Science.gov

Sample records for magnitud del problema

  1. Sobre las soluciones acotadas del problema instantáneo de dos cuerpos

    NASA Astrophysics Data System (ADS)

    Altavista, C.

    La demostración se basa en el hecho de que las integrales del problema de los N-cuerpos admiten componentes en el campo complejo según las raíces n-ésimas de la unidad. Definida la matriz unitaria correspondiente, la fórmula de Cayley permite transformar la matriz unitaria en una matriz hermitiana. Utilizando como parámetros los cosenos direccionales de un sistema de coordenadas orbitales referidos a un sistema de referencia fijo, puede construirse, utilizando el operador hermitiano antes definido, una forma cuadrática cuyas raíces mínima y máxima definen las cotas respectivas de los movimientos de los mencionados cosenos direccionales.

  2. Estructura orbital en el Problema Restringido Rectilíneo Isósceles

    NASA Astrophysics Data System (ADS)

    Orellana, R. B.

    Para definir problemas en Mecánica Celeste se utilizan diferentes parámetros. El conocimiento de la dinámica del problema para valores particulares de estos parámetros nos permite entender el comportamiento en casos más generales. El Problema Restringido Rectilíneo Isósceles puede ser considerado como el caso límite del Problema de Sitnikov cuando la excentricidad tiende a uno o como el Problema Isósceles cuando la masa central tiende a cero. Se ha compactificado el espacio de fases y analizado la dinámica en el límite. Esto ha permitido separar el espacio de fases en diferentes regiones dependiendo de las clases de órbitas.

  3. Automaticity of Conceptual Magnitude

    PubMed Central

    Gliksman, Yarden; Itamar, Shai; Leibovich, Tali; Melman, Yonatan; Henik, Avishai

    2016-01-01

    What is bigger, an elephant or a mouse? This question can be answered without seeing the two animals, since these objects elicit conceptual magnitude. How is an object’s conceptual magnitude processed? It was suggested that conceptual magnitude is automatically processed; namely, irrelevant conceptual magnitude can affect performance when comparing physical magnitudes. The current study further examined this question and aimed to expand the understanding of automaticity of conceptual magnitude. Two different objects were presented and participants were asked to decide which object was larger on the screen (physical magnitude) or in the real world (conceptual magnitude), in separate blocks. By creating congruent (the conceptually larger object was physically larger) and incongruent (the conceptually larger object was physically smaller) pairs of stimuli it was possible to examine the automatic processing of each magnitude. A significant congruity effect was found for both magnitudes. Furthermore, quartile analysis revealed that the congruity was affected similarly by processing time for both magnitudes. These results suggest that the processing of conceptual and physical magnitudes is automatic to the same extent. The results support recent theories suggested that different types of magnitude processing and representation share the same core system. PMID:26879153

  4. Are Earthquake Magnitudes Clustered?

    SciTech Connect

    Davidsen, Joern; Green, Adam

    2011-03-11

    The question of earthquake predictability is a long-standing and important challenge. Recent results [Phys. Rev. Lett. 98, 098501 (2007); ibid.100, 038501 (2008)] have suggested that earthquake magnitudes are clustered, thus indicating that they are not independent in contrast to what is typically assumed. Here, we present evidence that the observed magnitude correlations are to a large extent, if not entirely, an artifact due to the incompleteness of earthquake catalogs and the well-known modified Omori law. The latter leads to variations in the frequency-magnitude distribution if the distribution is constrained to those earthquakes that are close in space and time to the directly following event.

  5. Misconceptions about astronomical magnitudes

    NASA Astrophysics Data System (ADS)

    Schulman, Eric; Cox, Caroline V.

    1997-10-01

    The present system of astronomical magnitudes was created as an inverse scale by Claudius Ptolemy in about 140 A.D. and was defined to be logarithmic in 1856 by Norman Pogson, who believed that human eyes respond logarithmically to the intensity of light. Although scientists have known for some time that the response is instead a power law, astronomers continue to use the Pogson magnitude scale. The peculiarities of this system make it easy for students to develop numerous misconceptions about how and why to use magnitudes. We present a useful exercise in the use of magnitudes to derive a cosmologically interesting quantity (the mass-to-light ratio for spiral galaxies), with potential pitfalls pointed out and explained.

  6. Telescopic limiting magnitudes

    NASA Technical Reports Server (NTRS)

    Schaefer, Bradley E.

    1990-01-01

    The prediction of the magnitude of the faintest star visible through a telescope by a visual observer is a difficult problem in physiology. Many prediction formulas have been advanced over the years, but most do not even consider the magnification used. Here, the prediction algorithm problem is attacked with two complimentary approaches: (1) First, a theoretical algorithm was developed based on physiological data for the sensitivity of the eye. This algorithm also accounts for the transmission of the atmosphere and the telescope, the brightness of the sky, the color of the star, the age of the observer, the aperture, and the magnification. (2) Second, 314 observed values for the limiting magnitude were collected as a test of the formula. It is found that the formula does accurately predict the average observed limiting magnitudes under all conditions.

  7. Should Astronomy Abolish Magnitudes?

    NASA Astrophysics Data System (ADS)

    Brecher, K.

    2001-12-01

    Astronomy is riddled with a number of anachronistic and counterintuitive practices. Among these are: plotting increasing stellar temperature from right to left in the H-R diagram; giving the distances to remote astronomical objects in parsecs; and reporting the brightness of astronomical objects in magnitudes. Historical accident and observational technique, respectively, are the bases for the first two practices, and they will undoubtedly persist in the future. However, the use of magnitudes is especially egregious when essentially linear optical detectors like CCDs are used for measuring brightness, which are then reported in a logarithmic (base 2.512 deg!) scale. The use of magnitudes has its origin in three historical artifacts: Ptolemy's method of reporting the brightness of stars in the "Almagest"; the 19th century need for a photographic photometry scale; and the 19th century studies by psychophysicists E. H. Weber and G. T. Fechner on the response of the human eye to light. The latter work sought to uncover the relationship between the subjective response of the human eye and brain to the objective brightness of external optical stimuli. The resulting Fechner-Weber law states that this response is logarithmic: that is, that the eye essentially takes the logarithm of the incoming optical signal. However, after more than a century of perceptual studies, most intensively by S. S. Stevens, it is now well established that this relation is not logarithmic. For naked eye detection of stars from the first to sixth magnitudes, it can be reasonably well fit by a power law with index of about 0.3. Therefore, the modern experimental studies undermine the physiological basis for the use of magnitudes in astronomy. Should the historical origins of magnitudes alone be reason enough for their continued use? Probably not, since astronomical magnitudes are based on outdated studies of human perception; make little sense in an era of linear optical detection; and provide a

  8. Regression problems for magnitudes

    NASA Astrophysics Data System (ADS)

    Castellaro, S.; Mulargia, F.; Kagan, Y. Y.

    2006-06-01

    Least-squares linear regression is so popular that it is sometimes applied without checking whether its basic requirements are satisfied. In particular, in studying earthquake phenomena, the conditions (a) that the uncertainty on the independent variable is at least one order of magnitude smaller than the one on the dependent variable, (b) that both data and uncertainties are normally distributed and (c) that residuals are constant are at times disregarded. This may easily lead to wrong results. As an alternative to least squares, when the ratio between errors on the independent and the dependent variable can be estimated, orthogonal regression can be applied. We test the performance of orthogonal regression in its general form against Gaussian and non-Gaussian data and error distributions and compare it with standard least-square regression. General orthogonal regression is found to be superior or equal to the standard least squares in all the cases investigated and its use is recommended. We also compare the performance of orthogonal regression versus standard regression when, as often happens in the literature, the ratio between errors on the independent and the dependent variables cannot be estimated and is arbitrarily set to 1. We apply these results to magnitude scale conversion, which is a common problem in seismology, with important implications in seismic hazard evaluation, and analyse it through specific tests. Our analysis concludes that the commonly used standard regression may induce systematic errors in magnitude conversion as high as 0.3-0.4, and, even more importantly, this can introduce apparent catalogue incompleteness, as well as a heavy bias in estimates of the slope of the frequency-magnitude distributions. All this can be avoided by using the general orthogonal regression in magnitude conversions.

  9. El problema de estabilidad de los sistemas Hamiltonianos multidimensionales

    NASA Astrophysics Data System (ADS)

    Cincotta, P. M.

    Se revisarán los aspectos básicos del problema de estabilidad de sistemans Hamiltonianos N-dimensionales, haciendo especial énfasis en los posibles mecanismos que dan lugar a la aparición de ``caos": overlap de resonancias, difusión de Arnol'd y otros procesos difusivos alternativos. Se mencionarán los aspectos aún no resueltos sobre la estabilidad de los sistemas con N > 2. Finalmente, se discutirá cuáles de estos mecanismos podrían tener alguna relevancia en la dinámica de sistemas estelares y planetarios.

  10. Landslide seismic magnitude

    NASA Astrophysics Data System (ADS)

    Lin, C. H.; Jan, J. C.; Pu, H. C.; Tu, Y.; Chen, C. C.; Wu, Y. M.

    2015-11-01

    Landslides have become one of the most deadly natural disasters on earth, not only due to a significant increase in extreme climate change caused by global warming, but also rapid economic development in topographic relief areas. How to detect landslides using a real-time system has become an important question for reducing possible landslide impacts on human society. However, traditional detection of landslides, either through direct surveys in the field or remote sensing images obtained via aircraft or satellites, is highly time consuming. Here we analyze very long period seismic signals (20-50 s) generated by large landslides such as Typhoon Morakot, which passed though Taiwan in August 2009. In addition to successfully locating 109 large landslides, we define landslide seismic magnitude based on an empirical formula: Lm = log ⁡ (A) + 0.55 log ⁡ (Δ) + 2.44, where A is the maximum displacement (μm) recorded at one seismic station and Δ is its distance (km) from the landslide. We conclude that both the location and seismic magnitude of large landslides can be rapidly estimated from broadband seismic networks for both academic and applied purposes, similar to earthquake monitoring. We suggest a real-time algorithm be set up for routine monitoring of landslides in places where they pose a frequent threat.

  11. Magnitude correlations in global seismicity

    SciTech Connect

    Sarlis, N. V.

    2011-08-15

    By employing natural time analysis, we analyze the worldwide seismicity and study the existence of correlations between earthquake magnitudes. We find that global seismicity exhibits nontrivial magnitude correlations for earthquake magnitudes greater than M{sub w}6.5.

  12. Comparison of TV magnitudes and visual magnitudes of meteors

    NASA Astrophysics Data System (ADS)

    Shigeno, Yoshihiko; Toda, Masayuki

    2008-08-01

    The generally accepted belief is that a meteor, with a large amount of infrared rays, can be captured brighter than it actually is by infrared-sensitive image intensifiers (I.I.) or CCD. We conducted observations of meteors using three methodologies: 1) I.I. with an attached filter that has the same spectral response as the human eye at night vision, 2) I.I. without the filter and 3) visually to determine meteor magnitudes. A total of 31 members of the astronomical club at Meiji University observed 50 Perseid meteors, 19 Geminid meteors as well as 44 sporadic meteors and the results were tabulated. The results helped us understand that on average I.I. can record meteors as brighter than visual observation by the magnitude equivalent of 0.5 for Perseids, 1.0 for Geminids and 0.5 for sporadic meteors. For I.I. with a filter that has the same spectral response the human eye at night vision, it turned out that we could obtain almost the same magnitude with observation by the human eye. We learned that a bright meteor with negative magnitude can be observed by I.I. brighter than the human eye. From several examples, we found I.I. could record a meteor with about -1 visual magnitude as brighter by about three magnitudes. We could probably do so because a bright meteor with negative magnitude may contain more infrared rays and the brightness could be amplified.

  13. Integrated Circuit Stellar Magnitude Simulator

    ERIC Educational Resources Information Center

    Blackburn, James A.

    1978-01-01

    Describes an electronic circuit which can be used to demonstrate the stellar magnitude scale. Six rectangular light-emitting diodes with independently adjustable duty cycles represent stars of magnitudes 1 through 6. Experimentally verifies the logarithmic response of the eye. (Author/GA)

  14. Amplitude-dependent station magnitude

    NASA Astrophysics Data System (ADS)

    Radzyner, Yael; Ben Horin, Yochai; Steinberg, David M.

    2016-04-01

    Magnitude, a concept first presented by Gutenberg and Richter, adjusts measurements of ground motion for epicentral distance and source depth. Following this principle, the IDC defines the j'th station body wave magnitude for event i as mb(stai,j) = log 10(Aj,i/Tj,i) + V C(Δj,i,hi) , where VC is the Veith-Clawson (VC) correction to compensate for the epicentral distance of the station and the depth of the source. The network magnitude is calculated as the average of station magnitudes. The IDC magnitude estimation is used for event characterization and discrimination and it should be as accurate as possible. Ideally, the network magnitude should be close in value to the station magnitudes. In reality, it is observed that the residuals range between -1 and 1 mu or ±25% of a given mb(neti) value. We show that the residual, mb(neti) -mb(staj,i), depends linearly on log 10(Aj,i/Tj,i), and we correct for this dependence using the following procedure: Calculate a "jackknifed" network magnitude, mbj,n(neti), i.e. an average over all participating stations except station n. Using all measurements at station n, calculate the parameters an, bn of the linear fit of the residual mbj,n(neti) - mb(stan,i to log 10(An,i/Tn,i). For each event i at station n calculate the new station magnitude mbnew(stan,i) = (an + 1)log(An,i/Tn,i) + V C(Δn,i,hi) + bn Calculate the new network magnitude: mbnew(neti) = 1N- ∑ n=1nmbnew(stan,i) The procedure was used on more than two million station-event pairs. Correcting for the station-specific dependence on log amplitude reduces the residuals by roughly a third. We have calculated the spread of the distributions, and compared the original values and those for the corrected magnitudes. The spread is the ratio between the variance of the network magnitudes, and the variance of the residual. Calculations show an increase in the ratio of the variance, meaning that the correction process presented in this document did not lead to loss of variance

  15. Bidirectional Modulation of Numerical Magnitude.

    PubMed

    Arshad, Qadeer; Nigmatullina, Yuliya; Nigmatullin, Ramil; Asavarut, Paladd; Goga, Usman; Khan, Sarah; Sander, Kaija; Siddiqui, Shuaib; Roberts, R E; Cohen Kadosh, Roi; Bronstein, Adolfo M; Malhotra, Paresh A

    2016-05-01

    Numerical cognition is critical for modern life; however, the precise neural mechanisms underpinning numerical magnitude allocation in humans remain obscure. Based upon previous reports demonstrating the close behavioral and neuro-anatomical relationship between number allocation and spatial attention, we hypothesized that these systems would be subject to similar control mechanisms, namely dynamic interhemispheric competition. We employed a physiological paradigm, combining visual and vestibular stimulation, to induce interhemispheric conflict and subsequent unihemispheric inhibition, as confirmed by transcranial direct current stimulation (tDCS). This allowed us to demonstrate the first systematic bidirectional modulation of numerical magnitude toward either higher or lower numbers, independently of either eye movements or spatial attention mediated biases. We incorporated both our findings and those from the most widely accepted theoretical framework for numerical cognition to present a novel unifying computational model that describes how numerical magnitude allocation is subject to dynamic interhemispheric competition. That is, numerical allocation is continually updated in a contextual manner based upon relative magnitude, with the right hemisphere responsible for smaller magnitudes and the left hemisphere for larger magnitudes.

  16. Bidirectional Modulation of Numerical Magnitude.

    PubMed

    Arshad, Qadeer; Nigmatullina, Yuliya; Nigmatullin, Ramil; Asavarut, Paladd; Goga, Usman; Khan, Sarah; Sander, Kaija; Siddiqui, Shuaib; Roberts, R E; Cohen Kadosh, Roi; Bronstein, Adolfo M; Malhotra, Paresh A

    2016-05-01

    Numerical cognition is critical for modern life; however, the precise neural mechanisms underpinning numerical magnitude allocation in humans remain obscure. Based upon previous reports demonstrating the close behavioral and neuro-anatomical relationship between number allocation and spatial attention, we hypothesized that these systems would be subject to similar control mechanisms, namely dynamic interhemispheric competition. We employed a physiological paradigm, combining visual and vestibular stimulation, to induce interhemispheric conflict and subsequent unihemispheric inhibition, as confirmed by transcranial direct current stimulation (tDCS). This allowed us to demonstrate the first systematic bidirectional modulation of numerical magnitude toward either higher or lower numbers, independently of either eye movements or spatial attention mediated biases. We incorporated both our findings and those from the most widely accepted theoretical framework for numerical cognition to present a novel unifying computational model that describes how numerical magnitude allocation is subject to dynamic interhemispheric competition. That is, numerical allocation is continually updated in a contextual manner based upon relative magnitude, with the right hemisphere responsible for smaller magnitudes and the left hemisphere for larger magnitudes. PMID:26879093

  17. Bidirectional Modulation of Numerical Magnitude

    PubMed Central

    Arshad, Qadeer; Nigmatullina, Yuliya; Nigmatullin, Ramil; Asavarut, Paladd; Goga, Usman; Khan, Sarah; Sander, Kaija; Siddiqui, Shuaib; Roberts, R. E.; Cohen Kadosh, Roi; Bronstein, Adolfo M.; Malhotra, Paresh A.

    2016-01-01

    Numerical cognition is critical for modern life; however, the precise neural mechanisms underpinning numerical magnitude allocation in humans remain obscure. Based upon previous reports demonstrating the close behavioral and neuro-anatomical relationship between number allocation and spatial attention, we hypothesized that these systems would be subject to similar control mechanisms, namely dynamic interhemispheric competition. We employed a physiological paradigm, combining visual and vestibular stimulation, to induce interhemispheric conflict and subsequent unihemispheric inhibition, as confirmed by transcranial direct current stimulation (tDCS). This allowed us to demonstrate the first systematic bidirectional modulation of numerical magnitude toward either higher or lower numbers, independently of either eye movements or spatial attention mediated biases. We incorporated both our findings and those from the most widely accepted theoretical framework for numerical cognition to present a novel unifying computational model that describes how numerical magnitude allocation is subject to dynamic interhemispheric competition. That is, numerical allocation is continually updated in a contextual manner based upon relative magnitude, with the right hemisphere responsible for smaller magnitudes and the left hemisphere for larger magnitudes. PMID:26879093

  18. Calibration de la magnitude absolue.

    NASA Astrophysics Data System (ADS)

    Gómez, A. E.; Mennessier, M. O.

    Les parallaxes mesurées par Hipparcos permettront d'obtenir des magnitudes absolues individuelles meilleures que ±0m4 pour les étoiles placées dans un volume de rayon inférieur à 150 pc environ autour du soleil. Les algorithmes développés dans le cadre de l'exploitation des données d'Hipparcos, basés sur la méthode de maximum de vraisemblance, permettent non seulement de faire une estimation de la magnitude absolue moyenne d'un groupe physiquement homogène d'étoiles, de son comportement cinématique et de sa distribution spatiale mais aussi d'estimer une magnitude absolue individuelle pour chaque étoile de l'échantillon considéré.

  19. The Testability of Maximum Magnitude

    NASA Astrophysics Data System (ADS)

    Clements, R.; Schorlemmer, D.; Gonzalez, A.; Zoeller, G.; Schneider, M.

    2012-12-01

    Recent disasters caused by earthquakes of unexpectedly large magnitude (such as Tohoku) illustrate the need for reliable assessments of the seismic hazard. Estimates of the maximum possible magnitude M at a given fault or in a particular zone are essential parameters in probabilistic seismic hazard assessment (PSHA), but their accuracy remains untested. In this study, we discuss the testability of long-term and short-term M estimates and the limitations that arise from testing such rare events. Of considerable importance is whether or not those limitations imply a lack of testability of a useful maximum magnitude estimate, and whether this should have any influence on current PSHA methodology. We use a simple extreme value theory approach to derive a probability distribution for the expected maximum magnitude in a future time interval, and we perform a sensitivity analysis on this distribution to determine if there is a reasonable avenue available for testing M estimates as they are commonly reported today: devoid of an appropriate probability distribution of their own and estimated only for infinite time (or relatively large untestable periods). Our results imply that any attempt at testing such estimates is futile, and that the distribution is highly sensitive to M estimates only under certain optimal conditions that are rarely observed in practice. In the future we suggest that PSHA modelers be brutally honest about the uncertainty of M estimates, or must find a way to decrease its influence on the estimated hazard.

  20. Understanding Magnitudes to Understand Fractions

    ERIC Educational Resources Information Center

    Gabriel, Florence

    2016-01-01

    Fractions are known to be difficult to learn and difficult to teach, yet they are vital for students to have access to further mathematical concepts. This article uses evidence to support teachers employing teaching methods that focus on the conceptual understanding of the magnitude of fractions.

  1. Solar Variability Magnitudes and Timescales

    NASA Astrophysics Data System (ADS)

    Kopp, Greg

    2015-08-01

    The Sun’s net radiative output varies on timescales of minutes to many millennia. The former are directly observed as part of the on-going 37-year long total solar irradiance climate data record, while the latter are inferred from solar proxy and stellar evolution models. Since the Sun provides nearly all the energy driving the Earth’s climate system, changes in the sunlight reaching our planet can have - and have had - significant impacts on life and civilizations.Total solar irradiance has been measured from space since 1978 by a series of overlapping instruments. These have shown changes in the spatially- and spectrally-integrated radiant energy at the top of the Earth’s atmosphere from timescales as short as minutes to as long as a solar cycle. The Sun’s ~0.01% variations over a few minutes are caused by the superposition of convection and oscillations, and even occasionally by a large flare. Over days to weeks, changing surface activity affects solar brightness at the ~0.1% level. The 11-year solar cycle has comparable irradiance variations with peaks near solar maxima.Secular variations are harder to discern, being limited by instrument stability and the relatively short duration of the space-borne record. Proxy models of the Sun based on cosmogenic isotope records and inferred from Earth climate signatures indicate solar brightness changes over decades to millennia, although the magnitude of these variations depends on many assumptions. Stellar evolution affects yet longer timescales and is responsible for the greatest solar variabilities.In this talk I will summarize the Sun’s variability magnitudes over different temporal ranges, showing examples relevant for climate studies as well as detections of exo-solar planets transiting Sun-like stars.

  2. [Differences in magnitude of nutritional status in Chilean school children according to CDC and WHO 2005-2008 reference].

    PubMed

    Vásquez, Fabián; Cerda Rioseco, Ricardo; Andrade, Margarita; Morales, Gladys; Gálvez, Patricia; Orellana, Yasna; Leyton, Bárbara

    2013-01-01

    Introducción: Es necesario realizar nuevas discusiones respecto a la magnitud de los problemas nutricionales diagnosticados, al usar CDC u OMS, frente a la existencia de nuevas definiciones biológicas o estadísticas de obesidad. Objetivo: Comparar la evolución de la prevalencia de estado nutricional en escolares de primero básico, desde el 2013 2005 al 2008, según CDC y OMS. Métodos: Cohorte retrospectiva, de 140.265 escolares de ambos sexos de primero básico, evaluados entre 2005- 2008, cuyos datos antropométricos (peso y talla), se obtuvieron del sistema anual de registro del estado nutricional escolar. Para clasificar el estado nutricional, se utilizaron los patrones CDC y OMS. Resultados: Los promedios de IMC fueron levemente diferentes y menores en la niñas que en los niños, en 2005 y 2006. Durante el 2007 y 2008 el promedio de IMC en las niñas alcanzó la cifra observada en los varones. Hubo mayor prevalencia de bajo peso según OMS (p=0,03), con una tendencia a la disminución en los 2013s posteriores. La prevalencia de normalidad fue mayor según el criterio CDC, con una reducción entre el 2005 y 2007 y un incremento 2008 (p<0,001). Hubo una menor prevalencia de sobrepeso según el criterio CDC (p<0,001), con aumento entre el 2005 y 2007, tanto CDC como OMS. La prevalencia de obesidad fue menor según el criterio OMS, no encontrándose diferencia estadísticamente significativa al comparar con el patrón CDC. Conclusiones: Al comparar ambos patrones, CDC tiende a sobreestimar la normalidad y subestimar el sobrepeso, mientras que en obesidad no se encontraron diferencias significativas.

  3. Magnitude correlations and dynamical scaling for seismicity

    SciTech Connect

    Godano, Cataldo; Lippiello, Eugenio; De Arcangelis, Lucilla

    2007-12-06

    We analyze the experimental seismic catalog of Southern California and we show the existence of correlations between earthquake magnitudes. We propose a dynamical scaling hypothesis relating time and magnitude as the physical mechanism responsible of the observed magnitude correlations. We show that experimental distributions in size and time naturally originate solely from this scaling hypothesis. Furthermore we generate a synthetic catalog reproducing the organization in time and magnitude of experimental data.

  4. Magnitude and sign correlations in heartbeat fluctuations

    NASA Technical Reports Server (NTRS)

    Ashkenazy, Y.; Ivanov, P. C.; Havlin, S.; Peng, C. K.; Goldberger, A. L.; Stanley, H. E.

    2001-01-01

    We propose an approach for analyzing signals with long-range correlations by decomposing the signal increment series into magnitude and sign series and analyzing their scaling properties. We show that signals with identical long-range correlations can exhibit different time organization for the magnitude and sign. We find that the magnitude series relates to the nonlinear properties of the original time series, while the sign series relates to the linear properties. We apply our approach to the heartbeat interval series and find that the magnitude series is long-range correlated, while the sign series is anticorrelated and that both magnitude and sign series may have clinical applications.

  5. The discovery and comparison of symbolic magnitudes.

    PubMed

    Chen, Dawn; Lu, Hongjing; Holyoak, Keith J

    2014-06-01

    Humans and other primates are able to make relative magnitude comparisons, both with perceptual stimuli and with symbolic inputs that convey magnitude information. Although numerous models of magnitude comparison have been proposed, the basic question of how symbolic magnitudes (e.g., size or intelligence of animals) are derived and represented in memory has received little attention. We argue that symbolic magnitudes often will not correspond directly to elementary features of individual concepts. Rather, magnitudes may be formed in working memory based on computations over more basic features stored in long-term memory. We present a model of how magnitudes can be acquired and compared based on BARTlet, a representationally simpler version of Bayesian Analogy with Relational Transformations (BART; Lu, Chen, & Holyoak, 2012). BARTlet operates on distributions of magnitude variables created by applying dimension-specific weights (learned with the aid of empirical priors derived from pre-categorical comparisons) to more primitive features of objects. The resulting magnitude distributions, formed and maintained in working memory, are sensitive to contextual influences such as the range of stimuli and polarity of the question. By incorporating psychological reference points that control the precision of magnitudes in working memory and applying the tools of signal detection theory, BARTlet is able to account for a wide range of empirical phenomena involving magnitude comparisons, including the symbolic distance effect and the semantic congruity effect. We discuss the role of reference points in cognitive and social decision-making, and implications for the evolution of relational representations.

  6. Magnitude systems in old star catalogues

    NASA Astrophysics Data System (ADS)

    Fujiwara, Tomoko; Yamaoka, Hitoshi

    2005-06-01

    The current system of stellar magnitudes originally introduced by Hipparchus was strictly defined by Norman Pogson in 1856. He based his system on Ptolemy's star catalogue, the Almagest, recorded in about AD137, and defined the magnitude-intensity relationship on a logarithmic scale. Stellar magnitudes observed with the naked eye recorded in seven old star catalogues were analyzed in order to examine the visual magnitude systems. Although psychophysicists have proposed that human visual sensitivity follows a power-law scale, it is shown here that the degree of agreement is far better for a logarithmic scale than for a power-law scale. It is also found that light ratios in each star catalogue are nearly equal to 2.512, if the brightest (1st magnitude) and the faintest (6th magnitude and dimmer) stars are excluded from the study. This means that the visual magnitudes in the old star catalogues agree fully with Pogson's logarithmic scale.

  7. Absolute magnitudes of trans-neptunian objects

    NASA Astrophysics Data System (ADS)

    Duffard, R.; Alvarez-candal, A.; Pinilla-Alonso, N.; Ortiz, J. L.; Morales, N.; Santos-Sanz, P.; Thirouin, A.

    2015-10-01

    Accurate measurements of diameters of trans- Neptunian objects are extremely complicated to obtain. Radiomatric techniques applied to thermal measurements can provide good results, but precise absolute magnitudes are needed to constrain diameters and albedos. Our objective is to measure accurate absolute magnitudes for a sample of trans- Neptunian objects, many of which have been observed, and modelled, by the "TNOs are cool" team, one of Herschel Space Observatory key projects grantes with ~ 400 hours of observing time. We observed 56 objects in filters V and R, if possible. These data, along with data available in the literature, was used to obtain phase curves and to measure absolute magnitudes by assuming a linear trend of the phase curves and considering magnitude variability due to rotational light-curve. In total we obtained 234 new magnitudes for the 56 objects, 6 of them with no reported previous measurements. Including the data from the literature we report a total of 109 absolute magnitudes.

  8. Reward Magnitude Effects on Temporal Discrimination

    ERIC Educational Resources Information Center

    Galtress, Tiffany; Kirkpatrick, Kimberly

    2010-01-01

    Changes in reward magnitude or value have been reported to produce effects on timing behavior, which have been attributed to changes in the speed of an internal pacemaker in some instances and to attentional factors in other cases. The present experiments therefore aimed to clarify the effects of reward magnitude on timing processes. In Experiment…

  9. Representations of the Magnitudes of Fractions

    ERIC Educational Resources Information Center

    Schneider, Michael; Siegler, Robert S.

    2010-01-01

    We tested whether adults can use integrated, analog, magnitude representations to compare the values of fractions. The only previous study on this question concluded that even college students cannot form such representations and instead compare fraction magnitudes by representing numerators and denominators as separate whole numbers. However,…

  10. Local magnitudes of small contained explosions.

    SciTech Connect

    Chael, Eric Paul

    2009-12-01

    The relationship between explosive yield and seismic magnitude has been extensively studied for underground nuclear tests larger than about 1 kt. For monitoring smaller tests over local ranges (within 200 km), we need to know whether the available formulas can be extrapolated to much lower yields. Here, we review published information on amplitude decay with distance, and on the seismic magnitudes of industrial blasts and refraction explosions in the western U. S. Next we measure the magnitudes of some similar shots in the northeast. We find that local magnitudes ML of small, contained explosions are reasonably consistent with the magnitude-yield formulas developed for nuclear tests. These results are useful for estimating the detection performance of proposed local seismic networks.

  11. Measuring radon source magnitude in residential buildings

    SciTech Connect

    Nazaroff, W.W.; Boegel, M.L.; Nero, A.V.

    1981-08-01

    A description is given of procedures used in residences for rapid grab-sample and time-dependent measurements of the air-exchange rate and radon concentration. The radon source magnitude is calculated from the results of simultaneous measurements of these parameters. Grab-sample measurements in three survey groups comprising 101 US houses showed the radon source magnitude to vary approximately log-normally with a geometric mean of 0.37 and a range of 0.01 to 6.0 pCi 1/sup -1/ h/sup -1/. Successive measurements in six houses in the northeastern United States showed considerable variability in source magnitude within a given house. In two of these houses the source magnitude showed a strong correlation with the air-exchange rate, suggesting that soil gas influx can be an important transport process for indoor radon.

  12. Determination of the Meteor Limiting Magnitude

    NASA Technical Reports Server (NTRS)

    Kingery, A.; Blaauw, R.; Cooke, W. J.

    2016-01-01

    The limiting meteor magnitude of a meteor camera system will depend on the camera hardware and software, sky conditions, and the location of the meteor radiant. Some of these factors are constants for a given meteor camera system, but many change between meteor shower or sporadic source and on both long and short timescales. Since the limiting meteor magnitude ultimately gets used to calculate the limiting meteor mass for a given data set, it is important to have an understanding of these factors and to monitor how they change throughout the night, as a 0.5 magnitude uncertainty in limiting magnitude translates to a uncertainty in limiting mass by a factor of two.

  13. Magnitude and frequency of floods in Alabama

    USGS Publications Warehouse

    Olin, D.A.

    1985-01-01

    Methods are presented to estimate flood magnitude for selected recurrence intervals for urban and rural streams with drainage areas from 1 to 22,000 square miles. Seven hydrologic areas were delineated and regression equations were developed for six areas. Hydrologic data could not be regionalized for the seventh area. Drainage area was the only independent variable used in the equations for five hydrologic areas. Drainage area and a storage factor were used in the equations for the other area. One hydrologic area, located in the central part of the State, has flood runoffs two to four times greater than the other areas. It is recommended that the rural equations be used for estimates of flood magnitudes for both urban and rural streams in the hydrologic area. Rivers with drainage areas greater than 1,500 square miles could not be regionalized. Estimating methods for these rivers are shown graphically. Maximum flood magnitudes versus drainage area also are presented. (USGS)

  14. Delta Scorpii unusual brightening to first magnitude

    NASA Astrophysics Data System (ADS)

    Sigismondi, Costantino

    2016-01-01

    The Be star delta Scorpii with a range of variability between 2.35 and 1.65 in visible light is having an unusual brightening to magnitude mV=0.8, as measured on 31 Jan 2016 at 3:56 UT and 5:36 UT from Lanciano, Italy.

  15. K Giant Magnitude Calibration from Parallaxes

    NASA Astrophysics Data System (ADS)

    Gould, A.; Flynn, C.

    1992-02-01

    We test the Janes (1975, 1979) calibration of K giant magnitudes from DDO colours against a sample of 40 local parallax stars. These stars are taken from the sample analyzed by Egret, Keenan, and Heck (1982), but are further selected for Janes magnitude (0m.80 &le MJV ≤ 2m.2), colour (1.0 ≤ B-V ≤ 1.5), and metallicity (-0.5 ≤ [Fe/H] ≤ 0.0). We find these stars to be on average very slightly brighter (δMJV = -0m.07±0m.10) than the Janes values. Our result is in agreement with a recent redetermination of the Janes magnitude offset by Flynn and Mermilliod (1991) (δMJV = 0m.07 ± 0m.09) on the basis of open-cluster stars. However, we disagree with the calibration of Egret, Keenan, and Heck by a full magnitude. Half of this difference is due to changes in the parallax catalog values and to slightly different selection criteria. We cannot account for the remaining half.

  16. Is there a magnitude effect in tipping?

    PubMed

    Green, Leonard; Myerson, Joel; Schneider, Rachel

    2003-06-01

    The present study examined nearly 1,000 tips recorded for two taxicabs, two hair salons, and two restaurants. In each of the six cases, amount of tip increased linearly as a function of the amount of the bill. Contrary to standard microeconomic theory, there was a magnitude effect in that as the amount of the bill increased, the percent tip tended to decrease. The present results extend the findings of Chapman and Winquist (1998), obtained using hypothetical scenarios, to real-world tipping behavior. Chapman and Winquist argued that a magnitude effect in tipping reflects the shape of the utility function for money. We suggest, however, that the magnitude effect may be the mathematical consequence of replotting the fundamental relationship between tip and bill amounts in terms of percent tip, given that the observed linear relation between tip and bill amounts has a positive intercept. We suggest further that the positive intercept arises because a tip represents a judgment as to what constitutes a fair or equitable wage, and part of what constitutes a fair wage is independent of the amount of the bill, reflecting compensation for simply being there when needed. The present account implies that different explanations may be needed for magnitude effects observed in different domains.

  17. Color and magnitude dependence of galaxy clustering

    NASA Astrophysics Data System (ADS)

    Müller, Volker

    2016-10-01

    A quantitative study of the clustering properties of galaxies in the cosmic web as a function of absolute magnitude and colour is presented using the SDSS Data Release 7 galaxy redshift survey. We compare our results with mock galaxy samples obtained with four different semi-analytical models of galaxy formation imposed on the merger trees of the Millenium simulation.

  18. Fast Regional Magnitude Determination at INGV

    NASA Astrophysics Data System (ADS)

    Michelini, A.; Lomax, A.; Bono, A.; Amato, A.

    2006-12-01

    The recent, very large earthquakes in the Indian Ocean and Indonesia have shown the importance of rapid magnitude determination for tsunami warning. In the Mediterranean region, destructive tsunamis have occurred repeatedly in the past; however, because of the proximity of the tsunami sources to populated coasts, very rapid analysis is necessary for effective warning. Reliable estimates of the earthquake location and size should be available within tens of seconds after the first arriving P-waves are recorded at local and regional distances. Currently in Europe there is no centralized agency such as the PTWC for the Pacific Ocean dedicated to issue tsunami warnings, though, recent initiatives, such as the NEAMTWS (North-East Atlantic and Mediterranean Tsunami Warning System), aim toward the establishment of such an agency. Thus established seismic monitoring centers, such as INGV, Rome, are currently relied upon for rapid earthquake analysis and information dissemination. In this study, we describe the recent, experimental implementation at the INGV seismic center of a procedure for rapid magnitude determination at regional distances based on the Mwp methodology (Tsuboi et al., 1995), which exploits information in the P-wave train. For our Mwp determinations, we have implemented an automatic procedure that windows the relevant part of the seismograms and picks the amplitudes of the first two largest peaks, providing within seconds after each P arrival an estimate of earthquake size. Manual revision is completed using interactive software that presents an analysis with the seismograms, amplitude picks and magnitude estimates. We have compared our Mwp magnitudes for recent earthquakes within the Mediterranean region with Mw determined through the Harvard CMT procedure. For the majority of the events, the Mwp and Mw magnitudes agree closely, indicating that the rapid Mwp estimates forms a useful tool for effective tsunami warning on a regional scale.

  19. Subitizing, Magnitude Representation, and Magnitude Retrieval in Deaf and Hearing Adults

    ERIC Educational Resources Information Center

    Bull, Rebecca; Blatto-Vallee, Gary; Fabich, Megan

    2006-01-01

    This study examines basic number processing (subitizing, automaticity, and magnitude representation) as the possible underpinning of mathematical difficulties often evidenced in deaf adults. Hearing and deaf participants completed tasks to assess the automaticity with which magnitude information was activated and retrieved from long-term memory…

  20. Asteroid absolute magnitudes and slope parameters

    NASA Technical Reports Server (NTRS)

    Tedesco, Edward F.

    1991-01-01

    A new listing of absolute magnitudes (H) and slope parameters (G) has been created and published in the Minor Planet Circulars; this same listing will appear in the 1992 Ephemerides of Minor Planets. Unlike previous listings, the values of the current list were derived from fits of data at the V band. All observations were reduced in the same fashion using, where appropriate, a single basis default value of 0.15 for the slope parameter. Distances and phase angles were computed for each observation. The data for 113 asteroids was of sufficiently high quality to permit derivation of their H and G. These improved absolute magnitudes and slope parameters will be used to deduce the most reliable bias-corrected asteroid size-frequency distribution yet made.

  1. Absolute-magnitude distributions of supernovae

    SciTech Connect

    Richardson, Dean; Wright, John; Jenkins III, Robert L.; Maddox, Larry

    2014-05-01

    The absolute-magnitude distributions of seven supernova (SN) types are presented. The data used here were primarily taken from the Asiago Supernova Catalogue, but were supplemented with additional data. We accounted for both foreground and host-galaxy extinction. A bootstrap method is used to correct the samples for Malmquist bias. Separately, we generate volume-limited samples, restricted to events within 100 Mpc. We find that the superluminous events (M{sub B} < –21) make up only about 0.1% of all SNe in the bias-corrected sample. The subluminous events (M{sub B} > –15) make up about 3%. The normal Ia distribution was the brightest with a mean absolute blue magnitude of –19.25. The IIP distribution was the dimmest at –16.75.

  2. Absolute magnitudes and kinematics of barium stars.

    NASA Astrophysics Data System (ADS)

    Gomez, A. E.; Luri, X.; Grenier, S.; Prevot, L.; Mennessier, M. O.; Figueras, F.; Torra, J.

    1997-03-01

    The absolute magnitude of barium stars has been obtained from kinematical data using a new algorithm based on the maximum-likelihood principle. The method allows to separate a sample into groups characterized by different mean absolute magnitudes, kinematics and z-scale heights. It also takes into account, simultaneously, the censorship in the sample and the errors on the observables. The method has been applied to a sample of 318 barium stars. Four groups have been detected. Three of them show a kinematical behaviour corresponding to disk population stars. The fourth group contains stars with halo kinematics. The luminosities of the disk population groups spread a large range. The intrinsically brightest one (M_v_=-1.5mag, σ_M_=0.5mag) seems to be an inhomogeneous group containing barium binaries as well as AGB single stars. The most numerous group (about 150 stars) has a mean absolute magnitude corresponding to stars in the red giant branch (M_v_=0.9mag, σ_M_=0.8mag). The third group contains barium dwarfs, the obtained mean absolute magnitude is characteristic of stars on the main sequence or on the subgiant branch (M_v_=3.3mag, σ_M_=0.5mag). The obtained mean luminosities as well as the kinematical results are compatible with an evolutionary link between barium dwarfs and classical barium giants. The highly luminous group is not linked with these last two groups. More high-resolution spectroscopic data will be necessary in order to better discriminate between barium and non-barium stars.

  3. Magnitude and frequency of floods in Washington

    USGS Publications Warehouse

    Cummans, J.E.; Collings, Michael R.; Nasser, Edmund George

    1975-01-01

    Relations are provided to estimate the magnitude and frequency of floods on Washington streams. Annual-peak-flow data from stream gaging stations on unregulated streams having 1 years or more of record were used to determine a log-Pearson Type III frequency curve for each station. Flood magnitudes having recurrence intervals of 2, 5, i0, 25, 50, and 10years were then related to physical and climatic indices of the drainage basins by multiple-regression analysis using the Biomedical Computer Program BMDO2R. These regression relations are useful for estimating flood magnitudes of the specified recurrence intervals at ungaged or short-record sites. Separate sets of regression equations were defined for western and eastern parts of the State, and the State was further subdivided into 12 regions in which the annual floods exhibit similar flood characteristics. Peak flows are related most significantly in western Washington to drainage-area size and mean annual precipitation. In eastern Washington-they are related most significantly to drainage-area size, mean annual precipitation, and percentage of forest cover. Standard errors of estimate of the estimating relations range from 25 to 129 percent, and the smallest errors are generally associated with the more humid regions.

  4. Local magnitude scale for earthquakes in Turkey

    NASA Astrophysics Data System (ADS)

    Kılıç, T.; Ottemöller, L.; Havskov, J.; Yanık, K.; Kılıçarslan, Ö.; Alver, F.; Özyazıcıoğlu, M.

    2016-06-01

    Based on the earthquake event data accumulated by the Turkish National Seismic Network between 2007 and 2013, the local magnitude (Richter, Ml) scale is calibrated for Turkey and the close neighborhood. A total of 137 earthquakes (Mw > 3.5) are used for the Ml inversion for the whole country. Three Ml scales, whole country, East, and West Turkey, are developed, and the scales also include the station correction terms. Since the scales for the two parts of the country are very similar, it is concluded that a single Ml scale is suitable for the whole country. Available data indicate the new scale to suffer from saturation beyond magnitude 6.5. For this data set, the horizontal amplitudes are on average larger than vertical amplitudes by a factor of 1.8. The recommendation made is to measure Ml amplitudes on the vertical channels and then add the logarithm scale factor to have a measure of maximum amplitude on the horizontal. The new Ml is compared to Mw from EMSC, and there is almost a 1:1 relationship, indicating that the new scale gives reliable magnitudes for Turkey.

  5. Maximum magnitude earthquakes induced by fluid injection

    NASA Astrophysics Data System (ADS)

    McGarr, A.

    2014-02-01

    Analysis of numerous case histories of earthquake sequences induced by fluid injection at depth reveals that the maximum magnitude appears to be limited according to the total volume of fluid injected. Similarly, the maximum seismic moment seems to have an upper bound proportional to the total volume of injected fluid. Activities involving fluid injection include (1) hydraulic fracturing of shale formations or coal seams to extract gas and oil, (2) disposal of wastewater from these gas and oil activities by injection into deep aquifers, and (3) the development of enhanced geothermal systems by injecting water into hot, low-permeability rock. Of these three operations, wastewater disposal is observed to be associated with the largest earthquakes, with maximum magnitudes sometimes exceeding 5. To estimate the maximum earthquake that could be induced by a given fluid injection project, the rock mass is assumed to be fully saturated, brittle, to respond to injection with a sequence of earthquakes localized to the region weakened by the pore pressure increase of the injection operation and to have a Gutenberg-Richter magnitude distribution with a b value of 1. If these assumptions correctly describe the circumstances of the largest earthquake, then the maximum seismic moment is limited to the volume of injected liquid times the modulus of rigidity. Observations from the available case histories of earthquakes induced by fluid injection are consistent with this bound on seismic moment. In view of the uncertainties in this analysis, however, this should not be regarded as an absolute physical limit.

  6. Evolution and magnitudes of candidate Planet Nine

    NASA Astrophysics Data System (ADS)

    Linder, Esther F.; Mordasini, Christoph

    2016-05-01

    Context. The recently renewed interest in a possible additional major body in the outer solar system prompted us to study the thermodynamic evolution of such an object. We assumed that it is a smaller version of Uranus and Neptune. Aims: We modeled the temporal evolution of the radius, temperature, intrinsic luminosity, and the blackbody spectrum of distant ice giant planets. The aim is also to provide estimates of the magnitudes in different bands to assess whether the object might be detectable. Methods: Simulations of the cooling and contraction were conducted for ice giants with masses of 5, 10, 20, and 50 M⊕ that are located at 280, 700, and 1120 AU from the Sun. The core composition, the fraction of H/He, the efficiency of energy transport, and the initial luminosity were varied. The atmospheric opacity was set to 1, 50, and 100 times solar metallicity. Results: We find for a nominal 10 M⊕ planet at 700 AU at the current age of the solar system an effective temperature of 47 K, much higher than the equilibrium temperature of about 10 K, a radius of 3.7 R⊕, and an intrinsic luminosity of 0.006 L♃. It has estimated apparent magnitudes of Johnson V, R, I, L, N, Q of 21.7, 21.4, 21.0, 20.1, 19.9, and 10.7, and WISE W1-W4 magnitudes of 20.1, 20.1, 18.6, and 10.2. The Q and W4 band and other observations longward of about 13 μm pick up the intrinsic flux. Conclusions: If candidate Planet 9 has a significant H/He layer and an efficient energy transport in the interior, then its luminosity is dominated by the intrinsic contribution, making it a self-luminous planet. At a likely position on its orbit near aphelion, we estimate for a mass of 5, 10, 20, and 50 M⊕ a V magnitude from the reflected light of 24.3, 23.7, 23.3, and 22.6 and a Q magnitude from the intrinsic radiation of 14.6, 11.7, 9.2, and 5.8. The latter would probably have been detected by past surveys.

  7. Orientation and Magnitude of Mars' Magnetic Field

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This image shows the orientation and magnitude of the magnetic field measured by the MGS magnetometer as it sped over the surface of Mars during an early aerobraking pass (Day of the year, 264; 'P6' periapsis pass). At each point along the spacecraft trajectory we've drawn vectors in the direction of the magnetic field measured at that instant; the length of the line is scaled to show the relative magnitude of the field. Imagine traveling along with the MGS spacecraft, holding a string with a magnetized needle on one end: this essentially a compass with a needle that is free to spin in all directions. As you pass over the surface the needle would swing rapidly, first pointing towards the planet and then rotating quickly towards 'up' and back down again. All in a relatively short span of time, say a minute or two, during which time the spacecraft has traveled a couple of hundred miles. You've just passed over one of many 'magnetic anomalies' thus far detected near the surface of Mars. A second major anomaly appears a little later along the spacecraft track, about 1/4 the magnitude of the first - can you find it? The short scale length of the magnetic field signature locates the source near the surface of Mars, perhaps in the crust, a 10 to 75 kilometer thick outer shell of the planet (radius 3397 km).

    The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO. JPL is an operating division of California Institute of Technology (Caltech).

  8. Apparent magnitude of earthshine: a simple calculation

    NASA Astrophysics Data System (ADS)

    Agrawal, Dulli Chandra

    2016-05-01

    The Sun illuminates both the Moon and the Earth with practically the same luminous fluxes which are in turn reflected by them. The Moon provides a dim light to the Earth whereas the Earth illuminates the Moon with somewhat brighter light which can be seen from the Earth and is called earthshine. As the amount of light reflected from the Earth depends on part of the Earth and the cloud cover, the strength of earthshine varies throughout the year. The measure of the earthshine light is luminance, which is defined in photometry as the total luminous flux of light hitting or passing through a surface. The expression for the earthshine light in terms of the apparent magnitude has been derived for the first time and evaluated for two extreme cases; firstly, when the Sun’s rays are reflected by the water of the oceans and secondly when the reflector is either thick clouds or snow. The corresponding values are -1.30 and -3.69, respectively. The earthshine value -3.22 reported by Jackson lies within these apparent magnitudes. This paper will motivate the students and teachers of physics to look for the illuminated Moon by earthlight during the waning or waxing crescent phase of the Moon and to reproduce the expressions derived here by making use of the inverse-square law of radiation, Planck’s expression for the power in electromagnetic radiation, photopic spectral luminous efficiency function and expression for the apparent magnitude of a body in terms of luminous fluxes.

  9. Precise Relative Earthquake Magnitudes from Cross Correlation

    DOE PAGESBeta

    Cleveland, K. Michael; Ammon, Charles J.

    2015-04-21

    We present a method to estimate precise relative magnitudes using cross correlation of seismic waveforms. Our method incorporates the intercorrelation of all events in a group of earthquakes, as opposed to individual event pairings relative to a reference event. This method works well when a reliable reference event does not exist. We illustrate the method using vertical strike-slip earthquakes located in the northeast Pacific and Panama fracture zone regions. Our results are generally consistent with the Global Centroid Moment Tensor catalog, which we use to establish a baseline for the relative event sizes.

  10. The intensities and magnitudes of volcanic eruptions

    USGS Publications Warehouse

    Sigurdsson, H.

    1991-01-01

    Ever since 1935, when C.F Richter devised the earthquake magnitude scale that bears his name, seismologists have been able to view energy release from earthquakes in a systematic and quantitative manner. The benefits have been obvious in terms of assessing seismic gaps and the spatial and temporal trends of earthquake energy release. A similar quantitative treatment of volcanic activity is of course equally desirable, both for gaining a further understanding of the physical principles of volcanic eruptions and for volcanic-hazard assessment. A systematic volcanologic data base would be of great value in evaluating such features as volcanic gaps, and regional and temporal trends in energy release.  

  11. Violence against women: global scope and magnitude.

    PubMed

    Watts, Charlotte; Zimmerman, Cathy

    2002-04-01

    An increasing amount of research is beginning to offer a global overview of the extent of violence against women. In this paper we discuss the magnitude of some of the most common and most severe forms of violence against women: intimate partner violence; sexual abuse by non-intimate partners; trafficking, forced prostitution, exploitation of labour, and debt bondage of women and girls; physical and sexual violence against prostitutes; sex selective abortion, female infanticide, and the deliberate neglect of girls; and rape in war. There are many potential perpetrators, including spouses and partners, parents, other family members, neighbours, and men in positions of power or influence. Most forms of violence are not unique incidents but are ongoing, and can even continue for decades. Because of the sensitivity of the subject, violence is almost universally under-reported. Nevertheless, the prevalence of such violence suggests that globally, millions of women are experiencing violence or living with its consequences. PMID:11955557

  12. Object file continuity predicts attentional blink magnitude.

    PubMed

    Kellie, Frances J; Shapiro, Kimron L

    2004-05-01

    When asked to identify targets embedded within a rapid consecutive stream of visual stimuli, observers are less able to identify the second target (T2) when it is presented within half a second of the first (T1); this deficit has been termed the attentional blink (AB). Rapid serial visual presentation methodology was used to investigate the relationship between the AB and object files (episodic representations implicated in object identification and perceptual constancy). An inverse linear relationship was found between the degree of object file continuity and AB magnitude. An important locus of object file continuity was the intervening stream items between T1 and T2. The results are discussed in terms of the heuristic of the object file to preserve limited attentional capacity.

  13. Definition, epidemiology and magnitude of alcoholic hepatitis

    PubMed Central

    Basra, Sarpreet; Anand, Bhupinderjit S

    2011-01-01

    Alcoholic liver disease (ALD) is a major cause of alcohol-related morbidity and mortality. Its presentation ranges from fatty liver to alcoholic hepatitis (AH), cirrhosis, and hepatocellular carcinoma. Although the amount and pattern of alcohol consumption is a well recognized predisposing factor for the development of serious liver pathology, environmental factors and the host’s genetic make-up may also play significant roles that have not yet been entirely explored. Continuing alcohol consumption is a major factor that influences the survival of patients with AH. The presence of cirrhosis at presentation or its development on follow up is a major factor determining the outcome in the long run. This chapter deals with the epidemiology and magnitude of ALD in general and AH in particular. PMID:21731902

  14. Evidence Accumulation in the Magnitude System

    PubMed Central

    Lambrechts, Anna; Walsh, Vincent; van Wassenhove, Virginie

    2013-01-01

    Perceptual interferences in the estimation of quantities (time, space and numbers) have been interpreted as evidence for a common magnitude system. However, if duration estimation has appears sensitive to spatial and numerical interferences, space and number estimation tend to be resilient to temporal manipulations. These observations question the relative contribution of each quantity in the elaboration of a representation in a common mental metric. Here, we elaborated a task in which perceptual evidence accumulated over time for all tested quantities (space, time and number) in order to match the natural requirement for building a duration percept. For this, we used a bisection task. Experimental trials consisted of dynamic dots of different sizes appearing progressively on the screen. Participants were asked to judge the duration, the cumulative surface or the number of dots in the display while the two non-target dimensions varied independently. In a prospective experiment, participants were informed before the trial which dimension was the target; in a retrospective experiment, participants had to attend to all dimensions and were informed only after a given trial which dimension was the target. Surprisingly, we found that duration was resilient to spatial and numerical interferences whereas space and number estimation were affected by time. Specifically, and counter-intuitively, results revealed that longer durations lead to smaller number and space estimates whether participants knew before (prospectively) or after (retrospectively) a given trial which quantity they had to estimate. Altogether, our results support a magnitude system in which perceptual evidence for time, space and numbers integrate following Bayesian cue-combination rules. PMID:24339998

  15. Controllo remoto del Dho's Observatory. III - La montatura, lo stazionamento, il problema della condensa

    NASA Astrophysics Data System (ADS)

    Dho, Mario

    2002-09-01

    We continue the study of an automated, self-built observatory. Some improvements the pier, the mounting, the instrument, and an anti-dew device will be the target of this third article. Besides, a very precise method to control and finely adjust the polar alignment of a telescope is discussed.

  16. Extended arrays for nonlinear susceptibility magnitude imaging

    PubMed Central

    Ficko, Bradley W.; Giacometti, Paolo; Diamond, Solomon G.

    2016-01-01

    This study implements nonlinear susceptibility magnitude imaging (SMI) with multifrequency intermodulation and phase encoding. An imaging grid was constructed of cylindrical wells of 3.5-mm diameter and 4.2-mm height on a hexagonal two-dimensional 61-voxel pattern with 5-mm spacing. Patterns of sample wells were filled with 40-μl volumes of Fe3O4 starch-coated magnetic nanoparticles (mNPs) with a hydrodynamic diameter of 100 nm and a concentration of 25 mg/ml. The imaging hardware was configured with three excitation coils and three detection coils in anticipation that a larger imaging system will have arrays of excitation and detection coils. Hexagonal and bar patterns of mNP were successfully imaged (R2 > 0.9) at several orientations. This SMI demonstration extends our prior work to feature a larger coil array, enlarged field-of-view, effective phase encoding scheme, reduced mNP sample size, and more complex imaging patterns to test the feasibility of extending the method beyond the pilot scale. The results presented in this study show that nonlinear SMI holds promise for further development into a practical imaging system for medical applications. PMID:26124044

  17. Estimating magnitude and duration of incident delays

    SciTech Connect

    Garib, A.; Radwan, A.E.; Al-Deek, H.

    1997-11-01

    Traffic congestion is a major operational problem on urban freeways. In the case of recurring congestion, travelers can plan their trips according to the expected occurrence and severity of recurring congestion. However, nonrecurring congestion cannot be managed without real-time prediction. Evaluating the efficiency of intelligent transportation systems (ITS) technologies in reducing incident effects requires developing models that can accurately predict incident duration along with the magnitude of nonrecurring congestion. This paper provides two statistical models for estimating incident delay and a model for predicting incident duration. The incident delay models showed that up to 85% of variation in incident delay can be explained by incident duration, number of lanes affected, number of vehicles involved, and traffic demand before the incident. The incident duration prediction model showed that 81% of variation in incident duration can be predicted by number of lanes affected, number of vehicles involved, truck involvement, time of day, police response time, and weather condition. These findings have implications for on-line applications within the context of advanced traveler information systems (ATIS).

  18. The magnitude distribution of dynamically triggered earthquakes

    NASA Astrophysics Data System (ADS)

    Hernandez, Stephen

    Large dynamic strains carried by seismic waves are known to trigger seismicity far from their source region. It is unknown, however, whether surface waves trigger only small earthquakes, or whether they can also trigger large, societally significant earthquakes. To address this question, we use a mixing model approach in which total seismicity is decomposed into 2 broad subclasses: "triggered" events initiated or advanced by far-field dynamic strains, and "untriggered" spontaneous events consisting of everything else. The b-value of a mixed data set, b MIX, is decomposed into a weighted sum of b-values of its constituent components, bT and bU. For populations of earthquakes subjected to dynamic strain, the fraction of earthquakes that are likely triggered, f T, is estimated via inter-event time ratios and used to invert for bT. The confidence bounds on b T are estimated by multiple inversions of bootstrap resamplings of bMIX and fT. For Californian seismicity, data are consistent with a single-parameter Gutenberg-Richter hypothesis governing the magnitudes of both triggered and untriggered earthquakes. Triggered earthquakes therefore seem just as likely to be societally significant as any other population of earthquakes.

  19. Extended arrays for nonlinear susceptibility magnitude imaging.

    PubMed

    Ficko, Bradley W; Giacometti, Paolo; Diamond, Solomon G

    2015-10-01

    This study implements nonlinear susceptibility magnitude imaging (SMI) with multifrequency intermodulation and phase encoding. An imaging grid was constructed of cylindrical wells of 3.5-mm diameter and 4.2-mm height on a hexagonal two-dimensional 61-voxel pattern with 5-mm spacing. Patterns of sample wells were filled with 40-μl volumes of Fe3O4 starch-coated magnetic nanoparticles (mNPs) with a hydrodynamic diameter of 100 nm and a concentration of 25 mg/ml. The imaging hardware was configured with three excitation coils and three detection coils in anticipation that a larger imaging system will have arrays of excitation and detection coils. Hexagonal and bar patterns of mNP were successfully imaged (R2>0.9) at several orientations. This SMI demonstration extends our prior work to feature a larger coil array, enlarged field-of-view, effective phase encoding scheme, reduced mNP sample size, and more complex imaging patterns to test the feasibility of extending the method beyond the pilot scale. The results presented in this study show that nonlinear SMI holds promise for further development into a practical imaging system for medical applications. PMID:26124044

  20. Analysis of earthquake body wave spectra for potency and magnitude values: implications for magnitude scaling relations

    NASA Astrophysics Data System (ADS)

    Ross, Zachary E.; Ben-Zion, Yehuda; White, Malcolm C.; Vernon, Frank L.

    2016-11-01

    We develop a simple methodology for reliable automated estimation of the low-frequency asymptote in seismic body wave spectra of small to moderate local earthquakes. The procedure corrects individual P- and S-wave spectra for propagation and site effects and estimates the seismic potency from a stacked spectrum. The method is applied to >11 000 earthquakes with local magnitudes 0 < ML < 4 that occurred in the Southern California plate-boundary region around the San Jacinto fault zone during 2013. Moment magnitude Mw values, derived from the spectra and the scaling relation of Hanks & Kanamori, follow a Gutenberg-Richter distribution with a larger b-value (1.22) from that associated with the ML values (0.93) for the same earthquakes. The completeness magnitude for the Mw values is 1.6 while for ML it is 1.0. The quantity (Mw - ML) linearly increases in the analysed magnitude range as ML decreases. An average earthquake with ML = 0 in the study area has an Mw of about 0.9. The developed methodology and results have important implications for earthquake source studies and statistical seismology.

  1. Nonlinear Susceptibility Magnitude Imaging of Magnetic Nanoparticles

    PubMed Central

    Ficko, Bradley W.; Giacometti, Paolo; Diamond, Solomon G.

    2014-01-01

    This study demonstrates a method for improving the resolution of susceptibility magnitude imaging (SMI) using spatial information that arises from the nonlinear magnetization characteristics of magnetic nanoparticles (mNPs). In this proof-of-concept study of nonlinear SMI, a pair of drive coils and several permanent magnets generate applied magnetic fields and a coil is used as a magnetic field sensor. Sinusoidal alternating current (AC) in the drive coils results in linear mNP magnetization responses at primary frequencies, and nonlinear responses at harmonic frequencies and intermodulation frequencies. The spatial information content of the nonlinear responses is evaluated by reconstructing tomographic images with sequentially increasing voxel counts using the combined linear and nonlinear data. Using the linear data alone it is not possible to accurately reconstruct more than 2 voxels with a pair of drive coils and a single sensor. However, nonlinear SMI is found to accurately reconstruct 12 voxels (R2 = 0.99, CNR = 84.9) using the same physical configuration. Several time-multiplexing methods are then explored to determine if additional spatial information can be obtained by varying the amplitude, phase and frequency of the applied magnetic fields from the two drive coils. Asynchronous phase modulation, amplitude modulation, intermodulation phase modulation, and frequency modulation all resulted in accurate reconstruction of 6 voxels (R2 > 0.9) indicating that time multiplexing is a valid approach to further increase the resolution of nonlinear SMI. The spatial information content of nonlinear mNP responses and the potential for resolution enhancement with time multiplexing demonstrate the concept and advantages of nonlinear SMI. PMID:25505816

  2. Nonlinear susceptibility magnitude imaging of magnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Ficko, Bradley W.; Giacometti, Paolo; Diamond, Solomon G.

    2015-03-01

    This study demonstrates a method for improving the resolution of susceptibility magnitude imaging (SMI) using spatial information that arises from the nonlinear magnetization characteristics of magnetic nanoparticles (mNPs). In this proof-of-concept study of nonlinear SMI, a pair of drive coils and several permanent magnets generate applied magnetic fields and a coil is used as a magnetic field sensor. Sinusoidal alternating current (AC) in the drive coils results in linear mNP magnetization responses at primary frequencies, and nonlinear responses at harmonic frequencies and intermodulation frequencies. The spatial information content of the nonlinear responses is evaluated by reconstructing tomographic images with sequentially increasing voxel counts using the combined linear and nonlinear data. Using the linear data alone it is not possible to accurately reconstruct more than 2 voxels with a pair of drive coils and a single sensor. However, nonlinear SMI is found to accurately reconstruct 12 voxels (R2=0.99, CNR=84.9) using the same physical configuration. Several time-multiplexing methods are then explored to determine if additional spatial information can be obtained by varying the amplitude, phase and frequency of the applied magnetic fields from the two drive coils. Asynchronous phase modulation, amplitude modulation, intermodulation phase modulation, and frequency modulation all resulted in accurate reconstruction of 6 voxels (R2>0.9) indicating that time multiplexing is a valid approach to further increase the resolution of nonlinear SMI. The spatial information content of nonlinear mNP responses and the potential for resolution enhancement with time multiplexing demonstrate the concept and advantages of nonlinear SMI.

  3. Magnitude and Frequency of Floods on Nontidal Streams in Delaware

    USGS Publications Warehouse

    Ries, Kernell G.; Dillow, Jonathan J.A.

    2006-01-01

    Reliable estimates of the magnitude and frequency of annual peak flows are required for the economical and safe design of transportation and water-conveyance structures. This report, done in cooperation with the Delaware Department of Transportation (DelDOT) and the Delaware Geological Survey (DGS), presents methods for estimating the magnitude and frequency of floods on nontidal streams in Delaware at locations where streamgaging stations monitor streamflow continuously and at ungaged sites. Methods are presented for estimating the magnitude of floods for return frequencies ranging from 2 through 500 years. These methods are applicable to watersheds exhibiting a full range of urban development conditions. The report also describes StreamStats, a web application that makes it easy to obtain flood-frequency estimates for user-selected locations on Delaware streams. Flood-frequency estimates for ungaged sites are obtained through a process known as regionalization, using statistical regression analysis, where information determined for a group of streamgaging stations within a region forms the basis for estimates for ungaged sites within the region. One hundred and sixteen streamgaging stations in and near Delaware with at least 10 years of non-regulated annual peak-flow data available were used in the regional analysis. Estimates for gaged sites are obtained by combining the station peak-flow statistics (mean, standard deviation, and skew) and peak-flow estimates with regional estimates of skew and flood-frequency magnitudes. Example flood-frequency estimate calculations using the methods presented in the report are given for: (1) ungaged sites, (2) gaged locations, (3) sites upstream or downstream from a gaged location, and (4) sites between gaged locations. Regional regression equations applicable to ungaged sites in the Piedmont and Coastal Plain Physiographic Provinces of Delaware are presented. The equations incorporate drainage area, forest cover, impervious

  4. Automatic computation of moment magnitudes for small earthquakes and the scaling of local to moment magnitude

    NASA Astrophysics Data System (ADS)

    Edwards, Benjamin; Allmann, Bettina; Fäh, Donat; Clinton, John

    2010-10-01

    Moment magnitudes (MW) are computed for small and moderate earthquakes using a spectral fitting method. 40 of the resulting values are compared with those from broadband moment tensor solutions and found to match with negligible offset and scatter for available MW values of between 2.8 and 5.0. Using the presented method, MW are computed for 679 earthquakes in Switzerland with a minimum ML = 1.3. A combined bootstrap and orthogonal L1 minimization is then used to produce a scaling relation between ML and MW. The scaling relation has a polynomial form and is shown to reduce the dependence of the predicted MW residual on magnitude relative to an existing linear scaling relation. The computation of MW using the presented spectral technique is fully automated at the Swiss Seismological Service, providing real-time solutions within 10 minutes of an event through a web-based XML database. The scaling between ML and MW is explored using synthetic data computed with a stochastic simulation method. It is shown that the scaling relation can be explained by the interaction of attenuation, the stress-drop and the Wood-Anderson filter. For instance, it is shown that the stress-drop controls the saturation of the ML scale, with low-stress drops (e.g. 0.1-1.0 MPa) leading to saturation at magnitudes as low as ML = 4.

  5. Influence of Time and Space Correlations on Earthquake Magnitude

    SciTech Connect

    Lippiello, E.; Arcangelis, L. de; Godano, C.

    2008-01-25

    A crucial point in the debate on the feasibility of earthquake predictions is the dependence of an earthquake magnitude from past seismicity. Indeed, while clustering in time and space is widely accepted, much more questionable is the existence of magnitude correlations. The standard approach generally assumes that magnitudes are independent and therefore in principle unpredictable. Here we show the existence of clustering in magnitude: earthquakes occur with higher probability close in time, space, and magnitude to previous events. More precisely, the next earthquake tends to have a magnitude similar but smaller than the previous one. A dynamical scaling relation between magnitude, time, and space distances reproduces the complex pattern of magnitude, spatial, and temporal correlations observed in experimental seismic catalogs.

  6. Symbolic Magnitude Modulates Perceptual Strength in Binocular Rivalry

    ERIC Educational Resources Information Center

    Paffen, Chris L. E.; Plukaard, Sarah; Kanai, Ryota

    2011-01-01

    Basic aspects of magnitude (such as luminance contrast) are directly represented by sensory representations in early visual areas. However, it is unclear how symbolic magnitudes (such as Arabic numerals) are represented in the brain. Here we show that symbolic magnitude affects binocular rivalry: perceptual dominance of numbers and objects of…

  7. 48 CFR 1852.236-74 - Magnitude of requirement.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Magnitude of requirement... 1852.236-74 Magnitude of requirement. As prescribed in 1836.570(d), insert the following provision: Magnitude of Requirement (DEC 1988) The Government estimated price range of this project is...

  8. 48 CFR 1852.236-74 - Magnitude of requirement.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 6 2013-10-01 2013-10-01 false Magnitude of requirement... 1852.236-74 Magnitude of requirement. As prescribed in 1836.570(d), insert the following provision: Magnitude of Requirement (DEC 1988) The Government estimated price range of this project is...

  9. 48 CFR 1852.236-74 - Magnitude of requirement.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Magnitude of requirement... 1852.236-74 Magnitude of requirement. As prescribed in 1836.570(d), insert the following provision: Magnitude of Requirement (DEC 1988) The Government estimated price range of this project is...

  10. 48 CFR 1852.236-74 - Magnitude of requirement.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Magnitude of requirement... 1852.236-74 Magnitude of requirement. As prescribed in 1836.570(d), insert the following provision: Magnitude of Requirement (DEC 1988) The Government estimated price range of this project is...

  11. Sign-And-Magnitude Up/Down Counter

    NASA Technical Reports Server (NTRS)

    Cole, Steven W.

    1991-01-01

    Magnitude-and-sign counter includes conventional up/down counter for magnitude part and special additional circuitry for sign part. Negative numbers indicated more directly. Counter implemented by programming erasable programmable logic device (EPLD) or programmable logic array (PLA). Used in place of conventional up/down counter to provide sign and magnitude values directly to other circuits.

  12. Numerical Magnitude Processing in Children with Mild Intellectual Disabilities

    ERIC Educational Resources Information Center

    Brankaer, Carmen; Ghesquiere, Pol; De Smedt, Bert

    2011-01-01

    The present study investigated numerical magnitude processing in children with mild intellectual disabilities (MID) and examined whether these children have difficulties in the ability to represent numerical magnitudes and/or difficulties in the ability to access numerical magnitudes from formal symbols. We compared the performance of 26 children…

  13. 48 CFR 1852.236-74 - Magnitude of requirement.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Magnitude of requirement... 1852.236-74 Magnitude of requirement. As prescribed in 1836.570(d), insert the following provision: Magnitude of Requirement (DEC 1988) The Government estimated price range of this project is...

  14. Binocular disparity magnitude affects perceived depth magnitude despite inversion of depth order.

    PubMed

    Matthews, Harold; Hill, Harold; Palmisano, Stephen

    2011-01-01

    The hollow-face illusion involves a misperception of depth order: our perception follows our top-down knowledge that faces are convex, even though bottom-up depth information reflects the actual concave surface structure. While pictorial cues can be ambiguous, stereopsis should unambiguously indicate the actual depth order. We used computer-generated stereo images to investigate how, if at all, the sign and magnitude of binocular disparities affect the perceived depth of the illusory convex face. In experiment 1 participants adjusted the disparity of a convex comparison face until it matched a reference face. The reference face was either convex or hollow and had binocular disparities consistent with an average face or had disparities exaggerated, consistent with a face stretched in depth. We observed that apparent depth increased with disparity magnitude, even when the hollow faces were seen as convex (ie when perceived depth order was inconsistent with disparity sign). As expected, concave faces appeared flatter than convex faces, suggesting that disparity sign also affects perceived depth. In experiment 2, participants were presented with pairs of real and illusory convex faces. In each case, their task was to judge which of the two stimuli appeared to have the greater depth. Hollow faces with exaggerated disparities were again perceived as deeper. PMID:22132512

  15. Stress magnitudes in the crust: constraints from stress orientation and relative magnitude data

    USGS Publications Warehouse

    Zoback, M.L.; Magee, M.

    1991-01-01

    The World Stress Map Project is a global cooperative effort to compile and interpret data on the orientation and relative magnitudes of the contemporary in situ tectonic stress field in the Earth's lithosphere. The intraplate stress field in both the oceans and continents is largely compressional with one or both of the horizontal stresses greater than the vertical stress. The regionally uniform horizontal intraplate stress orientations are generally consistent with either relative or absolute plate motions indicating that plate-boundary forces dominate the stress distribution within the plates. Current models of stresses due to whole mantle flow inferred from seismic topography models predict a general compressional stress state within continents but do not match the broad-scale horizontal stress orientations. The broad regionally uniform intraplate stress orientations are best correlated with compressional plate-boundary forces and the geometry of the plate boundaries. -from Authors

  16. Comparison of local magnitude scales in Central Europe

    NASA Astrophysics Data System (ADS)

    Kysel, Robert; Kristek, Jozef; Moczo, Peter; Cipciar, Andrej; Csicsay, Kristian; Srbecky, Miroslav; Kristekova, Miriam

    2015-04-01

    Efficient monitoring of earthquakes and determination of their magnitudes are necessary for developing earthquake catalogues at a regional and national levels. Unification and homogenization of the catalogues in terms of magnitudes has great importance for seismic hazard assessment. Calibrated local earthquake magnitude scales are commonly used for determining magnitudes of regional earthquakes by all national seismological services in the Central Europe. However, at the local scale, each seismological service uses its own magnitude determination procedure. There is no systematic comparison of the approaches and there is no unified procedure. We present a comparison of the local magnitude scales used by the national seismological services of Slovakia (Geophysical Institute, Slovak Academy of Sciences), Czech Republic (Institute of Geophysics, Academy of Sciences of the Czech Republic), Austria (ZAMG), Hungary (Geodetic and Geophysical Institute, Hungarian Academy of Sciences) and Poland (Institute of Geophysics, Polish Academy of Sciences), and by the local network of seismic stations located around the Nuclear Power Plant Jaslovske Bohunice, Slovakia. The comparison is based on the national earthquake catalogues and annually published earthquake bulletins for the period from 1985 to 2011. A data set of earthquakes has been compiled based on identification of common events in the national earthquake catalogues and bulletins. For each pair of seismic networks, magnitude differences have been determined and investigated as a function of time. The mean and standard deviations of the magnitude differences as well as regression coefficients between local magnitudes from the national seismological networks have been computed. Results show relatively big scatter between different national local magnitudes and its considerable time variation. A conversion between different national local magnitudes in a scale 1:1 seems inappropriate, especially for the compilation of the

  17. Some Effects of Magnitude of Reinforcement on Persistence of Responding

    ERIC Educational Resources Information Center

    McComas, Jennifer J.; Hartman, Ellie C.; Jimenez, Angel

    2008-01-01

    The influence of magnitude of reinforcement was examined on both response rate and behavioral persistence. During Phase 1, a multiple schedule of concurrent reinforcement was implemented in which reinforcement for one response option was held constant at VI 30 s across both components, while magnitude of reinforcement for the other response option…

  18. Number Games, Magnitude Representation, and Basic Number Skills in Preschoolers

    ERIC Educational Resources Information Center

    Whyte, Jemma Catherine; Bull, Rebecca

    2008-01-01

    The effect of 3 intervention board games (linear number, linear color, and nonlinear number) on young children's (mean age = 3.8 years) counting abilities, number naming, magnitude comprehension, accuracy in number-to-position estimation tasks, and best-fit numerical magnitude representations was examined. Pre- and posttest performance was…

  19. The Weight of Time: Affordances for an Integrated Magnitude System

    ERIC Educational Resources Information Center

    Lu, Aitao; Mo, Lei; Hodges, Bert H.

    2011-01-01

    In five experiments we explored the effects of weight on time in different action contexts to test the hypothesis that an integrated magnitude system is tuned to affordances. Larger magnitudes generally seem longer; however, Lu and colleagues (2009) found that if numbers were presented as weights in a range heavy enough to affect lifting, the…

  20. The Effects of Reinforcer Magnitude on Timing in Rats

    ERIC Educational Resources Information Center

    Ludvig, Elliot A.; Conover, Kent; Shizgal, Peter

    2007-01-01

    The relation between reinforcer magnitude and timing behavior was studied using a peak procedure. Four rats received multiple consecutive sessions with both low and high levels of brain stimulation reward (BSR). Rats paused longer and had later start times during sessions when their responses were reinforced with low-magnitude BSR. When estimated…

  1. Reinforcement Magnitude: An Evaluation of Preference and Reinforcer Efficacy

    ERIC Educational Resources Information Center

    Trosclair-Lasserre, Nicole M.; Lerman, Dorothea C.; Call, Nathan A.; Addison, Laura R.; Kodak, Tiffany

    2008-01-01

    Consideration of reinforcer magnitude may be important for maximizing the efficacy of treatment for problem behavior. Nonetheless, relatively little is known about children's preferences for different magnitudes of social reinforcement or the extent to which preference is related to differences in reinforcer efficacy. The purpose of the current…

  2. Linear Numerical-Magnitude Representations Aid Children's Memory for Numbers

    ERIC Educational Resources Information Center

    Thompson, Clarissa A.; Siegler, Robert S.

    2010-01-01

    We investigated the relation between children's numerical-magnitude representations and their memory for numbers. Results of three experiments indicated that the more linear children's magnitude representations were, the more closely their memory of the numbers approximated the numbers presented. This relation was present for preschoolers and…

  3. Magnitude Knowledge: The Common Core of Numerical Development

    ERIC Educational Resources Information Center

    Siegler, Robert S.

    2016-01-01

    The integrated theory of numerical development posits that a central theme of numerical development from infancy to adulthood is progressive broadening of the types and ranges of numbers whose magnitudes are accurately represented. The process includes four overlapping trends: 1) representing increasingly precisely the magnitudes of non-symbolic…

  4. Magnitude Knowledge: The Common Core of Numerical Development

    ERIC Educational Resources Information Center

    Siegler, Robert S.

    2016-01-01

    The integrated theory of numerical development posits that a central theme of numerical development from infancy to adulthood is progressive broadening of the types and ranges of numbers whose magnitudes are accurately represented. The process includes four overlapping trends: (1) representing increasingly precisely the magnitudes of non-symbolic…

  5. Congruency Effects between Number Magnitude and Response Force

    ERIC Educational Resources Information Center

    Vierck, Esther; Kiesel, Andrea

    2010-01-01

    Numbers are thought to be represented in space along a mental left-right oriented number line. Number magnitude has also been associated with the size of grip aperture, which might suggest a connection between number magnitude and intensity. The present experiment aimed to confirm this possibility more directly by using force as a response…

  6. Multifractal detrended fluctuation analysis of Pannonian earthquake magnitude series

    NASA Astrophysics Data System (ADS)

    Telesca, Luciano; Toth, Laszlo

    2016-04-01

    The multifractality of the series of magnitudes of the earthquakes occurred in Pannonia region from 2002 to 2012 has been investigated. The shallow (depth less than 40 km) and deep (depth larger than 70 km) seismic catalogues were analysed by using the multifractal detrended fluctuation analysis. The shallow and deep catalogues are characterized by different multifractal properties: (i) the magnitudes of the shallow events are weakly persistent, while those of the deep ones are almost uncorrelated; (ii) the deep catalogue is more multifractal than the shallow one; (iii) the magnitudes of the deep catalogue are characterized by a right-skewed multifractal spectrum, while that of the shallow magnitude is rather symmetric; (iv) a direct relationship between the b-value of the Gutenberg-Richter law and the multifractality of the magnitudes is suggested.

  7. Reinforcement Magnitude: An Evaluation of Preference and Reinforcer Efficacy

    PubMed Central

    Trosclair-Lasserre, Nicole M; Lerman, Dorothea C; Call, Nathan A; Addison, Laura R; Kodak, Tiffany

    2008-01-01

    Consideration of reinforcer magnitude may be important for maximizing the efficacy of treatment for problem behavior. Nonetheless, relatively little is known about children's preferences for different magnitudes of social reinforcement or the extent to which preference is related to differences in reinforcer efficacy. The purpose of the current study was to evaluate the relations among reinforcer magnitude, preference, and efficacy by drawing on the procedures and results of basic experimentation in this area. Three children who engaged in problem behavior that was maintained by social positive reinforcement (attention, access to tangible items) participated. Results indicated that preference for different magnitudes of social reinforcement may predict reinforcer efficacy and that magnitude effects may be mediated by the schedule requirement. PMID:18595284

  8. Induced earthquake magnitudes are as large as (statistically) expected

    NASA Astrophysics Data System (ADS)

    Elst, Nicholas J.; Page, Morgan T.; Weiser, Deborah A.; Goebel, Thomas H. W.; Hosseini, S. Mehran

    2016-06-01

    A major question for the hazard posed by injection-induced seismicity is how large induced earthquakes can be. Are their maximum magnitudes determined by injection parameters or by tectonics? Deterministic limits on induced earthquake magnitudes have been proposed based on the size of the reservoir or the volume of fluid injected. However, if induced earthquakes occur on tectonic faults oriented favorably with respect to the tectonic stress field, then they may be limited only by the regional tectonics and connectivity of the fault network. In this study, we show that the largest magnitudes observed at fluid injection sites are consistent with the sampling statistics of the Gutenberg-Richter distribution for tectonic earthquakes, assuming no upper magnitude bound. The data pass three specific tests: (1) the largest observed earthquake at each site scales with the log of the total number of induced earthquakes, (2) the order of occurrence of the largest event is random within the induced sequence, and (3) the injected volume controls the total number of earthquakes rather than the total seismic moment. All three tests point to an injection control on earthquake nucleation but a tectonic control on earthquake magnitude. Given that the largest observed earthquakes are exactly as large as expected from the sampling statistics, we should not conclude that these are the largest earthquakes possible. Instead, the results imply that induced earthquake magnitudes should be treated with the same maximum magnitude bound that is currently used to treat seismic hazard from tectonic earthquakes.

  9. Derivation of Johnson-Cousins Magnitudes from DSLR Camera Observations

    NASA Astrophysics Data System (ADS)

    Park, Woojin; Pak, Soojong; Shim, Hyunjin; Le, Huynh Anh N.; Im, Myungshin; Chang, Seunghyuk; Yu, Joonkyu

    2016-01-01

    The RGB Bayer filter system consists of a mosaic of R, G, and B filters on the grid of the photo sensors which typical commercial DSLR (Digital Single Lens Reflex) cameras and CCD cameras are equipped with. Lot of unique astronomical data obtained using an RGB Bayer filter system are available, including transient objects, e.g. supernovae, variable stars, and solar system bodies. The utilization of such data in scientific research requires that reliable photometric transformation methods are available between the systems. In this work, we develop a series of equations to convert the observed magnitudes in the RGB Bayer filter system (RB, GB, and BB) into the Johnson-Cousins BVR filter system (BJ, VJ, and RC). The new transformation equations derive the calculated magnitudes in the Johnson-Cousins filters (BJcal, VJcal, and RCcal) as functions of RGB magnitudes and colors. The mean differences between the transformed magnitudes and original magnitudes, i.e. the residuals, are (BJ - BJcal) = 0.064 mag, (VJ - VJcal) = 0.041 mag, and (RC - RCcal) = 0.039 mag. The calculated Johnson-Cousins magnitudes from the transformation equations show a good linear correlation with the observed Johnson-Cousins magnitudes.

  10. A scheme to set preferred magnitudes in the ISC Bulletin

    NASA Astrophysics Data System (ADS)

    Di Giacomo, Domenico; Storchak, Dmitry A.

    2016-04-01

    One of the main purposes of the International Seismological Centre (ISC) is to collect, integrate and reprocess seismic bulletins provided by agencies around the world in order to produce the ISC Bulletin. This is regarded as the most comprehensive bulletin of the Earth's seismicity, and its production is based on a unique cooperation in the seismological community that allows the ISC to complement the work of seismological agencies operating at global and/or local-regional scale. In addition, by using the seismic wave measurements provided by reporting agencies, the ISC computes, where possible, its own event locations and magnitudes such as short-period body wave m b and surface wave M S . Therefore, the ISC Bulletin contains the results of the reporting agencies as well as the ISC own solutions. Among the most used seismic event parameters listed in seismological bulletins, the event magnitude is of particular importance for characterizing a seismic event. The selection of a magnitude value (or multiple ones) for various research purposes or practical applications is not always a straightforward task for users of the ISC Bulletin and related products since a multitude of magnitude types is currently computed by seismological agencies (sometimes using different standards for the same magnitude type). Here, we describe a scheme that we intend to implement in routine ISC operations to mark the preferred magnitudes in order to help ISC users in the selection of events with magnitudes of their interest.

  11. Quantifying Heartbeat Dynamics by Magnitude and Sign Correlations

    NASA Astrophysics Data System (ADS)

    Ivanov, Plamen Ch.; Ashkenazy, Yosef; Kantelhardt, Jan W.; Stanley, H. Eugene

    2003-05-01

    We review a recently developed approach for analyzing time series with long-range correlations by decomposing the signal increment series into magnitude and sign series and analyzing their scaling properties. We show that time series with identical long-range correlations can exhibit different time organization for the magnitude and sign. We apply our approach to series of time intervals between consecutive heartbeats. Using the detrended fluctuation analysis method we find that the magnitude series is long-range correlated, while the sign series is anticorrelated and that both magnitude and sign series may have clinical applications. Further, we study the heartbeat magnitude and sign series during different sleep stages — light sleep, deep sleep, and REM sleep. For the heartbeat sign time series we find short-range anticorrelations, which are strong during deep sleep, weaker during light sleep and even weaker during REM sleep. In contrast, for the heartbeat magnitude time series we find long-range positive correlations, which are strong during REM sleep and weaker during light sleep. Thus, the sign and the magnitude series provide information which is also useful for distinguishing between different sleep stages.

  12. Regression between earthquake magnitudes having errors with known variances

    NASA Astrophysics Data System (ADS)

    Pujol, Jose

    2016-07-01

    Recent publications on the regression between earthquake magnitudes assume that both magnitudes are affected by error and that only the ratio of error variances is known. If X and Y represent observed magnitudes, and x and y represent the corresponding theoretical values, the problem is to find the a and b of the best-fit line y = a x + b. This problem has a closed solution only for homoscedastic errors (their variances are all equal for each of the two variables). The published solution was derived using a method that cannot provide a sum of squares of residuals. Therefore, it is not possible to compare the goodness of fit for different pairs of magnitudes. Furthermore, the method does not provide expressions for the x and y. The least-squares method introduced here does not have these drawbacks. The two methods of solution result in the same equations for a and b. General properties of a discussed in the literature but not proved, or proved for particular cases, are derived here. A comparison of different expressions for the variances of a and b is provided. The paper also considers the statistical aspects of the ongoing debate regarding the prediction of y given X. Analysis of actual data from the literature shows that a new approach produces an average improvement of less than 0.1 magnitude units over the standard approach when applied to Mw vs. mb and Mw vs. MS regressions. This improvement is minor, within the typical error of Mw. Moreover, a test subset of 100 predicted magnitudes shows that the new approach results in magnitudes closer to the theoretically true magnitudes for only 65 % of them. For the remaining 35 %, the standard approach produces closer values. Therefore, the new approach does not always give the most accurate magnitude estimates.

  13. Comparison of magnetic probe calibration at nano and millitesla magnitudes

    NASA Astrophysics Data System (ADS)

    Pahl, Ryan A.; Rovey, Joshua L.; Pommerenke, David J.

    2014-01-01

    Magnetic field probes are invaluable diagnostics for pulsed inductive plasma devices where field magnitudes on the order of tenths of tesla or larger are common. Typical methods of providing a broadband calibration of dot{{B}} probes involve either a Helmholtz coil driven by a function generator or a network analyzer. Both calibration methods typically produce field magnitudes of tens of microtesla or less, at least three and as many as six orders of magnitude lower than their intended use. This calibration factor is then assumed constant regardless of magnetic field magnitude and the effects of experimental setup are ignored. This work quantifies the variation in calibration factor observed when calibrating magnetic field probes in low field magnitudes. Calibration of two dot{{B}} probe designs as functions of frequency and field magnitude are presented. The first dot{{B}} probe design is the most commonly used design and is constructed from two hand-wound inductors in a differential configuration. The second probe uses surface mounted inductors in a differential configuration with balanced shielding to further reduce common mode noise. Calibration factors are determined experimentally using an 80.4 mm radius Helmholtz coil in two separate configurations over a frequency range of 100-1000 kHz. A conventional low magnitude calibration using a vector network analyzer produced a field magnitude of 158 nT and yielded calibration factors of 15 663 ± 1.7% and 4920 ± 0.6% {T}/{V {s}} at 457 kHz for the surface mounted and hand-wound probes, respectively. A relevant magnitude calibration using a pulsed-power setup with field magnitudes of 8.7-354 mT yielded calibration factors of 14 615 ± 0.3% and 4507 ± 0.4% {T}/{V {s}} at 457 kHz for the surface mounted inductor and hand-wound probe, respectively. Low-magnitude calibration resulted in a larger calibration factor, with an average difference of 9.7% for the surface mounted probe and 12.0% for the hand-wound probe. The

  14. Magnitude-frequency distribution of volcanic explosion earthquakes

    NASA Astrophysics Data System (ADS)

    Nishimura, Takeshi; Iguchi, Masato; Hendrasto, Mohammad; Aoyama, Hiroshi; Yamada, Taishi; Ripepe, Maurizio; Genco, Riccardo

    2016-07-01

    Magnitude-frequency distributions of volcanic explosion earthquakes that are associated with occurrences of vulcanian and strombolian eruptions, or gas burst activity, are examined at six active volcanoes. The magnitude-frequency distribution at Suwanosejima volcano, Japan, shows a power-law distribution, which implies self-similarity in the system, as is often observed in statistical characteristics of tectonic and volcanic earthquakes. On the other hand, the magnitude-frequency distributions at five other volcanoes, Sakurajima and Tokachi-dake in Japan, Semeru and Lokon in Indonesia, and Stromboli in Italy, are well explained by exponential distributions. The statistical features are considered to reflect source size, as characterized by a volcanic conduit or chamber. Earthquake generation processes associated with vulcanian, strombolian and gas burst events are different from those of eruptions ejecting large amounts of pyroclasts, since the magnitude-frequency distribution of the volcanic explosivity index is generally explained by the power law.

  15. Reinforcement magnitude and responding during treatment with differential reinforcement.

    PubMed Central

    Lerman, Dorothea C; Kelley, Michael E; Vorndran, Christina M; Kuhn, Stephanie A C; LaRue, Robert H

    2002-01-01

    Basic findings indicate that the amount or magnitude of reinforcement can influence free-operant responding prior to and during extinction. In this study, the relation between reinforcement magnitude and adaptive behavior was evaluated with 3 children as part of treatment with differential reinforcement. In the first experiment, a communicative response was shaped and maintained by the same reinforcer that was found to maintain problem behavior. Two reinforcement magnitudes (20-s or 60-s access to toys or escape from demands) were compared and found to be associated with similar levels of resistance to extinction. The relation between reinforcement magnitude and response maintenance was further evaluated in the second experiment by exposing the communicative response to 20-s or 300-s access to toys or escape. Results for 2 participants suggested that this factor may alter the duration of postreinforcement pauses. PMID:11936544

  16. When Should Zero Be Included on a Scale Showing Magnitude?

    ERIC Educational Resources Information Center

    Kozak, Marcin

    2011-01-01

    This article addresses an important problem of graphing quantitative data: should one include zero on the scale showing magnitude? Based on a real time series example, the problem is discussed and some recommendations are proposed.

  17. Reinforcement magnitude and responding during treatment with differential reinforcement.

    PubMed

    Lerman, Dorothea C; Kelley, Michael E; Vorndran, Christina M; Kuhn, Stephanie A C; LaRue, Robert H

    2002-01-01

    Basic findings indicate that the amount or magnitude of reinforcement can influence free-operant responding prior to and during extinction. In this study, the relation between reinforcement magnitude and adaptive behavior was evaluated with 3 children as part of treatment with differential reinforcement. In the first experiment, a communicative response was shaped and maintained by the same reinforcer that was found to maintain problem behavior. Two reinforcement magnitudes (20-s or 60-s access to toys or escape from demands) were compared and found to be associated with similar levels of resistance to extinction. The relation between reinforcement magnitude and response maintenance was further evaluated in the second experiment by exposing the communicative response to 20-s or 300-s access to toys or escape. Results for 2 participants suggested that this factor may alter the duration of postreinforcement pauses.

  18. Constant-Magnitude Acceleration on a Curved Path.

    ERIC Educational Resources Information Center

    Herrick, David L.

    1996-01-01

    Presents the theory behind a two-dimensional curved path along which the magnitude of the acceleration vector remains constant for an object moving frictionlessly under the influence of gravity. (JRH)

  19. Magnitude knowledge: the common core of numerical development.

    PubMed

    Siegler, Robert S

    2016-05-01

    The integrated theory of numerical development posits that a central theme of numerical development from infancy to adulthood is progressive broadening of the types and ranges of numbers whose magnitudes are accurately represented. The process includes four overlapping trends: (1) representing increasingly precisely the magnitudes of non-symbolic numbers, (2) connecting small symbolic numbers to their non-symbolic referents, (3) extending understanding from smaller to larger whole numbers, and (4) accurately representing the magnitudes of rational numbers. The present review identifies substantial commonalities, as well as differences, in these four aspects of numerical development. With both whole and rational numbers, numerical magnitude knowledge is concurrently correlated with, longitudinally predictive of, and causally related to multiple aspects of mathematical understanding, including arithmetic and overall math achievement. Moreover, interventions focused on increasing numerical magnitude knowledge often generalize to other aspects of mathematics. The cognitive processes of association and analogy seem to play especially large roles in this development. Thus, acquisition of numerical magnitude knowledge can be seen as the common core of numerical development.

  20. Threshold magnitude for Ionospheric TEC response to earthquakes

    NASA Astrophysics Data System (ADS)

    Perevalova, N. P.; Sankov, V. A.; Astafyeva, E. I.; Zhupityaeva, A. S.

    2014-02-01

    We have analyzed ionospheric response to earthquakes with magnitudes of 4.1-8.8 which occurred under quiet geomagnetic conditions in different regions of the world (the Baikal region, Kuril Islands, Japan, Greece, Indonesia, China, New Zealand, Salvador, and Chile). This investigation relied on measurements of total electron content (TEC) variations made by ground-based dual-frequency GPS receivers. To perform the analysis, we selected earthquakes with permanent GPS stations installed close by. Data processing has revealed that after 4.1-6.3-magnitude earthquakes wave disturbances in TEC variations are undetectable. We have thoroughly analyzed publications over the period of 1965-2013 which reported on registration of wave TIDs after earthquakes. This analysis demonstrated that the magnitude of the earthquakes having a wave response in the ionosphere was no less than 6.5. Based on our results and on the data from other researchers, we can conclude that there is a threshold magnitude (near 6.5) below which there are no pronounced earthquake-induced wave TEC disturbances. The probability of detection of post-earthquake TIDs with a magnitude close to the threshold depends strongly on geophysical conditions. In addition, reliable identification of the source of such TIDs generally requires many GPS stations in an earthquake zone. At low magnitudes, seismic energy is likely to be insufficient to generate waves in the neutral atmosphere which are able to induce TEC disturbances observable at the level of background fluctuations.

  1. Magnitude knowledge: the common core of numerical development.

    PubMed

    Siegler, Robert S

    2016-05-01

    The integrated theory of numerical development posits that a central theme of numerical development from infancy to adulthood is progressive broadening of the types and ranges of numbers whose magnitudes are accurately represented. The process includes four overlapping trends: (1) representing increasingly precisely the magnitudes of non-symbolic numbers, (2) connecting small symbolic numbers to their non-symbolic referents, (3) extending understanding from smaller to larger whole numbers, and (4) accurately representing the magnitudes of rational numbers. The present review identifies substantial commonalities, as well as differences, in these four aspects of numerical development. With both whole and rational numbers, numerical magnitude knowledge is concurrently correlated with, longitudinally predictive of, and causally related to multiple aspects of mathematical understanding, including arithmetic and overall math achievement. Moreover, interventions focused on increasing numerical magnitude knowledge often generalize to other aspects of mathematics. The cognitive processes of association and analogy seem to play especially large roles in this development. Thus, acquisition of numerical magnitude knowledge can be seen as the common core of numerical development. PMID:27074723

  2. Local magnitude calibration of the Hellenic Unified Seismic Network

    NASA Astrophysics Data System (ADS)

    Scordilis, E. M.; Kementzetzidou, D.; Papazachos, B. C.

    2016-01-01

    A new relation is proposed for accurate determination of local magnitudes in Greece. This relation is based on a large number of synthetic Wood-Anderson (SWA) seismograms corresponding to 782 regional shallow earthquakes which occurred during the period 2007-2013 and recorded by 98 digital broad-band stations. These stations are installed and operated by the following: (a) the National Observatory of Athens (HL), (b) the Department of Geophysics of the Aristotle University of Thessaloniki (HT), (c) the Seismological Laboratory of the University of Athens (HA), and (d) the Seismological Laboratory of the Patras University (HP). The seismological networks of the above institutions constitute the recently (2004) established Hellenic Unified Seismic Network (HUSN). These records are used to calculate a refined geometrical spreading factor and an anelastic attenuation coefficient, representative for Greece and surrounding areas, proper for accurate calculation of local magnitudes in this region. Individual station corrections depending on the crustal structure variations in their vicinity and possible inconsistencies in instruments responses are also considered in order to further ameliorate magnitude estimation accuracy. Comparison of such calculated local magnitudes with corresponding original moment magnitudes, based on an independent dataset, revealed that these magnitude scales are equivalent for a wide range of values.

  3. Induced earthquake magnitudes are as large as (statistically) expected

    NASA Astrophysics Data System (ADS)

    van der Elst, N.; Page, M. T.; Weiser, D. A.; Goebel, T.; Hosseini, S. M.

    2015-12-01

    Key questions with implications for seismic hazard and industry practice are how large injection-induced earthquakes can be, and whether their maximum size is smaller than for similarly located tectonic earthquakes. Deterministic limits on induced earthquake magnitudes have been proposed based on the size of the reservoir or the volume of fluid injected. McGarr (JGR 2014) showed that for earthquakes confined to the reservoir and triggered by pore-pressure increase, the maximum moment should be limited to the product of the shear modulus G and total injected volume ΔV. However, if induced earthquakes occur on tectonic faults oriented favorably with respect to the tectonic stress field, then they may be limited only by the regional tectonics and connectivity of the fault network, with an absolute maximum magnitude that is notoriously difficult to constrain. A common approach for tectonic earthquakes is to use the magnitude-frequency distribution of smaller earthquakes to forecast the largest earthquake expected in some time period. In this study, we show that the largest magnitudes observed at fluid injection sites are consistent with the sampling statistics of the Gutenberg-Richter (GR) distribution for tectonic earthquakes, with no assumption of an intrinsic upper bound. The GR law implies that the largest observed earthquake in a sample should scale with the log of the total number induced. We find that the maximum magnitudes at most sites are consistent with this scaling, and that maximum magnitude increases with log ΔV. We find little in the size distribution to distinguish induced from tectonic earthquakes. That being said, the probabilistic estimate exceeds the deterministic GΔV cap only for expected magnitudes larger than ~M6, making a definitive test of the models unlikely in the near future. In the meantime, however, it may be prudent to treat the hazard from induced earthquakes with the same probabilistic machinery used for tectonic earthquakes.

  4. Parsing pain perception between nociceptive representation and magnitude estimation.

    PubMed

    Baliki, M N; Geha, P Y; Apkarian, A V

    2009-02-01

    Assessing the size of objects rapidly and accurately clearly has survival value. A central multisensory module for subjective magnitude assessment is therefore highly likely, suggested by psychophysical studies, and proposed on theoretical grounds. Given that pain perception is fundamentally an assessment of stimulus intensity, it must necessarily engage such a central module. Accordingly, we compared functional magnetic resonance imaging (fMRI) activity of pain magnitude ratings to matched visual magnitude ratings in 14 subjects. We show that brain activations segregate into two groups, one preferentially activated for pain and another equally activated for both visual and pain magnitude ratings. The properties of regions in the first group were consistent with encoding nociception, whereas those in the second group with attention and task control. Insular cortex responses similarly segregated to a pain-specific area and an area (extending to the lateral prefrontal cortex) conjointly representing perceived magnitudes for pain and vision. These two insular areas were differentiated by their relationship to task variance, ability to encode perceived magnitudes for each stimulus epoch, temporal delay differences, and brain intrinsic functional connectivity. In a second group of subjects (n=11) we contrasted diffusion tensor imaging-based white matter connectivity for these two insular areas and observed anatomical connectivity closely corresponding to the functional connectivity identified with fMRI. These results demonstrate that pain perception is due to the transformation of nociceptive representation into subjective magnitude assessment within the insula. Moreover, we argue that we have identified a multisensory cortical area for "how much" complementary and analogous to the "where" and "what" as described for central visual processing.

  5. Magnitude Characterization Using Complex Networks in Central Chile

    NASA Astrophysics Data System (ADS)

    Pasten, D.; Comte, D.; Munoz, V.

    2013-12-01

    Studies using complex networks are applied to many systems, like traffic, social networks, internet and earth science. In this work we make an analysis using complex networks applied to magnitude of seismicity in the central zone of Chile, we use the preferential attachment in order to construct a seismic network using local magnitudes and the hypocenters of a seismic data set in central Chile. In order to work with a complete catalogue in magnitude, the data associated with the linear part of the Gutenberg-Richter law, with magnitudes greater than 2.7, were taken. We then make a grid in space, so that each seismic event falls into a certain cell, depending on the location of its hypocenter. Now the network is constructed: the first node corresponds to the cell where the first seismic event occurs. The node has an associated number which is the magnitude of the event which occured in it, and a probability is assigned to the node. The probability is a nonlinear mapping of the magnitude (a Gaussian function was taken), so that nodes with lower magnitude events are more likely to be attached to. Each time a new node is added to the network, it is attached to the previous node which has the larger probability; the link is directed from the previous node to the new node. In this way, a directed network is constructed, with a ``preferential attachment''-like growth model, using the magnitudes as the parameter to determine the probability of attachment to future nodes. Several events could occur in the same node. In this case, the probability is calculated using the average of the magnitudes of the events occuring in that node. Once the directed network is finished, the corresponding undirected network is constructed, by making all links symmetric, and eliminating the loops which may appear when two events occur in the same cell. The resulting directed network is found to be scale free (with very low values of the power-law distribution exponent), whereas the undirected

  6. Zero Magnitude Effect for the Productivity of Triggered Tsunami Sources

    NASA Astrophysics Data System (ADS)

    Geist, E. L.

    2013-12-01

    The Epidemic Type Aftershock Sequence (ETAS) model is applied to tsunami events to explain previously observed temporal clustering of tsunami sources. Tsunami events are defined by National Geophysical Data Center (NGDC) tsunami database. For the ETAS analysis, the earthquake magnitude associated with each tsunami event in the NGDC database is replaced by the primary magnitude listed in the Centennial catalog up until 1976 and in the Global CMT catalog from 1976 through 2010. Tsunamis with a submarine landslide or volcanic component are included if they are accompanied by an earthquake, which is most often the case. Tsunami size is used as a mark for determining a tsunami-generating event, according to a minimum completeness level. The tsunami catalog is estimated to be complete for tsunami sizes greater than 1 m since 1900 and greater than 0.1 m since 1960. Of the five parameters in the temporal ETAS model (Ogata, 1988), the parameter that scales the magnitude dependence in the productivity of triggered events is the one that is most different from ETAS parameters derived from similar earthquake catalogs. Maximum likelihood estimates of this magnitude effect parameter is essentially zero, within 95% confidence, for both the 0.1 m and 1.0 m tsunami completeness levels. To explain this result, parameter estimates are determined for the Global CMT catalog under three tsunamigenic conditions: (1) M≥7 and focal depth ≤50 km, (2) submarine location, and (3) dominant component of dip slip. Successive subcatalogs are formed from the Global CMT catalog according to each of these conditions. The high magnitude threshold for tsunamigenesis alone (subcatalog 1) does not explain the zero magnitude effect. The zero magnitude effect also does not appear to be caused the smaller number of tsunamigenic events analyzed in comparison to earthquake catalogs with a similar magnitude threshold. ETAS parameter estimates from the subcatalog (3) with all three tsunamigenic conditions

  7. Deep photometry and integral magnitudes of 8 nearby galaxies

    NASA Astrophysics Data System (ADS)

    Georgiev, Ts. B.

    2016-02-01

    We estimated integral magnitudes of galaxies trying to include the contribution of the brightest part of their halos. We performed surface photometry based on (i) concentric elliptical rims, corresponding to the peripheral ellipticity of the image, (ii) median estimation of the mean value of the rim pixels, (iii) apparent radial brightness profiles, corresponding to the rim medians, and (iv) magnitude curves of growth, derived by numerical integrations of the apparent rim profiles, without preliminary background estimation and removal. Furthermore, we used the magnitude curves of growth to determine the integral magnitudes (limited by size and deepness of our frames) and compared them with the total magnitudes in the data base HyperLeda. Also, we used the rim-profiles to estimate the background level far enough from the galaxy center and we build (here—only for trial) the intrinsic radial profiles (with background removal). We apply this photometry on 8 nearby galaxies, observed with CCD in the system BVRC IC by the 50 cm Schmidt telescope of the Rozhen NAO in 2003-2004. We build radial profiles which occur to be as average 1.8 times (1.2-2.5 times) larger than in data base NED and of integral brightness that occurs to be about 1.4 times (1.2-1.7 times) higher than in data base HyperLeda. The relative brightness additions, found here, correlate with the color index and anti-correlate with the luminosity of the galaxy.

  8. Correlating Total Visual Magnitude Estimates and CCD Photometry for Comets

    NASA Astrophysics Data System (ADS)

    Kidger, Mark Richard

    2015-08-01

    A key facet of understanding the activity of comets is coverage of their light curve. For some comets such as 2P/Encke there is good light curve coverage from visual observers extending back over many returns over more than 2 centuries. However, in recent years, CCD photometry by amateur astronomers has become the dominant data source and the number of total visual magnitude estimates has reduced sharply, making comparison of recent and historical photometric data for comets increasingly difficult. The relationship between total visual magnitude estimates - dominated by the emission from the Swan bands of C2 - and CCD aperture photometry - dominated by the dust continuum - has been far from clear.This paper compares CCD aperture photometry and total visual magnitude for several recent well-observed bright comets, including C/2014 Q2 (Lovejoy), C/2012 S1 (ISON) and C/2011 L4 (PanSTARRS) using a consistent and homogeneous database of observations from (mainly) Spanish observers. For comets with a 1/r radial coma profile, good agreement is found between CCD aperture photometry and total visual magnitude estimates for a CCD aperture corresponding to a physical coma diameter of ≈105km.The relationship between the coma radial brightness slope and the equivalent physical aperture for CCD photometry to obtain agreement with total visual magnitude estimates is investigated.

  9. Newmark design spectra considering earthquake magnitudes and site categories

    NASA Astrophysics Data System (ADS)

    Li, Bo; Xie, Wei-Chau; Pandey, M. D.

    2016-09-01

    Newmark design spectra have been implemented in many building codes, especially in building codes for critical structures. Previous studies show that Newmark design spectra exhibit lower amplitudes at high frequencies and larger amplitudes at low frequencies in comparison with spectra developed by statistical methods. To resolve this problem, this study considers three suites of ground motions recorded at three types of sites. Using these ground motions, influences of the shear-wave velocity, earthquake magnitudes, source-to-site distances on the ratios of ground motion parameters are studied, and spectrum amplification factors are statistically calculated. Spectral bounds for combinations of three site categories and two cases of earthquake magnitudes are estimated. Site design spectrum coefficients for the three site categories considering earthquake magnitudes are established. The problems of Newmark design spectra could be resolved by using the site design spectrum coefficients to modify the spectral values of Newmark design spectra in the acceleration sensitive, velocity sensitive, and displacement sensitive regions.

  10. Absolute magnitude calibration using trigonometric parallax - Incomplete, spectroscopic samples

    NASA Technical Reports Server (NTRS)

    Ratnatunga, Kavan U.; Casertano, Stefano

    1991-01-01

    A new numerical algorithm is used to calibrate the absolute magnitude of spectroscopically selected stars from their observed trigonometric parallax. This procedure, based on maximum-likelihood estimation, can retrieve unbiased estimates of the intrinsic absolute magnitude and its dispersion even from incomplete samples suffering from selection biases in apparent magnitude and color. It can also make full use of low accuracy and negative parallaxes and incorporate censorship on reported parallax values. Accurate error estimates are derived for each of the fitted parameters. The algorithm allows an a posteriori check of whether the fitted model gives a good representation of the observations. The procedure is described in general and applied to both real and simulated data.

  11. A catalog of observed nuclear magnitudes of Jupiter family comets

    NASA Astrophysics Data System (ADS)

    Tancredi, G.; Fernández, J. A.; Rickman, H.; Licandro, J.

    2000-10-01

    A catalog of a sample of 105 Jupiter family (JF) comets (defined as those with Tisserand constants T > 2 and orbital periods P < 20 yr) is presented with our ``best estimates'' of their absolute nuclear magnitudes H_N = V(1,0,0). The catalog includes all the nuclear magnitudes reported after 1950 until August 1998 that appear in the International Comet Quarterly Archive of Cometary Photometric Data, the Minor Planet Center (MPC) data base, IAU Circulars, International Comet Quarterly, and a few papers devoted to some particular comets, together with our own observations. Photometric data previous to 1990 have mainly been taken from the Comet Light Curve Catalogue (CLICC) compiled by Kamél (\\cite{kamel}). We discuss the reliability of the reported nuclear magnitudes in relation to the inherent sources of errors and uncertainties, in particular the coma contamination often present even at large heliocentric distances. A large fraction of the JF comets of our sample indeed shows various degrees of activity at large heliocentric distances, which is correlated with recent downward jumps in their perihelion distances. The reliability of coma subtraction methods to compute the nuclear magnitude is also discussed. Most absolute nuclear magnitudes are found in the range 15 - 18, with no magnitudes fainter than H_N ~ 19.5. The catalog can be found at: http://www.fisica.edu.uy/ ~ gonzalo/catalog/. Table 2 and Appendix B are only available in electronic form at http://www.edpsciences.org Table 5 is also available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html

  12. Every reinforcer counts: reinforcer magnitude and local preference.

    PubMed Central

    Davison, Michael; Baum, William M

    2003-01-01

    Six pigeons were trained on concurrent variable-interval schedules. Sessions consisted of seven components, each lasting 10 reinforcers, with the conditions of reinforcement differing between components. The component sequence was randomly selected without replacement. In Experiment 1, the concurrent-schedule reinforcer ratios in components were all equal to 1.0, but across components reinforcer-magnitude ratios varied from 1:7 through 7:1. Three different overall reinforcer rates were arranged across conditions. In Experiment 2, the reinforcer-rate ratios varied across components from 27:1 to 1:27, and the reinforcer-magnitude ratios for each alternative were changed across conditions from 1:7 to 7:1. The results of Experiment 1 replicated the results for changing reinforcer-rate ratios across components reported by Davison and Baum (2000, 2002): Sensitivity to reinforcer-magnitude ratios increased with increasing numbers of reinforcers in components. Sensitivity to magnitude ratio, however, fell short of sensitivity to reinforcer-rate ratio. The degree of carryover from component to component depended on the reinforcer rate. Larger reinforcers produced larger and longer postreinforcer preference pulses than did smaller reinforcers. Similar results were found in Experiment 2, except that sensitivity to reinforcer magnitude was considerably higher and was greater for magnitudes that differed more from one another. Visit durations following reinforcers measured either as number of responses emitted or time spent responding before a changeover were longer following larger than following smaller reinforcers, and were longer following sequences of same reinforcers than following other sequences. The results add to the growing body of research that informs model building at local levels. PMID:13677611

  13. Magnitude comparison with different types of rational numbers.

    PubMed

    DeWolf, Melissa; Grounds, Margaret A; Bassok, Miriam; Holyoak, Keith J

    2014-02-01

    An important issue in understanding mathematical cognition involves the similarities and differences between the magnitude representations associated with various types of rational numbers. For single-digit integers, evidence indicates that magnitudes are represented as analog values on a mental number line, such that magnitude comparisons are made more quickly and accurately as the numerical distance between numbers increases (the distance effect). Evidence concerning a distance effect for compositional numbers (e.g., multidigit whole numbers, fractions and decimals) is mixed. We compared the patterns of response times and errors for college students in magnitude comparison tasks across closely matched sets of rational numbers (e.g., 22/37, 0.595, 595). In Experiment 1, a distance effect was found for both fractions and decimals, but response times were dramatically slower for fractions than for decimals. Experiments 2 and 3 compared performance across fractions, decimals, and 3-digit integers. Response patterns for decimals and integers were extremely similar but, as in Experiment 1, magnitude comparisons based on fractions were dramatically slower, even when the decimals varied in precision (i.e., number of place digits) and could not be compared in the same way as multidigit integers (Experiment 3). Our findings indicate that comparisons of all three types of numbers exhibit a distance effect, but that processing often involves strategic focus on components of numbers. Fractions impose an especially high processing burden due to their bipartite (a/b) structure. In contrast to the other number types, the magnitude values associated with fractions appear to be less precise, and more dependent on explicit calculation. PMID:23750968

  14. Origin of limiting magnitude counting triangles and squares

    NASA Astrophysics Data System (ADS)

    Roggemans, Paul

    2010-08-01

    Meteor astronomers worldwide struggled for over a century with the problem of how to calibrate visual meteor counts. Although the effect of variable sky conditions was already recognized in the earliest studies of meteor counts, it took until the end of the 1940s before the limiting magnitude was commonly considered as the parameter to calibrate the sky conditions. The brilliant idea to use counting areas in the sky for limiting magnitude determination was proposed by Hugo van Woerden in the 1950s. This method is still used today and helped the IMO to fulfill the expectations of Hugo van Woerden many years after it was first published.

  15. Toward Reconciling Magnitude Discrepancies Estimated from Paleoearthquake Data

    SciTech Connect

    N. Seth Carpenter; Suzette J. Payne; Annette L. Schafer

    2012-06-01

    We recognize a discrepancy in magnitudes estimated for several Basin and Range, U.S.A. faults. For example, magnitudes predicted for the Wasatch (Utah), Lost River (Idaho), and Lemhi (Idaho) faults from fault segment lengths (L{sub seg}) where lengths are defined between geometrical, structural, and/or behavioral discontinuities assumed to persistently arrest rupture, are consistently less than magnitudes calculated from displacements (D) along these same segments. For self-similarity, empirical relationships (e.g. Wells and Coppersmith, 1994) should predict consistent magnitudes (M) using diverse fault dimension values for a given fault (i.e. M {approx} L{sub seg}, should equal M {approx} D). Typically, the empirical relationships are derived from historical earthquake data and parameter values used as input into these relationships are determined from field investigations of paleoearthquakes. A commonly used assumption - grounded in the characteristic-earthquake model of Schwartz and Coppersmith (1984) - is equating L{sub seg} with surface rupture length (SRL). Many large historical events yielded secondary and/or sympathetic faulting (e.g. 1983 Borah Peak, Idaho earthquake) which are included in the measurement of SRL and used to derive empirical relationships. Therefore, calculating magnitude from the M {approx} SRL relationship using L{sub seg} as SRL leads to an underestimation of magnitude and the M {approx} L{sub seg} and M {approx} D discrepancy. Here, we propose an alternative approach to earthquake magnitude estimation involving a relationship between moment magnitude (Mw) and length, where length is L{sub seg} instead of SRL. We analyze seven historical, surface-rupturing, strike-slip and normal faulting earthquakes for which segmentation of the causative fault and displacement data are available and whose rupture included at least one entire fault segment, but not two or more. The preliminary Mw {approx} L{sub seg} results are strikingly consistent

  16. Standard magnitude prize reinforcers can be as efficacious as larger magnitude reinforcers in cocaine-dependent methadone patients

    PubMed Central

    Petry, Nancy M.; Alessi, Sheila M.; Barry, Danielle; Carroll, Kathleen M.

    2014-01-01

    Objective Contingency management (CM) reduces cocaine use in methadone patients, but only about 50% of patients respond to CM interventions. This study evaluated whether increasing magnitudes of reinforcement will improve outcomes. Methods Cocaine-dependent methadone patients (N = 240) were randomized to one of four 12-week treatment conditions: usual care (UC), UC plus “standard” prize CM in which average expected prize earnings were about $300, UC plus high magnitude prize CM in which average expected prize earnings were about $900, or UC plus voucher CM with an expected maximum of about $900 in vouchers. Results All three CM conditions yielded significant reductions in cocaine use relative to UC, with effect sizes (d) ranging from 0.38 to 0.59. No differences were noted between CM conditions, with at least 55% of patients in each CM condition achieving one week or more of cocaine abstinence versus 35% in UC. During the 12 weeks after the intervention ended, CM increased time until relapse relative to UC, but the effects of CM were no longer significant at a 12-month follow-up. Conclusions Providing the standard magnitude of $300 in prizes was as effective as larger magnitude CM in cocaine-dependent methadone patients in this study. Given its strong evidence base and relatively low costs, standard magnitude prize CM should be considered for adoption in methadone clinics to encourage cocaine abstinence, but new methods need to be developed to sustain abstinence. PMID:25198284

  17. Magnitude Estimation with Noisy Integrators Linked by an Adaptive Reference

    PubMed Central

    Thurley, Kay

    2016-01-01

    Judgments of physical stimuli show characteristic biases; relatively small stimuli are overestimated whereas relatively large stimuli are underestimated (regression effect). Such biases likely result from a strategy that seeks to minimize errors given noisy estimates about stimuli that itself are drawn from a distribution, i.e., the statistics of the environment. While being conceptually well described, it is unclear how such a strategy could be implemented neurally. The present paper aims toward answering this question. A theoretical approach is introduced that describes magnitude estimation as two successive stages of noisy (neural) integration. Both stages are linked by a reference memory that is updated with every new stimulus. The model reproduces the behavioral characteristics of magnitude estimation and makes several experimentally testable predictions. Moreover, the model identifies the regression effect as a means of minimizing estimation errors and explains how this optimality strategy depends on the subject's discrimination abilities and on the stimulus statistics. The latter influence predicts another property of magnitude estimation, the so-called range effect. Beyond being successful in describing decision-making, the present work suggests that noisy integration may also be important in processing magnitudes. PMID:26909028

  18. The Role of Executive Functions in Numerical Magnitude Skills

    ERIC Educational Resources Information Center

    Kolkman, Meijke E.; Hoijtink, Herbert J. A.; Kroesbergen, Evelyn H.; Leseman, Paul P. M.

    2013-01-01

    Executive functions (EF) are closely related to math performance. Little is known, however, about the role of EF in numerical magnitude skills (NS), although these skills are widely acknowledged to be important precursors of math learning. The current study focuses on the different roles of updating, shifting, and inhibition in NS. EF and NS were…

  19. The Magnitude of Premenstrual and Menstrual Mood Changes in Adolescents.

    ERIC Educational Resources Information Center

    Golub, Sharon; Murphy, Denise

    Frequent mood changes in adolescents are often attributed to the influence of shifting hormone levels. The presence and magnitude of menstrual-related mood changes in adolescent women were examined in 10th and 11th grade females (N=158) who completed the Menstrual Distress Questionnaire (MDQ). Self-reports of the onset date for the next two…

  20. A dissociation between symbolic number knowledge and analogue magnitude information.

    PubMed

    Polk, T A; Reed, C L; Keenan, J M; Hogarth, P; Anderson, C A

    2001-12-01

    Semantic understanding of numbers and related concepts can be dissociated from rote knowledge of arithmetic facts. However, distinctions among different kinds of semantic representations related to numbers have not been fully explored. Working with numbers and arithmetic requires representing semantic information that is both analogue (e.g., the approximate magnitude of a number) and symbolic (e.g., what / means). In this article, the authors describe a patient (MC) who exhibits a dissociation between tasks that require symbolic number knowledge (e.g., knowledge of arithmetic symbols including numbers, knowledge of concepts related to numbers such as rounding) and tasks that require an analogue magnitude representation (e.g., comparing size or frequency). MC is impaired on a variety of tasks that require symbolic number knowledge, but her ability to represent and process analogue magnitude information is intact. Her deficit in symbolic number knowledge extends to a variety of concepts related to numbers (e.g., decimal points, Roman numerals, what a quartet is) but not to any other semantic categories that we have tested. These findings suggest that symbolic number knowledge is a functionally independent component of the number processing system, that it is category specific, and that it is anatomically and functionally distinct from magnitude representations. PMID:11748908

  1. High magnitude head impacts experienced during youth football practices.

    PubMed

    Young, Tyler; Rowson, Steven; Duma, Stefan M

    2014-01-01

    To reduce the risk of concussion in the 3.5 million youth athletes who participate in organized football leagues in the United States each year, practice structure can be modified to decrease impact frequency and magnitude. The objective of this study is to identify activities that result in high magnitude head impacts in youth football players during practice. The HIT System was used to record the head acceleration magnitude, impact location on the helmet, and time of each impact for each game and practice players participated in. These data were used to quantify the head impact exposure associated with players between the ages of 9 and 11 years. Video footage recorded during each practice and game session was used to identify the activity associated with any impact above 45 g. The incidence rate of high magnitude impacts in various activities were compared by normalizing by the amount of time associated with each activity. It was determined that scrimmages accounted for 0.094 impacts greater than 45 g per minute in practices while contact drills contributed to 0.102 impacts greater than 45 g per minute during practices. The results of this study indicate future youth football practice modifications should focus on both scrimmages and contact drills. PMID:25405410

  2. Neural representations of magnitude for natural and rational numbers.

    PubMed

    DeWolf, Melissa; Chiang, Jeffrey N; Bassok, Miriam; Holyoak, Keith J; Monti, Martin M

    2016-11-01

    Humans have developed multiple symbolic representations for numbers, including natural numbers (positive integers) as well as rational numbers (both fractions and decimals). Despite a considerable body of behavioral and neuroimaging research, it is currently unknown whether different notations map onto a single, fully abstract, magnitude code, or whether separate representations exist for specific number types (e.g., natural versus rational) or number representations (e.g., base-10 versus fractions). We address this question by comparing brain metabolic response during a magnitude comparison task involving (on different trials) integers, decimals, and fractions. Univariate and multivariate analyses revealed that the strength and pattern of activation for fractions differed systematically, within the intraparietal sulcus, from that of both decimals and integers, while the latter two number representations appeared virtually indistinguishable. These results demonstrate that the two major notations formats for rational numbers, fractions and decimals, evoke distinct neural representations of magnitude, with decimals representations being more closely linked to those of integers than to those of magnitude-equivalent fractions. Our findings thus suggest that number representation (base-10 versus fractions) is an important organizational principle for the neural substrate underlying mathematical cognition.

  3. Strategy Use and Strategy Choice in Fraction Magnitude Comparison

    ERIC Educational Resources Information Center

    Fazio, Lisa K.; DeWolf, Melissa; Siegler, Robert S.

    2016-01-01

    We examined, on a trial-by-trial basis, fraction magnitude comparison strategies of adults with more and less mathematical knowledge. College students with high mathematical proficiency used a large variety of strategies that were well tailored to the characteristics of the problems and that were guaranteed to yield correct performance if executed…

  4. What Is the Meaning of the Physical Magnitude "Work"?

    ERIC Educational Resources Information Center

    Kanderakis, Nikos

    2014-01-01

    Usually, in physics textbooks, the physical magnitude "work" is introduced as the product of a force multiplied by its displacement, in relation to the transfer of energy. In other words, "work" is presented as an internal affair of physics theory, while its relation to the world of experience, that is its empirical meaning, is…

  5. Children's Sensitivity to Error Magnitude when Evaluating Informants

    ERIC Educational Resources Information Center

    Einav, Shiri; Robinson, Elizabeth J.

    2010-01-01

    Three experiments examined children's (N = 80; 40; 48) sensitivity to error magnitude as a measure of informants' past accuracy, and indication of future reliability. Experiments 1 and 2 assessed whether, in a forced-choice task, children would evaluate as better and show greater trust in an informant whose previous errors were consistently within…

  6. Asteroid magnitudes, UBV colors, and IRAS albedos and diameters

    NASA Technical Reports Server (NTRS)

    Tedesco, Edward F.

    1989-01-01

    This paper lists absolute magnitudes and slope parameters for known asteroids numbered through 3318. The values presented are those used in reducing asteroid IR flux data obtained with the IRAS. U-B colors are given for 938 asteroids, and B-V colors are given for 945 asteroids. The IRAS albedos and diameters are tabulated for 1790 asteroids.

  7. Discriminability and Sensitivity to Reinforcer Magnitude in a Detection Task

    ERIC Educational Resources Information Center

    Alsop, Brent; Porritt, Melissa

    2006-01-01

    Three pigeons discriminated between two sample stimuli (intensities of red light). The difficulty of the discrimination was varied over four levels. At each level, the relative reinforcer magnitude for the two correct responses was varied across conditions, and the reinforcer rates were equal. Within levels, discriminability between the sample…

  8. Fraction Development in Children: Importance of Building Numerical Magnitude Understanding

    ERIC Educational Resources Information Center

    Jordan, Nancy C.; Carrique, Jessica; Hansen, Nicole; Resnick, Ilyse

    2016-01-01

    This chapter situates fraction learning within the integrated theory of numerical development. We argue that the understanding of numerical magnitudes for whole numbers as well as for fractions is critical to fraction learning in particular and mathematics achievement more generally. Results from the Delaware Longitudinal Study, which examined…

  9. Bayesian Predictive Distribution for the Magnitude of the Largest Aftershock

    NASA Astrophysics Data System (ADS)

    Shcherbakov, R.

    2014-12-01

    Aftershock sequences, which follow large earthquakes, last hundreds of days and are characterized by well defined frequency-magnitude and spatio-temporal distributions. The largest aftershocks in a sequence constitute significant hazard and can inflict additional damage to infrastructure. Therefore, the estimation of the magnitude of possible largest aftershocks in a sequence is of high importance. In this work, we propose a statistical model based on Bayesian analysis and extreme value statistics to describe the distribution of magnitudes of the largest aftershocks in a sequence. We derive an analytical expression for a Bayesian predictive distribution function for the magnitude of the largest expected aftershock and compute the corresponding confidence intervals. We assume that the occurrence of aftershocks can be modeled, to a good approximation, by a non-homogeneous Poisson process with a temporal event rate given by the modified Omori law. We also assume that the frequency-magnitude statistics of aftershocks can be approximated by Gutenberg-Richter scaling. We apply our analysis to 19 prominent aftershock sequences, which occurred in the last 30 years, in order to compute the Bayesian predictive distributions and the corresponding confidence intervals. In the analysis, we use the information of the early aftershocks in the sequences (in the first 1, 10, and 30 days after the main shock) to estimate retrospectively the confidence intervals for the magnitude of the expected largest aftershocks. We demonstrate by analysing 19 past sequences that in many cases we are able to constrain the magnitudes of the largest aftershocks. For example, this includes the analysis of the Darfield (Christchurch) aftershock sequence. The proposed analysis can be used for the earthquake hazard assessment and forecasting associated with the occurrence of large aftershocks. The improvement in instrumental data associated with early aftershocks can greatly enhance the analysis and

  10. Apparent LFE Magnitude-Frequency Distributions and the Tremor Source

    NASA Astrophysics Data System (ADS)

    Rubin, A. M.; Bostock, M. G.

    2015-12-01

    Over a decade since its discovery, it is disconcerting that we know so little about the kinematics of the tremor source. One could say we are hampered by low signal-to-noise ratio, but often the LFE signal is large and the "noise" is just other LFEs, often nearly co-located. Here we exploit this feature to better characterize the tremor source. A quick examination of LFE catalogs shows, unsurprisingly, that detected magnitudes are large when the background tremor amplitude is large. A simple interpretation is that small LFEs are missed when tremor is loud. An unanswered question is whether, in addition, there is a paucity of small LFEs when tremor is loud. Because we have both the LFE Green's function (from stacks) and some minimum bound on the overall LFE rate (from our catalogs), tremor waveforms provide a consistency check on any assumed magnitude-frequency (M-f) distribution. Beneath southern Vancouver Island, the magnitudes of >10^5 LFEs range from about 1.2-2.4 (Bostock et al. 2015). Interpreted in terms of a power-law distribution, the b-value is >5. But missed small events make even this large value only a lower bound. Binning by background tremor amplitude, and assuming a time-invariant M-f distribution, the b-value increases to >7, implying (e.g.) more than 10 million M>1.2 events for every M=2.2 event. Such numbers are inconsistent with the observed modest increase in tremor amplitude with LFE magnitude, as well as with geodetically-allowable slips. Similar considerations apply to exponential and log-normal moment-frequency distributions. Our preliminary interpretation is that when LFE magnitudes are large, the same portion of the fault is producing larger LFEs, rather than a greater rate of LFEs pulled from the same distribution. If correct, this distinguishes LFEs from repeating earthquakes, where larger background fault slip rates lead not to larger earthquakes but to more frequent earthquakes of similar magnitude. One possible explanation, that LFEs

  11. Forecasting magnitude, time, and location of aftershocks for aftershock hazard

    NASA Astrophysics Data System (ADS)

    Chen, K.; Tsai, Y.; Huang, M.; Chang, W.

    2011-12-01

    In this study we investigate the spatial and temporal seismicity parameters of the aftershock sequence accompanying the 17:47 20 September 1999 (UTC) 7.45 Chi-Chi earthquake Taiwan. Dividing the epicentral zone into north of the epicenter, at the epicenter, and south of the epicenter, it is found that immediately after the earthquake the area close by the epicenter had a lower value than both the northern and southern sections. This pattern suggests that at the time of the Chi-Chi earthquake, the area close by the epicenter remained prone to large magnitude aftershocks and strong shaking. However, with time the value increases. An increasing value indicates a reduced likelihood of large magnitude aftershocks. The study also shows that the value is higher at the southern section of the epicentral zone, indicating a faster rate of decay in this section. The primary purpose of this paper is to design a predictive model for forecasting the magnitude, time, and location of aftershocks to large earthquakes. The developed model is presented and applied to the 17:47 20 September 1999 7.45 Chi-Chi earthquake Taiwan, and the 09:32 5 November 2009 (UTC) Nantou 6.19, and 00:18 4 March 2010 (UTC) Jiashian 6.49 earthquake sequences. In addition, peak ground acceleration trends for the Nantou and Jiashian aftershock sequences are predicted and compared to actual trends. The results of the estimated peak ground acceleration are remarkably similar to calculations from recorded magnitudes in both trend and level. To improve the predictive skill of the model for occurrence time, we use an empirical relation to forecast the time of aftershocks. The empirical relation improves time prediction over that of random processes. The results will be of interest to seismic mitigation specialists and rescue crews. We apply also the parameters and empirical relation from Chi-Chi aftershocks of Taiwan to forecast aftershocks with magnitude M > 6.0 of 05:46 11 March 2011 (UTC) Tohoku 9

  12. Behavior of induced microseismic events with large magnitude

    NASA Astrophysics Data System (ADS)

    Asanuma, H.; Nozaki, H.; Niitsuma, H.; Wyborn, D.; Baria, R.

    2006-12-01

    Hydraulic stimulation of geothermal and oil/gas reservoir is one of the conventional techniques used for enhancing the productivity from reservoirs. In most cases, the stimulation process induces microseismic events. Based on the activity, location, magnitude and source mechanism of such events, the 3D localization and characterization of the reservoir can be carried out with practical resolution. Typically, microseismic events from a reservoir have moment magnitudes of less than zero, and most of them are detectable only by downhole sensors with high sensitivity. However, it is known that some of these events have higher magnitudes and can be felt at the surface. These large events can be hazardous from an environmental point of view, while resulting in enhanced permeability in the reservoir at the same time. The authors have analyzed the spatio-temporal distribution, and source mechanism of such microseismic events having large magnitudes (big events) observed during the hydraulic stimulations at Australian hot fractured rock (HFR) site in the Cooper Basin (Asanuma et al., SEG Exp. Abst., 2004) and also at the European hot dry rock (HDR) site in Soultz, France (Asanuma et al., Trans. GRC, 2004). A comparison between the origin time of these big events and the hydraulic records showed that many of the big events occurred after the shut-ins at both the sites. Besides, during pumping, most of these events did not show a clear correlation to the wellhead pressure and the rate of pumping. In most cases, the source mechanism of the big events were consistent with the shear slip of a preexisting fracture. We have also found that some of the big events at the Australian site brought very clear extension of the seismic cloud into zones that were seismically silent before, suggesting that some kind of hydraulic barrier was overcome by these big events. The observational data also showed that the microseismic events at those sites originated mainly from a slip of asperities

  13. The magnitude distribution of earthquakes near Southern California faults

    USGS Publications Warehouse

    Page, M.T.; Alderson, D.; Doyle, J.

    2011-01-01

    We investigate seismicity near faults in the Southern California Earthquake Center Community Fault Model. We search for anomalously large events that might be signs of a characteristic earthquake distribution. We find that seismicity near major fault zones in Southern California is well modeled by a Gutenberg-Richter distribution, with no evidence of characteristic earthquakes within the resolution limits of the modern instrumental catalog. However, the b value of the locally observed magnitude distribution is found to depend on distance to the nearest mapped fault segment, which suggests that earthquakes nucleating near major faults are likely to have larger magnitudes relative to earthquakes nucleating far from major faults. Copyright 2011 by the American Geophysical Union.

  14. A Search for 23rd Magnitude Kuiper Belt Comets

    NASA Technical Reports Server (NTRS)

    Luu, Jane

    1997-01-01

    The goal of the project was to identify a statistically significant sample of large (200 km-sized) Kuiper Belt Objects (KBOs), by covering 10 sq. degrees of the sky to a red limiting magnitude m(sub R) = 23. This work differs from, but builds on, previous surveys of the outer solar system in that it will cover a large area to a limiting magnitude that is deep enough to guarantee positive results. The proposed work should provide us with a significant number of 200 km-size KBOs (approx. 20 are expected) for subsequent studies. Such a sample is crucial if we are to investigate the statistical properties of the Belt and its members. It was modified the original research strategy to accommodate unanticipated problems such as the urgent need for follow-up observations,the original goal was still reached: we have substantially increased the number of Kuiper Belt Objects brighter than 23rd mag.

  15. On the internal representation of numerical magnitude and physical size.

    PubMed

    Fitousi, Daniel

    2014-01-01

    A nascent idea in the numerical cognition literature--the analogical hypothesis (Pinel, Piazza, Bihan, & Dehaene, 2004)--assumes a common noisy code for the representation of symbolic (e.g., numerals) and nonsymbolic (e.g., numerosity, physical size, luminance) magnitudes. The present work subjected this assumption to various tests from the perspective of General Recognition Theory (GRT; Ashby &Townsend, 1986)--a multidimensional extension of Signal Detection Theory (Green & Swets, 1966). The GRT was applied to the dimensions of numerical magnitude and physical size with the following goals: (a) characterizing the internal representation of these dimensions in the psychological space, and (b) assessing various types of (in)dependence and separability governing the perception of these dimensions. The results revealed various violations of independence and separability with Stroop incongruent, but not with Stroop congruent stimuli. The outcome suggests that there are deep differences in architecture between Stroop congruent and incongruent stimuli that reach well beyond the semantic relationship involved.

  16. Una formalizacion tentativa del problema de la barrera linguistica (A Tentative Formalization of the Problem of Linguistic Barriers).

    ERIC Educational Resources Information Center

    Zierer, Ernesto

    1971-01-01

    The formulas presented in this paper provide the means for showing the ease with which scientific information can be passed from one language into another. The formulas are based on several factors. The linguistic barrier can be measured to illustrate the relative degree of difference between two languages based on a comparison of vocabulary,…

  17. Aportes del Aprendizaje Basado en Problemas (ABP) en la ensenanza de la Fisiologia Animal en un programa de Zootecnia

    NASA Astrophysics Data System (ADS)

    Reinartz-Estrada, Monica

    Based on difficulties observed on the subject of technical-scientific conceptualization and the integration of theory and practice in learning animal physiology for students in the Animal Science program at the National University of Colombia in Medellin, this research paper proposes a problem-based learning strategy founded on the method of Problem Based Learning (PBL), applied specifically to the issues of thermoregulation and physiological stress in domestic animals. In this case study, a sample size of eight students was presented with a pedagogical problem during the first session that would then be solved during the course. In order to evaluate the process, three surveys were conducted called Level Test Formulations (NF) performed at different times of the trial: one before beginning the topic (NF 1), one after three theoretical classes had been given and before beginning the fieldwork (NF 2), and another one after the end of the process (NF 3). Finally, individual interviews were conducted with each student to know the students' perceptions regarding the method. The information obtained was subjected to a qualitative analysis and categorization, using the QDA Miner program which reviewed and coded texts from the surveys and individual interviews, supplemented in turn, by field observation, analyzing the conceptual change, the theory-practice relationship and the correlation between the variables and categories established. Among the main results obtained, it should be noted that following the implementation of PBL in this Animal Physiology course, support for conceptual change was demonstrated and the formulated problem served as a connector between theory and practice. Moreover, there was a fusion of prior knowledge with newly acquired knowledge, meaningful learning, improvement in the level of conceptualization and an increase in the scientificness of definitions; it also led to problem-solving and overcoming epistemological obstacles such as multidisciplinarity and nonlinearity. As a result of this research, it is recommended that this method be evaluated in other topics related to Animal Physiology, in other sciences, in larger sample sizes, as well as to address the issue of evaluation applied directly to this method. Key words: Problem Based Learning (PBL), conceptual change, integration of theory and practice, significatif learning, animal physiology, thermoregulation, physiological stress.

  18. Temas y problemas del idioma espanol en la prensa (Spanish Language Topics and Problems in the Press).

    ERIC Educational Resources Information Center

    El Brocense; And Others

    1980-01-01

    This section consists of reprints on the following topics: (1) the misuse of "en"; (2) anglicisms; (3) widespread use of vulgar language; (4) an interview with Emilio Criado on Spanish language variation; (5) use of the feminine in professional titles; and (6) Spanish, the national language of Latin American countries. (AMH)

  19. Los problemas de contenido y de empleo del verbo haber (Problems of Meaning and Use of the Verb "Haber.")

    ERIC Educational Resources Information Center

    Perez Botero, Luis A.

    1975-01-01

    Discusses the derivation, meaning and both past and present uses of the Spanish verb "haber." The verb refers to relationships of possession, duration and existence, and is used as an auxiliary. Extant derivative forms of the verb in other languages and earlier Spanish meanings are noted. (Text is in Spanish.) (CHK)

  20. Order of magnitude dose reduction in intraoral radiography

    SciTech Connect

    Kircos, L.T.; Angin, L.L.; Lorton, L.

    1987-03-01

    This comparative clinical investigation concerns the radiation dose from intraoral radiography using E-speed film and rectangular and circular beam collimation. Dose to organs not of diagnostic importance (brain, lens of the eye, thyroid, and breast) is reduced by approximately an order of magnitude when rectangular collimation and E-speed film are used in periapical radiography. And dose to the thyroid and breast is further reduced by a third with the use of a full leaded apron and thyroid shield.

  1. Morphology and Absolute Magnitudes of the SDSS DR7 QSOs

    NASA Astrophysics Data System (ADS)

    Coelho, B.; Andrei, A. H.; Antón, S.

    2014-10-01

    The ESA mission Gaia will furnish a complete census of the Milky Way, delivering astrometrics, dynamics, and astrophysics information for 1 billion stars. Operating in all-sky repeated survey mode, Gaia will also provide measurements of extra-galactic objects. Among the later there will be at least 500,000 QSOs that will be used to build the reference frame upon which the several independent observations will be combined and interpreted. Not all the QSOs are equally suited to fulfill this role of fundamental, fiducial grid-points. Brightness, morphology, and variability define the astrometric error budget for each object. We made use of 3 morphological parameters based on the PSF sharpness, circularity and gaussianity, which enable us to distinguish the "real point-like" QSOs. These parameters are being explored on the spectroscopically certified QSOs of the SDSS DR7, to compare the performance against other morphology classification schemes, as well as to derive properties of the host galaxy. We present a new method, based on the Gaia quasar database, to derive absolute magnitudes, on the SDSS filters domain. The method can be extrapolated all over the optical window, including the Gaia filters. We discuss colors derived from SDSS apparent magnitudes and colors based on absolute magnitudes that we obtained tanking into account corrections for dust extinction, either intergalactic or from the QSO host, and for the Lyman α forest. In the future we want to further discuss properties of the host galaxies, comparing for e.g. the obtained morphological classification with the color, the apparent and absolute magnitudes, and the redshift distributions.

  2. Spatial patterns of landslide dimension: A tool for magnitude mapping

    NASA Astrophysics Data System (ADS)

    Catani, Filippo; Tofani, Veronica; Lagomarsino, Daniela

    2016-11-01

    The magnitude of mass movements, which may be expressed by their dimension in terms of area or volume, is an important component of intensity together with velocity. In the case of slow-moving deep-seated landslides, the expected magnitude is the prevalent parameter for defining intensity when assessed as a spatially distributed variable in a given area. In particular, the frequency-volume statistics of past landslides may be used to understand and predict the magnitude of new landslides and reactivations. In this paper we study the spatial properties of volume frequency distributions in the Arno river basin (Central Italy, about 9100 km2). The overall landslide inventory taken into account (around 27,500 events) shows a power-law scaling of volumes for values greater than a cutoff value of about 2 × 104 m3. We explore the variability of the power-law exponent in the geographic space by setting up local subsets of the inventory based on neighbourhoods with radii between 5 and 50 km. We found that the power-law exponent α varies according to geographic position and that the exponent itself can be treated as a random space variable with autocorrelation properties both at local and regional scale. We use this finding to devise a simple method to map the magnitude frequency distribution in space and to create maps of exceeding probability of landslide volume for risk analysis. We also study the causes of spatial variation of α by analysing the dependence of power-law properties on geological and geomorphological factors, and we find that structural settings and valley density exert a strong influence on mass movement dimensions.

  3. MAGNITUDE GAP STATISTICS AND THE CONDITIONAL LUMINOSITY FUNCTION

    SciTech Connect

    More, Surhud

    2012-12-20

    In a recent preprint, Hearin et al. (H12) suggest that the halo mass-richness calibration of clusters can be improved by using the difference in the magnitude of the brightest and the second brightest galaxy (magnitude gap) as an additional observable. They claim that their results are at odds with the results from Paranjape and Sheth (PS12) who show that the magnitude distribution of the brightest and second brightest galaxies can be explained based on order statistics of luminosities randomly sampled from the total galaxy luminosity function. We find that a conditional luminosity function (CLF) for galaxies which varies with halo mass, in a manner which is consistent with existing observations, naturally leads to a magnitude gap distribution which changes as a function of halo mass at fixed richness, in qualitative agreement with H12. We show that, in general, the luminosity distribution of the brightest and the second brightest galaxy depends upon whether the luminosities of galaxies are drawn from the CLF or the global luminosity function. However, we also show that the difference between the two cases is small enough to evade detection in the small sample investigated by PS12. This shows that the luminosity distribution is not the appropriate statistic to distinguish between the two cases, given the small sample size. We argue in favor of the CLF (and therefore H12) based upon its consistency with other independent observations, such as the kinematics of satellite galaxies, the abundance and clustering of galaxies, and the galaxy-galaxy lensing signal from the Sloan Digital Sky Survey.

  4. Estimating earthquake location and magnitude from seismic intensity data

    USGS Publications Warehouse

    Bakun, W.H.; Wentworth, C.M.

    1997-01-01

    Analysis of Modified Mercalli intensity (MMI) observations for a training set of 22 California earthquakes suggests a strategy for bounding the epicentral region and moment magnitude M from MMI observations only. We define an intensity magnitude MI that is calibrated to be equal in the mean to M. MI = mean (Mi), where Mi = (MMIi + 3.29 + 0.0206 * ??i)/1.68 and ??i is the epicentral distance (km) of observation MMIi. The epicentral region is bounded by contours of rms [MI] = rms (MI - Mi) - rms0 (MI - Mi-), where rms is the root mean square, rms0 (MI - Mi) is the minimum rms over a grid of assumed epicenters, and empirical site corrections and a distance weighting function are used. Empirical contour values for bounding the epicenter location and empirical bounds for M estimated from MI appropriate for different levels of confidence and different quantities of intensity observations are tabulated. The epicentral region bounds and MI obtained for an independent test set of western California earthquakes are consistent with the instrumental epicenters and moment magnitudes of these earthquakes. The analysis strategy is particularly appropriate for the evaluation of pre-1900 earthquakes for which the only available data are a sparse set of intensity observations.

  5. The Road to Convergence in Earthquake Frequency-Magnitude Statistics

    NASA Astrophysics Data System (ADS)

    Naylor, M.; Bell, A. F.; Main, I. G.

    2013-12-01

    The Gutenberg-Richter frequency-magnitude relation is a fundamental empirical law of seismology, but its form remains uncertain for rare extreme events. Convergence trends can be diagnostic of the nature of an underlying distribution and its sampling even before convergence has occurred. We examine the evolution of an information criteria metric applied to earthquake magnitude time series, in order to test whether the Gutenberg-Richter law can be rejecting in various earthquake catalogues. This would imply that the catalogue is starting to sample roll-off in the tail though it cannot yet identify the form of the roll-off. We compare bootstrapped synthetic Gutenberg-Richter and synthetic modified Gutenberg-Richter catalogues with the convergence trends observed in real earthquake data e.g. the global CMT catalogue, Southern California and mining/geothermal data. Whilst convergence in the tail remains some way off, we show that the temporal evolution of model likelihoods and parameters for the frequency-magnitude distribution of the global Harvard Centroid Moment Tensor catalogue is inconsistent with an unbounded GR relation, despite it being the preferred model at the current time. Bell, A. F., M. Naylor, and I. G. Main (2013), Convergence of the frequency-size distribution of global earthquakes, Geophys. Res. Lett., 40, 2585-2589, doi:10.1002/grl.50416.

  6. Typical magnitude and spatial extent of crowding in autism

    PubMed Central

    Freyberg, Jan; Robertson, Caroline E.; Baron-Cohen, Simon

    2016-01-01

    Enhanced spatial processing of local visual details has been reported in individuals with autism spectrum conditions (ASC), and crowding is postulated to be a mechanism that may produce this ability. However, evidence for atypical crowding in ASC is mixed, with some studies reporting a complete lack of crowding in autism and others reporting a typical magnitude of crowding between individuals with and without ASC. Here, we aim to disambiguate these conflicting results by testing both the magnitude and the spatial extent of crowding in individuals with ASC (N = 25) and age- and IQ-matched controls (N = 23) during an orientation discrimination task. We find a strong crowding effect in individuals with and without ASC, which falls off as the distance between target and flanker is increased. Both the magnitude and the spatial range of this effect were comparable between individuals with and without ASC. We also find typical (uncrowded) orientation discrimination thresholds in individuals with ASC. These findings suggest that the spatial extent of crowding is unremarkable in ASC, and is therefore unlikely to account for the visual symptoms reported in individuals with the diagnosis. PMID:26998801

  7. Threshold magnitudes for a multichannel correlation detector in background seismicity

    DOE PAGESBeta

    Carmichael, Joshua D.; Hartse, Hans

    2016-04-01

    Colocated explosive sources often produce correlated seismic waveforms. Multichannel correlation detectors identify these signals by scanning template waveforms recorded from known reference events against "target" data to find similar waveforms. This screening problem is challenged at thresholds required to monitor smaller explosions, often because non-target signals falsely trigger such detectors. Therefore, it is generally unclear what thresholds will reliably identify a target explosion while screening non-target background seismicity. Here, we estimate threshold magnitudes for hypothetical explosions located at the North Korean nuclear test site over six months of 2010, by processing International Monitoring System (IMS) array data with a multichannelmore » waveform correlation detector. Our method (1) accounts for low amplitude background seismicity that falsely triggers correlation detectors but is unidentifiable with conventional power beams, (2) adapts to diurnally variable noise levels and (3) uses source-receiver reciprocity concepts to estimate thresholds for explosions spatially separated from the template source. Furthermore, we find that underground explosions with body wave magnitudes mb = 1.66 are detectable at the IMS array USRK with probability 0.99, when using template waveforms consisting only of P -waves, without false alarms. We conservatively find that these thresholds also increase by up to a magnitude unit for sources located 4 km or more from the Feb.12, 2013 announced nuclear test.« less

  8. Improving Children’s Knowledge of Fraction Magnitudes

    PubMed Central

    Fazio, Lisa K.; Kennedy, Casey A.; Siegler, Robert S.

    2016-01-01

    We examined whether playing a computerized fraction game, based on the integrated theory of numerical development and on the Common Core State Standards’ suggestions for teaching fractions, would improve children’s fraction magnitude understanding. Fourth and fifth-graders were given brief instruction about unit fractions and played Catch the Monster with Fractions, a game in which they estimated fraction locations on a number line and received feedback on the accuracy of their estimates. The intervention lasted less than 15 minutes. In our initial study, children showed large gains from pretest to posttest in their fraction number line estimates, magnitude comparisons, and recall accuracy. In a more rigorous second study, the experimental group showed similarly large improvements, whereas a control group showed no improvement from practicing fraction number line estimates without feedback. The results provide evidence for the effectiveness of interventions emphasizing fraction magnitudes and indicate how psychological theories and research can be used to evaluate specific recommendations of the Common Core State Standards. PMID:27768756

  9. Correlating precursory declines in groundwater radon with earthquake magnitude.

    PubMed

    Kuo, T

    2014-01-01

    Both studies at the Antung hot spring in eastern Taiwan and at the Paihe spring in southern Taiwan confirm that groundwater radon can be a consistent tracer for strain changes in the crust preceding an earthquake when observed in a low-porosity fractured aquifer surrounded by a ductile formation. Recurrent anomalous declines in groundwater radon were observed at the Antung D1 monitoring well in eastern Taiwan prior to the five earthquakes of magnitude (Mw ): 6.8, 6.1, 5.9, 5.4, and 5.0 that occurred on December 10, 2003; April 1, 2006; April 15, 2006; February 17, 2008; and July 12, 2011, respectively. For earthquakes occurring on the longitudinal valley fault in eastern Taiwan, the observed radon minima decrease as the earthquake magnitude increases. The above correlation has been proven to be useful for early warning local large earthquakes. In southern Taiwan, radon anomalous declines prior to the 2010 Mw 6.3 Jiasian, 2012 Mw 5.9 Wutai, and 2012 ML 5.4 Kaohsiung earthquakes were also recorded at the Paihe spring. For earthquakes occurring on different faults in southern Taiwan, the correlation between the observed radon minima and the earthquake magnitude is not yet possible.

  10. Typical magnitude and spatial extent of crowding in autism.

    PubMed

    Freyberg, Jan; Robertson, Caroline E; Baron-Cohen, Simon

    2016-01-01

    Enhanced spatial processing of local visual details has been reported in individuals with autism spectrum conditions (ASC), and crowding is postulated to be a mechanism that may produce this ability. However, evidence for atypical crowding in ASC is mixed, with some studies reporting a complete lack of crowding in autism and others reporting a typical magnitude of crowding between individuals with and without ASC. Here, we aim to disambiguate these conflicting results by testing both the magnitude and the spatial extent of crowding in individuals with ASC (N = 25) and age- and IQ-matched controls (N = 23) during an orientation discrimination task. We find a strong crowding effect in individuals with and without ASC, which falls off as the distance between target and flanker is increased. Both the magnitude and the spatial range of this effect were comparable between individuals with and without ASC. We also find typical (uncrowded) orientation discrimination thresholds in individuals with ASC. These findings suggest that the spatial extent of crowding is unremarkable in ASC, and is therefore unlikely to account for the visual symptoms reported in individuals with the diagnosis.

  11. Relating Perturbation Magnitude to Temporal Gene Expression in Biological Systems

    SciTech Connect

    Callister, Stephen J.; Parnell, John J.; Pfrender, Michael E.; Hashsham, Syed

    2009-03-19

    A method to quantitatively relate stress to response at the level of gene expression is described using Saccharomyces cerevisiae as a model organism. Stress was defined as the magnitude of perturbation and strain was defined as the magnitude of cumulative response in terms of gene expression. Expression patterns of sixty genes previously reported to be significantly impacted by osmotic shock or belonging to the high-osmotic glycerol, glycerolipid metabolism, and glycolysis pathways were determined following perturbations of increasing sodium chloride concentrations (0, 0.5, 0.7, 1.0, 1.5, and 1.4 M). Expression of these genes was quantified temporally using reverse transcriptase real time polymerase chain reaction. The magnitude of cumulative response was obtained by calculating the total moment of area of the temporal response envelope for all the 60 genes, either together or for the set of genes related to each pathway. A non-linear relationship between stress and response was observed for the range of stress studied. This study examines a quantitative approach to quantify the strain at the level of gene expression to relate stress to strain in biological systems. The approach should be generally applicable to quantitatively evaluate the response of organisms to environmental change.

  12. The magnitude-redshift relation for 561 Abell clusters

    NASA Technical Reports Server (NTRS)

    Postman, M.; Huchra, J. P.; Geller, M. J.; Henry, J. P.

    1985-01-01

    The Hubble diagram for the 561 Abell clusters with measured redshifts has been examined using Abell's (1958) corrected photo-red magnitudes for the tenth-ranked cluster member (m10). After correction for the Scott effect and K dimming, the data are in good agreement with a linear magnitude-redshift relation with a slope of 0.2 out to z = 0.1. New redshift data are also presented for 20 Abell clusters. Abell's m10 is suitable for redshift estimation for clusters with m10 of no more than 16.5. At fainter m10, the number of foreground galaxies expected within an Abell radius is large enough to make identification of the tenth-ranked galaxy difficult. Interlopers bias the estimated redshift toward low values at high redshift. Leir and van den Bergh's (1977) redshift estimates suffer from this same bias but to a smaller degree because of the use of multiple cluster parameters. Constraints on deviations of cluster velocities from the mean cosmological flow require greater photometric accuracy than is provided by Abell's m10 magnitudes.

  13. The magnitude-redshift relation in a realistic inhomogeneous universe

    SciTech Connect

    Hada, Ryuichiro; Futamase, Toshifumi E-mail: tof@astr.tohoku.ac.jp

    2014-12-01

    The light rays from a source are subject to a local inhomogeneous geometry generated by inhomogeneous matter distribution as well as the existence of collapsed objects. In this paper we investigate the effect of inhomogeneities and the existence of collapsed objects on the propagation of light rays and evaluate changes in the magnitude-redshift relation from the standard relationship found in a homogeneous FRW universe. We give the expression of the correlation function and the variance for the perturbation of apparent magnitude, and calculate it numerically by using the non-linear matter power spectrum. We use the lognormal probability distribution function for the density contrast and spherical collapse model to truncate the power spectrum in order to estimate the blocking effect by collapsed objects. We find that the uncertainties in Ω{sub m} is ∼ 0.02, and that of w is ∼ 0.04 . We also discuss a possible method to extract these effects from real data which contains intrinsic ambiguities associated with the absolute magnitude.

  14. Magnitudes and timescales of total solar irradiance variability

    NASA Astrophysics Data System (ADS)

    Kopp, Greg

    2016-07-01

    The Sun's net radiative output varies on timescales of minutes to gigayears. Direct measurements of the total solar irradiance (TSI) show changes in the spatially- and spectrally-integrated radiant energy on timescales as short as minutes to as long as a solar cycle. Variations of ~0.01% over a few minutes are caused by the ever-present superposition of convection and oscillations with very large solar flares on rare occasion causing slightly-larger measurable signals. On timescales of days to weeks, changing photospheric magnetic activity affects solar brightness at the ~0.1% level. The 11-year solar cycle shows variations of comparable magnitude with irradiances peaking near solar maximum. Secular variations are more difficult to discern, being limited by instrument stability and the relatively short duration of the space-borne record. Historical reconstructions of the Sun's irradiance based on indicators of solar-surface magnetic activity, such as sunspots, faculae, and cosmogenic isotope records, suggest solar brightness changes over decades to millennia, although the magnitudes of these variations have high uncertainties due to the indirect historical records on which they rely. Stellar evolution affects yet longer timescales and is responsible for the greatest solar variabilities. In this manuscript I summarize the Sun's variability magnitudes over different temporal regimes and discuss the irradiance record's relevance for solar and climate studies as well as for detections of exo-solar planets transiting Sun-like stars.

  15. Does low magnitude earthquake ground shaking cause landslides?

    NASA Astrophysics Data System (ADS)

    Brain, Matthew; Rosser, Nick; Vann Jones, Emma; Tunstall, Neil

    2015-04-01

    Estimating the magnitude of coseismic landslide strain accumulation at both local and regional scales is a key goal in understanding earthquake-triggered landslide distributions and landscape evolution, and in undertaking seismic risk assessment. Research in this field has primarily been carried out using the 'Newmark sliding block method' to model landslide behaviour; downslope movement of the landslide mass occurs when seismic ground accelerations are sufficient to overcome shear resistance at the landslide shear surface. The Newmark method has the advantage of simplicity, requiring only limited information on material strength properties, landslide geometry and coseismic ground motion. However, the underlying conceptual model assumes that shear strength characteristics (friction angle and cohesion) calculated using conventional strain-controlled monotonic shear tests are valid under dynamic conditions, and that values describing shear strength do not change as landslide shear strain accumulates. Recent experimental work has begun to question these assumptions, highlighting, for example, the importance of shear strain rate and changes in shear strength properties following seismic loading. However, such studies typically focus on a single earthquake event that is of sufficient magnitude to cause permanent strain accumulation; by doing so, they do not consider the potential effects that multiple low-magnitude ground shaking events can have on material strength. Since such events are more common in nature relative to high-magnitude shaking events, it is important to constrain their geomorphic effectiveness. Using an experimental laboratory approach, we present results that address this key question. We used a bespoke geotechnical testing apparatus, the Dynamic Back-Pressured Shear Box (DynBPS), that uniquely permits more realistic simulation of earthquake ground-shaking conditions within a hillslope. We tested both cohesive and granular materials, both of which

  16. Suitability of rapid energy magnitude determinations for emergency response purposes

    NASA Astrophysics Data System (ADS)

    Di Giacomo, Domenico; Parolai, Stefano; Bormann, Peter; Grosser, Helmut; Saul, Joachim; Wang, Rongjiang; Zschau, Jochen

    2010-01-01

    It is common practice in the seismological community to use, especially for large earthquakes, the moment magnitude Mw as a unique magnitude parameter to evaluate the earthquake's damage potential. However, as a static measure of earthquake size, Mw does not provide direct information about the released seismic wave energy and its high frequency content, which is the more interesting information both for engineering purposes and for a rapid assessment of the earthquake's shaking potential. Therefore, we recommend to provide to disaster management organizations besides Mw also sufficiently accurate energy magnitude determinations as soon as possible after large earthquakes. We developed and extensively tested a rapid method for calculating the energy magnitude Me within about 10-15 min after an earthquake's occurrence. The method is based on pre-calculated spectral amplitude decay functions obtained from numerical simulations of Green's functions. After empirical validation, the procedure has been applied offline to a large data set of 767 shallow earthquakes that have been grouped according to their type of mechanism (strike-slip, normal faulting, thrust faulting, etc.). The suitability of the proposed approach is discussed by comparing our rapid Me estimates with Mw published by GCMT as well as with Mw and Me reported by the USGS. Mw is on average slightly larger than our Me for all types of mechanisms. No clear dependence on source mechanism is observed for our Me estimates. In contrast, Me from the USGS is generally larger than Mw for strike-slip earthquakes and generally smaller for the other source types. For ~67 per cent of the event data set our Me differs <= +/-0.3 magnitude units (m.u.) from the respective Me values published by the USGS. However, larger discrepancies (up to 0.8 m.u.) may occur for strike-slip events. A reason of that may be the overcorrection of the energy flux applied by the USGS for this type of earthquakes. We follow the original

  17. Estimating station noise thresholds for seismic magnitude bias elimination

    NASA Astrophysics Data System (ADS)

    Peacock, Sheila

    2014-05-01

    To eliminate the upward bias of seismic magnitude caused by censoring of signal hidden by noise, noise level at each station in a network must be estimated. Where noise levels are not measured directly, the method of Kelly and Lacoss (1969) has been used to infer them from bulletin data (Lilwall and Douglas 1984). To verify this estimate of noise level, noise thresholds of International Monitoring System (IMS) stations inferred from the International Data Centre (IDC) Reviewed Event Bulletin (REB) by the Kelly and Lacoss method for 2005-2013 are compared with direct measurements on (i) noise preceding first arrivals in filtered (0.8-4.5 Hz) IMS seismic data, and (ii) noise preceding the expected time of arrival of signals from events, where signal was not actually seen (values gathered by the IDC for maximum-likelihood magnitude calculation). For most stations the direct pre-signal noise measurements are ~0.25 units of log A/T lower than the Kelly&Lacoss thresholds; because the IDC automatic system declares a detection only when the short-term-average-to-long-term-average ratio threshold, which varies with station and frequency band between ~3-6, is exceeded. The noise values at expected times of non-observed signal arrival are ~0.15 units lower than the Kelly and Lacoss thresholds. Exceptions are caused by faulty channels being used for the direct noise or body-wave magnitude (mb) measurements or, for station ARCES and possibly FINES, SPITS and HFS, the wider filter used for signal amplitude than for signal detection admitting noise that swamped the signal. Abrupt changes in thresholds might show mis-documented sensor sensitivity changes at individual stations.

  18. Understanding high magnitude flood risk: evidence from the past

    NASA Astrophysics Data System (ADS)

    MacDonald, N.

    2009-04-01

    The average length of gauged river flow records in the UK is ~25 years, which presents a problem in determining flood risk for high-magnitude flood events. Severe floods have been recorded in many UK catchments during the past 10 years, increasing the uncertainty in conventional flood risk estimates based on river flow records. Current uncertainty in flood risk has implications for society (insurance costs), individuals (personal vulnerability) and water resource managers (flood/drought risk). An alternative approach is required which can improve current understanding of the flood frequency/magnitude relationship. Historical documentary accounts are now recognised as a valuable resource when considering the flood frequency/magnitude relationship, but little consideration has been given to the temporal and spatial distribution of these records. Building on previous research based on British rivers (urban centre): Ouse (York), Trent (Nottingham), Tay (Perth), Severn (Shrewsbury), Dee (Chester), Great Ouse (Cambridge), Sussex Ouse (Lewes), Thames (Oxford), Tweed (Kelso) and Tyne (Hexham), this work considers the spatial and temporal distribution of historical flooding. The selected sites provide a network covering many of the largest river catchments in Britain, based on urban centres with long detailed documentary flood histories. The chronologies offer an opportunity to assess long-term patterns of flooding, indirectly determining periods of climatic variability and potentially increased geomorphic activity. This research represents the first coherent large scale analysis undertaken of historical multi-catchment flood chronologies, providing an unparalleled network of sites, permitting analysis of the spatial and temporal distribution of historical flood patterns on a national scale.

  19. The color-magnitude distribution of small Jupiter Trojans

    NASA Astrophysics Data System (ADS)

    Wong, Ian; Brown, Michael E.; Emery, Joshua P.

    2014-11-01

    The Jupiter Trojans constitute a population of minor bodies that are situated in a 1:1 mean motion resonance with Jupiter and are concentrated in two swarms centered about the L4 and L5 Lagrangian points. Current theories of Solar System evolution describe a scenario in which the Trojans originated in a region beyond the primordial orbit of Neptune. It is hypothesized that during a subsequent period of chaotic dynamical disruptions in the outer Solar System, the primordial trans-Neptunian planetesimals were disrupted, and a fraction of them were scattered inwards and captured by Jupiter as Trojan asteroids, while the remaining objects were thrown outwards to larger heliocentric distances and eventually formed the Kuiper belt. If this is the case, a detailed study of the characteristics of Trojans may shed light on the relationships between the Trojans and other minor body populations in the outer Solar System, and more broadly, constrain models of late Solar System evolution. Several past studies of Trojans have revealed significant bimodalities with respect to various spectroscopic and photometric quantities, indicating the existence of two groupings among the Trojans - the so-called red and less-red sub-populations. In a previous work, we used primarily photometric data from the Sloan Digital Sky Survey to categorize several hundred Trojans with absolute magnitudes in the range H<12.3 into the two sub-populations. We demonstrated that the magnitude distributions of the color sub-populations are distinct to a high confidence level, suggesting that the red and less-red Trojans were formed in different locations and/or experienced different evolutionary histories. Most notably, we found that the discrepancy between the two color-magnitude distributions is concentrated at the faint end. Here, we present the results of a follow-up study, in which we analyze color measurements of a large number of small Trojans collected using the Suprime-Cam instrument on the Subaru

  20. Sequence data - Magnitude and implications of some ambiguities.

    NASA Technical Reports Server (NTRS)

    Holmquist, R.; Jukes, T. H.

    1972-01-01

    A stochastic model is applied to the divergence of the horse-pig lineage from a common ansestor in terms of the alpha and beta chains of hemoglobin and fibrinopeptides. The results are compared with those based on the minimum mutation distance model of Fitch (1972). Buckwheat and cauliflower cytochrome c sequences are analyzed to demonstrate their ambiguities. A comparative analysis of evolutionary rates for various proteins of horses and pigs shows that errors of considerable magnitude are introduced by Glx and Asx ambiguities into evolutionary conclusions drawn from sequences of incompletely analyzed proteins.

  1. The magnitude of impact damage on LDEF materials

    NASA Technical Reports Server (NTRS)

    Allbrooks, Martha; Atkinson, Dale

    1992-01-01

    The purpose of this report is to document the magnitude and types of impact damage to materials and systems on the LDEF. This report will provide insights which permit NASA and industry space-systems designers to more rapidly identify potential problems and hazards in placing a spacecraft in low-Earth orbit (LEO). This report is structured to provide (1) a background on LDEF, (2) an introduction to the LEO meteoroid and debris environments, and (3) descriptions of the types of damage caused by impacts into structural materials, and contamination caused by spallation and ejecta from impact events.

  2. Smoke optical depths - Magnitude, variability, and wavelength dependence

    NASA Technical Reports Server (NTRS)

    Pueschel, R. F.; Russell, P. B.; Colburn, D. A.; Ackerman, T. P.; Allen, D. A.

    1988-01-01

    An airborne autotracking sun-photometer has been used to measure magnitudes, temporal/spatial variabilities, and the wavelength dependence of optical depths in the near-ultraviolet to near-infrared spectrum of smoke from two forest fires and one jet fuel fire and of background air. Jet fuel smoke optical depths were found to be generally less wavelength dependent than background aerosol optical depths. Forest fire smoke optical depths, however, showed a wide range of wavelength depedences, such as incidents of wavelength-independent extinction.

  3. Magnitude of psychological gender differences. Another side to the story.

    PubMed

    Hyde, J S; Plant, E A

    1995-03-01

    A. H. Eagly (1995) argued that feminism created a political climate that has lead to research that inaccurately minimizes psychological gender differences. In this article, the authors assert that feminist psychologists do not have a uniform position on this issue, and that many have argued for large gender differences. Meta-analyses indicate great variability in the magnitude of gender differences across different behaviors. However, more psychological gender differences (25%) fall in the close-to-zero range than do other effects in psychology (6%). PMID:7726468

  4. Coastal erosion: Processes, timing and magnitudes at the bluff toe

    USGS Publications Warehouse

    Carter, C.H.; Guy, D.E., Jr.

    1988-01-01

    Five Lake Erie bluffs (one interlaminated clay and silt, three clay-rich diamicts and one shale) were surveyed at about 2-week intervals and after wind storms for up to 5 years. Erosion of the bluff toes along this low-energy coast occurred during northeast wind storms, which produced surges of up to 1 m and surf-zone waves of up to 1.2 m. Wave impact and/or uprush caused quarrying, which removed most of the toe material, and abrasion. There were from 1 to 23 erosion events/sites, with maximum magnitudes of erosion ranging from 12 to 55 cm/event. Timing and magnitude were linked to erodibility, maximum water level, storm surge, storm duration and beach width. A threshold maximum water level and a threshold surge were necessary for erosion. At these thresholds, the beach was submerged and wave energy was directly expended on the toe. Erosion did not take place when there was shorefast ice or when debris slopes shielded the toe from waves. The originally cohesive toe materials are easily eroded when they weather to an essentially noncohesive state. Wave erosion is the crucial erosion process; removal of material from the toe prevents the development of a stable slope. ?? 1988.

  5. Constraining explosive volcanism: subjective choices during estimates of eruption magnitude

    USGS Publications Warehouse

    Klawonn, Malin; Houghton, Bruce F.; Swanson, Don; Fagents, Sarah A.; Wessel, Paul; Wolfe, Cecily J.

    2014-01-01

    When estimating the magnitude of explosive eruptions from their deposits, individuals make three sets of critical choices with respect to input data: the spacing of sampling sites, the selection of contour intervals to constrain the field measurements, and the hand contouring of thickness/isomass data, respectively. Volcanologists make subjective calls, as there are no accepted published protocols and few accounts of how these choices will impact estimates of eruption magnitude. Here, for the first time, we took a set of unpublished thickness measurements from the 1959 Kīlauea Iki pyroclastic fall deposit and asked 101 volcanologists worldwide to hand contour the data. First, there were surprisingly consistent volume estimates across maps with three different sampling densities. Second, the variability in volume calculations imparted by individuals’ choices of contours is also surprisingly low and lies between s = 5 and 8 %. Third, volume estimation is insensitive to the extent to which different individuals “smooth” the raw data in constructing contour lines. Finally, large uncertainty is associated with the construction of the thinnest isopachs, which is likely to underestimate the actual trend of deposit thinning. The net result is that researchers can have considerable confidence in using volume or dispersal data from multiple authors and different deposits for comparative studies. These insights should help volcanologists around the world to optimize design and execution of field-based studies to characterize accurately the volume of pyroclastic deposits.

  6. Estimating the magnitude of food waste generated in South Africa.

    PubMed

    Oelofse, Suzan Hh; Nahman, Anton

    2013-01-01

    Throughout the developed world, food is treated as a disposable commodity. Between a third and half of all food produced for human consumption globally is estimated to be wasted. However, attempts to quantify the actual magnitude of food wasted globally are constrained by limited data, particularly from developing countries. This article attempts to quantify total food waste generation (including both pre-consumer food losses, as well as post-consumer food waste) in South Africa. The estimates are based on available food supply data for South Africa and on estimates of average food waste generation at each step of the food supply chain for sub-Saharan Africa. The preliminary estimate of the magnitude of food waste generation in South Africa is in the order of 9.04 million tonnes per annum. On a per capita basis, overall food waste in South Africa in 2007 is estimated at 177 kg/capita/annum and consumption waste at 7 kg/capita/annum. However, these preliminary figures should be used with caution and are subject to verification through ongoing research.

  7. Fault-Zone Maturity Defines Maximum Earthquake Magnitude

    NASA Astrophysics Data System (ADS)

    Bohnhoff, M.; Bulut, F.; Stierle, E.; Ben-Zion, Y.

    2014-12-01

    Estimating the maximum likely magnitude of future earthquakes on transform faults near large metropolitan areas has fundamental consequences for the expected hazard. Here we show that the maximum earthquakes on different sections of the North Anatolian Fault Zone (NAFZ) scale with the duration of fault zone activity, cumulative offset and length of individual fault segments. The findings are based on a compiled catalogue of historical earthquakes in the region, using the extensive literary sources that exist due to the long civilization record. We find that the largest earthquakes (M~8) are exclusively observed along the well-developed part of the fault zone in the east. In contrast, the western part is still in a juvenile or transitional stage with historical earthquakes not exceeding M=7.4. This limits the current seismic hazard to NW Turkey and its largest regional population and economical center Istanbul. Our findings for the NAFZ are consistent with data from the two other major transform faults, the San Andreas fault in California and the Dead Sea Transform in the Middle East. The results indicate that maximum earthquake magnitudes generally scale with fault-zone evolution.

  8. Strategy use and strategy choice in fraction magnitude comparison.

    PubMed

    Fazio, Lisa K; DeWolf, Melissa; Siegler, Robert S

    2016-01-01

    We examined, on a trial-by-trial basis, fraction magnitude comparison strategies of adults with more and less mathematical knowledge. College students with high mathematical proficiency used a large variety of strategies that were well tailored to the characteristics of the problems and that were guaranteed to yield correct performance if executed correctly. Students with less mathematical proficiency sometimes used strategies similar to those of the mathematically proficient students, but often used flawed strategies that yielded inaccurate performance. As predicted by overlapping waves theory, increases in accuracy and speed were related to differences in strategy use, strategy choice, and strategy execution. When asked to choose the best strategy from among 3 possibilities-the strategy the student originally used, a correct alternative, and an incorrect alternative-students with lower fraction knowledge rarely switched from an original incorrect strategy to a correct alternative. This finding suggests that use of poor fraction magnitude comparison strategies stems in large part from lack of conceptual understanding of the requirements of effective strategies, rather than difficulty recalling or generating such strategies. (PsycINFO Database Record

  9. A Study of LFE Magnitudes in Northern Cascadia

    NASA Astrophysics Data System (ADS)

    Bostock, M. G.

    2014-12-01

    We have compiled a comprehensive suite of ~250 low-frequency-earthquake (LFE) templates representing spatially distinct tremor sources on or near the plate boundary in northern Cascadia from northern Vancouver Island to southern Washington. Each template is assembled from 100's to 1000's of individual LFEs, representing a total of over 200,000 independent detections spanning a selection of episodic-tremor-and-slip (ETS) events between 2003 and 2013. On the basis of empirical evidence and analytical arguments, these templates can be considered as band-limited, empirical Green's functions excited from shallow-thrust point sources to station locations corresponding to a collection of temporary and permanent network sites. The high fidelity of template match-filtered detections enables precise alignment of individual LFE time series and analysis of LFE amplitudes. Upon correction for geometrical spreading, attenuation, free-surface magnification and radiation pattern, we solve for station-channel amplification factors and LFE magnitudes for all detections corresponding to a given ETS episode. We will present a spatio-temporal analysis of LFE magnitudes including their variability across different ETS events, their dependence in along-dip location, and their expression in different rupture modes, i.e. main front versus rapid tremor reversals of Houston [2011] versus small scale reversals of Rubin and Armbruster [2013].

  10. Predicted magnitudes and colors from cool-star model atmospheres

    NASA Astrophysics Data System (ADS)

    Johnson, H. R.; Steiman-Cameron, T. Y.

    1982-02-01

    An intercomparison of model stellar atmospheres and observations of real stars can lead to a better understanding of the relationship between the physical properties of stars and their observed radiative flux. In this spirit we have determined wide-band and narrow-band magnitudes and colors for a subset of models of K and M giant and supergiant stars selected from the grid of 40 models by Johnson, Bernat and Krupp (1980) (hereafter referred to as JBK). The 24 models selected have effective temperatures of 4000, 3800, 3600, 3400, 3200, 3000, 2750 and 2500 K and log g = 0, 1 or 2. Emergent energy fluxes (erg/ sq cm s A) were calculated at 9140 wavelengths for each model. These computed flux curves were folded through the transmission functions of Wing's 8-color system (Wing, 1971; White and Wing, 1978) and through Johnson's (1965) wide-band (BVRIJKLM) system. The calibration of the resultant magnitudes was made by using the absolute calibration of the flux curve of Vega by Schild, et al. (1971).

  11. Influence of storm magnitude and watershed size on runoff nonlinearity

    NASA Astrophysics Data System (ADS)

    Lee, Kwan Tun; Huang, Jen-Kuo

    2016-06-01

    The inherent nonlinear characteristics of the watershed runoff process related to storm magnitude and watershed size are discussed in detail in this study. The first type of nonlinearity is referred to rainfall-runoff dynamic process and the second type is with respect to a Power-law relation between peak discharge and upstream drainage area. The dynamic nonlinearity induced by storm magnitude was first demonstrated by inspecting rainfall-runoff records at three watersheds in Taiwan. Then the derivation of the watershed unit hydrograph (UH) using two linear hydrological models shows that the peak discharge and time to peak discharge that characterize the shape of UH vary event-to-event. Hence, the intention of deriving a unique and universal UH for all rainfall-runoff simulation cases is questionable. In contrast, the UHs by the other two adopted nonlinear hydrological models were responsive to rainfall intensity without relying on linear proportion principle, and are excellent in presenting dynamic nonlinearity. Based on the two-segment regression, the scaling nonlinearity between peak discharge and drainage area was investigated by analyzing the variation of Power-law exponent. The results demonstrate that the scaling nonlinearity is particularly significant for a watershed having larger area and subjecting to a small-size of storm. For three study watersheds, a large tributary that contributes relatively great drainage area or inflow is found to cause a transition break in scaling relationship and convert the scaling relationship from linearity to nonlinearity.

  12. Predicted magnitudes and colors from cool-star model atmospheres

    NASA Technical Reports Server (NTRS)

    Johnson, H. R.; Steiman-Cameron, T. Y.

    1981-01-01

    An intercomparison of model stellar atmospheres and observations of real stars can lead to a better understanding of the relationship between the physical properties of stars and their observed radiative flux. In this spirit we have determined wide-band and narrow-band magnitudes and colors for a subset of models of K and M giant and supergiant stars selected from the grid of 40 models by Johnson, Bernat and Krupp (1980) (hereafter referred to as JBK). The 24 models selected have effective temperatures of 4000, 3800, 3600, 3400, 3200, 3000, 2750 and 2500 K and log g = 0, 1 or 2. Emergent energy fluxes (erg/ sq cm s A) were calculated at 9140 wavelengths for each model. These computed flux curves were folded through the transmission functions of Wing's 8-color system (Wing, 1971; White and Wing, 1978) and through Johnson's (1965) wide-band (BVRIJKLM) system. The calibration of the resultant magnitudes was made by using the absolute calibration of the flux curve of Vega by Schild, et al. (1971).

  13. The absolute magnitude distribution of Kuiper Belt objects

    SciTech Connect

    Fraser, Wesley C.; Brown, Michael E.; Morbidelli, Alessandro; Parker, Alex; Batygin, Konstantin

    2014-02-20

    Here we measure the absolute magnitude distributions (H-distribution) of the dynamically excited and quiescent (hot and cold) Kuiper Belt objects (KBOs), and test if they share the same H-distribution as the Jupiter Trojans. From a compilation of all useable ecliptic surveys, we find that the KBO H-distributions are well described by broken power laws. The cold population has a bright-end slope, α{sub 1}=1.5{sub −0.2}{sup +0.4}, and break magnitude, H{sub B}=6.9{sub −0.2}{sup +0.1} (r'-band). The hot population has a shallower bright-end slope of, α{sub 1}=0.87{sub −0.2}{sup +0.07}, and break magnitude H{sub B}=7.7{sub −0.5}{sup +1.0}. Both populations share similar faint-end slopes of α{sub 2} ∼ 0.2. We estimate the masses of the hot and cold populations are ∼0.01 and ∼3 × 10{sup –4} M {sub ⊕}. The broken power-law fit to the Trojan H-distribution has α{sub 1} = 1.0 ± 0.2, α{sub 2} = 0.36 ± 0.01, and H {sub B} = 8.3. The Kolmogorov-Smirnov test reveals that the probability that the Trojans and cold KBOs share the same parent H-distribution is less than 1 in 1000. When the bimodal albedo distribution of the hot objects is accounted for, there is no evidence that the H-distributions of the Trojans and hot KBOs differ. Our findings are in agreement with the predictions of the Nice model in terms of both mass and H-distribution of the hot and Trojan populations. Wide-field survey data suggest that the brightest few hot objects, with H{sub r{sup ′}}≲3, do not fall on the steep power-law slope of fainter hot objects. Under the standard hierarchical model of planetesimal formation, it is difficult to account for the similar break diameters of the hot and cold populations given the low mass of the cold belt.

  14. The color-magnitude distribution of small Kuiper Belt objects

    NASA Astrophysics Data System (ADS)

    Wong, Ian; Brown, Michael E.

    2015-11-01

    Occupying a vast region beyond the ice giants is an extensive swarm of minor bodies known as the Kuiper Belt. Enigmatic in their formation, composition, and evolution, these Kuiper Belt objects (KBOs) lie at the intersection of many of the most important topics in planetary science. Improved instruments and large-scale surveys have revealed a complex dynamical picture of the Kuiper Belt. Meanwhile, photometric studies have indicated that small KBOs display a wide range of colors, which may reflect a chemically diverse initial accretion environment and provide important clues to constraining the surface compositions of these objects. Notably, some recent work has shown evidence for bimodality in the colors of non-cold classical KBOs, which would have major implications for the formation and subsequent evolution of the entire KBO population. However, these previous color measurements are few and mostly come from targeted observations of known objects. As a consequence, the effect of observational biases cannot be readily removed, preventing one from obtaining an accurate picture of the true color distribution of the KBOs as a whole.We carried out a survey of KBOs using the Hyper Suprime-Cam instrument on the 8.2-meter Subaru telescope. Our observing fields targeted regions away from the ecliptic plane so as to avoid contamination from cold classical KBOs. Each field was imaged in both the g’ and i’ filters, which allowed us to calculate the g’-i’ color of each detected object. We detected more than 500 KBOs over two nights of observation, with absolute magnitudes from H=6 to H=11. Our survey increases the number of KBOs fainter than H=8 with known colors by more than an order of magnitude. We find that the distribution of colors demonstrates a robust bimodality across the entire observed range of KBO sizes, from which we can categorize individual objects into two color sub-populations -- the red and very-red KBOs. We present the very first analysis of the

  15. Spatial Seismicity Rates and Maximum Magnitudes for Background Earthquakes

    USGS Publications Warehouse

    Petersen, Mark D.; Mueller, Charles S.; Frankel, Arthur D.; Zeng, Yuehua

    2008-01-01

    The background seismicity model is included to account for M 5.0 - 6.5 earthquakes on faults and for random M 5.0 ? 7.0 earthquakes that do not occur on faults included in the model (as in earlier models of Frankel et al., 1996, 2002 and Petersen et al., 1996). We include four different classes of earthquake sources in the California background seismicity model: (1) gridded (smoothed) seismicity, (2) regional background zones, (3) special fault zone models, and (4) shear zones (also referred to as C zones). The gridded (smoothed) seismicity model, the regional background zone model, and the special fault zones use a declustered earthquake catalog for calculation of earthquake rates. Earthquake rates in shear zones are estimated from the geodetically determined rate of deformation across an area of high strain rate. We use a truncated exponential (Gutenberg-Richter, 1944) magnitude-frequency distribution to account for earthquakes in the background models.

  16. Magnitude and Distribution of Flows into Northeastern Florida Bay

    USGS Publications Warehouse

    Patino, Eduardo; Hittle, Clinton D.

    2000-01-01

    Changes in water-management practices have been made to accommodate a large and rapidly growing urban population along the Atlantic Coast and to meet the demand for intensive agricultural activities. These changes have resulted in a highly managed hydrologic system consisting of numerous canals, levees, control structures, and pumping stations that have altered the hydrology of the Everglades and Florida Bay ecosystems. Over the past decade, Florida Bay has experienced sea-grass die-off and algal blooms, which are indicators of ecological change attributed primarily to the increase in salinity and nutrient content of bay waters. Because plans are to restore sheetflow in the Everglades wetlands to its natural state, water managers anticipate a change in the magnitude and timing of freshwater exiting the mainland through the creeks that cut through the embankment or as sheetflow into Florida Bay.

  17. Magnitude of visual accommodation to a head-up display

    NASA Technical Reports Server (NTRS)

    Leitner, E. F.; Haines, R. F.

    1981-01-01

    The virtual image symbology of head-up displays (HUDs) is presented at optical infinity to the pilot. This design feature is intended to help pilots maintain visual focus distance at optical infinity. However, the accommodation response could be nearer than optical infinity, due to an individual's dark focus response. Accommodation responses were measured of two age groups of airline pilots to: (1) static symbology on a HUD; (2) a landing site background at optical infinity; (3) the combination of the HUD symbology and the landing site background; and (4) complete darkness. Results indicate that magnitude of accommodation to HUD symbology, with and without the background, is not significantly different from an infinity focus response for either age group. The dark focus response is significantly closer than optical infinity for the younger pilots, but not the older pilots, a finding consistent with previous research.

  18. Aerogel Antennas Communications Study Using Error Vector Magnitude Measurements

    NASA Technical Reports Server (NTRS)

    Miranda, Felix A.; Mueller, Carl H.; Meador, Mary Ann B.

    2014-01-01

    This paper discusses an aerogel antennas communication study using error vector magnitude (EVM) measurements. The study was performed using 4x2 element polyimide (PI) aerogel-based phased arrays designed for operation at 5 GHz as transmit (Tx) and receive (Rx) antennas separated by a line of sight (LOS) distance of 8.5 meters. The results of the EVM measurements demonstrate that polyimide aerogel antennas work appropriately to support digital communication links with typically used modulation schemes such as QPSK and pi/4 DQPSK. As such, PI aerogel antennas with higher gain, larger bandwidth and lower mass than typically used microwave laminates could be suitable to enable aerospace-to-ground communication links with enough channel capacity to support voice, data and video links from cubesats, unmanned air vehicles (UAV), and commercial aircraft.

  19. THE EXTRAGALACTIC DISTANCE DATABASE: COLOR-MAGNITUDE DIAGRAMS

    SciTech Connect

    Jacobs, Bradley A.; Tully, R. Brent; Rizzi, Luca; Shaya, Edward J.; Makarov, Dmitry I.; Makarova, Lidia

    2009-08-15

    The color-magnitude diagrams/tip of the red giant branch (CMDs/TRGB) section of the Extragalactic Distance Database contains a compilation of observations of nearby galaxies from the Hubble Space Telescope. Approximately 250 (and increasing) galaxies in the Local Volume have CMDs and the stellar photometry tables used to produce them available through the Web. Various stellar populations that make up a galaxy are visible in the CMDs, but our primary purpose for collecting and analyzing these galaxy images is to measure the TRGB in each. We can estimate the distance to a galaxy by using stars at the TRGB as standard candles. In this paper, we describe the process of constructing the CMDs and make the results available to the public.

  20. Magnitude estimation reveals temporal binding at super-second intervals.

    PubMed

    Humphreys, Gruffydd R; Buehner, Marc J

    2009-10-01

    Several recent studies (e.g., Haggard, Aschersleben, Gehrke, & Prinz, 2002; Haggard & Clark, 2003; Haggard, Clark, & Kalogeras, 2002) have demonstrated a "Temporal Binding" effect in which the interval between an intentional action and its consequent outcome is subjectively shorter compared to equivalent intervals that do not involve intentional action. The bulk of the literature has relied on the "Libet Clock" (Libet, Gleason, Wright, & Pearl, 1983; but see also Engbert & Wohlschläger, 2007; Engbert, Wohlschläger, Thomas, & Haggard, 2007; Engbert, Wohlschläger, & Haggard, 2008). Here we demonstrate that Temporal Binding is a robust finding that can also be reliably achieved with a Magnitude Estimation procedure, and that occurs over intervals far greater than those previously explored. Implications for the underlying mechanisms are discussed.

  1. Membership probability via control-field colour-magnitude decontamination†

    NASA Astrophysics Data System (ADS)

    Corradi, Wagner J. B.; Maia, Francisco F. S.; Santos, João F. C.

    2010-01-01

    The fundamental physical parameters of open clusters are important tools to understand the formation and evolution of the Galactic disk and to test star-formation and evolution models. However, only a small fraction of the known open clusters in the Milky Way have precise determinations of distance, reddening, age, metallicity, radial velocity and proper motion. One of the major problems in determining these parameters lies in the difficulty to separate cluster members from field stars and to assign membership. We propose a decontamination method by employing 2mass data in the regions around the clusters NGC 1981, NGC 2516, NGC 6494 and M11. We present decontaminated colour-magnitude diagrams of these objects showing the membership probabilities and structural parameters as derived from King-profile fitting.

  2. Aerogel Antennas Communications Study Using Error Vector Magnitude Measurements

    NASA Technical Reports Server (NTRS)

    Miranda, Felix A.; Mueller, Carl H.; Meador, Mary Ann B.

    2014-01-01

    This presentation discusses an aerogel antennas communication study using error vector magnitude (EVM) measurements. The study was performed using 2x4 element polyimide (PI) aerogel-based phased arrays designed for operation at 5 GHz as transmit (Tx) and receive (Rx) antennas separated by a line of sight (LOS) distance of 8.5 meters. The results of the EVM measurements demonstrate that polyimide aerogel antennas work appropriately to support digital communication links with typically used modulation schemes such as QPSK and 4 DQPSK. As such, PI aerogel antennas with higher gain, larger bandwidth and lower mass than typically used microwave laminates could be suitable to enable aerospace-to- ground communication links with enough channel capacity to support voice, data and video links from CubeSats, unmanned air vehicles (UAV), and commercial aircraft.

  3. Nonlinear site response in medium magnitude earthquakes near Parkfield, California

    USGS Publications Warehouse

    Rubinstein, Justin L.

    2011-01-01

    Careful analysis of strong-motion recordings of 13 medium magnitude earthquakes (3.7 ≤ M ≤ 6.5) in the Parkfield, California, area shows that very modest levels of shaking (approximately 3.5% of the acceleration of gravity) can produce observable changes in site response. Specifically, I observe a drop and subsequent recovery of the resonant frequency at sites that are part of the USGS Parkfield dense seismograph array (UPSAR) and Turkey Flat array. While further work is necessary to fully eliminate other models, given that these frequency shifts correlate with the strength of shaking at the Turkey Flat array and only appear for the strongest shaking levels at UPSAR, the most plausible explanation for them is that they are a result of nonlinear site response. Assuming this to be true, the observation of nonlinear site response in small (M M 6.5 San Simeon earthquake and the 2004 M 6 Parkfield earthquake).

  4. What is the Meaning of the Physical Magnitude `Work'?

    NASA Astrophysics Data System (ADS)

    Kanderakis, Nikos

    2014-06-01

    Usually, in physics textbooks, the physical magnitude `work' is introduced as the product of a force multiplied by its displacement, in relation to the transfer of energy. In other words, `work' is presented as an internal affair of physics theory, while its relation to the world of experience, that is its empirical meaning, is missing. On the other hand, in the history of its creation, `work' was a concept that had empirical meaning from the start. It was constructed by engineers to measure the work (labor) of motor engines, men, and animals. Very soon however this initial meaning seems to vanish. In this article, it will be looked at how `work' is presented in physics textbooks, what was its initial meaning in the history of its formulation, under what circumstances this initial meaning faded, and how elements from the history of its creation can be used in the classroom to teach it.

  5. Magnitude and variation of prehistoric bird extinctions in the Pacific

    PubMed Central

    Duncan, Richard P.; Boyer, Alison G.; Blackburn, Tim M.

    2013-01-01

    The largest extinction event in the Holocene occurred on Pacific islands, where Late Quaternary fossils reveal the loss of thousands of bird populations following human colonization of the region. However, gaps in the fossil record mean that considerable uncertainty surrounds the magnitude and pattern of these extinctions. We use a Bayesian mark-recapture approach to model gaps in the fossil record and to quantify losses of nonpasserine landbirds on 41 Pacific islands. Two-thirds of the populations on these islands went extinct in the period between first human arrival and European contact, with extinction rates linked to island and species characteristics that increased susceptibility to hunting and habitat destruction. We calculate that human colonization of remote Pacific islands caused the global extinction of close to 1,000 species of nonpasserine landbird alone; nonpasserine seabird and passerine extinctions will add to this total. PMID:23530197

  6. Perceptual compression of magnitude-detected synthetic aperture radar imagery

    NASA Technical Reports Server (NTRS)

    Gorman, John D.; Werness, Susan A.

    1994-01-01

    A perceptually-based approach for compressing synthetic aperture radar (SAR) imagery is presented. Key components of the approach are a multiresolution wavelet transform, a bit allocation mask based on an empirical human visual system (HVS) model, and hybrid scalar/vector quantization. Specifically, wavelet shrinkage techniques are used to segregate wavelet transform coefficients into three components: local means, edges, and texture. Each of these three components is then quantized separately according to a perceptually-based bit allocation scheme. Wavelet coefficients associated with local means and edges are quantized using high-rate scalar quantization while texture information is quantized using low-rate vector quantization. The impact of the perceptually-based multiresolution compression algorithm on visual image quality, impulse response, and texture properties is assessed for fine-resolution magnitude-detected SAR imagery; excellent image quality is found at bit rates at or above 1 bpp along with graceful performance degradation at rates below 1 bpp.

  7. Kinetic changes in gait during low magnitude military load carriage.

    PubMed

    Majumdar, Deepti; Pal, Madhu Sudan; Pramanik, Anilendu; Majumdar, Dhurjati

    2013-01-01

    Indian infantry soldiers carry smaller magnitudes of loads for operational requirements. The ground reaction forces (GRFs) and impulse responses of 10 healthy male Indian infantry soldiers were collected while they walked carrying operational loads between 4.2 and 17.5 kg (6.5-27.2% of mean body weight (BW)) and a control condition of no external load (NL). The GRF and impulse components were normalised for BW, and data for each load condition were compared with NL in each side applying one-way analysis of variance followed by Dunnett's post hoc test. Right foot data were compared with corresponding left foot GRF data for all load conditions and NL. There were significant increases in vertical and anteroposterior GRFs with increase in load. Left and right feet GRF data in corresponding load conditions were significantly different in anteroposterior plane. No significant change was observed in the temporal components of support phase of gait. Changes in impulse parameter were observed in the anteroposterior and vertical planes while carrying load greater than 23 and 16.6% of BW for the right foot and left foot, respectively. Result indicates that smaller magnitudes of loads produced kinetic changes proportional to system weight, similar to heavier loads with the possibility of increased injury risk. Observed smaller asymmetric changes in gait may be considered as postural adjustment due to load. Unique physical characteristics of Indian soldiers and the probable design shortcomings of the existing backpack might have caused significant changes in GRF and peak impulse during smaller load carriage.

  8. Magnitude 8.1 Earthquake off the Solomon Islands

    NASA Technical Reports Server (NTRS)

    2007-01-01

    On April 1, 2007, a magnitude 8.1 earthquake rattled the Solomon Islands, 2,145 kilometers (1,330 miles) northeast of Brisbane, Australia. Centered less than ten kilometers beneath the Earth's surface, the earthquake displaced enough water in the ocean above to trigger a small tsunami. Though officials were still assessing damage to remote island communities on April 3, Reuters reported that the earthquake and the tsunami killed an estimated 22 people and left as many as 5,409 homeless. The most serious damage occurred on the island of Gizo, northwest of the earthquake epicenter, where the tsunami damaged the hospital, schools, and hundreds of houses, said Reuters. This image, captured by the Landsat-7 satellite, shows the location of the earthquake epicenter in relation to the nearest islands in the Solomon Island group. Gizo is beyond the left edge of the image, but its triangular fringing coral reefs are shown in the upper left corner. Though dense rain forest hides volcanic features from view, the very shape of the islands testifies to the geologic activity of the region. The circular Kolombangara Island is the tip of a dormant volcano, and other circular volcanic peaks are visible in the image. The image also shows that the Solomon Islands run on a northwest-southeast axis parallel to the edge of the Pacific plate, the section of the Earth's crust that carries the Pacific Ocean and its islands. The earthquake occurred along the plate boundary, where the Australia/Woodlark/Solomon Sea plates slide beneath the denser Pacific plate. Friction between the sinking (subducting) plates and the overriding Pacific plate led to the large earthquake on April 1, said the United States Geological Survey (USGS) summary of the earthquake. Large earthquakes are common in the region, though the section of the plate that produced the April 1 earthquake had not caused any quakes of magnitude 7 or larger since the early 20th century, said the USGS.

  9. Gaze direction affects the magnitude of face identity aftereffects.

    PubMed

    Kloth, Nadine; Jeffery, Linda; Rhodes, Gillian

    2015-01-01

    The face perception system partly owes its efficiency to adaptive mechanisms that constantly recalibrate face coding to our current diet of faces. Moreover, faces that are better attended produce more adaptation. Here, we investigated whether the social cues conveyed by a face can influence the amount of adaptation that face induces. We compared the magnitude of face identity aftereffects induced by adaptors with direct and averted gazes. We reasoned that faces conveying direct gaze may be more engaging and better attended and thus produce larger aftereffects than those with averted gaze. Using an adaptation duration of 5 s, we found that aftereffects for adaptors with direct and averted gazes did not differ (Experiment 1). However, when processing demands were increased by reducing adaptation duration to 1 s, we found that gaze direction did affect the magnitude of the aftereffect, but in an unexpected direction: Aftereffects were larger for adaptors with averted rather than direct gaze (Experiment 2). Eye tracking revealed that differences in looking time to the faces between the two gaze directions could not account for these findings. Subsequent ratings of the stimuli (Experiment 3) showed that adaptors with averted gaze were actually perceived as more expressive and interesting than adaptors with direct gaze. Therefore it appears that the averted-gaze faces were more engaging and better attended, leading to larger aftereffects. Overall, our results suggest that naturally occurring facial signals can modulate the adaptive impact a face exerts on our perceptual system. Specifically, the faces that we perceive as most interesting also appear to calibrate the organization of our perceptual system most strongly. PMID:25761338

  10. Regional Triggering of Volcanic Activity Following Large Magnitude Earthquakes

    NASA Astrophysics Data System (ADS)

    Hill-Butler, Charley; Blackett, Matthew; Wright, Robert

    2015-04-01

    There are numerous reports of a spatial and temporal link between volcanic activity and high magnitude seismic events. In fact, since 1950, all large magnitude earthquakes have been followed by volcanic eruptions in the following year - 1952 Kamchatka M9.2, 1960 Chile M9.5, 1964 Alaska M9.2, 2004 & 2005 Sumatra-Andaman M9.3 & M8.7 and 2011 Japan M9.0. While at a global scale, 56% of all large earthquakes (M≥8.0) in the 21st century were followed by increases in thermal activity. The most significant change in volcanic activity occurred between December 2004 and April 2005 following the M9.1 December 2004 earthquake after which new eruptions were detected at 10 volcanoes and global volcanic flux doubled over 52 days (Hill-Butler et al. 2014). The ability to determine a volcano's activity or 'response', however, has resulted in a number of disparities with <50% of all volcanoes being monitored by ground-based instruments. The advent of satellite remote sensing for volcanology has, therefore, provided researchers with an opportunity to quantify the timing, magnitude and character of volcanic events. Using data acquired from the MODVOLC algorithm, this research examines a globally comparable database of satellite-derived radiant flux alongside USGS NEIC data to identify changes in volcanic activity following an earthquake, February 2000 - December 2012. Using an estimate of background temperature obtained from the MODIS Land Surface Temperature (LST) product (Wright et al. 2014), thermal radiance was converted to radiant flux following the method of Kaufman et al. (1998). The resulting heat flux inventory was then compared to all seismic events (M≥6.0) within 1000 km of each volcano to evaluate if changes in volcanic heat flux correlate with regional earthquakes. This presentation will first identify relationships at the temporal and spatial scale, more complex relationships obtained by machine learning algorithms will then be examined to establish favourable

  11. Is Fish Response related to Velocity and Turbulence Magnitudes? (Invited)

    NASA Astrophysics Data System (ADS)

    Wilson, C. A.; Hockley, F. A.; Cable, J.

    2013-12-01

    Riverine fish are subject to heterogeneous velocities and turbulence, and may use this to their advantage by selecting regions which balance energy expenditure for station holding whilst maximising energy gain through feeding opportunities. This study investigated microhabitat selection by guppies (Poecilia reticulata) in terms of the three-dimensional velocity structure generated by idealised boulders in an experimental flume. Velocity and turbulence influenced intra-species variation in swimming behaviour with respect to size, sex and parasite intensity. With increasing body length, fish swam further and more frequently between boulder regions. Larger guppies spent more time in the high velocity and low turbulence region, whereas smaller guppies preferred the low velocity and high shear stress region directly behind the boulders. Male guppies selected the region of low velocity, indicating a possible reduced swimming ability due to hydrodynamic drag imposed by their fins. With increasing parasite (Gyrodactylus turnbulli) burden, fish preferentially selected the region of moderate velocity which had the lowest bulk measure of turbulence of all regions and was also the most spatially homogeneous velocity and turbulence region. Overall the least amount of time was spent in the recirculation zone which had the highest magnitude of shear stresses and mean vertical turbulent length scale to fish length ratio. Shear stresses were a factor of two greater than in the most frequented moderate velocity region, while mean vertical turbulent length scale to fish length ratio were six times greater. Indeed the mean longitudinal turbulent scale was 2-6 times greater than the fish length in all regions. While it is impossible to discriminate between these two turbulence parameters (shear stress and turbulent length to fish length ratio) in influencing the fish preference, our study infers that there is a bias towards fish spending more time in a region where both the bulk

  12. Absolute Magnitudes of Pan-STARRS PS1 Asteroids

    NASA Astrophysics Data System (ADS)

    Veres, Peter; Jedicke, R.; Fitzsimmons, A.; Denneau, L.; Wainscoat, R.; Bolin, B.; PS1SC Collaboration

    2013-10-01

    Absolute magnitude (H) of an asteroid is a fundamental parameter describing the size and the apparent brightness of the body. Because of its surface shape, properties and changing illumination, the brightness changes with the geometry and is described by the phase function governed by the slope parameter (G). Although many years have been spent on detailed observations of individual asteroids to provide H and G, vast majority of minor planets have H based on assumed G and due to the input photometry from multiple sources the errors of these values are unknown. We compute H of ~ 180 000 and G of few thousands asteroids observed with the Pan-STARRS PS1 telescope in well defined photometric systems. The mean photometric error is 0.04 mag. Because on average there are only 7 detections per asteroid in our sample, we employed a Monte Carlo (MC) technique to generate clones simulating all possible rotation periods, amplitudes and colors of detected asteroids. Known asteroid colors were taken from the SDSS database. We used debiased spin and amplitude distributions dependent on size, spectral class distributions of asteroids dependent on semi-major axis and starting values of G from previous works. H and G (G12 respectively) were derived by phase functions by Bowell et al. (1989) and Muinonen et al. (2010). We confirmed that there is a positive systematic offset between H based on PS1 asteroids and Minor Planet Center database up to -0.3 mag peaking at 14. Similar offset was first mentioned in the analysis of SDSS asteroids and was believed to be solved by weighting and normalizing magnitudes by observatory codes. MC shows that there is only a negligible difference between Bowell's and Muinonen's solution of H. However, Muinonen's phase function provides smaller errors on H. We also derived G and G12 for thousands of asteroids. For known spectral classes, slope parameters agree with the previous work in general, however, the standard deviation of G in our sample is twice

  13. VLF study of low magnitude Earthquakes (4.5

    NASA Astrophysics Data System (ADS)

    Wolbang, Daniel; Biernat, Helfried; Schwingenschuh, Konrad; Eichelberger, Hans; Prattes, Gustav; Besser, Bruno; Boudjada, Mohammed; Rozhnoi, Alexander; Solovieva, Maria; Biagi, Pier Francesco; Friedrich, Martin

    2014-05-01

    In the course of the European VLF/LF radio receiver network (International Network for Frontier Research on Earthquake Precursors, INFREP), radio signals in the frequency range from 10-50 kilohertz are received, continuously recorded (temporal resolution 20 seconds) and analyzed in the Graz/Austria knot. The radio signals are generated by dedicated distributed transmitters and detected by INFREP receivers in Europe. In case the signal is crossing an earthquake preparation zone, we are in principle able to detect seismic activity if the signal to noise ratio is high enough. The requirements to detect a seismic event with the radio link methods are given by the magnitude M of the Earthquake (EQ), the EQ preparation zone and the Fresnel zone. As pointed out by Rozhnoi et al. (2009), the VLF methods are suitable for earthquakes M>5.0. Furthermore, the VLF/LF radio link gets only disturbed if it is crossing the EQ preparation zone which is described by Molchanov et al. (2008). In the frame of this project I analyze low seismicity EQs (M≤5.6) in south/eastern Europe in the time period 2011-2013. My emphasis is on two seismic events with magnitudes 5.6 and 4.8 which we are not able to adequately characterize using our single parameter VLF method. I perform a fine structure analysis of the residua of various radio links crossing the area around the particular 2 EQs. Depending on the individual paths not all radio links are crossing the EQ preparation zone directly, so a comparative study is possible. As a comparison I analyze with the same method the already good described EQ of L'Aquila/Italy in 2009 with M=6.3 and radio links which are crossing directly the EQ preparation zone. In the course of this project we try to understand in more detail why it is so difficult to detect EQs with 4.5

  14. THE ABSOLUTE MAGNITUDE OF RRc VARIABLES FROM STATISTICAL PARALLAX

    SciTech Connect

    Kollmeier, Juna A.; Burns, Christopher R.; Thompson, Ian B.; Preston, George W.; Crane, Jeffrey D.; Madore, Barry F.; Morrell, Nidia; Prieto, José L.; Shectman, Stephen; Simon, Joshua D.; Villanueva, Edward; Szczygieł, Dorota M.; Gould, Andrew; Sneden, Christopher; Dong, Subo

    2013-09-20

    We present the first definitive measurement of the absolute magnitude of RR Lyrae c-type variable stars (RRc) determined purely from statistical parallax. We use a sample of 242 RRc variables selected from the All Sky Automated Survey for which high-quality light curves, photometry, and proper motions are available. We obtain high-resolution echelle spectra for these objects to determine radial velocities and abundances as part of the Carnegie RR Lyrae Survey. We find that M{sub V,RRc} = 0.59 ± 0.10 at a mean metallicity of [Fe/H] = –1.59. This is to be compared with previous estimates for RRab stars (M{sub V,RRab} = 0.76 ± 0.12) and the only direct measurement of an RRc absolute magnitude (RZ Cephei, M{sub V,RRc} = 0.27 ± 0.17). We find the bulk velocity of the halo relative to the Sun to be (W{sub π}, W{sub θ}, W{sub z} ) = (12.0, –209.9, 3.0) km s{sup –1} in the radial, rotational, and vertical directions with dispersions (σ{sub W{sub π}},σ{sub W{sub θ}},σ{sub W{sub z}}) = (150.4, 106.1, 96.0) km s{sup -1}. For the disk, we find (W{sub π}, W{sub θ}, W{sub z} ) = (13.0, –42.0, –27.3) km s{sup –1} relative to the Sun with dispersions (σ{sub W{sub π}},σ{sub W{sub θ}},σ{sub W{sub z}}) = (67.7,59.2,54.9) km s{sup -1}. Finally, as a byproduct of our statistical framework, we are able to demonstrate that UCAC2 proper-motion errors are significantly overestimated as verified by UCAC4.

  15. Analysis of the magnitude and frequency of floods in Colorado

    USGS Publications Warehouse

    Vaill, J.E.

    2000-01-01

    Regionalized flood-frequency relations need to be updated on a regular basis (about every 10 years). The latest study on regionalized flood-frequency equations for Colorado used data collected through water year 1981. A study was begun in 1994 by the U.S. Geological Survey, in cooperation with the Colorado Department of Transportation and the Bureau of Land Management, to include streamflow data collected since water year 1981 in the regionalized flood-frequency relations for Colorado. Longer periods of streamflow data and improved statistical analysis methods were used to define regression relations for estimating peak discharges having recurrence intervals of 2, 5, 10, 25, 50, 100, 200, and 500 years for unregulated streams in Colorado. The regression relations can be applied to sites of interest on gaged and ungaged streams. Ordinary least-squares regression was used to determine the best explanatory basin or climatic characteristic variables for each peak-discharge characteristic, and generalized least-squares regression was used to determine the best regression relation. Drainage-basin area, mean annual precipitation, and mean basin slope were determined to be statistically significant explanatory variables in the regression relations. Separate regression relations were developed for each of five distinct hydrologic regions in the State. The mean standard errors of estimate and average standard error of prediction associated with the regression relations generally ranged from 40 to 80 percent, except for one hydrologic region where the errors ranged from about 200 to 300 percent. Methods are presented for determining the magnitude of peak discharges for sites located at gaging stations, for sites located near gaging stations on the same stream when the ratio of drainage-basin areas is between about 0.5 and 1.5, and for sites where the drainage basin crosses a flood-region boundary or a State boundary. Methods are presented for determining the magnitude of peak

  16. Color-magnitude diagram of Palomar 4 - CCD photometry

    NASA Astrophysics Data System (ADS)

    Christian, C. A.; Heasley, J. N.

    1986-04-01

    Photometry of the globular cluster Pal 4 was obtained with the RCA CCD camera on the 3.6 m Canada-France-Hawaii Telescope on Mauna Kea. The color-magnitude diagram of the cluster shows a well-defined red horizontal branch, typical of outer halo systems, and an asymptotic giant branch well separated from the giant branch. The population of Pal 4 has been sampled to the main-sequence turnoff region (V = 25), allowing a detailed comparison of this distant object with theoretical models. The cluster parameters consistent with the CCD data are (m - M)0 = 20.1 + or - 0.1 mag, E(B - V) = 0.02 + or - 0.02, and Fe/H forbidden line = -1.7 + or - 0.1 with Y =0.2. The age of the cluster, determined by comparison with the isochrones of VandenBerg and Bell (1985) is consistent with an age of 15 + or - 1 Gyr, similar to inner halo globular clusters with ages determined in the same way.

  17. Effects of magnitude, depth, and time on cellular seismology forecasts

    NASA Astrophysics Data System (ADS)

    Fisher, Steven Wolf

    This study finds that, in most cases analyzed to date, past seismicity tends to delineate zones where future earthquakes are likely to occur. Network seismicity catalogs for the New Madrid Seismic Zone (NMSZ), Australia (AUS), California (CA), and Alaska (AK) are analyzed using modified versions of the Cellular Seismology (CS) method of Kafka (2002, 2007). The percentage of later occurring earthquakes located near earlier occurring earthquakes typically exceeds the expected percentage for randomly distributed later occurring earthquakes, and the specific percentage is influenced by several variables, including magnitude, depth, time, and tectonic setting. At 33% map area coverage, hit percents are typically 85-95% in the NMSZ, 50-60% in AUS, 75-85% in CA, and 75-85% in AK. Statistical significance testing is performed on trials analyzing the same variables so that the overall regions can be compared, although some tests are inconclusive due to the small number of earthquake sample sizes. These results offer useful insights into understanding the capabilities and limits of CS studies, which can provide guidance for improving the seismicity-based components of seismic hazard assessments.

  18. A method for determining the magnitude of Earth's gravity

    NASA Astrophysics Data System (ADS)

    Evans, A. G.

    1984-02-01

    An improved method is described that directly and continuously determines the magnitude of the earth's gravity in relation to a user platform at one or more selected points on or above the Earth's surface. An improved Global Positioning System (GPS) is used to carry out the method and is made up of a plurality of (24) continuously orbiting GPS satellites that are arranged into 3 groups of 8 satellites with each group or constellation being disposed in its respective plane of a series of 3 longitudinal planes. Each plane is arranged in predetermined angular and spatial relation to the Earth's equatorial plane and the other planes of the series. Any GPS satellite continuously transmits a pair of encoded RF signals at predetermined L-band frequencies. By virtue of this global arrangement of the 24 satellites, the antenna field of view of a user platform is capable of receiving at any time the encoded signals of at least six satellites. A geodetic receiver on the platform together with a receiver microprocessor, a navigation microprocessor, and a microcomputer progressively and continuously process signals received from the satellites for the ultimate purpose of comparing GPS determined vertical acceleration (that is normal to the Earth's modeled ellipsoid) with its platform-measured gravimeter acceleration (that is normal to the Earth's geoid) so as to determine, with greater accuracy, the gravity at one or more selected points.

  19. Radiocarbon test of earthquake magnitude at the Cascadia subduction zone

    USGS Publications Warehouse

    Atwater, B.F.; Stuiver, M.; Yamaguchi, D.K.

    1991-01-01

    THE Cascadia subduction zone, which extends along the northern Pacific coast of North America, might produce earthquakes of magnitude 8 or 9 ('great' earthquakes) even though it has not done so during the past 200 years of European observation 1-7. Much of the evidence for past Cascadia earthquakes comes from former meadows and forests that became tidal mudflats owing to abrupt tectonic subsidence in the past 5,000 years2,3,6,7. If due to a great earthquake, such subsidence should have extended along more than 100 km of the coast2. Here we investigate the extent of coastal subsidence that might have been caused by a single earthquake, through high-precision radiocarbon dating of coastal trees that abruptly subsided into the intertidal zone. The ages leave the great-earthquake hypothesis intact by limiting to a few decades the discordance, if any, in the most recent subsidence of two areas 55 km apart along the Washington coast. This subsidence probably occurred about 300 years ago.

  20. On the frequency-magnitude distribution of converging boundaries

    NASA Astrophysics Data System (ADS)

    Marzocchi, W.; Laura, S.; Heuret, A.; Funiciello, F.

    2011-12-01

    The occurrence of the last mega-thrust earthquake in Japan has clearly remarked the high risk posed to society by such events in terms of social and economic losses even at large spatial scale. The primary component for a balanced and objective mitigation of the impact of these earthquakes is the correct forecast of where such kind of events may occur in the future. To date, there is a wide range of opinions about where mega-thrust earthquakes can occur. Here, we aim at presenting some detailed statistical analysis of a database of worldwide interplate earthquakes occurring at current subduction zones. The database has been recently published in the framework of the EURYI Project 'Convergent margins and seismogenesis: defining the risk of great earthquakes by using statistical data and modelling', and it provides a unique opportunity to explore in detail the seismogenic process in subducting lithosphere. In particular, the statistical analysis of this database allows us to explore many interesting scientific issues such as the existence of different frequency-magnitude distributions across the trenches, the quantitative characterization of subduction zones that are able to produce more likely mega-thrust earthquakes, the prominent features that characterize converging boundaries with different seismic activity and so on. Besides the scientific importance, such issues may lead to improve our mega-thrust earthquake forecasting capability.

  1. Uneven Magnitude of Disparities in Cancer Risks from Air Toxics

    PubMed Central

    James, Wesley; Jia, Chunrong; Kedia, Satish

    2012-01-01

    This study examines race- and income-based disparities in cancer risks from air toxics in Cancer Alley, LA, USA. Risk estimates were obtained from the 2005 National Air Toxics Assessment and socioeconomic and race data from the 2005 American Community Survey, both at the census tract level. Disparities were assessed using spatially weighted ordinary least squares (OLS) regression and quantile regression (QR) for five major air toxics, each with cancer risk greater than 10−6. Spatial OLS results showed that disparities in cancer risks were significant: People in low-income tracts bore a cumulative risk 12% more than those in high-income tracts (p < 0.05), and those in black-dominant areas 16% more than in white-dominant areas (p < 0.01). Formaldehyde and benzene were the two largest contributors to the disparities. Contributions from emission sources to disparities varied by compound. Spatial QR analyses showed that magnitude of disparity became larger at the high end of exposure range, indicating worsened disparity in the poorest and most highly concentrated black areas. Cancer risk of air toxics not only disproportionately affects socioeconomically disadvantaged and racial minority communities, but there is a gradient effect within these groups with poorer and higher minority concentrated segments being more affected than their counterparts. Risk reduction strategies should target emission sources, risk driver chemicals, and especially the disadvantaged neighborhoods. PMID:23208297

  2. Magnitude of Head Impact Exposures in Individual Collegiate Football Players

    PubMed Central

    Wilcox, Bethany J.; Machan, Jason T.; McAllister, Thomas W.; Duhaime, Ann-Christine; Duma, Stefan M.; Rowson, Steven; Beckwith, Jonathan G.; Chu, Jeffrey J.; Greenwald, Richard M.

    2013-01-01

    The purpose of this study was to quantify the severity of head impacts sustained by individual collegiate football players and to investigate differences between impacts sustained during practice and game sessions, as well as by player position and impact location. Head impacts (N = 184,358) were analyzed for 254 collegiate players at three collegiate institutions. In practice, the 50th and 95th percentile values for individual players were 20.0 g and 49.5 g for peak linear acceleration, 1187 rad/s2 and 3147 rad/s2 for peak rotational acceleration, and 13.4 and 29.9 for HITsp, respectively. Only the 95th percentile HITsp increased significantly in games compared with practices (8.4%, p= .0002). Player position and impact location were the largest factors associated with differences in head impacts. Running backs consistently sustained the greatest impact magnitudes. Peak linear accelerations were greatest for impacts to the top of the helmet, whereas rotational accelerations were greatest for impacts to the front and back. The findings of this study provide essential data for future investigations that aim to establish the correlations between head impact exposure, acute brain injury, and long-term cognitive deficits. PMID:21911854

  3. RR Lyrae: the zero point of temperature and magnitude scales.

    NASA Astrophysics Data System (ADS)

    de Santis, R.

    1996-02-01

    We find that the position in the HR diagram of the RR Lyrae variables of type ab is strictly related to properties defined in the period-amplitude plane: that is, both temperature and V magnitude of the static star are tightly correlated with blue amplitude and period. Using this pulsational approach, we show that the equilibrium temperature derived by the Baade-Wesselink (BW) method, using V and K bands, connects observational data with both pulsational and evolutionary theories in a self consistent scenario for an original helium of Y=0.23 . In contrast, we wholly confirm the inconsistency between temperature and luminosity level as derived by the BW procedure with the luminosity being wrong. We use the pulsational properties to compare the distance modulus derived by RRab variables with that obtained by the isochrone fitting procedure for a sample of galactic globular clusters (GGCs). We find a convergence to within about 0.1mag of uncertainty: in turn, this means that ages derived by both the {DELTA}V(ZAHB-TO) and the {DELTA}(B-V) methods agree to within approximately 2Gyr. Finally, we point out the following: a) the metal poor GGCs M92, M68 and M15 appear coeval (20Gyr old); b) an age spread of =~6Gyr is found in our sample of clusters.

  4. Atg17 regulates the magnitude of the autophagic response.

    PubMed

    Cheong, Heesun; Yorimitsu, Tomohiro; Reggiori, Fulvio; Legakis, Julie E; Wang, Chao-Wen; Klionsky, Daniel J

    2005-07-01

    Autophagy is a catabolic process used by eukaryotic cells for the degradation and recycling of cytosolic proteins and excess or defective organelles. In yeast, autophagy is primarily a response to nutrient limitation, whereas in higher eukaryotes it also plays a role in developmental processes. Due to its essentially unlimited degradative capacity, it is critical that regulatory mechanisms are in place to modulate the timing and magnitude of the autophagic response. One set of proteins that seems to function in this regard includes a complex that contains the Atg1 kinase. Aside from Atg1, the proteins in this complex participate primarily in either nonspecific autophagy or specific types of autophagy, including the cytoplasm to vacuole targeting pathway, which operates under vegetative growth conditions, and peroxisome degradation. Accordingly, these proteins are prime candidates for factors that regulate the conversion between these pathways, including the change in size of the sequestering vesicle, the most obvious morphological difference. The atg17delta mutant forms a reduced number of small autophagosomes. As a result, it is defective in peroxisome degradation and is partially defective for autophagy. Atg17 interacts with both Atg1 and Atg13, via two coiled-coil domains, and these interactions facilitate its inclusion in the Atg1 complex.

  5. Ultrasound Evaluation of the Magnitude of Pneumothorax: A New Concept

    NASA Technical Reports Server (NTRS)

    Sargsyan, Ashot E.; Nicolaou, S.; Kirkpatrick, A. W.; Hamilton, D. R.; Campbell, M. R,; Billica, R. D.; Dawson, D. L.; Williams, D. R.; Dulchavsky, S. A.

    2000-01-01

    Pneumothorax is commonly seen in trauma patients; the diagnosis is usually confirmed by radiography. Use of ultrasound for this purpose, in environments such as space flight and remote terrestrial areas where radiographic capabilities are absent, is being investigated by NASA. In this study, the ability of ultrasound to assess the magnitude of pneumothorax in a porcine model was evaluated. Sonography was performed on anesthetized pigs (avg. wt. 50 kg) in both ground-based laboratory (n = 5) and micro gravity conditions (0 g) aboard the KC-135 aircraft during parabolic flight (n = 4). Aliquots of air (50-1 OOcc) were introduced into the chest through a catheter to simulate pneumothorax. Results were video-recorded and digitized for later interpretation by radiologists. Several distinct sonographic patterns of partial lung sliding were noted, including the combination of a sliding zone with a still zone, and a "segmented" sliding zone. These "partial lung sliding" patterns exclude massive pneumothorax manifested by a complete separation of the lung from the parietal pleura. In 0 g, the sonographic picture was more diverse; 1 g differences between posterior and anterior aspects were diminished. CONCLUSIONS: Modest pneumothorax can be inferred by the ultrasound sign of "partial lung sliding". This finding, which increases the negative predictive value of thoracic ultrasound, may be attributed to intermittent pleural contact, small air spaces, or alterations in pleural lubricant. Further studies of these phenomena are warranted.

  6. Size matters: Perceived depth magnitude varies with stimulus height.

    PubMed

    Tsirlin, Inna; Wilcox, Laurie M; Allison, Robert S

    2016-06-01

    Both the upper and lower disparity limits for stereopsis vary with the size of the targets. Recently, Tsirlin, Wilcox, and Allison (2012) suggested that perceived depth magnitude from stereopsis might also depend on the vertical extent of a stimulus. To test this hypothesis we compared apparent depth in small discs to depth in long bars with equivalent width and disparity. We used three estimation techniques: a virtual ruler, a touch-sensor (for haptic estimates) and a disparity probe. We found that depth estimates were significantly larger for the bar stimuli than for the disc stimuli for all methods of estimation and different configurations. In a second experiment, we measured perceived depth as a function of the height of the bar and the radius of the disc. Perceived depth increased with increasing bar height and disc radius suggesting that disparity is integrated along the vertical edges. We discuss size-disparity correlation and inter-neural excitatory connections as potential mechanisms that could account for these results.

  7. Metal-Organic Coordination Number Determined Charge Transfer Magnitude

    NASA Astrophysics Data System (ADS)

    Yang, Hung-Hsiang; Chu, Yu-Hsun; Lu, Chun-I.; Yang, Tsung-Han; Yang, Kai-Jheng; Kaun, Chao-Cheng; Hoffmann, Germar; Lin, Minn-Tsong

    2014-03-01

    By the appropriate choice of head groups and molecular ligands, various metal-organic coordination geometries can be engineered. Such metal-organic structures provide different chemical environments for molecules and give us templates to study the charge redistribution within the metal-organic interface. We created various metal-organic bonding environment by growing self-assembly nanostructures of Fe-PTCDA (3,4,9,10-perylene tetracarboxylic dianhydride) chains and networks on a Au(111) surface. Bonding environment dependent frontier molecular orbital energies are acquired by low temperature scanning tunneling microscopy and scanning tunneling spectroscopy. By comparing the frontier energies with the molecular coordination environments, we conclude that the specific coordination affects the magnitude of charge transfer onto each PTCDA in the Fe-PTCDA hybridization system. H.-H. Yang, Y.-H. Chu, C.-I Lu, T.-H. Yang, K.-J. Yang, C.-C. Kaun, G. Hoffmann, and M.-T. Lin, ACS Nano 7, 2814 (2013).

  8. FPGA-specific decimal sign-magnitude addition and subtraction

    NASA Astrophysics Data System (ADS)

    Vázquez, Martín; Todorovich, Elías

    2016-07-01

    The interest in sign-magnitude (SM) representation in decimal numbers lies in the IEEE 754-2008 standard, where the significand in floating-point numbers is coded as SM. However, software implementations do not meet performance constraints in some applications and more development is required in programmable logic, a key technology for hardware acceleration. Thus, in this work, two strategies for SM decimal adder/subtractors are studied and six new Field Programmable Gate Array (FPGA)-specific circuits are derived from these strategies. The first strategy is based on ten's complement (C10) adder/subtractors and the second one is based on parallel computation of an unsigned adder and an unsigned subtractor. Four of these alternative circuits are useful for at least one area-time-trade-off and specific operand size. For example, the fastest SM adder/subtractor for operand sizes of 7 and 16 decimal digits is based on the second proposed strategy with delays of 3.43 and 4.33 ns, respectively, but the fastest circuit for 34-digit operands is one of the three specific implementations based on C10 adder/subtractors with a delay of 4.65 ns.

  9. HDF Limiting Magnitude/Resolution Extension and Object Variability Search

    NASA Astrophysics Data System (ADS)

    Gilliland, Ronald

    1997-07-01

    Further WFPC2 observations of the HDF were obtained 23-26 Dec. '97 as part of my Cycle 6 program: ``A Search for Supernovae at High Z in the HDF." Science particular to the SNe search will be funded from the GO-6473 grant; here I propose to: {1} Release deeper F814W and F300W images. F814W exposures over the non-bright portions of 18 orbits when added to the existing HDF set will boost total exposure time by 51 magnitude better by 0.23 mag, with other improvements this rises to 0.35 mag}, and F300W during bright time by 18 {2} Extend code {and release} development for a full dithered image set combination that does a better job of preserving clean point spread functions than the existing HDF {version two} working group release, with an additional minor gain in background noise level. This is important in particular for detection of faint point sources and for maintaining PSF stability necessary to allow resolution enhancement experiments through deconvolution. {3} Perform exploratory searches for object variability on time scales from 1 hour to 10 days in the existing HDF data. My approach to the data reductions is unique in maintaining an easy to analyze auxiliary set of single frames for variability studies.

  10. Physics-based estimates of maximum magnitude of induced earthquakes

    NASA Astrophysics Data System (ADS)

    Ampuero, Jean-Paul; Galis, Martin; Mai, P. Martin

    2016-04-01

    In this study, we present new findings when integrating earthquake physics and rupture dynamics into estimates of maximum magnitude of induced seismicity (Mmax). Existing empirical relations for Mmax lack a physics-based relation between earthquake size and the characteristics of the triggering stress perturbation. To fill this gap, we extend our recent work on the nucleation and arrest of dynamic ruptures derived from fracture mechanics theory. There, we derived theoretical relations between the area and overstress of overstressed asperity and the ability of ruptures to either stop spontaneously (sub-critical ruptures) or runaway (super-critical ruptures). These relations were verified by comparison with simulation and laboratory results, namely 3D dynamic rupture simulations on faults governed by slip-weakening friction, and laboratory experiments of frictional sliding nucleated by localized stresses. Here, we apply and extend these results to situations that are representative for the induced seismicity environment. We present physics-based predictions of Mmax on a fault intersecting cylindrical reservoir. We investigate Mmax dependence on pore-pressure variations (by varying reservoir parameters), frictional parameters and stress conditions of the fault. We also derive Mmax as a function of injected volume. Our approach provides results that are consistent with observations but suggests different scaling with injected volume than that of empirical relation by McGarr, 2014.

  11. Magnitude of Interfractional Vaginal Cuff Movement: Implications for External Irradiation

    SciTech Connect

    Ma, Daniel J.; Michaletz-Lorenz, Martha; Goddu, S. Murty; Grigsby, Perry W.

    2012-03-15

    Purpose: To quantify the extent of interfractional vaginal cuff movement in patients receiving postoperative irradiation for cervical or endometrial cancer in the absence of bowel/bladder instruction. Methods and Materials: Eleven consecutive patients with cervical or endometrial cancer underwent placement of three gold seed fiducial markers in the vaginal cuff apex as part of standard of care before simulation. Patients subsequently underwent external irradiation and brachytherapy treatment based on institutional guidelines. Daily megavoltage CT imaging was performed during each external radiation treatment fraction. The daily positions of the vaginal apex fiducial markers were subsequently compared with the original position of the fiducial markers on the simulation CT. Composite dose-volume histograms were also created by summing daily target positions. Results: The average ({+-} standard deviation) vaginal cuff movement throughout daily pelvic external radiotherapy when referenced to the simulation position was 16.2 {+-} 8.3 mm. The maximum vaginal cuff movement for any patient during treatment was 34.5 mm. In the axial plane the mean vaginal cuff movement was 12.9 {+-} 6.7 mm. The maximum vaginal cuff axial movement was 30.7 mm. In the craniocaudal axis the mean movement was 10.3 {+-} 7.6 mm, with a maximum movement of 27.0 mm. Probability of cuff excursion outside of the clinical target volume steadily dropped as margin size increased (53%, 26%, 4.2%, and 1.4% for 1.0, 1.5, 2.0, and 2.5 cm, respectively.) However, rectal and bladder doses steadily increased with larger margin sizes. Conclusions: The magnitude of vaginal cuff movement is highly patient specific and can impact target coverage in patients without bowel/bladder instructions at simulation. The use of vaginal cuff fiducials can help identify patients at risk for target volume excursion.

  12. Magnitude and Prevention of College Drinking and Related Problems

    PubMed Central

    Hingson, Ralph W.

    2010-01-01

    In 2002, the National Institute on Alcohol Abuse and Alcoholism (NIAAA) issued a report entitled A Call to Action: Changing the Culture of Drinking at U.S. Colleges. Data on the magnitude of college drinking problems in 1998 to 1999 were reported. From 1999 to 2005, the proportion of college students aged 18–24 who drank five or more drinks on a single occasion in the past month increased from 41.7 percent to 45.2 percent. The proportion who drove under the influence of alcohol increased from 26.1 percent to 29.2 percent. Higher percentages of 21- to 24-year-olds engaged in those behaviors than 18- to 20-year-olds, and between 1999 and 2005 the percentage increased among 21- to 24-year-olds but not among those aged 18–20. From 1998 to 2005, unintentional alcohol-related injury deaths increased 3 percent (from 1,442 to 1,825) per 100,000 college students aged 18–24. Alcohol misuse by college students often harms other people through traffic crashes and sexual/other assaults. Research regarding ways to reduce college drinking problems has shown that individual-oriented interventions, particularly screening and brief motivational counseling interventions, social norms interventions, environmental policy changes such as the minimum legal drinking age of 21 and drinking-and-driving laws, and comprehensive college–community programs, can reduce college drinking and related morbidity and mortality. There is a growing need for colleges and surrounding communities to implement interventions shown through research to reduce alcohol misuse among college-aged people. PMID:23579935

  13. Magnitude of food overabundance affects expression of daily torpor.

    PubMed

    Eto, Takeshi; Hayashi, Rintaroh; Okubo, Yoshinobu; Kashimura, Atsushi; Koshimoto, Chihiro; Sakamoto, Shinsuke H; Morita, Tetsuo

    2015-02-01

    Many small mammal species use torpor as a strategy for reducing energy expenditure in winter. Some rodent hibernators also hoard food to provide reserves of energy, and individuals with large hoards express less torpor than those with smaller reserves. These facts imply that animals can recognize levels of food availability, but where food is very plentiful, it is unclear whether torpor expression is affected by temporal changes in the extent of food overabundance. Moreover, the relationship between daily torpor and excess food availability has not been clearly established. The large Japanese field mouse Apodemus speciosus caches food for use as a winter energy resource and exhibits daily torpor under artificial winter conditions. The present study examined whether individuals exposed to different magnitudes of overabundant food exhibited differences in expression of daily torpor, and secondly whether torpor expression varied in response to changes in the overall quantity of overabundant food. It was observed that while absolute quantities of overabundant food did not appear to affect daily torpor expression, the mice did respond to changes in food availability, even when food remained overabundant. This suggests that the mice respond to fluctuations in food availability, even where these changes do not place any constraint on energy budgets. Thus recognition of changing food availability cannot be a purely physiological response to shortage or plenty, and may contribute to predictions of future energy availability. The expression of torpor was inhibited in response to increasing food availability, and the mice used shallower torpor when food availability increased to superabundance. These findings suggest that daily torpor may be regulated not only physiologically in response to energy constraints but also psychologically, via recognition of food availability.

  14. Great earthquakes of variable magnitude at the Cascadia subduction zone

    USGS Publications Warehouse

    Nelson, A.R.; Kelsey, H.M.; Witter, R.C.

    2006-01-01

    Comparison of histories of great earthquakes and accompanying tsunamis at eight coastal sites suggests plate-boundary ruptures of varying length, implying great earthquakes of variable magnitude at the Cascadia subduction zone. Inference of rupture length relies on degree of overlap on radiocarbon age ranges for earthquakes and tsunamis, and relative amounts of coseismic subsidence and heights of tsunamis. Written records of a tsunami in Japan provide the most conclusive evidence for rupture of much of the plate boundary during the earthquake of 26 January 1700. Cascadia stratigraphic evidence dating from about 1600??cal yr B.P., similar to that for the 1700 earthquake, implies a similarly long rupture with substantial subsidence and a high tsunami. Correlations are consistent with other long ruptures about 1350??cal yr B.P., 2500??cal yr B.P., 3400??cal yr B.P., 3800??cal yr B.P., 4400??cal yr B.P., and 4900??cal yr B.P. A rupture about 700-1100??cal yr B.P. was limited to the northern and central parts of the subduction zone, and a northern rupture about 2900??cal yr B.P. may have been similarly limited. Times of probable short ruptures in southern Cascadia include about 1100??cal yr B.P., 1700??cal yr B.P., 3200??cal yr B.P., 4200??cal yr B.P., 4600??cal yr B.P., and 4700??cal yr B.P. Rupture patterns suggest that the plate boundary in northern Cascadia usually breaks in long ruptures during the greatest earthquakes. Ruptures in southernmost Cascadia vary in length and recurrence intervals more than ruptures in northern Cascadia.

  15. Order of magnitude reduction of fluoroscopic x-ray dose

    NASA Astrophysics Data System (ADS)

    Bal, Abhinav; Robert, Normand; Machan, Lindsay; Deutsch, Meir; Kisselgoff, David; Babyn, Paul; Rowlands, John A.

    2012-03-01

    The role of fluoroscopic imaging is critical for diagnostic and image guided therapy. However, fluoroscopic imaging can require significant radiation leading to increased cancer risk and non-stochastic effects such as radiation burns. Our purpose is to reduce the exposure and dose to the patient by an order of magnitude in these procedures by use of the region of interest method. Method and Materials: Region of interest fluoroscopy (ROIF) uses a partial attenuator. The central region of the image has full exposure while the image periphery, there to provide context only, has a reduced exposure rate. ROIF using a static partial attenuator has been shown in our previous studies to reduce the dose area product (DAP) to the patient by at least 2.5 times. Significantly greater reductions in DAP would require improvements in flat panel detectors performance at low x-ray exposures or a different x-ray attenuation strategy. Thus we have investigated a second, dynamic, approach. We have constructed an x-ray shutter system allowing a normal x-ray exposure in the region of interest while reducing the number of x-ray exposures in the periphery through the rapid introduction, positioning and removal of an x-ray attenuating shutter to block radiation only for selected frames. This dynamic approach eliminates the DQE(0) loss associated with the use of static partial attenuator applied to every frame thus permitting a greater reduction in DAP. Results: We have compared the two methods by modeling and determined their fundamental limits.

  16. Refining the Magnitude of the Shallow Slip Deficit

    NASA Astrophysics Data System (ADS)

    Xu, X.; Tong, X.; Sandwell, D. T.; Milliner, C. W. D.

    2014-12-01

    Geodetic inversions for slip versus depth for several major (Mw > 7) strike-slip earthquakes (e.g. 1992 Landers, 1999 Hector Mine, 2010 El_Mayor-Cucapah) show a 10% to 40% reduction in slip near surface (depth < 2 km) compared to the slip at deeper depths (5 to 8 km). This has been called the shallow slip deficit (SSD). The large magnitude of this deficit has been an enigma since it cannot be explained by shallow creep during the interseismic period or by triggered slip from nearby earthquakes. One potential explanation for the SSD is that the previous geodetic inversions used incomplete data that do not go close to fault so the shallow portions of the slip models were poorly resolved and generally underestimated. In this study we improve the geodetic inversion, especially at shallow depth by: 1) refining the InSAR processing with non-boxcar phase filtering, model-dependent range corrections, more complete phase unwrapping by SNAPHU using a correlation mask and allowing a phase discontinuity along the rupture; 2) including near-fault offset data from optical imagery and SAR azimuth offsets; 3) using more detailed fault geometry; 4) and using additional campaign GPS data. With these improved observations, the slip inversion has significantly increased resolution at shallow depth. For the Landers rupture the SSD is reduced from 45% to 16%. Similarly for the Hector Mine rupture the SSD is reduced from 15% to 5%. We are assembling all the relevant co-seismic data for the El Major-Cucapah earthquake and will report the inversion result with its SSD at the meeting.

  17. Magnitude and Carbon Consequences of Forest Management in North America

    NASA Astrophysics Data System (ADS)

    Masek, J.; Kurz, W.; de Jong, B. H.

    2009-12-01

    The carbon balance of forests depends on the type, frequency and severity of recent disturbances (carbon source) and the rate of recovery from past disturbance (carbon sink). Harvest and land cover conversion represent significant forest disturbance agents over much of North America. For example, pine forests in the southeastern US are typically harvested at ~20 year intervals, and may occupy about half the regional landscape, resulting in regional landscape turnover rates of 2-3% per year. Inventory data are the primary source for quantifying information on harvest and conversion in the U.S., Mexico, and Canada. Recent inventory data from these countries indicate timber production of 424 million cu m, 163 million cu m, and 7 million cu m, respectively, with significant year-to-year variability associated with wood products demand and timber price. Areas affected by harvest activity vary as well, with 3.97 Mha (million hectares) and 1.04 Mha affected by harvest in the US and Canada, respectively. Forest cover conversion (deforestation) is thought to be relatively minor in the US and Canada, but recent estimates suggest that forest and woodland cover in Mexico declined by 300-500 Kha/yr during the 1990’s. Recently, satellite remote sensing data products on forest change have been generated that complement the traditional inventory approach. These products are particularly useful for “wall-to-wall” estimates of forest conversion and tracking small disturbances. The type and severity of disturbance cannot be easily determined using satellite observations, however, and therefore some care must be taken to reconcile these products with ground-based data. In this talk we review available resources for characterizing “carbon relevant” information on the magnitude (area, type of activity) of forest management in North America, and attempt a first-order comparison between remote sensing and inventory estimates. We also discuss strategies that might be employed to

  18. Variation of SEP event occurrence with heliospheric magnetic field magnitudes

    NASA Astrophysics Data System (ADS)

    Kahler, S. W.

    2009-05-01

    Recent work based on nitrate abundances in polar ice cores has shown that large fluence solar energetic (E>30MeV) particle (LSEP) events during the spacecraft era of observations (1960-present) are diminished in comparison with those of some preceding eras detected in the ice cores dating back to 1561. McCracken et al. [McCracken, K.G., Dreschhoff, G.A.M., Smart, D.F., Shea, M.A. A study of the frequency of occurrence of large-fluence solar proton events and the strength of the interplanetary magnetic field, Sol. Phys., 224, 359-372, 2004] have reported an inverse correlation between LSEP events and the magnitudes of the associated reconstructed heliospheric magnetic fields (HMF). A physical working model by McCracken [McCracken, K.G. Changes in the cosmic ray and heliomagnetic components of space climate, 1428-2005, including the variable occurrence of solar energetic particle events, Adv. Space Res., 40, 1070-1077, 2007a; McCracken, K.G. High frequency of occurrence of large solar energetic particle events prior to 1958 and a possible repetition in the near future, Space Weather, 5, S07004, 2007b] is that the lower HMF and coronal magnetic field B imply that fast coronal mass ejections (CMEs) produce shocks with enhanced Alfvenic Mach numbers MA and higher compression ratios r, leading to shock production of more numerous and energetic LSEP events. From a possible decline of the HMF over the next several solar cycles he has urged a watch for a return to the environment of high-frequency, high-fluence LSEP events preceding the current spacecraft era. His LSEP event watch involves three independent questions about (1) the physical model, (2) the prediction of decreasing solar-cycle sunspot numbers and heliomagnetic fields, and (3) the inferred anti-correlation between LSEP events and HMFs. Here we discuss observational evidence bearing on the last question and find little support for the claimed LSEP-HMF anticorrelation.

  19. Floods in the United States: Magnitude and Frequency

    USGS Publications Warehouse

    Jarvis, Clarence S.; ,

    1936-01-01

    FOREWORD 'The ideal river, which would have a uniform flow, does not exist in nature.' (Mississippi Valley Committee Report, 2d ed., p. 3, 1934.) From time immemorial floods have transformed beneficent river waters into a menace to humanity. ManTs progress toward economic stability has been repeatedly halted or even thrown backward by the interruption of his efforts to make effective use of rivers and of valley lands. This handicap is not imposed by the destructiven&ss of large rivers alone, or of rivers in widely separated areas, for there are few if any streams, brooks, or rivulets that are not subject to flows beyond their channel capacities. Yet, though man for ages has suffered seriously from recurring floods, he has not been deterred from continuing to extend his activities in areas that are virtually foredoomed to flood damage. Today in the United states serious floods may occur in any section in any year, and even, in some regions, several times a year. Many of these floods leave behind them the tragedy of death and disease and of property irreparably damaged. The aggregate direct property damage caused by floods in this country has been estimated roughly to average $35,000,000 a year. In addition there are serious indirect and intangible losses of great but not precisely calculable magnitude. The persistent recurrence of flood damages in our country, and, indeed, their tendency to increase, have given birth to the mistaken notion that floods are increasing in size and frequency. The rising damage totals are not attributable to greater or more frequent floods, however; rather they are the result of increasing occupation of river banks and river valleys by cities, towns, industrial plants, bridges, railroads, and highways and the increasing use of rivers as a source of water supplies for municipalities and industries and for power, irrigation, navigation, and recreation. Safety of life and reduction of both direct and indirect losses from floods may be

  20. Aplicación del Teorema de Nekhorochev para tiempos de estabilidad en Mecánica Celeste

    NASA Astrophysics Data System (ADS)

    Miloni, O.; Núñez, J.; Brunini, A.

    En Mecánica Celeste, uno de los problemas centrales consiste en la determinación de los tiempos de estabilidad. El teorema de Nekhorochev proporciona un método para dicho estudio, para un sistema determinado por un hamiltoniano descripto en las variables acción-ángulo. El trabajo consiste en la acotación tanto del potencial perturbador y de la matriz hessiana del hamiltoniano integrable para determinar luego el tiempo de estabilidad de dicho sistema, donde por estabilidad se entiende la separación en norma infinito en el espacio de las acciones.

  1. The Effects of Numerical Magnitude, Size, and Color Saturation on Perceived Interval Duration

    ERIC Educational Resources Information Center

    Alards-Tomalin, Doug; Leboe-McGowan, Jason P.; Shaw, Joshua D. M.; Leboe-McGowan, Launa C.

    2014-01-01

    The relative magnitude (or intensity) of an event can have direct implications on timing estimation. Previous studies have found that greater magnitude stimuli are often reported as longer in duration than lesser magnitudes, including Arabic digits (Xuan, Zhang, He, & Chen, 2007). One explanation for these findings is that different…

  2. SNARC-like Congruency Based on Number Magnitude and Response Duration

    ERIC Educational Resources Information Center

    Kiesel, Andrea; Vierck, Esther

    2009-01-01

    Recent findings demonstrated that number magnitude affects the perception of display time (B. Xuan, D. Zhang, S. He, & X. Chen, 2007). Participants made fewer errors when display time (e.g., short) and magnitude (e.g., small) matched, suggesting an influence of magnitude on time perception. With the present experiment, the authors aimed to extend…

  3. The Effects of Reinforcement Magnitude on Skill Acquisition for Children with Autism

    ERIC Educational Resources Information Center

    Paden, Amber R.; Kodak, Tiffany

    2015-01-01

    We examined the effects of reinforcement magnitude on skill acquisition during discrete-trial training. After conducting a magnitude preference assessment, we compared acquisition during conditions with large and small magnitudes of edible reinforcement to a praise-only condition. Although all participants showed a preference for the…

  4. Model parameter estimation bias induced by earthquake magnitude cut-off

    NASA Astrophysics Data System (ADS)

    Harte, D. S.

    2016-02-01

    We evaluate the bias in parameter estimates of the ETAS model. We show that when a simulated catalogue is magnitude-truncated there is considerable bias, whereas when it is not truncated there is no discernible bias. We also discuss two further implied assumptions in the ETAS and other self-exciting models. First, that the triggering boundary magnitude is equivalent to the catalogue completeness magnitude. Secondly, the assumption in the Gutenberg-Richter relationship that numbers of events increase exponentially as magnitude decreases. These two assumptions are confounded with the magnitude truncation effect. We discuss the effect of these problems on analyses of real earthquake catalogues.

  5. The association between symbolic and nonsymbolic numerical magnitude processing and mental versus algorithmic subtraction in adults.

    PubMed

    Linsen, Sarah; Torbeyns, Joke; Verschaffel, Lieven; Reynvoet, Bert; De Smedt, Bert

    2016-03-01

    There are two well-known computation methods for solving multi-digit subtraction items, namely mental and algorithmic computation. It has been contended that mental and algorithmic computation differentially rely on numerical magnitude processing, an assumption that has already been examined in children, but not yet in adults. Therefore, in this study, we examined how numerical magnitude processing was associated with mental and algorithmic computation, and whether this association with numerical magnitude processing was different for mental versus algorithmic computation. We also investigated whether the association between numerical magnitude processing and mental and algorithmic computation differed for measures of symbolic versus nonsymbolic numerical magnitude processing. Results showed that symbolic, and not nonsymbolic, numerical magnitude processing was associated with mental computation, but not with algorithmic computation. Additional analyses showed, however, that the size of this association with symbolic numerical magnitude processing was not significantly different for mental and algorithmic computation. We also tried to further clarify the association between numerical magnitude processing and complex calculation by also including relevant arithmetical subskills, i.e. arithmetic facts, needed for complex calculation that are also known to be dependent on numerical magnitude processing. Results showed that the associations between symbolic numerical magnitude processing and mental and algorithmic computation were fully explained by individual differences in elementary arithmetic fact knowledge. PMID:26914586

  6. Improved rapid magnitude estimation for a community-based, low-cost MEMS accelerometer network

    USGS Publications Warehouse

    Chung, Angela I.; Cochran, Elizabeth S.; Kaiser, Anna E.; Christensen, Carl M.; Yildirim, Battalgazi; Lawrence, Jesse F.

    2015-01-01

    Immediately following the Mw 7.2 Darfield, New Zealand, earthquake, over 180 Quake‐Catcher Network (QCN) low‐cost micro‐electro‐mechanical systems accelerometers were deployed in the Canterbury region. Using data recorded by this dense network from 2010 to 2013, we significantly improved the QCN rapid magnitude estimation relationship. The previous scaling relationship (Lawrence et al., 2014) did not accurately estimate the magnitudes of nearby (<35  km) events. The new scaling relationship estimates earthquake magnitudes within 1 magnitude unit of the GNS Science GeoNet earthquake catalog magnitudes for 99% of the events tested, within 0.5 magnitude units for 90% of the events, and within 0.25 magnitude units for 57% of the events. These magnitudes are reliably estimated within 3 s of the initial trigger recorded on at least seven stations. In this report, we present the methods used to calculate a new scaling relationship and demonstrate the accuracy of the revised magnitude estimates using a program that is able to retrospectively estimate event magnitudes using archived data.

  7. EVALUATION REINFORCER MAGNITUDE AND RATE DEPENDENCY OF RESISTANCE TO CHANGE MECHANIMS

    PubMed Central

    Pinkston, Jonathan W.; Ginsburg, Brett C.; Lamb, R. J.

    2015-01-01

    In many circumstances, reinforcer magnitude appears to modulate the rate-dependent effects of drugs, such that when schedules arrange for relatively larger reinforcer magnitude, rate dependency is attenuated compared to behavior maintained by smaller magnitudes. The current literature on resistance to change suggests that increased reinforcer density strengthens operant behavior, and such strengthening effects appear to extend to the temporal control of behavior. As rate dependency may be understood as a loss of temporal control, the effects of reinforcer magnitude on rate dependency may be due to increased resistance to disruption of temporally controlled behavior. In the present experiments, pigeons earned different magnitudes of grain during signaled components of a multiple fixed-interval schedule. Three drugs, clonidine, haloperidol, and morphine, were examined: all three decreased overall rates of key pecking; however, only the effects of clonidine were attenuated as reinforcer magnitude increased. An analysis of within-interval performance found rate-dependent effects for clonidine and morphine, but those effects were not modulated by reinforcer magnitude. Additionally, we included prefeeding and extinction conditions, standard tests used to measure resistance to change. In general, rate-decreasing effects of prefeeding and extinction were attenuated by increasing reinforcer magnitudes. Rate-dependent analyses of prefeeding showed rate-dependency following those tests, but in no case were these effects modulated by reinforcer magnitude. The results suggest a resistance-to-change interpretation of the effects of reinforcer magnitude on rate dependency is not viable. PMID:25115595

  8. The impact of emotion on the perception of graded magnitudes of respiratory resistive loads.

    PubMed

    Tsai, Hsiu-Wen; Chan, Pei-Ying; von Leupoldt, Andreas; Davenport, Paul W

    2013-04-01

    Emotional state can modulate the perception of respiratory loads but the range of respiratory load magnitudes affected by emotional state is unknown. We hypothesized that viewing pleasant, neutral and unpleasant affective pictures would modulate the perception of respiratory loads of different load magnitudes. Twenty-four healthy adults participated in the study. Five inspiratory resistive loads of increasing magnitude (5, 10, 15, 20, 45 cm H(2)O/L/s) were repeatedly presented for one inspiration while participants viewed pleasant, neutral and unpleasant affective picture series. Participants rated how difficult it was to breathe against the load immediately after each presentation. Only at the lowest load, magnitude estimation ratings were greater when subjects viewed the unpleasant series compared to the neutral and pleasant series. These results suggest that negative emotional state increases the sense of respiratory effort for single presentations of a low magnitude resistive load but high magnitude loads are not further modulated by emotional state.

  9. Probability of a given-magnitude earthquake induced by a fluid injection

    NASA Astrophysics Data System (ADS)

    Shapiro, S. A.; Dinske, C.; Kummerow, J.

    2007-11-01

    Fluid injections in geothermic and hydrocarbon reservoirs induce small earthquakes (-3 < M < 2). Occasionally, however, earthquakes with larger magnitudes (M ~ 4) occur. We investigate magnitude distributions and show that for a constant injection pressure the probability to induce an earthquake with a magnitude larger than a given value increases with injection time corresponding to a bi-logarithmical law with a proportionality coefficient close to one. We find that the process of pressure diffusion in a poroelastic medium with randomly distributed sub-critical cracks obeying a Gutenberg-Richter relation well explains our observations. The magnitude distribution is mainly inherited from the statistics of pre-existing fracture systems. The number of earthquakes greater than a given magnitude also increases with the strength of the injection source and the tectonic activity of the injection site. Our formulation provides a way to estimate expected magnitudes of induced earthquakes. It can be used to avoid significant earthquakes by correspondingly planning fluid injections.

  10. Epistemic uncertainty in the location and magnitude of earthquakes in Italy from Macroseismic data

    USGS Publications Warehouse

    Bakun, W.H.; Gomez, Capera A.; Stucchi, M.

    2011-01-01

    Three independent techniques (Bakun and Wentworth, 1997; Boxer from Gasperini et al., 1999; and Macroseismic Estimation of Earthquake Parameters [MEEP; see Data and Resources section, deliverable D3] from R.M.W. Musson and M.J. Jimenez) have been proposed for estimating an earthquake location and magnitude from intensity data alone. The locations and magnitudes obtained for a given set of intensity data are almost always different, and no one technique is consistently best at matching instrumental locations and magnitudes of recent well-recorded earthquakes in Italy. Rather than attempting to select one of the three solutions as best, we use all three techniques to estimate the location and the magnitude and the epistemic uncertainties among them. The estimates are calculated using bootstrap resampled data sets with Monte Carlo sampling of a decision tree. The decision-tree branch weights are based on goodness-of-fit measures of location and magnitude for recent earthquakes. The location estimates are based on the spatial distribution of locations calculated from the bootstrap resampled data. The preferred source location is the locus of the maximum bootstrap location spatial density. The location uncertainty is obtained from contours of the bootstrap spatial density: 68% of the bootstrap locations are within the 68% confidence region, and so on. For large earthquakes, our preferred location is not associated with the epicenter but with a location on the extended rupture surface. For small earthquakes, the epicenters are generally consistent with the location uncertainties inferred from the intensity data if an epicenter inaccuracy of 2-3 km is allowed. The preferred magnitude is the median of the distribution of bootstrap magnitudes. As with location uncertainties, the uncertainties in magnitude are obtained from the distribution of bootstrap magnitudes: the bounds of the 68% uncertainty range enclose 68% of the bootstrap magnitudes, and so on. The instrumental

  11. Design of recursive digital filters having specified phase and magnitude characteristics

    NASA Technical Reports Server (NTRS)

    King, R. E.; Condon, G. W.

    1972-01-01

    A method for a computer-aided design of a class of optimum filters, having specifications in the frequency domain of both magnitude and phase, is described. The method, an extension to the work of Steiglitz, uses the Fletcher-Powell algorithm to minimize a weighted squared magnitude and phase criterion. Results using the algorithm for the design of filters having specified phase as well as specified magnitude and phase compromise are presented.

  12. An analysis of Almagest magnitudes for the study of stellar evolution.

    NASA Astrophysics Data System (ADS)

    Hearnshaw, J. B.

    Visual magnitude data in Ptolemy's Almagest are analysed by comparing them with modern photoelectric magnitudes on the Pogson scale, after taking extinction into account. The results show that a linear relationship exists between Almagest and Pogson scales, contrary to the findings of earlier authors, with one Almagest magnitude being equal to about 1.36 Pogson magnitudes. This result is used to transform Almagest magnitudes to the Pogson scale. A study is made of changes in the visual magnitudes of supergiant stars in the Almagest between classical and modern times (an interval of nearly 19 centuries). No evidence is found for any secular changes in the mean brightness of these stars, contrary to the conclusion of Mayer (Observatory 104, 77 (1984)). However, it is shown that the Almagest magnitudes for stars in the Milky Way are on average 0.34 Pogson magnitudes too faint, and about half the Almagest supergiants are affected by this. Finally, some evidence is cited for the visual atmospheric extinction in classical times being significantly less than today. If this is the case, and it is not taken into account, it would mimic an apparent supergiant brightening of about 0.1 magnitudes over this time interval.

  13. The Compiled Catalogue of Photoelectric UBVR Stellar Magnitudes in the TYCHO2 System

    NASA Astrophysics Data System (ADS)

    Relke, E.; Protsyuk, Yu. I.; Andruk, V. M.

    In order to calibrate the images of astronomical photographic plates from the archive of UkrVO was created the compiled catalogue of photoelectric UBVR stellar magnitudes. It is based on: the Kornilov catalogue of 13586 WBVR stellar magnitudes (Kornilov at al., 1991), the Mermilliod catalogue of 68540 UBV stellar magnitudes (Mermilliod, 1991) and the Andruk catalogue of 1141 UBVR stellar magnitudes (Andruk at al.,1995). All original coordinates have the different epoch and equinox. We performed the cross reference of stars from these three catalogues with the Tycho2, UCAC4 and XPM catalogues and created a new photometric catalogue on the epoch and equinox of J2000.0.

  14. Effects of reinforcer magnitude and distribution on preference for work schedules.

    PubMed

    Ward-Horner, John C; Pittenger, Alexis; Pace, Gary; Fienup, Daniel M

    2014-01-01

    When the overall magnitude of reinforcement is matched between 2 alternative work schedules, some students prefer to complete all of their work for continuous access to a reinforcer (continuous work) rather than distributed access to a reinforcer while they work (discontinuous work). We evaluated a student's preference for continuous work by manipulating the overall magnitude of reinforcement associated with continuous work. Preference for continuous work persisted despite a 20% decrease in reinforcer magnitude; however, a 40% decrease in reinforcer magnitude produced a shift in preference to discontinuous work.

  15. Asymmetric Processing of Numerical and Nonnumerical Magnitudes in the Brain: An fMRI Study.

    PubMed

    Leibovich, Tali; Vogel, Stephan E; Henik, Avishai; Ansari, Daniel

    2016-01-01

    It is well established that, when comparing nonsymbolic magnitudes (e.g., dot arrays), adults can use both numerical (i.e., the number of items) and nonnumerical (density, total surface areas, etc.) magnitudes. It is less clear which of these magnitudes is more salient or processed more automatically. In this fMRI study, we used a nonsymbolic comparison task to ask if different brain areas are responsible for the automatic processing of numerical and nonnumerical magnitudes, when participants were instructed to attend to either the numerical or the nonnumerical magnitudes of the same stimuli. An interaction of task (numerical vs. nonnumerical) and congruity (congruent vs. incongruent) was found in the right TPJ. Specifically, this brain region was more strongly activated during numerical processing when the nonnumerical magnitudes were negatively correlated with numerosity (incongruent trials). In contrast, such an interference effect was not evident during nonnumerical processing when the task-irrelevant numerical magnitude was incongruent. In view of the role of the right TPJ in the control of stimulus-driven attention, we argue that these data demonstrate that the processing of nonnumerical magnitudes is more automatic than that of numerical magnitudes and that, therefore, the influence of numerical and nonnumerical variables on each other is asymmetrical. PMID:26439268

  16. The Faber-Jackson relation for early-type galaxies: dependence on the magnitude range

    NASA Astrophysics Data System (ADS)

    Nigoche-Netro, A.; Aguerri, J. A. L.; Lagos, P.; Ruelas-Mayorga, A.; Sánchez, L. J.; Machado, A.

    2010-06-01

    Aims: Previous studies have found that the coefficients and intrinsic dispersions of both the Kormendy relation and the Fundamental Plane depend on the magnitude range within which the galaxies are contained. We study whether this type of behaviour is also present for the Faber-Jackson relation. Methods: We take a sample of early-type galaxies from the Sloan Digital Sky Survey (SDSS-DR7, ~90 000 galaxies) spanning a range of approximately 7 mag in both g and r filters and analyse the behaviour of the Faber-Jackson relation parameters as functions of the magnitude range. We calculate the parameters in two ways: i) we consider the faintest (brightest) galaxies in each sample and we progressively increase the width of the magnitude interval by inclusion of the brighter (fainter) galaxies (increasing-magnitude-intervals); and ii) we consider narrow-magnitude intervals of the same width (ΔM = 1.0 mag) over the whole magnitude range available (narrow-magnitude-intervals). Results: Our main results are that: i) in both increasing and narrow-magnitude-intervals the Faber-Jackson relation parameters change systematically, ii) non-parametric tests show that the fluctuations in the values of the slope of the Faber-Jackson relation are not products of chance variations. Conclusions: We conclude that the values of the Faber-Jackson relation parameters depend on the width of the magnitude range and the luminosity of galaxies within the magnitude range. This dependence is caused, to a great extent by the selection effects and because the geometrical shape of the distribution of galaxies on the M - log(σ0) plane depends on luminosity. We therefore emphasize that if the luminosity of galaxies or the width of the magnitude range or both are not taken into consideration when comparing the structural relations of galaxy samples for different wavelengths, environments, redshifts and luminosities, any differences found may be misinterpreted.

  17. A Monte Carlo Method for Making the SDSS u-Band Magnitude More Accurate

    NASA Astrophysics Data System (ADS)

    Gu, Jiayin; Du, Cuihua; Zuo, Wenbo; Jing, Yingjie; Wu, Zhenyu; Ma, Jun; Zhou, Xu

    2016-10-01

    We develop a new Monte Carlo-based method to convert the Sloan Digital Sky Survey (SDSS) u-band magnitude to the south Galactic Cap of the u-band Sky Survey (SCUSS) u-band magnitude. Due to the increased accuracy of SCUSS u-band measurements, the converted u-band magnitude becomes more accurate compared with the original SDSS u-band magnitude, in particular at the faint end. The average u-magnitude error (for both SDSS and SCUSS) of numerous main-sequence stars with 0.2\\lt g-r\\lt 0.8 increases as the g-band magnitude becomes fainter. When g = 19.5, the average magnitude error of the SDSS u is 0.11. When g = 20.5, the average SDSS u error rises to 0.22. However, at this magnitude, the average magnitude error of the SCUSS u is just half as much as that of the SDSS u. The SDSS u-band magnitudes of main-sequence stars with 0.2\\lt g-r\\lt 0.8 and 18.5\\lt g\\lt 20.5 are converted, therefore the maximum average error of the converted u-band magnitudes is 0.11. The potential application of this conversion is to derive a more accurate photometric metallicity calibration from SDSS observations, especially for the more distant stars. Thus, we can explore stellar metallicity distributions either in the Galactic halo or some stream stars.

  18. Quantifying Surface Processes and Stratigraphic Characteristics Resulting from Large Magnitude High Frequency and Small Magnitude Low Frequency Relative Sea Level Cycles: An Experimental Study

    NASA Astrophysics Data System (ADS)

    Yu, L.; Li, Q.; Esposito, C. R.; Straub, K. M.

    2015-12-01

    Relative Sea-Level (RSL) change, which is a primary control on sequence stratigraphic architecture, has a close relationship with climate change. In order to explore the influence of RSL change on the stratigraphic record, we conducted three physical experiments which shared identical boundary conditions but differed in their RSL characteristics. Specifically, the three experiments differed with respect to two non-dimensional numbers that compare the magnitude and periodicity of RSL cycles to the spatial and temporal scales of autogenic processes, respectively. The magnitude of RSL change is quantified with H*, defined as the peak to trough difference in RSL during a cycle divided by a system's maximum autogenic channel depth. The periodicity of RSL change is quantified with T*, defined as the period of RSL cycles divided by the time required to deposit one channel depth of sediment, on average, everywhere in the basin. Experiments performed included: 1) a control experiment lacking RSL cycles, used to define a system's autogenics, 2) a high magnitude, high frequency RSL cycles experiment, and 3) a low magnitude, low frequency cycles experiment. We observe that the high magnitude, high frequency experiment resulted in the thickest channel bodies with the lowest width-to-depth ratios, while the low magnitude, long period experiment preserves a record of gradual shoreline transgression and regression producing facies that are the most continuous in space. We plan to integrate our experimental results with Delft3D numerical experiments models that sample similar non-dimensional characteristics of RSL cycles. Quantifying the influence of RSL change, normalized as a function of the spatial and temporal scales of autogenic processes will strengthen our ability to predict stratigraphic architecture and invert stratigraphy for paleo-environmental conditions.

  19. Scaling of frequency-magnitude distributions of fluid-induced seismicity

    NASA Astrophysics Data System (ADS)

    Dinske, Carsten; Shapiro, Serge A.

    2015-04-01

    We compare b value and seismogenic index Σ estimates using two different approaches: a standard Gutenberg-Richter power-law fitting and a frequency-magnitude lower bound probability fitting. The latter takes into account the finite size of the perturbed rock volume. Our results reveal that the smaller is the perturbed rock volume the larger are the deviations between the two sets of derived parameters. It means that the magnitude statistics of the induced events is most affected for low injection volumes and/or short injection times. In sufficiently large stimulated volumes both fitting approaches provide comparable b value and seismogenic index estimates. In particular, the b value is then in the range universally obtained for tectonic earthquakes (b 0.8 - 1.2). We introduce the specific magnitude MΣ as a seismotectonic characteristic of a reservoir location. Defined as the ratio between seismogenic index Σ and b value, this magnitude scaling parameter is unaffected by the size of perturbed rock volumes. Using both seismogenic index model and specific magnitude model we predict frequency-magnitude distributions for two different scenarios and compare these to observed data. We conclude that the seismogenic index model provides reliable predictions which confirm its applicability as a forecast tool. On the other hand, the specific magnitude model can be applied to predict the asymptotical limit of probable frequency-magnitude distributions.

  20. Relations of Different Types of Numerical Magnitude Representations to Each Other and to Mathematics Achievement

    ERIC Educational Resources Information Center

    Fazio, Lisa K.; Bailey, Drew H.; Thompson, Clarissa A.; Siegler, Robert S.

    2014-01-01

    We examined relations between symbolic and non-symbolic numerical magnitude representations, between whole number and fraction representations, and between these representations and overall mathematics achievement in fifth graders. Fraction and whole number symbolic and non-symbolic numerical magnitude understandings were measured using both…

  1. Involvement of Working Memory in Longitudinal Development of Number-Magnitude Skills

    ERIC Educational Resources Information Center

    Kolkman, Meijke E.; Kroesbergen, Evelyn H.; Leseman, Paul P. M.

    2014-01-01

    The ability to connect numbers and magnitudes is an important prerequisite for math learning, here referred to as number-magnitude skills. It has been proposed that working memory plays an important role in constructing these connections. The aim of the current study was to examine if working memory accounts for constructing these connections by…

  2. 48 CFR 436.204 - Disclosure of the magnitude of construction projects.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... magnitude of construction projects. 436.204 Section 436.204 Federal Acquisition Regulations System DEPARTMENT OF AGRICULTURE SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS Special Aspects of Contracting for Construction 436.204 Disclosure of the magnitude of...

  3. 48 CFR 36.204 - Disclosure of the magnitude of construction projects.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... magnitude of construction projects. 36.204 Section 36.204 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS Special Aspects of Contracting for Construction 36.204 Disclosure of the magnitude of construction...

  4. 48 CFR 36.204 - Disclosure of the magnitude of construction projects.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... magnitude of construction projects. 36.204 Section 36.204 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS Special Aspects of Contracting for Construction 36.204 Disclosure of the magnitude of construction...

  5. 48 CFR 36.204 - Disclosure of the magnitude of construction projects.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... magnitude of construction projects. 36.204 Section 36.204 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS Special Aspects of Contracting for Construction 36.204 Disclosure of the magnitude of construction...

  6. 48 CFR 236.204 - Disclosure of the magnitude of construction projects.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... magnitude of construction projects. 236.204 Section 236.204 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND... magnitude of construction projects. Additional price ranges are— (i) Between $10,000,000 and...

  7. 48 CFR 436.204 - Disclosure of the magnitude of construction projects.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... magnitude of construction projects. 436.204 Section 436.204 Federal Acquisition Regulations System DEPARTMENT OF AGRICULTURE SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS Special Aspects of Contracting for Construction 436.204 Disclosure of the magnitude of...

  8. 48 CFR 236.204 - Disclosure of the magnitude of construction projects.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... magnitude of construction projects. 236.204 Section 236.204 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND... magnitude of construction projects. Additional price ranges are— (i) Between $10,000,000 and...

  9. 48 CFR 436.204 - Disclosure of the magnitude of construction projects.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... magnitude of construction projects. 436.204 Section 436.204 Federal Acquisition Regulations System DEPARTMENT OF AGRICULTURE SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS Special Aspects of Contracting for Construction 436.204 Disclosure of the magnitude of...

  10. 48 CFR 236.204 - Disclosure of the magnitude of construction projects.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... magnitude of construction projects. 236.204 Section 236.204 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND... magnitude of construction projects. Additional price ranges are— (i) Between $10,000,000 and...

  11. 48 CFR 236.204 - Disclosure of the magnitude of construction projects.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... magnitude of construction projects. 236.204 Section 236.204 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND... magnitude of construction projects. Additional price ranges are— (i) Between $10,000,000 and...

  12. 48 CFR 36.204 - Disclosure of the magnitude of construction projects.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... magnitude of construction projects. 36.204 Section 36.204 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS Special Aspects of Contracting for Construction 36.204 Disclosure of the magnitude of construction...

  13. 48 CFR 436.204 - Disclosure of the magnitude of construction projects.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... magnitude of construction projects. 436.204 Section 436.204 Federal Acquisition Regulations System DEPARTMENT OF AGRICULTURE SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS Special Aspects of Contracting for Construction 436.204 Disclosure of the magnitude of...

  14. 48 CFR 436.204 - Disclosure of the magnitude of construction projects.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... magnitude of construction projects. 436.204 Section 436.204 Federal Acquisition Regulations System DEPARTMENT OF AGRICULTURE SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS Special Aspects of Contracting for Construction 436.204 Disclosure of the magnitude of...

  15. 48 CFR 236.204 - Disclosure of the magnitude of construction projects.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... magnitude of construction projects. 236.204 Section 236.204 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND... magnitude of construction projects. Additional price ranges are— (i) Between $10,000,000 and...

  16. 48 CFR 36.204 - Disclosure of the magnitude of construction projects.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... magnitude of construction projects. 36.204 Section 36.204 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER CONTRACTS Special Aspects of Contracting for Construction 36.204 Disclosure of the magnitude of construction...

  17. Fractions as percepts? Exploring cross-format distance effects for fractional magnitudes.

    PubMed

    Matthews, Percival G; Chesney, Dana L

    2015-05-01

    This study presents evidence that humans have intuitive, perceptually based access to the abstract fraction magnitudes instantiated by nonsymbolic ratio stimuli. Moreover, it shows these perceptually accessed magnitudes can be easily compared with symbolically represented fractions. In cross-format comparisons, participants picked the larger of two ratios. Ratios were presented either symbolically as fractions or nonsymbolically as paired dot arrays or as paired circles. Response patterns were consistent with participants comparing specific analog fractional magnitudes independently of the particular formats in which they were presented. These results pose a challenge to accounts that argue human cognitive architecture is ill-suited for processing fractions. Instead, it seems that humans can process nonsymbolic ratio magnitudes via perceptual routes and without recourse to conscious symbolic algorithms, analogous to the processing of whole number magnitudes. These findings have important implications for theories regarding the nature of human number sense - they imply that fractions may in some sense be natural numbers, too.

  18. Relations of different types of numerical magnitude representations to each other and to mathematics achievement.

    PubMed

    Fazio, Lisa K; Bailey, Drew H; Thompson, Clarissa A; Siegler, Robert S

    2014-07-01

    We examined relations between symbolic and non-symbolic numerical magnitude representations, between whole number and fraction representations, and between these representations and overall mathematics achievement in fifth graders. Fraction and whole number symbolic and non-symbolic numerical magnitude understandings were measured using both magnitude comparison and number line estimation tasks. After controlling for non-mathematical cognitive proficiency, both symbolic and non-symbolic numerical magnitude understandings were uniquely related to mathematics achievement, but the relation was much stronger for symbolic numbers. A meta-analysis of 19 published studies indicated that relations between non-symbolic numerical magnitude knowledge and mathematics achievement are present but tend to be weak, especially beyond 6 years of age.

  19. Maximum Magnitude and Recurrence Interval for the Large Earthquakes in the Central and Eastern United States

    NASA Astrophysics Data System (ADS)

    Wang, Z.; Hu, C.

    2012-12-01

    Maximum magnitude and recurrence interval of the large earthquakes are key parameters for seismic hazard assessment in the central and eastern United States. Determination of these two parameters is quite difficult in the region, however. For example, the estimated maximum magnitudes of the 1811-12 New Madrid sequence are in the range of M6.6 to M8.2, whereas the estimated recurrence intervals are in the range of about 500 to several thousand years. These large variations of maximum magnitude and recurrence interval for the large earthquakes lead to significant variation of estimated seismic hazards in the central and eastern United States. There are several approaches being used to estimate the magnitudes and recurrence intervals, such as historical intensity analysis, geodetic data analysis, and paleo-seismic investigation. We will discuss the approaches that are currently being used to estimate maximum magnitude and recurrence interval of the large earthquakes in the central United States.

  20. Application of magnitude estimation scaling to the assessment of subjective loudness response to simulated sonic booms

    NASA Technical Reports Server (NTRS)

    Mcdaniel, S.; Leatherwood, J. D.; Sullivan, B. M.

    1992-01-01

    A laboratory study was conducted for the following reasons: (1) to investigate the application of magnitude estimation scaling for evaluating the subjective loudness of sonic booms; and (2) to compare the relative merits of magnitude estimation and numerical category scaling for sonic boom loudness evaluation. The study was conducted in the NASA LeRC's sonic boom simulator and used a total of 80 test subjects (48 for magnitude estimation and 32 for numerical category scaling). Results demonstrated that magnitude estimation was a practical and effective method for quantifying subjective loudness of sonic booms. When using magnitude estimation, the subjects made valid and consistent ratio judgments of sonic boom loudness irrespective of the frequency of presentation of the standard stimulus. Presentation of the standard as every fourth stimulus was preferred by the subjects and is recommended as the standard presentation frequency to be used in future tests.

  1. Characterization of sleep stages by correlations in the magnitude and sign of heartbeat increments

    NASA Astrophysics Data System (ADS)

    Kantelhardt, Jan W.; Ashkenazy, Yosef; Ivanov, Plamen Ch.; Bunde, Armin; Havlin, Shlomo; Penzel, Thomas; Peter, Jörg-Hermann; Stanley, H. Eugene

    2002-05-01

    We study correlation properties of the magnitude and the sign of the increments in the time intervals between successive heartbeats during light sleep, deep sleep, and rapid eye movement (REM) sleep using the detrended fluctuation analysis method. We find short-range anticorrelations in the sign time series, which are strong during deep sleep, weaker during light sleep, and even weaker during REM sleep. In contrast, we find long-range positive correlations in the magnitude time series, which are strong during REM sleep and weaker during light sleep. We observe uncorrelated behavior for the magnitude during deep sleep. Since the magnitude series relates to the nonlinear properties of the original time series, while the sign series relates to the linear properties, our findings suggest that the nonlinear properties of the heartbeat dynamics are more pronounced during REM sleep. Thus, the sign and the magnitude series provide information which is useful in distinguishing between the sleep stages.

  2. Soluciones analiticas AL problema de jets con velocidad de eyeccion variable EN EL tiempo.

    NASA Astrophysics Data System (ADS)

    Canto, J.; Raga, A. C.; D'Alessio, P.

    1998-11-01

    Se presenta un nuevo metodo que permite resolver de manera exacta y analitica las ecuaciones que describen un jet hipersonico con velocidad de eyeccion variable en el tiempo. El metodo se basa en consideraciones sencillas de conservacion de momento para las superficies de trabajo que se forman en el interior del jet. Como ejemplo, se presentan soluciones para jets con variacion sinusoidal en la velocidad de eyeccion, y tambien para el caso de un incremento lineal en el tiempo. Estas soluciones analiticas tienen una clara aplicacion en la interpretacion de las observaciones de jets asociados a objetos Herbig-Haro.

  3. Preguntas y respuestas acerca del Estudio del

    Cancer.gov

    El Estudio del Tamoxifeno y Raloxifeno (STAR, por sus siglas en ingls) es un estudio clnico (un estudio de investigacin conducido con voluntarios) diseado para ver cómo el medicamento raloxifeno (Evista) se compara con el medicamento tamoxifeno (Nolvadex)

  4. How to assess magnitudes of paleo-earthquakes from multiple observations

    NASA Astrophysics Data System (ADS)

    Hintersberger, Esther; Decker, Kurt

    2016-04-01

    An important aspect of fault characterisation regarding seismic hazard assessment are paleo-earthquake magnitudes. Especially in regions with low or moderate seismicity, paleo-magnitudes are normally much larger than those of historical earthquakes and therefore provide essential information about seismic potential and expected maximum magnitudes of a certain region. In general, these paleo-earthquake magnitudes are based either on surface rupture length or on surface displacement observed at trenching sites. Several well-established correlations provide the possibility to link the observed surface displacement to a certain magnitude. However, the combination of more than one observation is still rare and not well established. We present here a method based on a probabilistic approach proposed by Biasi and Weldon (2006) to combine several observations to better constrain the possible magnitude range of a paleo-earthquake. Extrapolating the approach of Biasi and Weldon (2006), the single-observation probability density functions (PDF) are assumed to be independent of each other. Following this line, the common PDF for all observed surface displacements generated by one earthquake is the product of all single-displacement PDFs. In order to test our method, we use surface displacement data for modern earthquakes, where magnitudes have been determined by instrumental records. For randomly selected "observations", we calculated the associated PDFs for each "observation point". We then combined the PDFs into one common PDF for an increasing number of "observations". Plotting the most probable magnitudes against the number of combined "observations", the resultant range of most probable magnitudes is very close to the magnitude derived by instrumental methods. Testing our method with real trenching observations, we used the results of a paleoseismological investigation within the Vienna Pull-Apart Basin (Austria), where three trenches were opened along the normal

  5. Magnitude Problems in Historical Earthquake Catalogs and Their Impact on Seismic Hazard Assessment

    NASA Astrophysics Data System (ADS)

    Rong, Y.; Mahdyiar, M.; Shen-Tu, B.; Shabestari, K.; Guin, J.

    2010-12-01

    A reliable historical earthquake catalog is a critical component for any regional seismic hazard analysis. In Europe, a number of historical earthquake catalogs have been compiled and used in constructing national or regional seismic hazard maps, for instance, Switzerland ECOS catalog by Swiss Seismological Service (2002), Italy CPTI catalog by CPTI Working Group (2004), Greece catalog by Papazachos et al. (2007), and CENEC (central, northern and northwestern Europe) catalog by Grünthal et al. (2009), Turkey catalog by Kalafat et al. (2007), and GSHAP catalog by Global Seismic Hazard Assessment Program (1999). These catalogs spatially overlap with each other to a large extent and employed a uniform magnitude scale (Mw). A careful review of these catalogs has revealed significant magnitude problems which can substantially impact regional seismic hazard assessment: 1) Magnitudes for the same earthquakes in different catalogs are discrepant. Such discrepancies are mainly driven by different regression relationships used to convert other magnitude scales or intensity into Mw. One of the consequences is magnitudes of many events in one catalog are systematically biased higher or lower with respect to those in another catalog. For example, the magnitudes of large historical earthquakes in the Italy CPTI catalog are systematically higher than those in Switzerland ECOS catalog. 2) Abnormally high frequency of large magnitude events is observed for some time period that intensities are the main available data. This phenomenon is observed in Italy CPTI catalog for the time period of 1870 to 1930. This may be due to biased conversion from intensity to magnitude. 3) A systematic bias in magnitude resulted in biased estimations for a- and b-values of the Gutenberg-Richter magnitude frequency relationships. It also affected the determination of upper bound magnitudes for various seismic source zones. All of these issues can lead to skewed seismic hazard results, or inconsistent

  6. Magnitude and sign of long-range correlated time series: Decomposition and surrogate signal generation.

    PubMed

    Gómez-Extremera, Manuel; Carpena, Pedro; Ivanov, Plamen Ch; Bernaola-Galván, Pedro A

    2016-04-01

    We systematically study the scaling properties of the magnitude and sign of the fluctuations in correlated time series, which is a simple and useful approach to distinguish between systems with different dynamical properties but the same linear correlations. First, we decompose artificial long-range power-law linearly correlated time series into magnitude and sign series derived from the consecutive increments in the original series, and we study their correlation properties. We find analytical expressions for the correlation exponent of the sign series as a function of the exponent of the original series. Such expressions are necessary for modeling surrogate time series with desired scaling properties. Next, we study linear and nonlinear correlation properties of series composed as products of independent magnitude and sign series. These surrogate series can be considered as a zero-order approximation to the analysis of the coupling of magnitude and sign in real data, a problem still open in many fields. We find analytical results for the scaling behavior of the composed series as a function of the correlation exponents of the magnitude and sign series used in the composition, and we determine the ranges of magnitude and sign correlation exponents leading to either single scaling or to crossover behaviors. Finally, we obtain how the linear and nonlinear properties of the composed series depend on the correlation exponents of their magnitude and sign series. Based on this information we propose a method to generate surrogate series with controlled correlation exponent and multifractal spectrum.

  7. Development of magnitude processing in children with developmental dyscalculia: space, time, and number.

    PubMed

    Skagerlund, Kenny; Träff, Ulf

    2014-01-01

    Developmental dyscalculia (DD) is a learning disorder associated with impairments in a preverbal non-symbolic approximate number system (ANS) pertaining to areas in and around the intraparietal sulcus (IPS). The current study sought to enhance our understanding of the developmental trajectory of the ANS and symbolic number processing skills, thereby getting insight into whether a deficit in the ANS precedes or is preceded by impaired symbolic and exact number processing. Recent work has also suggested that humans are endowed with a shared magnitude system (beyond the number domain) in the brain. We therefore investigated whether children with DD demonstrated a general magnitude deficit, stemming from the proposed magnitude system, rather than a specific one limited to numerical quantity. Fourth graders with DD were compared to age-matched controls and a group of ability-matched second graders, on a range of magnitude processing tasks pertaining to space, time, and number. Children with DD displayed difficulties across all magnitude dimensions compared to age-matched peers and showed impaired ANS acuity compared to the younger, ability-matched control group, while exhibiting intact symbolic number processing. We conclude that (1) children with DD suffer from a general magnitude-processing deficit, (2) a shared magnitude system likely exists, and (3) a symbolic number-processing deficit in DD tends to be preceded by an ANS deficit. PMID:25018746

  8. Magnitude and frequency of floods in Alaska south of the Yukon River

    USGS Publications Warehouse

    Berwick, Vernon Kenneth; Childers, Joseph M.; Kuentzel, M.A.

    1964-01-01

    This report presents a method for evaluating the magnitude and frequency of floods on the basis of the analysis of flood records. One composite frequency curve is applied to the entire study region. This curve relates floods of various magnitudes at any site within the region to probable recurrence intervals (from 1.1 to 50 years) for those floods. Flood magnitudes are reduced to dimensionless form by expressing them as a ratio to mean annual flood. Magnitudes of mean annual floods vary with the flood-producing characteristics of stream basins. On the basis of the limited data available, drainage-area size is found to be the only significant factor affecting the magnitude of the mean annual flood. Trial and error groupings of gaging-station records show that the region can be split into three hydrologic areas: one curve defines the relation within each area between mean annual flood and drainage area. These three curves in combination with the composite flood-frequency curve permit, for natural-flow conditions at any site, the determination of flood magnitude for a given recurrence interval, or the determination of recurrence interval for a flood of known magnitude.

  9. Magnitude and sign of long-range correlated time series: Decomposition and surrogate signal generation.

    PubMed

    Gómez-Extremera, Manuel; Carpena, Pedro; Ivanov, Plamen Ch; Bernaola-Galván, Pedro A

    2016-04-01

    We systematically study the scaling properties of the magnitude and sign of the fluctuations in correlated time series, which is a simple and useful approach to distinguish between systems with different dynamical properties but the same linear correlations. First, we decompose artificial long-range power-law linearly correlated time series into magnitude and sign series derived from the consecutive increments in the original series, and we study their correlation properties. We find analytical expressions for the correlation exponent of the sign series as a function of the exponent of the original series. Such expressions are necessary for modeling surrogate time series with desired scaling properties. Next, we study linear and nonlinear correlation properties of series composed as products of independent magnitude and sign series. These surrogate series can be considered as a zero-order approximation to the analysis of the coupling of magnitude and sign in real data, a problem still open in many fields. We find analytical results for the scaling behavior of the composed series as a function of the correlation exponents of the magnitude and sign series used in the composition, and we determine the ranges of magnitude and sign correlation exponents leading to either single scaling or to crossover behaviors. Finally, we obtain how the linear and nonlinear properties of the composed series depend on the correlation exponents of their magnitude and sign series. Based on this information we propose a method to generate surrogate series with controlled correlation exponent and multifractal spectrum. PMID:27176287

  10. Revised magnitude-bound relation for the Wabash Valley seismic zone of the central United States

    USGS Publications Warehouse

    Olson, S.M.; Green, R.A.; Obermeier, S.F.

    2005-01-01

    Seismic hazard assessment in the central United States, and in particular the Wabash Valley seismic zone of Indiana-Illinois, frequently relies on empirical estimates of paleoearthquake magnitudes (M). In large part these estimates have been made using the magnitude-bound method. Existing region-specific magnitude-bound relations rely heavily on only a few historical earthquakes in the central United States and eastern Canada that induced reported liquefaction features. Recent seismological studies have suggested smaller magnitudes than previously presumed for some of these earthquakes, however, and other studies have reinterpreted site-to-source distances to liquefaction features associated with some of these earthquakes. In this paper, we re-examine historical earthquakes (M > ???5) that occurred in the central and eastern United States and eastern Canada; some of these earthquakes triggered liquefaction and others did not. Based on our findings, we reinterpret the region-specific magnitude-bound relation for the Wabash Valley. Using this revised magnitude-bound relation, we present magnitude estimates for four prehistoric earthquakes that occurred in the Wabash Valley seismic zone during Holocene time.

  11. Development of magnitude processing in children with developmental dyscalculia: space, time, and number

    PubMed Central

    Skagerlund, Kenny; Träff, Ulf

    2014-01-01

    Developmental dyscalculia (DD) is a learning disorder associated with impairments in a preverbal non-symbolic approximate number system (ANS) pertaining to areas in and around the intraparietal sulcus (IPS). The current study sought to enhance our understanding of the developmental trajectory of the ANS and symbolic number processing skills, thereby getting insight into whether a deficit in the ANS precedes or is preceded by impaired symbolic and exact number processing. Recent work has also suggested that humans are endowed with a shared magnitude system (beyond the number domain) in the brain. We therefore investigated whether children with DD demonstrated a general magnitude deficit, stemming from the proposed magnitude system, rather than a specific one limited to numerical quantity. Fourth graders with DD were compared to age-matched controls and a group of ability-matched second graders, on a range of magnitude processing tasks pertaining to space, time, and number. Children with DD displayed difficulties across all magnitude dimensions compared to age-matched peers and showed impaired ANS acuity compared to the younger, ability-matched control group, while exhibiting intact symbolic number processing. We conclude that (1) children with DD suffer from a general magnitude-processing deficit, (2) a shared magnitude system likely exists, and (3) a symbolic number-processing deficit in DD tends to be preceded by an ANS deficit. PMID:25018746

  12. Stability of individual loudness functions obtained by magnitude estimation and production

    NASA Technical Reports Server (NTRS)

    Hellman, R. P.

    1981-01-01

    A correlational analysis of individual magnitude estimation and production exponents at the same frequency is performed, as is an analysis of individual exponents produced in different sessions by the same procedure across frequency (250, 1000, and 3000 Hz). Taken as a whole, the results show that individual exponent differences do not decrease by counterbalancing magnitude estimation with magnitude production and that individual exponent differences remain stable over time despite changes in stimulus frequency. Further results show that although individual magnitude estimation and production exponents do not necessarily obey the .6 power law, it is possible to predict the slope of an equal-sensation function averaged for a group of listeners from individual magnitude estimation and production data. On the assumption that individual listeners with sensorineural hearing also produce stable and reliable magnitude functions, it is also shown that the slope of the loudness-recruitment function measured by magnitude estimation and production can be predicted for individuals with bilateral losses of long duration. Results obtained in normal and pathological ears thus suggest that individual listeners can produce loudness judgements that reveal, although indirectly, the input-output characteristic of the auditory system.

  13. Estimating earthquake magnitudes from reported intensities in the central and eastern United States

    USGS Publications Warehouse

    Boyd, Oliver; Cramer, Chris H.

    2014-01-01

    A new macroseismic intensity prediction equation is derived for the central and eastern United States and is used to estimate the magnitudes of the 1811–1812 New Madrid, Missouri, and 1886 Charleston, South Carolina, earthquakes. This work improves upon previous derivations of intensity prediction equations by including additional intensity data, correcting magnitudes in the intensity datasets to moment magnitude, and accounting for the spatial and temporal population distributions. The new relation leads to moment magnitude estimates for the New Madrid earthquakes that are toward the lower range of previous studies. Depending on the intensity dataset to which the new macroseismic intensity prediction equation is applied, mean estimates for the 16 December 1811, 23 January 1812, and 7 February 1812 mainshocks, and 16 December 1811 dawn aftershock range from 6.9 to 7.1, 6.8 to 7.1, 7.3 to 7.6, and 6.3 to 6.5, respectively. One‐sigma uncertainties on any given estimate could be as high as 0.3–0.4 magnitude units. We also estimate a magnitude of 6.9±0.3 for the 1886 Charleston, South Carolina, earthquake. We find a greater range of magnitude estimates when also accounting for multiple macroseismic intensity prediction equations. The inability to accurately and precisely ascertain magnitude from intensities increases the uncertainty of the central United States earthquake hazard by nearly a factor of two. Relative to the 2008 national seismic hazard maps, our range of possible 1811–1812 New Madrid earthquake magnitudes increases the coefficient of variation of seismic hazard estimates for Memphis, Tennessee, by 35%–42% for ground motions expected to be exceeded with a 2% probability in 50 years and by 27%–35% for ground motions expected to be exceeded with a 10% probability in 50 years.

  14. Understanding the magnitude dependence of PGA and PGV in NGA-West 2 data

    USGS Publications Warehouse

    Baltay, Annemarie S.; Hanks, Thomas C.

    2014-01-01

    The Next Generation Attenuation‐West 2 (NGA‐West 2) 2014 ground‐motion prediction equations (GMPEs) model ground motions as a function of magnitude and distance, using empirically derived coefficients (e.g., Bozorgniaet al., 2014); as such, these GMPEs do not clearly employ earthquake source parameters beyond moment magnitude (M) and focal mechanism. To better understand the magnitude‐dependent trends in the GMPEs, we build a comprehensive earthquake source‐based model to explain the magnitude dependence of peak ground acceleration and peak ground velocity in the NGA‐West 2 ground‐motion databases and GMPEs. Our model employs existing models (Hanks and McGuire, 1981; Boore, 1983, 1986; Anderson and Hough, 1984) that incorporate a point‐source Brune model, including a constant stress drop and the high‐frequency attenuation parameter κ0, random vibration theory, and a finite‐fault assumption at the large magnitudes to describe the data from magnitudes 3 to 8. We partition this range into four different magnitude regions, each of which has different functional dependences on M. Use of the four magnitude partitions separately allows greater understanding of what happens in any one subrange, as well as the limiting conditions between the subranges. This model provides a remarkably good fit to the NGA data for magnitudes from 3magnitude data, for which the corner frequency is masked by the attenuation of high frequencies. That this simple, source‐based model matches the NGA‐West 2 GMPEs and data so well suggests that considerable simplicity underlies the parametrically complex NGA GMPEs.

  15. Empirical conversion between teleseismic magnitudes (mb and Ms) and moment magnitude (Mw) at the Global, Euro-Mediterranean and Italian scale

    NASA Astrophysics Data System (ADS)

    Lolli, B.; Gasperini, P.; Vannucci, G.

    2014-11-01

    We analysed the conversion problem between teleseismic magnitudes (Ms and mb) provided by the Seismological Bulletin of the International Seismological Centre and moment magnitudes (Mw) provided by online moment tensor (MT) catalogues using the chi-square general orthogonal regression method (CSQ) that, differently from the ordinary least-square regression method (OLS), accounts for the measurement errors of both the predictor and response variables. To account for the non-linearity of the relationships, we used two types of curvilinear models: (i) the exponential model (EXP), recently proposed by the authors of the Global Catalogue sponsored by the Global Earthquake Model (GEM) Foundation and (ii) a connected bilinear (CBL) model, similar to that proposed by Ekström & Dziewonski, where two different linear trends at low and high magnitudes are connected by an arc of circle that preserves the continuity of the function and of its first derivative at the connecting points. For Ms, we found that the regression curves computed for a global data set (GBL) are likely to be biased by the incompleteness of global MT catalogues for Mw <5.0-5.5. In fact, the GBL curves deviate significantly from a similar regression curve computed for a Euro-Mediterranean data set (MED) integrated with the data provided by two regional MT catalogues including many more events with Mw < 5.0-5.5. The GLB regression curves overestimate the Mw proxies computed from Ms up to 0.5 magnitude units. Hence for computing Mw proxies at the global scale of Ms ≤ 5.5, we suggest to adopt the coefficients obtained from the MED regression. The analysis of the frequency-magnitude relationship of the resulting Mw proxy catalogues confirms the validity of this choice as the behaviour of b­-value as a function of cut-off magnitude of the GBL data set is much more stable using such approach. The incompleteness of Mw's provided from MT global catalogues also affects the mb GBL data set but in this case the

  16. Magnitude calibration of a fixed head star tracker using Astro-1 flight data

    NASA Technical Reports Server (NTRS)

    Rakoczy, John M.; West, Mark E.

    1992-01-01

    The Astro-1 UV astronomy mission was hampered by the failures of the automatic star acquisition procedure. The acquisition procedure depended on the Instrument Pointing Subsystem's Fixed Head Star Trackers (FHST) to acquire, track and identify guidestars of known visual magnitude. During the Astro-1 mission it was suspected that the star magnitudes measured by the FHST were much lower than predicted. A postflight investigation of the Astro-1 flight data confirmed and quantified this suspicion. Star magnitude calibration curves computed from the flight data depict the variance from the preflight calibration curves. These results are helping engineers to plan improvements to the acquisition procedure for the upcoming Astro-2 mission.

  17. Freshwater discharge into the Caribbean Sea from the rivers of Northwestern South America (Colombia): Magnitude, variability and recent changes

    NASA Astrophysics Data System (ADS)

    Restrepo, Juan Camilo; Ortíz, Juan Carlos; Pierini, Jorge; Schrottke, Kerstin; Maza, Mauro; Otero, Luís; Aguirre, Julián

    2014-02-01

    The monthly averaged freshwater discharge data from ten rivers in northern Colombia (Caribbean alluvial plain) draining into the Caribbean Sea were analysed to quantify the magnitudes, to estimate long-term trends, and to evaluate the variability of discharge patterns. These rivers deliver ∼340.9 km3 yr-1 of freshwater to the Caribbean Sea. The largest freshwater supply is provided by the Magdalena River, with a mean discharge of 205.1 km3 yr-1 at Calamar, which is 26% of the total fluvial discharge into this basin. From 2000 to 2010, the annual streamflow of these rivers increased as high as 65%, and upward trends in statistical significance were found for the Mulatos, Canal del Dique, Magdalena, and Fundación Rivers. The concurrence of major oscillation processes and the maximum power of the 3-7 year band fluctuation defined a period of intense hydrological activity from approximately 1998-2002. The wavelet spectrum highlighted a change in the variability patterns of fluvial systems between 2000 and 2010 characterised by a shift towards a quasi-decadal process (8-12 years) domain. The Intertropical Convergence Zone (ITCZ), El Niño - Southern Oscillation (ENSO) events, and quasi-decadal climate processes are the main factors controlling the fluvial discharge variability of these fluvial systems.

  18. Moment magnitude, local magnitude and corner frequency of small earthquakes nucleating along a low angle normal fault in the Upper Tiber valley (Italy)

    NASA Astrophysics Data System (ADS)

    Munafo, I.; Malagnini, L.; Chiaraluce, L.; Valoroso, L.

    2015-12-01

    The relation between moment magnitude (MW) and local magnitude (ML) is still a debated issue (Bath, 1966, 1981; Ristau et al., 2003, 2005). Theoretical considerations and empirical observations show that, in the magnitude range between 3 and 5, MW and ML scale 1∶1. Whilst for smaller magnitudes this 1∶1 scaling breaks down (Bethmann et al. 2011). For accomplishing this task we analyzed the source parameters of about 1500 (30.000 waveforms) well-located small earthquakes occurred in the Upper Tiber Valley (Northern Apennines) in the range of -1.5≤ML≤3.8. In between these earthquakes there are 300 events repeatedly rupturing the same fault patch generally twice within a short time interval (less than 24 hours; Chiaraluce et al., 2007). We use high-resolution short period and broadband recordings acquired between 2010 and 2014 by 50 permanent seismic stations deployed to monitor the activity of a regional low angle normal fault (named Alto Tiberina fault, ATF) in the framework of The Alto Tiberina Near Fault Observatory project (TABOO; Chiaraluce et al., 2014). For this study the direct determination of MW for small earthquakes is essential but unfortunately the computation of MW for small earthquakes (MW < 3) is not a routine procedure in seismology. We apply the contributions of source, site, and crustal attenuation computed for this area in order to obtain precise spectral corrections to be used in the calculation of small earthquakes spectral plateaus. The aim of this analysis is to achieve moment magnitudes of small events through a procedure that uses our previously calibrated crustal attenuation parameters (geometrical spreading g(r), quality factor Q(f), and the residual parameter k) to correct for path effects. We determine the MW-ML relationships in two selected fault zones (on-fault and fault-hanging-wall) of the ATF by an orthogonal regression analysis providing a semi-automatic and robust procedure for moment magnitude determination within a

  19. Floods in Georgia, magnitude and frequency : techniques for estimating the magnitude and frequency of floods in Georgia with compilation of flood data through 1974

    USGS Publications Warehouse

    Price, McGlone

    1979-01-01

    Regional relations are defined for estimating the magnitude and frequency of floods having recurrence intervals of 2, 5, 10, 25, 50, and 100 years on streams with natural flow in Georgia. Multiple-regression analyses were used to define the relationship between the flood-discharge frequency of annual peak discharges for streams draining 0.1 to 1,000 square miles and 10 climatological and physical basin characteristics. The analyses indicate that the drainage area of the basin is the most significant characteristic. Five regions having distinct flood-discharge frequency characteristics are delineated. Individual relations of flood magnitude and frequency to drainage area are given for parts of the main stems of the major rivers without significant regulation draining more than 1,000 square miles. (Kosco-USGS)

  20. A local earthquake coda magnitude and its relation to duration, moment M sub O, and local Richter magnitude M sub L

    NASA Technical Reports Server (NTRS)

    Suteau, A. M.; Whitcomb, J. H.

    1977-01-01

    A relationship was found between the seismic moment, M sub O, of shallow local earthquakes and the total duration of the signal, t, in seconds, measured from the earthquakes origin time, assuming that the end of the coda is composed of backscattering surface waves due to lateral heterogenity in the shallow crust following Aki. Using the linear relationship between the logarithm of M sub O and the local Richter magnitude M sub L, a relationship between M sub L and t, was found. This relationship was used to calculate a coda magnitude M sub C which was compared to M sub L for Southern California earthquakes which occurred during the period from 1972 to 1975.

  1. Mole Pi: Using New Technology to Teach the Magnitude of a Mole

    ERIC Educational Resources Information Center

    Geyer, Michael J.

    2014-01-01

    A modified technique for demonstrating the magnitude of Avogadro's number using a new Raspberry Pi computer and the Python language is described. The technique also provides students the opportunity to review dimensional analysis.

  2. 'Abd al-Rahman al-Sufi's 3-Step Magnitude System

    NASA Astrophysics Data System (ADS)

    Hafez, Ihsan; Stephenson, F. Richard; Orchiston, Wayne

    'Abd al-Rahmān al-ūfī's Book of the Fixed Stars dates from around AD 964 and is one of the most important medieval Arabic treatises on astronomy. In this paper we begin with a very brief introduction to the Book of the Fixed Stars. This book contains an extensive star catalogue that lists star coordinates and magnitude estimates for all of the Ptolemaic stars. However, in his book al-hūfī utilized three distinct intermediate magnitude values whereas Ptolemy only mentioned two. We believe that al-hūfī used what we have termed a '3-step intermediate magnitude system,' which is more accurate than Ptolemy's 2-step intermediate system. In this paper we examine in detail the accuracy of this unique 3-step system in comparison with Ptolemy's and modern magnitude values.

  3. Process and Object Interpretations of Vector Magnitude Mediated by Use of the Graphics Calculator.

    ERIC Educational Resources Information Center

    Forster, Patricia

    2000-01-01

    Analyzes the development of one student's understanding of vector magnitude and how her problem solving was mediated by use of the absolute value graphics calculator function. (Contains 35 references.) (Author/ASK)

  4. Has the magnitude of floods across the USA changed with global CO 2 levels?

    USGS Publications Warehouse

    Hirsch, R.M.; Ryberg, K.R.

    2012-01-01

    Statistical relationships between annual floods at 200 long-term (85-127 years of record) streamgauges in the coterminous United States and the global mean carbon dioxide concentration (GMCO2) record are explored. The streamgauge locations are limited to those with little or no regulation or urban development. The coterminous US is divided into four large regions and stationary bootstrapping is used to evaluate if the patterns of these statistical associations are significantly different from what would be expected under the null hypothesis that flood magnitudes are independent of GMCO2. In none of the four regions defined in this study is there strong statistical evidence for flood magnitudes increasing with increasing GMCO2. One region, the southwest, showed a statistically significant negative relationship between GMCO2 and flood magnitudes. The statistical methods applied compensate both for the inter-site correlation of flood magnitudes and the shorter-term (up to a few decades) serial correlation of floods.

  5. The Development of the Mental Representations of the Magnitude of Fractions

    PubMed Central

    Gabriel, Florence C.; Szucs, Denes; Content, Alain

    2013-01-01

    We investigated the development of the mental representation of the magnitude of fractions during the initial stages of fraction learning in grade 5, 6 and 7 children as well as in adults. We examined the activation of global fraction magnitude in a numerical comparison task and a matching task. There were global distance effects in the comparison task, but not in the matching task. This suggests that the activation of the global magnitude representation of fractions is not automatic in all tasks involving magnitude judgments. The slope of the global distance effect increased during early fraction learning and declined by adulthood, demonstrating that the development of the fraction global distance effect differs from that of the integer distance effect. PMID:24236169

  6. A technique for computation of star magnitudes relative to an optical sensor

    NASA Technical Reports Server (NTRS)

    Rhoads, J. W.

    1972-01-01

    The theory and techniques used to compute star magnitudes relative to any optical detector (such as the Mariner Mars 1971 Canopus star tracker) are described. Results are given relative to various star detectors.

  7. How do magnitude and frequency of monetary reward guide visual search?

    PubMed

    Won, Bo-Yeong; Leber, Andrew B

    2016-07-01

    How does reward guide spatial attention during visual search? In the present study, we examine whether and how two types of reward information-magnitude and frequency-guide search behavior. Observers were asked to find a target among distractors in a search display to earn points. We manipulated multiple levels of value across the search display quadrants in two ways: For reward magnitude, targets appeared equally often in each quadrant, and the value of each quadrant was determined by the average points earned per target; for reward frequency, we varied how often the target appeared in each quadrant but held the average points earned per target constant across the quadrants. In Experiment 1, we found that observers were highly sensitive to the reward frequency information, and prioritized their search accordingly, whereas we did not find much prioritization based on magnitude information. In Experiment 2, we found that magnitude information for a nonspatial feature (color) could bias search performance, showing that the relative insensitivity to magnitude information during visual search is not generalized across all types of information. In Experiment 3, we replicated the negligible use of spatial magnitude information even when we used limited-exposure displays to incentivize the expression of learning. In Experiment 4, we found participants used the spatial magnitude information during a modified choice task-but again not during search. Taken together, these findings suggest that the visual search apparatus does not equally exploit all potential sources of spatial value information; instead, it favors spatial reward frequency information over spatial reward magnitude information. PMID:27270595

  8. Trajectories of Symbolic and Nonsymbolic Magnitude Processing in the First Year of Formal Schooling.

    PubMed

    Matejko, Anna A; Ansari, Daniel

    2016-01-01

    Sensitivity to numerical magnitudes is thought to provide a foundation for higher-level mathematical skills such as calculation. It is still unclear how symbolic (e.g. Arabic digits) and nonsymbolic (e.g. Dots) magnitude systems develop and how the two formats relate to one another. Some theories propose that children learn the meaning of symbolic numbers by scaffolding them onto a pre-existing nonsymbolic system (Approximate Number System). Others suggest that symbolic and nonsymbolic magnitudes have distinct and non-overlapping representations. In the present study, we examine the developmental trajectories of symbolic and nonsymbolic magnitude processing skills and how they relate to each other in the first year of formal schooling when children are becoming more fluent with symbolic numbers. Thirty Grade 1 children completed symbolic and nonsymbolic magnitude processing tasks at three time points in Grade 1. We found that symbolic and nonsymbolic magnitude processing skills had distinct developmental trajectories, where symbolic magnitude processing was characterized by greater gains than nonsymbolic skills over the one-year period in Grade 1. We further found that the development of the two formats only related to one another in the first half of the school year where symbolic magnitude processing skills influenced later nonsymbolic skills. These findings indicate that symbolic and nonsymbolic abilities have different developmental trajectories and that the development of symbolic abilities is not strongly linked to nonsymbolic representations by Grade 1. These findings also suggest that the relationship between symbolic and nonsymbolic processing is not as unidirectional as previously thought.

  9. How do magnitude and frequency of monetary reward guide visual search?

    PubMed

    Won, Bo-Yeong; Leber, Andrew B

    2016-07-01

    How does reward guide spatial attention during visual search? In the present study, we examine whether and how two types of reward information-magnitude and frequency-guide search behavior. Observers were asked to find a target among distractors in a search display to earn points. We manipulated multiple levels of value across the search display quadrants in two ways: For reward magnitude, targets appeared equally often in each quadrant, and the value of each quadrant was determined by the average points earned per target; for reward frequency, we varied how often the target appeared in each quadrant but held the average points earned per target constant across the quadrants. In Experiment 1, we found that observers were highly sensitive to the reward frequency information, and prioritized their search accordingly, whereas we did not find much prioritization based on magnitude information. In Experiment 2, we found that magnitude information for a nonspatial feature (color) could bias search performance, showing that the relative insensitivity to magnitude information during visual search is not generalized across all types of information. In Experiment 3, we replicated the negligible use of spatial magnitude information even when we used limited-exposure displays to incentivize the expression of learning. In Experiment 4, we found participants used the spatial magnitude information during a modified choice task-but again not during search. Taken together, these findings suggest that the visual search apparatus does not equally exploit all potential sources of spatial value information; instead, it favors spatial reward frequency information over spatial reward magnitude information.

  10. Do Indonesian Children's Experiences with Large Currency Units Facilitate Magnitude Estimation of Long Temporal Periods?

    NASA Astrophysics Data System (ADS)

    Cheek, Kim A.

    2016-09-01

    Ideas about temporal (and spatial) scale impact students' understanding across science disciplines. Learners have difficulty comprehending the long time periods associated with natural processes because they have no referent for the magnitudes involved. When people have a good "feel" for quantity, they estimate cardinal number magnitude linearly. Magnitude estimation errors can be explained by confusion about the structure of the decimal number system, particularly in terms of how powers of ten are related to one another. Indonesian children regularly use large currency units. This study investigated if they estimate long time periods accurately and if they estimate those time periods the same way they estimate analogous currency units. Thirty-nine children from a private International Baccalaureate school estimated temporal magnitudes up to 10,000,000,000 years in a two-part study. Artifacts children created were compared to theoretical model predictions previously used in number magnitude estimation studies as reported by Landy et al. (Cognitive Science 37:775-799, 2013). Over one third estimated the magnitude of time periods up to 10,000,000,000 years linearly, exceeding what would be expected based upon prior research with children this age who lack daily experience with large quantities. About half treated successive powers of ten as a count sequence instead of multiplicatively related when estimating magnitudes of time periods. Children generally estimated the magnitudes of long time periods and familiar, analogous currency units the same way. Implications for ways to improve the teaching and learning of this crosscutting concept/overarching idea are discussed.

  11. Trajectories of Symbolic and Nonsymbolic Magnitude Processing in the First Year of Formal Schooling.

    PubMed

    Matejko, Anna A; Ansari, Daniel

    2016-01-01

    Sensitivity to numerical magnitudes is thought to provide a foundation for higher-level mathematical skills such as calculation. It is still unclear how symbolic (e.g. Arabic digits) and nonsymbolic (e.g. Dots) magnitude systems develop and how the two formats relate to one another. Some theories propose that children learn the meaning of symbolic numbers by scaffolding them onto a pre-existing nonsymbolic system (Approximate Number System). Others suggest that symbolic and nonsymbolic magnitudes have distinct and non-overlapping representations. In the present study, we examine the developmental trajectories of symbolic and nonsymbolic magnitude processing skills and how they relate to each other in the first year of formal schooling when children are becoming more fluent with symbolic numbers. Thirty Grade 1 children completed symbolic and nonsymbolic magnitude processing tasks at three time points in Grade 1. We found that symbolic and nonsymbolic magnitude processing skills had distinct developmental trajectories, where symbolic magnitude processing was characterized by greater gains than nonsymbolic skills over the one-year period in Grade 1. We further found that the development of the two formats only related to one another in the first half of the school year where symbolic magnitude processing skills influenced later nonsymbolic skills. These findings indicate that symbolic and nonsymbolic abilities have different developmental trajectories and that the development of symbolic abilities is not strongly linked to nonsymbolic representations by Grade 1. These findings also suggest that the relationship between symbolic and nonsymbolic processing is not as unidirectional as previously thought. PMID:26930195

  12. Trajectories of Symbolic and Nonsymbolic Magnitude Processing in the First Year of Formal Schooling

    PubMed Central

    Matejko, Anna A.; Ansari, Daniel

    2016-01-01

    Sensitivity to numerical magnitudes is thought to provide a foundation for higher-level mathematical skills such as calculation. It is still unclear how symbolic (e.g. Arabic digits) and nonsymbolic (e.g. Dots) magnitude systems develop and how the two formats relate to one another. Some theories propose that children learn the meaning of symbolic numbers by scaffolding them onto a pre-existing nonsymbolic system (Approximate Number System). Others suggest that symbolic and nonsymbolic magnitudes have distinct and non-overlapping representations. In the present study, we examine the developmental trajectories of symbolic and nonsymbolic magnitude processing skills and how they relate to each other in the first year of formal schooling when children are becoming more fluent with symbolic numbers. Thirty Grade 1 children completed symbolic and nonsymbolic magnitude processing tasks at three time points in Grade 1. We found that symbolic and nonsymbolic magnitude processing skills had distinct developmental trajectories, where symbolic magnitude processing was characterized by greater gains than nonsymbolic skills over the one-year period in Grade 1. We further found that the development of the two formats only related to one another in the first half of the school year where symbolic magnitude processing skills influenced later nonsymbolic skills. These findings indicate that symbolic and nonsymbolic abilities have different developmental trajectories and that the development of symbolic abilities is not strongly linked to nonsymbolic representations by Grade 1. These findings also suggest that the relationship between symbolic and nonsymbolic processing is not as unidirectional as previously thought. PMID:26930195

  13. Method for measuring surface shear stress magnitude and direction using liquid crystal coatings

    NASA Technical Reports Server (NTRS)

    Reda, Daniel C. (Inventor)

    1995-01-01

    A method is provided for determining surface shear magnitude and direction at every point on a surface. The surface is covered with a shear stress sensitive liquid crystal coating and illuminated by white light from a normal direction. A video camera is positioned at an oblique angle above the surface to observe the color of the liquid crystal at that angle. The shear magnitude and direction are derived from the color information. A method of calibrating the device is also provided.

  14. The magnitude of the stomatal response to blue light : modulation by atmospheric humidity.

    PubMed

    Assmann, S M; Grantz, D A

    1990-06-01

    The effect of leaf-air vapor pressure difference (VPD) on the magnitude of the stomatal response to blue light was investigated in soybean (Glycine max) by administering blue light pulses (22 seconds by 120 micromoles per square meter per second) at different levels of VPD and temperature. At 20 degrees C and 25 degrees C, the magnitude of the integrated conductance response decreased with increasing VPD (0.4 to 2.6 kiloPascals), due to an earlier onset of stomatal closure that terminated the pulse response. In contrast, at 30 degrees C this magnitude increased with rising VPD (0.9 to 3.5 kiloPascals), due to an increasing maximum excursion of the conductance response despite the accelerated onset of stomatal closure. When the feedforward response of stomata to humidity caused steady state transpiration to decrease with increasing VPD, the magnitude of the pulse-induced conductance response correlated with VPD rather than with transpiration. This suggests that water relations or metabolite movements within epidermal rather than bulk leaf tissue interacted with guard cell photobiological properties in regulating the magnitude of the blue light response. VPD modulation of pulse magnitude could reduce water loss during stomatal responses to transient illumination in natural light environments. PMID:16667526

  15. Regional Variations of the ω-upper Bound Magnitude of GIII Distribution in the Iranian Plateau

    NASA Astrophysics Data System (ADS)

    Mohammadi, Hiwa; Bayrak, Yusuf

    2016-08-01

    The Iranian Plateau does not appear to be a single crustal block, but an assemblage of zones comprising the Alborz-Azerbaijan, Zagros, Kopeh-Dagh, Makran, and Central and East Iran. The Gumbel's III asymptotic distribution method (GIII) and maximum magnitude expected by Kijko-Sellevoll method is applied in order to check the potentiality of the each seismogenic zone in the Iranian Plateau for the future occurrence of maximum magnitude (Mmax). For this purpose, a homogeneous and complete seismicity database of the instrumental period during 1900-2012 is used in 29 seismogenic zones of the examined region. The spatial mapping of hazard parameters (upper bound magnitude (ω), most probable earthquake magnitude in next 100 years (M100) and maximum magnitude expected by maximum magnitude estimated by Kijko-Sellevoll method ( {M_{max }^{K - S}} ) reveals that Central and East Iran, Alborz and Azerbaijan, Kopeh-Dagh and SE Zagros are a dangerous place for the next occurrence of a large earthquake.

  16. Selective interference of grasp and space representations with number magnitude and serial order processing.

    PubMed

    van Dijck, Jean-Philippe; Fias, Wim; Andres, Michael

    2015-10-01

    It has been proposed that the metrics of space, time and other magnitudes relevant for action are coupled through a generalized magnitude system that also contribute to number representation. Several studies capitalized on stimulus-response compatibility effects to show that numbers map onto left-right representations and grasp representations as a function of their magnitude. However, the tasks typically used do not allow disentangling magnitude from serial order processing. Here, we devised a working memory (WM) task where participants had to remember random sequences of numbers and perform a precision/whole-hand grip (Experiment 1) or a uni-manual left/right button press (Experiment 2) in response to numbers presented during the retention interval. This task does allow differentiating the interference of number magnitude and serial order with each set of responses. Experiment 1 showed that precision grips were initiated faster than whole-hand grips in response to small numbers, irrespective of their serial position in WM. In contrast, Experiment 2 revealed an advantage of right over left button presses as serial position increased, without any influence of number magnitude. These findings demonstrate that grasping and left-right movements overlap with distinct dimensions of number processing. These findings are discussed in the light of different theories explaining the interactions between numbers, space and action.

  17. Detonation charge size versus coda magnitude relations in California and Nevada

    USGS Publications Warehouse

    Brocher, T.M.

    2003-01-01

    Magnitude-charge size relations have important uses in forensic seismology and are used in Comprehensive Nuclear-Test-Ban Treaty monitoring. I derive empirical magnitude versus detonation-charge-size relationships for 322 detonations located by permanent seismic networks in California and Nevada. These detonations, used in 41 different seismic refraction or network calibration experiments, ranged in yield (charge size) between 25 and 106 kg; coda magnitudes reported for them ranged from 0.5 to 3.9. Almost all represent simultaneous (single-fired) detonations of one or more boreholes. Repeated detonations at the same shotpoint suggest that the reported coda magnitudes are repeatable, on average, to within 0.1 magnitude unit. An empirical linear regression for these 322 detonations yields M = 0.31 + 0.50 log10(weight [kg]). The detonations compiled here demonstrate that the Khalturin et al. (1998) relationship, developed mainly for data from large chemical explosions but which fits data from nuclear blasts, can be used to estimate the minimum charge size for coda magnitudes between 0.5 and 3.9. Drilling, loading, and shooting logs indicate that the explosive specification, loading method, and effectiveness of tamp are the primary factors determining the efficiency of a detonation. These records indicate that locating a detonation within the water table is neither a necessary nor sufficient condition for an efficient shot.

  18. Bone strain magnitude is correlated with bone strain rate in tetrapods: implications for models of mechanotransduction

    PubMed Central

    Aiello, B. R.; Iriarte-Diaz, J.; Blob, R. W.; Butcher, M. T.; Carrano, M. T.; Espinoza, N. R.; Main, R. P.; Ross, C. F.

    2015-01-01

    Hypotheses suggest that structural integrity of vertebrate bones is maintained by controlling bone strain magnitude via adaptive modelling in response to mechanical stimuli. Increased tissue-level strain magnitude and rate have both been identified as potent stimuli leading to increased bone formation. Mechanotransduction models hypothesize that osteocytes sense bone deformation by detecting fluid flow-induced drag in the bone's lacunar–canalicular porosity. This model suggests that the osteocyte's intracellular response depends on fluid-flow rate, a product of bone strain rate and gradient, but does not provide a mechanism for detection of strain magnitude. Such a mechanism is necessary for bone modelling to adapt to loads, because strain magnitude is an important determinant of skeletal fracture. Using strain gauge data from the limb bones of amphibians, reptiles, birds and mammals, we identified strong correlations between strain rate and magnitude across clades employing diverse locomotor styles and degrees of rhythmicity. The breadth of our sample suggests that this pattern is likely to be a common feature of tetrapod bone loading. Moreover, finding that bone strain magnitude is encoded in strain rate at the tissue level is consistent with the hypothesis that it might be encoded in fluid-flow rate at the cellular level, facilitating bone adaptation via mechanotransduction. PMID:26063842

  19. Relatively high motivation for context-evoked reward produces the magnitude effect in rats.

    PubMed

    Yuki, Shoko; Okanoya, Kazuo

    2014-09-01

    Using a concurrent-chain schedule, we demonstrated the effect of absolute reinforcement (i.e., the magnitude effect) on choice behavior in rats. In general, animals' simultaneous choices conform to a relative reinforcement ratio between alternatives. However, studies in pigeons and rats have found that on a concurrent-chain schedule, the overall reinforcement ratio, or absolute amount, also influences choice. The effect of reinforcement amount has also been studied in inter-temporal choice situations, and this effect has been referred to as the magnitude effect. The magnitude effect has been observed in humans under various conditions, but little research has assessed it in animals (e.g., pigeons and rats). The present study confirmed the effect of reinforcement amount in rats during simultaneous and inter-temporal choice situations. We used a concurrent-chain procedure to examine the cause of the magnitude effect during inter-temporal choice. Our results suggest that rats can use differences in reinforcement amount as a contextual cue during choice, and the direction of the magnitude effect in rats might be similar to humans when using the present procedure. Furthermore, our results indicate that the magnitude effect was caused by the initial-link effect when the reinforcement amount was relatively small, while a loss aversion tendency was observed when the reinforcement amount changed within a session. The emergence of the initial-link effect and loss aversion suggests that rats make choices through cognitive processes predicted by prospect theory. PMID:25064376

  20. Subregions of the ventral striatum show preferential coding of reward magnitude and probability.

    PubMed

    Yacubian, Juliana; Sommer, Tobias; Schroeder, Katrin; Gläscher, Jan; Braus, Dieter F; Büchel, Christian

    2007-11-15

    As shown in non-human primate and human fMRI studies the probability and magnitude of anticipated rewards modulate activity in the mesolimbic dopaminergic system. Importantly, non-human primate data have revealed that single dopaminergic neurons code for both probability and magnitude of expected reward, suggesting an identical system. Using a guessing task that allowed the independent assessment of the factors probability and magnitude we were able to assess the impact of reward probability and magnitude in ventral striatal subregions in a large sample (n=98). We observed more anterior and lateral peak activation foci in the ventral striatum for reward probability and a more posterior and medial activation peak for reward magnitude, suggesting a functional segregation at the mesoscopic level. Importantly, this functional bias observed for the group average was also tested in each individual subject, allowing for proper random effects inference for the spatial dissociation. Taken together, our data point toward a functional dissociation of neuronal assemblies suggesting that certain populations of neurons are more sensitive to expected reward probability and other populations are more sensitive to reward magnitude. PMID:17889562

  1. Reinforcer magnitude affects delay discounting and influences effects of d-amphetamine in rats.

    PubMed

    Krebs, Christopher A; Reilly, William J; Anderson, Karen G

    2016-09-01

    Impulsive choice in humans can be altered by changing reinforcer magnitude; however, this effect has not been found in rats. Current levels of impulsive choice can also influence effects of d-amphetamine. This study used a within-subject assessment to determine if impulsive choice is sensitive to changes in reinforcer magnitude, and whether effects of d-amphetamine are related to current levels of impulsive choice. A discounting procedure in which choice was for a smaller reinforcer available immediately or a larger reinforcer available after a delay that increased within session was used. Reinforcer magnitude was manipulated between conditions and impulsive choice was quantified using area under the curve (AUC). In the Smaller-Magnitude (SM) Condition, choice was between one food pellet and three food pellets. In the Larger-Magnitude (LM) Condition, choice was between two food pellets and six food pellets. Impulsive choice was greater in the SM Condition compared to the LM Condition. Further, effects of d-amphetamine (0.1-1.8mg/kg) were related to differences in impulsive choice. d-Amphetamine increased impulsive choice in the LM Condition, but had no effect on impulsive choice in the SM Condition. Overall, these results show that impulsive choice in rats is sensitive to changes in reinforcer magnitude, and that effects of d-amphetamine are influenced by current levels of impulsive choice.

  2. Relatively high motivation for context-evoked reward produces the magnitude effect in rats.

    PubMed

    Yuki, Shoko; Okanoya, Kazuo

    2014-09-01

    Using a concurrent-chain schedule, we demonstrated the effect of absolute reinforcement (i.e., the magnitude effect) on choice behavior in rats. In general, animals' simultaneous choices conform to a relative reinforcement ratio between alternatives. However, studies in pigeons and rats have found that on a concurrent-chain schedule, the overall reinforcement ratio, or absolute amount, also influences choice. The effect of reinforcement amount has also been studied in inter-temporal choice situations, and this effect has been referred to as the magnitude effect. The magnitude effect has been observed in humans under various conditions, but little research has assessed it in animals (e.g., pigeons and rats). The present study confirmed the effect of reinforcement amount in rats during simultaneous and inter-temporal choice situations. We used a concurrent-chain procedure to examine the cause of the magnitude effect during inter-temporal choice. Our results suggest that rats can use differences in reinforcement amount as a contextual cue during choice, and the direction of the magnitude effect in rats might be similar to humans when using the present procedure. Furthermore, our results indicate that the magnitude effect was caused by the initial-link effect when the reinforcement amount was relatively small, while a loss aversion tendency was observed when the reinforcement amount changed within a session. The emergence of the initial-link effect and loss aversion suggests that rats make choices through cognitive processes predicted by prospect theory.

  3. Correlation between acceleration magnitude and ocular vestibular-evoked myogenic potential.

    PubMed

    Wang, Shou-Jen; Jaw, Fu-Shan; Young, Yi-Ho

    2012-05-10

    This study combined bone-conducted vibration (BCV) stimulation with triaxial accelerometry to correlate the acceleration magnitudes of BCV stimuli with ocular vestibular-evoked myogenic potential (oVEMP) test results. Fourteen healthy volunteers underwent oVEMP test using BCV stimuli with simultaneous monitoring the triaxial acceleration. All (100%) subjects exhibited clear oVEMPs in response to BCV stimuli from a vibrator. The lowest acceleration magnitudes for eliciting oVEMPs along the x-, y- and z-axes were 0.05±0.01 g, 0.16±0.08 g, and 0.04±0.01 g, respectively, exhibiting significantly higher acceleration magnitude along the y-axis than those along the x- and z-axes. In addition, significantly positive correlations were noted between the acceleration magnitude along each axis and the oVEMP amplitude. In conclusion, measuring the acceleration magnitude throughout oVEMP testing revealed a significant correlation between linear acceleration and oVEMP responses. Restated, increasing acceleration magnitude may have more synchronization of firing of vestibular afferents, resulting in more synchronized evoked potentials and greater oVEMP amplitude.

  4. The parietal cortex and the representation of time, space, number and other magnitudes.

    PubMed

    Bueti, Domenica; Walsh, Vincent

    2009-07-12

    The development of sub-disciplines within cognitive neuroscience follows common sense categories such as language, audition, action, memory, emotion and perception among others. There are also well-established research programmes into temporal perception, spatial perception and mathematical cognition that also reflect the subjective impression of how experience is constructed. There is of course no reason why the brain should respect these common sense, text book divisions and, here, we discuss the contention that generalized magnitude processing is a more accurate conceptual description of how the brain deals with information about time, space, number and other dimensions. The roots of the case for linking magnitudes are based on the use to which magnitude information is put (action), the way in which we learn about magnitudes (ontogeny), shared properties and locations of magnitude processing neurons, the effects of brain lesions and behavioural interference studies. Here, we assess this idea in the context of a theory of magnitude, which proposed common processing mechanisms of time, space, number and other dimensions.

  5. Self-motion magnitude estimation during linear oscillation - Changes with head orientation and following fatigue

    NASA Technical Reports Server (NTRS)

    Parker, D. E.; Wood, D. L.; Gulledge, W. L.; Goodrich, R. L.

    1979-01-01

    Two types of experiments concerning the estimated magnitude of self-motion during exposure to linear oscillation on a parallel swing are described in this paper. Experiment I examined changes in magnitude estimation as a function of variation of the subject's head orientation, and Experiments II a, II b, and II c assessed changes in magnitude estimation performance following exposure to sustained, 'intense' linear oscillation (fatigue-inducting stimulation). The subjects' performance was summarized employing Stevens' power law R = k x S to the nth, where R is perceived self-motion magnitude, k is a constant, S is amplitude of linear oscillation, and n is an exponent). The results of Experiment I indicated that the exponents, n, for the magnitude estimation functions varied with head orientation and were greatest when the head was oriented 135 deg off the vertical. In Experiments II a-c, the magnitude estimation function exponents were increased following fatigue. Both types of experiments suggest ways in which the vestibular system's contribution to a spatial orientation perceptual system may vary. This variability may be a contributing factor to the development of pilot/astronaut disorientation and may also be implicated in the occurrence of motion sickness.

  6. Reinforcer magnitude affects delay discounting and influences effects of d-amphetamine in rats.

    PubMed

    Krebs, Christopher A; Reilly, William J; Anderson, Karen G

    2016-09-01

    Impulsive choice in humans can be altered by changing reinforcer magnitude; however, this effect has not been found in rats. Current levels of impulsive choice can also influence effects of d-amphetamine. This study used a within-subject assessment to determine if impulsive choice is sensitive to changes in reinforcer magnitude, and whether effects of d-amphetamine are related to current levels of impulsive choice. A discounting procedure in which choice was for a smaller reinforcer available immediately or a larger reinforcer available after a delay that increased within session was used. Reinforcer magnitude was manipulated between conditions and impulsive choice was quantified using area under the curve (AUC). In the Smaller-Magnitude (SM) Condition, choice was between one food pellet and three food pellets. In the Larger-Magnitude (LM) Condition, choice was between two food pellets and six food pellets. Impulsive choice was greater in the SM Condition compared to the LM Condition. Further, effects of d-amphetamine (0.1-1.8mg/kg) were related to differences in impulsive choice. d-Amphetamine increased impulsive choice in the LM Condition, but had no effect on impulsive choice in the SM Condition. Overall, these results show that impulsive choice in rats is sensitive to changes in reinforcer magnitude, and that effects of d-amphetamine are influenced by current levels of impulsive choice. PMID:27418423

  7. Estrategia innovadora enfocada en parejas del mismo sexo para disminuir la infección del VIH en hombres Latinos

    PubMed Central

    Martinez, Omar; Wu, Elwin; Sandfort, Theo; Shultz, Andrew Z.; Capote, Jonathan; Chávez, Silvia; Moya, Eva; Dodge, Brian; Morales, Gabriel; Porras, Antonio; Ovejero, Hugo

    2014-01-01

    Resumen El VIH es un problema de salud importante dentro de la comunidad latina de los Estados Unidos. Gracias a los esfuerzos de prevención, los niveles de contagio entre los latinos se han mantenido estables por más de una década. Sin embargo, esta población sigue siendo afectada a niveles muy altos, en particular entre hombres que tienen sexo con hombres (HSH), de origen latino y que hablan principalmente el idioma español. Existen varios factores que contribuyen a la transmisión del VIH entre esta población, como son: el uso de drogas; la violencia dentro de la pareja; la presencia de infecciones de transmisión sexual; relaciones sexuales sin protección, dentro y fuera de la pareja; el evadir la búsqueda de recursos (prueba y tratamiento adecuado) por temor a ser discriminado o por su estatus migratorio; la escasez de recursos económicos o estado de pobreza y los patrones relacionados a la migración. En particular, Investigaciones Epidemiológicas de Comportamientos han determinado: cómo algunas dinámicas en parejas están directamente asociadas a los comportamientos sexuales de riesgos. En consecuencia, es necesaria mayor investigación para identificar esas dinámicas, y a su vez, realizar intervenciones dirigidas a la reducción de conductas de riesgo enfocadas en parejas de hombres del mismo sexo. En este escrito, se describe la importancia del uso de las relaciones de pareja como estrategia en la reducción de la trasmisión del VIH/SIDA en HSH de origen latino y que hablan principalmente el idioma español en los Estados Unidos. PMID:25580466

  8. Problemas del Lenguaje Espanol en la Prensa: El Castellano, Esta Lengua Enferma (Problems of the Spanish Language in the Press: Castillian, That Closed-In Language)

    ERIC Educational Resources Information Center

    Quijada, Carlos Alonso

    1977-01-01

    Learned academies deplore the deterioration of Castillian Spanish due to foreign contamination. They ignore the real source of the problem within Spain itself where everyone speaks the language badly except those in the remote towns and a few intellectuals. A ray of hope comes from the Americans. (Text is in Spanish.) (AMH)

  9. Temas y Problemas del idioma espanol en la prensa: El lenguaje, arma peligrosa (Themes and Problems of the Spanish Language in the Press: Language, a Dangerous Weapon).

    ERIC Educational Resources Information Center

    de Senillosa, Antonio

    1979-01-01

    Discusses the important role that language has in our society and compares human communication to animal group communication. Gives specific examples of corruption in the Spanish language today. (NCR)

  10. Earthquake rate and magnitude distributions of great earthquakes for use in global forecasts

    NASA Astrophysics Data System (ADS)

    Kagan, Yan Y.; Jackson, David D.

    2016-07-01

    We have obtained new results in the statistical analysis of global earthquake catalogues with special attention to the largest earthquakes, and we examined the statistical behaviour of earthquake rate variations. These results can serve as an input for updating our recent earthquake forecast, known as the `Global Earthquake Activity Rate 1' model (GEAR1), which is based on past earthquakes and geodetic strain rates. The GEAR1 forecast is expressed as the rate density of all earthquakes above magnitude 5.8 within 70 km of sea level everywhere on earth at 0.1 × 0.1 degree resolution, and it is currently being tested by the Collaboratory for Study of Earthquake Predictability. The seismic component of the present model is based on a smoothed version of the Global Centroid Moment Tensor (GCMT) catalogue from 1977 through 2013. The tectonic component is based on the Global Strain Rate Map, a `General Earthquake Model' (GEM) product. The forecast was optimized to fit the GCMT data from 2005 through 2012, but it also fit well the earthquake locations from 1918 to 1976 reported in the International Seismological Centre-Global Earthquake Model (ISC-GEM) global catalogue of instrumental and pre-instrumental magnitude determinations. We have improved the recent forecast by optimizing the treatment of larger magnitudes and including a longer duration (1918-2011) ISC-GEM catalogue of large earthquakes to estimate smoothed seismicity. We revised our estimates of upper magnitude limits, described as corner magnitudes, based on the massive earthquakes since 2004 and the seismic moment conservation principle. The new corner magnitude estimates are somewhat larger than but consistent with our previous estimates. For major subduction zones we find the best estimates of corner magnitude to be in the range 8.9 to 9.6 and consistent with a uniform average of 9.35. Statistical estimates tend to grow with time as larger earthquakes occur. However, by using the moment conservation

  11. Analysis of Scaling Parameters of Event Magnitudes by Fluid Injections in Reservoirs

    NASA Astrophysics Data System (ADS)

    Dinske, Carsten; Krüger, Oliver; Shapiro, Serge

    2014-05-01

    We continue to elaborate scaling parameters of observed frequency-magnitude distributions of injection-induced seismicity. In addition to pumped fluid mass, b-value and seismogenic index (Shapiro et al., 2010, Dinske and Shapiro, 2013), one more scaling was recognised by the analysis of the induced event magnitudes. A frequently observed under-representation of events with larger magnitudes in comparison with the Gutenberg-Richter relation is explained by the geometry and the dimensions of the hydraulically stimulated rock volume (Shapiro et al., 2011, 2013). This under-representation, however, introduces a bias in b-value estimations which then should be considered as an apparent and transient b-value depending on the size of the perturbed rock volume. We study in detail in which way the seismogenic index estimate is affected by the apparent b-value. For this purpose, we compare b-value and seismogenic index estimates using two different approaches. First, we perform standard Gutenberg-Richter power-law fitting and second, we apply frequency-magnitude lower bound probability fitting as proposed by Shapiro et al. (2013). The latter takes into account the finite size of the perturbed rock volume. Our result reveals that the smaller is the perturbed rock volume the larger are the deviations between the two sets of derived parameters. It means that the magnitude statistics of the induced events is most affected for low injection volumes and/or short injection times. At sufficiently large stimulated volumes both fitting approaches provide comparable b-value and seismogenic index estimates. In particular, the b-value is then in the range of b-values universally obtained for tectonic earthquakes (i.e., 0.8 - 1.2). Based on our findings, we introduce the specific magnitude which is a seismotectonic characteristic for a reservoir location. Defined as the ratio of seismogenic index and b-value, the specific magnitude is found to be a magnitude scaling parameter which is

  12. Intensity, magnitude, location and attenuation in India for felt earthquakes since 1762

    USGS Publications Warehouse

    Szeliga, Walter; Hough, Susan; Martin, Stacey; Bilham, Roger

    2010-01-01

    A comprehensive, consistently interpreted new catalog of felt intensities for India (Martin and Szeliga, 2010, this issue) includes intensities for 570 earthquakes; instrumental magnitudes and locations are available for 100 of these events. We use the intensity values for 29 of the instrumentally recorded events to develop new intensity versus attenuation relations for the Indian subcontinent and the Himalayan region. We then use these relations to determine the locations and magnitudes of 234 historical events, using the method of Bakun and Wentworth (1997). For the remaining 336 events, intensity distributions are too sparse to determine magnitude or location. We evaluate magnitude and location accuracy of newly located events by comparing the instrumental- with the intensity-derived location for 29 calibration events, for which more than 15 intensity observations are available. With few exceptions, most intensity-derived locations lie within a fault length of the instrumentally determined location. For events in which the azimuthal distribution of intensities is limited, we conclude that the formal error bounds from the regression of Bakun and Wentworth (1997) do not reflect the true uncertainties. We also find that the regression underestimates the uncertainties of the location and magnitude of the 1819 Allah Bund earthquake, for which a location has been inferred from mapped surface deformation. Comparing our inferred attenuation relations to those developed for other regions, we find that attenuation for Himalayan events is comparable to intensity attenuation in California (Bakun and Wentworth, 1997), while intensity attenuation for cratonic events is higher than intensity attenuation reported for central/eastern North America (Bakun et al., 2003). Further, we present evidence that intensities of intraplate earthquakes have a nonlinear dependence on magnitude such that attenuation relations based largely on small-to-moderate earthquakes may significantly

  13. Intensity, magnitude, location, and attenuation in India for felt earthquakes since 1762

    USGS Publications Warehouse

    Szeliga, W.; Hough, S.; Martin, S.; Bilham, R.

    2010-01-01

    A comprehensive, consistently interpreted new catalog of felt intensities for India (Martin and Szeliga, 2010, this issue) includes intensities for 570 earth-quakes; instrumental magnitudes and locations are available for 100 of these events. We use the intensity values for 29 of the instrumentally recorded events to develop new intensity versus attenuation relations for the Indian subcontinent and the Himalayan region. We then use these relations to determine the locations and magnitudes of 234 historical events, using the method of Bakun and Wentworth (1997). For the remaining 336 events, intensity distributions are too sparse to determine magnitude or location. We evaluate magnitude and location accuracy of newly located events by comparing the instrumental-with the intensity-derived location for 29 calibration events, for which more than 15 intensity observations are available. With few exceptions, most intensity-derived locations lie within a fault length of the instrumentally determined location. For events in which the azimuthal distribution of intensities is limited, we conclude that the formal error bounds from the regression of Bakun and Wentworth (1997) do not reflect the true uncertainties. We also find that the regression underestimates the uncertainties of the location and magnitude of the 1819 Allah Bund earthquake, for which a location has been inferred from mapped surface deformation. Comparing our inferred attenuation relations to those developed for other regions, we find that attenuation for Himalayan events is comparable to intensity attenuation in California (Bakun and Wentworth, 1997), while intensity attenuation for cratonic events is higher than intensity attenuation reported for central/eastern North America (Bakun et al., 2003). Further, we present evidence that intensities of intraplate earth-quakes have a nonlinear dependence on magnitude such that attenuation relations based largely on small-to-moderate earthquakes may significantly

  14. Heterogeneous in situ stress magnitudes due to the presence of weak natural discontinuities in granitic rocks

    NASA Astrophysics Data System (ADS)

    Chang, Chandong; Jo, Yeonguk

    2015-11-01

    Two field examples of hydraulic fracturing stress measurements are reported, in which the determined stress magnitudes exhibit severe variations with depth. The stress measurements were conducted in vertical boreholes drilled in granites in two different locations in South Korea. Several isolated intervals of intact rocks in the boreholes were vertically fractured by injecting water. The magnitudes of the minimum horizontal principal compressive stress (Shmin) were determined from shut-in pressures. The magnitudes of the maximum horizontal principal compressive stress (SHmax) were estimated based on the Kirsch equation using tensile strengths determined from hollow cylinder tests and Brazilian tests, in which pressurization-rate effects on tensile strength were taken into account. The stress states in both locations are in reverse-faulting stress regimes. The magnitudes of SHmax are generally within a stress range defined by frictional limits of favorably oriented fractures having frictional coefficients of 0.6 and 1.0. However, SHmax magnitudes do not increase linearly with depth, but rather scatter quite severely. It is noted that near the depths where the measured stresses are relatively low, natural discontinuities with wide apertures containing weak filling material exist, whereas near the depths of high stress, such wide discontinuities are scarce. Wide aperture discontinuities are predominantly oriented such that their slip tendency is high under the given stress conditions, meaning that if excessive shear stress is exerted, the weak discontinuities would slip to release the excessive stress. Such local processes would restrict SHmax magnitudes within values that can only be sustained by the shear strengths of the discontinuities, leading to severe variations of SHmax with depth. This result suggests that stress magnitudes are controlled quite locally by the frictional property of natural discontinuities, and that the stress state in granitic rock might be

  15. Global survey of star clusters in the Milky Way. V. Integrated JHKS magnitudes and luminosity functions

    NASA Astrophysics Data System (ADS)

    Kharchenko, N. V.; Piskunov, A. E.; Schilbach, E.; Röser, S.; Scholz, R.-D.

    2016-01-01

    Aims: In this study we determine absolute integrated magnitudes in the J,H,KS passbands for Galactic star clusters from the Milky Way Star Clusters survey. In the wide solar neighbourhood, we derive the open cluster luminosity function (CLF) for different cluster ages. Methods: The integrated magnitudes are based on uniform cluster membership derived from the 2MAst catalogue (a merger of the PPMXL and 2MASS) and are computed by summing up the individual luminosities of the most reliable cluster members. We discuss two different techniques of constructing the CLF, a magnitude-limited and a distance-limited approach. Results: Absolute J,H,KS integrated magnitudes are obtained for 3061 open clusters, and 147 globular clusters. The integrated magnitudes and colours are accurate to about 0.8 and 0.2 mag, respectively. Based on the sample of open clusters we construct the general cluster luminosity function in the solar neighbourhood in the three passbands. In each passband the CLF shows a linear part covering a range of 6 to 7 mag at the bright end. The CLFs reach their maxima at an absolute magnitude of -2 mag, then drop by one order of magnitude. During cluster evolution, the CLF changes its slope within tight, but well-defined limits. The CLF of the youngest clusters has a steep slope of about 0.4 at bright magnitudes and a quasi-flat portion for faint clusters. For the oldest population, we find a flatter function with a slope of about 0.2. The CLFs at Galactocentric radii smaller than that of the solar circle differ from those in the direction of the Galactic anti-centre. The CLF in the inner area is flatter and the cluster surface density higher than the local one. In contrast, the CLF is somewhat steeper than the local one in the outer disk, and the surface density is lower. The corresponding catalogue of integrated magnitudes is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc

  16. Constraining stress magnitudes using petroleum exploration data in the Cooper Eromanga Basins, Australia

    NASA Astrophysics Data System (ADS)

    Reynolds, Scott D.; Mildren, Scott D.; Hillis, Richard R.; Meyer, Jeremy J.

    2006-03-01

    The magnitude of the in situ stresses in the Cooper-Eromanga Basins have been determined using an extensive petroleum exploration database from over 40 years of drilling. The magnitude of the vertical stress ( Sv) was calculated based on density and velocity checkshot data in 24 wells. Upper and lower bound values of the vertical stress magnitude are approximated by Sv = (14.39 × Z) 1.12 and Sv = (11.67 × Z) 1.15 functions respectively (where Z is depth in km and Sv is in MPa). Leak-off test data from the two basins constrain the lower bound estimate for the minimum horizontal stress ( Shmin) magnitude to 15.5 MPa/km. Closure pressures from a large number of minifrac tests indicate considerable scatter in the minimum horizontal stress magnitude, with values approaching the magnitude of the vertical stress in some areas. The magnitude of the maximum horizontal stress ( SHmax) was constrained by the frictional limits to stress beyond which faulting occurs and by the presence of drilling-induced tensile fractures in some wells. The maximum horizontal stress magnitude can only be loosely constrained regionally using frictional limits, due to the variability of both the minimum horizontal stress and vertical stress estimates. However, the maximum horizontal stress and thus the full stress tensor can be better constrained at individual well locations, as demonstrated in Bulyeroo-1 and Dullingari North-8, where the necessary data (i.e. image logs, minifrac tests and density logs) are available. The stress magnitudes determined indicate a predominantly strike-slip fault stress regime ( SHmax > Sv > Shmin) at a depth of between 1 and 3 km in the Cooper-Eromanga Basins. However, some areas of the basin are transitional between strike-slip and reverse fault stress regimes ( SHmax > Sv ≈ Shmin). Large differential stresses in the Cooper-Eromanga Basins indicate a high upper crustal strength for the region, consistent with other intraplate regions. We propose that the in

  17. CONTAMINACIÓN AMBIENTAL, VARIABILIDAD CLIMÁTICA Y CAMBIO CLIMÁTICO: UNA REVISIÓN DEL IMPACTO EN LA SALUD DE LA POBLACIÓN PERUANA

    PubMed Central

    Gonzales, Gustavo F.; Zevallos, Alisson; Gonzales-Castañeda, Cynthia; Nuñez, Denisse; Gastañaga, Carmen; Cabezas, César; Naeher, Luke; Levy, Karen; Steenland, Kyle

    2015-01-01

    RESUMEN El presente artículo es una revisión sobre la contaminación del agua, el aire y el efecto del cambio climático en la salud de la población peruana. Uno de los principales contaminantes del aire es el material particulado menor de 2,5 μ (PM 2,5), en la ciudad de Lima, anualmente 2300 muertes prematuras son atribuibles a este contaminante. Otro problema es la contaminación del aire domiciliario por el uso de cocinas con combustible de biomasa, donde la exposición excesiva a PM 2,5 dentro de las casas es responsable de aproximadamente 3000 muertes prematuras anuales entre adultos, con otro número desconocido de muertes entre niños debido a infecciones respiratorias. La contaminación del agua tiene como principales causas los desagües vertidos directamente a los ríos, minerales (arsénico) de varias fuentes, y fallas de las plantas de tratamiento. En el Perú, el cambio climático puede impactar en la frecuencia y severidad del fenómeno de El Niño oscilación del sur (ENSO) que se ha asociado con un incremento en los casos de enfermedades como cólera, malaria y dengue. El cambio climático incrementa la temperatura y puede extender las áreas afectadas por enfermedades transmitidas por vectores, además de tener efecto en la disponibilidad del agua y en la contaminación del aire. En conclusión, el Perú, pasa por una transición de factores de riesgo ambientales, donde coexisten riesgos tradicionales y modernos, y persisten los problemas infecciosos y crónicos, algunos de los cuales se asocian con problemas de contaminación de agua y de aire. PMID:25418656

  18. The effects of sound level and vibration magnitude on the relative discomfort of noise and vibration.

    PubMed

    Huang, Yu; Griffin, Michael J

    2012-06-01

    The relative discomfort caused by noise and vibration, how this depends on the level of noise and the magnitude of vibration, and whether the noise and vibration are presented simultaneously or sequentially has been investigated in a laboratory study with 20 subjects. Noise and vertical vibration were reproduced with all 49 combinations of 7 levels of noise and 7 magnitudes of vibration to allow the discomfort caused by one of the stimuli to be judged relative to the other stimulus using magnitude estimation. In four sessions, subjects judged noise relative to vibration and vibration relative to noise, with both simultaneous and sequential presentations of the stimuli. The equivalence of noise and vibration was not greatly dependent on whether the stimuli were simultaneous or sequential, but highly dependent on whether noise was judged relative to vibration or vibration was judged relative to noise. When judging noise, higher magnitude vibrations appeared to mask the discomfort caused by low levels of noise. When judging vibration, higher level noises appeared to mask the discomfort caused by low magnitudes of vibration. The judgment of vibration discomfort was more influenced by noise than the judgment of noise discomfort was influenced by vibration.

  19. A General Method to Estimate Earthquake Moment and Magnitude using Regional Phase Amplitudes

    SciTech Connect

    Pasyanos, M E

    2009-11-19

    This paper presents a general method of estimating earthquake magnitude using regional phase amplitudes, called regional M{sub o} or regional M{sub w}. Conceptually, this method uses an earthquake source model along with an attenuation model and geometrical spreading which accounts for the propagation to utilize regional phase amplitudes of any phase and frequency. Amplitudes are corrected to yield a source term from which one can estimate the seismic moment. Moment magnitudes can then be reliably determined with sets of observed phase amplitudes rather than predetermined ones, and afterwards averaged to robustly determine this parameter. We first examine in detail several events to demonstrate the methodology. We then look at various ensembles of phases and frequencies, and compare results to existing regional methods. We find regional M{sub o} to be a stable estimator of earthquake size that has several advantages over other methods. Because of its versatility, it is applicable to many more events, particularly smaller events. We make moment estimates for earthquakes ranging from magnitude 2 to as large as 7. Even with diverse input amplitude sources, we find magnitude estimates to be more robust than typical magnitudes and existing regional methods and might be tuned further to improve upon them. The method yields a more meaningful quantity of seismic moment, which can be recast as M{sub w}. Lastly, it is applied here to the Middle East region using an existing calibration model, but it would be easy to transport to any region with suitable attenuation calibration.

  20. Haptic perception of force magnitude and its relation to postural arm dynamics in 3D.

    PubMed

    van Beek, Femke E; Bergmann Tiest, Wouter M; Mugge, Winfred; Kappers, Astrid M L

    2015-12-08

    In a previous study, we found the perception of force magnitude to be anisotropic in the horizontal plane. In the current study, we investigated this anisotropy in three dimensional space. In addition, we tested our previous hypothesis that the perceptual anisotropy was directly related to anisotropies in arm dynamics. In experiment 1, static force magnitude perception was studied using a free magnitude estimation paradigm. This experiment revealed a significant and consistent anisotropy in force magnitude perception, with forces exerted perpendicular to the line between hand and shoulder being perceived as 50% larger than forces exerted along this line. In experiment 2, postural arm dynamics were measured using stochastic position perturbations exerted by a haptic device and quantified through system identification. By fitting a mass-damper-spring model to the data, the stiffness, damping and inertia parameters could be characterized in all the directions in which perception was also measured. These results show that none of the arm dynamics parameters were oriented either exactly perpendicular or parallel to the perceptual anisotropy. This means that endpoint stiffness, damping or inertia alone cannot explain the consistent anisotropy in force magnitude perception.

  1. The UBV Color Evolution of Classical Novae. II. Color-Magnitude Diagram

    NASA Astrophysics Data System (ADS)

    Hachisu, Izumi; Kato, Mariko

    2016-04-01

    We have examined the outburst tracks of 40 novae in the color-magnitude diagram (intrinsic B - V color versus absolute V magnitude). After reaching the optical maximum, each nova generally evolves toward blue from the upper right to the lower left and then turns back toward the right. The 40 tracks are categorized into one of six templates: very fast nova V1500 Cyg fast novae V1668 Cyg, V1974 Cyg, and LV Vul moderately fast nova FH Ser and very slow nova PU Vul. These templates are located from the left (blue) to the right (red) in this order, depending on the envelope mass and nova speed class. A bluer nova has a less massive envelope and faster nova speed class. In novae with multiple peaks, the track of the first decay is more red than that of the second (or third) decay, because a large part of the envelope mass had already been ejected during the first peak. Thus, our newly obtained tracks in the color-magnitude diagram provide useful information to understand the physics of classical novae. We also found that the absolute magnitude at the beginning of the nebular phase is almost similar among various novae. We are able to determine the absolute magnitude (or distance modulus) by fitting the track of a target nova to the same classification of a nova with a known distance. This method for determining nova distance has been applied to some recurrent novae, and their distances have been recalculated.

  2. Multi-objective control of nonlinear boiler-turbine dynamics with actuator magnitude and rate constraints.

    PubMed

    Chen, Pang-Chia

    2013-01-01

    This paper investigates multi-objective controller design approaches for nonlinear boiler-turbine dynamics subject to actuator magnitude and rate constraints. System nonlinearity is handled by a suitable linear parameter varying system representation with drum pressure as the system varying parameter. Variation of the drum pressure is represented by suitable norm-bounded uncertainty and affine dependence on system matrices. Based on linear matrix inequality algorithms, the magnitude and rate constraints on the actuator and the deviations of fluid density and water level are formulated while the tracking abilities on the drum pressure and power output are optimized. Variation ranges of drum pressure and magnitude tracking commands are used as controller design parameters, determined according to the boiler-turbine's operation range.

  3. Outcome probability versus magnitude: when waiting benefits one at the cost of the other.

    PubMed

    Young, Michael E; Webb, Tara L; Rung, Jillian M; McCoy, Anthony W

    2014-01-01

    Using a continuous impulsivity and risk platform (CIRP) that was constructed using a video game engine, choice was assessed under conditions in which waiting produced a continuously increasing probability of an outcome with a continuously decreasing magnitude (Experiment 1) or a continuously increasing magnitude of an outcome with a continuously decreasing probability (Experiment 2). Performance in both experiments reflected a greater desire for a higher probability even though the corresponding wait times produced substantive decreases in overall performance. These tendencies are considered to principally reflect hyperbolic discounting of probability, power discounting of magnitude, and the mathematical consequences of different response rates. Behavior in the CIRP is compared and contrasted with that in the Balloon Analogue Risk Task (BART).

  4. Vector Quantization of Harmonic Magnitudes in Speech Coding Applications—A Survey and New Technique

    NASA Astrophysics Data System (ADS)

    Chu, Wai C.

    2004-12-01

    A harmonic coder extracts the harmonic components of a signal and represents them efficiently using a few parameters. The principles of harmonic coding have become quite successful and several standardized speech and audio coders are based on it. One of the key issues in harmonic coder design is in the quantization of harmonic magnitudes, where many propositions have appeared in the literature. The objective of this paper is to provide a survey of the various techniques that have appeared in the literature for vector quantization of harmonic magnitudes, with emphasis on those adopted by the major speech coding standards; these include constant magnitude approximation, partial quantization, dimension conversion, and variable-dimension vector quantization (VDVQ). In addition, a refined VDVQ technique is proposed where experimental data are provided to demonstrate its effectiveness.

  5. Magnitude Effects for Experienced Rewards at Short Delays in the Escalating Interest Task

    PubMed Central

    Young, Michael E.; Webb, Tara L.; Sutherland, Steven C.; Jacobs, Eric A.

    2012-01-01

    A first-person shooter video game was adapted for the study of choice between smaller sooner and larger later rewards. Participants chose when to fire a weapon that increased in damage potential over a short interval. When the delay to maximum damage was shorter (5 – 8 s), people showed greater sensitivity to the consequences of their choices than when the delay was longer (17 – 20 s). Participants also evidenced a magnitude effect by waiting proportionally longer when the damage magnitudes were doubled for all rewards. The experiment replicated the standard magnitude effect with this new video game preparation over time scales similar to those typically used in nonhuman animal studies and without complications due to satiation or cost. PMID:23188742

  6. Change magnitude does not guide attention in an object change detection task.

    PubMed

    Favelle, Simone K; Palmisano, Stephen

    2015-01-01

    Investigations of change detection consistently reveal an effect of change magnitude: changes involving more object parts are detected more easily than those involving fewer parts. Whether large changes improve detection by providing stronger preattentive signals to the change location is subject to debate. We report a cued object change detection experiment that tested this hypothesis while controlling for stimulus familiarity, semantic knowledge, and change type (addition versus deletion). We found strong magnitude effects regardless of whether trials were validly or invalidly cued. The size of the cueing effects, which were exhibited for all the change magnitudes examined, did not decrease with the number of parts changing. These findings provide little support for a preattentive guidance hypothesis and instead support the thesis that change detection requires attention.

  7. Observations on the magnitude-frequency distribution of Earth-crossing asteroids

    NASA Technical Reports Server (NTRS)

    Shoemaker, Eugene M.; Shoemaker, Carolyn S.

    1987-01-01

    During the past decade, discovery of Earth-crossing asteroids has continued at the pace of several per year; the total number of known Earth crossers reached 70 as of September, 1986. The sample of discovered Earth crossers has become large enough to provide a fairly strong statistical basis for calculations of mean probabilities of asteroid collision with the Earth, the Moon, and Venus. It is also now large enough to begin to address the more difficult question of the magnitude-frequency distribution and size distribution of the Earth-crossing asteroids. Absolute V magnitude, H, was derived from reported magnitudes for each Earth crosser on the basis of a standard algorithm that utilizes a physically realistic phase function. The derived values of H range from 12.88 for (1627) Ivar to 21.6 for the Palomar-Leiden object 6344, which is the faintest and smallest asteroid discovered.

  8. Deformation mechanisms of bent Si nanowires governed by the sign and magnitude of strain

    NASA Astrophysics Data System (ADS)

    Wang, Lihua; Kong, Deli; Xin, Tianjiao; Shu, Xinyu; Zheng, Kun; Xiao, Lirong; Sha, Xuechao; Lu, Yan; Zhang, Ze; Han, Xiaodong; Zou, Jin

    2016-04-01

    In this study, the deformation mechanisms of bent Si nanowires are investigated at the atomic scale with bending strain up to 12.8%. The sign and magnitude of the applied strain are found to govern their deformation mechanisms, in which the dislocation types (full or partial dislocations) can be affected by the sign (tensile or compressive) and magnitude of the applied strain. In the early stages of bending, plastic deformation is controlled by 60° full dislocations. As the bending increases, Lomer dislocations can be frequently observed. When the strain increases to a significant level, 90° partial dislocations induced from the tensile surfaces of the bent nanowires are observed. This study provides a deeper understanding of the effect of the sign and magnitude of the bending strain on the deformation mechanisms in bent Si nanowires.

  9. Symbolic Numerical Magnitude Processing Is as Important to Arithmetic as Phonological Awareness Is to Reading.

    PubMed

    Vanbinst, Kiran; Ansari, Daniel; Ghesquière, Pol; De Smedt, Bert

    2016-01-01

    In this article, we tested, using a 1-year longitudinal design, whether symbolic numerical magnitude processing or children's numerical representation of Arabic digits, is as important to arithmetic as phonological awareness is to reading. Children completed measures of symbolic comparison, phonological awareness, arithmetic, reading at the start of third grade and the latter two were retested at the start of fourth grade. Cross-sectional and longitudinal correlations indicated that symbolic comparison was a powerful domain-specific predictor of arithmetic and that phonological awareness was a unique predictor of reading. Crucially, the strength of these independent associations was not significantly different. This indicates that symbolic numerical magnitude processing is as important to arithmetic development as phonological awareness is to reading and suggests that symbolic numerical magnitude processing is a good candidate for screening children at risk for developing mathematical difficulties. PMID:26942935

  10. No evidence of magnitude clustering in an aftershock sequence of nano- and picoseismicity.

    PubMed

    Davidsen, Jörn; Kwiatek, Grzegorz; Dresen, Georg

    2012-01-20

    One of the hallmarks of our current understanding of seismicity as highlighted by the epidemic-type-aftershock sequence model is that the magnitudes of earthquakes are independent of one another and can be considered as randomly drawn from the Gutenberg-Richter distribution. This assumption forms the basis of many approaches for forecasting seismicity rates and hazard assessment. Recently, it has been suggested that the assumption of independent magnitudes is not valid. It was subsequently argued that this conclusion was not supported by the original earthquake data from California. One of the main challenges is the lack of completeness of earthquake catalogs. Here, we study an aftershock sequence of nano- and picoseismicity as observed at the Mponeng mine, for which the issue of incompleteness is much less pronounced. We show that this sequence does not exhibit any significant evidence of magnitude correlations.

  11. The role of parity, physical size, and magnitude in numerical cognition: the SNARC effect revisited.

    PubMed

    Fitousi, Daniel; Shaki, Samuel; Algom, Daniel

    2009-01-01

    People indicate the physical size or the parity status of small numbers faster by a left-hand key and those of larger numbers by a right-hand key. Because magnitude information is not required for successful performance in these tasks, the presence of a number-space association (the SNARC effect) has been taken to indicate the automatic activation of numerical magnitude in all tasks with numerals. In order to test this account, in a series of five experiments, we derived two consensual markers of automatic activation of irrelevant numerical magnitude, the size congruity effect (for judgments of physical size), and the Garner effect (for judgments of parity). Both markers were found independent of the SNARC effect. Consequently, we question the traditional explanation of the SNARC effect and offer an alternative account in terms of a highly overlearned stimulus-response loop.

  12. Variations of Magnitude and Ionization Along the Traces of the Same Meteors

    NASA Astrophysics Data System (ADS)

    Narziev, Mirhusen

    2016-07-01

    Using the results of simultaneous television and basic radar observations of meteors from points 4-5, received during the periods of activity of the main annual meteor showers α - Kaprikornis, δ - Akvarids, Geminids, Quadrantids and Orionids in 1979 in GisAO, the variation of magnitude and linear electronic density along a traces of the same meteors were studied. It was determined that for meteors with velocities of 23-69 km/c the course of variation of magnitude and linear electronic density along the traces of the same meteors were fairly coordinated among themselves. The received results are compared with the similar data received for weaker meteors in Harward (Illinois). It is concluded that the difference between radar-tracking and photographic magnitude depends on the speed of meteors.

  13. Symbolic Numerical Magnitude Processing Is as Important to Arithmetic as Phonological Awareness Is to Reading

    PubMed Central

    Vanbinst, Kiran; Ansari, Daniel; Ghesquière, Pol; De Smedt, Bert

    2016-01-01

    In this article, we tested, using a 1-year longitudinal design, whether symbolic numerical magnitude processing or children’s numerical representation of Arabic digits, is as important to arithmetic as phonological awareness is to reading. Children completed measures of symbolic comparison, phonological awareness, arithmetic, reading at the start of third grade and the latter two were retested at the start of fourth grade. Cross-sectional and longitudinal correlations indicated that symbolic comparison was a powerful domain-specific predictor of arithmetic and that phonological awareness was a unique predictor of reading. Crucially, the strength of these independent associations was not significantly different. This indicates that symbolic numerical magnitude processing is as important to arithmetic development as phonological awareness is to reading and suggests that symbolic numerical magnitude processing is a good candidate for screening children at risk for developing mathematical difficulties. PMID:26942935

  14. The effects of earthquake measurement concepts and magnitude anchoring on individuals' perceptions of earthquake risk

    USGS Publications Warehouse

    Celsi, R.; Wolfinbarger, M.; Wald, D.

    2005-01-01

    The purpose of this research is to explore earthquake risk perceptions in California. Specifically, we examine the risk beliefs, feelings, and experiences of lay, professional, and expert individuals to explore how risk is perceived and how risk perceptions are formed relative to earthquakes. Our results indicate that individuals tend to perceptually underestimate the degree that earthquake (EQ) events may affect them. This occurs in large part because individuals' personal felt experience of EQ events are generally overestimated relative to experienced magnitudes. An important finding is that individuals engage in a process of "cognitive anchoring" of their felt EQ experience towards the reported earthquake magnitude size. The anchoring effect is moderated by the degree that individuals comprehend EQ magnitude measurement and EQ attenuation. Overall, the results of this research provide us with a deeper understanding of EQ risk perceptions, especially as they relate to individuals' understanding of EQ measurement and attenuation concepts. ?? 2005, Earthquake Engineering Research Institute.

  15. Color-magnitude diagrams for six metal-rich, low-latitude globular clusters

    NASA Technical Reports Server (NTRS)

    Armandroff, Taft E.

    1988-01-01

    Colors and magnitudes for stars on CCD frames for six metal-rich, low-latitude, previously unstudied globular clusters and one well-studied, metal-rich cluster (47 Tuc) have been derived and color-magnitude diagrams have been constructed. The photometry for stars in 47 Tuc are in good agreement with previous studies, while the V magnitudes of the horizontal-branch stars in the six program clusters do not agree with estimates based on secondary methods. The distances to these clusters are different from prior estimates. Redding values are derived for each program cluster. The horizontal branches of the program clusters all appear to lie entirely redwards of the red edge of the instability strip, as is normal for their metallicities.

  16. High-accuracy computation of Delta V magnitude probability densities - Preliminary remarks

    NASA Technical Reports Server (NTRS)

    Chadwick, C.

    1986-01-01

    This paper describes an algorithm for the high accuracy computation of some statistical quantities of the magnitude of a random trajectory correction maneuver (TCM). The trajectory correction velocity increment Delta V is assumed to be a three-component random vector with each component being a normally distributed random scalar having a possibly nonzero mean. Knowledge of the statitiscal properties of the magnitude of a random TCM is important in the planning and execution of maneuver strategies for deep-space missions such as Galileo. The current algorithm involves the numerical integration of a set of differential equations. This approach allows the computation of density functions for specific Delta V magnitude distributions to high accuracy without first having to generate large numbers of random samples. Possible applications of the algorithm to maneuver planning, planetary quarantine evaluation, and guidance success probability calculations are described.

  17. Comparison of water production rates from UV spectroscopy and visual magnitudes for some recent comets

    NASA Technical Reports Server (NTRS)

    Roettger, E. E.; Feldman, P. D.; A'Hearn, M. F.; Festou, M. C.

    1990-01-01

    IUE data on the UV and visible coma emissions of the comets Bradfield, P/Tempel 2, Wilson, and P/Halley, are presently compared with the visual lightcurves from magnitudes reported in the IAU circulars to consider the temporal evolution of these comets. While the water-production rates obtainable from visual magnitudes on the basis of Newburn's (1984) method are consistent with OH-derived rates to first order, they are sometimes either displaced or unable to exhibit the same pre/postperihelion asymmetry. The best agreement is obtained for the relatively dust-free Comet P/Tempel 2. IUE Fine Error Sensor lightcurves are generally in agreement with curves based on total visual magnitude.

  18. STANDARDIZING TYPE Ia SUPERNOVA ABSOLUTE MAGNITUDES USING GAUSSIAN PROCESS DATA REGRESSION

    SciTech Connect

    Kim, A. G.; Aldering, G.; Aragon, C.; Bailey, S.; Childress, M.; Fakhouri, H. K.; Nordin, J.; Thomas, R. C.; Antilogus, P.; Bongard, S.; Canto, A.; Cellier-Holzem, F.; Guy, J.; Baltay, C.; Buton, C.; Kerschhaggl, M.; Kowalski, M.; Chotard, N.; Copin, Y.; Gangler, E.; and others

    2013-04-01

    We present a novel class of models for Type Ia supernova time-evolving spectral energy distributions (SEDs) and absolute magnitudes: they are each modeled as stochastic functions described by Gaussian processes. The values of the SED and absolute magnitudes are defined through well-defined regression prescriptions, so that data directly inform the models. As a proof of concept, we implement a model for synthetic photometry built from the spectrophotometric time series from the Nearby Supernova Factory. Absolute magnitudes at peak B brightness are calibrated to 0.13 mag in the g band and to as low as 0.09 mag in the z = 0.25 blueshifted i band, where the dispersion includes contributions from measurement uncertainties and peculiar velocities. The methodology can be applied to spectrophotometric time series of supernovae that span a range of redshifts to simultaneously standardize supernovae together with fitting cosmological parameters.

  19. Computing approximate random Delta v magnitude probability densities. [for spacecraft trajectory correction

    NASA Technical Reports Server (NTRS)

    Chadwick, C.

    1984-01-01

    This paper describes the development and use of an algorithm to compute approximate statistics of the magnitude of a single random trajectory correction maneuver (TCM) Delta v vector. The TCM Delta v vector is modeled as a three component Cartesian vector each of whose components is a random variable having a normal (Gaussian) distribution with zero mean and possibly unequal standard deviations. The algorithm uses these standard deviations as input to produce approximations to (1) the mean and standard deviation of the magnitude of Delta v, (2) points of the probability density function of the magnitude of Delta v, and (3) points of the cumulative and inverse cumulative distribution functions of Delta v. The approximates are based on Monte Carlo techniques developed in a previous paper by the author and extended here. The algorithm described is expected to be useful in both pre-flight planning and in-flight analysis of maneuver propellant requirements for space missions.

  20. Effort increases sensitivity to reward and loss magnitude in the human brain

    PubMed Central

    Hernandez Lallement, Julen; Kuss, Katarina; Trautner, Peter; Weber, Bernd; Falk, Armin; Fliessbach, Klaus

    2014-01-01

    It is ecologically adaptive that the amount of effort invested to achieve a reward increases the relevance of the resulting outcome. Here, we investigated the effect of effort on activity in reward and loss processing brain areas by using functional magnetic resonance imaging. In total, 28 subjects were endowed with monetary rewards of randomly varying magnitude after performing arithmetic calculations that were either difficult (high effort), easy (low effort) or already solved (no effort). Subsequently, a forced donation took place, where a varying part of the endowment was transferred to a charity organization, causing a loss for the subject. Results show that reward magnitude positively modulates activity in reward-processing brain areas (subgenual anterior cingulate cortex and nucleus accumbens) only in the high effort condition. Furthermore, anterior insular activity was positively modulated by loss magnitude only after high effort. The results strongly suggest an increasing relevance of outcomes with increasing previous effort. PMID:23202663

  1. Outcome Probability versus Magnitude: When Waiting Benefits One at the Cost of the Other

    PubMed Central

    Young, Michael E.; Webb, Tara L.; Rung, Jillian M.; McCoy, Anthony W.

    2014-01-01

    Using a continuous impulsivity and risk platform (CIRP) that was constructed using a video game engine, choice was assessed under conditions in which waiting produced a continuously increasing probability of an outcome with a continuously decreasing magnitude (Experiment 1) or a continuously increasing magnitude of an outcome with a continuously decreasing probability (Experiment 2). Performance in both experiments reflected a greater desire for a higher probability even though the corresponding wait times produced substantive decreases in overall performance. These tendencies are considered to principally reflect hyperbolic discounting of probability, power discounting of magnitude, and the mathematical consequences of different response rates. Behavior in the CIRP is compared and contrasted with that in the Balloon Analogue Risk Task (BART). PMID:24892657

  2. Outcome probability versus magnitude: when waiting benefits one at the cost of the other.

    PubMed

    Young, Michael E; Webb, Tara L; Rung, Jillian M; McCoy, Anthony W

    2014-01-01

    Using a continuous impulsivity and risk platform (CIRP) that was constructed using a video game engine, choice was assessed under conditions in which waiting produced a continuously increasing probability of an outcome with a continuously decreasing magnitude (Experiment 1) or a continuously increasing magnitude of an outcome with a continuously decreasing probability (Experiment 2). Performance in both experiments reflected a greater desire for a higher probability even though the corresponding wait times produced substantive decreases in overall performance. These tendencies are considered to principally reflect hyperbolic discounting of probability, power discounting of magnitude, and the mathematical consequences of different response rates. Behavior in the CIRP is compared and contrasted with that in the Balloon Analogue Risk Task (BART). PMID:24892657

  3. Chile2015: Lévy Flight and Long-Range Correlation Analysis of Earthquake Magnitudes in Chile

    NASA Astrophysics Data System (ADS)

    Beccar-Varela, Maria P.; Gonzalez-Huizar, Hector; Mariani, Maria C.; Serpa, Laura F.; Tweneboah, Osei K.

    2016-07-01

    The stochastic Truncated Lévy Flight model and detrended fluctuation analysis (DFA) are used to investigate the temporal distribution of earthquake magnitudes in Chile. We show that Lévy Flight is appropriated for modeling the time series of the magnitudes of the earthquakes. Furthermore, DFA shows that these events present memory effects, suggesting that the magnitude of impeding earthquakes depends on the magnitude of previous earthquakes. Based on this dependency, we use a non-linear regression to estimate the magnitude of the 2015, M8.3 Illapel earthquake based on the magnitudes of the previous events.

  4. Effect of Spinal Manipulation Thrust Magnitude on Trunk Mechanical Thresholds of Lateral Thalamic Neurons

    PubMed Central

    Reed, William R.; Pickar, Joel G.; Sozio, Randall S.; Long, Cynthia R.

    2014-01-01

    Objectives High velocity low amplitude spinal manipulation (HVLA-SM), as performed by manual therapists (eg, doctors of chiropractic and osteopathy) results in mechanical hypoalgesia in clinical settings. This hypoalgesic effect has previously been attributed to alterations in peripheral and/or central pain processing. The objective of this study was to determine whether thrust magnitude of a simulated HVLA-SM alters mechanical trunk response thresholds in wide dynamic range (WDR) and/or nociceptive specific (NS) lateral thalamic neurons. Methods Extracellular recordings were carried out in the thalamus of 15 anesthetized Wistar rats. Lateral thalamic neurons having receptive fields which included the lumbar dorsal-lateral trunk were characterized as either WDR (n=22) or NS (n=25). Response thresholds to electronic von Frey (rigid tip) mechanical trunk stimuli were determined in three directions (dorsal-ventral, 45°caudalward, and 45°cranialward) prior to and immediately following the dorsal-ventral delivery of a 100ms HVLA-SM at three thrust magnitudes (control, 55%, 85% body weight; (BW)). Results There was a significant difference in mechanical threshold between 85% BW manipulation and control thrust magnitudes in the dorsal-ventral direction in NS neurons (p=.01). No changes were found in WDR neurons at either HVLA-SM thrust magnitude. Conclusions This study is the first to investigate the effect of HVLA-SM thrust magnitude on WDR and NS lateral thalamic mechanical response threshold. Our data suggest that at the single lateral thalamic neuron level, there may be a minimal spinal manipulative thrust magnitude required to elicit an increase in trunk mechanical response thresholds. PMID:24928636

  5. Robust automatic photometry of local galaxies from SDSS. Dissecting the color magnitude relation with color profiles

    NASA Astrophysics Data System (ADS)

    Consolandi, Guido; Gavazzi, Giuseppe; Fumagalli, Michele; Dotti, Massimo; Fossati, Matteo

    2016-06-01

    We present an automatic procedure to perform reliable photometry of galaxies on SDSS images. We selected a sample of 5853 galaxies in the Coma and Virgo superclusters. For each galaxy, we derive Petrosian g and i magnitudes, surface brightness and color profiles. Unlike the SDSS pipeline, our procedure is not affected by the well known shredding problem and efficiently extracts Petrosian magnitudes for all galaxies. Hence we derived magnitudes even from the population of galaxies missed by the SDSS which represents ~25% of all local supercluster galaxies and ~95% of galaxies with g < 11 mag. After correcting the g and i magnitudes for Galactic and internal extinction, the blue and red sequences in the color magnitude diagram are well separated, with similar slopes. In addition, we study (i) the color-magnitude diagrams in different galaxy regions, the inner (r ≤ 1 kpc), intermediate (0.2RPet ≤ r ≤ 0.3RPet) and outer, disk-dominated (r ≥ 0.35RPet)) zone; and (ii), we compute template color profiles, discussing the dependences of the templates on the galaxy masses and on their morphological type. The two analyses consistently lead to a picture where elliptical galaxies show no color gradients, irrespective of their masses. Spirals, instead, display a steeper gradient in their color profiles with increasing mass, which is consistent with the growing relevance of a bulge and/or a bar component above 1010 M⊙. Full Table A.1 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/591/A38

  6. Magnitude-dependent epidemic-type aftershock sequences model for earthquakes

    NASA Astrophysics Data System (ADS)

    Spassiani, Ilaria; Sebastiani, Giovanni

    2016-04-01

    We propose a version of the pure temporal epidemic type aftershock sequences (ETAS) model: the ETAS model with correlated magnitudes. As for the standard case, we assume the Gutenberg-Richter law to be the probability density for the magnitudes of the background events. Instead, the magnitude of the triggered shocks is assumed to be probabilistically dependent on that of the relative mother events. This probabilistic dependence is motivated by some recent works in the literature and by the results of a statistical analysis made on some seismic catalogs [Spassiani and Sebastiani, J. Geophys. Res. 121, 903 (2016), 10.1002/2015JB012398]. On the basis of the experimental evidences obtained in the latter paper for the real catalogs, we theoretically derive the probability density function for the magnitudes of the triggered shocks proposed in Spassiani and Sebastiani and there used for the analysis of two simulated catalogs. To this aim, we impose a fundamental condition: averaging over all the magnitudes of the mother events, we must obtain again the Gutenberg-Richter law. This ensures the validity of this law at any event's generation when ignoring past seismicity. The ETAS model with correlated magnitudes is then theoretically analyzed here. In particular, we use the tool of the probability generating function and the Palm theory, in order to derive an approximation of the probability of zero events in a small time interval and to interpret the results in terms of the interevent time between consecutive shocks, the latter being a very useful random variable in the assessment of seismic hazard.

  7. Development of magnitude scaling relationship for earthquake early warning system in South Korea

    NASA Astrophysics Data System (ADS)

    Sheen, D.

    2011-12-01

    Seismicity in South Korea is low and magnitudes of recent earthquakes are mostly less than 4.0. However, historical earthquakes of South Korea reveal that many damaging earthquakes had occurred in the Korean Peninsula. To mitigate potential seismic hazard in the Korean Peninsula, earthquake early warning (EEW) system is being installed and will be operated in South Korea in the near future. In order to deliver early warnings successfully, it is very important to develop stable magnitude scaling relationships. In this study, two empirical magnitude relationships are developed from 350 events ranging in magnitude from 2.0 to 5.0 recorded by the KMA and the KIGAM. 1606 vertical component seismograms whose epicentral distances are within 100 km are chosen. The peak amplitude and the maximum predominant period of the initial P wave are used for finding magnitude relationships. The peak displacement of seismogram recorded at a broadband seismometer shows less scatter than the peak velocity of that. The scatters of the peak displacement and the peak velocity of accelerogram are similar to each other. The peak displacement of seismogram differs from that of accelerogram, which means that two different magnitude relationships for each type of data should be developed. The maximum predominant period of the initial P wave is estimated after using two low-pass filters, 3 Hz and 10 Hz, and 10 Hz low-pass filter yields better estimate than 3 Hz. It is found that most of the peak amplitude and the maximum predominant period are estimated within 1 sec after triggering.

  8. Analysis of changes in the magnitude, frequency, and seasonality of heavy precipitation over the contiguous USA

    NASA Astrophysics Data System (ADS)

    Mallakpour, Iman; Villarini, Gabriele

    2016-08-01

    Auc(bstract) Gridded daily precipitation observations over the contiguous USA are used to investigate the past observed changes in the frequency and magnitude of heavy precipitation, and to examine its seasonality. Analyses are based on the Climate Prediction Center (CPC) daily precipitation data from 1948 to 2012. We use a block maxima approach to identify changes in the magnitude of heavy precipitation and a peak-over-threshold (POT) approach for the changes in the frequency. The results of this study show that there is a stronger signal of change in the frequency rather than in the magnitude of heavy precipitation events. Also, results show an increasing trend in the frequency of heavy precipitation over large areas of the contiguous USA with the most notable exception of the US Northwest. These results indicate that over the last 65 years, the stronger storms are not getting stronger, but a larger number of heavy precipitation events have been observed. The annual maximum precipitation and annual frequency of heavy precipitation reveal a marked seasonality over the contiguous USA. However, we could not find any evidence suggesting shifting in the seasonality of annual maximum precipitation by investigating whether the day of the year at which the maximum precipitation occurs has changed over time. Furthermore, we examine whether the year-to-year variations in the frequency and magnitude of heavy precipitation can be explained in terms of climate variability driven by the influence of the Atlantic and Pacific Oceans. Our findings indicate that the climate variability of both the Atlantic and Pacific Oceans can exert a large control on the precipitation frequency and magnitude over the contiguous USA. Also, the results indicate that part of the spatial and temporal features of the relationship between climate variability and heavy precipitation magnitude and frequency can be described by one or more of the climate indices considered here.

  9. Automatic detection and rapid determination of earthquake magnitude by wavelet multiscale analysis of the primary arrival

    NASA Astrophysics Data System (ADS)

    Dando, B.; Simons, F. J.; Allen, R. M.

    2006-12-01

    Earthquake early warning systems save lives. It is of great importance that networked systems of seismometers be equipped with reliable tools to make rapid determinations of earthquake magnitude in the few to tens of seconds before the damaging ground motion occurs. A new fully automated algorithm based on the discrete wavelet transform detects as well as analyzes the incoming first arrival with unmatched accuracy and precision, estimating the final magnitude to within a single unit from the first few seconds of the P wave. The curious observation that such brief segments of the seismogram may contain information about the final magnitude even of very large earthquakes, which occur on faults that may rupture over tens of seconds, is central to a debate in the seismological community which we hope to stimulate but cannot attempt to address within the scope of this paper. Wavelet coefficients of the seismogram can be determined extremely rapidly and efficiently by the fast lifting wavelet transform. Extracting amplitudes at individual scales is a very simple procedure, involving a mere handful of lines of computer code. Scale-dependent thresholded amplitudes derived from the wavelet transform of the first 3--4 seconds of an incoming seismic P arrival are predictive of earthquake magnitude, with errors of one magnitude unit for seismograms recorded up to 150 km away from the earthquake source. Our procedure is a simple yet extremely efficient tool for implementation on low-power recording stations. It provides an accurate and precise method of autonomously detecting the incoming P wave and predicting the magnitude of the source from the scale-dependent character of its amplitude well before the arrival of damaging ground motion. Provided a dense array of networked seismometers exists, our procedure should become the tool of choice for earthquake early warning systems worldwide.

  10. Cosmological parameter extraction and biases from type Ia supernova magnitude evolution

    NASA Astrophysics Data System (ADS)

    Linden, S.; Virey, J.-M.; Tilquin, A.

    2009-11-01

    We study different one-parametric models of type Ia supernova magnitude evolution on cosmic time scales. Constraints on cosmological and supernova evolution parameters are obtained by combined fits on the actual data coming from supernovae, the cosmic microwave background, and baryonic acoustic oscillations. We find that the best-fit values imply supernova magnitude evolution such that high-redshift supernovae appear some percent brighter than would be expected in a standard cosmos with a dark energy component. However, the errors on the evolution parameters are of the same order, and data are consistent with nonevolving magnitudes at the 1σ level, except for special cases. We simulate a future data scenario where SN magnitude evolution is allowed for, and neglect the possibility of such an evolution in the fit. We find the fiducial models for which the wrong model assumption of nonevolving SN magnitude is not detectable, and for which biases on the fitted cosmological parameters are introduced at the same time. Of the cosmological parameters, the overall mass density ΩM has the strongest chances to be biased due to the wrong model assumption. Whereas early-epoch models with a magnitude offset Δ m˜ z2 show up to be not too dangerous when neglected in the fitting procedure, late epoch models with Δ m˜√{z} have high chances of undetectably biasing the fit results. Centre de Physique Théorique is UMR 6207 - “Unité Mixte de Recherche” of CNRS and of the Universities “de Provence”, “de la Mediterranée”, and “du Sud Toulon-Var” - Laboratory affiliated with FRUMAM (FR2291).

  11. Magnitude-dependent epidemic-type aftershock sequences model for earthquakes.

    PubMed

    Spassiani, Ilaria; Sebastiani, Giovanni

    2016-04-01

    We propose a version of the pure temporal epidemic type aftershock sequences (ETAS) model: the ETAS model with correlated magnitudes. As for the standard case, we assume the Gutenberg-Richter law to be the probability density for the magnitudes of the background events. Instead, the magnitude of the triggered shocks is assumed to be probabilistically dependent on that of the relative mother events. This probabilistic dependence is motivated by some recent works in the literature and by the results of a statistical analysis made on some seismic catalogs [Spassiani and Sebastiani, J. Geophys. Res. 121, 903 (2016)10.1002/2015JB012398]. On the basis of the experimental evidences obtained in the latter paper for the real catalogs, we theoretically derive the probability density function for the magnitudes of the triggered shocks proposed in Spassiani and Sebastiani and there used for the analysis of two simulated catalogs. To this aim, we impose a fundamental condition: averaging over all the magnitudes of the mother events, we must obtain again the Gutenberg-Richter law. This ensures the validity of this law at any event's generation when ignoring past seismicity. The ETAS model with correlated magnitudes is then theoretically analyzed here. In particular, we use the tool of the probability generating function and the Palm theory, in order to derive an approximation of the probability of zero events in a small time interval and to interpret the results in terms of the interevent time between consecutive shocks, the latter being a very useful random variable in the assessment of seismic hazard.

  12. Variability in magnitude of paleoearthquakes revealed by trenching and historical records, along the Haiyuan Fault, China

    NASA Astrophysics Data System (ADS)

    Liu-Zeng, Jing; Shao, Yanxiu; Klinger, Yann; Xie, Kejia; Yuan, Daoyuang; Lei, Zhongsheng

    2015-12-01

    Paleoseismology provides fundamental data for generalizing earthquake recurrence behavior, by revealing past surface-rupturing events. Determining the size of paleoseismic events is notoriously more challenging than their timing. Paleoearthquakes exposed in trenches are vaguely defined as large enough to break to the surface and often assumed to be similar in size. Here we show an example where the paleoseismic record includes events of both moderate and large magnitudes. At the Salt Lake site on the active left-lateral Haiyuan Fault, northern Tibetan Plateau, a high-resolution stratigraphic sequence recorded three and possibly four events since A.D. 1500, constrained by accelerator mass spectrometry 14C dating. Historical accounts of earthquake damage in the study region suggest that several earthquakes exposed in the trenches markedly differ in magnitude. With the exception of the most recent M~8 earthquake that occurred in A.D. 1920, two earlier events, which occurred in A.D. 1760 (or 1709) and 1638, respectively, are considerably smaller, with magnitude M < 7 and more likely M~6 or less. Thus, this section of the Haiyuan Fault that broke during moderate-magnitude events failed again after a short interval during a large Mw 7.8-8.3 earthquake, as part of a larger multisegment rupture. Our study shows that moderate-magnitude events can be preserved in the stratigraphy and exposed by paleoseismic trenching under ideal conditions, for instance, if sedimentation is fast enough and there is no hiatus in deposition. Eventually, the data presented add to the growing body of paleoseismic records containing events of different magnitudes with a large variability in rupture length and coseismic slip.

  13. Magnitudes and moment-duration scaling of low-frequency earthquakes beneath southern Vancouver Island

    NASA Astrophysics Data System (ADS)

    Bostock, M. G.; Thomas, A. M.; Savard, G.; Chuang, L.; Rubin, A. M.

    2015-09-01

    We employ 130 low-frequency earthquake (LFE) templates representing tremor sources on the plate boundary below southern Vancouver Island to examine LFE magnitudes. Each template is assembled from hundreds to thousands of individual LFEs, representing over 269,000 independent detections from major episodic-tremor-and-slip (ETS) events between 2003 and 2013. Template displacement waveforms for direct P and S waves at near epicentral distances are remarkably simple at many stations, approaching the zero-phase, single pulse expected for a point dislocation source in a homogeneous medium. High spatiotemporal precision of template match-filtered detections facilitates precise alignment of individual LFE detections and analysis of waveforms. Upon correction for 1-D geometrical spreading, attenuation, free surface magnification and radiation pattern, we solve a large, sparse linear system for 3-D path corrections and LFE magnitudes for all detections corresponding to a single-ETS template. The spatiotemporal distribution of magnitudes indicates that typically half the total moment release occurs within the first 12-24 h of LFE activity during an ETS episode when tidal sensitivity is low. The remainder is released in bursts over several days, particularly as spatially extensive rapid tremor reversals (RTRs), during which tidal sensitivity is high. RTRs are characterized by large-magnitude LFEs and are most strongly expressed in the updip portions of the ETS transition zone and less organized at downdip levels. LFE magnitude-frequency relations are better described by power law than exponential distributions although they exhibit very high b values ≥˜5. We examine LFE moment-duration scaling by generating templates using detections for limiting magnitude ranges (MW<1.5, MW≥2.0). LFE duration displays a weaker dependence upon moment than expected for self-similarity, suggesting that LFE asperities are limited in fault dimension and that moment variation is dominated by

  14. Magnitude-dependent epidemic-type aftershock sequences model for earthquakes.

    PubMed

    Spassiani, Ilaria; Sebastiani, Giovanni

    2016-04-01

    We propose a version of the pure temporal epidemic type aftershock sequences (ETAS) model: the ETAS model with correlated magnitudes. As for the standard case, we assume the Gutenberg-Richter law to be the probability density for the magnitudes of the background events. Instead, the magnitude of the triggered shocks is assumed to be probabilistically dependent on that of the relative mother events. This probabilistic dependence is motivated by some recent works in the literature and by the results of a statistical analysis made on some seismic catalogs [Spassiani and Sebastiani, J. Geophys. Res. 121, 903 (2016)10.1002/2015JB012398]. On the basis of the experimental evidences obtained in the latter paper for the real catalogs, we theoretically derive the probability density function for the magnitudes of the triggered shocks proposed in Spassiani and Sebastiani and there used for the analysis of two simulated catalogs. To this aim, we impose a fundamental condition: averaging over all the magnitudes of the mother events, we must obtain again the Gutenberg-Richter law. This ensures the validity of this law at any event's generation when ignoring past seismicity. The ETAS model with correlated magnitudes is then theoretically analyzed here. In particular, we use the tool of the probability generating function and the Palm theory, in order to derive an approximation of the probability of zero events in a small time interval and to interpret the results in terms of the interevent time between consecutive shocks, the latter being a very useful random variable in the assessment of seismic hazard. PMID:27176281

  15. On the absolute magnitude of RR Lyrae stars - UU Ceti, RV Phoenicis, and W Tucanae

    NASA Astrophysics Data System (ADS)

    Cacciari, C.; Clementini, G.; Fernley, J. A.

    1992-09-01

    IR JHK light curves are presented for the RRab Lyrae stars UU Ceti, RV Phoenicis, and W Tucanae. These stars have similar periods and metallicities data, together with BVRI photometry and CORAVEL radial velocity data and Walraven photometry are used to derive absolute magnitudes for the stars using two formulations of the Baade-Wesselink method: (1) the infrared flux version and (2) the surface brightness version. The two methods are directly compared and their respective advantages and shortcomings are discussed. Finally, a comparison is made with previous results on the absolute magnitude of RR Lyrae variables.

  16. Influence of weak motion data to magnitude dependence of PGA prediction model in Austria

    NASA Astrophysics Data System (ADS)

    Jia, Yan

    2015-04-01

    Data recorded by the STS2-sensors at the Austrian Seismic Network were differentiated and used to derive the PGA prediction model for Austria (Jia and Lenhardt, 2010). Before using it to our hazard assessment and real time shakemap, it is necessary to validate this model and obtain a deep understanding about it. In this paper, influence of weak motion data to the magnitude dependence of our prediction model was studied. In addition, spatial PGA residuals between the measurements and predictions were investigated as well. There are 127 earthquakes with a magnitude between 3 and 5.4 that were used to derive the PGA prediction model published in 2011. Unfortunately, 90% of used PGA measurements were made for the events with a magnitude smaller than 4. Only ten quakes among them have a magnitude larger than 4, which is the important magnitude range that needs our attention and hazard assessment. In this investigation, 127 earthquakes were divided into two groups: the first group only includes events with a magnitude smaller than 4, while the second group contains quakes with a magnitude larger than 4. By using the same modeling for estimating PGA attenuation in 2011, coefficients of the model were inverted from the measurements in two groups and compared to the one based on the complete data set. It was found that the group with the weak quakes returned results that only have small differences to the one from all 127 events, while the group with strong quakes (ml> 4) gave greater magnitude dependence than the model published in 2011. The distance coefficients stayed nearly unchanged for all three inversions. As the second step, spatial PGA residuals between the measurements and the predictions from our model were investigated. As explained in Jia and Lenhardt (2013), there are some differences in the site amplifications between the West- and the East-Austria. For a fair comparison, residuals were normalized for each station before the investigation. Then normalized

  17. Automatic detection and rapid determination of earthquake magnitude by wavelet multiscale analysis of the primary arrival

    NASA Astrophysics Data System (ADS)

    Simons, Frederik J.; Dando, Ben D. E.; Allen, Richard M.

    2006-10-01

    Earthquake early warning systems must save lives. It is of great importance that networked systems of seismometers be equipped with reliable tools to make rapid determinations of earthquake magnitude in the few to tens of seconds before the damaging ground motion occurs. A new fully automated algorithm based on the discrete wavelet transform detects as well as analyzes the incoming first arrival with great accuracy and precision, estimating the final magnitude to within a single unit from the first few seconds of the P wave.

  18. Dynamics of subjective discomfort in motion sickness as measured with a magnitude estimation method

    NASA Technical Reports Server (NTRS)

    Bock, O. L.; Oman, C. M.

    1982-01-01

    Eight subjects, wearing left-right vision reversing goggles, executed sequences of controlled active head movements to provoke motion sickness. Head movement sequences were interspaced with periods of eye closure and no head movement to permit partial remission of symptoms between sequences. Subjects reported the level of discomfort experienced by using a magnitude estimation technique derived from Stevens' (1957) ratio scaling method. Using this approach, we demonstrated that the time course of subjective discomfort exhibits a profile, similar in all our subjects, characterized by both fast and slow response components. The potential usefulness of magnitude estimation for research on the dynamic properties of the mechanism generating motion sickness symptoms is discussed.

  19. Spectral P-wave magnitudes, magnitude spectra and other source parameters for the 1990 southern Sudan and the 2005 Lake Tanganyika earthquakes

    NASA Astrophysics Data System (ADS)

    Moussa, Hesham Hussein Mohamed

    2008-10-01

    Teleseismic Broadband seismograms of P-waves from the May 1990 southern Sudan and the December, 2005 Lake Tanganyika earthquakes; the western branch of the East African Rift System at different azimuths have been investigated on the basis of magnitude spectra. The two earthquakes are the largest shocks in the East African Rift System and its extension in southern Sudan. Focal mechanism solutions along with geological evidences suggest that the first event represents a complex style of the deformation at the intersection of the northern branch of the western branch of the East African Rift and Aswa Shear Zone while the second one represents the current tensional stress on the East African Rift. The maximum average spectral magnitude for the first event is determined to be 6.79 at 4 s period compared to 6.33 at 4 s period for the second event. The other source parameters for the two earthquakes were also estimated. The first event had a seismic moment over fourth that of the second one. The two events are radiated from patches of faults having radii of 13.05 and 7.85 km, respectively. The average displacement and stress drop are estimated to be 0.56 m and 1.65 MPa for the first event and 0.43 m and 2.20 MPa for the second one. The source parameters that describe inhomogeneity of the fault are also determined from the magnitude spectra. These additional parameters are complexity, asperity radius, displacements across the asperity and ambient stress drop. Both events produce moderate rupture complexity. Compared to the second event, the first event is characterized by relatively higher complexity, a low average stress drop and a high ambient stress. A reasonable explanation for the variations in these parameters may suggest variation in the strength of the seismogenic fault which provides the relations between the different source parameters. The values of stress drops and the ambient stresses estimated for both events indicate that these earthquakes are of interplate

  20. Strain magnitude-dependent calcific marker expression in valvular and vascular cells.

    PubMed

    Ferdous, Zannatul; Jo, Hanjoong; Nerem, Robert M

    2013-01-01

    Aortic valve disease and atherosclerosis tend to coexist in most patients with cardiovascular disease; however, the causes and mechanisms of disease development in heart valves are still not clearly understood. To understand the contributions of the magnitude of cyclic strain (5% hypotension, 10% physiological, and 15% hypertension) in calcification, we used a model system of tissue-engineered collagen gels containing human aortic smooth muscle cells and human aortic valvular interstitial cells, both isolated from noncalcific heart transplant tissue. The compacted collagen gels were cultured in osteogenic media for 3 weeks in a custom-designed bioreactor and all assessments were performed at the end of the culture period. The major finding of this study is that bone morphogenic protein (BMP)-2 and BMP-4 and transforming growth factor-β1 mRNA expression significantly changed in response to the magnitude of applied strain in valvular cells, while the lowest expression was observed for the representative physiological strain. On the other hand, mRNA expression in vascular cells did not vary in response to the magnitude of strain. Regarding BMP-2 and BMP-4 protein expression determined by immunostaining, trends were similar to mRNA expression in vascular and valvular cells, where only valvular cells showed a varied protein expression depending on the magnitude of the strain applied. Our results suggest that cellular differences exist between vascular and valvular cells in their response to altered levels of cyclic strain during calcification. PMID:23548742

  1. Children's Representation of Symbolic and Nonsymbolic Magnitude Examined with the Priming Paradigm

    ERIC Educational Resources Information Center

    Defever, Emmy; Sasanguie, Delphine; Gebuis, Titia; Reynvoet, Bert

    2011-01-01

    How people process and represent magnitude has often been studied using number comparison tasks. From the results of these tasks, a comparison distance effect (CDE) is generated, showing that it is easier to discriminate two numbers that are numerically further apart (e.g., 2 and 8) compared with numerically closer numbers (e.g., 6 and 8).…

  2. What magnitude are observed non-target impacts from weed biocontrol?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A systematic review focused by plant on non-target impacts from agents deliberately introduced for the biological control of weeds found significant non-target impacts to be rare. The magnitude of direct impact of 43 biocontrol agents on 140 non-target plants was retrospectively categorized using a ...

  3. An Association between Understanding Cardinality and Analog Magnitude Representations in Preschoolers

    ERIC Educational Resources Information Center

    Wagner, Jennifer B.; Johnson, Susan C.

    2011-01-01

    The preschool years are a time of great advances in children's numerical thinking, most notably as they master verbal counting. The present research assessed the relation between analog magnitude representations and cardinal number knowledge in preschool-aged children to ask two questions: (1) Is there a relationship between acuity in the analog…

  4. Mind the gap: tightening the mass-richness relation with magnitude gaps

    NASA Astrophysics Data System (ADS)

    Hearin, Andrew P.; Zentner, Andrew R.; Newman, Jeffrey A.; Berlind, Andreas A.

    2013-04-01

    We investigate the potential to improve optical tracers of cluster mass by exploiting measurements of the magnitude gap, m12, defined as the difference between the r-band absolute magnitudes of the two brightest cluster members. We find that in a mock sample of galaxy groups and clusters constructed from the Bolshoi simulation, the scatter about the mass-richness relation decreases by ˜15-20 per cent when magnitude gap information is included. A similar trend is evident in a volume-limited, spectroscopic sample of galaxy groups observed in the Sloan Digital Sky Survey (SDSS). We find that SDSS groups with small magnitude gaps are richer than large-gap groups at fixed values of the one-dimensional velocity dispersion among group members σv, which we use as a mass proxy. We demonstrate explicitly that m12 contains information about cluster mass that supplements the information provided by group richness and the luminosity of the brightest cluster galaxy, LBCG. In so doing, we show that the luminosities of the members of a group with richness N are inconsistent with the distribution of luminosities that results from N random draws from the global galaxy luminosity function. As the cosmological constraining power of galaxy clusters is limited by the precision in cluster mass determination, our findings suggest a new way to improve the cosmological constraints derived from galaxy clusters.

  5. Direct Magnitude Estimation of Articulation Rate in Boys with Fragile X Syndrome

    ERIC Educational Resources Information Center

    Zajac, David J.; Harris, Adrianne A.; Roberts, Joanne E.; Martin, Gary E.

    2009-01-01

    Purpose: To compare the perceived articulation rate of boys with fragile X syndrome (FXS) with that of chronologically age-matched (CA) boys and to determine segmental and/or prosodic factors that account for perceived rate. Method: Ten listeners used direct magnitude estimation procedures to judge the articulation rates of 7 boys with FXS only, 5…

  6. How Sequential Changes in Reward Magnitude Modulate Cognitive Flexibility: Evidence from Voluntary Task Switching

    ERIC Educational Resources Information Center

    Fröber, Kerstin; Dreisbach, Gesine

    2016-01-01

    There is much evidence that the prospect of reward modulates cognitive control in terms of more stable behavior. Increases in expected reward magnitude, however, have been suggested to increase flexible behavior as evidenced by reduced switch costs. In a series of experiments, the authors provide evidence that this increased cognitive flexibility…

  7. Developmental Specialization in the Right Intraparietal Sulcus for the Abstract Representation of Numerical Magnitude

    ERIC Educational Resources Information Center

    Holloway, Ian D.; Ansari, Daniel

    2010-01-01

    Because number is an abstract quality of a set, the way in which a number is externally represented does not change its quantitative meaning. In this study, we examined the development of the brain regions that support format-independent representation of numerical magnitude. We asked children and adults to perform both symbolic (Hindu-Arabic…

  8. Mental representations of magnitude and order: a dissociation by sensorimotor learning.

    PubMed

    Badets, Arnaud; Boutin, Arnaud; Heuer, Herbert

    2015-05-01

    Numbers and spatially directed actions share cognitive representations. This assertion is derived from studies that have demonstrated that the processing of small- and large-magnitude numbers facilitates motor behaviors that are directed to the left and right, respectively. However, little is known about the role of sensorimotor learning for such number-action associations. In this study, we show that sensorimotor learning in a serial reaction-time task can modify the associations between number magnitudes and spatially directed movements. Experiments 1 and 3 revealed that this effect is present only for the learned sequence and does not transfer to a novel unpracticed sequence. Experiments 2 and 4 showed that the modification of stimulus-action associations by sensorimotor learning does not occur for other sets of ordered stimuli such as letters of the alphabet. These results strongly suggest that numbers and actions share a common magnitude representation that differs from the common order representation shared by letters and spatially directed actions. Only the magnitude representation, but not the order representation, can be modified episodically by sensorimotor learning.

  9. The Magnitude 6.7 Northridge, California, Earthquake of January 17, 1994

    NASA Technical Reports Server (NTRS)

    Donnellan, A.

    1994-01-01

    The most damaging earthquake in the United States since 1906 struck northern Los Angeles on January 17.1994. The magnitude 6.7 Northridge earthquake produced a maximum of more than 3 meters of reverse (up-dip) slip on a south-dipping thrust fault rooted under the San Fernando Valley and projecting north under the Santa Susana Mountains.

  10. Estimators of The Magnitude-Squared Spectrum and Methods for Incorporating SNR Uncertainty.

    PubMed

    Lu, Yang; Loizou, Philipos C

    2011-07-01

    Statistical estimators of the magnitude-squared spectrum are derived based on the assumption that the magnitude-squared spectrum of the noisy speech signal can be computed as the sum of the (clean) signal and noise magnitude-squared spectra. Maximum a posterior (MAP) and minimum mean square error (MMSE) estimators are derived based on a Gaussian statistical model. The gain function of the MAP estimator was found to be identical to the gain function used in the ideal binary mask (IdBM) that is widely used in computational auditory scene analysis (CASA). As such, it was binary and assumed the value of 1 if the local SNR exceeded 0 dB, and assumed the value of 0 otherwise. By modeling the local instantaneous SNR as an F-distributed random variable, soft masking methods were derived incorporating SNR uncertainty. The soft masking method, in particular, which weighted the noisy magnitude-squared spectrum by the a priori probability that the local SNR exceeds 0 dB was shown to be identical to the Wiener gain function. Results indicated that the proposed estimators yielded significantly better speech quality than the conventional MMSE spectral power estimators, in terms of yielding lower residual noise and lower speech distortion. PMID:21886543

  11. Effect of Reinforcer Magnitude on Performance Maintained by Progressive-Ratio Schedules

    ERIC Educational Resources Information Center

    Rickard, J. F.; Body, S.; Zhang, Z.; Bradshaw, C. M.; Szabadi, E.

    2009-01-01

    This experiment examined the relationship between reinforcer magnitude and quantitative measures of performance on progressive-ratio schedules. Fifteen rats were trained under a progressive-ratio schedule in seven phases of the experiment in which the volume of a 0.6-M sucrose solution reinforcer was varied within the range 6-300 microliters.…

  12. Functional Communication Training without Extinction Using Concurrent Schedules of Differing Magnitudes of Reinforcement in Classrooms

    ERIC Educational Resources Information Center

    Davis, Dawn H.; Fredrick, Laura D.; Alberto, Paul A.; Gama, Roberto

    2012-01-01

    This study investigated the effects of functional communication training (FCT) implemented with concurrent schedules of differing magnitudes of reinforcement in lieu of extinction to reduce inappropriate behaviors and increase alternative mands. Participants were four adolescent students diagnosed with severe emotional and behavior disorders…

  13. Does the Measurement or Magnitude of Academic Entitlement Change over Time?

    ERIC Educational Resources Information Center

    Sessoms, John; Finney, Sara J.; Kopp, Jason P.

    2016-01-01

    Academic entitlement (AE) characterizes students who believe they deserve positive academic outcomes independent of performance. Using the Academic Entitlement Questionnaire, we evaluated the longitudinal stability of the measurement and magnitude of AE. Results indicated partial measurement invariance, slight average increase in AE, and…

  14. On magnitudes in memory: An internal clock account of space-time interaction.

    PubMed

    Cai, Zhenguang G; Connell, Louise

    2016-07-01

    Traditionally, research on time perception has diverged into a representational approach that focuses on the interaction between time and non-temporal magnitude information like spatial distance, and a mechanistic approach that emphasizes the workings and timecourse of components within an internal clock. We combined these approaches in order to identify the locus of space-time interaction effects in the mechanistic framework of the internal clock model. In three experiments, we contrasted the effects of spatial distance (a long- vs. short-distance line) on time perception with those of visual flicker (a flickering vs. static stimulus) in a duration reproduction paradigm. We found that both a flickering stimulus and a long-distance line lengthened reproduced time when presented during time encoding. However, when presented during time reproduction, a flickering stimulus shortened reproduced time but a long-distance line had no effect. The results thus show that, while visual flickers affects duration accumulation itself, spatial distance instead biases the memory of the accumulated duration. These findings are consistent with a clock-magnitude account of space-time interaction whereby both temporal duration and spatial distance are represented as mental magnitudes that can interfere with each other while being kept in memory, and places the locus of interaction between temporal and non-temporal magnitude dimensions at the memory maintenance stage of the internal clock model.

  15. Of magnitudes and metaphors: explaining cognitive interactions between space, time, and number.

    PubMed

    Winter, Bodo; Marghetis, Tyler; Matlock, Teenie

    2015-03-01

    Space, time, and number are fundamental to how we act within and reason about the world. These three experiential domains are systematically intertwined in behavior, language, and the brain. Two main theories have attempted to account for cross-domain interactions. A Theory of Magnitude (ATOM) posits a domain-general magnitude system. Conceptual Metaphor Theory (CMT) maintains that cross-domain interactions are manifestations of asymmetric mappings that use representations of space to structure the domains of number and time. These theories are often viewed as competing accounts. We propose instead that ATOM and CMT are complementary, each illuminating different aspects of cross-domain interactions. We argue that simple representations of magnitude cannot, on their own, account for the rich, complex interactions between space, time and number described by CMT. On the other hand, ATOM is better at accounting for low-level and language-independent associations that arise early in ontogeny. We conclude by discussing how magnitudes and metaphors are both needed to understand our neural and cognitive web of space, time and number.

  16. The Magnitude, Destinations, and Determinants of Mathematics and Science Teacher Turnover

    ERIC Educational Resources Information Center

    Ingersoll, Richard M.; May, Henry

    2012-01-01

    This study examines the magnitude, destinations, and determinants of mathematics and science teacher turnover. The data are from the nationally representative Schools and Staffing Survey and the Teacher Follow-Up Survey. Over the past two decades, rates of mathematics and science teacher turnover have increased but, contrary to conventional…

  17. Effects of different magnitudes of mechanical strain on Osteoblasts in vitro

    SciTech Connect

    Tang Lin; Lin Zhu; Li Yongming . E-mail: liyongming@fmmu.edu.cn

    2006-05-26

    In addition to systemic and local factors, mechanical strain plays a crucial role in bone remodeling during growth, development, and fracture healing, and especially in orthodontic tooth movement. Although many papers have been published on the effects of mechanical stress on osteoblasts or osteoblastic cells, little is known about the effects of different magnitudes of mechanical strain on such cells. In the present study, we investigated how different magnitudes of cyclic tensile strain affected osteoblasts. MC3T3-E1 osteoblastic cells were subjected to 0%, 6%, 12% or 18% elongation for 24 h using a Flexercell Strain Unit, and then the mRNA and protein expressions of osteoprotegerin (OPG) and receptor activator of nuclear factor-{kappa}B ligand (RANKL) were examined. The results showed that cyclic tensile strain induced a magnitude-dependent increase (0%, 6%, 12%, and 18%) in OPG synthesis and a concomitant decrease in RANKL mRNA expression and sRANKL release from the osteoblasts. Furthermore, the induction of OPG mRNA expression by stretching was inhibited by indomethacin or genistein, and the stretch-induced reduction of RANKL mRNA was inhibited by PD098059. These results indicate that different magnitudes of cyclic tensile strain influence the biological behavior of osteoblasts, which profoundly affects bone remodeling.

  18. Motor and non-motor error and the influence of error magnitude on brain activity.

    PubMed

    Nadig, Karin Graziella; Jäncke, Lutz; Lüchinger, Roger; Lutz, Kai

    2010-04-01

    It has been shown that frontal cortical areas increase their activity during error perception and error processing. However, it is not yet clear whether perception of motor errors is processed in the same frontal areas as perception of errors in cognitive tasks. It is also unclear whether brain activity level is influenced by the magnitude of error. For this purpose, we conducted a study in which subjects were confronted with motor and non-motor errors, and had them perform a sensorimotor transformation task in which they were likely to commit motor errors of different magnitudes (internal errors). In addition to the internally committed motor errors, non-motor errors (external errors) were added to the feedback in some trials. We found that activity in the anterior insula, inferior frontal gyrus (IFG), cerebellum, precuneus, and posterior medial frontal cortex (pMFC) correlated positively with the magnitude of external errors. The middle frontal gyrus (MFG) and the pMFC cortex correlated positively with the magnitude of the total error fed back to subjects (internal plus external). No significant positive correlation between internal error and brain activity could be detected. These results indicate that motor errors have a differential effect on brain activity compared with non-motor errors.

  19. On the Effects of Signaling Reinforcer Probability and Magnitude in Delayed Matching to Sample

    ERIC Educational Resources Information Center

    Brown, Glenn S.; White, K. Geoffrey

    2005-01-01

    Two experiments examined whether postsample signals of reinforcer probability or magnitude affected the accuracy of delayed matching to sample in pigeons. On each trial, red or green choice responses that matched red or green stimuli seen shortly before a variable retention interval were reinforced with wheat access. In Experiment 1, the…

  20. Modulation of Response Timing in ADHD, Effects of Reinforcement Valence and Magnitude

    ERIC Educational Resources Information Center

    Luman, Marjolein; Oosterlaan, Jaap; Sergeant, Joseph A.

    2008-01-01

    The present study investigated the impact of reinforcement valence and magnitude on response timing in children with ADHD. Children were required to estimate a 1-s interval, and both the median response time (response tendency) and the intrasubject-variability (response stability) were investigated. In addition, heart rate and skin conductance…

  1. Maximum earthquake magnitudes along different sections of the North Anatolian fault zone

    NASA Astrophysics Data System (ADS)

    Bohnhoff, Marco; Martínez-Garzón, Patricia; Bulut, Fatih; Stierle, Eva; Ben-Zion, Yehuda

    2016-04-01

    Constraining the maximum likely magnitude of future earthquakes on continental transform faults has fundamental consequences for the expected seismic hazard. Since the recurrence time for those earthquakes is typically longer than a century, such estimates rely primarily on well-documented historical earthquake catalogs, when available. Here we discuss the maximum observed earthquake magnitudes along different sections of the North Anatolian Fault Zone (NAFZ) in relation to the age of the fault activity, cumulative offset, slip rate and maximum length of coherent fault segments. The findings are based on a newly compiled catalog of historical earthquakes in the region, using the extensive literary sources that exist owing to the long civilization record. We find that the largest M7.8-8.0 earthquakes are exclusively observed along the older eastern part of the NAFZ that also has longer coherent fault segments. In contrast, the maximum observed events on the younger western part where the fault branches into two or more strands are smaller. No first-order relations between maximum magnitudes and fault offset or slip rates are found. The results suggest that the maximum expected earthquake magnitude in the densely populated Marmara-Istanbul region would probably not exceed M7.5. The findings are consistent with available knowledge for the San Andreas Fault and Dead Sea Transform, and can help in estimating hazard potential associated with different sections of large transform faults.

  2. Comparisons of numerical magnitudes in children with different levels of mathematical achievement. An ERP study.

    PubMed

    Gómez-Velázquez, Fabiola Reveca; Berumen, Gustavo; González-Garrido, Andrés Antonio

    2015-11-19

    The ability to map between non-symbolic and symbolic magnitude representations is crucial in the development of mathematics and this map is disturbed in children with math difficulties. In addition, positive parietal ERPs have been found to be sensitive to the number distance effect and skills solving arithmetic problems. Therefore we aimed to contrast the behavioral and ERP responses in children with different levels of mathematical achievement: low (LA), average (AA) and high (HA), while comparing symbolic and non-symbolic magnitudes. The results showed that LA children repeatedly failed when comparing magnitudes, particularly the symbolic ones. In addition, a positive correlation between correct responses while analyzing symbolic quantities and WRAT-4 scores emerged. The amplitude of N200 was significantly larger during non-symbolic comparisons. In addition, P2P amplitude was consistently smaller in LA children while comparing both symbolic and non-symbolic quantities, and correlated positively with the WRAT-4 scores. The latency of P3 seemed to be sensitive to the type of numerical comparison. The results suggest that math difficulties might be related to a more general magnitude representation problem, and that ERP are useful to study its timecourse in children with different mathematical skills.

  3. Techniques for estimating magnitude and frequency of floods on streams in Indiana

    USGS Publications Warehouse

    Glatfelter, D.R.

    1984-01-01

    A rainfall-runoff model was tlsed to synthesize long-term peak data at 11 gaged locations on small streams. Flood-frequency curves developed from the long-term synthetic data were combined with curves based on short-term observed data to provide weighted estimates of flood magnitude and frequency at the rainfall-runoff stations.

  4. Assessing Young Children's Number Magnitude Representation: A Comparison between Novel and Conventional Tasks

    ERIC Educational Resources Information Center

    Reid, Erin E.; Baroody, Arthur J.; Purpura, David J.

    2015-01-01

    Previously, researchers have relied on asking young children to plot a given number on a 0-to-10 number line to assess their mental representation of numbers 1 to 9. However, such a ("conventional") number-to-position (N-P) task may underestimate the accuracy of young children's magnitude estimates and misrepresent the nature of their…

  5. Observational validation of the chronometric cosmology: The redshift—magnitude relation for quasi-stellar objectsa

    PubMed Central

    Nicoll, J. F.; Segal, I. E.

    1978-01-01

    A statistical study is made of the redshift—magnitude relation for a recent comprehensive catalogue of quasi-stellar objects. The chronometric theory, although devoid of free parameters such as the q0 and Λ of the expansion theory, provides an excellent fit to the observed relation. The expansion theory does not provide an empirically meaningful fit. PMID:16592487

  6. Effects of Reinforcer Magnitude and Distribution on Preference for Work Schedules

    ERIC Educational Resources Information Center

    Ward-Horner, John C.; Pittenger, Alexis; Pace, Gary; Fienup, Daniel M.

    2014-01-01

    When the overall magnitude of reinforcement is matched between 2 alternative work schedules, some students prefer to complete all of their work for continuous access to a reinforcer (continuous work) rather than distributed access to a reinforcer while they work (discontinuous work). We evaluated a student's preference for continuous work by…

  7. Toddler Subtraction with Large Sets: Further Evidence for an Analog-Magnitude Representation of Number

    ERIC Educational Resources Information Center

    Slaughter, Virginia; Kamppi, Dorian; Paynter, Jessica

    2006-01-01

    Two experiments were conducted to test the hypothesis that toddlers have access to an analog-magnitude number representation that supports numerical reasoning about relatively large numbers. Three-year-olds were presented with subtraction problems in which initial set size and proportions subtracted were systematically varied. Two sets of cookies…

  8. Through Another's Eyes: The Magnitude of Our Good Fortune and Responsibility

    ERIC Educational Resources Information Center

    Stewart, Mary Grace

    2002-01-01

    In this article, the author states that teachers should look more carefully at their students and treat them as if they may someday become the future leaders of their nation and the world. Teachers need to seriously consider the magnitude of their good fortune and responsibility as teachers of those who will one day guard their nation's safety,…

  9. Standardized Magnitude Estimations of Frequency and Amount for Use in Rating Extensivity.

    ERIC Educational Resources Information Center

    Bass, Bernard M.; And Others

    Magnitude estimation was employed to find the numerical equivalents of 39 expressions of frequency ranging from never to always, and 44 expressions of amount ranging from none to all. The results were generalizable across three age-education-occupation levels and unaffected by whether ratings were an important or unimportant issue. Geometric means…

  10. Flux of optical meteors down to M sub pg = +12. [photographic absolute magnitude

    NASA Technical Reports Server (NTRS)

    Cook, A. F.; Weekes, T. C.; Williams, J. T.; Omongain, E.

    1980-01-01

    Observations of the flux of optical meteors down to photographic magnitudes of +12 are reported. The meteors were detected by photometry using a 10-m optical reflector from December 12-15, 1974, during the Geminid shower. A total of 2222 light pulses is identified as coming from meteors within the 1 deg field of view of the detector, most of which correspond to sporadic meteors traversing the detector beam at various angles and velocities and do not differ with the date, indicating that the Geminid contribution at faint luminosities is small compared to the sporadic contribution. A rate of 1.1 to 3.3 x 10 to the -12th meteors/sq cm per sec is obtained together with a power law meteor spectrum which is used to derive a relationship between cumulative meteor flux and magnitude which is linear for magnitudes from -2.4 through +12. Expressions for the cumulative flux upon the earth's atmosphere and at a test surface at 1 AU far from the earth as a function of magnitude are also obtained along with an estimate of the cumulative number density of particles.

  11. Magnitude and frequency of heat and cold waves in recent decades: the case of South America

    NASA Astrophysics Data System (ADS)

    Ceccherini, Guido; Russo, Simone; Ameztoy, Iban; Romero, Claudia Patricia; Carmona-Moreno, Cesar

    2016-03-01

    In recent decades there has been an increase in magnitude and occurrence of heat waves and a decrease of cold waves, both of which may be related to the anthropogenic influence. This study describes the extreme temperature regime of heat waves and cold waves across South America over recent years (1980-2014). Temperature records come from the Global Surface Summary of the Day (GSOD), a climatological data set produced by the National Climatic Data Center that provides records of daily maximum and minimum temperatures acquired worldwide. The magnitude of heat waves and cold waves for each GSOD station are quantified on an annual basis by means of the Heat Wave Magnitude Index and the Cold Wave Magnitude Index. Results indicate an increase in intensity and in frequency of heat waves, especially in the last 10 years. Conversely, no significant changes are detected for cold waves. In addition, the trend of the annual temperature range (i.e. yearly mean of Tmax - yearly mean of Tmin) is positive - up to 1 °C per decade - over the extratropics and negative - up to 0.5 °C per decade - over the tropics.

  12. Magnitude and frequency of heat and cold waves in recent decades: the case of South America

    NASA Astrophysics Data System (ADS)

    Ceccherini, G.; Russo, S.; Ameztoy, I.; Romero, C. P.; Carmona-Moreno, C.

    2015-12-01

    In recent decades there has been an increase in magnitude and occurrence of heat waves and a decrease of cold waves which are possibly related to the anthropogenic influence (Solomon et al., 2007). This study describes the extreme temperature regime of heat waves and cold waves across South America over recent years (1980-2014). Temperature records come from the Global Surface Summary of the Day (GSOD), a climatological dataset produced by the National Climatic Data Center that provides records of daily maximum and minimum temperatures acquired worldwide. The magnitude of heat waves and cold waves for each GSOD station are quantified on annual basis by means of the Heat Wave Magnitude Index (Russo et al., 2014) and the Cold Wave Magnitude Index (CWMI, Forzieri et al., 2015). Results indicate an increase in intensity and in frequency of heat waves, with up to 75 % more events occurring only in the last 10 years. Conversely, no significant changes are detected for cold waves. In addition, the trend of the annual temperature range (i.e., yearly mean of Tmax - yearly mean of Tmin) is positive - up to 1 °C decade-1 - over the extra-tropics and negative - up to 0.5 °C decade-1 - over the tropic. This dichotomous behaviour indicates that the annual mean of Tmax is generally increasing more than the annual mean of Tmin in the extra-tropics and vice versa in the tropics.

  13. Anchors Aweigh: A Demonstration of Cross-Modality Anchoring and Magnitude Priming

    ERIC Educational Resources Information Center

    Oppenheimer, Daniel M.; LeBoeuf, Robyn A.; Brewer, Noel T.

    2008-01-01

    Research has shown that judgments tend to assimilate to irrelevant "anchors." We extend anchoring effects to show that anchors can even operate across modalities by, apparently, priming a general sense of magnitude that is not moored to any unit or scale. An initial study showed that participants drawing long "anchor" lines made higher numerical…

  14. Earthquakes clustering based on the magnitude and the depths in Molluca Province

    SciTech Connect

    Wattimanela, H. J.; Pasaribu, U. S.; Indratno, S. W.; Puspito, A. N. T.

    2015-12-22

    In this paper, we present a model to classify the earthquakes occurred in Molluca Province. We use K-Means clustering method to classify the earthquake based on the magnitude and the depth of the earthquake. The result can be used for disaster mitigation and for designing evacuation route in Molluca Province.

  15. Increasing Magnitude "Counts" More: Asymmetrical Processing of Ordinality in 4-Month-Old Infants

    ERIC Educational Resources Information Center

    Cassia, Viola Macchi; Picozzi, Marta; Girelli, Luisa; de Hevia, Maria Dolores

    2012-01-01

    While infants' ability to discriminate quantities has been extensively studied, showing that this competence is present even in neonates, the ability to compute ordinal relations between magnitudes has received much less attention. Here we show that the ability to represent ordinal information embedded in size-based sequences is apparent at 4…

  16. Parametric Modulation of Error-Related ERP Components by the Magnitude of Visuo-Motor Mismatch

    ERIC Educational Resources Information Center

    Vocat, Roland; Pourtois, Gilles; Vuilleumier, Patrik

    2011-01-01

    Errors generate typical brain responses, characterized by two successive event-related potentials (ERP) following incorrect action: the error-related negativity (ERN) and the positivity error (Pe). However, it is unclear whether these error-related responses are sensitive to the magnitude of the error, or instead show all-or-none effects. We…

  17. Multi-dimensional self-esteem and magnitude of change in the treatment of anorexia nervosa.

    PubMed

    Collin, Paula; Karatzias, Thanos; Power, Kevin; Howard, Ruth; Grierson, David; Yellowlees, Alex

    2016-03-30

    Self-esteem improvement is one of the main targets of inpatient eating disorder programmes. The present study sought to examine multi-dimensional self-esteem and magnitude of change in eating psychopathology among adults participating in a specialist inpatient treatment programme for anorexia nervosa. A standardised assessment battery, including multi-dimensional measures of eating psychopathology and self-esteem, was completed pre- and post-treatment for 60 participants (all white Scottish female, mean age=25.63 years). Statistical analyses indicated that self-esteem improved with eating psychopathology and weight over the course of treatment, but that improvements were domain-specific and small in size. Global self-esteem was not predictive of treatment outcome. Dimensions of self-esteem at baseline (Lovability and Moral Self-approval), however, were predictive of magnitude of change in dimensions of eating psychopathology (Shape and Weight Concern). Magnitude of change in Self-Control and Lovability dimensions were predictive of magnitude of change in eating psychopathology (Global, Dietary Restraint, and Shape Concern). The results of this study demonstrate that the relationship between self-esteem and eating disorder is far from straightforward, and suggest that future research and interventions should focus less exclusively on self-esteem as a uni-dimensional psychological construct.

  18. Typical whole body vibration exposure magnitudes encountered in the open pit mining industry.

    PubMed

    Howard, Bryan; Sesek, Richard; Bloswick, Don

    2009-01-01

    According to recent research, a causal link has been established between occupational exposure to whole body vibration and an increased occurrence of low back pain. To aid in the further development of an in-house health and safety program for a large open pit mining facility interested in reducing back pain among its operators, whole body vibration magnitudes were characterized for a range of jobs. Specifically, thirty-five individual jobs from five different areas across the facility were evaluated for tri-axial acceleration levels during normal operating conditions. Tri-axial acceleration magnitudes were categorized into thirteen job groups. Job groups were ranked according to exposure and compared to the ISO 2631-1 standard for health risk assessment. Three of the thirteen job groups produced tri-axial acceleration magnitudes below the ISO 2631-1 low/moderate health caution limit for a twelve hour exposure. Six of the thirteen job groups produced exposures within the moderate health risk range. Four job groups were found to subject operators to WBV acceleration magnitudes above the moderate/high health caution limit. PMID:20037244

  19. An analysis of the magnitude and frequency of floods on Oahu, Hawaii

    USGS Publications Warehouse

    Nakahara, R.H.

    1980-01-01

    An analysis of available peak-flow data for the island of Oahu, Hawaii, was made by using multiple regression techniques which related flood-frequency data to basin and climatic characteristics for 74 gaging stations on Oahu. In the analysis, several different groupings of stations were investigated, including divisions by geographic location and size of drainage area. The grouping consisting of two leeward divisions and one windward division produced the best results. Drainage basins ranged in area from 0.03 to 45.7 square miles. Equations relating flood magnitudes of selected frequencies to basin characteristics were developed for the three divisions of Oahu. These equations can be used to estimate the magnitude and frequency of floods for any site, gaged or ungaged, for any desired recurrence interval from 2 to 100 years. Data on basin characteristics, flood magnitudes for various recurrence intervals from individual station-frequency curves, and computed flood magnitudes by use of the regression equation are tabulated to provide the needed data. (USGS)

  20. Selection Dynamics in Joint Matching to Rate and Magnitude of Reinforcement

    ERIC Educational Resources Information Center

    McDowell, J. J.; Popa, Andrei; Calvin, Nicholas T.

    2012-01-01

    Virtual organisms animated by a selectionist theory of behavior dynamics worked on concurrent random interval schedules where both the rate and magnitude of reinforcement were varied. The selectionist theory consists of a set of simple rules of selection, recombination, and mutation that act on a population of potential behaviors by means of a…

  1. Defective Number Module or Impaired Access? Numerical Magnitude Processing in First Graders with Mathematical Difficulties

    ERIC Educational Resources Information Center

    De Smedt, Bert; Gilmore, Camilla K.

    2011-01-01

    This study examined numerical magnitude processing in first graders with severe and mild forms of mathematical difficulties, children with mathematics learning disabilities (MLD) and children with low achievement (LA) in mathematics, respectively. In total, 20 children with MLD, 21 children with LA, and 41 regular achievers completed a numerical…

  2. Numerical Magnitude Representations and Individual Differences in Children's Arithmetic Strategy Use

    ERIC Educational Resources Information Center

    Vanbinst, Kiran; Ghesquiere, Pol; De Smedt, Bert

    2012-01-01

    Against the background of neuroimaging studies on how the brain processes numbers, there is now converging evidence that numerical magnitude representations are crucial for successful mathematics achievement. One major drawback of this research is that it mainly investigated mathematics performance as measured through general standardized…

  3. Hubble Space Telescope Observations of M32: The Color-Magnitude Diagram

    NASA Technical Reports Server (NTRS)

    Grillmair, C. J.; Lauer, T. R.; Worthey, G.; Faber, S. M.; Freedman, W. L.; Madore, B. F.; Ajhar, E. A.; Baum, W. A.; Holtzman, J. A.; Lynds, C. R.; O'NeilJr., E. J.; Stetson, P. B.

    1996-01-01

    We present a V--I color-magnitude diagram for a region 1'--2' the center of M32 based on Hubble Space Telescope WFPC2 images. The broad color-luminosity distribution of red giants shows that the stellar population comprises stars with a wide range in metallicity.

  4. When Is a Physical Concept Born? The Emergence of "Work" as a Magnitude of Mechanics

    ERIC Educational Resources Information Center

    Kanderakis, Nikos Emmanouil

    2010-01-01

    The physical magnitude "work" has a long history. It emerged when two different practices, performed during the whole eighteenth century, met each other. The first was theoretical, practiced by philosophers and mathematicians, and was related mainly to the "living forces" (vires vivae). The second was empirical, practiced by engineers, and was…

  5. The correlation between water production rates and visual magnitudes in comets

    NASA Technical Reports Server (NTRS)

    Jorda, L.; Crovisier, Jacques; Green, D. W. E.

    1992-01-01

    From the visual magnitudes of the International Comet Quarterly data base and the OH radio lines measured at the Nancay radio telescope, the law log Q(H2O) = 30.74 (+/-0.02) - 0.240 (+/-.003) m(sub h) is derived from a sample of 13 comets.

  6. College Students' Temporal-Magnitude Recognition Ability Associated with Durations of Scientific Changes

    ERIC Educational Resources Information Center

    Lee, Hee-Sun; Liu, Ou Lydia; Price, C. Aaron; Kendall, Amber L. M.

    2011-01-01

    The purpose of this study was to explore college students' recognition of temporal magnitudes associated with durations of scientific changes through construct validation of a 30-item instrument. We administered the instrument to 514 students from 10 higher education institutions in the United States. Among them, 419 students took the instrument…

  7. The Magnitude, Destinations, and Determinants of Mathematics and Science Teacher Turnover. CPRE Research Report # RR-66

    ERIC Educational Resources Information Center

    Ingersoll, Richard M.; May, Henry

    2010-01-01

    This study examines the magnitude, destinations, and determinants of the departures of mathematics and science teachers from public schools. The data are from the National Center for Education Statistics' nationally representative Schools and Staffing Survey and its longitudinal supplement, the Teacher Follow-up Survey. Our analyses show that…

  8. Magnitude scaling relationship from the first P-wave arrivals on Canada's west coast

    NASA Astrophysics Data System (ADS)

    Eshaghi, A.; Tiampo, K. F.

    2011-12-01

    The empirical magnitude scaling relationship from ground-motion period parameter τc is derived using vertical waveforms recorded in the Cascadia Subduction Zone (CSZ) along Canada's west coast. A high-pass filtered displacement amplitude parameter, Pd, is calculated from the initial 3 s of the P waveforms and the empirical relationship between Pd and peak ground velocity, PGV, is derived using the same data set. We selected earthquakes of M >3.0 recorded during 1996-2009 by the seismic network stations in the region operated by National Resources Canada (NRCan). In total, 90 events were selected and the vertical components of the earthquakes signals were converted to ground velocity and displacement. The displacements were filtered with a one-way Butterworth high-pass filter with a cut-off frequency of 0.075 Hz. Pd and τc are computed from the vertical seismogram components. While the average magnitude error was approximately 0.70 magnitude units when using the individual record, the error dropped to approximately 0.5 magnitude units when using the average τc for each event. In case of PGV, the average error is approximately 0.3. These relationships may be used for initial steps in establishing an earthquake early warning system for the CSZ.

  9. Discounting of Delayed Food Rewards in Pigeons and Rats: Is There a Magnitude Effect

    ERIC Educational Resources Information Center

    Green, Leonard; Myerson, Joel; Holt, Daniel D.; Slavin, John R.; Estle, Sara J.

    2004-01-01

    Temporal discounting refers to the decrease in the present, subjective value of a reward as the time to its receipt increases. Results from humans have shown that a hyperbola-like function describes the form of the discounting function when choices involve hypothetical monetary rewards. In addition, magnitude effects have been reported in which…

  10. Reversing the Signaled Magnitude Effect in Delayed Matching to Sample: Delay-Specific Remembering?

    ERIC Educational Resources Information Center

    White, K. Geoffrey; Brown, Glenn S.

    2011-01-01

    Pigeons performed a delayed matching-to-sample task in which large or small reinforcers for correct remembering were signaled during the retention interval. Accuracy was low when small reinforcers were signaled, and high when large reinforcers were signaled (the signaled magnitude effect). When the reinforcer-size cue was switched from small to…

  11. Relative Reinforcer Rates and Magnitudes Do Not Control Concurrent Choice Independently

    ERIC Educational Resources Information Center

    Elliffe, Douglas; Davison, Michael; Landon, Jason

    2008-01-01

    One assumption of the matching approach to choice is that different independent variables control choice independently of each other. We tested this assumption for reinforcer rate and magnitude in an extensive parametric experiment. Five pigeons responded for food reinforcement on switching-key concurrent variable-interval variable-interval…

  12. Paleo-earthquakes of diverse magnitude recorded at the Salt Lake site, the Haiyuan Fault, China

    NASA Astrophysics Data System (ADS)

    Liu, J.; Shao, Y.; Klinger, Y.; Xie, K.; Yuan, D.; Lei, Z.

    2013-12-01

    Paleoseismology provides routinely fundamental data for earthquake recurrence models, by revealing past ground-breaking events that stopped at different levels in layered soft sediments. Paleo-earthquakes recognized in trenches are often unknown in size, vaguely defined as surface-breaking events, but often explicitly or implicitly assumed to be similar in size when calculating earthquake recurrence interval in seismic hazard assessment of the studied fault. Here, we show data that challenge this basic underlying premise. At the Salt Lake site on the active left-lateral Haiyuan fault, northeastern Tibetan plateau, a sequence of remarkably high-resolution stratigraphy recorded at least four events since 1500 A.D., constrained by AMS C14 dating. A comparison with regional historical earthquake accounts shows that they are a mix of events of disparaging magnitudes. Except the most recent earthquake of M~8 in 1920 A.D., three earlier events, occurred in 1760 A.D., 1638 A.D., 1597 A.D. respectively, are smaller in magnitude, M~6 to M~7. Our results thus show that events order of magnitude difference in rupture length and seismic moment can be recorded at a single site, contrary to conventional definition of paleoseimic recurrence interval, which assumes simple large characteristic magnitude for recurring events.

  13. Time-delay spectrometry measurement of magnitude and phase of hydrophone response.

    PubMed

    Wear, Keith A; Gammell, Paul M; Maruvada, Subha; Liu, Yunbo; Harris, Gerald R

    2011-11-01

    A method based on time-delay spectrometry (TDS) was developed for measuring both magnitude and phase response of a hydrophone. The method was tested on several types of hydrophones used in medical ultrasound exposimetry over the range from 5 to 18 MHz. These included polyvinylidene fluoride (PVDF) spot-poled membrane, needle, and capsule designs. One needle hydrophone was designed for high-intensity focused ultrasound (HIFU) applications. The average reproducibility (after repositioning the hydrophone) of the phase measurement was 2.4°. The minimum-phase model, which implies that the phase response is equal to the inverse Hilbert transform of the natural logarithm of the magnitude response, was tested with TDS hydrophone data. Direct TDS-based measurements of hydrophone phase responses agreed well with calculations based on the minimum-phase model, with rms differences of 1.76° (PVDF spot-poled membrane hydrophone), 3.10° (PVDF capsule hydrophone), 3.43° (PVDF needle hydrophone), and 3.36° (ceramic needle hydrophone) over the range from 5 to 18 MHz. Therefore, phase responses for several types of hydrophones may be inferred from measurements of their magnitude responses. Calculation of phase response based on magnitude response using the minimumphase model is a relatively simple and practical alternative to direct measurement of phase. PMID:22083766

  14. Estimators of The Magnitude-Squared Spectrum and Methods for Incorporating SNR Uncertainty

    PubMed Central

    Lu, Yang; Loizou, Philipos C.

    2011-01-01

    Statistical estimators of the magnitude-squared spectrum are derived based on the assumption that the magnitude-squared spectrum of the noisy speech signal can be computed as the sum of the (clean) signal and noise magnitude-squared spectra. Maximum a posterior (MAP) and minimum mean square error (MMSE) estimators are derived based on a Gaussian statistical model. The gain function of the MAP estimator was found to be identical to the gain function used in the ideal binary mask (IdBM) that is widely used in computational auditory scene analysis (CASA). As such, it was binary and assumed the value of 1 if the local SNR exceeded 0 dB, and assumed the value of 0 otherwise. By modeling the local instantaneous SNR as an F-distributed random variable, soft masking methods were derived incorporating SNR uncertainty. The soft masking method, in particular, which weighted the noisy magnitude-squared spectrum by the a priori probability that the local SNR exceeds 0 dB was shown to be identical to the Wiener gain function. Results indicated that the proposed estimators yielded significantly better speech quality than the conventional MMSE spectral power estimators, in terms of yielding lower residual noise and lower speech distortion. PMID:21886543

  15. Distance and absolute magnitudes of the brightest stars in the dwarf galaxy Sextans A

    NASA Technical Reports Server (NTRS)

    Sandage, A.; Carlson, G.

    1982-01-01

    In an attempt to improve present bright star calibration, data were gathered for the brightest red and blue stars and the Cepheids in the Im V dwarf galaxy, Sextans A. On the basis of a magnitude sequence measured to V and B values of about 22 and 23, respectively, the mean magnitudes of the three brightest blue stars are V=17.98 and B=17.88. The three brightest red supergiants have V=18.09 and B=20.14. The periods and magnitudes measured for five Cepheids yield an apparent blue distance modulus of 25.67 + or - 0.2, via the P-L relation, and the mean absolute magnitudes of V=-7.56 and B=-5.53 for the red supergiants provide additional calibration of the brightest red stars as distance indicators. If Sextans A were placed at the distance of the Virgo cluster, it would appear to have a surface brightness of 23.5 mag/sq arcec. This, together with the large angular diameter, would make such a galaxy easily discoverable in the Virgo cluster by means of ground-based surveys.

  16. 48 CFR 836.204 - Disclosure of the magnitude of construction projects.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... magnitude of construction projects. 836.204 Section 836.204 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER... construction projects. In lieu of the estimated price ranges described in FAR 36.204, the contracting...

  17. 48 CFR 836.204 - Disclosure of the magnitude of construction projects.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... magnitude of construction projects. 836.204 Section 836.204 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER... construction projects. In lieu of the estimated price ranges described in FAR 36.204, the contracting...

  18. 48 CFR 836.204 - Disclosure of the magnitude of construction projects.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... magnitude of construction projects. 836.204 Section 836.204 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER... construction projects. In lieu of the estimated price ranges described in FAR 36.204, the contracting...

  19. 48 CFR 836.204 - Disclosure of the magnitude of construction projects.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... magnitude of construction projects. 836.204 Section 836.204 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER... construction projects. In lieu of the estimated price ranges described in FAR 36.204, the contracting...

  20. 48 CFR 836.204 - Disclosure of the magnitude of construction projects.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... magnitude of construction projects. 836.204 Section 836.204 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS SPECIAL CATEGORIES OF CONTRACTING CONSTRUCTION AND ARCHITECT-ENGINEER... construction projects. In lieu of the estimated price ranges described in FAR 36.204, the contracting...

  1. Does Sensitivity to Magnitude Depend on the Temporal Distribution of Reinforcement?

    ERIC Educational Resources Information Center

    Grace, Randolph C.; Bragason, Orn

    2005-01-01

    Our research addressed the question of whether sensitivity to relative reinforcer magnitude in concurrent chains depends on the distribution of reinforcer delays when the terminal-link schedules are equal. In Experiment 1, 12 pigeons responded in a two-component procedure. In both components, the initial links were concurrent variable-interval 40…

  2. Evaluating Statistical Significance Using Corrected and Uncorrected Magnitude of Effect Size Estimates.

    ERIC Educational Resources Information Center

    Snyder, Patricia; Lawson, Stephen

    Magnitude of effect measures (MEMs), when adequately understood and correctly used, are important aids for researchers who do not want to rely solely on tests of statistical significance in substantive result interpretation. The MEM tells how much of the dependent variable can be controlled, predicted, or explained by the independent variables.…

  3. Magnitude comparison extended: how lack of knowledge informs comparative judgments under uncertainty.

    PubMed

    Schweickart, Oliver; Brown, Norman R

    2014-02-01

    How do people compare quantitative attributes of real-world objects? (e.g., Which country has the higher per capita GDP, Mauritania or Nepal?). The research literature on this question is divided: Although researchers in the 1970s and 1980s assumed that a 2-stage magnitude comparison process underlies these types of judgments (Banks, 1977), more recent approaches emphasize the role of probabilistic cues and simple heuristics (Gigerenzer, Todd, & The ABC Research Group, 1999). In this article, we review the magnitude comparison literature and propose a framework for magnitude comparison under uncertainty (MaC). Predictions from this framework were tested in a choice context involving one recognized and one unrecognized object, and were contrasted with those based on the recognition heuristic (Goldstein & Gigerenzer, 2002). This was done in 2 paired-comparison studies. In both, participants were timed as they decided which of 2 countries had the higher per capita gross domestic product (GDP). Consistent with the MaC account, we found that response times (RTs) displayed a classic symbolic distance effect: RTs were inversely related to the difference between the subjective per capita GDPs of the compared countries. Furthermore, choice of the recognized country became more frequent as subjective difference increased. These results indicate that the magnitude comparison process extends to choice contexts that have previously been associated only with cue-based strategies. We end by discussing how several findings reported in the recent heuristics literature relate to the MaC framework. PMID:23317086

  4. Resting EEG in Alpha and Beta Bands Predicts Individual Differences in Attentional Blink Magnitude

    ERIC Educational Resources Information Center

    MacLean, Mary H.; Arnell, Karen M.; Cote, Kimberly A.

    2012-01-01

    Accuracy for a second target (T2) is reduced when it is presented within 500 ms of a first target (T1) in a rapid serial visual presentation (RSVP)--an attentional blink (AB). There are reliable individual differences in the magnitude of the AB. Recent evidence has shown that the attentional approach that an individual typically adopts during a…

  5. A Probabilistic Estimate of the Most Perceptible Earthquake Magnitudes in the NW Himalaya and Adjoining Regions

    NASA Astrophysics Data System (ADS)

    Yadav, R. B. S.; Koravos, G. Ch.; Tsapanos, T. M.; Vougiouka, G. E.

    2015-02-01

    NW Himalaya and its neighboring region (25°-40°N and 65°-85°E) is one of the most seismically hazardous regions in the Indian subcontinent, a region that has historically experienced large to great damaging earthquakes. In the present study, the most perceptible earthquake magnitudes, M p, are estimated for intensity I = VII, horizontal peak ground acceleration a = 300 cm/s2 and horizontal peak ground velocity v = 10 cm/s in 28 seismogenic zones using the two earthquake recurrence models of Kijko and Sellevoll (Bulletin of the Seismological Society of America 82(1):120-134 1992 ) and Gumbel's third asymptotic distribution of extremes (GIII). Both methods deal with maximum magnitudes. The earthquake perceptibility is calculated by combining earthquake recurrence models with ground motion attenuation relations at a particular level of intensity, acceleration and velocity. The estimated results reveal that the values of M p for velocity v = 10 cm/s show higher estimates than corresponding values for intensity I = VII and acceleration a = 300 cm/s2. It is also observed that differences in perceptible magnitudes calculated by the Kijko-Sellevoll method and GIII statistics show significantly high values, up to 0.7, 0.6 and 1.7 for intensity, acceleration and velocity, respectively, revealing the importance of earthquake recurrence model selection. The estimated most perceptible earthquake magnitudes, M p, in the present study vary from M W 5.1 to 7.7 in the entire zone of the study area. Results of perceptible magnitudes are also represented in the form of spatial maps in 28 seismogenic zones for the aforementioned threshold levels of intensity, acceleration and velocity, estimated from two recurrence models. The spatial maps show that the Quetta of Pakistan, the Hindukush-Pamir Himalaya, the Caucasus mountain belt and the Himalayan frontal thrust belt (Kashmir-Kangra-Uttarkashi-Chamoli regions) exhibit higher values of the most perceptible earthquake magnitudes ( M

  6. Estimating earthquake magnitudes from reported intensities in the central and eastern United States

    NASA Astrophysics Data System (ADS)

    Boyd, O. S.; Cramer, C. H.

    2011-12-01

    We develop an intensity-attenuation relation for the central and eastern United States (CEUS) and estimate the magnitudes of the 1811-1812 New Madrid, MO and 1886 Charleston, SC earthquakes. This relation incorporates an unprecedented number of intensity observations, uses a simple but sufficient form, and minimizes residuals of predicted and observed log epicentral distance rather than maximizing the likelihood of an observed intensity. We constrain the relation with the modified Mercalli intensity dataset of the National Oceanic and Atmospheric Administration along with the 'Did You Feel It?' dataset of the U.S. Geological Survey through April, 2011. We find that the new relation leads to lower magnitude estimates for the New Madrid earthquakes than many previous studies. Depending on the modified Mercalli intensity dataset used, the new relation results in estimates for the moment magnitudes of the December 16th, 1811, January 23rd, 1812, and February 7th, 1812 mainshocks and December 16th dawn aftershock of 6.6-6.9, 6.6-7.0, 6.9-7.3, and 6.4-6.8, respectively, with a magnitude uncertainty of ±0.4. We also estimate a magnitude of 6.7±0.3 for the 1886 Charleston, SC earthquake. We find a greater range of epistemic uncertainty when also accounting for multiple intensity-attenuation relations. The magnitude ranges for the December 16th, January 23rd, and February 7th mainshocks and December 16th dawn aftershock are 6.6-7.8, 6.6-7.6, 6.9-8.1, and 6.4-7.2, respectively. Relative to the 2008 national seismic hazard maps, our estimate of epistemic uncertainty increases the coefficient of variation of seismic hazard estimates by 46-60 percent for ground motions expected to be exceeded with a 2-percent probability in 50 years and by 39-48 percent for ground motions expected to be exceeded with a 10-percent probability in 50 years. The reason for the large epistemic uncertainty is due to the lack of large instrumental CEUS earthquakes, which are needed to determine the

  7. Earthquake potential and magnitude limits inferred from a geodetic strain-rate model for southern Europe

    NASA Astrophysics Data System (ADS)

    Rong, Y.; Bird, P.; Jackson, D. D.

    2016-04-01

    The project Seismic Hazard Harmonization in Europe (SHARE), completed in 2013, presents significant improvements over previous regional seismic hazard modeling efforts. The Global Strain Rate Map v2.1, sponsored by the Global Earthquake Model Foundation and built on a large set of self-consistent geodetic GPS velocities, was released in 2014. To check the SHARE seismic source models that were based mainly on historical earthquakes and active fault data, we first evaluate the SHARE historical earthquake catalogues and demonstrate that the earthquake magnitudes are acceptable. Then, we construct an earthquake potential model using the Global Strain Rate Map data. SHARE models provided parameters from which magnitude-frequency distributions can be specified for each of 437 seismic source zones covering most of Europe. Because we are interested in proposed magnitude limits, and the original zones had insufficient data for accurate estimates, we combine zones into five groups according to SHARE's estimates of maximum magnitude. Using the strain rates, we calculate tectonic moment rates for each group. Next, we infer seismicity rates from the tectonic moment rates and compare them with historical and SHARE seismicity rates. For two of the groups, the tectonic moment rates are higher than the seismic moment rates of the SHARE models. Consequently, the rates of large earthquakes forecast by the SHARE models are lower than those inferred from tectonic moment rate. In fact, the SHARE models forecast higher seismicity rates than the historical rates, which indicate that the authors of SHARE were aware of the potentially higher seismic activities in the zones. For one group, the tectonic moment rate is lower than the seismic moment rates forecast by the SHARE models. As a result, the rates of large earthquakes in that group forecast by the SHARE model are higher than those inferred from tectonic moment rate, but lower than what the historical data show. For the other two

  8. Magnitude Scaling of the early displacement for the 2007, Mw 7.8 Tocopilla sequence (Chile)

    NASA Astrophysics Data System (ADS)

    Lancieri, M.; Fuenzalida, A.; Ruiz, S.; Madariaga, R. I.

    2009-12-01

    We investigate the empirical relationships between the initial portion of P and S-phase and the final event magnitude, on the Tocopilla (Chile) event and its aftershocks. Such correlations, on which real-time magnitude estimation for seismic early warning is founded, have been widely studied on several data sets, merging earthquakes generated in different tectonic settings and recorded with very different networks. The Tocopilla (Mw 7.8) earthquake, occurred along the northern Chile seismic gap on 14 November 2007, provides, together with its aftershocks, a unique opportunity of studying a homogeneous data set in terms of tectonic environment, focal mechanism, and recording network. The preliminary analysis required to build the seismic catalogue includes the automatic identification of more than 570 aftershocks using an automatic phase detector and picker algorithm, and the subsequent location of the events through a non-linear and probabilistic code. The seismic moment (M0) has been calculated by spectral modeling of P and S waves, assuming a Brune omega-square model. This analysis also yields values for the corner frequency and quality factor. The estimated range of moment magnitude for the aftershocks sequence is [2.8 - 6.8]. The correlation between the low pass filtered peak displacement (PD) and the final magnitude has been investigated for 90 events with magnitude greater than 4. These include the main event, its larger aftershock (Mw 6.8 occurred twenty-four hours after the main shock), and seven events with magnitude greater than 5.7. The recovered relationships confirm the observations of Zollo et al. [2006, 2007] of a clear correlation between distance corrected PD and final magnitude in the magnitude range [4.0 - 7.4], when considering time windows of 4 sec of P- or 2 sec of S- wave. In contrast with the previous studies, when examining time windows of 2 sec of P-wave, we surprisingly do not observe any saturation effect for magnitudes greater than 6

  9. Detection capability of seismic network based on noise analysis and magnitude of completeness

    NASA Astrophysics Data System (ADS)

    Fischer, Tomáš; Bachura, Martin

    2014-01-01

    Assessing the detection threshold of seismic networks becomes of increased importance namely in the context of monitoring induced seismicity due to underground operations. Achieving the maximum possible sensitivity of industrial seismic monitoring is a precondition for successful control of technological procedures. Similarly, the lowest detection threshold is desirable when monitoring the natural seismic activity aimed to imaging the fault structures in 3D and to understanding the ongoing processes in the crust. We compare the application of two different methods to the data of the seismic network WEBNET that monitors the earthquake swarm activity of the West-Bohemia/Vogtland region. First, we evaluate the absolute noise level and its possible non-stationary character that results in hampering the detectability of the seismic network by producing false alarms. This is realized by the statistical analysis of the noise amplitudes using the ratio of 99 and 95 percentiles. Second, the magnitude of completeness is determined for each of the nine stations by analysing the automatic detections of an intensive swarm period from August 2011. The magnitude-frequency distributions of all detected events and events detected at individual stations are compared to determine the magnitude of completeness at a selected completeness level. The resulting magnitude of completeness M c of most of the stations varies between -0.9 and -0.5; an anomalous high M c of 0.0 is found at the most distant station, which is probably due to inadequate correction for attenuation. We find that while the absolute noise level has no significant influence to the station sensitivity, the noise stationarity correlates with station sensitivity expressed in low magnitude of completeness and vice versa. This qualifies the method of analysing the stationary character of seismic noise as an effective tool for site surveying during the seismic station deployment.

  10. Improved instrumental magnitude prediction expected from version 2 of the NASA SKY2000 master star catalog

    NASA Technical Reports Server (NTRS)

    Sande, C. B.; Brasoveanu, D.; Miller, A. C.; Home, A. T.; Tracewell, D. A.; Warren, W. H., Jr.

    1998-01-01

    The SKY2000 Master Star Catalog (MC), Version 2 and its predecessors have been designed to provide the basic astronomical input data needed for satellite acquisition and attitude determination on NASA spacecraft. Stellar positions and proper motions are the primary MC data required for operations support followed closely by the stellar brightness observed in various standard astronomical passbands. The instrumental red-magnitude prediction subsystem (REDMAG) in the MMSCAT software package computes the expected instrumental color index (CI) [sensor color correction] from an observed astronomical stellar magnitude in the MC and the characteristics of the stellar spectrum, astronomical passband, and sensor sensitivity curve. The computation is more error prone the greater the mismatch of the sensor sensitivity curve characteristics and those of the observed astronomical passbands. This paper presents the preliminary performance analysis of a typical red-sensitive CCDST during acquisition of sensor data from the two Ball CT-601 ST's onboard the Rossi X-Ray Timing Explorer (RXTE). A comparison is made of relative star positions measured in the ST FOV coordinate system with the expected results computed from the recently released Tycho Catalogue. The comparison is repeated for a group of observed stars with nearby, bright neighbors in order to determine the tracker behavior in the presence of an interfering, near neighbor (NN). The results of this analysis will be used to help define a new photoelectric photometric instrumental sensor magnitude system (S) that is based on several thousand bright star magnitudes observed with the PXTE ST's. This new system will be implemented in Version 2 of the SKY2000 MC to provide improved predicted magnitudes in the mission run catalogs.

  11. Recent shifts in the occurrence, cause, and magnitude of animal mass mortality events

    PubMed Central

    Fey, Samuel B.; Siepielski, Adam M.; Nusslé, Sébastien; Cervantes-Yoshida, Kristina; Hwan, Jason L.; Huber, Eric R.; Fey, Maxfield J.; Catenazzi, Alessandro; Carlson, Stephanie M.

    2015-01-01

    Mass mortality events (MMEs) are rapidly occurring catastrophic demographic events that punctuate background mortality levels. Individual MMEs are staggering in their observed magnitude: removing more than 90% of a population, resulting in the death of more than a billion individuals, or producing 700 million tons of dead biomass in a single event. Despite extensive documentation of individual MMEs, we have no understanding of the major features characterizing the occurrence and magnitude of MMEs, their causes, or trends through time. Thus, no framework exists for contextualizing MMEs in the wake of ongoing global and regional perturbations to natural systems. Here we present an analysis of 727 published MMEs from across the globe, affecting 2,407 animal populations. We show that the magnitude of MMEs has been intensifying for birds, fishes, and marine invertebrates; invariant for mammals; and decreasing for reptiles and amphibians. These shifts in magnitude proved robust when we accounted for an increase in the occurrence of MMEs since 1940. However, it remains unclear whether the increase in the occurrence of MMEs represents a true pattern or simply a perceived increase. Regardless, the increase in MMEs appears to be associated with a rise in disease emergence, biotoxicity, and events produced by multiple interacting stressors, yet temporal trends in MME causes varied among taxa and may be associated with increased detectability. In addition, MMEs with the largest magnitudes were those that resulted from multiple stressors, starvation, and disease. These results advance our understanding of rare demographic processes and their relationship to global and regional perturbations to natural systems. PMID:25583498

  12. Magnitude-recurrence statistics for stratabound fracture networks in layered media

    NASA Astrophysics Data System (ADS)

    Eaton, David; Davidsen, Joern

    2014-05-01

    Variants of the Gutenberg-Richter (G-R) relation, which express scale-independent behavior of earthquakes over a range of values, are almost universally used to describe magnitude-recurrence statistics for microseismic observations. The b value, which is the slope derived from classic G-R plots, is a particularly important parameter that effectively measures the abundance of large-magnitude events relative to small events. Hydraulic fracture monitoring programs often yield apparent b values of 2.0 or greater. These values are exceptionally high compared to earthquake fault sysems, which typically exhibit b values close to 1.0. In some reports, a sudden reduction in b value during treatment has been attributed to unintended activation of a pre-existing fault. An alternative model is developed here to describe magnitude statistics of microseismic events that occur on steeply dipping to vertical fracture surfaces in horizontally layered media. Termination of fractures at mechanical layer boundaries imposes a size-dependent scaling relationship and results in a stratabound fracture networks, which are well described in a number of field studies. In the case of constant stress drop, microseismic magnitude distributions will mimic bed-thickness distributions under these circumstances. A lognormal distribution of mechanical bed thickness, which provides a good fit for three examples considered here from various parts of North America, leads asymptotically to a Gaussian distribution of microseismic magnitudes that readily explains apparent observed b values of close to 2.0. This model is consistent with a sudden reduction in b value arising from uninended triggering of a pre-existing fault, and also implies that subtle changes in b value during a treatment program may be indicative of spatial variations in reservoir facies.

  13. Pitch-angle Scattering of Energetic Charged Particles in Nearly Constant Magnitude Magnetic Turbulence

    NASA Astrophysics Data System (ADS)

    Sun, P.; Jokipii, J. R.; Giacalone, J.

    2016-08-01

    We use a method developed by Roberts that optimizes the phase angles of an ensemble of plane waves with amplitudes determined from a Kolmogorov-like power spectrum, to construct magnetic field vector fluctuations having nearly constant magnitude and large variances in its components. This is a representation of the turbulent magnetic field consistent with that observed in the solar wind. Charged-particle pitch-angle diffusion coefficients are determined by integrating the equations of motion for a large number of charged particles moving under the influence of forces from our predefined magnetic field. We tested different cases by varying the kinetic energy of the particles (E p) and the turbulent magnetic field variance ({σ }B2). For each combination of E p and {σ }B2, we tested three different models: (1) the so-called “slab” model, where the turbulent magnetic field depends on only one spatial coordinate and has significant fluctuations in its magnitude (b=\\sqrt{δ {B}x2(z)+δ {B}y2(z)+{B}02}) (2) the slab model optimized with nearly constant magnitude b; and (3) the slab model turbulent magnetic field with nearly constant magnitude plus a “variance-conserving” adjustment. In the last case, this model attempts to conserve the variance of the turbulent components ({σ }{Bx}2+{σ }{By}2), which is found to decrease during the optimization with nearly constant magnitude. We found that there is little or no effect on the pitch-angle diffusion coefficient {D}μ μ between models 1 and 2. However, the result from model 3 is significantly different. We also introduce a new method to accurately determine the pitch-angle diffusion coefficients as a function of μ.

  14. Nonlinear magnitude and linear phase behaviors of T2* imaging: theoretical approximation and Monte Carlo simulation.

    PubMed

    Chen, Zikuan; Calhoun, Vince

    2015-05-01

    The underlying source of brain imaging by T2*-weighted magnetic resonance imaging (T2*MRI) is the intracranial inhomogeneous tissue magnetic susceptibility (denoted by χ) that causes an inhomogeneous field map (via magnetization) in a main field. By decomposing T2*MRI into two steps, we understand that the 1st step from a χ source to a field map is a linear but non-isomorphic spatial mapping, and the 2nd step from the field map to a T2* image is a nonlinear mapping due to the trigonometric behavior of spin precession signals. The magnitude and phase calculations from a complex T2* image introduce additional nonlinearities. In this report, we look into the magnitude and phase behaviors of a T2* image (signal) by theoretical approximation and Monte Carlo simulation. We perform the 1st-order Taylor expansion on intravoxel dephasing formula of a T2* signal and show that the T2* magnitude is a quadratic mapping of the field map and T2* phase is a linear isomorphic mapping. By Monte Carlo simulation of T2*MRI for a span of echo times (with B0=3T and TE=[0,120] ms), we first confirm the quadratic magnitude and linear phase behaviors in small phase angle regime (via TE <30ms), and then provide more general magnitude and phase nonlinear behaviors in large phase angle scenarios (via TE >30ms). By solving the inverse problem of T2*MRI, we demonstrate χ tomography and conclude that the χ source can be reliably reconstructed from a T2* phase image in a small phase angle regime. PMID:25623809

  15. Estudio del CH interestelar

    NASA Astrophysics Data System (ADS)

    Olano, C.; Lemarchand, G.; Sanz, A. J.; Bava, J. A.

    El objetivo principal de este proyecto consiste en el estudio de la distribución y abundancia del CH en nubes interestelares a través de la observación de las líneas hiperfinas del CH en 3,3 GHz. El CH es una molécula de amplia distribución en el espacio interestelar y una de las pocas especies que han sido observadas tanto con técnicas de radio como ópticas. Desde el punto de vista tecnológico se ha desarrollado un cabezal de receptor que permitirá la realización de observaciones polarimétricas en la frecuencia de 3,3 GHz, con una temperatura del sistema de 60 K y un ancho de banda de 140 MHz, y que será instalado en el foco primario de la antena parabólica del IAR. El cabezal del receptor es capaz de detectar señales polarizadas, separando las componentes de polarización circular derecha e izquierda. Para tal fin el cabezal consta de dos ramas receptoras que amplificarán la señal y la trasladarán a una frecuencia más baja (frecuencia intermedia), permitiendo de esa forma un mejor transporte de la señal a la sala de control para su posterior procesamiento. El receptor además de tener características polarimétricas, podrá ser usado en el continuo y en la línea, utilizando las ventajas observacionales y de procesamiento de señal que actualmente posee el IAR.

  16. Comparing the Magnitude of Two Fractions with Common Components: Which Representations Are Used by 10- and 12-Year-Olds?

    ERIC Educational Resources Information Center

    Meert, Gaelle; Gregoire, Jacques; Noel, Marie-Pascale

    2010-01-01

    This study tested whether 10- and 12-year-olds who can correctly compare the magnitudes of fractions with common components access the magnitudes of the whole fractions rather than only compare the magnitudes of their components. Time for comparing two fractions was predicted by the numerical distance between the whole fractions, suggesting an…

  17. The Del Rio ataxite, Texas

    NASA Technical Reports Server (NTRS)

    Henderson, E. P.; King, E. A.

    1977-01-01

    Basic data are presented on the Del Rio, Nordheim, and Monahans ataxites found in Texas. Results are reported for bulk-chemistry analysis, metallographic observations, and electron-microprobe analysis of the Del Rio meteorite. It is shown that Del Rio is distinctly different from the other two ataxites in terms of nickel, phosphorous, and carbon content, and is composed of at least three coarse grains in different crystallographic orientations. All the kamacite in Del Rio is found to have transformation structures that are probable shock products, and minor inclusions of daubreelite, schreibersite, and troilite are observed. It is concluded that Del Rio was apparently mildly shocked prior to its fall.

  18. Maximum Magnitude in Relation to Mapped Fault Length and Fault Rupture

    NASA Astrophysics Data System (ADS)

    Black, N.; Jackson, D.; Rockwell, T.

    2004-12-01

    Earthquake hazard zones are highlighted using known fault locations and an estimate of the fault's maximum magnitude earthquake. Magnitude limits are commonly determined from fault geometry, which is dependent on fault length. Over the past 30 years it has become apparent that fault length is often poorly constrained and that a single event can rupture across several individual fault segments. In this study fault geometries are analyzed before and after several moderate to large magnitude earthquakes to determine how well fault length can accurately assess seismic hazard. Estimates of future earthquake magnitudes are often inferred from prior determinations of fault length, but use magnitude regressions based on rupture length. However, rupture length is not always limited to the previously estimated fault length or contained on a single fault. Therefore, the maximum magnitude for a fault may be underestimated, unless the geometry and segmentation of faulting is completely understood. This study examines whether rupture/fault length can be used to accurately predict the maximum magnitude for a given fault. We examine earthquakes greater than 6.0 that occurred after 1970 in Southern California. Geologic maps, fault evaluation reports, and aerial photos that existed prior to these earthquakes are used to obtain the pre-earthquake fault lengths. Pre-earthquake fault lengths are compared with rupture lengths to determine: 1) if fault lengths are the same before and after the ruptures and 2) to constrain the geology and geometry of ruptures that propagated beyond the originally recognized endpoints of a mapped fault. The ruptures examined in this study typically follow one of the following models. The ruptures are either: 1) contained within the dimensions of the original fault trace, 2) break through one or both end points of the originally mapped fault trace, or 3) break through multiple faults, connecting segments into one large fault line. No rupture simply broke a

  19. Causality between expansion of seismic cloud and maximum magnitude of induced seismicity in geothermal field

    NASA Astrophysics Data System (ADS)

    Mukuhira, Yusuke; Asanuma, Hiroshi; Ito, Takatoshi; Häring, Markus

    2016-04-01

    Occurrence of induced seismicity with large magnitude is critical environmental issues associated with fluid injection for shale gas/oil extraction, waste water disposal, carbon capture and storage, and engineered geothermal systems (EGS). Studies for prediction of the hazardous seismicity and risk assessment of induced seismicity has been activated recently. Many of these studies are based on the seismological statistics and these models use the information of the occurrence time and event magnitude. We have originally developed physics based model named "possible seismic moment model" to evaluate seismic activity and assess seismic moment which can be ready to release. This model is totally based on microseismic information of occurrence time, hypocenter location and magnitude (seismic moment). This model assumes existence of representative parameter having physical meaning that release-able seismic moment per rock volume (seismic moment density) at given field. Seismic moment density is to be estimated from microseismic distribution and their seismic moment. In addition to this, stimulated rock volume is also inferred by progress of microseismic cloud at given time and this quantity can be interpreted as the rock volume which can release seismic energy due to weakening effect of normal stress by injected fluid. Product of these two parameters (equation (1)) provide possible seismic moment which can be released from current stimulated zone as a model output. Difference between output of this model and observed cumulative seismic moment corresponds the seismic moment which will be released in future, based on current stimulation conditions. This value can be translated into possible maximum magnitude of induced seismicity in future. As this way, possible seismic moment can be used to have feedback to hydraulic stimulation operation in real time as an index which can be interpreted easily and intuitively. Possible seismic moment is defined as equation (1), where D

  20. Locations and magnitudes of earthquakes in Central Asia from seismic intensity data

    NASA Astrophysics Data System (ADS)

    Bindi, D.; Parolai, S.; Gómez-Capera, A.; Locati, M.; Kalmetyeva, Z.; Mikhailova, N.

    2014-01-01

    We apply the Bakun and Wentworth ( Bull Seism Soc Am 87:1502-1521, 1997) method to determine the location and magnitude of earthquakes occurred in Central Asia using MSK-64 intensity assignments. The attenuation model previously derived and validated by Bindi et al. ( Geophys J Int, 2013) is used to analyse 21 earthquakes that occurred over the period 1885-1964, and the estimated locations and magnitudes are compared to values available in literature. Bootstrap analyses are performed to estimate the confidence intervals of the intensity magnitudes, as well as to quantify the location uncertainty. The analyses of seven significant earthquakes for the hazard assessment are presented in detail, including three large historical earthquakes that struck the northern Tien-Shan between the end of the nineteenth and the beginning of the twentieth centuries: the 1887, M 7.3 Verny, the 1889, M 8.3 Chilik and the 1911, M 8.2 Kemin earthquakes. Regarding the 1911, Kemin earthquake the magnitude values estimated from intensity data are lower (i.e. MILH = 7.8 and MIW = 7.6 considering surface wave and moment magnitude, respectively) than the value M = 8.2 listed in the considered catalog. These values are more in agreement with the value M S = 7.8 revised by Abe and Noguchi ( Phys Earth Planet In, 33:1-11, 1983b) for the surface wave magnitude. For the Kemin earthquake, the distribution of the bootstrap solutions for the intensity centre reveal two minima, indicating that the distribution of intensity assignments do not constrain a unique solution. This is in agreement with the complex source rupture history of the Kemin earthquake, which involved several fault segments with different strike orientations, dipping angles and focal mechanisms (e.g. Delvaux et al. in Russ Geol Geophys 42:1167-1177, 2001; Arrowsmith et al. in Eos Trans Am Geophys Union 86(52), 2005). Two possible locations for the intensity centre are obtained. The first is located on the easternmost sub-faults (i

  1. Investigations Into Early Magnitude Estimation From Predominant Period, Using Synthetic Rupture Models

    NASA Astrophysics Data System (ADS)

    Hildyard, M.; Rietbrock, A.

    2007-12-01

    Considerable interest has been shown in a method for estimating predominant period in the time domain (TpMax), first proposed by Nakamura (1988) and currently being developed for other early warning systems (e.g. Lockman and Allen, BSSA, 2005). Issues still exist as to the causes of the scatter evident in empirical work, and how effective the method is for characterising large events whose time to rupture is longer than the few seconds desired to estimate the magnitude. Our work on applying this method to an aftershock dataset motivated us to investigate the method through the use of synthetic rupture models. The rupture model we use prescribes a stress-drop with a prescribed rise-time over a small patch of the fault surface. This stress-drop is propagated to other patches of the fault according to a prescribed rupture rate. The same finite difference model geometry and fault patch size was then used to model events ranging from magnitude 3.7 to 7.2. Moment Magnitude was calculated directly by integrating the resultant slip on the fault, and TpMax was calculated from seismograms recorded on surface 50 km from the centre of the fault. The initial modelling used a homogenous stress drop, rise-time, and rupture rate. A dataset of 165 events, showed a significant increasing relationship between the TpMax calculation and magnitude. Isolating similar events initiating at the same point on the fault, gave a near straight-line trend. Scatter in the relationship is shown to result from variations in the position, initiation point, stress drop, rise time, and rupture velocity. Low frequency filtering was found to significantly affect the TpMax calculations and trends. Without filtering, the relationship saturated from just after magnitude 6, as the time to rupture becomes longer than the window used to calculate TpMax. However, low frequency filtering actually reduces the time to reach a maximum in the calculation, and this can cause the increasing trend to continue into

  2. Magnitudes and Moment-Duration Scaling of Low-Frequency Earthquakes Beneath Southern Vancouver Island

    NASA Astrophysics Data System (ADS)

    Bostock, M. G.; Thomas, A.; Rubin, A. M.; Savard, G.; Chuang, L. Y.

    2015-12-01

    We employ 130 low-frequency-earthquake (LFE) templates representing tremor sources on the plate boundary below southern Vancouver Island to examine LFE magnitudes. Each template is assembled from 100's to 1000's of individual LFEs, representing over 300,000 independent detections from major episodic-tremor-and- slip (ETS) events between 2003 and 2013. Template displacement waveforms for direct P- and S-waves at near epicentral distances are remarkably simple at many stations, approaching the zero-phase, single pulse expected for a point dislocation source in a homogeneous medium. High spatio-temporal precision of template match-filtered detections facilitates precise alignment of individual LFE detections and analysis of waveforms. Upon correction for 1-D geometrical spreading, attenuation, free-surface magnification and radiation pattern, we solve a large, sparse linear system for 3-D path corrections and LFE magnitudes for all detections corresponding to a single ETS template. The spatio-temporal distribution of magnitudes indicates that typically half the total moment release occurs within the first 12-24 hours of LFE activity during an ETS episode when tidal sensitity is low. The remainder is released in bursts over several days, particularly as spatially extensive RTRs, during which tidal sensitivity is high. RTR's are characterized by large magnitude LFEs, and are most strongly expressed in the updip portions of the ETS transition zone and less organized at downdip levels. LFE magnitude-frequency relations are better described by power-law than exponential distributions although they exhibit very high b-values ≥ 6. We examine LFE moment-duration scaling by generating templates using detections for limiting magnitude ranges MW<1.5, MW≥ 2.0. LFE duration displays a weaker dependence upon moment than expected for self-similarity, suggesting that LFE asperities are limited in dimension and that moment variation is dominated by slip. This behaviour implies

  3. A new dataset of Wood Anderson magnitude from the Trieste (Italy) seismic station

    NASA Astrophysics Data System (ADS)

    Sandron, Denis; Gentile, G. Francesco; Gentili, Stefania; Rebez, Alessandro; Santulin, Marco; Slejko, Dario

    2014-05-01

    The standard torsion Wood Anderson (WA) seismograph owes its fame to the fact that historically it has been used for the definition of the magnitude of an earthquake (Richter, 1935). With the progress of the technology, digital broadband (BB) seismographs replaced it. However, for historical consistency and homogeneity with the old seismic catalogues, it is still important continuing to compute the so called Wood Anderson magnitude. In order to evaluate WA magnitude, the synthetic seismograms WA equivalent are simulated convolving the waveforms recorded by a BB instrument with a suitable transfer function. The value of static magnification that should be applied in order to simulate correctly the WA instrument is debated. The original WA instrument in Trieste operated from 1971 to 1992 and the WA magnitude (MAW) estimates were regularly reported in the seismic station bulletins. The calculation of the local magnitude was performed following the Richter's formula (Richter, 1935), using the table of corrections factor unmodified from those calibrated for California and without station correction applied (Finetti, 1972). However, the WA amplitudes were computed as vector sum rather than arithmetic average of the horizontal components, resulting in a systematic overestimation of approximately 0.25, depending on the azimuth. In this work, we have retrieved the E-W and N-S components of the original recordings and re-computed MAW according to the original Richter (1935) formula. In 1992, the WA recording were stopped, due to the long time required for the daily development of the photographic paper, the costs of the photographic paper and the progress of the technology. After a decade of interruption, the WA was recovered and modernized by replacing the recording on photographic paper with an electronic device and it continues presently to record earthquakes. The E-W and N-S components records were memorized, but not published till now. Since 2004, next to the WA (few

  4. The magnitude and significance of Ca2+ domains for release of neurotransmitter.

    PubMed

    Aharon, S; Parnas, H; Parnas, I

    1994-11-01

    It is now widely accepted that localized high concentrations of Ca2+ (Ca2+ domains) play a major role in controlling the time course of neurotransmitter release. In the present work we calculate the magnitude and the time course of Ca2+ domains that evolve in the vicinity of a Ca2+ channel and an adjacent release site. In the calculations we consider a accurately dimensioned Ca2+ channel. Moreover, the Ca2+ current is continuously adjusted with regard to the accumulated intracellular Ca2+ and, in addition, endogenous buffers are considered. The calculations, carried out by the software FIDAP, based on finite element method, show that the Ca2+ concentrations achieved near the release sites are significantly lower than claimed by other investigators. Furthermore, we present arguments indicating that the Ca2+ domains, regardless of their magnitude, do not play a role in controlling the time course of release of neurotransmitter.

  5. Magnitude of flood flows for selected annual exceedance probabilities in Rhode Island through 2010

    USGS Publications Warehouse

    Zarriello, Phillip J.; Ahearn, Elizabeth A.; Levin, Sara B.

    2012-01-01

    Heavy persistent rains from late February through March 2010 caused severe widespread flooding in Rhode Island that set or nearly set record flows and water levels at many long-term streamgages in the State. In response, the U.S. Geological Survey, in partnership with the Federal Emergency Management Agency, conducted a study to update estimates of flood magnitudes at streamgages and regional equations for estimating flood flows at ungaged locations. This report provides information needed for flood plain management, transportation infrastructure design, flood insurance studies, and other purposes that can help minimize future flood damages and risks. The magnitudes of floods were determined from the annual peak flows at 43 streamgages in Rhode Island (20 sites), Connecticut (14 sites), and Massachusetts (9 sites) using the standard Bulletin 17B log-Pearson type III method and a modification of this method called the expected moments algorithm (EMA) for 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probability (AEP) floods. Annual-peak flows were analyzed for the period of record through the 2010 water year; however, records were extended at 23 streamgages using the maintenance of variance extension (MOVE) procedure to best represent the longest period possible for determining the generalized skew and flood magnitudes. Generalized least square regression equations were developed from the flood quantiles computed at 41 streamgages (2 streamgages in Rhode Island with reported flood quantiles were not used in the regional regression because of regulation or redundancy) and their respective basin characteristics to estimate magnitude of floods at ungaged sites. Of 55 basin characteristics evaluated as potential explanatory variables, 3 were statistically significant—drainage area, stream density, and basin storage. The pseudo-coefficient of determination (pseudo-R2) indicates these three explanatory variables explain 95 to 96 percent of the variance

  6. Source time function properties indicate a strain drop independent of earthquake depth and magnitude.

    PubMed

    Vallée, Martin

    2013-01-01

    The movement of tectonic plates leads to strain build-up in the Earth, which can be released during earthquakes when one side of a seismic fault suddenly slips with respect to the other. The amount of seismic strain release (or 'strain drop') is thus a direct measurement of a basic earthquake property, that is, the ratio of seismic slip over the dimension of the ruptured fault. Here the analysis of a new global catalogue, containing ~1,700 earthquakes with magnitude larger than 6, suggests that strain drop is independent of earthquake depth and magnitude. This invariance implies that deep earthquakes are even more similar to their shallow counterparts than previously thought, a puzzling finding as shallow and deep earthquakes are believed to originate from different physical mechanisms. More practically, this property contributes to our ability to predict the damaging waves generated by future earthquakes. PMID:24126256

  7. Magnitude estimation scaling of annoyance in response to rock music: effects of sex and listeners' preference.

    PubMed

    Fucci, D; Petrosino, L; Hallowell, B; Andra, L; Wilcox, C

    1997-04-01

    The present study parallels an earlier one Fucci, Petrosino, and Banks in 1994 concerned with sex and listeners' preference effects on magnitude estimation scaling of rock music. The difference between the two studies is that the subjects in 1994 were asked to scale "loudness" while the present subjects were asked to scale "annoyance." The prior results and those of the present study were different, i.e., the women's preference appeared influential in the magnitude estimation scaling of rock music previously but here the men's preference appeared influential. If subjects are instructed to judge the annoyance of an auditory signal, they may respond differently than if asked to judge its loudness. Judgments of annoyance appear to be more context dependent whereas loudness judgments may reflect a perceptual process more closely related to physical aspects of the signal.

  8. The effect of preference for rock music on magnitude-estimation scaling behavior in young adults.

    PubMed

    Fucci, D; Harris, D; Petrosino, L; Banks, M

    1993-06-01

    The purpose of the present study was to examine the effect of preference for rock music on magnitude-estimation scaling behavior in young adults. Two groups of young adults, 20 who liked rock music and 20 who did not like rock music, were tested. Subjects were instructed to assign numerical values to a random series of nine suprathreshold intensity levels of a 10-second sample of rock music. Analysis indicated that there was a difference in performance by the two groups of subjects on the magnitude-estimation scaling task. The subjects who liked rock music provided significantly lower mean numerical responses than the subjects who did not like rock music for all nine suprathreshold intensities.

  9. Systematic Underestimation of Earthquake Magnitudes from Large Intracontinental Reverse Faults: Historical Ruptures Break Across Segment Boundaries

    NASA Technical Reports Server (NTRS)

    Rubin, C. M.

    1996-01-01

    Because most large-magnitude earthquakes along reverse faults have such irregular and complicated rupture patterns, reverse-fault segments defined on the basis of geometry alone may not be very useful for estimating sizes of future seismic sources. Most modern large ruptures of historical earthquakes generated by intracontinental reverse faults have involved geometrically complex rupture patterns. Ruptures across surficial discontinuities and complexities such as stepovers and cross-faults are common. Specifically, segment boundaries defined on the basis of discontinuities in surficial fault traces, pronounced changes in the geomorphology along strike, or the intersection of active faults commonly have not proven to be major impediments to rupture. Assuming that the seismic rupture will initiate and terminate at adjacent major geometric irregularities will commonly lead to underestimation of magnitudes of future large earthquakes.

  10. Enhancing the magnitude spectrum of speech features for robust speech recognition

    NASA Astrophysics Data System (ADS)

    Hung, Jeih-weih; Fan, Hao-teng; Tu, Wen-hsiang

    2012-12-01

    In this article, we present an effective compensation scheme to improve noise robustness for the spectra of speech signals. In this compensation scheme, called magnitude spectrum enhancement (MSE), a voice activity detection (VAD) process is performed on the frame sequence of the utterance. The magnitude spectra of non-speech frames are then reduced while those of speech frames are amplified. In experiments conducted on the Aurora-2 noisy digits database, MSE achieves an error reduction rate of nearly 42% relative to baseline processing. This method outperforms well-known spectral-domain speech enhancement techniques, including spectral subtraction (SS) and Wiener filtering (WF). In addition, the proposed MSE can be integrated with cepstral-domain robustness methods, such as mean and variance normalization (MVN) and histogram normalization (HEQ), to achieve further improvements in recognition accuracy under noise-corrupted environments.

  11. Observational validation of the chronometric cosmology: I. Preliminaries and the redshift-magnitude relation

    PubMed Central

    Segal, I. E.

    1975-01-01

    Results of comprehensive observational tests of the cosmological theory proposed by Segal in 1972 are summarized in this and succeeding notes. Within a framework of natural and general causality and symmetry considerations, the theory is mathematically essentially unique. It implies definite relations between directly observed quantities (redshift, apparent magnitude and diameter, number counts, and the like) which are entirely free of adjustable parameters, such as the q0 and Λ of general relativistic cosmologies. Rigorous statistical analysis of large (≳100) or systematically defined samples of galaxies or quasars accepts these relations at substantial probability levels. Note I establishes uniform statistical procedures and compares the redshift—magnitude relations of major samples with the theoretical relations of the present and expansion theories. PMID:16592255

  12. Probabilistic tsunami hazard assessment for the Makran region with focus on maximum magnitude assumption

    NASA Astrophysics Data System (ADS)

    Hoechner, A.; Babeyko, A. Y.; Zamora, N.

    2015-09-01

    Despite having been rather seismically quiescent for the last decades, the Makran subduction zone is capable of hosting destructive earthquakes and tsunami. In particular, the well-known thrust event in 1945 (Balochistan earthquake) led to about 4000 casualties. Nowadays, the coastal regions are more densely populated and vulnerable to similar events. Furthermore, some recent publications discuss rare but significantly larger events at the Makran subduction zone as possible scenarios. We analyze the instrumental and historical seismicity at the subduction plate interface and generate various synthetic earthquake catalogs spanning 300 000 years with varying magnitude-frequency relations. For every event in the catalogs we compute estimated tsunami heights and present the resulting tsunami hazard along the coasts of Pakistan, Iran and Oman in the form of probabilistic tsunami hazard curves. We show how the hazard results depend on variation of the Gutenberg-Richter parameters and especially maximum magnitude assumption.

  13. Uvby-beta photometry of visual double stars - Absolute magnitudes of intrinsically bright stars

    NASA Astrophysics Data System (ADS)

    Olsen, E. H.

    1982-05-01

    Individual absolute visual magnitudes M(v) are derived for intrinsically bright stars and evolved stars. The results are collected for 106 objects believed to be members of binary systems. uvby-beta photometry was empirically calibrated in terms of M(v) for main sequence stars and photoelectrically determined apparent magnitudes. The derived M(v) values are not significantly different from those stated in the Wilson catalogue (1976). Binary systems with main sequence primaries and secondary components off the main sequence were also investigated. Several systems in which at least one component may be in the pre-main sequence contraction stage are pointed out. A wide variety of comments and derived data are given individually for 136 double stars, including metallicities, distance moduli, and masses.

  14. Probabilistic tsunami hazard assessment for the Makran region with focus on maximum magnitude assumption

    NASA Astrophysics Data System (ADS)

    Hoechner, Andreas; Babeyko, Andrey Y.; Zamora, Natalia

    2016-06-01

    Despite having been rather seismically quiescent for the last decades, the Makran subduction zone is capable of hosting destructive earthquakes and tsunami. In particular, the well-known thrust event in 1945 (Balochistan earthquake) led to about 4000 casualties. Nowadays, the coastal regions are more densely populated and vulnerable to similar events. Furthermore, some recent publications discuss rare but significantly larger events at the Makran subduction zone as possible scenarios. We analyze the instrumental and historical seismicity at the subduction plate interface and generate various synthetic earthquake catalogs spanning 300 000 years with varying magnitude-frequency relations. For every event in the catalogs we compute estimated tsunami heights and present the resulting tsunami hazard along the coasts of Pakistan, Iran and Oman in the form of probabilistic tsunami hazard curves. We show how the hazard results depend on variation of the Gutenberg-Richter parameters and especially maximum magnitude assumption.

  15. Working memory capacity, intelligence, and the magnitude of the attentional blink revisited.

    PubMed

    Martens, Sander; Johnson, Addie

    2009-01-01

    The attentional blink (AB) is a well-established phenomenon in the study of attention. This deficit in reporting the second of two targets presented in rapid serial visual presentation when it occurs 200-500 ms after the first is considered to reflect a fundamental limitation in attentional processing. However, we recently reported that some individuals do not show an AB, and presented psychophysiological evidence that target processing differs between blinkers and non-blinkers. One possibility is that non-blinkers may have a larger WM capacity, allowing better attentional control. Here we explore the relation between the magnitude of the AB, general intelligence, and different measures of working memory (WM) and short-term memory (STM) capacity. Surprisingly, no correlation was found between memory capacity measures and AB magnitude, raising doubts about the generalizability of earlier findings of such a relationship.

  16. The impact of fraction magnitude knowledge on algebra performance and learning.

    PubMed

    Booth, Julie L; Newton, Kristie J; Twiss-Garrity, Laura K

    2014-02-01

    Knowledge of fractions is thought to be crucial for success with algebra, but empirical evidence supporting this conjecture is just beginning to emerge. In the current study, Algebra 1 students completed magnitude estimation tasks on three scales (0-1 [fractions], 0-1,000,000, and 0-62,571) just before beginning their unit on equation solving. Results indicated that fraction magnitude knowledge, and not whole number knowledge, was especially related to students' pretest knowledge of equation solving and encoding of equation features. Pretest fraction knowledge was also predictive of students' improvement in equation solving and equation encoding skills. Students' placement of unit fractions (e.g., those with a numerator of 1) was not especially useful for predicting algebra performance and learning in this population. Placement of non-unit fractions was more predictive, suggesting that proportional reasoning skills might be an important link between fraction knowledge and learning algebra.

  17. The Modulation of Operant Variation by the Probability, Magnitude, and Delay of Reinforcement

    PubMed Central

    Stahlman, W. David; Blaisdell, Aaron P.

    2011-01-01

    Recent studies have demonstrated that the expectation of reward delivery has an inverse relationship with operant behavioral variation (e.g., Stahlman, Roberts, & Blaisdell, 2010). Research thus far has largely focused on one aspect of reinforcement – the likelihood of food delivery. In two experiments with pigeons, we examined the effect of two other aspects of reinforcement: the magnitude of the reward and the temporal delay between the operant response and outcome delivery. In the first experiment, we found that a large reward magnitude resulted in reduced spatiotemporal variation in pigeons’ pecking behavior. In the second experiment, we found that a 4-s delay between response-dependent trial termination and reward delivery increased variation in behavior. These results indicate that multiple dimensions of the reinforcer modulate operant response variation. PMID:21731111

  18. Beyond Power Calculations: Assessing Type S (Sign) and Type M (Magnitude) Errors.

    PubMed

    Gelman, Andrew; Carlin, John

    2014-11-01

    Statistical power analysis provides the conventional approach to assess error rates when designing a research study. However, power analysis is flawed in that a narrow emphasis on statistical significance is placed as the primary focus of study design. In noisy, small-sample settings, statistically significant results can often be misleading. To help researchers address this problem in the context of their own studies, we recommend design calculations in which (a) the probability of an estimate being in the wrong direction (Type S [sign] error) and (b) the factor by which the magnitude of an effect might be overestimated (Type M [magnitude] error or exaggeration ratio) are estimated. We illustrate with examples from recent published research and discuss the largest challenge in a design calculation: coming up with reasonable estimates of plausible effect sizes based on external information.

  19. The volcanic explosivity index /VEI/ - An estimate of explosive magnitude for historical volcanism

    NASA Technical Reports Server (NTRS)

    Newhall, C. G.; Self, S.

    1982-01-01

    A composite estimate of the magnitude of past explosive eruptions, referred to as the Volcanic Explosivity Index (VEI), is proposed as a semiquantitative compromise between poor data and the need in various disciplines to evaluate the record of past volcanism. The VEI is assigned to more than 8000 historic and prehistoric eruptions. It is shown that the VEI can help detect incompleteness and reporting biases and can help in selecting subsets of the historical record suitable for each study. The VEI is a composite estimate of Walkers (1980) magnitude and/or intensity and/or destructiveness and/or (less frequently) dispersive power, violence, and energy release rate, depending on the data that are available.

  20. A Deep Galex Color-Magnitude Diagram of the Galactic Globular Cluster M79

    NASA Astrophysics Data System (ADS)

    Schiavon, R.; O'Connell, R. W.; Rood, R. T.; Valenti, E.; Ferraro, F.; Green, E.; Liebert, J.; Peterson, R.

    2005-12-01

    Based on deep UV imaging of M 79 (NGC 1904), we have constructed the first GALEX color-magnitude diagram of a Galactic globular cluster. Our photometry reaches three magnitudes deeper in the far-UV than the deepest previous exposures, from the UIT telescope. As a result, we obtain a thorough characterization of the hot population in this well-known globular cluster. Here we present our first results for hot horizontal branch and blue straggler stars. In particular, with the large field of view provided by GALEX we were able to unveil the existence of a very large population of blue straggler candidates at very large distances from the cluster center. This result is discussed in light of the competing scenarios for the formation of blue stragglers in globular clusters. This work was supported in part by GALEX grant NNG05GE50G administered by JPL.

  1. Linking timing, magnitude and process-controls of floods in the United States

    NASA Astrophysics Data System (ADS)

    Berghuijs, Wouter; Woods, Ross; Hutton, Christopher; Sivapalan, Murugesu

    2016-04-01

    River flooding can have severe societal, economic and environmental consequences. However, limited understanding of the regional differences in flood generating mechanisms results in poorly understood flood trends, and consequently, uncertain predictions of future flood conditions. Through systematic data analyses of 420 catchments we expose the primary drivers of flooding across the contiguous United States. This is achieved by exploring which flood-generating processes control the seasonality and magnitude of maximum annual flows. The regional patterns of seasonality and interannual variability of the magnitude of maximum annual flows are, in general, poorly explained by rainfall characteristics alone. For most catchments soil moisture dependent precipitation excess, snowmelt and rain-on-snow events are found to be much better predictors of flooding responses. The generated continental-scale classification of dominant flood generating processes emphasizes the disparity between extreme rainfall and flooding, and can assist predictions of the nature of flooding and flood risk within the continental US.

  2. RR Lyrae stars and color-magnitude diagram of the globular cluster NGC 6388

    NASA Technical Reports Server (NTRS)

    Silbermann, N. A.; Smith, Horace A.; Bolte, Michael; Hazen, Martha L.

    1994-01-01

    We present new V, B-V, and V, V-R color-magnitude diagrams for the bulge globular cluster NGC 6388. These diagrams indicate that NGC 6388 is a metal-rich globular cluster with color-magnitude morphology similar to that of 47 Tucanae. We have conducted a search for new variable stars close to NGC 6388, finding three new RR Lyrae stars. The membership of these and previously discovered RR Lyrae stars near NGC 6388 is discussed. There is reason for believing that some of these variables are nonmembers. Others, however, may belong to the cluster and may be similar to the RR Lyrae star V9 in 47 Tuc.

  3. Debris flows in Grand Canyon National Park, Arizona: magnitude, frequency and effects on the Colorado River

    USGS Publications Warehouse

    Melis, Theodre S.; Webb, Robert H.; ,

    1993-01-01

    Debris flows are recurrent sediment-transport processes in 525 tributaries of the Colorado River in Grand Canyon. Arizona. Initiated by slope failures in bedrock and (or) colluvium during intense rainfall, Grand Canyon debris flows are high-magnitude, short-duration floods. Debris flows in these tributaries transport very large boulders into the river where they accumulate on debris fans and form rapids. The frequency of debris flows range from less than 1 per century to 10 or more per century in these tributaries. Before regulation by Glen Canyon Dam in 1963, high-magnitude floods on the Colorado River reworked debris fans by eroding all particles except large boulders. Because flow regulation has substantially decreased the river's competence, debris flows occurring after 1963 have increased accumulation of finer-grained sediments on debris fans and in rapids.

  4. Effects of urbanization on the magnitude and frequency of floods in northeastern Illinois

    USGS Publications Warehouse

    Allen, Howard E.; Bejcek, Richard M.

    1979-01-01

    Changes in land use associated with urbanization have increased flood-peak discharges in northeastern Illinois by factors up to 3.2. Techniques are presented for estimating the magnitude and frequency of floods in the urban environment of northeastern Illinois, and for estimating probable changes in flood characteristics that may be expected to accompany progressive urbanization. Suggestions also are offered for estimating the effects of urbanization on flood characteristics in areas other than northeastern Illinois. Three variables, drainage area, channel slope, and percent imperviousness (an urbanization factor), are used to estimate flood magnitudes for frequencies ranging from 2 to 500 years. Multiple regression analyses were used to relate flood-discharge data to the above watershed characteristics for 103 gaged watersheds. These watersheds ranged in drainage area from 0.07 to 630 square miles, in channel slope from 1.1 to 115 feet per mile, and in imperviousness from 1 to 39 percent. (Woodard-USGS)

  5. Spectrophotometry of Wolf-Rayet stars - Intrinsic colors and absolute magnitudes

    NASA Technical Reports Server (NTRS)

    Torres-Dodgen, Ana V.; Massey, Philip

    1988-01-01

    Absolute spectrophotometry of about 10-A resolution in the range 3400-7300 A have been obtained for southern Wolf-Rayet stars, and line-free magnitudes and colors have been constructed. The emission-line contamination in the narrow-band ubvr systems of Westerlund (1966) and Smith (1968) is shown to be small for most WN stars, but to be quite significant for WC stars. It is suggested that the more severe differences in intrinsic color from star to star of the same spectral subtype noted at shorter wavelengths are due to differences in atmospheric extent. True continuum absolute visual magnitudes and intrinsic colors are obtained for the LMC WR stars. The most visually luminous WN6-WN7 stars are found to be located in the core of the 30 Doradus region.

  6. Neurons within the same network independently achieve conserved output by differentially balancing variable conductance magnitudes.

    PubMed

    Ransdell, Joseph L; Nair, Satish S; Schulz, David J

    2013-06-12

    Biological and theoretical evidence suggest that individual neurons may achieve similar outputs by differentially balancing variable underlying ionic conductances. Despite the substantial amount of data consistent with this idea, a direct biological demonstration that cells with conserved output, particularly within the same network, achieve these outputs via different solutions has been difficult to achieve. Here we demonstrate definitively that neurons from native neural networks with highly similar output achieve this conserved output by differentially tuning underlying conductance magnitudes. Multiple motor neurons of the crab (Cancer borealis) cardiac ganglion have highly conserved output within a preparation, despite showing a 2-4-fold range of conductance magnitudes. By blocking subsets of these currents, we demonstrate that the remaining conductances become unbalanced, causing disparate output as a result. Therefore, as strategies to understand neuronal excitability become increasingly sophisticated, it is important that such variability in excitability of neurons, even among those within the same individual, is taken into account. PMID:23761890

  7. Magnitude-estimation scaling of complex auditory stimuli: native and nonnative languages.

    PubMed

    Fucci, D; McColl, D; Bond, Z; Stockmal, V

    1997-12-01

    50 subjects used magnitude-estimation scaling to rate 11 languages on two subjective perceptual tasks. On Task 1, the subjects rated languages according to how similar they were to their native language (English). In Task 2, the subjects rated languages according to how much they like them. Analysis showed a high over-all correlation between how similar subjects felt the languages were to their native language and how much they liked them (Pearson product-correlation r = .86). The high correlation indicates consistency in subjects' scaling responses. This consistency may suggest that magnitude estimation is an appropriate method for scaling complex auditory stimuli represented by various attributes of native and nonnative languages.

  8. The visual magnitudes of stars in the Almagest of Ptolemeus and in later catalogues.

    NASA Astrophysics Data System (ADS)

    Schmidt, H.

    1994-09-01

    The visual magnitudes of the Almagest have been compared with modern photoelectric measurements in V. Later catalogues equally based on visual estimates have been included. The various catalogues correlate rather well. Systematic effects due to extinction and the colour of the stars have been investigated. In spite of the hopes of the early observers no stars with very slow but systematic brightness variations have been found.

  9. Optimum quantisers for a Gaussian input probability density and for the magnitude-error distortion measure

    NASA Technical Reports Server (NTRS)

    Demaret, J. C.

    1975-01-01

    The parameters of non-uniform and uniform quantizers up to ten bits of quantization, optimum for a Gaussian input probability and for the magnitude-error distortion criterion are computed. Optimum quantizers must be understood as quantizers with minimum distortion. The numerical method used for the optimization converges relatively rapidly. The comparison between optimum non-uniform quantizers and optimum uniform quantizers is made.

  10. Determining Sliding Velocity and Shear-Strain Magnitude From Basal Sediments of Past Ice Sheets

    NASA Astrophysics Data System (ADS)

    Iverson, N. R.; Hooyer, T. S.; Thomason, J. F.

    2004-12-01

    Ice sheets slide over their basal sediments and commonly deform them. Despite meticulous description of such sediments, they have not been used to estimate rates or magnitudes of basal motion. Thus, although a common assertion is that modeling of past ice sheets can benefit from studies of basal sediments, their actual utility in modeling studies has been minimal. We have developed methods for estimating sliding velocity and till shear-strain magnitude from basal sediments of past ice sheets. The first method involves balancing shear traction on clasts that have plowed through the bed surface with resistance to plowing provided by the bed. The shear traction on clasts is provided by the sliding theory of Lliboutry, and plowing resistance is estimated using a geotechnical theory of cone penetration. The result is an expression for sliding speed of a past ice sheet that depends only on the size distribution of clasts that plowed and the thermomechanical properties of ice and clasts. This method was applied to sizes of clasts that plowed through outwash near Peoria, Illinois, to estimate the sliding speed of the Illinoian ice sheet in that area: 60-170 m/a. The second method involves shearing till in laboratory experiments to study the evolution of till microstructural properties as a function of shear-strain magnitude. Microstructural anisotropy is quantified by collecting multiple intact samples (20 mm cubes) and determining the strength of fabric defined by principal directions of magnetic susceptibility. These directions depend on alignment of needle-shaped magnetite grains. Fabrics formed by directions of maximum susceptibility do not become steady until shear strains of 20-50. Therefore, laboratory calibrations of fabric strength to shear-strain magnitude allow the extent of bed deformation to be determined from susceptibility fabrics of basal till. These studies can provide quantitative inputs to ice-sheet models that have been unavailable previously.

  11. 35-45 Giga Hertz Transceiver System for Phase and Magnitude Detection

    NASA Technical Reports Server (NTRS)

    Beni, Aman Aflaki

    2007-01-01

    Nondestructive evaluation (NDE) is the science and practice of examining an object in a way that the object's usefulness is not adversely affected. Different types of NDE methods exist but this thesis is based on microwave and millimeter wave NDE using imaging techniques. Microwave NDE is based on illuminating the object under test with a microwave signal and studying the various properties of the reflected signal from the object. This reflected signal contains some information about the inner structure of the object under test. This information may be contained in several parameters including the phase and magnitude of the reflected signal. The goal of this project is to design and build a Q-band coherent transceiver that is capable of measuring the reflected signal's phase and magnitude so that an image of the object under test may be reconstructed. From the several techniques that can be used to construct an image of the object under test, techniques of interest to this work include synthetic aperture focusing technique (SAFT) and microwave holography. The transceiver system should have the ability to sweep a large portion of Q-band frequency range in small frequency steps as quick as possible while the detected phase and magnitude of the reflected signal is very accurate. Several different designs were studied and the final schematic diagram of the transceiver system was determined. One of the most important modules that was designed, implemented and tested in the laboratory was an accurate phase/magnitude detector circuit. The compared results of the scans using the transceiver system and vector network analyzer (VNA) showed that this transceiver system has a great potential to replace a VNA for the purpose of microwave and millimeter wave imaging.

  12. Predicting the Maximum Earthquake Magnitude from Seismic Data in Israel and Its Neighboring Countries

    PubMed Central

    2016-01-01

    This paper explores several data mining and time series analysis methods for predicting the magnitude of the largest seismic event in the next year based on the previously recorded seismic events in the same region. The methods are evaluated on a catalog of 9,042 earthquake events, which took place between 01/01/1983 and 31/12/2010 in the area of Israel and its neighboring countries. The data was obtained from the Geophysical Institute of Israel. Each earthquake record in the catalog is associated with one of 33 seismic regions. The data was cleaned by removing foreshocks and aftershocks. In our study, we have focused on ten most active regions, which account for more than 80% of the total number of earthquakes in the area. The goal is to predict whether the maximum earthquake magnitude in the following year will exceed the median of maximum yearly magnitudes in the same region. Since the analyzed catalog includes only 28 years of complete data, the last five annual records of each region (referring to the years 2006–2010) are kept for testing while using the previous annual records for training. The predictive features are based on the Gutenberg-Richter Ratio as well as on some new seismic indicators based on the moving averages of the number of earthquakes in each area. The new predictive features prove to be much more useful than the indicators traditionally used in the earthquake prediction literature. The most accurate result (AUC = 0.698) is reached by the Multi-Objective Info-Fuzzy Network (M-IFN) algorithm, which takes into account the association between two target variables: the number of earthquakes and the maximum earthquake magnitude during the same year. PMID:26812351

  13. Instrumental magnitude constraints for the 1889 Chilik and the 1887 Verny earthquake, Central Asia

    NASA Astrophysics Data System (ADS)

    Krueger, Frank; Kulikova, Galina; Landgraf, Angela

    2016-04-01

    A series of four large earthquakes hit the continental collision region north of Lake Issyk Kul in the years 1885, 1887, 1889 and 1911 with magnitudes above 6.9. The largest event was the Chilik earthquake on July 11, 1889 with M 8.3 based on macroseismic intensities, recently confirmed by Bindi et al. (2013). Despite the existence of several juvenile fault scarps in the epicentral region no on scale through-going surface rupture has been located. Rupture length of ~200 km and slip of ~10 m are expected for M 8.3 (Blaser et al., 2010). The lack of high concentrated epicentral intensities require a hypocenter depth of 40 km located in the lower crust. Late coda envelope amplitude comparison of modern events in Central Asia recorded at stations in Northern Germany with the reproduction of a Rebeur-Paschwitz pendulum seismogram recorded at Wilhelmshaven results in a magnitude estimate of Mw 8.0-8.5. Amplitude comparison of longperiod surface waves measured on magnetograms at two british geomagnetic observatories favors a magnitude of Mw 8.0. Both can be made consistent if a station site factor of 2-4 for the Wilhelmshaven station is applied (for which indications exist). A truly deep centroid depth (h>40 km) is unlikely (from coda amplitude scaling), a shallow rupture of appropriate length is till now not discovered. Both arguments point to a possible lower crust contribution to the seismic moment. Magnetogram amplitudes for the Jun 8, 1887, Verny earthquake point to a magnitude of M ~7.5-7.6 (preliminary).

  14. Variable-period surface-wave magnitudes: A rapid and robust estimator of seismic moments

    USGS Publications Warehouse

    Bonner, J.; Herrmann, R.; Benz, H.

    2010-01-01

    We demonstrate that surface-wave magnitudes (Ms), measured at local, regional, and teleseismic distances, can be used as a rapid and robust estimator of seismic moment magnitude (Mw). We used the Russell (2006) variable-period surface-wave magnitude formula, henceforth called Ms(VMAX), to estimate the Ms for 165 North American events with 3.2 magnitude units (m.u). The residuals between Mw [Ms(VMAX)] and Mw [Waveform Modeling] show a significant focal mechanism effect, especially when strike-slip events are compared with other mechanisms. Validation testing of this method suggests that Ms(VMAX)-predicted Mw's can be estimated within minutes after the origin of an event and are typically within ??0.2 m.u. of the final Mw[Waveform Modeling]. While Mw estimated from Ms(VMAX) has a slightly higher variance than waveform modeling results, it can be measured on the first short-period surface-wave observed at a local or near-regional distance seismic station after a preliminary epicentral location has been formed. Therefore, it may be used to make rapid measurements of Mw, which are needed by government agencies for early warning systems.

  15. Effects of Phonation Time and Magnitude Dose on Vocal Fold Epithelial Genes, Barrier Integrity, and Function

    PubMed Central

    Kojima, Tsuyoshi; Valenzuela, Carla V.; Novaleski, Carolyn K.; Van Deusen, Mark; Mitchell, Joshua R.; Garrett, C. Gaelyn; Sivasankar, M. Preeti; Rousseau, Bernard

    2014-01-01

    Objective To investigate the effects of increasing time and magnitude doses of vibration exposure on transcription of the vocal fold's junctional proteins, structural alterations, and functional tissue outcomes. Study Design Animal study. Methods 100 New Zealand White breeder rabbits were studied. Dependent variables were measured in response to increasing time doses (30, 60, or 120 minutes) and magnitude doses (control, modal intensity, and raised intensity) of vibration exposure. Messenger RNA expression of occludin, zonula occluden-1 (ZO-1), E-cadherin, β-catenin, interleukin 1β (IL-1β), cyclooxygenase-2 (COX-2), transforming growth factor β-1 (TGFβ1), and fibronectin were measured. Tissue structural alterations were assessed using transmission electron microscopy (TEM). Transepithelial resistance was used to measure functional tissue outcomes. Results Occludin gene expression was downregulated in vocal folds exposed to 120 minute time doses of raised intensity phonation, relative to control, and modal intensity phonation. ZO-1 gene expression was upregulated following a 120 minute time dose of modal intensity phonation, compared to control, and downregulated after a 120 minute time dose of raised intensity phonation, compared to modal intensity phonation. E-cadherin gene expression was downregulated after a120 minute time dose of raised intensity phonation, compared to control and modal intensity phonation. TEM revealed extensive desquamation of the stratified squamous epithelial cells with increasing time and magnitude doses of vibration exposure. A general observation of lower transepithelial resistance measures was made in tissues exposed to raised intensity phonation, compared to all other groups. Conclusions This study provides evidence of vocal fold tissue responses to varying time and magnitude doses of vibration exposure. Level of Evidence N/A PMID:25073715

  16. Origin of how steam rockets can reduce space transport cost by orders of magnitude

    SciTech Connect

    Zuppero, A.; Larson, T.K.; Schnitzler, B.G.; Rice, J.W.; Hill, T.J.; Richins, W.D.; Parlier, L.; Werner, J.E.

    1999-01-01

    A brief sketch shows the origin of why and how thermal rocket propulsion has the unique potential to dramatically reduce the cost of space transportation for most inner solar system missions of interest. Orders of magnitude reduction in cost are apparently possible when compared to all processes requiring electrolysis for the production of rocket fuels or propellants and to all electric propulsion systems. An order of magnitude advantage can be attributed to rocket propellant tank factors associated with storing water propellant, compared to cryogenic liquids. An order of magnitude can also be attributed to the simplicity of the extraction and processing of ice on the lunar surface, into an easily stored, non-cryogenic rocket propellant (water). A nuclear heated thermal rocket can deliver thousands of times its mass to Low Earth Orbit from the Lunar surface, providing the equivalent to orders of magnitude drop in launch cost for mass in Earth orbit. Mass includes water ice. These cost reductions depend (exponentially) on the mission delta-v requirements being less than about 6 km/s, or about 3 times the specific velocity of steam rockets (2 km/s, from Isp 200 sec). Such missions include: from the lunar surface to Low Lunar Orbit, (LLO), from LLO to lunar escape, from Low Earth Orbit (LEO) to Geosynchronous Orbit (GEO), from LEO to Earth Escape, from LEO to Mars Transfer Orbit, from LLO to GEO, missions returning payloads from about 10{percent} of the periodic comets using propulsive capture to orbits around Earth itself, and fast, 100 day missions from Lunar Escape to Mars. All the assertions depend entirely and completely on the existence of abundant, nearly pure ice at the permanently dark North and South Poles of the Moon. {copyright} {ital 1999 American Institute of Physics.}

  17. Numerical magnitude processing in abacus-trained children with superior mathematical ability: an EEG study.

    PubMed

    Huang, Jian; Du, Feng-lei; Yao, Yuan; Wan, Qun; Wang, Xiao-Song; Chen, Fei-Yan

    2015-08-01

    Distance effect has been regarded as the best established marker of basic numerical magnitude processes and is related to individual mathematical abilities. A larger behavioral distance effect is suggested to be concomitant with lower mathematical achievement in children. However, the relationship between distance effect and superior mathematical abilities is unclear. One could get superior mathematical abilities by acquiring the skill of abacus-based mental calculation (AMC), which can be used to solve calculation problems with exceptional speed and high accuracy. In the current study, we explore the relationship between distance effect and superior mathematical abilities by examining whether and how the AMC training modifies numerical magnitude processing. Thus, mathematical competencies were tested in 18 abacus-trained children (who accepted the AMC training) and 18 non-trained children. Electroencephalography (EEG) waveforms were recorded when these children executed numerical comparison tasks in both Arabic digit and dot array forms. We found that: (a) the abacus-trained group had superior mathematical abilities than their peers; (b) distance effects were found both in behavioral results and on EEG waveforms; (c) the distance effect size of the average amplitude on the late negative-going component was different between groups in the digit task, with a larger effect size for abacus-trained children; (d) both the behavioral and EEG distance effects were modulated by the notation. These results revealed that the neural substrates of magnitude processing were modified by AMC training, and suggested that the mechanism of the representation of numerical magnitude for children with superior mathematical abilities was different from their peers. In addition, the results provide evidence for a view of non-abstract numerical representation.

  18. Effects of non-symbolic numerical information suggest the existence of magnitude-space synesthesia.

    PubMed

    Gertner, Limor; Arend, Isabel; Henik, Avishai

    2012-08-01

    In number-space synesthesia, numbers are visualized in spatially defined arrays. In a recent study (Gertner et al. in Cortex, doi: 10.1016/j.cortex.2012.03.019 , 2012), we found that the size congruency effect (SiCE) for physical judgments (i.e., comparing numbers' physical sizes while ignoring their numerical values, for example, 8) was modulated by the spatial position of the presented numbers. Surprisingly, we found that the neutral condition, which is comprise solely of physical sizes (e.g., 3), was affected as well. This pattern gave rise to the idea that number-space synesthesia might entail not only discrete, ordered, meaningful symbols (i.e., Arabic numbers) but also continuous non-symbolic magnitudes (i.e., sizes, length, luminance, etc.). We tested this idea by assessing the performance of two number-space synesthetes and 12 matched controls in 3 comparative judgment tasks involving symbolic and non-symbolic stimuli: (1) Arabic numbers, (2) dot clusters, and (3) sizes of squares. The spatial position of the presented stimuli was manipulated to be compatible or incompatible with respect to the synesthetic number-space perceptions. Results revealed that for synesthetes, but not for controls, non-symbolic magnitudes (dot clusters) as well as symbolic magnitudes (i.e., Arabic numbers) interacted with space. Our study suggests that number-space synesthetes might have a general magnitude-space association that is not restricted to concrete symbolic stimuli. These findings support recent theories on the perception and evaluation of sizes in numerical cognition.

  19. Avalanche ecology and large magnitude avalanche events: Glacier National Park, Montana, USA

    USGS Publications Warehouse

    Fagre, Daniel B.; Peitzsch, Erich H.

    2010-01-01

    Large magnitude snow avalanches play an important role ecologically in terms of wildlife habitat, vegetation diversity, and sediment transport within a watershed. Ecological effects from these infrequent avalanches can last for decades. Understanding the frequency of such large magnitude avalanches is also critical to avalanche forecasting for the Going-to-the-Sun Road (GTSR). In January 2009, a large magnitude avalanche cycle occurred in and around Glacier National Park, Montana. The study site is the Little Granite avalanche path located along the GTSR. The study is designed to quantify change in vegetative cover immediately after a large magnitude event and document ecological response over a multi-year period. GPS field mapping was completed to determine the redefined perimeter of the avalanche path. Vegetation was inventoried using modified U.S. Forest Service Forest Inventory and Analysis plots, cross sections were taken from over 100 dead trees throughout the avalanche path, and an avalanche chronology was developed. Initial results indicate that the perimeter of this path was expanded by 30%. The avalanche travelled approximately 1200 vertical meters and 3 linear kilometers. Stands of large conifers as old as 150 years were decimated by the avalanche, causing a shift in dominant vegetation types in many parts of the avalanche path. Woody debris is a major ground cover up to 3 m in depth on lower portions of the avalanche path and will likely affect tree regrowth. Monitoring and measuring the post-avalanche vegetation recovery of this particular avalanche path provides a unique dataset for determining the ecological role of avalanches in mountain landscapes.

  20. Increased rates of large‐magnitude explosive eruptions in Japan in the late Neogene and Quaternary

    PubMed Central

    Sparks, R. S. J.; Wallace, L. M.; Engwell, S. L.; Scourse, E. M.; Barnard, N. H.; Kandlbauer, J.; Brown, S. K.

    2016-01-01

    Abstract Tephra layers in marine sediment cores from scientific ocean drilling largely record high‐magnitude silicic explosive eruptions in the Japan arc for up to the last 20 million years. Analysis of the thickness variation with distance of 180 tephra layers from a global data set suggests that the majority of the visible tephra layers used in this study are the products of caldera‐forming eruptions with magnitude (M) > 6, considering their distances at the respective drilling sites to their likely volcanic sources. Frequency of visible tephra layers in cores indicates a marked increase in rates of large magnitude explosive eruptions at ∼8 Ma, 6–4 Ma, and further increase after ∼2 Ma. These changes are attributed to major changes in tectonic plate interactions. Lower rates of large magnitude explosive volcanism in the Miocene are related to a strike‐slip‐dominated boundary (and temporary cessation or deceleration of subduction) between the Philippine Sea Plate and southwest Japan, combined with the possibility that much of the arc in northern Japan was submerged beneath sea level partly due to previous tectonic extension of northern Honshu related to formation of the Sea of Japan. Changes in plate motions and subduction dynamics during the ∼8 Ma to present period led to (1) increased arc‐normal subduction in southwest Japan (and resumption of arc volcanism) and (2) shift from extension to compression of the upper plate in northeast Japan, leading to uplift, crustal thickening and favorable conditions for accumulation of the large volumes of silicic magma needed for explosive caldera‐forming eruptions.

  1. Predicting the Maximum Earthquake Magnitude from Seismic Data in Israel and Its Neighboring Countries.

    PubMed

    Last, Mark; Rabinowitz, Nitzan; Leonard, Gideon

    2016-01-01

    This paper explores several data mining and time series analysis methods for predicting the magnitude of the largest seismic event in the next year based on the previously recorded seismic events in the same region. The methods are evaluated on a catalog of 9,042 earthquake events, which took place between 01/01/1983 and 31/12/2010 in the area of Israel and its neighboring countries. The data was obtained from the Geophysical Institute of Israel. Each earthquake record in the catalog is associated with one of 33 seismic regions. The data was cleaned by removing foreshocks and aftershocks. In our study, we have focused on ten most active regions, which account for more than 80% of the total number of earthquakes in the area. The goal is to predict whether the maximum earthquake magnitude in the following year will exceed the median of maximum yearly magnitudes in the same region. Since the analyzed catalog includes only 28 years of complete data, the last five annual records of each region (referring to the years 2006-2010) are kept for testing while using the previous annual records for training. The predictive features are based on the Gutenberg-Richter Ratio as well as on some new seismic indicators based on the moving averages of the number of earthquakes in each area. The new predictive features prove to be much more useful than the indicators traditionally used in the earthquake prediction literature. The most accurate result (AUC = 0.698) is reached by the Multi-Objective Info-Fuzzy Network (M-IFN) algorithm, which takes into account the association between two target variables: the number of earthquakes and the maximum earthquake magnitude during the same year.

  2. Numerical magnitude processing in abacus-trained children with superior mathematical ability: an EEG study.

    PubMed

    Huang, Jian; Du, Feng-lei; Yao, Yuan; Wan, Qun; Wang, Xiao-Song; Chen, Fei-Yan

    2015-08-01

    Distance effect has been regarded as the best established marker of basic numerical magnitude processes and is related to individual mathematical abilities. A larger behavioral distance effect is suggested to be concomitant with lower mathematical achievement in children. However, the relationship between distance effect and superior mathematical abilities is unclear. One could get superior mathematical abilities by acquiring the skill of abacus-based mental calculation (AMC), which can be used to solve calculation problems with exceptional speed and high accuracy. In the current study, we explore the relationship between distance effect and superior mathematical abilities by examining whether and how the AMC training modifies numerical magnitude processing. Thus, mathematical competencies were tested in 18 abacus-trained children (who accepted the AMC training) and 18 non-trained children. Electroencephalography (EEG) waveforms were recorded when these children executed numerical comparison tasks in both Arabic digit and dot array forms. We found that: (a) the abacus-trained group had superior mathematical abilities than their peers; (b) distance effects were found both in behavioral results and on EEG waveforms; (c) the distance effect size of the average amplitude on the late negative-going component was different between groups in the digit task, with a larger effect size for abacus-trained children; (d) both the behavioral and EEG distance effects were modulated by the notation. These results revealed that the neural substrates of magnitude processing were modified by AMC training, and suggested that the mechanism of the representation of numerical magnitude for children with superior mathematical abilities was different from their peers. In addition, the results provide evidence for a view of non-abstract numerical representation. PMID:26238541

  3. Estimating the magnitude of peak flows at selected recurrence intervals for streams in Idaho

    USGS Publications Warehouse

    Berenbrock, Charles

    2002-01-01

    The region-of-influence method is not recommended for use in determining flood-frequency estimates for ungaged sites in Idaho because the results, overall, are less accurate and the calculations are more complex than those of regional regression equations. The regional regression equations were considered to be the primary method of estimating the magnitude and frequency of peak flows for ungaged sites in Idaho.

  4. Increased rates of large-magnitude explosive eruptions in Japan in the late Neogene and Quaternary

    NASA Astrophysics Data System (ADS)

    Mahony, S. H.; Sparks, R. S. J.; Wallace, L. M.; Engwell, S. L.; Scourse, E. M.; Barnard, N. H.; Kandlbauer, J.; Brown, S. K.

    2016-07-01

    Tephra layers in marine sediment cores from scientific ocean drilling largely record high-magnitude silicic explosive eruptions in the Japan arc for up to the last 20 million years. Analysis of the thickness variation with distance of 180 tephra layers from a global data set suggests that the majority of the visible tephra layers used in this study are the products of caldera-forming eruptions with magnitude (M) > 6, considering their distances at the respective drilling sites to their likely volcanic sources. Frequency of visible tephra layers in cores indicates a marked increase in rates of large magnitude explosive eruptions at ˜8 Ma, 6-4 Ma, and further increase after ˜2 Ma. These changes are attributed to major changes in tectonic plate interactions. Lower rates of large magnitude explosive volcanism in the Miocene are related to a strike-slip-dominated boundary (and temporary cessation or deceleration of subduction) between the Philippine Sea Plate and southwest Japan, combined with the possibility that much of the arc in northern Japan was submerged beneath sea level partly due to previous tectonic extension of northern Honshu related to formation of the Sea of Japan. Changes in plate motions and subduction dynamics during the ˜8 Ma to present period led to (1) increased arc-normal subduction in southwest Japan (and resumption of arc volcanism) and (2) shift from extension to compression of the upper plate in northeast Japan, leading to uplift, crustal thickening and favorable conditions for accumulation of the large volumes of silicic magma needed for explosive caldera-forming eruptions.

  5. Methane emissions from global rice fields: Magnitude, spatiotemporal patterns, and environmental controls

    NASA Astrophysics Data System (ADS)

    Zhang, Bowen; Tian, Hanqin; Ren, Wei; Tao, Bo; Lu, Chaoqun; Yang, Jia; Banger, Kamaljit; Pan, Shufen

    2016-09-01

    Given the importance of the potential positive feedback between methane (CH4) emissions and climate change, it is critical to accurately estimate the magnitude and spatiotemporal patterns of CH4 emissions from global rice fields and better understand the underlying determinants governing the emissions. Here we used a coupled biogeochemical model in combination with satellite-derived contemporary inundation area to quantify the magnitude and spatiotemporal variation of CH4 emissions from global rice fields and attribute the environmental controls of CH4 emissions during 1901-2010. Our study estimated that CH4 emissions from global rice fields varied from 18.3 ± 0.1 Tg CH4/yr (Avg. ±1 SD) under intermittent irrigation to 38.8 ± 1.0 Tg CH4/yr under continuous flooding in the 2000s, indicating that the magnitude of CH4 emissions from global rice fields is largely dependent on different water schemes. Over the past 110 years, our simulated results showed that global CH4 emissions from rice cultivation increased by 85%. The expansion of rice fields was the dominant factor for the increasing trends of CH4 emissions, followed by elevated CO2 concentration, and nitrogen fertilizer use. On the contrary, climate variability had reduced the cumulative CH4 emissions for most of the years over the study period. Our results imply that CH4 emissions from global rice fields could be reduced through optimizing irrigation practices. Therefore, the future magnitude of CH4 emissions from rice fields will be determined by the human demand for rice production as well as the implementation of optimized water management practices.

  6. Reflection magnitude as a predictor of mortality: the Multi-Ethnic Study of Atherosclerosis.

    PubMed

    Zamani, Payman; Jacobs, David R; Segers, Patrick; Duprez, Daniel A; Brumback, Lyndia; Kronmal, Richard A; Lilly, Scott M; Townsend, Raymond R; Budoff, Matthew; Lima, Joao A; Hannan, Peter; Chirinos, Julio A

    2014-11-01

    Arterial wave reflections have been associated with mortality in an ethnically homogenous Asian population. It is unknown whether this association is present in a multiethnic population or whether it is independent of subclinical atherosclerosis. We hypothesized that reflection magnitude (defined as the ratio of the amplitude of the backward wave [Pb] to that of the forward wave [Pf]) is associated with all-cause mortality in a large multiethnic adult community-based sample. We studied 5984 participants enrolled in the Multi-Ethnic Study of Atherosclerosis who had analyzable arterial tonometry waveforms. During 9.8±1.7 years of follow-up, 617 deaths occurred, of which 134 (22%) were adjudicated cardiovascular deaths. In Cox proportional hazards models, each 10% increase in reflection magnitude was associated with a 31% increased risk for all-cause mortality (hazard ratio [HR]=1.31; 95% confidence interval [CI]=1.11-1.55; P=0.001). This relationship persisted after adjustment for various confounders and for markers of subclinical atherosclerosis (HR=1.23; 95% CI=1.01-1.51; P=0.04), including the coronary calcium score, ankle-brachial index, common carotid intima-media thickness, and ascending thoracic aortic Agatston score. Pb was independently associated with all-cause mortality in a similarly adjusted model (HR per 10 mm Hg increase in P(b)=2.18; 95% CI=1.21-3.92; P=0.009). Reflection magnitude (HR=1.71; 95% CI=1.06-2.77; P=0.03) and P(b) (HR=5.02; 95% CI=1.29-19.42; P=0.02) were mainly associated with cardiovascular mortality. In conclusion, reflection magnitude is independently associated with all-cause mortality in a multiethnic population initially free of clinically evident cardiovascular disease. This relationship persists after adjustment for a comprehensive set of markers of subclinical atherosclerosis.

  7. Increased rates of large‐magnitude explosive eruptions in Japan in the late Neogene and Quaternary

    PubMed Central

    Sparks, R. S. J.; Wallace, L. M.; Engwell, S. L.; Scourse, E. M.; Barnard, N. H.; Kandlbauer, J.; Brown, S. K.

    2016-01-01

    Abstract Tephra layers in marine sediment cores from scientific ocean drilling largely record high‐magnitude silicic explosive eruptions in the Japan arc for up to the last 20 million years. Analysis of the thickness variation with distance of 180 tephra layers from a global data set suggests that the majority of the visible tephra layers used in this study are the products of caldera‐forming eruptions with magnitude (M) > 6, considering their distances at the respective drilling sites to their likely volcanic sources. Frequency of visible tephra layers in cores indicates a marked increase in rates of large magnitude explosive eruptions at ∼8 Ma, 6–4 Ma, and further increase after ∼2 Ma. These changes are attributed to major changes in tectonic plate interactions. Lower rates of large magnitude explosive volcanism in the Miocene are related to a strike‐slip‐dominated boundary (and temporary cessation or deceleration of subduction) between the Philippine Sea Plate and southwest Japan, combined with the possibility that much of the arc in northern Japan was submerged beneath sea level partly due to previous tectonic extension of northern Honshu related to formation of the Sea of Japan. Changes in plate motions and subduction dynamics during the ∼8 Ma to present period led to (1) increased arc‐normal subduction in southwest Japan (and resumption of arc volcanism) and (2) shift from extension to compression of the upper plate in northeast Japan, leading to uplift, crustal thickening and favorable conditions for accumulation of the large volumes of silicic magma needed for explosive caldera‐forming eruptions. PMID:27656115

  8. An automated technique for stellar magnitude, color index, and position measurements of astronomical photographs

    NASA Technical Reports Server (NTRS)

    Green, R. F.; Morrill, M. E.

    1978-01-01

    Computer programs have been developed for use in collecting and processing data from a PDS scanning microdensitometer. The goal is to obtain fast and simple algorithms for handling an entire astronomical photograph with one-pass digitization. This capability is realized by a real-time detection scheme that provides a data compression of a factor of 100, and a processing program that produces a catalog of magnitudes, color indices, and positions for up to 90,000 multicolor stellar images.

  9. Arm Swing Magnitude and Asymmetry During Gait in the Early Stages of Parkinson's Disease

    PubMed Central

    Lewek, Michael D.; Poole, Roxanne; Johnson, Julia; Halawa, Omar; Huang, Xuemei

    2009-01-01

    The later stages of Parkinson's disease (PD) are characterized by altered gait patterns. Although decreased arm swing during gait is the most frequently reported motor dysfunction in individuals with PD, quantitative descriptions of gait in early PD have largely ignored upper extremity movements. This study was designed to perform a quantitative analysis of arm swing magnitude and asymmetry that might be useful in the assessment of early PD. Twelve individuals with early PD (in “off” state) and eight controls underwent gait analysis using an optically-based motion capture system. Participants were instructed to walk at normal and fast velocities, and then on heels (to minimize push-off). Arm swing was measured as the excursion of the wrist with respect to the pelvis. Arm swing magnitude for each arm, and inter-arm asymmetry, were compared between groups. Both groups had comparable gait velocities (p=0.61), and there was no significant difference between the groups in the magnitude of arm swing in all walking conditions for the arm that swung more (p=0.907) or less (p=0.080). Strikingly, the PD group showed significantly greater arm swing asymmetry (asymmetry angle: 13.9±7.9%) compared to the control group (asymmetry angle: 5.1±4.0%; p=0.003). Unlike arm swing magnitude, arm swing asymmetry unequivocally differs between people with early PD and controls. Such quantitative evaluation of arm swing, especially its asymmetry, may have utility for early and differential diagnosis, and for tracking disease progression in patients with later PD. PMID:19945285

  10. Nevado del Huila, Columbia

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Nevado del Huila Volcano in Colombia is actually a volcanic chain running north to south, capped by a glacier. With peaks ranging in height from 2,600 to 5,780 meters (8,530 to 18,960 feet), Nevado del Huila is a stratovolcano composed of alternating layers of hardened lava, solidified ash, and volcanic rocks. Its first recorded eruption occurred in the mid-sixteenth century. The long-dormant volcano erupted again in mid-April 2007. A few months before the eruption, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite captured this image of Nevado del Huila, on February 23, 2007. In this image, the bright white area just east of the central summit is ice. Immediately west of the summit are bare rocks, appearing as blue-gray. West of those rocks, white reappears, but this patch of white results from clouds hovering in the nearby valley. In the east, the colors turn to brown (indicating bare rock) and bright green (indicating vegetation). ASTER photographed Nevado del Huila near the end of a long phase of quietude. On April 17, 2007, local authorities recorded seismic activity associated with rock fracturing on the volcano's central summit, according to the ReliefWeb Website. Activity intensified the following day with an eruption and mudflows, forcing thousands of nearby residents to evacuate. As the Associated Press reported, the eruption caused avalanches and floods that wiped away both houses and bridges. It marked the volcano's first recorded eruption since the Spanish colonized the area five centuries earlier. NASA image created by Jesse Allen, using data provided courtesy of the NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team.

  11. The effect of compressive loading magnitude on in situ chondrocyte calcium signaling.

    PubMed

    Madden, Ryan M J; Han, Sang-Kuy; Herzog, Walter

    2015-01-01

    Chondrocyte metabolism is stimulated by deformation and is associated with structural changes in the cartilage extracellular matrix (ECM), suggesting that these cells are involved in maintaining tissue health and integrity. Calcium signaling is an initial step in chondrocyte mechanotransduction that has been linked to many cellular processes. Previous studies using isolated chondrocytes proposed loading magnitude as an important factor regulating this response. However, calcium signaling in the intact cartilage differs compared to isolated cells. The purpose of this study was to investigate the effect of loading magnitude on chondrocyte calcium signaling in intact cartilage. We hypothesized that the percentage of cells exhibiting at least one calcium signal increases with increasing load. Fully intact rabbit femoral condyle and patellar bone/cartilage samples were incubated in calcium-sensitive dyes and imaged continuously under compressive loads of 10-40 % strain. Calcium signaling was primarily associated with the dynamic loading phase and greatly increased beyond a threshold deformation of about 10 % nominal tissue strain. There was a trend toward more cells exhibiting calcium signaling as loading magnitude increased (p = 0.133). These results provide novel information toward identifying mechanisms underlying calcium-dependent signaling pathways related to cartilage homeostasis and possibly the onset and progression of osteoarthritis.

  12. pp ii Variation in reading error in P times for explosions with body-wave magnitude

    NASA Astrophysics Data System (ADS)

    Douglas, A.; Young, J. B.; Bowers, D.; Lewis, M.

    2005-09-01

    The differences between true travel-times of P and times predicted from travel-time tables (path effects) can be estimated for groups of closely spaced explosions with known hypocentres and origin times, if the onsets are observed at large signal-to-noise ratios (SNR) and read by analysts. Reading error can also be estimated and is usually assumed to be normally distributed with zero mean. Two experiments have been carried out to look at how reading error in P times from explosions varies with magnitude - taken as a measure of SNR - when read by analysts and by automatic systems. Although at low magnitudes there is some evidence of analyst readings being biased late, the largest variation in reading error with magnitude is found for automatic systems. The results show just how difficult it can be to estimate path effects free from observational bias, at least using bulletin data. The current programme to estimate path effects to improve epicentre location for verification of the Comprehensive Test Ban needs to include checks to ensure that apparent variations in path effects with location, are not due to bias from systematic reading error.

  13. Different Effects of Numerical Magnitude on Visual and Proprioceptive Reference Frames

    PubMed Central

    Blini, Elvio; Cattaneo, Zaira; Vallar, Giuseppe

    2013-01-01

    This study assessed whether numerical magnitude affects the setting of basic spatial coordinates and reference frames, namely the subjective straight ahead. Three tasks were given to 24 right-handed healthy participants: a proprioceptive and a visuo-proprioceptive task, requiring pointing to the subjective straight ahead, and a visual task, requiring a perceptual judgment about the straight ahead position of a light moving left-to-right, or right-to-left. A control task, requiring the bisection of rods of different lengths, was also given. The four tasks were performed under conditions of passive auditory numerical (i.e., listening to small, “2,” and large, “8,” numbers), and neutral auditory-verbal (“blah”) stimulation. Numerical magnitude modulated the participants’ deviations in the visual straight ahead task, when the movement of the light was from left-to-right, with the small number bringing about a leftward deviation, the large number a rightward deviation. A similar directional modulation was found in the rod bisection task, in line with previous evidence. No effects of numerical magnitude were found on the proprioceptive and visuo-proprioceptive straight ahead tasks. These results suggest that the spatial effects induced by the activation of the mental number line extend to an egocentric frame of reference but only when a portion of horizontal space has to be “actively” explored. PMID:23616777

  14. THE LEO IV DWARF SPHEROIDAL GALAXY: COLOR-MAGNITUDE DIAGRAM AND PULSATING STARS

    SciTech Connect

    Moretti, Maria Ida; Dall'Ora, Massimo; Ripepi, Vincenzo E-mail: dallora@na.astro.it

    2009-07-10

    We present the first V, B - V color-magnitude diagram of the Leo IV dwarf spheroidal galaxy, a faint Milky Way satellite recently discovered by the Sloan Digital Sky Survey. We have obtained B, V time-series photometry reaching about half a magnitude below the Leo IV turnoff, which we detect at V = 24.7 mag, and have performed the first study of the variable star population. We have identified three RR Lyrae stars (all fundamental-mode pulsators, RRab) and one SX Phoenicis variable in the galaxy. In the period-amplitude diagram the Leo IV RR Lyrae stars are located close to the loci of Oosterhoff type I systems and the evolved fundamental-mode RR Lyrae stars in the Galactic globular cluster M3. However, their mean pulsation period, (Pab) = 0.655 days, would suggest an Oosterhoff type II classification for this galaxy. The RR Lyrae stars trace very well the galaxy's horizontal branch, setting its average magnitude at (V {sub RR}) = 21.48 {+-} 0.03 mag (standard deviation of the mean). This leads to a distance modulus of {mu}{sub 0} = 20.94 {+-} 0.07 mag, corresponding to a distance of 154 {+-} 5 kpc, by adopting for the Leo IV dSph a reddening E(B - V) = 0.04 {+-} 0.01 mag and a metallicity of [Fe/H] = -2.31 {+-} 0.10.

  15. Calibration for Coda Derived Moment Magnitude Using Berkeley Complete Waveform Moment-Tensor Solutions

    NASA Astrophysics Data System (ADS)

    Tajima, F.; Mayeda, K. M.; Dreger, D. S.; Wurman, G.

    2002-12-01

    The method of seismic moment-tensor determination using complete waveforms (Dreger and Helmberger, 1993; Pasyanos et al., 1996) provides stable solutions for local and regional events if the data propagation paths are well-calibrated to calculate Green's functions. However, this waveform modeling approach has a limitation to apply to smaller events with the cut-off magnitude of approximately 3.5 due to reduction of S/N ratios in the passband employed. We carried out an experiment to extend the moment magnitude scale to smaller events (M<3.5) in northern California using an empirical method of coda derived moment magnitude (Mw(coda)) calibration (Mayeda et al., 2002). The basic assumption of this approach is that the coda spectra are the results of scatters from randomly distributed inhomogeneities in the crust and represent seismic energy propagation, independent of the source radiation pattern, as a function of propagation distance with a specific attenuation rule. In practice we found that when the data propagation paths cross a wide range of different structural areas, the standard deviation of the parameters is large and the parameter estimation is less coherent. Thus, in the course of calibration the entire northern California is divided into several tectonic subregions, in each of which the calibration parameters are relatively coherent. The present study suggests a conservative application of the coda envelope calibration method to estimate Mw(coda) that avoids ambiguities.

  16. Impact of channel-like erosion patterns on the frequency-magnitude distribution of earthquakes

    NASA Astrophysics Data System (ADS)

    Rohmer, J.; Aochi, H.

    2015-07-01

    Reactive flow at depth (either related to underground activities, like enhancement of hydrocarbon recovery and CO2 storage, or to natural flow like in hydrothermal zones) can alter fractures' topography, which might in turn change their seismic responses. Depending on the flow and reaction rates, instability of the dissolution front can lead to a wormhole-like pronounced erosion pattern. In a fractal structure of rupture process, we question how the perturbation related to well-spaced long channels alters rupture propagation initiated on a weak plane and eventually the statistical feature of rupture appearance in frequency-magnitude distribution (FMD). Contrary to intuition, a spatially uniform dissolution is not the most remarkable case, since it affects all the events proportionally to their sizes leading to a downward translation of FMD: the slope of FMD (b-value) remains unchanged. The parameter-space study shows that the increase of b-value (of 0.08) is statistically significant for optimum characteristics of the erosion pattern with spacing to length ratio of the order of ˜1/40: large-magnitude events are more significantly affected leading to an imbalanced distribution in the magnitude bins of the FMD. The larger the spacing, the lower the channel's influence. Besides, a spatial analysis shows that the local seismicity anomaly concentrates in a limited zone around the channels: this opens perspective for detecting these eroded regions through high-resolution imaging surveys.

  17. Effects of gender and listeners' preference on magnitude-estimation scaling of rock music.

    PubMed

    Fucci, D; Petrosino, L; Banks, M

    1994-06-01

    The purpose of the present study was to examine the effects of gender and listener preference on magnitude-estimation scaling of rock music. Four groups of young adults were tested: 14 women who liked rock music, 14 women who disliked rock music, 14 men who liked rock music, and 14 men who disliked rock music. Subjects were instructed to assign numerical values to a random series of nine suprathreshold intensity levels of a 10-sec. sample of rock music. Analysis indicated that there was no difference in scaling performance between women and men. There was a difference in scaling performance between the group of women who liked rock music and the group of women who disliked rock music. There was no difference in the way the two groups of men performed the scaling task. These results suggest that men and women perform magnitude-estimation scaling of rock music similarly. Women, however, allow preference to influence how they choose numbers during magnitude-estimation scaling tasks whereas men do not.

  18. Star/galaxy separation at faint magnitudes: Application to a simulated Dark Energy Survey

    SciTech Connect

    Soumagnac, M.T.; et al.

    2013-06-21

    We address the problem of separating stars from galaxies in future large photometric surveys. We focus our analysis on simulations of the Dark Energy Survey (DES). In the first part of the paper, we derive the science requirements on star/galaxy separation, for measurement of the cosmological parameters with the Gravitational Weak Lensing and Large Scale Structure probes. These requirements are dictated by the need to control both the statistical and systematic errors on the cosmological parameters, and by Point Spread Function calibration. We formulate the requirements in terms of the completeness and purity provided by a given star/galaxy classifier. In order to achieve these requirements at faint magnitudes, we propose a new method for star/galaxy separation in the second part of the paper. We first use Principal Component Analysis to outline the correlations between the objects parameters and extract from it the most relevant information. We then use the reduced set of parameters as input to an Artificial Neural Network. This multi-parameter approach improves upon purely morphometric classifiers (such as the classifier implemented in SExtractor), especially at faint magnitudes: it increases the purity by up to 20% for stars and by up to 12% for galaxies, at i-magnitude fainter than 23.

  19. The effects of compensator design on scatter distribution and magnitude: a Monte Carlo study

    NASA Astrophysics Data System (ADS)

    Bootsma, G. J.; Verhaegen, F.; Jaffray, D. A.

    2011-03-01

    X-ray scatter has a significant impact on image quality in kV cone-beam CT (CBCT), its effects include: CT number inaccuracy, streak and cupping artifacts, and loss of contrast. Compensators provide a method for not only decreasing the magnitude of the scatter distribution, but also reducing the structure found in the scatter distribution. Recent Monte Carlo (MC) simulations examining X-ray scatter in CBCT projection images have shown that the scatter distribution in x-ray imaging contains structure largely induced by coherent scattering. In order to maximize the reduction of x-ray scatter induced artifacts a decrease in the magnitude and structure of the scatter distribution is sought through optimal compensator design. A flexible MC model that allows for separation of scattered and primary photons has been created to simulate the CBCT imaging process. The CBCT MC model is used to investigate the effectiveness of compensators in decreasing the magnitude and structure of the scatter distribution in CBCT projection images. The influence of the compensator designs on the scatter distribution are evaluated for different anatomy (abdomen, pelvis, and head and neck) and viewing angles using a voxelized anthropomorphic phantom. The effect of compensator material composition on the amount of contamination photons in an open field is also investigated.

  20. The visual surface brightness relation and the absolute magnitudes of RR Lyrae stars. I - Theory

    NASA Technical Reports Server (NTRS)

    Manduca, A.; Bell, R. A.

    1981-01-01

    A theoretical relation analogous to the Barnes-Evans relation between stellar surface brightness and V-R color is derived which is applicable to the temperatures and gravities appropriate to RR Lyrae stars. Values of the visual surface brightness and V-R colors are calculated for model stellar atmospheres with effective temperatures between 6000 and 8000 K, log surface gravities from 2.2 to 3.5, and A/H anbundance ratios from -0.5 to -3.0. The resulting relation is found to be in reasonable agreement with the empirical relation of Barnes, Evans and Moffet (1978), with, however, small sensitivities to gravity and metal abundance. The relation may be used to derive stellar angular diameters from (V,R) photometry and to derive radii, distances, and absolute magnitudes for variable stars when combined with a radial velocity curve. The accuracies of the radii and distances (within 10%) and absolute magnitudes (within 0.25 magnitudes) compare favorably with those of the Baade-Wesselink method currently in use.