angular cutoff global: Topics by Science.gov

Sample records for angular cutoff global

From Newton's Law to the Linear Boltzmann Equation Without Cut-Off

NASA Astrophysics Data System (ADS)

Ayi, Nathalie

2017-03-01

We provide a rigorous derivation of the linear Boltzmann equation without cut-off starting from a system of particles interacting via a potential with infinite range as the number of particles N goes to infinity under the Boltzmann-Grad scaling. More particularly, we will describe the motion of a tagged particle in a gas close to global equilibrium. The main difficulty in our context is that, due to the infinite range of the potential, a non-integrable singularity appears in the angular collision kernel, making no longer valid the single-use of Lanford's strategy. Our proof relies then on a combination of Lanford's strategy, of tools developed recently by Bodineau, Gallagher and Saint-Raymond to study the collision process, and of new duality arguments to study the additional terms associated with the long-range interaction, leading to some explicit weak estimates.
Global Well-Posedness of the Boltzmann Equation with Large Amplitude Initial Data

NASA Astrophysics Data System (ADS)

Duan, Renjun; Huang, Feimin; Wang, Yong; Yang, Tong

2017-07-01

The global well-posedness of the Boltzmann equation with initial data of large amplitude has remained a long-standing open problem. In this paper, by developing a new {L^∞_xL^1v\\cap L^∞_{x,v}} approach, we prove the global existence and uniqueness of mild solutions to the Boltzmann equation in the whole space or torus for a class of initial data with bounded velocity-weighted {L^∞} norm under some smallness condition on the {L^1_xL^∞_v} norm as well as defect mass, energy and entropy so that the initial data allow large amplitude oscillations. Both the hard and soft potentials with angular cut-off are considered, and the large time behavior of solutions in the {L^∞_{x,v}} norm with explicit rates of convergence are also studied.
Quantum Analysis of a Microcavity-Tuned Bloch Oscillator for Tunable Spontaneous Emission and Absorption of Terahertz Radiation

DTIC Science & Technology

2007-06-20

qz/qx) 2]1/2 is the mode dispersion relation, and ωc = qxc/ √ ε is the angular cutoff frequency. The guided mode wavelength is written as λ = λc/[(ωq...the guided modes corresponding to standing waves with respect to the X and Y axes designated by an integer pair m ,n, and propagating waves along...the angular cutoff frequency determined by the waveguide geometry. The guided mode wavelength is written as =c / q /c2−11/2, where c=2Lx is
The gyrotron - a natural source of high-power orbital angular momentum millimeter-wave beams

NASA Astrophysics Data System (ADS)

Thumm, M.; Sawant, A.; Choe, M. S.; Choi, E. M.

2017-08-01

Orbital angular momentum (OAM) of electromagnetic-wave beams provides further diversity to multiplexing in wireless communication. The present report shows that higher-order mode gyrotrons are natural sources of high-power OAM millimeter (mm) wave beams. The well-defined OAM of their rotating cavity modes operating at near cutoff frequency has been derived by photonic and electromagnetic wave approaches.
Microscopic study of spin cut-off factors of nuclear level densities

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

Gholami, M.; Kildir, M.; Behkami, A. N.

Level densities and spin cut-off factors have been investigated within the microscopic approach based on the BCS Hamiltonian. In particular, the spin cut-off parameters have been calculated at neutron binding energies over a large range of nuclear mass using the BCS theory. The spin cut-off parameters {sigma}{sup 2}(E) have also been obtained from the Gilbert and Cameron expression and from rigid body calculations. The results were compared with their corresponding macroscopic values. It was found that the values of {sigma}{sup 2}(E) did not increase smoothly with A as expected based on macroscopic theory. Instead, the values of {sigma}{sup 2}(E) showmore » structure reflecting the angular momentum of the shell model orbitals near the Fermi energy.« less
Effects of azimuth-symmetric acceptance cutoffs on the measured asymmetry in unpolarized Drell-Yan fixed-target experiments

NASA Astrophysics Data System (ADS)

Bianconi, A.; Bussa, M. P.; Destefanis, M.; Ferrero, L.; Greco, M.; Maggiora, M.; Spataro, S.

2013-04-01

Fixed-target unpolarized Drell-Yan experiments often feature an acceptance depending on the polar angle of the lepton tracks in the laboratory frame. Typically leptons are detected in a defined angular range, with a dead zone in the forward region. If the cutoffs imposed by the angular acceptance are independent of the azimuth, at first sight they do not appear dangerous for a measurement of the cos(2 φ) asymmetry, which is relevant because of its association with the violation of the Lam-Tung rule and with the Boer-Mulders function. On the contrary, direct simulations show that up to 10 percent asymmetries are produced by these cutoffs. These artificial asymmetries present qualitative features that allow them to mimic the physical ones. They introduce some model dependence in the measurements of the cos(2 φ) asymmetry, since a precise reconstruction of the acceptance in the Collins-Soper frame requires a Monte Carlo simulation, that in turn requires some detailed physical input to generate event distributions. Although experiments in the eighties seem to have been aware of this problem, the possibility of using the Boer-Mulders function as an input parameter in the extraction of transversity has much increased the requirements of precision on this measurement. Our simulations show that the safest approach to these measurements is a strong cutoff on the Collins-Soper polar angle. This reduces statistics, but does not necessarily decrease the precision in a measurement of the Boer-Mulders function.
Global warming precipitation accumulation increases above the current-climate cutoff scale

PubMed Central

Sahany, Sandeep; Stechmann, Samuel N.; Bernstein, Diana N.

2017-01-01

Precipitation accumulations, integrated over rainfall events, can be affected by both intensity and duration of the storm event. Thus, although precipitation intensity is widely projected to increase under global warming, a clear framework for predicting accumulation changes has been lacking, despite the importance of accumulations for societal impacts. Theory for changes in the probability density function (pdf) of precipitation accumulations is presented with an evaluation of these changes in global climate model simulations. We show that a simple set of conditions implies roughly exponential increases in the frequency of the very largest accumulations above a physical cutoff scale, increasing with event size. The pdf exhibits an approximately power-law range where probability density drops slowly with each order of magnitude size increase, up to a cutoff at large accumulations that limits the largest events experienced in current climate. The theory predicts that the cutoff scale, controlled by the interplay of moisture convergence variance and precipitation loss, tends to increase under global warming. Thus, precisely the large accumulations above the cutoff that are currently rare will exhibit increases in the warmer climate as this cutoff is extended. This indeed occurs in the full climate model, with a 3 °C end-of-century global-average warming yielding regional increases of hundreds of percent to >1,000% in the probability density of the largest accumulations that have historical precedents. The probabilities of unprecedented accumulations are also consistent with the extension of the cutoff. PMID:28115693
Global warming precipitation accumulation increases above the current-climate cutoff scale

NASA Astrophysics Data System (ADS)

Neelin, J. David; Sahany, Sandeep; Stechmann, Samuel N.; Bernstein, Diana N.

2017-02-01

Precipitation accumulations, integrated over rainfall events, can be affected by both intensity and duration of the storm event. Thus, although precipitation intensity is widely projected to increase under global warming, a clear framework for predicting accumulation changes has been lacking, despite the importance of accumulations for societal impacts. Theory for changes in the probability density function (pdf) of precipitation accumulations is presented with an evaluation of these changes in global climate model simulations. We show that a simple set of conditions implies roughly exponential increases in the frequency of the very largest accumulations above a physical cutoff scale, increasing with event size. The pdf exhibits an approximately power-law range where probability density drops slowly with each order of magnitude size increase, up to a cutoff at large accumulations that limits the largest events experienced in current climate. The theory predicts that the cutoff scale, controlled by the interplay of moisture convergence variance and precipitation loss, tends to increase under global warming. Thus, precisely the large accumulations above the cutoff that are currently rare will exhibit increases in the warmer climate as this cutoff is extended. This indeed occurs in the full climate model, with a 3 °C end-of-century global-average warming yielding regional increases of hundreds of percent to >1,000% in the probability density of the largest accumulations that have historical precedents. The probabilities of unprecedented accumulations are also consistent with the extension of the cutoff.
Global warming precipitation accumulation increases above the current-climate cutoff scale

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

Neelin, J. David; Sahany, Sandeep; Stechmann, Samuel N.

Precipitation accumulations, integrated over rainfall events, can be affected by both intensity and duration of the storm event. Thus, although precipitation intensity is widely projected to increase under global warming, a clear framework for predicting accumulation changes has been lacking, despite the importance of accumulations for societal impacts. Theory for changes in the probability density function (pdf) of precipitation accumulations is presented with an evaluation of these changes in global climate model simulations. We show that a simple set of conditions implies roughly exponential increases in the frequency of the very largest accumulations above a physical cutoff scale, increasing withmore » event size. The pdf exhibits an approximately power-law range where probability density drops slowly with each order of magnitude size increase, up to a cutoff at large accumulations that limits the largest events experienced in current climate. The theory predicts that the cutoff scale, controlled by the interplay of moisture convergence variance and precipitation loss, tends to increase under global warming. Thus, precisely the large accumulations above the cutoff that are currently rare will exhibit increases in the warmer climate as this cutoff is extended. This indeed occurs in the full climate model, with a 3 °C end-of-century global-average warming yielding regional increases of hundreds of percent to >1,000% in the probability density of the largest accumulations that have historical precedents. The probabilities of unprecedented accumulations are also consistent with the extension of the cutoff.« less
Global warming precipitation accumulation increases above the current-climate cutoff scale.

PubMed

Neelin, J David; Sahany, Sandeep; Stechmann, Samuel N; Bernstein, Diana N

2017-02-07

Precipitation accumulations, integrated over rainfall events, can be affected by both intensity and duration of the storm event. Thus, although precipitation intensity is widely projected to increase under global warming, a clear framework for predicting accumulation changes has been lacking, despite the importance of accumulations for societal impacts. Theory for changes in the probability density function (pdf) of precipitation accumulations is presented with an evaluation of these changes in global climate model simulations. We show that a simple set of conditions implies roughly exponential increases in the frequency of the very largest accumulations above a physical cutoff scale, increasing with event size. The pdf exhibits an approximately power-law range where probability density drops slowly with each order of magnitude size increase, up to a cutoff at large accumulations that limits the largest events experienced in current climate. The theory predicts that the cutoff scale, controlled by the interplay of moisture convergence variance and precipitation loss, tends to increase under global warming. Thus, precisely the large accumulations above the cutoff that are currently rare will exhibit increases in the warmer climate as this cutoff is extended. This indeed occurs in the full climate model, with a 3 °C end-of-century global-average warming yielding regional increases of hundreds of percent to >1,000% in the probability density of the largest accumulations that have historical precedents. The probabilities of unprecedented accumulations are also consistent with the extension of the cutoff.
Global warming precipitation accumulation increases above the current-climate cutoff scale

DOE PAGES

Neelin, J. David; Sahany, Sandeep; Stechmann, Samuel N.; ...

2017-01-23

Precipitation accumulations, integrated over rainfall events, can be affected by both intensity and duration of the storm event. Thus, although precipitation intensity is widely projected to increase under global warming, a clear framework for predicting accumulation changes has been lacking, despite the importance of accumulations for societal impacts. Theory for changes in the probability density function (pdf) of precipitation accumulations is presented with an evaluation of these changes in global climate model simulations. We show that a simple set of conditions implies roughly exponential increases in the frequency of the very largest accumulations above a physical cutoff scale, increasing withmore » event size. The pdf exhibits an approximately power-law range where probability density drops slowly with each order of magnitude size increase, up to a cutoff at large accumulations that limits the largest events experienced in current climate. The theory predicts that the cutoff scale, controlled by the interplay of moisture convergence variance and precipitation loss, tends to increase under global warming. Thus, precisely the large accumulations above the cutoff that are currently rare will exhibit increases in the warmer climate as this cutoff is extended. This indeed occurs in the full climate model, with a 3 °C end-of-century global-average warming yielding regional increases of hundreds of percent to >1,000% in the probability density of the largest accumulations that have historical precedents. The probabilities of unprecedented accumulations are also consistent with the extension of the cutoff.« less
Task Space Angular Velocity Blending for Real-Time Trajectory Generation

NASA Technical Reports Server (NTRS)

Volpe, Richard A. (Inventor)

1997-01-01

The invention is embodied in a method of controlling a robot manipulator moving toward a target frame F(sub 0) with a target velocity v(sub 0) including a linear target velocity v and an angular target velocity omega(sub 0) to smoothly and continuously divert the robot manipulator to a subsequent frame F(sub 1) by determining a global transition velocity v(sub 1), the global transition velocity including a linear transition velocity v(sub 1) and an angular transition velocity omega(sub 1), defining a blend time interval 2(tau)(sub 0) within which the global velocity of the robot manipulator is to be changed from a global target velocity v(sub 0) to the global transition velocity v(sub 1) and dividing the blend time interval 2(tau)(sub 0) into discrete time segments (delta)t. During each one of the discrete time segments delta t of the blend interval 2(tau)(sub 0), a blended global velocity v of the manipulator is computed as a blend of the global target velocity v(sub 0) and the global transition velocity v(sub 1), the blended global velocity v including a blended angular velocity omega and a blended linear velocity v, and then, the manipulator is rotated by an incremental rotation corresponding to an integration of the blended angular velocity omega over one discrete time segment (delta)t.
Large-Angular-Scale Clustering as a Clue to the Source of UHECRs

NASA Astrophysics Data System (ADS)

Berlind, Andreas A.; Farrar, Glennys R.

We explore what can be learned about the sources of UHECRs from their large-angular-scale clustering (referred to as their "bias" by the cosmology community). Exploiting the clustering on large scales has the advantage over small-scale correlations of being insensitive to uncertainties in source direction from magnetic smearing or measurement error. In a Cold Dark Matter cosmology, the amplitude of large-scale clustering depends on the mass of the system, with more massive systems such as galaxy clusters clustering more strongly than less massive systems such as ordinary galaxies or AGN. Therefore, studying the large-scale clustering of UHECRs can help determine a mass scale for their sources, given the assumption that their redshift depth is as expected from the GZK cutoff. We investigate the constraining power of a given UHECR sample as a function of its cutoff energy and number of events. We show that current and future samples should be able to distinguish between the cases of their sources being galaxy clusters, ordinary galaxies, or sources that are uncorrelated with the large-scale structure of the universe.
Achieving uniform efficient illumination with multiple asymmetric compound parabolic luminaires

NASA Astrophysics Data System (ADS)

Gordon, Jeffrey M.; Kashin, Peter

1994-01-01

Luminaire designs based on multiple asymmetric nonimaging compound parabolic reflectors are proposed for 2-D illumination applications that require highly uniform far-field illuminance, while ensuring maximal lighting efficiency and sharp angular cutoffs. The new designs derive from recent advances in nonimaging secondary concentrators for line-focus solar collectors. The light source is not treated as a single entity, but rather is divided into two or more separate adjoining sources. An asymmetric compound parabolic luminaire is then designed around each half-source. Attaining sharp cutoffs requires relatively large reflectors. However, severe truncation of the reflectors renders these devices as compact as many conventional luminaires, at the penalty of a small fraction of the radiation being emitted outside the nominal cutoff. The configurations that maximize the uniformity of far-field illuminance offer significant improvements in flux homogeneity relative to alternative designs to date.
Achieving uniform efficient illumination with multiple asymmetric compound parabolic luminaires

NASA Astrophysics Data System (ADS)

Gordon, Jeffrey M.; Kashin, Peter

1993-11-01

Luminaire designs based on multiple asymmetric nonimaging compound parabolic reflectors are proposed for 2-D illumination applications that require highly uniform far-field illuminance, while insuring maximal lighting efficiency and sharp angular cutoffs. The new designs derive from recent advances in nonimaging secondary concentrators for line-focus solar collectors. The light source is not treated as a single entity, but rather is divided into two or more separate adjoining sources. An asymmetric Compound Parabolic Luminaire is then designed around each half-source. Attaining sharp cutoffs requires relatively large reflectors. However, severe truncation of the reflectors renders these devices as compact as many conventional luminaires, at the penalty of a small fraction of the radiation being emitted outside the nominal cutoff. The configurations that maximize the uniformity of far-field illumination offer significant improvements in flux homogeneity relative to alternative designs to date.
U.S. Hail Frequency and the Global Wind Oscillation

NASA Astrophysics Data System (ADS)

Gensini, Vittorio A.; Allen, John T.

2018-02-01

Changes in Earth relative atmospheric angular momentum can be described by an index known as the Global Wind Oscillation. This global index accounts for changes in Earth's atmospheric budget of relative angular momentum through interactions of tropical convection anomalies, extratropical dynamics, and engagement of surface torques (e.g., friction and mountain). It is shown herein that U.S. hail events are more (less) likely to occur in low (high) atmospheric angular momentum base states when excluding weak Global Wind Oscillation days, with the strongest relationships found in the boreal spring and fall. Severe, significant severe, and giant hail events are more likely to occur during Global Wind Oscillation phases 8, 1, 2, and 3 during the peak of U.S. severe weather season. Lower frequencies of hail events are generally found in Global Wind Oscillation phases 4-7 but vary based on Global Wind Oscillation amplitude and month. In addition, probabilistic anomalies of atmospheric ingredients supportive of hail producing supercell thunderstorms closely mimic locations of reported hail frequency, helping to corroborate report results.
Well-posedness and Scattering for the Boltzmann Equations: Soft Potential with Cut-off

NASA Astrophysics Data System (ADS)

He, Lingbing; Jiang, Jin-Cheng

2017-07-01

We prove the global existence of the unique mild solution for the Cauchy problem of the cut-off Boltzmann equation for soft potential model γ =2-N with initial data small in L^N_{x,v} where N=2,3 is the dimension. The proof relies on the existing inhomogeneous Strichartz estimates for the kinetic equation by Ovcharov (SIAM J Math Anal 43(3):1282-1310, 2011) and convolution-like estimates for the gain term of the Boltzmann collision operator by Alonso et al. (Commun Math Phys 298:293-322, 2010). The global dynamics of the solution is also characterized by showing that the small global solution scatters with respect to the kinetic transport operator in L^N_{x,v}. Also the connection between function spaces and cut-off soft potential model -N<γ <2-N is characterized in the local well-posedness result for the Cauchy problem with large initial data.
Transverse vetoes with rapidity cutoff in SCET

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

Hornig, Andrew; Kang, Daekyoung; Makris, Yiannis

We consider di-jet production in hadron collisions where a transverse veto is imposed on radiation for (pseudo-)rapidities in the central region only, where this central region is defined with rapidity cutoff. For the case where the transverse measurement (e.g., transverse energy or min p T for jet veto) is parametrically larger relative to the typical transverse momentum beyond the cutoff, the cross section is insensitive to the cutoff parameter and is factorized in terms of collinear and soft degrees of freedom. The virtuality for these degrees of freedom is set by the transverse measurement, as in typical transverse-momentum dependent observablesmore » such as Drell-Yan, Higgs production, and the event shape broadening. This paper focuses on the other region, where the typical transverse momentum below and beyond the cutoff is of similar size. In this region the rapidity cutoff further resolves soft radiation into (u)soft and soft-collinear radiation with different rapidities but identical virtuality. This gives rise to rapidity logarithms of the rapidity cutoff parameter which we resum using renormalization group methods. We factorize the cross section in this region in terms of soft and collinear functions in the framework of soft-collinear effective theory, then further refactorize the soft function as a convolution of the (u)soft and soft-collinear functions. All these functions are calculated at one-loop order. As an example, we calculate a differential cross section for a specific partonic channel, qq ' → qq ' , for the jet shape angularities and show that the refactorization allows us to resum the rapidity logarithms and significantly reduce theoretical uncertainties in the jet shape spectrum.« less
Transverse vetoes with rapidity cutoff in SCET

DOE PAGES

Hornig, Andrew; Kang, Daekyoung; Makris, Yiannis; ...

2017-12-11

We consider di-jet production in hadron collisions where a transverse veto is imposed on radiation for (pseudo-)rapidities in the central region only, where this central region is defined with rapidity cutoff. For the case where the transverse measurement (e.g., transverse energy or min p T for jet veto) is parametrically larger relative to the typical transverse momentum beyond the cutoff, the cross section is insensitive to the cutoff parameter and is factorized in terms of collinear and soft degrees of freedom. The virtuality for these degrees of freedom is set by the transverse measurement, as in typical transverse-momentum dependent observablesmore » such as Drell-Yan, Higgs production, and the event shape broadening. This paper focuses on the other region, where the typical transverse momentum below and beyond the cutoff is of similar size. In this region the rapidity cutoff further resolves soft radiation into (u)soft and soft-collinear radiation with different rapidities but identical virtuality. This gives rise to rapidity logarithms of the rapidity cutoff parameter which we resum using renormalization group methods. We factorize the cross section in this region in terms of soft and collinear functions in the framework of soft-collinear effective theory, then further refactorize the soft function as a convolution of the (u)soft and soft-collinear functions. All these functions are calculated at one-loop order. As an example, we calculate a differential cross section for a specific partonic channel, qq ' → qq ' , for the jet shape angularities and show that the refactorization allows us to resum the rapidity logarithms and significantly reduce theoretical uncertainties in the jet shape spectrum.« less
Complementarity in the multiverse

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

Bousso, Raphael

2009-06-15

In the multiverse, as in AdS space, light cones relate bulk points to boundary scales. This holographic UV-IR connection defines a preferred global time cutoff that regulates the divergences of eternal inflation. An entirely different cutoff, the causal patch, arises in the holographic description of black holes. Remarkably, I find evidence that these two regulators define the same probability measure in the multiverse. Initial conditions for the causal patch are controlled by the late-time attractor regime of the global description.

Age, Gender and Ethnic Differences in Prevalence of Overweight and Obesity in Asian American College Students and Their Parents Using Different BMI Cutoffs

ERIC Educational Resources Information Center

Wang, Li Hui; Chen, Ying Chang; Ka Chung, Angela; Poon, George; Lew, Polong; Tam, Chick F.

2007-01-01

The objective was to determine if the WHO global BMI (kg/m[squared]) cutoffs for determining overweight and obesity in the general populations are appropriate for Asian populations and to consider whether population-specific cutoffs would be warranted. A nonrandomized biased sampling of 227 Asian Americans were composed of 149 college students,…
Possible connection between the location of the cutoff in the cosmic microwave background spectrum and the equation of state of dark energy.

PubMed

Enqvist, Kari; Sloth, Martin S

2004-11-26

We investigate a possible connection between the suppression of the power at low multipoles in the cosmic microwave background (CMB) spectrum and the late time acceleration. We show that, assuming a cosmic IR/UV duality between the UV cutoff and a global infrared cutoff given by the size of the future event horizon, the equation of state of the dark energy can be related to the apparent cutoff in the CMB spectrum. The present limits on the equation of state of dark energy are shown to imply an IR cutoff in the CMB multipole interval of 9>l>8.5.
A study of the effect of bulges on bar formation in disc galaxies

NASA Astrophysics Data System (ADS)

Kataria, Sandeep Kumar; Das, Mousumi

2018-04-01

We use N-body simulations of bar formation in isolated galaxies to study the effect of bulge mass and bulge concentration on bar formation. Bars are global disc instabilities that evolve by transferring angular momentum from the inner to outer discs and to the dark matter halo. It is well known that a massive spherical component such as halo in a disc galaxy can make it bar stable. In this study, we explore the effect of another spherical component, the bulge, on bar formation in disc galaxies. In our models, we vary both the bulge mass and concentration. We have used two sets of models: one that has a dense bulge and high surface density disc, and the other model has a less concentrated bulge and a lighter disc. In both models, we vary the bulge to disc mass fraction from 0 to 0.7. Simulations of both the models show that there is an upper cut-off in bulge-to-disc mass ratio Mb/Md above which bars cannot form; the cut-off is smaller for denser bulges (Mb/Md = 0.2) compared to less denser ones (Mb/Md = 0.5). We define a new criterion for bar formation in terms of the ratio of bulge to total radial force (Fb/Ftot) at the disc scale lengths above which bars cannot form. We find that if Fb/Ftot > 0.35, a disc is stable and a bar cannot form. Our results indicate that early-type disc galaxies can still form strong bars in spite of having massive bulges.
Neutrino Masses in the Landscape and Global-Local Dualities in Eternal Inflation

NASA Astrophysics Data System (ADS)

Mainemer Katz, Dan

In this dissertation we study two topics in Theoretical Cosmology: one more formal, the other more phenomenological. We work in the context of eternally inflating cosmologies. These arise in any fundamental theory that contains at least one stable or metastable de Sitter vacuum. Each topic is presented in a different chapter: Chapter 1 deals with the measure problem in eternal inflation. Global-local duality is the equivalence of seemingly different regulators in eternal inflation. For example, the light- cone time cutoff (a global measure, which regulates time) makes the same predictions as the causal patch (a local measure that cuts off space). We show that global-local duality is far more general. It rests on a redundancy inherent in any global cutoff: at late times, an attractor regime is reached, characterized by the unlimited exponential self-reproduction of a certain fundamental region of spacetime. An equivalent local cutoff can be obtained by restricting to this fundamental region. We derive local duals to several global cutoffs of interest. The New Scale Factor Cutoff is dual to the Short Fat Geodesic, a geodesic of fixed infinitesimal proper width. Vilenkin's CAH Cutoff is equivalent to the Hubbletube, whose width is proportional to the local Hubble volume. The famous youngness problem of the Proper Time Cutoff can be readily understood by considering its local dual, the Incredible Shrinking Geodesic. The chapter closely follows our paper. Chapter 2 deals with the question of whether neutrino masses could be anthropically explained. The sum of active neutrino masses is well constrained, 58 meV ≤ mupsilon [is approximately less than] 0.23 eV, but the origin of this scale is not well understood. Here we investigate the possibility that it arises by environmental selection in a large landscape of vacua. Earlier work had noted the detrimental effects of neutrinos on large scale structure. However, using Boltzmann codes to compute the smoothed density contrast on Mpc scales, we find that dark matter halos form abundantly for mupsilon [is approximately greater than] 10eV. This finding rules out an anthropic origin of mupsilon, unless a different catastrophic boundary can be identified. Here we argue that galaxy formation becomes inefficient for mupsilon [is approximately greater than] 10 eV. We show that in this regime, structure forms late and is dominated by cluster scales, as in a top-down scenario. This is catastrophic: baryonic gas will cool too slowly to form stars in an abundance comparable to our universe. With this novel cooling boundary, we find that the anthropic prediction for mupsilon agrees at better than 2sigma with current observational bounds. A degenerate hierarchy is mildly preferred. The chapter closely follows our paper.
The elevation, slope, and curvature spectra of a wind roughened sea surface

NASA Technical Reports Server (NTRS)

Pierson, W. J., Jr.; Stacy, R. A.

1973-01-01

The elevation, slope and curvature spectra are defined as a function of wave number and depend on the friction velocity. There are five wave number ranges of definition called the gravity wave-gravity equilibrium range, the isotropic turbulence range, the connecting range due to Leykin Rosenberg, the capillary range, and the viscous cutoff range. The higher wave number ranges are strongly wind speed dependent, and there is no equilibrium (or saturated) capillary range, at least for winds up to 30 meters/sec. Some properties of the angular variation of the spectra are also found. For high wave numbers, especially in the capillary range, the results are shown to be consistent with the Rayleigh-Rice backscattering theory (Bragg scattering), and certain properties of the angular variation are deduced from backscatter measurements.
Reduced bispectrum seeded by helical primordial magnetic fields

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

Hortúa, Héctor Javier; Castañeda, Leonardo, E-mail: hjhortuao@unal.edu.co, E-mail: lcastanedac@unal.edu.co

In this paper, we investigate the effects of helical primordial magnetic fields (PMFs) on the cosmic microwave background (CMB) reduced bispectrum. We derive the full three-point statistics of helical magnetic fields and numerically calculate the even contribution in the collinear configuration. We then numerically compute the CMB reduced bispectrum induced by passive and compensated PMF modes on large angular scales. There is a negative signal on the bispectrum due to the helical terms of the fields and we also observe that the biggest contribution to the bispectrum comes from the non-zero IR cut-off for causal fields, unlike the two-point correlationmore » case. For negative spectral indices, the reduced bispectrum is enhanced by the passive modes. This gives a lower value of the upper limit for the mean amplitude of the magnetic field on a given characteristic scale. However, high values of IR cut-off in the bispectrum, and the helical terms of the magnetic field relaxes this bound. This demonstrates the importance of the IR cut-off and helicity in the study of the nature of PMFs from CMB observations.« less
Global Plate Velocities from the Global Positioning System

NASA Technical Reports Server (NTRS)

Larson, Kristine M.; Freymueller, Jeffrey T.; Philipsen, Steven

1997-01-01

We have analyzed 204 days of Global Positioning System (GPS) data from the global GPS network spanning January 1991 through March 1996. On the basis of these GPS coordinate solutions, we have estimated velocities for 38 sites, mostly located on the interiors of the Africa, Antarctica, Australia, Eurasia, Nazca, North America, Pacific, and South America plates. The uncertainties of the horizontal velocity components range from 1.2 to 5.0 mm/yr. With the exception of sites on the Pacific and Nazca plates, the GPS velocities agree with absolute plate model predictions within 95% confidence. For most of the sites in North America, Antarctica, and Eurasia, the agreement is better than 2 mm/yr. We find no persuasive evidence for significant vertical motions (less than 3 standard deviations), except at four sites. Three of these four were sites constrained to geodetic reference frame velocities. The GPS velocities were then used to estimate angular velocities for eight tectonic plates. Absolute angular velocities derived from the GPS data agree with the no net rotation (NNR) NUVEL-1A model within 95% confidence except for the Pacific plate. Our pole of rotation for the Pacific plate lies 11.5 deg west of the NNR NUVEL-1A pole, with an angular speed 10% faster. Our relative angular velocities agree with NUVEL-1A except for some involving the Pacific plate. While our Pacific-North America angular velocity differs significantly from NUVEL-1A, our model and NUVEL-1A predict very small differences in relative motion along the Pacific-North America plate boundary itself. Our Pacific-Australia and Pacific- Eurasia angular velocities are significantly faster than NUVEL-1A, predicting more rapid convergence at these two plate boundaries. Along the East Pacific Pise, our Pacific-Nazca angular velocity agrees in both rate and azimuth with NUVFL-1A.
High Angular Resolution Imaging of Solar Radio Bursts from the Lunar Surface

NASA Technical Reports Server (NTRS)

MacDowall, Robert J.; Lazio, Joseph; Bale, Stuart; Burns, Jack O.; Farrell, William M.; Gopalswamy, Nat; Jones, Dayton L.; Kasper, Justin Christophe; Weiler, Kurt

2012-01-01

Locating low frequency radio observatories on the lunar surface has a number of advantages, including positional stability and a very low ionospheric radio cutoff. Here, we describe the Radio Observatory on the lunar Surface for Solar studies (ROLSS), a concept for a low frequency, radio imaging interferometric array designed to study particle acceleration in the corona and inner heliosphere. ROLSS would be deployed during an early lunar sortie or by a robotic rover as part of an unmanned landing. The preferred site is on the lunar near side to simplify the data downlink to Earth. The prime science mission is to image type II and type III solar radio bursts with the aim of determining the sites at and mechanisms by which the radiating particles are accelerated. Secondary science goals include constraining the density of the lunar ionosphere by measuring the low radio frequency cutoff of the solar radio emissions or background galactic radio emission, measuring the flux, particle mass, and arrival direction of interplanetary and interstellar dust, and constraining the low energy electron population in astrophysical sources. Furthermore, ROLSS serves a pathfinder function for larger lunar radio arrays. Key design requirements on ROLSS include the operational frequency and angular resolution. The electron densities in the solar corona and inner heliosphere are such that the relevant emission occurs below 10 M Hz, essentially unobservable from Earth's surface due to the terrestrial ionospheric cutoff. Resolving the potential sites of particle acceleration requires an instrument with an angular resolution of at least 2 deg at 10 MHz, equivalent to a linear array size of approximately one kilometer. The major components of the ROLSS array are 3 antenna arms, each of 500 m length, arranged in a Y formation, with a central electronics package (CEP) at their intersection. Each antenna arm is a linear strip of polyimide film (e.g., Kapton(TradeMark)) on which 16 single polarization dipole antennas are located by depositing a conductor (e.g., silver). The arms also contain transmission lines for carrying the radio signals from the science antennas to the CEP. Operations would consist of data acquisition during the lunar day, with data downlinks to Earth one or more times every 24 hours.
Systematic approach to cutoff frequency selection in continuous-wave electron paramagnetic resonance imaging

NASA Astrophysics Data System (ADS)

Hirata, Hiroshi; Itoh, Toshiharu; Hosokawa, Kouichi; Deng, Yuanmu; Susaki, Hitoshi

2005-08-01

This article describes a systematic method for determining the cutoff frequency of the low-pass window function that is used for deconvolution in two-dimensional continuous-wave electron paramagnetic resonance (EPR) imaging. An evaluation function for the criterion used to select the cutoff frequency is proposed, and is the product of the effective width of the point spread function for a localized point signal and the noise amplitude of a resultant EPR image. The present method was applied to EPR imaging for a phantom, and the result of cutoff frequency selection was compared with that based on a previously reported method for the same projection data set. The evaluation function has a global minimum point that gives the appropriate cutoff frequency. Images with reasonably good resolution and noise suppression can be obtained from projections with an automatically selected cutoff frequency based on the present method.
New results on the generation of broadband electrostatic waves in the magnetotail

NASA Technical Reports Server (NTRS)

Grabbe, C. L.

1985-01-01

The theory of the generation of broadband electrostatic noise (BEN) in the magnetotail is extended through numerical solution of the dispersion relation under conditions that exist in the plasma sheet boundary layer. It is found that the low-frequency portion of the spectrum has a broad angular spectrum but a fairly sharp peak near 75 deg with respect to the magnetic field, while the high-frequency portion has a narrower angular spectrum that is strongly concentrated along the magnetic field line. These results are in excellent agreement with observations of the broadband wave spectrum and a recent measurement of the propagation direction. The effect of a second cold component of electrons is analyzed, and it is found that it can increase the upper cutoff frequency of BEN to the observed value at about the plasma frequency.
Unravelling the Drivers of Chute Cutoff and the Commonality of Oxbow Production

NASA Astrophysics Data System (ADS)

Constantine, J. A.; Edmonds, D. A.; David, S.

2017-12-01

Chute cutoff is the principal means of channel shortening along steep, sparsely vegetated, or perturbed meandering river floodplains. Although flood waters are capable of unravelling the floodplain in a variety of ways, only a small number of mechanisms of chute cutoff have been observed in nature, each with seemingly different controls on their occurrence. The complexity of these controls partly explains the difficulty of deterministically incorporating chute cutoff into channel evolution models. Despite the challenges, recent field observations have allowed us not only to identify particular mechanisms but also to highlight first-order controls. We provide a summary of these findings and describe the processes that drive the various mechanisms of cutoff and their resulting oxbow lakes. For example, many agricultural floodplains show evidence of pervasive gully incision as a precursor to chute cutoff. And perhaps surprising given the diversity of cutoff mechanisms, oxbows globally share characteristic dimensions that are a function of the sinuosity and width of the rivers from which they are derived. Our results suggest that, in spite of the many processes involved, aspects of the mechanisms of chute cutoff can be generalised, providing a means for improving cutoff prediction and for assessing the impacts of cutoffs on the meandering river floodplain.
D = 5 Einstein-Maxwell-Chern-Simons black holes.

PubMed

Kunz, Jutta; Navarro-Lérida, Francisco

2006-03-03

Five-dimensional Einstein-Maxwell-Chern-Simons theory with a Chern-Simons coefficient lambda = 1 has supersymmetric black holes with a vanishing horizon angular velocity but finite angular momentum. Here supersymmetry is associated with a borderline between stability and instability, since for lambda > 1 a rotational instability arises, where counterrotating black holes appear, whose horizon rotates in the opposite sense to the angular momentum. For lambda > 2 black holes are no longer uniquely characterized by their global charges, and rotating black holes with vanishing angular momentum appear.
Substrate strain induced interaction of adatoms on W (110)

NASA Astrophysics Data System (ADS)

Kappus, W.

1980-09-01

The interaction of adatoms due to elastic strains created in an elastically isotropic substrate is investigated. For cases where the adatoms occupy sites with low symmetry, an angular dependent interaction results which falls off as s-3 at large distances. An exact expression is given for the long range interaction in terms of an anisotropy parameter of the force dipole tensor. The short range interaction is calculated by introducing a smooth cutoff. Interactions of adatoms on near neighbour sites on W (110) are given.
Emergency Coagulation Assessment During Treatment With Direct Oral Anticoagulants: Limitations and Solutions.

PubMed

Ebner, Matthias; Birschmann, Ingvild; Peter, Andreas; Härtig, Florian; Spencer, Charlotte; Kuhn, Joachim; Blumenstock, Gunnar; Zuern, Christine S; Ziemann, Ulf; Poli, Sven

2017-09-01

In patients receiving direct oral anticoagulants (DOACs), emergency treatment like thrombolysis for acute ischemic stroke is complicated by insufficient availability of DOAC-specific coagulation tests. Conflicting recommendations have been published concerning the use of global coagulation assays for ruling out relevant DOAC-induced anticoagulation. Four hundred eighty-one samples from 96 DOAC-treated patients were tested using prothrombin time (PT), activated partial thromboplastin time (aPTT) and thrombin time (TT), DOAC-specific assays (anti-Xa activity, diluted TT), and liquid chromatography-tandem mass spectrometry. Sensitivity and specificity of test results to identify DOAC concentrations <30 ng/mL were calculated. Receiver operating characteristic analyses were used to define reagent-specific cutoff values. Normal PT and aPTT provide insufficient specificity to safely identify DOAC concentrations <30 ng/mL (rivaroxaban/PT: specificity, 77%/sensitivity, 94%; apixaban/PT: specificity, 13%/sensitivity, 94%, dabigatran/aPTT: specificity, 49%/sensitivity, 91%). Normal TT was 100% specific for dabigatran, but sensitivity was 26%. In contrast, reagent-specific PT and aPTT cutoffs provided >95% specificity and a specific TT cutoff enhanced sensitivity for dabigatran to 84%. For apixaban, no cutoffs could be established. Even if highly DOAC-reactive reagents are used, normal results of global coagulation tests are not suited to guide emergency treatment: whereas normal PT and aPTT lack specificity to rule out DOAC-induced anticoagulation, the low sensitivity of normal TT excludes the majority of eligible patients from treatment. However, reagent-specific cutoffs for global coagulation tests ensure high specificity and optimize sensitivity for safe emergency decision making in rivaroxaban- and dabigatran-treated patients. URL: http://www.clinicaltrials.gov. Unique identifiers: NCT02371044 and NCT02371070. © 2017 American Heart Association, Inc.
Dibaryons with Strangeness in Quark Models

NASA Astrophysics Data System (ADS)

Chen, Mei; Gong, Fang; Huang, Hongxia; Ping, Jialun

The extended quark delocalization color screening model, which incorporates Goldstone-boson-exchange with soft cutoff, and chiral quark model are employed to do a systematic dynamical calculation of six-quark systems with strangeness. The two models give similar results, although they have different attraction mechanisms. Comparing with the previous calculation of the extended quark delocalization color screening model, in which the Goldstone-bosons are introduced with hard cutoff, the present calculation obtains a little large binding energies for most of the states. However, the conclusions are the same. The calculations show that NΩ state with IJ = 1/2, 2 is a good dibaryon candidate with narrow width, and ΩΩ state with IJ = 00 is a stable dibaryon against the strong interaction. The calculations also reveal several other possible dibaryon candidates with high angular momentum, ΔΣ*(1/2, 3), ΔΞ*(1, 3), etc. These states may have too wide width to be observed experimentally.
2016 Resembles Past Global Dust Storm Years on Mars

NASA Image and Video Library

2016-10-05

This graphic indicates a similarity between 2016 (dark blue line) and five past years in which Mars has experienced a global dust storm (orange lines and band), compared to years with no global dust storm (blue-green lines and band). The arrow nearly midway across in the dark blue line indicates the Mars time of year in late September 2016. A key factor in the graph is the orbital angular momentum of Mars, which would be steady in a system of only one planet orbiting the sun, but varies due to relatively small effects of having other planets in the solar system. The horizontal scale is time of year on Mars, starting at left with the planet's farthest distance from the sun in each orbit. This point in the Mars year, called "Mars aphelion," corresponds to late autumn in the southern hemisphere. Numeric values on the horizontal axis are in Earth years; each Mars year lasts for about 1.9 Earth years. The vertical scale bar at left applies only to the black-line curve on the graph. The amount of solar energy entering Mars' atmosphere (in watts per square meter) peaks at the time of year when Mars is closest to the sun, corresponding to late spring in the southern hemisphere. The duration of Mars' dust storm season, as indicated, brackets the time of maximum solar input to the atmosphere. The scale bar at right, for orbital angular momentum, applies to the blue, brown and blue-green curves on the graph. The values are based on mass, velocity and distance from the gravitational center of the solar system. Additional information on the units is in a 2015 paper in the journal Icarus, from which this graph is derived. The band shaded in orange is superimposed on the curves of angular momentum for five Mars years that were accompanied by global dust storms in 1956, 1971, 1982, 1994 and 2007. Brown diamond symbols on the curves for these years in indicate the times when the global storms began. The band shaded blue-green lies atop angular momentum curves for six years when no global dust storms occurred: 1939, 1975, 1988, 1998, 2000 and 2011. Note that in 2016, as in the pattern of curves for years with global dust storms, the start of the dust storm season corresponded to a period of increasing orbital angular momentum. In years with no global storm, angular momentum was declining at that point. Observations of whether dust from regional storms on Mars spreads globally in late 2016 or early 2017 will determine whether this correspondence holds up for the current Mars year. http://photojournal.jpl.nasa.gov/catalog/PIA20855
Angular default mode network connectivity across working memory load.

PubMed

Vatansever, D; Manktelow, A E; Sahakian, B J; Menon, D K; Stamatakis, E A

2017-01-01

Initially identified during no-task, baseline conditions, it has now been suggested that the default mode network (DMN) engages during a variety of working memory paradigms through its flexible interactions with other large-scale brain networks. Nevertheless, its contribution to whole-brain connectivity dynamics across increasing working memory load has not been explicitly assessed. The aim of our study was to determine which DMN hubs relate to working memory task performance during an fMRI-based n-back paradigm with parametric increases in difficulty. Using a voxel-wise metric, termed the intrinsic connectivity contrast (ICC), we found that the bilateral angular gyri (core DMN hubs) displayed the greatest change in global connectivity across three levels of n-back task load. Subsequent seed-based functional connectivity analysis revealed that the angular DMN regions robustly interact with other large-scale brain networks, suggesting a potential involvement in the global integration of information. Further support for this hypothesis comes from the significant correlations we found between angular gyri connectivity and reaction times to correct responses. The implication from our study is that the DMN is actively involved during the n-back task and thus plays an important role related to working memory, with its core angular regions contributing to the changes in global brain connectivity in response to increasing environmental demands. Hum Brain Mapp 38:41-52, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.
Measurement of angular velocity in the perception of rotation.

PubMed

Barraza, José F; Grzywacz, Norberto M

2002-09-01

Humans are sensitive to the parameters of translational motion, namely, direction and speed. At the same time, people have special mechanisms to deal with more complex motions, such as rotations and expansions. One wonders whether people may also be sensitive to the parameters of these complex motions. Here, we report on a series of experiments that explore whether human subjects can use angular velocity to evaluate how fast a rotational motion is. In four experiments, subjects were required to perform a task of speed-of-rotation discrimination by comparing two annuli of different radii in a temporal 2AFC paradigm. Results showed that humans could rely on a sensitive measurement of angular velocity to perform this discrimination task. This was especially true when the quality of the rotational signal was high (given by the number of dots composing the annulus). When the signal quality decreased, a bias towards linear velocity of 5-80% appeared, suggesting the existence of separate mechanisms for angular and linear velocity. This bias was independent from the reference radius. Finally, we asked whether the measurement of angular velocity required a rigid rotation, that is, whether the visual system makes only one global estimate of angular velocity. For this purpose, a random-dot disk was built such that all the dots were rotating with the same tangential speed, irrespectively of radius. Results showed that subjects do not estimate a unique global angular velocity, but that they perceive a non-rigid disk, with angular velocity falling inversely proportionally with radius.
Search for new physics in dijet angular distributions using proton-proton collisions at $$\\sqrt{s}=$$ 13 TeV and constraints on dark matter and other models

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

Sirunyan, Albert M; et al.

A search is presented for physics beyond the standard model, based on measurements of dijet angular distributions in proton-proton collisions atmore » $$\\sqrt{s}=$$ 13 TeV. The data collected with the CMS detector at the LHC correspond to an integrated luminosity of 35.9 fb$$^{-1}$$. The observed distributions are found to be in agreement with predictions from perturbative quantum chromodynamics that include electroweak corrections, and constraints are placed on models containing quark contact interactions, extra spatial dimensions, quantum black holes, or dark matter. In a benchmark model where only left-handed quarks participate, contact interactions are excluded at the 95% confidence level up to a scale of 12.8 or 17.5 TeV, for destructive or constructive interference, respectively. The most stringent lower limits to date are set on the ultraviolet cutoff in the Arkani-Hamed-Dimopoulos-Dvali model of extra dimensions. In the Giudice-Rattazzi-Wells convention, the cutoff scale is excluded up to 10.1 TeV. The production of quantum black holes is excluded for masses below 5.9 and 8.2 TeV, depending on the model. For the first time, lower limits between 2.0 and 4.6 TeV are set on the mass of a dark matter mediator for (axial-)vector mediators, for the universal quark coupling $$g_\\mathrm{q}\\geq$$ 1.« less
Diagnostic power of longitudinal strain at rest for the detection of obstructive coronary artery disease in patients with type 2 diabetes mellitus.

PubMed

Zuo, Houjuan; Yan, Jiangtao; Zeng, Hesong; Li, Wenyu; Li, Pengcheng; Liu, Zhengxiang; Cui, Guanglin; Lv, Jiagao; Wang, Daowen; Wang, Hong

2015-01-01

Global longitudinal strain (GLS) measured by 2-D speckle-tracking echocardiography (2-D STE) at rest has been recognized as a sensitive parameter in the detection of significant coronary artery disease (CAD). However, the diagnostic power of 2-D STE in the detection of significant CAD in patients with diabetes mellitus is unknown. Two-dimensional STE features were studied in total of 143 consecutive patients who underwent echocardiography and coronary angiography. Left ventricular global and segmental peak systolic longitudinal strains (PSLSs) were quantified by speckle-tracking imaging. In the presence of obstructive CAD (defined as stenosis ≥75%), global PSLS was significantly lower in patients with diabetes mellitus than in patients without (16.65 ± 2.29% vs. 17.32 ± 2.27%, p < 0.05). Receiver operating characteristic analysis revealed that global PSLS could effectively detect obstructive CAD in patients without diabetes mellitus (cutoff value: -18.35%, sensitivity: 78.8%, specificity: 77.5%). However, global PSLS could detect obstructive CAD in diabetic patients at a lower cutoff value with inadequate sensitivity and specificity (cutoff value: -17.15%; sensitivity: 61.1%, specificity: 52.9%). In addition, the results for segmental PSLS were similar to those for global PSLS. In conclusion, global and segmental PSLSs at rest were significantly lower in patients with both obstructive CAD and diabetes mellitus than in patients with obstructive CAD only; thus, PSLSs at rest might not be a useful parameter in the detection of obstructive CAD in patients with diabetes mellitus. Copyright © 2015 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Nonlinear management of the angular momentum of soliton clusters: Theory and experiment

NASA Astrophysics Data System (ADS)

Fratalocchi, Andrea; Piccardi, Armando; Peccianti, Marco; Assanto, Gaetano

2007-06-01

We demonstrate, both theoretically and experimentally, how to acquire nonlinear control over the angular momentum of a cluster of solitary waves. Our results, stemming from a universal theoretical model, show that the angular momentum can be adjusted by acting on the global energy input in the system. The phenomenon is experimentally ascertained in nematic liquid crystals by observing a power-dependent rotation of a two-soliton ensemble.
Full-wave feasibility study of anti-radar diagnostic of magnetic field based on O-X mode conversion and oblique reflectometry imaging

DOE PAGES

Meneghini, Orso; Volpe, Francesco A.

2016-08-19

An innovative millimeter wave diagnostic is proposed to measure the local magnetic field and edge current as a function of the minor radius in the tokamak pedestal region. The idea is to identify the direction of minimum reflectivity at the O-mode cutoff layer. Correspondingly, the transmissivity due to O-X mode conversion is maximum. That direction, and the angular map of reflectivity around it, contain information on the magnetic field vector B at the cutoff layer. By probing the plasma with different wave frequencies it provides the radial profile of B. Full-wave finite-element simulations are presented here in 2D slab geometry.more » Modeling confirms the existence of a minimum in reflectivity that depends on the magnetic field at the cutoff, as expected from mode conversion physics, giving confidence in the feasibility of the diagnostic. We proposed an reflectometric approach in order to yield superior signal-to-noise ratio and to access wider ranges of density and magnetic field, compared with related radiometric techniques that require the plasma to emit Electron Bernstein Waves. Due to computational limitations, frequencies of 10-20 GHz were considered in this initial study. Furthermore, frequencies above the edge electron-cyclotron frequency (f >28 GHz here) would be preferable for the experiment, because the upper hybrid resonance and right cutoff would lie in the plasma, and would help separate the O-mode of interest from spurious X-waves.« less
Full-wave feasibility study of anti-radar diagnostic of magnetic field based on O-X mode conversion and oblique reflectometry imaging

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

Meneghini, Orso; Volpe, Francesco A., E-mail: fvolpe@columbia.edu

An innovative millimeter wave diagnostic is proposed to measure the local magnetic field and edge current as a function of the minor radius in the tokamak pedestal region. The idea is to identify the direction of minimum reflectivity at the O-mode cutoff layer. Correspondingly, the transmissivity due to O-X mode conversion is maximum. That direction, and the angular map of reflectivity around it, contains information on the magnetic field vector B at the cutoff layer. Probing the plasma with different wave frequencies provides the radial profile of B. Full-wave finite-element simulations are presented here in 2D slab geometry. Modeling confirmsmore » the existence of a minimum in reflectivity that depends on the magnetic field at the cutoff, as expected from mode conversion physics, giving confidence in the feasibility of the diagnostic. The proposed reflectometric approach is expected to yield superior signal-to-noise ratio and to access wider ranges of density and magnetic field, compared with related radiometric techniques that require the plasma to emit electron Bernstein waves. Due to computational limitations, frequencies of 10-20 GHz were considered in this initial study. Frequencies above the edge electron-cyclotron frequency (f > 28 GHz here) would be preferable for the experiment, because the upper hybrid resonance and right cutoff would lie in the plasma, and would help separate the O-mode of interest from spurious X-waves.« less
The rigid shell component for superrotation in planetary atmospheres: Angular momentum budget, mechanical analog and simulation of the spin up process

NASA Technical Reports Server (NTRS)

Mayr, H. G.; Harris, I.

1981-01-01

An analysis of superrotation in the atmosphere of planets, with rotation axis perpendicular to the orbital plane is presented. As the atmosphere expands, Hadley cells develop producing a redistribution of mass and angular momentum. A three dimensional thermally driven zonally symmetric spectral model and Laplace transformation simulate the time evolution of a fluid leading from corotation under globally uniform heating to superrotation under globally nonuniform heating. For high viscosities the rigid shell component of atmospheric superrotation can be understood in analogy with a pirouette. During spin up angular momentum is transferred to the planet. For low iscosities, the process is reversed. A tendency toward geostrophy, combined with increase of surface pressure toward the poles (due to meridional mass transport), induces the atmosphere to subrotate temporarily at lower altitudes. Resultant viscous shear near the surface permits angular momentum to flow from the planet into the atmosphere propagating upwards to produce high altitude superrotation rates.
Phase transitions triggered by quantum fluctuations in the inflationary universe

NASA Technical Reports Server (NTRS)

Nagasawa, Michiyasu; Yokoyama, Junichi

1991-01-01

The dynamics of a second-order phase transition during inflation, which is induced by time-variation of spacetime curvature, is studied as a natural mechanism to produce topological defects of typical grand unification scales such as cosmic strings or global textures. It is shown that their distribution is almost scale-invariant with small- and large-scale cutoffs. Also discussed is how these cutoffs are given.
Radon detection in conical diffusion chambers: Monte Carlo calculations and experiment

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

Rickards, J.; Golzarri, J. I.; Espinosa, G., E-mail: espinosa@fisica.unam.mx

2015-07-23

The operation of radon detection diffusion chambers of truncated conical shape was studied using Monte Carlo calculations. The efficiency was studied for alpha particles generated randomly in the volume of the chamber, and progeny generated randomly on the interior surface, which reach track detectors placed in different positions within the chamber. Incidence angular distributions, incidence energy spectra and path length distributions are calculated. Cases studied include different positions of the detector within the chamber, varying atmospheric pressure, and introducing a cutoff incidence angle and energy.
Measurement of asthma control according to global initiative for asthma guidelines: a comparison with the asthma control questionnaire

PubMed Central

2012-01-01

Introduction Asthma Control Questionnaire (ACQ) is a validated tool to measure asthma control. Cut-off points that best discriminate “well-controlled” or “not well-controlled” asthma have been suggested from the analysis of a large randomized clinical trial but they may not be adequate for daily clinical practice. Aims To establish cut-off points of the ACQ that best discriminate the level of control according to Global Initiative for Asthma (GINA) 2006 guidelines in patients with asthma managed at Allergology and Pulmonology Departments as well as Primary Care Centers in Spain. Patients and methods An epidemiological descriptive study, with prospective data collection. Asthma control following GINA-2006 classification and 7-item ACQ was assessed. The study population was split in two parts: 2/3 for finding the cut-off points (development population) and 1/3 for validating the results (validation population). Results A total of 1,363 stable asthmatic patients were included (mean age 38 ± 14 years, 60.3% women; 69.1% non-smokers). Patient classification according to GINA-defined asthma control was: controlled 13.6%, partially controlled 34.2%, and uncontrolled 52.3%. The ACQ cut-off points that better agreed with GINA-defined asthma control categories were calculated using receiver operating curves (ROC). The analysis showed that ACQ < 0.5 was the optimal cut-off point for “controlled asthma” (sensitivity 74.1%, specificity 77.5%) and 1.00 for “uncontrolled asthma” (sensitivity 73%, specificity 88.2%). Kappa index between GINA categories and ACQ was 0.62 (p < 0.001). Conclusion The ACQ cut-off points associated with GINA-defined asthma control in a real-life setting were <0.5 for controlled asthma and ≥1 for uncontrolled asthma. PMID:22726416
Measurement of asthma control according to Global Initiative for Asthma guidelines: a comparison with the Asthma Control Questionnaire.

PubMed

Olaguibel, José María; Quirce, Santiago; Juliá, Berta; Fernández, Cristina; Fortuna, Ana María; Molina, Jesús; Plaza, Vicente

2012-06-22

Asthma Control Questionnaire (ACQ) is a validated tool to measure asthma control. Cut-off points that best discriminate "well-controlled" or "not well-controlled" asthma have been suggested from the analysis of a large randomized clinical trial but they may not be adequate for daily clinical practice. To establish cut-off points of the ACQ that best discriminate the level of control according to Global Initiative for Asthma (GINA) 2006 guidelines in patients with asthma managed at Allergology and Pulmonology Departments as well as Primary Care Centers in Spain. An epidemiological descriptive study, with prospective data collection. Asthma control following GINA-2006 classification and 7-item ACQ was assessed. The study population was split in two parts: 2/3 for finding the cut-off points (development population) and 1/3 for validating the results (validation population). A total of 1,363 stable asthmatic patients were included (mean age 38 ± 14 years, 60.3% women; 69.1% non-smokers). Patient classification according to GINA-defined asthma control was: controlled 13.6%, partially controlled 34.2%, and uncontrolled 52.3%. The ACQ cut-off points that better agreed with GINA-defined asthma control categories were calculated using receiver operating curves (ROC). The analysis showed that ACQ < 0.5 was the optimal cut-off point for "controlled asthma" (sensitivity 74.1%, specificity 77.5%) and 1.00 for "uncontrolled asthma" (sensitivity 73%, specificity 88.2%). Kappa index between GINA categories and ACQ was 0.62 (p < 0.001). The ACQ cut-off points associated with GINA-defined asthma control in a real-life setting were <0.5 for controlled asthma and ≥1 for uncontrolled asthma.
Controls on cutoff formation along a tropical meandering river in the Amazon Basin

NASA Astrophysics Data System (ADS)

Ahmed, J.; Constantine, J. A.

2016-12-01

The termination of meander bends is an inherent part of the evolution of meandering rivers. Cutoffs are produced by one of two mechanisms: neck cutoffs occur when two adjacent meanders converge, while chute cutoffs are generated by flood-driven floodplain incision, resulting in a shorter, steeper channel path. Here we use an annually-resolved record of Landsat imagery, coupled with daily discharge data to assess the role of high-magnitude discharges (Q ≥ QBF) on cutoff formation along the Rio Beni, Bolivia. Our results suggest that despite numerous above-bankfull events, the dominant cutoff mechanism operating on the Beni is neck cutoff. Evaluating the formation of these cutoffs reveals that migration rates accelerate during years of high discharge, and eventually cause the migrating bends to breach. The density of floodplain vegetation and the medium into which the channel migrated was also responsible for the patterns of cutoff documented along this river. The presence of existing floodplain channels permitted the river to divert its flow along shorter courses thereby facilitating cutoff, and limiting sinuosity growth. Understanding the long-term evolution of meandering channels is important since their morphodynamics are responsible for the creation of highly biodiverse riparian habitats, as well as the store and release of alluvial material. Moreover, the interactions between discharge and the channel-floodplain system are integral for the functioning and long-term evolution of these landscapes, particularly in the face of global climate change.
Maximal power output by solar cells with angular confinement.

PubMed

Höhn, Oliver; Kraus, Tobias; Bauhuis, Gerard; Schwarz, Ulrich T; Bläsi, Benedikt

2014-05-05

Angularly selective filters can increase the efficiency of radiatively limited solar cells. A restriction of the acceptance angle is linked to the kind of utilizable solar spectrum (global or direct radiation). This has to be considered when calculating the potential enhancement of both the efficiency and the power output. In this paper, different concepts to realize angularly selective filters are compared regarding their limits for efficiency and power output per unit area. First experimental results of a promising system based on a thin-film filter as the angularly selective element are given to demonstrate the practical relevance of such systems.
Broadband spatial optical filtering with a volume Bragg grating and a blazed grating pair

NASA Astrophysics Data System (ADS)

Chen, Guanjin; Sun, Xiaojie; Yuan, Xiao; Zhang, Guiju

2017-10-01

A broadband spatial optical filtering system is presented in this paper, which is composed of a Volume Bragg Grating (VBG) and a blazed grating pair. The diffraction efficiency and filtering properties are calculated and simulated by using Fourier diffraction analysis and Coupled Wave Theory. A blazed grating pair and VBG structures are designed and optimized in our simulation. The diffraction efficiency of filtering system shows more than 77.2% during the wavelength period from 953nm to 1153nm, especially 84.1% at the center wavelength. The beam quality is described with near-field modulation (M) and contrast ratio (C). The M of filtering beam are 1.44, 1.49 and 1.55, respectively and the C of filtering beam are 10.1%, 10.2% and 10.5% , respectively and the beam intensity distribution is great improved. The cut-off frequencies of three filtering systems are 1.57mm-1 , 2.06 mm-1 and 2.38 mm-1 , respectively from power spectral density (PSD) curve. It's clear that the cut-off frequency of filtering system is closely related to the angular selectivity of VBG, and the value of cut-off frequency is decided by VBG's Half Width at First Zero (HWFZ) and center wavelength.
Human Sensibility Ergonomics Approach to Vehicle Simulator Based on Dynamics

NASA Astrophysics Data System (ADS)

Son, Kwon; Choi, Kyung-Hyun; Yoon, Ji-Sup

Simulators have been used to evaluate drivers' reactions to various transportation products. Most research, however, has concentrated on their technical performance. This paper considers driver's motion perception on a vehicle simulator through the analysis of human sensibility ergonomics. A sensibility ergonomic method is proposed in order to improve the reliability of vehicle simulators. A simulator in a passenger vehicle consists of three main modules such as vehicle dynamics, virtual environment, and motion representation modules. To evaluate drivers' feedback, human perceptions are categorized into a set verbal expressions collected and investigated to find the most appropriate ones for translation and angular accelerations of the simulator. The cut-off frequency of the washout filter in the representation module is selected as one sensibility factor. Sensibility experiments were carried out to find a correlation between the expressions and the cut-off frequency of the filter. This study suggests a methodology to obtain an ergonomic database that can be applied to the sensibility evaluation of dynamic simulators.
Radius anomaly in the diffraction model for heavy-ion elastic scattering

NASA Astrophysics Data System (ADS)

Pandey, L. N.; Mukherjee, S. N.

1984-04-01

The elastic scattering of heavy ions, 20Ne on 208Pb, 20Ne on 235U, 84Kr on 208Pb, and 84Kr on 232Th, is examined within the framework of Frahn's diffraction model. An analysis of the experiment using the "quarter point recipe" of the expected Fresnel cross sections yields a larger radius for 208Pb than the radii for 235U and 232Th. It is shown that inclusion of the nuclear deformation in the model removes the above anomaly in the radii, and the assumption of smooth cutoff of the angular momentum simultaneously leads to a better fit to elastic scattering data, compared to those obtained by the earlier workers on the assumption of sharp cutoff. [NUCLEAR REACTIONS Elastic scattering, 20Ne+208Pb (161.2 MeV), 20Ne+235U (175 MeV), 84Kr+208Pb (500 MeV), 84Kr+232Th (500 MeV), diffraction model, nuclear deformation.
Assessment of the Global and Regional Land Hydrosphere and Its Impact on the Balance of the Geophysical Excitation Function of Polar Motion

NASA Astrophysics Data System (ADS)

Wińska, Małgorzata; Nastula, Jolanta; Kołaczek, Barbara

2016-02-01

The impact of continental hydrological loading from land water, snow and ice on polar motion excitation, calculated as hydrological angular momentum (HAM), is difficult to estimate, and not as much is known about it as about atmospheric angular momentum (AAM) and oceanic angular momentum (OAM). In this paper, regional hydrological excitations to polar motion are investigated using monthly terrestrial water storage data derived from the Gravity Recovery and Climate Experiment (GRACE) mission and from the five models of land hydrology. The results show that the areas where the variance shows large variability are similar for the different models of land hydrology and for the GRACE data. Areas which have a small amplitude on the maps make an important contribution to the global hydrological excitation function of polar motion. The comparison of geodetic residuals and global hydrological excitation functions of polar motion shows that none of the hydrological excitation has enough energy to significantly improve the agreement between the observed geodetic excitation and geophysical ones.
Variations in atmospheric angular momentum and the length of day

NASA Technical Reports Server (NTRS)

Rosen, R. D.; Salstein, D. A.

1982-01-01

Six years of twice daily global analyses were used to create and study a lengthy time series of high temporal resolution angular momentum values. Changes in these atmospheric values were compared to independently determined charges in the rotation rate of the solid Earth. Finally, the atmospheric data was examined in more detail to determine the time and space scales on which variations in momentum occur within the atmosphere and which regions are contributing most to the changes found in the global integral. The data and techniques used to derive the time series of momentum values are described.
Climatological Features of Cutoff Low Systems in the Northern Hemisphere.

NASA Astrophysics Data System (ADS)

Nieto, Raquel; Gimeno, Luis; de La Torre, Laura; Ribera, Pedro; Gallego, David; García-Herrera, Ricardo; Agustín García, José; Nuñez, Marcelino; Redaño, Angel; Lorente, Jerónimo

2005-08-01

This study presents the first multidecadal climatology of cutoff low systems in the Northern Hemisphere. The climatology was constructed by using 41 yr (1958-98) of NCEP-NCAR reanalysis data and identifying cutoff lows by means of an objective method based on imposing the three main physical characteristics of the conceptual model of cutoff low (the 200-hPa geopotential minimum, cutoff circulation, and the specific structure of both equivalent thickness and thermal front parameter fields).Several results were confirmed and climatologically validated: 1) the existence of three preferred areas of cutoff low occurrence (the first one extends through southern Europe and the eastern Atlantic coast, the second one is the eastern North Pacific, and the third one is the northern China-Siberian region extending to the northwestern Pacific coast; the European area is the most favored region); 2) the known seasonal cycle, with cutoff lows forming much more frequently in summer than in winter; 3) the short lifetime of cutoff lows, most cutoff lows lasted 2-3 days and very few lasted more than 5 days; and 4) the mobility of the system, with few cutoff lows being stationary. Furthermore, the long study period has made it possible (i) to find a bimodal distribution in the geographical density of cutoff lows for the European sector in all the seasons (with the exception of winter), a summer displacement to the ocean in the American region, and a summer extension to the continent in the Asian region, and (ii) to detect northward and westward motion especially in the transitions from the second to third day of occurrence and from the third to fourth day of occurrence.The long-term cutoff low database built in this study is appropriate to study the interannual variability of cutoff low occurrence and the links between cutoff lows and jet stream systems, blocking, or major modes of climate variability as well as the global importance of cutoff low in the stratosphere-troposphere exchange mechanism, which will be the focus of a subsequent paper.
Assessing the Impact of Observations on the Prediction of Effective Atmospheric Angular Momentum from NAVGEM

NASA Astrophysics Data System (ADS)

Baker, N. L.; Langland, R.

2016-12-01

Variations in Earth rotation are measured by comparing a time based on Earth's variable rotation rate about its axis to a time standard based on an internationally coordinated ensemble of atomic clocks that provide a uniform time scale. The variability of Earth's rotation is partly due to the changes in angular momentum that occur in the atmosphere and ocean as weather patterns and ocean features develop, propagate, and dissipate. The NAVGEM Effective Atmospheric Angular Momentum Functions (EAAMF) and their predictions are computed following Barnes et al. (1983), and provided to the U.S. Naval Observatory daily. These along with similar data from the NOAA GFS model are used to calculate and predict the Earth orientation parameters (Stamatakos et al., 2016). The Navy's high-resolution global weather prediction system consists of the Navy Global Environmental Model (NAVGEM; Hogan et al., 2014) and a hybrid four-dimensional variational data assimilation system (4DVar) (Kuhl et al., 2013). An important component of NAVGEM is the Forecast Sensitivity Observation Impact (FSOI). FSOI is a mathematical method to quantify the contribution of individual observations or sets of observations to the reduction in the 24-hr forecast error (Langland and Baker, 2004). The FSOI allows for dynamic monitoring of the relative quality and value of the observations assimilated by NAVGEM, and the relative ability of the data assimilation system to effectively use the observation information to generate an improved forecast. For this study, along with the FSOI based on the global moist energy error norm, we computed the FSOI using an error norm based on the Effective Angular Momentum Functions. This modification allowed us to assess which observations were most beneficial in reducing the 24-hr forecast error for the atmospheric angular momentum.
Current Global Absolute Plate Velocities Inferred from the Trends of Hotspot Tracks: Implications for Motion between Groups of Hotspots and Comparison and Combination with Absolute Velocities Inferred from the Orientation of Seismic Anisotropy

NASA Astrophysics Data System (ADS)

Wang, C.; Gordon, R. G.; Zheng, L.

2016-12-01

Hotspot tracks are widely used to estimate the absolute velocities of plates, i.e., relative to the lower mantle. Knowledge of current motion between hotspots is important for both plate kinematics and mantle dynamics and informs the discussion on the origin of the Hawaiian-Emperor Bend. Following Morgan & Morgan (2007), we focus only on the trends of young hotspot tracks and omit volcanic propagation rates. The dispersion of the trends can be partitioned into between-plate and within-plate dispersion. Applying the method of Gripp & Gordon (2002) to the hotspot trend data set of Morgan & Morgan (2007) constrained to the MORVEL relative plate angular velocities (DeMets et al., 2010) results in a standard deviation of the 56 hotspot trends of 22°. The largest angular misfits tend to occur on the slowest moving plates. Alternatively, estimation of best-fitting poles to hotspot tracks on the nine individual plates, results in a standard deviation of trends of only 13°, a statistically significant reduction from the introduction of 15 additional adjustable parameters. If all of the between-plate misfit is due to motion of groups of hotspots (beneath different plates), nominal velocities relative to the mean hotspot reference frame range from 1 to 4 mm/yr with the lower bounds ranging from 1 to 3 mm/yr and the greatest upper bound being 8 mm/yr. These are consistent with bounds on motion between Pacific and Indo-Atlantic hotspots over the past ≈50 Ma, which range from zero (lower bound) to 8 to 13 mm/yr (upper bounds) (Koivisto et al., 2014). We also determine HS4-MORVEL, a new global set of plate angular velocities relative to the hotspots constrained to consistency with the MORVEL relative plate angular velocities, using a two-tier analysis similar to that used by Zheng et al. (2014) to estimate the SKS-MORVEL global set of absolute plate velocities fit to the orientation of seismic anisotropy. We find that the 95% confidence limits of HS4-MORVEL and SKS-MORVEL overlap substantially and that the two sets of angular velocities differ insignificantly. Thus we combine the two sets of angular velocities to estimate ABS-MORVEL, an optimal set of global angular velocities consistent with both hotspot tracks and seismic anisotropy. ABS-MORVEL has more compact confidence limits than either SKS-MORVEL or HS4-MORVEL.
Variations in atmospheric angular momentum

NASA Technical Reports Server (NTRS)

Rosen, R. D.; Salstein, D. A.

1981-01-01

Twice-daily values of the atmosphere's angular momentum about the polar axis during the five years from 1976 through 1980 are presented in graphs and a table. The compilation is based on a global data set, incorporating 90 percent of the mass of the atmosphere. The relationship between changes in the angular momentum of the atmosphere and changes in the length of day is described, as are the main sources of error in the data. The variability in angular momentum is revealed in a preliminary fashion by means of a spectral decomposition. The data presented should stimulate comparisons with other measures of the length of day and so provide a basis for greater understanding of Earth-atmosphere interactions.
Studying AGN Jets At Extreme Angular Resolution

NASA Astrophysics Data System (ADS)

Bruni, Gabriele

2016-10-01

RadioAstron is a 10m antenna orbiting on the Russian Speckt-R spacecraft, launched in 2011. Performing radio interferometry with a global array of ground telescopes, it is providing record angular resolution. The Key Science Project on AGN polarization is exploiting it to study in great detail the configuration of magnetic fields in AGN jets, and understand their formation and collimation. To date, the project has already achieved the highest angular resolution image ever obtained in Astronomy, and detected brightness temperatures exceeding the ones predicted by theory of AGN.

The Mass and Angular Momentum Balance of the Zonally-Averaged Global Circulation.

DTIC Science & Technology

1981-01-01

2 2SFSf F SO~ ABSTRACT (0m-l n oerse~e side Ht moeoeei md fdeutly’ by Week now"*ee Li ATTACHED hO u 47 EDI TIo OP 1 NOV6 Ies OBSOLETE UNCLASS 82 09 28...eddies, and transient circulat.@ns, respec tively. rigeree 12 and 13 displa the vertical sad meridional distribution of relat’.ve angular momentum trass...the transient component is the dominant mode of angular momentum transport in January. It is poleward at virtually all latitudes in each hemisphere
Estimates of success in patients with sciatica due to lumbar disc herniation depend upon outcome measure.

PubMed

Haugen, Anne Julsrud; Grøvle, Lars; Brox, Jens Ivar; Natvig, Bård; Keller, Anne; Soldal, Dag; Grotle, Margreth

2011-10-01

The objectives were to estimate the cut-off points for success on different sciatica outcome measures and to determine the success rate after an episode of sciatica by using these cut-offs. A 12-month multicenter observational study was conducted on 466 patients with sciatica and lumbar disc herniation. The cut-off values were estimated by ROC curve analyses using Completely recovered or Much better on a 7-point global change scale as external criterion for success. The cut-off values (references in brackets) at 12 months were leg pain VAS 17.5 (0-100), back pain VAS 22.5 (0-100), Sciatica Bothersomeness Index 6.5 (0-24), Maine-Seattle Back Questionnaire 4.5 (0-12), and the SF-36 subscales bodily pain 51.5, and physical functioning 81.7 (0-100, higher values indicate better health). In conclusion, the success rates at 12 months varied from 49 to 58% depending on the measure used. The proposed cut-offs may facilitate the comparison of success rates across studies.
Observing Solar Radio Bursts from the Lunar Surface

NASA Technical Reports Server (NTRS)

MacDowall, R. J.; Lazio, T. J.; Bale, S. D.; Burns, J.; Gopalswamy, N.; Jones, D. L.; Kaiser, M. L.; Kasper, J.; Weiler, K. W.

2010-01-01

Locating low frequency radio observatories on the lunar surface has a number of advantages. Here, we describe the Radio Observatory for Lunar Sortie Science (ROLSS), a concept for a low frequency, radio imaging interferometric array designed to study particle acceleration in the corona and inner heliosphere. ROLSS would be deployed during an early lunar sortie or by a robotic rover as part of an unmanned landing. The prime science mission is to image type II and type III solar radio bursts with the aim of determining the sites at and mechanisms by which the radiating particles are accelerated. Secondary science goals include constraining the density of the lunar ionosphere by searching for a low radio frequency cutoff of the solar radio emissions and constraining the low energy electron population in astrophysical sources. Furthermore, ROLSS serves a pathfinder function for larger lunar radio arrays. Key design requirements on ROLES include the operational frequency and angular resolution. The electron densities in the solar corona and inner heliosphere are such that the relevant emission occurs below 10 MHz, essentially unobservable from Earth's surface due to the terrestrial ionospheric cutoff. Resolving the potential sites of particle acceleration requires an instrument with an angular resolution of at least 2 deg, equivalent to a linear array size of approximately 500 meters. Operations would consist of data acquisition during the lunar day, with regular data downlinks. The major components of the ROLSS array are 3 antenna arms arranged in a Y shape, with a central electronics package (CEP). Each antenna arm is a linear strip of polyimide film (e.g., Kapton (TM)) on which 16 single polarization dipole antennas are located by depositing a conductor (e.g., silver). The arms also contain transmission lines for carrying the radio signals from the science antennas to the CEP.
Global and local approaches to population analysis: Bonding patterns in superheavy element compounds

NASA Astrophysics Data System (ADS)

Oleynichenko, Alexander; Zaitsevskii, Andréi; Romanov, Stepan; Skripnikov, Leonid V.; Titov, Anatoly V.

2018-03-01

Relativistic effective atomic configurations of superheavy elements Cn, Nh and Fl and their lighter homologues (Hg, Tl and Pb) in their simple compounds with fluorine and oxygen are determined using the analysis of local properties of molecular Kohn-Sham density matrices in the vicinity of heavy nuclei. The difference in populations of atomic spinors with the same orbital angular momentum and different total angular momenta is demonstrated to be essential for understanding the peculiarities of chemical bonding in superheavy element compounds. The results are fully compatible with those obtained by the relativistic iterative version of conventional projection analysis of global density matrices.
ϕ Meson Spin Alignment and the Azimuthal Angle Dependence of Λ (Λ) Polarization in Au+Au collisions at RHIC

NASA Astrophysics Data System (ADS)

Tu, Biao

2018-02-01

Initial large global angular momentum in non-central relativistic heavy-ion collisions can produce strong vorticity, and through the spin-orbit coupling, causes the spin of particles to align with the system's global angular momentum. We present the azimuthal angle dependent (relative to the reaction plane) polarization for Λ and Λ in mid-central Au+Au collisions at = 200 GeV. We also present the ϕ meson spin alignment parameter, ρ00 in Au+Au collisions at = 19.6, 27, 39, 62.4 and 200 GeV. The implications of the results are discussed.
The vela pulsar: results from the first year of FERMI lat observations

DOE PAGES

Abdo, A. A.; Ackermann, M.; Ajello, M.; ...

2010-03-18

Here, we report on analysis of timing and spectroscopy of the Vela pulsar using 11 months of observations with the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope. The intrinsic brightness of Vela at GeV energies combined with the angular resolution and sensitivity of the LAT allows us to make the most detailed study to date of the energy-dependent light curves and phase-resolved spectra, using a LAT-derived timing model. The light curve consists of two peaks (P1 and P2) connected by bridge emission containing a third peak (P3). We have confirmed the strong decrease of the P1/P2 ratiomore » with increasing energy seen with EGRET and previous Fermi LAT data, and observe that P1 disappears above 20 GeV. The increase with energy of the mean phase of the P3 component can be followed with much greater detail, showing that P3 and P2 are present up to the highest energies of pulsation. We find significant pulsed emission at phases outside the main profile, indicating that magnetospheric emission exists over 80% of the pulsar period. With increased high-energy counts the phase-averaged spectrum is seen to depart from a power law with simple exponential cutoff, and is better fit with a more gradual cutoff. The spectra in fixed-count phase bins are well fit with power laws with exponential cutoffs, revealing a strong and complex phase dependence of the cutoff energy, especially in the peaks. Finally, by combining these results with predictions of the outer magnetosphere models that map emission characteristics to phase, it will be possible to probe the particle acceleration and the structure of the pulsar magnetosphere with unprecedented detail.« less
Neutron-neutron angular correlations in spontaneous fission of 252Cf and 240Pu

NASA Astrophysics Data System (ADS)

Verbeke, J. M.; Nakae, L. F.; Vogt, R.

2018-04-01

Background: Angular anisotropy has been observed between prompt neutrons emitted during the fission process. Such an anisotropy arises because the emitted neutrons are boosted along the direction of the parent fragment. Purpose: To measure the neutron-neutron angular correlations from the spontaneous fission of 252Cf and 240Pu oxide samples using a liquid scintillator array capable of pulse-shape discrimination. To compare these correlations to simulations combining the Monte Carlo radiation transport code MCNPX with the fission event generator FREYA. Method: Two different analysis methods were used to study the neutron-neutron correlations with varying energy thresholds. The first is based on setting a light output threshold while the second imposes a time-of-flight cutoff. The second method has the advantage of being truly detector independent. Results: The neutron-neutron correlation modeled by FREYA depends strongly on the sharing of the excitation energy between the two fragments. The measured asymmetry enabled us to adjust the FREYA parameter x in 240Pu, which controls the energy partition between the fragments and is so far inaccessible in other measurements. The 240Pu data in this analysis was the first available to quantify the energy partition for this isotope. The agreement between data and simulation is overall very good for 252Cf(sf ) and 240Pu(sf ) . Conclusions: The asymmetry in the measured neutron-neutron angular distributions can be predicted by FREYA. The shape of the correlation function depends on how the excitation energy is partitioned between the two fission fragments. Experimental data suggest that the lighter fragment is disproportionately excited.
A goal-based angular adaptivity method for thermal radiation modelling in non grey media

NASA Astrophysics Data System (ADS)

Soucasse, Laurent; Dargaville, Steven; Buchan, Andrew G.; Pain, Christopher C.

2017-10-01

This paper investigates for the first time a goal-based angular adaptivity method for thermal radiation transport, suitable for non grey media when the radiation field is coupled with an unsteady flow field through an energy balance. Anisotropic angular adaptivity is achieved by using a Haar wavelet finite element expansion that forms a hierarchical angular basis with compact support and does not require any angular interpolation in space. The novelty of this work lies in (1) the definition of a target functional to compute the goal-based error measure equal to the radiative source term of the energy balance, which is the quantity of interest in the context of coupled flow-radiation calculations; (2) the use of different optimal angular resolutions for each absorption coefficient class, built from a global model of the radiative properties of the medium. The accuracy and efficiency of the goal-based angular adaptivity method is assessed in a coupled flow-radiation problem relevant for air pollution modelling in street canyons. Compared to a uniform Haar wavelet expansion, the adapted resolution uses 5 times fewer angular basis functions and is 6.5 times quicker, given the same accuracy in the radiative source term.
Global finite-time attitude stabilization for rigid spacecraft in the exponential coordinates

NASA Astrophysics Data System (ADS)

Shi, Xiao-Ning; Zhou, Zhi-Gang; Zhou, Di

2018-06-01

This paper addresses the global finite-time attitude stabilisation problem on the special orthogonal group (SO(3)) for a rigid spacecraft via homogeneous feedback approach. Considering the topological and geometric properties of SO(3), the logarithm map is utilised to transform the stabilisation problem on SO(3) into the one on its associated Lie algebra (?). A model-independent discontinuous state feedback plus dynamics compensation scheme is constructed to achieve the global finite-time attitude stabilisation in a coordinate-invariant way. In addition, to address the absence of angular velocity measurements, a sliding mode observer is proposed to reconstruct the unknown angular velocity information within finite time. Then, an observer-based finite-time output feedback control strategy is obtained. Numerical simulations are finally performed to demonstrate the effectiveness of the proposed finite-time controllers.
Reduced modeling of the magnetorotational instability

NASA Astrophysics Data System (ADS)

Jamroz, Ben F.

2009-06-01

Accretion describes the process by which matter in an astrophysical disk falls onto a central massive object. Accretion disks are present in many astrophysical situations including binary star systems, young stellar objects, and near black holes at the center of galaxies. Measurements from observations of these disks have shown that viscous processes are unable to transport the necessary levels of angular momentum needed for accretion. Therefore, accretion requires an efficient mechanism of angular momentum transport. Mixing by turbulent processes greatly enhances the level of angular momentum transport in a turbulent fluid. Thus, the generation of turbulence in these disks may provide the mechanism needed for accretion. A classical result of hydrodynamic theory is that typical accretion disks are hydrodynamically stable to shear instabilities, since the specific angular momentum increases outwards. Other processes of generating hydrodynamic turbulence (barotropic instability, baroclinic instability, sound wave, shock waves, finite amplitude instabilities) may be present in these disks, however, none of these mechanisms has been shown to produce the level of angular momentum transport needed for accretion. Hydrodynamical turbulence does not produce enough angular momentum transport to produce the level of accretion observed in astrophysical accretion disks. The leading candidate for the source of turbulence leading to the transport of angular momentum is the magnetorotational instability, a linear axisymmetric instability of electrically conducting fluid in the presence of an imposed magnetic field and shear (or differential rotation). This instability is an efficient mechanism of angular momentum transport generating the level of transport needed for accretion. The level of effective angular momentum transport is determined by the saturated state of sustained turbulence generated by the instability. The mechanism of nonlinear saturation of this instability is not well understood. Many recent numerical investigations of this problem are performed in a local domain, where the global cylindrical background state is projected onto a local Cartesian domain. The resulting system is then numerically modeled within a "shearing box" framework to obtain estimates of angular momentum transport and therefore accretion. However, the simplified geometry of the local domain, and the projection of global quantities leads to a model where the instability is able to grow unboundedly. Utilizing disparate characteristic scales, this thesis presents a reduced asymptotic model for the magnetorotational instability that allows a large scale feedback of local stresses (Reynolds, Maxwell and mixed) onto the projected background state. This system is investigated numerically to determine the impact of allowing this feedback on the saturated level of angular momentum transport.
Space Particle Hazard Specification, Forecasting, and Mitigation

DTIC Science & Technology

2007-11-30

Automated FTP scripts permitted users to automatically update their global input parameter data set directly from the National Oceanic and...of CEASE capabilities. The angular field-of-view for CEASE is relatively large and will not allow for pitch angle resolved measurements. However... angular zones spanning 120° in the plane containing the magnetic field with an approximate 4° width in the direction perpendicular to the look-plane
Consistent searches for SMEFT effects in non-resonant dijet events

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

Alte, Stefan; Konig, Matthias; Shepherd, William

Here, we investigate the bounds which can be placed on generic new-physics contributions to dijet production at the LHC using the framework of the Standard Model Effective Field Theory, deriving the first consistently-treated EFT bounds from non-resonant high-energy data. We recast an analysis searching for quark compositeness, equivalent to treating the SM with one higher-dimensional operator as a complete UV model. In order to reach consistent, model-independent EFT conclusions, it is necessary to truncate the EFT effects consistently at ordermore » $$1/\\Lambda^2$$ and to include the possibility of multiple operators simultaneously contributing to the observables, neither of which has been done in previous searches of this nature. Furthermore, it is important to give consistent error estimates for the theoretical predictions of the signal model, particularly in the region of phase space where the probed energy is approaching the cutoff scale of the EFT. There are two linear combinations of operators which contribute to dijet production in the SMEFT with distinct angular behavior; we identify those linear combinations and determine the ability of LHC searches to constrain them simultaneously. Consistently treating the EFT generically leads to weakened bounds on new-physics parameters. These constraints will be a useful input to future global analyses in the SMEFT framework, and the techniques used here to consistently search for EFT effects are directly applicable to other off-resonance signals.« less
Consistent searches for SMEFT effects in non-resonant dijet events

DOE PAGES

Alte, Stefan; Konig, Matthias; Shepherd, William

2018-01-19

Here, we investigate the bounds which can be placed on generic new-physics contributions to dijet production at the LHC using the framework of the Standard Model Effective Field Theory, deriving the first consistently-treated EFT bounds from non-resonant high-energy data. We recast an analysis searching for quark compositeness, equivalent to treating the SM with one higher-dimensional operator as a complete UV model. In order to reach consistent, model-independent EFT conclusions, it is necessary to truncate the EFT effects consistently at ordermore » $$1/\\Lambda^2$$ and to include the possibility of multiple operators simultaneously contributing to the observables, neither of which has been done in previous searches of this nature. Furthermore, it is important to give consistent error estimates for the theoretical predictions of the signal model, particularly in the region of phase space where the probed energy is approaching the cutoff scale of the EFT. There are two linear combinations of operators which contribute to dijet production in the SMEFT with distinct angular behavior; we identify those linear combinations and determine the ability of LHC searches to constrain them simultaneously. Consistently treating the EFT generically leads to weakened bounds on new-physics parameters. These constraints will be a useful input to future global analyses in the SMEFT framework, and the techniques used here to consistently search for EFT effects are directly applicable to other off-resonance signals.« less
Constraints on the Energy Content of the Universe from a Combination of Galaxy Cluster Observables

NASA Technical Reports Server (NTRS)

Molnar, Sandor M.; Haiman, Zoltan; Birkinshaw, Mark; Mushotzky, Richard F.

2003-01-01

We demonstrate that constraints on cosmological parameters from the distribution of clusters as a function of redshift (dN/dz) are complementary to accurate angular diameter distance (D(sub A)) measurements to clusters, and their combination significantly tightens constraints on the energy density content of the Universe. The number counts can be obtained from X-ray and/or SZ (Sunyaev-Ze'dovich effect) surveys, and the angular diameter distances can be determined from deep observations of the intra-cluster gas using their thermal bremsstrahlung X-ray emission and the SZ effect. We combine constraints from simulated cluster number counts expected from a 12 deg(sup 2) SZ cluster survey and constraints from simulated angular diameter distance measurements based on the X-ray/SZ method assuming a statistical accuracy of 10% in the angular diameter distance determination of 100 clusters with redshifts less than 1.5. We find that Omega(sub m), can be determined within about 25%, Omega(sub lambda) within 20% and w within 16%. We show that combined dN/dz+(sub lambda) constraints can be used to constrain the different energy densities in the Universe even in the presence of a few percent redshift dependent systematic error in D(sub lambda). We also address the question of how best to select clusters of galaxies for accurate diameter distance determinations. We show that the joint dN/dz+ D(lambda) constraints on cosmological parameters for a fixed target accuracy in the energy density parameters are optimized by selecting clusters with redshift upper cut-offs in the range 0.55 approx. less than 1. Subject headings: cosmological parameters - cosmology: theory - galaxies:clusters: general
CUTOFF POINT OF THE PHASE ANGLE IN PRE-RADIOTHERAPY CANCER PATIENTS.

PubMed

Souza Thompson Motta, Rachel; Alves Castanho, Ivany; Guillermo Coca Velarde, Luis

2015-11-01

malnutrition is a common complication for cancer patients. The phase angle (PA), direct measurement of bioelectrical impedance analysis (BIA), has been considered a predictor of body cell mass and prognostic indicator. Cutoff points for phase angle (PA) associated with nutritional risk in cancer patients have not been determined yet. assess the possibility of determining the cutoff point for PA to identify nutritional risk in pre-radiotherapy cancer patients. sample group: Patients from both genders diagnosed with cancer and sent for ambulatory radiotherapy. body mass index (BMI), percentage of weight loss (% WL), mid-arm circumference (MAC), triceps skinfold thickness (TST), mid-arm muscle circumference (MAMC), mid-arm muscle area (MAMA), score and categorical assessment obtained using the Patient-Generated Subjective Global Assessment (PG-SGA) form, PA and standardized phase angle (SPA). Kappa coefficient was used to test the degree of agreement between the diagnoses of nutritional risk obtained from several different methods of nutritional assessment. Cutoff points for the PA through anthropometric indicators and PG-SGA were determined by using Receiver Operating Characteristic (ROC) curves, and patient survival was analyzed with the Cox regression method. the cutoff points with the greatest discriminatory power were those obtained from BMI (5.2) and the categorical assessment of PG-SGA (5.4). The diagnosis obtained using these cutoff points showed a significant association with risk of death for the patients in the sample group. we recommend using the cutoff point 5.2 for the PA as a criterion for identifying nutritional risk in pre-radiotherapy cancer patients. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.
Complex wave fields in the interacting one-dimensional Bose gas

NASA Astrophysics Data System (ADS)

Pietraszewicz, J.; Deuar, P.

2018-05-01

We study the temperature regimes of the one-dimensional interacting gas to determine when the matter wave (c-field) theory is, in fact, correct and usable. The judgment is made by investigating the level of discrepancy in many observables at once in comparison to the exact Yang-Yang theory. We also determine what cutoff maximizes the accuracy of such an approach. Results are given in terms of a bound on accuracy, as well as an optimal cutoff prescription. For a wide range of temperatures the optimal cutoff is independent of density or interaction strength and so its temperature-dependent form is suitable for many cloud shapes and, possibly, basis choices. However, this best global choice is higher in energy than most prior determinations. The high value is needed to obtain the correct kinetic energy, but does not detrimentally affect other observables.
Major depressive disorder with psychotic features may lead to misdiagnosis of dementia: a case report and review of the literature.

PubMed

Wagner, Gerhardt S; McClintock, Shawn M; Rosenquist, Peter B; McCall, W Vaughn; Kahn, David A

2011-11-01

Major depressive disorder (MDD) with psychotic features is relatively frequent in patients with greater depressive symptom severity and is associated with a poorer course of illness and greater functional impairment than MDD without psychotic features. Multiple studies have found that patients with psychotic mood disorders demonstrate significantly poorer cognitive performance in a variety of areas than those with nonpsychotic mood disorders. The Mini Mental State Examination (MMSE) and the Dementia Rating Scale, Second Edition (DRS-2) are widely used to measure cognitive functions in research on MDD with psychotic features. Established total raw score cut-offs of 24 on the MMSE and 137 on the DRS-2 in published manuals suggest possible global cognitive impairment and dementia, respectively. Limited research is available on these suggested cut-offs for patients with MDD with psychotic features. We document the therapeutic benefit of electroconvulsive therapy (ECT), which is usually associated with short-term cognitive impairment, in a 68-year-old woman with psychotic depression whose MMSE and DRS-2 scores initially suggested possible global cognitive impairment and dementia. Over the course of four ECT treatments, the patient's MMSE scores progressively increased. After the second ECT treatment, the patient no longer met criteria for global cognitive impairment. With each treatment, depression severity, measured by the 24-item Hamilton Rating Scale for Depression, improved sequentially. Thus, the suggested cut-off scores for the MMSE and the DRS-2 in patients with MDD with psychotic features may in some cases produce false-positive indications of dementia.
Prospective Study of Optimal Obesity Index Cut-Off Values for Predicting Incidence of Hypertension in 18–65-Year-Old Chinese Adults

PubMed Central

Ren, Qian; Su, Chang; Wang, Huijun; Wang, Zhihong; Du, Wenwen; Zhang, Bing

2016-01-01

Background Overweight and obesity increase the risk of elevated blood pressure; most of the studies that serve as a background for the debates on the optimal obesity index cut-off values used cross-sectional samples. The aim of this study was to determine the cut-off values of anthropometric markers for detecting hypertension in Chinese adults with data from prospective cohort. Methods This study determines the best cut-off values for the obesity indices that represent elevated incidence of hypertension in 18–65-year-old Chinese adults using data from the China Health and Nutrition Survey (CHNS) 2006–2011 prospective cohort. Individual body mass index (BMI), waist circumference (WC), waist:hip ratio (WHR) and waist:stature ratio (WSR) were assessed. ROC curves for these obesity indices were plotted to estimate and compare the usefulness of these obesity indices and the corresponding values for the maximum of the Youden indices were considered the optimal cut-off values. Results Five-year cumulative incidences of hypertension were 21.5% (95% CI: 19.4–23.6) in men and 16.5% (95% CI: 14.7–18.2) in women, and there was a significant trend of increased incidence of hypertension with an increase in BMI, WC, WHR or WSR (P for trend < 0.001) in both men and women. The Youden index indicated that the optimal BMI, WC, WHR, WSR cut-off values were 23.53 kg/m2, 83.7 cm, 0.90, and 0.51 among men. The optimal BMI, WC, WHR, WSR cut-off values were 24.25 kg/m2, 79.9 cm, 0.85 and 0.52 among women. Conclusions Our study supported the hypothesis that the cut-off values for BMI and WC that were recently developed by the Working Group on Obesity in China (WGOC), the cut-off values for WHR that were developed by the World Health Organization (WHO), and a global WSR cut-off value of 0.50 may be the appropriate upper limits for Chinese adults. PMID:26934390
An Angular Method with Position Control for Block Mesh Squareness Improvement

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

Yao, J.; Stillman, D.

We optimize a target function de ned by angular properties with a position control term for a basic stencil with a block-structured mesh, to improve element squareness in 2D and 3D. Comparison with the condition number method shows that besides a similar mesh quality regarding orthogonality can be achieved as the former does, the new method converges faster and provides a more uniform global mesh spacing in our numerical tests.
Protoplanetary Disks as (Possibly) Viscous Disks

NASA Astrophysics Data System (ADS)

Rafikov, Roman R.

2017-03-01

Protoplanetary disks are believed to evolve on megayear timescales in a diffusive (viscous) manner as a result of angular momentum transport driven by internal stresses. Here we use a sample of 26 protoplanetary disks resolved by ALMA with measured (dust-based) masses and stellar accretion rates to derive the dimensionless α-viscosity values for individual objects, with the goal of constraining the angular momentum transport mechanism. We find that the inferred values of α do not cluster around a single value, but instead have a broad distribution extending from 10-4 to 0.04. Moreover, they correlate with neither the global disk parameters (mass, size, surface density) nor the stellar characteristics (mass, luminosity, radius). However, we do find a strong linear correlation between α and the central mass accretion rate \\dot{M}. This correlation is unlikely to result from the direct physical effect of \\dot{M} on internal stress on global scales. Instead, we suggest that it is caused by the decoupling of stellar \\dot{M} from the global disk characteristics in one of the following ways: (1) The behavior (and range) of α is controlled by a yet-unidentified parameter (e.g., ionization fraction, magnetic field strength, or geometry), ultimately driving the variation of \\dot{M}. (2) The central \\dot{M} is decoupled from the global accretion rate as a result of an instability, or mass accumulation (or loss in a wind or planetary accretion) in the inner disk. (3) Perhaps the most intriguing possibility is that angular momentum in protoplanetary disks is transported nonviscously, e.g., via magnetohydrodynamic winds or spiral density waves.

Systems and Methods for Determining Inertial Navigation System Faults

NASA Technical Reports Server (NTRS)

Bharadwaj, Raj Mohan (Inventor); Bageshwar, Vibhor L. (Inventor); Kim, Kyusung (Inventor)

2017-01-01

An inertial navigation system (INS) includes a primary inertial navigation system (INS) unit configured to receive accelerometer measurements from an accelerometer and angular velocity measurements from a gyroscope. The primary INS unit is further configured to receive global navigation satellite system (GNSS) signals from a GNSS sensor and to determine a first set of kinematic state vectors based on the accelerometer measurements, the angular velocity measurements, and the GNSS signals. The INS further includes a secondary INS unit configured to receive the accelerometer measurements and the angular velocity measurements and to determine a second set of kinematic state vectors of the vehicle based on the accelerometer measurements and the angular velocity measurements. A health management system is configured to compare the first set of kinematic state vectors and the second set of kinematic state vectors to determine faults associated with the accelerometer or the gyroscope based on the comparison.
Effects of finite coverage on global polarization observables in heavy ion collisions

NASA Astrophysics Data System (ADS)

Lan, Shaowei; Lin, Zi-Wei; Shi, Shusu; Sun, Xu

2018-05-01

In non-central relativistic heavy ion collisions, the created matter possesses a large initial orbital angular momentum. Particles produced in the collisions could be polarized globally in the direction of the orbital angular momentum due to spin-orbit coupling. Recently, the STAR experiment has presented polarization signals for Λ hyperons and possible spin alignment signals for ϕ mesons. Here we discuss the effects of finite coverage on these observables. The results from a multi-phase transport and a toy model both indicate that a pseudorapidity coverage narrower than | η | < ∼ 1 will generate a larger value for the extracted ϕ-meson ρ00 parameter; thus a finite coverage can lead to an artificial deviation of ρ00 from 1/3. We also show that a finite η and pT coverage affect the extracted pH parameter for Λ hyperons when the real pH value is non-zero. Therefore proper corrections are necessary to reliably quantify the global polarization with experimental observables.
Shifts in Summertime Precipitation Accumulation Distributions over the US

NASA Astrophysics Data System (ADS)

Martinez-Villalobos, C.; Neelin, J. D.

2016-12-01

Precipitation accumulations, i.e., the amount of precipitation integrated over the course of an event, is a variable with both important physical and societal implications. Previous observational studies show that accumulation distributions have a characteristic shape, with an approximately power law decrease at first, followed by a sharp decrease at a characteristic large event cutoff scale. This cutoff scale is important as it limits the biggest accumulation events. Stochastic prototypes show that the resulting distributions, and importantly the large event cutoff scale, can be understood as a result of the interplay between moisture loss by precipitation and changes in moisture sinks/sources due to fluctuations in moisture divergence over the course of a precipitation event. The strength of this fluctuating moisture sink/source term is expected to increase under global warming, with both theory and climate model simulations predicting a concomitant increase in the large event cutoff scale. This cutoff scale increase has important consequences as it implies an approximately exponential increase for the largest accumulation events. Given its importance, in this study we characterize and track changes in the distribution of precipitation events accumulations over the contiguous US. Accumulation distributions are calculated using hourly precipitation data from 1700 stations, covering the 1974-2013 period over May-October. The resulting distributions largely follow the aforementioned shape, with individual cutoff scales depending on the local climate. An increase in the large event cutoff scale over this period is observed over several regions over the US, most notably over the eastern third of the US. In agreement with the increase in the cutoff, almost exponential increases in the highest accumulation percentiles occur over these regions, with increases in the 99.9 percentile in the Northeast of 70% for example. The relationship to changes in daily precipitation that have previously been noted and to changes in the moisture budget over this period are examined.
Shifts in Summertime Precipitation Accumulation Distributions over the US

NASA Astrophysics Data System (ADS)

Martinez-Villalobos, C.; Neelin, J. D.

2017-12-01

Precipitation accumulations, i.e., the amount of precipitation integrated over the course of an event, is a variable with both important physical and societal implications. Previous observational studies show that accumulation distributions have a characteristic shape, with an approximately power law decrease at first, followed by a sharp decrease at a characteristic large event cutoff scale. This cutoff scale is important as it limits the biggest accumulation events. Stochastic prototypes show that the resulting distributions, and importantly the large event cutoff scale, can be understood as a result of the interplay between moisture loss by precipitation and changes in moisture sinks/sources due to fluctuations in moisture divergence over the course of a precipitation event. The strength of this fluctuating moisture sink/source term is expected to increase under global warming, with both theory and climate model simulations predicting a concomitant increase in the large event cutoff scale. This cutoff scale increase has important consequences as it implies an approximately exponential increase for the largest accumulation events. Given its importance, in this study we characterize and track changes in the distribution of precipitation events accumulations over the contiguous US. Accumulation distributions are calculated using hourly precipitation data from 1700 stations, covering the 1974-2013 period over May-October. The resulting distributions largely follow the aforementioned shape, with individual cutoff scales depending on the local climate. An increase in the large event cutoff scale over this period is observed over several regions over the US, most notably over the eastern third of the US. In agreement with the increase in the cutoff, almost exponential increases in the highest accumulation percentiles occur over these regions, with increases in the 99.9 percentile in the Northeast of 70% for example. The relationship to changes in daily precipitation that have previously been noted and to changes in the moisture budget over this period are examined.
Smoothed dissipative particle dynamics with angular momentum conservation

NASA Astrophysics Data System (ADS)

Müller, Kathrin; Fedosov, Dmitry A.; Gompper, Gerhard

2015-01-01

Smoothed dissipative particle dynamics (SDPD) combines two popular mesoscopic techniques, the smoothed particle hydrodynamics and dissipative particle dynamics (DPD) methods, and can be considered as an improved dissipative particle dynamics approach. Despite several advantages of the SDPD method over the conventional DPD model, the original formulation of SDPD by Español and Revenga (2003) [9], lacks angular momentum conservation, leading to unphysical results for problems where the conservation of angular momentum is essential. To overcome this limitation, we extend the SDPD method by introducing a particle spin variable such that local and global angular momentum conservation is restored. The new SDPD formulation (SDPD+a) is directly derived from the Navier-Stokes equation for fluids with spin, while thermal fluctuations are incorporated similarly to the DPD method. We test the new SDPD method and demonstrate that it properly reproduces fluid transport coefficients. Also, SDPD with angular momentum conservation is validated using two problems: (i) the Taylor-Couette flow with two immiscible fluids and (ii) a tank-treading vesicle in shear flow with a viscosity contrast between inner and outer fluids. For both problems, the new SDPD method leads to simulation predictions in agreement with the corresponding analytical theories, while the original SDPD method fails to capture properly physical characteristics of the systems due to violation of angular momentum conservation. In conclusion, the extended SDPD method with angular momentum conservation provides a new approach to tackle fluid problems such as multiphase flows and vesicle/cell suspensions, where the conservation of angular momentum is essential.
Detection of depression in acute schizophrenia: sensitivity and specificity of 2 standard observer rating scales.

PubMed

Müller, Matthias J; Müller, Kay-Maria; Fellgiebel, Andreas

2006-05-01

To compare the psychometric properties of the Calgary Depression Rating Scale (CDRS) and the Hamilton Depression Rating Scale (HDRS) for severity assessment of depression in acute schizophrenia. During clinical routine treatment, we investigated 119 inpatients with acute schizophrenia, using the CDRS, the HDRS, and a global 4-point Depression Severity Scale (DEP-SEV). We compared CDRS and HDRS sum scores regarding their diagnostic accuracy, with global severity of depression as the criterion. We estimated sensitivity and specificity on the basis of receiver operating characteristic curves. According to global clinical ratings (DEP-SEV), 31% of patients had no depression, 19% had mild, 31% had moderate, and 19% had severe depression. Sensitivity was significantly higher (P < 0.05) for the CDRS than for the HDRS to assess mild (0.94 vs 0.76, cut-off 3 vs 10 points) or severe depression (1.00 vs 0.78, cut-off 11 vs 22 points); specificity was comparably high (> or = 0.88) for both scales. Despite the fact that both scales were effective in separating mild, moderate, and severe depression, significant advantages emerged for the CDRS to detect mild or severe depression in schizophrenia.
ANGULAR MOMENTUM TRANSPORT BY ACOUSTIC MODES GENERATED IN THE BOUNDARY LAYER. I. HYDRODYNAMICAL THEORY AND SIMULATIONS

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

Belyaev, Mikhail A.; Rafikov, Roman R.; Stone, James M., E-mail: rrr@astro.princeton.edu

The nature of angular momentum transport in the boundary layers of accretion disks has been one of the central and long-standing issues of accretion disk theory. In this work we demonstrate that acoustic waves excited by supersonic shear in the boundary layer serve as an efficient mechanism of mass, momentum, and energy transport at the interface between the disk and the accreting object. We develop the theory of angular momentum transport by acoustic modes in the boundary layer, and support our findings with three-dimensional hydrodynamical simulations, using an isothermal equation of state. Our first major result is the identification ofmore » three types of global modes in the boundary layer. We derive dispersion relations for each of these modes that accurately capture the pattern speeds observed in simulations to within a few percent. Second, we show that angular momentum transport in the boundary layer is intrinsically nonlocal, and is driven by radiation of angular momentum away from the boundary layer into both the star and the disk. The picture of angular momentum transport in the boundary layer by waves that can travel large distances before dissipating and redistributing angular momentum and energy to the disk and star is incompatible with the conventional notion of local transport by turbulent stresses. Our results have important implications for semianalytical models that describe the spectral emission from boundary layers.« less
Induced Ellipticity for Inspiraling Binary Systems

NASA Astrophysics Data System (ADS)

Randall, Lisa; Xianyu, Zhong-Zhi

2018-01-01

Although gravitational waves tend to erase eccentricity of an inspiraling binary system, ellipticity can be generated in the presence of surrounding matter. We present a semianalytical method for understanding the eccentricity distribution of binary black holes (BHs) in the presence of a supermassive BH in a galactic center. Given a matter distribution, we show how to determine the resultant eccentricity analytically in the presence of both tidal forces and evaporation up to one cutoff and one matter-distribution-independent function, paving the way for understanding the environment of detected inspiraling BHs. We furthermore generalize Kozai–Lidov dynamics to situations where perturbation theory breaks down for short time intervals, allowing more general angular momentum exchange, such that eccentricity is generated even when all bodies orbit in the same plane.
Stringent limits on the amplitude of Alfvénic perturbations at high-beta

NASA Astrophysics Data System (ADS)

Squire, J.; Quataert, E.; Schekochihin, A. A.; Bale, S. D.; Chen, C. H. K.; Strumik, M.

2016-12-01

It is shown that low-collisionality plasmas cannot support linearly polarized shear-Alfvén fluctuations above a critical amplitude δB⊥/B0 ˜ β-1/2, where β is the ratio of thermal to magnetic pressure. Above this cutoff, a developing fluctuation will generate a pressure anisotropy that is sufficient to destabilize itself through the parallel firehose instability. This causes the wave frequency to approach zero, interrupting the fluctuation before any oscillation. The magnetic field lines rapidly relax into a sequence of angular zig-zag structures. Such a restrictive bound on shear-Alfvén-wave amplitudes has interesting implications for magnetized turbulence in weakly collisional plasmas, in particular for the solar wind at 1AU where β 1.
Resolving Tropical Cyclone Intensity in Models

NASA Astrophysics Data System (ADS)

Davis, C. A.

2018-02-01

In recent years, global weather forecast models and global climate models have begun to depict intense tropical cyclones, even up to category 5 on the Saffir-Simpson scale. In light of the limitation of horizontal resolution in such models, the author performs calculations, using the extended Best Track data for Atlantic tropical cyclones, to estimate the ability of models with differing grid spacing to represent Atlantic tropical cyclone intensity statistically. Results indicate that, under optimistic assumptions, models with horizontal grid spacing of one fourth degree or coarser should not produce a realistic number of category 4 and 5 storms unless there are errors in spatial attributes of the wind field. Furthermore, the case of Irma (2017) is used to demonstrate the importance of a realistic depiction of angular momentum and to motivate the use of angular momentum in model evaluation.
A comparative study of methods for describing non-adiabatic coupling: diabatic representation of the 1Sigma +/1Pi HOH and HHO conical intersections

NASA Astrophysics Data System (ADS)

Dobbyn, Abigail J.; Knowles, Peter J.

A number of established techniques for obtaining diabatic electronic states in small molecules are critically compared for the example of the X and B states in the water molecule, which contribute to the two lowest-energy conical intersections. Integration of the coupling matrix elements and analysis of configuration mixing coefficients both produce reliable diabatic states globally. Methods relying on diagonalization of dipole moment and angular momentum operators are shown to fail in large regions of coordinate space. However, the use of transition angular momentum matrix elements involving the A state, which is degenerate with B at the conical intersections, is successful globally, provided that an appropriate choice of coordinates is made. Long range damping of non-adiabatic coupling to give correct asymptotic mixing angles also is investigated.
Hydrological signal in polar motion excitation from a combination of geophysical and gravimetric series

NASA Astrophysics Data System (ADS)

Nastula, Jolanta; Winska, Malgorzata; Salstein, David A.

2015-08-01

One can estimate the hydrological signal in polar motion excitation as a residual, namely the difference between observed geodetic excitation functions (Geodetic Angular Momentum, GAM) and the sum of Atmospheric Angular Momentum (AAM) and Oceanic Angular Momentum (OAM).The aim of this study is to find the optimal model and results for hydrological excitation functions in terms of their agreement with the computed difference between GAM and atmospheric and oceanic signals.The atmospheric and oceanic model-based data that we use in this study are the geophysical excitation functions of AAM, OAM available from the Special Bureaus for the Atmosphere and Oceans of the Geophysical Global Fluids Center (GGFC) of the International Earth Rotation and Reference Systems Service (IERS). For the atmosphere and ocean, these functions are based on the mass and motion fields of the fluids.Global models of land hydrology are used to estimate hydrological excitation functions of polar motion (Hydrological Angular Momentum - HAM). These HAM series are the mass of water substance determined from the various types of land-based hydrological reservoirs. In addition the HAM are estimated from spherical harmonic coefficients of the Earth’s gravity field. We use several sets of degree-2, order-1 harmonics of the Earth’s gravity field, derived from the Gravity Recovery and Climate Experiment (GRACE), Satellite Laser Ranging (SLR), and Global Navigation Satellite Systems (GNSS) data.Finally, these several different HAM series are used to determine the best model of hydrological excitation of polar motion. The model is found by looking for the combination of these series that fits the geodetic residuals using the least-square method.In addition, we will access model results from the Coupled Model Intercomparison Project, fifth experiment (CMIP-5) to examine atmospheric excitations from the twentieth century and estimates for the twenty-first century to see the possible signals and trends of these excitation series to help understand the potential range in the derived of hydrological excitation results.
Contributions of high-altitude winds and atmospheric moment of inertia to the atmospheric angular momentum-earth rotation relationship

NASA Technical Reports Server (NTRS)

Taylor, H. A., Jr.; Mayr, H. G.; Kramer, L.

1985-01-01

For many years it has been recognized that recurrent modulations occur in the time series of the earth's rotation rate or, alternatively, the change in the length of the day (Delta-LOD). Studies relating Delta-LOD to global patterns of zonal winds have confirmed that the variability of atmospheric angular momentum (M) is of sufficient magnitude to account for a large portion of the gross periodicities observed in the earth rotation. The present investigation is concerned with the importance of the contributions of the moment of inertia and high-altitude winds to the angular momentum budget. On the basis of an analysis of the various factors, it is found that within the available data, contributions of high-altitude winds and atmospheric moment of inertia reach levels detectable in the atmospheric angular momentum budget. Nevertheless, for the period December 1978 to December 1979 these contributions are not sufficient to resolve the apparent short-term discrepancies which are evident between Delta-LOD and M.
DOE Office of Scientific and Technical Information (OSTI.GOV)

Müller, Kathrin, E-mail: k.mueller@fz-juelich.de; Fedosov, Dmitry A., E-mail: d.fedosov@fz-juelich.de; Gompper, Gerhard, E-mail: g.gompper@fz-juelich.de

Smoothed dissipative particle dynamics (SDPD) combines two popular mesoscopic techniques, the smoothed particle hydrodynamics and dissipative particle dynamics (DPD) methods, and can be considered as an improved dissipative particle dynamics approach. Despite several advantages of the SDPD method over the conventional DPD model, the original formulation of SDPD by Español and Revenga (2003) [9], lacks angular momentum conservation, leading to unphysical results for problems where the conservation of angular momentum is essential. To overcome this limitation, we extend the SDPD method by introducing a particle spin variable such that local and global angular momentum conservation is restored. The new SDPDmore » formulation (SDPD+a) is directly derived from the Navier–Stokes equation for fluids with spin, while thermal fluctuations are incorporated similarly to the DPD method. We test the new SDPD method and demonstrate that it properly reproduces fluid transport coefficients. Also, SDPD with angular momentum conservation is validated using two problems: (i) the Taylor–Couette flow with two immiscible fluids and (ii) a tank-treading vesicle in shear flow with a viscosity contrast between inner and outer fluids. For both problems, the new SDPD method leads to simulation predictions in agreement with the corresponding analytical theories, while the original SDPD method fails to capture properly physical characteristics of the systems due to violation of angular momentum conservation. In conclusion, the extended SDPD method with angular momentum conservation provides a new approach to tackle fluid problems such as multiphase flows and vesicle/cell suspensions, where the conservation of angular momentum is essential.« less
Aerodynamic coefficient identification package dynamic data accuracy determinations: Lessons learned

NASA Technical Reports Server (NTRS)

Heck, M. L.; Findlay, J. T.; Compton, H. R.

1983-01-01

The errors in the dynamic data output from the Aerodynamic Coefficient Identification Packages (ACIP) flown on Shuttle flights 1, 3, 4, and 5 were determined using the output from the Inertial Measurement Units (IMU). A weighted least-squares batch algorithm was empolyed. Using an averaging technique, signal detection was enhanced; this allowed improved calibration solutions. Global errors as large as 0.04 deg/sec for the ACIP gyros, 30 mg for linear accelerometers, and 0.5 deg/sec squared in the angular accelerometer channels were detected and removed with a combination is bias, scale factor, misalignment, and g-sensitive calibration constants. No attempt was made to minimize local ACIP dynamic data deviations representing sensed high-frequency vibration or instrument noise. Resulting 1sigma calibrated ACIP global accuracies were within 0.003 eg/sec, 1.0 mg, and 0.05 deg/sec squared for the gyros, linear accelerometers, and angular accelerometers, respectively.
Proposed Diagnostic Criteria for Smartphone Addiction

PubMed Central

Lin, Yu-Hsuan; Chiang, Chih-Lin; Lin, Po-Hsien; Chang, Li-Ren; Ko, Chih-Hung; Lee, Yang-Han

2016-01-01

Background Global smartphone penetration has led to unprecedented addictive behaviors. The aims of this study are to develop diagnostic criteria of smartphone addiction and to examine the discriminative ability and the validity of the diagnostic criteria. Methods We developed twelve candidate criteria for characteristic symptoms of smartphone addiction and four criteria for functional impairment caused by excessive smartphone use. The participants consisted of 281 college students. Each participant was systematically assessed for smartphone-using behaviors by psychiatrist’s structured diagnostic interview. The sensitivity, specificity, and diagnostic accuracy of the candidate symptom criteria were analyzed with reference to the psychiatrists’ clinical global impression. The optimal model selection with its cutoff point of the diagnostic criteria differentiating the smartphone addicted subjects from non-addicted subjects was then determined by the best diagnostic accuracy. Results Six symptom criteria model with optimal cutoff point were determined based on the maximal diagnostic accuracy. The proposed smartphone addiction diagnostic criteria consisted of (1) six symptom criteria, (2) four functional impairment criteria and (3) exclusion criteria. Setting three symptom criteria as the cutoff point resulted in the highest diagnostic accuracy (84.3%), while the sensitivity and specificity were 79.4% and 87.5%, respectively. We suggested determining the functional impairment by two or more of the four domains considering the high accessibility and penetration of smartphone use. Conclusion The diagnostic criteria of smartphone addiction demonstrated the core symptoms “impaired control” paralleled with substance related and addictive disorders. The functional impairment involved multiple domains provide a strict standard for clinical assessment. PMID:27846211
Proposed Diagnostic Criteria for Smartphone Addiction.

PubMed

Lin, Yu-Hsuan; Chiang, Chih-Lin; Lin, Po-Hsien; Chang, Li-Ren; Ko, Chih-Hung; Lee, Yang-Han; Lin, Sheng-Hsuan

2016-01-01

Global smartphone penetration has led to unprecedented addictive behaviors. The aims of this study are to develop diagnostic criteria of smartphone addiction and to examine the discriminative ability and the validity of the diagnostic criteria. We developed twelve candidate criteria for characteristic symptoms of smartphone addiction and four criteria for functional impairment caused by excessive smartphone use. The participants consisted of 281 college students. Each participant was systematically assessed for smartphone-using behaviors by psychiatrist's structured diagnostic interview. The sensitivity, specificity, and diagnostic accuracy of the candidate symptom criteria were analyzed with reference to the psychiatrists' clinical global impression. The optimal model selection with its cutoff point of the diagnostic criteria differentiating the smartphone addicted subjects from non-addicted subjects was then determined by the best diagnostic accuracy. Six symptom criteria model with optimal cutoff point were determined based on the maximal diagnostic accuracy. The proposed smartphone addiction diagnostic criteria consisted of (1) six symptom criteria, (2) four functional impairment criteria and (3) exclusion criteria. Setting three symptom criteria as the cutoff point resulted in the highest diagnostic accuracy (84.3%), while the sensitivity and specificity were 79.4% and 87.5%, respectively. We suggested determining the functional impairment by two or more of the four domains considering the high accessibility and penetration of smartphone use. The diagnostic criteria of smartphone addiction demonstrated the core symptoms "impaired control" paralleled with substance related and addictive disorders. The functional impairment involved multiple domains provide a strict standard for clinical assessment.
Prospect of Continuous VLBI Measurement of Earth Rotation in Monitoring Geophysical Fluids

NASA Technical Reports Server (NTRS)

Chao, Benjamin F.; Ma, Chopo; Clark, Thomas

1998-01-01

Large-scale mass transports in the geophysical fluids of the Earth system excite Earth's rotational variations in both length-of-day and polar motion. The excitation process is via the conservation of angular momentum. Therefore Earth rotation observations contain information about the integrated angular momentum (consisting of both the mass term and the motion term) of the geophysical fluids, which include atmosphere, hydrosphere, mantle, and the outer and inner cores. Such global information is often important and otherwise unattainable depending on the nature of the mass transport, its magnitude and time scale. The last few years have seen great advances in VLBI measurement of Earth rotation in precision and temporal resolution. These advances have opened new. areas in geophysical fluid studies, such as oceanic tidal angular momentum, atmospheric tides, Earth librations, and rapid atmospheric angular momentum fluctuations. Precision of 10 microseconds in UTI and 200 microarcseconds in polar motion can now be achieved on hourly basis. Building upon this heritage, the multi-network geodetic VLBI project, Continuous Observation of the Rotation of the Earth (CORE), promises to further these studies and to make possible studies on elusive but tell-tale geophysical processes such as oscillatory modes in the core and in the atmosphere. Currently the early phase of CORE is underway. Within a few years into the new mellinnium, the upcoming space gravity missions (such as GRACE) will measure the temporal variations in Earth's gravitational field, thus providing complementary information to that from Earth rotation study for a better understanding of global geophysical fluid processes.
Angular analysis of the B 0 → K *0 μ + μ - decay using 3 fb-1 of integrated luminosity

NASA Astrophysics Data System (ADS)

Aaij, R.; Abellán Beteta, C.; Adeva, B.; Adinolfi, M.; Affolder, A.; Ajaltouni, Z.; Akar, S.; Albrecht, J.; Alessio, F.; Alexander, M.; Ali, S.; Alkhazov, G.; Alvarez Cartelle, P.; Alves, A. A.; Amato, S.; Amerio, S.; Amhis, Y.; An, L.; Anderlini, L.; Andreassi, G.; Andreotti, M.; Andrews, J. E.; Appleby, R. B.; Aquines Gutierrez, O.; Archilli, F.; d'Argent, P.; Artamonov, A.; Artuso, M.; Aslanides, E.; Auriemma, G.; Baalouch, M.; Bachmann, S.; Back, J. J.; Badalov, A.; Baesso, C.; Baldini, W.; Barlow, R. J.; Barschel, C.; Barsuk, S.; Barter, W.; Batozskaya, V.; Battista, V.; Bay, A.; Beaucourt, L.; Beddow, J.; Bedeschi, F.; Bediaga, I.; Bel, L. J.; Bellee, V.; Belloli, N.; Belyaev, I.; Ben-Haim, E.; Bencivenni, G.; Benson, S.; Benton, J.; Berezhnoy, A.; Bernet, R.; Bertolin, A.; Bettler, M.-O.; van Beuzekom, M.; Bifani, S.; Billoir, P.; Bird, T.; Birnkraut, A.; Bizzeti, A.; Blake, T.; Blanc, F.; Blouw, J.; Blusk, S.; Bocci, V.; Bondar, A.; Bondar, N.; Bonivento, W.; Borghi, S.; Borisyak, M.; Borsato, M.; Bowcock, T. J. V.; Bowen, E.; Bozzi, C.; Braun, S.; Britsch, M.; Britton, T.; Brodzicka, J.; Brook, N. H.; Buchanan, E.; Burr, C.; Bursche, A.; Buytaert, J.; Cadeddu, S.; Calabrese, R.; Calvi, M.; Calvo Gomez, M.; Campana, P.; Campora Perez, D.; Capriotti, L.; Carbone, A.; Carboni, G.; Cardinale, R.; Cardini, A.; Carniti, P.; Carson, L.; Carvalho Akiba, K.; Casse, G.; Cassina, L.; Castillo Garcia, L.; Cattaneo, M.; Cauet, Ch.; Cavallero, G.; Cenci, R.; Charles, M.; Charpentier, Ph.; Chefdeville, M.; Chen, S.; Cheung, S.-F.; Chiapolini, N.; Chrzaszcz, M.; Cid Vidal, X.; Ciezarek, G.; Clarke, P. E. L.; Clemencic, M.; Cliff, H. V.; Closier, J.; Coco, V.; Cogan, J.; Cogneras, E.; Cogoni, V.; Cojocariu, L.; Collazuol, G.; Collins, P.; Comerma-Montells, A.; Contu, A.; Cook, A.; Coombes, M.; Coquereau, S.; Corti, G.; Corvo, M.; Couturier, B.; Cowan, G. A.; Craik, D. C.; Crocombe, A.; Cruz Torres, M.; Cunliffe, S.; Currie, R.; D'Ambrosio, C.; Dall'Occo, E.; Dalseno, J.; David, P. N. Y.; Davis, A.; De Aguiar Francisco, O.; De Bruyn, K.; De Capua, S.; De Cian, M.; De Miranda, J. M.; De Paula, L.; De Simone, P.; Dean, C.-T.; Decamp, D.; Deckenhoff, M.; Del Buono, L.; Déléage, N.; Demmer, M.; Derkach, D.; Deschamps, O.; Dettori, F.; Dey, B.; Di Canto, A.; Di Ruscio, F.; Dijkstra, H.; Donleavy, S.; Dordei, F.; Dorigo, M.; Dosil Suárez, A.; Dovbnya, A.; Dreimanis, K.; Dufour, L.; Dujany, G.; Dungs, K.; Durante, P.; Dzhelyadin, R.; Dziurda, A.; Dzyuba, A.; Easo, S.; Egede, U.; Egorychev, V.; Eidelman, S.; Eisenhardt, S.; Eitschberger, U.; Ekelhof, R.; Eklund, L.; El Rifai, I.; Elsasser, Ch.; Ely, S.; Esen, S.; Evans, H. M.; Evans, T.; Fabianska, M.; Falabella, A.; Färber, C.; Farley, N.; Farry, S.; Fay, R.; Ferguson, D.; Fernandez Albor, V.; Ferrari, F.; Ferreira Rodrigues, F.; Ferro-Luzzi, M.; Filippov, S.; Fiore, M.; Fiorini, M.; Firlej, M.; Fitzpatrick, C.; Fiutowski, T.; Fleuret, F.; Fohl, K.; Fol, P.; Fontana, M.; Fontanelli, F.; Forshaw, D. C.; Forty, R.; Frank, M.; Frei, C.; Frosini, M.; Fu, J.; Furfaro, E.; Gallas Torreira, A.; Galli, D.; Gallorini, S.; Gambetta, S.; Gandelman, M.; Gandini, P.; Gao, Y.; García Pardiñas, J.; Garra Tico, J.; Garrido, L.; Gascon, D.; Gaspar, C.; Gauld, R.; Gavardi, L.; Gazzoni, G.; Gerick, D.; Gersabeck, E.; Gersabeck, M.; Gershon, T.; Ghez, Ph.; Gianì, S.; Gibson, V.; Girard, O. G.; Giubega, L.; Gligorov, V. V.; Göbel, C.; Golubkov, D.; Golutvin, A.; Gomes, A.; Gotti, C.; Grabalosa Gándara, M.; Graciani Diaz, R.; Granado Cardoso, L. A.; Graugés, E.; Graverini, E.; Graziani, G.; Grecu, A.; Greening, E.; Griffith, P.; Grillo, L.; Grünberg, O.; Gui, B.; Gushchin, E.; Guz, Yu.; Gys, T.; Hadavizadeh, T.; Hadjivasiliou, C.; Haefeli, G.; Haen, C.; Haines, S. C.; Hall, S.; Hamilton, B.; Han, X.; Hansmann-Menzemer, S.; Harnew, N.; Harnew, S. T.; Harrison, J.; He, J.; Head, T.; Heijne, V.; Heister, A.; Hennessy, K.; Henrard, P.; Henry, L.; Hernando Morata, J. A.; van Herwijnen, E.; Heß, M.; Hicheur, A.; Hill, D.; Hoballah, M.; Hombach, C.; Hulsbergen, W.; Humair, T.; Hushchyn, M.; Hussain, N.; Hutchcroft, D.; Hynds, D.; Idzik, M.; Ilten, P.; Jacobsson, R.; Jaeger, A.; Jalocha, J.; Jans, E.; Jawahery, A.; John, M.; Johnson, D.; Jones, C. R.; Joram, C.; Jost, B.; Jurik, N.; Kandybei, S.; Kanso, W.; Karacson, M.; Karbach, T. M.; Karodia, S.; Kecke, M.; Kelsey, M.; Kenyon, I. R.; Kenzie, M.; Ketel, T.; Khairullin, E.; Khanji, B.; Khurewathanakul, C.; Kirn, T.; Klaver, S.; Klimaszewski, K.; Kochebina, O.; Kolpin, M.; Komarov, I.; Koopman, R. F.; Koppenburg, P.; Kozeiha, M.; Kravchuk, L.; Kreplin, K.; Kreps, M.; Krokovny, P.; Kruse, F.; Krzemien, W.; Kucewicz, W.; Kucharczyk, M.; Kudryavtsev, V.; Kuonen, A. K.; Kurek, K.; Kvaratskheliya, T.; Lacarrere, D.; Lafferty, G.; Lai, A.; Lambert, D.; Lanfranchi, G.; Langenbruch, C.; Langhans, B.; Latham, T.; Lazzeroni, C.; Le Gac, R.; van Leerdam, J.; Lees, J.-P.; Lefèvre, R.; Leflat, A.; Lefrançois, J.; Lemos Cid, E.; Leroy, O.; Lesiak, T.; Leverington, B.; Li, Y.; Likhomanenko, T.; Liles, M.; Lindner, R.; Linn, C.; Lionetto, F.; Liu, B.; Liu, X.; Loh, D.; Longstaff, I.; Lopes, J. H.; Lucchesi, D.; Lucio Martinez, M.; Luo, H.; Lupato, A.; Luppi, E.; Lupton, O.; Lusiani, A.; Machefert, F.; Maciuc, F.; Maev, O.; Maguire, K.; Malde, S.; Malinin, A.; Manca, G.; Mancinelli, G.; Manning, P.; Mapelli, A.; Maratas, J.; Marchand, J. F.; Marconi, U.; Marin Benito, C.; Marino, P.; Marks, J.; Martellotti, G.; Martin, M.; Martinelli, M.; Martinez Santos, D.; Martinez Vidal, F.; Martins Tostes, D.; Massacrier, L. M.; Massafferri, A.; Matev, R.; Mathad, A.; Mathe, Z.; Matteuzzi, C.; Mauri, A.; Maurin, B.; Mazurov, A.; McCann, M.; McCarthy, J.; McNab, A.; McNulty, R.; Meadows, B.; Meier, F.; Meissner, M.; Melnychuk, D.; Merk, M.; Michielin, E.; Milanes, D. A.; Minard, M.-N.; Mitzel, D. S.; Molina Rodriguez, J.; Monroy, I. A.; Monteil, S.; Morandin, M.; Morawski, P.; Mordà, A.; Morello, M. J.; Moron, J.; Morris, A. B.; Mountain, R.; Muheim, F.; Müller, D.; Müller, J.; Müller, K.; Müller, V.; Mussini, M.; Muster, B.; Naik, P.; Nakada, T.; Nandakumar, R.; Nandi, A.; Nasteva, I.; Needham, M.; Neri, N.; Neubert, S.; Neufeld, N.; Neuner, M.; Nguyen, A. D.; Nguyen, T. D.; Nguyen-Mau, C.; Niess, V.; Niet, R.; Nikitin, N.; Nikodem, T.; Novoselov, A.; O'Hanlon, D. P.; Oblakowska-Mucha, A.; Obraztsov, V.; Ogilvy, S.; Okhrimenko, O.; Oldeman, R.; Onderwater, C. J. G.; Osorio Rodrigues, B.; Otalora Goicochea, J. M.; Otto, A.; Owen, P.; Oyanguren, A.; Palano, A.; Palombo, F.; Palutan, M.; Panman, J.; Papanestis, A.; Pappagallo, M.; Pappalardo, L. L.; Pappenheimer, C.; Parker, W.; Parkes, C.; Passaleva, G.; Patel, G. D.; Patel, M.; Patrignani, C.; Pearce, A.; Pellegrino, A.; Penso, G.; Pepe Altarelli, M.; Perazzini, S.; Perret, P.; Pescatore, L.; Petridis, K.; Petrolini, A.; Petruzzo, M.; Picatoste Olloqui, E.; Pietrzyk, B.; Pikies, M.; Pinci, D.; Pistone, A.; Piucci, A.; Playfer, S.; Plo Casasus, M.; Poikela, T.; Polci, F.; Poluektov, A.; Polyakov, I.; Polycarpo, E.; Popov, A.; Popov, D.; Popovici, B.; Potterat, C.; Price, E.; Price, J. D.; Prisciandaro, J.; Pritchard, A.; Prouve, C.; Pugatch, V.; Puig Navarro, A.; Punzi, G.; Qian, W.; Quagliani, R.; Rachwal, B.; Rademacker, J. H.; Rama, M.; Ramos Pernas, M.; Rangel, M. S.; Raniuk, I.; Rauschmayr, N.; Raven, G.; Redi, F.; Reichert, S.; dos Reis, A. C.; Renaudin, V.; Ricciardi, S.; Richards, S.; Rihl, M.; Rinnert, K.; Rives Molina, V.; Robbe, P.; Rodrigues, A. B.; Rodrigues, E.; Rodriguez Lopez, J. A.; Rodriguez Perez, P.; Roiser, S.; Romanovsky, V.; Romero Vidal, A.; Ronayne, J. W.; Rotondo, M.; Ruf, T.; Ruiz Valls, P.; Saborido Silva, J. J.; Sagidova, N.; Saitta, B.; Salustino Guimaraes, V.; Sanchez Mayordomo, C.; Sanmartin Sedes, B.; Santacesaria, R.; Santamarina Rios, C.; Santimaria, M.; Santovetti, E.; Sarti, A.; Satriano, C.; Satta, A.; Saunders, D. M.; Savrina, D.; Schael, S.; Schiller, M.; Schindler, H.; Schlupp, M.; Schmelling, M.; Schmelzer, T.; Schmidt, B.; Schneider, O.; Schopper, A.; Schubiger, M.; Schune, M.-H.; Schwemmer, R.; Sciascia, B.; Sciubba, A.; Semennikov, A.; Sergi, A.; Serra, N.; Serrano, J.; Sestini, L.; Seyfert, P.; Shapkin, M.; Shapoval, I.; Shcheglov, Y.; Shears, T.; Shekhtman, L.; Shevchenko, V.; Shires, A.; Siddi, B. G.; Silva Coutinho, R.; Silva de Oliveira, L.; Simi, G.; Sirendi, M.; Skidmore, N.; Skwarnicki, T.; Smith, E.; Smith, E.; Smith, I. T.; Smith, J.; Smith, M.; Snoek, H.; Sokoloff, M. D.; Soler, F. J. P.; Soomro, F.; Souza, D.; Souza De Paula, B.; Spaan, B.; Spradlin, P.; Sridharan, S.; Stagni, F.; Stahl, M.; Stahl, S.; Stefkova, S.; Steinkamp, O.; Stenyakin, O.; Stevenson, S.; Stoica, S.; Stone, S.; Storaci, B.; Stracka, S.; Straticiuc, M.; Straumann, U.; Sun, L.; Sutcliffe, W.; Swientek, K.; Swientek, S.; Syropoulos, V.; Szczekowski, M.; Szumlak, T.; T'Jampens, S.; Tayduganov, A.; Tekampe, T.; Tellarini, G.; Teubert, F.; Thomas, C.; Thomas, E.; van Tilburg, J.; Tisserand, V.; Tobin, M.; Todd, J.; Tolk, S.; Tomassetti, L.; Tonelli, D.; Topp-Joergensen, S.; Torr, N.; Tournefier, E.; Tourneur, S.; Trabelsi, K.; Traill, M.; Tran, M. T.; Tresch, M.; Trisovic, A.; Tsaregorodtsev, A.; Tsopelas, P.; Tuning, N.; Ukleja, A.; Ustyuzhanin, A.; Uwer, U.; Vacca, C.; Vagnoni, V.; Valenti, G.; Vallier, A.; Vazquez Gomez, R.; Vazquez Regueiro, P.; Vázquez Sierra, C.; Vecchi, S.; van Veghel, M.; Velthuis, J. J.; Veltri, M.; Veneziano, G.; Vesterinen, M.; Viaud, B.; Vieira, D.; Vieites Diaz, M.; Vilasis-Cardona, X.; Volkov, V.; Vollhardt, A.; Voong, D.; Vorobyev, A.; Vorobyev, V.; Voß, C.; de Vries, J. A.; Waldi, R.; Wallace, C.; Wallace, R.; Walsh, J.; Wang, J.; Ward, D. R.; Watson, N. K.; Websdale, D.; Weiden, A.; Whitehead, M.; Wicht, J.; Wilkinson, G.; Wilkinson, M.; Williams, M.; Williams, M. P.; Williams, M.; Williams, T.; Wilson, F. F.; Wimberley, J.; Wishahi, J.; Wislicki, W.; Witek, M.; Wormser, G.; Wotton, S. A.; Wraight, K.; Wright, S.; Wyllie, K.; Xie, Y.; Xu, Z.; Yang, Z.; Yu, J.; Yuan, X.; Yushchenko, O.; Zangoli, M.; Zavertyaev, M.; Zhang, L.; Zhang, Y.; Zhelezov, A.; Zhokhov, A.; Zhong, L.; Zhukov, V.; Zucchelli, S.

2016-02-01

An angular analysis of the B 0 → K *0(→ K + π -) μ + μ - decay is presented. The dataset corresponds to an integrated luminosity of 3.0 fb-1 of pp collision data collected at the LHCb experiment. The complete angular information from the decay is used to determine CP-averaged observables and CP asymmetries, taking account of possible contamination from decays with the K + π - system in an S-wave configuration. The angular observables and their correlations are reported in bins of q 2, the invariant mass squared of the dimuon system. The observables are determined both from an unbinned maximum likelihood fit and by using the principal moments of the angular distribution. In addition, by fitting for q 2-dependent decay amplitudes in the region 1.1 < q 2 < 6.0 GeV2/ c 4, the zero-crossing points of several angular observables are computed. A global fit is performed to the complete set of CP-averaged observables obtained from the maximum likelihood fit. This fit indicates differences with predictions based on the Standard Model at the level of 3.4 standard deviations. These differences could be explained by contributions from physics beyond the Standard Model, or by an unexpectedly large hadronic effect that is not accounted for in the Standard Model predictions. [Figure not available: see fulltext.
Angular analysis of the B o → K *oμ +μ – decay using 3 fb –1 of integrated luminosity

DOE PAGES

Aaij, R.; Abellán Beteta, C.; Adeva, B.; ...

2016-02-16

An angular analysis of the B o → K *o (→ K +π –)μ +μ – decay is presented. The dataset corresponds to an integrated luminosity of 3.0 fb –1 of pp collision data collected at the LHCb experiment. The complete angular information from the decay is used to determine CP-averaged observables and CP asymmetries, taking account of possible contamination from decays with the K +π – system in an S-wave configuration. The angular observables and their correlations are reported in bins of q 2, the invariant mass squared of the dimuon system. The observables are determined both from anmore » unbinned maximum likelihood fit and by using the principal moments of the angular distribution. In addition, by fitting for q 2 -dependent decay amplitudes in the region 1.1 < q 2 < 6.0 GeV 2/c 4, the zero-crossing points of several angular observables are computed. A global fit is performed to the complete set of CP-averaged observables obtained from the maximum likelihood fit. This fit indicates differences with predictions based on the Standard Model at the level of 3.4 standard deviations. These differences could be explained by contributions from physics beyond the Standard Model, or by an unexpectedly large hadronic effect that is not accounted for in the Standard Model predictions.« less

Influence of upstream solar wind on thermospheric flows at Jupiter

NASA Astrophysics Data System (ADS)

Yates, J. N.; Achilleos, N.; Guio, P.

2012-02-01

The coupling of Jupiter's magnetosphere and ionosphere plays a vital role in creating its auroral emissions. The strength of these emissions is dependent on the difference in speed of the rotational flows within Jupiter's high-latitude thermosphere and the planet's magnetodisc. Using an azimuthally symmetric global circulation model, we have simulated how upstream solar wind conditions affect the energy and direction of atmospheric flows. In order to simulate the effect of a varying dynamic pressure in the upstream solar wind, we calculated three magnetic field profiles representing compressed, averaged and expanded ‘middle’ magnetospheres. These profiles were then used to solve for the angular velocity of plasma in the magnetosphere. This angular velocity determines the strength of currents flowing between the ionosphere and magnetosphere. We examine the influence of variability in this current system upon the global winds and energy inputs within the Jovian thermosphere. We find that the power dissipated by Joule heating and ion drag increases by ∼190% and ∼185% from our compressed to expanded model respectively. We investigated the effect of exterior boundary conditions on our models and found that by reducing the radial current at the outer edge of the magnetodisc, we also limit the thermosphere's ability to transmit angular momentum to this region.
MESSENGER observations of transient bursts of energetic electrons in Mercury's magnetosphere.

PubMed

Ho, George C; Krimigis, Stamatios M; Gold, Robert E; Baker, Daniel N; Slavin, James A; Anderson, Brian J; Korth, Haje; Starr, Richard D; Lawrence, David J; McNutt, Ralph L; Solomon, Sean C

2011-09-30

The MESSENGER spacecraft began detecting energetic electrons with energies greater than 30 kilo-electron volts (keV) shortly after its insertion into orbit about Mercury. In contrast, no energetic protons were observed. The energetic electrons arrive as bursts lasting from seconds to hours and are most intense close to the planet, distributed in latitude from the equator to the north pole, and present at most local times. Energies can exceed 200 keV but often exhibit cutoffs near 100 keV. Angular distributions of the electrons about the magnetic field suggest that they do not execute complete drift paths around the planet. This set of characteristics demonstrates that Mercury's weak magnetic field does not support Van Allen-type radiation belts, unlike all other planets in the solar system with internal magnetic fields.
Discovery of Localized Regions of Excess 10-TeV Cosmic Rays

NASA Astrophysics Data System (ADS)

Abdo, A. A.; Allen, B.; Aune, T.; Berley, D.; Blaufuss, E.; Casanova, S.; Chen, C.; Dingus, B. L.; Ellsworth, R. W.; Fleysher, L.; Fleysher, R.; Gonzalez, M. M.; Goodman, J. A.; Hoffman, C. M.; Hüntemeyer, P. H.; Kolterman, B. E.; Lansdell, C. P.; Linnemann, J. T.; McEnery, J. E.; Mincer, A. I.; Nemethy, P.; Noyes, D.; Pretz, J.; Ryan, J. M.; Parkinson, P. M. Saz; Shoup, A.; Sinnis, G.; Smith, A. J.; Sullivan, G. W.; Vasileiou, V.; Walker, G. P.; Williams, D. A.; Yodh, G. B.

2008-11-01

The 7 year data set of the Milagro TeV observatory contains 2.2×1011 events of which most are due to hadronic cosmic rays. These data are searched for evidence of intermediate scale structure. Excess emission on angular scales of ˜10° has been found in two localized regions of unknown origin with greater than 12σ significance. Both regions are inconsistent with pure gamma-ray emission with high confidence. One of the regions has a different energy spectrum than the isotropic cosmic-ray flux at a level of 4.6σ, and it is consistent with hard spectrum protons with an exponential cutoff, with the most significant excess at ˜10TeV. Potential causes of these excesses are explored, but no compelling explanations are found.
Discovery of localized regions of excess 10-TeV cosmic rays.

PubMed

Abdo, A A; Allen, B; Aune, T; Berley, D; Blaufuss, E; Casanova, S; Chen, C; Dingus, B L; Ellsworth, R W; Fleysher, L; Fleysher, R; Gonzalez, M M; Goodman, J A; Hoffman, C M; Hüntemeyer, P H; Kolterman, B E; Lansdell, C P; Linnemann, J T; McEnery, J E; Mincer, A I; Nemethy, P; Noyes, D; Pretz, J; Ryan, J M; Parkinson, P M Saz; Shoup, A; Sinnis, G; Smith, A J; Sullivan, G W; Vasileiou, V; Walker, G P; Williams, D A; Yodh, G B

2008-11-28

The 7 year data set of the Milagro TeV observatory contains 2.2 x 10(11) events of which most are due to hadronic cosmic rays. These data are searched for evidence of intermediate scale structure. Excess emission on angular scales of approximately 10 degrees has been found in two localized regions of unknown origin with greater than 12sigma significance. Both regions are inconsistent with pure gamma-ray emission with high confidence. One of the regions has a different energy spectrum than the isotropic cosmic-ray flux at a level of 4.6sigma, and it is consistent with hard spectrum protons with an exponential cutoff, with the most significant excess at approximately 10 TeV. Potential causes of these excesses are explored, but no compelling explanations are found.
The Impact of Estimating High-Resolution Tropospheric Gradients on Multi-GNSS Precise Positioning

PubMed Central

Zhou, Feng; Li, Xingxing; Li, Weiwei; Chen, Wen; Dong, Danan; Wickert, Jens; Schuh, Harald

2017-01-01

Benefits from the modernized US Global Positioning System (GPS), the revitalized Russian GLObal NAvigation Satellite System (GLONASS), and the newly-developed Chinese BeiDou Navigation Satellite System (BDS) and European Galileo, multi-constellation Global Navigation Satellite System (GNSS) has emerged as a powerful tool not only in positioning, navigation, and timing (PNT), but also in remote sensing of the atmosphere and ionosphere. Both precise positioning and the derivation of atmospheric parameters can benefit from multi-GNSS observations. In this contribution, extensive evaluations are conducted with multi-GNSS datasets collected from 134 globally-distributed ground stations of the International GNSS Service (IGS) Multi-GNSS Experiment (MGEX) network in July 2016. The datasets are processed in six different constellation combinations, i.e., GPS-, GLONASS-, BDS-only, GPS + GLONASS, GPS + BDS, and GPS + GLONASS + BDS + Galileo precise point positioning (PPP). Tropospheric gradients are estimated with eight different temporal resolutions, from 1 h to 24 h, to investigate the impact of estimating high-resolution gradients on position estimates. The standard deviation (STD) is used as an indicator of positioning repeatability. The results show that estimating tropospheric gradients with high temporal resolution can achieve better positioning performance than the traditional strategy in which tropospheric gradients are estimated on a daily basis. Moreover, the impact of estimating tropospheric gradients with different temporal resolutions at various elevation cutoff angles (from 3° to 20°) is investigated. It can be observed that with increasing elevation cutoff angles, the improvement in positioning repeatability is decreased. PMID:28368346
The Impact of Estimating High-Resolution Tropospheric Gradients on Multi-GNSS Precise Positioning.

PubMed

Zhou, Feng; Li, Xingxing; Li, Weiwei; Chen, Wen; Dong, Danan; Wickert, Jens; Schuh, Harald

2017-04-03

Benefits from the modernized US Global Positioning System (GPS), the revitalized Russian GLObal NAvigation Satellite System (GLONASS), and the newly-developed Chinese BeiDou Navigation Satellite System (BDS) and European Galileo, multi-constellation Global Navigation Satellite System (GNSS) has emerged as a powerful tool not only in positioning, navigation, and timing (PNT), but also in remote sensing of the atmosphere and ionosphere. Both precise positioning and the derivation of atmospheric parameters can benefit from multi-GNSS observations. In this contribution, extensive evaluations are conducted with multi-GNSS datasets collected from 134 globally-distributed ground stations of the International GNSS Service (IGS) Multi-GNSS Experiment (MGEX) network in July 2016. The datasets are processed in six different constellation combinations, i.e., GPS-, GLONASS-, BDS-only, GPS + GLONASS, GPS + BDS, and GPS + GLONASS + BDS + Galileo precise point positioning (PPP). Tropospheric gradients are estimated with eight different temporal resolutions, from 1 h to 24 h, to investigate the impact of estimating high-resolution gradients on position estimates. The standard deviation (STD) is used as an indicator of positioning repeatability. The results show that estimating tropospheric gradients with high temporal resolution can achieve better positioning performance than the traditional strategy in which tropospheric gradients are estimated on a daily basis. Moreover, the impact of estimating tropospheric gradients with different temporal resolutions at various elevation cutoff angles (from 3° to 20°) is investigated. It can be observed that with increasing elevation cutoff angles, the improvement in positioning repeatability is decreased.
Features in the primordial spectrum from WMAP: A wavelet analysis

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

Shafieloo, Arman; Souradeep, Tarun; Manimaran, P.

2007-06-15

Precise measurements of the anisotropies in the cosmic microwave background enable us to do an accurate study on the form of the primordial power spectrum for a given set of cosmological parameters. In a previous paper [A. Shafieloo and T. Souradeep, Phys. Rev. D 70, 043523 (2004).], we implemented an improved (error sensitive) Richardson-Lucy deconvolution algorithm on the measured angular power spectrum from the first year of WMAP data to determine the primordial power spectrum assuming a concordance cosmological model. This recovered spectrum has a likelihood far better than a scale invariant, or, 'best fit' scale free spectra ({delta}lnL{approx_equal}25 withmore » respect to the Harrison-Zeldovich spectrum, and, {delta}lnL{approx_equal}11 with respect to the power law spectrum with n{sub s}=0.95). In this paper we use the discrete wavelet transform (DWT) to decompose the local features of the recovered spectrum individually to study their effect and significance on the recovered angular power spectrum and hence the likelihood. We show that besides the infrared cutoff at the horizon scale, the associated features of the primordial power spectrum around the horizon have a significant effect on improving the likelihood. The strong features are localized at the horizon scale.« less
Multiple Model Adaptive Attitude Control of LEO Satellite with Angular Velocity Constraints

NASA Astrophysics Data System (ADS)

Shahrooei, Abolfazl; Kazemi, Mohammad Hosein

2018-04-01

In this paper, the multiple model adaptive control is utilized to improve the transient response of attitude control system for a rigid spacecraft. An adaptive output feedback control law is proposed for attitude control under angular velocity constraints and its almost global asymptotic stability is proved. The multiple model adaptive control approach is employed to counteract large uncertainty in parameter space of the inertia matrix. The nonlinear dynamics of a low earth orbit satellite is simulated and the proposed control algorithm is implemented. The reported results show the effectiveness of the suggested scheme.
Diagnostic Studies with GLA Fields

NASA Technical Reports Server (NTRS)

Salstein, David A.

1997-01-01

Assessments of the NASA Goddard Earth Observing System-1 Data Assimilation System(GEOS-1 DAS), regarding heating rates, energetics, and angular momentum quantities were made. These diagnostics can be viewed as measures of climate variability. Comparisons with the NOAA/NCEP reanalysis system of momentum and energetics diagnostics are included. Water vapor and angular momentum are diagnosed in many models, including those of NASA, as part of the Atmospheric Model Intercomparison Project. 'Me GEOS-I and NOAA/NCEP global atmospheric angular momentum values are coherent on time scales down to about three days. Furthermore, they agree with the series of Earth angular momentum, as measured by tiny fluctuations in the rotation rate of the Earth, as variations in the length of day. The torques that effect such changes in atmospheric and Earth momentum are dominated by the influence of particular mountain systems, including the Rockies, Himalayas, and Andes, upon mountain torques on time scales shorter than about two weeks. Other project areas included collaboration with Goddard Space Flight Center to examine the impact of mountainous areas and the treatments of parameterizations on diagnoses of the atmosphere. Relevant preprints are included herein.
India plate angular velocity and contemporary deformation rates from continuous GPS measurements from 1996 to 2015.

PubMed

Jade, Sridevi; Shrungeshwara, T S; Kumar, Kireet; Choudhury, Pallabee; Dumka, Rakesh K; Bhu, Harsh

2017-09-12

We estimate a new angular velocity for the India plate and contemporary deformation rates in the plate interior and along its seismically active margins from Global Positioning System (GPS) measurements from 1996 to 2015 at 70 continuous and 3 episodic stations. A new India-ITRF2008 angular velocity is estimated from 30 GPS sites, which include stations from western and eastern regions of the plate interior that were unrepresented or only sparsely sampled in previous studies. Our newly estimated India-ITRF2008 Euler pole is located significantly closer to the plate with ~3% higher angular velocity than all previous estimates and thus predicts more rapid variations in rates and directions along the plate boundaries. The 30 India plate GPS site velocities are well fit by the new angular velocity, with north and east RMS misfits of only 0.8 and 0.9 mm/yr, respectively. India fixed velocities suggest an approximate of 1-2 mm/yr intra-plate deformation that might be concentrated along regional dislocations, faults in Peninsular India, Kachchh and Indo-Gangetic plain. Relative to our newly-defined India plate frame of reference, the newly estimated velocities for 43 other GPS sites along the plate margins give insights into active deformation along India's seismically active northern and eastern boundaries.
Classification of individual well-being scores for the determination of adverse health and productivity outcomes in employee populations.

PubMed

Shi, Yuyan; Sears, Lindsay E; Coberley, Carter R; Pope, James E

2013-04-01

Adverse health and productivity outcomes have imposed a considerable economic burden on employers. To facilitate optimal worksite intervention designs tailored to differing employee risk levels, the authors established cutoff points for an Individual Well-Being Score (IWBS) based on a global measure of well-being. Cross-sectional associations between IWBS and adverse health and productivity outcomes, including high health care cost, emergency room visits, short-term disability days, absenteeism, presenteeism, low job performance ratings, and low intentions to stay with the employer, were studied in a sample of 11,702 employees from a large employer. Receiver operating characteristics curves were evaluated to detect a single optimal cutoff value of IWBS for predicting 2 or more adverse outcomes. More granular segmentation was achieved by computing relative risks of each adverse outcome from logistic regressions accounting for sociodemographic characteristics. Results showed strong and significant nonlinear associations between IWBS and health and productivity outcomes. An IWBS of 75 was found to be the optimal single cutoff point to discriminate 2 or more adverse outcomes. Logistic regression models found abrupt reductions of relative risk also clustered at IWBS cutoffs of 53, 66, and 88, in addition to 75, which segmented employees into high, high-medium, medium, low-medium, and low risk groups. To determine validity and generalizability, cutoff values were applied in a smaller employee population (N=1853) and confirmed significant differences between risk groups across health and productivity outcomes. The reported segmentation of IWBS into discrete cohorts based on risk of adverse health and productivity outcomes should facilitate well-being comparisons and worksite interventions.
HIFiRE-5 Flight Test Preliminary Results (Postprint)

DTIC Science & Technology

2013-11-01

DMARS-R) IMU and Ashtech DG14 Global Positioning System receiver. Results show that a tripped transition occurred on the test article leading edge...Reference System (DMARS-R) IMU and Ashtech DG14 Global Positioning System receiver. Results show that a tripped transition occurred on the test...pitch angle relative to earth as measured by IMU , or flight-path elevation angle as measured by GPS or IMU , degrees  = body-fixed angular coordinate
Achieving perceptually-accurate aural telepresence

NASA Astrophysics Data System (ADS)

Henderson, Paul D.

Immersive multimedia requires not only realistic visual imagery but also a perceptually-accurate aural experience. A sound field may be presented simultaneously to a listener via a loudspeaker rendering system using the direct sound from acoustic sources as well as a simulation or "auralization" of room acoustics. Beginning with classical Wave-Field Synthesis (WFS), improvements are made to correct for asymmetries in loudspeaker array geometry. Presented is a new Spatially-Equalized WFS (SE-WFS) technique to maintain the energy-time balance of a simulated room by equalizing the reproduced spectrum at the listener for a distribution of possible source angles. Each reproduced source or reflection is filtered according to its incidence angle to the listener. An SE-WFS loudspeaker array of arbitrary geometry reproduces the sound field of a room with correct spectral and temporal balance, compared with classically-processed WFS systems. Localization accuracy of human listeners in SE-WFS sound fields is quantified by psychoacoustical testing. At a loudspeaker spacing of 0.17 m (equivalent to an aliasing cutoff frequency of 1 kHz), SE-WFS exhibits a localization blur of 3 degrees, nearly equal to real point sources. Increasing the loudspeaker spacing to 0.68 m (for a cutoff frequency of 170 Hz) results in a blur of less than 5 degrees. In contrast, stereophonic reproduction is less accurate with a blur of 7 degrees. The ventriloquist effect is psychometrically investigated to determine the effect of an intentional directional incongruence between audio and video stimuli. Subjects were presented with prerecorded full-spectrum speech and motion video of a talker's head as well as broadband noise bursts with a static image. The video image was displaced from the audio stimulus in azimuth by varying amounts, and the perceived auditory location measured. A strong bias was detectable for small angular discrepancies between audio and video stimuli for separations of less than 8 degrees for speech and less than 4 degrees with a pink noise burst. The results allow for the density of WFS systems to be selected from the required localization accuracy. Also, by exploiting the ventriloquist effect, the angular resolution of an audio rendering may be reduced when combined with spatially-accurate video.
Monitoring Global Geophysical Fluids by Space Geodesy

NASA Technical Reports Server (NTRS)

Chao, Benjamin F.; Dehant, V.; Gross, R. S.; Ray, R. D.; Salstein, D. A.; Watkins, M.

1999-01-01

Since its establishment on 1/1/1998 by the International Earth Rotation Service, the Coordinating Center for Monitoring Global Geophysical Fluids (MGGF) and its seven Special Bureaus have engaged in an effort to support and facilitate the understanding of the geophysical fluids in global geodynamics research. Mass transports in the atmosphere-hydrosphere-solid Earth-core system (the "global geophysical fluids") will cause the following geodynamic effects on a broad time scale: (1) variations in the solid Earth's rotation (in length-of-day and polar motion/nutation) via the conservation of angular momentum and effected by torques at the fluid-solid Earth interface; (2) changes in the global gravitational field according to Newton's gravitational law; and (3) motion in the center of mass of the solid Earth relative to that of the whole Earth ("geocenter") via the conservation of linear momentum. These minute signals have become observable by space geodetic techniques, primarily VLBI, SLR, GPS, and DORIS, with ever increasing precision/accuracy and temporal/spatial resolution. Each of the seven Special Bureaus within MGGF is responsible for calculations related to a specific Earth component or aspect -- Atmosphere, Ocean, Hydrology, Ocean Tides, Mantle, Core, and Gravity/Geocenter. Angular momenta and torques, gravitational coefficients, and geocenter shift will be computed for geophysical fluids based on global observational data, and from state-of-the-art models, some of which assimilate such data. The computed quantities, algorithm and data formats are standardized. The results are archived and made available to the scientific research community. This paper reports the status of the MGGF activities and current results.
Scientific Benefit of Enlarging Gravitational Wave Detector Networks

NASA Astrophysics Data System (ADS)

Chu, Qi; Wen, Linqing; Blair, David

2012-06-01

Localising the sources of gravitational waves (GWs) in the sky is crucial to observing the electromagnetic counterparts of GW sources. The localisation capability is poor by a single GW detector yet can be improved by adding more detectors to the detector network. In this paper we review recent studies on scientific benefits of global detector networks and focus on their localisation capability. We employ Wen-Chen's formula to compare this merit of current and future detector networks for localising gravitational wave bursts. We find that the addition of a new detector located in Japan, or India, or Australia will increase angular resolution 3~5 fold with respect to current LIGO-Virgo network, and that the angular resolution improvement by adding a single detector in Australia is comparable to that achieved by adding detectors in both India and Japan. A six-site network achieves a 11-fold improvement in angular resolution compared with the existing three-site network.
Geodynamic Effects of Ocean Tides: Progress and Problems

NASA Technical Reports Server (NTRS)

Richard, Ray

1999-01-01

Satellite altimetry, particularly Topex/Poseidon, has markedly improved our knowledge of global tides, thereby allowing significant progress on some longstanding problems in geodynamics. This paper reviews some of that progress. Emphasis is given to global-scale problems, particularly those falling within the mandate of the new IERS Special Bureau for Tides: angular momentum, gravitational field, geocenter motion. For this discussion I use primarily the new ocean tide solutions GOT99.2, CSR4.0, and TPXO.4 (for which G. Egbert has computed inverse-theoretic error estimates), and I concentrate on new results in angular momentum and gravity and their solid-earth implications. One example is a new estimate of the effective tidal Q at the M_2 frequency, based on combining these ocean models with tidal estimates from satellite laser ranging. Three especially intractable problems are also addressed: (1) determining long-period tides in the Arctic [large unknown effect on the inertia tensor, particularly for Mf]; (2) determining the global psi_l tide [large unknown effect on interpretations of gravimetry for the near-diurnal free wobble]; and (3) determining radiational tides [large unknown temporal variations at important frequencies]. Problems (2) and (3) are related.
An optical potential for the statically deformed actinide nuclei derived from a global spherical potential

NASA Astrophysics Data System (ADS)

Al-Rawashdeh, S. M.; Jaghoub, M. I.

2018-04-01

In this work we test the hypothesis that a properly deformed spherical optical potential, used within a channel-coupling scheme, provides a good description for the scattering data corresponding to neutron induced reactions on the heavy, statically deformed actinides and other lighter deformed nuclei. To accomplish our goal, we have deformed the Koning-Delaroche spherical global potential and then used it in a channel-coupling scheme. The ground-state is coupled to a sufficient number of inelastic rotational channels belonging to the ground-state band to ensure convergence. The predicted total cross sections, elastic and inelastic angular distributions are in good agreement with the experimental data. As a further test, we compare our results to those obtained by a global channel-coupled optical model whose parameters were obtained by fitting elastic and inelastic angular distributions in addition to total cross sections. Our results compare quite well with those obtained by the fitted, channel-coupled optical model. Below neutron incident energies of about 1MeV, our results show that scattering into the rotational excited states of the ground-state band plays a significant role in the scattering process and must be explicitly accounted for using a channel-coupling scheme.
Memory, executive, and multidomain subtle cognitive impairment: clinical and biomarker findings.

PubMed

Toledo, Jon B; Bjerke, Maria; Chen, Kewei; Rozycki, Martin; Jack, Clifford R; Weiner, Michael W; Arnold, Steven E; Reiman, Eric M; Davatzikos, Christos; Shaw, Leslie M; Trojanowski, John Q

2015-07-14

We studied the biomarker signatures and prognoses of 3 different subtle cognitive impairment (SCI) groups (executive, memory, and multidomain) as well as the subjective memory complaints (SMC) group. We studied 522 healthy controls in the Alzheimer's Disease Neuroimaging Initiative (ADNI). Cutoffs for executive, memory, and multidomain SCI were defined using participants who remained cognitively normal (CN) for 7 years. CSF Alzheimer disease (AD) biomarkers, composite and region-of-interest (ROI) MRI, and fluorodeoxyglucose-PET measures were compared in these participants. Using a stringent cutoff (fifth percentile), 27.6% of the ADNI participants were classified as SCI. Most single ROI or global-based measures were not sensitive to detect differences between groups. Only MRI-SPARE-AD (Spatial Pattern of Abnormalities for Recognition of Early AD), a quantitative MRI pattern-based global index, showed differences between all groups, excluding the executive SCI group. Atrophy patterns differed in memory SCI and SMC. The CN and the SMC groups presented a similar distribution of preclinical dementia stages. Fifty percent of the participants with executive, memory, and multidomain SCI progressed to mild cognitive impairment or dementia at 7, 5, and 2 years, respectively. Our results indicate that (1) the different SCI categories have different clinical prognoses and biomarker signatures, (2) longitudinally followed CN subjects are needed to establish clinical cutoffs, (3) subjects with SMC show a frontal pattern of brain atrophy, and (4) pattern-based analyses outperform commonly used single ROI-based neuroimaging biomarkers and are needed to detect initial stages of cognitive impairment. © 2015 American Academy of Neurology.
Optimal Cutoff Values of WHO-HPQ Presenteeism Scores by ROC Analysis for Preventing Mental Sickness Absence in Japanese Prospective Cohort

PubMed Central

Suzuki, Tomoko; Miyaki, Koichi; Sasaki, Yasuharu; Song, Yixuan; Tsutsumi, Akizumi; Kawakami, Norito; Shimazu, Akihito; Takahashi, Masaya; Inoue, Akiomi; Kurioka, Sumiko; Shimbo, Takuro

2014-01-01

Objectives Sickness absence due to mental disease in the workplace has become a global public health problem. Previous studies report that sickness presenteeism is associated with sickness absence. We aimed to determine optimal cutoff scores for presenteeism in the screening of the future absences due to mental disease. Methods A prospective study of 2195 Japanese employees from all areas of Japan was conducted. Presenteeism and depression were measured by the validated Japanese version of the World Health Organization Health and Work Performance Questionnaire (WHO-HPQ) and K6 scale, respectively. Absence due to mental disease across a 2-year follow-up was surveyed using medical certificates obtained for work absence. Socioeconomic status was measured via a self-administered questionnaire. Receiver operating curve (ROC) analysis was used to determine optimal cutoff scores for absolute and relative presenteeism in relation to the area under the curve (AUC), sensitivity, and specificity. Results The AUC values for absolute and relative presenteeism were 0.708 (95% CI, 0.618–0.797) and 0.646 (95% CI, 0.546–0.746), respectively. Optimal cutoff scores of absolute and relative presenteeism were 40 and 0.8, respectively. With multivariate adjustment, cohort participants with our proposal cutoff scores for absolute and relative presenteeism were significantly more likely to be absent due to mental disease (OR = 4.85, 95% CI: 2.20–10.73 and OR = 5.37, 95% CI: 2.42–11.93, respectively). The inclusion or exclusion of depressive symptoms (K6≥13) at baseline in the multivariate adjustment did not influence the results. Conclusions Our proposed optimal cutoff scores of absolute and relative presenteeism are 40 and 0.8, respectively. Participants who scored worse than the cutoff scores for presenteeism were significantly more likely to be absent in future because of mental disease. Our findings suggest that the utility of presenteeism in the screening of sickness absence due to mental disease would help prevent such an absence. PMID:25340520
Canadian global village reality: anthropometric surrogate cutoffs and metabolic abnormalities among Canadians of East Asian, South Asian, and European descent.

PubMed

He, Meizi; Li, E T S; Harris, Stewart; Huff, Murray W; Yau, Chun Y; Anderson, G Harvey

2010-05-01

To test the appropriateness of body mass index (BMI) and waist circumference (WC) cutoff points derived in largely white populations (ie, those of European descent) for detecting obesity-related metabolic abnormalities among East Asian and South Asian Canadians. Cross-sectional survey. Primary care and community settings in Ontario. Canadians of East Asian (n = 130), South Asian (n = 113), and European (n = 111) descent. Variables for metabolic syndromes, including BMI, WC, body fat percentage, blood pressure, lipid profile, and fasting blood glucose and insulin levels, were measured. Receiver operating characteristics curve analysis was used to generate BMI and WC cutoff points based on various criteria for metabolic syndromes. Adjusting for sex and age, East Asian Canadians had a significantly lower mean BMI (23.2 kg/m(2)) and mean WC (79.6 cm) than did those of South Asian (26.1 kg/m(2) and 90.3 cm) and European (26.5 kg/m(2) and 89.3 cm) descent (P < .05). The BMI cutoffs for an increased risk of metabolic abnormalities ranged from 23.1 to 24.4 kg/m(2) in East Asian Canadians; 26.6 to 26.8 kg/m(2) in South Asian Canadians; and 26.3 to 28.2 kg/m(2) in European Canadians. Waist circumference cutoffs for increased risk of metabolic abnormalities were relatively low in East Asian men (83.3 to 85.2 cm) and women (74.1 to 76.7 cm), compared with South Asian men (98.8 cm) and women (90.1 to 93.5 cm), as well as European men (91.6 to 95.2 cm) and women (82.8 to 88.3 cm). The BMI and WC cutoffs used for defining risk of metabolic abnormalities should be lowered for East Asian Canadians but not for South Asian Canadians. The World Health Organization ethnic-specific BMI and WC cutoffs should be used with caution, particularly with Asian migrants who have resided in Canada for a long period of time.

Body composition-derived BMI cut-offs for overweight and obesity in Indians and Creoles of Mauritius: comparison with Caucasians

PubMed Central

Hunma, S; Ramuth, H; Miles-Chan, J L; Schutz, Y; Montani, J-P; Joonas, N; Dulloo, A G

2016-01-01

Background and Aims: Global estimates of overweight and obesity prevalence are based on the World Health Organisation (WHO) body mass index (BMI) cut-off values of 25 and 30 kg m−2, respectively. To validate these BMI cut-offs for adiposity in the island population of Mauritius, we assessed the relationship between BMI and measured body fat mass in this population according to gender and ethnicity. Methods: In 175 young adult Mauritians (age 20-42 years) belonging to the two main ethnic groups—Indians (South Asian descent) and Creoles (African/Malagasy descent), body weight, height and waist circumference (WC) were measured, total body fat assessed by deuterium oxide (D2O) dilution and trunk (abdominal) fat by segmental bioimpedance analysis. Results: Compared to body fat% predicted from BMI using Caucasian-based equations, body fat% assessed by D2O dilution in Mauritians was higher by 3–5 units in Indian men and women as well as in Creole women, but not in Creole men. This gender-specific ethnic difference in body composition between Indians and Creoles is reflected in their BMI–Fat% relationships, as well as in their WC–Trunk Fat% relationships. Overall, WHO BMI cut-offs of 25 and 30 kg m−2 for overweight and obesity, respectively, seem valid only for Creole men (~24 and 29.5, respectively), but not for Creole women whose BMI cut-offs are 2–4 units lower (21–22 for overweight; 27–28 for obese) nor for Indian men and women whose BMI cut-offs are 3–4 units lower (21–22 for overweight; 26–27 for obese). Conclusions: The use of BMI cut-off points for classifying overweight and obesity need to take into account both ethnicity and gender to avoid gross adiposity status misclassification in this population known to be at high risk for type-2 diabetes and cardiovascular diseases. This is particularly of importance in obesity prevention strategies both in clinical medicine and public health. PMID:27698347
A Bayesian analysis of inflationary primordial spectrum models using Planck data

NASA Astrophysics Data System (ADS)

Santos da Costa, Simony; Benetti, Micol; Alcaniz, Jailson

2018-03-01

The current available Cosmic Microwave Background (CMB) data show an anomalously low value of the CMB temperature fluctuations at large angular scales (l < 40). This lack of power is not explained by the minimal ΛCDM model, and one of the possible mechanisms explored in the literature to address this problem is the presence of features in the primordial power spectrum (PPS) motivated by the early universe physics. In this paper, we analyse a set of cutoff inflationary PPS models using a Bayesian model comparison approach in light of the latest CMB data from the Planck Collaboration. Our results show that the standard power-law parameterisation is preferred over all models considered in the analysis, which motivates the search for alternative explanations for the observed lack of power in the CMB anisotropy spectrum.
The compensation of Gaussian curvature in developable cones is local

NASA Astrophysics Data System (ADS)

Wang, Jin; Witten, Thomas

2009-03-01

We use the angular deficit scheme[1] to determine numerically the distribution of Gaussian curvature in developable cones(d-cones)[2] formed by forcing a flat elastic sheet into a circular container so that the sheet buckles. This provides a new way to confirm the vanishing of mean-curvature[3] at the rim where the sheet touches the container. This angular deficit scheme also allows us to explore the potential role of the Gauss-Bonnet theorem in explaining the mean-curvature vanishing phenomenon. The theorem's global constraint on curvature resembles the global conditions observed to be relevant for vanishing mean curvature. However, our result suggests that the Gauss-Bonnet theorem does not explain the vanishing of mean-curvature. [1] V. Borrelli, F. Cazals, and J.-M. Morvan, Computer Aided Geometric Design 20, 319 (2003). [2] E. Cerda, S. Chaieb, F. Melo, and L. Mahadevan, Nature 401, 46 (1999). [3] T. Liang and T. A. Witten, Phys. Rev. E 73, 046604 (2006).
Mental chronometry with simple linear regression.

PubMed

Chen, J Y

1997-10-01

Typically, mental chronometry is performed by means of introducing an independent variable postulated to affect selectively some stage of a presumed multistage process. However, the effect could be a global one that spreads proportionally over all stages of the process. Currently, there is no method to test this possibility although simple linear regression might serve the purpose. In the present study, the regression approach was tested with tasks (memory scanning and mental rotation) that involved a selective effect and with a task (word superiority effect) that involved a global effect, by the dominant theories. The results indicate (1) the manipulation of the size of a memory set or of angular disparity affects the intercept of the regression function that relates the times for memory scanning with different set sizes or for mental rotation with different angular disparities and (2) the manipulation of context affects the slope of the regression function that relates the times for detecting a target character under word and nonword conditions. These ratify the regression approach as a useful method for doing mental chronometry.
Investigating sensitivity, specificity, and area under the curve of the Clinical COPD Questionnaire, COPD Assessment Test, and Modified Medical Research Council scale according to GOLD using St George's Respiratory Questionnaire cutoff 25 (and 20) as reference.

PubMed

Tsiligianni, Ioanna G; Alma, Harma J; de Jong, Corina; Jelusic, Danijel; Wittmann, Michael; Schuler, Michael; Schultz, Konrad; Kollen, Boudewijn J; van der Molen, Thys; Kocks, Janwillem Wh

2016-01-01

In the GOLD (Global initiative for chronic Obstructive Lung Disease) strategy document, the Clinical COPD Questionnaire (CCQ), COPD Assessment Test (CAT), or modified Medical Research Council (mMRC) scale are recommended for the assessment of symptoms using the cutoff points of CCQ ≥1, CAT ≥10, and mMRC scale ≥2 to indicate symptomatic patients. The current study investigates the criterion validity of the CCQ, CAT and mMRC scale based on a reference cutoff point of St George's Respiratory Questionnaire (SGRQ) ≥25, as suggested by GOLD, following sensitivity and specificity analysis. In addition, areas under the curve (AUCs) of the CCQ, CAT, and mMRC scale were compared using two SGRQ cutoff points (≥25 and ≥20). Two data sets were used: study A, 238 patients from a pulmonary rehabilitation program; and study B, 101 patients from primary care. Receiver-operating characteristic (ROC) curves were used to assess the correspondence between the recommended cutoff points of the questionnaires. Sensitivity, specificity, and AUC scores for cutoff point SGRQ ≥25 were: study A, 0.99, 0.43, and 0.96 for CCQ ≥1, 0.92, 0.48, and 0.89 for CAT ≥10, and 0.68, 0.91, and 0.91 for mMRC ≥2; study B, 0.87, 0.77, and 0.9 for CCQ ≥1, 0.76, 0.73, and 0.82 for CAT ≥10, and 0.21, 1, and 0.81 for mMRC ≥2. Sensitivity, specificity, and AUC scores for cutoff point SGRQ ≥20 were: study A, 0.99, 0.73, and 0.99 for CCQ ≥1, 0.91, 0.73, and 0.94 for CAT ≥10, and 0.66, 0.95, and 0.94 for mMRC ≥2; study B, 0.8, 0.89, and 0.89 for CCQ ≥1, 0.69, 0.78, and 0.8 for CAT ≥10, and 0.18, 1, and 0.81 for mMRC ≥2. Based on data from these two different samples, this study showed that the suggested cutoff point for the SGRQ (≥25) did not seem to correspond well with the established cutoff points of the CCQ or CAT scales, resulting in low specificity levels. The correspondence with the mMRC scale seemed satisfactory, though not optimal. The SGRQ threshold of ≥20 corresponded slightly better than SGRQ ≥25, recently suggested by GOLD 2015, with the established cutoff points for the CCQ, CAT, and mMRC scale.
Extra-tropical QBO signals in angular momentum and wave forcing

NASA Technical Reports Server (NTRS)

Baldwin, Mark P.; Tung, Ka Kit

1994-01-01

Although the period of the equatorial stratospheric quasi-biennal oscillation (QBO) is approximately 30 months, quasi-biennial modulation of the extratropical annual cycle may be expected to produce additional spectral peaks at approximately to produce additional spectral peaks at approximately 8.6 and 20 months in the extratropics. Using Northern Hemisphere data for 1964-78 and global data for 1978-93 it is shown that these spectral peaks are robust in both angular momentum and Eliassen-Palm flux divergence. This spectral signature represents a circulation anomaly in both hemispheres, and implies a dynamical origin to the previously observed similar spectral peaks in column ozone in the extratropics.
REVIEWS OF TOPICAL PROBLEMS: Global phase-stable radiointerferometric systems

NASA Astrophysics Data System (ADS)

Dravskikh, A. F.; Korol'kov, Dimitrii V.; Pariĭskiĭ, Yu N.; Stotskiĭ, A. A.; Finkel'steĭn, A. M.; Fridman, P. A.

1981-12-01

We discuss from a unitary standpoint the possibility of building a phase-stable interferometric system with very long baselines that operate around the clock with real-time data processing. The various problems involved in the realization of this idea are discussed: the methods of suppression of instrumental and tropospheric phase fluctuations, the methods for constructing two-dimensional images and determining the coordinates of radio sources with high angular resolution, and the problem of the optimal structure of the interferometric system. We review in detail the scientific problems from the various branches of natural science (astrophysics, cosmology, geophysics, geodynamics, astrometry, etc.) whose solution requires superhigh angular resolution.
Theoretical issues on the spontaneous rotation of axisymmetric plasmas

NASA Astrophysics Data System (ADS)

Coppi, B.; Zhou, T.

2014-09-01

An extensive series of experiments have confirmed that the observed ‘spontaneous rotation’ phenomenon in axisymmetric plasmas is related to the confinement properties of these plasmas and connected to the excitation of collective modes associated with these properties (Coppi 2000 18th IAEA Fusion Energy Conf. (Sorrento, Italy, 2000) THP 1/17, www-pub.iaea.org/MTCD/publications/PDF/csp_008c/html/node343.htm and Coppi 2002 Nucl. Fusion 42 1). In particular, radially localized modes can extract angular momentum from the plasma column from which they grow while the background plasma has to recoil in the direction opposite to that of the mode phase velocity. In the case of the excitation of the plasma modes at the edge, the loss of their angular momentum can be connected to the directed particle ejection to the surrounding medium. The recoil angular momentum is then redistributed inside the plasma column mainly by the combination of an effective viscous diffusion and an inward angular momentum transport velocity that is connected, for instance, to ion temperature gradient (ITG) driven modes. The linear and quasi-linear theories of the collisionless trapped electron modes and of the toroidal ITG driven modes are re-examined in the context of their influence on angular momentum transport. Internal modes that produce magnetic reconnection and are electromagnetic in nature, acquire characteristic phase velocity directions in high temperature regimes and become relevant to the ‘generation’ of angular momentum. The drift-tearing mode, the ‘complex’ reconnecting mode and the m0 = 1 internal mode belong to this category, the last mode acquiring different features depending on the strength of its driving factor. Toroidal velocity profiles that reproduce the experimental observations are obtained considering a global angular momentum balance equation that includes the localized sources associated with the excited internal electrostatic and electromagnetic modes besides the appropriate diffusive and the inward angular momentum transparent terms.
Classification of Individual Well-Being Scores for the Determination of Adverse Health and Productivity Outcomes in Employee Populations

PubMed Central

Sears, Lindsay E.; Coberley, Carter R.; Pope, James E.

2013-01-01

Abstract Adverse health and productivity outcomes have imposed a considerable economic burden on employers. To facilitate optimal worksite intervention designs tailored to differing employee risk levels, the authors established cutoff points for an Individual Well-Being Score (IWBS) based on a global measure of well-being. Cross-sectional associations between IWBS and adverse health and productivity outcomes, including high health care cost, emergency room visits, short-term disability days, absenteeism, presenteeism, low job performance ratings, and low intentions to stay with the employer, were studied in a sample of 11,702 employees from a large employer. Receiver operating characteristics curves were evaluated to detect a single optimal cutoff value of IWBS for predicting 2 or more adverse outcomes. More granular segmentation was achieved by computing relative risks of each adverse outcome from logistic regressions accounting for sociodemographic characteristics. Results showed strong and significant nonlinear associations between IWBS and health and productivity outcomes. An IWBS of 75 was found to be the optimal single cutoff point to discriminate 2 or more adverse outcomes. Logistic regression models found abrupt reductions of relative risk also clustered at IWBS cutoffs of 53, 66, and 88, in addition to 75, which segmented employees into high, high-medium, medium, low-medium, and low risk groups. To determine validity and generalizability, cutoff values were applied in a smaller employee population (N=1853) and confirmed significant differences between risk groups across health and productivity outcomes. The reported segmentation of IWBS into discrete cohorts based on risk of adverse health and productivity outcomes should facilitate well-being comparisons and worksite interventions. (Population Health Management 2013;16:90–98) PMID:23013034
Modified Cut-Off Value of the Urine Protein-To-Creatinine Ratio Is Helpful for Identifying Patients at High Risk for Chronic Kidney Disease: Validation of the Revised Japanese Guideline.

PubMed

Yamamoto, Hiroyuki; Yamamoto, Kyoko; Yoshida, Katsumi; Shindoh, Chiyohiko; Takeda, Kyoko; Monden, Masami; Izumo, Hiroko; Niinuma, Hiroyuki; Nishi, Yutaro; Niwa, Koichiro; Komatsu, Yasuhiro

2015-11-01

Chronic kidney disease (CKD) is a global public health issue, and strategies for its early detection and intervention are imperative. The latest Japanese CKD guideline recommends that patients without diabetes should be classified using the urine protein-to-creatinine ratio (PCR) instead of the urine albumin-to-creatinine ratio (ACR); however, no validation studies are available. This study aimed to validate the PCR-based CKD risk classification compared with the ACR-based classification and to explore more accurate classification methods. We analyzed two previously reported datasets that included diabetic and/or cardiovascular patients who were classified into early CKD stages. In total, 860 patients (131 diabetic patients and 729 cardiovascular patients, including 193 diabetic patients) were enrolled. We assessed the CKD risk classification of each patient according to the estimated glomerular filtration rate and the ACR-based or PCR-based classification. The use of the cut-off value recommended in the current guideline (PCR 0.15 g/g creatinine) resulted in risk misclassification rates of 26.0% and 16.6% for the two datasets. The misclassification was primarily caused by underestimation. Moderate to substantial agreement between each classification was achieved: Cohen's kappa, 0.56 (95% confidence interval, 0.45-0.69) and 0.72 (0.67-0.76) in each dataset, respectively. To improve the accuracy, we tested various candidate PCR cut-off values, showing that a PCR cut-off value of 0.08-0.10 g/g creatinine resulted in improvement in the misclassification rates and kappa values. Modification of the PCR cut-off value would improve its efficacy to identify high-risk populations who will benefit from early intervention.
The DAS28-ESR cutoff value necessary to achieve remission under the new Boolean-based remission criteria in patients receiving tocilizumab.

PubMed

Hirabayashi, Yasuhiko; Ishii, Tomonori

2013-01-01

To seek the cutoff value of the 28-joint disease activity score using erythrocyte sedimentation rate (DAS28-ESR) that is necessary to achieve remission under the new Boolean-based criteria, we analyzed the data for 285 patients with rheumatoid arthritis registered between May 2008 and November 2009 by the Michinoku Tocilizumab Study Group and observed for 1 year after receiving tocilizumab (TCZ) in real clinical practice. Remission rates under the DAS28-ESR criteria and the Boolean criteria were assessed every 6 months after the first TCZ dose. The DAS28-ESR cutoff value necessary to achieve remission under the new criteria was analyzed by receiver operating characteristic (ROC) analysis. Data were analyzed using last observation carried forward. After 12 months of TCZ use, remission was achieved in 164 patients (57.5 %) by DAS28-ESR and 71 patients (24.9 %) under the new criteria for clinical trials. CRP levels scarcely affected remission rates, and the difference between remission rates defined by DAS28-ESR and by the new criteria was mainly due to patient global assessment (PGA). Improvement of PGA was inversely related to disease duration. ROC analysis revealed that the DAS28-ESR cutoff value necessary to predict remission under the new criteria for clinical trials was 1.54, with a sensitivity of 88.7 %, specificity of 85.5 %, positive predictive value of 67.0 %, and negative predictive value of 95.8 %. A DAS28-ESR cutoff value of 1.54 may be reasonable to predict achievement of remission under the new Boolean-based criteria for clinical trials in patients receiving TCZ.
Testing the woman abuse screening tool to identify intimate partner violence in Indonesia.

PubMed

Iskandar, Livia; Braun, Kathryn L; Katz, Alan R

2015-04-01

Intimate Partner Violence (IPV) is a global public health problem. IPV prevalence in Indonesia has been estimated to be less than 1%, based on reported cases. It is likely that IPV prevalence is underreported in Indonesia, as it is in many other countries. Screening for IPV has been found to increase IPV identification, but no screening tools are in use in Indonesia. The aim of this study was to test the translated Woman Abuse Screening Tool (WAST) for detecting IPV in Indonesia. The WAST was tested against a diagnostic interview by a trained psychologist on 240 women attending two Primary Health Centers in Jakarta. IPV prevalence and the reliability, sensitivity, and specificity of the WAST were estimated. Prevalence of IPV by diagnostic interview was 36.3%, much higher than published estimates. The most common forms of IPV identified were psychological (85%) and physical abuse (24%). Internal reliability of the WAST was high (α = .801). A WAST score of 13 (out of 24) is the recommended cutoff for identifying IPV, but only 17% of the Indonesian sample scored 13 or higher. Test sensitivity of the WAST with a cutoff score of 13 was only 41.9%, with a specificity of 96.8%. With a cutoff score of 10, the sensitivity improved to 84.9%, while the specificity decreased to 61.0%. Use of the WAST with a cutoff score of 10 provides good sensitivity and reasonable specificity and would provide a much-needed screening tool for use in Indonesia. Although a lower cutoff would yield a greater proportion of false positives, most of the true cases would be identified, increasing the possibility that women experiencing abuse would receive needed assistance. © The Author(s) 2014.
Global-local duality in eternal inflation

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

Bousso, Raphael; Yang, I-S.

2009-12-15

We prove that the light-cone time cutoff on the multiverse defines the same probabilities as a causal patch with initial conditions in the longest-lived metastable vacuum. This establishes the equivalence of two measures of eternal inflation which naively appear very different (though both are motivated by holography). The duality can be traced to an underlying geometric relation which we identify.
Global Longitudinal Strain Using Speckle-Tracking Echocardiography as a Mortality Predictor in Sepsis: A Systematic Review.

PubMed

Vallabhajosyula, Saraschandra; Rayes, Hamza A; Sakhuja, Ankit; Murad, Mohammad Hassan; Geske, Jeffrey B; Jentzer, Jacob C

2018-01-01

The data on speckle-tracking echocardiography (STE) in patients with sepsis are limited. This systematic review from 1975 to 2016 included studies in adults and children evaluating cardiovascular dysfunction in sepsis, severe sepsis, and septic shock utilizing STE for systolic global longitudinal strain (GLS). The primary outcome was short- or long-term mortality. Given the significant methodological and statistical differences between published studies, combining the data using meta-analysis methods was not appropriate. A total of 120 studies were identified, with 5 studies (561 patients) included in the final analysis. All studies were prospective observational studies using the 2001 criteria for defining sepsis. Three studies demonstrated worse systolic GLS to be associated with higher mortality, whereas 2 did not show a statistically significant association. Various cutoffs between -10% and -17% were used to define abnormal GLS across studies. This systematic review revealed that STE may predict mortality in patients with sepsis; however, the strength of evidence is low due to heterogeneity in study populations, GLS technologies, cutoffs, and timing of STE. Further dedicated studies are needed to understand the optimal application of STE in patients with sepsis.
A conservative spectral method for the Boltzmann equation with anisotropic scattering and the grazing collisions limit

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

Gamba, Irene M.; ICES, The University of Texas at Austin, 201 E. 24th St., Stop C0200, Austin, TX 78712; Haack, Jeffrey R.

2014-08-01

We present the formulation of a conservative spectral method for the Boltzmann collision operator with anisotropic scattering cross-sections. The method is an extension of the conservative spectral method of Gamba and Tharkabhushanam [17,18], which uses the weak form of the collision operator to represent the collisional term as a weighted convolution in Fourier space. The method is tested by computing the collision operator with a suitably cut-off angular cross section and comparing the results with the solution of the Landau equation. We analytically study the convergence rate of the Fourier transformed Boltzmann collision operator in the grazing collisions limit tomore » the Fourier transformed Landau collision operator under the assumption of some regularity and decay conditions of the solution to the Boltzmann equation. Our results show that the angular singularity which corresponds to the Rutherford scattering cross section is the critical singularity for which a grazing collision limit exists for the Boltzmann operator. Additionally, we numerically study the differences between homogeneous solutions of the Boltzmann equation with the Rutherford scattering cross section and an artificial cross section, which give convergence to solutions of the Landau equation at different asymptotic rates. We numerically show the rate of the approximation as well as the consequences for the rate of entropy decay for homogeneous solutions of the Boltzmann equation and Landau equation.« less
Mission Concept for the Single Aperture Far-Infrared (SAFIR) Observatory

NASA Technical Reports Server (NTRS)

Benford, Dominic J.; Amato, Michael J.; Mather, John C.; Moseley, S. Harvey, Jr.

2004-01-01

We have developed a preliminary but comprehensive mission concept for SAFIR, as a 10 m-class far-infrared and submillimeter observatory that would begin development later in this decade to meet the needs outlined above. Its operating temperature (< or = 4K) and instrument complement would be optimized to reach the natural sky confusion limit in the far-infrared with diffraction-limited performance down to at least the atmospheric cutoff, lambda > or approx. 40 microns. This would provide a point source sensitivity improvement of several orders of magnitude over that of the Spitzer Space Telescope (previously SIRTF) or the Herschel Space Observatory. Additionally, it would have an angular resolution 12 times finer than that of Spitzer and three times finer than Herschel. This sensitivity and angular resolution are necessary to perform imaging and spectroscopic studies of individual galaxies in the early universe. We have considered many aspects of the SAFIR mission, including the telescope technology (optical design, materials, and packaging), detector needs and technologies, cooling method and required technology developments, attitude and pointing, power systems, launch vehicle, and mission operations. The most challenging requirements for this mission are operating temperature and aperture size of the telescope, and the development of detector arrays. SAFIR can take advantage of much of the technology under development for JWST, but with much less stringent requirements on optical accuracy.
Exposure of wild boar to Mycobacterium tuberculosis complex in France since 2000 is consistent with the distribution of bovine tuberculosis outbreaks in cattle.

PubMed

Richomme, Céline; Boadella, Mariana; Courcoul, Aurélie; Durand, Benoît; Drapeau, Antoine; Corde, Yannick; Hars, Jean; Payne, Ariane; Fediaevsky, Alexandre; Boschiroli, María Laura

2013-01-01

The Eurasian wild boar (Sus scrofa) is increasingly considered as a relevant actor in the epidemiology of animal tuberculosis (TB). Therefore, monitoring TB in wild boar becomes a key tool for establishing comprehensive control schemes for this disease. To estimate the exposure of free living wild boar to Mycobacterium tuberculosis complex (MTC) in France, a bovine-purified protein derivative based ELISA was used to test 2,080 archived serum samples of hunter-harvested animals in 58 French "départements". Two cut-off values were used for diagnostic interpretation: 0.2, recommended by the manufacturer (specificity: 96.43%; sensitivity: 72.6%), and 0.5 (specificity: 100%; sensitivity: 64%). During the same period, at the 0.2 cut-off, global true seroprevalence was 5.9% (IC95%: 4.3%-7.7%) and 76% of the sampled "départements" had seropositive wild boar, including seven cattle TB-free "départements. At the 0.5 cut-off, global true seroprevalence was 2.2% (IC95%: 1.5-3.2) and positive wild boar belonged to 21% of the "départements". All but one of these positive "départements" had reported at least one cattle TB outbreak since 2000. A good consistence between seropositive wild boar and TB outbreaks in cattle was found, especially at the 0.5 cut-off value (the mean distance to the nearest cattle TB outbreak was 13 km and 27 km for seropositive and seronegative wild boar, respectively; P<0.05). The use of an ELISA to detect MTC antibodies in wild boar has permitted the description of the geographic distribution of MTC contact in wild boar in France. Our results suggest that the ELISA could be used as a first screening tool to conduct TB surveillance in wild boar at a population level. High-risk wild boar populations (e.g. overabundant) could be tested and if identified positive by ELISA they should be surveyed in detail by combining pathology and culture.
Exposure of Wild Boar to Mycobacterium tuberculosis Complex in France since 2000 Is Consistent with the Distribution of Bovine Tuberculosis Outbreaks in Cattle

PubMed Central

Richomme, Céline; Boadella, Mariana; Courcoul, Aurélie; Durand, Benoît; Drapeau, Antoine; Corde, Yannick; Hars, Jean; Payne, Ariane; Fediaevsky, Alexandre; Boschiroli, María Laura

2013-01-01

The Eurasian wild boar (Sus scrofa) is increasingly considered as a relevant actor in the epidemiology of animal tuberculosis (TB). Therefore, monitoring TB in wild boar becomes a key tool for establishing comprehensive control schemes for this disease. To estimate the exposure of free living wild boar to Mycobacterium tuberculosis complex (MTC) in France, a bovine-purified protein derivative based ELISA was used to test 2,080 archived serum samples of hunter-harvested animals in 58 French “départements”. Two cut-off values were used for diagnostic interpretation: 0.2, recommended by the manufacturer (specificity: 96.43%; sensitivity: 72.6%), and 0.5 (specificity: 100%; sensitivity: 64%). During the same period, at the 0.2 cut-off, global true seroprevalence was 5.9% (IC95%: 4.3%-7.7%) and 76% of the sampled “départements” had seropositive wild boar, including seven cattle TB-free “départements. At the 0.5 cut-off, global true seroprevalence was 2.2% (IC95%: 1.5-3.2) and positive wild boar belonged to 21% of the “départements”. All but one of these positive “départements” had reported at least one cattle TB outbreak since 2000. A good consistence between seropositive wild boar and TB outbreaks in cattle was found, especially at the 0.5 cut-off value (the mean distance to the nearest cattle TB outbreak was 13km and 27km for seropositive and seronegative wild boar, respectively; P<0.05). The use of an ELISA to detect MTC antibodies in wild boar has permitted the description of the geographic distribution of MTC contact in wild boar in France. Our results suggest that the ELISA could be used as a first screening tool to conduct TB surveillance in wild boar at a population level. High-risk wild boar populations (e.g. overabundant) could be tested and if identified positive by ELISA they should be surveyed in detail by combining pathology and culture. PMID:24167584
General relativistic satellite astrometry. II. Modeling parallax and proper motion

NASA Astrophysics Data System (ADS)

de Felice, F.; Bucciarelli, B.; Lattanzi, M. G.; Vecchiato, A.

2001-07-01

The non-perturbative general relativistic approach to global astrometry introduced by de Felice et al. (\\cite{defetal}) is here extended to account for the star motions on the Schwarzschild celestial sphere. A new expression of the observables, i.e. angular distances among stars, is provided, which takes into account the effects of parallax and proper motions. This dynamical model is then tested on an end-to-end simulation of the global astrometry mission GAIA. The results confirm the findings of our earlier work, which applied to the case of a static (angular coordinates only) sphere. In particular, measurements of large arcs among stars (each measurement good to ~ 100 mu arcsec, as expected for V ~ 17 mag stars) repeated over an observing period comparable to the mission lifetime foreseen for GAIA, can be modeled to yield estimates of positions, parallaxes, and annual proper motions good to ~ 15 mu arcsec. This second round of experiments confirms, within the limitations of the simulation and the assumptions of the current relativistic model, that the space-born global astrometry initiated with Hipparcos can be pushed down to the 10-5 arcsec accuracy level proposed with the GAIA mission. Finally, the simplified case we have solved can be used as reference for testing the limiting behavior of more realistic models as they become available.
Monte Carlo simulations on marker grouping and ordering.

PubMed

Wu, J; Jenkins, J; Zhu, J; McCarty, J; Watson, C

2003-08-01

Four global algorithms, maximum likelihood (ML), sum of adjacent LOD score (SALOD), sum of adjacent recombinant fractions (SARF) and product of adjacent recombinant fraction (PARF), and one approximation algorithm, seriation (SER), were used to compare the marker ordering efficiencies for correctly given linkage groups based on doubled haploid (DH) populations. The Monte Carlo simulation results indicated the marker ordering powers for the five methods were almost identical. High correlation coefficients were greater than 0.99 between grouping power and ordering power, indicating that all these methods for marker ordering were reliable. Therefore, the main problem for linkage analysis was how to improve the grouping power. Since the SER approach provided the advantage of speed without losing ordering power, this approach was used for detailed simulations. For more generality, multiple linkage groups were employed, and population size, linkage cutoff criterion, marker spacing pattern (even or uneven), and marker spacing distance (close or loose) were considered for obtaining acceptable grouping powers. Simulation results indicated that the grouping power was related to population size, marker spacing distance, and cutoff criterion. Generally, a large population size provided higher grouping power than small population size, and closely linked markers provided higher grouping power than loosely linked markers. The cutoff criterion range for achieving acceptable grouping power and ordering power differed for varying cases; however, combining all situations in this study, a cutoff criterion ranging from 50 cM to 60 cM was recommended for achieving acceptable grouping power and ordering power for different cases.

Comparison of commercial ELISA tests for the detection of Toxoplasma antibodies in the meat juice of naturally infected pigs.

PubMed

Felin, Elina; Näreaho, Anu; Fredriksson-Ahomaa, Maria

2017-04-30

Toxoplasmosis is a globally distributed protozoal zoonosis. Pigs are considered an important reservoir of Toxoplasma gondii and pork a major infection source of human toxoplasmosis. ELISA methods are commonly used diagnostic tools for detecting Toxoplasma infections. They are also used for slaughterhouse-based serological monitoring of toxoplasmosis in pigs to identify positive farms. The methods used are non-standardised with varying sensitivity and specificity. In our study, four commercial ELISA tests for the detection of Toxoplasma antibodies in the meat juice of slaughter pigs were compared with a modified agglutination test (MAT) as a reference. The cut-off values of the ELISA tests provided by the manufacturer varied between 0.20 and 0.50, and clearly influenced prevalence. The sensitivity of tests I, II and III varied between 96.4 and 78.6. Sensitivity was unacceptably low (3.6) for test IV (cut-off=0.30). Tests I, II and III had the highest accuracy and the best agreement with the reference test when a cut-off of 0.30 was used. Test II and III showed very good agreement (K=0.92 and 0.84, respectively) with the MAT. A very strong correlation (Pearson correlation >0.89) was observed between the S/P values of tests I, II and III. Our results demonstrate that the test and cut-off value used influence the results of the apparent seroprevalence studies. Copyright © 2017 Elsevier B.V. All rights reserved.
Variations in the rotation of the earth

NASA Astrophysics Data System (ADS)

Carter, W. E.; Robertson, D. S.; Pettey, J. E.; Tapley, B. D.; Schutz, B. E.; Eanes, R. J.; Miao, L.

Variations in the earth's rotation (UTI) and length of day have been tracked at the submillisecond level by astronomical radio interferometry and laser ranging to the LAGEOS satellite. Three years of regular measurements reveal complex patterns of variations including UTI fluctuations as large as 5 milliseconds in a few weeks. Comparison of the observed changes in length of day with variations in the global atmospheric angular momentum indicates that the dominant cause of changes in the earth's spin rate, on time scales from a week to several years, is the exchange of angular momentum between the atmosphere and the mantle. The unusually intense El Nino of 1982-1983 was marked by a strong peak in the length of day.
Geophysical excitation of LOD/UT1 estimated from the output of the global circulation models of the atmosphere - ERA-40 reanalysis and of the ocean - OMCT

NASA Astrophysics Data System (ADS)

Korbacz, A.; Brzeziński, A.; Thomas, M.

2008-04-01

We use new estimates of the global atmospheric and oceanic angular momenta (AAM, OAM) to study the influence on LOD/UT1. The AAM series was calculated from the output fields of the atmospheric general circulation model ERA-40 reanalysis. The OAM series is an outcome of global ocean model OMCT simulation driven by global fields of the atmospheric parameters from the ERA- 40 reanalysis. The excitation data cover the period between 1963 and 2001. Our calculations concern atmospheric and oceanic effects in LOD/UT1 over the periods between 20 days and decades. Results are compared to those derived from the alternative AAM/OAM data sets.
Annual and seasonal tornado activity in the United States and the global wind oscillation

NASA Astrophysics Data System (ADS)

Moore, Todd W.

2018-06-01

Previous studies have searched for relationships between tornado activity and atmospheric teleconnections to provide insight on the relationship between tornadoes, their environments, and larger scale patterns in the climate system. Knowledge of these relationships is practical because it can improve seasonal and sub-seasonal predictions of tornado probability and, therefore, help mitigate tornado-related losses. This study explores the relationships between the annual and seasonal tornado activity in the United States and the Global Wind Oscillation. Time series herein show that phases of the Global Wind Oscillation, and atmospheric angular momentum anomalies, vary over a period of roughly 20-25 years. Rank correlations indicate that tornado activity is weakly correlated with phases 2, 3, and 4 (positive) and 6, 7, and 8 (negative) of the Global Wind Oscillation in winter, spring, and fall. The correlation is not as clear in summer or at the annual scale. Non-parametric Mann-Whitney U tests indicate that winters and springs with more phase 2, 3, and 4 and fewer phase 6, 7, and 8 days tend to have more tornadoes. Lastly, logistic regression models indicate that winters and springs with more phase 2, 3, and 4 days have greater likelihoods of having more than normal tornado activity. Combined, these analyses suggest that seasons with more low atmospheric angular momentum days, or phase 2, 3, and 4 days, tend to have greater tornado activity than those with fewer days, and that this relationship is most evident in winter and spring.
Annual and seasonal tornado activity in the United States and the global wind oscillation

NASA Astrophysics Data System (ADS)

Moore, Todd W.

2017-08-01

Previous studies have searched for relationships between tornado activity and atmospheric teleconnections to provide insight on the relationship between tornadoes, their environments, and larger scale patterns in the climate system. Knowledge of these relationships is practical because it can improve seasonal and sub-seasonal predictions of tornado probability and, therefore, help mitigate tornado-related losses. This study explores the relationships between the annual and seasonal tornado activity in the United States and the Global Wind Oscillation. Time series herein show that phases of the Global Wind Oscillation, and atmospheric angular momentum anomalies, vary over a period of roughly 20-25 years. Rank correlations indicate that tornado activity is weakly correlated with phases 2, 3, and 4 (positive) and 6, 7, and 8 (negative) of the Global Wind Oscillation in winter, spring, and fall. The correlation is not as clear in summer or at the annual scale. Non-parametric Mann-Whitney U tests indicate that winters and springs with more phase 2, 3, and 4 and fewer phase 6, 7, and 8 days tend to have more tornadoes. Lastly, logistic regression models indicate that winters and springs with more phase 2, 3, and 4 days have greater likelihoods of having more than normal tornado activity. Combined, these analyses suggest that seasons with more low atmospheric angular momentum days, or phase 2, 3, and 4 days, tend to have greater tornado activity than those with fewer days, and that this relationship is most evident in winter and spring.
A microscopic derivation of nuclear collective rotation-vibration model and its application to nuclei

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

Gulshani, P., E-mail: matlap@bell.net

We derive a microscopic version of the successful phenomenological hydrodynamic model of Bohr-Davydov-Faessler-Greiner for collective rotation-vibration motion of an axially symmetric deformed nucleus. The derivation is not limited to small oscillation amplitude. The nuclear Schrodinger equation is canonically transformed to collective co-ordinates, which is then linearized using a constrained variational method. The associated constraints are imposed on the wavefunction rather than on the particle co-ordinates. The approach yields three self-consistent, time-reversal invariant, cranking-type Schrodinger equations for the rotation-vibration and intrinsic motions, and a self-consistency equation. For harmonic oscillator mean-field potentials, these equations are solved in closed forms for excitation energy,more » cut-off angular momentum, and other nuclear properties for the ground-state rotational band in some deformed nuclei. The results are compared with measured data.« less
Large-Scale Corrections to the CMB Anisotropy from Asymptotic de Sitter Mode

NASA Astrophysics Data System (ADS)

Sojasi, A.

2018-01-01

In this study, large-scale effects from asymptotic de Sitter mode on the CMB anisotropy are investigated. Besides the slow variation of the Hubble parameter onset of the last stage of inflation, the recent observational constraints from Planck and WMAP on spectral index confirm that the geometry of the universe can not be pure de Sitter in this era. Motivated by these evidences, we use this mode to calculate the power spectrum of the CMB anisotropy on the large scale. It is found that the CMB spectrum is dependent on the index of Hankel function ν which in the de Sitter limit ν → 3/2, the power spectrum reduces to the scale invariant result. Also, the result shows that the spectrum of anisotropy is dependent on angular scale and slow-roll parameter and these additional corrections are swept away by a cutoff scale parameter H ≪ M ∗ < M P .
Superresolved digital in-line holographic microscopy for high-resolution lensless biological imaging

NASA Astrophysics Data System (ADS)

Micó, Vicente; Zalevsky, Zeev

2010-07-01

Digital in-line holographic microscopy (DIHM) is a modern approach capable of achieving micron-range lateral and depth resolutions in three-dimensional imaging. DIHM in combination with numerical imaging reconstruction uses an extremely simplified setup while retaining the advantages provided by holography with enhanced capabilities derived from algorithmic digital processing. We introduce superresolved DIHM incoming from time and angular multiplexing of the sample spatial frequency information and yielding in the generation of a synthetic aperture (SA). The SA expands the cutoff frequency of the imaging system, allowing submicron resolutions in both transversal and axial directions. The proposed approach can be applied when imaging essentially transparent (low-concentration dilutions) and static (slow dynamics) samples. Validation of the method for both a synthetic object (U.S. Air Force resolution test) to quantify the resolution improvement and a biological specimen (sperm cells biosample) are reported showing the generation of high synthetic numerical aperture values working without lenses.
DOE Office of Scientific and Technical Information (OSTI.GOV)

Bolding, Simon R.; Cleveland, Mathew Allen; Morel, Jim E.

In this paper, we have implemented a new high-order low-order (HOLO) algorithm for solving thermal radiative transfer problems. The low-order (LO) system is based on the spatial and angular moments of the transport equation and a linear-discontinuous finite-element spatial representation, producing equations similar to the standard S 2 equations. The LO solver is fully implicit in time and efficiently resolves the nonlinear temperature dependence at each time step. The high-order (HO) solver utilizes exponentially convergent Monte Carlo (ECMC) to give a globally accurate solution for the angular intensity to a fixed-source pure-absorber transport problem. This global solution is used tomore » compute consistency terms, which require the HO and LO solutions to converge toward the same solution. The use of ECMC allows for the efficient reduction of statistical noise in the Monte Carlo solution, reducing inaccuracies introduced through the LO consistency terms. Finally, we compare results with an implicit Monte Carlo code for one-dimensional gray test problems and demonstrate the efficiency of ECMC over standard Monte Carlo in this HOLO algorithm.« less
A High-Order Low-Order Algorithm with Exponentially Convergent Monte Carlo for Thermal Radiative Transfer

DOE PAGES

Bolding, Simon R.; Cleveland, Mathew Allen; Morel, Jim E.

2016-10-21

In this paper, we have implemented a new high-order low-order (HOLO) algorithm for solving thermal radiative transfer problems. The low-order (LO) system is based on the spatial and angular moments of the transport equation and a linear-discontinuous finite-element spatial representation, producing equations similar to the standard S 2 equations. The LO solver is fully implicit in time and efficiently resolves the nonlinear temperature dependence at each time step. The high-order (HO) solver utilizes exponentially convergent Monte Carlo (ECMC) to give a globally accurate solution for the angular intensity to a fixed-source pure-absorber transport problem. This global solution is used tomore » compute consistency terms, which require the HO and LO solutions to converge toward the same solution. The use of ECMC allows for the efficient reduction of statistical noise in the Monte Carlo solution, reducing inaccuracies introduced through the LO consistency terms. Finally, we compare results with an implicit Monte Carlo code for one-dimensional gray test problems and demonstrate the efficiency of ECMC over standard Monte Carlo in this HOLO algorithm.« less
Bilinear modeling and nonlinear estimation

NASA Technical Reports Server (NTRS)

Dwyer, Thomas A. W., III; Karray, Fakhreddine; Bennett, William H.

1989-01-01

New methods are illustrated for online nonlinear estimation applied to the lateral deflection of an elastic beam on board measurements of angular rates and angular accelerations. The development of the filter equations, together with practical issues of their numerical solution as developed from global linearization by nonlinear output injection are contrasted with the usual method of the extended Kalman filter (EKF). It is shown how nonlinear estimation due to gyroscopic coupling can be implemented as an adaptive covariance filter using off-the-shelf Kalman filter algorithms. The effect of the global linearization by nonlinear output injection is to introduce a change of coordinates in which only the process noise covariance is to be updated in online implementation. This is in contrast to the computational approach which arises in EKF methods arising by local linearization with respect to the current conditional mean. Processing refinements for nonlinear estimation based on optimal, nonlinear interpolation between observations are also highlighted. In these methods the extrapolation of the process dynamics between measurement updates is obtained by replacing a transition matrix with an operator spline that is optimized off-line from responses to selected test inputs.
Global risk of big earthquakes has not recently increased.

PubMed

Shearer, Peter M; Stark, Philip B

2012-01-17

The recent elevated rate of large earthquakes has fueled concern that the underlying global rate of earthquake activity has increased, which would have important implications for assessments of seismic hazard and our understanding of how faults interact. We examine the timing of large (magnitude M≥7) earthquakes from 1900 to the present, after removing local clustering related to aftershocks. The global rate of M≥8 earthquakes has been at a record high roughly since 2004, but rates have been almost as high before, and the rate of smaller earthquakes is close to its historical average. Some features of the global catalog are improbable in retrospect, but so are some features of most random sequences--if the features are selected after looking at the data. For a variety of magnitude cutoffs and three statistical tests, the global catalog, with local clusters removed, is not distinguishable from a homogeneous Poisson process. Moreover, no plausible physical mechanism predicts real changes in the underlying global rate of large events. Together these facts suggest that the global risk of large earthquakes is no higher today than it has been in the past.
Global risk of big earthquakes has not recently increased

PubMed Central

Shearer, Peter M.; Stark, Philip B.

2012-01-01

The recent elevated rate of large earthquakes has fueled concern that the underlying global rate of earthquake activity has increased, which would have important implications for assessments of seismic hazard and our understanding of how faults interact. We examine the timing of large (magnitude M≥7) earthquakes from 1900 to the present, after removing local clustering related to aftershocks. The global rate of M≥8 earthquakes has been at a record high roughly since 2004, but rates have been almost as high before, and the rate of smaller earthquakes is close to its historical average. Some features of the global catalog are improbable in retrospect, but so are some features of most random sequences—if the features are selected after looking at the data. For a variety of magnitude cutoffs and three statistical tests, the global catalog, with local clusters removed, is not distinguishable from a homogeneous Poisson process. Moreover, no plausible physical mechanism predicts real changes in the underlying global rate of large events. Together these facts suggest that the global risk of large earthquakes is no higher today than it has been in the past. PMID:22184228
On the Boltzmann Equation with Stochastic Kinetic Transport: Global Existence of Renormalized Martingale Solutions

NASA Astrophysics Data System (ADS)

Punshon-Smith, Samuel; Smith, Scott

2018-02-01

This article studies the Cauchy problem for the Boltzmann equation with stochastic kinetic transport. Under a cut-off assumption on the collision kernel and a coloring hypothesis for the noise coefficients, we prove the global existence of renormalized (in the sense of DiPerna/Lions) martingale solutions to the Boltzmann equation for large initial data with finite mass, energy, and entropy. Our analysis includes a detailed study of weak martingale solutions to a class of linear stochastic kinetic equations. This study includes a criterion for renormalization, the weak closedness of the solution set, and tightness of velocity averages in {{L}1}.
Ion exhaust distributions and reconnection location with Magnetospheric Multiscale and global MHD test particles

NASA Astrophysics Data System (ADS)

Broll, J. M.; Fuselier, S. A.; Trattner, K. J.; Steven, P. M.; Burch, J. L.; Giles, B. L.

2017-12-01

Magnetic reconnection at Earth's dayside magnetopause is an essential process in magnetospheric physics. Under southward IMF conditions, reconnection occurs along a thin ribbon across the dayside magnetopause. The location of this ribbon has been studied extensively in terms of global optimization of quantities like reconnecting field energy or magnetic shear, but with expected errors of 1-2 Earth radii these global models give limited context for cases where an observation is near the reconnection line. Building on previous results, which established the cutoff contour method for locating reconnection using in-situ velocity measurements, we examine the effects of MHD-scale waves on reconnection exhaust distributions. We use a test particle exhaust distribution propagated through a globamagnetohydrodynamics model fields and compare with Magnetospheric Multiscale observations of reconnection exhaust.
Optimal boundary regularity for a singular Monge-Ampère equation

NASA Astrophysics Data System (ADS)

Jian, Huaiyu; Li, You

2018-06-01

In this paper we study the optimal global regularity for a singular Monge-Ampère type equation which arises from a few geometric problems. We find that the global regularity does not depend on the smoothness of domain, but it does depend on the convexity of the domain. We introduce (a , η) type to describe the convexity. As a result, we show that the more convex is the domain, the better is the regularity of the solution. In particular, the regularity is the best near angular points.
Meso-Scale and Small-Scale Interactions on Global Climate. Volume II. Radiation Transport Effects on Global Climate

DTIC Science & Technology

1975-02-28

max this peak , which varies substantially over Az = a A0 = 1 , r max we pick an angular increment Ae = T5— o 2 a max 2-72...22°, as into the main diffraction peak . This effect if. en- tirely missed by an equi"alent sphere model. The error incurred by assumption (7...minimize the sum of squares, we pick Q so that this expression is as negative as possible (if it is never negative for 0 ^ 0 £ 1, we are already
Earth rotation and ENSO events: combined excitation of interannual LOD variations by multiscale atmospheric oscillations

NASA Astrophysics Data System (ADS)

Zheng, Dawei; Ding, Xiaoli; Zhou, Yonghong; Chen, Yongqi

2003-03-01

Time series of the length of day characterizing the rate of Earth rotation, the atmospheric angular momentum and the Southern Oscillation Index from 1962 to 2000 are used to reexamine the relationships between the ENSO events and the changes in the length of day, as well as the global atmospheric angular momentum. Particular attention is given to the different effects of the 1982-1983 and 1997-1998 ENSO events on the variations of Earth rotation. The combined effects of multiscale atmospheric oscillations (seasonal, quasi-biennial and ENSO time scales) on the anomalous variations of the interannual rates of Earth rotation are revealed in this paper by studying the wavelet spectra of the data series.
How little pain and disability do patients with low back pain have to experience to feel that they have recovered?

PubMed Central

Maher, Christopher G.; Herbert, Robert D.; Hancock, Mark J.; Hush, Julia M.; Smeets, Robert J.

2010-01-01

Epidemiological and clinical studies of people with low back pain (LBP) commonly measure the incidence of recovery. The pain numerical rating scale (NRS), scores from 0 to 10, and Roland Morris disability questionnaire (RMDQ), scores from 0 to 24, are two instruments often used to define recovery. On both scales higher scores indicate greater severity. There is no consensus, however, on the cutoff scores on these scales that classify people as having recovered. The aim of this study was to determine which cutoff scores most accurately classify those who had recovered from LBP. Subjects from four clinical studies were categorized as ‘recovered’ or ‘unrecovered’ according to their self-rating on a global perceived effect scale. Odd ratios were calculated for scores of 0, 1, 2, 3 and 4 on the NRS and RMDQ to predict perceived recovery. Scores of 0 on the NRS and ≤2 on the RMDQ most accurately identify patients who consider themselves completely recovered. The diagnostic odds ratio (OR) for predicting recovery was 43.9 for a score of 0 on the NRS and 17.6 for a score of ≤2 on the RMDQ. There was no apparent effect of LBP duration or length of follow-up period on the optimal cutoff score. OR for the NRS were generally higher than those for RMDQ. Cutoffs of 0 on the NRS and 2 on the RMDQ most accurately classify subjects as recovered from LBP. Subjects consider pain more than disability when determining their recovery status. PMID:20229120
Quantifying entanglement of rotor chains using basis truncation: Application to dipolar endofullerene peapods.

PubMed

Halverson, Tom; Iouchtchenko, Dmitri; Roy, Pierre-Nicholas

2018-02-21

We propose a variational approach for the calculation of the quantum entanglement entropy of assemblies of rotating dipolar molecules. A basis truncation scheme based on the total angular momentum quantum number is proposed. The method is tested on hydrogen fluoride (HF) molecules confined in C 60 fullerene cages themselves trapped in a nanotube to form a carbon peapod. The rotational degrees of freedom of the HF molecules and dipolar interactions between neighboring molecules are considered in our model Hamiltonian. Both screened and unscreened dipoles are simulated and results are obtained for the ground state and one excited state that is expected to be accessible via a far-infrared collective excitation. The effect of basis truncation on energetic and entanglement properties is examined and discussed in terms of size extensivity. It is empirically found that for unscreened dipoles, a total angular momentum cutoff that increases linearly with the number of rotors is required in order to obtain proper system size scaling of the chemical potential and entanglement entropy. Recent experiments [A. Krachmalnicoff et al., Nat. Chem. 8, 953 (2016)] suggest substantial screening of the HF dipole moment, so much smaller basis sets are required to obtain converged results in this realistic case. Static correlation functions are also computed and are shown to decay much quicker in the case of screened dipoles. Our variational results are also used to test the accuracy of perturbative and pairwise ansatz treatments.

Evidence of a truncated spectrum in the angular correlation function of the cosmic microwave background

NASA Astrophysics Data System (ADS)

Melia, F.; López-Corredoira, M.

2018-03-01

Aim. The lack of large-angle correlations in the fluctuations of the cosmic microwave background (CMB) conflicts with predictions of slow-roll inflation. But while probabilities (≲0.24%) for the missing correlations disfavour the conventional picture at ≳3σ, factors not associated with the model itself may be contributing to the tension. Here we aim to show that the absence of large-angle correlations is best explained with the introduction of a non-zero minimum wave number kmin for the fluctuation power spectrum P(k). Methods: We assumed that quantum fluctuations were generated in the early Universe with a well-defined power spectrum P(k), although with a cut-off kmin ≠ 0. We then re-calculated the angular correlation function of the CMB and compared it with Planck observations. Results: The Planck 2013 data rule out a zero kmin at a confidence level exceeding 8σ. Whereas purely slow-roll inflation would have stretched all fluctuations beyond the horizon, producing a P(k) with kmin = 0 - and therefore strong correlations at all angles - a kmin ≠ 0 would signal the presence of a maximum wavelength at the time (tdec) of decoupling. This argues against the basic inflationary paradigm, and perhaps even suggests non-inflationary alternatives, for the origin and growth of perturbations in the early Universe. In at least one competing cosmology, the Rh = ct universe, the inferred kmin corresponds to the gravitational radius at tdec.
Quantitative in vivo optical tomography of cancer progression & vasculature development in adult zebrafish

PubMed Central

Kumar, Sunil; Lockwood, Nicola; Ramel, Marie-Christine; Correia, Teresa; Ellis, Matthew; Alexandrov, Yuriy; Andrews, Natalie; Patel, Rachel; Bugeon, Laurence; Dallman, Margaret J.; Brandner, Sebastian; Arridge, Simon; Katan, Matilda; McGinty, James; Frankel, Paul; French, Paul M.W.

2016-01-01

We describe a novel approach to study tumour progression and vasculature development in vivo via global 3-D fluorescence imaging of live non-pigmented adult zebrafish utilising angularly multiplexed optical projection tomography with compressive sensing (CS-OPT). This “mesoscopic” imaging method bridges a gap between established ~μm resolution 3-D fluorescence microscopy techniques and ~mm-resolved whole body planar imaging and diffuse tomography. Implementing angular multiplexing with CS-OPT, we demonstrate the in vivo global imaging of an inducible fluorescently labelled genetic model of liver cancer in adult non-pigmented zebrafish that also present fluorescently labelled vasculature. In this disease model, addition of a chemical inducer (doxycycline) drives expression of eGFP tagged oncogenic K-RASV12 in the liver of immune competent animals. We show that our novel in vivo global imaging methodology enables non-invasive quantitative imaging of the development of tumour and vasculature throughout the progression of the disease, which we have validated against established methods of pathology including immunohistochemistry. We have also demonstrated its potential for longitudinal imaging through a study of vascular development in the same zebrafish from early embryo to adulthood. We believe that this instrument, together with its associated analysis and data management tools, constitute a new platform for in vivo cancer studies and drug discovery in zebrafish disease models. PMID:27259259
Sustaining Action and Optimizing Entropy: Coupling Efficiency for Energy and the Sustainability of Global Ecosystems

ERIC Educational Resources Information Center

Rose, Michael T.; Crossan, Angus N.; Kennedy, Ivan R.

2008-01-01

Consideration of the property of action is proposed to provide a more meaningful definition of efficient energy use and sustainable production in ecosystems. Action has physical dimensions similar to angular momentum, its magnitude varying with mass, spatial configuration and relative motion. In this article, the relationship of action to…
Global and regional axial ocean angular momentum signals and length-of-day variations (1985-1996)

NASA Astrophysics Data System (ADS)

Ponte, Rui M.; Stammer, Detlef

2000-07-01

Changes in ocean angular momentum M about the polar axis are related to fluctuations in zonal currents (relative component Mr) and latitudinal shifts in mass (planetary component MΩ). Output from a 1° ocean model is used to calculate global Mr, MΩ, and M time series at 5 day intervals for the period January 1985 to April 1996. The annual cycle in Mr, MΩ, and M is larger than the semiannual cycle, and MΩ amplitudes are nearly twice those of Mr. Year-to-year modulation of the seasonal cycle is present, but interannual variability is weak. The spectrum of M is red (background slope between ω-1 and ω-2) at subseasonal periods, implying a white or blue spectrum for the external torque on the ocean. Comparisons with previous studies indicate the importance of direct atmospheric forcing in inducing subseasonal M signals, relative to instabilities and other internal sources of rapid oceanic signals. Regional angular momentum estimates show that seasonal variability tends to be larger at low latitudes, but many local maxima exist because of the spatial structure of zonal current and mass variability. At seasonal timescales, latitudes ~20°S-10°N contribute substantial variability to MΩ, while signals in Mr can be traced to Antarctic Circumpolar Current transports and associated circulation. Variability in M is found to be small when compared with similar time series for the atmosphere and the solid Earth, but ocean signals are significantly coherent with atmosphere-solid Earth residuals, implying a measurable oceanic impact on length-of-day variations.
Modeling spatial tuning of adaptation of the angular vestibulo-ocular reflex

PubMed Central

Yakushin, Sergei B.

2012-01-01

Gain adaptation of the yaw angular vestibular ocular reflex (aVOR) induced in side-down positions has gravity-independent (global) and -dependent (localized) components. When the head oscillation angles are small during adaptation, localized gain changes are maximal in the approximate position of adaptation. Concurrently, polarization vectors of canal–otolith vestibular neurons adapt their orientations during these small-angle adaptation paradigms. Whether there is orientation adaptation with large amplitude head oscillations, when the head is not localized to a specific position, is unknown. Yaw aVOR gains were decreased by oscillating monkeys about a yaw axis in a side-down position in a subject–stationary visual surround for 2 h. Amplitudes of head oscillation ranged from 15° to 180°. The yaw aVOR gain was tested in darkness at 0.5 Hz, with small angles of oscillation (±15°) while upright and in tilted positions. The peak value of the gain change was highly tuned for small angular oscillations during adaptation and significantly broadened with larger oscillation angles during adaptation. When the orientation of the polarization vectors associated with the gravity-dependent component of the neural network model was adapted toward the direction of gravity, it predicted the localized learning for small angles and the broadening when the orientation adaptation was diminished. The model-based analysis suggests that the otolith orientation adaptation plays an important role in the localized behavior of aVOR as a function of gravity and in regulating the relationship between global and localized adaptation. PMID:22660376
Atmospheric and oceanic excitation of decadal-scale Earth orientation variations

NASA Astrophysics Data System (ADS)

Gross, Richard S.; Fukumori, Ichiro; Menemenlis, Dimitris

2005-09-01

The contribution of atmospheric wind and surface pressure and oceanic current and bottom pressure variations during 1949-2002 to exciting changes in the Earth's orientation on decadal timescales is investigated using an atmospheric angular momentum series computed from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis project and an oceanic angular momentum series computed from a near-global ocean model that was forced by surface fluxes from the NCEP/NCAR reanalysis project. Not surprisingly, since decadal-scale variations in the length of day are caused mainly by interactions between the mantle and core, the effect of the atmosphere and oceans is found to be only about 14% of that observed. More surprisingly, it is found that the effect of atmospheric and oceanic processes on decadal-scale changes in polar motion is also only about 20% (x component) and 38% (y component) of that observed. Therefore redistribution of mass within the atmosphere and oceans does not appear to be the main cause of the Markowitz wobble. It is also found that on timescales between 10 days and 4 years the atmospheric and oceanic angular momentum series used here have very little skill in explaining Earth orientation variations before the mid to late 1970s. This is attributed to errors in both the Earth orientation observations prior to 1976 when measurements from the accurate space-geodetic techniques became available and to errors in the modeled atmospheric fields prior to 1979 when the satellite era of global weather observing systems began.
Localization accuracy of compact binary coalescences detected by the third-generation gravitational-wave detectors and implication for cosmology

NASA Astrophysics Data System (ADS)

Zhao, Wen; Wen, Linqing

2018-03-01

We use the Fisher information matrix to investigate the angular resolution and luminosity distance uncertainty for coalescing binary neutron stars (BNSs) and neutron star-black hole binaries (NSBHs) detected by the third-generation (3G) gravitational-wave (GW) detectors. Our study focuses on an individual 3G detector and a network of up to four 3G detectors at different locations including the United States, Europe, China, and Australia for the proposed Einstein Telescope (ET) and Cosmic Explorer (CE) detectors. In particular, we examine the effect of the Earth's rotation, as GW signals from BNS and low-mass NSBH systems could be hours long for 3G detectors. In this case, an individual detector can be effectively treated as a detector network with long baselines formed by the trajectory of the detector as it rotates with the Earth. Therefore, a single detector or two-detector networks could also be used to localize the GW sources effectively. We find that a time-dependent antenna beam-pattern function can help better localize BNS and NSBH sources, especially edge-on ones. The medium angular resolution for one ET-D detector is around 150 deg2 for BNSs at a redshift of z =0.1 , which improves rapidly with a decreasing low-frequency cutoff flow in sensitivity. The medium angular resolution for a network of two CE detectors in the United States and Europe, respectively, is around 20 deg2 at z =0.2 for the simulated BNS and NSBH samples. While for a network of two ET-D detectors, the similar angular resolution can be achieved at a much higher redshift of z =0.5 . The angular resolution of a network of three detectors is mainly determined by the baselines between detectors regardless of the CE or ET detector type. The medium angular resolution of BNS for a network of three detectors of the ET-D or CE type in the United States, Europe, and Australia is around 10 deg2 at z =2 . We discuss the implications of our results for multimessenger astronomy and, in particular, for using GW sources as independent tools to constrain the Hubble constant H0, the deceleration parameter q0, and the equation-of-state (EoS) of dark energy. We find that, in general, if 10 BNSs or NSBHs at z =0.1 with known redshifts are detected by 3G networks consisting of two ET-like detectors, H0 can be measured with an accuracy of 0.9%. If 1000 face-on BNSs at z <2 are detected with known redshifts, we are able to achieve Δ q0=0.002 for the deceleration parameter, or Δ w0=0.03 and Δ wa=0.2 for EoS of dark energy, respectively.
Precise Selenodetic Coordinate System on Artificial Light Refers

NASA Astrophysics Data System (ADS)

Bagrov, Alexander; Pichkhadze, Konstantin M.; Sysoev, Valentin

Historically a coordinate system for the Moon was established on the base of telescopic observations from the Earth. As the angular resolution of Earth-to-Space telescopic observations is limited by Earth atmosphere, and is ordinary worse then 1 ang. second, the mean accuracy of selenodetic coordinates is some angular minutes, which corresponds to errors about 900 meters for positions of lunar objects near center of visible lunar disk, and at least twice more when objects are near lunar poles. As there are no Global Positioning System nor any astronomical observation instruments on the Moon, we proposed to use an autonomous light beacon on the Luna-Globe landing module to fix its position on the surface of the moon ant to use it as refer point for fixation of spherical coordinates system for the Moon. The light beacon is designed to be surely visible by orbiting probe TV-camera. As any space probe has its own stars-orientation system, there is not a problem to calculate a set of directions to the beacon and to the referent stars in probe-centered coordinate system during flight over the beacon. Large number of measured angular positions and time of each observation will be enough to calculate both orbital parameters of the probe and selenodetic coordinates of the beacon by methods of geodesy. All this will allow fixing angular coordinates of any feature of lunar surface in one global coordinate system, referred to the beacon. The satellite’s orbit plane contains ever the center mass of main body, so if the beacon will be placed closely to a lunar pole, we shall determine pole point position of the Moon with accuracy tens times better then it is known now. When angular accuracy of self-orientation by stars of the orbital module of Luna-Glob mission will be 6 angular seconds, then being in circular orbit with height of 200 km the on-board TV-camera will allow calculation of the beacon position as well as 6" corresponding to spatial resolution of the camera. It mean that coordinates of the beacon will be determined with accuracy not worse then 6 meters on the lunar surface. Much more accuracy can be achieved if orbital probe will use as precise angular measurer as optical interferometer. The limiting accuracy of proposed method is far above any reasonable level, because it may be sub-millimeter one. Theoretical analysis shows that for achievement of 1-meter accuracy of coordinate measuring over lunar globe it will be enough to disperse over it surface some 60 light beacons. Designed by Lavochkin Association light beacon is autonomous one, and it will work at least 10 years, so coordinate frame of any other lunar mission could use established selenodetic coordinates during this period. The same approach may be used for establishing Martial coordinates system.
The global rotating scalar field vacuum on anti-de Sitter space-time

NASA Astrophysics Data System (ADS)

Kent, Carl; Winstanley, Elizabeth

2015-01-01

We consider the definition of the global vacuum state of a quantum scalar field on n-dimensional anti-de Sitter space-time as seen by an observer rotating about the polar axis. Since positive (or negative) frequency scalar field modes must have positive (or negative) Klein-Gordon norm respectively, we find that the only sensible choice of positive frequency corresponds to positive frequency as seen by a static observer. This means that the global rotating vacuum is identical to the global nonrotating vacuum. For n ≥ 4, if the angular velocity of the rotating observer is smaller than the inverse of the anti-de Sitter radius of curvature, then modes with positive Klein-Gordon norm also have positive frequency as seen by the rotating observer. We comment on the implications of this result for the construction of global rotating thermal states.
Weighing in on the hidden Asian American obesity epidemic.

PubMed

Yi, Stella S; Kwon, Simona C; Wyatt, Laura; Islam, Nadia; Trinh-Shevrin, Chau

2015-04-01

According to national estimates, obesity prevalence is lower in Asian Americans compared to other racial/ethnic groups, but this low prevalence may be misleading for three reasons. First, a lower body mass index (BMI) cutoff as proposed by the World Health Organization may be more appropriate to use in Asian populations. However, evidence is limited to substantiate the potential costs and burden of adopting these cutoffs. Increasing BMI in Asians (as in other racial/ethnic groups) should be considered across the spectrum of BMI, with a minimum awareness of these lower cutoffs among healthcare researchers. Second, the need for disaggregated data across Asian American subgroups is illustrated by the higher obesity (and diabetes) prevalence estimates observed in South Asian Americans. Third, prevalence of obesity should be placed in the larger context of immigration and globalization through cross-national comparisons and examination of acculturation-related factors. However these types of studies and collection of salient variables are not routinely performed. Data from a metropolitan area where many Asian Americans settle is presented as a case study to illustrate these points. Clear evidence that incorporates these three considerations is necessary for program planning and resource allocation for obesity-related disparities in this rapidly growing and diverse population. Copyright © 2015 Elsevier Inc. All rights reserved.
Retrieval of BRDF/Albedo by the Angular and Spectral Kernel Driven Model with Global Soil and Leaf Optical Database

NASA Astrophysics Data System (ADS)

Zhang, Y.; Wen, J.; Xiao, Q.; You, D.

2016-12-01

Operational algorithms for land surface BRDF/Albedo products are mainly developed from kernel-driven model, combining atmospherically corrected, multidate, multiband surface reflectance to extract BRDF parameters. The Angular and Spectral Kernel Driven model (ASK model), which incorporates the component spectra as a priori knowledge, provides a potential way to make full use of the multi-sensor data with multispectral information and accumulated observations. However, the ASK model is still not feasible for global BRDF/Albedo inversions due to the lack of sufficient field measurements of component spectra at the large scale. This research outlines a parameterization scheme on the component spectra for global scale BRDF/Albedo inversions in the frame of ASK. The parameter γ(λ) can be derived from the ratio of the leaf reflectance and soil reflectance, supported by globally distributed soil spectral library, ANGERS and LOPEX leaf optical properties database. To consider the intrinsic variability in both the land cover and spectral dimension, the mean and standard deviation of γ(λ) for 28 soil units and 4 leaf types in seven MODIS bands were calculated, with a world soil map used for global BRDF/Albedo products retrieval. Compared to the retrievals from BRF datasets simulated by the PROSAIL model, ASK model shows an acceptable accuracy on the parameterization strategy, with the RMSE 0.007 higher at most than inversion by true component spectra. The results indicate that the classification on ratio contributed to capture the spectral characteristics in BBRDF/Albedo retrieval, whereas the ratio range should be controlled within 8% in each band. Ground-based measurements in Heihe river basin were used to validate the accuracy of the improved ASK model, and the generated broadband albedo products shows good agreement with in situ data, which suggests that the improvement of the component spectra on the ASK model has potential for global scale BRDF/Albedo inversions.
Slumped glass optics with interfacing ribs for high angular resolution x-ray astronomy: a progress report

NASA Astrophysics Data System (ADS)

Civitani, M.; Basso, S.; Brizzolari, C.; Ghigo, M.; Pareschi, G.; Salmaso, B.; Spiga, D.; Vecchi, G.; Breunig, E.; Burwitz, V.; Hartner, G. D.; Menz, B.

2015-09-01

The Slumped Glass Optics technology, developed at INAF/OAB since a few years, is becoming a competitive solution for the realization of the future X-ray telescopes with a very large collecting area, as e.g. the proposed Athena, with more than 2 m2 effective area at 1 keV and with a high angular resolution (5'' HEW). The developed technique is based on modular elements, named X-ray Optical Units (XOUs), made of several layers of thin foils of glass, previously formed by direct hot slumping in cylindrical configuration, and then stacked in a Wolter-I configuration, through interfacing ribs. The achievable global angular resolution of the optics relies on the surface shape accuracy of the slumped foils, on the smoothness of the mirror surfaces and on the correct integration and co-alignment of the mirror segments achieved with a dedicated Integration Machine (IMA). In this paper we provide an update of the project development, reporting on the last results achieved. In particular, we will present the results obtained with full illumination X-ray tests for the last developed prototypes.
Attitude Representations for Kalman Filtering

NASA Technical Reports Server (NTRS)

Markley, F. Landis; Bauer, Frank H. (Technical Monitor)

2001-01-01

The four-component quaternion has the lowest dimensionality possible for a globally nonsingular attitude representation, it represents the attitude matrix as a homogeneous quadratic function, and its dynamic propagation equation is bilinear in the quaternion and the angular velocity. The quaternion is required to obey a unit norm constraint, though, so Kalman filters often employ a quaternion for the global attitude estimate and a three-component representation for small errors about the estimate. We consider these mixed attitude representations for both a first-order Extended Kalman filter and a second-order filter, as well for quaternion-norm-preserving attitude propagation.
Heat transport in Rayleigh-Bénard convection and angular momentum transport in Taylor-Couette flow: a comparative study

NASA Astrophysics Data System (ADS)

Brauckmann, Hannes J.; Eckhardt, Bruno; Schumacher, Jörg

2017-03-01

Rayleigh-Bénard convection and Taylor-Couette flow are two canonical flows that have many properties in common. We here compare the two flows in detail for parameter values where the Nusselt numbers, i.e. the thermal transport and the angular momentum transport normalized by the corresponding laminar values, coincide. We study turbulent Rayleigh-Bénard convection in air at Rayleigh number Ra=107 and Taylor-Couette flow at shear Reynolds number ReS=2×104 for two different mean rotation rates but the same Nusselt numbers. For individual pairwise related fields and convective currents, we compare the probability density functions normalized by the corresponding root mean square values and taken at different distances from the wall. We find one rotation number for which there is very good agreement between the mean profiles of the two corresponding quantities temperature and angular momentum. Similarly, there is good agreement between the fluctuations in temperature and velocity components. For the heat and angular momentum currents, there are differences in the fluctuations outside the boundary layers that increase with overall rotation and can be related to differences in the flow structures in the boundary layer and in the bulk. The study extends the similarities between the two flows from global quantities to local quantities and reveals the effects of rotation on the transport.
Global rotation has high sensitivity in ACL lesions within stress MRI.

PubMed

Espregueira-Mendes, João; Andrade, Renato; Leal, Ana; Pereira, Hélder; Skaf, Abdala; Rodrigues-Gomes, Sérgio; Oliveira, J Miguel; Reis, Rui L; Pereira, Rogério

2017-10-01

This study aims to objectively compare side-to-side differences of P-A laxity alone and coupled with rotatory laxity within magnetic resonance imaging, in patients with total anterior cruciate ligament (ACL) rupture. This prospective study enrolled sixty-one patients with signs and symptoms of unilateral total anterior cruciate ligament rupture, which were referred to magnetic resonance evaluation with simultaneous instrumented laxity measurements. Sixteen of those patients were randomly selected to also have the contralateral healthy knee laxity profile tested. Images were acquired for the medial and lateral tibial plateaus without pressure, with postero-anterior translation, and postero-anterior translation coupled with maximum internal and external rotation, respectively. All parameters measured were significantly different between healthy and injured knees (P < 0.05), with exception of lateral plateau without stress. The difference between injured and healthy knees for medial and lateral tibial plateaus anterior displacement (P < 0.05) and rotation (P < 0.001) was statistically significant. It was found a significant correlation between the global rotation of the lateral tibial plateau (lateral plateau with internal + external rotation) with pivot-shift, and between the anterior global translation of both tibial plateaus (medial + lateral tibial plateau) with Lachman. The anterior global translation of both tibial plateaus was the most specific test with a cut-off point of 11.1 mm (93.8 %), and the global rotation of the lateral tibial plateau was the most sensitive test with a correspondent cut-off point of 15.1 mm (92.9 %). Objective laxity quantification of ACL-injured knees showed increased sagittal laxity, and simultaneously in sagittal and transversal planes, when compared to their healthy contralateral knee. Moreover, when measuring instability from anterior cruciate ligament ruptures, the anterior global translation of both tibial plateaus and global rotation of the lateral tibial plateau add diagnostic specificity and sensitivity. This work strengthens the evidence that the anterior cruciate ligament plays an important biomechanical role in controlling the anterior translation, but also both internal and external rotation. The high sensitivity and specificity of this device in objectively identifying and measuring the multiplanar instability clearly guides stability restoration clinical procedures. Level of evidence Cross-sectional study, Level III.
Measurement and interpretation of crustal deformation rates associated with postglacial rebound

NASA Technical Reports Server (NTRS)

Davis, James L.

1994-01-01

Analysis of Global Positioning System (GPS) data from two sites separated by horizontal distance of only approximately 2.2 m yielded phase residuals exhibiting a systematic elevation angle dependence. One of the two GPS antennas was mounted on an approximately 1 m high concrete pillar, and the other was mounted on a standard wooden tripod. We performed elevation angle cutoff tests with these data, and established that the vertical coordinate of site position was sensitive to the minimum elevation angle (elevation cutoff) of the data analyzed. For example, the vertical coordinate of site position changed by 9.7 plus or minus 0.8 mm when the minimum elevation angle was increased from 10 to 25. We performed simulations based on a simple (ray tracing) multipath model with a single horizontal reflector, and demonstrated that the elevation angle cutoff test results and the pattern of the residual versus elevation angle could be qualitatively reproduced if the reflector were located 0.1-0.2 m beneath the antenna phase center. We therefore, hypothesized that the source of the elevation-angle-dependent error were multipath reflections and scattering and that the horizontal surface of the pillar, located a distance of approximately 0.2 m beneath the antenna phase center, was the primary reflector. We tested this hypothesis by placing microwave absorbing material between the antenna and the pillar in a number of configurations and analyzed the changes in apparent position of the antenna. The results indicate that (1) the horizontal surface of the pillar is indeed the main reflector, (2) both the concrete and the metal plate embedded in the pillar are significant reflectors, and (3) the reflection can be reduced to a great degree by the use of microwave absorbing materials. These results have significant implications for the accuracy of global GPS geodetic tracking networks which use pillar-antenna configuration identical or similar to the one used here (at the Westford WFRD GPS site).
A nonlinear estimator for reconstructing the angular velocity of a spacecraft without rate gyros

NASA Technical Reports Server (NTRS)

Polites, M. E.; Lightsey, W. D.

1991-01-01

A scheme for estimating the angular velocity of a spacecraft without rate gyros is presented. It is based upon a nonlinear estimator whose inputs are measured inertial vectors and their calculated time derivatives relative to vehicle axes. It works for all spacecraft attitudes and requires no knowledge of attitude. It can use measurements from a variety of onboard sensors like Sun sensors, star trackers, or magnetometers, and in concert. It can also use look angle measurements from onboard tracking antennas for tracking and data relay satellites or global positioning system satellites. In this paper, it is applied to a Sun point scheme on the Hubble Space Telescope assuming all or most of its onboard rate gyros have failed. Simulation results are presented for verification.
The Effects of Core-Mantle Interactions on Earth Rotation, Surface Deformation, and Gravity Changes

NASA Astrophysics Data System (ADS)

Watkins, A.; Gross, R. S.; Fu, Y.

2017-12-01

The length-of-day (LOD) contains a 6-year signal, the cause of which is currently unknown. The signal remains after removing tidal and surface fluid effects, thus the cause is generally believed to be angular momentum exchange between the mantle and core. Previous work has established a theoretical relationship between pressure variations at the core-mantle boundary (CMB) and resulting deformation of the overlying mantle and crust. This study examines globally distributed GPS deformation data in search of this effect, and inverts the discovered global inter-annual component for the CMB pressure variations. The geostrophic assumption is then used to obtain fluid flow solutions at the edge of the core from the CMB pressure variations. Taylor's constraint is applied to obtain the flow deeper within the core, and the equivalent angular momentum and LOD changes are computed and compared to the known 6-year LOD signal. The amplitude of the modeled and measured LOD changes agree, but the degree of period and phase agreement is dependent upon the method of isolating the desired component in the GPS position data. Implications are discussed, and predictions are calculated for surface gravity field changes that would arise from the CMB pressure variations.
Post-acceleration of laser driven protons with a compact high field linac

NASA Astrophysics Data System (ADS)

Sinigardi, Stefano; Londrillo, Pasquale; Rossi, Francesco; Turchetti, Giorgio; Bolton, Paul R.

2013-05-01

We present a start-to-end 3D numerical simulation of a hybrid scheme for the acceleration of protons. The scheme is based on a first stage laser acceleration, followed by a transport line with a solenoid or a multiplet of quadrupoles, and then a post-acceleration section in a compact linac. Our simulations show that from a laser accelerated proton bunch with energy selection at ~ 30MeV, it is possible to obtain a high quality monochromatic beam of 60MeV with intensity at the threshold of interest for medical use. In the present day experiments using solid targets, the TNSA mechanism describes accelerated bunches with an exponential energy spectrum up to a cut-off value typically below ~ 60MeV and wide angular distribution. At the cut-off energy, the number of protons to be collimated and post-accelerated in a hybrid scheme are still too low. We investigate laser-plasma acceleration to improve the quality and number of the injected protons at ~ 30MeV in order to assure efficient post-acceleration in the hybrid scheme. The results are obtained with 3D PIC simulations using a code where optical acceleration with over-dense targets, transport and post-acceleration in a linac can all be investigated in an integrated framework. The high intensity experiments at Nara are taken as a reference benchmarks for our virtual laboratory. If experimentally confirmed, a hybrid scheme could be the core of a medium sized infrastructure for medical research, capable of producing protons for therapy and x-rays for diagnosis, which complements the development of all optical systems.
Prevalence and causes of hearing impairment in Africa.

PubMed

Mulwafu, W; Kuper, H; Ensink, R J H

2016-02-01

To systematically assess the data on the prevalence and causes of hearing impairment in Africa. Systematic review on the prevalence and causes of hearing loss in Africa. We undertook a literature search of seven electronic databases (EMBASE, PubMed, Medline, Global Health, Web of Knowledge, Academic Search Complete and Africa Wide Information) and manually searched bibliographies of included articles. The search was restricted to population-based studies on hearing impairment in Africa. Data were extracted using a standard protocol. We identified 232 articles and included 28 articles in the final analysis. The most common cut-offs used for hearing impairment were 25 and 30 dB HL, but this ranged between 15 and 40 dB HL. For a cut-off of 25 dB, the median was 7.7% for the children- or school-based studies and 17% for population-based studies. For a cut-off of 30 dB HL, the median was 6.6% for the children or school-based studies and 31% for population-based studies. In schools for the deaf, the most common cause of hearing impairment was cryptogenic deafness (50%) followed by infectious causes (43%). In mainstream schools and general population, the most common cause of hearing impairment was middle ear disease (36%), followed by undetermined causes (35%) and cerumen impaction (24%). There are very few population-based studies available to estimate the prevalence of hearing impairment in Africa. Those studies that are available use different cut-offs, making comparison difficult. However, the evidence suggests that the prevalence of hearing impairment is high and that much of it is avoidable or treatable. © 2015 John Wiley & Sons Ltd.

Extending the ISC-GEM Global Earthquake Instrumental Catalogue

NASA Astrophysics Data System (ADS)

Di Giacomo, Domenico; Engdhal, Bob; Storchak, Dmitry; Villaseñor, Antonio; Harris, James

2015-04-01

After a 27-month project funded by the GEM Foundation (www.globalquakemodel.org), in January 2013 we released the ISC-GEM Global Instrumental Earthquake Catalogue (1900 2009) (www.isc.ac.uk/iscgem/index.php) as a special product to use for seismic hazard studies. The new catalogue was necessary as improved seismic hazard studies necessitate that earthquake catalogues are homogeneous (to the largest extent possible) over time in their fundamental parameters, such as location and magnitude. Due to time and resource limitation, the ISC-GEM catalogue (1900-2009) included earthquakes selected according to the following time-variable cut-off magnitudes: Ms=7.5 for earthquakes occurring before 1918; Ms=6.25 between 1918 and 1963; and Ms=5.5 from 1964 onwards. Because of the importance of having a reliable seismic input for seismic hazard studies, funding from GEM and two commercial companies in the US and UK allowed us to start working on the extension of the ISC-GEM catalogue both for earthquakes that occurred beyond 2009 and for earthquakes listed in the International Seismological Summary (ISS) which fell below the cut-off magnitude of 6.25. This extension is part of a four-year program that aims at including in the ISC-GEM catalogue large global earthquakes that occurred before the beginning of the ISC Bulletin in 1964. In this contribution we present the updated ISC GEM catalogue, which will include over 1000 more earthquakes that occurred in 2010 2011 and several hundreds more between 1950 and 1959. The catalogue extension between 1935 and 1949 is currently underway. The extension of the ISC-GEM catalogue will also be helpful for regional cross border seismic hazard studies as the ISC-GEM catalogue should be used as basis for cross-checking the consistency in location and magnitude of those earthquakes listed both in the ISC GEM global catalogue and regional catalogues.
Development of a long wave infrared detector for SGLI instrument

NASA Astrophysics Data System (ADS)

Dariel, Aurélien; Chorier, P.; Reeb, N.; Terrier, B.; Vuillermet, M.; Tribolet, P.

2007-10-01

The Japanese Aerospace Exploration Agency (JAXA) will be conducting the Global Change Observation Mission (GCOM) for monitoring of global environmental change. SGLI (Second Generation Global Imager) is an optical sensor on board GCOM-C (Climate), that includes a Long Wave IR Detector (LWIRD) sensitive up to about 13 μm. SGLI will provide high accuracy measurements of the atmosphere (aerosol, cloud ...), the cryosphere (glaciers, snow, sea ice ...), the biomass and the Earth temperature (sea and land). Sofradir is a major supplier of Space industry based on the use of a Space qualified MCT technology for detectors from 0.8 to 15 μm. This mature and reproducible technology has been used for 15 years to produce thousands of LWIR detectors with cut-off wavelengths between 9 and 12 μm. NEC Toshiba Space, prime contractor for the Second Generation Global Imager (SGLI), has selected SOFRADIR for its heritage in space projects and Mercury Cadmium Telluride (MCT) detectors to develop the LWIR detector. This detector includes two detection circuits for detection at 10.8 μm and 12.0 μm, hybridized on a single CMOS readout circuit. Each detection circuit is made of 20x2 square pixels of 140 μm. In order to optimize the overall performance, each pixel is made of 5x5 square sub-pixels of 28 μm and the readout circuit enables sub-pixel deselection. The MCT material and the photovoltaic technology are adapted to maximize response for the requested bandwidths: cut-off wavelengths of the 2 detection circuits are 12.6 and 13.4 μm at 55K. This detector is packaged into a sealed housing for full integration into a Dewar at 55K. This paper describes the main technical requirements, the design features of this detector, including trade-offs regarding performance optimization, and presents preliminary electro-optical results.
Applicability of a novel immunoassay based on surface plasmon resonance for the diagnosis of Chagas disease.

PubMed

Luz, João G G; Souto, Dênio E P; Machado-Assis, Girley F; de Lana, Marta; Luz, Rita C S; Martins-Filho, Olindo A; Damos, Flávio S; Martins, Helen R

2016-02-15

We defined the methodological criteria for the interpretation of the results provided by a novel immunoassay based on surface plasmon resonance (SPR) to detect antibodies anti-Trypanosoma cruzi in human sera (SPRCruzi). Then, we evaluated its applicability as a diagnostic tool for Chagas disease. To define the cut-off point and serum dilution factor, 57 samples were analyzed at SPRCruzi and the obtained values of SPR angle displacement (ΔθSPR) were submitted to statistical analysis. Adopting the indicated criteria, its performance was evaluated into a wide panel of samples, being 99 Chagas disease patients, 30 non-infected subjects and 42 with other parasitic/infectious diseases. In parallel, these samples were also analyzed by ELISA. Our data demonstrated that 1:320 dilution and cut-off point at ∆θSPR=17.2 m° provided the best results. Global performance analysis demonstrated satisfactory sensitivity (100%), specificity (97.2%), positive predictive value (98%), negative predictive value (100%) and global accuracy (99.6%). ELISA and SPRCruzi showed almost perfect agreement, mainly between chagasic and non-infected individuals. However, the new immunoassay was better in discriminate Chagas disease from other diseases. This work demonstrated the applicability of SPRCruzi as a feasible, real time, label free, sensible and specific methodology for the diagnosis of Chagas disease. Copyright © 2015 Elsevier B.V. All rights reserved.
Slump sitting X-ray of the lumbar spine is superior to the conventional flexion view in assessing lumbar spine instability.

PubMed

Hey, Hwee Weng Dennis; Lau, Eugene Tze-Chun; Lim, Joel-Louis; Choong, Denise Ai-Wen; Tan, Chuen-Seng; Liu, Gabriel Ka-Po; Wong, Hee-Kit

2017-03-01

Flexion radiographs have been used to identify cases of spinal instability. However, current methods are not standardized and are not sufficiently sensitive or specific to identify instability. This study aimed to introduce a new slump sitting method for performing lumbar spine flexion radiographs and comparison of the angular range of motions (ROMs) and displacements between the conventional method and this new method. This study used is a prospective study on radiological evaluation of the lumbar spine flexion ROMs and displacements using dynamic radiographs. Sixty patients were recruited from a single spine tertiary center. Angular and displacement measurements of lumbar spine flexion were carried out. Participants were randomly allocated into two groups: those who did the new method first, followed by the conventional method versus those who did the conventional method first, followed by the new method. A comparison of the angular and displacement measurements of lumbar spine flexion between the conventional method and the new method was performed and tested for superiority and non-inferiority. The measurements of global lumbar angular ROM were, on average, 17.3° larger (p<.0001) using the new slump sitting method compared with the conventional method. They were most significant at the levels of L3-L4, L4-L5, and L5-S1 (p<.0001, p<.0001 and p=.001, respectively). There was no significant difference between both methods when measuring lumbar displacements (p=.814). The new method of slump sitting dynamic radiograph was shown to be superior to the conventional method in measuring the angular ROM and non-inferior to the conventional method in the measurement of displacement. Copyright © 2016 Elsevier Inc. All rights reserved.
Plate Motion and Crustal Deformation Estimated with Geodetic Data from the Global Positioning System

NASA Technical Reports Server (NTRS)

Argus, Donald F.; Heflin, Michael B.

1995-01-01

We use geodetic data taken over four years with the Global Positioning System (GPS) to estimate: (1) motion between six major plates and (2) motion relative to these plates of ten sites in plate boundary zones. The degree of consistency between geodetic velocities and rigid plates requires the (one-dimensional) standard errors in horizontal velocities to be approx. 2 mm/yr. Each of the 15 angular velocities describing motion between plate pairs that we estimate with GPS differs insignificantly from the corresponding angular velocity in global plate motion model NUVEL-1A, which averages motion over the past 3 m.y. The motion of the Pacific plate relative to both the Eurasian and North American plates is observed to be faster than predicted by NUVEL-1A, supporting the inference from Very Long B ase- line Interferometry (VLBI) that motion of the Pacific plate has speed up over the past few m.y. The Eurasia-North America pole of rotation is estimated to be north of NUVEL-1A, consistent with the independent hypothesis that the pole has recently migrated northward across northeast Asia to near the Lena River delta. Victoria, which lies above the main thrust at the Cascadia subduction zone, moves relative to the interior of the overriding plate at 30% of the velocity of the subducting plate, reinforcing the conclusion that the thrust there is locked beneath the continental shelf and slope.
Global and Regional Axial Ocean Angular Momentum Signals and Length-of-day Variations (1985-1996)

NASA Technical Reports Server (NTRS)

Ponte, Rui M.; Stammer, Detlef

2000-01-01

Changes in ocean angular momentum M about the polar axis are related to fluctuations in zonal currents (relative component M(sub tau) and latitudinal shifts in mass (planetary component M(sub Omega). Output from a 1 deg. ocean model is used to calculate global M(sub tau), (sub Omega), and M time series at 5 day intervals for the period January 1985 to April 1996. The annual cycle in M(sub tau), M(sub Omega), and M is larger than the semiannual cycle, and M(sub Omega) amplitudes are nearly twice those of M(sub tau). Year-to-year modulation of the seasonal cycle is present, but interannual variability is weak. The spectrum of M is red (background slope between omega(sup -1) and omega(sup -2) at sub-seasonal periods, implying a white or blue spectrum for the external torque on the ocean. Comparisons with previous studies indicate the importance of direct atmospheric forcing in inducing sub-seasonal M signals, relative to instabilities and other internal sources of rapid oceanic signals. Regional angular momentum estimates show that seasonal variability tends to be larger at low latitudes, but many local maxima exist because of the spatial structure of zonal current and mass variability. At seasonal timescales, latitudes approx. 20 deg. S - 10 deg. N contribute substantial variability to M(sub Omega), while signals in M(sub tau) can be traced to Antarctic Circumpolar Current transports and associated circulation. Variability in M is found to be small when compared with similar time series for the atmosphere and the solid Earth, but ocean signals are significantly coherent with atmosphere-solid Earth residuals, implying a measurable oceanic impact on length-of-day variations.
Global and Regional Axial Ocean Angular Momentum Signals and Length-of-Day Variations (1985-1996)

NASA Technical Reports Server (NTRS)

Ponte, Rui M.; Stammer, Detlef

1999-01-01

Changes in ocean angular momentum about the polar axis (M) are related to fluctuations in zonal currents (relative component M(sub r)) and latitudinal shifts in mass (planetary component M(sub Omega)). Output from a 1 deg ocean model is used to calculate global M(sub r), M(sub Omega), and M time series at 5-day intervals for the period January 1985-April 1996. The annual cycle in M(sub r), M(sub Omega), and M is larger than the semiannual cycle, and M(sub Omega) amplitudes are nearly twice those of M(sub r). Year-to-year modulation of the seasonal cycle is present, but interannual variability is weak. The spectrum of M is red (background slope between omega(sup (-1) and omega(sup -2)) at subseasonal periods, implying a white or blue spectrum for the external torque on the ocean. Comparisons with previous studies indicate the importance of direct atmospheric forcing in inducing subseasonal M signals, relative to instabilities and other internal sources of rapid oceanic signals. Regional angular momentum estimates show that seasonal variability tends to be larger at low latitudes but there are many local maxima due to the spatial structure of zonal current and mass variability. At seasonal timescales, latitudes approximately 20 S - 10 N contribute substantial variability to M(sub Omega), while signals in M(sub r) can be traced to Antarctic Circumpolar Current transports and associated circulation. Variability in M is found to be small when compared with similar time series for the atmosphere and the solid Earth, but ocean signals are significantly coherent with atmosphere-solid Earth residuals, implying a measurable oceanic impact on length-of-day variations.
Quantitative Pointwise Estimate of the Solution of the Linearized Boltzmann Equation

NASA Astrophysics Data System (ADS)

Lin, Yu-Chu; Wang, Haitao; Wu, Kung-Chien

2018-04-01

We study the quantitative pointwise behavior of the solutions of the linearized Boltzmann equation for hard potentials, Maxwellian molecules and soft potentials, with Grad's angular cutoff assumption. More precisely, for solutions inside the finite Mach number region (time like region), we obtain the pointwise fluid structure for hard potentials and Maxwellian molecules, and optimal time decay in the fluid part and sub-exponential time decay in the non-fluid part for soft potentials. For solutions outside the finite Mach number region (space like region), we obtain sub-exponential decay in the space variable. The singular wave estimate, regularization estimate and refined weighted energy estimate play important roles in this paper. Our results extend the classical results of Liu and Yu (Commun Pure Appl Math 57:1543-1608, 2004), (Bull Inst Math Acad Sin 1:1-78, 2006), (Bull Inst Math Acad Sin 6:151-243, 2011) and Lee et al. (Commun Math Phys 269:17-37, 2007) to hard and soft potentials by imposing suitable exponential velocity weight on the initial condition.
Absolute Effective Area of the Chandra High-Resolution Mirror Assembly

NASA Technical Reports Server (NTRS)

Schwartz, D. A.; David, L. P.; Donnelly, R. H.; Edgar, R. J.; Gaetz, T. J.; Jerius, D.; Juda, M.; Kellogg, E. M.; McNamara, B. R.; Dewey, D.

2000-01-01

The Chandra X-ray Observatory was launched in July 1999, and is returning exquisite sub-arcsecond x-ray images of star groups, supernova remnants, galaxies, quasars, and clusters of galaxies. In addition to being the premier X-ray observatory in terms of angular and spectral resolution, Chandra is the best calibrated X-ray facility ever flown. We discuss here the calibration of the effective area of the High Resolution Mirror Assembly. Because we do not know the absolute X-ray flux density of any celestial source, this must be based primarily on ground measurements and on modeling. In particular, we must remove the calibrated modeled responses of the detectors and gratings to obtain the mirror area. For celestial sources which may be assumed to have smoothly varying spectra, such as the Crab Nebula, we may verify the continuity of the area calibration as a function of energy. This is of significance in energy regions such as the Ir M-edges, or near the critical grazing angle cutoff of the various mirror shells.
Quantitative Pointwise Estimate of the Solution of the Linearized Boltzmann Equation

NASA Astrophysics Data System (ADS)

Lin, Yu-Chu; Wang, Haitao; Wu, Kung-Chien

2018-06-01

We study the quantitative pointwise behavior of the solutions of the linearized Boltzmann equation for hard potentials, Maxwellian molecules and soft potentials, with Grad's angular cutoff assumption. More precisely, for solutions inside the finite Mach number region (time like region), we obtain the pointwise fluid structure for hard potentials and Maxwellian molecules, and optimal time decay in the fluid part and sub-exponential time decay in the non-fluid part for soft potentials. For solutions outside the finite Mach number region (space like region), we obtain sub-exponential decay in the space variable. The singular wave estimate, regularization estimate and refined weighted energy estimate play important roles in this paper. Our results extend the classical results of Liu and Yu (Commun Pure Appl Math 57:1543-1608, 2004), (Bull Inst Math Acad Sin 1:1-78, 2006), (Bull Inst Math Acad Sin 6:151-243, 2011) and Lee et al. (Commun Math Phys 269:17-37, 2007) to hard and soft potentials by imposing suitable exponential velocity weight on the initial condition.
Modeling of projection electron lithography

NASA Astrophysics Data System (ADS)

Mack, Chris A.

2000-07-01

Projection Electron Lithography (PEL) has recently become a leading candidate for the next generation of lithography systems after the successful demonstration of SCAPEL by Lucent Technologies and PREVAIL by IBM. These systems use a scattering membrane mask followed by a lens with limited angular acceptance range to form an image of the mask when illuminated by high energy electrons. This paper presents an initial modeling system for such types of projection electron lithography systems. Monte Carlo modeling of electron scattering within the mask structure creates an effective mask 'diffraction' pattern, to borrow the standard optical terminology. A cutoff of this scattered pattern by the imaging 'lens' provides an electron energy distribution striking the wafer. This distribution is then convolved with a 'point spread function,' the results of a Monte Carlo scattering calculation of a point beam of electrons striking the resist coated substrate and including the effects of beam blur. Resist exposure and development models from standard electron beam lithography simulation are used to simulate the final three-dimensional resist profile.
A new high quality X-ray source for Cultural Heritage

NASA Astrophysics Data System (ADS)

Walter, Philippe; Variola, Alessandro; Zomer, Fabian; Jaquet, Marie; Loulergue, Alexandre

2009-09-01

Compton based photon sources have generated much interest since the rapid advance in laser and accelerator technologies has allowed envisaging their utilisation for ultra-compact radiation sources. These should provide X-ray short pulses with a relatively high average flux. Moreover, the univocal dependence between the scattered photon energy and its angle gives the possibility of obtaining a quasi-monochromatic beam with a simple diaphragm system. For the most ambitious projects the expected performance takes into account a rate of 10-10 photons/s, with an angular divergence of few mrad, an X-ray energy cut-off of few tens of keV and a bandwidth ΔE/E˜1-10%. Even if the integrated rate cannot compete with synchrotron radiation sources, the cost and the compactness of these Compton based machines make them attractive for a wide spectrum of applications. We explore here the interest of these systems for Cultural Heritage preservation. To cite this article: P. Walter et al., C. R. Physique 10 (2009).
Diagnostic performance of body mass index using the Western Pacific Regional Office of World Health Organization reference standards for body fat percentage.

PubMed

Yoon, Jong Lull; Cho, Jung Jin; Park, Kyung Mi; Noh, Hye Mi; Park, Yong Soon

2015-02-01

Associations between body mass index (BMI), body fat percentage (BF%), and health risks differ between Asian and European populations. BMI is commonly used to diagnose obesity; however, its accuracy in detecting adiposity in Koreans is unknown. The present cross-sectional study aimed at assessing the accuracy of BMI in determining BF%-defined obesity in 6,017 subjects (age 20-69 yr, 43.6% men) from the 2009 Korean National Health and Nutrition Examination Survey. We assessed the diagnostic performance of BMI using the Western Pacific Regional Office of World Health Organization reference standard for BF%-defined obesity by sex and age and identified the optimal BMI cut-off for BF%-defined obesity using receiver operating characteristic curve analysis. BMI-defined obesity (≥25 kg/m(2)) was observed in 38.7% of men and 28.1% of women, with a high specificity (89%, men; 84%, women) but poor sensitivity (56%, men; 72% women) for BF%-defined obesity (25.2%, men; 31.1%, women). The optimal BMI cut-off (24.2 kg/m(2)) had 78% sensitivity and 71% specificity. BMI demonstrated limited diagnostic accuracy for adiposity in Korea. There was a -1.3 kg/m(2) difference in optimal BMI cut-offs between Korea and America, smaller than the 5-unit difference between the Western Pacific Regional Office and global World Health Organization obesity criteria.
Analysis and Experimentation of Control Strategies for Underactuated Spacecraft

DTIC Science & Technology

2009-09-01

control techniques that provide time -invariant global asymptotic stability of the fully actuated spacecraft system of equations. Although these control ...momentum wheel actuators in finite time under the restriction that the total angular momentum vector of the system is zero. This control methodology...can be stabilizable to an arbitrarily small region about the equilibrium of the system via time -invariant smooth state feedback control
Transverse-momentum-dependent quark distribution functions of spin-one targets: Formalism and covariant calculations

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

Ninomiya, Yu; Bentz, Wolfgang; Cloet, Ian C.

In this paper, we present a covariant formulation and model calculations of the leading-twist time-reversal even transverse-momentum-dependent quark distribution functions (TMDs) for a spin-one target. Emphasis is placed on a description of these three-dimensional distribution functions which is independent of any constraints on the spin quantization axis. We apply our covariant spin description to all nine leading-twist time-reversal even ρ meson TMDs in the framework provided by the Nambu–Jona-Lasinio model, incorporating important aspects of quark confinement via the infrared cutoff in the proper-time regularization scheme. In particular, the behaviors of the three-dimensional TMDs in a tensor polarized spin-one hadron aremore » illustrated. Sum rules and positivity constraints are discussed in detail. Our results do not exhibit the familiar Gaussian behavior in the transverse momentum, and other results of interest include the finding that the tensor polarized TMDs—associated with spin-one hadrons—are very sensitive to quark orbital angular momentum, and that the TMDs associated with the quark operator γ +γ Tγ 5 would vanish were it not for dynamical chiral symmetry breaking. In addition, we find that 44% of the ρ meson's spin is carried by the orbital angular momentum of the quarks, and that the magnitude of the tensor polarized quark distribution function is about 30% of the unpolarized quark distribution. Finally, a qualitative comparison between our results for the tensor structure of a quark-antiquark bound state is made to existing experimental and theoretical results for the two-nucleon (deuteron) bound state.« less
Transverse-momentum-dependent quark distribution functions of spin-one targets: Formalism and covariant calculations

DOE PAGES

Ninomiya, Yu; Bentz, Wolfgang; Cloet, Ian C.

2017-10-24

In this paper, we present a covariant formulation and model calculations of the leading-twist time-reversal even transverse-momentum-dependent quark distribution functions (TMDs) for a spin-one target. Emphasis is placed on a description of these three-dimensional distribution functions which is independent of any constraints on the spin quantization axis. We apply our covariant spin description to all nine leading-twist time-reversal even ρ meson TMDs in the framework provided by the Nambu–Jona-Lasinio model, incorporating important aspects of quark confinement via the infrared cutoff in the proper-time regularization scheme. In particular, the behaviors of the three-dimensional TMDs in a tensor polarized spin-one hadron aremore » illustrated. Sum rules and positivity constraints are discussed in detail. Our results do not exhibit the familiar Gaussian behavior in the transverse momentum, and other results of interest include the finding that the tensor polarized TMDs—associated with spin-one hadrons—are very sensitive to quark orbital angular momentum, and that the TMDs associated with the quark operator γ +γ Tγ 5 would vanish were it not for dynamical chiral symmetry breaking. In addition, we find that 44% of the ρ meson's spin is carried by the orbital angular momentum of the quarks, and that the magnitude of the tensor polarized quark distribution function is about 30% of the unpolarized quark distribution. Finally, a qualitative comparison between our results for the tensor structure of a quark-antiquark bound state is made to existing experimental and theoretical results for the two-nucleon (deuteron) bound state.« less
Angular correlation between IceCube high-energy starting events and starburst sources

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

Moharana, Reetanjali; Razzaque, Soebur, E-mail: moharana.reetanjali@mail.huji.ac.il, E-mail: srazzaque@uj.ac.za

Starburst galaxies and star-forming regions in the Milkyway, with high rate of supernova activities, are candidate sources of high-energy neutrinos. Using a gamma-ray selected sample of these sources we perform statistical analysis of their angular correlation with the four-year sample of high-energy starting events (HESE), detected by the IceCube Neutrino Observatory. We find that the two samples (starburst galaxies and local star-forming regions) are correlated with cosmic neutrinos at ∼ (2–3)σ (pre-trial) significance level, when the full HESE sample with deposited energy ∼> 20 TeV is considered. However when we consider the HESE sample with deposited energy ∼> 60 TeV,more » which is almost free of atmospheric neutrino and muon backgrounds, the significance of correlation decreased drastically. We perform a similar study for Galactic sources in the 2nd Catalog of Hard Fermi -LAT Sources (2FHL, >50 GeV) catalog as well, obtaining ∼ (2–3)σ (pre-trial) correlation, however the significance of correlation increases with higher cutoff energy in the HESE sample for this case. We also fit available gamma-ray data from these sources using a pp interaction model and calculate expected neutrino fluxes. We find that the expected neutrino fluxes for most of the sources are at least an order of magnitude lower than the fluxes required to produce the HESE neutrinos from these sources. This puts the starburst sources being the origin of the IceCube HESE neutrinos in question.« less
Reflectivity Spectra for Commonly Used Reflectors

NASA Astrophysics Data System (ADS)

Janecek, Martin

2012-06-01

Monte Carlo simulations play an important role in developing and evaluating the performance of radiation detection systems. To accurately model a reflector in an optical Monte Carlo simulation, the reflector's spectral response has to be known. We have measured the reflection coefficient for many commonly used reflectors for wavelengths from 250 nm to 800 nm. The reflectors were also screened for fluorescence and angular distribution changes with wavelength. The reflectors examined in this work include several polytetrafluoroethylene (PTFE) reflectors, Spectralon, GORE diffuse reflector, titanium dioxide paint, magnesium oxide, nitrocellulose filter paper, Tyvek paper, Lumirror, Melinex, ESR films, and aluminum foil. All PTFE films exhibited decreasing reflectivity with longer wavelengths due to transmission. To achieve >;0.95 reflectivity in the 380 to 500 nm range, the PTFE films have to be at least 0.5 mm thick-nitrocellulose is a good alternative if a thin diffuse reflector is needed. Several of the reflectors have sharp declines in reflectivity below a cut-off wavelength, including TiO2 (420 nm), ESR film (395 nm), nitrocellulose (330 nm), Lumirror (325 nm), and Melinex (325 nm). PTFE-like reflectors were the only examined reflectors that had reflectivity above 0.90 for wavelengths below 300 nm. Lumirror, Melinex, and ESR film exhibited fluorescence. Lumirror and Melinex are excited by wavelengths between 320 and 420 nm and have their emission peaks located at 440 nm, while ESR film is excited by wavelengths below 400 nm and the emission peak is located at 430 nm. Lumirror and Melinex also exhibited changing angular distributions with wavelength.
Positioning stability improvement with inter-system biases on multi-GNSS PPP

NASA Astrophysics Data System (ADS)

Choi, Byung-Kyu; Yoon, Hasu

2018-07-01

The availability of multiple signals from different Global Navigation Satellite System (GNSS) constellations provides opportunities for improving positioning accuracy and initial convergence time. With dual-frequency observations from the four constellations (GPS, GLONASS, Galileo, and BeiDou), it is possible to investigate combined GNSS precise point positioning (PPP) accuracy and stability. The differences between GNSS systems result in inter-system biases (ISBs). We consider several ISB values such as GPS-GLONASS, GPS-Galileo, and GPS-BeiDou. These biases are compliant with key parameters defined in the multi-GNSS PPP processing. In this study, we present a unified PPP method that sets ISB values as fixed or constant. A comprehensive analysis that includes satellite visibility, position dilution of precision, position accuracy is performed to evaluate a unified PPP method with constrained cut-off elevation angles. Compared to the conventional PPP solutions, our approach shows more stable positioning at a constrained cut-off elevation angle of 50 degrees.
ESA DUE GlobTemperature project: Infrared-based LST Product

NASA Astrophysics Data System (ADS)

Ermida, Sofia; Pires, Ana; Ghent, Darren; Trigo, Isabel; DaCamara, Carlos; Remedios, John

2016-04-01

One of the purposes of the GlobTemperature project is to provide a product of global Land Surface Temperature (LST) based on Geostationary Earth Orbit (GEO) and Low Earth polar Orbit (LEO) satellite data. The objective is to use existing LST products, which are obtained from different sensors/platforms, combining them into a harmonized product for a reference view angle. In a first approach, only infra-red based retrievals are considered, and LEO LSTs will be used as a common denominator among geostationary sensors. LST data is provided by a wide range of sensors to optimize spatial coverage, namely: (i) 2 LEO sensors - the Advanced Along Track Scanning Radiometer (AATSR) series of instruments on-board ESA's Envisat, and the Moderate Resolution Imaging Spectroradiometer (MODIS) on-board NASA's TERRA and AQUA; and (ii) 3 GEO sensors - the Spinning Enhanced Visible and Infrared Imager (SEVIRI) on-board EUMETSAT's Meteosat Second Generation (MSG), the Japanese Meteorological Imager (JAMI) on-board the Japanese Meteorological Association (JMA) Multifunction Transport SATellite (MTSAT-2), and NASA's Geostationary Operational Environmental Satellites (GOES). The merged LST product is generated in two steps: 1) calibration between each LEO and each GEO that consists in the removal of systematic differences (associated to sensor type and LST algorithms, including calibration, atmospheric and surface emissivity corrections, amongst others) represented by linear regressions; 2) angular correction that consists in bringing all LST data to reference (nadir) view. Angular effects on LST are estimated by means of a kernel model of the surface thermal emission, which describes the angular dependence of LST as function of viewing and illumination geometry. The model is adjusted to MODIS and SEVIRI/MSG LST estimates and validated against LST retrievals from those sensors obtained for other years (not used in the calibration). It is shown that the model leads to a reduction of LST differences between the two sensors, indicating that it may be used to effectively estimate/correct angular dependence in LST. A global set of kernel model parameters is finally obtained by adjusting the model to either a GEO and a LEO or the two LEOs (poles). A first version of the merged product will be released in 2016, available for download through the GlobTemperature portal. This includes only the calibration process (step 1), incorporating LST data from SEVIRI, GOES, MTSAT and MODIS; information on directional effects added as an extra layer of information. A second version of the dataset with a better incorporation of the angular correction is currently in preparation.

Antiproton-proton annihilation into light neutral meson pairs within an effective meson theory

NASA Astrophysics Data System (ADS)

Wang, Ying; Bystritskiy, Yury M.; Ahmadov, Azad I.; Tomasi-Gustafsson, Egle

2017-08-01

Antiproton-proton annihilation into light neutral mesons in the few GeV energy domain is investigated in view of a global description of the existing data and predictions for future work at the Antiproton Annihilation at Darmstadt (PANDA) experiment at the Facility for Antiproton and Ion Research (FAIR). An effective meson model earlier developed, with mesonic and baryonic degrees of freedom in s , t , and u channels, is applied here to π0π0 production. Form factors with logarithmic s and t (u ) dependencies are applied. A fair agreement with the existing angular distributions is obtained. Applying SU(3) symmetry, it is straightforward to recover the angular distributions for π0η and η η production in the same energy range. A good agreement is generally obtained with all existing data.
Comparison of the hydrological excitation functions HAM of polar motion for the period 1980.0-2007.0

NASA Astrophysics Data System (ADS)

Nastula, J.; Pasnicka, M.; Kolaczek, B.

2011-10-01

In this study we compared contributions of polar motion excitation determined from hydrological models and harmonic coefficients of the Earth gravity field obtained from Gravity Recovery and Climate Experiment (GRACE). Hydrological excitation function (hydrological angular momentum - HAM) has been estimated from models of global hydrology, based on the observed distribution of surface water, snow, ice and soil moisture. All of them were compared with observed Geodetic Angular Momentum (GAM), excitations of polar motion. The spectra of these excitation functions of polar motion and residual geodetic excitation function G-A-O obtained from GAM by elimination of atmospheric and oceanic excitation functions were computed too. Phasor diagrams of the seasonal components of the polar motion excitation functions of all HAM excitation functions as well as of two GRACE solutions: CSR, CNES were determined and discussed.
The latitude-height structure of 40-50 day variations in atmospheric angular momentum

NASA Technical Reports Server (NTRS)

Anderson, J. R.; Rosen, R. D.

1983-01-01

Using five years of U.S. National Meteorological Center twice-daily global analyses, a description of the two-dimensional latitude-height structure of the winds responsible for quasi-periodic variations in the relative angular momentum of the atmosphere observed by Langley et al. (1981) is constructed. Cross-spectral and amplitude phase eigenvector techniques indicate that these variations are associated with wave-like motions in the tropical upper troposphere which propagate poleward and downward in phase within the tropics. The tropical component is suggested to be the zonally averaged part of the motions described by Madden and Julian (1971, 1972), while a Northern Hemisphere midlatitude component whose phase is essentially independent of height may be a direct response to the tropical motions. Alternatively, both motions may be the common response to an as yet unidentified tropical forcing.
Vector Observation-Aided/Attitude-Rate Estimation Using Global Positioning System Signals

NASA Technical Reports Server (NTRS)

Oshman, Yaakov; Markley, F. Landis

1997-01-01

A sequential filtering algorithm is presented for attitude and attitude-rate estimation from Global Positioning System (GPS) differential carrier phase measurements. A third-order, minimal-parameter method for solving the attitude matrix kinematic equation is used to parameterize the filter's state, which renders the resulting estimator computationally efficient. Borrowing from tracking theory concepts, the angular acceleration is modeled as an exponentially autocorrelated stochastic process, thus avoiding the use of the uncertain spacecraft dynamic model. The new formulation facilitates the use of aiding vector observations in a unified filtering algorithm, which can enhance the method's robustness and accuracy. Numerical examples are used to demonstrate the performance of the method.
Improved treatment of global positioning system force parameters in precise orbit determination applications

NASA Technical Reports Server (NTRS)

Vigue, Y.; Lichten, S. M.; Muellerschoen, R. J.; Blewitt, G.; Heflin, M. B.

1993-01-01

Data collected from a worldwide 1992 experiment were processed at JPL to determine precise orbits for the satellites of the Global Positioning System (GPS). A filtering technique was tested to improve modeling of solar-radiation pressure force parameters for GPS satellites. The new approach improves orbit quality for eclipsing satellites by a factor of two, with typical results in the 25- to 50-cm range. The resultant GPS-based estimates for geocentric coordinates of the tracking sites, which include the three DSN sites, are accurate to 2 to 8 cm, roughly equivalent to 3 to 10 nrad of angular measure.
Constraints on spin-dependent parton distributions at large x from global QCD analysis

DOE PAGES

Jimenez-Delgado, P.; Avakian, H.; Melnitchouk, W.

2014-09-28

This study investigate the behavior of spin-dependent parton distribution functions (PDFs) at large parton momentum fractions x in the context of global QCD analysis. We explore the constraints from existing deep-inelastic scattering data, and from theoretical expectations for the leading x → 1 behavior based on hard gluon exchange in perturbative QCD. Systematic uncertainties from the dependence of the PDFs on the choice of parametrization are studied by considering functional forms motivated by orbital angular momentum arguments. Finally, we quantify the reduction in the PDF uncertainties that may be expected from future high-x data from Jefferson Lab at 12 GeV.
Quantum tomography for collider physics: illustrations with lepton-pair production

NASA Astrophysics Data System (ADS)

Martens, John C.; Ralston, John P.; Takaki, J. D. Tapia

2018-01-01

Quantum tomography is a method to experimentally extract all that is observable about a quantum mechanical system. We introduce quantum tomography to collider physics with the illustration of the angular distribution of lepton pairs. The tomographic method bypasses much of the field-theoretic formalism to concentrate on what can be observed with experimental data. We provide a practical, experimentally driven guide to model-independent analysis using density matrices at every step. Comparison with traditional methods of analyzing angular correlations of inclusive reactions finds many advantages in the tomographic method, which include manifest Lorentz covariance, direct incorporation of positivity constraints, exhaustively complete polarization information, and new invariants free from frame conventions. For example, experimental data can determine the entanglement entropy of the production process. We give reproducible numerical examples and provide a supplemental standalone computer code that implements the procedure. We also highlight a property of complex positivity that guarantees in a least-squares type fit that a local minimum of a χ 2 statistic will be a global minimum: There are no isolated local minima. This property with an automated implementation of positivity promises to mitigate issues relating to multiple minima and convention dependence that have been problematic in previous work on angular distributions.
Measurements and Modelling of Sputtering Rates with Low Energy Ions

NASA Astrophysics Data System (ADS)

Ruzic, David N.; Smith, Preston C.; Turkot, Robert B., Jr.

1996-10-01

The angular-resolved sputtering yield of Be by D+, and Al by Ar+ was predicted and then measured. A 50 to 1000 eV ion beam from a Colutron was focused on to commercial grade and magnetron target grade samples. The S-65 C grade beryllium samples were supplied by Brush Wellman and the Al samples from TOSOH SMD. In our vacuum chamber the samples can be exposed to a dc D or Ar plasma to remove oxide, load the surface and more-nearly simulate steady state operating conditions in the plasma device. The angular distribution of the sputtered atoms was measured by collection on a single crystal graphite witness plate. The areal density of Be or Al (and BeO2 or Al2O3, after exposure to air) was then measured using a Scanning Auger Spectrometer. Total yield was also measured by deposition onto a quartz crystal oscillator simultaneously to deposition onto the witness plate. A three dimensional version of vectorized fractal TRIM (VFTRIM3D), a Monte-Carlo computer code which includes surface roughness characterized by fractal geometry, was used to predict the angular distribution of the sputtered particles and a global sputtering coefficient. Over a million trajectories were simulated for each incident angle to determine the azimuthal and polar angle distributions of the sputtered atoms. The experimental results match closely with the simulations for total yield, while the measured angular distributions depart somewhat from the predicted cosine curve.
Heat transport in Rayleigh–Bénard convection and angular momentum transport in Taylor–Couette flow: a comparative study

PubMed Central

Brauckmann, Hannes J.

2017-01-01

Rayleigh–Bénard convection and Taylor–Couette flow are two canonical flows that have many properties in common. We here compare the two flows in detail for parameter values where the Nusselt numbers, i.e. the thermal transport and the angular momentum transport normalized by the corresponding laminar values, coincide. We study turbulent Rayleigh–Bénard convection in air at Rayleigh number Ra=107 and Taylor–Couette flow at shear Reynolds number ReS=2×104 for two different mean rotation rates but the same Nusselt numbers. For individual pairwise related fields and convective currents, we compare the probability density functions normalized by the corresponding root mean square values and taken at different distances from the wall. We find one rotation number for which there is very good agreement between the mean profiles of the two corresponding quantities temperature and angular momentum. Similarly, there is good agreement between the fluctuations in temperature and velocity components. For the heat and angular momentum currents, there are differences in the fluctuations outside the boundary layers that increase with overall rotation and can be related to differences in the flow structures in the boundary layer and in the bulk. The study extends the similarities between the two flows from global quantities to local quantities and reveals the effects of rotation on the transport. This article is part of the themed issue ‘Toward the development of high-fidelity models of wall turbulence at large Reynolds number’. PMID:28167575
An Analytical Model for the Prediction of a Micro-Dosimeter Response Function

NASA Technical Reports Server (NTRS)

Badavi, Francis F.; Xapsos, Mike

2008-01-01

A rapid analytical procedure for the prediction of a micro-dosimeter response function in low Earth orbit (LEO), correlated with the Space Transportation System (STS, shuttle) Tissue Equivalent Proportional Counter (TEPC) measurements is presented. The analytical model takes into consideration the energy loss straggling and chord length distribution of the detector, and is capable of predicting energy deposition fluctuations in a cylindrical micro-volume of arbitrary aspect ratio (height/diameter) by incoming ions through both direct and indirect (ray) events. At any designated (ray traced) target point within the vehicle, the model accepts the differential flux spectrum of Galactic Cosmic Rays (GCR) and/or trapped protons at LEO as input. On a desktop PC, the response function of TEPC for each ion in the GCR/trapped field is computed at the average rate of 30 seconds/ion. The ionizing radiation environment at LEO is represented by O'Neill fs GCR model (2004), covering charged particles in the 1 less than or equal to Z less than or equal to 28. O'Neill's free space GCR model is coupled with the Langley Research Center (LaRC) angular dependent geomagnetic cutoff model to compute the transmission coefficient in LEO. The trapped proton environment is represented by a LaRC developed time dependent procedure which couples the AP8MIN/AP8MAX, Deep River Neutron Monitor (DRNM) and F10.7 solar radio frequency measurements. The albedo neutron environment is represented by the extrapolation of the Atmospheric Ionizing Radiation (AIR) measurements. The charged particle transport calculations correlated with STS 51 and 114 flights are accomplished by using the most recent version (2005) of the LaRC deterministic High charge (Z) and Energy TRaNsport (HZETRN) code. We present the correlations between the TEPC model predictions (response function) and TEPC measured differential/integral spectra in the lineal energy (y) domain for both GCR and trapped protons, with the conclusion that the model correctly accounts for the increase in flux at low y values where energetic ions are the primary contributor. We further discuss that, even with the incorporation of angular dependency in the cutoffs, comparison of the GCR differential/integral flux between STS 51 and 114 TEPC measured data and current calculations indicates that there still exists an underestimation by the simulations at low to mid range y values. This underestimation is partly related the exclusion of the secondary pion particle production from the current version of HZETRN.
Optical Observations of GEO Debris with Two Telescopes

NASA Technical Reports Server (NTRS)

Seitzer, P.; Abercromby, K.; Rodriguez, H.; Barker, E.

2007-01-01

For several years, the Michigan Orbital DEbris Survey Telescope (MODEST), the University of Michigan s 0.6/0.9-m Schmidt telescope on Cerro Tololo Inter-American Observatory in Chile has been used to survey the debris population at GEO in the visible regime. Magnitudes, positions, and angular rates are determined for GEO objects as they move across the telescope s field-of-view (FOV) during a 5-minute window. This short window of time is not long enough to determine a full six parameter orbit so usually a circular orbit is assumed. A longer arc of time is necessary to determine eccentricity and to look for changes in the orbit with time. MODEST can follow objects in real-time, but only at the price of stopping survey operations. A second telescope would allow for longer arcs of orbit to obtain the full six orbital parameters, as well as assess the changes over time. An additional benefit of having a second telescope is the capability of obtaining BVRI colors of the faint targets, aiding efforts to determine the material type of faint debris. For 14 nights in March 2007, two telescopes were used simultaneously to observe the GEO debris field. MODEST was used exclusively in survey mode. As objects were detected, they were handed off in near real-time to the Cerro Tololo 0.9-m telescope for follow-up observations. The goal was to determine orbits and colors for all objects fainter than R = 15th magnitude (corresponds to 1 meter in size assuming a 0.2 albedo) detected by MODEST. The hand-off process was completely functional during the final eight nights and follow-ups for objects from night-to-night were possible. The cutoff magnitude level of 15th was selected on the basis of an abrupt change in the observed angular rate distribution in the MODEST surveys. Objects brighter than 15th magnitude tend to lie on a well defined locus in the angular rate plane (and have orbits in the catalog), while fainter objects fill the plane almost uniformly. We need to determine full six-parameter orbits to investigate what causes this change in observed angular rates. Are these faint objects either the same population of high area-to-mass (A/M) objects on eccentric orbits as discovered by the ESA Space Debris Telescope (Schildknecht, et al. 2004), or are they just normal debris from breakups in GEO?
Inner-core Vacillation Cycles during the Intensification of Hurricane Katrina

DTIC Science & Technology

2011-04-01

symmetric overturning circulation draws air from outer radii above the boundary layer while conserving absolute angular momentum. This symmetric...azimuthal momentum by the mean overturning circulation . The resulting increase in the vertical shear of the azimuthal-mean tangential wind that develops in... meridional circulation in a circular vortex. Astrophysica Norvegica 5: 19–60. Elsberry R, Frank W, Holland G, Jarrel J, Southern R. 1987. A Global
Air Force Global Weather Central System Architecture Study. Final System/Subsystem Summary Report. Volume 2. Requirements Compilation and Analysis. Part 1. User and Model Requirements

DTIC Science & Technology

1976-03-01

Milestones will be established after staffing at 6WW. Long-Term Procedures: A capability will be acquired in automated support to Command and Control under... geocentric latitude f = ZttsinQ g = geopotential a = mean radius of earth Ü = angular rotation of the earth 7.29 x 10" rad/sec u,v
High-Altitude, Long-Endurance UAVs vs. Satellites: Potential Benefits for U.S. Army Applications

DTIC Science & Technology

2009-05-01

Refractive Imaging System ....... Point Spread Function ......................... Transmission Characteristics of the Earth’s Atmosphere ...... Scanning...Angle in degrees Commwt Communications Payload Weight p Angular Radius of the Earth in degrees Palbedo Earth’s Albedo Patm Atmospheric Density in...femto-watt (10-15) FY Fiscal Year Gbps Gigabits per Second GBS Global Broadcast System GCS Ground Control Station GEO Geosynchronous Earth Orbit
Scattering for the 3D Gross-Pitaevskii Equation

NASA Astrophysics Data System (ADS)

Guo, Zihua; Hani, Zaher; Nakanishi, Kenji

2017-11-01

We study the Cauchy problem for the 3D Gross-Pitaevskii equation. The global well-posedness in the natural energy space was proved by Gérard (Ann. Inst. H. Poincaré Anal. Non Linéaire 23(5):765-779, 2006). In this paper we prove scattering for small data in the same space with some additional angular regularity, and in particular in the radial case we obtain small energy scattering.
Rotating hairy black holes in arbitrary dimensions

NASA Astrophysics Data System (ADS)

Erices, Cristián; Martínez, Cristián

2018-01-01

A class of exact rotating black hole solutions of gravity nonminimally coupled to a self-interacting scalar field in arbitrary dimensions is presented. These spacetimes are asymptotically locally anti-de Sitter manifolds and have a Ricci-flat event horizon hiding a curvature singularity at the origin. The scalar field is real and regular everywhere, and its effective mass, coming from the nonminimal coupling with the scalar curvature, saturates the Breitenlohner-Freedman bound for the corresponding spacetime dimension. The rotating black hole is obtained by applying an improper coordinate transformation to the static one. Although both spacetimes are locally equivalent, they are globally different, as it is confirmed by the nonvanishing angular momentum of the rotating black hole. It is found that the mass is bounded from below by the angular momentum, in agreement with the existence of an event horizon. The thermodynamical analysis is carried out in the grand canonical ensemble. The first law is satisfied, and a Smarr formula is exhibited. The thermodynamical local stability of the rotating hairy black holes is established from their Gibbs free energy. However, the global stability analysis establishes that the vacuum spacetime is always preferred over the hairy black hole. Thus, the hairy black hole is likely to decay into the vacuum one for any temperature.
Comparison of hydrological and GRACE-based excitation functions of polar motion in the seasonal spectral band

NASA Astrophysics Data System (ADS)

Nastula, J.; Kolaczek, B.; Salstein, D. A.

2008-04-01

Understanding changes in the global balance of the Earths angular momentum due to the mass redistribution of geophysical fluids is needed to explain the observed polar motion. The impact of continental hydrologic signals, from land water, snow, and ice, on polar motion excitation (hydrological angular momentum-HAM), is still inadequately known. Although estimates of HAM have been made from several models of global hydrology based upon the observed distribution of surface water, snow, and soil moisture, the relatively sparse observation network and the presence of errors in the data and the geophysical fluid models preclude a full understanding of the HAM influence on polar motion variations. Recently the GRACE mission monitoring Earths time variable gravity field has allowed us to determine the mass term of polar motion excitation functions and compare them with the mass term derivable as a residual from the geodetic excitation functions and geophysical fluid motion terms on seasonal time scales. Differences between these mass terms in the years 2004 - 2005.5 are still on the order of 20 mas. Besides the overall mass excitation of polar motion comparisons with GRACE (RL04-release), we also intercompare the non-atmospheric, non-oceanic signals in the mass term of geodetic polar motion excitation with hydrological excitation of polar motion.
What sets the central structure of dark matter haloes?

NASA Astrophysics Data System (ADS)

Ogiya, Go; Hahn, Oliver

2018-02-01

Dark matter (DM) haloes forming near the thermal cut-off scale of the density perturbations are unique, since they are the smallest objects and form through monolithic gravitational collapse, while larger haloes contrastingly have experienced mergers. While standard cold dark matter (CDM) simulations readily produce haloes that follow the universal Navarro-Frenk-White (NFW) density profile with an inner slope, ρ ∝ r-α, with α = 1, recent simulations have found that when the free-streaming cut-off expected for the CDM model is resolved, the resulting haloes follow nearly power-law density profiles of α ∼ 1.5. In this paper, we study the formation of density cusps in haloes using idealized N-body simulations of the collapse of proto-haloes. When the proto-halo profile is initially cored due to particle free-streaming at high redshift, we universally find ∼r-1.5 profiles irrespective of the proto-halo profile slope outside the core and large-scale non-spherical perturbations. Quite in contrast, when the proto-halo has a power-law profile, then we obtain profiles compatible with the NFW shape when the density slope of the proto-halo patch is shallower than a critical value, αini ∼ 0.3, while the final slope can be steeper for αini ≳ 0.3. We further demonstrate that the r-1.5 profiles are sensitive to small-scale noise, which gradually drives them towards an inner slope of -1, where they become resilient to such perturbations. We demonstrate that the r-1.5 solutions are in hydrostatic equilibrium, largely consistent with a simple analytic model, and provide arguments that angular momentum appears to determine the inner slope.
Measurement of geomagnetic cutoff rigidities and particle fluxes below geomagnetic cutoff near Palestine, Texas.

NASA Technical Reports Server (NTRS)

Pennypacker, C. R.; Smoot, G. F.; Buffington, A.; Muller, R. A.; Smith, L. H.

1973-01-01

We report a high-statistics magnetic spectrometer measurement of the geomagnetic cutoff rigidity and related effects at Palestine, Texas. The effective cutoffs we observe are in agreement with computer-calculated cutoffs. We also report measured spectra of albedo and atmospheric secondary particles that come below geomagnetic cutoff.
Measurement of geomagnetic cutoff rigidities and particle fluxes below geomagnetic cutoff near Palestine, Texas

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

Pennypacker, C.R.; Smoot, G.F.; Buffington, A.

1973-04-01

A high-statistics magnetic spectrometer measurement of the geomagnetic cutoff rigidity and related effects at Palestine, Texas is reported. The effective cutoffs observed are in agreement with computer-calculated cutoffs. Measured spectra of albedo and atmospheric secondary particles that come below geomagnetic cutoff are also reported. (auth)

Derivation of an optical potential for statically deformed rare-earth nuclei from a global spherical potential

DOE PAGES

Nobre, G. P. A.; Palumbo, A.; Herman, M.; ...

2015-02-25

The coupled-channel theory is a natural way of treating nonelastic channels, in particular those arising from collective excitations characterized by nuclear deformations. A proper treatment of such excitations is often essential to the accurate description of experimental nuclear-reaction data and to the prediction of a wide variety of scattering observables. Stimulated by recent work substantiating the near validity of the adiabatic approximation in coupled-channel calculations for scattering on statically deformed nuclei, we explore the possibility of generalizing a global spherical optical model potential (OMP) to make it usable in coupled-channel calculations on this class of nuclei. To do this, wemore » have deformed the Koning-Delaroche global spherical potential for neutrons, coupling a sufficient number of states of the ground state band to ensure convergence. We present an extensive study of the effects of collective couplings and nuclear deformations on integrated cross sections as well as on angular distributions for neutron-induced reactions on statically deformed nuclei in the rare-earth region. We choose isotopes of three rare-earth elements (Gd, Ho, W), which are known to be nearly perfect rotors, to exemplify the results of the proposed method. Predictions from our model for total, elastic and inelastic cross sections, as well as for elastic and inelastic angular distributions, are in reasonable agreement with measured experimental data. In conclusion, these results suggest that the deformed Koning-Delaroche potential provides a useful regional neutron optical potential for the statically deformed rare earth nuclei.« less
A note on the application of the Prigogine theorem to rotation of tokamak-plasmas in absence of external torques.

PubMed

Sonnino, Giorgio; Cardinali, Alessandro; Sonnino, Alberto; Nardone, Pasquale; Steinbrecher, György; Zonca, Fulvio

2014-03-01

Rotation of tokamak-plasmas, not at the mechanical equilibrium, is investigated using the Prigogine thermodynamic theorem. This theorem establishes that, for systems confined in rectangular boxes, the global motion of the system with barycentric velocity does not contribute to dissipation. This result, suitably applied to toroidally confined plasmas, suggests that the global barycentric rotations of the plasma, in the toroidal and poloidal directions, are pure reversible processes. In case of negligible viscosity and by supposing the validity of the balance equation for the internal forces, we show that the plasma, even not in the mechanical equilibrium, may freely rotate in the toroidal direction with an angular frequency, which may be higher than the neoclassical estimation. In addition, its toroidal rotation may cause the plasma to rotate globally in the poloidal direction at a speed faster than the expression found by the neoclassical theory. The eventual configuration is attained when the toroidal and poloidal angular frequencies reaches the values that minimize dissipation. The physical interpretation able to explain the reason why some layers of plasma may freely rotate in one direction while, at the same time, others may freely rotate in the opposite direction, is also provided. Invariance properties, herein studied, suggest that the dynamic phase equation might be of the second order in time. We then conclude that a deep and exhaustive study of the invariance properties of the dynamical and thermodynamic equations is the most correct and appropriate way for understanding the triggering mechanism leading to intrinsic plasma-rotation in toroidal magnetic configurations.
Una propuesta para el desarrollo de un arreglo de síntesis de apertura

NASA Astrophysics Data System (ADS)

Arnal, E. M.

Los estudios llevados a cabo en la transición del hidrógeno neutro a λ~21-cm han contribuído a incrementar nuestro conocimiento acerca de las propiedades globales del medio interestelar, sea este galáctico o extragaláctico. Avances en este campo han sido provocados, a menudo, por la puesta en servicio de radiotelescopios que poseen una mayor resolución angular. Aquí se presenta una propuesta para desarrollar un nuevo instrumento, un interferómetro, que permitirá abrir nuevas líneas de investigación. Este instrumento combinará la técnica de síntesis de apertura con la de espectroscopía de correlación digital, para alcanzar una resolución angular de 1' y un campo de visión de ~1o.7.
Least-Squares PN Formulation of the Transport Equation Using Self-Adjoint-Angular-Flux Consistent Boundary Conditions

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

Laboure, Vincent M.; Wang, Yaqi; DeHart, Mark D.

In this paper, we study the Least-Squares (LS) PN form of the transport equation compatible with voids [1] in the context of Continuous Finite Element Methods (CFEM).We first deriveweakly imposed boundary conditions which make the LS weak formulation equivalent to the Self-Adjoint Angular Flux (SAAF) variational formulation with a void treatment [2], in the particular case of constant cross-sections and a uniform mesh. We then implement this method in Rattlesnake with the Multiphysics Object Oriented Simulation Environment (MOOSE) framework [3] using a spherical harmonics (PN) expansion to discretize in angle. We test our implementation using the Method of Manufactured Solutionsmore » (MMS) and find the expected convergence behavior both in angle and space. Lastly, we investigate the impact of the global non-conservation of LS by comparing the method with SAAF on a heterogeneous test problem.« less
Least-Squares PN Formulation of the Transport Equation Using Self-Adjoint-Angular-Flux Consistent Boundary Conditions.

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

Vincent M. Laboure; Yaqi Wang; Mark D. DeHart

In this paper, we study the Least-Squares (LS) PN form of the transport equation compatible with voids in the context of Continuous Finite Element Methods (CFEM).We first deriveweakly imposed boundary conditions which make the LS weak formulation equivalent to the Self-Adjoint Angular Flux (SAAF) variational formulation with a void treatment, in the particular case of constant cross-sections and a uniform mesh. We then implement this method in Rattlesnake with the Multiphysics Object Oriented Simulation Environment (MOOSE) framework using a spherical harmonics (PN) expansion to discretize in angle. We test our implementation using the Method of Manufactured Solutions (MMS) and findmore » the expected convergence behavior both in angle and space. Lastly, we investigate the impact of the global non-conservation of LS by comparing the method with SAAF on a heterogeneous test problem.« less
Black hole solutions in d = 5 Chern-Simons gravity

NASA Astrophysics Data System (ADS)

Brihaye, Yves; Radu, Eugen

2013-11-01

The five dimensional Einstein-Gauss-Bonnet gravity with a negative cosmological constant becomes, for a special value of the Gauss-Bonnet coupling constant, a Chern-Simons (CS) theory of gravity. In this work we discuss the properties of several different types of black object solutions of this model. Special attention is paid to the case of spinning black holes with equal-magnitude angular momenta which posses a regular horizon of spherical topology. Closed form solutions are obtained in the small angular momentum limit. Nonperturbative solutions are constructed by solving numerically the equations of the model. Apart from that, new exact solutions describing static squashed black holes and black strings are also discussed. The action and global charges of all configurations studied in this work are obtained by using the quasilocal formalism with boundary counterterms generalized for the case of a d = 5 CS theory.
Dancing with the Muses: dissociation and flow.

PubMed

Thomson, Paula; Jaque, S Victoria

2012-01-01

This study investigated dissociative psychological processes and flow (dispositional and state) in a group of professional and pre-professional dancers (n=74). In this study, high scores for global (Mdn=4.14) and autotelic (Mdn=4.50) flow suggest that dancing was inherently integrating and rewarding, although 17.6% of the dancers were identified as possibly having clinical levels of dissociation (Dissociative Experiences Scale-Taxon cutoff score≥20). The results of the multivariate analysis of variance indicated that subjects with high levels of dissociation had significantly lower levels of global flow (p<.05). Stepwise linear regression analyses demonstrated that dispositional flow negatively predicted the dissociative constructs of depersonalization and taxon (p<.05) but did not significantly predict the variance in absorption/imagination (p>.05). As hypothesized, dissociation and flow seem to operate as different mental processes.
Investigating Various Thresholds as Immunohistochemistry Cutoffs for Observer Agreement.

PubMed

Ali, Asif; Bell, Sarah; Bilsland, Alan; Slavin, Jill; Lynch, Victoria; Elgoweini, Maha; Derakhshan, Mohammad H; Jamieson, Nigel B; Chang, David; Brown, Victoria; Denley, Simon; Orange, Clare; McKay, Colin; Carter, Ross; Oien, Karin A; Duthie, Fraser R

2017-10-01

Clinical translation of immunohistochemistry (IHC) biomarkers requires reliable and reproducible cutoffs or thresholds for interpretation of immunostaining. Most IHC biomarker research focuses on the clinical relevance (diagnostic, prognostic, or predictive utility) of cutoffs, with less emphasis on observer agreement using these cutoffs. From the literature, we identified 3 commonly used cutoffs of 10% positive epithelial cells, 20% positive epithelial cells, and moderate to strong staining intensity (+2/+3 hereafter) to use for investigating observer agreement. A series of 36 images of microarray cores stained for 4 different IHC biomarkers, with variable staining intensity and percentage of positive cells, was used for investigating interobserver and intraobserver agreement. Seven pathologists scored the immunostaining in each image using the 3 cutoffs for positive and negative staining. Kappa (κ) statistic was used to assess the strength of agreement for each cutoff. The interobserver agreement between all 7 pathologists using the 3 cutoffs was reasonably good, with mean κ scores of 0.64, 0.59, and 0.62, respectively, for 10%, 20%, and +2/+3 cutoffs. A good agreement was observed for experienced pathologists using the 10% cutoff, and their agreement was statistically higher than for junior pathologists (P=0.02). In addition, the mean intraobserver agreement for all 7 pathologists using the 3 cutoffs was reasonably good, with mean κ scores of 0.71, 0.60, and 0.73, respectively, for 10%, 20%, and +2/+3 cutoffs. For all 3 cutoffs, a positive correlation was observed with perceived ease of interpretation (P<0.003). Finally, cytoplasmic-only staining achieved higher agreement using all 3 cutoffs than mixed staining patterns. All 3 cutoffs investigated achieve reasonable strength of agreement, modestly decreasing interobserver and intraobserver variability in IHC interpretation. These cutoffs have previously been used in cancer pathology, and this study provides evidence that these cutoffs can be reproducible between practicing pathologists.
Toxoplasma gondii seroprevalence and association with equine protozoal myeloencephalitis: A case-control study of Californian horses.

PubMed

James, K E; Smith, W A; Packham, A E; Conrad, P A; Pusterla, N

2017-06-01

While toxoplasmosis is not commonly considered a clinical disease of equines, previous seroprevalence studies have reported differing background rates of Toxoplasma gondii infection in horses globally. The objective of this study was to evaluate possible associations between T. gondii seroprevalence and clinical signs of equine protozoal myeloencephalitis (EPM) in horses. Using a case-control study design, 720 Californian horses with neurologic signs compatible with EPM were compared to healthy, non-neurologic horses for the presence of T. gondii antibodies (using indirect fluorescent antibody tests [IFAT]). Toxoplasma gondii seroprevalence among cases and controls was determined at standard serum cut-offs: 40, 80, 160, 320, and 640. At a T. gondii titre cut-off of 320, horses with clinical signs compatible with EPM had 3.55 times the odds of a seropositive test compared to those without clinical signs (P<0.01) when adjusted for covariates. When restricted to the autumn season and at the same titre cut-off, an EPM suspect horse had 6.4 times the odds of testing seropositive to T. gondii, compared to non-neurologic horses. The association between high T. gondii titres and clinical signs compatible with EPM is potentially reflective of toxoplasmosis in equines. Serologic testing of cerebrospinal fluid and isolation of T. gondii in EPM suspect cases should be considered. Future studies investigating the relationship between T. gondii and EPM are warranted. Copyright © 2017 Elsevier Ltd. All rights reserved.
The Total Urine Protein-to-Creatinine Ratio Can Predict the Presence of Microalbuminuria

PubMed Central

Yamamoto, Kyoko; Yamamoto, Hiroyuki; Yoshida, Katsumi; Niwa, Koichiro; Nishi, Yutaro; Mizuno, Atsushi; Kuwabara, Masanari; Asano, Taku; Sakoda, Kunihiro; Niinuma, Hiroyuki; Nakahara, Fumiko; Takeda, Kyoko; Shindoh, Chiyohiko; Komatsu, Yasuhiro

2014-01-01

Background The Kidney Disease: Improving Global Outcomes chronic kidney disease (CKD) guidelines recommend that CKD be classified based on the etiology, glomerular filtration rate (GFR) and degree of albuminuria. The present study aimed to establish a method that predicts the presence of microalbuminuria by measuring the total urine protein-to-creatinine ratio (TPCR) in patients with cardiovascular disease (CVD) risk factors. Methods and Results We obtained urine samples from 1,033 patients who visited the cardiovascular clinic at St. Luke's International Hospital from February 2012 to August 2012. We measured the TPCR and the urine albumin-to-creatinine ratio (ACR) from random spot urine samples. We performed correlation, receiver operating characteristic (ROC) curve, sensitivity, and subgroup analyses. There was a strong positive correlation between the TPCR and ACR (R2 = 0.861, p<0.001). A ROC curve analysis for the TPCR revealed a sensitivity of 94.4%, a specificity of 86.1%, and an area under the curve of 0.903 for detecting microalbuminuria for a TPCR cut-off value of 84 mg/g of creatinine. The subgroup analysis indicated that the cut-off value could be used for patients with CVD risk factors. Conclusions These results suggest that the TPCR with an appropriate cut-off value could be used to screen for the presence of microalbuminuria in patients with CVD risk factors. This simple, inexpensive measurement has broader applications, leading to earlier intervention and public benefit. PMID:24614247
Taming cut-off induced artifacts in molecular dynamics studies of solvated polypeptides. The reaction field method.

PubMed

Schreiber, H; Steinhauser, O

1992-12-05

In this paper we present a model system of a solvated polypeptide, which is a suitable reference platform for the systematic exploration of methods for taming artifacts introduced by an incorrect treatment of long-range Coulomb forces. The essential feature of the system composed of an alpha-helical peptide and 1021 water molecules is the strict neutrality of all charge groups. The dynamical properties of the peptide, i.e. unfolding or maintenance of the helix, already give first hints on the influence of boundary effects. A rigorous and deeper insight is gained, however, if analyzing the system by means of the generalized Kirkwood g-factor, which projects the net dipole moment of concentric spheres onto the respective dipole moment of the reference charge group. The g-factor is a global measure for, and a sensitive probe of, the orientational structure, which in its turn reflects even the smallest inconsistencies in the treatment of long-range forces. While the cut-off scheme failed the g-factor test, the "reaction field" method, the simplest cut-off correction scheme, enables a consistent description. In other words, with the aid of the reaction field, the correct orientational structure is restored. As a consequence, the helix stability is regained and we were able to calculate the dielectric constant epsilon approximately 55 to 60 for our system, which is slightly below the corresponding value epsilon SPC = 66 of the pure solvent.
Value of serum N-terminal B-type natriuretic peptide in asymptomatic structural heart disease in Taiwanese population: Comparisons with current ESC Guidelines.

PubMed

Hung, Ta-Chuan; Wang, Kuang-Te; Yun, Chun-Ho; Kuo, Jen-Yuan; Hou, Charles Jia-Yin; Liu, Chia-Yuan; Wu, Tung-Hsin; Bezerra, Hiram G; Cheng, Hsiao-Yang; Hung, Chung-Lieh; Yeh, Hung-I

2017-03-15

The relationship between N-terminal pro-brain natriuretic peptide (NT-proBNP) and cardiac structural or functional anomalies in pre-clinical, asymptomatic Asian populations has not been well identified. From October 2005 to March 2008, we enrolled consecutive asymptomatic adults with preserved global left ventricular (LV) function (ejection fraction>50%) who underwent annual cardiovascular health survey. Circulating NT-proBNP was used to identify echo-defined cardiac structural/functional anomalies and compared to current recommended cut-off from the European Society of Heart Failure. Among 976 eligible subjects, 371 (38%) had structural heart diseases. Echocardiography-based left atrial diameter (Coef: 71.2), diastolic dysfunction (Coef: 35.4), and presence of pulmonary hypertension (Coef: 83.1) or valvular heart disease (Coef: 56.1, all p<0.05) of any form independently predicted circulating NT-ProBNP. NT-ProBNP cut-off values of 32.8 and 115.4pg/ml for subjects aged ≤ and >75years, respectively, demonstrated areas under the receiver operating characteristic curve of 0.76 (95% CI: 0.73-0.80) and 0.70 (95% CI: 0.52-0.88) for predicting structural or functional anomaly. We examined the feasibility of NT-ProBNP for identifying cardiac structural and functional anomaly in an asymptomatic ethnic Taiwanese population with a relatively lower cut-off value, indicating its potential role for pre-clinical screening of Asian patients. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.
Heat transport in Rayleigh-Bénard convection and angular momentum transport in Taylor-Couette flow: a comparative study.

PubMed

Brauckmann, Hannes J; Eckhardt, Bruno; Schumacher, Jörg

2017-03-13

Rayleigh-Bénard convection and Taylor-Couette flow are two canonical flows that have many properties in common. We here compare the two flows in detail for parameter values where the Nusselt numbers, i.e. the thermal transport and the angular momentum transport normalized by the corresponding laminar values, coincide. We study turbulent Rayleigh-Bénard convection in air at Rayleigh number Ra=10 7 and Taylor-Couette flow at shear Reynolds number Re S =2×10 4 for two different mean rotation rates but the same Nusselt numbers. For individual pairwise related fields and convective currents, we compare the probability density functions normalized by the corresponding root mean square values and taken at different distances from the wall. We find one rotation number for which there is very good agreement between the mean profiles of the two corresponding quantities temperature and angular momentum. Similarly, there is good agreement between the fluctuations in temperature and velocity components. For the heat and angular momentum currents, there are differences in the fluctuations outside the boundary layers that increase with overall rotation and can be related to differences in the flow structures in the boundary layer and in the bulk. The study extends the similarities between the two flows from global quantities to local quantities and reveals the effects of rotation on the transport.This article is part of the themed issue 'Toward the development of high-fidelity models of wall turbulence at large Reynolds number'. © 2017 The Author(s).
Anomalies and asymmetries in quark-gluon matter

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

Teryaev, O. V., E-mail: teryaev@theor.jinr.ru

The manifestations of axial anomaly and related effects in heavy-ion collisions are considered. Special role is played by various asymmetries. The azimuthal correlational asymmetries of neutron pairs at NICA/FAIR energy range may probe the global rotation of strongly interacting matter. The conductivity is related to the angular asymmetries of dilepton pairs. The strong magnetic field generated in heavy-ion collisions leads to the excess of soft dileptons flying predominantly in the scattering plane.
Defect in the Joint Spectrum of Hydrogen due to Monodromy.

PubMed

Dullin, Holger R; Waalkens, Holger

2018-01-12

In addition to the well-known case of spherical coordinates, the Schrödinger equation of the hydrogen atom separates in three further coordinate systems. Separating in a particular coordinate system defines a system of three commuting operators. We show that the joint spectrum of the Hamilton operator, the z component of the angular momentum, and an operator involving the z component of the quantum Laplace-Runge-Lenz vector obtained from separation in prolate spheroidal coordinates has quantum monodromy for energies sufficiently close to the ionization threshold. The precise value of the energy above which monodromy is observed depends on the distance of the focus points of the spheroidal coordinates. The presence of monodromy means that one cannot globally assign quantum numbers to the joint spectrum. Whereas the principal quantum number n and the magnetic quantum number m correspond to the Bohr-Sommerfeld quantization of globally defined classical actions a third quantum number cannot be globally defined because the third action is globally multivalued.
Polar motion excitation analysis due to global continental water redistribution

NASA Astrophysics Data System (ADS)

Fernandez, L.; Schuh, H.

2006-10-01

We present the results obtained when studying the hydrological excitation of the Earth‘s wobble due to global redistribution of continental water storage. This work was performed in two steps. First, we computed the hydrological angular momentum (HAM) time series based on the global hydrological model LaD (Land Dynamics model) for the period 1980 till 2004. Then, we compared the effectiveness of this excitation by analysing the residuals of the geodetic time series after removing atmospheric and oceanic contributions with the respective hydrological ones. The emphasis was put on low frequency variations. We also present a comparison of HAM time series from LaD with respect to that one from a global model based on the assimilated soil moisture and snow accumulation data from NCEP/NCAR (The National Center for Environmental Prediction/The National Center for Atmospheric Research) reanalysis. Finally, we evaluate the performance of LaD model in closing the polar motion budget at seasonal periods in comparison with the NCEP and the Land Data Assimilation System (LDAS) models.
Tropical cyclones over the North Indian Ocean: experiments with the high-resolution global icosahedral grid point model GME

NASA Astrophysics Data System (ADS)

Kumkar, Yogesh V.; Sen, P. N.; Chaudhari, Hemankumar S.; Oh, Jai-Ho

2018-02-01

In this paper, an attempt has been made to conduct a numerical experiment with the high-resolution global model GME to predict the tropical storms in the North Indian Ocean during the year 2007. Numerical integrations using the icosahedral hexagonal grid point global model GME were performed to study the evolution of tropical cyclones, viz., Akash, Gonu, Yemyin and Sidr over North Indian Ocean during 2007. It has been seen that the GME model forecast underestimates cyclone's intensity, but the model can capture the evolution of cyclone's intensity especially its weakening during landfall, which is primarily due to the cutoff of the water vapor supply in the boundary layer as cyclones approach the coastal region. A series of numerical simulation of tropical cyclones have been performed with GME to examine model capability in prediction of intensity and track of the cyclones. The model performance is evaluated by calculating the root mean square errors as cyclone track errors.
Multi-source remotely sensed data fusion for improving land cover classification

NASA Astrophysics Data System (ADS)

Chen, Bin; Huang, Bo; Xu, Bing

2017-02-01

Although many advances have been made in past decades, land cover classification of fine-resolution remotely sensed (RS) data integrating multiple temporal, angular, and spectral features remains limited, and the contribution of different RS features to land cover classification accuracy remains uncertain. We proposed to improve land cover classification accuracy by integrating multi-source RS features through data fusion. We further investigated the effect of different RS features on classification performance. The results of fusing Landsat-8 Operational Land Imager (OLI) data with Moderate Resolution Imaging Spectroradiometer (MODIS), China Environment 1A series (HJ-1A), and Advanced Spaceborne Thermal Emission and Reflection (ASTER) digital elevation model (DEM) data, showed that the fused data integrating temporal, spectral, angular, and topographic features achieved better land cover classification accuracy than the original RS data. Compared with the topographic feature, the temporal and angular features extracted from the fused data played more important roles in classification performance, especially those temporal features containing abundant vegetation growth information, which markedly increased the overall classification accuracy. In addition, the multispectral and hyperspectral fusion successfully discriminated detailed forest types. Our study provides a straightforward strategy for hierarchical land cover classification by making full use of available RS data. All of these methods and findings could be useful for land cover classification at both regional and global scales.
Hydrological and oceanic excitations to polar motion andlength-of-day variation

NASA Astrophysics Data System (ADS)

Chen, J. L.; Wilson, C. R.; Chao, B. F.; Shum, C. K.; Tapley, B. D.

2000-04-01

Water mass redistributions in the global hydrosphere, including continental water storage change and non-steric sea level change, introduce variations in the hydrological angular momentum (HAM) and the oceanic angular momentum (OAM). Under the conservation of angular momentum, HAM and OAM variations are significant excitation sources of the Earth rotational variations at a wide range of timescales. In this paper, we estimate HAM and OAM variations and their excitations to polar motion and length-of-day variation using soil moisture and snow estimates andnon-steric sea level change determined by TOPEX/Poseidon satellite radar altimeter observations and a simplified steric sea level change model. The results are compared with the variations of polar motion and LOD that are not accounted for by the atmosphere. This study indicates that seasonal continental water storage change provides significant contributions to both polar motion and LOD variation, especially to polar motion X, and the non-steric sea level change is responsible for a major part of the remaining excitations at both seasonal scale and high frequencies, particularly in polar motion Y and LOD. The good correlation between OAM contributions and the remaining excitations shows that large-scale non-tidal mass variation exists in the oceans and can be detected by TOPEX/Poseidon altimeter observations.
A Two-Phase Space Resection Model for Accurate Topographic Reconstruction from Lunar Imagery with PushbroomScanners

PubMed Central

Xu, Xuemiao; Zhang, Huaidong; Han, Guoqiang; Kwan, Kin Chung; Pang, Wai-Man; Fang, Jiaming; Zhao, Gansen

2016-01-01

Exterior orientation parameters’ (EOP) estimation using space resection plays an important role in topographic reconstruction for push broom scanners. However, existing models of space resection are highly sensitive to errors in data. Unfortunately, for lunar imagery, the altitude data at the ground control points (GCPs) for space resection are error-prone. Thus, existing models fail to produce reliable EOPs. Motivated by a finding that for push broom scanners, angular rotations of EOPs can be estimated independent of the altitude data and only involving the geographic data at the GCPs, which are already provided, hence, we divide the modeling of space resection into two phases. Firstly, we estimate the angular rotations based on the reliable geographic data using our proposed mathematical model. Then, with the accurate angular rotations, the collinear equations for space resection are simplified into a linear problem, and the global optimal solution for the spatial position of EOPs can always be achieved. Moreover, a certainty term is integrated to penalize the unreliable altitude data for increasing the error tolerance. Experimental results evidence that our model can obtain more accurate EOPs and topographic maps not only for the simulated data, but also for the real data from Chang’E-1, compared to the existing space resection model. PMID:27077855

A Two-Phase Space Resection Model for Accurate Topographic Reconstruction from Lunar Imagery with PushbroomScanners.

PubMed

Xu, Xuemiao; Zhang, Huaidong; Han, Guoqiang; Kwan, Kin Chung; Pang, Wai-Man; Fang, Jiaming; Zhao, Gansen

2016-04-11

Exterior orientation parameters' (EOP) estimation using space resection plays an important role in topographic reconstruction for push broom scanners. However, existing models of space resection are highly sensitive to errors in data. Unfortunately, for lunar imagery, the altitude data at the ground control points (GCPs) for space resection are error-prone. Thus, existing models fail to produce reliable EOPs. Motivated by a finding that for push broom scanners, angular rotations of EOPs can be estimated independent of the altitude data and only involving the geographic data at the GCPs, which are already provided, hence, we divide the modeling of space resection into two phases. Firstly, we estimate the angular rotations based on the reliable geographic data using our proposed mathematical model. Then, with the accurate angular rotations, the collinear equations for space resection are simplified into a linear problem, and the global optimal solution for the spatial position of EOPs can always be achieved. Moreover, a certainty term is integrated to penalize the unreliable altitude data for increasing the error tolerance. Experimental results evidence that our model can obtain more accurate EOPs and topographic maps not only for the simulated data, but also for the real data from Chang'E-1, compared to the existing space resection model.
Saturation of the Magnetorotational Instability at Large Elssaser Number

NASA Astrophysics Data System (ADS)

Julien, Keith; Jamroz, Benjamin; Knobloch, Edgar

2009-11-01

The MRI is believed to play an important role in accretion disk physics in extracting angular momentum from the disk and allowing accretion to take place. The instability is investigated within the shearing box approximation under conditions of fundamental importance to astrophysical accretion disk theory. The shear is taken to be the dominant source of energy, but the instability itself requires the presence of a weaker vertical magnetic field. Dissipative effects are suffiently weak that the Elsasser number is large. Thus dissipative forces do not play a role in the leading order linear instability mechanism. However, they are sufficiently large to permit a nonlinear feedback mechanism whereby the turbulent stresses generated by the MRI act on and modify the local background shear in the angular velocity profile. To date this response has been omitted in shearing box simulations and is captured by a reduced pde model derived from the global MHD fluid equations using multiscale asymptotic perturbation theory. Results from simulations of the model indicate a linear phase of exponential growth followed by a nonlinear adjustment to algebraic growth and decay in the fluctuating quantities. Remarkably, the velocity and magnetic field correlations associated with these growth and decay laws conspire to achieve saturation of angular momentum transport.
Global optical model potential for A=3 projectiles

NASA Astrophysics Data System (ADS)

Pang, D. Y.; Roussel-Chomaz, P.; Savajols, H.; Varner, R. L.; Wolski, R.

2009-02-01

A global optical model potential (GDP08) for He3 projectiles has been obtained by simultaneously fitting the elastic scattering data of He3 from targets of 40⩽AT⩽209 at incident energies of 30⩽Einc⩽217 MeV. Uncertainties and correlation coefficients between the global potential parameters were obtained by using the bootstrap statistical method. GDP08 was found to satisfactorily account for the elastic scattering of H3 as well, which makes it a global optical potential for the A=3 nuclei. Optical model calculations using the GDP08 global potential are compared with the experimental angular distributions of differential cross sections for He3-nucleus and H3-nucleus scattering from different targets of 6⩽AT⩽232 at incident energies of 4⩽Einc⩽450 MeV. The optical potential for the doubly-magic nucleus Ca40, the low-energy correction to the real potential for nuclei with 58≲AT≲120 at Einc<30 MeV, the comparison with double-folding model calculations and the CH89 potential, and the spin-orbit potential parameters are discussed.
It's all relative: ranking the diversity of aquatic bacterial communities.

PubMed

Shaw, Allison K; Halpern, Aaron L; Beeson, Karen; Tran, Bao; Venter, J Craig; Martiny, Jennifer B H

2008-09-01

The study of microbial diversity patterns is hampered by the enormous diversity of microbial communities and the lack of resources to sample them exhaustively. For many questions about richness and evenness, however, one only needs to know the relative order of diversity among samples rather than total diversity. We used 16S libraries from the Global Ocean Survey to investigate the ability of 10 diversity statistics (including rarefaction, non-parametric, parametric, curve extrapolation and diversity indices) to assess the relative diversity of six aquatic bacterial communities. Overall, we found that the statistics yielded remarkably similar rankings of the samples for a given sequence similarity cut-off. This correspondence, despite the different underlying assumptions of the statistics, suggests that diversity statistics are a useful tool for ranking samples of microbial diversity. In addition, sequence similarity cut-off influenced the diversity ranking of the samples, demonstrating that diversity statistics can also be used to detect differences in phylogenetic structure among microbial communities. Finally, a subsampling analysis suggests that further sequencing from these particular clone libraries would not have substantially changed the richness rankings of the samples.
Effect sizes and cut-off points: a meta-analytical review of burnout in latin American countries.

PubMed

García-Arroyo, Jose; Osca Segovia, Amparo

2018-05-02

Burnout is a highly prevalent globalized health issue that causes significant physical and psychological health problems. In Latin America research on this topic has increased in recent years, however there are no studies comparing results across countries, nor normative reference cut-offs. The present meta-analysis examines the intensity of burnout (emotional exhaustion, cynicism and personal accomplishment) in 58 adult nonclinical samples from 8 countries (Argentina, Brazil, Chile, Colombia, Ecuador, Mexico, Peru and Venezuela). We found low intensity of burnout but there are significant differences between countries in emotional exhaustion explained by occupation and language. Social and human service professionals (police officers, social workers, public administration staff) are more exhausted than health professionals (physicians, nurses) or teachers. The samples with Portuguese language score higher in emotional exhaustion than Spanish, supporting the theory of cultural relativism. Demographics (sex, age) and study variables (sample size, instrument), were not found significant to predict burnout. The effect size and confidence intervals found are proposed as a useful baseline for research and medical diagnosis of burnout in Latin American countries.
Strong coupling constant from Adler function in lattice QCD

NASA Astrophysics Data System (ADS)

Hudspith, Renwick J.; Lewis, Randy; Maltman, Kim; Shintani, Eigo

2016-09-01

We compute the QCD coupling constant, αs, from the Adler function with vector hadronic vacuum polarization (HVP) function. On the lattice, Adler function can be measured by the differential of HVP at two different momentum scales. HVP is measured from the conserved-local vector current correlator using nf = 2 + 1 flavor Domain Wall lattice data with three different lattice cutoffs, up to a-1 ≈ 3.14 GeV. To avoid the lattice artifact due to O(4) symmetry breaking, we set the cylinder cut on the lattice momentum with reflection projection onto vector current correlator, and it then provides smooth function of momentum scale for extracted HVP. We present a global fit of the lattice data at a justified momentum scale with three lattice cutoffs using continuum perturbation theory at 𝒪(αs4) to obtain the coupling in the continuum limit at arbitrary scale. We take the running to Z boson mass through the appropriate thresholds, and obtain αs(5)(MZ) = 0.1191(24)(37) where the first is statistical error and the second is systematic one.
Effective Alphas and Mixing for Disks with Gravitational Instabilities: Convergence Testing in Global 3D Simulations

NASA Astrophysics Data System (ADS)

Michael, Scott A.; Steiman-Cameron, T.; Durisen, R.; Boley, A.

2008-05-01

Using 3D simulations of a cooling disk undergoing gravitational instabilities (GIs), we compute the effective Shakura and Sunyaev (1973) alphas due to gravitational torques and compare them to predictions from an analytic local theory for thin disks by Gammie (2001). Our goal is to determine how accurately a locally defined alpha can characterize mass and angular momentum transport by GIs in disks. Cases are considered both with cooling by an imposed constant global cooling time (Mejia et al. 2005) and with realistic radiative transfer (Boley et al. 2007). Grid spacing in the azimuthal direction is varied to investigate how the computed alpha is affected by numerical resolution. The azimuthal direction is particularly important, because higher resolution in azimuth allows GI power to spread to higher-order (multi-armed) modes that behave more locally. We find that, in many important respects, the transport of mass and angular momentum by GIs is an intrinsically global phenomenon. Effective alphas are variable on a dynamic time scale over global spatial scales. Nevertheless, preliminary results at the highest resolutions for an imposed cooling time show that our computed alphas, though systematically higher, tend on average to follow Gammie's prediction to within perhaps a factor of two. Our computed alphas include only gravitational stresses, while in Gammie's treatment the effective alpha is due equally to hydrodynamic (Reynolds) and gravitational stresses. So Gammie's prediction may significantly underestimate the true average stresses in a GI-active disk. Our effective alphas appear to be reasonably well converged for 256 and 512 azimuthal zones. We also have a high-resolution simulation under way to test the extent of radial mixing by GIs of gas and its entrained dust for comparison with Stardust observations. Results will be presented if available at the time of the meeting.
Theoretical and Observational Determination of Global and Regional Radiation Budget, Forcing and Feedbacks at the Top-of-Atmosphere and Surface

NASA Technical Reports Server (NTRS)

Loeb, Norman G.

2004-01-01

Report consists of: 1. List of accomplishments 2. List of publications 3. Abstracts of published or submitted papers and 4. Subject invention disclosure. The accomplishments of the grant listed are: 1. Improved the third-order turbulence closure in cloud resolving models to remove the liquid water oscillation. 2. Used the University of California-Los Angeles (UCLA) large-eddy simulation (LES) model to provide data for radiation transfer testing. 3. Revised shortwave k-distribution models based on HITRAN 2000. 4. Developed a gamma-weighted two-stream radiative transfer model for radiation budget estimate applications. 5. Estimated the effect of spherical geometry to the earth radiation budget. 6. Estimated top-of-atmosphere irradiance over snow and sea ice surfaces. 7. Estimated the aerosol direct radiative effect at the top of the atmosphere. 8. Estimated the top-of-atmosphere reflectance of the clear-sky molecular atmosphere over ocean. 9. Developed and validated new set of Angular Distribution Models for the CERES TRMM satellite instrument (tropical) 10. Developed and validated new set of Angular Distribution Models for the CERES Terra satellite instrument (global) 11. Quantified the top-of-atmosphere direct radiative effect of aerosols over global oceans from merged CERES and MODIS observations 12 Clarified the definition of TOA flux reference level for radiation budget studies 13. Developed new algorithm for unfaltering CERES measured radiances 14. Used multiangle POLDER measurements to produce narrowband angular distribution models and examine the effect of scene identification errors on TOA albedo estimates 15. Developed and validated a novel algorithm called the Multidirectional Reflectance Matching (MRM) model for inferring TOA albedos from ice clouds using multi-angle satellite measurements. 16. Developed and validated a novel algorithm called the Multidirectional Polarized Reflectance Matching (MPRM) model for inferring particle shapes from ice clouds using multi-angle polarized satellite measurements. 17. Developed 4 advanced light scattering models including the three-dimensional (3D) uniaxial perfectly matched layer (UPML) finite-difference time-domain (FDTD) model. 18. Develop sunglint in situ measurement and study reflectance distribution in the sunglint area. 19. Lead a balloon-borne radiometer TOA albedo validation effort. 20. Developed a CERES surface UVB, UVA, and UV index product.
Sensing power transfer between the human body and the environment.

PubMed

Veltink, Peter H; Kortier, Henk; Schepers, H Martin

2009-06-01

The power transferred between the human body and the environment at any time and the work performed are important quantities to be estimated when evaluating and optimizing the physical interaction between the human body and the environment in sports, physical labor, and rehabilitation. It is the objective of the current paper to present a concept for estimating power transfer between the human body and the environment during free motions and using sensors at the interface, not requiring measurement systems in the environment, and to experimentally demonstrate this principle. Mass and spring loads were moved by hand over a fixed height difference via varying free movement trajectories. Kinematic and kinetic quantities were measured in the handle between the hand and the load. 3-D force and moments were measured using a 6 DOF force/moment sensor module, 3-D movement was measured using 3-D accelerometers and angular velocity sensors. The orientation was estimated from the angular velocity, using the initial orientation as a begin condition. The accelerometer signals were expressed in global coordinates using this orientation information. Velocity was estimated by integrating acceleration in global coordinates, obtained by adding gravitational acceleration to the accelerometer signals. Zero start and end velocities were used as begin and end conditions. Power was calculated as the sum of the inner products of velocity and force and of angular velocity and moment, and work was estimated by integrating power over time. The estimated performed work was compared to the potential energy difference corresponding to the change in height of the loads and appeared to be accurate within 4% for varying movements with net displacements and varying loads (mass and spring). The principle of estimating power transfer demonstrated in this paper can be used in future interfaces between the human body and the environment instrumented with body-mounted miniature 3-D force and acceleration sensors.
A Modern Picture of Barred Galaxy Dynamics

NASA Astrophysics Data System (ADS)

Petersen, Michael; Weinberg, Martin; Katz, Neal

2018-01-01

Observations of disk galaxies suggest that bars are responsible for altering global galaxy parameters (e.g. structures, gas fraction, star formation rate). The canonical understanding of the mechanisms underpinning bar-driven secular dynamics in disk galaxies has been largely built upon the analysis of linear theory, despite galactic bars being clearly demonstrated to be nonlinear phenomena in n-body simulations. We present simulations of barred Milky Way-like galaxy models designed to elucidate nonlinear barred galaxy dynamics. We have developed two new methodologies for analyzing n-body simulations that give the best of both powerful analytic linear theory and brute force simulation analysis: orbit family identification and multicomponent torque analysis. The software will be offered publicly to the community for their own simulation analysis.The orbit classifier reveals that the details of kinematic components in galactic disks (e.g. the bar, bulge, thin disk, and thick disk components) are powerful discriminators of evolutionary paradigms (i.e. violent instabilities and secular evolution) as well as the basic parameters of the dark matter halo (mass distribution, angular momentum distribution). Multicomponent torque analysis provides a thorough accounting of the transfer of angular momentum between orbits, global patterns, and distinct components in order to better explain the underlying physics which govern the secular evolution of barred disk galaxies.Using these methodologies, we are able to identify the successes and failures of linear theory and traditional n-body simulations en route to a detailed understanding of the control bars exhibit over secular evolution in galaxies. We present explanations for observed physical and velocity structures in observations of barred galaxies alongside predictions for how structures will vary with dynamical properties from galaxy to galaxy as well as over the lifetime of a galaxy, finding that the transfer of angular momentum through previously unidentified channels can more fully explain the observed dynamics.
The Moon and Phobos: specific responses of two satellites moving off and nearer their respective planets

NASA Astrophysics Data System (ADS)

Kochemasov, Gennady Gregory

2016-10-01

Two enigmatic structural and petrologic features of two satellites are widely discussed: origin and global spreading of high-Ti lunar basalts and intercrossing ripples of Phobos. The rippling covers the whole surface of this small satellite constantly moving towards Mars, thus narrowing its orbit and increasing its orbital frequency and speed of rotation. The increasing speed of rotation means increasing angular momentum of Phobos and this must be compensated by diminishing radius. Very "fresh" overall rippling cutting majority of structural forms of Phobos is a trace of this global contracting process. Another trend is in the moving off Moon. Loosing its angular momentum due to slowing rotation a necessary compensation is fulfilled by sending dense basaltic lava into the crust. Varying density basalt flows (high, low, very low-Ti) reflect various stages of the slowing rotation process. Various contents of dense mineral component - ilmenite in basalts means various densities of the rock. Iron in basalts can be in less dense dark minerals and denser ilmenite thus influencing overall basalt densities corresponding to requirements of "healing" diminishing angular momentum. Spectral mapping of basalt types [3] indicate that for large parts of Oceanus Procellarum younger basalts are more titanium rich than the older basalts, thus somewhat reversing the trend found in the returned samples [2]. In some smaller basins spectral mapping also shows titanium richer basalts being older than titanium pure ones [1]. Thus, one may conclude that decreasing rotation rate of the Moon was not smooth but rather uneven. References: [1] H. Hiesinger, R. Jaumann, G.Neukum, J,W. Head, III. Ages of mare basalts on the lunar nearside // J.Geoph.Res., 2000, v.185, #E12, 29239-275. [2] H.Hiesinger and J.W. Head III. Ages of Oceanus Procellarum basalts and other nearside mare basalts //Workshop on New Views of the Moon II, 2016, abs.8030.[3] Pieters C.M.// Proc. Lunar Planet. Sci. Conf., 9th, 1978, 2825-2849.
Jet shapes in dijet events at the LHC in SCET

NASA Astrophysics Data System (ADS)

Hornig, Andrew; Makris, Yiannis; Mehen, Thomas

2016-04-01

We consider the class of jet shapes known as angularities in dijet production at hadron colliders. These angularities are modified from the original definitions in e + e - collisions to be boost invariant along the beam axis. These shapes apply to the constituents of jets defined with respect to either k T -type (anti- k T , C/ A, and k T ) algorithms and cone-type algorithms. We present an SCET factorization formula and calculate the ingredients needed to achieve next-to-leading-log (NLL) accuracy in kinematic regions where non-global logarithms are not large. The factorization formula involves previously unstudied "unmeasured beam functions," which are present for finite rapidity cuts around the beams. We derive relations between the jet functions and the shape-dependent part of the soft function that appear in the factorized cross section and those previously calculated for e + e - collisions, and present the calculation of the non-trivial, color-connected part of the soft-function to O({α}_s) . This latter part of the soft function is universal in the sense that it applies to any experimental setup with an out-of-jet p T veto and rapidity cuts together with two identified jets and it is independent of the choice of jet (sub-)structure measurement. In addition, we implement the recently introduced soft-collinear refactorization to resum logarithms of the jet size, valid in the region of non-enhanced non-global logarithm effects. While our results are valid for all 2 → 2 channels, we compute explicitly for the qq' → qq' channel the color-flow matrices and plot the NLL resummed differential dijet cross section as an explicit example, which shows that the normalization and scale uncertainty is reduced when the soft function is refactorized. For this channel, we also plot the jet size R dependence, the p T cut dependence, and the dependence on the angularity parameter a.
Jet shapes in dijet events at the LHC in SCET

DOE PAGES

Hornig, Andrew; Makris, Yiannis; Mehen, Thomas

2016-04-15

Here, we consider the class of jet shapes known as angularities in dijet production at hadron colliders. These angularities are modified from the original definitions in e + e- collisions to be boost invariant along the beam axis. These shapes apply to the constituents of jets defined with respect to either k T-type (anti-k T, C/A, and k T) algorithms and cone-type algorithms. We present an SCET factorization formula and calculate the ingredients needed to achieve next-to-leading-log (NLL) accuracy in kinematic regions where non-global logarithms are not large. The factorization formula involves previously unstudied “unmeasured beam functions,” which are present for finite rapidity cuts around the beams. We derive relations between the jet functions and the shape-dependent part of the soft function that appear in the factorized cross section and those previously calculated for e +e - collisions, and present the calculation of the non-trivial, color-connected part of the soft-function to O(αs) . This latter part of the soft function is universal in the sense that it applies to any experimental setup with an out-of-jet p T veto and rapidity cuts together with two identified jets and it is independent of the choice of jet (sub-)structure measurement. In addition, we implement the recently introduced soft-collinear refactorization to resum logarithms of the jet size, valid in the region of non-enhanced non-global logarithm effects. While our results are valid for all 2 → 2 channels, we compute explicitly for the qq' → qq' channel the color-flow matrices and plot the NLL resummed differential dijet cross section as an explicit example, which shows that the normalization and scale uncertainty is reduced when the soft function is refactorized. For this channel, we also plot the jet size R dependence, the pmore » $$cut\\atop{T}$$ dependence, and the dependence on the angularity parameter a.« less
The cutoff phenomenon in finite Markov chains.

PubMed Central

Diaconis, P

1996-01-01

Natural mixing processes modeled by Markov chains often show a sharp cutoff in their convergence to long-time behavior. This paper presents problems where the cutoff can be proved (card shuffling, the Ehrenfests' urn). It shows that chains with polynomial growth (drunkard's walk) do not show cutoffs. The best general understanding of such cutoffs (high multiplicity of second eigenvalues due to symmetry) is explored. Examples are given where the symmetry is broken but the cutoff phenomenon persists. PMID:11607633
Comparison of regional hydrological excitation of polar motion derived from hydrological models and the GRACE gravity field data

NASA Astrophysics Data System (ADS)

Nastula, J.; Kolaczek, B.; Salstein, D. A.

2009-09-01

Global geophysical excitation functions of polar motion do not explain fully the observed polar motion as determined by geodetic techniques. The impact of continental hydrologic signals, from land water, snow, and ice, on polar motion excitation HAM (Hydrological Angular Momentum), is still inadequately estimated and not known so well as atmospheric and oceanic ones. Recently the GRACE (Gravity Recovery and Climate Experiment) satellite mission monitoring Earth's time variable gravity field has allowed us to determine global mass term of the polar motion excitation functions, which inherently includes the atmospheric, oceanic and hydrological portions. We use these terms to make comparisons with the mass term of the geodetic and geophysical excitation functions of polar motion on seasonal scales. Global GRACE excitation function of polar motion and hydrological excitation function of polar motion have been determined and were studied earlier
Relativistic impulse dynamics.

PubMed

Swanson, Stanley M

2011-08-01

Classical electrodynamics has some annoying rough edges. The self-energy of charges is infinite without a cutoff. The calculation of relativistic trajectories is difficult because of retardation and an average radiation reaction term. By reconceptuallizing electrodynamics in terms of exchanges of impulses rather than describing it by forces and potentials, we eliminate these problems. A fully relativistic theory using photonlike null impulses is developed. Numerical calculations for a two-body, one-impulse-in-transit model are discussed. A simple relationship between center-of-mass scattering angle and angular momentum was found. It reproduces the Rutherford cross section at low velocities and agrees with the leading term of relativistic distinguishable-particle quantum cross sections (Møller, Mott) when the distance of closest approach is larger than the Compton wavelength of the particle. Magnetism emerges as a consequence of viewing retarded and advanced interactions from the vantage point of an instantaneous radius vector. Radiation reaction becomes the local conservation of energy-momentum between the radiating particle and the emitted impulse. A net action is defined that could be used in developing quantum dynamics without potentials. A reinterpretation of Newton's laws extends them to relativistic motion.
Observation and studies of jet quenching in PbPb collisions at nucleon-nucleon center-of-mass energy = 2.76 TeV

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

Chatrchyan, Serguei; et al.

Jet production in PbPb collisions at a nucleon-nucleon center-of-mass energy of 2.76 TeV was studied with the CMS detector at the LHC, using a data sample corresponding to an integrated luminosity of 6.7 inverse microbarns. Jets are reconstructed using the energy deposited in the CMS calorimeters and studied as a function of collision centrality. With increasing collision centrality, a striking imbalance in dijet transverse momentum is observed, consistent with jet quenching. The observed effect extends from the lower cut-off used in this study (jet transverse momentum = 120 GeV/c) up to the statistical limit of the available data sample (jetmore » transverse momentum approximately 210 GeV/c). Correlations of charged particle tracks with jets indicate that the momentum imbalance is accompanied by a softening of the fragmentation pattern of the second most energetic, away-side jet. The dijet momentum balance is recovered when integrating low transverse momentum particles distributed over a wide angular range relative to the direction of the away-side jet.« less
Measurement of the cross sections of the reactions e +e - → γγ and e +e - → γγγ at LEP

NASA Astrophysics Data System (ADS)

Akwawy, M. Z.; Alexander, G.; Allison, J.; Allport, P. P.; Anderson, K. J.; Armitage, J. C.; Arnison, G. T. J.; Ashton, P.; Azuelos, G.; Baines, J. T. M.; Ball, A. H.; Banks, J.; Barker, G. J.; Barlow, R. J.; Batley, J. R.; Beaudoin, G.; Beck, A.; Becker, J.; Behnke, T.; Bell, K. W.; Bella, G.; Bethke, S.; Biebel, O.; Binder, U.; Bloodworth, I. J.; Bock, P.; Breuker, H.; Brown, R. M.; Brun, R.; Buijs, A.; Burckhart, H. J.; Capiluppi, P.; Carnegie, R. K.; Carter, A. A.; Carter, J. R.; Chang, C. Y.; Charlton, D. G.; Chrin, J. T. M.; Clarke, P. E. L.; Cohen, I.; Collins, W. J.; Conboy, J. E.; Couch, M.; Coupland, M.; Cuffiani, M.; Dado, S.; Dallavalle, G. M.; De Jong, S.; Debu, P.; Deninno, M. M.; Dieckmann, A.; Dittmar, M.; Dixit, M. S.; Duchovni, E.; Duerdoth, I. P.; Dumas, D. J. P.; Elcombe, P. A.; Estabrooks, P. G.; Etzion, E.; Fabbri, F.; Farthouat, P.; Fischer, H. M.; Fong, D. G.; French, M. T.; Fukunaga, C.; Gaidot, A.; Ganel, O.; Gary, J. W.; Gascon, J.; Geddes, N. I.; Gee, C. N. P.; Geich-Gimbel, C.; Gensler, S. W.; Gentit, F. X.; Giacomelli, G.; Gibson, V.; Gibson, W. R.; Gillies, J. D.; Goldberg, J.; Goodrick, M. J.; Gorn, W.; Granite, D.; Gross, E.; Grunhaus, J.; Hagedorn, H.; Hagemann, J.; Hansroul, M.; Hargrove, C. K.; Harrus, I.; Hart, J.; Hattersley, P. M.; Hauschild, M.; Hawkes, C. M.; Heflin, E.; Hemingway, R. J.; Heuer, R. D.; Hill, J. C.; Hillier, S. J.; Hinshaw, D. A.; Ho, C.; Hobbs, J. D.; Hobson, P. R.; Hochman, D.; Holl, B.; Homer, R. J.; Hou, S. R.; Howarth, C. P.; Hughes-Jones, R. E.; Humbert, R.; Igo-Kemenes, P.; Ihssen, H.; Imrie, D. C.; Janissen, L.; Jawahery, A.; Jeffreys, P. W.; Jeremie, H.; Jimack, M.; Jobes, M.; Jones, R. W. L.; Jovanovic, P.; Karlen, D.; Kawagoe, K.; Kawamoto, T.; Kellogg, R. G.; Kennedy, B. W.; Kleinwort, C.; Klem, D. E.; Knop, G.; Kobayashi, T.; Kokott, T. P.; Köpke, L.; Kowalewski, R.; Kreutzmann, H.; Kroll, J.; Kuwano, M.; Kyberd, P.; Lafferty, G. D.; Lamarche, F.; Larson, W. J.; Layter, J. G.; Le Du, P.; Leblanc, P.; Lee, A. M.; Lehto, M. H.; Lellouch, D.; Lennert, P.; Leroy, C.; Lessard, L.; Levegrün, S.; Levinson, L.; Lloyd, S. L.; Loebinger, F. K.; Lorah, J. M.; Lorazo, B.; Losty, M. J.; Ludwig, J.; Ma, J.; Macbeth, A. A.; Mannelli, M.; Marcellini, S.; Maringer, G.; Martin, A. J.; Martin, J. P.; Mashimo, T.; Mättig, P.; Maur, U.; McMahon, T. J.; McNutt, J. R.; Meijers, F.; Menszner, D.; Merritt, F. S.; Mes, H.; Michelini, A.; Middleton, R. P.; Mikenberg, G.; Mildenberger, J.; Miller, D. J.; Milstene, C.; Minowa, M.; Mohr, W.; Moisan, C.; Montanari, A.; Mori, T.; Moss, M. W.; Murphy, P. G.; Murray, W. J.; Nellen, B.; Nguyen, H. H.; Nozaki, M.; O'Dowd, A. J. P.; O'Neale, S. W.; O'Neill, B. P.; Oakham, F. G.; Odorici, F.; Ogg, M.; Oh, H.; Oreglia, M. J.; Orito, S.; Pansart, J. P.; Patrick, G. N.; Pawley, S. J.; Pfister, P.; Pilcher, J. E.; Pinfold, J. L.; Plane, D. E.; Poli, B.; Pouladdej, A.; Prebys, E.; Pritchard, T. W.; Przysiezniak, H.; Quast, G.; Redmond, M. W.; Rees, D. L.; Regimbald, M.; Riles, K.; Roach, C. M.; Robins, S. A.; Rollnik, A.; Roney, J. M.; Rossberg, S.; Rossi, A. M.; Routenburg, P.; Runge, K.; Runolfsson, O.; Sanghera, S.; Sansum, R. A.; Sasaki, M.; Saunders, B. J.; Schaile, A. D.; Schaile, O.; Schappert, W.; Scharff-Hansen, P.; Schreiber, S.; Schwarz, J.; Shapira, A.; Shen, B. C.; Sherwood, P.; Simon, A.; Singh, P.; Siroli, G. P.; Skuja, A.; Smith, A. M.; Smith, T. J.; Snow, G. A.; Springer, R. W.; Sproston, M.; Stephens, K.; Stier, H. E.; Stroehmer, R.; Strom, D.; Takeda, H.; Takeshita, T.; Taras, P.; Thackray, N. J.; Tsukamoto, T.; Turner, M. F.; Tysarczyk-Niemeyer, G.; Van den plas, D.; Van Kooten, R.; VanDalen, G. J.; Vasseur, G.; Virtue, C. J.; von der Schmitt, H.; von Krogh, J.; Wagner, A.; Wahl, C.; Walker, J. P.; Ward, C. P.; Ward, D. R.; Watkins, P. M.; Watson, A. T.; Watson, N. K.; Weber, M.; Weisz, S.; Wells, P. S.; Wermes, N.; Weymann, M.; Wilson, G. W.; Wilson, J. A.; Wingerter, I.; Winterer, V.-H.; Wood, N. C.; Wotton, S.; Wyatt, T. R.; Yaari, R.; Yang, Y.; Yekutieli, G.; Yoshida, T.; Zeuner, W.; Zorn, G. T.; OPAL Collaboration

1991-03-01

The cross section of the pure QED process e +e -→ γγ has been measured using data accumulated during the 1989 and 1990 scans of the Z 0 resonance at LEP. Both the energy dependence and the angular distribution are in good agreement with the QED prediction. Upper limits on the branching ratios of Z 0→ γγ, Z 0→ π0γ and Z 0→ ηγ have been set at 1.4×10 -4, 1.4×10 -4 and 2.0×10 -4 respectively. Lower limits on the cutoff parameters of the modified electron propagator have been found to be Λ+ > 117 GeV and Λ- > 110 GeV. The reaction e +e - → γγγ has also been studied and was found to be consistent with the QED prediction. An upper limit on the branching ratio of Z 0→ γγγ has been set at 6.6 × 10 -5. All the limits are given at 95% confidence level.
Properties of {sup 112}Cd from the (n,n'{gamma}) reaction: Levels and level densities

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

Garrett, P. E.; Lehmann, H.; Jolie, J.

2001-08-01

Levels in {sup 112}Cd have been studied through the (n,n'{gamma}) reaction with monoenergetic neutrons. An extended set of experiments that included excitation functions, {gamma}-ray angular distributions, and {gamma}{gamma} coincidence measurements was performed. A total of 375 {gamma} rays were placed in a level scheme comprising 200 levels (of which 238 {gamma}-ray assignments and 58 levels are newly established) up to 4 MeV in excitation. No evidence to support the existence of 47 levels as suggested in previous studies was found, and these have been removed from the level scheme. From the results, a comparison of the level density is mademore » with the constant temperature and back-shifted Fermi gas models. The back-shifted Fermi gas model with the Gilbert-Cameron spin cutoff parameter provided the best overall fit. Without using the neutron resonance information and only fitting the cumulative number of low-lying levels, the level density parameters extracted are a sensitive function of the maximum energy used in the fit.« less
Risk of mortality associated with neonatal hypothermia in southern Nepal.

PubMed

Mullany, Luke C; Katz, Joanne; Khatry, Subarna K; LeClerq, Steven C; Darmstadt, Gary L; Tielsch, James M

2010-07-01

To quantify the neonatal mortality/hypothermia relationship and develop evidence-based cutoffs for global definitions of neonatal hypothermia. Cohort study. Field workers recorded neonatal axillary temperature at home and recorded vital status at 28 days. Rural Nepal. Twenty-three thousand two hundred forty infants in Sarlahi, Nepal. Hypothermia. Mortality risk was estimated using binomial regression models. Infants were classified using (1) World Health Organization (WHO) cutoffs for mild, moderate, and severe hypothermia; (2) quarter-degree intervals from 32.0 degrees C to 36.5 degrees C; and (3) continuous temperatures. Estimates were adjusted for age, ambient temperature, and other potential confounders. Mortality increased among mild (relative risk [RR], 1.70; 95% confidence interval [CI], 1.23-2.35]), moderate (RR, 4.66; 95% CI, 3.47-6.24]), and severe (RR, 23.36; 95% CI, 4.31-126.70]) hypothermia cases. Within the WHO's moderate classification, risk relative to normothermic infants ranged from 2 to 30 times. Adjusted mortality risk increased 80% (95% CI, 63%-100%) for each degree decrease, was strongly associated with temperatures below 35.0 degrees C (RR, 6.11; 95% CI, 3.98-9.38), and was substantially higher among preterm infants (RR, 12.02; 95% CI, 6.23-23.18]) compared with full-term infants (RR, 3.12; 95% CI, 1.75-5.57). Relative risk was highest in the first 7 days, but remained elevated through 28 days. A new hypothermia classification system should be considered by the WHO for global guidelines. We recommend that grade 1 be equivalent to the current mild category (36.0 degrees C), restricting and splitting the moderate category into grades 2 (35.0 degrees C-36.0 degrees C) and 3 (34.0 degrees C-35.0 degrees C), and expanding severe hypothermia to less than 34.0 degrees C (grade 4). Reducing hypothermia may dramatically decrease the global neonatal mortality burden.

Three-axis stabilization of spacecraft using parameter-independent nonlinear quaternion feedback

NASA Technical Reports Server (NTRS)

Joshi, Suresh M.; Kelkar, Atul G.

1994-01-01

This paper considers the problem of rigid spacecraft. A nonlinear control law which uses the feedback of the unit quaternion and the measured angular velocities is proposed and is shown to provide global asymptotic stability. The control law does not require the knowledge of the system parameters, and is therefore robust to modeling errors. The significance of the control law is that it can be used for large-angle maneuvers with guaranteed stability.
Scalarized hairy black holes

NASA Astrophysics Data System (ADS)

Kleihaus, Burkhard; Kunz, Jutta; Yazadjiev, Stoytcho

2015-05-01

In the presence of a complex scalar field scalar-tensor theory allows for scalarized rotating hairy black holes. We exhibit the domain of existence for these scalarized black holes, which is bounded by scalarized rotating boson stars and hairy black holes of General Relativity. We discuss the global properties of these solutions. Like their counterparts in general relativity, their angular momentum may exceed the Kerr bound, and their ergosurfaces may consist of a sphere and a ring, i.e., form an ergo-Saturn.
A simulation of orientation dependent, global changes in camera sensitivity in ECT

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

Bieszk, J.A.; Hawman, E.G.; Malmin, R.E.

1984-01-01

ECT promises the abilities to: 1) observe radioisotope distributions in a patient without the summation of overlying activity to reduce contrast, and 2) measure quantitatively these distributions to further and more accurately assess organ function. Ideally, camera-based ECT systems should have a performance that is independent of camera orientation or gantry angle. This study is concerned with ECT quantitation errors that can arise from angle-dependent variations of camera sensitivity. Using simulated phantoms representative of heart and liver sections, the effects of sensitivity changes on reconstructed images were assessed both visually and quantitatively based on ROI sums. The sinogram for eachmore » test image was simulated with 128 linear digitization and 180 angular views. The global orientation-dependent sensitivity was modelled by applying an angular sensitivity dependence to the sinograms of the test images. Four sensitivity variations were studied. Amplitudes of 0% (as a reference), 5%, 10%, and 25% with a costheta dependence were studied as well as a cos2theta dependence with a 5% amplitude. Simulations were done with and without Poisson noise to: 1) determine trends in the quantitative effects as a function of the magnitude of the variation, and 2) to see how these effects are manifested in studies having statistics comparable to clinical cases. For the most realistic sensitivity variation (costheta, 5% ampl.), the ROIs chosen in the present work indicated changes of <0.5% in the noiseless case and <5% for the case with Poisson noise. The effects of statistics appear to dominate any effects due to global, sinusoidal, orientation-dependent sensitivity changes in the cases studied.« less
Large-scale clustering as a probe of the origin and the host environment of fast radio bursts

NASA Astrophysics Data System (ADS)

Shirasaki, Masato; Kashiyama, Kazumi; Yoshida, Naoki

2017-04-01

We propose to use degree-scale angular clustering of fast radio bursts (FRBs) to identify their origin and the host galaxy population. We study the information content in autocorrelation of the angular positions and dispersion measures (DM) and in cross-correlation with galaxies. We show that the cross-correlation with Sloan Digital Sky Survey (SDSS) galaxies will place stringent constraints on the mean physical quantities associated with FRBs. If ˜10 ,000 FRBs are detected with ≲deg resolution in the SDSS field, the clustering analysis with the intrinsic DM scatter of 100 pc /cm3 can constrain the global abundance of free electrons at z ≲1 and the large-scale bias of FRB host galaxies (the statistical relation between the distribution of host galaxies and cosmic matter density field) with fractional errors (with a 68% confidence level) of ˜10 % and ˜20 %, respectively. The mean near-source dispersion measure and the delay-time distribution of FRB rates relative to the global star forming rate can be also determined by combining the clustering and the probability distribution function of DM. Our approach will be complementary to high-resolution (≪deg ) event localization using e.g., VLA and VLBI for identifying the origin of FRBs and the source environment. We strongly encourage future observational programs such as CHIME, UTMOST, and HIRAX to survey FRBs in the SDSS field.
Applications of the TIROS-N sounding and cloud motion wind enhancement for the FGGE 'special effort'. [Global Weather Experiment

NASA Technical Reports Server (NTRS)

Atlas, R.

1980-01-01

In January of 1978, a panel of experts recommended that a 'special effort' be made to enhance and edit satellite soundings and cloud tracked winds in data sparse regions. It was felt that these activities would be necessary to obtain maximum benefits from an evaluation of satellite data during the Global Weather Experiment (FGGE). The 'special effort' is being conducted for the two special observing periods of FGGE. More than sixty cases have been selected for enhancement on the basis of meteorological interest. These cases include situations of blocking, cutoff low development, cyclogenesis, and tropical circulations. The sounding data enhancement process consists of supplementing the operational satellite sounding data set with higher resolution soundings in meteorologically active regions, and with new soundings where data voids or soundings of questionable quality exist.
Comparisons of regional Hydrological Angular Momentum (HAM) of the different models

NASA Astrophysics Data System (ADS)

Nastula, J.; Kolaczek, B.; Popinski, W.

2006-10-01

In the paper hydrological excitations of the polar motion (HAM) were computed from various hydrological data series (NCEP, ECMWF, CPC water storage and LaD World Simulations of global continental water). HAM series obtained from these four models and the geodetic excitation function GEOD computed from the polar motion COMB03 data were compared in the seasonal spectral band. The results show big differences of these hydrological excitation functions as well as of their spectra in the seasonal spectra band. Seasonal oscillations of the global geophysical excitation functions (AAM + OAM + HAM) in all cases besides the NCEP/NCAR model are smaller than the geodetic excitation function. It means that these models need further improvement and perhaps not only hydrological models need improvements.
Full-wave modeling of EMIC waves near the He + gyrofrequency

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

Kim, Eun -Hwa; Johnson, Jay R.

Electromagnetic ion cyclotron (EMIC) waves are known to be excited by the cyclotron instability associated with hot and anisotropic ion distributions in the equatorial region of the magnetosphere and are thought to play a key role in radiation belt losses. Although detection of these waves at the ground can provide a global view of the EMIC wave environment, it is not clear what signatures, if any, would be expected. One of the significant scientific issues concerning EMIC waves is to understand how these waves are detected at the ground. In order to solve this puzzle, it is necessary to understandmore » the propagation characteristics of the field-aligned EMIC waves, which include polarization reversal, cutoff, resonance, and mode coupling between different wave modes, in a dipolar magnetic field. However, the inability of ray tracing to adequately describe wave propagation near the crossover cutoff-resonance frequencies in multi-ion plasmas is one of reasons why these scientific questions remain unsolved. Using a recently developed 2-D full-wave code that solves the full-wave equations in global magnetospheric geometry, we demonstrate how EMIC waves propagate from the equatorial region to higher magnetic latitude in an electron-proton-He+ plasma. We find that polarization reversal occurs at the crossover frequency from left-hand polarization (LHP) to right-hand (RHP) polarization and such RHP EMIC waves can either propagate to the inner magnetosphere or reflect to the outer magnetosphere at the Buchsbaum resonance location. Lastly, we also find that mode coupling from guided LHP EMIC waves to unguided RHP or LHP waves (i.e., fast mode) occurs.« less
Full-wave modeling of EMIC waves near the He + gyrofrequency

DOE PAGES

Kim, Eun -Hwa; Johnson, Jay R.

2016-01-06

Electromagnetic ion cyclotron (EMIC) waves are known to be excited by the cyclotron instability associated with hot and anisotropic ion distributions in the equatorial region of the magnetosphere and are thought to play a key role in radiation belt losses. Although detection of these waves at the ground can provide a global view of the EMIC wave environment, it is not clear what signatures, if any, would be expected. One of the significant scientific issues concerning EMIC waves is to understand how these waves are detected at the ground. In order to solve this puzzle, it is necessary to understandmore » the propagation characteristics of the field-aligned EMIC waves, which include polarization reversal, cutoff, resonance, and mode coupling between different wave modes, in a dipolar magnetic field. However, the inability of ray tracing to adequately describe wave propagation near the crossover cutoff-resonance frequencies in multi-ion plasmas is one of reasons why these scientific questions remain unsolved. Using a recently developed 2-D full-wave code that solves the full-wave equations in global magnetospheric geometry, we demonstrate how EMIC waves propagate from the equatorial region to higher magnetic latitude in an electron-proton-He+ plasma. We find that polarization reversal occurs at the crossover frequency from left-hand polarization (LHP) to right-hand (RHP) polarization and such RHP EMIC waves can either propagate to the inner magnetosphere or reflect to the outer magnetosphere at the Buchsbaum resonance location. Lastly, we also find that mode coupling from guided LHP EMIC waves to unguided RHP or LHP waves (i.e., fast mode) occurs.« less
Cluster Free Energies from Simple Simulations of Small Numbers of Aggregants: Nucleation of Liquid MTBE from Vapor and Aqueous Phases.

PubMed

Patel, Lara A; Kindt, James T

2017-03-14

We introduce a global fitting analysis method to obtain free energies of association of noncovalent molecular clusters using equilibrated cluster size distributions from unbiased constant-temperature molecular dynamics (MD) simulations. Because the systems simulated are small enough that the law of mass action does not describe the aggregation statistics, the method relies on iteratively determining a set of cluster free energies that, using appropriately weighted sums over all possible partitions of N monomers into clusters, produces the best-fit size distribution. The quality of these fits can be used as an objective measure of self-consistency to optimize the cutoff distance that determines how clusters are defined. To showcase the method, we have simulated a united-atom model of methyl tert-butyl ether (MTBE) in the vapor phase and in explicit water solution over a range of system sizes (up to 95 MTBE in the vapor phase and 60 MTBE in the aqueous phase) and concentrations at 273 K. The resulting size-dependent cluster free energy functions follow a form derived from classical nucleation theory (CNT) quite well over the full range of cluster sizes, although deviations are more pronounced for small cluster sizes. The CNT fit to cluster free energies yielded surface tensions that were in both cases lower than those for the simulated planar interfaces. We use a simple model to derive a condition for minimizing non-ideal effects on cluster size distributions and show that the cutoff distance that yields the best global fit is consistent with this condition.
Cutoff Finder: A Comprehensive and Straightforward Web Application Enabling Rapid Biomarker Cutoff Optimization

PubMed Central

Budczies, Jan; Klauschen, Frederick; Sinn, Bruno V.; Győrffy, Balázs; Schmitt, Wolfgang D.; Darb-Esfahani, Silvia; Denkert, Carsten

2012-01-01

Gene or protein expression data are usually represented by metric or at least ordinal variables. In order to translate a continuous variable into a clinical decision, it is necessary to determine a cutoff point and to stratify patients into two groups each requiring a different kind of treatment. Currently, there is no standard method or standard software for biomarker cutoff determination. Therefore, we developed Cutoff Finder, a bundle of optimization and visualization methods for cutoff determination that is accessible online. While one of the methods for cutoff optimization is based solely on the distribution of the marker under investigation, other methods optimize the correlation of the dichotomization with respect to an outcome or survival variable. We illustrate the functionality of Cutoff Finder by the analysis of the gene expression of estrogen receptor (ER) and progesterone receptor (PgR) in breast cancer tissues. This distribution of these important markers is analyzed and correlated with immunohistologically determined ER status and distant metastasis free survival. Cutoff Finder is expected to fill a relevant gap in the available biometric software repertoire and will enable faster optimization of new diagnostic biomarkers. The tool can be accessed at http://molpath.charite.de/cutoff. PMID:23251644
Geomagnetic cutoffs: A review for space dosimetry applications

NASA Astrophysics Data System (ADS)

Smart, D. F.; Shea, M. A.

1994-10-01

The earth's magnetic field acts as a shield against charged particle radiation from interplanetary space, technically described as the geomagnetic cutoff. The cutoff rigidity problem (except for the dipole special case) has 'no solution in closed form'. The dipole case yields the Stormer equation which has been repeatedly applied to the earth in hopes of providing useful approximations of cutoff rigidities. Unfortunately the earth's magnetic field has significant deviations from dipole geometry, and the Stormer cutoffs are not adequate for most applications. By application of massive digital computer power it is possible to determine realistic geomagnetic cutoffs derived from high order simulation of the geomagnetic field. Using this technique, 'world-grids' of directional cutoffs for the earth's surface and for a limited number of satellite altitudes have been derived. However, this approach is so expensive and time comsuming it is impractical for most spacecraft orbits, and approximations must be used. The world grids of cutoff rigidities are extensively used as lookup tables, normalization points and interpolation aids to estimate the effective geomagnetic cutoff rigidity of a specific location in space. We review the various options for estimating the cutoff rigidity for earth-orbiting satellites.
Very long baseline interferometer measurements of plasma turbulence in the solar wind

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

Takayuki Sakurai; Spangler, S.R.; Armstrong, J.W.

Turbulence in the solar wind plasma was studied using angular broadening measurements of 10 extragalactic compact radio sources (quasars) with a very long baseline interferometer (VLBI) at 4.99 GHz. Unlike other angular broadening studies, the measured broadening size was corrected for intrinsic source structures which were obtained from a separate VLBI observation. The solar elongations of the sources ranged from 18 R{sub S} to 243 R{sub S}, and five sources with elongations {<=} 60 R{sub S} showed varying degrees of broadening. The measured angular sizes are considerably less than predicted by the well-known empirical relationship of Erickson, as well asmore » two other models for strength of scattering as a function of solar elongation. However, the data are in good agreement with a model for the spatial power spectrum of the turbulence proposed by Coles and Harmon. This model consists of a Kolmogorov spectrum at large scales, but with an enhancement of power near the wavenumber corresponding o the ion inertial length. Two of these sources, 1148-001 and 1253-053 (3C279), show substantial differences in the amount of scattering, even though they are at similar solar elongations (29 versus 35 R{sub S}). Data to which the authors have access indicate that the state of the corona along the lines of sight to these sources may have been quite different. Angular broadening measurements with VLBI interferometers currently under development (primarily the very long baseline array) will allow a global view of plasma turbulence out of the ecliptic plane and thus be complementary to the point in situ measurements with Ulysses. 37 refs., 4 figs., 1 tab.« less
An application of PSO algorithm for multi-criteria geometry optimization of printed low-pass filters based on conductive periodic structures

NASA Astrophysics Data System (ADS)

Steckiewicz, Adam; Butrylo, Boguslaw

2017-08-01

In this paper we discussed the results of a multi-criteria optimization scheme as well as numerical calculations of periodic conductive structures with selected geometry. Thin printed structures embedded on a flexible dielectric substrate may be applied as simple, cheap, passive low-pass filters with an adjustable cutoff frequency in low (up to 1 MHz) radio frequency range. The analysis of an electromagnetic phenomena in presented structures was realized on the basis of a three-dimensional numerical model of three proposed geometries of periodic elements. The finite element method (FEM) was used to obtain a solution of an electromagnetic harmonic field. Equivalent lumped electrical parameters of printed cells obtained in such manner determine the shape of an amplitude transmission characteristic of a low-pass filter. A nonlinear influence of a printed cell geometry on equivalent parameters of cells electric model, makes it difficult to find the desired optimal solution. Therefore an optimization problem of optimal cell geometry estimation with regard to an approximation of the determined amplitude transmission characteristic with an adjusted cutoff frequency, was obtained by the particle swarm optimization (PSO) algorithm. A dynamically suitable inertia factor was also introduced into the algorithm to improve a convergence to a global extremity of a multimodal objective function. Numerical results as well as PSO simulation results were characterized in terms of approximation accuracy of predefined amplitude characteristics in a pass-band, stop-band and cutoff frequency. Three geometries of varying degrees of complexity were considered and their use in signal processing systems was evaluated.
Reproducibility of the cutoff probe for the measurement of electron density

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

Kim, D. W.; Oh, W. Y.; You, S. J., E-mail: sjyou@cnu.ac.kr

2016-06-15

Since a plasma processing control based on plasma diagnostics attracted considerable attention in industry, the reproducibility of the diagnostics using in this application has become a great interest. Because the cutoff probe is one of the potential candidates for this application, knowing the reproducibility of the cutoff probe measurement becomes quit important in the cutoff probe application research. To test the reproducibility of the cutoff probe measurement, in this paper, a comparative study among the different cutoff probe measurements was performed. The comparative study revealed remarkable result: the cutoff probe has a great reproducibility for the electron density measurement, i.e.,more » there are little differences among measurements by different probes made by different experimenters. The discussion including the reason for the result was addressed via this paper by using a basic measurement principle of cutoff probe and a comparative experiment with Langmuir probe.« less
Advancements of In-Flight Mass Moment of Inertia and Structural Deflection Algorithms for Satellite Attitude Simulators

DTIC Science & Technology

2015-03-26

pendulum [15] to estimate the MOI. The benefit to this methodology is that instead of a direct comparison to Euler’s equations when using an on-board ACS...the equations of motion of pendulum motion are evaluated to estimate the resistance to angular acceleration. Instead of attempting to compare noisy...sensor data instantaneously when using on-board ACS data, the pendulum oscillation frequency is estimated, which can be globally smoothed for highly
Compensation of Gaussian curvature in developable cones is local

NASA Astrophysics Data System (ADS)

Wang, Jin W.; Witten, Thomas A.

2009-10-01

We use the angular deficit scheme [V. Borrelli, F. Cazals, and J.-M. Morvan, Comput. Aided Geom. Des. 20, 319 (2003)] to determine the distribution of Gaussian curvature in developable cones (d-cones) [E. Cerda, S. Chaieb, F. Melo, and L. Mahadevan, Nature (London) 401, 46 (1999)] numerically. These d-cones are formed by pushing a thin elastic sheet into a circular container. Negative Gaussian curvatures are identified at the rim where the sheet touches the container. Around the rim there are two narrow bands with positive Gaussian curvatures. The integral of the (negative) Gaussian curvature near the rim is almost completely compensated by that of the two adjacent bands. This suggests that the Gauss-Bonnet theorem which constrains the integral of Gaussian curvature globally does not explain the spontaneous curvature cancellation phenomenon [T. Liang and T. A. Witten, Phys. Rev. E 73, 046604 (2006)]. The locality of the compensation seems to increase for decreasing d-cone thickness. The angular deficit scheme also provides a way to confirm the curvature cancellation phenomenon.
User's guide: Nimbus-7 Earth radiation budget narrow-field-of-view products. Scene radiance tape products, sorting into angular bins products, and maximum likelihood cloud estimation products

NASA Technical Reports Server (NTRS)

Kyle, H. Lee; Hucek, Richard R.; Groveman, Brian; Frey, Richard

1990-01-01

The archived Earth radiation budget (ERB) products produced from the Nimbus-7 ERB narrow field-of-view scanner are described. The principal products are broadband outgoing longwave radiation (4.5 to 50 microns), reflected solar radiation (0.2 to 4.8 microns), and the net radiation. Daily and monthly averages are presented on a fixed global equal area (500 sq km), grid for the period May 1979 to May 1980. Two independent algorithms are used to estimate the outgoing fluxes from the observed radiances. The algorithms are described and the results compared. The products are divided into three subsets: the Scene Radiance Tapes (SRT) contain the calibrated radiances; the Sorting into Angular Bins (SAB) tape contains the SAB produced shortwave, longwave, and net radiation products; and the Maximum Likelihood Cloud Estimation (MLCE) tapes contain the MLCE products. The tape formats are described in detail.
BOW TIES IN THE SKY. I. THE ANGULAR STRUCTURE OF INVERSE COMPTON GAMMA-RAY HALOS IN THE FERMI SKY

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

Broderick, Avery E.; Shalaby, Mohamad; Tiede, Paul

2016-12-01

Extended inverse Compton halos are generally anticipated around extragalactic sources of gamma rays with energies above 100 GeV. These result from inverse Compton scattered cosmic microwave background photons by a population of high-energy electron/positron pairs produced by the annihilation of the high-energy gamma rays on the infrared background. Despite the observed attenuation of the high-energy gamma rays, the halo emission has yet to be directly detected. Here, we demonstrate that in most cases these halos are expected to be highly anisotropic, distributing the upscattered gamma rays along axes defined either by the radio jets of the sources or oriented perpendicularmore » to a global magnetic field. We present a pedagogical derivation of the angular structure in the inverse Compton halo and provide an analytic formalism that facilitates the generation of mock images. We discuss exploiting this fact for the purpose of detecting gamma-ray halos in a set of companion papers.« less
Analytical investigation of adaptive control of radiated inlet noise from turbofan engines

NASA Technical Reports Server (NTRS)

Risi, John D.; Burdisso, Ricardo A.

1994-01-01

An analytical model has been developed to predict the resulting far field radiation from a turbofan engine inlet. A feedforward control algorithm was simulated to predict the controlled far field radiation from the destructive combination of fan noise and secondary control sources. Numerical results were developed for two system configurations, with the resulting controlled far field radiation patterns showing varying degrees of attenuation and spillover. With one axial station of twelve control sources and error sensors with equal relative angular positions, nearly global attenuation is achieved. Shifting the angular position of one error sensor resulted in an increase of spillover to the extreme sidelines. The complex control inputs for each configuration was investigated to identify the structure of the wave pattern created by the control sources, giving an indication of performance of the system configuration. It is deduced that the locations of the error sensors and the control source configuration are equally critical to the operation of the active noise control system.
New Estimates of Hydrological and Oceanic Excitations of Variations of Earth's Rotation, Geocenter and Gravitational Field

NASA Technical Reports Server (NTRS)

Chao, Benjamin F.; Chen, J. L.; Johnson, T.; Au, A. Y.

1998-01-01

Hydrological mass transport in the geophysical fluids of the atmosphere-hydrosphere-solid Earth surface system can excite Earth's rotational variations in both length-of-day and polar motion. These effects can be computed in terms of the hydrological angular momentum by proper integration of global meteorological data. We do so using the 40-year NCEP data and the 18-year NASA GEOS-1 data, where the precipitation and evapotranspiration budgets are computed via the water mass balance of the atmosphere based on Oki et al.'s (1995) algorithm. This hydrological mass redistribution will also cause geocenter motion and changes in Earth's gravitational field, which are similarly computed using the same data sets. Corresponding geodynamic effects due to the oceanic mass transports (i.e. oceanic angular momentum and ocean-induced geocenter/gravity changes) have also been computed in a similar manner. We here compare two independent sets of the result from: (1) non-steric ocean surface topography observations based on Topex/Poseidon, and (2) the model output of the mass field by the Parallel Ocean Climate Model. Finally, the hydrological and the oceanic time series are combined in an effort to better explain the observed non-atmospheric effects. The latter are obtained by subtracting the atmospheric angular momentum from Earth rotation observations, and the atmosphere- induced geocenter/gravity effects from corresponding geodetic observations, both using the above-mentioned atmospheric data sets.

Cutoff Probe for Tokamak SOL Measurement

NASA Astrophysics Data System (ADS)

Na, Byung-Keun; You, Kwang-Ho; Kim, Dae-Woong; You, Shin-Jae; Kim, Jung-Hyung; Chang, Hong-Young

2013-09-01

Since a cutoff probe was developed, there have been a lot of improvements in methodology and analysis for low temperature plasmas. However, in order to apply the cutoff probe to the Tokamak scrape-off layer (SOL), three important issues should be solved - speed, thermal protection, and short-distance (a few mm) wave propagation in magnetized plasmas. In this presentation, the improvement of cutoff probe for Tokamak is shown. The above problems can be solved using the following methods: (a) the cutoff probe can be used with short impulse of a few nano-seconds for speed improvement. (b) Ceramic covers were used for thermal protection. (c) In magnetized plasmas, the cutoff peak can be analyzed using circuit modeling and CST Microwave studio. To verify the proposed methods, the cutoff probe was applied to a Helicon plasma, and the results were compared to laser Thomson scattering results. Based on the result in the Helicon plasma, the cutoff probe will be applied to far-SOL region at the KSTAR 2013 campaign, and SOL region at the later campaign.
Current MUAC Cut-Offs to Screen for Acute Malnutrition Need to Be Adapted to Gender and Age: The Example of Cambodia

PubMed Central

Fiorentino, Marion; Sophonneary, Prak; Laillou, Arnaud; Whitney, Sophie; de Groot, Richard; Perignon, Marlène; Kuong, Khov; Berger, Jacques; Wieringa, Frank T.

2016-01-01

Background Early identification of children <5 yrs with acute malnutrition is a priority. Acute malnutrition is defined by the World Health Organization as a mid-upper-arm circumference (MUAC) <12.5 cm or a weight-for-height Z-score (WHZ) <-2. MUAC is a simple and low-cost indicator to screen for acute malnutrition in communities, but MUAC cut-offs currently recommended by WHO do not identify the majority of children with weight-for-height Z-score (<-2 (moderate malnourished) or r<-3 (severe malnourished). Also, no cut-offs for MUAC are established for children >5 yrs. Therefore, this study aimed at defining gender and age-specific cut-offs to improve sensitivity of MUAC as an indicator of acute malnutrition. Methods To establish new age and gender-specific MUAC cut-offs, pooled data was obtained for 14,173 children from 5 surveys in Cambodia (2011–2013). Sensitivity, false positive rates, and areas under receiver-operator characteristic curves (AUC) were calculated using wasting for children <5yrs and thinness for children ≥5yrs as gold standards. Among the highest values of AUC, the cut-off with the highest sensitivity and a false positive rate ≤33% was selected as the optimal cut-off. Results Optimal cut-off values increased with age. Boys had higher cut-offs than girls, except in the 8–10.9 yrs age range. In children <2yrs, the cut-off was lower for stunted children compared to non stunted children. Sensitivity of MUAC to identify WHZ<-2 and <-3 z-scores increased from 24.3% and 8.1% to >80% with the new cut-offs in comparison with the current WHO cut-offs. Conclusion Gender and age specific MUAC cut-offs drastically increased sensitivity to identify children with WHZ-score <-2 z-scores. International reference of MUAC cut-offs by age group and gender should be established to screen for acute malnutrition at the community level. PMID:26840899
Hydrological Excitations of Polar Motion Derived from Different Variables of Fgoals - g2 Climate Model

NASA Astrophysics Data System (ADS)

Winska, M.

2016-12-01

The hydrological contribution to decadal, inter-annual and multi-annual suppress polar motion derived from climate model as well as from GRACE (Gravity Recovery and Climate Experiment) data is discussed here for the period 2002.3-2016.0. The data set used here are Earth Orientation Parameters Combined 04 (EOP C04), Flexible Global Ocean-Atmosphere-Land System Model: Grid-point Version 2 (FGOAL-g2) and Global Land Data Assimilation System (GLDAS) climate models and GRACE CSR RL05 data for polar motion, hydrological and gravimetric excitation, respectively. Several Hydrological Angular Momentum (HAM) functions are calculated here from the selected variables: precipitation, evaporation, runoff, soil moisture, accumulated snow of the FGOALS and GLDAS climate models as well as from the global mass change fields from GRACE data provided by the International Earth Rotation and Reference System Service (IERS) Global Geophysical Fluids Center (GGFC). The contribution of different HAM excitation functions to achieve the full agreement between geodetic observations and geophysical excitation functions of polar motion is studied here.
Whole-brain structural topology in adult attention-deficit/hyperactivity disorder: Preserved global - disturbed local network organization.

PubMed

Sidlauskaite, Justina; Caeyenberghs, Karen; Sonuga-Barke, Edmund; Roeyers, Herbert; Wiersema, Jan R

2015-01-01

Prior studies demonstrate altered organization of functional brain networks in attention-deficit/hyperactivity disorder (ADHD). However, the structural underpinnings of these functional disturbances are poorly understood. In the current study, we applied a graph-theoretic approach to whole-brain diffusion magnetic resonance imaging data to investigate the organization of structural brain networks in adults with ADHD and unaffected controls using deterministic fiber tractography. Groups did not differ in terms of global network metrics - small-worldness, global efficiency and clustering coefficient. However, there were widespread ADHD-related effects at the nodal level in relation to local efficiency and clustering. The affected nodes included superior occipital, supramarginal, superior temporal, inferior parietal, angular and inferior frontal gyri, as well as putamen, thalamus and posterior cerebellum. Lower local efficiency of left superior temporal and supramarginal gyri was associated with higher ADHD symptom scores. Also greater local clustering of right putamen and lower local clustering of left supramarginal gyrus correlated with ADHD symptom severity. Overall, the findings indicate preserved global but altered local network organization in adult ADHD implicating regions underpinning putative ADHD-related neuropsychological deficits.
Determination of the optimal cutoff value for a serological assay: an example using the Johne's Absorbed EIA.

PubMed Central

Ridge, S E; Vizard, A L

1993-01-01

Traditionally, in order to improve diagnostic accuracy, existing tests have been replaced with newly developed diagnostic tests with superior sensitivity and specificity. However, it is possible to improve existing tests by altering the cutoff value chosen to distinguish infected individuals from uninfected individuals. This paper uses data obtained from an investigation of the operating characteristics of the Johne's Absorbed EIA to demonstrate a method of determining a preferred cutoff value from several potentially useful cutoff settings. A method of determining the financial gain from using the preferred rather than the current cutoff value and a decision analysis method to assist in determining the optimal cutoff value when critical population parameters are not known with certainty are demonstrated. The results of this study indicate that the currently recommended cutoff value for the Johne's Absorbed EIA is only close to optimal when the disease prevalence is very low and false-positive test results are deemed to be very costly. In other situations, there were considerable financial advantages to using cutoff values calculated to maximize the benefit of testing. It is probable that the current cutoff values for other diagnostic tests may not be the most appropriate for every testing situation. This paper offers methods for identifying the cutoff value that maximizes the benefit of medical and veterinary diagnostic tests. PMID:8501227
Testing the cosmological principle of isotropy: local power-spectrum estimates of the WMAP data

NASA Astrophysics Data System (ADS)

Hansen, F. K.; Banday, A. J.; Górski, K. M.

2004-11-01

We apply the Gabor transform methodology proposed by Hansen et al. to the WMAP data in order to test the statistical properties of the cosmic microwave background (CMB) fluctuation field and specifically to evaluate the fundamental assumption of cosmological isotropy. In particular, we apply the transform with several apodization scales, thus allowing the determination of the positional dependence of the angular power spectrum with either high spatial localization or high angular resolution (i.e. narrow bins in multipole space). Practically, this implies that we estimate the angular power spectrum locally in discs of various sizes positioned in different directions: small discs allow the greatest sensitivity to positional dependence, whereas larger discs allow greater sensitivity to variations over different angular scales. In addition, we determine whether the spatial position of a few outliers in the angular power spectrum could suggest the presence of residual foregrounds or systematic effects. For multipoles close to the first peak, the most deviant local estimates from the best-fitting WMAP model are associated with a few particular areas close to the Galactic plane. Such deviations also include the `dent' in the spectrum just shortward of the first peak which was remarked upon by the WMAP team. Estimating the angular power spectrum excluding these areas gives a slightly higher first Doppler peak amplitude. Finally, we probe the isotropy of the largest angular scales by estimating the power spectrum on hemispheres and reconfirm strong indications of a north-south asymmetry previously reported by other authors. Indeed, there is a remarkable lack of power in a region associated with the North ecliptic Pole. With the greater fidelity in l-space allowed by this larger sky coverage, we find tentative evidence for residual foregrounds in the range l= 2-4, which could be associated with the low measured quadrupole amplitudes and other anomalies on these angular scales (e.g. planarity and alignment). However, over the range l= 5-40 the observed asymmetry is much harder to explain in terms of residual foregrounds and known systematic effects. By reorienting the coordinate axes, we partition the sky into different hemispheres and search for the reference frame which maximizes the asymmetric distribution of power. The North Pole for this coordinate frame is found to intersect the sphere at (80°, 57°) in Galactic colatitude and longitude over almost the entire multipole range l= 5-40. Furthermore, the strong negative outlier at l= 21 and the strong positive outlier at l= 39, as determined from the global power spectrum by the WMAP team, are found to be associated with the Northern and Southern hemispheres, respectively (in this frame of maximum asymmetry). Thus, these two outliers follow the general tendency of the multipoles l= 5-40 to be of systematically lower amplitude in the north and higher in the south. Such asymmetric distributions of power on the sky provide a serious test for the cosmological principle of isotropy.
Staging dementia using Clinical Dementia Rating Scale Sum of Boxes scores: a Texas Alzheimer's research consortium study.

PubMed

O'Bryant, Sid E; Waring, Stephen C; Cullum, C Munro; Hall, James; Lacritz, Laura; Massman, Paul J; Lupo, Philip J; Reisch, Joan S; Doody, Rachelle

2008-08-01

The Clinical Dementia Rating Scale Sum of Boxes (CDR-SOB) score is commonly used, although the utility regarding this score in staging dementia severity is not well established. To investigate the effectiveness of CDR-SOB scores in staging dementia severity compared with the global CDR score. Retrospective study. Texas Alzheimer's Research Consortium minimum data set cohort. A total of 1577 participants (110 controls, 202 patients with mild cognitive impairment, and 1265 patients with probable Alzheimer disease) were available for analysis. Receiver operating characteristic curves were generated from a derivation sample to determine optimal cutoff scores and ranges, which were then applied to the validation sample. Optimal ranges of CDR-SOB scores corresponding to the global CDR scores were 0.5 to 4.0 for a global score of 0.5, 4.5 to 9.0 for a global score of 1.0, 9.5 to 15.5 for a global score of 2.0, and 16.0 to 18.0 for a global score of 3.0. When applied to the validation sample, kappa scores ranged from 0.86 to 0.94 (P < .001 for all), with 93.0% of the participants falling within the new staging categories. The CDR-SOB score compares well with the global CDR score for dementia staging. Owing to the increased range of values, the CDR-SOB score offers several advantages over the global score, including increased utility in tracking changes within and between stages of dementia severity. Interpretive guidelines for CDR-SOB scores are provided.
Staging Dementia Using Clinical Dementia Rating Scale Sum of Boxes Scores

PubMed Central

O'Bryant, Sid E.; Waring, Stephen C.; Cullum, C. Munro; Hall, James; Lacritz, Laura; Massman, Paul J.; Lupo, Philip J.; Reisch, Joan S.; Doody, Rachelle

2012-01-01

Background The Clinical Dementia Rating Scale Sum of Boxes (CDR-SOB) score is commonly used, although the utility regarding this score in staging dementia severity is not well established. Obiective To investigate the effectiveness of CDRSOB scores in staging dementia severity compared with the global CDR score. Design Retrospective study. Setting Texas Alzheimer's Research Consortium minimum data set cohort. Participants A total of 1577 participants (110 controls, 202 patients with mild cognitive impairment, and 1265 patients with probable Alzheimer disease) were available for analysis. Main Outcome Measures Receiver operating characteristic curves were generated from a derivation sample to determine optimal cutoff scores and ranges, which were then applied to the validation sample. Results Optimal ranges of CDR-SOB scores corresponding to the global CDR scores were 0.5 to 4.0 for a global score of 0.5, 4.5 to 9.0 for a global score of 1.O, 9.5 to 15.5 for a global score of 2.0, and 16.0 to 18.0 for a global score of 3.0. When applied to the validation sample, κ scores ranged from 0.86 to 0.94 (P <.001 for all), with 93.0% of the participants falling within the new staging categories. Conclusions The CDR-SOB score compares well with the global CDR score for dementia staging. Owing to the increased range of values, the CDR-SOB score offers several advantages over the global score, including increased utility in tracking changes within and between stages of dementia severity. Interpretive guidelines for CDR-SOB scores are provided. PMID:18695059
49 CFR 229.93 - Safety cut-off device.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Safety cut-off device. 229.93 Section 229.93 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Equipment § 229.93 Safety cut-off device. The fuel line shall have a safety cut-off device that— (a) Is...
49 CFR 229.93 - Safety cut-off device.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Safety cut-off device. 229.93 Section 229.93 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Equipment § 229.93 Safety cut-off device. The fuel line shall have a safety cut-off device that— (a) Is...
Observation of Global Hyperon Polarization in Ultrarelativistic Heavy-Ion Collisions

NASA Astrophysics Data System (ADS)

Upsal, Isaac; STAR Collaboration

2017-11-01

Collisions between heavy nuclei at ultra-relativistic energies form a color-deconfined state of matter known as the quark-gluon plasma. This state is well described by hydrodynamics, and non-central collisions are expected to produce a fluid characterized by strong vorticity in the presence of strong external magnetic fields. The STAR Collaboration at Brookhaven National Laboratory's Relativistic Heavy Ion Collider (RHIC) has measured collisions between gold nuclei at center of mass energies √{sNN} = 7.7- 200 GeV. We report the first observation of globally polarized Λ and Λ bar hyperons, aligned with the angular momentum of the colliding system. These measurements provide important information on partonic spin-orbit coupling, the vorticity of the quark-gluon plasma, and the magnetic field generated in the collision.
Elastic response of (001)-oriented PWA 1480 single crystal - The influence of secondary orientation

NASA Technical Reports Server (NTRS)

Kalluri, Sreeramesh; Abdul-Azis, Ali; Mcgaw, Michael

1991-01-01

The influence of secondary orientation on the elastic response of a zone axis (001)-oriented nickel-base single-crystal superalloy, PWA 1480, was investigated under mechanical loading conditions by applying finite element techniques. Elastic stress analyses were performed with a commercially available finite element code. Secondary orientation of the single-crystal superalloy was offset with respect to the global coordinate system in increments from 0 to 90 deg and stresses developed within the single crystal were determined for each loading condition. The results indicated that the stresses were strongly influenced by the angular offset between the secondary crystal orientation and the global coordinate system. The degree of influence was found to vary with the type of loading condition (mechanical, thermal, or combined) imposed on the single-crystal superalloy.
Effects of Energy Dissipation in the Sphere-Restricted Full Three-Body Problem

NASA Astrophysics Data System (ADS)

Gabriel, T. S. J.

Recently, the classical N-Body Problem has been adjusted to account for celestial bodies made of constituents of finite density. By imposing a minima on the achievable distance between particles, minimum energy resting states are allowed by the problem. The Full N-Body Problem allows for the dissipation of mechanical energy through surface-surface interactions via impacts or by way of tidal deformation. Barring exogeneous forces and allowing for the dissipation of energy, these systems have discrete, and sometimes multiple, minimum energy states for a given angular momentum. Building the dynamical framework of such finite density systems is a necessary process in outlining the evolution of rubble pile asteroids and other gravitational-granular systems such as protoplanetary discs, and potentially planetary rings, from a theoretical point of view. In all cases, resting states are expected to occur as a necessary step in the ongoing processes of solar system formation and evolution. Previous studies of this problem have been performed in the N=3 case where the bodies are indistinguishable spheres, with all possible relative equilibria and their stability having been identified as a function of the angular momentum of the system. These studies uncovered that at certain levels of angular momentum there exists two minimum energy states, a global and local minimum. Thus a question of interest is in which of these states a dissipative system would preferentially settle and the sensitivity of results to changes in dissipation parameters. Assuming equal-sized, perfectly-rigid bodies, this study investigates the dynamical evolution of three spheres under the influence of mutual gravity and impact mechanics as a function of dissipation parameters. A purpose-written, C-based, Hard Sphere Discrete Element Method code has been developed to integrate trajectories and resolve contact mechanics as grains evolve into minimum energy configurations. By testing many randomized initial conditions, statistics are measured regarding minimum energy states for a given angular momentum range. A trend in the Sphere-Restricted Full Three-Body Problem producing an end state of one configuration over another is found as a function of angular momentum and restitution.
[Evaluation of peruvian money test in screening of cognitive impairment among older adults].

PubMed

Oscanoa, Teodoro J; Cieza, Edwin; Parodi, José F; Paredes, Napoleón

2016-03-01

Objectives To evaluate the Peruvian adaptation of the money test (Eurotest) for identifying cognitive impairment among >60-year-old adults. Materials and methods This is a phase I study of diagnostic test, with a convenience sampling and calculation of the test´s sensitivity and specificity, based on a pretest prevalence of 50%. The criteria of the Diagnostic and Statistical Manual of Mental Disorders (DSM IV) and Global Deterioration Scale (GDS) were used for the operational definition of patients with cognitive impairment. Receiver operating characteristic (ROC) curve analysis was used to identify the optimal cut-off value. Results The study evaluated 42 cases and 42 controls; there was no significant difference between age (77.88 ± 6.01 years vs. 6.49 76.14 ± years) and years of education (13.69 ± 3.70 years vs. 8.17 ± 4.71 years). The Peruvian version of the Eurotest has a sensitivity of 90.5% and specificity of 83.3% with cut-off value of 24. Conclusions The Peruvian adapted version of the Eurotest, called prueba de la moneda peruana could be useful in screening for cognitive impairment among older adults.
Daily workload in the embryology laboratory and in vitro fertilization results.

PubMed

Expósito, Antonia; Matorras, Roberto; Mendoza, Rosario; Crisol, Lorena; Martínez-Astorquiza, Txanton; Prieto, Begoña

2010-01-01

To ascertain if the daily activity in the in vitro fertilization (IVF) laboratory is related to pregnancy rates (PR) and fertilization rates (FR) in an IVF program. A retrospective study was performed to compare the PR and the FR obtained in 845 oocyte retrievals (OR) and 713 embryo transfers (ET), according to the daily workload. Different cutoffs were established: < or = 3 OR per day vs. > 3 OR per day; < or = 3 ET per day vs. > 3 ET per day, and also a cutoff considering the global activity in 3 different categories: optimal (level I), overload (level II) and high overload (level III), both the day of OR and of ET. The PR on the days with < or = 3 OR and with > 3 OR were similar, as were the days with < or = 3 ET or > 3 ET. There were no differences in PR when the activity the day of OR was level I, II or III (24.4%, 25.2% and 28.3%, respectively) or when the activity on the day of ET was level I, II or III (29.6%, 37.3% and 23.7%, respectively). We failed to show any adverse results on our IVF program associated with the daily workload.
Optimisation of 12 MeV electron beam simulation using variance reduction technique

NASA Astrophysics Data System (ADS)

Jayamani, J.; Termizi, N. A. S. Mohd; Kamarulzaman, F. N. Mohd; Aziz, M. Z. Abdul

2017-05-01

Monte Carlo (MC) simulation for electron beam radiotherapy consumes a long computation time. An algorithm called variance reduction technique (VRT) in MC was implemented to speed up this duration. This work focused on optimisation of VRT parameter which refers to electron range rejection and particle history. EGSnrc MC source code was used to simulate (BEAMnrc code) and validate (DOSXYZnrc code) the Siemens Primus linear accelerator model with the non-VRT parameter. The validated MC model simulation was repeated by applying VRT parameter (electron range rejection) that controlled by global electron cut-off energy 1,2 and 5 MeV using 20 × 107 particle history. 5 MeV range rejection generated the fastest MC simulation with 50% reduction in computation time compared to non-VRT simulation. Thus, 5 MeV electron range rejection utilized in particle history analysis ranged from 7.5 × 107 to 20 × 107. In this study, 5 MeV electron cut-off with 10 × 107 particle history, the simulation was four times faster than non-VRT calculation with 1% deviation. Proper understanding and use of VRT can significantly reduce MC electron beam calculation duration at the same time preserving its accuracy.
Magneto-thermal Disk Winds from Protoplanetary Disks

NASA Astrophysics Data System (ADS)

Bai, Xue-Ning; Ye, Jiani; Goodman, Jeremy; Yuan, Feng

2016-02-01

The global evolution and dispersal of protoplanetary disks (PPDs) are governed by disk angular-momentum transport and mass-loss processes. Recent numerical studies suggest that angular-momentum transport in the inner region of PPDs is largely driven by magnetized disk wind, yet the wind mass-loss rate remains unconstrained. On the other hand, disk mass loss has conventionally been attributed to photoevaporation, where external heating on the disk surface drives a thermal wind. We unify the two scenarios by developing a one-dimensional model of magnetized disk winds with a simple treatment of thermodynamics as a proxy for external heating. The wind properties largely depend on (1) the magnetic field strength at the wind base, characterized by the poloidal Alfvén speed vAp, (2) the sound speed cs near the wind base, and (3) how rapidly poloidal field lines diverge (achieve {R}-2 scaling). When {v}{Ap}\\gg {c}{{s}}, corotation is enforced near the wind base, resulting in centrifugal acceleration. Otherwise, the wind is accelerated mainly by the pressure of the toroidal magnetic field. In both cases, the dominant role played by magnetic forces likely yields wind outflow rates that exceed purely hydrodynamical mechanisms. For typical PPD accretion-rate and wind-launching conditions, we expect vAp to be comparable to cs at the wind base. The resulting wind is heavily loaded, with a total wind mass-loss rate likely reaching a considerable fraction of the wind-driven accretion rate. Implications for modeling global disk evolution and planet formation are also discussed.
10 CFR 26.163 - Cutoff levels for drugs and drug metabolites.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Cutoff levels for drugs and drug metabolites. 26.163... the Department of Health and Human Services § 26.163 Cutoff levels for drugs and drug metabolites. (a) Initial drug testing. (1) HHS-certified laboratories shall apply the following cutoff levels for initial...
10 CFR 26.163 - Cutoff levels for drugs and drug metabolites.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false Cutoff levels for drugs and drug metabolites. 26.163... the Department of Health and Human Services § 26.163 Cutoff levels for drugs and drug metabolites. (a) Initial drug testing. (1) HHS-certified laboratories shall apply the following cutoff levels for initial...
10 CFR 26.163 - Cutoff levels for drugs and drug metabolites.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Cutoff levels for drugs and drug metabolites. 26.163... the Department of Health and Human Services § 26.163 Cutoff levels for drugs and drug metabolites. (a) Initial drug testing. (1) HHS-certified laboratories shall apply the following cutoff levels for initial...

10 CFR 26.163 - Cutoff levels for drugs and drug metabolites.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false Cutoff levels for drugs and drug metabolites. 26.163... the Department of Health and Human Services § 26.163 Cutoff levels for drugs and drug metabolites. (a) Initial drug testing. (1) HHS-certified laboratories shall apply the following cutoff levels for initial...
10 CFR 26.163 - Cutoff levels for drugs and drug metabolites.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Cutoff levels for drugs and drug metabolites. 26.163... the Department of Health and Human Services § 26.163 Cutoff levels for drugs and drug metabolites. (a) Initial drug testing. (1) HHS-certified laboratories shall apply the following cutoff levels for initial...
40 CFR 53.53 - Test for flow rate accuracy, regulation, measurement accuracy, and cut-off.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., measurement accuracy, and cut-off. 53.53 Section 53.53 Protection of Environment ENVIRONMENTAL PROTECTION..., measurement accuracy, and cut-off. (a) Overview. This test procedure is designed to evaluate a candidate... measurement accuracy, coefficient of variability measurement accuracy, and the flow rate cut-off function. The...
The Effects of Low- and High-Energy Cutoffs on Solar Flare Microwave and Hard X-Ray Spectra

NASA Technical Reports Server (NTRS)

Holman, G. D.; Oegerle, William (Technical Monitor)

2002-01-01

Microwave and hard x-ray spectra provide crucial information about energetic electrons and their environment in solar flares. These spectra are becoming better determined with the Owens Valley Solar Array (OVSA) and the recent launch of the Ramaty High Energy Solar Spectroscopic Imager (RHESSI). The proposed Frequency Agile Solar Radiotelescope (FASR) promises even greater advances in radio observations of solar flares. Both microwave and hard x-ray spectra are sensitive to cutoffs in the electron distribution function. The determination of the high-energy cutoff from these spectra establishes the highest electron energies produced by the acceleration mechanism, while determination of the low-energy cutoff is crucial to establishing the total energy in accelerated electrons. This paper will show computations of the effects of both high- and low-energy cutoffs on microwave and hard x-ray spectra. The optically thick portion of a microwave spectrum is enhanced and smoothed by a low-energy cutoff, while a hard x-ray spectrum is flattened below the cutoff energy. A high-energy cutoff steepens the microwave spectrum and increases the wavelength at which the spectrum peaks, while the hard x-ray spectrum begins to steepen at photon energies roughly an order of magnitude below the electron cutoff energy. This work discusses how flare microwave and hard x-ray spectra can be analyzed together to determine these electron cutoff energies. This work is supported in part by the NASA Sun-Earth Connection Program.
Augmenting groundwater monitoring networks near landfills with slurry cutoff walls.

PubMed

Hudak, Paul F

2004-01-01

This study investigated the use of slurry cutoff walls in conjunction with monitoring wells to detect contaminant releases from a solid waste landfill. The 50 m wide by 75 m long landfill was oriented oblique to regional groundwater flow in a shallow sand aquifer. Computer models calculated flow fields and the detection capability of six monitoring networks, four including a 1 m wide by 50 m long cutoff wall at various positions along the landfill's downgradient boundaries and upgradient of the landfill. Wells were positioned to take advantage of convergent flow induced downgradient of the cutoff walls. A five-well network with no cutoff wall detected 81% of contaminant plumes originating within the landfill's footprint before they reached a buffer zone boundary located 50 m from the landfill's downgradient corner. By comparison, detection efficiencies of networks augmented with cutoff walls ranged from 81 to 100%. The most efficient network detected 100% of contaminant releases with four wells, with a centrally located, downgradient cutoff wall. In general, cutoff walls increased detection efficiency by delaying transport of contaminant plumes to the buffer zone boundary, thereby allowing them to increase in size, and by inducing convergent flow at downgradient areas, thereby funneling contaminant plumes toward monitoring wells. However, increases in detection efficiency were too small to offset construction costs for cutoff walls. A 100% detection efficiency was also attained by an eight-well network with no cutoff wall, at approximately one-third the cost of the most efficient wall-augmented network.
Montreal Cognitive Assessment: One Cutoff Never Fits All.

PubMed

Wong, Adrian; Law, Lorraine S N; Liu, Wenyan; Wang, Zhaolu; Lo, Eugene S K; Lau, Alexander; Wong, Lawrence K S; Mok, Vincent C T

2015-12-01

The objective of this study is to examine the discrepancy between single versus age and education corrected cutoff scores in classifying performance on the Montreal Cognitive Assessment (MoCA) in patients with stroke or transient ischemic attack. MoCA norms were collected from 794 functionally independent and stroke- and dementia-free persons aged ≥65 years. magnetic resonance imaging was used to exclude healthy controls with significant brain pathology and medial temporal lobe atrophy. Cutoff scores at 16th, 7th, and 2nd percentiles by age and education were derived for the MoCA and MoCA 5-minute Protocol. MoCA performance in 919 patients with stroke or transient ischemic attack was classified using the single and norm-derived cutoff scores. The norms for the Hong Kong version of the MoCA total and domain scores and the total score of the MoCA 5-minute protocol are described. Only 65.1% and 25.7% healthy controls and 45.2% and 19.0% patients scored above the conventional cutoff scores of 21/22 and 25/26 on the MoCA. Using classification with norm-derived cutoff scores as reference, locally derived cutoff score of 21/22 yielded a classification discrepancy of ≤42.4%. Discrepancy increased with higher age and lower education level, with the majority being false positives by single cutoffs. With the 25/26 cutoff of the original MoCA, discrepancy further increased to ≤74.3%. Conventional single cutoff scores are associated with substantially high rates of misclassification especially in older and less-educated patients with stroke. These results caution against the use of one-size-fits-all cutoffs on the MoCA. © 2015 American Heart Association, Inc.
Mach Cutoff Analysis and Results from NASA's Farfield Investigation of No-Boom Thresholds

NASA Technical Reports Server (NTRS)

Cliatt, Larry J., II; Hill, Michael A.; Haering, Edward A., Jr.

2016-01-01

In support of the ongoing effort by the National Aeronautics and Space Administration (NASA) to bring supersonic commercial travel to the public, the NASA Armstrong Flight Research Center and the NASA Langley Research Center, in partnership with other industry organizations and academia, conducted a flight research experiment to analyze acoustic propagation in the Mach cutoff shadow zone. The effort was conducted in the fall of 2012 and named the Farfield Investigation of No-boom Thresholds (FaINT). The test helped to build a dataset that will go toward further understanding of the unique acoustic propagation characteristics below Mach cutoff altitude. FaINT was able to correlate sonic boom noise levels measured below cutoff altitude with precise airplane flight conditions, potentially increasing the accuracy over previous studies. A NASA F-18B airplane made supersonic passes such that its Mach cutoff caustic would be at varying distances above a linear 60-microphone, 7375-ft (2247.9 m) long array. A TG-14 motor glider equipped with a microphone on its wing-tip also attempted to capture the same sonic boom waves above ground, but below the Mach cutoff altitude. This paper identified an appropriate metric for sonic boom waveforms in the Mach cutoff shadow zone called Perceived Sound Exposure Level; derived an empirical relationship between Mach cutoff flight conditions and noise levels in the shadow zone; validated a safe cutoff altitude theory presented by previous studies; analyzed the sensitivity of flight below Mach cutoff to unsteady atmospheric conditions and realistic aircraft perturbations; and demonstrated the ability to record sonic boom measurements over 5000 ft (1524.0 m) above ground level, but below Mach cutoff altitude.
[The Dependent Personality Questionnaire (DPQ): French translation and validation study in a population of 138 hospitalized psychiatric patients].

PubMed

Loas, G; Monestes, J-L; Wallier, J; Berthoz, S; Corcos, M

2010-04-01

Dependent personality disorder is a new diagnosis introduced in the third version of the DSM (DSM-III). Contrary to other disorders of personality, as the borderline or the schizotypal personalities, there are no specific interviews or questionnaires focusing on dependent personality. Thus the study of dependent personality disorder requires the use of global interviews or questionnaire as the SCID -II or SIDP-IV. Recently, Tyrer and colleagues (2004) have proposed an 8-item questionnaire, the DPQ (Dependent Personality Questionnaire). Each item of the DPQ is rated from 0 to 3 with a total score ranging from 0 to 24. Using a sample of 30 psychiatric patients presenting various diagnoses and a dependent personality disorder for the half of the sample, the authors have determined the cutoff score allowing the diagnosis of DSM-IV Dependent Personality Disorder. A cutoff of 10 was associated with the best sensitivity (87.5%), specificity (87.5%) and positive predictive value (87.5%). Moreover, the value of the Youden coefficient (Sensitivity+Specificity - 100) was 75. The aim of the study was to present the French version of the DPQ and to determine its psychometric properties as well as the cutoff score. One hundred and thirty-eight psychiatric inpatients (97 females, 41 males) with a mean age of 42.26 years were included in the study. The patients were hospitalized in an inpatients unit receiving mood disorders, neurotic disorders or suicide attempters. The subjects filled out the French versions of the DPQ and the Personality Disorders Questionnaire of Hyler, PDQ-4+. Using the PDQ-4+ two groups were built: 25 subjects filled out the diagnoses of dependent personality disorder and 20 subjects did not meet any criteria of dependent personality disorder. Then, for different values of the DPQ, sensitivity, specificity and positive predictive value and Youden indicia (Sensitivity+Specificity - 100) were calculated. The best values of Youden indicia (74) were obtained for the cutoff of 13 on the DPQ. The corresponding sensitivity, specificity and positive predictive value were respectively 84, 90 and 91.3%. The French version of the DPQ is now available and permits detection of dependent personality in French populations. Our results must be replicated using structured interviews of personality disorder instead of questionnaires (PDQ-4+) and other samples with different prevalence of dependent personality disorders must be used to test the potential cutoff scores of the DPQ. 2009 L'Encéphale, Paris. Published by Elsevier Masson SAS. All rights reserved.
Patient Generated Subjective Global Assessment as a prognosis tool in women with gynecologic cancer.

PubMed

Rodrigues, Camila Santos; Lacerda, Marina Seraphim; Chaves, Gabriela Villaça

2015-01-01

The aim of this study was to assess the nutritional status (NS) of women hospitalized for gynecologic tumors and relate it to such outcomes as hospital length of stay and 1-y mortality. We assessed 146 women diagnosed with gynecologic tumors who were admitted to a referral oncologic hospital in November 2012. Data collected included medical history, duration and reason for admission, and cases of death within 1 y. NS was assessed using Patient-Generated Subjective Global Assessment (PG-SGA). The receiver operating characteristic curve was used to define the best cutoff point for discriminating individuals who did or did not die. We used proportional hazards regression to assess associations between malnutrition and 1-y mortality. According to the PG-SGA, 62.4% of the women were classified as being at nutritional risk or having moderate or severe malnutrition. Sorting patients by stage of cancer, there was no statistical difference in NS classification according to the different cancer sites. The median hospital stay, in days, was statistically lower in patients classified as well nourished. Individuals with a score above the cutoff point of 10 were 30.7 times more likely (95% confidence interval, 11.8-79.4) to die. There was a 52.1% rate of mortality within 1 y. Patients classed as having some degree of malnutrition had a significantly lower median survival rate. A diagnosis of cervical cancer and severe malnourishment increases the likelihood of death. Our findings suggest that the PG-SGA can be considered not just as an indicator of nutritional risk, but also as a major predictor of prognosis and mortality in this population. Copyright © 2015 Elsevier Inc. All rights reserved.
Global Energetics of Solar Flares. Part III; Nonthermal Energies

NASA Technical Reports Server (NTRS)

Aschwanden, Markus J.; Holman, Gordon; O'Flannagain, Aidan; Caspi, Amir; McTiernan, James M.; Kontar, Eduard P.

2016-01-01

This study entails the third part of a global flare energetics project, in which Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) data of 191 M and X-class flare events from the first 3.5 years of the Solar Dynamics Observatory mission are analyzed. We fit a thermal and a nonthermal component to RHESSI spectra, yielding the temperature of the differential emission measure (DEM) tail, the nonthermal power-law slope and flux, and the thermal nonthermal cross-over energy eco. From these parameters, we calculate the total nonthermal energy E(sub nt) in electrons with two different methods: (1) using the observed cross-over energy e(sub co) as low-energy cutoff, and (2) using the low-energy cut off e(sub wt) predicted by the warm thick-target bremsstrahlung model of Kontar et al. Based on a mean temperature of T(sub e) = 8.6 MK in active regions, we find low-energy cutoff energies of e(sub wt) = 6.2 +/-1.6 keV for the warm-target model, which is significantly lower than the cross-over energies e(sub co) = 21 +/- 6 keV. Comparing with the statistics of magnetically dissipated energies E(sub mag) and thermal energies E(sub th) from the two previous studies, we find the following mean (logarithmic) energy ratios with the warm-target model: E(sub nt) = 0.41E(sub mag), E(sub th) = 0.08 E(sub mag), and E(sub th) = 0.15 E(sub nt). The total dissipated magnetic energy exceeds the thermal energy in 95% and the nonthermal energy in 71% of the flare events, which confirms that magnetic reconnection processes are sufficient to explain flare energies. The nonthermal energy exceeds the thermal energy in 85% of the events, which largely confirms the warm thick-target model.
Inappropriate Use of Homeostasis Model Assessment Cutoff Values for Diagnosing Insulin Resistance in Pediatric Studies.

PubMed

Fox, Carrie; Bernardino, Lourdes; Cochran, Jill; Essig, Mary; Bridges, Kristie Grove

2017-11-01

Assessing pediatric patients for insulin resistance is one way to identify those who are at a high risk of developing type 2 diabetes mellitus. The homoeostasis model assessment (HOMA) is a measure of insulin resistance based on fasting blood glucose and insulin levels. Although this measure is widely used in research, cutoff values for pediatric populations have not been established. To assess the validity of HOMA cutoff values used in pediatric studies published in peer-reviewed journals. Studies published from January 2010 to December 2015 were identified through MEDLINE. Initial screening of abstracts was done to select studies that were conducted in pediatric populations and used HOMA to assess insulin resistance. Subsequent full-text review narrowed the list to only those studies that used a specific HOMA score to diagnose insulin resistance. Each study was classified as using a predetermined fixed HOMA cutoff value or a cutoff that was a percentile specific to that population. For studies that used a predetermined cutoff value, the references cited to provide evidence in support of that cutoff were evaluated. In the 298 articles analyzed, 51 different HOMA cutoff values were used to classify patients as having insulin resistance. Two hundred fifty-five studies (85.6%) used a predetermined fixed cutoff value, but only 72 (28.2%) of those studies provided a reference that supported its use. One hundred ten studies (43%) that used a fixed cutoff either cited a study that did not mention HOMA or provided no reference at all. Tracing of citation history indicated that the most commonly used cutoff values were ultimately based on studies that did not validate their use for defining insulin resistance. Little evidence exists to support HOMA cutoff values commonly used to define insulin resistance in pediatric studies. These findings highlight the importance of validating study design elements when training medical students and novice investigators. Using available data to generate population ranges for HOMA would improve its clinical utility.
Optimized classification of 18F-Florbetaben PET scans as positive and negative using an SUVR quantitative approach and comparison to visual assessment.

PubMed

Bullich, Santiago; Seibyl, John; Catafau, Ana M; Jovalekic, Aleksandar; Koglin, Norman; Barthel, Henryk; Sabri, Osama; De Santi, Susan

2017-01-01

Standardized uptake value ratios (SUVRs) calculated from cerebral cortical areas can be used to categorize 18 F-Florbetaben (FBB) PET scans by applying appropriate cutoffs. The objective of this work was first to generate FBB SUVR cutoffs using visual assessment (VA) as standard of truth (SoT) for a number of reference regions (RR) (cerebellar gray matter (GCER), whole cerebellum (WCER), pons (PONS), and subcortical white matter (SWM)). Secondly, to validate the FBB PET scan categorization performed by SUVR cutoffs against the categorization made by post-mortem histopathological confirmation of the Aβ presence. Finally, to evaluate the added value of SUVR cutoff categorization to VA. SUVR cutoffs were generated for each RR using FBB scans from 143 subjects who were visually assessed by 3 readers. SUVR cutoffs were validated in 78 end-of life subjects using VA from 8 independent blinded readers (3 expert readers and 5 non-expert readers) and histopathological confirmation of the presence of neuritic beta-amyloid plaques as SoT. Finally, the number of correctly or incorrectly classified scans according to pathology results using VA and SUVR cutoffs was compared. Composite SUVR cutoffs generated were 1.43 (GCER), 0.96 (WCER), 0.78 (PONS) and 0.71 (SWM). Accuracy values were high and consistent across RR (range 83-94% for histopathology, and 85-94% for VA). SUVR cutoff performed similarly as VA but did not improve VA classification of FBB scans read either by expert readers or the majority read but provided higher accuracy than some non-expert readers. The accurate scan classification obtained in this study supports the use of VA as SoT to generate site-specific SUVR cutoffs. For an elderly end of life population, VA and SUVR cutoff categorization perform similarly in classifying FBB scans as Aβ-positive or Aβ-negative. These results emphasize the additional contribution that SUVR cutoff classification may have compared with VA performed by non-expert readers.
Young Athletes Cleared for Sports Participation After Anterior Cruciate Ligament Reconstruction: How Many Actually Meet Recommended Return-to-Sport Criterion Cutoffs?

PubMed

Toole, Allison R; Ithurburn, Matthew P; Rauh, Mitchell J; Hewett, Timothy E; Paterno, Mark V; Schmitt, Laura C

2017-11-01

Study Design Prospective cohort study. Background While meeting objective criterion cutoffs is recommended prior to return to sports following anterior cruciate ligament (ACL) reconstruction, the number of young athletes who meet recommended cutoffs and the impact of cutoffs on longitudinal sports participation are unknown. Objectives To test the hypothesis that a higher proportion of young athletes who meet recommended cutoffs will maintain the same level of sports participation over the year following return-to-sport clearance compared to those who do not meet recommended cutoffs. Methods At the time of return-to-sport clearance, the International Knee Documentation Committee Subjective Knee Evaluation Form (IKDC), quadriceps and hamstring strength limb symmetry index (LSI), and single-leg hop test LSI were assessed. Proportions of participants who met individual (IKDC score of 90 or greater; strength and hop test LSIs of 90% or greater) and combined cutoffs were calculated. Proportions of participants who continued at the same level of sports participation over the year following return-to-sport clearance (assessed using the Tegner activity scale) were compared between those who met and did not meet cutoffs. Results Participants included 115 young athletes (88 female). The proportions meeting individual cutoffs ranged from 43.5% to 78.3%. The proportions meeting cutoffs for all hop tests, all strength tests, and all combined measures were 53.0%, 27.8%, and 13.9%, respectively. A higher proportion of participants who met cutoffs for both strength tests maintained the same level of sports participation over the year following return-to-sport clearance than those who did not (81.3% versus 60.2%, P = .02). Conclusion The proportions of young athletes after ACL reconstruction recently cleared for return to sports who met the combined criterion cutoffs were low. Those who met the criterion cutoffs for both strength tests maintained the same level of sports participation at higher proportions than those who did not. Level of Evidence Prognosis, level 2b. J Orthop Sports Phys Ther 2017;47(11):825-833. Epub 7 Oct 2017. doi:10.2519/jospt.2017.7227.
Charged rotating black holes in Einstein-Maxwell-Chern-Simons theory with a negative cosmological constant

NASA Astrophysics Data System (ADS)

Blázquez-Salcedo, Jose Luis; Kunz, Jutta; Navarro-Lérida, Francisco; Radu, Eugen

2017-03-01

We consider rotating black hole solutions in five-dimensional Einstein-Maxwell-Chern-Simons theory with a negative cosmological constant and a generic value of the Chern-Simons coupling constant λ . Using both analytical and numerical techniques, we focus on cohomogeneity-1 configurations, with two equal-magnitude angular momenta, which approach at infinity a globally anti-de Sitter background. We find that the generic solutions share a number of basic properties with the known Cvetič, Lü, and Pope black holes which have λ =1 . New features occur as well; for example, when the Chern-Simons coupling constant exceeds a critical value, the solutions are no longer uniquely determined by their global charges. Moreover, the black holes possess radial excitations which can be labelled by the node number of the magnetic gauge potential function. Solutions with small values of λ possess other distinct features. For instance, the extremal black holes there form two disconnected branches, while not all near-horizon solutions are associated with global solutions.
Hosting a Fourier Transform Spectrometer (FTS) on CubeSat Spacecraft Platforms for Global Measurements of Three-Dimensional Winds

NASA Astrophysics Data System (ADS)

Scott, D. K.; Neilsen, T. L.; Weston, C.; Frazier, C.; Smith, T.; Shumway, A.

2015-12-01

Global measurements of vertically-resolved atmospheric wind profiles offer the potential for improved weather forecasts and superior predictions of atmospheric wind patterns. A small-satellite constellation that uses a Fourier Transform Spectrometer (FTS) instrument onboard 12U CubeSats can provide measurements of global tropospheric wind profiles from space at a very low cost. These small satellites are called FTS CubeSats. This presentation will describe a spacecraft concept that provides a stable, robust platform to host the FTS payload. Of importance to the payload are power, data, station keeping, thermal, and accommodations that enable high spectral measurements to be made from a LEO orbit. The spacecraft concept draws on Space Dynamics Laboratory (SDL) heritage and the recent success of the Dynamic Ionosphere Cubesat Experiment (DICE) and HyperAngular Rainbow Polarimeter (HARP) missions. Working with team members, SDL built a prototype observatory (spacecraft and payload) for testing and proof of concept.
Nucleon-deuteron scattering with the JISP16 potential

NASA Astrophysics Data System (ADS)

Skibiński, R.; Golak, J.; Topolnicki, K.; Witała, H.; Volkotrub, Yu.; Kamada, H.; Shirokov, A. M.; Okamoto, R.; Suzuki, K.; Vary, J. P.

2018-01-01

The nucleon-nucleon J -matrix inverse scattering potential JISP16 is applied to elastic nucleon-deuteron scattering and the deuteron breakup process at the laboratory nucleon energies up to 135 MeV. The formalism of the Faddeev equations is used to obtain three-nucleon scattering states. We compare predictions based on the JISP16 force with data and with results based on various two-body interactions, including the CD Bonn, the Argonne AV18, the chiral force with the semilocal regularization at the fifth order of the chiral expansion and with low-momentum interactions obtained from the CD Bonn force as well as with the predictions from the combination of the AV18 NN interaction and the Urbana IX 3 N force. JISP16 provides a satisfactory description of some observables at low energies but strong deviations from data as well as from standard and chiral potential predictions with increasing energy. However, there are also polarization observables at low energies for which the JISP16 predictions differ from those based on the other forces by a factor of two. The reason for such a behavior can be traced back to the P -wave components of the JISP16 force. At higher energies the deviations can be enhanced by an interference with higher partial waves and by the properties of the JISP16 deuteron wave function. In addition, we compare the energy and angular dependence of predictions based on the JISP16 force with the results of the low-momentum interactions obtained with different values of the momentum cutoff parameter. We found that such low-momentum forces can be employed to interpret the nucleon-deuteron elastic scattering data only below some specific energy which depends on the cutoff parameter. Since JISP16 is defined in a finite oscillator basis, it has properties similar to low momentum interactions and its application to the description of nucleon-deuteron scattering data is limited to a low momentum transfer region.
CASCADE AND DAMPING OF ALFVEN-CYCLOTRON FLUCTUATIONS: APPLICATION TO SOLAR WIND TURBULENCE

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

Jiang Yanwei; Petrosian, Vahe; Liu Siming

2009-06-10

It is well recognized that the presence of magnetic fields will lead to anisotropic energy cascade and dissipation of astrophysical turbulence. With the diffusion approximation and linear dissipation rates, we study the cascade and damping of Alfven-cyclotron fluctuations in solar plasmas numerically for two diagonal diffusion tensors, one (isotropic) with identical components for the parallel and perpendicular directions (with respect to the magnetic field) and one with different components (nonisotropic). It is found that for the isotropic case the steady-state turbulence spectra are nearly isotropic in the inertial range and can be fitted by a single power-law function with amore » spectral index of -3/2, similar to the Iroshnikov-Kraichnan phenomenology, while for the nonisotropic case the spectra vary greatly with the direction of propagation. The energy fluxes in both cases are much higher in the perpendicular direction than in the parallel direction due to the angular dependence (or inhomogeneity) of the components. In addition, beyond the MHD regime the kinetic effects make the spectrum softer at higher wavenumbers. In the dissipation range the turbulence spectrum cuts off at the wavenumber, where the damping rate becomes comparable to the cascade rate, and the cutoff wavenumber changes with the wave propagation direction. The angle-averaged turbulence spectrum of the isotropic model resembles a broken power law, which cuts off at the maximum of the cutoff wavenumbers or the {sup 4}He cyclotron frequency. Taking into account the Doppler effects, the model naturally reproduces the broken power-law turbulence spectra observed in the solar wind and predicts that a higher break frequency always comes along with a softer dissipation range spectrum that may be caused by the increase of the turbulence intensity, the reciprocal of the plasma {beta}{sub p}, and/or the angle between the solar wind velocity and the mean magnetic field. These predictions can be tested by detailed comparisons with more accurate observations.« less
Isotretinoin was not associated with depression or anxiety: A twelve-week study

PubMed Central

Suarez, Bella; Serrano, Ana; Cova, Yves; Baptista, Trino

2016-01-01

AIM: To investigate the frequency and severity of depression and/or anxiety in isotretinoin (ITT)-treated subjects and in a non-ITT control group. METHODS: Sixty consecutively-admitted non-psychiatric outpatients with acne were assigned to either ITT at a fixed dose of 30 mg/d (n = 36) or “other treatment” group (OT; n = 24). The Zung depression or anxiety scales (with cut-off points), two locally developed scales for depression (GeDepr) and anxiety (Ansilet) (without cut-off points) and clinical global impression scales of acne severity were administered at baseline and at weeks 6 and 12 of treatment. Data was analyzed with the chi-squared test and covariance analysis. RESULTS: Gender distribution, age, marital status and education level did not differ between both treatment groups. The frequency of depression, as defined by the Zung scale cut-off points was similar in the ITT and in the non-ITT groups: Weeks 6 and 12: 8.3% in both groups, P = 0.9. The frequency of anxiety was similar in the groups as well: Week 6: ITT = 8.3%; OT = 0.0%, P > 0.05; week 12: ITT = 11.1%, OT = 4.2%, P > 0.05. The scores in both scales’ sets did not differ between the treatment groups at any evaluation time point (P > 0.05). Five ITT-treated subjects (13.8%) and two from the OT-treated group (8.3%) developed clinically significant anxiety and/or depression during treatment (P > 0.05). CONCLUSION: Our study confirms the safety of ITT regarding psychological side effects in regular dermatological patients. Susceptible subjects may exist but their identification requires additional strategies. PMID:27014604
Mitral annulus motion as determined by M-mode echocardiography in normal dogs and dogs with cardiac disease.

PubMed

Schober, K E; Fuentes, V L

2001-01-01

M-mode echocardiography was used to assess apical mitral annulus motion (MAM) in 103 normal dogs and 101 dogs with cardiac disease, to obtain information on systolic left ventricular long axis function. In normal dogs, a close relationship was found between MAM and body weight (r = 0.80, P < 0.001). There was a weak correlation between MAM and heart rate (r = -0.25, P < 0.05), but no correlation between MAM and age or left ventricular shortening fraction (P > 0.05). Mean MAM (95% confidence intervals) were established for normal dogs of differing body weight, and were 0.70 cm (0.65 to 0.75) in dogs < 15 kg, 1.08 cm (1.03 to 1.13) in dogs weighing 15 to 40 kg, and 1.51 cm (1.21 to 1.81) in dogs > 40 kg. "Cut-off" values to define decreased MAM for normal dogs of differing body weight were 0.45 cm (dogs < 15 kg), 0.80 cm (dogs 15-40 kg), and 1.20 cm (dogs > 40 kg). In dogs with cardiac disease, median MAM was normal in mitral valve endocardiosis or aortic stenosis, but significantly decreased (P < 0.05) in dilated cardiomyopathy. All dogs with mitral valve endocardiosis (n = 54) or aortic stenosis (n = 26) had MAM above the above-mentioned "cut-off" values, suggesting normal or increased left ventricular longitudinal systolic shortening, whereas 81% (17/21) of dogs with dilated cardiomyopathy had MAM below the "cut-off" value, indicating decreased long axis systolic function. It is concluded that MAM may be used to evaluate systolic left ventricular long axis performance in dogs and may add useful information on global left ventricular contraction dynamics.
Spanish version of the Mattis Dementia Rating Scale-2 for early detection of Alzheimer's disease and mild cognitive impairment.

PubMed

Boycheva, Elina; Contador, Israel; Fernández-Calvo, Bernardino; Ramos-Campos, Francisco; Puertas-Martín, Verónica; Villarejo-Galende, Alberto; Bermejo-Pareja, Félix

2018-06-01

We aimed to analyse the clinical utility of the Mattis Dementia Rating Scale (MDRS-2) for early detection of Alzheimer's disease (AD) and amnestic mild cognitive impairment (MCI) in a sample of Spanish older adults. A total of 125 participants (age = 75.12 ± 6.83, years of education =7.08 ± 3.57) were classified in three diagnostic groups: 45 patients with mild AD, 37 with amnestic MCI-single and multiple domain and 43 cognitively healthy controls (HCs). Reliability, criterion validity and diagnostic accuracy of the MDRS-2 (total and subscales) were analysed. The MDRS-2 scores, adjusted by socio-demographic characteristics, were calculated through hierarchical multiple regression analysis. The global scale had adequate reliability (α = 0.736) and good criterion validity (r = 0.760, p < .001) with the Mini-Mental State Examination. The optimal cut-off point between AD patients and HCs was 124 (sensitivity [Se] = 97% and specificity [Sp] = 95%), whereas 131 (Se = 89%, Sp = 81%) was the optimal cut-off point between MCI and HCs. An optimal cut-off point of 123 had good Se (0.97), but poor Sp (0.56) to differentiate AD and MCI groups. The Memory and Initiation/Perseveration subscales had the highest discriminative capacity between the groups. The MDRS-2 is a reliable and valid instrument for the assessment of cognitive impairment in Spanish older adults. In particular, optimal capacity emerged for the detection of early AD and MCI. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Predictive value of early brain atrophy on response in patients treated with interferon β

PubMed Central

Pérez-Miralles, Francisco Carlos; Vidal-Jordana, Angela; Río, Jordi; Auger, Cristina; Pareto, Deborah; Tintoré, Mar; Rovira, Alex; Montalban, Xavier

2015-01-01

Objective: To investigate the association between brain volume loss during the first year of interferon treatment and clinical outcome at 4 years. Methods: Patients with multiple sclerosis initiating interferon β were clinically evaluated every 6 months for the presence of relapses and assessment of global disability using the Expanded Disability Status Scale (EDSS). MRI scans were performed at baseline and after 12 months, and the percentage of brain volume change (PBVC), brain parenchymal volume change (BPVc%), gray matter volume change (GMVc%), and white matter volume change (WMVc%) were estimated. Patients were divided based on the cutoff values for predicting confirmed EDSS worsening obtained by receiver operating characteristic analysis for all atrophy measurements. Survival curves and Cox proportional hazards regression to predict disability worsening at last observation were applied, adjusting for demographic, clinical, and radiologic variables. Results: Larger PBVC and WMVc% decreases were observed in patients with disability worsening at 4 years of follow-up, whereas no differences were found in BPVc% or GMVc%. Cutoff points were obtained for PBVC (−0.86%; sensitivity 65.5%, specificity 71.4%) and WMVc% (−2.49%; sensitivity 85.3%, specificity 43.8%). Patients with decreases of PBVC and WMVc% below cutoff values were more prone to develop disability worsening (unadjusted hazard ratio [HR] 3.875, p = 0.005; HR 4.246, p = 0.004, respectively). PBVC (HR 4.751, p = 0.008) and the interaction of new T2 lesions with WMVc% (HR 1.086, p = 0.005) were found to be independent predictors of disability worsening in the multivariate analysis. Conclusions: At the patient level, whole-brain and white matter volume changes in the first year of interferon β therapy are predictive of subsequent clinical evolution under treatment. PMID:26185778
Predictive value of early brain atrophy on response in patients treated with interferon β.

PubMed

Pérez-Miralles, Francisco Carlos; Sastre-Garriga, Jaume; Vidal-Jordana, Angela; Río, Jordi; Auger, Cristina; Pareto, Deborah; Tintoré, Mar; Rovira, Alex; Montalban, Xavier

2015-08-01

To investigate the association between brain volume loss during the first year of interferon treatment and clinical outcome at 4 years. Patients with multiple sclerosis initiating interferon β were clinically evaluated every 6 months for the presence of relapses and assessment of global disability using the Expanded Disability Status Scale (EDSS). MRI scans were performed at baseline and after 12 months, and the percentage of brain volume change (PBVC), brain parenchymal volume change (BPVc%), gray matter volume change (GMVc%), and white matter volume change (WMVc%) were estimated. Patients were divided based on the cutoff values for predicting confirmed EDSS worsening obtained by receiver operating characteristic analysis for all atrophy measurements. Survival curves and Cox proportional hazards regression to predict disability worsening at last observation were applied, adjusting for demographic, clinical, and radiologic variables. Larger PBVC and WMVc% decreases were observed in patients with disability worsening at 4 years of follow-up, whereas no differences were found in BPVc% or GMVc%. Cutoff points were obtained for PBVC (-0.86%; sensitivity 65.5%, specificity 71.4%) and WMVc% (-2.49%; sensitivity 85.3%, specificity 43.8%). Patients with decreases of PBVC and WMVc% below cutoff values were more prone to develop disability worsening (unadjusted hazard ratio [HR] 3.875, p = 0.005; HR 4.246, p = 0.004, respectively). PBVC (HR 4.751, p = 0.008) and the interaction of new T2 lesions with WMVc% (HR 1.086, p = 0.005) were found to be independent predictors of disability worsening in the multivariate analysis. At the patient level, whole-brain and white matter volume changes in the first year of interferon β therapy are predictive of subsequent clinical evolution under treatment.
Development of norms for executive functions in typically-developing Indian urban preschool children and its association with nutritional status.

PubMed

Selvam, Sumithra; Thomas, Tinku; Shetty, Priya; Thennarasu, K; Raman, Vijaya; Khanna, Deepti; Mehra, Ruchika; Kurpad, Anura V; Srinivasan, Krishnamachari

2018-02-01

Executive functions (EFs) are essential and important for achieving success in children's everyday lives and play a fundamental role in children's cognitive, academic, social, emotional and behavioral functioning. A cross-sectional study was carried out to develop age- and sex-specific norms for EFs using the Behavior Rating Inventory of Executive Function - Preschool Version (BRIEF-P) among 2- to 5-year-olds from urban Bangalore, India. In addition, the association between EFs and anthropometric measures, a marker of nutritional status, is also examined. Primary caregivers of 412 children, equally distributed by age and sex, participated. Raw scores for each domain and indices were converted to standard t-scores and percentiles were computed. A t-score at or above 63 corresponding to the 90th percentile was considered as the cutoff for executive dysfunction in this sample. The prevalence of executive dysfunction is 10% based on the Global Executive Composite score of the BRIEF-P. The cutoff score for identifying executive dysfunction using existing United States (US) norms is higher compared to the cutoff score obtained in the current study. Therefore, using US norms for Indian children could result in the prevalence of executive dysfunction been underestimated. Multiple linear regression analysis revealed that stunted and underweight children have significantly elevated EF scores after adjusting for age, sex and socioeconomic status (SES; p < .01). A greater understanding of EFs in preschool children is important for the early identification of executive dysfunction and implementing interventions to improve their future prospects. This study also shows that undernourished children are more likely to have executive dysfunction.
Global emergency medicine journal club: a social media discussion about the Age-Adjusted D-Dimer Cutoff Levels To Rule Out Pulmonary Embolism trial.

PubMed

Rezaie, Salim R; Swaminathan, Anand; Chan, Teresa; Shaikh, Sam; Lin, Michelle

2015-05-01

Annals of Emergency Medicine collaborated with an educational Web site, Academic Life in Emergency Medicine (ALiEM), to host an online discussion session featuring the 2014 Journal of the American Medical Association publication on the Age-Adjusted D-Dimer Cutoff Levels to Rule Out Pulmonary Embolism (ADJUST-PE) trial by Righini et al. The objective is to describe a 14-day (August 25 to September 7, 2014) worldwide academic dialogue among clinicians in regard to 4 preselected questions about the age-adjusted D-dimer cutoff to detect pulmonary embolism. Five online facilitators hosted the multimodal discussion on the ALiEM Web site, Twitter, and Google Hangout. Comments across the social media platforms were curated for this report, as framed by the 4 preselected questions, and engagement was tracked through various Web analytic tools. Blog and Twitter comments, as well as video expert commentary involving the ADJUST-PE trial, are summarized. The dialogue resulted in 1,169 page views from 391 cities in 52 countries on the ALiEM Web site, 502,485 Twitter impressions, and 159 views of the video interview with experts. A postdiscussion summary on the Journal Jam podcast resulted in 3,962 downloads in its first week of publication during September 16 to 23, 2014. Common themes that arose in the multimodal discussions included the heterogeneity of practices, D-dimer assays, provider knowledge about these assays, and prevalence rates in different areas of the world. This educational approach using social media technologies demonstrates a free, asynchronous means to engage a worldwide audience in scholarly discourse. Copyright © 2015 American College of Emergency Physicians. Published by Elsevier Inc. All rights reserved.
Good and poor sleepers among OSA patients: sleep quality and overnight polysomnography findings.

PubMed

Lusic Kalcina, Linda; Valic, Maja; Pecotic, Renata; Pavlinac Dodig, Ivana; Dogas, Zoran

2017-07-01

Previous studies aimed to determine if Pittsburgh sleep quality index (PSQI) is a valid screening instrument for obstructive sleep apnea, indicating its disadvantages. However, the rationale of PSQI use in sleep clinics is not the screening, but the assessment of sleep quality itself. Therefore, the aims of this study were to investigate the sleep quality in obstructive sleep apnea patients and to identify the cutoff point for differentiation of "good" and "poor" sleepers among them. We constructed the Croatian version of PSQI and assessed its psychometric properties. The protocol of the study included the assessment of sleep quality in 130 obstructive sleep apnea patients and 75 healthy control subjects. All subjects completed the Croatian version of the PSQI, and the patients underwent overnight polysomnography screening. Obstructive sleep apnea patients had higher values of the global PSQI component score, indicating lower sleep quality, compared to a healthy control group (p < 0.001). The psychometric properties of PSQI scores in the prediction of normal sleep efficiency indicate that the cutoff score of 9.5 differentiates patients in total sleep time (p < 0.001), REM duration (p = 0.014), sleep efficiency (p = 0.001), time spent awake during sleep (p = 0.006), after sleep (p = 0.024), and after sleep onset (p = 0.001). In OSA patients, a PSQI cutoff score of 9.5 differentiated good and poor sleepers significantly in total sleep time, REM duration, time spent awake during sleep, and WASO time. Current findings enhance the interpretability of PSQI results in a population of OSA patients.
10 CFR 26.133 - Cutoff levels for drugs and drug metabolites.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false Cutoff levels for drugs and drug metabolites. 26.133... § 26.133 Cutoff levels for drugs and drug metabolites. Subject to the provisions of § 26.31(d)(3)(iii), licensees and other entities may specify more stringent cutoff levels for drugs and drug metabolites than...
10 CFR 26.133 - Cutoff levels for drugs and drug metabolites.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Cutoff levels for drugs and drug metabolites. 26.133... § 26.133 Cutoff levels for drugs and drug metabolites. Subject to the provisions of § 26.31(d)(3)(iii), licensees and other entities may specify more stringent cutoff levels for drugs and drug metabolites than...
10 CFR 26.133 - Cutoff levels for drugs and drug metabolites.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false Cutoff levels for drugs and drug metabolites. 26.133... § 26.133 Cutoff levels for drugs and drug metabolites. Subject to the provisions of § 26.31(d)(3)(iii), licensees and other entities may specify more stringent cutoff levels for drugs and drug metabolites than...
49 CFR 40.87 - What are the cutoff concentrations for drug tests?

Code of Federal Regulations, 2010 CFR

2010-10-01

... TRANSPORTATION WORKPLACE DRUG AND ALCOHOL TESTING PROGRAMS Drug Testing Laboratories § 40.87 What are the cutoff concentrations for drug tests? (a) As a laboratory, you must use the cutoff concentrations displayed in the... 49 Transportation 1 2010-10-01 2010-10-01 false What are the cutoff concentrations for drug tests...
49 CFR 40.87 - What are the cutoff concentrations for drug tests?

Code of Federal Regulations, 2014 CFR

2014-10-01

... TRANSPORTATION WORKPLACE DRUG AND ALCOHOL TESTING PROGRAMS Drug Testing Laboratories § 40.87 What are the cutoff concentrations for drug tests? (a) As a laboratory, you must use the cutoff concentrations displayed in the... 49 Transportation 1 2014-10-01 2014-10-01 false What are the cutoff concentrations for drug tests...
49 CFR 40.87 - What are the cutoff concentrations for drug tests?

Code of Federal Regulations, 2013 CFR

2013-10-01

... TRANSPORTATION WORKPLACE DRUG AND ALCOHOL TESTING PROGRAMS Drug Testing Laboratories § 40.87 What are the cutoff concentrations for drug tests? (a) As a laboratory, you must use the cutoff concentrations displayed in the... 49 Transportation 1 2013-10-01 2013-10-01 false What are the cutoff concentrations for drug tests...
49 CFR 40.87 - What are the cutoff concentrations for drug tests?

Code of Federal Regulations, 2012 CFR

2012-10-01

... TRANSPORTATION WORKPLACE DRUG AND ALCOHOL TESTING PROGRAMS Drug Testing Laboratories § 40.87 What are the cutoff concentrations for drug tests? (a) As a laboratory, you must use the cutoff concentrations displayed in the... 49 Transportation 1 2012-10-01 2012-10-01 false What are the cutoff concentrations for drug tests...
49 CFR 40.87 - What are the cutoff concentrations for drug tests?

Code of Federal Regulations, 2011 CFR

2011-10-01

... TRANSPORTATION WORKPLACE DRUG AND ALCOHOL TESTING PROGRAMS Drug Testing Laboratories § 40.87 What are the cutoff concentrations for drug tests? (a) As a laboratory, you must use the cutoff concentrations displayed in the... 49 Transportation 1 2011-10-01 2011-10-01 false What are the cutoff concentrations for drug tests...
A severe artifact in simulation of liquid water using a long cut-off length: Appearance of a strange layer structure

NASA Astrophysics Data System (ADS)

Yonetani, Yoshiteru

2005-04-01

We report that a severe artifact appeared in molecular dynamics simulation of bulk water using the long cut-off length 18 Å. Our result shows that increasing the cut-off length does not always improve the simulation result. Moreover, the use of the long cut-off length can lead to a spurious result. It is suggested that the simulation of solvated biomolecules using such a long cut-off length, which has been often performed, may contain an unexpected artifact.
Effect of cutoff radius, long range interaction and temperature controller on thermodynamic properties of fluids: Methanol as an example

NASA Astrophysics Data System (ADS)

Obeidat, Abdalla; Jaradat, Adnan; Hamdan, Bushra; Abu-Ghazleh, Hind

2018-04-01

The best spherical cutoff radius, long range interaction and temperature controller were determined using surface tension, density, and diffusion coefficients of van Leeuwen and Smit methanol. A quite good range of cutoff radii from 0.75 to 1.45 nm has been studied on Coulomb cut-off and particle mesh Ewald (PME) long range interaction to determine the best cutoff radius and best long range interaction as well for four sets of temperature: 200, 230, 270 and 300 K. To determine the best temperature controller, the cutoff radius of 1.25 nm was fixed using PME long range interaction on calculating the above properties at low temperature range: 200-300 K.
Optimum wall impedance for spinning modes: A correlation with mode cut-off ratio

NASA Technical Reports Server (NTRS)

Rice, E. J.

1978-01-01

A correlating equation relating the optimum acoustic impedance for the wall lining of a circular duct to the acoustic mode cut-off ratio, is presented. The optimum impedance was correlated with cut-off ratio because the cut-off ratio appears to be the fundamental parameter governing the propagation of sound in the duct. Modes with similar cut-off ratios respond in a similar way to the acoustic liner. The correlation is a semi-empirical expression developed from an empirical modification of an equation originally derived from sound propagation theory in a thin boundary layer. This correlating equation represents a part of a simplified liner design method, based upon modal cut-off ratio, for multimodal noise propagation.
Downscaling ocean conditions with application to the Gulf of Maine, Scotian Shelf and adjacent deep ocean

NASA Astrophysics Data System (ADS)

Katavouta, Anna; Thompson, Keith

2017-04-01

A high resolution regional model (1/36 degree) of the Gulf of Maine, Scotian Shelf and adjacent deep ocean (GoMSS) is developed to downscale ocean conditions from an existing global operational system. First, predictions from the regional GoMSS model in a one-way nesting set up are evaluated using observations from multiple sources including satellite-borne sensors of surface temperature and sea level, CTDs, Argo floats and moored current meters. It is shown that on the shelf, the regional model predicts more realistic fields than the global system because it has higher resolution and includes tides that are absent from the global system. However, in deep water the regional model misplaces deep ocean eddies and meanders associated with the Gulf Stream. This is because of unrealistic internally generated variability (associated with the one-way nesting set up) that leads to decoupling of the regional model from the global system in the deep water. To overcome this problem, the large scales (length scales > 90 km) of the regional model are spectrally nudged towards the global system fields. This leads to more realistic predictions off the shelf. Wavenumber spectra show that even though spectral nudging constrains the large scales, it does not suppress the variability on small scales; on the contrary, it favours the formation of eddies with length scales below the cut-off wavelength of the spectral nudging.
Earth System Dynamics: The Determination and Interpretation of the Global Angular Momentum Budget using the Earth Observing System. Revised

NASA Technical Reports Server (NTRS)

2003-01-01

The objective of this investigation has been to examine the mass and momentum exchange between the atmosphere, oceans, solid Earth, hydrosphere, and cryosphere. The investigation has focused on changes in the Earth's gravity field, its rotation rate, atmospheric and oceanic circulation, global sea level change, ice sheet change, and global ground water circulation observed by contemporary sensors and models. The primary component of the mass exchange is water. The geodetic observables provided by these satellite sensors are used to study the transport of water mass in the hydrological cycle from one component of the Earth to another, and they are also used to evaluate the accuracy of models. As such, the investigation is concerned with the overall global water cycle. This report provides a description of scientific, educational and programmatic activities conducted during the period July 1, 1999 through June 30,2000. Research has continued into measurements of time-varying gravity and its relationship to Earth rotation. Variability of angular momentum and the related excitation of polar motion and Earth rotation have been examined for the atmosphere and oceans at time-scales of weeks to several years. To assess the performance of hydrologic models, we have compared geodetic signals derived from them with those observed by satellites. One key component is the interannual mass variability of the oceans obtained by direct observations from altimetry after removing steric signals. Further studies have been conducted on the steric model to quantify its accuracy at global and basin-scales. The results suggest a significant loss of water mass from the Oceans to the land on time-scales longer than 1-year. These signals are not reproduced in any of the models, which have poorly determined interannual fresh water fluxes. Output from a coupled atmosphere-ocean model testing long-term climate change hypotheses has been compared to simulated errors from the Gravity Recovery and Climate Experiment (GRACE) mission. Results indicate that GRACE will be able to observe seasonal signals at half-wavelengths ranging from 1000 to 10000 km, and may be able to observe secular trends at half- wavelengths of greater than 2000-3000 km for soil moisture and snow depth if they are as large as some of the climate experiments predict.
On Inertial Body Tracking in the Presence of Model Calibration Errors

PubMed Central

Miezal, Markus; Taetz, Bertram; Bleser, Gabriele

2016-01-01

In inertial body tracking, the human body is commonly represented as a biomechanical model consisting of rigid segments with known lengths and connecting joints. The model state is then estimated via sensor fusion methods based on data from attached inertial measurement units (IMUs). This requires the relative poses of the IMUs w.r.t. the segments—the IMU-to-segment calibrations, subsequently called I2S calibrations—to be known. Since calibration methods based on static poses, movements and manual measurements are still the most widely used, potentially large human-induced calibration errors have to be expected. This work compares three newly developed/adapted extended Kalman filter (EKF) and optimization-based sensor fusion methods with an existing EKF-based method w.r.t. their segment orientation estimation accuracy in the presence of model calibration errors with and without using magnetometer information. While the existing EKF-based method uses a segment-centered kinematic chain biomechanical model and a constant angular acceleration motion model, the newly developed/adapted methods are all based on a free segments model, where each segment is represented with six degrees of freedom in the global frame. Moreover, these methods differ in the assumed motion model (constant angular acceleration, constant angular velocity, inertial data as control input), the state representation (segment-centered, IMU-centered) and the estimation method (EKF, sliding window optimization). In addition to the free segments representation, the optimization-based method also represents each IMU with six degrees of freedom in the global frame. In the evaluation on simulated and real data from a three segment model (an arm), the optimization-based method showed the smallest mean errors, standard deviations and maximum errors throughout all tests. It also showed the lowest dependency on magnetometer information and motion agility. Moreover, it was insensitive w.r.t. I2S position and segment length errors in the tested ranges. Errors in the I2S orientations were, however, linearly propagated into the estimated segment orientations. In the absence of magnetic disturbances, severe model calibration errors and fast motion changes, the newly developed IMU centered EKF-based method yielded comparable results with lower computational complexity. PMID:27455266
[Personalizing the reference level: gold standard to evaluate the quality of service perceived].

PubMed

Rodrigo-Rincón, I; Reyes-Pérez, M; Martínez-Lozano, M E

2014-01-01

To know the cutoff point at which in-house Nuclear Medicine Department (MND) customers consider that the quality of service is good (personalized cutoff). We conducted a survey of the professionals who had requested at least 5 tests to the Nuclear Medicine Department. A total of 71 doctors responded (response rate: 30%). A question was added to the questionnaire for the user to establish a cutoff point for which they would consider the quality of service as good. The quality non-conformities, areas of improvement and strong points of the six questions measuring the quality of service (Likert scale 0 to 10) were compared with two different thresholds: personalized cutoff and one proposed by the service itself a priori. Test statistics: binomial and Student's t-test for paired data. A cutoff value of 7 was proposed by the service as a reference while 68.1% of respondents suggested a cutoff above 7 points (mean 7.9 points). The 6 elements of perceived quality were considered strong points with the cutoff proposed by the MND, while there were 3 detected with the personalized threshold. Thirteen percent of the answers were nonconformities with the service cutoff versus 19.2% with the personalized one, the differences being statistically significant (difference 95% CI 6.44%:0,83-12.06). The final image of the perceived quality of an in-house customer is different when using the cutoff established by the Department versus the personalized cutoff given by the respondent. Copyright © 2013 Elsevier España, S.L. and SEMNIM. All rights reserved.

A global climate niche for giant trees.

PubMed

Scheffer, Marten; Xu, Chi; Hantson, Stijn; Holmgren, Milena; Los, Sietse O; van Nes, Egbert H

2018-04-15

Rainforests are among the most charismatic as well as the most endangered ecosystems of the world. However, although the effects of climate change on tropical forests resilience is a focus of intense research, the conditions for their equally impressive temperate counterparts remain poorly understood, and it remains unclear whether tropical and temperate rainforests have fundamental similarities or not. Here we use new global data from high precision laser altimetry equipment on satellites to reveal for the first time that across climate zones 'giant forests' are a distinct and universal phenomenon, reflected in a separate mode of canopy height (~40 m) worldwide. Occurrence of these giant forests (cutoff height > 25 m) is negatively correlated with variability in rainfall and temperature. We also demonstrate that their distribution is sharply limited to situations with a mean annual precipitation above a threshold of 1,500 mm that is surprisingly universal across tropical and temperate climates. The total area with such precipitation levels is projected to increase by ~4 million km 2 globally. Our results thus imply that strategic management could in principle facilitate the expansion of giant forests, securing critically endangered biodiversity as well as carbon storage in selected regions. © 2018 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.
Microsat and Lunar-Based Imaging of Radio Bursts

NASA Technical Reports Server (NTRS)

MacDowall, R. J.; Gopalswamy, N.; Kaiser, M. L.; Demaio, L. D.; Bale, S. D.; Kasper, J. C.; Lazarus, A. J.; Howard, R. E.; Jones, D. L.; Reiner, M. J.;

2005-01-01

No present or approved spacecraft mission has the capability to provide high angular resolution imaging of solar or magnetospheric radio bursts or of the celestial sphere at frequencies below the ionospheric cutoff. Here, we describe a MIDEX-class mission to perform such imaging in the frequency range approx. 30 kHz to 15 MHz. This mission, the Solar Imaging Radio Array (SIRA), is solar and exploration-oriented, with emphasis on improved understanding and application of radio bursts associated with solar energetic particle (SEP) events and on tracking shocks and other components of coronal mass ejections (CMEs). SIRA will require 12 to 16 micro-satellites to establish a sufficient number of baselines with separations on the order of kilometers. The constellation consists of microsats located quasi-randomly on a spherical shell, initially of approx. 10 km diameter. The baseline microsat is 3-axis stabilized with body-mounted solar arrays and an articulated, earth pointing high gain antenna. The constellation will likely be placed at L1, which is the preferred location for full-time solar observations. We also discuss briefly follow-on missions that would be lunar-based with of order 10,000 dipole antennas.

Measurement and analysis of electron-neutral collision frequency in the calibrated cutoff probe

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

You, K. H.; Seo, B. H.; Kim, J. H.

2016-03-15

As collisions between electrons and neutral particles constitute one of the most representative physical phenomena in weakly ionized plasma, the electron-neutral (e-n) collision frequency is a very important plasma parameter as regards understanding the physics of this material. In this paper, we measured the e-n collision frequency in the plasma using a calibrated cutoff-probe. A highly accurate reactance spectrum of the plasma/cutoff-probe system, which is expected based on previous cutoff-probe circuit simulations [Kim et al., Appl. Phys. Lett. 99, 131502 (2011)], is obtained using the calibrated cutoff-probe method, and the e-n collision frequency is calculated based on the cutoff-probe circuitmore » model together with the high-frequency conductance model. The measured e-n collision frequency (by the calibrated cutoff-probe method) is compared and analyzed with that obtained using a Langmuir probe, with the latter being calculated from the measured electron-energy distribution functions, in wide range of gas pressure.« less
Stationary Black Holes: Uniqueness and Beyond.

PubMed

Heusler, Markus

1998-01-01

The spectrum of known black hole solutions to the stationary Einstein equations has increased in an unexpected way during the last decade. In particular, it has turned out that not all black hole equilibrium configurations are characterized by their mass, angular momentum and global charges. Moreover, the high degree of symmetry displayed by vacuum and electro-vacuum black hole space-times ceases to exist in self-gravitating non-linear field theories. This text aims to review some of the recent developments and to discuss them in the light of the uniqueness theorem for the Einstein-Maxwell system.
Reynolds number scaling of the influence of boundary layers on the global behavior of laboratory quasi-Keplerian flows

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

Edlund, E. M.; Ji, H.

2015-10-06

Here, we present fluid velocity measurements in a modified Taylor-Couette device operated in the quasi-Keplerian regime, where it is observed that nearly ideal flows exhibit self-similarity under scaling of the Reynolds number. In contrast, nonideal flows show progressive departure from ideal Couette as the Reynolds number is increased. We present a model that describes the observed departures from ideal Couette rotation as a function of the fluxes of angular momentum across the boundaries, capturing the dependence on Reynolds number and boundary conditions.
Reynolds number scaling of the influence of boundary layers on the global behavior of laboratory quasi-Keplerian flows.

PubMed

Edlund, E M; Ji, H

2015-10-01

We present fluid velocity measurements in a modified Taylor-Couette device operated in the quasi-Keplerian regime, where it is observed that nearly ideal flows exhibit self-similarity under scaling of the Reynolds number. In contrast, nonideal flows show progressive departure from ideal Couette as the Reynolds number is increased. We present a model that describes the observed departures from ideal Couette rotation as a function of the fluxes of angular momentum across the boundaries, capturing the dependence on Reynolds number and boundary conditions.
Stationary Black Holes: Uniqueness and Beyond.

PubMed

Chruściel, Piotr T; Costa, João Lopes; Heusler, Markus

2012-01-01

The spectrum of known black-hole solutions to the stationary Einstein equations has been steadily increasing, sometimes in unexpected ways. In particular, it has turned out that not all black-hole-equilibrium configurations are characterized by their mass, angular momentum and global charges. Moreover, the high degree of symmetry displayed by vacuum and electro-vacuum black-hole spacetimes ceases to exist in self-gravitating non-linear field theories. This text aims to review some developments in the subject and to discuss them in light of the uniqueness theorem for the Einstein-Maxwell system.
Virtual photon polarization and dilepton anisotropy in relativistic nucleus-nucleus collisions

NASA Astrophysics Data System (ADS)

Speranza, Enrico; Jaiswal, Amaresh; Friman, Bengt

2018-07-01

The polarization of virtual photons produced in relativistic nucleus-nucleus collisions provides information on the conditions in the emitting medium. In a hydrodynamic framework, the resulting angular anisotropy of the dilepton final state depends on the flow as well as on the transverse momentum and invariant mass of the photon. We illustrate these effects in dilepton production from quark-antiquark annihilation in the QGP phase and π+π- annihilation in the hadronic phase for a static medium in global equilibrium and for a longitudinally expanding system.
Converged three-dimensional quantum mechanical reaction probabilities for the F + H2 reaction on a potential energy surface with realistic entrance and exit channels and comparisons to results for three other surfaces

NASA Technical Reports Server (NTRS)

Lynch, Gillian C.; Halvick, Philippe; Zhao, Meishan; Truhlar, Donald G.; Yu, Chin-Hui; Kouri, Donald J.; Schwenke, David W.

1991-01-01

Accurate three-dimensional quantum mechanical reaction probabilities are presented for the reaction F + H2 yields HF + H on the new global potential energy surface 5SEC for total angular momentum J = 0 over a range of translational energies from 0.15 to 4.6 kcal/mol. It is found that the v-prime = 3 HF vibrational product state has a threshold as low as for v-prime = 2.
Late time neutrino masses, the LSND experiment, and the cosmic microwave background.

PubMed

Chacko, Z; Hall, Lawrence J; Oliver, Steven J; Perelstein, Maxim

2005-03-25

Models with low-scale breaking of global symmetries in the neutrino sector provide an alternative to the seesaw mechanism for understanding why neutrinos are light. Such models can easily incorporate light sterile neutrinos required by the Liquid Scintillator Neutrino Detector experiment. Furthermore, the constraints on the sterile neutrino properties from nucleosynthesis and large-scale structure can be removed due to the nonconventional cosmological evolution of neutrino masses and densities. We present explicit, fully realistic supersymmetric models, and discuss the characteristic signatures predicted in the angular distributions of the cosmic microwave background.
Decreasing of axial angular momentum of oceanic both fluid continental masses and its contribution to non-tidal acceleration of rotation of the Earth

NASA Astrophysics Data System (ADS)

Barkin, Yu. V.

2009-04-01

Modeling constructions have shown, that a variation of geopotential coefficients, since the second harmonic, are determined basically by redistributions of fluid masses in the top shells of the Earth [1]. Only on a variation of coefficients of the first harmonic essential influence renders displacement of the centre of mass in the basic mantle reference system. By the similar redistribution of masses it is obviously possible to estimate a variation of the axial moment of inertia of the full Earth, including an atmosphere and ocean, on a value of variation of coefficient of the second zonal harmonic of geopotential: Ä C = 2ËJ2(3I) (I = 0.3307is a dimensionless polar moment of inertia of the Earth, C is the polar moment of inertia of the Earth). According to satellite observations Ë J2 = (2.7 ± 0.4) × 10-11 1/yr[2] and, hence, we obtain an estimation ÄC = -(5.4 ± 0.8) × 10-11 1/yr. We use this value for an establishment of the new phenomenon - acceleration of return superrotation of fluids in western direction. For what we shall take advantage of known estimations of secular non-tidal acceleration of rotation of the rigid Earth: Ë?? = (6.9± 1.2) × 10-11 1/yr (corresponding variation LOD makes -0.6 ± 0.1 ms/cy) [3] and variations of angular velocity of axial rotation of the Earth because of secular increase of a polar atmosphere angular moment: -0.56 ms/cy[4]. On Salstein's data for 1970 - 2002 a positive trend of polar component of the angular momentum really exists. Corresponding reduction of duration of day is characterized by velocity-0.525 ms/cy. First of the given values has been obtained by results of observations of solar eclipses over last 2500. And the second value has been obtained on the data on variations of specified component of the angular momentum for last 60 years. Thus, in present epoch an acceleration of superrotation of an atmosphere is observed. Which results in delay of rotation of the Earth with relative acceleration Ë?? = (-6.5) × 10-11 1/yr. It means, that there is other mechanism which results in significant positive angular acceleration of rotation of the Earth ?Ë? = (13.4 ±1.2) × 10-11 (to this value there corresponds a negative variation LOD in-1.16 ± 0.10 ms/cy). The similar mechanism can be only a redistribution of oceanic masses (currents) and subsoil waters and fluids in aggregate. Thus, the data of astronomical and geophysical observations unequivocally specify that the phenomenon of strengthening of circulation of continental waters (in particular subsoil waters) in the western direction should be observed. Or negative trend in total value of the angular axial momentum of ocean and a hydrology of continents. Attributes of an intensification of the western drift of oceanic masses are seen in rather old data for 1981-1989 (Brosche et al., [5]). On these data secular changes in redistribution of oceanic masses cause reduction of LOD with velocity of ?-0.16 ms/cy. And both hemispheres northern and southern bring contributions comparable on value: ~-0.074 ms/cy (NH) and ~-0.089 ms/cy (SH). These values, certainly, are rather approached and have estimated character. In global currents at ocean the similar situation in strengthening of circulation in the western direction in present epoch should be observed. We shall emphasize, that the question is not existence of those or other planetary currents, but about their slow changes as it is described above. As the size of a variation of angular velocity because of redistribution of water masses is rather significant, it should be observed in the modern data on variations of the angular momentum of ocean and as a whole of fluid masses. Let á¹ ° is a secular variation of the angular momentum of fluid masses of the Earth in present epoch. G = C? is unperturbed value of the angular momentum of rotary motion of full system the Earth. According to the mentioned above works the following estimations of secular variations of the axial angular momentum of ocean and its northern and southern hemispheres [5] were obtained: ( ) ( ) ( ) ËRG = - 0.12 ms/cy, RËG = - 0.12 ms/cy, ËRG = - 0.24 ms/cy, ON OS O and according to work [6] for hydrological, oceanic and their total fluids making the axial angular momentum the following estimations have been obtained: ( ) ( ) ( ) ËRG = - 0.34 ms/cy, ËRG = - 0.22 ms/cy, RËG = - 0.55 ms/cy. H O H+O Results will be coordinated among themselves. For example, for the full axial momentum of all fluids (atmospheres, ocean, continental and ground) in the specified two models turn out small values:( ) ËRC0?A+H+O = -0.03 ms/cy, ( ) RËC0 ?A+H+O = -0.05 ms/cy, as it follows from dynamic conclusions about non-tidal acceleration of rotation of the Earth. Excluding from consideration a time interval 1997.0-1999.0, which corresponds to spasmodic changes of all natural processes of the Earth (Barkin, 2002), for velocity of decrease of the hydrological and oceanic angular momentums before and after the specified period we obtain rough estimates: - 0.7-0.9 ÷ ms/cy. These estimations at least do not contradict the basic conclusions to the given work about increase of the western displacement and currents of fluids of the Earth. More exact analysis will need the data of supervision for longer time intervals. The similar rough estimate on the data [5] turns out for oceanic making secular changes of the angular momentum. It gives negative change LOD with velocity -0.16 ms/cy. Thus, it is possible to assume, that there is an effective mechanism of secular increase of streams of water (fluid) masses on continents in the western direction. On the other hand according to work [5] roughly it is possible to estimate trend of the angular momentum of in common oceanic and hydrological fluids. It appears, that redistributions of these masses in present epoch results in acceleration of rotation of the Earth. The appropriate reduction of duration of day here makes approximately-0.52 ms/cy. Thus strengthening of redistribution of terrestrial waters and fluids in the western direction really proves to be true. These estimations are obtained at exception of the period 1997.0-1999.0 when there was rather fast spasmodic change (increase) of duration of day approximately on 0.038 ms. References [1] Barkin Yu.V. (2007) Celestial geodynamics and solution of the fundamental problems of geodesy, gravimetry and geophysics. Proceedings of IUGG XXIV General Assembly, Perugia, Italy 2007: Earth: Our Changing Planet (Perugia, Italy, July 2-13, 2007), (S) - IASPEI, JSS011, p. 2149. www. iugg2007perugia.it. [2] Cheng M.R., Shum C.K. and Tapley B.D. (1997) Determination of long-periodic changes in the Earth's gravity field from satellite laser ranging observations. Journal of Geophysical research, V. 102, No. B10. pp. 22377-22390. [3] Stephenson F.R. and Morrison L.V. (1995) Long term fluctuations in the Earth's rotation:700 BC to AD 1990, Phil. Trans. R. Soc. Lond., A, 351, p. 165-202. [4] Abarca del Rio R. (1999) The influence of global warming in Earth rotation speed. Ann. Geophys., 17, 806-811. [5] Brosche P., Wunsch J., Maier-Reimer E., Segschneider J., Sundermann J. (1997) The axial angular momentum of the general circulation of the oceans. Astron. Nachr. 318, V.3, 193-199. [6] Chen J. (2005) Global mass balance an the length-of-day variation. Journal of Geophysical research, V. 110, B08404, doi: 10.1029/2004JB003474. [7] Barkin Yu.V. (2002) Explanation of endogenous activity of planets and satellites and its cyclicity. Izvestia cekzii nauk o Zemle. Rus. Acad. of Nat. Sciences, Issue 9, December 2002, M.: VINITI, pp. 45-97. In Russian.
ANISOTROPY IN COSMIC-RAY ARRIVAL DIRECTIONS IN THE SOUTHERN HEMISPHERE BASED ON SIX YEARS OF DATA FROM THE ICECUBE DETECTOR

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

Aartsen, M. G.; Abraham, K.; Ackermann, M.

The IceCube Neutrino Observatory accumulated a total of 318 billion cosmic-ray-induced muon events between 2009 May and 2015 May. This data set was used for a detailed analysis of the sidereal anisotropy in the arrival directions of cosmic rays in the TeV to PeV energy range. The observed global sidereal anisotropy features large regions of relative excess and deficit, with amplitudes of the order of 10{sup 3} up to about 100 TeV. A decomposition of the arrival direction distribution into spherical harmonics shows that most of the power is contained in the low-multipole ( ℓ ≤ 4) moments. However, highermore » multipole components are found to be statistically significant down to an angular scale of less than 10°, approaching the angular resolution of the detector. Above 100 TeV, a change in the morphology of the arrival direction distribution is observed, and the anisotropy is characterized by a wide relative deficit whose amplitude increases with primary energy up to at least 5 PeV, the highest energies currently accessible to IceCube. No time dependence of the large- and small-scale structures is observed in the period of six years covered by this analysis. The high-statistics data set reveals more details of the properties of the anisotropy and is potentially able to shed light on the various physical processes that are responsible for the complex angular structure and energy evolution.« less
A method for optimizing the cosine response of solar UV diffusers

NASA Astrophysics Data System (ADS)

Pulli, Tomi; Kärhä, Petri; Ikonen, Erkki

2013-07-01

Instruments measuring global solar ultraviolet (UV) irradiance at the surface of the Earth need to collect radiation from the entire hemisphere. Entrance optics with angular response as close as possible to the ideal cosine response are necessary to perform these measurements accurately. Typically, the cosine response is obtained using a transmitting diffuser. We have developed an efficient method based on a Monte Carlo algorithm to simulate radiation transport in the solar UV diffuser assembly. The algorithm takes into account propagation, absorption, and scattering of the radiation inside the diffuser material. The effects of the inner sidewalls of the diffuser housing, the shadow ring, and the protective weather dome are also accounted for. The software implementation of the algorithm is highly optimized: a simulation of 109 photons takes approximately 10 to 15 min to complete on a typical high-end PC. The results of the simulations agree well with the measured angular responses, indicating that the algorithm can be used to guide the diffuser design process. Cost savings can be obtained when simulations are carried out before diffuser fabrication as compared to a purely trial-and-error-based diffuser optimization. The algorithm was used to optimize two types of detectors, one with a planar diffuser and the other with a spherically shaped diffuser. The integrated cosine errors—which indicate the relative measurement error caused by the nonideal angular response under isotropic sky radiance—of these two detectors were calculated to be f2=1.4% and 0.66%, respectively.
Anisotropy in Cosmic-Ray Arrival Directions in the Southern Hemisphere Based on Six Years of Data from the IceCube Detector

NASA Astrophysics Data System (ADS)

Aartsen, M. G.; Abraham, K.; Ackermann, M.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Ahrens, M.; Altmann, D.; Anderson, T.; Ansseau, I.; Anton, G.; Archinger, M.; Arguelles, C.; Arlen, T. C.; Auffenberg, J.; Bai, X.; Barwick, S. W.; Baum, V.; Bay, R.; Beatty, J. J.; Becker Tjus, J.; Becker, K.-H.; Beiser, E.; BenZvi, S.; Berghaus, P.; Berley, D.; Bernardini, E.; Bernhard, A.; Besson, D. Z.; Binder, G.; Bindig, D.; Bissok, M.; Blaufuss, E.; Blumenthal, J.; Boersma, D. J.; Bohm, C.; Börner, M.; Bos, F.; Bose, D.; Böser, S.; Botner, O.; Braun, J.; Brayeur, L.; Bretz, H.-P.; Buzinsky, N.; Casey, J.; Casier, M.; Cheung, E.; Chirkin, D.; Christov, A.; Clark, K.; Classen, L.; Coenders, S.; Collin, G. H.; Conrad, J. M.; Cowen, D. F.; Cruz Silva, A. H.; Daughhetee, J.; Davis, J. C.; Day, M.; de André, J. P. A. M.; De Clercq, C.; del Pino Rosendo, E.; Dembinski, H.; De Ridder, S.; Desiati, P.; de Vries, K. D.; de Wasseige, G.; de With, M.; DeYoung, T.; Díaz-Vélez, J. C.; di Lorenzo, V.; Dujmovic, H.; Dumm, J. P.; Dunkman, M.; Eberhardt, B.; Ehrhardt, T.; Eichmann, B.; Euler, S.; Evenson, P. A.; Fahey, S.; Fazely, A. R.; Feintzeig, J.; Felde, J.; Filimonov, K.; Finley, C.; Flis, S.; Fösig, C.-C.; Fuchs, T.; Gaisser, T. K.; Gaior, R.; Gallagher, J.; Gerhardt, L.; Ghorbani, K.; Gier, D.; Gladstone, L.; Glagla, M.; Glüsenkamp, T.; Goldschmidt, A.; Golup, G.; Gonzalez, J. G.; Góra, D.; Grant, D.; Griffith, Z.; Ha, C.; Haack, C.; Haj Ismail, A.; Hallgren, A.; Halzen, F.; Hansen, E.; Hansmann, B.; Hansmann, T.; Hanson, K.; Hebecker, D.; Heereman, D.; Helbing, K.; Hellauer, R.; Hickford, S.; Hignight, J.; Hill, G. C.; Hoffman, K. D.; Hoffmann, R.; Holzapfel, K.; Homeier, A.; Hoshina, K.; Huang, F.; Huber, M.; Huelsnitz, W.; Hulth, P. O.; Hultqvist, K.; In, S.; Ishihara, A.; Jacobi, E.; Japaridze, G. S.; Jeong, M.; Jero, K.; Jones, B. J. P.; Jurkovic, M.; Kappes, A.; Karg, T.; Karle, A.; Katz, U.; Kauer, M.; Keivani, A.; Kelley, J. L.; Kemp, J.; Kheirandish, A.; Kim, M.; Kintscher, T.; Kiryluk, J.; Klein, S. R.; Kohnen, G.; Koirala, R.; Kolanoski, H.; Konietz, R.; Köpke, L.; Kopper, C.; Kopper, S.; Koskinen, D. J.; Kowalski, M.; Krings, K.; Kroll, G.; Kroll, M.; Krückl, G.; Kunnen, J.; Kunwar, S.; Kurahashi, N.; Kuwabara, T.; Labare, M.; Lanfranchi, J. L.; Larson, M. J.; Lennarz, D.; Lesiak-Bzdak, M.; Leuermann, M.; Leuner, J.; Lu, L.; Lünemann, J.; Madsen, J.; Maggi, G.; Mahn, K. B. M.; Mandelartz, M.; Maruyama, R.; Mase, K.; Matis, H. S.; Maunu, R.; McNally, F.; Meagher, K.; Medici, M.; Meier, M.; Meli, A.; Menne, T.; Merino, G.; Meures, T.; Miarecki, S.; Middell, E.; Mohrmann, L.; Montaruli, T.; Morse, R.; Nahnhauer, R.; Naumann, U.; Neer, G.; Niederhausen, H.; Nowicki, S. C.; Nygren, D. R.; Obertacke Pollmann, A.; Olivas, A.; Omairat, A.; O'Murchadha, A.; Palczewski, T.; Pandya, H.; Pankova, D. V.; Paul, L.; Pepper, J. A.; Pérez de los Heros, C.; Pfendner, C.; Pieloth, D.; Pinat, E.; Posselt, J.; Price, P. B.; Przybylski, G. T.; Quinnan, M.; Raab, C.; Rädel, L.; Rameez, M.; Rawlins, K.; Reimann, R.; Relich, M.; Resconi, E.; Rhode, W.; Richman, M.; Richter, S.; Riedel, B.; Robertson, S.; Rongen, M.; Rott, C.; Ruhe, T.; Ryckbosch, D.; Sabbatini, L.; Sander, H.-G.; Sandrock, A.; Sandroos, J.; Sarkar, S.; Schatto, K.; Schimp, M.; Schlunder, P.; Schmidt, T.; Schoenen, S.; Schöneberg, S.; Schönwald, A.; Schumacher, L.; Seckel, D.; Seunarine, S.; Soldin, D.; Song, M.; Spiczak, G. M.; Spiering, C.; Stahlberg, M.; Stamatikos, M.; Stanev, T.; Stasik, A.; Steuer, A.; Stezelberger, T.; Stokstad, R. G.; Stössl, A.; Ström, R.; Strotjohann, N. L.; Sullivan, G. W.; Sutherland, M.; Taavola, H.; Taboada, I.; Tatar, J.; Ter-Antonyan, S.; Terliuk, A.; Tešić, G.; Tilav, S.; Toale, P. A.; Tobin, M. N.; Toscano, S.; Tosi, D.; Tselengidou, M.; Turcati, A.; Unger, E.; Usner, M.; Vallecorsa, S.; Vandenbroucke, J.; van Eijndhoven, N.; Vanheule, S.; van Santen, J.; Veenkamp, J.; Vehring, M.; Voge, M.; Vraeghe, M.; Walck, C.; Wallace, A.; Wallraff, M.; Wandkowsky, N.; Weaver, Ch.; Wendt, C.; Westerhoff, S.; Whelan, B. J.; Wiebe, K.; Wiebusch, C. H.; Wille, L.; Williams, D. R.; Wills, L.; Wissing, H.; Wolf, M.; Wood, T. R.; Woschnagg, K.; Xu, D. L.; Xu, X. W.; Xu, Y.; Yanez, J. P.; Yodh, G.; Yoshida, S.; Zoll, M.; IceCube Collaboration

2016-08-01

The IceCube Neutrino Observatory accumulated a total of 318 billion cosmic-ray-induced muon events between 2009 May and 2015 May. This data set was used for a detailed analysis of the sidereal anisotropy in the arrival directions of cosmic rays in the TeV to PeV energy range. The observed global sidereal anisotropy features large regions of relative excess and deficit, with amplitudes of the order of 10-3 up to about 100 TeV. A decomposition of the arrival direction distribution into spherical harmonics shows that most of the power is contained in the low-multipole (ℓ ≤ 4) moments. However, higher multipole components are found to be statistically significant down to an angular scale of less than 10°, approaching the angular resolution of the detector. Above 100 TeV, a change in the morphology of the arrival direction distribution is observed, and the anisotropy is characterized by a wide relative deficit whose amplitude increases with primary energy up to at least 5 PeV, the highest energies currently accessible to IceCube. No time dependence of the large- and small-scale structures is observed in the period of six years covered by this analysis. The high-statistics data set reveals more details of the properties of the anisotropy and is potentially able to shed light on the various physical processes that are responsible for the complex angular structure and energy evolution.
Elastic response of zone axis (001)-oriented PWA 1480 single crystal: The influence of secondary orientation

NASA Technical Reports Server (NTRS)

Kalluri, Sreeramesh; Abdul-Aziz, Ali; Mcgaw, Michael A.

1991-01-01

The influence of secondary orientation on the elastic response of a zone axis (001)-oriented nickel-base single-crystal superalloy, PWA 1480, was investigated under mechanical loading conditions by applying finite element techniques. Elastic stress analyses were performed with a commercially available finite element code. Secondary orientation of the single-crystal superalloy was offset with respect to the global coordinate system in increments from 0 to 90 deg and stresses developed within the single crystal were determined for each loading condition. The results indicated that the stresses were strongly influenced by the angular offset between the secondary crystal orientation and the global coordinate system. The degree of influence was found to vary with the type of loading condition (mechanical, thermal, or combined) imposed on the single-crystal superalloy.
Predicting Earth orientation changes from global forecasts of atmosphere-hydrosphere dynamics

NASA Astrophysics Data System (ADS)

Dobslaw, Henryk; Dill, Robert

2018-02-01

Effective Angular Momentum (EAM) functions obtained from global numerical simulations of atmosphere, ocean, and land surface dynamics are routinely processed by the Earth System Modelling group at Deutsches GeoForschungsZentrum. EAM functions are available since January 1976 with up to 3 h temporal resolution. Additionally, 6 days-long EAM forecasts are routinely published every day. Based on hindcast experiments with 305 individual predictions distributed over 15 months, we demonstrate that EAM forecasts improve the prediction accuracy of the Earth Orientation Parameters at all forecast horizons between 1 and 6 days. At day 6, prediction accuracy improves down to 1.76 mas for the terrestrial pole offset, and 2.6 mas for Δ UT1, which correspond to an accuracy increase of about 41% over predictions published in Bulletin A by the International Earth Rotation and Reference System Service.
Effects of the change in cutoff values for human epidermal growth factor receptor 2 status by immunohistochemistry and fluorescence in situ hybridization: a study comparing conventional brightfield microscopy, image analysis-assisted microscopy, and interobserver variation.

PubMed

Atkinson, Roscoe; Mollerup, Jens; Laenkholm, Anne-Vibeke; Verardo, Mark; Hawes, Debra; Commins, Deborah; Engvad, Birte; Correa, Adrian; Ehlers, Charlotte Cort; Nielsen, Kirsten Vang

2011-08-01

New guidelines for HER2 testing have been introduced. To evaluate the difference in HER2 assessment after introduction of new cutoff levels for both immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) and to compare interobserver agreement and time to score between image analysis and conventional microscopy. Samples from 150 patients with breast cancer were scored by 7 pathologists using conventional microscopy, with a cutoff of both 10% and 30% IHC-stained cells, and using automated microscopy with image analysis. The IHC results were compared individually and to HER2 status as determined by FISH, using both the approved cutoff of 2.0 and the recently introduced cutoff of 2.2. High concordance was found in IHC scoring among the 7 pathologists. The 30% cutoff led to slightly fewer positive IHC observations. Introduction of a FISH equivocal zone affected 4% of the FISH scores. If cutoff for FISH is kept at 2.0, no difference in patient selection is found between the 10% and the 30% IHC cutoff. Among the 150 breast cancer samples, the new 30% IHC and 2.2 FISH cutoff levels resulted in one case without a firm diagnosis because both IHC and FISH were equivocal. Automated microscopy and image analysis-assisted IHC led to significantly better interobserver agreement among the 7 pathologists, with an increase in mean scoring time of only about 30 seconds per slide. The change in cutoff levels led to a higher concordance between IHC and FISH, but fewer samples were classified as HER2 positive.
SAMPEX Measurements of Geomagnetic-Cutoff Variations During the 4/21/02 Solar Energetic Particle Event

NASA Astrophysics Data System (ADS)

Labrador, A.; Leske, R.; Kanekal, S.; Klecker, B.; Looper, M.; Mazur, J.; Mewaldt, R.

2002-12-01

During large solar energetic particle (SEP) events the entry of solar and interplanetary energetic particles into the upper atmosphere is controlled by the geomagnetic cutoff. We define the cutoff latitude (Λ c) for a given rigidity particle to be effectively the minimum invariant latitude down to which particles can reach the upper atmosphere. The instruments on the polar-orbiting SAMPEX spacecraft have been used to measure geomagnetic cutoffs during a large sample of SEP events from solar cycle 23. During those events in which there is an associated geomagnetic storm, there are often large cutoff variations of as much as 5° to 10° in invariant latitude over the course of the event. This paper will combine measurements from the HILT, MAST, and PET instruments on SAMPEX to provide a comprehensive view of geomagnetic cutoff variations during the large SEP event of 4/21/02. We find that during the first two days of the event the cutoff latitude for ~30 MeV protons was at typical quiet-time levels. On April 23, following the arrival of a strong interplanetary shock, there was a sudden drop in the cutoff that lasted ~12 hours, with sizable local-time differences. During the next two days the cutoff steadily increased, giving a total variation of ~5° over the five days of the event. We combine these measurements of cutoff variations with measurements of the composition and energy spectra in the 4/21/02 event in order to estimate changes in the area of the polar caps over which particles of a given rigidity had access to the upper atmosphere.
The life of a meander bend: Connecting shape and dynamics via analysis of a numerical model

NASA Astrophysics Data System (ADS)

Schwenk, Jon; Lanzoni, Stefano; Foufoula-Georgiou, Efi

2015-04-01

Analysis of bend-scale meandering river dynamics is a problem of theoretical and practical interest. This work introduces a method for extracting and analyzing the history of individual meander bends from inception until cutoff (called "atoms") by tracking backward through time the set of two cutoff nodes in numerical meander migration models. Application of this method to a simplified yet physically based model provides access to previously unavailable bend-scale meander dynamics over long times and at high temporal resolutions. We find that before cutoffs, the intrinsic model dynamics invariably simulate a prototypical cutoff atom shape we dub simple. Once perturbations from cutoffs occur, two other archetypal cutoff planform shapes emerge called long and round that are distinguished by a stretching along their long and perpendicular axes, respectively. Three measures of meander migration—growth rate, average migration rate, and centroid migration rate—are introduced to capture the dynamic lives of individual bends and reveal that similar cutoff atom geometries share similar dynamic histories. Specifically, through the lens of the three shape types, simples are seen to have the highest growth and average migration rates, followed by rounds, and finally longs. Using the maximum average migration rate as a metric describing an atom's dynamic past, we show a strong connection between it and two metrics of cutoff geometry. This result suggests both that early formative dynamics may be inferred from static cutoff planforms and that there exists a critical period early in a meander bend's life when its dynamic trajectory is most sensitive to cutoff perturbations. An example of how these results could be applied to Mississippi River oxbow lakes with unknown historic dynamics is shown. The results characterize the underlying model and provide a framework for comparisons against more complex models and observed dynamics.
Particle Environment Package (PEP) for the ESA JUICE mission

NASA Astrophysics Data System (ADS)

Barabash, Stas; Brandt, Pontus; Wurz, Peter; PEP Team

2016-10-01

PEP is a suite of six (6) sensors arranged in 4 units to measure charged and neutral particles in the Jupiter magnetospheres and at the moons to answer four overarching science questions:1. How does the corotating magnetosphere of Jupiter interact with the complex and diverse environment of Ganymede?2. How does the rapidly rotating magnetosphere of Jupiter interact with the seemingly inert Callisto?3. What are the governing mechanisms and their global impacts of release of material into the Jovian magnetosphere from seemingly inert Europa and active Io?4. How do internal and solar wind drivers cause such energetic, time variable and multi-scale phenomena in the steadily rotating giant magnetosphere of Jupiter?PEP measures positive and negative ions, electrons, exospheric neutral gas, thermal plasma and energetic neutral atoms present in all domains of the Jupiter system over nine decades of energy from < 0.001 eV to > 1 MeV with full angular coverage.PEP provides instantaneous measurements of 3D flow of the ion plasma and composition to understand the magnetosphere and magnetosphere-moon interactions. It also measures instantaneously 3D electron plasma to investigate auroral processes at the moon and Jupiter. Measurements of the angular distributions of energetic electrons at sub-second resolution probe the acceleration mechanisms and magnetic field topology and boundaries.PEP combines global imaging via remote sensing using energetic neutral atoms (ENA) with in-situ measurements and performs global imaging of Europa/Io tori and magnetosphere combined with energetic ion measurements. Using low energy ENAs originating from the particle - surface interaction PEP investigate space weathering of the icy moons by precipitation particles. PEP will first-ever directly sample of the exospheres of Europa, Ganymede, and Callisto with extremely high mass resolution (M/ΔM > 1100).The PEP sensors are (1) an ion mass analyzer, (2) an electron spectrometer, (3) a low energy ENA imager, (4) a high energy ENA and energetic ions imager, (5) an energetic electron sensor, and (6) a neutral gas and ions mass spectrometer.

The ATLASGAL survey: distribution of cold dust in the Galactic plane. Combination with Planck data

NASA Astrophysics Data System (ADS)

Csengeri, T.; Weiss, A.; Wyrowski, F.; Menten, K. M.; Urquhart, J. S.; Leurini, S.; Schuller, F.; Beuther, H.; Bontemps, S.; Bronfman, L.; Henning, Th.; Schneider, N.

2016-01-01

Context. Sensitive ground-based submillimeter surveys, such as ATLASGAL, provide a global view on the distribution of cold dense gas in the Galactic plane at up to two-times better angular-resolution compared to recent space-based surveys with Herschel. However, a drawback of ground-based continuum observations is that they intrinsically filter emission, at angular scales larger than a fraction of the field-of-view of the array, when subtracting the sky noise in the data processing. The lost information on the distribution of diffuse emission can be, however, recovered from space-based, all-sky surveys with Planck. Aims: Here we aim to demonstrate how this information can be used to complement ground-based bolometer data and present reprocessed maps of the APEX Telescope Large Area Survey of the Galaxy (ATLASGAL) survey. Methods: We use the maps at 353 GHz from the Planck/HFI instrument, which performed a high sensitivity all-sky survey at a frequency close to that of the APEX/LABOCA array, which is centred on 345 GHz. Complementing the ground-based observations with information on larger angular scales, the resulting maps reveal the distribution of cold dust in the inner Galaxy with a larger spatial dynamic range. We visually describe the observed features and assess the global properties of dust distribution. Results: Adding information from large angular scales helps to better identify the global properties of the cold Galactic interstellar medium. To illustrate this, we provide mass estimates from the dust towards the W43 star-forming region and estimate a column density contrast of at least a factor of five between a low intensity halo and the star-forming ridge. We also show examples of elongated structures extending over angular scales of 0.5°, which we refer to as thin giant filaments. Corresponding to > 30 pc structures in projection at a distance of 3 kpc, these dust lanes are very extended and show large aspect ratios. We assess the fraction of dense gas by determining the contribution of the APEX/LABOCA maps to the combined maps, and estimate 2-5% for the dense gas fraction (corresponding to Av> 7 mag) on average in the Galactic plane. We also show probability distribution functions of the column density (N-PDF), which reveal the typically observed log-normal distribution for low column density and exhibit an excess at high column densities. As a reference for extragalactic studies, we show the line-of-sight integrated N-PDF of the inner Galaxy, and derive a contribution of this excess to the total column density of ~ 2.2%, corresponding to NH2 = 2.92 × 1022 cm-2. Taking the total flux density observed in the maps, we provide an independent estimate of the mass of molecular gas in the inner Galaxy of ~ 1 × 109 M⊙, which is consistent with previous estimates using CO emission. From the mass and dense gas fraction (fDG), we estimate a Galactic SFR of Ṁ = 1.3 M⊙ yr-1. Conclusions: Retrieving the extended emission helps to better identify massive giant filaments which are elongated and confined structures. We show that the log-normal distribution of low column density gas is ubiquitous in the inner Galaxy. While the distribution of diffuse gas is relatively homogenous in the inner Galaxy, the central molecular zone (CMZ) stands out with a higher dense gas fraction despite its low star formation efficiency.Altogether our findings explain well the observed low star formation efficiency of the Milky Way by the low fDG in the Galactic ISM. In contrast, the high fDG observed towards the CMZ, despite its low star formation activity, suggests that, in that particular region of our Galaxy, high density gas is not the bottleneck for star formation.
Determination of optimal cutoff value to accurately identify glucose-6-phosphate dehydrogenase-deficient heterozygous female neonates.

PubMed

Miao, Jing-Kun; Chen, Qi-Xiong; Bao, Li-Ming; Huang, Yi; Zhang, Juan; Wan, Ke-Xing; Yi, Jing; Wang, Shi-Yi; Zou, Lin; Li, Ting-Yu

2013-09-23

Conventional screening tests to assess G6PD deficiency use a low cutoff value of 2.10 U/gHb which may not be adequate for detecting females with heterozygous deficiency. The aim of present study was to determine an appropriate cutoff value with increased sensitivity in identifying G6PD-deficient heterozygous females. G6PD activity analysis was performed on 51,747 neonates using semi-quantitative fluorescent spot test. Neonates suspected with G6PD deficiency were further analyzed using quantitatively enzymatic assay and for common G6PD mutations. The cutoff values of G6PD activity were estimated using the receiver operating characteristic curve. Our results demonstrated that using 2.10 U/g Hb as a cutoff, the sensitivity of the assay to detect female neonates with G6PD heterozygous deficiency was 83.3%, as compared with 97.6% using 2.55 U/g Hb as a cutoff. The high cutoff identified 21% (8/38) of the female neonates with partial G6PD deficiency which were not detected with 2.10 U/g Hb. Our study found that high cutoffs, 2.35 and 2.55 U/g Hb, would increase assay's sensitivity to identify male and female G6PD deficiency neonates, respectively. We established a reliable cutoff value of G6PD activity with increased sensitivity in identifying female newborns with partial G6PD deficiency. Copyright © 2013 Elsevier B.V. All rights reserved.
Accuracy of different cutoff points of body mass index to identify overweight according to body fat values estimated by DEXA.

PubMed

Anzolin, Caroline Cristina; Silva, Diego Augusto Santos; Zanuto, Edner Fernando; Cayres, Suziane Ungari; Codogno, Jamile Sanches; Costa Junior, Paulo; Machado, Dalmo Roberto Lopes; Christofaro, Diego Giulliano Destro

To evaluate the sensitivity and specificity of different cutoff points of body mass index for predicting overweight/obesity according to body fat values estimated by DEXA among Brazilian adolescents. Cross-sectional study including 229 male adolescents aged 10-15 years, in which body adiposity and anthropometric measures were assessed. Nutritional status was classified by BMI according to cutoff points described in scientific literature. Moderate agreements were observed between body fat estimated by DEXA and cutoffs proposed by Cole et al. (K=0.61), Conde and Monteiro (K=0.65), Must et al. (K=0.61) and WHO (K=0.63). The BMI in continuous form showed good agreement with the Dexa (ICC=0.72). The highest sensitivity was observed for cutoff by Conde and Monteiro (0.74 [0.62, 0.84]) and the highest specificity by Cole et al. (0.98 [0.94, 0.99]). For the areas under the ROC curve of cutoff points analyzed, significant difference comparing the cutoff points by Cole et al. and Conde and Monteiro (0.0449 [0.00294, 0.0927]) was observed. The cutoff proposed by Conde and Monteiro was more sensitive in identifying overweight and obesity when compared to the reference method, and the cutoff proposed by Cole et al. presented the highest specificity for such outcomes. Copyright © 2016 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.
Absolute Plate Velocities from Seismic Anisotropy: Importance of Correlated Errors

NASA Astrophysics Data System (ADS)

Gordon, R. G.; Zheng, L.; Kreemer, C.

2014-12-01

The orientation of seismic anisotropy inferred beneath the interiors of plates may provide a means to estimate the motions of the plate relative to the deeper mantle. Here we analyze a global set of shear-wave splitting data to estimate plate motions and to better understand the dispersion of the data, correlations in the errors, and their relation to plate speed. The errors in plate motion azimuths inferred from shear-wave splitting beneath any one tectonic plate are shown to be correlated with the errors of other azimuths from the same plate. To account for these correlations, we adopt a two-tier analysis: First, find the pole of rotation and confidence limits for each plate individually. Second, solve for the best fit to these poles while constraining relative plate angular velocities to consistency with the MORVEL relative plate angular velocities. Our preferred set of angular velocities, SKS-MORVEL, is determined from the poles from eight plates weighted proportionally to the root-mean-square velocity of each plate. SKS-MORVEL indicates that eight plates (Amur, Antarctica, Caribbean, Eurasia, Lwandle, Somalia, Sundaland, and Yangtze) have angular velocities that differ insignificantly from zero. The net rotation of the lithosphere is 0.25±0.11º Ma-1 (95% confidence limits) right-handed about 57.1ºS, 68.6ºE. The within-plate dispersion of seismic anisotropy for oceanic lithosphere (σ=19.2°) differs insignificantly from that for continental lithosphere (σ=21.6°). The between-plate dispersion, however, is significantly smaller for oceanic lithosphere (σ=7.4°) than for continental lithosphere (σ=14.7°). Two of the slowest-moving plates, Antarctica (vRMS=4 mm a-1, σ=29°) and Eurasia (vRMS=3 mm a-1, σ=33°), have two of the largest within-plate dispersions, which may indicate that a plate must move faster than ≈5 mm a-1 to result in seismic anisotropy useful for estimating plate motion.
Beam propagation factor of partially coherent flat-topped beams in a turbulent atmosphere.

PubMed

Dan, Youquan; Zhang, Bin

2008-09-29

The Wigner distribution function (WDF) has been used to study the beam propagation factor (M(2)-factor) for partially coherent flat-topped (PCFT) beams with circular symmetry in a turbulent atmosphere. Based on the extended Huygens-Fresnel principle and the definition of the WDF, an expression for the WDF of PCFT beams in turbulence has been given. By use of the second-order moments of the WDF, the analytical formulas for the root-mean-square (rms) spatial width, the rms angular width, and the M(2)-factor of PCFT beams in turbulence have been derived, which can be applied to cases of different spatial power spectra of the refractive index fluctuations. The rms angular width and the M(2)-factor of PCFT beams in turbulence have been discussed with numerical examples. It can be shown that the M(2)-factor of PCFT beams in turbulence depends on the beam order, degree of global coherence of the source, waist width, wavelength, spatial power spectrum of the refractive index fluctuations, and propagation distance.
Limit of Kerr-de Sitter spacetime with infinite angular-momentum parameter a

NASA Astrophysics Data System (ADS)

Mars, Marc; Paetz, Tim-Torben; Senovilla, José M. M.

2018-01-01

We consider the limit a →∞ of the Kerr-de Sitter spacetime. The spacetime is a Petrov type-D solution of the vacuum Einstein field equations with a positive cosmological constant Λ , vanishing Mars-Simon tensor and conformally flat ℐ . It possesses an Abelian 2-dimensional group of symmetries whose orbits are spacelike or timelike in different regions, and it includes, as a particular case, de Sitter spacetime. The global structure of the solution is analyzed in detail, with particular attention to its Killing horizons: they are foliated by noncompact marginally trapped surfaces of finite area, and one of them "touches" the curvature singularity, which resembles a null 2-dimensional surface. Outside the region between these horizons there exist trapped surfaces that again are noncompact. The solution contains, apart from Λ , a unique free parameter which can be related to the angular momentum of the nonsingular horizon in a precise way. A maximal extension of the (axis of the) spacetime is explicitly built. We also analyze the structure of ℐ , whose topology is R3.
Excitation of Earth Rotation Variations "Observed" by Time-Variable Gravity

NASA Technical Reports Server (NTRS)

Chao, Ben F.; Cox, C. M.

2005-01-01

Time variable gravity measurements have been made over the past two decades using the space geodetic technique of satellite laser ranging, and more recently by the GRACE satellite mission with improved spatial resolutions. The degree-2 harmonic components of the time-variable gravity contain important information about the Earth s length-of-day and polar motion excitation functions, in a way independent to the traditional "direct" Earth rotation measurements made by, for example, the very-long-baseline interferometry and GPS. In particular, the (degree=2, order= 1) components give the mass term of the polar motion excitation; the (2,O) component, under certain mass conservation conditions, gives the mass term of the length-of-day excitation. Combining these with yet another independent source of angular momentum estimation calculated from global geophysical fluid models (for example the atmospheric angular momentum, in both mass and motion terms), in principle can lead to new insights into the dynamics, particularly the role or the lack thereof of the cores, in the excitation processes of the Earth rotation variations.
The ALMA Phasing System: A Beamforming Capability for Ultra-high-resolution Science at (Sub)Millimeter Wavelengths

NASA Astrophysics Data System (ADS)

Matthews, L. D.; Crew, G. B.; Doeleman, S. S.; Lacasse, R.; Saez, A. F.; Alef, W.; Akiyama, K.; Amestica, R.; Anderson, J. M.; Barkats, D. A.; Baudry, A.; Broguière, D.; Escoffier, R.; Fish, V. L.; Greenberg, J.; Hecht, M. H.; Hiriart, R.; Hirota, A.; Honma, M.; Ho, P. T. P.; Impellizzeri, C. M. V.; Inoue, M.; Kohno, Y.; Lopez, B.; Martí-Vidal, I.; Messias, H.; Meyer-Zhao, Z.; Mora-Klein, M.; Nagar, N. M.; Nishioka, H.; Oyama, T.; Pankratius, V.; Perez, J.; Phillips, N.; Pradel, N.; Rottmann, H.; Roy, A. L.; Ruszczyk, C. A.; Shillue, B.; Suzuki, S.; Treacy, R.

2018-01-01

The Atacama Millimeter/submillimeter Array (ALMA) Phasing Project (APP) has developed and deployed the hardware and software necessary to coherently sum the signals of individual ALMA antennas and record the aggregate sum in Very Long Baseline Interferometry (VLBI) Data Exchange Format. These beamforming capabilities allow the ALMA array to collectively function as the equivalent of a single large aperture and participate in global VLBI arrays. The inclusion of phased ALMA in current VLBI networks operating at (sub)millimeter wavelengths provides an order of magnitude improvement in sensitivity, as well as enhancements in u–v coverage and north–south angular resolution. The availability of a phased ALMA enables a wide range of new ultra-high angular resolution science applications, including the resolution of supermassive black holes on event horizon scales and studies of the launch and collimation of astrophysical jets. It also provides a high-sensitivity aperture that may be used for investigations such as pulsar searches at high frequencies. This paper provides an overview of the ALMA Phasing System design, implementation, and performance characteristics.
A Reduced Model for the Magnetorotational Instability

NASA Astrophysics Data System (ADS)

Jamroz, Ben; Julien, Keith; Knobloch, Edgar

2008-11-01

The magnetorotational instability is investigated within the shearing box approximation in the large Elsasser number regime. In this regime, which is of fundamental importance to astrophysical accretion disk theory, shear is the dominant source of energy, but the instability itself requires the presence of a weaker vertical magnetic field. Dissipative effects are weaker still. However, they are sufficiently large to permit a nonlinear feedback mechanism whereby the turbulent stresses generated by the MRI act on and modify the local background shear in the angular velocity profile. To date this response has been omitted in shearing box simulations and is captured by a reduced pde model derived here from the global MHD fluid equations using multiscale asymptotic perturbation theory. Results from numerical simulations of the reduced pde model indicate a linear phase of exponential growth followed by a nonlinear adjustment to algebraic growth and decay in the fluctuating quantities. Remarkably, the velocity and magnetic field correlations associated with these algebraic growth and decay laws conspire to achieve saturation of the angular momentum transport. The inclusion of subdominant ohmic dissipation arrests the algebraic growth of the fluctuations on a longer, dissipative time scale.
26 CFR 1.585-7 - Elective cut-off method of changing from the reserve method of section 585.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 26 Internal Revenue 7 2011-04-01 2009-04-01 true Elective cut-off method of changing from the... § 1.585-7 Elective cut-off method of changing from the reserve method of section 585. (a) General rule...)) may elect to use the cut-off method set forth in this section. Any such election must be made at the...
Systematic review of the evidence for Trails B cut-off scores in assessing fitness-to-drive.

PubMed

Roy, Mononita; Molnar, Frank

2013-01-01

Fitness-to-drive guidelines recommend employing the Trail Making B Test (a.k.a. Trails B), but do not provide guidance regarding cut-off scores. There is ongoing debate regarding the optimal cut-off score on the Trails B test. The objective of this study was to address this controversy by systematically reviewing the evidence for specific Trails B cut-off scores (e.g., cut-offs in both time to completion and number of errors) with respect to fitness-to-drive. Systematic review of all prospective cohort, retrospective cohort, case-control, correlation, and cross-sectional studies reporting the ability of the Trails B to predict driving safety that were published in English-language, peer-reviewed journals. Forty-seven articles were reviewed. None of the articles justified sample sizes via formal calculations. Cut-off scores reported based on research include: 90 seconds, 133 seconds, 147 seconds, 180 seconds, and < 3 errors. There is support for the previously published Trails B cut-offs of 3 minutes or 3 errors (the '3 or 3 rule'). Major methodological limitations of this body of research were uncovered including (1) lack of justification of sample size leaving studies open to Type II error (i.e., false negative findings), and (2) excessive focus on associations rather than clinically useful cut-off scores.
Characteristics of Helical Flow through Neck Cutoffs

NASA Astrophysics Data System (ADS)

Richards, D.; Konsoer, K. M.; Turnipseed, C.; Willson, C. S.

2017-12-01

Meander cutoffs and oxbows lakes are a ubiquitous feature of riverine landscapes yet there is a paucity of detailed investigations concentrated on the three-dimensional flow structure through evolving neck cutoffs. The purpose of this research is to investigate and characterize helical flow through neck cutoffs with two different planform configurations: elongate meander loops and serpentine loops. Three-dimensional velocity measurements was collected with an acoustic Doppler current profiler for five cutoffs on the White River, Arkansas. Pronounced helical flow was found through all elongate loop cutoff sites, formed from the balance between centrifugal force resulting from the curving of flow through the cutoff channel and pressure gradient force resulting from water surface super-elevation between primary flow and flow at the entrance and exit of the abandoned loop. The sense of motion of the helical flow caused near-surface fluid to travel outward toward the abandoned loop while near-bed fluid was redirected toward the downstream channel. Another characteristic of the helical flow structure for elongate loop cutoffs was the reversal of helical flow over a relatively short distance, causing patterns of secondary circulation that differed from typical patterns observed through curved channels with point bars. Lastly, helical flow was revealed within zones of strong flow recirculation, enhanced by an exchange of streamwise momentum between shear layers.
Are lower TSH cutoffs in neonatal screening for congenital hypothyroidism warranted?

PubMed Central

Lain, Samantha; Trumpff, Caroline; Grosse, Scott D; Olivieri, Antonella; Van Vliet, Guy

2018-01-01

When newborn screening (NBS) for congenital hypothyroidism (CH) using thyroid-stimulating hormone (TSH) as a primary screening test was introduced, typical TSH screening cutoffs were 20–50 U/L of whole blood. Over the years, lowering of TSH cutoffs has contributed to an increased prevalence of detected CH. However, a consensus on the benefit deriving from lowering TSH cutoffs at screening is lacking. The present paper outlines arguments both for and against the lowering of TSH cutoffs at NBS. It includes a review of recently published evidence from Australia, Belgium and Italy. A section focused on economic implications of lowering TSH cutoffs is also provided. One issue that bears further examination is the extent to which mild iodine deficiency at the population level might affect the association of neonatal TSH values with cognitive and developmental outcomes. A debate on TSH cutoffs provides the opportunity to reflect on how to make NBS for CH more effective and to guarantee optimum neurocognitive development and a good quality of life to babies with mild as well as with severe CH. All authors of this debate article agree on the need to establish optimal TSH cutoffs for screening programs in various settings and to ensure the benefits of screening and access to care for newborns worldwide. PMID:28694389
A Simulation Study of Categorizing Continuous Exposure Variables Measured with Error in Autism Research: Small Changes with Large Effects.

PubMed

Heavner, Karyn; Burstyn, Igor

2015-08-24

Variation in the odds ratio (OR) resulting from selection of cutoffs for categorizing continuous variables is rarely discussed. We present results for the effect of varying cutoffs used to categorize a mismeasured exposure in a simulated population in the context of autism spectrum disorders research. Simulated cohorts were created with three distinct exposure-outcome curves and three measurement error variances for the exposure. ORs were calculated using logistic regression for 61 cutoffs (mean ± 3 standard deviations) used to dichotomize the observed exposure. ORs were calculated for five categories with a wide range for the cutoffs. For each scenario and cutoff, the OR, sensitivity, and specificity were calculated. The three exposure-outcome relationships had distinctly shaped OR (versus cutoff) curves, but increasing measurement error obscured the shape. At extreme cutoffs, there was non-monotonic oscillation in the ORs that cannot be attributed to "small numbers." Exposure misclassification following categorization of the mismeasured exposure was differential, as predicted by theory. Sensitivity was higher among cases and specificity among controls. Cutoffs chosen for categorizing continuous variables can have profound effects on study results. When measurement error is not too great, the shape of the OR curve may provide insight into the true shape of the exposure-disease relationship.
Azimuth cut-off model for significant wave height investigation along coastal water of Kuala Terengganu, Malaysia

NASA Astrophysics Data System (ADS)

Marghany, Maged; Ibrahim, Zelina; Van Genderen, Johan

2002-11-01

The present work is used to operationalize the azimuth cut-off concept in the study of significant wave height. Three ERS-1 images have been used along the coastal waters of Terengganu, Malaysia. The quasi-linear transform was applied to map the SAR wave spectra into real ocean wave spectra. The azimuth cut-off was then used to model the significant wave height. The results show that azimuth cut-off varied with the different period of the ERS-1 images. This is because of the fact that the azimuth cut-off is a function of wind speed and significant wave height. It is of interest to find that the significant wave height modeled from azimuth cut-off is in good relation with ground wave conditions. It can be concluded that ERS-1 can be used as a monitoring tool in detecting the significant wave height variation. The azimuth cut-off can be used to model the significant wave height. This means that the quasi-linear transform could be a good application to significant wave height variation during different seasons.
NuSTAR constraints on coronal cutoffs in Swift-BAT selected Seyfert 1 AGN

NASA Astrophysics Data System (ADS)

Kamraj, Nikita; Harrison, Fiona; Balokovic, Mislav; Brightman, Murray; Stern, Daniel

2017-08-01

The continuum X-ray emission from Active Galactic Nuclei (AGN) is believed to originate in a hot, compact corona above the accretion disk. Compton upscattering of UV photons from the inner accretion disk by coronal electrons produces a power law X-ray continuum with a cutoff at energies determined by the electron temperature. The NuSTAR observatory, with its high sensitivity in hard X-rays, has enabled detailed broadband modeling of the X-ray spectra of AGN, thereby allowing tight constraints to be placed on the high-energy cutoff of the X-ray continuum. Recent detections of low cutoff energies in Seyfert 1 AGN in the NuSTAR band have motivated us to pursue a systematic search for low cutoff candidates in Swift-BAT detected Seyfert 1 AGN that have been observed with NuSTAR. We use our constraints on the cutoff energy to map out the location of these sources on the compactness - temperature diagram for AGN coronae, and discuss the implications of low cutoff energies for the cooling and thermalization mechanisms in the corona.
Control of atomic transition rates via laser-light shaping

NASA Astrophysics Data System (ADS)

Jáuregui, R.

2015-04-01

A modular systematic analysis of the feasibility of modifying atomic transition rates by tailoring the electromagnetic field of an external coherent light source is presented. The formalism considers both the center of mass and internal degrees of freedom of the atom, and all properties of the field: frequency, angular spectrum, and polarization. General features of recoil effects for internal forbidden transitions are discussed. A comparative analysis of different structured light sources is explicitly worked out. It includes spherical waves, Gaussian beams, Laguerre-Gaussian beams, and propagation invariant beams with closed analytical expressions. It is shown that increments in the order of magnitude of the transition rates for Gaussian and Laguerre-Gaussian beams, with respect to those obtained in the paraxial limit, require waists of the order of the wavelength, while propagation invariant modes may considerably enhance transition rates under more favorable conditions. For transitions that can be naturally described as modifications of the atomic angular momentum, this enhancement is maximal (within propagation invariant beams) for Bessel modes, Mathieu modes can be used to entangle the internal and center-of-mass involved states, and Weber beams suppress this kind of transition unless they have a significant component of odd modes. However, if a recoil effect of the transition with an adequate symmetry is allowed, the global transition rate (center of mass and internal motion) can also be enhanced using Weber modes. The global analysis presented reinforces the idea that a better control of the transitions between internal atomic states requires both a proper control of the available states of the atomic center of mass, and shaping of the background electromagnetic field.
Global numerical simulations of the rise of vortex-mediated pulsar glitches in full general relativity

NASA Astrophysics Data System (ADS)

Sourie, A.; Chamel, N.; Novak, J.; Oertel, M.

2017-02-01

In this paper, we study in detail the role of general relativity on the global dynamics of giant pulsar glitches as exemplified by Vela. For this purpose, we carry out numerical simulations of the spin up triggered by the sudden unpinning of superfluid vortices. In particular, we compute the exchange of angular momentum between the core neutron superfluid and the rest of the star within a two-fluid model including both (non-dissipative) entrainment effects and (dissipative) mutual friction forces. Our simulations are based on a quasi-stationary approach using realistic equations of state (EoSs). We show that the evolution of the angular velocities of both fluids can be accurately described by an exponential law. The associated characteristic rise time τr, which can be precisely computed from stationary configurations only, has a form similar to that obtained in the Newtonian limit. However, general relativity changes the structure of the star and leads to additional couplings between the fluids due to frame-dragging effects. As a consequence, general relativity can have a large impact on the actual value of τr: the errors incurred by using Newtonian gravity are thus found to be as large as ˜40 per cent for the models considered. Values of the rise time are calculated for Vela and compared with current observational limits. Finally, we study the amount of gravitational waves emitted during a glitch. Simple expressions are obtained for the corresponding characteristic amplitudes and frequencies. The detectability of glitches through gravitational wave observatories is briefly discussed.
Consequences of high effective Prandtl number on solar differential rotation and convective velocity

NASA Astrophysics Data System (ADS)

Karak, Bidya Binay; Miesch, Mark; Bekki, Yuto

2018-04-01

Observations suggest that the large-scale convective velocities obtained by solar convection simulations might be over-estimated (convective conundrum). One plausible solution to this could be the small-scale dynamo which cannot be fully resolved by global simulations. The small-scale Lorentz force suppresses the convective motions and also the turbulent mixing of entropy between upflows and downflows, leading to a large effective Prandtl number (Pr). We explore this idea in three-dimensional global rotating convection simulations at different thermal conductivity (κ), i.e., at different Pr. In agreement with previous non-rotating simulations, the convective velocity is reduced with the increase of Pr as long as the thermal conductive flux is negligible. A subadiabatic layer is formed near the base of the convection zone due to continuous deposition of low entropy plumes in low-κ simulations. The most interesting result of our low-κ simulations is that the convective motions are accompanied by a change in the convection structure that is increasingly influenced by small-scale plumes. These plumes tend to transport angular momentum radially inward and thus establish an anti-solar differential rotation, in striking contrast to the solar rotation profile. If such low diffusive plumes, driven by the radiative-surface cooling, are present in the Sun, then our results cast doubt on the idea that a high effective Pr may be a viable solution to the solar convective conundrum. Our study also emphasizes that any resolution of the conundrum that relies on the downward plumes must take into account the angular momentum transport and heat transport.
In vitro validation and reliability study of electromagnetic skin sensors for evaluation of end range of motion positions of the hip.

PubMed

Audenaert, E A; Vigneron, L; Van Hoof, T; D'Herde, K; van Maele, G; Oosterlinck, D; Pattyn, C

2011-12-01

There is growing evidence that femoroacetabular impingement (FAI) is a probable risk factor for the development of early osteoarthritis in the nondysplastic hip. As FAI arises with end range of motion activities, measurement errors related to skin movement might be higher than anticipated when using previously reported methods for kinematic evaluation of the hip. We performed an in vitro validation and reliability study of a noninvasive method to define pelvic and femur positions in end range of motion activities of the hip using an electromagnetic tracking device. Motion data, collected from sensors attached to the bone and skin of 11 cadaver hips, were simultaneously obtained and compared in a global reference frame. Motion data were then transposed in the hip joint local coordinate systems. Observer-related variability in locating the anatomical landmarks required to define the local coordinate system and variability of determining the hip joint center was evaluated. Angular root mean square (RMS) differences between the bony and skin sensors averaged 3.2° (SD 3.5°) and 1.8° (SD 2.3°) in the global reference frame for the femur and pelvic sensors, respectively. Angular RMS differences between the bony and skin sensors in the hip joint local coordinate systems ranged at end range of motion and dependent on the motion under investigation from 1.91 to 5.81°. The presented protocol for evaluation of hip motion seems to be suited for the 3-D description of motion relevant to the experimental and clinical evaluation of femoroacetabular impingement.

Alterations of brain network hubs in reflex syncope: Evidence from a graph theoretical analysis based on DTI.

PubMed

Park, Bong Soo; Lee, Yoo Jin; Park, Jin-Han; Kim, Il Hwan; Park, Si Hyung; Lee, Ho-Joon; Park, Kang Min

2018-06-01

We evaluated global topology and organization of regional hubs in the brain networks and microstructural abnormalities in the white matter of patients with reflex syncope. Twenty patients with reflex syncope and thirty healthy subjects were recruited, and they underwent diffusion tensor imaging (DTI) scans. Graph theory was applied to obtain network measures based on extracted DTI data, using DSI Studio. We then investigated differences in the network measures between the patients with reflex syncope and the healthy subjects. We also analyzed microstructural abnormalities of white matter using tract-based spatial statistics analysis (TBSS). Measures of global topology were not different between patients with reflex syncope and healthy subjects. However, in reflex syncope patients, the strength measures of the right angular, left inferior frontal, left middle orbitofrontal, left superior medial frontal, and left middle temporal gyrus were lower than in healthy subjects. The betweenness centrality measures of the left middle orbitofrontal, left fusiform, and left lingual gyrus in patients were lower than those in healthy subjects. The PageRank centrality measures of the right angular, left middle orbitofrontal, and left superior medial frontal gyrus in patients were lower than those in healthy subjects. Regarding the analysis of the white matter microstructure, there were no differences in the fractional anisotropy and mean diffusivity values between the two groups. We have identified a reorganization of network hubs in the brain network of patients with reflex syncope. These alterations in brain network may play a role in the pathophysiologic mechanism underlying reflex syncope. © 2018 The Authors. Brain and Behavior published by Wiley Periodicals, Inc.
Evaluation of Life Cycle Assessment (LCA) for Roadway Drainage Systems.

PubMed

Byrne, Diana M; Grabowski, Marta K; Benitez, Amy C B; Schmidt, Arthur R; Guest, Jeremy S

2017-08-15

Roadway drainage design has traditionally focused on cost-effectively managing water quantity; however, runoff carries pollutants, posing risks to the local environment and public health. Additionally, construction and maintenance incur costs and contribute to global environmental impacts. While life cycle assessment (LCA) can potentially capture local and global environmental impacts of roadway drainage and other stormwater systems, LCA methodology must be evaluated because stormwater systems differ from wastewater and drinking water systems to which LCA is more frequently applied. To this end, this research developed a comprehensive model linking roadway drainage design parameters to LCA and life cycle costing (LCC) under uncertainty. This framework was applied to 10 highway drainage projects to evaluate LCA methodological choices by characterizing environmental and economic impacts of drainage projects and individual components (basin, bioswale, culvert, grass swale, storm sewer, and pipe underdrain). The relative impacts of drainage components varied based on functional unit choice. LCA inventory cutoff criteria evaluation showed the potential for cost-based criteria, which performed better than mass-based criteria. Finally, the local aquatic benefits of grass swales and bioswales offset global environmental impacts for four impact categories, highlighting the need to explicitly consider local impacts (i.e., direct emissions) when evaluating drainage technologies.
Spatial-frequency cutoff requirements for pattern recognition in central and peripheral vision

PubMed Central

Kwon, MiYoung; Legge, Gordon E.

2011-01-01

It is well known that object recognition requires spatial frequencies exceeding some critical cutoff value. People with central scotomas who rely on peripheral vision have substantial difficulty with reading and face recognition. Deficiencies of pattern recognition in peripheral vision, might result in higher cutoff requirements, and may contribute to the functional problems of people with central-field loss. Here we asked about differences in spatial-cutoff requirements in central and peripheral vision for letter and face recognition. The stimuli were the 26 letters of the English alphabet and 26 celebrity faces. Each image was blurred using a low-pass filter in the spatial frequency domain. Critical cutoffs (defined as the minimum low-pass filter cutoff yielding 80% accuracy) were obtained by measuring recognition accuracy as a function of cutoff (in cycles per object). Our data showed that critical cutoffs increased from central to peripheral vision by 20% for letter recognition and by 50% for face recognition. We asked whether these differences could be accounted for by central/peripheral differences in the contrast sensitivity function (CSF). We addressed this question by implementing an ideal-observer model which incorporates empirical CSF measurements and tested the model on letter and face recognition. The success of the model indicates that central/peripheral differences in the cutoff requirements for letter and face recognition can be accounted for by the information content of the stimulus limited by the shape of the human CSF, combined with a source of internal noise and followed by an optimal decision rule. PMID:21854800
Absolute Plate Velocities from Seismic Anisotropy

NASA Astrophysics Data System (ADS)

Kreemer, Corné; Zheng, Lin; Gordon, Richard

2015-04-01

The orientation of seismic anisotropy inferred beneath plate interiors may provide a means to estimate the motions of the plate relative to the sub-asthenospheric mantle. Here we analyze two global sets of shear-wave splitting data, that of Kreemer [2009] and an updated and expanded data set, to estimate plate motions and to better understand the dispersion of the data, correlations in the errors, and their relation to plate speed. We also explore the effect of using geologically current plate velocities (i.e., the MORVEL set of angular velocities [DeMets et al. 2010]) compared with geodetically current plate velocities (i.e., the GSRM v1.2 angular velocities [Kreemer et al. 2014]). We demonstrate that the errors in plate motion azimuths inferred from shear-wave splitting beneath any one tectonic plate are correlated with the errors of other azimuths from the same plate. To account for these correlations, we adopt a two-tier analysis: First, find the pole of rotation and confidence limits for each plate individually. Second, solve for the best fit to these poles while constraining relative plate angular velocities to consistency with the MORVEL relative plate angular velocities. The SKS-MORVEL absolute plate angular velocities (based on the Kreemer [2009] data set) are determined from the poles from eight plates weighted proportionally to the root-mean-square velocity of each plate. SKS-MORVEL indicates that eight plates (Amur, Antarctica, Caribbean, Eurasia, Lwandle, Somalia, Sundaland, and Yangtze) have angular velocities that differ insignificantly from zero. The net rotation of the lithosphere is 0.25±0.11° Ma-1 (95% confidence limits) right-handed about 57.1°S, 68.6°E. The within-plate dispersion of seismic anisotropy for oceanic lithosphere (σ=19.2° ) differs insignificantly from that for continental lithosphere (σ=21.6° ). The between-plate dispersion, however, is significantly smaller for oceanic lithosphere (σ=7.4° ) than for continental lithosphere (σ=14.7° ). Two of the slowest-moving plates, Antarctica (vRMS=4 mm a-1, σ=29° ) and Eurasia (vRMS=3 mm a-1, σ=33° ), have two of the largest within-plate dispersions, which may indicate that a plate must move faster than ˜5 mm a-1 to result in seismic anisotropy useful for estimating plate motion. We will investigate if these relationships still hold with the new expanded data set and with the alternative set of relative plate angular velocities. We have found systematic differences between the SKS orientations and our predicted plate motion azimuths underneath the Arabia plate, which suggests to us either plate-scale mantle flow process not directly associated with that plate's absolute motion or intrinsic lithospheric anisotropy. We will discuss more of such discrepancies underneath other plates using the enlarged data set.
Systematic review of the evidence for Trails B cut-off scores in assessing fitness-to-drive

PubMed Central

Roy, Mononita; Molnar, Frank

2013-01-01

Background Fitness-to-drive guidelines recommend employing the Trail Making B Test (a.k.a. Trails B), but do not provide guidance regarding cut-off scores. There is ongoing debate regarding the optimal cut-off score on the Trails B test. The objective of this study was to address this controversy by systematically reviewing the evidence for specific Trails B cut-off scores (e.g., cut-offs in both time to completion and number of errors) with respect to fitness-to-drive. Methods Systematic review of all prospective cohort, retrospective cohort, case-control, correlation, and cross-sectional studies reporting the ability of the Trails B to predict driving safety that were published in English-language, peer-reviewed journals. Results Forty-seven articles were reviewed. None of the articles justified sample sizes via formal calculations. Cut-off scores reported based on research include: 90 seconds, 133 seconds, 147 seconds, 180 seconds, and < 3 errors. Conclusions There is support for the previously published Trails B cut-offs of 3 minutes or 3 errors (the ‘3 or 3 rule’). Major methodological limitations of this body of research were uncovered including (1) lack of justification of sample size leaving studies open to Type II error (i.e., false negative findings), and (2) excessive focus on associations rather than clinically useful cut-off scores. PMID:23983828
Concurrence of the strengths and difficulties questionnaire and developmental behaviour checklist among children with an intellectual disability.

PubMed

Rice, L J; Emerson, E; Gray, K M; Howlin, P; Tonge, B J; Warner, G L; Einfeld, S L

2018-02-01

The Strengths and Difficulties Questionnaire (SDQ) is widely used to measure emotional and behavioural problems in typically developing young people, although there is some evidence that it may also be suitable for children with intellectual disability (ID). The Developmental Behaviour Checklist - Parent version (DBC-P) is a measure of emotional and behavioural problems that was specifically designed for children and adolescents with an ID. The DBC-P cut-off has high agreement with clinical diagnosis. The aim of this study was to estimate the relationship between DBC-P and SDQ scores in a sample of children with ID. Parents of 83 young people with ID aged 4-17 years completed the parent versions of the SDQ and the DBC-P. We evaluated the concurrent validity of the SDQ and DBC-P total scores, and the agreement between the DBC-P cut-off and the SDQ cut-offs for 'borderline' and 'abnormal' behaviour. The SDQ total difficulties score correlated well with the DBC-P total behaviour problem score. Agreement between the SDQ borderline cut-off and the DBC-P cut-off for abnormality was high (83%), but was lower for the SDQ abnormal cut-off (75%). Positive agreement between the DBC-P and the SDQ borderline cut-off was also high, with the SDQ borderline cut-off identifying 86% of those who met the DBC-P criterion. Negative agreement was weaker, with the SDQ borderline cut-off identifying only 79% of the participants who did not meet the DBC-P cut-off. The SDQ borderline cut-off has some validity as a measure of overall levels of behavioural and emotional problems in young people with ID, and may be useful in epidemiological studies that include participants with and without ID. However, where it is important to focus on behavioural profiles in children with ID, a specialised ID instrument with established psychometric properties, such as the DBC-P, may provide more reliable and valid information. © 2017 MENCAP and International Association of the Scientific Study of Intellectual and Developmental Disabilities and John Wiley & Sons Ltd.
Percentage of body fat cutoffs by sex, age, and race-ethnicity in the US adult population from NHANES 1999-2004.

PubMed

Heo, Moonseong; Faith, Myles S; Pietrobelli, Angelo; Heymsfield, Steven B

2012-03-01

To date, there is no consensus regarding adult cutoffs of percentage of body fat or estimated cutoffs on the basis of nationally representative samples with rigorous body-composition measurements. We developed cutoffs of percentage of body fat on the basis of the relation between dual-energy x-ray absorptiometry-measured fat mass and BMI (in kg/m(2)) stratified by sex, age, and race-ethnicity by using 1999-2004 NHANES data. A simple regression (percentage of body fat = β(0) + β(1) × 1 ÷ BMI) was fit for each combination of sex (men and women), 3 age groups (18-29, 30-49, and 50-84 y of age), and 3 race-ethnicity groups (non-Hispanic whites, non-Hispanic blacks, and Mexican Americans). Model fitting included a consideration of complex survey design and multiple imputations. Cutoffs of percentage of body fat were computed that corresponded to BMI cutoffs of 18.5, 25, 30, 35, and 40 on the basis of estimated prediction equations. R(2) ranged from 0.54 to 0.72 for men (n = 6544) and 0.58 to 0.79 for women (n = 6362). In men, the percentage of body fat that corresponded to a BMI of 18.5, 25, 30, 35, and 40 across age and racial-ethnic groups ranged from 12.2% to 19.0%, 22.6% to 28.0%, 27.5% to 32.3%, 31.0% to 35.3%, and 33.6% to 37.6%, respectively; the corresponding ranges in women were from 24.6% to 32.3%, 35.0% to 40.2%, 39.9% to 44.1%, 43.4% to 47.1%, and 46.1% to 49.4%, respectively. The oldest age group had the highest cutoffs of percentage of body fat. Non-Hispanic blacks had the lowest cutoffs of percentage of body fat. Cutoffs of percentage of body fat were higher in women than in men. Cutoffs of percentage of body fat that correspond to the current US BMI cutoffs are a function of sex, age, and race-ethnicity. These factors should be taken into account when considering the appropriateness of levels of percentage of body fat.
Optimization and validation of CEDIA drugs of abuse immunoassay tests in serum on Hitachi 912.

PubMed

Kirschbaum, Katrin M; Musshoff, Frank; Schmithausen, Ricarda; Stockhausen, Sarah; Madea, Burkhard

2011-10-10

Due to sensitive limits of detection of chromatographic methods and low limit values regarding the screening of drugs under the terms of impairment in safe driving (§ 24a StVG, Street Traffic Law in Germany), preliminary immunoassay (IA) tests should be able to detect also low concentrations of legal and illegal drugs in serum in forensic cases. False-negatives should be avoided, the rate of false-positive samples should be low due to cost and time. An optimization of IA cutoff values and a validation of the assay is required for each laboratory. In a retrospective study results for serum samples containing amphetamine, methylenedioxy derivatives, cannabinoids, benzodiazepines, cocaine (metabolites), methadone and opiates obtained with CEDIA drugs of abuse reagents on a Hitachi 912 autoanalyzer were compared with quantitative results of chromatographic methods (gas or liquid chromatography coupled with mass spectrometry (GC/MS or LC/MS)). Firstly sensitivity, specificity, positive and negative predictive values and overall misclassification rates were evaluated by contingency tables and compared to ROC-analyses and Youden-Indices. Secondly ideal cutoffs were statistically calculated on the basis of sensitivity and specificity as decisive statistical criteria with focus on a high sensitivity (low rates of false-negatives), i.e. using the Youden-Index. Immunoassay (IA) and confirmatory results were available for 3014 blood samples. Sensitivity was 90% or more for nearly all analytes: amphetamines (IA cutoff 9.5 ng/ml), methylenedioxy derivatives (IA cutoff 5.5 ng/ml), cannabinoids (IA cutoff 14.5 ng/ml), benzodiazepines (IA cutoff >0 ng/ml). Test of opiates showed a sensitivity of 86% for a IA cutoff value of >0 ng/ml. Values for specificity ranged between 33% (methadone, IA cutoff 10 ng/ml) and 90% (cocaine, IA cutoff 20 ng/ml). Lower cutoff values as recommended by ROC analyses were chosen for most tests to decrease the rate of false-negatives. Analyses enabled the definition of cutoff values with good values for sensitivity. Small rates of false-positives can be accepted in forensic cases. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.
Optimal cutoff values of allergen-specific immunoglobulin E to house dust mites and animal dander based on skin-prick test results: Analysis in 16,209 patients with allergic rhinitis.

PubMed

2017-10-25

The most common tests for allergen sensitization in patients with allergic rhinitis are the skin-prick test(SPT) and an in vitro test to detect serum specific immunoglobulin E (sIgE). However, in vitro allergen test results were interpreted dichotomically as positive or negative at a threshold of 0.35kU/L of sIgE, regardless of the patient characteristics or antigen types. The purpose of this study was to determine the cutoff value for sIgE in house-dust mites and animal dander, and to analyze differences in cutoff value according to age and gender. A total of 16,209 patients with more than one allergic rhinitis symptom who underwent both SPT and serum sIgE testing were retrospectively evaluated between March 2008 and May 2012. There were 9374 male (57.8%) and 6835 female (42.2%) patients. The mean age was 31.8 years (range, 2-89 years). The criterion standard for allergen sensitization was defined as a wheal of > 3 mm or an allergen-to-histamine ratio of greater than or equal to 1 in SPT results. The Youden index was used to calculate the cutoff value of sIgE. Cutoff values of sIgE for Dermatophagoides pteronyssinus, Dermatophagoides farinae, cat, and dog were 0.69, 1.16, 0.13, and 0.45 kU/L, respectively. The cutoff value of sIgE changed according to age for D. pteronyssinus and D. farinae but not for cat and dog allergens. When categorizingaccording to age group, the cutoff values of sIgE for D. pteronyssinus and D. farinae had a tendency to decrease with age. There was no significant difference in cutoff value according to gender. The cutoff value for sIgE differed for each antigen and changed with age. Physicians should select the proper cutoff value for sIgE for appropriate criteria according to antigen and patient age rather than using a uniform cutoff value.
Optimal cutoff values of allergen-specific immunoglobulin E to house dust mites and animal dander based on skin-prick test results: Analysis in 16,209 patients with allergic rhinitis.

PubMed

Hong, Sang Duk; Ryu, Gwanghui; Seo, Min Young; Jeong, Jong In; Kim, Hyo Yeol; Chung, Seung-Kyu; Dhong, Hun-Jong

2018-01-25

The most common tests for allergen sensitization in patients with allergic rhinitis are the skin-prick test (SPT) and an in vitro test to detect serum specific immunoglobulin E (sIgE). However, in vitro allergen test results were interpreted dichotomically as positive or negative at a threshold of 0.35 kU/L of sIgE, regardless of the patient characteristics or antigen types. The purpose of this study was to determine the cutoff value for sIgE in house-dust mites and animal dander, and to analyze differences in cutoff value according to age and gender. A total of 16,209 patients with more than one allergic rhinitis symptom who underwent both SPT and serum sIgE testing were retrospectively evaluated between March 2008 and May 2012. There were 9374 male (57.8%) and 6835 female (42.2%) patients. The mean age was 31.8 years (range, 2-89 years). The criterion standard for allergen sensitization was defined as a wheal of >3 mm or an allergen-to-histamine ratio of ≥1 in SPT results. The Youden index was used to calculate the cutoff value of sIgE. Cutoff values of sIgE for Dermatophagoides pteronyssinus, Dermatophagoides farinae, cat, and dog were 0.69, 1.16, 0.13, and 0.45 kU/L, respectively. The cutoff value of sIgE changed according to age for D. pteronyssinus and D. farinae but not for cat and dog allergens. When categorizing according to age group, the cutoff values of sIgE for D. pteronyssinus and D. farinae had a tendency to decrease with age. There was no significant difference in cutoff value according to gender. The cutoff value for sIgE differed for each antigen and changed with age. Physicians should select the proper cutoff value for sIgE for appropriate criteria according to antigen and patient age rather than using a uniform cutoff value.
Field programmable analog array based on current differencing transconductance amplifiers and its application to high-order filter

NASA Astrophysics Data System (ADS)

He, Haizhen; Luo, Rongming; Hu, Zhenhua; Wen, Lei

2017-07-01

A current-mode field programmable analog array(FPAA) is presented in this paper. The proposed FPAA consists of 9 configurable analog blocks(CABs) which are based on current differencing transconductance amplifiers (CDTA) and trans-impedance amplifier (TIA). The proposed CABs interconnect through global lines. These global lines contain some bridge switches, which used to reduce the parasitic capacitance effectively. High-order current-mode low-pass and band-pass filter with transmission zeros based on the simulation of general passive RLC ladder prototypes is proposed and mapped into the FPAA structure in order to demonstrate the versatility of the FPAA. These filters exhibit good performance on bandwidth. Filter's cutoff frequency can be tuned from 1.2MHz to 40MHz.The proposed FPAA is simulated in a standard Charted 0.18μm CMOS process with +/-1.2V power supply to confirm the presented theory, and the results have good agreement with the theoretical analysis.
Psychometric properties of the Florence CyberBullying-CyberVictimization Scales.

PubMed

Palladino, Benedetta Emanuela; Nocentini, Annalaura; Menesini, Ersilia

2015-02-01

The present study tried to answer the research need for empirically validated and theoretically based instruments to assess cyberbullying and cybervictimization. The psychometric properties of the Florence CyberBullying-CyberVictimization Scales (FCBVSs) were analyzed in a sample of 1,142 adolescents (Mage=15.18 years; SD=1.12 years; 54.5% male). For both cybervictimization and cyberbullying, results support a gender invariant model involving 14 items and four factors covering four types of behaviors (written-verbal, visual, impersonation, and exclusion). The second-order confirmatory factor analysis confirmed that a "global," second-order measure of cyberbullying and cybervictimization fits the data well. Overall, the scales showed good validity (construct, concurrent, and convergent) and reliability (internal consistency and test-retest). In addition, using the global key question measure as a criterion, ROC analyses, determining the ability of a test to discriminate between groups, allowed us to identify cutoff points to classify respondents as involved/not involved starting from the continuum measure derived from the scales.
Downscaling ocean conditions with application to the Gulf of Maine, Scotian Shelf and adjacent deep ocean

NASA Astrophysics Data System (ADS)

Katavouta, Anna; Thompson, Keith R.

2016-08-01

The overall goal is to downscale ocean conditions predicted by an existing global prediction system and evaluate the results using observations from the Gulf of Maine, Scotian Shelf and adjacent deep ocean. The first step is to develop a one-way nested regional model and evaluate its predictions using observations from multiple sources including satellite-borne sensors of surface temperature and sea level, CTDs, Argo floats and moored current meters. It is shown that the regional model predicts more realistic fields than the global system on the shelf because it has higher resolution and includes tides that are absent from the global system. However, in deep water the regional model misplaces deep ocean eddies and meanders associated with the Gulf Stream. This is not because the regional model's dynamics are flawed but rather is the result of internally generated variability in deep water that leads to decoupling of the regional model from the global system. To overcome this problem, the next step is to spectrally nudge the regional model to the large scales (length scales > 90 km) of the global system. It is shown this leads to more realistic predictions off the shelf. Wavenumber spectra show that even though spectral nudging constrains the large scales, it does not suppress the variability on small scales; on the contrary, it favours the formation of eddies with length scales below the cutoff wavelength of the spectral nudging.
Transesophageal Echocardiography, 3-Dimensional and Speckle Tracking Together as Sensitive Markers for Early Outcome in Patients With Left Ventricular Dysfunction Undergoing Cardiac Surgery.

PubMed

Kumar, Alok; Puri, Goverdhan Dutt; Bahl, Ajay

2017-10-01

Speckle tracking, when combined with 3-dimensional (3D) left ventricular ejection fraction, might prove to be a more sensitive marker for postoperative ventricular dysfunction. This study investigated early outcomes in a cohort of patients with left ventricular dysfunction undergoing cardiac surgery. Prospective, blinded, observational study. University hospital; single institution. The study comprised 73 adult patients with left ventricular ejection fraction <50% undergoing cardiac surgery using cardiopulmonary bypass. Routine transesophageal echocardiography before and after bypass. Global longitudinal strain using speckle tracking and 3D left ventricular ejection fraction were computed using transesophageal echocardiography. Mean prebypass global longitudinal strain and 3D left ventricle ejection fraction were significantly lower in patients with postoperative low-cardiac-output syndrome compared with patients who did not develop low cardiac output (global longitudinal strain -7.5% v -10.7% and 3D left ventricular ejection fraction 29% v 39%, respectively; p < 0.0001). The cut-off value of global longitudinal strain predicting postoperative low-cardiac-output syndrome was -6%, with 95% sensitivity and 68% specificity; and 3D left ventricular ejection fraction was 19% with 98% sensitivity and 81% specificity. Preoperative left ventricular global longitudinal strain (-6%) and 3D left ventricular ejection fraction (19%) together could act as predictor of postoperative low-cardiac-output states with high sensitivity (99.9%) in patients undergoing cardiac surgery. Copyright © 2017 Elsevier Inc. All rights reserved.
Role of Three-Dimensional Speckle Tracking Echocardiography in the Quantification of Myocardial Iron Overload in Patients with Beta-Thalassemia Major.

PubMed

Li, Shu-Juan; Hwang, Yu-Yan; Ha, Shau-Yin; Chan, Godfrey C F; Mok, Amanda S P; Wong, Sophia J; Cheung, Yiu-Fai

2016-09-01

The new three-dimensional speckle tracking echocardiography (3DSTE) may enable comprehensive quantification of global left ventricular (LV) myocardial mechanics. Twenty-four patients aged 29.3 ± 5.2 years and 22 controls were studied. 3DSTE was performed to assess LV 3D global strain, twist and torsion, ejection fraction, and systolic dyssynchrony index (SDI). The LV SDI was calculated as % of SD of times-to-peak strain of 16 segments/RR interval. The global performance index (GPI) was calculated as (global 3D strain·torsion)/SDI. Area under the receiver operating characteristic curve (AUC) was calculated to determine the capability of 3DSTE parameters to discriminate between patients with (cardiac magnetic resonance T2* <20 ms) and those without myocardial iron overload. Compared with controls, patients had significantly lower LV global 3D strain (P < 0.001), twist (P = 0.01), torsion (P = 0.04), and ejection fraction (P < 0.001) and greater SDI (P < 0.001). The GPI was lower in patients than controls (P < 0.001). T2* value correlated positively with global 3D strain (r = 0.74, P < 0.001) and GPI (r = 0.63, P = 0.001), and negatively with SDI (r = -0.44, P = 0.03). The AUCs of GPI, global 3D strain, ejection fraction, torsion, and 1/SDI were 0.94, 0.90, 0.87, 0.82, and 0.70, respectively. The GPI cutoff of 2.7°/cm had a sensitivity of 94.9% and a specificity of 88.9% of differentiating patients with from those without myocardial iron overload. The LV composite index of strain, torsion, and dyssynchrony derived from 3DSTE enables sensitive detection of myocardial iron overload in patients with thalassemia. © 2016, Wiley Periodicals, Inc.
Comparative analysis of anthropometric indices of obesity as correlates and potential predictors of risk for hypertension and prehypertension in a population in Nigeria.

PubMed

Ononamadu, Chimaobi James; Ezekwesili, Chinwe Nonyelum; Onyeukwu, Onyemaechi Faith; Umeoguaju, Uchenna Francis; Ezeigwe, Obiajulu Christian; Ihegboro, Godwin Okwudiri

Obesity is a well-established independent risk factor for hypertension and other cardiometabolic disorders. However, the best anthropometric index of obesity that predicts or associates strongly with hypertension and related conditions remains controversial and inconclusive. This study compared the performance of eight anthropometric indices of obesity: body mass index (BMI), ponderal index (PI), waist circumference (WC), hip circumference (HC), waist-hip ratio (WHR), waist-height ratio (WHtR), body adiposity index (BAI) and conicity index (CI) as correlates and potential predictors of risk of hypertension and prehypertension in a Nigerian population, and also the possible effect of combining two or more indices in that regard. This church-based, cross-sectional study was conducted in Anambra state, south-eastern Nigeria from 2012 to 2013. A total of 912 persons (436 male and 476 female) drawn randomly from three major cities (Awka, Onitsha and Nnewi) in the state participated in the study. Information on demography, medical history and lifestyle were obtained using a well-structured and validated questionnaire. The systolic/diastolic blood pressure and anthropometric measurements were taken by well-trained personnel. The resulting data were analysed using descriptive statistics, logistic regression, Poisson regression and receiver operating characteristic curve analysis. The mean values of all the anthropometric indices studied increased from normotension, through prehypertension to hypertension in both genders. BMI, WC, HC and CI were significantly higher (p < 0.05) in females than males. All the anthropometric indices studied were significantly (p < 0.001 except for CI) correlated with systolic and diastolic blood pressure. BMI, WHtR, WC and PI (with higher correlation coefficients for blood pressure) showed the best potential to predict hypertension and prehypertension in the study: BMI (cut-off = 24.49, AUC = 0.698; cut-off = 23.62, AUC = 0.659), WHtR (cut-off = 0.55, AUC = 0.682; cut-off = 0.5, AUC = 0.636), WC (cut-off = 91.44, AUC = 0.692; cut-off = 82.55, AUC = 0.645), PI (cut-off = 14.45, AUC = 0.670; cut-off = 13.69, AUC = 0.639), in males; and BMI (cut-off = 24.44, AUC = 0.622; cut-off = 28.01, AUC = 0.609), WHtR (cut-off = 0.51, AUC = 0.624; cut-off = 0.6, AUC = 0.572), WC ( cut-off = 96.62, AUC = 0.616; cut-off = 96.52, AUC = 0.584), PI ( cut-off = 16.38, AUC = 0.619; cut-off = 17.65, AUC = 0.599), in females for hypertension and prehypertension, respectively. In predicting hypertension risk, WC and WHtR did not significantly improve the performance of BMI in the models when included using our decision rule. Overall, CI had a very poor discriminatory power for both conditions in this study. BMI, WHtR, WC and PI emerged the best predictors of hypertension risk, and BMI, WC and PI of prehypertension risk in this study. The combination of high-performing anthropometric indices in a model did not improve their performance. Therefore we recommend the simultaneous but independent use of BMI and either WC or WHtR for predicting hypertension, and BMI and WC for prehypertension risk, bearing in mind that both types of index (abdominal and general obesity) account for different forms of obesity.
Comparative analysis of anthropometric indices of obesity as correlates and potential predictors of risk for hypertension and prehypertension in a population in Nigeria

PubMed Central

Ononamadu, Chimaobi James; Ihegboro, Godwin Okwudiri; Ezekwesili, Chinwe Nonyelum; Onyeukwu, Onyemaechi Faith; Umeoguaju,, Uchenna Francis; Ezeigwe, Obiajulu Christian

2017-01-01

Summary Background: Obesity is a well-established independent risk factor for hypertension and other cardiometabolic disorders. However, the best anthropometric index of obesity that predicts or associates strongly with hypertension and related conditions remains controversial and inconclusive. Objective: This study compared the performance of eight anthropometric indices of obesity: body mass index (BMI), ponderal index (PI), waist circumference (WC), hip circumference (HC), waist–hip ratio (WHR), waist–height ratio (WHtR), body adiposity index (BAI) and conicity index (CI) as correlates and potential predictors of risk of hypertension and prehypertension in a Nigerian population, and also the possible effect of combining two or more indices in that regard. Methods: This church-based, cross-sectional study was conducted in Anambra state, south-eastern Nigeria from 2012 to 2013. A total of 912 persons (436 male and 476 female) drawn randomly from three major cities (Awka, Onitsha and Nnewi) in the state participated in the study. Information on demography, medical history and lifestyle were obtained using a well-structured and validated questionnaire. The systolic/diastolic blood pressure and anthropometric measurements were taken by well-trained personnel. The resulting data were analysed using descriptive statistics, logistic regression, Poisson regression and receiver operating characteristic curve analysis. Results: The mean values of all the anthropometric indices studied increased from normotension, through prehypertension to hypertension in both genders. BMI, WC, HC and CI were significantly higher (p < 0.05) in females than males. All the anthropometric indices studied were significantly (p < 0.001 except for CI) correlated with systolic and diastolic blood pressure. BMI, WHtR, WC and PI (with higher correlation coefficients for blood pressure) showed the best potential potential to predict hypertension and prehypertension in the study: BMI (cut-off = 24.49, AUC = 0.698; cut-off = 23.62, AUC = 0.659), WHtR (cut-off = 0.55, AUC = 0.682; cut-off = 0.5, AUC = 0.636), WC (cut-off = 91.44, AUC = 0.692; cut-off = 82.55, AUC = 0.645), PI (cut-off = 14.45, AUC = 0.670; cut-off = 13.69, AUC = 0.639), in males; and BMI (cut-off = 24.44, AUC = 0.622; cut-off = 28.01, AUC = 0.609), WHtR (cut-off = 0.51, AUC = 0.624; cut-off = 0.6, AUC = 0.572), WC (cut-off = 96.62, AUC = 0.616; cut-off = 96.52, AUC = 0.584), PI (cut-off = 16.38, AUC = 0.619; cut-off = 17.65, AUC = 0.599), in females for hypertension and prehypertension, respectively. In predicting hypertension risk, WC and WHtR did not significantly improve the performance of BMI in the models when included using our decision rule. Overall, CI had a very poor discriminatory power for both conditions in this study. Conclusion: BMI, WHtR, WC and PI emerged the best predictors of hypertension risk, and BMI, WC and PI of prehypertension risk in this study. The combination of high-performing anthropometric indices in a model did not improve their performance. Therefore we recommend the simultaneous but independent use of BMI and either WC or WHtR for predicting hypertension, and BMI and WC for prehypertension risk, bearing in mind that both types of index (abdominal and general obesity) account for different forms of obesity. PMID:27701484
Critical analysis of forensic cut-offs and legal thresholds: A coherent approach to inference and decision.

PubMed

Biedermann, A; Taroni, F; Bozza, S; Augsburger, M; Aitken, C G G

2018-07-01

In this paper we critically discuss the definition and use of cut-off values by forensic scientists, for example in forensic toxicology, and point out when and why such values - and ensuing categorical conclusions - are inappropriate concepts for helping recipients of expert information with their questions of interest. Broadly speaking, a cut-off is a particular value of results of analyses of a target substance (e.g., a toxic substance or one of its metabolites in biological sample from a person of interest), defined in a way such as to enable scientists to suggest conclusions regarding the condition of the person of interest. The extent to which cut-offs can be reliably defined and used is not unanimously agreed within the forensic science community, though many practitioners - especially in operational laboratories - rely on cut-offs for reasons such as ease of use and simplicity. In our analysis, we challenge this practice by arguing that choices made for convenience should not be to the detriment of balance and coherence. To illustrate our discussion, we will choose the example of alcohol markers in hair, used widely by forensic toxicologists to reach conclusions regarding the drinking behaviour of individuals. Using real data from one of the co-authors' own work and recommendations of cut-offs published by relevant professional organisations, we will point out in what sense cut-offs are incompatible with current evaluative guidelines (e.g., [31]) and show how to proceed logically without cut-offs by using a standard measure for evidential value. Our conclusions run counter to much current practice, but are inevitable given the inherent definitional and conceptual shortcomings of scientific cut-offs. We will also point out the difference between scientific cut-offs and legal thresholds and argue that the latter - but not the former - are justifiable and can be dealt with in logical evaluative procedures. Copyright © 2018 Elsevier B.V. All rights reserved.
Optimal cut-off points for waist circumference in the definition of metabolic syndrome in Brazilian adults: baseline analyses of the Longitudinal Study of Adult Health (ELSA-Brasil).

PubMed

Cardinal, Thiane Ristow; Vigo, Alvaro; Duncan, Bruce Bartholow; Matos, Sheila Maria Alvim; da Fonseca, Maria de Jesus Mendes; Barreto, Sandhi Maria; Schmidt, Maria Inês

2018-01-01

Waist circumference (WC) has been incorporated in the definition of the metabolic syndrome (MetS) but the exact WC cut-off points across populations are not clear. The Joint Interim Statement (JIS) suggested possible cut-offs to different populations and ethnic groups. However, the adequacy of these cut-offs to Brazilian adults has been scarcely investigated. The objective of the study is to evaluate possible WC thresholds to be used in the definition of MetS using data from the Longitudinal Study of Adult Health (ELSA-Brasil), a multicenter cohort study of civil servants (35-74 years old) of six Brazilian cities. We analyzed baseline data from 14,893 participants (6772 men and 8121 women). A MetS was defined according to the JIS criteria, but excluding WC and thus requiring 2 of the 4 remaining elements. We used restricted cubic spline regression to graph the relationship between WC and MetS. We identified optimal cut-off points which maximized joint sensitivity and specificity (Youden's index) from Receiver Operator Characteristic Curves. We also estimated the C-statistics using logistic regression. We found no apparent threshold for WC in restricted cubic spline plots. Optimal cut-off for men was 92 cm (2 cm lower than that recommended by JIS for Caucasian/Europids or Sub-Saharan African men), but 2 cm higher than that recommended for ethnic Central and South American. For women, optimal cut-off was 86, 6 cm higher than that recommended for Caucasian/Europids and ethnic Central and South American. Optimal cut-offs did not very across age groups and most common race/color categories (except for Asian men, 87 cm). Sex-specific cut-offs for WC recommended by JIS differ from optimal cut-offs we found for adult men and women of Brazil´s most common ethnic groups.
Economic Outlook for Radiometric Selection of Ores; POSSIBILITES OUVERTES EN MATIERE ECONOMIQUE PAR SELECTION RADIOMETRIQUE DES MINERAIS

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

Formery, P.; Ziegler, V.

1959-10-31

The radiometric grading of uranium ores is analyzed. The cut-off is defined, and its parameters are derived. Cut-off above ground and underground are statistically interpreted. An evaluation is made of the combined effects of both kinds of cut-off made in succession. The corrections to be made to the radiometric apparatus used are determined. Application of the theory of cutoff to the evaluation of reserves is discussed. (J.S.R.)

End-to-end distance and contour length distribution functions of DNA helices

NASA Astrophysics Data System (ADS)

Zoli, Marco

2018-06-01

I present a computational method to evaluate the end-to-end and the contour length distribution functions of short DNA molecules described by a mesoscopic Hamiltonian. The method generates a large statistical ensemble of possible configurations for each dimer in the sequence, selects the global equilibrium twist conformation for the molecule, and determines the average base pair distances along the molecule backbone. Integrating over the base pair radial and angular fluctuations, I derive the room temperature distribution functions as a function of the sequence length. The obtained values for the most probable end-to-end distance and contour length distance, providing a measure of the global molecule size, are used to examine the DNA flexibility at short length scales. It is found that, also in molecules with less than ˜60 base pairs, coiled configurations maintain a large statistical weight and, consistently, the persistence lengths may be much smaller than in kilo-base DNA.
A Hough Transform Global Probabilistic Approach to Multiple-Subject Diffusion MRI Tractography

PubMed Central

Aganj, Iman; Lenglet, Christophe; Jahanshad, Neda; Yacoub, Essa; Harel, Noam; Thompson, Paul M.; Sapiro, Guillermo

2011-01-01

A global probabilistic fiber tracking approach based on the voting process provided by the Hough transform is introduced in this work. The proposed framework tests candidate 3D curves in the volume, assigning to each one a score computed from the diffusion images, and then selects the curves with the highest scores as the potential anatomical connections. The algorithm avoids local minima by performing an exhaustive search at the desired resolution. The technique is easily extended to multiple subjects, considering a single representative volume where the registered high-angular resolution diffusion images (HARDI) from all the subjects are non-linearly combined, thereby obtaining population-representative tracts. The tractography algorithm is run only once for the multiple subjects, and no tract alignment is necessary. We present experimental results on HARDI volumes, ranging from simulated and 1.5T physical phantoms to 7T and 4T human brain and 7T monkey brain datasets. PMID:21376655
DOE Office of Scientific and Technical Information (OSTI.GOV)

Ong, Yen Chin, E-mail: ongyenchin@sjtu.edu.cn

Recently a purportedly novel solution of the vacuum Einstein field equations was discovered: it supposedly describes an asymptotically flat twisted black hole in 4-dimensions whose exterior spacetime rotates in a peculiar manner—the frame dragging in the northern hemisphere is opposite from that of the southern hemisphere, which results in a globally vanishing angular momentum. Furthermore it was shown that the spacetime has no curvature singularity. We show that the geometry of this black hole spacetime is nevertheless not free of pathological features. In particular, it harbors a rather drastic conical singularity along the axis of rotation. In addition, there existmore » closed timelike curves due to the fact that the constant r and constant t surfaces are not globally Riemannian. In fact, none of these are that surprising since the solution is just the Taub-NUT geometry. As such, despite the original claim that the twisted black hole might have observational consequences, it cannot be.« less
Comparing Approaches to Optimize Cut-off Scores for Short Cognitive Screening Instruments in Mild Cognitive Impairment and Dementia

PubMed Central

O’Caoimh, Rónán; Gao, Yang; Svendovski, Anton; Gallagher, Paul; Eustace, Joseph; Molloy, D. William

2017-01-01

Background: Although required to improve the usability of cognitive screening instruments (CSIs), the use of cut-off scores is controversial yet poorly researched. Objective: To explore cut-off scores for two short CSIs: the Standardized Mini-Mental State Examination (SMMSE) and Quick Mild Cognitive Impairment (Qmci) screen, describing adjustments in scores for diagnosis (MCI or dementia), age (≤, >75 years), and education (<, ≥12 years), comparing two methods: the maximal accuracy approach, derived from receiver operating characteristic curves, and Youden’s Index. Methods: Pooled analysis of assessments from patients attending memory clinics in Canada between 1999–2010 : 766 with mild cognitive impairment (MCI) and 1,746 with dementia, and 875 normal controls. Results: The Qmci was more accurate than the SMMSE in differentiating controls from MCI or cognitive impairment (MCI and dementia). Employing the maximal accuracy approach, the optimal SMMSE cut-off for cognitive impairment was <28/30 (AUC 0.86, sensitivity 74%, specificity 88%) versus <63/100 for the Qmci (AUC 0.93, sensitivity 85%, specificity 85%). Using Youden’s Index, the optimal SMMSE cut-off remained <28/30 but fell slightly to <62/100 for the Qmci (sensitivity 83%, specificity 87%). The optimal cut-off for MCI was <29/30 for the SMMSE and <67/100 for the Qmci, irrespective of technique. The maximal accuracy approach generally produced higher Qmci cut-offs than Youden’s Index, both requiring adjustment for age and education. There were no clinically meaningful differences in SMMSE cut-off scores by age and education or method employed. Conclusion: Caution should be exercised selecting cut-offs as these differ by age, education, and method of derivation, with the extent of adjustment varying between CSIs. PMID:28222528
Airway hyperresponsiveness to methacholine in 7-year-old children: sensitivity and specificity for pediatric allergist-diagnosed asthma.

PubMed

Carlsten, Chris; Dimich-Ward, Helen; Ferguson, Alexander; Becker, Allan; Dybuncio, Anne; Chan-Yeung, Moira

2011-02-01

The operating characteristics of PC(20) values used as cut-offs to define airway hyperresponsiveness, as it informs the diagnosis of asthma in children, are poorly understood. We examine data from a unique cohort to inform this concern. Determine the sensitivity and specificity of incremental PC(20) cut-offs for allergist-diagnosed asthma. Airway reactivity at age 7 was assessed in children within a birth cohort at high risk for asthma; PC(20) for methacholine was determined by standard technique including interpolation. The diagnosis of asthma was considered by the pediatric allergist without knowledge of the methacholine challenge results. Sensitivity and specificity were calculated using a cross-tabulation of asthma diagnosis with incremental PC(20) cut-off values, from 1.0 to 8.0 mg/ml, and plotted as receiver operator characteristic (ROC) curves. The "optimal" cut-off was defined as that PC(20) conferring maximal value for sensitivity plus specificity while the "balanced" cut-off was defined as that PC(20) at which sensitivity and specificity were most equal. 70/348 children (20.1%) were diagnosed with asthma. The optimal and balanced PC(20) cut-offs, both for all children and for females alone, were respectively 3 mg/ml (sensitivity 80.0%, specificity 49.1%) and 2 mg/ml (sensitivity 63.1%, specificity 64.7%). For males alone, the "optimal" and "balanced" PC(20) cut-offs were both 2 mg/ml. For this cohort of 7-year olds at high risk for asthma, methacholine challenge testing using a cut-off value of PC(20) 3 mg/ml conferred the maximal sum of specificity plus sensitivity. For contexts in which higher sensitivity or specificity is desired, other cut-offs may be preferred. Copyright © 2011 Wiley-Liss, Inc.
Earthquake Scaling Relations

NASA Astrophysics Data System (ADS)

Jordan, T. H.; Boettcher, M.; Richardson, E.

2002-12-01

Using scaling relations to understand nonlinear geosystems has been an enduring theme of Don Turcotte's research. In particular, his studies of scaling in active fault systems have led to a series of insights about the underlying physics of earthquakes. This presentation will review some recent progress in developing scaling relations for several key aspects of earthquake behavior, including the inner and outer scales of dynamic fault rupture and the energetics of the rupture process. The proximate observations of mining-induced, friction-controlled events obtained from in-mine seismic networks have revealed a lower seismicity cutoff at a seismic moment Mmin near 109 Nm and a corresponding upper frequency cutoff near 200 Hz, which we interpret in terms of a critical slip distance for frictional drop of about 10-4 m. Above this cutoff, the apparent stress scales as M1/6 up to magnitudes of 4-5, consistent with other near-source studies in this magnitude range (see special session S07, this meeting). Such a relationship suggests a damage model in which apparent fracture energy scales with the stress intensity factor at the crack tip. Under the assumption of constant stress drop, this model implies an increase in rupture velocity with seismic moment, which successfully predicts the observed variation in corner frequency and maximum particle velocity. Global observations of oceanic transform faults (OTFs) allow us to investigate a situation where the outer scale of earthquake size may be controlled by dynamics (as opposed to geologic heterogeneity). The seismicity data imply that the effective area for OTF moment release, AE, depends on the thermal state of the fault but is otherwise independent of fault's average slip rate; i.e., AE ~ AT, where AT is the area above a reference isotherm. The data are consistent with β = 1/2 below an upper cutoff moment Mmax that increases with AT and yield the interesting scaling relation Amax ~ AT1/2. Taken together, the OTF relations imply that the seismic productivity for small earthquakes (frequency per unit area) should scale as AT-1/4, which we verify using seismicity catalogs based on both surface-wave and body-wave magnitude. These scaling relations place fundamental constraints on the dynamics of strike-slip faulting on the mid-ocean ridge system.
High-frequency Earth rotation variations deduced from altimetry-based ocean tides

NASA Astrophysics Data System (ADS)

Madzak, Matthias; Schindelegger, Michael; Böhm, Johannes; Bosch, Wolfgang; Hagedoorn, Jan

2016-11-01

A model of diurnal and semi-diurnal variations in Earth rotation parameters (ERP) is constructed based on altimetry-measured tidal heights from a multi-mission empirical ocean tide solution. Barotropic currents contributing to relative angular momentum changes are estimated for nine major tides in a global inversion algorithm that solves the two-dimensional momentum equations on a regular 0.5° grid with a heavily weighted continuity constraint. The influence of 19 minor tides is accounted for by linear admittance interpolation of ocean tidal angular momentum, although the assumption of smooth admittance variations with frequency appears to be a doubtful concept for semi-diurnal mass terms in particular. A validation of the newly derived model based on post-fit corrections to polar motion and universal time (Δ UT1) from the analysis of Very Long Baseline Interferometry (VLBI) observations shows a variance reduction for semi-diurnal Δ UT1 residuals that is significant at the 0.05 level with respect to the conventional ERP model. Improvements are also evident for the explicitly modeled K_1, Q_1, and K_2 tides in individual ERP components, but large residuals of more than 15 μ as remain at the principal lunar frequencies of O_1 and M_2. We attribute these shortcomings to uncertainties in the inverted relative angular momentum changes and, to a minor extent, to violation of mass conservation in the empirical ocean tide solution. Further dedicated hydrodynamic modeling efforts of these anomalous constituents are required to meet the accuracy standards of modern space geodesy.
Sequences of extremal radially excited rotating black holes.

PubMed

Blázquez-Salcedo, Jose Luis; Kunz, Jutta; Navarro-Lérida, Francisco; Radu, Eugen

2014-01-10

In the Einstein-Maxwell-Chern-Simons theory the extremal Reissner-Nordström solution is no longer the single extremal solution with vanishing angular momentum, when the Chern-Simons coupling constant reaches a critical value. Instead a whole sequence of rotating extremal J=0 solutions arises, labeled by the node number of the magnetic U(1) potential. Associated with the same near horizon solution, the mass of these radially excited extremal solutions converges to the mass of the extremal Reissner-Nordström solution. On the other hand, not all near horizon solutions are also realized as global solutions.
Geometric scalar theory of gravity beyond spherical symmetry

NASA Astrophysics Data System (ADS)

Moschella, U.; Novello, M.

2017-04-01

We construct several exact solutions for a recently proposed geometric scalar theory of gravity. We focus on a class of axisymmetric geometries and a big-bang-like geometry and discuss their Lorentzian character. The axisymmetric solutions are parametrized by an integer angular momentum l . The l =0 (spherical) case gives rise to the Schwarzschild geometry. The other solutions have naked singular surfaces. While not a priori obvious, all the solutions that we present here are globally Lorentzian. The Lorentzian signature appears to be a robust property of the disformal geometries solving the vacuum geometric scalar theory of gravity equations.
Exact solutions of the Schrödinger equation with a coulomb ring-shaped potential in the cosmic string spacetime

NASA Astrophysics Data System (ADS)

Wang, Zhi; Long, Zheng-wen; Long, Chao-yun; Teng, Jing

2015-05-01

We study the Schrödinger equation with a Coulomb ring-shaped potential in the spacetime of a cosmic string, and the solutions of the system are obtained by using the generalized parametric Nikiforov-Uvarov (NU) method. They show that the quantum dynamics of a physical system depend on the non-trivial topological features of the cosmic string spacetime and the energy levels of the considered quantum system depend explicitly on the angular deficit α which characterizes the global structure of the metric in the cosmic string spacetime.
14 CFR 1214.1103 - Application cutoff date.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 5 2011-01-01 2010-01-01 true Application cutoff date. 1214.1103 Section 1214.1103 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION SPACE FLIGHT NASA Astronaut Candidate Recruitment and Selection Program § 1214.1103 Application cutoff date. (a) The JSC...
14 CFR 1214.1103 - Application cutoff date.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Application cutoff date. 1214.1103 Section 1214.1103 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION SPACE FLIGHT NASA Astronaut Candidate Recruitment and Selection Program § 1214.1103 Application cutoff date. (a) The JSC...
Measurement of electron density using reactance cutoff probe

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

You, K. H.; Seo, B. H.; Kim, J. H.

2016-05-15

This paper proposes a new measurement method of electron density using the reactance spectrum of the plasma in the cutoff probe system instead of the transmission spectrum. The highly accurate reactance spectrum of the plasma-cutoff probe system, as expected from previous circuit simulations [Kim et al., Appl. Phys. Lett. 99, 131502 (2011)], was measured using the full two-port error correction and automatic port extension methods of the network analyzer. The electron density can be obtained from the analysis of the measured reactance spectrum, based on circuit modeling. According to the circuit simulation results, the reactance cutoff probe can measure themore » electron density more precisely than the previous cutoff probe at low densities or at higher pressure. The obtained results for the electron density are presented and discussed for a wide range of experimental conditions, and this method is compared with previous methods (a cutoff probe using the transmission spectrum and a single Langmuir probe).« less
Nuclear materials safeguards for the future

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

Tape, J.W.

Basic concepts of domestic and international safeguards are described, with an emphasis on safeguards systems for the fuel cycles of commercial power reactors. Future trends in institutional and technical measures for nuclear materials safeguards are outlined. The conclusion is that continued developments in safeguards approaches and technology, coupled with institutional measures that facilitate the global management and protection of nuclear materials, are up to the challenge of safeguarding the growing inventories of nuclear materials in commercial fuel cycles in technologically advanced States with stable governments that have signed the nonproliferation treaty. These same approaches also show promise for facilitating internationalmore » inspection of excess weapons materials and verifying a fissile materials cutoff convention.« less
Physical and genetic-interaction density reveals functional organization and informs significance cutoffs in genome-wide screens

PubMed Central

Dittmar, John C.; Pierce, Steven; Rothstein, Rodney; Reid, Robert J. D.

2013-01-01

Genome-wide experiments often measure quantitative differences between treated and untreated cells to identify affected strains. For these studies, statistical models are typically used to determine significance cutoffs. We developed a method termed “CLIK” (Cutoff Linked to Interaction Knowledge) that overlays biological knowledge from the interactome on screen results to derive a cutoff. The method takes advantage of the fact that groups of functionally related interacting genes often respond similarly to experimental conditions and, thus, cluster in a ranked list of screen results. We applied CLIK analysis to five screens of the yeast gene disruption library and found that it defined a significance cutoff that differed from traditional statistics. Importantly, verification experiments revealed that the CLIK cutoff correlated with the position in the rank order where the rate of true positives drops off significantly. In addition, the gene sets defined by CLIK analysis often provide further biological perspectives. For example, applying CLIK analysis retrospectively to a screen for cisplatin sensitivity allowed us to identify the importance of the Hrq1 helicase in DNA crosslink repair. Furthermore, we demonstrate the utility of CLIK to determine optimal treatment conditions by analyzing genome-wide screens at multiple rapamycin concentrations. We show that CLIK is an extremely useful tool for evaluating screen quality, determining screen cutoffs, and comparing results between screens. Furthermore, because CLIK uses previously annotated interaction data to determine biologically informed cutoffs, it provides additional insights into screen results, which supplement traditional statistical approaches. PMID:23589890
Performance Evaluation of Different d-Dimer Cutoffs in Bedridden Hospitalized Elderly Patients.

PubMed

Kassim, Nevine A; Farid, Tamer M; Pessar, Shaimaa Abdelmalik; Shawkat, Salma A

2017-11-01

A rapid and accurate diagnosis of venous thromboembolism (VTE) in the elderly individuals represents a dilemma due to nonspecific clinical presentation, confusing laboratory results, and the hazards of radiological examination in this age-group. d-Dimer test is used mainly in combination with non-high clinical pretest probability (PTP) to exclude VTE. d-Dimer testing retains its sensitivity, however, its specificity decreases in the elderly individuals. Raising the cutoff level improves the specificity of the d-dimer test without compromising its sensitivity. The current study aimed to explore the reliability of higher d-dimer cutoff values for the diagnosis of asymptomatic VTE in a population of bedridden hospitalized elderly patients with non-high clinical PTP. This retrospective study included 252 bedridden hospitalized elderly patients (>65 years) who were admitted to the Ain shams University Specialized Hospital with non-high clinical probability and developed later reduced mobility; all underwent quantitation of d-dimer and Doppler examination. Considering the whole population (>65 years), the age-adjusted cutoff achieved the best performance in comparison with the conventional and receiver operating characteristic (ROC)-derived cutoffs. When stratified according to age, the age-adjusted cutoff showed the best performance in the age-group 65-70 and comparable performance with the ROC-derived cutoff in the age-group 71-80, however, its sensitivity compromised in those older than 80 years. In conclusion, it is recommended to use age-adjusted cutoff value of d-dimer together with the clinical probability score in elderly individuals (65-80 years).
Cutoff size need not strongly influence molecular dynamics results for solvated polypeptides.

PubMed

Beck, David A C; Armen, Roger S; Daggett, Valerie

2005-01-18

The correct treatment of van der Waals and electrostatic nonbonded interactions in molecular force fields is essential for performing realistic molecular dynamics (MD) simulations of solvated polypeptides. The most computationally tractable treatment of nonbonded interactions in MD utilizes a spherical distance cutoff (typically, 8-12 A) to reduce the number of pairwise interactions. In this work, we assess three spherical atom-based cutoff approaches for use with all-atom explicit solvent MD: abrupt truncation, a CHARMM-style electrostatic shift truncation, and our own force-shifted truncation. The chosen system for this study is an end-capped 17-residue alanine-based alpha-helical peptide, selected because of its use in previous computational and experimental studies. We compare the time-averaged helical content calculated from these MD trajectories with experiment. We also examine the effect of varying the cutoff treatment and distance on energy conservation. We find that the abrupt truncation approach is pathological in its inability to conserve energy. The CHARMM-style shift truncation performs quite well but suffers from energetic instability. On the other hand, the force-shifted spherical cutoff method conserves energy, correctly predicts the experimental helical content, and shows convergence in simulation statistics as the cutoff is increased. This work demonstrates that by using proper and rigorous techniques, it is possible to correctly model polypeptide dynamics in solution with a spherical cutoff. The inherent computational advantage of spherical cutoffs over Ewald summation (and related) techniques is essential in accessing longer MD time scales.
Impact of age cutoffs on a lynch syndrome screening program.

PubMed

Gudgeon, James M; Belnap, Thomas W; Williams, Janet L; Williams, Marc S

2013-07-01

To determine the impact of applying an age cutoff to tumor-based Lynch syndrome (LS) screening, specifically focusing on changes in relative effectiveness, efficiency, and cost. The project was undertaken to answer questions about implementation of the LS screening program in an integrated health care delivery system. Clinical data extracted from an internal cancer registry, previous modeling efforts, published literature, and gray data were used to populate decision models designed to answer questions about the impact of age cutoffs in LS screening. Patients with colorectal cancer (CRC) were stratified at 10-year intervals from ages 50 to 80 years and compared with no age cutoff. Outcomes are reported for a cohort of 325 patients screened and includes total cost to screen, LS cases present in the cutoff category, number of LS cases expected to be identified by screening, cost per LS case detected, and total number and percentage of LS cases missed. Applying an age cutoff to an LS screening program has considerable potential for decreasing total screening costs and increasing efficiency, but at a loss of effectiveness. Imposing an age cutoff of 50 years reduces the cost of the screening program to 16% of a program with no age cutoff, but at the expense of missing more than half of the cases. Failure to identify LS cases is magnified by a cascade effect in family members. The results of this analysis influenced the final policy in our system.
Evaluation of APRI and FIB-4 for noninvasive assessment of significant fibrosis and cirrhosis in HBeAg-negative CHB patients with ALT ≤ 2 ULN

PubMed Central

Li, Qiang; Ren, Xiaojing; Lu, Chuan; Li, Weixia; Huang, Yuxian; Chen, Liang

2017-01-01

Abstract To evaluate the performance of aspartate transaminase-to-platelet ratio index (APRI) and fibrosis index based on four factors (FIB-4) to predict significant fibrosis and cirrhosis in hepatitis B virus e antigen (HBeAg)-negative chronic hepatitis B (CHB) patients with alanine transaminase (ALT) ≤ twice the upper limit of normal (2 ULN). Histologic and laboratory data of 236 HBeAg-negative CHB patients with ALT ≤ 2 ULN were analyzed. Predicted fibrosis stage, based on established scales and cut-offs for APRI and FIB-4, was compared with METAVIR scores obtained from liver biopsy. In this study, the areas under the receiver operating characteristic curves (AUROCs) of APRI were lower than that of FIB-4 (0.62 vs 0.69; P = 0.019) for diagnosing significant fibrosis; however APRI and FIB-4 were comparable for diagnosing cirrhosis (0.77 vs 0.81; P = 0.374). When the cut-off proposed by WHO HBV guideline for APRI (>2.0) was used, no cirrhotic patients were correctly predicted. For FIB-4, the WHO proposed cut-off of 3.25 correctly identified significant fibrosis 83% of the time; but for APRI, the WHO proposed cut-off of 1.5 identified significant fibrosis 56%. In ruling out significant fibrosis, the WHO proposed APRI cut-off of 0.5 had a predictive value of 39%, and the FIB-4 cut-off of 1.45 correctly identified lack of significant fibrosis in 47% of the patients. In this study, based on ROC analysis, the optimal cut-offs were 0.46 and 0.65 for APRI, and 1.05 and 1.29 for FIB-4, for diagnosing significant fibrosis and cirrhosis, respectively. When the new cut-off of APRI (>0.65) was used, 82% of the cirrhotic patients were correctly predicted. In ruling out significant fibrosis, the new APRI cut-off (<0.46) had a predictive value of 80%, and new FIB-4 cut-off (<1.05) correctly identified lack of significant fibrosis in 84% of the patients. The WHO guidelines proposed cut-offs might be higher for HBeAg-negative CHB patients with ALT ≤2 ULN, and might underestimate the proportion of significant fibrosis and cirrhosis. A new set of cut-offs should be used to predict significant fibrosis and cirrhosis in this specific population. PMID:28328813
Evaluation of APRI and FIB-4 for noninvasive assessment of significant fibrosis and cirrhosis in HBeAg-negative CHB patients with ALT ≤ 2 ULN: A retrospective cohort study.

PubMed

Li, Qiang; Ren, Xiaojing; Lu, Chuan; Li, Weixia; Huang, Yuxian; Chen, Liang

2017-03-01

To evaluate the performance of aspartate transaminase-to-platelet ratio index (APRI) and fibrosis index based on four factors (FIB-4) to predict significant fibrosis and cirrhosis in hepatitis B virus e antigen (HBeAg)-negative chronic hepatitis B (CHB) patients with alanine transaminase (ALT) ≤ twice the upper limit of normal (2 ULN).Histologic and laboratory data of 236 HBeAg-negative CHB patients with ALT ≤ 2 ULN were analyzed. Predicted fibrosis stage, based on established scales and cut-offs for APRI and FIB-4, was compared with METAVIR scores obtained from liver biopsy.In this study, the areas under the receiver operating characteristic curves (AUROCs) of APRI were lower than that of FIB-4 (0.62 vs 0.69; P = 0.019) for diagnosing significant fibrosis; however APRI and FIB-4 were comparable for diagnosing cirrhosis (0.77 vs 0.81; P = 0.374). When the cut-off proposed by WHO HBV guideline for APRI (>2.0) was used, no cirrhotic patients were correctly predicted. For FIB-4, the WHO proposed cut-off of 3.25 correctly identified significant fibrosis 83% of the time; but for APRI, the WHO proposed cut-off of 1.5 identified significant fibrosis 56%. In ruling out significant fibrosis, the WHO proposed APRI cut-off of 0.5 had a predictive value of 39%, and the FIB-4 cut-off of 1.45 correctly identified lack of significant fibrosis in 47% of the patients. In this study, based on ROC analysis, the optimal cut-offs were 0.46 and 0.65 for APRI, and 1.05 and 1.29 for FIB-4, for diagnosing significant fibrosis and cirrhosis, respectively. When the new cut-off of APRI (>0.65) was used, 82% of the cirrhotic patients were correctly predicted. In ruling out significant fibrosis, the new APRI cut-off (<0.46) had a predictive value of 80%, and new FIB-4 cut-off (<1.05) correctly identified lack of significant fibrosis in 84% of the patients.The WHO guidelines proposed cut-offs might be higher for HBeAg-negative CHB patients with ALT ≤2 ULN, and might underestimate the proportion of significant fibrosis and cirrhosis. A new set of cut-offs should be used to predict significant fibrosis and cirrhosis in this specific population.

Stern-Gerlach-like approach to electron orbital angular momentum measurement

DOE PAGES

Harvey, Tyler R.; Grillo, Vincenzo; McMorran, Benjamin J.

2017-02-28

Many methods now exist to prepare free electrons into orbital-angular-momentum states, and the predicted applications of these electron states as probes of materials and scattering processes are numerous. The development of electron orbital-angular-momentum measurement techniques has lagged behind. We show that coupling between electron orbital angular momentum and a spatially varying magnetic field produces an angular-momentum-dependent focusing effect. We propose a design for an orbital-angular-momentum measurement device built on this principle. As the method of measurement is noninterferometric, the device works equally well for mixed, superposed, and pure final orbital-angular-momentum states. The energy and orbital-angular-momentum distributions of inelastically scattered electronsmore » may be simultaneously measurable with this technique.« less
Stern-Gerlach-like approach to electron orbital angular momentum measurement

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

Harvey, Tyler R.; Grillo, Vincenzo; McMorran, Benjamin J.

Many methods now exist to prepare free electrons into orbital-angular-momentum states, and the predicted applications of these electron states as probes of materials and scattering processes are numerous. The development of electron orbital-angular-momentum measurement techniques has lagged behind. We show that coupling between electron orbital angular momentum and a spatially varying magnetic field produces an angular-momentum-dependent focusing effect. We propose a design for an orbital-angular-momentum measurement device built on this principle. As the method of measurement is noninterferometric, the device works equally well for mixed, superposed, and pure final orbital-angular-momentum states. The energy and orbital-angular-momentum distributions of inelastically scattered electronsmore » may be simultaneously measurable with this technique.« less
Linear and angular control of circular walking in healthy older adults and subjects with cerebellar ataxia.

PubMed

Goodworth, Adam D; Paquette, Caroline; Jones, Geoffrey Melvill; Block, Edward W; Fletcher, William A; Hu, Bin; Horak, Fay B

2012-05-01

Linear and angular control of trunk and leg motion during curvilinear navigation was investigated in subjects with cerebellar ataxia and age-matched control subjects. Subjects walked with eyes open around a 1.2-m circle. The relationship of linear to angular motion was quantified by determining the ratios of trunk linear velocity to trunk angular velocity and foot linear position to foot angular position. Errors in walking radius (the ratio of linear to angular motion) also were quantified continuously during the circular walk. Relative variability of linear and angular measures was compared using coefficients of variation (CoV). Patterns of variability were compared using power spectral analysis for the trunk and auto-covariance analysis for the feet. Errors in radius were significantly increased in patients with cerebellar damage as compared to controls. Cerebellar subjects had significantly larger CoV of feet and trunk in angular, but not linear, motion. Control subjects also showed larger CoV in angular compared to linear motion of the feet and trunk. Angular and linear components of stepping differed in that angular, but not linear, foot placement had a negative correlation from one stride to the next. Thus, walking in a circle was associated with more, and a different type of, variability in angular compared to linear motion. Results are consistent with increased difficulty of, and role of the cerebellum in, control of angular trunk and foot motion for curvilinear locomotion.
INVESTIGATION OF CONVENTIONAL MEMBRANE AND TANGENTIAL FLOW ULTRAFILTRATION ARTIFACTS AND THEIR APPLICATION TO THE CHARACTERIZATION OF FRESHWATER COLLOIDS

EPA Science Inventory

Artifacts associated with the fractionation of colloids in a freshwater sample were investigated for conventional membrane filtration (0.45 micron cutoff), and two tangential flow ultrafiltration cartridges (0.1 micron cutoff and 3000 MW cutoff). Membrane clogging during conventi...
On Computations of Duct Acoustics with Near Cut-Off Frequency

NASA Technical Reports Server (NTRS)

Dong, Thomas Z.; Povinelli, Louis A.

1997-01-01

The cut-off is a unique feature associated with duct acoustics due to the presence of duct walls. A study of this cut-off effect on the computations of duct acoustics is performed in the present work. The results show that the computation of duct acoustic modes near cut-off requires higher numerical resolutions than others to avoid being numerically cut off. Duct acoustic problems in Category 2 are solved by the DRP finite difference scheme with the selective artificial damping method and results are presented and compared to reference solutions.
Information theory, spectral geometry, and quantum gravity.

PubMed

Kempf, Achim; Martin, Robert

2008-01-18

We show that there exists a deep link between the two disciplines of information theory and spectral geometry. This allows us to obtain new results on a well-known quantum gravity motivated natural ultraviolet cutoff which describes an upper bound on the spatial density of information. Concretely, we show that, together with an infrared cutoff, this natural ultraviolet cutoff beautifully reduces the path integral of quantum field theory on curved space to a finite number of ordinary integrations. We then show, in particular, that the subsequent removal of the infrared cutoff is safe.
A Method of Implementing Cutoff Conditions for Saturn V Lunar Missions Out of Earth Parking Orbit Assuming a Continuous Ground Launch Window

NASA Technical Reports Server (NTRS)

Cooper, F. D.

1965-01-01

A method of implementing Saturn V lunar missions from an earth parking orbit is presented. The ground launch window is assumed continuous over a four and one-half hour period. The iterative guidance scheme combined with a set of auxiliary equations that define suitable S-IVB cutoff conditions, is the approach taken. The four inputs to the equations that define cutoff conditions are represented as simple third-degree polynomials as a function of ignition time. Errors at lunar arrival caused by the separate and combined effects of the guidance equations, cutoff conditions, hypersurface errors, and input representations are shown. Vehicle performance variations and parking orbit injection errors are included as perturbations. Appendix I explains how aim vectors were computed for the cutoff equations. Appendix II presents all guidance equations and related implementation procedures. Appendix III gives the derivation of the auxiliary cutoff equations. No error at lunar arrival was large enough to require a midcourse correction greater than one meter per second assuming a transfer time of three days and the midcourse correction occurs five hours after injection. Since this result is insignificant when compared to expected hardware errors, the implementation procedures presented are adequate to define cutoff conditions for Saturn V lunar missions.
The theoretical and practical determination of clinical cut-offs for the British Sign Language versions of PHQ-9 and GAD-7.

PubMed

Belk, Rachel A; Pilling, Mark; Rogers, Katherine D; Lovell, Karina; Young, Alys

2016-11-03

The PHQ-9 and the GAD-7 assess depression and anxiety respectively. There are standardised, reliability-tested versions in BSL (British Sign Language) that are used with Deaf users of the IAPT service. The aim of this study is to determine their appropriate clinical cut-offs when used with Deaf people who sign and to examine the operating characteristics for PHQ-9 BSL and GAD-7 BSL with a clinical Deaf population. Two datasets were compared: (i) dataset (n = 502) from a specialist IAPT service for Deaf people; and (ii) dataset (n = 85) from our existing study of Deaf people who self-reported having no mental health difficulties. Parameter estimates, with the precision of AUC value, sensitivity, specificity, positive predicted value (ppv) and negative predicted value (npv), were carried out to provide the details of the clinical cut-offs. Three statistical choices were included: Maximising (Youden: maximising sensitivity + specificity), Equalising (Sensitivity = Specificity) and Prioritising treatment (False Negative twice as bad as False Positive). Standard measures (as defined by IAPT) were applied to examine caseness, recovery, reliable change and reliable recovery for the first dataset. The clinical cut-offs for PHQ-9 BSL and GAD-7 BSL are 8 and 6 respectively. This compares with the original English version cut-offs in the hearing population of 10 and 8 respectively. The three different statistical choices for calculating clinical cut-offs all showed a lower clinical cut-off for the Deaf population with respect to the PHQ-9 BSL and GAD-7 BSL with the exception of the Maximising criteria when used with the PHQ-9 BSL. Applying the new clinical cut-offs, the percentage of Deaf BSL IAPT service users showing reliable recovery is 54.0 % compared to 63.7 % using the cut-off scores used for English speaking hearing people. These compare favourably with national IAPT data for the general population. The correct clinical cut-offs for the PHQ-9 BSL and GAD-7 BSL enable meaningful measures of clinical effectiveness and facilitate appropriate access to treatment when required.
Is there a pattern to oxbow lake geomorphic evolution?

NASA Astrophysics Data System (ADS)

Dieras, P.; Constantine, J. A.

2012-04-01

Oxbow lakes are located along the floodplain corridor and created after meander cutoff. They are of high ecological value as they provide relatively calm wetlands which are regularly supplied with nutrients during floods. The persistence of oxbow lakes has been observed to vary from decades to several hundreds of years but little is known about the controls on their longevity. This study aims to ascertain if there is a common pattern in the water decrease of oxbow lakes and to define the controls on the lakes' longevity. The longevity of 37 oxbow lakes from 7 rivers from different parts of the world has been studied. The Towy River (Wales), the Ain River (France) and the Sacramento River (CA, USA) are largely dominated by oxbow lakes created after chute cutoff which is the incision of a chute across the floodplain; whereas the Mississippi River (MS, USA), the Kansas River (KS, USA), the Red River (MN, USA) and the Otter Tail River (MN, USA) show a large number of neck cutoffs which occur when two meanders migrate into one another. The water surface area decrease has been measured for all the sites using aerial photographs. Results revealed that the longevity of oxbow lakes is significantly affected by the type of cutoff. The lakes formed by chute cutoff lose very rapidly most of the water surface area of the initial channel as it is reduce by >80% within the first 10 to 30 years following cutoff for most sites. The water surface area of chute cutoff shows a logarithmic decrease with a fast decrease rate following cutoff, followed by a much slower loss of water surface area. The change in water decrease rate appears to be related to the moment of obstruction of the former channel entrance by sediment aggradation. In contrast, lakes formed by neck cutoff persist for much longer in the landscape and lose 40 to 60% within the first decades but then they maintain this water surface area for longer than a century. The cutoff process is therefore the main control on the persistence of oxbow lakes and has important impact on the habitats on the floodplain corridor.
Tractography of Association Fibers Associated with Language Processing.

PubMed

Egger, K; Yang, S; Reisert, M; Kaller, C; Mader, I; Beume, L; Weiller, C; Urbach, H

2015-10-01

Several major association fiber tracts are known to be part of the language processing system. There is evidence that high angular diffusion-based MRI is able to separate these fascicles in a constant way. In this study, we wanted to proof this thesis using a novel whole brain "global tracking" approach and to test for possible lateralization. Global tracking was performed in six healthy right-handed volunteers for the arcuate fascicle (AF), the medial longitudinal fascicle (MdLF), the inferior fronto-occipital fascicle (IFOF), and the inferior longitudinal fascicle (ILF). These fiber tracts were characterized quantitatively using the number of streamlines (SL) and the mean fractional anisotropy (FA). We were able to characterize the AF, the MdLF, the IFOF, and the ILF consistently in six healthy volunteers using global tracking. A left-sided dominance (LI > 0.2) for the AF was found in all participants. The MdLF showed a left-sided dominance in four participants (one female, three male). Regarding the FA, no lateralization (LI > 0.2) could be shown in any of the fascicles. Using a novel global tracking algorithm we confirmed that the courses of the primary language processing associated fascicles can consistently be differentiated. Additionally we were able to show a streamline-based left-sided lateralization in the AF of all right-handed healthy subjects.
Digital Filtering of Three-Dimensional Lower Extremity Kinematics: an Assessment

PubMed Central

Sinclair, Jonathan; Taylor, Paul John; Hobbs, Sarah Jane

2013-01-01

Errors in kinematic data are referred to as noise and are an undesirable portion of any waveform. Noise is typically removed using a low-pass filter which removes the high frequency components of the signal. The selection of an optimal frequency cut-off is very important when processing kinematic information and a number of techniques exists for the determination of an optimal frequency cut-off. Despite the importance of cut-off frequency to the efficacy of kinematic analyses there is currently a paucity of research examining the influence of different cut-off frequencies on the resultant 3-D kinematic waveforms and discrete parameters. Twenty participants ran at 4.0 m•s−1 as lower extremity kinematics in the sagittal, coronal and transverse planes were measured using an eight camera motion analysis system. The data were filtered at a range of cut-off frequencies and the discrete kinematic parameters were examined using repeated measures ANOVA’s. The similarity between the raw and filtered waveforms were examined using intra-class correlations. The results show that the cut-off frequency has a significant influence on the discrete kinematic measure across displacement and derivative information in all three planes of rotation. Furthermore, it was also revealed that as the cut-off frequency decreased the attenuation of the kinematic waveforms became more pronounced, particularly in the coronal and transverse planes at the second derivative. In conclusion, this investigation provides new information regarding the influence of digital filtering on lower extremity kinematics and re-emphasizes the importance of selecting the correct cut-off frequency. PMID:24511338
Cost-effectiveness analysis of a quantitative immunochemical test for colorectal cancer screening.

PubMed

Wilschut, Janneke A; Hol, Lieke; Dekker, Evelien; Jansen, Jan B; Van Leerdam, Monique E; Lansdorp-Vogelaar, Iris; Kuipers, Ernst J; Habbema, J Dik F; Van Ballegooijen, Marjolein

2011-11-01

Two European randomized trials (N = 30,000) compared guaiac fecal occult blood testing with quantitative fecal immunochemical testing (FIT) and showed better attendance rates and test characteristics for FIT. We aimed to identify the most cost-effective FIT cutoff level for referral to colonoscopy based on data from these trials and allowing for differences in screening ages. We used the validated MIcrosimulation SCreening ANalysis (MISCAN)-Colon microsimulation model to estimate costs and effects of different screening strategies for FIT cutoff levels of 50, 75, 100, 150, and 200 ng/mL hemoglobin. For each cutoff level, screening strategies were assessed with various age ranges and screening intervals. We assumed sufficient colonoscopy capacity for all strategies. At all cost levels, FIT screening was most effective with the 50 ng/mL cutoff level. The incremental cost-effectiveness ratio of biennial screening between ages 55 and 75 years using FIT at 50 ng/mL, for example, was 3900 euro per life year gained. Annual screening had an incremental cost-effectiveness ratio of 14,900 euro per life year gained, in combination with a wider age range (between ages 45 and 80 years). In the sensitivity analysis, 50 ng/mL remained the preferred cutoff level. FIT screening is more cost-effective at a cutoff level of 50 ng/mL than at higher cutoff levels. This supports the recommendation to use FIT at a cutoff level of 50 ng/mL, which is considerably lower than the values used in current practice. Copyright © 2011 AGA Institute. Published by Elsevier Inc. All rights reserved.
Assessment of second (I2M) and third (I3M) molar indices for establishing 14 and 16 legal ages and validation of the Cameriere's I3M cut-off for 18 years old in Chilean population.

PubMed

Cameriere, Roberto; Velandia Palacio, Luz Andrea; Pinares, Jorge; Bestetti, Fiorella; Paba, Rossella; Coccia, Erminia; Ferrante, Luigi

2018-04-01

This retrospective cross-sectional study has two-fold aims: the first is to assess new cut-offs at the legal age thresholds (LATs) of 14 and 16 years old and the second is to validate the cut-off of third molar index I 3M =0.08 for 18 years of age in Chilean people. Orthopantomographs from 822 Chilean children aged from 11 to 22 (472 girls and 350 boys) were analysed. For LAT of 14 years, cut-offs were found using the ROC curves singly for boys and girls. The cut-offs for boys were I 2M =0.16 and I 3M =0.73 while for girls we obtained I 2M =0.10 and I 3M =0.77. For LAT of 16 years we obtained the same cut-offs regardless of gender, which were 0.06 and 0.36 for I 2M and I 3M respectively. Concerning the validity of I 3M cut-off for 18 years old in Chilean population, the proportion of correctly classified individuals was 83% and estimated post-test probability, PPV, was 93.2%, with a 95% confidence interval equals to 91.3%, 94.6%. Hence, the probability that a subject positive on the test was 18 years of age or older was 93.2%, confirming the validation of the I 3M cut-off for Chilean population. Copyright © 2018 Elsevier B.V. All rights reserved.
Depression screening via a smartphone app: cross-country user characteristics and feasibility.

PubMed

BinDhim, Nasser F; Shaman, Ahmed M; Trevena, Lyndal; Basyouni, Mada H; Pont, Lisa G; Alhawassi, Tariq M

2015-01-01

Smartphone applications (apps) have the potential to be valuable self-help interventions for depression screening. However, information about their feasibility and effectiveness and the characteristics of app users is limited. The aim of this study is to explore the uptake, utilization, and characteristics of voluntary users of an app for depression screening. This was a cross-sectional study of a free depression screening smartphone app that contains the demographics, patient health questionnaire (PHQ-9), brief anxiety test, personalized recommendation based on the participant's results, and links to depression-relevant websites. The free app was released globally via Apple's App Store. Participants aged 18 and older downloaded the study app and were recruited passively between September 2012 and January 2013. 8241 participants from 66 countries had downloaded the app, with a response rate of 73.9%. While one quarter of the participants had a previous diagnosis of depression, the prevalence of participants with a higher risk of depression was 82.5% and 66.8% at PHQ-9 cut-off 11 and cut-off 15, respectively. Many of the participants had one or more physical comorbid conditions and suicidal ideation. The cut-off 11 (OR: 1.4; 95% CI 1.2 to 1.6), previous depression diagnosis (OR: 1.3; 95% CI1.2 to 1.5), and postgraduate educational level (OR: 1.2; 95% CI 1.0 to 1.5) were associated with completing the PHQ-9 questionnaire more than once. Smartphone apps can be used to deliver a screening tool for depression across a large number of countries. Apps have the potential to play a significant role in disease screening, self-management, monitoring, and health education, particularly among younger adults. © The Author 2014. Published by Oxford University Press on behalf of the American Medical Informatics Association. All rights reserved. For Permissions, please email: journals.permissions@oup.comFor numbered affiliations see end of article.
Comparison of World Health Organization and Asia-Pacific body mass index classifications in COPD patients.

PubMed

Lim, Jeong Uk; Lee, Jae Ha; Kim, Ju Sang; Hwang, Yong Il; Kim, Tae-Hyung; Lim, Seong Yong; Yoo, Kwang Ha; Jung, Ki-Suck; Kim, Young Kyoon; Rhee, Chin Kook

2017-01-01

A low body mass index (BMI) is associated with increased mortality and low health-related quality of life in patients with COPD. The Asia-Pacific classification of BMI has a lower cutoff for overweight and obese categories compared to the World Health Organization (WHO) classification. The present study assessed patients with COPD among different BMI categories according to two BMI classification systems: WHO and Asia-Pacific. Patients with COPD aged 40 years or older from the Korean COPD Subtype Study cohort were selected for evaluation. We enrolled 1,462 patients. Medical history including age, sex, St George's Respiratory Questionnaire (SGRQ-C), the modified Medical Research Council (mMRC) dyspnea scale, and post-bronchodilator forced expiratory volume in 1 second (FEV 1 ) were evaluated. Patients were categorized into different BMI groups according to the two BMI classification systems. FEV 1 and the diffusing capacity of the lung for carbon monoxide (DLCO) percentage revealed an inverse "U"-shaped pattern as the BMI groups changed from underweight to obese when WHO cutoffs were applied. When Asia-Pacific cutoffs were applied, FEV 1 and DLCO (%) exhibited a linearly ascending relationship as the BMI increased, and the percentage of patients in the overweight and obese groups linearly decreased with increasing severity of the Global Initiative for Chronic Obstructive Lung Disease criteria. From the underweight to the overweight groups, SGRQ-C and mMRC had a decreasing relationship in both the WHO and Asia-Pacific classifications. The prevalence of comorbidities in the different BMI groups showed similar trends in both BMI classifications systems. The present study demonstrated that patients with COPD who have a high BMI have better pulmonary function and health-related quality of life and reduced dyspnea symptoms. Furthermore, the Asia-Pacific BMI classification more appropriately reflects the correlation of obesity and disease manifestation in Asian COPD patients than the WHO classification.
Mapping tissue inhomogeneity in acute myocarditis: a novel analytical approach to quantitative myocardial edema imaging by T2-mapping.

PubMed

Baeßler, Bettina; Schaarschmidt, Frank; Dick, Anastasia; Stehning, Christian; Schnackenburg, Bernhard; Michels, Guido; Maintz, David; Bunck, Alexander C

2015-12-23

The purpose of the present study was to investigate the diagnostic value of T2-mapping in acute myocarditis (ACM) and to define cut-off values for edema detection. Cardiovascular magnetic resonance (CMR) data of 31 patients with ACM were retrospectively analyzed. 30 healthy volunteers (HV) served as a control. Additionally to the routine CMR protocol, T2-mapping data were acquired at 1.5 T using a breathhold Gradient-Spin-Echo T2-mapping sequence in six short axis slices. T2-maps were segmented according to the 16-segments AHA-model and segmental T2 values as well as the segmental pixel-standard deviation (SD) were analyzed. Mean differences of global myocardial T2 or pixel-SD between HV and ACM patients were only small, lying in the normal range of HV. In contrast, variation of segmental T2 values and pixel-SD was much larger in ACM patients compared to HV. In random forests and multiple logistic regression analyses, the combination of the highest segmental T2 value within each patient (maxT2) and the mean absolute deviation (MAD) of log-transformed pixel-SD (madSD) over all 16 segments within each patient proved to be the best discriminators between HV and ACM patients with an AUC of 0.85 in ROC-analysis. In classification trees, a combined cut-off of 0.22 for madSD and of 68 ms for maxT2 resulted in 83% specificity and 81% sensitivity for detection of ACM. The proposed cut-off values for maxT2 and madSD in the setting of ACM allow edema detection with high sensitivity and specificity and therefore have the potential to overcome the hurdles of T2-mapping for its integration into clinical routine.
Capacity of non-invasive hepatic fibrosis algorithms to replace transient elastography to exclude cirrhosis in people with hepatitis C virus infection: A multi-centre observational study

PubMed Central

Riordan, Stephen M.; Bopage, Rohan; Lloyd, Andrew R.

2018-01-01

Introduction Achievement of the 2030 World Health Organisation (WHO) global hepatitis C virus (HCV) elimination targets will be underpinned by scale-up of testing and use of direct-acting antiviral treatments. In Australia, despite publically-funded testing and treatment, less than 15% of patients were treated in the first year of treatment access, highlighting the need for greater efficiency of health service delivery. To this end, non-invasive fibrosis algorithms were examined to reduce reliance on transient elastography (TE) which is currently utilised for the assessment of cirrhosis in most Australian clinical settings. Materials and methods This retrospective and prospective study, with derivation and validation cohorts, examined consecutive patients in a tertiary referral centre, a sexual health clinic, and a prison-based hepatitis program. The negative predictive value (NPV) of seven non-invasive algorithms were measured using published and newly derived cut-offs. The number of TEs avoided for each algorithm, or combination of algorithms, was determined. Results The 850 patients included 780 (92%) with HCV mono-infection, and 70 (8%) co-infected with HIV or hepatitis B. The mono-infected cohort included 612 men (79%), with an overall prevalence of cirrhosis of 16% (125/780). An ‘APRI’ algorithm cut-off of 1.0 had a 94% NPV (95%CI: 91–96%). Newly derived cut-offs of ‘APRI’ (0.49), ‘FIB-4’ (0.93) and ‘GUCI’ (0.5) algorithms each had NPVs of 99% (95%CI: 97–100%), allowing avoidance of TE in 40% (315/780), 40% (310/780) and 40% (298/749) respectively. When used in combination, NPV was retained and TE avoidance reached 54% (405/749), regardless of gender or co-infection. Conclusions Non-invasive algorithms can reliably exclude cirrhosis in many patients, allowing improved efficiency of HCV assessment services in Australia and worldwide. PMID:29438397
Capacity of non-invasive hepatic fibrosis algorithms to replace transient elastography to exclude cirrhosis in people with hepatitis C virus infection: A multi-centre observational study.

PubMed

Kelly, Melissa Louise; Riordan, Stephen M; Bopage, Rohan; Lloyd, Andrew R; Post, Jeffrey John

2018-01-01

Achievement of the 2030 World Health Organisation (WHO) global hepatitis C virus (HCV) elimination targets will be underpinned by scale-up of testing and use of direct-acting antiviral treatments. In Australia, despite publically-funded testing and treatment, less than 15% of patients were treated in the first year of treatment access, highlighting the need for greater efficiency of health service delivery. To this end, non-invasive fibrosis algorithms were examined to reduce reliance on transient elastography (TE) which is currently utilised for the assessment of cirrhosis in most Australian clinical settings. This retrospective and prospective study, with derivation and validation cohorts, examined consecutive patients in a tertiary referral centre, a sexual health clinic, and a prison-based hepatitis program. The negative predictive value (NPV) of seven non-invasive algorithms were measured using published and newly derived cut-offs. The number of TEs avoided for each algorithm, or combination of algorithms, was determined. The 850 patients included 780 (92%) with HCV mono-infection, and 70 (8%) co-infected with HIV or hepatitis B. The mono-infected cohort included 612 men (79%), with an overall prevalence of cirrhosis of 16% (125/780). An 'APRI' algorithm cut-off of 1.0 had a 94% NPV (95%CI: 91-96%). Newly derived cut-offs of 'APRI' (0.49), 'FIB-4' (0.93) and 'GUCI' (0.5) algorithms each had NPVs of 99% (95%CI: 97-100%), allowing avoidance of TE in 40% (315/780), 40% (310/780) and 40% (298/749) respectively. When used in combination, NPV was retained and TE avoidance reached 54% (405/749), regardless of gender or co-infection. Non-invasive algorithms can reliably exclude cirrhosis in many patients, allowing improved efficiency of HCV assessment services in Australia and worldwide.
Palaeomagnetism of the Western and Central sectors of the Trans-Mexican volcanic belt-implications for tectonic rotations and palaeosecular variation in the past 11 Ma

NASA Astrophysics Data System (ADS)

Ruiz-Martínez, V. C.; Urrutia-Fucugauchi, J.; Osete, M. L.

2010-02-01

New palaeomagnetic data from the central and western sectors of the Trans-Mexican volcanic belt (TMVB) are presented and analysed for palaeosecular variation (PSV) and tectonic rotations. Fifty-one sites with geochronological control were collected from selected volcanic lava flows, which cover the temporal and spatial activity in the magmatic arc for the past ~11 Ma. Rock magnetic experiments reveal that generally Ti-poor titanomagnetites, sometimes maghemitized, are the magnetic carriers of the characteristic remanent magnetizations. After analysis of detailed progressive demagnetization data, 47 mean-site directions are determined. In addition, data from previous regional palaeomagnetic study in the eastern TMVB sector (53 sites) are re-analysed. Palaeomagnetic data are grouped according to geographic distribution (three structural sectors) and according to age (late Miocene, Pliocene or Quaternary). To avoid discarding tectonic effects, the less stringent criterion (i.e. a fixed cut-off angle to the mean equal to 45°) was applied to identify transitional data, affecting four sites. Palaeomagnetic results, backed by positive reversal tests, indicate no palaeomagnetically detectable vertical-axis block rotations in the study areas. The nearly geocentric axial dipole (GAD) inclinations suggest no significant tilting effects and negligible quadrupolar contributions. Since the mean palaeomagnetic directions for the study areas do not differ from reference directions from the North American polar wander path, two data sets for 11-5 and 5-0 Ma are tested for geomagnetic purposes. Virtual geomagnetic poles (VGPs) were selected using both fixed -45°- and optimum, variable cut-off angles. This resulted in VGP dispersions that increase back on time and are consistent with those obtained from globally distributed observations at the site latitude for their respective age ranges and cut-off criteria. Palaeomagnetic data from late Miocene and Pliocene TMVB rocks can be considered in the databases for time averaged field (TAF) and palaeosecular variation from lavas (PSVL) analyses and geomagnetic field geometry characterization during the past ~11 Ma.
Statistical Considerations for Establishing CBTE Cut-Off Scores.

ERIC Educational Resources Information Center

Trzasko, Joseph A.

This report gives the basic definition and purpose of competency-based teacher education (CBTE) cut-off scores. It describes the basic characteristics of CBTE as a yes-no dichotomous decision regarding the presence of a specific ability or knowledge, which necesitates the establishment of a cut-off point to designate competency vs. incompetency on…

33 CFR 117.465 - Lafourche Bayou.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., mile 23.9, at Golden Meadow (2) Galliano Pontoon Bridge, mile 27.8, at Galliano (3) SR 308 (South Lafourche (Tarpon)) Bridge, mile 30.6, at Galliano (4) Cote Blanche Pontoon Bridge, mile 33.9, at Cutoff (5) Cutoff Vertical Lift Bridge, mile 36.3, at Cutoff (6) SR 310 (Larose Pontoon) Bridge, mile 39.1, at...
75 FR 13636 - Self-Regulatory Organizations; International Securities Exchange, LLC; Order Approving Proposed...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-22

... Rules Related to Cut-Off Time for Contrary Exercise Advice Submissions March 15, 2010. I. Introduction... to the cut-off time for submitting contrary exercise advices to the Exchange. The proposed rule... proposed to amend Rule 1100 to extend the cut-off time to submit contrary exercise advices (``CEAs'') \\4...
10 CFR 26.131 - Cutoff levels for validity screening and initial validity tests.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Cutoff levels for validity screening and initial validity tests. 26.131 Section 26.131 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Licensee Testing Facilities § 26.131 Cutoff levels for validity screening and initial validity tests. (a) Each...
10 CFR 26.131 - Cutoff levels for validity screening and initial validity tests.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Cutoff levels for validity screening and initial validity tests. 26.131 Section 26.131 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Licensee Testing Facilities § 26.131 Cutoff levels for validity screening and initial validity tests. (a) Each...
Cutoff Criteria for Fit Indexes in Covariance Structure Analysis: Conventional Criteria versus New Alternatives.

ERIC Educational Resources Information Center

Hu, Li-tze; Bentler, Peter M.

1999-01-01

The adequacy of "rule of thumb" conventional cutoff criteria and several alternatives for fit indices in covariance structure analysis was evaluated through simulation. Analyses suggest that, for all recommended fit indexes except one, a cutoff criterion greater than (or sometimes smaller than) the conventional rule of thumb is required…
Retrieval of Understory NDVI in Sparse Boreal Forests By MODIS Brdf Data

NASA Astrophysics Data System (ADS)

Yang, W.; Kobayashi, H.; Suzuki, R.; Nasahara, K. N.

2014-12-01

Global products of leaf area index (LAI) usually show large uncertainties in sparsely vegetated areas. The reason is that the understory contribution is not negligible in reflectance modeling for the case of low to intermediate canopy cover. Therefore many efforts have been carried out on inclusion of understory properties in the LAI estimation algorithms. Compared with conventional data bank method, estimation of forest understory property from satellite data is superior in the studies at global or continental scale during a long periods. However, the existing remote sensing method based on multi-angular observations is very complicated to implement. Alternatively, a simple method to retrieve understory NDVI (NDVIu) for sparse boreal forests was proposed in this study. The method is based on the property that the bi-directional variation of NDVIu is much smaller than that of the canopy-level NDVI. To retrieve NDVIu for a certain pixel, linear extrapolation was applied using the pixels within a 5×5 target-pixel-centered window. The NDVI values were reconstructed from the MODIS BRDF data corresponding to eight different solar-view angles. NDVIu was estimated as the average of the NDVI values corresponding to the position where the stand NDVI has the smallest angular variation. Validation by noise-free simulation dataset yielded high agreement between estimated and true NDVIu with R2 and RMSE of 0.99 and 0.03, respectively. By the MODIS BRDF data, we got the estimate of NDVIu close to the in situ measured value (0.61 vs. 0.66 for estimate and measurement, respectively), and also reasonable seasonal patterns of NDVIu in 2010-2013. The results imply a potential application of the retrieved NDVIu to improve the estimation of overstory LAI for sparse boreal forests.
High Frequency Variations of Earth Rotation Parameters from GPS and GLONASS Observations

PubMed Central

Wei, Erhu; Jin, Shuanggen; Wan, Lihua; Liu, Wenjie; Yang, Yali; Hu, Zhenghong

2015-01-01

The Earth's rotation undergoes changes with the influence of geophysical factors, such as Earth's surface fluid mass redistribution of the atmosphere, ocean and hydrology. However, variations of Earth Rotation Parameters (ERP) are still not well understood, particularly the short-period variations (e.g., diurnal and semi-diurnal variations) and their causes. In this paper, the hourly time series of Earth Rotation Parameters are estimated using Global Positioning System (GPS), Global Navigation Satellite System (GLONASS), and combining GPS and GLONASS data collected from nearly 80 sites from 1 November 2012 to 10 April 2014. These new observations with combining different satellite systems can help to decorrelate orbit biases and ERP, which improve estimation of ERP. The high frequency variations of ERP are analyzed using a de-trending method. The maximum of total diurnal and semidiurnal variations are within one milli-arcseconds (mas) in Polar Motion (PM) and 0.5 milli-seconds (ms) in UT1-UTC. The semidiurnal and diurnal variations are mainly related to the ocean tides. Furthermore, the impacts of satellite orbit and time interval used to determinate ERP on the amplitudes of tidal terms are analyzed. We obtain some small terms that are not described in the ocean tide model of the IERS Conventions 2010, which may be caused by the strategies and models we used or the signal noises as well as artifacts. In addition, there are also small differences on the amplitudes between our results and IERS convention. This might be a result of other geophysical excitations, such as the high-frequency variations in atmospheric angular momentum (AAM) and hydrological angular momentum (HAM), which needs more detailed analysis with more geophysical data in the future. PMID:25635416
Open pit mining profit maximization considering selling stage and waste rehabilitation cost

NASA Astrophysics Data System (ADS)

Muttaqin, B. I. A.; Rosyidi, C. N.

2017-11-01

In open pit mining activities, determination of the cut-off grade becomes crucial for the company since the cut-off grade affects how much profit will be earned for the mining company. In this study, we developed a cut-off grade determination mode for the open pit mining industry considering the cost of mining, waste removal (rehabilitation) cost, processing cost, fixed cost, and selling stage cost. The main goal of this study is to develop a model of cut-off grade determination to get the maximum total profit. Secondly, this study is also developed to observe the model of sensitivity based on changes in the cost components. The optimization results show that the models can help mining company managers to determine the optimal cut-off grade and also estimate how much profit that can be earned by the mining company. To illustrate the application of the models, a numerical example and a set of sensitivity analysis are presented. From the results of sensitivity analysis, we conclude that the changes in the sales price greatly affects the optimal cut-off value and the total profit.
Cut-off characterisation of energy spectra of bright Fermi sources: Current instrument limits and future possibilities

NASA Astrophysics Data System (ADS)

Romoli, Carlo; Taylor, Andrew M.; Aharonian, Felix

2017-01-01

The cut-off region of the gamma-ray spectrum of astrophysical sources encodes important information about the acceleration processes producing the parent particle population. For bright AGNs the cut-off happens in an energy range around a few tens of GeV, a region where satellites are limited by their effective area and current ground based telescopes by energy threshold. In the attempt to maximise the statistics, we have looked at two of the brightest AGNs seen by the Fermi-LAT (3C 454.3 and 3C 279) during extremely luminous flares. Our analysis showed the difficulty to obtain good constraints on the cut-off parameters when a power-law with modified exponential cut-off was assumed to fit the SEDs. We discuss the potential of future low-threshold Cherenkov telescope arrays, in particular CTA, showing the impact that a much bigger effective area can have on the determination of spectral parameters in the cut-off region. This preliminary study serves as an example, demonstrating the importance of having good wide-energy coverage around 10 GeV.
Study of Proton cutoffs during geomagnetically disturbed times

NASA Astrophysics Data System (ADS)

Kanekal, S. G.; Looper, M. D.; Baker, D. N.; Blake, J. B.

2005-12-01

It is currently believed that solar energetic particles (SEP) may be accelerated at solar flares and/or at interplanetary shocks driven by coronal mass ejections (CMEs). CMEs also cause intense geomagnetic storms during which the geomagnetic field can be highly distorted.SEP fluxes penetrate the terrestrial magnetosphere and reach specific regions depending upon the geomagnetic field configuration. The cutoff latitude is a well defined latitude below which a charged particle of a given rigidity (momentum per unit charge) arriving from a given direction cannot penetrate. SEP cutoff location can therefore be potentially useful in determining the geomagnetic field configuration. This paper reports on the measurements of solar energetic proton cutoffs made by two satellites, SAMPEX and Polar during geomagnetically disturbed times. We study select SEP events and compare our measurements with cutoffs calculated by a charged particle tracing code which utilizes several currently used models of the geomagnetic field. The measured SEP proton cutoffs cover a wide range of rigidities and are obtained at high-altitudes by the HIST detector onboard Polar and at low-altitudes by the PET detctor onboard SAMPEX.
The impact of an underground cut-off wall on nutrient dynamics in groundwater in the lower Wang River watershed, China.

PubMed

Kang, Pingping; Xu, Shiguo

2017-03-01

Underground cut-off walls in coastal regions are mainly used to prevent saltwater intrusion, but their impact on nutrient dynamics in groundwater is not clear. In this study, a combined analysis of multiple isotopes ([Formula: see text]) and nitrogen and phosphorus concentrations is used in order to assess the impact of the underground cut-off walls on the nutrient dynamics in groundwater in the lower Wang River watershed, China. Compared with the nitrogen and phosphorus concentrations in groundwater downstream of the underground cut-off walls, high [Formula: see text] and total dissolved nitrogen concentrations and similar concentration levels of [Formula: see text] and total dissolved phosphorus are found in groundwater upstream of the underground cut-off walls. The isotopic data indicated the probable occurrence of denitrification and nitrification processes in groundwater upstream, whereas the fingerprint of these processes was not shown in groundwater downstream. The management of fertilizer application is critical to control nitrogen concentrations in groundwater restricted by the underground cut-off walls.
Distress or no distress, that's the question: A cutoff point for distress in a working population

PubMed Central

van Rhenen, Willem; van Dijk, Frank JH; Schaufeli, Wilmar B; Blonk, Roland WB

2008-01-01

Background The objective of the present study is to establish an optimal cutoff point for distress measured with the corresponding scale of the 4DSQ, using the prediction of sickness absence as a criterion. The cutoff point should result in a measure that can be used as a credible selection instrument for sickness absence in occupational health practice and in future studies on distress and mental disorders. Methods Distress is measured using the Four Dimensional Symptom Questionnaire (4DSQ), a 50-item self-report questionnaire, in a working population with and without sickness absence due to distress. Sensitivity and specificity were compared for various potential cutoff points, and a receiver operating characteristics analysis was conducted. Results and conclusion A distress cutoff point of ≥11 was defined. The choice was based on a challenging specificity and negative predictive value and indicates a distress level at which an employee is presumably at risk for subsequent sick leave on psychological grounds. The defined distress cutoff point is appropriate for use in occupational health practice and in studies of distress in working populations. PMID:18205912
Distress or no distress, that's the question: A cutoff point for distress in a working population.

PubMed

van Rhenen, Willem; van Dijk, Frank Jh; Schaufeli, Wilmar B; Blonk, Roland Wb

2008-01-18

The objective of the present study is to establish an optimal cutoff point for distress measured with the corresponding scale of the 4DSQ, using the prediction of sickness absence as a criterion. The cutoff point should result in a measure that can be used as a credible selection instrument for sickness absence in occupational health practice and in future studies on distress and mental disorders. Distress is measured using the Four Dimensional Symptom Questionnaire (4DSQ), a 50-item self-report questionnaire, in a working population with and without sickness absence due to distress. Sensitivity and specificity were compared for various potential cutoff points, and a receiver operating characteristics analysis was conducted. A distress cutoff point of >/=11 was defined. The choice was based on a challenging specificity and negative predictive value and indicates a distress level at which an employee is presumably at risk for subsequent sick leave on psychological grounds. The defined distress cutoff point is appropriate for use in occupational health practice and in studies of distress in working populations.
Kinetics of throwing arm joints and the trunk motion during an overarm distance throw by skilled Japanese elementary school boys.

PubMed

Kobayashi, Yasuto; Ae, Michiyoshi; Miyazaki, Akiyo; Fujii, Norihisa; Iiboshi, Akira; Nakatani, Hideki

2016-09-01

The purpose of this study was to investigate joint kinetics of the throwing arms and role of trunk motion in skilled elementary school boys during an overarm distance throw. Throwing motions of 42 boys from second, fourth, and sixth grade were videotaped with three high-speed cameras operating at 300 fps. Seven skilled boys from each grade were selected on the basis of throwing distance for three-dimensional kinetic analysis. Joint forces, torques, and torque powers of the throwing arm joints were calculated from reconstructed three-dimensional coordinate data smoothed at cut-off frequencies of 10.5-15 Hz and by the inverse dynamics method. Throwing distance and ball velocity significantly increased with school grade. The angular velocity of elbow extension before ball release increased with school grade, although no significant increase between the grades was observed in peak extension torque of elbow joint. The joint torque power of shoulder internal/external rotation tended to increase with school grade. When teaching the overarm throw, elementary school teachers should observe large backward twisting of trunk during the striding phase and should keep in mind that young children, such as second graders (age 8 years), will be unable to effectively utilise shoulder external/internal rotation during the throwing phase.
Two-temperature equilibration in warm dense hydrogen measured with x-ray scattering from the LCLS

NASA Astrophysics Data System (ADS)

Fletcher, Luke; High Energy Density Sciences Collaboration

2017-10-01

Understanding the properties of warm dense hydrogen plasmas is critical for modeling stellar and planetary interiors, as well as for inertial confinement fusion (ICF) experiments. Of central importance are the electron-ion collision and equilibration times that determine the microscopic properties in a high energy density state. Spectrally and angularly resolved x-ray scattering measurements from fs-laser heated hydrogen have resolved the picosecond evolution and energy relaxation from a two-temperature plasma towards thermodynamic equilibrium in the warm dense matter regime. The interaction of rapidly heated cryogenic hydrogen irradiated by a 400 nm, 5x1017 W/cm2 , 70 fs-laser is visualized with ultra-bright 5.5 kev x-ray pulses from the Linac Coherent Light (LCLS) source in 1 Hz repetition rate pump-probe setting. We demonstrate that the energy relaxation is faster than many classical binary collision theories that use ad hoc cutoff parameters used in the Landau-Spitzer determination of the Coulomb logarithm. This work was supported by the DOE Office of Science, Fusion Energy Science under contract No. SF00515 and supported under FWP 100182 and DOE Office of Basic Energy Sciences, Materials Sciences and Engineering Division, contract DE-AC02-76SF00515.
Parkinson's disease-cognitive rating scale: psychometrics for mild cognitive impairment.

PubMed

Fernández de Bobadilla, Ramón; Pagonabarraga, Javier; Martínez-Horta, Saül; Pascual-Sedano, Berta; Campolongo, Antonia; Kulisevsky, Jaime

2013-09-01

Lack of validated data on cutoff scores for mild cognitive impairment (MCI) and sensitivity to change in predementia stages of Parkinson's disease (PD) limit the utility of instruments measuring global cognition as screening and outcome measures in therapeutic trials. Investigators who were blinded to PD-Cognitive Rating Scale (PD-CRS) scores classified a cohort of prospectively recruited, nondemented patients into a PD with normal cognition (PD-NC) group and a PD with MCI (PD-MCI) group using Clinical Dementia Rating (CDR) and the Mattis Dementia Rating Scale-2 (MDRS-2). The discriminative power of the PD-CRS for PD-MCI was examined in a representative sample of 234 patients (145 in the PD-NC group; 89 in the PD-MCI group) and in a control group of 98 healthy individuals. Sensitivity to change in the PD-CRS score (the minimal clinically important difference was examined with the Clinical Global Impression of Change scale and was calculated with a combination of distribution-based and anchor-based approaches) was explored in a 6-month observational multicenter trial involving a subset of 120 patients (PD-NC, 63; PD-MCI, 57). Regression analysis demonstrated that PD-CRS total scores (P < 0.001) and age (P = 0.01) independently differentiated PD-NC from PD-MCI. Area under the receiver operating characteristic curve (AUC) analysis (AUC, 0.85; 95% confidence interval, 0.80-0.90) indicated that a score ≤ 81 of 134 was the optimal cutoff point on the total score for the PD-CRS (sensitivity, 79%; specificity, 80%; positive predictive value, 59%; negative predictive value, 91%). A range of change from 10 to 13 points on the PD-CRS total score was indicative of clinically significant change. These findings suggest that the PD-CRS is a useful tool to identify PD-MCI and to track cognitive changes in nondemented patients with PD. © 2013 International Parkinson and Movement Disorder Society.
Screening executive function and global cognition with the Nine-Card Sorting Test: healthy participant studies and ageing implications.

PubMed

Vigliecca, Nora Silvana; Baez, Sandra

2015-09-01

The Nine-Card Sorting Test provides valid and reliable scores when screening executive function, intelligence, and academic achievement. It is also useful for detecting cognitive impairment and dementia in the elderly and for assessing disease evolution and treatment effectiveness. It deals with three non-verbal sorting principles, individually and in pairs. The presence of risk in the ability to discover and organize visual logical stimuli is explored. This study aimed to describe performance on the Nine-Card Sorting Test in a non-clinical sample, to analyze the effect of demographic variables, and to propose suitable (i.e. the simplest and most homogeneous) cut-off points for possible deficits. Combinations in pairs (double arrays) were assessed (range: 0-3). Significant effects of age and education were observed, but no interactions among the demographic variables were seen. Differences between the second and third levels of education and between men and women were not significant. The simplest cut-off points were as follows: (i) the median for people younger than 45 years old was 2, independent of educational level; (ii) the median for people older than 74 years old was 1, independent of educational level; and (iii) the median for people aged 45-74 years old was 1 for the first level of education and 2 for higher levels of education. By considering both the statistical nature of the present dependent variable (number of completed categories) and the clear-cut performance of the different samples studied, this neuropsychological test can be defined as a categorical screening for executive function and global cognition. This is advantageous for reporting risk. Of the whole sample, the 25th percentile (score = 1) represented a valid index for possible deficits. Ageing questions are highlighted. The test is also fruitful for studies on visuospatial organization and its facilitatory and inhibitory mechanisms. © 2015 The Authors. Psychogeriatrics © 2015 Japanese Psychogeriatric Society.
Predictive accuracy of risk scales following self-harm: multicentre, prospective cohort study†

PubMed Central

Quinlivan, Leah; Cooper, Jayne; Meehan, Declan; Longson, Damien; Potokar, John; Hulme, Tom; Marsden, Jennifer; Brand, Fiona; Lange, Kezia; Riseborough, Elena; Page, Lisa; Metcalfe, Chris; Davies, Linda; O'Connor, Rory; Hawton, Keith; Gunnell, David; Kapur, Nav

2017-01-01

Background Scales are widely used in psychiatric assessments following self-harm. Robust evidence for their diagnostic use is lacking. Aims To evaluate the performance of risk scales (Manchester Self-Harm Rule, ReACT Self-Harm Rule, SAD PERSONS scale, Modified SAD PERSONS scale, Barratt Impulsiveness Scale); and patient and clinician estimates of risk in identifying patients who repeat self-harm within 6 months. Method A multisite prospective cohort study was conducted of adults aged 18 years and over referred to liaison psychiatry services following self-harm. Scale a priori cut-offs were evaluated using diagnostic accuracy statistics. The area under the curve (AUC) was used to determine optimal cut-offs and compare global accuracy. Results In total, 483 episodes of self-harm were included in the study. The episode-based 6-month repetition rate was 30% (n = 145). Sensitivity ranged from 1% (95% CI 0–5) for the SAD PERSONS scale, to 97% (95% CI 93–99) for the Manchester Self-Harm Rule. Positive predictive values ranged from 13% (95% CI 2–47) for the Modified SAD PERSONS Scale to 47% (95% CI 41–53) for the clinician assessment of risk. The AUC ranged from 0.55 (95% CI 0.50–0.61) for the SAD PERSONS scale to 0.74 (95% CI 0.69–0.79) for the clinician global scale. The remaining scales performed significantly worse than clinician and patient estimates of risk (P<0.001). Conclusions Risk scales following self-harm have limited clinical utility and may waste valuable resources. Most scales performed no better than clinician or patient ratings of risk. Some performed considerably worse. Positive predictive values were modest. In line with national guidelines, risk scales should not be used to determine patient management or predict self-harm. PMID:28302702
Predictive accuracy of risk scales following self-harm: multicentre, prospective cohort study.

PubMed

Quinlivan, Leah; Cooper, Jayne; Meehan, Declan; Longson, Damien; Potokar, John; Hulme, Tom; Marsden, Jennifer; Brand, Fiona; Lange, Kezia; Riseborough, Elena; Page, Lisa; Metcalfe, Chris; Davies, Linda; O'Connor, Rory; Hawton, Keith; Gunnell, David; Kapur, Nav

2017-06-01

Background Scales are widely used in psychiatric assessments following self-harm. Robust evidence for their diagnostic use is lacking. Aims To evaluate the performance of risk scales (Manchester Self-Harm Rule, ReACT Self-Harm Rule, SAD PERSONS scale, Modified SAD PERSONS scale, Barratt Impulsiveness Scale); and patient and clinician estimates of risk in identifying patients who repeat self-harm within 6 months. Method A multisite prospective cohort study was conducted of adults aged 18 years and over referred to liaison psychiatry services following self-harm. Scale a priori cut-offs were evaluated using diagnostic accuracy statistics. The area under the curve (AUC) was used to determine optimal cut-offs and compare global accuracy. Results In total, 483 episodes of self-harm were included in the study. The episode-based 6-month repetition rate was 30% ( n = 145). Sensitivity ranged from 1% (95% CI 0-5) for the SAD PERSONS scale, to 97% (95% CI 93-99) for the Manchester Self-Harm Rule. Positive predictive values ranged from 13% (95% CI 2-47) for the Modified SAD PERSONS Scale to 47% (95% CI 41-53) for the clinician assessment of risk. The AUC ranged from 0.55 (95% CI 0.50-0.61) for the SAD PERSONS scale to 0.74 (95% CI 0.69-0.79) for the clinician global scale. The remaining scales performed significantly worse than clinician and patient estimates of risk ( P <0.001). Conclusions Risk scales following self-harm have limited clinical utility and may waste valuable resources. Most scales performed no better than clinician or patient ratings of risk. Some performed considerably worse. Positive predictive values were modest. In line with national guidelines, risk scales should not be used to determine patient management or predict self-harm. © The Royal College of Psychiatrists 2017.
On the gas-phase formation of the HCO radical: accurate quantum study of the H+CO radiative association

NASA Astrophysics Data System (ADS)

Stoecklin, Thierry; Halvick, Philippe; Yu, Hua-Gen; Nyman, Gunnar; Ellinger, Yves

2018-04-01

We present the first quantum study of the radiative association of H and CO to form the HCO molecule within a time-independent approach. We use a recently published 3D potential energy surface of spectroscopic accuracy and two 3D dipole moment surfaces, which were calculated for this study. We discuss the variation of the radiative association cross-section as a function of both the rotational angular momentum of CO and the total angular momentum and use the uniform J-shifting approach to obtain the global radiative association rate coefficient. The effect of the saddle point separating the HCO molecule from the H+CO reactants and the main features of the radiative association cross-sections are analysed and discussed. The calculated rate coefficient is below 10-23 cm3 molecule-1 s-1 for temperatures lower than 30 K, and increases up to 5 × 10-20 cm3 molecule-1 s-1 at T = 300 K. These results demonstrate that the gas-phase H+CO radiative association cannot be the process at the origin of the sequence leading to the formation of methanol in a cold interstellar medium.

Improving the realism of white matter numerical phantoms: a step towards a better understanding of the influence of structural disorders in diffusion MRI

NASA Astrophysics Data System (ADS)

Ginsburger, Kévin; Poupon, Fabrice; Beaujoin, Justine; Estournet, Delphine; Matuschke, Felix; Mangin, Jean-François; Axer, Markus; Poupon, Cyril

2018-02-01

White matter is composed of irregularly packed axons leading to a structural disorder in the extra-axonal space. Diffusion MRI experiments using oscillating gradient spin echo sequences have shown that the diffusivity transverse to axons in this extra-axonal space is dependent on the frequency of the employed sequence. In this study, we observe the same frequency-dependence using 3D simulations of the diffusion process in disordered media. We design a novel white matter numerical phantom generation algorithm which constructs biomimicking geometric configurations with few design parameters, and enables to control the level of disorder of the generated phantoms. The influence of various geometrical parameters present in white matter, such as global angular dispersion, tortuosity, presence of Ranvier nodes, beading, on the extra-cellular perpendicular diffusivity frequency dependence was investigated by simulating the diffusion process in numerical phantoms of increasing complexity and fitting the resulting simulated diffusion MR signal attenuation with an adequate analytical model designed for trapezoidal OGSE sequences. This work suggests that angular dispersion and especially beading have non-negligible effects on this extracellular diffusion metrics that may be measured using standard OGSE DW-MRI clinical protocols.
Tomographic imaging using poissonian detector data

DOEpatents

Aspelmeier, Timo; Ebel, Gernot; Hoeschen, Christoph

2013-10-15

An image reconstruction method for reconstructing a tomographic image (f.sub.j) of a region of investigation within an object (1), comprises the steps of providing detector data (y.sub.i) comprising Poisson random values measured at an i-th of a plurality of different positions, e.g. i=(k,l) with pixel index k on a detector device and angular index l referring to both the angular position (.alpha..sub.l) and the rotation radius (r.sub.l) of the detector device (10) relative to the object (1), providing a predetermined system matrix A.sub.ij assigning a j-th voxel of the object (1) to the i-th detector data (y.sub.i), and reconstructing the tomographic image (f.sub.j) based on the detector data (y.sub.i), said reconstructing step including a procedure of minimizing a functional F(f) depending on the detector data (y.sub.i) and the system matrix A.sub.ij and additionally including a sparse or compressive representation of the object (1) in an orthobasis T, wherein the tomographic image (f.sub.j) represents the global minimum of the functional F(f). Furthermore, an imaging method and an imaging device using the image reconstruction method are described.
Video Altimeter and Obstruction Detector for an Aircraft

NASA Technical Reports Server (NTRS)

Delgado, Frank J.; Abernathy, Michael F.; White, Janis; Dolson, William R.

2013-01-01

Video-based altimetric and obstruction detection systems for aircraft have been partially developed. The hardware of a system of this type includes a downward-looking video camera, a video digitizer, a Global Positioning System receiver or other means of measuring the aircraft velocity relative to the ground, a gyroscope based or other attitude-determination subsystem, and a computer running altimetric and/or obstruction-detection software. From the digitized video data, the altimetric software computes the pixel velocity in an appropriate part of the video image and the corresponding angular relative motion of the ground within the field of view of the camera. Then by use of trigonometric relationships among the aircraft velocity, the attitude of the camera, the angular relative motion, and the altitude, the software computes the altitude. The obstruction-detection software performs somewhat similar calculations as part of a larger task in which it uses the pixel velocity data from the entire video image to compute a depth map, which can be correlated with a terrain map, showing locations of potential obstructions. The depth map can be used as real-time hazard display and/or to update an obstruction database.
Residue-level global and local ensemble-ensemble comparisons of protein domains.

PubMed

Clark, Sarah A; Tronrud, Dale E; Karplus, P Andrew

2015-09-01

Many methods of protein structure generation such as NMR-based solution structure determination and template-based modeling do not produce a single model, but an ensemble of models consistent with the available information. Current strategies for comparing ensembles lose information because they use only a single representative structure. Here, we describe the ENSEMBLATOR and its novel strategy to directly compare two ensembles containing the same atoms to identify significant global and local backbone differences between them on per-atom and per-residue levels, respectively. The ENSEMBLATOR has four components: eePREP (ee for ensemble-ensemble), which selects atoms common to all models; eeCORE, which identifies atoms belonging to a cutoff-distance dependent common core; eeGLOBAL, which globally superimposes all models using the defined core atoms and calculates for each atom the two intraensemble variations, the interensemble variation, and the closest approach of members of the two ensembles; and eeLOCAL, which performs a local overlay of each dipeptide and, using a novel measure of local backbone similarity, reports the same four variations as eeGLOBAL. The combination of eeGLOBAL and eeLOCAL analyses identifies the most significant differences between ensembles. We illustrate the ENSEMBLATOR's capabilities by showing how using it to analyze NMR ensembles and to compare NMR ensembles with crystal structures provides novel insights compared to published studies. One of these studies leads us to suggest that a "consistency check" of NMR-derived ensembles may be a useful analysis step for NMR-based structure determinations in general. The ENSEMBLATOR 1.0 is available as a first generation tool to carry out ensemble-ensemble comparisons. © 2015 The Protein Society.
Residue-level global and local ensemble-ensemble comparisons of protein domains

PubMed Central

Clark, Sarah A; Tronrud, Dale E; Andrew Karplus, P

2015-01-01

Many methods of protein structure generation such as NMR-based solution structure determination and template-based modeling do not produce a single model, but an ensemble of models consistent with the available information. Current strategies for comparing ensembles lose information because they use only a single representative structure. Here, we describe the ENSEMBLATOR and its novel strategy to directly compare two ensembles containing the same atoms to identify significant global and local backbone differences between them on per-atom and per-residue levels, respectively. The ENSEMBLATOR has four components: eePREP (ee for ensemble-ensemble), which selects atoms common to all models; eeCORE, which identifies atoms belonging to a cutoff-distance dependent common core; eeGLOBAL, which globally superimposes all models using the defined core atoms and calculates for each atom the two intraensemble variations, the interensemble variation, and the closest approach of members of the two ensembles; and eeLOCAL, which performs a local overlay of each dipeptide and, using a novel measure of local backbone similarity, reports the same four variations as eeGLOBAL. The combination of eeGLOBAL and eeLOCAL analyses identifies the most significant differences between ensembles. We illustrate the ENSEMBLATOR's capabilities by showing how using it to analyze NMR ensembles and to compare NMR ensembles with crystal structures provides novel insights compared to published studies. One of these studies leads us to suggest that a “consistency check” of NMR-derived ensembles may be a useful analysis step for NMR-based structure determinations in general. The ENSEMBLATOR 1.0 is available as a first generation tool to carry out ensemble-ensemble comparisons. PMID:26032515
Scaling a Convection-Resolving RCM to Near-Global Scales

NASA Astrophysics Data System (ADS)

Leutwyler, D.; Fuhrer, O.; Chadha, T.; Kwasniewski, G.; Hoefler, T.; Lapillonne, X.; Lüthi, D.; Osuna, C.; Schar, C.; Schulthess, T. C.; Vogt, H.

2017-12-01

In the recent years, first decade-long kilometer-scale resolution RCM simulations have been performed on continental-scale computational domains. However, the size of the planet Earth is still an order of magnitude larger and thus the computational implications of performing global climate simulations at this resolution are challenging. We explore the gap between the currently established RCM simulations and global simulations by scaling the GPU accelerated version of the COSMO model to a near-global computational domain. To this end, the evolution of an idealized moist baroclinic wave has been simulated over the course of 10 days with a grid spacing of up to 930 m. The computational mesh employs 36'000 x 16'001 x 60 grid points and covers 98.4% of the planet's surface. The code shows perfect weak scaling up to 4'888 Nodes of the Piz Daint supercomputer and yields 0.043 simulated years per day (SYPD) which is approximately one seventh of the 0.2-0.3 SYPD required to conduct AMIP-type simulations. However, at half the resolution (1.9 km) we've observed 0.23 SYPD. Besides formation of frontal precipitating systems containing embedded explicitly-resolved convective motions, the simulations reveal a secondary instability that leads to cut-off warm-core cyclonic vortices in the cyclone's core, once the grid spacing is refined to the kilometer scale. The explicit representation of embedded moist convection and the representation of the previously unresolved instabilities exhibit a physically different behavior in comparison to coarser-resolution simulations. The study demonstrates that global climate simulations using kilometer-scale resolution are imminent and serves as a baseline benchmark for global climate model applications and future exascale supercomputing systems.
Optimal cutoffs of obesity measures in relation to cancer risk in postmenopausal women in the Women's Health Initiative Study.

PubMed

Heo, Moonseong; Kabat, Geoffrey C; Strickler, Howard D; Lin, Juan; Hou, Lifang; Stefanick, Marcia L; Anderson, Garnet L; Rohan, Thomas E

2015-03-01

Obesity is a risk factor for several cancers in postmenopausal women. We attempted to determine cutoffs of adiposity measures in relation to risk of obesity-related cancers among postmenopausal women and to examine the effects of hormone therapy (HT) use on the cutoffs, neither of which has been broadly studied. We used data from the Women's Health Initiative cohort (n=144,701) and applied Cox-proportional hazards regressions to each combination of 17 cancer types and 6 anthropometric measures (weight, body mass index [BMI], weight to height ratio, waist circumference, waist to hip ratio [WHR], and waist to height ratio). Interactions between the anthropometric measures and HT use were also examined. Cutoffs were determined by applying a grid search followed by a two-fold cross validation method. Survival ROC analysis of 5- and 10-year incidence followed. Breast, colorectal, colon, endometrium, kidney, and all cancers combined were significantly positively associated with all six anthropometric measures, whereas lung cancer among ever smokers was significantly inversely associated with all measures except WHR. The derived cutoffs of each obesity measure varied across cancers (e.g., BMI cutoffs for breast and endometrium cancers were 30 kg/m(2) and 34 kg/m(2), respectively), and also depended on HT use. The Youden indices of the cutoffs for predicting 5- and 10-year cancer incidence were higher among HT never users. Using a panel of different anthropometric measures, we derived optimal cut-offs categorizing populations into high- and low-risk groups, which differed by cancer type and HT use. Although the discrimination abilities of these risk categories were generally poor, the results of this study could serve as a starting point from which to determine adiposity cutoffs for inclusion in risk prediction models for specific cancer types.
Whole-body angular momentum during stair ascent and descent.

PubMed

Silverman, Anne K; Neptune, Richard R; Sinitski, Emily H; Wilken, Jason M

2014-04-01

The generation of whole-body angular momentum is essential in many locomotor tasks and must be regulated in order to maintain dynamic balance. However, angular momentum has not been investigated during stair walking, which is an activity that presents a biomechanical challenge for balance-impaired populations. We investigated three-dimensional whole-body angular momentum during stair ascent and descent and compared it to level walking. Three-dimensional body-segment kinematic and ground reaction force (GRF) data were collected from 30 healthy subjects. Angular momentum was calculated using a 13-segment whole-body model. GRFs, external moment arms and net joint moments were used to interpret the angular momentum results. The range of frontal plane angular momentum was greater for stair ascent relative to level walking. In the transverse and sagittal planes, the range of angular momentum was smaller in stair ascent and descent relative to level walking. Significant differences were also found in the ground reaction forces, external moment arms and net joint moments. The sagittal plane angular momentum results suggest that individuals alter angular momentum to effectively counteract potential trips during stair ascent, and reduce the range of angular momentum to avoid falling forward during stair descent. Further, significant differences in joint moments suggest potential neuromuscular mechanisms that account for the differences in angular momentum between walking conditions. These results provide a baseline for comparison to impaired populations that have difficulty maintaining dynamic balance, particularly during stair ascent and descent. Copyright © 2014 Elsevier B.V. All rights reserved.
Upper and lower bounds for the speed of pulled fronts with a cut-off

NASA Astrophysics Data System (ADS)

Benguria, R. D.; Depassier, M. C.; Loss, M.

2008-02-01

We establish rigorous upper and lower bounds for the speed of pulled fronts with a cut-off. For all reaction terms of KPP type a simple analytic upper bound is given. The lower bounds however depend on details of the reaction term. For a small cut-off parameter the two leading order terms in the asymptotic expansion of the upper and lower bounds coincide and correspond to the Brunet-Derrida formula. For large cut-off parameters the bounds do not coincide and permit a simple estimation of the speed of the front.
Natural Covariant Planck Scale Cutoffs and the Cosmic Microwave Background Spectrum.

PubMed

Chatwin-Davies, Aidan; Kempf, Achim; Martin, Robert T W

2017-07-21

We calculate the impact of quantum gravity-motivated ultraviolet cutoffs on inflationary predictions for the cosmic microwave background spectrum. We model the ultraviolet cutoffs fully covariantly to avoid possible artifacts of covariance breaking. Imposing these covariant cutoffs results in the production of small, characteristically k-dependent oscillations in the spectrum. The size of the effect scales linearly with the ratio of the Planck to Hubble lengths during inflation. Consequently, the relative size of the effect could be as large as one part in 10^{5}; i.e., eventual observability may not be ruled out.
A proposed measurement of optical orbital and spin angular momentum and its implications for photon angular momentum

NASA Astrophysics Data System (ADS)

Leader, Elliot

2018-04-01

The expression for the total angular momentum carried by a laser optical vortex beam, splits, in the paraxial approximation, into two terms which seem to represent orbital and spin angular momentum respectively. There are, however, two very different competing versions of the formula for the spin angular momentum, one based on the use of the Poynting vector, as in classical electrodynamics, the other related to the canonical expression for the angular momentum which occurs in Quantum Electrodynamics. I analyze the possibility that a sufficiently sensitive optical measurement could decide which of these corresponds to the actual physical angular momentum carried by the beam.
A Computational Technique to Determine the Angular Displacement, Velocity and Momentum of a Human Body.

ERIC Educational Resources Information Center

Hay, James G.; Wilson, Barry D.

The angular momentum of a human body derived from both the angular velocity and angular displacement, utilizing cinematographic records has not been adequately assessed, prior to this study. Miller (1970) obtained the angular momentum but only during the airborne phase of activity. The method used by Ramey (1973) involved a force platform, but…
Difference in perception of angular displacement according to applied waveforms.

PubMed

Kushiro, Keisuke; Goto, Fumiyuki

2013-05-01

This study shows that the differences in the waveforms of angular rotation affect the perception and memory of angular displacement. During daily life, when we turn our head during various activities, our brain calculates how much angular displacement our head has undergone. However, how we obtain an accurate estimation of this angular displacement remains unclarified. This study aims to clarify this issue by investigating the perception and memory of passive rotation for three different waveforms of angular velocity rotation (sinusoidal (sine), triangle, and step). Thirteen healthy young subjects sitting on a servo-controlled chair were passively rotated at 60° or 120° about the earth-vertical axis by using one of these three angular velocity waveforms. They then attempted to reproduce the rotation angle by rotating the chair in the same direction in which they had been passively rotated using a handheld controller. The gain (reproduced angle/passively rotated angle) was calculated and used for the evaluation of the perception and memory of angular rotation. The gain for step rotation was larger than that for sine and triangle rotations, with statistical significance. This confirms that the difference in the waveforms of angular rotation affects the perception and memory of angular displacement.
Influence of presence/absence of thyroid gland on the cutoff value for thyroglobulin in lymph-node aspiration to detect metastatic papillary thyroid carcinoma.

PubMed

Zhao, Huan; Wang, Yong; Wang, Min-Jie; Zhang, Zhi-Hui; Wang, Hai-Rui; Zhang, Bing; Guo, Hui-Qin

2017-04-28

Thyroglobulin measurement with fine-needle aspiration (Tg-FNA) is a sensitive method for detecting metastatic papillary thyroid carcinoma (PTC). However, the diagnostic threshold is not well established and the influence of the thyroid gland on the cutoff value is also controversial. In this study, patients were classified into two groups according to the presence or absence of thyroid tissue, to determine an appropriate cutoff value for clinical practice. Patients with a history of thyroid nodules or surgery for PTC and with enlarged cervical lymph nodes on an FNA examination were enrolled for Tg-FNA detection. One hundred ninety-six lymph nodes (189 patients) were included: 100 from preoperative patients, 49 from patients treated with partial thyroid ablation, and 47 from patients with total thyroid ablation. In 149 lymph nodes from patient with thyroids, the cutoff value for Tg-FNA was 55.99 ng/mL (sensitivity, 95.1%; specificity, 100%), whereas in 47 lymph nodes from patients without a thyroid, it was 9.71 ng/mL (sensitivity, 96.7%; specificity, 100%). Thus, the cutoff value for Tg-FNA was higher in patients with thyroids than in patients without thyroids. The cutoff value for Tg-FNA is influenced by residual thyroid tissue, and a higher cutoff value is recommended for patients with thyroids than for patients without thyroids.
Anisotropic strong-coupling effects on superfluid 3He in aerogels: Conventional spin-fluctuation approach

NASA Astrophysics Data System (ADS)

Ikeda, Ryusuke

2015-05-01

Motivated by recent experiments on liquid 3He reporting emergence of novel superfluid phases in globally anisotropic aerogels, our previous theory on superfluid 3He in globally anisotropic aerogels is extended to incorporate the effects of anisotropy of the quasiparticle scattering cross section on the strong-coupling (SC) contributions to the Ginzburg-Landau (GL) free energy on the basis of the spin-fluctuation (paramagnon) approach to the SC contributions developed by Brinkman et al. [Phys. Rev. A 10, 2386 (1974), 10.1103/PhysRevA.10.2386]. In the globally isotropic case, impurity effects on the SC correction destabilize the A phase even at higher pressures of about 30 bar and make the B phase the only state in equilibrium, while SC contributions accompanied by a global stretched anisotropy to the GL quartic terms generally tend to broaden the stability region of the A phase compared with that of the B phase. In particular, in contrast to the cases in bulk and in the isotropic aerogel, the SC corrections to the GL quadratic terms are not negligible in the globally anisotropic case but may change the sign of the apparent anisotropy depending on the magnitude of the frequency cutoff of the normal paramagnon propagator. Based on this sign change of the apparent anisotropy, we discuss different strange observations on superfluid 3He in porous media such as the disappearance of the polar superfluid phase at higher pressures seen in nematically ordered aerogels and the absence of B and A phases with planar l ̂ vector in a stretched aerogel.
10 CFR 26.133 - Cutoff levels for drugs and drug metabolites.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Cutoff levels for drugs and drug metabolites. 26.133 Section 26.133 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Licensee Testing Facilities § 26.133 Cutoff levels for drugs and drug metabolites. Subject to the provisions of § 26.31(d)(3)(iii...
10 CFR 26.133 - Cutoff levels for drugs and drug metabolites.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Cutoff levels for drugs and drug metabolites. 26.133 Section 26.133 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Licensee Testing Facilities § 26.133 Cutoff levels for drugs and drug metabolites. Subject to the provisions of § 26.31(d)(3)(iii...
CONNECTING ANGULAR MOMENTUM AND GALACTIC DYNAMICS: THE COMPLEX INTERPLAY BETWEEN SPIN, MASS, AND MORPHOLOGY

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

Teklu, Adelheid F.; Remus, Rhea-Silvia; Dolag, Klaus

The evolution and distribution of the angular momentum of dark matter (DM) halos have been discussed in several studies over the past decades. In particular, the idea arose that angular momentum conservation should allow us to infer the total angular momentum of the entire DM halo from measuring the angular momentum of the baryonic component, which is populating the center of the halo, especially for disk galaxies. To test this idea and to understand the connection between the angular momentum of the DM halo and its galaxy, we use a state-of-the-art, hydrodynamical cosmological simulation taken from the set of Magneticummore » Pathfinder simulations. Thanks to the inclusion of the relevant physical processes, the improved underlying numerical methods, and high spatial resolution, we successfully produce populations of spheroidal and disk galaxies self-consistently. Thus, we are able to study the dependence of galactic properties on their morphology. We find that (1) the specific angular momentum of stars in disk and spheroidal galaxies as a function of their stellar mass compares well with observational results; (2) the specific angular momentum of the stars in disk galaxies is slightly smaller compared to the specific angular momentum of the cold gas, in good agreement with observations; (3) simulations including the baryonic component show a dichotomy in the specific stellar angular momentum distribution when splitting the galaxies according to their morphological type (this dichotomy can also be seen in the spin parameter, where disk galaxies populate halos with slightly larger spin compared to spheroidal galaxies); (4) disk galaxies preferentially populate halos in which the angular momentum vector of the DM component in the central part shows a better alignment to the angular momentum vector of the entire halo; and (5) the specific angular momentum of the cold gas in disk galaxies is approximately 40% smaller than the specific angular momentum of the total DM halo and shows a significant scatter.« less
To the horizon and beyond: Weak lensing of the CMB and binary inspirals into horizonless objects

NASA Astrophysics Data System (ADS)

Kesden, Michael

This thesis examines two predictions of general relativity: weak lensing and gravitational waves. The cosmic microwave background (CMB) is gravitationally lensed by the large-scale structure between the observer and the last- scattering surface. This weak lensing induces non-Gaussian correlations that can be used to construct estimators for the deflection field. The error and bias of these estimators are derived and used to analyze the viability of lensing reconstruction for future CMB experiments. Weak lensing also affects the one-point probability distribution function of the CMB. The skewness and kurtosis induced by lensing and the Sunayev- Zel'dovich (SZ) effect are calculated as functions of the angular smoothing scale of the map. While these functions offer the advantage of easy computability, only the skewness from lensing-SZ correlations can potentially be detected, even in the limit of the largest amplitude fluctuations allowed by observation. Lensing estimators are also essential to constrain inflation, the favored explanation for large-scale isotropy and the origin of primordial perturbations. B-mode polarization is considered to be a "smoking-gun" signature of inflation, and lensing estimators can be used to recover primordial B-modes from lensing-induced contamination. The ability of future CMB experiments to constrain inflation is assessed as functions of survey size and instrumental sensitivity. A final application of lensing estimators is to constrain a possible cutoff in primordial density perturbations on near-horizon scales. The paucity of independent modes on such scales limits the statistical certainty of such a constraint. Measurements of the deflection field can be used to constrain at the 3s level the existence of a cutoff large enough to account for current CMB observations. A final chapter of this thesis considers an independent topic: the gravitational-wave (GW) signature of a binary inspiral into a horizonless object. If the supermassive objects at galactic centers lack the horizons of traditional black holes, inspiraling objects could emit GWs after passing within their surfaces. The GWs produced by such an inspiral are calculated, revealing distinctive features potentially observable by future GW observatories.
Comparing HARPS and Kepler surveys. The alignment of multiple-planet systems

NASA Astrophysics Data System (ADS)

Figueira, P.; Marmier, M.; Boué, G.; Lovis, C.; Santos, N. C.; Montalto, M.; Udry, S.; Pepe, F.; Mayor, M.

2012-05-01

Context. The recent results of the HARPS and Kepler surveys provided us with a bounty of extrasolar systems. While the two teams extensively analyzed each of their data-sets, little work has been done comparing the two. Aims: We study a subset of the planetary population whose characterization is simultaneously within reach of both instruments. We compare the statistical properties of planets in systems with msini > 5-10 M⊕ and R > 2 R⊕, as inferred from the HARPS and Kepler surveys, respectively. If we assume that the underlying population has the same characteristics, the different detection sensitivity to the orbital inclination relative to the line of sight allows us to probe the planets' mutual inclination. Methods: We considered the frequency of systems with one, two, and three planets as dictated by HARPS data. We used Kepler's planetary period and host mass and radius distributions (corrected from detection bias) to model planetary systems in a simple, yet physically plausible way. We then varied the mutual inclination between planets in a system according to different prescriptions (completely aligned, Rayleigh distributions, and isotropic) and compared the transit frequencies with one, two, or three planets with those measured by Kepler. Results: The results show that the two datasets are compatible, a remarkable result especially because there are no tunable knobs other than the assumed inclination distribution. For msini cutoffs of 7-10 M⊕, which are those expected to correspond to the radius cutoff of 2 R⊕, we conclude that the results are better described by a Rayleigh distribution with a mode of 1° or smaller. We show that the best-fit scenario only becomes a Rayleigh distribution with a mode of 5° if we assume a quite extreme mass-radius relationship for the planetary population. Conclusions: These results have important consequences for our understanding of the role of several proposed formation and evolution mechanisms. They confirm that planets are likely to have been formed in a disk and show that most planetary systems evolve quietly without strong angular momentum exchanges such as those produced by Kozai mechanism or planet scattering.

The Ocean Gene Atlas: exploring the biogeography of plankton genes online.

PubMed

Villar, Emilie; Vannier, Thomas; Vernette, Caroline; Lescot, Magali; Cuenca, Miguelangel; Alexandre, Aurélien; Bachelerie, Paul; Rosnet, Thomas; Pelletier, Eric; Sunagawa, Shinichi; Hingamp, Pascal

2018-05-21

The Ocean Gene Atlas is a web service to explore the biogeography of genes from marine planktonic organisms. It allows users to query protein or nucleotide sequences against global ocean reference gene catalogs. With just one click, the abundance and location of target sequences are visualized on world maps as well as their taxonomic distribution. Interactive results panels allow for adjusting cutoffs for alignment quality and displaying the abundances of genes in the context of environmental features (temperature, nutrients, etc.) measured at the time of sampling. The ease of use enables non-bioinformaticians to explore quantitative and contextualized information on genes of interest in the global ocean ecosystem. Currently the Ocean Gene Atlas is deployed with (i) the Ocean Microbial Reference Gene Catalog (OM-RGC) comprising 40 million non-redundant mostly prokaryotic gene sequences associated with both Tara Oceans and Global Ocean Sampling (GOS) gene abundances and (ii) the Marine Atlas of Tara Ocean Unigenes (MATOU) composed of >116 million eukaryote unigenes. Additional datasets will be added upon availability of further marine environmental datasets that provide the required complement of sequence assemblies, raw reads and contextual environmental parameters. Ocean Gene Atlas is a freely-available web service at: http://tara-oceans.mio.osupytheas.fr/ocean-gene-atlas/.
On Increasing Network Lifetime in Body Area Networks Using Global Routing with Energy Consumption Balancing

PubMed Central

Tsouri, Gill R.; Prieto, Alvaro; Argade, Nikhil

2012-01-01

Global routing protocols in wireless body area networks are considered. Global routing is augmented with a novel link cost function designed to balance energy consumption across the network. The result is a substantial increase in network lifetime at the expense of a marginal increase in energy per bit. Network maintenance requirements are reduced as well, since balancing energy consumption means all batteries need to be serviced at the same time and less frequently. The proposed routing protocol is evaluated using a hardware experimental setup comprising multiple nodes and an access point. The setup is used to assess network architectures, including an on-body access point and an off-body access point with varying number of antennas. Real-time experiments are conducted in indoor environments to assess performance gains. In addition, the setup is used to record channel attenuation data which are then processed in extensive computer simulations providing insight on the effect of protocol parameters on performance. Results demonstrate efficient balancing of energy consumption across all nodes, an average increase of up to 40% in network lifetime corresponding to a modest average increase of 0.4 dB in energy per bit, and a cutoff effect on required transmission power to achieve reliable connectivity. PMID:23201987
On increasing network lifetime in body area networks using global routing with energy consumption balancing.

PubMed

Tsouri, Gill R; Prieto, Alvaro; Argade, Nikhil

2012-09-26

Global routing protocols in wireless body area networks are considered. Global routing is augmented with a novel link cost function designed to balance energy consumption across the network. The result is a substantial increase in network lifetime at the expense of a marginal increase in energy per bit. Network maintenance requirements are reduced as well, since balancing energy consumption means all batteries need to be serviced at the same time and less frequently. The proposed routing protocol is evaluated using a hardware experimental setup comprising multiple nodes and an access point. The setup is used to assess network architectures, including an on-body access point and an off-body access point with varying number of antennas. Real-time experiments are conducted in indoor environments to assess performance gains. In addition, the setup is used to record channel attenuation data which are then processed in extensive computer simulations providing insight on the effect of protocol parameters on performance. Results demonstrate efficient balancing of energy consumption across all nodes, an average increase of up to 40% in network lifetime corresponding to a modest average increase of 0.4 dB in energy per bit, and a cutoff effect on required transmission power to achieve reliable connectivity.
Posttraumatic stress disorder among refugees: Measurement invariance of Harvard Trauma Questionnaire scores across global regions and response patterns.

PubMed

Rasmussen, Andrew; Verkuilen, Jay; Ho, Emily; Fan, Yuyu

2015-12-01

Despite the central role of posttraumatic stress disorder (PTSD) in international humanitarian aid work, there has been little examination of the measurement invariance of PTSD measures across culturally defined refugee subgroups. This leaves mental health workers in disaster settings with little to support inferences made using the results of standard clinical assessment tools, such as the severity of symptoms and prevalence rates. We examined measurement invariance in scores from the most widely used PTSD measure in refugee populations, the Harvard Trauma Questionnaire (HTQ; Mollica et al., 1992), in a multinational and multilingual sample of asylum seekers from 81 countries of origin in 11 global regions. Clustering HTQ responses to justify grouping regional groups by response patterns resulted in 3 groups for testing measurement invariance: West Africans, Himalayans, and all others. Comparing log-likelihood ratios showed that while configural invariance seemed to hold, metric and scalar invariance did not. These findings call into question the common practice of using standard cut-off scores on PTSD measures across culturally dissimilar refugee populations. In addition, high correlation between factors suggests that the construct validity of scores from North American and European measures of PTSD may not hold globally. (c) 2015 APA, all rights reserved).
Optical angular momentum and atoms

PubMed Central

2017-01-01

Any coherent interaction of light and atoms needs to conserve energy, linear momentum and angular momentum. What happens to an atom’s angular momentum if it encounters light that carries orbital angular momentum (OAM)? This is a particularly intriguing question as the angular momentum of atoms is quantized, incorporating the intrinsic spin angular momentum of the individual electrons as well as the OAM associated with their spatial distribution. In addition, a mechanical angular momentum can arise from the rotation of the entire atom, which for very cold atoms is also quantized. Atoms therefore allow us to probe and access the quantum properties of light’s OAM, aiding our fundamental understanding of light–matter interactions, and moreover, allowing us to construct OAM-based applications, including quantum memories, frequency converters for shaped light and OAM-based sensors. This article is part of the themed issue ‘Optical orbital angular momentum’. PMID:28069766
Vibration signal correction of unbalanced rotor due to angular speed fluctuation

NASA Astrophysics Data System (ADS)

Cao, Hongrui; He, Dong; Xi, Songtao; Chen, Xuefeng

2018-07-01

The rotating speed of a rotor is hardly constant in practice due to angular speed fluctuation, which affects the balancing accuracy of the rotor. In this paper, the effect of angular speed fluctuation on vibration responses of the unbalanced rotor is analyzed quantitatively. Then, a vibration signal correction method based on zoom synchrosqueezing transform (ZST) and tacholess order tracking is proposed. The instantaneous angular speed (IAS) of the rotor is extracted by the ZST firstly and then used to calculate the instantaneous phase. The vibration signal is further resampled in angular domain to reduce the effect of angular speed fluctuation. The signal obtained in angular domain is transformed into order domain using discrete Fourier transform (DFT) to estimate the amplitude and phase of the vibration signal. Simulated and experimental results show that the proposed method can successfully correct the amplitude and phase of the vibration signal due to angular speed fluctuation.
Revisiting the Phadia/EliA cut-off values for anticardiolipin and anti-β2-glycoprotein I antibodies: a systematic evaluation according to the guidelines.

PubMed

Bor, M V; Jacobsen, I-L Søtang; Gram, J B; Sidelmann, J J

2018-01-01

Background Phadia/EliA fluorescence enzyme immunoassays are widely used automated assays for anticardiolipin (aCL) and anti-β2-glycoprotein I (aβ2GPI) antibodies. To date, cut-off values for these assays have not been evaluated systematically and the evidence behind manufacturer's recommended cut-off values is not clear. Objective To determine Phadia/EliA cut-off values for antiphospholipid antibodies (aPL) according to the procedures suggested by guidelines. Methods A total of 266 blood donors (135 females and 131 males) were included. The pre-handling and analysis of the samples were performed according to the International Society on Thrombosis and Hemostasis (ISTH) guideline for solid phase aPL assays. Cut-off values and corresponding 90% confidence intervals (CI) for each antibody were established and outliers were handled according to the Clinical and Laboratory Standards Institute (CLSI) guideline for reference intervals. Samples from 377 consecutive patients, referred to our thrombophilia center with evidence of thrombosis or pregnancy morbidity were included for aPL testing. Results The in-house 99th (97.5th) percentile cut-off values were 11 (8.7), 12 (6.9) 8.5 (5.0) AU/mL for aβ2GPI IgG, IgM and IgA, and 21 (13) GPL-U/mL and 41 (25) MPL-U/mL for aCL IgG and IgM, respectively. The prevalence of positive results (%) defined by these cut-off values in patients with evidence of thrombosis or pregnancy morbidity was 9.5 (12.2), 1.6 (2.9), and 7.0 (9.9), and 0.8 (3.8) for aβ2GPI IgG, IgM, and aCL IgG and IgM respectively. The use of in-house 99th percentile cut-off values compared to the manufacturer suggested cut-off values resulted in 1 and 39 fewer samples for aβ2GPI and aCL to be classified as positive for aPL, respectively. Conclusions We present Phadia/EliA cut-off values with 90% CI for aPL determined systematically according to the ISTH and CLSI guidelines. These values are different from values previously determined, suggesting variation of aPLs in different populations. Our findings indicate the need for each laboratory to determine/validate assay specific cut-off values for aPL.
Classifying post-stroke fatigue: Optimal cut-off on the Fatigue Assessment Scale.

PubMed

Cumming, Toby B; Mead, Gillian

2017-12-01

Post-stroke fatigue is common and has debilitating effects on independence and quality of life. The Fatigue Assessment Scale (FAS) is a valid screening tool for fatigue after stroke, but there is no established cut-off. We sought to identify the optimal cut-off for classifying post-stroke fatigue on the FAS. In retrospective analysis of two independent datasets (the '2015' and '2007' studies), we evaluated the predictive validity of FAS score against a case definition of fatigue (the criterion standard). Area under the curve (AUC) and sensitivity and specificity at the optimal cut-off were established in the larger 2015 dataset (n=126), and then independently validated in the 2007 dataset (n=52). In the 2015 dataset, AUC was 0.78 (95% CI 0.70-0.86), with the optimal ≥24 cut-off giving a sensitivity of 0.82 and specificity of 0.66. The 2007 dataset had an AUC of 0.83 (95% CI 0.71-0.94), and applying the ≥24 cut-off gave a sensitivity of 0.84 and specificity of 0.67. Post-hoc analysis of the 2015 dataset revealed that using only the 3 most predictive FAS items together ('FAS-3') also yielded good validity: AUC 0.81 (95% CI 0.73-0.89), with sensitivity of 0.83 and specificity of 0.75 at the optimal ≥8 cut-off. We propose ≥24 as a cut-off for classifying post-stroke fatigue on the FAS. While further validation work is needed, this is a positive step towards a coherent approach to reporting fatigue prevalence using the FAS. Copyright © 2017 Elsevier Inc. All rights reserved.
Extended international (IOTF) body mass index cut-offs for thinness, overweight and obesity.

PubMed

Cole, T J; Lobstein, T

2012-08-01

The international (International Obesity Task Force; IOTF) body mass index (BMI) cut-offs are widely used to assess the prevalence of child overweight, obesity and thinness. Based on data from six countries fitted by the LMS method, they link BMI values at 18 years (16, 17, 18.5, 25 and 30 kg m(-2)) to child centiles, which are averaged across the countries. Unlike other BMI references, e.g. the World Health Organization (WHO) standard, these cut-offs cannot be expressed as centiles (e.g. 85th). To address this, we averaged the previously unpublished L, M and S curves for the six countries, and used them to derive new cut-offs defined in terms of the centiles at 18 years corresponding to each BMI value. These new cut-offs were compared with the originals, and with the WHO standard and reference, by measuring their prevalence rates based on US and Chinese data. The new cut-offs were virtually identical to the originals, giving prevalence rates differing by < 0.2% on average. The discrepancies were smaller for overweight and obesity than for thinness. The international and WHO prevalences were systematically different before/after age 5. Defining the international cut-offs in terms of the underlying LMS curves has several benefits. New cut-offs are easy to derive (e.g. BMI 35 for morbid obesity), and they can be expressed as BMI centiles (e.g. boys obesity = 98.9th centile), allowing them to be compared with other BMI references. For WHO, median BMI is relatively low in early life and high at older ages, probably due to its method of construction. © 2012 The Authors. Pediatric Obesity © 2012 International Association for the Study of Obesity.
Body mass index, waist circumference and waist-to-hip ratio cut-off points for categorisation of obesity among Omani Arabs.

PubMed

Al-Lawati, Jawad A; Jousilahti, Pekka

2008-01-01

There are no data on optimal cut-off points to classify obesity among Omani Arabs. The existing cut-off points were obtained from studies of European populations. To determine gender-specific optimal cut-off points for body mass index (BMI), waist circumference (WC) and waist-to-hip ratio (WHR) associated with elevated prevalent cardiovascular disease (CVD) risk among Omani Arabs. A community-based cross-sectional study. The survey was conducted in the city of Nizwa in Oman in 2001. The study contained a probabilistic random sample of 1421 adults aged > or =20 years. Prevalent CVD risk was defined as the presence of at least two of the following three risk factors: hyperglycaemia, hypertension and dyslipidaemia. Logistic regression and receiver-operating characteristic (ROC) curve analyses were used to determine optimal cut-off points for BMI, WC and WHR in relation to the area under the curve (AUC), sensitivity and specificity. Over 87% of Omanis had at least one CVD risk factor (38% had hyperglycaemia, 19% hypertension and 34.5% had high total cholesterol). All three indices including BMI (AUC = 0.766), WC (AUC = 0.772) and WHR (AUC = 0.767) predicted prevalent CVD risk factors equally well. The optimal cut-off points for men and women respectively were 23.2 and 26.8 kg m-2 for BMI, 80.0 and 84.5 cm for WC, and 0.91 and 0.91 for WHR. To identify Omani subjects of Arab ethnicity at high risk of CVD, cut-off points lower than currently recommended for BMI, WC and WHR are needed for men while higher cut-off points are suggested for women.
The Hb E (HBB: c.79G>A), Mean Corpuscular Volume, Mean Corpuscular Hemoglobin Cutoff Points in Double Heterozygous Hb E/- -SEA α-Thalassemia-1 Carriers are Dependent on Hemoglobin Levels.

PubMed

Leckngam, Prapapun; Limweeraprajak, Ektong; Kiewkarnkha, Tiemjan; Tatu, Thanusak

2017-01-01

Identifying double heterozygosities in Hb E (HBB: c.79 G>A)/- - SEA (Southeast Asian) (α-thalassemia-1) (α-thal-1) in patients first diagnosed as carrying Hb E is important in thalassemia control. Low Hb E, mean corpuscular volume (MCV) and mean corpuscular hemoglobin (Hb) (MCH) levels have been observed in this double heterozygosity. However, the cutoff points of these parameters have never been systematically established. Here, we analyzed Hb E and red blood cell (RBC) parameters in 372 Hb E patients grouped by Hb levels, by the status of - - SEA and -α 3.7 (α-thal-2; rightward) deletions, to establish the cutoff points. Then, the established cutoff points were evaluated in 184 Hb E patients. It was found that the cutoff points of Hb E, MCV, MCH were significantly dependent on the Hb levels. In the group having Hb levels <10.0 g/dL, the cutoff points of Hb E, MCV and MCH were 21.2%, 64.9 fL and 21.0 pg, respectively, and were 25.6%, 72.8 fL and 23.9 pg, respectively, in the group having Hb levels 10.0-11.9 g/dL. Finally, in the group having Hb levels ≥12.0 g/dL, the cutoff points of Hb E, MCV and MCH were 27.1%, 76.7 fL and 25.3 pg, respectively. Thus, to screen for the double heterozygous Hb E/- - SEA anomaly in patients initially diagnosed as carrying Hb E, the Hb levels must be taken into account in choosing the suitable cutoff points of these three parameters.
The cut-off values of anthropometric variables for predicting mild cognitive impairment in Malaysian older adults: a large population based cross-sectional study.

PubMed

Won, Huiloo; Abdul, Manaf Zahara; Mat Ludin, Arimi Fitri; Omar, Mohd Azahadi; Razali, Rosdinom; Shahar, Suzana

2017-01-01

Older adults are at risk of mild cognitive impairment (MCI), and simple anthropometric measurements can be used to screen for this condition. Thus, the aim of this study was to explore the cut-off values of body mass index (BMI) and waist circumference (WC) for predicting the risk of MCI in older Malaysian adults. A total of 2,240 Malaysian older adults aged ≥60 years were recruited using multistage random sampling in a population based cross-sectional study. Receiver operating characteristic (ROC) curve was used to determine the cut-off values of BMI and WC with optimum sensitivity and specificity for the detection of MCI. Age, gender, years of education, smoking habit, alcohol consumption, depression, and medical conditions were used as confounding factors in this analysis. A BMI cut-off value of 26 kg/m 2 (area under the receiver operating characteristic curve [AUC] 0.725; sensitivity 90.5%; specificity 38.8%) was appropriate in identifying the risk of getting MCI in both men and women. The optimum WC cut-offs for likelihood of MCI were 90 cm (AUC 0.745; sensitivity 78.0%; specificity 59.8%) for men and 82 cm (AUC 0.714; sensitivity 84.3%; specificity 49.7%) for women. The optimum calf circumference (CC) cut-off values for identifying MCI were 29 cm (AUC 0.731; sensitivity 72.6%; specificity 61.1%) for men and 26 cm (AUC 0.598; sensitivity 79.1%; specificity 45.3%) for women. The cut-off values could be advocated and used as part of the screening of MCI among older Malaysian adults. There is a need to further determine the predictive values of these cut-off points on outcomes through longitudinal study design.
A sensitive assay for urinary cocaine metabolite benzoylecgonine shows more positive results and longer half-lives than those using traditional cut-offs.

PubMed

Nickley, Joyce; Pesce, Amadeo J; Krock, Kevin

2017-08-01

Cocaine is a common drug of abuse. To detect its use, a screening detection concentration for the cocaine metabolite benzoylecgonine is commonly set at 150 ng/mL and its confirmatory cut-off is set at 100 ng/mL. Studies have suggested that these cut-offs may be set too high, allowing some patients with this substance abuse problem to be missed or improperly monitored. With the advent of liquid chromatography-tandem mass spectrometry (LC-MS/MS) technology it is possible to reliably detect and quantify lower concentrations of its metabolite benzoylecgonine as part of a larger drug panel. One purpose of the study was to establish if there was a significant increase in detection of cocaine use with a ten-fold more sensitive cut-off. A very sensitive dilute and shoot assay for benzoylecgonine was developed with a lower limit of quantitation of 5 ng/mL. Validation of the 5 ng/mL cut-off was achieved by plotting all the positive cocaine observations as a frequency distribution on a logarithmic scale. The number of positive results with measurable concentrations below the typical industry 100 ng/mL cut-off level but above the high sensitivity 5 ng/mL cut-off level was observed to be 51.9% of the observed positives. The lower cut-off also allowed a re-evaluation of the window of detection after cessation of use. It was observed to be between 17 and 22 days. © 2016 Precision Diagnostics, LLC. Drug Testing and Analysis published by John Wiley & Sons, Ltd. © 2016 Precision Diagnostics, LLC. Drug Testing and Analysis published by John Wiley & Sons, Ltd.
Sensitivity and specificity of the Beck Depression Inventory in cardiologic inpatients: how useful is the conventional cut-off score?

PubMed

Forkmann, Thomas; Vehren, Thomas; Boecker, Maren; Norra, Christine; Wirtz, Markus; Gauggel, Siegfried

2009-10-01

The Beck Depression Inventory (BDI) is widely used for depression screening in various patient populations. However, there are still insufficient data about its sensitivity and specificity in nonpsychiatric patients. Furthermore, some research suggests that somatic BDI items heighten its sum score artificially in physically ill patients. The aim of the present study was to validate the conventional BDI cut-off score by examination of its sensitivity and specificity in a mixed sample of cardiac inpatients and compare it to a modified "cognitive-emotional" BDI (BDI(c/e)) after exclusion of somatic items. A total of 126 cardiologic inpatients were assessed. Receiver operating characteristic curves (ROC) were calculated for total BDI (BDI(t)) and BDI(c/e). Screening performance of cut-off scores was evaluated using the Youden Index (Y). With the application of the conventional BDI cut-off score, ROC analysis revealed a moderate overall screening performance with Y=52.6 and an area under the curve (AUC) of 0.83. In contrast, Y improved to 57.5 at a cut-off score of >9, but screening performance was still not optimal. BDI(c/e) showed also a moderate screening performance (AUC=.82); Y was maximized at a cut-off score of >8 (Y=0.53.5). Again, no cut-off score provided optimal screening performance. The BDI cannot be recommended as a formal screening instrument in cardiac inpatients since no cut-off score for either BDI(t) or BDI(c/e) combined both sufficiently high sensitivity and specificity. However, the shorter BDI(c/e) could be used as alternative to BDI(t) which may be confounded in physically ill patients. Generally, researchers should consider using alternative screening instruments (e.g., the Hospital Anxiety and Depression Scale) instead.
Prediction of esophageal varices and variceal hemorrhage in patients with acute upper gastrointestinal bleeding.

PubMed

Rockey, Don C; Elliott, Alan; Lyles, Thomas

2016-03-01

In patients with upper gastrointestinal bleeding (UGIB), identifying those with esophageal variceal hemorrhage prior to endoscopy would be clinically useful. This retrospective study of a large cohort of patients with UGIB used logistic regression analyses to evaluate the platelet count, aspartate aminotransferase (AST) to platelet ratio index (APRI), AST to alanine aminotransferase (ALT) ratio (AAR) and Lok index (all non-invasive blood markers) as predictors of variceal bleeding in (1) all patients with UGIB and (2) patients with cirrhosis and UGIB. 2233 patients admitted for UGIB were identified; 1034 patients had cirrhosis (46%) and of these, 555 patients (54%) had acute UGIB due to esophageal varices. In all patients with UGIB, the platelet count (cut-off 122,000/mm(3)), APRI (cut-off 5.1), AAR (cut-off 2.8) and Lok index (cut-off 0.9) had area under the curve (AUC)s of 0.80 0.82, 0.64, and 0.80, respectively, for predicting the presence of varices prior to endoscopy. To predict varices as the culprit of bleeding, the platelet count (cut-off 69,000), APRI (cut-off 2.6), AAR (cut-off 2.5) and Lok Index (0.90) had AUCs of 0.76, 0.77, 0.57 and 0.73, respectively. Finally, in patients with cirrhosis and UGIB, logistic regression was unable to identify optimal cut-off values useful for predicting varices as the culprit bleeding lesion for any of the non-invasive markers studied. For all patients with UGIB, non-invasive markers appear to differentiate patients with varices from those without varices and to identify those with a variceal culprit lesion. However, these markers could not distinguish between a variceal culprit and other lesions in patients with cirrhosis. Copyright © 2016 American Federation for Medical Research.
Identification of hazardous drinking with the Young Adult Alcohol Consequences Questionnaire: Relative operating characteristics as a function of gender.

PubMed

Read, Jennifer P; Haas, Amie L; Radomski, Sharon; Wickham, Robert E; Borish, Sarah E

2016-10-01

Heavy and problematic drinking is common on college campuses and is associated with myriad hazardous outcomes. The Young Adult Alcohol Consequences Questionnaire (YAACQ; Read et al., 2006) was developed to provide comprehensive and expedient assessment of negative consequences of young adult drinking and has been used in a number of research and clinical settings. To date, no empirically derived cutoffs for the YAACQ have been available for use in the identification of those drinkers at greatest risk. This was the objective of the present study. In a large (N = 1,311) and demographically heterogeneous multisite sample, we identified cutoff scores for the YAACQ, and the contrasted detection of hazardous drinking using these cutoffs with those recommended for the Alcohol Use Disorders Identification Test (AUDIT). We also examined whether cutoffs differed by gender. Results of receiver operating characteristic (ROC) analysis yielded cutoffs that delineate 3 levels (or zones) of hazardous drinking risk: low, moderate, and high. A cutoff of 8 differentiated those at low risk from those at moderate risk or greater, and a cutoff of 16 differentiated between moderate and high risk. These zones corresponded to other indices of risky drinking, including heavy episodic "binge" drinking, more frequent alcohol consumption, and engagement in alcohol risk behaviors. Scores differentiating low to moderate risk differed for men (8) and women (10), whereas the cutoff for high risk was the same (16) across the sexes. Findings suggest that the YAACQ can be used to reliably assess level of drinking risk among college students. Furthermore, these cut scores may be used to refer to interventions varying in intensity level, based on level of indicated alcohol risk. (PsycINFO Database Record (c) 2016 APA, all rights reserved).
Efficient Maintenance and Update of Nonbonded Lists in Macromolecular Simulations.

PubMed

Chowdhury, Rezaul; Beglov, Dmitri; Moghadasi, Mohammad; Paschalidis, Ioannis Ch; Vakili, Pirooz; Vajda, Sandor; Bajaj, Chandrajit; Kozakov, Dima

2014-10-14

Molecular mechanics and dynamics simulations use distance based cutoff approximations for faster computation of pairwise van der Waals and electrostatic energy terms. These approximations traditionally use a precalculated and periodically updated list of interacting atom pairs, known as the "nonbonded neighborhood lists" or nblists, in order to reduce the overhead of finding atom pairs that are within distance cutoff. The size of nblists grows linearly with the number of atoms in the system and superlinearly with the distance cutoff, and as a result, they require significant amount of memory for large molecular systems. The high space usage leads to poor cache performance, which slows computation for large distance cutoffs. Also, the high cost of updates means that one cannot afford to keep the data structure always synchronized with the configuration of the molecules when efficiency is at stake. We propose a dynamic octree data structure for implicit maintenance of nblists using space linear in the number of atoms but independent of the distance cutoff. The list can be updated very efficiently as the coordinates of atoms change during the simulation. Unlike explicit nblists, a single octree works for all distance cutoffs. In addition, octree is a cache-friendly data structure, and hence, it is less prone to cache miss slowdowns on modern memory hierarchies than nblists. Octrees use almost 2 orders of magnitude less memory, which is crucial for simulation of large systems, and while they are comparable in performance to nblists when the distance cutoff is small, they outperform nblists for larger systems and large cutoffs. Our tests show that octree implementation is approximately 1.5 times faster in practical use case scenarios as compared to nblists.
The Source of Planetary Period Oscillations in Saturn's Magnetosphere

NASA Astrophysics Data System (ADS)

Khurana, Krishan K.; Mitchell, Jonathan L.; Mueller, Ingo C. F.

2017-04-01

In this presentation, we resolve a three-decades old mystery of how Saturn is able to modulate its kilometric wave radiation and many field and plasma parameters at the planetary rotation period even though its magnetic field is extremely axisymmetric. Such waves emanating from the auroral regions of planets lacking solid surfaces have been used as clocks to measure the lengths of their days, because asymmetric internal magnetic fields spin-modulate wave amplitudes. A review by Carbary and Mitchell (2013, Periodicities in Saturn's magnetosphere, Reviews of Geophysics, 51, 1-30) on the topic summarized findings from over 200 research articles, on what the phenomena is, how it is manifested in a host of magnetospheric and auroral parameters; examined several proposed models and pointed out their shortcomings. The topic has now been explored in several topical international workshops, but the problem has remained unsolved so far. By quantitatively modeling the amplitudes and phases of these oscillations in the magnetic field observed by the Cassini spacecraft, we have now uncovered the generation mechanism responsible for these oscillations. We show that the observed oscillations are the manifestations of two global convectional conveyor belts excited in Saturn's upper atmosphere by auroral heating below its northern and southern auroral belts. We demonstrate that a feedback process develops in Saturn system such that the magnetosphere expends energy to drive convection in Saturn's upper stratosphere but gains back an amplified share in the form of angular momentum that it uses to enforce corotation in the magnetosphere and power its aurorae and radio waves. In essence, we have uncovered a new mechanism (convection assisted loss of angular momentum in an atmosphere) by which gaseous planets lose their angular momentum to their magnetospheres and outflowing plasma at rates far above previous predictions. We next show how the m = 1 convection system in the upper atmosphere generates the observed plasma and magnetic field periodicities. This breakthrough in our understanding of an important planetary physics problem has immediate and extensive applications in fields as diverse as theoretical fluid dynamics, planetary angular momentum loss, maintenance of corotation in planetary magnetospheres, astrophysical magneto-braking and future telescopic observations of planets and exoplanets.
Eigenvalue equation and core-mode cutoff of weakly guiding tapered fiber as three layer optical waveguide and used as biochemical sensor.

PubMed

Linslal, C L; Mohan, P M S; Halder, A; Gangopadhyay, T K

2012-06-01

The core-mode cutoff plays a major role in evanescent field absorption based sensors. A method has been proposed to calculate the core-mode cutoff by solving the eigenvalue equations of a weakly guiding three layer optical waveguide graphically. The variation of normalized waveguide parameter (V) is also calculated with different wavelengths at core-mode cutoff. At the first step, theoretical analysis of tapered fiber parameters has been performed for core-mode cutoff. The taper angle of an adiabatic tapered fiber is also analyzed using the length-scale criterion. Secondly, single-mode tapered fiber has been developed to make a precision sensor element suitable for chemical detection. Finally, the sensor element has been used to detect absorption peak of ethylenediamine. Results are presented in which an absorption peak at 1540 nm is observed.
Tables of asymptotic directions, cutoff rigidities, and reentrant albedo calculations for Palestine, Dallas, and Midland, Texas. Special repts

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

Shea, M.A.; Smart, D.F.

1974-03-26

Using the trajectory-tracing technique, the asymptotic directions and cut-off rigidities for Palestine, Dallas, amd Midland,Texas were calculated as a function of various zenith and azimuth angles. Continuation of the trajectory-tracing process below the Stormer cutoff allows an evaluation of the reentrant albedo; the invariant latitude of the guiding center of the trajectory at the albedo origin is seen to be the same as the invariant latitude of the guiding center of the particle trajectory at the specified zenith and azimuth angle of the detection point. Tables of asymptotic directions, cutoff rigidities, and the location of the reentrant albedo for eachmore » of these locations are given. Summaries of cutoff rigidity calculations as a function of zenith and azimuth directions for some miscellaneous locations are also included. (GRA)« less

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