients) and the normal group. With respect to the visual examination, 40% and 32% of stroke patients, 24% and 16% of TIA patients, and 4% and 0% of normal subjects were found to have tongue deviations when physicians "A" and "B" examined them. The variation showed the essentiality of the quantification method in a clinical setting. In the receiver operating characteristic curve (ROC), the Area Under Curve (AUC, = 0.96) indicates good discrimination. The tongue deviation angle more than the optimum threshold value (= 3.2°) predicts a risk of stroke. In summary, we developed an effective quantification method to characterize the tongue deviation angle, and we confirmed the feasibility of recognizing the tongue deviation angle as an early warning sign of an impending stroke.

Universal properties of knotted polymer rings.

PubMed

Baiesi, M; Orlandini, E

2012-09-01

By performing Monte Carlo sampling of N-steps self-avoiding polygons embedded on different Bravais lattices we explore the robustness of universality in the entropic, metric, and geometrical properties of knotted polymer rings. In particular, by simulating polygons with N up to 10(5) we furnish a sharp estimate of the asymptotic values of the knot probability ratios and show their independence on the lattice type. This universal feature was previously suggested, although with different estimates of the asymptotic values. In addition, we show that the scaling behavior of the mean-squared radius of gyration of polygons depends on their knot type only through its correction to scaling. Finally, as a measure of the geometrical self-entanglement of the self-avoiding polygons we consider the standard deviation of the writhe distribution and estimate its power-law behavior in the large N limit. The estimates of the power exponent do depend neither on the lattice nor on the knot type, strongly supporting an extension of the universality property to some features of the geometrical entanglement.

Viscoelastic properties of PLA/PCL blends compatibilized with different methods

NASA Astrophysics Data System (ADS)

Shin, Boo Young; Han, Do Hung

2017-11-01

The aim of this study was to observe changes in the viscoelastic properties of PLA/PCL (80/20) blends produced using different compatibilization methods. Reactive extrusion and high-energy radiation methods were used for blend compatibilization. Storage and loss moduli, complex viscosity, transient stress relaxation modulus, and tan δ of blends were analyzed and blend morphologies were examined. All compatibilized PLA/PCL blends had smaller dispersed particle sizes than the non-compatibilized blend, and well compatibilized blends had finer morphologies than poorly compatibilized blends. Viscoelastic properties differentiated well compatibilized and poorly compatibilized blends. Well compatibilized blends had higher storage and loss moduli and complex viscosities than those calculated by the log-additive mixing rule due to strong interfacial adhesion, whereas poorly compatibilized blends showed negative deviations due to weak interfacial adhesion. Moreover, well compatibilized blends had much slower stress relaxation than poorly compatibilized blends and didn't show tan δ plateau region caused by slippage at the interface between continuous and dispersed phases.

Elastic Instability of Slender Rods in Steady Shear Flow Yields Positive First Normal Stress Differences

NASA Astrophysics Data System (ADS)

Becker, Leif E.; Shelley, Michael J.

2000-11-01

First normal stress differences in shear flow are a fundamental property of Non-Newtonian fluids. Experiments involving dilute suspensions of slender fibers exhibit a sharp transition to non-zero normal stress differences beyond a critical shear rate, but existing continuum theories for rigid rods predict neither this transition nor the corresponding magnitude of this effect. We present the first conclusive evidence that elastic instabilities are predominantly responsible for observed deviations from the dilute suspension theory of rigid rods. Our analysis is based on slender body theory and the equilibrium equations of elastica. A straight slender body executing its Jeffery orbit in Couette flow is subject to axial fluid forcing, alternating between compression and tension. We present a stability analysis showing that elastic instabilities are possible for strong flows. Simulations give the fully non-linear evolution of this shape instability, and show that flexibility of the fibers alone is sufficient to cause both shear-thinning and significant first normal stress differences.

Indo-Pacific sea level variability during recent decades

NASA Astrophysics Data System (ADS)

Yamanaka, G.; Tsujino, H.; Nakano, H.; Urakawa, S. L.; Sakamoto, K.

2016-12-01

Decadal variability of sea level in the Indo-Pacific region is investigated using a historical OGCM simulation. The OGCM driven by the atmospheric forcing removing long-term trends clearly exhibits decadal sea level variability in the Pacific Ocean, which is associated with eastern tropical Pacific thermal anomalies. During the period of 1977-1987, the sea level anomalies are positive in the eastern equatorial Pacific and show deviations from a north-south symmetric distribution, with strongly negative anomalies in the western tropical South Pacific. During the period of 1996-2006, in contrast, the sea level anomalies are negative in the eastern equatorial Pacific and show a nearly north-south symmetric pattern, with positive anomalies in both hemispheres. Concurrently, sea level anomalies in the south-eastern Indian Ocean vary with those in the western tropical Pacific. These sea level variations are closely related to large-scale wind fields. Indo-Pacific sea level distributions are basically determined by wind anomalies over the equatorial region as well as wind stress curl anomalies over the off-equatorial region.

Correlation between length and tilt of lipid tails

NASA Astrophysics Data System (ADS)

Kopelevich, Dmitry I.; Nagle, John F.

2015-10-01

It is becoming recognized from simulations, and to a lesser extent from experiment, that the classical Helfrich-Canham membrane continuum mechanics model can be fruitfully enriched by the inclusion of molecular tilt, even in the fluid, chain disordered, biologically relevant phase of lipid bilayers. Enriched continuum theories then add a tilt modulus κθ to accompany the well recognized bending modulus κ. Different enrichment theories largely agree for many properties, but it has been noticed that there is considerable disagreement in one prediction; one theory postulates that the average length of the hydrocarbon chain tails increases strongly with increasing tilt and another predicts no increase. Our analysis of an all-atom simulation favors the latter theory, but it also shows that the overall tail length decreases slightly with increasing tilt. We show that this deviation from continuum theory can be reconciled by consideration of the average shape of the tails, which is a descriptor not obviously includable in continuum theory.

Methodenvergleich zur Bestimmung der hydraulischen Durchlässigkeit

NASA Astrophysics Data System (ADS)

Storz, Katharina; Steger, Hagen; Wagner, Valentin; Bayer, Peter; Blum, Philipp

2017-06-01

Knowing the hydraulic conductivity (K) is a precondition for understanding groundwater flow processes in the subsurface. Numerous laboratory and field methods for the determination of hydraulic conductivity exist, which can lead to significantly different results. In order to quantify the variability of these various methods, the hydraulic conductivity was examined for an industrial silica sand (Dorsilit) using four different methods: (1) grain-size analysis, (2) Kozeny-Carman approach, (3) permeameter tests and (4) flow rate experiments in large-scale tank experiments. Due to the large volume of the artificially built aquifer, the tank experiment results are assumed to be the most representative. Hydraulic conductivity values derived from permeameter tests show only minor deviation, while results of the empirically evaluated grain-size analysis are about one magnitude higher and show great variances. The latter was confirmed by the analysis of several methods for the determination of K-values found in the literature, thus we generally question the suitability of grain-size analyses and strongly recommend the use of permeameter tests.

Heat flux modeling using ion drift effects in DIII-D H-mode plasmas with resonant magnetic perturbations

DOE PAGES

Wingen, Andreas; Schmitz, Oliver; Evans, Todd E.; ...

2014-01-01

The heat flux patterns measured in low-collisionality DIII-D H-mode plasmas strongly deviate from simultaneously measured CII emission patterns, used as indicator of particle flux, during applied resonant magnetic perturbations. While the CII emission clearly shows typical striations, which are similar to magnetic footprint patterns obtained from vacuum field line tracing, the heat flux is usually dominated by one large peak at the strike point position. The vacuum approximation, which only considers applied magnetic fields and neglects plasma response and plasma effects, cannot explain the shape of the observed heat flux pattern. One possible explanation is the effect of particle drifts.more » This is included in the field line equations and the results are discussed with reference to the measurement. Electrons and ions show di fferent drift motions at thermal energy levels in a guiding center approximation. While electrons hardly deviate from the field lines, ions can drift several centimetres away from field line flux surfaces. A model is presented in which an ion heat flux, based on the ion drift motion from various kinetic energies as they contribute to a thermal Maxwellian distribution, is calculated. The simulated heat flux is directly compared to measurements with a varying edge safety factor q95. This analysis provides evidence for the dominate e ect of high-energy ions in carrying heat from the plasma inside the separatrix to the target. High-energy ions are deposited close to the unperturbed strike line while low-energy ions can travel into the striated magnetic topology.« less

Accounting for body size deviations when reporting bone mineral density variables in children.

PubMed

Webber, C E; Sala, A; Barr, R D

2009-01-01

In a child, bone mineral density (BMD) may differ from an age-expected normal value, not only because of the presence of disease, but also because of deviations of height or weight from population averages. Appropriate adjustment for body size deviations simplifies interpretation of BMD measurements. For children, a bone mineral density (BMD) measurement is normally expressed as a Z score. Interpretation is complicated when weight or height distinctly differ from age-matched children. We develop a procedure to allow for the influence of body size deviations upon measured BMD. We examined the relation between body size deviation and spine, hip and whole body BMD deviation in 179 normal children (91 girls). Expressions were developed that allowed derivation of an expected BMD based on age, gender and body size deviation. The difference between measured and expected BMD was expressed as a HAW score (Height-, Age-, Weight-adjusted score). In a second independent sample of 26 normal children (14 girls), measured spine, total femur and whole body BMD all fell within the same single normal range after accounting for age, gender and body size deviations. When traditional Z scores and HAW scores were compared in 154 children, 17.5% showed differences of more than 1 unit and such differences were associated with height and weight deviations. For almost 1 in 5 children, body size deviations influence BMD to an extent that could alter clinical management.

Percentage depth dose calculation accuracy of model based algorithms in high energy photon small fields through heterogeneous media and comparison with plastic scintillator dosimetry.

PubMed

Alagar, Ananda Giri Babu; Mani, Ganesh Kadirampatti; Karunakaran, Kaviarasu

2016-01-08

Small fields smaller than 4 × 4 cm2 are used in stereotactic and conformal treatments where heterogeneity is normally present. Since dose calculation accuracy in both small fields and heterogeneity often involves more discrepancy, algorithms used by treatment planning systems (TPS) should be evaluated for achieving better treatment results. This report aims at evaluating accuracy of four model-based algorithms, X-ray Voxel Monte Carlo (XVMC) from Monaco, Superposition (SP) from CMS-Xio, AcurosXB (AXB) and analytical anisotropic algorithm (AAA) from Eclipse are tested against the measurement. Measurements are done using Exradin W1 plastic scintillator in Solid Water phantom with heterogeneities like air, lung, bone, and aluminum, irradiated with 6 and 15 MV photons of square field size ranging from 1 to 4 cm2. Each heterogeneity is introduced individually at two different depths from depth-of-dose maximum (Dmax), one setup being nearer and another farther from the Dmax. The central axis percentage depth-dose (CADD) curve for each setup is measured separately and compared with the TPS algorithm calculated for the same setup. The percentage normalized root mean squared deviation (%NRMSD) is calculated, which represents the whole CADD curve's deviation against the measured. It is found that for air and lung heterogeneity, for both 6 and 15 MV, all algorithms show maximum deviation for field size 1 × 1 cm2 and gradually reduce when field size increases, except for AAA. For aluminum and bone, all algorithms' deviations are less for 15 MV irrespective of setup. In all heterogeneity setups, 1 × 1 cm2 field showed maximum deviation, except in 6MV bone setup. All algorithms in the study, irrespective of energy and field size, when any heterogeneity is nearer to Dmax, the dose deviation is higher compared to the same heterogeneity far from the Dmax. Also, all algorithms show maximum deviation in lower-density materials compared to high-density materials.

Static Scene Statistical Non-Uniformity Correction

DTIC Science & Technology

2015-03-01

Error NUC Non-Uniformity Correction RMSE Root Mean Squared Error RSD Relative Standard Deviation S3NUC Static Scene Statistical Non-Uniformity...Deviation ( RSD ) which normalizes the standard deviation, σ, to the mean estimated value, µ using the equation RS D = σ µ × 100. The RSD plot of the gain...estimates is shown in Figure 4.1(b). The RSD plot shows that after a sample size of approximately 10, the different photocount values and the inclusion

Predictions of glass transition temperature for hydrogen bonding biomaterials.

PubMed

van der Sman, R G M

2013-12-19

We show that the glass transition of a multitude of mixtures containing hydrogen bonding materials correlates strongly with the effective number of hydroxyl groups per molecule, which are available for intermolecular hydrogen bonding. This correlation is in compliance with the topological constraint theory, wherein the intermolecular hydrogen bonds constrain the mobility of the hydrogen bonded network. The finding that the glass transition relates to hydrogen bonding rather than free volume agrees with our recent finding that there is little difference in free volume among carbohydrates and polysaccharides. For binary and ternary mixtures of sugars, polyols, or biopolymers with water, our correlation states that the glass transition temperature is linear with the inverse of the number of effective hydroxyl groups per molecule. Only for dry biopolymer/sugar or sugar/polyol mixtures do we find deviations due to nonideal mixing, imposed by microheterogeneity.

Ion transport mechanism in glasses: non-Arrhenius conductivity and nonuniversal features.

PubMed

Murugavel, S; Vaid, C; Bhadram, V S; Narayana, C

2010-10-28

In this article, we report non-Arrhenius behavior in the temperature-dependent dc conductivity of alkali ion conducting silicate glasses well below their glass transition temperature. In contrast to the several fast ion-conducting and binary potassium silicate glasses, these glasses show a positive deviation in the Arrhenius plot. The observed non-Arrhenius behavior is completely reproducible in nature even after prolonged annealing close to the glass transition temperature of the respective glass sample. These results are the manifestation of local structural changes of the silicate network with temperature and give rise to different local environments into which the alkali ions hop, revealed by in situ high-temperature Raman spectroscopy. Furthermore, the present study provides new insights into the strong link between the dynamics of the alkali ions and different sites associated with it in the glasses.

Free-space to few-mode-fiber coupling under atmospheric turbulence.

PubMed

Zheng, Donghao; Li, Yan; Chen, Erhu; Li, Beibei; Kong, Deming; Li, Wei; Wu, Jian

2016-08-08

High speed free space optical communication (FSOC) has taken advantages of components developed for fiber-optic communication systems. Recently, with the rapid development of few-mode-fiber based fiber communication systems, few-mode-fiber components might further promote their applications in FSOC system. The coupling efficiency between free space optical beam and few-mode fibers under atmospheric turbulence effect are investigated in this paper. Both simulation and experimental results show that, compared with single-mode fiber, the coupling efficiencies for a 2-mode fiber and a 4-mode fiber are improved by ~4 dB and ~7 dB respectively in the presence of medium moderate and strong turbulence. Compared with single-mode fiber, the relative standard deviation of received power is restrained by 51% and 66% respectively with a 4-mode and 2-mode fiber.

Spatiotemporal Self-Organization of Fluctuating Bacterial Colonies

NASA Astrophysics Data System (ADS)

Grafke, Tobias; Cates, Michael E.; Vanden-Eijnden, Eric

2017-11-01

We model an enclosed system of bacteria, whose motility-induced phase separation is coupled to slow population dynamics. Without noise, the system shows both static phase separation and a limit cycle, in which a rising global population causes a dense bacterial colony to form, which then declines by local cell death, before dispersing to reinitiate the cycle. Adding fluctuations, we find that static colonies are now metastable, moving between spatial locations via rare and strongly nonequilibrium pathways, whereas the limit cycle becomes almost periodic such that after each redispersion event the next colony forms in a random location. These results, which hint at some aspects of the biofilm-planktonic life cycle, can be explained by combining tools from large deviation theory with a bifurcation analysis in which the global population density plays the role of control parameter.

Testing violation of the Leggett-Garg-type inequality in neutrino oscillations of the Daya Bay experiment

NASA Astrophysics Data System (ADS)

Fu, Qiang; Chen, Xurong

2017-11-01

The Leggett-Garg inequality (LGI), derived under the assumption of realism, acts as the temporal Bell inequality. It is studied in electromagnetic and strong interaction like photonics, superconducting qubits and nuclear spin. The weak interaction two-state oscillations of neutrinos affirmed the violation of Leggett-Garg-type inequalities (LGtI). We make an empirical test for the deviation of experimental results with the classical limits by analyzing the survival probability data of reactor neutrinos at a distinct range of baseline dividing energies, as an analog to a single neutrino detected at different times. A study of the updated data of the Daya Bay experiment unambiguously depicts an obvious cluster of data over the classical bound of LGtI and shows a 6.1σ significance of the violation of them.

Hierarchical quantum master equation approach to electronic-vibrational coupling in nonequilibrium transport through nanosystems

NASA Astrophysics Data System (ADS)

Schinabeck, C.; Erpenbeck, A.; Härtle, R.; Thoss, M.

2016-11-01

Within the hierarchical quantum master equation (HQME) framework, an approach is presented, which allows a numerically exact description of nonequilibrium charge transport in nanosystems with strong electronic-vibrational coupling. The method is applied to a generic model of vibrationally coupled transport considering a broad spectrum of parameters ranging from the nonadiabatic to the adiabatic regime and including both resonant and off-resonant transport. We show that nonequilibrium effects are important in all these regimes. In particular, in the off-resonant transport regime, the inelastic cotunneling signal is analyzed for a vibrational mode in full nonequilibrium, revealing a complex interplay of different transport processes and deviations from the commonly used G0/2 rule of thumb. In addition, the HQME approach is used to benchmark approximate master equation and nonequilibrium Green's function methods.

Appplications of the post-Tolman-Oppenheimer-Volkoff formalism

NASA Astrophysics Data System (ADS)

Silva, Hector O.; Glampedakis, Kostas; Pappas, George; Berti, Emanuele

2017-01-01

Besides their astrophysical interest, neutron stars are promising candidates for testing theories of gravity in the strong-field regime. It is known that, generically, modifications to general relativity affect the bulk properties of neutron stars, e.g. their masses and radii, in a way that depends on the specific choice of theory. In this presentation we review a theory-agnostic approach to model relativistic stars, called the post-Tolman-Oppenheimer-Volkoff formalism. Drawing inspiration from the parametrized post-Newtonian formalism, this framework allows us to describe perturbative deviations from general relativity in the structure of neutrons stars in a parametrized manner. We show that a variety of astrophysical observables (namely the surface redshift, the apparent radius, the Eddington luminosity and the orbital frequency of particles in geodesic motion around neutron stars) can be parametrized using only two parameters.

The legacy of disadvantage: multigenerational neighborhood effects on cognitive ability.

PubMed

Sharkey, Patrick; Elwert, Felix

2011-05-01

This study examines how the neighborhood environments experienced over multiple generations of a family influence children's cognitive ability. Building on recent research showing strong continuity in neighborhood environments across generations of family members, the authors argue for a revised perspective on "neighborhood effects" that considers the ways in which the neighborhood environment in one generation may have a lingering impact on the next generation. To analyze multigenerational effects, the authors use newly developed methods designed to estimate unbiased treatment effects when treatments and confounders vary over time. The results confirm a powerful link between neighborhoods and cognitive ability that extends across generations. A family's exposure to neighborhood poverty across two consecutive generations reduces child cognitive ability by more than half a standard deviation. A formal sensitivity analysis suggests that results are robust to unobserved selection bias.

Quantitative FLASH MRI at 3T using a rational approximation of the Ernst equation.

PubMed

Helms, Gunther; Dathe, Henning; Dechent, Peter

2008-03-01

From the half-angle substitution of trigonometric terms in the Ernst equation, rational approximations of the flip angle dependence of the FLASH signal can be derived. Even the rational function of the lowest order was in good agreement with the experiment for flip angles up to 20 degrees . Three-dimensional maps of the signal amplitude and longitudinal relaxation rates in human brain were obtained from eight subjects by dual-angle measurements at 3T (nonselective 3D-FLASH, 7 degrees and 20 degrees flip angle, TR = 30 ms, isotropic resolution of 0.95 mm, each 7:09 min). The corresponding estimates of T1 and signal amplitude are simple algebraic expressions and deviated about 1% from the exact solution. They are ill-conditioned to estimate the local flip angle deviation but can be corrected post hoc by division of squared RF maps obtained by independent measurements. Local deviations from the nominal flip angles strongly affected the relaxation estimates and caused considerable blurring of the T1 histograms. (c) 2008 Wiley-Liss, Inc.

Post-Kerr black hole spectroscopy

NASA Astrophysics Data System (ADS)

Glampedakis, Kostas; Pappas, George; Silva, Hector O.; Berti, Emanuele

2017-09-01

One of the central goals of the newborn field of gravitational wave astronomy is to test gravity in the highly nonlinear, strong field regime characterizing the spacetime of black holes. In particular, "black hole spectroscopy" (the observation and identification of black hole quasinormal mode frequencies in the gravitational wave signal) is expected to become one of the main tools for probing the structure and dynamics of Kerr black holes. In this paper we take a significant step toward that goal by constructing a "post-Kerr" quasinormal mode formalism. The formalism incorporates a parametrized but general perturbative deviation from the Kerr metric and exploits the well-established connection between the properties of the spacetime's circular null geodesics and the fundamental quasinormal mode to provide approximate, eikonal limit formulas for the modes' complex frequencies. The resulting algebraic toolkit can be used in waveform templates for ringing black holes with the purpose of measuring deviations from the Kerr metric. As a first illustrative application of our framework, we consider the Johannsen-Psaltis deformed Kerr metric and compute the resulting deviation in the quasinormal mode frequency relative to the known Kerr result.

Quantification of the first-order high-pass filter's influence on the automatic measurements of the electrocardiogram.

PubMed

Isaksen, Jonas; Leber, Remo; Schmid, Ramun; Schmid, Hans-Jakob; Generali, Gianluca; Abächerli, Roger

2017-02-01

The first-order high-pass filter (AC coupling) has previously been shown to affect the ECG for higher cut-off frequencies. We seek to find a systematic deviation in computer measurements of the electrocardiogram when the AC coupling with a 0.05 Hz first-order high-pass filter is used. The standard 12-lead electrocardiogram from 1248 patients and the automated measurements of their DC and AC coupled version were used. We expect a large unipolar QRS-complex to produce a deviation in the opposite direction in the ST-segment. We found a strong correlation between the QRS integral and the offset throughout the ST-segment. The coefficient for J amplitude deviation was found to be -0.277 µV/(µV⋅s). Potential dangerous alterations to the diagnostically important ST-segment were found. Medical professionals and software developers for electrocardiogram interpretation programs should be aware of such high-pass filter effects since they could be misinterpreted as pathophysiology or some pathophysiology could be masked by these effects. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Diameter effect on stress-wave evaluation of modulus of elasticity of logs

Treesearch

Xiping Wang; Robert J. Ross; Brian K. Brashaw; John Punches; John R. Erickson; John W. Forsman; Roy E. Pellerin

2004-01-01

Recent studies on nondestructive evaluation (NDE) of logs have shown that a longitudinal stress-wave method can be used to nondestructively evaluate the modulus of elasticity (MOE) of logs. A strong relationship has been found between stress-wave MOE and static MOE of logs, but a significant deviation was observed between stress-wave and static values. The objective of...

Diameter effect on stress-wave evaluation of modulus of elasticity of logs

Treesearch

Xiping Wang; Robert J. Ross; Brian K. Brashaw; John R. Erickson; John W. Forsman; Roy Pellerin

2003-01-01

Recent studies on nondestructive evaluation (NDE) of logs have shown that a longitudinal stress-wave method can be used to nondestructively evaluate the modulus of elasticity (MOE) of logs. A strong relationship has been found between stress-wave MOE and static MOE of logs, but a significant deviation was observed between stress-wave and static values. The objective of...

"Chemical contraction" in rubidium-bismuth melts

NASA Astrophysics Data System (ADS)

Khairulin, R. A.; Abdullaev, R. N.; Stankus, S. V.

2017-10-01

The density and thermal expansion of liquid rubidium and rubidium-bismuth alloy containing 25.0 at % Bi were measured by the gamma-ray attenuation technique at temperatures from liquidus to 1000 K. The results of this study were compared with the data obtained by other authors. The molar volume of the Rb75Bi25 melt strongly deviates from the additivity rule for ideal solutions.

Dynamics-Enabled Nanoelectromechanical Systems (NEMS) Oscillators

DTIC Science & Technology

2014-06-01

it becomes strongly nonlinear, and thus constitutes an archetypal candidate for nonlinear engineering • its fundamental resonant frequency...width of spectral peaks of atomic force microscopy (AFM) resonators as they are brought close to a surface. 39 Approved for public release...alternating current AD Allan Deviation AFM atomic force microscopy AFRL Air Force Research Laboratory AlN aluminum nitride APN Anomalous Phase

The Mott transition in the strong coupling perturbation theory

NASA Astrophysics Data System (ADS)

Sherman, A.

2015-01-01

Using the strong coupling diagram technique a self-consistent equation for the electron Green's function is derived for the repulsive Hubbard model. Terms of two lowest orders of the ratio of the bandwidth Δ to the Hubbard repulsion U are taken into account in the irreducible part of the Larkin equation. The obtained equation is shown to retain causality and reduces to Green's function of uncorrelated electrons in the limit U → 0. Calculations were performed for the semi-elliptical initial band. It is shown that the approximation describes the Mott transition, which occurs at Uc =√{ 3 } Δ / 2. This value coincides with that obtained in the Hubbard-III approximation. At half-filling, for 0 < U Uc the Mott gap disappears.

Simultaneous Validation of Seven Physical Activity Questionnaires Used in Japanese Cohorts for Estimating Energy Expenditure: A Doubly Labeled Water Study.

PubMed

Sasai, Hiroyuki; Nakata, Yoshio; Murakami, Haruka; Kawakami, Ryoko; Nakae, Satoshi; Tanaka, Shigeho; Ishikawa-Takata, Kazuko; Yamada, Yosuke; Miyachi, Motohiko

2018-04-28

Physical activity questionnaires (PAQs) used in large-scale Japanese cohorts have rarely been simultaneously validated against the gold standard doubly labeled water (DLW) method. This study examined the validity of seven PAQs used in Japan for estimating energy expenditure against the DLW method. Twenty healthy Japanese adults (9 men; mean age, 32.4 [standard deviation {SD}, 9.4] years, mainly researchers and students) participated in this study. Fifteen-day daily total energy expenditure (TEE) and basal metabolic rate (BMR) were measured using the DLW method and a metabolic chamber, respectively. Activity energy expenditure (AEE) was calculated as TEE - BMR - 0.1 × TEE. Seven PAQs were self-administered to estimate TEE and AEE. The mean measured values of TEE and AEE were 2,294 (SD, 318) kcal/day and 721 (SD, 161) kcal/day, respectively. All of the PAQs indicated moderate-to-strong correlations with the DLW method in TEE (rho = 0.57-0.84). Two PAQs (Japan Public Health Center Study [JPHC]-PAQ Short and JPHC-PAQ Long) showed significant equivalence in TEE and moderate intra-class correlation coefficients (ICC). None of the PAQs showed significantly equivalent AEE estimates, with differences ranging from -547 to 77 kcal/day. Correlations and ICCs in AEE were mostly weak or fair (rho = 0.02-0.54, and ICC = 0.00-0.44). Only JPHC-PAQ Short provided significant and fair agreement with the DLW method. TEE estimated by the PAQs showed moderate or strong correlations with the results of DLW. Two PAQs showed equivalent TEE and moderate agreement. None of the PAQs showed equivalent AEE estimation to the gold standard, with weak-to-fair correlations and agreements. Further studies with larger sample sizes are needed to confirm these findings.

Experimental and Numerical Evaluation of the Mechanical Behavior of Strongly Anisotropic Light-Weight Metallic Fiber Structures under Static and Dynamic Compressive Loading

PubMed Central

Andersen, Olaf; Vesenjak, Matej; Fiedler, Thomas; Jehring, Ulrike; Krstulović-Opara, Lovre

2016-01-01

Rigid metallic fiber structures made from a variety of different metals and alloys have been investigated mainly with regard to their functional properties such as heat transfer, pressure drop, or filtration characteristics. With the recent advent of aluminum and magnesium-based fiber structures, the application of such structures in light-weight crash absorbers has become conceivable. The present paper therefore elucidates the mechanical behavior of rigid sintered fiber structures under quasi-static and dynamic loading. Special attention is paid to the strongly anisotropic properties observed for different directions of loading in relation to the main fiber orientation. Basically, the structures show an orthotropic behavior; however, a finite thickness of the fiber slabs results in moderate deviations from a purely orthotropic behavior. The morphology of the tested specimens is examined by computed tomography, and experimental results for different directions of loading as well as different relative densities are presented. Numerical calculations were carried out using real structural data derived from the computed tomography data. Depending on the direction of loading, the fiber structures show a distinctively different deformation behavior both experimentally and numerically. Based on these results, the prevalent modes of deformation are discussed and a first comparison with an established polymer foam and an assessment of the applicability of aluminum fiber structures in crash protection devices is attempted. PMID:28773522

Experimental and Numerical Evaluation of the Mechanical Behavior of Strongly Anisotropic Light-Weight Metallic Fiber Structures under Static and Dynamic Compressive Loading.

PubMed

Andersen, Olaf; Vesenjak, Matej; Fiedler, Thomas; Jehring, Ulrike; Krstulović-Opara, Lovre

2016-05-21

Rigid metallic fiber structures made from a variety of different metals and alloys have been investigated mainly with regard to their functional properties such as heat transfer, pressure drop, or filtration characteristics. With the recent advent of aluminum and magnesium-based fiber structures, the application of such structures in light-weight crash absorbers has become conceivable. The present paper therefore elucidates the mechanical behavior of rigid sintered fiber structures under quasi-static and dynamic loading. Special attention is paid to the strongly anisotropic properties observed for different directions of loading in relation to the main fiber orientation. Basically, the structures show an orthotropic behavior; however, a finite thickness of the fiber slabs results in moderate deviations from a purely orthotropic behavior. The morphology of the tested specimens is examined by computed tomography, and experimental results for different directions of loading as well as different relative densities are presented. Numerical calculations were carried out using real structural data derived from the computed tomography data. Depending on the direction of loading, the fiber structures show a distinctively different deformation behavior both experimentally and numerically. Based on these results, the prevalent modes of deformation are discussed and a first comparison with an established polymer foam and an assessment of the applicability of aluminum fiber structures in crash protection devices is attempted.

Interfacial Coupling and Electronic Structure of Two-Dimensional Silicon Grown on the Ag(111) Surface at High Temperature

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

Feng, Jiagui; Wagner, Sean R.; Zhang, Pengpeng

Freestanding silicene, a monolayer of Si arranged in a honeycomb structure, has been predicted to give rise to massless Dirac fermions, akin to graphene. However, Si structures grown on a supporting substrate can show properties that strongly deviate from the freestanding case. Here, combining scanning tunneling microscopy/spectroscopy and differential conductance mapping, we show that the electrical properties of the (√3 x √3) phase of few-layer Si grown on Ag(111) strongly depend on film thickness, where the electron phase coherence length decreases and the free-electron-like surface state gradually diminishes when approaching the interface. These features are presumably attributable to the inelasticmore » inter-band electron-electron scattering originating from the overlap between the surface state, interface state and the bulk state of the substrate. We further demonstrate that the intrinsic electronic structure of the as grown (√3 x √3) phase is identical to that of the (√3 x √3) R30° reconstructed Ag on Si(111), both of which exhibit the parabolic energy-momentum dispersion relation with comparable electron effective masses. Lastly, these findings highlight the essential role of interfacial coupling on the properties of two-dimensional Si structures grown on supporting substrates, which should be thoroughly scrutinized in pursuit of silicene.« less

Head-body righting reflex from the supine position and preparatory eye movements.

PubMed

Troiani, Diana; Ferraresi, Aldo; Manni, Ermanno

2005-05-01

Saccular and utricular maculae can provide information on the supine static position, considering that both have pronounced curved structures with hair cells having a variety of polarization vectors that enable them to sense an inverted position and thus direct the righting reflex. The vestibular system is essential for the structuring of motor behaviour, senses linear and angular acceleration and has a strong influence on posture and balance at rest, during locomotion and in head body righting reflexes. Using guinea pigs in the supine position with a symmetrical head and trunk position, the ocular position was analysed to ascertain whether any ocular movement that occurred would adopt a spatial deviation indicative of the subsequent head and body righting. The characteristics of the righting reflex (direction, latency, duration and velocity) were analysed in guinea pigs from position signals obtained from search coils implanted in the eye, head and pelvis. The animals were kept in a supine position for a few seconds or even minutes with the eyes in a stable primary position and the head and body symmetrical and immobile. The righting reflex took place either immediately or after a slow deviation of the eyes. In both cases the righting sequence (eyes, head, body) was stereotyped and consistent. The direction of head and body righting was along the longitudinal axis of the animal and was either clockwise or anticlockwise and the direction of righting was related to the direction of the eye deviation. The ocular deviation and the direction of deviation that initiated and determined the direction of the righting reflex could be explained by possible otolithic activation.

Towards Monitoring Biodiversity in Amazonian Forests: How Regular Samples Capture Meso-Scale Altitudinal Variation in 25 km2 Plots

PubMed Central

Norris, Darren; Fortin, Marie-Josée; Magnusson, William E.

2014-01-01

Background Ecological monitoring and sampling optima are context and location specific. Novel applications (e.g. biodiversity monitoring for environmental service payments) call for renewed efforts to establish reliable and robust monitoring in biodiversity rich areas. As there is little information on the distribution of biodiversity across the Amazon basin, we used altitude as a proxy for biological variables to test whether meso-scale variation can be adequately represented by different sample sizes in a standardized, regular-coverage sampling arrangement. Methodology/Principal Findings We used Shuttle-Radar-Topography-Mission digital elevation values to evaluate if the regular sampling arrangement in standard RAPELD (rapid assessments (“RAP”) over the long-term (LTER [“PELD” in Portuguese])) grids captured patters in meso-scale spatial variation. The adequacy of different sample sizes (n = 4 to 120) were examined within 32,325 km2/3,232,500 ha (1293×25 km2 sample areas) distributed across the legal Brazilian Amazon. Kolmogorov-Smirnov-tests, correlation and root-mean-square-error were used to measure sample representativeness, similarity and accuracy respectively. Trends and thresholds of these responses in relation to sample size and standard-deviation were modeled using Generalized-Additive-Models and conditional-inference-trees respectively. We found that a regular arrangement of 30 samples captured the distribution of altitude values within these areas. Sample size was more important than sample standard deviation for representativeness and similarity. In contrast, accuracy was more strongly influenced by sample standard deviation. Additionally, analysis of spatially interpolated data showed that spatial patterns in altitude were also recovered within areas using a regular arrangement of 30 samples. Conclusions/Significance Our findings show that the logistically feasible sample used in the RAPELD system successfully recovers meso-scale altitudinal patterns. This suggests that the sample size and regular arrangement may also be generally appropriate for quantifying spatial patterns in biodiversity at similar scales across at least 90% (≈5 million km2) of the Brazilian Amazon. PMID:25170894

Borehole deviation and correction factor data for selected wells in the eastern Snake River Plain aquifer at and near the Idaho National Laboratory, Idaho

USGS Publications Warehouse

Twining, Brian V.

2016-11-29

The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Energy, has maintained a water-level monitoring program at the Idaho National Laboratory (INL) since 1949. The purpose of the program is to systematically measure and report water-level data to assess the eastern Snake River Plain aquifer and long term changes in groundwater recharge, discharge, movement, and storage. Water-level data are commonly used to generate potentiometric maps and used to infer increases and (or) decreases in the regional groundwater system. Well deviation is one component of water-level data that is often overlooked and is the result of the well construction and the well not being plumb. Depending on measured slant angle, where well deviation generally increases linearly with increasing slant angle, well deviation can suggest artificial anomalies in the water table. To remove the effects of well deviation, the USGS INL Project Office applies a correction factor to water-level data when a well deviation survey indicates a change in the reference elevation of greater than or equal to 0.2 ft.Borehole well deviation survey data were considered for 177 wells completed within the eastern Snake River Plain aquifer, but not all wells had deviation survey data available. As of 2016, USGS INL Project Office database includes: 57 wells with gyroscopic survey data; 100 wells with magnetic deviation survey data; 11 wells with erroneous gyroscopic data that were excluded; and, 68 wells with no deviation survey data available. Of the 57 wells with gyroscopic deviation surveys, correction factors for 16 wells ranged from 0.20 to 6.07 ft and inclination angles (SANG) ranged from 1.6 to 16.0 degrees. Of the 100 wells with magnetic deviation surveys, a correction factor for 21 wells ranged from 0.20 to 5.78 ft and SANG ranged from 1.0 to 13.8 degrees, not including the wells that did not meet the correction factor criteria of greater than or equal to 0.20 ft.Forty-seven wells had gyroscopic and magnetic deviation survey data for the same well. Datasets for both survey types were compared for the same well to determine whether magnetic survey data were consistent with gyroscopic survey data. Of those 47 wells, 96 percent showed similar correction factor estimates (≤ 0.20 ft) for both magnetic and gyroscopic well deviation surveys. A linear comparison of correction factor estimates for both magnetic and gyroscopic deviation well surveys for all 47 wells indicate good linear correlation, represented by an r-squared of 0.88. The correction factor difference between the gyroscopic and magnetic surveys for 45 of 47 wells ranged from 0.00 to 0.18 ft, not including USGS 57 and USGS 125. Wells USGS 57 and USGS 125 show a correction factor difference of 2.16 and 0.36 ft, respectively; however, review of the data files suggest erroneous SANG data for both magnetic deviation well surveys. The difference in magnetic and gyroscopic well deviation SANG measurements, for all wells, ranged from 0.0 to 0.9 degrees. These data indicate good agreement between SANG data measured using the magnetic deviation survey methods and SANG data measured using gyroscopic deviation survey methods, even for surveys collected years apart.

Dosimetry audit simulation of treatment planning system in multicenters radiotherapy

NASA Astrophysics Data System (ADS)

Kasmuri, S.; Pawiro, S. A.

2017-07-01

Treatment Planning System (TPS) is an important modality that determines radiotherapy outcome. TPS requires input data obtained through commissioning and the potentially error occurred. Error in this stage may result in the systematic error. The aim of this study to verify the TPS dosimetry to know deviation range between calculated and measurement dose. This study used CIRS phantom 002LFC representing the human thorax and simulated all external beam radiotherapy stages. The phantom was scanned using CT Scanner and planned 8 test cases that were similar to those in clinical practice situation were made, tested in four radiotherapy centers. Dose measurement using 0.6 cc ionization chamber. The results of this study showed that generally, deviation of all test cases in four centers was within agreement criteria with average deviation about -0.17±1.59 %, -1.64±1.92 %, 0.34±1.34 % and 0.13±1.81 %. The conclusion of this study was all TPS involved in this study showed good performance. The superposition algorithm showed rather poor performance than either analytic anisotropic algorithm (AAA) and convolution algorithm with average deviation about -1.64±1.92 %, -0.17±1.59 % and -0.27±1.51 % respectively.

Adaptive Neural Mechanism for Listing’s Law Revealed in Patients with Skew Deviation Caused by Brainstem or Cerebellar Lesion

PubMed Central

Fesharaki, Maryam; Karagiannis, Peter; Tweed, Douglas; Sharpe, James A.; Wong, Agnes M. F.

2016-01-01

Purpose Skew deviation is a vertical strabismus caused by damage to the otolithic–ocular reflex pathway and is associated with abnormal ocular torsion. This study was conducted to determine whether patients with skew deviation show the normal pattern of three-dimensional eye control called Listing’s law, which specifies the eye’s torsional angle as a function of its horizontal and vertical position. Methods Ten patients with skew deviation caused by brain stem or cerebellar lesions and nine normal control subjects were studied. Patients with diplopia and neurologic symptoms less than 1 month in duration were designated as acute (n = 4) and those with longer duration were classified as chronic (n = 10). Serial recordings were made in the four patients with acute skew deviation. With the head immobile, subjects made saccades to a target that moved between straight ahead and eight eccentric positions, while wearing search coils. At each target position, fixation was maintained for 3 seconds before the next saccade. From the eye position data, the plane of best fit, referred to as Listing’s plane, was fitted. Violations of Listing’s law were quantified by computing the “thickness” of this plane, defined as the SD of the distances to the plane from the data points. Results Both the hypertropic and hypotropic eyes in patients with acute skew deviation violated Listing’s and Donders’ laws—that is, the eyes did not show one consistent angle of torsion in any given gaze direction, but rather an abnormally wide range of torsional angles. In contrast, each eye in patients with chronic skew deviation obeyed the laws. However, in chronic skew deviation, Listing’s planes in both eyes had abnormal orientations. Conclusions Patients with acute skew deviation violated Listing’s law, whereas those with chronic skew deviation obeyed it, indicating that despite brain lesions, neural adaptation can restore Listing’s law so that the neural linkage between horizontal, vertical, and torsional eye position remains intact. Violation of Listing’s and Donders’ laws during fixation arises primarily from torsional drifts, indicating that patients with acute skew deviation have unstable torsional gaze holding that is independent of their horizontal–vertical eye positions. PMID:18172094

A massive pulsar in a compact relativistic binary.

PubMed

Antoniadis, John; Freire, Paulo C C; Wex, Norbert; Tauris, Thomas M; Lynch, Ryan S; van Kerkwijk, Marten H; Kramer, Michael; Bassa, Cees; Dhillon, Vik S; Driebe, Thomas; Hessels, Jason W T; Kaspi, Victoria M; Kondratiev, Vladislav I; Langer, Norbert; Marsh, Thomas R; McLaughlin, Maura A; Pennucci, Timothy T; Ransom, Scott M; Stairs, Ingrid H; van Leeuwen, Joeri; Verbiest, Joris P W; Whelan, David G

2013-04-26

Many physically motivated extensions to general relativity (GR) predict substantial deviations in the properties of spacetime surrounding massive neutron stars. We report the measurement of a 2.01 ± 0.04 solar mass (M⊙) pulsar in a 2.46-hour orbit with a 0.172 ± 0.003 M⊙ white dwarf. The high pulsar mass and the compact orbit make this system a sensitive laboratory of a previously untested strong-field gravity regime. Thus far, the observed orbital decay agrees with GR, supporting its validity even for the extreme conditions present in the system. The resulting constraints on deviations support the use of GR-based templates for ground-based gravitational wave detectors. Additionally, the system strengthens recent constraints on the properties of dense matter and provides insight to binary stellar astrophysics and pulsar recycling.

Parabolic trough receiver heat loss and optical efficiency round robin 2015/2016

NASA Astrophysics Data System (ADS)

Pernpeintner, Johannes; Schiricke, Björn; Sallaberry, Fabienne; de Jalón, Alberto García; López-Martín, Rafael; Valenzuela, Loreto; de Luca, Antonio; Georg, Andreas

2017-06-01

A round robin for parabolic trough receiver heat loss and optical efficiency in the laboratory was performed between five institutions using five receivers in 2015/2016. Heat loss testing was performed at three cartridge heater test benches and one Joule heating test bench in the temperature range between 100 °C and 550 °C. Optical efficiency testing was performed with two spectrometric test bench and one calorimetric test bench. Heat loss testing results showed standard deviations at the order of 6% to 12 % for most temperatures and receivers and a standard deviation of 17 % for one receiver at 100 °C. Optical efficiency is presented normalized for laboratories showing standard deviations of 0.3 % to 1.3 % depending on the receiver.

Hurricane track forecast cones from fluctuations

PubMed Central

Meuel, T.; Prado, G.; Seychelles, F.; Bessafi, M.; Kellay, H.

2012-01-01

Trajectories of tropical cyclones may show large deviations from predicted tracks leading to uncertainty as to their landfall location for example. Prediction schemes usually render this uncertainty by showing track forecast cones representing the most probable region for the location of a cyclone during a period of time. By using the statistical properties of these deviations, we propose a simple method to predict possible corridors for the future trajectory of a cyclone. Examples of this scheme are implemented for hurricane Ike and hurricane Jimena. The corridors include the future trajectory up to at least 50 h before landfall. The cones proposed here shed new light on known track forecast cones as they link them directly to the statistics of these deviations. PMID:22701776

Monoclinic distortion and magnetic coupling in the double perovskite Sr{sub 2−x}Ca{sub x}YRuO{sub 6}

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

Bernardo, P.L.; Ghivelder, L.; Eslava, G.G.

2014-12-15

Abstracts: This work investigates in the insulating double perovskites Sr{sub 2−x}Ca{sub x}YRuO{sub 6}. We address the angular dependence of the strength of the magnetic coupling due to the deviation from planarity of the basal layers of the monoclinic structure, characterized by the in-plane angle α<180°, in order to probe the impact of the structural distortions in the magnetic properties of the compounds. High resolution x-ray powder diffraction, susceptibility, and specific heat measurements were performed. The deviation from planarity significantly increases (α=144° for x=1) while the bond distances vary in a complex way as a consequence of the strong monoclinic distortion.more » We found that the magnetic transition temperature, T{sub M}, shows a linear dependence on cos [(π−α)/2]. This result is discussed in terms of t{sub 2g}(π)–e{sub g}(σ) mixing of the magnetic orbitals of the Ru{sup 5+} ions and unbalanced competitive super-exchange interactions. The deleterious effect of Ca doping for the magnetic coupling is confirmed by the reduction in the short-range antiferromagnetic correlations characteristic of the parent compound at T>>T{sub M} and the enhancement of magnetic frustration for T« less

Model and parametric uncertainty in source-based kinematic models of earthquake ground motion

USGS Publications Warehouse

Hartzell, Stephen; Frankel, Arthur; Liu, Pengcheng; Zeng, Yuehua; Rahman, Shariftur

2011-01-01

Four independent ground-motion simulation codes are used to model the strong ground motion for three earthquakes: 1994 Mw 6.7 Northridge, 1989 Mw 6.9 Loma Prieta, and 1999 Mw 7.5 Izmit. These 12 sets of synthetics are used to make estimates of the variability in ground-motion predictions. In addition, ground-motion predictions over a grid of sites are used to estimate parametric uncertainty for changes in rupture velocity. We find that the combined model uncertainty and random variability of the simulations is in the same range as the variability of regional empirical ground-motion data sets. The majority of the standard deviations lie between 0.5 and 0.7 natural-log units for response spectra and 0.5 and 0.8 for Fourier spectra. The estimate of model epistemic uncertainty, based on the different model predictions, lies between 0.2 and 0.4, which is about one-half of the estimates for the standard deviation of the combined model uncertainty and random variability. Parametric uncertainty, based on variation of just the average rupture velocity, is shown to be consistent in amplitude with previous estimates, showing percentage changes in ground motion from 50% to 300% when rupture velocity changes from 2.5 to 2.9 km/s. In addition, there is some evidence that mean biases can be reduced by averaging ground-motion estimates from different methods.

Bright nanoscale source of deterministic entangled photon pairs violating Bell's inequality.

PubMed

Jöns, Klaus D; Schweickert, Lucas; Versteegh, Marijn A M; Dalacu, Dan; Poole, Philip J; Gulinatti, Angelo; Giudice, Andrea; Zwiller, Val; Reimer, Michael E

2017-05-10

Global, secure quantum channels will require efficient distribution of entangled photons. Long distance, low-loss interconnects can only be realized using photons as quantum information carriers. However, a quantum light source combining both high qubit fidelity and on-demand bright emission has proven elusive. Here, we show a bright photonic nanostructure generating polarization-entangled photon pairs that strongly violates Bell's inequality. A highly symmetric InAsP quantum dot generating entangled photons is encapsulated in a tapered nanowire waveguide to ensure directional emission and efficient light extraction. We collect ~200 kHz entangled photon pairs at the first lens under 80 MHz pulsed excitation, which is a 20 times enhancement as compared to a bare quantum dot without a photonic nanostructure. The performed Bell test using the Clauser-Horne-Shimony-Holt inequality reveals a clear violation (S CHSH  > 2) by up to 9.3 standard deviations. By using a novel quasi-resonant excitation scheme at the wurtzite InP nanowire resonance to reduce multi-photon emission, the entanglement fidelity (F = 0.817 ± 0.002) is further enhanced without temporal post-selection, allowing for the violation of Bell's inequality in the rectilinear-circular basis by 25 standard deviations. Our results on nanowire-based quantum light sources highlight their potential application in secure data communication utilizing measurement-device-independent quantum key distribution and quantum repeater protocols.

Transverse dental compensation in relation to sagittal and transverse skeletal discrepancies in skeletal Class III patients.

PubMed

Ahn, Jaechan; Kim, Sung-Jin; Lee, Ji-Yeon; Chung, Chooryung J; Kim, Kyung-Ho

2017-01-01

The purposes of this study were to compare the buccolingual inclinations of the posterior teeth in skeletal Class III patients with and without facial asymmetry with those of skeletal Class I patients and to investigate their relationships with sagittal and transverse skeletal discrepancies. Sixty-three skeletal Class III adult patients were divided into 2 groups according to the degree of menton deviation: a symmetry group with deviation less than 2 mm (n = 30), and an asymmetry group with deviation greater than 4 mm (n = 33). The control group comprised 25 skeletal Class I patients. The buccolingual inclinations of the posterior teeth measured on cone-beam computed tomography images were compared among the 3 groups, and regression analysis was performed to investigate the relationships between the inclinations and the sagittal and transverse skeletal discrepancies. The symmetry group showed greater buccal inclinations of the maxillary posterior teeth and lingual inclinations of the mandibular second molars than did the control, and this was correlated with the ANB angles. The deviated sides in the asymmetry group showed the greatest transverse dental compensation, which was correlated with menton deviation, whereas the nondeviated sides showed no significant transverse dental compensation. Transverse dental compensation is closely related to sagittal and transverse skeletal discrepancy in skeletal Class III patients. Copyright © 2017 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Sub-grain induced crack deviation in multi-crystalline silicon

NASA Astrophysics Data System (ADS)

Zhao, Lv; Nelias, Daniel; Bardel, Didier; Wang, Meng; Marie, Benoit

2017-06-01

The fracture process in crystalline silicon is dictated by energy dissipation. Here, we show that sub-grains can deviate the crack path from the most energetically favorable ( 111) plane. Albeit a small misorientation across the sub-grain boundary is identified, upon entering into the sub-grain region, the crack either slightly deviates from the ideal ( 111) plane or directly chooses the secondly most favorable ( 110) one. We propose that the deviation is related to the dislocation core in the ( 111) crystal plane, which leads to a discontinuous atom debonding process and consequently a pronounced lattice trapping. In this circumstance, localized crystal defects prevail in the fracture process of silicon, while energetical criterion fails to interpret the crack path.

Drude weight and optical conductivity of a two-dimensional heavy-hole gas with k-cubic spin-orbit interactions

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

Mawrie, Alestin; Ghosh, Tarun Kanti

We present a detailed theoretical study on zero-frequency Drude weight and optical conductivity of a two-dimensional heavy-hole gas (2DHG) with k-cubic Rashba and Dresselhaus spin-orbit interactions. The presence of k-cubic spin-orbit couplings strongly modifies the Drude weight in comparison to the electron gas with k-linear spin-orbit couplings. For large hole density and strong k-cubic spin-orbit couplings, the density dependence of Drude weight deviates from the linear behavior. We establish a relation between optical conductivity and the Berry connection. Unlike two-dimensional electron gas with k-linear spin-orbit couplings, we explicitly show that the optical conductivity does not vanish even for equal strengthmore » of the two spin-orbit couplings. We attribute this fact to the non-zero Berry phase for equal strength of k-cubic spin-orbit couplings. The least photon energy needed to set in the optical transition in hole gas is one order of magnitude smaller than that of electron gas. Types of two van Hove singularities appear in the optical spectrum are also discussed.« less

Reconciling intuitive physics and Newtonian mechanics for colliding objects.

PubMed

Sanborn, Adam N; Mansinghka, Vikash K; Griffiths, Thomas L

2013-04-01

People have strong intuitions about the influence objects exert upon one another when they collide. Because people's judgments appear to deviate from Newtonian mechanics, psychologists have suggested that people depend on a variety of task-specific heuristics. This leaves open the question of how these heuristics could be chosen, and how to integrate them into a unified model that can explain human judgments across a wide range of physical reasoning tasks. We propose an alternative framework, in which people's judgments are based on optimal statistical inference over a Newtonian physical model that incorporates sensory noise and intrinsic uncertainty about the physical properties of the objects being viewed. This noisy Newton framework can be applied to a multitude of judgments, with people's answers determined by the uncertainty they have for physical variables and the constraints of Newtonian mechanics. We investigate a range of effects in mass judgments that have been taken as strong evidence for heuristic use and show that they are well explained by the interplay between Newtonian constraints and sensory uncertainty. We also consider an extended model that handles causality judgments, and obtain good quantitative agreement with human judgments across tasks that involve different judgment types with a single consistent set of parameters.

Open quantum maps from complex scaling of kicked scattering systems

NASA Astrophysics Data System (ADS)

Mertig, Normann; Shudo, Akira

2018-04-01

We derive open quantum maps from periodically kicked scattering systems and discuss the computation of their resonance spectra in terms of theoretically grounded methods, such as complex scaling and sufficiently weak absorbing potentials. In contrast, we also show that current implementations of open quantum maps, based on strong absorptive or even projective openings, fail to produce the resonance spectra of kicked scattering systems. This comparison pinpoints flaws in current implementations of open quantum maps, namely, the inability to separate resonance eigenvalues from the continuum as well as the presence of diffraction effects due to strong absorption. The reported deviations from the true resonance spectra appear, even if the openings do not affect the classical trapped set, and become appreciable for shorter-lived resonances, e.g., those associated with chaotic orbits. This makes the open quantum maps, which we derive in this paper, a valuable alternative for future explorations of quantum-chaotic scattering systems, for example, in the context of the fractal Weyl law. The results are illustrated for a quantum map model whose classical dynamics exhibits key features of ionization and a trapped set which is organized by a topological horseshoe.

Dependence of Ion Dynamics on the Polymer Chain Length in Poly(ethylene oxide)-Based Polymer Electrolytes.

PubMed

Chattoraj, Joyjit; Knappe, Marisa; Heuer, Andreas

2015-06-04

It is known from experiments that in the polymer electrolyte system, which contains poly(ethylene oxide) chains (PEO), lithium-cations (Li(+)), and bis(trifluoromethanesulfonyl)imide-anions (TFSI(-)), the cation and the anion diffusion and the ionic conductivity exhibit a similar chain-length dependence: with increasing chain length, they start dropping steadily, and later, they saturate to constant values. These results are surprising because Li-cations are strongly correlated with the polymer chains, whereas TFSI-anions do not have such bonding. To understand this phenomenon, we perform molecular dynamics simulations of this system for four different polymer chain lengths. The diffusion results obtained from our simulations display excellent agreement with the experimental data. The cation transport model based on the Rouse dynamics can successfully quantify the Li-diffusion results, which correlates Li diffusion with the polymer center-of-mass motion and the polymer segmental motion. The ionic conductivity as a function of the chain length is then estimated based on the chain-length-dependent ion diffusion, which shows a temperature-dependent deviation for short chain lengths. We argue that in the first regime, counterion correlations modify the conductivity, whereas for the long chains, the system behaves as a strong electrolyte.

Intermittency in 2D soap film turbulence

NASA Astrophysics Data System (ADS)

Cerbus, R. T.; Goldburg, W. I.

2013-10-01

The Reynolds number dependency of intermittency for 2D turbulence is studied in a flowing soap film. The Reynolds number used here is the Taylor microscale Reynolds number Rλ, which ranges from 20 to 800. Strong intermittency is found for both the inverse energy and direct enstrophy cascades as measured by (a) the pdf of velocity differences P(δu(r)) at inertial scales r, (b) the kurtosis of P(∂xu), and (c) the scaling of the so-called intermittency exponent μ, which is zero if intermittency is absent. Measures (b) and (c) are quantitative, while (a) is qualitative. These measurements are in disagreement with some previous results but not all. The velocity derivatives are nongaussian at all Rλ but show signs of becoming gaussian as Rλ increases beyond the largest values that could be reached. The kurtosis of P(δu(r)) at various r indicates that the intermittency is scale dependent. The structure function scaling exponents also deviate strongly from the Kraichnan prediction. For the enstrophy cascade, the intermittency decreases as a power law in Rλ. This study suggests the need for a new look at the statistics of 2D turbulence.

Collective behavior of stock price movements in an emerging market

NASA Astrophysics Data System (ADS)

Pan, Raj Kumar; Sinha, Sitabhra

2007-10-01

To investigate the universality of the structure of interactions in different markets, we analyze the cross-correlation matrix C of stock price fluctuations in the National Stock Exchange (NSE) of India. We find that this emerging market exhibits strong correlations in the movement of stock prices compared to developed markets, such as the New York Stock Exchange (NYSE). This is shown to be due to the dominant influence of a common market mode on the stock prices. By comparison, interactions between related stocks, e.g., those belonging to the same business sector, are much weaker. This lack of distinct sector identity in emerging markets is explicitly shown by reconstructing the network of mutually interacting stocks. Spectral analysis of C for NSE reveals that, the few largest eigenvalues deviate from the bulk of the spectrum predicted by random matrix theory, but they are far fewer in number compared to, e.g., NYSE. We show this to be due to the relative weakness of intrasector interactions between stocks, compared to the market mode, by modeling stock price dynamics with a two-factor model. Our results suggest that the emergence of an internal structure comprising multiple groups of strongly coupled components is a signature of market development.

Plasma flow around and charge distribution of a dust cluster in a rf discharge

NASA Astrophysics Data System (ADS)

Schleede, J.; Lewerentz, L.; Bronold, F. X.; Schneider, R.; Fehske, H.

2018-04-01

We employ a particle-in-cell Monte Carlo collision/particle-particle particle-mesh simulation to study the plasma flow around and the charge distribution of a three-dimensional dust cluster in the sheath of a low-pressure rf argon discharge. The geometry of the cluster and its position in the sheath are fixed to the experimental values, prohibiting a mechanical response of the cluster. Electrically, however, the cluster and the plasma environment, mimicking also the experimental situation, are coupled self-consistently. We find a broad distribution of the charges collected by the grains. The ion flux shows on the scale of the Debye length strong focusing and shadowing inside and outside the cluster due to the attraction of the ions to the negatively charged grains, whereas the electron flux is characterized on this scale only by a weak spatial modulation of its magnitude depending on the rf phase. On the scale of the individual dust potentials, however, the electron flux deviates in the vicinity of the cluster strongly from the laminar flow associated with the plasma sheath. It develops convection patterns to compensate for the depletion of electrons inside the dust cluster.

Using walker during walking: a pilot study for health elder.

PubMed

Po-Chan, Yeh; Cherng-Yee, Leung

2012-01-01

Walker operation completely relies on the walker handle, however most marketed walkers possess two horizontal handles. Several researchers have suggested that horizontal handles might lead to wrist injury. Therefore, the purpose of this study is to assess the relevant design aspects of walker for elderly people. 28 elders participated in this study; when the experiment was started, subject walked on the tile for 3 meter distance twice by using walker. Data for analysis were selected at the corresponding wrist deviation and vertical force. The results showed that during walker using, the mean wrist deviation was greater than zero. The largest vertical force is significantly larger than the smallest one, and different wrist deviation occurred at three phases, the largest wrist deviation while raising walker is larger than the smallest one, however, no significant different was found between the largest and smallest wrist deviation while pressing walker. No significant correlation occurred between weight and wrist deviation. The correlation between weight and vertical force was significantly positive. With wrist deviation walker use may cause injury to upper-limb, however wrists remain in a neutral position during hand movement to prevent damage. The findings of this study should improve the design of walker handles to reduce the wrist deviations of users.

Behavioral Economics Applied to Energy Demand Analysis: A Foundation

EIA Publications

2014-01-01

Neoclassical economics has shaped our understanding of human behavior for several decades. While still an important starting point for economic studies, neoclassical frameworks have generally imposed strong assumptions, for example regarding utility maximization, information, and foresight, while treating consumer preferences as given or external to the framework. In real life, however, such strong assumptions tend to be less than fully valid. Behavioral economics refers to the study and formalizing of theories regarding deviations from traditionally-modeled economic decision-making in the behavior of individuals. The U.S. Energy Information Administration (EIA) has an interest in behavioral economics as one influence on energy demand.

Electrical and Thermal Transport in Inhomogeneous Luttinger Liquids

DOE PAGES

DeGottardi, Wade; Matveev, K. A.

2015-06-12

In this paper, we study the transport properties of long quantum wires by generalizing the Luttinger liquid approach to allow for the finite lifetime of the bosonic excitations. Our theory accounts for long-range disorder and strong electron interactions, both of which are common features of experiments with quantum wires. We obtain the electrical and thermal resistances and thermoelectric properties of such quantum wires and find a strong deviation from perfect conductance quantization. Finally, we cast our results in terms of the thermal conductivity and bulk viscosity of the electron liquid and give the temperature scale above which the transport canmore » be described by classical hydrodynamics.« less

ω→π0γ* and ϕ→π0γ* transition form factors in dispersion theory

NASA Astrophysics Data System (ADS)

Schneider, Sebastian P.; Kubis, Bastian; Niecknig, Franz

2012-09-01

We calculate the ω→π0γ* and ϕ→π0γ* electromagnetic transition form factors based on dispersion theory, relying solely on a previous dispersive analysis of the corresponding three-pion decays and the pion vector form factor. We compare our findings to recent measurements of the ω→π0μ+μ- decay spectrum by the NA60 collaboration, and strongly encourage experimental investigation of the Okubo-Zweig-Iizuka forbidden ϕ→π0ℓ+ℓ- decays in order to understand the strong deviations from vector-meson dominance found in these transition form factors.

Who pays for public employee health costs?

PubMed

Clemens, Jeffrey; Cutler, David M

2014-12-01

We analyze the incidence of public-employee health benefits. Because these benefits are negotiated through the political process, relevant labor market institutions deviate significantly from the competitive, private-sector benchmark. Empirically, we find that roughly 15 percent of the cost of recent benefit growth was passed onto school district employees through reductions in wages and salaries. Strong teachers' unions were associated with relatively strong linkages between benefit growth and growth in total compensation. Our analysis is consistent with the view that the costs of public workers' benefits are difficult to monitor, contributing to benefit oriented, and often under-funded, compensation schemes. Copyright © 2014 Elsevier B.V. All rights reserved.

Heightened odds of large earthquakes near Istanbul: an interaction-based probability calculation

USGS Publications Warehouse

Parsons, T.; Toda, S.; Stein, R.S.; Barka, A.; Dieterich, J.H.

2000-01-01

We calculate the probability of strong shaking in Istanbul, an urban center of 10 million people, from the description of earthquakes on the North Anatolian fault system in the Marmara Sea during the past 500 years and test the resulting catalog against the frequency of damage in Istanbul during the preceding millennium, departing from current practice, we include the time-dependent effect of stress transferred by the 1999 moment magnitude M = 7.4 Izmit earthquake to faults nearer to Istanbul. We find a 62 ± 15% probability (one standard deviation) of strong shaking during the next 30 years and 32 ± 12% during the next decade.

Local suppression of the superfluid density of PuCoGa5 by strong onsite disorder

NASA Astrophysics Data System (ADS)

Das, Tanmoy; Zhu, Jian-Xin; Graf, Matthias J.

2011-10-01

We present superfluid density calculations for the unconventional superconductor PuCoGa5 by solving the real-space Bogoliubov-de Gennes equations on a square lattice within the Swiss-cheese model in the presence of strong onsite disorder. We find that, despite strong electronic inhomogeneity, one can establish a one-to-one correspondence between the local maps of the density of states, superconducting order parameter, and superfluid density. In this model, strong onsite impurity scattering punches localized holes into the fabric of d-wave superconductivity similar to a Swiss cheese. Already, a two-dimensional impurity concentration of nimp=4% gives rise to a pronounced short-range suppression of the order parameter and a suppression of the superconducting transition temperature Tc by roughly 20% compared to its pure limit value Tc0, whereas the superfluid density ρs is reduced drastically by about 70%. This result is consistent with available experimental data for aged (400-day-old) and fresh (25-day-old) PuCoGa5 superconducting samples. In addition, we show that the T2 dependence of the low-T superfluid density, a signature of dirty d-wave superconductivity, originates from a combined effect in the density of states of “gap filling” and “gap closing.” Finally, we demonstrate that the Uemuera plot of Tc versus ρs deviates sharply from the conventional Abrikosov-Gor’kov theory for radiation-induced defects in PuCoGa5, but follows the same trend of short-coherence-length high-Tc cuprate superconductors.

Density-dependent sex ratio and sex-specific preference for host traits in parasitic bat flies.

PubMed

Szentiványi, Tamara; Vincze, Orsolya; Estók, Péter

2017-08-29

Deviation of sex ratios from unity in wild animal populations has recently been demonstrated to be far more prevalent than previously thought. Ectoparasites are prominent examples of this bias, given that their sex ratios vary from strongly female- to strongly male-biased both among hosts and at the metapopulation level. To date our knowledge is very limited on how and why these biased sex ratios develop. It was suggested that sex ratio and sex-specific aggregation of ectoparasites might be shaped by the ecology, behaviour and physiology of both hosts and their parasites. Here we investigate a highly specialised, hematophagous bat fly species with strong potential to move between hosts, arguably limited inbreeding effects, off-host developmental stages and extended parental care. We collected a total of 796 Nycteribia kolenatii bat flies from 147 individual bats using fumigation and subsequently determined their sex. We report a balanced sex ratio at the metapopulation level and a highly variable sex ratio among infrapopulations ranging from 100% male to 100% female. We show that infrapopulation sex ratio is not random and is highly correlated with infrapopulation size. Sex ratio is highly male biased in small and highly female biased in large infrapopulations. We show that this pattern is most probably the result of sex-specific preference in bat flies for host traits, most likely combined with a higher mobility of males. We demonstrate that female bat flies exert a strong preference for high host body condition and female hosts, while the distribution of males is more even. Our results suggest that locally biased sex ratios can develop due to sex-specific habitat preference of parasites. Moreover, it is apparent that the sex of both hosts and parasites need to be accounted for when a better understanding of host-parasite systems is targeted.

Validating the energy transport modeling of the DIII-D and EAST ramp up experiments using TSC

NASA Astrophysics Data System (ADS)

Liu, Li; Guo, Yong; Chan, Vincent; Mao, Shifeng; Wang, Yifeng; Pan, Chengkang; Luo, Zhengping; Zhao, Hailin; Ye, Minyou

2017-06-01

The confidence in ramp up scenario design of the China fusion engineering test reactor (CFETR) can be significantly enhanced using validated transport models to predict the current profile and temperature profile. In the tokamak simulation code (TSC), two semi-empirical energy transport models (the Coppi-Tang (CT) and BGB model) and three theory-based models (the GLF23, MMM95 and CDBM model) are investigated on the CFETR relevant ramp up discharges, including three DIII-D ITER-like ramp up discharges and one EAST ohmic discharge. For the DIII-D discharges, all the transport models yield dynamic {{\\ell}\\text{i}} within +/- 0.15 deviations except for some time points where the experimental fluctuation is very strong. All the models agree with the experimental {β\\text{p}} except that the CT model strongly overestimates {β\\text{p}} in the first half of ramp up phase. When applying the CT, CDBM and GLF23 model to estimate the internal flux, they show maximum deviations of more than 10% because of inaccuracies in the temperature profile predictions, while the BGB model performs best on the internal flux. Although all the models fall short in reproducing the dynamic {{\\ell}\\text{i}} evolution for the EAST tokamak, the result of the BGB model is the closest to the experimental {{\\ell}\\text{i}} . Based on these comparisons, we conclude that the BGB model is the most consistent among these models for simulating CFETR ohmic ramp-up. The CT model with improvement for better simulation of the temperature profiles in the first half of ramp up phase will also be attractive. For the MMM95, GLF23 and CDBM model, better prediction of the edge temperature will improve the confidence for CFETR L-mode simulation. Conclusive validation of any transport model will require extensive future investigation covering a larger variety discharges.

Flexner 3.0-Democratization of Medical Knowledge for the 21st Century: Teaching Medical Science Using K-12 General Pathology as a Gateway Course.

PubMed

Weinstein, Ronald S; Krupinski, Elizabeth A; Weinstein, John B; Graham, Anna R; Barker, Gail P; Erps, Kristine A; Holtrust, Angelette L; Holcomb, Michael J

2016-01-01

A medical school general pathology course has been reformatted into a K-12 general pathology course. This new course has been implemented at a series of 7 to 12 grade levels and the student outcomes compared. Typically, topics covered mirrored those in a medical school general pathology course serving as an introduction to the mechanisms of diseases. Assessment of student performance was based on their score on a multiple-choice final examination modeled after an examination given to medical students. Two Tucson area schools, in a charter school network, participated in the study. Statistical analysis of examination performances showed that there were no significant differences as a function of school ( F = 0.258, P = .6128), with students at school A having an average test scores of 87.03 (standard deviation = 8.99) and school B 86.00 (standard deviation = 8.18; F = 0.258, P = .6128). Analysis of variance was also conducted on the test scores as a function of gender and class grade. There were no significant differences as a function of gender ( F = 0.608, P = .4382), with females having an average score of 87.18 (standard deviation = 7.24) and males 85.61 (standard deviation = 9.85). There were also no significant differences as a function of grade level ( F = 0.627, P = .6003), with 7th graders having an average of 85.10 (standard deviation = 8.90), 8th graders 86.00 (standard deviation = 9.95), 9th graders 89.67 (standard deviation = 5.52), and 12th graders 86.90 (standard deviation = 7.52). The results demonstrated that middle and upper school students performed equally well in K-12 general pathology. Student course evaluations showed that the course met the student's expectations. One class voted K-12 general pathology their "elective course-of-the-year."

Flexner 3.0—Democratization of Medical Knowledge for the 21st Century

PubMed Central

Krupinski, Elizabeth A.; Weinstein, John B.; Graham, Anna R.; Barker, Gail P.; Erps, Kristine A.; Holtrust, Angelette L.; Holcomb, Michael J.

2016-01-01

A medical school general pathology course has been reformatted into a K-12 general pathology course. This new course has been implemented at a series of 7 to 12 grade levels and the student outcomes compared. Typically, topics covered mirrored those in a medical school general pathology course serving as an introduction to the mechanisms of diseases. Assessment of student performance was based on their score on a multiple-choice final examination modeled after an examination given to medical students. Two Tucson area schools, in a charter school network, participated in the study. Statistical analysis of examination performances showed that there were no significant differences as a function of school (F = 0.258, P = .6128), with students at school A having an average test scores of 87.03 (standard deviation = 8.99) and school B 86.00 (standard deviation = 8.18; F = 0.258, P = .6128). Analysis of variance was also conducted on the test scores as a function of gender and class grade. There were no significant differences as a function of gender (F = 0.608, P = .4382), with females having an average score of 87.18 (standard deviation = 7.24) and males 85.61 (standard deviation = 9.85). There were also no significant differences as a function of grade level (F = 0.627, P = .6003), with 7th graders having an average of 85.10 (standard deviation = 8.90), 8th graders 86.00 (standard deviation = 9.95), 9th graders 89.67 (standard deviation = 5.52), and 12th graders 86.90 (standard deviation = 7.52). The results demonstrated that middle and upper school students performed equally well in K-12 general pathology. Student course evaluations showed that the course met the student’s expectations. One class voted K-12 general pathology their “elective course-of-the-year.” PMID:28725762

Misperceptions in the Trajectories of Objects undergoing Curvilinear Motion

PubMed Central

Yilmaz, Ozgur; Tripathy, Srimant P.; Ogmen, Haluk

2012-01-01

Trajectory perception is crucial in scene understanding and action. A variety of trajectory misperceptions have been reported in the literature. In this study, we quantify earlier observations that reported distortions in the perceived shape of bilinear trajectories and in the perceived positions of their deviation. Our results show that bilinear trajectories with deviation angles smaller than 90 deg are perceived smoothed while those with deviation angles larger than 90 degrees are perceived sharpened. The sharpening effect is weaker in magnitude than the smoothing effect. We also found a correlation between the distortion of perceived trajectories and the perceived shift of their deviation point. Finally, using a dual-task paradigm, we found that reducing attentional resources allocated to the moving target causes an increase in the perceived shift of the deviation point of the trajectory. We interpret these results in the context of interactions between motion and position systems. PMID:22615775

A deviation display method for visualising data in mobile gamma-ray spectrometry.

PubMed

Kock, Peder; Finck, Robert R; Nilsson, Jonas M C; Ostlund, Karl; Samuelsson, Christer

2010-09-01

A real time visualisation method, to be used in mobile gamma-spectrometric search operations using standard detector systems is presented. The new method, called deviation display, uses a modified waterfall display to present relative changes in spectral data over energy and time. Using unshielded (137)Cs and (241)Am point sources and different natural background environments, the behaviour of the deviation displays is demonstrated and analysed for two standard detector types (NaI(Tl) and HPGe). The deviation display enhances positive significant changes while suppressing the natural background fluctuations. After an initialization time of about 10min this technique leads to a homogeneous display dominated by the background colour, where even small changes in spectral data are easy to discover. As this paper shows, the deviation display method works well for all tested gamma energies and natural background radiation levels and with both tested detector systems.

How do we assign punishment? The impact of minimal and maximal standards on the evaluation of deviants.

PubMed

Kessler, Thomas; Neumann, Jörg; Mummendey, Amélie; Berthold, Anne; Schubert, Thomas; Waldzus, Sven

2010-09-01

To explain the determinants of negative behavior toward deviants (e.g., punishment), this article examines how people evaluate others on the basis of two types of standards: minimal and maximal. Minimal standards focus on an absolute cutoff point for appropriate behavior; accordingly, the evaluation of others varies dichotomously between acceptable or unacceptable. Maximal standards focus on the degree of deviation from that standard; accordingly, the evaluation of others varies gradually from positive to less positive. This framework leads to the prediction that violation of minimal standards should elicit punishment regardless of the degree of deviation, whereas punishment in response to violations of maximal standards should depend on the degree of deviation. Four studies assessed or manipulated the type of standard and degree of deviation displayed by a target. Results consistently showed the expected interaction between type of standard (minimal and maximal) and degree of deviation on punishment behavior.

Endometrioid adenocarcinoma of the uterus with a minimal deviation invasive pattern.

PubMed

Landry, D; Mai, K T; Senterman, M K; Perkins, D G; Yazdi, H M; Veinot, J P; Thomas, J

2003-01-01

Minimal deviation adenocarcinoma of endometrioid type is a rare pathological entity. We describe a variant of typical endometrioid adenocarcinoma associated with minimal deviation adenocarcinoma of endometrioid type. One 'pilot' case of minimal deviation adenocarcinoma of endometrioid type associated with typical endometrioid adenocarcinoma was encountered at our institution in 2001. A second case of same type was received in consultation. We reviewed 168 consecutive hysterectomy specimens diagnosed with 'endometrioid adenocarcinoma' specifically to identify areas of minimal deviation adenocarcinoma of endometrioid type. Immunohistochemistry was done with the following antibodies: MIB1, p53, oestrogen receptor (ER), progesterone receptor (PR), cytokeratin 7 (CK7), cytokeratin 20 (CK20), carcinoembryonic antigen (CEA), and vimentin (VIM). Four additional cases of minimal deviation adenocarcinoma of endometrioid type were identified. All six cases of minimal deviation adenocarcinoma of endometrioid type were associated with superficial endometrioid adenocarcinoma. In two cases with a large amount of minimal deviation adenocarcinoma of endometrioid type, the cervix was involved. The immunoprofile of two representative cases was ER+, PR+, CK7+, CK20-, CEA-, VIM+. MIB1 immunostaining of four cases revealed little proliferative activity of the minimal deviation adenocarcinoma of endometrioid type glandular cells (0-1%) compared with the associated 'typical' endometrioid adenocarcinoma (20-30%). The same four cases showed no p53 immunostaining in minimal deviation adenocarcinoma of endometrioid type compared with a range of positive staining in the associated endometrioid adenocarcinoma. Minimal deviation adenocarcinoma of endometrioid type more often develops as a result of differentiation from typical endometrioid adenocarcinoma than de novo. Due to its deceptively benign microscopic appearance, minimal deviation adenocarcinoma of endometrioid type may be overlooked and may lead to incorrect assessment of tumour depth and pathological stage. There was a tendency for tumour with a large amount of minimal deviation adenocarcinoma of endometrioid type to invade the cervix.

A Correlational Study of Scoliosis and Trunk Balance in Adult Patients with Mandibular Deviation

PubMed Central

Yang, Yang; Wang, Na; Wang, Wenyong; Ding, Yin; Sun, Shiyao

2013-01-01

Previous studies have confirmed that patients with mandibular deviation often have abnormal morphology of their cervical vertebrae. However, the relationship between mandibular deviation, scoliosis, and trunk balance has not been studied. Currently, mandibular deviation is usually treated as a single pathology, which leads to poor clinical efficiency. We investigated the relationship of spine coronal morphology and trunk balance in adult patients with mandibular deviation, and compared the finding to those in healthy volunteers. 35 adult patients with skeletal mandibular deviation and 10 healthy volunteers underwent anterior X-ray films of the head and posteroanterior X-ray films of the spine. Landmarks and lines were drawn and measured on these films. The axis distance method was used to measure the degree of scoliosis and the balance angle method was used to measure trunk balance. The relationship of mandibular deviation, spine coronal morphology and trunk balance was evaluated with the Pearson correlation method. The spine coronal morphology of patients with mandibular deviation demonstrated an “S” type curve, while a straight line parallel with the gravity line was found in the control group (significant difference, p<0.01). The trunk balance of patients with mandibular deviation was disturbed (imbalance angle >1°), while the control group had a normal trunk balance (imbalance angle <1°). There was a significant difference between the two groups (p<0.01). The degree of scoliosis and shoulder imbalance correlated with the degree of mandibular deviation, and presented a linear trend. The direction of mandibular deviation was the same as that of the lateral bending of thoracolumbar vertebrae, which was opposite to the direction of lateral bending of cervical vertebrae. Our study shows the degree of mandibular deviation has a high correlation with the degree of scoliosis and trunk imbalance, all the three deformities should be clinically evaluated in the management of mandibular deviation. PMID:23555836

Perceptions of midline deviations among different facial types.

PubMed

Williams, Ryan P; Rinchuse, Daniel J; Zullo, Thomas G

2014-02-01

The correction of a deviated midline can involve complicated mechanics and a protracted treatment. The threshold below which midline deviations are considered acceptable might depend on multiple factors. The objective of this study was to evaluate the effect of facial type on laypersons' perceptions of various degrees of midline deviation. Smiling photographs of male and female subjects were altered to create 3 facial type variations (euryprosopic, mesoprosopic, and leptoprosopic) and deviations in the midline ranging from 0.0 to 4.0 mm. Evaluators rated the overall attractiveness and acceptability of each photograph. Data were collected from 160 raters. The overall threshold for the acceptability of a midline deviation was 2.92 ± 1.10 mm, with the threshold for the male subject significantly lower than that for the female subject. The euryprosopic facial type showed no decrease in mean attractiveness until the deviations were 2 mm or more. All other facial types were rated as decreasingly attractive from 1 mm onward. Among all facial types, the attractiveness of the male subject was only affected at deviations of 2 mm or greater; for the female subject, the attractiveness scores were significantly decreased at 1 mm. The mesoprosopic facial type was most attractive for the male subject but was the least attractive for the female subject. Facial type and sex may affect the thresholds at which a midline deviation is detected and above which a midline deviation is considered unacceptable. Both the euryprosopic facial type and male sex were associated with higher levels of attractiveness at relatively small levels of deviations. Copyright © 2014 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Demographic stochasticity in small remnant populations of the declining distylous plant Primula veris

USGS Publications Warehouse

Kery, M.; Matthies, D.; Schmid, B.

2003-01-01

We studied ecological consequences of distyly for the declining perennial plant Primula veris in the Swiss Jura. Distyly favours cross-fertilization and avoids inbreeding, but may lead to pollen limitation and reduced reproduction if morph frequencies deviate from 50 %. Disassortative mating is promoted by the reciprocal position of stigmas and anthers in the two morphs (pin and thrum) and by intramorph incompatibility and should result in equal frequencies of morphs at equilibrium. However, deviations could arise because of demographic stochasticity, the lower intra-morph incompatibility of the pin morph, and niche differentiation between morphs. Demographic stochasticity should result in symmetric deviations from an even morph frequency among populations and in increased deviations with decreasing population size. If crosses between pins occurred, these would only generate pins, and this could result in a pin-bias of morph frequencies in general and in small populations in particular. If the morphs have different niches, morph frequencies should be related to environmental factors, morphs might be spatially segregated, and morphological differences between morphs would be expected. We tested these hypotheses in the declining distylous P. veris. We studied morph frequencies in relation to environmental conditions and population size, spatial segregation in field populations, morphological differences between morphs, and growth responses to nutrient addition. Morph frequencies in 76 populations with 1 - 80000 flowering plants fluctuated symmetrically about 50 %. Deviations from 50 % were much larger in small populations, and sixof the smallest populations had lost one morph altogether. In contrast, morph frequencies were neither related to population size nor to 17 measures of environmental conditions. We found no spatial segregation or morphological differences in the field or in the common garden. The results suggest that demographic stochasticity caused deviations of the morph ratiofrom unity in small populations. Demographic stochasticity was probably caused by the random elimination of plants during the fragmentation of formerly large continuous populations. Biased morph frequencies may be one of the reasons for the strongly reduced reproduction in small populations of P. veris.

SU-E-J-22: A Feasibility Study On KV-Based Whole Breast Radiation Patient Setup

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

Huang, Q; Zhang, M; Yue, N

Purpose: In room kilovoltage x-ray (kV) imaging provides higher contrast than Megavoltage (MV) imaging with faster acquisition time compared with on-board cone-beam computed tomography (CBCT), thus improving patient setup accuracy and efficiency. In this study we evaluated the clinical feasibility of utilizing kV imaging for whole breast radiation patient setup. Methods: For six breast cancer patients with whole breast treatment plans using two opposed tangential fields, MV-based patient setup was conducted by aligning patient markers with in room lasers and MV portal images. Beam-eye viewed kV images were acquired using Varian OBI system after the set up process. In housemore » software was developed to transfer MLC blocks information overlaying onto kV images to demonstrate the field shape for verification. KV-based patient digital shift was derived by performing rigid registration between kV image and the digitally reconstructed radiography (DRR) to align the bony structure. This digital shift between kV-based and MV-based setup was defined as setup deviation. Results: Six sets of kV images were acquired for breast patients. The mean setup deviation was 2.3mm, 2.2mm and 1.8mm for anterior-posterior, superior-inferior and left-right direction respectively. The average setup deviation magnitude was 4.3±1.7mm for six patients. Patient with large breast had a larger setup deviation (4.4–6.2mm). There was no strong correlation between MV-based shift and setup deviation. Conclusion: A preliminary clinical workflow for kV-based whole breast radiation setup was established and tested. We observed setup deviation of the magnitude below than 5mm. With the benefit of providing higher contrast and MLC block overlaid on the images for treatment field verification, it is feasible to use kV imaging for breast patient setup.« less

Use of a Binocular Optical Coherence Tomography System to Evaluate Strabismus in Primary Position.

PubMed

Chopra, Reena; Mulholland, Pádraig J; Tailor, Vijay K; Anderson, Roger S; Keane, Pearse A

2018-05-31

Current clinical methods for assessing strabismus can be prone to error. Binocular optical coherence tomography (OCT) has the potential to assess and quantify strabismus objectively and in an automated manner. To evaluate the use of a binocular OCT prototype to assess the presence and size of strabismus. Fifteen participants with strabismus were recruited in 2016 as part of the EASE study from Moorfields Eye Hospital National Health Service Foundation Trust, London, England, and 15 healthy volunteers underwent automated anterior segment imaging using the binocular OCT prototype. All participants had an orthoptic assessment, including alternating prism cover test (APCT), before undergoing imaging. Simultaneously acquired pairs of OCT images, captured with 1 eye fixating, were analyzed using ImageJ (National Institutes of Health) to assess the presence and angle of strabismus. The direction and size of strabismus measured using binocular OCT was compared with that found using APCT. The median age for participants with strabismus was 55 years (interquartile range [IQR], 33-66.5 years) and for the healthy group, 50 years (IQR, 41-59 years); 15 participants (50%) were women, and 25 participants (83.3%) were white. The median magnitude of horizontal deviation was 20∆ (IQR, 13-35∆) and for vertical deviation, 3∆ (IQR, 0-5∆). Binocular OCT imaging correctly revealed the type and direction of the deviation in all 15 participants with strabismus, including horizontal and vertical deviations. The APCT and OCT measurements were strongly correlated for the horizontal (Pearson r = 0.85; 95% CI, 0.60-0.95; P < .001) and vertical (r = 0.89; 95% CI, 0.69-0.96; P < .001) deviations. In the healthy cohort, 9 of 15 participants (60%) had a latent horizontal deviation on APCT results (median magnitude 2∆, range 2-4∆). Six (40%) had orthophoria. Horizontal deviations were observed on OCT imaging results in 12 of the 15 participants (80%), and a vertical deviation was visible in 1 participant (6.7%). These findings suggest that binocular anterior segment OCT imaging can provide clinicians with a precise measurement of strabismus. The prototype can potentially incorporate several binocular vision tests that will provide quantitative data for the assessment, diagnosis, and monitoring of ocular misalignments.

Nonlocal rheological properties of granular flows near a jamming limit.

PubMed

Aranson, Igor S; Tsimring, Lev S; Malloggi, Florent; Clément, Eric

2008-09-01

We study the rheology of sheared granular flows close to a jamming transition. We use the approach of partially fluidized theory (PFT) with a full set of equations extending the thin layer approximation derived previously for the description of the granular avalanches phenomenology. This theory provides a picture compatible with a local rheology at large shear rates [G. D. R. Midi, Eur. Phys. J. E 14, 341 (2004)] and it works in the vicinity of the jamming transition, where a description in terms of a simple local rheology comes short. We investigate two situations displaying important deviations from local rheology. The first one is based on a set of numerical simulations of sheared soft two-dimensional circular grains. The next case describes previous experimental results obtained on avalanches of sandy material flowing down an incline. Both cases display, close to jamming, significant deviations from the now standard Pouliquen's flow rule [O. Pouliquen, Phys. Fluids 11, 542 (1999); 11, 1956 (1999)]. This discrepancy is the hallmark of a strongly nonlocal rheology and in both cases, we relate the empirical results and the outcomes of PFT. The numerical simulations show a characteristic constitutive structure for the fluid part of the stress involving the confining pressure and the material stiffness that appear in the form of an additional dimensionless parameter. This constitutive relation is then used to describe the case of sandy flows. We show a quantitative agreement as far as the effective flow rules are concerned. A fundamental feature is identified in PFT as the existence of a jammed layer developing in the vicinity of the flow arrest that corroborates the experimental findings. Finally, we study the case of solitary erosive granular avalanches and relate the outcome with the PFT analysis.

Effects of chemical composition on the corrosion of dental alloys.

PubMed

Galo, Rodrigo; Ribeiro, Ricardo Faria; Rodrigues, Renata Cristina Silveira; Rocha, Luís Augusto; de Mattos, Maria da Glória Chiarello

2012-01-01

The aim of this study was to determine the effect of the oral environment on the corrosion of dental alloys with different compositions, using electrochemical methods. The corrosion rates were obtained from the current-potential curves and electrochemical impedance spectroscopy (EIS). The effect of artificial saliva on the corrosion of dental alloys was dependent on alloy composition. Dissolution of the ions occurred in all tested dental alloys and the results were strongly dependent on the general alloy composition. Regarding the alloys containing nickel, the Ni-Cr and Ni-Cr-Ti alloys released 0.62 mg/L of Ni on average, while the Co-Cr dental alloy released ions between 0.01 and 0.03 mg/L of Co and Cr, respectively.The open-circuit potential stabilized at a higher level with lower deviation (standard deviation: Ni-Cr-6Ti = 32 mV/SCE and Co-Cr = 54 mV/SCE). The potenciodynamic curves of the dental alloys showed that the Ni-based dental alloy with >70 wt% of Ni had a similar curve and the Co-Cr dental alloy showed a low current density and hence a high resistance to corrosion compared with the Ni-based dental alloys. Some changes in microstructure were observed and this fact influenced the corrosion behavior for the alloys. The lower corrosion resistance also led to greater release of nickel ions to the medium. The quantity of Co ions released from the Co-Cr-Mo alloy was relatively small in the solutions. In addition, the quantity of Cr ions released into the artificial saliva from the Co-Cr alloy was lower than Cr release from the Ni-based dental alloys.

Characteristics of Turbulent Transfer during Episodes of Heavy Haze Pollution in Beijing in Winter 2016/17

NASA Astrophysics Data System (ADS)

Ren, Yan; Zheng, Shuwen; Wei, Wei; Wu, Bingui; Zhang, Hongsheng; Cai, Xuhui; Song, Yu

2018-02-01

We analyzed the structure and evolution of turbulent transfer and the wind profile in the atmospheric boundary layer in relation to aerosol concentrations during an episode of heavy haze pollution from 6 December 2016 to 9 January 2017. The turbulence data were recorded at Peking University's atmospheric science and environment observation station. The results showed a negative correlation between the wind speed and the PM2.5 concentration. The turbulence kinetic energy was large and showed obvious diurnal variations during unpolluted (clean) weather, but was small during episodes of heavy haze pollution. Under both clean and heavy haze conditions, the relation between the non-dimensional wind components and the stability parameter z/ L followed a 1/3 power law, but the normalized standard deviations of the wind speed were smaller during heavy pollution events than during clean periods under near-neutral conditions. Under unstable conditions, the normalized standard deviation of the potential temperature σ θ /| θ *| was related to z/ L, roughly following a -1/3 power law, and the ratio during pollution days was greater than that during clean days. The three-dimensional turbulence energy spectra satisfied a -2/3 power exponent rate in the high-frequency band. In the low-frequency band, the wind velocity spectrum curve was related to the stability parameters under clear conditions, but was not related to atmospheric stratification under polluted conditions. In the dissipation stage of the heavy pollution episode, the horizontal wind speed first started to increase at high altitudes and then gradually decreased at lower altitudes. The strong upward motion during this stage was an important dynamic factor in the dissipation of the heavy haze.

SWIFT-BAT HARD X-RAY SKY MONITORING UNVEILS THE ORBITAL PERIOD OF THE HMXB IGR J18219–1347

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

La Parola, V.; Cusumano, G.; Segreto, A.

2013-09-20

IGR J18219–1347 is a hard X-ray source discovered by INTEGRAL in 2010. We have analyzed the X-ray emission of this source exploiting the Burst Alert Telescope (BAT) survey data up to 2012 March and the X-Ray Telescope (XRT) data that include also an observing campaign performed in early 2012. The source is detected at a significance level of ∼13 standard deviations in the 88 month BAT survey data, and shows a strong variability along the survey monitoring, going from high intensity to quiescent states. A timing analysis on the BAT data revealed an intensity modulation with a period of Pmore » {sub 0} = 72.44 ± 0.3 days. The significance of this modulation is about seven standard deviations in Gaussian statistics. We interpret it as the orbital period of the binary system. The light curve folded at P {sub 0} shows a sharp peak covering ∼30% of the period, superimposed to a flat level roughly consistent with zero. In the soft X-rays the source is detected only in 5 out of 12 XRT observations, with the highest recorded count rate corresponding to a phase close to the BAT folded light-curve peak. The long orbital period and the evidence that the source emits only during a small fraction of the orbit suggests that the IGR J18219–1347 binary system hosts a Be star. The broadband XRT+BAT spectrum is well modeled with a flat absorbed power law with a high-energy exponential cutoff at ∼11 keV.« less

Excitations in the Yang–Gaudin Bose gas

DOE PAGES

Robinson, Neil J.; Konik, Robert M.

2017-06-01

Here, we study the excitation spectrum of two-component delta-function interacting bosons confined to a single spatial dimension, the Yang–Gaudin Bose gas. We show that there are pronounced finite-size effects in the dispersion relations of excitations, perhaps best illustrated by the spinon single particle dispersion which exhibits a gap at 2k F and a finite-momentum roton-like minimum. Such features occur at energies far above the finite volume excitation gap, vanish slowly as 1/L for fixed spinon number, and can persist to the thermodynamic limit at fixed spinon density. Features such as the 2k F gap also persist to multi-particle excitation continua. Our results show that excitations in the finite system can behave in a qualitatively different manner to analogous excitations in the thermodynamic limit. The Yang–Gaudin Bose gas is also host to multi-spinon bound states, known asmore » $$\\Lambda$$ -strings. We study these excitations both in the thermodynamic limit under the string hypothesis and in finite size systems where string deviations are taken into account. In the zero-temperature limit we present a simple relation between the length n $$\\Lambda$$-string dressed energies $$\\epsilon_n(\\lambda)$$ and the dressed energy $$\\epsilon(k)$$. We solve the Yang–Yang–Takahashi equations numerically and compare to the analytical solution obtained under the strong couple expansion, revealing that the length n $$\\Lambda$$ -string dressed energy is Lorentzian over a wide range of real string centers λ in the vicinity of $$\\lambda = 0$$ . We then examine the finite size effects present in the dispersion of the two-spinon bound states by numerically solving the Bethe ansatz equations with string deviations.« less

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

Robinson, Neil J.; Konik, Robert M.

Here, we study the excitation spectrum of two-component delta-function interacting bosons confined to a single spatial dimension, the Yang–Gaudin Bose gas. We show that there are pronounced finite-size effects in the dispersion relations of excitations, perhaps best illustrated by the spinon single particle dispersion which exhibits a gap at 2k F and a finite-momentum roton-like minimum. Such features occur at energies far above the finite volume excitation gap, vanish slowly as 1/L for fixed spinon number, and can persist to the thermodynamic limit at fixed spinon density. Features such as the 2k F gap also persist to multi-particle excitation continua. Our results show that excitations in the finite system can behave in a qualitatively different manner to analogous excitations in the thermodynamic limit. The Yang–Gaudin Bose gas is also host to multi-spinon bound states, known asmore » $$\\Lambda$$ -strings. We study these excitations both in the thermodynamic limit under the string hypothesis and in finite size systems where string deviations are taken into account. In the zero-temperature limit we present a simple relation between the length n $$\\Lambda$$-string dressed energies $$\\epsilon_n(\\lambda)$$ and the dressed energy $$\\epsilon(k)$$. We solve the Yang–Yang–Takahashi equations numerically and compare to the analytical solution obtained under the strong couple expansion, revealing that the length n $$\\Lambda$$ -string dressed energy is Lorentzian over a wide range of real string centers λ in the vicinity of $$\\lambda = 0$$ . We then examine the finite size effects present in the dispersion of the two-spinon bound states by numerically solving the Bethe ansatz equations with string deviations.« less

Finite difference modelling of dipole acoustic logs in a poroelastic formation with anisotropic permeability

NASA Astrophysics Data System (ADS)

He, Xiao; Hu, Hengshan; Wang, Xiuming

2013-01-01

Sedimentary rocks can exhibit strong permeability anisotropy due to layering, pre-stresses and the presence of aligned microcracks or fractures. In this paper, we develop a modified cylindrical finite-difference algorithm to simulate the borehole acoustic wavefield in a saturated poroelastic medium with transverse isotropy of permeability and tortuosity. A linear interpolation process is proposed to guarantee the leapfrog finite difference scheme for the generalized dynamic equations and Darcy's law for anisotropic porous media. First, the modified algorithm is validated by comparison against the analytical solution when the borehole axis is parallel to the symmetry axis of the formation. The same algorithm is then used to numerically model the dipole acoustic log in a borehole with its axis being arbitrarily deviated from the symmetry axis of transverse isotropy. The simulation results show that the amplitudes of flexural modes vary with the dipole orientation because the permeability tensor of the formation is dependent on the wellbore azimuth. It is revealed that the attenuation of the flexural wave increases approximately linearly with the radial permeability component in the direction of the transmitting dipole. Particularly, when the borehole axis is perpendicular to the symmetry axis of the formation, it is possible to estimate the anisotropy of permeability by evaluating attenuation of the flexural wave using a cross-dipole sonic logging tool according to the results of sensitivity analyses. Finally, the dipole sonic logs in a deviated borehole surrounded by a stratified porous formation are modelled using the proposed finite difference code. Numerical results show that the arrivals and amplitudes of transmitted flexural modes near the layer interface are sensitive to the wellbore inclination.

Comparing the Pearson and Spearman correlation coefficients across distributions and sample sizes: A tutorial using simulations and empirical data.

PubMed

de Winter, Joost C F; Gosling, Samuel D; Potter, Jeff

2016-09-01

The Pearson product–moment correlation coefficient ( r p ) and the Spearman rank correlation coefficient ( r s ) are widely used in psychological research. We compare r p and r s on 3 criteria: variability, bias with respect to the population value, and robustness to an outlier. Using simulations across low (N = 5) to high (N = 1,000) sample sizes we show that, for normally distributed variables, r p and r s have similar expected values but r s is more variable, especially when the correlation is strong. However, when the variables have high kurtosis, r p is more variable than r s . Next, we conducted a sampling study of a psychometric dataset featuring symmetrically distributed data with light tails, and of 2 Likert-type survey datasets, 1 with light-tailed and the other with heavy-tailed distributions. Consistent with the simulations, r p had lower variability than r s in the psychometric dataset. In the survey datasets with heavy-tailed variables in particular, r s had lower variability than r p , and often corresponded more accurately to the population Pearson correlation coefficient ( R p ) than r p did. The simulations and the sampling studies showed that variability in terms of standard deviations can be reduced by about 20% by choosing r s instead of r p . In comparison, increasing the sample size by a factor of 2 results in a 41% reduction of the standard deviations of r s and r p . In conclusion, r p is suitable for light-tailed distributions, whereas r s is preferable when variables feature heavy-tailed distributions or when outliers are present, as is often the case in psychological research. PsycINFO Database Record (c) 2016 APA, all rights reserved

Non-local rheological properties of granular flows near a jamming limit.

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

Aranson, I. S.; Tsimring, L. S.; Malloggi, F.

2008-01-01

We study the rheology of sheared granular flows close to a jamming transition. We use the approach of partially fluidized theory (PFT) with a full set of equations extending the thin layer approximation derived previously for the description of the granular avalanches phenomenology. This theory provides a picture compatible with a local rheology at large shear rates [G. D. R. Midi, Eur. Phys. J. E 14, 341 (2004)] and it works in the vicinity of the jamming transition, where a description in terms of a simple local rheology comes short. We investigate two situations displaying important deviations from local rheology.more » The first one is based on a set of numerical simulations of sheared soft two-dimensional circular grains. The next case describes previous experimental results obtained on avalanches of sandy material flowing down an incline. Both cases display, close to jamming, significant deviations from the now standard Pouliquen's flow rule [O. Pouliquen, Phys. Fluids 11, 542 (1999); 11, 1956 (1999)]. This discrepancy is the hallmark of a strongly nonlocal rheology and in both cases, we relate the empirical results and the outcomes of PFT. The numerical simulations show a characteristic constitutive structure for the fluid part of the stress involving the confining pressure and the material stiffness that appear in the form of an additional dimensionless parameter. This constitutive relation is then used to describe the case of sandy flows. We show a quantitative agreement as far as the effective flow rules are concerned. A fundamental feature is identified in PFT as the existence of a jammed layer developing in the vicinity of the flow arrest that corroborates the experimental findings. Finally, we study the case of solitary erosive granular avalanches and relate the outcome with the PFT analysis.« less

The influence of image sensor irradiation damage on the tracking and pointing accuracy of optical communication system

NASA Astrophysics Data System (ADS)

Li, Xiaoliang; Luo, Lei; Li, Pengwei; Yu, Qingkui

2018-03-01

The image sensor in satellite optical communication system may generate noise due to space irradiation damage, leading to deviation for the determination of the light spot centroid. Based on the irradiation test data of CMOS devices, simulated defect spots in different sizes have been used for calculating the centroid deviation value by grey-level centroid algorithm. The impact on tracking & pointing accuracy of the system has been analyzed. The results show that both the amount and the position of irradiation-induced defect pixels contribute to spot centroid deviation. And the larger spot has less deviation. At last, considering the space radiation damage, suggestions are made for the constraints of spot size selection.

Reliable detection of fluence anomalies in EPID-based IMRT pretreatment quality assurance using pixel intensity deviations

PubMed Central

Gordon, J. J.; Gardner, J. K.; Wang, S.; Siebers, J. V.

2012-01-01

Purpose: This work uses repeat images of intensity modulated radiation therapy (IMRT) fields to quantify fluence anomalies (i.e., delivery errors) that can be reliably detected in electronic portal images used for IMRT pretreatment quality assurance. Methods: Repeat images of 11 clinical IMRT fields are acquired on a Varian Trilogy linear accelerator at energies of 6 MV and 18 MV. Acquired images are corrected for output variations and registered to minimize the impact of linear accelerator and electronic portal imaging device (EPID) positioning deviations. Detection studies are performed in which rectangular anomalies of various sizes are inserted into the images. The performance of detection strategies based on pixel intensity deviations (PIDs) and gamma indices is evaluated using receiver operating characteristic analysis. Results: Residual differences between registered images are due to interfraction positional deviations of jaws and multileaf collimator leaves, plus imager noise. Positional deviations produce large intensity differences that degrade anomaly detection. Gradient effects are suppressed in PIDs using gradient scaling. Background noise is suppressed using median filtering. In the majority of images, PID-based detection strategies can reliably detect fluence anomalies of ≥5% in ∼1 mm2 areas and ≥2% in ∼20 mm2 areas. Conclusions: The ability to detect small dose differences (≤2%) depends strongly on the level of background noise. This in turn depends on the accuracy of image registration, the quality of the reference image, and field properties. The longer term aim of this work is to develop accurate and reliable methods of detecting IMRT delivery errors and variations. The ability to resolve small anomalies will allow the accuracy of advanced treatment techniques, such as image guided, adaptive, and arc therapies, to be quantified. PMID:22894421

External K+ dependence of strong inward rectifier K+ channel conductance is caused not by K+ but by competitive pore blockade by external Na.

PubMed

Ishihara, Keiko

2018-06-15

Strong inward rectifier K + (sKir) channels determine the membrane potentials of many types of excitable and nonexcitable cells, most notably the resting potentials of cardiac myocytes. They show little outward current during membrane depolarization (i.e., strong inward rectification) because of the channel blockade by cytoplasmic polyamines, which depends on the deviation of the membrane potential from the K + equilibrium potential ( V - E K ) when the extracellular K + concentration ([K + ] out ) is changed. Because their open - channel conductance is apparently proportional to the "square root" of [K + ] out , increases/decreases in [K + ] out enhance/diminish outward currents through sKir channels at membrane potentials near their reversal potential, which also affects, for example, the repolarization and action-potential duration of cardiac myocytes. Despite its importance, however, the mechanism underlying the [K + ] out dependence of the open sKir channel conductance has remained elusive. By studying Kir2.1, the canonical member of the sKir channel family, we first show that the outward currents of Kir2.1 are observed under the external K + -free condition when its inward rectification is reduced and that the complete inhibition of the currents at 0 [K + ] out results solely from pore blockade caused by the polyamines. Moreover, the noted square-root proportionality of the open sKir channel conductance to [K + ] out is mediated by the pore blockade by the external Na + , which is competitive with the external K + Our results show that external K + itself does not activate or facilitate K + permeation through the open sKir channel to mediate the apparent external K + dependence of its open channel conductance. The paradoxical increase/decrease in outward sKir channel currents during alternations in [K + ] out , which is physiologically relevant, is caused by competition from impermeant extracellular Na . © 2018 Ishihara.

Percentage depth dose calculation accuracy of model based algorithms in high energy photon small fields through heterogeneous media and comparison with plastic scintillator dosimetry

PubMed Central

Mani, Ganesh Kadirampatti; Karunakaran, Kaviarasu

2016-01-01

Small fields smaller than 4×4 cm2 are used in stereotactic and conformal treatments where heterogeneity is normally present. Since dose calculation accuracy in both small fields and heterogeneity often involves more discrepancy, algorithms used by treatment planning systems (TPS) should be evaluated for achieving better treatment results. This report aims at evaluating accuracy of four model‐based algorithms, X‐ray Voxel Monte Carlo (XVMC) from Monaco, Superposition (SP) from CMS‐Xio, AcurosXB (AXB) and analytical anisotropic algorithm (AAA) from Eclipse are tested against the measurement. Measurements are done using Exradin W1 plastic scintillator in Solid Water phantom with heterogeneities like air, lung, bone, and aluminum, irradiated with 6 and 15 MV photons of square field size ranging from 1 to 4 cm2. Each heterogeneity is introduced individually at two different depths from depth‐of‐dose maximum (Dmax), one setup being nearer and another farther from the Dmax. The central axis percentage depth‐dose (CADD) curve for each setup is measured separately and compared with the TPS algorithm calculated for the same setup. The percentage normalized root mean squared deviation (%NRMSD) is calculated, which represents the whole CADD curve's deviation against the measured. It is found that for air and lung heterogeneity, for both 6 and 15 MV, all algorithms show maximum deviation for field size 1×1 cm2 and gradually reduce when field size increases, except for AAA. For aluminum and bone, all algorithms' deviations are less for 15 MV irrespective of setup. In all heterogeneity setups, 1×1 cm2 field showed maximum deviation, except in 6 MV bone setup. All algorithms in the study, irrespective of energy and field size, when any heterogeneity is nearer to Dmax, the dose deviation is higher compared to the same heterogeneity far from the Dmax. Also, all algorithms show maximum deviation in lower‐density materials compared to high‐density materials. PACS numbers: 87.53.Bn, 87.53.kn, 87.56.bd, 87.55.Kd, 87.56.jf PMID:26894345

Seismic velocity deviation log: An effective method for evaluating spatial distribution of reservoir pore types

NASA Astrophysics Data System (ADS)

Shirmohamadi, Mohamad; Kadkhodaie, Ali; Rahimpour-Bonab, Hossain; Faraji, Mohammad Ali

2017-04-01

Velocity deviation log (VDL) is a synthetic log used to determine pore types in reservoir rocks based on a combination of the sonic log with neutron-density logs. The current study proposes a two step approach to create a map of porosity and pore types by integrating the results of petrographic studies, well logs and seismic data. In the first step, velocity deviation log was created from the combination of the sonic log with the neutron-density log. The results allowed identifying negative, zero and positive deviations based on the created synthetic velocity log. Negative velocity deviations (below - 500 m/s) indicate connected or interconnected pores and fractures, while positive deviations (above + 500 m/s) are related to isolated pores. Zero deviations in the range of [- 500 m/s, + 500 m/s] are in good agreement with intercrystalline and microporosities. The results of petrographic studies were used to validate the main pore type derived from velocity deviation log. In the next step, velocity deviation log was estimated from seismic data by using a probabilistic neural network model. For this purpose, the inverted acoustic impedance along with the amplitude based seismic attributes were formulated to VDL. The methodology is illustrated by performing a case study from the Hendijan oilfield, northwestern Persian Gulf. The results of this study show that integration of petrographic, well logs and seismic attributes is an instrumental way for understanding the spatial distribution of main reservoir pore types.

Perception of midline deviations in smile esthetics by laypersons.

PubMed

Ferreira, Jamille Barros; Silva, Licínio Esmeraldo da; Caetano, Márcia Tereza de Oliveira; Motta, Andrea Fonseca Jardim da; Cury-Saramago, Adriana de Alcantara; Mucha, José Nelson

2016-01-01

To evaluate the esthetic perception of upper dental midline deviation by laypersons and if adjacent structures influence their judgment. An album with 12 randomly distributed frontal view photographs of the smile of a woman with the midline digitally deviated was evaluated by 95 laypersons. The frontal view smiling photograph was modified to create from 1 mm to 5 mm deviations in the upper midline to the left side. The photographs were cropped in two different manners and divided into two groups of six photographs each: group LCN included the lips, chin, and two-thirds of the nose, and group L included the lips only. The laypersons performed the rate of each smile using a visual analog scale (VAS). Wilcoxon test, Student's t-test and Mann-Whitney test were applied, adopting a 5% level of significance. Laypersons were able to perceive midline deviations starting at 1 mm. Statistically significant results (p< 0.05) were found for all multiple comparisons of the values in photographs of group LCN and for almost all comparisons in photographs of group L. Comparisons between the photographs of groups LCN and L showed statistically significant values (p< 0.05) when the deviation was 1 mm. Laypersons were able to perceive the upper dental midline deviations of 1 mm, and above when the adjacent structures of the smiles were included. Deviations of 2 mm and above when the lips only were included. The visualization of structures adjacent to the smile demonstrated influence on the perception of midline deviation.

Sulfide Melts and Chalcophile Element Behavior in High Temperature Systems

NASA Astrophysics Data System (ADS)

Wood, B. J.; Kiseeva, K.

2016-12-01

We recently found that partition coefficients (Di) of many weakly and moderately chalcophile elements (e.g., Cd, Zn, Co, Cr, Pb, Sb, In) between sulfide and silicate melts are simple functions of the FeO content of the silicate liquid: logDi A-Blog[FeO] where [FeO] is the FeO concentration in the silicate, A and B are constants and the latter is related to the valency of the element of interest. In contrast, some strongly chalcophile (e.g Cu, Ni, Ag) and lithophile elements (e.g Mn) show marked deviations from linearity on a plot of logDi vs log[FeO]. More recent experiments show that linear behavior is confined to elements whose affinities for S and O are similar to those of Fe. In the case of elements more strongly lithophile than Fe (Ti, U, REE, Zr, Nb, Ta, Mn) a plot of logDi versus log[FeO] describes a U-shape with the element partitioning strongly into the sulfide at very low FeO and again at very high FeO content of the silicate melt. In contrast, strongly chalcophile elements (Cu, Ni, Ag) describe an n-shape on the plot of logD vs log[FeO]. The result is that lithophile elements such as Nb become more "chalcophile" than Cu at very low and very high FeO contents of the silicate melt. The reasons for this surprising behavior are firstly that, at very low FeO contents the silicate melt dissolves substantial amounts of sulfur, which drives down the activity of FeO and, from mass-action "pulls" the lihophile element into the sulfide. At high FeO contents of the silicate the sulfide itself starts to dissolve substantial amounts of oxygen and lithophile elements follow the oxygen into the sulfide. Given the principles which we have established, we are able to describe the patterns of chalcophile element behavior during partial melting and fractional crystallisation on Earth and also on bodies such as Mercury and Mars which are, respectively, strongly reduced relative to Earth and more oxidised than Earth.

A critical assessment of two types of personal UV dosimeters.

PubMed

Seckmeyer, Gunther; Klingebiel, Marcus; Riechelmann, Stefan; Lohse, Insa; McKenzie, Richard L; Liley, J Ben; Allen, Martin W; Siani, Anna-Maria; Casale, Giuseppe R

2012-01-01

Doses of erythemally weighted irradiances derived from polysulphone (PS) and electronic ultraviolet (EUV) dosimeters have been compared with measurements obtained using a reference spectroradiometer. PS dosimeters showed mean absolute deviations of 26% with a maximum deviation of 44%, the calibrated EUV dosimeters showed mean absolute deviations of 15% (maximum 33%) around noon during several test days in the northern hemisphere autumn. In the case of EUV dosimeters, measurements with various cut-off filters showed that part of the deviation from the CIE erythema action spectrum was due to a small, but significant sensitivity to visible radiation that varies between devices and which may be avoided by careful preselection. Usually the method of calibrating UV sensors by direct comparison to a reference instrument leads to reliable results. However, in some circumstances the quality of measurements made with simple sensors may be over-estimated. In the extreme case, a simple pyranometer can be used as a UV instrument, providing acceptable results for cloudless skies, but very poor results under cloudy conditions. It is concluded that while UV dosimeters are useful for their design purpose, namely to estimate personal UV exposures, they should not be regarded as an inexpensive replacement for meteorological grade instruments. © 2011 Wiley Periodicals, Inc. Photochemistry and Photobiology © 2011 The American Society of Photobiology.

Self-optimizing Pitch Control for Large Scale Wind Turbine Based on ADRC

NASA Astrophysics Data System (ADS)

Xia, Anjun; Hu, Guoqing; Li, Zheng; Huang, Dongxiao; Wang, Fengxiang

2018-01-01

Since wind turbine is a complex nonlinear and strong coupling system, traditional PI control method can hardly achieve good control performance. A self-optimizing pitch control method based on the active-disturbance-rejection control theory is proposed in this paper. A linear model of the wind turbine is derived by linearizing the aerodynamic torque equation and the dynamic response of wind turbine is transformed into a first-order linear system. An expert system is designed to optimize the amplification coefficient according to the pitch rate and the speed deviation. The purpose of the proposed control method is to regulate the amplification coefficient automatically and keep the variations of pitch rate and rotor speed in proper ranges. Simulation results show that the proposed pitch control method has the ability to modify the amplification coefficient effectively, when it is not suitable, and keep the variations of pitch rate and rotor speed in proper ranges

From polariton condensates to highly photonic quantum degenerate states of bosonic matter

PubMed Central

Aßmann, Marc; Tempel, Jean-Sebastian; Veit, Franziska; Bayer, Manfred; Rahimi-Iman, Arash; Löffler, Andreas; Höfling, Sven; Reitzenstein, Stephan; Worschech, Lukas; Forchel, Alfred

2011-01-01

Bose–Einstein condensation (BEC) is a thermodynamic phase transition of an interacting Bose gas. Its key signatures are remarkable quantum effects like superfluidity and a phonon-like Bogoliubov excitation spectrum, which have been verified for atomic BECs. In the solid state, BEC of exciton–polaritons has been reported. Polaritons are strongly coupled light-matter quasiparticles in semiconductor microcavities and composite bosons. However, they are subject to dephasing and decay and need external pumping to reach a steady state. Accordingly the polariton BEC is a nonequilibrium process of a degenerate polariton gas in self-equilibrium, but out of equilibrium with the baths it is coupled to and therefore deviates from the thermodynamic phase transition seen in atomic BECs. Here we show that key signatures of BEC can even be observed without fulfilling the self-equilibrium condition in a highly photonic quantum degenerate nonequilibrium system. PMID:21245353

Connectedness percolation of hard deformed rods

NASA Astrophysics Data System (ADS)

Drwenski, Tara; Dussi, Simone; Dijkstra, Marjolein; van Roij, René; van der Schoot, Paul

2017-12-01

Nanofiller particles, such as carbon nanotubes or metal wires, are used in functional polymer composites to make them conduct electricity. They are often not perfectly straight cylinders but may be tortuous or exhibit kinks. Therefore we investigate the effect of shape deformations of the rod-like nanofillers on the geometric percolation threshold of the dispersion. We do this by using connectedness percolation theory within a Parsons-Lee type of approximation, in combination with Monte Carlo integration for the average overlap volume in the isotropic fluid phase. We find that a deviation from a perfect rod-like shape has very little effect on the percolation threshold, unless the particles are strongly deformed. This demonstrates that idealized rod models are useful even for nanofillers that superficially seem imperfect. In addition, we show that for small or moderate rod deformations, the universal scaling of the percolation threshold is only weakly affected by the precise particle shape.

Conserved charge fluctuations at vanishing and non-vanishing chemical potential

NASA Astrophysics Data System (ADS)

Karsch, Frithjof

2017-11-01

Up to 6th order cumulants of fluctuations of net baryon-number, net electric charge and net strangeness as well as correlations among these conserved charge fluctuations are now being calculated in lattice QCD. These cumulants provide a wealth of information on the properties of strong-interaction matter in the transition region from the low temperature hadronic phase to the quark-gluon plasma phase. They can be used to quantify deviations from hadron resonance gas (HRG) model calculations which frequently are used to determine thermal conditions realized in heavy ion collision experiments. Already some second order cumulants like the correlations between net baryon-number and net strangeness or net electric charge differ significantly at temperatures above 155 MeV in QCD and HRG model calculations. We show that these differences increase at non-zero baryon chemical potential constraining the applicability range of HRG model calculations to even smaller values of the temperature.

Short-range components of nuclear forces: Experiment versus mythology

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

Kukulin, V. I.; Platonova, M. N., E-mail: platonova@nucl-th.sinp.msu.ru

2013-12-15

The present-day situation around the description of various (central, spin-orbit, and tensor) components of short-range nuclear forces is discussed. A traditional picture of these interactions based on the idea of one-meson exchange is contrasted against numerous results of recent experiments. As is shown in the present study, these results often deviate strongly from the predictions of traditional models. One can therefore state that such models are inapplicable to describing short-range nuclear forces and that it is necessary to go over from a traditional description to some alternative QCD-based (or QCD-motivated) picture. This means that, despite the widespread popularity of traditionalmore » concepts of short-range nuclear forces and their applicability in many particular cases, these concepts are not more than scientific myths that show their inconsistency when analyzed from the viewpoint of the modern experiment.« less

Flare onset at sites of maximum magnetic shear

NASA Technical Reports Server (NTRS)

Hagyard, M. J.; Smith, J. B., Jr.

1988-01-01

Observations of the transverse component of the Sun's photospheric magnetic field obtained with the MSFC vector magnetograph show where the fields are nonpotential. The correlation was studied between locations of nonpotential fields and sites of flare onset for four different active regions. The details of the active region AR 4711 are outlined. Similar results are presented for three other regions: AR 2372 (April 1980), AR 2776 (November 1980), and AR 4474 (April 1984). For all four regions it is shown that flares initiate at sites on the magnetic neutral line where the local field deviates the most from the potential field. The results of this study suggest that flares are likely to erupt where the shear is equal to or greater than 85 degrees, the field is equal to or greater than 10000 G, and there is strong shear (equal to or greater then 80 degress) extending over a length equal to or greater than 8000 km.

Adaptation, Validation, Reliability and Factorial Equivalence of the Rosenberg Self-Esteem Scale in Colombian and Spanish Population.

PubMed

Gómez-Lugo, Mayra; Espada, José P; Morales, Alexandra; Marchal-Bertrand, Laurent; Soler, Franklin; Vallejo-Medina, Pablo

2016-10-14

The Rosenberg Self-Esteem Scale is the most widely used instrument to assess self-esteem. In light of the absence of adaptations in Colombia, this study seeks to validate and adapt this scale in the Colombian population, and perform factorial equivalence with the Spanish version. A total of 1,139 seniors (633 Colombians and 506 Spaniards) were evaluated; the individuals answered the Rosenberg Self-Esteem Scale and sexual self-esteem scale. The average score of the items was similar to the questionnaire's theoretical average, and standard deviations were close to one. The psychometric properties of the items are generally adequate with alphas of .83 and .86 and significant (CI = .95) and correlations with the sexual self-esteem scale ranging from .31 and .41. Factorial equivalence was confirmed by means of a structural equation model (CFI = .912 and RMSEA = .079), thus showing a strong level of invariance.

U(2)⁵ flavor symmetry and lepton universality violation in W→τν̄ τ

DOE PAGES

Filipuzzi, Alberto; Portolés, Jorge; González-Alonso, Martín

2012-06-26

The seeming violation of universality in the τ lepton coupling to the W boson suggested by LEP-II data is studied using an effective field theory (EFT) approach. Within this framework we explore how this feature fits into the current constraints from electroweak precision observables using different assumptions about the flavor structure of New Physics, namely [U(2)×U(1)]⁵ and U(2)⁵. We show the importance of leptonic and semileptonic tau decay measurements, giving 3–4 TeV bounds on the New Physics effective scale at 90% C.L. We conclude under very general assumptions that it is not possible to accommodate this deviation from universality inmore » the EFT framework, and thus such a signal could only be explained by the introduction of light degrees of freedom or New Physics strongly coupled at the electroweak scale.« less

Temporal Structure of Volatility Fluctuations

NASA Astrophysics Data System (ADS)

Wang, Fengzhong; Yamasaki, Kazuko; Stanley, H. Eugene; Havlin, Shlomo

Volatility fluctuations are of great importance for the study of financial markets, and the temporal structure is an essential feature of fluctuations. To explore the temporal structure, we employ a new approach based on the return interval, which is defined as the time interval between two successive volatility values that are above a given threshold. We find that the distribution of the return intervals follows a scaling law over a wide range of thresholds, and over a broad range of sampling intervals. Moreover, this scaling law is universal for stocks of different countries, for commodities, for interest rates, and for currencies. However, further and more detailed analysis of the return intervals shows some systematic deviations from the scaling law. We also demonstrate a significant memory effect in the return intervals time organization. We find that the distribution of return intervals is strongly related to the correlations in the volatility.

Laser radar cross-section estimation from high-resolution image data.

PubMed

Osche, G R; Seeber, K N; Lok, Y F; Young, D S

1992-05-10

A methodology for the estimation of ladar cross sections from high-resolution image data of geometrically complex targets is presented. Coherent CO(2) laser radar was used to generate high-resolution amplitude imagery of a UC-8 Buffalo test aircraft at a range of 1.3 km at nine different aspect angles. The average target ladar cross section was synthesized from these data and calculated to be sigma(T) = 15.4 dBsm, which is similar to the expected microwave radar cross sections. The aspect angle dependence of the cross section shows pronounced peaks at nose on and broadside, which are also in agreement with radar results. Strong variations in both the mean amplitude and the statistical distributions of amplitude with the aspect angle have also been observed. The relative mix of diffuse and specular returns causes significant deviations from a simple Lambertian or Swerling II target, especially at broadside where large normal surfaces are present.

Inferring Epidemic Contact Structure from Phylogenetic Trees

PubMed Central

Leventhal, Gabriel E.; Kouyos, Roger; Stadler, Tanja; von Wyl, Viktor; Yerly, Sabine; Böni, Jürg; Cellerai, Cristina; Klimkait, Thomas; Günthard, Huldrych F.; Bonhoeffer, Sebastian

2012-01-01

Contact structure is believed to have a large impact on epidemic spreading and consequently using networks to model such contact structure continues to gain interest in epidemiology. However, detailed knowledge of the exact contact structure underlying real epidemics is limited. Here we address the question whether the structure of the contact network leaves a detectable genetic fingerprint in the pathogen population. To this end we compare phylogenies generated by disease outbreaks in simulated populations with different types of contact networks. We find that the shape of these phylogenies strongly depends on contact structure. In particular, measures of tree imbalance allow us to quantify to what extent the contact structure underlying an epidemic deviates from a null model contact network and illustrate this in the case of random mixing. Using a phylogeny from the Swiss HIV epidemic, we show that this epidemic has a significantly more unbalanced tree than would be expected from random mixing. PMID:22412361

Finite-size effect on optimal efficiency of heat engines.

PubMed

Tajima, Hiroyasu; Hayashi, Masahito

2017-07-01

The optimal efficiency of quantum (or classical) heat engines whose heat baths are n-particle systems is given by the strong large deviation. We give the optimal work extraction process as a concrete energy-preserving unitary time evolution among the heat baths and the work storage. We show that our optimal work extraction turns the disordered energy of the heat baths to the ordered energy of the work storage, by evaluating the ratio of the entropy difference to the energy difference in the heat baths and the work storage, respectively. By comparing the statistical mechanical optimal efficiency with the macroscopic thermodynamic bound, we evaluate the accuracy of the macroscopic thermodynamics with finite-size heat baths from the statistical mechanical viewpoint. We also evaluate the quantum coherence effect on the optimal efficiency of the cycle processes without restricting their cycle time by comparing the classical and quantum optimal efficiencies.

Nanoscale arrays of antimony telluride single crystals by selective chemical vapor deposition

PubMed Central

Huang, Ruomeng; Benjamin, Sophie L.; Gurnani, Chitra; Wang, Yudong; Hector, Andrew L.; Levason, William; Reid, Gillian; De Groot, C. H. (Kees)

2016-01-01

Arrays of individual single nanocrystals of Sb2Te3 have been formed using selective chemical vapor deposition (CVD) from a single source precursor. Crystals are self-assembled reproducibly in confined spaces of 100 nm diameter with pitch down to 500 nm. The distribution of crystallite sizes across the arrays is very narrow (standard deviation of 15%) and is affected by both the hole diameter and the array pitch. The preferred growth of the crystals in the <1 1 0> orientation along the diagonal of the square holes strongly indicates that the diffusion of adatoms results in a near thermodynamic equilibrium growth mechanism of the nuclei. A clear relationship between electrical resistivity and selectivity is established across a range of metal selenides and tellurides, showing that conductive materials result in more selective growth and suggesting that electron donation is of critical importance for selective deposition. PMID:27283116

TLE uncertainty estimation using robust weighted differencing

NASA Astrophysics Data System (ADS)

Geul, Jacco; Mooij, Erwin; Noomen, Ron

2017-05-01

Accurate knowledge of satellite orbit errors is essential for many types of analyses. Unfortunately, for two-line elements (TLEs) this is not available. This paper presents a weighted differencing method using robust least-squares regression for estimating many important error characteristics. The method is applied to both classic and enhanced TLEs, compared to previous implementations, and validated using Global Positioning System (GPS) solutions for the GOCE satellite in Low-Earth Orbit (LEO), prior to its re-entry. The method is found to be more accurate than previous TLE differencing efforts in estimating initial uncertainty, as well as error growth. The method also proves more reliable and requires no data filtering (such as outlier removal). Sensitivity analysis shows a strong relationship between argument of latitude and covariance (standard deviations and correlations), which the method is able to approximate. Overall, the method proves accurate, computationally fast, and robust, and is applicable to any object in the satellite catalogue (SATCAT).

Revisiting the Marshmallow Test: A Conceptual Replication Investigating Links Between Early Delay of Gratification and Later Outcomes.

PubMed

Watts, Tyler W; Duncan, Greg J; Quan, Haonan

2018-05-01

We replicated and extended Shoda, Mischel, and Peake's (1990) famous marshmallow study, which showed strong bivariate correlations between a child's ability to delay gratification just before entering school and both adolescent achievement and socioemotional behaviors. Concentrating on children whose mothers had not completed college, we found that an additional minute waited at age 4 predicted a gain of approximately one tenth of a standard deviation in achievement at age 15. But this bivariate correlation was only half the size of those reported in the original studies and was reduced by two thirds in the presence of controls for family background, early cognitive ability, and the home environment. Most of the variation in adolescent achievement came from being able to wait at least 20 s. Associations between delay time and measures of behavioral outcomes at age 15 were much smaller and rarely statistically significant.

Field analyses of (238)U and (226)Ra in two uranium mill tailings piles from Niger using portable HPGe detector.

PubMed

Déjeant, Adrien; Bourva, Ludovic; Sia, Radia; Galoisy, Laurence; Calas, Georges; Phrommavanh, Vannapha; Descostes, Michael

2014-11-01

The radioactivities of (238)U and (226)Ra in mill tailings from the U mines of COMINAK and SOMAÏR in Niger were measured and quantified using a portable High-Purity Germanium (HPGe) detector. The (238)U and (226)Ra activities were measured under field conditions on drilling cores with 600s measurements and without any sample preparation. Field results were compared with those obtained by Inductive Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) and emanometry techniques. This comparison indicates that gamma-ray absorption by such geological samples does not cause significant deviations. This work shows the feasibility of using portable HPGe detector in the field as a preliminary method to observe variations of radionuclides concentration with the aim of identifying samples of interest. The HPGe is particularly useful for samples with strong secular disequilibrium such as mill tailings. Copyright © 2014 Elsevier Ltd. All rights reserved.

HF radar transmissions that deviate from great-circle paths: new insight from e-POP RRI

NASA Astrophysics Data System (ADS)

Perry, G. W.; Miller, E. S.; James, H. G.; Howarth, A. D.; St-Maurice, J. P.; Yau, A. W.

2016-12-01

Significant deviations of SuperDARN radar transmissions from their expected great-circle paths have been detected at ionospheric altitudes using the Radio Receiver Instrument (RRI) on the Enhanced Polar Outflow Probe (e-POP). Experiments between SuperDARN Rankin Inlet and e-POP RRI were conducted at similar local times over consecutive days. Customized experiment modes which incorporated the agile frequency switching capabilities of each system were used. The RRI measurements show deviations of radar transmissions from their expected paths by as much as 2 or 3 SuperDARN beam widths, equivalent to 6° - 10° in bearing from Rankin Inlet. The deviations displayed a dependence on the radar carrier frequency and a day-to-day variability, suggesting that the deviations were transient in nature. We will discuss the deviations in the context of 3D ray trace modeling and measurements from the Resolute Bay Incoherent Scatter Radar - North (RISR-N). The latter provided diagnostic information of the ionosphere along the ray path between RRI and Rankin Inlet during the experiments.

Temperature dependence of the LO phonon sidebands in free exciton emission of GaN

NASA Astrophysics Data System (ADS)

Xu, S. J.; Li, G. Q.; Xiong, S.-J.; Che, C. M.

2006-04-01

Temperature-dependent radiative recombination of free excitons involving one or two LO phonons in GaN is investigated in detail. It is found that both phonon sidebands possess asymmetric lineshapes and their energy spacings from the zero-phonon line strongly deviate from the characteristic energy of LO phonons as the temperature increases. Furthermore, the deviation rates of one- and two-phonon sidebands are significantly different. Segall-Mahan [Phys. Rev. 171, 935 (1968)] theory, taking the exciton-photon and exciton-phonon interactions into account, is employed to calculate the sidebands of one or two LO phonons for free excitons in a wide temperature range. Excellent agreement between the theory and experiment is achieved by using only one adjustable parameter, which leads to determination of the effective mass of heavy holes (~0.5m0).

Half-lives of 214Pb and 214Bi.

PubMed

Martz, D E; Langner, G H; Johnson, P R

1991-10-01

New measurements on chemically separated samples of 214Bi have yielded a mean half-life value of 19.71 +/- 0.02 min, where the error quoted is twice the standard deviation of the mean based on 23 decay runs. This result provides strong support for the historic 19.72 +/- 0.04 min half-life value and essentially excludes the 19.9-min value, both reported in previous studies. New measurements of the decay rate of 222Rn progeny activity initially in radioactive equilibrium have yielded a value of 26.89 +/- 0.03 min for the half-life of 214Pb, where the error quoted is twice the standard deviation of the mean based on 12 decay runs. This value is 0.1 min longer than the currently accepted 214Pb half-value of 26.8 min.

Statistical mechanics of light elements at high pressure. V Three-dimensional Thomas-Fermi-Dirac theory. [relevant to Jovian planetary interiors

NASA Technical Reports Server (NTRS)

Macfarlane, J. J.; Hubbard, W. B.

1983-01-01

A numerical technique for solving the Thomas-Fermi-Dirac (TED) equation in three dimensions, for an array of ions obeying periodic boundary conditions, is presented. The technique is then used to calculate deviations from ideal mixing for an alloy of hydrogen and helium at zero temperature and high presures. Results are compared with alternative models which apply perturbation theory to calculation of the electron distribution, based upon the assumption of weak response of the electron gas to the ions. The TFD theory, which permits strong electron response, always predicts smaller deviations from ideal mixing than would be predicted by perturbation theory. The results indicate that predicted phase separation curves for hydrogen-helium alloys under conditions prevailing in the metallic zones of Jupiter and Saturn are very model dependent.

Acoustic analysis of speech variables during depression and after improvement.

PubMed

Nilsonne, A

1987-09-01

Speech recordings were made of 16 depressed patients during depression and after clinical improvement. The recordings were analyzed using a computer program which extracts acoustic parameters from the fundamental frequency contour of the voice. The percent pause time, the standard deviation of the voice fundamental frequency distribution, the standard deviation of the rate of change of the voice fundamental frequency and the average speed of voice change were found to correlate to the clinical state of the patient. The mean fundamental frequency, the total reading time and the average rate of change of the voice fundamental frequency did not differ between the depressed and the improved group. The acoustic measures were more strongly correlated to the clinical state of the patient as measured by global depression scores than to single depressive symptoms such as retardation or agitation.

Regionally variant collagen alignment correlates with viscoelastic properties of the disc of the human temporomandibular joint.

PubMed

Gutman, Shawn; Kim, Daniel; Tarafder, Solaiman; Velez, Sergio; Jeong, Julia; Lee, Chang H

2018-02-01

To determine the regionally variant quality of collagen alignment in human TMJ discs and its statistical correlation with viscoelastic properties. For quantitative analysis of the quality of collagen alignment, horizontal sections of human TMJ discs with Pricrosirius Red staining were imaged under circularly polarized microscopy. Mean angle and angular deviation of collagen fibers in each region were analyzed using a well-established automated image-processing for angular gradient. Instantaneous and relaxation moduli of each disc region were measured under stress-relaxation test both in tensile and compression. Then Spearman correlation analysis was performed between the angular deviation and the moduli. To understand the effect of glycosaminoglycans on the correlation, TMJ disc samples were treated by chondroitinase ABC (C-ABC). Our imaging processing analysis showed the region-variant direction of collagen alignment, consistently with previous findings. Interestingly, the quality of collagen alignment, not only the directions, was significantly different in between the regions. The angular deviation of fiber alignment in the anterior and intermediate regions were significantly smaller than the posterior region. Medial and lateral regions showed significantly bigger angular deviation than all the other regions. The regionally variant angular deviation values showed statistically significant correlation with the tensile instantaneous modulus and the relaxation modulus, partially dependent on C-ABC treatment. Our findings suggest the region-variant degree of collagen fiber alignment is likely attributed to the heterogeneous viscoelastic properties of TMJ disc that may have significant implications in development of regenerative therapy for TMJ disc. Copyright © 2017 Elsevier Ltd. All rights reserved.

Local and regional species diversity of benthic Isopoda (Crustacea) in the deep Gulf of Mexico

NASA Astrophysics Data System (ADS)

Wilson, George D. F.

2008-12-01

Recent studies of deep-sea faunas considered the influence of mid-domain models in the distribution of species diversity and richness with depth. In this paper, I show that separating local diversity from regional species richness in benthic isopods clarifies mid-domain effects in the distribution of isopods in the Gulf of Mexico. Deviations from the randomised implied species ranges can be informative to understanding general patterns within the Gulf of Mexico. The isopods from the GoMB study contained 135 species, with a total of 156 species including those from an earlier study. More than 60 species may be new to science. Most families of deep-sea isopods (suborder Asellota) were present, although some were extremely rare. The isopod family Desmosomatidae dominated the samples, and one species of Macrostylis (Macrostylidae) was found in many samples. Species richness for samples pooled within sites ranged from 1 to 52 species. Because species in pooled samples were highly correlated with individuals, species diversity was compared across sites using the expected species estimator ( n=15 individuals, ES 15). Six depth transects had idiosyncratic patterns of ES 15, and transects with the greatest short-range variation in topography, such as basins and canyons, had the greatest short-range disparity. Basins on the deep slope did not have a consistent influence (i.e., relatively higher or lower than surrounding areas) on the comparative species diversity. ES 15 of all transects together showed a weak mid-domain effect, peaking around 1200-1500 m, with low values at the shallowest and deepest samples (Sigsbee Abyssal Plain); no longitudinal (east-west) pattern was found. The regional species pool was analyzed by summing the implied ranges of all species. The species ranges in aggregate did not have significant patterns across longitudes, and many species had broad depth ranges, suggesting that the isopod fauna of the Gulf of Mexico is well dispersed. The summed ranges, as expected, had strong mid-domain patterns, contrasting with the local species richness estimates. The longitudinal ranges closely matched a randomized pattern (species ranges placed randomly, 1000 iterations), with significant deviations in the east attributable to lower sampling effort. The depth pattern, however, deviated from the mid-domain model, with a bimodal peak displaced nearly 500 m shallower than the mode of the randomized distribution. The deviations from random expectation were significantly positive above 1600 m and negative below 2000 m, with the result that regional species richness peaked between 800 and 1200 m, and decreased rapidly at deeper depths. The highest species richness intervals corresponded to the number of individuals collected. Residuals from a regression of the deviations on individual numbers, however, still deviated from the randomized pattern. In this declining depth-diversity pattern, the Gulf of Mexico resembles other partially enclosed basins, such as the Norwegian Sea, known to have suffered geologically recent extinction events. This displaced diversity pattern and broad depth ranges implicate ongoing re-colonization of the deeper parts of the Gulf of Mexico. The Sigsbee Abyssal Plain sites could be depauperate for historical reasons (e.g., one or more extinction events) rather than ongoing ecological reasons (e.g., low food supply).

Development of a cloud-screening method for MAX-DOAS measurements

NASA Astrophysics Data System (ADS)

Gielen, Clio; Van Roozendael, Michel; Hendrik, Francois; Fayt, Caroline; Hermans, Christian; Pinardi, Gaia; Vlemmix, Tim

2013-04-01

In recent years, ground-based multi-axis differential absorption spectroscopy (MAX-DOAS) has shown to be ideally suited for the retrieval of tropospheric trace gases and deriving information on the aerosol properties. These measurements are invaluable to our understanding of the physics and chemistry of the atmospheric system, and the impact on the Earth's climate. Unfortunately, MAX-DOAS measurements are often performed under (partially) cloudy conditions, causing data quality degradation and higher uncertainties on the retrievals. A high aerosol load and/or a strong cloud cover can introduce additional photon absorption or multiple scattering. The first effect strongly impacts the retrieved differential slant columns (DSCDs) of the trace gases, leading to an underestimation of the atmospheric column density. Multiple scattering, on the other hand, becomes important for low clouds with a high optical depth, and cause a strong increase in the retrieved trace gas DSCDs. The presence of thin clouds can furthermore introduce a degeneracy in the retrieved aerosol optical depth, since they will have similar effect on the MAX-DOAS measurements. In this case, only information on the trace gas DSCDs can be successfully retrieved. If the cloud cover consists of broken or scattered clouds, the MAX-DOAS method becomes very unstable, since the different elevation angels will probe regions of the sky with strongly deviating properties. Here we present a method to qualify the sky and cloud conditions, using the colour index and O4 DSCDs, as derived from the MAX-DOAS measurements. The colour index is defined as the ratio of the intensities at the short- and long-wavelength part of the visible spectral range, typically at 400 nm and 670 nm. For increasing optical thickness due to clouds or aerosols, the colour index values decrease and values for different elevation angles converge. In the case of broken clouds, the colour index shows a strong and rapid temporal variation, which is easily detectable. Additional information is derived from the O4 DSCD measurements, since they are quite sensitive to the change of the light paths due to scattering at different altitudes. For example, thick clouds at low altitude show a very strong increase in the DSCD values due to scattering, combined with a low colour index value due to the intensity screening. In general, our method shows promising results to qualify the sky and cloud conditions of MAX- DOAS measurements, without the need for other external cloud-detection systems such as Brewer instruments or pyrheliometers.

The practice and clinical implications of tablet splitting in international health

PubMed Central

Elliott, Ivo; Mayxay, Mayfong; Yeuichaixong, Sengchanh; Lee, Sue J; Newton, Paul N

2014-01-01

Objective Tablet splitting is frequently performed to facilitate correct dosing, but the practice and implications in low-income settings have rarely been discussed. Methods We selected eight drugs, with narrow therapeutic indices or critical dosages, frequently divided in the Lao PDR (Laos). These were split, by common techniques used in Laos, by four nurses and four laypersons. The mean percentage deviation from the theoretical expected weight and weight loss of divided tablets/capsules were recorded. Results Five of eight study drugs failed, on splitting, to meet European Pharmacopoeia recommendations for tablet weight deviation from the expected weight of tablet/capsule halves with 10% deviating by more than 25%. There was a significant difference in splitting accuracy between nurses and laypersons (P = 0.027). Coated and unscored tablets were less accurately split than uncoated (P = 0.03 and 0.0019 for each half) and scored (0.0001 for both halves) tablets. Conclusion These findings have potential clinical implications on treatment outcome and the development of antimicrobial resistance. Investment by drug companies in a wider range of dosage units, particularly for narrow therapeutic index and critical dosage medicines, is strongly recommended. PMID:24702766

THE EFFECTS OF BODY MASS, PHYLOGENY, HABITAT, AND TROPHIC LEVEL ON MAMMALIAN AGE AT FIRST REPRODUCTION.

PubMed

Wootton, J Timothy

1987-07-01

I examined age at first reproduction of 547 mammalian species to determine the influence of diet and habitat on the evolution of life-history traits. Body mass correlated positively with age at first reproduction, explaining 56% of the variance. Habitat and trophic groups deviated significantly from the allometric curve in a pattern generally consistent with predictions from r/K selection theory and its modifications. However, mammalian orders also deviated significantly from the allometric curve, and different habitat and diet groups contained different ratios of mammalian orders. When the effects of orders were removed, residual deviations did not differ among ecological groups. Adjusting for ecological differences did not eliminate the differences between orders. These results suggest that body mass (or some correlated factor) and phylogeny strongly constrain age at first reproduction. Ecological factors appear to have little effect on the evolution of age at first reproduction. Apparent differences in weight-specific ages at first reproduction within habitats and trophic groups may be the result of ecological selection of order composition in the present, rather than ecologically driven evolution of life history in the past. © 1987 The Society for the Study of Evolution.

Gaia DR1 Evidence of Disrupting the Perseus Arm

NASA Astrophysics Data System (ADS)

Baba, Junichi; Kawata, Daisuke; Matsunaga, Noriyuki; Grand, Robert J. J.; Hunt, Jason A. S.

2018-02-01

We have discovered a clear sign of the disruption phase of the Perseus arm in the Milky Way using Cepheid variables, taking advantage of the accurately measured distances of Cepheids and the proper motions from Gaia Data Release 1. Both the Galactocentric radial and rotation velocities of 77 Cepheids within 1.5 kpc of the Perseus arm are correlated with their distances from the locus of the Perseus arm, as the trailing side is rotating faster and moving inward compared to the leading side. We also found a negative vertex deviation for the Cepheids on the trailing side, ‑27.°6 ± 2.°4, in contrast to the positive vertex deviation in the solar neighborhood. This is, to our knowledge, the first direct evidence that the vertex deviation around the Perseus arm is affected by the spiral arm. We compared these observational trends with our N-body/hydrodynamics simulations based on a static density-wave spiral scenario and with those based on a transient dynamic spiral scenario. Although our comparisons are limited to qualitative trends, they strongly favor the conclusion that the Perseus arm is in the disruption phase of a transient arm.

Evaluation of the MV (CAPON) Coherent Doppler Lidar Velocity Estimator

NASA Technical Reports Server (NTRS)

Lottman, B.; Frehlich, R.

1997-01-01

The performance of the CAPON velocity estimator for coherent Doppler lidar is determined for typical space-based and ground-based parameter regimes. Optimal input parameters for the algorithm were determined for each regime. For weak signals, performance is described by the standard deviation of the good estimates and the fraction of outliers. For strong signals, the fraction of outliers is zero. Numerical effort was also determined.

"The Errors Were the Results of Errors": Promoting Good Writing by Bad Example

ERIC Educational Resources Information Center

Korsunsky, Boris

2010-01-01

We learn best by example--this adage is probably as old as teaching itself. In my own classroom, I have found that very often the students learn best from the "negative" examples. Perhaps, this shouldn't come as a surprise at all. After all, we don't react strongly to the norm--but an obvious deviation from the norm may attract our attention and…

A randomized controlled trial investigating the effects of craniosacral therapy on pain and heart rate variability in fibromyalgia patients.

PubMed

Castro-Sánchez, Adelaida María; Matarán-Peñarrocha, Guillermo A; Sánchez-Labraca, Nuria; Quesada-Rubio, José Manuel; Granero-Molina, José; Moreno-Lorenzo, Carmen

2011-01-01

Fibromyalgia is a prevalent musculoskeletal disorder associated with widespread mechanical tenderness, fatigue, non-refreshing sleep, depressed mood and pervasive dysfunction of the autonomic nervous system: tachycardia, postural intolerance, Raynaud's phenomenon and diarrhoea. To determine the effects of craniosacral therapy on sensitive tender points and heart rate variability in patients with fibromyalgia. A randomized controlled trial. Ninety-two patients with fibromyalgia were randomly assigned to an intervention group or placebo group. Patients received treatments for 20 weeks. The intervention group underwent a craniosacral therapy protocol and the placebo group received sham treatment with disconnected magnetotherapy equipment. Pain intensity levels were determined by evaluating tender points, and heart rate variability was recorded by 24-hour Holter monitoring. After 20 weeks of treatment, the intervention group showed significant reduction in pain at 13 of the 18 tender points (P < 0.05). Significant differences in temporal standard deviation of RR segments, root mean square deviation of temporal standard deviation of RR segments and clinical global impression of improvement versus baseline values were observed in the intervention group but not in the placebo group. At two months and one year post therapy, the intervention group showed significant differences versus baseline in tender points at left occiput, left-side lower cervical, left epicondyle and left greater trochanter and significant differences in temporal standard deviation of RR segments, root mean square deviation of temporal standard deviation of RR segments and clinical global impression of improvement. Craniosacral therapy improved medium-term pain symptoms in patients with fibromyalgia.

Deviation of paleomagnetic directions on basaltic lava flows determined by rock magnetic fabrics

NASA Astrophysics Data System (ADS)

Silva, Pedro; Henry, Bernard; Gallet, Yves; Martins, Sofia; Lopes, Ana; Moreira, Mário; Genevey, Agnès; Mata, João; Nunes, João; Neres, Marta; Meriaux, Anne-Sophie; Madeira, José

2016-04-01

Some paleomagnetic works conducted in lava flows retrieve characteristic remanent directions that shows an inclination shallowing relatively to the expected Geocentric Axial Dipole. Contributions of non-dipole components to the resultant Earth magnetic field and/or deficient time covering of the paleosecular variation are the most pointed causes for such shallowing. Another, but often overlooked source of shallowing, is the magnetic anisotropy carried by lava flows. In order to bring more insights about this research topic, four historical basaltic lava flows (corresponding to nine sampled sites) from Azores (Terceira and Pico islands) were studied. Detailed paleomagnetic and magnetic fabric analyses (anisotropy of magnetic susceptibility AMS and of anhysteretic remanence AARM) were complemented by petrographic observations of oriented thin sections. Our study shows that the majority of the analysed sites display a low degree of anisotropy (corrected degrees of anisotropy, Pj, lower than 1.03), sometimes accompanied by exchanges between principal axes of the magnetic susceptibility ellipsoid. For such cases the corresponding paleomagnetic directions are well grouped with a Fisher distribution. The sites, where Pj is higher than 1.03 (reaching 1.15), present a triaxial magnetic susceptibility ellipsoid and the paleomagnetic directions show a lengthened distribution. Spatial distribution of AMS and AARM ellipsoids axes are very similar. Petrographic observations show flow structures that agree with AMS and AARM ellipsoid. Comparing AMS and main paleomagnetic directions retrieved for lava flows with the highest anisotropy, 20° variation in inclination of paleomagnetic directions is observed. This inclination varies almost linearly with the degree of anisotropy through an inverse correlation. A shift of paleomagnetic declinations is also observed, which agrees with changes in the direction of the maximum principal axes of AMS ellipsoid. These results clearly show that paleomagnetic directions on basaltic rocks can be strongly deviated from the field direction. Accordingly, preliminary analyses of rock fabrics (magnetic and microstructural) are fundamental for such kind of paleomagnetic works. The author wish to acknowledge REGENA project (PTDC/GEO-FIQ/3648/2012) for its major contribution without which this work wouldn't be possible. Publication supported by project FCT UID/GEO/50019/2013 - Instituto Dom Luiz.

Testing the equivalence principle on cosmological scales

NASA Astrophysics Data System (ADS)

Bonvin, Camille; Fleury, Pierre

2018-05-01

The equivalence principle, that is one of the main pillars of general relativity, is very well tested in the Solar system; however, its validity is more uncertain on cosmological scales, or when dark matter is concerned. This article shows that relativistic effects in the large-scale structure can be used to directly test whether dark matter satisfies Euler's equation, i.e. whether its free fall is characterised by geodesic motion, just like baryons and light. After having proposed a general parametrisation for deviations from Euler's equation, we perform Fisher-matrix forecasts for future surveys like DESI and the SKA, and show that such deviations can be constrained with a precision of order 10%. Deviations from Euler's equation cannot be tested directly with standard methods like redshift-space distortions and gravitational lensing, since these observables are not sensitive to the time component of the metric. Our analysis shows therefore that relativistic effects bring new and complementary constraints to alternative theories of gravity.

Prediction limits of mobile phone activity modelling

NASA Astrophysics Data System (ADS)

Kondor, Dániel; Grauwin, Sebastian; Kallus, Zsófia; Gódor, István; Sobolevsky, Stanislav; Ratti, Carlo

2017-02-01

Thanks to their widespread usage, mobile devices have become one of the main sensors of human behaviour and digital traces left behind can be used as a proxy to study urban environments. Exploring the nature of the spatio-temporal patterns of mobile phone activity could thus be a crucial step towards understanding the full spectrum of human activities. Using 10 months of mobile phone records from Greater London resolved in both space and time, we investigate the regularity of human telecommunication activity on urban scales. We evaluate several options for decomposing activity timelines into typical and residual patterns, accounting for the strong periodic and seasonal components. We carry out our analysis on various spatial scales, showing that regularity increases as we look at aggregated activity in larger spatial units with more activity in them. We examine the statistical properties of the residuals and show that it can be explained by noise and specific outliers. Also, we look at sources of deviations from the general trends, which we find to be explainable based on knowledge of the city structure and places of attractions. We show examples how some of the outliers can be related to external factors such as specific social events.

Mid-Pliocene equatorial Pacific sea surface temperature reconstruction: a multi-proxy perspective

USGS Publications Warehouse

Dowsett, Harry J.; Robinson, Marci M.

2009-01-01

The Mid-Pliocene is the most recent interval of sustained global warmth, which can be used to examine conditions predicted for the near future. An accurate spatial representation of the low-latitude Mid-Pliocene Pacific surface ocean is necessary to understand past climate change in the light of forecasts of future change. Mid-Pliocene sea surface temperature (SST) anomalies show a strong contrast between the western equatorial Pacific (WEP) and eastern equatorial Pacific (EEP) regardless of proxy (faunal, alkenone and Mg/Ca). All WEP sites show small differences from modern mean annual temperature, but all EEP sites show significant positive deviation from present-day temperatures by as much as 4.4°C. Our reconstruction reflects SSTs similar to modern in the WEP, warmer than modern in the EEP and eastward extension of the WEP warm pool. The east-west equatorial Pacific SST gradient is decreased, but the pole to equator gradient does not change appreciably. We find it improbable that increased greenhouse gases (GHG) alone would cause such a heterogeneous warming and more likely that the cause of Mid-Pliocene warmth is a combination of several forcings including both increased meridional heat transport and increased GHG.

Mid-Pliocene equatorial Pacific sea surface temperature reconstruction: A multi-proxy perspective

USGS Publications Warehouse

Dowsett, H.J.; Robinson, M.M.

2009-01-01

The Mid-Pliocene is the most recent interval of sustained global warmth, which can be used to examine conditions predicted for the near future. An accurate spatial representation of the low-latitude Mid-Pliocene Pacific surface ocean is necessary to understand past climate change in the light of forecasts of future change. Mid-Pliocene sea surface temperature (SST) anomalies show a strong contrast between the western equatorial Pacific (WEP) and eastern equatorial Pacific (EEP) regardless of proxy (faunal, alkenone and Mg/Ca). All WEP sites show small differences from modern mean annual temperature, but all EEP sites show significant positive deviation from present-day temperatures by as much as 4.4??C. Our reconstruction reflects SSTs similar to modern in the WEP, warmer than modern in the EEP and eastward extension of the WEP warm pool. The east-west equatorial Pacific SST gradient is decreased, but the pole to equator gradient does not change appreciably. We find it improbable that increased greenhouse gases (GHG) alone would cause such a heterogeneous warming and more likely that the cause of Mid-Pliocene warmth is a combination of several forcings including both increased meridional heat transport and increased GHG. ?? 2008 The Royal Society.

Prediction limits of mobile phone activity modelling.

PubMed

Kondor, Dániel; Grauwin, Sebastian; Kallus, Zsófia; Gódor, István; Sobolevsky, Stanislav; Ratti, Carlo

2017-02-01

Thanks to their widespread usage, mobile devices have become one of the main sensors of human behaviour and digital traces left behind can be used as a proxy to study urban environments. Exploring the nature of the spatio-temporal patterns of mobile phone activity could thus be a crucial step towards understanding the full spectrum of human activities. Using 10 months of mobile phone records from Greater London resolved in both space and time, we investigate the regularity of human telecommunication activity on urban scales. We evaluate several options for decomposing activity timelines into typical and residual patterns, accounting for the strong periodic and seasonal components. We carry out our analysis on various spatial scales, showing that regularity increases as we look at aggregated activity in larger spatial units with more activity in them. We examine the statistical properties of the residuals and show that it can be explained by noise and specific outliers. Also, we look at sources of deviations from the general trends, which we find to be explainable based on knowledge of the city structure and places of attractions. We show examples how some of the outliers can be related to external factors such as specific social events.

Regulatory cells induced by acute toxoplasmosis prevent the development of allergic lung inflammation.

PubMed

Fenoy, Ignacio M; Sanchez, Vanesa R; Soto, Ariadna S; Picchio, Mariano S; Maglioco, Andrea; Corigliano, Mariana G; Dran, Graciela I; Martin, Valentina; Goldman, Alejandra

2015-05-01

The increased prevalence of allergies in developed countries has been attributed to a reduction of some infections. Supporting epidemiological studies, we previously showed that both acute and chronic Toxoplasma gondii infection can diminish allergic airway inflammation in BALB/c mice. The mechanisms involved when sensitization occurs during acute phase would be related to the strong Th1 response induced by the parasite. Here, we further investigated the mechanisms involved in T. gondii allergy protection in mice sensitized during acute T. gondii infection. Adoptive transference assays and ex vivo co-cultures experiments showed that not only thoracic lymph node cells from infected and sensitized mice but also from non-sensitized infected animals diminished both allergic lung inflammation and the proliferation of effector T cells from allergic mice. This ability was found to be contact-independent and correlated with high levels of CD4(+)FoxP3(+) cells. IL-10 would not be involved in allergy suppression since IL-10-deficient mice behaved similar to wild type mice. Our results extend earlier work and show that, in addition to immune deviation, acute T. gondii infection can suppress allergic airway inflammation through immune suppression. Copyright © 2014 Elsevier GmbH. All rights reserved.

EFFECTIVE INDICES FOR MONITORING MENTAL WORKLOAD WHILE PERFORMING MULTIPLE TASKS.

PubMed

Hsu, Bin-Wei; Wang, Mao-Jiun J; Chen, Chi-Yuan; Chen, Fang

2015-08-01

This study identified several physiological indices that can accurately monitor mental workload while participants performed multiple tasks with the strategy of maintaining stable performance and maximizing accuracy. Thirty male participants completed three 10-min. simulated multitasks: MATB (Multi-Attribute Task Battery) with three workload levels. Twenty-five commonly used mental workload measures were collected, including heart rate, 12 HRV (heart rate variability), 10 EEG (electroencephalography) indices (α, β, θ, α/θ, θ/β from O1-O2 and F4-C4), and two subjective measures. Analyses of index sensitivity showed that two EEG indices, θ and α/θ (F4-C4), one time-domain HRV-SDNN (standard deviation of inter-beat intervals), and four frequency-domain HRV: VLF (very low frequency), LF (low frequency), %HF (percentage of high frequency), and LF/HF were sensitive to differentiate high workload. EEG α/θ (F4-C4) and LF/HF were most effective for monitoring high mental workload. LF/HF showed the highest correlations with other physiological indices. EEG α/θ (F4-C4) showed strong correlations with subjective measures across different mental workload levels. Operation strategy would affect the sensitivity of EEG α (F4-C4) and HF.

Mid-Pliocene equatorial Pacific sea surface temperature reconstruction: a multi-proxy perspective.

PubMed

Dowsett, Harry J; Robinson, Marci M

2009-01-13

The Mid-Pliocene is the most recent interval of sustained global warmth, which can be used to examine conditions predicted for the near future. An accurate spatial representation of the low-latitude Mid-Pliocene Pacific surface ocean is necessary to understand past climate change in the light of forecasts of future change. Mid-Pliocene sea surface temperature (SST) anomalies show a strong contrast between the western equatorial Pacific (WEP) and eastern equatorial Pacific (EEP) regardless of proxy (faunal, alkenone and Mg/Ca). All WEP sites show small differences from modern mean annual temperature, but all EEP sites show significant positive deviation from present-day temperatures by as much as 4.4 degrees C. Our reconstruction reflects SSTs similar to modern in the WEP, warmer than modern in the EEP and eastward extension of the WEP warm pool. The east-west equatorial Pacific SST gradient is decreased, but the pole to equator gradient does not change appreciably. We find it improbable that increased greenhouse gases (GHG) alone would cause such a heterogeneous warming and more likely that the cause of Mid-Pliocene warmth is a combination of several forcings including both increased meridional heat transport and increased GHG.

Validation of Cut-Points for Evaluating the Intensity of Physical Activity with Accelerometry-Based Mean Amplitude Deviation (MAD).

PubMed

Vähä-Ypyä, Henri; Vasankari, Tommi; Husu, Pauliina; Mänttäri, Ari; Vuorimaa, Timo; Suni, Jaana; Sievänen, Harri

2015-01-01

Our recent study of three accelerometer brands in various ambulatory activities showed that the mean amplitude deviation (MAD) of the resultant acceleration signal performed best in separating different intensity levels and provided excellent agreement between the three devices. The objective of this study was to derive a regression model that estimates oxygen consumption (VO2) from MAD values and validate the MAD-based cut-points for light, moderate and vigorous locomotion against VO2 within a wide range of speeds. 29 participants performed a pace-conducted non-stop test on a 200 m long indoor track. The initial speed was 0.6 m/s and it was increased by 0.4 m/s every 2.5 minutes until volitional exhaustion. The participants could freely decide whether they preferred to walk or run. During the test they carried a hip-mounted tri-axial accelerometer and mobile metabolic analyzer. The MAD was calculated from the raw acceleration data and compared to directly measured incident VO2. Cut-point between light and moderate activity was set to 3.0 metabolic equivalent (MET, 1 MET = 3.5 ml · kg-1 · min-1) and between moderate and vigorous activity to 6.0 MET as per standard use. The MAD and VO2 showed a very strong association. Within individuals, the range of r values was from 0.927 to 0.991 providing the mean r = 0.969. The optimal MAD cut-point for 3.0 MET was 91 mg (milligravity) and 414 mg for 6.0 MET. The present study showed that the MAD is a valid method in terms of the VO2 within a wide range of ambulatory activities from slow walking to fast running. Being a device-independent trait, the MAD facilitates directly comparable, accurate results on the intensity of physical activity with all accelerometers providing tri-axial raw data.

Critical re-appraisal of blood component quality after overnight hold of whole blood outside current room temperature limits.

PubMed

Bontekoe, I J; van der Meer, P F; de Korte, D

2017-02-01

According to European guidelines, the temperature of whole blood (WB) has to be maintained at 20-24°C until processing within 24 h, but in blood bank practice, WB is frequently held at temperatures between 18-25°C. We aimed to assess the impact of these small temperature deviations on the quality of the blood components. After rapid cooling, 7 WB units were held overnight at 18°C and 8 units at 25°C, reflecting worst case holding conditions, and separated into a red cell concentrate (RCC), plasma and buffy coat (BC). RCCs were filtered at test temperature and stored for 42 days at 2-6°C. BCs were processed to single-BC platelet concentrates (sPC) and stored up to Day 8 at 20-24°C. After overnight hold at 18°C, 2,3-DPG in WB decreased by 34 ± 9%, while at 25°C the decrease was 82 ± 6%. Accordingly, the 2,3-DPG levels in the RCCs in the 25°C group were significantly lower than in the 18°C group (2·2 ± 1·4 vs. 10·4 ± 2·9 μmol/g Hb). RCCs and sPCs in the 25°C group showed higher initial lactate levels and lower pH compared to the 18°C group, but these differences levelled off at the end of storage. RCCs showed small differences in ATP levels and haemolysis. Plasma in both groups showed comparable Factor VIII:C levels. The temperature of WB during overnight hold strongly affects initial 2,3-DPG levels of RCCs and supports the maintenance of temperature limits between 20 and 24°C. Other in vitro effects of the temperature deviations were small and of no practical relevance. © 2016 International Society of Blood Transfusion.

Neoclassical canons of facial beauty: Do we see the deviations?

PubMed

Pavlic, Andrej; Trinajstic Zrinski, Magda; Katic, Visnja; Spalj, Stjepan

2017-05-01

To explore the presence of neoclassical canons of facial beauty among young people in Croatia and to question possible psychosocial repercussions occurring in those who demonstrate deviations in relation to canons. The study was cross-sectional and the sample included 249 subjects (60% female) aged 12-39 (median 20). Their en face and profile photographs were taken in Natural Head Position. Photogrammetry included analysis of nine neoclassical canons of facial beauty originating from the Renaissance. Psychosocial issues were assessed using the Self-Esteem Scale, Big Five Inventory and three domains of Orthognathic Quality of Life Questionnaire. Significant deviations from neoclassical facial beauty canons were observed in 55-65% of adolescents and young adults. Gender and age showed no relation to deviations. The deviations from canons that influenced the quality of life were mainly those related to vertical facial proportions and demonstrated increased facial aesthetics concern and social impact, and higher self-reported treatment need (p < 0.05). Deviations from canons were not related to self-esteem but a decrease in openness, agreeableness and neuroticism was observed. Neoclassical canons were not valid for the majority of adolescents and young adults in Croatia. Only deviations from some canons appear to provoke mild psychosocial repercussions. Copyright © 2017 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Distractor Evoked Deviations of Saccade Trajectory Are Modulated by Fixation Activity in the Superior Colliculus: Computational and Behavioral Evidence

PubMed Central

Wang, Zhiguo; Theeuwes, Jan

2014-01-01

Previous studies have shown that saccades may deviate towards or away from task irrelevant visual distractors. This observation has been attributed to active suppression (inhibition) of the distractor location unfolding over time: early in time inhibition at the distractor location is incomplete causing deviation towards the distractor, while later in time when inhibition is complete the eyes deviate away from the distractor. In a recent computational study, Wang, Kruijne and Theeuwes proposed an alternative theory that the lateral interactions in the superior colliculus (SC), which are characterized by short-distance excitation and long-distance inhibition, are sufficient for generating both deviations towards and away from distractors. In the present study, we performed a meta-analysis of the literature, ran model simulations and conducted two behavioral experiments to further explore this unconventional theory. Confirming predictions generated by the model simulations, the behavioral experiments show that a) saccades deviate towards close distractors and away from remote distractors, and b) the amount of deviation depends on the strength of fixation activity in the SC, which can be manipulated by turning off the fixation stimulus before or after target onset (Experiment 1), or by varying the eccentricity of the target and distractor (Experiment 2). PMID:25551552

Changes in Income at Macro Level Predict Sex Ratio at Birth in OECD Countries.

PubMed

Kanninen, Ohto; Karhula, Aleksi

2016-01-01

The human sex ratio at birth (SRB) is approximately 107 boys for every 100 girls. SRB was rising until the World War II and has been declining slightly after the 1950s in several industrial countries. Recent studies have shown that SRB varies according to exposure to disasters and socioeconomic conditions. However, it remains unknown whether changes in SRB can be explained by observable macro-level socioeconomic variables across multiple years and countries. Here we show that changes in disposable income at the macro level positively predict SRB in OECD countries. A one standard deviation increase in the change of disposable income is associated with an increase of 1.03 male births per 1000 female births. The relationship is possibly nonlinear and driven by extreme changes. The association varies from country to country being particular strong in Estonia. This is the first evidence to show that economic and social conditions are connected to SRB across countries at the macro level. This calls for further research on the effects of societal conditions on general characteristics at birth.

Temperature-dependent magnetic anisotropy in the layered magnetic semiconductors Cr I3 and CrB r3

NASA Astrophysics Data System (ADS)

Richter, Nils; Weber, Daniel; Martin, Franziska; Singh, Nirpendra; Schwingenschlögl, Udo; Lotsch, Bettina V.; Kläui, Mathias

2018-02-01

Chromium trihalides are layered and exfoliable semiconductors and exhibit unusual magnetic properties with a surprising temperature dependence of the magnetization. By analyzing the evolution of the magnetocrystalline anisotropy with temperature in chromium iodide Cr I3 , we find it strongly changes from Ku=300 ±50 kJ / m3 at 5 K to Ku=43 ±7 kJ / m3 at 60 K , close to the Curie temperature. We draw a direct comparison to CrB r3 , which serves as a reference, and where we find results consistent with literature. In particular, we show that the anisotropy change in the iodide compound is more than 3 times larger than in the bromide. We analyze this temperature dependence using a classical model, showing that the anisotropy constant scales with the magnetization at any given temperature below the Curie temperature, indicating that the temperature dependence can be explained by a dominant uniaxial anisotropy where this scaling results from local spin clusters having thermally induced magnetization directions that deviate from the overall magnetization.

Concurrent validation of CHIRP, a new instrument for measuring healthcare student attitudes towards interdisciplinary teamwork.

PubMed

Hollar, David; Hobgood, Cherri; Foster, Beverly; Aleman, Marco; Sawning, Susan

2012-01-01

Positive attitudes towards teamwork among health care professionals are critical to patient safety. The purpose of this study is to describe the development and concurrent validation of a new instrument to measure attitudes towards healthcare teamwork that is generalizable across various populations of healthcare students. The Collaborative Healthcare Interdisciplinary Planning (CHIRP) scale was validated against the Readiness for Inter-Professional Learning Scale (RIPLS). Analyses included student (n = 266) demographics, ANOVA, internal consistency, factor analysis, and Rasch analysis. The two instruments correlated at r = .582. The CHIRP showed a multifactorial structure having excellent internal consistency (alpha = .850), with 25 of the 36 scale items loading onto a single Teamwork Attitudes factor. The RIPLS likewise had strong internal consistency (alpha = .796) and a three-factor structure, supporting previous studies of the instrument. However, Rasch analyses showed 14 (38.9%) of the 36 CHIRP items, but only four (21.1%) of the 19 RIPLS items remaining within the satisfactory standardized OUTFIT zone of 2.0 standard deviation units. We propose the 14 fitting items as a new, validated teamwork attitudes scale.

Buckling in armored droplets.

PubMed

Sicard, François; Striolo, Alberto

2017-06-29

The buckling mechanism in droplets stabilized by solid particles (armored droplets) is tackled at a mesoscopic level using dissipative particle dynamics simulations. We consider one spherical water droplet in a decane solvent coated with nanoparticle monolayers of two different types: Janus (particles whose surface shows two regions with different wetting properties) and homogeneous. The chosen particles yield comparable initial three-phase contact angles, selected to maximize the adsorption energy at the interface. We study the interplay between the evolution of droplet shape, layering of the particles, and their distribution at the interface when the volume of the droplets is reduced. We show that Janus particles affect strongly the shape of the droplet with the formation of a crater-like depression. This evolution is actively controlled by a close-packed particle monolayer at the curved interface. In contrast, homogeneous particles follow passively the volume reduction of the droplet, whose shape does not deviate too much from spherical, even when a nanoparticle monolayer/bilayer transition is detected at the interface. We discuss how these buckled armored droplets might be of relevance in various applications including potential drug delivery systems and biomimetic design of functional surfaces.

Nanoscale simple-fluid behavior under steady shear.

PubMed

Yong, Xin; Zhang, Lucy T

2012-05-01

In this study, we use two nonequilibrium molecular dynamics algorithms, boundary-driven shear and homogeneous shear, to explore the rheology and flow properties of a simple fluid undergoing steady simple shear. The two distinct algorithms are designed to elucidate the influences of nanoscale confinement. The results of rheological material functions, i.e., viscosity and normal pressure differences, show consistent Newtonian behaviors at low shear rates from both systems. The comparison validates that confinements of the order of 10 nm are not strong enough to deviate the simple fluid behaviors from the continuum hydrodynamics. The non-Newtonian phenomena of the simple fluid are further investigated by the homogeneous shear simulations with much higher shear rates. We observe the "string phase" at high shear rates by applying both profile-biased and profile-unbiased thermostats. Contrary to other findings where the string phase is found to be an artifact of the thermostats, we perform a thorough analysis of the fluid microstructures formed due to shear, which shows that it is possible to have a string phase and second shear thinning for dense simple fluids.

Study on the flow nonuniformity in a high capacity Stirling pulse tube cryocooler

NASA Astrophysics Data System (ADS)

You, X.; Zhi, X.; Duan, C.; Jiang, X.; Qiu, L.; Li, J.

2017-12-01

High capacity Stirling-type pulse tube cryocoolers (SPTC) have promising applications in high temperature superconductive motor and gas liquefaction. However, with the increase of cooling capacity, its performance deviates from well-accepted one-dimensional model simulation, such as Sage and Regen, mainly due to the strong field nonuniformity. In this study, several flow straighteners placed at both ends of the pulse tube are investigated to improve the flow distribution. A two-dimensional model of the pulse tube based on the computational fluid dynamics (CFD) method has been built to study the flow distribution of the pulse tube with different flow straighteners including copper screens, copper slots, taper transition and taper stainless slot. A SPTC set-up which has more than one hundred Watts cooling power at 80 K has been built and tested. The flow straighteners mentioned above have been applied and tested. The results show that with the best flow straightener the cooling performance of the SPTC can be significantly improved. Both CFD simulation and experiment show that the straighteners have impacts on the flow distribution and the performance of the high capacity SPTC.

Some statistical investigations on the nature and dynamics of electricity prices

NASA Astrophysics Data System (ADS)

Bottazzi, G.; Sapio, S.; Secchi, A.

2005-09-01

This work analyzes the log-returns of daily electricity prices from the NordPool day-ahead market. We study both the unconditional growth rates distribution and the distribution of residual shocks obtained with a non-parametric filtering procedure based on the Cholesky factor algorithm. We show that, even if the Subbotin family of distributions is able to describe the empirical observations in both cases, the Subbotin fit obtained for the unconditional growth rates and for the residual shocks reveal significant differences. Indeed, the sequence of log-returns can be described as the outcome of an aggregation of Laplace-distributed shocks with time-dependent volatility. We find that the standard deviation of shocks scales as a power law of the initial price level, with scaling exponent around -1. Moreover, the analysis of the empirical density of shocks, conditional on the price level, shows a strong relationship of the Subbotin fit with the latter. We conclude that the unconditional growth rates distribution is the superposition of shocks distributions characterized by decreasing volatility and fat-tailedness with respect to the price level.

Chemodynamical modelling of the galactic bulge and bar

NASA Astrophysics Data System (ADS)

Portail, Matthieu; Wegg, Christopher; Gerhard, Ortwin; Ness, Melissa

2017-09-01

We present the first self-consistent chemodynamical model fitted to reproduce data for the galactic bulge, bar and inner disc. We extend the Made-to-Measure method to an augmented phase-space including the metallicity of stars, and show its first application to the bar region of the Milky Way. Using data from the ARGOS and APOGEE (DR12) surveys, we adapt the recent dynamical model from Portail et al. to reproduce the observed spatial and kinematic variations as a function of metallicity, thus allowing the detailed study of the 3D density distributions, kinematics and orbital structure of stars in different metallicity bins. We find that metal-rich stars with [Fe/H] ≥ -0.5 are strongly barred and have dynamical properties that are consistent with a common disc origin. Metal-poor stars with [Fe/H] ≤ -0.5 show strong kinematic variations with metallicity, indicating varying contributions from the underlying stellar populations. Outside the central kpc, metal-poor stars are found to have the density and kinematics of a thick disc while in the inner kpc, evidence for an extra concentration of metal-poor stars is found. Finally, the combined orbit distributions of all metallicities in the model naturally reproduce the observed vertex deviations in the bulge. This paper demonstrates the power of Made-to-Measure chemodynamical models, that when extended to other chemical dimensions will be very powerful tools to maximize the information obtained from large spectroscopic surveys such as APOGEE, GALAH and MOONS.

Research on frequency control strategy of interconnected region based on fuzzy PID

NASA Astrophysics Data System (ADS)

Zhang, Yan; Li, Chunlan

2018-05-01

In order to improve the frequency control performance of the interconnected power grid, overcome the problems of poor robustness and slow adjustment of traditional regulation, the paper puts forward a frequency control method based on fuzzy PID. The method takes the frequency deviation and tie-line deviation of each area as the control objective, takes the regional frequency deviation and its deviation as input, and uses fuzzy mathematics theory, adjusts PID control parameters online. By establishing the regional frequency control model of water-fire complementary power generation in MATLAB, the regional frequency control strategy is given, and three control modes (TBC-FTC, FTC-FTC, FFC-FTC) are simulated and analyzed. The simulation and experimental results show that, this method has better control performance compared with the traditional regional frequency regulation.

Scaling Deviations for Neutrino Reactions in Aysmptotically Free Field Theories

DOE R&D Accomplishments Database

Wilczek, F. A.; Zee, A.; Treiman, S. B.

1974-11-01

Several aspects of deep inelastic neutrino scattering are discussed in the framework of asymptotically free field theories. We first consider the growth behavior of the total cross sections at large energies. Because of the deviations from strict scaling which are characteristic of such theories the growth need not be linear. However, upper and lower bounds are established which rather closely bracket a linear growth. We next consider in more detail the expected pattern of scaling deviation for the structure functions and, correspondingly, for the differential cross sections. The analysis here is based on certain speculative assumptions. The focus is on qualitative effects of scaling breakdown as they may show up in the X and y distributions. The last section of the paper deals with deviations from the Callan-Gross relation.

Stability in a fiber bundle model: Existence of strong links and the effect of disorder

NASA Astrophysics Data System (ADS)

Roy, Subhadeep

2018-05-01

The present paper deals with a fiber bundle model which consists of a fraction α of infinitely strong fibers. The inclusion of such an unbreakable fraction has been proven to affect the failure process in early studies, especially around a critical value αc. The present work has a twofold purpose: (i) a study of failure abruptness, mainly the brittle to quasibrittle transition point with varying α and (ii) variation of αc as we change the strength of disorder introduced in the model. The brittle to quasibrittle transition is confirmed from the failure abruptness. On the other hand, the αc is obtained from the knowledge of failure abruptness as well as the statistics of avalanches. It is observed that the brittle to quasibrittle transition point scales to lower values, suggesting more quasi-brittle-like continuous failure when α is increased. At the same time, the bundle becomes stronger as there are larger numbers of strong links to support the external stress. High α in a highly disordered bundle leads to an ideal situation where the bundle strength, as well as the predictability in failure process is very high. Also, the critical fraction αc, required to make the model deviate from the conventional results, increases with decreasing strength of disorder. The analytical expression for αc shows good agreement with the numerical results. Finally, the findings in the paper are compared with previous results and real-life applications of composite materials.

Relationships between teleconnection patterns and Turkish climatic extremes

NASA Astrophysics Data System (ADS)

Baltacı, H.; Akkoyunlu, B. O.; Tayanç, M.

2017-12-01

This is a study on the effects of teleconnection patterns (TPs) on the extremes of temperature and precipitation over Turkey. Relationships between five teleconnection patterns, North Atlantic Oscillation (NAO), Arctic Oscillation (AO), East Atlantic-Western Russia (EAWR), East Atlantic (EA), and Scandinavian (SCA) patterns, and 11 climate extreme indices were studied by using 94 uniformly distributed meteorological stations over Turkey for the period of 1965-2014. Analyzing strong positive and negative temperature deviations from the 50-year-winter means shows that such extremes can often be explained by using AO and EAWR patterns. During the negative AO, generally more warm days occur over Black Sea (r = -0.6) and Aegean regions (r = -0.7). This phase of AO also generates above-normal precipitation in the western parts of the Anatolian Peninsula (r around - 0.5). Winter-time negative AO is mainly associated with the presence of a deepened Genoa cyclone over Italy that can transport warm and moist air mass from Mediterranean Sea towards Turkey by strong westerly winds. In contrast, positive EAWR is mainly connected to cold nights over Black Sea (r = 0.6) and Aegean regions (r = 0.6) together with positive precipitation anomalies at the seaside stations of the eastern Black Sea region. On the other hand, when positive EAWR prevails, Azores high-pressure center expands towards continental Europe bringing cold air by strong northerly winds together with higher moisture transport from the Black Sea. These results could pave the way for new possibilities regarding the projection of extremes in downscaling techniques.

Selection of vegetation indices for mapping the sugarcane condition around the oil and gas field of North West Java Basin, Indonesia

NASA Astrophysics Data System (ADS)

Muji Susantoro, Tri; Wikantika, Ketut; Saepuloh, Asep; Handoyo Harsolumakso, Agus

2018-05-01

Selection of vegetation indices in plant mapping is needed to provide the best information of plant conditions. The methods used in this research are the standard deviation and the linear regression. This research tried to determine the vegetation indices used for mapping the sugarcane conditions around oil and gas fields. The data used in this study is Landsat 8 OLI/TIRS. The standard deviation analysis on the 23 vegetation indices with 27 samples has resulted in the six highest standard deviations of vegetation indices, termed as GRVI, SR, NLI, SIPI, GEMI and LAI. The standard deviation values are 0.47; 0.43; 0.30; 0.17; 0.16 and 0.13. Regression correlation analysis on the 23 vegetation indices with 280 samples has resulted in the six vegetation indices, termed as NDVI, ENDVI, GDVI, VARI, LAI and SIPI. This was performed based on regression correlation with the lowest value R2 than 0,8. The combined analysis of the standard deviation and the regression correlation has obtained the five vegetation indices, termed as NDVI, ENDVI, GDVI, LAI and SIPI. The results of the analysis of both methods show that a combination of two methods needs to be done to produce a good analysis of sugarcane conditions. It has been clarified through field surveys and showed good results for the prediction of microseepages.

Suppression of Self-Induced Flavor Conversion in the Supernova Accretion Phase

NASA Astrophysics Data System (ADS)

Sarikas, Srdjan; Raffelt, Georg G.; Hüdepohl, Lorenz; Janka, Hans-Thomas

2012-02-01

Self-induced flavor conversions of supernova (SN) neutrinos can strongly modify the flavor-dependent fluxes. We perform a linearized flavor stability analysis with accretion-phase matter profiles of a 15M⊙ spherically symmetric model and corresponding neutrino fluxes. We use realistic energy and angle distributions, the latter deviating strongly from quasi-isotropic emission, thus accounting for both multiangle and multienergy effects. For our matter and neutrino density profile we always find stable conditions: flavor conversions are limited to the usual Mikheyev-Smirnov-Wolfenstein effect. In this case one may distinguish the neutrino mass hierarchy in a SN neutrino signal if the mixing angle θ13 is as large as suggested by recent experiments.

Suppression of self-induced flavor conversion in the supernova accretion phase.

PubMed

Sarikas, Srdjan; Raffelt, Georg G; Hüdepohl, Lorenz; Janka, Hans-Thomas

2012-02-10

Self-induced flavor conversions of supernova (SN) neutrinos can strongly modify the flavor-dependent fluxes. We perform a linearized flavor stability analysis with accretion-phase matter profiles of a 15M[symbol: see text] spherically symmetric model and corresponding neutrino fluxes. We use realistic energy and angle distributions, the latter deviating strongly from quasi-isotropic emission, thus accounting for both multiangle and multienergy effects. For our matter and neutrino density profile we always find stable conditions: flavor conversions are limited to the usual Mikheyev-Smirnov-Wolfenstein effect. In this case one may distinguish the neutrino mass hierarchy in a SN neutrino signal if the mixing angle θ13 is as large as suggested by recent experiments.

Perception of midline deviations in smile esthetics by laypersons

PubMed Central

Ferreira, Jamille Barros; da Silva, Licínio Esmeraldo; Caetano, Márcia Tereza de Oliveira; da Motta, Andrea Fonseca Jardim; Cury-Saramago, Adriana de Alcantara; Mucha, José Nelson

2016-01-01

ABSTRACT Objective: To evaluate the esthetic perception of upper dental midline deviation by laypersons and if adjacent structures influence their judgment. Methods: An album with 12 randomly distributed frontal view photographs of the smile of a woman with the midline digitally deviated was evaluated by 95 laypersons. The frontal view smiling photograph was modified to create from 1 mm to 5 mm deviations in the upper midline to the left side. The photographs were cropped in two different manners and divided into two groups of six photographs each: group LCN included the lips, chin, and two-thirds of the nose, and group L included the lips only. The laypersons performed the rate of each smile using a visual analog scale (VAS). Wilcoxon test, Student’s t-test and Mann-Whitney test were applied, adopting a 5% level of significance. Results: Laypersons were able to perceive midline deviations starting at 1 mm. Statistically significant results (p< 0.05) were found for all multiple comparisons of the values in photographs of group LCN and for almost all comparisons in photographs of group L. Comparisons between the photographs of groups LCN and L showed statistically significant values (p< 0.05) when the deviation was 1 mm. Conclusions: Laypersons were able to perceive the upper dental midline deviations of 1 mm, and above when the adjacent structures of the smiles were included. Deviations of 2 mm and above when the lips only were included. The visualization of structures adjacent to the smile demonstrated influence on the perception of midline deviation. PMID:28125140

Influence of asymmetrical drawing radius deviation in micro deep drawing

NASA Astrophysics Data System (ADS)

Heinrich, L.; Kobayashi, H.; Shimizu, T.; Yang, M.; Vollertsen, F.

2017-09-01

Nowadays, an increasing demand for small metal parts in electronic and automotive industries can be observed. Deep drawing is a well-suited technology for the production of such parts due to its excellent qualities for mass production. However, the downscaling of the forming process leads to new challenges in tooling and process design, such as high relative deviation of tool geometry or blank displacement compared to the macro scale. FEM simulation has been a widely-used tool to investigate the influence of symmetrical process deviations as for instance a global variance of the drawing radius. This study shows a different approach that allows to determine the impact of asymmetrical process deviations on micro deep drawing. In this particular case the impact of an asymmetrical drawing radius deviation and blank displacement on cup geometry deviation was investigated for different drawing ratios by experiments and FEM simulation. It was found that both variations result in an increasing cup height deviation. Nevertheless, with increasing drawing ratio a constant drawing radius deviation has an increasing impact, while blank displacement results in a decreasing offset of the cups geometry. This is explained by different mechanisms that result in an uneven cup geometry. While blank displacement leads to material surplus on one side of the cup, an unsymmetrical radius deviation on the other hand generates uneven stretching of the cups wall. This is intensified for higher drawing ratios. It can be concluded that the effect of uneven radius geometry proves to be of major importance for the production of accurately shaped micro cups and cannot be compensated by intentional blank displacement.

Predictive model for disinfection by-product in Alexandria drinking water, northern west of Egypt.

PubMed

Abdullah, Ali M; Hussona, Salah El-dien

2013-10-01

Chlorine has been utilized in the early stages of water treatment processes as disinfectant. Disinfection for drinking water reduces the risk of pathogenic infection but may pose a chemical threat to human health due to disinfection residues and their by-products (DBP) when the organic and inorganic precursors are present in water. In the last two decades, many modeling attempts have been made to predict the occurrence of DBP in drinking water. Models have been developed based on data generated in laboratory-scale and field-scale investigations. The objective of this paper is to develop a predictive model for DBP formation in the Alexandria governorate located at the northern west of Egypt based on field-scale investigations as well as laboratory-controlled experimentations. The present study showed that the correlation coefficient between trihalomethanes (THM) predicted and THM measured was R (2)=0.88 and the minimum deviation percentage between THM predicted and THM measured was 0.8 %, the maximum deviation percentage was 89.3 %, and the average deviation was 17.8 %, while the correlation coefficient between dichloroacetic acid (DCAA) predicted and DCAA measured was R (2)=0.98 and the minimum deviation percentage between DCAA predicted and DCAA measured was 1.3 %, the maximum deviation percentage was 47.2 %, and the average deviation was 16.6 %. In addition, the correlation coefficient between trichloroacetic acid (TCAA) predicted and TCAA measured was R (2)=0.98 and the minimum deviation percentage between TCAA predicted and TCAA measured was 4.9 %, the maximum deviation percentage was 43.0 %, and the average deviation was 16.0 %.

Screen Twice, Cut Once: Assessing the Predictive Validity of Teacher Selection Tools

ERIC Educational Resources Information Center

Goldhaber, Dan; Grout, Cyrus; Huntington-Klein, Nick

2015-01-01

It is well documented that teachers can have profound effects on student outcomes. Empirical estimates find that a one standard deviation increase in teacher quality raises student test achievement by 10 to 25 percent of a standard deviation. More recent evidence shows that the effectiveness of teachers can affect long-term student outcomes, such…

Study of Ionospheric TEC from GPS observations and comparisons with IRI and SPIM model predictions in the low latitude anomaly Indian subcontinental region

NASA Astrophysics Data System (ADS)

Panda, S. K.; Gedam, S. S.; Rajaram, G.

2015-04-01

The present study investigates variation of the ionospheric total electron content (TEC) in the low latitude Indian sub-continental region from the GPS observations and its comparison with the global ionosphere maps (GIMs), standard international reference ionosphere (IRI 2012), and the standard plasmasphere-ionosphere model (SPIM) for the period from November 2011 to October 2012 that corresponds to the progressive phase towards the midst of the solar cycle-24. Observations during quiet period show diurnal maximum of TEC occurring around 14:00-16:00 IST, with relatively broader and longer duration of local maximum at Bangalore and behave reversely towards Delhi. The secondary maximum of TEC was markedly noticeable at Bangalore during the months of March and September, and only in the month of September at Hyderabad and Mumbai. However, the relatively higher TEC during December month than the June is ascribed to the winter anomaly which is more prevalent during the high solar activity periods. The prevailing instability in latitudes of anomaly crest during January 2012 is possibly due to the seasonal variation of lunar tidal effects, modulating the EEJ strength at the equator. The studies covered the period of a strong geomagnetic storm during 6-11 March 2012 (SYM-H: -149 nT) which resulted in positive deviation of GPS-TEC at Bangalore (↑ 20%), Hyderabad (↑ 22%), and Lucknow (↑ 94%) compared to the mean quiet days level. The relatively large deviation of TEC at Lucknow could be attributed to the poleward shifting of the anomaly crest, manifested by enhanced fountain effect at the equator. Studies confirm excellent agreement (80-85%) of GPS-TEC with IGS-GIM at Bangalore and Hyderabad with the exception of the night-time hours (Deviations >50%). However relatively larger deviation of GPS-TEC from GIM-TEC at Delhi could be due to the unavailability of IGS stations in the proximity of the position. Predictions of the SPIM model (extension of IRI up to GPS altitude) exhibit much higher deviation from the in situ GPS observations as well as GIM and IRI outputs during quiet periods. Correspondingly, either of the models (IRI and SPIM) did not respond well to the arrival of the sudden storm commencements (SSCs) during the storm period (6-11 March 2012). When SPIM is used instead of IRI, the overestimation from GPS-TECs are further exaggerated by 13-18% (December solstice), 27-37% (March equinox), 15-31% (June solstice), and 20-32% (September equinox) during peak hours of the period. We attribute the relatively more deviation of the SPIM than the IRI model possibly due to its plasmaspheric extension to the IRI model by adding the Russian SMI model of high latitude characteristics. Hence, we emphasize the further improvement in the model with due consideration of the driving forces at play in the region, for reliable predictions of the low latitude ionosphere.

Cumulants and large deviations of the current through non-equilibrium steady states

NASA Astrophysics Data System (ADS)

Bodineau, Thierry; Derrida, Bernard

2007-06-01

Using a generalisation of detailed balance for systems maintained out of equilibrium by contact with 2 reservoirs at unequal temperatures or at unequal densities, one can recover the fluctuation theorem for the large deviation function of the current. For large diffusive systems, we show how the large deviation function of the current can be computed using a simple additivity principle. The validity of this additivity principle and the occurrence of phase transitions are discussed in the framework of the macroscopic fluctuation theory. To cite this article: T. Bodineau, B. Derrida, C. R. Physique 8 (2007).

Higher-order geodesic deviation for charged particles and resonance induced by gravitational waves

NASA Astrophysics Data System (ADS)

Heydari-Fard, M.; Hasani, S. N.

We generalize the higher-order geodesic deviation for the structure-less test particles to the higher-order geodesic deviation equations of the charged particles [R. Kerner, J. W. van Holten and R. Colistete Jr., Class. Quantum Grav. 18 (2001) 4725]. By solving these equations for charged particles moving in a constant magnetic field in the spacetime of a gravitational wave, we show for both cases when the gravitational wave is parallel and perpendicular to the constant magnetic field, a magnetic resonance appears at wg = Ω. This feature might be useful to detect the gravitational wave with high frequencies.

Importance sampling large deviations in nonequilibrium steady states. I.

PubMed

Ray, Ushnish; Chan, Garnet Kin-Lic; Limmer, David T

2018-03-28

Large deviation functions contain information on the stability and response of systems driven into nonequilibrium steady states and in such a way are similar to free energies for systems at equilibrium. As with equilibrium free energies, evaluating large deviation functions numerically for all but the simplest systems is difficult because by construction they depend on exponentially rare events. In this first paper of a series, we evaluate different trajectory-based sampling methods capable of computing large deviation functions of time integrated observables within nonequilibrium steady states. We illustrate some convergence criteria and best practices using a number of different models, including a biased Brownian walker, a driven lattice gas, and a model of self-assembly. We show how two popular methods for sampling trajectory ensembles, transition path sampling and diffusion Monte Carlo, suffer from exponentially diverging correlations in trajectory space as a function of the bias parameter when estimating large deviation functions. Improving the efficiencies of these algorithms requires introducing guiding functions for the trajectories.

Importance sampling large deviations in nonequilibrium steady states. I

NASA Astrophysics Data System (ADS)

Ray, Ushnish; Chan, Garnet Kin-Lic; Limmer, David T.

2018-03-01

Large deviation functions contain information on the stability and response of systems driven into nonequilibrium steady states and in such a way are similar to free energies for systems at equilibrium. As with equilibrium free energies, evaluating large deviation functions numerically for all but the simplest systems is difficult because by construction they depend on exponentially rare events. In this first paper of a series, we evaluate different trajectory-based sampling methods capable of computing large deviation functions of time integrated observables within nonequilibrium steady states. We illustrate some convergence criteria and best practices using a number of different models, including a biased Brownian walker, a driven lattice gas, and a model of self-assembly. We show how two popular methods for sampling trajectory ensembles, transition path sampling and diffusion Monte Carlo, suffer from exponentially diverging correlations in trajectory space as a function of the bias parameter when estimating large deviation functions. Improving the efficiencies of these algorithms requires introducing guiding functions for the trajectories.

Effect of drivers' age and push button locations on visual time off road, steering wheel deviation and safety perception.

PubMed

Dukic, T; Hanson, L; Falkmer, T

2006-01-15

The study examined the effects of manual control locations on two groups of randomly selected young and old drivers in relation to visual time off road, steering wheel deviation and safety perception. Measures of visual time off road, steering wheel deviations and safety perception were performed with young and old drivers during real traffic. The results showed an effect of both driver's age and button location on the dependent variables. Older drivers spent longer visual time off road when pushing the buttons and had larger steering wheel deviations. Moreover, the greater the eccentricity between the normal line of sight and the button locations, the longer the visual time off road and the larger the steering wheel deviations. No interaction effect between button location and age was found with regard to visual time off road. Button location had an effect on perceived safety: the further away from the normal line of sight the lower the rating.

Effect of stoichiometry on magnetic and transport properties in polycrystalline Y2Ir2O7

NASA Astrophysics Data System (ADS)

Dwivedi, Vinod Kumar; Mukhopadhyay, Soumik

2018-05-01

In this paper we discuss synthesis of polycrystalline Y2Ir2O7 by solid state reaction route. XRD analysis shows deviation from stoichiometry which is also confirmed by SEM-EDX analysis. SEM analysis indicates average particle size ranging from 100 nm to 800 µm. EDX analysis gives clear evidence for deviation of stoichiometry of the product. Magnetic analysis is indicating effect of stoichiometry and showing ferromagnetic interaction unlike antiferromagnetic feature. Electrical resistivity is showing similar behavior as reported earlier and reveals no effect of different size of grains or grain boundaries from room temperature to 125 K.

Prism Adaptation Alters Electrophysiological Markers of Attentional Processes in the Healthy Brain.

PubMed

Martín-Arévalo, Elisa; Laube, Inga; Koun, Eric; Farnè, Alessandro; Reilly, Karen T; Pisella, Laure

2016-01-20

Neglect patients typically show a rightward attentional orienting bias and a strong disengagement deficit, such that they are especially slow in responding to left-sided targets after right-sided cues (Posner et al., 1984). Prism adaptation (PA) can reduce diverse debilitating neglect symptoms and it has been hypothesized that PA's effects are so generalized that they might be mediated by attentional mechanisms (Pisella et al., 2006; Redding and Wallace, 2006). In neglect patients, performance on spatial attention tasks improves after rightward-deviating PA (Jacquin-Courtois et al., 2013). In contrast, in healthy subjects, although there is evidence that leftward-deviating PA induces neglect-like performance on some visuospatial tasks, behavioral studies of spatial attention tasks have mostly yielded negative results (Morris et al., 2004; Bultitude et al., 2013). We hypothesized that these negative behavioral findings might reflect the limitations of behavioral measures in healthy subjects. Here we exploited the sensitivity of event-related potentials to test the hypothesis that electrophysiological markers of attentional processes in the healthy human brain are affected by PA. Leftward-deviating PA generated asymmetries in attentional orienting (reflected in the cue-locked N1) and in attentional disengagement for invalidly cued left targets (reflected in the target-locked P1). This is the first electrophysiological demonstration that leftward-deviating PA in healthy subjects mimics attentional patterns typically seen in neglect patients. Significance statement: Prism adaptation (PA) is a promising tool for ameliorating many deficits in neglect patients and inducing neglect-like behavior in healthy subjects. The mechanisms underlying PA's effects are poorly understood but one hypothesis suggests that it acts by modulating attention. To date, however, there has been no successful demonstration of attentional modulation in healthy subjects. We provide the first electrophysiological evidence that PA acts on attention in healthy subjects by mimicking the attentional pattern typically reported in neglect patients: both a rightward attentional orienting bias (reflected in the cue-locked N1) and a deficit in attentional disengagement from the right hemispace (reflected in the target-locked P1). This study makes an important contribution to refining current models of the mechanisms underlying PA's cognitive effects. Copyright © 2016 the authors 0270-6474/16/361019-12$15.00/0.

Improving student learning via mobile phone video content: Evidence from the BridgeIT India project

NASA Astrophysics Data System (ADS)

Wennersten, Matthew; Quraishy, Zubeeda Banu; Velamuri, Malathi

2015-08-01

Past efforts invested in computer-based education technology interventions have generated little evidence of affordable success at scale. This paper presents the results of a mobile phone-based intervention conducted in the Indian states of Andhra Pradesh and Tamil Nadu in 2012-13. The BridgeIT project provided a pool of audio-visual learning materials organised in accordance with a system of syllabi pacing charts. Teachers of Standard 5 and 6 English and Science classes were notified of the availability of new videos via text messages (SMS), which they downloaded onto their phones using an open-source application and showed, with suggested activities, to students on a TV screen using a TV-out cable. In their evaluation of this project, the authors of this paper found that the test scores of children who experienced the intervention improved by 0.36 standard deviations in English and 0.98 standard deviations in Science in Andhra Pradesh, relative to students in similar classrooms who did not experience the intervention. Differences between treatment and control schools in Tamil Nadu were less marked. The intervention was also cost-effective, relative to other computer-based interventions. Based on these results, the authors argue that is possible to use mobile phones to produce a strong positive and statistically significant effect in terms of teaching and learning quality across a large number of classrooms in India at a lower cost per student than past computer-based interventions.

Hydrogeology from 10,000 ft below: lessons learned in applying pulse testing for leakage detection in a carbon sequestration formation

NASA Astrophysics Data System (ADS)

Sun, A. Y.; Lu, J.; Hovorka, S. D.; Freifeld, B. M.; Islam, A.

2015-12-01

Monitoring techniques capable of deep subsurface detection are desirable for early warning and leakage pathway identification in geologic carbon storage formations. This work investigates the feasibility of a leakage detection technique based on pulse testing, which is a traditional hydrogeological characterization tool. In pulse testing, the monitoring reservoir is stimulated at a fixed frequency and the acquired pressure perturbation signals are analyzed in the frequency domain to detect potential deviations in the reservoir's frequency domain response function. Unlike traditional time-domain analyses, the frequency-domain analysis aims to minimize the interference of reservoir noise by imposing coded injection patterns such that the reservoir responses to injection can be uniquely determined. We have established the theoretical basis of the approach in previous work. Recently, field validation of this pressure-based, leakage detection technique was conducted at a CO2-EOR site located in Mississippi, USA. During the demonstration, two sets of experiments were performed using 90-min and 150-min pulsing periods, for both with and without leak scenarios. Because of the lack of pre-existing leakage pathways, artificial leakage CO2 was simulated by rate-controlled venting from one of the monitoring wells. Our results show that leakage events caused a significant deviation in the amplitude of the frequency response function, indicating that pulse testing may be used as a cost-effective monitoring technique with a strong potential for automation.

Gamma ray sources observation with the ARGO-YBJ detector

NASA Astrophysics Data System (ADS)

Vernetto, S.; ARGO-YBJ Collaboration

2011-02-01

In this paper we report on the observations of TeV gamma ray sources performed by the air shower detector ARGO-YBJ. The objects studied in this work are the blazar Markarian 421 and the extended galactic source MGROJ1908+06, monitored during ~2 years of operation. Mrk421 has been detected by ARGO-YBJ with a statistical significance of ~11 standard deviations. The observed TeV emission was highly variable, showing large enhancements of the flux during active periods. The study of the spectral behaviour during flares revealed a positive correlation of the hardness with the flux, as already reported in the past by the Whipple telescope, suggesting that this is a long term property of the source. ARGO-YBJ observed a strong correlation between TeV gamma rays and the X-ray flux measured by RXTM/ASM and SWIFT/BAT during the whole period, with a time lag compatible with zero, supporting the one-zone SSC model to describe the emission mechanism. MGROJ1908+06 has been detected by ARGO-YBJ with ~5 standard deviation of significance. From our data the source appears extended and the measured extension is σext = 0.48° --> σext = 0.48° -0.28+0.26 --> -0.28+0.26, in agreement with a previous HESS observation. The average flux is in marginal agreement with that reported by MILAGRO, but significantly higher than that obtained by HESS, suggesting a possible flux variability.

Role of 6-Mercaptopurine in the potential therapeutic targets DNA base pairs and G-quadruplex DNA: insights from quantum chemical and molecular dynamics simulations.

PubMed

Radhika, R; Shankar, R; Vijayakumar, S; Kolandaivel, P

2018-05-01

The theoretical studies on DNA with the anticancer drug 6-Mercaptopurine (6-MP) are investigated using theoretical methods to shed light on drug designing. Among the DNA base pairs considered, 6-MP is stacked with GC with the highest interaction energy of -46.19 kcal/mol. Structural parameters revealed that structure of the DNA base pairs is deviated from the planarity of the equilibrium position due to the formation of hydrogen bonds and stacking interactions with 6-MP. These deviations are verified through the systematic comparison between X-H bond contraction and elongation and the associated blue shift and red shift values by both NBO analysis and vibrational analysis. Bent's rule is verified for the C-H bond contraction in the 6-MP interacted base pairs. The AIM results disclose that the higher values of electron density (ρ) and Laplacian of electron density (∇ 2 ρ) indicate the increased overlap between the orbitals that represent the strong interaction and positive values of the total electron density show the closed-shell interaction. The relative sensitivity of the chemical shift values for the DNA base pairs with 6-MP is investigated to confirm the hydrogen bond strength. Molecular dynamics simulation studies of G-quadruplex DNA d(TGGGGT) 4 with 6-MP revealed that the incorporation of 6-MP appears to cause local distortions and destabilize the G-quadruplex DNA.

Upwelling characteristics in the Gulf of Finland (Baltic Sea) as revealed by Ferrybox measurements in 2007-2013

NASA Astrophysics Data System (ADS)

Kikas, Villu; Lips, Urmas

2016-07-01

Ferrybox measurements have been carried out between Tallinn and Helsinki in the Gulf of Finland (Baltic Sea) on a regular basis since 1997. The system measures autonomously water temperature, salinity, chlorophyll a fluorescence and turbidity and takes water samples for further analyses at a predefined time interval. We aimed to show how the Ferrybox technology could be used to study the coastal upwelling events in the Gulf of Finland. Based on the introduced upwelling index and related criteria, 33 coastal upwelling events were identified in May-September 2007-2013. The number of events, as well as the frequency of their occurrence and intensity expressed as a sum of daily average temperature deviations in the 20 km wide coastal area, were almost equal near the northern and southern coasts. Nevertheless, the wind impulse, which was needed to generate upwelling events of similar intensity, differed between the northern and southern coastal areas. It is suggested that the general thermohaline structure adapted to the prevailing forcing and the estuarine character of the basin weaken the upwelling created by the westerly to southwesterly (up-estuary) winds and strengthen the upwelling created by the easterly to northeasterly (down-estuary) winds. Two types of upwelling events were identified - one characterized by a strong temperature front and the other revealing gradual decrease in temperature from the open sea to the coastal area, with maximum temperature deviation close to the shore.

Glide path preparation in S-shaped canals with rotary pathfinding nickel-titanium instruments.

PubMed

Ajuz, Natasha C C; Armada, Luciana; Gonçalves, Lucio S; Debelian, Gilberto; Siqueira, José F

2013-04-01

This study compared the incidence of deviation along S-shaped (double-curved) canals after glide path preparation with 2 nickel-titanium (NiTi) rotary pathfinding instruments and hand K-files. S-shaped canals from 60 training blocks were filled with ink, and preinstrumentation images were obtained by using a stereomicroscope. Glide path preparation was performed by an endodontist who used hand stainless steel K-files (up to size 20), rotary NiTi PathFile instruments (up to size 19), or rotary NiTi Scout RaCe instruments (up to size 20). Postinstrumentation images were taken by using exactly the same conditions as for the preinstrumentation images, and both pictures were superimposed. Differences along the S-shaped canal for the mesial and distal aspects were measured to evaluate the occurrence of deviation. Intragroup analysis showed that all instruments promoted some deviation in virtually all levels. Overall, regardless of the group, deviations were observed in the mesial wall at the canal terminus and at levels 4, 5, 6 and 7 mm and in the distal wall at levels 1, 2, and 3 mm. These levels corresponded to the inner walls of each curvature. Both rotary NiTi instruments performed significantly better than hand K-files at all levels (P < .05), except for PathFiles at the 0-mm level. ScoutRaCe instruments showed significantly better results than PathFiles at levels 0, 2, 3, 5, and 6 mm (P < .05). Findings suggest that rotary NiTi instruments are suitable for adequate glide path preparation because they promoted less deviation from the original canal anatomy when compared with hand-operated instruments. Of the 2 rotary pathfinding instruments, Scout RaCe showed an overall significantly better performance. Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Error detection capability of a novel transmission detector: a validation study for online VMAT monitoring.

PubMed

Pasler, Marlies; Michel, Kilian; Marrazzo, Livia; Obenland, Michael; Pallotta, Stefania; Björnsgard, Mari; Lutterbach, Johannes

2017-09-01

The purpose of this study was to characterize a new single large-area ionization chamber, the integral quality monitor system (iRT, Germany), for online and real-time beam monitoring. Signal stability, monitor unit (MU) linearity and dose rate dependence were investigated for static and arc deliveries and compared to independent ionization chamber measurements. The dose verification capability of the transmission detector system was evaluated by comparing calculated and measured detector signals for 15 volumetric modulated arc therapy plans. The error detection sensitivity was tested by introducing MLC position and linac output errors. Deviations in dose distributions between the original and error-induced plans were compared in terms of detector signal deviation, dose-volume histogram (DVH) metrics and 2D γ-evaluation (2%/2 mm and 3%/3 mm). The detector signal is linearly dependent on linac output and shows negligible (<0.4%) dose rate dependence up to 460 MU min -1 . Signal stability is within 1% for cumulative detector output; substantial variations were observed for the segment-by-segment signal. Calculated versus measured cumulative signal deviations ranged from  -0.16%-2.25%. DVH, mean 2D γ-value and detector signal evaluations showed increasing deviations with regard to the respective reference with growing MLC and dose output errors; good correlation between DVH metrics and detector signal deviation was found (e.g. PTV D mean : R 2   =  0.97). Positional MLC errors of 1 mm and errors in linac output of 2% were identified with the transmission detector system. The extensive tests performed in this investigation show that the new transmission detector provides a stable and sensitive cumulative signal output and is suitable for beam monitoring during patient treatment.

Validation of 10 years of SAO OMI Ozone Profiles with Ozonesonde and MLS Observations

NASA Astrophysics Data System (ADS)

Huang, G.; Liu, X.; Chance, K.; Bhartia, P. K.

2015-12-01

To evaluate the accuracy and long-term stability of the SAO OMI ozone profile product, we validate ~10 years of ozone profile product (Oct. 2004-Dec. 2014) against collocated ozonesonde and MLS data. Ozone profiles as well stratospheric, tropospheric, lower tropospheric ozone columns are compared with ozonesonde data for different latitude bands, and time periods (e.g., 2004-2008/2009-2014 for without/with row anomaly. The mean biases and their standard deviations are also assessed as a function of time to evaluate the long-term stability and bias trends. In the mid-latitude and tropical regions, OMI generally shows good agreement with ozonesonde observations. The mean ozone profile biases are generally within 6% with up to 30% standard deviations. The biases of stratospheric ozone columns (SOC) and tropospheric ozone columns (TOC) are -0.3%-2.2% and -0.2%-3%, while standard deviations are 3.9%-5.8% and 14.4%-16.0%, respectively. However, the retrievals during 2009-2014 show larger standard deviations and larger temporal variations; the standard deviations increase by ~5% in the troposphere and ~2% in the stratosphere. Retrieval biases at individual levels in the stratosphere and upper troposphere show statistically significant trends and different trends for 2004-2008 and 2009-2014 periods. The trends in integrated ozone partial columns are less significant due to cancellation from various layers, except for significant trend in tropical SOC. These results suggest the need to perform time dependent radiometric calibration to maintain the long-term stability of this product. Similarly, we are comparing the OMI stratospheric ozone profiles and SOC with collocated MLS data, and the results will be reported.

Error detection capability of a novel transmission detector: a validation study for online VMAT monitoring

NASA Astrophysics Data System (ADS)

Pasler, Marlies; Michel, Kilian; Marrazzo, Livia; Obenland, Michael; Pallotta, Stefania; Björnsgard, Mari; Lutterbach, Johannes

2017-09-01

The purpose of this study was to characterize a new single large-area ionization chamber, the integral quality monitor system (iRT, Germany), for online and real-time beam monitoring. Signal stability, monitor unit (MU) linearity and dose rate dependence were investigated for static and arc deliveries and compared to independent ionization chamber measurements. The dose verification capability of the transmission detector system was evaluated by comparing calculated and measured detector signals for 15 volumetric modulated arc therapy plans. The error detection sensitivity was tested by introducing MLC position and linac output errors. Deviations in dose distributions between the original and error-induced plans were compared in terms of detector signal deviation, dose-volume histogram (DVH) metrics and 2D γ-evaluation (2%/2 mm and 3%/3 mm). The detector signal is linearly dependent on linac output and shows negligible (<0.4%) dose rate dependence up to 460 MU min-1. Signal stability is within 1% for cumulative detector output; substantial variations were observed for the segment-by-segment signal. Calculated versus measured cumulative signal deviations ranged from  -0.16%-2.25%. DVH, mean 2D γ-value and detector signal evaluations showed increasing deviations with regard to the respective reference with growing MLC and dose output errors; good correlation between DVH metrics and detector signal deviation was found (e.g. PTV D mean: R 2  =  0.97). Positional MLC errors of 1 mm and errors in linac output of 2% were identified with the transmission detector system. The extensive tests performed in this investigation show that the new transmission detector provides a stable and sensitive cumulative signal output and is suitable for beam monitoring during patient treatment.

Accuracy of Digitally Fabricated Wax Denture Bases and Conventional Completed Complete Dentures.

PubMed

Stawarczyk, Bogna; Lümkemann, Nina; Eichberger, Marlis; Wimmer, Timea

2017-12-19

The purpose of this investigation was to analyze the accuracy of digitally fabricated wax trial dentures and conventionally finalized complete dentures in comparison to a surface tessellation language (STL)-dataset. A generated data set for the denture bases and the tooth sockets was used, converted into STL-format, and saved as reference. Five mandibular and 5 maxillary denture bases were milled from wax blanks and denture teeth were waxed into their tooth sockets. Each complete denture was checked on fit, waxed onto the dental cast, and digitized using an optical laboratory scanning device. The complete dentures were completed conventionally using the injection method, finished, and scanned. The resulting STL-datasets were exported into the three-dimensional (3D) software GOM Inspect. Each of the 5 mandibular and 5 maxillary complete dentures was aligned with the STL- and the wax trial denture dataset. Alignment was performed based on a best-fit algorithm. A three-dimensional analysis of the spatial divergences in x -, y - and z -axes was performed by the 3D software and visualized in a color-coded illustration. The mean positive and negative deviations between the datasets were calculated automatically. In a direct comparison between maxillary wax trial dentures and complete dentures, complete dentures showed higher deviations from the STL-dataset than the wax trial dentures. The deviations occurred in the area of the teeth as well as in the distal area of the denture bases. In contrast, the highest deviations in both the mandibular wax trial dentures and the mandibular complete dentures were observed in the distal area. The complete dentures showed higher deviations on the occlusal surfaces of the teeth compared to the wax dentures. Computer-aided design/computer-aided manufacturing (CAD/CAM)-fabricated wax dentures exhibited fewer deviations from the STL-reference than the complete dentures. The deviations were significantly greater in the vicinity of the denture teeth area and the bases. The conventional transfer of CAD/CAM-fabricated wax dentures into acrylic resin leads to the highest deviations from the STL-reference.

Method of surface error visualization using laser 3D projection technology

NASA Astrophysics Data System (ADS)

Guo, Lili; Li, Lijuan; Lin, Xuezhu

2017-10-01

In the process of manufacturing large components, such as aerospace, automobile and shipping industry, some important mold or stamped metal plate requires precise forming on the surface, which usually needs to be verified, if necessary, the surface needs to be corrected and reprocessed. In order to make the correction of the machined surface more convenient, this paper proposes a method based on Laser 3D projection system, this method uses the contour form of terrain contour, directly showing the deviation between the actually measured data and the theoretical mathematical model (CAD) on the measured surface. First, measure the machined surface to get the point cloud data and the formation of triangular mesh; secondly, through coordinate transformation, unify the point cloud data to the theoretical model and calculate the three-dimensional deviation, according to the sign (positive or negative) and size of the deviation, use the color deviation band to denote the deviation of three-dimensional; then, use three-dimensional contour lines to draw and represent every coordinates deviation band, creating the projection files; finally, import the projection files into the laser projector, and make the contour line projected to the processed file with 1:1 in the form of a laser beam, compare the Full-color 3D deviation map with the projection graph, then, locate and make quantitative correction to meet the processing precision requirements. It can display the trend of the machined surface deviation clearly.

Human influences on streamflow drought characteristics in England and Wales

NASA Astrophysics Data System (ADS)

Tijdeman, Erik; Hannaford, Jamie; Stahl, Kerstin

2018-02-01

Human influences can affect streamflow drought characteristics and propagation. The question is where, when and why? To answer these questions, the impact of different human influences on streamflow droughts were assessed in England and Wales, across a broad range of climate and catchments conditions. We used a dataset consisting of catchments with near-natural flow as well as catchments for which different human influences have been indicated in the metadata (Factors Affecting Runoff) of the UK National River Flow Archive (NRFA). A screening approach was applied on the streamflow records to identify human-influenced records with drought characteristics that deviated from those found for catchments with near-natural flow. Three different deviations were considered, specifically deviations in (1) the relationship between streamflow drought duration and the base flow index, BFI (specifically, BFIHOST, the BFI predicted from the hydrological properties of soils), (2) the correlation between streamflow and precipitation and (3) the temporal occurrence of streamflow droughts compared to precipitation droughts, i.e. an increase or decrease in streamflow drought months relative to precipitation drought months over the period of record. The identified deviations were then related to the indicated human influences. Results showed that the majority of catchments for which human influences were indicated did not show streamflow drought characteristics that deviated from those expected under near-natural conditions. For the catchments that did show deviating streamflow drought characteristics, prolonged streamflow drought durations were found in some of the catchments affected by groundwater abstractions. Weaker correlations between streamflow and precipitation were found for some of the catchments with reservoirs, water transfers or groundwater augmentation schemes. An increase in streamflow drought occurrence towards the end of their records was found for some of the catchments affected by groundwater abstractions and a decrease in streamflow drought occurrence for some of the catchments with either reservoirs or groundwater abstractions. In conclusion, the proposed screening approaches were sometimes successful in identifying streamflow records with deviating drought characteristics that are likely related to different human influences. However, a quantitative attribution of the impact of human influences on streamflow drought characteristics requires more detailed case-by-case information about the type and degree of all different human influences. Given that, in many countries, such information is often not readily accessible, the approaches adopted here could provide useful in targeting future efforts. In England and Wales specifically, the catchments with deviating streamflow drought characteristics identified in this study could serve as the starting point of detailed case study research.

Radiogenomic analysis of lower grade glioma: a pilot multi-institutional study shows an association between quantitative image features and tumor genomics

NASA Astrophysics Data System (ADS)

Mazurowski, Maciej A.; Clark, Kal; Czarnek, Nicholas M.; Shamsesfandabadi, Parisa; Peters, Katherine B.; Saha, Ashirbani

2017-03-01

Recent studies showed that genomic analysis of lower grade gliomas can be very effective for stratification of patients into groups with different prognosis and proposed specific genomic classifications. In this study, we explore the association of one of those genomic classifications with imaging parameters to determine whether imaging could serve a similar role to genomics in cancer patient treatment. Specifically, we analyzed imaging and genomics data for 110 patients from 5 institutions from The Cancer Genome Atlas and The Cancer Imaging Archive datasets. The analyzed imaging data contained preoperative FLAIR sequence for each patient. The images were analyzed using the in-house algorithms which quantify 2D and 3D aspects of the tumor shape. Genomic data consisted of a cluster of clusters classification proposed in a very recent and leading publication in the field of lower grade glioma genomics. Our statistical analysis showed that there is a strong association between the tumor cluster-of-clusters subtype and two imaging features: bounding ellipsoid volume ratio and angular standard deviation. This result shows high promise for the potential use of imaging as a surrogate measure for genomics in the decision process regarding treatment of lower grade glioma patients.

Will reducing sugar-sweetened beverage consumption reduce obesity? Evidence supporting conjecture is strong, but evidence when testing effect is weak

PubMed Central

Kaiser, Kathryn A.; Shikany, James M.; Keating, Karen D.; Allison, David B.

2014-01-01

We provide arguments to the debate question and update a previous meta-analysis with recently published studies on effects of sugar-sweetened beverages (SSBs) on body weight/composition indices (BWIs). We abstracted data from randomized controlled trials examining effects of consumption of SSBs on BWIs. Six new studies met these criteria: 1) human trials, 2) 3 weeks duration, 3) random assignment to conditions differing only in consumption of SSBs, and 4) including a BWI outcome. Updated meta-analysis of a total of seven studies that added SSBs to persons’ diets showed dose-dependent increases in weight. Updated meta-analysis of eight studies attempting to reduce SSB consumption showed an equivocal effect on BWIs in all randomized subjects. When limited to subjects overweight at baseline, meta-analysis showed a significant effect of roughly 0.25 standard deviations (more weight loss/less weight gain) relative to controls. Evidence to date is equivocal in showing that decreasing SSB consumption will reduce the prevalence of obesity. Although new evidence suggests that an effect may yet be demonstrable in some populations, the integrated effect size estimate remains very small and of equivocal statistical significance. Problems in this research area and suggestions for future research are highlighted. PMID:23742715

Aqueous solubility of diclofenac diethylamine in the presence of pharmaceutical additives: a comparative study with diclofenac sodium.

PubMed

Khalil, E; Najjar, S; Sallam, A

2000-04-01

Aqueous solubility of diclofenac diethylamine (DDEA), a nonsteroidal anti-inflammatory drug currently formulated as a topical emulgel, was studied in the presence of pharmaceutical additives and compared with diclofenac sodium (DS). Electrolytes at low concentrations exhibited a salting-in effect on DDEA with peak solubility that was attributed to the association of DDEA into micelles, followed by a salting-out effect at higher concentrations, by which structure formation by DDEA molecules increased and precipitation occurred. For DS, which is not capable of forming micelles, the salting-out effect was dominant due to the common ion effect. Cosolvents displayed significant enhancement in solubility of both salts except glycerol, which showed a slight increase in solubility of DDEA and a decrease in solubility of DS due to transformation into the less soluble hydrate form. Ethanol and polyethylene glycol (PEG) 400 cosolvent systems at all concentrations showed positive deviations from the log-linear solubility equation. In the case of propylene glycol (PG) cosolvent systems, negative deviations were observed at low volume fractions of cosolvent, while positive deviations were observed at high volume fractions of cosolvent for DS and DDEA. The parent drug, being less ionizable and highly nonpolar, showed negative deviations up to 90% PG content. Thus, the positive deviations for DS and DDEA could be attributed to the more ionizable carboxylic group and its higher ability for hydrogen bonding at higher fractions of cosolvent. Polyvinylpyrrolidone (PVP) and PEG4000 or PEG6000 enhanced the solubility of DS and DDEA, with PVP exerting higher solubilizing efficiency and DS showing better solubility than DDEA. Solubilities of DS in Tween 80 (T80) and Pluronic F-127 (PF127) aqueous solutions were almost similar, while the solubility of DDEA in the presence of T80 was higher than the solubility in the presence of PF127. DS appeared to be located more in the polyoxyethylene mantle of the micelles, while DDEA was located more in the core of the micelles.

Cone-Beam Computed Tomography Assessment of Lower Facial Asymmetry in Unilateral Cleft Lip and Palate and Non-Cleft Patients with Class III Skeletal Relationship.

PubMed

Lin, Yifan; Chen, Gui; Fu, Zhen; Ma, Lian; Li, Weiran

2015-01-01

To evaluate, using cone-beam computed tomography (CBCT), both the condylar-fossa relationships and the mandibular and condylar asymmetries between unilateral cleft lip and palate (UCLP) patients and non-cleft patients with class III skeletal relationship, and to investigate the factors of asymmetry contributing to chin deviation. The UCLP and non-cleft groups consisted of 30 and 40 subjects, respectively, in mixed dentition with class III skeletal relationships. Condylar-fossa relationships and the dimensional and positional asymmetries of the condyles and mandibles were examined using CBCT. Intra-group differences were compared between two sides in both groups using a paired t-test. Furthermore, correlations between each measurement and chin deviation were assessed. It was observed that 90% of UCLP and 67.5% of non-cleft subjects had both condyles centered, and no significant asymmetry was found. The axial angle and the condylar center distances to the midsagittal plane were significantly greater on the cleft side than on the non-cleft side (P=0.001 and P=0.028, respectively) and were positively correlated with chin deviation in the UCLP group. Except for a larger gonial angle on the cleft side, the two groups presented with consistent asymmetries showing shorter mandibular bodies and total mandibular lengths on the cleft (deviated) side. The average chin deviation was 1.63 mm to the cleft side, and the average absolute chin deviation was significantly greater in the UCLP group than in the non-cleft group (P=0.037). Compared with non-cleft subjects with similar class III skeletal relationships, the subjects with UCLP showed more severe lower facial asymmetry. The subjects with UCLP presented with more asymmetrical positions and rotations of the condyles on axial slices, which were positively correlated with chin deviation.

Statistical characteristics of cloud variability. Part 1: Retrieved cloud liquid water path at three ARM sites

NASA Astrophysics Data System (ADS)

Huang, Dong; Campos, Edwin; Liu, Yangang

2014-09-01

Statistical characteristics of cloud variability are examined for their dependence on averaging scales and best representation of probability density function with the decade-long retrieval products of cloud liquid water path (LWP) from the tropical western Pacific (TWP), Southern Great Plains (SGP), and North Slope of Alaska (NSA) sites of the Department of Energy's Atmospheric Radiation Measurement Program. The statistical moments of LWP show some seasonal variation at the SGP and NSA sites but not much at the TWP site. It is found that the standard deviation, relative dispersion (the ratio of the standard deviation to the mean), and skewness all quickly increase with the averaging window size when the window size is small and become more or less flat when the window size exceeds 12 h. On average, the cloud LWP at the TWP site has the largest values of standard deviation, relative dispersion, and skewness, whereas the NSA site exhibits the least. Correlation analysis shows that there is a positive correlation between the mean LWP and the standard deviation. The skewness is found to be closely related to the relative dispersion with a correlation coefficient of 0.6. The comparison further shows that the lognormal, Weibull, and gamma distributions reasonably explain the observed relationship between skewness and relative dispersion over a wide range of scales.

Statistical characteristics of cloud variability. Part 1: Retrieved cloud liquid water path at three ARM sites: Observed cloud variability at ARM sites

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

Huang, Dong; Campos, Edwin; Liu, Yangang

2014-09-17

Statistical characteristics of cloud variability are examined for their dependence on averaging scales and best representation of probability density function with the decade-long retrieval products of cloud liquid water path (LWP) from the tropical western Pacific (TWP), Southern Great Plains (SGP), and North Slope of Alaska (NSA) sites of the Department of Energy’s Atmospheric Radiation Measurement Program. The statistical moments of LWP show some seasonal variation at the SGP and NSA sites but not much at the TWP site. It is found that the standard deviation, relative dispersion (the ratio of the standard deviation to the mean), and skewness allmore » quickly increase with the averaging window size when the window size is small and become more or less flat when the window size exceeds 12 h. On average, the cloud LWP at the TWP site has the largest values of standard deviation, relative dispersion, and skewness, whereas the NSA site exhibits the least. Correlation analysis shows that there is a positive correlation between the mean LWP and the standard deviation. The skewness is found to be closely related to the relative dispersion with a correlation coefficient of 0.6. The comparison further shows that the log normal, Weibull, and gamma distributions reasonably explain the observed relationship between skewness and relative dispersion over a wide range of scales.« less

Approaching sub-50 nanoradian measurements by reducing the saw-tooth deviation of the autocollimator in the Nano-Optic-Measuring Machine

NASA Astrophysics Data System (ADS)

Qian, Shinan; Geckeler, Ralf D.; Just, Andreas; Idir, Mourad; Wu, Xuehui

2015-06-01

Since the development of the Nano-Optic-Measuring Machine (NOM), the accuracy of measuring the profile of an optical surface has been enhanced to the 100-nrad rms level or better. However, to update the accuracy of the NOM system to sub-50 nrad rms, the large saw-tooth deviation (269 nrad rms) of an existing electronic autocollimator, the Elcomat 3000/8, must be resolved. We carried out simulations to assess the saw-tooth-like deviation. We developed a method for setting readings to reduce the deviation to sub-50 nrad rms, suitable for testing plane mirrors. With this method, we found that all the tests conducted in a slowly rising section of the saw-tooth show a small deviation of 28.8 to <40 nrad rms. We also developed a dense-measurement method and an integer-period method to lower the saw-tooth deviation during tests of sphere mirrors. Further research is necessary for formulating a precise test for a spherical mirror. We present a series of test results from our experiments that verify the value of the improvements we made.

Hydrologic response to modeled snowmelt input in alpine catchments in the Southwestern United States

NASA Astrophysics Data System (ADS)

Driscoll, J. M.; Molotch, N. P.; Jepsen, S. M.; Meixner, T.; Williams, M. W.; Sickman, J. O.

2012-12-01

Snowmelt from high elevation catchments is the primary source of water resources in the Southwestern United States. Timing and duration of snowmelt and resulting catchment response can show the physical and chemical importance of storage at the catchment scale. Storage of waters in subsurface materials provides a physical and chemical buffer to hydrologic input variability. We expect the hydrochemistry of catchments with less storage capacity will more closely reflect input waters than a catchment with more storage and therefore more geochemical evolution of waters. Two headwater catchments were compared for this study; Emerald Lake Watershed (ELW) in the southern Sierra Nevada and Green Lake 4 (GL4) in the Colorado Front Range. These sites have geochemically similar granitic terrane, and negligible evaporation and transpiration due to their high-elevation setting. Eleven years of data (1996-2006) from spatially-distributed snowmelt models were spatially and temporally aggregated to generate daily values of snowmelt volume for each catchment area. Daily storage flux was calculated as the difference between snowmelt input and catchment outflow at a daily timestep, normalized to the catchment area. Daily snowmelt values in GL4 are more consistent (the annual standard deviation ranged from 0.19 to 0.76 cm) than the daily snowmelt in ELW (0.60 to 1.04 cm). Outflow follows the same trend, with an even narrower range of standard deviations from GL4 (0.27 to 0.54 cm) compared to the standard deviation of outflow in ELW (0.38 to 0.98 cm). The dampening of the input variability could be due to storage in the catchment; the larger effect would mean a larger storage capacity in the catchment. Calculations of storage flux (the input snowmelt minus the output catchment discharge) show the annual sum of water into storage in ELW ranges from -0.9200 to 1.1124 meters, in GL4 the ranger is narrower, from -0.655 to 0.0992 meters. Cumulative storage for each year can be negative (more water leaving the system than entering; storage loss) or positive (more water coming into the system than leaving; storage gain). The cumulative storage for all years in GL4 show a similar positive trend from day of year 60 through 150, followed by a decrease to the end of the snowmelt season. Only two years (1997 and 2005) in GL4 were calculated to cumulatively gain storage water, the other nine years lost stored water to outflow. The cumulative storage annual data in ELW do not show as strong of a trend for all years. ELW also a different distribution of cumulative storage values; with four years showing a cumulative loss and seven years showing a gain in stored water. This could show a depletion of stored water, an underestimate of snowmelt or a connection to deeper flowpaths. Mass-balance inverse geochemical models will be used to determine the hydrochemical connectivity or lack of connectivity of snowmelt to outflow relative to the physical calculations. Initial hydrochemical results show generally higher concentrations of solutes from GL4 outflow, which may show more contribution from stored waters.

Deviations of the visual upright in three dimensions in disorders of the brainstem: a clinical exploration.

PubMed

Frisén, Lars

2010-12-01

Deviations of the subjective visual vertical in the roll or fronto-parallel plane occur commonly in disorders of the brainstem and have been extensively explored. In contrast, little is known about deviations in other directions. The present retrospective study focused on deviations in the pitch (sagittal) direction in 176 patients with a wide variety of disorders. The test task was to set a self-illuminated rod in the apparent upright position, in total darkness. Abnormal results (outside ± 4°) were recorded in 58% of the subjects. Negative (top backward) deviations were the most common, particularly with mass lesions in the pineal region, obstructive hydrocephalus, cerebellar lesions and crowding at the craniocervical junction. Positive and negative deviations were about equally common with focal intra-axial lesions. Negative deviations appeared related to dorsal locations of lesions and vice versa. Normal pressure hydrocephalus, Parkinson's disease and progressive supranuclear palsy were associated with smaller deviations, without a clear directional preponderance, and a larger individual variability. Most subjects lacked overt clinical corollaries. The most common ocular signs were aqueduct syndromes (n = 17) and ocular tilt reactions (n = 12), which were associated with deviations in 47 and 92% of instances, respectively. Subjective corollaries of deviation were never reported, not even by those subjects who showed a dramatic improvement upon resolution of the underlying condition. Deviations were also assessed in roll in a subgroup of 40 patients with focal lesions. Thirty subjects returned abnormal results: 13% in roll, 47% in pitch and 40% in pitch and roll. The direction of roll deviation appeared primarily related to laterality, with clockwise deviations with right-sided lesions and vice versa. All subjects with ocular tilt reactions had combined pitch and roll deviations, implying a common neural substrate. Correlation analyses, geometrical modelling and experimental self-observations indicated that deviations in pitch were attributable to cyclotorsional asymmetries between the eyes. The frequent co-existence of abnormal pitch and roll results implies that the true axis of deviation in focal brainstem disorders commonly falls outside traditional reference planes. The term 'visual upright in three dimensions' is suggested to identify unrestricted measurements, preserving the established term 'visual vertical' for measurements confined to the roll plane. Assessment of the visual upright in three dimensions provides a new, quantitative angle on brainstem disorders. The test appears useful for identifying a ubiquitous yet clinically silent feature of brainstem disease and also for monitoring the evolution of underlying conditions. More detailed explorations appear well motivated.

Feynman variance for neutrons emitted from photo-fission initiated fission chains - a systematic simulation for selected speacal nuclear materials

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

Soltz, R. A.; Danagoulian, A.; Sheets, S.

Theoretical calculations indicate that the value of the Feynman variance, Y2F for the emitted distribution of neutrons from ssionable exhibits a strong monotonic de- pendence on a the multiplication, M, of a quantity of special nuclear material. In 2012 we performed a series of measurements at the Passport Inc. facility using a 9- MeV bremsstrahlung CW beam of photons incident on small quantities of uranium with liquid scintillator detectors. For the set of objects studies we observed deviations in the expected monotonic dependence, and these deviations were later con rmed by MCNP simulations. In this report, we modify the theorymore » to account for the contri- bution from the initial photo- ssion and benchmark the new theory with a series of MCNP simulations on DU, LEU, and HEU objects spanning a wide range of masses and multiplication values.« less

Influence of magnetization on the applied magnetic field in various AMR regenerators

NASA Astrophysics Data System (ADS)

Mira, A.; de Larochelambert, T.; Espanet, C.; Giurgea, S.; Nika, P.; Bahl, C. R. H.; Bjørk, R.; Nielsen, K. K.

2017-10-01

The aim of this work is to assess the influence of a magnetic sample on the applied magnetic field inside the air gap of a magnetic circuit. Different magnetic sources including an electromagnet, a permanent magnet in a soft ferromagnetic toroidal yoke, as well as 2D and 3D Halbach cylinders are considered, using a numerical model. Gadolinium is chosen as magnetic material for the sample, due to its strong magnetocaloric properties and its wide use in magnetic refrigeration prototypes. We find that using uniform theoretical demagnetizing factors for cylinders or spheres results in a deviation of less than 2% in the calculation of internal magnetic fields at temperatures above the Curie point of gadolinium. Below the Curie point, a stronger magnetization of the cylinders and spheres leads to a larger deviation which can reach 8% when using uniform demagnetizing factors for internal magnetic field calculations.

THE EFFECTS OF ANGULAR MOMENTUM ON HALO PROFILES

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

Lentz, Erik W; Rosenberg, Leslie J; Quinn, Thomas R, E-mail: lentze@phys.washington.edu, E-mail: ljrosenberg@phys.washington.edu, E-mail: trq@astro.washington.edu

2016-05-10

The near universality of DM halo density profiles provided by N -body simulations proved to be robust against changes in total mass density, power spectrum, and some forms of initial velocity dispersion. Here we study the effects of coherently spinning up an isolated DM-only progenitor on halo structure. Halos with spins within several standard deviations of the simulated mean ( λ ≲ 0.20) produce profiles with negligible deviations from the universal form. Only when the spin becomes quite large ( λ ≳ 0.20) do departures become evident. The angular momentum distribution also exhibits a near universal form, which is alsomore » independent of halo spin up to λ ≲ 0.20. A correlation between these epidemic profiles and the presence of a strong bar in the virialized halo is also observed. These bar structures bear resemblance to the radial orbit instability in the rotationless limit.« less

Hydrodynamics of primordial black hole formation

NASA Technical Reports Server (NTRS)

Nadezhin, D. K.; Novikov, I. D.; Polnarev, A. G.

1979-01-01

The hydrodynamic picture of the formation of primordial black holes (PBH) at the early stages of expansion of the Universe is considered. It is assumed that close to singularity, expansion occurs in a quasi-isotropic way. Using an EVM, a spherically symmetrical nonlinear problem of the evolution of primary strong deviation from the Fridman solution was solved. What these deviations must be, so that the formation of PBH occurred was clarified. Attention was devoted to the role of pressure gradients. It is pointed out that at the moment of formation of PBH, only a small part of matter enters into it, primarily the component of perturbation. It is also pointed out that at this moment, the mass of PBH essentially is smaller than the mass considered within the cosmic horizon. The possibility of changing the mass of the PBH as a result of accretion is analyzed.

Quantification of processing artifacts in textile composites

NASA Technical Reports Server (NTRS)

Pastore, Christopher M.

1993-01-01

One of the greatest difficulties in developing detailed models of the mechanical response of textile reinforced composites is an accurate model of the reinforcing elements. In the case of elastic property prediction, the variation of fiber position may not have a critical role in performance. However, when considering highly localized stress events, such as those associated with cracks and holes, the exact position of the reinforcement probably dominates the failure mode. Models were developed for idealized reinforcements which provide an insight into the local behavior. However, even casual observations of micrographical images reveals that the actual material deviates strongly from the idealized models. Some of the deviations and causes are presented for triaxially braided and three dimensionally woven textile composites. The necessary modeling steps to accommodate these variations are presented with some examples. Some of the ramifications of not accounting for these discrepencies are also addressed.

1-(Hydroxy­meth­yl)pyrene

PubMed Central

Gruber, Tobias; Seichter, Wilhelm; Weber, Edwin

2010-01-01

The asymmetric unit of the title compound, C17H12O, contains two molecules, in which the fused aromatic ring systems are almost planar [maximum deviations = 0.0529 (9) and 0.0256 (9) Å]. In the crystal, aromatic π–π stacking inter­actions (perpendicular distance of centroids of about 3.4 Å) and strong O—H⋯O hydrogen bonds result in a helical arrangement of pyrenyl dimers. PMID:21579858

Hole doping, hybridization gaps, and electronic correlation in graphene on a platinum substrate

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

Hwang, Jinwoong; Hwang, Hwihyeon; Kim, Min-Jeong

The interaction between graphene and substrates provides a viable route to enhance the functionality of both materials. Depending on the nature of electronic interaction at the interface, the electron band structure of graphene is strongly influenced, allowing us to make use of the intrinsic properties of graphene or to design additional functionalities in graphene. In this paper, we present an angle-resolved photoemission study on the interaction between graphene and a platinum substrate. The formation of an interface between graphene and platinum leads to a strong deviation in the electronic structure of graphene not only from its freestanding form but alsomore » from the behavior observed on typical metals. Finally, the combined study on the experimental and theoretical electron band structure unveils the unique electronic properties of graphene on a platinum substrate, which singles out graphene/platinum as a model system investigating graphene on a metallic substrate with strong interaction.« less

Hole doping, hybridization gaps, and electronic correlation in graphene on a platinum substrate

DOE PAGES

Hwang, Jinwoong; Hwang, Hwihyeon; Kim, Min-Jeong; ...

2017-08-02

The interaction between graphene and substrates provides a viable route to enhance the functionality of both materials. Depending on the nature of electronic interaction at the interface, the electron band structure of graphene is strongly influenced, allowing us to make use of the intrinsic properties of graphene or to design additional functionalities in graphene. In this paper, we present an angle-resolved photoemission study on the interaction between graphene and a platinum substrate. The formation of an interface between graphene and platinum leads to a strong deviation in the electronic structure of graphene not only from its freestanding form but alsomore » from the behavior observed on typical metals. Finally, the combined study on the experimental and theoretical electron band structure unveils the unique electronic properties of graphene on a platinum substrate, which singles out graphene/platinum as a model system investigating graphene on a metallic substrate with strong interaction.« less

A Numerical Model Study of Nocturnal Drainage Flows with Strong Wind and Temperature Gradients.

NASA Astrophysics Data System (ADS)

Yamada, T.; Bunker, S.

1989-07-01

A second-moment turbulence-closure model described in Yamada and Bunker is used to simulate nocturnal drainage flows observed during the 1984 ASCOT field expedition in Brush Creek, Colorado. In order to simulate the observed strong wind directional shear and temperature gradients, two modifications are added to the model. The strong wind directional shear was maintained by introducing a `nudging' term in the equation of motion to guide the modeled winds in the layers above the ridge top toward the observed wind direction. The second modification was accomplished by reformulating the conservation equation for the potential temperature in such a way that only the deviation from the horizontally averaged value was prognostically computed.The vegetation distribution used in this study is undoubtedly crude. Nevertheless, the present simulation suggests that tall tree canopy can play an important role in producing inhomogeneous wind distribution, particularly in the levels below the canopy top.

Field emission from carbon nanotube fibers in varying anode-cathode gap with the consideration of contact resistance

NASA Astrophysics Data System (ADS)

Zhang, Peng; Fairchild, S. B.; Back, T. C.; Luo, Yi

2017-12-01

This paper studies field emission (FE) from a single carbon nanotube (CNT) fiber with different anode-cathode (AK) gap distances. It is found that the field enhancement factor depends strongly on the finite AK gap distance, due to the combination of geometrical effects and possible fiber morphology change. The geometrical effects of AK gap distance on the field enhancement factor are confirmed using COMSOL simulations. The slope drop in the Fowler-Northeim (FN) plot of the FE data in the high voltage is related to the electrical contact resistance between the CNT fiber and the substrate. It is found that even a small series resistance to the field emitter (<30% of the emission gap impedance) can strongly modify the FE characteristics in the high voltage regime, inducing a strong deviation from the linear FN plot.

What Children Recall about a Repeated Event When One Instance Is Different from the Others

ERIC Educational Resources Information Center

Connolly, Deborah A.; Gordon, Heidi M.; Woiwod, Dayna M.; Price, Heather L.

2016-01-01

This research examined whether a memorable and unexpected change (deviation details) presented during 1 instance of a repeated event facilitated children's memory for that instance and whether a repeated event facilitated children's memory for deviation details. In Experiments 1 and 2, 8-year-olds (N = 167) watched 1 or 4 live magic shows.…

On the Linear Relation between the Mean and the Standard Deviation of a Response Time Distribution

ERIC Educational Resources Information Center

Wagenmakers, Eric-Jan; Brown, Scott

2007-01-01

Although it is generally accepted that the spread of a response time (RT) distribution increases with the mean, the precise nature of this relation remains relatively unexplored. The authors show that in several descriptive RT distributions, the standard deviation increases linearly with the mean. Results from a wide range of tasks from different…

Effect of ripples on the finite temperature elastic properties of hexagonal boron nitride using strain-fluctuation method

NASA Astrophysics Data System (ADS)

Thomas, Siby; Ajith, K. M.; Valsakumar, M. C.

2017-11-01

This work intents to put forth the results of a classical molecular dynamics study to investigate the temperature dependent elastic constants of monolayer hexagonal boron nitride (h-BN) between 100 and 1000 K for the first time using strain fluctuation method. The temperature dependence of out-of-plane fluctuations (ripples) is quantified and is explained using continuum theory of membranes. At low temperatures, negative in-plane thermal expansion is observed and at high temperatures, a transition to positive thermal expansion has been observed due to the presence of thermally excited ripples. The decrease of Young's modulus, bulk modulus, shear modulus and Poisson's ratio with increase in temperature has been analyzed. The thermal rippling in h-BN leads to strong anharmonic behaviour that causes large deviation from the isotropic elasticity. A detailed study shows that the strong thermal rippling in large systems is also responsible for the softening of elastic constants in h-BN. From the determined values of elastic constants and elastic moduli, it has been elucidated that 2D h-BN sheets meet the Born's mechanical stability criterion in the investigated temperature range. The variation of longitudinal and shear velocities with temperature is also calculated from the computed values of elastic constants and elastic moduli.

Shear viscosity of a hadron gas and influence of resonance lifetimes on relaxation time

NASA Astrophysics Data System (ADS)

Rose, J.-B.; Torres-Rincon, J. M.; Schäfer, A.; Oliinychenko, D. R.; Petersen, H.

2018-05-01

We address a discrepancy between different computations of η /s (shear viscosity over entropy density) of hadronic matter. Substantial deviations of this coefficient are found between transport approaches mainly based on resonance propagation with finite lifetime and other (semianalytical) approaches with energy-dependent cross sections, where interactions do not introduce a timescale. We provide an independent extraction of this coefficient by using the newly developed SMASH (Simulating Many Accelerated Strongly interacting Hadrons) transport code, which is an example of a mainly resonance-based approach. We compare the results from SMASH with numerical solutions of the Boltzmann equation for simple systems using the Chapman-Enskog expansion, as well as previous results in the literature. Our conclusion is that the hadron interaction via resonance formation/decay strongly affects the transport properties of the system, resulting in significant differences in η /s with respect to other approaches where binary collisions dominate. We argue that the relaxation time of the system—which characterizes the shear viscosity—is determined by the interplay between the mean free time and the lifetime of resonances. We show how an artificial shortening of the resonance lifetimes, or the addition of a background elastic cross section nicely interpolate between the two discrepant results.

CALCULATED REGENERATOR PERFORMANCE AT 4 K WITH HELIUM-4 AND HELIUM-3

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

Radebaugh, Ray; Huang Yonghua; O'Gallagher, Agnes

2008-03-16

The helium-4 working fluid in regenerative cryocoolers operating with the cold end near 4 K deviates considerably from an ideal gas. As a result, losses in the regenerator, given by the time-averaged enthalpy flux, are increased and are strong functions of the operating pressure and temperature. Helium-3, with its lower boiling point, behaves somewhat closer to an ideal gas in this low temperature range and can reduce the losses in 4 K regenerators. An analytical model is used to find the fluid properties that strongly influence the regenerator losses as well as the gross refrigeration power. The thermodynamic and transportmore » properties of helium-3 were incorporated into the latest NIST regenerator numerical model, known as REGEN3.3, which was used to model regenerator performance with either helium-4 or helium-3. With this model we show how the use of helium-3 in place of helium-4 can improve the performance of 4 K regenerative cryocoolers. The effects of operating pressure, warm-end temperature, and frequency on regenerators with helium-4 and helium-3 are investigated and compared. The results are used to find optimum operating conditions. The frequency range investigated varies from 1 Hz to 30 Hz, with particular emphasis on higher frequencies.« less

Controlling entangled spin-orbit coupling of 5 d states with interfacial heterostructure engineering

DOE PAGES

Kim, J. -W.; Choi, Y.; Chun, S. H.; ...

2018-03-26

Here, the combination of strong electron correlations in 3d transition metal oxides and spin-orbit interactions in the 5d counterpart can give rise to exotic electronic and magnetic properties. Here, the nature of emerging phenomena at the interface between SrIrO 3 (SIO) and La 2/3Sr 1/3MnO 3 (LSMO) is presented. Nominally, SIO with strong spin-orbit interaction is metallic and nonmagnetic on the verge of a metal-insulator transition, whereas LSMO is metallic and ferromagnetic with itinerant character and high spin polarization. In the 1:1 LSMO/SIO superlattice, we observe ferromagnetic Mn moments with an insulating behavior, accompanied by antiferromagnetic ordering in SIO. Element-resolvedmore » x-ray magnetic circular dichroism proves that there is a weak net ferromagnetic Ir moment aligned antiparallel to the Mn counterpart. The branching ratio shows the formation of molecular-orbitals between the Mn and Ir layers modifying the Ir 5d electronic configuration through the mixture of t 2g and e g states, resulting in a deviation from J eff = ½. This result demonstrates a pathway to manipulate the spin-orbit entanglement in 5d states with 2-dimensional 3d spin-polarized electrons through heterostructure design.« less

Controlling entangled spin-orbit coupling of 5 d states with interfacial heterostructure engineering

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

Kim, J. -W.; Choi, Y.; Chun, S. H.

Here, the combination of strong electron correlations in 3d transition metal oxides and spin-orbit interactions in the 5d counterpart can give rise to exotic electronic and magnetic properties. Here, the nature of emerging phenomena at the interface between SrIrO 3 (SIO) and La 2/3Sr 1/3MnO 3 (LSMO) is presented. Nominally, SIO with strong spin-orbit interaction is metallic and nonmagnetic on the verge of a metal-insulator transition, whereas LSMO is metallic and ferromagnetic with itinerant character and high spin polarization. In the 1:1 LSMO/SIO superlattice, we observe ferromagnetic Mn moments with an insulating behavior, accompanied by antiferromagnetic ordering in SIO. Element-resolvedmore » x-ray magnetic circular dichroism proves that there is a weak net ferromagnetic Ir moment aligned antiparallel to the Mn counterpart. The branching ratio shows the formation of molecular-orbitals between the Mn and Ir layers modifying the Ir 5d electronic configuration through the mixture of t 2g and e g states, resulting in a deviation from J eff = ½. This result demonstrates a pathway to manipulate the spin-orbit entanglement in 5d states with 2-dimensional 3d spin-polarized electrons through heterostructure design.« less

Development of a sensitive passive sampler using indigotrisulfonate for the determination of tropospheric ozone.

PubMed

Garcia, Gabriel; Allen, Andrew George; Cardoso, Arnaldo Alves

2010-06-01

A new sampling and analytical design for measurement of ambient ozone is presented. The procedure is based on ozone absorption and decoloration (at 600 nm) of indigotrisulfonate dye, where ozone adds itself across the carbon-carbon double bond of the indigo. A mean relative standard deviation of 8.6% was obtained using samplers exposed in triplicate, and a correlation coefficient (r) of 0.957 was achieved in parallel measurements using the samplers and a commercial UV ozone instrument. The devices were evaluated in a measurement campaign, mapping spatial and temporal trends of ozone concentrations in a region of southeast Brazil strongly influenced by seasonal agricultural biomass burning, with associated emissions of ozone precursors. Ozone concentrations were highest in rural areas and lowest at an urban site, due to formation during downwind transport and short-term depletion due to titration with nitric oxide. Ozone concentrations showed strong seasonal trends, due to the influences of precursor emissions, relative humidity and solar radiation intensity. Advantages of the technique include ease and speed of use, the ready availability of components, and excellent sensitivity. Achievable temporal resolution of ozone concentrations is 8 hours at an ambient ozone concentration of 3.8 ppb, or 2 hours at a concentration of 15.2 ppb.

Recent progress towards a quantitative description of filamentary SOL transport

NASA Astrophysics Data System (ADS)

Carralero, D.; Siccinio, M.; Komm, M.; Artene, S. A.; D'Isa, F. A.; Adamek, J.; Aho-Mantila, L.; Birkenmeier, G.; Brix, M.; Fuchert, G.; Groth, M.; Lunt, T.; Manz, P.; Madsen, J.; Marsen, S.; Müller, H. W.; Stroth, U.; Sun, H. J.; Vianello, N.; Wischmeier, M.; Wolfrum, E.; ASDEX Upgrade Team; COMPASS Team; Contributors, JET; The EUROfusion MST Team

2017-05-01

A summary of recent results on filamentary transport, mostly obtained with the ASDEX-Upgrade tokamak (AUG), is presented and discussed in an attempt to produce a coherent picture of scrape-off layer (SOL) filamentary transport. A clear correlation is found between L-mode density shoulder formation in the outer midplane and a transition between the sheath-limited and the inertial filamentary regimes. Divertor collisionality is found to be the parameter triggering the transition. A clear reduction of the ion temperature takes place in the far SOL after the transition, both for the background and the filaments. This coincides with a strong variation of the ion temperature distribution, which deviates from Gaussianity and becomes dominated by a strong peak below 5 eV. The filament transition mechanism triggered by a critical value of collisionality seems to be generally applicable to inter-ELM H-mode plasmas, although a secondary threshold related to deuterium fueling is observed. EMC3-EIRENE simulations of neutral dynamics show that an ionization front near the main chamber wall is formed after the shoulder formation. Finally, a clear increase of SOL opacity to neutrals is observed, associated with the shoulder formation. A common SOL transport framework is proposed to account for all these results, and their potential implications for future generation devices are discussed.

Triassic–Jurassic climate in continental high-latitude Asia was dominated by obliquity-paced variations (Junggar Basin, Ürümqi, China)

PubMed Central

Sha, Jingeng; Olsen, Paul E.; Pan, Yanhong; Xu, Daoyi; Wang, Yaqiang; Zhang, Xiaolin; Yao, Xiaogang; Vajda, Vivi

2015-01-01

Empirical constraints on orbital gravitational solutions for the Solar System can be derived from the Earth’s geological record of past climates. Lithologically based paleoclimate data from the thick, coal-bearing, fluvial-lacustrine sequences of the Junggar Basin of Northwestern China (paleolatitude ∼60°) show that climate variability of the warm and glacier-free high latitudes of the latest Triassic–Early Jurassic (∼198–202 Ma) Pangea was strongly paced by obliquity-dominated (∼40 ky) orbital cyclicity, based on an age model using the 405-ky cycle of eccentricity. In contrast, coeval low-latitude continental climate was much more strongly paced by climatic precession, with virtually no hint of obliquity. Although this previously unknown obliquity dominance at high latitude is not necessarily unexpected in a high CO2 world, these data deviate substantially from published orbital solutions in period and amplitude for eccentricity cycles greater than 405 ky, consistent with chaotic diffusion of the Solar System. In contrast, there are indications that the Earth–Mars orbital resonance was in today’s 2-to-1 ratio of eccentricity to inclination. These empirical data underscore the need for temporally comprehensive, highly reliable data, as well as new gravitational solutions fitting those data. PMID:25759439

Triassic-Jurassic climate in continental high-latitude Asia was dominated by obliquity-paced variations (Junggar Basin, Ürümqi, China).

PubMed

Sha, Jingeng; Olsen, Paul E; Pan, Yanhong; Xu, Daoyi; Wang, Yaqiang; Zhang, Xiaolin; Yao, Xiaogang; Vajda, Vivi

2015-03-24

Empirical constraints on orbital gravitational solutions for the Solar System can be derived from the Earth's geological record of past climates. Lithologically based paleoclimate data from the thick, coal-bearing, fluvial-lacustrine sequences of the Junggar Basin of Northwestern China (paleolatitude ∼60°) show that climate variability of the warm and glacier-free high latitudes of the latest Triassic-Early Jurassic (∼198-202 Ma) Pangea was strongly paced by obliquity-dominated (∼40 ky) orbital cyclicity, based on an age model using the 405-ky cycle of eccentricity. In contrast, coeval low-latitude continental climate was much more strongly paced by climatic precession, with virtually no hint of obliquity. Although this previously unknown obliquity dominance at high latitude is not necessarily unexpected in a high CO2 world, these data deviate substantially from published orbital solutions in period and amplitude for eccentricity cycles greater than 405 ky, consistent with chaotic diffusion of the Solar System. In contrast, there are indications that the Earth-Mars orbital resonance was in today's 2-to-1 ratio of eccentricity to inclination. These empirical data underscore the need for temporally comprehensive, highly reliable data, as well as new gravitational solutions fitting those data.

Vertical dependence of black carbon, sulphate and biomass burning aerosol radiative forcing

NASA Astrophysics Data System (ADS)

Samset, Bjørn H.; Myhre, Gunnar

2011-12-01

A global radiative transfer model is used to calculate the vertical profile of shortwave radiative forcing from a prescribed amount of aerosols. We study black carbon (BC), sulphate (SO4) and a black and organic carbon mixture typical of biomass burning (BIO), by prescribing aerosol burdens in layers between 1000 hPa and 20 hPa and calculating the resulting direct radiative forcing divided by the burden (NDRF). We find a strong sensitivity in the NDRF for BC with altitude, with a tenfold increase between BC close to the surface and the lower part of the stratosphere. Clouds are a major contributor to this dependence with altitude, but other factors also contribute. We break down and explain the different physical contributors to this strong sensitivity. The results show a modest regional dependence of the altitudinal dependence of BC NDRF between industrial regions, while for regions with properties deviating from the global mean NDRF variability is significant. Variations due to seasons and interannual changes in cloud conditions are found to be small. We explore the effect that large altitudinal variation in NDRF may have on model estimates of BC radiative forcing when vertical aerosol distributions are insufficiently constrained, and discuss possible applications of the present results for reducing inter-model differences.

Controlling entangled spin-orbit coupling of 5 d states with interfacial heterostructure engineering

NASA Astrophysics Data System (ADS)

Kim, J.-W.; Choi, Y.; Chun, S. H.; Haskel, D.; Yi, D.; Ramesh, R.; Liu, J.; Ryan, P. J.

2018-03-01

The combination of strong electron correlations in 3 d transition-metal oxides and spin-orbit interactions in the 5 d counterpart can give rise to exotic electronic and magnetic properties. Here, the nature of emerging phenomena at the interface between SrIr O3 (SIO) and L a2 /3S r1 /3Mn O3 (LSMO) is presented. Nominally, SIO with strong spin-orbit interaction is metallic and nonmagnetic on the verge of a metal-insulator transition, whereas LSMO is metallic and ferromagnetic with itinerant character and high spin polarization. In the 1:1 LSMO/SIO superlattice, we observe ferromagnetic Mn moments with an insulating behavior, accompanied by antiferromagnetic ordering in SIO. Element-resolved x-ray magnetic circular dichroism proves that there is a weak net ferromagnetic Ir moment aligned antiparallel to the Mn counterpart. The branching ratio shows the formation of molecular orbitals between the Mn and Ir layers modifying the Ir 5 d electronic configuration through the mixture of t2 g and eg states, resulting in a deviation from Jeff=1 /2 . This result demonstrates a pathway to manipulate the spin-orbit entanglement in 5 d states with two-dimensional 3 d spin-polarized electrons through heterostructure design.

Inter-technique validation of tropospheric slant total delays

NASA Astrophysics Data System (ADS)

Kačmařík, Michal; Douša, Jan; Dick, Galina; Zus, Florian; Brenot, Hugues; Möller, Gregor; Pottiaux, Eric; Kapłon, Jan; Hordyniec, Paweł; Václavovic, Pavel; Morel, Laurent

2017-06-01

An extensive validation of line-of-sight tropospheric slant total delays (STD) from Global Navigation Satellite Systems (GNSS), ray tracing in numerical weather prediction model (NWM) fields and microwave water vapour radiometer (WVR) is presented. Ten GNSS reference stations, including collocated sites, and almost 2 months of data from 2013, including severe weather events were used for comparison. Seven institutions delivered their STDs based on GNSS observations processed using 5 software programs and 11 strategies enabling to compare rather different solutions and to assess the impact of several aspects of the processing strategy. STDs from NWM ray tracing came from three institutions using three different NWMs and ray-tracing software. Inter-techniques evaluations demonstrated a good mutual agreement of various GNSS STD solutions compared to NWM and WVR STDs. The mean bias among GNSS solutions not considering post-fit residuals in STDs was -0.6 mm for STDs scaled in the zenith direction and the mean standard deviation was 3.7 mm. Standard deviations of comparisons between GNSS and NWM ray-tracing solutions were typically 10 mm ± 2 mm (scaled in the zenith direction), depending on the NWM model and the GNSS station. Comparing GNSS versus WVR STDs reached standard deviations of 12 mm ± 2 mm also scaled in the zenith direction. Impacts of raw GNSS post-fit residuals and cleaned residuals on optimal reconstructing of GNSS STDs were evaluated at inter-technique comparison and for GNSS at collocated sites. The use of raw post-fit residuals is not generally recommended as they might contain strong systematic effects, as demonstrated in the case of station LDB0. Simplified STDs reconstructed only from estimated GNSS tropospheric parameters, i.e. without applying post-fit residuals, performed the best in all the comparisons; however, it obviously missed part of tropospheric signals due to non-linear temporal and spatial variations in the troposphere. Although the post-fit residuals cleaned of visible systematic errors generally showed a slightly worse performance, they contained significant tropospheric signal on top of the simplified model. They are thus recommended for the reconstruction of STDs, particularly during high variability in the troposphere. Cleaned residuals also showed a stable performance during ordinary days while containing promising information about the troposphere at low-elevation angles.

Blood pressure variability in man: its relation to high blood pressure, age and baroreflex sensitivity.

PubMed

Mancia, G; Ferrari, A; Gregorini, L; Parati, G; Pomidossi, G; Bertinieri, G; Grassi, G; Zanchetti, A

1980-12-01

1. Intra-arterial blood pressure and heart rate were recorded for 24 h in ambulant hospitalized patients of variable age who had normal blood pressure or essential hypertension. Mean 24 h values, standard deviations and variation coefficient were obtained as the averages of values separately analysed for 48 consecutive half-hour periods. 2. In older subjects standard deviation and variation coefficient for mean arterial pressure were greater than in younger subjects with similar pressure values, whereas standard deviation and variation coefficient for mean arterial pressure were greater than in younger subjects with similar pressure values, whereas standard deviation aations and variation coefficient were obtained as the averages of values separately analysed for 48 consecurive half-hour periods. 2. In older subjects standard deviation and variation coefficient for mean arterial pressure were greater than in younger subjects with similar pressure values, whereas standard deviation and variation coefficient for heart rate were smaller. 3. In hypertensive subjects standard deviation for mean arterial pressure was greater than in normotensive subjects of similar ages, but this was not the case for variation coefficient, which was slightly smaller in the former than in the latter group. Normotensive and hypertensive subjects showed no difference in standard deviation and variation coefficient for heart rate. 4. In both normotensive and hypertensive subjects standard deviation and even more so variation coefficient were slightly or not related to arterial baroreflex sensitivity as measured by various methods (phenylephrine, neck suction etc.). 5. It is concluded that blood pressure variability increases and heart rate variability decreases with age, but that changes in variability are not so obvious in hypertension. Also, differences in variability among subjects are only marginally explained by differences in baroreflex function.

A Modified Differential Coherent Bit Synchronization Algorithm for BeiDou Weak Signals with Large Frequency Deviation.

PubMed

Han, Zhifeng; Liu, Jianye; Li, Rongbing; Zeng, Qinghua; Wang, Yi

2017-07-04

BeiDou system navigation messages are modulated with a secondary NH (Neumann-Hoffman) code of 1 kbps, where frequent bit transitions limit the coherent integration time to 1 millisecond. Therefore, a bit synchronization algorithm is necessary to obtain bit edges and NH code phases. In order to realize bit synchronization for BeiDou weak signals with large frequency deviation, a bit synchronization algorithm based on differential coherent and maximum likelihood is proposed. Firstly, a differential coherent approach is used to remove the effect of frequency deviation, and the differential delay time is set to be a multiple of bit cycle to remove the influence of NH code. Secondly, the maximum likelihood function detection is used to improve the detection probability of weak signals. Finally, Monte Carlo simulations are conducted to analyze the detection performance of the proposed algorithm compared with a traditional algorithm under the CN0s of 20~40 dB-Hz and different frequency deviations. The results show that the proposed algorithm outperforms the traditional method with a frequency deviation of 50 Hz. This algorithm can remove the effect of BeiDou NH code effectively and weaken the influence of frequency deviation. To confirm the feasibility of the proposed algorithm, real data tests are conducted. The proposed algorithm is suitable for BeiDou weak signal bit synchronization with large frequency deviation.

ERP correlates of unexpected word forms in a picture–word study of infants and adults

PubMed Central

Duta, M.D.; Styles, S.J.; Plunkett, K.

2012-01-01

We tested 14-month-olds and adults in an event-related potentials (ERPs) study in which pictures of familiar objects generated expectations about upcoming word forms. Expected word forms labelled the picture (word condition), while unexpected word forms mismatched by either a small deviation in word medial vowel height (mispronunciation condition) or a large deviation from the onset of the first speech segment (pseudoword condition). Both infants and adults showed sensitivity to both types of unexpected word form. Adults showed a chain of discrete effects: positivity over the N1 wave, negativity over the P2 wave (PMN effect) and negativity over the N2 wave (N400 effect). Infants showed a similar pattern, including a robust effect similar to the adult P2 effect. These observations were underpinned by a novel visualisation method which shows the dynamics of the ERP within bands of the scalp over time. The results demonstrate shared processing mechanisms across development, as even subtle deviations from expected word forms were indexed in both age groups by a reduction in the amplitude of characteristic waves in the early auditory evoked potential. PMID:22483072

Characterization and Identification of Productivity-Associated Rhizobacteria in Wheat

PubMed Central

Habiger, Joshua

2012-01-01

The rhizosphere is populated by a numerous and diverse array of rhizobacteria, and many impact productivity in largely unknown ways. Here we characterize the rhizobacterial community in a wheat variety categorized according to shoot biomass using 16S rRNA pyrosequencing abundance data. Plants were grown in homogenized field soil under greenhouse conditions, and DNA was extracted and pyrosequenced, resulting in 29,007 quality sequences. Operational taxonomic units (OTUs) that were significantly associated with biomass productivity were identified using an exact test adjusted for the false-discovery rate. The productivity deviation expressed as a percentage of the total mean square for regression (PMSR) was determined for each OTU. Out of 719 OTUs, 42 showed significant positive associations and 39 showed significant negative associations (q value, ≤0.05). OTUs with the greatest net positive associations, by genus, were as follows: Duganella, OTU 43 and OTU 3; Janthinobacterium, OTU 278; Pseudomonas, OTU 588; and Cellvibrio, OTU 1847. Those with negative associations were as follows: Bacteria, OTU 273; Chryseobacterium, OTU 508; Proteobacteria, OTU 249; and Enterobacter, OTU 357. Shoot biomass productivity was strongly correlated with the balance between the overall abundances of positive- and negative-productivity-associated OTUs. High-productivity rhizospheres contained 9.2 significant positives for every negatively associated rhizobacterium, while low-productivity rhizospheres showed 2.3 significant negatives for every positively associated rhizobacterium. Overall rhizobacterial community diversity as measured by the Chao1, Shannon, and Simpson indexes was nonlinearly related to productivity, closely fitting a wavelike cubic equation. We conclude that shoot biomass productivity is strongly related to the ratio of positive- to negative-productivity-associated rhizobacteria in the rhizosphere. This study identifies significant OTUs composing the productive and unproductive rhizobacterial communities. PMID:22504815

Long term variability of Cygnus X-1. VII. Orbital variability of the focussed wind in Cyg X-1/HDE 226868 system

NASA Astrophysics Data System (ADS)

Grinberg, V.; Leutenegger, M. A.; Hell, N.; Pottschmidt, K.; Böck, M.; García, J. A.; Hanke, M.; Nowak, M. A.; Sundqvist, J. O.; Townsend, R. H. D.; Wilms, J.

2015-04-01

Binary systems with an accreting compact object offer a unique opportunity to investigate the strong, clumpy, line-driven winds of early-type supergiants by using the compact object's X-rays to probe the wind structure. We analyze the two-component wind of HDE 226868, the O9.7Iab giant companion of the black hole Cyg X-1, using 4.77 Ms Rossi X-ray Timing Explorer (RXTE) observations of the system taken over the course of 16 years. Absorption changes strongly over the 5.6 d binary orbit, but also shows a large scatter at a given orbital phase, especially at superior conjunction. The orbital variability is most prominent when the black hole is in the hard X-ray state. Our data are poorer for the intermediate and soft state, but show signs for orbital variability of the absorption column in the intermediate state. We quantitatively compare the data in the hard state to a toy model of a focussed Castor-Abbott-Klein wind: as it does not incorporate clumping, the model does not describe the observations well. A qualitative comparison to a simplified simulation of clumpy winds with spherical clumps shows good agreement in the distribution of the equivalent hydrogen column density for models with a porosity length on the order of the stellar radius at inferior conjunction; we conjecture that the deviations between data and model at superior conjunction could either be due to lack of a focussed wind component in the model or to a more complicated clump structure. Appendix A is available in electronic form at http://www.aanda.org

Long term variability of Cygnus X-1: VII. Orbital variability of the focussed wind in Cyg X-1/HDE 226868 system

DOE PAGES

Grinberg, V.; Leutenegger, M. A.; Hell, N.; ...

2015-04-16

Binary systems with an accreting compact object offer a unique opportunity to investigate the strong, clumpy, line-driven winds of early-type supergiants by using the compact object’s X-rays to probe the wind structure. In this paper, we analyze the two-component wind of HDE 226868, the O9.7Iab giant companion of the black hole Cyg X-1, using 4.77 Ms Rossi X-ray Timing Explorer (RXTE) observations of the system taken over the course of 16 years. Absorption changes strongly over the 5.6 d binary orbit, but also shows a large scatter at a given orbital phase, especially at superior conjunction. The orbital variability ismore » most prominent when the black hole is in the hard X-ray state. Our data are poorer for the intermediate and soft state, but show signs for orbital variability of the absorption column in the intermediate state. We quantitatively compare the data in the hard state to a toy model of a focussed Castor-Abbott-Klein wind: as it does not incorporate clumping, the model does not describe the observations well. Finally, a qualitative comparison to a simplified simulation of clumpy winds with spherical clumps shows good agreement in the distribution of the equivalent hydrogen column density for models with a porosity length on the order of the stellar radius at inferior conjunction; we conjecture that the deviations between data and model at superior conjunction could either be due to lack of a focussed wind component in the model or to a more complicated clump structure.« less

The Evolution of Indian and Pacific Ocean Denitrification and Nitrogen Dynamcs since the Miocene

NASA Astrophysics Data System (ADS)

Ravelo, A. C.; Carney, C.; Rosenthal, Y.; Holbourn, A.; Kulhanek, D. K.

2017-12-01

The feedbacks between geochemical cycles and physical climate change are poorly understood; however, there has been tremendous progress in developing coupled models to help predict the direction and strength of these feedbacks. As such, there is a need for more data to validate and test these models. To this end, the nitrogen (N) cycle, and its links to the biological pump and to climate, is an active area of paleoceanographic research. Using N isotope records, Robinson et al. (2014) showed that pelagic denitrification in the Indian and Pacific Oceans intensified as climate cooled and subsurface ventilation decreased since the Pliocene. They pointed out that a more ventilated warm Pliocene contrasts with glacial-interglacial patterns wherein more ventilation occurs during cold phases, indicating that different mechanisms may occur at different timescales. Our objective is to better understand the nature of the feedbacks between the oceanic N cycle and climate by focusing on the large dynamic range of conditions that occurred during and since the Miocene. We used new cores drilled during IODP Expedition 363 to generate bulk sediment N isotope records at three western tropical Pacific sites (U1486, U1488, U1490) and one southeastern tropical Indian Ocean site (U1482). We find that the N isotope trends since the Pliocene are in agreement with previous studies showing increasing denitrification as climate cooled. In the Miocene, the Indian Ocean record shows no long-term N isotope trend whereas the Pacific Ocean records show a trend that is roughly coupled to changes in global climate suggesting that pelagic denitrification in the Pacific was strongly influenced by greater ventilation during global warmth. However, there are notable deviations from this coupling during several intervals in the Miocene, and there are site-to-site differences in trends. These deviations and differences can be explained by changes in tropical productivity (e.g., late Miocene biogenic bloom), which drove changes subsurface oxygenation and denitrification, and by changes in regional circulation. Our study provides fundamental data that can be used to validate conceptual and numerical models of the long-term coupling of climate, biological productivity and ocean chemistry.

Deviations of Mesial Root Canals of Mandibular First Molar Teeth at the Apical Third: A Micro-computed Tomographic Study.

PubMed

Keles, Ali; Keskin, Cangül

2018-06-01

The present study aimed to quantitatively analyze apical foramen deviations of mesial root canals of mandibular first molar teeth by means of micro-computed tomographic (micro-CT) imaging. Micro-CT images of the mesial roots of 109 mandibular first molar teeth with independent mesiobuccal (MB) and mesiolingual (ML) root canals were analyzed. The deviations of the apical foramina of the MB, ML, and middle mesial root canals from the anatomic apex were measured. The vertical distance between the apical foramina of each mesial root canal in relation to each other was also calculated. The distances from the apical foramina of the MB, ML, and middle mesial root canals to the anatomic apex of the mesial root were up to 2.51 mm, 3.21 mm, and 5.67 mm, respectively. There was no significant difference between the deviations of MB and ML root canals from each other (P > .05). The middle mesial root canal showed the greatest deviation compared with the MB and ML canals (P < .05). The apical foramina of mesial root canals of mandibular first molar teeth showed greater variations from each other and anatomic apices than previously reported. Clinically, the use of electronic apex locators for the detection of minor apical foramen of each mesial root canal is of the utmost important. Copyright © 2018 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Combining retinal nerve fiber layer thickness with individual retinal blood vessel locations allows modeling of central vision loss in glaucoma

NASA Astrophysics Data System (ADS)

Wang, Hui; Wang, Mengyu; Baniasadi, Neda; Jin, Qingying; Elze, Tobias

2017-02-01

Purpose: To assess whether modeling of central vision loss (CVL) due to glaucoma by optical coherence tomography (OCT) retinal nerve fiber (RNF) layer thickness (RNFLT) can be improved by including the location of the major inferior temporal retinal artery (ITA), a known correlate of individual RNF geometry. Methods: Pat- tern deviations of the two locations of the Humphrey 24-2 visual field (VF) known to be specifically vulnerable to glaucomatous CVL and OCT RNFLT on the corresponding circumpapillary sector around the optic nerve head within the radius of 1.73mm were retrospectively selected from 428 eyes of 428 patients of a large clinical glaucoma service. ITA was marked on the 1.73mm circle by a trained observer. Linear regression models were fitted with CVL as dependent variable and VF mean deviation (MD) plus either of (1) RNFLT, (2) ITA, and (3) their combination, respectively, as regressors. To assess CVL over all levels of glaucoma severity, the three models were compared to a null model containing only MD. A Baysian model comparison was performed with the Bayes Factor (BF) as measure of strength of evidence (BF<3: no evidence, 3-20: positive evidence, >20: strong evidence over null model). Results: Neither RNFLT (BF=0.9) nor ITA (BF=1.4) alone provided positive evidence over the null model, but their combination resulted in a model with strong evidence (BF=21.4). Conclusion: While the established circumpapillary RNFLT sector, based on population statistics, could not satisfactorily model CVL, the inclusion of a retinal parameter related to individual eye anatomy yielded a strong structure-function model.

Probing the distance-duality relation with high- z data

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

Holanda, R.F.L.; Busti, V.C.; Lima, F.S.

2017-09-01

Measurements of strong gravitational lensing jointly with type Ia supernovae (SNe Ia) observations have been used to test the validity of the cosmic distance duality relation (CDDR), D{sub L}( z )/[(1+ z ){sup 2D{sub A}}( z )]=η=1, where D{sub L}(z) and D{sub A}(z) are the luminosity and the angular diameter distances to a given redshift z , respectively. However, several lensing systems lie in the interval 1.4 ≤ z ≤ 3.6 i.e., beyond the redshift range of current SNe Ia compilations ( z ≈ 1.50), which prevents this kind of test to be fully explored. In this paper, we circumventmore » this problem by testing the CDDR considering observations of strong gravitational lensing along with SNe Ia and (a subsample from) the latest gamma-ray burst distance modulus data, whose redshift range is 0.033 ≤ z ≤ 9.3. We parameterize their luminosity distances with a second degree polynomial function and search for possible deviations from the CDDR validity by using four different η( z ) functions: η( z )=1+η{sub 0z}, η( z )=1+η{sub 0z}/(1+ z ), η( z )=(1+ z ){sup η{sub 0}} and η( z )=1+η{sub 0ln}(1+ z ). Unlike previous tests done at redshifts lower than 1.50, the likelihood for η{sub 0} depends strongly on the η( z ) function considered, but we find no significant deviation from the CDDR validity (η{sub 0}=0). However, our analyses also point to the fact that caution is needed when one fits data in higher redshifts to test the CDDR as well as a better understanding of the mass distribution of lenses also is required for more accurate results.« less

Stable clustering and the resolution of dissipationless cosmological N-body simulations

NASA Astrophysics Data System (ADS)

Benhaiem, David; Joyce, Michael; Sylos Labini, Francesco

2017-10-01

The determination of the resolution of cosmological N-body simulations, I.e. the range of scales in which quantities measured in them represent accurately the continuum limit, is an important open question. We address it here using scale-free models, for which self-similarity provides a powerful tool to control resolution. Such models also provide a robust testing ground for the so-called stable clustering approximation, which gives simple predictions for them. Studying large N-body simulations of such models with different force smoothing, we find that these two issues are in fact very closely related: our conclusion is that the accuracy of two-point statistics in the non-linear regime starts to degrade strongly around the scale at which their behaviour deviates from that predicted by the stable clustering hypothesis. Physically the association of the two scales is in fact simple to understand: stable clustering fails to be a good approximation when there are strong interactions of structures (in particular merging) and it is precisely such non-linear processes which are sensitive to fluctuations at the smaller scales affected by discretization. Resolution may be further degraded if the short distance gravitational smoothing scale is larger than the scale to which stable clustering can propagate. We examine in detail the very different conclusions of studies by Smith et al. and Widrow et al. and find that the strong deviations from stable clustering reported by these works are the results of over-optimistic assumptions about scales resolved accurately by the measured power spectra, and the reliance on Fourier space analysis. We emphasize the much poorer resolution obtained with the power spectrum compared to the two-point correlation function.

Accuracy comparison of guided surgery for dental implants according to the tissue of support: a systematic review and meta-analysis.

PubMed

Raico Gallardo, Yolanda Natali; da Silva-Olivio, Isabela Rodrigues Teixeira; Mukai, Eduardo; Morimoto, Susana; Sesma, Newton; Cordaro, Luca

2017-05-01

To systematically assess the current dental literature comparing the accuracy of computer-aided implant surgery when using different supporting tissues (tooth, mucosa, or bone). Two reviewers searched PubMed (1972 to January 2015) and the Cochrane Central Register of Controlled Trials (Central) (2002 to January 2015). For the assessment of accuracy, studies were included with the following outcome measures: (i) angle deviation, (ii) deviation at the entry point, and (iii) deviation at the apex. Eight clinical studies from the 1602 articles initially identified met the inclusion criteria for the qualitative analysis. Four studies (n = 599 implants) were evaluated using meta-analysis. The bone-supported guides showed a statistically significant greater deviation in angle (P < 0.001), entry point (P = 0.01), and the apex (P = 0.001) when compared to the tooth-supported guides. Conversely, when only retrospective studies were analyzed, not significant differences are revealed in the deviation of the entry point and apex. The mucosa-supported guides indicated a statistically significant greater reduction in angle deviation (P = 0.02), deviation at the entry point (P = 0.002), and deviation at the apex (P = 0.04) when compared to the bone-supported guides. Between the mucosa- and tooth-supported guides, there were no statistically significant differences for any of the outcome measures. It can be concluded that the tissue of the guide support influences the accuracy of computer-aided implant surgery. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Generalized Cahn-Hilliard equation for solutions with drastically different diffusion coefficients. Application to exsolution in ternary feldspar

NASA Astrophysics Data System (ADS)

Petrishcheva, E.; Abart, R.

2012-04-01

We address mathematical modeling and computer simulations of phase decomposition in a multicomponent system. As opposed to binary alloys with one common diffusion parameter, our main concern is phase decomposition in real geological systems under influence of strongly different interdiffusion coefficients, as it is frequently encountered in mineral solid solutions with coupled diffusion on different sub-lattices. Our goal is to explain deviations from equilibrium element partitioning which are often observed in nature, e.g., in a cooled ternary feldspar. To this end we first adopt the standard Cahn-Hilliard model to the multicomponent diffusion problem and account for arbitrary diffusion coefficients. This is done by using Onsager's approach such that flux of each component results from the combined action of chemical potentials of all components. In a second step the generalized Cahn-Hilliard equation is solved numerically using finite-elements approach. We introduce and investigate several decomposition scenarios that may produce systematic deviations from the equilibrium element partitioning. Both ideal solutions and ternary feldspar are considered. Typically, the slowest component is initially "frozen" and the decomposition effectively takes place only for two "fast" components. At this stage the deviations from the equilibrium element partitioning are indeed observed. These deviations may became "frozen" under conditions of cooling. The final equilibration of the system occurs on a considerably slower time scale. Therefore the system may indeed remain unaccomplished at the observation point. Our approach reveals the intrinsic reasons for the specific phase separation path and rigorously describes it by direct numerical solution of the generalized Cahn-Hilliard equation.

Welding deviation detection algorithm based on extremum of molten pool image contour

NASA Astrophysics Data System (ADS)

Zou, Yong; Jiang, Lipei; Li, Yunhua; Xue, Long; Huang, Junfen; Huang, Jiqiang

2016-01-01

The welding deviation detection is the basis of robotic tracking welding, but the on-line real-time measurement of welding deviation is still not well solved by the existing methods. There is plenty of information in the gas metal arc welding(GMAW) molten pool images that is very important for the control of welding seam tracking. The physical meaning for the curvature extremum of molten pool contour is revealed by researching the molten pool images, that is, the deviation information points of welding wire center and the molten tip center are the maxima and the local maxima of the contour curvature, and the horizontal welding deviation is the position difference of these two extremum points. A new method of weld deviation detection is presented, including the process of preprocessing molten pool images, extracting and segmenting the contours, obtaining the contour extremum points, and calculating the welding deviation, etc. Extracting the contours is the premise, segmenting the contour lines is the foundation, and obtaining the contour extremum points is the key. The contour images can be extracted with the method of discrete dyadic wavelet transform, which is divided into two sub contours including welding wire and molten tip separately. The curvature value of each point of the two sub contour lines is calculated based on the approximate curvature formula of multi-points for plane curve, and the two points of the curvature extremum are the characteristics needed for the welding deviation calculation. The results of the tests and analyses show that the maximum error of the obtained on-line welding deviation is 2 pixels(0.16 mm), and the algorithm is stable enough to meet the requirements of the pipeline in real-time control at a speed of less than 500 mm/min. The method can be applied to the on-line automatic welding deviation detection.

Negative thermal expansion and magnetoelastic coupling in the breathing pyrochlore lattice material LiGaCr4S8

NASA Astrophysics Data System (ADS)

Pokharel, G.; May, A. F.; Parker, D. S.; Calder, S.; Ehlers, G.; Huq, A.; Kimber, S. A. J.; Arachchige, H. Suriya; Poudel, L.; McGuire, M. A.; Mandrus, D.; Christianson, A. D.

2018-04-01

The physical properties of the spinel LiGaCr4S8 have been studied with neutron diffraction, x-ray diffraction, magnetic susceptibility, and heat capacity measurements. The neutron diffraction and synchrotron x-ray diffraction data reveal negative thermal expansion (NTE) below 111(4) K. The magnetic susceptibility deviates from Curie-Weiss behavior with the onset of NTE. At low temperature a broad peak in the magnetic susceptibility at 10.3(3) K is accompanied by the return of normal thermal expansion. First-principles calculations find a strong coupling between the lattice and the simulated magnetic ground state. These results indicate strong magnetoelastic coupling in LiGaCr4S8 .

Quasiparticle Energy in a Strongly Interacting Homogeneous Bose-Einstein Condensate.

PubMed

Lopes, Raphael; Eigen, Christoph; Barker, Adam; Viebahn, Konrad G H; Robert-de-Saint-Vincent, Martin; Navon, Nir; Hadzibabic, Zoran; Smith, Robert P

2017-05-26

Using two-photon Bragg spectroscopy, we study the energy of particlelike excitations in a strongly interacting homogeneous Bose-Einstein condensate, and observe dramatic deviations from Bogoliubov theory. In particular, at large scattering length a the shift of the excitation resonance from the free-particle energy changes sign from positive to negative. For an excitation with wave number q, this sign change occurs at a≈4/(πq), in agreement with the Feynman energy relation and the static structure factor expressed in terms of the two-body contact. For a≳3/q we also see a breakdown of this theory, and better agreement with calculations based on the Wilson operator product expansion. Neither theory explains our observations across all interaction regimes, inviting further theoretical efforts.

Particle Orbit Analysis in the Finite Beta Plasma of the Large Helical Device using Real Coordinates

NASA Astrophysics Data System (ADS)

Seki, Ryousuke; Matsumoto, Yutaka; Suzuki, Yasuhiro; Watanabe, Kiyomasa; Itagaki, Masafumi

High-energy particles in a finite beta plasma of the Large Helical Device (LHD) are numerically traced in a real coordinate system. We investigate particle orbits by changing the beta value and/or the magnetic field strength. No significant difference is found in the particle orbit classifications between the vacuum magnetic field and the finite beta plasma cases. The deviation of a banana orbit from the flux surfaces strongly depends on the beta value, although the deviation of the orbit of a passing particle is independent of the beta value. In addition, the deviation of the orbit of the passing particle, rather than that of the banana-orbit particles, depends on the magnetic field strength. We also examine the effect of re-entering particles, which repeatedly pass in and out of the last closed flux surface, in the finite beta plasma of the LHD. It is found that the number of re-entering particles in the finite beta plasma is larger than that in the vacuum magnetic field. As a result, the role of reentering particles in the finite beta plasma of the LHD is more important than that in the vacuum magnetic field, and the effect of the charge-exchange reaction on particle confinement in the finite beta plasma is large.

Flight of frigatebirds inside clouds - energy gain, stability and control.

PubMed

Sachs, Gottfried; Weimerskirch, Henri

2018-07-07

Investigating the unique ability of frigatebirds of flying inside clouds, it is shown that they achieve a large energy gain by ascents to high altitudes in strong updrafts of trade cumulus clouds. Frigatebirds often perform that kind of flight, at daytime as well as in the night. This suggests that they are capable of flying inside clouds in a controlled and stabilized manner. The control requirements for ascents in terms of a circling flight in updrafts of trade cumulus clouds are analyzed, and the necessary aerodynamic control moments are determined. Based on a stability investigation, it is shown that there are restoring effects which act against disturbances causing possible deviations from the circling flight condition. The aerodynamic moments which effectuate that stabilization are identified. Furthermore, the problem of neutral azimuth stability which generally exists in the flight of birds and which is the reason for continually increasing deviations from the course is dealt with. It is shown for the circling flight mode of frigatebirds inside clouds that, here, deviations are small and remain constant, suggesting that a corrective control action is not required. This is particularly important for circling flight in conditions without a visual reference, like inside clouds. Copyright © 2018 Elsevier Ltd. All rights reserved.

Net Reaction Rate and Neutrino Cooling Rate for the Urca Process in Departure from Chemical Equilibrium in the Crust of Fast-accreting Neutron Stars

NASA Astrophysics Data System (ADS)

Wang, Wei-Hua; Huang, Xi; Zheng, Xiao-Ping

We discuss the effect of compression on Urca shells in the ocean and crust of accreting neutron stars, especially in superbursting sources. We find that Urca shells may be deviated from chemical equilibrium in neutron stars which accrete at several tenths of the local Eddington accretion rate. The deviation depends on the energy threshold of the parent and daughter nuclei, the transition strength, the temperature, and the local accretion rate. In a typical crust model of accreting neutron stars, the chemical departures range from a few tenths of kBT to tens of kBT for various Urca pairs. If the Urca shell can exist in crusts of accreting neutron stars, compression may enhance the net neutrino cooling rate by a factor of about 1-2 relative to the neutrino emissivity in chemical equilibrium. For some cases, such as Urca pairs with small energy thresholds and/or weak transition strength, the large chemical departure may result in net heating rather than cooling, although the released heat can be small. Strong Urca pairs in the deep crust are hard to be deviated even in neutron stars accreting at the local Eddington accretion rate.

Alfven wave refraction by interplanetary inhomogeneities

NASA Technical Reports Server (NTRS)

Daily, W. D.

1973-01-01

Pioneer 6 magnetic data reveals that the propagation direction of Alfven waves in the interplanetary medium is strongly oriented along the ambient field. Magnetic fluctuations of frequencies up to 1/30 sec in the spacecraft frame are shown to satisfy a necessary condition for Alfven wave normal. It appears from this analysis that geometrical hydromagnetics may satisfactorily describe deviation of the wave normal from the background field. The rotational discontinuity is likely also to propagate along the field lines.

Wind speed statistics for Goldstone, California, anemometer sites

NASA Technical Reports Server (NTRS)

Berg, M.; Levy, R.; Mcginness, H.; Strain, D.

1981-01-01

An exploratory wind survey at an antenna complex was summarized statistically for application to future windmill designs. Data were collected at six locations from a total of 10 anemometers. Statistics include means, standard deviations, cubes, pattern factors, correlation coefficients, and exponents for power law profile of wind speed. Curves presented include: mean monthly wind speeds, moving averages, and diurnal variation patterns. It is concluded that three of the locations have sufficiently strong winds to justify consideration for windmill sites.

Anomalous optogalvanic line shapes of argon metastable transitions in a hollow cathode lamp

NASA Technical Reports Server (NTRS)

Ruyten, W. M.

1993-01-01

Anomalous optogalvanic line shapes were observed in a commercial hollow cathode lamp containing argon buffer gas. Deviations from Gaussian line shapes were particularly strong for transitions originating from the 3P2 metastable level of argon. The anomalous line shapes can be described reasonably well by the assumption that two regions in the discharge are excited simultaneously, each giving rise to a purely Gaussian line shape, but with different polarities, amplitudes, and linewidths.

Retirement investment theory explains patterns in songbird nest-site choice

USGS Publications Warehouse

Streby, Henry M.; Refsnider, Jeanine M.; Peterson, Sean M.; Andersen, David E.

2014-01-01

When opposing evolutionary selection pressures act on a behavioural trait, the result is often stabilizing selection for an intermediate optimal phenotype, with deviations from the predicted optimum attributed to tracking a moving target, development of behavioural syndromes or shifts in riskiness over an individual's lifetime. We investigated nest-site choice by female golden-winged warblers, and the selection pressures acting on that choice by two fitness components, nest success and fledgling survival. We observed strong and consistent opposing selection pressures on nest-site choice for maximizing these two fitness components, and an abrupt, within-season switch in the fitness component birds prioritize via nest-site choice, dependent on the time remaining for additional nesting attempts. We found that females consistently deviated from the predicted optimal behaviour when choosing nest sites because they can make multiple attempts at one fitness component, nest success, but only one attempt at the subsequent component, fledgling survival. Our results demonstrate a unique natural strategy for balancing opposing selection pressures to maximize total fitness. This time-dependent switch from high to low risk tolerance in nest-site choice maximizes songbird fitness in the same way a well-timed switch in human investor risk tolerance can maximize one's nest egg at retirement. Our results also provide strong evidence for the adaptive nature of songbird nest-site choice, which we suggest has been elusive primarily due to a lack of consideration for fledgling survival.

Diagnostics for insufficiencies of posterior calculations in Bayesian signal inference.

PubMed

Dorn, Sebastian; Oppermann, Niels; Ensslin, Torsten A

2013-11-01

We present an error-diagnostic validation method for posterior distributions in Bayesian signal inference, an advancement of a previous work. It transfers deviations from the correct posterior into characteristic deviations from a uniform distribution of a quantity constructed for this purpose. We show that this method is able to reveal and discriminate several kinds of numerical and approximation errors, as well as their impact on the posterior distribution. For this we present four typical analytical examples of posteriors with incorrect variance, skewness, position of the maximum, or normalization. We show further how this test can be applied to multidimensional signals.

Deviations from Newton's law in supersymmetric large extra dimensions

NASA Astrophysics Data System (ADS)

Callin, P.; Burgess, C. P.

2006-09-01

Deviations from Newton's inverse-squared law at the micron length scale are smoking-gun signals for models containing supersymmetric large extra dimensions (SLEDs), which have been proposed as approaches for resolving the cosmological constant problem. Just like their non-supersymmetric counterparts, SLED models predict gravity to deviate from the inverse-square law because of the advent of new dimensions at sub-millimeter scales. However SLED models differ from their non-supersymmetric counterparts in three important ways: (i) the size of the extra dimensions is fixed by the observed value of the dark energy density, making it impossible to shorten the range over which new deviations from Newton's law must be seen; (ii) supersymmetry predicts there to be more fields in the extra dimensions than just gravity, implying different types of couplings to matter and the possibility of repulsive as well as attractive interactions; and (iii) the same mechanism which is purported to keep the cosmological constant naturally small also keeps the extra-dimensional moduli effectively massless, leading to deviations from general relativity in the far infrared of the scalar-tensor form. We here explore the deviations from Newton's law which are predicted over micron distances, and show the ways in which they differ and resemble those in the non-supersymmetric case.

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

Wulff, J; Huggins, A

Purpose: The shape of a single beam in proton PBS influences the resulting dose distribution. Spot profiles are modelled as two-dimensional Gaussian (single/ double) distributions in treatment planning systems (TPS). Impact of slight deviations from an ideal Gaussian on resulting dose distributions is typically assumed to be small due to alleviation by multiple Coulomb scattering (MCS) in tissue and superposition of many spots. Quantitative limits are however not clear per se. Methods: A set of 1250 deliberately deformed profiles with sigma=4 mm for a Gaussian fit were constructed. Profiles and fit were normalized to the same area, resembling output calibrationmore » in the TPS. Depth-dependent MCS was considered. The deviation between deformed and ideal profiles was characterized by root-mean-squared deviation (RMSD), skewness/ kurtosis (SK) and full-width at different percentage of maximum (FWxM). The profiles were convolved with different fluence patterns (regular/ random) resulting in hypothetical dose distributions. The resulting deviations were analyzed by applying a gamma-test. Results were compared to measured spot profiles. Results: A clear correlation between pass-rate and profile metrics could be determined. The largest impact occurred for a regular fluence-pattern with increasing distance between single spots, followed by a random distribution of spot weights. The results are strongly dependent on gamma-analysis dose and distance levels. Pass-rates of >95% at 2%/2 mm and 40 mm depth (=70 MeV) could only be achieved for RMSD<10%, deviation in FWxM at 20% and root of quadratic sum of SK <0.8. As expected the results improve for larger depths. The trends were well resembled for measured spot profiles. Conclusion: All measured profiles from ProBeam sites passed the criteria. Given the fact, that beam-line tuning can result shape distortions, the derived criteria represent a useful QA tool for commissioning and design of future beam-line optics.« less

Correlational and thermodynamic properties of finite-temperature electron liquids in the hypernetted-chain approximation.

PubMed

Tanaka, Shigenori

2016-12-07

Correlational and thermodynamic properties of homogeneous electron liquids at finite temperatures are theoretically analyzed in terms of dielectric response formalism with the hypernetted-chain (HNC) approximation and its modified version. The static structure factor and the local-field correction to describe the strong Coulomb-coupling effects beyond the random-phase approximation are self-consistently calculated through solution to integral equations in the paramagnetic (spin unpolarized) and ferromagnetic (spin polarized) states. In the ground state with the normalized temperature θ=0, the present HNC scheme well reproduces the exchange-correlation energies obtained by quantum Monte Carlo (QMC) simulations over the whole fluid phase (the coupling constant r s ≤100), i.e., within 1% and 2% deviations from putative best QMC values in the paramagnetic and ferromagnetic states, respectively. As compared with earlier studies based on the Singwi-Tosi-Land-Sjölander and modified convolution approximations, some improvements on the correlation energies and the correlation functions including the compressibility sum rule are found in the intermediate to strong coupling regimes. When applied to the electron fluids at intermediate Fermi degeneracies (θ≈1), the static structure factors calculated in the HNC scheme show good agreements with the results obtained by the path integral Monte Carlo (PIMC) simulation, while a small negative region in the radial distribution function is observed near the origin, which may be associated with a slight overestimation for the exchange-correlation hole in the HNC approximation. The interaction energies are calculated for various combinations of density and temperature parameters ranging from strong to weak degeneracy and from weak to strong coupling, and the HNC values are then parametrized as functions of r s and θ. The HNC exchange-correlation free energies obtained through the coupling-constant integration show reasonable agreements with earlier results including the PIMC-based fitting over the whole fluid region at finite degeneracies in the paramagnetic state. In contrast, a systematic difference between the HNC and PIMC results is observed in the ferromagnetic state, which suggests a necessity of further studies on the exchange-correlation free energies from both aspects of analytical theory and simulation.

Identification of low-overpressure interval and its implication to hydrocarbon migration: Case study in the Yanan sag of the Qiongdongnan Basin, South China Sea

PubMed Central

Xu, Qinghai; Shi, Wanzhong; Xie, Yuhong; Wang, Zhenfeng; Li, Xusheng; Tong, Chuanxin

2017-01-01

The Qiongdongnan Basin is a strongly overpressured basin with the maximum pressure coefficient (the ratio of the actual pore pressure versus hydrostatic pressure at the same depth) over 2.27. However, there exists a widespread low-overpressure interval between the strong overpressure intervals in the Yanan Sag of western basin. The mechanisms of the low-overpressure interval are not well understood. Three main approaches, pore pressure test data and well-log analysis, pressure prediction based on the relationship between the deviation of the velocity and the pressure coefficients, and numerical modeling, were employed to illustrate the distribution and evolution of the low-overpressure interval. And we analyzed and explained the phenomenon of the low-overpressure interval that is both underlain and overlain by high overpressure internal. The low-overpressure interval between the strong overpressure intervals can be identified and modelled by drilling data of P-wave sonic and the mud weight, and the numerical modeling using the PetroMod software. Results show that the low-overpressure interval is mainly composed of sandstone sediments. The porosities of sandstone in the low-overpressure interval primarily range from 15%-20%, and the permeabilities range from 10–100 md. Analysis of the geochemical parameters of C1, iC4/nC4, ΔR3, and numerical modeling shows that oil and gas migrated upward into the sandstone in the low-overpressure interval, and then migrated along the sandstone of low-overpressure interval into the Yacheng uplift. The low-overpressure both underlain and overlain by overpressure resulted from the fluids migrating along the sandstones in the low-overpressure interval into the Yacheng uplift since 1.9Ma. The mudstone in the strong overpressure interval is good cap overlain the sandstone of low-overpressure interval, therefore up-dip pinchouts or isolated sandstone in the low-overpressure interval locating the migration path of oil and gas are good plays for hydrocarbon exploration. PMID:28934237

Strong gravitational lensing by a Konoplya-Zhidenko rotating non-Kerr compact object

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

Wang, Shangyun; Chen, Songbai; Jing, Jiliang, E-mail: shangyun_wang@163.com, E-mail: csb3752@hunnu.edu.cn, E-mail: jljing@hunnu.edu.cn

Konoplya and Zhidenko have proposed recently a rotating non-Kerr black hole metric beyond General Relativity and make an estimate for the possible deviations from the Kerr solution with the data of GW 150914. We here study the strong gravitational lensing in such a rotating non-Kerr spacetime with an extra deformation parameter. We find that the condition of existence of horizons is not inconsistent with that of the marginally circular photon orbit. Moreover, the deflection angle of the light ray near the weakly naked singularity covered by the marginally circular orbit diverges logarithmically in the strong-field limit. In the case ofmore » the completely naked singularity, the deflection angle near the singularity tends to a certain finite value, whose sign depends on the rotation parameter and the deformation parameter. These properties of strong gravitational lensing are different from those in the Johannsen-Psaltis rotating non-Kerr spacetime and in the Janis-Newman-Winicour spacetime. Modeling the supermassive central object of the Milk Way Galaxy as a Konoplya-Zhidenko rotating non-Kerr compact object, we estimated the numerical values of observables for the strong gravitational lensing including the time delay between two relativistic images.« less

Threshold and variability properties of matrix frequency-doubling technology and standard automated perimetry in glaucoma.

PubMed

Artes, Paul H; Hutchison, Donna M; Nicolela, Marcelo T; LeBlanc, Raymond P; Chauhan, Balwantray C

2005-07-01

To compare test results from second-generation Frequency-Doubling Technology perimetry (FDT2, Humphrey Matrix; Carl-Zeiss Meditec, Dublin, CA) and standard automated perimetry (SAP) in patients with glaucoma. Specifically, to examine the relationship between visual field sensitivity and test-retest variability and to compare total and pattern deviation probability maps between both techniques. Fifteen patients with glaucoma who had early to moderately advanced visual field loss with SAP (mean MD, -4.0 dB; range, +0.2 to -16.1) were enrolled in the study. Patients attended three sessions. During each session, one eye was examined twice with FDT2 (24-2 threshold test) and twice with SAP (Swedish Interactive Threshold Algorithm [SITA] Standard 24-2 test), in random order. We compared threshold values between FDT2 and SAP at test locations with similar visual field coordinates. Test-retest variability, established in terms of test-retest intervals and standard deviations (SDs), was investigated as a function of visual field sensitivity (estimated by baseline threshold and mean threshold, respectively). The magnitude of visual field defects apparent in total and pattern deviation probability maps were compared between both techniques by ordinal scoring. The global visual field indices mean deviation (MD) and pattern standard deviation (PSD) of FDT2 and SAP correlated highly (r > 0.8; P < 0.001). At test locations with high sensitivity (>25 dB with SAP), threshold estimates from FDT2 and SAP exhibited a close, linear relationship, with a slope of approximately 2.0. However, at test locations with lower sensitivity, the relationship was much weaker and ceased to be linear. In comparison with FDT2, SAP showed a slightly larger proportion of test locations with absolute defects (3.0% vs. 2.2% with SAP and FDT2, respectively, P < 0.001). Whereas SAP showed a significant increase in test-retest variability at test locations with lower sensitivity (P < 0.001), there was no relationship between variability and sensitivity with FDT2 (P = 0.46). In comparison with SAP, FDT2 exhibited narrower test-retest intervals at test locations with lower sensitivity (SAP thresholds <25 dB). A comparison of the total and pattern deviation maps between both techniques showed that the total deviation analyses of FDT2 may slightly underestimate the visual field loss apparent with SAP. However, the pattern-deviation maps of both instruments agreed well with each other. The test-retest variability of FDT2 is uniform over the measurement range of the instrument. These properties may provide advantages for the monitoring of patients with glaucoma that should be investigated in longitudinal studies.

pH-Dependent Interactions in Dimers Govern the Mechanics and Structure of von Willebrand Factor.

PubMed

Müller, Jochen P; Löf, Achim; Mielke, Salomé; Obser, Tobias; Bruetzel, Linda K; Vanderlinden, Willem; Lipfert, Jan; Schneppenheim, Reinhard; Benoit, Martin

2016-07-26

Von Willebrand factor (VWF) is a multimeric plasma glycoprotein that is activated for hemostasis by increased hydrodynamic forces at sites of vascular injury. Here, we present data from atomic force microscopy-based single-molecule force measurements, atomic force microscopy imaging, and small-angle x-ray scattering to show that the structure and mechanics of VWF are governed by multiple pH-dependent interactions with opposite trends within dimeric subunits. In particular, the recently discovered strong intermonomer interaction, which induces a firmly closed conformation of dimers and crucially involves the D4 domain, was observed with highest frequency at pH 7.4, but was essentially absent at pH values below 6.8. However, below pH 6.8, the ratio of compact dimers increased with decreasing pH, in line with a previous transmission electron microscopy study. These findings indicated that the compactness of dimers at pH values below 6.8 is promoted by other interactions that possess low mechanical resistance compared with the strong intermonomer interaction. By investigating deletion constructs, we found that compactness under acidic conditions is primarily mediated by the D4 domain, i.e., remarkably by the same domain that also mediates the strong intermonomer interaction. As our data suggest that VWF has the highest mechanical resistance at physiological pH, local deviations from physiological pH (e.g., at sites of vascular injury) may represent a means to enhance VWF's hemostatic activity where needed. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Exploring one-particle orbitals in large many-body localized systems

NASA Astrophysics Data System (ADS)

Villalonga, Benjamin; Yu, Xiongjie; Luitz, David J.; Clark, Bryan K.

2018-03-01

Strong disorder in interacting quantum systems can give rise to the phenomenon of many-body localization (MBL), which defies thermalization due to the formation of an extensive number of quasilocal integrals of motion. The one-particle operator content of these integrals of motion is related to the one-particle orbitals (OPOs) of the one-particle density matrix and shows a strong signature across the MBL transition as recently pointed out by Bera et al. [Phys. Rev. Lett. 115, 046603 (2015), 10.1103/PhysRevLett.115.046603; Ann. Phys. 529, 1600356 (2017), 10.1002/andp.201600356]. We study the properties of the OPOs of many-body eigenstates of an MBL system in one dimension. Using shift-and-invert MPS, a matrix product state method to target highly excited many-body eigenstates introduced previously [Phys. Rev. Lett. 118, 017201 (2017), 10.1103/PhysRevLett.118.017201], we are able to obtain accurate results for large systems of sizes up to L =64 . We find that the OPOs drawn from eigenstates at different energy densities have high overlap and their occupations are correlated with the energy of the eigenstates. Moreover, the standard deviation of the inverse participation ratio of these orbitals is maximal at the nose of the mobility edge. Also, the OPOs decay exponentially in real space, with a correlation length that increases at low disorder. In addition, we find that the probability distribution of the strength of the large-range coupling constants of the number operators generated by the OPOs approach a log-uniform distribution at strong disorder.

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

PubMed

Zhang, Dawei; Liu, Chungen

2016-04-12

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

Revision of earthquake hypocenter locations in GEOFON bulletin data using global source-specific station terms technique

NASA Astrophysics Data System (ADS)

Nooshiri, N.; Saul, J.; Heimann, S.; Tilmann, F. J.; Dahm, T.

2015-12-01

The use of a 1D velocity model for seismic event location is often associated with significant travel-time residuals. Particularly for regional stations in subduction zones, where the velocity structure strongly deviates from the assumed 1D model, residuals of up to ±10 seconds are observed even for clear arrivals, which leads to strongly biased locations. In fact, due to mostly regional travel-time anomalies, arrival times at regional stations do not match the location obtained with teleseismic picks, and vice versa. If the earthquake is weak and only recorded regionally, or if fast locations based on regional stations are needed, the location may be far off the corresponding teleseismic location. In this case, implementation of travel-time corrections may leads to a reduction of the travel-time residuals at regional stations and, in consequence, significantly improve the relative location accuracy. Here, we have extended the source-specific station terms (SSST) technique to regional and teleseismic distances and adopted the algorithm for probabilistic, non-linear, global-search earthquake location. The method has been applied to specific test regions using P and pP phases from the GEOFON bulletin data for all available station networks. By using this method, a set of timing corrections has been calculated for each station varying as a function of source position. In this way, an attempt is made to correct for the systematic errors, introduced by limitations and inaccuracies in the assumed velocity structure, without solving for a new earth model itself. In this presentation, we draw on examples of the application of this global SSST technique to relocate earthquakes from the Tonga-Fiji subduction zone and from the Chilean margin. Our results have been showing a considerable decrease of the root-mean-square (RMS) residual in earthquake location final catalogs, a major reduction of the median absolute deviation (MAD) of the travel-time residuals at regional stations and sharper images of the seismicity compared to the initial locations.

Human sensorimotor tracking of continuous subliminal deviations from isochrony.

PubMed

Madison, Guy; Merker, Björn

2004-11-03

We show that people continuously react to time perturbations in the range 3-96 ms in otherwise isochronous sound sequences. Musically trained and untrained participants were asked to synchronize with a sequence of sounds, and these two groups performed almost equally below the threshold for conscious detection of the perturbations. Above this threshold the motor reactions accounted for a larger proportion of the stimulus deviations in musically trained participants.

Is there a correlation between nasal septum deviation and maxillary transversal deficiency? A retrospective study on prepubertal subjects.

PubMed

Ballanti, Fabiana; Baldini, Alberto; Ranieri, Salvatore; Nota, Alessandro; Cozza, Paola

2016-04-01

Deviated nasal septum may cause a reduction of the nasal airflow, thus, during the craniofacial development, a reduced nasal airflow could originate a chronic mouth-breathing pattern, related with moderate to severe maxillary constriction. The aim of this retrospective study is to analyze the correlation between maxillary transverse deficiency and nasal septum deviation. Frontal cephalograms were performed on 66 posterior-anterior radiographs of subjects (34M, 32F; mean age 9.95±2.50 years) with maxillary transverse deficiency and on a control group of 31 posterior-anterior radiographs of subjects (13M, 18F; 9.29±2.08 years). Angular parameters of the nasal cavities were recorded and compared between the two groups using a Student's t-test. Generally all the parameters are very similar between the two groups except for the ASY angle that differs for about the 27%; anyway the Student's t-test showed no statistically significant differences between the two groups (mostly p>0.20). This study failed to show an association between transverse maxillary deficiencies and nasal septum deviations. Moreover, no significant differences were found between the mean nasal cavities dimensions in subjects with transverse maxillary deficiency and the control group. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Genome-wide Scan of 29,141 African Americans Finds No Evidence of Directional Selection since Admixture

PubMed Central

Bhatia, Gaurav; Tandon, Arti; Patterson, Nick; Aldrich, Melinda C.; Ambrosone, Christine B.; Amos, Christopher; Bandera, Elisa V.; Berndt, Sonja I.; Bernstein, Leslie; Blot, William J.; Bock, Cathryn H.; Caporaso, Neil; Casey, Graham; Deming, Sandra L.; Diver, W. Ryan; Gapstur, Susan M.; Gillanders, Elizabeth M.; Harris, Curtis C.; Henderson, Brian E.; Ingles, Sue A.; Isaacs, William; De Jager, Phillip L.; John, Esther M.; Kittles, Rick A.; Larkin, Emma; McNeill, Lorna H.; Millikan, Robert C.; Murphy, Adam; Neslund-Dudas, Christine; Nyante, Sarah; Press, Michael F.; Rodriguez-Gil, Jorge L.; Rybicki, Benjamin A.; Schwartz, Ann G.; Signorello, Lisa B.; Spitz, Margaret; Strom, Sara S.; Tucker, Margaret A.; Wiencke, John K.; Witte, John S.; Wu, Xifeng; Yamamura, Yuko; Zanetti, Krista A.; Zheng, Wei; Ziegler, Regina G.; Chanock, Stephen J.; Haiman, Christopher A.; Reich, David; Price, Alkes L.

2014-01-01

The extent of recent selection in admixed populations is currently an unresolved question. We scanned the genomes of 29,141 African Americans and failed to find any genome-wide-significant deviations in local ancestry, indicating no evidence of selection influencing ancestry after admixture. A recent analysis of data from 1,890 African Americans reported that there was evidence of selection in African Americans after their ancestors left Africa, both before and after admixture. Selection after admixture was reported on the basis of deviations in local ancestry, and selection before admixture was reported on the basis of allele-frequency differences between African Americans and African populations. The local-ancestry deviations reported by the previous study did not replicate in our very large sample, and we show that such deviations were expected purely by chance, given the number of hypotheses tested. We further show that the previous study’s conclusion of selection in African Americans before admixture is also subject to doubt. This is because the FST statistics they used were inflated and because true signals of unusual allele-frequency differences between African Americans and African populations would be best explained by selection that occurred in Africa prior to migration to the Americas. PMID:25242497

Clustering and heterogeneous dynamics in a kinetic Monte Carlo model of self-propelled hard disks

NASA Astrophysics Data System (ADS)

Levis, Demian; Berthier, Ludovic

2014-06-01

We introduce a kinetic Monte Carlo model for self-propelled hard disks to capture with minimal ingredients the interplay between thermal fluctuations, excluded volume, and self-propulsion in large assemblies of active particles. We analyze in detail the resulting (density, self-propulsion) nonequilibrium phase diagram over a broad range of parameters. We find that purely repulsive hard disks spontaneously aggregate into fractal clusters as self-propulsion is increased and rationalize the evolution of the average cluster size by developing a kinetic model of reversible aggregation. As density is increased, the nonequilibrium clusters percolate to form a ramified structure reminiscent of a physical gel. We show that the addition of a finite amount of noise is needed to trigger a nonequilibrium phase separation, showing that demixing in active Brownian particles results from a delicate balance between noise, interparticle interactions, and self-propulsion. We show that self-propulsion has a profound influence on the dynamics of the active fluid. We find that the diffusion constant has a nonmonotonic behavior as self-propulsion is increased at finite density and that activity produces strong deviations from Fickian diffusion that persist over large time scales and length scales, suggesting that systems of active particles generically behave as dynamically heterogeneous systems.

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

Xiang, Z.; Lawson, B.; Asaba, T.

The Kondo insulator samarium hexaboride (SmB 6) has been intensely studied in recent years as a potential candidate of a strongly correlated topological insulator. One of the most exciting phenomena observed in SmB 6 is the clear quantum oscillations appearing in magnetic torque at a low temperature despite the insulating behavior in resistance. These quantum oscillations show multiple frequencies and varied effective masses. The origin of quantum oscillation is, however, still under debate with evidence of both two-dimensional Fermi surfaces and three-dimensional Fermi surfaces. Here, we carry out angle-resolved torque magnetometry measurements in a magnetic field up to 45 Tmore » and a temperature range down to 40 mK. With the magnetic field rotated in the (010) plane, the quantum oscillation frequency of the strongest oscillation branch shows a fourfold rotational symmetry. However, in the angular dependence of the amplitude of the same branch, this fourfold symmetry is broken and, instead, a twofold symmetry shows up, which is consistent with the prediction of a two-dimensional Lifshitz-Kosevich model. No deviation of Lifshitz-Kosevich behavior is observed down to 40 mK. Our results suggest the existence of multiple light-mass surface states in SmB 6, with their mobility significantly depending on the surface disorder level.« less

Bulk Rotational Symmetry Breaking in Kondo Insulator SmB 6

DOE PAGES

Xiang, Z.; Lawson, B.; Asaba, T.; ...

2017-09-25

The Kondo insulator samarium hexaboride (SmB 6) has been intensely studied in recent years as a potential candidate of a strongly correlated topological insulator. One of the most exciting phenomena observed in SmB 6 is the clear quantum oscillations appearing in magnetic torque at a low temperature despite the insulating behavior in resistance. These quantum oscillations show multiple frequencies and varied effective masses. The origin of quantum oscillation is, however, still under debate with evidence of both two-dimensional Fermi surfaces and three-dimensional Fermi surfaces. Here, we carry out angle-resolved torque magnetometry measurements in a magnetic field up to 45 Tmore » and a temperature range down to 40 mK. With the magnetic field rotated in the (010) plane, the quantum oscillation frequency of the strongest oscillation branch shows a fourfold rotational symmetry. However, in the angular dependence of the amplitude of the same branch, this fourfold symmetry is broken and, instead, a twofold symmetry shows up, which is consistent with the prediction of a two-dimensional Lifshitz-Kosevich model. No deviation of Lifshitz-Kosevich behavior is observed down to 40 mK. Our results suggest the existence of multiple light-mass surface states in SmB 6, with their mobility significantly depending on the surface disorder level.« less

Reversal magnetization dependence with the Cr and Fe oxidation states in YFe1-xCrxO3 (0≤x≤1) perovskites

NASA Astrophysics Data System (ADS)

Fabian, F. A.; Pedra, P. P.; Moura, K. O.; Duque, J. G. S.; Meneses, C. T.

2016-06-01

In this work, we have carried out a detailed study of the magnetic and structural properties of YFe1-xCrxO3 (0≤x≤1) samples with orthorhombic structure obtained by co-precipitation method. Analysis of X-ray diffraction data using Rietveld refinement show that all samples present an orthorhombic crystal system with space group Pnma. Besides, we have observed a reduction of unit cell volume with increasing of the Cr concentration. SEM images show the formation of grains of micrometer order. X-ray Absorption near edge spectroscopy (XANES) measurements show a shift of absorption edge which can be indicate there is (i) different oxidation states to Fe and Cr ions and/or (ii) a changing in the point symmetry of Fe and Cr ions to the compounds. The magnetization measurements indicate a continuous decreasing of the magnetic transition temperature as function of chromium doping. The reversal magnetization effect was observed to concentrations around x=0.5. Besides, the deviation of the Curie-Weiss law and a weak ferromagnetic behavior observed at room temperature in the M vs H curves can be attributed to the strong magnetic interactions between the transition metals with different oxidation states.

Chromosome 3p loss of heterozygosity is associated with a unique metabolic network in clear cell renal carcinoma

PubMed Central

Gatto, Francesco; Nookaew, Intawat; Nielsen, Jens

2014-01-01

Several common oncogenic pathways have been implicated in the emergence of renowned metabolic features in cancer, which in turn are deemed essential for cancer proliferation and survival. However, the extent to which different cancers coordinate their metabolism to meet these requirements is largely unexplored. Here we show that even in the heterogeneity of metabolic regulation a distinct signature encompassed most cancers. On the other hand, clear cell renal cell carcinoma (ccRCC) strongly deviated in terms of metabolic gene expression changes, showing widespread down-regulation. We observed a metabolic shift that associates differential regulation of enzymes in one-carbon metabolism with high tumor stage and poor clinical outcome. A significant yet limited set of metabolic genes that explained the partial divergence of ccRCC metabolism correlated with loss of von Hippel-Lindau tumor suppressor (VHL) and a potential activation of signal transducer and activator of transcription 1. Further network-dependent analyses revealed unique defects in nucleotide, one-carbon, and glycerophospholipid metabolism at the transcript and protein level, which contrasts findings in other tumors. Notably, this behavior is recapitulated by recurrent loss of heterozygosity in multiple metabolic genes adjacent to VHL. This study therefore shows how loss of heterozygosity, hallmarked by VHL deletion in ccRCC, may uniquely shape tumor metabolism. PMID:24550497

A global model simulation for 3-D radiative transfer impact on surface hydrology over the Sierra Nevada and Rocky Mountains

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

Lee, W. -L.; Gu, Y.; Liou, K. N.

2015-05-19

We investigate 3-D mountain effects on solar flux distributions and their impact on surface hydrology over the western United States, specifically the Rocky Mountains and the Sierra Nevada, using the global CCSM4 (Community Climate System Model version 4; Community Atmosphere Model/Community Land Model – CAM4/CLM4) with a 0.23° × 0.31° resolution for simulations over 6 years. In a 3-D radiative transfer parameterization, we have updated surface topography data from a resolution of 1 km to 90 m to improve parameterization accuracy. In addition, we have also modified the upward-flux deviation (3-D–PP (plane-parallel)) adjustment to ensure that the energy balance atmore » the surface is conserved in global climate simulations based on 3-D radiation parameterization. We show that deviations in the net surface fluxes are not only affected by 3-D mountains but also influenced by feedbacks of cloud and snow in association with the long-term simulations. Deviations in sensible heat and surface temperature generally follow the patterns of net surface solar flux. The monthly snow water equivalent (SWE) deviations show an increase in lower elevations due to reduced snowmelt, leading to a reduction in cumulative runoff. Over higher-elevation areas, negative SWE deviations are found because of increased solar radiation available at the surface. Simulated precipitation increases for lower elevations, while it decreases for higher elevations, with a minimum in April. Liquid runoff significantly decreases at higher elevations after April due to reduced SWE and precipitation.« less

The Effects of Marginal Deviations on Behavioral Development.

PubMed

Caprara, Gian Vittorio; Dodge, Kenneth A; Pastorelli, Concetta; Zelli, Arnaldo

2006-01-01

This investigation was conceptually framed within the theory of marginal deviations (Caprara & Zimbardo, 1996) and sought evidence for the general hypothesis that some children who initially show marginal behavioral problems may, over time, develop more serious problems depending partly on other personal and behavioral characteristics. To this end, the findings of two studies conducted, respectively, with American elementary school children and Italian middle school students are reviewed. These two studies show that hyperactivity, cognitive difficulties, low special preference, and lack of prosocial behavior increase a child's risk for growth in aggressive behavior over several school years. More importantly, they also show that equivalent levels of these risk factors have a greater impact on the development of children who, early on, were marginally aggressive.

Does a continuous solid nucleus exist in comets.

NASA Technical Reports Server (NTRS)

Lyttleton, R. A.

1972-01-01

The implication of actual cometary observations for the physical nature of comets is briefly reviewed, bringing out the complete conflict with observation of the ice-dust solid nucleus model put forward in recent years as representing the fundamental structure of comets. That under increasing solar heat the nucleus develops an expanding atmosphere is inconsistent with the well-established phenomenon that the coma contracts with decreasing distance from the sun. Several comets remaining always beyond Mars have nevertheless been strongly active and produced fine tails. That some comets show at times a star-like point of light is readily explicable on the dust-cloud structure and by no means establishes that a solid nucleus exists. With the nucleus-area corresponding not to a small solid mass but to an optical phenomenon, there would be no reason to expect that it would describe a precise dynamical orbit. On the hypothesis of a nucleus, it is necessary to postulate further some internal jet-propulsion mechanism to account for the orbital deviations.

Freezing and melting water in lamellar structures.

PubMed Central

Gleeson, J T; Erramilli, S; Gruner, S M

1994-01-01

The manner in which ice forms in lamellar suspensions of dielaidoylphosphatidylethanolamine, dielaidoylphosphatidylcholine, and dioleoylphosphatidylcholine in water depends strongly on the water fraction. For weight fractions between 15 and 9%, the freezing and melting temperatures are significantly depressed below 0 degree C. The ice exhibits a continuous melting transition spanning as much as 20 degrees C. When the water weight fraction is below 9%, ice never forms at temperatures as low as -40 degrees C. We show that when water contained in a lamellar lipid suspension freezes, the ice is not found between the bilayers; it exists as pools of crystalline ice in equilibrium with the bound water associated with the polar lipid headgroups. We have used this effect, together with the known chemical potential of ice, to measure hydration forces between lipid bilayers. We find exponentially decaying hydration repulsion when the bilayers are less than about 7 A apart. For larger separations, we find significant deviations from single exponential decay. PMID:7948683

Early warning of changing drinking water quality by trend analysis.

PubMed

Tomperi, Jani; Juuso, Esko; Leiviskä, Kauko

2016-06-01

Monitoring and control of water treatment plants play an essential role in ensuring high quality drinking water and avoiding health-related problems or economic losses. The most common quality variables, which can be used also for assessing the efficiency of the water treatment process, are turbidity and residual levels of coagulation and disinfection chemicals. In the present study, the trend indices are developed from scaled measurements to detect warning signs of changes in the quality variables of drinking water and some operating condition variables that strongly affect water quality. The scaling is based on monotonically increasing nonlinear functions, which are generated with generalized norms and moments. Triangular episodes are classified with the trend index and its derivative. Deviation indices are used to assess the severity of situations. The study shows the potential of the described trend analysis as a predictive monitoring tool, as it provides an advantage over the traditional manual inspection of variables by detecting changes in water quality and giving early warnings.

Particle size dependence on magnetic and electrical properties of (Ni0.8Fe0.2)10C90 granular composites.

PubMed

Mandal, Guruprasad; Srinivas, V; Rao, V V

2011-03-01

The granular structure and electrical transport behavior of ball milled magnetic permalloy particles and graphite forming (Ni0.8Fe0.2)10C90 granular composites have been reported. Retaining the composite composition to be 90:10 and varying the particle size of permalloy, the electronic transport properties have been carried out down to 4 K under the external applied magnetic field of 50 kOe. All the samples show semiconducting like behavior and positive magnetoresistance (MR) in the temperature range 4-300 K. A strong anisotropic magnetoresistance in these samples has also been observed. The highest 31% longitudinal and 6.8% transverse magnetoresistance values have been observed in 40 hrs ball milled (Ni0.8Fe0.2)10C90 composite. From these studies, we suggest that the magnetic component present in the sample may not be playing a major role in obtaining large positive MR values, which is in deviation with the earlier reports.

Frequency-dependent solvent friction and torsional damping in liquid 1,2-difluoroethane

NASA Astrophysics Data System (ADS)

MacPhail, Richard A.; Monroe, Frances C.

1991-04-01

We have used Raman spectroscopy to study the torsional dynamics, rotational dynamics, and conformational solvation energy of liquid 1,2-difluoroethane. From the Raman intensities, we obtain Δ H(g-t) = -2.4±0.1 kcal/mol, indicating strong dipolar solvation of the gauche conformer. We analyze the Raman linewidths of the CCF bending bands to obtain the zero-frequency torsional damping coefficient or well friction for the gauche conformer, and from the linewidth of the torsion band we obtain the friction evaluated at the torsional frequency. The zero-frequency well friction shows deviations from hydrodynamic behavior reminiscent of those observed for barrier friction, whereas the high-frequency friction is considerably smaller in magnitude and independent of temperature and viscosity. The zero-frequency torsional friction correlates linearly with the rotational friction. It is argued that the small amplitude of the torsional fluctuations emphasizes the short distance, or high wavevector components of the solvent friction. Dielectric friction apparently does not contribute to the torsional friction at the observed frequencies.

Erosion properties of cohesive sediments in the Colorado River in Grand Canyon

USGS Publications Warehouse

Akahori, R.; Schmeeckle, M.W.; Topping, D.J.; Melis, T.S.

2008-01-01

Cohesive sediment deposits characterized by a high fraction of mud (silt plus clay) significantly affect the morphology and ecosystem of rivers. Potentially cohesive sediment samples were collected from deposits in the Colorado River in Marble and Grand Canyons. The erosion velocities of these samples were measured in a laboratory flume under varying boundary shear stresses. The non-dimensional boundary shear stress at which erosion commenced showed a systematic deviation from that of non-cohesive sediments at mud fractions greater than 0.2. An empirical relation for the boundary shear stress threshold of erosion as a function of mud fraction was proposed. The mass erosion rate was modelled using the Ariathurai-Partheniades equation. The erosion rate parameter of this equation was found to be a strong function of mud fraction. Under similar boundary shear stress and sediment supply conditions in the Colorado River, cohesive lateral eddy deposits formed of mud fractions in excess of 0.2 will erode less rapidly than non-cohesive deposits. Copyright ?? 2008 John Wiley & Sons, Ltd.

Dual mechanisms regulate ecosystem stability under decade-long warming and hay harvest

PubMed Central

Shi, Zheng; Xu, Xia; Souza, Lara; Wilcox, Kevin; Jiang, Lifen; Liang, Junyi; Xia, Jianyang; García-Palacios, Pablo; Luo, Yiqi

2016-01-01

Past global change studies have identified changes in species diversity as a major mechanism regulating temporal stability of production, measured as the ratio of the mean to the standard deviation of community biomass. However, the dominant plant functional group can also strongly determine the temporal stability. Here, in a grassland ecosystem subject to 15 years of experimental warming and hay harvest, we reveal that warming increases while hay harvest decreases temporal stability. This corresponds with the biomass of the dominant C4 functional group being higher under warming and lower under hay harvest. As a secondary mechanism, biodiversity also explains part of the variation in temporal stability of production. Structural equation modelling further shows that warming and hay harvest regulate temporal stability through influencing both temporal mean and variation of production. Our findings demonstrate the joint roles that dominant plant functional group and biodiversity play in regulating the temporal stability of an ecosystem under global change. PMID:27302085

Application of recurrent neural networks for drought projections in California

NASA Astrophysics Data System (ADS)

Le, J. A.; El-Askary, H. M.; Allali, M.; Struppa, D. C.

2017-05-01

We use recurrent neural networks (RNNs) to investigate the complex interactions between the long-term trend in dryness and a projected, short but intense, period of wetness due to the 2015-2016 El Niño. Although it was forecasted that this El Niño season would bring significant rainfall to the region, our long-term projections of the Palmer Z Index (PZI) showed a continuing drought trend, contrasting with the 1998-1999 El Niño event. RNN training considered PZI data during 1896-2006 that was validated against the 2006-2015 period to evaluate the potential of extreme precipitation forecast. We achieved a statistically significant correlation of 0.610 between forecasted and observed PZI on the validation set for a lead time of 1 month. This gives strong confidence to the forecasted precipitation indicator. The 2015-2016 El Niño season proved to be relatively weak as compared with the 1997-1998, with a peak PZI anomaly of 0.242 standard deviations below historical averages, continuing drought conditions.

Negative Pressure Vitrification of the Isochorically Confined Liquid in Nanopores.

PubMed

Adrjanowicz, K; Kaminski, K; Koperwas, K; Paluch, M

2015-12-31

Dielectric relaxation studies for model glass-forming liquids confined to nanoporous alumina matrices were examined together with high-pressure results. For confined liquids which show the deviation from bulk dynamics upon approaching the glass transition (the change from the Vogel-Fulcher-Tammann to the Arrhenius law), we have observed a striking agreement between the temperature dependence of the α-relaxation time in the Arrhenius-like region and the isochoric relaxation times extrapolated from the positive range of pressure to the negative pressure domain. Our finding provides strong evidence that glass-forming liquid confined to native nanopores enters the isochoric conditions once the mobility of the interfacial layer becomes frozen in. This results in the negative pressure effects on cooling. We also demonstrate that differences in the sensitivity of various glass-forming liquids to the "confinement effects" can be rationalized by considering the relative importance of thermal energy and density contributions in controlling the α-relaxation dynamics (the E(v)/E(p) ratio).

Flight parameter estimation using instantaneous frequency and time delay measurements from a three-element planar acoustic array.

PubMed

Lo, Kam W

2016-05-01

The acoustic signal emitted by a turbo-prop aircraft consists of a strong narrowband tone superimposed on a broadband random component. A ground-based three-element planar acoustic array can be used to estimate the full set of flight parameters of a turbo-prop aircraft in transit by measuring the time delay (TD) between the signal received at the reference sensor and the signal received at each of the other two sensors of the array over a sufficiently long period of time. This paper studies the possibility of using instantaneous frequency (IF) measurements from the reference sensor to improve the precision of the flight parameter estimates. A simplified Cramer-Rao lower bound analysis shows that the standard deviations in the estimates of the aircraft velocity and altitude can be greatly reduced when IF measurements are used together with TD measurements. Two flight parameter estimation algorithms that utilize both IF and TD measurements are formulated and their performances are evaluated using both simulated and real data.