Science.gov

Sample records for magnitud del problema

  1. Il problema del litio.

    NASA Astrophysics Data System (ADS)

    D'Antona, F.

    1995-03-01

    Contents: 1. Introduzione. 2. La nucleosintesi del Big Bang. 3. Il litio nelle stelle di popolazione II. 4. I modelli stellari standard. 5. Il litio negli ammassi aperti. 6. Meccanismi di distruzione "non standard". 7. I modelli non-standard applicati alla popolazione II. 8. L'evoluzione Galattica del litio. 9. Quali stelle producono litio? 10. Il litio come elemento chiave per dare un nome agli oggetti stellari più minuscoli. 11. Conclusioni.

  2. 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.

  3. Memorias del tercer simposio internacional sobre economía, planificación, y políticas de los incendios forestales: problemas y enfoques comunes

    Treesearch

    Armando González-Cabán

    2009-01-01

    Estas memorias resumen el resultado de un simposio diseñado para discutir los problemas actuales que confrontan las agencias con responsabilidad para la proteccion contra incendios forestales a nivel federal y estadual en los EE.UU., al igual que agencias en la comunidad internacional. Los temas discutidos en el simposio incluyen economía del fuego, teoría y modelos...

  4. Acerca de la linealidad de la relación color-magnitud del cúmulo de Virgo

    NASA Astrophysics Data System (ADS)

    González, N.; Smith Castelli, A.; Faifer, F.; Forte, J. C.

    In this work we revisite the color-magnitude relation (CMR) of the Virgo cluster by means of the realization of our own photometry and the analysis of images of 100 early-type galaxies, observed as part of the ACS Virgo Cluster Survey of the Hubble Space Telescope (HST). Our objective, within the framework of the discussion about the nonlinearity of the CMR in the Virgo cluster, is to draw a comparison between the results of the photometry performed in this work and the results obtained in previous ones. FULL TEXT IN SPANISH

  5. Propuesta Para La Creacion Del Cuerpo De Ingenieros De Las Fuerzas Armadas De Honduras. Proposal for the Creation of a Corps of Engineers in the Honduran Armed Forces

    DTIC Science & Technology

    2016-05-26

    15 Enunciado del problema ...16 Formulación del problema ... problema central que se presenta a menudo y que amerita su atención se centra en el desarrollo económico enfocados en la competitividad, desarrollo

  6. Automaticity of Conceptual Magnitude.

    PubMed

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

    2016-02-16

    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.

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. REINFORCER MAGNITUDE ATTENUATES

    PubMed Central

    Pinkston, Jonathan W.; Lamb, R. J.

    2012-01-01

    When given to pigeons, the direct-acting dopamine agonist apomorphine elicits pecking. The response has been likened to foraging pecking because it bears remarkable similarity to foraging behavior, and it is enhanced by food deprivation. On the other hand, other data suggest the response is not related to foraging behavior and may even interfere with food ingestion. Although elicited pecking interferes with food capture, it may selectively alter procurement phases of feeding, which can be isolated in operant preparations. To explore the relation between operant and elicited pecking, we provided pigeons the opportunity to earn different reinforcer magnitudes during experimental sessions. During signaled components, each of 4 pigeons could earn 2-, 4-, or 8-s access to grain for a single peck made at the end of a 5-min interval. In general, responding increased as a function of reinforcer magnitude. Apomorphine increased pecking for 2 pigeons and decreased pecking for the other 2. In both cases, apomorphine was more potent under the component providing the smallest reinforcer magnitude. Analysis of the pattern of pecking across the interval indicated that behavior lost its temporal organization as dose increased. Because apomorphine-induced pecking varied inversely with reinforcer magnitude, we conclude that elicited pecks are not functionally related to food procurement. The data are consistent with the literature on behavioral resistance to change and suggest that the effects of apomorphine may be modulated by prevailing stimulus–reinforcer relationships. PMID:23144505

  14. Magnitude estimation of softness

    PubMed Central

    Friedman, Robert M.; Hester, Kim D.; Green, Barry G.

    2008-01-01

    The human capacity to estimate the magnitude of softness of silicone rubber disks of differing compliance was studied under experimental conditions that altered the mode of contact. Subjects were able to scale softness regardless of whether they (1) actively indented each specimen by tapping or pressing it with the finger pad, (2) received passive indentation of the finger pad by each specimen via a force controlled tactile stimulator, thus eliminating kinesthetic cues, or (3) actively indented each specimen with a stylus that was manipulated either by tapping with one finger, or held by two fingers in a precision grip, thereby removing tactile cues provided by direct mechanical contact between the finger pad and specimen. Ratings of softness were independent of moderate variations in peak compressional force and force-rate. Additionally, functions for scaling softness were affected by the mode of contact; the slopes of the functions were greater in the tasks with a complete complement of compliance cues. When subjects were asked to classify objects as either hard or soft, specimens were classified as soft if the compliance were greater than that of the human finger. This suggests that the classification of softness depends on whether the object conforms to the body, and that tactile information about the spatial profile of object deformation is sufficient for the magnitude scaling of softness. But typically, kinesthetic information about the magnitude of object displacement, along with contact vibratory cues is also used while judging softness especially in the absence of direct skin contact with the object when using a tool. PMID:18679665

  15. 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.

  16. Limiting magnitude of hypertelescopes

    NASA Astrophysics Data System (ADS)

    Surya, Arun

    Optical stellar interferometers have demonstrated milli-arcsecond resolution with few apertures spaced hundreds of meters apart. To obtain rich direct images, many apertures will be needed, for a better sampling of the incoming wavefront. The coherent imaging thus achievable improves the sensitivity with respect to the incoherent combination of successive fringed exposures, heretofore achieved in the form of optical aperture synthesis. For efficient use of highly diluted apertures, this can be done with pupil densification, a technique also called ``Hypertelescope Imaging". Using numerical simulations we have found out the limiting magnitude of hypertelescopes over different baselines and pupil densifications. Here we discuss the advantages of using hypertelescope systems over classical pairwise optical interferometry.

  17. 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.

  18. Determination of the Limiting Magnitude

    NASA Technical Reports Server (NTRS)

    Kingery, Aaron; Blaauw, Rhiannon

    2017-01-01

    The limiting magnitude of an optical camera system is an important property to understand since it is used to find the completeness limit of observations. Limiting magnitude depends on the hardware and software of the system, current weather conditions, and the angular speed of the objects observed. If an object exhibits a substantial angular rate during the exposure, its light spreads out over more pixels than the stationary stars. This spreading causes the limiting magnitude to be brighter when compared to the stellar limiting magnitude. The effect, which begins to become important when the object moves a full width at half max during a single exposure or video frame. For targets with high angular speeds or camera systems with narrow field of view or long exposures, this correction can be significant, up to several magnitudes. The stars in an image are often used to measure the limiting magnitude since they are stationary, have known brightness, and are present in large numbers, making the determination of the limiting magnitude fairly simple. In order to transform stellar limiting magnitude to object limiting magnitude, a correction must be applied accounting for the angular velocity. This technique is adopted in meteor and other fast-moving object observations, as the lack of a statistically significant sample of targets makes it virtually impossible to determine the limiting magnitude before the weather conditions change. While the weather is the dominant factor in observing satellites, the limiting magnitude for meteors also changes throughout the night due to the motion of a meteor shower or sporadic source radiant across the sky. This paper presents methods for determining the limiting stellar magnitude and the conversion to the target limiting magnitude.

  19. 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.

  20. 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)

  1. 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)

  2. 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

  3. Puertorriquenos En Chicago: El Problema Educativo Del Dropout

    ERIC Educational Resources Information Center

    Lucas, Isidro

    1974-01-01

    Article written in Spanish. Defines the term "dropout," discusses the characteristics and motivations of Puerto Rican school dropouts in Chicago, and outlines the problems in educating them. (Author/RJ)

  4. Puertorriquenos En Chicago: El Problema Educativo Del Dropout

    ERIC Educational Resources Information Center

    Lucas, Isidro

    1974-01-01

    Article written in Spanish. Defines the term "dropout," discusses the characteristics and motivations of Puerto Rican school dropouts in Chicago, and outlines the problems in educating them. (Author/RJ)

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. Tectonic stress - Models and magnitudes

    NASA Technical Reports Server (NTRS)

    Solomon, S. C.; Bergman, E. A.; Richardson, R. M.

    1980-01-01

    It is shown that global data on directions of principal stresses in plate interiors can serve as a test of possible plate tectonic force models. Such tests performed to date favor force models in which ridge pushing forces play a significant role. For such models the general magnitude of regional deviatoric stresses is comparable to the 200-300 bar compressive stress exerted by spreading ridges. An alternative approach to estimating magnitudes of regional deviatoric stresses from stress orientations is to seek regions of local stress either demonstrably smaller than or larger than the regional stresses. The regional stresses in oceanic intraplate regions are larger than the 100-bar compression exerted by the Ninetyeast Ridge and less than the bending stresses (not less than 1 kbar) beneath Hawaii.

  10. Nontrivial Solutions to the Cubic Sieve Congruence Problem: x3 is congruent to y2z mod p: Soluciones no Triviales al problema de Congruencia de Criba Cubica: x3 is congruent to y2z mod p

    DTIC Science & Technology

    2009-01-01

    x3 6= y2z. Las soluciones a este problema resultan útiles para resolver el problema del logaritmo discreto o el de factorización entera cuando se...problema puede ser resuelto en tiempo polinomial en log p. Asimismo, extendimos la idea de cribado de Reyneri e identificamos algunas clases en donde el...problema puede ser resuelto en tiempo constante. Los diseñadores de cripto-esquemas deben evitar utilizar cualquiera de los primos contenidos en los

  11. Subject position affects EEG magnitudes.

    PubMed

    Rice, Justin K; Rorden, Christopher; Little, Jessica S; Parra, Lucas C

    2013-01-01

    EEG (electroencephalography) has been used for decades in thousands of research studies and is today a routine clinical tool despite the small magnitude of measured scalp potentials. It is widely accepted that the currents originating in the brain are strongly influenced by the high resistivity of skull bone, but it is less well known that the thin layer of CSF (cerebrospinal fluid) has perhaps an even more important effect on EEG scalp magnitude by spatially blurring the signals. Here it is shown that brain shift and the resulting small changes in CSF layer thickness, induced by changing the subject's position, have a significant effect on EEG signal magnitudes in several standard visual paradigms. For spatially incoherent high-frequency activity the effect produced by switching from prone to supine can be dramatic, increasing occipital signal power by several times for some subjects (on average 80%). MRI measurements showed that the occipital CSF layer between the brain and skull decreases by approximately 30% in thickness when a subject moves from prone to supine position. A multiple dipole model demonstrated that this can indeed lead to occipital EEG signal power increases in the same direction and order of magnitude as those observed here. These results suggest that future EEG studies should control for subjects' posture, and that some studies may consider placing their subjects into the most favorable position for the experiment. These findings also imply that special consideration should be given to EEG measurements from subjects with brain atrophy due to normal aging or neurodegenerative diseases, since the resulting increase in CSF layer thickness could profoundly decrease scalp potential measurements.

  12. The representation of numerical magnitude

    PubMed Central

    Brannon, Elizabeth M

    2006-01-01

    The combined efforts of many fields are advancing our understanding of how number is represented. Researchers studying numerical reasoning in adult humans, developing humans and non-human animals are using a suite of behavioral and neurobiological methods to uncover similarities and differences in how each population enumerates and compares quantities to identify the neural substrates of numerical cognition. An important picture emerging from this research is that adult humans share with non-human animals a system for representing number as language-independent mental magnitudes and that this system emerges early in development. PMID:16546373

  13. [Poverty in Mexico. II. Magnitude].

    PubMed

    Boltvinik, J

    1995-01-01

    This is the second part of a research report on the evolution and magnitude of poverty in Mexico. Application of the Integrated Poverty Measurement Method, explained in the first part of this report, shows a poverty headcount ratio (H) of 70.6% and an extreme poverty H of 44.7%. H turns out higher by the UBN (Unsatisfied Basic Needs) method than by the PLT (Poverty Line plus working time) approach. The poverty gap or poverty intensity (I), is for all poor 0.44 but reaches 0.58 for the extremely poor. Both H and I are substantially higher in the rural than in the urban areas. UBN poverty gap is bigger than the PLT gap. When UBN is disaggregated into its components, deprivation turns out the highest in health care and social security. Degree of poverty calculations (HI), the product of H and I, which constitute a good basis for anti-poverty expenditures allocation, show that despite the fact that a larger number of poor persons live in the urban areas, the number of equivalent poor people is higher in the rural areas.

  14. Rank distributions: Frequency vs. magnitude.

    PubMed

    Velarde, Carlos; Robledo, Alberto

    2017-01-01

    We examine the relationship between two different types of ranked data, frequencies and magnitudes. We consider data that can be sorted out either way, through numbers of occurrences or size of the measures, as it is the case, say, of moon craters, earthquakes, billionaires, etc. We indicate that these two types of distributions are functional inverses of each other, and specify this link, first in terms of the assumed parent probability distribution that generates the data samples, and then in terms of an analog (deterministic) nonlinear iterated map that reproduces them. For the particular case of hyperbolic decay with rank the distributions are identical, that is, the classical Zipf plot, a pure power law. But their difference is largest when one displays logarithmic decay and its counterpart shows the inverse exponential decay, as it is the case of Benford law, or viceversa. For all intermediate decay rates generic differences appear not only between the power-law exponents for the midway rank decline but also for small and large rank. We extend the theoretical framework to include thermodynamic and statistical-mechanical concepts, such as entropies and configuration.

  15. Astronomical Limiting Magnitude at Langkawi Observatory

    NASA Astrophysics Data System (ADS)

    Zainuddin, Mohd. Zambri; Loon, Chin Wei; Harun, Saedah

    2010-07-01

    Astronomical limiting magnitude is an indicator for astronomer to conduct astronomical measurement at a particular site. It gives an idea to astronomer of that site what magnitude of celestial object can be measured. Langkawi National Observatory (LNO) is situated at Bukit Malut with latitude 6°18' 25'' North and longitude 99°46' 52'' East in Langkawi Island. Sky brightness measurement has been performed at this site using the standard astronomical technique. The value of the limiting magnitude measured is V = 18.6+/-1.0 magnitude. This will indicate that astronomical measurement at Langkawi observatory can only be done for celestial objects having magnitude less than V = 18.6 magnitudes.

  16. 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.

  17. 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.

  18. Determination of the meteor limiting magnitude

    NASA Astrophysics Data System (ADS)

    Kingery, A.; Blaauw, R. C.

    2017-09-01

    We present our method to calculate the meteor limiting magnitude. The limiting meteor magnitude defines the faintest magnitude at which all meteors are still detected by a given system. An accurate measurement of the limiting magnitude is important in order to calculate the meteoroid flux from a meteor shower or sporadic source. Since meteor brightness is linked to meteor mass, the limiting magnitude is needed to calculate the limiting mass of the meteor flux measurement. The mass distribution of meteoroids is thought to follow a power law, thus being slightly off in the limiting magnitude can have a significant effect on the measured flux. Sky conditions can change on fairly short timescales; therefore one must monitor the meteor limiting magnitude at regular intervals throughout the night, rather than just measuring it once. We use the stellar limiting magnitude as a proxy of the meteor limiting magnitude. Our method for determining the stellar limiting magnitude and how we transform it into the meteor limiting magnitude is presented. These methods are currently applied to NASA's wide-field meteor camera network to determine nightly fluxes, but are applicable to other camera networks.

  19. 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.

  20. 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.

  1. Tratamiento canonico del problema de Poincaré. Movimiento del polo.

    NASA Astrophysics Data System (ADS)

    Romero, P.; Sevilla, M. J.

    The rotational motion for a rigid Earth model with a homogeneous liquid core has been obtained using Hamilton's equations. From the canonical equations for the precessional und nutational motions in an inertial frame, the corresponding equations in an Earth fixed frame are deduced. The linearized equations obtained for polar motion and liquid core motion are equivalent to the Moritz's equations (1980).

  2. Developmental Foundations of Children's Fraction Magnitude Knowledge.

    PubMed

    Mou, Yi; Li, Yaoran; Hoard, Mary K; Nugent, Lara D; Chu, Felicia W; Rouder, Jeffrey N; Geary, David C

    2016-01-01

    The conceptual insight that fractions represent magnitudes is a critical yet daunting step in children's mathematical development, and the knowledge of fraction magnitudes influences children's later mathematics learning including algebra. In this study, longitudinal data were analyzed to identify the mathematical knowledge and domain-general competencies that predicted 8(th) and 9(th) graders' (n=122) knowledge of fraction magnitudes and its cross-grade gains. Performance on the fraction magnitude measures predicted 9(th) grade algebra achievement. Understanding and fluently identifying the numerator-denominator relation in 7(th) grade emerged as the key predictor of later fraction magnitudes knowledge in both 8(th) and 9(th) grades. Competence at using fraction procedures, knowledge of whole number magnitudes, and the central executive contributed to 9(th) but not 8(th) graders' fraction magnitude knowledge, and knowledge of whole number magnitude contributed to cross-grade gains. The key results suggest fluent processing of numerator-denominator relations presages students' understanding of fractions as magnitudes and that the integration of whole number and fraction magnitudes occurs gradually.

  3. A Bayesian perspective on magnitude estimation.

    PubMed

    Petzschner, Frederike H; Glasauer, Stefan; Stephan, Klaas E

    2015-05-01

    Our representation of the physical world requires judgments of magnitudes, such as loudness, distance, or time. Interestingly, magnitude estimates are often not veridical but subject to characteristic biases. These biases are strikingly similar across different sensory modalities, suggesting common processing mechanisms that are shared by different sensory systems. However, the search for universal neurobiological principles of magnitude judgments requires guidance by formal theories. Here, we discuss a unifying Bayesian framework for understanding biases in magnitude estimation. This Bayesian perspective enables a re-interpretation of a range of established psychophysical findings, reconciles seemingly incompatible classical views on magnitude estimation, and can guide future investigations of magnitude estimation and its neurobiological mechanisms in health and in psychiatric diseases, such as schizophrenia.

  4. 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…

  5. Magnitude Anomalies and Propagation of Local Phases

    DTIC Science & Technology

    1983-01-31

    statistically significant variation of magnitude anomalies versus one of this above parameters. A contrario, we observed a significant dependance between...enough to demand a more detailed analysis. III - Local dependance of magnitude anomalies. A smoothing of our data on all quakes originating in the same

  6. 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…

  7. 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,…

  8. 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.

  9. Reward magnitude effects on temporal discrimination

    PubMed Central

    Galtress, Tiffany; Kirkpatrick, Kimberly

    2014-01-01

    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 1, rats were trained to discriminate a short (2 s) vs. a long (8 s) signal followed by testing with intermediate durations. Then, the reward on short or long trials was increased from 1 to 4 pellets in separate groups. Experiment 2 measured the effect of different reward magnitudes associated with the short vs. long signals throughout training. Finally, Experiment 3 controlled for satiety effects during the reward magnitude manipulation phase. A general flattening of the psychophysical function was evident in all three experiments, suggesting that unequal reward magnitudes may disrupt attention to duration. PMID:24965705

  10. 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.

  11. Seismic hazard in Greece. I. Magnitude recurrence

    NASA Astrophysics Data System (ADS)

    Makropoulos, Kostas C.; Burton, Paul W.

    1985-08-01

    Two different methods are applied to the earthquake catalogue for Greece (Makropoulos and Burton, 1981), MB catalogue, to evaluate Greek seismic hazard in terms of magnitude: earthquake strain energy release and Gumbel's third asymptotic distribution of extreme values. It is found that there is a close relationship between results from the two methods. In places where the cumulative strain energy release graphs include at least one well defined cycle of periodicity of strain release, then the parameters of the third type asymptote are well defined with small uncertainties. In almost all cases the magnitude distribution shows a remarkably good third type asymptotic behaviour. The results are presented in the form of graphs and contour maps of annual and 80-year modes, and magnitudes with 70% probability of not being exceeded in the next 50 and 100 years. For six of the most heavily industrial and highly populated centres of Greece magnitude hazard parameters are also derived and examined in more detail, thereby illustrating the direct applicability of the methods in terms of zoning. The close agreement between observed and predicted extreme magnitudes shows that the sample period considered (1900-1978), is long enough to obtain statistically stable estimates. For Athens the upper bound magnitude is found to be 6.7 ± 0.3 (within 100 km) and 6.8 ± 0.4 (100 km) from the two methods respectively, whereas for Corinth an earthquake of magnitude 6.5 has a mean return period of 43 years. Greece as a whole has an upper bound magnitude 8.7 ± 0.6 and earthquakes of a size similar to the 1903 Kithira event ( M ≈ 8.0) have a mean return period of about 200 years. The significantly different maps contouring magnitudes of the annual and 80-year modes result from the fact that each place has its own distribution curvature for magnitude occurrence, and thus they are not a linear extrapolation of each other. However, as longer return periods are considered, these differences

  12. Magnitude M w in metropolitan France

    NASA Astrophysics Data System (ADS)

    Cara, Michel; Denieul, Marylin; Sèbe, Olivier; Delouis, Bertrand; Cansi, Yves; Schlupp, Antoine

    2016-12-01

    The recent seismicity catalogue of metropolitan France Sismicité Instrumentale de l'Hexagone (SI-Hex) covers the period 1962-2009. It is the outcome of a multipartner project conducted between 2010 and 2013. In this catalogue, moment magnitudes (M w) are mainly determined from short-period velocimetric records, the same records as those used by the Laboratoire de Détection Géophysique (LDG) for issuing local magnitudes (M L) since 1962. Two distinct procedures are used, whether M L-LDG is larger or smaller than 4. For M L-LDG >4, M w is computed by fitting the coda-wave amplitude on the raw records. Station corrections and regional properties of coda-wave attenuation are taken into account in the computations. For M L-LDG ≤4, M w is converted from M L-LDG through linear regression rules. In the smallest magnitude range M L-LDG <3.1, special attention is paid to the non-unity slope of the relation between the local magnitudes and M w. All M w determined during the SI-Hex project is calibrated according to reference M w of recent events. As for some small events, no M L-LDG has been determined; local magnitudes issued by other French networks or LDG duration magnitude (M D) are first converted into M L-LDG before applying the conversion rules. This paper shows how the different sources of information and the different magnitude ranges are combined in order to determine an unbiased set of M w for the whole 38,027 events of the catalogue.

  13. Limiting Maximum Magnitude by Fault Dimensions (Invited)

    NASA Astrophysics Data System (ADS)

    Stirling, M. W.

    2010-12-01

    A standard practise of seismic hazard modeling is to combine fault and background seismicity sources to produce a multidisciplinary source model for a region. Background sources are typically modeled with a Gutenberg-Richter magnitude-frequency distribution developed from historical seismicity catalogs, and fault sources are typically modeled with earthquakes that are limited in size by the mapped fault rupture dimensions. The combined source model typically exhibits a Gutenberg-Richter-like distribution due to there being many short faults relative to the number of longer faults. The assumption that earthquakes are limited by the mapped fault dimensions therefore appears to be consistent with the Gutenberg-Richter relationship, one of the fundamental laws of seismology. Recent studies of magnitude-frequency distributions for California and New Zealand have highlighted an excess of fault-derived earthquakes relative to the log-linear extrapolation of the Gutenberg-Richter relationship from the smaller magnitudes (known as the “bulge”). Relaxing the requirement of maximum magnitude being limited by fault dimensions is a possible solution for removing the “bulge” to produce a perfectly log-linear Gutenberg-Richter distribution. An alternative perspective is that the “bulge” does not represent a significant departure from a Gutenberg-Richter distribution, and may simply be an artefact of a small earthquake dataset relative to the more plentiful data at the smaller magnitudes. In other words the uncertainty bounds of the magnitude-frequency distribution at the moderate-to-large magnitudes may be far greater than the size of the “bulge”.

  14. Magnitude and frequency of floods in Alabama

    USGS Publications Warehouse

    Atkins, J. Brian

    1996-01-01

    Methods of estimating flood magnitudes for recurrence intervals of 2, 5, 10, 25, 50, 100, 200, and 500 years are described for rural streams in Alabama that are not affected by regulation or urbanization. Flood-frequency characteristics are presented for 198 gaging stations in Alabama having 10 or more years of record through September 1991, that are used in the regional analysis. Regression relations were developed using generalized least-squares regression techniques to estimate flood magnitude and frequency on ungaged streams as a function of the drainage area of a basin. Sites on gaged streams should be weighted with gaging station data that are presented in the report. Graphical relations of peak discharges to drainage areas are also presented for sites along the Alabama, Black Warrior, Cahaba, Choctawhatchee, Conecub, and Tombigbee Rivers. Equations for estimating flood magnitudes on ungaged urban streams (taken from a previous report) that use drainage area and percentage of impervious cover as independent variables also are given.

  15. The development of a rotational magnitude scale

    NASA Astrophysics Data System (ADS)

    Chow, Bryant; Simonelli, Andrea; Hadziiannou, Celine; Donner, Stefanie; Igel, Heiner

    2017-04-01

    Current surface wave magnitude equations normally take into account only the vertical component of peak ground displacement, and therefore only contributions from Rayleigh waves. Horizontal components contain both Rayleigh and Love waves, which potentially obscure attenuation characteristics. With the advent of rotational ground motion observations from instruments such as ring laser gyroscopes and fibre-optic gyroscopes, it is now possible to determine peak amplitudes of rotations about the vertical axis. At teleseismic distances, these are dominated by Love waves and are in principle unaffected by Rayleigh waves. We aim to use this concept to determine a Love wave based surface wave magnitude equation; with a large database of rotational ground motion events of varying source parameters, we intend to empirically define a rotational magnitude scale and consequently an amplitude decay law for Love waves.

  16. Improving Children's Knowledge of Fraction Magnitudes.

    PubMed

    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.

  17. Representations of the magnitudes of fractions.

    PubMed

    Schneider, Michael; Siegler, Robert S

    2010-10-01

    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, atypical characteristics of the presented fractions might have provoked the use of atypical comparison strategies in that study. In our 3 experiments, university and community college students compared more balanced sets of single-digit and multi-digit fractions and consistently exhibited a logarithmic distance effect. Thus, adults used integrated, analog representations, akin to a mental number line, to compare fraction magnitudes. We interpret differences between the past and present findings in terms of different stimuli eliciting different solution strategies.

  18. Paleostress magnitudes in folded sedimentary rocks

    NASA Astrophysics Data System (ADS)

    Amrouch, Khalid; Beaudoin, Nicolas; Lacombe, Olivier; Bellahsen, Nicolas; Daniel, Jean-Marc

    2011-09-01

    Using Sheep Mountain Anticline (Wyoming, USA) as a case study, we propose a new approach to quantify effective paleo-principal stress magnitudes in the uppermost crust. The proposed mechanical scenario relies on a well-documented kinematic and chronological sequence of development of faults, fractures and microstructures in the folded strata. Paleostress orientations and regimes as well as differential stress magnitudes based on calcite twinning paleopiezometry are combined with rock mechanics data in a Mohr construction to derive principal stress magnitudes related to the successive steps of layer-parallel shortening and to late stage fold tightening. Such quantification also provides original insights into the evolution of the fluid (over)pressure and amount of syn-folding erosion.

  19. A second type of magnitude effect: Reinforcer magnitude differentiates delay discounting between substance users and controls.

    PubMed

    Mellis, Alexandra M; Woodford, Alina E; Stein, Jeffrey S; Bickel, Warren K

    2017-01-01

    Basic research on delay discounting, examining preference for smaller-sooner or larger-later reinforcers, has demonstrated a variety of findings of considerable generality. One of these, the magnitude effect, is the observation that individuals tend to exhibit greater preference for the immediate with smaller magnitude reinforcers. Delay discounting has also proved to be a useful marker of addiction, as demonstrated by the highly replicated finding of greater discounting rates in substance users compared to controls. However, some research on delay discounting rates in substance users, particularly research examining discounting of small-magnitude reinforcers, has not found significant differences compared to controls. Here, we hypothesize that the magnitude effect could produce ceiling effects at small magnitudes, thus obscuring differences in delay discounting between groups. We examined differences in discounting between high-risk substance users and controls over a broad range of magnitudes of monetary amounts ($0.10, $1.00, $10.00, $100.00, and $1000.00) in 116 Amazon Mechanical Turk workers. We found no significant differences in discounting rates between users and controls at the smallest reinforcer magnitudes ($0.10 and $1.00) and further found that differences became more pronounced as magnitudes increased. These results provide an understanding of a second form of the magnitude effect: That is, differences in discounting between populations can become more evident as a function of reinforcer magnitude.

  20. Saccadic Compression of Symbolic Numerical Magnitude

    PubMed Central

    Binda, Paola; Morrone, M. Concetta; Bremmer, Frank

    2012-01-01

    Stimuli flashed briefly around the time of saccadic eye movements are subject to complex distortions: compression of space and time; underestimate of numerosity. Here we show that saccadic distortions extend to abstract quantities, affecting the representation of symbolic numerical magnitude. Subjects consistently underestimated the results of rapidly computed mental additions and subtractions, when the operands were briefly displayed before a saccade. However, the recognition of the number symbols was unimpaired. These results are consistent with the hypothesis of a common, abstract metric encoding magnitude along multiple dimensions. They suggest that a surprising link exists between the preparation of action and the representation of abstract quantities. PMID:23166720

  1. 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.

  2. Incentive theory: IV. Magnitude of reward

    PubMed Central

    Killeen, Peter R.

    1985-01-01

    Incentive theory is successfully applied to data from experiments in which the amount of food reward is varied. This is accomplished by assuming that incentive value is a negatively accelerated function of reward duration. The interaction of the magnitude of a reward with its delay is confirmed, and the causes and implications of this interaction are discussed. PMID:16812421

  3. Improving Children's Knowledge of Fraction Magnitudes

    ERIC Educational Resources Information Center

    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…

  4. Geometric Derivation of Radial Acceleration Magnitude.

    ERIC Educational Resources Information Center

    Kraft, David W.; Motz, Lloyd

    1995-01-01

    Standard treatments of uniform circular motion generally employ a combination of geometric and kinematic arguments to obtain the magnitude of radial acceleration. Presents a novel approach to the geometric portion of the derivation that uses the property that vectors can be translated parallel to themselves. (JRH)

  5. Improving Children's Knowledge of Fraction Magnitudes

    ERIC Educational Resources Information Center

    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…

  6. Interaction of Number Magnitude and Auditory Localization.

    PubMed

    Golob, Edward J; Lewald, Jörg; Jungilligens, Johannes; Getzmann, Stephan

    2016-01-01

    The interplay of perception and memory is very evident when we perceive and then recognize familiar stimuli. Conversely, information in long-term memory may also influence how a stimulus is perceived. Prior work on number cognition in the visual modality has shown that in Western number systems long-term memory for the magnitude of smaller numbers can influence performance involving the left side of space, while larger numbers have an influence toward the right. Here, we investigated in the auditory modality whether a related effect may bias the perception of sound location. Subjects (n = 28) used a swivel pointer to localize noise bursts presented from various azimuth positions. The noise bursts were preceded by a spoken number (1-9) or, as a nonsemantic control condition, numbers that were played in reverse. The relative constant error in noise localization (forward minus reversed speech) indicated a systematic shift in localization toward more central locations when the number was smaller and toward more peripheral positions when the preceding number magnitude was larger. These findings do not support the traditional left-right number mapping. Instead, the results may reflect an overlap between codes for number magnitude and codes for sound location as implemented by two channel models of sound localization, or possibly a categorical mapping stage of small versus large magnitudes. © The Author(s) 2015.

  7. 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.

  8. From 'sense of number' to 'sense of magnitude' - The role of continuous magnitudes in numerical cognition.

    PubMed

    Leibovich, Tali; Katzin, Naama; Harel, Maayan; Henik, Avishai

    2016-08-17

    In this review, we are pitting two theories against each other: the more accepted theory-the 'number sense' theory-suggesting that a sense of number is innate and non-symbolic numerosity is being processed independently of continuous magnitudes (e.g., size, area, density); and the newly emerging theory suggesting that (1) both numerosities and continuous magnitudes are processed holistically when comparing numerosities, and (2) a sense of number might not be innate. In the first part of this review, we discuss the 'number sense' theory. Against this background, we demonstrate how the natural correlation between numerosities and continuous magnitudes makes it nearly impossible to study non-symbolic numerosity processing in isolation from continuous magnitudes, and therefore the results of behavioral and imaging studies with infants, adults and animals can be explained, at least in part, by relying on continuous magnitudes. In the second part, we explain the 'sense of magnitude' theory and review studies that directly demonstrate that continuous magnitudes are more automatic and basic than numerosities. Finally, we present outstanding questions. Our conclusion is that there is not enough convincing evidence to support the number sense theory anymore. Therefore, we encourage researchers not to assume that number sense is simply innate, but to put this hypothesis to the test, and to consider if such an assumption is even testable in light of the correlation of numerosity and continuous magnitudes.

  9. 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…

  10. 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.

  11. Absolute magnitudes and kinematic properties of Cepheids.

    NASA Astrophysics Data System (ADS)

    Wilson, T. D.; Jefferys, W. H.; Barnes, T. G., III; Hawley, S. L.

    A maximum-likelihood statistical parallax analysis of classical Cepheids has been performed to determine the relative solar motion, Oort constants, velocity ellipsoid parameters, and zero points of the PL and PLC relations. The analysis is based upon 90 proper motions drawn from the list of Karimova and Pavlovskaya 1981 and upon the analytical approach of Hawley et al. 1986. The authors' results give a best estimate for the mean absolute magnitude of Cepheids at log P = 0.8 of = -3.46±0.33 mag. This estimate for the Cepheid absolute magnitude zero point is highly stable against refinements in the mathematical technique and against additional Cepheid proper motion data of quality similar to the existing proper motions. Improvement in this value will likely come only from a marked improvement in the quality of the Cepheid proper motions.

  12. 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.

  13. The Ml Magnitude Scale In Italy

    NASA Astrophysics Data System (ADS)

    Gasperini, P.; Lolli, B.; Filippucci, M.; de Simoni, B.

    To improve the reliability of Ml magnitude estimates in Italy, we have updated the database of real Wood-Anderson (WA) and of simulated Wood Anderson (SWA) am- plitudes recently revised by Gasperini (2002). This was done by the re-reading of orig- inal WA seismograms, made available by the SISMOS Project of the Istituto Nazionale di Geofisica (INGV), as well as by the analysis of further Very Broad Band (VBB) recordings of the MEDNET network of INGV for the period from 1996 to 1998. The full operability, in the last five years, of a VBB station located exactly at the same site (TRI) of a former WA instrument allowed us to reliably infer a new attenuation function from the joined WA and SWA dataset. We found a significant deviation of the attenuation law from the standard Richter table at distances larger than 400 km where the latter overestimates the magnitude up to about 0.3 units. We also computed regionalized attenuation functions accounting for the differences in the propagation properties of seismic waves between the Adriatic (less attenuating) and Tyrrhenian (more attenuating) sides of the Italian peninsula. Using this improved Ml magnitude database we were also able to further improve the computation of duration (Md) and amplitude (Ma) magnitudes computed from short period vertical seismometers of the INGV as well as to analyze the time variation of the station calibrations. We found that the absolute amplification of INGV stations is underestimated almost exactly by a factor 2 starting from the entering upon in operation of the digital acquisition system at INGV in middle 1984.

  14. 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.

  15. Maximum magnitude earthquakes induced by fluid injection

    USGS Publications Warehouse

    McGarr, Arthur F.

    2014-01-01

    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.

  16. 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.

  17. 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.

    2017-01-01

    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.

  18. 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.

  19. Magnitude and frequency of floods in Arkansas

    USGS Publications Warehouse

    Hodge, Scott A.; Tasker, Gary D.

    1995-01-01

    Methods are presented for estimating the magnitude and frequency of peak discharges of streams in Arkansas. Regression analyses were developed in which a stream's physical and flood characteristics were related. Four sets of regional regression equations were derived to predict peak discharges with selected recurrence intervals of 2, 5, 10, 25, 50, 100, and 500 years on streams draining less than 7,770 square kilometers. The regression analyses indicate that size of drainage area, main channel slope, mean basin elevation, and the basin shape factor were the most significant basin characteristics that affect magnitude and frequency of floods. The region of influence method is included in this report. This method is still being improved and is to be considered only as a second alternative to the standard method of producing regional regression equations. This method estimates unique regression equations for each recurrence interval for each ungaged site. The regression analyses indicate that size of drainage area, main channel slope, mean annual precipitation, mean basin elevation, and the basin shape factor were the most significant basin and climatic characteristics that affect magnitude and frequency of floods for this method. Certain recommendations on the use of this method are provided. A method is described for estimating the magnitude and frequency of peak discharges of streams for urban areas in Arkansas. The method is from a nationwide U.S. Geeological Survey flood frequency report which uses urban basin characteristics combined with rural discharges to estimate urban discharges. Annual peak discharges from 204 gaging stations, with drainage areas less than 7,770 square kilometers and at least 10 years of unregulated record, were used in the analysis. These data provide the basis for this analysis and are published in the Appendix of this report as supplemental data. Large rivers such as the Red, Arkansas, White, Black, St. Francis, Mississippi, and

  20. 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).

  1. Resurgence and alternative-reinforcer magnitude.

    PubMed

    Craig, Andrew R; Browning, Kaitlyn O; Nall, Rusty W; Marshall, Ciara M; Shahan, Timothy A

    2017-03-01

    Resurgence is defined as an increase in the frequency of a previously reinforced target response when an alternative source of reinforcement is suspended. Despite an extensive body of research examining factors that affect resurgence, the effects of alternative-reinforcer magnitude have not been examined. Thus, the present experiments aimed to fill this gap in the literature. In Experiment 1, rats pressed levers for single-pellet reinforcers during Phase 1. In Phase 2, target-lever pressing was extinguished, and alternative-lever pressing produced either five-pellet, one-pellet, or no alternative reinforcement. In Phase 3, alternative reinforcement was suspended to test for resurgence. Five-pellet alternative reinforcement produced faster elimination and greater resurgence of target-lever pressing than one-pellet alternative reinforcement. In Experiment 2, effects of decreasing alternative-reinforcer magnitude on resurgence were examined. Rats pressed levers and pulled chains for six-pellet reinforcers during Phases 1 and 2, respectively. In Phase 3, alternative reinforcement was decreased to three pellets for one group, one pellet for a second group, and suspended altogether for a third group. Shifting from six-pellet to one-pellet alternative reinforcement produced as much resurgence as suspending alternative reinforcement altogether, while shifting from six pellets to three pellets did not produce resurgence. These results suggest that alternative-reinforcer magnitude has effects on elimination and resurgence of target behavior that are similar to those of alternative-reinforcer rate. Thus, both suppression of target behavior during alternative reinforcement and resurgence when conditions of alternative reinforcement are altered may be related to variables that affect the value of the alternative-reinforcement source.

  2. 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).

  3. 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.

  4. Precise Relative Earthquake Magnitudes from Cross Correlation

    DOE PAGES

    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.

  5. Precise Relative Earthquake Magnitudes from Cross Correlation

    SciTech Connect

    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.

  6. Strong motion duration and earthquake magnitude relationships

    SciTech Connect

    Salmon, M.W.; Short, S.A.; Kennedy, R.P.

    1992-06-01

    Earthquake duration is the total time of ground shaking from the arrival of seismic waves until the return to ambient conditions. Much of this time is at relatively low shaking levels which have little effect on seismic structural response and on earthquake damage potential. As a result, a parameter termed ``strong motion duration`` has been defined by a number of investigators to be used for the purpose of evaluating seismic response and assessing the potential for structural damage due to earthquakes. This report presents methods for determining strong motion duration and a time history envelope function appropriate for various evaluation purposes, for earthquake magnitude and distance, and for site soil properties. There are numerous definitions of strong motion duration. For most of these definitions, empirical studies have been completed which relate duration to earthquake magnitude and distance and to site soil properties. Each of these definitions recognizes that only the portion of an earthquake record which has sufficiently high acceleration amplitude, energy content, or some other parameters significantly affects seismic response. Studies have been performed which indicate that the portion of an earthquake record in which the power (average rate of energy input) is maximum correlates most closely with potential damage to stiff nuclear power plant structures. Hence, this report will concentrate on energy based strong motion duration definitions.

  7. Floods in Utah, magnitude and frequency

    USGS Publications Warehouse

    Berwick, Vernon K.

    1962-01-01

    This report presents a procedure for estimating the magnitude and frequency of floods, within the range of the base data, for any site, gaged or ungaged. From the relation of annual floods to the mean annual flood, a composite frequency curve was derived for recurrence intervals of 1.1 to 50 years. For regions of similar hydrologic characteristics, curves were developed by multiple correlation to express the relation of mean annual flood to drainage area and mean altitude. The records of gaging stations having 5 or more years of record were used as base data when the natural conditions of streamflow are not affected by works of man. For major rivers where the flow is affected by diversion or regulation, separate analyses were made for each stream. The results may be applied to any area in Utah, except the Great Salt Lake Desert and a small area of the State in the Snake River basin.

  8. Violence against women: global scope and magnitude.

    PubMed

    Watts, Charlotte; Zimmerman, Cathy

    2002-04-06

    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.

  9. Child prostitution: magnitude and related problems.

    PubMed

    Ayalew, T; Berhane, Y

    2000-07-01

    In Ethiopia, very little is known about prostitution in general and about child prostitution in particular. The objective of this study was to determine the magnitude of child prostitution and to identify problems associated with it. A cross-sectional study design was utilized. Data were collected using structured questionnaire. A total of 650 commercial sex workers were interviewed. Eighty eight (13.5%) were below the age of 18 years at the time of data collection. At the time of joining prostitution 268 (41.2%) were under 18 years of age. Poverty, disagreement with family, and peer influence were the major reasons leading to prostitution. Child prostitutes were likely to be victim of physical violence [OR = (95% C.I.) = 1.93(1.18,3.15)] and sexual violence [OR = (95% C.I.) = 2.20(1.36,3.35)] compared to adult prostitutes. Child prostitutes were about five times more likely to desire rejoining their family than the adult prostitutes [OR = (95% C.I) = 5.47(3.01;9.93)]. Strategies need to be developed to rescue child prostitutes from on-job violence, and to establish a rehabilitation program for those interested to discontinue prostitution along with efforts to minimize entry into prostitution.

  10. 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).

  11. Magnitude-based scaling of tsunami propagation

    NASA Astrophysics Data System (ADS)

    Simanjuntak, M. Arthur; Greenslade, Diana J. M.

    2011-07-01

    Most current operational tsunami prediction systems are based upon databases of precomputed tsunami scenarios, where some form of linear scaling is applied to the precomputed model runs in order to represent specific earthquake magnitudes. This can introduce errors due to assumptions made about the rupture width and possible effects on dispersion. In this paper, we perform a series of numerical experiments on uniform depth domains, using the Method of Splitting Tsunamis (MOST) model, and develop estimates of the maximum error that an assumed discrepancy in the width of a rupture will produce in the resulting field of maximum tsunami amplitude. This estimate was produced from fitting the decay of maximum amplitude with normalized distance for various resolutions of the source widths to the grid size, resulting in a simple power law whose coefficients effectively vary with wavelength resolution. This provides a quantification of the effect that linear scaling of precomputed scenarios will have on forecasts of tsunami amplitude. This estimate of scaling bias is investigated in relation to the scenario database that is currently in use within the Joint Australian Tsunami Warning Centre.

  12. Symbolic magnitude modulates perceptual strength in binocular rivalry.

    PubMed

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

    2011-06-01

    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 known size increases with their magnitude. Importantly, variations in symbolic magnitude acted like variations in luminance contrast: we found that an increase in numerical magnitude of adding one lead to an equivalent increase in perceptual dominance as a contrast increment of 0.32%. Our results support the claim that magnitude is extracted automatically, since the increase in perceptual dominance came about in the absence of a magnitude-related task. Our findings show that symbolic, acculturated knowledge about magnitude interacts with visual perception and affects perception in a manner similar to lower-level aspects of magnitude such as luminance contrast.

  13. 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.

  14. Total Galaxy Magnitudes and Effective Radii from Petrosian Magnitudes and Radii

    NASA Astrophysics Data System (ADS)

    Graham, Alister W.; Driver, Simon P.; Petrosian, Vahé; Conselice, Christopher J.; Bershady, Matthew A.; Crawford, Steven M.; Goto, Tomotsugu

    2005-10-01

    Petrosian magnitudes were designed to help with the difficult task of determining a galaxy's total light. Although these magnitudes [taken here as the flux within 2RP, with the inverted Petrosian index 1/η(RP)=0.2] can represent most of an object's flux, they do of course miss the light outside the Petrosian aperture (2RP). The size of this flux deficit varies monotonically with the shape of a galaxy's light profile, i.e., its concentration. In the case of a de Vaucouleurs R1/4 profile, the deficit is 0.20 mag; for an R1/8 profile this figure rises to 0.50 mag. Here we provide a simple method for recovering total (Sérsic) magnitudes from Petrosian magnitudes using only the galaxy concentration (R90/R50 or R80/R20) within the Petrosian aperture. The corrections hold to the extent that Sérsic's model provides a good description of a galaxy's luminosity profile. We show how the concentration can also be used to convert Petrosian radii into effective half-light radii, enabling a robust measure of the mean effective surface brightness. Our technique is applied to the Sloan Digital Sky Survey Data Release 2 (SDSS DR2) Petrosian parameters, yielding good agreement with the total magnitudes, effective radii, and mean effective surface brightnesses obtained from the New York University Value-Added Galaxy Catalog Sérsic R1/n fits by Blanton and coworkers. Although the corrective procedure described here is specifically applicable to the SDSS DR2 and DR3, it is generally applicable to all imaging data where any Petrosian index and concentration can be constructed.

  15. 101 Short Problems from EQUALS = 101 Problemas Cortos del programma EQUALS.

    ERIC Educational Resources Information Center

    Stenmark, Jean Kerr, Ed.

    EQUALS is a teacher advisory program that helps elementary and secondary educators acquire methods and materials to attract minority and female students to mathematics. The program supports a problem-solving approach to mathematics, including having students working in groups, using active assessment methods, and incorporating a broad mathematics…

  16. 101 Short Problems from EQUALS = 101 Problemas Cortos del programma EQUALS.

    ERIC Educational Resources Information Center

    Stenmark, Jean Kerr, Ed.

    EQUALS is a teacher advisory program that helps elementary and secondary educators acquire methods and materials to attract minority and female students to mathematics. The program supports a problem-solving approach to mathematics, including having students working in groups, using active assessment methods, and incorporating a broad mathematics…

  17. Practical Local Magnitude Calculation for Local Networks

    NASA Astrophysics Data System (ADS)

    Tunc, B.; Tunc, S.; Caka, D.

    2012-12-01

    In this study, we developed a Matlab application (Ml_Calc) to calculate local magnitude (Ml) for small institudes which has just one or more seismic stations. Ml_Calc algorithm suitable for velocity or acceleration sensors' data obtained by Güralp Systems digitizers. The selected earthquake data can be transferred from SCREAM software to Ml_Calc online or offline. The Ml_Calc algorithm provides two types of solutions for distance, one of them is P-S time differences and the other one is epicentre of earthquake and station coordinates, if earthquake is known. During Ml calculation, instrument correction has been removed and converted to real displacement in milimeter. The obtained displacement data converted to Wood Anderson Seismometer output by using Z=[0;0]; P=[-6.28+4.71j; -6.28-4.71j]; A0=[2080]. Obtained maximum displacement amplitude (A) and distances (dist) used in formula (1) for distances less than 200km and formula (2) for more than 200km. Ml=log10(A)-(-1.118-0.0647*dist+0.00071*dist2-3.39E-6*dist3+5.71e-9*dist4) (1) Ml=log10(A)+(2.1173+0.0082*dist-0.0000059628*dist2) (2) Ml_Calc is a software that easy to implement, can be used for educational purpose and user friendly. Due to this characteristics, Ml_Calc software offered a practical solution to individual users to Ml calculation.

  18. Nonlinear Susceptibility Magnitude Imaging of Magnetic Nanoparticles.

    PubMed

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

    2015-03-15

    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 (R(2) = 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 (R(2) > 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.

  19. The moment magnitude M w and the energy magnitude M e: common roots and differences

    NASA Astrophysics Data System (ADS)

    Bormann, Peter; di Giacomo, Domenico

    2011-04-01

    Starting from the classical empirical magnitude-energy relationships, in this article, the derivation of the modern scales for moment magnitude M w and energy magnitude M e is outlined and critically discussed. The formulas for M w and M e calculation are presented in a way that reveals, besides the contributions of the physically defined measurement parameters seismic moment M 0 and radiated seismic energy E S, the role of the constants in the classical Gutenberg-Richter magnitude-energy relationship. Further, it is shown that M w and M e are linked via the parameter Θ = log( E S/ M 0), and the formula for M e can be written as M e = M w + (Θ + 4.7)/1.5. This relationship directly links M e with M w via their common scaling to classical magnitudes and, at the same time, highlights the reason why M w and M e can significantly differ. In fact, Θ is assumed to be constant when calculating M w. However, variations over three to four orders of magnitude in stress drop Δ σ (as well as related variations in rupture velocity V R and seismic wave radiation efficiency η R) are responsible for the large variability of actual Θ values of earthquakes. As a result, for the same earthquake, M e may sometimes differ by more than one magnitude unit from M w. Such a difference is highly relevant when assessing the actual damage potential associated with a given earthquake, because it expresses rather different static and dynamic source properties. While M w is most appropriate for estimating the earthquake size (i.e., the product of rupture area times average displacement) and thus the potential tsunami hazard posed by strong and great earthquakes in marine environs, M e is more suitable than M w for assessing the potential hazard of damage due to strong ground shaking, i.e., the earthquake strength. Therefore, whenever possible, these two magnitudes should be both independently determined and jointly considered. Usually, only M w is taken as a unified magnitude in many

  20. 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

  1. Moment Magnitude ( M W) and Local Magnitude ( M L) Relationship for Earthquakes in Northeast India

    NASA Astrophysics Data System (ADS)

    Baruah, Santanu; Baruah, Saurabh; Bora, P. K.; Duarah, R.; Kalita, Aditya; Biswas, Rajib; Gogoi, N.; Kayal, J. R.

    2012-11-01

    An attempt has been made to examine an empirical relationship between moment magnitude ( M W) and local magnitude ( M L) for the earthquakes in the northeast Indian region. Some 364 earthquakes that were recorded during 1950-2009 are used in this study. Focal mechanism solutions of these earthquakes include 189 Harvard-CMT solutions ( M W ≥ 4.0) for the period 1976-2009, 61 published solutions and 114 solutions obtained for the local earthquakes (2.0 ≤ M L ≤ 5.0) recorded by a 27-station permanent broadband network during 2001-2009 in the region. The M W- M L relationships in seven selected zones of the region are determined by linear regression analysis. A significant variation in the M W- M L relationship and its zone specific dependence are reported here. It is found that M W is equivalent to M L with an average uncertainty of about 0.13 magnitude units. A single relationship is, however, not adequate to scale the entire northeast Indian region because of heterogeneous geologic and geotectonic environments where earthquakes occur due to collisions, subduction and complex intra-plate tectonics.

  2. Numerical magnitude affects temporal memories but not time encoding.

    PubMed

    Cai, Zhenguang G; Wang, Ruiming

    2014-01-01

    Previous research has suggested that the perception of time is influenced by concurrent magnitude information (e.g., numerical magnitude in digits, spatial distance), but the locus of the effect is unclear, with some findings suggesting that concurrent magnitudes such as space affect temporal memories and others suggesting that numerical magnitudes in digits affect the clock speed during time encoding. The current paper reports 6 experiments in which participants perceived a stimulus duration and then reproduced it. We showed that though a digit of a large magnitude (e.g., 9), relative to a digit of a small magnitude (e.g., 2), led to a longer reproduced duration when the digits were presented during the perception of the stimulus duration, such a magnitude effect disappeared when the digits were presented during the reproduction of the stimulus duration. These findings disconfirm the account that large numerical magnitudes accelerate the speed of an internal clock during time encoding, as such an account incorrectly predicts that a large numerical magnitude should lead to a shorter reproduced duration when presented during reproduction. Instead, the findings suggest that numerical magnitudes, like other magnitudes such as space, affect temporal memories when numerical magnitudes and temporal durations are concurrently held in memory. Under this account, concurrent numerical magnitudes have the chance to influence the memory of the perceived duration when they are presented during perception but not when they are presented at the reproduction stage.

  3. The modulation of implicit magnitude on time estimates.

    PubMed

    Ma, Qingxia; Yang, Zhen; Zhang, Zhijie

    2012-01-01

    Studies in time and quantity have shown that explicit magnitude (e.g. Arabic numerals, luminance, or size) modulates time estimates with smaller magnitude biasing the judgment of time towards underestimation and larger magnitude towards overestimation. However, few studies have examined the effect of implicit magnitude on time estimates. The current study used a duration estimation task to investigate the effects of implicit magnitude on time estimation in three experiments. During the duration estimation task, the target words named objects of various lengths (Experiment 1), weights (Experiment 2) and volumes (Experiment 3) were presented on the screen and participants were asked to reproduce the amount of time the words remained on the screen via button presses. Results indicated that the time estimates were modulated by the implicit magnitude of the word's referent with words named objects of smaller magnitude (shorter, lighter, or smaller) being judged to last a shorter time, and words named objects of greater magnitude (longer, heavier, or bigger) being judged to last a longer time. These findings were consistent with previous studies examining the effect of implicit spatial length on time estimates. More importantly, current results extended the implicit magnitude of length to the implicit magnitude of weight and volume and demonstrated a functional interaction between time and implicit magnitude in all three aspects of quantity, suggesting a common generalized magnitude system. These results provided new evidence to support a theory of magnitude (ATOM).

  4. REM (relative element magnitude): program explanation and computer program listing

    USGS Publications Warehouse

    VanTrump, George; Alminas, Henry V.

    1978-01-01

    The REM (relative element magnitude) program is designed as an aid in the characterization of geochemical anomalies. The program ranks the magnitudes of anomalies of individual elements within a multielement geochemical anomaly.

  5. Exploring the relationship between the magnitudes of seismic events

    NASA Astrophysics Data System (ADS)

    Spassiani, Ilaria; Sebastiani, Giovanni

    2016-02-01

    The distribution of the magnitudes of seismic events is generally assumed to be independent on past seismicity. However, by considering events in causal relation, for example, mother-daughter, it seems natural to assume that the magnitude of a daughter event is conditionally dependent on one of the corresponding mother events. In order to find experimental evidence supporting this hypothesis, we analyze different catalogs, both real and simulated, in two different ways. From each catalog, we obtain the law of the magnitude of the triggered events by kernel density. The results obtained show that the distribution density of the magnitude of the triggered events varies with the magnitude of their corresponding mother events. As the intuition suggests, an increase of the magnitude of the mother events induces an increase of the probability of having "high" values of the magnitude of the triggered events. In addition, we see a statistically significant increasing linear dependence of the magnitude means.

  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, 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...

  8. 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…

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. 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.

  14. 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.

  15. 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…

  16. Functional shape of the earthquake frequency-magnitude distribution and completeness magnitude

    NASA Astrophysics Data System (ADS)

    Mignan, A.

    2012-08-01

    We investigated the functional shape of the earthquake frequency-magnitude distribution (FMD) to identify its dependence on the completeness magnitude Mc. The FMD takes the form N(m) ∝ exp(-βm)q(m) where N(m) is the event number, m the magnitude, exp(-βm) the Gutenberg-Richter law and q(m) a detection function. q(m) is commonly defined as the cumulative Normal distribution to describe the gradual curvature of bulk FMDs. Recent results however suggest that this gradual curvature is due to Mc heterogeneities, meaning that the functional shape of the elemental FMD has yet to be described. We propose a detection function of the form q(m) = exp(κ(m - Mc)) for m < Mc and q(m) = 1 for m ≥ Mc, which leads to an FMD of angular shape. The two FMD models are compared in earthquake catalogs from Southern California and Nevada and in synthetic catalogs. We show that the angular FMD model better describes the elemental FMD and that the sum of elemental angular FMDs leads to the gradually curved bulk FMD. We propose an FMD shape ontology consisting of 5 categories depending on the Mc spatial distribution, from Mc constant to Mc highly heterogeneous: (I) Angular FMD, (II) Intermediary FMD, (III) Intermediary FMD with multiple maxima, (IV) Gradually curved FMD and (V) Gradually curved FMD with multiple maxima. We also demonstrate that the gradually curved FMD model overestimates Mc. This study provides new insights into earthquake detectability properties by using seismicity as a proxy and the means to accurately estimate Mc in any given volume.

  17. Development of an Empirical Local Magnitude Formula for Northern Oklahoma

    NASA Astrophysics Data System (ADS)

    Spriggs, N.; Karimi, S.; Moores, A. O.

    2015-12-01

    In this paper we focus on determining a local magnitude formula for northern Oklahoma that is unbiased with distance by empirically constraining the attenuation properties within the region of interest based on the amplitude of observed seismograms. For regional networks detecting events over several hundred kilometres, distance correction terms play an important role in determining the magnitude of an event. Standard distance correction terms such as Hutton and Boore (1987) may have a significant bias with distance if applied in a region with different attenuation properties, resulting in an incorrect magnitude. We have presented data from a regional network of broadband seismometers installed in bedrock in northern Oklahoma. The events with magnitude in the range of 2.0 and 4.5, distributed evenly across this network are considered. We find that existing models show a bias with respect to hypocentral distance. Observed amplitude measurements demonstrate that there is a significant Moho bounce effect that mandates the use of a trilinear attenuation model in order to avoid bias in the distance correction terms. We present two different approaches of local magnitude calibration. The first maintains the classic definition of local magnitude as proposed by Richter. The second method calibrates local magnitude so that it agrees with moment magnitude where a regional moment tensor can be computed. To this end, regional moment tensor solutions and moment magnitudes are computed for events with magnitude larger than 3.5 to allow calibration of local magnitude to moment magnitude. For both methods the new formula results in magnitudes systematically lower than previous values computed with Eaton's (1992) model. We compare the resulting magnitudes and discuss the benefits and drawbacks of each method. Our results highlight the importance of correct calibration of the distance correction terms for accurate local magnitude assessment in regional networks.

  18. 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

  19. Developmental Foundations of Children’s Fraction Magnitude Knowledge

    PubMed Central

    Mou, Yi; Li, Yaoran; Hoard, Mary K.; Nugent, Lara D.; Chu, Felicia W.; Rouder, Jeffrey N.; Geary, David C.

    2016-01-01

    The conceptual insight that fractions represent magnitudes is a critical yet daunting step in children’s mathematical development, and the knowledge of fraction magnitudes influences children’s later mathematics learning including algebra. In this study, longitudinal data were analyzed to identify the mathematical knowledge and domain-general competencies that predicted 8th and 9th graders’ (n=122) knowledge of fraction magnitudes and its cross-grade gains. Performance on the fraction magnitude measures predicted 9th grade algebra achievement. Understanding and fluently identifying the numerator-denominator relation in 7th grade emerged as the key predictor of later fraction magnitudes knowledge in both 8th and 9th grades. Competence at using fraction procedures, knowledge of whole number magnitudes, and the central executive contributed to 9th but not 8th graders’ fraction magnitude knowledge, and knowledge of whole number magnitude contributed to cross-grade gains. The key results suggest fluent processing of numerator-denominator relations presages students’ understanding of fractions as magnitudes and that the integration of whole number and fraction magnitudes occurs gradually. PMID:27773965

  20. Comparison enhances size sensitivity: neural correlates of outcome magnitude processing.

    PubMed

    Luo, Qiuling; Qu, Chen

    2013-01-01

    Magnitude is a critical feature of outcomes. In the present study, two event-related potential (ERP) experiments were implemented to explore the neural substrates of outcome magnitude processing. In Experiment 1, we used an adapted gambling paradigm where physical area symbols were set to represent potential relative outcome magnitudes in order to exclude the possibility that the participants would be ignorant of the magnitudes. The context was manipulated as total monetary amount: ¥4 and ¥40. In these two contexts, the relative outcome magnitudes were ¥1 versus ¥3, and ¥10 versus ¥30, respectively. Experiment 2, which provided two area symbols with similar outcome magnitudes, was conducted to exclude the possible interpretation of physical area symbol for magnitude effect of feedback-related negativity (FRN) in Experiment 1. Our results showed that FRN responded to the relative outcome magnitude but not to the context or area symbol, with larger amplitudes for relatively small outcomes. A larger FRN effect (the difference between losses and wins) was found for relatively large outcomes than relatively small outcomes. Relatively large outcomes evoked greater positive ERP waves (P300) than relatively small outcomes. Furthermore, relatively large outcomes in a high amount context elicited a larger P300 than those in a low amount context. The current study indicated that FRN is sensitive to variations in magnitude. Moreover, relative magnitude was integrated in both the early and late stages of feedback processing, while the monetary amount context was processed only in the late stage of feedback processing.

  1. Developmental Dyscalculia in Adults: Beyond Numerical Magnitude Impairment.

    PubMed

    De Visscher, Alice; Noël, Marie-Pascale; Pesenti, Mauro; Dormal, Valérie

    2017-09-01

    Numerous studies have tried to identify the core deficit of developmental dyscalculia (DD), mainly by assessing a possible deficit of the mental representation of numerical magnitude. Research in healthy adults has shown that numerosity, duration, and space share a partly common system of magnitude processing and representation. However, in DD, numerosity processing has until now received much more attention than the processing of other non-numerical magnitudes. To assess whether or not the processing of non-numerical magnitudes is impaired in DD, the performance of 15 adults with DD and 15 control participants was compared in four categorization tasks using numerosities, lengths, durations, and faces (as non-magnitude-based control stimuli). Results showed that adults with DD were impaired in processing numerosity and duration, while their performance in length and face categorization did not differ from controls' performance. Our findings support the idea of a nonsymbolic magnitude deficit in DD, affecting numerosity and duration processing but not length processing.

  2. Gravitation model for the magnitude of migration and its application.

    PubMed

    Zhang, T; Zhang, Z; Zhang, Q

    1997-01-01

    "The magnitude of migration is one part of the feasibility study on migration, its result being critical to the yield of positive or negative effect.... The key to the success of migration is that the magnitude of migration must be limited within the capacity of the place of destination with generous room for flexibility. It is therefore necessary to determine the appropriate magnitude by scientific methods." The geographical focus is on China. excerpt

  3. Kharkiv Asteroid Magnitude-Phase Relations V1.0

    NASA Astrophysics Data System (ADS)

    Shevchenko, V. G.; Belskaya, I. N.; Lupishko, D. F.; Krugly, Yu. N.; Chiorny, V. G.; Velichko, F. P.

    2010-08-01

    A database of asteroid magnitude-phase relations compiled at the Institute of Astronomy of Kharkiv Kharazin University by Shevchenko et al., including observations from 1978 through 2008. Mainly the observations were performed at the Institute of Astronomy (Kharkiv, Ukraine) and at the Astrophysics Institute (Dushanbe, Tadjikistan). For most asteroids the magnitude-phase relations were obtained down to phase angles less than 1 deg. For some asteroids the magnitudes are presented in three (UBV) or four (BVRI) standard spectral bands.

  4. Updating the Magnitudes of the Planets in The Astronomical Almanac

    DTIC Science & Technology

    2003-01-01

    USNO/AA Technical Note 2003-04 Updating the Magnitudes of the Planets in The Astronomical Almanac James L. Hilton The content of this Tech...the magnitudes of Mercury and Venus used in the AsA 2005 and 2006. Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden...SUBTITLE Updating The Magnitudes Of The Planets In The Astronomical Almanac 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6

  5. An empirical evolutionary magnitude estimation for earthquake early warning

    NASA Astrophysics Data System (ADS)

    Wu, Yih-Min; Chen, Da-Yi

    2016-04-01

    For earthquake early warning (EEW) system, it is a difficult mission to accurately estimate earthquake magnitude in the early nucleation stage of an earthquake occurrence because only few stations are triggered and the recorded seismic waveforms are short. One of the feasible methods to measure the size of earthquakes is to extract amplitude parameters within the initial portion of waveform after P-wave arrival. However, a large-magnitude earthquake (Mw > 7.0) may take longer time to complete the whole ruptures of the causative fault. Instead of adopting amplitude contents in fixed-length time window, that may underestimate magnitude for large-magnitude events, we suppose a fast, robust and unsaturated approach to estimate earthquake magnitudes. In this new method, the EEW system can initially give a bottom-bund magnitude in a few second time window and then update magnitude without saturation by extending the time window. Here we compared two kinds of time windows for adopting amplitudes. One is pure P-wave time widow (PTW); the other is whole-wave time window after P-wave arrival (WTW). The peak displacement amplitude in vertical component were adopted from 1- to 10-s length PTW and WTW, respectively. Linear regression analysis were implemented to find the empirical relationships between peak displacement, hypocentral distances, and magnitudes using the earthquake records from 1993 to 2012 with magnitude greater than 5.5 and focal depth less than 30 km. The result shows that using WTW to estimate magnitudes accompanies with smaller standard deviation. In addition, large uncertainties exist in the 1-second time widow. Therefore, for magnitude estimations we suggest the EEW system need to progressively adopt peak displacement amplitudes form 2- to 10-s WTW.

  6. 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

  7. 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…

  8. 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…

  9. 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…

  10. 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…

  11. 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…

  12. 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…

  13. 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…

  14. 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…

  15. 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…

  16. 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…

  17. 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…

  18. 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…

  19. 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…

  20. Rapid Earthquake Magnitude Estimation for Early Warning Applications

    NASA Astrophysics Data System (ADS)

    Goldberg, Dara; Bock, Yehuda; Melgar, Diego

    2017-04-01

    Earthquake magnitude is a concise metric that provides invaluable information about the destructive potential of a seismic event. Rapid estimation of magnitude for earthquake and tsunami early warning purposes requires reliance on near-field instrumentation. For large magnitude events, ground motions can exceed the dynamic range of near-field broadband seismic instrumentation (clipping). Strong motion accelerometers are designed with low gains to better capture strong shaking. Estimating earthquake magnitude rapidly from near-source strong-motion data requires integration of acceleration waveforms to displacement. However, integration amplifies small errors, creating unphysical drift that must be eliminated with a high pass filter. The loss of the long period information due to filtering is an impediment to magnitude estimation in real-time; the relation between ground motion measured with strong-motion instrumentation and magnitude saturates, leading to underestimation of earthquake magnitude. Using station displacements from Global Navigation Satellite System (GNSS) observations, we can supplement the high frequency information recorded by traditional seismic systems with long-period observations to better inform rapid response. Unlike seismic-only instrumentation, ground motions measured with GNSS scale with magnitude without saturation [Crowell et al., 2013; Melgar et al., 2015]. We refine the current magnitude scaling relations using peak ground displacement (PGD) by adding a large GNSS dataset of earthquakes in Japan. Because it does not suffer from saturation, GNSS alone has significant advantages over seismic-only instrumentation for rapid magnitude estimation of large events. The earthquake's magnitude can be estimated within 2-3 minutes of earthquake onset time [Melgar et al., 2013]. We demonstrate that seismogeodesy, the optimal combination of GNSS and seismic data at collocated stations, provides the added benefit of improving the sensitivity of

  1. The Effects Of Reinforcement Magnitude On Functional Analysis Outcomes

    PubMed Central

    2005-01-01

    The duration or magnitude of reinforcement has varied and often appears to have been selected arbitrarily in functional analysis research. Few studies have evaluated the effects of reinforcement magnitude on problem behavior, even though basic findings indicate that this parameter may affect response rates during functional analyses. In the current study, 6 children with autism or developmental disabilities who engaged in severe problem behavior were exposed to three separate functional analyses, each of which varied in reinforcement magnitude. Results of these functional analyses were compared to determine if a particular reinforcement magnitude was associated with the most conclusive outcomes. In most cases, the same conclusion about the functions of problem behavior was drawn regardless of the reinforcement magnitude. PMID:16033163

  2. Reinforcement magnitude: an evaluation of preference and reinforcer efficacy.

    PubMed

    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.

  3. An empirical evolutionary magnitude estimation for early warning of earthquakes

    NASA Astrophysics Data System (ADS)

    Chen, Da-Yi; Wu, Yih-Min; Chin, Tai-Lin

    2017-03-01

    The earthquake early warning (EEW) system is difficult to provide consistent magnitude estimate in the early stage of an earthquake occurrence because only few stations are triggered and few seismic signals are recorded. One of the feasible methods to measure the size of earthquakes is to extract amplitude parameters using the initial portion of the recorded waveforms after P-wave arrival. However, for a large-magnitude earthquake (Mw > 7.0), the time to complete the whole ruptures resulted from the corresponding fault may be very long. The magnitude estimations may not be correctly predicted by the initial portion of the seismograms. To estimate the magnitude of a large earthquake in real-time, the amplitude parameters should be updated with ongoing waveforms instead of adopting amplitude contents in a predefined fixed-length time window, since it may underestimate magnitude for large-magnitude events. In this paper, we propose a fast, robust and less-saturated approach to estimate earthquake magnitudes. The EEW system will initially give a lower-bound of the magnitude in a time window with a few seconds and then update magnitude with less saturation by extending the time window. Here we compared two kinds of time windows for measuring amplitudes. One is P-wave time window (PTW) after P-wave arrival; the other is whole-wave time window after P-wave arrival (WTW), which may include both P and S wave. One to ten second time windows for both PTW and WTW are considered to measure the peak ground displacement from the vertical component of the waveforms. Linear regression analysis are run at each time step (1- to 10-s time interval) to find the empirical relationships among peak ground displacement, hypocentral distances, and magnitudes using the earthquake records from 1993 to 2012 in Taiwan with magnitude greater than 5.5 and focal depth less than 30 km. The result shows that considering WTW to estimate magnitudes has smaller standard deviation than PTW. The

  4. The Instructional Dependency of SNARC Effects Reveals Flexibility of the Space-Magnitude Association of Nonsymbolic and Symbolic Magnitudes.

    PubMed

    Lee, Dasom; Chun, Joohyung; Cho, Soohyun

    2016-05-01

    The Spatial-Numerical Association of Response Codes (SNARC) effect refers to the phenomenon that small versus large numbers are responded to faster in the left versus right side of space, respectively. Using a pairwise comparison task, Shaki et al. found that task instruction influences the pattern of SNARC effects of certain types of magnitudes which are less rigid in their space-magnitude association .The present study examined the generalizability of this instruction effect using pairwise comparison of nonsymbolic and symbolic stimuli within a wide range of magnitudes. We contrasted performance between trials in which subjects were instructed to select the stimulus representing the smaller versus larger magnitude within each pair. We found an instruction-dependent pattern of SNARC effects for both nonsymbolic and symbolic magnitudes. Specifically, we observed a SNARC effect for the "Select Smaller" instruction, but a reverse SNARC effect for the "Select Larger" instruction. Considered together with previous studies, our findings suggest that nonsymbolic magnitudes and relatively large symbolic magnitudes have greater flexibility in their space-magnitude association.

  5. Adolescents with Developmental Dyscalculia Do Not Have a Generalized Magnitude Deficit – Processing of Discrete and Continuous Magnitudes

    PubMed Central

    McCaskey, Ursina; von Aster, Michael; O’Gorman Tuura, Ruth; Kucian, Karin

    2017-01-01

    The link between number and space has been discussed in the literature for some time, resulting in the theory that number, space and time might be part of a generalized magnitude system. To date, several behavioral and neuroimaging findings support the notion of a generalized magnitude system, although contradictory results showing a partial overlap or separate magnitude systems are also found. The possible existence of a generalized magnitude processing area leads to the question how individuals with developmental dyscalculia (DD), known for deficits in numerical-arithmetical abilities, process magnitudes. By means of neuropsychological tests and functional magnetic resonance imaging (fMRI) we aimed to examine the relationship between number and space in typical and atypical development. Participants were 16 adolescents with DD (14.1 years) and 14 typically developing (TD) peers (13.8 years). In the fMRI paradigm participants had to perform discrete (arrays of dots) and continuous magnitude (angles) comparisons as well as a mental rotation task. In the neuropsychological tests, adolescents with dyscalculia performed significantly worse in numerical and complex visuo-spatial tasks. However, they showed similar results to TD peers when making discrete and continuous magnitude decisions during the neuropsychological tests and the fMRI paradigm. A conjunction analysis of the fMRI data revealed commonly activated higher order visual (inferior and middle occipital gyrus) and parietal (inferior and superior parietal lobe) magnitude areas for the discrete and continuous magnitude tasks. Moreover, no differences were found when contrasting both magnitude processing conditions, favoring the possibility of a generalized magnitude system. Group comparisons further revealed that dyscalculic subjects showed increased activation in domain general regions, whilst TD peers activate domain specific areas to a greater extent. In conclusion, our results point to the existence of a

  6. Adolescents with Developmental Dyscalculia Do Not Have a Generalized Magnitude Deficit - Processing of Discrete and Continuous Magnitudes.

    PubMed

    McCaskey, Ursina; von Aster, Michael; O'Gorman Tuura, Ruth; Kucian, Karin

    2017-01-01

    The link between number and space has been discussed in the literature for some time, resulting in the theory that number, space and time might be part of a generalized magnitude system. To date, several behavioral and neuroimaging findings support the notion of a generalized magnitude system, although contradictory results showing a partial overlap or separate magnitude systems are also found. The possible existence of a generalized magnitude processing area leads to the question how individuals with developmental dyscalculia (DD), known for deficits in numerical-arithmetical abilities, process magnitudes. By means of neuropsychological tests and functional magnetic resonance imaging (fMRI) we aimed to examine the relationship between number and space in typical and atypical development. Participants were 16 adolescents with DD (14.1 years) and 14 typically developing (TD) peers (13.8 years). In the fMRI paradigm participants had to perform discrete (arrays of dots) and continuous magnitude (angles) comparisons as well as a mental rotation task. In the neuropsychological tests, adolescents with dyscalculia performed significantly worse in numerical and complex visuo-spatial tasks. However, they showed similar results to TD peers when making discrete and continuous magnitude decisions during the neuropsychological tests and the fMRI paradigm. A conjunction analysis of the fMRI data revealed commonly activated higher order visual (inferior and middle occipital gyrus) and parietal (inferior and superior parietal lobe) magnitude areas for the discrete and continuous magnitude tasks. Moreover, no differences were found when contrasting both magnitude processing conditions, favoring the possibility of a generalized magnitude system. Group comparisons further revealed that dyscalculic subjects showed increased activation in domain general regions, whilst TD peers activate domain specific areas to a greater extent. In conclusion, our results point to the existence of a

  7. 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.

  8. 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.

  9. Does residual force enhancement increase with increasing stretch magnitudes?

    PubMed

    Hisey, Brandon; Leonard, Tim R; Herzog, Walter

    2009-07-22

    It is generally accepted that force enhancement in skeletal muscles increases with increasing stretch magnitudes. However, this property has not been tested across supra-physiological stretch magnitudes and different muscle lengths, thus it is not known whether this is a generic property of skeletal muscle, or merely a property that holds for small stretch magnitudes within the physiological range. Six cat soleus muscles were actively stretched with magnitudes varying from 3 to 24 mm at three different parts of the force-length relationship to test the hypothesis that force enhancement increases with increasing stretch magnitude, independent of muscle length. Residual force enhancement increased consistently with stretch amplitudes on the descending limb of the force-length relationship up to a threshold value, after which it reached a plateau. Force enhancement did not increase with stretch amplitude on the ascending limb of the force-length relationship. Passive force enhancement was observed for all test conditions, and paralleled the behavior of the residual force enhancement. Force enhancement increased with stretch magnitude when stretching occurred at lengths where there was natural passive force within the muscle. These results suggest that force enhancement does not increase unconditionally with increasing stretch magnitude, as is generally accepted, and that increasing force enhancement with stretch appears to be tightly linked to that part of the force-length relationship where there is naturally occurring passive force.

  10. Multiscale mapping of completeness magnitude of earthquake catalogs

    NASA Astrophysics Data System (ADS)

    Vorobieva, Inessa; Narteau, Clement; Shebalin, Peter; Beauducel, François; Nercessian, Alexandre; Clouard, Valérie; Bouin, Marie-Paule

    2013-04-01

    We propose a multiscale method to map spatial variations in completeness magnitude Mc of earthquake catalogs. The Mc value may significantly vary in space due to the change of the seismic network density. Here we suggest a way to use only earthquake catalogs to separate small areas of higher network density (lower Mc) and larger areas of smaller network density (higher Mc). We reduce the analysis of the FMDs to the limited magnitude ranges, thus allowing deviation of the FMD from the log-linearity outside the range. We associate ranges of larger magnitudes with increasing areas for data selection based on constant in average number of completely recorded earthquakes. Then, for each point in space, we document the earthquake frequency-magnitude distribution at all length scales within the corresponding earthquake magnitude ranges. High resolution of the Mc-value is achieved through the determination of the smallest space-magnitude scale in which the Gutenberg-Richter law (i. e. an exponential decay) is verified. The multiscale procedure isolates the magnitude range that meets the best local seismicity and local record capacity. Using artificial catalogs and earthquake catalogs of the Lesser Antilles arc, this Mc mapping method is shown to be efficient in regions with mixed types of seismicity, a variable density of epicenters and various levels of registration.

  11. 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.

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

    USGS Publications Warehouse

    Van Der Elst, Nicholas; Page, Morgan T.; Weiser, Deborah A.; Goebel, Thomas; Hosseini, S. Mehran

    2016-01-01

    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.

  13. 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.

  14. 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.

  15. Defining Tsunami Magnitude as Measure of Potential Impact

    NASA Astrophysics Data System (ADS)

    Titov, V. V.; Tang, L.

    2016-12-01

    The goal of tsunami forecast, as a system for predicting potential impact of a tsunami at coastlines, requires quick estimate of a tsunami magnitude. This goal has been recognized since the beginning of tsunami research. The work of Kajiura, Soloviev, Abe, Murty, and many others discussed several scales for tsunami magnitude based on estimates of tsunami energy. However, difficulties of estimating tsunami energy based on available tsunami measurements at coastal sea-level stations has carried significant uncertainties and has been virtually impossible in real time, before tsunami impacts coastlines. The slow process of tsunami magnitude estimates, including collection of vast amount of available coastal sea-level data from affected coastlines, made it impractical to use any tsunami magnitude scales in tsunami warning operations. Uncertainties of estimates made tsunami magnitudes difficult to use as universal scale for tsunami analysis. Historically, the earthquake magnitude has been used as a proxy of tsunami impact estimates, since real-time seismic data is available of real-time processing and ample amount of seismic data is available for an elaborate post event analysis. This measure of tsunami impact carries significant uncertainties in quantitative tsunami impact estimates, since the relation between the earthquake and generated tsunami energy varies from case to case. In this work, we argue that current tsunami measurement capabilities and real-time modeling tools allow for establishing robust tsunami magnitude that will be useful for tsunami warning as a quick estimate for tsunami impact and for post-event analysis as a universal scale for tsunamis inter-comparison. We present a method for estimating the tsunami magnitude based on tsunami energy and present application of the magnitude analysis for several historical events for inter-comparison with existing methods.

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

    PubMed

    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 [Formula: see text] 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 [Formula: see text] probe designs as functions of frequency and field magnitude are presented. The first [Formula: see text] 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% [Formula: see text] 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% [Formula: see text] 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

  17. 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

  18. 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

  19. 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.

  20. Numerical and physical magnitudes are mapped into time.

    PubMed

    Ben-Meir, Shachar; Ganor-Stern, Dana; Tzelgov, Joseph

    2012-01-01

    In two experiments we investigated mapping of numerical and physical magnitudes with temporal order. Pairs of digits were presented sequentially for a size comparison task. An advantage for numbers presented in ascending order was found when participants were comparing the numbers' physical and numerical magnitudes. The effect was more robust for comparisons of physical size, as it was found using both select larger and select smaller instructions, while for numerical comparisons it was found only for select larger instructions. Varying both the digits' numerical and physical sizes resulted in a size congruity effect, indicating automatic processing of the irrelevant magnitude dimension. Temporal order and the congruency between numerical and physical magnitudes affected comparisons in an additive manner, thus suggesting that they affect different stages of the comparison process.

  1. Operative mechanisms of noncontingent reinforcement at varying magnitudes and schedules.

    PubMed

    Wilder, D A; Fisher, W W; Anders, B M; Cercone, J J; Neidert, P L

    2001-01-01

    In order to examine the mechanism(s) responsible for response reductions from noncontingent reinforcement (NCR), multiple magnitudes and densities of NCR were superimposed on a variable ratio (VR) 3 schedule of contingent reinforcement for the performance of an arbitrary manual response. Data were collected on responding that occurred during access to the reinforcer separately from responding that occurred between reinforcer access intervals (i.e.. when the participant did not have access to the reinforcer). Higher magnitudes and denser schedules of NCR produced greater reductions in responding than did lower magnitudes and leaner schedules. Within-session response patterns suggested that decrements in responding were primarily a function of the increased amount of reinforcer access time associated with higher magnitudes and denser schedules of NCR. That is, it appeared that the participant consumed reinforcers (regardless of whether they were delivered contingently or noncontingently) when they were available and responded for contingent reinforcers primarily when reinforcers were absent.

  2. 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.

  3. Number games, magnitude representation, and basic number skills in preschoolers.

    PubMed

    Whyte, Jemma Catherine; Bull, Rebecca

    2008-03-01

    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 compared following four 25-min intervention sessions. The linear number board game significantly improved children's performance in all posttest measures and facilitated a shift from a logarithmic to a linear representation of numerical magnitude, emphasizing the importance of spatial cues in estimation. Exposure to the number card games involving nonsymbolic magnitude judgments and association of symbolic and nonsymbolic quantities, but without any linear spatial cues, improved some aspects of children's basic number skills but not numerical estimation precision.

  4. 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)

  5. I love my baffling, backward, counterintuitive, overly complicated magnitudes

    NASA Astrophysics Data System (ADS)

    Sirola, Christopher

    2017-02-01

    All professions have their jargon. But astronomy goes the extra parsec. Here's an example. Vega, one of the brighter stars in the night sky, has an apparent magnitude (i.e., an apparent brightness) of approximately zero. Polaris, the North Star, has an apparent magnitude of about +2. Despite this, Vega appears brighter than Polaris, and not by two, but by a factor of about six times.

  6. The Color-Magnitude Distribution of Small Jupiter Trojans

    NASA Astrophysics Data System (ADS)

    Wong, Ian; Brown, Michael E.

    2015-12-01

    We present an analysis of survey observations targeting the leading L4 Jupiter Trojan cloud near opposition using the wide-field Suprime-Cam CCD camera on the 8.2 m Subaru Telescope. The survey covered about 38 deg2 of sky and imaged 147 fields spread across a wide region of the L4 cloud. Each field was imaged in both the g‧ and the i‧ band, allowing for the measurement of g - i color. We detected 557 Trojans in the observed fields, ranging in absolute magnitude from H = 10.0 to H = 20.3. We fit the total magnitude distribution to a broken power law and show that the power-law slope rolls over from 0.45 ± 0.05 to {0.36}-0.09+0.05 at a break magnitude of {H}b={14.93}-0.88+0.73. Combining the best-fit magnitude distribution of faint objects from our survey with an analysis of the magnitude distribution of bright objects listed in the Minor Planet Center catalog, we obtain the absolute magnitude distribution of Trojans over the entire range from H = 7.2 to H = 16.4. We show that the g - i color of Trojans decreases with increasing magnitude. In the context of the less-red and red color populations, as classified in Wong et al. using photometric and spectroscopic data, we demonstrate that the observed trend in color for the faint Trojans is consistent with the expected trend derived from extrapolation of the best-fit color population magnitude distributions for bright cataloged Trojans. This indicates a steady increase in the relative number of less-red objects with decreasing size. Finally, we interpret our results using collisional modeling and propose several hypotheses for the color evolution of the Jupiter Trojan population. Based on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.

  7. Magnitude and distribution pattern of zinc in oysters

    SciTech Connect

    Koki, A.K.; Whitmore, R.; Lester, L.C. Jr.

    1986-06-01

    This study was an attempt to assess the magnitude and distribution pattern of trace element zinc in oysters to see if the problem of the magnitude of zinc contamination was evident in the South Carolina Fishery. It would identify potentially hazardous situations and persons affected would be made aware of the problem. Where high zinc concentration are found in oysters, it would then attempt to identify the source of pollution.

  8. The magnitude of innovation and its evolution in social animals.

    PubMed

    Arbilly, Michal; Laland, Kevin N

    2017-02-08

    Innovative behaviour in animals, ranging from invertebrates to humans, is increasingly recognized as an important topic for investigation by behavioural researchers. However, what constitutes an innovation remains controversial, and difficult to quantify. Drawing on a broad definition whereby any behaviour with a new component to it is an innovation, we propose a quantitative measure, which we call the magnitude of innovation, to describe the extent to which an innovative behaviour is novel. This allows us to distinguish between innovations that are a slight change to existing behaviours (low magnitude), and innovations that are substantially different (high magnitude). Using mathematical modelling and evolutionary computer simulations, we explored how aspects of social interaction, cognition and natural selection affect the frequency and magnitude of innovation. We show that high-magnitude innovations are likely to arise regularly even if the frequency of innovation is low, as long as this frequency is relatively constant, and that the selectivity of social learning and the existence of social rewards, such as prestige and royalties, are crucial for innovative behaviour to evolve. We suggest that consideration of the magnitude of innovation may prove a useful tool in the study of the evolution of cognition and of culture.

  9. 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.

  10. 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.

  11. 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.

  12. Loudness counts: Interactions between loudness, number magnitude, and space.

    PubMed

    Hartmann, Matthias; Mast, Fred W

    2017-07-01

    ATOM (a theory of magnitude) suggests that magnitude information of different formats (numbers, space, and time) is processed within a generalized magnitude network. In this study we investigated whether loudness, as a possible indicator of intensity and magnitude, interacts with the processing of numbers. Small and large numbers, spoken in a quiet and a loud voice, were simultaneously presented to the left and right ear (Experiments 1a and 1b). Participants judged whether the number presented to the left or right ear was louder or larger. Responses were faster when the smaller number was spoken in a quiet voice, and the larger number in a loud voice. Thus, task-irrelevant numerical information influenced the processing of loudness and vice versa. This bi-directional link was also confirmed by classical SNARC paradigms (spatial-numerical association of response codes; Experiments 2a-2c) when participants again judged the magnitude or loudness of separately presented stimuli. In contrast, no loudness-number association was found in a parity judgment task. Regular SNARC effects were found in the magnitude and parity judgment task, but not in the loudness judgment task. Instead, in the latter task, response side was associated with loudness. Possible explanations for these results are discussed.

  13. A probabilistic neural network for earthquake magnitude prediction.

    PubMed

    Adeli, Hojjat; Panakkat, Ashif

    2009-09-01

    A probabilistic neural network (PNN) is presented for predicting the magnitude of the largest earthquake in a pre-defined future time period in a seismic region using eight mathematically computed parameters known as seismicity indicators. The indicators considered are the time elapsed during a particular number (n) of significant seismic events before the month in question, the slope of the Gutenberg-Richter inverse power law curve for the n events, the mean square deviation about the regression line based on the Gutenberg-Richter inverse power law for the n events, the average magnitude of the last n events, the difference between the observed maximum magnitude among the last n events and that expected through the Gutenberg-Richter relationship known as the magnitude deficit, the rate of square root of seismic energy released during the n events, the mean time or period between characteristic events, and the coefficient of variation of the mean time. Prediction accuracies of the model are evaluated using three different statistical measures: the probability of detection, the false alarm ratio, and the true skill score or R score. The PNN model is trained and tested using data for the Southern California region. The model yields good prediction accuracies for earthquakes of magnitude between 4.5 and 6.0. The PNN model presented in this paper complements the recurrent neural network model developed by the authors previously, where good results were reported for predicting earthquakes with magnitude greater than 6.0.

  14. Estimation of the magnitudes and epicenters of Philippine historical earthquakes

    NASA Astrophysics Data System (ADS)

    Bautista, Maria Leonila P.; Oike, Kazuo

    2000-02-01

    The magnitudes and epicenters of Philippine earthquakes from 1589 to 1895 are estimated based on the review, evaluation and interpretation of historical accounts and descriptions. The first step involves the determination of magnitude-felt area relations for the Philippines for use in the magnitude estimation. Data used were the earthquake reports of 86, recent, shallow events with well-described effects and known magnitude values. Intensities are assigned according to the modified Mercalli intensity scale of I to XII. The areas enclosed by Intensities III to IX [ A(III) to A(IX)] are measured and related to magnitude values. The most robust relations are found for magnitudes relating to A(VI), A(VII), A(VIII) and A(IX). Historical earthquake data are obtained from primary sources in libraries in the Philippines and Spain. Most of these accounts were made by Spanish priests and officials stationed in the Philippines during the 15th to 19th centuries. More than 3000 events are catalogued, interpreted and their intensities determined by considering the possible effects of local site conditions, type of construction and the number and locations of existing towns to assess completeness of reporting. Of these events, 485 earthquakes with the largest number of accounts or with at least a minimum report of damage are selected. The historical epicenters are estimated based on the resulting generalized isoseismal maps augmented by information on recent seismicity and location of known tectonic structures. Their magnitudes are estimated by using the previously determined magnitude-felt area equations for recent events. Although historical epicenters are mostly found to lie on known tectonic structures, a few, however, are found to lie along structures that show not much activity during the instrumented period. A comparison of the magnitude distributions of historical and recent events showed that only the period 1850 to 1900 may be considered well-reported in terms of

  15. Probable Maximum Earthquake Magnitudes for the Cascadia Subduction

    NASA Astrophysics Data System (ADS)

    Rong, Y.; Jackson, D. D.; Magistrale, H.; Goldfinger, C.

    2013-12-01

    The concept of maximum earthquake magnitude (mx) is widely used in seismic hazard and risk analysis. However, absolute mx lacks a precise definition and cannot be determined from a finite earthquake history. The surprising magnitudes of the 2004 Sumatra and the 2011 Tohoku earthquakes showed that most methods for estimating mx underestimate the true maximum if it exists. Thus, we introduced the alternate concept of mp(T), probable maximum magnitude within a time interval T. The mp(T) can be solved using theoretical magnitude-frequency distributions such as Tapered Gutenberg-Richter (TGR) distribution. The two TGR parameters, β-value (which equals 2/3 b-value in the GR distribution) and corner magnitude (mc), can be obtained by applying maximum likelihood method to earthquake catalogs with additional constraint from tectonic moment rate. Here, we integrate the paleoseismic data in the Cascadia subduction zone to estimate mp. The Cascadia subduction zone has been seismically quiescent since at least 1900. Fortunately, turbidite studies have unearthed a 10,000 year record of great earthquakes along the subduction zone. We thoroughly investigate the earthquake magnitude-frequency distribution of the region by combining instrumental and paleoseismic data, and using the tectonic moment rate information. To use the paleoseismic data, we first estimate event magnitudes, which we achieve by using the time interval between events, rupture extent of the events, and turbidite thickness. We estimate three sets of TGR parameters: for the first two sets, we consider a geographically large Cascadia region that includes the subduction zone, and the Explorer, Juan de Fuca, and Gorda plates; for the third set, we consider a narrow geographic region straddling the subduction zone. In the first set, the β-value is derived using the GCMT catalog. In the second and third sets, the β-value is derived using both the GCMT and paleoseismic data. Next, we calculate the corresponding mc

  16. 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.

  17. Problemas de nervos: a multivocal symbol of distress for Portuguese immigrants.

    PubMed

    James, Susan; Fernandes, Mark; Navara, Geoffrey S; Harris, Sara; Foster, Durwin

    2009-06-01

    This article outlines research on a previous unstudied form of suffering specific to the Portugese immigrant community: problemas de nervos. Thirty-two Portuguese immigrant women (in Waterloo, ON and Boston, MA) were interviewed and each completed a questionnaire. Cluster analysis demonstrated that problemas de nervos has many meanings. The study profiled symptoms, causes and therapies associated with four variations of this culture-specific form of distress: "mal da cabeca" meaning problems with/in the head (e.g., lack of control, visions); " aflição" meaning affliction (e.g., nervous attacks, heart problems); immigration stress (causing sleep disturbances); and, conflicts with others (resulting in pressure within the body). None of the symptom clusters reported matched criteria for a DSM-IV-TR diagnosis, suggesting that problemas de nervos represents an idiomatic rather than universal expression of distress.

  18. Towards Reconciling Magnitude-Invariant Stress Drops with Dynamic Weakening

    NASA Astrophysics Data System (ADS)

    Perry, S. M.; Lapusta, N.

    2014-12-01

    The energy budget of earthquakes is a question of significant fundamental and practical interest. Using rate-and-state fault models that produce earthquake sequences, we focus on exploring the breakdown energy portion G of this budget and its relation to stress drop in events over a range of magnitudes. We focus on understanding which models can reproduce the observation that breakdown energy increases with increasing magnitude, but stress drop appears to be magnitude-invariant. We begin with simulations with pure rate-and-state friction and study how breakdown energy changes with characteristic slip distance L of rate-and-state friction, a parameter often selected based on numerical tractability. We explore values of L ranging two orders of magnitude and calculate breakdown energy G for events with various amounts of slip. The values of G in our simulations are similar to those of natural earthquakes. However, we find nearly-constant values of G across a range of slips for a given L, as well as decreasing G with smaller values of L, as expected based on prior studies. Hence simulations with laboratory-like values of L (0.01-0.1 mm), necessary for producing microseismicity, would result in breakdown energies too small for large events, compared with observations. We then proceed to a model utilizing dynamic weakening due to thermal pressurization of pore fluid within the fault core. Co-seismic weakening through mechanisms such as thermal pressurization can explain the trend of increasing breakdown energy with magnitude as shown by Rice (JGR, 2006) in a simplified slip model. Our goal is to explore this result in fully dynamic simulations that produce a series of seismic events of different sizes, and investigate whether it can be reconciled with the magnitude-invariant stress drop. We find that our sequences are able to capture the trend of increasing breakdown energy with increasing magnitude while also displaying roughly magnitude-invariant stress drops for a

  19. 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

  20. 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

  1. Magnitude and phase behavior of multiresolution BOLD signal

    PubMed Central

    Chen, Zikuan; Calhoun, Vince D.

    2010-01-01

    High spatial resolution fMRI provides a more precise estimate of brain activity than low resolution fMRI. The magnitude and phase parts of the BOLD signals are impacted differently by changes in the scan resolution. In this paper, we report on a numerical simulation to show the impact of spatial resolution upon the complex-valued BOLD signal in terms of magnitude and phase variation. We generate realistic capillary networks in cortex voxels, calculate the BOLD-induced magnetic field disturbance and the complex BOLD signals for the voxel and its subvoxels, and thereby characterize the magnitude and phase behaviors across multiple grid resolutions. Our results show that: 1) at higher spatial resolution there is greater spatial variation in the phase of the BOLD signal as compared to its magnitude; 2) the spatial variation of the phase signal monotonically increases with respect to spatial resolution while for the magnitude the spatial variation may reach a maximum at some resolution level; 3) voxels containing large capillaries have higher phase spatial variation than those with smaller capillaries; 4) the amplitude spatial variation at a resolution level increases with respect to relaxation time whereas the phase variation is generally unaffected. PMID:20890375

  2. Modeling of magnitude distributions by the generalized truncated exponential distribution

    NASA Astrophysics Data System (ADS)

    Raschke, Mathias

    2015-01-01

    The probability distribution of the magnitude can be modeled by an exponential distribution according to the Gutenberg-Richter relation. Two alternatives are the truncated exponential distribution (TED) and the cutoff exponential distribution (CED). The TED is frequently used in seismic hazard analysis although it has a weak point: when two TEDs with equal parameters except the upper bound magnitude are mixed, then the resulting distribution is not a TED. Inversely, it is also not possible to split a TED of a seismic region into TEDs of subregions with equal parameters except the upper bound magnitude. This weakness is a principal problem as seismic regions are constructed scientific objects and not natural units. We overcome it by the generalization of the abovementioned exponential distributions: the generalized truncated exponential distribution (GTED). Therein, identical exponential distributions are mixed by the probability distribution of the correct cutoff points. This distribution model is flexible in the vicinity of the upper bound magnitude and is equal to the exponential distribution for smaller magnitudes. Additionally, the exponential distributions TED and CED are special cases of the GTED. We discuss the possible ways of estimating its parameters and introduce the normalized spacing for this purpose. Furthermore, we present methods for geographic aggregation and differentiation of the GTED and demonstrate the potential and universality of our simple approach by applying it to empirical data. The considerable improvement by the GTED in contrast to the TED is indicated by a large difference between the corresponding values of the Akaike information criterion.

  3. Separate Magnitude and Phase Regularization via Compressed Sensing

    PubMed Central

    Noll, Douglas C.; Nielsen, Jon-Fredrik; Fessler, Jeffrey A.

    2012-01-01

    Compressed sensing (CS) has been used for accelerating magnetic resonance imaging (MRI) acquisitions, but its use in applications with rapid spatial phase variations is challenging, e.g., proton resonance frequency shift (PRF-shift) thermometry and velocity mapping. Previously, an iterative MRI reconstruction with separate magnitude and phase regularization was proposed for applications where magnitude and phase maps are both of interest, but it requires fully sampled data and unwrapped phase maps. In this paper, CS is combined into this framework to reconstruct magnitude and phase images accurately from undersampled data. Moreover, new phase regularization terms are proposed to accommodate phase wrapping and to reconstruct images with encoded phase variations, e.g., PRF-shift thermometry and velocity mapping. The proposed method is demonstrated with simulated thermometry data and in-vivo velocity mapping data and compared to conventional phase corrected CS. PMID:22552571

  4. Magnitude and Frequency of Floods in Alabama, 2003

    USGS Publications Warehouse

    Hedgecock, T.S.; Feaster, Toby D.

    2007-01-01

    Methods of estimating flood magnitudes for recurrence intervals of 1.5, 2, 5, 10, 25, 50, 100, 200, and 500 years have been developed for rural streams in Alabama that are not affected by regulation or urbanization. Regression relations were developed using generalized least-squares regression techniques to estimate flood magnitude and frequency on ungaged streams as a function of the basin drainage area. These methods are based on flood-frequency characteristics for 169 gaging stations in Alabama and 47 gaging stations in adjacent states having 10 or more years of record through September 2003. Graphical relations of peak flows to drainage areas are presented for sites along the Alabama, Coosa, Tallapoosa, Tennessee, Tombigbee, and Black Warrior Rivers. Equations that account for drainage area and percentage of impervious cover as independent variables also are provided for estimating flood magnitudes on ungaged urban streams (taken from a previous report).

  5. Task difficulty in mental arithmetic affects microsaccadic rates and magnitudes.

    PubMed

    Siegenthaler, Eva; Costela, Francisco M; McCamy, Michael B; Di Stasi, Leandro L; Otero-Millan, Jorge; Sonderegger, Andreas; Groner, Rudolf; Macknik, Stephen; Martinez-Conde, Susana

    2014-01-01

    Microsaccades are involuntary, small-magnitude saccadic eye movements that occur during attempted visual fixation. Recent research has found that attention can modulate microsaccade dynamics, but few studies have addressed the effects of task difficulty on microsaccade parameters, and those have obtained contradictory results. Further, no study to date has investigated the influence of task difficulty on microsaccade production during the performance of non-visual tasks. Thus, the effects of task difficulty on microsaccades, isolated from sensory modality, remain unclear. Here we investigated the effects of task difficulty on microsaccades during the performance of a non-visual, mental arithmetic task with two levels of complexity. We found that microsaccade rates decreased and microsaccade magnitudes increased with increased task difficulty. We propose that changes in microsaccade rates and magnitudes with task difficulty are mediated by the effects of varying attentional inputs on the rostral superior colliculus activity map.

  6. Executive function and magnitude skills in preschool children.

    PubMed

    Prager, Emily O; Sera, Maria D; Carlson, Stephanie M

    2016-07-01

    Executive function (EF) has been highlighted as a potentially important factor for mathematical understanding. The relation has been well established in school-aged children but has been less explored at younger ages. The current study investigated the relation between EF and mathematics in preschool-aged children. Participants were 142 typically developing 3- and 4-year-olds. Controlling for verbal ability, a significant positive correlation was found between EF and general math abilities in this age group. Importantly, we further examined this relation causally by varying the EF load on a magnitude comparison task. Results suggested a developmental pattern where 3-year-olds' performance on the magnitude comparison task was worst when EF was taxed the most. Conversely, 4-year-olds performed well on the magnitude task despite varying EF demands, suggesting that EF might play a critical role in the development of math concepts.

  7. 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.

  8. 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

  9. 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. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  10. 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

  11. 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.

  12. Calibration of magnitude scales for earthquakes of the Mediterranean

    NASA Astrophysics Data System (ADS)

    Gardini, Domenico; di Donato, Maria; Boschi, Enzo

    In order to provide the tools for uniform size determination for Mediterranean earthquakes over the last 50-year period of instrumental seismology, we have regressed the magnitude determinations for 220 earthquakes of the European-Mediterranean region over the 1977-1991 period, reported by three international centres, 11 national and regional networks and 101 individual stations and observatories, using seismic moments from the Harvard CMTs. We calibrate M(M0) regression curves for the magnitude scales commonly used for Mediterranean earthquakes (ML, MWA, mb, MS, MLH, MLV, MD, M); we also calibrate static corrections or specific regressions for individual observatories and we verify the reliability of the reports of different organizations and observatories. Our analysis shows that the teleseismic magnitudes (mb, MS) computed by international centers (ISC, NEIC) provide good measures of earthquake size, with low standard deviations (0.17-0.23), allowing one to regress stable regional calibrations with respect to the seismic moment and to correct systematic biases such as the hypocentral depth for MS and the radiation pattern for mb; while mb is commonly reputed to be an inadequate measure of earthquake size, we find that the ISC mb is still today the most precise measure to use to regress MW and M0 for earthquakes of the European-Mediterranean region; few individual observatories report teleseismic magnitudes requiring specific dynamic calibrations (BJI, MOS). Regional surface-wave magnitudes (MLV, MLH) reported in Eastern Europe generally provide reliable measures of earthquake size, with standard deviations often in the 0.25-0.35 range; the introduction of a small (±0.1-0.2) static station correction is sometimes required. While the Richter magnitude ML is the measure of earthquake size most commonly reported in the press whenever an earthquake strikes, we find that ML has not been computed in the European-Mediterranean in the last 15 years; the reported local

  13. 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

  14. 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…

  15. 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.

  16. 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…

  17. The Magnitude Distribution of Earthquakes Near Southern California Faults

    DTIC Science & Technology

    2011-12-16

    Lindh , 1985; Jackson and Kagan, 2006]. We do not consider time dependence in this study, but focus instead on the magnitude distribution for this fault...90032-7. Bakun, W. H., and A. G. Lindh (1985), The Parkfield, California, earth- quake prediction experiment, Science, 229(4714), 619–624, doi:10.1126

  18. Connecting the Points: Cognitive Conflict and Decimal Magnitude

    ERIC Educational Resources Information Center

    Moody, Bruce

    2010-01-01

    This paper reports on an investigation into managing cognitive conflict in the context of student learning about decimal magnitude. The influence of prior constructs is examined through a brief review of the literature. A micro-genetic approach was used to capture detail of the teaching intervention used to facilitate development in student…

  19. 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…

  20. A Strategy to Rapidly Determine the Magnitude of Great Earthquakes

    NASA Astrophysics Data System (ADS)

    Menke, William; Levin, Vadim

    2005-05-01

    In the initial hours following the origin of the Sumatra-Andaman Islands earthquake at 0058:53 GMT on 26 December 2004, the event was widely reported as having a magnitude of about 8. Thus, its potential for generating a damaging teletsunami (ocean-crossing tsunami) was considered minimal. The event's size later was shown to be approximately 10 times larger, but only after more than four and a half hours had passed, when a moment estimate based on 2.5 hours of data became available from Harvard University's Centroid-Moment Tensor (CMT) Project (M. Nettles and G. Ekstrom, Quick CMT of the 2004 Sumatra-Andaman Islands earthquake, Seismoware FID: BR345, e-mailed announcement, 26 December 2004). This estimate placed its magnitude at Mw ~ 9.0, in the range capable of generating a damaging teletsunami. Actually, the earthquake had caused a teletsunami, one that by that time had already killed more than a hundred thousand people. The magnitude estimate has been subsequently revised to at least 9.3 (Stein and Okal, http://www.earth.northwestern.edu/people/~seth/research/sumatra.html), with the exact magnitude of the event likely to be a subject of further research in the coming years.

  1. 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…

  2. 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…

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

    PubMed

    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.

  5. 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.

  6. On generating and derived magnitudes of stellar magnetic fields

    NASA Astrophysics Data System (ADS)

    Gerth, E.; Glagolevskij, Yu. V.

    2004-10-01

    The structure of the stellar surface magnetic field is covered from direct observation by many mixing processes. The discovery of the topographic surface structure requires an inversion procedure but does not reveal the origin of the magnetic field. Modelling of magnetic stars, however, has to start from the generating magnitudes and is a matter of construction by a strategy of forward calculation. The model of the star is fitted to the observed appearance of the real object by variation of parameters and optimizing. The magnetic field strength on the surface of the star -- including the magnetic poles -- is a derived magnitude, which should not be taken as a parameter for modeling. At the present time two versions of magnetic modeling are discussed: 1) expansion of spherical harmonics, 2) magnetic charge distribution. Both methods claim for the application of parameters, which determine the magnetic field. In this paper the question is investigated, what the generating and the derived magnitudes of the magnetic field are. Tracing back the observed spherical distribution of the magnetic field to its origin, one is led to the eigen values as the solution of Legendre's differential equation. We regard the eigen values as the generating magnitudes of the magnetic field, the physical quantities of which are the constituents of any vector field, namely the sources and vortices, from which the field originates. This interpretation is substantiated by graphical representations of magnetic maps with topographical features like poles -- derived from the field-generating sources: the virtual magnetic charges.

  7. 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…

  8. 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…

  9. 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…

  10. 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…

  11. Magnitude Dependent Seismic Quiescence of 2008 Wenchuan Earthquake

    NASA Astrophysics Data System (ADS)

    Suyehiro, K.; Sacks, S. I.; Takanami, T.; Smith, D. E.; Rydelek, P. A.

    2014-12-01

    The change in seismicity leading to the Wenchuan Earthquake in 2008 (Mw 7.9) has been studied by various authors based on statistics and/or pattern recognitions (Huang, 2008; Yan et al., 2009; Chen and Wang, 2010; Yi et al., 2011). We show, in particular, that the magnitude-dependent seismic quiescence is observed for the Wenchuan earthquake and that it adds to other similar observations. Such studies on seismic quiescence prior to major earthquakes include 1982 Urakawa-Oki earthquake (M 7.1) (Taylor et al., 1992), 1994 Hokkaido-Toho-Oki earthquake (Mw=8.2) (Takanami et al., 1996), 2011 Tohoku earthquake (Mw=9.0) (Katsumata, 2011). Smith and Sacks (2013) proposed a magnitude-dependent quiescence based on a physical earthquake model (Rydelek and Sacks, 1995) and demonstrated the quiescence can be reproduced by the introduction of "asperities" (dilantacy hardened zones). Actual observations indicate the change occurs in a broader area than the eventual earthquake fault zone. In order to accept the explanation, we need to verify the model as the model predicts somewhat controversial features of earthquakes such as the magnitude dependent stress drop at lower magnitude range or the dynamically appearing asperities and repeating slips in some parts of the rupture zone. We show supportive observations. We will also need to verify the dilatancy diffusion to be taking place. So far, we only seem to have indirect evidences, which need to be more quantitatively substantiated.

  12. 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…

  13. 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…

  14. Common magnitude representation of fractions and decimals is task dependent.

    PubMed

    Zhang, Li; Fang, Qiaochu; Gabriel, Florence C; Szűcs, Denes

    2016-01-01

    Although several studies have compared the representation of fractions and decimals, no study has investigated whether fractions and decimals, as two types of rational numbers, share a common representation of magnitude. The current study aimed to answer the question of whether fractions and decimals share a common representation of magnitude and whether the answer is influenced by task paradigms. We included two different number pairs, which were presented sequentially: fraction-decimal mixed pairs and decimal-fraction mixed pairs in all four experiments. Results showed that when the mixed pairs were very close numerically with the distance 0.1 or 0.3, there was a significant distance effect in the comparison task but not in the matching task. However, when the mixed pairs were further apart numerically with the distance 0.3 or 1.3, the distance effect appeared in the matching task regardless of the specific stimuli. We conclude that magnitudes of fractions and decimals can be represented in a common manner, but how they are represented is dependent on the given task. Fractions and decimals could be translated into a common representation of magnitude in the numerical comparison task. In the numerical matching task, fractions and decimals also shared a common representation. However, both of them were represented coarsely, leading to a weak distance effect. Specifically, fractions and decimals produced a significant distance effect only when the numerical distance was larger.

  15. Magnitude, precision, and realism of depth perception in stereoscopic vision.

    PubMed

    Hibbard, Paul B; Haines, Alice E; Hornsey, Rebecca L

    2017-01-01

    Our perception of depth is substantially enhanced by the fact that we have binocular vision. This provides us with more precise and accurate estimates of depth and an improved qualitative appreciation of the three-dimensional (3D) shapes and positions of objects. We assessed the link between these quantitative and qualitative aspects of 3D vision. Specifically, we wished to determine whether the realism of apparent depth from binocular cues is associated with the magnitude or precision of perceived depth and the degree of binocular fusion. We presented participants with stereograms containing randomly positioned circles and measured how the magnitude, realism, and precision of depth perception varied with the size of the disparities presented. We found that as the size of the disparity increased, the magnitude of perceived depth increased, while the precision with which observers could make depth discrimination judgments decreased. Beyond an initial increase, depth realism decreased with increasing disparity magnitude. This decrease occurred well below the disparity limit required to ensure comfortable viewing.

  16. 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

  17. 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

  18. Earthquake Early Warning with Seismogeodesy: Detection, Location, and Magnitude Estimation

    NASA Astrophysics Data System (ADS)

    Goldberg, D.; Bock, Y.; Melgar, D.

    2016-12-01

    Earthquake early warning is critical to reducing injuries and casualties in case of a large magnitude earthquake. The system must rely on near-source data to minimize the time between event onset and issuance of a warning. Early warning systems typically use seismic instruments (seismometers and accelerometers), but these instruments experience difficulty maintaining reliable data in the near-source region and undergo magnitude saturation for large events. Global Navigation Satellite System (GNSS) instruments capture the long period motions and have been shown to produce robust estimates of the true size of the earthquake source. However, GNSS is often overlooked in this context in part because it is not precise enough to record the first seismic wave arrivals (P-wave detection), an important consideration for issuing an early warning. GNSS instruments are becoming integrated into early warning, but are not yet fully exploited. Our approach involves the combination of direct measurements from collocated GNSS and accelerometer stations to estimate broadband coseismic displacement and velocity waveforms [Bock et al., 2011], a method known as seismogeodesy. We present the prototype seismogeodetic early warning system developed at Scripps and demonstrate that the seismogeodetic dataset can be used for P-wave detection, hypocenter location, and shaking onset determination. We discuss uncertainties in each of these estimates and include discussion of the sensitivity of our estimates as a function of the azimuthal distribution of monitoring stations. The seismogeodetic combination has previously been shown to be immune to magnitude saturation [Crowell et al., 2013; Melgar et al., 2015]. Rapid magnitude estimation is an important product in earthquake early warning, and is the critical metric in current tsunami hazard warnings. Using the seismogeodetic approach, we refine earthquake magnitude scaling using P-wave amplitudes (Pd) and peak ground displacements (PGD) for a

  19. Evidence for a magnitude effect in probability discounting with pigeons.

    PubMed

    Grace, Randolph C; McLean, Anthony P

    2015-10-01

    A magnitude effect in probability discounting is well established with humans, in which the value of a larger reward decreases more with uncertainty than the value of a smaller reward. We report 2 experiments that show that an analogous result is obtained with pigeons choosing between probabilistic food rewards in a 2-component concurrent-chains procedure. In Experiment 1, the terminal links delivered large (4-s access to food) and small (2-s access to food) rewards with either 100% or 50% probability across components. Preference for the larger reward was greater in the 100% component. In Experiment 2, the terminal links delivered reinforcement on 100% or 50% of terminal links and the rewards were large (4-s access to food) or small (2-s access to food) across components. Preference for the 100% alternative was greater when rewards were large. In both experiments, results indicate that the value of the larger reward decreased more when its probability was 50% than the value of the smaller reward, confirming the magnitude effect, and were similar regardless of whether the food and no-food outcomes for the 50% terminal links were differentially signaled. Results were predicted by an extension of the cumulative decision model (Christensen & Grace, 2010; Grace & McLean, 2006), which accounts for the effects of magnitude and probability on choice and can also explain the apparently contradictory results of prior research on the magnitude effect in delay discounting with pigeons. The model shows that a single process can account for delay and probability discounting in nonhumans, including the opposite effects of reward magnitude.

  20. Head Impact Magnitude in American High School Football.

    PubMed

    Schmidt, Julianne D; Guskiewicz, Kevin M; Mihalik, Jason P; Blackburn, J Troy; Siegmund, Gunter P; Marshall, Stephen W

    2016-08-01

    To describe determinants of head impact magnitudes between various play aspects in high school football. Thirty-two high school American football players wore Head Impact Telemetry System instrumented helmets to capture head impact magnitude (linear acceleration, rotational acceleration, and Head Impact Technology severity profile [HITsp]). We captured and analyzed video from 13 games (n = 3888 viewable head impacts) to determine the following play aspects: quarter, impact cause, play type, closing distance, double head impact, player's stance, player's action, direction of gaze, athletic readiness, level of anticipation, player stationary, ball possession, receiving ball, and snapping ball. We conducted random intercepts general linear mixed models to assess the differences in head impact magnitude between play aspects (α = 0.05). The following aspects resulted in greater head impact magnitude: impacts during the second quarter (HITsp: P = .03); contact with another player (linear, rotational, HITsp: P < .001); initial head impact when the head is struck twice (linear, rotational, HITsp: P < .001); longer closing distances, especially when combined with a 3-point stance or when being struck in the head (linear: P = .03); the 2-point stance (linear, rotational, HITsp: P < .001); and offensive linemen not snapping the ball compared with those snapping the ball (rotational: P = .02, HITsp: P = .02). Preventing head impacts caused by contact with another player may reduce head impact magnitude in high school football. Rule or coaching changes that reduce collisions after long closing distances, especially when combined with the 3-point stance or when a player is being struck in the head, should be considered. Copyright © 2016 by the American Academy of Pediatrics.

  1. Individual Movement Variability Magnitudes Are Explained by Cortical Neural Variability.

    PubMed

    Haar, Shlomi; Donchin, Opher; Dinstein, Ilan

    2017-09-13

    Humans exhibit considerable motor variability even across trivial reaching movements. This variability can be separated into specific kinematic components such as extent and direction that are thought to be governed by distinct neural processes. Here, we report that individual subjects (males and females) exhibit different magnitudes of kinematic variability, which are consistent (within individual) across movements to different targets and regardless of which arm (right or left) was used to perform the movements. Simultaneous fMRI recordings revealed that the same subjects also exhibited different magnitudes of fMRI variability across movements in a variety of motor system areas. These fMRI variability magnitudes were also consistent across movements to different targets when performed with either arm. Cortical fMRI variability in the posterior-parietal cortex of individual subjects explained their movement-extent variability. This relationship was apparent only in posterior-parietal cortex and not in other motor system areas, thereby suggesting that individuals with more variable movement preparation exhibit larger kinematic variability. We therefore propose that neural and kinematic variability are reliable and interrelated individual characteristics that may predispose individual subjects to exhibit distinct motor capabilities.SIGNIFICANCE STATEMENT Neural activity and movement kinematics are remarkably variable. Although intertrial variability is rarely studied, here, we demonstrate that individual human subjects exhibit distinct magnitudes of neural and kinematic variability that are reproducible across movements to different targets and when performing these movements with either arm. Furthermore, when examining the relationship between cortical variability and movement variability, we find that cortical fMRI variability in parietal cortex of individual subjects explained their movement extent variability. This enabled us to explain why some subjects

  2. New Geomagnetic Index (idv) Measuring Magnitude of Interplanetary Magnetic Field

    NASA Astrophysics Data System (ADS)

    Svalgaard, L.; Cliver, E. W.

    2003-12-01

    We present a new long-term geomagnetic index (the IDV index) which has the property that it is a proxy of the magnitude of the interplanetary magnetic field at the Earth. The index is constructed (for any given station) as the monthly (or yearly) average of the differences (taken without regard to sign) of the hourly mean values of the hour following local midnight between two consecutive days. It is similar to the classical u-measure except that the differences are between one-hour values rather than daily means. The IDV index has a strong correlation (r=0.88) with the magnitude, B, of the IMF, but is uncorrelated (r=0.09) with the solar wind speed, V. Because other indices (e.g. aa and our own IHV) are strongly correlated with BV**2, the IDV index fords a way of separating the influence of B and V and thus determining both.

  3. Magnitude and frequency of floods in western Oregon

    USGS Publications Warehouse

    Harris, David Dell; Hubbard, Larry L.; Hubbard, Lawrence E.

    1979-01-01

    A method for estimating the magnitude and frequency of floods is presented for unregulated streams in western Oregon. Equations relating flood magnitude to basin characteristics were developed for exceedance probabilities of 0.5 to 0.01 (2- to 100-year recurrence intervals). Separate equations are presented for four regions: Coast, Willamette, Rogue-Umpqua, and High Cascades. Also presented are values of flood discharges for selected exceedance probabilities and of basin characteristics for all gaging stations used in the analysis. Included are data for 230 stations in Oregon, 6 stations in southwestern Washington, and 3 stations in northwestern California. Drainage areas used in the analysis range from 0.21 to 7,280 square miles. Also included are maximum discharges for all western Oregon stations used in the analysis. (Woodard-USGS)

  4. Resistance to change as a function of concurrent reinforcer magnitude.

    PubMed

    Rau, J C; Pickering, L D; McLean, A P

    1996-12-01

    Six pigeons responded on two keys in each of three signalled multiple-schedule components, and resistance to disruption of responding on one (target) key by extinction and by response-independent food presented during inter-component blackouts was studied. Alternative reinforcement of different magnitudes was contingent on pecking a non-target key in two components, and in the third only the target response was reinforced. Resistance to change varied with the overall quantity of reinforcement in the component, regardless of whether reinforcers were contingent on the target or non-target response, but did not differ across the two key locations. These results using different magnitudes of reinforcement confirm previous findings using rate of reinforcement as the variable, and suggest that resistance to change is dependent on stimulus-reinforcer rather than response-reinforcer contingencies.

  5. How are number words mapped to approximate magnitudes?

    PubMed

    Sullivan, Jessica; Barner, David

    2013-01-01

    How do we map number words to the magnitudes they represent? While much is known about the developmental trajectory of number word learning, the acquisition of the counting routine, and the academic correlates of estimation ability, previous studies have yet to describe the mechanisms that link number words to nonverbal representations of number. We investigated two mechanisms: associative mapping and structure mapping. Four dot array estimation tasks found that adults' ability to match a number word to one of two discriminably different sets declined as a function of set size and that participants' estimates of relatively large, but not small, set sizes were influenced by misleading feedback during an estimation task. We propose that subjects employ structure mappings for linking relatively large number words to set sizes, but rely chiefly on item-by-item associative mappings for smaller sets. These results indicate that both inference and association play important roles in mapping number words to approximate magnitudes.

  6. 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.

  7. Sensori-motor spatial training of number magnitude representation.

    PubMed

    Fischer, Ursula; Moeller, Korbinian; Bientzle, Martina; Cress, Ulrike; Nuerk, Hans-Christoph

    2011-02-01

    An adequately developed spatial representation of number magnitude is associated with children's general arithmetic achievement. Therefore, a new spatial-numerical training program for kindergarten children was developed in which presentation and response were associated with a congruent spatial numerical representation. In particular, children responded by a full-body spatial movement on a digital dance mat in a magnitude comparison task. This spatial-numerical training was more effective than a non-spatial control training in enhancing children's performance on a number line estimation task and a subtest of a standardized mathematical achievement battery (TEDI-MATH). A mediation analysis suggested that these improvements were driven by an improvement of children's mental number line representation and not only by unspecific factors such as attention or motivation. These results suggest a benefit of spatial numerical associations. Rather than being a merely associated covariate, they work as an independently manipulated variable which is functional for numerical development.

  8. A new method for the estimation of the completeness magnitude

    NASA Astrophysics Data System (ADS)

    Godano, C.

    2017-02-01

    The estimation of the magnitude of completeness mc have strong consequences in any statistical analysis of seismic catalogue and in the evaluation of the seismic hazard. Here a new method for its estimation is presented. The goodness of the method has been tested using 104 simulated catalogues. Then the method has been applied to five experimental seismic catalogues: Greece, Italy, Japan, Northern California and Southern California.

  9. 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.

  10. 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.

  11. Estimation of continuous object distributions from limited Fourier magnitude measurements

    NASA Astrophysics Data System (ADS)

    Byrne, Charles L.; Fiddy, Michael A.

    1987-01-01

    From finite complex spectral data one can construct a continuous object with a given support that is consistent with the data. Given Fourier magnitude data only, one can choose the phases arbitrarily in the above construction. The energy in the extrapolated spectrum is phase-dependent and provides a cost function to be used in phase retrieval. The minimization process is performed iteratively, using an algorithm that can be viewed as a combination of Gerchberg-Papoulis and Fienup error reduction.

  12. The Absolute Magnitudes of Type Ia Supernovae in the Ultraviolet

    NASA Astrophysics Data System (ADS)

    Brown, Peter J.; Roming, Peter W. A.; Milne, Peter; Bufano, Filomena; Ciardullo, Robin; Elias-Rosa, Nancy; Filippenko, Alexei V.; Foley, Ryan J.; Gehrels, Neil; Gronwall, Caryl; Hicken, Malcolm; Holland, Stephen T.; Hoversten, Erik A.; Immler, Stefan; Kirshner, Robert P.; Li, Weidong; Mazzali, Paolo; Phillips, Mark M.; Pritchard, Tyler; Still, Martin; Turatto, Massimo; Vanden Berk, Daniel

    2010-10-01

    We examine the absolute magnitudes and light-curve shapes of 14 nearby (redshift z = 0.004-0.027) Type Ia supernovae (SNe Ia) observed in the ultraviolet (UV) with the Swift Ultraviolet/Optical Telescope. Colors and absolute magnitudes are calculated using both a standard Milky Way extinction law and one for the Large Magellanic Cloud that has been modified by circumstellar scattering. We find very different behavior in the near-UV filters (uvw1 rc covering ~2600-3300 Å after removing optical light, and u ≈ 3000-4000 Å) compared to a mid-UV filter (uvm2 ≈2000-2400 Å). The uvw1 rc - b colors show a scatter of ~0.3 mag while uvm2-b scatters by nearly 0.9 mag. Similarly, while the scatter in colors between neighboring filters is small in the optical and somewhat larger in the near-UV, the large scatter in the uvm2 - uvw1 colors implies significantly larger spectral variability below 2600 Å. We find that in the near-UV the absolute magnitudes at peak brightness of normal SNe Ia in our sample are correlated with the optical decay rate with a scatter of 0.4 mag, comparable to that found for the optical in our sample. However, in the mid-UV the scatter is larger, ~1 mag, possibly indicating differences in metallicity. We find no strong correlation between either the UV light-curve shapes or the UV colors and the UV absolute magnitudes. With larger samples, the UV luminosity might be useful as an additional constraint to help determine distance, extinction, and metallicity in order to improve the utility of SNe Ia as standardized candles.

  13. THE ABSOLUTE MAGNITUDES OF TYPE Ia SUPERNOVAE IN THE ULTRAVIOLET

    SciTech Connect

    Brown, Peter J.; Roming, Peter W. A.; Ciardullo, Robin; Gronwall, Caryl; Hoversten, Erik A.; Pritchard, Tyler; Milne, Peter; Bufano, Filomena; Mazzali, Paolo; Elias-Rosa, Nancy; Filippenko, Alexei V.; Li Weidong; Foley, Ryan J.; Hicken, Malcolm; Kirshner, Robert P.; Gehrels, Neil; Holland, Stephen T.; Immler, Stefan; Phillips, Mark M.; Still, Martin

    2010-10-01

    We examine the absolute magnitudes and light-curve shapes of 14 nearby (redshift z = 0.004-0.027) Type Ia supernovae (SNe Ia) observed in the ultraviolet (UV) with the Swift Ultraviolet/Optical Telescope. Colors and absolute magnitudes are calculated using both a standard Milky Way extinction law and one for the Large Magellanic Cloud that has been modified by circumstellar scattering. We find very different behavior in the near-UV filters (uvw1{sub rc} covering {approx}2600-3300 A after removing optical light, and u {approx} 3000-4000 A) compared to a mid-UV filter (uvm2 {approx}2000-2400 A). The uvw1{sub rc} - b colors show a scatter of {approx}0.3 mag while uvm2-b scatters by nearly 0.9 mag. Similarly, while the scatter in colors between neighboring filters is small in the optical and somewhat larger in the near-UV, the large scatter in the uvm2 - uvw1 colors implies significantly larger spectral variability below 2600 A. We find that in the near-UV the absolute magnitudes at peak brightness of normal SNe Ia in our sample are correlated with the optical decay rate with a scatter of 0.4 mag, comparable to that found for the optical in our sample. However, in the mid-UV the scatter is larger, {approx}1 mag, possibly indicating differences in metallicity. We find no strong correlation between either the UV light-curve shapes or the UV colors and the UV absolute magnitudes. With larger samples, the UV luminosity might be useful as an additional constraint to help determine distance, extinction, and metallicity in order to improve the utility of SNe Ia as standardized candles.

  14. 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. © 2013, National Ground Water Association.

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

    SciTech Connect

    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 multichannel 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.

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

    DOE PAGES

    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

  17. 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.

  18. Reinforcement magnitude and pausing on progressive-ratio schedules

    PubMed Central

    Baron, Alan; Mikorski, Jeffrey; Schlund, Michael

    1992-01-01

    Rats responded under progressive-ratio schedules for sweetened milk reinforcers; each session ended when responding ceased for 10 min. Experiment 1 varied the concentration of milk and the duration of postreinforcement timeouts. Postreinforcement pausing increased as a positively accelerated function of the size of the ratio, and the rate of increase was reduced as a function of concentration and by timeouts of 10 s or longer. Experiment 2 varied reinforcement magnitude within sessions (number of dipper operations per reinforcer) in conjunction with stimuli correlated with the upcoming magnitude. In the absence of discriminative stimuli, pausing was longer following a large reinforcer than following a small one. Pauses were reduced by a stimulus signaling a large upcoming reinforcer, particularly at the highest ratios, and the animals tended to quit responding when the past reinforcer was large and the stimulus signaled that the next one would be small. Results of both experiments revealed parallels between responding under progressive-ratio schedules and other schedules containing ratio contingencies. Relationships between pausing and magnitude suggest that ratio pausing is under the joint control of inhibitory properties of the past reinforcer and excitatory properties of stimuli correlated with the upcoming reinforcer, rather than under the exclusive control of either factor alone. PMID:16812671

  19. 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.

  20. 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

  1. SENSE Phase-Constrained Magnitude Reconstruction With Iterative Phase Refinement

    PubMed Central

    Lew, Calvin; Pineda, Angel R.; Clayton, David; Spielman, Dan; Chan, Frandics; Bammer, Roland

    2012-01-01

    Conventional sensitivity encoding (SENSE) reconstruction is based on equations in the complex domain. However, for many MRI applications only the magnitude is relevant. If there exists an estimate of the underlying phase information, a magnitude-only phase-constrained reconstruction can help to improve the conditioning of the SENSE reconstruction problem. Consequently, this reduces g-factor-related noise enhancement. In previous attempts at phase-constrained SENSE reconstruction, image quality was hampered by strong aliasing artifacts resulting from inadequate phase estimates and high sensitivity to phase errors. If a full-resolution phase image is used, a significant reduction in aliasing errors and better noise properties compared to SENSE can be obtained. An iterative scheme that improves the phase estimate to better approximate the phase is presented. The mathematical framework of the new approach is provided together with comparisons of conventional SENSE, phase-constrained SENSE, and the new phase-refinement method. Both theory and experimental verification demonstrate significantly better noise performance at high reduction factors, i.e., close to the theoretical limit. For applications that need only magnitude data, an iterative phase-constrained SENSE reconstruction can provide substantial SNR improvement over SENSE reconstruction and less artifacts than phase-constrained SENSE. PMID:17969127

  2. 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.

  3. 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.

  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. Investigation of cress root gravisensing und low magnitude acceleration

    NASA Astrophysics Data System (ADS)

    Svegzdiene, D.; Rakleviciene, D.

    2005-08-01

    The sensitivity of gravisensors and amyloplast location within statocytes in cress roots grown at 1 g were investigated under low magnitude transverse accelerations on a centrifuge-clinostat with two- orthogonal axes. After stimulation by acceleration of 0.0042 and 0.019 g and rotation on a clinostat, a relationship between gravitropic response of roots and the stimulus dose was analyzed. The threshold dose was evaluated to be about 2 to 4 g×s, depending on the magnitude of acceleration. Statolith positioning was studied in roots on applying accelerations in the range 0.0011-0.1564 g. Structural analysis of statocytes revealed only a slight transverse displacement of amyloplasts in response to the 60 g×s dose (0.0045g × 4h). It exceeded considerably the threshold dose evaluated for roots under similar acceleration. Our data allow suggesting that a slight, however, transient, translocation of amyloplasts under the action of low magnitude acceleration may trigger and transmit the gravitropic stimulus.

  6. 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

  7. Automated Determination of Magnitude and Source Extent of Large Earthquakes

    NASA Astrophysics Data System (ADS)

    Wang, Dun

    2017-04-01

    Rapid determination of earthquake magnitude is of importance for estimating shaking damages, and tsunami hazards. However, due to the complexity of source process, accurately estimating magnitude for great earthquakes in minutes after origin time is still a challenge. Mw is an accurate estimate for large earthquakes. However, calculating Mw requires the whole wave trains including P, S, and surface phases, which takes tens of minutes to reach stations at tele-seismic distances. To speed up the calculation, methods using W phase and body wave are developed for fast estimating earthquake sizes. Besides these methods that involve Green's Functions and inversions, there are other approaches that use empirically simulated relations to estimate earthquake magnitudes, usually for large earthquakes. The nature of simple implementation and straightforward calculation made these approaches widely applied at many institutions such as the Pacific Tsunami Warning Center, the Japan Meteorological Agency, and the USGS. Here we developed an approach that was originated from Hara [2007], estimating magnitude by considering P-wave displacement and source duration. We introduced a back-projection technique [Wang et al., 2016] instead to estimate source duration using array data from a high-sensitive seismograph network (Hi-net). The introduction of back-projection improves the method in two ways. Firstly, the source duration could be accurately determined by seismic array. Secondly, the results can be more rapidly calculated, and data derived from farther stations are not required. We purpose to develop an automated system for determining fast and reliable source information of large shallow seismic events based on real time data of a dense regional array and global data, for earthquakes that occur at distance of roughly 30°- 85° from the array center. This system can offer fast and robust estimates of magnitudes and rupture extensions of large earthquakes in 6 to 13 min (plus

  8. Estimating The Magnitude Ms of Historical Earthquakes From Macroseismic Observations

    NASA Astrophysics Data System (ADS)

    Kaiser, D.; Gutdeutsch, R.; Jentzsch, G.

    Magnitudes of earthquakes earlier than 1900 are derived from macroseismic observa- tions, i.e. the maximum intensity I0, or isoseismal radii RI of different intensities I and the focal depth h. The purpose of our study is to compare the importance of I0 and RI as input parameters for the estimation of the surface wave magnitude MS of his- torical earthquakes and to derive appropriate empirical relationships. We use carefully selected instrumental parts (since 1900) of 2 earthquake catalogues: Kárník 1996 (Eu- rope and the Mediterranean) and Shebalin et al. 1998 (Central and Eastern Europe). In order to establish relationships we use the orthogonal regression because we presume that all parameters are in error and because it has the advantage to provide reversible regression equations. Estimation of MS from I0 and h. As correlation analysis of Kárník's catalogue shows no significant influence of h on the relation between MS and I0 we obtain MS = 0.55I0+1.26, with derived equivalent standard error MS = +/-0.44 and I0 = +/-0.86. The practical use of this relationship is limited due to rather large errors. In addition we observe systematic regional variations which need further investigation. We were able to apply much more stringent selection criteria to the Shebalin catalogue and found a substantial improvement of the correlation when considering the influence of h [km], in contrast to Kárník's catalogue. We obtain MS = 0.65I0 + 1.90log(h) - 1.62 with error MS = +/-0.21. We recommend this equation for application. Estimation of MS from average isoseismal radii RI. In order to establish a relation- ship between MS and RI we apply a theoretically based model which takes into account both exponential decay and geometrical spreading factor. We find MS = 0.695I + 2.14 log (RI) + 0.00329RI - 1.93 with MS = +/-0.32. Here I is the macroseismic intensity (I = 3 ... 9) of the isoseismal RI [km]. With this equation it is possible to reliably estimate MS and we recommend

  9. 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

  10. 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)

  11. 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.

  12. 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)

  13. 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,…

  14. 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)

  15. 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)

  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. Early Warning for Large Magnitude Earthquakes: Is it feasible?

    NASA Astrophysics Data System (ADS)

    Zollo, A.; Colombelli, S.; Kanamori, H.

    2011-12-01

    The mega-thrust, Mw 9.0, 2011 Tohoku earthquake has re-opened the discussion among the scientific community about the effectiveness of Earthquake Early Warning (EEW) systems, when applied to such large events. Many EEW systems are now under-testing or -development worldwide and most of them are based on the real-time measurement of ground motion parameters in a few second window after the P-wave arrival. Currently, we are using the initial Peak Displacement (Pd), and the Predominant Period (τc), among other parameters, to rapidly estimate the earthquake magnitude and damage potential. A well known problem about the real-time estimation of the magnitude is the parameter saturation. Several authors have shown that the scaling laws between early warning parameters and magnitude are robust and effective up to magnitude 6.5-7; the correlation, however, has not yet been verified for larger events. The Tohoku earthquake occurred near the East coast of Honshu, Japan, on the subduction boundary between the Pacific and the Okhotsk plates. The high quality Kik- and K- networks provided a large quantity of strong motion records of the mainshock, with a wide azimuthal coverage both along the Japan coast and inland. More than 300 3-component accelerograms have been available, with an epicentral distance ranging from about 100 km up to more than 500 km. This earthquake thus presents an optimal case study for testing the physical bases of early warning and to investigate the feasibility of a real-time estimation of earthquake size and damage potential even for M > 7 earthquakes. In the present work we used the acceleration waveform data of the main shock for stations along the coast, up to 200 km epicentral distance. We measured the early warning parameters, Pd and τc, within different time windows, starting from 3 seconds, and expanding the testing time window up to 30 seconds. The aim is to verify the correlation of these parameters with Peak Ground Velocity and Magnitude

  18. 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.

  19. 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.

  20. The effects of reinforcement magnitude on skill acquisition for children with autism.

    PubMed

    Paden, Amber R; Kodak, Tiffany

    2015-12-01

    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 large-magnitude reinforcer, preference did not predict the magnitude that produced the fastest skill acquisition.

  1. The Earthquake Frequency-Magnitude Distribution Functional Shape

    NASA Astrophysics Data System (ADS)

    Mignan, A.

    2012-04-01

    Knowledge of the completeness magnitude Mc, magnitude above which all earthquakes are detected, is a prerequisite to most seismicity analyses. Although computation of Mc is done routinely, different techniques often result in different values. Since an incorrect estimate can lead to under-sampling or worse to an erroneous estimate of the parameters of the Gutenberg-Richter (G-R) law, a better assessment of the deviation from the G-R law and thus of the earthquake detectability is of paramount importance to correctly estimate Mc. This is especially true for refined mapping of seismicity parameters such as in earthquake forecast models. The capacity of a seismic network to detect small earthquakes can be evaluated by investigating the functional shape of the earthquake Frequency-Magnitude Distribution (FMD). The non-cumulative FMD takes the form N(m) ∝ exp(-βm)q(m) where N(m) is the number of events of magnitude m, exp(-βm) the G-R law and q(m) a probability function. q(m) is commonly defined as the cumulative Normal distribution to describe the gradual curvature often observed in bulk FMDs. Recent results however show that this gradual curvature is potentially due to spatial heterogeneities in Mc, meaning that the functional shape of the elemental (local) FMD still has to be described. Based on preliminary observations, we propose an exponential detection function of the form q(m) = exp(κ(m-Mc)) for m < Mc and q(m) = 1 for m ≥ Mc, which leads to an FMD of angular shape. The two FMD models (gradually curved and angular) are compared in Southern California and Nevada. We show that the angular shaped FMD model better describes the elemental FMD and that the sum of elemental FMDs with different Mc(x,y) leads to the gradually curved FMD at the regional scale. We show that the proposed model (1) provides more robust estimates of Mc, (2) better estimates local b-values, and (3) gives an insight into earthquake detectability properties by using seismicity as a proxy

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Characteristic magnitude of subduction earthquake and upper plate stiffness

    NASA Astrophysics Data System (ADS)

    Sakaguchi, A.; Yamamoto, Y.; Hashimoto, Y.; Harris, R. N.; Vannucchi, P.; Petronotis, K. E.

    2013-12-01

    Variations in earthquake magnitude and recurrence intervals of fault behavior are best understood in the context of regional tectonics. Convergent margins may be divided into two end-member types termed erosive and accretionary plate boundaries (e.g. von Huene and Scholl, 1991; Clift and Vannucchi, 2004). These margins often differ greatly in in lithology, physical properties and thermal conditions. The Nankai accretionary margin has a 1300-year historical earthquake record with a recurrence interval of 100-150 years (Ando, 1975). Great earthquakes at Nankai are typically tsunamigenic and include the 1944 Tonankai (Mw=8.1) and 1946 Nankaido (Mw=8.1) earthquakes (Kanamori, 1977). In contrast, the Middle America trench offshore Costa Rica events of M=7.6 reoccur on average of every 40 years. Comparisons between these margins may produce insights into mechanisms that influence characteristic magnitudes and recurrence intervals of subduction earthquakes. The IODP Costa-Rica Seismogenesis Program (CRISP) has carried out the first step toward the deep riser drilling by characterizing the shallow lithologic, hydrologic, stress, and thermal state at offshore Osa Peninsula (Vannucchi et al., 2011; Harris et al., 2013). CRISP drilling reveals that the shallow basement of upper plate crust is forearc basin material consisting of lithic sedimentary units with terrigenous sediment accumulated at a high rate. A large sediment flux to the forearc may have originated from the uplifted back-arc Talamanca Cordillera due to Cocos-Ridge subduction (Lonsdale and Klitgord, 1978; van Andel et al., 1971). Both drilling area of the Nankai and Costa-Rica, off Osa are characterized by the subduction of young oceanic crust with high heat flow and active fluid flow (Spinelli and Wang, 2008; Spinelli and Harris, 2011; Harris et al., 2010). The P-wave velocity structure shows that upper plate body of Costa Rica is much more lithified than the Nankai margin. In frictional stick-slip system, the

  8. Evaluation of the magnitude of EBT Gafchromic film polarization effects.

    PubMed

    Butson, M J; Cheung, T; Yu, P K N

    2009-03-01

    Gafchromic EBT film, has become a main dosimetric tools for quantitative evaluation of radiation doses in radiation therapy application. One aspect of variability using EBT Gafchromic film is the magnitude of the orientation effect when analysing the film in landscape or portrait mode. This work has utilized a > 99% plane polarized light source and a non-polarized diffuse light source to investigate the absolute magnitude of EBT Gafchromic films polarization or orientation effects. Results have shown that using a non-polarized light source produces a negligible orientation effect for EBT Gafchromic film and thus the angle of orientation is not important. However, the film exhibits a significant variation in transmitted optical density with angle of orientation to polarized light producing more than 100% increase, or over a doubling of measured OD for films irradiated with x-rays up to dose levels of 5 Gy. The maximum optical density was found to be in a plane at an angle of 14 degrees +/- 7 degrees (2 SD) when the polarizing sheet is turned clockwise with respect to the film. As the magnitude of the orientation effect follows a sinusoidal shape it becomes more critical for alignment accuracy of the film with respect to the polarizing direction in the anticlockwise direction as this will place the alignment of the polarizing axes on the steeper gradient section of the sinusoidal pattern. An average change of 4.5% per 5 degrees is seen for an anticlockwise polarizer rotation where as the effect is 1.2% per 5 degrees for an clockwise polarizer rotation. This may have consequences to the positional accuracy of placement of the EBT Gafchromic film on a scanner as even a 1 degree alignment error can cause an approximate 1% error in analysis. The magnitude of the orientation effect is therefore dependant on the degree of polarization of the scanning light source and can range from negligible (diffuse LED light source) through to more than 100% or doubling of OD variation

  9. 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.

  10. 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.

  11. Calibration of the local magnitude scale ( M L ) for Peru

    NASA Astrophysics Data System (ADS)

    Condori, Cristobal; Tavera, Hernando; Marotta, Giuliano Sant'Anna; Rocha, Marcelo Peres; França, George Sand

    2017-07-01

    We propose a local magnitude scale ( M L ) for Peru, based on the original Richter definition, using 210 seismic events between 2011 and 2014, recorded by 35 broadband stations of the National Seismic Network operated by the Geophysical Institute of Peru. In the solution model, we considered 1057 traces of maximum amplitude records on the vertical channel from simulated Wood-Anderson seismograms of shallow events (depths between 0 and 60 km) and hypocentral distances less than 600 km. The attenuation factor has been evaluated in terms of geometrical spreading and anelastic attenuation coefficients. The magnitude M L was defined as M L = L o g 10 A W A +1.5855 L o g 10( R/100)+0.0008( R-100)+3± S, where, A W A is the displacement amplitude in millimeters (Wood-Anderson), R is the hypocentral distance (km), and S is the station correction. The results obtained for M L have good correlation with the m b , M s and M w values reported the ISC and NEIC. The anelastic attenuation curve obtained has a similar behavior to that other highly seismic regions. Station corrections were determined for all stations during the regression analysis resulting in values ranging between -0.97 and +0.73, suggesting a strong influence of local site effects on amplitude.

  12. Hydrophobic ion hydration and the magnitude of the dipole potential.

    PubMed Central

    Schamberger, Jens; Clarke, Ronald J

    2002-01-01

    The magnitude of the dipole potential of lipid membranes is often estimated from the difference in conductance between the hydrophobic ions, tetraphenylborate, and tetraphenylarsonium or tetraphenylphosphonium. The calculation is based on the tetraphenylarsonium-tetraphenylborate hypothesis that the magnitude of the hydration energies of the anions and cations are equal (i.e., charge independent), so that their different rates of transport across the membrane are solely due to differential interactions with the membrane phase. Here we investigate the validity of this assumption by quantum mechanical calculations of the hydration energies. Tetraphenylborate (Delta G(hydr) = -168 kJ mol(-1)) was found to have a significantly stronger interaction with water than either tetraphenylarsonium (Delta G(hydr) = -145 kJ mol(-1)) or tetraphenylphosphonium (Delta G(hydr) = -157 kJ mol(-1)). Taking these differences into account, literature conductance data were recalculated to yield values of the dipole potential 57 to 119 mV more positive in the membrane interior than previous estimates. This may partly account for the discrepancy of at least 100 mV generally observed between dipole potential values calculated from lipid monolayers and those determined on bilayers. PMID:12023231

  13. 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

  14. Dependence of the aftershock flow on the main shock magnitude

    NASA Astrophysics Data System (ADS)

    Guglielmi, A. V.; Zavyalov, A. D.; Zotov, O. D.; Lavrov, I. P.

    2017-01-01

    Previously, we predicted and then observed in practice the property of aftershocks which consists in the statistically regular clustering of events in time during the first hours after the main shock. The characteristic quasi-period of clustering is three hours. This property is associated with the cumulative action of the surface waves converging to the epicenter, whereas the quasi-period is mainly determined by the time delay of the round-the-world seismic echo. The quasi-period varies from case to case. In the attempt to find the cause of this variability, we have statistically explored the probable dependence of quasi-period on the magnitude of the main shock. In this paper, we present the corresponding result of analyzing global seismicity from the USGS/NEIC earthquake catalog. We succeeded in finding a significant reduction in the quasiperiod of the strong earthquakes clustering with growth in the magnitude of the main shock. We suggest the interpretation of this regularity from the standpoint of the phenomenological theory of explosive instability. It is noted that the phenomenon of explosive instability is fairly common in the geophysical media. The examples of explosive instability in the radiation belt and magnetospheric tail are presented. The search for the parallels in the evolution of explosive instability in the lithosphere and magnetosphere of the Earth will enrich both the physics of the earthquakes and physics of the magnetospheric pulsations.

  15. Calibration of the local magnitude scale (M L ) for Peru

    NASA Astrophysics Data System (ADS)

    Condori, Cristobal; Tavera, Hernando; Marotta, Giuliano Sant'Anna; Rocha, Marcelo Peres; França, George Sand

    2017-02-01

    We propose a local magnitude scale (M L ) for Peru, based on the original Richter definition, using 210 seismic events between 2011 and 2014, recorded by 35 broadband stations of the National Seismic Network operated by the Geophysical Institute of Peru. In the solution model, we considered 1057 traces of maximum amplitude records on the vertical channel from simulated Wood-Anderson seismograms of shallow events (depths between 0 and 60 km) and hypocentral distances less than 600 km. The attenuation factor has been evaluated in terms of geometrical spreading and anelastic attenuation coefficients. The magnitude M L was defined as M L = L o g 10 A W A +1.5855L o g 10(R/100)+0.0008(R-100)+3±S, where, A W A is the displacement amplitude in millimeters (Wood-Anderson), R is the hypocentral distance (km), and S is the station correction. The results obtained for M L have good correlation with the m b , M s and M w values reported the ISC and NEIC. The anelastic attenuation curve obtained has a similar behavior to that other highly seismic regions. Station corrections were determined for all stations during the regression analysis resulting in values ranging between -0.97 and +0.73, suggesting a strong influence of local site effects on amplitude.

  16. 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.

  17. 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].

  18. 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).

  19. Magnitude-dependent response of osteoblasts regulated by compressive stress

    PubMed Central

    Shen, Xiao-qing; Geng, Yuan-ming; Liu, Ping; Huang, Xiang-yu; Li, Shu-yi; Liu, Chun-dong; Zhou, Zheng; Xu, Ping-ping

    2017-01-01

    The present study aimed to investigate the role of magnitude in adaptive response of osteoblasts exposed to compressive stress. Murine primary osteoblasts and MC3T3-E1 cells were exposed to compressive stress (0, 1, 2, 3, 4, and 5 g/cm2) in 3D culture. Cell viability was evaluated, and expression levels of Runx2, Alp, Ocn, Rankl, and Opg were examined. ALP activity in osteoblasts and TRAP activity in RAW264.7 cells co-cultured with MC3T3-E1 cells were assayed. Results showed that compressive stress within 5.0 g/cm2 did not influence cell viability. Both osteoblastic and osteoblast-regulated osteoclastic differentiation were enhanced at 2 g/cm2. An increase in stress above 2 g/cm2 did not enhance osteoblastic differentiation further but significantly inhibited osteoblast-regualted osteoclastic differentiation. This study suggested that compressive stress regulates osteoblastic and osteoclastic differentiation through osteoblasts in a magnitude-dependent manner. PMID:28317941

  20. Millennial scale variability in high magnitude flooding across Britain

    NASA Astrophysics Data System (ADS)

    Macdonald, N.

    2014-09-01

    The last decade has witnessed severe flooding across much of the globe, but have these floods really been exceptional? Globally, relatively few instrumental river flow series extend beyond 50 years, with short records presenting significant challenges in determining flood risk from high-magnitude floods. A perceived increase in extreme floods in recent years has decreased public confidence in conventional flood risk estimates; the results affect society (insurance costs), individuals (personal vulnerability) and companies (e.g. water resource managers - flood/drought risk). Here we show how historical records from Britain have improved understanding of high magnitude floods, by examining past spatial and temporal variability. The findings identify that whilst recent floods are notable, several comparable periods of increased flooding are identifiable historically, with periods of greater frequency (flood-rich periods) or/and larger floods. The use of historical records identifies that the largest floods often transcend single catchments affecting regions and that the current flood rich period is not exceptional.

  1. High-magnitude flooding across Britain since AD 1750

    NASA Astrophysics Data System (ADS)

    Macdonald, Neil; Sangster, Heather

    2017-03-01

    The last decade has witnessed severe flooding across much of the globe, but have these floods really been exceptional? Globally, relatively few instrumental river flow series extend beyond 50 years, with short records presenting significant challenges in determining flood risk from high-magnitude floods. A perceived increase in extreme floods in recent years has decreased public confidence in conventional flood risk estimates; the results affect society (insurance costs), individuals (personal vulnerability) and companies (e.g. water resource managers). Here, we show how historical records from Britain have improved understanding of high-magnitude floods, by examining past spatial and temporal variability. The findings identify that whilst recent floods are notable, several comparable periods of increased flooding are identifiable historically, with periods of greater frequency (flood-rich periods). Statistically significant relationships between the British flood index, the Atlantic Meridional Oscillation and the North Atlantic Oscillation Index are identified. The use of historical records identifies that the largest floods often transcend single catchments affecting regions and that the current flood-rich period is not unprecedented.

  2. Bath's Law as a Consequence of Magnitude Distribution

    NASA Astrophysics Data System (ADS)

    Console, R.; Maura, M.; Lombardi, A.

    2002-12-01

    We revisit the issue of the so-called Bath's law concerning the difference D1 between the magnitude of the mainshock, M0, and the second largest shock, M1, in the same sequence. Various authors, in the past, observed that this difference is approximately equal to 1.2. Feller demonstrated in 1966 that the D1 expected value was about 0.5 given that the difference between the two largest random variables of a sample, N, exponentially distributed is also a random variable with the same distribution. Feller's proof leads to the consequence that the mainshock comes from a sample, which is different from the one of its aftershocks. A mathematical formulation of the problem is developed here, the only assumption being that all the events belong to the same self-similar set of earthquakes following the Gutenberg-Richter magnitude distribution with a constant b-value. Assuming that the number of aftershocks in each aftershock series is known, and not extremely large, this model shows a substantial dependence of D1 on the magnitude thresholds chosen for the mainshock and its largest aftershock. In this way it explains the large D1 values reported in the past. Analysis of the PDE catalog of shallow earthquakes demonstrates a good agreement between the average D1 values predicted by the theoretical model and those observed. Limiting our attention to the average D1 values, Bath's law doesn't seem to strongly contradict the Gutenberg-Richter law. Nevertheless, a detailed analysis of the observed D1 distribution shows that the Gutenberg-Richter hypothesis doesn't fully explain the experimental observations. The theoretical distribution has a larger proportion of low D1 values and a smaller proportion of high D1 values than the experimental observations. A reasonable explanation for this mismatch, which appears a minor effect with respect to what was supposed in the past, seems to consist in the byes (not assumed in the model) that the selection of clustered events produces on the

  3. 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.

  4. 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.

  5. Breach Risk Magnitude: A Quantitative Measure of Database Security

    PubMed Central

    Yasnoff, William A.

    2016-01-01

    A quantitative methodology is described that provides objective evaluation of the potential for health record system breaches. It assumes that breach risk increases with the number of potential records that could be exposed, while it decreases when more authentication steps are required for access. The breach risk magnitude (BRM) is the maximum value for any system user of the common logarithm of the number of accessible database records divided by the number of authentication steps needed to achieve such access. For a one million record relational database, the BRM varies from 5.52 to 6 depending on authentication protocols. For an alternative data architecture designed specifically to increase security by separately storing and encrypting each patient record, the BRM ranges from 1.3 to 2.6. While the BRM only provides a limited quantitative assessment of breach risk, it may be useful to objectively evaluate the security implications of alternative database organization approaches. PMID:28269923

  6. 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

  7. 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.

  8. Powerful CMD: a tool for color-magnitude diagram studies

    NASA Astrophysics Data System (ADS)

    Li, Zhong-Mu; Mao, Cai-Yan; Luo, Qi-Ping; Fan, Zhou; Zhao, Wen-Chang; Chen, Li; Li, Ru-Xi; Guo, Jian-Po

    2017-07-01

    We present a new tool for color-magnitude diagram (CMD) studies, Powerful CMD. This tool is built based on the advanced stellar population synthesis (ASPS) model, in which single stars, binary stars, rotating stars and star formation history have been taken into account. Via Powerful CMD, the distance modulus, color excess, metallicity, age, binary fraction, rotating star fraction and star formation history of star clusters can be determined simultaneously from observed CMDs. The new tool is tested via both simulated and real star clusters. Five parameters of clusters NGC 6362, NGC 6652, NGC 6838 and M67 are determined and compared to other works. It is shown that this tool is useful for CMD studies, in particular for those utilizing data from the Hubble Space Telescope (HST). Moreover, we find that inclusion of binaries in theoretical stellar population models may lead to smaller color excess compared to the case of single-star population models.

  9. 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.

  10. Fast autofocusing in digital holography using the magnitude differential.

    PubMed

    Lyu, Meng; Yuan, Caojin; Li, Dayan; Situ, Guohai

    2017-05-01

    Typical methods of automatic estimation of focusing in digital holography calculate every single reconstructed frame to get a critical function and then ascertain the focal plane by finding the extreme value of that function. Here, we propose a digital holographic autofocusing method that computes the focused distance using the first longitudinal difference of the magnitude of the reconstructed image. We demonstrate the proposed method with both numerical simulations and optical experiments of amplitude-contrast and phase-contrast objects. The results suggest that the proposed method performs better than other existing methods, in terms of applicability and computation efficiency, with potential applications in industrial and biomedical inspections where automatic focus tracking is necessary.

  11. 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.

  12. 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.

  13. 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.

  14. Technique for estimating magnitude and frequency of floods in Illinois

    USGS Publications Warehouse

    Curtis, George W.

    1977-01-01

    A technique is presented for estimating flood magnitudes at recurrence intervals ranging from 2 to 500 years, for unregulated rural streams in Illinois, with drainage areas ranging from 0.02 to 10,000 square miles. Multiple regression analyses, using streamflow data from 241 sampling sites, were used to define the flood-frequency relationships. The independent variables drainage area, slope, rainfall intensity, and an areal factor are used in the estimating equations to determine flood peaks. Examples are given to demonstrate a step-by-step procedure in computing a 100-year flood for a site on an ungaged stream and a site on a gaged stream in Illinois. The report is oriented toward planners and designers of engineering projects such as highways, bridges, culverts, flood-control structures, and drainage systems, and toward planners responsible for planning flood-plain use and establishing flood-insurance rates. (Woodard-USGS)

  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. The magnitude of basset forces in unsteady multiphase flow computations

    SciTech Connect

    Li, L.; Michaelides, E.E. . Dept. of Mechanical Engineering)

    1992-09-01

    This paper reports on the equation of motion of a small spherical particle moving in a fluid which is solved numerically with the radius of the sphere and the ratio of fluid to particle densities being parameters. The Basset force term is computed and compared to the total force on the particle for the case of turbulent flow in a duct. It is found that the Basset force may be neglected in the equation of motion of the particle only when the fluid to particle density ratio is very high and the particle diameter is greater than 1[mu]m. A dimensional analysis is also performed for the case when the particle size and the characteristic flow dimension are of the same order of magnitude. In the latter case, it is deduced that the Basset force is significant whenever the flow Reynolds number is greater than one.

  17. Magnitude and frequency of wind speed shears and associated downdrafts

    NASA Technical Reports Server (NTRS)

    Alexander, M. B.; Campbell, C. W.

    1981-01-01

    Data are presented indicating the frequency of occurrence of wind shear and downdrafts together with information on the simultaneous occurrence of these two phenomena. High resolution wind profile measurements recorded at a 150 meter ground winds tower facility were used for the analysis. From instantaneous measurements during horizontal wind speeds of gale-force and below intensity, vertical motion at the 10, 60, and 150 m levels was approximately 60 percent downward and 40 percent upward. At the 18 level the percentages were reversed. Updraft maxima were an order of magnitude or two greater than downdrafts at all levels. Frequency of vertical motion or = 9.7 kts for a year at four levels was 338 occurrences upward and 274 downward. Approximately 90 percent of these updrafts occurred at the 18 m level almost equally during summer and winter, and 65 percent of the downdrafts were at the 150 m level during summer.

  18. 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).

  19. Weight knowledge and weight magnitude: impact on lumbosacral loading.

    PubMed

    Farrag, Ahmed T; Elsayed, Walaa H; El-Sayyad, Mohsen M; Marras, William S

    2015-01-01

    Several factors can impact lumbosacral loads during lifting, including weight knowledge and weight magnitude. However, interaction between them has never been tested. This study investigated the interaction effect of these variables on lumbosacral forces and moments. Participants performed symmetrical lifts using three different weights. Weight knowledge involved known and unknown weight conditions. A biologically assisted dynamic model was used to calculate spinal loading parameters. Weight impacted all variables, while knowledge impacted only compression, by a moderate amount (5%), and spinal moments. Lifting a lightweight resulted in a difference of 16% and 7.2% between knowledge conditions for compression and anterior-posterior shear forces, respectively, compared with a negligible difference of < 1% when lifting a heavy weight. Increased spinal loading with light unknown weight can be attributed to increased muscular co-contraction. Weight knowledge is important to consider at low weight levels as it can increase tissue loading to values equivalent to lifting a heavier weight.

  20. The Extragalactic Distance Database: Color-Magnitude Diagrams

    NASA Astrophysics Data System (ADS)

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

    2009-08-01

    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.

  1. Direct magnitude estimation and interval scaling of hypernasality.

    PubMed

    Whitehill, Tara L; Lee, Alice S Y; Chun, Joyce C

    2002-02-01

    Hypernasality is most commonly assessed using equal-appearing interval (EAI) scaling. Recently, the validity of EAI scaling for the evaluation of hypernasality has been questioned. The issue of validity rests on the psychophysical nature of the dimension to be rated. The purpose of this study was to compare EAI scaling with direct magnitude estimation (DME), in order to determine whether EAI scaling is a valid procedure for the evaluation of hypernasality. Connected speech samples from 20 individuals with repaired cleft palate and hypernasality were used. Twenty listeners undertook the listening tasks, which included EAI scaling, DME with modulus (DME-M), and DME without modulus (DME-WM). The results showed a curvilinear relationship between EAI and DME-M and between EAI and DME-WM, suggesting that EAI may not be a valid method for the evaluation of hypernasality; DME is recommended.

  2. 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.

  3. Reevaluating the two-representation model of numerical magnitude processing.

    PubMed

    Jiang, Ting; Zhang, Wenfeng; Wen, Wen; Zhu, Haiting; Du, Han; Zhu, Xiangru; Gao, Xuefei; Zhang, Hongchuan; Dong, Qi; Chen, Chuansheng

    2016-01-01

    One debate in mathematical cognition centers on the single-representation model versus the two-representation model. Using an improved number Stroop paradigm (i.e., systematically manipulating physical size distance), in the present study we tested the predictions of the two models for number magnitude processing. The results supported the single-representation model and, more importantly, explained how a design problem (failure to manipulate physical size distance) and an analytical problem (failure to consider the interaction between congruity and task-irrelevant numerical distance) might have contributed to the evidence used to support the two-representation model. This study, therefore, can help settle the debate between the single-representation and two-representation models.

  4. 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.

  5. EXTENT AND MAGNITUDE OF CATECHOLAMINE SURGE IN PEDIATRIC BURNED PATIENTS

    PubMed Central

    Kulp, Gabriela A; Herndon, David N.; Lee, Jong O.; Suman, Oscar E.; Jeschke, Marc G

    2009-01-01

    Increased catecholamine (CA) levels after severe burn are associated with stress, inflammation, hypermetabolism and impaired immune function. The CA secretion profiles in burned patients are not well described. Mechanisms, duration and extent of CA surge are unknown. The purpose of this large unicenter study was to evaluate the extent and magnitude of CA surge following severe burn in pediatric patients. Patients admitted between 1996 and 2008 were enrolled in this study. Twenty-four-hour urine collections were performed during acute hospitalization and up to 2 years post burn. Results from the samples collected from 12 normal, healthy volunteers were compared with the data from the burned patients. Relevant demographic and clinical information was obtained from Medical Records. Student’s t-test and one way ANOVA were used to analyze the data where appropriate. Significance was accepted at p<0.05. Four-hundred thirteen patients were enrolled in this study, 17 patients died during acute hospitalization. Burn caused a marked stress and inflammatory response, indicated by massive tachycardia and elevated pro-inflammatory cytokines. In burned patients, CA levels are consistently and significantly modulated after burn when compared to the levels in normal, healthy volunteers. CA levels were significantly higher in males compared to females, correlated with burn size in burns over 40% and were increased in older children. There were differences over time in survivors vs. non-survivors, with CA levels significantly higher in non-survivors at 2 time points. Inflammatory cytokines show a similar profile during the study period. Our study gives clinicians a useful insight into the extent and magnitude of CA elevation to better design treatment strategies. PMID:20407405

  6. Honeybees learn the sign and magnitude of reward variations.

    PubMed

    Gil, Mariana; De Marco, Rodrigo J

    2009-09-01

    In this study, we asked whether honeybees learn the sign and magnitude of variations in the level of reward. We designed an experiment in which bees first had to forage on a three-flower patch offering variable reward levels, and then search for food at the site in the absence of reward and after a long foraging pause. At the time of training, we presented the bees with a decrease in reward level or, instead, with either a small or a large increase in reward level. Testing took place as soon as they visited the patch on the day following training, when we measured the bees' food-searching behaviours. We found that the bees that had experienced increasing reward levels searched for food more persistently than the bees that had experienced decreasing reward levels, and that the bees that had experienced a large increase in reward level searched for food more persistently than the bees that had experienced a small increase in reward level. Because these differences at the time of testing cannot be accounted for by the bees' previous crop loads and food-intake rates, our results unambiguously demonstrate that honeybees adjust their investment of time/energy during foraging in relation to both the sign and the magnitude of past variations in the level of reward. It is likely that such variations lead to the formation of reward expectations enhancing a forager's reliance on a feeding site. Ultimately, this would make it more likely for honeybees to find food when forage is scarce.

  7. Magnitude and Recurrence of Submarine Landslides: Active vs. Passive Margins

    NASA Astrophysics Data System (ADS)

    Urgeles, Roger; Camerlenghi, Angelo

    2016-04-01

    Submarine landslides are ubiquitous along Mediterranean continental margins. With the aim of understanding mass-wasting processes and related hazard at the scale of a large marine basin encompassing multiple geological settings, we have compiled data on their geometry, age, and trigger mechanism with a geographic information system. The distribution of submarine landslides in the Mediterranean reveals that major deltaic wedges have a higher density of large submarine landslides, while tectonically active margins are characterized by relatively small failures. In all areas, landslide size distributions display power law scaling for landslides > 1 km3. We find consistent differences on the exponent of the power law (θ) depending on the tectonic setting. Active margins present steep slopes of the frequency-magnitude relationship while passive margins tend to display gentler slopes. This pattern likely responds to the common view that tectonically active margins have numerous but small failures, while passive margins have larger but fewer failures. Available age information suggests that failures exceeding 1000 km3 are infrequent and may recur every ~40 kyr. Smaller failures that can still cause significant damage might be relatively frequent (failures > 1 km3 may recur every 40 years). The database highlights that our knowledge of submarine landslide activity with time is limited to a few tens of thousands of years. Available data suggest that submarine landslides may preferentially occur during lowstand periods, but no firm conclusion can be made on this respect, as only 70 landslides (out of 696 in the database) have relatively accurate age determinations. The temporal pattern and changes in frequency-magnitude distribution suggest that sedimentation patterns and pore pressure development have had a major role in triggering slope failures and control the sediment flux from mass wasting to the deep basin.

  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

    2015-02-20

    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. © 2015 ARVO.

  10. The Absolute Magnitude of RRc Variables from Statistical Parallax

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

    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 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 V, RRab = 0.76 ± 0.12) and the only direct measurement of an RRc absolute magnitude (RZ Cephei, M V, RRc = 0.27 ± 0.17). We find the bulk velocity of the halo relative to the Sun to be (W π, W θ, Wz ) = (12.0, -209.9, 3.0) km s-1 in the radial, rotational, and vertical directions with dispersions (\\sigma _{W_\\pi }, \\sigma _{W_\\theta }, \\sigma _{W_z}) = (150.4, 106.1, 96.0) \\, km\\, s^{-1}. For the disk, we find (W π, W θ, Wz ) = (13.0, -42.0, -27.3) km s-1 relative to the Sun with dispersions (\\sigma _{W_\\pi }, \\sigma _{W_\\theta }, \\sigma _{W_z}) = (67.7,59.2,54.9) \\, km\\, s^{-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.

  11. 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

  12. Is order the defining feature of magnitude representation? An ERP study on learning numerical magnitude and spatial order of artificial symbols.

    PubMed

    Zhao, Hui; Chen, Chuansheng; Zhang, Hongchuan; Zhou, Xinlin; Mei, Leilei; Chen, Chunhui; Chen, Lan; Cao, Zhongyu; Dong, Qi

    2012-01-01

    Using an artificial-number learning paradigm and the ERP technique, the present study investigated neural mechanisms involved in the learning of magnitude and spatial order. 54 college students were divided into 2 groups matched in age, gender, and school major. One group was asked to learn the associations between magnitude (dot patterns) and the meaningless Gibson symbols, and the other group learned the associations between spatial order (horizontal positions on the screen) and the same set of symbols. Results revealed differentiated neural mechanisms underlying the learning processes of symbolic magnitude and spatial order. Compared to magnitude learning, spatial-order learning showed a later and reversed distance effect. Furthermore, an analysis of the order-priming effect showed that order was not inherent to the learning of magnitude. Results of this study showed a dissociation between magnitude and order, which supports the numerosity code hypothesis of mental representations of magnitude.

  13. Is Order the Defining Feature of Magnitude Representation? An ERP Study on Learning Numerical Magnitude and Spatial Order of Artificial Symbols

    PubMed Central

    Zhao, Hui; Chen, Chuansheng; Zhang, Hongchuan; Zhou, Xinlin; Mei, Leilei; Chen, Chunhui; Chen, Lan; Cao, Zhongyu; Dong, Qi

    2012-01-01

    Using an artificial-number learning paradigm and the ERP technique, the present study investigated neural mechanisms involved in the learning of magnitude and spatial order. 54 college students were divided into 2 groups matched in age, gender, and school major. One group was asked to learn the associations between magnitude (dot patterns) and the meaningless Gibson symbols, and the other group learned the associations between spatial order (horizontal positions on the screen) and the same set of symbols. Results revealed differentiated neural mechanisms underlying the learning processes of symbolic magnitude and spatial order. Compared to magnitude learning, spatial-order learning showed a later and reversed distance effect. Furthermore, an analysis of the order-priming effect showed that order was not inherent to the learning of magnitude. Results of this study showed a dissociation between magnitude and order, which supports the numerosity code hypothesis of mental representations of magnitude. PMID:23185363

  14. Atmospheric acoustic propagation: Characterization of magnitude and phase variability

    NASA Astrophysics Data System (ADS)

    Norris, David Earl

    This thesis explores the effects of atmospheric turbulence on the variability of propagated acoustic signals. Spatially distributed acoustic and turbulence measurements were made at sixteen frequencies under 600 Hz for both upwind and downwind propagation at ranges of 150 and 200 m, respectively. Observations were collected in convectively neutral and strong wind conditions. From the distributed measurements, ray angles of arrival were calculated. The arrival angles were consistent with direct, upward refracted rays for upwind propagation and direct/ground-reflected, downward refracted rays for downwind propagation. In the downwind case, the arrival angles displayed significant variability at the lower frequencies, possibly due to the presence of a ground wave. Predictions from eigenrays traced through mean wind and temperature profiles agreed well with downwind observations at the higher frequencies. The received complex acoustic signal at each source frequency was recovered by applying a standard Hilbert transform technique. Magnitude and phase fluctuations were calculated and compared to predictions from a scattering model restricted to the inertial subrange of atmospheric turbulence. The measured log-amplitude variances were in excellent agreement with predictions, suggesting that atmospheric length scales of order 1 m most influenced the variability of the signal's magnitude. Phase fluctuations that exhibited strong correlation across frequency were transformed into travel-time fluctuations. The travel-time fluctuations were found to be insensitive to minor path differences and strongly correlated with turbulent velocity fluctuations. The dominant length scales were interpreted to be of order 100 m. These correspond to the large-scale turbulent eddies in the convective boundary layer. A theoretical model based upon the two-dimensional turbulent energy spectrum was derived to predict the cross-correlation between travel-time fluctuations and velocity

  15. 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

  16. 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.

  17. Asteroid taxonomy and the H,G_{12} magnitude system

    NASA Astrophysics Data System (ADS)

    Oszkiewicz, D.; Bowell, E.; Wasserman, L.; Muinonen, K.; Penttilä, A.

    2014-07-01

    We review the asteroid magnitude systems. The conventionally used H,G system (approved by the IAU in 1985) was recently replaced by the H,G_{12} and H,G_1,G_2 systems (approved by the IAU in 2012). The new phase curves were already applied to a large quantity of photometric data (Oszkiewicz et al, 2011). In particular, absolute magnitudes and slope parameters were computed for about half a million asteroids and are publicly available through the Planetary Research Group (University of Helsinki) websites. Several correlations of the shape of the phase curves with asteroid physical parameters were also explored. In general, the steepness of a phase curve relates to the physical properties of an asteroid's surface such as for example composition, porosity, packing density, roughness, and grain size distribution. However, most of those cannot be studied with the currently available data. Some conclusions regarding links to albedo and taxonomy can still be made. First, the G_1 and G_2 parameters correlate with albedo. Generally, the higher the albedo the lower and higher are the G_1 and G_2 parameters, respectively. Second, the G_{12} parameter distributions for the different asteroid taxonomic complexes are statistically different. For example, the C-complex asteroids tend to have high G_{12}'s, S-complex asteroids low G_{12}'s, and objects from the X-complex lean towards average values (Oszkiewicz et al. 2012). Additionally, asteroid families with a few exceptions show homogeneity of the G_{12} parameter (Figure). This is yet another confirmation of homogeneity of asteroid families and therefore the overall tendency to retain the same physical properties across family members. We study the usability of the G_{12} parameter in topics such as breaking the X-complex degeneracy and taxonomical classification. In particular, we combine the G_{12}'s with the Sloan Digital Sky Survey (SDSS) and the Wide-Field Infrared Survey Explorer (WISE) data (Oszkiewicz et al. 2014) to

  18. 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

  19. 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

  20. Maternal mortality in Giza, Egypt: magnitude, causes, and prevention.

    PubMed

    Kane, T T; el-Kady, A A; Saleh, S; Hage, M; Stanback, J; Potter, L

    1992-01-01

    This article presents results from a population-based study of the magnitude and causes of maternal mortality in the Giza governorate of Egypt in 1985-86. Deaths to women in the reproductive ages were identified through the death registration system. Family members of the deceased were interviewed using the "verbal autopsy" approach. Immediate and underlying causes of death were then assessed by a medical panel. This methodology allows for the classification of multiple causes of death and is appropriate when registration of adult deaths is nearly complete, but reporting on cause of death on death certificates is poor. Of all reproductive-age deaths, 19 percent were maternal deaths. The maternal mortality ratio for Giza is estimated to be, at minimum, 126 maternal deaths per 100,000 live births. The maternal mortality rate is estimated to be, at minimum, 22 maternal deaths per 100,000 women aged 15-49, over 100 times the rate in Sweden. An average of 2.3 causes per maternal death were reported; the most common causes were postpartum hemorrhage (31 percent of cases) and hypertensive diseases of pregnancy, such as toxemia and eclampsia (28 percent of cases). Women experiencing hemorrhage, hypertensive diseases of pregnancy, or other serious complications must have easy access to hospital and maternity centers equipped for handling these conditions. Since most deliveries occur at home, many with the help of traditional birth attendants, TBAs will need training in early diagnosis, treatment, and/or effective referral of problem pregnancies.

  1. Injuries associated with teacher assaults: magnitude, nature, cost, and outcome.

    PubMed

    Levin, Pamela F; Martinez, Michelle Quigley; Walcott-McQuigg, Jacqueline; Chen, Shu Pi; Amman, Mary; Guenette, Caroline

    2006-05-01

    The purpose of this retrospective study was to describe the magnitude, nature, and costs of assault injuries among teachers, a high-risk group. Review of assault cases (N = 341) was based on internal and case management vendor records. The 3-year assault rate was 3.24 per 1,000 teachers. Assaults were predominately physical, occurring during classroom disputes and while restraining students. Assaults accounted for 2,480 lost workdays and more than dollars 714,000 in lost wages and case management fees. The most costly injuries on a per-case basis were strain-sprain injuries resulting in lost workdays and fractures not resulting in lost workdays. Less than 20% of the assaults accounted for all of the lost workdays and most of the case costs. Study variables accounted for 13% of case costs. Occupational health nurses should collaborate with school personnel, administrators, and parents to develop prevention programs, which may include de-escalation techniques for teachers as well as case management strategies.

  2. Magnitude of negative interpretation bias depends on severity of depression.

    PubMed

    Lee, Jong-Sun; Mathews, Andrew; Shergill, Sukhi; Yiend, Jenny

    2016-08-01

    The present study investigated the hypothesis that the magnitude of negative interpretation bias displayed by those with depression is related to the degree of depression they experience. Seventy one depressed participants (scoring 14 and above on the Beck Depression Inventory II) completed tasks spanning three domains of possible negative interpretations: semantic ambiguity; nonverbal ambiguity and situational ambiguity. Regression analyses revealed that just under half of the variance in depressive symptom severity was explained by the combination of negative interpretation bias tasks, with the strongest predictor of depressive symptom severity being negative interpretation of semantic ambiguity when reading ambiguous text descriptions. Subsidiary group analyses confirmed that severely depressed individuals interpreted emotionally ambiguous information in a more negative way than did their mildly or moderately depressed counterparts. These findings indicate that the degree of negative interpretive bias is closely related to depression severity and that bias manifests especially strongly at the most severe levels of depression. Our findings may help us to refine cognitive theories of depression and be helpful in guiding therapy.

  3. THE AGE OF ELLIPTICALS AND THE COLOR-MAGNITUDE RELATION

    SciTech Connect

    Schombert, James; Rakos, Karl E-mail: karl.rakos@chello.at

    2009-07-10

    Using new narrowband color observations of early-type galaxies in clusters, we reconstruct the color-magnitude relation (CMR) with a higher degree of accuracy than previous work. We then use the spectroscopically determined ages and metallicities from three samples, combined with multimetallicity spectral energy distribution models, to compare predicted colors for galaxies with young ages (less than 8 Gyr) with the known CMR. We find that the CMR cannot by reproduced by the spectroscopically determined ages and metallicities in any of the samples despite the high internal accuracies to the spectroscopic indices. In contrast, using only the (Fe) index to determine [Fe/H], and assuming a mean age of 12 Gyr for a galaxy's stellar population, we derive colors that exactly match not only the color zero point of the CMR but also its slope. We consider the source of young age estimates, the H{beta} index, and examine the conflict between red continuum colors and large H{beta} values in galaxy spectra. We conclude that our current understanding of stellar populations is insufficient to correctly interpret H{beta} values.

  4. Differences Between Magnitudes and Health Impacts of BC ...

    EPA Pesticide Factsheets

    Recent assessments have analyzed the health impacts of PM2.5 from emissions from different locations and sectors using simplified or reduced-form air quality models. Here we present an alternative approach using the adjoint of the Community Multiscale Air Quality (CMAQ) model, which provides source–receptor relationships at highly resolved sectoral, spatial, and temporal scales. While damage resulting from anthropogenic emissions of BC is strongly correlated with population and premature death, we found little correlation between damage and emission magnitude, suggesting that controls on the largest emissions may not be the most efficient means of reducing damage resulting from anthropogenic BC emissions. Rather, the best proxy for locations with damaging BC emissions is locations where premature deaths occur. Onroad diesel and nonroad vehicle emissions are the largest contributors to premature deaths attributed to exposure to BC, while onroad gasoline emissions cause the highest deaths per amount emitted. Emissions in fall and winter contribute to more premature deaths (and more per amount emitted) than emissions in spring and summer. Overall, these results show the value of the high-resolution source attribution for determining the locations, seasons, and sectors for which BC emission controls have the most effective health benefits. The National Exposure Research Laboratory’s Atmospheric Modeling Division (AMAD) conducts research in support of EPA’s mis

  5. 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.

  6. 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.

  7. Techniques for estimating magnitude and frequency of floods in Minnesota

    USGS Publications Warehouse

    Guetzkow, Lowell C.

    1977-01-01

     Estimating relations have been developed to provide engineers and designers with improved techniques for defining flow-frequency characteristics to satisfy hydraulic planning and design requirements. The magnitude and frequency of floods up to the 100-year recurrence interval can be determined for most streams in Minnesota by methods presented. By multiple regression analysis, equations have been developed for estimating flood-frequency relations at ungaged sites on natural flow streams. Eight distinct hydrologic regions are delineated within the State with boundaries defined generally by river basin divides. Regression equations are provided for each region which relate selected frequency floods to significant basin parameters. For main-stem streams, graphs are presented showing floods for selected recurrence intervals plotted against contributing drainage area. Flow-frequency estimates for intervening sites along the Minnesota River, Mississippi River, and the Red River of the North can be derived from these graphs. Flood-frequency characteristics are tabulated for 201 paging stations having 10 or more years of record.

  8. Spatial Model of Sky Brightness Magnitude in Langkawi Island, Malaysia

    NASA Astrophysics Data System (ADS)

    Redzuan Tahar, Mohammad; Kamarudin, Farahana; Umar, Roslan; Khairul Amri Kamarudin, Mohd; Sabri, Nor Hazmin; Ahmad, Karzaman; Rahim, Sobri Abdul; Sharul Aikal Baharim, Mohd

    2017-03-01

    Sky brightness is an essential topic in the field of astronomy, especially for optical astronomical observations that need very clear and dark sky conditions. This study presents the spatial model of sky brightness magnitude in Langkawi Island, Malaysia. Two types of Sky Quality Meter (SQM) manufactured by Unihedron are used to measure the sky brightness on a moonless night (or when the Moon is below the horizon), when the sky is cloudless and the locations are at least 100 m from the nearest light source. The selected locations are marked by their GPS coordinates. The sky brightness data obtained in this study were interpolated and analyzed using a Geographic Information System (GIS), thus producing a spatial model of sky brightness that clearly shows the dark and bright sky areas in Langkawi Island. Surprisingly, our results show the existence of a few dark sites nearby areas of high human activity. The sky brightness of 21.45 mag arcsec{}-2 in the Johnson-Cousins V-band, as the average of sky brightness equivalent to 2.8 × {10}-4{cd} {{{m}}}-2 over the entire island, is an indication that the island is, overall, still relatively dark. However, the amount of development taking place might reduce the number in the near future as the island is famous as a holiday destination.

  9. First measurement of σ8 using supernova magnitudes only

    NASA Astrophysics Data System (ADS)

    Castro, Tiago; Quartin, Miguel

    2014-09-01

    A method was recently proposed which allows the conversion of the weak-lensing effects in the Type Ia supernova (SNeIa) Hubble diagram from noise into signal. Such signal is sensitive to the growth of structure in the universe, and in particular can be used as a measurement of σ8 independently from more traditional methods such as those based on the cosmic microwave background, cosmic shear or cluster abundance. We extend here that analysis to allow for intrinsic non-Gaussianities in the supernova probability distribution function, and discuss how this can be best modelled using the Bayes factor. Although it was shown that a precise measurement of σ8 requires ˜105 SNeIa, current data already allow an important proof of principle. In particular, we make use of the 706 supernovae with z ≤ 0.9 of the recent Joint Lightcurve Analysis catalogue and show that a simple treatment of intrinsic non-Gaussianities with a couple of nuisance parameters is enough for our method to yield the values σ _8 = 0.84^{+0.28}_{-0.65} or σ8 < 1.45 at a 2σ confidence level. This result is consistent with mock simulations and it is also in agreement with independent measurements and presents the first ever measurement of σ8 using SNeIa magnitudes alone.

  10. 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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. 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

  12. 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.

  13. Magnitude and distribution of trunk stresses in telecommunications engineers.

    PubMed Central

    Nicholson, A S; David, P R; Sheppard, N J

    1981-01-01

    The incidence of back injuries has been shown to be greater in occupations as heavy manual work than light manual work. To plan a programme aimed at reducing the incidence of back injuries in industry those workers at high risk of incurring handling accidents and back injuries need to be identified and a knowledge of the specific occupational factors causing such injuries sought. This has been achieved for telecommunications engineers using epidemiological and radio pressure pill methodologies. The results verify the correlation between the back injury rates and physical work stresses of different occupational groups. The magnitude and relative frequency of trunk stresses in hazardous tasks has been determined and compared with those with lower incidences of back disorders. The study has confirmed that in examining manual handling hazards in industrial male populations a critical value of truncal stress can be applied and used to determine the safety of occupational factors in relation to their potential causing or contributing to degenerative back diseases. PMID:7317300

  14. Spatial Model of Sky Brightness Magnitude in Langkawi Island, Malaysia

    NASA Astrophysics Data System (ADS)

    Redzuan Tahar, Mohammad; Kamarudin, Farahana; Umar, Roslan; Khairul Amri Kamarudin, Mohd; Hazmin Sabri, Nor; Ahmad, Karzaman; Rahim, Sobri Abdul; Sharul Aikal Baharim, Mohd

    2017-03-01

    Sky brightness is an essential topic in the field of astronomy, especially for optical astronomical observations that need very clear and dark sky conditions. This study presents the spatial model of sky brightness magnitude in Langkawi Island, Malaysia. Two types of Sky Quality Meter (SQM) manufactured by Unihedron are used to measure the sky brightness on a moonless night (or when the Moon is below the horizon), when the sky is cloudless and the locations are at least 100 m from the nearest light source. The selected locations are marked by their GPS coordinates. The sky brightness data obtained in this study were interpolated and analyzed using a Geographic Information System (GIS), thus producing a spatial model of sky brightness that clearly shows the dark and bright sky areas in Langkawi Island. Surprisingly, our results show the existence of a few dark sites nearby areas of high human activity. The sky brightness of 21.45 mag arcsec{}-2 in the Johnson-Cousins V-band, as the average of sky brightness equivalent to 2.8 × {10}-4{cd} {{{m}}}-2 over the entire island, is an indication that the island is, overall, still relatively dark. However, the amount of development taking place might reduce the number in the near future as the island is famous as a holiday destination.

  15. Magnitude Squared of Coherence to Detect Imaginary Movement

    NASA Astrophysics Data System (ADS)

    Santos Filho, Sady Antônio; Tierra-Criollo, Carlos Julio; Souza, Ana Paula; Silva Pinto, Marcos Antonio; Cunha Lima, Maria Luiza; Manzano, Gilberto Mastrocola

    2009-12-01

    This work investigates the Magnitude Squared of Coherence (MSC) for detection of Event Related Potentials (ERPs) related to left-hand index finger movement. Initially, ERP presence was examined in different brain areas. To accomplish that, 20 EEG channels were used, positioned according to the 10-20 international system. The grand average, resulting from 10 normal subjects showed, as expected, responses at frontal, central, and parietal areas, particularly evident at the central area (C3, C4, Cz). The MSC, applied to movement imagination related EEG signals, detected a consistent response in frequencies around 0.3-1 Hz (delta band), mainly at central area (C3, Cz, and C4). Ability differences in control imagination among subjects produced different detection performance. Some subjects needed up to 45 events for a detectable response, while for some others only 10 events proved sufficient. Some subjects also required two or three experimental sessions in order to achieve detectable responses. For one subject, response detection was not possible at all. However, due to brain plasticity, it is plausible to expect that training sessions (to practice movement imagination) improve signal-noise ratio and lead to better detection using MSC. Results are sufficiently encouraging as to suggest further exploration of MSC for future BCI application.

  16. Extremal Regions Detection Guided by Maxima of Gradient Magnitude.

    PubMed

    Faraji, Mehdi; Shanbehzadeh, Jamshid; Nasrollahi, Kamal; Moeslund, Thomas Baltzer

    2015-12-01

    A problem of computer vision applications is to detect regions of interest under different imaging conditions. The state-of-the-art maximally stable extremal regions (MSERs) detects affine covariant regions by applying all possible thresholds on the input image, and through three main steps including: (1) making a component tree of extremal regions' evolution; (2) obtaining region stability criterion; and (3) cleaning up. The MSER performs very well, but, it does not consider any information about the boundaries of the regions, which are important for detecting repeatable extremal regions. We have shown in this paper that employing prior information about boundaries of regions results in a novel region detector algorithm that not only outperforms MSER, but avoids the MSER's rather complicated steps of enumeration and the cleaning up. To employ the information about the region boundaries, we introduce maxima of gradient magnitudes (MGMs) which are shown to be points that are mostly around the boundaries of the regions. Having found the MGMs, the method obtains a global criterion for each level of the input image which is used to find extremum levels (ELs). The found ELs are then used to detect extremal regions. The proposed algorithm which is called extremal regions of extremum levels (EREL) has been tested on the public benchmark data set of Mikolajczyk. The obtained experimental results show that the inclusion of region boundaries through MGMs, results in a detector that detects regions with high repeatability scores and is more robust against noise compared with MSER.

  17. Power tiller: vibration magnitudes and intervention development for vibration reduction.

    PubMed

    Chaturvedi, Varun; Kumar, Adarsh; Singh, J K

    2012-09-01

    The operators of power tiller are exposed to a high level of vibration originating from the dynamic interaction between the soil and the machine. The vibration from the power tiller is transmitted from the handle to hands, arms and shoulders. In the present study, experiments were conducted in three operational conditions i.e. transportation on farm roads, tilling with cultivator and rota-tilling with rota-vator. The highest vibration values were observed in x-direction in all the experiments. The maximum vibration rms values for x-direction were 5.96, 6.81 and 8.00 ms(-2) in tilling with cultivator, transportation and rota-tilling respectively. Three materials were used for intervention development to reduce vibration magnitude. The maximum reduction of 25.30, 31.21 and 30.45% in transportation; 23.50, 30.64 and 20.86% in tilling with cultivator and 24.03, 29.18 and 25.52% in rota-tilling were achieved with polyurethane (PU), rubber and combination of PU and rubber intervention. It was found that the maximum vibration reductions were achieved with the rubber in all three operational conditions. The average exposure time for occurrence of white finger syndrome increased by 28-50% with incorporation of intervention in different operations. Physiological and postural parameters also improved with incorporation of interventions. Copyright © 2012 Elsevier Ltd and The Ergonomics Society. All rights reserved.

  18. Magnitude of income-related disparities in adverse perinatal outcomes

    PubMed Central

    2014-01-01

    Background To assess and compare multiple measurements of socioeconomic position (SEP) in order to determine the relationship with adverse perinatal outcomes across various contexts. Methods A birth registry, the Nova Scotia Atlee Perinatal Database, was confidentially linked to income tax and related information for the year in which delivery occurred. Multiple logistic regression was used to examine odds ratios between multiple indicators of SEP and multiple adverse perinatal outcomes in 117734 singleton births between 1988 and 2003. Models for after tax family income were also adjusted for neighborhood deprivation to gauge the relative magnitude of effects related to SEP at both levels. Effects of SEP were stratified by single- versus multiple-parent family composition, and by urban versus rural location of residence. Results The risk of small for gestational age and spontaneous preterm birth was higher across all the indicators of lower SEP, while risk for large for gestational age was lower across indicators of lower SEP. Higher risk of postneonatal death was demonstrated for several measures of lower SEP. Higher material deprivation in the neighborhood of residence was associated with increased risk for perinatal death, small for gestational age birth, and iatrogenic and spontaneous preterm birth. Family composition and urbanicity were shown to modify the association between income and some perinatal outcomes. Conclusions This study highlights the importance of understanding the definitions of SEP and the mechanisms that lead to the association between income and poor perinatal outcomes, and broadening the types of SEP measures used in some cases. PMID:24589212

  19. 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

  20. Magnitude of head impact exposures in individual collegiate football players.

    PubMed

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

    2012-05-01

    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.

  1. Categorizing sources of risk and the estimated magnitude of risk.

    PubMed

    Aragonés, Juan Ignacio; Moyano, Emilio; Talayero, Fernando

    2008-05-01

    The social perception of risk is considered a multidimensional task, yet little attention has been paid to the cognitive components that organize sources of risk, despite their having been discovered in various research studies. This study attempts to concretely analyze the cultural dimension involved in those processes. In the first phase, we tried to discover to what extent sources of risk are organized into the same categories by people from different countries. In order to do so, two groups of participants were formed: 60 Spanish psychology students and 60 Chilean psychology students classified 43 sources of risk into different groups according to the criteria they found appropriate. The two samples classified risk into identical groups: acts of violence, drugs, electricity and home appliances, household chemicals, chemicals in the environment, public construction projects, transportation, sports, and natural disasters. In a second study, 100 Spanish and 84 Chilean students were asked to evaluate the magnitude of the damage incurred by 17 sources of risk. In both groups, it was observed that the evaluation of damage resulting from each source of risk was affected by its category.

  2. Velocity magnitude estimation with linear arrays using Doppler bandwidth.

    PubMed

    Tortoli, P; Guidi, G; Mantovani, L; Newhouse, V L

    2001-04-01

    The dependence of pulsed wave Doppler bandwidth on parameters typical of linear transducer arrays used in commercial Duplex and color flow mapping systems is investigated experimentally. For a single flow line it is observed that this bandwidth generally depends not only on the scatterer velocity and the beam-to-flow angle, but also on the flow line range and orientation. This is due to the fact that in Duplex and color flow systems the transducer is differently focused in the scan and elevation planes and its aperture and focal lengths are often made to vary, depending on the distance of the flow line from the transducer. It is however experimentally demonstrated that, at points where the ultrasound beamwidths in the scan and elevation planes are both comparable to the sample volume length, the Doppler bandwidth is independent of the beam-to-flow angle. It is also shown that this invariance can be extended to other ranges by appropriately modifying the array aperture. Finally, as an application of this independence, the flow-line velocity magnitude in these beam regions is estimated with better than 5% uncertainty through a simple bandwidth measurement.

  3. Interactive ultrasound image retrieval using magnitude frequency spectrum

    NASA Astrophysics Data System (ADS)

    Son, Jae Gon; Kim, Nam Chul; Chun, Young Deok; Park, Jun Hyo; Bae, Jun Ik

    2003-05-01

    An efficient algorithm is proposed for interactive ultrasound image retrieval using magnitude frequency spectrum (MFS). The interactive retrieval is especially intended to be useful for training an intern to diagnose with ultrasound images. In the retrieval process, information on which are relevant to a query image among object images retrieved in the previous iteration is fed back by user interaction. In order to improve discrimination between a query image and each of object images in a database (DB) by using the MFS, which is powerful for ultrasound image retrieval, we incorporate feature vector normalization and root filtering in feature extraction. To effectively integrate the feedback information, we use a feedback scheme based on Rocchio equation, where the feature of a query image is replaced with the weighted average of the feature of a query image and those of object images. Experimental results for real ultrasound images show that while yielding a precision of about 75% at a recall of about 8% in the initial retrieval, the interactive procedure yields a great performance improvement, that is, a precision of about 95% in the third iteration.

  4. 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.

  5. Near-infrared absolute magnitudes of Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Avelino, Arturo; Friedman, Andrew S.; Mandel, Kaisey; Kirshner, Robert; Challis, Peter

    2017-01-01

    Type Ia Supernovae light curves (SN Ia) in the near infrared (NIR) exhibit low dispersion in their peak luminosities and are less vulnerable to extinction by interstellar dust in their host galaxies. The increasing number of high quality NIR SNe Ia light curves, including the recent CfAIR2 sample obtained with PAIRITEL, provides updated evidence for their utility as standard candles for cosmology. Using NIR YJHKs light curves of ~150 nearby SNe Ia from the CfAIR2 and CSP samples, and from the literature, we determine the mean value and dispersion of the absolute magnitude in the range between -10 to 50 rest-frame days after the maximum luminosity in B band. We present the mean light-curve templates and Hubble diagram for YJHKs bands. This work contributes to a firm local anchor for supernova cosmology studies in the NIR which will help to reduce the systematic uncertainties due to host galaxy dust present in optical-only studies. This research is supported by NSF grants AST-156854, AST-1211196, Fundacion Mexico en Harvard, and CONACyT.

  6. 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.

  7. 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.

  8. The absolute magnitude distribution of cold classical Kuiper belt objects

    NASA Astrophysics Data System (ADS)

    Petit, Jean-Marc; Bannister, Michele T.; Alexandersen, Mike; Chen, Ying-Tung; Gladman, Brett; Gwyn, Stephen; Kavelaars, JJ; Volk, Kathryn

    2016-10-01

    We report measurements of the low inclination component of the main Kuiper Belt showing a size freqency distribution very steep for sizes larger than H_r ~ 6.5-7.0 and then a flattening to shallower slope that is still steeper than the collisional equilibrium slope.The Outer Solar System Origins Survey (OSSOS) is ongoing and is expected to detect over 500 TNOs in a precisely calibrated and characterized survey. Combining our current sample with CFEPS and the Alexandersen et al. (2015) survey, we analyse a sample of ~180 low inclination main classical (cold) TNOs, with absolute magnitude H_r (SDSS r' like flter) in the range 5 to 8.8. We confirm that the H_r distribution can be approximated by an exponential with a very steep slope (>1) at the bright end of the distribution, as has been recognized long ago. A transition to a shallower slope occurs around H_r ~ 6.5 - 7.0, an H_r mag identified by Fraster et al (2014). Faintward of this transition, we find a second exponential to be a good approximation at least until H_r ~ 8.5, but with a slope significantly steeper than the one proposed by Fraser et al. (2014) or even the collisional equilibrium value of 0.5.The transition in the cold TNO H_r distribution thus appears to occur at larger sizes than is observed in the high inclination main classical (hot) belt, an important indicator of a different cosmogony for these two sub-components of the main classical Kuiper belt. Given the largish slope faintward of the transition, the cold population with ~100 km diameter may dominate the mass of the Kuiper belt in the 40 AU < a < 47 au region.

  9. Landslide scaling and magnitude-frequency distribution (Invited)

    NASA Astrophysics Data System (ADS)

    Stark, C. P.; Guzzetti, F.

    2009-12-01

    Landslide-driven erosion is controlled by the scale and frequency of slope failures and by the consequent fluxes of debris off the hillslopes. Here I focus on the magnitude-frequency part of the process and develop a theory of initial slope failure and debris mobilization that reproduces the heavy-tailed distributions (PDFs) observed for landslide source areas and volumes. Landslide rupture propagation is treated as a quasi-static, non-inertial process of simplified elastoplastic deformation with strain weakening; debris runout is not considered. The model tracks the stochastically evolving imbalance of frictional, cohesive, and body forces across a failing slope, and uses safety-factor concepts to convert the evolving imbalance into a series of incremental rupture growth or arrest probabilities. A single rupture is simulated with a sequence of weighted ``coin tosses'' with weights set by the growth probabilities. Slope failure treated in this stochastic way is a survival process that generates asymptotically power-law-tail PDFs of area and volume for rock and debris slides; predicted scaling exponents are consistent with analyses of landslide inventories. The primary control on the shape of the model PDFs is the relative importance of cohesion over friction in setting slope stability: the scaling of smaller, shallower failures, and the size of the most common landslide volumes, are the result of the low cohesion of soil and regolith, whereas the negative power-law tail scaling for larger failures is tied to the greater cohesion of bedrock. The debris budget may be dominated by small or large landslides depending on the scaling of both the PDF and of the depth-length relation. I will present new model results that confirm the hypothesis that depth-length scaling is linear. Model PDF of landslide volumes.

  10. Magnitude of interfractional vaginal cuff movement: implications for external irradiation.

    PubMed

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

    2012-03-15

    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. 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. 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. 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. Copyright © 2012 Elsevier Inc. All rights reserved.

  11. 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

  12. [Early hypophosphataemia in at risk newborns. Frequency and magnitude].

    PubMed

    Bustos Lozano, Gerardo; Hidalgo Romero, Álvaro; Melgar Bonis, Ana; Ureta Velasco, Noelia; Orbea Gallardo, Carlos; Pallás Alonso, Carmen

    2017-06-03

    To determine the frequency and magnitude of neonatal hypophosphataemia (<4mg/dL) in a neonatal Intensive Care Unit and to describe risk groups. Retrospective study of hospitalised newborns over a 44 month period (phase 1). Retrospective study of <1,500g/<32 weeks of gestation newborns over a 6 month period (phase 2). Prospective study of <1,500g or 1,550-2,000g, and intrauterine growth restriction (IUGR) newborns. Measurements were made on the 1st, 3rd, 7th, and 14th days of life (phase 3). Phase 1: 34 (2.4%) of 1,394 patients had a diagnosis of hypophosphataemia, 76% of them ≤32 weeks of gestation and <1500 grams, and 24% >32 weeks with weight

  13. 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.

  14. Does Severity of Depression Predict Magnitude of Productivity Loss?

    PubMed Central

    Beck, Arne; Crain, A. Lauren; Solberg, Leif I.; Unützer, Jürgen; Glasgow, Russell E.; Maciosek, Michael V.; Whitebird, Robin

    2014-01-01

    PURPOSE Depression is associated with lowered work functioning, including absence, productivity impairment, and decreased job retention. However, few studies have examined depression symptoms across a continuum of severity in relationship to the magnitude of work impairment in a large and heterogeneous patient population. This study assessed the relationship between depression symptom severity and productivity loss among patients initiated on antidepressants. METHODS Data were obtained from patients participating in the DIAMOND Initiative (Depression Improvement Across Minnesota: Offering a New Direction), a statewide quality improvement collaborative to provide enhanced depression care. Patients newly started on antidepressants were surveyed with the Patient Health Questionnaire (PHQ-9), a measure of depression symptom severity, the Work Productivity and Activity Impairment questionnaire (WPAI) a measure of productivity loss, and items on health status and demographics. RESULTS We analyzed data from the 771 patients who reported current employment. General linear models adjusting for demographics and health status showed a significant linear, monotonic relationship between depression symptom severity and productivity loss (p<.0001). Even minor levels of depression symptoms were associated with decrements in work function. Greater productivity loss also was associated with full-time vs. part-time employment status (p<.001), fair or poor health (p=.05), and “not coupled” marital status (p=.07). CONCLUSIONS This study illustrated the relationship between the severity of depression symptoms and work function, suggesting that even minor levels of depression are associated with productivity loss. Employers may find it beneficial to invest in effective treatments for employees across the continuum of depression severity. PMID:25295792

  15. China's urbanization: magnitudes, social-economic causes and ecological consequences

    NASA Astrophysics Data System (ADS)

    Pan, S.; Tian, H.; Liu, M.; Liu, J.

    2006-05-01

    China, the third largest country of the world, is in transition from a largely rural society to a predominantly urban one. The Chinese urban system has experienced dramatic growth since the economic reforms were introduced in late 1970s. Two decades ago, fewer than 20% of China's people lived in urban areas; today 36% of the population was classified as urban; and an estimated 80% will be as urban in 2030. By integrating GIS and remote sensing technologies, we have quantified and characterized the magnitude and patterns of urbanization across China for the time period from 1980 to 2000. Our analysis suggests that in the traditional agricultural zones in China, e.g., Huang-Huai-Hai Plains, Yangtze River Delta, Peril River Delta and Sichuan Basin, the urban and built-up areas increased by 1.76 million hectares, of which 0.82 million hectares are expansion of urban areas, an increase of 24.78% compared with 1990 at the national scale. The Yellow River Delta, Yangtze River Delta and Peril River Delta also showed an increase of build-up area by 63.9%, 66.2% and 83.0% respectively. By using an econometric model in conjunction with spatial data and census records, we also examined how population growth and economic development have affected China's urbanization in the past decades. By using DLEM (the Dynamic Land Ecosystem Model), we further examined the potential impacts of urbanization on net primary productivity, carbon storage and water yield in China during 1980-2000.

  16. 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. Copyright © 2014. Published by Elsevier Inc.

  17. Hippocampal vulnerability and subacute response following varied blast magnitudes.

    PubMed

    Sajja, Venkata Siva Sai Sujith; Ereifej, Evon S; VandeVord, Pamela J

    2014-06-06

    Clinical outcomes from blast neurotrauma are associated with higher order cognitive functions such as memory, problem solving skills and attention. Current literature is limited to a single overpressure exposure or repeated exposures at the same level of overpressure and is focused on the acute response (<3 days). In an attempt to expand the understanding of neuropathological and molecular changes of the subacute response (7 days post injury), we used an established rodent model of blast neurotrauma. Three pressure magnitudes (low, moderate and high) were used to evaluate molecular injury thresholds. Immunohistochemical analysis demonstrated increased cleaved caspase-3 levels and loss of neuronal population (NeuN+) within the hippocampus of all pressure groups. On the contrary, selective activation of microglia was observed in the low blast group. In addition, increased astrocytes (GFAP), membrane signal transduction protein (Map2k1) and calcium regulator mechanosensitive protein (Piezo 2) were observed in the moderate blast group. Results from gene expression analysis suggested ongoing neuroprotection, as brain-derived neurotrophic factor (BDNF), glial-derived neurotrophic factor (GDNF) and Mn and CuZn superoxide dismutases (SOD) all increased in the low and moderate blast groups. Ongoing neuroprotection was further supported by increased SOD levels observed in the moderate group using immunohistochemistry. The gene expression level of glutamate aspartate transporter (GLAST) was upregulated in the low, but downregulated in the high blast group, while no changes were found in the moderate group. Overall, the data shown here provides evidence of a diverse neuroprotective and glial response to various levels of blast exposure. This mechanistic role of neuroprotection is vital in understanding ongoing cellular stress, both at the gene and protein levels, in order to develop interventional studies for the prognosis of injury. Copyright © 2014 Elsevier Ireland Ltd. All

  18. Denitrification in upland of China: Magnitude and influencing factors

    NASA Astrophysics Data System (ADS)

    Wang, Jinyang; Yan, Xiaoyuan

    2016-12-01

    A better understanding of influencing factors and accurate estimate of soil denitrification is a global concern. Here we present a synthesis of 300 observations of denitrification in Chinese upland soils from 39 field and laboratory studies using the acetylene inhibition technique. The results of a linear mixed model analysis showed that the rates of soil denitrification were significantly affected by crop type, soil organic carbon, soil pH, the measurement period, and the rate of N application. The emission factor (EF) and N2O/(N2O + N2) ratio for soil denitrification were on average 2.11 ± 0.17% and 0.508 ± 0.020, respectively. Our meta-analysis indicated that N fertilization increased soil denitrification by 311% (95% CI: 279-346%) and 112% (95% CI: 66-171%) in the field and laboratory studies, respectively. Substantial interactive effects between soil properties and N fertilization on soil denitrification were found. Although the highest values of both the rate of denitrification and the EF were found in vegetable fields, the size of the stimulating effect of N fertilization on soil denitrification was lower in vegetable fields than in maize and wheat fields. These results suggest that the crop-specific effect is important and that vegetable fields are potential hot spots of denitrification in Chinese uplands. Based on either the EF or the N2O/(N2O + N2) ratio obtained, the estimated amount of total denitrification from the upland soils was an order of magnitude lower than that from budget calculations, suggesting that the acetylene inhibition technique may significantly underestimate denitrification in Chinese upland soils.

  19. Magnitude and Frequency of Floods in New York

    USGS Publications Warehouse

    Lumia, Richard; Freehafer, Douglas A.; Smith, Martyn J.

    2006-01-01

    Techniques are presented for estimating the magnitude and frequency of flood discharges on rural, unregulated streams in New York, excluding Long Island. Peak-discharge-frequency data and basin characteristics from 388 streamflow-gaging stations in New York and adjacent states were used to develop multiple linear regression equations for flood discharges with recurrence intervals ranging from 1.25 to 500 years. A generalized least-squares (GLS) procedure was used to develop the regression equations. Separate sets of equations were developed for each of six hydrologic regions of New York; standard errors of prediction range from 14 to 43 percent. Statistically significant explanatory variables in the regression equations include drainage area, main-channel slope, percent basin storage, mean annual precipitation, percent forested area, a basin lag factor, a ratio of main-channel slope to basin slope, mean annual runoff, maximum snow depth, and percentage of basin above 1,200 feet. Drainage areas for the 388 sites used in the analyses ranged from 0.41 to 4,773 square miles. Methods of computing flood discharges from the regression equations differ, depending on whether the estimate is for a gaged or ungaged basin, and whether the basin crosses hydrologic-region or state boundaries. Examples of computations are included. Discharge-frequency estimates for an additional 122 streamflow-gaging stations with significant regulation or urbanization (including Long Island) are also included as at-site estimates. Basin characteristics, log-Pearson Type III statistics, and regression and weighted estimates of the discharge-frequency relations are tabulated for the streamflow-gaging stations used in the regression analyses. Sensitivity analyses showed that mean-annual precipitation, drainage area, mean annual runoff, and maximum snow depth are the variables to which computed discharges are most sensitive in the regression equations. Included with the report is a DVD that provides

  20. Maximum Earthquake Magnitude Assessments by Japanese Government Committees (Invited)

    NASA Astrophysics Data System (ADS)

    Satake, K.

    2013-12-01

    earthquakes. The Nuclear Regulation Authority, established in 2012, makes independent decisions based on the latest scientific knowledge. They assigned maximum credible earthquake magnitude of 9.6 for Nankai an Ryukyu troughs, 9.6 for Kuirl-Japan trench, and 9.2 for Izu-Bonin trench.

  1. 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.

  2. 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

  3. Pain from the life cycle perspective: Evaluation and Measurement through psychophysical methods of category estimation and magnitude estimation.

    PubMed

    Sousa, Fátima Aparecida Emm Faleiros; Silva, Talita de Cássia Raminelli da; Siqueira, Hilze Benigno de Oliveira Moura; Saltareli, Simone; Gomez, Rodrigo Ramon Falconi; Hortense, Priscilla

    2016-08-18

    to describe acute and chronic pain from the perspective of the life cycle. participants: 861 people in pain. The Multidimensional Pain Evaluation Scale (MPES) was used. in the category estimation method the highest descriptors of chronic pain for children/ adolescents were "Annoying" and for adults "Uncomfortable". The highest descriptors of acute pain for children/adolescents was "Complicated"; and for adults was "Unbearable". In magnitude estimation method, the highest descriptors of chronic pain was "Desperate" and for descriptors of acute pain was "Terrible". the MPES is a reliable scale it can be applied during different stages of development. descrever a dor aguda e a crônica na perspectiva do ciclo vital. Métodos: participaram 861 pessoas com dor. Foi utilizada a Escala Multidimensional de Avaliação da Dor (EMADOR). Resultados: no método da estimação de categoria o descritor da dor crônica de maior atribuição para crianças e adolescentes foi "Chata" e para adultos foi "Desconfortável". Os descritores de maior atribuição para dor aguda em crianças e adolescentes foram "Complicada" e em adultos "Insuportável". No método de estimação de magnitude, o descritor de maior atribuição na dor crônica foi "Atormentadora" e na dor aguda foi "Terrível". a EMADOR é uma escala confiável e pode ser utilizada nas diferentes etapas do desenvolvimento humano. la descripción del dolor agudo y crónico desde las perspectiva del ciclo de vida. participaron 861 personas con dolor. Se utilizó la Escala Multidimensional de Evaluación del Dolor (EMEDOR). en el método de estimación de categoría el descriptor de dolor crónico más alto para niños y adolescentes fue de Molesto y para adultos fue Incómodo. Los descriptores mayores de dolor agudo para niños y adolescentes fueron Complejo y para adultos Insoportable. En el método de estimación de magnitud, el mayor descriptor de dolor crónico fueron Atormentador y el mayor de dolor agudo fue Terrible

  4. 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

  5. A Modified Magnitude System that Produces Well-Behaved Magnitudes, Colors, and Errors Even for Low Signal-to-Noise Ratio Measurements

    NASA Astrophysics Data System (ADS)

    Lupton, Robert H.; Gunn, James E.; Szalay, Alexander S.

    1999-09-01

    We describe a modification of the usual definition of astronomical magnitudes, replacing the usual logarithm with an inverse hyperbolic sine function; we call these modified magnitudes ``asinh magnitudes.'' For objects detected at signal-to-noise ratios of greater than about 5, our modified definition is essentially identical to the traditional one; for fainter objects (including those with a formally negative flux), our definition is well behaved, tending to a definite value with finite errors as the flux goes to zero. This new definition is especially useful when considering the colors of faint objects, as the difference of two ``asinh'' magnitudes measures the usual flux ratio for bright objects, while avoiding the problems caused by dividing two very uncertain values for faint objects. The Sloan Digital Sky Survey data products will use this scheme to express all magnitudes in their catalogs.

  6. 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…

  7. 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…

  8. 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... Aspects of Contracting for Construction 36.204 Disclosure of the magnitude of construction projects. Advance notices and solicitations shall state the magnitude of the requirement in terms of...

  9. Are numbers grounded in a general magnitude processing system? A functional neuroimaging meta-analysis.

    PubMed

    Sokolowski, H Moriah; Fias, Wim; Bosah Ononye, Chuka; Ansari, Daniel

    2017-01-22

    It is currently debated whether numbers are processed using a number-specific system or a general magnitude processing system, also used for non-numerical magnitudes such as physical size, duration, or luminance. Activation likelihood estimation (ALE) was used to conduct the first quantitative meta-analysis of 93 empirical neuroimaging papers examining neural activation during numerical and non-numerical magnitude processing. Foci were compiled to generate probabilistic maps of activation for non-numerical magnitudes (e.g. physical size), symbolic numerical magnitudes (e.g. Arabic digits), and nonsymbolic numerical magnitudes (e.g. dot arrays). Conjunction analyses revealed overlapping activation for symbolic, nonsymbolic and non-numerical magnitudes in frontal and parietal lobes. Contrast analyses revealed specific activation in the left superior parietal lobule for symbolic numerical magnitudes. In contrast, small regions in the bilateral precuneus were specifically activated for nonsymbolic numerical magnitudes. No regions in the parietal lobes were activated for non-numerical magnitudes that were not also activated for numerical magnitudes. Therefore, numbers are processed using both a generalized magnitude system and format specific number regions.

  10. 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... CONTRACTS Special Aspects of Contracting for Construction 836.204 Disclosure of the magnitude of... must identify the magnitude of a VA project in advance notices and solicitations in terms of one of...

  11. 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... CONTRACTS Special Aspects of Contracting for Construction 836.204 Disclosure of the magnitude of... must identify the magnitude of a VA project in advance notices and solicitations in terms of one of...

  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... Aspects of Contracting for Construction 36.204 Disclosure of the magnitude of construction projects. Advance notices and solicitations shall state the magnitude of the requirement in terms of...

  13. 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... Aspects of Contracting for Construction 36.204 Disclosure of the magnitude of construction projects. Advance notices and solicitations shall state the magnitude of the requirement in terms of...

  14. 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…

  15. 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…

  16. 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... CONTRACTS Special Aspects of Contracting for Construction 836.204 Disclosure of the magnitude of... must identify the magnitude of a VA project in advance notices and solicitations in terms of one of...

  17. 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... CONTRACTS Special Aspects of Contracting for Construction 836.204 Disclosure of the magnitude of... must identify the magnitude of a VA project in advance notices and solicitations in terms of one of...

  18. 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... Special Aspects of Contracting for Construction 436.204 Disclosure of the magnitude of construction..., inclusive of options, to best describe the magnitude of the solicitation....

  19. 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... Special Aspects of Contracting for Construction 436.204 Disclosure of the magnitude of construction..., inclusive of options, to best describe the magnitude of the solicitation....

  20. 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... Special Aspects of Contracting for Construction 436.204 Disclosure of the magnitude of construction..., inclusive of options, to best describe the magnitude of the solicitation....

  1. 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... CONTRACTS Special Aspects of Contracting for Construction 836.204 Disclosure of the magnitude of... must identify the magnitude of a VA project in advance notices and solicitations in terms of one of...

  2. 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... Special Aspects of Contracting for Construction 436.204 Disclosure of the magnitude of construction..., inclusive of options, to best describe the magnitude of the solicitation....

  3. 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... Aspects of Contracting for Construction 36.204 Disclosure of the magnitude of construction projects. Advance notices and solicitations shall state the magnitude of the requirement in terms of...

  4. 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... Aspects of Contracting for Construction 36.204 Disclosure of the magnitude of construction projects. Advance notices and solicitations shall state the magnitude of the requirement in terms of...

  5. 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... Special Aspects of Contracting for Construction 436.204 Disclosure of the magnitude of construction..., inclusive of options, to best describe the magnitude of the solicitation....

  6. 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…

  7. 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…

  8. 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.

  9. Effects of magnitude and magnitude predictability of postural perturbations on preparatory cortical activity in older adults with and without Parkinson's disease.

    PubMed

    Smith, Beth A; Jacobs, Jesse V; Horak, Fay B

    2012-10-01

    The goal of this study was to identify whether impaired cortical preparation may relate to impaired scaling of postural responses of people with Parkinson's disease (PD). We hypothesized that impaired scaling of postural responses in participants with PD would be associated with impaired set-dependent cortical activity in preparation for perturbations of predictable magnitudes. Participants performed postural responses to backward surface translations. We examined the effects of perturbation magnitude (predictable small vs. predictable large) and predictability of magnitude (predictable vs. unpredictable-in-magnitude) on postural responses (center-of-pressure (CoP) displacements) and on preparatory electroencephalographic (EEG) measures of contingent negative variation (CNV) and alpha and beta event-related desynchronization (ERD). Our results showed that unpredictability of perturbation magnitude, but not the magnitude of the perturbation itself, was associated with increased CNV amplitude at the CZ electrode in both groups. While control participants scaled their postural responses to the predicted magnitude of the perturbation, their condition-related changes in CoP displacements were not correlated with condition-related changes in EEG preparatory activity (CNV or ERD). In contrast, participants with PD did not scale their postural responses to the predicted magnitude of the perturbation, but they did demonstrate greater beta ERD in the condition of predictably small-magnitude perturbations and greater beta ERD than the control participants at the CZ electrode. In addition, increased beta ERD in PD was associated with decreased adaptability of postural responses, suggesting that preparatory cortical activity may have a more direct influence on postural response scaling for people with PD than for control participants.

  10. Investigating reinforcer magnitude and reinforcer delay: a contingency management analog study.

    PubMed

    Packer, Robert R; Howell, Donelle N; McPherson, Sterling; Roll, John M

    2012-08-01

    The influence of reinforcer magnitude and reinforcer delay on smoking abstinence was studied using an analog model of contingency management. Participants (N = 103, 74% men) visited our laboratory 3 times daily for 5 days and received money for providing a breath sample that indicated smoking abstinence (carbon monoxide level ≤6 parts per million). Using a factorial design, we assigned participants randomly to 1 of 4 groups that could earn a total of either $207.50 (high-magnitude condition) or $70.00 (low-magnitude condition), and received earnings either at each visit (no-delay condition) or in a single lump sum 1 week following the study (delay condition). High-magnitude reinforcement, regardless of delay, was associated with higher rates of abstinence than was low-magnitude reinforcement. High magnitude of reinforcement provided immediately but in incremental amounts was associated with longer intervals to relapse during treatment in comparison with high-magnitude reinforcement provided in a single lump sum after a delay. Low rates of responding in the low-magnitude conditions made interpretation of the impact of delay in those conditions difficult. These findings further demonstrate that high magnitude of reinforcement results in better outcomes than does low magnitude of reinforcement, and that a delay to reinforcement can be detrimental-even when a high magnitude of reinforcement is provided.

  11. Effect of Magnitude Estimation of Pleasantness and Intensity on fMRI Activation to Taste.

    PubMed

    Cerf-Ducastel, B; Haase, L; Murphy, C

    2012-03-01

    The goal of the present study was to investigate whether the psychophysical evaluation of taste stimuli using magnitude estimation influences the pattern of cortical activation observed with neuroimaging. That is, whether different brain areas are involved in the magnitude estimation of pleasantness relative to the magnitude estimation of intensity. fMRI was utilized to examine the patterns of cortical activation involved in magnitude estimation of pleasantness and intensity during hunger in response to taste stimuli. During scanning, subjects were administered taste stimuli orally and were asked to evaluate the perceived pleasantness or intensity using the general Labeled Magnitude Scale (Green 1996, Bartoshuk et al. 2004). Image analysis was conducted using AFNI. Magnitude estimation of intensity and pleasantness shared common activations in the insula, rolandic operculum, and the medio dorsal nucleus of the thalamus. Globally, magnitude estimation of pleasantness produced significantly more activation than magnitude estimation of intensity. Areas differentially activated during magnitude estimation of pleasantness versus intensity included, e.g., the insula, the anterior cingulate gyrus, and putamen; suggesting that different brain areas were recruited when subjects made magnitude estimates of intensity and pleasantness. These findings demonstrate significant differences in brain activation during magnitude estimation of intensity and pleasantness to taste stimuli. An appreciation for the complexity of brain response to taste stimuli may facilitate a clearer understanding of the neural mechanisms underlying eating behavior and over consumption.

  12. Evidence for distinct magnitude systems for symbolic and non-symbolic number.

    PubMed

    Sasanguie, Delphine; De Smedt, Bert; Reynvoet, Bert

    2017-01-01

    Cognitive models of magnitude representation are mostly based on the results of studies that use a magnitude comparison task. These studies show similar distance or ratio effects in symbolic (Arabic numerals) and non-symbolic (dot arrays) variants of the comparison task, suggesting a common abstract magnitude representation system for processing both symbolic and non-symbolic numerosities. Recently, however, it has been questioned whether the comparison task really indexes a magnitude representation. Alternatively, it has been hypothesized that there might be different representations of magnitude: an exact representation for symbolic magnitudes and an approximate representation for non-symbolic numerosities. To address the question whether distinct magnitude systems exist, we used an audio-visual matching paradigm in two experiments to explore the relationship between symbolic and non-symbolic magnitude processing. In Experiment 1, participants had to match visually and auditory presented numerical stimuli in different formats (digits, number words, dot arrays, tone sequences). In Experiment 2, they were instructed only to match the stimuli after processing the magnitude first. The data of our experiments show different results for non-symbolic and symbolic number and are difficult to reconcile with the existence of one abstract magnitude representation. Rather, they suggest the existence of two different systems for processing magnitude, i.e., an exact symbolic system next to an approximate non-symbolic system.

  13. One tamed at a time: A new approach for controlling continuous magnitudes in numerical comparison tasks.

    PubMed

    Salti, Moti; Katzin, Naama; Katzin, David; Leibovich, Tali; Henik, Avishai

    2016-07-20

    Non-symbolic stimuli (i.e., dot arrays) are commonly used to study numerical cognition. However, in addition to numerosity, non-symbolic stimuli entail continuous magnitudes (e.g., total surface area, convex-hull, etc.) that correlate with numerosity. Several methods for controlling for continuous magnitudes have been suggested, all with the same underlying rationale: disassociating numerosity from continuous magnitudes. However, the different continuous magnitudes do not fully correlate; therefore, it is impossible to disassociate them completely from numerosity. Moreover, relying on a specific continuous magnitude in order to create this disassociation may end up in increasing or decreasing numerosity saliency, pushing subjects to rely on it more or less, respectively. Here, we put forward a taxonomy depicting the relations between the different continuous magnitudes. We use this taxonomy to introduce a new method with a complimentary Matlab toolbox that allows disassociating numerosity from continuous magnitudes and equating the ratio of the continuous magnitudes to the ratio of the numerosity in order to balance the saliency of numerosity and continuous magnitudes. A dot array comparison experiment in the subitizing range showed the utility of this method. Equating different continuous magnitudes yielded different results. Importantly, equating the convex hull ratio to the numerical ratio resulted in similar interference of numerical and continuous magnitudes.

  14. Frequency-Magnitude Study Down To Magnitude -4.4 For Induced Seismicity Recorded At Mponeng Deep Gold Mine, South Africa

    NASA Astrophysics Data System (ADS)

    Kwiatek, G.; Plenkers, K.; Schorlemmer, D.; Nakatani, M.; Yabe, Y.; Dresen, G. H.

    2009-12-01

    We investigate the lower magnitude limits and frequency-magnitude characteristics of the microseismic catalogue recorded with a high-sensitivity seismic network at the Mponeng mine, South Africa (Nakatani et al., SSA 2008 Proceedings). The network, composed of one 3-component accelerometer (50Hz to 25kHz) and 8 acoustic-emission sensors (700Hz to 200kHz), is located at a depth of 3543m and covers the limited volume of approx. 300x300x300m. The 3-component accelerometer was used to estimate the moment magnitude for the limited number of 135 very well recorded events (Mw in the range from -4.1 to -0.3). We use the relation between the moment magnitude estimated from accelerometer data and moment magnitude calculated from acoustic emission sensors to extend the catalogue to lower magnitudes. The magnitude of completeness of selected spatio-temporal subsets of the catalogue was estimated for: (1) post-blasting activity during working days, located more than 80 m from the network and (2) an aftershock sequence of a MW 1.9 event that occurred ~30 m from our network. Both datasets follow the Gutenberg-Richter (GR) frequency-magnitude relationship with no visible deviation from self-similar behavior of seismicity between Mw -4.4 and -1.9 for the aftershock sequence and between -3.5 and -1.5 for the post-blasting dataset. We estimated the magnitude of completeness of selected subset as low as -4.3 for the aftershock sequence and -3.4 for the post-blasting activity. Differences in magnitude of completeness are attributed to location of recorded activity and site effects. We do not observe Type A activity as reported in Richardson and Jordan (BSSA, 2002) study. To test the results obtained by GR analyzes and to get better insights into the influence of location and site effects, we estimated the probability-based magnitude of completeness for the aftershock sequence following Schorlemmer and Woessner (BSSA, 2008) was estimated for the aftershock sequence. This study reveals

  15. Representation of abstract quantitative rules applied to spatial and numerical magnitudes in primate prefrontal cortex.

    PubMed

    Eiselt, Anne-Kathrin; Nieder, Andreas

    2013-04-24

    Processing quantity information based on abstract principles is central to intelligent behavior. Neural correlates of quantitative rule selectivity have been identified previously in the prefrontal cortex (PFC). However, whether individual neurons represent rules applied to multiple magnitude types is unknown. We recorded from PFC neurons while monkeys switched between "greater than/less than" rules applied to spatial and numerical magnitudes. A majority of rule-selective neurons responded only to the quantitative rules applied to one specific magnitude type. However, another population of neurons generalized the magnitude principle and represented the quantitative rules related to both magnitudes. This indicates that the primate brain uses rule-selective neurons specialized in guiding decisions related to a specific magnitude type only, as well as generalizing neurons that respond abstractly to the overarching concept "magnitude rules."

  16. Grasping numbers: evidence for automatic influence of numerical magnitude on grip aperture.

    PubMed

    Namdar, Gal; Tzelgov, Joseph; Algom, Daniel; Ganel, Tzvi

    2014-06-01

    Previous research has shown that the fingers' aperture during grasp is affected by the numerical values of numbers embedded in the grasped objects: Numerically larger digits lead to larger grip apertures than do numerically smaller digits during the initial stages of the grasp. The relationship between numerical magnitude and visuomotor control has been taken to support the idea of a common underlying neural system mediating the processing of magnitude and the computation of object size for motor control. The purpose of the present study was to test whether the effect of magnitude on motor preparation is automatic. During grasping, we asked participants to attend to the colors of the digit while ignoring numerical magnitude. The results showed that numerical magnitude affected grip aperture during the initial stages of the grasp, even when magnitude information was irrelevant to the task at hand. These findings suggest that magnitude affects grasping preparation in an automatic fashion.

  17. 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.

  18. 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

  19. Representations of numerical and non-numerical magnitude both contribute to mathematical competence in children.

    PubMed

    Lourenco, Stella F; Bonny, Justin W

    2016-05-04

    A growing body of evidence suggests that non-symbolic representations of number, which humans share with nonhuman animals, are functionally related to uniquely human mathematical thought. Other research suggesting that numerical and non-numerical magnitudes not only share analog format but also form part of a general magnitude system raises questions about whether the non-symbolic basis of mathematical thinking is unique to numerical magnitude. Here we examined this issue in 5- and 6-year-old children using comparison tasks of non-symbolic number arrays and cumulative area as well as standardized tests of math competence. One set of findings revealed that scores on both magnitude comparison tasks were modulated by ratio, consistent with shared analog format. Moreover, scores on these tasks were moderately correlated, suggesting overlap in the precision of numerical and non-numerical magnitudes, as expected under a general magnitude system. Another set of findings revealed that the precision of both types of magnitude contributed shared and unique variance to the same math measures (e.g. calculation and geometry), after accounting for age and verbal competence. These findings argue against an exclusive role for non-symbolic number in supporting early mathematical understanding. Moreover, they suggest that mathematical understanding may be rooted in a general system of magnitude representation that is not specific to numerical magnitude but that also encompasses non-numerical magnitude.

  20. 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.

  1. Effects of reinforcer consumption and magnitude on response rates during noncontingent reinforcement.

    PubMed

    Roscoe, Eileen M; Iwata, Brian A; Rand, Melissa S

    2003-01-01

    Results of previous research on the effects of noncontingent reinforcement (NCR) have been inconsistent when magnitude of reinforcement was manipulated. We attempted to clarify the influence of NCR magnitude by including additional controls. In Study 1, we examined the effects of reinforcer consumption time by comparing the same magnitude of NCR when session time was and was not corrected to account for reinforcer consumption. Lower response rates were observed when session time was not corrected, indicating that reinforcer consumption can suppress response rates. In Study 2, we first selected varying reinforcer magnitudes (small, medium, and large) on the basis of corrected response rates observed during a contingent reinforcement condition and then compared the effects of these magnitudes during NCR. One participant exhibited lower response rates when large-magnitude reinforcers were delivered; the other ceased responding altogether even when small-magnitude reinforcers were delivered. We also compared the effects of the same NCR magnitude (medium) during 10-min and 30-min sessions. Lower response rates were observed during 30-min sessions, indicating that the number of reinforcers consumed across a session can have the same effect as the number consumed per reinforcer delivery. These findings indicate that, even when response rate is corrected to account for reinforcer consumption, larger magnitudes of NCR (defined on either a per-delivery or per-session basis) result in lower response rates than do smaller magnitudes.

  2. Reinforcer magnitude and rate dependency: evaluation of resistance-to-change mechanisms.

    PubMed

    Pinkston, Jonathan W; Ginsburg, Brett C; Lamb, Richard J

    2014-10-01

    Under many circumstances, reinforcer magnitude appears to modulate the rate-dependent effects of drugs such that when schedules arrange for relatively larger reinforcer magnitudes rate dependency is attenuated compared with 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 FI 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; however, these effects were not modulated by reinforcer magnitude. In addition, 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 that a resistance-to-change interpretation of the effects of reinforcer magnitude on rate dependency is not viable.

  3. Defective number module or impaired access? Numerical magnitude processing in first graders with mathematical difficulties.

    PubMed

    De Smedt, Bert; Gilmore, Camilla K

    2011-02-01

    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 magnitude comparison task and an approximate addition task, which were presented in a symbolic and a nonsymbolic (dot arrays) format. Children with MLD and LA were impaired on tasks that involved the access of numerical magnitude information from symbolic representations, with the LA children showing a less severe performance pattern than children with MLD. They showed no deficits in accessing magnitude from underlying nonsymbolic magnitude representations. Our findings indicate that this performance pattern occurs in children from first grade onward and generalizes beyond numerical magnitude comparison tasks. These findings shed light on the types of intervention that may help children who struggle with learning mathematics.

  4. Statistics of Delta v magnitude for a trajectory correction maneuver containing deterministic and random components

    NASA Technical Reports Server (NTRS)

    Bollman, W. E.; Chadwick, C.

    1982-01-01

    A number of interplanetary missions now being planned involve placing deterministic maneuvers along the flight path to alter the trajectory. Lee and Boain (1973) examined the statistics of trajectory correction maneuver (TCM) magnitude with no deterministic ('bias') component. The Delta v vector magnitude statistics were generated for several values of random Delta v standard deviations using expansions in terms of infinite hypergeometric series. The present investigation uses a different technique (Monte Carlo simulation) to generate Delta v magnitude statistics for a wider selection of random Delta v standard deviations and also extends the analysis to the case of nonzero deterministic Delta v's. These Delta v magnitude statistics are plotted parametrically. The plots are useful in assisting the analyst in quickly answering questions about the statistics of Delta v magnitude for single TCM's consisting of both a deterministic and a random component. The plots provide quick insight into the nature of the Delta v magnitude distribution for the TCM.

  5. 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.

  6. Testing the shared spatial representation of magnitude of auditory and visual intensity.

    PubMed

    Fairhurst, Merle T; Deroy, Ophelia

    2017-03-01

    The largely automatic mapping observed between space and sensory magnitudes suggests representation by a single system across domains. Using stimulus response compatibility tasks, the study confirms that a relative, auditory magnitude such as loudness shows a spatial compatibility effect similar to those evidenced for visual sensory domains but only with comparison tasks and for vertically oriented responses. No effect is seen when participants track changes in amplitude or when responses are oriented vertically. In a bimodal context, the study tested whether the spatial mapping of magnitude in 1 sensory modality (loudness) interacts with the spatial representation of magnitude in another sense (luminance). Observed interactions across modalities suggest overlap of magnitude representation across distinct sensory domains, whereas the absence of an effect for dynamic changes in loudness suggests that it is useful for decisions to act on 1 of several objects rather than for tracking magnitude changes in 1 object. (PsycINFO Database Record

  7. On the effects of noncontingent delivery of differing magnitudes of reinforcement.

    PubMed

    Carr, J E; Bailey, J S; Ecott, C L; Lucker, K D; Weil, T M

    1998-01-01

    We conducted a parametric analysis of response suppression associated with different magnitudes of noncontingent reinforcement (NCR). Participants were 5 adults with severe or profound mental retardation who engaged in a manual response that was reinforced on variable-ratio schedules during baseline. Participants were then exposed to NCR via multielement and reversal designs. The fixed-time schedules were kept constant while the magnitude of the reinforcing stimulus was varied across three levels (low, medium, and high). Results showed that high-magnitude NCR schedules produced large and consistent reductions in response rates, medium-magnitude schedules produced less consistent and smaller reductions, and low-magnitude schedules produced little or no effect on responding. These results suggest that (a) NCR affects responding by altering an establishing operation (i.e., attenuating a deprivation state) rather than through extinction, and (b) magnitude of reinforcement is an important variable in determining the effectiveness of NCR.

  8. On the effects of noncontingent delivery of differing magnitudes of reinforcement.

    PubMed Central

    Carr, J E; Bailey, J S; Ecott, C L; Lucker, K D; Weil, T M

    1998-01-01

    We conducted a parametric analysis of response suppression associated with different magnitudes of noncontingent reinforcement (NCR). Participants were 5 adults with severe or profound mental retardation who engaged in a manual response that was reinforced on variable-ratio schedules during baseline. Participants were then exposed to NCR via multielement and reversal designs. The fixed-time schedules were kept constant while the magnitude of the reinforcing stimulus was varied across three levels (low, medium, and high). Results showed that high-magnitude NCR schedules produced large and consistent reductions in response rates, medium-magnitude schedules produced less consistent and smaller reductions, and low-magnitude schedules produced little or no effect on responding. These results suggest that (a) NCR affects responding by altering an establishing operation (i.e., attenuating a deprivation state) rather than through extinction, and (b) magnitude of reinforcement is an important variable in determining the effectiveness of NCR. PMID:9757577

  9. 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.

  10. 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.

  11. 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

  12. Adaptive Modulation Schemes for OFDM and SOQPSK Using Error Vector Magnitude (EVM) and Godard Dispersion

    DTIC Science & Technology

    2014-06-01

    Document Number: SET 2014-0039 412TW-PA-14271 Adaptive Modulation Schemes for OFDM and SOQPSK Using Error Vector Magnitude (EVM...4. TITLE AND SUBTITLE Adaptive Modulation Schemes for OFDM and SOQPSK Using Error Vector Magnitude (EVM) and Godard Dispersion 5a. CONTRACT NUMBER...multiplexing ( OFDM ) and shaped-offset quadrature phased-shift keying (SOQPSK). We present the error vector magnitude (EVM) for OFDM and second-order Godard

  13. Technique for estimating the magnitude and frequency of floods in the Houston, Texas, Metropolitan Area

    USGS Publications Warehouse

    Liscum, Fred; Massey, B.C.

    1980-01-01

    The relationships indicate that as a basin changes from a completely natural state to one of complete urbanization, the magnitude of a 2-year peak discharge is increased by a factor of 4.2, the magnitude of a 50-year peak is increased by a factor of 4.9, and the magnitude of a 100-year peak is increased by a factor of 4. 9.

  14. Acerca del moho

    EPA Pesticide Factsheets

    El moho forma parte del medio ambiente natural. Afuera del hogar, el moho juega un papel en la naturaleza al desintegrar materias organicas tales como las hojas que se han caido o los arboles muertos. El moho puede crecer adentro del hogar cuando las espor

  15. Are Earthquakes Predictable? A Study on Magnitude Correlations in Earthquake Catalog and Experimental Data

    NASA Astrophysics Data System (ADS)

    Stavrianaki, K.; Ross, G.; Sammonds, P. R.

    2015-12-01

    The clustering of earthquakes in time and space is widely accepted, however the existence of correlations in earthquake magnitudes is more questionable. In standard models of seismic activity, it is usually assumed that magnitudes are independent and therefore in principle unpredictable. Our work seeks to test this assumption by analysing magnitude correlation between earthquakes and their aftershocks. To separate mainshocks from aftershocks, we perform stochastic declustering based on the widely used Epidemic Type Aftershock Sequence (ETAS) model, which allows us to then compare the average magnitudes of aftershock sequences to that of their mainshock. The results of earthquake magnitude correlations were compared with acoustic emissions (AE) from laboratory analog experiments, as fracturing generates both AE at the laboratory scale and earthquakes on a crustal scale. Constant stress and constant strain rate experiments were done on Darley Dale sandstone under confining pressure to simulate depth of burial. Microcracking activity inside the rock volume was analyzed by the AE technique as a proxy for earthquakes. Applying the ETAS model to experimental data allowed us to validate our results and provide for the first time a holistic view on the correlation of earthquake magnitudes. Additionally we search the relationship between the conditional intensity estimates of the ETAS model and the earthquake magnitudes. A positive relation would suggest the existence of magnitude correlations. The aim of this study is to observe any trends of dependency between the magnitudes of aftershock earthquakes and the earthquakes that trigger them.

  16. 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.

  17. Relation between postural sway magnitude and metabolic energy cost during upright standing on a compliant surface.

    PubMed

    Houdijk, Han; Brown, Starr E; van Dieën, Jaap H

    2015-09-15

    Postural control performance is often described in terms of postural sway magnitude, assuming that lower sway magnitude reflects better performance. However, people do not typically minimize sway magnitude when performing a postural control task. Possibly, other criteria are satisfied when people select the amount of sway they do. Minimal metabolic cost has been suggested as such a criterion. The aim of this study was to experimentally test the relation between sway magnitude and metabolic cost to establish whether metabolic cost could be a potential optimization criterion in postural control. Nineteen healthy subjects engaged in two experiments in which different magnitudes of sway were evoked during upright standing on a foam surface while metabolic energy expenditure, center of pressure (CoP) excursion, and muscle activation were recorded. In one experiment, sway was manipulated by visual feedback of CoP excursion. The other experiment involved verbal instructions of standing still, natural or relaxed. In both experiments, metabolic cost changed with sway magnitude in an asymmetric parabolic fashion, with a minimum around self-selected sway magnitudes and a larger increase at small compared with large sway magnitudes. This metabolic response was paralleled by a change in tonic and phasic EMG activity in the major leg muscles. It is concluded that these results are in line with the notion that metabolic cost can be an optimization criterion used to set postural control and as such could account for the magnitude of naturally occurring postural sway in healthy individuals, although the pathway remains to be elucidated.

  18. A general magnitude system in human adults: Evidence from a subliminal priming paradigm.

    PubMed

    Lourenco, Stella F; Ayzenberg, Vladislav; Lyu, Jennifer

    2016-08-01

    Despite general agreement that number and other magnitudes share analog format, there is disagreement about the extent to which representations of numerical and non-numerical magnitude recruit common cognitive and neural resources. Cross-dimensional interactions between number and other magnitudes on Stroop-like tasks have been taken as evidence for integration across magnitudes, but such effects are subject to alternative interpretations that allow for differentiated representations. Here we use a subliminal priming paradigm to test for interactions between different magnitudes (number and area) when one magnitude is not consciously detectable. Across two experiments, we first provide evidence for the feasibility of this paradigm by demonstrating that transfer occurs within the dimension of number; that is, symbolic numerals (Arabic digits) that were subliminally primed affected judgments of non-symbolic numerosities in target displays. Crucially, we also found transfer across magnitudes-from subliminally primed numerals to target displays of cumulative surface area whether participants made an ordinal judgment (i.e., "which array is larger in area?") or judged whether two arrays were the same or different in area. These findings suggest that representations of number and area are not fully differentiated. Moreover, they provide unique support for a general magnitude system that includes direct connections, or overlap, between the neural codes for numerical and non-numerical magnitudes.

  19. 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.

  20. Quasi real-time estimation of the moment magnitude of large earthquake from static strain changes

    NASA Astrophysics Data System (ADS)

    Itaba, S.

    2016-12-01

    The 2011 Tohoku-Oki (off the Pacific coast of Tohoku) earthquake, of moment magnitude 9.0, was accompanied by large static strain changes (10-7), as measured by borehole strainmeters operated by the Geological Survey of Japan in the Tokai, Kii Peninsula, and Shikoku regions. A fault model for the earthquake on the boundary between the Pacific and North American plates, based on these borehole strainmeter data, yielded a moment magnitude of 8.7. On the other hand, based on the seismic wave, the prompt report of the magnitude which the Japan Meteorological Agency (JMA) announced just after earthquake occurrence was 7.9. Such geodetic moment magnitudes, derived from static strain changes, can be estimated almost as rapidly as determinations using seismic waves. I have to verify the validity of this method in some cases. In the case of this earthquake's largest aftershock, which occurred 29 minutes after the mainshock. The prompt report issued by JMA assigned this aftershock a magnitude of 7.3, whereas the moment magnitude derived from borehole strain data is 7.6, which is much closer to the actual moment magnitude of 7.7. In order to grasp the magnitude of a great earthquake earlier, several methods are now being suggested to reduce the earthquake disasters including tsunami. Our simple method of using static strain changes is one of the strong methods for rapid estimation of the magnitude of large earthquakes, and useful to improve the accuracy of Earthquake Early Warning.

  1. 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.

  2. Magnitude Estimation for the 2011 Tohoku-Oki Earthquake Based on Ground Motion Prediction Equations

    NASA Astrophysics Data System (ADS)

    Eshaghi, Attieh; Tiampo, Kristy F.; Ghofrani, Hadi; Atkinson, Gail M.

    2015-08-01

    This study investigates whether real-time strong ground motion data from seismic stations could have been used to provide an accurate estimate of the magnitude of the 2011 Tohoku-Oki earthquake in Japan. Ultimately, such an estimate could be used as input data for a tsunami forecast and would lead to more robust earthquake and tsunami early warning. We collected the strong motion accelerograms recorded by borehole and free-field (surface) Kiban Kyoshin network stations that registered this mega-thrust earthquake in order to perform an off-line test to estimate the magnitude based on ground motion prediction equations (GMPEs). GMPEs for peak ground acceleration and peak ground velocity (PGV) from a previous study by Eshaghi et al. in the Bulletin of the Seismological Society of America 103. (2013) derived using events with moment magnitude ( M) ≥ 5.0, 1998-2010, were used to estimate the magnitude of this event. We developed new GMPEs using a more complete database (1998-2011), which added only 1 year but approximately twice as much data to the initial catalog (including important large events), to improve the determination of attenuation parameters and magnitude scaling. These new GMPEs were used to estimate the magnitude of the Tohoku-Oki event. The estimates obtained were compared with real time magnitude estimates provided by the existing earthquake early warning system in Japan. Unlike the current operational magnitude estimation methods, our method did not saturate and can provide robust estimates of moment magnitude within ~100 s after earthquake onset for both catalogs. It was found that correcting for average shear-wave velocity in the uppermost 30 m () improved the accuracy of magnitude estimates from surface recordings, particularly for magnitude estimates of PGV (Mpgv). The new GMPEs also were used to estimate the magnitude of all earthquakes in the new catalog with at least 20 records. Results show that the magnitude estimate from PGV values using

  3. Rational numbers: componential versus holistic representation of fractions in a magnitude comparison task.

    PubMed

    Meert, Gaëlle; Grégoire, Jacques; Noël, Marie-Pascale

    2009-08-01

    This study investigated whether the mental representation of the fraction magnitude was componential and/or holistic in a numerical comparison task performed by adults. In Experiment 1, the comparison of fractions with common numerators (x/a_x/b) and of fractions with common denominators (a/x_b/x) primed the comparison of natural numbers. In Experiment 2, fillers (i.e., fractions without common components) were added to reduce the regularity of the stimuli. In both experiments, distance effects indicated that participants compared the numerators for a/x_b/x fractions, but that the magnitudes of the whole fractions were accessed and compared for x/a_x/b fractions. The priming effect of x/a_x/b fractions on natural numbers suggested that the interference of the denominator magnitude was controlled during the comparison of these fractions. These results suggested a hybrid representation of their magnitude (i.e., componential and holistic). In conclusion, the magnitude of the whole fraction can be accessed, probably by estimating the ratio between the magnitude of the denominator and the magnitude of the numerator. However, adults might prefer to rely on the magnitudes of the components and compare the magnitudes of the whole fractions only when the use of a componential strategy is made difficult.

  4. Maximum-magnitude estimation of the object's power spectrum in stellar speckle interferometry.

    PubMed

    Granrath, D J

    1984-11-01

    The maximum Fourier magnitude taken over a set of speckle images is proposed as a replacement for the standard power-spectrum average. This new statistic estimates the diffraction-limited object-times-telescope magnitude values in a statistically unbiased and sufficient fashion and has a variance that decreases with sample size faster than the average magnitude's variance. Simultaneous imaging of a nearby point source is unnecessary with this technique, and any object that lies within a single isoplanatic patch of the atmosphere can be estimated. Magnitude-estimation results of the double star Capella are shown to corroborate these claims.

  5. Tremor magnitude: a single index to assess writing and drawing in essential tremor.

    PubMed

    Ulmanová, Olga; Homann, Carl Nikolaus; Ulman, Radek; Jech, Robert; Capek, Václav; Klempír, Jirí; Růzicka, Evzen

    2007-05-01

    Hand tremor often causes disability in patients with essential tremor (ET). Aim of the study was to investigate whether tremor magnitude, a new single quantitative score obtained from digital tablet recordings of writing and drawing, is able to adequately reflect disability in ET patients. Mean tremor magnitude values showed significant difference between 14 ET patients and 14 healthy age matched controls (p<0.0001). The tremor magnitude values showed significant correlation with standard methods of clinical assessment (p<0.01). We present tremor magnitude as an index that reflects disability resulting from tremor and can help to evaluate ET.

  6. 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.

  7. Fast Moment Magnitude Determination from P-wave Trains for Bucharest Rapid Early Warning System (BREWS)

    NASA Astrophysics Data System (ADS)

    Lizurek, Grzegorz; Marmureanu, Alexandru; Wiszniowski, Jan

    2017-03-01

    Bucharest, with a population of approximately 2 million people, has suffered damage from earthquakes in the Vrancea seismic zone, which is located about 170 km from Bucharest, at a depth of 80-200 km. Consequently, an earthquake early warning system (Bucharest Rapid earthquake Early Warning System or BREWS) was constructed to provide some warning about impending shaking from large earthquakes in the Vrancea zone. In order to provide quick estimates of magnitude, seismic moment was first determined from P-waves and then a moment magnitude was determined from the moment. However, this magnitude may not be consistent with previous estimates of magnitude from the Romanian Seismic Network. This paper introduces the algorithm using P-wave spectral levels and compares them with catalog estimates. The testing procedure used waveforms from about 90 events with catalog magnitudes from 3.5 to 5.4. Corrections to the P-wave determined magnitudes according to dominant intermediate depth events mechanism were tested for November 22, 2014, M5.6 and October 17, M6 events. The corrections worked well, but unveiled overestimation of the average magnitude result of about 0.2 magnitude unit in the case of shallow depth event ( H < 60 km). The P-wave spectral approach allows for the relatively fast estimates of magnitude for use in BREWS. The average correction taking into account the most common focal mechanism for radiation pattern coefficient may lead to overestimation of the magnitude for shallow events of about 0.2 magnitude unit. However, in case of events of intermediate depth of M6 the resulting M w is underestimated at about 0.1-0.2. We conclude that our P-wave spectral approach is sufficiently robust for the needs of BREWS for both shallow and intermediate depth events.

  8. 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.

  9. Dealing with Big Numbers: Representation and Understanding of Magnitudes outside of Human Experience

    ERIC Educational Resources Information Center

    Resnick, Ilyse; Newcombe, Nora S.; Shipley, Thomas F.

    2017-01-01

    Being able to estimate quantity is important in everyday life and for success in the STEM disciplines. However, people have difficulty reasoning about magnitudes outside of human perception (e.g., nanoseconds, geologic time). This study examines patterns of estimation errors across temporal and spatial magnitudes at large scales. We evaluated the…

  10. Estimation of daily stream flow of southeastern coastal plain watersheds by combining estimated magnitude and sequence

    Treesearch

    Herbert Ssegane; Devendra M. Amatya; E.W. Tollner; Zhaohua Dai; Jami E. Nettles

    2013-01-01

    Commonly used methods to predict streamflow at ungauged watersheds implicitly predict streamflow magnitude and temporal sequence concurrently. An alternative approach that has not been fully explored is the conceptualization of streamflow as a composite of two separable components of magnitude and sequence, where each component is estimated separately and then combined...

  11. Differential processing of symbolic numerical magnitude and order in first-grade children.

    PubMed

    Vogel, Stephan E; Remark, Alicia; Ansari, Daniel

    2015-01-01

    A growing body of evidence has indicated a link between individual differences in children's symbolic numerical magnitude discrimination (e.g., judging which of two numbers is numerically larger) and their arithmetic achievement. In contrast, relatively little is known about the processing of numerical order (e.g., deciding whether two numbers are in ascending or descending numerical order) and whether individual differences in judging numerical order are related to the processing of numerical magnitude and arithmetic achievement. In view of this, we investigated the relationships among symbolic numerical magnitude comparison, symbolic order judgments, and mathematical achievement. Data were collected from a group of 61 first-grade children who completed a magnitude comparison task, an order judgment task, and two standardized tests of arithmetic achievement. Results indicated a numerical distance effect (NDE) in both the symbolic numerical magnitude discrimination and the numerical order judgment condition. However, correlation analyses demonstrated that although individual differences in magnitude comparison correlated significantly with arithmetic achievement, performance on the order judgment task did not. Moreover, the NDE of the magnitude and order comparison performance was also found to be uncorrelated. These findings suggest that order and numerical magnitude processing may be underpinned by different processes and relate differentially to arithmetic achievement in young children.

  12. 48 CFR 236.204 - Disclosure of the magnitude of construction projects.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 3 2012-10-01 2012-10-01 false Disclosure of the magnitude of construction projects. 236.204 Section 236.204 Federal Acquisition Regulations System DEFENSE... magnitude of construction projects. Additional price ranges are— (i) Between $10,000,000 and...

  13. 48 CFR 236.204 - Disclosure of the magnitude of construction projects.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 3 2013-10-01 2013-10-01 false Disclosure of the magnitude of construction projects. 236.204 Section 236.204 Federal Acquisition Regulations System DEFENSE... magnitude of construction projects. Additional price ranges are— (i) Between $10,000,000 and...

  14. 48 CFR 236.204 - Disclosure of the magnitude of construction projects.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 3 2014-10-01 2014-10-01 false Disclosure of the magnitude of construction projects. 236.204 Section 236.204 Federal Acquisition Regulations System DEFENSE... magnitude of construction projects. Additional price ranges are— (i) Between $10,000,000 and...

  15. [Effect of magnitude and duration on the performance of Cumulative Sum].

    PubMed

    Zhou, Ding-lun; Yang, Wei-zhong; Lan, Ya-jia; Li, Zhong-jie

    2012-06-01

    To explore the effect of magnitude and duration on the performance of Cumulative Sum (CUSUM), with simulation method used on the subject after the insertion of 11 outbreak events into baseline data with Poisson distribution. Sensitivity fluctuated from 9.1% to 100.0% with specificities higher than 98.6%. Sensitivity was significantly correlated with magnitude, and increased along with the increase of magnitude. However, no significant correlation was observed between sensitivity and duration. A magnitude which was at least 2.6 times higher than that of the mean daily baseline could result in the sensitivity of 100.0%. Time-lag would be improved along with the increase of magnitude. Time between onset and detection of an outbreak was no longer than one day when magnitude was more than 1.8 of the mean daily baseline. In summary, the performance of CUSUM was influenced by magnitude, but not by duration. CUSUM had the advantage of good time-lag and high sensitivity when the outbreak magnitude was more than 2.4 time over the baseline data.

  16. 48 CFR 236.204 - Disclosure of the magnitude of construction projects.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 3 2011-10-01 2011-10-01 false Disclosure of the magnitude of construction projects. 236.204 Section 236.204 Federal Acquisition Regulations System DEFENSE... magnitude of construction projects. Additional price ranges are— (i) Between $10,000,000 and...

  17. 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…

  18. 48 CFR 236.204 - Disclosure of the magnitude of construction projects.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Disclosure of the magnitude of construction projects. 236.204 Section 236.204 Federal Acquisition Regulations System DEFENSE... magnitude of construction projects. Additional price ranges are— (i) Between $10,000,000 and...

  19. Numerical magnitude affects online execution, and not planning of visuomotor control.

    PubMed

    Namdar, Gal; Ganel, Tzvi

    2017-01-20

    Recent literature has established a directional influence of irrelevant numerical magnitude on actions performed toward neutral objects. For example, fingers' aperture during grasping is larger when associated with large compared with small numerical digits. This interaction between symbolic magnitude and visuomotor control has been attributed to the planning stage of the action prior to motor execution. However, this assumption has not been directly tested. In two experiments, we tested whether the effects of numerical magnitude on grasping derive from action planning or from action execution. Participants were asked to grasp an object following a short visual (Experiment 1) or auditory (Experiment 2) presentation of small (1/2) or large (8/9) digits. Grasping was performed under either closed-loop (CL) or open-loop (OL) visuomotor control, for which online vision was prevented during action execution. Digit magnitude affected grip apertures in the CL condition, when online vision was allowed. However, magnitude had no effects on grip aperture in the OL condition. This pattern of results strongly suggests that the processing of numerical magnitude originates from interactions between numerical magnitude and real object size during online motor execution. Unlike previously assumed, the findings also suggest that the effect of magnitude on visuomotor control is not likely to be attributed to the motor planning stage prior to action initiation.

  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. Representations of Numerical and Non-Numerical Magnitude Both Contribute to Mathematical Competence in Children

    ERIC Educational Resources Information Center

    Lourenco, Stella F.; Bonny, Justin W.

    2017-01-01

    A growing body of evidence suggests that non-symbolic representations of number, which humans share with nonhuman animals, are functionally related to uniquely human mathematical thought. Other research suggesting that numerical and non-numerical magnitudes not only share analog format but also form part of a general magnitude system raises…

  2. 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…

  3. Delay of Gratification in Children: A Function of Magnitude of Reward and the Delay Cue

    ERIC Educational Resources Information Center

    Montgomery, Gary T.

    1976-01-01

    The delay and magnitude of reward cues were independently varied to investigate whether children's delay of gratification choices were attributable to (1) the magnitude of reward cue, and/or (2) discriminative stimulus properties of the delay cue. (Author/SB)

  4. 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…

  5. 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.

  6. Numerical magnitude processing deficits in children with mathematical difficulties are independent of intelligence.

    PubMed

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

    2014-11-01

    Developmental dyscalculia (DD) is thought to arise from difficulties in the ability to process numerical magnitudes. Most research relied on IQ-discrepancy based definitions of DD and only included individuals with normal IQ, yet little is known about the role of intelligence in the association between numerical magnitude processing and mathematical difficulties (MD). The present study examined numerical magnitude processing in matched groups of 7- to 8-year-olds (n=42) who had either discrepant MD (poor math scores, average IQ), nondiscrepant MD (poor math scores, below-average IQ) or no MD. Both groups of children with MD showed similar impairments in numerical magnitudes processing compared to controls, suggesting that the association between numerical magnitude processing deficits and MD is independent of intelligence. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Spatiotemporal evolution of the completeness magnitude of the Icelandic earthquake catalogue from 1991 to 2013

    NASA Astrophysics Data System (ADS)

    Panzera, Francesco; Mignan, Arnaud; Vogfjörð, Kristin S.

    2016-11-01

    In 1991, a digital seismic monitoring network was installed in Iceland with a digital seismic system and automatic operation. After 20 years of operation, we explore for the first time its nationwide performance by analysing the spatiotemporal variations of the completeness magnitude. We use the Bayesian magnitude of completeness (BMC) method that combines local completeness magnitude observations with prior information based on the density of seismic stations. Additionally, we test the impact of earthquake location uncertainties on the BMC results, by filtering the catalogue using a multivariate analysis that identifies outliers in the hypocentre error distribution. We find that the entire North-to-South active rift zone shows a relatively low magnitude of completeness Mc in the range 0.5-1.0, highlighting the ability of the Icelandic network to detect small earthquakes. This work also demonstrates the influence of earthquake location uncertainties on the spatiotemporal magnitude of completeness analysis.

  8. 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.

  9. Dealing with Big Numbers: Representation and Understanding of Magnitudes Outside of Human Experience.

    PubMed

    Resnick, Ilyse; Newcombe, Nora S; Shipley, Thomas F

    2017-05-01

    Being able to estimate quantity is important in everyday life and for success in the STEM disciplines. However, people have difficulty reasoning about magnitudes outside of human perception (e.g., nanoseconds, geologic time). This study examines patterns of estimation errors across temporal and spatial magnitudes at large scales. We evaluated the effectiveness of hierarchical alignment in improving estimations, and transfer across dimensions. The activity was successful in increasing accuracy for temporal and spatial magnitudes, and learning transferred to the estimation of numeric magnitudes associated with events and objects. However, there were also a number of informative differences in performance on temporal, spatial, and numeric magnitude measures, suggesting that participants possess different categorical information for these scales. Educational implications are discussed. Copyright © 2016 Cognitive Science Society, Inc.

  10. 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.

  11. Missing texture reconstruction method based on error reduction algorithm using Fourier transform magnitude estimation scheme.

    PubMed

    Ogawa, Takahiro; Haseyama, Miki

    2013-03-01

    A missing texture reconstruction method based on an error reduction (ER) algorithm, including a novel estimation scheme of Fourier transform magnitudes is presented in this brief. In our method, Fourier transform magnitude is estimated for a target patch including missing areas, and the missing intensities are estimated by retrieving its phase based on the ER algorithm. Specifically, by monitoring errors converged in the ER algorithm, known patches whose Fourier transform magnitudes are similar to that of the target patch are selected from the target image. In the second approach, the Fourier transform magnitude of the target patch is estimated from those of the selected known patches and their corresponding errors. Consequently, by using the ER algorithm, we can estimate both the Fourier transform magnitudes and phases to reconstruct the missing areas.

  12. The Surface Wave Magnitude for the 9 October 2006 North Korean Nuclear Explosion

    SciTech Connect

    Bonner, J; Herrmann, R; Harkrider, D; Pasyanos, M

    2008-03-11

    Surface waves were generated by the North Korean nuclear explosion of 9 October 2006 and recorded at epicentral distances up to 34 degrees, from which we estimated a surface wave magnitude (M{sub s}) of 2.94 with an interstation standard deviation of 0.17 magnitude units. The International Data Centre estimated a body wave magnitude (m{sub b}) of 4.1. This is the only explosion we have analyzed that was not easily screened as an explosion based on the differences between the M{sub s} and m{sub b} estimates. Additionally, this M{sub s} predicts a yield, based on empirical M{sub s}/Yield relationships, that is almost an order of magnitude larger then the 0.5 to 1 kiloton reported for this explosion. We investigate how emplacement medium effects on surface wave moment and magnitude may have contributed to the yield discrepancy.

  13. Spatiotemporal evolution of the completeness magnitude of the Icelandic earthquake catalogue from 1991 to 2013

    NASA Astrophysics Data System (ADS)

    Panzera, Francesco; Mignan, Arnaud; Vogfjörð, Kristin S.

    2017-07-01

    In 1991, a digital seismic monitoring network was installed in Iceland with a digital seismic system and automatic operation. After 20 years of operation, we explore for the first time its nationwide performance by analysing the spatiotemporal variations of the completeness magnitude. We use the Bayesian magnitude of completeness (BMC) method that combines local completeness magnitude observations with prior information based on the density of seismic stations. Additionally, we test the impact of earthquake location uncertainties on the BMC results, by filtering the catalogue using a multivariate analysis that identifies outliers in the hypocentre error distribution. We find that the entire North-to-South active rift zone shows a relatively low magnitude of completeness Mc in the range 0.5-1.0, highlighting the ability of the Icelandic network to detect small earthquakes. This work also demonstrates the influence of earthquake location uncertainties on the spatiotemporal magnitude of completeness analysis.

  14. An Updated Catalog of Taiwan Earthquakes (1900-2011) with Homogenized Mw Magnitudes

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    A complete and consistent catalog of earthquakes can provide good data for studying the distribution of earthquakes in a region as function of space, time and magnitude. Therefore, it is a basic tool for studying seismic hazard and mitigating hazard, and we can get the seismicity with magnitude equal to or greater than Mw from the data set. In the article for completeness and consistence, we apply a catalog of earthquakes from 1900 to 2006 with homogenized magnitude (Mw) (Chen and Tsai, 2008) as a base, and we also refer to the Hsu (1989) to incorporate available supplementary data (total 188 data) for the period 1900-1935, the supplementary data lead the cutoff threshold magnitude to be from Mw 5.5 down to 5.0, this indicates that we add the additional data has enriched the magnitude > 5.0 content. For this study, the catalog has been updated to include earthquakes up to 2011, and it is complete for Mw > 5.0, this will increase the reliability for studying seismic hazard. It is found that it is saturated for original catalog of Taiwan earthquakes compared with Harvard Mw or USGS M for magnitude > 6.5. Although, we modified the original catalog into seismic moment magnitude Mw, it still does not overcome the drawback. But, it is found for Mw < 6.5, our unified Mw are most greater than Harvard Mw or USGS M, the phenomenon indicates our unified Mw to supplement the gap above magnitude > 6.0 and somewhere magnitude > 5.5 during the time period 1973-1991 for original catalog. Therefore, it is better with Mw to report the earthquake magnitude.

  15. Exposure to Varying Strain Magnitudes Influences the Conversion of Normal Skin Fibroblasts Into Hypertrophic Scar Cells.

    PubMed

    Kuang, Ruixia; Wang, Zhiguo; Xu, Quanchen; Cai, Xia; Liu, Tao

    2016-04-01

    Mechanical strain is a key contributor in the pathogenesis of hypertrophic scarring, whose optimal stretch magnitudes to initiate the differentiation of normal skin fibroblasts into aberrant fibroblasts phenotype remains largely unresolved. Influence of varying cyclic strain magnitudes on cultured human normal skin fibroblasts and its transformation into hypertrophic scar fibroblast-like phenotype is investigated in this study. Cultured fibroblasts isolated from hypertrophic scar and normal skin tissue were subjected to cyclic mechanical stretching under individual 10%, 15%, and 20% strain magnitudes at a frequency of 0.1 Hz for 24 hours. Stretched normal skin fibroblasts demonstrated significantly increased rates of cell proliferation, and also apparently oriented away nearly perpendicular to the applied stretching direction. Interestingly, the applied 10% strains magnitude resulted in a markedly enhanced cell proliferative ability compared with that of 20% strain magnitude. Parameters involving the mechanotransduction signaling, such as integrin β1 and P130Cas, were significantly improved at both mRNA and protein levels in the stretched normal skin fibroblasts, which was demonstrated in a negative magnitude-dependent manner. In addition, 10% strains magnitude triggered the highest expression levels of growth factor TGF-β1 and collagen matrix in stretched normal skin fibroblasts. Collectively, these results indicate that the 10% stretching magnitude, of the 3 strain magnitudes studied, is most effective for triggering the optimal mechanotransduction effects and biological responses inside cultured skin fibroblasts. The demonstrable conversion of normal skin fibroblasts into hypertrophic scar fibroblasts was also observed when 10% stretching magnitude was applied to cultured fibroblasts in vitro.

  16. Joint maximum-likelihood magnitudes of presumed underground nuclear test explosions

    NASA Astrophysics Data System (ADS)

    Peacock, Sheila; Douglas, Alan; Bowers, David

    2017-08-01

    Body-wave magnitudes (mb) of 606 seismic disturbances caused by presumed underground nuclear test explosions at specific test sites between 1964 and 1996 have been derived from station amplitudes collected by the International Seismological Centre (ISC), by a joint inversion for mb and station-specific magnitude corrections. A maximum-likelihood method was used to reduce the upward bias of network mean magnitudes caused by data censoring, where arrivals at stations that do not report arrivals are assumed to be hidden by the ambient noise at the time. Threshold noise levels at each station were derived from the ISC amplitudes using the method of Kelly and Lacoss, which fits to the observed magnitude-frequency distribution a Gutenberg-Richter exponential decay truncated at low magnitudes by an error function representing the low-magnitude threshold of the station. The joint maximum-likelihood inversion is applied to arrivals from the sites: Semipalatinsk (Kazakhstan) and Novaya Zemlya, former Soviet Union; Singer (Lop Nor), China; Mururoa and Fangataufa, French Polynesia; and Nevada, USA. At sites where eight or more arrivals could be used to derive magnitudes and station terms for 25 or more explosions (Nevada, Semipalatinsk and Mururoa), the resulting magnitudes and station terms were fixed and a second inversion carried out to derive magnitudes for additional explosions with three or more arrivals. 93 more magnitudes were thus derived. During processing for station thresholds, many stations were rejected for sparsity of data, obvious errors in reported amplitude, or great departure of the reported amplitude-frequency distribution from the expected left-truncated exponential decay. Abrupt changes in monthly mean amplitude at a station apparently coincide with changes in recording equipment and/or analysis method at the station.

  17. 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

  18. 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.

  19. The association between children's numerical magnitude processing and mental multi-digit subtraction.

    PubMed

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

    2014-01-01

    Children apply various strategies to mentally solve multi-digit subtraction problems and the efficient use of some of them may depend more or less on numerical magnitude processing. For example, the indirect addition strategy (solving 72-67 as "how much do I have to add up to 67 to get 72?"), which is particularly efficient when the two given numbers are close to each other, requires to determine the proximity of these two numbers, a process that may depend on numerical magnitude processing. In the present study, children completed a numerical magnitude comparison task and a number line estimation task, both in a symbolic and nonsymbolic format, to measure their numerical magnitude processing. We administered a multi-digit subtraction task, in which half of the items were specifically designed to elicit indirect addition. Partial correlational analyses, controlling for intellectual ability and motor speed, revealed significant associations between numerical magnitude processing and mental multi-digit subtraction. Additional analyses indicated that numerical magnitude processing was particularly important for those items for which the use of indirect addition is expected to be most efficient. Although this association was observed for both symbolic and nonsymbolic tasks, the strongest associations were found for the symbolic format, and they seemed to be more prominent on numerical magnitude comparison than on number line estimation.

  20. Methods for estimating magnitude and frequency of floods in Montana based on data through 1983

    USGS Publications Warehouse

    Omang, R.J.; Parrett, Charles; Hull, J.A.

    1986-01-01

    Equations are presented for estimating flood magnitudes for ungaged sites in Montana based on data through 1983. The State was divided into eight regions based on hydrologic conditions, and separate multiple regression equations were developed for each region. These equations relate annual flood magnitudes and frequencies to basin characteristics and are applicable only to natural flow streams. In three of the regions, equations also were developed relating flood magnitudes and frequencies to basin characteristics and channel geometry measurements. The standard errors of estimate for an exceedance probability of 1% ranged from 39% to 87%. Techniques are described for estimating annual flood magnitude and flood frequency information at ungaged sites based on data from gaged sites on the same stream. Included are curves relating flood frequency information to drainage area for eight major streams in the State. Maximum known flood magnitudes in Montana are compared with estimated 1 %-chance flood magnitudes and with maximum known floods in the United States. Values of flood magnitudes for selected exceedance probabilities and values of significant basin characteristics and channel geometry measurements for all gaging stations used in the analysis are tabulated. Included are 375 stations in Montana and 28 nearby stations in Canada and adjoining States. (Author 's abstract)

  1. Probability of inducing given-magnitude earthquakes by perturbing finite volumes of rocks

    NASA Astrophysics Data System (ADS)

    Shapiro, Serge A.; Krüger, Oliver S.; Dinske, Carsten

    2013-07-01

    Fluid-induced seismicity results from an activation of finite rock volumes. The finiteness of perturbed volumes influences frequency-magnitude statistics. Previously we observed that induced large-magnitude events at geothermal and hydrocarbon reservoirs are frequently underrepresented in comparison with the Gutenberg-Richter law. This is an indication that the events are more probable on rupture surfaces contained within the stimulated volume. Here we theoretically and numerically analyze this effect. We consider different possible scenarios of event triggering: rupture surfaces located completely within or intersecting only the stimulated volume. We approximate the stimulated volume by an ellipsoid or cuboid and derive the statistics of induced events from the statistics of random thin flat discs modeling rupture surfaces. We derive lower and upper bounds of the probability to induce a given-magnitude event. The bounds depend strongly on the minimum principal axis of the stimulated volume. We compare the bounds with data on seismicity induced by fluid injections in boreholes. Fitting the bounds to the frequency-magnitude distribution provides estimates of a largest expected induced magnitude and a characteristic stress drop, in addition to improved estimates of the Gutenberg-Richter a and b parameters. The observed frequency-magnitude curves seem to follow mainly the lower bound. However, in some case studies there are individual large-magnitude events clearly deviating from this statistic. We propose that such events can be interpreted as triggered ones, in contrast to the absolute majority of the induced events following the lower bound.

  2. 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.

  3. 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.

  4. 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.

  5. Cross-modal effects of auditory magnitude on visually guided grasping.

    PubMed

    Namdar, Gal; Ganel, Tzvi

    2015-01-01

    Recent research has established the role of objects' semantic properties in the planning of motor actions with respect to these objects. It has been shown that visual numerical magnitude affects visuomotor control in a similar direction to the effect of physical size: The larger the numerical value, the larger the grip aperture even when physical size remains invariant. The relationship has been attributed to a common mechanism, in particular to a neural network within the parietal lobe, which mediates the processing of magnitude across different domains. In this study, we show that the effect of magnitude on grasping is not limited to visual numerical information and is in fact cross-modal in nature; presentations of auditory signals of different types of auditory-based magnitudes affected visually guided actions in two different experiments. In Experiment 1, symbolic representations of magnitudes (numerals) affected initial grasping trajectories. In Experiment 2, a nonsymbolic presentation of magnitude, i.e., tone duration, had similar effects on grasping trajectories. We conclude that different types of magnitude representations are processed by a common mechanism that cooperates with visuomotor control.

  6. 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

  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.

  8. 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.

  9. 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.

  10. 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.

  11. Interaction of frequency and magnitude of reinforcement on concurrent performances1

    PubMed Central

    Todorov, Joao Claudio

    1973-01-01

    Frequency and magnitude of reinforcement were varied in concurrent variable-interval variable-interval schedules of reinforcement. The relative response rate to the two stimuli did not support the notion that choice approximately matches relative total access to food (the product of frequency and magnitude of reinforcement in one schedule divided by the sum of products of frequency and magnitude in both schedules). Relative response rates matched relative reinforcement value when that measure was adjusted to give more emphasis to reinforcement frequency than to reinforcement duration. PMID:16811675

  12. 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.

  13. 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.

  14. 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

  15. 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

  16. 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.

  17. Arithmetic word problem solving: evidence for a magnitude-based mental representation.

    PubMed

    Orrantia, Josetxu; Múñez, David

    2013-01-01

    Previous findings have suggested that number processing involves a mental representation of numerical magnitude. Other research has shown that sensory experiences are part and parcel of the mental representation (or "simulation") that individuals construct during reading. We aimed at exploring whether arithmetic word-problem solving entails the construction of a mental simulation based on a representation of numerical magnitude. Participants were required to solve word problems and to perform an intermediate figure discrimination task that matched or mismatched, in terms of magnitude comparison, the mental representations that individuals constructed during problem solving. Our results showed that participants were faster in the discrimination task and performed better in the solving task when the figures matched the mental representations. These findings provide evidence that an analog magnitude-based mental representation is routinely activated during word-problem solving, and they add to a growing body of literature that emphasizes the experiential view of language comprehension.

  18. 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

  19. 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.

  20. Sound energy and the magnitude of change: effects on mismatch negativity.

    PubMed

    Takegata, Rika; Heikkilä, Roope; Näätänen, Risto

    2011-03-09

    The mismatch negativity (MMN) of event-related potential generally increases in amplitude, as a function of magnitude of change. This study examined whether this relation holds true for intensity decrement, in which the stimulus energy that conveys the change falls in inverse proportion to magnitude of change. The MMN was recorded from healthy young adults for intensity decrements of 10, 20, 30, 40, and 50 dB. As the change increased, the MMN amplitude also increased first and thereafter diminished; thus, an inverted U-shaped relation was found between the MMN amplitude and the magnitude of change. These results, therefore, suggest a possible interplay between the energy of deviant stimulus and magnitude of change in the MMN elicitation.

  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. Analysis of color-magnitude diagrams from three Large Magellanic Cloud clusters

    NASA Astrophysics Data System (ADS)

    Jones, J. H.

    The color-magnitude diagrams of three large Magellanic Cloud (LMC) clusters and a field were derived from photographic and CCD data provided by Dr. P. J. Flower of Clemson University and Dr. R. Schommer of Rutgers University. The photographic data were scanned and converted to intensity images at KPNO. The stellar photometry program RICHFLD was used to measure the raw magnitudes from these images. Problems with the standard sequence on the plate kept the color terms for the photographic data from being well determined. A version of DAOPHOT was installed on the VAX 11/280s at Clemson and was used to measure the magnitudes from the CCD images of NGC 2249. These magnitudes were used to define another photoelectric sequence for the photographic data which were used to determine a well defined transformation into the standard BV system.

  3. Floods in western Washington--Frequency and magnitude in relation to drainage basin characteristics

    USGS Publications Warehouse

    Bodhaine, G.L.; Robinson, W.H.

    1952-01-01

    Included in the report are curves of magnitude and frequency of floods at all gaging stations in the region with 15 or more years of record. Also included is an enveloping curve of the maximum recorded discharges in the region.

  4. '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.

  5. Understanding volatility correlation behavior with a magnitude cross-correlation function

    NASA Astrophysics Data System (ADS)

    Jun, Woo Cheol; Oh, Gabjin; Kim, Seunghwan

    2006-06-01

    We propose an approach for analyzing the basic relation between correlation properties of the original signal and its magnitude fluctuations by decomposing the original signal into its positive and negative fluctuation components. We use this relation to understand the following phenomenon found in many naturally occurring time series: the magnitude of the signal exhibits long-range correlation, whereas the original signal is short-range correlated. The applications of our approach to heart rate variability signals and high-frequency foreign exchange rates reveal that the difference between the correlation properties of the original signal and its magnitude fluctuations is induced by the time organization structure of the correlation function between the magnitude fluctuations of positive and negative components. We show that this correlation function can be described well by a stretched-exponential function and is related to the nonlinearity and the multifractal structure of the signals.

  6. The development of the mental representations of the magnitude of fractions.

    PubMed

    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.

  7. Has the magnitude of floods across the USA changed with global CO2 levels?

    USGS Publications Warehouse

    Hirsch, Robert M.; Ryberg, Karen 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.

  8. 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.

  9. ESTIMATION OF RESPONSE-SPECTRAL VALUES AS FUNCTIONS OF MAGNITUDE, DISTANCE, AND SITE CONDITIONS.

    USGS Publications Warehouse

    Joyner, W.B.; Boore, D.M.; ,

    1983-01-01

    Horizontal pseudo-velocity response was analyzed for twelve shallow earthquakes in western North America. Estimation of response-spectral values was related to magnitude, distance and site conditions. Errors in the methods are analyzed.

  10. Symbolic and non-symbolic number magnitude processing in children with developmental dyscalculia.

    PubMed

    Castro Cañizares, Danilka; Reigosa Crespo, Vivian; González Alemañy, Eduardo

    2012-11-01

    The aim of this study was to evaluate if children with Developmental Dyscalculia (DD) exhibit a general deficit in magnitude representations or a specific deficit in the connection of symbolic representations with the corresponding analogous magnitudes. DD was diagnosed using a timed arithmetic task. The experimental magnitude comparison tasks were presented in non-symbolic and symbolic formats. DD and typically developing (TD) children showed similar numerical distance and size congruity effects. However, DD children performed significantly slower in the symbolic task. These results are consistent with the access deficit hypothesis, according to which DD children's deficits are caused by difficulties accessing magnitude information from numerical symbols rather than in processing numerosities per se.

  11. 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.

  12. 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.

  13. Examining pitch and numerical magnitude processing in congenital amusia: A quasi-experimental pilot study.

    PubMed

    Nunes-Silva, Marilia; Moura, Ricardo; Lopes-Silva, Júlia Beatriz; Haase, Vitor Geraldi

    2016-08-01

    Congenital amusia is a developmental disorder associated with deficits in pitch height discrimination or in integrating pitch sequences into melodies. This quasi-experimental pilot study investigated whether there is an association between pitch and numerical processing deficits in congenital amusia. Since pitch height discrimination is considered a form of magnitude processing, we investigated whether individuals with amusia present an impairment in numerical magnitude processing, which would reflect damage to a generalized magnitude system. Alternatively, we investigated whether the numerical processing deficit would reflect a disconnection between nonsymbolic and symbolic number representations. This study was conducted with 11 adult individuals with congenital amusia and a control comparison group of 6 typically developing individuals. Participants performed nonsymbolic and symbolic magnitude comparisons and number line tasks. Results were available from previous testing using the Montreal Battery of Evaluation of Amusia (MBEA) and a pitch change detection task (PCD). Compared to the controls, individuals with amusia exhibited no significant differences in their performance on both the number line and the nonsymbolic magnitude tasks. Nevertheless, they showed significantly worse performance on the symbolic magnitude task. Moreover, individuals with congenital amusia, who presented worse performance in the Meter subtest, also presented less precise nonsymbolic numerical representation. The relationship between meter and nonsymbolic numerical discrimination could indicate a general ratio processing deficit. The finding of preserved nonsymbolic numerical magnitude discrimination and mental number line representations, with impaired symbolic number processing, in individuals with congenital amusia indicates that (a) pitch height and numerical magnitude processing may not share common neural representations, and (b) in addition to pitch processing, individuals with

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

    NASA Astrophysics Data System (ADS)

    Cheek, Kim A.

    2017-08-01

    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.

  15. 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.

  16. Analysis of the Anomalous Surface Wave Magnitudes for the North Korean Nuclear Explosions

    NASA Astrophysics Data System (ADS)

    Bonner, J. L.; Herrmann, R. B.

    2009-12-01

    The surface wave magnitudes (Ms) estimated from Rayleigh waves generated by the 9 October 2006 and 25 May 2009 North Korean nuclear explosions were 2.9 and 3.6, respectively. When these estimates were related to the body-wave magnitudes (mb) reported for these events (e.g., 4.1 and 4.6), the surface wave magnitudes were anomalously large compared to typical nuclear explosions. When using these Ms values to predict the yields of the explosions, the estimates were an order of magnitude larger than yields estimated from body-wave techniques. In this paper, we present our surface wave analysis for these explosions. We provide estimates of the surface wave magnitudes for both the Love and Rayleigh waves generated by these explosions with comparison to other nuclear test sites. For example, the Love-wave Ms for the 25 May 2009 event was 0.6 magnitude units smaller than the Rayleigh-wave magnitude, which is a larger difference than noted for any other historic nuclear test site. This provides qualitative evidence of the largely isotropic nature of these explosions. We further quantify this by providing moment estimates for each explosion based on surface wave modeling. We then use these moments to estimate yields based on velocity structures inferred near the North Korean test site for comparison to body-wave yield estimates. We also compare the moments and magnitudes to numerous earthquakes in the Korean Peninsula for which similar analyses have been completed. We hope to determine the phenomena behind these large explosion-generated Rayleigh waves, with possible explanations including path effects, the largely isotropic components of these explosions, or the test site velocity structure.

  17. 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.

  18. Relative reinforcer rates and magnitudes do not control concurrent choice independently.

    PubMed

    Elliffe, Douglas; Davison, Michael; Landon, Jason

    2008-09-01

    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 schedules. Across conditions, the ratios of reinforcer rates and of reinforcer magnitudes on the two alternatives were both manipulated. Control by each independent variable, as measured by generalized-matching sensitivity, changed significantly with the ratio of the other independent variable. Analyses taking the model-comparison approach, which weighs improvement in goodness-of-fit against increasing number of free parameters, were inconclusive. These analyses compared a model assuming constant sensitivity to magnitude across all reinforcer-rate ratios with two alternative models. One of those alternatives allowed sensitivity to magnitude to vary freely across reinforcer-rate ratios, and was less efficient than the common-sensitivity model for all pigeons, according to the Schwarz-Bayes information criterion. The second alternative model constrained sensitivity to magnitude to be equal for pairs of reinforcer-rate ratios that deviated from unity by proportionately equal amounts but in opposite directions. This model was more efficient than the common-magnitude-sensitivity model for 2 of the pigeons, but not for the other 3. An analysis of variance, carried out independently of the generalized-matching analysis, also showed a significant interaction between the effects of reinforcer rate and reinforcer magnitude on choice. On balance, these results suggest that the assumption of independence inherent in the matching approach cannot be maintained. Relative reinforcer rates and magnitudes do not control choice independently.

  19. Reinforcement magnitude modulation of rate dependent effects in pigeons and rats.

    PubMed

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

    2011-08-01

    Response rate can influence the behavioral effects of many drugs. Reinforcement magnitude may also influence drug effects. Further, reinforcement magnitude can influence rate-dependent effects. For example, in an earlier report, we showed that rate-dependent effects of two antidepressants depended on reinforcement magnitude. The ability of reinforcement magnitude to interact with rate-dependency has not been well characterized. It is not known whether our previous results are specific to antidepressants or generalize to other drug classes. Here, we further examine rate-magnitude interactions by studying effects of two stimulants (d-amphetamine [0.32-5.6 mg/kg] and cocaine [0.32-10 mg/kg]) and two sedatives (chlordiazepoxide [1.78-32 mg/kg] and pentobarbital [1.0-17.8 mg/kg]) in pigeons responding under a 3-component multiple fixed-interval (FI) 300-s schedule maintained by 2-, 4-, or 8-s of food access. We also examine the effects of d-amphetamine [0.32-3.2 mg/kg] and pentobarbital [1.8-10 mg/kg] in rats responding under a similar multiple FI300-s schedule maintained by 2- or 10- food pellet (45 mg) delivery. In pigeons, cocaine and, to a lesser extent, chlordiazepoxide exerted rate-dependent effects that were diminished by increasing durations of food access. The relationship was less apparent for pentobarbital, and not present for d-amphetamine. In rats, rate-dependent effects of pentobarbital and d-amphetamine were not modulated by reinforcement magnitude. In conclusion, some drugs appear to exert rate-dependent effect which are diminished when reinforcement magnitude is relatively high. Subsequent analysis of the rate-dependency data suggest the effects of reinforcement magnitude may be due to a diminution of drug-induced increases in low-rate behavior that occurs early in the fixed-interval.

  20. 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.